High doses of laser phototherapy can increase proliferation in melanoma stromal connective tissue.

It is well established that laser phototherapy (LP) is contraindicated directly over cancer cells, due to its bio modulatory effects in cell and blood vessel proliferation. The aim of the present study was to analyze the influence of typical low-level laser therapy (LLLT) and high intensity laser therapy (HILT) and an in-between dose of 9 J on collagen fibers and blood vessels content in melanoma tumors (B16F10) implanted in mice. Melanoma tumor cells were injected in male Balb C mice which were distributed in four groups: control (no irradiated) or irradiated by 3, 9, or 21 J (150; 450, or 1050 J/cm2). LP was performed in daily sessions for 3 days with a InGaAlP-660 nm (mean output: 50 mW, spot size: 2 mm2). Tumor volume was analyzed using (1) picrosirius staining to quantify collagen fibers content and (2) Verhoeff's method to quantify blood vessels content. Tumor growth outcome measured in the 3-J group was not significantly different from controls. Nine and 21-J groups, presented significant and dose-dependent increases in tumor volume. Quantitative analysis of the intensity of collagen fibers and their organization in stroma and peri-tumoral microenvironment showed significant differences between irradiated and control group. Blood vessels count of 21-J group outnumbered the other groups. High doses (≥ 9 J) of LP showed a dose-dependent tumor growth, different collagen fibers characteristics, and eventually blood vessel growth, while a typical LLLT dose (3 J) appeared harmless on melanoma cell activity.

Laser photobiomodulation in pressure ulcer healing of human diabetic patients: gene expression analysis of inflammatory biochemical markers.

Pressure ulcers (PU) are wounds located mainly on bone surfaces where the tissue under pressure suffers ischemia leading to cellular lesion and necrosis , its causes and the healing process depend on several factors. The aim of this study was evaluating the gene expression of inflammatory/reparative factors: IL6, TNF, VEGF, and TGF, which take part in the tissue healing process under effects of low-level laser therapy (LLLT). In order to perform lesion area analysis, PUs were photographed and computer analyzed. Biochemical analysis was performed sa.mpling ulcer border tissue obtained through biopsy before and after laser therapy and quantitative real-time PCR (qRT-PCR) analysis. The study comprised eight individuals, mean age sixty-two years old, and sacroiliac and calcaneous PU, classified as degree III and IV according to the National Pressure Ulcer Advisory Panel (NPUAP). PUs were irradiated with low-level laser (InGaAIP, 100 mW, 660 nm), energy density 2 J/cm2, once a day, with intervals of 24 h, totaling 12 applications. The lesion area analysis revealed averaged improvement of the granulation tissue size up to 50% from pre- to post-treatment. qRT-PCR analysis revealed that IL6 values were not significantly different before and after treatment, TNF gene expression was reduced, and VEFG and TGF-ß gene expression increased after treatment. After LLLT, wounds presented improvement in gross appearance, with increase in factors VEFG and TGF-ß, and reduction of TNF; despite our promising results, they have to be analyzed carefully as this study did not have a control group.

High doses of laser phototherapy can increase proliferation in melanoma stromal connective tissue

It is well established that laser phototherapy (LP) is contraindicated directly over cancer cells, due to its bio modulatory effects in cell and blood vessel proliferation. The aim of the present study was to analyze the influence of typical low-level laser therapy (LLLT) and high intensity laser therapy (HILT) and an in-between dose of 9 J on collagen fibers and blood vessels content in melanoma tumors (B16F10) implanted in mice. Melanoma tumor cells were injected in male Balb C mice which were distributed in four groups: control (no irradiated) or irradiated by 3, 9, or 21 J (150; 450, or 1050 J/cm2). LP was performed in daily sessions for 3 days with a InGaAlP—660 nm (mean output: 50 mW, spot size: 2 mm2). Tumor volume was analyzed using (1) picrosirius staining to quantify collagen fibers content and (2) Verhoeff’s method to quantify blood vessels content. Tumor growth outcome measured in the 3-J group was not significantly different from controls. Nine and 21-J groups, presented significant and dose-dependent increases in tumor volume. Quantitative analysis of the intensity of collagen fibers and their organization in stroma and peri-tumoral microenvironment showed significant differences between irradiated and control group. Blood vessels count of 21-J group outnumbered the other groups. High doses (= 9 J) of LP showed a dose-dependent tumor growth, different collagen fibers characteristics, and eventually blood vessel growth, while a typical LLLT dose (3 J) appeared harmless on melanoma cell activity

Anti-proliferative and anti-inflammatory effects of 3ß,6ß,16ß-Trihydroxylup-20(29)-ene on cutaneous inflammation.

ETHNOPHARMACOLOGICAL RELEVANCE: 3ß,6ß,16ß-Trihydroxylup-20(29)-ene (TTHL) is a triterpene isolated from the flowers of Combretum leprosum, a plant used in folk medicine in the north of Brazil for the treatment of skin disorders. AIM OF THE STUDY: In the present study, TTHL was evaluated as a potential topical anti-inflammatory and anti-proliferative agent through in vivo and in vitro models. MATERIAL AND METHODS: Anti-inflammmatory and anti-proliferative effects of TTHL were assessed using Swiss mice in acute and chronic models of skin inflammation induced by 12-O-tetradecanoylphorbol-acetate (TPA) application. Anti-proliferative activity was proved through in vitro experiments with the HaCaT human keratinocyte cell line. RESULTS: Treatment with TTHL inhibited inflammatory parameters such as oedema formation and cellular infiltration in acute and chronic models. In the chronic model, TTHL also inhibited epidermal hyperproliferation, as evidenced by reduction of epidermis thickness and proliferating cell nuclear antigen expression. The anti-proliferative effect was confirmed by the capability of TTHL in reducing the proliferation and inducing cell apoptosis of HaCaT cells. Suggesting a mechanism of action, TTHL showed activation of corticosteroid receptors, but without the induction of corticosteroid-related cutaneous side effects. CONCLUSION: Our results demonstrate consistent anti-inflammatory and anti-proliferative activity and assign TTHL as a valuable tool in the development of a new treatment for skin inflammatory and proliferative diseases, such as psoriasis.

Inhibitory effect of GB-2a (I3-naringenin-II8-eriodictyol) on melanogenesis.

ETHNOPHARMACOLOGY RELEVANCE: GB-2a is a I3-naringenin-II8-eriodictyol compound isolated from Garcinia gardneriana (Planchon & Triana) Zappi, a plant used in folk medicine for the treatment of skin disorders. AIM OF STUDY: In the search for new depigmenting agents, this study was carried out to investigate the in vitro effects of GB-2a isolated from G. gardneriana (Planchon & Triana) Zappi in B16F10 melanoma cells. MATERIALS AND METHODS: The effects of GB-2a were evaluated through determination of melanin biosynthesis in B16F10 melanoma cells in comparison with the reference drug kojic acid (500µM). In parallel, the GB-2a effect was assessed in a cell viability assay. Mushroom tyrosinase activity assays were conducted to verify the effect of this enzyme. In order to ascertain the nature of enzyme inhibition on tyrosinase, kinetics analysis of the GB-2a was performed with L-tyrosine and L-3,4-dihydroxyphenylalanine (L-DOPA) substrates. RESULTS: The results showed that GB-2a biflavonoid significantly inhibited the melanin content, without reducing cell viability. GB-2a also showed a strong antityrosinase activity in the mushroom tyrosinase assay. GB-2a inhibited the tyrosinase activity, exerting a mixed inhibition. For the L-tyrosine substrate the inhibition was in non-competitive mode and for L-DOPA it was in uncompetitive mode. CONCLUSION: GB-2a biflavonoid promoted inhibition on tyrosinase activity and reduced melanin biosynthesis in B16F10 cells, which suggests great potential for medical and cosmetic uses as a depigmenting agent.

Antitumoural effect of Synadenium grantii Hook f. (Euphorbiaceae) latex.

ETHNOPHARMACOLOGICAL RELEVANCE: Synadenium grantii Hook f. has traditionally been used to treat various neoplastic diseases in southern Brazil. AIM OF STUDY: Evaluation of the antitumoural potential of Synadenium grantii latex against B16F10 melanoma cell line using in vitro and in vivo models, as well as a phytochemical study of the latex. MATERIALS AND METHODS: The in vitro antitumoural activity was performed using MTT and trypan blue assays with different latex concentrations (1.7 µg-7.0 µg/well and 1.22 mg-4.88 mg/well). Flow cytometry was used to determine the progression of the cell cycle. The in vivo activity was performed by subcutaneously injecting melanoma cells in the dorsum of C57BL6 mice, followed by treating the mice with a popular form of use of the latex (garrafada) administered orally. After sacrificing the animals, histological analysis of the organs was performed by hematoxylin-eosin staining. The phytochemical study of the latex was performed by NMR and chromatographic procedures and the extracts and isolated substances were evaluated by IR, 1D and 2D NMR analysis. RESULTS: The Synadenium grantii latex exhibited decreased cell viability of the melanoma line in a concentration and time-dependent manner, and also cell cycle arrest in the S-G2/M phase. The latex caused a 40% reduction in the volume of tumours of the mice with melanomas. Histological examination of the organs of these animals showed no differences between groups. The phytochemical investigation resulted in the isolation and identification of triterpene euphol and the steroid citrostadienol, which were tested against the strain of melanoma. Euphol showed no antitumoural activity, while the steroid citrostadienol showed reduced cytotoxic activity. CONCLUSION: The Synadenium grantii latex presented in vitro and in vivo cytotoxic effects with antitumoural activity against B16F10 melanoma cells.

In vitro analysis of human tooth pulp chamber temperature after low-intensity laser therapy at different power outputs.

In vitro studies have provided conflicting evidence of temperature changes in the tooth pulp chamber after low-level laser irradiation of the tooth surface. The present study was an in vitro evaluation of temperature increases in the human tooth pulp chamber after diode laser irradiation (GaAlAs, λ = 808 nm) using different power densities. Twelve human teeth (three incisors, three canines, three premolars and three molars) were sectioned in the cervical third of the root and enlarged for the introduction of a thermocouple into the pulp chamber. The teeth were irradiated with 417 mW, 207 mW and 78 mW power outputs for 30 s on the vestibular surface approximately 2 mm from the cervical line of the crown. The highest average increase in temperature (5.6°C) was observed in incisors irradiated with 417 mW. None of the teeth (incisors, canines, premolars or molars) irradiated with 207 mW showed temperature increases higher than 5.5°C that could potentially be harmful to pulp tissue. Teeth irradiated with 78 mW showed lower temperature increases. The study showed that diode laser irradiation with a wavelength of 808 nm at 417 mW power output increased the pulp chamber temperature of certain groups of teeth, especially incisors and premolars, to critical threshold values for the dental pulp (5.5°C). Thus, this study serves as a warning to clinicians that "more" is not necessarily "better".