The complement system was analysed in 14 asymptomatic patients with erythropoietic protoporphyria. In the majority of the sera studied the levels of complement components C1, C4, C2, and C3 were within the normal range. Upon ultraviolet light (330--460 nm) irradiation of the serum samples in vitro, a marked decrease in total hemolytic activity accompanied by reduction of C1, C4, C2, and C3 levels was observed. The loss of total hemolytic activity can be directly correlated with the levels of protoporphyrin (PP) and similar changes can be obtained in normal serum upon addition of PP followedf by ultraviolet light irradiation. It is postulated that after irradiation the excited PP develops the capacity to activate the complement sequence with the production of cleavage products, which may contribute to the skin changes observed in these patients upon sun exposure.
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http://dx.doi.org/10.1172/JCI109883 | DOI Listing |
Cell Mol Gastroenterol Hepatol
January 2025
Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, NJ, USA. Electronic address:
Background & Aims: Erythropoietic protoporphyria (EPP) is caused by mutations in ferrochelatase which inserts iron into protoporphyrin-IX (PP-IX) to generate heme. EPP is characterized by PP-IX accumulation, skin photosensitivity, cholestasis, and end-stage liver disease. Despite available drugs that address photosensitivity, treatment of EPP-related liver disease remains an unmet need.
View Article and Find Full Text PDFJ Dermatol
January 2025
Mitsubishi Tanabe Pharma America, Inc., Jersey City, New Jersey, USA.
Ital J Pediatr
December 2024
Department of Medicine, Surgery, and Health Sciences, University of Trieste, Trieste, Italy.
J Med Chem
December 2024
Research Division, Mitsubishi Tanabe Pharma Corporation, 1000 Kamoshida-cho, Aoba-ku, Yokohama 227-0033, Japan.
Activation of the melanocortin 1 receptor (MC1R) mediates melanogenesis in melanocytes, anti-inflammatory effects in inflammatory cells, and antifibrotic effects in fibroblasts. Thus, MC1R agonists are expected to be beneficial for treating skin, autoimmune, inflammatory, and fibrotic diseases. Afamelanotide, an α-melanocyte-stimulating hormone (α-MSH) analogue MC1R agonist, is used clinically for treating erythropoietic protoporphyria (EPP) as a subcutaneous implant formulation.
View Article and Find Full Text PDFNat Commun
December 2024
Center for Pharmacogenetics, Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA, USA.
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