Absence of TLR2 influences survival of neutrophils after infection with Candida albicans

Candida albicans is an opportunistic pathogen, which causes local and/or disseminated diseases in immunosuppressed humans. Phagocytic cells play a critical role in the immune response against C. albicans. Toll like receptors (TLR) are important in the identification of invading microorganisms and in the regulation of neutrophil survival. TLR2 has been shown to participate in the response against pathogenic yeasts and to increase the functional life span of neutrophils. In view of these observations, we studied the involvement of TLR2 in neutrophil function after C. albicans infection. The absence of TLR2 resulted in lower chemotaxis of neutrophils to the site of infection. This in turn was associated with lower levels of chemokines from neutrophils, facilitating the dissemination of the pathogen to the lymph nodes and spleen. A high frequency of apoptotic neutrophils and macrophages in the inflammatory exudates from TLR2(-/-) mice was found. In addition, the phagocytic activity of neutrophils and macrophages, nitric oxide production and myeloperoxidase, activity were diminished in cells from TLR2(-/-) mice. Together, these data demonstrate the importance of TLR2 signals for neutrophils activation and survival after C albicans infection.

Transcriptional response of murine macrophages upon infection with opsonized Paracoccidioides brasiliensis yeast cells

Paracoccidioides brasiliensis is the etiologic agent of the Paracoccidioidomycosis the most common systemic mycosis in Latin America. Little is known about the regulation of genes involved in the innate immune host response to P. brasiliensis. We therefore examined the kinetic profile of gene expression of peritoneal macrophage infected with P. brasiliensis. Total RNA from macrophages at 6, 24 and 48 h was extracted, hybridized onto nylon membranes and analyzed. An increase in the transcription of a number of pro-inflammatory molecules encoding membrane proteins, metalloproteases, involved in adhesion and phagocytosis, are described. We observed also the differential expression of genes whose products may cause apoptotic events induced at 24 h. In addition, considering the simultaneous analyses of differential gene expression for the pathogen reported before by our group, at six hours post infection, we propose a model at molecular level for the P. brasiliensis-macrophage early interaction. In this regard, P. brasiliensis regulates genes specially related to stress and macrophages, at the same time point, up-regulate genes related to inflammation and phagocytosis, probably as an effort to counteract infection by the fungus. (c) 2007 Elsevier Masson SAS. All fights reserved.

Effects of Green Tea Use on Wound Healing

Green tea, a product from Camellia sinensis, consists of over 200 componentes. The most known are the catechins, ou polyphenolic compounds, or flavonoids, but it contains also polysacharide conjugates, amino acids, caffeine and vitamins. Studies have suggested that the regular consumption of green tea reduces the risk of cancer, protecting agains initial events and progression of the disease, may act as antioxidant, has bactericidal properties, and that green tea consumption may be an adjuvant in the treatment of diabetes mellitus, hypertension and hypercholesterolemia. Our experimental study was carried out with male Wistar rats, separated in two groups, experimental and control. The animals in control group were given water ad libitum, and the animals in the experimental group received green tea instead of water. After 2 weeks of experimental period, all the animals, suffered surgical wounds on the dorsum. The animals were sacrificed on I, 3 and 7 days after surgery. Skin samples were used for light microscopy evaluation. Our results allowed us to observe that the experimental group (green tea drinking) presented accelerated epithelial neformation on day 3 after surgery, when epithelial neoformation is in the initial phases. The surgical areas presented 48.20% X 27.32% epithelial neoformation for green tea group and their controls respectivelly at this time. The results of the present study, along with other information about green tea in the literature, strongly suggests that regular use of green tea may be beneficial in surgery situations, when fast epithelial neoformation is desirable.