Tir Triggers Expression of CXCL1 in Enterocytes and Neutrophil Recruitment during Citrobacter rodentium Infection

The hallmarks of enteropathogenic Escherichia coli (EPEC) infection are formation of attaching and effacing (A/E) lesions on mucosal surfaces and actin-rich pedestals on cultured cells, both of which are dependent on the type III secretion system effector Tir. Following translocation into cultured cells and clustering by intimin, Tir Y474 is phosphorylated, leading to recruitment of Nck, activation of N-WASP, and actin polymerization via the Arp2/3 complex. A secondary, weak, actin polymerization pathway is triggered via an NPY motif (Y454). Importantly, Y454 and Y474 play no role in A/E lesion formation on mucosal surfaces following infection with the EPEC-like mouse pathogen Citrobacter rodentium. In this study, we investigated the roles of Tir segments located upstream of Y451 and downstream of Y471 in C. rodentium colonization and A/E lesion formation. We also tested the role that Tir residues Y451 and Y471 play in host immune responses to C. rodentium infection. We found that deletion of amino acids 382 to 462 or 478 to 547 had no impact on the ability of Tir to mediate A/E lesion formation, although deletion of amino acids 478 to 547 affected Tir translocation. Examination of enterocytes isolated from infected mice revealed that a C. rodentium strain expressing Tir_Y451A/Y471A recruited significantly fewer neutrophils to the colon and triggered less colonic hyperplasia on day 14 postinfection than the wild-type strain. Consistently, enterocytes isolated from mice infected with C. rodentium expressing Tir_Y451A/Y471A expressed significantly less CXCL1. These result show that Tir-induced actin remodeling plays a direct role in modulation of immune responses to C. rodentium infection.     

APOBEC3 enzymes restrict marginal zone B cells

In general, a long‐lasting immune response to viruses is achieved when they are infectious and replication competent. In the mouse, the neutralizing antibody response to Friend murine leukemia virus is contributed by an allelic form of the enzyme Apobec3 (abbreviated A3). This is counterintuitive because A3 directly controls viremia before the onset of adaptive antiviral immune responses. It suggests that A3 also affects the antibody response directly. Here, we studied the relative size of cell populations of the adaptive immune system as a function of A3 activity. We created a transgenic mouse that expresses all seven human A3 enzymes and compared it to WT and mouse A3‐deficient mice. A3 enzymes decreased the number of marginal zone B cells, but not the number of follicular B or T cells. When mouse A3 was knocked out, the retroelement hitchhiker‐1 and sialyl transferases encoded by genes close to it were overexpressed three and two orders of magnitude, respectively. We suggest that A3 shifts the balance, from the fast antibody response mediated by marginal zone B cells with little affinity maturation, to a more sustained germinal center B‐cell response, which drives affinity maturation and, thereby, a better neutralizing response.     

Effect of Helicobacter pylori eradication in Iranian patients with functional dyspepsia: a prospective,randomized, placebo-controlled trial

Introduction

Whether patients with functional dyspepsia (FD) should receive Helicobacter pylori (H. pylori) eradication therapy remains controversial. The objective of this trial was to evaluate the effect of H. pylori eradication therapy on dyspeptic symptoms of patients with FD.

Material and methods

A prospective, randomized, placebo-controlled trial of H. pylori eradication for FD was conducted. A total of 720 FD patients diagnosed by Rome III criteria were consecutively enrolled. We randomly assigned 186 H. pylori infected patients with FD to receive quadruple therapy for 14 days and 173 such patients to receive identical-appearing placebos. Severity of abdominal symptoms was assessed with the Glasgow Dyspepsia Severity Score (GDSS), and eradication of H. pylori by ¹³C-urea breath test was evaluated during one year.

Results

The rate of eradication of H. pylori infection was 87.1% in the treatment group and 2.9% in the placebo group at 6 weeks (p = 0.001). The mean GDSS at 12 months was 4.9 ±2.8 in the treatment group, as compared to 5.2 ±3.4 in the placebo group (p = 0.064). The scores in both groups were lower than those at baseline. According to the intention-to-treat analysis, at 12 months, there was no significant difference between groups in the rate of successful treatment (48.6% in the treatment group and 51.2% in the placebo group; p = 0.84). There was no significant difference in mean symptom scores between the two treatment groups at any point during follow-up.

Conclusions

The results of our study provide no evidence that H. pylori eradication leads to relief of symptoms 12 months after treatment, and there is a need for further studies.     

Normative Values for Corneal Nerve Morphology Assessed Using Corneal Confocal Microscopy: A Multinational Normative Data Set

OBJECTIVECorneal confocal microscopy is a novel diagnostic technique for the detection of nerve damage and repair in a range of peripheral neuropathies, in particular diabetic neuropathy. Normative reference values are required to enable clinical translation and wider use of this technique. We have therefore undertaken a multicenter collaboration to provide worldwide age-adjusted normative values of corneal nerve fiber parameters.RESULTSThere was a significant linear age-dependent decrease in CNFD (−0.164 no./mm² per year for men, P < 0.01, and −0.161 no./mm² per year for women, P < 0.01). There was no change with age in CNBD (0.192 no./mm² per year for men, P = 0.26, and −0.050 no./mm² per year for women, P = 0.78). CNFL decreased in men (−0.045 mm/mm² per year, P = 0.07) and women (−0.060 mm/mm² per year, P = 0.02). CNFT increased with age in men (0.044 per year, P < 0.01) and women (0.046 per year, P < 0.01). Height, weight, and BMI did not influence the 5th percentile normative values for any corneal nerve parameter.CONCLUSIONSThis study provides robust worldwide normative reference values for corneal nerve parameters to be used in research and clinical practice in the study of diabetic and other peripheral neuropathies.     

Non‐total body irradiation myeloablative conditioning with intravenous busulfan and cyclophosphamide in hematopoietic stem cell transplantation for malignant infantile osteopetrosis

HSCT is the only curative treatment for MIOP. We prospectively investigated the outcome of HSCT using intravenous busulfan‐based conditioning regimen from 2008 to 2013. Nineteen patients (median age = 17 months) underwent transplantation from HLA‐matched related donors (n = 14), HLA‐haploidentical related donors (n = 2), partially matched cord blood donors (n = 2), and HLA‐matched unrelated donor (n = 1). Bone marrow (n = 9), peripheral blood (n = 8), and cord blood (n = 2) were used as stem cell sources. All but one patient demonstrated primary engraftment. Two patients experienced secondary graft failure. During the follow‐up period, three patients showed mixed chimerism (45%, 45%, and 70% of donor cells were engrafted in each one of these patients) but are disease free. Two‐yr OS and DFS were 84.2% and 73.7%, respectively. Improvement of visual acuity and partial reversal of mild conductive hearing loss occurred in two and four patients, respectively. The causes of death among three patients were infection, GvHD, and disease progression. In conclusion, due to major side effects of MIOP such as visual and hearing loss, early treatment using myeloablative conditioning without irradiation HSCT is suggested. The use of an HLA‐matched related donor seems to be highly successful in this regard. Also, according to results of our study, mixed chimerism may be sufficient to resolve symptoms of disease.     

alpha-globin gene deletion and point mutation analysis among in Iranian patients with microcytic hypochromic anemia

We tested 67 Iranian individuals, presenting with low mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH) levels, normal hemoglobin electrophoresis and iron status, for the presence of twelve common alpha-thalassemia gene deletions and point mutations. Five different mutations (-alpha(3.7), -alpha(4.2), --MED, -(alpha)20.5, Hb Constant Spring) were identified in a total of 43 cases     

Gestational diabetes in Iran: incidence, risk factors and pregnancy outcomes

The objective of this study was to determine the incidence of gestational diabetes mellitus (GDM) and compare fetal, maternal and neonatal complications amongst women with GDM and pregnant women with normal glucose tolerance in an urban Iranian population. In a prospective cohort study, universal screening for gestational diabetes mellitus was performed for 1310 pregnant women who were referred from private clinics and community health care centers to Fatemiyeh Hospital in Shahrood City. Screening was performed with a 50 g oral Glucose Challenge Test (GCT) with 130 mg/dl cut-off point, then a diagnostic 100 g Oral Glucose Tolerance Test (OGTT) was done according to Carpenter and Coustan criteria. The incidence of GDM was 4.8%. There were differences in risk factors: age >30 years, family history of diabetes, obesity, previous macrosomia, glycosuria between the two groups (P<0.001). Women with GDM had a higher rate of stillbirth (P<0.001; odds ratio 17.1, 95% CI=4.5-65.5), hydramnios (P<0.001; odds ratio 15.5, 95% CI=4.8-50.5), gestational hypertension (P<0.001; odds ratio 6, 95% CI=2.3-15.3), macrosomia (P<0.05; odds ratio 3.2, 95% CI=1.2-8.6) and caesarean section (P<0.001). We have found that the incidence of GDM in an urban Iranian population is similar to developed countries. Complications were more common in the GDM group than in the normal group and outcomes for women with persistent diabetes post-partum were particularly poor. We recommend screening for GDM in Iran, but further evaluation of selective screening and cost effectiveness will need to be performed. Measures to improve the outcome of GDM pregnancy will also need to be addressed in the future.     

Atherosclerotic Carotid Plaque Composition and Incident Stroke and Coronary Events

BackgroundIncreasing evidence suggests that atherosclerotic plaque composition rather than plaque size is linked to ischemic cardiovascular events, yet largescale population-based data in asymptomatic individuals remain scarce.ObjectivesThis study sought to investigate carotid plaque composition in relation to incident stroke and coronary heart disease (CHD) in a population-based setting.MethodsBetween 2007 and 2012, 1,349 persons (mean age 72 years, 49.5% women) from the population-based Rotterdam Study who were free from a history of stroke or CHD, in whom carotid ultrasonography showed subclinical atherosclerosis, and who underwent high-resolution magnetic resonance imaging of the carotid arteries to assess plaque characteristics. These included the presence of specific plaque components (intraplaque hemorrhage [IPH], lipid-rich necrotic core, and calcification), and measures of plaque size (maximum plaque thickness and presence of stenosis of more than 30%). Individuals were continuously followed for the occurrence of stroke or CHD until January 1, 2015. The authors used Cox regression models to assess the association of the plaque characteristics with the incidence of stroke and CHD, with adjustments for age, sex, and cardiovascular risk factors.ResultsDuring a median of 5.1 years’ follow-up for stroke and 4.8 years for CHD, 51 individuals had a stroke and 83 developed CHD. Independent of maximum plaque thickness and cardiovascular risk factors, the presence of IPH was associated with incident stroke and CHD (fully adjusted hazard ratio: 2.42 [95% confidence interval: 1.30 to 4.50], and 1.95 [95% confidence interval: 1.20 to 3.14]). Presence of a lipid-rich necrotic core and calcification were not associated with stroke or CHD.ConclusionsThe presence of IPH in the carotid atherosclerotic plaque is an independent risk factor for stroke and CHD. These findings indicate the promise of IPH as a marker of plaque vulnerability in healthy persons with subclinical atherosclerosis.