The increase in CHOP levels could also be ascribed to the mitochondrial UPR (UPRMT); however, our results showing higher levels of BiP and PDIA6 reflect the activation of ER stress in obesity, in agreement with previous reports, while the contribution of UPRMT to cardiovascular alterations in obesity is currently uncertain. This evidence concerns the gene HSPA5 and obesity due to melanocortin 4 receptor deficiency.