Disturbances in gastrointestinal (GI) microbiota could play a significant role in the development of GI cancers, but the underlying mechanisms remain largely unclear. While some bacteria seem to ...facilitate carcinogenesis, others appear to be protective. So far only one bacterium (
Helicobacter pylori
) has been classified by the International Agency for Cancer Research as carcinogenic in humans but many other are the subject of intense research. Most studies on the role of microbiota in GI tract oncogenesis focus on pancreatic and colorectal cancers with the following three species:
Helicobacter pylori, Escherichia coli
, and
Porphyromonas gingivalis
as likely causative factors. This review summarizes the role of bacteria in GI tract oncogenesis.
The purpose of this review is to summarize current knowledge about the gut microbiota in neuropsychiatric disorders. It is estimated that the human gut is colonized by up to 1018 microorganisms, ...mostly anaerobic bacteria. The gut microbiome is responsible for multiple functions, e.g. tightness of the intestine barrier, digestion and absorption. The correlation between gut dysbiosis and development of psychiatric, autoimmune and allergic diseases as well as bidirectional communication between brain and gut microflora have been shown. Recent findings suggest that specific bacteria can be involved in the development of clinical conditions, such as Autism Spectrum Disorders, depression and schizophrenia, and microbiota may be a target for therapeutic intervention providing novel treatment strategies.
Inflammation of forebrain and hindbrain nuclei controlling the sympathetic nervous system (SNS) outflow from the brain to the periphery represents an emerging concept of the pathogenesis of ...neurogenic hypertension. Angiotensin II (Ang-II) and prorenin were shown to increase production of reactive oxygen species and pro-inflammatory cytokines (interleukin-1 beta (IL-1β), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α)) while simultaneously decreasing production of interleukin-10 (IL-10) in the paraventricular nucleus of the hypothalamus and the rostral ventral lateral medulla. Peripheral chronic inflammation and Ang-II activity seem to share a common central mechanism contributing to an increase in sympathetic neurogenic vasomotor tone and entailing neurogenic hypertension. Both hypertension and obesity facilitate the penetration of peripheral immune cells in the brain parenchyma. We suggest that renin-angiotensin-driven hypertension encompasses feedback and feedforward mechanisms in the development of neurogenic hypertension while low-intensity, chronic peripheral inflammation of any origin may serve as a model of a feedforward mechanism in this condition.
The immune system response and inflammation play a key role in brain injury during and after a stroke. The acute immune response is responsible for secondary brain tissue damage immediately after the ...stroke, followed by immunosuppression due to sympathetic nervous system activation. The latter increases risk of infection complications, such as pneumonia. The pneumonia-related inflammatory state can release a bystander autoimmune response against central nervous system antigens, thereby initiating a vicious circle. The aim of this review is to summarize the relationship between ischemic stroke, sympathetic nervous system activation and pulmonary infection.
•Increased plasma trimethylamine N-oxide (a bacteria metabolite) is a cardiovascular risk marker.•High salt intake was found to increase plasma trimethylamine N-oxide in rats.•High salt intake ...altered gut bacteria composition.•High-salt diet may affect interplay between gut bacteria and host homeostasis.
A high-salt diet is considered a cardiovascular risk factor; however, the mechanisms are not clear. Research suggests that gut bacteria-derived metabolites such as trimethylamine N-oxide (TMAO) are markers of cardiovascular diseases. We evaluated the effect of high salt intake on gut bacteria and their metabolites plasma level.
Sprague Dawley rats ages 12–14 wk were maintained on either water (controls) or 0.9% or 2% sodium chloride (NaCl) water solution (isotonic and hypertonic groups, respectively) for 2 wk. Blood plasma, urine, and stool samples were analyzed for concentrations of trimethylamine (TMA; a TMAO precursor), TMAO, and indoxyl sulfate (indole metabolite). The gut-blood barrier permeability to TMA and TMA liver clearance were assessed at baseline and after TMA intracolonic challenge test. Gut bacterial flora was analyzed with a 16S ribosomal ribonucleic acid (rRNA) gene sequence analysis.
The isotonic and hypertonic groups showed a significantly higher plasma TMAO and significantly lower 24-hr TMAO urine excretion than the controls. However, the TMA stool level was similar between the groups. There was no significant difference between the groups in gut-blood barrier permeability and TMA liver clearance. Plasma indoxyl concentration and 24-hr urine indoxyl excretion were similar between the groups. There was a significant difference between the groups in gut bacteria composition.
High salt intake increases plasma TMAO concentration, which is associated with decreased TMAO urine excretion. Furthermore, high salt intake alters gut bacteria composition. These findings suggest that salt intake affects an interplay between gut bacteria and their host homeostasis.
Chronic hepatitis C virus (HCV) infection is commonly associated with depression and cognitive dysfunction, the cause of which could be related to the HCV neuroinvasion and/or state of chronic ...inflammation. Viral sequences and proteins were previously detected in the brain and since blood leukocytes can cross the blood–brain barrier, they could provide viral access to the CNS. Eighty chronic hepatitis C patients were tested for viral replication in PBMCs (detection of the HCV RNA-negative strand) and serum cytokines. Depression was assessed by the Beck Depression Inventory (BDI), neuroticism by the Eysenck Personality Inventory (N/EPO-R), and anxiety by the State-Trait Anxiety Inventory (STAI) while neurocognitive testing included the Wisconsin Card Sorting Test (WCST), Ruff Figural Fluency Test (RFFT), California Verbal Learning Test (CVLT), and Grooved Pegboard Test (GPT). The HCV RNA-negative strand was detected in PBMCs from 24 (30%) patients and these patients had significantly higher BDI scores (median 12.5 IQR 6.3–20.5 vs. median 8.00 IQR 3–12; p = 0.013). Both depression and anxiety correlated positively with IL-8 while cognitive flexibility, executive function, problem-solving skills, memory, and motor functioning correlated negatively with some proinflammatory cytokines. Our findings suggest that due to chronic HCV infection, the brain function is negatively affected by both viral replication in PBMCs and by the immune activation state.
Identification of pathogens causing viral encephalitis remains challenging, and in over 50% of cases the etiologic factor remains undetermined. Next-generation sequencing (NGS) based metagenomics has ...been successfully used to detect novel and rare infections, but its value for routine diagnosis of encephalitis remains unclear. The aim of the present study was to determine the sensitivity of shotgun metagenomic sequencing protocols, which include preamplification, and testing it against cerebrospinal fluid (CSF) samples from encephalitis patients. For sensitivity testing HIV and HBV positive sera were serially diluted in CSF from an uninfected patient. NGS repeatedly detected HIV and HBV sequences present at concentrations from 10
to 10
and from 10
to 10 viral copies/reaction, respectively. However, when the same protocols were applied to RT-PCR/PCR positive CSF samples from 6 patients with enteroviral encephalitis (median viral load 47 copies/ml) and 15 patients with HSV, CMV or VZV encephalitis (median viral load 148 copies/ml), only 7 (28.6%) were identified as positive. In conclusions, while NGS has the advantage of being able to identify a wide range of potential pathogens it seems to be less sensitive compared to the standard amplification-based assays in the diagnosis of encephalitis, where low viral loads are common.
Abstract
Most Hepatitis C virus (HCV)-infected subjects develop chronic infection, whereas a minority clear the virus in the early phase of infection. We analyzed factors associated with outcome ...(chronicity vs clearance) during the preclinical seronegative phase of community-acquired HCV infection. Among 17.5 million blood donations in the years 2000–2016, 124 blood donors were found to be HCV RNA-positive/anti-HCV-negative. All were contacted after 0.5–12.7 years and 40 responded and provided blood sample. Hypervariable region 1 was analyzed by ultradeep pyrosequencing and cytokines in serum were quantified by Luminex (R&D Systems) multiplex immunoassay. Twenty-one (52.5%) donors were found to be HCV-RNA-positive, while 19 (47.5%) were HCV RNA negative (none received antiviral treatment). All but one seroconverted to anti-HCV. Donors with resolving hepatitis did not differ significantly from donors with chronic infection with respect to age, genotypes, IL28B polymorphisms, number of viral variants, nucleotide diversity per site or the overall number of nucleotide substitutions. However, the former group had significantly higher levels of IL-1beta, IL-1RA, IL-6, IFN-gamma and FGF-2 in serum. In our study of community-acquired acute hepatitis C approximately half of all subjects eliminated the virus spontaneously, and this clearance was associated with marked cytokine response in the early seronegative stage of infection.
Dermacentor reticulatus plays an important role in the maintenance of pathogens of medical and veterinary importance in the environment. Currently two isolated populations of D. reticulatus are ...present in Poland--Western and Eastern. The range of the Eastern population covers endemic areas in eastern Poland but this population is expanding westwards creating an expansion zone in the centre of the country. The expansion zone in western Poland is occupied by the recently discovered Western population, spreading eastwards.
Questing adult ticks (n = 2585) were collected in 2012-2014 in endemic regions of north-eastern (Warmińsko-Mazurskie Voivodeship) and central Poland (Masovian Voivodeship) and in the expansion zones in central and western Poland, in the region between the Vistula River and the western border of the country. Amplification of Babesia, Rickettsia spp. and Borrelia burgdorferi sensu lato DNAs was performed using specific starters. RNA of the TBE virus was detected using RT-PCR and representative PCR products were sequenced and compared with sequences deposited in GenBank.
Of the total 2585 examined ticks, 1197 (46.3 %) were infected with at least one pathogen. Overall prevalence of pathogens was 4.18 % (108/2585) for Babesia spp., 44.10 % (1140/2585) for Rickettsia spp., 0.09 % (1/1107) for Borrelia afzelii and 7.6 % (7/92) for TBEV. Sequence analysis of DNA showed 99.86 % similarity to R. raoulti and 99.81 % to B. canis. One male from north-eastern Poland was infected with B. microti. Prevalence of R. raoulti was highest in the Western population (52.03 %) and lowest in the Eastern population in north-eastern Poland (34.18 %). Babesia canis was not detected in 592 ticks collected in the Western population, while in the Eastern population overall prevalence was 5.42 %. There were significant differences in the prevalence of B. canis between tick samples from northern (0.68 %), central (1.18 %) and southern (14.8 %) areas of the expansion zone in central Poland.
Our study found significant differences between the range and prevalence of vectored pathogens in D. reticulatus from the endemic areas and newly inhabited expansion zones. The differences were likely associated with the different time of settlement or 'source' of ticks populations, the Eastern and the Western one.
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