title: Vitamin D Insufficiency Exacerbates Adipose Tissue Macrophage Infiltration and Decreases AMPK/SIRT1 Activity in Obese Rats.
abstract: Obesity is recognized as a state of chronic low-grade systemic inflammation due to adipose tissue macrophage infiltration and production of proinflammatory adipokines. Decreased vitamin D status is associated with obesity. The specific aim of the present study is to investigate the effects of vitamin D on obesity-induced adipose tissue inflammation. Male Sprague-Dawley rats were randomized and fed a normal diet (NOR, 1000 IU vitamin D/kg diet), a 45% high-fat diet (HF, 1000 IU vitamin D/kg diet), or a 45% high-fat diet containing 25 IU vitamin D/kg diet (HF+LVD) for 12 weeks. The vitamin D-insufficient diet (HF+LVD) led to vitamin D inadequacy as determined by serum 25(OH)D level, 68.56 ± 7.97 nmol/L. The HF+LVD group exacerbated HF-increased adipocyte size, adipogenic gene expression of PPARγ, adipose tissue macrophage recruitment, and proinflammatory cytokine IL-6 and TNFα levels in epididymal white adipose tissue. In addition, vitamin D insufficiency significantly decreased mRNA levels of β-oxidation-related genes such as CPT1α, PGC1α, PPARα, VLCAD, LCAD, MCAD, and UCP1. Moreover, significant decrements of SIRT1 and AMPK activity were noted in obese rats fed with a vitamin D-insufficient diet. The observed deleterious effects of vitamin D insufficiency on adipose tissue expansion, immune cell infiltration and inflammatory status suggest vitamin D plays a beneficial role in adipocyte metabolic metabolism and obesity progression. SIRT1 and AMPK activity may play a role in the mechanism of vitamin D action.
authors.affiliation: Department of Nutritional Science and Food Management, Ewha Womans University, Seoul 03760, Korea. eugenics77@hotmail.com.
authors.forename: Eugene
authors.initials: E
authors.lastname: Chang
authors.affiliation: Department of Nutritional Science and Food Management, Ewha Womans University, Seoul 03760, Korea. yhmoon@ewha.ac.kr.
authors.forename: Yangha
authors.initials: Y
authors.lastname: Kim
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000378:metabolism*; D017667:Adipocytes / Q000378:metabolism; D050156:Adipogenesis; D000273:Adipose Tissue / Q000166:cytology / Q000378:metabolism*; D052436:Adipose Tissue, White / Q000378:metabolism; D000818:Animals; D016207:Cytokines / Q000097:blood; D059305:Diet, High-Fat; D007249:Inflammation / Q000209:etiology; D050356:Lipid Metabolism / Q000235:genetics; D008264:Macrophages / Q000378:metabolism*; D008297:Male; D009765:Obesity / Q000150:complications* / Q000378:metabolism; D047495:PPAR gamma / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D017207:Rats, Sprague-Dawley; D056564:Sirtuin 1 / Q000378:metabolism*; D014807:Vitamin D / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000097:blood*; D014808:Vitamin D Deficiency / Q000097:blood / Q000150:complications* / Q000378:metabolism; D014815:Vitamins / Q000008:administration & dosage / Q000097:blood
chemical_list: D016207:Cytokines; D047495:PPAR gamma; D012333:RNA, Messenger; D014815:Vitamins; D014807:Vitamin D; C104450:25-hydroxyvitamin D; D055372:AMP-Activated Protein Kinases; C488368:Sirt1 protein, rat; D056564:Sirtuin 1
keywords: adenosine monophosphate-activated protein kinase (AMPK); adipose tissue macrophage infiltration; obesity; sirtulin 1 (SIRT1); vitamin D