Growth hormone upregulates intestinal trefoil factor expression in the ileum of rats after γ-radiation.

Growth hormone (GH) and intestinal trefoil factor (ITF) have been involved in intestinal protection and repair. This study investigates the effects of GH administration on ITF expression and histological changes associated with tissue injury in an intestinal rat model of radiation. Adult male rats were divided into four groups: control, GH, radiation and radiation + GH (GHyRAD). Ileum samples were obtained at 2 or 72 h after radiation and processed to determine ITF levels (mRNA and protein) by quantitative polymerase chain reaction, Western blot and immunohistochemistry. In addition, goblet ITF-positive cells were identified by immunohistochemistry at 72 h. Our results showed an upregulation of mRNA and protein production of ITF in ileum samples after GH and radiation + GH compared with control and irradiated samples. Irradiation alone affected ITF protein expression. However, irradiation after GH pretreatment produced the highest ITF mRNA and protein levels at both the tested time points. ITF-producing goblet cells were identified in intestinal villi (apical location). GH treatment increased the number of ITF-producing goblet cells, and radiation after GH treatment displayed further increase in the number of ITF-positive goblet cells. GH upregulates ITF in normal intestinal tissue. This upregulation is higher when radiation is given after GH treatment. Nevertheless, the mechanism by which GH regulates ITF expression remains unclear and is still under investigation. These results could open up new avenues in the therapeutic reparative and protective effects of GH during radiotherapy and chemotherapy.

Effects of mannoprotein E1 in liquid diet on inflammatory response and TLR5 expression in the gut of rats infected by Salmonella typhimurium.

BACKGROUND: Mannoproteins are yeast cell wall componend, and rich in mannose. The use of foods rich in mannose as carbohydrate, could have a bioprotective effect against entrobacteria intestinal infection. Nothing is known about mannoproteins' activity in inflammatory bowel processes induced by entrobacteria.This study investigates the effects of mannoprotein administration via a liquid diet on inflammatory response and TLR5 expression during intestinal tissue injury in a rat model of infection with Salmonella typhimurium. METHODS: Adult Wistar male rats were divided into three groups: control, and mannoprotein E1 at 10 or 15%. Animals were fed with a liquid diet supplemented or not with mannoprotein E1. Groups were infected by intragastrical administration of S. typhimurium. 24 h post-inoculation samples of spleen, ileum and liver were collected for microbiological studies. Gut samples were processed to determine levels of proinflammatory cytokines (mRNA) and TLR5 (mRNA and protein) by quantitative PCR and Western-blot, and the number of proliferative and apoptotic cells determined by immunohistochemistry. RESULTS: Ininfected levels of proinflammatory cytokines and TLR5 were higher in untreated controls than in the animals receiving mannoprotein. Proliferation was similar in both groups, whereas apoptosis was higher in controls. Curiosly, the mannoprotein effect was dose dependent. CONCLUSIONS: Mannoprotein administration in a liquid diet seems to protect intestinal tissue against S. typhimurium infection. This protection seems to expressed as a lower pro-inflammatory response and TLR5 downregulation in gut epithelium, as well as by an inhibition of apoptosis. Nevertheless, the molecular mechanism by which mannoprotein is able to regulate these responses remain unclear. These results could open up new avenues in the use of mannoproteins as prebiotics in the therapeutic strategy for treatment of inflammatory gut processes induced by microbia.

Gene expression levels of cytokine profile and cytotoxic markers in non-immediate reactions to drugs.

Drugs can induce IgE mediated or T cell dependent immunological reactions. T cell dependent reactions are poorly understood, although T lymphocytes have been proposed as a protagonist in a number of non-immediate immunological reactions (NIR). The objective was to study in vivo different regulatory and proinflammatory cytokines and cytotoxic markers in patients with NIR to drugs. Twenty patients with NIR after drug intake were classified into two groups: Group A (severe), Stevens-Johnson syndrome and toxic epidermal necrolysis; and Group B (mild), maculopapular exanthema and desquamative exanthema. Another 25 subjects taking the same drugs but without reactions formed a control group. Samples were obtained within 24 hours of the reaction and 30 days later. IL-2, IL-4, IFN, TNF, perforin, granzyme B (GrB), and FasL mRNA expression levels were determined in peripheral blood mononuclear cells by competitive RT-PCR. There were 9 patients in Group A and 11 in Group B. The drugs involved were betalactams (8), anticonvulsants (6), allopurinol (1), sulfamethoxazole (1), amiodarone (1) dypirone (2), and erythromicine+paracetamol (1). At the acute stage there was a high increase of IL-2, IFN, and TNF mRNA expression in both groups vs. controls, perforin and GrB varied in each group with patients in Group A having the highest values, and FasL was only expressed in Group A. Relationships between the cytokines were only significant in Group B (p < 0.05). Only the relation between IFN-gamma and TNF-alpha was significant in Group A. There was a significant correlation between cytotoxic markers in both groups (A: p < 0.001, B: p < 0.01). These data demonstrate the complexity of the Th1 phenotype in NIR after drug intake. In patients with mild NIR, cytokines appear to play a closely related role, whereas cytotoxic markers appear more relevant in severe reactions.

Delayed reactions to drugs show levels of perforin, granzyme B, and Fas-L to be related to disease severity.

BACKGROUND: Drugs can induce different immunologic reactions; T-cell mediated responses produce the most severe reactions. Although in vitro studies show that T cells recognize drugs or their metabolites and induce an effector cytotoxic response, direct in vivo evidence of involvement is lacking. T lymphocytes produce cytotoxic markers that are responsible for 2 major pathways to cell death: granule-mediated exocytosis (perforin and granzyme B) and Fas/FasL interaction. OBJECTIVE: The purpose of this investigation was to establish the role of proinflammatory TNF-alpha and cytotoxic markers in subjects with delayed responses to drugs. METHODS: We assessed expression levels by quantitative-competitive PCR of TNF-alpha, perforin, granzyme B, and FasL in mononuclear cells from peripheral blood and blister fluid from subjects with delayed reactions to drugs. Samples were obtained within 24 hours of the reaction and 30 days later. Fifteen patients were included and classified according to severity of the reaction, as follows: (A) maculopapular exanthema, (B) desquamative exanthema, (C) Stevens-Johnson syndrome, (D) toxic epidermal necrolysis. RESULTS: At the acute stage, there was a large increase in TNF-alpha (9-fold), perforin (6-fold), and GrB (7-fold) in patients in comparison with control subjects. FasL was expressed in PBMCs only in Stevens-Johnson syndrome and toxic epidermal necrolysis. A high association between cytotoxic markers and disease severity was seen (P <.001). CONCLUSION: our data show that TNF-alpha, perforin, GrB, and FasL are increased in the early stage of disease, suggesting that a cytotoxic mechanism might be taking part. These findings support the role of T cells in allergic drug reactions and provide further clues pertaining to therapeutic interventions.