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Abstract
Perivascular adipose tissue (PVAT) refers to the local aggregate of adipose tissue surrounding the vascular tree, exhibiting phenotypes from white to brown and beige adipocytes. Although PVAT has long been regarded as simply a structural unit providing mechanical support to vasculature, it is now gaining reputation as an integral endocrine/paracrine component, in addition to the well-established modulator endothelium, in regulating vascular tone. Since the discovery of anti-contractile effect of PVAT in 1991, the use of multiple rodent models of reduced amounts of PVAT has revealed its regulatory role in vascular remodeling and cardiovascular implications, including atherosclerosis. PVAT does not only release PVAT-derived relaxing factors (PVRFs) to activate multiple subsets of endothelial and vascular smooth muscle potassium channels and anti-inflammatory signals in the vasculature, but it does also provide an interface for neuron-adipocyte interactions in the vascular wall to regulate arterial vascular tone. In this review, we outline our current understanding towards PVAT and attempt to provide hints about future studies that can sharpen the therapeutic potential of PVAT against cardiovascular diseases and their complications.
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Affiliation(s)
- Chak Kwong Cheng
- School of Biomedical Sciences, Chinese University of Hong Kong, Hong Kong, SAR, China
- Institute of Vascular Medicine, Shenzhen Research Institute and Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, Hong Kong, SAR, China
| | - Hamidah Abu Bakar
- Health Sciences Department, Universiti Selangor, 40000, Shah Alam, Selangor, Malaysia
| | - Maik Gollasch
- Experimental and Clinical Research Center (ECRC)-a joint cooperation between the Charité-University Medicine Berlin and the Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 13125, Berlin, Germany.
- Medical Clinic for Nephrology and Internal Intensive Care, Charité Campus Virchow Klinikum, Augustenburger Platz 1, 13353, Berlin, Germany.
| | - Yu Huang
- School of Biomedical Sciences, Chinese University of Hong Kong, Hong Kong, SAR, China.
- Institute of Vascular Medicine, Shenzhen Research Institute and Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, Hong Kong, SAR, China.
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Ravichandran G, Lakshmanan DK, Raju K, Elangovan A, Nambirajan G, Devanesan AA, Thilagar S. Food advanced glycation end products as potential endocrine disruptors: An emerging threat to contemporary and future generation. ENVIRONMENT INTERNATIONAL 2019; 123:486-500. [PMID: 30622074 DOI: 10.1016/j.envint.2018.12.032] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 12/14/2018] [Accepted: 12/15/2018] [Indexed: 06/09/2023]
Abstract
Mankind exposure to chemicals in the past century has increased dramatically throughout environment. There is no question that chemicals interfere with the physiology of biological system. Abundance of chemicals is documented to be detrimental to human and wildlife. The mammalian endocrine system is comprised of many interacting tissues mediate themselves through hormones that are essential for metabolism, growth and development. Humans secrete over fifty different hormones to orchestrate major physiological functions however; these vital functions can be intervened by huge number of internal and external chemical stressors that are identified as endocrine disruptors. Advanced glycation end products (AGEs), familiarly known as Maillard products, formed through non-enzymatic glycation whose production is augmented on aging as well as environmental stressors. Processed foods have become very popular today due to their taste, convenience, and inexpensiveness. Manufacture of these day-to-day foods involves extreme temperatures on processing results in the formation of AGEs could independently promote oxidative stress, aging, diabetes, cancer, degenerative diseases, more fascinatingly hormonal disruption is the subject of interest of this review. Based on some substantial observations documented till time, we discuss the emergence of dietary AGEs as potential endocrine disruptors by emphasizing their occurrence, mechanisms and participation in endocrine interruption. Both economically and in terms of human life, AGEs may represent an enormous cost for the future society. Therefore, by explicating their novel role in endocrine diseases, the review strives to make an impact on AGEs and their exposure among public as well as scientific communities.
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Affiliation(s)
- Guna Ravichandran
- Department of Environmental Biotechnology, School of Environmental Sciences, Bharathidasan University, Tiruchirappalli, Tamilnadu, India
| | - Dinesh Kumar Lakshmanan
- Department of Environmental Biotechnology, School of Environmental Sciences, Bharathidasan University, Tiruchirappalli, Tamilnadu, India
| | - Karthik Raju
- Department of Environmental Biotechnology, School of Environmental Sciences, Bharathidasan University, Tiruchirappalli, Tamilnadu, India
| | - Abbirami Elangovan
- Department of Environmental Biotechnology, School of Environmental Sciences, Bharathidasan University, Tiruchirappalli, Tamilnadu, India
| | - Gayathri Nambirajan
- Department of Environmental Biotechnology, School of Environmental Sciences, Bharathidasan University, Tiruchirappalli, Tamilnadu, India
| | - Arul Ananth Devanesan
- Department of Food Quality and Safety, Gilat Research Center, Agricultural Research Organization, M.P. Negev 85280, Israel
| | - Sivasudha Thilagar
- Department of Environmental Biotechnology, School of Environmental Sciences, Bharathidasan University, Tiruchirappalli, Tamilnadu, India.
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NAKAO K. Translational science: Newly emerging science in biology and medicine - Lessons from translational research on the natriuretic peptide family and leptin. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2019; 95:538-567. [PMID: 31708497 PMCID: PMC6856003 DOI: 10.2183/pjab.95.037] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 08/30/2019] [Indexed: 06/10/2023]
Abstract
Translation is the process of turning observations in the laboratory, clinic, and community into interventions that improve the health of individuals and the public, ranging from diagnostics and therapeutics to medical procedures and behavioral changes. Translational research is defined as the effort to traverse a particular step of the translation process for a particular target or disease. Translational science is a newly emerging science, distinct from basic and clinical sciences in biology and medicine, and is a field of investigation focused on understanding the scientific and operational principles underlying each step of the translational process. Advances in translational science will increase the efficacy and safety of translational research in all diagnostic and therapeutic areas. This report examines translational research on novel hormones, the natriuretic peptide family and leptin, which have achieved clinical applications or for which studies are still ongoing, and also emphasizes the lessons that translational science has learned from more than 30 years' experience in translational research.
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Affiliation(s)
- Kazuwa NAKAO
- Medical Innovation Center, Kyoto University Graduate School of Medicine, Kyoto, Japan
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Nishitani S, Fukuhara A, Shin J, Okuno Y, Otsuki M, Shimomura I. Metabolomic and microarray analyses of adipose tissue of dapagliflozin-treated mice, and effects of 3-hydroxybutyrate on induction of adiponectin in adipocytes. Sci Rep 2018; 8:8805. [PMID: 29891844 PMCID: PMC5995811 DOI: 10.1038/s41598-018-27181-y] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 05/30/2018] [Indexed: 12/11/2022] Open
Abstract
Sodium/glucose cotransporter 2 (SGLT2) inhibitor improves systemic glucose metabolism. To clarify the effect of dapagliflozin, we performed gene expression microarray and metabolomic analyses of murine adipose tissue. Three groups of mice were used; non-diabetic control KK mice (KK), diabetic KKAy mice (KKAy), and KKAy mice treated with dapagliflozin (KKAy + Dapa). Plasma glucose levels were significantly reduced in KKAy + Dapa compared with KKAy. Food consumption was larger in KKAy + Dapa than KKAy, and there were no significant differences in body and adipose tissue weight among the groups. Metabolomic analysis showed higher levels of many intermediate metabolites of the glycolytic pathway and TCA cycle in KKAy than KK, albeit insignificantly. Dapagliflozin partially improved accumulation of glycolytic intermediate metabolites, but not intermediate metabolites of the TCA cycle, compared with KKAy. Interestingly, dapagliflozin increased plasma and adipose 3-hydroxybutyric acid (3-HBA) levels. Microarray analysis showed that adipocytokines were downregulated in KKAy compared with KK mice, and upregulated by dapagliflozin. In vitro, 3-HBA induced β-hydroxybutyrylation of histone H3 at lysine 9 and upregulation of adiponectin in 3T3-L1 adipocytes independent of their acetylation or methylation. Our results suggest that 3-HBA seems to provide protection through epigenetic modifications of adiponectin gene in adipocytes.
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Affiliation(s)
- Shigeki Nishitani
- Departments of Metabolic Medicine, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Atsunori Fukuhara
- Departments of Metabolic Medicine, Osaka University Graduate School of Medicine, Suita, Osaka, Japan. .,Departments of Adipose Management, Osaka University Graduate School of Medicine, Suita, Osaka, Japan.
| | - Jihoon Shin
- Departments of Metabolic Medicine, Osaka University Graduate School of Medicine, Suita, Osaka, Japan.,Departments of Diabetes Care Medicine, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Yosuke Okuno
- Departments of Metabolic Medicine, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Michio Otsuki
- Departments of Metabolic Medicine, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Iichiro Shimomura
- Departments of Metabolic Medicine, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
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Inamori KI, Ito H, Tamura Y, Nitta T, Yang X, Nihei W, Shishido F, Imazu S, Tsukita S, Yamada T, Katagiri H, Inokuchi JI. Deficient ganglioside synthesis restores responsiveness to leptin and melanocortin signaling in obese KKAy mice. J Lipid Res 2018; 59:1472-1481. [PMID: 29880531 DOI: 10.1194/jlr.m085753] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 05/22/2018] [Indexed: 11/20/2022] Open
Abstract
GM3, a precursor for synthesis of a- and b-series gangliosides, is elevated in adipocytes of obese model animals and in sera of obese human patients with type 2 diabetes and/or dyslipidemia. GM3 synthase (GM3S)-KO C57BL/6 mice display enhanced insulin sensitivity and reduced development of high-fat diet-induced insulin resistance. However, the pathophysiological roles of GM3 and related gangliosides in the central control of feeding and metabolism remain unclear. We found that a mouse model (KKAy GM3S KO) generated by KO of the GM3S gene in the yellow obese strain, KKAy, displayed significant amelioration of obese phenotype. Whereas KKAy mice were hyperphagic and developed severe obesity, KKAy GM3S KO mice had significantly lower body weight and food intake, and greater glucose and insulin tolerance. The hypothalamic response to intraperitoneal administration of leptin was greatly reduced in KKAy mice, but was retained in KKAy GM3S KO mice. In studies of a cultured mouse hypothalamic neuronal cell line, enhanced leptin-dependent phosphorylation of ERK was observed in GM3S-deficient cells. Furthermore, KKAy GM3S KO mice did show altered coat color, suggesting that GM3S is also involved in melanocortin signaling. Our findings, taken together, indicate that GM3-related gangliosides play key roles in leptin and melanocortin signaling.
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Affiliation(s)
- Kei-Ichiro Inamori
- Division of Glycopathology, Institute of Molecular Biomembrane and Glycobiology, Tohoku Medical and Pharmaceutical University, Sendai, Miyagi 981-8558, Japan
| | - Hideki Ito
- Division of Glycopathology, Institute of Molecular Biomembrane and Glycobiology, Tohoku Medical and Pharmaceutical University, Sendai, Miyagi 981-8558, Japan
| | - Yumi Tamura
- Division of Glycopathology, Institute of Molecular Biomembrane and Glycobiology, Tohoku Medical and Pharmaceutical University, Sendai, Miyagi 981-8558, Japan
| | - Takahiro Nitta
- Division of Glycopathology, Institute of Molecular Biomembrane and Glycobiology, Tohoku Medical and Pharmaceutical University, Sendai, Miyagi 981-8558, Japan
| | - Xiaohua Yang
- Division of Glycopathology, Institute of Molecular Biomembrane and Glycobiology, Tohoku Medical and Pharmaceutical University, Sendai, Miyagi 981-8558, Japan
| | - Wataru Nihei
- Division of Glycopathology, Institute of Molecular Biomembrane and Glycobiology, Tohoku Medical and Pharmaceutical University, Sendai, Miyagi 981-8558, Japan
| | - Fumi Shishido
- Division of Glycopathology, Institute of Molecular Biomembrane and Glycobiology, Tohoku Medical and Pharmaceutical University, Sendai, Miyagi 981-8558, Japan
| | - Susumu Imazu
- Nippon Boehringer Ingelheim Company, Ltd., Shinagawa-Ku, Tokyo 141-6017, Japan
| | - Sohei Tsukita
- Department of Metabolism and Diabetes, Tohoku University Graduate School of Medicine, Sendai, Miyagi 980-8575, Japan
| | - Tetsuya Yamada
- Department of Metabolism and Diabetes, Tohoku University Graduate School of Medicine, Sendai, Miyagi 980-8575, Japan
| | - Hideki Katagiri
- Department of Metabolism and Diabetes, Tohoku University Graduate School of Medicine, Sendai, Miyagi 980-8575, Japan
| | - Jin-Ichi Inokuchi
- Division of Glycopathology, Institute of Molecular Biomembrane and Glycobiology, Tohoku Medical and Pharmaceutical University, Sendai, Miyagi 981-8558, Japan
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Nepali S, Cha JY, Ki HH, Lee HY, Kim YH, Kim DK, Song BJ, Lee YM. Chrysanthemum indicum Inhibits Adipogenesis and Activates the AMPK Pathway in High-Fat-Diet-Induced Obese Mice. THE AMERICAN JOURNAL OF CHINESE MEDICINE 2018; 46:119-136. [DOI: 10.1142/s0192415x18500076] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Chrysanthemum indicum (CI) is widely distributed in China and many parts of the tropical world, and has been reported to have antibacterial, antiviral, anti-oxidant and immunomodulatory effects, but no information is available on its effects on high fat diet (HFD)-induced obesity. This was undertaken to investigate the mechanism responsible for the effect of ethyl acetate fraction of CI (CIEA) on adipogenesis, in vitro and in vivo models of obesity. In the in vitro study, differentiating 3T3-L1 cells were treated with media to initiate differentiation (MDI) in the presence or absence of CIEA with different concentrations, and in the in vivo study, C57BL/6 mice were fed with HFD and administered CIEA daily for six weeks. Garcinia cambogia (GC) was used as the positive control, and was administered in the same manner as CIEA. Results showed CIEA reduced HFD-induced body weight gain, epididymal white adipose tissue (eWAT), and liver weight. In addition, CIEA significantly decreased serum lipid profiles, including total cholesterol (TC), triglyceride (TG) and low density lipoprotein cholesterol (LDLc) and increased high density lipoprotein cholesterol (HDLc) levels. Furthermore, CIEA also reduced leptin levels and increased adiponectin levels in serum, and significantly decreased peroxisome proliferator-activated receptor [Formula: see text] (PPAR[Formula: see text]) and CCAAT/enhancer-binding protein (C/EPBs) levels, but increased PPAR[Formula: see text] level and the phosphorylation of AMP-activated protein kinase (AMPK) in eWATs and in the liver tissues of HFD fed obese mice. Taken together, these results indicate CIEA might be beneficial for preventing obesity.
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Affiliation(s)
- Sarmila Nepali
- Department of Immunology and Institute of Medical Sciences, Medical School, Chonbuk National University, Jeonju, Jeonbuk 54907, Korea
| | - Ji-Yun Cha
- Department of Oriental Pharmacy, College of Pharmacy and Wonkwang-Oriental Medicines Research Institute, Korea
| | - Hyeon-Hui Ki
- Department of Immunology and Institute of Medical Sciences, Medical School, Chonbuk National University, Jeonju, Jeonbuk 54907, Korea
- Department of Oriental Pharmacy, College of Pharmacy and Wonkwang-Oriental Medicines Research Institute, Korea
| | - Hoon-Yeon Lee
- Department of Oriental Pharmacy, College of Pharmacy and Wonkwang-Oriental Medicines Research Institute, Korea
| | - Young-Ho Kim
- College of Pharmacy, Chungnam National University, Daejeon 305-764, Korea
| | - Dae-Ki Kim
- Department of Immunology and Institute of Medical Sciences, Medical School, Chonbuk National University, Jeonju, Jeonbuk 54907, Korea
| | - Bong-Joon Song
- Department of Food Science and Biotechnology, Wonkwang University, Iksan, Jeonbuk 54538, Korea
| | - Young-Mi Lee
- Department of Oriental Pharmacy, College of Pharmacy and Wonkwang-Oriental Medicines Research Institute, Korea
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Kadowaki T, Hara K, Yamauchi T, Terauchi Y, Tobe K, Nagai R. Molecular Mechanism of Insulin Resistance and Obesity. Exp Biol Med (Maywood) 2016; 228:1111-7. [PMID: 14610248 DOI: 10.1177/153537020322801003] [Citation(s) in RCA: 139] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Obesity and insulin resistance have been recognized as leading causes of major health issues. We have endeavored to depict the molecular mechanism of insulin resistance, focusing on the function of adipocyte. We have investigated a role of PPARgamma on the pathogenesis of Type II diabetes. Heterozygous PPARgamma-deficient mice were protected from the development of insulin resistance due to adipocyte hypertrophy under a high-fat diet. Moreover, a Pro12Ala polymorphism in the human PPARgamma2 gene was associated with decreased risk of Type II diabetes in Japanese. Taken together with these results, PPARgamma is proved to be a thrifty gene mediating Type II diabetes. Pharmacological inhibitors of PPARgamma/RXR ameliorate high-fat diet-induced insulin resistance in animal models of Type II diabetes. We have performed a genome-wide scan of Japanese Type 2 diabetic families using affected sib pair analysis. Our genome scan reveals at least 9 chromosomal regions potentially harbor susceptibility genes of Type II diabetes in Japanese. Among these regions, 3q26-q28 appeared to be very attractive one, because of the gene encoding adiponectin, the expression of which we had found enhanced in insulin-sensitive PPARgamma-deficient mice. Indeed, the subjects with the G/G genotype of SNP276 in the adiponectin gene were at increased risk for Type II diabetes compared with those having the T/T genotype. The plasma adiponectin levels were lower in the subjects with the G allele, suggesting that genetically inherited decrease in adiponectin levels predispose subjects to insulin resistance and Type II diabetes. Our work also confirmed that replenishment of adiponectin represents a novel treatment strategy for insulin resistance and Type II diabetes using animal models. Further investigation will be needed to clarify how adiponectin exerts its effect and to discover the molecular target of therapies.
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Affiliation(s)
- Takashi Kadowaki
- Department of Metabolic Diseases, Graduate School of Medicine, University of Tokyo, Tokyo 113-8655, Japan.
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Tsubai T, Noda Y, Ito K, Nakao M, Seino Y, Oiso Y, Hamada Y. Insulin elevates leptin secretion and mRNA levels via cyclic AMP in 3T3-L1 adipocytes deprived of glucose. Heliyon 2016; 2:e00194. [PMID: 27896318 PMCID: PMC5121139 DOI: 10.1016/j.heliyon.2016.e00194] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2016] [Revised: 10/17/2016] [Accepted: 11/08/2016] [Indexed: 02/04/2023] Open
Abstract
Aims Leptin plays an important role in the pathogenesis of obesity and diabetes, yet the regulatory mechanisms of this hormone have not been fully elucidated. In this study, we aimed to clarify the roles of insulin and glucose in leptin secretion and mRNA production using inhibitors of insulin signal transduction in adipocytes cultured under glucose-free or normal conditions. Methods Differentiated 3T3-L1 adipocytes were stimulated with insulin in combination with inhibitors for phosphoinositide 3-kinase (PI3K), Akt, and phosphodiesterase 3B (PDE3B), as well as epinephrine and a cyclic AMP (cAMP) analog under glucose-free or normal conditions. After 8 h of stimulation, leptin protein levels in the media and leptin mRNA expression levels in the adipocytes were measured. Results Insulin significantly increased the secretion and mRNA levels of leptin under the depletion of glucose. Glucose augmented basal leptin secretion without insulin, while glucose nullified insulin-induced leptin mRNA upregulation. The PI3K inhibitor BEZ-235, the Akt inhibitor MK-2206, and the PDE3B inhibitor cilostazol attenuated the insulin stimulation of leptin secretion, but did not suppress the insulin-induced leptin mRNA upregulation with glucose depletion. In contrast to the glucose-free condition, insulin failed to upregulate leptin mRNA in the presence of glucose. The cAMP analog dibutyryl cAMP and epinephrine decreased both leptin secretion and mRNA regardless of glucose supplementation. Conclusion Insulin alone stimulates leptin secretion and elevates leptin mRNA levels via cAMP under the lack of glucose metabolism, while glucose is a significant and ambivalent effector on the insulin effects of leptin.
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Affiliation(s)
- Tomomi Tsubai
- College of Pharmacy, Kinjo Gakuin University; Omori 2-1723, Moriyama-ku, Nagoya 463-8521, Japan
- Division of Clinical Science and Neuropsychopharmacology, Graduate School and Faculty of Pharmacy, Meijo University; 150, Yagotoyama, Tempaku-ku, Nagoya 468-8503, Japan
| | - Yukihiro Noda
- Division of Clinical Science and Neuropsychopharmacology, Graduate School and Faculty of Pharmacy, Meijo University; 150, Yagotoyama, Tempaku-ku, Nagoya 468-8503, Japan
| | - Kazuma Ito
- Division of Clinical Science and Neuropsychopharmacology, Graduate School and Faculty of Pharmacy, Meijo University; 150, Yagotoyama, Tempaku-ku, Nagoya 468-8503, Japan
| | - Makoto Nakao
- College of Pharmacy, Kinjo Gakuin University; Omori 2-1723, Moriyama-ku, Nagoya 463-8521, Japan
| | - Yusuke Seino
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine; 65, Tsuruma-cho, Showa-ku, Nagoya 466-8560, Japan
| | - Yutaka Oiso
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine; 65, Tsuruma-cho, Showa-ku, Nagoya 466-8560, Japan
| | - Yoji Hamada
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine; 65, Tsuruma-cho, Showa-ku, Nagoya 466-8560, Japan
- Corresponding author at: Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsuruma-cho, Showa-ku, Nagoya 466–8550, Japan.
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Anti-Obesity and Hypoglycemic Effects of Poncirus trifoliata L. Extracts in High-Fat Diet C57BL/6 Mice. Molecules 2016; 21:453. [PMID: 27058520 PMCID: PMC6273343 DOI: 10.3390/molecules21040453] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 03/23/2016] [Accepted: 03/30/2016] [Indexed: 01/04/2023] Open
Abstract
The present study investigated the possible anti-obesity and hypoglycemic effects of Poncirus trifoliata L. extracts. Mature fruit were divided into flavedo (PF) and juice sacs (PJ), and extracts from them were tested on C57BL/6 mice fed a high-fat diet (HFD) for thirteen weeks. Both fruit extracts (40 mg/kg body weight, respectively) showed anti-obesity and hypoglycemic effects. Consumption of PF and PJ extracts reduced body weight by 9.21% and 20.27%, respectively. Liver and adipose weights, fasting glucose, serum triglyceride (TG), and low density lipoprotein cholesterol (LDL-c) levels decreased significantly, while serum high density lipoprotein cholesterol (HDL-c) and oral glucose tolerance levels increased significantly in response to two fruit extracts. These effects were due in part to the modulation of serum insulin, leptin, and adiponectin. Furthermore, transcript levels of fatty acid synthase (FAS) and stearoyl-CoA desaturase 1 (SCD1) were reduced while those of carnitine palmitoyltransferase 1α (CPT1α) and insulin receptor substrate 2 (IRS2) were increased in the liver of C57BL/6 mice, which might be an important mechanism affecting lipid and glucose metabolism. Taken together, P. trifoliata fruit can be potentially used to prevent or treat obesity and associated metabolic disorders.
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Jia S, Hu Y, Zhang W, Zhao X, Chen Y, Sun C, Li X, Chen K. Hypoglycemic and hypolipidemic effects of neohesperidin derived from Citrus aurantium L. in diabetic KK-Aymice. Food Funct 2015; 6:878-86. [DOI: 10.1039/c4fo00993b] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The present study is to investigate the possible hypoglycemic and hypolipidemic effects of neohesperidin (NHP) derived fromCitrus aurantiumL.in vivo.
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Affiliation(s)
- Sheng Jia
- Laboratory of Fruit Quality Biology
- Zhejiang University
- Hangzhou
- China
| | - Ying Hu
- Department of Ultrasonography
- The First Affiliated Hospital
- College of Medicine
- Zhejiang University
- Hangzhou
| | - Wenna Zhang
- Laboratory of Fruit Quality Biology
- Zhejiang University
- Hangzhou
- China
| | - Xiaoyong Zhao
- Laboratory of Fruit Quality Biology
- Zhejiang University
- Hangzhou
- China
| | - Yanhong Chen
- Laboratory Animal Centre of Zhejiang University
- Hangzhou
- China
| | - Chongde Sun
- Laboratory of Fruit Quality Biology
- Zhejiang University
- Hangzhou
- China
- Agricultural Products Processing Technology Key Laboratory of Zhejiang Province
| | - Xian Li
- Laboratory of Fruit Quality Biology
- Zhejiang University
- Hangzhou
- China
- Agricultural Products Processing Technology Key Laboratory of Zhejiang Province
| | - Kunsong Chen
- Laboratory of Fruit Quality Biology
- Zhejiang University
- Hangzhou
- China
- Agricultural Products Processing Technology Key Laboratory of Zhejiang Province
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Sakai T, Kusakabe T, Ebihara K, Aotani D, Yamamoto-Kataoka S, Zhao M, Gumbilai VMJ, Ebihara C, Aizawa-Abe M, Yamamoto Y, Noguchi M, Fujikura J, Hosoda K, Inagaki N, Nakao K. Leptin restores the insulinotropic effect of exenatide in a mouse model of type 2 diabetes with increased adiposity induced by streptozotocin and high-fat diet. Am J Physiol Endocrinol Metab 2014; 307:E712-9. [PMID: 25159327 DOI: 10.1152/ajpendo.00272.2014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Leptin may reduce pancreatic lipid deposition, which increases with progression of obesity and can impair β-cell function. The insulinotropic effect of glucagon-like peptide-1 (GLP-1) and the efficacy of GLP-1 receptor agonist are reduced associated with impaired β-cell function. In this study, we examined whether leptin could restore the efficacy of exenatide, a GLP-1 receptor agonist, in type 2 diabetes with increased adiposity. We chronically administered leptin (500 μg·kg⁻¹·day⁻¹) and/or exenatide (20 μg·kg⁻¹·day⁻¹) for 2 wk in a mouse model of type 2 diabetes with increased adiposity induced by streptozotocin and high-fat diet (STZ/HFD mice). The STZ/HFD mice exhibited hyperglycemia, overweight, increased pancreatic triglyceride level, and reduced glucose-stimulated insulin secretion (GSIS); moreover, the insulinotropic effect of exenatide was reduced. However, leptin significantly reduced pancreatic triglyceride level, and adding leptin to exenatide (LEP/EX) remarkably enhanced GSIS. These results suggested that the leptin treatment restored the insulinotropic effect of exenatide in the mice. In addition, LEP/EX reduced food intake, body weight, and triglyceride levels in the skeletal muscle and liver, and corrected hyperglycemia to a greater extent than either monotherapy. The pair-feeding experiment indicated that the marked reduction of pancreatic triglyceride level and enhancement of GSIS by LEP/EX occurred via mechanisms other than calorie restriction. These results suggest that leptin treatment may restore the insulinotropic effect of exenatide associated with the reduction of pancreatic lipid deposition in type 2 diabetes with increased adiposity. Combination therapy with leptin and exenatide could be an effective treatment for patients with type 2 diabetes with increased adiposity.
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Affiliation(s)
- Takeru Sakai
- Department of Diabetes, Endocrinology, and Nutrition, Kyoto University Graduate School of Medicine, Kyoto, Japan; Medical Innovation Center, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Toru Kusakabe
- Medical Innovation Center, Kyoto University Graduate School of Medicine, Kyoto, Japan;
| | - Ken Ebihara
- Institute for Advancement of Clinical and Translational Science, Kyoto University Hospital, Kyoto, Japan; and
| | - Daisuke Aotani
- Medical Innovation Center, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Sachiko Yamamoto-Kataoka
- Department of Diabetes, Endocrinology, and Nutrition, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Mingming Zhao
- Department of Diabetes, Endocrinology, and Nutrition, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | | | - Chihiro Ebihara
- Department of Diabetes, Endocrinology, and Nutrition, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Megumi Aizawa-Abe
- Institute for Advancement of Clinical and Translational Science, Kyoto University Hospital, Kyoto, Japan; and
| | - Yuji Yamamoto
- Department of Diabetes, Endocrinology, and Nutrition, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Michio Noguchi
- Medical Innovation Center, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Junji Fujikura
- Department of Diabetes, Endocrinology, and Nutrition, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Kiminori Hosoda
- Medical Innovation Center, Kyoto University Graduate School of Medicine, Kyoto, Japan; Department of Human Health Science, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Nobuya Inagaki
- Department of Diabetes, Endocrinology, and Nutrition, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Kazuwa Nakao
- Medical Innovation Center, Kyoto University Graduate School of Medicine, Kyoto, Japan
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12
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Masuzaki H. Factors involved in the development of the metabolic syndrome. We are what we eat and what we are eating. INTERNATIONAL JOURNAL OF PEDIATRIC ENDOCRINOLOGY 2013. [PMCID: PMC3849948 DOI: 10.1186/1687-9856-2013-s1-o3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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13
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Beppu F, Hosokawa M, Yim MJ, Shinoda T, Miyashita K. Down-Regulation of Hepatic Stearoyl-CoA Desaturase-1 Expression by Fucoxanthin via Leptin Signaling in Diabetic/Obese KK-A y Mice. Lipids 2013; 48:449-55. [DOI: 10.1007/s11745-013-3784-4] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Accepted: 01/14/2013] [Indexed: 11/28/2022]
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14
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Carvas JM, Vukolic A, Yepuri G, Xiong Y, Popp K, Schmutz I, Chappuis S, Albrecht U, Ming XF, Montani JP, Yang Z. Period2 gene mutant mice show compromised insulin-mediated endothelial nitric oxide release and altered glucose homeostasis. Front Physiol 2012; 3:337. [PMID: 22934083 PMCID: PMC3429102 DOI: 10.3389/fphys.2012.00337] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Accepted: 08/01/2012] [Indexed: 01/18/2023] Open
Abstract
Period2 (Per2) is an important component of the circadian clock. Mutation of this gene is associated with vascular endothelial dysfunction and altered glucose metabolism. The aim of this study is to further characterize whole body glucose homeostasis and endothelial nitric oxide (NO) production in response to insulin in the mPer2Brdm1 mice. We show that mPer2Brdm1 mice exhibit compromised insulin receptor activation and Akt signaling in various tissues including liver, fat, heart, and aortas with a tissue-specific heterogeneous diurnal pattern, and decreased insulin-stimulated NO release in the aortas in both active and inactive phases of the animals. As compared to wild type (WT) mice, the mPer2Brdm1 mice reveal hyperinsulinemia, hypoglycemia with lower fasting hepatic glycogen content and glycogen synthase level, no difference in glucose tolerance and insulin tolerance. The mPer2Brdm1 mice do not show increased predisposition to obesity either on normal chow or high fat diet compared to WT controls. Thus, mice with Per2 gene mutation show altered glucose homeostasis and compromised insulin-stimulated NO release, independently of obesity.
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Affiliation(s)
- João M Carvas
- Faculty of Science, Division of Physiology, Department of Medicine, University of Fribourg Fribourg, Switzerland
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15
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Combination of fucoxanthin and conjugated linoleic acid attenuates body weight gain and improves lipid metabolism in high-fat diet-induced obese rats. Arch Biochem Biophys 2012; 519:59-65. [DOI: 10.1016/j.abb.2012.01.011] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2011] [Revised: 12/28/2011] [Accepted: 01/14/2012] [Indexed: 12/22/2022]
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16
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Aprahamian TR, Sam F. Adiponectin in cardiovascular inflammation and obesity. Int J Inflam 2011; 2011:376909. [PMID: 21941676 PMCID: PMC3175407 DOI: 10.4061/2011/376909] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Revised: 06/08/2011] [Accepted: 06/10/2011] [Indexed: 01/08/2023] Open
Abstract
Inflammation is
widely known to play a key role in the
development and progression of cardiovascular
diseases. It is becoming increasingly evident
that obesity is linked to many proinflammatory
and obesity-associated cardiovascular conditions
(e.g., metabolic syndrome, acute coronary
syndrome, and congestive heart failure). It has
been observed that adipokines play an
increasingly large role in systemic and local
inflammation. Therefore, adipose tissue may have
a more important role than previously thought in
the pathogenesis of several disease types. This
review explores the recently described role of
adiponectin as an immunomodulatory factor and
how it intersects with the inflammation
associated with both cardiovascular and
autoimmune pathologies.
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Affiliation(s)
- Tamar R Aprahamian
- Renal Section, Evans Department of Medicine, Boston University School of Medicine, Boston, MA 02118, USA
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17
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Naito M, Fujikura J, Ebihara K, Miyanaga F, Yokoi H, Kusakabe T, Yamamoto Y, Son C, Mukoyama M, Hosoda K, Nakao K. Therapeutic impact of leptin on diabetes, diabetic complications, and longevity in insulin-deficient diabetic mice. Diabetes 2011; 60:2265-73. [PMID: 21810600 PMCID: PMC3161331 DOI: 10.2337/db10-1795] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
OBJECTIVE The aim of the current study was to evaluate the long-term effects of leptin on glucose metabolism, diabetes complications, and life span in an insulin-dependent diabetes model, the Akita mouse. RESEARCH DESIGN AND METHODS We cross-mated Akita mice with leptin-expressing transgenic (LepTg) mice to produce Akita mice with physiological hyperleptinemia (LepTg:Akita). Metabolic parameters were monitored for 10 months. Pair-fed studies and glucose and insulin tolerance tests were performed. The pancreata and kidneys were analyzed histologically. The plasma levels and pancreatic contents of insulin and glucagon, the plasma levels of lipids and a marker of oxidative stress, and urinary albumin excretion were measured. Survival rates were calculated. RESULTS Akita mice began to exhibit severe hyperglycemia and hyperphagia as early as weaning. LepTg:Akita mice exhibited normoglycemia after an extended fast even at 10 months of age. The 6-h fasting blood glucose levels in LepTg:Akita mice remained about half the level of Akita mice throughout the study. Food intake in LepTg:Akita mice was suppressed to a level comparable to that in WT mice, but pair feeding did not affect blood glucose levels in Akita mice. LepTg:Akita mice maintained insulin hypersensitivity and displayed better glucose tolerance than did Akita mice throughout the follow-up. LepTg:Akita mice had normal levels of plasma glucagon, a marker of oxidative stress, and urinary albumin excretion rates. All of the LepTg:Akita mice survived for >12 months, the median mortality time of Akita mice. CONCLUSIONS These results indicate that leptin is therapeutically useful in the long-term treatment of insulin-deficient diabetes.
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Inuzuka M, Tamura N, Yamada N, Katsuura G, Oyamada N, Taura D, Sonoyama T, Fukunaga Y, Ohinata K, Sone M, Nakao K. C-type natriuretic peptide as a new regulator of food intake and energy expenditure. Endocrinology 2010; 151:3633-42. [PMID: 20555027 DOI: 10.1210/en.2010-0141] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The physiological implication of C-type natriuretic peptide (CNP) including energy metabolism has not been elucidated, because of markedly short stature in CNP-null mice. In the present study we analyzed food intake and energy expenditure of CNP-null mice with chondrocyte-targeted CNP expression (CNP-Tg/Nppc(-/-) mice), in which marked skeletal dysplasia was rescued, to investigate the significance of CNP under minimal influences of skeletal phenotypes. In CNP-Tg/Nppc(-/-) mice, body weight and body fat ratio were reduced by 24% and 32%, respectively, at 20 wk of age, and decreases of blood glucose levels during insulin tolerance tests were 2-fold exaggerated at 17 wk of age, as compared with CNP-Tg/Nppc(+/+) mice. Urinary noradrenalin excretion of CNP-Tg/Nppc(-/-) mice was greater than that of CNP-Tg/Nppc(+/+) mice by 28%. In CNP-Tg/Nppc(-/-) mice, rectal temperature at 1600 h was higher by 1.1 C, and uncoupling protein-1 mRNA expression in the brown adipose tissue was 2-fold increased, which was canceled by propranolol administration, as compared with CNP-Tg/Nppc(+/+) mice. Oxygen consumption was significantly increased in CNP-Tg/Nppc(-/-) mice compared with that in CNP-Tg/Nppc(+/+) mice. Food intake of CNP-Tg/Nppc(-/-) mice upon ad libitum feeding and refeeding after 48 h starvation were reduced by 21% and 61%, respectively, as compared with CNP-Tg/Nppc(+/+) mice. This study unveiled a new aspect of CNP as a molecule regulating food intake and energy expenditure. Further analyses on precise mechanisms of CNP actions would lead to the better understanding of the significance of the CNP/guanylyl cyclase-B system in food intake and energy expenditure.
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Affiliation(s)
- Megumi Inuzuka
- Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, Sakyo-ku, Kyoto 606-8507, Japan
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Nakao K, Yasoda A, Ebihara K, Hosoda K, Mukoyama M. Translational research of novel hormones: lessons from animal models and rare human diseases for common human diseases. J Mol Med (Berl) 2009; 87:1029-39. [DOI: 10.1007/s00109-009-0515-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2009] [Revised: 08/03/2009] [Accepted: 08/03/2009] [Indexed: 01/15/2023]
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20
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Masuzaki H, Tanaka T, Ebihara K, Hosoda K, Nakao K. Hypothalamic melanocortin signaling and leptin resistance--perspective of therapeutic application for obesity-diabetes syndrome. Peptides 2009; 30:1383-6. [PMID: 19394382 DOI: 10.1016/j.peptides.2009.04.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2009] [Revised: 04/13/2009] [Accepted: 04/14/2009] [Indexed: 11/25/2022]
Abstract
The adipocyte-derived hormone, leptin controls feeding behavior, augments fatty acid beta-oxidation in the skeletal muscle, attenuates insulin secretion but enhances whole body insulin sensitivity and glucose disposal, thereby serving as a promising therapeutic candidate for the treatment of insulin resistance and dyslipidemia. Along with other researchers, we demonstrated the clinical efficacy and safety of leptin in the treatment of diabetes and dyslipidemia for patients with generalized lipodystrophy. However, the clinical application of leptin has been hampered by the notion that leptin does not fully exert its metabolic effects in human obesity and diet-induced obese rodents. We found that the activity of skeletal muscle AMP-activated protein kinase (AMPK) parallels hypothalamic leptin sensitivity and metabolic phenotype in transgenic mice overexpressing leptin. Our data indicate that the activation of skeletal muscle AMPK is mediated by the hypothalamic melanocortin pathway. In fact, intracerebroventricular administration of melanocortin agonist, MT-II in mice robustly overcomes high-fat diet-induced leptin resistance and ameliorates fuel dyshomeostasis and hyperphagia, with a concomitant recovery of AMPK activity in skeletal muscle. Conversely, AMPK/ACC phosphorylation by leptin was abrogated by the co-administration of melanocortin antagonist, SHU9119 and in the KKA(y) mice, which centrally express endogenous melanocortin antagonist. Importantly, high-fat diet-induced attenuation of AMPK/ACC phosphorylation in leptin-overexpressing transgenic mice was not reversed by central leptin per se, but was markedly recovered by MT-II. Our data provide evidence for the critical role of the central melanocortin system in leptin-skeletal muscle AMPK axis, and highlight the system as a therapeutic target for leptin insuffciency in obese humans.
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Affiliation(s)
- Hiroaki Masuzaki
- Division of Endocrinology and Metabolism, Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, 54 Kawahara-cho Shogoin Sakyo-ku, Kyoto 606-8507, Japan.
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21
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Harada S, Fujita WH, Shichi K, Tokuyama S. The development of glucose intolerance after focal cerebral ischemia participates in subsequent neuronal damage. Brain Res 2009; 1279:174-81. [PMID: 19445903 DOI: 10.1016/j.brainres.2009.05.014] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2009] [Revised: 04/30/2009] [Accepted: 05/02/2009] [Indexed: 11/29/2022]
Abstract
Hyperglycemia is a known exacerbating factor in ischemic stroke; however, most information is limited to pre-ischemic hyperglycemia, while little is known about post-ischemic hyperglycemia. In addition, it has been clinically reported that hyperglycemia can develop after stroke, but the detailed mechanisms underlying this are unknown. Here, we focused on the relationship between post-ischemic hyperglycemia and the development of neuronal damage. In particular, we investigated the time course of alterations in fasting blood glucose levels (FBG) and the development of neuronal damage, including neuronal death (the development of infarction), behavioral abnormality and memory disturbance, using middle cerebral artery occlusion (MCAO) model mice. The neuronal death was observed from 6 h, reaching a maximum on day 3 and was gradually aggravated up to day 5 after MCAO. Interestingly, 12 h and 1 day after MCAO, FBG was significantly increased and insulin sensitivity and insulin secretory capacity were decreased on 1 day after MCAO. In addition, we found that the basal plasma insulin levels were significantly higher and adiponectin levels were significantly lower on day 1 in the MCAO group compared with the sham group. These results indicate that the development of glucose intolerance was observed on day 1. Importantly, the neuronal damage observed on day 3 was completely suppressed by continuous administration of insulin during the first 48 h after MCAO. These results suggest that the post-ischemic hyperglycemia in the early phase of ischemic stress may be involved in the development of neuronal damage.
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Affiliation(s)
- Shinichi Harada
- Department of Clinical Pharmacy, Kobe Gakuin University, Faculty of Pharmaceutical Sciences, Chuo-ku, Kobe, Japan
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22
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Niwano Y, Beppu F, Shimada T, Kyan R, Yasura K, Tamaki M, Nishino M, Midorikawa Y, Hamada H. Extensive screening for plant foodstuffs in Okinawa, Japan with anti-obese activity on adipocytes in vitro. PLANT FOODS FOR HUMAN NUTRITION (DORDRECHT, NETHERLANDS) 2009; 64:6-10. [PMID: 19067171 DOI: 10.1007/s11130-008-0102-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
To search for plant foodstuffs with potent anti-obese activity, we conducted a large scale screening based on the inhibitory activity on adipogenesis and the facilitating activity on adipolysis in vitro. That is, inhibition of intracellular lipid accumulation and facilitation of lipid degradation in 3T3-L1 adipocytes were extensively screened from ethanol and hexane extracts of approximately 100 kinds of plant foodstuffs marketed in Okinawa prefecture, which has been famous for the highest prevalence of exceptionally long-lived individuals in the world. Among them thirty one foodstuffs showed potent inhibitory activity on intracellular lipid accumulation in 3T3-L1 adipocytes, whereas only four foodstuffs showed clear facilitating effect on lipid degradation in 3T3-L1 adipocytes. Although further study to examine the in vivo effects on adipogenesis and adipolysis is required, this is the first study to investigate anti-obese characteristics of wide range of traditional Okinawa foodstuffs so that the results give useful information to take another look at Okinawa food culture.
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Affiliation(s)
- Yoshimi Niwano
- Research Center for Functional Food Materials, Sunny Health Holdings Co., Ltd., Saito Biotechnology Incubator, 7-7-15 Saito-Asagi, Ibaraki, Osaka, 567-0085, Japan.
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Motonaga C, Kondoh M, Hayashi A, Okamori M, Kitamura Y, Shimada T. Effect of Enterococcus faecalis FK-23 on Anti-obesity in Diet-induced Obesity Mice. J JPN SOC FOOD SCI 2009. [DOI: 10.3136/nskkk.56.541] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Yunoki K, Sasaki G, Tokuji Y, Kinoshita M, Naito A, Aida K, Ohnishi M. Effect of dietary wine pomace extract and oleanolic acid on plasma lipids in rats fed high-fat diet and its DNA microarray analysis. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2008; 56:12052-12058. [PMID: 19053393 DOI: 10.1021/jf8026217] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The aim of this study was to evaluate the concentration of oleanolic acids (OA) in pomace, a winemaking byproduct, and its influence on the levels of plasma lipids in rats fed a high-fat diet and on hepatic gene expression using DNA microarray analysis in vivo. HPLC analyses of pomace ethanol extract (PEE) revealed a high amount of OA ranging from 4 to 11 g/100 g. Male Sprague-Dawley rats were fed a normal-fat diet (NF group), a high-fat diet with 21% lard (HF group), a high-fat diet with 0.05% OA (OA group, 50 mg/kg/day), or a high-fat diet with 0.45% PEE (PEE group, 450 mg/kg/day). Plasma triacylglycerol and phospholipid concentrations were significantly lower in the OA and PEE groups than in the HF group. The microarray analysis of hepatic mRNA revealed reduced expression levels of lipogenic genes including acetyl-CoA carboxylase and glycerol-3-phosphate acyltransferase, probably resulting from the suppression of transcription factor Srebf1 expression. Gene expression of gluconeogensis and inflammatory cytokines was also down-regulated in the OA and PEE groups, suggesting that administration of OA or PEE could ameliorate obesity-induced insulin resistance, as well as prevent hyperlipidemia.
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Affiliation(s)
- Keita Yunoki
- Department of Agricultural and Life Science, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, Japan
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25
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Galletti F, D'Elia L, Barba G, Siani A, Cappuccio FP, Farinaro E, Iacone R, Russo O, De Palma D, Ippolito R, Strazzullo P. High-circulating leptin levels are associated with greater risk of hypertension in men independently of body mass and insulin resistance: results of an eight-year follow-up study. J Clin Endocrinol Metab 2008; 93:3922-6. [PMID: 18682500 DOI: 10.1210/jc.2008-1280] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
BACKGROUND We previously reported a significant association between plasma leptin (LPT) concentration and blood pressure (BP), which was partly independent of serum insulin levels and insulin resistance. The aims of this study were to detect whether serum LPT levels predict the development of hypertension (HPT) in the 8-yr follow-up investigation of a sample of an adult male population (the Olivetti Heart Study), and to evaluate the role of body mass index (BMI) and insulin resistance in this putative association. PATIENTS AND METHODS The study population was made up of 489 untreated normotensive subjects examined in 1994-1995 (age: 50.1 +/- 6.7 yr; BMI: 26.3 +/- 2.8 kg/m(2); BP: 120 +/- 10/78 +/- 6 mm Hg; and homeostatic model assessment index: 2.1 +/- 1.6). RESULTS The HPT incidence over 8 yr was 35%. The participants with incident HPT had similar age but higher BMI (P < 0.001), serum LPT (P < 0.001), and BP (P < 0.01) at baseline. One sd positive difference in baseline serum LPT log was associated at univariate analysis with a 49% higher rate of HPT [95% confidence interval (CI) 22-83; P < 0.001]). In three different models of multivariable logistical regression analysis, LPT was respectively associated with a 41% greater risk to develop HPT (95% CI 15-74; P < 0.001) upon adjustment for age and baseline BP, with a 48% (95% CI 20-81) greater risk when adding the homeostatic assessment model index to the model, and with 33% greater risk (95% CI 6-67; P < 0.02) upon adjustment for BMI. CONCLUSIONS In this sample of originally normotensive men, circulating LPT level was a significant predictor of the risk to develop HPT over 8 yr, independently of BMI and insulin resistance.
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Affiliation(s)
- F Galletti
- Department of Clinical and Experimental Medicine, Federico II University Medical School, Via S. Pansini, 5, 80131 Naples, Italy.
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26
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Townsend KL, Lorenzi MM, Widmaier EP. High-fat diet-induced changes in body mass and hypothalamic gene expression in wild-type and leptin-deficient mice. Endocrine 2008; 33:176-88. [PMID: 18483882 DOI: 10.1007/s12020-008-9070-1] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2008] [Revised: 03/28/2008] [Accepted: 04/25/2008] [Indexed: 10/22/2022]
Abstract
We tested whether diet-induced obesity results from increased energy consumption, is associated with changes in expression of genes involved in leptin signal transduction, and is altered by hyperleptinemia. C57BL/6 mice were fed a low-fat diet (LFD) or high-fat diet (HFD) for up to 15 weeks. HFD mice weighed significantly more than LFD controls by 3 weeks, despite consuming less energy. HFD mice had significantly greater leptin, insulin, and glucose levels than LFD mice, suggesting leptin and insulin resistance. Adiponectin levels declined with age but were unaffected by diet. HFD was associated with altered hypothalamic expression of genes whose products regulate the activity or nuclear translocation of STAT3, an important mediator of leptin actions. Expression of two isoforms of the leptin receptor decreased at 15 weeks in hypothalami of HFD mice in a tissue-specific manner. The type of fat (saturated versus unsaturated) did not influence weight gain on an HFD, but animals on LFD gained significantly more weight and adiposity if the dietary fat consisted mostly of saturated fats; this occurred despite no difference in energy consumption or absorption. Replacement of leptin to leptin-deficient ob/ob mice decreased hypothalamic leptin receptor expression and did not prevent HFD-induced weight gain. It is concluded that (1) increased energy consumption is not required for HFD-induced obesity in C57BL/6 mice, (2) HFD results in weight gain partly by modulating hypothalamic leptin-signaling pathways, (3) saturated fats induce weight gain even when total fat content of the diet is low, and (4) the effects of HFD are manifest in the presence or absence of circulating leptin.
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Affiliation(s)
- Kristy L Townsend
- Department of Biology, Boston University, 5 Cummington Street, Boston, MA 02215, USA
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27
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Holden KF, Lindquist K, Tylavsky FA, Rosano C, Harris TB, Yaffe K. Serum leptin level and cognition in the elderly: Findings from the Health ABC Study. Neurobiol Aging 2008; 30:1483-9. [PMID: 18358569 DOI: 10.1016/j.neurobiolaging.2007.11.024] [Citation(s) in RCA: 159] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2007] [Revised: 11/18/2007] [Accepted: 11/20/2007] [Indexed: 11/19/2022]
Abstract
Leptin is a peptide hormone secreted by adipocytes. It has been shown to modulate production and clearance of amyloid beta (Abeta) in rodent models. We sought to determine if serum leptin was associated with cognitive decline in the elderly. We studied 2871 well-functioning elders, aged 70-79, who were enrolled in a prospective study. Serum leptin concentrations were measured at baseline and analyzed by mean+/-1S.D. Clinically significantly cognitive decline over 4 years was defined as > or =5-point drop on the Modified Mini Mental State Exam (3MS). Compared to those in the lower leptin groups, elders in the high leptin group had less cognitive decline, 20.5% versus 24.7% (OR=0.79; 95% CI 0.61-1.02, p=0.07). After adjustment for demographic and clinical variables, including body mass index and total percent body fat, those in the high leptin group had significantly less likelihood of cognitive decline, OR=0.66 (95% CI 0.48-0.91). We conclude that in elderly individuals, higher serum leptin appears to protect against cognitive decline, independent of comorbidites and body fat.
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Affiliation(s)
- Karen F Holden
- Department of Psychiatry, University of California San Francisco, 94143, USA.
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28
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Okano K, Ohba T, Matsugami K, Uchida K, Nitta K, Kabaya T. Analysis of plasma adipocytokines related to clinical and laboratory data in the maintenance hemodialysis patients. Intern Med 2008; 47:1379-86. [PMID: 18670142 DOI: 10.2169/internalmedicine.47.1145] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND Atherosclerotic vascular diseases such as cerebrovascular and cardiovascular diseases are major causes for fatality of hemodialysis (HD) patients. Since adipocytokines are key players for arteriosclerosis in the concept of metabolic syndrome (MetS), we aimed to determine whether circulating levels of major three adipocytokines, adiponectin, TNF-alpha, and leptin, could be associated with various parameters and clinical events in HD patients who are diagnosed as MetS using a new criteria designed for the Japanese population. PATIENTS AND METHODS We enrolled 53 very stable patients under maintenance HD at Minami-Senju Hospital. Basically, clinical and laboratory data were taken just before HD therapy. HD sessions were performed regularly and all the participants took oral administration and injection as usual. A cross-sectional study was performed to evaluate clinical and laboratory data related to three major adipocytokines, adiponectin, TNF-alpha and leptin. RESULTS We observed no significant differences of three adipocytokines when the participants were divided in accordance with existence of MetS or past cerebrocascular/cardiovascular diseases. Only the serum adiponectin levels were significantly different in two groups categorized by existence of diabetes mellitus. Serum triglycerides (TG) were significantly correlated with two circulating adipocytokines, adiponectin (r=-0.328, p<0.016) and leptin (r=0.397, p<0.003), when we analyzed all 53 patients together. CONCLUSION Plasma adiponectin and leptin are expected as contributors related to dyslipidemia, suggesting these may be targets of prevention of vascular diseases in maintenance HD patients.
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Affiliation(s)
- Kazuhiro Okano
- Department of Medicine, Kidney Center, Tokyo Women's Medical University.
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29
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Huang PH, Sata M, Nishimatsu H, Sumi M, Hirata Y, Nagai R. Pioglitazone ameliorates endothelial dysfunction and restores ischemia-induced angiogenesis in diabetic mice. Biomed Pharmacother 2008; 62:46-52. [PMID: 17692499 DOI: 10.1016/j.biopha.2007.06.014] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2007] [Accepted: 06/20/2007] [Indexed: 10/23/2022] Open
Abstract
Angiogenesis, the formation of new blood vessels, is a physiological response to tissue ischemia. Clinical evidence suggests that diabetic patients have endothelial dysfunction and impaired angiogenesis in response to ischemia. Here, we investigated the impact of diabetes on ischemia-induced collateral growth, and tested the hypothesis that peroxisome proliferator-activated receptor-gamma (PPARgamma) agonist augments collateral flow to ischemic tissue. We conducted unilateral hindlimb ischemia surgery in KKAy mice. Blood flow recovery was markedly impaired in diabetic mice compared with that in wild-type mice as determined by laser Doppler imaging. Treatment of KKAy mice with pioglitazone partially restored the blood flow recovery. Anti-CD31 immunostaining revealed that pioglitazone also significantly improved the capillary density in ischemic limb muscle. Endothelial NO synthase (eNOS) activity was ameliorated in diabetic mice treated with pioglitazone as determined by vasorelaxation in response to acetylcholine. Pioglitazone normalized vascular endothelial growth factor (VEGF) protein levels, which was decreased in ischemic muscle of KKAy mice, and up-regulated eNOS phosphorylation at Ser-1177 and Akt phosphorylation at Ser-473 in ischemic muscle. Pioglitazone had no beneficial effects on blood flow recovery in diabetic mice treated with N(G)-nitro-l-arginine methyl ester (L-NAME). Our findings demonstrate that pioglitazone significantly ameliorates endothelial dysfunction and enhances blood flow recovery after tissue ischemia in diabetic mice. Activation of eNOS appears to be essential for pioglitazone to promote angiogenesis in ischemic tissue.
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Affiliation(s)
- Po-Hsun Huang
- Department of Cardiovascular Medicine, University of Tokyo, Graduate School of Medicine, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan
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Central leptin insufficiency syndrome: an interactive etiology for obesity, metabolic and neural diseases and for designing new therapeutic interventions. Peptides 2007; 29:127-38. [PMID: 18053615 DOI: 10.1016/j.peptides.2007.10.017] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2007] [Revised: 10/17/2007] [Accepted: 10/18/2007] [Indexed: 01/10/2023]
Abstract
This review critically reappraises recent scientific evidence concerning central leptin insufficiency versus leptin resistance formulations to explain metabolic and neural disorders resulting from subnormal or defective leptin signaling in various sites in the brain. Research at various fronts to unravel the complexities of the neurobiology of leptin is surveyed to provide a comprehensive account of the neural and metabolic effects of environmentally imposed fluctuations in leptin availability at brain sites and the outcome of newer technology to restore leptin signaling in a site-specific manner. The cumulative new knowledge favors a unified central leptin insufficiency syndrome over the, in vogue, central resistance hypothesis to explain the global adverse impact of deficient leptin signaling in the brain. Furthermore, the leptin insufficiency syndrome delineates a novel role of leptin in the hypothalamus in restraining rhythmic pancreatic insulin secretion while concomitantly enhancing glucose metabolism and non-shivering thermogenic energy expenditure, sequelae that would otherwise promote fat accrual to store excess energy resulting from consumption of energy-enriched diets. A concerted effort should now focus on development of newer technologies for delivery of leptin or leptin mimetics to specifically target neural pathways for remediation of diverse ailments encompassing the central leptin insufficiency syndrome.
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Maeda H, Hosokawa M, Sashima T, Miyashita K. Dietary combination of fucoxanthin and fish oil attenuates the weight gain of white adipose tissue and decreases blood glucose in obese/diabetic KK-Ay mice. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2007; 55:7701-6. [PMID: 17715888 DOI: 10.1021/jf071569n] [Citation(s) in RCA: 192] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Fucoxanthin is a marine carotenoid found in edible brown seaweeds. We previously reported that dietary fucoxanthin attenuates the weight gain of white adipose tissue (WAT) of diabetic/obese KK- A(y) mice. In this study, to evaluate the antiobesity and antidiabetic effects of fucoxanthin and fish oil, we investigated the effect on the WAT weight, blood glucose, and insulin levels of KK- A(y) mice. Furthermore, the expression level of uncoupling protein 1 (UCP1) and adipokine mRNA in WAT were measured. After 4 weeks of feeding, 0.2% fucoxanthin in the diet markedly attenuated the gain of WAT weight in KK- A(y) mice with increasing UCP1 expression compared with the control mice. The WAT weight of the mice fed 0.1% fucoxanthin and 6.9% fish oil was also significantly lower than that of the mice fed fucoxanthin alone. In addition, 0.2% fucoxanthin markedly decreased the blood glucose and plasma insulin concentrations in KK- A(y) mice. The mice fed with the combination diet of 0.1% fucoxanthin and fish oil also showed improvements similar to that of 0.2% fucoxanthin. Leptin and tumor necrosis factor (TNFalpha) mRNA expression in WAT were significantly down-regulated by 0.2% fucoxanthin. These results suggest that dietary fucoxanthin decreases the blood glucose and plasma insulin concentration of KK- A(y) along with down-regulating TNFalpha mRNA. In addition, the combination of fucoxanthin and fish oil is more effective for attenuating the weight gain of WAT than feeding with fucoxanthin alone.
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Affiliation(s)
- Hayato Maeda
- Faculty of Fisheries Sciences, Hokkaido University, 3-1-1 Minato, Hakodate, Hokkaido 041-8611, Japan
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Ihara S, Shimamoto K, Watanabe H, Sakai R, Kawana M. An alpha1-receptor blocker reduces plasma leptin levels in hypertensive patients with obesity and hyperleptinemia. Hypertens Res 2007; 29:805-11. [PMID: 17283868 DOI: 10.1291/hypres.29.805] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Obesity is often complicated by hypertension, and both conditions are risk factors for atherosclerosis. Leptin has attracted attention as a possible cause of hypertension in obese persons. We investigated the effect of a slow-release alpha1-receptor blocker, bunazosin hydrochloride, on leptin levels and insulin resistance in obese hypertensive patients with hyperleptinemia. The subjects were 17 patients (12 men and 5 women aged 56.1 +/- 12.2 years) with essential hypertension who were not receiving alpha1-receptor blockers. They had a body mass index (BMI) > or = 25 kg/m2 and a plasma leptin concentration > or = 5 ng/ml. They received oral therapy with bunazosin hydrochloride at doses of up to 9 mg/day. The plasma leptin concentration, body weight, blood pressure, heart rate, fasting blood glucose, plasma insulin concentration, and free fatty acid level were compared between before and after treatment. Although there was no significant change of BMI, there was a significant decrease of plasma leptin after treatment (10.6 +/- 5.4 ng/ml vs. 8.7 +/- 3.4 ng/ml, p = 0.0128), as well as a significant decrease of plasma insulin (9.8 +/- 4.8 microU/ml vs. 8.1 +/- 4.6 microU/ml, p = 0.0494) and HOMA-R (2.9 +/- 2.1 vs. 2.2 +/- 1.5, p = 0.0237). In conclusion, bunazosin hydrochloride reduced the plasma leptin level and improved insulin resistance in hypertensive patients with obesity and hyperleptinemia.
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Affiliation(s)
- Shunichi Ihara
- Department of Cardiology, Aoyama Hospital, Tokyo Women's Medical University, Japan
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Wright WS, Longo KA, Dolinsky VW, Gerin I, Kang S, Bennett CN, Chiang SH, Prestwich TC, Gress C, Burant CF, Susulic VS, MacDougald OA. Wnt10b inhibits obesity in ob/ob and agouti mice. Diabetes 2007; 56:295-303. [PMID: 17259372 DOI: 10.2337/db06-1339] [Citation(s) in RCA: 138] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The Wnt family of secreted signaling molecules has profound effects on diverse developmental processes, including the fate of mesenchymal progenitors. While activation of Wnt signaling blocks adipogenesis, inhibition of endogenous Wnt/beta-catenin signaling by Wnt10b promotes spontaneous preadipocyte differentiation. Transgenic mice with expression of Wnt10b from the FABP4 promoter (FABP4-Wnt10b) have less adipose tissue when maintained on a normal chow diet and are resistant to diet-induced obesity. Here we demonstrate that FABP4-Wnt10b mice largely avert weight gain and metabolic abnormalities associated with genetic obesity. FABP4-Wnt10b mice do not gain significant body weight on the ob/ob background, and at 8 weeks of age, they have an approximately 70% reduction in visceral and subcutaneous adipose tissues compared with ob/ob mice. Similarly, on the lethal yellow agouti (A(y)) background, FABP4-Wnt10b mice have 50-70% less adipose tissue weight and circulating leptin at 5 months of age. Wnt10b-Ay mice are more glucose tolerant and insulin sensitive than A(y) controls, perhaps due to reduced expression and circulation of resistin. Reduced expression of inflammatory cytokines may also contribute to improved glucose homeostasis.
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Affiliation(s)
- Wendy S Wright
- Department of Molecular and Integrative Physiology, University of Michigan, 1301 E. Catherine Drive, Ann Arbor, MI 48109-0622, USA
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Unno Y, Akuta T, Sakamoto YI, Horiuchi S, Akaike T. Nitric oxide-induced downregulation of leptin production by 3T3-L1 adipocytes. Nitric Oxide 2006; 15:125-32. [PMID: 16442319 DOI: 10.1016/j.niox.2005.12.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2005] [Revised: 11/21/2005] [Accepted: 12/10/2005] [Indexed: 02/06/2023]
Abstract
Leptin secreted mainly by adipocytes plays an important role in insulin sensitivity in metabolic syndrome. Inducible nitric oxide synthase (iNOS) in 3T3-L1 adipocytes is induced by lipopolysaccharide (LPS) and several proinflammatory cytokines such as tumor necrosis factor-alpha and interferon-gamma (IFN-gamma). Because the role of iNOS-derived nitric oxide (NO) in adipocyte function has not been fully clarified, the question that we addressed in the present study was whether iNOS-derived NO is involved in regulation of leptin secretion by adipocytes. Incubation of 3T3-L1 adipocytes for 12h with a mixture of IFN-gamma and LPS caused not only a 55% reduction in leptin secretion and a 52% reduction in leptin mRNA, but also significant induction of iNOS at both protein and mRNA levels. Inhibition of leptin secretion that had been induced by the IFN-gamma-LPS mixture was completely nullified by NOS inhibitors such as Nomega-monomethyl-L-arginine and aminoguanidine. Treatment of adipocytes with NO donors such as an NONOate and S-nitrosoglutathione produced an effect on leptin secretion similar to that of the IFN-gamma-LPS mixture. It is likely therefore that NO mediates downregulation of leptin caused by the IFN-gamma-LPS mixture in 3T3-L1 adipocytes, which suggests an important role for NO in adipocyte functions.
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Affiliation(s)
- Yuka Unno
- Department of Microbiology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
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Ohashi K, Kihara S, Ouchi N, Kumada M, Fujita K, Hiuge A, Hibuse T, Ryo M, Nishizawa H, Maeda N, Maeda K, Shibata R, Walsh K, Funahashi T, Shimomura I. Adiponectin replenishment ameliorates obesity-related hypertension. Hypertension 2006; 47:1108-16. [PMID: 16651465 DOI: 10.1161/01.hyp.0000222368.43759.a1] [Citation(s) in RCA: 256] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Patients with obesity are susceptible to hypertension. We have reported that the plasma adiponectin levels are decreased in obesity and that adiponectin has many defensive properties against obesity-related diseases, such as type 2 diabetes and coronary artery disease. The aim of this study was to determine the relationship between adiponectin and hypertension in mice. We measured blood pressure and heart rate directly by a catheter in the carotid artery and indirectly by automatic sphygmomanometer at the tail artery. Obese KKAy mice had significantly lower plasma adiponectin levels and higher systolic blood pressure than control C57BL/6J mice at 21 weeks of age. Adenovirus-delivered adiponectin significantly decreased blood pressure in KKAy mice. The direct role of adiponectin on blood pressure regulation under insulin resistance-free state was investigated in adiponectin-knockout (KO) mice. Adiponectin KO mice developed hypertension when maintained on a high-salt diet (8% NaCl) without insulin resistance. The hypertension of salt-fed adiponectin KO mice was associated with reduced mRNA levels of endothelial NO synthase (eNOS) and prostaglandin I(2) synthase in aorta and low metabolite levels of endothelial NO synthase and prostaglandin I(2) synthase in plasma. Adiponectin therapy lowered the elevated blood pressure and corrected the above mRNA levels to those of the wild type. Our results suggest that hypoadiponectinemia contributes to the development of obesity-related hypertension, at least in part, directly, in addition to its effect via insulin resistance, and that adiponectin therapy can be potentially useful for hypertension in patients with the metabolic syndrome.
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Affiliation(s)
- Koji Ohashi
- Department of Metabolic Medicine, Graduate School of Medicine, Osaka University, Osaka, Japan
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Nakano M, Hamada T, Hayashi T, Yonemitsu S, Miyamoto L, Toyoda T, Tanaka S, Masuzaki H, Ebihara K, Ogawa Y, Hosoda K, Inoue G, Yoshimasa Y, Otaka A, Fushiki T, Nakao K. α2 isoform-specific activation of 5'adenosine monophosphate-activated protein kinase by 5-aminoimidazole-4-carboxamide-1-β-D-ribonucleoside at a physiological level activates glucose transport and increases glucose transporter 4 in mouse skeletal muscle. Metabolism 2006; 55:300-8. [PMID: 16483872 DOI: 10.1016/j.metabol.2005.09.003] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2004] [Accepted: 09/24/2005] [Indexed: 01/22/2023]
Abstract
5'Adenosine monophosphate-activated protein kinase (AMPK) has been implicated in exercise-induced stimulation of glucose metabolism in skeletal muscle. Although skeletal muscle expresses both the alpha1 and alpha2 isoforms of AMPK, the alpha2 isoform is activated predominantly in response to moderate-intensity endurance exercise in human and animal muscles. The purpose of this study was to determine whether activation of alpha2 AMPK plays a role in increasing the rate of glucose transport, promoting glucose transporter 4 (GLUT4) expression, and enhancing insulin sensitivity in skeletal muscle. To selectively activate the alpha2 isoform, we used 5-aminoimidazole-4-carboxamide-1-beta-d-ribonucleoside (AICAR), which is metabolized in muscle cells and preferentially stimulates the alpha2 isoform. Subcutaneous administration of 250 mg/kg AICAR activated the alpha2 isoform for 90 minutes, but not the alpha1 isoform in hind limb muscles of the C57/B6J mouse. The maximal activation of the alpha2 isoform was observed 30 to 60 minutes after administration of AICAR and was similar to the activation induced by a 30-minute swim in a current pool. The increase in alpha2 activity paralleled the phosphorylation of Thr(172), the essential residue for full kinase activation, and the activity of acetyl-coenzyme A carboxylase beta, a known substrate of AMPK in skeletal muscle. Subcutaneous injection of AICAR rapidly increased, by 30%, the rate of 2-deoxyglucose (2DG) transport into soleus muscle; 2DG transport increased within 30 minutes and remained elevated for 4 hours after administration of AICAR. Repeated intraperitoneal injection of AICAR, 3 times a day for 4 to 7 days, increased soleus GLUT4 protein by 30% concomitant with a significant 20% increase in insulin-stimulated 2DG transport. These data suggest that moderate endurance exercise promotes glucose transport, GLUT4 expression, and insulin sensitivity in skeletal muscle at least partially via activation of the alpha2 isoform of AMPK.
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Affiliation(s)
- Masako Nakano
- Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan
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Amamoto T, Kumai T, Nakaya S, Matsumoto N, Tsuzuki Y, Kobayashi S. The Elucidation of the Mechanism of Weight Gain and Glucose Tolerance Abnormalities Induced by Chlorpromazine. J Pharmacol Sci 2006; 102:213-9. [PMID: 17031068 DOI: 10.1254/jphs.fp0060673] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
Antipsychotic drugs induce weight gain and metabolic abnormalities. Recently, the role of adipocytokines secreted from adipocytes in the development of metabolic syndrome has received attention. The aim of this study was to investigate the effects of chlorpromazine (Cp) on body weight, glucose, lipid metabolism, and adipocytokine secretion in rats fed sucrose. Wistar rats received 15% sucrose (Suc group), 15% sucrose and Cp at 7.5 mg/kg per day (Suc + Cp group), or Cp alone (Cp group) in water for 10 weeks. Fasting glucose levels in the Suc and Suc + Cp groups were significantly higher than in the control (Cont) group. Fasting insulin levels in the Suc, Suc + Cp, and Cp groups were also significantly higher than in the Cont group. The adiponectin level in the Suc group was significantly higher than in the Cont group, although the adiponectin level in the Suc + Cp group was not. Furthermore, the plasma tumor necrosis factor (TNF)-alpha level in the Suc + Cp group was significantly higher than in the Suc group. These data suggest that Cp inhibits the compensatory response of adiponectin with respect to obesity due to increased expression of plasma TNF-alpha level. Cp may exert more harmful effects on the glucose level and insulin resistance than on other factors, which may be one of the mechanisms responsible for the metabolic syndrome induced by antipsychotic agents.
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Affiliation(s)
- Takahiro Amamoto
- Department of Pharmacology, St. Marianna University School of Medicine, Japan
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38
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Toyoshima Y, Gavrilova O, Yakar S, Jou W, Pack S, Asghar Z, Wheeler MB, LeRoith D. Leptin improves insulin resistance and hyperglycemia in a mouse model of type 2 diabetes. Endocrinology 2005; 146:4024-35. [PMID: 15947005 DOI: 10.1210/en.2005-0087] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Leptin has metabolic effects on peripheral tissues including muscle, liver, and pancreas, and it has been successfully used to treat lipodystrophic diabetes, a leptin-deficient state. To study whether leptin therapy can be used for treatment of more common cases of type 2 diabetes, we used a mouse model of type 2 diabetes (MKR mice) that show normal leptin levels and are diabetic due to a primary defect in both IGF-I and insulin receptors signaling in skeletal muscle. Here we show that leptin administration to the MKR mice resulted in improvement of diabetes, an effect that was independent of the reduced food intake. The main effect of leptin therapy was enhanced hepatic insulin responsiveness possibly through decreasing gluconeogenesis. In addition, the reduction of lipid stores in liver and muscle induced by enhancing fatty acid oxidation and inhibiting lipogenesis led to an improvement of the lipotoxic condition. Our data suggest that leptin could be a potent antidiabetic drug in cases of type 2 diabetes that are not leptin resistant.
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Affiliation(s)
- Yuka Toyoshima
- Diabetes Branch, National Institute of Diabetes and Digestive and Kidney Diseases, Room 8D12, Building 10, MSC 1758, National Institutes of Health, Bethesda, Maryland 20892-1758, USA
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Tanaka T, Hidaka S, Masuzaki H, Yasue S, Minokoshi Y, Ebihara K, Chusho H, Ogawa Y, Toyoda T, Sato K, Miyanaga F, Fujimoto M, Tomita T, Kusakabe T, Kobayashi N, Tanioka H, Hayashi T, Hosoda K, Yoshimatsu H, Sakata T, Nakao K. Skeletal muscle AMP-activated protein kinase phosphorylation parallels metabolic phenotype in leptin transgenic mice under dietary modification. Diabetes 2005; 54:2365-74. [PMID: 16046303 DOI: 10.2337/diabetes.54.8.2365] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Leptin augments glucose and lipid metabolism independent of its effect on satiety. Administration of leptin in rodents increases skeletal muscle beta-oxidation by activating AMP-activated protein kinase (AMPK). We previously reported that, as hyperleptinemic as obese human subjects, transgenic skinny mice overexpressing leptin in liver (LepTg) exhibit enhanced insulin sensitivity and lipid clearance. To assess skeletal muscle AMPK activity in leptin-sensitive and -insensitive states, we examined phosphorylation of AMPK and its target, acetyl CoA carboxylase (ACC), in muscles from LepTg under dietary modification. Here we show that phosphorylation of AMPK and ACC are chronically augmented in LepTg soleus muscle, with a concomitant increase in the AMP-to-ATP ratio and a significant decrease in tissue triglyceride content. Despite preexisting hyperleptinemia, high-fat diet (HFD)-fed LepTg develop obesity, insulin-resistance, and hyperlipidemia. In parallel, elevated soleus AMPK and ACC phosphorylation in regular diet-fed LepTg is attenuated, and tissue triglyceride content is increased in those given HFD. Of note, substitution of HFD with regular diet causes a robust recovery of soleus AMPK and ACC phosphorylation in LepTg, with a higher rate of body weight reduction and a regain of insulin sensitivity. In conclusion, soleus AMPK and ACC phosphorylation in LepTg changes in parallel with its insulin sensitivity under dietary modification, suggesting a close association between skeletal muscle AMPK activity and sensitivity to leptin.
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Affiliation(s)
- Tomohiro Tanaka
- Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawaharacho, Sakyo-ku, Kyoto 606-8507, Japan
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Yotsumoto T, Naitoh T, Kanaki T, Tsuruzoe N. A retinoid X receptor antagonist, HX531, improves leptin resistance without increasing plasma leptin level in KK-Ay mice under normal dietary conditions. Metabolism 2005; 54:573-8. [PMID: 15877285 DOI: 10.1016/j.metabol.2004.11.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
4-(5 H -2,3-(2,5-Dimethyl-2,5-hexano)-5-methyl-8-nitrodibenzo[b,e][1,4]diazepin-11-yl)benzoic acid (HX531) is a novel retinoid X receptor antagonist. This study provides evidence that HX531 improves leptin resistance without increasing plasma leptin levels in KK-A y mice, an animal model with high plasma leptin levels and leptin resistance. Under normal dietary conditions, 3 weeks of treatment with HX531 (0.03% and 0.06% food admixture) in KK-A y mice decreased plasma leptin levels in a dose- and time-dependent manner, in addition to decreasing body weight and mesenteric fatty tissue weight. To evaluate the effect of HX531 on leptin resistance, leptin was injected intraperitoneally in the KK-A y mice for 4 days after 1 week of treatment with HX531 (0.06% food admixture). This pretreatment with HX531 resulted in exogenously administered leptin causing a significant decrease in food intake. These results suggested that HX531 decreased plasma leptin levels accompanied by a decrease in fatty tissue content in the KK-A y mice and a simultaneous improvement in leptin resistance. This is the first report that HX531 improves leptin resistance without increasing plasma leptin level in KK-A y mice, under normal dietary conditions.
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Affiliation(s)
- Takashi Yotsumoto
- Biological research Laboratories, Nissan Chemical Industries Ltd., Saitama 349-0294, Japan.
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41
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Unno Y, Sakai M, Sakamoto YI, Kuniyasu A, Nakayama H, Nagai R, Horiuchi S. Advanced glycation end products-modified proteins and oxidized LDL mediate down-regulation of leptin in mouse adipocytes via CD36. Biochem Biophys Res Commun 2004; 325:151-6. [PMID: 15522213 DOI: 10.1016/j.bbrc.2004.10.015] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2004] [Indexed: 11/18/2022]
Abstract
Advanced glycation end products (AGE)-modified proteins as well as oxidized-LDL (Ox-LDL) undergo receptor-mediated endocytosis by CHO cells overexpressing CD36, a member of class B scavenger receptor family. The purpose of the present study was to examine the effects of glycolaldehyde-modified BSA (GA-BSA) as an AGE-ligand and Ox-LDL on leptin expression in adipocytes. GA-BSA decreased leptin expression at both protein and mRNA levels in 3T3-L1 adipocytes and mouse epididymal adipocytes. Ox-LDL showed a similar inhibitory effect on leptin expression in 3T3-L1 adipocytes, which effect was protected by N-acetylcysteine, a reactive oxygen species (ROS) inhibitor. Binding of (125)I-GA-BSA or (125)I-Ox-LDL to 3T3-L1 adipocytes and subsequent endocytic degradation were inhibited by a neutralizing anti-CD36 antibody. Furthermore, this antibody also suppressed Ox-LDL-induced leptin down-regulation. These results clarify that the interaction of GA-BSA and Ox-LDL with CD36 leads to down-regulation of leptin expression via ROS system(s) in 3T3-L1 adipocytes, suggesting that a potential link of AGE- and/or Ox-LDL-induced leptin down-regulation might be linked to insulin-sensitivity in metabolic syndrome.
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Affiliation(s)
- Yuka Unno
- Department of Medical Biochemistry, Graduate School of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
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Suganami T, Mukoyama M, Mori K, Yokoi H, Koshikawa M, Sawai K, Hidaka S, Ebihara K, Tanaka T, Sugawara A, Kawachi H, Vinson C, Ogawa Y, Nakao K. Prevention and reversal of renal injury by leptin in a new mouse model of diabetic nephropathy. FASEB J 2004; 19:127-9. [PMID: 15496495 DOI: 10.1096/fj.04-2183fje] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Diabetic nephropathy is the leading cause of end-stage renal disease, for which effective therapy to prevent the progression at advanced stages remains to be established. There is also a long debate whether diabetic glomerular injury is reversible or not. Lipoatrophic diabetes, a syndrome caused by paucity of adipose tissue, is characterized by severe insulin resistance, dyslipidemia, and fatty liver. Here, we show that a genetic model of lipoatrophic diabetes (A-ZIP/F-1 mice) manifests a typical renal injury observed in human diabetic nephropathy that is associated with glomerular hypertrophy, diffuse and pronounced mesangial widening, accumulation of extracellular matrix proteins, podocyte damage, and overt proteinuria. By crossing A-ZIP/F-1 mice with transgenic mice overexpressing an adipocyte-derived hormone leptin, we also reveal that leptin completely prevents the development of hyperglycemia and nephropathy in A-ZIP/F-1 mice. Furthermore, continuous leptin administration to A-ZIP/F-1 mice by minipump beginning at 40 weeks of age significantly alleviates the glomerular injury and proteinuria. These findings demonstrate the therapeutic usefulness of leptin at least for a certain type of diabetic nephropathy. The model presented here will serve as a novel tool to analyze the molecular mechanism underlying not only the progression but also the regression of diabetic nephropathy.
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Affiliation(s)
- Takayoshi Suganami
- Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, Kyoto, Japan
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43
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Oktem O, Dedeoğlu N, Oymak Y, Sezen D, Köksal L, Pekin T, Gökaslan H, Kavak ZN. Maternal serum, amniotic fluid and cord leptin levels at term: their correlations with fetal weight. J Perinat Med 2004; 32:266-71. [PMID: 15188803 DOI: 10.1515/jpm.2004.050] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AIMS To investigate the relationship between fetal weight and leptin levels in maternal serum, amniotic fluid and umbilical cord. METHODS Forty pregnant women presenting for antenatal care at early weeks of gestation were enrolled for the study. Maternal and cord blood samples for leptin measurement were obtained at birth. Amniotic fluid samples were recovered by amniotomy performed during labor. Maternal body mass index and placental weight were also recorded. Leptin measurement was carried out using the ELISA method. Spearman's correlation test was used for comparison of non-parametric data. RESULTS Leptin concentration in venous cord blood correlated significantly with birth weight and placental weight whereas maternal serum and amniotic fluid leptin levels did not show correlation with birth weight. There were no significant correlations between leptin levels in maternal serum, cord blood and amniotic fluid. CONCLUSION We conclude that lack of correlation between leptin levels in mother, cord and amniotic fluid suggest that these compartments may be non-communicating separate units or have different mechanisms regulating leptin synthesis or degradation, and that leptin in maternal blood and amniotic fluid may not have a direct effect on fetal growth but rather a different role in pregnancy.
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Affiliation(s)
- Ozgür Oktem
- Center for Reproductive Medicine and Infertility, Weill Medical College of Cornell University, New York, NY 10021, USA.
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Hazel M, Cooksey RC, Jones D, Parker G, Neidigh JL, Witherbee B, Gulve EA, McClain DA. Activation of the hexosamine signaling pathway in adipose tissue results in decreased serum adiponectin and skeletal muscle insulin resistance. Endocrinology 2004; 145:2118-28. [PMID: 14684615 DOI: 10.1210/en.2003-0812] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Overexpression of the rate-limiting enzyme for hexosamine synthesis (glutamine:fructose-6-phosphate amidotransferase) in muscle and adipose tissue of transgenic mice was previously shown to result in insulin resistance and hyperleptinemia. Explanted muscle from transgenic mice was not insulin resistant in vitro, suggesting that muscle insulin resistance could be mediated by soluble factors from fat tissue. To dissect the relative contributions of muscle and fat to hexosamine-induced insulin resistance, we overexpressed glutamine:fructose-6-phosphate amidotransferase 2.5-fold, specifically in fat under control of the aP2 promoter. Fasting glucose, insulin, and triglycerides were unchanged in the transgenic mice; leptin and beta-hydroxybutyrate levels were 91% and 29% higher, respectively. Fasted transgenic mice have mild glucose intolerance and skeletal muscle insulin resistance in vivo. In fasting transgenic mice, glucose disposal rates with hyperinsulinemia were decreased 27% in females and 10% in males. Uptake of 2-deoxy-D-glucose into muscle was diminished by 45% in female and 21% in male transgenics. Serum adiponectin was also lower in the fasted transgenics, by 37% in females and 22% in males. TNF alpha and resistin mRNA levels in adipose tissue were not altered in the fasted transgenics; levels of mRNA for leptin were increased and peroxisome proliferator-activated receptor gamma decreased. To further explore the relationship between adiponectin and insulin sensitivity, we examined mice that have been refed for 6 h after a 24-h fast. Refeeding wild-type mice resulted in decreased serum adiponectin and increased leptin. In transgenic mice, however, the regulation of these hormones by refeeding was lost for adiponectin and diminished for leptin. Refed transgenic female and male mice no longer exhibited decreased serum adiponectin in the refed state, and they were no longer insulin resistant as by lower or unchanged insulin and glucose levels. We conclude that increased hexosamine levels in fat, mimicking excess nutrient delivery, are sufficient to cause insulin resistance in skeletal muscle. Changes in serum adiponectin correlate with the insulin resistance of the transgenic animals.
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Affiliation(s)
- Mark Hazel
- Department of Medicine, University of Utah, Salt Lake City, Utah 84132, USA
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Kazumi T, Kawaguchi A, Hirano T, Yoshino G. Serum adiponectin is associated with high-density lipoprotein cholesterol, triglycerides, and low-density lipoprotein particle size in young healthy men. Metabolism 2004; 53:589-93. [PMID: 15131762 DOI: 10.1016/j.metabol.2003.12.008] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The chromosomal localization of adiponectin has been found to be mapped to human chromosome 1q21.4-1q23, a region that was identified as a susceptibility locus for familial combined hyperlipidemia and polygenic type 2 diabetes. As these 2 disorders are associated with low high-density lipoprotein (HDL)-cholesterol, high triglycerides, and insulin resistance (IR), we examined the relation of serum adiponectin concentrations to serum lipid and lipoprotein profiles as well as IR in young healthy men. Serum adiponectin levels were positively associated with HDL-cholesterol, apolipoprotein (apo) A1, and low-density lipoprotein (LDL) particle size, and negatively associated with triglycerides and apo B. Negative associations were also found between adiponectin and body mass index (BMI), percent body fat, and IR,as determined by homeostasis model assessment (HOMA). However, after adjustment for BMI, no significant associations were found between adiponectin and LDL particle size and apo B. In a multiple regression analysis including all variables that showed significant univariate associations with adiponectin, associations of adiponectin with HDL-cholesterol (beta = 0.079, P =.0009), percent body fat (beta = -0.165, P =.002), and serum leptin (beta = -0.291, P =.01) were statistically significant. HDL-cholesterol (beta = 0.077, P =.001), percent body fat (beta = -0.078, P =.03), and LDL size (beta = 0.092, P =.03) emerged as significant and independent determinants of adiponectin after HOMA IR, fasting glucose, triglycerides, and systolic blood pressure (BP) were taken into account. Together, these variables explained 19% of adiponectin variability in the 2 models. HOMA IR did not emerge as a determinant of adiponectin in both models. These findings suggest that in young healthy men hypoadiponectinemia is more closely related to adiposity and dyslipidemia than IR.
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Affiliation(s)
- Tsutomu Kazumi
- Department of Food Sciences and Nutrition, Mukogawa Women's University, Hyogo, Japan
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Tomimoto S, Hashimoto H, Shintani N, Yamamoto K, Kawabata Y, Hamagami KI, Yamagata K, Miyagawa JI, Baba A. Overexpression of pituitary adenylate cyclase-activating polypeptide in islets inhibits hyperinsulinemia and islet hyperplasia in agouti yellow mice. J Pharmacol Exp Ther 2004; 309:796-803. [PMID: 14742740 DOI: 10.1124/jpet.103.062919] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Pituitary adenylate cyclase-activating polypeptide (PACAP) is an intraislet neuropeptide and shares insulinotropic and insulin-sensitizing properties with glucagon-like peptide-1 (GLP-1); however, the pathophysiological significance of PACAP in diabetes remains largely unknown. To assess this, we crossed our recently developed transgenic mice overexpressing PACAP in pancreatic beta-cells (Tg/+), with lethal yellow agouti (KKA(y)) mice (A(y)/+), a genetic model for obesity-diabetes, and examined the metabolic and morphological phenotypes of F(1) animals. Tg/+ mice with the A(y) allele (Tg/+:A(y)/+) developed maturity-onset obesity and diabetes associated with hyperglycemia, hyperlipidemia, and hyperphagia, similar to those of A(y)/+ mice, but hyperinsulinemia was significantly ameliorated in Tg/+:A(y)/+ mice. Although A(y)/+ mice exhibited a marked increase in islet mass resulting from hyperplasia and hypertrophy, this increase was significantly attenuated in Tg/+:A(y)/+ mice. Size frequency distribution analysis revealed that the very large islets comprising one-fourth of islets of A(y)/+ mice were selectively reduced in Tg/+:A(y)/+ mice. Because functional defects have been demonstrated in the large islets of obese animal models, together these findings suggest that PACAP regulates hyperinsulinemia and the abnormal increase in islet mass that occurs during the diabetic process.
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Affiliation(s)
- Shuhei Tomimoto
- Laboratory of Molecular Neuropharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Japan
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Akahoshi A, Koba K, Ohkura-Kaku S, Kaneda N, Goto C, Sano H, Iwata T, Yamauchi Y, Tsutsumi K, Sugano M. Metabolic effects of dietary conjugated linoleic acid (CLA) isomers in rats. Nutr Res 2003. [DOI: 10.1016/j.nutres.2003.08.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Miyanaga F, Ogawa Y, Ebihara K, Hidaka S, Tanaka T, Hayashi S, Masuzaki H, Nakao K. Leptin as an adjunct of insulin therapy in insulin-deficient diabetes. Diabetologia 2003; 46:1329-37. [PMID: 12928770 DOI: 10.1007/s00125-003-1193-6] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2003] [Revised: 06/30/2003] [Indexed: 12/19/2022]
Abstract
AIMS/HYPOTHESIS The purpose of this study was to assess the therapeutic implication of leptin in insulin-deficient diabetes. METHODS Insulin-deficient diabetes was induced by streptozotocin (STZ) in transgenic skinny mice overexpressing leptin. Plasma concentrations of glucose, insulin, and leptin were measured. The effects on body weight, food intake, and hypothalamic gene expressions were analyzed. After diabetes was induced, graded doses of insulin ranging from 0.4 to 51.2 mU.g(-1).day(-1) were injected. Co-administration of leptin and insulin was also carried out using osmotic pumps. RESULTS After STZ injection, both transgenic and non-transgenic littermates developed marked hyperglycaemia as a result of severe hypoinsulinaemia [termed diabetic transgenic skinny mice overexpressing leptin (diabetic TGM) and diabetic non-transgenic littermates (diabetic WT) respectively], although diabetic TGM were more sensitive to exogenously administered insulin than diabetic WT. Diabetic WT were hypoleptinaemic and hyperphagic relative to non-diabetic WT, whereas diabetic TGM, which remained hyperleptinaemic, were less hyperphagic than diabetic WT. After STZ injection, hypothalamic expressions of orexigenic and anorexigenic peptide mRNAs were up-regulated and down-regulated, respectively, in diabetic WT, whereas they were unchanged in diabetic TGM. Diabetic TGM became normoglycaemic, when treated with insulin at such doses that did not improve hyperglycaemia in diabetic WT. We found that a sub-threshold dose of insulin that does not affect glucose homeostasis is effective in improving the diabetes in normal mice rendered diabetic by STZ injection, when combined with leptin. CONCLUSIONS/INTERPRETATION This study suggests that leptin could be used as an adjunct of insulin therapy in insulin-deficient diabetes, thereby providing an insight into the therapeutic implication of leptin as an anti-diabetic agent.
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Affiliation(s)
- F Miyanaga
- Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, Kyoto, Japan
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Holdstock C, Engström BE, Ohrvall M, Lind L, Sundbom M, Karlsson FA. Ghrelin and adipose tissue regulatory peptides: effect of gastric bypass surgery in obese humans. J Clin Endocrinol Metab 2003; 88:3177-83. [PMID: 12843162 DOI: 10.1210/jc.2002-021734] [Citation(s) in RCA: 236] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Presently surgery is the most effective way to obtain a controlled weight reduction in morbidly obese patients. Roux-en-Y gastric bypass (RYGBP) surgery is effective and used worldwide, but the exact mechanism of action is unknown. The effect of RYGBP on ghrelin, insulin, adiponectin, and leptin levels was investigated in 66 obese subjects; mean weight 127 kg (range, 96-195 kg) and mean body mass index (BMI) 45 kg/m(2) (range, 33-64) before and after surgery. Ghrelin levels were also compared in 10 nonoperated and 10 operated obese, BMI-matched women. RYGBP resulted in 22% and 30% weight loss at 6 and 12 months, respectively. Ghrelin increased by 44% and 62% and adiponectin by 36% and 98%, but insulin declined by 57% and 62% and leptin by 60% and 64%. The changes were all related to the reduction in BMI. In addition, ghrelin and insulin were inversely correlated at all time points as were changes of the peptides at 12 months (F = 4.9, P = 0.031), independent of the change in BMI. No evidence for RYGBP surgery per se having an effect on ghrelin levels, independent of weight loss, was obtained. The profound changes in the regulatory peptides are likely to reflect the new state of energy balance achieved. A close inverse association between ghrelin and insulin was observed, supporting an important role for ghrelin in glucose homeostasis.
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Affiliation(s)
- Camilla Holdstock
- Department of Medical Sciences/Internal Medicine, Uppsala University Hospital, S-751 85 Uppsala, Sweden
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Nakagawa T, Ogawa Y, Ebihara K, Yamanaka M, Tsuchida A, Taiji M, Noguchi H, Nakao K. Anti-obesity and anti-diabetic effects of brain-derived neurotrophic factor in rodent models of leptin resistance. Int J Obes (Lond) 2003; 27:557-65. [PMID: 12704399 DOI: 10.1038/sj.ijo.0802265] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE Obesity in rodents and humans is mostly associated with elevated plasma leptin concentrations, suggesting a new pathological concept of 'leptin resistance'. We have demonstrated that brain-derived neurotrophic factor (BDNF) can improve obesity and diabetes of C57BL/KsJ db/db (db/db) mice. In this study, we investigated whether or not BDNF is effective in two different models of leptin resistance, an acquired model and a genetic model. DESIGN C57BL/6J mice rendered obese by consumption of a high-fat diet (diet-induced obesity (DIO) mice) were used as an acquired model and lethal yellow agouti mice (KKA(y) mice) as a genetic model of leptin resistance. Food intake and glucose metabolism were studied after acute or repetitive administration of BDNF. RESULTS Intraperitoneal administration of BDNF (10 mg/kg, twice/day) significantly reduced cumulative food intake of DIO and KKA(y) mice, whereas they were unresponsive to leptin administration. Repetitive subcutaneous administration of BDNF (10 mg/kg daily for 6 days) reduced food intake and improved impaired glucose tolerance in DIO mice. Pair feeding of vehicle-treated DIO mice with the same amount of chow consumed by the BDNF-treated group did not improve the impaired glucose homeostasis, indicating that the antidiabetic effect is not due to decreased food intake. We also observed that BDNF is effective in improving obesity and diabetes of KKA(y) mice. CONCLUSION This study demonstrated antiobesity and antidiabetic effects of BDNF in two different models of leptin resistance, thereby suggesting the therapeutic potential of BDNF in the treatment of leptin-resistant obesity and diabetes.
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Affiliation(s)
- T Nakagawa
- Discovery Research Laboatories I, Sumitomo Pharmaceuticals Research Division, Osaka, Japan
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