The phagocytic capacity of neurones.

Phagocytosis is defined as the ingestion of particulates over 0.5 microm in diameter and is associated with cells of the immune system such as macrophages or monocytes. Neurones are not generally recognized to be phagocytic. Using light, confocal, time-lapse and electron microscopy, we carried out a wide range of in-vitro and in-vivo experiments to examine the phagocytic capacity of different neuronal cell types. We demonstrated phagocytosis of material by neurones, including cell debris and synthetic particles up to 2.8 microm in diameter. We showed phagocytosis in different neuronal types, and demonstrated that debris can be transported from neurite extremities to cell bodies and persist within neurones. Flow cytometry analysis demonstrated the lack of certain complement receptors on neurones but the presence of others, including integrin receptors known to mediate macrophage phagocytosis, indicating that a restricted set of phagocytosis receptors may mediate this process. Neuronal phagocytosis occurs in vitro and in vivo, and we propose that this is a more widespread and significant process than previously recognized. Neuronal phagocytosis may explain certain inclusions in neurones during disease, cell-to-cell spread of disease, neuronal death during disease progression and provide a potential mechanism for therapeutic intervention through the delivery of particulate drug carriers.

Vitamin D binding protein in endometriosis.

OBJECTIVE: Two-dimensional gel electrophoresis is a powerful method for identifying post-translationally modified molecules in biological fluids. We examined the presence and expression of vitamin D binding protein (DBP) in the peritoneal fluid (PF) and plasma (PL) of women with endometriosis. METHODS: PL and PF samples were obtained from 36 women with untreated mild endometriosis (revised classification of the American Fertility Society [rAFS] stage I-II), 52 women with untreated severe endometriosis (rAFS stage III-IV), 17 women with endometriosis treated with the oral contraceptive (OC), and 40 controls (infertility, n = 23; tubal sterilization, n = 12; pelvic pain, n = 5). PF and PL samples were analyzed by quantitative, high-resolution 2-dimensional gel electrophoresis. RESULTS: The expression of one DBP isoform (DBPE) in the PF of patients with untreated endometriosis was significantly lower than in the control group (P <.05). The levels of PF DBPE in patients with endometriosis using OC were significantly higher than in women with untreated endometriosis (P <.05). No significant difference was observed in PL DBPE expression between women with and without endometriosis, while it was significantly increased in patients with endometriosis using OC (P <.05). DBP expression was not correlated with the stage of endometriosis (rAFS classification) or the phase of the menstrual cycle. CONCLUSION: The decreased level of DBPE in the PF but not in PL of women with untreated endometriosis suggests that this molecule may be relevant in the pathogenesis of this disease.