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Morphological features of collagen degradation in advanced hepatic schistosomiasis of man
1Centro de Pesquisas Gonçalo Moniz, Fiocruz, Salvador, Ba, Brasil.
Abstract:
Optical and electron microscopical evidences of focal matrix degradation were frequently seen in liver sections taken from patients with periportal ("pipe-stem") fibrosis caused by schistosomiasis mansoni. Besides the presence of focal areas of rarefaction, fragmentation and dispersion of collagen fibers, the enlarged portal spaces also showed hyperplasia of elastic tissue and disarray of smooth muscle fibers following the destruction of portal vein branches. Ultrastructural changes represented by focal lytic and/or electron dense alterations of collagen fibrils were similar to those first seen in experimental material and designated as "chronic collagen degradation". Elastin and related microfibrils were also affected by focal condensation, fragmentation, distortion and dissolution. Schistosome eggs were scanty in the tissue sections examined. Matrix degradation represented involuting changes related to the progressive diminution of parasite aggression, which occurs spontaneously with age or after cure by chemotherapy. Changes of focal matrix degradation now being described represent the basic morphological counterpart of periportal fibrosis involution documented clinically, especially by ultrasonography, in patients with hepatosplenic schistosomiasis submitted to curative chemotherapy.
Insights
Schistosomiasis mansoni causes liver fibrosis, but matrix degradation indicates healing. This chronic collagen degradation is key to resolving periportal fibrosis after treatment.
Area of Science:
- Pathology
- Hepatology
- Parasitology
Background:
- Schistosomiasis mansoni infection leads to periportal fibrosis in the liver.
- This fibrosis is characterized by collagen deposition and architectural distortion.
- Previous studies noted collagen changes but lacked detailed ultrastructural analysis.
Purpose of the Study:
- To investigate the ultrastructural changes in liver matrix during schistosomiasis fibrosis.
- To correlate observed matrix degradation with clinical signs of fibrosis involution.
- To understand the process of chronic collagen degradation in hepatic schistosomiasis.
Main Methods:
- Optical and electron microscopy of liver sections from patients with schistosomiasis mansoni.
- Histological examination for collagen fiber arrangement, elastic tissue, and smooth muscle.
- Ultrastructural analysis of collagen fibrils and microfibrils.
Main Results:
- Focal matrix degradation, including collagen rarefaction, fragmentation, and dispersion, was observed.
- Hyperplasia of elastic tissue and disarray of smooth muscle fibers were noted in enlarged portal spaces.
- Ultrastructural changes consistent with 'chronic collagen degradation' and elastin alterations were identified.
Conclusions:
- Focal matrix degradation represents an involuting process in hepatic schistosomiasis.
- These ultrastructural changes are the morphological basis for clinical resolution of periportal fibrosis.
- This degradation occurs spontaneously with age or after successful chemotherapy.