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Bitar, Aziz
Publications (10 of 10) Show all publications
Schéle, I., Holmström, S., Boman, J. & Bitar, A. (2025). Att vara en duktig student – en möjlig börda?: akademisk kultur, psykologisk trygghet och hållbarhet i högre utbildning. In: : . Paper presented at The Art of Teaching - Universitetspedagogisk konferens, Umeå universitet, Sverige, 6-7 november, 2025.
Open this publication in new window or tab >>Att vara en duktig student – en möjlig börda?: akademisk kultur, psykologisk trygghet och hållbarhet i högre utbildning
2025 (Swedish)Conference paper, Oral presentation only (Refereed)
Abstract [sv]

I högre utbildning lär sig studenter inte enbart ämnesinnehåll – de socialiseras också in i en akademisk kultur där prestation, perfektion och erkännande spelar centrala roller. Denna kultur formar studenters självbild, känsla av tillhörighet och upplevelse av vad som krävs för att lyckas. I detta bidrag lyfter vi hur akademisk prestationskultur påverkar studenters välbefinnande, särskilt de som uppfattas som högpresterande.

Vi diskuterar hur undervisningspraktiker och återkoppling från lärare bidrar till att forma studenters måttstock för prestation, ofta utan att ge dem utrymme för utveckling av egna kriterier. Detta kan leda till ökad prokrastinering, impostorkänslor (känslan av att vara en bluff som riskerar att avslöjas) och en upplevelse av otillräcklighet. Samtidigt tenderar högre utbildning att uppmärksamma underprestation, medan överprestation ofta belönas utan reflektion kring dess konsekvenser.

Vi ställer frågor om vilken kultur vi i akademin bygger kring studier och framtida yrkesliv:

  • Hur påverkar akademins normer studenters upplevelse av inkludering och självständighet?
  • Vilka ideal reproduceras i undervisningen – och vilka risker medför dessa för studenters långsiktiga hälsa och ett hållbart arbetsliv?

I en enkätundersökning bland läkarstudenter vid Umeå universitet framkommer att mer än varannan student skattar en förhöjd eller mycket förhöjd risk för utmattning. Kvinnorna i studien skattade en signifikant högre risk för utmattning och samtidigt signifikant lägre psykologisk trygghet, sannolikt ett uttryck för kultur, normer och klimat i utbildningen. Psykologisk trygghet var negativt korrelerat med impostorkänslor (r=0.33, p<0.001). Resultaten understryker vikten av att vidareutveckla sätt att undervisa som bidrar till en psykologiskt trygg utbildningsmiljö genom tydligt kommunicerade förväntningar, uppmuntra studenter att ställa frågor och skapa fokus på lärande och konstruktiv feedback snarare än prestation och bedömning. Att stödja lärare att utveckla dessa undervisningsfärdigheter kan spela en avgörande roll för att förändra ohälsosamma normer och föråldrade ideal. Riktade interventioner kan öka studenternas känsla av psykologisk trygghet och minska förekomsten av impostorkänslor, stress och utmattning. 

Vi argumenterar alltså för att lärare aktivt bör motverka en kultur av perfektionism, och att det är särskilt viktigt inom professionsutbildningar som leder till ett arbetsliv med höga krav och stort ansvar. Vi avslutar med att konkret diskutera hur vi kan förbereda studenter för ett hållbart arbetsliv genom:

  • undervisning i egenvårdsfärdigheter
  • föregå med gott exempel genom att skapa socialt trygg arbetsmiljö för våra studenter
  • interventioner på individ-, grupp- och organisationsnivå som inte pekar ut individen som svag

Slutsats:För att främja hållbart lärande och välbefinnande behöver vi uppmärksamma även den som presterar – och reflektera över vilken kultur vi tillsammans skapar i högre utbildning.

Keywords
impostorfenomenet, burnout, högre utbildning, studenters välbefinnande, högpresterande studenter
National Category
Applied Psychology Other Medical Sciences not elsewhere specified
Research subject
Psychology; professional development
Identifiers
urn:nbn:se:umu:diva-246246 (URN)
Conference
The Art of Teaching - Universitetspedagogisk konferens, Umeå universitet, Sverige, 6-7 november, 2025
Available from: 2025-11-07 Created: 2025-11-07 Last updated: 2025-11-07Bibliographically approved
Bitar, A., Boman, J. & Kristoffersson, E. (2025). Burnout and psychological safety: a questionnaire study of medical students. Journal of Medical Education and Curricular Development, 12, 1-8
Open this publication in new window or tab >>Burnout and psychological safety: a questionnaire study of medical students
2025 (English)In: Journal of Medical Education and Curricular Development, ISSN 2382-1205, Vol. 12, p. 1-8Article in journal (Refereed) Published
Abstract [en]

Background: Psychological safety—defined as the perception that a group environment is safe for interpersonal risk-taking—could influence the development of burnout among medical students. This study, therefore, sought to investigate the prevalence of burnout, the level of psychological safety, and their association in this population.

Methods: We surveyed undergraduate medical students (n = 944) enrolled in semesters 2 to 10 at a Swedish medical school using a questionnaire containing the Burnout Assessment Tool (BAT-12), Amy Edmondson's Team Psychological Safety Survey, and socio-demographic questions. Data were analyzed using descriptive statistics, t-tests, one-way ANOVA, Pearson's correlation, and hierarchical regression analysis.

Results: A total of 457 medical students (62.6% women) completed the questionnaire (response rate: 48%). Of the participants, 51.4% scored above the cut-off for burnout risk, and among these, 25.6% were at very high risk. Women scored significantly higher on burnout and lower on psychological safety than men. A significant negative association was found between psychological safety and burnout, with psychological safety accounting for an additional 14.3% of the variance in burnout scores.

Conclusions: Our findings suggest that more than half of the surveyed medical students are at risk for burnout and that lower levels of psychological safety are associated with higher levels of burnout. Furthermore, women appear to be at higher risk for burnout and perceive medical school as less psychologically safe than male students. While longitudinal studies are needed to assess the causality between low psychological safety and burnout, our results provide impetus for developing interventions to prevent burnout and addressing an eventual lack of psychological safety in medical school.

Keywords
burnout, psychological safety, burnout assessment tool, questionnaire, Amy Edmondson’s team psychological safety survey, undergraduate medical students
National Category
Other Medical Sciences Pedagogy
Identifiers
urn:nbn:se:umu:diva-242314 (URN)10.1177/23821205251359380 (DOI)
Available from: 2025-07-21 Created: 2025-07-21 Last updated: 2025-07-21Bibliographically approved
Jansson, A., Boman, J., Schéle, I., Holmström, S., Rozental, A., Semb, O., . . . Lindquist, D. (2025). Impostor phenomenon and its association with perceived stress and anxiety among students in medical and social sciences at a Swedish university. Frontiers in Medicine, 12, Article ID 1623792.
Open this publication in new window or tab >>Impostor phenomenon and its association with perceived stress and anxiety among students in medical and social sciences at a Swedish university
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2025 (English)In: Frontiers in Medicine, E-ISSN 2296-858X, Vol. 12, article id 1623792Article in journal (Refereed) Published
Abstract [en]

Introduction: Psychological distress is of concern among university students worldwide, more so than in a comparable working population. The impostor phenomenon (IP) describes feelings of inadequacy often experienced by individuals struggling to internalize success despite evidence to the contrary. IP is prevalent among university students and has been identified as a significant factor in understanding psychological distress within this population. This study aimed to investigate the prevalence of IP and its association with perceived stress and anxiety in dental, law, medical, nursing and psychology university students.

Methods: A web-survey consisting of the Clance Impostor Phenomenon Scale (CIPS), the Perceived Stress Scale-4 (PSS-4), the Generalized Anxiety Disorder-2 (GAD-2), and sociodemographic questions were completed by 968 university students registered at a Swedish university during 2022 and 2023. The prevalence of IP, perceived stress, and anxiety was calculated. Pearson’s correlation coefficient and multiple linear regression were used to examine the relationship between the variables.

Results: 64.0% of the participants scored above the cut off value for experiencing IP (CIPS score ≥62). According to cut-off levels developed to categorize the intensity of IP experiences 8.4% of participants had low experiences of IP, 26.0% moderate, 42.6% frequent, and 23.0% intense experiences of IP. Of all participants, 91.6% had at least moderate experiences of IP and 65.6% had frequent to intense experiences of IP. Women scored significantly higher on CIPS than men. In contrast, neither attending semester nor age group significantly impacted CIPS scores. Finally, there was a moderate correlation between the levels of perceived stress and anxiety, respectively, and the IP scores.

Conclusion: This study suggests that the majority of dental, medical, nursing, psychology and law students experience severe IP. Moreover, this study provides valuable insights into the association of IP with perceived stress and anxiety. The results underscore the significance of exploring IP and its link to psychological distress, suggesting that interventions aimed at diminishing IP may play a crucial role in enhancing the well-being of university students.

Place, publisher, year, edition, pages
Frontiers Media S.A., 2025
Keywords
dental, imposter syndrome, impostor phenomenon, law, medical, nursing, psychology, university students
National Category
Applied Psychology
Identifiers
urn:nbn:se:umu:diva-246819 (URN)10.3389/fmed.2025.1623792 (DOI)001616956600001 ()41234908 (PubMedID)2-s2.0-105021511741 (Scopus ID)
Available from: 2025-11-24 Created: 2025-11-24 Last updated: 2026-03-17Bibliographically approved
Kristoffersson, E., Boman, J. & Bitar, A. (2024). Impostor phenomenon and its association with resilience in medical education: a questionnaire study among Swedish medical students. BMC Medical Education, 24(1), Article ID 782.
Open this publication in new window or tab >>Impostor phenomenon and its association with resilience in medical education: a questionnaire study among Swedish medical students
2024 (English)In: BMC Medical Education, E-ISSN 1472-6920, Vol. 24, no 1, article id 782Article in journal (Refereed) Published
Abstract [en]

Background: Concern over medical students' well-being is a global issue, with studies showing high psychological distress rates. Impostor Phenomenon (IP), i.e., underestimating one's abilities, attributing success to external factors, and feeling like a fraud, has been implicated as one reason behind these troubling findings. Meanwhile, resilience has been suggested to protect against psychological distress. This study aimed to investigate the prevalence of IP and its association with resilience among undergraduate medical students.

Methods: The Clance Impostor Phenomenon Scale (CIPS), the Brief Resilience Scale (BRS), and sociodemographic questions were completed by 457 medical students registered in their 2-10th semester at a Swedish university. Of the respondents, 62.6% identified as women, 36.1% as men, and 1.3% as others.

Results: The prevalence of IP was 58.4% (defined as CIPS score ≥ 62). According to the CIPS scoring guidelines, 10.3% of participants had low IP, 29.5% moderate, 41.6% frequent, and 18.6% intense IP. Of all participants, almost 90% experienced at least moderate and 60.2% frequent to intense IP. Women had significantly higher CIPS scores and lower BRS scores than men. In contrast, neither attending semester nor age group significantly impacted CIPS scores. Finally, there was a moderate inverse correlation between the level of resilience and the prevalence of IP.

Conclusions: Our findings suggest that the majority of Swedish medical students feels like an impostor, and of these students, most do so frequently. Furthermore, IP is more prevalent among female students - who also show lower levels of resilience. Moreover, our results indicated that IP could hinder achieving higher resilience. Future longitudinal studies should investigate how gender norms may contribute to IP feelings and explore the potential advantages of counteracting IP and strengthening resilience among medical students. However, targeted interventions addressing individual students' IP and resilience are insufficient. There is also a need to address structural aspects of the educational environment, such as gender stereotypes, that may contribute to IP.

Place, publisher, year, edition, pages
BioMed Central (BMC), 2024
Keywords
Brief resilience scale, Clance Impostor Phenomenon Scale, resilience, Impostor phenomenon, Questionnaire, Undergraduate medical students
National Category
Health Sciences
Identifiers
urn:nbn:se:umu:diva-228028 (URN)10.1186/s12909-024-05788-2 (DOI)001272965300011 ()39030556 (PubMedID)2-s2.0-85199095252 (Scopus ID)
Available from: 2024-07-24 Created: 2024-07-24 Last updated: 2024-08-21Bibliographically approved
Bitar, A., Amnelius, L., Kristoffersson, E. & Boman, J. (2023). Emotional intelligence among medical students in Sweden: a questionnaire study. BMC Medical Education, 23(1), Article ID 603.
Open this publication in new window or tab >>Emotional intelligence among medical students in Sweden: a questionnaire study
2023 (English)In: BMC Medical Education, E-ISSN 1472-6920, Vol. 23, no 1, article id 603Article in journal (Refereed) Published
Abstract [en]

Background. Emotional intelligence (EI), the ability to understand and regulate one’s and other’s emotions, has been linked to academic and clinical performance and stress management, making it an essential skill to develop during medical school. Nevertheless, uncertainty remains about the impact of medical education on EI, its association with sociodemographic factors, and the potential moderating role of gender. Therefore, this study aimed to explore levels of global EI among Swedish medical students based on their completed semesters while analyzing the potential moderator role of gender and identifying potential EI differences associated with age, gender, prior education, work experience, and previous experience working in a leadership position.

Methods: The participants were medical students in semesters 1, 3, 5, 7, 9, and 11 at a Swedish University. Participants answered the self-report Trait Emotional Intelligence Questionnaire - Short Form (TEIQue-SF) and demographic questions. For each participant, the mean global trait EI was calculated (range 1–7), and differences were compared based on semesters and sociodemographic factors. In addition, we investigated the relationship between semester and EI scores with gender as a moderator.

Results: Of the 663 invited medical students, 429 (65%) responded, including 269 women (62.7%), 157 men (36.6%), and 3 identifying as others (0.7%). The participants had a mean global trait EI score of 5.33. Final-year students demonstrated significantly higher global trait EI scores than first-year students, and gender did not have a moderating effect across semesters. Furthermore, students in the age group 25–29 years showed higher EI scores compared to those in the age group 21–24 years, while there were no significant differences in EI scores for older students (≥ 30 years) compared to other age groups. Higher EI scores were also positively associated with previous work-and leadership experiences. Gender and previous education did not significantly impact EI scores.

Conclusions. Our findings suggest that higher EI scores are associated with semesters of medical education, age, and previous work and leadership experience. Future longitudinal studies are needed to identify factors that could improve EI among medical students to design curricular activities aimed at supporting the EI of the next generation of physicians.

Place, publisher, year, edition, pages
BioMed Central (BMC), 2023
Keywords
Emotional intelligence (EI), Swedish medical students, Questionnaire
National Category
Pedagogy Educational Sciences
Identifiers
urn:nbn:se:umu:diva-214002 (URN)10.1186/s12909-023-04570-0 (DOI)001054312900002 ()37620811 (PubMedID)2-s2.0-85168663184 (Scopus ID)
Available from: 2023-09-01 Created: 2023-09-01 Last updated: 2025-04-24Bibliographically approved
Bitar, A., Aung, K. M., Wai, S. N. & Hammarström, M.-L. (2019). Vibrio cholerae derived outer membrane vesicles modulate the inflammatory response of human intestinal epithelial cells by inducing microRNA-146a. Scientific Reports, 9, Article ID 7212.
Open this publication in new window or tab >>Vibrio cholerae derived outer membrane vesicles modulate the inflammatory response of human intestinal epithelial cells by inducing microRNA-146a
2019 (English)In: Scientific Reports, E-ISSN 2045-2322, Vol. 9, article id 7212Article in journal (Refereed) Published
Abstract [en]

The small intestinal epithelium of Vibrio cholerae infected patients expresses the immunomodulatory microRNAs miR-146a and miR-155 at acute stage of disease. V. cholerae release outer membrane vesicles (OMVs) that serve as vehicles for translocation of virulence factors including V. cholerae cytolysin (VCC). The aim was to investigate whether OMVs, with and/or without VCC-cargo could be responsible for induction of microRNAs in intestinal epithelial cells and thereby contribute to immunomodulation. Polarized tight monolayers of T84 cells were challenged with OMVs of wildtype and a VCC deletion mutant of the non-O1/non-O139 (NOVC) V. cholerae strain V:5/04 and with soluble VCC. OMVs, with and without VCC-cargo, caused significantly increased levels of miR-146a. Increase was seen already after 2 hours challenge with OMVs and persisted after 12 hours. Challenge with soluble VCC caused significant increases in interleukin-8 (IL-8), tumour necrosis factor-α (TNF-α), CCL20, IL-1β, and IRAK2 mRNA levels while challenge with OMVs did not cause increases in expression levels of any of these mRNAs. These results suggest that V. cholerae bacteria release OMVs that induce miR-146a in order to pave the way for colonization by reducing the strength of an epithelial innate immune defence reaction and also preventing inflammation in the mucosa that factors like VCC can evoke.

Place, publisher, year, edition, pages
Nature Publishing Group, 2019
Keywords
Vibrio cholerae, intestinal epithelial cells, immunomodulation, microRNA, OMV, T84 monolayer, miR-146, miR-155, VCC, IL-8, TNF-a, IL-1b, IL-18, CCL20, IRAK2, inflammation
National Category
Immunology in the medical area
Research subject
Microbiology; Medicine; Molecular Biology
Identifiers
urn:nbn:se:umu:diva-147536 (URN)10.1038/s41598-019-43691-9 (DOI)000467543700027 ()31076615 (PubMedID)2-s2.0-85065655754 (Scopus ID)
Note

Originally included in thesis in manuscript form. 

Available from: 2018-05-07 Created: 2018-05-07 Last updated: 2022-09-15Bibliographically approved
Bitar, A. (2018). Vibrio cholerae modulates the immune defense of human gut mucosa. (Doctoral dissertation). Umeå: Umeå universitet
Open this publication in new window or tab >>Vibrio cholerae modulates the immune defense of human gut mucosa
2018 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The key function of innate immunity is to sense danger signals and initiate effective responses as a defense mechanism against pathogens. Simultaneously, effector responses must be regulated to avoid excessive inflammation with resulting tissue damage. microRNAs (miRNAs), are small endogenous molecules, that has recently gained attention as important regulatory elements in the human inflammation cascade. The control over host miRNA expression may represent a previously uncharacterized molecular strategy exploited by pathogens to mitigate innate host cell responses.

Vibrio cholerae is a Gram-negative bacterium that colonizes the human small intestine and causes life-threatening secretory diarrhea, essentially mediated by cholera toxin (CT). It is considered a non-invasive pathogen and does not cause clinical inflammation. Still, cholera is associated with inflammatory changes of the small intestine. Furthermore, CT-negative strains of V. cholerae cause gastroenteritis and are associated with extra-intestinal manifestations, suggesting that other virulence factors than CT are also involved in the pathogenesis.

The innate immune response to V. cholerae is poorly investigated and the potential role of miRNA in cholera had not been studied before. Therefore, this thesis explores the role of intestinal epithelial cells in response to V. cholerae infection with a focus on regulatory miRNA as a potential contributor to the pathogenesis. The in vivo material was small intestinal biopsies from patients suffering from V. cholerae infection. As an in vitro model for V. cholerae attack on intestinal epithelium, we used tight monolayers of T84 cells infected with V. cholerae and their released factors. We analyzed changes in levels of cytokines, immunomodulatory microRNA and their target genes.

We showed that miRNA-146a and miRNA-155 reached significantly elevated levels in the intestinal mucosa at acute stages of disease in V. cholerae infected patients and declined to normal levels at the convalescent stage. Low-grade inflammation was identified at the acute stage of V. cholerae infection, which correlated with elevated levels of regulatory miRNA. Furthermore, outer membrane vesicles (OMVs) released by the bacteria were shown to induce miR-146a and live bacteria induced miR-155 in intestinal epithelial cells. In addition, OMVs decreased epithelial permeability and caused mRNA suppression of pro-inflammatory cytokines, including immune cell attractant IL-8 and CLL20, and the inflammasome markers IL-1b and IL-18. These results propose that V. cholerae regulates the host expression of miRNA during infection and may set the threshold for activation of the intestinal epithelium.

Moreover, we showed that V. cholerae also harbors inflammatory-inducing capabilities, by secreting a pore-forming toxin, Vibrio cholerae cytolysin (VCC). By using genetically modified strains as well as soluble protein challenge experiments, VCC was found solely responsible for the increased epithelial permeability and induction of several pro-inflammatory cytokines in intestinal epithelial cells. In contrast to OMVs, VCC displayed strong upregulation of the pro-inflammatory cytokines IL-8, TNF-a, CCL20 and IL-1b and IRAK2, a key signaling molecule in the IL-1 inflammasome pathway. This suggest that VCC is an important virulence factor in the V. cholerae pathogenesis, particularly in CT-negative strains. Furthermore, we showed that the bacterium could control the inflammatory actions of VCC by secreting the PrtV protease, which degraded VCC and consequently abolished inflammation.  

In summary, we showed that V. cholerae harbors immunomodulating capabilities, both at the gene level, through induction of host regulatory miRNA, and at the protein level, through secretion of VCC and PrtV. These strategies may be relevant for V. cholerae to promote survival in the gut and cause successful infections in the human host.

Place, publisher, year, edition, pages
Umeå: Umeå universitet, 2018. p. 82
Series
Umeå University medical dissertations, ISSN 0346-6612 ; 1962
Keywords
Vibrio cholerae, intestinal epithelial cell, duodenum biopsy, acute cholera, immunomodulation, microRNA, OMV, cytokine, T84 monolayer, miR-146, miR-155, VCC, PrtV, hemolysis, IL-8, TNF-a, IL-1b, IL-18, CCL20, IRAK2, inflammation
National Category
Immunology in the medical area
Research subject
Microbiology; Immunology
Identifiers
urn:nbn:se:umu:diva-147538 (URN)978-91-7601-881-1 (ISBN)
Public defence
2018-06-05, Astrid Fagraeus hörsal A103, byggnad 6E, Umeå Universitet, Målpunkt R, byggnad 6B, våning 1, Norrlands universitetssjukhus, Umeå, 13:00 (English)
Opponent
Supervisors
Available from: 2018-05-15 Created: 2018-05-07 Last updated: 2024-07-02Bibliographically approved
Bitar, A., De, R., Melgar, S., Aung, K. M., Rahman, A., Qadri, F., . . . Hammarström, M.-L. (2017). Induction of immunomodulatory miR-146a and miR-155 in small intestinal epithelium of Vibrio cholerae infected patients at acute stage of cholera. PLOS ONE, 12(3), Article ID 0173817.
Open this publication in new window or tab >>Induction of immunomodulatory miR-146a and miR-155 in small intestinal epithelium of Vibrio cholerae infected patients at acute stage of cholera
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2017 (English)In: PLOS ONE, E-ISSN 1932-6203, Vol. 12, no 3, article id 0173817Article in journal (Refereed) Published
Abstract [en]

The potential immunomodulatory role of microRNAs in small intestine of patients with acute watery diarrhea caused by Vibrio cholerae O1 or enterotoxigenic Escherichia coli (ETEC) infection was investigated. Duodenal biopsies were obtained from study-participants at the acute (day 2) and convalescent (day 21) stages of disease, and from healthy individuals. Levels of miR-146a, miR-155 and miR-375 and target gene (IRAK1, TRAF6, CARD10) and 11 cytokine mRNAs were determined by qRT-PCR. The cellular source of microRNAs in biopsies was analyzed by in situ hybridization. The ability of V. cholerae bacteria and their secreted products to cause changes in microRNA- and mRNA levels in polarized tight monolayers of intestinal epithelial cells was investigated. miR-146a and miR-155 were expressed at significantly elevated levels at acute stage of V. cholerae infection and declined to normal at convalescent stage (P<0.009 versus controls; P = 0.03 versus convalescent stage, pairwise). Both microRNAs were mainly expressed in the epithelium. Only marginal down-regulation of target genes IRAK1 and CARD10 was seen and a weak cytokine-profile was identified in the acute infected mucosa. No elevation of microRNA levels was seen in ETEC infection. Challenge of tight monolayers with the wild type V. cholerae O1 strain C6706 and clinical isolates from two study-participants, caused significant increase in miR-155 and miR-146a by the strain C6706 (P<0.01). One clinical isolate caused reduction in IRAK1 levels (P<0.05) and none of the strains induced inflammatory cytokines. In contrast, secreted factors from these strains caused markedly increased levels of IL-8, IL-1β, and CARD10 (P<0.001), without inducing microRNA expression. Thus, miR-146a and miR-155 are expressed in the duodenal epithelium at the acute stage of cholera. The inducer is probably the V. cholerae bacterium. By inducing microRNAs the bacterium can limit the innate immune response of the host, including inflammation evoked by its own secreted factors, thereby decreasing the risk of being eliminated.

National Category
Microbiology in the medical area Immunology
Identifiers
urn:nbn:se:umu:diva-133013 (URN)10.1371/journal.pone.0173817 (DOI)000398945800031 ()28319200 (PubMedID)2-s2.0-85016003248 (Scopus ID)
Available from: 2017-03-28 Created: 2017-03-28 Last updated: 2024-07-02Bibliographically approved
Ou, G., Vaitkevicius, K., Bitar, A., Lindmark, B., Rompikuntal, P. K., Bhakdi, S., . . . Hammarström, M.-L. (2009). Vibrio cholerae cytolysin causes an inflammatory response in human intestinal cells that is modulated by the protease PrtV secreted by the same bacterium.
Open this publication in new window or tab >>Vibrio cholerae cytolysin causes an inflammatory response in human intestinal cells that is modulated by the protease PrtV secreted by the same bacterium
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2009 (English)Manuscript (preprint) (Other academic)
National Category
Immunology in the medical area
Identifiers
urn:nbn:se:umu:diva-18353 (URN)
Available from: 2009-02-04 Created: 2009-02-04 Last updated: 2024-07-02Bibliographically approved
Ou, G., Rompikuntal, P. K., Bitar, A., Lindmark, B., Vaitkevicius, K., Wai, S. N. & Hammarström, M.-L. (2009). Vibrio cholerae cytolysin causes an inflammatory response in human intestinal epithelial cells that is modulated by the PrtV protease. PLOS ONE, 4(11), Article ID e7806.
Open this publication in new window or tab >>Vibrio cholerae cytolysin causes an inflammatory response in human intestinal epithelial cells that is modulated by the PrtV protease
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2009 (English)In: PLOS ONE, E-ISSN 1932-6203, Vol. 4, no 11, article id e7806Article in journal (Refereed) Published
Abstract [en]

We suggest that VCC is capable of causing an inflammatory response characterized by increased permeability and production of IL-8 and TNF-alpha in tight monolayers. Pure VCC at a concentration of 160 ng/ml caused an inflammatory response that reached the magnitude of that caused by Vibrio-secreted factors, while higher concentrations caused epithelial cell death. The inflammatory response was totally abolished by treatment with PrtV. The findings suggest that low doses of VCC initiate a local immune defense reaction while high doses lead to intestinal epithelial lesions. Furthermore, VCC is indeed a substrate for PrtV and PrtV seems to execute an environment-dependent modulation of the activity of VCC that may be the cause of V. cholerae reactogenicity.

Place, publisher, year, edition, pages
San Francisco: Public Library of Science, 2009
National Category
Immunology in the medical area
Identifiers
urn:nbn:se:umu:diva-41945 (URN)10.1371/journal.pone.0007806 (DOI)000271721400007 ()19907657 (PubMedID)2-s2.0-70649091281 (Scopus ID)
Available from: 2011-04-04 Created: 2011-04-04 Last updated: 2024-07-02Bibliographically approved
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