Repeated concanavalin A challenge in mice induces an interleukin 10-producing phenotype and liver fibrosis.

Weekly injections of Concanavalin A (Con A) were performed in BALB/c mice to evaluate the pattern of cytokine production and liver injury. High serum levels of tumor necrosis factor alpha (TNF-alpha), interleukin 2 (IL-2), IL-4, and interferon gamma (IFN-gamma) were found in the serum after the first 2 injections of Con A but rapidly decreased from the third injection. Conversely, IL-10 serum levels after repeated Con A challenge increased by 7 times from week 1 to 20. In vivo depletion studies indicated that CD4(+) T cells are essential in IL-10 production. Hepatocyte necrosis was only observed after the first injections of Con A whereas centrilobular inflammatory infiltrates persisted up to 20 weeks. Perisinusoidal liver fibrosis was also increasingly detected in BALB/c mice, whereas no fibrous change was observed in nude mice after 6 weeks of Con A challenge. The number of stellate cells, detected by immunostaining, increased after 20 weeks of Con A injections. Liver cytokine messenger RNA (mRNA) expression after 20 weeks showed expression of transforming growth factor beta1 (TGF-beta1), IL-10, and IL-4 whereas IL-2 was no more expressed. The present study shows that mice repeatedly injected with Con A develop liver fibrosis. The cytokine-release pattern observed after 1 injection of Con A is rapidly shifted towards an immunomodulatory phenotype characterized by the systemic production of large amounts of IL-10.

Interleukin 10 reduces the incidence of pancreatitis after therapeutic endoscopic retrograde cholangiopancreatography.

BACKGROUND & AIMS: Prophylactic administration of interleukin (IL)-10 decreases the severity of experimental pancreatitis. Prevention of post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis in humans is a unique model to study the potential role of IL-10 in this setting. METHODS: In a single-center, double-blind, randomized, placebo-controlled study, the effect of a single injection of 4 microg/kg (group 1) or 20 microg/kg (group 2) IL-10 was compared with that of placebo (group 0), all administered 30 minutes before therapeutic ERCP. The primary endpoint was the effect of IL-10 on serum levels of amylases and lipases measured 4, 24, and 48 hours after ERCP. The secondary objective was to evaluate changes in plasma cytokines (IL-6, IL-8, tumor necrosis factor) at the same time points and the incidence of acute pancreatitis in the 3 groups. Subjects undergoing a first therapeutic ERCP were eligible for inclusion. RESULTS: A total of 144 patients were included. Seven were excluded based on intention to treat (n = 1) or per protocol (n = 6). Forty-five, 48, and 44 patients remained in groups 0, 1, and 2, respectively. The 3 groups were comparable for age, sex, underlying disease, indication for treatment, type of treatment, and plasma levels of C-reactive protein (CRP), cytokines, and hydrolases at baseline. No significant difference was observed in CRP, cytokine, and hydrolase plasma levels after ERCP. Forty-three patients developed hyperhydrolasemia (18 in group 0, 14 in group 1, and 11 in group 2; P = 0.297), and 19 patients developed acute clinical pancreatitis (11 in group 0, 5 in group 1, 3 in group 2; P = 0.038). Two severe cases were observed in the placebo group. No mortality related to ERCP was observed. Logistic regression identified 3 independent risk factors for post-therapeutic ERCP pancreatitis: IL-10 administration (odds ratio [OR], 0.46; 95% confidence interval [95% CI], 0.22-0.96; P = 0.039), pancreatic sphincterotomy (OR, 5.04; 95% CI, 1.53-16.61; P = 0.008), and acinarization (OR, 8.19; 95% CI, 1.83-36.57; P = 0.006). CONCLUSIONS: A single intravenous dose of IL-10, given 30 minutes before the start of the procedure, independently reduces the incidence of post-therapeutic ERCP pancreatitis.

Critical role of interleukin 5 and eosinophils in concanavalin A-induced hepatitis in mice.

BACKGROUND & AIMS: Eosinophils are observed in several liver diseases, but their contribution in the pathogenesis of these disorders remains poorly investigated. Concanavalin A (Con A)-induced hepatitis is an experimental model of immune-mediated liver injury in which natural killer T (NKT) cells play a critical role through the production of interleukin (IL)-4 and the expression of Fas ligand (FasL). Because activated NKT cells also produce IL-5, a critical cytokine for eosinophil maturation and function, the role of IL-5 was investigated in this model. METHODS: IL-5-deficient mice, eosinophil depletion in wild-type (WT) mice, and NKT cell transfer from WT- or IL-5-deficient mice into NKT cell-deficient mice were used to assess the role of IL-5 and eosinophils. RESULTS: Liver eosinophil infiltrate and IL-5 production were observed after Con A challenge. Liver injury was dramatically reduced in IL-5-deficient or eosinophil-depleted mice. In addition, residual hepatitis observed in Fas-deficient mice was abolished after IL-5 neutralization. Finally, we showed that NKT cells constituted a critical source of IL-5. Indeed, transfer of WT NKT cells to mice lacking NKT cells restored liver injury, whereas transfer of IL-5-deficient NKT cells did not. CONCLUSIONS: These observations highlight the pathologic role of IL-5 and eosinophils in experimental immune-mediated hepatitis.

Endogenous interleukin-10 modulates fibrosis and regeneration in experimental chronic pancreatitis.

Interleukin (IL)-10, a potent anti-inflammatory cytokine, limits the severity of acute pancreatitis and downregulates transforming growth factor (TGF)-beta release by inflammatory cells on stimulation. Proinflammatory mediators, reactive oxygen species, and TGF-beta can activate pancreatic stellate cells and their synthesis of collagen I and III. This study evaluates the role of endogenous IL-10 in the modulation of the regeneration phase following acute pancreatitis and in the development of pancreatic fibrosis. IL-10 knockout (KO) mice and their C57BL/6 controls were submitted to repeated courses (3/wk, during 6 wk, followed by 1 wk of recovery) of cerulein-induced acute pancreatitis. TGF-beta(1) release was measured on plasma, and its pancreatic expression was assessed by quantitative RT-PCR and immunohistochemistry. Intrapancreatic IL-10 gene expression was assessed by semiquantitative RT-PCR, and intrapancreatic collagen content was assessed by picrosirius staining. Activated stellate cells were detected by immunohistochemistry. S phase intrapancreatic cells were marked using tritiated thymidine labeling. After repeated acute pancreatitis, IL-10 KO mice had more severe histological lesions and fibrosis (intrapancreatic collagen content) than controls. TGF-beta(1) plasma levels, intrapancreatic transcription, and expression by ductal and interstitial cells, as well as the number of activated stellate cells, were significantly higher. IL-10 KO mice disclosed significantly fewer acinar cells in S phase, whereas the opposite was observed for pseudotubular cells. Endogenous IL-10 controls the regeneration phase and limits the severity of fibrosis and glandular atrophy induced by repeated episodes of acute pancreatitis in mice.

Dose-effect of interleukin-10 and its immunoregulatory role in Crohn's disease.

BACKGROUND: Interleukin-10 (IL-10) is currently being extensively studied in clinical trials for the treatment of Crohn's disease (CD). Only marginal effects have, however, been reported, and the dose-response curve was bell-shaped contrasting with the reported data from in vitro experiments. AIM: To use another in vitro model to analyze the effect of rhIL-10 and rhIL-4 on the spontaneous mucosal TNF-alpha secretion in patients with CD, and to characterize the phenotype of the cells targeted by rhIL-10. METHODS: Non-inflamed colon biopsies from CD patients were cultured for 16 hours in presence of different concentrations of rhIL-10 or rhIL-4. The numbers of TNF-alpha-secreting cells among isolated lamina propria mononuclear cells (LPMNC) were estimated by Elispot. RESULTS: Both rhIL-10 and rhIL-4 down-regulate TNF-alpha secretion by LPMNC from CD patients, with a more pronounced effect with rhIL-10. These effects were closely linked to the cytokine concentrations used, with a bell-shaped dose-response curve. Residual TNF-alpha secretion, in the presence of optimal rhIL-10 concentration was mainly attributable to CD3+ T cells. In contrast, at higher rhIL-10 concentrations, CD3- cells contributed significantly to the TNF-alpha secretion. CONCLUSIONS: The in vitro model we used, demonstrates that IL-4, but mostly IL-10, efficiently suppresses TNF-alpha secretion in LPMNC from CD patients, with a dose-response curve similar to results obtained in vivo. Resistance at high rhIL-10 concentrations was associated with a change in the phenotype of TNF-alpha-secreting cells.

Diversion of intestinal flow decreases the numbers of interleukin 4 secreting and interferon gamma secreting T lymphocytes in small bowel mucosa.

BACKGROUND/AIMS: The intestinal immune system faces large amounts of antigens, and its regulation is tightly balanced by cytokines. In this study, the effect of intestinal flow diversion on spontaneous secretion of interleukin (IL)-4 and interferon (IFN)- gamma was analysed. METHODS: Eight patients (two with Crohn's disease, four with ulcerative colitis, and two with previous colon cancer) carrying a double lumen small bowel stoma after a total colectomy procedure were included in the study. For each patient, eight biopsy samples were taken endoscopically from both the diverted and non-diverted part of the small bowel. Intraepithelial lymphocytes (IELs) and lamina propria lymphocytes (LPLs) were isolated separately and assayed for numbers of cells spontaneously secreting IL-4 and/or IFN-gamma by an ELISPOT technique. RESULTS: Compared with the non-diverted mucosa, a significant decrease in the number of spontaneously IFN-gamma secreting CD3 lymphocytes was observed in the diverted small bowel mucosa among both IELs (p = 0.008) and LPLs (p = 0.007). The same results, although less significant, were obtained for IL-4, especially in LPLs (p = 0.01). CONCLUSION: The intestinal content influences the spontaneous secretion of IFN-gamma and IL-4 by intestinal lymphocytes. These results could help to elucidate the anti-inflammatory role of split ileostomy in patients suffering from inflammatory bowel diseases.

Spontaneous secretion of interferon gamma and interleukin 4 by human intraepithelial and lamina propria gut lymphocytes.

BACKGROUND: Cytokines secreted by intestinal T lymphocytes probably play a critical role in regulation of the gut associated immune responses. AIMS: To quantify interferon gamma (IFN-gamma) and interleukin 4 (IL-4) secreting cells (SC) among human intraepithelial (IEL) and lamina propria (LPL) lymphocytes from the duodenum and right colon in non-pathological situations and in the absence of in vitro stimulation. PATIENTS: Duodenal and right colonic biopsy specimens were obtained from patients with no inflammation of the intestinal mucosa. METHODS: Intraepithelial and lamina propria cell suspensions were assayed for numbers of cells spontaneously secreting IFN-gamma and IL-4 by a two site reverse enzyme linked immunospot technique (ELISPOT). RESULTS: The relatively high proportion of duodenal lymphocytes spontaneously secreting IFN-gamma (IEL 3.6%; LPL 1.9%) and IL-4 (IEL 1.3%; LPL 0.7%) contrasted with the very low numbers of spontaneously IFN-gamma SC and the absence of spontaneously IL-4 SC among peripheral blood mononuclear cells. In the basal state, both IFN-gamma and IL-4 were mainly produced by CD4+ cells. Within the colon, only 0.2% of IEL and LPL secreted IFN-gamma in the basal state, and 0.1% secreted IL-4. CONCLUSIONS: Compared with peripheral lymphocytes substantial proportions of intestinal epithelial and lamina propria lymphocytes spontaneously secrete IFN-gamma and/or IL-4. These cytokines are probably involved in the normal homoeostasis of the human intestinal mucosa. Disturbances in their secretion could play a role in the pathogenesis of gastrointestinal diseases.

Development of a new blood test based on the helper lymphocytes Th-17 response for the diagnosis of allergies to dental metals: Preliminary results

info:eu-repo/semantics/nonPublished

Thyroid volumes and urinary iodine in Swiss school children, 17 years after improved prophylaxis of iodine deficiency

Salt iodine content in Switzerland was raised from 7.5 to 15 mg per kg in 1980, and since then dietary iodine intake has been considered to be sufficient, even though a slight decrease due to imported food has recently been reported. The aim of this study was to establish normal values for thyroid volumes of school children who can be assumed to have had a sufficient iodine intake all their lifetime. Moreover, the present investigation was undertaken to verify that iodine sufficiency had been achieved equally in two regions each served by one of the two Swiss salt producers. Mean iodine concentration in urine spot samples from school children was 16.1 μg/dl, and it was identical in both the city of Lausanne (n=215) and the city of Solothurn (n=208). Thus it can be stated that in both cities (served by two different salt producers) iodine intake is equal and sufficient. Accordingly, thyroid volumes measured by ultrasound in school children aged 6 to 16 years were the same in both Lausanne (n=202) and Solothurn (n=207). Moreover, the age-adjusted median volumes at the 97th percentiles closely agree with and validate provisional international reference values recently proposed by the World Health Organisation and by the International Council for Control of Iodine Deficiency Disease.

Cellular immune responses of preterm infants after vaccination with whole-cell or acellular pertussis vaccines.

Based on studies reporting specific antibody titers, it is recommended to vaccinate preterm infants against Bordetella pertussis according to their chronological age. However, as specific T-cell responses also are involved in the protection against B. pertussis, we have determined whether highly preterm infants (<31 weeks) are able to mount these immune responses during vaccination. Forty-eight premature infants were vaccinated at 2, 3, and 4 months of their chronological age with an acellular (Pa; n = 24) or a whole-cell (Pw; n = 24) tetravalent diphtheria-tetanus-pertussis-polio vaccine, and blood samples were collected at 2, 3, and 6 months of age. Most of the Pa- and Pw-vaccinated infants developed at 3 or 6 months of age a gamma interferon (IFN-gamma) response to the B. pertussis antigens, accompanied by an interleukin-5 (IL-5) and IL-13 secretion for the Pa-vaccinated infants. No association was found between a very low infant birth weight, the occurrence of severe infections, and corticosteroid treatment or the administration of gammaglobulins with a low level of antigen-induced IFN-gamma secretion. We conclude that like full-term infants, most preterm infants are able to mount a specific cellular immune response to the administration of the first doses of an acellular or a whole-cell pertussis vaccine.

Monocyte-derived interleukin-10 depresses the Bordetella pertussis- specific gamma interferon response in vaccinated infants.

Antigen-specific gamma interferon (IFN-gamma) has been demonstrated to participate in protection against Bordetella pertussis infection. Circulating mononuclear cells from B. pertussis-infected and from pertussis-vaccinated infants secrete high amounts of IFN-gamma after in vitro stimulation by B. pertussis antigens, but with a large variation in the secreted IFN-gamma levels between individuals. We show here that the inhibition of the specific IFN-gamma response can be at least partially attributed to IL-10 secretion by monocytes. This IL-10 secretion was not associated with polymorphisms at positions -1082, -819, and -592 of the IL-10 gene promoter, suggesting that other genetic or environmental factors affect IL-10 expression and secretion.

Androgenic 17β-hydroxysteroid dehydrogenase activity of expressed rat type I 3β-hydroxysteroid dehydrogenase/Δ5-Δ4 isomerase

Transient expression in nonsteroidogenic mammalian cells of the rat wild type I and type II 3β-hydroxysteroid dehydrogenase/Δ5-Δ4-isomerase (3β- HSD) cDNAs shows that the encoded proteins, in addition to being able to catalyze the oxidation and isomerization of Δ5-3β-hydroxysteroid precursors into the corresponding Δ4-3-ketosteroids, interconvert 5α- dihydrotestosterone (DHT) and 5α-androstane-3β,17β-diol (3β-diol). When homogenate from cells transfected with a plasmid vector containing type I 3β-HSD is incubated in the presence of DHT using NAD+ as cofactor, a somewhat unexpected metabolite is formed, namely 5α-androstanedione (A- dione), thus indicating an intrinsic androgenic 17β-hydroxysteroid dehydrogenase (17β-HSD) activity of this 3β-HSD isoform. Although the relative Vmax of 17β-HSD activity is 14.9-fold lower than that of 3β-HSD activity, the Km value for the 17β-HSD activity of type I 3β-HSD is 7.97 μM, a value which is in the same range as the conversion of DHT into 3β- diol which shows a Km value of 4.02 μM. Interestingly, this 17β-HSD activity is highly predominant in unbroken cells in culture, thus supporting the physiological relevance of this 'secondary' activity. Such 17β-HSD activity is inhibited by the classical substrates of 3β-HSD, namely pregnenolone (PREG), dehydroepiandrosterone (DHEA), Δ5-androstene-3β,17β- diol (Δ5-diol), 5α-androstane-3β,17β-diol (3β-diol) and DHT, with IC50 values of 2.7, 1.0, 3.2, 6.2, and 6.3 μM, respectively. Although dual enzymatic activities have been previously reported for purified preparations of other steroidogenic enzymes, the present data demonstrate the multifunctional enzymatic activities associated with a recombinant oxidoreductase enzyme. In addition to its well known 3β-HSD activity, this enzyme possesses the ability to catalyze DHT into A-dione thus potentially controlling the level of the active androgen DHT in classical steroidogenic as well as peripheral intracrine tissues.