Jeffrey S. Orringer

Molecular Effects of Photodynamic Therapy for Photoaging

OBJECTIVE To quantitatively examine the epidermal and dermal cellular and molecular changes that occur after photodynamic therapy of photodamaged human skin. DESIGN Serial in vivo biochemical and immunohistochemical analyses after photodynamic therapy using topical 5-aminolevulinic acid (5-ALA) and pulsed-dye laser treatment. SETTING Academic referral center, Department of Dermatology, University of Michigan, Ann Arbor. PATIENTS A volunteer sample of 25 adults, 54 to 83 years old, with clinically apparent photodamage of the forearm skin. INTERVENTIONS Three-hour application of 5-ALA followed by pulsed-dye laser therapy using non-purpura-inducing settings to focal areas of photodamaged forearms and serial biopsy specimens taken at baseline and various times after treatment. MAIN OUTCOME MEASURES Immunohistochemical analysis was used to assess levels of markers of epidermal proliferation (Ki67), epidermal injury (cytokeratin 16), and photodamage (p53), as well as various markers of dermal collagen production (including prolyl 4-hydroxylase and heat shock protein 47, and type I procollagen). Real-time reverse transcriptase-polymerase chain reaction technology was used to quantify type I and type III collagen. Type I procollagen protein was quantified with enzyme-linked immunosorbent assay. RESULTS Epidermal proliferation was stimulated as demonstrated by increases in Ki67 (more than a 5-fold increase; P < .05) and epidermal thickness (more than a 1.4-fold increase; P < .05). Epidermal injury was produced with increased cytokeratin 16 levels demonstrated (to nearly 70-fold of baseline levels; P < .05). Upregulation of collagen production was demonstrated with increases in procollagen I messenger RNA (2.65-fold; P < .05), procollagen III messenger RNA (3.32-fold; P < .05), and procollagen I protein (2.42-fold; P < .05) levels detected. The baseline epidermal p53 level correlated with cytokeratin 16 levels at acute time points, and the latter were found to correlate with peak collagen production. CONCLUSIONS Photodynamic therapy with the specific treatment regimen employed produces statistically significant quantitative cutaneous molecular changes (eg, production of types I and III collagen) that are associated with improved appearance of the skin. Baseline epidermal p53 immunostaining levels may be predictive of dermal responses to this therapy. Comparison with historical data using pulsed-dye laser therapy alone suggests that use of the photosensitizer may enhance dermal remodeling. The quantitative in vivo molecular data presented herein are in keeping with an evolving model to potentially predict the efficacy of new techniques for the treatment of photoaging.

Enhancing Structural Support of the Dermal Microenvironment Activates Fibroblasts, Endothelial Cells, and Keratinocytes in Aged Human Skin In Vivo

The dermal extracellular matrix (ECM) provides strength and resiliency to skin. The ECM consists mostly of type I collagen fibrils, which are produced by fibroblasts. Binding of fibroblasts to collagen fibrils generates mechanical forces, which regulate cellular morphology and function. With aging, collagen fragmentation reduces fibroblast-ECM binding and mechanical forces, resulting in fibroblast shrinkage and reduced function including collagen production. Here, we report that these age-related alterations are largely reversed by enhancing structural support of the ECM. Injection of dermal filler, cross-linked hyaluronic acid, into the skin of persons over seventy years-old stimulates fibroblasts to produce type I collagen. This stimulation is associated with localized increased of mechanical forces, indicated by fibroblast elongation/spreading, and mediated by up-regulation of type II TGF-β receptor and connective tissue growth factor. Interestingly, enhanced mechanical support of the ECM also stimulates fibroblast proliferation, expands vasculature, and increases epidermal thickness. Consistent with our observations in human skin, injection of filler into dermal equivalent cultures causes elongation of fibroblasts, coupled with type I collagen synthesis, which is dependent on the TGF-β signaling pathway. Thus, fibroblasts in aged human skin retain their capacity for functional activation, which is restored by enhancing structural support of the ECM.

Eccrine Sweat Glands are Major Contributors to Reepithelialization of Human Wounds

Eccrine sweat glands are skin-associated epithelial structures (appendages) that are unique to some primates including humans and are absent in the skin of most laboratory animals including rodents, rabbits, and pigs. On the basis of the known importance of other skin appendages (hair follicles, apocrine glands, and sebaceous glands) for wound repair in model animals, the present study was designed to assess the role of eccrine glands in the repair of wounded human skin. Partial-thickness wounds were generated on healthy human forearms, and epidermal repair was studied in skin biopsy samples obtained at precise times during the first week after wounding. Wound reepithelialization was assessed using immunohistochemistry and computer-assisted 3-dimensional reconstruction of in vivo wounded skin samples. Our data demonstrate a key role for eccrine sweat glands in reconstituting the epidermis after wounding in humans. More specifically, (i) eccrine sweat glands generate keratinocyte outgrowths that ultimately form new epidermis; (ii) eccrine sweat glands are the most abundant appendages in human skin, outnumbering hair follicles by a factor close to 3; and (iii) the rate of expansion of keratinocyte outgrowths from eccrine sweat glands parallels the rate of reepithelialization. This novel appreciation of the unique importance of eccrine sweat glands for epidermal repair may be exploited to improve our approaches to understanding and treating human wounds.

Reasons for Removal of Rigid Internal Fixation Devices in Craniofacial Surgery

Despite the widespread use of rigid fixation techniques in craniofacial surgery, there is a paucity of studies in the literature that serve to better define the reasons for the subsequent removal of plates and screws. The current study appears to be the first to attempt to assess these issues among a broad range of craniofacial surgery patients. Fifty-five patients who underwent hardware removal following craniofacial surgery at the University of Michigan Medical Center between 1989 and 1995 were retrospectively studied via an in-depth chart review. Common reasons for hardware removal included palpable/prominent hardware in 19 patients (34.5%), loosening of plates and screws in 14 patients (25.5%), pain in 14 patients (25.5%), infection in 13 patients (23.6%), wound dehiscence/exposure of hardware in 11 patients (20%), and removal at the time of secondary procedures in 5 patients (9.1%). It is hoped that this study will serve as a tool to define more completely the risk of needing subsequent hardware removal among craniofacial surgery patients treated with rigid internal fixation.

Molecular mechanisms of nonablative fractionated laser resurfacing

Background  Nonablative fractionated laser resurfacing improves the texture of treated skin, but little is known about the molecular mechanisms that underlie clinical improvements.

Microdermabrasion: an evidence-based review.

Summary: Microdermabrasion is a popular technique used in the treatment of several skin problems, including acne, acne scarring, striae distensae, and photoaging. This article will review the relevant literature and use an evidence-based approach to evaluate the clinical efficacy of microdermabrasion in skin care. In summary, microdermabrasion appears to be a procedure that can produce changes in dermal matrix constituents and result in improvement in skin contour irregularities. It may also be beneficial in improving transepidermal delivery of certain medications. Its role in the treatment of dyschromias and acne vulgaris is limited.

Computer-assisted alignment and tracking of acne lesions indicate that most inflammatory lesions arise from comedones and de novo

BACKGROUND Inflammatory acne lesions are believed to derive from comedones; however, their evolution has not been rigorously studied. OBJECTIVE To examine the evolution of facial acne lesions using serial digital photographs and spatial alignment software. METHODS Six predefined lesion types, including inflammatory lesions, were counted and tracked from photographs taken every 2 weeks for 12 weeks from 25 individuals with untreated facial acne. RESULTS Closed comedones occurred most frequently (37%), followed by erythematous macules (26%), inflammatory papules (15%), open comedones (12%), pustules (2%), and nodules (1%). Inflammatory lesions were preceded by comedones (54%), normal-appearing skin (28%), erythematous macules (12%), and scars (6%). LIMITATIONS Lesions could have appeared and resolved within the 2-week intervals and some comedones may have been too small to identify on digital photographs. CONCLUSION Our results confirm the comedonal origin of the majority of inflammatory acne lesions. However, a sizeable number (28%) appear to arise from normal skin.

Molecular Analysis of Aggressive Microdermabrasion in Photoaged Skin

OBJECTIVE To investigate dermal remodeling effects of crystal-free microdermabrasion on photodamaged skin. DESIGN Biochemical analyses of human skin biopsy specimens following microdermabrasion treatment in vivo. SETTING Academic referral center. PARTICIPANTS Volunteer sample of 40 adults, aged 50 to 83 years, with clinically photodamaged forearms. Intervention Focal microdermabrasion treatment with diamond-studded handpieces of varying abrasiveness on photodamaged forearms and serial biopsies at baseline and various times after treatment. MAIN OUTCOME MEASURES Quantitative polymerase chain reaction, immunohistochemistry, and enzyme-linked immunosorbent assay were used to quantify changes in inflammatory, proliferative, and remodeling effectors of normal wound healing. Type I and type III procollagen served as the main outcome marker of dermal remodeling. RESULTS Coarse-grit microdermabrasion induces a wound healing response characterized by rapid increase in induction of cytokeratin 16 and activation of the AP-1 transcription factor in the epidermis. Early inflammation was demonstrated by induction of inflammatory cytokines, antimicrobial peptides, and neutrophil infiltration in the dermis. AP-1 activation was followed by matrix metalloproteinase-mediated degradation of extracellular matrix. Consistent with this wound-healing response, we observed significant remodeling of the dermal component of the skin, highlighted by induction of type I and type III procollagen and by induction of collagen production enhancers heat shock protein 47 and prolyl 4-hydroxylase. Dermal remodeling was not achieved when microdermabrasion was performed using a medium-grit handpiece. CONCLUSIONS Microdermabrasion using a coarse diamond-studded handpiece induces a dermal remodeling cascade similar to that seen in incisional wound healing. Optimization of these molecular effects is likely the result of more aggressive treatment with a more abrasive handpiece.

Photodynamic therapy for acne vulgaris: a randomized, controlled, split-face clinical trial of topical aminolevulinic acid and pulsed dye laser therapy.

Background  There remains the need for more effective therapeutic options to treat acne vulgaris. Interest in light‐based acne treatments has increased, but few randomized, controlled clinical trials assessing the value of photodynamic therapy (PDT) for acne have been reported.

Topical fluorouracil for actinic keratoses and photoaging: a clinical and molecular analysis.

OBJECTIVE To examine clinical and molecular changes after topical fluorouracil treatment of photodamaged human facial skin for actinic keratoses. DESIGN Nonrandomized, open-label 2-week treatment with fluorouracil cream, 5%, followed by clinical and molecular evaluation. SETTING Academic referral center. PATIENTS Twenty-one healthy volunteers, 56 to 85 years old, with actinic keratoses and photodamage. Interventions Twice-daily application of fluorouracil cream for 2 weeks and biopsies and clinical evaluation at baseline and periodically after treatment. MAIN OUTCOME MEASURES Gene and protein expression of molecular effectors of epidermal injury, inflammation, and extracellular matrix remodeling 24 hours after fluorouracil treatment; clinical improvement measured by evaluators, photography, and patient questionnaires. RESULTS One day after the final fluorouracil treatment, gene expression of the effectors of epidermal injury (keratin 16), inflammation (interleukin 1beta), and extracellular matrix degradation (matrix metalloproteinases 1 and 3) was significantly increased. Types I and III procollagen messenger RNA were induced at week 4 (7-fold and 3-fold, respectively). Type I procollagen protein levels were increased 2-fold at week 24. Actinic keratoses and photoaging were statistically significantly improved. Most patients rated photoaging as improved and were willing to undergo the therapy again. CONCLUSIONS Topical fluorouracil causes epidermal injury, which stimulates wound healing and dermal remodeling resulting in improved appearance. The mechanism of topical fluorouracil in photoaged skin follows a predictable wound healing pattern of events reminiscent of that seen with laser treatment of photoaging.