Analysis of the collagens from the fetal membranes of diabetic mothers

Abstract

Changes in the basement membranes associated with the placenta and fetal membranes have been observed in diabetic women, but little is known about the underlying alterations at the biochemical level. Present studies are concerned with the amount, chain composition and carbohydrate content of the collagens from amniotic membranes of women with overt and gestational diabetes. Collagens were obtained from these membranes using pepsin digestion and differential salt precipitation. In comparison with controls, the amounts of the interstitial and type IV collagens remained unchanged while the type V samples showed a moderate increase. However, by the use of reduced pepsinization, a fraction containing primarily type VII collagen and some type VI showed a significant increase in the tissues from diabetics, especially those from overt patients. Slab gel electrophoresis of the latter fractions revealed increased amounts of type VII collagen chains. The collagens from diabetics showed only small and marginally significant increases in their carbohydrate content. These observations suggest that changes in the 'intermediate' collagens as a group may play a role in the connective tissue changes associated with diabetes.