Fetal Sex Modulates Hofbauer Cells' Response to Diabetes in Human Placenta.

Background

Hofbauer cells (HBCs) are fetal-origin macrophages in the placental villous stroma that contribute to immune tolerance at the feto-maternal interface. They predominantly display an M2 phenotype, characterized by CD206 expression.

Methods

Using immunohistochemistry and morphometric analysis, we quantified HBCs, assessed CD206 intensity and morphology, and evaluated apoptotic body accumulation in placental villi. Comparisons were made among pregnancies complicated by type 1 diabetes mellitus (T1DM), gestational diabetes mellitus (GDM), and normoglycemic controls, as well as between male and female fetuses.

Results

Significant effects of maternal diabetes and fetal sex on CD206 intensity were observed ([diagnosis: F = 2773.00, p < 0.0001; sex: F = 12.19, p = 0.0005]), with a strong interaction (F = 165.40, p < 0.0001). In controls, CD206 intensity was higher in female than male fetuses (p < 0.0001). Across groups, CD206 intensity decreased progressively from controls to GDM and T1DM, with a more pronounced reduction in females. Reduced CD206 was associated with elongation and irregular HBC morphology and increased IL-1β (r = -0.392, p = 0.003; r = -0.609, p < 0.0001) suggesting less tolerogenic phenotype. For apoptotic bodies, significant main effects of maternal diabetes and fetal sex were detected ([diagnosis: F = 97.16, p < 0.0001; sex: F = 15.88, p = 0.0001]). Accumulation increased progressively from controls to GDM and T1DM, with higher counts in males.

Conclusions

Maternal diabetes is associated with reduced CD206 intensity, altered HBC morphology, and accumulation of apoptotic bodies in placental villi. Our results suggest greater HBC plasticity, potentially contributing to a tolerogenic placental environment in females.