Abnormalities of adipose cells in massive obesity.

Adipose cells grown in sub-culture are useful to elucidate genetic factors in obesity. Most omental adipose cell strains from 140 massively obese (greater than 170 percent of reference body weight) subjects replicated, in successive sub-cultures, to a significantly higher degree than cells from lean or moderately obese persons. The difference was due to a greater number of rapidly dividing clones. Adipose cells from the massively obese related into the culture medium proteins, native Mr 20,000-65,000, mitogenic on rat preadipocytes. Mitogenic activity of the medium was much less evident with cells from the lean. In the case of several cell strains, culture with 17-beta-estradiol increased the mitogenic activity of the medium. Omental adipose tissue of the massive obese also contained a greater number of adipose cell clones susceptible to differentiation. Hybrids of adipose cells from the massively obese fused with murine renal adenocarcinoma cells (RAG) revealed more prominent differentiation than hybrids comprised of adipose cells from the lean. Further, only those comprised of adipose cells from the obese could recapitulate differentiation in sub-cultures. These findings in culture probably reflect major heritable factors that facilitate the development of massive obesity in humans.