Histology and Organization of the Fascia

The diameter of collagen fibrils is a contributing factor to the functional properties of fascia. This is demonstrated by pathologies such as Dupuytren's disease, where shortening of the palmar fascia causes contracture of fingers. Cell proliferation plus overproduction of collagen are hallmarks of the disease. Excess collagen production suggests a fibrotic disorder, however Dupuytren's is different from fibrotic pathologies such as lung fibrosis, because deposited fibrils are of smaller than normal diameters, while in lung fibrosis, diameters are larger. The minor fibrillar collagens, types III and V, FACIT collagen XIV, and certain proteoglycans regulate fibril diameters during fibrillogenesis, which occurs in steps: First, short heterotypic collagen fibrils with thin diameters are made; Second, short fibril segments gain length; Third, long fibril segments attain larger diameters by fusion with adjacent fibrils. The underlying problem in Dupuytren's disease may be the initiation of a wound healing state, with synthesis of a provisional matrix, but without the subsequent remodeling that returns the tissue to normal. By comparing the extracellular matrix components of diseased fascia with normal and fibrotic tissues, we gain clues about what molecules play important roles in the function, architecture and structural integrity of healthy fascia.