Obesity itself, probably primarily when associated with hypertrophic expansion, is associated with increased markers of cellular senescence, including adipose tissue β-galactosidase activity, a marker of high lysosomal activity and lysosomal content, as well as increased plasminogen activator inhibitor 1 (PAI-1), p53 and cyclin D kinase inhibitors, including p16Ink4a [30]. Here, SERPINE1 is linked to obesity due to melanocortin 4 receptor deficiency.