Preterm birth increases susceptibility to hyperglycemia induced glomerular alterations in male mice.

Diabetic kidney disease (DKD) is the leading cause of progressive chronic kidney disease in adults in the United States. However, the impact of preterm birth on the progression of DKD has not been studied. The goal of this project was to determine the effect of preterm birth on kidney health after exposure to hyperglycemia. CD-1 pups born preterm (19 days post conception (dpc)) and term (20 dpc) were studied, and outcomes of the male mice were reported. Preterm and term mice were treated with streptozotocin at six weeks to induce hyperglycemia. Body weight and blood sugar were monitored. Histologic, molecular, and imaging techniques were used to characterize the mice at 18 weeks. The preterm mice with diabetes had a lower podocyte density, lower proximal tubular fraction, and more atubular glomeruli compared to the term mice without diabetes. The preterm mice with diabetes also had a lower podocyte density and lower renin expression compared to term mice with diabetes. Based on single-cell RNA sequencing, the preterm mice with diabetes had increased expression of genes related to the angiogenesis migration pathway-related in endothelial cells and increased expression of genes in the actin adhesion pathway in podocytes compared to term mice with diabetes. Furthermore, the preterm mice with diabetes exhibited a weaker endothelial cell-podocyte interaction compared to term mice with diabetes. These data suggest that preterm birth increases susceptibility to glomerular and tubular damage after a brief "second hit" of hyperglycemia. In conclusion, preterm birth disrupts endothelial-podocyte crosstalk and increases susceptibility to kidney injury induced by hyperglycemia.