Histological changes in placental syncytiotrophoblasts of poorly controlled gestational diabetic patients.

It seems reasonable to expect that biochemical changes occurring in the pregnant woman with diabetes should be reflected in the placenta structure. However, it has not been possible to correlate placental morphology with glycemic control in a comparison between those with long life diabetes and poorly controlled gestational diabetes. In the present study we have histologically studied the syncytiotrophoblast of human placentae from overt diabetic and poorly controlled gestational diabetic patients. Using specific staining techniques and direct light microscopy we qualitatively studied these placentae and compared them with the normal placentae. We found fibrin thrombi, villous oedema, hyperplasia and thickening of basement membrane in the placentae of poorly controlled gestational diabetic mothers. Direct microscopy revealed that these various changes in syncytiotrophoblast structure were marked in the poorly controlled gestational placenta compared with overt diabetics, and could have been due to the presence of histochemical compounds e.g. general carbohydrates and lipids. These studies may indicate that poor control of diabetes during the gestation as indicated by high level HbAlc may result in the accummulation of carbohydrate compounds and fat droplets in the placental basement membrane, leading to structural changes in the placental cells.

Features of insulin receptor interaction in placenta from normal, overt and poorly controlled gestational diabetic patients.

Features of insulin binding to trophoblast plasma membranes were studied in six normal pregnant women (NP), six overt diabetes (ODP) and six poorly controlled glycemic gestational patients (PCDP) i.e. women who did not strictly follow the management of diabetes mellitus during pregnancy. A decreased maximum specific insulin receptor binding per 0.1 mg membrane protein in placenta from PCDP (12%) was found comparing with that from ODP or NP (17.5% and 36.2%, respectively, P < 0.01), The insulin binding in PCDP declined at a faster rate until it reached minimum when studied at a higher temperature (25-37 degrees C). The binding equilibrium was likewise attained faster at this temperature than that at lower temperature of 4 degrees C for all studied groups. The insulin receptor binding in all studied groups was pH dependent. The maximum binding in ODP and PCDP groups was attained at pH 7.8 while for NP maximum binding was at pH 7.4. The competitive binding assay was carried out with 14 concentrations of unlabelled insulin and the half maximal displacement of 125I-insulin was at 8 x 10(-9) M, 6 x 10(-9) M and 4 x 10(-9) M for NP, ODP and PCDP, respectively (P < 0.05) suggesting the differences in the effect of glycemic control on the insulin binding. Furthermore the binding yielded curvilinear Scatchard plots with the apparent affinity of the receptors being affected in the ODP and PCDP groups.(ABSTRACT TRUNCATED AT 250 WORDS)