Pressure Effects on the Growth of Human Scar Fibroblasts

Abstract

Although pressure therapy is the mainstay of treatment for hypertrophic scars, its actual mechanism remains unknown. An in vitro study was designed to investigate the effects of positive pressure on the growth of human scar-derived fibroblasts through its transforming growth factor beta1 (TGF-beta1) secretion. A pneumatic pressure system connecting to a cell culture chamber was designed. Six-well cultured plates with fibroblasts implanted were treated with different pressure settings. Cells were treated with constant pressure 20 mm Hg above atmosphere pressure (group A n = 18) or with 40 mm Hg above atmosphere pressure (group B n = 18) daily for nine successive days. Cells without pressure were treated as the control study (group C n = 6). Each experimental group was divided into daily pressure applied at 24 hours (n = 6), 18 hours (n = 6), and 12 hours (n = 6). Cell counting was performed on the 2nd, 4th, 7th, 9th, 11th, and 14th day after implantation. On day 4, the concentration of transforming growth factor beta1 was measured, and cell doubling time was calculated. Compared with the control group, there was a significant decrease in cell count and the concentration in the 18-hour and 24-hour 20 mm Hg or 40 mm Hg pressure treated group. The cell doubling time was significantly increased in the 24-hour 20 mm Hg or 40 mm Hg pressure treated groups, and the 18-hour 40 mm Hg pressure treated group. (P < .05) Pressure inhibits the growth and activity of human scar fibroblasts, and a higher pressure application can shorten the daily application period. There should be an optimal pressure level corresponding to a daily application period to achieve the most effective results on pressure therapy for scars.

Letter

“…Pressure therapy is influential in the first 6 months while wound healing is most active. In vitro scar‐derived fibroblast growth and transforming growth factor beta 1 secretion are significantly lower within the above‐mentioned pressure system during this time interval, as described by Chang and colleagues 4 …”

“…In vitro scar-derived fibroblast growth and transforming growth factor beta 1 secretion are significantly lower within the above-mentioned pressure system during this time interval, as described by Chang and colleagues. 4 Although response rates of 90% to 100% have been reported with compression therapy after excision of earlobe keloids, 5 few studies address the frequency of recurrence using pressure alone. Perhaps one of the most frequently referenced is Brent's 1978 study involving a small series of patients with bilateral keloids who were treated with pressure earrings on one side after bilateral surgical excision.…”

Compression therapy affects collagen type balance in hypertrophic scar

“…Pressure therapy is thought to modulate changes in scar through a variety of means, such as myofibroblasts [25, 37, 38], matrix metalloproteinases [26], tumor necrosis factor-α [27], and transforming growth factor-β1 (TGF-β1) [27, 39]. Despite these studies, no unifying mechanism has been described that explains the effect of pressure therapy on hypertrophic scar and, more specifically, collagen behavior.…”

A new treatment for reliable functional and esthetic outcome after local facial flap reconstruction: a transparent polycarbonate facial mask with silicone sheeting

“…Mechanical compression by means of pressure garment therapy is a reputable modality to diminish collagen synthesis by reducing blood flow. Another hypothesis for the action of pressure therapy is a decrease in blood flow that causes hypoxia, resulting in fibroblast degeneration and loosening of collagen fibrils [ 21 , 22 ]. Pressure garment therapy has also proven to result in significant improvement in scar erythema and thickness in postburn hypertrophic scars [ 23 ].…”