Fibrocyte
Encyclopedia
A fibrocyte is an inactive mesenchymal cell, that is, a cell showing minimal cytoplasm, limited amounts of rough endoplasmic reticulum
and lacks biochemical evidence of protein synthesis.
The term fibrocyte contrasts with the term fibroblast. Fibroblast
s are activated connective tissue
cells characterized by synthesis of proteins of the fibrous matrix, particularly the collagen
s. When tissue is injured, the predominant mesenchymal cells, the fibroblast, have been believed to be derived from the fibrocyte or possibly from smooth muscle
cells lining vessels and glands. Commonly, fibroblasts express smooth muscle actin
, a form of actin first found in smooth muscle cells and not found in resting fibrocytes. Fibroblasts expressing this form of actin are usually called "myo-fibroblasts."
Recently, the term "fibrocyte" has also been applied to a bloodborne cell able to leave the blood, enter tissue and become a fibroblast. As part of the more general topic of stem cell biology, a number of studies have suggested that the blood contains marrow derived cells that can differentiate into fibroblasts. These cells have been reported to express the hematopoietic cell surface markers CD34+, CD45+, as well as collagen
. These cells can migrate to wound sites, suggesting a role in wound healing
. There are several studies suggesting that fibrocytes mediate wound healing and fibrotic tissue repair.
Endoplasmic reticulum
The endoplasmic reticulum is an organelle of cells in eukaryotic organisms that forms an interconnected network of tubules, vesicles, and cisternae...
and lacks biochemical evidence of protein synthesis.
The term fibrocyte contrasts with the term fibroblast. Fibroblast
Fibroblast
A fibroblast is a type of cell that synthesizes the extracellular matrix and collagen, the structural framework for animal tissues, and plays a critical role in wound healing...
s are activated connective tissue
Connective tissue
"Connective tissue" is a fibrous tissue. It is one of the four traditional classes of tissues . Connective Tissue is found throughout the body.In fact the whole framework of the skeleton and the different specialized connective tissues from the crown of the head to the toes determine the form of...
cells characterized by synthesis of proteins of the fibrous matrix, particularly the collagen
Collagen
Collagen is a group of naturally occurring proteins found in animals, especially in the flesh and connective tissues of mammals. It is the main component of connective tissue, and is the most abundant protein in mammals, making up about 25% to 35% of the whole-body protein content...
s. When tissue is injured, the predominant mesenchymal cells, the fibroblast, have been believed to be derived from the fibrocyte or possibly from smooth muscle
Smooth muscle
Smooth muscle is an involuntary non-striated muscle. It is divided into two sub-groups; the single-unit and multiunit smooth muscle. Within single-unit smooth muscle tissues, the autonomic nervous system innervates a single cell within a sheet or bundle and the action potential is propagated by...
cells lining vessels and glands. Commonly, fibroblasts express smooth muscle actin
Actin
Actin is a globular, roughly 42-kDa moonlighting protein found in all eukaryotic cells where it may be present at concentrations of over 100 μM. It is also one of the most highly-conserved proteins, differing by no more than 20% in species as diverse as algae and humans...
, a form of actin first found in smooth muscle cells and not found in resting fibrocytes. Fibroblasts expressing this form of actin are usually called "myo-fibroblasts."
Recently, the term "fibrocyte" has also been applied to a bloodborne cell able to leave the blood, enter tissue and become a fibroblast. As part of the more general topic of stem cell biology, a number of studies have suggested that the blood contains marrow derived cells that can differentiate into fibroblasts. These cells have been reported to express the hematopoietic cell surface markers CD34+, CD45+, as well as collagen
Collagen
Collagen is a group of naturally occurring proteins found in animals, especially in the flesh and connective tissues of mammals. It is the main component of connective tissue, and is the most abundant protein in mammals, making up about 25% to 35% of the whole-body protein content...
. These cells can migrate to wound sites, suggesting a role in wound healing
Wound healing
Wound healing, or cicatrisation, is an intricate process in which the skin repairs itself after injury. In normal skin, the epidermis and dermis exists in a steady-state equilibrium, forming a protective barrier against the external environment...
. There are several studies suggesting that fibrocytes mediate wound healing and fibrotic tissue repair.