Increased prolidase activity in Alzheimer’s dementia: A case-control study

•The activity of prolidase enzyme in the plasma of Alzheimer’s disease (AD) subjects and healthy controls was measured.•The mean prolidase activity levels were significantly higher in AD subjects than that of the control group.•The increase was found to be significant beginning at mild AD with an inverse correlation with HMSE scores. Prolidase enzyme, which catalyzes the final step in collagen metabolism can influence the cognitive functions through changes in extracellular matrix (ECM) resulting in altered synaptic connectivity in Alzheimer’s disease (AD). In this study, it was found that the prolidase activity was significantly higher (p = 0.0016) in AD subjects (5.62 ± 2.05 U/ mL) than control group (4.45 ± 0.92 U/ mL). The increase was significant beginning at mild AD (p = 0.006) with an inverse correlation with HMSE scores (p = 0.0344), thus implying that prolidase mediated alterations in ECM may be associated with the cognitive deficits seen in AD.