Fig 2: Soluble SMAD4 is overexpressed in OSA patients with early subclinical atherosclerosis. (A) Soluble SMAD4 (sSMAD4) levels in plasma from EPIOSA subjects: healthy subjects without early subclinical atherosclerosis (HS-non-eSA, n = 62) or with early subclinical atherosclerosis (HS-eSA, n = 7) and in OSA patients without (OSA-non-eSA, n = 69) and with early subclinical atherosclerosis (OSA-eSA, n = 30) determined by ELISA. Data are presented as median (interquartile range), maximum and minimum values. Comparisons between groups were performed by the Kruskal–Wallis test. (B) Comparison of sSMAD4 plasma levels adjusted by sex, age, body mass index and mean blood pressure between the study groups. The rectangles correspond to the adjusted means and the error bars to the standard error of the means. Comparisons were performed by Welch and Brown-Forsythe analysis of variance test. (C,D) Correlation between sSMAD4 plasma concentration and (C) apnea–hypopnea index [AHI] (n = 168) and (D) oxygen desaturation index [ODI] (n = 168). Spearman’s correlation coefficients (?) and p-values are shown. *: p < 0.05, **: p < 0.01, ****: p < 0.0001.

Fig 3: NLRP3 may mediate SMAD4 release to the plasma. (A) Correlation between sSMAD4 and TF plasma concentration in patients from the RC cohort (n = 50) assessed by ELISA. (B) Correlation between SMAD4 and NLRP3 intracellular expression in monocytes from patients from RC cohort (n = 50) assessed by flow cytometry. Spearman’s correlation coefficients (?) and p-values are shown. (C) Schematic representation of the ex vivo models, monocytes from healthy subjects (HS, n = 6) or OSA patients (OSA, n = 7) were cultured for 16 h with the presence or absence of the NLRP3 inhibitor MCC-950 (MCC) or the caspase-1 inhibitor Ac-YVAD-cmk (YVAD). (D) SMAD4 supernatant concentration from ex vivo models assessed by ELISA. Mean ± SEM is shown. Comparisons between groups were performed by Two-Way ANOVA with Bonferroni’s multiple comparison test. *: p < 0.05, **: p < 0.01.