Expression of the complete CRH system is abundant in acne-involved skin, especially in the sebaceous glands, possibly activating pathways which affect immune and inflammatory processes leading to the development and stress-induced exacerbation of acne.

Central or peripheral stress may induce the development of clinical inflammation in the pilosebaceous unit, leading to the development of acne lesions or to exacerbation of pre-existing acne. Melanocortin peptides such as alpha-melanocyte-stimulating hormone and its receptors do not only regulate melanogenesis but can also affect non-pigmentary processes, such as inflammation, apoptosis and sebogenesis. The purpose of the study was to investigate by immunohistochemistry if changes of melanocortin-1 receptor expression exist in acne lesions versus normal skin. In all, 33 patients with acne vulgaris and seven age-matched volunteers without acne participated in the study. Skin biopsies were taken from acne-involved faces, the non-involved thigh skin of the same patients and from normal human skin. Melanocortin-1 receptor immunoreactivity was most prominently detectable in adnexal structures. Sebocytes and keratinocytes of the ductus seboglandularis of acne-involved and non-involved skin showed very intense melanocortin-1 receptor expression in contrast to less intense scattered immunoreactivity in normal skin samples. These data suggest that melanocortin-1 receptor is involved in the pathogenesis of acne.

The inflamed synovium of rheumatoid arthritis exhibits many features typical for neoplastic tissue implying that the photodynamic therapy might be an efficient modality for chronic poliarthritis. The accumulation of endogenously produced porphyrins after administration of exogenous 5-aminolevulinic acid (ALA) in a rabbit model of rheumatoid arthritis was evaluated by fluorescence spectroscopy. Independent of the way, intravenously or intra-articularly, in which ALA was administered to the experimental animals, the highest fluorescence intensity of endogenously produced porphyrins was detected in the tissues of the inflamed joints. Besides, the application of ALA had a systemic sensitising effect on the whole organism of rabbits. The highest amount of endogenously produced porphyrins in the inflamed joints measured from the surface of the skin above the synovium tissues was detected 1-3 h after the administration of ALA. Fluorescence measurements performed on the tissue specimens ex vivo showed the predominant accumulation of porphyrins in the synovium of the inflamed joints. The fluorescence of porphyrins was also observed in the cartilage tissues taken from knee joints. However, the fluorescence spectra features indicated that the composition of porphyrins detected in the cartilage tissues was different than that in the synovial tissues. The selective accumulation of porphyrins in the inflamed synovial tissues stands up for the application of photodynamic therapy in the treatment of rheumatoid arthritis and implies the possibility to use optical non-invasive methods based on fluorescence detection of endogenously produced porphyrins for diagnostics of inflamed tissues.

No abstract

No abstract