Effects of 420-nm intense pulsed light in an acne animal model

5-aminolevulinic acid photodynamic therapy using 560-1200 nm followed by 420-1200 nm broadband light in the treatment of moderate-to-severe acne

BACKGROUND

Moderate-to-severe acne vulgaris, which is a chronic inflammatory skin disease, seriously impacts millions of people. However, traditional therapies may cause severe adverse reactions that are unacceptable to many patients, thus limiting the further application of these therapies. Novel therapeutic approaches to effectively treat moderate-to-severe acne vulgaris with minimal adverse reactions are urgently needed. In this retrospective study, we investigated the efficacy and adverse reactions of photodynamic therapy (PDT) using 560-1200 nm followed by 420-1200 nm broadband light (BBL).

METHODS

Twenty-four patients with moderate-to-severe acne vulgaris were included in the study and all patients expressed a strong desire for beauty. After aminolevulinic acid (ALA) gel applied, the entire face was sequentially irradiated by using BBL with a 560 nm cut-off filter (560-1200 nm), followed by BBL with a 420 nm cut-off filter (420-1200 nm). The clinical efficacy was evaluated by the proportion of patients achieving cured response and excellent response (effective rate), based on the percentage of lesions reduction (treatment rate). The fluorescent images and photographs of acne vulgaris were recorded. Pain and other common local adverse reactions during the treatment were also recorded and evaluated.

RESULTS

In patients with moderate acne, the mean treatment rates were 57.74 ± 16.40 (%) and 87.40 ± 8.521 (%) at the 6th week and 12th week of treatment, respectively. In patients with severe acne, the mean treatment rates were 60.95 ± 12.06 (%) and 85.04 ± 9.115 (%) at the 6th week and 12th week of treatment, respectively. At the 6th and 12th weeks of treatment, the effective rates of patients were 20.00 % and 93.33 % in patients with moderate acne, and 0.000 % and 88.89 % in patients with severe acne, respectively. Pain scores were significantly higher in patients with severe acne compared to patients with moderate acne when receiving 560-1200 nm BBL-PDT. Additionally, patients when receiving 420-1200 nm BBL-PDT exhibited significantly higher pain scores than those when receiving 560-1200 nm BBL-PDT. The degree of erythema was more severe in patients with severe acne than in those with moderate acne. The pigmentation was observed in one patient with moderate acne and one patient with severe acne.

CONCLUSION

The 560-1200 nm and 420-1200 nm BBL-PDT therapy can effectively treat moderate-to-severe acne vulgaris with tolerable adverse reactions, providing a new option for patients with higher esthetic requirements.

The use of light in the treatment of acne vulgaris-a review

Topical and oral antibiotic therapy is also a popular method of treatment. The effectiveness of this method is limited by the increasing resistance of bacteria to antibiotics. Over the decades since the introduction of antibiotics to treat acne, the resistance levels of bacteria have changed. This defense mechanism is developed evolutionarily. Modifications of antibiotic receptor sites, alteration of drug influx/efflux, or enzymatic degradation are common mechanisms used by bacteria to initiate and strengthen internal antibiotic resistance. The basic chromophores used in light therapy are hemoglobin, melanin, water bound to proteins, and porphyrins. Hemoglobin absorbs light mainly at 580 nm, while melanin absorbs the entire visible spectral range (400-750 nm). Porphyrins are aromatic compounds, classified as photosensitizing substances, intensively absorbing blue light, and to a lesser extent in long visible bands, such as orange and red light. Using IPL makes it possible to cover the maximum light absorption of porphyrins and hemoglobin, therefore it can be an effective tool in the treatment of inflammatory lesions in acne vulgaris. In view of the effectiveness of light therapy and its effect even on antibiotic-resistant bacteria, it is worth considering the possibility of using light therapy instead of antibiotic therapy. Due to the increasing resistance of bacteria to antimicrobials, they should be used with caution and as a last resort. The high-energy light treatment act only locally (unlike with antibiotics taken orally) and on a chromophore, such as melanin, hemoglobin, or porphyrins.

Isotretinoin plus 420 nm intense pulsed light versus isotretinoin alone for the treatment of acne vulgaris: a randomized, controlled study of efficacy, safety, and patient satisfaction in Chinese subjects

Either isotretinoin or intense pulsed light (IPL) proved to be effective to alleviate acne lesions, but the combined treatment has rarely been reported. The study aimed to evaluate the efficacy, safety, and patient satisfaction of isotretinoin and 420 nm IPL combined treatment. Forty-seven patients with facial acne with Global Evaluation Acne (GEA) graded 2-4 were randomized into study group and control group. The patients in the control group received oral isotretinoin for 8 weeks. The patients in the study group were treated with oral isotretinoin for 8 weeks, together with a biweekly 420 nm IPL treatment for 4 weeks. Topical agents included adapalene and fusidic acid. Efficacy was evaluated using digital photographies taken at baseline and week 12 by an independent dermatologist, including GEA grade, lesion count, lesion reduction percentage, and effective rate. All patients completed a questionnaire about dermatology life quality index (DLQI) and satisfaction visual analog scale (VAS) on week 12, and were followed up for another 2 months. Adverse events were recorded. The patients in the study group experienced significant reduction in GEA grade, total lesions, and inflammatory lesions on week 12, compared with the control group (p < 0.05). The patients in the study group reported lower DLQI and higher VAS satisfaction (p < 0.05) and experienced lower incidence of relapse (p < 0.05). No severe adverse event was identified in both groups. Compared with isotretinoin alone, isotretinoin and 420 nm IPL combined treatment proved to be more effective within limited treatment duration. It was well-tolerated and the patients' satisfaction was high.

Efficacy and safety of intense pulsed light in the treatment of inflammatory acne vulgaris with a novel filter

Acne vulgaris is one of the most common skin diseases affecting young people. Intense pulsed light (IPL) has become a well-recognized method in the treatment of acne vulgaris. We aim evaluate the clinical efficacy and safety of a novel IPL filter at wavelength of 400-600 nm and 800-1,200 nm in the treatment of inflammatory acne lesions. Twenty-one patients with Pillsbury I-III facial acne vulgaris between July 2017 and January 2018 were enrolled in this prospective clinical study. Five sessions of IPL treatment were administered to the subjects at 4-week interval. Final assessment was performed 1 month after the final treatment. One month posttreatment, over 75% subjects exhibited excellent or good response. Of the Pillsbury I-II patients, the effective rate reached 88.24%. The inflammatory lesions were dramatically decreased (25.23 ± 2.76 versus 14.01 ± 1.98) and statistically evident (P = .031). According to Hayashi assessment of acne severity, there was a significant improvement at follow-up visit (P = .022). Moreover, patients reported significant improvements in self-evaluation. The novel IPL filter at wavelength of 400-600 nm and 800-1,200 nm provides an effective option to treatment of inflammatory acne lesions, especially for Pillsbury I-II acne patients, with minimal reversible side effects, such as transient post-inflammatory pigmentation.

Role of MMP-2(-1306 C/T) and TIMP-2(-418G/C) Polymorphism in Chinese Han Patients with Acne Vulgaris

Acne is the most common chronic inflammatory skin diseases. Multiple factors, such as hormonal, environmental, immunological, and genetic factors, are thought to be involved in acne. However, genetic studies have yet to elucidate the full mechanism of acne. The aim of this study was to investigate the association of MMP-2 (-1306C/T) and TIMP-2 (-418G/C) polymorphisms with the risk of acne vulgaris in a Chinese Han population. We also analyzed the correlation of clinical parameters and family history in patients with acne vulgaris. This study included 251 acne patients and 121 age- and sex-matched healthy controls. Genomic DNA was extracted from peripheral blood, and genotyping was performed by PCR and DNA sequencing techniques. There is a significant correlation between the MMP-2 (-1306C/T) polymorphism and the acne vulgaris (P<0.001). Although no association was found between the TIMP-2 (-418G/C) polymorphism and the acne vulgaris, patients with the MMP-2 CT/TIMP-2 GG or GC allele are at higher risk of acne vulgaris. There is also a significant difference in the severity of the disease between acne vulgaris patients with and without family history (P<0.001). This study indicated that the MMP-2 (-1306C/T) polymorphism, in combination with the TIMP-2 (-418G/C) polymorphism, contributes to acne vulgaris susceptibility in the Chinese Han population.

Effects of Intradermal Radiofrequency Treatment and Intense Pulsed Light Therapy in an Acne-induced Rabbit Ear Model

Acne vulgaris is a common condition that can have psychologically deleterious effects. Since current treatments carry the risks of antibiotic resistance or teratogenicity, novel treatment modalities are under investigation. Our study investigated the efficacy of intradermal radiofrequency treatment (RF) and intense pulsed light (IPL) in the treatment of acne vulgaris in a rabbit ear model. We evaluated the effectiveness of IPL, RF, and a combination treatment on cultured Cuticobacterium acnes strains in an induced rabbit ear model, according to clinical outcomes as well as histological and immunological approaches. We found that RF treatment markedly decreases papule volume, while IPL appears to have an immunomodulatory effect. In combination, the two have an additive effect in treatment. These findings suggest that combination of RF and IPL may be an effective therapeutic option for the treatment of acne vulgaris.

Association of the TNF-α gene promoter polymorphisms at nucleotide -238 and -308 with acne susceptibility: a meta-analysis

BACKGROUND

The tumour necrosis factor (TNF)-α -238 and -308 polymorphisms are potential candidate genes that may serve as modulators in susceptibility to acne.

AIM

We performed a meta-analysis of case-control studies to assess the association of the TNF-α -238 and -308 polymorphisms with acne susceptibility.

METHODS

The PubMed, EMBASE, Scopus, SinoMed and China National Knowledge Infrastructure databases were systematically searched to identify eligible studies. OR and 95% CI were calculated to evaluate the association.

RESULTS

We identified seven independent case-control studies up to September 2017. The results revealed an association between the A allele of the TNF-α -238 polymorphism and increased susceptibility to acne in Asian (OR = 1.61, 95% CI 1.08-2.40) but not in European (OR = 1.10, 95% CI 0.63-1.93) populations. For the TNF-α -308 polymorphism, the minor A allele was associated with increased acne susceptibility in Asian (OR = 1.93, 95% CI 1.15-3.24) and Turkish (OR = 4.14, 95% CI 2.25-7.61) populations, but not in European (OR = 1.17, 95% CI 0.66-2.06) or Arab (OR = 0.88, 95% CI 0.64-1.22) populations. Egger test found no evidence of publication bias.

CONCLUSION

Our findings suggest that the TNF-α -238 A allele is associated with increased susceptibility to acne in Asian but not in European populations, while the TNF-α -308 A allele is associated with increased susceptibility to acne in Asian and Turkish populations but not in European or Arab populations.

Determining the optimal parameters of 420-nm intense pulsed light on Trichophyton rubrum growth in vitro

The effect of and the optimal parameters for intense pulsed light (IPL) with a 420-nm filter on an isolate of the fungus Trichophyton rubrum (T. rubrum) were examined in vitro. Colonies of T. rubrum were irradiated by using 420-nm IPL with various pulse numbers and energies. Colony areas were photographed and compared with those of untreated colonies to assess growth inhibition. Statistically significant inhibition of T. rubrum growth was detected in colonies treated with 12 pulses of greater than or equal to 12 J/cm². The optimal parameters of 420-nm IPL were 12 pulses of 12 J/cm². However, more in vitro and in vivo studies are necessary to investigate and explore this mechanism to determine whether IPL would have a potential use in the treatment of fungal infections of the skin.

The Role of NADPH Oxidase in the Inhibition of Trichophyton rubrum by 420-nm Intense Pulsed Light

Objectives: To evaluate the effect of intense pulsed light (IPL) on Trichophyton rubrum and investigate its mechanism of action.

Methods: The viability of fungi treated with IPL alone and with IPL combined with an NADPH oxidase inhibitor (DPI) pretreatment was determined by MTT assays. The reactive oxygen species (ROS) were quantified with a DCFH-DA fluorescent probe. Malondialdehyde (MDA) content and superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities were determined by commercial kits. The transcription of the Nox gene was quantified using quantitative real-time PCR (qRT-PCR) analysis, and micromorphology was observed using scanning electron microscopy (SEM). In addition, fungal keratinase activity was detected by measuring dye release from keratin azure.

Results: The growth declined with statistical significance after 6 h of treatment (P < 0.001). The ROS and MDA content increased after IPL treatment, whereas the SOD and GSH-Px activity decreased. Nox gene expression was upregulated, and the micromorphology was damaged. Keratinase activity decreased. Fungi that received DPI pretreatment exhibited contrasting outcomes.

Conclusion: We found that 420-nm IPL significantly inhibited the growth and pathogenicity of T. rubrum in vitro. A suggested mechanism involves Nox as a factor that mediates 420-nm IPL-induced oxidative damage of T. rubrum.

Antimicrobial and anti-inflammatory activity of chitosan-alginate nanoparticles: a targeted therapy for cutaneous pathogens

Advances in nanotechnology have demonstrated potential application of nanoparticles (NPs) for effective and targeted drug delivery. Here we investigated the antimicrobial and immunological properties and the feasibility of using NPs to deliver antimicrobial agents to treat a cutaneous pathogen. NPs synthesized with chitosan and alginate demonstrated a direct antimicrobial activity in vitro against Propionibacterium acnes, the bacterium linked to the pathogenesis of acne. By electron microscopy (EM) imaging, chitosan-alginate NPs were found to induce the disruption of the P. acnes cell membrane, providing a mechanism for the bactericidal effect. The chitosan-alginate NPs also exhibited anti-inflammatory properties as they inhibited P. acnes-induced inflammatory cytokine production in human monocytes and keratinocytes. Furthermore, benzoyl peroxide (BP), a commonly used antiacne drug, was effectively encapsulated in the chitosan-alginate NPs and demonstrated superior antimicrobial activity against P. acnes compared with BP alone while demonstrating less toxicity to eukaryotic cells. Together, these data suggest the potential utility of topical delivery of chitosan-alginate NP-encapsulated drug therapy for the treatment of dermatologic conditions with infectious and inflammatory components.

Killing bacterial spores with blue light: when innate resistance meets the power of light

This article is a highlight of the study by Maclean et al. in this issue of Photochemistry and Photobiology describing the sporicidal effects 405 nm visible light alone on endospores of the Clostridium and Bacillus genera. 1.73 kJ cm(-2) was capable of reducing endospore colony-forming units by up to 4-log(10). These findings have never been previously demonstrated and may be incorporated into decontamination methods that span medical, military and food preparatory applications.

Blue light for infectious diseases: Propionibacterium acnes, Helicobacter pylori, and beyond?

Blue light, particularly in the wavelength range of 405-470 nm, has attracted increasing attention due to its intrinsic antimicrobial effect without the addition of exogenous photosensitizers. In addition, it is commonly accepted that blue light is much less detrimental to mammalian cells than ultraviolet irradiation, which is another light-based antimicrobial approach being investigated. In this review, we discussed the blue light sensing systems in microbial cells, antimicrobial efficacy of blue light, the mechanism of antimicrobial effect of blue light, the effects of blue light on mammalian cells, and the effects of blue light on wound healing. It has been reported that blue light can regulate multi-cellular behavior involving cell-to-cell communication via blue light receptors in bacteria, and inhibit biofilm formation and subsequently potentiate light inactivation. At higher radiant exposures, blue light exhibits a broad-spectrum antimicrobial effect against both Gram-positive and Gram-negative bacteria. Blue light therapy is a clinically accepted approach for Propionibacterium acnes infections. Clinical trials have also been conducted to investigate the use of blue light for Helicobacter pylori stomach infections and have shown promising results. Studies on blue light inactivation of important wound pathogenic bacteria, including Staphylococcus aureus and Pseudomonas aeruginosa have also been reported. The mechanism of blue light inactivation of P. acnes, H. pylori, and some oral bacteria is proved to be the photo-excitation of intracellular porphyrins and the subsequent production of cytotoxic reactive oxygen species. Although it may be the case that the mechanism of blue light inactivation of wound pathogens (e.g., S. aureus, P. aeruginosa) is the same as that of P. acnes, this hypothesis has not been rigorously tested. Limited and discordant results have been reported regarding the effects of blue light on mammalian cells and wound healing. Under certain wavelengths and radiant exposures, blue light may cause cell dysfunction by the photo-excitation of blue light sensitizing chromophores, including flavins and cytochromes, within mitochondria or/and peroxisomes. Further studies should be performed to optimize the optical parameters (e.g., wavelength, radiant exposure) to ensure effective and safe blue light therapies for infectious disease. In addition, studies are also needed to verify the lack of development of microbial resistance to blue light.