Person:

Sakamoto, Fernanda

Background: Conventional autologous skin grafts are associated with significant donor-site morbidity. This study was conducted to determine feasibility, safety, and efficacy of a new strategy for skin grafting based on harvesting small columns of full-thickness skin with minimal donor-site morbidity. Methods: The swine model was used for this study. Hundreds of full-thickness columns of skin tissue (~700 µm diameter) were harvested using a custom-made harvesting device, and then applied directly to excisional skin wounds. Healing in donor and graft sites was evaluated over 3 months by digital photographic measurement of wound size and blinded, computer-aided evaluation of histological features and compared with control wounds that healed by secondary intention or with conventional split-thickness skin grafts (STSG). Results: After harvesting hundreds of skin columns, the donor sites healed rapidly without scarring. These sites reepithelialized within days and were grossly and histologically indistinguishable from normal skin within 7 weeks. By contrast, STSG donor sites required 2 weeks for reepithelialization and retained scar-like characteristics in epidermal and dermal architecture throughout the experiment. Wounds grafted with skin columns resulted in accelerated reepithelialization compared with ungrafted wounds while avoiding the “fish-net” patterning caused by STSG. Conclusion: Full-thickness columns of skin can be harvested in large quantities with negligible long-term donor-site morbidity, and these columns can be applied directly to skin wounds to enhance wound healing.

The pathophysiology of acne vulgaris depends on active sebaceous glands, implying that selective destruction of sebaceous glands could be an effective treatment. We hypothesized that light-absorbing microparticles could be delivered into sebaceous glands, enabling local injury by optical pulses. A suspension of topically applied gold-coated silica microparticles exhibiting plasmon resonance with strong absorption at 800 nm was delivered into human pre-auricular and swine sebaceous glands in vivo, using mechanical vibration. After exposure to 10–50 J cm−2, 30 milliseconds, 800 nm diode laser pulses, microscopy revealed preferential thermal injury to sebaceous follicles and glands, consistent with predictions from a computational model. Inflammation was mild; gold particles were not retained in swine skin 1 month after treatment, and uptake in other organs was negligible. Two independent prospective randomized controlled clinical trials were performed for treatment of moderate-to-severe facial acne, using unblinded and blinded assessments of disease severity. Each trial showed clinically and statistically significant improvement of inflammatory acne following three treatments given 1–2 weeks apart. In Trial 2, inflammatory lesions were significantly reduced at 12 weeks (P=0.015) and 16 weeks (P=0.04) compared with sham treatments. Optical microparticles enable selective photothermolysis of sebaceous glands. This appears to be a well-tolerated, effective treatment for acne vulgaris.

We report the synthesis and application of an elastic, wearable crosslinked polymer layer (XPL) that mimics the properties of normal, youthful skin. XPL is made of a tunable polysiloxane-based material that can be engineered with specific elasticity, contractility, adhesion, tensile strength and occlusivity. XPL can be topically applied, rapidly curing at the skin interface without the need for heat- or light-mediated activation. In a pilot human study, we examined the performance of a prototype XPL that has a tensile modulus matching normal skin responses at low strain (< 40%), and that withstands elongations exceeding 250%, elastically recoiling with minimal strain-energy loss on repeated deformation. The application of XPL to the herniated lower-eyelid fat pads of 12 subjects resulted in an average 2-grade decrease in herniation appearance in a 5-point severity scale. The XPL platform may offer advanced solutions to compromised skin barrier function, pharmaceutical delivery, and wound dressings.