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Habibi J, Aroor AR, Das NA, Manrique-Acevedo CM, Johnson MS, Hayden MR, Nistala R, Wiedmeyer C, Chandrasekar B, DeMarco VG. The combination of a neprilysin inhibitor (sacubitril) and angiotensin-II receptor blocker (valsartan) attenuates glomerular and tubular injury in the Zucker Obese rat. Cardiovasc Diabetol 2019; 18:40. [PMID: 30909895 PMCID: PMC6432760 DOI: 10.1186/s12933-019-0847-8] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 03/18/2019] [Indexed: 02/08/2023] Open
Abstract
OBJECTIVE Diabetic nephropathy (DN) is characterized by glomerular and tubulointerstitial injury, proteinuria and remodeling. Here we examined whether the combination of an inhibitor of neprilysin (sacubitril), a natriuretic peptide-degrading enzyme, and an angiotensin II type 1 receptor blocker (valsartan), suppresses renal injury in a pre-clinical model of early DN more effectively than valsartan monotherapy. METHODS Sixty-four male Zucker Obese rats (ZO) at 16 weeks of age were distributed into 4 different groups: Group 1: saline control (ZOC); Group 2: sacubitril/valsartan (sac/val) (68 mg kg-1 day-1; ZOSV); and Group 3: valsartan (val) (31 mg kg-1 day-1; ZOV). Group 4 received hydralazine, an anti-hypertensive drug (30 mg kg-1 day-1, ZOH). Six Zucker Lean (ZL) rats received saline (Group 5) and served as lean controls (ZLC). Drugs were administered daily for 10 weeks by oral gavage. RESULTS Mean arterial pressure (MAP) increased in ZOC (+ 28%), but not in ZOSV (- 4.2%), ZOV (- 3.9%) or ZOH (- 3.7%), during the 10 week-study period. ZOC were mildly hyperglycemic, hyperinsulinemic and hypercholesterolemic. ZOC exhibited proteinuria, hyperfiltration, elevated renal resistivity index (RRI), glomerular mesangial expansion and podocyte foot process flattening and effacement, reduced nephrin and podocin expression, tubulointerstitial and periarterial fibrosis, increased NOX2, NOX4 and AT1R expression, glomerular and tubular nitroso-oxidative stress, with associated increases in urinary markers of tubular injury. None of the drugs reduced fasting glucose or HbA1c. Hypercholesterolemia was reduced in ZOSV (- 43%) and ZOV (- 34%) (p < 0.05), but not in ZOH (- 13%) (ZOSV > ZOV > ZOH). Proteinuria was ameliorated in ZOSV (- 47%; p < 0.05) and ZOV (- 30%; p > 0.05), but was exacerbated in ZOH (+ 28%; p > 0.05) (ZOSV > ZOV > ZOH). Compared to ZOC, hyperfiltration was improved in ZOSV (p < 0.05 vs ZOC), but not in ZOV or ZOH. None of the drugs improved RRI. Mesangial expansion was reduced by all 3 treatments (ZOV > ZOSV > ZOH). Importantly, sac/val was more effective in improving podocyte and tubular mitochondrial ultrastructure than val or hydralazine (ZOSV > ZOV > ZOH) and this was associated with increases in nephrin and podocin gene expression in ZOSV (p < 0.05), but not ZOV or ZOH. Periarterial and tubulointerstitial fibrosis and nitroso-oxidative stress were reduced in all 3 treatment groups to a similar extent. Of the eight urinary proximal tubule cell injury markers examined, five were elevated in ZOC (p < 0.05). Clusterin and KIM-1 were reduced in ZOSV (p < 0.05), clusterin alone was reduced in ZOV and no markers were reduced in ZOH (ZOSV > ZOV > ZOH). CONCLUSIONS Compared to val monotherapy, sac/val was more effective in reducing proteinuria, renal ultrastructure and tubular injury in a clinically relevant animal model of early DN. More importantly, these renoprotective effects were independent of improvements in blood pressure, glycemia and nitroso-oxidative stress. These novel findings warrant future clinical investigations designed to test whether sac/val may offer renoprotection in the setting of DN.
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Affiliation(s)
- Javad Habibi
- Diabetes and Cardiovascular Center, University of Missouri School of Medicine, Columbia, MO, USA.,Division of Endocrinology and Metabolism, Department of Medicine, University of Missouri-Columbia School of Medicine, D110, DC043.0, One Hospital Dr, Columbia, MO, 65212, USA.,Research Service, Harry S. Truman Memorial Veterans Hospital, Columbia, MO, USA
| | - Annayya R Aroor
- Diabetes and Cardiovascular Center, University of Missouri School of Medicine, Columbia, MO, USA.,Division of Endocrinology and Metabolism, Department of Medicine, University of Missouri-Columbia School of Medicine, D110, DC043.0, One Hospital Dr, Columbia, MO, 65212, USA.,Research Service, Harry S. Truman Memorial Veterans Hospital, Columbia, MO, USA
| | - Nitin A Das
- Cardiothoracic Surgery, University of Texas Health Science Center, San Antonio, TX, USA
| | - Camila M Manrique-Acevedo
- Diabetes and Cardiovascular Center, University of Missouri School of Medicine, Columbia, MO, USA.,Division of Endocrinology and Metabolism, Department of Medicine, University of Missouri-Columbia School of Medicine, D110, DC043.0, One Hospital Dr, Columbia, MO, 65212, USA.,Research Service, Harry S. Truman Memorial Veterans Hospital, Columbia, MO, USA
| | - Megan S Johnson
- Department of Obstetrics, Gynecology and Women's Health, University of Missouri, Columbia, MO, USA
| | - Melvin R Hayden
- Diabetes and Cardiovascular Center, University of Missouri School of Medicine, Columbia, MO, USA.,Division of Endocrinology and Metabolism, Department of Medicine, University of Missouri-Columbia School of Medicine, D110, DC043.0, One Hospital Dr, Columbia, MO, 65212, USA
| | - Ravi Nistala
- Research Service, Harry S. Truman Memorial Veterans Hospital, Columbia, MO, USA.,Division of Nephrology, Department of Medicine, University of Missouri, Columbia, MO, USA
| | - Charles Wiedmeyer
- College of Veterinary Medicine, University of Missouri, Columbia, MO, USA
| | - Bysani Chandrasekar
- Research Service, Harry S. Truman Memorial Veterans Hospital, Columbia, MO, USA.,Division of Cardiology, Department of Medicine, University of Missour, Columbia, MO, USA.,Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, USA
| | - Vincent G DeMarco
- Diabetes and Cardiovascular Center, University of Missouri School of Medicine, Columbia, MO, USA. .,Division of Endocrinology and Metabolism, Department of Medicine, University of Missouri-Columbia School of Medicine, D110, DC043.0, One Hospital Dr, Columbia, MO, 65212, USA. .,Research Service, Harry S. Truman Memorial Veterans Hospital, Columbia, MO, USA. .,Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, USA.
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Reduced Susceptibility to Sugar-Induced Metabolic Derangements and Impairments of Myocardial Redox Signaling in Mice Chronically Fed with D-Tagatose when Compared to Fructose. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2018; 2018:5042428. [PMID: 30327714 PMCID: PMC6169220 DOI: 10.1155/2018/5042428] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 08/12/2018] [Indexed: 01/03/2023]
Abstract
Background D-tagatose is an isomer of fructose and is ~90% as sweet as sucrose with less caloric value. Nowadays, D-tagatose is used as a nutritive or low-calorie sweetener. Despite clinical findings suggesting that D-tagatose could be beneficial in subjects with type 2 diabetes, there are no experimental data comparing D-tagatose with fructose, in terms of metabolic derangements and related molecular mechanisms evoked by chronic exposure to these two monosaccharides. Materials and methods C57Bl/6j mice were fed with a control diet plus water (CD), a control diet plus 30% fructose syrup (L-Fr), a 30% fructose solid diet plus water (S-Fr), a control diet plus 30% D-tagatose syrup (L-Tg), or a 30% D-tagatose solid diet plus water (S-Tg), during 24 weeks. Results Both solid and liquid fructose feeding led to increased body weight, abnormal systemic glucose homeostasis, and an altered lipid profile. These effects were associated with vigorous increase in oxidative markers. None of these metabolic abnormalities were detected when mice were fed with both the solid and liquid D-tagatose diets, either at the systemic or at the local level. Interestingly, both fructose formulations led to significant Advanced Glycation End Products (AGEs) accumulation in mouse hearts, as well as a robust increase in both myocardial AGE receptor (RAGE) expression and NF-κB activation. In contrast, no toxicological effects were shown in hearts of mice chronically exposed to liquid or solid D-tagatose. Conclusion Our results clearly suggest that chronic overconsumption of D-tagatose in both formulations, liquid or solid, does not exert the same deleterious metabolic derangements evoked by fructose administration, due to differences in carbohydrate interference with selective proinflammatory and oxidative stress cascades.
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Francisqueti FV, Nascimento AF, Minatel IO, Dias MC, Luvizotto RDAM, Berchieri-Ronchi C, Ferreira ALA, Corrêa CR. Metabolic syndrome and inflammation in adipose tissue occur at different times in animals submitted to a high-sugar/fat diet. J Nutr Sci 2017; 6:e41. [PMID: 29152245 PMCID: PMC5672321 DOI: 10.1017/jns.2017.42] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 05/23/2017] [Accepted: 06/29/2017] [Indexed: 12/16/2022] Open
Abstract
Obesity is associated with low-grade inflammation, triggered in adipose tissue, which may occur due to an excess of SFA from the diet that can be recognised by Toll-like receptor-4. This condition is involved in the development of components of the metabolic syndrome associated with obesity, especially insulin resistance. The aim of the study was to evaluate the manifestation of the metabolic syndrome and adipose tissue inflammation as a function of the period of time in which rats were submitted to a high-sugar/fat diet (HSF). Male Wistar rats were divided into six groups to receive the control diet (C) or the HSF for 6, 12 or 24 weeks. HSF increased the adiposity index in all HSF groups compared with the C group. HSF was associated with higher plasma TAG, glucose, insulin and leptin levels. Homeostasis model assessment increased in HSF compared with C rats at 24 weeks. Both TNF-α and IL-6 were elevated in the epididymal adipose tissue of HSF rats at 24 weeks compared with HSF at 6 weeks and C at 24 weeks. Only the HSF group at 24 weeks showed increased expression of both Toll-like receptor-4 and NF-κB. More inflammatory cells were found in the HSF group at 24 weeks. We can conclude that the metabolic syndrome occurs independently of the inflammatory response in adipose tissue and that inflammation is associated with hypertrophy of adipocytes, which varies according to duration of exposure to the HSF.
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Affiliation(s)
| | | | - Igor Otávio Minatel
- São Paulo State University, Institute of Bioscience, Botucatu, São Paulo, Brazil
| | - Marcos Correa Dias
- Institute of Health Sciences, Federal University of Mato Grosso (UFMT), Sinop, Mato Grosso, Brazil
| | | | | | - Ana Lúcia A. Ferreira
- São Paulo State University (UNESP), Botucatu Medical School, Botucatu, São Paulo, Brazil
| | - Camila Renata Corrêa
- São Paulo State University (UNESP), Botucatu Medical School, Botucatu, São Paulo, Brazil
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Bostick B, Habibi J, Ma L, Aroor A, Rehmer N, Hayden MR, Sowers JR. Dipeptidyl peptidase inhibition prevents diastolic dysfunction and reduces myocardial fibrosis in a mouse model of Western diet induced obesity. Metabolism 2014; 63:1000-11. [PMID: 24933400 PMCID: PMC4128682 DOI: 10.1016/j.metabol.2014.04.002] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 04/04/2014] [Accepted: 04/04/2014] [Indexed: 12/14/2022]
Abstract
OBJECTIVE Consumption of a high-fat/high-fructose Western diet (WD) is linked to rising obesity and heart disease, particularly diastolic dysfunction which characterizes early obesity/metabolic cardiomyopathy. Mounting evidence supports a role for inflammation, oxidative stress and fibrosis in the pathophysiology of metabolic cardiomyopathy. Dipeptidyl peptidase-4 (DPP-4) is a circulating exopeptidase recently reported to be elevated in the plasma of patients with insulin resistance (IR), obesity and heart failure. We hypothesized that a model of WD induced obesity/metabolic cardiomyopathy would exhibit increased DPP-4 activity and cardiac fibrosis with DPP-4 inhibition preventing cardiac fibrosis and the associated diastolic dysfunction. MATERIALS/METHODS Four-week-old C57BL6/J mice were fed a high-fat/high-fructose WD with the DPP-4 inhibitor MK0626 for 16 weeks. Cardiac function was examined by high-resolution cine-cardiac magnetic resonance imaging (MRI). Phenotypic analysis included measurements of body and heart weight, systemic IR and DPP-4 activity. Immunohistochemistry and transmission electron microscopy (TEM) were utilized to identify underlying pathologic mechanisms. RESULTS We found that chronic WD consumption caused obesity, IR, elevated plasma DPP-4 activity, heart enlargement and diastolic dysfunction. DPP-4 inhibition with MK0626 in WD fed mice resulted in >75% reduction in plasma DPP-4 activity, improved IR and normalized diastolic relaxation. WD consumption induced myocardial oxidant stress and fibrosis with amelioration by MK0626. TEM of hearts from WD fed mice revealed abnormal mitochondrial and perivascular ultrastructure partially corrected by MK0626. CONCLUSIONS This study provides evidence of a role for increased DPP-4 activity in metabolic cardiomyopathy and a potential role for DPP-4 inhibition in prevention and/or correction of oxidant stress/fibrosis and associated diastolic dysfunction.
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Affiliation(s)
- Brian Bostick
- Division of Cardiovascular Medicine, Diabetes Cardiovascular Center, University of Missouri, Columbia, MO, USA; Department of Medicine, University of Missouri, Columbia, MO, USA; Harry S. Truman Memorial Veterans Hospital, Columbia MO, USA
| | - Javad Habibi
- Department of Medicine, University of Missouri, Columbia, MO, USA; Harry S. Truman Memorial Veterans Hospital, Columbia MO, USA; Division of Endocrinology and Metabolism, Diabetes Cardiovascular Center, University of Missouri, Columbia, MO, USA
| | - Lixin Ma
- Harry S. Truman Memorial Veterans Hospital, Columbia MO, USA; Department of Radiology, University of Missouri, Columbia, MO, USA
| | - Annayya Aroor
- Department of Medicine, University of Missouri, Columbia, MO, USA; Harry S. Truman Memorial Veterans Hospital, Columbia MO, USA; Division of Endocrinology and Metabolism, Diabetes Cardiovascular Center, University of Missouri, Columbia, MO, USA
| | - Nathan Rehmer
- Department of Medicine, University of Missouri, Columbia, MO, USA; Harry S. Truman Memorial Veterans Hospital, Columbia MO, USA; Division of Endocrinology and Metabolism, Diabetes Cardiovascular Center, University of Missouri, Columbia, MO, USA
| | - Melvin R Hayden
- Department of Medicine, University of Missouri, Columbia, MO, USA; Harry S. Truman Memorial Veterans Hospital, Columbia MO, USA; Division of Endocrinology and Metabolism, Diabetes Cardiovascular Center, University of Missouri, Columbia, MO, USA
| | - James R Sowers
- Department of Medicine, University of Missouri, Columbia, MO, USA; Harry S. Truman Memorial Veterans Hospital, Columbia MO, USA; Division of Endocrinology and Metabolism, Diabetes Cardiovascular Center, University of Missouri, Columbia, MO, USA; Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, USA.
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Roysommuti S, Wyss JM. Perinatal taurine exposure affects adult arterial pressure control. Amino Acids 2012; 46:57-72. [PMID: 23070226 DOI: 10.1007/s00726-012-1417-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Accepted: 10/04/2012] [Indexed: 12/13/2022]
Abstract
Taurine is an abundant, free amino acid found in mammalian cells that contributes to many physiologic functions from that of a simple cell osmolyte to a programmer of adult health and disease. Taurine's contribution extends from conception throughout life, but its most critical exposure period is during perinatal life. In adults, taurine supplementation prevents or alleviates cardiovascular disease and related complications. In contrast, low taurine consumption coincides with increased risk of cardiovascular disease, obesity and type II diabetes. This review focuses on the effects that altered perinatal taurine exposure has on long-term mechanisms that control adult arterial blood pressure and could thereby contribute to arterial hypertension through its ability to program these cardiovascular regulatory mechanisms very early in life. The modifications of these mechanisms can last a lifetime and transfer to the next generation, suggesting that epigenetic mechanisms underlie the changes. The ability of perinatal taurine exposure to influence arterial pressure control mechanisms and hypertension in adult life appears to involve the regulation of growth and development, the central and autonomic nervous system, the renin-angiotensin system, glucose-insulin interaction and changes to heart, blood vessels and kidney function.
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Affiliation(s)
- Sanya Roysommuti
- Department of Physiology, Faculty of Medicine, Khon Kaen University, Khon Kaen, 40002, Thailand,
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Hayden MR, Joginpally T, Salam M, Sowers JR. Childhood and adolescent obesity in cardiorenal metabolic syndrome and Type 2 diabetes: a clinical vignette and ultrastructure study. ACTA ACUST UNITED AC 2011. [DOI: 10.2217/dmt.11.50] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Hayden MR, Sowers KM, Pulakat L, Joginpally T, Krueger B, Whaley-Connell A, Sowers JR. Possible Mechanisms of Local Tissue Renin-Angiotensin System Activation in the Cardiorenal Metabolic Syndrome and Type 2 Diabetes Mellitus. Cardiorenal Med 2011; 1:193-210. [PMID: 22096455 DOI: 10.1159/000329926] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Accepted: 06/07/2011] [Indexed: 01/08/2023] Open
Abstract
The role of local tissue renin-angiotensin system (tRAS) activation in the cardiorenal metabolic syndrome (CRS) and type 2 diabetes mellitus (T2DM) is not well understood. To this point, we posit that early redox stress-mediated injury to tissues and organs via accumulation of excessive reactive oxygen species (ROS) and associated wound healing responses might serve as a paradigm to better understand how tRAS is involved. There are at least five common categories responsible for generating ROS that may result in a positive feedback ROS-tRAS axis. These mechanisms include metabolic substrate excess, hormonal excess, hypoxia-ischemia/reperfusion, trauma, and inflammation. Because ROS are toxic to proteins, lipids, and nucleic acids they may be the primary instigator, serving as the injury nidus to initiate the wound healing process. Insulin resistance is central to the development of the CRS and T2DM, and there are now thought to be four major organ systems important in their development. In states of overnutrition and tRAS activation, adipose tissue, skeletal muscle (SkM), islet tissues, and liver (the quadrumvirate) are individually and synergistically related to the development of insulin resistance, CRS, and T2DM. The obesity epidemic is thought to be the driving force behind the CRS and T2DM, which results in the impairment of multiple end-organs, including the cardiovascular system, pancreas, kidney, retina, liver, adipose tissue, SkM, and nervous system. A better understanding of the complex mechanisms leading to local tRAS activation and increases in tissue ROS may lead to new therapies emphasizing global risk reduction of ROS resulting in decreased morbidity and mortality.
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Affiliation(s)
- Melvin R Hayden
- Department of Internal Medicine, University of Missouri-Columbia School of Medicine, Columbia, Mo., USA
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Pulakat L, DeMarco VG, Whaley-Connell A, Sowers JR. The Impact of Overnutrition on Insulin Metabolic Signaling in the Heart and the Kidney. Cardiorenal Med 2011; 1:102-112. [PMID: 22258397 DOI: 10.1159/000327140] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Overnutrition characterized by overconsumption of food rich in fat and carbohydrates is a significant contributor to hypertension, type 2 diabetes, and the cardiorenal syndrome. Overnutrition activates the renin-angiotensin-aldosterone system (RAAS) and causes chronic exposure of cardiovascular and renal tissue to increased circulating nutrients, insulin (INS), and angiotensin II (ANG II). Emerging evidence suggests that overnutrition, aldosterone, and ANG II promote INS resistance, a chronic condition that underlies these co-morbidities, through activation of the mammalian target of the rapamycin (mTOR)/S6 kinase 1 (S6K1) signaling pathway in cardiovascular tissue and the kidney. However, a novel ANG II type 2 receptor (AT2R)-mediated cross talk between the RAAS and mTOR pathways ameliorates overnutrition-induced activation of mTOR/S6K1 signaling in cardiovascular tissue of rats, mice, and humans and confers cardioprotection.
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Klachko D, Whaley-Connell A. Use of Metformin in Patients with Kidney and Cardiovascular Diseases. Cardiorenal Med 2011; 1:87-95. [PMID: 22294985 PMCID: PMC3263972 DOI: 10.1159/000327151] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Metformin is an insulin-sensitizing agent with anti-hyperglycemic properties that is widely used for the treatment of type-2 diabetes. The efficacy of metformin in reducing hyperglycemia is well established, and there is emerging evidence that its chronic use is associated with cancer and cardiovascular disease (CVD) risk reduction. While the hypoglycemic properties of metformin are largely attributed to suppression of hepatic glucose production and increases in peripheral tissue insulin sensitivity, the precise mechanism of the hypoglycemic action of metformin remains unclear. There is evidence that metformin use interrupts mitochondrial oxidative stress in the liver and corrects abnormalities of intracellular calcium metabolism in insulin-sensitive tissues (liver, skeletal muscle, and adipocytes) and cardiovascular tissue. However, the use of metformin in patients with kidney disease, a high-risk CVD state, is confounded by confusion regarding appropriate concerns about the development of lactic acidosis in this population. Thus, we will review current evidence on metformin use for improving CVD outcomes and its therapeutic use in kidney disease.
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Affiliation(s)
- David Klachko
- Division of Endocrinology, University of Missouri-Columbia School of Medicine, Columbia, Mo., USA
| | - Adam Whaley-Connell
- Division of Nephrology, Department of Internal Medicine, University of Missouri-Columbia School of Medicine, Columbia, Mo., USA
- Division of Harry S. Truman VA Medical Center, Columbia, Mo., USA
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Hayden MR, Sowers JR. Childhood-Adolescent Obesity in the Cardiorenal Syndrome: Lessons from Animal Models. Cardiorenal Med 2011; 1:75-86. [PMID: 22294984 DOI: 10.1159/000327022] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2011] [Accepted: 03/02/2011] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS Childhood-adolescent overweight and obesity have grown to pandemic proportions during the past decade. The onset of obesity in younger adults will likely be manifested as earlier onset of myocardial and renal end-organ disease in younger adults. For the first time, it is estimated that the current generation may not live to be as old as their parents. Thus, it is important to develop animal models of childhood obesity to understand fundamental pathological organ changes. METHODS In this regard, we utilize transmission electron microscopy evaluation to evaluate early remodeling changes of two adolescent rodent obesity models: the Zucker obese (fa/fa) rat and the db/db mouse models of obesity. We have concentrated on the initial ultrastructural remodeling (obese adipose tissue, skeletal muscle, and islet remodeling) and the associated changes in target end organs (including the myocardium and kidney) in young rodent models of obesity and insulin resistance, collectively manifesting as the cardiorenal metabolic syndrome (CRS). RESULTS Briefly, tissues revealed the following ultrastructural remodeling abnormalities: inflammation, hypertrophy, and early fibrosis in adipose tissue; loss of mitochondria in skeletal muscles, hyperplasia, fibrosis, and depletion of insulin-secretory granules in pancreatic islets; increased intramyocardial lipid accumulation, fibrosis, and mitochondrial deposition in the myocardium, and obesity-related glomerulopathy and tubulopathy in the kidney. CONCLUSION Based on the current knowledge and ultrastructural observations of organ pathology, we propose mechanisms whereby obesity appears to be the driving force behind the development of the CRS.
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