Intraepidermal erbium:YAG laser resurfacing: impact on the dermal matrix

Skin rejuvenation through topical application of indocyanine green with diffractive optical element mode of 785 nm picosecond laser in Asian females

BACKGROUND

Indocyanine green (ICG) exhibits robust absorption near 800 nm.

AIMS

To examine the clinical effects of combining ICG with a 785 nm picosecond laser for treating photo-aged skin.

PATIENT/METHODS

A 785 nm 600 picosecond laser was used on the facial area of 16 female patients with Fitzpatrick skin type III and IV (mean age: 58.44 ± 5.24 years) after applying 0.0125% ICG cream. A total of 3000 shots were administered in diffractive optical element mode at a pulse energy of 200 mJ and frequency of 10 Hz. Hyperpigmented lesions were treated using the Zoom handpiece set at a spot size of 3-4 mm, pulse energy of 60-120 mJ, and frequency of 3-7 Hz. Patients underwent five sessions of treatment at intervals of 1-2 weeks. Wrinkles, pores and pigmented lesions were assessed at the initial assessment and 4 weeks after the final treatment using the Modified Fitzpatrick Wrinkle Scale and 10-point visual analog scale, respectively. Skin biopsy of the postauricular area was performed on two consenting patients.

RESULTS

Significant improvements in wrinkles (p = 0.02), pores (p = 0.034), and hyperpigmentation (p = 0.036) were observed, along with increased patient subjective improvement. Adverse effects were transient and well-tolerated. Hematoxylin and eosin and Masson's trichrome staining revealed increased and thickened dermal collagen fibers. Immunohistochemical staining revealed increased expression of collagen I and III throughout the papillary and upper reticular dermis, along with diffuse increase of STRO-1 in the dermis.

CONCLUSIONS

The combined application of a 785 nm picosecond laser and ICG yielded promising clinical outcomes for treating photo-aged skin in Asian patients with Fitzpatrick skin type III and IV.

Laser Micropatterning Promotes Rete Ridge Formation and Enhanced Engineered Skin Strength without Increased Inflammation

Rete ridges play multiple important roles in native skin tissue function, including enhancing skin strength, but they are largely absent from engineered tissue models and skin substitutes. Laser micropatterning of fibroblast-containing dermal templates prior to seeding of keratinocytes was shown to facilitate rete ridge development in engineered skin (ES) both in vitro and in vivo. However, it is unknown whether rete ridge development results exclusively from the microarchitectural features formed by ablative processing or whether laser treatment causes an inflammatory response that contributes to rete ridge formation. In this study, laser-micropatterned and non-laser- treated ES grafts were developed and assessed during culture and for four weeks post grafting onto full-thickness wounds in immunodeficient mice. Decreases in inflammatory cytokine secretion were initially observed in vitro in laser-treated grafts compared to non-treated controls, although cytokine levels were similar in both groups five days after laser treatment. Post grafting, rete ridge-containing ES showed a significant increase in vascularization at week 2, and in collagen deposition and biomechanics at weeks 2 and 4, compared with controls. No differences in inflammatory cytokine expression after grafting were observed between groups. The results suggest that laser micropatterning of ES to create rete ridges improves the mechanical properties of healed skin grafts without increasing inflammation.

Dermal Fibroblasts as the Main Target for Skin Anti-Age Correction Using a Combination of Regenerative Medicine Methods

This article includes the data from current studies regarding the pathophysiological mechanisms of skin aging and the regenerative processes occurring in the epidermis and dermis at the molecular and cellular level, mainly, the key role of dermal fibroblasts in skin regeneration. Analyzing these data, the authors proposed the concept of skin anti-age therapy that is based on the correction of age-related skin changes by stimulating regenerative processes at the molecular and cellular level. The main target of the skin anti-age therapy is dermal fibroblasts (DFs). A variant of the cosmetological anti-age program using the combination of laser and cellular methods of regenerative medicine is presented in the paper. The program includes three stages of implementation and defines the tasks and methods of each stage. Thus, laser technologies allow one to remodel the collagen matrix and create favorable conditions for DFs functions, whereas the cultivated autologous dermal fibroblasts replenish the pool of mature DFs decreasing with age and are responsible for the synthesis of components of the dermal extracellular matrix. Finally, the use of autological platelet-rich plasma (PRP) enables to maintenance of the achieved results by stimulating DF function. It has been shown that growth factors/cytokines contained in α-granules of platelets injected into the skin bind to the corresponding transmembrane receptors on the surface of DFs and stimulate their synthetic activity. Thus, the consecutive, step-by-step application of the described methods of regenerative medicine amplifies the effect on the molecular and cellular aging processes and thereby allows one to optimize and prolong the clinical results of skin rejuvenation.

Low-fluence treatment with a novel fractionated 2,910-nm fiber laser improves photodamage

BACKGROUND

Facial rejuvenation by lasers that target water has been a mainstay of esthetic laser treatments for decades. Modern lasers more commonly treat a fraction of the skin surface using ablative, semi-ablative, or nonablative pulses.

METHODS

Twenty subjects with visible evidence of chronic photoaging on the face were enrolled in this study. All subjects received two full-face, single-pass treatments spaced 2 months apart with the superficial mode of a 2910 nm fiber laser with an estimated penetration depth of 10 μm, 25% coverage, delivered in a 15 mm × 15 mm square microbeam pattern. A blinded comparison of pretreatment and 3-month post-treatment images was performed. Evaluation of biopsy samples for laser-tissue effects was performed on three separate subjects and biopsies were harvested 1-day post-treatment, 1-week post-treatment, and 2-weeks post-treatment.

RESULTS

Blinded evaluation of digital images revealed an average improvement score of 25.1 ± 14.5 (mean ± SEM) or 25.1%, using an 11-point scale evaluating overall improvement in photoaging (p < 0.001). Post-treatment effects were limited to mild-to-moderate erythema and edema, and the pain was rated a 1.9 out of a maximum of 10. Histology demonstrated superficial changes in the stratum corneum and epidermis with dermal inflammation present at 1-day post-treatment and 1-week post-treatment, with a return to baseline at 2 weeks.

CONCLUSIONS

The 2910 nm fiber laser is safe and effective for improving mild photodamage, with minimal discomfort and downtime. Dermal inflammation results from very superficial epidermal injury and may contribute to clinical improvement.

Low-level green laser promotes wound healing after carbon dioxide fractional laser therapy

BACKGROUND

The carbon dioxide (CO₂ ) fractional laser resurfacing has become one of the hottest therapies for dermatoses. However, complications such as skin swelling, prolonged erythema, post-inflammatory hyperpigmentation, and scar formation remain. Low-level laser (LLL) therapy is accepted to promote skin wound healing and regeneration, decrease inflammation and pain, and modulate immunoreaction with low-dose laser of different wavelength. 532 nm laser therapy is commonly used to remove pigmented spots and to tender skin, but not utilized in wound care.

OBJECTIVE

We aimed to determine the efficacy of the low-level 532 nm green laser in wound healing after CO₂ fractional laser.

METHODS

Six adult male mice (C57BL/6, 8 weeks old) were prepared for animal experiments. The dorsum of each mouse was divided into four parts that, respectively, received designed treatments, as controlled (group Ctrl), 532 nm LLL-treated (group GL), CO₂ fractional laser-treated (group FL), and CO₂ fractional laser followed by three times 532 nm LLL-treated (group FG). Hematoxylin-eosin staining (H&E), Masson-trichrome staining, CD31 immunohistochemical staining were performed to evaluate the efficacy of wound healing after treated by different irradiations. Western blotting was used to detect the expression of related proteins. Mouse skin fibroblasts (MSFs) were treated with LLL using a wavelength of 532 nm once. Cellular responses were observed and analyzed after 48 hours. Cell viability and migration of different groups were assessed by scratch and the Cell Counting Kit-8 (CCK8) assays, respectively.

RESULTS

Collagen remodeling and epidermis thickness were significantly enhanced in group FG than that in group FL in morphology. Besides, CD31 immunohistochemical staining indicated prominently increased angiogenesis in both groups FL and FG than non-irradiation group. The expression of extracellular matrix (ECM)-related protein (Col1, Col3 and MMP1) showed a remarkable improvement in wound healing in group FG than that in group FL. Irradiated MSFs showed a better migration ability compared with non-irradiated controls. LLL enhanced the secretion function of MSFs on Collagen I and III.

CONCLUSIONS

Low-level green laser promotes wound healing after CO₂ fractional laser by improving the integrity of skin barrier and allowing for scarless healing. Therefore, low-level green laser therapy might serve as a sequential therapy of invasive laser surgery to ensure a better wound care.

Quantitative analysis of collagen after Intense Pulsed Light and Erbium-Doped Yttrium Aluminum Garnet Laser Treatment on Rabbit Skin

OBJECTIVE

To investigate the effects of intense pulsed light (IPL) and ablative 2.940 nm erbium-doped yttrium aluminum garnet (Er: YAG) laser on dynamic changes in collagen by quantitative analysis of type I collagen (Col I) and type III collagen (Col III), transforming growth factor (TGF) and matrix metalloproteinases (MMPs) in the dermis of rabbits.

METHODS

Backs of ten rabbits were divided into four treatment areas: IPL normal energy group, IPL high energy group, erbium laser normal energy group and erbium laser high energy group. HE staining was performed immediately after the first treatment and two weeks after the first treatment. Col I, Col III, TGF-β1 and MMP-1 were collected by real-time PCR at baseline, 2 weeks after each session and three months after the entire treatment monthly.

RESULTS

HE staining showed that collagen fibers in the superficial layer of the dermis in the four treatment groups were increased and thickened to different degrees. Real-time PCR showed that statistically differences were noted in each checkpoint before and after treatments in the four groups, whereas no significant difference in the change in the four biomarkers was found among the four treatment groups.

CONCLUSION

Both the IPL and Er:YAG laser can effectively upregulate collagens, but in this experiment, there was no significant difference in the therapeutic effect among the four irradiation groups. Moreover, the high energy level group tended to bring more serious epidermal injury.

Calcium Signaling in the Photodamaged Skin: In Vivo Experiments and Mathematical Modeling

The epidermis forms an essential barrier against a variety of insults. The overall goal of this study was to shed light not only on the effects of accidental epidermal injury, but also on the mechanisms that support laser skin resurfacing with intra-epidermal focal laser-induced photodamage, a widespread medical practice used to treat a range of skin conditions. To this end, we selectively photodamaged a single keratinocyte with intense, focused and pulsed laser radiation, triggering Ca2+ waves in the epidermis of live anesthetized mice with ubiquitous expression of a genetically encoded Ca2+ indicator. Waves expanded radially and rapidly, reaching up to eight orders of bystander cells that remained activated for tens of minutes, without displaying oscillations of the cytosolic free Ca2+ concentration ([Formula: see text]). By combining in vivo pharmacological dissection with mathematical modeling, we demonstrate that Ca2+ wave propagation depended primarily on the release of ATP, a prime damage-associated molecular patterns (DAMPs), from the hit cell. Increments of the [Formula: see text] in bystander cells were chiefly due to Ca2+ release from the endoplasmic reticulum (ER), downstream of ATP binding to P2Y purinoceptors. ATP-dependent ATP release though connexin hemichannels (HCs) affected wave propagation at larger distances, where the extracellular ATP concentration was reduced by the combined effect of passive diffusion and hydrolysis due to the action of ectonucleotidases, whereas pannexin channels had no role. Bifurcation analysis suggests basal keratinocytes have too few P2Y receptors (P2YRs) and/or phospholipase C (PLC) to transduce elevated extracellular ATP levels into inositol trisphosphate (IP3) production rates sufficiently large to sustain [Formula: see text] oscillations.

Wound Healing Profile After 1064- and 532-nm Picosecond Lasers With Microlens Array of In Vivo Human Skin

BACKGROUND AND OBJECTIVES

The aim of this study is to histologically characterize the wound healing process of in vivo human skin treated with 1064- and 532-nm microlens array (MLA)-type picosecond lasers.

STUDY DESIGN/MATERIALS AND METHODS

Three patients (Fitzpatrick skin types II-IV), who were undergoing future cosmetic abdominoplasties, were treated with 1064- and 532-nm MLA-type lasers under different fluence settings. Treatments were performed 2 weeks, 1 week, and immediately prior to surgery. Skin samples were harvested from the resected tissue with 8 mm punch biopsies immediately after the abdominoplasties were performed.

RESULTS

The study demonstrates that intraepidermal vacuoles, created from tissue damage induced by the laser, are histologically resolved within 1 week without persistent damage to the dermoepidermal junction or vasculature. After 2 weeks, all foci of microscopic epidermal necrotic debris had either resolved or migrated to more superficial levels in the stratum corneum. There was no evidence of persistent vascular damage, increased melanophages, or accumulation of melanin in the dermis at 2 weeks. Furthermore, the 1064-nm picosecond laser with the high fluence setting demonstrated the capacity to fractionally ablate the epidermis and induce multifocal fibrosis in the papillary dermis in lighter skin types.

CONCLUSION

This is the first study to demonstrate the wound healing profile of in vivo human skin after treatment with the picosecond 1064- and 532-nm MLA-type lasers. It shows that laser-induced tissue damage is histologically resolved within 2 weeks, clinically reflecting a favorable safety profile and short downtime. The study also shows that the picosecond laser can be used to induce either fractional ablative or non-ablative effects, depending on the fluence settings used. Lasers Surg. Med. © 2021 Wiley Periodicals LLC.

Effects of non-ablative Er:YAG laser on the skin and the vaginal wall: systematic review of the clinical and experimental literature

INTRODUCTION AND HYPOTHESIS

Er:YAG laser is frequently used in dermatology and gynecology. Clinical studies document high satisfaction rates; however, hard data on the effects at the structural and molecular levels are limited. The aim of this systematic review was to summarize current knowledge about the objective effects of non-ablative Er:YAG laser on the skin and vaginal wall.

METHODS

We searched MEDLINE, Embase, Cochrane, and the Web of Science. Studies investigating objectively measured effects of non-ablative Er:YAG laser on the skin or vaginal wall were included. Studies of any design were included. Owing to the lack of methodological uniformity, no meta-analysis could be performed and therefore results are presented as a narrative review.

RESULTS

We identified in vitro or ex vivo studies on human cells or tissues, studies in rats, and clinical studies. Most studies were on the skin (n = 11); the rest were on the vagina (n = 4). The quality of studies is limited and the settings of the laser were very diverse. Although the methods used were not comparable, there were demonstrable effects in all studies. Immediately after application the increase in superficial temperature, partial preservation of epithelium and subepithelial extracellular matrix coagulation were documented. Later, an increase in epithelial thickness, inflammatory response, fibroblast proliferation, an increase in the amount of collagen, and vascularization were described.

CONCLUSIONS

Er:YAG laser energy may induce changes in the deeper skin or vaginal wall, without causing unwanted epithelial ablation. Laser energy initiates a process of cell activation, production of extracellular matrix, and tissue remodeling.

Comparison of a 1064-nm neodymium-doped yttrium aluminum garnet picosecond laser using a diffractive optical element vs. a nonablative 1550-nm erbium-glass laser for the treatment of facial acne scarring in Asian patients: a 17-week prospective, randomized, split-face, controlled trial

BACKGROUND

Novel picosecond lasers using a diffractive optical element (P-DOE) have been available for skin resurfacing with distinct mechanisms. However, there are limited data directly comparing P-DOE and conventional fractional lasers for the treatment of atrophic acne scarring.

OBJECTIVES

We sought to compare the efficacy and safety of a 1064-nm neodymium-doped yttrium aluminium garnet P-DOE and a non-ablative fractional laser (NAFL) in the treatment of acne scarring.

METHODS

A prospective, randomized, split-face, controlled trial was performed. One randomly assigned half-side of each patient's face (n = 25) was treated with four consecutive sessions of P-DOE at 3-week intervals and the other side with NAFL, with subsequent follow-up for 8 weeks after the final sessions. The efficacy and safety of the two lasers were determined by the Echelle d'Evaluation Clinique des Cicatrices d'acné (Scale of Clinical Evaluation of Acne Scars; ECCA) grading scale, Investigator's Global Assessment (IGA) score and patients' reports at the final visit. Histologic analysis was also performed.

RESULTS

The P-DOE-treated side achieved a significantly better improvement in acne appearance (ECCA per cent reduction: 55% vs. 42%) with less severe pain (4.3 vs. 5.6) (P < 0.05). The IGA score and subjective satisfaction were consistent with ECCA score results. Occurrences of treatment-related side-effects were also lower in the group treated with P-DOE (P < 0.05). Histologic analysis revealed elongation and increased density of neocollagen fibres, elastic fibres and mucin throughout the dermis from both sides.

CONCLUSIONS

Compared with NAFL, P-DOE afforded better clinical outcomes and fewer side-effects in the treatment of acne scarring in Asian patients.

Assessment of Laser Effects on Skin Rejuvenation

Laser skin resurfacing has changed the approach of facial skin rejuvenation over the past decade. This article evaluates the laser effects on skin rejuvenation by the assessment of laser characteristics and histological and molecular changes, accompanied by the expression of proteins during and after laser-assisted rejuvenation of skin. It is important to note that different layers of skin with different cells are normally exposed to the sun's UV radiation which is the most likely factor in aging and damaging healthy skin. To identify the expression of proteins, using validated databases and reviewing existing data could reveal altered proteins which could be analyzed and mapped to investigate their expression and their different effects on cell biological responses. In this regard, proteomics data can be used for better investigation of the changes in the proteomic profile of the treated skin. Different assessments have revealed the survival and activation of fibroblasts and new keratinocytes with an increase of collagen and elastin fibers in the dermis and the reduction of matrix metalloproteinases (MMPs) and heat shock proteins (HSPs) as a result of different low-power laser therapies of skin. There are a wide range of biological effects associated with laser application in skin rejuvenation; therefore, more safety considerations should be regarded in the application of lasers in skin rejuvenation.

The Impact of Proteomic Investigations on the Development and Improvement of Skin Laser Therapy: A Review Article

Introduction: Different molecular approaches have contributed to finding various responses of skin to external and internal tensions such as laser irradiation and many important mediators of skin disease have been identified through these approaches. However, different essential signals of skin biomarker pathways and proteins are partially detected or completely unknown. In the present study, the impact of proteomics on the evaluation of laser therapy for the treatment of skin diseases is investigated. Methods: The keywords of "Proteomics", "Laser therapy", "Skin", and "Skin disease" were searched in Google Scholar, Scopus and PubMed search engines. After screening, 53 documents were included in the study. Results: The global assessments revealed that different proteins in different signaling pathways of skin metabolism in terms of health or illness after laser therapy are expressed differentially. The results indicated that the application of proteomics is a useful method for promoting the results of laser interventions. Conclusion: This kind of research dealt with the practical proteomics of skin diseases and skin laser therapy.

Pattern analysis of 532- and 1,064-nm picosecond-domain laser-induced immediate tissue reactions in ex vivo pigmented micropig skin

Optical pulses from picosecond lasers can be delivered to the skin as single, flat-top beams or fractionated beams using a beam splitter or microlens array (MLA). In this study, picosecond neodymium:yttrium aluminum garnet laser treatment using a single flat-top beam and an MLA-type beam at the wavelengths of 532 nm and 1,064 nm were delivered on ex vivo genotype-regulated, pigmented micropig skin. Skin specimens were obtained immediately after treatment and microscopically analyzed. Single flat-top beam treatment at a wavelength of 532 nm and a fluence of 0.05-J/cm² reduced melanin pigments in epidermal keratinocytes and melanocytes, compared to untreated controls. Additionally, 0.1 J/cm²- and 1.3 J/cm²-fluenced laser treatment at 532 nm elicited noticeable vacuolation of keratinocytes and melanocytes within all epidermal layers. Single flat-top beam picosecond laser treatment at a wavelength of 1,064 nm and a fluence of 0.18 J/cm² also reduced melanin pigments in keratinocytes and melanocytes. Treatment at 1,064-nm and fluences of 1.4 J/cm² and 2.8 J/cm² generated increasing degrees of vacuolated keratinocytes and melanocytes. Meanwhile, 532- and 1,064-nm MLA-type, picosecond laser treatment elicited fractionated zones of laser-induced micro-vacuolization in the epidermis and dermis. Therein, the sizes and degrees of tissue reactions differed according to wavelength, fluence, and distance between the microlens and skin.

Low-fluenced erbium:yttrium-aluminium-garnet laser treatment in combination with broadband light pretreatment for various pigmentation disorders in Asian patients

BACKGROUND

Low-fluenced 2940-nm erbium (Er):yttrium-aluminium-garnet (YAG) resurfacing elicits ablative photothermal tissue reactions confined to the uppermost parts of the epidermis.

OBJECTIVE

To demonstrate the efficacy and safety of low-fluenced ablative Er:YAG laser treatment in combination with broadband light (BBL) pretreatment for various pigmentation disorders.

METHODS

In total, 35 Korean patients with various pigmentation disorders were pretreated with BBL, and then, low-fluenced Er:YAG laser resurfacing was performed with a beam size of 4 mm and a fluence of 1.0-1.5 J/cm² .

RESULTS

An average of 1.1 ± 0.4 sessions of combined BBL and low-fluenced Er:YAG resurfacing treatment was delivered to the patients. Most post-Er:YAG scaling fell off spontaneously over 3-5 days, and most of the post-BBL crusting disappeared spontaneously over 5-7 days. At 2 months after final treatment, the mean global aesthetic improvement scale score for the clinical improvement of pigmentation lesions was estimated as 2.5 ± 0.8, and that for the improvement of overall skin tone, texture, and wrinkles was 2.8 ± 1.0.

CONCLUSION

Our data demonstrated that post-BBL, low-fluenced Er:YAG laser resurfacing can be used to effectively treat various pigmentation disorders in Asian patients. Further improvements in overall skin tone, texture, and wrinkles were also achieved without major side effects.

Facial microcirculatory and biomechanical skin properties after single high energy (Er):YAG laser application

OBJECTIVE

Owing to skin aging and the growing demand for skin rejuvenation, minimal invasive aesthetic treatments such as laser procedures are increasingly coming into focus. However, until now, little has been known about the objective effects of these procedures with respect to skin microcirculation or changes in skin elasticity.

STUDY DESIGN

Facial skin rejuvenation was performed on 32 volunteers using ablative Erbium: YAG laser. Skin microcirculation and skin elasticity have then been evaluated objectively.

METHODS

Microcirculation (flow, SO₂ , velocity, and rHB) has been analyzed before and directly after the laser session by using the O2C device. Skin elasticity has been evaluated by using the Cutometer device (Uf, Ua, Ur, and Ue) before and directly after the laser treatment, as well as 1 week and then 1, 3, and 6 months post treatment. Further, the outcome for the volunteers regarding their satisfactory level after laser treatment was evaluated.

RESULTS

Twenty volunteers were available for a complete follow-up. Microcirculation displayed statistically significant increase in all values to 2 mm depth. The biomechanical skin parameter of firmness of skin displayed statistically significant improvement in superficial skin layer after 6 months.

CONCLUSION

Concerning microcirculation and skin elasticity the ablative Erbium: YAG laser treatment revealed similar effects on the skin like a superficial burn injury. In contrast to the determined skin elasticity parameters, firmness of skin objectively revealed a skin tightening effect after 6 months. Along with the important epidermal effect, the suitability of ablative laser treatment for skin rejuvenation has been proved in a long-term follow-up. Lasers Surg. Med. 49:891-898, 2017. © 2017 Wiley Periodicals, Inc.

Molecular effects of fractional ablative erbium:YAG laser treatment with multiple stacked pulses on standardized human three-dimensional organotypic skin models

The molecular changes in gene expression following ablative laser treatment of skin lesions, such as atrophic scars and UV-damaged skin, are not completely understood. A standardized in vitro model of human skin, to study the effects of laser treatment on human skin, has been recently developed. Therefore, the aim of the investigation was to examine morphological and molecular changes caused by fractional ablative erbium:YAG laser treatment on an in vitro full-thickness 3D standardized organotypic model of human skin. A fractional ablative erbium:YAG laser was used to irradiate organotypic human 3D models. Laser treatments were performed at four different settings using a variety of stacked pulses with similar cumulative total energy fluence (60 J/cm²). Specimens were harvested at specified time points and real-time PCR (qRT-PCR) and microarray studies were performed. Frozen sections were examined histologically. Three days after erbium:YAG laser treatment, a significantly increased mRNA expression of matrix metalloproteinases and their inhibitors (MMP1, MMP2, MMP3, TIMP1, and TIMP2), chemokines (CXCL1, CXCL2, CXCL5, and CXCL6), and cytokines such as IL6, IL8, and IL24 could be detected. qRT-PCR studies confirmed the enhanced mRNA expression of IL6, IL8, IL24, CXCLs, and MMPs. In contrast, the mRNA expression of epidermal differentiation markers, such as keratin-associated protein 4, filaggrin, filaggrin 2, and loricrin, and antimicrobial peptides (S100A7A, S100A9, and S100A12) as well as CASP14, DSG2, IL18, and IL36β was reduced. Four different settings with similar cumulative doses have been tested (N10%, C10%, E10%, and W25%). These laser treatments resulted in different morphological changes and effects on gene regulations. Longer pulse durations (1000 μs) especially had the strongest impact on gene expression and resulted in an upregulation of genes, such as collagen-1A2, collagen-5A2, and collagen-6A2, as well as FGF2. Histologically, all treatment settings resulted in a complete regeneration of the epidermis 3 days after irradiation. Fractional ablative erbium:YAG laser treatment with a pulse stacking technique resulted in histological alterations and shifts in the expression of various genes related to epidermal differentiation, inflammation, and dermal remodeling depending on the treatment setting applied. A standardized in vitro 3D model of human skin proved to be a useful tool for exploring the effects of various laser settings both on skin morphology and gene expression during wound healing. It provides novel data on the gene expression and microscopic architecture of the exposed skin. This may enhance our understanding of laser treatment at a molecular level.

Hypo-collagenesis in photoaged skin predicts response to anti-aging cosmeceuticals

BACKGROUND

Chronic sun exposure causes photoaging, the appearance of prematurely aged skin. This phenomenon is characterized by progressive alteration of the dermal extracellular matrix, including elastin and collagen fibers. While many cosmeceuticals claim to improve the appearance of photoaged skin, data are lacking regarding their ability to induce molecular responses associated with wrinkle effacement, particularly increased collagen production.

AIMS

To conduct a meta-analysis to determine whether there was a factor(s) that could predict response to various cosmeceuticals.

PATIENTS/METHODS

Hundred subjects enrolled in five separate studies of cosmeceuticals containing: L-ascorbic acid, pentapeptide, α-lipoic acid, yeast extract, or 1% idebenone. Five groups consisting of 16-20 volunteers applied one cosmeceutical to their photodamaged forearms for several weeks. Punch biopsies were obtained pretreatment and post-treatment and analyzed for type I procollagen by ELISA.

RESULTS

Analysis of basal collagenesis reinforced the notion that hypo-collagenesis is associated with photoaging severity, independent of age or gender. Treatment outcome varied greatly among subjects, ranging from no improvement to a 7-fold increase in collagenesis. Retrospective statistical meta-analysis was conducted to determine whether age, gender, type of cosmeceutical, or evidence of hypo-collagenesis in untreated skin could predict responsiveness to cosmeceuticals. Our analysis revealed that subjects with hypo-collagenesis responded 6.4 times more often than subjects with normo-collagenesis.

DISCUSSION

Hypo-collagenesis was the only factor that influenced treatment outcome. This study therefore identifies hypo-collagenesis as the unique parameter predicting anti-aging cosmeceutical treatment outcome. These findings provide a basis for future cosmetic testing and the potential development of custom formula skin care.

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 the structural support of the ECM. Injection of dermal filler, cross-linked hyaluronic acid, into the skin of individuals over 70 years of age stimulates fibroblasts to produce type I collagen. This stimulation is associated with localized increase in mechanical forces, indicated by fibroblast elongation/spreading, and mediated by upregulation 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.

Recent Advances in Fractional Laser Resurfacing: New Paradigm in Optimal Parameters and Post-Treatment Wound Care

BACKGROUND

Laser plays an increasingly prominent role in skin rejuvenation. The advent of fractional photothermolysis revolutionizes its application. Microcolumns of skin are focally injured, leaving intervening normal skin to facilitate rapid wound healing and orderly tissue remodeling.

THE PROBLEM

Even with the popularity of fractional laser devices, we still have limited knowledge about the ideal treatment parameters and postlaser wound care.

BASIC/CLINICAL SCIENCE ADVANCES

Many clinicians believe that higher microbream energy in fractional laser devices results in better clinical outcome. Two recent studies argue against this assumption. One article demonstrates that lower fluence can induce comparable molecular changes with fewer side effects. Another study corroborates this by showing that lower-density settings produce similar clinical outcome in scar remodeling as higher-density ones, but with fewer side effects. To shed light on the optimal post-treatment wound care regimen from fractional ablative resurfacing, another paper shows that platelet-rich plasma (PRP) can reduce transepidermal water loss and skin color changes within 1 month after treatment.

CLINICAL CARE RELEVANCE

For fractional nonablative resurfacing, lower settings in fluence or density may produce similar dermal remodeling as higher settings and with a better side-effect profile. Moreover, autologous PRP appears to expedite wound healing after fractional ablative resurfacing.

CONCLUSION

Lower microbeam energy in fractional laser resurfacing produces similar molecular changes and clinical outcome with fewer side effects. The findings might portend a shift in the paradigm of treatment parameters. Autologous PRP can facilitate better wound healing, albeit modestly. Long-term follow-ups and larger studies are necessary to confirm these findings.

Direct quantitative comparison of molecular responses in photodamaged human skin to fractionated and fully ablative carbon dioxide laser resurfacing

BACKGROUND

Fractionated ablative laser resurfacing has become a widely used treatment modality. Its clinical results are often found to approach those of traditional fully ablative laser resurfacing.

OBJECTIVE

To directly compare the molecular changes that result from fractionated and fully ablative carbon dioxide (CO(2)) laser resurfacing in photodamaged human skin.

METHODS AND MATERIALS

Photodamaged skin of 34 adult volunteers was focally treated at distinct sites with a fully ablative CO(2) laser and a fractionated CO(2) laser. Serial skin samples were obtained at baseline and several time points after treatment. Real-time reverse transcriptase polymerase chain reaction technology and immunohistochemistry were used to quantify molecular responses to each type of laser treatment.

RESULTS

Fully ablative and fractionated CO(2) laser resurfacing induced significant dermal remodeling and collagen induction. After a single treatment, fractionated ablative laser resurfacing resulted in collagen induction that was approximately 40% to 50% as pronounced as that induced by fully ablative laser resurfacing.

CONCLUSIONS

The fundamental cutaneous responses that result from fully ablative and fractionated carbon dioxide laser resurfacing are similar but differ in magnitude and duration, with the fully ablative procedure inducing relatively greater changes including more pronounced collagen induction. However, the molecular data reported here provide substantial support for fractionated ablative resurfacing as an effective treatment modality for improving skin texture.

Spatial-temporal modulation of CCN proteins during wound healing in human skin in vivo

CCN proteins are important modulators of development and function of adult organs. In this study, we examined the localization and expression of the six CCN family members in normal adult human skin and during wound healing in vivo. Transcript and protein expression were studied by laser-capture microdissection-coupled real-time PCR and immunohistochemistry, respectively. Our results demonstrate that CCN1, CCN4, and CCN6 are expressed at relatively low levels in normal human skin. CCN2, CCN3, and CCN5 are the most highly expressed transcripts in the epidermis. CCN3 and CCN5 proteins are prominent in epidermal keratinocytes, whereas CCN2 is primarily expressed in melanocytes. Differential expression within epidermal layers suggests that CCN3 and CCN5 are linked with keratinocyte differentiation. CCN2, CCN3 and CCN5, are the three most highly expressed transcripts in the dermis. Their respective proteins are produced to various extents by dermal fibroblasts, blood vessels, eccrine sweat glands and hair follicles. We find that most CCN family members are temporally and specifically regulated during different phases (inflammation, proliferation, and remodeling) of partial thickness wound repair. By highlighting spatial-temporal regulations of CCN family member expression in relation to cell proliferation and differentiation, our results suggest a diverse range of functions for CCN proteins in both epidermal and dermal cells, and provides a solid reference for interpretation of future studies aimed at understanding the role of CCN proteins in human skin physiology and diseases.