Peripheral fat loss and decline in adipogenesis in older humans

Abstract

Objective: Aging is associated with a redistribution of body fat including a relative loss of subcutaneous peripheral fat. These changes in body fat can have important clinical consequences since they are linked to increased risk of metabolic complications. The causes and mechanisms of loss of peripheral fat associated with aging are not clear. The aim of this study was to assess whether defects in adipogenesis contribute to fat loss in aging humans, as suggested from animal studies, and to evaluate the role of inflammation on pathogenesis of fat loss.

Materials/methods: Preadipocytes isolated from subcutaneous peripheral fat of healthy young and elderly subjects were compared in their ability to replicate and differentiate.

Results: The results show that both the rate of replication and differentiation of preadipocytes are reduced in older subjects. The reduction in adipogenesis is accompanied by a higher plasma level of the inflammatory marker, soluble tumor necrosis factor receptor 2, and greater release of tumor necrosis factor α from fat tissue.

Conclusions: Thus, the gradual relative loss of peripheral fat in aging humans may in part result from a defect in adipogenesis, which may be linked to inflammation and increased release of proinflammatory cytokines from fat tissue.

Conflict of interest statement

CONFLICT OF INTEREST

None of authors has any conflict of interest

Copyright © 2013 Elsevier Inc. All rights reserved.

Figures

Figure 1. Proliferation of preadipocytes isolated from subcutaneous fat of Young and Elderly subjects

Cell number was assessed with the MTT assay at 48, 72, 96, 120, 144 and 168 h (Mean ± SEM). The slope of the growth curve was significantly lower in Elderly Subjects (P

Figure 2. Relationship between subcutaneous preadipocyte differentiation and ratio of limb to trunk fat (kg/kg)

Differentiation was assessed with Oil Red O staining of intracellular lipid. A comparable relationship was obtained when differentiation was assessed by direct count of the proportion of differentiated cells (R = 0.48, P = 0.02). ○ young; □ elderly

Figure 3. (Supplemental online appendix). Differentiation of preadipocytes isolated from subcutaneous fat of Young and Elderly subjects

Preadipocytes were differentiated for 12 d and then intracellular lipid were stained with Oil Red O. a. Pictures (40X) of stained adipocytes from young and elderly subjects showing intracellular lipid accumulation in red. b. Spectrophotometric quantification of Oil Red O extracted from differentiated preadipocytes in the 2 groups. Mean ± SEM. * P