Decreased type III and V collagen expression in chorionic villi of hydatidiform mole.

To investigate the characteristic structure of hydatidiform mole, various types of collagen expression were determined in human villous tissues obtained from normal pregnancies (n = 17) and complete hydatidiform moles (n = 10). Indirect immunofluorescent staining was performed to detect type I, III, and VI collagen with specific monoclonal antibodies. Collagens were also extracted from the villous tissues obtained from normal pregnancy and hydatidiform mole by the salt precipitation method. Immunohistochemical staining for type I, III, and VI collagen revealed weak staining of the villous stroma in hydatidiform mole compared with that in normal pregnancy. Both the ratios of type III to type I collagen and the ratios of type V to type I collagen in the villous tissues were significantly decreased (P < 0.05) in molar pregnancy compared with those in normal pregnancy. These results suggest that alterations in the distribution and composition of collagen might play an important role in determining the pathophysiology and structure of hydatidiform mole.