Comparison of prophylactic and therapeutic use of short-chain fatty acid enemas in diversion colitis: a study in Wistar rats

OBJECTIVES: To study the effect of short-chain fatty-acids on atrophy and inflammation of excluded colonic segments before and after the development of diversion colitis. INTRODUCTION: Diversion colitis is a chronic inflammatory process affecting the dysfunctional colon, possibly evolving with mucous and blood discharge. The most favored hypotheses to explain its development is short-chain fatty-acid deficiency in the colon lumen. METHODS: Wistar rats were submitted to colostomy with distal colon exclusion. Two control groups (A1 and B1) received rectally administered physiological saline, whereas two experimental groups (A2 and B2) received rectally administered short-chain fatty-acids. The A groups were prophylactically treated (5th to 40th days postoperatively), whereas the B groups were therapeutically treated (after post-operative day 40). The mucosal thickness of the excluded colon was measured histologically. The inflammatory reaction of the mucosal lamina propria and the lymphoid tissue response were quantified through established scores. RESULTS: There was a significant thickness recovery of the colonic mucosa in group B2 animals (p = 0.0001), which also exhibited a significant reduction in the number of eosinophilic polymorphonuclear cells in the lamina propria (p = 0.0126) and in the intestinal lumen (p = 0.0256). Group A2 showed no mucosal thickness recovery and significant increases in the numbers of lymphocytes (p = 0.0006) and eosinophilic polymorphonuclear cells in the lamina propria of the mucosa (p = 0.0022). CONCLUSION: Therapeutic use of short-chain fatty-acids significantly reduced eosinophilic polymorphonuclear cell numbers in the intestinal wall and in the colonic lumen; it also reversed the atrophy of the colonic mucosa. Prophylactic use did not impede the development of mucosal atrophy

Medizinischer und gesundheitsökonomischer Nutzen der Untersuchung auf Helicobacter pylori-Besiedlung mittels 13C-Harnstoff-Atemtest in der Primärdiagnostik im Vergleich zu invasiven und nichtinvasiven diagnostischen Verfahren

Hintergrund: Helicobacter pylori (H. pylori) zählt trotz abnehmender Inzidenz zu den häufigsten bakteriellen Infektionskrankheiten des Menschen. Die Infektion mit H. pylori ist ein Risikofaktor für Krankheiten wie gastroduodenale Geschwüre, Magenkarzinomen und MALT (Mucosa Associated Lymphoid Tissue)-Lymphomen. Zur Diagnostik von H. pylori stehen verschiedene invasive und nichtinvasive Verfahren zur Verfügung. Der 13C-Harnstoff-Atemtest wird zur Kontrolle einer Eradikationstherapie empfohlen, kommt in der Primärdiagnostik von H. pylori derzeit jedoch nicht standardmäßig in Deutschland zum Einsatz. Fragestellung: Welchen medizinischen und gesundheitsökonomischen Nutzen hat die Untersuchung auf H. pylori-Besiedlung mittels 13C-Harnstoff-Atemtest in der Primärdiagnostik im Vergleich zu invasiven und nichtinvasiven diagnostischen Verfahren? Methodik: Basierend auf einer systematischen Literaturrecherche in Verbindung mit einer Handsuche werden Studien zur Testgüte und Kosten-Effektivität des 13C-Harnstoff-Atemtests im Vergleich zu anderen diagnostischen Verfahren zum primären Nachweis von H. pylori identifiziert. Es werden nur medizinische Studien eingeschlossen, die den 13C-Harnstoff-Atemtest direkt mit anderen H. pylori-Testverfahren vergleichen. Goldstandard ist eines oder eine Kombination der biopsiebasierten Testverfahren. Für die gesundheitsökonomische Beurteilung werden nur vollständige gesundheitsökonomische Evaluationsstudien einbezogen, bei denen die Kosten-Effektivität des 13C Harnstoff-Atemtests direkt mit anderen H. pylori-Testverfahren verglichen wird. Ergebnisse: Es werden 30 medizinische Studien für den vorliegenden Bericht eingeschlossen. Im Vergleich zum Immunglobulin G (IgG)-Test ist die Sensitivität des 13C-Harnstoff-Atemtests zwölfmal höher, sechsmal niedriger und einmal gleich, und die Spezifität 13-mal höher, dreimal niedriger und zweimal gleich. Im Vergleich zum Stuhl-Antigen-Test ist die Sensitivität des 13C-Harnstoff-Atemtests neunmal höher, dreimal niedriger und einmal gleich, und die Spezifität neunmal höher, zweimal niedriger und zweimal gleich. Im Vergleich zum Urease-Schnelltest sind die Sensitivität des 13C-Harnstoff-Atemtests viermal höher, dreimal niedriger und viermal gleich und die Spezifität fünfmal höher, fünfmal niedriger und einmal gleich. Im Vergleich mit der Histologie ist die Sensitivität des 13C-Harnstoff-Atemtests einmal höher und zweimal niedriger und die Spezifität zweimal höher und einmal niedriger. In je einem Vergleich zeigt sich kein Unterschied zwischen 13C-Harnstoff-Atemtest und 14C-Harnstoff-Atemtest, sowie eine niedrigere Sensitivität und höhere Spezifität im Vergleich zur Polymerase-Kettenreaktion (PCR). Inwieweit die beschriebenen Unterschiede statistisch signifikant sind, wird in sechs der 30 Studien angegeben. Es werden neun gesundheitsökonomische Evaluationen in dem vorliegenden Bericht berücksichtigt. Die Test-and-Treat-Strategie mittels 13C-Harnstoff-Atemtest wird in sechs Studien mit einem Test-and-Treat-Verfahren auf Basis der Serologie sowie in drei Studien mit einem Test-and-Treat-Verfahren auf Basis des Stuhl-Antigen-Tests verglichen. Dabei ist das Atemtestverfahren dreimal kosteneffektiv gegenüber der serologischen Methode und wird von der Stuhl-Antigen-Test-Strategie einmal dominiert. Vier Studien beinhalten einen Vergleich der Test-and -Treat-Strategie auf Basis des 13C-Harnstoff-Atemtests mit einer empirischen antisekretorischen Therapie, wobei sich das Atemtesverfahren zweimal als kosteneffektive Prozedur erweist und zwei Studien einen Vergleich mit einer empirischen Eradikationstherapie. In fünf Studien wird das Test-and-Treat-Verfahren mittels 13C-Harnstoff-Atemtest einer endoskopiebasierten Strategie gegenübergestellt. Zweimal dominiert die Atemteststrategie die endoskopische Prozedur und einmal wird sie von dieser Strategie dominiert. Diskussion:Sowohl die medizinischen als auch die ökonomischen Studien weisen mehr oder minder gravierende Mängel auf und liefern heterogene Ergebnisse. So werden in der Mehrzahl der medizinischen Studien keine Angaben zur statistischen Signifikanz der berichteten Unterschiede zwischen den jeweiligen Testverfahren gemacht. Im direkten Vergleich weist der 13C-Harnstoff-Atemtest überwiegend eine höhere Testgüte als der IgG und der Stuhl-Antigen-Test auf. Aus den Vergleichen mit dem Urease-Schnelltest lassen sich keine Tendenzen bezüglich der Sensitivität ableiten, wohingegen die Spezifität des 13C-Harnstoff-Atemtests höher einzuschätzen ist. Für die Vergleiche des 13C-Harnstoff-Atemtest mit der Histologie, dem 14C-Harnstoff-Atemtest und der PCR liegen zu wenige Ergebnisse vor. In der eingeschlossenen ökonomischen Literatur deuten einige Studienergebnisse auf eine Kosten-Effektivität der Test-and-Treat-Strategie mittels 13C-Harnstoff-Atemtest gegenüber dem Test-and-Treat-Verfahren auf Basis der Serologie und der empirischen antiskretorischen Therapie hin. Um Tendenzen bezüglich der Kosten-Effektivität der Atemteststrategie gegenüber der Test-and-Treat-Strategie mittels Stuhl-Antigen-Test sowie der empirischen Eradikationstherapie abzuleiten, mangelt es an validen Ergebnissen bzw. ökonomischer Evidenz. Die Untersuchungsresultate hinsichtlich eines Vergleichs mit endoskopiebasierten Verfahren fallen diesbezüglich zu heterogen aus. Insgesamt kann keines der ökonomischen Modelle der Komplexität des Managements von Patienten mit dyspeptischen Beschwerden gänzlich gerecht werden. Schlussfolgerungen/Empfehlungen: Zusammenfassend ist festzuhalten, dass die Studienlage zur medizinischen und ökonomischen Beurteilung des 13C-Harnstoff-Atemtests im Vergleich zu anderen diagnostischen Methoden nicht ausreichend ist, um den Atemtest als primärdiagnostisches Standardverfahren im Rahmen einer Test-and-Treat-Strategie beim Management von Patienten mit dyspeptischen Beschwerden für die deutsche Versorgungslandschaft insbesondere vor dem Hintergrund der Leitlinien der Deutschen Gesellschaft für Verdauungs- und Stoffwechselkrankheiten (DGVS) anstelle einer endoskopiebasierten Methode zu empfehlen.

Long-term consequences of Hodgkin lymphoma therapy on T-cell lymphopoiesis

International audience

Factores preditivos de linfoma no síndrome de Sjögren : a propósito de um caso clínico

Trabalho Final do Curso de Mestrado Integrado em Medicina, Faculdade de Medicina, Universidade de Lisboa, 2014

Induction of "tissue" transglutaminase in HIV pathogenesis: evidence for high rate of apoptosis of CD4+ T lymphocytes and accessory cells in lymphoid tissues.

Peripheral blood mononuclear cells and lymphoid tissues from HIV-infected individuals display high levels of "tissue" transglutaminase (tTG) with respect to seronegative persons. In asymptomatic individuals, > 80% of the circulating CD4+ T cells synthesize tTG protein and the number of these cells matches the level of apoptosis detected in the peripheral blood mononuclear cells from the same patients. In HIV-infected lymph nodes tTG protein is localized in large number of cells (macrophages, follicular dendritic cells, and endothelial cells), showing distinctive morphological and biochemical features of apoptosis as well as in lymphocytes and syncytia. These findings demonstrate that during the course of HIV infection, high levels of apoptosis also occur in the accessory cells of lymphoid organs. The increased concentration of epsilon(gamma-glutamyl)lysine isodipeptide, the degradation product of tTG cross-linked proteins, observed in the blood of HIV-infected individuals demonstrates that the enzyme accumulated in the dying cells actively cross-links intracellular proteins. The enhanced levels of epsilon(gamma-glutamyl)lysine in the blood parallels the progression of HIV disease, suggesting that the isodipeptide determination might be a useful method to monitor the in vivo rate of apoptosis.

A transglutaminase from Chinese shrimp (Fenneropenaeus chinensis), full-length cDNA cloning, tissue localization and expression profile after challenge

Transglutaminase can catalyze the cross-linking reaction between soluble clotting protein molecules from the plasma for prevention of excess blood loss from a wound and obstructing micro-organisms from invading the wound in crustaceans. A novel transglutaminase (FcTG) gene was cloned from hemocytes of Chinese shrimp Fenneropenaeus chinensis by 3' and 5' rapid amplification of cDNA ends (RACE) PCR. The full-length cDNA consists of 2972 bp, encoding 757 amino acids with a calculated molecular mass of 84.96 kDa and a theoretical isoelectric point of 5.61. FcTG contains a typical transglutaminase-like homologue (TGc domain: E-value = 1.94e-38). Three catalytic sites (Cys-324, His-391 and Asp-414) are present in this domain. The deduced amino acid sequence of FcTG showed high identity with black tiger shrimp TG, kuruma shrimp TG and crayfish TG. Transcripts of FcTG mRNA were mainly detected in gill, lymphoid organ and hemocytes by RT-PCR. RNA in situ hybridization further confirmed that FcTG was constitutively expressed in hemocytes both in the circulatory system and lymphoid organ. The variation of mRNA transcription level in hemocytes and lymphoid organ following injection of killed bacteria or infection with white spot syndrome virus (WSSV) was quantified by RT-PCR. The up-regulated expression of FcTG in shrimp lymphoid organ following injection of bacteria indicates that it is inducible and might be associated with bacterial challenge. (c) 2006 Elsevier Ltd. All rights reserved.

Characterization of myeloid or lymphoid acute leukemia by a chemiluminescence assay: Comparison with immunocytochemistry using an antimyeloperoxidase antibody

A simple and sensitive chemiluminescence assay for the demonstration of the activity of intracellular myeloperoxidase (MPO) is described, which is useful for the distinction between myeloid and lymphoid commitment in blasts from acute leukemia patients. When the cut-off point was settled at 13 mV of chemiluminescence all cases of acute myeloid leukemia (AML) were distinguished from those of acute lymphoid leukemia. In addition, this technique was able to demonstrate MPO activity in AML poorly differentiated (FAB-M0) which usually does not stain for MPO in classical cytochemistry preparations and could be negative also by immunocytochemistry with anti-MPO monoclonal antibody. Therefore the method here described presented a higher sensitivity than the immunocytochemistry procedure with anti-MPO.

Expression of inducible nitric oxide synthase in macrophages inversely correlates with parasitism of lymphoid tissues in dogs with visceral leishmaniasis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Destruction of lymphoid organ architecture and hepatitis caused by CD4+ T cells

Immune responses have the important function of host defense and protection against pathogens. However, the immune response also causes inflammation and host tissue injury, termed immunopathology. For example, hepatitis B and C virus infection in humans cause immunopathological sequel with destruction of liver cells by the host's own immune response. Similarly, after infection with lymphocytic choriomeningitis virus (LCMV) in mice, the adaptive immune response causes liver cell damage, choriomeningitis and destruction of lymphoid organ architecture. The immunopathological sequel during LCMV infection has been attributed to cytotoxic CD8(+) T cells. However, we now show that during LCMV infection CD4(+) T cells selectively induced the destruction of splenic marginal zone and caused liver cell damage with elevated serum alanin-transferase (ALT) levels. The destruction of the splenic marginal zone by CD4(+) T cells included the reduction of marginal zone B cells, marginal zone macrophages and marginal zone metallophilic macrophages. Functionally, this resulted in an impaired production of neutralizing antibodies against LCMV. Furthermore, CD4(+) T cells reduced B cells with an IgM(high)IgD(low) phenotype (transitional stage 1 and 2, marginal zone B cells), whereas other B cell subtypes such as follicular type 1 and 2 and germinal center/memory B cells were not affected. Adoptive transfer of CD4(+) T cells lacking different important effector cytokines and cytolytic pathways such as IFNγ, TNFα, perforin and Fas-FasL interaction did reveal that these cytolytic pathways are redundant in the induction of immunopathological sequel in spleen. In conclusion, our results define an important role of CD4(+) T cells in the induction of immunopathology in liver and spleen. This includes the CD4(+) T cell mediated destruction of the splenic marginal zone with consecutively impaired protective neutralizing antibody responses.

Epithelial-intrinsic IKKα expression regulates group 3 innate lymphoid cell responses and antibacterial immunity

Innate lymphoid cells (ILCs) are critical for maintaining epithelial barrier integrity at mucosal surfaces; however, the tissue-specific factors that regulate ILC responses remain poorly characterized. Using mice with intestinal epithelial cell (IEC)-specific deletions in either inhibitor of κB kinase (IKK)α or IKKβ, two critical regulators of NFκB activation, we demonstrate that IEC-intrinsic IKKα expression selectively regulates group 3 ILC (ILC3)-dependent antibacterial immunity in the intestine. Although IKKβ(ΔIEC) mice efficiently controlled Citrobacter rodentium infection, IKKα(ΔIEC) mice exhibited severe intestinal inflammation, increased bacterial dissemination to peripheral organs, and increased host mortality. Consistent with weakened innate immunity to C. rodentium, IKKα(ΔIEC) mice displayed impaired IL-22 production by RORγt(+) ILC3s, and therapeutic delivery of rIL-22 or transfer of sort-purified IL-22-competent ILCs from control mice could protect IKKα(ΔIEC) mice from C. rodentium-induced morbidity. Defective ILC3 responses in IKKα(ΔIEC) mice were associated with overproduction of thymic stromal lymphopoietin (TSLP) by IECs, which negatively regulated IL-22 production by ILC3s and impaired innate immunity to C. rodentium. IEC-intrinsic IKKα expression was similarly critical for regulation of intestinal inflammation after chemically induced intestinal damage and colitis. Collectively, these data identify a previously unrecognized role for epithelial cell-intrinsic IKKα expression and TSLP in regulating ILC3 responses required to maintain intestinal barrier immunity.

IL-33 promotes an innate immune pathway of intestinal tissue protection dependent on amphiregulin-EGFR interactions

The barrier surfaces of the skin, lung, and intestine are constantly exposed to environmental stimuli that can result in inflammation and tissue damage. Interleukin (IL)-33-dependent group 2 innate lymphoid cells (ILC2s) are enriched at barrier surfaces and have been implicated in promoting inflammation; however, the mechanisms underlying the tissue-protective roles of IL-33 or ILC2s at surfaces such as the intestine remain poorly defined. Here we demonstrate that, following activation with IL-33, expression of the growth factor amphiregulin (AREG) is a dominant functional signature of gut-associated ILC2s. In the context of a murine model of intestinal damage and inflammation, the frequency and number of AREG-expressing ILC2s increases following intestinal injury and genetic disruption of the endogenous AREG-epidermal growth factor receptor (EGFR) pathway exacerbated disease. Administration of exogenous AREG limited intestinal inflammation and decreased disease severity in both lymphocyte-sufficient and lymphocyte-deficient mice, revealing a previously unrecognized innate immune mechanism of intestinal tissue protection. Furthermore, treatment with IL-33 or transfer of ILC2s ameliorated intestinal disease severity in an AREG-dependent manner. Collectively, these data reveal a critical feedback loop in which cytokine cues from damaged epithelia activate innate immune cells to express growth factors essential for ILC-dependent restoration of epithelial barrier function and maintenance of tissue homeostasis.

Association of Smads with lymphoid enhancer binding factor 1/T cell-specific factor mediates cooperative signaling by the transforming growth factor-β and Wnt pathways

The transforming growth factor-β (TGFβ) and Wnt/wingless pathways play pivotal roles in tissue specification during development. Activation of Smads, the effectors of TGFβ superfamily signals, results in Smad translocation from the cytoplasm into the nucleus where they act as transcriptional comodulators to regulate target gene expression. Wnt/wingless signals are mediated by the DNA-binding HMG box transcription factors lymphoid enhancer binding factor 1/T cell-specific factor (LEF1/TCF) and their coactivator β-catenin. Herein, we show that Smad3 physically interacts with the HMG box domain of LEF1 and that TGFβ and Wnt pathways synergize to activate transcription of the Xenopus homeobox gene twin (Xtwn). Disruption of specific Smad and LEF1/TCF DNA-binding sites in the promoter abrogates synergistic activation of the promoter. Consistent with this observation, introduction of Smad sites into a TGFβ-insensitive LEF1/TCF target gene confers cooperative TGFβ and Wnt responsiveness to the promoter. Furthermore, we demonstrate that TGFβ-dependent activation of LEF1/TCF target genes can occur in the absence of β-catenin binding to LEF1/TCF and requires both Smad and LEF1/TCF DNA-binding sites in the Xtwn promoter. Thus, our results show that TGFβ and Wnt signaling pathways can independently or cooperatively regulate LEF1/TCF target genes and suggest a model for how these pathways can synergistically activate target genes.

cDNA structure, tissue distribution, and chromosomal localization of rat PC7, a novel mammalian proprotein convertase closest to yeast kexin-like proteinases.

By using reverse transcription-coupled PCR on rat anterior pituitary RNA, we isolated a 285-bp cDNA coding for a novel subtilisin/kexin-like protein convertase (PC), called rat (r) PC7. By screening rat spleen and PC12 cell lambda gt11 cDNA libraries, we obtained a composite 3.5-kb full-length cDNA sequence of rPC7. The open reading frame codes for a prepro-PC with a 36-amino acid signal peptide, a 104-amino acid prosegment ending with a cleavable RAKR sequence, and a 747-amino acid type I membrane-bound glycoprotein, representing the mature form of this serine proteinase. Phylogenetic analysis suggests that PC7 represents the most divergent enzyme of the mammalian convertase family and that it is the closest member to the yeast convertases krp and kexin. Northern blot analyses demonstrated a widespread expression with the richest source of rPC7 mRNA being the colon and lymphoid-associated tissues. In situ hybridization revealed a distinctive tissue distribution that sometimes overlaps with that of furin, suggesting that PC7 has widespread proteolytic functions. The gene for PC7 (Pcsk7) was mapped to mouse chromosome 9 by linkage analysis of an interspecific backcross DNA panel.

Lymphoid aggregates that resemble tertiary lymphoid organs define a specific pathological subset in metal-on-metal hip replacements

Aseptic lymphocyte-dominated vasculitis-associated lesion (ALVAL) has been used to describe the histological lesion associated with metal-on-metal (M-M) bearings. We tested the hypothesis that the lymphoid aggregates, associated with ALVAL lesions resemble tertiary lymphoid organs (TLOs). Histopathological changes were examined in the periprosthetic tissue of 62 M-M hip replacements requiring revision surgery, with particular emphasis on the characteristics and pattern of the lymphocytic infiltrate. Immunofluorescence and immunohistochemistry were used to study the classical features of TLOs in cases where large organized lymphoid follicles were present. Synchrotron X-ray fluorescence (XRF) measurements were undertaken to detect localisation of implant derived ions/particles within the samples. Based on type of lymphocytic infiltrates, three different categories were recognised; diffuse aggregates (51%), T cell aggregates (20%), and organised lymphoid aggregates (29%). Further investigation of tissues with organised lymphoid aggregates showed that these tissues recapitulate many of the features of TLOs with T cells and B cells organised into discrete areas, the presence of follicular dendritic cells, acquisition of high endothelial venule like phenotype by blood vessels, expression of lymphoid chemokines and the presence of plasma cells. Co-localisation of implant-derived metals with lymphoid aggregates was observed. These findings suggest that in addition to the well described general foreign body reaction mediated by macrophages and a T cell mediated type IV hypersensitivity response, an under-recognized immunological reaction to metal wear debris involving B cells and the formation of tertiary lymphoid organs occurs in a distinct subset of patients with M-M implants. © 2013 Mittal et al.