Fibrocytes originate from the BM and are considered to be a newly identified leukocyte subpopulation. They constitute 0.1%–0.5% of peripheral blood cells and exhibit both monocyte and fibroblast-like characteristics.
They are characterized by the expression of collagen type I, fibronectin, CD11b, CD34, and CD45 but not CD14, CD3, or CD10.
Fibrocytes were initially discovered by their rapid and specific recruitment from blood to implanted wound chambers in mice. Subsequently, they have been found in the peripheral blood, wound sites, and areas of tissue remodeling.
They have been reported to contribute to the myofibroblast population in wounds.
The number of fibrocytes has been found to be significantly increased in burn patients (up to 10% of peripheral blood mononuclear cells) compared with that of normal individuals (<0.5%). Moreover, increased amounts of fibrocytes were found in hypertrophic scar tissue located primarily in the deeper layers of the papillary dermis, and were found to produce more collagen but less collagenase, compared with fibroblasts in the top layer of the dermis, suggesting a role of fibroblasts from the deeper layer of dermis in the development of fibrosis.
It has been shown that fibrocytes are potent producers of profibrotic cytokines transforming growth factor-1 and connective tissue growth factor. In addition, fibrocytes can produce ECM molecules such as type I and III collagen and fibronectin by themselves.
Abe R, Donnelly SC, Peng T, Bucala R, Metz CN. Peripheral blood fibrocytes : differentiation pathway and migration to wound sites. J Immunol. 2001 Jun 15 ;166(12):7556-62. PubMed PMID : 11390511.->http://www.jimmunol.org/content/166...