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Forster CM, White CA, Turner ME, Norman PA, Ward EC, Hopman WM, Adams MA, Holden RM. Circulating Levels of Dickkopf-Related Protein 1 Decrease as Measured GFR Declines and Are Associated with PTH Levels. Am J Nephrol 2020; 51:871-880. [PMID: 33238271 DOI: 10.1159/000511658] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [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: 06/10/2020] [Accepted: 09/16/2020] [Indexed: 11/19/2022]
Abstract
BACKGROUND The Wnt/β-catenin pathway has been implicated in the development of adynamic bone disease in early-stage chronic kidney disease (CKD). Dickkopf-related protein 1 (DKK1) and sclerostin are antagonists of the Wnt/β-catenin pathway yet have not been widely used as clinical indicators of bone disease. This study characterized levels of DKK1, sclerostin, and other biomarkers of mineral metabolism in participants across a spectrum of inulin-measured glomerular filtration rate (GFR). METHODS GFR was measured by urinary inulin clearance (mGFR) in 90 participants. Blood samples were obtained for measurement of circulating DKK1, sclerostin, fibroblast growth factor 23 (FGF-23), parathyroid hormone (PTH), calcium, phosphate, α-klotho, and vitamin D metabolites including 25-hydroxyvitamin D3 and 1,25-dihydroxyvitamin D3. Spearman correlations and linear regressions were used where appropriate to examine the associations between measured values. RESULTS The median [IQR] age was 64 years [53.0-71.0], and the median [IQR] mGFR was 32.6 [21.7-60.6] mL/min. DKK1 decreased (r = 0.6, p < 0.001) and sclerostin increased (r = -0.4, p < 0.001) as kidney function declined, and both were associated with phosphate, PTH, FGF-23, and 1,25-dihydroxyvitamin D3 in the unadjusted analysis. After adjustment for age and mGFR, DKK1 remained significantly associated with PTH. CONCLUSION The results of this study demonstrate opposing trends in Wnt/β-catenin pathway inhibitors, DKK1 and sclerostin, as mGFR declines. Unlike sclerostin, DKK1 levels decreased significantly as mGFR declined and was independently associated with PTH. Future studies should determine whether measurement of Wnt signaling inhibitors may be useful in predicting bone histomorphometric findings and important clinical outcomes in patients with CKD.
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Affiliation(s)
- Corey M Forster
- Department of Biomedical and Molecular Science, Queen's University, Kingston, Ontario, Canada
- Department of Medicine, Queen's University, Kingston, Ontario, Canada
| | - Christine A White
- Department of Medicine, Queen's University, Kingston, Ontario, Canada
| | - Mandy E Turner
- Department of Biomedical and Molecular Science, Queen's University, Kingston, Ontario, Canada
| | - Patrick A Norman
- Kingston General Health Research Institute, Kingston General Hospital, Kingston, Ontario, Canada
| | - Emilie C Ward
- Department of Biomedical and Molecular Science, Queen's University, Kingston, Ontario, Canada
| | - Wilma M Hopman
- Kingston General Health Research Institute, Kingston General Hospital, Kingston, Ontario, Canada
- Department of Public Health Sciences, Queen's University, Kingston, Ontario, Canada
| | - Michael A Adams
- Department of Biomedical and Molecular Science, Queen's University, Kingston, Ontario, Canada
| | - Rachel M Holden
- Department of Biomedical and Molecular Science, Queen's University, Kingston, Ontario, Canada,
- Department of Medicine, Queen's University, Kingston, Ontario, Canada,
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Drabińska N, Jarocka-Cyrta E, Ratcliffe NM, Krupa-Kozak U. The Profile of Urinary Headspace Volatile Organic Compounds After 12-Week Intake of Oligofructose-Enriched Inulin by Children and Adolescents with Celiac Disease on a Gluten-Free Diet: Results of a Pilot, Randomized, Placebo-Controlled Clinical Trial. Molecules 2019; 24:E1341. [PMID: 30959740 PMCID: PMC6479364 DOI: 10.3390/molecules24071341] [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] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 04/01/2019] [Accepted: 04/04/2019] [Indexed: 12/26/2022] Open
Abstract
The concentration of volatile organic compounds (VOCs) can inform about the metabolic condition of the body. In the small intestine of untreated persons with celiac disease (CD), chronic inflammation can occur, leading to nutritional deficiencies, and consequently to functional impairments of the whole body. Metabolomic studies showed differences in the profile of VOCs in biological fluids of patients with CD in comparison to healthy persons; however, there is scarce quantitative and nutritional intervention information. The aim of this study was to evaluate the effect of the supplementation of a gluten-free diet (GFD) with prebiotic oligofructose-enriched inulin (Synergy 1) on the concentration of VOCs in the urine of children and adolescents with CD. Twenty-three participants were randomized to the group receiving Synergy 1 (10 g per day) or placebo for 12 weeks. Urinary VOCs were analyzed using solid-phase microextraction and gas chromatography⁻mass spectrometry. Sixteen compounds were identified and quantified in urine samples. The supplementation of GFD with Synergy 1 resulted in an average concentration drop (36%) of benzaldehyde in urine samples. In summary, Synergy 1, applied as a supplement of GFD for 12 weeks had a moderate impact on the VOC concentrations in the urine of children with CD.
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Affiliation(s)
- Natalia Drabińska
- Department of Chemistry and Biodynamics of Food, Institute of Animal Reproduction and Food Research of Polish Academy of Sciences, Tuwima 10 Str., 10-748 Olsztyn, Poland.
| | - Elżbieta Jarocka-Cyrta
- Department of Pediatrics, Gastroenterology, and Nutrition, Collegium Medicum, University of Warmia & Mazury, Oczapowskiego 2 Str., 10-719 Olsztyn, Poland.
| | - Norman Mark Ratcliffe
- Institute of Biosensor Technology, the University of the West of England, University of the West of England, Coldharbour Lane, Frenchay, Bristol BS16 1QY, UK.
| | - Urszula Krupa-Kozak
- Department of Chemistry and Biodynamics of Food, Institute of Animal Reproduction and Food Research of Polish Academy of Sciences, Tuwima 10 Str., 10-748 Olsztyn, Poland.
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den Bakker E, Gemke R, van Wijk JAE, Hubeek I, Stoffel-Wagner B, Bökenkamp A. Combining GFR estimates from cystatin C and creatinine-what is the optimal mix? Pediatr Nephrol 2018; 33:1553-1563. [PMID: 29774462 DOI: 10.1007/s00467-018-3973-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 04/29/2018] [Accepted: 04/30/2018] [Indexed: 11/26/2022]
Abstract
BACKGROUND Combining estimated glomerular filtration rate (eGFR) equations based on creatinine and cystatin C has been shown to improve the accuracy of GFR estimation. This study aims to optimize this strategy for height-independent GFR estimation in children. METHODS Retrospective study of 408 inulin clearance tests with simultaneous International Federation of Clinical Chemistry-calibrated measurements of creatinine, cystatin C, and urea in children (mean age 12.5 years, GFR 91.2 ml/min/1.73m2) comparing the arithmetic (meanarith) and geometric means (meangeom) of a height-independent creatinine-based (full age spectrum, based on age (FASage)) and a cystatin C-based equation (FAScys), with the complex height-dependent CKiD3 equation incorporating gender, height, cystatin C, creatinine, and urea. RESULTS Meangeom had a P30 accuracy of 89.2% compared to meanarith 87.7% (p = 0.030) as well as lower bias and %precision error and performed almost as well as CKiD3 (P30 accuracy 90.9%). Modifying the weight of FASage and FAScys when calculating the means showed that an equal contribution was most accurate in most patients. In spina bifida patients, FAScys alone outperformed any combination. Malignancy or nephritis patients had slightly higher accuracy with weighted means favoring cystatin C or creatinine, respectively. Disagreement between FAScys and FASage was inversely correlated with the accuracy of meangeom. When disagreement exceeded 40%, application of weighted means based on diagnosis improved the performance of eGFR. CONCLUSIONS In the absence of height data, the optimal strategy for estimating GFR in children is by using the geometric mean of FASage and FAScys. When there is large disagreement between the two, weighted means based on diagnosis improve accuracy.
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Affiliation(s)
- Emil den Bakker
- Department of Pediatrics, VU University Medical Center, Amsterdam, The Netherlands
| | - Reinoud Gemke
- Department of Pediatrics, VU University Medical Center, Amsterdam, The Netherlands
| | - Joanna A E van Wijk
- Department of Pediatrics, VU University Medical Center, Amsterdam, The Netherlands
- Department of Pediatric Nephrology, VU University Medical Center, De Boelelaan 1118, NL-1081 HV, Amsterdam, The Netherlands
| | - Isabelle Hubeek
- Department of Clinical Chemistry, VU University Medical Center, Amsterdam, The Netherlands
| | - Birgit Stoffel-Wagner
- Department of Clinical Chemistry and Clinical Pharmacology, University Clinics, Bonn, Germany
| | - Arend Bökenkamp
- Department of Pediatrics, VU University Medical Center, Amsterdam, The Netherlands.
- Department of Pediatric Nephrology, VU University Medical Center, De Boelelaan 1118, NL-1081 HV, Amsterdam, The Netherlands.
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Kumar V, Yadav AK, Yasuda Y, Horio M, Kumar V, Sahni N, Gupta KL, Matsuo S, Kohli HS, Jha V. Existing creatinine-based equations overestimate glomerular filtration rate in Indians. BMC Nephrol 2018; 19:22. [PMID: 29390980 PMCID: PMC5796440 DOI: 10.1186/s12882-018-0813-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [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: 07/03/2017] [Accepted: 01/04/2018] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Accurate estimation of glomerular filtration rate (GFR) is important for diagnosis and risk stratification in chronic kidney disease and for selection of living donors. Ethnic differences have required correction factors in the originally developed creatinine-based GFR estimation equations for populations around the world. Existing equations have not been validated in the vegetarian Indian population. We examined the performance of creatinine and cystatin-based GFR estimating equations in Indians. METHODS GFR was measured by urinary clearance of inulin. Serum creatinine was measured using IDMS-traceable Jaffe's and enzymatic assays, and cystatin C by colloidal gold immunoassay. Dietary protein intake was calculated by measuring urinary nitrogen appearance. Bias, precision and accuracy were calculated for the eGFR equations. RESULTS A total of 130 participants (63 healthy kidney donors and 67 with CKD) were studied. About 50% were vegetarians, and the remainder ate meat 3.8 times every month. The average creatinine excretion were 14.7 mg/kg/day (95% CI: 13.5 to 15.9 mg/kg/day) and 12.4 mg/kg/day (95% CI: 11.2 to 13.6 mg/kg/day) in males and females, respectively. The average daily protein intake was 46.1 g/day (95% CI: 43.2 to 48.8 g/day). The mean mGFR in the study population was 51.66 ± 31.68 ml/min/1.73m2. All creatinine-based eGFR equations overestimated GFR (p < 0.01 for each creatinine based eGFR equation). However, eGFR by CKD-EPICys was not significantly different from mGFR (p = 0.38). The CKD-EPICys exhibited lowest bias [mean bias: -3.53 ± 14.70 ml/min/1.73m2 (95% CI: -0.608 to -0.98)] and highest accuracy (P30: 74.6%). The GFR in the healthy population was 79.44 ± 20.19 (range: 41.90-134.50) ml/min/1.73m2. CONCLUSION Existing creatinine-based GFR estimating equations overestimate GFR in Indians. An appropriately powered study is needed to develop either a correction factor or a new equation for accurate assessment of kidney function in the Indian population.
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Affiliation(s)
- Vivek Kumar
- Department of Nephrology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Ashok Kumar Yadav
- Department of Nephrology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Yoshinari Yasuda
- Department of Nephrology, Nagoya University Graduate School of Medicine, Nagoya, Japan
- Department of CKD Initiatives, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Masaru Horio
- Division of Health Sciences, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Vinod Kumar
- Department of Nephrology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Nancy Sahni
- Department of Dietitics, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Krishan L. Gupta
- Department of Nephrology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Seiichi Matsuo
- Department of Nephrology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Harbir Singh Kohli
- Department of Nephrology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Vivekanand Jha
- Department of Nephrology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
- George Institute for Global Health, 311-312, Elegance Tower, Plot No. 8, Jasola District Centre, New Delhi, 110025 India
- University of Oxford, London, UK
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Yukawa S, Watanabe D, Uehira T, Shirasaka T. Clinical benefits of using inulin clearance and cystatin C for determining glomerular filtration rate in HIV-1-infected individuals treated with dolutegravir. J Infect Chemother 2017; 24:199-205. [PMID: 29150412 DOI: 10.1016/j.jiac.2017.10.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [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: 08/31/2017] [Revised: 10/10/2017] [Accepted: 10/13/2017] [Indexed: 11/19/2022]
Abstract
INTRODUCTION Dolutegravir may inhibit creatinine transporters in renal tubules and elevate serum creatinine levels. We investigated the usefulness of glomerular filtration rate (GFR) measured using inulin clearance (Cin), creatinine clearance (Ccr), and estimated GFR based on both serum creatinine (eGFRcre) and serum cystatin C (eGFRcys). PATIENTS & METHODS HIV-1-infected Japanese patients with suppressed viremia and whose antiretroviral drug was switched to dolutegravir from other drugs were included (n = 108, Study 1). We compared eGFRcre and eGFRcys at the start and after 48 weeks of dolutegravir administration. For the patients providing consent, we measured Cin and Ccr (n = 15, Study 2). We assessed biases and accuracy and compared Cin with eGFRcre, eGFRcys, and Ccr. RESULTS There were no differences in serum cystatin C and eGFRcys between baseline and at 48 weeks. Moreover, eGFRcre was significantly less accurate (within 30% of measured GFR) than both eGFRcys and Ccr (40% accuracy compared to 93% and 93%, respectively). eGFRcys was significantly less biased than eGFRcre and Ccr (p < 0.0001, p = 0.00036, respectively). No significant difference between Cin and eGFRcys was observed. eGFRcys was significantly correlated with Cin (γ = 0.85, p < 0.0001). CONCLUSIONS eGFRcys provided the most precise estimate and most closely approximate Cin in HIV-1-infected Japanese patients with suppressed viremia treated with dolutegravir. We demonstrated clinical benefits of inulin clearance and eGFRcys. This is the first study performing inulin clearance for HIV-1-infected individuals and to show data for eGFRcys from a large cohort following a switch to dolutegravir from other antiretroviral agents.
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Affiliation(s)
- Satomi Yukawa
- Department of Advanced Medicine for HIV Infection, Osaka University Graduate School of Medicine, Osaka, Japan; Department of Infectious Diseases, National Hospital Organization Osaka National Hospital, Osaka, Japan.
| | - Dai Watanabe
- Department of Advanced Medicine for HIV Infection, Osaka University Graduate School of Medicine, Osaka, Japan; AIDS Medical Center, National Hospital Organization Osaka National Hospital, Osaka, Japan
| | - Tomoko Uehira
- Department of Infectious Diseases, National Hospital Organization Osaka National Hospital, Osaka, Japan
| | - Takuma Shirasaka
- Department of Advanced Medicine for HIV Infection, Osaka University Graduate School of Medicine, Osaka, Japan; AIDS Medical Center, National Hospital Organization Osaka National Hospital, Osaka, Japan
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Abstract
Glomerular filtration rate (GFR) is the best index for kidney function in health and disease. Knowledge of the GFR is essential for the detection (diagnosis) and monitoring of renal function during disease progression and for ensuring correct medication doses. Inulin clearance (plasma or urine) is currently considered to be the gold standard for measuring GFR, but in clinical practice the measurement of other exogenous filtration markers from the plasma often replaces that of inulin clearance. Different protocols can be used to determine the area under the plasma disappearance curve, and an understanding of these methods is important. GFR can also be estimated by GFR equations (eGFR), which are most often used in clinical practice because they only require a knowledge of the serum creatinine or cystatin C level and demographic information. eGFR equations are easy to use but they do have their limitations, and it is important to know how these equations were derived and in which circumstances they can be used most accurately. The aim of this review is to explain how GFR can be measured using the renal clearance and the plasma clearance method and which eGFR equations can be applied to children, as well as how and when these equations can be used in clinical practice.
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Affiliation(s)
- Hans Pottel
- Department of Public Health and Primary Care, Campus Kulak Kortrijk, KU Leuven, Etienne Sabbelaan 53, 8500, Kortrijk, Belgium.
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Li K, Zou J, Ye Z, Di J, Han X, Zhang H, Liu W, Ren Q, Zhang P. Effects of Bariatric Surgery on Renal Function in Obese Patients: A Systematic Review and Meta Analysis. PLoS One 2016; 11:e0163907. [PMID: 27701452 PMCID: PMC5049777 DOI: 10.1371/journal.pone.0163907] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [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: 06/20/2016] [Accepted: 09/18/2016] [Indexed: 01/06/2023] Open
Abstract
Background Obesity is an independent risk factor of development and progression of chronic kidney disease (CKD). Data on the benefits of bariatric surgery in obese patients with impaired kidney function have been conflicting. Objective To explore whether there is improvement in glomerular filtration rate (GFR), proteinuria or albuminuria after bariatric surgery. Methods We comprehensively searched the databases of MEDLINE, Embase, web of science and Cochrane for randomized, controlled trials and observational studies that examined bariatric surgery in obese subjects with impaired kidney function. Outcomes included the pre- and post-bariatric surgery GFR, proteinuria and albuminuria. In obese patients with hyperfiltration, we draw conclusions from studies using measured GFR (inulin or iothalamate clearance) unadjusted for BSA only. Study quality was evaluated using the Newcastle-Ottawa Scale. Results 32 observational studies met our inclusion criteria, and 30 studies were included in the meta-analysis. No matter in dichotomous data or in dichotomous data, there were statistically significant reduction in hyperfiltration, albuminuria and proteinuria after bariatric surgery. Limitations The main limitation of this meta-analysis is the lack of randomized controlled trials (RCTs). Another limitation is the lack of long-term follow-up. Conclusions Bariatric surgery could prevent further decline in renal function by reducing proteinuria, albuminuria and improving glomerular hyperfiltration in obese patients with impaired renal function. However, whether bariatric surgery reverses CKD or delays ESRD progression is still in question, large, randomized prospective studies with a longer follow-up are needed.
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Affiliation(s)
- Kun Li
- Department of General Surgery, Huadong Hospital Affiliated to Fudan University, Shanghai, China
- * E-mail:
| | - Jianan Zou
- Department of Nephrology, Huadong Hospital Affiliated to Fudan University, Shanghai, China
| | - Zhibin Ye
- Department of Nephrology, Huadong Hospital Affiliated to Fudan University, Shanghai, China
| | - Jianzhong Di
- Department of General Surgery, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Shanghai, China
| | - Xiaodong Han
- Department of General Surgery, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Shanghai, China
| | - Hongwei Zhang
- Department of General Surgery, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Shanghai, China
| | - Weijie Liu
- Department of General Surgery, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Shanghai, China
| | - Qinggui Ren
- Department of General Surgery, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Shanghai, China
| | - Pin Zhang
- Department of General Surgery, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Shanghai, China
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Selistre L, Rabilloud M, Cochat P, de Souza V, Iwaz J, Lemoine S, Beyerle F, Poli-de-Figueiredo CE, Dubourg L. Comparison of the Schwartz and CKD-EPI Equations for Estimating Glomerular Filtration Rate in Children, Adolescents, and Adults: A Retrospective Cross-Sectional Study. PLoS Med 2016; 13:e1001979. [PMID: 27023756 PMCID: PMC4811544 DOI: 10.1371/journal.pmed.1001979] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 02/09/2016] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Estimating kidney glomerular filtration rate (GFR) is of utmost importance in many clinical conditions. However, very few studies have evaluated the performance of GFR estimating equations over all ages and degrees of kidney impairment. We evaluated the reliability of two major equations for GFR estimation, the CKD-EPI and Schwartz equations, with urinary clearance of inulin as gold standard. METHODS AND FINDINGS The study included 10,610 participants referred to the Renal and Metabolic Function Exploration Unit of Edouard Herriot Hospital (Lyon, France). GFR was measured by urinary inulin clearance (only first measurement kept for analysis) then estimated with isotope dilution mass spectrometry (IDMS)-traceable CKD-EPI and Schwartz equations. The participants' ages ranged from 3 to 90 y, and the measured GFRs from 3 to 160 ml/min/1.73 m2. A linear mixed-effects model was used to model the bias (mean ratio of estimated GFR to measured GFR). Equation reliability was also assessed using precision (interquartile range [IQR] of the ratio) and accuracy (percentage of estimated GFRs within the 10% [P10] and 30% [P30] limits above and below the measured GFR). In the whole sample, the mean ratio with the CKD-EPI equation was significantly higher than that with the Schwartz equation (1.17 [95% CI 1.16; 1.18] versus 1.08 [95% CI 1.07; 1.09], p < 0.001, t-test). At GFR values of 60-89 ml/min/1.73 m2, the mean ratios with the Schwartz equation were closer to 1 than the mean ratios with the CKD-EPI equation whatever the age class (1.02 [95% CI 1.01; 1.03] versus 1.15 [95% CI 1.13; 1.16], p < 0.001, t-test). In young adults (18-40 y), the Schwartz equation had a better precision and was also more accurate than the CKD-EPI equation at GFR values under 60 ml/min/1.73 m2 (IQR: 0.32 [95% CI 0.28; 0.33] versus 0.40 [95% CI 0.36; 0.44]; P30: 81.4 [95% CI 78.1; 84.7] versus 63.8 [95% CI 59.7; 68.0]) and also at GFR values of 60-89 ml/min/1.73 m2. In all patients aged ≥65 y, the CKD-EPI equation performed better than the Schwartz equation (IQR: 0.33 [95% CI 0.31; 0.34] versus 0.40 [95% CI 0.38; 0.41]; P30: 77.6 [95% CI 75.7; 79.5] versus 67.5 [95% CI 65.4; 69.7], respectively). In children and adolescents (2-17 y), the Schwartz equation was superior to the CKD-EPI equation (IQR: 0.23 [95% CI 0.21; 0.24] versus 0.33 [95% CI 0.31; 0.34]; P30: 88.6 [95% CI 86.7; 90.4] versus 29.4 [95% CI 26.8; 32.0]). This study is limited by its retrospective design, single-center setting with few non-white patients, and small number of patients with severe chronic kidney disease. CONCLUSIONS The results from this study suggest that the Schwartz equation may be more reliable than the CKD-EPI equation for estimating GFR in children and adolescents and in adults with mild to moderate kidney impairment up to age 40 y.
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Affiliation(s)
- Luciano Selistre
- Exploration Fonctionnelle Rénale et Métabolique, Groupement Hospitalier Est Hôpital Edouard Herriot, Hospices Civils de Lyon, Lyon, France
- Coordenação de Aperfeiçoamento do Pessoal de Nível Superior (CAPES), Brasilia, Brazil
- Programa de Pós-graduação em Medicina e Ciências da Saúde, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil
- Programa de Pós-graduação em Ciências da Saúde, Universidade de Caxias do Sul, Caxias do Sul, Brazil
- Service de Biostatistique, Hospices Civils de Lyon, Lyon, France
| | - Muriel Rabilloud
- Service de Biostatistique, Hospices Civils de Lyon, Lyon, France
- Université de Lyon, Lyon, France
- CNRS UMR 5558, Laboratoire de Biométrie et Biologie Evolutive, Equipe Biostatistique-Santé, Villeurbanne, France
| | - Pierre Cochat
- Université de Lyon, Lyon, France
- CNRS UMR 5558, Laboratoire de Biométrie et Biologie Evolutive, Equipe Biostatistique-Santé, Villeurbanne, France
- UMR 5305, Biologie Tissulaire et Ingénierie Thérapeutique, Université Claude Bernard, Lyon, France
- Centre de Référence des Maladies Rénales Rares, Service de Néphrologie et Rhumatologie Pédiatriques, Hospices Civils de Lyon, Lyon, France
| | - Vandréa de Souza
- Exploration Fonctionnelle Rénale et Métabolique, Groupement Hospitalier Est Hôpital Edouard Herriot, Hospices Civils de Lyon, Lyon, France
- Coordenação de Aperfeiçoamento do Pessoal de Nível Superior (CAPES), Brasilia, Brazil
- Programa de Pós-graduação em Ciências da Saúde, Universidade de Caxias do Sul, Caxias do Sul, Brazil
| | - Jean Iwaz
- Service de Biostatistique, Hospices Civils de Lyon, Lyon, France
- Université de Lyon, Lyon, France
- CNRS UMR 5558, Laboratoire de Biométrie et Biologie Evolutive, Equipe Biostatistique-Santé, Villeurbanne, France
| | - Sandrine Lemoine
- Exploration Fonctionnelle Rénale et Métabolique, Groupement Hospitalier Est Hôpital Edouard Herriot, Hospices Civils de Lyon, Lyon, France
- UMR 5305, Biologie Tissulaire et Ingénierie Thérapeutique, Université Claude Bernard, Lyon, France
- INSERM UMR 1060, Université Claude Bernard Lyon I, Lyon, France
| | - Françoise Beyerle
- Exploration Fonctionnelle Rénale et Métabolique, Groupement Hospitalier Est Hôpital Edouard Herriot, Hospices Civils de Lyon, Lyon, France
- Laboratoire de Biochimie et Biologie Moléculaire, Groupement Hospitalier Est Hôpital Edouard Herriot, Hospices Civils de Lyon, Lyon, France
| | - Carlos E. Poli-de-Figueiredo
- Programa de Pós-graduação em Medicina e Ciências da Saúde, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil
| | - Laurence Dubourg
- Exploration Fonctionnelle Rénale et Métabolique, Groupement Hospitalier Est Hôpital Edouard Herriot, Hospices Civils de Lyon, Lyon, France
- Université de Lyon, Lyon, France
- UMR 5305, Biologie Tissulaire et Ingénierie Thérapeutique, Université Claude Bernard, Lyon, France
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Passos MT, Nishida SK, Câmara NOS, Shimizu MH, Mastroianni-Kirsztajn G. Iohexol clearance for determination of glomerular filtration rate in rats induced to acute renal failure. PLoS One 2015; 10:e0123753. [PMID: 25875005 PMCID: PMC4395274 DOI: 10.1371/journal.pone.0123753] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [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: 10/29/2014] [Accepted: 03/02/2015] [Indexed: 11/18/2022] Open
Abstract
INTRODUCTION The glomerular filtration rate (GFR) is considered an especially important tool for the measurement of renal function. Inulin clearance (InCl) is the classic reference method for this purpose, although it is associated with a number of disadvantages; thus, other markers have been proposed, including iohexol. Determination of iohexol clearance (IoCl) has been established for clinical use; however, its application as a GFR marker in experimental rat models has not been reported. OBJECTIVES This study aims to standardize a methodology for the measurement of iohexol clearance and to evaluate its applicability as a marker of GFR in rats with induced toxic acute renal failure (ARF), using InCl as the gold standard. MATERIALS AND METHODS Twenty-six Wistar male rats (200-300 g) were divided into the following two groups: a control group (n=7) and an ARF group (n=19). ARF was induced by the subcutaneous administration of cisplatin (5 mg/kg); IoCl and InCl were determined simultaneously, and plasma creatinine (pCreat) dosage was measured colorimetrically. RESULTS The pCreat, InCl and IoCl levels were consistent with the expected values for the renal function ranges of the evaluated animals, and the IoCl and InCl levels were significantly correlated (r=0.792). An inverse moderate linear correlation between the IoCl and pCreat measurements (r=-0.587) and between the InCl and pCreat measurements (r=-0.722) were observed. CONCLUSION These results confirm a correlation between IoCl and the gold standard of GFR, InCl measurement. IoCl offers a relevant advantage over InCl because determination of the former allows the animal to live after the procedure.
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Affiliation(s)
- Michelle T. Passos
- Department of Medicine, Division of Nephrology, Federal University of Sao Paulo, Sao Paulo-SP, Brazil
| | - Sonia K. Nishida
- Department of Medicine, Division of Nephrology, Federal University of Sao Paulo, Sao Paulo-SP, Brazil
| | - Niels O. S. Câmara
- Department of Medicine, Division of Nephrology, Federal University of Sao Paulo, Sao Paulo-SP, Brazil
- Department of Immunology, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo-SP, Brazil
| | - Maria Heloisa Shimizu
- Department of Nephrology, University of Sao Paulo—School of Medicine, Sao Paulo-SP, Brazil
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Schück O, Teplan V, Maly J, Franekova J, Malinska H, Stollova M, Latova I, Urbanova J, Skibova J, Viklicky O. The relationship between estimated GFR based on the CKD-EPI formula and renal inulin clearance in potential kidney donors. Clin Nephrol 2014; 82:353-7. [PMID: 25345381 PMCID: PMC4928034 DOI: 10.5414/cn108341] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [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: 03/31/2014] [Accepted: 11/17/2014] [Indexed: 11/18/2022] Open
Abstract
It is not yet clear whether or not renal function in the living donor can be sufficiently assessed by estimated glomerular filtration rate (GFR) using creatinine-based equations. The present paper investigates the relationship between GFR values determined using renal inulin clearance (Cin) and those estimated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formula. Our study was performed in 287 potential kidney donors with a mean age of 48 ± 10 years. Mean Cin was 1.47 ± 0.28 (1.10 - 2.50) mL/s/1.73 m2. Total bias when using the CKDEPI formula was -0.0183 mL/s/1.73 m2, precision 0.263 mL/s/1.73 m2, and accuracy 90.6% within ± 30% of Cin. The sensitivity of CKD-EPI to estimate a decrease in Cin below 1.33 mL/s/1.73 m2 was 50.5%, with an 85% specificity of detecting a value above the cutoff. Receiver-operating curve analysis for the above produced an area under the curve of 0.766 ± 0.0285 (CI 0.712 - 0.813). For donor screening purposes, CKD-EPI should be interpreted with great caution.
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Affiliation(s)
| | | | - Jan Maly
- Division of Professional Outpatient Care
| | - Janka Franekova
- Specialized Laboratory of Biochemistry, Department of Laboratory Methods
| | - Hana Malinska
- Department of Metabolism and Diabetes, Center for Experimental Medicine, and
| | | | | | - Jana Urbanova
- Department of Metabolism and Diabetes, Center for Experimental Medicine, and
| | - Jelena Skibova
- Department of Quality Control and Professional Programs, Division of Institute Management, Institute for Clinical and Experimental Medicine, Prague, Czech Republic
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Orešković D, Klarica M. Measurement of cerebrospinal fluid formation and absorption by ventriculo-cisternal perfusion: what is really measured? Croat Med J 2014; 55:317-27. [PMID: 25165046 PMCID: PMC4157383 DOI: 10.3325/cmj.2014.55.317] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [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: 06/26/2014] [Accepted: 07/22/2014] [Indexed: 11/05/2022] Open
Abstract
The generally accepted hypothesis on cerebrospinal fluid (CSF) hydrodynamics suggests that CSF is actively formed mainly by the choroid plexuses, circulates unidirectionally along the brain ventricles and subarachnoid space, and is passively absorbed mainly into the dural venous sinuses. CSF formation rate (Vf) has been extensively studied using the ventriculo-cisternal perfusion technique and the results have been used as the key evidence confirming the mentioned hypothesis. This technique and the equation for Vf calculation are based on the assumption that the dilution of the indicator substance is a consequence of the newly formed CSF, ie, that a higher CSF formation rate will result in a higher degree of dilution. However, it has been experimentally shown that the indicator substance dilution inside the CSF system does not occur because of a "newly formed" CSF, but as consequence of a number of other factors (departure of substances into the surrounding tissue, flowing around the collecting cannula into the cortical and spinal subarachnoid space, departure into the contralateral ventricle, etc). This technique allows "calculation" of the CSF formation even in dead animals, in an in vitro model, and in any other part of the CSF system outside the ventricles that is being perfused. Therefore, this method is indirect and any dilution of the indicator substance in the perfusate caused by other reasons would result in questionable and often contradictory conclusions regarding CSF formation rates.
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Affiliation(s)
- Darko Orešković
- Ruđer Bošković Institute, Department of Molecular Biology, Zagreb, Croatia
| | - Marijan Klarica
- Department of Pharmacology and Croatian Institute for Brain Research, University of Zagreb School of Medicine, Zagreb, Croatia
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Kamei K, Ito S, Iijima K. [Constant-infusion technique of inulin clearance without urine collection]. Nihon Jinzo Gakkai Shi 2011; 53:181-188. [PMID: 21516704] [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: 05/30/2023]
Abstract
Inulin clearance is accepted as the gold standard for estimating the glomerular filtration rate (GFR). However, the method of this examination is troublesome and infants need difficult bladder catheterization. The existence of residual urine results in an inaccurate estimation of GFR and the proceduse requires a large amount of transfusion. In the plasma infusion method, inulin reaches an equilibrium in which the inulin urinary excretion rate is equal to the infusion rate, and urine collection is unnecessary. We estimated GFR in 21 children using both the plasma infusion method and renal infusion method. In the renal infusion method, the loading infusion of 1% inulin was administered over 30 minutes at the dose of 5 mL/kg body weight, followed by maintenance infusion at the constant speed (mL/hour) of 1.5 x estimated GFR (mL/min/1.73 m2) x body surface area (m2)/ 1.73. Three 30-minute urine collections were performed and the plasma inulin levels were measured to estimate GFR. In the plasma infusion method, maintenance infusion was conducted at the speed (mL/hour) of 0.6 x estimated GFR (mL/min/1.73 m2) x body surface area (m2)/1.73. The mean plasma inulin concentrations at 8, 9 and 10 hours were examined and GFR was calculated with the infusion rate. The GFRs for the renal infusion methods (Cin) and plasma infusion methods (e-Cin) were 91.90 +/- 39.61 and 95.33 +/- 38.08 mL/min/1.73 m2, respectively. The values for Cin and e-Cin showed good linear correlation (R2 = 0.81). The value of e-Cin/Cin was 1.069 +/- 0.172 and the mean e-Cin value was only 7% higher than that of Cin. We believe that GFR estimated by the constant infusion method shows a value approximating that estimated by the standard method. This technique is noninvasive for infants and the GFR of children who have vesicoureteral reflux or residual urine in the bladder can be estimated. The method does not need a large amount of transfusion and is suitable for children with heart failure. We believe that this method is clinically useful.
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Affiliation(s)
- Koichi Kamei
- Department of Nephrology, National Center for Child Health and Development, Tokyo, Japan
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Wesolowski CA, Puetter RC, Ling L, Babyn PS. Tikhonov adaptively regularized gamma variate fitting to assess plasma clearance of inert renal markers. J Pharmacokinet Pharmacodyn 2010; 37:435-74. [PMID: 20865304 PMCID: PMC2953622 DOI: 10.1007/s10928-010-9167-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [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: 02/11/2010] [Accepted: 09/02/2010] [Indexed: 11/26/2022]
Abstract
The Tk-GV model fits Gamma Variates (GV) to data by Tikhonov regularization (Tk) with shrinkage constant, λ, chosen to minimize the relative error in plasma clearance, CL (ml/min). Using (169)Yb-DTPA and (99m)Tc-DTPA (n = 46, 8-9 samples, 5-240 min) bolus-dilution curves, results were obtained for fit methods: (1) Ordinary Least Squares (OLS) one and two exponential term (E₁ and E₂), (2) OLS-GV and (3) Tk-GV. Four tests examined the fit results for: (1) physicality of ranges of model parameters, (2) effects on parameter values when different data subsets are fit, (3) characterization of residuals, and (4) extrapolative error and agreement with published correction factors. Test 1 showed physical Tk-GV results, where OLS-GV fits sometimes-produced nonphysical CL. Test 2 showed the Tk-GV model produced good results with 4 or more samples drawn between 10 and 240 min. Test 3 showed that E₁ and E₂ failed goodness-of-fit testing whereas GV fits for t > 20 min were acceptably good. Test 4 showed CL(Tk-GV) clearance values agreed with published CL corrections with the general result that CL(E1) > CL(E2) > CL(Tk-GV) and finally that CL(Tk-GV) were considerably more robust, precise and accurate than CL(E2), and should replace the use of CL(E2) for these renal markers.
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Affiliation(s)
- Carl A Wesolowski
- Nuclear Medicine, The General Hospital, HSC, 300 Prince Philip Drive, St. John's, NF A1B 3V6, Canada.
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14
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Keller F, Hartmann B. An easy to calculate equation to estimate GFR based on inulin clearance. Nephrol Dial Transplant 2010; 25:1345-6; author reply 1346-7. [PMID: 20075434 DOI: 10.1093/ndt/gfp714] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
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Castenfors J, Piscator M. Renal haemodynamics, urine flow and urinary protein excretion during exercise in supine position at different loads. Acta Med Scand Suppl 2009; 472:231-44. [PMID: 5231565 DOI: 10.1111/j.0954-6820.1967.tb12630.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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Horio M, Imai E, Yasuda Y, Hishida A, Matsuo S. Simple sampling strategy for measuring inulin renal clearance. Clin Exp Nephrol 2008; 13:50-4. [PMID: 18827963 DOI: 10.1007/s10157-008-0084-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2008] [Accepted: 09/02/2008] [Indexed: 12/11/2022]
Abstract
BACKGROUND In the standard method of inulin clearance (Cin), three sets of serum and urine samples are collected during a 2-hour clearance period. For a practical use of this method, sampling should be the minimal number allowable while still providing enough accuracy. The aim of this study was to evaluate the validity of inulin renal clearance with assumed single urine collection with a period such as 30, 60 or 90 minutes. METHODS Inulin clearance data collected by the standard method from 737 individuals were used. Changes of serum inulin concentrations between 45 and 105 minutes after the start of the infusion were analyzed. We used first urine collection to calculate the inulin clearance with single urine collection (Cin-30 min). We assumed single urine collection for 60 or 90 minutes by combining the urine data of the consecutive 30-minute periods. Inulin clearances (Cin-60 min, Cin-90 min) were calculated from the assumed single urine collections, respectively. RESULTS Serum inulin concentration did not reach equilibrium during the clearance period. It increased in subjects with low glomerular filtration rate (GFR) and decreased in subjects with normal GFR. The amount of the change was small and -0.5 +/- 12.6% in subjects with GFR over 30 ml/min per 1.73 m(2). Cin-30 min, Cin-60 min and Cin-90 min showed high correlation coefficients against Cin-ST (0.962, 0.988 and 0.998, respectively). Systemic biases in these clearances were negligible (under 1 ml/min per 1.73 m(2)). Root mean square error (RMSE) were 10.4, 5.3 and 2.3 ml/min per 1.73 m(2) for Cin-30 min, Cin-60 min and Cin-90 min, respectively. These data indicated that accuracy of inulin clearance depends on the duration of the urine collection period. CONCLUSION Inulin clearance with a single urine collection is a convenient method. We showed that single urine collection for 30 minutes or a longer period has reasonable accuracy in calculation of inulin clearance. We propose a method of inulin clearance with single urine collection for 60 minutes.
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Affiliation(s)
- Masaru Horio
- Department of Functional Diagnostic Science, Course of Health Science, Osaka University Graduate School of Medicine, Suita, Osaka, Japan.
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Abstract
Previous investigations into the functional responses of the surviving nephrons following reductions in renal mass have been performed largely in anaesthetized animals and have taken little account of how the compensatory changes develop with time. The present study has assessed a method for determining glomerular filtration rate (GFR) in unrestrained, uncatheterized, conscious rats (plasma disappearance of (99m)Tc-diethylenetriamene pentaacetic acid (DTPA)) and has used this method to document the time course of the changes in GFR over a 32 day period following uninephrectomy or 5/6 nephrectomy. Concurrent measurements of excretion rates and of the clearance of lithium (the latter being an index of end-proximal fluid delivery) provided information on changes in overall tubular function and segmental reabsorption. After uninephrectomy, the GFR of the remaining kidney (compared with that of a single kidney of sham-operated animals) increased maximally (by approximately 50%) within 8 days; after 5/6 nephrectomy, the increase in the GFR of the remnant kidney was maximal (at approximately 300%) within 16 days. Overall excretion rates of sodium and potassium were well maintained in partially nephrectomized animals throughout the period of study, while the excretion of water increased (by approximately 30% after uninephrectomy and by approximately 120% after 5/6 nephrectomy), partly as a result of the compensatory increases in GFR but mainly as a consequence of moderate (after uninephrectomy) or marked (after 5/6 nephrectomy) reductions in fractional reabsorption. During the early period after 5/6 nephrectomy, potassium excretion sometimes exceeded the filtered load, indicating net secretion. Lithium clearance data indicated that the changes in tubular function after 5/6 nephrectomy include a reduction in fractional reabsorption in the proximal tubule, whereas after uninephrectomy any such effect on the proximal tubule is minor and transient.
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Affiliation(s)
- R M Chamberlain
- Department of Physiology and Centre for Nephrology, Royal Free & University College School of Medicine, Hampstead Campus, Rowland Hill Street, London NW3 2PF, UK
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Connors BA, Evan AP, Blomgren PM, Willis LR, Handa RK, Lifshitz DA, Lingeman JE, Ying J. Reducing shock number dramatically decreases lesion size in a juvenile kidney model. J Endourol 2007; 20:607-11. [PMID: 16999608 DOI: 10.1089/end.2006.20.607] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [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: 11/12/2022] Open
Abstract
BACKGROUND AND PURPOSE Adult stone patients are treated with several thousand lithotripter shockwaves (SWs) in order to pulverize a kidney stone. This typical clinical dose assures that the stone will be fractured completely. However, this same dose induces damage to the kidney, especially pediatric-size kidneys. If increasing SW number is known to increase renal injury and functional impairment, will reducing SW number below typical treatment levels significantly decrease kidney damage and hemodynamic changes? MATERIALS AND METHODS To address this question, one kidney in each of nine juvenile pigs (6-7 weeks old) was treated with 1000 SWs at 24 kV directed at a lower-pole calix with an unmodified HM-3 lithotripter. Parenchymal-lesion size was determined by sectioning the entire kidney and quantitating the amount of hemorrhage in each slice. Renal function was determined before and after SW treatment by inulin clearance, paraaminohippurate (PAH) extraction, and PAH clearance. The resulting morphologic and functional changes were then compared with those of kidneys that had been treated with a typical clinical dose of 2000 SWs (data previously published; J Am Soc Nephrol 2000;11:310). Eleven pigs were utilized as sham-treated controls. RESULTS Limiting SW number to 1000 significantly reduced the size of the lesion (by 95%) and reduced the degree of functional change (glomerular filtration rate by 38%, PAH extraction by 73%, renal plasma flow by 46%) compared with kidneys receiving 2000 SWs (an adult dose). CONCLUSIONS These data support the idea that SW number should be reduced to the lowest number that fractures kidney stones in order to minimize renal injury and functional impairment.
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Affiliation(s)
- Bret A Connors
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA.
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Lema G, Vogel A, Canessa R, Jalil R, Carvajal C, Becker P, Jaque MP, Fajardo C, Urzua J. Renal function and cardiopulmonary bypass in pediatric cardiac surgical patients. Pediatr Nephrol 2006; 21:1446-51. [PMID: 16902783 DOI: 10.1007/s00467-006-0221-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2006] [Revised: 04/05/2006] [Accepted: 05/08/2006] [Indexed: 11/25/2022]
Abstract
We studied prospectively the perioperative changes of renal function in nine children undergoing cardiac surgery with cardiopulmonary bypass (CPB). Glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) were measured with inulin and (131)I-hippuran clearances before CPB, during hypo and normothermic CPB, following sternal closure and 1 h postoperatively. Urinary alpha glutathione S-transferase (alpha GS-T) was measured pre- and postoperatively as a marker for tubular cellular damage. Plasma and urine creatinine and electrolytes were measured. Free water, osmolal and creatinine clearances, as well as fractional excretion of sodium (FeNa) and potassium transtubular gradient (TTKG) were calculated. GFR was normal before and after surgery. ERPF was low before and after surgery; it increased significantly immediately after CPB. Filtration fraction (FF) was abnormally elevated before and after surgery; however, a significant decrease during normothermic CPB and sternal closure was found. Alpha GS-T presented a moderate, but nonsignificant increase postoperatively. FeNa also increased in this period, but not significantly. Creatinine, osmolal, free water clearances, as well as TTKG, were normal in all patients pre- and postoperatively. We conclude that there is no evidence of clinically significant deterioration of renal function in children undergoing repair of cardiac lesions under CPB. Minor increases of alpha GS-T in urine postoperatively did not confirm cellular tubular damage. There was no tubular dysfunction at that time.
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Affiliation(s)
- Guillermo Lema
- Department of Anaesthesiology, Pontificia Universidad Católica de Chile, P.O. Box 114-D, Santiago, Chile.
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Perrin NESS, Torbjörnsdotter TB, Jaremko GA, Berg UB. The course of diabetic glomerulopathy in patients with type I diabetes: a 6-year follow-up with serial biopsies. Kidney Int 2006; 69:699-705. [PMID: 16518327 DOI: 10.1038/sj.ki.5000146] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Diabetic nephropathy is a severe complication and few studies have described the early morphological changes over time. Two kidney biopsies were performed, within a 6-year interval, in 29 primarily normoalbuminuric patients, aged 24 years at the second biopsy. These were examined with light and electron microscopy. Glomerular filtration rate, and effective renal plasma flow were determined with inulin and para-aminohippurate clearances. Urinary albumin excretion rate and the 24 ambulatory blood pressure were determined. Ten patients had developed microalbuminuria and/or hypertension; of these, six were treated with antihypertensive medication for 2 years or more. Significant increases were found in night time diastolic blood pressure and decreases in systolic and diastolic dipping. The glomerular volume, mesangial volume, mesangial matrix volume fraction and foot process width increased significantly. The group that was treated later for complications had the worst long-term metabolic control, thicker basement membranes and larger mesangial matrix and volume at the first biopsy, than the persistent normoalbuminuric group. During the follow-up, the untreated group with complications and the persistent normoalbuminuric group showed an increase in morphological parameters, whereas no progression occurred in the treated patients who also improved their metabolic control. In conclusion, the morphological parameters deteriorated in the normoalbuminuric patients and in those with complications, but were unchanged in the small antihypertensive-treated group with improved metabolic control.
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Affiliation(s)
- N E S S Perrin
- Department of Paediatrics, Karolinska Institutet, Karolinska University Hospital, Huddinge, Sweden.
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Girchev R, Markova P, Vuchidolova V. Influence of renal denervation on renal effects of acute nitric oxide and ETA/ETB receptor inhibition in conscious normotensive rats. J Physiol Pharmacol 2006; 57:17-27. [PMID: 16601312] [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] [Received: 12/27/2004] [Accepted: 02/03/2006] [Indexed: 05/08/2023]
Abstract
The role of renal nerves in the effects of concomitant NO synthase and non-selective ET(A/)ET(B) receptor inhibition on renal function was investigated in conscious normotensive Wistar rats. NO synthase inhibition alone (10 mg/kg b. w. i.v. L-NAME) in sham-operated rats with intact renal nerves induced an increase in systolic, diastolic and mean arterial pressure, urine flow rate, sodium, chloride and calcium excretion (p<0.05). The effect of L-NAME was markedly reduced by bosentan (10 mg/kg b.w. i.v.) and the values of urine flow rate, sodium, chloride and calcium excretions returned to control level (p<0.05). L-NAME administration one week after a bilateral renal denervation increased blood pressure to a similar extent as in sham-operated rats but decreased urine flow rate (p<0.05) and did not change electrolyte excretion. ET(A/)ET(B) receptor inhibition with bosentan during NO synthase inhibition in the renal denervated rats did not produce changes in urine flow rate or electrolyte excretion. NO synthase inhibition as well as concurrent NO synthase and ET(A/)ET(B) receptor inhibition did not change clearance of inulin or paraaminohippuric acid in sham-operated or renal denervated rats. These results indicate that renal sympathetic nerves play an important modulatory role in NO and endothelin induced effects on renal excretory function.
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Affiliation(s)
- R Girchev
- Department of Physiology, Medical University, Bulgaria.
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Wells A, Anderson WG, Cains JE, Cooper MW, Hazon N. Effects of angiotensin II and C-type natriuretic peptide on the in situ perfused trunk preparation of the dogfish, Scyliorhinus canicula. Gen Comp Endocrinol 2006; 145:109-15. [PMID: 16185690 DOI: 10.1016/j.ygcen.2005.08.002] [Citation(s) in RCA: 13] [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] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2005] [Revised: 08/03/2005] [Accepted: 08/05/2005] [Indexed: 11/16/2022]
Abstract
The renal roles of physiologically relevant doses of angiotensin II (Ang II) and C-type natriuretic peptide (CNP) were investigated in the dogfish, Scyliorhinus canicula, using an in situ perfused trunk preparation. Perfusion with 10(-9) M Ang II resulted in a glomerular antidiuresis and decreases in perfusate flow rate, transport maxima for glucose and the proportion of filtering glomeruli. In addition, the renal clearances and excretion of urea, sodium, and chloride were significantly reduced, whereas the relative clearances of these parameters remained unchanged. In contrast, perfusion of 10(-9) M CNP caused a glomerular diuresis, an increase in transport maxima for glucose, but no significant change in the proportion of filtering glomeruli. In addition, the renal clearances of urea, sodium, and chloride were significantly increased but there was no effect on the relative clearances of urea, sodium, or chloride. Perfusion with 10(-10) M Ang II or CNP had no significant renal effects. Our results suggest that these hormones act at the level of the glomeruli rather than at a tubular level.
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Affiliation(s)
- Alan Wells
- School of Biology, Gatty Marine Laboratory, University of St Andrews, St Andrews, Fife KY16 8LB, Scotland, UK.
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Pöge U, Gerhardt T, Stoffel-Wagner B, Klehr HU, Sauerbruch T, Woitas RP. Calculation of glomerular filtration rate based on cystatin C in cirrhotic patients. Nephrol Dial Transplant 2005; 21:660-4. [PMID: 16326735 DOI: 10.1093/ndt/gfi305] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.6] [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: 12/12/2022] Open
Abstract
BACKGROUND Plasma creatinine and creatinine clearance are of limited value for the estimation of renal function in cirrhotics. In these patients, cystatin C (Cys C) has been proposed as an alternative marker of glomerular filtration rate (GFR) and Cys C-based equations for calculation of GFR have been developed in non-cirrhotic patient cohorts. METHODS We retrospectively analyzed correlation, bias, precision and accuracy of two Cys C-based formulae (Larsson and Hoek) for GFR estimation in comparison with two creatinine-based equations (Cockroft & Gault and MDRD). The Cys C was determined by an immunonephelometric method. The GFR was measured by means of inulin clearance in 44 consecutive patients with liver cirrhosis. RESULTS On average, inulin clearance was 28.3 (95% CI: 29.2-41.3 ml/min/1.73 m2). Creatinine as well as Cys C-based equations overestimated the true GFR by 105-154%. However, Cys C-based equations showed significantly lower bias and higher precision than the creatinine-based formulae. Correlation and accuracy tended to be better with the Hoek and Larsson equation than with the Cockroft & Gault or MDRD formulae. Hoek and Larsson equations showed a similar diagnostic performance in all statistical procedures. CONCLUSION Our data suggest a significant improvement of GFR estimation in liver cirrhotics by means of the Cys C-based Hoek and Larsson formulae. However, all estimates remain a crude approximation of true GFR and thus cannot replace gold standard methods.
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Affiliation(s)
- U Pöge
- Department of Internal Medicine I, University of Bonn, Sigmund-Freud-Strasse 25, D 53105 Bonn, Germany.
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Kuan Y, Hossain M, Surman J, El Nahas AM, Haylor J. GFR prediction using the MDRD and Cockcroft and Gault equations in patients with end-stage renal disease. Nephrol Dial Transplant 2005; 20:2394-401. [PMID: 16115853 DOI: 10.1093/ndt/gfi076] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.3] [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: 11/13/2022] Open
Abstract
BACKGROUND Although prediction equations are recommended to determine GFR and creatinine clearance (CrCl), neither the MDRD equations nor the Cockcroft and Gault formula have been validated for the low levels of GFR present in end-stage renal disease (ESRD). The accuracy of the MDRD equations and the Cockcroft and Gault formula in predicting GFR and CrCl, respectively, was examined in patients with ESRD and its relationship to the basal GFR and two markers of malnutrition, urinary creatinine and body fat determined. METHODS Inulin clearance (C(in)) was measured in 26 non-diabetic patients with ESRD and the 24 h CrCl determined. GFR was predicted using three equations derived from the MDRD study population containing four to six variables. Both CrCl and GFR were predicted from the Cockcroft and Gault formula. Estimates of bias and precision were obtained and Bland and Altman analysis performed. Body fat was measured by DEXA scan. RESULTS The predicted GFR (MDRD) was 10% lower than C(in) (8.83+/-0.71 ml/min/1.73 m2) with all three MDRD equations, showing a similar degree of precision and bias. C(in) gave a negative correlation with the difference between the predicted GFR (MDRD) and the measured GFR. The predicted GFR (MDRD) underestimated GFR when C(in) >8 ml/min/1.73 m2 but overestimated GFR when C(in) <8 ml/min/1.73 m2. The Cockcroft and Gault formula overestimated CrCl by 14% and overestimated C(in) by 35%. C(in) gave a negative correlation with the difference between the predicted GFR (Cockcroft and Gault) and measured GFR, overestimating GFR when C(in) <13 ml/min/1.73 m2. The overestimation of GFR by the MDRD equation was not associated with urinary creatinine excretion. However, both Cockcroft and Gault and the MDRD predictions showed a positive, but weak, correlation with body fat. CONCLUSION The MDRD equations were more accurate in predicting the group mean GFR in patients with ESRD than the Cockcroft and Gault formula. However, the predicted GFR using either formula was related to the basal GFR and percentage body fat.
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Affiliation(s)
- Ying Kuan
- Sheffield Kidney Institute, Northern General Hospital, Herries Road, Sheffield S5 7AU, UK
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Finco DR. Measurement of glomerular filtration rate via urinary clearance of inulin and plasma clearance of technetium Tc 99m pentetate and exogenous creatinine in dogs. Am J Vet Res 2005; 66:1046-55. [PMID: 16008230 DOI: 10.2460/ajvr.2005.66.1046] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [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: 11/20/2022]
Abstract
OBJECTIVE To compare glomerular filtration rate (GFR) measured via urinary clearance of inulin (UCI) with plasma clearance of technetium Tc 99m pentetate (99mTc-pentetate) and creatinine in dogs. ANIMALS 6 healthy Beagles and 18 Beagles with reduced renal function. PROCEDURE 13 blood samples were obtained between 5 and 600 minutes after i.v. bolus injections of (99m)Tc-pentetate and creatinine. Plasma clearance of (99m)Tc-pentetate was computed on the basis of 1, 2, or 13 samples, and plasma clearance of creatinine was computed on the basis of 2, 5, or 13 samples. During plasma clearance procedures, constant i.v. infusion of carboxyl carbon 14 inulin was begun and UCI was determined in urine collected from 90 to 120, 120 to 180, and 180 to 240 minutes. Clearance procedures were repeated in 12 dogs to evaluate reproducibility of results. RESULTS Significant association between UCI and plasma clearance was determined via all methods. However, plasma clearances were moderately to markedly different from UCI, depending on test substance, GFR, and sample numbers used for plasma clearance computations. Comparisons were particularly discordant when some methods of limiting samples were used to define plasma clearance. CONCLUSIONS AND CLINICAL RELEVANCE Values derived from plasma clearance methods for (99m)Tc-pentetate and creatinine were not interchangeable with UCI results, which raises questions about their reliability as clinical research tools for measurement of GFR. Plasma clearance methods that are relative indices of renal function should not be interpreted as accurate measures of GFR without validation.
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Affiliation(s)
- Delmar R Finco
- Department of Physiology and Pharmacology, College of Veterinary Medicine, The University of Georgia, Athens, GA 30602, USA
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Orita Y, Gejyo F, Sakatsume M, Shiigai T, Maeda Y, Imai E, Fujii T, Endoh M, Jinde K, Haneda M, Sugimoto T, Hishida A, Takahashi S, Hosoya T, Yamamoto H, Hora K, Okada Y, Hosaka S, Oguchi T, Kanno Y, Nishio Y, Yano S, Aikawa K, Yasui K. [Estimation of glomerular filtration rate by inulin clearance: comparison with creatinine clearance]. Nihon Jinzo Gakkai Shi 2005; 47:804-12. [PMID: 16296410] [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: 05/05/2023]
Abstract
Inulin clearance (Cin) is widely believed to be the gold standard of the glomerular filtration rate (GFR). However, in Japan, Cin has not been officially recognized by the Ministry of Health, Labour and Welfare of Japan for clinical use. Creatinine clearance (Ccr) has been used to estimate the renal function of patients, but there have been many studies in which Ccr estimates were GFR falsely high because the metabolism and tubular excretion of creatinine widely varied according to the pathophysiological state of the patient. In the present study, we determined Cin and Ccr simultaneously in 116 adult patients with renal diseases and diabetic mellitus. The clearance study was performed by the modified Wesson's method. The inulin preparation was FFI-1010 (Fuji Yakuhin Co. Ltd.). Inulin in serum and urine was determined by the newly devised enzymatic assay (Toyobo Co. Ltd.), which is specific for inulin. The mean Cin was 35.0 +/- 14.4 ml/min/1.73 m2. The mean Ccr(the enzyme assay) was 63.6 +/- 24.1 ml/min/1.73 m2 and that of the kinetic Jaffe assay was 55.3 +/- 19.3 ml/min/1.73 m2. Mean Ccr/Cin was 1.93 +/- 0.73, 1.69 +/- 0.62, respectively. This ratio was significantly different(p < 0.05) in the degree of reduction of Cin, with values of 2.07 +/- 0.82 (Cin < 40 ml/min/1.73 m2) and 1.64 +/- 0.32(40 < Cin < 80 ml/min/1.73 m2), respectively. Only 8 patients were classified into the same degree of reduced renal function (the Guideline of Japanese Society of Nephrology). The findings of this study suggest that the GFR determined by Ccr could misjudge the renal function of patient and delay the administration of proper treatment of the patient. Introduction of Cin into the clinical field is necessary to avoid this delay.
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Abstract
BACKGROUND Ischemic nephropathy is a common cause of end-stage renal disease. Exploration of the mechanisms of deterioration of renal function is limited due to lack of noninvasive techniques available to study the single kidney. The Blood Oxygen Level-Dependent (BOLD) MRI method can measure deoxyhemoglobin and therefore indirectly estimates renal oxygen content, but has never been evaluated in renal artery stenosis (RAS). This study was therefore designed to test if BOLD can detect the characteristic of renal hypoxia induced by RAS. METHODS RAS was induced in 8 pigs using an occluder placed around the right renal artery. Renal blood flow (RBF) was measured continuously with an ultrasound probe. BOLD signal was measured bilaterally in the cortex and medulla (as the slope of the logarithm of MR signal) at baseline and at the lower limit of RBF autoregulation. The measurements were then repeated during six sequential graded decreases in RBF (80 to 0% of baseline) and during recovery. RESULTS During the control period, BOLD signals were not significantly different between the right and the left kidneys. In the occluded kidney, BOLD signal of the cortex (19.3 +/- 1.9/s) and the medulla (17.3 +/- 2.0/s) increased during occlusion gradually and significantly (P < 0.0001) to a maximum (at total occlusion) of 33.8 +/- 2.0/s (+79%) and 29.8 +/- 2.3/s (+78%), respectively, and returned to baseline values during recovery. CONCLUSION This study shows that the BOLD technique can noninvasively detect change in intra-renal oxygenation during an acute reduction of RBF. This study provides a strong rationale for developing the BOLD method for the detection and evaluation of renal hypoxia induced by RAS, which may be potentially applicable in humans.
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Affiliation(s)
- Laurent Juillard
- Department of Physiology, Mayo Clinic, Rochester, Minnesota 55905, USA
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DeRubertis FR, Craven PA, Melhem MF, Salah EM. Attenuation of renal injury in db/db mice overexpressing superoxide dismutase: evidence for reduced superoxide-nitric oxide interaction. Diabetes 2004; 53:762-8. [PMID: 14988262 DOI: 10.2337/diabetes.53.3.762] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The effects of overexpression of Cu(2+)/Zn(2+) superoxide dismutase-1 (SOD-1) on indexes of renal injury were compared in 5-month-old nontransgenic (NTg) db/db mice and db/db mice hemizygous for the human SOD-1 transgene (SOD-Tg). Both diabetic groups exhibited similar hyperglycemia and weight gain. However, in NTg-db/db mice, albuminuria, glomerular accumulation of immunoreactive transforming growth factor-beta, collagen alpha1(IV), nitrotyrosine, and mesangial matrix were all significantly increased compared with either nondiabetic mice or SOD-Tg-db/db. SOD-1 activity and reduced glutathione levels were higher, whereas malondialdehyde content was lower, in the renal cortex of SOD-Tg-db/db compared with NTg-db/db mice, consistent with a renal antioxidant effect in the transgenic mice. Inulin clearance (C(IN)) and urinary excretion of guanosine 3',5'-cyclic monophosphate (U(cGMP)) were increased in SOD-Tg-db/db mice compared with corresponding values in nondiabetic mice or NTg-db/db mice. C(IN) and U(cGMP) were suppressed by Nomega-nitro-L-arginine methyl ester in SOD-Tg-db/db but not in NTg-db/db mice, implying nitric oxide (NO) dependence of these increases and enhanced renal NO bioactivity in SOD-Tg-db/db. Studies of NO-responsive cGMP in isolated glomeruli supported greater quenching of NO in glomeruli from NTg-db/db compared with SOD-Tg-db/db mice. Evidence of increased NO responsiveness and the suppression of glomerular nitrotyrosine may both reflect reduced NO-superoxide interaction in SOD-Tg-db/db mice. The results implicate superoxide in the pathogenesis of diabetic nephropathy.
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Affiliation(s)
- Frederick R DeRubertis
- Departments of Medicine and Pathology, Veterans Affairs Pittsburgh Healthcare System and University of Pittsburgh, School of Medicine, Pittsburgh, Pennsylvania, USA.
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Qi Z, Whitt I, Mehta A, Jin J, Zhao M, Harris RC, Fogo AB, Breyer MD. Serial determination of glomerular filtration rate in conscious mice using FITC-inulin clearance. Am J Physiol Renal Physiol 2003; 286:F590-6. [PMID: 14600035 DOI: 10.1152/ajprenal.00324.2003] [Citation(s) in RCA: 266] [Impact Index Per Article: 12.7] [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: 12/13/2022] Open
Abstract
Two nonradioactive methods for determining glomerular filtration rate (GFR) in conscious mice using FITC-labeled inulin (FITC-inulin) were evaluated. The first method measured GFR using clearance kinetics of plasma FITC-inulin after a single bolus injection. Based on a two-compartment model, estimated GFR was 236.69 +/- 16.55 and 140.20 +/- 22.27 microl/min in male and female C57BL/6J mice, respectively. Total or (5/6) nephrectomy reduced inulin clearance to 0 or 32.80 +/- 9.32 microl/min, respectively. Conversely, diabetes mellitus induced by streptozotocin was associated with increased GFR. The other approach measured urinary inulin clearance using intraperitoneal microosmotic pumps to deliver FITC-inulin and metabolic cages to collect timed urine samples. This approach yielded similar GFR values of 211.11 +/- 26.56 and 157.36 +/- 20.02 microl/min in male and female mice, respectively. These studies demonstrate the feasibility of repeated nonisotopic measurement of inulin clearance in conscious mice.
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Affiliation(s)
- Zhonghua Qi
- Department of Medicine, Vanderbilt University, Nashville, TN 37212, USA.
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Abstract
AIM Inulin clearance (Cin) is the gold standard for assessing glomerular filtration rate (GFR). Other methods are based on the plasma creatinine concentration (Pcreat), creatinine clearance (Ccreat), the Haycock-Schwartz formula and the plasma concentration of cystatin C (PcysC), a 13 kDa basic protein produced at a constant rate by all nucleated cells. The present prospective study was thus designed to evaluate the reliability of PcysC as a marker of GFR in comparison with that of Pcreat, Ccreat and the Haycock-Schwartz formula, using Cin as the gold standard. METHODS Ninety-nine children (51 m/48 f), with a median age of 8.3 y (1.0-17.9) were studied. Using a cut-off for Cin of 100 ml/min per 1.73 m2, 54 children (54.5%) had impaired GFR. Those with normal GFR were comparable for age, height, weight and body mass index. RESULTS Logistic regression, ROC analysis and linear regression all showed that Ccreat was the best parameter to discriminate between impaired and normal GFR, followed by the Haycock-Schwartz formula, PcysC, and finally Pcreat, each one being significantly more predictive than the next. CONCLUSION GFR is better assessed by the Haycock-Schwartz formula than by PcysC or Pcreat alone. It is therefore concluded that when urine collection is not possible, simply measuring the child's Pcreat and height is the best, easiest and cheapest way to assess GFR.
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Affiliation(s)
- S Martini
- Department of Paediatrics, Renal Unit, University Medical Centre, Lausanne, Switzerland
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Abstract
Filtered myo-inositol, an important renal intracellular organic osmolyte, is almost completely reabsorbed. To examine tubule sites and specificity and, thus possible mechanism of this reabsorption, we microinfused myo-[(3)H]inositol or D-[(3)H]glucose into early proximal (EP), late proximal (LP), or early distal tubule sections of superficial nephrons and into long loops of Henle (LLH) of juxtamedullary nephrons and papillary vasa recta in rats in vivo et situ and determined urinary fractional recovery of the (3)H label compared with comicroinfused [(14)C]inulin. To determine the extent to which the proximal convoluted tubule (PCT) alone contributes to myo-inositol reabsorption, we also microperfused this tubule segment between EP and LP puncture sites. We examined specificity of reabsorptive carrier(s) by adding high concentrations of other polyols and monosaccharides to the infusate. The results show that >60% of the physiological glomerular load of myo-inositol can be reabsorbed in the PCT and >90% in the short loop of Henle (SLH) by a saturable, phloridzin-sensitive process. myo-Inositol can also be reabsorbed in the ascending limb of LLH and can move from papillary vasa recta blood into ipsilateral tubular structures. Essentially no reabsorption occurred in nephron segments beyond the SLH or in collecting ducts. Specificity studies indicate that reabsorption probably occurs via a luminal Na(+)-myo-inositol cotransporter.
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Affiliation(s)
- Stefan Silbernagl
- Physiologisches Institut der Universität Würzburg, D-97070 Würzburg, Germany.
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Abstract
In this study, we investigated the ability of acute infusions of isoprenaline to alter renin and angiotensinogen gene expression in the kidney of rats anaesthetised with chloralose-urethane. Groups of rats received I.V. infusions of either saline or the beta-adrenoceptor agonist isoprenaline at 400 ng x kg(-1) x min(-1) for 4 h. The isoprenaline infusion caused a sustained decrease in mean blood pressure of approximately 20 mmHg (P < 0.01), an increase in heart rate of 50 beats x min(-1) (P < 0.01) and reductions in urine flow and sodium excretion of 80-90 % (both P < 0.01). Renal blood flow and glomerular filtration rate were transiently reduced by 21 % (P < 0.01) and 61 % (P < 0.001), respectively, in the first hour, recovering to baseline levels after 4 h of infusion. At the end of the study, plasma renin activity was raised approximately 6-fold (P < 0.01) while renal renin and angiotensinogen mRNA levels were 1.8- and 1.5-fold higher (both P < 0.05) compared to the control group (saline infusion). The isoprenaline-induced renin secretion could have been mediated via the activation of beta-adrenoceptors resulting in the exocytosis of renin-containing granules, with a smaller contribution being due to reduced renal haemodynamics. The increase in renal renin gene expression in response to isoprenaline was probably due primarily to the intracellular signalling processes acting directly on nuclear mechanisms. Similarly, the increased renal angiotensinogen gene expression most probably reflected a direct action of the isoprenaline. These findings provide evidence that catecholamines are involved in mechanisms that rapidly alter the expression of the genes of the renin-angiotensin system within the kidney.
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Affiliation(s)
- S Mostafa Shid Moosavi
- Department of Physiology, The Medical School, Shiraz University of Medical Sciences, Shiraz 71348, Iran.
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35
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Pundziene B. [The value and adaptability of glomerular filtration rate and reserve test (review of the literature)]. Medicina (Kaunas) 2002; 38:6-15. [PMID: 12474711] [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: 02/28/2023]
Abstract
In normal conditions only 75% of kidney function capability are in use. Resting part of kidney function is called renal functional reserve. It is a very important indicator for prediction of renal insufficiency in chronic renal diseases, morphological changes or reduced mass of kidney parenchyma. More common test to estimate renal functional reserve is a method of measurement of glomerular filtration rate (clearance) before and after provocation of renal filtration by acute peroral protein load. The value and the possibilities to put in practice this test as well the factors influencing the results of glomerular filtration rate were estimated in this review.
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Affiliation(s)
- Birute Pundziene
- Kauno medicinos universiteto kliniku Vaiku ligu klinika, Eiveniu 2, Kaunas 3007.
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Goldfarb-Rumyantzev AS, Cheung AK, Leypoldt JK. Computer simulation of small-solute and middle-molecule removal during short daily and long thrice-weekly hemodialysis. Am J Kidney Dis 2002; 40:1211-8. [PMID: 12460040 DOI: 10.1053/ajkd.2002.36883] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [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: 11/11/2022]
Abstract
BACKGROUND More intensive hemodialysis (HD) regimens (short daily and long thrice-weekly HD) provide potential opportunities for improved patient outcome. An adequate dialysis dose for these regimens cannot be established from the existing literature. METHODS Using computer simulation, we compared conventional HD with short daily HD and long thrice-weekly HD using two dose measures of solute clearance: equivalent renal clearance (EKR) and a generalized standard Kt/V (stdKt/V) for urea, creatinine, vitamin B12, inulin, and beta2-microglobulin. Solute kinetics were simulated using a variable-volume two-compartment mathematical model. RESULTS Calculated EKR values were greater during short daily HD compared with those during conventional HD by 16.9%, 15.5%, 16.1%, 5.2%, and 2.5% for urea, creatinine, vitamin B12, inulin, and beta(2)-microglobulin, respectively. Calculated stdKt/V values predicted more substantial increases in dose for all solutes. Increasing the time of dialysis from 4 to 8 hours three times weekly resulted in substantially greater stdKt/V and EKR values compared with both conventional and short daily HD. Solute clearances during short daily HD could be enhanced to approach those during long HD if treatment time was increased or very high surface area dialyzers were used with very high blood flow rates. CONCLUSION Dose measures for all molecules larger than urea increase with either increased frequency or, even more so, increased duration of dialysis. Prediction results of these models require confirmation in clinical studies. Furthermore, the relationship between increased dialysis dose and long-term clinical outcome during more intensive HD regimens requires examination in clinical trials.
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Affiliation(s)
- Alexander S Goldfarb-Rumyantzev
- Division of Nephrology and Hypertension, University of Utah, School of Medicine, and VA Salt Lake City Health Care System, Salt Lake City, UT 84112, USA.
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Schaeffer RC, Gratrix ML, Mucha DR, Carbajal JM. The rat glomerular filtration barrier does not show negative charge selectivity. Microcirculation 2002; 9:329-42. [PMID: 12375171 DOI: 10.1038/sj.mn.7800150] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [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] [Received: 06/25/1999] [Accepted: 05/08/2001] [Indexed: 11/09/2022]
Abstract
OBJECTIVE To characterize the effects of size, shape, and negative charge on the transport of macromolecules across the glomerular capillary wall by using the sieving curves (fractional clearance vs. solute molecular radii) of fluorescent polydispersed polysaccharide tracers. METHODS Glomerular fractional clearances (FC) were measured with fluorescent neutral [isoelectric point (pI) = 7.3 +/- 0.2] and negatively charged (pI = 3.5 +/- 0.4) dextrans (DEX) in comparison with negatively charged (pI = 4.8 +/- 0.3) hydroxy ethyl starch (HES) and (pI = 4.6 +/- 0.1) bovine serum albumin (BSA) in Sprague-Dawley and Fischer 344/Brown Norway rats. FCs (n = 53) were measured by using the urinary clearance of (14)C-inulin to determine the glomerular filtration rate. The relative uptake of each fluorescent probe by endothelial and renal proximal tubule epithelial (LLC-PK(1)) cells, in vitro, was measured microscopically by using a cooled (-25 degrees C) CCD camera. RESULTS The sieving curves for randomly coiled neutral and negatively charged DEX probes were identical. These FC values were 6-fold greater than those for HES and 200-fold above similarly sized fluorescent BSA. The polysaccharide probes did not show significant binding to serum proteins. The uptake of BSA by LLC-PK(1) cells was 20- to 100-fold greater than that for neutral or negatively charged macromolecules. CONCLUSIONS These findings indicate that the rat glomerular filtration barrier restricts the transport of polysaccharide macromolecules as a function of their size and configuration but not negative charge.
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Watson ADJ, Lefebvre HP, Concordet D, Laroute V, Ferré JP, Braun JP, Conchou F, Toutain PL. Plasma exogenous creatinine clearance test in dogs: comparison with other methods and proposed limited sampling strategy. J Vet Intern Med 2002; 16:22-33. [PMID: 11826881 DOI: 10.1892/0891-6640(2002)016<0022:peccti>2.3.co;2] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Plasma clearance of creatinine was evaluated for assessment of glomerular filtration rate (GFR) in dogs. In 6 healthy dogs (Experiment 1), we determined 24-hour urine clearance of endogenous creatinine, plasma, and urine clearances of exogenous creatinine administered at 40, 80, and 160 mg/kg in a crossover design (linearity study), plasma iothalamate clearance, and plasma and urine clearances of 14C-inulin. In Experiment 2, plasma creatinine and iothalamate clearances were compared, and a linearity study was performed as for Experiment 1 in 6 dogs with surgically induced renal impairment. Experiment 3 compared plasma creatinine clearance with plasma iothalamate clearance before and 3 weeks after induction of moderate renal impairment in 6 dogs. Plasma creatinine clearances were calculated by both noncompartmental and compartmental analyses. In Experiment 1, plasma inulin clearance was higher (P < .001) than other clearance values. Plasma creatinine clearances at the 3 dose rates did not differ from urine inulin clearance and each other. In Experiment 2, plasma creatinine clearances were about 14% lower than plasma iothalamate clearance (P < .05). In Experiment 3, decreases in GFR assessed by plasma clearances of iothalamate and creatinine were similar. Renal failure decreased the daily endogenous input rate of creatinine by 25%. Limiting sampling strategies for optimizing GFR calculation were proposed, allowing an error lower than 6.5% with 4 blood samples. These results suggest that determination of plasma creatinine clearance by a noncompartmental approach offers a reliable, inexpensive, rapid, and convenient means of estimating GFR in routine practice.
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Affiliation(s)
- A D J Watson
- Veterinary Medicine, The University of Sydney, NSW, Australia.
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Teruel MJ, Carbonell LF, Teruel MG, Parrilla JJ, Abad L, Hernandez I. Effect of angiotensin-converting enzyme inhibitor on renal function in ovarian hyperstimulation syndrome in the rabbit. Fertil Steril 2001; 76:1232-7. [PMID: 11730756 DOI: 10.1016/s0015-0282(01)02869-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [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: 11/23/2022]
Abstract
OBJECTIVE To investigate renal function and whether captopril prevents alterations in the handling of sodium and water in the ovarian hyperstimulation syndrome (OHSS) in the rabbit. DESIGN Experimental study SETTING Physiology laboratory. ANIMAL(S) Six female New Zealand white rabbits were used as controls, and 13 were hyperstimulated with gonadotropins. INTERVENTION(S) Saline or captopril. MAIN OUTCOME MEASURE(S) Renal excretory and hemodynamic variables. RESULT(S) The 3% extracellular volume expansion in OHSS animals induced a significant elevation in mean arterial pressure by 27%, although increments in natriuresis and diuresis were similar to those observed in controls. The OHSS group had impaired pressure-natriuresis sensitivity compared with controls (0.36 +/- 0.07 microEq/min/g of Na excreted per mm Hg vs. 1.74 +/- 0.45 microEq/min/g of Na excreted per mm Hg; P<.05. Captopril significantly reduced mean arterial pressure (P<.05) and shifted the pressure-natriuresis response to the left by 0.85 +/- 0.17 microEq/min/g of Na excreted per mm Hg (P<.05). CONCLUSION(S) In OHSS in the rabbit model, pressure-natriuresis sensitivity is impaired. Angiotensin II may play a significant role in this phenomenon, since angiotensin-converting enzyme inhibition normalized the pressure-natriuresis relationship.
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Affiliation(s)
- M J Teruel
- Departmento de Fisiología de la Universidad de Murcia, Murcia, Spain
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Abstract
BACKGROUND Renal dysfunction occurs in children with liver diseases and renal function is often further impaired after orthotopic liver transplantation (OLT). Inaccurate methods of determining renal function are used in many cases. We studied renal function with accurate methods before and repeatedly after OLT to analyze the effect of the underlying diseases, hypertension, and the immunosuppressive agents. METHODS A total of 46 children were studied both before and annually after OLT with clearances of inulin and paraaminohippuric acid to determine the glomerular filtration rate (GFR) and effective renal plasma flow (ERPF). The clearance of inulin was also compared with the formula creatinine clearance. RESULTS GFR and ERPF decreased from before to after OLT and decreased further during the first years after OLT. Patients with extrahepatic biliary atresia and with tumours showed higher GFR 1 year after OLT than those with metabolic and miscellaneous disorders. No significant change in GFR of individual patients occurred from the first to the last values determined at around 1 and 6 years after OLT. No difference in renal function was seen during the first years between patients treated with cyclosporine as compared to those treated with tacrolimus, but 4 years after OLT, the GFR was higher in the tacrolimus-treated patients. Patients on antihypertensive agents had lower GFR than the normotensive ones. There was no agreement between GFR, determined by clearance of inulin, and that calculated on the basis of serum creatinine and the height of the patients. CONCLUSIONS Renal function is reduced by OLT and decreases further during the first years after OLT. Patients with metabolic disorders and those on antihypertensive treatment have the lowest GFR. Determination of GFR by the formula creatinine clearance is inaccurate in children after liver transplantation.
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Affiliation(s)
- U B Berg
- Department of Paediatrics, Karolinska Institutet, Huddinge University Hospital, Stockholm, Sweden
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Marsilio R, Naturale M, Manghi P, Montini G, Murer L, Ros M, Bisogno G, Andretta B, Dussini N, Giordano G, Zacchello G, Dall'Amico R. Rapid and simple determination of inulin in biological fluids by high-performance liquid chromatography with light-scattering detection. J Chromatogr B Biomed Sci Appl 2000; 744:241-7. [PMID: 10993511 DOI: 10.1016/s0378-4347(00)00226-7] [Citation(s) in RCA: 15] [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] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We report a new high-performance liquid chromatography method developed for measuring inulin in plasma and urine using ion moderated partition chromatography and evaporative light-scattering detection. Samples are deproteinized with a zinc acetate and phosphotungstic acid solution and added with melezitose as an internal standard. The chromatographic separation is carried out in 16 min at a flow-rate of 0.6 ml/min using deionized water as the mobile phase. Within-run precision, measured at four different concentrations (0.050 mg/ml, 0.150 mg/ml, 0.300 mg/ml and 1.200 mg/ml), ranges from 1.7 to 3.4% in plasma and from 1.5 to 3.5% in urine. Similarly, between-run precision is in plasma from 2.0 to 4.3% and in urine from 2.0 to 4.4%. Analytical recovery ranges from 97.9 to 100.1% in plasma and from 99.1 to 99.7% in urine, respectively. Detection limit (signal-to-noise ratio=3) is 5 microg/ml both in plasma and urine. The method is simple, sensitive, without interference due to hexoses or drugs commonly taken by patients with renal diseases, and offers the advantage of measuring inulin without previous hydrolysis of the molecule.
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Affiliation(s)
- R Marsilio
- Department of Pediatrics, University of Padua, Italy
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42
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Abstract
Recent data indicate that bradykinin participates in the regulation of neonatal glomerular function and also acts as a growth regulator during renal development. The aim of the present study was to investigate the involvement of bradykinin in the maturation of renal function. Bradykinin beta2-receptors of newborn rabbits were inhibited for 4 days by Hoe 140. The animals were treated with 300 microg/kg s.c. Hoe 140 (group Hoe, n = 8) or 0.9% NaCl (group control, n = 8) twice daily. Clearance studies were performed in anesthetized rabbits at the age of 8-9 days. Bradykinin receptor blockade did not impair kidney growth, as demonstrated by similar kidney weights in the two groups, nor did it influence blood pressure. Renal blood flow was higher, while renal vascular resistance and filtration fraction were lower in Hoe 140-treated rabbits. No difference in glomerular filtration rate was observed. The unexpectedly higher renal perfusion observed in group Hoe cannot be explained by the blockade of the known vasodilator and trophic effect of bradykinin. Our results indicate that in intact kallikrein-kinin system is necessary for the normal functional development of the kidney.
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Affiliation(s)
- P Tóth-Heyn
- Service de Pédiatrie, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
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43
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Abstract
It is still debatable whether acute poststreptococcal glomerulonephritis (APSGN) can lead to permanent renal impairment. The clinical, immunological, and histological findings during the acute disease have been described thoroughly, however, the hemodynamic events are still poorly understood. In this retrospective study, the inulin and p-aminohippurate clearances were measured to evaluate glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) within a month of onset of the disease (acute stage) in 26 children, and 2-12 months after onset (follow-up) in 22 children with APSGN. During the acute stage, the mean GFR was 77+/-23 (SD) ml/min per 1.73 m(2), the mean ERPF 537+/-138 ml/min per 1.73 m(2), and the filtration fraction (FF) 14%+/-3%, compared with values for controls of 115+/-11 ml/min per 1. 73 m(2), 607+/-72 ml/min per 1.73 m(2), and 19%+/-2%, respectively (n=42). At follow-up, GFR was 114+/-15 ml/min per 1.73 m(2), ERPF 600+/-68 ml/min per 1.73 m(2), and FF 19%+/-3%. Thus, during the disease both GFR and ERPF fell below values for controls, but later were restored. The GFR, however, was more reduced than the ERPF, as indicated by the reduced FF. This might reflect a relative hyperperfusion of individual nephrons, which might start processes later deleterious to the nephrons. This finding, however, needs to be further investigated and we have therefore started a long-term follow-up of these patients.
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Affiliation(s)
- M Herthelius
- Department of Pediatrics, Karolinska Institutet, Huddinge University Hospital, S-141 86 Huddinge, Sweden
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44
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Baccard N, Hoizey G, Frances C, Lamiable D, Trenque T, Millart H. Simultaneous determination of inulin and p-aminohippuric acid (PAH) in human plasma and urine by high-performance liquid chromatography. Analyst 1999; 124:833-6. [PMID: 10736868 DOI: 10.1039/a902009h] [Citation(s) in RCA: 9] [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: 11/21/2022]
Abstract
Inulin and p-aminohippuric acid (PAH) clearances are used for the estimation of glomerular filtration rate (GFR) and effective renal plasma flow (ERPF). A simple and rapid high-performance liquid chromatography (HPLC) method with UV detection is described for the simultaneous determination of inulin and PAH in the same chromatogram in the plasma and urine of humans. Plasma and urine samples were hydrolyzed with perchloric acid (0.7%) in boiling water. The mobile phase consisted of 0.01 M potassium dihydrogenphosphate with 0.02 M tetramethylammonium chloride and o-phosphoric acid (pH 3)-acetonitrile (94:6, v/v), pumped at a rate of 1.2 ml min-1 on a C8 reversed-phase column. Tannic acid was used as the internal standard and UV detection at 285 nm was employed. The calibration curves were linear over the concentration range of 12.5-100 mg l-1 for inulin and 6.25-50 mg l-1 for PAH with determination coefficients greater than 0.997. The method is accurate (bias < 13%) and reproducible (intra- and inter-day relative standard deviation less than 11%), with a limit of quantitation of 12.5 mg l-1 and 6.25 mg l-1 for inulin and PAH, respectively. Analytical recoveries from urine and plasma were ranged from 81 to 108% for both compounds. This fully validated method, which allows the simultaneous determination of inulin and PAH clearances, is simple, rapid (total run time < 10 min) and requires only a 200 microliters plasma or urine sample.
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Affiliation(s)
- N Baccard
- Laboratoire de Pharmacologie-Toxicologie, Hôpital Maison Blanche, C.H.U. de Reims, France
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45
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Fredman B, Zohar E, Golan E, Tillinger M, Bernheim J, Jedeikin R. Diclofenac does not decrease renal blood flow or glomerular filtration in elderly patients undergoing orthopedic surgery. Anesth Analg 1999; 88:149-54. [PMID: 9895083 DOI: 10.1097/00000539-199901000-00028] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [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: 10/26/2022]
Abstract
UNLABELLED Nonsteroidal antiinflammatory drugs (NSAIDs) have become increasingly popular in the treatment of perioperative pain. Due to concerns that cyclooxygenase inhibition may adversely affect renal function, these drugs are often not used in geriatric surgical patients. However, the perioperative effect of NSAIDs on renal blood flow (RBF) and glomerular filtration rate (GFR) has not been assessed. Therefore, using a prospective, controlled, double-blinded study design, we evaluated the effect of diclofenac on RBF and GFR in 20 patients (>65 yr) undergoing open reduction and internal fixation of the femur. All patients were normovolemic before the study. A standardized general anesthetic was administered. On induction of anesthesia, patients in the diclofenac group received an IV bolus of diclofenac (0.7 mg/kg) followed by a constant infusion (0.15 mg x kg(-1) x h(-1)) until the end of surgery. In the saline group, an equal volume of saline was administered. During four time periods (equilibration, anesthesia, surgical, recovery), GFR and effective renal plasma flow (ERPF) were measured by inulin and paraaminohippurate clearance, respectively. After the induction of anesthesia and throughout the surgical period, ERPF and GFR were significantly decreased compared with preoperative baseline values. However, no difference was demonstrated between the groups. These results suggest that, in geriatric surgical patients, the adjuvant administration of NSAIDs does not adversely affect renal function. IMPLICATIONS As determined by inulin and paraaminohippurate clearance, the intraoperative administration of diclofenac does not decrease glomerular filtration rate or effective renal plasma flow in normovolemic geriatric patients. Therefore, diclofenac may be administered during the perioperative period.
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Affiliation(s)
- B Fredman
- Department of Anesthesiology and Intensive Care, Meir Hospital, Kfar Saba, Israel
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46
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Plum J, Bünten B, Németh R, Grabensee B. Effects of the angiotensin II antagonist valsartan on blood pressure, proteinuria, and renal hemodynamics in patients with chronic renal failure and hypertension. J Am Soc Nephrol 1998; 9:2223-34. [PMID: 9848776 DOI: 10.1681/asn.v9122223] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.0] [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: 11/03/2022] Open
Abstract
Angiotensin II receptor antagonists have become clinically available for the treatment of arterial hypertension. Presently, there is little information about their effects on BP, proteinuria, and renal function in patients with moderate or advanced renal failure. This study examines the effects of the angiotensin II antagonist Valsartan (80 mg/d) on proteinuria and glomerular permselectivity in patients with chronic renal failure during a 6-mo treatment, using a double-blind, randomized, placebo-controlled study (treatment group [V-group]: n = 5, age 57 +/- 7 yr, serum creatinine 365 +/- 122 micromol/L; placebo group [P-group]: n = 4, age 62 +/- 11 yr, serum creatinine 346 +/- 61 micromol/L). Study parameters included BP, 24-h proteinuria, GFR, and effective renal plasma flow (ERPF) as determined by inulin and para-aminohippurate clearance. Changes in glomerular permselectivity were assessed by measuring the fractional clearances of neutral dextrans by HPLC gel-permeation chromatography. Valsartan lowered the mean arterial pressure on average by 13 +/- 7 mmHg during the 6-mo treatment (P < 0.05). GFR and ERPF remained almost unchanged. However, after 6 mo of Valsartan treatment, proteinuria was reduced by 396 +/- 323 mg/24 h (26 +/- 18%) and albuminuria by 531 +/- 499 mg/24 h (41 +/- 21%) with regard to baseline values (P < 0.05). In the P-group, both proteinuria and albuminuria increased slightly with time (by 30 +/- 43% and 30 +/- 54%, respectively, NS). The fractional clearances of high molecular weight dextrans >66 A were significantly reduced after 6 mo of Valsartan treatment (P < 0.05), indicating a reduction of the glomerular shunt volume by 54 +/- 20% (P < 0.05) according to the model of Deen et al. (Am J Physiol 249: 347-389, 1985). The mean pore size radius of the glomerular membrane remained unchanged. This effect was independent of glomerular hemodynamic changes. Valsartan persistently lowered proteinuria in patients with chronic renal failure. Although GFR and ERPF remained nearly stable, this effect could be attributed to an improvement in glomerular permselectivity.
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Affiliation(s)
- J Plum
- Department of Nephrology and Rheumatology, Medizinische Einrichtungen der Heinrich Heine Universität, Düsseldorf, Germany
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47
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Dehmel B, Mervaala E, Lippoldt A, Gross V, Bohlender J, Ganten D, Luft FC. Pressure-natriuresis and -diuresis in transgenic rats harboring both human renin and human angiotensinogen genes. J Am Soc Nephrol 1998; 9:2212-22. [PMID: 9848775 DOI: 10.1681/asn.v9122212] [Citation(s) in RCA: 16] [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: 11/03/2022] Open
Abstract
The hypertensive double transgenic rat harboring both the human renin and human angiotensinogen genes (dTGR) offers a unique opportunity to study the human renin-angiotensin system in an experimental animal model. Since nothing is known about the control of sodium and water excretion in these rats, this study was performed to compare pressure-natriuresis relationships in hypertensive dTGR and normotensive control rats harboring only the human renin gene (hREN), in order to determine how the pressure-natriuresis relationship is reset in hypertensive dTGR. To differentiate between extrinsic and intrinsic renal mechanisms, experiments were performed with and without renal denervation, and with and without infusions of vasopressin, norepinephrine, 17-OH-corticosterone, and aldosterone. Human and rat angiotensinogen and renin mRNA expression were also determined. In hREN without controlled renal function, urine flow and sodium excretion increased from 13 to 169 microl/min per g kidney wet weight (kwt) and from 1 to 30 micromol/min per g kwt, respectively, as renal perfusion pressure was increased from 67 to 135 mmHg. Renal blood flow (RBF) and GFR ranged between 3 to 7 and 0.9 to 1.5 ml/min per g kwt. In dTGR, pressure-natriuresis-diuresis relationships were shifted approximately 40 mmHg rightward. RBF was lower in dTGR than in hREN; GFR was not different. In dTGR with neurohormonal factors controlled, RBF was decreased and pressure-natriuresis-diuresis curves were not different compared to dTGR curves without these interventions. By light microscopy, the kidneys of these 6-wk-old dTGR and hREN rats were normal and indistinguishable. Both human and rat renin and angiotensinogen mRNA were expressed in the kidneys of dTGR. The two renin mRNA were decreased in dTGR, indicating a physiologic downregulation of renin gene expression by high BP. It is concluded that the renal pressure-natriuresis mechanism is reset toward higher pressure levels in dTGR and participates in the maintenance of hypertension. The reduced excretory function in dTGR depends on hREN and human angiotensinogen gene expression and is intrinsic to the kidney as opposed to extrarenal regulators.
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Affiliation(s)
- B Dehmel
- Franz Volhard Clinic, Medizinische Fakultät der Charité, Humboldt University of Berlin, Germany
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48
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Barthez PY, Hornof WJ, Cowgill LD, Neal LA, Mickel P. Comparison between the scintigraphic uptake and plasma clearance of 99mTc-diethylenetriaminepentacetic acid (DTPA) for the evaluation of the glomerular filtration rate in dogs. Vet Radiol Ultrasound 1998; 39:470-4. [PMID: 9771601 DOI: 10.1111/j.1740-8261.1998.tb01636.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [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: 11/30/2022] Open
Abstract
The scintigraphically measured percentage dose uptake of 99mTc-DTPA by the kidneys and the plasma clearance of 99mTc-DTPA have been reported to correlate well with inulin clearance. These two parameters were evaluated in seven dogs with known or suspected naturally occurring renal disease and compared to simultaneously measured renal inulin clearance. Correlation between inulin clearance and the 99mTc-DTPA plasma clearance was better (p = .0016) than the correlation between the percentage DTPA uptake by the kidney. It was concluded that measurement of 99mTc-DTPA plasma clearance is a more accurate method to estimate global glomerular filtration rate (GFR) than the percentage kidney uptake.
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Affiliation(s)
- P Y Barthez
- Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California, Davis 95616, USA
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49
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Plebani M, Dall'Amico R, Mussap M, Montini G, Ruzzante N, Marsilio R, Giordano G, Zacchello G. Is serum cystatin C a sensitive marker of glomerular filtration rate (GFR)? A preliminary study on renal transplant patients. Ren Fail 1998; 20:303-9. [PMID: 9574456 DOI: 10.3109/08860229809045115] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.4] [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: 11/13/2022] Open
Abstract
Human cystatin C is a basic low molecular mass protein (13,359 Dalton) freely filtered through the glomerulus and almost completely re-absorbed and catabolized by proximal tubular cells. We measured serum cystatin C in 38 kidney transplant patients (23 males, 15 females) aged between 6 and 32 years. To assess renal function, serum and urinary creatinine were also determined in all patients, and creatinine clearance was finally calculated. Cystatin C was determined by a particle-enhanced turbidimetric assay, and creatinine was measured by gas chromatography-mass spectrometry. To compare the diagnostic efficiency of cystatin C with that of creatinine, inulin clearance was performed on 12 renal transplant patients, and receiver operating characteristic (ROC) analysis was applied. The results of this study demonstrate that serum cystatin C significantly increases in renal transplant patients with reduced creatinine clearance (< 70 mL/min per 1.73 m2) and that the diagnostic accuracy of serum cystatin C is better than of serum creatinine. Cystatin C may be utilized as a very marker of reduced GFR.
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Affiliation(s)
- M Plebani
- Department of Laboratory Medicine, Central Laboratory, Azienda Ospedaliera, Padova, Italy
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50
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Pritchard G, Lyons D, Webster J, Petrie JC, MacDonald TM. Do trandolapril and indomethacin influence renal function and renal functional reserve in hypertensive patients? Br J Clin Pharmacol 1997; 44:145-9. [PMID: 9278199 PMCID: PMC2042818 DOI: 10.1046/j.1365-2125.1997.00632.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [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: 02/05/2023] Open
Abstract
AIMS To assess the effect of trandolapril (2 mg once daily) and indomethacin (25 mg three times daily), alone and in combination, on renal function and renal functional reserve in hypertensive patients (DBP 95-115 mmHg) requiring regular non-steroidal anti-inflammatory drugs (NSAIDs). METHODS Randomized, double-blind, placebo-controlled, four way crossover design. After 3 weeks treatment renal plasma flow (RPF) and glomerular filtration rate (GFR) were measured using the p-aminohippurate (PAH) and inulin methods. Renal functional reserve was estimated by measuring RPF and GFR at the end of an intravenous infusion of dopamine 2 microg kg(-1) and 10% amino acid solution. RESULTS There was no significant difference in RPF between treatments: -22.79 ml min(-1) (95% CI -54.82, 9.24) for placebo and trandolapril, -10.37 ml min(-1) (95% CI -30.7, 9.96) for placebo and indomethacin, -14.78 ml min(-1) (95% CI -50.33, 20.77) for placebo and trandolapril with indomethacin. There was no significant difference in functional reserve RPF between treatments: -34.96 ml min(-1) (95% CI -119.8, 49.88) for placebo and trandolapril, 29.78 ml min(-1), -15.18, 74.74) for placebo and indomethacin, and -25.84 ml min(-1) (95% CI -87.62, 35.94) for placebo and trandolapril with indomethacin. There was no significant difference in GFR between treatments: -1.01 ml min(-1) (95% CI -7.45, 5.42) for placebo and trandolapril, -7.88 ml min(-1) (95% CI -15.08, -0.68) for placebo and indomethacin, and -0.36 ml min(-1) (95% CI -7.58, 6.86) for placebo and trandolapril with indomethacin. There was no significant difference in functional reserve GFR between treatments: 5.13 ml min(-1) (95% CI -4.97, 15.23) for placebo and trandolapril, 6.31 ml min(-1) (95% CI -1.88, 14.5) for placebo and indomethacin, 7.21 ml min(-1) (95% CI 1.26, 13.16) for placebo and trandolapril with indomethacin. CONCLUSION In hypertensives chronic treatment with NSAIDs or ACEI alone or in combination did not change RPF or GFR and did not change renal functional reserve capacity of RPF or GFR.
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Affiliation(s)
- G Pritchard
- Clinical Pharmacology Unit, University of Aberdeen, Foresterhill, UK
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