Photodynamic therapy in the treatment of xeroderma pigmentosum: A case report.

Xeroderma pigmentosum (XP) is a rare autosomal recessive dermatosis that is often complicated by multiple skin tumours at exposed locations, which are difficult to treat. We report a case of a 12-year-old girl with XP treated with oral retinoic acid and photodynamic therapy (PDT) with good clinical results. She had an 8-year history of multiple skin lesions that first appeared on her nasal dorsum, but gradually increased in size and spread to her entire face, neck, and upper limbs. Notably, the lesions became evidently aggravated after sun exposure. When she was 6 years old, sesame-seed-sized papules and plaques appeared, which were fragile and irregular in shape and would self-rupture, accompanied with slight itchiness and bloody exudate. Examination revealed multiple basal cell carcinomas. The tumours were treated with local carbon dioxide laser therapy combined with PDT. On the follow-up visit 2 months after the surgery, most of the skin lesions on her face had subsided. In cases of multiple tumours, PDT can be the treatment method of choice because it is less invasive, has less side effects, and does not damage the surrounding normal tissues.

Hydroxychloroquine protects melanocytes from autoantibody-induced injury by reducing the binding of antigen-antibody complexes.

Vitiligo is a polygenic autoimmune disorder characterized by loss of pigmentation due to melanocyte destruction. Hydroxychloroquine (HCQ) is an effective immunosuppressant widely used in the treatment of autoimmune disorders. As generalized vitiligo (GV) is commonly considered to be a T cell and autoantibody-induced immune disorder, the present study aimed to determine whether HCQ protects melanocytes from autoantibody­induced disruption. Anti­melanocyte antibodies were obtained from the serum of patients with progressive GV and the effects of HCQ on prevent the autoantibody­induced disruption of melanocytes was observed. Cell­based ELISA, indirect immunofluorescence and western blotting were used to analyze the autoantibody content of sera samples obtained from 32 patients with progressive GV. The cytotoxicity of HCQ was detected by MTT assay, and 1 µg/ml HCQ was applied to human primary melanocytes (HMCs) to examine whether it could exert protective effects against autoantibody­induced immune injury. Flow cytometry was used to measure autoantibody binding to the surface of HMCs. Complement­dependent cytotoxicity (CDC) and antibody­dependent cell­mediated cytotoxicity (ADCC) were monitored by MTT and lactate dehydrogenase­releasing assays. The concentration of autoantibodies in sera samples taken from GV patients was significantly higher than in controls, particularly in patients who had >10% of their body surface affected by vitiligo. The majority of the autoantibodies presented in the HMCs and human keratinocytes (HKCs) and were predominantly localized to the cell surface and cytoplasm. The molecular weights of the autoantigens were identified as 30, 37­39, 42, 53, 60­75, 90, 100, 110, and 126 kDa; the 30 kDa protein was observed only in HMCs. The addition of HCQ at a concentration of 1 µg/ml produced no significant cytotoxicity in HMCs and was demonstrated to reduce the binding of GV immunoglobulin G (IgG) to the surface of HMCs. HCQ also significantly decreased the effects of ADCC and CDC that were mediated by GV IgG. The present study provides evidence that HCQ dissociates autoantibody-antigen complexes on the surface of HMCs and reverses ADCC and CDC activity in vitro. Thus, in addition to its effectiveness as an antimalarial therapeutic agent, HCQ may also be a promising potential treatment for patients with vitiligo.

Efficacy of quantifying melanosome transfer with flow cytometry in a human melanocyte-HaCaT keratinocyte co-culture system in vitro.

In this study, we describe a simple, specific, reproducible and quantitative assay system to assess melanosome transfer. We first established a co-culture model of normal human epidermal melanocytes and HaCaT keratinocytes. The cells were co-cultured for 72 h in a serum-free keratinocyte growth media and double labelled with Fluorescein isothiocyanate (FITC)-conjugated antibody against the melanosome-specific protein gp100, and with Phycoerythrin (PE)-conjugated antibody against the keratinocyte-specific marker cytokeratin. Then, the cells were examined using co-focal microscope and flow cytometry. The increased melanosome transfer from melanocytes to HaCaT keratinocytes was observed in a time-dependent manner. To verify the accessibility of this method, two known melanosome transfer inhibitors and two known melanosome transfer stimulators were applied. Consistent with previous investigation, soybean trypsin inhibitor (STI), niacinamide inhibited melanosome transfer, alpha-melanocyte stimulating hormone (alpha-MSH) and keratinocyte growth factor (KGF) increased melanosome transfer, respectively, in a dose-dependent manner. The model used in this study could thus represent a rapid and reliable tool to identify modulators of human melanosome transfer.

Oligomeric proanthocyanidins from grape seeds effectively inhibit ultraviolet-induced melanogenesis of human melanocytes in vitro.

The oligomeric proanthocyanidins (OPCs) from grape seeds are expected to be novel and potent anti-oxidants that more effectively protect skin cells against oxidative stress. UV-induced oxidative stress is considered to promote melanogenesis and serious skin damage. However, the effect of OPCs on UV-induced melanogenesis is still unknown. To investigate the role of OPCs on melanogenesis of human melanocytes with UV exposure, we evaluated the effects of melanogenesis, cellular cycle, intracellular reactive oxidative species (ROS) level and protein level of melanogenic enzyme in cultured human melanocytes following UV-irradiation by OPCs. After treatment with different doses of OPCs or L-ascorbic acid, normal human melanocytes (NHM) were irradiated by 15 mJ/cm2 UV light. Then, cellular melanin content, activity of tyrosinase were examined. Moreover, the protein analysis of tyrosinase, tyrosinase related protein 1 (TRP1), and tyrosinase related protein 2 (TRP2) were observed by Western blotting. Levels of UV-induced ROS in melanocytes and the responses of cell cycle were also examined by immunofluorescence techniques. This study demonstrated that OPCs, significantly inhibited the cell dead induced by UV irradiation in a dose-dependent manner and OPCs alone, has no effects on melanogenesis of NHM, however, it significantly inhibited UV-induced melanogenesis in a dose-dependent manner. The UV-induced intracellular ROS enhancement was also prevented by addition of OPCs in a dose-dependent manner. Meanwhile, OPCs also inhibited the extent of G1 arrest that was induced by UV exposure. OPCs can decrease the protein level of tyrosinase, TRP1 and TRP2 in UV-irradiated NHM. Thus, OPCs have potential effects of photoprotection on human melanocytes by improving cell viability, scavenging intracellular ROS, adjusting cell cycle and inhibiting protein expression of melanogenic enzymes.