See also
Look up fibrocyte in Wiktionary, the free dictionary.
| Fibrocyte | |
|---|---|
| Details | |
| Location | Mesenchyme |
| Function | Inactive |
| Identifiers | |
| Latin | fibrocytus |
| TH | H2.00.03.0.01003 |
| FMA | 63879 |
| Anatomical terms of microanatomy | |
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. Fibroblasts are activated connective tissue cells characterized by synthesis of proteins of the fibrous matrix, particularly the collagens. 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. [1] [2] [3]
A fibroblast is a type of biological cell typically with a spindle shape that synthesizes the extracellular matrix and collagen, produces the structural framework (stroma) for animal tissues, and plays a critical role in wound healing. Fibroblasts are the most common cells of connective tissue in animals.
A scar is an area of fibrous tissue that replaces normal skin after an injury. Scars result from the biological process of wound repair in the skin, as well as in other organs, and tissues of the body. Thus, scarring is a natural part of the healing process. With the exception of very minor lesions, every wound results in some degree of scarring. An exception to this are animals with complete regeneration, which regrow tissue without scar formation.
Fibronectin is a high-molecular weight glycoprotein of the extracellular matrix that binds to membrane-spanning receptor proteins called integrins. Fibronectin also binds to other extracellular matrix proteins such as collagen, fibrin, and heparan sulfate proteoglycans.
In biology, the extracellular matrix (ECM), also called intercellular matrix (ICM), is a network consisting of extracellular macromolecules and minerals, such as collagen, enzymes, glycoproteins and hydroxyapatite that provide structural and biochemical support to surrounding cells. Because multicellularity evolved independently in different multicellular lineages, the composition of ECM varies between multicellular structures; however, cell adhesion, cell-to-cell communication and differentiation are common functions of the ECM.
Connective tissue is one of the four primary types of animal tissue, along with epithelial tissue, muscle tissue, and nervous tissue. It develops mostly from the mesenchyme, derived from the mesoderm, the middle embryonic germ layer. Connective tissue is found in between other tissues everywhere in the body, including the nervous system. The three meninges, membranes that envelop the brain and spinal cord, are composed of connective tissue. Most types of connective tissue consists of three main components: elastic and collagen fibers, ground substance, and cells. Blood, and lymph are classed as specialized fluid connective tissues that do not contain fiber. All are immersed in the body water. The cells of connective tissue include fibroblasts, adipocytes, macrophages, mast cells and leukocytes.
With physical trauma or disease suffered by an organism, healing involves the repairing of damaged tissue(s), organs and the biological system as a whole and resumption of (normal) functioning. Medicine includes the process by which the cells in the body regenerate and repair to reduce the size of a damaged or necrotic area and replace it with new living tissue. The replacement can happen in two ways: by regeneration in which the necrotic cells are replaced by new cells that form "like" tissue as was originally there; or by repair in which injured tissue is replaced with scar tissue. Most organs will heal using a mixture of both mechanisms.
Smooth (soft) muscle is one of the three major types of vertebrate muscle tissue, the other being skeletal and cardiac muscle. Nonetheless, it is found in invertebrates as well and is controlled by the autonomic nervous system. It is non-striated, so-called because it has no sarcomeres and therefore no striations. It can be divided into two subgroups, single-unit and multi-unit smooth muscle. Within single-unit muscle, the whole bundle or sheet of smooth muscle cells contracts as a syncytium.
Wound healing refers to a living organism's replacement of destroyed or damaged tissue by newly produced tissue.
Fibrosis, also known as fibrotic scarring, is a pathological wound healing in which connective tissue replaces normal parenchymal tissue to the extent that it goes unchecked, leading to considerable tissue remodelling and the formation of permanent scar tissue.
Platelet-derived growth factor (PDGF) is one among numerous growth factors that regulate cell growth and division. In particular, PDGF plays a significant role in blood vessel formation, the growth of blood vessels from already-existing blood vessel tissue, mitogenesis, i.e. proliferation, of mesenchymal cells such as fibroblasts, osteoblasts, tenocytes, vascular smooth muscle cells and mesenchymal stem cells as well as chemotaxis, the directed migration, of mesenchymal cells. Platelet-derived growth factor is a dimeric glycoprotein that can be composed of two A subunits (PDGF-AA), two B subunits (PDGF-BB), or one of each (PDGF-AB).
Stromal cells, or mesenchymal stromal cells, are differentiating cells found in abundance within bone marrow but can also be seen all around the body. Stromal cells can become connective tissue cells of any organ, for example in the uterine mucosa (endometrium), prostate, bone marrow, lymph node and the ovary. They are cells that support the function of the parenchymal cells of that organ. The most common stromal cells include fibroblasts and pericytes. The term stromal comes from Latin stromat-, "bed covering", and Ancient Greek στρῶμα, strôma, "bed".
A myofibroblast is a cell phenotype that was first described as being in a state between a fibroblast and a smooth muscle cell.
CTGF, also known as CCN2 or connective tissue growth factor, is a matricellular protein of the CCN family of extracellular matrix-associated heparin-binding proteins. CTGF has important roles in many biological processes, including cell adhesion, migration, proliferation, angiogenesis, skeletal development, and tissue wound repair, and is critically involved in fibrotic disease and several forms of cancers.
Cysteine-rich angiogenic inducer 61 (CYR61) or CCN family member 1 (CCN1), is a matricellular protein that in humans is encoded by the CYR61 gene.
Infantile digital fibromatosis (IDF), also termed inclusion body fibromatosis or Reye's tumor, usually occurs as a single, small, asymptomatic, nodule in the dermis on a finger or toe of infants and young children. IMF is a rare disorder with approximately 200 cases reported in the medical literature as of 2021. The World Health Organization in 2020 classified these nodules as a specific benign tumor type in the category of fibroblastic and myofibroblastic tumors. IDF was first described by the Australian pathologist Douglas Reye in 1965.
In medicine, desmoplasia is the growth of fibrous connective tissue. It is also called a desmoplastic reaction to emphasize that it is secondary to an insult. Desmoplasia may occur around a neoplasm, causing dense fibrosis around the tumor, or scar tissue (adhesions) within the abdomen after abdominal surgery.
Pancreatic stellate cells (PaSCs) are classified as myofibroblast-like cells that are located in exocrine regions of the pancreas. PaSCs are mediated by paracrine and autocrine stimuli and share similarities with the hepatic stellate cell. Pancreatic stellate cell activation and expression of matrix molecules constitute the complex process that induces pancreatic fibrosis. Synthesis, deposition, maturation and remodelling of the fibrous connective tissue can be protective, however when persistent it impedes regular pancreatic function.
Dermal fibroblasts are cells within the dermis layer of skin which are responsible for generating connective tissue and allowing the skin to recover from injury. Using organelles, dermal fibroblasts generate and maintain the connective tissue which unites separate cell layers. Furthermore, these dermal fibroblasts produce the protein molecules including laminin and fibronectin which comprise the extracellular matrix. By creating the extracellular matrix between the dermis and epidermis, fibroblasts allow the epithelial cells of the epidermis to affix the matrix, thereby allowing the epidermal cells to effectively join together to form the top layer of the skin.
A cancer-associated fibroblast (CAF) is a cell type within the tumor microenvironment that promotes tumorigenic features by initiating the remodelling of the extracellular matrix or by secreting cytokines. CAFs are a complex and abundant cell type within the tumour microenvironment; the number cannot decrease, as they are unable to undergo apoptosis.
Cellular angiofibroma (CAF) is a rare, benign tumor of superficial soft tissues that was first described by M. R. Nucci et al. in 1997. These tumors occur predominantly in the distal parts of the female and male reproductive systems, i.e. in the vulva-vaginal and inguinal-scrotal areas, respectively, or, less commonly, in various other superficial soft tissue areas throughout the body. CAF tumors develop exclusively in adults who typically are more than 30 years old.