Anatomy · functional reading

Myofibroblast

The myofibroblast is a connective tissue cell, most often derived from a fibroblast, that acquires the ability to contract. It helps close wounds but, if it persists, can contribute to fibrosis.

Scientific basis

Under the effect of mechanical tension and mediators such as TGF-β, fibroblasts develop contractile fibers containing α-smooth muscle actin. These myofibroblasts draw the edges of a wound together and produce collagen; they normally disappear at the end of healing (Tomasek et al., 2002; Hinz, 2007).

When they persist, their slow contraction and their matrix production can stiffen the tissue durably. Myofibroblasts have also been found in healthy human fascia; however, the fascial contraction they allow has only been measured in rat tissue, over periods ranging from several minutes to a few hours (Schleip et al., 2019).

Blue Portance / SBNFA™ reading

The SBNFA™ sees the myofibroblast as the cellular agent of the ambivalence of remodeling: the same cell repairs or stiffens depending on the context. The hypothesis that fixed, repeated stresses favor its persistence, while varied loading moves it away from that state, belongs to the SBNFA™ reading. No data show that prolonged sitting directly activates this mechanism in humans: fascial contraction has only been measured in animals.

Contribution to the analysis of sitting

Seating analysis provides no information on myofibroblasts. It describes the repetition and fixity of stresses, which are part of the mechanical context of their activity.

Not to be confused with

Fibroblast, a cell that produces and renews the matrix without marked contractile capacity; smooth muscle fiber, the muscle cell of organs and vessels; fascial fibrosis, a possible result of their persistence.

Sources and scope

Role in wound healing and fibrosis well established; the contribution of fascial contraction to human stiffness or posture remains to be demonstrated. The phrase “fascia pulls 24 hours a day” is an exaggeration.