The role of phospholipase A2 in multiple Sclerosis: A systematic review and meta-analysis.

Phospholipases A2 (PLA) are a diverse group of enzymes that cleave the fatty acids of membrane phospholipids. They play critical roles in pathogenesis of neurodegenerative diseases such as multiple sclerosis by enhancing oxidative stress and initiating inflammation. The levels of PLA activity in MS patients compared to controls and role of inhibiting PLA activity on severity scores in different experimental models are not comprehensively assessed in the light of varying evidence from published studies. The objective of this systematic review is to determine the association between PLA activity and multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE). We performed a systematic review of six studies that assessed PLA activity in MS patients compared to controls and nine studies that assessed PLA activity in EAE. sPLA nor Lp-PLA activity were not increased in MS compared to controls in five of those six studies. A difference in sPLA activity was only found in a study that measured the enzyme activity in urine. However, inhibiting cPLA or sPLA led to lower clinical severity or no signs of EAE in mice, and a lower incidence of EAE lesions compared to animals without cPLA inhibition. These findings indicate that PLA appears to play a role in the pathogenesis of EAE.