Metformin reverses mitophagy dysfunctions in peripheral blood mononuclear cells (PBMCs) isolated from type 2 diabetes mellitus patients, originally showing decreased expression of phosphatase and tensin homolog (PTEN)-induced kinase 1 (PINK1) and parkin [34] and promotes a neuroprotective effect in hyperglycaemia associated with cerebral ischaemia/reperfusion injury modulating mitophagy and apoptosis [35]. Here, PINK1 is linked to type 2 diabetes mellitus.