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Ekperikpe US, Mandal S, Holt SJ, Daniels JK, Johnson TD, Cooper JS, Safir SM, Cornelius DC, Williams JM. Metformin reduces insulin resistance and attenuates progressive renal injury in prepubertal obese Dahl salt-sensitive rats. Am J Physiol Renal Physiol 2023; 325:F363-F376. [PMID: 37498548 PMCID: PMC10639024 DOI: 10.1152/ajprenal.00078.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 07/12/2023] [Accepted: 07/24/2023] [Indexed: 07/28/2023] Open
Abstract
Prepubertal obesity is currently an epidemic and is considered as a major risk factor for renal injury. Previous studies have demonstrated that insulin resistance contributes to renal injury in obesity, independent of diabetes. However, studies examining the relationship between insulin resistance and renal injury in obese children are lacking. Recently, we reported that progressive renal injury in Dahl salt-sensitive (SS) leptin receptor mutant (SSLepRmutant) rats was associated with insulin resistance before puberty. Therefore, the aim of the present study was to examine whether decreasing insulin resistance with metformin will reduce renal injury in SSLepRmutant rats. Four-wk-old SS and SSLepRmutant rats were separated into the following two groups: 1) vehicle and 2) metformin (300 mg/kg/day) via chow diet for 4 wk. Chronic administration of metformin markedly reduced insulin resistance and dyslipidemia in SSLepRmutant rats. We did not detect any differences in mean arterial pressure between vehicle and metformin-treated SS and SSLepRmutant rats. Proteinuria was significantly greater in SSLepRmutant rats versus SS rats throughout the study, and metformin administration significantly reduced proteinuria in SSLepRmutant rats. At the end of the protocol, metformin prevented the renal hyperfiltration observed in SSLepRmutant rats versus SS rats. Glomerular and tubular injury and renal inflammation and fibrosis were significantly higher in vehicle-treated SSLepRmutant rats versus SS rats, and metformin reduced these parameters in SSLepRmutant rats. These data suggest that reducing insulin resistance with metformin prevents renal hyperfiltration and progressive renal injury in SSLepRmutant rats before puberty and may be therapeutically useful in managing renal injury during prepubertal obesity.NEW & NOTEWORTHY Childhood/prepubertal obesity is a public health concern that is associated with early signs of proteinuria. Insulin resistance has been described in obese children. However, studies investigating the role of insulin resistance during childhood obesity-associated renal injury are limited. This study provides evidence of an early relationship between insulin resistance and renal injury in a rat model of prepubertal obesity. These data also suggest that reducing insulin resistance with metformin may be renoprotective in obese children.
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Affiliation(s)
- Ubong S Ekperikpe
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi, United States
| | - Sautan Mandal
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi, United States
| | - Stephen J Holt
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi, United States
| | - Jacori K Daniels
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi, United States
| | - Tyler D Johnson
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi, United States
| | - Jonita S Cooper
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi, United States
| | - Sarah M Safir
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi, United States
| | - Denise C Cornelius
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi, United States
| | - Jan M Williams
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi, United States
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Liu T, Hong L, Yang Y, Qiao X, Cai W, Zhong M, Wang M, Zheng Z, Fu Y. Metformin reduces proteinuria in spontaneously hypertensive rats by activating the HIF-2α-VEGF-A pathway. Eur J Pharmacol 2021; 891:173731. [PMID: 33220275 DOI: 10.1016/j.ejphar.2020.173731] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Revised: 11/11/2020] [Accepted: 11/12/2020] [Indexed: 10/23/2022]
Abstract
Metformin has protective effects on diabetic nephropathy. However, the mechanism underlying the renoprotective action of metformin in spontaneously hypertensive rats (SHR) is not completely understood. We determined the role of metformin in proteinuria and investigated the mechanism. We measured the urinary protein concentration (mg/day) in 48-week-old SHR. Matched control animals were of the same genetic strain, Wistar-Kyoto (WKY). The rats received metformin (100 mg/kg/day) or vehicle for 10 months. Metformin improved renal function and reduced the proteinuria (urine protein: 48.4 ± 3.7 vs. 25.4 ± 1.8 mg, P < 0.01) induced by long-term high blood pressure. Metformin increased the production of vascular endothelial growth factor (VEGF)-A in rat kidneys and cultured rat podocytes. Metformin activated hypoxia-inducible factor-2α (Hif-2α) in response to VEGF but did not affect Hif-1α in rat kidneys and cultured rat podocytes. Metformin reduced the proteinuria induced by long-term high blood pressure in vivo and increased the VEGF-A production in rat kidneys and cultured rat podocytes, probably by activating the Hif-2α-VEGF signaling pathway. These findings provide a new mechanism for the renoprotective effects of metformin.
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Affiliation(s)
- Ting Liu
- Department of Critical Care Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, 330006, China
| | - Liying Hong
- Department of Cardiology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, 330006, China; Hypertension Research Instiute of Jiangxi, Nanchang, Jiangxi, 330006, China
| | - Yuan Yang
- Department of Pharmacy, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, 330006, China
| | - Xiandong Qiao
- Department of Cardiology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, 330006, China; Hypertension Research Instiute of Jiangxi, Nanchang, Jiangxi, 330006, China
| | - Wenyao Cai
- Department of Cardiology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, 330006, China
| | - Ming Zhong
- Department of Cardiology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, 330006, China
| | - Menghong Wang
- Department of Cardiology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, 330006, China
| | - Zeqi Zheng
- Department of Cardiology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, 330006, China
| | - Yongnan Fu
- Department of Cardiology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, 330006, China; Hypertension Research Instiute of Jiangxi, Nanchang, Jiangxi, 330006, China.
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Ronn J, Jensen EP, Wewer Albrechtsen NJ, Holst JJ, Sorensen CM. Glucagon-like peptide-1 acutely affects renal blood flow and urinary flow rate in spontaneously hypertensive rats despite significantly reduced renal expression of GLP-1 receptors. Physiol Rep 2018; 5. [PMID: 29233907 PMCID: PMC5727271 DOI: 10.14814/phy2.13503] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 10/17/2017] [Accepted: 10/19/2017] [Indexed: 02/06/2023] Open
Abstract
Glucagon‐like peptide‐1 (GLP‐1) is an incretin hormone increasing postprandial insulin release. GLP‐1 also induces diuresis and natriuresis in humans and rodents. The GLP‐1 receptor is extensively expressed in the renal vascular tree in normotensive rats where acute GLP‐1 treatment leads to increased mean arterial pressure (MAP) and increased renal blood flow (RBF). In hypertensive animal models, GLP‐1 has been reported both to increase and decrease MAP. The aim of this study was to examine expression of renal GLP‐1 receptors in spontaneously hypertensive rats (SHR) and to assess the effect of acute intrarenal infusion of GLP‐1. We hypothesized that GLP‐1 would increase diuresis and natriuresis and reduce MAP in SHR. Immunohistochemical staining and in situ hybridization for the GLP‐1 receptor were used to localize GLP‐1 receptors in the kidney. Sevoflurane‐anesthetized normotensive Sprague–Dawley rats and SHR received a 20 min intrarenal infusion of GLP‐1 and changes in MAP, RBF, heart rate, dieresis, and natriuresis were measured. The vasodilatory effect of GLP‐1 was assessed in isolated interlobar arteries from normo‐ and hypertensive rats. We found no expression of GLP‐1 receptors in the kidney from SHR. However, acute intrarenal infusion of GLP‐1 increased MAP, RBF, dieresis, and natriuresis without affecting heart rate in both rat strains. These results suggest that the acute renal effects of GLP‐1 in SHR are caused either by extrarenal GLP‐1 receptors activating other mechanisms (e.g., insulin) to induce the renal changes observed or possibly by an alternative renal GLP‐1 receptor.
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Affiliation(s)
- Jonas Ronn
- Department of Biomedical Sciences, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Elisa P Jensen
- Department of Biomedical Sciences, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark.,NNF Center for Basic Metabolic Research, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Nicolai J Wewer Albrechtsen
- Department of Biomedical Sciences, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark.,NNF Center for Basic Metabolic Research, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jens Juul Holst
- Department of Biomedical Sciences, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark.,NNF Center for Basic Metabolic Research, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Charlotte M Sorensen
- Department of Biomedical Sciences, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
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Duan Q, Song P, Ding Y, Zou MH. Activation of AMP-activated protein kinase by metformin ablates angiotensin II-induced endoplasmic reticulum stress and hypertension in mice in vivo. Br J Pharmacol 2017; 174:2140-2151. [PMID: 28436023 DOI: 10.1111/bph.13833] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 03/29/2017] [Accepted: 04/16/2017] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND AND PURPOSE Metformin, one of the most frequently prescribed medications for type 2 diabetes, reportedly exerts BP-lowering effects in patients with diabetes. However, the effects and underlying mechanisms of metformin on BP in non-diabetic conditions remain to be determined. The aim of the present study was to determine the effects of metformin on angiotensin II (Ang II) infusion-induced hypertension in vivo. EXPERIMENTAL APPROACH The effects of metformin on BP were investigated in wild-type (WT) C57BL/6J mice and in mice lacking AMP-activated protein kinase α2 (AMPKα2) mice with or without Ang II infusion. Also, the effect of metformin on Ang II-induced endoplasmic reticulum (ER) stress was explored in cultured human vascular smooth muscle cells (hVSMCs). KEY RESULTS Metformin markedly reduced BP in Ang II-infused WT mice but not in AMPKα2-deficient mice. In cultured hVSMCs, Ang II treatment resulted in inactivation of AMPK, as well as the subsequent induction of spliced X-box binding protein-1, phosphorylation of eukaryotic translation initiation factor 2α and expression of glucose-regulated protein 78 kDa, representing three well-characterized ER stress biomarkers. Moreover, AMPK activation by metformin ablated Ang II-induced ER stress in hVSMCs. Mechanistically, metformin-activated AMPKα2 suppressed ER stress by increasing phospholamban phosphorylation. CONCLUSION AND IMPLICATIONS Metformin alleviates Ang II-triggered hypertension in mice by activating AMPKα2, which mediates phospholamban phosphorylation and inhibits Ang II-induced ER stress in vascular smooth muscle cells.
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Affiliation(s)
- Quanlu Duan
- Center for Molecular and Translational Medicine, Georgia State University, Atlanta, GA, USA.,Division of Cardiology, Department Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ping Song
- Center for Molecular and Translational Medicine, Georgia State University, Atlanta, GA, USA
| | - Ye Ding
- Center for Molecular and Translational Medicine, Georgia State University, Atlanta, GA, USA
| | - Ming-Hui Zou
- Center for Molecular and Translational Medicine, Georgia State University, Atlanta, GA, USA
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Pavlov TS, Levchenko V, Ilatovskaya DV, Li H, Palygin O, Pastor-Soler NM, Hallows KR, Staruschenko A. Lack of Effects of Metformin and AICAR Chronic Infusion on the Development of Hypertension in Dahl Salt-Sensitive Rats. Front Physiol 2017; 8:227. [PMID: 28473772 PMCID: PMC5397526 DOI: 10.3389/fphys.2017.00227] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 03/31/2017] [Indexed: 12/19/2022] Open
Abstract
In the kidney, reabsorption via the epithelial sodium channel (ENaC) is involved in long-term blood pressure control. Previously we demonstrated that ENaC hyperactivity is associated with development of salt-sensitive (SS) hypertension in Dahl SS rats. AMP-activated kinase (AMPK), playing a role in cellular energy homeostasis, has been shown to decrease ENaC activity. Here, we tested whether metformin and AICAR, two drugs that activate AMPK, affect the development of salt-induced hypertension. High salt diet significantly increased mean arterial pressure (MAP) in Dahl SS rats. Blood pressure elevation was accompanied by a short-term decline of heart rate and increased circadian arterial pressure dipping. Metformin and AICAR were delivered intravenously at doses of 200 and 20 mg/kg/day, respectively. However, both control and drug-treated groups had similar development of high blood pressure within 3 weeks of 8% NaCl dietary salt intake. In the metformin-treated animals MAP reached 164.9 ± 9.1 mmHg, which was not significantly different from the control group (171.8 ± 5.6 mmHg). Patch clamp analysis revealed that the metformin-treated rats had no difference in the activity of ENaC. AICAR treatment also did not affect the development of hypertension and kidney injury. MAP reached 182.8 ± 4.8 and 178.0 ± 2.8 mmHg in AICAR and vehicle treated groups, respectively. Of note, we found that high-salt diet activated AMPK in the Dahl SS rats, and treatment with these AMPK activators had no significant further effect on AMPK activity. We conclude that AMPK activators, at least under these conditions, do not affect development of hypertension during high-salt diet in the Dahl SS rat model.
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Affiliation(s)
- Tengis S Pavlov
- Department of Physiology, Medical College of WisconsinMilwaukee, WI, USA.,Division of Hypertension and Vascular Research, Henry Ford HospitalDetroit, MI, USA
| | | | | | - Hui Li
- Division of Nephrology and Hypertension, Department of Medicine, Keck School of Medicine, University of Southern California, Los AngelesLos Angeles, CA, USA
| | - Oleg Palygin
- Department of Physiology, Medical College of WisconsinMilwaukee, WI, USA
| | - Nuria M Pastor-Soler
- Division of Nephrology and Hypertension, Department of Medicine, Keck School of Medicine, University of Southern California, Los AngelesLos Angeles, CA, USA
| | - Kenneth R Hallows
- Division of Nephrology and Hypertension, Department of Medicine, Keck School of Medicine, University of Southern California, Los AngelesLos Angeles, CA, USA
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Gallant M, Odei-Addo F, Frost CL, Levendal RA. Biological effects of THC and a lipophilic cannabis extract on normal and insulin resistant 3T3-L1 adipocytes. Phytomedicine 2009; 16:942-949. [PMID: 19345076 DOI: 10.1016/j.phymed.2009.02.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2008] [Revised: 01/23/2009] [Accepted: 02/10/2009] [Indexed: 05/27/2023]
Abstract
Type 2 diabetes, a chronic disease, affects about 150 million people world wide. It is characterized by insulin resistance of peripheral tissues such as liver, skeletal muscle, and fat. Insulin resistance is associated with elevated levels of tumor necrosis factor alpha (TNF-alpha), which in turn inhibits insulin receptor tyrosine kinase autophosphorylation. It has been reported that cannabis is used in the treatment of diabetes. A few reports indicate that smoking cannabis can lower blood glucose in diabetics. Delta(9)-tetrahydrocannabinol (THC) is the primary psychoactive component of cannabis. This study aimed to determine the effect of a lipophilic cannabis extract on adipogenesis, using 3T3-L1 cells, and to measure its effect on insulin sensitivity in insulin resistant adipocytes. Cells were cultured in Dulbecco's modified eagle medium (DMEM) with 10% fetal bovine serum (FBS) and differentiated over a 3 day period for all studies. In the adipogenesis studies, differentiated cells were exposed to the extract in the presence and absence of insulin. Lipid content and glucose uptake was subsequently measured. Insulin-induced glucose uptake increased, while the rate of adipogenesis decreased with increasing THC concentration. Insulin-resistance was induced using TNF-alpha, exposed to the extract and insulin-induced glucose uptake measured. Insulin-induced glucose was increased in these cells after exposure to the extract. Semiquantitative real time polymerase chain reaction (RT-PCR) was performed after ribonucleic acid (RNA) extraction to evaluate the effects of the extract on glucose transporter isotype 4 (GLUT-4), insulin receptor substrate-1 (IRS-1) and IRS-2 gene expression.
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Affiliation(s)
- M Gallant
- Department of Biochemistry & Microbiology, Nelson Mandela Metropolitan University, P.O. Box 77 000, Port Elizabeth 6031, South Africa
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Santuré M, Pitre M, Marette A, Deshaies Y, Lemieux C, Lariviére R, Nadeau A, Bachelard H. Induction of insulin resistance by high-sucrose feeding does not raise mean arterial blood pressure but impairs haemodynamic responses to insulin in rats. Br J Pharmacol 2002; 137:185-96. [PMID: 12208775 PMCID: PMC1573487 DOI: 10.1038/sj.bjp.0704864] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
1. This study was undertaken to further investigate the effects of a sucrose-enriched diet on vascular function and insulin sensitivity in rats. 2. Male Sprague-Dawley rats were randomized to receive a sucrose- or regular rat chow-diet for 4 weeks. A first group of sucrose- and chow-fed rats was instrumented with pulsed Doppler flow probes and intravascular catheters to determine blood pressure, heart rate, regional blood flows and insulin sensitivity in conscious rats. Insulin sensitivity was assessed by the euglycemic hyperinsulinemic clamp technique. Glucose transport activity was examined in isolated muscles by using the glucose analogue [(3)H]-2-deoxy-D-glucose. A second group of sucrose- and chow-fed rats was used to obtain information regarding nitric oxide synthase (NOS) isozymes protein expression in muscles, and determine endothelin content in vascular tissues isolated from both dietary groups. 3. Sucrose feeding was found to induce insulin resistance, but had no effect on resting blood pressure, heart rate, or regional haemodynamics. This insulin resistance was accompanied by alteration in the vascular responses to insulin. Insulin-mediated skeletal muscle vasodilation was impaired, whereas the mesenteric vasoconstrictor response was potentiated in sucrose-fed rats. A reduction in eNOS protein content in muscle and an increase in vascular endothelin peptide were noted in these animals. Moreover, a reduction in insulin-simulated glucose transport activity was also noted in muscles isolated from sucrose-fed rats. 4. Together these data suggest that a cluster of metabolic and haemodynamic abnormalities occur in response to the intake of simple sugars in rats.
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Affiliation(s)
- Marta Santuré
- Hypertension Research Unit, Centre de Recherche du CHUL, CHUQ, Ste-Foy, (Quebec) Canada, G1V 4G2
| | - Maryse Pitre
- Hypertension Research Unit, Centre de Recherche du CHUL, CHUQ, Ste-Foy, (Quebec) Canada, G1V 4G2
| | - André Marette
- Lipid Research Unit, Centre de Recherche du CHUL, CHUQ, Ste-Foy, (Quebec) Canada, G1V 4G2
| | - Yves Deshaies
- Department of Anatomy and Physiology, Centre de Recherche du CHUL, CHUQ, Ste-Foy, (Quebec) Canada, G1V 4G2
| | - Christian Lemieux
- Department of Anatomy and Physiology, Centre de Recherche du CHUL, CHUQ, Ste-Foy, (Quebec) Canada, G1V 4G2
| | - Richard Lariviére
- Research Center of L'Hôtel Dieu de Québec, Centre Hospitalier Universitaire de Québec (CHUQ), Laval University, Quebec, Canada
| | - André Nadeau
- Diabetes Research Unit, Centre Hospitalier Universitaire de Québec (CHUQ), Laval University, Quebec, Canada
| | - Hélène Bachelard
- Hypertension Research Unit, Centre de Recherche du CHUL, CHUQ, Ste-Foy, (Quebec) Canada, G1V 4G2
- Author for correspondence:
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