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Eshraghian A, Taghavi A, Nikoupour H, Nikeghbalian S, Malek-Hosseini SA. Angiotensin receptor blockers might be protective against hepatic steatosis after liver transplantation. BMC Gastroenterol 2023; 23:152. [PMID: 37189076 DOI: 10.1186/s12876-023-02781-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 04/23/2023] [Indexed: 05/17/2023] Open
Abstract
BACKGROUND Hepatic steatosis is an increasing complication in liver transplant recipients. Currently, there is no pharmacologic therapy for treatment of hepatic steatosis after liver transplantation. The aim of this study was to determine the association between use of angiotensin receptor blockers (ARB) and hepatic steatosis in liver transplant recipients. METHODS We conducted a case-control analysis on data from Shiraz Liver Transplant Registry. Liver transplant recipients with and without hepatic steatosis were compared for risk factors including use of ARB. RESULTS A total of 103 liver transplant recipients were included in the study. Thirty five patients treated with ARB and 68 patients (66%) did not receive these medications. In univariate analysis, ARB use (P = 0.002), serum triglyceride (P = 0.006), weight after liver transplantation (P = 0.011) and etiology of liver disease (P = 0.008) were associated with hepatic steatosis after liver transplantation. In multivariate regression analysis, ARB use was associated with lower likelihood of hepatic steatosis in liver transplant recipients (OR = 0.303, 95% CI: 0.117-0.784; P = 0.014). Mean duration of ARB use (P = 0.024) and mean cumulative daily dose of ARB (P = 0.015) were significantly lower in patients with hepatic steatosis. CONCLUSION Our study showed that ARB use was associated with reduced incidence of hepatic steatosis in liver transplant recipients.
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Affiliation(s)
- Ahad Eshraghian
- Shiraz Transplant Center, Abu-Ali Sina Hospital, 71994-67985, Shiraz, Iran.
| | - Alireza Taghavi
- Shiraz Transplant Center, Abu-Ali Sina Hospital, 71994-67985, Shiraz, Iran
- Shiraz Transplant Center, Abu-Ali Sina Hospital, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Hamed Nikoupour
- Shiraz Transplant Center, Abu-Ali Sina Hospital, 71994-67985, Shiraz, Iran
- Shiraz Transplant Center, Abu-Ali Sina Hospital, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Saman Nikeghbalian
- Shiraz Transplant Center, Abu-Ali Sina Hospital, 71994-67985, Shiraz, Iran
- Shiraz Transplant Center, Abu-Ali Sina Hospital, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Seyed Ali Malek-Hosseini
- Shiraz Transplant Center, Abu-Ali Sina Hospital, 71994-67985, Shiraz, Iran
- Shiraz Transplant Center, Abu-Ali Sina Hospital, Shiraz University of Medical Sciences, Shiraz, Iran
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Badr AM, Sherif IO, Mahran YF, Attia HA. Role of Renin-Angiotensin System in the Pathogenesis and Progression of Non-alcoholic Fatty Liver. THE RENIN ANGIOTENSIN SYSTEM IN CANCER, LUNG, LIVER AND INFECTIOUS DISEASES 2023:179-197. [DOI: 10.1007/978-3-031-23621-1_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2023]
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Godoy-Lugo JA, Mendez DA, Rodriguez R, Nishiyama A, Nakano D, Soñanez-Organis JG, Ortiz RM. Improved lipogenesis gene expression in liver is associated with elevated plasma angiotensin 1-7 after AT1 receptor blockade in insulin-resistant OLETF rats. Mol Cell Endocrinol 2022; 555:111729. [PMID: 35921918 DOI: 10.1016/j.mce.2022.111729] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 07/18/2022] [Accepted: 07/21/2022] [Indexed: 11/19/2022]
Abstract
Increased angiotensin II (Ang II) signaling contributes to insulin resistance and liver steatosis. In addition to ameliorating hypertension, angiotensin receptor blockers (ARBs) improve lipid metabolism and hepatic steatosis, which are impaired with metabolic syndrome (MetS). Chronic blockade of the Ang II receptor type 1 (AT1) increases plasma angiotensin 1-7 (Ang 1-7), which mediates mechanisms counterregulatory to AT1 signaling. Elevated plasma Ang 1-7 is associated with decreased plasma triacylglycerol (TAG), cholesterol, glucose, and insulin; however, the benefits of RAS modulation to prevent non-alcoholic fatty liver disease (NAFLD) are not fully investigated. To better address the relationships among chronic ARB treatment, plasma Ang 1-7, and hepatic steatosis, three groups of 10-week-old-rats were studied: (1) untreated lean Long Evans Tokushima Otsuka (LETO), (2) untreated Otsuka Long Evans Tokushima Fatty (OLETF), and (3) OLETF + ARB (ARB; 10 mg olmesartan/kg/d × 6 weeks). Following overnight fasting, rats underwent an acute glucose load to better understand the dynamic metabolic responses during hepatic steatosis and early MetS. Tissues were collected at baseline (pre-load; T0) and 1 and 2 h post-glucose load. AT1 blockade increased plasma Ang 1-7 and decreased liver lipids, which was associated with decreased fatty acid transporter 5 (FATP5) and fatty acid synthase (FASN) expression. AT1 blockade decreased liver glucose and increased glucokinase (GCK) expression. These results demonstrate that during MetS, overactivation of AT1 promotes hepatic lipid deposition that is stimulated by an acute glucose load and lipogenesis genes, suggesting that the chronic hyperglycemia associated with MetS contributes to fatty liver pathologies via an AT1-mediated mechanism.
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Affiliation(s)
- Jose A Godoy-Lugo
- School of Natural Sciences, University of California, Merced, CA, USA.
| | - Dora A Mendez
- School of Natural Sciences, University of California, Merced, CA, USA
| | - Ruben Rodriguez
- School of Natural Sciences, University of California, Merced, CA, USA
| | - Akira Nishiyama
- Department of Pharmacology, Kagawa University Medical School, Kagawa, Japan
| | - Daisuke Nakano
- Department of Pharmacology, Kagawa University Medical School, Kagawa, Japan
| | - Jose G Soñanez-Organis
- Universidad de Sonora, Departamento de Ciencias Químico Biológicas y Agropecuarias, Navojoa, Sonora, Mexico
| | - Rudy M Ortiz
- School of Natural Sciences, University of California, Merced, CA, USA
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4
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Godoy-Lugo JA, Thorwald MA, Hui DY, Nishiyama A, Nakano D, Soñanez-Organis JG, Ortiz RM. Chronic angiotensin receptor activation promotes hepatic triacylglycerol accumulation during an acute glucose challenge in obese-insulin-resistant OLETF rats. Endocrine 2022; 75:92-107. [PMID: 34327606 PMCID: PMC8763929 DOI: 10.1007/s12020-021-02834-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 07/18/2021] [Indexed: 11/01/2022]
Abstract
PURPOSE Angiotensin receptor blockers (ARBs) can ameliorate metabolic syndrome (MetS)-associated dyslipidemia, hepatic steatosis, and glucose intolerance, suggesting that angiotensin receptor (AT1) over-activation contributes to impaired lipid and glucose metabolism, which is characteristic of MetS. The aim of this study was to evaluate changes in the lipid profile and proteins of fatty acid uptake, triacylglycerol (TAG) synthesis, and β-oxidation to better understand the links between AT1 overactivation and non-alcoholic fatty liver disease (NAFLD) during MetS. METHODS Four groups of 25-week-old-rats were used: (1) untreated LETO, (2) untreated OLETF, (3) OLETF + angiotensin receptor blocker (ARB; 10 mg olmesartan/kg/d × 8 weeks) and (4) OLETF ± ARB (MINUS; 10 mg olmesartan/kg/d × 4 weeks, then removed until dissection). To investigate the dynamic shifts in metabolism, animals were dissected after an oral glucose challenge (fasting, 3 and 6 h post-glucose). RESULTS Compared to OLETF, plasma total cholesterol and TAG remained unchanged in ARB. However, liver TAG was 55% lesser in ARB than OLETF, and remained lower throughout the challenge. Basal CD36 and ApoB were 28% and 29% lesser, respectively, in ARB than OLETF. PRDX6 abundance in ARB was 45% lesser than OLETF, and it negatively correlated with liver TAG in ARB. CONCLUSIONS Chronic blockade of AT1 protects the liver from TAG accumulation during glucose overload. This may be achieved by modulating NEFA uptake and increasing TAG export via ApoB. Our study highlights the contributions of AT1 signaling to impaired hepatic substrate metabolism and the detriments of a high-glucose load and its potential contribution to steatosis during MetS.
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Affiliation(s)
- Jose A Godoy-Lugo
- School of Natural Sciences, University of California, Merced, CA, USA.
| | - Max A Thorwald
- School of Natural Sciences, University of California, Merced, CA, USA
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA
| | - David Y Hui
- Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, OH, USA
| | - Akira Nishiyama
- Department of Pharmacology, Kagawa University Medical School, Kagawa, Japan
| | - Daisuke Nakano
- Department of Pharmacology, Kagawa University Medical School, Kagawa, Japan
| | - Jose G Soñanez-Organis
- Universidad de Sonora, Departamento de Ciencias Químico Biológicas y Agropecuarias, Navojoa, Sonora, Mexico
| | - Rudy M Ortiz
- School of Natural Sciences, University of California, Merced, CA, USA
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Rodriguez R, Lee AY, Godoy-Lugo JA, Martinez B, Ohsaki H, Nakano D, Parkes DG, Nishiyama A, Vázquez-Medina JP, Ortiz RM. Chronic AT 1 blockade improves hyperglycemia by decreasing adipocyte inflammation and decreasing hepatic PCK1 and G6PC1 expression in obese rats. Am J Physiol Endocrinol Metab 2021; 321:E714-E727. [PMID: 34658252 PMCID: PMC8782654 DOI: 10.1152/ajpendo.00584.2020] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 10/04/2021] [Accepted: 10/07/2021] [Indexed: 11/22/2022]
Abstract
Inappropriate activation of the renin-angiotensin system decreases glucose uptake in peripheral tissues. Chronic angiotensin receptor type 1 (AT1) blockade (ARB) increases glucose uptake in skeletal muscle and decreases the abundance of large adipocytes and macrophage infiltration in adipose. However, the contributions of each tissue to the improvement in hyperglycemia in response to AT1 blockade are not known. Therefore, we determined the static and dynamic responses of soleus muscle, liver, and adipose to an acute glucose challenge following the chronic blockade of AT1. We measured adipocyte morphology along with TNF-α expression, F4/80- and CD11c-positive cells in adipose and measured insulin receptor (IR) phosphorylation and AKT phosphorylation in soleus muscle, liver, and retroperitoneal fat before (T0), 60 (T60) and 120 (T120) min after an acute glucose challenge in the following groups of male rats: 1) Long-Evans Tokushima Otsuka (LETO; lean control; n = 5/time point), 2) obese Otsuka Long Evans Tokushima Fatty (OLETF; n = 7 or 8/time point), and 3) OLETF + ARB (ARB; 10 mg olmesartan/kg/day; n = 7 or 8/time point). AT1 blockade decreased adipocyte TNF-α expression and F4/80- and CD11c-positive cells. In retroperitoneal fat at T60, IR phosphorylation was 155% greater in ARB than in OLETF. Furthermore, in retroperitoneal fat AT1 blockade increased glucose transporter-4 (GLUT4) protein expression in ARB compared with OLETF. IR phosphorylation and AKT phosphorylation were not altered in the liver of OLETF, but AT1 blockade decreased hepatic Pck1 and G6pc1 mRNA expressions. Collectively, these results suggest that chronic AT1 blockade improves obesity-associated hyperglycemia in OLETF rats by improving adipocyte function and by decreasing hepatic glucose production via gluconeogenesis.NEW & NOTEWORTHY Inappropriate activation of the renin-angiotensin system increases adipocyte inflammation contributing to the impairment in adipocyte function and increases hepatic Pck1 and G6pc1 mRNA expression in response to a glucose challenge. Ultimately, these effects may contribute to the development of glucose intolerance.
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Affiliation(s)
- Ruben Rodriguez
- Department of Molecular & Cellular Biology, University of California, Merced, California
| | - Andrew Y Lee
- Department of Molecular & Cellular Biology, University of California, Merced, California
| | - Jose A Godoy-Lugo
- Department of Molecular & Cellular Biology, University of California, Merced, California
| | - Bridget Martinez
- Department of Molecular & Cellular Biology, University of California, Merced, California
| | - Hiroyuki Ohsaki
- Department of Medical Biophysics, Kobe University Graduate School of Health Sciences, Kobe, Japan
| | - Daisuke Nakano
- Department of Pharmacology, Kagawa University Medical School, Kagawa, Japan
| | | | - Akira Nishiyama
- Department of Pharmacology, Kagawa University Medical School, Kagawa, Japan
| | | | - Rudy M Ortiz
- Department of Molecular & Cellular Biology, University of California, Merced, California
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Yang M, Ma X, Xuan X, Deng H, Chen Q, Yuan L. Liraglutide Attenuates Non-Alcoholic Fatty Liver Disease in Mice by Regulating the Local Renin-Angiotensin System. Front Pharmacol 2020; 11:432. [PMID: 32322207 PMCID: PMC7156971 DOI: 10.3389/fphar.2020.00432] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Accepted: 03/20/2020] [Indexed: 12/14/2022] Open
Abstract
The renin-angiotensin system (RAS) is involved in the pathogenesis of non-alcoholic fatty liver disease (NAFLD) and represents a potential therapeutic target for NAFLD. Glucagon-like peptide-1 (GLP-1) signaling has been shown to regulate the RAS within various local tissues. In this study, we aimed to investigate the functional relationship between GLP-1 and the local RAS in the liver during NAFLD. Wild-type and ACE2 knockout mice were used to establish a high-fat-induced NAFLD model. After the mice were treated with liraglutide (a GLP-1 analogue) for 4 weeks, the key RAS component genes were up-regulated in the liver of NAFLD mice. Liraglutide treatment regulated the RAS balance, preventing a reduction in fatty acid oxidation gene expression and increasing gluconeogenesis and the expression of inflammation-related genes caused by NAFLD, which were impaired in ACE2 knockout mice. Liraglutide-treated HepG2 cells exhibited activation of the ACE2/Ang1-7/Mas axis, increased fatty acid oxidation gene expression, and decreased inflammation, which could be reversed by A779 and AngII. These results indicate that the local RAS in the liver becomes overactivated in response to NAFLD. Moreover, ACE2 knockout increases the severity of liver steatosis. Liraglutide has a negative and antagonistic effect on the ACE/AngII/AT1R axis, a positive impact on the ACE2/Ang1-7/Mas axis, and is mediated through the PI3K/AKT pathway. This may represent a potential new mechanism by which liraglutide improves NAFLD.
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Affiliation(s)
- Mengying Yang
- Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiaoyi Ma
- Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiuping Xuan
- Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Hongjun Deng
- Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Qi Chen
- Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Li Yuan
- Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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Rodriguez R, Escobedo B, Lee AY, Thorwald M, Godoy-Lugo JA, Nakano D, Nishiyama A, Parkes DG, Ortiz RM. Simultaneous angiotensin receptor blockade and glucagon-like peptide-1 receptor activation ameliorate albuminuria in obese insulin-resistant rats. Clin Exp Pharmacol Physiol 2019; 47:422-431. [PMID: 31675433 DOI: 10.1111/1440-1681.13206] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 10/21/2019] [Accepted: 10/30/2019] [Indexed: 01/13/2023]
Abstract
Insulin resistance increases renal oxidant production by upregulating NADPH oxidase 4 (Nox4) expression contributing to oxidative damage and ultimately albuminuria. Inhibition of the renin-angiotensin system (RAS) and activation of glucagon-like peptide-1 (GLP-1) receptor signalling may reverse this effect. However, whether angiotensin receptor type 1 (AT1) blockade and GLP-1 receptor activation improve oxidative damage and albuminuria through different mechanisms is not known. Using insulin-resistant Otsuka Long-Evans Tokushima Fatty (OLETF) rats, we tested the hypothesis that simultaneous blockade of AT1 and activation of GLP-1r additively decrease oxidative damage and urinary albumin excretion (Ualb V) in the following groups: (a) untreated, lean LETO (n = 7), (b) untreated, obese OLETF (n = 9), (c) OLETF + angiotensin receptor blocker (ARB; 10 mg olmesartan/kg/d; n = 9), (d) OLETF + GLP-1 mimetic (EXE; 10 µg exenatide/kg/d; n = 7) and (e) OLETF + ARB +exenatide (Combo; n = 6). Mean kidney Nox4 protein expression and nitrotyrosine (NT) levels were 30% and 46% greater, respectively, in OLETF compared with LETO. Conversely, Nox4 protein expression and NT were reduced to LETO levels in ARB and EXE, and Combo reduced Nox4, NT and 4-hydroxy-2-nonenal levels by 21%, 27% and 27%, respectively. At baseline, Ualb V was nearly double in OLETF compared with LETO and increased to nearly 10-fold greater levels by the end of the study. Whereas ARB (45%) and EXE (55%) individually reduced Ualb V, the combination completely ameliorated the albuminuria. Collectively, these data suggest that AT1 blockade and GLP-1 receptor activation reduce renal oxidative damage similarly during insulin resistance, whereas targeting both signalling pathways provides added benefit in restoring and/or further ameliorating albuminuria in a model of diet-induced obesity.
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Affiliation(s)
- Ruben Rodriguez
- Department of Molecular & Cellular Biology, University of California Merced, Merced, CA, USA
| | - Benny Escobedo
- Department of Molecular & Cellular Biology, University of California Merced, Merced, CA, USA
| | - Andrew Y Lee
- Department of Molecular & Cellular Biology, University of California Merced, Merced, CA, USA
| | - Max Thorwald
- Department of Molecular & Cellular Biology, University of California Merced, Merced, CA, USA
| | - Jose A Godoy-Lugo
- Department of Molecular & Cellular Biology, University of California Merced, Merced, CA, USA
| | - Daisuke Nakano
- Department of Pharmacology, Kagawa University Medical School, Kagawa, Japan
| | - Akira Nishiyama
- Department of Pharmacology, Kagawa University Medical School, Kagawa, Japan
| | | | - Rudy M Ortiz
- Department of Molecular & Cellular Biology, University of California Merced, Merced, CA, USA
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Liu J, Li X, Lu Q, Ren D, Sun X, Rousselle T, Li J, Leng J. AMPK: a balancer of the renin-angiotensin system. Biosci Rep 2019; 39:BSR20181994. [PMID: 31413168 PMCID: PMC6722492 DOI: 10.1042/bsr20181994] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 07/24/2019] [Accepted: 08/12/2019] [Indexed: 02/07/2023] Open
Abstract
The renin-angiotensin system (RAS) is undisputedly well-studied as one of the oldest and most critical regulators for arterial blood pressure, fluid volume, as well as renal function. In recent studies, RAS has also been implicated in the development of obesity, diabetes, hyperlipidemia, and other diseases, and also involved in the regulation of several signaling pathways such as proliferation, apoptosis and autophagy, and insulin resistance. AMP-activated protein kinase (AMPK), an essential cellular energy sensor, has also been discovered to be involved in these diseases and cellular pathways. This would imply a connection between the RAS and AMPK. Therefore, this review serves to draw attention to the cross-talk between RAS and AMPK, then summering the most recent literature which highlights AMPK as a point of balance between physiological and pathological functions of the RAS.
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Affiliation(s)
- Jia Liu
- Department of Geriatrics, The First Hospital of Jilin University, Changchun 130021, China
- Department of Surgery, University of South Florida, Tampa, FL 33612, U.S.A
| | - Xuan Li
- Mississippi Center for Heart Research, Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS 39216, U.S.A
| | - Qingguo Lu
- Mississippi Center for Heart Research, Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS 39216, U.S.A
| | - Di Ren
- Department of Surgery, University of South Florida, Tampa, FL 33612, U.S.A
| | - Xiaodong Sun
- Mississippi Center for Heart Research, Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS 39216, U.S.A
| | - Thomas Rousselle
- Mississippi Center for Heart Research, Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS 39216, U.S.A
| | - Ji Li
- Department of Surgery, University of South Florida, Tampa, FL 33612, U.S.A
| | - Jiyan Leng
- Department of Geriatrics, The First Hospital of Jilin University, Changchun 130021, China
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Thorwald MA, Godoy-Lugo JA, Rodriguez GJ, Rodriguez MA, Jamal M, Kinoshita H, Nakano D, Nishiyama A, Forman HJ, Ortiz RM. Nrf2-related gene expression is impaired during a glucose challenge in type II diabetic rat hearts. Free Radic Biol Med 2019; 130:306-317. [PMID: 30316779 DOI: 10.1016/j.freeradbiomed.2018.10.405] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 09/21/2018] [Accepted: 10/03/2018] [Indexed: 12/25/2022]
Abstract
Diabetic hearts are susceptible to damage from inappropriate activation of the renin angiotensin system (RAS) and hyperglycemic events both of which contribute to increased oxidant production. Prolonged elevation of oxidants impairs mitochondrial enzyme function, further contributing to metabolic derangement. Nuclear factor erythriod-2-related factor 2 (Nrf2) induces antioxidant genes including those for glutathione (GSH) synthesis following translocation to the nucleus. We hypothesized that an acute elevation in glucose impairs Nrf2-related gene expression in diabetic hearts, while AT1 antagonism would aid in Nrf2-mediated antioxidant production and energy replenishment. We used four groups (n = 6-8/group) of 25-week-old rats: 1) LETO (lean strain-control), 2) type II diabetic OLETF, 3) OLETF + angiotensin receptor blocker (ARB; 10 mg olmesartan/kg/d × 8 wks), and 4) ARBM (4 weeks on ARB, 4 weeks off) to study the effects of acutely elevated glucose on cardiac mitochondrial function and Nrf2 signaling in the diabetic heart. Animals were gavaged with a glucose bolus (2 g/kg) and groups were dissected at T0, T180, and T360 minutes. Nrf2 mRNA was 32% lower in OLETF rats compared to LETO and remained suppressed in response to glucose. LETO Nrf2 mRNA increased 25% at T360 in response to glucose while no changes were observed in diabetic hearts. GCLC and GCLM mRNA decreased in diabetic hearts 33% and 44% respectively and remained suppressed in response to glucose while ARB treatment increased GCLM transcripts 90% at T180. These data illustrate that during T2DM and in response to glucose, cardiac Nrf2's adaptive response to environmental stressors such as glucose is impaired in diabetic hearts and that ARB treatment may aid Nrf2's impaired dynamic response.
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Affiliation(s)
- Max A Thorwald
- School of Natural Sciences, University of California, Merced, United States; Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, United States.
| | - Jose A Godoy-Lugo
- School of Natural Sciences, University of California, Merced, United States
| | - Gema J Rodriguez
- School of Natural Sciences, University of California, Merced, United States
| | | | - Mostofa Jamal
- Department of Forensic Medicine, Kagawa University Medical School, Japan
| | - Hiroshi Kinoshita
- Department of Forensic Medicine, Kagawa University Medical School, Japan
| | - Daisuke Nakano
- Department of Pharmacology, Kagawa University Medical School, Kagawa, Japan
| | - Akira Nishiyama
- Department of Pharmacology, Kagawa University Medical School, Kagawa, Japan
| | - Henry J Forman
- School of Natural Sciences, University of California, Merced, United States; Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, United States
| | - Rudy M Ortiz
- School of Natural Sciences, University of California, Merced, United States
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Nishimura N, Kaji K, Kitade M, Aihara Y, Sato S, Seki K, Sawada Y, Takaya H, Okura Y, Kawaratani H, Moriya K, Namisaki T, Mitoro A, Yoshiji H. Acyclic retinoid and angiotensin-II receptor blocker exert a combined protective effect against diethylnitrosamine-induced hepatocarcinogenesis in diabetic OLETF rats. BMC Cancer 2018; 18:1164. [PMID: 30477453 PMCID: PMC6260898 DOI: 10.1186/s12885-018-5099-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2018] [Accepted: 11/15/2018] [Indexed: 02/07/2023] Open
Abstract
Background Insulin resistance (IR) is closely associated with the progression of hepatocellular carcinoma (HCC). Acyclic retinoid (ACR) targets retinoid X receptor α and reportedly prevents HCC recurrence in clinical practice. Angiotensin-II receptor blocker (ARB) can also inhibit experimental hepatocarcinogenesis and HCC development. These are reported to suppress IR-based hepatocarcinogenesis; however, limited data are available regarding the combined effects of both these agents. This study aimed to investigate the combined chemopreventive effect of ACR and ARB on liver tumorigenesis on rats with congenital diabetes. Methods Male diabetic Otsuka Long-Evans Tokushima Fatty (OLETF) and non-diabetic Long-Evans Tokushima Otsuka (LETO) rats underwent 70% partial hepatectomy following a single intraperitoneal injection of diethylnitrosamine to induce hepatocarcinogenesis and the administration of ACR (peretinoin, 40 mg/kg/day), ARB (losartan, 30 mg/kg/day), and a combination of ACR and ARB. Six weeks thereafter, we assessed the size and number of the pre-neoplastic lesions (PNL) as well as the altered angiogenesis, oxidative stress, and chronic inflammation in the liver. Moreover, we assessed the effects exerted by ACR and ARB on in vitro cell growth in human HCC cell lines and human umbilical vascular endothelial cells (HUVECs). Results OLETF rats showed increase in the size and number of PNLs compared to LETO rats. ACR suppressed the augmentation in size and number of PNLs in the OLETF rats with suppression of cell growth, intrahepatic angiogenesis, lipid peroxidation, oxidative DNA damage, and proinflammatory cytokine production. Combining ACR with ARB enhanced the tumor-suppressive effect and ameliorated intrahepatic angiogenesis, lipid peroxidation, and proinflammatory status; however, cell growth and oxidative DNA damage remained unchanged. IR-mimetic condition accelerated in vitro proliferative activity in human HCC cells, while ACR inhibited this proliferation with G0/G1 arrest and apoptosis. Furthermore, ACR and ARB significantly attenuated the HUVECs proliferation and tubular formation under the IR-mimetic condition, and a combination of both agents demonstrated greater inhibitory effects on HUVEC growth than each single treatment. Conclusions ACR and ARB exert a combined inhibitory effect against IR-based hepatocarcinogenesis by the inhibition of cell growth, intrahepatic angiogenesis, and oxidative stress. Thus, this combination therapy appears to hold potential as a chemopreventive treatment therapy against HCC. Electronic supplementary material The online version of this article (10.1186/s12885-018-5099-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Norihisa Nishimura
- Third Department of Internal Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8522, Japan
| | - Kosuke Kaji
- Third Department of Internal Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8522, Japan.
| | - Mitsuteru Kitade
- Third Department of Internal Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8522, Japan
| | - Yosuke Aihara
- Third Department of Internal Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8522, Japan
| | - Shinya Sato
- Third Department of Internal Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8522, Japan
| | - Kenichiro Seki
- Third Department of Internal Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8522, Japan
| | - Yasuhiko Sawada
- Third Department of Internal Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8522, Japan
| | - Hiroaki Takaya
- Third Department of Internal Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8522, Japan
| | - Yasushi Okura
- Third Department of Internal Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8522, Japan
| | - Hideto Kawaratani
- Third Department of Internal Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8522, Japan
| | - Kei Moriya
- Third Department of Internal Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8522, Japan
| | - Tadashi Namisaki
- Third Department of Internal Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8522, Japan
| | - Akira Mitoro
- Third Department of Internal Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8522, Japan
| | - Hitoshi Yoshiji
- Third Department of Internal Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8522, Japan
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11
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Rodriguez R, Lee A, Mathis KW, Broome HJ, Thorwald M, Martinez B, Nakano D, Nishiyama A, Ryan MJ, Ortiz RM. Angiotensin receptor and tumor necrosis factor-α activation contributes to glucose intolerance independent of systolic blood pressure in obese rats. Am J Physiol Renal Physiol 2018; 315:F1081-F1090. [PMID: 29993275 DOI: 10.1152/ajprenal.00156.2018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Pathological activation of the renin-angiotensin system and inflammation are associated with hypertension and the development of metabolic syndrome (MetS). The contributions of angiotensin receptor type 1 (AT1) activation, independent of blood pressure, and inflammation to glucose intolerance and renal damage are not well defined. Using a rat model of MetS, we hypothesized that the onset of glucose intolerance is primarily mediated by AT1 activation and inflammation independent of elevated systolic blood pressure (SBP). To address this hypothesis, we measured changes in SBP, adiposity, plasma glucose and triglyceride levels, and glucose tolerance in six groups of rats: 1) lean, strain control Long-Evans Tokushima Otsuka (LETO; n = 5), 2) obese Otsuka Long-Evans Tokushima Fatty (OLETF; n = 8), 3) OLETF + angiotensin receptor blocker (ARB; 10 mg olmesartan/kg; n = 8), 4) OLETF + tumor necrosis factor-α (TNF-α) inhibitor (ETAN; 1.25 mg etanercept/kg; n = 6), 5) OLETF + TNF-α inhibitor + angiotensin receptor blocker (ETAN+ARB; 1.25 mg etanercept/kg + 10 mg olmesartan/kg; n = 6), and 6) OLETF + calcium channel blocker (CCB; 5 mg amlodipine/kg; n = 7). ARB and ETAN+ARB were most effective at decreasing SBP in OLETF, and ETAN did not offer any additional reduction. Glucose tolerance improved in ARB, ETAN, and ETAN+ARB compared with OLETF, whereas CCB had no detectable effect. Furthermore, all treatments reduced adiposity, whereas ETAN alone normalized urinary albumin excretion. These results suggest that AT1 activation and inflammation are primary factors in the development of glucose intolerance in a setting of MetS and that the associated increase in SBP is primarily mediated by AT1 activation.
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Affiliation(s)
- Ruben Rodriguez
- Department of Molecular and Cellular Biology, University of California, Merced, California
| | - Andrew Lee
- Department of Molecular and Cellular Biology, University of California, Merced, California
| | - Keisa W Mathis
- Department of Physiology and Anatomy, University of North Texas Health Science Center , Fort Worth, Texas
| | - Hanna J Broome
- Department of Biological Sciences, Mississippi College , Clinton, Mississippi
| | - Max Thorwald
- Department of Molecular and Cellular Biology, University of California, Merced, California
| | - Bridget Martinez
- Department of Molecular and Cellular Biology, University of California, Merced, California.,School of Medicine, St. George's University , St. George's , Grenada.,Department of Physics and Engineering, Los Alamos National Laboratory , Los Alamos, New Mexico
| | - Daisuke Nakano
- Department of Pharmacology, Faculty of Medicine, Kagawa University , Takamatsu , Japan
| | - Akira Nishiyama
- Department of Pharmacology, Faculty of Medicine, Kagawa University , Takamatsu , Japan
| | - Michael J Ryan
- Department of Physiology and Biophysics, University of Mississippi Medical Center , Jackson, Mississippi.,G.V. (Sonny) Montgomery Veterans Affairs Medical Center , Jackson, Mississippi
| | - Rudy M Ortiz
- Department of Molecular and Cellular Biology, University of California, Merced, California
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12
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Rodriguez R, Minas JN, Vazquez-Medina JP, Nakano D, Parkes DG, Nishiyama A, Ortiz RM. Chronic AT1 blockade improves glucose homeostasis in obese OLETF rats. J Endocrinol 2018; 237:271-284. [PMID: 29643115 PMCID: PMC5945211 DOI: 10.1530/joe-17-0678] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 04/11/2018] [Indexed: 12/17/2022]
Abstract
Obesity is associated with the inappropriate activation of the renin-angiotensin system (RAS), which increases arterial pressure, impairs insulin secretion and decreases peripheral tissue insulin sensitivity. RAS blockade reverses these detriments; however, it is not clear whether the disease state of the organism and treatment duration determine the beneficial effects of RAS inhibition on insulin secretion and insulin sensitivity. Therefore, the objective of this study was to compare the benefits of acute vs chronic angiotensin receptor type 1 (AT1) blockade started after the onset of obesity, hyperglycemia and hypertension on pancreatic function and peripheral insulin resistance. We assessed adipocyte morphology, glucose intolerance, pancreatic redox balance and insulin secretion after 2 and 11 weeks of AT1 blockade in the following groups of rats: (1) untreated Long-Evans Tokushima Otsuka (lean control; n = 10), (2) untreated Otsuka Long-Evans Tokushima Fatty (OLETF; n = 12) and (3) OLETF + ARB (ARB; 10 mg olmesartan/kg/day by oral gavage; n = 12). Regardless of treatment duration, AT1 blockade decreased systolic blood pressure and fasting plasma triglycerides, whereas chronic AT1 blockade decreased fasting plasma glucose, glucose intolerance and the relative abundance of large adipocytes by 22, 36 and 70%, respectively. AT1 blockade, however, did not improve pancreatic oxidative stress or reverse impaired insulin secretion. Collectively, these data show that AT1 blockade after the onset of obesity, hyperglycemia and hypertension improves peripheral tissue insulin sensitivity, but cannot completely reverse the metabolic derangement characterized by impaired insulin secretion once it has been compromised.
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Affiliation(s)
- Ruben Rodriguez
- Department of Molecular & Cellular BiologyUniversity of California, Merced, California, USA
| | - Jacqueline N Minas
- Department of Molecular & Cellular BiologyUniversity of California, Merced, California, USA
| | | | - Daisuke Nakano
- Department of PharmacologyKagawa University Medical School, Kagawa, Japan
| | | | - Akira Nishiyama
- Department of PharmacologyKagawa University Medical School, Kagawa, Japan
| | - Rudy M Ortiz
- Department of Molecular & Cellular BiologyUniversity of California, Merced, California, USA
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13
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Castro VMFD, Melo ACD, Belo VS, Chaves VE. Effect of allopurinol and uric acid normalization on serum lipids hyperuricemic subjects: A systematic review with meta-analysis. Clin Biochem 2017; 50:1289-1297. [DOI: 10.1016/j.clinbiochem.2017.07.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2017] [Revised: 07/21/2017] [Accepted: 07/24/2017] [Indexed: 01/08/2023]
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14
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Vazquez-Anaya G, Martinez B, Soñanez-Organis JG, Nakano D, Nishiyama A, Ortiz RM. Exogenous thyroxine improves glucose intolerance in insulin-resistant rats. J Endocrinol 2017; 232:501-511. [PMID: 27980001 PMCID: PMC5419047 DOI: 10.1530/joe-16-0428] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 12/15/2016] [Indexed: 12/19/2022]
Abstract
Both hypothyroidism and hyperthyroidism are associated with glucose intolerance, calling into question the contribution of thyroid hormones (TH) on glucose regulation. TH analogues and derivatives may be effective treatment options for glucose intolerance and insulin resistance (IR), but their potential glucoregulatory effects during conditions of impaired metabolism are not well described. To assess the effects of thyroxine (T4) on glucose intolerance in a model of insulin resistance, an oral glucose tolerance test (oGTT) was performed on three groups of rats (n = 8): (1) lean, Long Evans Tokushima Otsuka (LETO), (2) obese, Otsuka Long Evans Tokushima Fatty (OLETF) and (3) OLETF + T4 (8.0 µg/100 g BM/day × 5 weeks). T4 attenuated glucose intolerance by 15% and decreased IR index (IRI) by 34% in T4-treated OLETF compared to untreated OLETF despite a 31% decrease in muscle Glut4 mRNA expression. T4 increased the mRNA expressions of muscle monocarboxylate transporter 10 (Mct10), deiodinase type 2 (Di2), sirtuin 1 (Sirt1) and uncoupling protein 2 (Ucp2) by 1.8-, 2.2-, 2.7- and 1.4-fold, respectively, compared to OLETF. Activation of AMP-activated protein kinase (AMPK) and insulin receptor were not significantly altered suggesting that the improvements in glucose intolerance and IR were independent of enhanced insulin-mediated signaling. The results suggest that T4 treatment increased the influx of T4 in skeletal muscle and, with an increase of DI2, increased the availability of the biologically active T3 to upregulate key factors such SIRT1 and UCP2 involved in cellular metabolism and glucose homeostasis.
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Affiliation(s)
| | - Bridget Martinez
- Department of Molecular & Cellular BiologyUniversity of California, Merced, California, USA
| | - José G Soñanez-Organis
- Division of Science and EngineeringDepartment of Chemical Biological and Agropecuary Sciences, University of Sonora, Navojoa, Sonora, Mexico
| | - Daisuke Nakano
- Department of PharmacologyFaculty of Medicine, Kagawa University, Kagawa, Japan
| | - Akira Nishiyama
- Department of PharmacologyFaculty of Medicine, Kagawa University, Kagawa, Japan
| | - Rudy M Ortiz
- Department of Molecular & Cellular BiologyUniversity of California, Merced, California, USA
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15
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Souza-Mello V. Hepatic structural enhancement and insulin resistance amelioration due to AT1 receptor blockade. World J Hepatol 2017; 9:74-79. [PMID: 28144388 PMCID: PMC5241531 DOI: 10.4254/wjh.v9.i2.74] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2016] [Revised: 10/18/2016] [Accepted: 11/22/2016] [Indexed: 02/06/2023] Open
Abstract
Over the last decade, the role of renin-angiotensin system (RAS) on the development of obesity and its comorbidities has been extensively addressed. Both circulating and local RAS components are up-regulated in obesity and involved in non-alcoholic fatty liver disease onset. Pharmacological manipulations of RAS are viable strategies to tackle metabolic impairments caused by the excessive body fat mass. Renin inhibitors rescue insulin resistance, but do not have marked effects on hepatic steatosis. However, angiotensin-converting enzyme inhibitors and angiotensin receptor blockers (ARB) yield beneficial hepatic remodeling. ARBs elicit body mass loss and normalize insulin levels, tackling insulin resistance. Also, this drug class increases adiponectin levels, besides countering interleukin-6, tumoral necrosis factor-alpha, and transforming growth factor-beta 1. The latter is essential to prevent from liver fibrosis. When conjugated with peroxisome proliferator-activated receptor (PPAR)-alpha activation, ARB fully rescues fatty liver. These effects might be orchestrated by an indirect up-regulation of MAS receptor due to angiotensin II receptor type 1 (AT1R) blockade. These associations of ARB with PPAR activation and ACE2-angiotensin (ANG) (1-7)-MAS receptor axis deserve a better understanding. This editorial provides a brief overview of the current knowledge regarding AT1R blockade effects on sensitivity to insulin and hepatic structural alterations as well as the intersections of AT1R blockade with peroxisome proliferator-activated receptor activation and ACE2-ANG (1-7) - MAS receptor axis.
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16
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CD36/Sirtuin 1 Axis Impairment Contributes to Hepatic Steatosis in ACE2-Deficient Mice. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2016; 2016:6487509. [PMID: 28101297 PMCID: PMC5215286 DOI: 10.1155/2016/6487509] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/09/2016] [Revised: 10/10/2016] [Accepted: 10/19/2016] [Indexed: 02/07/2023]
Abstract
Background and Aims. Angiotensin converting enzyme 2 (ACE2) is an important component of the renin-angiotensin system. Since angiotensin peptides have been shown to be involved in hepatic steatosis, we aimed to evaluate the hepatic lipid profile in ACE2-deficient (ACE2-/y) mice. Methods. Male C57BL/6 and ACE2-/y mice were analyzed at the age of 3 and 6 months for alterations in the lipid profiles of plasma, faeces, and liver and for hepatic steatosis. Results. ACE2-/y mice showed lower body weight and white adipose tissue at all ages investigated. Moreover, these mice had lower levels of cholesterol, triglycerides, and nonesterified fatty acids in plasma. Strikingly, ACE2-/y mice showed high deposition of lipids in the liver. Expression of CD36, a protein involved in the uptake of triglycerides in liver, was increased in ACE2-/y mice. Concurrently, these mice exhibited an increase in hepatic oxidative stress, evidenced by increased lipid peroxidation and expression of uncoupling protein 2, and downregulation of sirtuin 1. ACE2-/y mice also showed impairments in glucose metabolism and insulin signaling in the liver. Conclusions. Deletion of ACE2 causes CD36/sirtuin 1 axis impairment and thereby interferes with lipid homeostasis, leading to lipodystrophy and steatosis.
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17
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Mitochondrial Dysfunction Contributes to Hypertensive Target Organ Damage: Lessons from an Animal Model of Human Disease. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2016; 2016:1067801. [PMID: 27594970 PMCID: PMC4993945 DOI: 10.1155/2016/1067801] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 07/06/2016] [Accepted: 07/13/2016] [Indexed: 12/18/2022]
Abstract
Mechanisms underlying hypertensive target organ damage (TOD) are not completely understood. The pathophysiological role of mitochondrial oxidative stress, resulting from mitochondrial dysfunction, in development of TOD is unclear. The stroke-prone spontaneously hypertensive rat (SHRSP) is a suitable model of human hypertension and of its vascular consequences. Pathogenesis of TOD in SHRSP is multifactorial, being determined by high blood pressure levels, high salt/low potassium diet, and genetic factors. Accumulating evidence points to a key role of mitochondrial dysfunction in increased susceptibility to TOD development of SHRSP. Mitochondrial abnormalities were described in both heart and brain of SHRSP. Pharmacological compounds able to protect mitochondrial function exerted a significant protective effect on TOD development, independently of blood pressure levels. Through our research efforts, we discovered that two genes encoding mitochondrial proteins, one (Ndufc2) involved in OXPHOS complex I assembly and activity and the second one (UCP2) involved in clearance of mitochondrial ROS, are responsible, when dysregulated, for vascular damage in SHRSP. The suitability of SHRSP as a model of human disease represents a promising background for future translation of the experimental findings to human hypertension. Novel therapeutic strategies toward mitochondrial molecular targets may become a valuable tool for prevention and treatment of TOD in human hypertension.
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18
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Martinez B, Soñanez-Organis JG, Viscarra JA, Jaques JT, MacKenzie DS, Crocker DE, Ortiz RM. Glucose delays the insulin-induced increase in thyroid hormone-mediated signaling in adipose of prolong-fasted elephant seal pups. Am J Physiol Regul Integr Comp Physiol 2016; 310:R502-12. [PMID: 26739649 DOI: 10.1152/ajpregu.00054.2015] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 01/04/2016] [Indexed: 12/14/2022]
Abstract
Prolonged food deprivation in mammals typically reduces glucose, insulin, and thyroid hormone (TH) concentrations, as well as tissue deiodinase (DI) content and activity, which, collectively, suppress metabolism. However, in elephant seal pups, prolonged fasting does not suppress TH levels; it is associated with upregulation of adipose TH-mediated cellular mechanisms and adipose-specific insulin resistance. The functional relevance of this apparent paradox and the effects of glucose and insulin on TH-mediated signaling in an insulin-resistant tissue are not well defined. To address our hypothesis that insulin increases adipose TH signaling in pups during extended fasting, we assessed the changes in TH-associated genes in response to an insulin infusion in early- and late-fasted pups. In late fasting, insulin increased DI1, DI2, and THrβ-1 mRNA expression by 566%, 44%, and 267% at 60 min postinfusion, respectively, with levels decreasing by 120 min. Additionally, we performed a glucose challenge in late-fasted pups to differentiate between insulin- and glucose-mediated effects on TH signaling. In contrast to the insulin-induced effects, glucose infusion did not increase the expressions of DI1, DI2, and THrβ-1 until 120 min, suggesting that glucose delays the onset of the insulin-induced effects. The data also suggest that fasting duration increases the sensitivity of adipose TH-mediated mechanisms to insulin, some of which may be mediated by increased glucose. These responses appear to be unique among mammals and to have evolved in elephant seals to facilitate their adaptation to tolerate an extreme physiological condition.
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Affiliation(s)
- Bridget Martinez
- Department of Molecular & Cellular Biology, University of California, Merced, California;
| | - José G Soñanez-Organis
- Departamento de Ciencias Químico Biológicas y Agropecuarias, Universidad de Sonora, Navojoa, Sonora, México
| | - Jose A Viscarra
- Department of Molecular & Cellular Biology, University of California, Merced, California
| | - John T Jaques
- Veterinary Medical Diagnostic Laboratory, Texas A&M University, College Station, Texas
| | - Duncan S MacKenzie
- Department of Biology, Texas A&M University, College Station, Texas; and
| | - Daniel E Crocker
- Department of Biology, Sonoma State University, Rohnert Park, California
| | - Rudy M Ortiz
- Department of Molecular & Cellular Biology, University of California, Merced, California
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19
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Martinez B, Soñanez-Organis JG, Vázquez-Medina JP, Viscarra JA, MacKenzie DS, Crocker DE, Ortiz RM. Prolonged food deprivation increases mRNA expression of deiodinase 1 and 2, and thyroid hormone receptor β-1 in a fasting-adapted mammal. J Exp Biol 2013; 216:4647-54. [PMID: 24307712 PMCID: PMC3851149 DOI: 10.1242/jeb.085290] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Accepted: 09/04/2013] [Indexed: 12/21/2022]
Abstract
Food deprivation in mammals is typically associated with reduced thyroid hormone (TH) concentrations and deiodinase content and activity to suppress metabolism. However, in prolonged-fasted, metabolically active elephant seal pups, TH levels are maintained, if not elevated. The functional relevance of this apparent paradox is unknown and demonstrates variability in the regulation of TH levels, metabolism and function in food-deprived mammals. To address our hypothesis that cellular TH-mediated activity is upregulated with fasting duration, we quantified the mRNA expression and protein content of adipose and muscle deiodinase type I (DI1) and type II (DI2), and TH receptor beta-1 (THrβ-1) after 1, 3 and 7 weeks of fasting in northern elephant seal pups (N=5-7 per week). Fasting did not decrease the concentrations of plasma thyroid stimulating hormone, total triiodothyronine (tT3), free T3, total thyroxine (tT4) or free T4, suggesting that the hypothalamic-pituitary-thyroid axis is not suppressed, but rather maintained during fasting. Mean mRNA expression of adipose DI1 and DI2 increased threefold and fourfold, respectively, and 20- and 30-fold, respectively, in muscle. With the exception of adipose DI1, protein expression of adipose DI2 and muscle DI1 and DI2 increased twofold to fourfold. Fasting also increased adipose (fivefold) and muscle (fourfold) THrβ-1 mRNA expression, suggesting that the mechanisms mediating cellular TH activity are upregulated with prolonged fasting. The data demonstrate a unique, atypical mechanism of TH activity and regulation in mammals adapted to prolonged food deprivation in which the potential responsiveness of peripheral tissues and cellular TH activity are increased, which may contribute to their lipid-based metabolism.
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Affiliation(s)
- Bridget Martinez
- Department of Molecular and Cellular Biology, University of California, Merced, 5200 North Lake Road, Merced, CA 95343, USA
| | - José G. Soñanez-Organis
- Department of Molecular and Cellular Biology, University of California, Merced, 5200 North Lake Road, Merced, CA 95343, USA
| | - José Pablo Vázquez-Medina
- Department of Molecular and Cellular Biology, University of California, Merced, 5200 North Lake Road, Merced, CA 95343, USA
| | - Jose A. Viscarra
- Department of Molecular and Cellular Biology, University of California, Merced, 5200 North Lake Road, Merced, CA 95343, USA
| | - Duncan S. MacKenzie
- Department of Biology, Texas A&M University, College Station, TX 77843-3258, USA
| | - Daniel E. Crocker
- Department of Biology, Sonoma State University, Rohnert Park, CA 94928, USA
| | - Rudy M. Ortiz
- Department of Molecular and Cellular Biology, University of California, Merced, 5200 North Lake Road, Merced, CA 95343, USA
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20
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Abstract
Based on mosaic theory, hypertension is a multifactorial disorder that develops because of genetic, environmental, anatomical, adaptive neural, endocrine, humoral, and hemodynamic factors. It has been recently proposed that oxidative stress may contribute to all of these factors and production of reactive oxygen species (ROS) play an important role in the development of hypertension. Previous studies focusing on the role of vascular NADPH oxidases provided strong support of this concept. Although mitochondria represent one of the most significant sources of cellular ROS generation, the regulation of mitochondrial ROS generation in the cardiovascular system and its pathophysiological role in hypertension are much less understood. In this review, the role of mitochondrial oxidative stress in the pathophysiology of hypertension and cross talk between angiotensin II signaling, pathways involved in mechanotransduction, NADPH oxidases, and mitochondria-derived ROS are considered. The possible benefits of therapeutic strategies that have the potential to attenuate mitochondrial oxidative stress for the prevention/treatment of hypertension are also discussed.
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Affiliation(s)
- Sergey I Dikalov
- Division of Clinical Pharmacology, Free Radicals in Medicine Core, Vanderbilt University Medical Center, Nashville, Tennessee; and
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21
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Viscarra JA, Rodriguez R, Vazquez-Medina JP, Lee A, Tift MS, Tavoni SK, Crocker DE, Ortiz RM. Insulin and GLP-1 infusions demonstrate the onset of adipose-specific insulin resistance in a large fasting mammal: potential glucogenic role for GLP-1. Physiol Rep 2013; 1:e00023. [PMID: 23997935 PMCID: PMC3755502 DOI: 10.1002/phy2.23] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Prolonged food deprivation increases lipid oxidation and utilization, which may contribute to the onset of the insulin resistance associated with fasting. Because insulin resistance promotes the preservation of glucose and oxidation of fat, it has been suggested to be an adaptive response to food deprivation. However, fasting mammals exhibit hypoinsulinemia, suggesting that the insulin resistance-like conditions they experience may actually result from reduced pancreatic sensitivity to glucose/capacity to secrete insulin. To determine whether fasting results in insulin resistance or in pancreatic dysfunction, we infused early- and late-fasted seals (naturally adapted to prolonged fasting) with insulin (0.065 U/kg), and a separate group of late-fasted seals with low (10 pmol/L per kg) or high (100 pmol/L per kg) dosages of glucagon-like peptide-1 (GLP-1) immediately following a glucose bolus (0.5 g/kg), and measured the systemic and cellular responses. Because GLP-1 facilitates glucose-stimulated insulin secretion, these infusions provide a method to assess pancreatic insulin-secreting capacity. Insulin infusions increased the phosphorylation of insulin receptor and Akt in adipose and muscle of early- and late-fasted seals; however, the timing of the signaling response was blunted in adipose of late-fasted seals. Despite the dose-dependent increases in insulin and increased glucose clearance (high dose), both GLP-1 dosages produced increases in plasma cortisol and glucagon, which may have contributed to the glucogenic role of GLP-1. Results suggest that fasting induces adipose-specific insulin resistance in elephant seal pups, while maintaining skeletal muscle insulin sensitivity, and therefore suggests that the onset of insulin resistance in fasting mammals is an evolved response to cope with prolonged food deprivation.
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Affiliation(s)
- Jose A Viscarra
- School of Natural Sciences, University of California, Merced
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22
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Vázquez-Medina JP, Popovich I, Thorwald MA, Viscarra JA, Rodriguez R, Sonanez-Organis JG, Lam L, Peti-Peterdi J, Nakano D, Nishiyama A, Ortiz RM. Angiotensin receptor-mediated oxidative stress is associated with impaired cardiac redox signaling and mitochondrial function in insulin-resistant rats. Am J Physiol Heart Circ Physiol 2013; 305:H599-607. [PMID: 23771688 DOI: 10.1152/ajpheart.00101.2013] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Activation of angiotensin receptor type 1 (AT1) contributes to NADPH oxidase (Nox)-derived oxidative stress during metabolic syndrome. However, the specific role of AT1 in modulating redox signaling, mitochondrial function, and oxidative stress in the heart remains more elusive. To test the hypothesis that AT1 activation increases oxidative stress while impairing redox signaling and mitochondrial function in the heart during diet-induced insulin resistance in obese animals, Otsuka Long Evans Tokushima Fatty (OLETF) rats (n = 8/group) were treated with the AT1 blocker (ARB) olmesartan for 6 wk. Cardiac Nox2 protein expression increased 40% in OLETF compared with age-matched, lean, strain-control Long Evans Tokushima Otsuka (LETO) rats, while mRNA and protein expression of the H₂O₂-producing Nox4 increased 40-100%. ARB treatment prevented the increase in Nox2 without altering Nox4. ARB treatment also normalized the increased levels of protein and lipid oxidation (nitrotyrosine, 4-hydroxynonenal) and increased the redox-sensitive transcription factor Nrf2 by 30% and the activity of antioxidant enzymes (SOD, catalase, GPx) by 50-70%. Citrate synthase (CS) and succinate dehydrogenase (SDH) activities decreased 60-70%, whereas cardiac succinate levels decreased 35% in OLETF compared with LETO, suggesting that mitochondrial function in the heart is impaired during obesity-induced insulin resistance. ARB treatment normalized CS and SDH activities, as well as succinate levels, while increasing AMPK and normalizing Akt, suggesting that AT1 activation also impairs cellular metabolism in the diabetic heart. These data suggest that the cardiovascular complications associated with metabolic syndrome may result from AT1 receptor-mediated Nox2 activation leading to impaired redox signaling, mitochondrial activity, and dysregulation of cellular metabolism in the heart.
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Affiliation(s)
- José Pablo Vázquez-Medina
- Department of Molecular and Cellular Biology, School of Natural Sciences, University of California Merced, Merced, California
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