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Gao ZX, Wei QC, Shu TT, Li ST, Zhou R, Li MY, Mao ZH, Liu DW, Liu ZS, Wu P. Kir4.1 deletion prevents salt-sensitive hypertension in early streptozotocin-induced diabetic mice via Na + -Cl - cotransporter in the distal convoluted tubule. J Hypertens 2023; 41:958-970. [PMID: 37016934 DOI: 10.1097/hjh.0000000000003419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/06/2023]
Abstract
OBJECTIVES Functional impairment of renal sodium handling and blood pressure (BP) homeostasis is an early characteristic manifestation of type 1 diabetes. However, the underlying mechanisms remain unclear. METHODS Metabolic cages, radio-telemetry, immunoblotting, and electrophysiology were utilized to examine effects of high salt (8% NaCl, HS) intake on Na + /K + balance, BP, Na + -Cl - cotransporter (NCC) function, and basolateral K + channel activity in the distal convoluted tubule (DCT) under diabetic conditions. RESULTS Improper Na + balance, hypernatremia, and a mild but significant increase in BP were found in streptozotocin (STZ)-induced diabetic mice in response to HS intake for 7 days. Compared to the vehicle, STZ mice showed increased Kir4.1 expression and activity in the DCT, a more negative membrane potential, higher NCC abundance, and enhanced hydrochlorothiazide-induced natriuretic effect. However, HS had no significant effect on basolateral Kir4.1 expression/activity and DCT membrane potential, or NCC activity under diabetic conditions, despite a downregulation in phosphorylated NCC abundance. In contrast, HS significantly downregulated the expression of Na + -H + exchanger 3 (NHE3) and cleaved epithelial sodium channel-γ in STZ mice, despite an increase in NHE3 abundance after STZ treatment. Kir4.1 deletion largely abolished STZ-induced upregulation of NCC expression and prevented BP elevation during HS intake. Interestingly, HS causes severe hypokalemia in STZ-treated kidney-specific Kir4.1 knockout (Ks-Kir4.1 KO) mice and lead to death within a few days, which could be attributed to a higher circulating aldosterone level. CONCLUSIONS We concluded that Kir4.1 is required for upregulating NCC activity and may be essential for developing salt-sensitive hypertension in early STZ-induced diabetes.
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Affiliation(s)
- Zhong-Xiuzi Gao
- Traditional Chinese Medicine Integrated Department of Nephrology, The First Affiliated Hospital of Zhengzhou University
- Institute of Nephrology, Zhengzhou University
- Henan Province Clinical Research Center for Kidney Disease
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, China
| | - Qi-Chao Wei
- Traditional Chinese Medicine Integrated Department of Nephrology, The First Affiliated Hospital of Zhengzhou University
- Institute of Nephrology, Zhengzhou University
- Henan Province Clinical Research Center for Kidney Disease
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, China
| | - Ting-Ting Shu
- Traditional Chinese Medicine Integrated Department of Nephrology, The First Affiliated Hospital of Zhengzhou University
- Institute of Nephrology, Zhengzhou University
- Henan Province Clinical Research Center for Kidney Disease
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, China
| | - Shu-Ting Li
- Traditional Chinese Medicine Integrated Department of Nephrology, The First Affiliated Hospital of Zhengzhou University
- Institute of Nephrology, Zhengzhou University
- Henan Province Clinical Research Center for Kidney Disease
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, China
| | - Rui Zhou
- Traditional Chinese Medicine Integrated Department of Nephrology, The First Affiliated Hospital of Zhengzhou University
- Institute of Nephrology, Zhengzhou University
- Henan Province Clinical Research Center for Kidney Disease
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, China
| | - Ming-Yan Li
- Traditional Chinese Medicine Integrated Department of Nephrology, The First Affiliated Hospital of Zhengzhou University
- Institute of Nephrology, Zhengzhou University
- Henan Province Clinical Research Center for Kidney Disease
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, China
| | - Zi-Hui Mao
- Traditional Chinese Medicine Integrated Department of Nephrology, The First Affiliated Hospital of Zhengzhou University
- Institute of Nephrology, Zhengzhou University
- Henan Province Clinical Research Center for Kidney Disease
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, China
| | - Dong-Wei Liu
- Traditional Chinese Medicine Integrated Department of Nephrology, The First Affiliated Hospital of Zhengzhou University
- Institute of Nephrology, Zhengzhou University
- Henan Province Clinical Research Center for Kidney Disease
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, China
| | - Zhang-Suo Liu
- Traditional Chinese Medicine Integrated Department of Nephrology, The First Affiliated Hospital of Zhengzhou University
- Institute of Nephrology, Zhengzhou University
- Henan Province Clinical Research Center for Kidney Disease
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, China
| | - Peng Wu
- Traditional Chinese Medicine Integrated Department of Nephrology, The First Affiliated Hospital of Zhengzhou University
- Institute of Nephrology, Zhengzhou University
- Henan Province Clinical Research Center for Kidney Disease
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, China
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Cobb MB, Wu W, Attipoe EM, Johnson AC, Garrett MR. Nephron-deficient HSRA rats exhibit renal injury with age but have limited renal damage from streptozotocin-induced hyperglycemia. Am J Physiol Renal Physiol 2021; 320:F1093-F1105. [PMID: 33843272 PMCID: PMC8285653 DOI: 10.1152/ajprenal.00487.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 04/05/2021] [Accepted: 04/05/2021] [Indexed: 01/13/2023] Open
Abstract
Hypertension and diabetes are the greatest factors influencing the progression of chronic kidney disease (CKD). Investigation into the role of nephron number in CKD alone or with hypertension has revealed a strong inverse relationship between the two; however, not much is known about the connection between nephron number and diabetic kidney disease. The heterogeneous stock-derived model of unilateral renal agenesis (HSRA) rat, a novel model of nephron deficiency, provides a unique opportunity to study the association between nephron number and hypertension and diabetes on CKD. HSRA rats exhibit failure of one kidney to develop in 50-75% of offspring, whereas the remaining offspring are born with two kidneys. Rats born with one kidney (HSRA-S) develop significant renal injury with age compared with two-kidney littermates (HSRA-C). The induction of hypertension as a secondary stressor leads to significantly more renal injury in HSRA-S compared with HSRA-C rats and nephrectomized HSRA-C (HSRA-UNX) rats. The present study sought to address the hypothesis that nephron deficiency in the HSRA rat would hasten renal injury in the presence of a secondary stressor of hyperglycemia. HSRA animals did not exhibit diabetes-related traits at any age; thus, streptozotocin (STZ) was used to induce hyperglycemia in HSRA-S, HSRA-C, and HSRA-UNX rats. STZ- and vehicle-treated animals were followed for 15 wk. STZ-treated animals developed robust hyperglycemia, but in contrast to the response to hypertension, neither HSRA-S nor HSRA-UNX animals developed proteinuria compared with vehicle treatment. In total, our data indicate that hyperglycemia from STZ alone does not have a significant impact on the onset or progression of injury in young one-kidney HSRA animals.NEW & NOTEWORTHY The HSRA rat, a novel model of nephron deficiency, provides a unique opportunity to study the association between nephron number and confounding cardiovascular complications that impact kidney health. Although hypertension was previously shown to exacerbate renal injury in young HSRA animals, diabetic hyperglycemia did not lead to worse renal injury, suggesting that nephron number has limited impact on kidney injury, at least in this model.
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Affiliation(s)
- Meredith B Cobb
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Wenjie Wu
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Esinam M Attipoe
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Ashley C Johnson
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Michael R Garrett
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
- Department of Medicine (Nephrology), University of Mississippi Medical Center, Jackson, Mississippi
- Department of Pediatrics (Genetics), University of Mississippi Medical Center, Jackson, Mississippi
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Sex differences in the magnitude of diabetic ocular surface complications: Role of serum OGF. Physiol Behav 2021; 237:113436. [PMID: 33905807 DOI: 10.1016/j.physbeh.2021.113436] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 04/21/2021] [Accepted: 04/22/2021] [Indexed: 12/17/2022]
Abstract
Diabetes is associated with dysregulation of the Opioid Growth Factor (OGF) - OGF receptor (OGFr) regulatory pathway leading to elevated OGF levels in serum and tissues. This study was designed to investigate the role of sex on the magnitude of ocular surface complications by direct comparison of male and female type 1 diabetic (T1D) rats. Male and female adult Sprague-Dawley rats were rendered T1D; a cohort of T1D male and female rats received insulin (=T1D-INS). Tear production, corneal surface sensitivity, as well as serum levels of estrogen, testosterone, OGF and OGFr were measured. Multivariate analyses were performed for correlations between sex, condition and magnitude of ocular surface alterations. Significant differences were noted in all parameters tested between male and female Normal, T1D, and T1D-INS animals over the 8-week observation period. Multivariate analyses revealed that the magnitude of complications is greater in female T1D rats and has a strong negative correlation with serum estrogen and OGF. Ocular surface complications associated with T1D have an earlier onset and greater magnitude in female T1D rats than male diabetic animals, and are related to elevated levels of OGF.
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Chen X, Famurewa AC, Tang J, Olatunde OO, Olatunji OJ. Hyperoside attenuates neuroinflammation, cognitive impairment and oxidative stress via suppressing TNF-α/NF-κB/caspase-3 signaling in type 2 diabetes rats. Nutr Neurosci 2021; 25:1774-1784. [PMID: 33722183 DOI: 10.1080/1028415x.2021.1901047] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
OBJECTIVES Literature findings have instituted the role of hyperglycemia-induced oxidative stress and inflammation in the pathogenesis of cognitive derangement in diabetes mellitus (DM). Hyperoside (HYP) is a flavanone glycoside reported to possess diverse pharmacological benefits such as antioxidant and anti-inflammatory properties. The study explored whether HYP could mitigate DM-induced cognitive dysfunction and further elucidate on potential molecular mechanism in rats. METHODS Streptozotocin/high-fat diet-induced diabetic rats were treated orally with HYP (50, 200 and 400 mg/kg/day) for six consecutive weeks. The blood glucose and serum insulin levels, Morris water maze test, intraperitoneal glucose tolerance test, and brain acetylcholinesterase (AChE) activity were determined. The brain expression of inflammatory nuclear factor-kappa B (NF-κB), tumour necrosis factor-alpha (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6), as well as superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH), total antioxidant capacity (TAC), malondialdehyde (MDA), lipid profile and caspase-3 activity were estimated. RESULTS DM evoked hyperlipidemia, hypoinsulinemia, cognitive dysfunction by markedly increased AChE and reduction in learning and memory capacity. Brain activities of SOD and CAT, and levels of TAC and GSH were considerably depressed, whereas levels of IL-1β, IL-6, TNF-α, NF-κB, caspase-3 and MDA were prominently increased. Interestingly, the HYP treatment dose-dependently abrogated the altered cognitive and biochemical parameters. DISCUSSION The results suggested that hyperoside prevents DM-induced cognitive dysfunction, neuroinflammation and oxidative stress via antioxidant, anti-inflammatory and antiapoptotic mechanisms in rats.
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Affiliation(s)
- Xiao Chen
- Second Department of Encephalopathy, Xi'an Encephalopathy Hospital of Traditional Chinese Medicine, Xi'an, People's Republic of China
| | - Ademola C Famurewa
- Department of Medical Biochemistry, Faculty of Basic Medical Sciences, College of Medicine, Alex Ekwueme Federal University, Ndufu-Alike, Ikwo, Nigeria
| | - Jian Tang
- School of Chinese Medicine, Bozhou University, Anhui, People's Republic of China
| | - Oladipupo Odunayo Olatunde
- International Center of Excellence in Seafood Science and Innovation, Faculty of Agro-Industry, Prince of Songkla University, Hat Yai, Songkhla, Thailand
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Almatroodi SA, Alnuqaydan AM, Babiker AY, Almogbel MA, Khan AA, Husain Rahmani A. 6-Gingerol, a Bioactive Compound of Ginger Attenuates Renal Damage in Streptozotocin-Induced Diabetic Rats by Regulating the Oxidative Stress and Inflammation. Pharmaceutics 2021; 13:pharmaceutics13030317. [PMID: 33670981 PMCID: PMC7997342 DOI: 10.3390/pharmaceutics13030317] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 02/24/2021] [Accepted: 02/24/2021] [Indexed: 02/06/2023] Open
Abstract
The aim of present study is to investigate the role of 6-gingerol in ameliorating the renal injury in streptozotocin (STZ)-induced diabetic rats. The diabetes was induced by using a single dose of freshly prepared STZ (55 mg/kg body weight) intraperitoneally which causes the degeneration of pancreatic Langerhans islet β-cells. The diabetic rats were treated with oral gavage of 6-gingerol (10 mg/kg b.w.). The treatment plan was continued for 8 weeks successively and the body weight and fasting blood glucose levels were weekly checked. The biochemical parameters like lipid profile, kidney profile, antioxidant enzyme levels, lipid peroxidation and anti-inflammatory marker levels were investigated after the treatment plant. The pathological condition of kidneys was examined by haematoxylin-eosin (H&E) staining besides this analysis of NF-κB protein expression by immuno-histochemistry was performed. Some of the major parameters in diabetes control vs. normal control were reported as fasting blood glucose (234 ± 10 vs. 102 ± 8 mg/dL), serum creatinine (109.7 ± 7.2 vs. 78.9 ± 4.5 μmol/L) and urea (39.9 ± 1.8 vs. 18.6 mg/dL), lipid profile levels were significantly enhanced in diabetic rats. Moreover, diabetic rats were marked with decreased antioxidant enzyme levels and increased inflammatory markers. Treatment with 6-gingerol significantly restored the fasting blood glucose level, hyperlipidaemia, Malondialdehyde (MDA) and inflammatory marker levels, NF-κB protein expression and augmented the antioxidant enzyme levels in the kidneys of diabetic rats. The kidney damage was significantly normalized by the treatment of 6-gingerol and it provides an evidence that this novel compound plays a significant role in the protection of kidney damage. These findings demonstrate that 6-gingerol reduces lipid parameters, inflammation and oxidative stress in diabetic rats, thereby inhibiting the renal damage. Our results demonstrate that use of 6-gingerol could be a novel therapeutic approach to prevent the kidney damage associated with the diabetes mellitus.
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Affiliation(s)
- Saleh A. Almatroodi
- Department of Medical Laboratories, College of Applied Medical Sciences, Qassim University, Buraydah 51452, Saudi Arabia; (S.A.A.); (A.Y.B.); (M.A.A.)
| | - Abdullah M. Alnuqaydan
- Department of Medical Biotechnology, College of Applied Medical Sciences, Qassim University, Buraydah 51452, Saudi Arabia;
| | - Ali Yousif Babiker
- Department of Medical Laboratories, College of Applied Medical Sciences, Qassim University, Buraydah 51452, Saudi Arabia; (S.A.A.); (A.Y.B.); (M.A.A.)
| | - Mashael Abdullah Almogbel
- Department of Medical Laboratories, College of Applied Medical Sciences, Qassim University, Buraydah 51452, Saudi Arabia; (S.A.A.); (A.Y.B.); (M.A.A.)
| | - Amjad Ali Khan
- Department of Basic Health Sciences, College of Applied Medical Sciences, Qassim University, Buraydah 51452, Saudi Arabia;
| | - Arshad Husain Rahmani
- Department of Medical Laboratories, College of Applied Medical Sciences, Qassim University, Buraydah 51452, Saudi Arabia; (S.A.A.); (A.Y.B.); (M.A.A.)
- Correspondence: ; Tel.: +966-16-3800050 (ext. 15477)
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Molecular Mechanisms of SGLT2 Inhibitor on Cardiorenal Protection. Int J Mol Sci 2020; 21:ijms21217833. [PMID: 33105763 PMCID: PMC7660105 DOI: 10.3390/ijms21217833] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 10/20/2020] [Accepted: 10/20/2020] [Indexed: 12/14/2022] Open
Abstract
The development of sodium-glucose transporter 2 inhibitor (SGLT2i) broadens the therapeutic strategies in treating diabetes mellitus. By inhibiting sodium and glucose reabsorption from the proximal tubules, the improvement in insulin resistance and natriuresis improved the cardiovascular mortality in diabetes mellitus (DM) patients. It has been known that SGLT2i also provided renoprotection by lowering the intraglomerular hypertension by modulating the pre- and post- glomerular vascular tone. The application of SGLT2i also provided metabolic and hemodynamic benefits in molecular aspects. The recent DAPA-CKD trial and EMPEROR-Reduced trial provided clinical evidence of renal and cardiac protection, even in non-DM patients. Therefore, the aim of the review is to clarify the hemodynamic and metabolic modulation of SGLT2i from the molecular mechanism.
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Alaofi AL. Sinapic Acid Ameliorates the Progression of Streptozotocin (STZ)-Induced Diabetic Nephropathy in Rats via NRF2/HO-1 Mediated Pathways. Front Pharmacol 2020; 11:1119. [PMID: 32792955 PMCID: PMC7390867 DOI: 10.3389/fphar.2020.01119] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 07/09/2020] [Indexed: 12/13/2022] Open
Abstract
Diabetic neuropathy (DN) is a complicated inauspicious outcome of diabetes, like other abnormalities of diabetes the cause of DN is still vague and it may be the result of various pathological conditions leading up to end-stage renal failure. The present study examines the efficacy of sinapic acid (SA) in streptozotocin (STZ)-induced DN nephropathy and the linked pathway. Twenty-four rats were equally divided randomly into four categories: Normal control (NC), STZ, STZ + SA 20 mg/kg bw, and STZ + SA 40 mg/kg bw. After 8 weeks they were evaluated for ratio of renal index, the fasting blood glucose (FBG), blood urea nitrogen (BUN), 24 h urea protein, serum creatinine (SCr), reduced glutathione peroxidase (GPx), superoxide dismutase (SOD), lipid peroxidation (MDA), tumor necrosis factor α (TNFα), interleukin (IL)-6, as well as lipid profile total cholesterol (TC), total triglycerides (TG), very low density lipoprotein (VLDL), low density lipoprotein (LDL), and high density lipoprotein (HDL) levels. Additionally, histomorphology and ultrastructure of the kidneys were also assessed. Protein expression levels of transforming growth factor-β1 (TGF-β1), nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), IκBα protein (IkBα), anti-apoptotic protein BCl2, nuclear factor kappa B (NF-kB), and Bax were examined. We observed that SA 20 mg/kg bw and 40 mg/kg bw pretreatment significantly and dose-dependently upregulated the protein expression of HO-1, Nrf2, IKBα, and Bcl-2 but downregulated the protein expression of NF-κB, proposing that the nephroprotective mechanism of SA is due to its antioxidant and anti-inflammatory activity; SA prevents the release of cytokines and inflammatory markers (TNFα and IL-6), upregulates antioxidant defense enzymes, and reduces lipid peroxidation, as well as nitric oxide, and anti-apoptotic activity, which may be influenced by the regulation of TNF-α, IL-6, Bcl-2, NF-kB, and BaX via the Nrf2/HO-1 pathway in STZ induced DN. Thus, our results suggest that SA ameliorates the development of STZ-induced DN in rats via NRF2/HO-1 mediated pathways. Further comprehensive studies are required for complete elucidation of the fundamental mechanisms.
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Affiliation(s)
- Ahmed L. Alaofi
- Department of Pharmaceutics, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
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Ahmed OM, Ali TM, Abdel Gaid MA, Elberry AA. Effects of enalapril and paricalcitol treatment on diabetic nephropathy and renal expressions of TNF-α, p53, caspase-3 and Bcl-2 in STZ-induced diabetic rats. PLoS One 2019; 14:e0214349. [PMID: 31527864 PMCID: PMC6748411 DOI: 10.1371/journal.pone.0214349] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2019] [Accepted: 08/05/2019] [Indexed: 01/04/2023] Open
Abstract
This study aimed to assess the renopreventive effect of enalapril and/or paricalcitol on streptozotocin (STZ) diabetes-induced nephropathy and to elucidate their mechanisms of action through investigation of the effects on renal oxidative stress, antioxidant defense system and expressions of TNF-α, p53, caspase-3, and Bcl-2. Diabetes mellitus was induced in fasting male Wistar rats by single intraperitoneal injection of STZ (45 mg /kg b.w.) dissolved in citrate buffer (pH 4.5). Ten days after STZ injection, the diabetic rats were treated with enalapril (25 mg/l of drinking water) and/or paricalcitol (8 μg/kg b.w. per os) dissolved in 5% DMSO daily for 4 weeks. The obtained data revealed that the treatment of diabetic Wistar rats with enalapril and/or paricalcitol led to significant decreases in the elevated serum urea, uric acid, creatinine, sodium and potassium levels; thereby reflecting the improvement of the impaired kidney function. The deteriorated kidney lipid peroxidation, GSH content and GST and catalase activities in diabetic rats were significantly ameliorated as a result of treatment with enalapril and/or paricalcitol. The elevated fasting and post-prandial serum glucose levels and the lowered serum insulin and C-peptide levels were also improved. The treatment with enalapril and paricalcitol in combination was the most potent in decreasing the elevated serum glucose levels. Moreover, the treatment of diabetic rats successfully prevented the diabetes-induced histopathological deleterious changes of kidney and islets of Langerhans of pancreas. In association, the immunohistochemically detected pro-inflammatory cytokine, TNF-α, and apoptotic mediators, p53 and caspase-3, were remarkably decreased in kidney of diabetic rats as a result of treatment while the expression of anti-apoptotic protein Bcl-2 was increased. Based on these findings, it can be concluded that enalapril and paricalcitol alone or in combination can prevent STZ diabetes-induced nephropathy through amelioration of the glycemic state and antioxidant defense system together with the suppression of oxidative stress, inflammation and apoptosis. However, the treatment of diabetic rats with enalapril and paricalcitol in combination has no further significant improvement effects on renal function and damage when compared with enalapril or paclitaxel treated diabetic groups.
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Affiliation(s)
- Osama M. Ahmed
- Experimental Obesity and Diabetes Research Lab, Physiology Division, Zoology Department, Faculty of Science, Beni-Suef University, Beni-Suef, Egypt
- * E-mail: ,
| | - Tarek M. Ali
- Department of Clinical Laboratories, College of Applied Medical Sciences, Taif University, Taif, Saudi Arabia
- Department of Physiology, Faculty of Medicine, Beni-Suef University, Beni-Suef, Egypt
| | - Mohamed A. Abdel Gaid
- Experimental Obesity and Diabetes Research Lab, Physiology Division, Zoology Department, Faculty of Science, Beni-Suef University, Beni-Suef, Egypt
| | - Ahmed A. Elberry
- Clinical Pharmacology Department, Faculty of Medicine, Beni-Suef University, Beni-suef, Egypt
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Drummond HA, Stec DE. βENaC acts as a mechanosensor in renal vascular smooth muscle cells that contributes to renal myogenic blood flow regulation, protection from renal injury and hypertension. ACTA ACUST UNITED AC 2015; 1:1-9. [PMID: 27928552 DOI: 10.17554/j.issn.2410-0579.2015.01.12] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Pressure-induced constriction (also known as the "myogenic response") is an important mechanodependent response in small renal arteries and arterioles. The response is initiated by vascular smooth muscle cell (VSMC) stretch due to an increase in intraluminal pressure and leads to vasoconstriction. The myogenic response has two important roles as a mechanism of local blood flow autoregulation and protection against systemic blood pressure-induced microvascular damage. However, the molecular mechanisms underlying initiation of myogenic response are unresolved. Although several molecules have been considered initiators of the response, our laboratory has focused on the role of degenerin proteins because of their strong evolutionary link to mechanosensing in the nematode. Our laboratory has addressed the hypothesis that certain degenerin proteins act as mechanosensors in VSMCs. This article discusses the importance of a specific degenerin protein, β Epithelial Na+ Channel (βENaC), in pressure-induced vasoconstriction, renal blood flow and susceptibility to renal injury. We propose that loss of the renal myogenic constrictor response delays the correction of renal blood flow that occurs with fluctuations in systemic pressure, which allows pressure swings to be transmitted to the microvasculature, thus increasing the susceptibility to renal injury and hypertension. The role of βENaC in myogenic regulation is independent of tubular βENaC and thus represents a non-tubular role for βENaC in renal-cardiovascular homeostasis.
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Affiliation(s)
- Heather A Drummond
- Department of Physiology and Biophysics, Center for Excellence in Cardiovascular-Renal Research, University of Mississippi Medical Center, Jackson, MS, 39216-4505
| | - David E Stec
- Department of Physiology and Biophysics, Center for Excellence in Cardiovascular-Renal Research, University of Mississippi Medical Center, Jackson, MS, 39216-4505
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Brouwers O, Niessen PMG, Miyata T, Østergaard JA, Flyvbjerg A, Peutz-Kootstra CJ, Sieber J, Mundel PH, Brownlee M, Janssen BJA, De Mey JGR, Stehouwer CDA, Schalkwijk CG. Glyoxalase-1 overexpression reduces endothelial dysfunction and attenuates early renal impairment in a rat model of diabetes. Diabetologia 2014; 57:224-35. [PMID: 24162587 DOI: 10.1007/s00125-013-3088-5] [Citation(s) in RCA: 107] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Accepted: 10/02/2013] [Indexed: 02/02/2023]
Abstract
AIMS/HYPOTHESIS In diabetes, advanced glycation end-products (AGEs) and the AGE precursor methylglyoxal (MGO) are associated with endothelial dysfunction and the development of microvascular complications. In this study we used a rat model of diabetes, in which rats transgenically overexpressed the MGO-detoxifying enzyme glyoxalase-I (GLO-I), to determine the impact of intracellular glycation on vascular function and the development of early renal changes in diabetes. METHODS Wild-type and Glo1-overexpressing rats were rendered diabetic for a period of 24 weeks by intravenous injection of streptozotocin. Mesenteric arteries were isolated to study ex vivo vascular reactivity with a wire myograph and kidneys were processed for histological examination. Glycation was determined by mass spectrometry and immunohistochemistry. Markers for inflammation, endothelium dysfunction and renal dysfunction were measured with ELISA-based techniques. RESULTS Diabetes-induced formation of AGEs in mesenteric arteries and endothelial dysfunction were reduced by Glo1 overexpression. Despite the absence of advanced nephrotic lesions, early markers of renal dysfunction (i.e. increased glomerular volume, decreased podocyte number and diabetes-induced elevation of urinary markers albumin, osteopontin, kidney-inflammation-molecule-1 and nephrin) were attenuated by Glo1 overexpression. In line with this, downregulation of Glo1 in cultured endothelial cells resulted in increased expression of inflammation and endothelium dysfunction markers. In fully differentiated cultured podocytes incubation with MGO resulted in apoptosis. CONCLUSIONS/INTERPRETATION This study shows that effective regulation of the GLO-I enzyme is important in the prevention of vascular intracellular glycation, endothelial dysfunction and early renal impairment in experimental diabetes. Modulating the GLO-I pathway therefore may provide a novel approach to prevent vascular complications in diabetes.
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Affiliation(s)
- Olaf Brouwers
- Laboratory for Metabolism and Vascular Medicine, Division of General Internal Medicine, Department of Internal Medicine, Maastricht University Medical Center, Universiteitssingel 50, P.O. Box 616 (box 14), 6200 MD, Maastricht, the Netherlands,
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Brouwers O, de Vos-Houben JMJ, Niessen PMG, Miyata T, van Nieuwenhoven F, Janssen BJA, Hageman G, Stehouwer CDA, Schalkwijk CG. Mild oxidative damage in the diabetic rat heart is attenuated by glyoxalase-1 overexpression. Int J Mol Sci 2013; 14:15724-39. [PMID: 23899787 PMCID: PMC3759882 DOI: 10.3390/ijms140815724] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Revised: 06/26/2013] [Accepted: 07/08/2013] [Indexed: 12/13/2022] Open
Abstract
Diabetes significantly increases the risk of heart failure. The increase in advanced glycation endproducts (AGEs) and oxidative stress have been associated with diabetic cardiomyopathy. We recently demonstrated that there is a direct link between AGEs and oxidative stress. Therefore, the aim of the current study was to investigate if a reduction of AGEs by overexpression of the glycation precursor detoxifying enzyme glyoxalase-I (GLO-I) can prevent diabetes-induced oxidative damage, inflammation and fibrosis in the heart. Diabetes was induced in wild-type and GLO-I transgenic rats by streptozotocin. After 24-weeks of diabetes, cardiac function was monitored with ultrasound under isoflurane anesthesia. Blood was drawn and heart tissue was collected for further analysis. Analysis with UPLC-MSMS showed that the AGE Nε-(1-carboxymethyl)lysine and its precursor 3-deoxyglucosone were significantly elevated in the diabetic hearts. Markers of oxidative damage, inflammation, and fibrosis were mildly up-regulated in the heart of the diabetic rats and were attenuated by GLO-I overexpression. In this model of diabetes, these processes were not accompanied by significant changes in systolic heart function, i.e., stroke volume, fractional shortening and ejection fraction. This study shows that 24-weeks of diabetes in rats induce early signs of mild cardiac alterations as indicated by an increase of oxidative stress, inflammation and fibrosis which are mediated, at least partially, by glycation.
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Affiliation(s)
- Olaf Brouwers
- Laboratory for Metabolism and Vascular Medicine, Division of General Internal Medicine, Department of Internal Medicine, Maastricht University Medical Center, Universiteitssingel 50, PO Box 616 (#14), 6200MD Maastricht, The Netherlands; E-Mails: (P.M.G.N.); (C.D.A.S.); (C.G.S.)
| | - Joyce M. J. de Vos-Houben
- Department of Toxicology, Maastricht University Medical Center, 6200MD Maastricht, The Netherlands; E-Mails: (J.M.J.V.-H.); (G.H.)
| | - Petra M. G. Niessen
- Laboratory for Metabolism and Vascular Medicine, Division of General Internal Medicine, Department of Internal Medicine, Maastricht University Medical Center, Universiteitssingel 50, PO Box 616 (#14), 6200MD Maastricht, The Netherlands; E-Mails: (P.M.G.N.); (C.D.A.S.); (C.G.S.)
| | - Toshio Miyata
- Centre of Translational and Advanced Research, Tohoku University, Sendai 980-8575, Japan; E-Mail:
| | - Frans van Nieuwenhoven
- Department of Physiology, Maastricht University Medical Center, 6200MD Maastricht, The Netherlands; E-Mail:
| | - Ben J. A. Janssen
- Department of Pharmacology, Maastricht University Medical Center, 6200MD Maastricht, The Netherlands; E-Mail:
| | - Geja Hageman
- Department of Toxicology, Maastricht University Medical Center, 6200MD Maastricht, The Netherlands; E-Mails: (J.M.J.V.-H.); (G.H.)
| | - Coen D. A. Stehouwer
- Laboratory for Metabolism and Vascular Medicine, Division of General Internal Medicine, Department of Internal Medicine, Maastricht University Medical Center, Universiteitssingel 50, PO Box 616 (#14), 6200MD Maastricht, The Netherlands; E-Mails: (P.M.G.N.); (C.D.A.S.); (C.G.S.)
| | - Casper G. Schalkwijk
- Laboratory for Metabolism and Vascular Medicine, Division of General Internal Medicine, Department of Internal Medicine, Maastricht University Medical Center, Universiteitssingel 50, PO Box 616 (#14), 6200MD Maastricht, The Netherlands; E-Mails: (P.M.G.N.); (C.D.A.S.); (C.G.S.)
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12
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Polichnowski AJ, Griffin KA, Long J, Williamson GA, Bidani AK. Blood pressure-renal blood flow relationships in conscious angiotensin II- and phenylephrine-infused rats. Am J Physiol Renal Physiol 2013; 305:F1074-84. [PMID: 23825067 DOI: 10.1152/ajprenal.00111.2013] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Chronic ANG II infusion in rodents is widely used as an experimental model of hypertension, yet very limited data are available describing the resulting blood pressure-renal blood flow (BP-RBF) relationships in conscious rats. Accordingly, male Sprague-Dawley rats (n = 19) were instrumented for chronic measurements of BP (radiotelemetry) and RBF (Transonic Systems, Ithaca, NY). One week later, two or three separate 2-h recordings of BP and RBF were obtained in conscious rats at 24-h intervals, in addition to separate 24-h BP recordings. Rats were then administered either ANG II (n = 11, 125 ng·kg(-1)·min(-1)) or phenylephrine (PE; n = 8, 50 mg·kg(-1)·day(-1)) as a control, ANG II-independent, pressor agent. Three days later the BP-RBF and 24-h BP recordings were repeated over several days. Despite similar increases in BP, PE led to significantly greater BP lability at the heart beat and very low frequency bandwidths. Conversely, ANG II, but not PE, caused significant renal vasoconstriction (a 62% increase in renal vascular resistance and a 21% decrease in RBF) and increased variability in BP-RBF relationships. Transfer function analysis of BP (input) and RBF (output) were consistent with a significant potentiation of the renal myogenic mechanism during ANG II administration, likely contributing, in part, to the exaggerated reductions in RBF during periods of BP elevations. We conclude that relatively equipressor doses of ANG II and PE lead to greatly different ambient BP profiles and effects on the renal vasculature when assessed in conscious rats. These data may have important implications regarding the pathogenesis of hypertension-induced injury in these models of hypertension.
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Affiliation(s)
- Aaron J Polichnowski
- Correspondence: A. K. Bidani, Loyola Univ. Medical Center, 2160 South First Ave., Maywood, IL 60153.
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13
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Abstract
PURPOSE OF REVIEW Despite apparent blood pressure (BP) control and renin-angiotensin system (RAS) blockade, the chronic kidney disease (CKD) outcomes have been suboptimal. Accordingly, this review is addressed to renal microvascular and autoregulatory impairments that underlie the enhanced dynamic glomerular BP transmission in CKD progression. RECENT FINDINGS Clinical data suggest that failure to achieve adequate 24-h BP control is likely contributing to the suboptimal outcomes in CKD. Whereas evidence continues to accumulate regarding the importance of preglomerular autoregulatory impairment to the dynamic glomerular BP transmission, emerging data indicate that nitric oxide-mediated efferent vasodilation may play an important role in mitigating the consequences of glomerular hypertension. By contrast, the vasoconstrictor effects of angiotensin II are expected to potentially reduce glomerular barotrauma and possibly enhance ischemic injury. When adequate BP measurement methods are used, the evidence for BP-independent injury initiating mechanisms is considerably weaker and the renoprotection by RAS blockade largely parallels its antihypertensive effectiveness. SUMMARY Adequate 24-h BP control presently offers the most feasible intervention for reducing glomerular BP transmission and improving suboptimal outcomes in CKD. Investigations addressed to improving myogenic autoregulation and/or enhancing nitric oxide-mediated efferent dilation in addition to the more downstream mediators may provide additional future therapeutic targets.
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Drummond HA. βENaC is a molecular component of a VSMC mechanotransducer that contributes to renal blood flow regulation, protection from renal injury, and hypertension. Front Physiol 2012; 3:341. [PMID: 22973231 PMCID: PMC3428779 DOI: 10.3389/fphys.2012.00341] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Accepted: 08/07/2012] [Indexed: 12/23/2022] Open
Abstract
Pressure-induced constriction (also known as the “myogenic response”) is an important mechano-dependent response in certain blood vessels. The response is mediated by vascular smooth muscle cells (VSMCs) and characterized by a pressure-induced vasoconstriction in small arteries and arterioles in the cerebral, mesenteric, cardiac, and renal beds. The myogenic response has two important roles; it is a mechanism of blood flow autoregulation and provides protection against systemic blood pressure-induced damage to delicate microvessels. However, the molecular mechanism(s) underlying initiation of myogenic response is unclear. Degenerin proteins have a strong evolutionary link to mechanotransduction in the nematode. Our laboratory has addressed the hypothesis that these proteins may also act as mechanosensors in certain mammalian tissues such as VSMCs and arterial baroreceptor neurons. This article discusses the importance of a specific degenerin protein, β Epithelial Na+ Channel (βENaC) in pressure-induced vasoconstriction in renal vessels and arterial baroreflex function as determined in a mouse model of reduced βENaC (βENaC m/m). We propose that loss of baroreflex sensitivity (due to loss of baroreceptor βENaC) increases blood pressure variability, increasing the likelihood and magnitude of upward swings in systemic pressure. Furthermore, loss of the myogenic constrictor response (due to loss of VSMC βENaC) will permit those pressure swings to be transmitted to the microvasculature in βENaC m/m mice, thus increasing the susceptibility to renal injury and hypertension.
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Affiliation(s)
- Heather A Drummond
- Department of Physiology and Biophysics, University of Mississippi Medical Center Jackson, MS, USA
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15
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Sima CA, Koeners MP, Joles JA, Braam B, Magil AB, Cupples WA. Increased susceptibility to hypertensive renal disease in streptozotocin-treated diabetic rats is not modulated by salt intake. Diabetologia 2012; 55:2246-55. [PMID: 22562180 DOI: 10.1007/s00125-012-2569-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2012] [Accepted: 04/02/2012] [Indexed: 01/13/2023]
Abstract
AIMS/HYPOTHESIS In early type 1 diabetes mellitus, renal salt handling is dysregulated, so that the glomerular filtration rate becomes inversely proportional to salt intake. The salt paradox occurs in both humans and rats and, with low salt intake, results in diabetic hyperfiltration. We tested whether increased salt intake could reduce the susceptibility to injury of non-clipped kidneys in diabetic rats with pre-existing Goldblatt hypertension. METHODS Male Long-Evans rats were made hypertensive and half were then made diabetic. Blood glucose was maintained at ~20-25 mmol/l by insulin implants. One half of each received only the salt in normal chow (1% by weight) and the other half received added salt in drinking water to equal 2.7% by weight of food intake. Weekly 24 h blood pressure records were acquired by telemetry during the 4-month experiment. RESULTS Systolic blood pressure was not affected by diabetes or increased salt intake, alone or together. Autoregulation was highly efficient in the non-clipped kidney of both intact and diabetic rats. Histological examination showed minor injury in the clipped kidney, which did not differ among groups. The non-clipped kidney showed extensive pressure-dependent glomerular and vascular injury in both intact and diabetic rats. CONCLUSIONS/INTERPRETATION The relationship between pressure and injury was shifted toward lower blood pressure in diabetic rats, indicating that diabetes increased the susceptibility of the kidney to injury despite preservation of autoregulation. The increased susceptibility was not affected by high salt intake in the diabetic rats, thus disproving the hypothesis.
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Affiliation(s)
- C A Sima
- Department of Biology, University of Victoria, Victoria, BC, Canada
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Anigbogu CN, Speakman RO, Silcox DL, Brown LV, Brown DR, Gong MC, Patwardhan AR, Reynolds LR, Karounos DG, Burgess DE, Baldridge BR, Randall DC. Extended longitudinal analysis of arterial pressure and heart rate control in unanesthetized rats with type 1 diabetes. Auton Neurosci 2012; 170:20-9. [PMID: 22809731 DOI: 10.1016/j.autneu.2012.06.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Revised: 06/20/2012] [Accepted: 06/21/2012] [Indexed: 11/15/2022]
Abstract
We recorded arterial pressure (BP) and heart rate (HR) in type-1 diabetic rats vs. controls for >6 months. Diabetic rats (DIAB) were maintained on insulin from the day glucose >250 mg/dl ("Day 0"). Weight was similar between groups until ~3 weeks before Day 0 when the weight in DIAB transiently lagged the controls (CONT); this difference was maintained throughout the study, but both groups otherwise gained weight in parallel. Plasma glucose attained 371 ± 109 (SD) mg/dl by day 1 in DIAB. Mean BP was similar across groups, and declined through the initial 4-6 months in both the CONT (at -0.06 ± 0.04 mmHg/day) and in the DIAB (at -0.14 ± 0.21 mmHg/day; NS vs. CONT). HR in the CONT (Month 1: 341 ± 13 bpm) exceeded DIAB (325 ± 25 bpm) through ~6 months after Day 0, and also decreased progressively over this period in CONT (-0.19 ± 0.14 bpm/day) and DIAB (-0.29 ± 0.23 bpm/day; NS vs. CONT) before leveling. The BP power within 0.35-0.45 Hz changed during the 90 min before vs. after the transition from dark to light, and light to dark; there were no between group differences. The slope of the log-log linear portion of the BP power spectrum between 1.0/h and 1/min was similar across groups, and increased in both from month 1 to month 6. Regulatory mechanisms maintain similar profiles in BP and HR in diabetic vs. control animals through the initial half year of the disease.
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Affiliation(s)
- Chikodi N Anigbogu
- Department of Physiology, College of Medicine, University of Lagos, Idi-Araba, Nigeria
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17
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Takata H, Takeda Y, Zhu A, Cheng Y, Yoneda T, Demura M, Yagi K, Karashima S, Yamagishi M. Protective effects of mineralocorticoid receptor blockade against neuropathy in experimental diabetic rats. Diabetes Obes Metab 2012; 14:155-62. [PMID: 21951301 DOI: 10.1111/j.1463-1326.2011.01499.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
AIMS Mineralocorticoid receptor (MR) blockade is an effective treatment for hypertension and diabetic nephropathy. There are no data on the effects of MR blockade on diabetic peripheral neuropathy (DPN). The aim of this study was to determine whether MRs are present in the peripheral nerves and to investigate the effectiveness of MR blockade on DPN in streptozotocin (STZ)-induced diabetic rats. METHODS Expression of MR protein and messenger RNA (mRNA) was examined in the peripheral nerves using Western blot analysis and RT-PCR. We next studied the effects of the selective MR antagonist eplerenone and the angiotensin II receptor blocker candesartan on motor and sensory nerve conduction velocity (NCV), morphometric changes and cyclooxygenase-2 (COX-2) gene and NF-κB protein expression in the peripheral nerves of STZ-induced diabetic rats. RESULTS Expression of MR protein and mRNA in peripheral nerves was equal to that in the kidney. Motor NCV was significantly improved by 8 weeks of treatment with either eplerenone (39.1 ± 1.2 m/s) or candesartan (46.4 ± 6.8 m/s) compared with control diabetic rats (33.7 ± 2.0 m/s) (p < 0.05). Sensory NCV was also improved by treatment with candesartan or eplerenone in diabetic rats. Eplerenone and candesartan caused significant improvement in mean myelin fibre area and mean myelin area compared with control diabetic rats (p < 0.05). COX-2 mRNA and NF-κB protein were significantly elevated in the peripheral nerves of diabetic rats compared with control rats, and treatment with eplerenone or candesartan reduced these changes in gene expression (p < 0.05). CONCLUSION MR blockade may have neuroprotective effects on DPN.
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Affiliation(s)
- H Takata
- Division of Endocrinology and Hypertension, Department of Internal Medicine, Graduate School of Medical Science, Kanazawa University, Kanazawa, Japan
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18
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Locke M, Anderson J. NF-κB activation in organs from STZ-treated rats. Appl Physiol Nutr Metab 2011; 36:121-7. [PMID: 21326386 DOI: 10.1139/h10-094] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Nuclear factor kappa B (NF-κB) is a ubiquitously expressed transcription factor comprised of various subunits (p50 (NF-κB1), p52 (NF-κB2), p65 (RelA), RelB, and c-Rel). Activation of certain NF-κB subunits appears to foster an inflammatory state that may promote the development of disease. Thus characterizing the specific NF-κB subunits may provide insight into the pathogenesis of certain diseases. The purpose of this study was to determine if 1 month of a diabetic state, induced by streptozotocin (STZ) treatment, alters the constitutive level of NF-κB activation, its subunit composition, or the content of NF-κB-related proteins in rodent liver, kidney, spleen, and heart. Diabetes was induced in male Sprague-Dawley rats by a single tail vein injection of STZ (55 mg·kg-1 body weight). After 30 days, the heart, liver, spleen, and kidney were assessed for NF-κB activation and subunit composition with electrophoretic mobility shift assay (EMSA), and p50 and p65 subunit content was assessed with Western blotting. In diabetic animals, the constitutive level of NF-κB activation was reduced in liver, but was unchanged in kidney, spleen, and heart. EMSA supershifts showed the predominant subunit in the activated NF-κB complexes from both diabetic and control animals to be p50, although the p65 subunit was detected in NF-κB complexes from diabetic hearts. The content of p50 was unaltered in all diabetic tissues examined, whereas the content of p65 was increased only in hearts from diabetic animals. These findings support the idea that a diabetic state may induce specific changes in NF-κB subunit composition in certain tissues.
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Affiliation(s)
- Marius Locke
- Faculty of Physical Education and Health, University of Toronto, 55 Harbord Street, Toronto, ON M5S 2W6, Canada.
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19
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Dhaunsi GS, Yousif MHM, Akhtar S, Chappell MC, Diz DI, Benter IF. Angiotensin-(1-7) prevents diabetes-induced attenuation in PPAR-gamma and catalase activities. Eur J Pharmacol 2010; 638:108-14. [PMID: 20447391 DOI: 10.1016/j.ejphar.2010.04.030] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2009] [Revised: 04/20/2010] [Accepted: 04/22/2010] [Indexed: 02/07/2023]
Abstract
The mechanisms by which angiotensin-(1-7) [Ang-(1-7)] exerts its beneficial effects on end-organ damage associated with diabetes and hypertension are not well understood. The purpose of this study was A) to compare the effects of apocynin with Ang-(1-7) on renal vascular dysfunction and NADPH oxidase activity in a combined model of diabetes and hypertension and B) to further determine whether chronic treatment with Ang-(1-7) can modulate renal catalase, and peroxisome proliferator activated receptor- gamma (PPAR-gamma) levels in streptozotocin-induced diabetes in both normotensive Wistar Kyoto rats (WKY) and in spontaneously hypertensive rats (SHR). Apocynin or Ang-(1-7) treatment for one month starting at the onset of diabetes similarly attenuated elevation of renal NADPH oxidase activity in the diabetic SHR kidney and reduced the degree of proteinuria and hyperglycemia, but had little or modest effect on reducing mean arterial pressure. Both drugs also attenuated the diabetes-induced increase in renal vascular responsiveness to endothelin-1. Induction of diabetes in WKY and SHR animals resulted in significantly reduced renal catalase activity and in PPAR-gamma mRNA and protein levels. Treatment with Ang-(1-7) significantly prevented diabetes-induced reduction in catalase activity and the reduction in PPAR-gamma mRNA and protein levels in both animal models. Taken together, these data suggest that activation of Ang-(1-7)-mediated signaling could be an effective way to prevent the elevation of NADPH oxidase activity and inhibition of PPAR-gamma and catalase activities in diabetes and/or hypertension.
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Affiliation(s)
- Gursev S Dhaunsi
- Department of Pediatrics, Faculty of Medicine, Kuwait University, Kuwait
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20
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Abstract
PURPOSE OF REVIEW Diabetes mellitus is the primary cause of end-stage renal disease, yet the mechanisms underlying diabetic nephropathy remain ill-defined. The widely accepted opinion holds that events occurring early during the course of diabetes engender the eventual decline in renal function. This review will summarize recent advances (published January 2008 through June 2009) regarding the renal vascular and glomerular functional changes that occur during the early stage of diabetes. RECENT FINDINGS Reduced C-peptide levels and increased cyclooxygenase-2 activity both seem to promote diabetic hyperfiltration, presumably via effects on afferent arteriolar tone. In addition, exaggerated tonic influences of K+ channels on afferent arteriolar function likely act in concert with impaired Ca2+ influx responses to changes in membrane potential to promote vasodilation. Mechanisms underlying these changes remain largely speculative. Diabetes may also alter autoregulation of renal blood flow and glomerular filtration rate, as well as provoke afferent arteriolar dilation secondary to alterations in proximal tubular reabsorption; however, conflicting evidence continues to flood the literature concerning these events. SUMMARY New evidence has expanded our appreciation of the complexity of events that promote preglomerular vasodilation during the early stage of diabetes; however, it seems that the more we know, the less we understand.
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Mohan M, Waghulde H, Kasture S. Effect of pomegranate juice on Angiotensin II-induced hypertension in diabetic wistar rats. Phytother Res 2009; 24 Suppl 2:S196-203. [DOI: 10.1002/ptr.3090] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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do Carmo JM, Tallam LS, Roberts JV, Brandon EL, Biglane J, da Silva AA, Hall JE. Impact of obesity on renal structure and function in the presence and absence of hypertension: evidence from melanocortin-4 receptor-deficient mice. Am J Physiol Regul Integr Comp Physiol 2009; 297:R803-12. [PMID: 19605765 DOI: 10.1152/ajpregu.00187.2009] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The purpose of this study was to determine the long-term impact of obesity and related metabolic abnormalities in the absence and presence of hypertension on renal injury and salt-sensitivity of blood pressure. Markers of renal injury and blood pressure salt sensitivity were assessed in 52- to 55-wk-old normotensive melanocortin-4 receptor-deficient (MC4R-/-) mice and lean C57BL/6J wild-type (WT) mice and in 22-wk-old MC4R-/- and WT mice made hypertensive by N(G)-nitro-L-arginine methyl ester (L-NAME) in the drinking water for 8 wk. Old MC4R-/- mice were 60% heavier, hyperinsulinemic, and hyperleptinemic but had similar mean arterial pressure (MAP) as WT mice (115 +/- 2 and 117 +/- 2 mmHg) on normal salt diet (0.4% NaCl). A high-salt diet (4.0% NaCl) for 12 days did not raise MAP in obese or lean mice [DeltaMAP: MC4R (-/-) 4 +/- 2 mmHg; WT, 2 +/- 1 mmHg]. Obese MC4R-/- mice had 23% greater glomerular tuft area and moderately increased GFR compared with WT mice. Bowman's space, total glomerular area, mesangial matrix, urinary albumin excretion (UAE), renal TGF-beta and collagen expression were not significantly different between old MC4R-/- and WT mice. Renal lipid content was greater but renal macrophage count was markedly lower in MC4R-/- than WT mice. Mild increases in MAP during L-NAME treatment (approximately 16 mmHg) caused small, but greater, elevations in UAE, renal TGF-beta content, and macrophage infiltration in MC4R-/- compared with WT mice without significant changes in glomerular structure. Thus despite long-term obesity and multiple metabolic abnormalities, MC4R-/- mice have no evidence of renal injury or salt-sensitivity of blood pressure. These observations suggest that elevations in blood pressure may be necessary for obesity and related metabolic abnormalities to cause major renal injury or that MC4R-/- mice are protected from renal injury by mechanisms that are still unclear.
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Affiliation(s)
- Jussara M do Carmo
- Dept. of Physiology and Biophysics, Univ. of Mississippi Medical Center, 2500 North State St., Jackson, MS 39216-4505, USA.
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Al-Maghrebi M, Benter IF, Diz DI. Endogenous angiotensin-(1-7) reduces cardiac ischemia-induced dysfunction in diabetic hypertensive rats. Pharmacol Res 2008; 59:263-8. [PMID: 19166939 DOI: 10.1016/j.phrs.2008.12.008] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2008] [Revised: 12/16/2008] [Accepted: 12/22/2008] [Indexed: 12/31/2022]
Abstract
Angiotensin-(1-7) [Ang-(1-7)] is a vasodilator peptide with cardiac and vascular protective properties. We examined the influence of Ang-(1-7), both endogenous and after chronic treatment with the peptide (576microg/(kgday)), on ischemia/reperfusion (I/R)-induced cardiac dysfunction in streptozotocin-treated spontaneously hypertensive rats (diabetic SHR). In isolated perfused hearts, recovery of left ventricular function from 40min of global ischemia was improved significantly in Ang-(1-7)- or captopril-treated diabetic SHR and worsened in animals treated with A779, an Ang-(1-7) receptor (AT((1-7))) antagonist. The beneficial effect of captopril on cardiac recovery was reduced when co-administered with A779. Cardiac NF-kappaB activity appears to be higher in diabetic SHR and treatment with Ang-(1-7) or captopril decreased NF-kappaB activity in diabetic SHR, an effect partially reversed by co-administration of A779. Real-time PCR-based gene array analysis of cardiac tissue revealed that Ang-(1-7) or captopril treatment may reduce expression of several genes of inflammation involved in the NF-kappaB signalling pathway. The data provide for the first time a role for endogenous Ang-(1-7) as well as confirmation that exogenous treatment with the peptide produces cardioprotection. Whether potential anti-inflammatory and transcriptional factor changes are directly linked to the cardioprotection produced by Ang-(1-7) in diabetic SHR remains to be determined.
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Affiliation(s)
- May Al-Maghrebi
- Department of Biochemistry, Faculty of Medicine, Kuwait University, Kuwait
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Glomerular renin angiotensin system in streptozotocin diabetic and Zucker diabetic fatty rats. Transl Res 2008; 151:208-16. [PMID: 18355768 DOI: 10.1016/j.trsl.2008.01.003] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2007] [Revised: 01/04/2008] [Accepted: 01/08/2008] [Indexed: 11/21/2022]
Abstract
Substantial evidence suggests that the intrarenal renin-angiotensin system (RAS) plays a role in the pathogenesis of diabetic nephropathy. Although the glomerular RAS is activated in the streptozotocin (STZ)-diabetic rat, the status of the glomerular RAS in the Zucker diabetic fatty (ZDF) rat, which is a commonly used genetic model of diabetes, is not known. Angiotensinogen (AGT), angiotensin II (Ang II), angiotensin converting enzyme (ACE), and angiotensin converting enzyme 2 (ACE2) were measured in glomeruli isolated from 4-week-old STZ-diabetic rats and 32-week-old ZDF rats. Glomerular injury was evaluated by histopathologic methods. Both STZ-diabetic and ZDF rats exhibited marked hyperglycemia and renal hypertrophy, but only ZDF rats demonstrated proteinuria and glomerulosclerosis. Glomerular AGT and Ang II levels were increased significantly in STZ-diabetic compared with nondiabetic control rats, accompanied by a reduction in ACE2 activity. In contrast, glomerular AGT, Ang II, and ACE2 were similar in ZDF rats and lean controls. ACE levels were not affected by diabetes in either diabetic model. In conclusion, the glomerular RAS is activated in the STZ diabetic rat but not in the ZDF rat despite a similar degree of hyperglycemia. The mechanism of nephropathy in the ZDF rat may involve factors other than hyperglycemia and RAS activation, such as hypertension and hyperlipidemia.
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Xu Q, Wells CC, Garman JH, Asico L, Escano CS, Maric C. Imbalance in sex hormone levels exacerbates diabetic renal disease. Hypertension 2008; 51:1218-24. [PMID: 18259041 DOI: 10.1161/hypertensionaha.107.100594] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Studies suggest that the presence of testosterone exacerbates, whereas the absence of testosterone attenuates, the development of nondiabetic renal disease. However, the effects of the absence of testosterone in diabetic renal disease have not been studied. The study was performed in male Sprague-Dawley nondiabetic, streptozotocin-induced diabetic, and streptozotocin-induced castrated rats (n=10 to 11 per group) for 14 weeks. Diabetes was associated with the following increases: 3.2-fold in urine albumin excretion, 6.3-fold in glomerulosclerosis, 6.0-fold in tubulointerstitial fibrosis, 1.6-fold in collagen type I, 1.2-fold in collagen type IV, 1.3-fold in transforming growth factor-beta protein expression, and 32.7-fold in CD68-positive cell abundance. Diabetes was also associated with a 1.3-fold decrease in matrix metalloproteinase protein expression and activity. Castration further exacerbated all of these parameters. Diabetes was also associated with a 4.7-fold decrease in plasma testosterone, 2.9-fold increase in estradiol, and 2.1-fold decrease in plasma progesterone levels. Castration further decreased plasma testosterone levels but had no additional effects on plasma estradiol and progesterone. These data suggest that diabetes is associated with abnormal sex hormone levels that correlate with the progression of diabetic renal disease. Most importantly, our results suggest an important role for sex hormones in the pathophysiology of diabetic renal complications.
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Affiliation(s)
- Qin Xu
- Department of Medicine, Georgetown University Medical Center, Washington, DC 20057, USA
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Benter IF, Yousif MHM, Dhaunsi GS, Kaur J, Chappell MC, Diz DI. Angiotensin-(1-7) prevents activation of NADPH oxidase and renal vascular dysfunction in diabetic hypertensive rats. Am J Nephrol 2007; 28:25-33. [PMID: 17890855 DOI: 10.1159/000108758] [Citation(s) in RCA: 142] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2007] [Accepted: 08/09/2007] [Indexed: 12/12/2022]
Abstract
BACKGROUND/AIM We examined the influence of chronic treatment with angiotensin-(1-7) [Ang-(1-7)] on renox (renal NADPH oxidase, NOX-4) and the development of renal dysfunction in streptozotocin-treated spontaneously hypertensive rats (diabetic SHR). METHODS Mean arterial pressure, urinary protein and vascular responsiveness of the isolated renal artery to vasoactive agonists were studied in vehicle- or Ang-(1-7)-treated SHR and diabetic SHR. RESULTS Ang-(1-7) decreased the elevated levels of renal NADPH oxidase (NOX) activity and attenuated the activation of NOX-4 gene expression in the diabetic SHR kidney. Ang-(1-7) treatment increased sodium excretion but did not affect mean arterial pressure in diabetic SHR. There was a significant increase in urinary protein (266 +/- 22 mg/24 h) in the diabetic compared to control SHR (112 +/- 13 mg/24 h) and treatment of diabetic SHR with Ang-(1-7) reduced the degree of proteinuria (185 +/- 23 mg/24 h, p < 0.05). Ang-(1-7) treatment also attenuated the diabetes-induced increase in renal vascular responsiveness to endothelin-1, norepinephrine, and angiotensin II in SHR, but significantly increased the vasodilation of the renal artery of SHR and diabetic SHR to the vasodilator agonists. CONCLUSION These results suggest that treatment with Ang-(1-7) constitutes a potential therapeutic strategy to alleviate NOX-mediated oxidative stress and to reduce renal dysfunction in diabetic hypertensive rats.
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Affiliation(s)
- Ibrahim F Benter
- Department of Pharmacology and Toxicology, Faculty of Medicine, Kuwait University, Kuwait.
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