Remodelling of collagen fibres in the placentas of women with venous insufficiency during pregnancy

Haemodynamic changes produced during pregnancy lead to elevated venous pressure in the legs and an increased resting consumption of oxygen. These events can cause varicose veins, or venous insufficiency (VI), which by creating an environment of hypoxia could affect the structure and function of the placental barrier. This study assesses the remodelling state of the placental villi by examining differences in collagens with a known role in villus structure and in placental barrier permeability between patients with and without VI. Samples of 67 placentas from women with VI (n=24) and without VI (n=43) during their pregnancy were processed for gene and protein expression analysis of COL-I, COL-III, MMP-2 and MMP-9 by RT-qPCR and immunohistochemistry. While no differences in COL-I expression levels were detected in the samples from women with and without VI, significant differences did emerge in both gene and protein expression levels of COL-III. Importantly, COL-I/III ratios were reduced in the VI group compared to controls. MMP-2 activity was similar in the two groups while MMP-9 levels were significantly elevated in VI with greatest expression differences observed at the level of the decidual cells. Mothers who developed VI during pregnancy showed significantly higher COL-III and MMP-9 levels consistent with a state of remodelling of the placental villi.