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

Photodynamic Inactivation Mediated by Endogenous Porphyrins of Corynebacterium diphtheriae in Planktonic and Biofilm Forms

Photodynamic inactivation (PDI) has emerged as a promising approach to combat bacterial infections by using light activation of photosensitizers to induce microbial death. This study investigated the potential of endogenous porphyrins produced by Corynebacterium diphtheriae as photosensitizers for PDI. Qualitative analysis revealed the presence of porphyrins in all strains studied, with coproporphyrin III predominating. The addition of 5-aminolevulinic acid (ALA) enhanced porphyrin production, as evidenced by increased fluorescence intensity. In addition, high-performance liquid chromatography with diode array and mass spectrometry detection analyses confirmed the presence of coproporphyrin III and protoporphyrin IX in all strains, and the ALA supplementation did not alter the porphyrin profiles. Quantitative analysis showed that strain-dependent coproporphyrin III levels were significantly increased with ALA supplementation. Additionally, biofilm formation was positively correlated with porphyrin production, suggesting a role for porphyrins in biofilm formation. Photoinactivation experiments showed that the strains responded differently to light exposure, with ALA supplementation, reducing the time required for significant CFU/mL reduction. In addition, biofilm survival exceeded planktonic cell survival, highlighting the challenges posed by biofilm structures with regard to PDI efficacy. Despite the variable responses observed, all strains exhibited a reduction in viability following light exposure, demonstrating the potential of endogenous porphyrins for antimicrobial photoinactivation applications.

Red and blue LED light increases the survival rate of random skin flaps in rats after MRSA infection

Skin flap transplantation is a conventional wound repair method in plastic and reconstructive surgery, but infection and ischemia are common complications. Photobiomodulation (PBM) therapy has shown promise for various medical problems, including wound repair processes, due to its capability to accelerate angiogenesis and relieve inflammation. This study investigated the effect of red and blue light on the survival of random skin flaps in methicillin-resistant Staphylococcus aureus (MRSA)-infected Sprague Dawley (SD) rats. Forty male SD rats were divided into control and light-emitting diode-red and blue light-treated (LED-RBL) groups at a ratio of 1:1 and a McFarland flap procedure was performed, which was subsequently infected with MRSA strains. After 7 days, the appearance and survival of the flaps were evaluated. The microvascular density was determined by hematoxylin and eosin (HE) staining. The expression levels of vascular endothelial growth factor (VEGF), hypoxia inducible factor 1α (HIF-1α), phosphatidylinositol 3-kinase (PI3K), and protein kinase B (normally expressed as AKT) were detected by immunohistochemistry. The flap survival rate and microvascular density in the LED-RBL group were significantly higher than those in the control group (P < 0.05). In addition, the VEGF, HIF1-α, PI3K, and AKT levels were significantly higher in the LED-RBL group compared to the control group (P < 0.05). Red and blue light increased the survival area of the infected flap in rats by promoting angiogenesis, relieving oxidative stress, and reducing bacterial loads, indicating that PBM therapy is a convenient, simple, analgesic, and safe treatment intervention in promoting the survival rate of transplanted flaps after wound repair surgery.

Intense Pulsed Light (IPL) for the treatment of vascular and pigmented lesions

BACKGROUND

IPL devices emit a wide range of wavelengths that can be absorbed by different chromophores in the skin. Selective destruction of a specific chromophore with minimal side effects is controlled by wavelength, pulse duration, and fluence.

AIM

This study aims to evaluate the treatment of vascular and pigmented lesions using narrow-band Intense Pulsed Light (IPL) with Advanced Fluorescence Technology (AFT), which offers more efficient energy usage per pulse to increase safety, and improve clinical outcomes.

METHODS

A retrospective analysis of data from 100 patients treated with narrow-band IPL for vascular and pigmented lesions. Efficacy was measured by the Global Aesthetic Improvement Scale (GAIS) and Patient Satisfaction Scale (0-10). Safety was assessed by evaluating pain levels and adverse events.

RESULTS

Mean GAIS scores were 8.02 ± 0.84 for vascular and 8.14 ± 0.9 for pigmented lesions with no significant difference between groups (p=0.49, α=0.05). Patient satisfaction correlated with GAIS scores (correlation coefficient 0.8). No pain was reported and two patients experienced temporary and transient side effects.

CONCLUSION

Overall, the advanced IPL treatments provided favorable outcomes for vascular and pigmented lesions.

The assessment of moderate acne vulgaris face skin using blood perfusion and hyperspectral imaging-A pilot study

BACKGROUND

Microcirculation is the flow of blood through the smallest vessels in the circulatory system. Capillaries respond to various pathologies much earlier than arteries and veins, the changes which indicate that the disease is already developing. Careful monitoring of the functioning of the capillary system often allows the detection of in vivo disorders at an early stage.

AIMS

The aim of the study was to evaluate the microcirculation within acne lesions. A noninvasive method of semi-quantitative blood perfusion measurement based on laser speckle contrast analysis (LASCA) and a quantitative assessment of the acne severity using the hyperspectral imaging method supported by image analysis and processing methods were used.

PATIENTS/METHOD

The acne lesion perfusion was compared to the healthy skin perfusion of the control group. The reflectance in the range from 400 to 1000 nm was also compared for acne lesions and healthy skin. A dedicated version of the algorithm based on the gray-level co-occurrence matrix was used to compare differences between acne lesions and healthy skin.

RESULTS

Blood perfusion in acne lesions is on average 117% higher than in healthy skin. The reflectance of acne lesions was lower in the range of 400-600 nm compared to the healthy skin. A statistically significant decrease in the reflectance of acne lesions was demonstrated for wavelengths: 434, 549, and 588 nm.

CONCLUSIONS

Increased blood perfusion in acne lesions compared to healthy skin suggests increased chemotaxis of inflammatory cells and wound healing. Decrease points in skin reflectance resemble the absorption peaks for hemoglobin and coproporphyrin III produced by Cutibacterium acnes. Thus, the proposed methods may serve not only for the early detection of acne lesions, before they manifest themselves clinically for the naked eye, but may also be a tool for quantifying the effectiveness of acne treatment.

Hyperspectral assessment of acne skin exposed to intense pulsed light (IPL) intense pulsed light in acne treatment

BACKGROUND

The mechanism of intense pulsed light action on the skin is based on selective photothermolysis. The light delivered to the tissue is scattered and absorbed by chromophores that absorb a beam of radiation of a specific length. The skin reflectance changes depending on the physiological state of the tissue, as shown by the hyperspectral camera. The aim of the study was to assess the hyperspectral reflectance of acne skin before and after intense pulsed light (IPL) therapy and to compare it with the reflectance of healthy skin.

MATERIALS AND METHODS

The study involved 27 volunteers with diagnosed moderate acne. The control group consisted of 20 people without acne lesions. All acne volunteers underwent a series of four treatments using IPL at weekly intervals. The volunteers with acne lesions were photographed before the series of treatments and a week after the 4th treatment.

RESULTS

Acne skin shows lower reflectance than healthy skin. Acne skin after IPL therapy is characterized by a higher reflectance compared to acne skin before the therapy and resembles the reflectance of the skin of the control group. A statistically significant difference was found between the acne skin before the treatments and the skin of the control group.

CONCLUSIONS

The effect of IPL therapy on acne skin is the increase of its reflectance by reducing the number of chromophores, which brings it closer to the reflectance value of healthy skin. Hyperspectral imaging allows for: the evaluation of the treated skin at each stage, a precise selection of the light wavelength depending on the problem, and therefore, for optimizing the number of irradiations and increasing the safety of the therapy.