SLC9A1 and diabetes mellitus: Under the conditions of diabetes, NHE1 activation stimulates Na+ to enter endothelial cells in order to exchange H+; Na+ accumulates in the cytosol, driving Ca2+ to enter through the Na+-Ca2+ exchanger, and ultimately leads to cytosolic and mitochondrial Ca2+ overload causing endothelial cell damage by impairing mitochondrial function [13].