Association between serum levels of methylglyoxal, oligomeric alpha synuclein and DJ-1 with nutritional status, glycemic index and severity of disease in patients with parkinson: a case control study

Abstract

Abstract Background and objective: Parkinson's disease (PD), is the second most common neurodegenerative disease. Although previous studies have suggested protein glycosylation as an important factor in the pathogenesis of PD, less is known about biological factors involved in this interference. The aim of this study was to determine the association between serum levels of methylglyoxal (MGO), oligomeric alpha-synuclein (a-syn), and DJ-1 with nutritional status, glycemic index (GI), and severity of disease in patients with PD. Materials and Methods: In this case-control study (40 PD and 40 healthy control group) an average of dietary GI of four days (24-hour dietary recall questionnaire and three-day food record) was calculated. Body mass index (BMI) and nutritional risk index (NRI) were calculated. The severity of disease was also evaluated by means of the Hoehn and Yahr. Serum levels of MGO, oligomeric α-syn, and DJ-1 were measured by ELISA and compared between the two groups. Correlation of serum factors with GI, nutritional status, and severity of disease was assessed. Results: The mean of GI was significantly higher in PD patients than the control group (p = 0.019). Serum levels of oligomeric a-syn and DJ-1 significantly higher in PD patients than the control group too (p < 0.05). There was no significant difference between serum levels of MGO between the two groups (p > 0.05). In PD patients, BMI (p = 0.001) and NRI score (p = 0.001) was significantly lower than the control group. In patients group, MGO had a positive and significant correlation with oligomeric a-syn (r = 0.603, p < 0.001) and DJ-1 (r = 0.652, p < 0.001). Also, a positive and significant correlation was seen between oligomeric a-syn and DJ-1 (r = 0.727, p < 0.001). There was positive and significant correlation between GI and the serum levels of MGO (r= 0.339, p = 0.015), oligomeric a-syn (r = 0.319, p < 0.045) and DJ-1 (r = 0.454, p < 0.02). BMI was significantly and negetively correlated with oligomeric a-syn levels (r = -0.240, p < 0.031). NRI was also negetively and significantly correlated with serum levels of oligomeric a-syn (r = -0.254, p < 0.029) and DJ-1 (r = -0.331, p = 0.025). Stage of disease was positively and significantly correlated with serum levels of oligomeric a-syn (r = 0.370, p = 0.001), DJ-1 (r = 0.505, p < 0.001), and dietary GI (r = 0.419, p < 0.001) and negatively and significantly correlated with NRI score (r = -0.464, p < 0.001) and BMI (r = -0.411, p < 0.001). Conclusion: The findings of our study support the hypothesis of the elevated levels of oligomeric a-syn and DJ-1 and high levels of GI as well as a higher risk of malnutrition in PD patients. Serum levels of MGO did not differ between the two groups. Keywords: Parkinson’s disease, glycemic index, methylglyoxal, oligomeric alpha-synuclein, DJ-1