Attenuation by dietary taurine of dextran sulfate sodium-induced colitis in mice and of THP-1-induced damage to intestinal Caco-2 cell monolayers.

The effects of dietary taurine on the experimental colitis induced by dextran sulfate sodium (DSS) in mice were evaluated. C57BL/6 female mice were given 3% DSS in drinking water for 5 d to induce acute colitis. Taurine at 2% was added to the drinking water 5 d before and during the DSS-treatment to investigate its preventive effect. Taurine supplementation significantly attenuated the weight decrease, diarrhea severity, colon shortening, and the increase in the colonic tissue myeloperoxidase activity induced by DSS. Taurine also significantly inhibited the increase in the expression of a pro-inflammatory chemokine, macrophage inflammatory protein 2 (MIP-2), but not of interleukin (IL)-1beta or tumor necrosis factor (TNF)-alpha mRNA. Furthermore, taurine significantly protected the intestinal Caco-2 cell monolayers from the damage by macrophage-like THP-1 cells in an in vitro coculture system. These results suggest that taurine prevented DSS-induced colitis partly in association with (1) its inhibitory effects on the secretion of MIP-2 from the intestinal epithelial cells and on the infiltration of such inflammatory cells as neutrophils and (2) its cytoprotective functions on the epithelial barrier from the direct toxicity of DSS and from the inflammatory cell-induced injury.

Histological and analytical studies of a tooth in a patient with cleidocranial dysostosis.

A histopathological and analytical study of a permanent tooth from a patient with cleidocranial dysostosis (CCD) was performed. The patient was a 47-year-old woman, who had 10 erupted permanent teeth and 2 partially erupted and 19 completely impacted teeth, including supernumerary teeth. The erupted right upper premolar was extracted and observed using a light microscope and an electron probe X-ray microanalyzer (EPMA). Findings showed enamel hypoplasia, predominantly irregular globular dentin and Tomes' granular layer, and a complete lack of cellular cementum in the ground section. The incremental von Ebner and counter Owen lines were obscure. Comparative quantitative analysis using the EPMA showed that the quantities of calcium and phosphate were lower in the enamel and dentin than those of the control sample.

Dietary nucleotides increase the proportion of a TCR gammadelta+ subset of intraepithelial lymphocytes (IEL) and IL-7 production by intestinal epithelial cells (IEC); implications for modification of cellular and molecular cross-talk between IEL and IEC by dietary nucleotides.

We have investigated the effects of dietary nucleotides on intraepithelial lymphocytes (IEL) and intestinal epithelial cells (IEC) in weanling mice. The proportion of T-cell receptor (TCR) gammadelta+ IEL in BALB/c mice fed a diet supplemented with nucleotides (NT(+) diet) was significantly higher than that in mice fed the nucleotide-free diet, while the proportion of TCR alphabeta+ IEL in NT(+) diet-fed mice was significantly decreased. The change of the TCR alphabeta+/TCR gammadelta+ ratio was mainly observed in a CD8 alphaalpha+ subset of IEL. IEC from NT(+) diet-fed mice produced a higher level of IL-7, which is important in the development of TCR gammadelta+ IEL, than those from control diet-fed mice. The expression levels of IL-7 and IL-2 receptors on IEL were not different between the two dietary groups. Our findings suggest that the increased population of a TCR gammadelta+ IEL subset by feeding nucleotides may be caused by the increased production of IL-7 by IEC.