Effects of obesity and weight loss on the expression of proteins involved in fatty acid metabolism in human adipose tissue.
OBJECTIVE
Disturbances in adipocyte lipolysis in obesity may contribute to elevated circulating non-esterified fatty acid (NEFA) concentrations and insulin resistance. In experimental models, NEFA metabolism is influenced by adipocyte proteins such as adipocyte and keratinocyte lipid binding proteins (aP2/ALBP and mal1/KLBP) and fatty acid translocase (CD36). We investigated the effect of obesity and weight loss on the expression of these proteins in human subcutaneous adipose tissue.


METHODS
Subcutaneous adipose tissue was obtained from 12 obese (body mass index (BMI) 42.4+/-1.6 kg/m(2)) and 12 lean (23.4+/-0.6 kg/m(2)) subjects. The obese subjects underwent gastric banding and biopsies were taken again after 2 y following a significant weight reduction (BMI 32.8+/-1.4 kg/m(2)). Adipose tissue proteins were quantified by Western blotting.


RESULTS
Differential expression of ALBP, KLBP and CD36 was observed in lean and weight-reduced subjects compared with obese individuals. This resulted in a significantly lower ALBP/KLBP ratio in lean and weight-reduced individuals compared to obese subjects. Furthermore there was a significant influence of gender on this ratio. Moreover, the commonly used internal standard protein actin was expressed significantly higher in lean compared to obese individuals.


CONCLUSIONS
The relative content of ALBP and KLBP in human adipose tissue changes with obesity, weight loss and gender indicating differential regulation. Differing responses in the expression patterns of adipose tissue proteins capable of binding NEFAs in response to weight changes suggest a potential importance in the development of obesity-associated complications.
D000199:Actins / Q000378:metabolism; D000273:Adipose Tissue / Q000378:metabolism*; D000328:Adult; D015153:Blotting, Western; D018955:CD36 Antigens; D002352:Carrier Proteins / Q000378:metabolism; D016022:Case-Control Studies; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D005260:Female; D006801:Humans; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism; D009363:Neoplasm Proteins; D009765:Obesity / Q000378:metabolism*; D027361:Organic Anion Transporters / Q000378:metabolism; D025521:Tumor Suppressor Proteins; D015431:Weight Loss
D000199:Actins; D018955:CD36 Antigens; D002352:Carrier Proteins; C107608:FABP7 protein, human; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D008562:Membrane Glycoproteins; D009363:Neoplasm Proteins; D027361:Organic Anion Transporters; D025521:Tumor Suppressor Proteins