Effect of iron therapy on platelet counts in patients with inflammatory bowel disease-associated anemia

Background and Aims

Secondary thrombocytosis is a clinical feature of unknown significance. In inflammatory bowel disease (IBD), thrombocytosis is considered a marker of active disease; however, iron deficiency itself may trigger platelet generation. In this study we tested the effect of iron therapy on platelet counts in patients with IBD-associated anemia.

Methods

Platelet counts were analyzed before and after iron therapy from four prospective clinical trials. Further, changes in hemoglobin, transferrin saturation, ferritin, C-reactive protein, and leukocyte counts, before and after iron therapy were compared. In a subgroup the effect of erythropoietin treatment was tested. The results were confirmed in a large independent cohort (FERGIcor).

Results

A total of 308 patient records were available for the initial analysis. A dose-depended drop in platelet counts (mean 425 G/L to 320 G/L; p<0.001) was found regardless of the type of iron preparation (iron sulphate, iron sucrose, or ferric carboxymaltose). Concomitant erythropoietin therapy as well as parameters of inflammation (leukocyte counts, C-reactive protein) had no effect on the change in platelet counts. This effect of iron therapy on platelets was confirmed in the FERGIcor study cohort (n=448, mean platelet counts before iron therapy: 383 G/L, after: 310 G/L, p<0.001).

Conclusion

Iron therapy normalizes elevated platelet counts in patients with IBD-associated anemia. Thus, iron deficiency is an important pathogenetic mechanism of secondary thrombocytosis in IBD.     

p38 mitogen-activated protein kinase is activated and linked to TNF-alpha signaling in inflammatory bowel disease

Inflammatory bowel diseases (IBD)--Crohn's disease and ulcerative colitis--are relapsing chronic inflammatory disorders which involve genetic, immunological, and environmental factors. The regulation of TNF-alpha, a key mediator in the inflammatory process in IBD, is interconnected with mitogen-activated protein kinase pathways. The aim of this study was to characterize the activity and expression of the four p38 subtypes (p38alpha-delta), c-Jun N-terminal kinases (JNKs), and the extracellular signal-regulated kinases (ERK)1/2 in the inflamed intestinal mucosa. Western blot analysis revealed that p38alpha, JNKs, and ERK1/2 were significantly activated in IBD, with p38alpha showing the most pronounced increase in kinase activity. Protein expression of p38 and JNK was only moderately altered in IBD patients compared with normal controls, whereas ERK1/2 protein was significantly down-regulated. Immunohistochemical analysis of inflamed mucosal biopsies localized the main expression of p38alpha to lamina propria macrophages and neutrophils. ELISA screening of the supernatants of Crohn's disease mucosal biopsy cultures showed that incubation with the p38 inhibitor SB 203580 significantly reduced secretion of TNF-alpha. In vivo inhibition of TNF-alpha by a single infusion of anti-TNF-alpha Ab (infliximab) resulted in a highly significant transient increase of p38alpha activity during the first 48 h after infusion. A significant infliximab-dependent p38alpha activation was also observed in THP-1 myelomonocytic cells. In human monocytes, infliximab enhanced TNF-alpha gene expression, which could be inhibited by SB 203580. In conclusion, p38alpha signaling is involved in the pathophysiology of IBD.     

Microbiota dysbiosis and barrier dysfunction in inflammatory bowel disease and colorectal cancers: exploring a common ground hypothesis

Inflammatory bowel disease (IBD) is a multifactorial disease which arises as a result of the interaction of genetic, environmental, barrier and microbial factors leading to chronic inflammation in the intestine. Patients with IBD had a higher risk of developing colorectal carcinoma (CRC), of which the subset was classified as colitis-associated cancers. Genetic polymorphism of innate immune receptors had long been considered a major risk factor for IBD, and the mutations were also recently observed in CRC. Altered microbial composition (termed microbiota dybiosis) and dysfunctional gut barrier manifested by epithelial hyperpermeability and high amount of mucosa-associated bacteria were observed in IBD and CRC patients. The findings suggested that aberrant immune responses to penetrating commensal microbes may play key roles in fueling disease progression. Accumulative evidence demonstrated that mucosa-associated bacteria harbored colitogenic and protumoral properties in experimental models, supporting an active role of bacteria as pathobionts (commensal-derived opportunistic pathogens). Nevertheless, the host factors involved in bacterial dysbiosis and conversion mechanisms from lumen-dwelling commensals to mucosal pathobionts remain unclear. Based on the observation of gut leakiness in patients and the evidence of epithelial hyperpermeability prior to the onset of mucosal histopathology in colitic animals, it was postulated that the epithelial barrier dysfunction associated with mucosal enrichment of specific bacterial strains may predispose the shift to disease-associated microbiota. The speculation of leaky gut as an initiating factor for microbiota dysbiosis that eventually led to pathological consequences was proposed as the “common ground hypothesis”, which will be highlighted in this review. Overall, the understanding of the core interplay between gut microbiota and epithelial barriers at early subclinical phases will shed light to novel therapeutic strategies to manage chronic inflammatory disorders and colitis-associated cancers.     

The host inflammatory response contributes to disease severity in Crimean-Congo hemorrhagic fever virus infected mice

Crimean-Congo hemorrhagic fever virus (CCHFV) is an important human pathogen. In cell culture, CCHFV is sensed by the cytoplasmic RNA sensor retinoic acid-inducible gene I (RIG-I) molecule and its adaptor molecule mitochondrial antiviral signaling (MAVS) protein. MAVS initiates both type I interferon (IFN-I) and proinflammatory responses. Here, we studied the role MAVS plays in CCHFV infection in mice in both the presence and absence of IFN-I activity. MAVS-deficient mice were not susceptible to CCHFV infection when IFN-I signaling was active and showed no signs of disease. When IFN-I signaling was blocked by antibody, MAVS-deficient mice lost significant weight, but were uniformly protected from lethal disease, whereas all control mice succumbed to infection. Cytokine activity in the infected MAVS-deficient mice was markedly blunted. Subsequent investigation revealed that CCHFV infected mice lacking TNF-α receptor signaling (TNFA-R-deficient), but not IL-6 or IL-1 activity, had more limited liver injury and were largely protected from lethal outcomes. Treatment of mice with an anti-TNF-α neutralizing antibody also conferred partial protection in a post-virus exposure setting. Additionally, we found that a disease causing, but non-lethal strain of CCHFV produced more blunted inflammatory cytokine responses compared to a lethal strain in mice. Our work reveals that MAVS activation and cytokine production both contribute to CCHFV pathogenesis, potentially identifying new therapeutic targets to treat this disease.     

Helicobacter-induced inflammatory bowel disease in IL-10- and T cell-deficient mice

Inflammatory bowel disease (IBD) is thought to result from a dysregulated mucosal immune response to luminal microbial antigens, with T lymphocytes mediating the colonic pathology. Infection with Helicobacter spp has been reported to cause IBD in immunodeficient mice, some of which lack T lymphocytes. To further understand the role of T cells and microbial antigens in triggering IBD, we infected interleukin (IL)-10(-/-), recombinase-activating gene (Rag)1(-/-), T-cell receptor (TCR)-alpha(-/-), TCR-beta(-/-), and wild-type mice with Helicobacter hepaticus or Helicobacter bilis and compared the histopathological IBD phenotype. IL-10(-/-) mice developed severe diffuse IBD with either H. bilis or H. hepaticus, whereas Rag1(-/-), TCR-alpha(-/-), TCR-beta(-/-), and wild-type mice showed different susceptibilities to Helicobacter spp infection. Proinflammatory cytokine mRNA expression was increased in the colons of Helicobacter-infected IL-10(-/-) and TCR-alpha(-/-) mice with IBD. These results confirm and extend the role of Helicobacter as a useful tool for investigating microbial-induced IBD and show the importance, but not strict dependence, of T cells in the development of bacterial-induced IBD.     

Pneumonia due to mycoplasma in gnotobiotic mice. II. Localization of Mycoplasma pulmonis in the lungs of infected gnotobiotic mice by electron microscopy

Organick, Avrum B. (Marquette University School of Medicine, Milwaukee, Wis.), Kenneth A. Siegesmund, and Irving I. Lutsky. Pneumonia due to mycoplasma in gnotobiotic mice. II. Localization of Mycoplasma pulmonis in the lungs of infected gnotobiotic mice by electron microscopy. J. Bacteriol. 92:1164-1176. 1966.-Lesions in lungs of gnotobiotic mice inoculated intranasally with Mycoplasma pulmonis were examined by electron microscopy after osmic acid fixation. At 1 week after infection, mycoplasma cells were found in large numbers in the bronchi at the surface of bronchial epithelial cells and, in smaller numbers, in the alveoli where active phagocytosis by polymorphonuclear leukocytes (PMN) occurred. Cytopathic changes in underlying bronchial epithelial cells, not apparent by light microscopy, were observed. At 3 weeks after infection, mycoplasma cells were rarely seen in the bronchi, and were no longer seen free in the alveolar spaces or within PMN. Lungs examined after glutaraldehyde fixation 1 week after infection confirmed the presence of mycoplasma cells in the alveolar spaces and within phagocytic vacuoles of PMN, but also revealed numerous ring forms within granular pneumocytes. These forms seemed to represent intracytoplasmic developmental stages of M. pulmonis, in which elementary bodies appeared in large numbers.     

A spontaneous mutation of the rat Themis gene leads to impaired function of regulatory T cells linked to inflammatory bowel disease

Spontaneous or chemically induced germline mutations, which lead to Mendelian phenotypes, are powerful tools to discover new genes and their functions. Here, we report an autosomal recessive mutation that occurred spontaneously in a Brown-Norway (BN) rat colony and was identified as causing marked T cell lymphopenia. This mutation was stabilized in a new rat strain, named BN(m) for "BN mutated." In BN(m) rats, we found that the T cell lymphopenia originated in the thymus, was intrinsic to CD4 T lymphocytes, and was associated with the development of an inflammatory bowel disease. Furthermore, we demonstrate that the suppressive activity of both peripheral and thymic CD4(+) CD25(bright) regulatory T cells (Treg) is defective in BN(m) rats. Complementation of mutant animals with BN Treg decreases disease incidence and severity, thus suggesting that the impaired Treg function is involved in the development of inflammatory bowel disease in BN(m) rats. Moreover, the cytokine profile of effector CD4 T cells is skewed toward Th2 and Th17 phenotypes in BN(m) rats. Linkage analysis and genetic dissection of the CD4 T cell lymphopenia in rats issued from BN(m)×DA crosses allowed the localization of the mutation on chromosome 1, within a 1.5 megabase interval. Gene expression and sequencing studies identified a frameshift mutation caused by a four-nucleotide insertion in the Themis gene, leading to its disruption. This result is the first to link Themis to the suppressive function of Treg and to suggest that, in Themis-deficient animals, defect of this function is involved in intestinal inflammation. Thus, this study highlights the importance of Themis as a new target gene that could participate in the pathogenesis of immune diseases characterized by chronic inflammation resulting from a defect in the Treg compartment.     

发酵乳杆菌AR497改善DSS诱导的小鼠炎症性肠病

本实验主要探究发酵乳杆菌AR497对DSS诱导的小鼠炎症性肠病的影响。发酵乳杆菌AR497在低pH、高胆盐浓度、高渗透压等极端条件下仍具有良好的生长能力,对大部分抗生素敏感;在C57BL/6J小鼠中研究其对由葡聚糖硫酸钠(DSS)诱导的结肠炎的缓解作用,发酵乳杆菌AR497处理后抑制小鼠体重减少,降低疾病活动指数,上调紧密连接蛋白基因Claudin 3,ZO-1和E-cadherin 1的表达。实验结果表明发酵乳杆菌AR497具有优良的生物学特性并可通过保护肠道屏障从而缓解DSS诱导的结肠炎。     

Electroacupuncture inhibits visceral pain via adenosine receptors in mice with inflammatory bowel disease

Purinergic Signalling - To investigate the involvement of peripheral adenosine receptors in the effect of electroacupuncture (EA) on visceral pain in mice with inflammatory bowel disease (IBD)....     

Sensitivity to MPTP is not increased in Parkinson's disease-associated mutant alpha-synuclein transgenic mice

Environmental and genetic factors that contribute to the pathogenesis of Parkinson's disease are discussed. Mutations in the alpha-synuclein (alphaSYN ) gene are associated with rare cases of autosomal-dominant Parkinson's disease. We have analysed the dopaminergic system in transgenic mouse lines that expressed mutant [A30P]alphaSYN under the control of a neurone-specific Thy-1 or a tyrosine hydroxylase (TH) promoter. The latter mice showed somal and neuritic accumulation of transgenic [A30P]alphaSYN in TH-positive neurones in the substantia nigra. However, there was no difference in the number of TH-positive neurones in the substantia nigra and the concentrations of catecholamines in the striatum between these transgenic mice and non-transgenic littermates. To investigate whether forced expression of [A30P]alphaSYN increased the sensitivity to putative environmental factors we subjected transgenic mice to a chronic 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) regimen. The MPTP-induced decrease in the number of TH-positive neurones in the substantia nigra and the concentrations of catecholamines in the striatum did not differ in any of the [A30P]alphaSYN transgenic mouse lines compared with wild-type controls. These results suggest that mutations and forced expression of alphaSYN are not likely to increase the susceptibility to environmental toxins in vivo.     

Biomarker-responsive engineered probiotic diagnoses,records, and ameliorates inflammatory bowel disease in mice

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Helicobacter hepaticus infection triggers inflammatory bowel disease in T cell receptor alphabeta mutant mice

The T cell receptor alpha chain-deficient (TCR alpha-/-) and TCR beta chain-deficient (TCR beta-/-) mice develop chronic intestinal inflammation that resembles inflammatory bowel disease by 3 to 4 months of age. The objective of the study reported here was to determine the role of infection with the bacterial pathogen Helicobacter hepaticus in the pathogenesis of disease in TCR alphabeta mutant mice. The H. hepaticus-infected TCR alphabeta mutant mice were rederived by use of embryo transfer to produce Helicobacter-free animals. Helicobacter-free TCR alpha-/-, TCR beta-/-, and TCR alpha-/- beta-/- mice were inoculated with H. hepaticus. Experimentally infected mice and uninfected control mice were examined for intestinal lesions at 3, 6, and 9 months after inoculation. The TCR alphabeta mutant mice inoculated with H. hepaticus developed intestinal epithelial cell hyperplasia and mucosal inflammation. By 6 months after inoculation, infected animals had moderate cecal and colonic lesions. Helicobacter-free TCR alpha-/- mice, but not TCR beta-/- or TCR alpha-/- x beta-/- mice, also developed H. hepaticus-independent colitis by 9 months after inoculation. Infection with H. hepaticus is sufficient to cause chronic proliferative intestinal inflammation in TCR alphabeta mutant mice. However, H. hepaticus infection is not necessary for intestinal disease in TCR alpha-/- mice.     

Behaviour and physiology are linked in the responses of freshwater mussels to drought

1. Droughts have become prevalent in the south‐eastern U.S.A. and are predicted to become more common in the future. Drought conditions have particularly strong negative effects on sessile aquatic organisms with limited dispersal ability. This study explored the linkages between physiological tolerance, behavioural response and survival of three species of freshwater mussels subjected to drought. 2. To assess physiological tolerance, we measured survival under desiccation at 25, 35 and 45 °C in the laboratory. To assess behavioural responses, we tracked horizontal and vertical movement of mussels in a drying stream reach. 3. Uniomerus tetralasmus showed the greatest desiccation tolerance, Lampsilis straminea was intermediate, and Pyganodon grandis had the lowest tolerance at all temperatures. 4. In the drying stream reach, U. tetralasmus showed little horizontal movement and quickly became stranded. The other two species tracked the receding water. It was not until the pool had been reduced to c. 10% of its original size that ≥50% of P. grandis and L. straminea became stranded. 5. Uniomerus tetralasmus and L. straminea burrowed in response to becoming stranded; however, both species burrowed only shallowly (3–4 cm), presumably because burrowing to greater depths did not convey increasing thermal refuge. Pyganodon grandis rarely burrowed. No P. grandis survived the 15‐week drought, while 45% of L. straminea and 77% of U. tetralasmus survived. 6. Three strategies emerged for freshwater mussels to cope with drought conditions: tracking (intolerant), track then burrow (semi‐tolerant) and burrowing (tolerant). Results suggest that drought poses the greatest threat to intolerant trackers, while tolerant burrowers are the most resistant to drought conditions.     

Loss of Setd2 associates with aberrant microRNA expression and contributes to inflammatory bowel disease progression in mice

Both SETD2-mediated H3K36me3 and miRNAs play critical epigenetic roles in inflammatory bowel disease (IBD) and involve in the dysfunctional intestinal barrier. However, little is known about cross-talk between these two types of regulators in IBD progression. We performed small RNA sequencing of Setd2 epithelium-specific knockout mice (Setd2^Vil-KO) and wild-type controls, both with DSS-induced colitis, and designed a framework for integrative analysis. Firstly, we integrated the downloaded ChIP-seq data with miRNA expression profiles and identified a significant intersection of pre-miRNA expression and H3K36me3 modification. A significant inverse correlation was detected between changes of H3K36me3 modification and expression of the 171 peak-covered miRNAs. We further integrated RNA-seq data with predicted miRNA targets to screen negatively regulated miRNA-mRNA pairs and found the H3K36me3-associated differentially expressed microRNAs significantly enriched in cell-cell junction and signaling pathways. Using network analysis, we identified ten hub miRNAs, among which six are H3K36me3-associated, suggesting therapeutic targets for IBD patients with SETD2-deficiency.     

High-throughput clone library analysis of the mucosa-associated microbiota reveals dysbiosis and differences between inflamed and non-inflamed regions of the intestine in inflammatory bowel disease

Background  

The gut microbiota is thought to play a key role in the development of the inflammatory bowel diseases Crohn's disease (CD) and ulcerative colitis (UC). Shifts in the composition of resident bacteria have been postulated to drive the chronic inflammation seen in both diseases (the "dysbiosis" hypothesis). We therefore specifically sought to compare the mucosa-associated microbiota from both inflamed and non-inflamed sites of the colon in CD and UC patients to that from non-IBD controls and to detect disease-specific profiles.     

不同途径下MIMP对炎症性肠病小鼠的肠屏障及炎症因子的改善作用

目的通过葡聚糖硫酸钠(DSS)诱导小鼠炎症性肠病(inflammatory bowel disease,IBD)模型并观察不同途经下乳酸杆菌微小膜蛋白(MIMP)对炎症性肠病小鼠的肠炎的影响。方法 C57BL/6小鼠40只根据DSS和MIMP不同的干预组合将其分为4组:诱导肠炎+MIMP腹腔注射组(n=10)、诱导肠炎+MIMP灌胃组(n=10)、单纯诱导肠炎组(n=10)、空白对照组(n=10),DSS干预浓度为2.5%。干预期间,观察小鼠体重变化情况,腹泻、血便、死亡等发生率,各组小鼠活体肠道通透性差异,比较肠道长度及肠上皮组织病理学改变,应用荧光定量PCR反应观察各组小鼠肠道中的炎症因子的表达,应用免疫组织化学染色观察各组小鼠肠道上皮中IL-23的表达。结果 MIMP腹腔注射组以及灌胃组小鼠整体情况较好,体重减轻程度轻,腹泻、便血及死亡发生率低;MIMP干预可显著改善肠道通透性(P0.05),并降低肠道萎缩程度,同时降低小鼠肠道病理评分及组织学评分,可显著降低小鼠肠道中促炎性细胞因子(IL-23p19、IL-17A、IL-12p40)的表达(P0.05),并提高抑炎性细胞因子(IL-10)的表达(P0.05),免疫组化显示MIMP可显著降低小鼠肠上皮细胞中IL-23的表达水平。结论 MIMP腹腔注射及灌胃对IBD小鼠的炎症状态及肠道屏障功能有显著的改善作用,并可显著降低促炎性细胞因子的表达,提高抑炎性细胞因子的表达。