Tea catechins induce crosstalk between signaling pathways and stabilize mast cells in ulcerative colitis.

It is well documented that nutraceuticals, in general, and Green tea catechins, in particular, possess a potential therapeutic value in inflammatory bowel diseases (IBD) due to their anti-oxidative and anti-inflammatory effects. This study aimed to investigate the possible mechanism of action of catechins in a rat model of colitis induced by 2.4.6 trinitrobenzene sulfonic acid (TNBS). Thirty-five young adult Sprague-Dawley rats were divided into four groups: normal control (n=5), catechins (n=9), TNBS (n=9) and TNBS plus catechins (n=12) treated. Catechin in the form of Epigallocatechin-3-gallate (EGCG) was administered daily by intraperitoneal injection, 1 week before the induction date of UC. Biopsies of the descending colon were collected on days 3, 10 and 17, and partly frozen for molecular studies or fixed for light microscopy. The status of intestinal tissue alterations and mast cells number were also assessed, as well as the mRNA expressions of IL-6, TNF-a and NF-kB, and determination of ROS expression. Histological data depicted a significant amelioration in the TNBS- and EGCG-treated rats compared to the non-treated animals. Catechin expressed strong anti-inflammatory and anti-oxidant effects, ameliorated ulcerative colitis and stabilized mast cells. The mechanism of action occurred basically through the NF-kB pathway and possibly through a crosstalk with other pathways.

Oral manifestations of inflammatory bowel disease.

Inflammatory bowel diseases (IBD), including Crohn's disease and ulcerative colitis, have important extraintestinal manifestations, notably in the oral cavity. These oral manifestations can constitute important clinical clues in the diagnosis and management of IBD, and include changes at the immune and bacterial levels. Aphthous ulcers, pyostomatitis vegetans, cobblestoning and gingivitis are important oral findings frequently observed in IBD patients. Their presentations vary considerably and might be well diagnosed and distinguished from other oral lesions. Infections, drug side effects, deficiencies in some nutrients and many other diseases involved with oral manifestations should also be taken into account. This article discusses the most recent findings on the oral manifestations of IBD with a focus on bacterial modulations and immune changes. It also includes an overview on options for management of the oral lesions of IBD.

Polymorphisms of human aryl hydrocarbon receptor (AhR) gene in a French population: relationship with CYP1A1 inducibility and lung cancer.

The Ah receptor (AhR) is a ligand-dependent transcription factor that positively regulates the expression of the CYP1A1 gene. We investigated the genetic polymorphisms of the AhR gene including the promoter, and examined the link between these polymorphisms, CYP1A1 inducibility and the lung cancer incidence. The AhR promoter region and the 11 exons of 30 subjects were screened. Among the three polymorphisms found, two [(2417)(A/G) ((157)G/A)] have never been described previously. The (1721)(G/A) and (2417)(A/G) are localized in exon 10 and lead to Arg(554)Lys and Met(786)Val substitutions, respectively. The other polymorphism was found in the 5'-untranslated region, resulting in the substitution of a G by an A at position 157 (157)(G/A). To evaluate the frequency of this allelic variant found, a DNA library of a case-control study of lung cancer (162 controls and 177 patients) was studied. There is no significant association between (1721)(G/A), (157)(G/A) and lung cancer: (1721)(G/A) and (157)(G/A) were detected at the same allele frequency of 0.086 and 0.25, respectively in both controls and patients. (2417)(A/G) was found in only one control of 100 (allele frequency 0.005). Statistical analysis did not show any relationship between both (1721)(G/A) and (157)(G/A) polymorphisms found and CYP1A1 inducibility. Considering the rareness of the (2417)(A/G) allelic variant we were not able to evaluate its association with inducibility. In conclusion, none of the polymorphisms were found to play a key role in the CYP1A1 inducibility or in the susceptibility to develop lung cancer.

A single d(GpG) cisplatin adduct on the estrogen response element decreases the binding of the estrogen receptor.

Both cisplatin and the estrogen receptor (ER) are known to bend DNA. The influence of the bending of sequences by the d(GpG)cisPt adduct binding of ER to estrogen response element (ERE)-like sequences was examined. Three ERE-like oligonucleotides with different affinities for ER and which include a GG in the linker sequence were designed in order to form a single central d(GpG)cisPt adduct. Using electrophoretic mobility shift assay and Scatchard analysis, it was shown that the presence of a single d(GpG)cisPt adduct in the linker sequence decreases the ER affinity for DNA. These results do not support a critical role of a DNA bend in the initial recognition of ERE by ER. Then, the platination of DNA outside of the ERE half-sites decreases the interaction of ER with ERE.

Phenobarbital prevents the inhibitory effects of tumor necrosis factor on glutathione-S-transferase mu in primary culture rat hepatocytes.

During inflammation and infection, overexpression of the tumor necrosis factor (TNF) is associated with changes in cytochromes P-450 levels in rat and human hepatocytes. The aim of this study was to investigate the effect of TNF on the expression of the glutathione-S-transferases (GSTs) in rat hepatocytes. TNF was added in vitro alone or simultaneously with phenobarbital (PB) into hepatocytes in primary culture or in vivo, before TNF, injected directly to rats. GST activity was assayed by spectrophotometry; protein GSTs alpha, mu and pi were evaluated by immunoblotting. When TNF was added alone to rat hepatocytes in vitro, total GST activity and GST alpha levels were not affected, while GST mu protein levels significantly decreased by 35%. GST pi protein was undetectable in hepatocytes whether treated or not with TNF. When PB was administered in vitro simultaneously to rat hepatocytes with TNF, the decrease observed for GST mu subunit was suppressed while total GST activity and GST alpha content were not affected. When hepatocytes were treated with TNF after PB given in vivo directly to the rat by i.p. injection, GST activity and GSTs subunits were induced by PB, while TNF did not exert any effect. These results indicate that TNF has an inhibitory effect on GST mu and PB abrogates this effect in primary cultured rat hepatocytes. Then, PB could prevent some TNF toxic effects.

Red blood cell glutathione levels before and during treatment with neoadjuvant chemotherapy cisplatin/5-fluorouracil in patients with head and neck squamous cell carcinoma.

The purpose of this study was to find out whether the glutathione (GSH), in red blood cells could predict the response to neoadjuvant chemotherapy cisplatin/5-fluorouracil (CDDP/5-FU) in patients with head and neck squamous cell carcinoma (HNSCC). Three courses of induction chemotherapy with CDDP/5-FU were administered and followed by surgery and radiotherapy or radiotherapy alone, in 51 patients with HNSCC. GSH was measured by spectrophotometry in red blood cell before any treatment (Sample 1: S1), after each course of chemotherapy (S2, S3, S4). Our results showed that GSH was the same at diagnosis in patients with complete or partial response (OR) compared to those with stable or progressive disease (NR). With regard to evolution of the GSH during the 3 courses of CT a significant difference was found between courses (S2: 5.06 +/- 0.35 vs S4 = 3.61 +/- 0.4 mumol/g haemoglobin, p < 0.05). When we separated our patients into OR and NR, a significant difference was found over the 3 courses of chemotherapy for GSH content. Non responder patients showed decreased GSH content at the end of the treatment, (S2: 5 +/- 0.5 vs S4: 2.2 +/- 0.4 mumol/g haemoglobin, p < 0.05) while OR were stable. In conclusion, red blood cell GSH seems to have no early predictive value for chemoresponse to neoadjuvant chemotherapy CDDP/5-FU in HNSCC.

Glutathione system, topoisomerase II level and multidrug resistance phenotype in acute myelogenous leukemia before treatment and at relapse.

In order to better understand acquired resistance to antitumor agents in acute myelogenous leukemia (AML), we investigated various drug resistance mechanisms; namely, topoisomerase II (topo II), glutathione system and P-glycoprotein (P-gp). Blast cells of 31 patients with AML, 21 before treatment (BT) and 10 at relapse (AR) were studied. Topo II was evaluated by Western blot analysis. Glutathione-S-transferase activity (GST) and glutathione content (GSH) were investigated by spectrophotometric assays. GST isoenzymes (-alpha, -mu and -pi) were tested by Western blot and by immunocytochemical staining. P-gp was evaluated by an immunocytochemical method using MRK 16 antibody. Our results showed that GST, GSH and GST-pi were similar in patients BT and AR GST-mu was detected in 13/21 AML BT and in 5/10 AML AR. GST-alpha expression was higher (p < 0.05) in AML AR (60 +/- 105 AU/mg) compared to AML BT (10 +/- 10 AU/mg). A relationship was found between GST-pi quantitation evaluated by Western blot and immunocytochemical staining, whereas no correlation was observed for the other isoenzymes. Topo II was detected in only 4 AML BT and 3 AML AR. Eleven out of 21 AML BT and 3/10 AML AR expressed P-gp with immunohistochemical study. These results indicate that only the "glutathione system", especially the GST-alpha could be involved in drug resistance in AML.