tissue remodeling

{{Short description|Reorganization of tissues}}

Tissue remodeling is the reorganization or renovation of existing tissues. Tissue remodeling can be either physiological or pathological. The process can either change the characteristics of a tissue such as in blood vessel remodeling, or result in the dynamic equilibrium of a tissue such as in bone remodeling. Macrophages repair wounds and remodel tissue by producing extracellular matrix and proteases to modify that specific matrix.{{cite journal | vauthors=Lee BC, Lee J | title=Cellular and molecular players in adipose tissue inflammation in the development of obesity-induced insulin resistance | journal=Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease | volume=1842 | issue=3 | pages=446–462 | year=2014 | doi= 10.1016/j.bbadis.2013.05.017 | pmc=3800253 | pmid = 23707515 }}

A myocardial infarction induces tissue remodeling of the heart in a three-phase process: inflammation, proliferation, and maturation. Inflammation is characterized by massive necrosis in the infarcted area. Inflammatory cells clear the dead cells. In the proliferation phase, inflammatory cells die by apoptosis, being replaced by myofibroblasts which produce large amounts of collagen. In the maturation phase, myofibroblast numbers are reduced by apoptosis, allowing for infiltration by endothelial cells (for blood vessels) and cardiomyocytes (heart tissue cells). Usually, however, much of the tissue remodeling is pathological, resulting in a large amount of fibrous tissue.{{cite journal | vauthors=Talman V, Ruskoaho H | title=Cardiac fibrosis in myocardial infarction-from repair and remodeling to regeneration | journal= Cell and Tissue Research | volume=365 | issue=3 | pages=563–581 | year=2016 | doi= 10.1007/s00441-016-2431-9 | pmc=5010608 | pmid = 27324127 }} By contrast, aerobic exercise can produce beneficial cardiac tissue remodeling in those suffering from left ventricular hypertrophy.{{cite journal | vauthors=Fernandes T, Baraúna VG, Negrão CE, Phillips MI, Oliveira EM | title=Aerobic exercise training promotes physiological cardiac remodeling involving a set of microRNAs | journal= American Journal of Physiology. Heart and Circulatory Physiology | volume=309 | issue=4 | pages=H543–H552 | year=2015 | doi= 10.1152/ajpheart.00899.2014 | pmc=4537939 | pmid = 26071549 }}

Programmed cellular senescence contributes to beneficial tissue remodeling during embryonic development of the fetus.{{cite journal | vauthors = Khosla S, Farr JN, Tchkonia T, Kirkland JL | title = The role of cellular senescence in ageing and endocrine disease | journal = Nature Reviews Endocrinology | volume = 16 | issue=5 | pages = 263–275 | date=2020 | doi = 10.1038/s41574-020-0335-y | pmc=7227781 | pmid = 32161396}}

In a brain stroke the penumbra area surrounding the ischemic event initially undergoes a damaging remodeling, but later transitions to a tissue remodeling characterized by repair.{{cite journal | author= Lo EH | title=A new penumbra: transitioning from injury into repair after stroke | journal=Nature Medicine | volume=14 | issue=5| pages=497–500 | year=2008 | doi = 10.1038/nm1735 | pmid=18463660| s2cid=205385488 }}

Vascular remodeling refers to a compensatory change in blood vessel walls due to plaque growth. Vascular expansion is called positive remodeling, whereas vascular constriction is called negative remodeling.{{cite journal | vauthors=Lee CS, Seo YH, Yang DJ, Kim KH, Park HW, Yuk HB, Lee MS, Kim WH, Kwon TG, Bae JH | title=Positive Vascular Remodeling in Culprit Coronary Lesion is Associated With Plaque Composition: An Intravascular Ultrasound-Virtual Histology Study | journal= Korean Circulation Journal | volume=42 | issue=11 | pages=747–752 | year=2012 | doi= 10.4070/kcj.2012.42.11.747 | pmc=3518708 | pmid = 23236326 }}

Tissue remodeling occurs in adipose tissue with increased body fat.{{cite journal | vauthors=Itoh M, Suganami T, Hachiya R, Ogawa Y | title=Adipose tissue remodeling as homeostatic inflammation | journal= International Journal of Inflammation | volume=2011 | pages=720926 | year=2011 | doi= 10.4061/2011/720926 | pmc=3132651 | pmid = 21755030 | doi-access=free }} In obese subjects, this remodeling is often pathological, characterized by excessive inflammation and fibrosis.{{cite journal | vauthors=Choe SS, Huh JY, Hwang IJ, Kim JI, Kim JB | title=Adipose Tissue Remodeling: Its Role in Energy Metabolism and Metabolic Disorder | journal= Frontiers in Endocrinology| volume=7 | pages=30 | year=2016 | doi= 10.3389/fendo.2016.00030 | pmid=27148161 | pmc=4829583 | doi-access=free }}