tretinoin and Pseudomonas-Infections

Use of the ablative laser has been approved to enhance topical drug penetration. Investigation into the usefulness of the non-ablative laser for assisting drug delivery is very limited. In this study, we explored the safety and efficacy of the non-ablative fractional erbium:glass (Er:glass) laser as an enhancement approach to promote drug permeation. Both pig and nude mouse skins were employed as transport barriers. We histologically examined the skin structure after laser exposure. The permeants of 5-aminolevulinic acid (ALA), imiquimod, tretinoin, peptide, dextrans and quantum dots (QD) were used to evaluate in vitro and in vivo skin passage. The fractional laser selectively created an array of photothermal dots deep into the dermis with the preservation of the stratum corneum and epidermis. The barrier function of the skin could be recovered 8-60h post-irradiation depending on the laser spot densities. The application of the laser caused no local infection of Staphylococcus aureus and Pseudomonas aeruginosa. Compared to intact skin, ALA flux was enhanced up to 1200-fold after laser exposure. The penetration enhancement level by the laser was decreased following the increase of permeant lipophilicity. The skin accumulation of tretinoin, an extremely lipophilic drug, showed only a 2-fold elevation by laser irradiation. The laser promoted peptide penetration 10-fold compared to the control skin. Skin delivery of dextrans with a molecular weight (MW) of at least 40kDa could be achieved with the Er:glass laser. QD with a diameter of 20nm penetrated into the skin with the assistance of the non-ablative laser. The confocal microscopic images indicated the perpendicular and lateral diffusions of dextrans and nanoparticles via laser-created microscopic thermal zones. Controlled Er:glass laser irradiation offers a valid enhancement strategy to topically administer the permeants with a wide MW and lipophilicity range.

Topics: Administration, Cutaneous; Aminolevulinic Acid; Aminoquinolines; Animals; Dextrans; Drug Delivery Systems; Fluorescein; Fluorescein-5-isothiocyanate; Imiquimod; Lasers, Solid-State; Mice, Inbred BALB C; Mice, Nude; Peptides; Pseudomonas aeruginosa; Pseudomonas Infections; Quantum Dots; Skin; Skin Absorption; Staphylococcal Infections; Staphylococcus aureus; Swine; Tretinoin

Human skin is able to mount a fast response against invading harmful bacteria through the rapid production of inducible peptide antibiotics such as the human beta-defensins (hBD). To gain more insight into the role and regulation of inducible beta-defensins in the innate immunity of human skin, we investigated whether gene induction of the human beta-defensins hBD-1, -2, -3, and -4 in keratinocytes is regulated in a similar manner. Therefore, we performed a comparative study of gene expression of these four hBD in primary cultured keratinocytes using real-time PCR. A basal mRNA expression was observed for all four hBD in primary keratinocytes, which strongly increased for hBD-2, -3, and -4 during Ca(2+)-induced differentiation of the keratinocytes. This effect was completely abolished when the keratinocytes were pre-treated with all-trans-retinoic acid (RA). Furthermore, the differential induction of hBD-2, -3, and -4 gene expression in keratinocytes by proinflammatory cytokines, phorbol-myristate-acetate (PMA), and bacteria was inhibited by more than 90% when the keratinocytes were pre-incubated with RA. Inhibition of IL-1beta-mediated hBD-2 induction through RA was further confirmed by gene reporter assays and western-blot analysis. We conclude that RA is a potent inhibitor of beta-defensin induction in keratinocytes and might downregulate the inducible innate chemical defense system of human skin.

Topics: Antineoplastic Agents; beta-Defensins; Calcium; Carcinogens; Cells, Cultured; Gene Expression Regulation; Humans; Interferon-gamma; Interleukin-1; Keratinocytes; Pseudomonas aeruginosa; Pseudomonas Infections; RNA, Messenger; Tetradecanoylphorbol Acetate; Transcriptional Activation; Tretinoin; Tumor Necrosis Factor-alpha; Up-Regulation

We observed a child with acute promyelocytic leukemia (APL) who, at the onset, had extremely severe hemorrhagic and septic complications. According to our experience in Nicaragua, there was a very high risk of early death. The patient was successfully treated with a program that included all-trans retinoic acid (ATRA) followed by cytotoxic chemotherapy. ATRA has two important features: it is effective in initial treatment of APL and it is inexpensive. Because of the high cost and the need for extensive supportive care, optimal myeloablative therapy used in patients with various types of acute myeloid leukemia generally cannot be given in developing countries. ATRA treatment for APL is affordable everywhere.

Topics: Antineoplastic Agents; Bacteremia; Child; Developing Countries; Drug Costs; Female; Hemorrhage; Humans; Leukemia, Promyelocytic, Acute; Nicaragua; Pseudomonas aeruginosa; Pseudomonas Infections; Remission Induction; Skin Diseases, Bacterial; Staphylococcal Skin Infections; Tretinoin