Lyophilized Human Amnion Chorion Membrane Reduces Hypertrophic Scar Formation by Regulating TGFβ and Myofibroblasts

The authors investigated whether a lyophilized human amnion chorion membrane (LHACM), with amnion, intermediate, and chorion layers, could alter or improve hypertrophic scarring.

The authors used their previously published murine model to create human-like hypertrophic scars (HTS) by applying mechanical tension over a healing HTS wound. Treatment with subcutaneous LHACM allograft was administered before wound closure. Scars were explanted on day 19; imaged with hematoxylin & eosin, Masson trichrome, picrosirius red, and immunofluorescent staining; and analyzed with ImageJ, MATLAB, CurveAlign, and CT-FIRE.

Mechanical strain induced hypertrophic scarring, consistent with a previously validated model, and served as a basis for evaluating the effects of LHACM treatment. Mechanical strain created wider, deeper, and denser scars compared with no strain controls. Picrosirius red analysis showed that LHACM altered collagen fiber architecture, promoting fibers that were less aligned, straight, and wide than controls. Mechanical strain increased transforming growth factor-β (TGFβ) and α-smooth muscle actin myofibroblast signaling, whereas treatment with LHACM reduced TGFβ and α-smooth muscle actin expression.

Subcutaneous treatment with LHACM significantly reduced gross and histologic scar formation and improved collagen fiber arrangement by altering TGFβ and myofibroblast expression. Because available preventative options for HTS remain limited, commercially available LHACM could potentially be used clinically in high-tension wound sites to prevent or treat HTS.

Hypertrophic scars, common after surgery, trauma, or burns, often cause physical and cosmetic impairments with limited preventive options. LHACM may serve as a potential option to mitigate hypertrophic scarring in high-tension areas after injury.