Relationship between Parkinson's disease and diabetes mellitus: Evidence from the bench to bedside

Parkinson's disease (PD) is a neurodegenerative disease common in older people and clinically manifests as resting tremors, bradykinesia, muscle stiffness, and impaired postural balance. Diabetes mellitus (DM) is a metabolic disease characterized by high blood sugar levels, independent of insulin alterations. With the aging global population, comorbidities of PD and DM have become a major burden on healthcare systems; however, the underlying links between the two diseases remain incompletely understood. Previous work has suggested that PD and DM have several potentially overlapping mechanisms of action. This systematic review addresses a critical need for integrating clinical and preclinical evidence to identify novel therapeutic strategies for co-managing PD and DM. Here, we summarize the findings from recent publications, focusing on the pathogenesis of PD and DM, insulin resistance, treatment of PD by antidiabetic drugs, or on the contrary, treatment of DM by common PD therapeutics.