TGFB1 and obstructive sleep apnea syndrome: We identified high plasma PSPC1 protein levels in the patients with OSA compared with HV (p = 0.017) (Figure 1c) and observed a similar pattern with TGFβ, SMAD3, and SMAD4 (p = 0.0193, p = 0.0008 and p < 0.0001, respectively) (Figure S1b).