Collagen arrangement in hepatic granuloma in mice infected with Schistosoma mansoni: dependence on fiber radiation centers

Abstract

The collagen structure of isolated and in situ liver granuloma from Swiss Webster mice infected with Schistosoma mansoni was sequentially and three-dimensionally analyzed during different times of infection (early acute, acute, transitional acute-chronic, and chronic phases) by laser scanning confocal microscopy and electron scanning variable vacuum microscopy. The initial granuloma structure is characterized by vascular collagen residues and by anchorage points (or fiber radiation centers), from where collagenous fibers are angularly shed and self-assembled. During the exudative-productive stage, the self-assembly of these fibers minimizes energy and mass through continuous tension and focal compression. The curvature or angles between collagen fibers probably depends on the fibroblastic or myofibroblastic organization of stress fibers. Gradually, the loose unstable lattice of the exudative-productive stage transforms into a highly packed and stable architecture as a result of progressive compactness. The three-dimensional architecture of granulomas provides increased tissue integrity, efficient distribution of soluble compounds and a haptotactic background to the cells.

Hepatic stereology of schistosomiasis mansoni infected-mice fed a high-fat diet

“…It is possible that such findings are associated with differences in the organization of the lattice of collagen fibers built around schistosome eggs. In liver, the schistosomal granuloma is an organized structure, where the three-dimensional arrangement of its fibers, originating from anchorage points serves to provide increased tissue integrity and efficient distribution of soluble compounds and a haptotatic background to the cells (Lenzi et al 1999).…”

Experimental models of Schistosoma mansoni infection

“…Rakasz et al (1998) found that granulomas contained numerous activated Th1 and Th0 cells but that these were under tight control. have given a detailed morphogenic and biomechanical description of granuloma development and involution and have detailed the spatial deployment of collagen fibers within the granulomas (Lenzi et al 1999).…”

Four whole-istic aspects of schistosome granuloma biology: fractal arrangement, internal regulation, autopoietic component and closure

“…Each growth unit acts as a fibrotic center as was previously described (Lenzi et al 1999). However, it is not formed by a single cell as was thought before, but it is originated in the interface between three or more cells, depending on the framework of the cellular arrangement, which determines the curvature or angles between collagen fibers (Figs 12,13).…”

“…In conclusion, the schistosome granuloma is an extremely complex system with transitory states where the fully organized structure ("little macrophagic metazoa") is literally greater than the sum of actions of its individual cells and extracellular matrix components (Lenzi et al 1999). The granuloma modulation is not only determined by immune external factors, but may also be influenced by internal constrictions and regulations that need to be better understood.…”