Characterization of Mesenchymal Cell from BAL of post COVID-19 patient whit fibrosis

ABSTRACT

Increasing number of severe COVID 19 patients develop pulmonary Fibrosis, but the management of this complication is still unclear due to a lack of clinical trials. Aim of this study was to characterize mesenchymal cells (MC) isolated from 10 broncho-alveolar lavage (BAL, at 2 months after discharge) from patients with COVID19 fibrosis (COVID19-f) and to compare them with those isolated from 8 patients with collagen tissue diseaseassociated interstitial fibrosis(CTD-ILD). BAL fluid (BALf) levels of TGFbeta, VEGF, TIMP2, RANTES, IL6, IL8, and PAI1 were assessed by ELISA. Primary MC foci were cultured and expanded in D-MEM +10% FBS, characterized by flow cytometry and osteogenic and adipogenic differentiation. Collagen 1 production (+/-TGF-beta) was tested by WB and mRNA expression. BALf cytokine and GF levels were comparable in the two groups. Efficiency of MC isolation from BAL was 100% in COVID-f compared to 65% in CTD-ILD. MC antigen surface expression of CD105, CD73, CD90 (>90%, respectively), CD45, CD34, CD19 and HLA-DR (<5%, respectively) was comparable. None of MC samples differentiated in adipocytes, while COVID19-f were positive for calcium deposition. COVID19-f MC showed at WB, higher Collagen 1 production with respect to CTD-ILD with TGF-beta stimulation. Our preliminary data suggest MC from COVID19-f share several features with CTD-ILD but might have a higher response to fibrogenic and differentiation signals.