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result(s) for
"Sechi, Leonardo A."
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Mycobacterium avium ss. paratuberculosis Zoonosis – The Hundred Year War – Beyond Crohn’s Disease
2015
The factitive role of Mycobacterium avium ss. paratuberculosis (MAP) in Crohn's disease has been debated for more than a century. The controversy is due to the fact that Crohn's disease is so similar to a disease of MAP-infected ruminant animals, Johne's disease; and, though MAP can be readily detected in the infected ruminants, it is much more difficult to detect in humans. Molecular techniques that can detect MAP in pathologic Crohn's specimens as well as dedicated specialty labs successful in culturing MAP from Crohn's patients have provided strong argument for MAP's role in Crohn's disease. Perhaps more incriminating for MAP as a zoonotic agent is the increasing number of diseases with which MAP has been related: Blau syndrome, type 1 diabetes, Hashimoto thyroiditis, and multiple sclerosis. In this article, we debate about genetic susceptibility to mycobacterial infection and human exposure to MAP; moreover, it suggests that molecular mimicry between protein epitopes of MAP and human proteins is a likely bridge between infection and these autoimmune disorders.
Journal Article
Enterotoxigenic Bacteroides fragilis: A Possible Etiological Candidate for Bacterially-Induced Colorectal Precancerous and Cancerous Lesions
2020
Enterotoxigenic
(ETBF) produces
toxin (BFT), which is associated with acute diarrheal, inflammatory bowel disease, and colorectal cancer (CRC). In experimental models, ETBF has been shown to contribute to colon carcinogenesis. The present study was conducted to investigate mucosal colonization of ETBF in the colon to find a possible association between the presence of ETBF and precancerous and cancerous lesions. The mucosal biopsies of involved sites were obtained from 68 patients with precancerous and cancerous lesions and 52 healthy controls (HC). The samples were cultured on Bacteroides Bile Esculin agar. Then, specific primers were designed to detect
and
gene using quantitative real-time PCR, and the possible links of ETBF with clinicopathological characteristics was evaluated. Also real-time PCR was performed to detect the
gene subtypes.
was detected in 51% of the patients and 48% of HCs cultures. The 16SrRNA gene was found to be present in 63 and 81% of the patients and HCs' samples, respectively. Moreover, the
gene was detected in 47 and 3.8% of the patients and HCs, respectively. Also,
was significantly more abundant in the patients' samples compared to those of HCs. In the patient group, higher odds ratio (OR) of ETBF was significantly associated with serrated lesions and adenoma with low-grade dysplasia. The
gene was the most prevalent subtype of
, followed by the
gene. This was the first study in Iran to demonstrate increased positivity of ETBF in patients with precancerous and cancerous lesions. In this study, the
gene was found to be associated with CRC, especially in the patients with precancerous lesions and initial carcinogenic lesions. Moreover, the results suggest that mucosal BFT exposure is common and could be a risk factor and a screening marker for developing CRC.
Journal Article
Alcohol Intake and Arterial Hypertension: Retelling of a Multifaceted Story
by
Sechi, Leonardo A.
,
Bulfone, Luca
,
Soardo, Giorgio
in
alcohol drinking
,
Alcohol Drinking - adverse effects
,
Alcohol use
2023
Alcoholic beverages are common components of diets worldwide and understanding their effects on humans’ health is crucial. Because hypertension is the leading risk factor for cardiovascular diseases and all-cause mortality, the relationship of alcohol consumption with blood pressure (BP) has been the subject of extensive investigation. For the purpose of this review, we searched the terms “alcohol”, “ethanol”, and “arterial hypertension” on Pubmed MeSH and selected the most relevant studies. Short-term studies showed a biphasic BP response after ingestion of high doses of alcohol, and sustained alcohol consumption above 30 g/day, significantly, and dose-dependently, increased the risk for hypertension. These untoward effects of alcoholic beverages on BP can be mediated by a multiplicity of neurohormonal mechanisms. In addition to the effects on BP, excess alcohol intake might contribute to cardiac and renal hypertensive organ damage, although some studies suggest possible benefits of moderate alcohol consumption on additional cardiovascular risk factors, such as diabetes and lipoprotein(a). Some intervention studies and cumulative analyses support the evidence of a benefit of the reduction/withdrawal of alcohol consumption on BP and cardiovascular outcomes. This is why guidelines of scientific societies recommend avoidance or limitation of alcohol intake below one unit/day for women and two units/day for men. This narrative article overviews all these topics, providing an update of the current knowledge on the relationship between alcohol and BP.
Journal Article
Efficacy of BCG vaccine in animal models of neurological disorders
by
Ruberto, Stefano
,
Sechi, Leonardo A
,
Cossu, Davide
in
Allergy and Immunology
,
Alzheimer's disease
,
Animal models
2022
The Bacillus Calmette-Guerin (BCG) vaccine can modulate the immune response via antigen-specific immune response, but also it can confer nonspecific protection and therapeutic benefits in several neurological conditions through different heterologous effects of vaccination. However, the precise mechanism of action of BCG remains unclear. In this review, different mechanisms underlying BCG-mediated immunity will be explained in animal models that reflects characteristic feature of neuroinflammatory and neurodegenerative disorders such as multiple sclerosis, Alzheimer’s and Parkinson’s diseases. Furthermore, evidence for a beneficial effect of the BCG on neuropsychiatric disorders, will be also discussed.
Journal Article
Natalizumab Therapy Modulates miR-155, miR-26a and Proinflammatory Cytokine Expression in MS Patients
by
Caggiu, Elisa
,
Leoni, Stefania
,
Sechi, Leonardo A.
in
Adult
,
Biology and Life Sciences
,
Biomarkers
2016
MicroRNAs fine-tune the regulation of Th1/Th17 lymphocyte subsets in multiple sclerosis. We investigated the expression of miRNAs (previously associated with mycobacterial and viral infections) in MS patients and healthy donors (HD) following 6 months natalizumab therapy. In addition, Th1/Th17 cytokines and the presence of anti-EBNA1/VCA IgG in MS patients with different pattern of miRNA expression have been evaluated. MiR-155, miR-26a, miR-132, miR-146a and Th1/Th17 cytokines expression was detected by RT-real time PCR; moreover anti-EBNA1 and VCA IgG titres were measured by ELISA. We observed an up-regulation of miR-155 (p value = 0.009) and miR-132 (p value = 0.04) in MS patients compared to HD. In MS patients, IL-17a (p = 0.037), IFN γ (p = 0.012) and TNFα (p = 0.015) but not IL-6 were over-expressed compared to HD. Two different miRNAs patterns associated to the expression of different cytokines were observed in the MS cohort. Moreover, a down-regulation of miR-155 and miR-26a was seen in MS patients during and after natalizumab therapy. MS patients that over-expressed miR-155 showed a higher EBNA1 IgG titer than MS patients with high levels of miR-26a. In conclusions the expression of particular miRNAs modulates the pro-inflammatory cytokine expression and the humoral response against EBV and this expression is natalizumab regulated.
Journal Article
Transcriptional Upregulation of HERV-env Genes Under Simulated Microgravity
by
Sechi, Leonardo A.
,
Pantaleo, Antonella
,
Jasemi, Seyedesomaye
in
Caco-2 Cells
,
Cancer
,
Cell Line
2025
Human endogenous retroviruses (HERVs) constitute about 8% of the human genome. The overexpression of HERVs has been detected in various inflammatory disorders like neuro-inflammation disorders and cancer. Interestingly, it has been reported that stress conditions facilitate HERV expression. Space travel exposes astronauts to microgravity environments (a stress condition), which may result in the activation of HERVs and might influence pathogenic outcomes during and after space flight. This study aimed to elucidate the transcriptional activity of three HERV families (W, K, and H) and cytokine genes (IL-1, IL-6, and TNF-α) in different cell lines under microgravity (μg) conditions and compare them with the results obtained under normal gravity (ng; 1g). We evaluated the expression of HERVs (HERV-K env, HERV-K gag, HERV-W env, and HERV-H env) and cytokine gene expression (IL-1, IL-6, and TNF-α) in neuroblastoma (SH-SY5Y), HEp-2, and Caco-2 cell lines under simulated μg and 1g conditions. In SH-SY5Y cells, the expression level of the IL-1, IL-6, HERV-H env, HERV-K env, HERV-K gag, and HERV-W env genes was significantly increased when exposed to short-term μg (3 and 6 h). The expression of TNF-α remained unchanged throughout all time points. Additionally, in Caco-2 cells, the expression of the HERV-K env, HERV-K gag, and IL-1 genes was significantly higher after 6 h of incubation in μg conditions compared to 1g. There was no statistically significant difference in the expression levels of the HERV-W env, HERV-H env, IL6, and TNF-α genes between the μg and 1g conditions. Moreover, in HEp-2 cells, the expression of the IL-1, IL6, TNF-α, HERV-H env, HERV-K env, HERV-K gag, and HERV-W env genes significantly increased following short-term incubation in μg (3 h, 6 h) and then decreased to levels comparable to those observed in the 1g condition. Taken together, the dysregulation of cytokine and HERV gene expression was observed under the simulated μg condition. The patterns of these dysregulations varied throughout cell lines, which demands further investigation for human health protection in space.
Journal Article
Diagnostic, Prognostic, and Therapeutic Roles of Gut Microbiota in COVID-19: A Comprehensive Systematic Review
by
Arbabi, Mahta
,
Sechi, Leonardo A.
,
Tahvildari, Azin
in
Bacteroides
,
Bifidobacterium
,
Cellular and Infection Microbiology
2022
The Coronavirus Disease 2019 (COVID-19) pandemic caused by Severe Acute Respiratory Coronavirus 2 (SARS-CoV-2) emerged in late December 2019. Considering the important role of gut microbiota in maturation, regulation, and induction of the immune system and subsequent inflammatory processes, it seems that evaluating the composition of gut microbiota in COVID-19 patients compared with healthy individuals may have potential value as a diagnostic and/or prognostic biomarker for the disease. Also, therapeutic interventions affecting gut microbial flora may open new horizons in the treatment of COVID-19 patients and accelerating their recovery.
A systematic search was conducted for relevant studies published from December 2019 to December 2021 using Pubmed/Medline, Embase, and Scopus. Articles containing the following keywords in titles or abstracts were selected: \"SARS-CoV-2\" or \"COVID-19\" or \"Coronavirus Disease 19\" and \"gastrointestinal microbes\" or \"dysbiosis\" or \"gut microbiota\" or \"gut bacteria\" or \"gut microbes\" or \"gastrointestinal microbiota\".
Out of 1,668 studies, 22 articles fulfilled the inclusion criteria and a total of 1,255 confirmed COVID-19 patients were examined. All included studies showed a significant association between COVID-19 and gut microbiota dysbiosis. The most alteration in bacterial composition of COVID-19 patients was depletion in genera
,
,
,
,
,
,
, and
and enrichment of
,
,
,
,
,
, and
Also, some gut microbiome alterations were associated with COVID-19 severity and poor prognosis including the increment of
,
,
,
,
,
,
,
,
,
, and
spp. and the decrement of
,
,
,
, and the Firmicutes/Bacteroidetes ratio.
Our study showed a significant change of gut microbiome composition in COVID-19 patients compared with healthy individuals. This great extent of impact has proposed the gut microbiota as a potential diagnostic, prognostic, and therapeutic strategy for COVID-19. There is much evidence about this issue, and it is expected to be increased in near future.
Journal Article
Mycobacterium avium subspecies paratuberculosis (MAP) infection, and its impact on gut microbiome of individuals with multiple sclerosis
2024
The microbial ecology of
Mycobacterium avium subspecies paratuberculosis
infections (MAP) within the context of Multiple Sclerosis (MS) is largely an unexplored topic in the literature. Thus, we have characterized the compositional and predicted functional differences of the gut microbiome between MS patients with MAP (MAP+) and without (MAP−) infection. This was done in the context of exposome differences (through self-reported filled questionnaires), principally in anthropometric and sociodemographic patterns to gain an understanding of the gut microbiome dynamics. 16S rRNA microbiome profiling of faecal samples (n = 69) was performed for four groups, which differed by disease and MAP infection: healthy cohort (HC) MAP−; HC MAP+ ; MS MAP−; and MS MAP+ . Using a dynamic strategy, with MAP infection and time of sampling as occupancy models, we have recovered the core microbiome for both HC and MS individuals. Additional application of neutral modeling suggests key genera that are under selection pressure by the hosts. These include members of the phyla
Actinobacteriota, Bacteroidota
, and
Firmicutes
. As several subjects provided multiple samples, a
Quasi Conditional Association Test
that incorporates paired-nature of samples found major differences in
Archaea
. To consolidate treatment groups, confounders, microbiome, and the disease outcome parameters, a mediation analysis is performed for MS cohort. This highlighted certain genera i.e.,
Sutterella
,
Akkermansia
,
Bacteriodes
,
Gastranaerophilales
,
Alistipes
,
Balutia
,
Faecalibacterium
,
Lachnospiraceae
,
Anaerostipes
,
Ruminococcaceae
,
Eggerthellaceae
and
Clostridia-UCG-014
having mediatory effect using disease duration as an outcome and MAP infection as a treatment group. Our analyses indicate that the gut microbiome may be an important target for dietary and lifestyle intervention in MS patients with and without MAP infection.
Journal Article
A Review on Mycobacteriophages: From Classification to Applications
2022
Mycobacterial infections are a group of life-threatening conditions triggered by fast- or slow-growing mycobacteria. Some mycobacteria, such as Mycobacterium tuberculosis, promote the deaths of millions of lives throughout the world annually. The control of mycobacterial infections is influenced by the challenges faced in the diagnosis of these bacteria and the capability of these pathogens to develop resistance against common antibiotics. Detection of mycobacterial infections is always demanding due to the intracellular nature of these pathogens that, along with the lipid-enriched structure of the cell wall, complicates the access to the internal contents of mycobacterial cells. Moreover, recent studies depicted that more than 20% of M. tuberculosis (Mtb) infections are multi-drug resistant (MDR), and only 50% of positive MDR-Mtb cases are responsive to standard treatments. Similarly, the susceptibility of nontuberculosis mycobacteria (NTM) to first-line tuberculosis antibiotics has also declined in recent years. Exploiting mycobacteriophages as viruses that infect mycobacteria has significantly accelerated the diagnosis and treatment of mycobacterial infections. This is because mycobacteriophages, regardless of their cycle type (temperate/lytic), can tackle barriers in the mycobacterial cell wall and make the infected bacteria replicate phage DNA along with their DNA. Although the infectivity of the majority of discovered mycobacteriophages has been evaluated in non-pathogenic M. smegmatis, more research is still ongoing to find mycobacteriophages specific to pathogenic mycobacteria, such as phage DS6A, which has been shown to be able to infect members of the M. tuberculosis complex. Accordingly, this review aimed to introduce some potential mycobacteriophages in the research, specifically those that are infective to the three troublesome mycobacteria, M. tuberculosis, M. avium subsp. paratuberculosis (MAP), and M. abscessus, highlighting their theranostic applications in medicine.
Journal Article
Antibiotic resistance pattern of Bacteroides fragilis isolated from clinical and colorectal specimens
by
Ahmadinejad, Zahra
,
Fazeli, Mohammad Sadegh
,
Sechi, Leonardo A.
in
Anaerobic bacteria
,
Antibacterial agents
,
Antibiotic resistance
2021
Background
Bacteroides fragilis
is a part of the normal gastrointestinal flora, but it is also the most common anaerobic bacteria causing the infection. It is highly resistant to antibiotics and contains abundant antibiotic resistance mechanisms.
Methods
The antibiotic resistance pattern of 78 isolates of
B. fragilis
(22 strains from clinical samples and 56 strains from the colorectal tissue) was investigated using agar dilution method. The gene encoding
Bacteroides fargilis
toxin
bft
, and antibiotic resistance genes were targeted by PCR assay.
Results
The highest rate of resistance was observed for penicillin G (100%) followed by tetracycline (74.4%), clindamycin (41%) and cefoxitin (38.5%). Only a single isolate showed resistance to imipenem which contained
cfiA
and
IS1186
genes. All isolates were susceptible to metronidazole. Accordingly,
tetQ
(87.2%),
cepA
(73.1%) and
ermF
(64.1%) were the most abundant antibiotic-resistant genes identified in this study. MIC values for penicillin, cefoxitin and clindamycin were significantly different among isolates with the
cepA
,
cfxA
and
ermF
in compare with those lacking such genes. In addition, 22.7 and 17.8% of clinical and GIT isolates had the
bft
gene, respectively.
Conclusions
The finding of this study shows that metronidazole is highly in vitro active agent against all of
B. fragilis
isolates and remain the first-line antimicrobial for empirical therapy.
Journal Article