The relationship between skin stretching/contraction and pathologic scarring: The important role of mechanical forces in keloid generation

Abstract

Keloids tend to occur on highly mobile sites with high tension. This study was designed to determine whether body surface areas exposed to large strain during normal activities correlate with areas that show high rates of keloid generation after wounding. Eight adult Japanese volunteers were enrolled to study the skin stretching/contraction rates of nine different body sites. Skin stretching/contraction was measured by marking eight points on each region and measuring the change in location of the marked points after typical movements. The distribution of 1,500 keloids on 483 Japanese patients was mapped. The parietal region and anterior lower leg were associated with the least stretching/contraction, while the suprapubic region had the highest stretching/contraction rate. With regard to keloid distribution, there were 733 on the anterior chest region (48.9%) and 403 on the scapular regions (26.9%). No keloids were reported on the scalp or anterior lower leg. Because these sites are rarely subjected to skin stretching/contraction, it appears that mechanical force is an important trigger that drives keloid generation even in patients who are genetically predisposed to keloids. Thus, mechanotransduction studies are useful for developing clinical approaches that reduce the skin tension around wounds or scars for the prevention and treatment of not only keloids but also hypertrophic scars.

Force generation and transmission in keloid fibroblasts: dissecting the role of mechanosensitive molecules in cell function

“…Consistent with this, it has been shown that mechanical forces can induce formation of scars (10) and keloid (11). It has long been known that skin sites that are exposed to high stretch and contraction, show enhanced susceptibility to develop keloid disease (11). This underlines the importance of mechanosensitive cell-ECM crosstalk in this disease and underscores the significance of the study of Harn et al (4).…”

Biomechanics of Scar Tissue and Uninjured Skin

“…Both skin and scar tissue structurally adapt to loading, exhibiting rapid parallel realignment of collagen in response to stretch. 17 Additionally, clinical and preclinical data demonstrate pronounced scarring in anatomical areas with high tissue tension, [18][19][20] thereby indicating that the wound environment's biomechanics can greatly influence healing outcomes. Significantly reducing tension in healing wounds could act to minimize scarring, as was recently demonstrated by using a force-modulating polymer wound dressing.…”

Risk Factors of Keloids: A Mini Review

“…(b) Generally keloids tend to occur on highly mobile sites with high tension such as shoulders, neck, and presternum [26,27]. (c) There are familial patterns of keloid distribution [11].…”