The Effect of a Sustained High-Fat Diet on the Metabolism of White and Brown Adipose Tissue and Its Impact on Insulin Resistance: A Selected Time Point Cross-Sectional Study |
| |
Authors: | Babu Raja Maharjan Susan V. McLennan Christine Yee Stephen M. Twigg Paul F. Williams |
| |
Affiliation: | 1.Greg Brown Diabetes & Endocrinology Laboratory, Sydney Medical School, University of Sydney, Sydney, NSW 2006, Australia; (S.V.M.); (C.Y.); (S.M.T.);2.Department of Biochemistry, School of Medicine, Patan Academy of Health Sciences, Lalitpur 44700, Nepal;3.New South Wales Health Pathology, Sydney, NSW 2050, Australia;4.Department of Endocrinology, Royal Prince Alfred Hospital, Sydney, NSW 2006, Australia |
| |
Abstract: | (1) Background: studies on the long-term dynamic changes in fat depot metabolism in response to a high-fat diet (HFD) on hepatic lipid deposition and insulin resistance are sparse. This study investigated the dynamic changes produced by HFD and the production of dysfunctional fat depots on insulin resistance and liver lipid metabolism. (2) Methods: mice fed a chow or HFD (45% kcal fat) diet had three fat depots, liver, and blood collected at 6, 10, 20, and 30 weeks. Anthropometric changes and gene markers for adipogenesis, thermogenesis, ECM remodeling, inflammation, and tissue insulin resistance were measured. (3) Results: early responses to the HFD were increased body weight, minor deposition of lipid in liver, increased adipocyte size, and adipogenesis. Later changes were dysfunctional adipose depots, increased liver fat, insulin resistance (shown by changes in ITT) accompanied by increased inflammatory markers, increased fibrosis (fibrosis > 2-fold, p < 0.05 from week 6), and the presence of crown cells in white fat depots. Later, changes did not increase thermogenic markers in response to the increased calories and decreased UCP1 and PRDM16 proteins in WAT. (4) Conclusions: HFD feeding initially increased adipocyte diameter and number, but later changes caused adipose depots to become dysfunctional, restricting adipose tissue expansion, changing the brown/beige ratios in adipose depots, and causing ectopic lipid deposition and insulin resistance. |
| |
Keywords: | long high-fat diet fat cell dysfunctionality ectopic lipid deposition insulin resistance |
|
|