Table 1 Selected biomarkers of ECM and wound healing that in peer review publications have been shown to be associated with key features of PF and potentially may also be used for segregation of COVID-19 patients

C1M

MMP degraded type I collagen—type I collagen is the most abundant protein in the body, and MMPs are produced by inflammatory cells degrading the tissue resulting in C1M

yes

Yes

[25], 1

C3M

MMP degraded type III collagen—type III collagen is abundant in the interstitial ECM, and MMPs are produced by inflammatory cells degrading the tissue resulting in C3M

yes

Yes

[25]

C6M

MMP degraded type VI collagen—type VI collagen is very abundant in lung ECM, and MMPs are produced by inflammatory cells degrading the tissue resulting in C6M

yes

Yes

[25, 26]

PRO-C6

Type VI collagen formation. Also known as the collagen hormone Endotrophin

yes

No

[26]

PRO-C3

Type III collagen formation, one of the most upregulated collagens in fibrotic tissues

yes

Yes

[26]

CRPM

MMP degradaded C-reactive protein a marker of local inflammaion

Yes

Yes

[25, 26]