1
|
Wang JY, Song QL, Wang YL, Jiang ZM. Urinary oxygen tension and its role in predicting acute kidney injury: A narrative review. J Clin Anesth 2024; 93:111359. [PMID: 38061226 DOI: 10.1016/j.jclinane.2023.111359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Revised: 11/12/2023] [Accepted: 12/01/2023] [Indexed: 01/14/2024]
Abstract
Acute kidney injury occurs frequently in the perioperative setting. The renal medulla often endures hypoxia or hypoperfusion and is susceptible to the imbalance between oxygen supply and demand due to the nature of renal blood flow distribution and metabolic rate in the kidney. The current available evidence demonstrated that the urine oxygen pressure is proportional to the variations of renal medullary tissue oxygen pressure. Thus, urine oxygenation can be a candidate for reflecting the change of oxygen in the renal medulla. In this review, we discuss the basic physiology of acute kidney injury, as well as techniques for monitoring urine oxygen tension, confounding factors affecting the reliable measurement of urine oxygen tension, and its clinical use, highlighting its potential role in early detection and prevention of acute kidney injury.
Collapse
Affiliation(s)
- Jing-Yan Wang
- Department of Anesthesia, Shaoxing People's Hospital, Shaoxing 312000, Zhejiang Province, China
| | - Qi-Liang Song
- Department of Anesthesia, Shaoxing People's Hospital, Shaoxing 312000, Zhejiang Province, China
| | - Yu-Long Wang
- Department of Anesthesia, Shaoxing People's Hospital, Shaoxing 312000, Zhejiang Province, China
| | - Zong-Ming Jiang
- Department of Anesthesia, Shaoxing People's Hospital, Shaoxing 312000, Zhejiang Province, China.
| |
Collapse
|
2
|
Kawakami S, Yasuno T, Kotoku K, Kawakami S, Ito A, Fujimi K, Matsuda T, Nakashima S, Masutani K, Uehara Y, Higaki Y, Michishita R. The differences in renal hemodynamic response following high-intensity exercise between younger and older males. Clin Exp Nephrol 2023; 27:972-980. [PMID: 37450106 DOI: 10.1007/s10157-023-02381-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2023] [Accepted: 07/07/2023] [Indexed: 07/18/2023]
Abstract
BACKGROUND Renal blood flow (RBF) decreases with exercise, but this change is only temporary, and habitual exercise may be an effective method to improve renal function. The kidney shows structural and functional changes with aging, but it is unclear how aging affects the hemodynamic response of the kidneys to exercise. Therefore, we evaluated the differences in the hemodynamic response of the kidneys to high-intensity exercise between younger and older men. METHODS Sixteen men (8 young and 8 older) underwent an incremental exercise test using a cycle ergometer with a 1-min warm up followed by exercise at 10-20 W/min until the discontinuation criteria were met. Renal hemodynamics were assessed before exercise, immediately after exercise, and at 60-min after exercise using ultrasound echo. RESULTS High-intensity exercise significantly reduced RBF in both groups (younger: ∆ - 53 ± 16%, p = 0.0005; older: ∆ - 53 ± 19%, p = 0.0004). In the younger group, RBF returned to the pre-exercise level 60-min after exercise (∆ - 0.4 ± 5.7%, p > 0.9999). In contrast, RBF 60-min after exercise was significantly lower than that before exercise in the older group (∆ - 24 ± 19%, p = 0.0006). The older group had significantly lower RBF than younger adults 60-min after exercise (423 ± 32 vs. 301 ± 98 mL/min, p = 0.0283). CONCLUSIONS Our findings demonstrate that RBF following high-intensity exercise recovered 60-min after exercise in younger group, whereas RBF recovery was delayed in the older group.
Collapse
Affiliation(s)
- Shotaro Kawakami
- Graduate School of Sports and Health Science, Fukuoka University, Fukuoka, Japan
- Faculty of Sports and Health Science, Fukuoka University, Fukuoka, Japan
- The Fukuoka University Institute for Physical Activity, Fukuoka, Japan
| | - Tetsuhiko Yasuno
- Division of Nephrology and Rheumatology, Department of Internal Medicine, Fukuoka University School of Medicine, Fukuoka, Japan
| | - Kazuko Kotoku
- Faculty of Fukuoka Medical Technology, Teikyo University, 6-22, Misaki-Machi, Omuta-Shi, Fukuoka, Japan
| | - Saki Kawakami
- The Fukuoka University Institute for Physical Activity, Fukuoka, Japan
| | - Ai Ito
- The Fukuoka University Institute for Physical Activity, Fukuoka, Japan
| | - Kanta Fujimi
- Department of Rehabilitation, Fukuoka University Hospital, Fukuoka, Japan
| | - Takuro Matsuda
- Department of Rehabilitation, Fukuoka University Hospital, Fukuoka, Japan
| | - Shihoko Nakashima
- Faculty of Sports and Health Science, Fukuoka University, Fukuoka, Japan
- The Fukuoka University Institute for Physical Activity, Fukuoka, Japan
| | - Kosuke Masutani
- Division of Nephrology and Rheumatology, Department of Internal Medicine, Fukuoka University School of Medicine, Fukuoka, Japan
| | - Yoshinari Uehara
- Faculty of Sports and Health Science, Fukuoka University, Fukuoka, Japan
- The Fukuoka University Institute for Physical Activity, Fukuoka, Japan
| | - Yasuki Higaki
- Faculty of Sports and Health Science, Fukuoka University, Fukuoka, Japan
- The Fukuoka University Institute for Physical Activity, Fukuoka, Japan
| | - Ryoma Michishita
- Faculty of Sports and Health Science, Fukuoka University, Fukuoka, Japan.
- The Fukuoka University Institute for Physical Activity, Fukuoka, Japan.
| |
Collapse
|
3
|
Betrie AH, Ma S, Ow CPC, Peiris RM, Evans RG, Ayton S, Lane DJR, Southon A, Bailey SR, Bellomo R, May CN, Lankadeva YR. Renal arterial infusion of tempol prevents medullary hypoperfusion, hypoxia, and acute kidney injury in ovine Gram-negative sepsis. Acta Physiol (Oxf) 2023; 239:e14025. [PMID: 37548350 PMCID: PMC10909540 DOI: 10.1111/apha.14025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 07/05/2023] [Accepted: 07/21/2023] [Indexed: 08/08/2023]
Abstract
AIM Renal medullary hypoperfusion and hypoxia precede acute kidney injury (AKI) in ovine sepsis. Oxidative/nitrosative stress, inflammation, and impaired nitric oxide generation may contribute to such pathophysiology. We tested whether the antioxidant and anti-inflammatory drug, tempol, may modify these responses. METHODS Following unilateral nephrectomy, we inserted renal arterial catheters and laser-Doppler/oxygen-sensing probes in the renal cortex and medulla. Noanesthetized sheep were administered intravenous (IV) Escherichia coli and, at sepsis onset, IV tempol (IVT; 30 mg kg-1 h-1 ), renal arterial tempol (RAT; 3 mg kg-1 h-1 ), or vehicle. RESULTS Septic sheep receiving vehicle developed renal medullary hypoperfusion (76 ± 16% decrease in perfusion), hypoxia (70 ± 13% decrease in oxygenation), and AKI (87 ± 8% decrease in creatinine clearance) with similar changes during IVT. However, RAT preserved medullary perfusion (1072 ± 307 to 1005 ± 271 units), oxygenation (46 ± 8 to 43 ± 6 mmHg), and creatinine clearance (61 ± 10 to 66 ± 20 mL min-1 ). Plasma, renal medullary, and cortical tissue malonaldehyde and medullary 3-nitrotyrosine decreased significantly with sepsis but were unaffected by IVT or RAT. Consistent with decreased oxidative/nitrosative stress markers, cortical and medullary nuclear factor-erythroid-related factor-2 increased significantly and were unaffected by IVT or RAT. However, RAT prevented sepsis-induced overexpression of cortical tissue tumor necrosis factor alpha (TNF-α; 51 ± 16% decrease; p = 0.003) and medullary Thr-495 phosphorylation of endothelial nitric oxide synthase (eNOS; 63 ± 18% decrease; p = 0.015). CONCLUSIONS In ovine Gram-negative sepsis, renal arterial infusion of tempol prevented renal medullary hypoperfusion and hypoxia and AKI and decreased TNF-α expression and uncoupling of eNOS. However, it did not affect markers of oxidative/nitrosative stress, which were significantly decreased by Gram-negative sepsis.
Collapse
Affiliation(s)
- Ashenafi H. Betrie
- Preclinical Critical Care Unit, Florey Institute of Neuroscience and Mental HealthThe University of MelbourneMelbourneVictoriaAustralia
- Translational Neurodegeneration Laboratory, Florey Institute of Neuroscience and Mental HealthThe University of MelbourneMelbourneVictoriaAustralia
| | - Shuai Ma
- Preclinical Critical Care Unit, Florey Institute of Neuroscience and Mental HealthThe University of MelbourneMelbourneVictoriaAustralia
- Division of Nephrology, Shanghai Ninth People's HospitalShanghai Jiaotong University School of MedicineShanghaiChina
| | - Connie P. C. Ow
- Preclinical Critical Care Unit, Florey Institute of Neuroscience and Mental HealthThe University of MelbourneMelbourneVictoriaAustralia
| | - Rachel M. Peiris
- Preclinical Critical Care Unit, Florey Institute of Neuroscience and Mental HealthThe University of MelbourneMelbourneVictoriaAustralia
| | - Roger G. Evans
- Preclinical Critical Care Unit, Florey Institute of Neuroscience and Mental HealthThe University of MelbourneMelbourneVictoriaAustralia
- Biomedicine Discovery Institute and Department of PhysiologyMonash UniversityMelbourneVictoriaAustralia
| | - Scott Ayton
- Translational Neurodegeneration Laboratory, Florey Institute of Neuroscience and Mental HealthThe University of MelbourneMelbourneVictoriaAustralia
| | - Darius J. R. Lane
- Translational Neurodegeneration Laboratory, Florey Institute of Neuroscience and Mental HealthThe University of MelbourneMelbourneVictoriaAustralia
| | - Adam Southon
- Translational Neurodegeneration Laboratory, Florey Institute of Neuroscience and Mental HealthThe University of MelbourneMelbourneVictoriaAustralia
| | - Simon R. Bailey
- Faculty of Veterinary and Agricultural SciencesThe University of MelbourneMelbourneVictoriaAustralia
| | - Rinaldo Bellomo
- Department of Critical Care, Melbourne Medical SchoolThe University of MelbourneMelbourneVictoriaAustralia
- Australian and New Zealand Intensive Care Research CentreMonash UniversityMelbourneVictoriaAustralia
- Department of Intensive CareAustin HospitalMelbourneVictoriaAustralia
- Department of Intensive CareRoyal Melbourne HospitalMelbourneVictoriaAustralia
| | - Clive N. May
- Preclinical Critical Care Unit, Florey Institute of Neuroscience and Mental HealthThe University of MelbourneMelbourneVictoriaAustralia
- Department of Critical Care, Melbourne Medical SchoolThe University of MelbourneMelbourneVictoriaAustralia
| | - Yugeesh R. Lankadeva
- Preclinical Critical Care Unit, Florey Institute of Neuroscience and Mental HealthThe University of MelbourneMelbourneVictoriaAustralia
- Department of Critical Care, Melbourne Medical SchoolThe University of MelbourneMelbourneVictoriaAustralia
| |
Collapse
|
4
|
Jufar AH, Evans RG, May CN, Hood SG, Betrie AH, Trask‐Marino A, Bellomo R, Lankadeva YR. The effects of recruitment of renal functional reserve on renal cortical and medullary oxygenation in non-anesthetized sheep. Acta Physiol (Oxf) 2023; 237:e13919. [PMID: 36598336 PMCID: PMC10909474 DOI: 10.1111/apha.13919] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 11/18/2022] [Accepted: 01/02/2023] [Indexed: 01/05/2023]
Abstract
AIM Recruitment of renal functional reserve (RFR) with amino acid loading increases renal blood flow and glomerular filtration rate. However, its effects on renal cortical and medullary oxygenation have not been determined. Accordingly, we tested the effects of recruitment of RFR on renal cortical and medullary oxygenation in non-anesthetized sheep. METHODS Under general anesthesia, we instrumented 10 sheep to enable subsequent continuous measurements of systemic and renal hemodynamics, renal oxygen delivery and consumption, and cortical and medullary tissue oxygen tension (PO2 ). We then measured the effects of recruitment of RFR with an intravenous infusion of 500 ml of a clinically used amino acid solution (10% Synthamin® 17) in the non-anesthetized state. RESULTS Compared with baseline, Synthamin® 17 infusion significantly increased renal oxygen delivery mean ± SD maximum increase: (from 0.79 ± 0.17 to 1.06 ± 0.16 ml/kg/min, p < 0.001), renal oxygen consumption (from 0.08 ± 0.01 to 0.15 ± 0.02 ml/kg/min, p < 0.001), and glomerular filtration rate (+45.2 ± 2.7%, p < 0.001). Renal cortical tissue PO2 increased by a maximum of 26.4 ± 1.1% (p = 0.001) and medullary tissue PO2 increased by a maximum of 23.9 ± 2.8% (p = 0. 001). CONCLUSIONS In non-anesthetized healthy sheep, recruitment of RFR improved renal cortical and medullary oxygenation. These observations might have implications for the use of recruitment of RFR for diagnostic and therapeutic purposes.
Collapse
Affiliation(s)
- Alemayehu H. Jufar
- Pre‐Clinical Critical Care UnitFlorey Institute of Neuroscience and Mental Health, University of MelbourneMelbourneVictoriaAustralia
- Cardiovascular Disease Program, Department of PhysiologyBiomedicine Discovery Institute, Monash UniversityMelbourneVictoriaAustralia
| | - Roger G. Evans
- Pre‐Clinical Critical Care UnitFlorey Institute of Neuroscience and Mental Health, University of MelbourneMelbourneVictoriaAustralia
- Cardiovascular Disease Program, Department of PhysiologyBiomedicine Discovery Institute, Monash UniversityMelbourneVictoriaAustralia
| | - Clive N. May
- Pre‐Clinical Critical Care UnitFlorey Institute of Neuroscience and Mental Health, University of MelbourneMelbourneVictoriaAustralia
- Department of Critical CareMelbourne Medical School, University of MelbourneMelbourneVictoriaAustralia
| | - Sally G. Hood
- Pre‐Clinical Critical Care UnitFlorey Institute of Neuroscience and Mental Health, University of MelbourneMelbourneVictoriaAustralia
| | - Ashenafi H. Betrie
- Pre‐Clinical Critical Care UnitFlorey Institute of Neuroscience and Mental Health, University of MelbourneMelbourneVictoriaAustralia
- Melbourne Dementia Research CentreFlorey Institute of Neuroscience and Mental Health, The University of MelbourneMelbourneVictoriaAustralia
| | - Anton Trask‐Marino
- Pre‐Clinical Critical Care UnitFlorey Institute of Neuroscience and Mental Health, University of MelbourneMelbourneVictoriaAustralia
| | - Rinaldo Bellomo
- Pre‐Clinical Critical Care UnitFlorey Institute of Neuroscience and Mental Health, University of MelbourneMelbourneVictoriaAustralia
- Department of Critical CareMelbourne Medical School, University of MelbourneMelbourneVictoriaAustralia
| | - Yugeesh R. Lankadeva
- Pre‐Clinical Critical Care UnitFlorey Institute of Neuroscience and Mental Health, University of MelbourneMelbourneVictoriaAustralia
- Department of Critical CareMelbourne Medical School, University of MelbourneMelbourneVictoriaAustralia
| |
Collapse
|
5
|
Tao Y, Young‐Stubbs C, Yazdizadeh Shotorbani P, Su D, Mathis KW, Ma R. Sex and strain differences in renal hemodynamics in mice. Physiol Rep 2023; 11:e15644. [PMID: 36946063 PMCID: PMC10031302 DOI: 10.14814/phy2.15644] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 02/22/2023] [Accepted: 02/25/2023] [Indexed: 03/23/2023] Open
Abstract
The present study was to examine sex and strain differences in glomerular filtration rate (GFR) and renal blood flow (RBF) in C57BL6, 129/Sv, and C57BLKS/J mice, three commonly used mouse strains in renal research. GFR was measured by transdermal measurement of FITC-sinitrin clearance in conscious mice. RBF was measured by a flow probe placed in the renal artery under an anesthetic state. In C57BL6 mice, there were no sex differences in both GFR and RBF. In 129/Sv mice, females had significantly greater GFR than males at age of 24 weeks, but not at 8 weeks. However, males had higher RBF and lower renal vascular resistance (RVR). Similar to 129/Sv, female C57BLKS/J had significantly greater GFR at both 8 and 24 weeks, lower RBF, and higher RVR than males. Across strains, male 129/Sv had lower GFR and higher RBF than male C57BL6, but no significant difference in GFR and greater RBF than male C57BLKS/J. No significant difference in GFR or RBF was observed between C57BL6 and C57BLKS/J mice. Deletion of eNOS in C57BLKS/J mice reduced GFR in both sexes, but decreased RBF in males. Furthermore, there were no sex differences in the severity of renal injury in eNOS-/- dbdb mice. Taken together, our study suggests that sex differences in renal hemodynamics in mice are strain and age dependent. eNOS was not involved in the sex differences in GFR, but in RBF. Furthermore, the sexual dimorphism did not impact the severity of renal injury in diabetic nephropathy.
Collapse
Affiliation(s)
- Yu Tao
- Department of Physiology and AnatomyUniversity of North Texas Health Science CenterFort WorthTexasUSA
| | - Cassandra Young‐Stubbs
- Department of Physiology and AnatomyUniversity of North Texas Health Science CenterFort WorthTexasUSA
| | | | - Dong‐Ming Su
- Department of Microbiology, Immunology and GeneticsUniversity of North Texas Health Science CenterFort WorthTexasUSA
| | - Keisa W. Mathis
- Department of Physiology and AnatomyUniversity of North Texas Health Science CenterFort WorthTexasUSA
| | - Rong Ma
- Department of Physiology and AnatomyUniversity of North Texas Health Science CenterFort WorthTexasUSA
| |
Collapse
|
6
|
Echeverria‐Chasco R, Martin‐Moreno PL, Garcia‐Fernandez N, Vidorreta M, Aramendia‐Vidaurreta V, Cano D, Villanueva A, Bastarrika G, Fernández‐Seara MA. Multiparametric renal magnetic resonance imaging: A reproducibility study in renal allografts with stable function. NMR Biomed 2023; 36:e4832. [PMID: 36115029 PMCID: PMC10078573 DOI: 10.1002/nbm.4832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 09/13/2022] [Accepted: 09/15/2022] [Indexed: 06/15/2023]
Abstract
Monitoring renal allograft function after transplantation is key for the early detection of allograft impairment, which in turn can contribute to preventing the loss of the allograft. Multiparametric renal MRI (mpMRI) is a promising noninvasive technique to assess and characterize renal physiopathology; however, few studies have employed mpMRI in renal allografts with stable function (maintained function over a long time period). The purposes of the current study were to evaluate the reproducibility of mpMRI in transplant patients and to characterize normal values of the measured parameters, and to estimate the labeling efficiency of Pseudo-Continuous Arterial Spin Labeling (PCASL) in the infrarenal aorta using numerical simulations considering experimental measurements of aortic blood flow profiles. The subjects were 20 transplant patients with stable kidney function, maintained over 1 year. The MRI protocol consisted of PCASL, intravoxel incoherent motion, and T1 inversion recovery. Phase contrast was used to measure aortic blood flow. Renal blood flow (RBF), diffusion coefficient (D), pseudo-diffusion coefficient (D*), flowing fraction ( f ), and T1 maps were calculated and mean values were measured in the cortex and medulla. The labeling efficiency of PCASL was estimated from simulation of Bloch equations. Reproducibility was assessed with the within-subject coefficient of variation, intraclass correlation coefficient, and Bland-Altman analysis. Correlations were evaluated using the Pearson correlation coefficient. The significance level was p less than 0.05. Cortical reproducibility was very good for T1, D, and RBF, moderate for f , and low for D*, while medullary reproducibility was good for T1 and D. Significant correlations in the cortex between RBF and f (r = 0.66), RBF and eGFR (r = 0.64), and D* and eGFR (r = -0.57) were found. Normal values of the measured parameters employing the mpMRI protocol in kidney transplant patients with stable function were characterized and the results showed good reproducibility of the techniques.
Collapse
Affiliation(s)
- Rebeca Echeverria‐Chasco
- Department of RadiologyClínica Universidad de NavarraPamplonaSpain
- IdiSNA, Instituto de Investigación Sanitaria de NavarraPamplonaSpain
| | - Paloma L. Martin‐Moreno
- IdiSNA, Instituto de Investigación Sanitaria de NavarraPamplonaSpain
- Department of NephrologyClínica Universidad de NavarraPamplonaSpain
| | - Nuria Garcia‐Fernandez
- IdiSNA, Instituto de Investigación Sanitaria de NavarraPamplonaSpain
- Department of NephrologyClínica Universidad de NavarraPamplonaSpain
| | | | - Verónica Aramendia‐Vidaurreta
- Department of RadiologyClínica Universidad de NavarraPamplonaSpain
- IdiSNA, Instituto de Investigación Sanitaria de NavarraPamplonaSpain
| | - David Cano
- Department of RadiologyClínica Universidad de NavarraPamplonaSpain
| | - Arantxa Villanueva
- IdiSNA, Instituto de Investigación Sanitaria de NavarraPamplonaSpain
- Electrical Electronics and Communications Engineering Department and Smart Cities InstitutePublic University of NavarrePamplonaSpain
| | - Gorka Bastarrika
- Department of RadiologyClínica Universidad de NavarraPamplonaSpain
- IdiSNA, Instituto de Investigación Sanitaria de NavarraPamplonaSpain
| | - Maria A. Fernández‐Seara
- Department of RadiologyClínica Universidad de NavarraPamplonaSpain
- IdiSNA, Instituto de Investigación Sanitaria de NavarraPamplonaSpain
| |
Collapse
|
7
|
Edosuyi O, Adesuyi A, Choi M, Igbe I, Oyekan A. Malate reduced blood pressure and exerted differential effects on renal hemodynamics; role of the nitric oxide system and renal epithelial sodium channels (E NaC). Eur J Pharmacol 2023; 938:175441. [PMID: 36463945 PMCID: PMC9772084 DOI: 10.1016/j.ejphar.2022.175441] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 11/10/2022] [Accepted: 11/29/2022] [Indexed: 12/05/2022]
Abstract
Malate regulates blood pressure via nitric oxide production in salt-sensitive rats, a genetic model of hypertension. This study investigated the possible contributions of malate to blood pressure regulation and renal haemodynamics in normotensive rats. Malate (0.1, 0.3 and 1 μg/kg, iv) was injected into rats or L-nitro-arginine methyl ester (L-NAME)-treated rats and mean arterial blood pressure (MABP), cortical blood flow (CBF), and medullary blood flow (MBF), was measured. The clearance study involved infusion of malate at 0.1 μg/kg/h into rats, and MABP, CBF, MBF, glomerular filtration rate (GFR), urine volume (UV) and sodium output (UNaV) were determined. Mechanistic studies to evaluate the role of renal sodium channels involved the treatment with malate (600 mg/kg, po), amiloride (2.5 mg/kg, po) or hydrochlorothiazide (HCTZ) (10 mg/kg, po), and UV and UNaV were determined. Malate elicited significant peak reductions in MABP (124 ± 6.5 vs 105 ± 3.1 mmHg) at 0.1 μg/kg), CBF (231 ± 18.5 vs 205 ± 10.9 PU). L-NAME did not reverse the effect of malate on MABP but tended to blunt the effect on CBF (40%) and MBF (87%) at 0.3 μg/kg. Infusion of malate reduced MABP, CBF, and MBF in a time-dependent manner (p<0.05). Malate exerted a three-fold decrease in GFR in a time-related fashion (p<0.05) as well as increased UV. UNaV increased by 86% in malate-treated-amiloride rats (p<0.05). These data indicate that malate modulates blood pressure and exerts vascular and tubular effects on renal function that may involve epithelial sodium channels (ENaC).
Collapse
Affiliation(s)
- Osaze Edosuyi
- Department of Pharmacology & Toxicology, Faculty of Pharmacy, University of Benin, PMB 1154, Benin City, Nigeria; Center for Cardiovascular Diseases, Gray Hall Suites, Rm 256, College of Pharmacy & Health Sciences, Texas Southern University, 3100, Cleburne Street, Houston, TX, USA.
| | - Ayobami Adesuyi
- Department of Pharmacology & Toxicology, Faculty of Pharmacy, University of Benin, PMB 1154, Benin City, Nigeria; Community Medicine Department, Babcock University Teaching Hospital, IIishan-Remo, Ogun state, Nigeria
| | - Myung Choi
- Center for Cardiovascular Diseases, Gray Hall Suites, Rm 256, College of Pharmacy & Health Sciences, Texas Southern University, 3100, Cleburne Street, Houston, TX, USA
| | - Ighodaro Igbe
- Department of Pharmacology & Toxicology, Faculty of Pharmacy, University of Benin, PMB 1154, Benin City, Nigeria
| | - Adebayo Oyekan
- Center for Cardiovascular Diseases, Gray Hall Suites, Rm 256, College of Pharmacy & Health Sciences, Texas Southern University, 3100, Cleburne Street, Houston, TX, USA
| |
Collapse
|
8
|
van Ochten M, Westerhof BE, Spaanderman MEA, Antonius TAJ, van Drongelen J. Modeling renal autoregulation in a hemodynamic, first-trimester gestational model. Physiol Rep 2022; 10:e15484. [PMID: 36200318 PMCID: PMC9535437 DOI: 10.14814/phy2.15484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 09/13/2022] [Accepted: 09/14/2022] [Indexed: 11/06/2022] Open
Abstract
The maternal cardiovascular system, led by renal volume regulatory responses, changes during pregnancy to ensure an adequate circulation for fetal development and growth. Circulatory maladjustment predisposes to hypertensive complications during pregnancy. Mathematical models can be used to gain insight in the gestational cardiovascular physiology. In this study, we developed an accurate, robust, and transparent model for renal autoregulation implemented in an existing circulatory gestational model. This renal autoregulation model aims to maintain steady glomerular pressure by the myogenic response, and glomerular filtration rate by tubuloglomerular feedback, both by inducing a change in the radius, and thus resistance, of the afferent arteriole. The modeled response of renal blood flow and the afferent arteriole following blood pressure increase were compared to published observations in rats. With solely the myogenic response, our model had a maximum deviation of 7% in change in renal blood flow and 7% in renal vascular resistance. When both the myogenic response and tubuloglomerular feedback were concurrently activated, the maximum deviation was 7% in change in renal blood flow and 5% in renal vascular resistance. These results show that our model is able to represent renal autoregulatory behavior comparable to empirical data. Further studies should focus on extending the model with other regulatory mechanisms to understand the hemodynamic changes in healthy and complicated pregnancy.
Collapse
Affiliation(s)
- Maaike van Ochten
- Department of Gynecology and ObstetricsRadboud University Medical CenterNijmegenThe Netherlands
- Department of Gynecology and ObstetricsMaastricht University Medical CenterMaastrichtThe Netherlands
- Division of Neonatology, Department of PerinatologyRadboud University Medical Center, Radboud Institute for Health Sciences, Amalia Children's HospitalNijmegenThe Netherlands
| | - Berend E. Westerhof
- Division of Neonatology, Department of PerinatologyRadboud University Medical Center, Radboud Institute for Health Sciences, Amalia Children's HospitalNijmegenThe Netherlands
- Department of Pulmonary MedicineAmsterdam University Medical Centers, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular SciencesAmsterdamThe Netherlands
| | - Marc E. A. Spaanderman
- Department of Gynecology and ObstetricsRadboud University Medical CenterNijmegenThe Netherlands
- Department of Gynecology and ObstetricsMaastricht University Medical CenterMaastrichtThe Netherlands
| | - Tim A. J. Antonius
- Division of Neonatology, Department of PerinatologyRadboud University Medical Center, Radboud Institute for Health Sciences, Amalia Children's HospitalNijmegenThe Netherlands
| | - Joris van Drongelen
- Department of Gynecology and ObstetricsRadboud University Medical CenterNijmegenThe Netherlands
| |
Collapse
|
9
|
Rocha MP, Gliemann L. Exercise and the kidneys: How does renal blood flow behave when measured during exercise? Physiol Rep 2022; 10:e15485. [PMID: 36200293 PMCID: PMC9535345 DOI: 10.14814/phy2.15485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 09/16/2022] [Indexed: 06/16/2023] Open
Affiliation(s)
- Marcos Paulo Rocha
- The August Krogh Section for Human Physiology, Department of Nutrition, Exercise and SportsUniversity of CopenhagenCopenhagenDenmark
| | - Lasse Gliemann
- The August Krogh Section for Human Physiology, Department of Nutrition, Exercise and SportsUniversity of CopenhagenCopenhagenDenmark
| |
Collapse
|
10
|
Shimada S, Yang C, Kumar V, Mattson DL, Cowley AW. Acute Increase of Renal Perfusion Pressure Causes Rapid Activation of mTORC1 (Mechanistic Target Of Rapamycin Complex 1) and Leukocyte Infiltration. Hypertension 2022; 79:1180-1189. [PMID: 35291809 PMCID: PMC9098670 DOI: 10.1161/hypertensionaha.121.18643] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 02/25/2022] [Indexed: 11/16/2022]
Abstract
BACKGROUND The present study in Sprague-Dawley rats determined the effects of a rapid rise of renal perfusion pressure (RPP) upon the activation of mTOR (mechanistic target of rapamycin), and the effects upon the infiltration of CD68-positive macrophages/monocytes and CD3-positive T lymphocytes into the kidneys. METHODS RPP was elevated by 40 mm Hg for 30 minutes in male Sprague-Dawley rats while measuring renal blood flow and urine flow rate. Sham rats were studied in the same way, but RPP was not changed. Since initial studies found that the acute increase of RPP resulted in activation of mTORC1 (phosphorylation of S6S235/236), the effects of inhibition of mTORC1 with rapamycin pretreatment were then determined. RESULTS It was found that a 30-minute increase of RPP (≈40 mm Hg) resulted in an 8-fold increase of renal sodium excretion which was blunted by rapamycin treatment. Renal blood flow was not affected by the elevation of RPP. Activation of mTORC1 was observed. Significant increases in CD68-positive macrophages were found in both the cortex (intraglomerular and periglomerular regions) and in the outer medullary interstitial regions of the kidney and prevented by rapamycin treatment. Increases in CD3-positive T lymphocytes were observed exclusively in the periglomerular regions and prevented by rapamycin treatment. Upregulation of several proinflammatory markers was observed. CONCLUSIONS We conclude that elevation of RPP rapidly activates mTORC1 resulting in infiltration of immune cells into the kidney.
Collapse
Affiliation(s)
- Satoshi Shimada
- Department of Physiology, Medical College of Wisconsin, Milwaukee (S.S., C.Y., V.K., D.L.M., A.W.C.)
| | - Chun Yang
- Department of Physiology, Medical College of Wisconsin, Milwaukee (S.S., C.Y., V.K., D.L.M., A.W.C.)
| | - Vikash Kumar
- Department of Physiology, Medical College of Wisconsin, Milwaukee (S.S., C.Y., V.K., D.L.M., A.W.C.)
| | - David L Mattson
- Department of Physiology, Medical College of Wisconsin, Milwaukee (S.S., C.Y., V.K., D.L.M., A.W.C.)
- Now with: Department of Physiology, Medical College of Georgia at Augusta University (D.L.M.)
| | - Allen W Cowley
- Department of Physiology, Medical College of Wisconsin, Milwaukee (S.S., C.Y., V.K., D.L.M., A.W.C.)
| |
Collapse
|
11
|
McLarnon SR, Wilson K, Patel B, Sun J, Sartain CL, Mejias CD, Musall JB, Sullivan JC, Wei Q, Chen JK, Hyndman KA, Marshall B, Yang H, Fogo AB, O’Connor PM. Lipopolysaccharide Pretreatment Prevents Medullary Vascular Congestion following Renal Ischemia by Limiting Early Reperfusion of the Medullary Circulation. J Am Soc Nephrol 2022; 33:769-785. [PMID: 35115326 PMCID: PMC8970460 DOI: 10.1681/asn.2021081089] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 01/16/2022] [Indexed: 11/03/2022] Open
Abstract
BACKGROUND Vascular congestion of the renal medulla-trapped red blood cells in the medullary microvasculature-is a hallmark finding at autopsy in patients with ischemic acute tubular necrosis. Despite this, the pathogenesis of vascular congestion is not well defined. METHODS In this study, to investigate the pathogenesis of vascular congestion and its role in promoting renal injury, we assessed renal vascular congestion and tubular injury after ischemia reperfusion in rats pretreated with low-dose LPS or saline (control). We used laser Doppler flowmetry to determine whether pretreatment with low-dose LPS prevented vascular congestion by altering renal hemodynamics during reperfusion. RESULTS We found that vascular congestion originated during the ischemic period in the renal venous circulation. In control animals, the return of blood flow was followed by the development of congestion in the capillary plexus of the outer medulla and severe tubular injury early in reperfusion. Laser Doppler flowmetry indicated that blood flow returned rapidly to the medulla, several minutes before recovery of full cortical perfusion. In contrast, LPS pretreatment prevented both the formation of medullary congestion and its associated tubular injury. Laser Doppler flowmetry in LPS-pretreated rats suggested that limiting early reperfusion of the medulla facilitated this protective effect, because it allowed cortical perfusion to recover and clear congestion from the large cortical veins, which also drain the medulla. CONCLUSIONS Blockage of the renal venous vessels and a mismatch in the timing of cortical and medullary reperfusion results in congestion of the outer medulla's capillary plexus and promotes early tubular injury after renal ischemia. These findings indicate that hemodynamics during reperfusion contribute to the renal medulla's susceptibility to ischemic injury.
Collapse
Affiliation(s)
- Sarah R. McLarnon
- Department of Physiology, Medical College of Georgia at Augusta University, Augusta, Georgia
| | - Katie Wilson
- Department of Physiology, Medical College of Georgia at Augusta University, Augusta, Georgia
| | - Bansari Patel
- Department of Physiology, Medical College of Georgia at Augusta University, Augusta, Georgia
| | - Jingping Sun
- Department of Physiology, Medical College of Georgia at Augusta University, Augusta, Georgia
| | - Christina L. Sartain
- Department of Physiology, Medical College of Georgia at Augusta University, Augusta, Georgia
| | - Christopher D. Mejias
- Department of Physiology, Medical College of Georgia at Augusta University, Augusta, Georgia
| | - Jacqueline B. Musall
- Department of Physiology, Medical College of Georgia at Augusta University, Augusta, Georgia
| | - Jennifer C. Sullivan
- Department of Physiology, Medical College of Georgia at Augusta University, Augusta, Georgia
| | - Qingqing Wei
- Department of Cell Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, Georgia
| | - Jian-Kang Chen
- Department of Cell Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, Georgia
| | - Kelly A. Hyndman
- Cardio-Renal Physiology and Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Brendan Marshall
- Department of Cell Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, Georgia
| | - Haichun Yang
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Agnes B. Fogo
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Paul M. O’Connor
- Department of Physiology, Medical College of Georgia at Augusta University, Augusta, Georgia
| |
Collapse
|
12
|
Abstract
The kidneys play a crucial role in maintaining the homeostasis of body fluids. The regulation of renal blood flow (RBF) is essential to the vital functions of filtration and metabolism in kidney function. Many acute studies have been carried out in anesthetized animals to measure RBF under various conditions to determine mechanisms responsible for the regulation of kidney perfusion. However, for technical reasons, it has not been possible to measure RBF continuously (24 h/day) in unrestrained unanesthetized rats over prolonged periods. These methods allow the continuous determination of RBF over many weeks while also simultaneously recording blood pressure (BP) with implanted catheters (fluid-filled or by telemetry). RBF monitoring is carried out with rats placed in a circular servo-controlled rat cage that enables the unrestrained movement of the rat throughout the study. At the same time, the tangling of cables from the flow probe and arterial catheters is prevented. Rats are first instrumented with an ultrasonic flow probe placement on the left renal artery and an arterial catheter implanted in the right femoral artery. These are routed subcutaneously to the nape of the neck, and connected to the flowmeter and pressure transducer, respectively, to measure RBF and BP. Following surgical implantation, rats are immediately placed in the cage to recover for at least one week and stabilize the ultrasonic probe recordings. Urine collection is also feasible in this system. The surgical and post-surgical procedures for continuous monitoring are demonstrated in this protocol.
Collapse
|
13
|
Hayfron-Benjamin CF, van den Born BJ, Amoah AGB, Maitland-van der Zee AH, Meeks KAC, Beune EJAJ, Klipstein-Grobusch K, Agyemang C. Associations of Serum Uric Acid Levels With Macrovascular and Renal Microvascular Dysfunction Among Individuals From Sub-Saharan Africa. JAMA Netw Open 2021; 4:e2128985. [PMID: 34648008 PMCID: PMC8517747 DOI: 10.1001/jamanetworkopen.2021.28985] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
IMPORTANCE Serum uric acid (SUA) level is associated with vascular dysfunction in Eurasian populations, but little is known about this association in individuals from sub-Saharan Africa, who have a high prevalence of both relatively high SUA levels and vascular dysfunction. OBJECTIVES To assess the associations of SUA levels with macrovascular and kidney microvascular dysfunction in individuals of sub-Saharan African ancestry and evaluate potential factors that could mediate these associations. DESIGN, SETTING, AND PARTICIPANTS Cross-sectional analyses of baseline data from the multicenter Research on Obesity and Diabetes Among African Migrants study, conducted from 2012 to 2015, were performed from January to March 2021. The population included Ghanaian individuals living in Ghana and Europe. EXPOSURE Abnormal SUA levels. MAIN OUTCOMES AND MEASURES Logistic regression was used to examine the associations of SUA level quartiles with microvascular (albuminuria) and macrovascular (peripheral artery disease and coronary artery disease) dysfunction, with adjustments for age, sex, estimated glomerular filtration rate, site of residence, socioeconomic status, alcohol, smoking, diabetes, hypertension, waist-hip ratio, and total cholesterol level. Mediation analysis was performed to assess whether the association was via elevated blood pressure, hemoglobin A1c, and high-sensitivity C-reactive protein levels or via weight-hip ratio. The research questions were formulated after data collection. RESULTS A total of 4919 Ghanaian individuals (3047 [61.9%] women) aged 25-75 years (mean [SD], 46.26 [11.08] years) were included. There was a significant positive association between SUA quartiles and albuminuria, but not coronary artery disease or peripheral artery disease, after adjustment for covariates. After full adjustment, individuals in the fourth SUA quartile had higher odds of albuminuria (adjusted odds ratio [aOR], 1.54; 95% CI, 1.07-2.21), but not peripheral artery disease (aOR, 1.35; 95% CI, 0.87-2.08) or coronary artery disease (aOR, 1.09; 95% CI, 0.77-1.55), compared with individuals in the first quartile. After full adjustment, systolic and diastolic blood pressure significantly mediated the association between SUA concentrations and albuminuria, accounting for 19.4% of the total association for systolic and 17.2% for diastolic blood pressure; hemoglobin A1c, high-sensitivity C-reactive protein, and waist-hip ratio did not mediate this association. CONCLUSIONS AND RELEVANCE In this cross-sectional study among a sub-Saharan African population, elevated SUA levels were significantly associated with kidney microvascular dysfunction and mediated partly through elevated blood pressure. These findings suggest that individuals from sub-Saharan Africa with elevated SUA levels may benefit from periodic screening for kidney microvascular dysfunction to aid early detection or treatment.
Collapse
Affiliation(s)
- Charles F. Hayfron-Benjamin
- Department of Public Health, Amsterdam University Medical Centre (UMC), University of Amsterdam, Amsterdam Public Health Research Institute, Amsterdam, the Netherlands
- Department of Internal and Vascular Medicine, Amsterdam UMC, University of Amsterdam, Cardiovascular Sciences, Amsterdam, the Netherlands
- Department of Respiratory Medicine, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
- Department of Physiology, University of Ghana Medical School, Accra, Ghana
- Center for Research on Genomics and Global Health, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland
| | - Bert-Jan van den Born
- Department of Public Health, Amsterdam University Medical Centre (UMC), University of Amsterdam, Amsterdam Public Health Research Institute, Amsterdam, the Netherlands
- Department of Internal and Vascular Medicine, Amsterdam UMC, University of Amsterdam, Cardiovascular Sciences, Amsterdam, the Netherlands
| | - Albert G. B. Amoah
- Department of Medicine and Therapeutics, University of Ghana Medical School, Ghana
| | | | - Karlijn A. C. Meeks
- Department of Public Health, Amsterdam University Medical Centre (UMC), University of Amsterdam, Amsterdam Public Health Research Institute, Amsterdam, the Netherlands
- Department of Anaesthesia, Korle Bu Teaching Hospital, Accra, Ghana
| | - Erik J. A. J. Beune
- Department of Public Health, Amsterdam University Medical Centre (UMC), University of Amsterdam, Amsterdam Public Health Research Institute, Amsterdam, the Netherlands
| | - Kerstin Klipstein-Grobusch
- Julius Global Health, Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands
- Division of Epidemiology and Biostatistics, School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Charles Agyemang
- Department of Public Health, Amsterdam University Medical Centre (UMC), University of Amsterdam, Amsterdam Public Health Research Institute, Amsterdam, the Netherlands
| |
Collapse
|
14
|
Watchorn J, Huang DY, Joslin J, Bramham K, Hutchings SD. Critically Ill COVID-19 Patients With Acute Kidney Injury Have Reduced Renal Blood Flow and Perfusion Despite Preserved Cardiac Function: A Case-Control Study Using Contrast-Enhanced Ultrasound. Shock 2021; 55:479-487. [PMID: 32890313 DOI: 10.1097/shk.0000000000001659] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND Acute kidney injury (AKI) is a common complication of COVID-19 critical illness but the pathophysiology is uncertain. Some evidence has indicated that a vascular aetiology may be implicated. We used contrast-enhanced ultrasound (CEUS) and echocardiography to study renal perfusion and global blood flow and compared our findings with measurements taken in a group of septic shock patients and healthy volunteers. METHODS Prospective case-control study. Renal perfusion variables were assessed with CEUS; macrovascular blood flow was assessed using Doppler analysis of large renal vessels; echocardiography was used to assess right and left heart function and cardiac output. RESULTS CEUS-derived parameters were reduced in COVID-19 associated AKI compared with healthy controls (perfusion index 3,415 vs. 548 a.u., P = 0·001; renal blood volume 7,794 vs. 3,338 a.u., P = 0·04). Renal arterial flow quantified using time averaged peak velocity was also reduced compared with healthy controls (36·6 cm/s vs. 20·9 cm/s, P = 0.004) despite cardiac index being similar between groups (2.8 L/min/m2 vs. 3.7 L/min/m2, P = 0.07). There were no differences in CEUS-derived or cardiac parameters between COVID-19 and septic shock patients but patients with septic shock had more heterogeneous perfusion variables. CONCLUSION Both large and small vessel blood flow is reduced in patients with COVID-19 associated AKI compared with healthy controls, which does not appear to be a consequence of right or left heart dysfunction. A reno-vascular pathogenesis of COVID-19 AKI seems likely.
Collapse
Affiliation(s)
- James Watchorn
- School of Immunology and Microbial Sciences, Faculty of Life Sciences and Medicine, King's College London, London, UK
- Academic Department of Military Anaesthesia and Critical Care, Royal Centre for Defence Medicine, Birmingham, UK
| | - Dean Y Huang
- King's College Hospital NHS Foundation Trust, London, UK
| | - Jennifer Joslin
- School of Immunology and Microbial Sciences, Faculty of Life Sciences and Medicine, King's College London, London, UK
| | - Kate Bramham
- King's College Hospital NHS Foundation Trust, London, UK
- School of Life Course Sciences, King's College London, London, UK
| | - Sam D Hutchings
- School of Immunology and Microbial Sciences, Faculty of Life Sciences and Medicine, King's College London, London, UK
- Academic Department of Military Anaesthesia and Critical Care, Royal Centre for Defence Medicine, Birmingham, UK
- King's College Hospital NHS Foundation Trust, London, UK
| |
Collapse
|
15
|
Abstract
PURPOSE OF REVIEW Many forms of acute and chronic disease are linked to changes in renal blood flow, perfusion, vascular density and hypoxia, but there are no readily available methods to assess these parameters in clinical practice. Dynamic contrast enhanced ultrasound (DCE-US) is a method that provides quantitative assessments of organ perfusion without ionising radiation or risk of nephrotoxicity. It can be performed at the bedside and is suitable for repeated measurements. The purpose of this review is to provide updates from recent publications on the utility of DCE-US in the diagnosis or assessment of renal disease, excluding the evaluation of benign or malignant renal masses. RECENT FINDINGS DCE-US has been applied in clinical studies of acute kidney injury (AKI), renal transplantation, chronic kidney disease (CKD), diabetic kidney disease and to determine acute effects of pharmacological agents on renal haemodynamics. DCE-US can detect changes in renal perfusion across these clinical scenarios and can differentiate healthy controls from those with CKD. In sepsis, reduced DCE-US measures of perfusion may indicate those at increased risk of developing AKI, but this requires confirmation in larger studies as there can be wide individual variation in perfusion measures in acutely unwell patients. Recent studies in transplantation have not provided robust evidence to show that DCE-US can differentiate between different causes of graft dysfunction, although it may show more promise as a prognostic indicator of graft function 1 year after transplant. DCE-US can detect acute haemodynamic changes in response to medication that correlate with changes in renal plasma flow as measured by para-aminohippurate clearance. SUMMARY DCE-US shows promise and has a number of advantages that make it suitable for the assessment of patients with various forms of kidney disease. However, further research is required to evidence its reproducibility and utility before clinical use can be advocated.
Collapse
Affiliation(s)
- Nicholas M Selby
- Division of Medical Sciences and Graduate Entry Medicine, Centre for Kidney Research and Innovation, University of Nottingham, Royal Derby Hospital Centre
- Department of Renal Medicine, Royal Derby Hospital
| | - John P Williams
- Division of Medical Sciences and Graduate Entry Medicine, MRC-Versus Arthritis Centre for Musculoskeletal Ageing Research and Nottingham Biomedical Research Centre, University of Nottingham, Royal Derby Hospital Centre
- Department of Anaesthesia and Critical Care, Royal Derby Hospital, Derby, UK
| | - Bethan E Phillips
- Division of Medical Sciences and Graduate Entry Medicine, MRC-Versus Arthritis Centre for Musculoskeletal Ageing Research and Nottingham Biomedical Research Centre, University of Nottingham, Royal Derby Hospital Centre
| |
Collapse
|
16
|
Stritzke A. Renal Arterial Doppler Perfusion Pattern with and without Ductal Steal. J Pediatr 2020; 223:225-226. [PMID: 32376259 DOI: 10.1016/j.jpeds.2020.04.061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 04/24/2020] [Indexed: 11/19/2022]
Affiliation(s)
- Amelie Stritzke
- Department of Pediatrics, Section of Neonatology, University of Calgary, Cumming School of Medicine, Libin Cardiovascular Institute of Alberta, Foothills Medical Center, Calgary, Alberta, Canada
| |
Collapse
|
17
|
Candan Y, Akinci M, Eraslan O, Yilmaz KB, Karabacak H, Dural HI, Tatar IG, Kaya IO. The Correlation of Intraabdominal Pressure With Renal Resistive Index. J Surg Res 2020; 252:240-246. [PMID: 32304930 DOI: 10.1016/j.jss.2020.03.024] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Revised: 03/01/2020] [Accepted: 03/09/2020] [Indexed: 01/15/2023]
Abstract
BACKGROUND To evaluate the correlation between intraabdominal pressure (IAP) measured via the bladder and renal resistive index (RRI) measured by Doppler ultrasonography (USG). METHODS Eighty consecutive surgical patients were included into this study. Before Doppler USG evaluation, IAP was measured by a Foley catheter via the bladder. The left and right RRI, the diameters of the inferior vena cava and portal vein were measured by colored Doppler USG. Spearman correlation analysis was used to evaluate the correlation between different measurements. Intraabdominal hypertension (IAH) was defined as of IAP ≥ 12 mmHg. Significantly different variables from the univariate analysis between patients with and without IAH were entered into backward stepwise binary logistic regression analysis of IAH as the dependent variable. P values < 0.05 were accepted as statistically significant. RESULTS In total, 80 patients were included into study. In 27 patients (34%) IAP was normal and in 53 patients (66%) IAH was diagnosed. The Spearman correlation analysis of IAP and the ultrasonographic measurements revealed a strong correlation between RRI and IAP (P < 0.001). Patients with IAH were more likely to be diabetic and had abdominal incisional hernia compared with patients with normal IAP (P < 0.05). The results of the multivariate logistic regression analysis revealed right RRI as the only independent predictor of IAH (B: 57.04, S. E.: 13.7, P < 0.001). CONCLUSIONS There is a strong correlation between IAP and RRI. RRI can be an alternative, noninvasive technique for the diagnosis and follow-up of IAH after further evaluations in different patient groups.
Collapse
Affiliation(s)
- Yeliz Candan
- Department of Surgery, University of Health Sciences, Ankara Diskapi Teaching and Research Hospital, Ankara, Turkey
| | - Melih Akinci
- Department of Surgery, University of Health Sciences, Gulhane Teaching and Research Hospital, Ankara, Turkey.
| | - Onder Eraslan
- Department of Radiology, Tokat Erbaa Ministry of Health State Hospital, Tokat, Turkey
| | - Kerim Bora Yilmaz
- Department of Surgery, University of Health Sciences, Gulhane Teaching and Research Hospital, Ankara, Turkey
| | - Harun Karabacak
- Department of Surgery, University of Health Sciences, Ankara Diskapi Teaching and Research Hospital, Ankara, Turkey
| | - Halil Ibrahim Dural
- Department of Surgery, University of Health Sciences, Ankara Diskapi Teaching and Research Hospital, Ankara, Turkey
| | - Idil Gunes Tatar
- Department of Radiology, University of Health Sciences, Ankara Diskapi Teaching and Research Hospital, Ankara, Turkey
| | - Ismail Oskay Kaya
- Department of Surgery, University of Health Sciences, Ankara Diskapi Teaching and Research Hospital, Ankara, Turkey
| |
Collapse
|
18
|
Asbeutah AM, Adekile A, AlMajran AA, Asbeutah AAA, Naief AA, Al-Jafar H. Pattern of Renal Blood Flow and Renovascular Parameters in Adult Patients With Sickle Cell Disease. J Ultrasound Med 2020; 39:785-793. [PMID: 31663639 DOI: 10.1002/jum.15158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 09/12/2019] [Accepted: 09/29/2019] [Indexed: 06/10/2023]
Abstract
OBJECTIVES To evaluate renal blood flow patterns and renovascular parameters in adult patients with sickle cell disease (SCD) without laboratory evidence of renal impairment. METHODS Sixty-five steady-state adult patients with SCD (50 hemoglobin SS [HbSS], 12 HbSβ0 , and 3 HbSD) and 30 age- and sex-matched healthy controls were studied. The kidney length, echo pattern, peak systolic velocity (PSV), end-diastolic velocity, renal-to-aortic ratio, resistive index (RI), acceleration time (AT), and renal vein velocity were acquired, recorded, and analyzed with a 1-5-MHz curvilinear transducer through the abdomen. RESULTS The mean age ± SD of the patients with SCD was 32.89 ± 13.89 years. The highest means for the ultrasound-measured renal length and cortical thickness in the SCD and control groups were 11.78 ± 1.30 and 11.27 ± 0.77 cm and 1.86 ± 0.41 and 1.78 ± 0.28 cm, respectively. The figures were significantly higher in the SCD group than the control group (P < .05). Fifty-nine (90.8%) patients had a mild diffuse increase in cortical echogenicity with preserved renal cortical thickness. The highest mean extrarenal PSVs in the SCD and control groups were 138.46 ± 56.32 and 101.75 ± 31.48 cm/s (P < .05). However, the highest intrarenal RI and AT in SCD and control groups were 0.69 ± 0.07 and 0.06 ± 0.02 seconds and 0.63 ± 0.05 and 0.04 ± 0.01 seconds (P < .05). There was no significant correlation between the RI, AT, and PSV among the patients with SCD (P > .05). CONCLUSIONS Increased renal length and cortical echogenicity with elevated PSV, RI, and AT values can serve as early ultrasound changes in adult patients with SCD without renal impairment.
Collapse
Affiliation(s)
- Akram M Asbeutah
- Department of Radiologic Sciences, Faculty of Allied Health Sciences, Kuwait University, Sulaibekhat, Kuwait
- Department of Clinical Radiology, Al-Sabah Hospital, Ministry of Health, Sulaibekhat, Kuwait
- Department of Hematology, Al-Amiri Hospital, Ministry of Health, Sulaibekhat, Kuwait
| | - Adekunle Adekile
- Departments of Pediatrics, Faculty of Medicine, Kuwait University, Safat, Kuwait
| | - Abdullah A AlMajran
- Community Medicine and Behavioral Sciences, Faculty of Medicine, Kuwait University, Safat, Kuwait
| | - Abdul Aziz A Asbeutah
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA
| | - Athbi A Naief
- Department of Clinical Radiology, Al-Sabah Hospital, Ministry of Health, Sulaibekhat, Kuwait
| | - Hassan Al-Jafar
- Department of Radiologic Sciences, Faculty of Allied Health Sciences, Kuwait University, Sulaibekhat, Kuwait
- Department of Hematology, Al-Amiri Hospital, Ministry of Health, Sulaibekhat, Kuwait
| |
Collapse
|
19
|
Abstract
Impaired renal autoregulation permits more transmission of disturbance in systemic blood pressure, which initiates barotrauma in intrarenal microvasculatures such as glomerular and tubulointerstitial capillaries, contributing to the development of kidney damage and deterioration in renal function, especially under the conditions with high blood pressure. Although it has been postulated that autoregulatory efficiency is attenuated in the aging kidney, direct evidence remains lacking. In the present study, we measured the autoregulation of renal blood flow, myogenic response of afferent arteriole (Af-Art), tubuloglomerular feedback in vivo with micropuncture, as well as tubuloglomerular feedback in vitro in isolated perfused juxtaglomerular apparatus in young and aged C57BL/6 mice. We found that renal blood flow was not significantly changed in response to a defined elevation of renal arterial pressure in young mice but significantly increased in aged mice. Additionally, myogenic response of Af-Art measured by microperfusion with a stepwise increase in perfusion pressure was significantly blunted in the aging kidney, which is associated with the attenuation of intraluminal pressure-induced intracellular calcium increases, as well as the reduced expression of integrin α5 (Itga5) in Af-Art. Moreover, both tubuloglomerular feedback in vivo and in vitro were nearly inactive in the aging kidney, which is associated with the significantly reduced expression of adenosine A1 receptor (A1AR) and suppressed vasoconstrictor response to adenosine in Af-Art. In conclusion, this study demonstrates that aging impairs renal autoregulation with blunted myogenic response and inhibited tubuloglomerular feedback response. The underlying mechanisms involve the downregulations of integrin α5 and A1AR in the Af-Art.
Collapse
Affiliation(s)
- Jin Wei
- Department of Molecular Pharmacology & Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - Jinxiu Zhu
- The first affiliated hospital of Shantou University Medical College, Shantou, Guangdong, China
| | - Jie Zhang
- Department of Molecular Pharmacology & Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - Shan Jiang
- Department of Molecular Pharmacology & Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - Larry Qu
- Department of Molecular Pharmacology & Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - Lei Wang
- Department of Molecular Pharmacology & Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - Jacentha Buggs
- Advanced Organ Disease & Transplantation Institute, Tampa General Hospital, Tampa, Florida
| | - Xuerui Tan
- The first affiliated hospital of Shantou University Medical College, Shantou, Guangdong, China
| | - Feng Cheng
- Department of Pharmaceutical Science, College of Pharmacy, University of South Florida, Tampa, Florida
| | - Ruisheng Liu
- Department of Molecular Pharmacology & Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida
| |
Collapse
|
20
|
Watanabe I, Shintani Y, Terada S, Fujii T, Kiuchi S, Nakanishi R, Katayanagi T, Kawasaki M, Tokuhiro K, Ohsawa H, Ikeda T. A Clinical Association between an Increasing Renal Resistive Index and the Atherosclerotic Burden in Patients with a Preserved Renal Function. Intern Med 2020; 59:909-916. [PMID: 32238661 PMCID: PMC7184073 DOI: 10.2169/internalmedicine.3232-19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Objective A positive correlation is observed between the progression of renal impairment and the increasing risk of cardiovascular disease. Our aim was to examine the relationship between the renal resistive index (RRI) assessed by duplex sonography and the extent of atherosclerosis in patients without renal impairment undergoing vascular imaging studies. Methods The RRI was evaluated pre-procedurally among 106 outpatients with an estimated glomerular filtration rate (eGFR) ≥60 mL/min/1.73 m2 undergoing clinically-driven coronary computed tomography angiography (CCTA). In those subjects, a carotid artery ultrasound scan was also performed to evaluate carotid artery disease. We investigated the association between the RRI and the atherosclerotic extent, defined by the presence of coronary artery calcium (CAC) >0 and carotid intima-media thickness (cIMT) ≥1.0 mm. Results Multi-site atherosclerosis (CAC>0 and cIMT≥1.0 mm) was found in 31 patients. The RRI was significantly increased with an increasing number of atherosclerotic vessels (absence of atherosclerosis: 0.65±0.04 vs. single-site atherosclerosis: 0.67±0.06 vs. multi-site atherosclerosis: 0.71±0.05, p<0.001). A multivariate logistic regression analysis showed that RRI>0.70 [odds ratio (OR): 4.05, 95% confidence interval (CI), 1.37-12.0, p=0.01], cardio ankle vascular index (CAVI) ≥9.0 (OR: 8.18, 95% CI: 2.47-27.1, p<0.01), diabetes (OR: 4.34, 95% CI: 1.37-13.7, p=0.01) and an eGFR>90 mL/min/1.73 m2 (OR: 5.89, 95% CI: 1.39-25.1, p=0.01) were associated with multi-site atherosclerosis. Conclusion The RRI, a sub-clinical renal parameter is an atherosclerotic marker in patients without renal impairment.
Collapse
Affiliation(s)
- Ippei Watanabe
- Department of Cardiovascular Medicine, Toho University School of Medicine, Japan
| | - Yodo Shintani
- Cardiovascular Centre of Misato Central General Hospital, Japan
| | | | - Takahiro Fujii
- Department of Cardiovascular Medicine, Toho University School of Medicine, Japan
| | - Shunsuke Kiuchi
- Department of Cardiovascular Medicine, Toho University School of Medicine, Japan
| | - Rine Nakanishi
- Department of Cardiovascular Medicine, Toho University School of Medicine, Japan
| | | | | | | | - Hidefumi Ohsawa
- Cardiovascular Centre of Misato Central General Hospital, Japan
| | - Takanori Ikeda
- Department of Cardiovascular Medicine, Toho University School of Medicine, Japan
| |
Collapse
|
21
|
de Freitas Junior S, Bustorff-Silva JM, Ramos CD, Brunetto SQ, da Costa APM, Antunes AG, Biavatti BBV, Franchi Junior GC, Moreira MM, Felix PCG, Miranda ML. Scintigraphic Evaluation of the Impact of Pneumoperitoneum on Renal Blood Flow: A Rabbit Model. J Laparoendosc Adv Surg Tech A 2019; 29:1271-1275. [PMID: 31483185 DOI: 10.1089/lap.2019.0194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Background: Increased intra-abdominal pressure resulting from pneumoperitoneum can cause renal physiological changes, such as oliguria and anuria, in mammals. Although videolaparoscopic operations are common, the occurrence of renal lesions due to these procedures has not been precisely documented in the literature. The aim of this study was to evaluate the impact of pneumoperitoneum on renal blood flow using renal scintigraphy in a rabbit model. Methods: Six New Zealand male rabbits weighing 3 kg, previously anesthetized, were mechanically ventilated and underwent pneumoperitoneum. Each animal served as its own control and was analyzed in two different moments: [99mTc] diethylenetriaminepentaacetic acid (DTPA) renal blood flow evaluation in baseline conditions (T0) and 30 minutes after installation of 15 mmHg-pneumoperitoneum (T1). The animals were monitored throughout the study by capnography, oximetry, and arterial pressure median, and were euthanized at the end of the experiment. Results: The quantitative analysis of the scintigraphic images of renal uptake of the radiopharmaceutical evidence reduced renal arterial blood flow during pneumoperitoneum. Compared with baseline conditions, all animals presented a reduction of renal blood flow varying from 16% to 82%, with mean [±standard deviation] of 53% [±24%]. Conclusions: Pneumoperitoneum induces a significant reduction of the renal blood flow, as determined in this experimental method in rabbits and dynamic renal scintigraphy with [99mTc] DTPA is an adequate method to investigate this event in the experimental setting.
Collapse
Affiliation(s)
| | | | - Celso Dario Ramos
- Department of Radiology, State University of Campinas, Campinas, Brazil
| | | | | | | | | | | | | | | | | |
Collapse
|
22
|
Abe M, Akaishi T, Miki T, Miki M, Funamizu Y, Araya K, Ishizawa K, Takayama S, Takase K, Abe T, Ishii T, Ito S. Influence of renal function and demographic data on intrarenal Doppler ultrasonography. PLoS One 2019; 14:e0221244. [PMID: 31454365 PMCID: PMC6711528 DOI: 10.1371/journal.pone.0221244] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2019] [Accepted: 08/02/2019] [Indexed: 02/04/2023] Open
Abstract
Intrarenal Doppler ultrasonography is a non-invasive method to evaluate the renal blood flow in patients with renal arterial stenosis as well as chronic kidney diseases (CKD). Until recently, the relationship between ultrasonography findings and CKD stage has not been fully understood. Overall, 162 patients with CKD without apparent renal arterial stenosis were included in this study, and the pulsed-wave Doppler ultrasonography findings were evaluated in terms of the following parameters: peak systolic velocity (PSV), end-diastolic velocity (EDV), and resistive index (RI) at the renal arterial trunk, hilum, segmental, and interlobar regions. Age showed a significant negative correlation with the estimated glomerular filtration rate (eGFR), kidney size, and aortic PSV. Additionally, age showed a significant positive correlation with RI in all 4 regions. The eGFR showed a positive correlation with the aortic PSV and kidney size, but a negative correlation with RI. Both age and eGFR were found to be independently associated with aortic blood flow. On the intrarenal ultrasound, EDV and RI showed stronger correlations with eGFR than PSV, suggesting that the former indices would be better markers of renal function. In particular, the interlobar EDV was found to be the best index that reflects renal function. Although the RI is also a good marker of renal function, it is confounded by age; thus, its utility would be weaker than that of the EDV. In conclusion, intrarenal pulsed-wave Doppler ultrasonography is a useful tool to estimate and evaluate the renal function; the interlobar EDV may be the best index to estimate the effective perfusion and filtration of the kidneys.
Collapse
Affiliation(s)
- Michiaki Abe
- Department of Education and Support for Regional Medicine, Tohoku University Hospital, Sendai, Japan
- Department of Nephrology, Endocrinology and Vascular Medicine, Tohoku University Hospital, Sendai, Japan
- * E-mail:
| | - Tetsuya Akaishi
- Department of Education and Support for Regional Medicine, Tohoku University Hospital, Sendai, Japan
| | - Takashi Miki
- Clinical Physiology Center, Tohoku University Hospital, Sendai, Japan
| | - Mika Miki
- Clinical Physiology Center, Tohoku University Hospital, Sendai, Japan
| | - Yasuharu Funamizu
- Clinical Physiology Center, Tohoku University Hospital, Sendai, Japan
| | - Kaori Araya
- Clinical Physiology Center, Tohoku University Hospital, Sendai, Japan
| | - Kota Ishizawa
- Department of Education and Support for Regional Medicine, Tohoku University Hospital, Sendai, Japan
| | - Shin Takayama
- Department of Education and Support for Regional Medicine, Tohoku University Hospital, Sendai, Japan
| | - Kei Takase
- Diagnostic Radiology, Tohoku University Hospital, Sendai, Japan
| | - Takaaki Abe
- Department of Nephrology, Endocrinology and Vascular Medicine, Tohoku University Hospital, Sendai, Japan
| | - Tadashi Ishii
- Department of Education and Support for Regional Medicine, Tohoku University Hospital, Sendai, Japan
| | - Sadayoshi Ito
- Department of Nephrology, Endocrinology and Vascular Medicine, Tohoku University Hospital, Sendai, Japan
| |
Collapse
|
23
|
Bjornstad P, Lovshin JA, Lytvyn Y, Lovblom LE, Scarr D, Boulet G, Farooqi MA, Orszag A, Bai JW, Weisman A, Keenan HA, Brent MH, Paul N, Bril V, Perkins BA, Cherney DZI. Elevated plasma cyclic guanosine monophosphate may explain greater efferent arteriolar tone in adults with longstanding type 1 diabetes: A brief report. J Diabetes Complications 2019; 33:547-549. [PMID: 31186164 PMCID: PMC6613990 DOI: 10.1016/j.jdiacomp.2019.05.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Revised: 05/11/2019] [Accepted: 05/11/2019] [Indexed: 02/02/2023]
Abstract
Cyclic guanosine monophosphate (cGMP) influences intrarenal hemodynamics in animal models, but the relationship between cGMP and renal function in adults with type 1 diabetes (T1D) remains unclear. In this study, plasma cGMP correlated with efferent arteriolar resistance, effective renal plasma flow, and renal vascular resistance in adults with T1D.
Collapse
Affiliation(s)
- Petter Bjornstad
- Division of Endocrinology, Department of Pediatrics, University of Colorado, Aurora, CO, USA; Division of Nephrology, Department of Medicine, University of Colorado, Aurora, CO, USA.
| | - Julie A Lovshin
- Division of Endocrinology and Metabolism, Department of Medicine, University of Toronto, Toronto, ON, Canada; Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, ON, Canada
| | - Yuliya Lytvyn
- Division of Nephrology, Department of Medicine, University of Toronto, Toronto, ON, Canada
| | - Leif E Lovblom
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada
| | - Daniel Scarr
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada
| | - Geneviève Boulet
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada
| | - Mohammed A Farooqi
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada
| | - Andrej Orszag
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada
| | - Johnny-Wei Bai
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada
| | - Alanna Weisman
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada
| | | | - Michael H Brent
- Department of Ophthalmology and Vision Sciences, Department of Medicine, University of Toronto, Toronto, ON, Canada
| | - Narinder Paul
- Joint Department of Medical Imaging, Division of Cardiothoracic Radiology, University Health Network, Toronto, ON, Canada
| | - Vera Bril
- The Ellen and Martin Prosserman Centre for Neuromuscular Diseases, Krembil Neuroscience Centre, Division of Neurology, Department of Medicine, University Health Network, University of Toronto, Toronto, ON, Canada
| | - Bruce A Perkins
- Division of Endocrinology and Metabolism, Department of Medicine, University of Toronto, Toronto, ON, Canada; Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada
| | - David Z I Cherney
- Division of Nephrology, Department of Medicine, University of Toronto, Toronto, ON, Canada
| |
Collapse
|
24
|
Jiang K, Ferguson CM, Abumoawad A, Saad A, Textor SC, Lerman LO. A modified two-compartment model for measurement of renal function using dynamic contrast-enhanced computed tomography. PLoS One 2019; 14:e0219605. [PMID: 31291361 PMCID: PMC6619810 DOI: 10.1371/journal.pone.0219605] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 06/27/2019] [Indexed: 12/14/2022] Open
Abstract
Objectives To validate and adapt a modified two-compartment model, originally developed for magnetic resonance imaging, for measuring human single-kidney glomerular filtration rate (GFR) and perfusion using dynamic contrast-enhanced computed tomography (DCE-CT). Methods This prospective study was approved by the institutional review board, and written informed consent was obtained from all patients. Thirty-eight patients with essential hypertension (EH, n = 13) or atherosclerotic renal artery stenosis (ARAS, n = 25) underwent renal DCE-CT for GFR and perfusion measurement using a modified two-compartment model. Iothalamate clearance was used to measure reference total GFR, which was apportioned into single-kidney GFR by renal blood flow. Renal perfusion was also calculated using a conventional deconvolution algorithm. Validation of GFR and perfusion and inter-observer reproducibility, were conducted by using the Pearson correlation and Bland-Altman analysis. Results Both the two-compartment model and iothalamate clearance detected in ARAS patients lower GFR in the stenotic compared to the contralateral and EH kidneys. GFRs measured by DCE-CT and iothalamate clearance showed a close match (r = 0.94, P<0.001, and mean difference 2.5±12.2mL/min). Inter-observer bias and variation in model-derived GFR (r = 0.97, P<0.001; mean difference, 0.3±7.7mL/min) were minimal. Renal perfusion by deconvolution agreed well with that by the compartment model when the blood transit delay from abdominal aorta to kidney was negligible. Conclusion The proposed two-compartment model faithfully depicts contrast dynamics using DCE-CT and may provide a reliable tool for measuring human single-kidney GFR and perfusion.
Collapse
Affiliation(s)
- Kai Jiang
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Christopher M. Ferguson
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Abdelrhman Abumoawad
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Ahmed Saad
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Stephen C. Textor
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Lilach O. Lerman
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, United States of America
- * E-mail:
| |
Collapse
|
25
|
Zhang H, Xing X, Wang Z, He M. Evaluation of Split Renal Function for Children with Kidney Diseases by Renal and Vascular Color Ultrasonography. Ultrasound Med Biol 2018; 44:2602-2608. [PMID: 30185386 DOI: 10.1016/j.ultrasmedbio.2018.07.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 07/17/2018] [Accepted: 07/23/2018] [Indexed: 06/08/2023]
Abstract
Renal dynamic imaging and radionuclide renography use radioactivity to evaluate split renal function. We aimed to investigate the use of renal vascular color Doppler ultrasonography for evaluation of split renal function in children. Thirty-five children with unilateral kidney diseases were enrolled. For patients with unilateral renal tumor, peak systolic velocity (Vmax = 113.04 ± 13.59 cm/s) and resistance index (RI = 0.73 ± 0.02) were higher on abnormal compared with normal sides (Vmax = 86.03 ± 6.49 cm/s, RI = 0.62 ± 0.01), and blood perfusion was good, indicating compensatory enhancement in split renal function. For unilateral renal cyst, Vmax (58.20 ± 7.38 cm/s) was lower on the abnormal compared with the normal (87.71 ± 14.83 cm/s) size, and perfusion was poor. For unilateral hydronephrosis and renal atrophy, the parameters were similar to those of renal cyst, suggesting a weakening of renal function. For unilateral renal agenesis, Vmax (106.07 ± 13.07 cm/s) and RI (0.71 ± 0.05) were higher, and perfusion was good. Renal vascular color Doppler ultrasonography was superior in the evaluation of split renal function in children, without being invasive or radioactive.
Collapse
Affiliation(s)
- Hui Zhang
- Department of Pediatrics, West China Second University Hospital of Sichuan University, Chengdu, China; Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, Chengdu, China.
| | - Xuexue Xing
- Jinan Central Hospital Affiliated to Shandong University, Jinan, China
| | - Zheng Wang
- Department of Pediatrics, West China Second University Hospital of Sichuan University, Chengdu, China
| | - Min He
- Ultrasonic Department, West China Second University Hospital of Sichuan University, Chengdu, China
| |
Collapse
|
26
|
Kishino T, Harashima K, Hashimoto S, Fukuta N, Seki M, Ohnishi H, Watanabe T, Otaki J. Meal Ingestion and Hemodynamic Interactions Regarding Renal Blood Flow on Duplex Sonography: Potential Diagnostic Implications. Ultrasound Med Biol 2018; 44:2050-2054. [PMID: 30041904 DOI: 10.1016/j.ultrasmedbio.2018.05.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 05/13/2018] [Accepted: 05/16/2018] [Indexed: 06/08/2023]
Abstract
Splanchnic blood flow changes dramatically after meal ingestion. The present study evaluated physiologic interactions between meal ingestion and hemodynamics with respect to renal blood flow on duplex sonography, assessing the possible influence on Doppler parameters used as diagnostic criteria for renal artery stenosis. Subjects comprised 26 healthy young men (mean age: 22 ± 2 y). Sonographic measurements were made shortly after breakfast and every 1 h thereafter and were compared with values measured before the meal. Peak systolic velocity in the renal artery was elevated post-prandially, peaking at 1 h (90 ± 12 cm/s), compared with pre-prandially (73 ± 10 cm/s, p < 0.01). Similarly, acceleration time at the intra-renal segmental artery shortened to a minimum at 1 h (45 ± 5 ms) compared with baseline (51 ± 6 ms, p < 0.01). The present study indicates that renal blood flow is altered for a few hours after meal ingestion. Attention should be paid to the interpretation of data measured after meals on duplex sonography for diagnosis of renal artery stenosis.
Collapse
Affiliation(s)
- Tomonori Kishino
- Faculty of Health Sciences, Kyorin University, Tokyo, Japan; School of Medicine, Kyorin University, Tokyo, Japan.
| | | | | | - Naoya Fukuta
- Faculty of Health Sciences, Kyorin University, Tokyo, Japan
| | - Masayo Seki
- Faculty of Health Sciences, Kyorin University, Tokyo, Japan
| | | | | | - Junichi Otaki
- Faculty of Health Sciences, Kyorin University, Tokyo, Japan
| |
Collapse
|
27
|
Odudu A, Nery F, Harteveld AA, Evans RG, Pendse D, Buchanan CE, Francis ST, Fernández-Seara MA. Arterial spin labelling MRI to measure renal perfusion: a systematic review and statement paper. Nephrol Dial Transplant 2018; 33:ii15-ii21. [PMID: 30137581 PMCID: PMC6106644 DOI: 10.1093/ndt/gfy180] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 05/15/2018] [Indexed: 01/03/2023] Open
Abstract
Renal perfusion provides the driving pressure for glomerular filtration and delivers the oxygen and nutrients to fuel solute reabsorption. Renal ischaemia is a major mechanism in acute kidney injury and may promote the progression of chronic kidney disease. Thus, quantifying renal tissue perfusion is critically important for both clinicians and physiologists. Current reference techniques for assessing renal tissue perfusion have significant limitations. Arterial spin labelling (ASL) is a magnetic resonance imaging (MRI) technique that uses magnetic labelling of water in arterial blood as an endogenous tracer to generate maps of absolute regional perfusion without requiring exogenous contrast. The technique holds enormous potential for clinical use but remains restricted to research settings. This statement paper from the PARENCHIMA network briefly outlines the ASL technique and reviews renal perfusion data in 53 studies published in English through January 2018. Renal perfusion by ASL has been validated against reference methods and has good reproducibility. Renal perfusion by ASL reduces with age and excretory function. Technical advancements mean that a renal ASL study can acquire a whole kidney perfusion measurement in less than 5-10 min. The short acquisition time permits combination with other MRI techniques that might inform drug mechanisms and renal physiology. The flexibility of renal ASL has yielded several variants of the technique, but there are limited data comparing these approaches. We make recommendations for acquiring and reporting renal ASL data and outline the knowledge gaps that future research should address.
Collapse
Affiliation(s)
- Aghogho Odudu
- Division of Cardiovascular Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Fabio Nery
- Developmental Imaging & Biophysics Section, University College London, Great Ormond Street Institute of Child Health, London, UK
| | - Anita A Harteveld
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Roger G Evans
- Department of Physiology, Cardiovascular Disease Program, Biomedicine Discovery Institute, Monash University, Melbourne, Victoria, Australia
| | - Douglas Pendse
- Centre for Medical Imaging, University College London, London, UK
| | - Charlotte E Buchanan
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, UK
| | - Susan T Francis
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, UK
| | | |
Collapse
|
28
|
Abstract
Background Renal hypoxia, implicated as crucial factor in onset and progression of chronic kidney disease, may be attributed to reduced nitric oxide because nitric oxide dilates vasculature and inhibits mitochondrial oxygen consumption. We hypothesized that chronic nitric oxide synthase inhibition would induce renal hypoxia. Methods and Results Oxygen-sensitive electrodes, attached to telemeters, were implanted in either renal cortex (n=6) or medulla (n=7) in rats. After recovery and stabilization, baseline oxygenation ( pO 2) was recorded for 1 week. To inhibit nitric oxide synthase, N-ω-nitro-l-arginine (L-NNA; 40 mg/kg/day) was administered via drinking water for 2 weeks. A separate group (n=8), instrumented with blood pressure telemeters, followed the same protocol. L-NNA rapidly induced hypertension (165±6 versus 108±3 mm Hg; P<0.001) and proteinuria (79±12 versus 17±2 mg/day; P<0.001). Cortical pO 2, after initially dipping, returned to baseline and then increased. Medullary pO 2 decreased progressively (up to -19±6% versus baseline; P<0.05). After 14 days of L-NNA, amplitude of diurnal medullary pO 2 was decreased (3.7 [2.2-5.3] versus 7.9 [7.5-8.4]; P<0.01), whereas amplitudes of blood pressure and cortical pO 2 were unaltered. Terminal glomerular filtration rate (1374±74 versus 2098±122 μL/min), renal blood flow (5014±336 versus 9966±905 μL/min), and sodium reabsorption efficiency (13.0±0.8 versus 22.8±1.7 μmol/μmol) decreased (all P<0.001). Conclusions For the first time, we show temporal development of renal cortical and medullary oxygenation during chronic nitric oxide synthase inhibition in unrestrained conscious rats. Whereas cortical pO 2 shows transient changes, medullary pO 2 decreased progressively. Chronic L-NNA leads to decreased renal perfusion and sodium reabsorption efficiency, resulting in progressive medullary hypoxia, suggesting that juxtamedullary nephrons are potentially vulnerable to prolonged nitric oxide depletion.
Collapse
Affiliation(s)
- Tonja W. Emans
- Internal Medicine‐NephrologyAmsterdam UMC / Academic Medical Centre at the University of AmsterdamThe Netherlands
- Nephrology and HypertensionUniversity Medical Centre UtrechtThe Netherlands
| | - Ben J. Janssen
- Pharmacology and ToxicologyMaastricht UniversityThe Netherlands
| | - Jaap A. Joles
- Nephrology and HypertensionUniversity Medical Centre UtrechtThe Netherlands
| | - C.T. Paul Krediet
- Internal Medicine‐NephrologyAmsterdam UMC / Academic Medical Centre at the University of AmsterdamThe Netherlands
| |
Collapse
|
29
|
Hosokawa K, Su F, Taccone FS, Post EH, Creteur J, Vincent JL. Effects of acute ethanol intoxication in an ovine peritonitis model. BMC Anesthesiol 2018; 18:70. [PMID: 29921225 PMCID: PMC6009814 DOI: 10.1186/s12871-018-0537-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Accepted: 05/30/2018] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Acute ethanol intoxication has been shown to have contrasting effects on outcomes in sepsis. The aim of this study was to explore the effects of acute ethanol intoxication on hemodynamics, renal function, brain perfusion and lactate/pyruvate in an ovine sepsis model. METHODS Anesthetized, mechanically ventilated female sheep were randomized to an ethanol group (n = 7), which received 1 g/kg ethanol diluted in intravenous (i.v.) saline infusion or a control group (n = 7), which received the same volume of i.v. saline. Both groups received the treatment for a period of 2 h prior to induction of sepsis by intraperitoneal injection of feces. Other treatment included fluid resuscitation but no vasopressors or antibiotics. Global hemodynamics, renal blood flow, brain cortex laser Doppler flowmetry and microdialysis analyses were recorded hourly. RESULTS In the ethanol group, blood ethanol concentrations were 137 ± 29 mg/dL at the time of feces injection and decreased to become undetectable by 12 h. Arterial hypotension occurred earlier in the ethanol than in the control group (8 [7-12] vs. 14 [11-20] hours, p = 0.03). Lactate levels increased to > 2 mmol/L earlier in the ethanol group. Renal dysfunction (9 [6-13] vs. 13 [12-15] hours, p = 0.05) and oliguria (urine output < 0.5 mL/kg/h; 10 [7-12] vs. 13 [12, 13] hours, p = 0.01) developed earlier in the ethanol than in the control group. Brain blood flow and lactate/pyruvate were unaffected. There was no significant difference in survival time. CONCLUSIONS Acute ethanol intoxication in this model of peritonitis resulted in earlier development of shock and renal dysfunction but did not alter brain perfusion and metabolism or short-term survival.
Collapse
Affiliation(s)
- Koji Hosokawa
- Department of Intensive Care, Erasme University Hospital, Université Libre de Bruxelles, Brussels, Belgium
| | - Fuhong Su
- Department of Intensive Care, Erasme University Hospital, Université Libre de Bruxelles, Brussels, Belgium
| | - Fabio Silvio Taccone
- Department of Intensive Care, Erasme University Hospital, Université Libre de Bruxelles, Brussels, Belgium
| | - Emiel Hendrik Post
- Department of Intensive Care, Erasme University Hospital, Université Libre de Bruxelles, Brussels, Belgium
| | - Jacques Creteur
- Department of Intensive Care, Erasme University Hospital, Université Libre de Bruxelles, Brussels, Belgium
| | - Jean-Louis Vincent
- Department of Intensive Care, Erasme University Hospital, Université Libre de Bruxelles, Brussels, Belgium
| |
Collapse
|
30
|
Ali A, Addley S, Ong S. Three-dimensional indices of renal perfusion in normal pregnancy and pre-eclampsia. Ir J Med Sci 2018; 188:173-177. [PMID: 29916133 DOI: 10.1007/s11845-018-1844-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 06/08/2018] [Indexed: 11/26/2022]
Abstract
INTRODUCTION We compared renal perfusion in normal pregnant women and women with pre-eclampsia using three-dimensional (3D) ultrasound. We measured the flow index (FI), vascular index (VI) and vascularisation flow index (VFI) which are believed to reflect vascularity and flow intensity. METHODS Fourteen patients with normal pregnancy and 16 patients with pre-eclampsia were recruited. Imaging was conducted using a Voluson E8 machine and a 6-MHz trans-abdominal probe. The inferior border of the maternal left kidney was scanned. Volumes were acquired using 3D power Doppler angiography (3D-PDA). The FI, VI and VFI were generated using 'histogram' facility. RESULTS Maternal characteristics between normal pregnant women and women with pre-eclampsia were not different in terms of maternal age, gestation or body mass index. Depth of insonnation was not different between groups. The FI, VI and the VFI were not different between groups. The mean (SD) for FI was 27.9 (7.4) vs. 27.1 (6.5) between women with normal pregnancy vs. women with pre-eclampsia. For VI, mean (SD) was 72.3(31.6) vs. 79.4 (28.7) respectively. For VFI, mean (SD) was 20.8 (10.8) vs. 20.8 (8.1) respectively. Using the Mann-Whitney U test, no statistical differences between groups were apparent. There was no correlation between FI measurements and maternal creatinine (Pearson's R square = 0.04; p = 0.45) or with maternal urea levels (Pearson's R square = 0.20; p = 0.10). CONCLUSION Using 3D ultrasound, we failed to demonstrate a difference in maternal renal perfusion in normal pregnancy compared to pre-eclampsia. The lack of observed difference may be a reflection of the high variability in 3D measurements (i.e. poor investigative tool) rather than a true lack of difference in renal perfusion.
Collapse
Affiliation(s)
- Amanda Ali
- Fetal Medicine, Royal Jubilee Maternity Hospital, Grosvenor Road, Belfast, BT12 6BB, UK
| | - Susan Addley
- Fetal Medicine, Royal Jubilee Maternity Hospital, Grosvenor Road, Belfast, BT12 6BB, UK
| | - Stephen Ong
- Fetal Medicine, Royal Jubilee Maternity Hospital, Grosvenor Road, Belfast, BT12 6BB, UK.
| |
Collapse
|
31
|
Rahmania L, Orbegozo D, Su F, Taccone FS, Vincent JL, De Backer D. Administration of Tetrahydrobiopterin (BH4) Protects the Renal Microcirculation From Ischemia and Reperfusion Injury. Anesth Analg 2017; 125:1253-1260. [PMID: 28632534 DOI: 10.1213/ane.0000000000002131] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Abdominal aortic aneurysm surgery with suprarenal cross-clamping is often associated with renal injury. Although the mechanism underlying such injury is unclear, tissue ischemia and reperfusion, which induces endothelial dysfunction and decreases the availability of tetrahydrobiopterin (BH4), may play a role. We evaluated whether BH4 administration prevents renal ischemia/reperfusion injury in an animal model of aortic cross-clamping. METHODS Nineteen anesthetized, mechanically ventilated, and invasively monitored adult sheep were randomized into 3 groups: sham animals (n = 5) that underwent surgical preparation but no aortic clamping; an ischemia/reperfusion group (n = 7), where the aorta was clamped above the renal arteries for 1 hour, and a BH4 group (n = 7), in which animals received 20 mg/kg of BH4 followed by aortic cross-clamp for 1 hour. Animals were followed for a maximum of 6 hours after reperfusion. The renal microcirculation was evaluated at baseline (before clamping), and 1, 4, and 6 hours after reperfusion using side-stream dark field videomicroscopy. The renal lactate-to-pyruvate ratio was evaluated using microdialysis. The primary outcome was the change in proportion of small perfused vessels before and after injury. Secondary outcomes were renal tissue redox state and renal function. RESULTS Ischemia/reperfusion injury was associated with increases in heart rate and mean arterial pressure, which were blunted by BH4 administration. From the first to the sixth hour after reperfusion, the small vessel density (estimated mean difference [EMD], 1.03; 95% confidence interval [CI], 0.41-1.64; P = .003), perfused small vessel density (EMD, 0.84; 95% CI, 0.29-1.39; P = .005), and proportion of perfused small vessels (EMD, 8.60; 95% CI, 0.85-16.30; P = .031) were altered less in the BH4 than in the ischemia/reperfusion group. The renal lactate-to-pyruvate ratios were lower in the cortex in the BH4 than in the ischemia/reperfusion group from the first to the sixth hour after reperfusion (EMD, -19.16; 95% CI, -11.06 to 33.16; P = .002) and in the medulla from the first to the fourth hour (EMD, -26.62; 95% CI, -18.32 to 38.30; P = .020; and EMD, -8.68; 95% CI, -5.96 to 12.65; P = .019). At the sixth hour, serum creatinine was lower in the BH4 than in the ischemia/reperfusion group (EMD, -3.36; 95% CI, -0.29 to 1.39; P = .026). CONCLUSIONS In this sheep model of renal ischemia/reperfusion, BH4 pretreatment reduced renal microvascular injury and improved renal metabolism and function. Further work is needed to clarify the potential role of BH4 in ischemia/reperfusion injury.
Collapse
Affiliation(s)
- Lokmane Rahmania
- From the Department of Intensive Care, Erasme Hospital, Université Libre de Bruxelles, Brussels, Belgium
| | | | | | | | | | | |
Collapse
|
32
|
Affiliation(s)
- Alejandro R Chade
- From the Department of Physiology and Biophysics, Center for Excellence in Cardiovascular-Renal Research, Department of Medicine, and Department of Radiology, University of Mississippi Medical Center, Jackson.
| |
Collapse
|
33
|
Abstract
BACKGROUND Urine production in the kidney is generally thought to be an energy-intensive process requiring large amounts of metabolic activity to power active transport mechanisms. This study uses a thermodynamic analysis to evaluate the minimum work requirements for urine production in the human kidney and provide a new perspective on the energy costs of urine production. In this study, black-box models are used to compare the Gibbs energy inflow and outflow of the overall kidney and physiologically-based subsections in the kidney, to calculate the work of separation for urine production. RESULTS The results describe the work done during urine production broadly and for specific scenarios. Firstly, it shows glomerular filtration in both kidneys requires work to be done at a rate of 5 mW under typical conditions in the kidney. Thereafter, less than 54 mW is sufficient to concentrate the filtrate into urine, even in the extreme cases considered. We have also related separation work in the kidney with the excretion rates of individual substances, including sodium, potassium, urea and water. Lastly, the thermodynamic calculations indicate that plasma dilution significantly reduces the energy cost of separating urine from blood. CONCLUSIONS A comparison of these thermodynamic results with physiological reference points, elucidates how various factors affect the energy cost of the process. Surprisingly little energy is required to produce human urine, seeing that double the amount of work can theoretically be done with all the energy provided through pressure drop of blood flow through the kidneys, while the metabolic energy consumption of the kidneys could possibly drive almost one hundred times more separation work. Nonetheless, the model's outputs, which are summarised graphically, show the separation work's nuances, which can be further analysed in the context of more empirical evidence.
Collapse
Affiliation(s)
- Robert H Louw
- Materials and Process Synthesis (MaPS) Research Unit, University of South Africa, Pioneer Avenue, Roodepoort, 1709, South Africa.
| | - David M Rubin
- Biomedical Engineering Research Group, School of Electrical and Information Engineering, University of the Witwatersrand, 1 Jan Smuts Avenue, Johannesburg, 2000, South Africa
| | - David Glasser
- Materials and Process Synthesis (MaPS) Research Unit, University of South Africa, Pioneer Avenue, Roodepoort, 1709, South Africa
| | - Robyn F R Letts
- Biomedical Engineering Research Group, School of Electrical and Information Engineering, University of the Witwatersrand, 1 Jan Smuts Avenue, Johannesburg, 2000, South Africa
| | - Diane Hildebrandt
- Materials and Process Synthesis (MaPS) Research Unit, University of South Africa, Pioneer Avenue, Roodepoort, 1709, South Africa
| |
Collapse
|
34
|
Wilson TE. Renal sympathetic nerve, blood flow, and epithelial transport responses to thermal stress. Auton Neurosci 2016; 204:25-34. [PMID: 28043810 DOI: 10.1016/j.autneu.2016.12.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2016] [Revised: 11/28/2016] [Accepted: 12/20/2016] [Indexed: 12/12/2022]
Abstract
Thermal stress is a profound sympathetic stress in humans; kidney responses involve altered renal sympathetic nerve activity (RSNA), renal blood flow, and renal epithelial transport. During mild cold stress, RSNA spectral power but not total activity is altered, renal blood flow is maintained or decreased, and epithelial transport is altered consistent with a sympathetic stress coupled with central volume loaded state. Hypothermia decreases RSNA, renal blood flow, and epithelial transport. During mild heat stress, RSNA is increased, renal blood flow is decreased, and epithelial transport is increased consistent with a sympathetic stress coupled with a central volume unloaded state. Hyperthermia extends these directional changes, until heat illness results. Because kidney responses are very difficult to study in humans in vivo, this review describes and qualitatively evaluates an in vivo human skin model of sympathetically regulated epithelial tissue compared to that of the nephron. This model utilizes skin responses to thermal stress, involving 1) increased skin sympathetic nerve activity (SSNA), decreased skin blood flow, and suppressed eccrine epithelial transport during cold stress; and 2) increased SSNA, skin blood flow, and eccrine epithelial transport during heat stress. This model appears to mimic aspects of the renal responses. Investigations of skin responses, which parallel certain renal responses, may aid understanding of epithelial-sympathetic nervous system interactions during cold and heat stress.
Collapse
Affiliation(s)
- Thad E Wilson
- Division of Biomedical Sciences, Marian University College of Osteopathic Medicine, Indianapolis, IN, USA.
| |
Collapse
|
35
|
Huang H, Chang HH, Xu Y, Reddy DS, Du J, Zhou Y, Dong Z, Falck JR, Wang MH. Epoxyeicosatrienoic Acid Inhibition Alters Renal Hemodynamics During Pregnancy. Exp Biol Med (Maywood) 2016; 231:1744-52. [PMID: 17138762 DOI: 10.1177/153537020623101112] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
In this study we examined the expression of cytochrome P450 (CYP) 2C and CYP2J Isoforms in renal proximal tubules and microvessels isolated from rats at different stages of pregnancy. We also selectively inhibited epoxyeicosatrienoic acid (EET) production by the administration of N-methanesulfonyl-6-(2-proparyloxyphenyl)hexanamide (MSPPOH 20 mg/kg/day iv) to rats during Days 14–17 of gestation and to age-matched virgin rats and determined the consequent effects on renal function. Western blot analysis showed that CYP2C11, CYP2C23, and CYP2J2 expression was significantly increased in the renal microvessels of pregnant rats on Day 12 of gestation. In the proximal tubules, CYP2C23 expression was significantly increased throughout pregnancy, while the expression of CYP2C11 was increased in early and late pregnancy and the expression of CYP2J2 was increased in middle and late pregnancy. MSPPOH treatment significantly Increased pregnant rats’ mean arterial pressure, renal vascular resistance, and sodium balance but significantly decreased renal blood flow, glomerular filtration rate, and urinary sodium excretion, as well as fetal pups’ body weight and length. In contrast, MSPPOH treatment had no effect on renal hemodynamics or urinary sodium excretion in age-matched virgin rats. In pregnant rats, MSPPOH treatment also caused selective inhibition of renal cortical EET production and significantly decreased the expression of CYP2C11, CYP2C23, and CYP2J2 in the renal cortex, renal microvessels, and proximal tubules. These results suggest that upregulation of renal vascular and tubular EETs contributes to the control of blood pressure and renal function during pregnancy.
Collapse
Affiliation(s)
- Hui Huang
- Department of Physiology, Medical College of Georgia, Augusta, GA 30912, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
36
|
Alnaeb ME, Youssef F, Mikhailidis DP, Hamilton G. Short-term Lipid-Lowering Treatment with Atorvastatin Improves Renal Function But Not Renal Blood Flow Indices in Patients with Peripheral Arterial Disease. Angiology 2016; 57:65-71. [PMID: 16444458 DOI: 10.1177/000331970605700109] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Some studies have suggested that lipid lowering with statins exerts favorable effects on the progression of chronic kidney disease. Therefore, the authors assessed the effects of short-term atorvastatin treatment on biochemical markers of renal function and evaluated duplex indices of renal blood flow (RBF) in patients with peripheral arterial disease. Hyperlipidemic claudicants (n=18), aged 44-85 years, were treated for 8 weeks with 20 mg/day atorvastatin. Blood tests at baseline and after 8 weeks included serum fasting lipids, creatinine, urate, and cystatin C (a sensitive indicator of renal function) levels. RBF was also assessed (n=9) by measuring pulsatile and resistance duplex indices. As expected, there was a significant improvement in total cholesterol, low-density lipoprotein cholesterol, and triglycerides. There was also a significant (p<0.0001) fall in serum creatinine from 89 (58-125) to 79 µmol/L (54-119) and an increase in calculated creatinine clearance (CrCl) from 72 (40-129) to 80 mL/minute (47-138; p<0.0001). Serum cystatin C values decreased significantly (p=0.0002) from 1.04 (0.57-1.56) to 0.90 mg/L (0.47-1.47). There were no detectable changes in the RBF duplex indices. Treatment of stable claudicants with atorvastatin for 8 weeks was associated with improved renal function (as assessed by serum creatinine, cystatin C, and calculated CrCl) without changes in RBF. Further studies are required to identify the mechanisms involved in this phenomenon.
Collapse
Affiliation(s)
- M E Alnaeb
- University Department of Surgery, Royal Free Hospital NHS Trust and Royal Free and University College Medical School, University College London, London, UK
| | | | | | | |
Collapse
|
37
|
Abstract
The new millennium ushered in a number of changes in cardiac surgery. Off-pump coronary artery bypass surgery became technically easier so that multivessel surgery became less of a challenge and cardiologists were supplied with new catheters that accessed lesions that were previously thought of as being unapproachable. New drugs were introduced that made the management of heart failure patients feasible on an outpatient basis, and new devices extend the bridging period to transplantation. However, these advances have not necessarily been attended by significant improvements in outcome, possibly because the less challengng a procedure becomes, the sicker the patients that can be managed. This observation is particularly true with the incidence and outcome of renal failure after cardiac surgery. Bypass factors have been manipulated without much effect, and the traditional drugs that were found to increase renal blood flow in animal experiments did not translate into clinical improvement in renal outcome. Recent research has given us insight into the pathophysiology of ischemic acute renal failure, and it has been found that the paradigm was not as simple as previously thought, possibly accounting for the failure of the more traditional renal drugs (dopamine, mannitol and diuretics). However, these new insights open up the possibility of novel targets for renal protection and repair.
Collapse
Affiliation(s)
- Susan Garwood
- Department of Anesthesiology, Yale University School of Medicine, New Haven, CT 06510, USA.
| |
Collapse
|
38
|
Skov K, Madsen JK, Hansen HE, Zagato L, Frandsen E, Bianchi G, Mulvany MJ. Renal Haemodynamics are not Related to Genotypes in Offspring of Parents with Essential Hypertension. J Renin Angiotensin Aldosterone Syst 2016; 7:47-55. [PMID: 17083073 DOI: 10.3317/jraas.2006.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Introduction. The pathogenesis of essential hypertension (EH) has a major genetic component and is associated with renal abnormalities. Normotensive offspring of hypertensive parents are likely to develop EH and are a suitable population for identifying possible relations between genetic and renal abnormalities.Methods. We investigated if renin-angiotensin-aldosterone system associated genotypes (angiotensinogen [M235T] and ACE [I/D]) are related to blood pressure (BP), renal haemodynamics and sodium excretion in sex and age-matched (18—35 years) healthy Caucasian offspring of either two parents with EH (n=101, EH-offspring) or two normotensive parents (n=50, controls). The alpha-adducin polymorphism (G460W) was also investigated.Results. Compared to controls, BP, heart rate, renal vascular resistance (RVR) and urinary sodium excretion were, respectively, 5%, 7%, 15% and 20% higher in EH-offspring. In controls, the TT-genotype of the M235T angiotensinogen polymorphism was associated with higher BP and higher plasma angiotensinogen. By contrast, in EHoffspring the TT-genotype was associated with lower BP and unchanged plasma angiotensinogen. Plasma angiotensinogen correlated positively with BP in EH-offspring, with a similar tendency (p=0.08) in controls. The distributions of the three candidate polymorphisms were similar in EH-offspring and controls. There were no associations between any of the polymorphisms and any of the renal parameters measured.Conclusion. The markedly greater RVR, proportionally larger than the greater BP, supports a role for RVR in the pathogenesis of EH. The lack of association between the candidate polymorphisms and the investigated parameters, even in this homogenous and for hypertension strongly predisposed group, suggests that the polymorphisms investigated do not play important roles in the pathogenesis of hypertension.
Collapse
Affiliation(s)
- Karin Skov
- Department of Nephrology, Aarhus University Hospital, Aarhus, Denmark
| | | | | | | | | | | | | |
Collapse
|
39
|
Abstract
Acute renal failure (ARF) is common in the critically ill and is associated with a high mortality rate. Its pathogenesis is not understood. Because animal models use ischemia to induce experimental ARF, there is the widespread belief that lack of blood flow is responsible for ARF. Low-dose dopamine (LDD) has been shown to increase renal blood flow in animal and in human volunteers. Thus, it has been administered to humans for almost 3 decades in the belief that it would lead to renal arterial vasodilation and increase renal blood flow (RBF). However, the etiology of ARF in critical illness is likely multifactorial, and the contribution of hypovolemia and reduced renal perfusion is unknown. Furthermore, interindividual variation in the pharmacokinetics of dopamine typically results in poor correlation between blood levels and administered dose, making accurate and reliable delivery of LDD difficult. Finally, dopamine is a proximal tubular diuretic that increases Na+ delivery to tubular cells, thus increasing their oxygen demands. Accordingly, even if LDD were able to preferentially increase RBF, there is no guarantee that it would restore renal parenchymal oxygen homeostasis. More important, 2 meta-analyses and a large double-blind, prospective, multiple-center, randomized controlled trial have failed to demonstrate that dopamine protects the kidney in critically ill patients with ARF. Currently, there is insufficient evidence to support the use of renal-dose dopamine in the intensive care unit.
Collapse
Affiliation(s)
- Daryl Jones
- Department of Intensive Care, Melbourne University, Austin Hospital, Melbourne, Australia
| | | |
Collapse
|
40
|
Bakoyiannis CN, Cagiannos C, Wasilljew S, Pinter L, Kolvenbach R. Laparoscopy-Assisted Hybrid Technique for Renal Revascularization Using an Endovascular Graft: Report of Three Cases. Vascular 2016; 15:154-7. [PMID: 17573021 DOI: 10.2310/6670.2007.00036] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Atherosclerotic renal artery stenosis (RAS) is relatively common and often associated with hypertension and progressive renal insufficiency. Technical improvements of interventional endovascular tools have led to a more widespread use of endoluminal renal artery revascularization. Sometimes an endovascular procedure for (RAS) may fail. We report 3 cases successfully treated with laparoscopic assisted aortorenal bypass using an endovascular graft.
Collapse
|
41
|
De Lutiis MA, Felaco M, Gizzi F, Patruno A, Speranza L, Di Giulio C, Conti P, Castellani ML, Petrarca C, Grilli A. A Scavenger Role for Nitric Oxide in the Aged Rat Kidney. Int J Immunopathol Pharmacol 2016; 17:265-71. [PMID: 15461860 DOI: 10.1177/039463200401700306] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Progressive ageing is associated with an increment of biomolecules modified through oxidation as a result of the action of free radicals deriving from reactive oxygen species that attack biomolecules. During ageing many alterations of renal functions have been reported. Renal ageing is associated with a progressive decline of glomerular filtration, renal blood flow and augmented vascular resistance. The kidney is a very important source of inducible nitric oxide synthase (iNOS) in both epithelial and vascular structures. In this study we have investigated mRNA and protein iNOS expression and localization and nitric oxide (NO) production in young and aged rats. An increased expression of iNOS occurs in rat kidney during ageing. In the aged rat, an increase in the values of both iNOS-RNA and iNOS protein was observed through rtPCR and Western blot analysis. The activities of three isoforms of NOS were also seen. In the aged rat kidney the production of NO decreased, due to the reduction of the activities of the three NOS. This suggests that in the aged rat a progressive increase of superoxide anion does not imply an increase in the production of NO which functions as a scavenger molecule, causing oxidative stress with accumulation of reactive oxygen species (ROS).
Collapse
Affiliation(s)
- M A De Lutiis
- Department of Biomorphology, University "G. D'Annunzio" of Chieti, Chieti Scalo, Italy
| | | | | | | | | | | | | | | | | | | |
Collapse
|
42
|
Scully CG, Mitrou N, Braam B, Cupples WA, Chon KH. Detecting Interactions between the Renal Autoregulation Mechanisms in Time and Space. IEEE Trans Biomed Eng 2016; 64:690-698. [PMID: 27244712 DOI: 10.1109/tbme.2016.2569453] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Our objective is to identify localized interactions between the renal autoregulation mechanisms over time. METHODS A time-varying phase-randomized wavelet bicoherence detector for quadratic phase coupling between tubuloglomerular feedback and the myogenic response is presented. Through simulations we show its ability to interrogate quadratic phase coupling. The method is applied to kidney blood flow and laser speckle imaging sequences of cortical perfusion from anesthetized rats before and after nonselective inhibition of nitric-oxide synthase. RESULTS Quadratic phase coupling in kidney blood flow data was present in four out of nine animals during the control period for 13.0 ± 5.6% (mean ± SD) of time and in five out of nine animals during inhibition of nitric-oxide synthase for 15.8 ± 8.2% of time. Approximately 60% of time-series extracted from laser speckle imaging pixels of the renal cortex showed significant quadratic phase coupling. Pixels with significant coupling had a median coupling length of 10.8 ± 2.2% and 12.1 ± 3.1% of time with the 95th percentile of pixels being coupled for 25.5 ± 4.4% and 30.9 ± 6.4% of time during control and inhibition of nitric-oxide synthase, respectively. CONCLUSION These results indicate quadratic phase coupling exists in short time intervals between tubuloglomerular feedback and the myogenic response and is detected more often in local renal perfusion signals than whole kidney blood flow in anesthetized rats. SIGNIFICANCE Combining the detector and laser speckle imaging provides identification of coordination between renal autoregulation mechanisms that is localized in time and space.
Collapse
|
43
|
Sui F, Zheng Y, Li WX, Zhou JL. Renal circulation and microcirculation during intra-abdominal hypertension in a porcine model. Eur Rev Med Pharmacol Sci 2016; 20:452-461. [PMID: 26914119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
OBJECTIVE The purpose of the study is to further investigate the effects of increased intra-abdominal pressure (IAP) on renal hemodynamics and renal perfusion, and to evaluate the renal cortical and sublingual microcirculation by sidestream dark field (SDF) imaging, both with a porcine model. MATERIALS AND METHODS IAP was increased stepwise to 10, 15, 20, 25 mmHg, during which hemodynamic parameters, urinary output, renal contrast-enhanced ultrasound (CEUS), sublingual and renal SDF videos were all recorded from 12 pigs. RESULTS Wash in time (WT) and time to peak (TTP) prolonged significantly (p<0.05), while peak intensity (PI) wash in slope (WS) and AUC (area under curve) in CEUS declined significantly (p<0.05) compared with baseline when IAP elevated to 25 mm Hg. With an increase of abdominal pressure, sublingual microvascular flow index (MFI) drop significantly, especially upon IAP was over 20 mmHg. But other parameters such as the total vascular density (TVD), De Backer Score, proportion of perfused vessels (PPV), perfused vessel density (PVD), and heterogeneity index (HI) of tongue were not significantly changed. With increasing IAP, renal vascular resistance increased and MFI decreased about 30%. RFG, instead of RFG showed a moderate correlation with AUC (R=0.47, p<0.05) and MFI (R=0.49, p<0.05). CONCLUSIONS CEUS is a safe, real-time dynamic, noninvasive and simple technique to evaluate renal microvascular perfusion in intra-abdominal hypertension. Descending slope, PI and AUC can be used for the diagnosis of the renal microvascular damage in a porcine model of IAP-induced renal impairment. Also, SDF on the surface of the kidney is a useful tool to evaluate the microcirculation of kidney but sublingual SDF imaging was barely useful.
Collapse
Affiliation(s)
- F Sui
- Department of Surgical Intensive Care Unit, Department of Orthopedic Surgery; Beijing Chao-yang Hospital Affiliated to Capital Medical University, Beijing, China.
| | | | | | | |
Collapse
|
44
|
Abstract
AIMS The aim of this study was to calculate the normal values of renal functional reserve in healthy individuals measuring the resistive index and pulsatility index using Doppler ultrasonography. MATERIAL AND METHODS Forty healthy volunteer adults were included in the study. Their basal resistive index and pulsatility index values were measured and after oral protein load at 30th, 75th and 120th minutes, resistive index and pulsatility index measurements were repeated. The maximum changes in resistive index and pulsatility index from baseline were calculated in each subject which represented the renal functional reserve. RESULTS The mean values of resistive index and pulsatility index decreased significantly starting with 30 minutes and consecutively at 75 and 120 minutes (for all p<0.05). The highest decrease compared to baseline values was recorded at 75 minutes and renal functional reserve values were calculated as 22.2% for resistive index and 25.4% for pulsatility index. CONCLUSIONS Renal functional reserve can be calculated through Doppler resistive index and pulsatility index measures. We consider that it may be helpful to know normal values of renal functional reserve in healthy subjects.
Collapse
Affiliation(s)
- Mehmet Zekai Pekkafalı
- Gulhane Military Medicine Academy, Haydarpasha Training Hospital, Department of Radiology, Istanbul, Turkey.
| | - Kemal Kara
- Gulhane Military Medicine Academy, Haydarpasha Training Hospital, Department of Radiology, Istanbul, Turkey
| |
Collapse
|
45
|
Verloop WL, Hubens LEG, Spiering W, Doevendans PA, Goldschmeding R, Bleys RLAW, Voskuil M. The Effects of Renal Denervation on Renal Hemodynamics and Renal Vasculature in a Porcine Model. PLoS One 2015; 10:e0141609. [PMID: 26587981 PMCID: PMC4654519 DOI: 10.1371/journal.pone.0141609] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 10/09/2015] [Indexed: 12/20/2022] Open
Abstract
Rationale Recently, the efficacy of renal denervation (RDN) has been debated. It is discussed whether RDN is able to adequately target the renal nerves. Objective We aimed to investigate how effective RDN was by means of functional hemodynamic measurements and nerve damage on histology. Methods and Results We performed hemodynamic measurements in both renal arteries of healthy pigs using a Doppler flow and pressure wire. Subsequently unilateral denervation was performed, followed by repeated bilateral hemodynamic measurements. Pigs were terminated directly after RDN or were followed for 3 weeks or 3 months after the procedure. After termination, both treated and control arteries were prepared for histology to evaluate vascular damage and nerve damage. Directly after RDN, resting renal blood flow tended to increase by 29±67% (P = 0.01). In contrast, renal resistance reserve increased from 1.74 (1.28) to 1.88 (1.17) (P = 0.02) during follow-up. Vascular histopathology showed that most nerves around the treated arteries were located outside the lesion areas (8±7 out of 55±25 (14%) nerves per pig were observed within a lesion area). Subsequently, a correlation was noted between a more impaired adventitia and a reduction in renal resistance reserve (β: -0.33; P = 0.05) at three weeks of follow-up. Conclusion Only a small minority of renal nerves was targeted after RDN. Furthermore, more severe adventitial damage was related to a reduction in renal resistance in the treated arteries at follow-up. These hemodynamic and histological observations may indicate that RDN did not sufficiently target the renal nerves. Potentially, this may explain the significant spread in the response after RDN.
Collapse
Affiliation(s)
- Willemien L. Verloop
- Department of Cardiology, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Lisette E. G. Hubens
- Department of Cardiology, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Wilko Spiering
- Department of Vascular Medicine, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Pieter A. Doevendans
- Department of Cardiology, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Roel Goldschmeding
- Department of Pathology, University Medical Center Utrecht, Utrecht, the Netherlands
| | | | - Michiel Voskuil
- Department of Cardiology, University Medical Center Utrecht, Utrecht, the Netherlands
- * E-mail:
| |
Collapse
|
46
|
Mezentseva LV, Pertsov SS, Hugaeva VK. [Studying the Persistence of Blood Flow Oscillations in Rat Kidneys]. Biofizika 2015; 60:1186-1190. [PMID: 26841515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
This work was designed to study the nonlinear dynamics of fluctuations in renal blood flow of rats under basal conditions and in the perturbed state. An intramuscular injection of aspirin in 0.9% physiological saline (0.5 mg per 100 g body weight) served as a perturbation factor. Capillary blood flow in the right kidney of a rat was measured by the method of laser Doppler flowmetry. The persistence of these time series was estimated by the Hurst method. Our study revealed the persistence of time series under basal conditions (Hurst index H = 0.817 ± 0.041). Statistical parameters of the perturbed series were shown to differ significantly from those observed in the initial state. However, the perturbed series remained persistent. The Hurst index for these series was H = 0.677 ± 0.057. A decrease in this index was insignificant (as compared to that for the baseline index).
Collapse
|
47
|
Georgianos PI, Sarafidis PA, Liakopoulos V. Arterial Stiffness: A Novel Risk Factor for Kidney Injury Progression? Am J Hypertens 2015; 28:958-65. [PMID: 25687879 DOI: 10.1093/ajh/hpv004] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Accepted: 01/05/2015] [Indexed: 02/06/2023] Open
Abstract
Arterial stiffness is typical feature of vascular remodeling in chronic kidney disease (CKD). Increased arterial stiffness raises flow and pressure pulsatility and is considered the principle pathogenic mechanism of isolated systolic hypertension, left ventricular hypertrophy, and congestive heart failure. Apart from the impact of arterial stiffness on left ventricular afterload, downstream transmission of pressure pulsatility to the level of microcirculation is suggested to promote injury of other susceptible organs. This may be of particular importance for kidney injury progression, since passive renal perfusion along with low resistance and input impedance in renal microvessels make kidneys particularly vulnerable to the damaging effect of systemic pulsatile pressure. Recent studies have provided evidence that arterial stiffness culminates in elevated pulsatility and resistance in renal microvasculature, promoting structural damage of small intra-renal arterioles. Further, prospective observational studies have shown that reduced aortic compliance is closely associated with the annual rate of renal function decline and represents independent predictor of kidney injury progression to end-stage renal disease among patients with CKD. This article provides insights into the cross-talk between macrocirculation and renal microcirculation and summarizes the currently available clinical evidence linking increased arterial stiffness with kidney disease progression.
Collapse
Affiliation(s)
- Panagiotis I Georgianos
- Section of Nephrology and Hypertension, 1st Department of Medicine, AHEPA Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece;
| | - Pantelis A Sarafidis
- Department of Nephrology, Hippokration Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Vassilios Liakopoulos
- Section of Nephrology and Hypertension, 1st Department of Medicine, AHEPA Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece
| |
Collapse
|
48
|
Osei-Owusu P, Owens EA, Jie L, Reis JS, Forrester SJ, Kawai T, Eguchi S, Singh H, Blumer KJ. Regulation of Renal Hemodynamics and Function by RGS2. PLoS One 2015; 10:e0132594. [PMID: 26193676 PMCID: PMC4508038 DOI: 10.1371/journal.pone.0132594] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2014] [Accepted: 06/16/2015] [Indexed: 12/16/2022] Open
Abstract
Regulator of G protein signaling 2 (RGS2) controls G protein coupled receptor (GPCR) signaling by acting as a GTPase-activating protein for heterotrimeric G proteins. Certain Rgs2 gene mutations have been linked to human hypertension. Renal RGS2 deficiency is sufficient to cause hypertension in mice; however, the pathological mechanisms are unknown. Here we determined how the loss of RGS2 affects renal function. We examined renal hemodynamics and tubular function by monitoring renal blood flow (RBF), glomerular filtration rate (GFR), epithelial sodium channel (ENaC) expression and localization, and pressure natriuresis in wild type (WT) and RGS2 null (RGS2-/-) mice. Pressure natriuresis was determined by stepwise increases in renal perfusion pressure (RPP) and blood flow, or by systemic blockade of nitric oxide synthase with L-NG-Nitroarginine methyl ester (L-NAME). Baseline GFR was markedly decreased in RGS2-/- mice compared to WT controls (5.0 ± 0.8 vs. 2.5 ± 0.1 μl/min/g body weight, p<0.01). RBF was reduced (35.4 ± 3.6 vs. 29.1 ± 2.1 μl/min/g body weight, p=0.08) while renal vascular resistance (RVR; 2.1 ± 0.2 vs. 3.0 ± 0.2 mmHg/μl/min/g body weight, p<0.01) was elevated in RGS2-/- compared to WT mice. RGS2 deficiency caused decreased sensitivity and magnitude of changes in RVR and RBF after a step increase in RPP. The acute pressure–natriuresis curve was shifted rightward in RGS2-/- relative to WT mice. Sodium excretion rate following increased RPP by L-NAME was markedly decreased in RGS2-/- mice and accompanied by increased translocation of ENaC to the luminal wall. We conclude that RGS2 deficiency impairs renal function and autoregulation by increasing renal vascular resistance and reducing renal blood flow. These changes impair renal sodium handling by favoring sodium retention. The findings provide a new line of evidence for renal dysfunction as a primary cause of hypertension.
Collapse
Affiliation(s)
- Patrick Osei-Owusu
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania, 19102, United States of America
- * E-mail:
| | - Elizabeth A. Owens
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania, 19102, United States of America
| | - Li Jie
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania, 19102, United States of America
| | - Janaina S. Reis
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania, 19102, United States of America
| | - Steven J. Forrester
- Cardiovascular Research Center and Department of Physiology, Temple University, Philadelphia, Pennsylvania, 19140, United States of America
| | - Tatsuo Kawai
- Cardiovascular Research Center and Department of Physiology, Temple University, Philadelphia, Pennsylvania, 19140, United States of America
| | - Satoru Eguchi
- Cardiovascular Research Center and Department of Physiology, Temple University, Philadelphia, Pennsylvania, 19140, United States of America
| | - Harpreet Singh
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania, 19102, United States of America
| | - Kendall J. Blumer
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri, 63110, United States of America
| |
Collapse
|
49
|
Dillon C, Roemer R, Payne A. Magnetic resonance temperature imaging-based quantification of blood flow-related energy losses. NMR Biomed 2015; 28:840-851. [PMID: 25973583 PMCID: PMC4510856 DOI: 10.1002/nbm.3318] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 04/03/2015] [Accepted: 04/07/2015] [Indexed: 06/04/2023]
Abstract
This study presents a new approach for evaluating bioheat transfer equation (BHTE) models used in treatment planning, control and evaluation of all thermal therapies. First, 3D magnetic resonance temperature imaging (MRTI) data are used to quantify blood flow-related energy losses, including the effects of perfusion and convection. Second, this information is used to calculate parameters of a BHTE model: in this paper the widely used Pennes BHTE. As a self-consistency check, the BHTE parameters are utilized to predict the temperatures from which they were initially derived. The approach is evaluated with finite-difference simulations and implemented experimentally with focused ultrasound heating of an ex vivo porcine kidney perfused at 0, 20 and 40 ml/min (n = 4 each). The simulation results demonstrate accurate quantification of blood flow-related energy losses, except in regions of sharp blood flow discontinuities, where the transitions are spatially smoothed. The smoothed transitions propagate into estimates of the Pennes perfusion parameter but have limited effect on the accuracy of temperature predictions using these estimates. Longer acquisition time periods mitigate the effects of MRTI noise, but worsen the effect of flow discontinuities. For the no-flow kidney experiments the estimates of a uniform, constant Pennes perfusion parameter are approximately zero, and at 20 and 40 ml/min the average estimates increase with flow rate to 3.0 and 4.2 kg/m(3) /s, respectively. When Pennes perfusion parameter values are allowed to vary spatially, but remain temporally constant, BHTE temperature predictions are more accurate than when using spatially uniform, constant Pennes perfusion values, with reductions in RMSE values of up to 79%. Locations with large estimated perfusion values correspond to high flow regions of the kidney observed in T1 -weighted MR images. This novel, MRTI-based technique holds promise for improving understanding of thermal therapy biophysics and for evaluating biothermal models.
Collapse
Affiliation(s)
| | - Robert Roemer
- University of Utah, Mechanical Engineering, Salt Lake City, UT, USA
| | - Allison Payne
- University of Utah, Radiology, Salt Lake City, UT, USA
| |
Collapse
|
50
|
Sun A, Tian X, Zhang N, Xu Z, Deng X, Liu M, Liu X. Does lower limb exercise worsen renal artery hemodynamics in patients with abdominal aortic aneurysm? PLoS One 2015; 10:e0125121. [PMID: 25946196 PMCID: PMC4422666 DOI: 10.1371/journal.pone.0125121] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 03/20/2015] [Indexed: 11/19/2022] Open
Abstract
Renal artery stenosis (RAS) and renal complications emerge in some patients after endovascular aneurysm repair (EVAR) to treat abdominal aorta aneurysm (AAA). The mechanisms for the causes of these problems are not clear. We hypothesized that for EVAR patients, lower limb exercise could negatively influence the physiology of the renal artery and the renal function, by decreasing the blood flow velocity and changing the hemodynamics in the renal arteries. To evaluate this hypothesis, pre- and post-operative models of the abdominal aorta were reconstructed based on CT images. The hemodynamic environment was numerically simulated under rest and lower limb exercise conditions. The results revealed that in the renal arteries, lower limb exercise decreased the wall shear stress (WSS), increased the oscillatory shear index (OSI) and increased the relative residence time (RRT). EVAR further enhanced these effects. Because these parameters are related to artery stenosis and atherosclerosis, this preliminary study concluded that lower limb exercise may increase the potential risk of inducing renal artery stenosis and renal complications for AAA patients. This finding could help elucidate the mechanism of renal artery stenosis and renal complications after EVAR and warn us to reconsider the management and nursing care of AAA patients.
Collapse
Affiliation(s)
- Anqiang Sun
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Xiaopeng Tian
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Nan Zhang
- Radiologic Department, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Zaipin Xu
- College of Animal Science, Guizhou University, Guiyang, China
| | - Xiaoyan Deng
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Ming Liu
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Xiao Liu
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
- * E-mail:
| |
Collapse
|