Increased growth stimulation of fibroblasts from diabetics by diabetic serum factors of low molecular weight.

Serum factors from non-ketotic poorly controlled diabetic patients when compared to serum factors from normal subjects, stimulate growth and protein synthesis of cultured fibroblasts from diabetic patients by 25-50%. This increased growth stimulating effect of diabetic serum is mainly related to low molecular weight components (mol. wt. < 12,000 daltons), but not to insulin or glucose. These low molecular weight components of diabetic serum are effective only in combination with serum factors of a molecular weight > 12,000 daltons which are essential for initiation and continuous stimulation of cellular growth. As the growth stimulation by diabetic serum factors with a molecular weight < 12,000 daltons does not differ from comparable normal serum factors, the relevance of these serum factors (e.g. growth hormone, lipoproteins) for the increased growth stimulation of mesenchymal cells in diabetes mellitus seems to be only of limited importance. In as much as these in vitro results represent the in vivo situation, chronic exposure of vascular cells from diabetics to these serum factors could be related to the increased angiopathic risk in diabetes mellitus.