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Edwards A. Renal handling of albumin in rats with early stage diabetes: A theoretical analysis. J Physiol 2024. [PMID: 38857419 DOI: 10.1113/jp286245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Accepted: 05/20/2024] [Indexed: 06/12/2024] Open
Abstract
In early diabetic nephropathy (DN), recent studies have shown that albuminuria stems mostly from alterations in tubular function rather than from glomerular damage. Several factors in DN, including hyperfiltration, hypertrophy and reduced abundance of the albumin receptors megalin and cubilin, affect albumin endocytosis in the proximal tubule (PT). To assess their respective contribution, we developed a model of albumin handling in the rat PT that couples the transport of albumin to that of water and solutes. Our simulations suggest that, under basal conditions, ∼75% of albumin is retrieved in the S1 segment. The model predicts negligible uptake in S3, as observed experimentally. It also accurately predicts the impact of acute hyperglycaemia on urinary albumin excretion. Simulations reproduce observed increases in albumin excretion in early DN by considering the combined effects of increased glomerular filtration rate (GFR), osmotic diuresis, hypertrophy, and megalin and cubilin downregulation, without stipulating changes in glomerular permselectivity. The results indicate that in isolation, glucose-elicited osmotic diuresis and glucose transporter upregulation raise albumin excretion only slightly. Enlargement of PT diameter not only augments uptake via surface area expansion, but also reduces fluid velocity and thus shear stress-induced stimulation of endocytosis. Overall, our model predicts that downregulation of megalin and cubilin and hyperfiltration both contribute significantly to increasing albumin excretion in rats with early-stage diabetes. The results also suggest that acute sodium-glucose cotransporter 2 inhibition lowers albumin excretion only if GFR decreases sufficiently, and that angiotensin II receptor blockers mitigate urinary albumin loss in early DN in large part by upregulating albumin receptor abundance. KEY POINTS: The urinary excretion of albumin is increased in early diabetic nephropathy (DN). It is difficult to experimentally disentangle the multiple factors that affect the renal handling of albumin in DN. We developed a mathematical model of albumin transport in the rat proximal tubule (PT) to examine the impact of elevated plasma glucose, hyperfiltration, PT hypertrophy and reduced abundance of albumin receptors on albumin uptake and excretion in DN. Our model predicts that glucose-elicited osmotic diuresis per se raises albumin excretion only slightly. Conversely, increases in PT diameter and length favour reduced albumin excretion. Our results suggest that downregulation of the receptors megalin and cubilin in PT cells and hyperfiltration both contribute significantly to increasing albumin excretion in DN. The model helps to better understand the mechanisms underlying urinary loss of albumin in early-stage diabetes, and the impact of specific treatments thereupon.
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Affiliation(s)
- Aurélie Edwards
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
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Mohandes S, Doke T, Hu H, Mukhi D, Dhillon P, Susztak K. Molecular pathways that drive diabetic kidney disease. J Clin Invest 2023; 133:165654. [PMID: 36787250 PMCID: PMC9927939 DOI: 10.1172/jci165654] [Citation(s) in RCA: 69] [Impact Index Per Article: 69.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023] Open
Abstract
Kidney disease is a major driver of mortality among patients with diabetes and diabetic kidney disease (DKD) is responsible for close to half of all chronic kidney disease cases. DKD usually develops in a genetically susceptible individual as a result of poor metabolic (glycemic) control. Molecular and genetic studies indicate the key role of podocytes and endothelial cells in driving albuminuria and early kidney disease in diabetes. Proximal tubule changes show a strong association with the glomerular filtration rate. Hyperglycemia represents a key cellular stress in the kidney by altering cellular metabolism in endothelial cells and podocytes and by imposing an excess workload requiring energy and oxygen for proximal tubule cells. Changes in metabolism induce early adaptive cellular hypertrophy and reorganization of the actin cytoskeleton. Later, mitochondrial defects contribute to increased oxidative stress and activation of inflammatory pathways, causing progressive kidney function decline and fibrosis. Blockade of the renin-angiotensin system or the sodium-glucose cotransporter is associated with cellular protection and slowing kidney function decline. Newly identified molecular pathways could provide the basis for the development of much-needed novel therapeutics.
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Affiliation(s)
- Samer Mohandes
- Renal, Electrolyte, and Hypertension Division, Department of Medicine;,Institute for Diabetes, Obesity, and Metabolism;,Department of Genetics; and,Kidney Innovation Center; Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Tomohito Doke
- Renal, Electrolyte, and Hypertension Division, Department of Medicine;,Institute for Diabetes, Obesity, and Metabolism;,Department of Genetics; and,Kidney Innovation Center; Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Hailong Hu
- Renal, Electrolyte, and Hypertension Division, Department of Medicine;,Institute for Diabetes, Obesity, and Metabolism;,Department of Genetics; and,Kidney Innovation Center; Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Dhanunjay Mukhi
- Renal, Electrolyte, and Hypertension Division, Department of Medicine;,Institute for Diabetes, Obesity, and Metabolism;,Department of Genetics; and,Kidney Innovation Center; Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Poonam Dhillon
- Renal, Electrolyte, and Hypertension Division, Department of Medicine;,Institute for Diabetes, Obesity, and Metabolism;,Department of Genetics; and,Kidney Innovation Center; Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Katalin Susztak
- Renal, Electrolyte, and Hypertension Division, Department of Medicine;,Institute for Diabetes, Obesity, and Metabolism;,Department of Genetics; and,Kidney Innovation Center; Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Tawfik MK, Keshawy MM, Makary S. Blocking angiotensin 2 receptor attenuates diabetic nephropathy via mitigating ANGPTL2/TL4/NF-κB expression. Mol Biol Rep 2021; 48:6457-6470. [PMID: 34431038 DOI: 10.1007/s11033-021-06647-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 08/11/2021] [Indexed: 01/13/2023]
Abstract
BACKGROUND Diabetic nephropathy (DN) is a consequence of diabetes mellitus (DM) and is associated with early changes in renal angiotensin II (ANG II). These changes were evaluated using ANG II blocker valsartan early from week two of diabetes (experiment I, renoprotective) and late from week nine of diabetes (experiment II, renotherapeutic) to the end of both experiments at week twelve. METHODS AND RESULTS In both experiments, adult male Wister rats were divided into (i) vehicle group; (ii) valsartan received oral 30 mg/Kg/day; (iii) diabetic received single 50 mg/Kg intraperitoneal streptozotocin injection; (iv) renoprotection, diabetic rats received valsartan treated in experiments I and II. DM effects on urine albumin excretion, blood pressure, and renal ANG II were measured. Urinary nephrin, kidney injury molecule-1 (KIM-1), renal angiopoietin-like protein 2 (ANGPTL2), and toll-like receptor 4 (TLR 4) mRNA expression were tested. DM-initiated fibrotic markers integrin, α-smooth muscle actin expression, and collagen IV and apoptotic protein caspase 3 were tested. DM induced early changes starting from week four in the tested variables. At week twelve, in both experiments, valsartan intervention showed a significant reduction in ANG II, ANGPTL2, TLR 4 and integrin expression and improvement in albuminuria, blood pressure, urinary biomarkers, fibrotic and apoptotic markers. CONCLUSIONS Changes leading to DN starts early in the disease course and ANG II reduction decreased the expression of ANGPTL2 and integrin which preserve the glomerular barrier. Blocking ANG II was able to decrease TLR 4 and inflammatory cytokines leading to decreasing DN.
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Affiliation(s)
- Mona K Tawfik
- Department of Pharmacology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
| | - Mohammed M Keshawy
- Nephrology Division, Department of Internal Medicine, Faculty of Medicine, Suez Canal University, Ismailia, 41522, Egypt.
| | - Samy Makary
- Department of Physiology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
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Patinha D, Abreu C, Carvalho C, Cunha OM, Mota M, Afonso J, Sousa T, Albino-Teixeira A, Diniz C, Morato M. Adenosine A 2A and A 3 Receptors as Targets for the Treatment of Hypertensive-Diabetic Nephropathy. Biomedicines 2020; 8:biomedicines8110529. [PMID: 33238361 PMCID: PMC7700226 DOI: 10.3390/biomedicines8110529] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 11/11/2020] [Accepted: 11/17/2020] [Indexed: 12/14/2022] Open
Abstract
Diabetic nephropathy (DN) and hypertension are prime causes for end-stage renal disease (ESRD) that often coexist in patients, but are seldom studied in combination. Kidney adenosine levels are markedly increased in diabetes, and the expression and function of renal adenosine receptors are altered in experimental diabetes. The aim of this work is to explore the impact of endogenous and exogenous adenosine on the expression/distribution profile of its receptors along the nephron of hypertensive rats with experimentally-induced diabetes. Using spontaneously hypertensive (SHR) rats rendered diabetic with streptozotocin (STZ), we show that treatment of SHR-STZ rats with an agonist of adenosine receptors increases A2A immunoreactivity in superficial glomeruli (SG), proximal tubule (PCT), and distal tubule (DCT). Differently, treatment of SHR-STZ rats with a xanthinic antagonist of adenosine receptors decreases adenosine A3 immunoreactivity in SG, PCT, DCT, and collecting duct. There is no difference in the immunoreactivity against the adenosine A1 and A2B receptors between the experimental groups. The agonist of adenosine receptors ameliorates renal fibrosis, probably via A2A receptors, while the antagonist exacerbates it, most likely due to tonic activation of A3 receptors. The reduction in adenosine A3 immunoreactivity might be due to receptor downregulation in response to prolonged activation. Altogether, these results suggest an opposite regulation exerted by endogenous and exogenous adenosine upon the expression of its A2A and A3 receptors along the nephron of hypertensive diabetic rats, which has a functional impact and should be taken into account when considering novel therapeutic targets for hypertensive-diabetic nephropathy.
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Affiliation(s)
- Daniela Patinha
- Department of Biomedicine—Unit of Pharmacology and Therapeutics, Faculty of Medicine, University of Porto, 4200-450 Porto, Portugal; (D.P.); (J.A.); (T.S.); (A.A.-T.)
- The Institute of Biomedical and Clinical Science, Medical School, University of Exeter, EX4 4QJ Exeter, UK
| | - Carla Abreu
- LAQV@REQUIMTE, Laboratory of Pharmacology, Department of Drug Sciences, Faculty of Pharmacy, University of Porto, 4050-313 Porto, Portugal; (C.A.); (C.C.); (O.M.C.); (M.M.); (M.M.)
| | - Carla Carvalho
- LAQV@REQUIMTE, Laboratory of Pharmacology, Department of Drug Sciences, Faculty of Pharmacy, University of Porto, 4050-313 Porto, Portugal; (C.A.); (C.C.); (O.M.C.); (M.M.); (M.M.)
| | - Olga Mariana Cunha
- LAQV@REQUIMTE, Laboratory of Pharmacology, Department of Drug Sciences, Faculty of Pharmacy, University of Porto, 4050-313 Porto, Portugal; (C.A.); (C.C.); (O.M.C.); (M.M.); (M.M.)
| | - Mariana Mota
- LAQV@REQUIMTE, Laboratory of Pharmacology, Department of Drug Sciences, Faculty of Pharmacy, University of Porto, 4050-313 Porto, Portugal; (C.A.); (C.C.); (O.M.C.); (M.M.); (M.M.)
| | - Joana Afonso
- Department of Biomedicine—Unit of Pharmacology and Therapeutics, Faculty of Medicine, University of Porto, 4200-450 Porto, Portugal; (D.P.); (J.A.); (T.S.); (A.A.-T.)
- MedInUP—Center for Drug Discovery and Innovative Medicines, University of Porto, 4200-319 Porto, Portugal
| | - Teresa Sousa
- Department of Biomedicine—Unit of Pharmacology and Therapeutics, Faculty of Medicine, University of Porto, 4200-450 Porto, Portugal; (D.P.); (J.A.); (T.S.); (A.A.-T.)
- MedInUP—Center for Drug Discovery and Innovative Medicines, University of Porto, 4200-319 Porto, Portugal
| | - António Albino-Teixeira
- Department of Biomedicine—Unit of Pharmacology and Therapeutics, Faculty of Medicine, University of Porto, 4200-450 Porto, Portugal; (D.P.); (J.A.); (T.S.); (A.A.-T.)
- MedInUP—Center for Drug Discovery and Innovative Medicines, University of Porto, 4200-319 Porto, Portugal
| | - Carmen Diniz
- LAQV@REQUIMTE, Laboratory of Pharmacology, Department of Drug Sciences, Faculty of Pharmacy, University of Porto, 4050-313 Porto, Portugal; (C.A.); (C.C.); (O.M.C.); (M.M.); (M.M.)
- Correspondence:
| | - Manuela Morato
- LAQV@REQUIMTE, Laboratory of Pharmacology, Department of Drug Sciences, Faculty of Pharmacy, University of Porto, 4050-313 Porto, Portugal; (C.A.); (C.C.); (O.M.C.); (M.M.); (M.M.)
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Patinha D, Carvalho C, Persson P, Pihl L, Fasching A, Friederich-Persson M, O'Neill J, Palm F. Determinants of renal oxygen metabolism during low Na + diet: effect of angiotensin II AT 1 and aldosterone receptor blockade. J Physiol 2020; 598:5573-5587. [PMID: 32857872 DOI: 10.1113/jp280481] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 08/26/2020] [Indexed: 01/13/2023] Open
Abstract
KEY POINTS Reducing Na+ intake reduces the partial pressure of oxygen in the renal cortex and activates the renin-angiotensin-aldosterone system. In the absence of high blood pressure, these consequences of dietary Na+ reduction may be detrimental for the kidney. In a normotensive animal experimental model, reducing Na+ intake for 2 weeks increased renal oxygen consumption, which was normalized by mineralocorticoid receptor blockade. Furthermore, blockade of the angiotensin II AT1 receptor restored cortical partial pressure of oxygen by improving oxygen delivery. This shows that increased activity of the renin-angiotensin-aldosterone system contributes to increased oxygen metabolism in the kidney after 2 weeks of a low Na+ diet. The results provide insights into dietary Na+ restriction in the absence of high blood pressure, and its consequences for the kidney. ABSTRACT Reduced Na+ intake reduces the P O 2 (partial pressure of oxygen) in the renal cortex. Upon reduced Na+ intake, reabsorption along the nephron is adjusted with activation of the renin-angiotensin-aldosterone system (RAAS). Thus, we studied the effect of reduced Na+ intake on renal oxygen homeostasis and function in rats, and the impact of intrarenal angiotensin II AT1 receptor blockade using candesartan and mineralocorticoid receptor blockade using canrenoic acid potassium salt (CAP). Male Sprague-Dawley rats were fed standard rat chow containing normal (0.25%) and low (0.025%) Na+ for 2 weeks. The animals were anaesthetized (thiobutabarbital 120 mg kg-1 ) and surgically prepared for kidney oxygen metabolism and function studies before and after acute intrarenal arterial infusion of candesartan (4.2 μg kg-1 ) or intravenous infusion of CAP (20 mg kg-1 ). Baseline mean arterial pressure and renal blood flow were similar in both dietary groups. Fractional Na+ excretion and cortical oxygen tension were lower and renal oxygen consumption was higher in low Na+ groups. Neither candesartan nor CAP affected arterial pressure. Renal blood flow and cortical oxygen tension increased in both groups after candesartan in the low Na+ group. Fractional Na+ excretion was increased and oxygen consumption reduced in the low Na+ group after CAP. These results suggest that blockade of angiotensin II AT1 receptors has a major impact upon oxygen delivery during normal and low Na+ conditions, while aldosterone receptors mainly affect oxygen metabolism following 2 weeks of a low Na+ diet.
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Affiliation(s)
- Daniela Patinha
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, University of Exeter, Exeter, UK.,Department of Medical Cell Biology, Division of Integrative Physiology, Uppsala University, Uppsala, Sweden
| | - Carla Carvalho
- Department of Medical Cell Biology, Division of Integrative Physiology, Uppsala University, Uppsala, Sweden
| | - Patrik Persson
- Department of Medical Cell Biology, Division of Integrative Physiology, Uppsala University, Uppsala, Sweden
| | - Liselotte Pihl
- Department of Medical Cell Biology, Division of Integrative Physiology, Uppsala University, Uppsala, Sweden
| | - Angelica Fasching
- Department of Medical Cell Biology, Division of Integrative Physiology, Uppsala University, Uppsala, Sweden
| | - Malou Friederich-Persson
- Department of Medical Cell Biology, Division of Integrative Physiology, Uppsala University, Uppsala, Sweden
| | - Julie O'Neill
- Department of Medical Cell Biology, Division of Integrative Physiology, Uppsala University, Uppsala, Sweden
| | - Fredrik Palm
- Department of Medical Cell Biology, Division of Integrative Physiology, Uppsala University, Uppsala, Sweden
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Patinha D, Carvalho C, Abreu C, Cunha OM, Mota MC, Afonso J, Albino-Teixeira A, Diniz C, Morato M. Diabetes downregulates renal adenosine A2A receptors in an experimental model of hypertension. PLoS One 2019; 14:e0217552. [PMID: 31150459 PMCID: PMC6544351 DOI: 10.1371/journal.pone.0217552] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 05/14/2019] [Indexed: 12/18/2022] Open
Abstract
Studies on diabetic nephropathy rarely take into account that the co-existence of diabetes and hypertension is frequent and further aggravates the prognosis of renal dysfunction. Adenosine can activate four subtypes of adenosine receptors (A1, A2A, A2B and A3) and has been implicated in diabetic nephropathy. However, it is not known if, in hypertensive conditions, diabetes alters the presence/distribution profile of renal adenosine receptors. The aim of this work was to describe the presence/distribution profile of the four adenosine receptors in six renal structures (superficial/deep glomeruli, proximal/distal tubules, loop of Henle, collecting tubule) of the hypertensive kidney and to evaluate whether it is altered by diabetes. Immunoreactivities against the adenosine receptors were analyzed in six renal structures from spontaneously hypertensive rats (SHR, the control group) and from SHR rats with diabetes induced by streptozotocyin (SHR-STZ group). Data showed, for the first time, that all adenosine receptors were present in the kidney of SHR rats, although the distribution pattern was specific for each adenosine receptor subtype. Also, induction of diabetes in the SHR was associated with downregulation of adenosine A2A receptors, which might be relevant for the development of hypertensive diabetic nephropathy. This study highlights the adenosine A2A receptors as a potential target to explore to prevent and/or treat early diabetes-induced hyperfiltration, at least in hypertensive conditions.
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Affiliation(s)
- Daniela Patinha
- Pharmacology and Therapeutics Unit, Department of Biomedicine, Faculty of Medicine, University of Porto, Porto, Portugal
| | - Carla Carvalho
- LAQV@REQUIMTE, Laboratory of Pharmacology, Department of Drug Sciences, Faculty of Pharmacy, University of Porto, Porto, Portugal
| | - Carla Abreu
- LAQV@REQUIMTE, Laboratory of Pharmacology, Department of Drug Sciences, Faculty of Pharmacy, University of Porto, Porto, Portugal
| | - Olga M. Cunha
- LAQV@REQUIMTE, Laboratory of Pharmacology, Department of Drug Sciences, Faculty of Pharmacy, University of Porto, Porto, Portugal
| | - Mariana C. Mota
- LAQV@REQUIMTE, Laboratory of Pharmacology, Department of Drug Sciences, Faculty of Pharmacy, University of Porto, Porto, Portugal
| | - Joana Afonso
- Pharmacology and Therapeutics Unit, Department of Biomedicine, Faculty of Medicine, University of Porto, Porto, Portugal
- MedInUP–Center for Drug Discovery and Innovative Medicines, University of Porto, Porto, Portugal
| | - António Albino-Teixeira
- Pharmacology and Therapeutics Unit, Department of Biomedicine, Faculty of Medicine, University of Porto, Porto, Portugal
- MedInUP–Center for Drug Discovery and Innovative Medicines, University of Porto, Porto, Portugal
| | - Carmen Diniz
- LAQV@REQUIMTE, Laboratory of Pharmacology, Department of Drug Sciences, Faculty of Pharmacy, University of Porto, Porto, Portugal
- * E-mail: (CD); (MM)
| | - Manuela Morato
- LAQV@REQUIMTE, Laboratory of Pharmacology, Department of Drug Sciences, Faculty of Pharmacy, University of Porto, Porto, Portugal
- * E-mail: (CD); (MM)
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Makary S, Abdo M, Hassan WA, Tawfik MK. Angiotensin blockade attenuates diabetic nephropathy in hypogonadal adult male rats. Can J Physiol Pharmacol 2019; 97:708-720. [PMID: 30970225 DOI: 10.1139/cjpp-2018-0572] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
This study examined the effect of the aromatase inhibitor letrozole (0.5 mg/kg) alone or in combination with the angiotensin-receptor blocker valsartan (30 mg/kg) against streptozocin-induced diabetic nephropathy (DN) in hypogonadal (HG) rats for 12 weeks. First, we tested the HG effect on hormone levels, inflammatory cytokines, and oxidative stress in nondiabetic (ND) and diabetic (D) rats. HG was induced with the luteinizing hormone-releasing hormone antagonist cetrorelix (0.71 mg/kg). Diabetes enhanced hormonal hypogonadism and increased inflammation and oxidative stress. Next, experiments examined the effect of early letrozole and valsartan intervention on DN in HG rats. HG-ND and HG-D rats were treated with letrozole alone or in combination with valsartan. HG-D rats developed proteinuria and had increased blood urea nitrogen and creatinine, and histopathological evidence of renal injury, including glomerular hypertrophy and mesangial expansion. Valsartan alone or in combination with letrozole reduced proteinuria, improved renal functions, and reduced diabetes-induced renal angiotensin II. Both agents ameliorated nuclear factor kappa light chain enhancer of activated B cells, interleukin 1β, interleukin 6, and tumor necrosis factor alpha levels. The combination decreased superoxide dismutase, malondialdehyde, and glutathione peroxidase levels, and prevented glomerular hypertrophy. In HG-D rats, valsartan reduced renal collagen IV and transforming growth factor-beta 1, especially when the testosterone level was corrected by letrozole. Thus, normalizing testosterone and inhibiting renal angiotensin II have a renoprotective effect against DN in HG male rats.
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Affiliation(s)
- Samy Makary
- a Department of Physiology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
| | - Mohamed Abdo
- a Department of Physiology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
| | - Wael Abdo Hassan
- b Department of Pathology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt.,c Department of Basic Sciences, Sulaiman Al-Rajhi College of Medicine, Kingdom of Saudi Arabia
| | - Mona K Tawfik
- d Department of Pharmacology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
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O'Neill J, Jasionek G, Drummond SE, Brett O, Lucking EF, Abdulla MA, O'Halloran KD. Renal cortical oxygen tension is decreased following exposure to long-term but not short-term intermittent hypoxia in the rat. Am J Physiol Renal Physiol 2019; 316:F635-F645. [PMID: 30648908 DOI: 10.1152/ajprenal.00254.2018] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Chronic kidney disease (CKD) occurs in more than 50% of patients with obstructive sleep apnea (OSA). However, the impact of intermittent hypoxia (IH) on renal function and oxygen homeostasis is unclear. Male Sprague-Dawley rats were exposed to IH (270 s at 21% O2; 90 s hypoxia, 6.5% O2 at nadir) for 4 h [acute IH (AIH)] or to chronic IH (CIH) for 8 h/day for 2 wk. Animals were anesthetized and surgically prepared for the measurement of mean arterial pressure (MAP), and left renal excretory function, renal blood flow (RBF), and renal oxygen tension (Po2). AIH had no effect on MAP (123 ± 14 vs. 129 ± 14 mmHg, means ± SE, sham vs. IH). The CIH group was hypertensive (122 ± 9 vs. 144 ± 15 mmHg, P < 0.05). Glomerular filtration rate (GFR) (0.92 ± 0.27 vs. 1.33 ± 0.33 ml/min), RBF (3.8 ± 1.5 vs. 7.2 ± 2.4 ml/min), and transported sodium (TNa) (132 ± 39 vs. 201 ± 47 μmol/min) were increased in the AIH group (all P < 0.05). In the CIH group, GFR (1.25 ± 0.28 vs. 0.86 ± 0.28 ml/min, P < 0.05) and TNa (160 ± 39 vs. 120 ± 40 μmol/min, P < 0.05) were decreased, while RBF (4.13 ± 1.5 vs. 3.08 ± 1.5 ml/min) was not significantly different. Oxygen consumption (QO2) was increased in the AIH group (6.76 ± 2.60 vs. 13.60 ± 7.77 μmol/min, P < 0.05), but it was not significantly altered in the CIH group (3.97 ± 2.63 vs. 6.82 ± 3.29 μmol/min). Cortical Po2 was not significantly different in the AIH group (46 ± 4 vs. 46 ± 3 mmHg), but it was decreased in the CIH group (44 ± 5 mmHg vs. 38 ± 2 mmHg, P < 0.05). For AIH, renal oxygen homeostasis was preserved through a maintained balance between O2 supply (RBF) and consumption (GFR). For CIH, mismatched TNa and QO2 reflect inefficient O2 utilization and, thereby, sustained decrease in cortical Po2.
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Affiliation(s)
- Julie O'Neill
- Department of Physiology, School of Medicine, College of Medicine and Health, University College Cork , Cork , Ireland
| | - Greg Jasionek
- Department of Physiology, School of Medicine, College of Medicine and Health, University College Cork , Cork , Ireland
| | - Sarah E Drummond
- Department of Physiology, School of Medicine, College of Medicine and Health, University College Cork , Cork , Ireland
| | - Orla Brett
- Department of Physiology, School of Medicine, College of Medicine and Health, University College Cork , Cork , Ireland
| | - Eric F Lucking
- Department of Physiology, School of Medicine, College of Medicine and Health, University College Cork , Cork , Ireland
| | - Mohammed A Abdulla
- Department of Physiology, School of Medicine, College of Medicine and Health, University College Cork , Cork , Ireland
| | - Ken D O'Halloran
- Department of Physiology, School of Medicine, College of Medicine and Health, University College Cork , Cork , Ireland
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Vieira LD, Farias JS, de Queiroz DB, Cabral EV, Lima-Filho MM, Sant'Helena BR, Aires RS, Ribeiro VS, Santos-Rocha J, Xavier FE, Paixão AD. Oxidative stress induced by prenatal LPS leads to endothelial dysfunction and renal haemodynamic changes through angiotensin II/NADPH oxidase pathway: Prevention by early treatment with α-tocopherol. Biochim Biophys Acta Mol Basis Dis 2018; 1864:3577-3587. [DOI: 10.1016/j.bbadis.2018.09.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 09/04/2018] [Accepted: 09/17/2018] [Indexed: 11/16/2022]
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10
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Franzén S, Palm F. Endothelin type A receptor inhibition normalises intrarenal hypoxia in rats used as a model of type 1 diabetes by improving oxygen delivery. Diabetologia 2015; 58:2435-42. [PMID: 26173672 DOI: 10.1007/s00125-015-3690-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2015] [Accepted: 06/17/2015] [Indexed: 12/17/2022]
Abstract
AIMS/HYPOTHESIS Intrarenal tissue hypoxia, secondary to increased oxygen consumption, has been suggested as a unifying mechanism for the development of diabetic nephropathy. Increased endothelin-1 signalling via the endothelin type A receptor (ETA-R) has been shown to contribute to the development of chronic kidney disease, but its role in kidney oxygen homeostasis is presently unknown. METHODS The effects of acute ETA-R inhibition (8 nmol/l BQ-123 for 30-40 min directly into the left renal artery) on kidney function and oxygen metabolism were investigated in normoglycaemic control and insulinopenic male Sprague Dawley rats (55 mg/kg streptozotocin intravenously 2 weeks before the main experiment) used as a model of type 1 diabetes. RESULTS Local inhibition of ETA-R in the left kidney did not affect BP in either the control or the diabetic rats. As previously reported, diabetic rats displayed increased kidney oxygen consumption resulting in tissue hypoxia in both the kidney cortex and medulla. The inhibition of ETA-Rs restored normal kidney tissue oxygen availability in the diabetic kidney by increasing renal blood flow, but did not affect oxygen consumption. Furthermore, ETA-R inhibition reduced the diabetes-induced glomerular hyperfiltration and increased the urinary sodium excretion. Kidney function in normoglycaemic control rats was largely unaffected by BQ-123 treatment, although it also increased renal blood flow and urinary sodium excretion in these animals. CONCLUSIONS/INTERPRETATION Acutely reduced intrarenal ETA-R signalling results in significantly improved oxygen availability in the diabetic kidney secondary to elevated renal perfusion. Thus, the beneficial effects of ETA-R inhibition on kidney function in diabetes may be due to improved intrarenal oxygen homeostasis.
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Affiliation(s)
- Stephanie Franzén
- Experimental Renal Medicine, Division of Drug Research, Department of Medical and Health Sciences, Faculty of Health Sciences, Linköping University, 58185, Linköping, Sweden.
- Center for Medical Image Science and Visualization, Linköping University, Linköping, Sweden.
| | - Fredrik Palm
- Experimental Renal Medicine, Division of Drug Research, Department of Medical and Health Sciences, Faculty of Health Sciences, Linköping University, 58185, Linköping, Sweden
- Center for Medical Image Science and Visualization, Linköping University, Linköping, Sweden
- Department of Medical Cell Biology, Division of Integrative Physiology, Uppsala University, Uppsala, Sweden
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11
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Xiang L, Mittwede PN, Clemmer JS. Glucose Homeostasis and Cardiovascular Alterations in Diabetes. Compr Physiol 2015; 5:1815-39. [DOI: 10.1002/cphy.c150001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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12
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Layton AT. Recent advances in renal hemodynamics: insights from bench experiments and computer simulations. Am J Physiol Renal Physiol 2015; 308:F951-5. [PMID: 25715984 DOI: 10.1152/ajprenal.00008.2015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 02/23/2015] [Indexed: 01/08/2023] Open
Abstract
It has been long known that the kidney plays an essential role in the control of body fluids and blood pressure and that impairment of renal function may lead to the development of diseases such as hypertension (Guyton AC, Coleman TG, Granger Annu Rev Physiol 34: 13-46, 1972). In this review, we highlight recent advances in our understanding of renal hemodynamics, obtained from experimental and theoretical studies. Some of these studies were published in response to a recent Call for Papers of this journal: Renal Hemodynamics: Integrating with the Nephron and Beyond.
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Affiliation(s)
- Anita T Layton
- Department of Mathematics, Duke University, Durham, North Carolina
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13
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Kim SM, Mizel D, Qin Y, Huang Y, Schnermann J. Blood pressure, heart rate and tubuloglomerular feedback in A1AR-deficient mice with different genetic backgrounds. Acta Physiol (Oxf) 2015; 213:259-67. [PMID: 25182861 DOI: 10.1111/apha.12377] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Revised: 07/28/2014] [Accepted: 08/27/2014] [Indexed: 01/11/2023]
Abstract
AIM Differences in genetic background between control mice and mice with targeted gene mutations have been recognized as a potential cause for phenotypic differences. In this study, we have used A1AR-deficient mice in a C57Bl/6 and SWR/J congenic background to assess the influence of background on the effect of A1AR-deficiency on cardiovascular and renal functional parameters. METHODS In A1AR+/+ and A1AR-/- mice in C57Bl/6 and SWR/J congenic backgrounds, we assessed blood pressure and heart rate using radio-telemetry, plasma renin concentrations and tubuloglomerular feedback. RESULTS We did not detect significant differences in arterial blood pressure (MAP) and heart rates (HR) between A1AR+/+ and A1AR-/- mice in either C57Bl/6, SWR/J or mixed backgrounds. MAP and HR were significantly higher in SWR/J than in C57Bl/6 mice. A high NaCl intake increased MAP in A1AR-/- mice on C57Bl/6 background while there was less or no salt sensitivity in the SWR/J background. No significant differences in plasma renin concentration were detected between A1AR-/- and A1AR+/+ mice in any of the strains. Tubuloglomerular feedback was found to be absent in A1AR-/- mice with SWR/J genetic background. CONCLUSIONS While this study confirmed important differences between inbred mouse strains, we did not identify phenotypic modifications of A1AR-related effects on blood pressure, heart rate and plasma renin by differences in genetic background.
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Affiliation(s)
- S. M. Kim
- Department of Physiology; Chonbuk National University Medical School; Jeonju South Korea
- National Institute of Diabetes and Digestive and Kidney Diseases; NIH; Bethesda Maryland
| | - D. Mizel
- National Institute of Diabetes and Digestive and Kidney Diseases; NIH; Bethesda Maryland
| | - Y. Qin
- National Institute of Diabetes and Digestive and Kidney Diseases; NIH; Bethesda Maryland
| | - Y. Huang
- National Institute of Diabetes and Digestive and Kidney Diseases; NIH; Bethesda Maryland
| | - J. Schnermann
- National Institute of Diabetes and Digestive and Kidney Diseases; NIH; Bethesda Maryland
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Abstract
PURPOSE OF REVIEW The purpose of this review is to provide an update on the current knowledge regarding the role of the intrarenal rennin-angiotensin system (RAS) in the regulation of glomerular function including glomerular dynamics and filtration rate, glomerular permeability and structural alterations during chronic increases in intrarenal angiotensin (Ang) II. RECENT FINDINGS Recent studies have continued to delineate the complex interactions among the various RAS components that participate in regulating glomerular function. Although Ang II acting on AT1 receptors remains as the predominant influence on glomerular dynamics, some of these effects are indirectly mediated by Ang II modulating the sensitivity of the macula densa tubuloglomerular feedback mechanism as well as the more recently described feedback mechanism from the connecting tubule. Interestingly, the actions of Ang II on these systems cause opposite effects on glomerular function demonstrating the complexities associated with the influences of Ang II on glomerular function. When chronically elevated, Ang II also stimulates and/or interacts with other factors, including reactive oxygen species, cytokines and growth factors and other hormones or paracrine agents, to elicit structural alterations. SUMMARY Recent studies have provided further evidence for the presence of many components of the RAS in glomerular structures, which supports the importance of locally produced angiotensin peptides to regulate glomerular haemodynamics, filtration rate and macromolecular permeability and contribute to fibrosis and glomerular injury when inappropriately augmented.
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Blantz RC, Singh P. Glomerular and tubular function in the diabetic kidney. Adv Chronic Kidney Dis 2014; 21:297-303. [PMID: 24780458 DOI: 10.1053/j.ackd.2014.03.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Revised: 03/09/2014] [Accepted: 03/10/2014] [Indexed: 01/11/2023]
Abstract
Diabetes mellitus with its attendant complications is a significant cause of morbidity and mortality with diabetic nephropathy being the leading cause of end stage renal disease in the Western world. Characteristic structural and functional changes in the kidney early in the course of diabetes have been shown to have enduring effects on the progression of disease. A better understanding of the mechanisms underlying these changes is imperative to the development of new therapeutic strategies. Renal hypertrophy and hyperfiltration along with proximal tubular hyperreabsorption are among the distinctive features of early diabetic nephropathy. Additionally, there are particular alterations in the sensitivity of the glomerular and tubular function to dietary salt intake in early diabetes. Herein, we focus on these early physiologic changes and discuss some of the primary and secondary mechanisms discovered in recent years which lead to these alterations in kidney function.
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Patinha D, Afonso J, Sousa T, Morato M, Albino-Teixeira A. Activation of adenosine receptors improves renal antioxidant status in diabetic Wistar but not SHR rats. Ups J Med Sci 2014; 119:10-8. [PMID: 24195577 PMCID: PMC3916712 DOI: 10.3109/03009734.2013.851748] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Diabetes and hypertension independently contribute to renal injury, and the major mechanisms involved are increased reactive oxygen species (ROS) bioavailability and renin-angiotensin system (RAS) activation. We investigated the role of adenosine in controlling ROS production and RAS activation associated with renal dysfunction in hypertension and diabetes. METHODS Fourteen days after induction of diabetes with streptozotocin in 12-week-old male Wistar and spontaneously hypertensive (SHR) rats, animals were treated during 7 days with 2-chloroadenosine (CADO group, 5 mg/kg/d), a stable analogue of adenosine, or underwent a sham operation procedure. At the end of the study (day 21), intra-arterial systolic blood pressure (SBP) was measured, and 24-h urine and plasma samples and renal tissue were collected. RESULTS CADO treatment decreased the plasma glucose concentration and glucose and protein excretion by more than 30% in both strains. CADO treatment decreased SBP in diabetic SHR rats (143 ± 8 versus 114 ± 4 mmHg, p < 0.05), but not in diabetic Wistar rats. The hypotensive effect of CADO was associated to a ∼70% increase in plasma angiotensinogen (AGT) concentration and a ∼50% decrease in urinary AGT excretion. CADO also caused a decrease in medullary and cortical hydrogen peroxide production of about 40%, which was associated with a proportional increase in glutathione peroxidase (GPx) activity in diabetic Wistar but not in diabetic SHR animals. CONCLUSIONS These results suggest that activation of adenosine receptors improves renal antioxidant capacity in diabetic Wistar but not SHR rats, although it improves glucose metabolism in both strains. Furthermore, activation of adenosine receptors does not seem to be directly influencing AGT production.
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Affiliation(s)
- Daniela Patinha
- Departamento de Farmacologia e Terapêutica, Faculdade de Medicina, Universidade do Porto, Porto, Portugal
- Neurofarmacologia, Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Joana Afonso
- Departamento de Farmacologia e Terapêutica, Faculdade de Medicina, Universidade do Porto, Porto, Portugal
| | - Teresa Sousa
- Departamento de Farmacologia e Terapêutica, Faculdade de Medicina, Universidade do Porto, Porto, Portugal
| | - Manuela Morato
- Departamento de Farmacologia e Terapêutica, Faculdade de Medicina, Universidade do Porto, Porto, Portugal
- Neurofarmacologia, Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
- Laboratório de Farmacologia, Departamento de Ciências do Medicamento, Faculdade de Farmácia, REQUIMTE, Universidade do Porto, Porto, Portugal
| | - António Albino-Teixeira
- Departamento de Farmacologia e Terapêutica, Faculdade de Medicina, Universidade do Porto, Porto, Portugal
- Neurofarmacologia, Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
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Proteomics and diabetic nephropathy: what have we learned from a decade of clinical proteomics studies? J Nephrol 2014; 27:221-8. [PMID: 24567069 DOI: 10.1007/s40620-014-0044-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Accepted: 10/15/2013] [Indexed: 02/02/2023]
Abstract
Diabetic nephropathy (DN) has become the most frequent cause of chronic kidney disease worldwide due to the constant increase of the incidence of type 2 diabetes mellitus in developed and developing countries. The understanding of the pathophysiological mechanisms of human diseases through a large-scale characterization of the protein content of a biological sample is the key feature of the proteomics approach to the study of human disease. We discuss the main results of over 10 years of tissue and urine proteomics studies applied to DN in order to understand how far we have come and how far we still have to go before obtaining a full comprehension of the molecular mechanisms involved in the pathogenesis of DN and identifying reliable biomarkers for accurate management of patients.
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Tikellis C, Brown R, Head GA, Cooper ME, Thomas MC. Angiotensin-converting enzyme 2 mediates hyperfiltration associated with diabetes. Am J Physiol Renal Physiol 2014; 306:F773-80. [PMID: 24477684 DOI: 10.1152/ajprenal.00264.2013] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The degradation of ANG II by angiotensin-converting enzyme 2 (ACE2), leading to the formation of ANG(1-7), is an important step in the regulation of the renin-angiotensin-aldosterone system (RAAS), and one that is significantly altered in the diabetic kidney. This study examined the role of ACE2 in the hyperfiltration associated with diabetes. Streptozotocin diabetes was induced in male C57BL6 mice and ACE2 knockout (KO) mice. C57BL6 mice were further randomized to receive the selective ACE2 inhibitor MLN-4760. After 2 wk of study, animals were subjected to micropuncture experiments. The renal reserve was further assessed in C57BL6 mice and ACE2 KO mice after exposure to a high-protein diet. The induction of diabetes in wild-type mice was associated with increased renal ACE2 activity, hyperfiltration, and renal hypertrophy. On micropuncture, diabetes was associated with increased tubular free flow and stop-flow pressure, enhanced tubuloglomerular feedback reactivity, and an increased maximal response indicative of increased glomerular hydrostatic capillary pressure. Each of these increases were prevented in diabetic ACE2 KO mice and diabetic mice treated with a selective ACE2 inhibitor for 2 wk. However, unlike chronically treated animals, ACE2 inhibition with MLN-4760 had no acute effect on stop-flow pressure or tubuloglomerular feedback reactivity. ACE2 KO mice also failed to increase their creatinine clearance in response to a high-protein diet. The results of our study suggest that ACE2 plays a key role in the recruitment of the renal reserve and hyperfiltration associated with diabetes.
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Affiliation(s)
- Chris Tikellis
- Baker IDI Heart and Diabetes Institute, PO Box 6492, St Kilda Central, Melbourne 8008, Victoria, Australia.
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Tan RJ, Zhou L, Zhou D, Lin L, Liu Y. Endothelin receptor a blockade is an ineffective treatment for adriamycin nephropathy. PLoS One 2013; 8:e79963. [PMID: 24265790 PMCID: PMC3825716 DOI: 10.1371/journal.pone.0079963] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Accepted: 09/28/2013] [Indexed: 11/24/2022] Open
Abstract
Endothelin is a vasoconstricting peptide that plays a key role in vascular homeostasis, exerting its biologic effects via two receptors, the endothelin receptor A (ETA) and endothelin receptor B (ETB). Activation of ETA and ETB has opposing actions, in which hyperactive ETA is generally vasoconstrictive and pathologic. Selective ETA blockade has been shown to be beneficial in renal injuries such as diabetic nephropathy and can improve proteinuria. Atrasentan is a selective pharmacologic ETA blocker that preferentially inhibits ETA activation. In this study, we evaluated the efficacy of ETA blockade by atrasentan in ameliorating proteinuria and kidney injury in murine adriamycin nephropathy, a model of human focal segmental glomerulosclerosis. We found that ETA expression was unaltered during the course of adriamycin nephropathy. Whether initiated prior to injury in a prevention protocol (5 mg/kg/day, i.p.) or after injury onset in a therapeutic protocol (7 mg/kg or 20 mg/kg three times a week, i.p.), atrasentan did not significantly affect the initiation and progression of adriamycin-induced albuminuria (as measured by urinary albumin-to-creatinine ratios). Indices of glomerular damage were also not improved in atrasentan-treated groups, in either the prevention or therapeutic protocols. Atrasentan also failed to improve kidney function as determined by serum creatinine, histologic damage, and mRNA expression of numerous fibrosis-related genes such as collagen-I and TGF-β1. Therefore, we conclude that selective blockade of ETA by atrasentan has no effect on preventing or ameliorating proteinuria and kidney injury in adriamycin nephropathy.
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Affiliation(s)
- Roderick J. Tan
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Lili Zhou
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Dong Zhou
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Lin Lin
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Youhua Liu
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
- * E-mail:
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