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Background: Various minimally invasive treatments enhance the skin's appearance. Little is known about the molecular mechanisms whereby treatments working at the epidermal level might alter the dermis., Objective: We sought to quantify the molecular changes that result from erbium:yttrium-aluminium-garnet (Er:YAG) laser microablative resurfacing., Methods: We performed biochemical analyses after intraepidermal Er:YAG laser resurfacing of 10 patients. Immunohistochemical analysis and polymerase chain reaction technology were utilized to measure key biomarkers., Results: The basement membrane remained intact after intraepidermal microablation, as demonstrated by laminin γ2 immunostaining. Epidermal injury was demonstrated with acute up-regulation of keratin 16. An inflammatory response ensued as indicated by increases in cytokines interleukin 1 beta (IL-1β) and IL-8 as well as a substantial neutrophil infiltrate. Levels of cJun and JunB proteins, components of the transcription factor AP-1 complex, were also elevated. Up-regulation of extracellular matrix degrading proteinases matrix metalloproteinase 1 (MMP-1), MMP-3, and MMP-9 was noted. A transient increase in keratinocyte proliferation, as indicated by staining for Ki67, was observed. Increased expression of type I and type III procollagen was demonstrated., Limitations: The data presented are those that resulted from a single treatment session., Conclusions: Although microablation was confined to the uppermost epidermis, marked changes in epidermal and dermal structure and function were demonstrated after Er:YAG laser microablative resurfacing. We demonstrated substantial dermal matrix remodeling, including a degree of collagen production that compares favorably with some more invasive interventions. Dermal remodeling and stimulation of collagen production are associated with wrinkle reduction. Thus these results suggest that the skin's appearance may be enhanced by creating dermal changes through the use of superficially acting treatments., (Copyright © 2010 American Academy of Dermatology, Inc. Published by Mosby, Inc. All rights reserved.)

Background: There is a need for additional effective treatments for acne vulgaris. Laser therapy has been explored as a therapeutic option for acne, but rigorously designed studies in this area have been limited., Objective: We sought to examine the efficacy of an infrared laser in the treatment of acne., Methods: We conducted a randomized, controlled, single-blind, split-face clinical trial of 46 patients with facial acne. Patients received a series of 3 nonablative laser treatments using a novel neodymium:yttrium-aluminum-garnet (Nd:YAG) laser to half of the face. Serial blinded lesion counts and global acne severity rating of standardized bilateral patient photographs were performed. Sebum production was measured, and patient self-assessment surveys were administered., Results: A transient but statistically significant improvement in lesion counts of open comedones was demonstrated in treated skin as compared with untreated skin. There were no significant differences between treated and control sides of the face in terms of changes in mean papule or pustule counts. Grading of serial photographs revealed no significant differences between treated and untreated skin. Patient surveys indicated that the majority of patients found the treatments to be at least mildly effective for both acne and oiliness., Limitations: The current study only addresses the efficacy of a single laser system employing a specific treatment regimen., Conclusions: Infrared laser therapy may improve comedonal acne. Additional work is needed to better define the degree and duration of the effect. Patients appear to positively view such therapy for both acne and oily skin.

Background: The mechanisms involved in laser-mediated hair removal remain unclear. One means of reducing hair growth is alteration of follicular stem cells., Objective: We sought to examine the effects of laser hair removal on the immunohistochemical staining properties of human hair follicles, including the putative stem cells of the bulge region., Methods: Treatment of unwanted axillary hair was performed on one side using an 800 nm-wavelength diode laser and on the other side using a 1064 nm-wavelength neodymium:yttrium-aluminum-garnet laser. Serial skin samples were obtained at baseline and various times after treatment and stained using immunohistochemical techniques., Results: Hair shafts were thermally altered, but the immunostaining properties of much of the follicle, including the bulge region, remained generally unchanged., Limitations: This study only addressed the acute immunohistochemical changes found after a single treatment using specific laser parameters., Conclusions: Laser-mediated hair removal does not appear to work by frank destruction of follicular stem cells. Other mechanisms including functional alteration of these cells may underlie the clinical efficacy of the procedure.

Objective: Nonablative laser therapy is widely practiced for cutaneous rejuvenation. We sought to quantify dermal molecular changes after exposure of photodamaged skin to nonablative laser energy., Methods: Nonablative laser therapy of forearm skin using either a 585-nm wavelength pulsed dye laser or a 1320-nm wavelength neodymium:yttrium-aluminum-garnet laser was performed. Serial biopsy specimens were obtained at baseline and various times after treatment., Results: Statistically significant increases in type I procollagen messenger RNA expression occurred after exposure of photodamaged skin to each laser. Induction was 47% (P < .05) and 84% (P < .05) above baseline levels 1 week after laser therapy among those treated with the pulsed dye and neodymium:yttrium-aluminum-garnet lasers, respectively. Substantial induction of type III procollagen, various matrix metalloproteinases, and primary cytokines was also demonstrated. Responses with respect to all molecules studied were highly variable., Limitations: This study addresses molecular changes after a single laser exposure whereas clinically, serial treatments are often provided., Conclusions: Nonablative laser therapy may result in quantifiable alterations in molecules associated with remodeling of the dermal matrix, although responses vary greatly among patients.

Background: Tretinoin is often prescribed before laser resurfacing in an attempt to enhance results., Objective: We sought to assess the clinical and biochemical effects of preoperative tretinoin use before laser resurfacing., Methods: Patients were randomized to apply tretinoin to one forearm and placebo to the other for 3 weeks. Patients' photodamaged forearms were focally treated by carbon-dioxide laser resurfacing. Biopsy specimens were obtained at baseline and various times posttreatment. Real-time polymerase chain reaction technology was used to quantify messenger RNA levels of types I and III procollagen and matrix metalloproteinases-1, 3, and 9. Wounds were assessed for degree of re-epithelialization using a computer graphics-generated template. A colorimeter was used to quantify postoperative erythema., Results: No substantial differences in either biochemical markers or clinical end points were identified between tretinoin and placebo pretreated forearms., Conclusions: We found no evidence of enhanced collagen formation, accelerated re-epithelialization, or quicker resolution of postoperative erythema with tretinoin pretreatment before laser resurfacing.

Objective: To quantitatively examine the dynamics of molecular alterations involved in dermal remodeling after carbon dioxide (CO(2)) laser resurfacing of photodamaged human skin., Design: Serial in vivo biochemical analyses after laser therapy., Setting: Academic referral center, Department of Dermatology, University of Michigan, Ann Arbor. Subjects Volunteer sample of 28 adults, 48 to 76 years old, with clinically evident photodamage of the forearms. Intervention Focal CO(2) laser resurfacing of photodamaged forearms and serial biopsies at baseline and various times after treatment., Main Outcome Measures: Reverse transcriptase real-time polymerase chain reaction technology and immunohistochemistry were used to assess levels of type I and type III procollagens; matrix metalloproteinases (MMPs) 1, 3, 9, and 13; tropoelastin; fibrillin; primary cytokines interleukin 1beta and tumor necrosis factor alpha; and profibrotic cytokine transforming growth factor beta1., Results: Production of type I procollagen and type III procollagen messenger RNA peaked at 7.5 and 8.9 times baseline levels, respectively, 21 days after treatment and remained elevated for at least 6 months. Increases in messenger RNA levels of several cytokines (interleukin 1beta, tumor necrosis factor alpha, and transforming growth factor beta1) preceded and/or accompanied changes in collagen levels. Marked increases in messenger RNA levels of MMP-1 (39 130-fold), MMP-3 (1041-fold), MMP-9 (75-fold), and MMP-13 (767-fold) were noted. Levels of fibrillin and tropoelastin rose in a delayed fashion several weeks after treatment., Conclusions: The biochemical changes seen after CO(2) laser resurfacing proceed through a well-organized and highly reproducible wound healing response that results in marked alterations in dermal structure. These quantitative changes may serve as a means for comparison as other therapeutic modalities meant to improve the appearance of photodamaged skin are evaluated.

Objective To quantitatively examine changes in p53 tumor suppressor gene immunostaining after carbon dioxide (CO2) laser resurfacing of photodamaged skin to assess the potential value of this treatment in reducing the risk of progression to cutaneous carcinoma. Design Serial in vivo immunohistochemical analyses after laser therapy. Setting Academic referral center, Department of Dermatology, University of Michigan, Ann Arbor. Other Participants Volunteer sample of 11 adults, 51 to 76 years old, with clinically evident photodamage of the forearms. Intervention Focal CO2 laser resurfacing of photodamaged forearms and serial biopsies at baseline, 3 weeks, and 6 months after treatment. Main Outcome Measures Because keratinocytes with mutations in p53 or altered p53 expression stain via immunohistochemical techniques, image analysis of immunohistochemically stained sections was used to quantify p53 expression. Results Positive immunostaining for p53 in the interfollicular epidermis was noted in 8 of 11 subjects at baseline, with an average staining density of 250 cells/mm2. Average staining decreased to 3 cells/mm2 3 weeks after treatment. This decrease was sustained at 5 cells/mm2 6 months after resurfacing. Conclusions There was a consistent decrease in p53 immunostaining in the interfollicular epidermis lasting for at least 6 moths after CO2 laser resurfacing of photodamaged skin. Since p53 mutation or overexpression is observed in a majority of cases of cutaneous carcinoma, the posttreatment repopulation of the epidermis with p53-negative keratinocytes should theoretically decrease the risk of malignant progression. Further study of laser resurfacing as a prophylactic procedure in patients at high risk for skin cancer development appears warranted. [ABSTRACT FROM AUTHOR]

Context The high prevalence of acne vulgaris and its significant morbidity underscore the need for convenient, low-risk, and efficacious therapy. Treatment with various lasers has been reported to improve acne. Objective To evaluate the clinical efficacy of pulsed dye laser therapy in the treatment of acne. Design, Setting, and Patients Randomized, single-blind, controlled, split-face clinical trial of a volunteer sample of 40 patients aged 13 years or older with facial acne conducted at an academic referral center from August 2002 to September 2003. Intervention One or 2 nonpurpuric pulsed dye laser treatments to half of the face (fluence of 3 J/cm2), serial blinded clinical assessments (lesion counts), and grading of acne severity using standardized bilateral serial photographs. Main Outcome Measures Comparison of the changes in lesion counts from baseline to 12 weeks between treated and untreated sides of the face and changes in photographic evidence of acne severity as graded by a panel of dermatologists blinded to treatment assignment. Results After 12 weeks, using intent-to-treat analysis with last observation carried forward, there were no significant differences between laser-treated and untreated skin for changes in mean papule counts (-4.2 vs -2.2; P = .08), mean pustule counts (0 vs -1.0; P = .12), or mean comedone counts (2.9 vs 1.6; P = .63). Grading of serial photographs confirmed the clinical assessments, showing no significant mean (SE) differences in Leeds scores (range, 1-12) for treated skin (3.98 [0.32] at baseline and 3.94 [0.27] at week 12) compared with untreated skin (3.83 [0.32] at baseline and 3.79 [0.28] at week 12) (P>.99). Conclusions In this study, the nonpurpuric pulsed dye laser therapy did not result in significant improvement of facial acne. More research is needed before this laser therapy may be recommended as an acne treatment. [ABSTRACT FROM AUTHOR]