The Association between Vascular Endothelial Growth Factor-related Factors with Severity of Multiple Sclerosis

Previous studies have demonstrated that vascular endothelial growth factor (VEGF) can trigger angiogenesis as well as inflammation through binding to its membranous receptor-1 on endothelial and inflammatory cells. We aimed to correlate the circulatory number of cells expressing such receptor as well as the serum level of VEGF and the soluble form of its receptor-1 (sVEGFR1) to the severity of multiple sclerosis (MS). This case-control study was done on 102 cases of MS lacking any other inflammatory or pathologic conditions and 75 healthy volunteer subjects. The severity of MS was examined by expanded disability status scale (EDSS). The serum levels of VEGF and sVEGFR1 were measured by ELISA, and the circulatory frequency of VEGFR1 expressing cells was counted by flowcytometry. Then, the correlation of these variables was evaluated by pearson’s correlation coefficient and spearman’s test. We also investigated the influence of sex, age, treatment duration, and the number of recurrences on such association through linear multivariate regression method. We found an increase in circulatory level of VEGFR1 expressing cells and the serum level of VEGF as well as sVEGFR1 in MS patients compared to healthy controls (p<0.001). The greater severity of MS, the higher VEGFR1 expressing cells (ρ=0.47; p<0.001), serum level of VEGF (ρ=0.44; p<0.001), and sVEGFR1 (ρ=0.76; p<0.001). Having adjusted the effects of VEGF on sVEGFR1, we found a significant association between the EDSS score and sVEGFR1 (β=0.007; p<0.001). Our findings revealed that circulatory membranous as well as soluble expression of VEGFR1 increases during angiogenic and inflammatory phenomena of MS. Such increase may exacerbate the symptoms and cause more disability.