The Influence of Insulin Resistance and Fat Reallocation on Bone Marrow Adipose Tissue and Bone Mineral Density

Program: Abstracts - Orals, Poster Previews, and Posters
Session: SAT 224-243-Osteoporosis
Clinical
Saturday, March 7, 2015: 1:00 PM-3:00 PM
Hall D-F, Bone & Calciotropic Hormones (San Diego Convention Center)

Poster Board SAT-243
Francisco J A de Paula1, Adriana Lelis Carvalho2, Iana Mizumukai de Araujo3, Carlos Ernesto Garrido Salmon3, Jorge Elias Jr.4 and Marcello Henrique Nogueira-Barbosa3
1School of Medicine of Ribeirao Preto, Ribeirao Preto, Brazil, 2Medical School of Ribeirão Preto, USP, Ribeirão Preto, Brazil, 3Medical School of Ribeirão Preto, USP, Ribeirao Preto, Brazil, 4Ribeirao Preto Medical School, Ribeirão Preto, Brazil
Introduction: In obesity, the outflow of fat to muscle and liver has been associated with insulin resistance and local impairment of function. However, the relationship between subcutaneous and visceral adipose tissue with bone marrow fat still is to be elucidated. Noteworthy, increased BMAT has been described in patients with anorexia nervosa while there are conflicting results in obese individuals. In this context, BMAT and body fat mass have a controversial relationship. Objectives: Our aim is to evaluate lipid outflow effect on BMAT and bone mineral density (BMD) in normal weight, overweight and obese subjects. Material and Methods: Seventy non-diabetic subjects between 19 to 70 years old were enrolled in the present study (age: 50±14 years; weight: 72±15 kg; height: 1.66±0.09 m; BMI: 26±5 kg/m²). Blood sample was collected to measure glucose, triglycerides, cholesterol, HDL, HbA1c and 25-OHD. BMD and lean mass were measured by DXA. BMAT, visceral and liver fat were assessed in 52 individuals by MRI (1,5 Tesla). Results: The biochemical assessment shows: HbA1c: 5.5±0.4% (all individuals in normal range); Cholesterol: 201±34 mg/d; Triglycerides: 123±80 mg/dL; 25(OH)D: 25±9 ng/mL. The T-score values were normal in 41%, whereas 46% and 13% exhibited osteopenia and osteoporosis, respectively. Most individuals showed high percentage of body fat (77%), however only 11% had increased fat within liver. The mean values of % body fat, lean mass and liver fat rate were, respectively, 36±7%, 43±10 kg and 3.9±5.5 %. Visceral fat correlated positively with age (r=0.50; p<0.0001), liver fat (r=0.55; p<0.0001) as well as with BMAT (r=0.43; p<0.005). It was observed a trend of correlation between the rate of fat within the liver and BMAT (r= 0.25; p=0.06). Correlation between visceral fat and BMD was not found in this group. Yet, BMAT rate was positively correlated with age (r=0.57; p<0.0001), HbA1c (r=0.34; p<0.05), cholesterol (r=0.35; p<0.05), triglycerides (r=0.38;p<0.005), visceral fat, but no correlation was observed with lumbar spine BMD. The serum levels of insulin and the values of HOMA-IR were positively correlated with visceral (Insulin: r=0.42; p<0.005, HOMA-IR: r=0.46; p<0.001)) and hepatic fat (insulin: r=0.43; p<0.005; HOMA-IR: r=0.44; p<0.005). On the other hand, it was observed no association between circulatory insulin (r=0.01; p=0.9) and HOMA-IR (r=0.09; p=0.6) with BMAT. Conclusion: The present results call attention to the complex relationship between the BMAT with metabolic disturbances classically associated with insulin resistance. BMAT was correlated with circulatory levels of glucose, lipids, HbA1c and visceral fat. Curiously, it was not verified association between BMAT neither with the amount of fat in liver nor with insulin and HOMA-IR.  Further studies are necessary to elucidate the effect of insulin resistance and fat overflow on BMAT and BMD.

Nothing to Disclose: FJAD, ALC, IMD, CEGS, JE Jr., MHN

*Please take note of The Endocrine Society's News Embargo Policy at https://www.endocrine.org/news-room/endo-annual-meeting

Sources of Research Support: FAPESP Grant 2012/14603-6 and CNPq 306027/2011-9
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