Infliximab attenuates inflammatory osteolysis in a model of periodontitis in Wistar rats.

Periodontitis is a chronic inflammatory disease related to tooth loss in adults. Infliximab is a chimeric monoclonal antibody against TNF-α and is prescribed for the treatment of systemic inflammatory diseases. This study aimed to investigate the role of infliximab on experimental periodontal disease (EPD). EPD was induced by passing a 3.0 nylon thread around the upper left second molar in Wistar rats. Animals were either treated with intravenous infliximab (1, 5, 7, and 10 mg/kg) or saline solution 30 min before the periodontitis induction and were followed until they were sacrificed on the 11th day. A subset of rats was euthanized on the third day for analysis of gingival myeloperoxidase (MPO) and the blood MPO granulocyte index. In addition, we analyzed the bone loss index (BLI), the periodontal histopathological score, and the periodontal collagen network using confocal microscopy. We also analyzed metalloproteinase-1/-8, RANK, RANK-L, and osteoprotegerin in maxillary tissue by immunohistochemistry Gingival MPO, IL-1ß, TNF-α were measured by ELISA. EPD caused leukocytosis, significant increases in BLI and gingival pro-inflammatory cytokines and cell infiltrates, with worse histopathological scores and periodontal collagen derangement. Infliximab (5 mg/kg) reduced granulocyte blood counts, gingival IL-1ß, TNF-α, and MPO levels, diminished MMP-1/-8, RANK, and RANK-L bone immunolabeling with better periodontal histopathological scores and collagen network in comparison with the challenged saline group. We concluded that infliximab had significant anti-inflammatory and bone-protective effects in Wistar rats challenged by periodontitis.

Role of retinol in protecting epithelial cell damage induced by Clostridium difficile toxin A.

Vitamin A (retinol), a fat-soluble vitamin, is an essential nutrient for the normal functioning of the visual system, epithelial cell integrity and growth, immunity, and reproduction. Our group has investigated the effect of high doses of oral vitamin A on early childhood diarrhea in our prospective community-based studies from Northeast Brazil and found a beneficial role in reducing the mean duration but not incidence of diarrheal episodes. In this study, we explored the role of retinol supplementation in intestinal cell lines following Clostridium difficile toxin A (TxA) challenge. C. difficile is the most common anaerobic pathogen borne with antibiotic-borne diarrhea and pseudomembranous colitis. Since retinol is critical for the integrity of tight junctions and to modulate the cell cycle, we have focused on changes in transepithelial electrical resistance (TEER) in Caco-2, a more differentiated intestinal cell line, and on models of cell proliferation, migration and viability in IEC-6 cells, an undifferentiated crypt cell line, following TxA injury. In this model, retinol therapy reduced apoptosis, improved cell migration and proliferation, and prevented the reduction in TEER, following C. difficile TxA challenge in a glutamine-free medium. These results suggest the role of retinol in protecting intestinal epithelial barrier function from C. difficile TxA enterotoxic damage.