TPO and multiple system atrophy: Moreover, we have evaluated the levels of nitrites and nitrates (generally referred to as NO) in culture supernatants and found a significant increase of NO release in cells exposed to both RQ-MSA and RQ-PD compared to unseeded αSyn_RT-QuIC reaction mix (RQ-MSA vs. RQ-no seed: p < 0.0001; RQ-MSA vs. RQ-PD: p < 0.001; RQ-PD vs. RQ-no seed: p = 0.004) (Figure 3G).