Skin characteristics after fractional photothermolysis

Quantitative simulation of photothermal effect in laser therapy of hypertrophic scar

BACKGROUND

Laser technology has been widely used in the treatment of hypertrophic scar (HPS). Due to the lack of effective quantitative relationship between laser doses and thermal effect of lesion tissue, the selection of laser doses in clinical laser treatment of HPS is blind, which cannot guarantee the best treatment effect.

MATERIALS AND METHODS

The photothermal model of HPS was established by using finite element method. The effects of laser dose parameters such as laser energy density, pulse width, and spot diameter on the thermal effects of laser treatment were analyzed. According to tissue temperature threshold and thermal damage degree of the simulation results, the optimal laser doses of HPS were selected for the laser treatment experiments of rabbit ear HPSs to verify the rationality of the quantitative photothermal model.

RESULTS

The temperature rise and thermal damage degree of HPS following laser treatment were directly correlated to the laser doses, which grew with the increase of energy density and laser pulse width. For the different spot diameters, the temperature rise decreased with the increase of spot diameter, whereas the thermal damage degree worsened with the increase of spot diameter. Both simulation and experimental results show that the optimal treatment parameters of HPS were as follows: The laser energy density was 7.5 J/cm3 , the pulse width was 4 ms, and the spot diameter was 7 mm.

CONCLUSION

The laser dose parameters optimized by the photothermal model have achieved good therapeutic effects in the rabbit ear HPS, indicating that the model can be used for quantitative evaluation of laser doses before clinical treatment.

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.

Adverse Events of Nonablative Lasers and Energy-Based Therapies in Subjects with Fitzpatrick Skin Phototypes IV to VI: A Systematic Review and Meta-Analysis

BACKGROUND

Although there is an abundance of literature on nonablative laser and energy-based therapies for the management of skin conditions, adverse events are inconsistently addressed and range widely across studies. Fitzpatrick skin phototypes (SPTs) IV to VI are believed to be at higher risk.

OBJECTIVES

The aim of this study was to determine the types and rates of adverse events in nonablative laser and energy-based therapies among patients with SPTs IV to VI.

METHODS

Articles addressing nonablative laser and energy-based therapies for skin rejuvenation and acne scarring in patients with SPTs IV to VI that provided data on adverse events were included. The pooled prevalence of each adverse event was calculated. To determine whether age, treatment indication, SPT, and device type influenced incidence, subgroup and meta-regression analyses were performed. Heterogeneity was evaluated with the I2 statistic.

RESULTS

Forty-three studies were included in the meta-analysis. The sample size was 1654, and the median age of subjects was 39.4 years. The most common adverse events were postinflammatory hyperpigmentation (PIH) (rate, 8.1%) and prolonged erythema (rate, 0.6%). The rate of PIH was significantly higher for diode and erbium-doped lasers compared with intense pulsed light and radiofrequency. PIH correlated positively with SPT, laser density, and total energy delivered.

CONCLUSIONS

Although the overall rate of adverse events in nonablative laser and energy-based therapies for SPTs IV to VI is low, the incidence of PIH is not insignificant. Certain lasers, such as diode, Q-switched Nd:YAG, and erbium-doped lasers, tend to have higher rates of PIH, whereas intense pulsed light and radiofrequency have minimal risk. Higher SPTs and higher energy deliverance correlate positively with the incidence of PIH.

LEVEL OF EVIDENCE: 4

Skin Wound Tension Reduction Device Combined with Ablative Fractional Carbon Dioxide Laser to Reduce Scar Formation After Excision of Pediatric Facial Skin Lesions: A Prospective Cohort Study

Purpose

To investigate the efficacy of skin wound tension reduction device (SWTRD) combined with ablative fractional carbon dioxide laser (CO2-AFL) for the prevention of scar formation following the excision of facial cutaneous lesions in children.

Methods

Patients undergoing surgical excision of facial cutaneous lesions in our hospital between May 2019 and April 2021 were enrolled. After the excision of facial cutaneous lesions and based on the personal intents and conditions, patients were assigned to undergo SWTRD combined with CO2-AFL. Outcome evaluations were as follows: defect size, incision width, scar width, the Vancouver Scar Scale (VSS) and University of North Carolina 4P Scar Scale (UNC4P).

Results

A total of 25 pediatric patients (mean age, 9.88 years) were enrolled in the study. Following the treatment of SWTRD+CO2-AFL, scar widths were relatively narrow and the appearance of the incision scars was significantly improved. A significant reduction in the patient-reported UNC4P scores at 6 months (3, 1–4) was observed when compared with that at 2 months (0, 0–1) after surgery (p<0.001). A similar reduction in the VSS scar scale was also evident (6 months: 1, 0.75–2.5 vs 2 months: 6.5–8.5; p<0.001).

Conclusion

Combined SWTRD and CO2-AFL treatment effectively modulates the scar formation after the incision is healed and resulting in preventing scar widening, leading to the improvement of scar appearance, reduction in wound pain and pruritus and its overall prognosis.

Study of a 532/1064 Fractional Picosecond Laser for Facial Rejuvenation

BACKGROUND AND OBJECTIVES

Picosecond (ps) fractional lasers create small wounds, presumably by laser-induced optical breakdown. We studied a ps fractional laser in the treatment of wrinkles and mottled pigment.

MATERIALS AND METHODS

This was a single center, prospective, open-label clinical trial. Patients with at least 2 facial areas, with visible wrinkles and dyschromia, were enrolled in the study and received 3 treatments at monthly intervals and appeared at 3 follow-up visits at 1, 3, and 6 months after treatment. The laser is an 800 ps fractional system with nominal 10 mm macrospot diameter. Both 532 nm and 1,064 nm wavelengths were applied in each subject. Wrinkle and pigmentation clearance were assessed by 2 blinded investigators using a 5-point clearance scale. Skin improvement was assessed by investigators using the 5-point Global Aesthetic Improvement (GAI) Scale based on before/after photographs for the following categories: (1) fine lines/wrinkles and (2) pigmentation.

RESULTS

A total of 18 healthy subjects at a single site were enrolled. At least moderate pigmentation and fine line/wrinkles improvement were observed in 93% and 79% of patients at 1 month after the last treatment according to GAI, respectively. Pigment clearance approached a mean of approximately 40%.

CONCLUSION

A ps 1,064/532 fractional laser achieves reduction in fine lines and pigment.

Evolution of compressive mechanical properties of early hypertrophic scar during laser treatment

Laser therapy has been widely used in the treatment of hypertrophic scars (HPS), but whether the mechanical properties of HPS tissue after laser treatment can be restored to those of normal skin remains unclear. In this paper, the relationship between the evolution of compressive mechanical properties and histological changes of HPS tissues following three successive combined pulsed dye laser (PDL) and fractional CO₂ laser (CO₂) treatments was investigated by compression tests and histological analysis. The early HPS model of rabbit ear was established by CO₂ laser ablation. The loading-unloading tests and strain creep tests under the compression forces of 1 N, 2 N, and 3 N were carried out for normal skin, untreated HPS and HPS after different treatment times, respectively. The results showed that the compression ratio λ of all tissues revealed force dependence and rose with the increasing compression force, which was similar to the trend of most biological soft tissues. The histological changes of HPSs following laser treatment have a significant influence on the compressive mechanical response. Compared with the normal skin, the toughness and anti-deformation ability of HPS reduced due to the proliferation of collagen fibers and the destruction of elastic fibers, resulting in higher energy dissipation, compression ratio λ, and stable creep rate D, and lower elastic modulus. After three successive combined PDL/ CO₂ laser treatments, the compressive mechanical properties and creep properties of HPS gradually approached that of the normal skin owing to the gradual restoration of the amount and distribution of collagen and elastic fibers in HPS. The results provide a new method for evaluating the clinical efficacy of laser therapy for treatment of HPS tissue.

Ablative fractional CO2 laser surgery improving sleep quality, pain and pruritus in adult hypertrophic scar patients: a prospective cohort study

Background

Poor sleep quality is associated with a decrease in quality of life in patients with major burn scars, combined with pruritus and pain. Few interventions have been reported to improve the sleep quality of patients with scars. In the current prospective cohort study, we investigated the efficacy of CO₂-ablative fractional laser (AFL) surgery vs conventional surgery in post-burn patients with hypertrophic scars with sleep quality as the primary study outcome.

Methods

In total 68 consecutive patients undergoing scar surgical treatment were recruited, including a CO₂-AFL surgery cohort (n = 35) and a conventional surgery cohort (n = 33). A subgroup from the AFL cohort was selected. Sleep quality, pain and pruritus were evaluated. Multiple linear regression analyses were performed to reveal the effect of CO₂-AFL surgery.

Results

The CO₂-AFL surgery cohort had significantly lower Pittsburgh sleep quality index (PSQI) global scores than the conventional surgery cohort after the last surgical treatment. In the subgroup of patients receiving hardware sleep monitoring, CO₂-AFL markedly increased deep sleep time, deep sleep efficiency and reduced initial sleep latency. Compared to the conventional surgery cohort, the CO₂-AFL cohort presented significantly lower pain and pruritus scores. Correlation analysis showed pain and pruritus were significantly associated with PSQI scores, and there were also significant correlations between pain and pruritus scores. Multiple linear regression analysis showed that surgery method was negatively linearly correlated with visual analog scale (VAS) pain score, brief pain inventory (BPI) total, VAS pruritus score, 5-D itch scale total, four-item itch questionnaire (FIIQ) total and PSQI total.

Conclusions

CO₂-AFL surgery significantly improved sleep quality and reduced pain and pruritus of hypertrophic scar patients. The alleviation of sleep disorder was associated with improvement of deep sleep quality including deep sleep time and deep sleep deficiency.

Trial registration

The Chinese Clinical Trial Registry (ChiCTR200035268) approved retrospectively registration on 5 Aug 2020.

[Effect of CO₂ fractional laser on the early control of scar post-secondary repair in patients with a cleft lip]

OBJECTIVE

To observe and compare the clinical efficacy of CO₂ fractional laser in the early control of scar post-secondary repair in patients with a cleft lip.

METHODS

In the treatment group, 43 patients with secondary repair of cleft lip were treated via CO₂ fractional laser. The control group covered 70 patients post-cheiloplasty. The effect in the two groups after six months was compared. The duration from the beginning of the laser treatment to surgery and patient gender were analyzed to determine if they affected the efficacy of the laser treatment for scars.

RESULTS

1) The curative effect in the treatment group was better than that in the control group (P<0.000 1), the total effectiveness rate was 90.7% in the treatment group. 2) No significant statistical difference in efficacy was observed between men and women (P=0.487). Moreover, no significant statistical difference in efficacy (P=0.055) was observed among patients one year after surgery, within the duration of <3 months, and within the duration of ≥3 months.

CONCLUSIONS

CO₂ fractional laser had a definite effect on the treatment of scar post-secondary repair in patients with a cleft lip. No significant correlation was observed between treatment effect and patient gender, and no difference was noted among patients one year after surgery. In the beginning of the laser treatment, no difference was observed between the durations of <3 months and ≥3 months after the reconstruction, Therefore, early intervention of scars a year after secondary repair of a cleft lip can achieve good results.

Before-after cohort study to assess the efficacy of fractional ablative carbon dioxide laser treatment of pediatric hand scars

The purpose of this study is to investigate the efficacy of fractional ablative carbon dioxide laser (AFXL) surgery in patients with pediatric hand scars. This study enrolled hand scar patients who received treatment in our hospital between May 2018 and April 2019. Patients were assigned to undergo AFXL surgery based on their personal intents and condition, whereas the fractional laser was used for stiffness and abnormal texture. Outcomes were as follows: hand function was evaluated using the Michigan hand outcomes questionnaire; scar condition was evaluated using the Vancouver scar scale and UNC4P scar scale. Total 30 pediatric patients (mean age, 11.4 years) were eligible for the study and laser-treated scars were significantly improved in Michigan hand outcomes questionnaire from 52.30 ± 6.14 to 66.91 ± 6.43 (p < 0.001). Provider-rated Vancouver scar scale dropped from 8.80 ± 2.75 to 6.73 ± 2.52 (p < 0.001). Patient-reported UNC4P scar scale declined from7.07 ± 2.02 to 4.73 ± 1.31 (p < 0.001). AFXL surgery can significantly improve hand function and appearance of pediatric hand scars, suggesting its advantages over traditional methods of operative intervention.

Laser management of hypertrophic burn scars: a comprehensive review

Hypertrophic scars often develop following burn-related injuries. These scars can be cosmetically unappealing, but associated symptoms of pruritus, pain and restricted range of motion can impair a person’s quality of life. Laser and light therapies offer a minimally invasive, low-risk approach to treatment, with a short postoperative recovery period. As laser technology developed, studies have shown decreased scar thickness, neuropathic pain and need for surgical excision, as well as improved scar pigmentation, erythema, pliability, texture, height and pruritus. In this review, we present the evolution of laser therapy for hypertrophic burn scars, how different types of lasers work, indications, perioperative considerations and guidelines for practice management.

Evaluation of autologous adipose-derived stem cells vs. fractional carbon dioxide laser in the treatment of post acne scars: a split-face study

BACKGROUND

Scarring is a distressing outcome of acne, as it causes cosmetic and psychological problems to the patients. Unfortunately no single treatment is satisfactory; instead, employing multiple modalities may have better outcome. Autologous adipose tissue-derived adult stem cells (AT-ASCs) and their secretory factors can stimulate collagen synthesis; angiogenesis and migration of fibroblasts thus regenerate damaged tissues. Also, conventional treatments for acne scarring, such as lasers and topical regimens, induce new collagen synthesis via activation of dermal fibroblasts or growth factors. The aim of the study was to verify the effectiveness of AT-ASCs for the treatment of acne scarring vs. the fractional carbon dioxide laser (FxCR).

SUBJECTS AND METHODS

Split face comparative study included 10 adult patients with post-acne scars on both sides of the face. One side received AT-ASCs single injection while the other received three sessions of FxCR. Scars were then assessed using the global scoring system Goodman and Baron, scar area percent using NIH ImageJ software and functional assessment by measuring the transepidermal water loss (TEWL) and skin hydration. Both sides were followed for three months.

RESULTS

A significant improvement in the degree of scar severity, scar area percent, skin hydration, and TEWL after 3 months of treatment on both sides of the face with insignificant differences between both treatment modalities, provided that AT-ASCs treatment was employed once vs. three sessions of FxCR.

CONCLUSION

One injection of AT-ASCs is as effective as three sessions of FxCR in the treatment of atrophic acne scars.

Comparison of Fractional CO2 Laser, Verapamil, and Triamcinolone for the Treatment of Keloid

Objective: Scar biology is a territory less understood. The search for ideal treatment of keloid continues. The aim of this study was to compare the role of CO₂ laser, triamcinolone (TAC), and verapamil in the treatment of keloid. Approach: A randomized parallel-group study was conducted in which 60 patients were randomly allocated to three groups from May 2017 to April 2018. First group received fractional CO₂ laser therapy, second group received triamcinolone, and third group received intralesional verapamil. Outcomes were evaluated using Vancouver scar scale score at 3 weekly intervals for 6 months. Results: There was a reduction in scar height, vascularity, and pliability in all the three groups. However, pigmentation was not completely resolved by any of the three modalities. The response was fastest in case of triamcinolone followed by verapamil and laser, which was statistically significant. There was reduction in pain and pruritus in all the three groups and lesser injection site pain with verapamil. There was some amount of charring with CO₂ laser. Innovation: Our study provides evidence that TAC has the fastest response in treating keloids when compared to other modalities. Scar pigmentation is the parameter that is not completely resolved by TAC, verapamil, or CO₂ laser. Conclusion: The study revealed that fractional CO₂ laser and verapamil are as efficient as triamcinolone acetonide (TAC) for treating keloids, except it takes longer for laser and verapamil to act compared to TAC. Verapamil can be used as an alternative treatment modality that is cost-effective with minimal adverse effects.

Adipose Stem Cells with Conditioned Media for Treatment of Acne Vulgaris Scar

This study was to investigate the effect of subcutaneous injection of the adipose stem cells (ASCs) with conditioned media (CM) in the treatment of acne vulgaris scar. We used Adult male New Zealand white rabbit ears as an animal model and induced acne formation by Kignman method. Adipose tissue was isolated and harvested from the scapula of rabbits, and ASCs were cultured and expanded until passage 1. There have four groups in our experiment, include phosphate buffered saline (PBS), ASCs with PBS (ASC + PBS), CM, and ASCs with CM (ASC + CM) group. This solution of 0.6 ml injected to subcutaneous in each group. ASC + PBS and ASC + CM groups were containing ASCs of 5.0 × 106 cells/ml. We analyzed the treatment of 4 groups to scar tissue after 2 and 4 weeks by hematoxylin and eosin stain, immunohistochemistry, and RNA expression level of tumor necrosis factor-α (TNF-α), interleukin-1α (IL-1α), and matrix metalloproteinase-2 (MMP-2). Also, the expression of keratin 16 (K16) was detected by western blot analysis. H&E stain showed that infiltration of inflammation cells was significantly reduced at 2 and 4 weeks, as well as re-epithelialization was improved in the ASC + CM group. The ASC + CM gourp was reduced both expression levels of TNF-α, IL-1α, and MMP-2 and K16 protein level. In conclusion, the ASCs with CM has a significant curative effect on acne vulgaris scar, more to the point, the CM has a key role on treatment. It could be applied to a therapeutic approach to regenerate to treat acne vulgaris scar.

The Efficacy and Safety of Fractional CO₂ Laser Combined with Topical Type A Botulinum Toxin for Facial Rejuvenation: A Randomized Controlled Split-Face Study

Objective. We evaluated synergistic efficacy and safety of combined topical application of Botulinum Toxin Type A (BTX-A) with fractional CO₂ laser for facial rejuvenation. Methods. Twenty female subjects were included for this split-face comparative study. One side of each subject's cheek was treated with fractional CO₂ plus saline solution, and the other side was treated with fractional CO₂ laser plus topical application of BTX-A. Patients received one session of treatment and evaluations were done at baseline, one, four, and twelve weeks after treatment. The outcome assessments included subjective satisfaction scale; blinded clinical assessment; and the biophysical parameters of roughness, elasticity, skin hydration, transepidermal water loss (TEWL), and the erythema and melanin index. Results. BTX-A combined with fractional CO₂ laser sides showed higher physician's global assessment score, subject satisfaction score, roughness, skin hydration, and skin elasticity compared to that of fractional CO₂ plus saline solution side at 12 weeks after treatment. TEWL and erythema and melanin index showed no significant differences between two sides at baseline, one, four, and twelve weeks after treatment. Conclusion. Topical application of BTX-A could enhance the rejuvenation effect of fractional CO₂ laser.

The efficacy of conditioned media of adipose-derived stem cells combined with ablative carbon dioxide fractional resurfacing for atrophic acne scars and skin rejuvenation

OBJECTIVE

To evaluate the effects of conditioned medium of adipose-derived stem cells (ADSC-CM) on efficacy and side effects after fractional carbon dioxide laser resurfacing (FxCR) when treating subjects with facial atrophic acne scars or with skin rejuvenation needs.

MATERIALS AND METHODS

Twenty-two subjects were enrolled in the study and divided into two groups. Nine subjects were included in skin rejuvenation group and thirteen subjects were included in acne scar group, and all subjects underwent three sessions of FxCR. ADSC-CM was applied on FxCR site of one randomly selected face side. Evaluations were done at baseline, 1 week after first treatment, and 1 month after each treatment. The outcome assessments included subjective satisfaction scale; blinded clinical assessment; and the biophysical parameters of roughness, elasticity, skin hydration, transepidermal water loss (TEWL), and the erythema and melanin index. Biopsies taken from one subject in skin rejuvenation group were analyzed using hematoxylin and eosin, Masson's Trichrome, and Gomori's aldehyde fuchsin staining.

RESULTS

ADSC-CM combined with FxCR increased subject satisfaction, elasticity, skin hydration, and skin elasticity and decreased TEWL, roughness, and the melanin index in both acne scars and skin rejuvenation groups. Histologic analysis showed that ADSC-CM increased dermal collagen density, elastin density, and arranged them in order.

CONCLUSION

ADSC-CM with FxCR is a good combination therapy for treating atrophic acne scars and skin rejuvenation.

TRIAL REGISTRATION

JSPH2012-082 - Registered 14 Feb 2012.

Fractional Erbium laser in the treatment of photoaging: randomized comparative, clinical and histopathological study of ablative (2940nm) vs. non-ablative (1540nm) methods after 3 months

BACKGROUND

Fractional non-ablative lasers keep the epidermis intact, while fractional ablative lasers remove it, making them theoretically more effective.

OBJECTIVES

To evaluate the clinical and histological alterations induced by fractional photothermolysis for treating photoaging, comparing the possible equivalence of multiple sessions of 1540nm Erbium, to one session of 2940nm Erbium.

METHODS

Eighteen patients (mean age 55.9) completed the treatment with three sessions of 1540nm fractional Erbium laser on one side of the face (50 mJ/mB, 15ms, 2 passes), and one session of 2940nm on the other side (5mJ/mB, 0.25ms, 2 passes). Biopsies were performed before and 3 months after treatment. Clinical, histological and morphometric evaluations were carried out.

RESULTS

All patients presented clinical improvement with no statistically significant difference (p> 0.05) between the treated sides. Histopathology revealed a new organization of collagen and elastic fibers, accompanied by edema, which was more evident with the 2940nm laser. This finding was confirmed by morphometry, which showed a decrease in collagen density for both treatments, with a statistical significance for the 2940nm laser (p > 0.001).

CONCLUSIONS

Three 1540nm sessions were clinically equivalent to one 2940nm session. The edema probably contributed to the positive results after three months, togheter with the new collagen and elastic fibers organization. The greater edema after the 2940nm session indicates that dermal remodeling takes longer than with 1540nm. It is possible that this histological superiority relates to a more prolonged effect, but a cohort longer than three months is needed to confirm that supposition.

Comparison study of fractional carbon dioxide laser resurfacing using different fluences and densities for acne scars in Asians: a randomized split-face trial

BACKGROUND

Ablative 10,600-nm carbon dioxide (CO2 ) fractional laser treatments have shown favorable outcomes for atrophic acne scars.

OBJECTIVE

To compare the efficacy and complications of fractional CO2 laser treatments with different fluences and densities for acne scars.

METHODS

Twenty patients were treated using a single session of fractional CO2 laser in Deep FX mode. In Group A (n = 10), half of the face was treated with 20 mJ, density 10% and the other half with 20 mJ, density 20%. In Group B (n = 10), half of the face was treated with 10 mJ, density 10% and the other half with 20 mJ, density 10%. Patients were evaluated at baseline and 3 days, 1 week, 1 month, and 3 months after the procedure.

RESULTS

There was no significant difference in efficacy between different laser settings within the groups, although adverse effects were more evident in patients treated with higher densities or fluences.

CONCLUSION

Factional CO2 laser treatment using the Deep FX mode may provide a significant efficacy with lower fluence and density with fewer complications than with higher energies for acne scars.

The effect of conditioned media of adipose-derived stem cells on wound healing after ablative fractional carbon dioxide laser resurfacing

Objective. To evaluate the benefits of conditioned medium of Adipose-derived stem cells (ADSC-CM) on wound healing after fractional carbon dioxide laser resurfacing (FxCR) on human skin. Materials and Methods. Nineteen subjects were treated with FxCR on the bilateral inner arms. ADSC-CM was applied on FxCR site of one randomly selected arm. Transepidermal water loss (TEWL), skin color, and gross-elasticity of FxCR site on both arms were measured. Skin samples were taken by biopsy from three subjects 3 weeks after treatment for histopathological manifestations and mRNA expressions of procollagen types I and III, elastin genes were noted. Results. The index of erythema, melanin, and TEWL of the ADSC-CM-treated skin were significantly lower than those of the control side. The mRNA expression of type III procollagen in ADSC-CM-treated group at 3 weeks posttreatment was 2.6 times of that of the control group. Conclusion. Application of allograft ADSC-CM is an effective method for enhancing wound healing after FxCR, by reducing transient adverse effects such as erythema, hyperpigmentation, and increased TEWL.