We describe a novel chemical mitogen-free in vitro culture technique for obtaining pure melanocyte cultures using normal human adult epidermis as a source. The culture medium consists equal parts of the commercially available Keratinocyte Basal and AIM-V media (both from Gibco), as basal medium, which is supplemented with fetal bovine serum, bovine pituitary extract and recombinant human epidermal growth factor (EGF). Melanocytes harvested from human adult skin proliferate extensively and can be passaged serially up to 10-15 times using this medium. We have verified the identity of the cultured cells by tyrosinase mRNA expression and TRP-1 protein staining. Moreover, we showed that autologous human serum alone, without additional supplements is able to provide sufficient growth support for the cultured cells in the basal medium, making this culture technique suitable for autologous melanocyte transplantation. In this culture system normal human adult melanocytes expressed both EGF receptor (EGFR) mRNA and protein and EGF showed a dose dependent mitogenic effect on the cells. EGF itself had no significant influence on EGFR mRNA expression.

In previous work we described a novel culture technique using a cholera toxin and PMA-free medium (Mel-mix) for obtaining pure melanocyte cultures from human adult epidermis. In Mel-mix medium the cultured melanocytes are bipolar, unpigmented and highly proliferative. Further characterization of the cultured melanocytes revealed the disappearance of c-Kit and TRP-1 and induction of nestin expression, indicating that melanocytes dedifferentiated in this in vitro culture. Cholera toxin and PMA were able to induce c-Kit and TRP-1 protein expressions in the cells, reversing dedifferentiation. TRP-1 mRNA expression was induced in dedifferentiated melanocytes by UV-B irradiated keratinocyte supernatants, however direct UV-B irradiation of the cells resulted in further decrease of TRP-1 mRNA expression. These dedifferentiated, easily accessible cultured melanocytes provide a good model for studying melanocyte differentiation and possibly transdifferentiation. Because melanocytes in Mel-mix medium can be cultured with human serum as the only supplement, this culture system is also suitable for autologous cell transplantation.

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Syndecan 4 (SDC4), a heparan sulfate proteoglycan, and neuropilin 1 (NRP1), a transmembrane receptor, are both involved in normal wound healing, but little is known about their possible role in venous leg ulcer pathogenesis. We aimed to investigate whether there are any expression abnormalities and/or gene polymorphisms of SDC4 and NRP1 associated with venous leg ulcer. SDC4 showed significantly lower mRNA and protein expression in the uninvolved dermis of venous leg ulcer patients (n=15) compared with controls (n=15; p=0.0136), while NRP1 showed no expression abnormalities. None of the examined SDC4 and NRP1 polymorphisms showed a difference in their allelic distribution between leg ulcer patients (n=92) and controls (n=92). We hypothesize that SDC4 may play an essential role not only in the inflammation and tissue formation phases of normal wound healing, but its expression abnormalities observed in the uninvolved dermis of venous leg ulcer patients may contribute to venous leg ulcer development.

Histamine has been implicated as one of the mediators involved in regulation of proliferation in both normal and neoplastic tissues. Histidine decarboxylase, the only enzyme that catalyzes the formation of histamine from L-histidine, is an essential regulator of histamine levels. In this study, we investigated the gene and protein expression of histidine decarboxylase in melanoma. Reverse transcriptase polymerase chain reaction and in situ hybridization studies of WM-35, WM-983/B, HT-168, and M1 human melanoma cell lines both resulted in positive signals for histidine decarboxylase messenger RNA. A polyclonal chicken antibody was developed against human histidine decarboxylase and protein expression was confirmed by western blot analysis of the cell lysates, revealing a predominant immunoreactive band at approximately 54 kDa corresponding to monomeric histidine decarboxylase. Protein expression of histidine decarboxylase was also shown by flow cytometric analysis and strong punctate cytoplasmic staining of melanoma cell lines. Moreover, both primary and metastatic human melanoma tissues were brightly stained for histidine decarboxylase. When compared with the very weak or no reactions on cultivated human melanocytes both western blot and immunohistochemical studies showed much stronger histidine decarboxylase expression in melanoma cells. These findings suggest that expression of histidine decarboxylase is elevated in human melanoma.

Diabetes mellitus contributes to a number of disorders that can affect the quality of life. Amongst this diabetic foot syndrome and diabetic foot ulceration are serious secondary complications of diabetes mellitus. Persons with diabetic foot ulceration have an increased risk of amputation. In the first part of this review the author focuses on the pathophysiology of diabetic foot ulceration. The second part covers the topics of current and future therapies. The reader will understand the need and modes for preventive measures, the importance of multi level education in this topic, and the need for specialized wound care centers. As emphasized by the author, diabetic foot syndrome and ulceration are serious complications of diabetes mellitus, which can lead to devastating lower-extremity amputations and possible death. Specialized wound care centers, multi level education and proper adherence to standard treatment regimes can potentially prevent the need for amputation.

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