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Abstract
Intrarenal autoregulatory mechanisms maintain renal blood flow (RBF) and glomerular filtration rate (GFR) independent of renal perfusion pressure (RPP) over a defined range (80-180 mmHg). Such autoregulation is mediated largely by the myogenic and the macula densa-tubuloglomerular feedback (MD-TGF) responses that regulate preglomerular vasomotor tone primarily of the afferent arteriole. Differences in response times allow separation of these mechanisms in the time and frequency domains. Mechanotransduction initiating the myogenic response requires a sensing mechanism activated by stretch of vascular smooth muscle cells (VSMCs) and coupled to intracellular signaling pathways eliciting plasma membrane depolarization and a rise in cytosolic free calcium concentration ([Ca(2+)]i). Proposed mechanosensors include epithelial sodium channels (ENaC), integrins, and/or transient receptor potential (TRP) channels. Increased [Ca(2+)]i occurs predominantly by Ca(2+) influx through L-type voltage-operated Ca(2+) channels (VOCC). Increased [Ca(2+)]i activates inositol trisphosphate receptors (IP3R) and ryanodine receptors (RyR) to mobilize Ca(2+) from sarcoplasmic reticular stores. Myogenic vasoconstriction is sustained by increased Ca(2+) sensitivity, mediated by protein kinase C and Rho/Rho-kinase that favors a positive balance between myosin light-chain kinase and phosphatase. Increased RPP activates MD-TGF by transducing a signal of epithelial MD salt reabsorption to adjust afferent arteriolar vasoconstriction. A combination of vascular and tubular mechanisms, novel to the kidney, provides for high autoregulatory efficiency that maintains RBF and GFR, stabilizes sodium excretion, and buffers transmission of RPP to sensitive glomerular capillaries, thereby protecting against hypertensive barotrauma. A unique aspect of the myogenic response in the renal vasculature is modulation of its strength and speed by the MD-TGF and by a connecting tubule glomerular feedback (CT-GF) mechanism. Reactive oxygen species and nitric oxide are modulators of myogenic and MD-TGF mechanisms. Attenuated renal autoregulation contributes to renal damage in many, but not all, models of renal, diabetic, and hypertensive diseases. This review provides a summary of our current knowledge regarding underlying mechanisms enabling renal autoregulation in health and disease and methods used for its study.
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Affiliation(s)
- Mattias Carlström
- Department of Medicine, Division of Nephrology and Hypertension and Hypertension, Kidney and Vascular Research Center, Georgetown University, Washington, District of Columbia; Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden; and Department of Cell Biology and Physiology, UNC Kidney Center, and McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Christopher S Wilcox
- Department of Medicine, Division of Nephrology and Hypertension and Hypertension, Kidney and Vascular Research Center, Georgetown University, Washington, District of Columbia; Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden; and Department of Cell Biology and Physiology, UNC Kidney Center, and McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - William J Arendshorst
- Department of Medicine, Division of Nephrology and Hypertension and Hypertension, Kidney and Vascular Research Center, Georgetown University, Washington, District of Columbia; Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden; and Department of Cell Biology and Physiology, UNC Kidney Center, and McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
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Braun MC, Herring SM, Gokul N, Monita M, Bell R, Zhu Y, Gonzalez-Garay ML, Wenderfer SE, Doris PA. Hypertensive renal injury is associated with gene variation affecting immune signaling. ACTA ACUST UNITED AC 2014; 7:903-10. [PMID: 25366137 DOI: 10.1161/circgenetics.114.000533] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
BACKGROUND The spontaneously hypertensive rat (SHR) strain exists in lines that contrast strongly in susceptibility to renal injury in hypertension. These inbred lines share common ancestry, and only 13% of their genomes arise from different ancestors. METHODS AND RESULTS We used next gen sequencing to detect natural allelic variation in 5 genes of the immunoreceptor signaling pathway (IgH, Dok3, Src, Syk, and JunD) that arise from different ancestors in the injury-prone SHR-A3 and the resistant SHR-B2 lines. We created an intercross between these lines, and in the F2 progeny, we observed that the inheritance of haplotype blocks containing the SHR-A3 alleles of these 5 genes correlated with increased albuminuria and histological measures of renal injury. To test whether accumulated genetic variation in this pathway may create a therapeutic target in hypertensive renal injury, rats of both lines were treated with the immunosuppressant mycophenolate mofetil (MMF). MMF reduced proteinuria (albumin to creatinine ratio) from 6.6 to 1.2 mg/mg (P<0.001) in SHR-A3. Glomerular injury scores were reduced in MMF-treated SHR-A3 from 1.6 to 1.4 (P<0.002). Tubulo-interstitial injury was reduced in MMF-treated SHR-A3 from 2.62 to 2.0 (P=0.001). MMF treatment also reduced renal fibrosis in SHR-A3 (3.9 versus 2.0; P<0.001). CONCLUSIONS Polygenic susceptibility to renal injury in hypertension arises in association with genetic variation in genes that participate in immune responses and is dramatically improved by reduction of immune system activity.
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Affiliation(s)
- Michael C Braun
- From the Department of Pediatrics, Baylor College of Medicine (M.C.B., S.E.W.), and Institute of Molecular Medicine (S.M.H., N.G., M.M., R.B., Y.Z., M.L.G.-G., P.A.D.), University of Texas Health Science Center at Houston
| | - Stacy M Herring
- From the Department of Pediatrics, Baylor College of Medicine (M.C.B., S.E.W.), and Institute of Molecular Medicine (S.M.H., N.G., M.M., R.B., Y.Z., M.L.G.-G., P.A.D.), University of Texas Health Science Center at Houston
| | - Nisha Gokul
- From the Department of Pediatrics, Baylor College of Medicine (M.C.B., S.E.W.), and Institute of Molecular Medicine (S.M.H., N.G., M.M., R.B., Y.Z., M.L.G.-G., P.A.D.), University of Texas Health Science Center at Houston
| | - Monique Monita
- From the Department of Pediatrics, Baylor College of Medicine (M.C.B., S.E.W.), and Institute of Molecular Medicine (S.M.H., N.G., M.M., R.B., Y.Z., M.L.G.-G., P.A.D.), University of Texas Health Science Center at Houston
| | - Rebecca Bell
- From the Department of Pediatrics, Baylor College of Medicine (M.C.B., S.E.W.), and Institute of Molecular Medicine (S.M.H., N.G., M.M., R.B., Y.Z., M.L.G.-G., P.A.D.), University of Texas Health Science Center at Houston
| | - Yaming Zhu
- From the Department of Pediatrics, Baylor College of Medicine (M.C.B., S.E.W.), and Institute of Molecular Medicine (S.M.H., N.G., M.M., R.B., Y.Z., M.L.G.-G., P.A.D.), University of Texas Health Science Center at Houston
| | - Manuel L Gonzalez-Garay
- From the Department of Pediatrics, Baylor College of Medicine (M.C.B., S.E.W.), and Institute of Molecular Medicine (S.M.H., N.G., M.M., R.B., Y.Z., M.L.G.-G., P.A.D.), University of Texas Health Science Center at Houston
| | - Scott E Wenderfer
- From the Department of Pediatrics, Baylor College of Medicine (M.C.B., S.E.W.), and Institute of Molecular Medicine (S.M.H., N.G., M.M., R.B., Y.Z., M.L.G.-G., P.A.D.), University of Texas Health Science Center at Houston
| | - Peter A Doris
- From the Department of Pediatrics, Baylor College of Medicine (M.C.B., S.E.W.), and Institute of Molecular Medicine (S.M.H., N.G., M.M., R.B., Y.Z., M.L.G.-G., P.A.D.), University of Texas Health Science Center at Houston.
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Lazar J, O'Meara CC, Sarkis AB, Prisco SZ, Xu H, Fox CS, Chen MH, Broeckel U, Arnett DK, Moreno C, Provoost AP, Jacob HJ. SORCS1 contributes to the development of renal disease in rats and humans. Physiol Genomics 2013; 45:720-8. [PMID: 23780848 PMCID: PMC3742914 DOI: 10.1152/physiolgenomics.00089.2013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Accepted: 06/14/2013] [Indexed: 12/14/2022] Open
Abstract
Many lines of evidence demonstrate that genetic variability contributes to chronic kidney disease susceptibility in humans as well as rodent models. Little progress has been made in discovering causal kidney disease genes in humans mainly due to genetic complexity. Here, we use a minimal congenic mapping strategy in the FHH (fawn hooded hypertensive) rat to identify Sorcs1 as a novel renal disease candidate gene. We investigated the hypothesis that genetic variation in Sorcs1 influences renal disease susceptibility in both rat and human. Sorcs1 is expressed in the kidney, and knocking out this gene in a rat strain with a sensitized genome background produced increased proteinuria. In vitro knockdown of Sorcs1 in proximal tubule cells impaired protein trafficking, suggesting a mechanism for the observed proteinuria in the FHH rat. Since Sorcs1 influences renal function in the rat, we went on to test this gene in humans. We identified associations between single nucleotide polymorphisms in SORCS1 and renal function in large cohorts of European and African ancestry. The experimental data from the rat combined with association results from different ethnic groups indicates a role for SORCS1 in maintaining proper renal function.
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Affiliation(s)
- Jozef Lazar
- Department of Dermatology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
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Doris PA. Genetic susceptibility to hypertensive renal disease. Cell Mol Life Sci 2012; 69:3751-63. [PMID: 22562581 PMCID: PMC3422437 DOI: 10.1007/s00018-012-0996-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2012] [Revised: 04/04/2012] [Accepted: 04/06/2012] [Indexed: 12/21/2022]
Abstract
Hypertensive renal disease occurs at increased frequency among the relatives of patients with this disease compared to individuals who lack a family history of disease. This suggests a heritable risk in which genetic variation may play a role. These observations have motivated a search for genetic variation contributing to this risk in both experimental animal models and in human populations. Studies of animal models indicate the capacity of natural genetic variants to contribute to disease risk and have produced a few insights into the disease mechanism. In its current phase, human population genetic studies have sought to associate genetic variation with disease in large populations by testing genotypes at a large number of common genetic variations in the genome, expecting that common genetic variants contributing to renal disease risk will be identified. These genome-wide association studies (GWAS) have been productive and are a clear technical success; they have also identified narrowly defined loci and genes containing variation contributing to disease risk. Further extension and refinement of these GWAS are likely to extend this success. However, it is also clear that few additional variants with substantial effects accounting for the greatest part of heritability will be uncovered by GWAS. This raises an interesting biological question regarding where the remaining unaccounted heritable risk may be located. At present, much consideration is being given to this question and to the challenge of testing hypotheses that lead from the various alternative mechanisms under consideration. One result of the progress of GWAS is likely to be a renewed interest in mechanisms by which related individuals can share and transmit traits independently of Mendelian inheritance. This paper reviews the current progress in this area and considers other mechanisms by which familial aggregation of risk for renal disease may arise.
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Affiliation(s)
- Peter A Doris
- Institute of Molecular Medicine, University of Texas HSC at Houston, Houston, TX 77030, USA.
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Schulz A, Kreutz R. Mapping genetic determinants of kidney damage in rat models. Hypertens Res 2012; 35:675-94. [DOI: 10.1038/hr.2012.77] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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O'Meara CC, Lazar J, Hoffman M, Moreno C, Jacob HJ. Refined mapping of the renal failure RF-3 quantitative trait locus. J Am Soc Nephrol 2010; 22:518-25. [PMID: 21127141 DOI: 10.1681/asn.2010060661] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Rf-3, a quantitative trait locus (QTL) on rat chromosome 3, affects the development of CKD in Fawn-Hooded Hypertensive (FHH) rats. This QTL spans 110 Mb and approximately 1400 genes; therefore, narrowing the position of this locus is necessary to elucidate potential candidate genes. Here, we used congenic models and comparative genomics to refine the Rf-3 candidate region. We generated congenic lines carrying smaller intervals (subcongenics) of the Rf-3 region and used these lines to reduce the Rf-3 candidate region by 94% (to 7.1 Mb). We used comparative genomics to identify QTL for both nephropathy and albuminuria in the syntenic region of this interval for both human and mouse. We also used the overlapping homologous regions to reduce the number of likely positional candidate genes to 13 known or predicted genes. By combining congenic models and cross-species studies, we narrowed the list of candidate genes to a level that we could sequence the whole interval to further identify the causative gene in future studies.
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Affiliation(s)
- Caitlin C O'Meara
- Human and Molecular Genetics Center, Department of Physiology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
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Garrett MR, Pezzolesi MG, Korstanje R. Integrating human and rodent data to identify the genetic factors involved in chronic kidney disease. J Am Soc Nephrol 2010; 21:398-405. [PMID: 20133484 PMCID: PMC4473253 DOI: 10.1681/asn.2009080881] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
The increasing numbers of patients with chronic kidney disease combined with no satisfying interventions for preventing or curing the disease emphasize the need to better understand the genes involved in the initiation and progression of complex renal diseases, their interactions with other host genes, and the environment. Linkage and association studies in human, rat, and mouse have been successful in identifying genetic loci for various disease-related phenotypes but have thus far not been very successful identifying underlying genes. The purpose of this review is to summarize the progress in human, rat, and mouse genetic studies to show the concordance between the loci among the different species. The collective utilization of human and nonhuman mammalian datasets and resources can lead to a more rapid narrowing of disease loci and the subsequent identification of candidate genes. In addition, genes identified through these methods can be further characterized and investigated for interactions using animal models, which is not possible in humans.
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Affiliation(s)
- Michael R. Garrett
- *Department of Medicine and Kidney Disease Center, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Marcus G. Pezzolesi
- The Research Division, Joslin Diabetes Center, and Harvard Medical School, Boston, Massachusetts; and
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Kim K, Warden CH, Griffey SM, Vilches-Moure JG, Hansen S, Cuppen E, Nijman IJ, Chiu S, Stern JS. Genes unlinked to the leptin receptor influence urinary albumin excretion in obese Zucker rats. Physiol Genomics 2010; 41:297-305. [PMID: 20159938 DOI: 10.1152/physiolgenomics.90367.2008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We have previously shown that 90% of outbred obese Zucker Lepr(fa/fa) rats die prematurely of renal disease. Thus, renal disease in obese Zucker Lepr(fa/fa) rats may be caused by the LEPR mutation on chromosome 5, by the obesity, or it may be influenced by Zucker susceptibility alleles of genes on other chromosomes. We have searched for susceptibility genes on other chromosomes using urinary albumin excretion (UAE) as an early indicator of altered renal function in a backcross of (Brown Norway × inbred Zucker) F1 × inbred Zucker, which we name the BZZ cross. We killed 237 BZZ backcross animals at 15 wk of age. All included animals were homozygous for the fatty mutation of LEPR and were obese. Urinary creatinine measurements were used to calculate the albumin-to-creatinine ratio (ACR). We identified direct effect quantitative trait loci (QTLs) for UAE and ACR on chromosome 1 (LOD scores = 3.6 and 2.86, respectively) in males, and chromosome 4 (LOD score = 2.9) in females. Significant QTLs were identified for left kidney weight for females on chromosomes 3 and 12. We also demonstrated that kidneys from 15 wk old obese inbred Zucker rats already show evidence of kidney pathology: tubular dilation, proteinaceous fluid accumulation, evidence for inflammation, and mild mesangial and tubular membrane basement membrane thickening. Both lean Zucker rats and the Brown Norway rats showed no evidence for these changes. Thus, by removing the influence of the Lepr(fa/fa) mutation from analysis we have identified UAE QTLs unlinked to LEPR.
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Koeners MP, Braam B, van der Giezen DM, Goldschmeding R, Joles JA. A perinatal nitric oxide donor increases renal vascular resistance and ameliorates hypertension and glomerular injury in adult fawn-hooded hypertensive rats. Am J Physiol Regul Integr Comp Physiol 2008; 294:R1847-55. [PMID: 18417652 DOI: 10.1152/ajpregu.00073.2008] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Enhancing perinatal nitric oxide (NO) availability persistently reduces blood pressure in spontaneously hypertensive rats. We hypothesize that this approach can be generalized to other models of genetic hypertension, for instance those associated with renal injury. Perinatal exposure to the NO donor molsidomine was studied in fawn-hooded hypertensive (FHH) rats, a model of mild hypertension, impaired preglomerular resistance, and progressive renal injury. Perinatal molsidomine increased urinary NO metabolite excretion at 8 wk of age, i.e., 4 wk after treatment was stopped (P < 0.05). Systolic blood pressure was persistently reduced after molsidomine (42-wk females: 118 +/- 3 vs. 141 +/- 5 and 36-wk males: 139 +/- 4 vs. 158 +/- 4 mmHg; both P < 0.001). Perinatal treatment decreased glomerular filtration rate (P < 0.05) and renal blood flow (P < 0.01) and increased renal vascular resistance (P < 0.05), without affecting filtration fraction, suggesting persistently increased preglomerular resistance. At 4 wk of age natriuresis was transiently increased by molsidomine (P < 0.05). Molsidomine decreased glomerulosclerosis (P < 0.05). Renal blood flow correlated positively with glomerulosclerosis in control (P < 0.001) but not in perinatally treated FHH rats. NO dependency of renal vascular resistance was increased by perinatal molsidomine. Perinatal enhancement of NO availability can ameliorate development of hypertension and renal injury in FHH rats. Paradoxically, glomerular protection by perinatal exposure to the NO donor molsidomine may be due to persistently increased preglomerular resistance. The mechanisms by which increased perinatal NO availability can persistently reprogram kidney function and ameliorate hypertension deserve further study.
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Affiliation(s)
- Maarten P Koeners
- Department of Nephrology and Hypertension F03.223, University Medical Center Utrecht, Utrecht, The Netherlands
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Kato N, Watanabe Y, Ohno Y, Inoue T, Kanno Y, Suzuki H, Okada H. Mapping quantitative trait loci for proteinuria-induced renal collagen deposition. Kidney Int 2008; 73:1017-23. [PMID: 18305463 DOI: 10.1038/ki.2008.7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The progression of chronic kidney disease is a complex process influenced by genetic factors. Proteinuria is a predictor of functional deterioration and an accelerator of disease progression through renal parenchymal damage and interstitial fibrosis. To determine genetic components that might mediate renal fibrosis due to proteinuria, we mapped loci influencing the phenotype of two mouse strains differing in proteinuria-induced renal type I collagen (COLI) deposition. Collagen I deposition in 129S1/svImJ and C57BL/6J mice differs significantly among tested strains. We backcrossed 120 hemi-nephrectomized (129S1/svImJ x C57BL/6J) F1 x 129S1/svImJ backcrossed mice loaded with bovine serum albumin giving rise to proteinuria and renal COLI deposition. Quantitative trait loci (QTL) mapping was performed and our analysis identified one suggestive linkage for renal COLI deposition peaking at 87 cM near D2Mit224 (logarithm of odds: 2.41) on Chr 2. In silico analysis uncovered nine candidate genes. Hence, although more studies are needed, these QTL provide an initial cue to subsequent gene discovery, which might help unravel the genetics of renal fibrosis.
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Affiliation(s)
- N Kato
- Department of Nephrology, Research Center for Genomic Medicine, Saitama Medical University, Saitama, Japan
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Abstract
PURPOSE OF REVIEW Autoregulation of renal blood flow has traditionally been considered to stabilize glomerular filtration, and thus tubular load, in the face of blood pressure fluctuations. This view arose because of the contribution of tubuloglomerular feedback, which senses distal tubular fluid composition, to regulation and autoregulation of renal blood flow. Studies have indicated a more important role for the myogenic mechanism. It has been proposed that the 'purpose' of autoregulation is to defend glomerular structure. Both these views may be incomplete because neither takes into consideration the complex interactions between tubuloglomerular feedback and the myogenic mechanism and among nephrons whose afferent arterioles derived from a common interlobular artery. RECENT FINDINGS Recent findings indicate that it is now indisputable that effective autoregulation is necessary for defense of glomerular structure. Extensive modulation of the myogenic mechanism by tubuloglomerular feedback has been shown using a variety of experimental designs that have illuminated one pathway (neuronal nitric oxide synthase at the macula densa) by which this occurs. SUMMARY These findings indicate that the myogenic mechanism can no longer be considered as a purely vascular mechanism in the kidney and instead receives information via tubuloglomerular feedback about the status of renal function.
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Affiliation(s)
- William A Cupples
- Centre for Biomedical Research, Department of Biology, University of Victoria, Victoria, British Columbia, Canada.
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Abstract
The kidney displays highly efficient autoregulation so that under steady-state conditions renal blood flow (RBF) is independent of blood pressure over a wide range of pressure. Autoregulation occurs in the preglomerular microcirculation and is mediated by two, perhaps three, mechanisms. The faster myogenic mechanism and the slower tubuloglomerular feedback contribute both directly and interactively to autoregulation of RBF and of glomerular capillary pressure. Multiple experiments have been used to study autoregulation and can be considered as variants of two basic designs. The first measures RBF after multiple stepwise changes in renal perfusion pressure to assess how a biological condition or experimental maneuver affects the overall pressure-flow relationship. The second uses time-series analysis to better understand the operation of multiple controllers operating in parallel on the same vascular smooth muscle. There are conceptual and experimental limitations to all current experimental designs so that no one design adequately describes autoregulation. In particular, it is clear that the efficiency of autoregulation varies with time and that most current techniques do not adequately address this issue. Also, the time-varying and nonadditive interaction between the myogenic mechanism and tubuloglomerular feedback underscores the difficulty of dissecting their contributions to autoregulation. We consider the modulation of autoregulation by nitric oxide and use it to illustrate the necessity for multiple experimental designs, often applied iteratively.
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Affiliation(s)
- William A Cupples
- Centre for Biomedical Research and Dept. of Biology, Univ. of Victoria, PO Box 3020, STN CSC, Victoria, BC, Canada.
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Current World Literature. Curr Opin Nephrol Hypertens 2007; 16:52-7. [PMID: 17143072 DOI: 10.1097/mnh.0b013e32801271d6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Ways JA, Smith BM, Barbato JC, Ramdath RS, Pettee KM, DeRaedt SJ, Allison DC, Koch LG, Lee SJ, Cicila GT. Congenic strains confirm aerobic running capacity quantitative trait loci on rat chromosome 16 and identify possible intermediate phenotypes. Physiol Genomics 2006; 29:91-7. [PMID: 17179209 DOI: 10.1152/physiolgenomics.00027.2006] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We previously identified two inbred rat strains divergent for treadmill aerobic running capacity (ARC), the low-performing Copenhagen (COP) and the high-performing DA rats, and used an F(2)(COPxDA) population to identify ARC quantitative trait loci (QTLs) on rat chromosome 16 (RNO16) and the proximal portion of rat chromosome 3 (RNO3). Two congenic rat strains were bred to further investigate these ARC QTLs by introgressing RNO16 and the proximal portion of RNO3 from DA rats into the genetic background of COP rats and were named COP.DA(chr 16) and COP.DA(chr 3), respectively. COP.DA(chr 16) rats had significantly greater ARC compared with COP rats (696.7 +/- 38.2 m vs. 571.9 +/- 27.5 m, P = 0.03). COP.DA(chr 3) rats had increased, although not significant, ARC compared with COP rats (643.6 +/- 40.9 m vs. 571.9 +/- 27.5 m). COP.DA(chr 16) rats had significantly greater subcutaneous abdominal fat, as well as decreased fasting triglyceride levels, compared with COP rats (P < 0.05), indicating that genes responsible for strain differences in fat metabolism are also located on RNO16. While this colocalization of QTLs may be coincidental, it is also possible that these differences in energy balance may be associated with the superior running performance of COP.DA(chr 16) consomic rats.
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Affiliation(s)
- Justin A Ways
- Departments of Physiology, Pharmacology, Metabolism, and Cardiovascular Sciences, University of Toledo College of Medicine, Toledo, OH 43614, USA
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van Dijk SJ, Specht PAC, Lazar J, Jacob HJ, Provoost AP. Absence of an Interaction between the Rf-1 and Rf-5 QTLs Influencing Susceptibility to Renal Damage in Rats. ACTA ACUST UNITED AC 2006; 104:e96-e102. [PMID: 16837819 DOI: 10.1159/000094548] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2005] [Accepted: 04/26/2006] [Indexed: 11/19/2022]
Abstract
BACKGROUND Previous studies showed that combining the Rf-1 and Rf-3 or Rf-4 QTLs of FHH induced synergistic interactions markedly enhancing renal susceptibility. The present study aimed to determine the presence of such interaction between the Rf-1 and Rf-5 QTLs. METHODS Renal damage susceptibility was assessed in Rf-1B, Rf-1B+5, Rf-1B+4 congenics and ACI control rats in four situations: two-kidney control (2K), unilateral nephrectomy (UNX), L-NAME-induced hypertension (2K+L-NAME) and UNX+L-NAME. Albuminuria (UAV) and systolic blood pressure (SBP) were measured during 18 weeks of follow-up. In separate experiments, renal autoregulation was assessed in 2K rats. RESULTS In all four situations, Rf-1B+4 rats developed more severe UAV than ACI, Rf-1B and Rf-1B+5. There were no significant differences in UAV between Rf-1B and Rf-1B+5 rats. In the 2K and UNX situation no differences in SBP were noted between all four strains. With 2K+L-NAME and UNX+L-NAME treatment, SBP in double congenics was higher than that of ACI and Rf-1B rats. Renal autoregulation was similarly impaired in all three congenic strains. CONCLUSION We conclude that the Rf-5 region, alone or in the presence of Rf-1B, does not affect the development of renal damage. We cannot substantiate that the Rf-5 region contains genes influencing renal damage susceptibility.
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Affiliation(s)
- Sabine J van Dijk
- Department of Paediatric Surgery, Erasmus MC, Rotterdam, The Netherlands
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