MMP2 and amyotrophic lateral sclerosis: This suggests a key role of vascular damage as an early pathogenic ALS mechanism [62,86,87,88,89], data also validated by high levels of metalloproteinase (MMP)-2 and MMP-9 in peripheral blood samples from ALS cases and by the results obtained by Nicaise and colleagues on variations in the composition of vascular NVU elements in the early ALS stage [62].