Commensal bacteria weaken the intestinal barrier by suppressing epithelial neuropilin-1 and Hedgehog signaling

The gut microbiota influences intestinal barrier integrity through mechanisms that are incompletely understood. Here we show that the commensal microbiota weakens the intestinal barrier by suppressing epithelial neuropilin-1 (NRP1) and Hedgehog (Hh) signaling. Microbial colonization of germ-free mice dampens signaling of the intestinal Hh pathway through epithelial Toll-like receptor (TLR)-2, resulting in decreased epithelial NRP1 protein levels. Following activation via TLR2/TLR6, epithelial NRP1, a positive-feedback regulator of Hh signaling, is lysosomally degraded. Conversely, elevated epithelial NRP1 levels in germ-free mice are associated with a strengthened gut barrier. Functionally, intestinal epithelial cell-specific Nrp1 deficiency (Nrp1ΔIEC) results in decreased Hh pathway activity and a weakened gut barrier. In addition, Nrp1ΔIEC mice have a reduced density of capillary networks in their small intestinal villus structures. Collectively, our results reveal a role for the commensal microbiota and epithelial NRP1 signaling in the regulation of intestinal barrier function through postnatal control of Hh signaling.

α-Linolenic Acid-Rich Diet Influences Microbiota Composition and Villus Morphology of the Mouse Small Intestine

α-Linolenic acid (ALA) is well-known for its anti-inflammatory activity. In contrast, the influence of an ALA-rich diet on intestinal microbiota composition and its impact on small intestine morphology are not fully understood. In the current study, we kept adult C57BL/6J mice for 4 weeks on an ALA-rich or control diet. Characterization of the microbial composition of the small intestine revealed that the ALA diet was associated with an enrichment in Prevotella and Parabacteroides. In contrast, taxa belonging to the Firmicutes phylum, including Lactobacillus, Clostridium cluster XIVa, Lachnospiraceae and Streptococcus, had significantly lower abundance compared to control diet. Metagenome prediction indicated an enrichment in functional pathways such as bacterial secretion system in the ALA group, whereas the two-component system and ALA metabolism pathways were downregulated. We also observed increased levels of ALA and its metabolites eicosapentanoic and docosahexanoic acid, but reduced levels of arachidonic acid in the intestinal tissue of ALA-fed mice. Furthermore, intestinal morphology in the ALA group was characterized by elongated villus structures with increased counts of epithelial cells and reduced epithelial proliferation rate. Interestingly, the ALA diet reduced relative goblet and Paneth cell counts. Of note, high-fat Western-type diet feeding resulted in a comparable adaptation of the small intestine. Collectively, our study demonstrates the impact of ALA on the gut microbiome and reveals the nutritional regulation of gut morphology.

Coagulation factor 9-deficient mice are protected against dextran sulfate sodium-induced colitis

Patients with inflammatory bowel disease (IBD) are susceptible to thromboembolism. Interestingly, IBD occurs less frequently in patients with inherited bleeding disorders. Therefore, we analyzed whether F9-deficiency is protective against the onset of acute colitis in a genetic hemophilia B mouse model. In the 3.5% dextran sulfate sodium (DSS)-induced colitis model, F9-deficient mice were protected from body-weight loss and had a reduced disease activity score. We detected decreased colonic myeloperoxidase activity and decreased CXCL1 levels in DSS-treated F9-deficient mice compared with wild-type (WT) littermate controls, indicating decreased neutrophil infiltration. Remarkably, we identified expression of coagulation factor IX (FIX) protein in small intestinal epithelial cells (MODE-K). In epithelial cell cultures, cellular FIX protein expression was increased following stimulation with the bacterial Toll-like receptor agonists lipopolysaccharide, macrophage-activating lipopeptide-2 and Pam3CSK4. Thus, we revealed a protective role of F9-deficiency in DSS-induced colitis and identified the intestinal epithelium as a site of ectopic FIX.

This article has an associated First Person interview with the first author of the paper.

Summary: Since IBD incidence is less frequent in patients with inherited bleeding disorders, we explored and demonstrated that F9-deficiency is protective against DSS-induced acute colitis in a hemophilia B mouse model.

The importance of interictal electroencephalography in paroxysmal states

INTRODUCTION

Electroencephalography (EEG) is a non-invasive investigation method playing an important role in differential diagnostics of seizures. In this article authors point out to its importance, but also limitations.

MATERIAL AND METHODS

Native interictal EEG findings were evaluated in inpatients after solitary unprovoked epileptic seizures (n=84), patients with sporadic epileptic seizures (n=179), patients with "chronic" epilepsy (n=324), outpatients with epilepsy (n=300), patients with syncope (n=100), patients with neurocardiogenic syncope (n=70), patients with migraine (n=100) and patients with tetanic syndrome (n=100). EEG findings were evaluated as normal or abnormal and abnormal findings were further divided into epileptic and non-epileptic, focal and generalized.

RESULTS

In native EEG, epileptic manifestations were registered in 14.29 % of patients after solitary unprovoked epileptic seizures, in 25.7 % of patients with sporadic epileptic seizures, in 37.34 % of patients with chronic epilepsy and in 32 % of outpatients with epilepsy. Interictal EEG abnormalities (epileptiform and non-epileptiform) in non-epileptic diagnoses were at least registered in patients with syncope, but also in this group abnormal findings occurred in 30 % of them. We registered epileptiform abnormalities in 5 % of patients with migraine, in 4 % of patients with tetanic syndrome and in 2 % of patients with syncope.

CONCLUSION

The diagnosis of epilepsy and non-epileptic seizures is a only a clinical diagnosis. EEG is a very important investigational method in this group of patients, but still only additional (Tab. 4, Fig. 2, Ref. 14).

Clinical accuracy of the distinction between Alzheimer's disease and frontotemporal lobar degeneration

Alzheimer's disease (AD) is the most common cause of dementia. Frontotemporal lobar degeneration (FTLD), although less prevalent overall, is almost as common as AD in patients under the age of 65. AD and FTLD are histopathologically distinct, with AD being characterised by extracellular amyloid plaques and intraneuronal neurofibrillary tangles, and FTLD by the presence of non-AD histological pathology, most commonly either tau-positive inclusions or ubiquitin-positive or TDP 43 positive inclusions. Clinically, AD and FTLD may occur with overlapping symptoms, especially in the early stages of the disease. In the case of Alzheimer's disease, it is represented by isolated decline of recent episodic memory; later on, by the impairment of time and space orientation, whereby the alteration of social behaviour and amnesic aphasia occur predominantly in the advanced phases of the disease. Frontotemporal lobar degeneration is demonstrated in three clinical subunits: 1) The behavioural-dysexecutive variant of FTLD (frontotemporal dementia, the frontal variant of FTLD, {fvFTLD}), 2) Progressive non-fluent aphasia, 3) Semantic dementia (SD) with the profound impairment of social conduct (fvFTLD) or with severe speech impairment (PNFA, SD). Considering the different clinical symptomatology with FTLD diagnostics, it is necessary to use different psychometric tests than in the case of Alzheimer's disease. Therapy and the degree of dependence of the affected person are also different. All three diseases within the FTLD category, mainly the behavioural-dysexecutive variant, require a higher level of nursing care on the part of other persons or institutions in comparison with Alzheimer's disease. The goal of our publication is to point to the differences in clinical manifestation and the findings of auxiliary examinations that are helpful in the clinical accuracy of the distinction between these two types of dementia (Tab. 1, Fig. 3, Ref. 18).

[Patellofemoral pain syndrome in young men compared to a normal population exposed to the same physical strain]

AIM

The causes of the patellofemoral pain syndrome, especially in young patients, continue to be largely unknown. The purpose of the study was to determine the extent to which weight and activities that impose a strain on the knee influence the occurrence of patellofemoral pain in young, physically active men.

METHOD

248 soldiers on mandatory military service were included in the study. 133 persons had pain in the knee prior to or during military service while 115 persons had no symptoms in the knee. Anthropometric data and patient history were recorded for all individuals. This was followed by clinical examination.

RESULTS

Age distribution and body mass index were identical in both groups. However, significantly more subjects in the group with pain prior to military service had been active sportsmen while a significantly larger number of normal individuals had had jobs that strained the knees. The greatest difference, however, was seen in the number of previous injuries. These were much more common in the group that had pain and the injuries most commonly were contusions.

CONCLUSION

It is well known that previous injuries and sports favor the emergence of patellar pain. However, persistent strain on the knee at work appears to be less commonly associated with this symptom. The individual's body-mass index was of no importance in this context.