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McArdle Z, Schreuder MF, Moritz KM, Denton KM, Singh RR. Physiology and Pathophysiology of Compensatory Adaptations of a Solitary Functioning Kidney. Front Physiol 2020; 11:725. [PMID: 32670095 PMCID: PMC7332829 DOI: 10.3389/fphys.2020.00725] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 06/03/2020] [Indexed: 12/15/2022] Open
Abstract
Children born with a solitary functioning kidney (SFK) have an increased risk of hypertension and kidney disease from early in adulthood. In response to a reduction in kidney mass, the remaining kidney undergoes compensatory kidney growth. This is associated with both an increase in size of the kidney tubules and the glomeruli and an increase in single nephron glomerular filtration rate (SNGFR). The compensatory hypertrophy and increase in filtration at the level of the individual nephron results in normalization of total glomerular filtration rate (GFR). However, over time these same compensatory mechanisms may contribute to kidney injury and hypertension. Indeed, approximately 50% of children born with a SFK develop hypertension by the age of 18 and 20–40% require dialysis by the age of 30. The mechanisms that result in kidney injury are only partly understood, and early biomarkers that distinguish those at an elevated risk of kidney injury are needed. This review will outline the compensatory adaptations to a SFK, and outline how these adaptations may contribute to kidney injury and hypertension later in life. These will be based largely on the mechanisms we have identified from our studies in an ovine model of SFK, that implicate the renal nitric oxide system, the renin angiotensin system and the renal nerves to kidney disease and hypertension associated with SFK. This discussion will also evaluate current, and speculate on next generation, prognostic factors that may predict those children at a higher risk of future kidney disease and hypertension.
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Affiliation(s)
- Zoe McArdle
- Cardiovascular Program, Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Melbourne, VIC, Australia
| | - Michiel F Schreuder
- Department of Pediatric Nephrology, Amalia Children's Hospital, Radboud University Medical Center, Nijmegen, Netherlands
| | - Karen M Moritz
- Child Health Research Centre and School of Biomedical Sciences, University of Queensland, Brisbane, QLD, Australia
| | - Kate M Denton
- Cardiovascular Program, Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Melbourne, VIC, Australia
| | - Reetu R Singh
- Cardiovascular Program, Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Melbourne, VIC, Australia
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Singh L, Arya A, Gupta S. Role of atrial natriuretic peptide in controlling diabetic nephropathy in rats. J Basic Clin Physiol Pharmacol 2018; 29:499-505. [PMID: 29672270 DOI: 10.1515/jbcpp-2017-0146] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2017] [Accepted: 03/17/2018] [Indexed: 06/08/2023]
Abstract
Abstract
Background
Diabetes is a downregulator of atrial natriuretic peptide (ANP), resulting in reduced nitric oxide level and low expression of endothelial nitric oxide synthase by which nitric oxide level get reduced. In the present study, we examined the role of ANP in reduced nitric oxide level, which may be responsible in controlling diabetic nephropathy in rats.
Methods
Serum nitrite/nitrate ratio, blood urea nitrogen, protein in urine, urinary output, serum creatinine, serum cholesterol, kidney weight, kidney hypertrophy, renal cortical collagen content, thiobarbituric acid level, and antioxidant enzymatic activities were assessed.
Results
Treatment with lisinopril (1 mg/kg) significantly attenuated diabetes-induced elevated glucose level, cholesterol level, and protein in urine concentration. Whereas ANP at low dose (5 μg/kg) has no effect on elevated markers of diabetic nephropathy, treatment with intermediate (10 μg/kg) and high-dose ANP (20 μg/kg) significantly attenuated the diabetes-induced increased blood urea nitrogen, protein in urine, urinary output, creatinine, cholesterol, kidney weight, kidney hypertrophy, renal collagen content, and thiobarbituric acid level and reduced endogenous antioxidant enzymatic activities. High dose of ANP was more effective in attenuating the diabetes-induced nephropathy, renal oxidative stress, and antioxidant enzyme activity as compared with the treatment with low-dose ANP (5 μg/kg), intermediate-dose ANP (10 μg/kg), or lisinopril (1 mg/kg, employed as standard agent). Administration of erythro-9-(2-hydroxy-3-nonyl)adenine, a phosphodiesterase-2 inhibitor (3 mg/kg), in combination with high-dose ANP significantly attenuated high-dose ANP induced ameliorative effects in diabetic nephropathy.
Conclusions
Taken together, these results indicate that diabetes-induced oxidative stress and lipid alterations may be responsible for the induction of nephropathy in diabetic rats. ANP at intermediate and high doses have prevented the development of diabetes-induced nephropathy by reducing the cholesterol level, protein in urine concentration, and renal oxidative stress and by increasing the nitrite/nitrate ratio, certainly providing the direct nephroprotective action.
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Affiliation(s)
- Lakhwinder Singh
- Department of Applied Science, Chandigarh Group of Colleges, College of Engineering, Landran, Punjab, India
| | - Atul Arya
- Inder Kumar Gujral Punjab Technical University, Jalandhar, Punjab 144603, India, Phone: +919779981111
| | - Sumeet Gupta
- Department of Pharmacology, Maharishi Markandeshwar University, Mullana, Haryana, India
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Abstract
Plasma prekallikrein is the liver-derived precursor of the trypsin-like serine protease plasma kallikrein, and circulates in plasma bound to high molecular weight kininogen. Plasma prekallikrein is activated to plasma kallikrein by activated factor XII or prolylcarboxypeptidase. Plasma kallikrein regulates the activity of multiple proteolytic cascades in the cardiovascular system such as the intrinsic pathway of coagulation, the kallikrein-kinin system, the fibrinolytic system, the renin-angiotensin system, and the complement pathways. As such, plasma kallikrein plays a central role in the pathogenesis of thrombosis, inflammation, and blood pressure regulation. Under physiological conditions, plasma kallikrein serves as a cardioprotective enzyme. However, its increased plasma concentration or hyperactivity perpetuates cardiovascular disease (CVD). In this article, we review the biochemistry and cell biology of plasma kallikrein and summarize data from preclinical and clinical studies that have established important functions of this serine protease in CVD states. Finally, we propose plasma kallikrein inhibitors as a novel class of drugs with potential therapeutic applications in the treatment of CVDs.
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Zhou C, Yool AJ, Byard RW. Armanni-Ebstein Lesions in Terminal Hyperglycemia. J Forensic Sci 2016; 62:921-925. [DOI: 10.1111/1556-4029.13360] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Accepted: 09/20/2016] [Indexed: 11/26/2022]
Affiliation(s)
- Chong Zhou
- The University of Adelaide Medical School; Frome Road Adelaide SA 5005 Australia
- Forensic Science SA; 21 Divett Place Adelaide SA 5000 Australia
| | - Andrea J. Yool
- School of Medicine; University of Adelaide; Frome Road Adelaide SA 5005 Australia
| | - Roger W. Byard
- Forensic Science SA; 21 Divett Place Adelaide SA 5000 Australia
- School of Medicine; University of Adelaide; Frome Road Adelaide SA 5005 Australia
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Persson P, Fasching A, Teerlink T, Hansell P, Palm F. Cellular transport of l-arginine determines renal medullary blood flow in control rats, but not in diabetic rats despite enhanced cellular uptake capacity. Am J Physiol Renal Physiol 2016; 312:F278-F283. [PMID: 27927650 DOI: 10.1152/ajprenal.00335.2016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Revised: 11/29/2016] [Accepted: 11/29/2016] [Indexed: 11/22/2022] Open
Abstract
Diabetes mellitus is associated with decreased nitric oxide bioavailability thereby affecting renal blood flow regulation. Previous reports have demonstrated that cellular uptake of l-arginine is rate limiting for nitric oxide production and that plasma l-arginine concentration is decreased in diabetes. We therefore investigated whether regional renal blood flow regulation is affected by cellular l-arginine uptake in streptozotocin-induced diabetic rats. Rats were anesthetized with thiobutabarbital, and the left kidney was exposed. Total, cortical, and medullary renal blood flow was investigated before and after renal artery infusion of increasing doses of either l-homoarginine to inhibit cellular uptake of l-arginine or Nω-nitro- l-arginine methyl ester (l-NAME) to inhibit nitric oxide synthase. l-Homoarginine infusion did not affect total or cortical blood flow in any of the groups, but caused a dose-dependent reduction in medullary blood flow. l-NAME decreased total, cortical and medullary blood flow in both groups. However, the reductions in medullary blood flow in response to both l-homoarginine and l-NAME were more pronounced in the control groups compared with the diabetic groups. Isolated cortical tubular cells displayed similar l-arginine uptake capacity whereas medullary tubular cells isolated from diabetic rats had increased l-arginine uptake capacity. Diabetics had reduced l-arginine concentrations in plasma and medullary tissue but increased l-arginine concentration in cortical tissue. In conclusion, the reduced l-arginine availability in plasma and medullary tissue in diabetes results in reduced nitric oxide-mediated regulation of renal medullary hemodynamics. Cortical blood flow regulation displays less dependency on extracellular l-arginine and the upregulated cortical tissue l-arginine may protect cortical hemodynamics in diabetes.
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Affiliation(s)
- Patrik Persson
- Division of Integrative Physiology, Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden; and
| | - Angelica Fasching
- Division of Integrative Physiology, Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden; and
| | - Tom Teerlink
- Department of Clinical Chemistry, VU University Medical Center, Amsterdam, The Netherlands
| | - Peter Hansell
- Division of Integrative Physiology, Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden; and
| | - Fredrik Palm
- Division of Integrative Physiology, Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden; and
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Preetha PP, Devi VG, Rajamohan T. Mature coconut water exhibits antidiabetic and antithrombotic potential via L-arginine-nitric oxide pathway in alloxan induced diabetic rats. J Basic Clin Physiol Pharmacol 2015; 26:575-583. [PMID: 26146124 DOI: 10.1515/jbcpp-2014-0126] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Accepted: 05/05/2015] [Indexed: 06/04/2023]
Abstract
BACKGROUND The aims of the present study were to assess whether the antidiabetic activity of mature coconut water (MCW) is mediated through L-arginine-nitric oxide pathway in diabetic rats, and to study the effects of MCW on blood coagulation. METHODS Diabetes was induced in male Sprague-Dawley rats by injecting them with alloxan (150 mg/kg body weight). MCW (4 mL/100 g body weight) and L-arginine (7.5 mg/100 g body weight) was given orally for 45 days. L-NAME was given at a dose of 0.5 mg/kg body weight. Concentrations of blood glucose, plasma insulin, glycosylated hemoglobin (HbA1c), L-arginine, urine volume and urinary creatinine levels, activity of nitric oxide synthase (NOS), and arginase as well as the abnormalities in hemostasis and thrombosis were measured in all the experimental groups. RESULTS Treatment with MCW and L-arginine reduced the concentration of blood glucose and HbA1c in diabetic rats. MCW and L-arginine treatment exhibited significant antithrombotic activity in diabetic rats, which was evident from the reduced levels of WBC, platelets, fibrin, and fibrinogen. MCW and L-arginine treatment prolonged the prothrombin time in diabetic rats and reduced the activity of Factor V. In addition to this, the activity of nitric oxide synthase, liver and plasma arginine content, and urinary nitrite were higher in MCW-treated diabetic rats whereas L-NAME treatment inhibited the beneficial effects induced by MCW and arginine. CONCLUSIONS The results clearly indicate that L-arginine is a major factor responsible for the antidiabetic and antithrombotic potential of coconut water, and is mediated through the L-arginine-nitric oxide pathway.
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Kandhare AD, Patil MVK, Bodhankar SL. l-Arginine attenuates the ethylene glycol induced urolithiasis in ininephrectomized hypertensive rats: role of KIM-1, NGAL, and NOs. Ren Fail 2015; 37:709-21. [DOI: 10.3109/0886022x.2015.1011967] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
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Dietary Management of Diabetic Chronic Kidney Disease. Curr Nutr Rep 2014. [DOI: 10.1007/s13668-014-0093-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Mahdavifard S, Bathaie S, Nakhjavani M, Heidarzadeh H. l-cysteine is a potent inhibitor of protein glycation on both albumin and LDL, and prevents the diabetic complications in diabetic–atherosclerotic rat. Food Res Int 2014. [DOI: 10.1016/j.foodres.2014.05.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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10
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Persson P, Fasching A, Teerlink T, Hansell P, Palm F. l
-Citrulline, But Not
l
-Arginine, Prevents Diabetes Mellitus–Induced Glomerular Hyperfiltration and Proteinuria in Rat. Hypertension 2014; 64:323-9. [DOI: 10.1161/hypertensionaha.114.03519] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Diabetes mellitus–induced oxidative stress causes increased renal oxygen consumption and intrarenal tissue hypoxia. Nitric oxide is an important determinant of renal oxygen consumption and electrolyte transport efficiency. The present study investigates whether
l
-arginine or
l
-citrulline to promote nitric oxide production prevents the diabetes mellitus–induced kidney dysfunction. Glomerular filtration rate, renal blood flow, in vivo oxygen consumption, tissue oxygen tension, and proteinuria were investigated in control and streptozotocin-diabetic rats with and without chronic
l
-arginine or
l
-citrulline treatment for 3 weeks. Untreated and
l
-arginine–treated diabetic rats displayed increased glomerular filtration rate (2600±162 versus 1599±127 and 2290±171 versus 1739±138 µL/min per kidney), whereas
l
-citrulline prevented the increase (1227±126 versus 1375±88 µL/min per kidney). Filtration fraction was increased in untreated diabetic rats because of the increase in glomerular filtration rate but not in
l
-arginine– or
l
-citrulline–treated diabetic rats. Urinary protein excretion was increased in untreated and
l
-arginine–treated diabetic rats (142±25 versus 75±7 and 128±7 versus 89±7 µg/min per kidney) but not in diabetic rats administered
l
-citrulline (67±7 versus 61±5 µg/min per kidney). The diabetes mellitus–induced tissue hypoxia, because of elevated oxygen consumption, was unaltered by any of the treatments.
l
-citrulline administered to diabetic rats increases plasma
l
-arginine concentration, which prevents the diabetes mellitus–induced glomerular hyperfiltration, filtration fraction, and proteinuria, possibly by a vascular effect.
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Affiliation(s)
- Patrik Persson
- From the Division of Integrative Physiology, Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden (P.P., A.F., P.H., F.P.); Department of Clinical Chemistry, VU University Medical Center, Amsterdam, The Netherlands (T.T.); and Division of Drug Research, Department of Medical and Health Sciences (F.P.) and Center for Medical Image Science and Visualization (F.P.), Linköping University, Linköping, Sweden
| | - Angelica Fasching
- From the Division of Integrative Physiology, Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden (P.P., A.F., P.H., F.P.); Department of Clinical Chemistry, VU University Medical Center, Amsterdam, The Netherlands (T.T.); and Division of Drug Research, Department of Medical and Health Sciences (F.P.) and Center for Medical Image Science and Visualization (F.P.), Linköping University, Linköping, Sweden
| | - Tom Teerlink
- From the Division of Integrative Physiology, Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden (P.P., A.F., P.H., F.P.); Department of Clinical Chemistry, VU University Medical Center, Amsterdam, The Netherlands (T.T.); and Division of Drug Research, Department of Medical and Health Sciences (F.P.) and Center for Medical Image Science and Visualization (F.P.), Linköping University, Linköping, Sweden
| | - Peter Hansell
- From the Division of Integrative Physiology, Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden (P.P., A.F., P.H., F.P.); Department of Clinical Chemistry, VU University Medical Center, Amsterdam, The Netherlands (T.T.); and Division of Drug Research, Department of Medical and Health Sciences (F.P.) and Center for Medical Image Science and Visualization (F.P.), Linköping University, Linköping, Sweden
| | - Fredrik Palm
- From the Division of Integrative Physiology, Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden (P.P., A.F., P.H., F.P.); Department of Clinical Chemistry, VU University Medical Center, Amsterdam, The Netherlands (T.T.); and Division of Drug Research, Department of Medical and Health Sciences (F.P.) and Center for Medical Image Science and Visualization (F.P.), Linköping University, Linköping, Sweden
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Abstract
The long-term complications of diabetes are characterized by pathologic changes in both the microvasculature and conduit vessels. Although the fenestrated glomerular endothelium classically has been viewed as providing little in the way of an impediment to macromolecular flow, increasing evidence illustrates that this is not the case. Rather, hyperglycemia-mediated endothelial injury may predispose to albuminuria in diabetes both through direct effects and through bidirectional communication with neighboring podocytes. Although neo-angiogenesis of the glomerular capillaries may be a feature of early diabetes, particularly in the experimental setting, loss of capillaries in the glomerulus and in the interstitium are key events that each correlate closely with declining glomerular filtration rate in patients with diabetic nephropathy. The hypoxic milieu that follows the microvascular rarefaction provides a potent stimulus for fibrogenesis, leading to the glomerulosclerosis and tubulointerstitial fibrosis that characterize advanced diabetic kidney disease. Given the pivotal role the endothelium plays in both the development and the progression of diabetic nephropathy we need effective strategies that prevent its loss or accelerate its regeneration. Such advances likely will lead not only to improved tissue oxygenation and reduced fibrosis, but also to improved long-term renal function.
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Affiliation(s)
- Andrew Advani
- Keenan Research Centre of the Li Ka Shing Knowledge Institute, St. Michael's Hospital, and Department of Medicine, University of Toronto, Toronto, Ontario, Canada.
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12
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Abstract
Diabetic nephropathy is the major cause of end-stage renal disease worldwide. Although the renin-angiotensin system has been implicated in the pathogenesis of diabetic nephropathy, angiotensin I-converting enzyme inhibitors have a beneficial effect on diabetic nephropathy independently of their effects on blood pressure and plasma angiotensin II levels. This suggests that the kallikrein-kinin system (KKS) is also involved in the disease. To study the role of the KKS in diabetic nephropathy, mice lacking either the bradykinin B1 receptor (B1R) or the bradykinin B2 receptor (B2R) have been commonly used. However, because absence of either receptor causes enhanced expression of the other, it is difficult to determine the precise functions of each receptor. This difficulty has recently been overcome by comparing mice lacking both receptors with mice lacking each receptor. Deletion of both B1R and B2R reduces nitric oxide (NO) production and aggravates renal diabetic phenotypes, relevant to either lack of B1R or B2R, demonstrating that both B1R and B2R exert protective effects on diabetic nephropathy presumably via NO. Here, we review previous epidemiological and experimental studies, and discuss novel insights regarding the therapeutic implications of the importance of the KKS in averting diabetic nephropathy.
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Burke SD, Barrette VF, David S, Khankin EV, Adams MA, Croy BA. Circulatory and renal consequences of pregnancy in diabetic NOD mice. Placenta 2011; 32:949-55. [PMID: 22014504 DOI: 10.1016/j.placenta.2011.09.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Revised: 09/23/2011] [Accepted: 09/27/2011] [Indexed: 12/01/2022]
Abstract
OBJECTIVES Women with diabetes have elevated gestational risks for severe hemodynamic complications, including preeclampsia in mid- to late pregnancy. This study employed continuous, chronic radiotelemetry to compare the hemodynamic patterns in non-obese diabetic (NOD) mice who were overtly diabetic or normoglycemic throughout gestation. We hypothesized that overtly diabetic, pregnant NOD mice would develop gestational hypertension and provide understanding of mechanisms in progression of this pathology. STUDY DESIGN Telemeter-implanted, age-matched NOD females with and without diabetes were assessed for six hemodynamic parameters (mean, systolic, diastolic, pulse pressures, heart rate and activity) prior to mating, over pregnancy and over a 72 h post-partum interval. Urinalysis, serum biochemistry and renal histopathology were also conducted. RESULTS Pregnant, normoglycemic NOD mice had a hemodynamic profile similar to other inbred strains, despite insulitis. This pattern was characterized by an interval of pre-implantation stability, post implantation decline in arterial pressure to mid gestation, and then a rebound to pre-pregnancy baseline during later gestation. Overtly diabetic NOD mice had a blood pressure profile that was normal until mid-gestation then become mildly hypotensive (-7 mmHg, P < 0.05), severely bradycardic (-80 bpm, P < 0.01) and showed signs of acute kidney injury. Pups born to diabetic dams were viable but growth restricted, despite their mothers' failing health, which did not rebound post-partum (-10% pre-pregnancy pressure and HR, P < 0.05). CONCLUSIONS Pregnancy accelerates circulatory and renal pathologies in overtly diabetic NOD mice and is characterized by depressed arterial pressure from mid-gestation and birth of growth-restricted offspring.
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Affiliation(s)
- S D Burke
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario K7L 3N6, Canada
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Kuno Y, Iyoda M, Shibata T, Hirai Y, Akizawa T. Sildenafil, a phosphodiesterase type 5 inhibitor, attenuates diabetic nephropathy in non-insulin-dependent Otsuka Long-Evans Tokushima Fatty rats. Br J Pharmacol 2011; 162:1389-400. [PMID: 21133896 DOI: 10.1111/j.1476-5381.2010.01149.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND It is well established that the pathogenesis of diabetic nephropathy is associated with abnormalities of renal nitric oxide (NO) generation. Many of the biological actions of NO are mediated by cGMP, which is rapidly degraded by phosphodiesterases. In this study, we evaluated the renoprotective effects of sildenafil (SIL), an inhibitor of phosphodiesterase-5, in type 2 diabetic rats. METHODS Male Otsuka Long-Evans Tokushima Fatty (OLETF) rats, a non-insulin-dependent diabetes model, and Long-Evans Tokushima Otsuka rats, a non-diabetic control, were treated with either SIL (2.5 mg·kg(-1) in drinking water) or undosed water for 28 weeks, starting at 30 weeks of age. RESULTS Sildenafil treatment significantly decreased albuminuria, attenuated glomerular hyperfiltration and resulted in a decrease in glomerular hypertrophy, in addition to a reduced glomerulosclerosis score and a dramatic decrease in the number of glomerular and tubulointerstitial proliferating cell nuclear antigen-positive cells in OLETF rats. This was accompanied by a significant reduction in renal cortical mRNA levels of collagen types I and III. The increased mRNA levels of matrix metalloproteinase (MMP)-2, MMP-9, tissue inhibitors of MMPs (TIMP)-1 and TIMP-2 in the OLETF rats were significantly or partially attenuated by SIL treatment. CONCLUSIONS This study suggests that SIL attenuated diabetic nephropathy due to its potent antiproliferative effects and its regulatory effects on extracellular matrix. This latter effect is thought to be a result of its ability to affect the balance between MMPs and their inhibitors.
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Affiliation(s)
- Yoshihiro Kuno
- Division of Nephrology, Department of Medicine, Showa University School of Medicine, Shinagawa-ku, Tokyo, Japan
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15
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Arellano-Mendoza MG, Vargas-Robles H, Del Valle-Mondragon L, Rios A, Escalante B. Prevention of renal injury and endothelial dysfunction by chronic L-arginine and antioxidant treatment. Ren Fail 2011; 33:47-53. [PMID: 21219205 DOI: 10.3109/0886022x.2010.541583] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
We evaluated the effects of vitamins with antioxidant properties (a combination of vitamins C and E) and L-arginine treatment on renal failure in mice by measuring survival rate. The molecular changes were elucidated by determining endothelial tetrahydrobiopterin (BH4) levels and nitric oxide synthase (eNOS) mRNA expression in mice with renal ablation. Previous studies have shown that endothelial dysfunction in 5/6 nephrectomized mice is associated with decreased nitric oxide (NO) bioavailability and increased vascular superoxide production. WTC57 mice were divided into three groups: Group 1 was the sham-operated group (C); Group 2 was the 5/6 nephrectomized group (Nfx); and Group 3 was a group of 5/6 nephrectomized mice, treated with L-arginine and vitamins with antioxidant properties (NfxTx; 200 mg/kg L-arginine, 83 mg/kg vitamin C, and 46.6 mg/kg vitamin E). After 20 weeks of treatment, urinary protein excretion, blood pressure, BH4 and dihydrobiopterin (BH2) levels, eNOS mRNA, oxidative stress, and survival rate were determined. An increase in urinary protein excretion, blood pressure, and oxidative stress was prevented in the NfxTx group, but not in the Nfx group. BH4 and eNOS mRNA expression was increased by 32% and 78%, respectively, in the NfxTx group. Furthermore, the treatment increased the survival rate by 33%. Our results indicate that under normal conditions, NO appears to protect renal function. However, this NO-dependent protection is lost during kidney failure, probably due to increased reactive oxygen species synthesis. The treatment restores the viability of NO and prevents the BH4 oxidation. Therefore, this treatment may represent a therapeutic approach for the management of kidney disease.
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16
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Effects of dietary arginine on inflammatory mediator and receptor of advanced glycation endproducts (RAGE) expression in rats with streptozotocin-induced type 2 diabetes. Br J Nutr 2010; 104:686-92. [DOI: 10.1017/s000711451000111x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Arginine (Arg) is known to possess numerous useful physiological properties and have immunomodulatory effects.In vitrostudies reported that Arg inhibits advanced glycation endproduct (AGE) formation; however, the effects of Arg on the receptor of AGE (RAGE) expression in inflammatory conditions are not clear. The present study investigated the effects of dietary Arg supplementation on inflammatory mediator production and RAGE expression in type 2 diabetic rats. There were one normal control (NC) group and two diabetic groups in the present study. Rats in the NC group were fed with a regular chow diet. One diabetic group (DM) was fed a common semi-purified diet while the other diabetic group received a diet in which part of the casein was replaced by Arg (DM-Arg) for 8 weeks. Diabetes was induced by an intraperitoneal injection of nicotinamide followed by streptozotocin. Rats with blood glucose levels exceeding 1800 mg/l were considered diabetic. Blood samples and the liver and lungs of the animals were collected at the end of the study for further analysis. Results showed that plasma glucose and fructosamine contents were significantly higher in the diabetic groups than those in the NC group. The DM group had higher fructosamine and C-reactive protein than the DM-Arg group. Immunohistochemical staining showed that the expressions of RAGE in liver and lung tissues were significantly lower in the DM-Arg group than in the DM group. These results suggest that supplemental dietary Arg can decrease AGE–RAGE interactions and consequently reduce tissue damage in rats with type 2 diabetes.
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17
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Supplemental dietary arginine reduces renal RAGE expression and oxidative damage in rats with streptozotocin-induced type 2 diabetes. ACTA ACUST UNITED AC 2010. [DOI: 10.1016/j.eclnm.2010.02.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Ozeki M, Nagasu H, Satoh M, Namikoshi T, Haruna Y, Tomita N, Sasaki T, Kashihara N. Reactive oxygen species mediate compensatory glomerular hypertrophy in rat uninephrectomized kidney. J Physiol Sci 2009; 59:397-404. [PMID: 19593678 PMCID: PMC10717616 DOI: 10.1007/s12576-009-0048-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2009] [Accepted: 06/09/2009] [Indexed: 11/24/2022]
Abstract
Hyperfiltration in glomeruli is the most common pathway to progressive renal dysfunction. Moreover, reduction of renal mass by unilateral nephrectomy results in an immediate increase in glomerular flow to the remnant kidney, followed by compensatory glomerular hypertrophy. Reactive oxygen species (ROS) are involved in renal hypertrophic responses; however, the role of ROS in compensatory glomerular hypertrophy remains unclear. Therefore, this role was investigated in the present study. Wistar rats were randomly placed into two groups: uninephrectomized rats (Nx) and uninephrectomized rats treated with tempol (Nx + TP). The glomerular volume increased in the Nx 1 week after surgery, but was significantly suppressed in the Nx + TP. Levels of phospho-Akt and phospho-ribosomal protein S6, which are critical for cell growth and hypertrophy, were markedly increased in the glomeruli of the Nx, while tempol treatment almost abolished the activation of these proteins. These results suggest that ROS have important roles in compensatory hypertrophy in glomeruli.
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Affiliation(s)
- Masahito Ozeki
- Division of Nephrology, Department of Internal Medicine, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama 701-0192 Japan
| | - Hajime Nagasu
- Division of Nephrology, Department of Internal Medicine, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama 701-0192 Japan
| | - Minoru Satoh
- Division of Nephrology, Department of Internal Medicine, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama 701-0192 Japan
| | - Tamehachi Namikoshi
- Division of Nephrology, Department of Internal Medicine, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama 701-0192 Japan
| | - Yoshisuke Haruna
- Division of Nephrology, Department of Internal Medicine, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama 701-0192 Japan
| | - Naruya Tomita
- Division of Nephrology, Department of Internal Medicine, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama 701-0192 Japan
| | - Tamaki Sasaki
- Division of Nephrology, Department of Internal Medicine, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama 701-0192 Japan
| | - Naoki Kashihara
- Division of Nephrology, Department of Internal Medicine, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama 701-0192 Japan
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Hill-Kapturczak N, Kapturczak MH, Malinski T, Gross P. Nitric Oxide and Nitric Oxide Synthase in the Kidney: Potential Roles in Normal Renal Function and in Renal Dysfunction. ACTA ACUST UNITED AC 2009. [DOI: 10.3109/10623329509024671] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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20
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Piacenza F, Malavolta M, Cipriano C, Costarelli L, Giacconi R, Muti E, Tesei S, Pierpaoli S, Basso A, Bracci M, Bonacucina V, Santarelli L, Mocchegiani E. l-Arginine normalizes NOS activity and zinc-MT homeostasis in the kidney of mice chronically exposed to inorganic mercury. Toxicol Lett 2009; 189:200-5. [PMID: 19501138 DOI: 10.1016/j.toxlet.2009.05.021] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2009] [Revised: 05/22/2009] [Accepted: 05/25/2009] [Indexed: 11/15/2022]
Abstract
Inorganic mercury (HgCl2) exposure provokes damage in many organs, especially kidney. Inducible nitric oxide synthase (iNOS) expression, total NOS activity and the profiles of zinc (Zn), copper (Cu) and Hg as well as their distribution when bound to specific intracellular proteins, including metallothioneins (MT), were studied during HgCl2 exposure and after l-arginine treatment in C57BL/6 mouse kidney. HgCl2 exposure modulates differently iNOS expression and NOS activity, increasing iNOS expression but, conversely, decreasing total NOS activity in the mouse kidney. Moreover, during Hg exposure an increased MT production occurs. The kidney damage leads to a loss of urinary proteins, increased plasma creatinine and high Zn mobilization with consequent increased urinary Zn excretion. l-arginine treatment recovers NOS activity and induces a normalization of MT induction, plasma creatinine values and urinary proteins excretion, suggesting that l-arginine may limit kidney damages by Hg exposure.
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Affiliation(s)
- Francesco Piacenza
- Department of Molecular Pathology and Innovative Therapies, Occupational Medicine, Polytechnic University of Marche, Torrette, Ancona, Italy
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21
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Kakoki M, Smithies O. The kallikrein-kinin system in health and in diseases of the kidney. Kidney Int 2009; 75:1019-30. [PMID: 19190676 DOI: 10.1038/ki.2008.647] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Since kallikrein was discovered as a vasodilatory substance in human urine, the kallikrein-kinin system (KKS) has been considered to play a physiological role in controlling blood pressure. Gene targeting experiments in mice in which the KKS has been inactivated to varying degrees have, however, questioned this role, because basal blood pressures are not altered. Rather, these experiments have shown that the KKS has a different and important role in preventing changes associated with normal senescence in mice, and in reducing the nephropathy and accelerated senescence-associated phenotypes induced in mice by diabetes. Other experiments have shown that the KKS suppresses mitochondrial respiration, partly by nitric oxide and prostaglandins, and that this suppression may be a key to understanding how the KKS influences senescence-related diseases. Here we review the logical progression and experimental data leading to these conclusions, and discuss their relevance to human conditions.
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Affiliation(s)
- Masao Kakoki
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC 27599-7525, USA.
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22
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Can rodent models of diabetic kidney disease clarify the significance of early hyperfiltration?: recognizing clinical and experimental uncertainties. Clin Sci (Lond) 2008; 114:109-18. [PMID: 18062776 DOI: 10.1042/cs20070088] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
In the past, hyperfiltration and increased glomerular capillary pressure have been identified as important determinants of the development of DN (diabetic nephropathy). Recently, some basic research and clinical reviews on DN have omitted identifying hyperfiltration as an important risk factor. At the same time, different rodent models of DN have been described without and with documented hyperfiltration. In the present review, the importance of hyperfiltration is reassessed, reviewing key clinical and research studies, including the first single nephron studies in a mouse model of DN. From clinical studies of Type 1 and Type 2 diabetes mellitus, it is clear that many patients do not have early hyperfiltration and, even when present, its contribution to subsequent DN remains uncertain. Key mechanisms underlying hyperfiltration in rodent models are reviewed. Findings on intrarenal NO metabolism and the control of single-nephron GFR (glomerular filtration rate) in rodent models of DN are also presented. Characterization of valid experimental models of DN should include a careful delineation of the absence or presence of early hyperfiltration, with special efforts made to establish the specific role hyperfiltration may play in the emergence of DN.
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Cavanal MDF, Gomes GN, Forti AL, Rocha SO, Franco MDCP, Fortes ZB, Gil FZ. The influence of L-arginine on blood pressure, vascular nitric oxide and renal morphometry in the offspring from diabetic mothers. Pediatr Res 2007; 62:145-50. [PMID: 17597655 DOI: 10.1203/pdr.0b013e318098722e] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The present study was designed to evaluate the effects of L-arginine (L-arg) supplementation on blood pressure, vascular nitric oxide content, and renal morphometry in the adult offspring from diabetic mothers. Diabetes mellitus was induced in female rats with a single dose of streptozotocin (50 mg/kg), before mating. The offspring was divided into four groups: group C (controls); group DO (diabetic offspring); group CA (controls receiving 2% L-arg solution dissolved in 2% sucrose in the drinking water) and group DA (DO receiving the L-arg solution). Oral supplementation began after weaning and continued until the end of the experiments. In DO, hypertension was observed, from 3 mo on. In DA, pressure levels were not different from C and CA. In 6-mo-old animals, basal NO production (assessed by DAF-2) was significantly depressed in DO in comparison to controls. The NO production was significantly increased after stimulation with Ach or BK in all groups, the increase being greater in control than in DO rats. L-arg was able to improve the NO production and to prevent the glomerular hypertrophy in the DO. Our data suggest that the bioavailability of NO is reduced in the DO, because L-arg corrected both the hypertension and glomerular hypertrophy.
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Affiliation(s)
- Maria de Fatima Cavanal
- Department of Physiology, Federal University of São Paulo - Unifesp/EPM, CEP 04023-900, São Paulo, Brazil
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Bellinghieri G, Santoro D, Mallamace A, Di Giorgio RM, De Luca G, Savica V. L-arginine: a new opportunity in the management of clinical derangements in dialysis patients. J Ren Nutr 2006; 16:245-7. [PMID: 16825029 DOI: 10.1053/j.jrn.2006.04.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
L-Arginine is an essential amino acid for infants and growing children, as well as for pregnant women. This amino acid is a substrate for at least 5 enzymes identified in mammals, including arginase, arginine-glycine transaminase, kyotorphine synthase, nitric oxide synthase, and arginine decarboxylase. L-arginine is essential for the synthesis of creatine, urea, polyamines, nitric oxide, and agmatine. Arginine may be considered an essential amino acid in sepsis, and its supplementation could be beneficial in this clinical setting by improving microcirculation and protein anabolism. Rats receiving arginine-supplemented parenteral nutrition showed an increased ability to synthesize acute phase proteins when challenged with sepsis. Finally, L-arginine exerts antihypertensive and antiproliferative effects on vascular smooth muscles. It has been shown to reduce systemic blood pressure in some forms of experimental hypertension. Endothelial dysfunction and reduced nitric oxide bioactivity are associated with increased incidence of cardiovascular diseases. A beneficial effect of acute and chronic L-arginine supplementation on endothelial derived nitric oxide production and endothelial function has been shown. In end-stage renal disease patients, the rate of de novo arginine synthesis seemed to be preserved. Our preliminary data on a group of dialysis patients showed that predialysis arginine levels were stable in a normal range during the dialysis session and that hypertensive patients had lower arginine-citrulline ratio than normotensive patients.
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Affiliation(s)
- Guido Bellinghieri
- Division of Nephrology and Dialysis, Facolta di Medicina e Chirugia di Messina, University of Messina, Messina, Italy.
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Kamijo H, Higuchi M, Hora K. Chronic inhibition of nitric oxide production aggravates diabetic nephropathy in Otsuka Long-Evans Tokushima Fatty rats. Nephron Clin Pract 2006; 104:p12-22. [PMID: 16691035 DOI: 10.1159/000093276] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2005] [Accepted: 02/03/2006] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Nitric oxide (NO) is known to play a role in diabetic nephropathy, but the molecular basis for this effect remains unclear. METHOD Otsuka Long-Evans Tokushima Fatty spontaneous diabetic rat models were used along with Long-Evans Tokushima Otuska rat models as age-matched controls. Either L-arginine (a NO precursor) or L-NAME (a nitric oxide synthase inhibitor) was administered from the age of 22 weeks. Clinical parameters and serum and urinary NO2+NO3 levels were measured, in addition to renal histological findings and ED-1-positive cell counts in glomeruli. RESULTS There were no significant differences in creatinine clearance between any of the groups at any point. The levels of urinary NO2+NO3 in the diabetic group were significantly lower than those in the control groups after 40 weeks; that in the L-NAME diabetic group was significantly lower than in the other diabetic groups at 52 weeks. Compared with the other diabetic groups, the L-NAME diabetic group had significantly higher urinary protein excretion levels, histological scores, and numbers of ED-1-positive cells in glomeruli. Diabetic rats administered L-arginine excreted more urinary protein than the diabetic controls. CONCLUSION Diabetic nephropathy was exacerbated drastically by a nitric oxide synthase inhibitor and mildly by a NO precursor. These data suggested that NO may modify type 2 diabetic nephropathy in Otuska Long-Evans Tokushima Fatty rats through factors other than hemodynamics.
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Affiliation(s)
- Hiroshi Kamijo
- Second Department of Internal Medicine, Shinshu University School of Medicine, Matsumoto, Nagano, Japan
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26
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McCarty MF. Adjuvant strategies for prevention of glomerulosclerosis. Med Hypotheses 2006; 67:1277-96. [PMID: 16828231 DOI: 10.1016/j.mehy.2004.11.048] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2004] [Accepted: 11/29/2004] [Indexed: 12/23/2022]
Abstract
The glomerulosclerosis which frequently complicates diabetes and severe hypertension is mediated primarily by increased mesangial production and activation of transforming growth factor-beta (TGF-beta), which acts on mesangial cells to boost their production of matrix proteins while suppressing extracellular proteolytic activity. Hyperglycemia and glomerular hypertension work in various complementary ways to stimulate superoxide production via NADPH oxidase in mesangial cells; the resulting oxidant stress results in the induction and activation of TFG-beta. Nitric oxide, generated by glomerular capillaries and by mesangial cells themselves, functions physiologically to oppose mesangial TGF-beta overproduction; however, NO bioactivity is compromised by oxidant stress. In addition to low-protein diets and drugs that suppress angiotensin II activity, a variety of other agents and measures may have potential for impeding the process of glomerulosclerosis. These include vitamin E, which blunts the rise in mesangial diacylglycerol levels induced by hyperglycemia; statins and (possibly) policosanol, which down-regulate NADPH oxidase activity by diminishing isoprenylation of Rac1; lipoic acid, whose potent antioxidant activity antagonizes the impact of oxidant stress on TGF-beta expression; pyridoxamine, which inhibits production of advanced glycation endproducts; arginine, high-dose folate, vitamin C, and salt restriction, which may support glomerular production of nitric oxide; and estrogen and soy isoflavones, which may induce nitric oxide synthase in glomerular capillaries while also interfering with TGF-beta signaling. Further research along these lines may enable the development of complex nutraceuticals which have important clinical utility for controlling and preventing glomerulosclerosis and renal failure. Most of these measures may likewise reduce risk for left ventricular hypertrophy in hypertensives, inasmuch as the signaling mechanisms which mediate this disorder appear similar to those involved in glomerulosclerosis.
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Affiliation(s)
- Mark F McCarty
- NutriGuard Research, 1051 Hermes Ave., Encinitas, CA 92024, USA.
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27
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Abstract
Diabetic nephropathy is the most frequent cause of terminal renal failure, requiring renal replacement therapy. Although a number of factors may contribute to the development of renal disease in diabetes, the recent past has witnessed an explosive growth in literature pertaining to the role of nitric oxide in diabetic nephropathy. However, there are significant controversies in the findings of these studies partly because of the complex metabolic pathways involved in the generation and fate of nitric oxide in the diabetic kidney. The following discussion presents a critical and balanced review of the current understanding of this subject.
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Affiliation(s)
- Sharma S Prabhakar
- Division of Nephrology, Department of Medicine, 3601, 4th Street, 4C-178, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA.
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Khamaisi M, Keynan S, Bursztyn M, Dahan R, Reinhartz E, Ovadia H, Raz I. Role of renal nitric oxide synthase in diabetic kidney disease during the chronic phase of diabetes. Nephron Clin Pract 2005; 102:p72-80. [PMID: 16319502 DOI: 10.1159/000089946] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2004] [Accepted: 08/17/2005] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Several studies have suggested that an early increase in renal nitric oxide (NO) production or activity mediates pathophysiologic and morphologic changes in diabetic nephropathy. To evaluate the role of NO in developing diabetic kidney disease, we studied the NO system in streptozotocin (STZ)-induced diabetic rats for a period of 8 weeks. METHODS Control rats, STZ-induced diabetic rats, and STZ-induced diabetic rats treated with insulin were monitored and sacrificed at 1, 2, and 8 weeks. Urinary cGMP was measured, and the levels and activity of NO synthase (NOS) isoforms in the kidney cortex were determined at specific times by immunoblotting and diaphorase staining. RESULTS Diabetic rats had increased kidney weight, urinary volume, glucose, sodium and potassium excretion, which was precluded by insulin treatment. Creatinine clearance was increased in the diabetic group and reversed by insulin treatment. Urinary cGMP decreased by 71, 93, and 92% at 1, 2, and 8 weeks of diabetes, respectively, compared with the control animals. Insulin treatment curtailed the urinary cGMP reduction in diabetic animals. Total NOS activity in the renal cortex was reduced by 65, 52, and 44% after 1, 2, and 8 weeks of diabetes, respectively, and returned to normal levels upon insulin treatment. NADPH diaphorase staining of renal cortical slices showed a 77, 63, and 70% decrease in neuronal NOS isoform activity in the macula densa after 1, 2, and 8 weeks of diabetes, respectively, compared with control non-diabetic animals. This reduction was normalized by insulin treatment. Endothelial NOS protein expression in the kidney cortex tended to increase after 1 week of diabetes and its level was elevated significantly after 2 and 8 weeks of diabetes. However, neuronal NOS protein expression in the kidney cortex was reduced by 52% in 2-week diabetic animals, but this reduction was normalized by insulin treatment. CONCLUSIONS The decreased renal NOS activity during the late phase of diabetes is partially associated with a decrease in neuronal NOS activity and protein expression in kidney macula densa.
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Affiliation(s)
- Mogher Khamaisi
- Department of Internal Medicine B, Diabetes Center, Hadassah University Hospital, Jerusalem, Israel.
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Gil FZ, Lucas SRR, Gomes GN, Cavanal MDF, Coimbra TM. Effects of intrauterine food restriction and long-term dietary supplementation with L-arginine on age-related changes in renal function and structure of rats. Pediatr Res 2005; 57:724-31. [PMID: 15774822 DOI: 10.1203/01.pdr.0000159514.06939.7e] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We have previously demonstrated that restricting intrauterine food by 50% in 3-mo-old rats produced lower nephron numbers and early-onset hypertension, the latter being normalized by L-arginine administration. In 18-mo-old rats, such restriction increased glomerulosclerosis. In this study, we expanded our investigation, evaluating functional, morphologic, and immunohistochemical parameters in intrauterine-food-restricted 18-mo-old rats, either receiving L-arginine (RA18) or not (R18). Age-matched, non-food-restricted controls were assigned to similar groups with L-arginine (CA18) and without (C18). After weaning, L-arginine was given daily for 17 mo. No functional or morphologic changes were observed in C18 rats. The R18 rats developed early-onset hypertension, which persisted throughout the observation period, as well as significant proteinuria from 12 mo on. In RA18 rats, L-arginine decreased both blood pressure levels and proteinuria, and glomerular diameter was significantly smaller than in R18 rats (115.63 +/- 2.2 versus 134.8 +/- 1.0 mum, p < 0.05). However, in RA18 rats, glomerular filtration rate remained depressed. Although L-arginine prevented glomerulosclerosis (R18 = 14%, RA18 = 4%; p < 0.05), glomerular expression of fibronectin and desmin was still greater in RA18 rats than in controls. Our data show that, although L-arginine prevented hypertension and proteinuria, glomerular injury still occurred, suggesting that intrauterine food restriction may be one of the leading causes of impaired renal function in adult life.
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Affiliation(s)
- Frida Zaladek Gil
- Department of Physiology, Renal Physiology, and Metabolic Biology, UNIFESP-EPM, São Paulo, Brazil, 04023-900.
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Komers R, Lindsley JN, Oyama TT, Anderson S. Effects of long-term inhibition of neuronal nitric oxide synthase (NOS1) in uninephrectomized diabetic rats. Nitric Oxide 2005; 11:147-55. [PMID: 15491847 DOI: 10.1016/j.niox.2004.08.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2003] [Revised: 07/22/2004] [Indexed: 11/29/2022]
Abstract
Nitric oxide (NO) has been implicated in the pathogenesis of renal hemodynamic changes in diabetes mellitus (DM). However, the role of NO in the pathophysiology of diabetic nephropathy remains controversial. Renal hemodynamic changes in experimental DM can be acutely normalized by selective inhibition of neuronal NO synthase (nNOS). This observation suggests a nephroprotective potential of nNOS inhibition in DM. To explore this issue we assessed the long-term effects (12 weeks) of selective nNOS inhibition with the specific inhibitor S-methyl-L-thiocitrulline (SMTC) in uninephrectomized control and streptozotocin-diabetic rats. No beneficial effects of SMTC were observed in nondiabetic controls. In contrast, SMTC delayed the development of proteinuria (32+/-8 vs. 53+/-9 mg/24h, week 8, p < 0.05) and glomerulosclerosis (GS, 0.30+/-0.08 vs. 0.57+/-0.05, p < 0.05) in diabetic rats. These effects coincided with early effects of treatment on the glomerular filtration rate, and were associated with lower renal expression of nNOS. Furthermore, SMTC-treated diabetic rats demonstrated reduced weight gain and urinary sodium excretion as compared to vehicle-treated counterparts, despite similar metabolic control and blood pressure. In summary, long-term nNOS inhibition had modest nephroprotective effects in uninephrectomized diabetic rats. These effects may be mediated by renal hemodynamic mechanisms, as well as by lower food (protein) intake.
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Affiliation(s)
- Radko Komers
- Division of Nephrology and Hypertension, Oregon Health and Science University, PP262, 3314 SW US Veterans Hospital Road, Portland, OR 97239-2940, USA
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Casey RG, Joyce M, Roche-Nagle G, Chen G, Bouchier-Hayes D. Pravastatin modulates early diabetic nephropathy in an experimental model of diabetic renal disease. J Surg Res 2005; 123:176-81. [PMID: 15680375 DOI: 10.1016/j.jss.2004.08.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2004] [Indexed: 11/18/2022]
Abstract
BACKGROUND Development of diabetes causes early functional (endothelial dysfunction) and morphological abnormalities in the kidney. If left untreated, these will ultimately progress to renal failure. Apart from strategies aimed at maintaining very tight glycemic control, attention has turned to the development of adjuvant therapy to maintain endothelial function in these patients. The agents receiving the most critical appraisal due to their endothelial protective effects are the 3-hydrox 3-methylglutaryl (HMG)-Co-enzyme A (CoA) reductase inhibitors. The aim of the study was to investigate: (1) the early alterations in the renal diabetic injury; and (2) to examine the protective role of Pravastatin in this end-organ diabetic model. MATERIALS AND METHODS Sprague Dawley rats (n = 21) were randomized into three groups: (1) control; (2) diabetic; and (3) diabetic treated with Pravastatin. Diabetic nephropathy was investigated with serum biochemical parameters (urea, creatinine), functional parameters (total urinary protein loss, glomerular filtration rate, renal cortical blood flow), and structural assessment (hemotoxylin and eosin staining). RESULTS We demonstrated impairment in functional, biochemical, and structural parameters in the diabetic nephropathy group, which was diminished by treatment with Pravastatin. This was attributed to an up-regulation in endothelial constitutive nitric oxide synthase (ecNOS) expression in the treated diabetic group. CONCLUSIONS We have shown that Pravastatin, in an experimental model of early diabetes nephropathy preserves microvascular endothelial function in the presence of hyperglycemia, thus inhibiting the early stage of diabetic microangiopathy.
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Affiliation(s)
- R G Casey
- Department of Surgical Research, Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin, Ireland.
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Wang Y, Nagase S, Koyama A. Stimulatory effect of IGF-I and VEGF on eNOS message, protein expression, eNOS phosphorylation and nitric oxide production in rat glomeruli, and the involvement of PI3-K signaling pathway. Nitric Oxide 2005; 10:25-35. [PMID: 15050532 DOI: 10.1016/j.niox.2004.02.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2003] [Revised: 01/26/2004] [Indexed: 11/20/2022]
Abstract
Nitric oxide (NO) is reported to be involved in the pathogenesis of renal hyperfiltration in the early stage of diabetic nephropathy. We set out to determine whether IGF-I and/or VEGF165 directly stimulate NO production in rat glomeruli and whether the expression of NO synthase (NOS) isoforms as well as eNOS phosphorylation contribute to NO generation by IGF-I and VEGF. Long-term exposure to IGF-I and/or VEGF165 augments NO production through increased eNOS mRNA, protein expression and phosphatidylinositol 3-kinase (PI3-K) signaling pathway plays a major role in this process; short-term exposure to IGF-I and/or VEGF(165) activates eNOS activity via phosphorylation by a PI3-K/Akt dependent pathway. Our data suggest the great possibility that increased endogenous IGF-I and VEGF may be responsible for the up-regulation of eNOS expression and NO production which contributes to glomerular hyperfiltration in early diabetic kidneys. IGF-I is a newly described growth factor that up-regulates eNOS expression and PI3-K plays a major role in this process.
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Affiliation(s)
- Ying Wang
- Department of Internal Medicine, Institute of Clinical Medicine, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
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Vonend O, Turner CM, Chan CM, Loesch A, Dell'Anna GC, Srai KS, Burnstock G, Unwin RJ. Glomerular expression of the ATP-sensitive P2X receptor in diabetic and hypertensive rat models. Kidney Int 2005; 66:157-66. [PMID: 15200422 DOI: 10.1111/j.1523-1755.2004.00717.x] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND The molecular identification and characterization of the adenosine triphosphate (ATP)-sensitive family of P2 receptors is comparatively new. There are two main subgroups, each with several subtypes and widespread tissue distribution, including the kidney. A unique member of the P2X subgroup of P2 receptors is the ATP-gated ion channel P2X(7), which on activation can cause cell blebbing, cytokine release, and cell death by necrosis or apoptosis. We report expression of this receptor in normal rat kidney and in two chronic models of glomerular injury: streptozotocin-induced (STZ) diabetes and ren-2 transgenic (TGR) hypertension. METHODS At different time points in these models, we used a polyclonal antibody to the P2X(7) receptor and immunohistochemistry to determine its expression and distribution. We also used Western blotting and real-time polymerase chain reaction (PCR) to detect changes in P2X(7) receptor protein and mRNA expression, respectively. RESULTS We found only low-level glomerular immuno-staining for the P2X(7) receptor in normal rat kidney, but intense P2X(7) receptor immunostaining of glomeruli in kidneys from diabetic animals at 6 and 9 weeks, and in hypertensive animals at 12 weeks. In diabetic animals, real-time PCR demonstrated a approximately tenfold increase in glomerular P2X(7) receptor mRNA relative to control, and Western blotting confirmed an increase in protein. Immunohistochemistry and immunoelectron microscopy showed staining of glomerular podocytes, which was both intracellular and at the plasma membrane. CONCLUSION We conclude that the P2X(7) receptor is not expressed appreciably under normal conditions, but that following glomerular injury it is significantly up-regulated, mainly in podocytes, though also in endothelial and mesangial cells, of animals with STZ-induced diabetes mellitus or TGR hypertension. Although the exact function and regulation of this receptor remain unclear, its association with inflammatory cytokine release and cell death suggests that increased expression might be involved in the pathogenesis of glomerular cell injury or repair.
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Affiliation(s)
- Oliver Vonend
- Centre for Nephrology and Department of Physiology, Royal Free and University College Medical School, University College London, London, United Kingdom
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Schrijvers BF, De Vriese AS, Flyvbjerg A. From hyperglycemia to diabetic kidney disease: the role of metabolic, hemodynamic, intracellular factors and growth factors/cytokines. Endocr Rev 2004; 25:971-1010. [PMID: 15583025 DOI: 10.1210/er.2003-0018] [Citation(s) in RCA: 242] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
At present, diabetic kidney disease affects about 15-25% of type 1 and 30-40% of type 2 diabetic patients. Several decades of extensive research has elucidated various pathways to be implicated in the development of diabetic kidney disease. This review focuses on the metabolic factors beyond blood glucose that are involved in the pathogenesis of diabetic kidney disease, i.e., advanced glycation end-products and the aldose reductase system. Furthermore, the contribution of hemodynamic factors, the renin-angiotensin system, the endothelin system, and the nitric oxide system, as well as the prominent role of the intracellular signaling molecule protein kinase C are discussed. Finally, the respective roles of TGF-beta, GH and IGFs, vascular endothelial growth factor, and platelet-derived growth factor are covered. The complex interplay between these different pathways will be highlighted. A brief introduction to each system and description of its expression in the normal kidney is followed by in vitro, experimental, and clinical evidence addressing the role of the system in diabetic kidney disease. Finally, well-known and potential therapeutic strategies targeting each system are discussed, ending with an overall conclusion.
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Affiliation(s)
- Bieke F Schrijvers
- Medical Department M/Medical Research Laboratories, Clinical Institute, Aarhus University Hospital, Nørrebrogade 44, DK-8000 Aarhus C, Denmark
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Abstract
Diabetic nephropathy is the leading cause of end-stage renal disease in the Western hemisphere. Endothelial dysfunction is the central pathophysiologic denominator for all cardiovascular complications of diabetes including nephropathy. Abnormalities of nitric oxide (NO) production modulate renal structure and function in diabetes but, despite the vast literature, major gaps exist in our understanding in this field because the published studies mostly are confusing and contradictory. In this review, we attempt to review the existing literature, discuss the controversies, and reach some general conclusions as to the role of NO production in the diabetic kidney. The complex metabolic milieu in diabetes triggers several pathophysiologic mechanisms that simultaneously stimulate and suppress NO production. The net effect on renal NO production depends on the mechanisms that prevail in a given stage of the disease. Based on the current evidence, it is reasonable to conclude that early nephropathy in diabetes is associated with increased intrarenal NO production mediated primarily by constitutively released NO (endothelial nitric oxide synthase [eNOS] and neuronal nitric oxide synthase [nNOS]). The enhanced NO production may contribute to hyperfiltration and microalbuminuria that characterizes early diabetic nephropathy. On the other hand, a majority of the studies indicate that advanced nephropathy leading to severe proteinuria, declining renal function, and hypertension is associated with a state of progressive NO deficiency. Several factors including hyperglycemia, advanced glycosylation end products, increased oxidant stress, as well as activation of protein kinase C and transforming growth factor (TGF)-beta contribute to decreased NO production and/or availability. These effects are mediated through multiple mechanisms such as glucose quenching, and inhibition and/or posttranslational modification of NOS activity of both endothelial and inducible isoforms. Finally, genetic polymorphisms of the NOS enzyme also may play a role in the NO abnormalities that contribute to the development and progression of diabetic nephropathy.
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Affiliation(s)
- Sharma S Prabhakar
- Department of Internal Medicine-Nephrology, Texas Tech University Health Sciences Center, Lubbock 79430, USA.
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36
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Abstract
Cellular injury or organ dysfunction from oxidative stress occurs when reactive oxygen species (ROS) accumulate in excess of the host defense mechanisms. The deleterious effect of ROS occurs from 2 principal actions. First, ROS can inactivate mitochondrial enzymes, damage DNA, or lead to apoptosis or cellular hypertrophy. Second, nitric oxide (NO), which is a principal endothelial-derived relaxing factor, reacts with superoxide anion (O2-) to yield peroxynitrite (ONOO-), which is a powerful oxidant and nitrosating agent. The inactivation of NO by O2- creates NO deficiency. Oxidative stress can promote the production of vasoconstrictor molecules and primary salt retention by the kidney. Several hypertensive animal models showed increased activity of nicotine adenine dinucleotide phosphate (NADPH) oxidase, which is the chief source of O2- in the vessel wall and kidneys. NO regulates renal blood flow, tubuloglomerular feedback (TGF), and pressure natriuresis. Animal models of NO deficiency develop hypertension, proteinuria, and glomerulosclerosis. Evidence is presented that chronic renal failure (CRF) is a state of NO deficiency secondary to decreased kidney NO production and/or increased bioinactivation of NO by O2-. Patients with CRF show decreased endothelium-dependent vasodilatation to acetylcholine, have increased markers of oxidative stress, and diminished antioxidant activity. Therapy for oxidative stress has focused on antioxidants and agents that modify the renin-angiotensin system. The effects of such treatments are more compelling in animal models than in human studies.
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Affiliation(s)
- Paul S Modlinger
- Division of Nephrology and Hypertension, Georgetown University Medical Center, Washington, DC 20007, USA
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37
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Schwartz IF, Iaina A, Benedict Y, Wollman Y, Chernichovski T, Brasowski E, Misonzhnik F, Ben-Dor A, Blum M, Levo Y, Schwartz D. Augmented arginine uptake, through modulation of cationic amino acid transporter-1, increases GFR in diabetic rats. Kidney Int 2004; 65:1311-9. [PMID: 15086470 DOI: 10.1111/j.1523-1755.2004.00508.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND It is suggested that either arginine or its metabolites, nitric oxide and polyamines play a role in the renal hemodynamic alterations observed in the early stages of diabetes. Yet, the regulation of arginine transport in diabetic kidneys has never been studied. METHODS Arginine uptake was determined in glomeruli harvested from control rats; diabetic rats (2 weeks following an intraperitoneal injection of streptozotocin, 60 mg/kg body weight); rats, 4 days following left nephrectomy (a nondiabetic model of hyperfiltration); diabetes + lysine (0.5% in the drinking water to attenuate arginine uptake); and control + lysine. RESULTS Glomerular arginine transport was significantly increased in diabetic rats, but remained unchanged following uninephrectomy. Lysine abolished the increase in arginine uptake in diabetic rats but had no effect in controls. The increase in creatinine clearance observed in diabetes was completely abolished by lysine. Using reverse transcription-polymerase chain reaction (RT-PCR), Northern blotting, and immunohistochemistry, we found a significant increase in glomerular cationic amino acid transporter-1 (CAT-1) expression in diabetic animals, which was unaffected by lysine. When human endothelial cells were incubated with arginine end products no effect on arginine transport was observed. However, only in the presence of 0.5 mM/L sodium nitroprusside (SNP) an augmented steady-state CAT-1 mRNA was demonstrated by RT-PCR. CONCLUSION In a rat model of early diabetes, glomerular arginine uptake is elevated through modulation of CAT-1 expression, thus, contributing to the pathogenesis of hyperfiltration. Increased nitric oxide formation may play a role in this process.
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Affiliation(s)
- Idit F Schwartz
- Nephrology Department, Tel Aviv Sourasky Medical Center, Tel Aviv University, Sackler School of Medicine, Tel Aviv, Israel.
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Cherla G, Jaimes EA. Role of L-arginine in the pathogenesis and treatment of renal disease. J Nutr 2004; 134:2801S-2806S; discussion 2818S-2819S. [PMID: 15465789 DOI: 10.1093/jn/134.10.2801s] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
L-arginine is a semi essential amino acid and also a substrate for the synthesis of nitric oxide (NO), polyamines, and agmatine. These L-arginine metabolites may participate in the pathogenesis of renal disease and constitute the rationale for manipulating L-arginine metabolism as a strategy to ameliorate kidney disease. Modification of dietary L-arginine intake in experimental models of kidney diseases has been shown to have both beneficial as well as deleterious effects depending on the specific model studied. L-arginine supplementation in animal models of glomerulonephritis has been shown to be detrimental, probably by increasing the production of NO from increased local expression of inducible NO synthase (iNOS). L-arginine supplementation does not modify the course of renal disease in humans with chronic glomerular diseases. However, beneficial effects of L-arginine supplementation have been reported in several models of chronic kidney disease including renal ablation, ureteral obstruction, nephropathy secondary to diabetes, and salt-sensitive hypertension. L-arginine is reduced in preeclampsia and recent experimental studies indicate that L-arginine supplementation may be beneficial in attenuating the symptoms of preeclampsia. Administration of exogenous L-arginine has been shown to be protective in ischemic acute renal failure. In summary, the role of L-arginine in the pathogenesis and treatment of renal disease is not completely understood and remains to be established.
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Affiliation(s)
- Gautam Cherla
- Nephrology Section VA Medical Center, Renal Division, Miami, FL 33136, USA
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Guarnieri G, Biolo G, Zanetti M, Barazzoni R. Chronic systemic inflammation in uremia: Potential therapeutic approaches. Semin Nephrol 2004; 24:441-5. [PMID: 15490407 DOI: 10.1016/j.semnephrol.2004.06.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Systemic inflammation characterizes several chronic diseases including uremia. Inflammation may contribute to morbidity and mortality by enhancing protein-calorie malnutrition, infectious complications, and atherosclerosis and cardiovascular disease. Although inflammation in renal disease can be caused, at least in part, by reduced renal clearance of proinflammatory mediators (tumor necrosis factor [TNF]-alpha, interleukin [IL]-6), several pathogenetic mechanisms are likely to contribute to direct activation of the inflammatory process under these conditions. These mechanisms include accumulation of advance glycoxidation end products, production of reactive oxygen species and oxidative damage, and chronic infection. Support for direct activation of systemic inflammation provides a strong rationale for use of anti-inflammatory treatments in uremia. The current article describes the association between uremia and inflammation, provides evidence for activation of inflammatory process, and provides potential therapeutic approaches.
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Affiliation(s)
- Gianfranco Guarnieri
- Clinica Medica, Department of Clinical, Morphological and Technological Services, University of Trieste, Trieste, Italy.
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40
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Abstract
Infusion of L-arginine in experimental animals increases renal plasma flow (RPF) and glomerular filtration rate (GFR). It is likely that a component of these hemodynamic changes are mediated by nitric oxide (NO) as suggested by studies with specific antagonists of L-arginine metabolism. L-arginine administration ameliorates the infiltration of the renal parenchyma by macrophages in rats with obstructive nephropathy or rats with puromycin-induced nephrotic syndrome. L-arginine administration also blunts the increase in interstitial volume, collagen IV, and alpha-smooth muscle actin. Rats with a remnant kidney given 1% L-arginine in the drinking water had a greater GFR and RPF. L-arginine administration also decreased proteinuria. Diabetic rats given L-arginine had significantly lower excretion of protein and cyclic guanosine monophosphate than diabetic rats not receiving L-arginine. Despite persistent hyperglycemia, the administration of L-arginine prevented the development of hyperfiltration and ameliorated proteinuria in diabetic rats. In the setting of ischemic acute renal failure, the administration of L-arginine had a beneficial effect on GFR and RPF, decreased O2- production, diminished up-regulation of soluble guanylate cyclase, and prevented up-regulation of inducible NO synthase (iNOS). The pharmacokinetics of L-arginine indicate that side effects are rare and mostly mild and dose dependent.
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Affiliation(s)
- Saulo Klahr
- Department of Internal Medicine, Washington University School of Medicine, St Louis, MO 63110-1092, USA.
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41
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Abstract
The tubuloglomerular feedback response, the change in afferent arteriolar tone caused by a change in NaCl concentration at the macula densa, is likely initiated by the generation of a vasoactive mediator within the confines of the juxtaglomerular apparatus. Substantial progress has been made in identifying the nature of this mediator and the factors that modulate its effect on vascular tone. In support of earlier studies using P1 purinergic antagonists, the application of the knockout technique has shown that adenosine 1 receptors are absolutely required for eliciting TGF responses. The background level of angiotensin II appears to be an important cofactor determining the efficiency of A1AR-induced vasoconstriction, probably through a synergistic interaction at the level of the G protein-dependent transduction mechanism. The source of the adenosine is still unclear, but it is conceivable that adenosine is generated extracellularly from released ATP through a cascade of ecto-nucleotidases. There is also evidence that ATP may activate P2 receptors in preglomerular vessels, which may contribute to autoregulation of renal vascular resistance. Nitric oxide (NO), generated by the neuronal isoform of nitric oxide synthase in macula densa cells, reduces the constrictor effect of adenosine, but the regulation of NO release and its exact role in states of TGF-induced hyperfiltration are still unclear.
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Affiliation(s)
- Jürgen Schnermann
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-1370, USA.
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42
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Abstract
As an important modulator of renal function and morphology, the nitric oxide (NO) system has been extensively studied in the diabetic kidney. However, a number of studies in different experimental and clinical settings have produced often confusing data and contradictory findings. We have reviewed a wide spectrum of findings and issues that have amassed concerning the pathophysiology of the renal NO system in diabetes, pointed out the controversies, and attempted to find some explanation for these discrepancies. Severe diabetes with profound insulinopenia can be viewed as a state of generalized NO deficiency, including in the kidney. However, we have focused our hypotheses and conclusions on the events occurring during moderate glycemic control with some degree of treatment with exogenous insulin, representing more the clinically applicable state of diabetic nephropathy. Available evidence suggests that diabetes triggers mechanisms that in parallel enhance and suppress NO bioavailability in the kidney. We hypothesize that during the early phases of nephropathy, the balance between these two opposing forces is shifted toward NO. This plays a role in the development of characteristic hemodynamic changes and may contribute to consequent structural alterations in glomeruli. Both endothelial (eNOS) and neuronal NO synthase can contribute to altered NO production. These enzymes, particularly eNOS, can be activated by Ca(2+)-independent and alternative routes of activation that may be elusive in traditional methods of investigation. As the duration of exposure to the diabetic milieu increases, factors that suppress NO bioavailability gradually prevail. Increasing accumulations of advanced glycation end products may be one of the culprits in this process. In addition, this balance is continuously modified by actual metabolic control and the degree of insulinopenia.
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Affiliation(s)
- Radko Komers
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon 97201-2940, USA
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43
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Sabbatini M, Pisani A, Uccello F, Fuiano G, Alfieri R, Cesaro A, Cianciaruso B, Andreucci VE. Arginase inhibition slows the progression of renal failure in rats with renal ablation. Am J Physiol Renal Physiol 2003; 284:F680-7. [PMID: 12475746 DOI: 10.1152/ajprenal.00270.2002] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Exogenous arginine slows the progression of chronic renal failure (CRF) in remnant rats through a nitric oxide (NO)-dependent mechanism. We tested whether the inhibition of arginase could induce similar results through the increased availability of endogenous arginine. Three groups of remnant rats were studied for 8 wk: 1) untreated rats (REM); 2) remnant rats treated with 1% l-arginine (ARG); and 3) remnant rats administered a Mn(2+)-free diet to inhibit arginase (MNF). Normal rats (NOR) were used as controls. Liver arginase activity was depressed in MNF rats (-35% vs. REM, P < 0.01). No difference in metabolic data was detected among the groups throughout the study; blood pressure was significantly lower in MNF vs. ARG and REM rats after 6 wk (P < 0.001). The glomerular filtration rate (GFR) was greatly depressed in REM rats (-47% vs. NOR, P < 0.03) but was higher in ARG and MNF rats (+40 and +43% vs. REM, respectively, P < 0.05), with comparable changes in renal hemodynamics. Despite the better GFR, proteinuria was decreased in both ARG and MNF rats (-42%, P < 0.05, and -57%, P < 0.01, respectively, vs. REM rats). Arginine plasma levels, significantly reduced in REM rats (-41% vs. NOR, P < 0.01), were partially restored in MNF rats (+38% vs. REM), and urinary nitrite excretion, greatly depressed in REM rats (-76% vs. NOR, P < 0.01), was significantly increased in MNF rats (+209% vs. REM, P < 0.05). At the renal level, arginase activity was only slightly depressed in MNF rats (-18% vs. REM), but intrarenal concentrations of arginine were lower in this latter group (P < 0.05 vs. other groups). Beyond the hemodynamic modifications, MNF rats showed a lower glomerular sclerosis index (P < 0.05 vs. REM and ARG). Inhibition of arginase slows the progression of CRF in remnant rats similarly to arginine-treated rats; the better histological protection in MNF rats, however, suggests that additional factors are involved in these modifications.
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Affiliation(s)
- Massimo Sabbatini
- Departments of Nephrology and Experimental Medicine, University Federico II, 80131 Naples, Italy.
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44
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Shimizu T, Onuma T, Kawamori R, Makita Y, Tomino Y. Endothelial nitric oxide synthase gene and the development of diabetic nephropathy. Diabetes Res Clin Pract 2002; 58:179-85. [PMID: 12413777 DOI: 10.1016/s0168-8227(02)00156-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
BACKGROUND Endothelial nitric oxide synthase gene and the development of diabetic nephropathy BACKGROUND Intron 4 insertion/deletion polymorphism of the constitutive endothelial nitric oxide synthase (ecNOS) gene may be related to diabetic nephropathy. METHODS A case-control study was performed in three groups of Japanese patients with Type 2 diabetes mellitus, which including 123 patients with advanced diabetic nephropathy, 107 patients with overt proteinuria and normal serum creatinine level, and a control group of 203 patients with normal renal function despite having diabetes for over 10 years. Additionally, logistic regression analysis was used to assess the findings. RESULTS When we examined the a-deletion/b-insertion in intron 4 of ecNOS gene, the genotype and allele frequencies were not significantly different between the patients with advanced diabetic nephropathy (a/a 2.4, a/b 21.9, b/b 75.5, 'a' 13.4, 'b' 86.6%), the patients with overt proteinuria (a/a 2.8, a/b 15.8, b/b 81.4, 'a' 10.7, 'b' 89.3%) and the control group (a/a 1.4, a/b 21.6, b/b 76.8, 'a' 12.8, 'b' 87.7%). Logistic regression analysis showed that the ecNOS intron4 a-allele frequency was not the related to nephropathy (P = 0.88). CONCLUSION We conclude that there is no association of the ecNOS gene polymorphism with the development of diabetic nephropathy in Japanese patients with type 2 diabetes.
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Affiliation(s)
- Tomoaki Shimizu
- Department of Medicine, Metabolism and Endocrinology, Juntendo University School of Medicine, Hongo 3-1-1, Bunkyo, Zip# 113-8421 Tokyo, Japan
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van Dam B, Demirci C, Reitsma HJ, van Lambalgen AA, van den Bos GC, Tangelder GJ, Stehouwer CDA. Arteriolar changes in nitric oxide activity and sensitivity during the course of streptozotocin-induced diabetes. Eur J Pharmacol 2002; 455:43-51. [PMID: 12433593 DOI: 10.1016/s0014-2999(02)02501-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Nitric oxide (NO) may play an important role in the pathogenesis of diabetic microangiopathy. However, arteriolar changes in NO activity and sensitivity to NO may be dependent on both the type of arteriole and the duration of diabetes. Therefore, we assessed, in the in situ spinotrapezius muscle preparation of streptozotocin-diabetic rats and of controls, inside diameters of A2-A4 arterioles and the reactivity to topically applied acetylcholine and nitroprusside, before and after N(G)-nitro-L-arginine (L-NNA) at 2, 4, 6 and 12 weeks of diabetes. In A2 arterioles, basal diameters and the contribution of NO to basal diameter were not affected during the course of streptozotocin-induced diabetes. However, the maximal response to acetylcholine in these arterioles was attenuated after 2 until 4 weeks, and from 4 weeks on a sustained decrease in reactivity to sodium nitroprusside was observed. In A3 arterioles, both the basal diameter and the contribution of NO to basal diameter were decreased after 2 weeks and increased after 6 weeks, while the response to sodium nitroprusside was unaffected. In A4 arterioles, a significant increase in basal diameter was observed after 6 weeks only. Thus, this study shows that streptozotocin-induced diabetes causes microvascular changes in NO activity and sensitivity that depend on the type of arteriole. For each order of arteriole, these changes show a specific pattern during the course of diabetes.
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Affiliation(s)
- Bastiaan van Dam
- Department of Internal Medicine, Institute for Cardiovascular Research, Vrije Universiteit, P.O. Box 7057, De Boelelaan, 1117, 1081 HV Amsterdam, The Netherlands
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Prabhakar SS. Tetrahydrobiopterin reverses the inhibition of nitric oxide by high glucose in cultured murine mesangial cells. Am J Physiol Renal Physiol 2001; 281:F179-88. [PMID: 11399659 DOI: 10.1152/ajprenal.2001.281.1.f179] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Alterations of intrarenal nitric oxide (NO) synthesis play an important role in the pathogenesis and progression of diabetic nephropathy. We tested the hypothesis that hyperglycemia modulates intrarenal NO synthesis, which might mediate the mesangial cell proliferation and matrix production. Murine mesangial cells were grown in media containing varying glucose concentrations, and cytokine-induced NO synthesis was assayed by chemiluminescence using an NO analyzer. High media glucose (25 mM) inhibited NO synthesis in a time-dependent fashion. This inhibition was posttranslational as revealed by analysis of inducible nitric oxide synthase (iNOS) gene and protein expression. L-Arginine supplementation partially reversed the inhibition whereas addition of tetrahydrobiopterin (BH4), a cofactor for NOS, restored the inducibility of NO synthesis. The in vitro [3H]citrulline assay for iNOS activity indicated that high glucose decreased BH4 availability whereas examination of the BH4 synthetic pathway suggested decreased BH4 stability rather than synthesis, a defect that was corrected by ascorbic acid. We conclude that hyperglycemia inhibits NO synthesis in mesangial cells by a posttranslational defect that might involve the stability and hence availability of BH4.
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Affiliation(s)
- S S Prabhakar
- Division of Nephrology, Department of Internal Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas 79430, USA.
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47
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Abstract
Vasoactive autocoids with directly opposing actions on the renal vasculature, glomerular function, and in salt and water homeostasis have been demonstrated in the kidney. In the renal cortex, endothelin (ET)-1 and angiotensin-II cause vasoconstriction, decreasing renal blood flow, and glomerular filtration rate, whereas bradykinin and atrial natriuretic peptide cause vasodilation and increase glomerular capillary permeability. ET-1 causes vasoconstriction of the afferent and efferent arteries and outer medullary descending vasa recta, thereby decreasing vasa recta and papillary blood flow, while bradykinin has the opposite effect. ET-1 stimulates cell proliferation, increasing the expression of several genes, including collagenase, prostaglandin endoperoxidase synthase, and platelet-derived growth factor. ET-1 promotes natriuresis via the ET-B receptor, causing down-regulation of the epithelial Na(+) channel in the renal tubule. Thus, ETs affect three major aspects of renal physiology: vascular and mesangial tone, Na(+) and water excretion, and cell proliferation and matrix formation.
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Affiliation(s)
- S Naicker
- Department of Medicine, Nelson R. Mandela School of Medicine, University of Natal, Durban, South Africa
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48
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Hochberg D, Johnson CW, Chen J, Cohen D, Stern J, Vaughan ED, Poppas D, Felsen D. Interstitial fibrosis of unilateral ureteral obstruction is exacerbated in kidneys of mice lacking the gene for inducible nitric oxide synthase. J Transl Med 2000; 80:1721-8. [PMID: 11092532 DOI: 10.1038/labinvest.3780182] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Unilateral ureteral obstruction (UUO) is characterized by decreases in renal function and increases in interstitial fibrosis. Previous studies have indicated that pharmacologic manipulations that increase nitric oxide (NO) are beneficial to the obstructed kidneys. NO is produced from arginine by nitric oxide synthase (NOS), an enzyme that exists in both constitutive and inducible (iNOS) forms. To determine the role of the inducible form of NOS in UUO, we used mice with a targeted deletion of iNOS (iNOS -/- mice) and compared them with wild-type (WT) mice. Kidneys were obstructed for 2 weeks in both WT and iNOS -/- mice, and were then removed and bisected. Half of the kidney was embedded in paraffin and tissue sections were examined for interstitial volume or the presence of macrophages. The remainder was flash-frozen and samples were used to measure tissue collagen (hydroxyproline) or transforming growth factor-beta (TGF-beta). This study demonstrates that both cortex and medulla of obstructed kidneys of iNOS -/- mice exhibit significantly increased interstitial volume and interstitial macrophages as compared with their WT counterparts. Furthermore tissue collagen was increased to 9.2+/-1.3 microg/mg tissue in WT obstructed kidneys, whereas in iNOS -/- kidneys, collagen was increased to 13.2+/-0.8 microg/mg tissue. The profibrotic cytokine TGF-beta was also significantly increased in obstructed kidneys of iNOS -/- mice, as compared with WT mice. No differences were noted between the unobstructed kidneys of iNOS -/- mice compared with WT mice in any of the parameters examined. These results demonstrate that targeted deletion of the iNOS results in exacerbation of fibrotic events in the obstructed kidney. These results confirm previous pharmacologic studies, and suggest that NO produced via the inducible NOS normally serves a protective function in UUO.
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Affiliation(s)
- D Hochberg
- Center for Pediatric Urology, Department of Urology, Children's Hospital of New York, Weill Medical College of Cornell University, New York 10021, USA
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49
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Komers R, Lindsley JN, Oyama TT, Allison KM, Anderson S. Role of neuronal nitric oxide synthase (NOS1) in the pathogenesis of renal hemodynamic changes in diabetes. Am J Physiol Renal Physiol 2000; 279:F573-83. [PMID: 10966937 DOI: 10.1152/ajprenal.2000.279.3.f573] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Nitric oxide (NO) has been implicated in the pathogenesis of renal hemodynamic changes in diabetes mellitus. However, the contribution of nitric oxide synthase (NOS) isoforms to intrarenal production of NO in diabetes remains unknown. To explore the role of NOS1 in the control of renal hemodynamics in diabetes, we assessed renal responses to inhibition of NOS1 with S-methyl-L-thiocitrulline (SMTC; administered into the abdominal aorta) in moderately hyperglycemic streptozotocin-diabetic rats (D) and their nondiabetic (C) and normoglycemic diabetic counterparts. The contribution of other NOS isoforms was also evaluated by assessing the responses to nonspecific NOS inhibition [N(G)-nitro-L-arginine methyl ester (L-NAME)] in SMTC-treated diabetic rats. The number of NOS1-positive cells in macula densa of D and C kidneys was also evaluated by immunohistochemistry. D rats demonstrated elevated glomerular filtration rate (GFR) compared with C. SMTC (0.05 mg/kg) normalized GFR in D but had no effect in C. SMTC-induced reduction of renal plasma flow (RPF) was similar in C and D. Normoglycemic diabetic rats demonstrated blunted renal hemodynamic responses to NOS1 inhibition compared with hyperglycemic animals. Mean arterial pressure was stable in all groups. L-NAME induced a further decrease in RPF, but not in GFR, in D rats treated with SMTC. Immunohistochemistry revealed increased numbers of NOS1-positive cells in D. These observations suggest that NOS1-derived NO plays a major role in the pathogenesis of renal hemodynamic changes early in the course of diabetes. NOS1 appears to be the most important isoform in the generation of hemodynamically active NO in this condition.
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Affiliation(s)
- R Komers
- Division of Nephrology and Hypertension, Oregon Health Sciences University, and Portland Veterans Affairs Medical Center, Portland, Oregon 97201, USA
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50
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Shihab FS, Yi H, Bennett WM, Andoh TF. Effect of nitric oxide modulation on TGF-beta1 and matrix proteins in chronic cyclosporine nephrotoxicity. Kidney Int 2000; 58:1174-85. [PMID: 10972680 DOI: 10.1046/j.1523-1755.2000.00273.x] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Chronic cyclosporine (CsA) nephrotoxicity is characterized by interstitial fibrosis and afferent arteriolar hyalinosis. L-arginine (L-Arg), the substrate for nitric oxide (NO) synthase and N-nitro-L-arginine-methyl ester (L-NAME), the NO synthase inhibitor, were shown to modulate acute CsA nephrotoxicity. However, the mechanism of fibrosis in chronic CsA nephrotoxicity remains unclear. Thus, we examined the effect of NO modulation on fibrosis and the expression of transforming growth factor-beta1 (TGF-beta1) and matrix proteins in chronic CsA nephrotoxicity. METHODS Rats were administered CsA (7.5 mg/kg), CsA + L-Arg (1.7 g/kg), CsA + L-NAME (3.5 mg/kg), vehicle (VH), VH + L-Arg, and VH + L-NAME, and were sacrificed at 7 or 28 days. NO production, physiologic parameters, and histology were studied in addition to the mRNA expression of TGF-beta1, plasminogen activator inhibitor-1 (PAI-1) and the matrix proteins biglycan and collagens type I and IV by Northern and the protein expression of PAI-1 and fibronectin by enzyme-linked immunosorbent assay. RESULTS While L-NAME strikingly reduced NO biosynthesis and worsened the glomerular filtration rate and CsA-induced fibrosis, L-Arg had the opposite beneficial effect. In addition, the CsA-induced up-regulated expression of TGF-beta1, PAI-1, and the matrix proteins biglycan, fibronectin, and collagen I was significantly increased with L-NAME and strikingly improved with L-Arg. Collagen IV expression was not affected. Also, NO modulation did not affect VH-treated rats. CONCLUSIONS Chronic CsA nephrotoxicity can be aggravated by NO blockade and ameliorated by NO enhancement, suggesting that NO maintains a protective function. NO modulation was associated with a change in TGF-beta1 expression, which, in turn, was associated with alterations in matrix deposition and matrix degradation through its effect on PAI-1.
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Affiliation(s)
- F S Shihab
- Divisions of Nephrology, University of Utah Health Sciences Center, Salt Lake City, Utah, USA.
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