Fig. 1.

Histological evaluation of early postoperative human intestinal anastomosis

a Overview scan of Masson’s trichrome-stained histologic section of human anastomosis (double-layered inverted hand-sewn jejuno-jejunal anastomosis) at postoperative day (POD) 7 shows serosal scar formation sealing the anastomosis. The mucosal, submucosal and muscularis layers are not closed yet. Scale bar = 1000 µm, 400× magnification. b Immunofluorescence staining for fibronectin (FN1) and type I collagen (COL1) of the same human anastomosis as in a shows pronounced serosal scarring and accumulation of the extracellular matrix (ECM) proteins fibronectin and type I collagen. Scale bar = 1000 µm, 100× magnification (top), scale bar = 50 µm, 200× magnification (bottom). c Schematic representation of serosal scar formation of a double-layered inverted hand-sewn anastomosis on the day of surgery and on POD 7.