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| Myofibroblast |
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Histological section through testicular parenchyma of a boar. 1 Lumen of Tubulus seminiferus contortus, 2 spermatids, 3 spermatocytes, 4 spermatogonia, 5 Sertoli cell, 6 Myofibroblasts, 7 Leydig cells, 8 capillaries
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| Details |
| Latin |
myofibroblastus |
| Identifiers |
| Code |
TH H2.00.03.0.01013 |
| Anatomical terminology |
A myofibroblast is a cell that is in between a fibroblast and a smooth muscle cell in phenotype.
Contents
- 1 Developmental origin
- 2 Markers
- 3 Location and function
- 3.1 Myofibroblasts in wound healing
- 4 References
Developmental origin
There are many possible ways of myofibroblast development:
- Partial smooth muscle differentiation of a fibroblastic cell
- Activation of a stellate cell (e.g. hepatic Ito cells or pancreatic stellate cells).
- Loss of contractile phenotype (or acquisition of "synthetic phenotype") of a smooth muscle cell.
- Direct myofibroblastic differentiation of a progenitor cell resident in a stromal tissue.
- Homing and recruitment of a circulating mesenchymal precursor which can directly differentiate as above or indirectly differentiate through the other cell types as intermediates.
- Epithelial to mesenchymal transdifferentiation (EMT) of an epithelial cell.
Markers
Myofibroblasts usually stain for the intermediate filament vimentin which is a general mesenchymal marker and "alpha smooth muscle actin"(human gene = ACTA2). They are positive for other smooth markers like intermediate filament type desmin in some tissues but may be negative for desmin in some others. Similar heterogeneous positivity may exist for almost every smooth muscle marker except probably a few which are positive only in contractile smooth muscles like metavinculin and smoothelin. Some myofibroblasts (esp if they have a stellate form) may also be positive for GFAP.
Location and function
Myofibroblasts are found subepithelially in many mucosal surfaces - for example, throughout almost the whole of the gastrointestinal and genitourinary tracts. Here they not only act as a regulator of the shape of the crypts and villi but also act as stem-niche cells in the intestinal crypts and as parts of atypical antigen presenting cells. They have both support as well as paracrine function in most places. In many organs like liver, lung, and kidney they are primarily involved in fibrosis. In the wound tissue they are implicated in wound strengthening by extracellular collagen fiber deposition and then wound contraction by intracellular contraction and concomitant alignment of the collagen fibers by integrin-mediated pulling on to the collagen bundles. Pericytes and renal mesangial cells are some examples of modified myofibroblast-like cells.
Myofibroblasts may interfere with the propagation of electrical signals controlling heart rhythm, leading to arrhythmia in both patients who have suffered a heart attack and in foetuses. Ursodiol is a promising drug for this condition.[1]
Myofibroblasts in wound healing
Myofibroblasts can contract by using smooth muscle type actin-myosin complex, rich in a form of actin called alpha-smooth muscle actin. These cells are then capable of speeding wound repair by contracting the edges of the wound.
Early work on wound healing showed that granulation tissue taken from a wound could contract in vitro (or in an organ bath) in a similar fashion to smooth muscle, when exposed to substances that cause smooth muscle to contract, such as adrenaline or angiotensin.
More recently it has been shown that fibroblasts can transform into myofibroblasts with photobiomodulation.
After healing is complete, these cells are lost through apoptosis and it has been suggested that in several fibrotic diseases (for example liver cirrhosis, kidney fibrosis, retroperitoneal fibrosis) that this mechanism fails to work, leading to persistence of the myofibroblasts, and consequently expansion of the extracellular matrix (fibrosis) with contraction.
Similarly, in wounds that fail to resolve and become keloids or hypertrophic scars, myofibroblasts may persist, rather than disappearing by apoptosis.
References
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Cells in humans derived from mesoderm
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| Paraxial |
Cartilage/bone/
muscle
(MSC) |
| OCP |
| bone: |
|
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| cartilage: |
- Chondroblast → Chondrocyte
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| Myofibroblast |
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| muscle: |
- Myoblast → Myocyte
- Myosatellite cell
- Tendon cell
- Cardiac muscle cell
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| adipose: |
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| Digestive system |
- Interstitial cell of Cajal
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|
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| Intermediate |
| Urinary system (RSC) |
- Angioblast → Endothelial cell
- Mesangial cell
- Intraglomerular
- Extraglomerular
- Juxtaglomerular cell
- Macula densa cell
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- Stromal cell → Interstitial cell → Telocytes
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- Simple epithelial cell → Podocyte
- Kidney proximal tubule brush border cell
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| Reproductive system |
- Sertoli cell
- Leydig cell
- Granulosa cell
- Peg cell
- germ cells
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Lateral plate/
hemangioblast |
Blood/immune
(HSC) |
| Lymphoid (CFU-L) |
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| Myeloid (CFU-GEMM) |
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| Circulatory system |
- Endothelial progenitor cell
- Endothelial colony forming cell
- Endothelial stem cell
- Angioblast/Mesoangioblast
- Pericyte
- Mural cell
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Index of developmental medicine
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|
| Description |
- Embryology
- Cell lines
- endoderm
- mesoderm
- ectoderm
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| Disease |
- Due to toxins
- Syndromes
- Chromosomal
- Neonate
- Twins
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Histology: muscle tissue (TH H2.00.05, H3.3)
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Smooth
muscle |
- Calmodulin
- Vascular smooth muscle
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Striated
muscle |
Skeletal
muscle |
Costamere/
DAPC |
Membrane/
extracellular |
| DAP: |
- Sarcoglycan
- SGCA
- SGCB
- SGCD
- SGCE
- SGCG
- SGCZ
- Dystroglycan
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- Sarcospan
- Laminin, alpha 2
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|
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| Intracellular |
- Dystrophin
- Dystrobrevin
- Syntrophin
- Syncoilin
- Dysbindin
- Synemin/desmuslin
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| related: |
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|
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Sarcomere/
(a, i, and h bands;
z and m lines) |
- Myofilament
- thin filament/actin
- thick filament/myosin
- elastic filament/titin
- nebulin
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| Connective tissue |
- Epimysium
- Fascicle
- Perimysium
- Endomysium
- Connective tissue in skeletal muscle
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| General |
- Neuromuscular junction
- Motor unit
- Muscle spindle
- Excitation–contraction coupling
- Sliding filament mechanism
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Cardiac
muscle |
- Myocardium
- Intercalated disc
- Nebulette
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| Both |
| Fiber |
- Muscle fiber
- Myofibril
- Microfilament/Myofilament
- Sarcomere
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| Cells |
- Myoblast/Myocyte
- Myosatellite cell
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| Other |
- Desmin
- Sarcoplasm
- Sarcolemma
- Sarcoplasmic reticulum
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Other/
ungrouped |
- Myotilin
- Telethonin
- Dysferlin
- Fukutin
- Fukutin-related protein
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Index of muscle
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| Description |
- Anatomy
- head
- neck
- arms
- chest and back
- diaphragm
- abdomen
- genital area
- legs
- Muscle tissue
- Physiology
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| Disease |
- Myopathy
- Soft tissue
- Connective tissue
- Congenital
- abdomen
- muscular dystrophy
- Neoplasms and cancer
- Injury
- Symptoms and signs
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| Treatment |
- Procedures
- Drugs
- anti-inflammatory
- muscle relaxants
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Connective tissue
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| Physiology |
- Soft tissue
- Fibrosis
- Scarring
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| Composition |
| Cells |
| Resident |
- Fibroblast
- Fibrocyte
- Reticular cell
- Tendon cell
- Adipocyte
- Melanocyte
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| Wandering cells |
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Extracellular
matrix |
| Ground substance |
|
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| Fibers |
- Collagen fibers
- Reticular fibers: COL3A1
- Elastic fibers: Elastin
- Fibrillin
- EMILIN1
- Elaunin
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| Classification |
| Proper |
| Loose |
|
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| Dense |
- Dense irregular connective tissue
- Dense regular connective tissue
- Ligament
- Tendon
- Aponeurosis
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| Embryonic |
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| Specialized |
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Index of skin
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|
| Description |
- Anatomy
- Physiology
- Development
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| Disease |
- Infections
- Vesiculobullous
- Dermatitis and eczema
- Papulosquamous
- Urticaria and erythema
- Radiation-related
- Pigmentation
- Mucinoses
- Keratosis, ulcer, atrophy, and necrobiosis
- Vasculitis
- Fat
- Neutrophilic and eosinophilic
- Congenital
- Neoplasms and cancer
- nevi and melanomas
- epidermis
- dermis
- Symptoms and signs
- Terminology
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| Treatment |
- Procedures
- Drugs
- antibiotics
- disinfectants
- emollients and protectives
- itch
- psoriasis
- other
- Wound and ulcer
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Index of muscle
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| Description |
- Anatomy
- head
- neck
- arms
- chest and back
- diaphragm
- abdomen
- genital area
- legs
- Muscle tissue
- Physiology
|
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| Disease |
- Myopathy
- Soft tissue
- Connective tissue
- Congenital
- abdomen
- muscular dystrophy
- Neoplasms and cancer
- Injury
- Symptoms and signs
|
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| Treatment |
- Procedures
- Drugs
- anti-inflammatory
- muscle relaxants
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