Nimesulide inhibits crypt epithelial cell proliferation at 6 hours in the small intestine in CD-1 mice

STORM: a general model to determine the number and adaptive changes of epithelial stem cells in teleost, murine and human intestinal tracts

Intestinal stem cells play a pivotal role in the epithelial tissue renewal, homeostasis and cancer development. The lack of a general marker for intestinal stem cells across species has hampered analysis of stem cell number in different species and their adaptive changes upon intestinal lesions or during development of cancer. Here a two-dimensional model, named STORM, has been developed to address this issue. By optimizing epithelium renewal dynamics, the model examines the epithelial stem cell number by taking experimental input information regarding epithelium proliferation and differentiation. As the results suggest, there are 2.0-4.1 epithelial stem cells on each pocket section of zebrafish intestine, 2.0-4.1 stem cells on each crypt section of murine small intestine and 1.8-3.5 stem cells on each crypt section of human duodenum. The model is able to provide quick results for stem cell number and its adaptive changes, which is not easy to measure through experiments. Its general applicability to different species makes it a valuable tool for analysis of intestinal stem cells under various pathological conditions.

NSAIDs and Cell Proliferation in Colorectal Cancer

Colon cancer is common worldwide and accounts for significant morbidity and mortality in patients. Fortunately, epidemiological studies have demonstrated that continuous therapy with NSAIDs offers real promise of chemoprevention and adjunct therapy for colon cancer patients. Tumour growth is the result of complex regulation that determines the balance between cell proliferation and cell death. How NSAIDs affect this balance is important for understanding and improving treatment strategies and drug effectiveness. NSAIDs inhibit proliferation and impair the growth of colon cancer cell lines when tested in culture in vitro and many NSAIDs also prevent tumorigenesis and reduce tumour growth in animal models and in patients, but the relationship to inhibition of tumour cell proliferation is less convincing, principally due to gaps in the available data. High concentrations of NSAIDs are required in vitro to achieve cancer cell inhibition and growth retardation at varying time-points following treatment. However, the results from studies with colon cancer cell xenografts are promising and, together with better comparative data on anti-proliferative NSAID concentrations and doses (for in vitro and in vivo administration), could provide more information to improve our understanding of the relationships between these agents, dose and dosing regimen, and cellular environment.

c-Jun, Fra-2, and ATF-2 immunoreactivity in the jejunal tissues of the healthy rat

The aim of this study was to compare the localization of some activator protein-1 (AP-1) proteins in healthy rat jejunum. For this purpose, the AP-1 members c-Jun, Fra-2, and ATF-2 immunoreactivity (c-Jun-IR, Fra-2-IR, ATF-2-IR) in villus epithelial cells (ECs), intravillous lamina propria cells (LPCs), crypt cells (CCs), and smooth muscle cells (SMCs) were analyzed by immunohistochemical methods. Among all the cell groups, the lowest positivity ratio was found in c-Jun-IR and the highest positivity ratio was found in ATF-2-IR. For each group of ECs, LPCs, CCs, and SMCs, c-Jun-IR, Fra-2-IR, and ATF-2-IR were compared and statistically significant differences found. There were no significant differences among the cell groups with respect to c-Jun-IR and Fra-2-IR, but there was a statistically significant difference in ATF-2-IR. These findings suggest that each member of AP-1 is expressed differently and that ATF-2 is more active than c-Jun and Fra-2 in physiological conditions in healthy rat jejunum.

Nimesulide alters cell recruitment into mitosis in murine intestinal crypts without influencing the cell production rate

The use of nonsteroidal anti-inflammatory drugs (NSAIDs) that exhibit COX-2 selectivity is associated with fewer gastrointestinal side effects than seen with more traditional NSAIDs. To determine whether the early effects on cell kinetics in the intestinal mucosal epithelium described after COX-2 selective inhibition are sustained following continuous therapy with these inhibitors, assessments of morphometry and cryptal cell proliferation in the murine small intestinal mucosa were made at 24 hr after treatment with indomethacin, a dual COX inhibitor (10 mg/kg body weight intraperitoneally), nimesulide, a selective COX-2 inhibitor (15 mg/kg body weight intraperitoneally), or vehicle. Nimesulide-treated intestine was elongated beyond control values, in contrast to the shorter indomethacin-treated intestine, but anomalous villous forms were present in both treated groups. Both treatments induced expansion and contraction of proliferating compartments in the crypts in different regions of the intestine but nimesulide did not alter crypt cell production rates, in contrast to the down-regulation induced by indomethacin. These findings may provide some of the fundamental basis for the gut-sparing properties seen in patients treated with COX-2 selective inhibitors.