23 results on '"Ben-Othman N"'
Search Results
2. In vivo conversion of adult α-cells into β-like cells: a new research avenue in the context of type 1 diabetes
- Author
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Courtney, M., Pfeifer, A., Al-Hasani, K., Gjernes, E., Vieira, A., Ben-Othman, N., and Collombat, P.
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- 2011
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3. β-Cell replacement as a treatment for type 1 diabetes: an overview of possible cell sources and current axes of research.
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Vieira, A., Courtney, M., Druelle, N., Avolio, F., Napolitano, T., Hadzic, B., Navarro-Sanz, S., Ben-Othman, N., and Collombat, P.
- Subjects
TYPE 1 diabetes ,STEM cells ,PANCREATIC beta cells ,HYPERGLYCEMIA ,HOMEOSTASIS - Abstract
To efficiently treat type 1 diabetes, exogenous insulin injections currently represent the main approach to counter chronic hyperglycaemia. Unfortunately, such a therapeutic approach does not allow for perfectly maintained glucose homeostasis and, in time, cardiovascular complications may arise. Therefore, seeking alternative/improved treatments has become a major health concern as an increasing proportion of type 2 diabetes patients also require insulin supplementation. Towards this goal, numerous laboratories have focused their research on β-cell replacement therapies. Herein, we will review the current state of this research area and describe the cell sources that could potentially be used to replenish the depleted β-cell mass in diabetic patients. [ABSTRACT FROM AUTHOR]
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- 2016
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4. O56 Implication de la kinase inflammatoire Tpl2 dans les effets délétères des macrophages sur la sensibilité à l’insuline des adipocytes
- Author
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Ceppo, F., Jager, J., Gremeaux, T., Ben Othman, N., Bezy, O., Vidal, H., Tran, A., Gual, P., Le Marchand-Brustel, Y., Cormont, M., and Tanti, J.-F.
- Published
- 2011
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5. Lipschütz ulcer following first dose of COVID-19 tozinameran vaccine: Report of a case and review of a World Health Organization pharmacovigilance database.
- Author
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Ewig E, Ben Othman N, Viard D, Gauci PA, Rocher F, and Drici MD
- Abstract
Lipschütz ulcer (LU) is a condition known for painful vulvar ulcers, typically affecting young women and often linked to infectious agents. Recent reports have indicated a potential connection between LU and COVID-19 vaccination, particularly after the second or booster doses. This study presents a case of LU following the first dose of tozinameran in a young woman who had a previous SARS-CoV-2 infection and investigates similar cases globally. An 18-year-old woman experienced vulvar pain and ulcers 2-days after her initial COVID-19 vaccine dose. After ruling out infections through serological tests, a diagnosis of LU was made, and her symptoms resolved after 10 days. A literature search and VigiBase® analysis revealed 11 cases of LU following COVID-19 vaccination, and 519 vulvovaginal ulcer cases associated with these vaccines were identified in Vigibase®, with a median onset of 2 days. Most LU cases occurred after the second dose or booster shots. The primary hypothesis for this association is a type 3 hypersensitivity reaction mediated by immune complexes, possibly triggered by prior exposure, as many cases occurred after the second dose. Interestingly, the presented case suggests that prior COVID-19 infection could serve as sensitization. In conclusion, this study highlights the potential occurrence of LU after the initial COVID-19 vaccine dose in young patients with prior COVID-19 infection. While the risk of recurrence after subsequent vaccinations or infections remains uncertain, the benefits of vaccination outweigh the risks. Clinicians and patients should be aware of this potential issue to make informed decisions regarding vaccination., (© 2024 The Author(s). International Journal of Gynecology & Obstetrics published by John Wiley & Sons Ltd on behalf of International Federation of Gynecology and Obstetrics.)
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- 2024
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6. Dental Adverse Effects of Anti-CD20 Therapies.
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Bartak H, Fareh T, Ben Othman N, Viard D, Cohen M, Rocher F, Ewig E, Drici MD, and Lebrun-Frenay C
- Abstract
Introduction: Over the past few years, anti-CD20 therapies like rituximab, ocrelizumab or ofatumumab have seen an increase in interest in the treatment of neurological autoimmune disorders such as multiple sclerosis (MS), neuromyelitis optica spectrum disorders (NMOSD), or resistant forms of generalized myasthenia gravis (MG). They are generally well-tolerated, but recent reports have highlighted severe dental disorders in patients undergoing anti-CD20 therapies. The aim was to describe a series of cases and to compare with the available scientific literature., Methods: We reviewed 6 patient cases with dental disorders during anti-CD20 therapy that were reported to the pharmacovigilance center. A disproportionality analysis was also conducted on Vigibase® for each anti-CD20 and each adverse effect described in the cases., Results: Six cases of dental and gingival conditions in relatively young patients were reported (median age: 40.5 years old [min: 34; max: 79]). Oral conditions were developed in four patients with MS treated with ocrelizumab and in two patients receiving rituximab (one patient with MG and one with NMOSD). The onset of oral conditions ranged from 10 days to 2 years after treatment initiation. Notably, all patients treated with ocrelizumab experienced gingival recession. Various dental pathologies were observed, including tooth loss, dental pain, caries, brittle teeth, dental fractures, dental abscesses, and periodontitis. Analysis of Vigibase® revealed 284 worldwide cases of dental and gingival conditions under ocrelizumab, 386 cases under rituximab, and 80 under ofatumumab. Significant associations were found between these therapies and dental pathologies, particularly tooth abscesses and infections., Conclusion: To our knowledge, this is the first case series reporting dental conditions developed in patients long-term treated with anti-CD20 treatments. This issue, literature data, and Vigilyze® analysis might be considered a safety signal that necessitates being confirmed with more robust data, such as a retrospective study with a control group. Meanwhile, proactive measures are essential like frequent dental checkups and dental hygienic measures to prevent oral health problems associated with anti-CD20 therapies., (© 2024. The Author(s).)
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- 2024
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7. Drug-Associated Parosmia: New Perspectives from the WHO Safety Database.
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Merino D, Gérard AO, Thümmler S, Ben Othman N, Viard D, Rocher F, Destere A, Van Obberghen EK, and Drici MD
- Abstract
Parosmia is a qualitative distortion of smell perception. Resulting from central causes, sinonasal diseases, and infections, parosmia has also been associated with medications. Therefore, we aimed to investigate potential signals for drugs associated with parosmia. VigiBase
® (the WHO pharmacovigilance database) was queried for all reports of "Parosmia" (MedDRA Preferred Term), registered up to 23 January 2022. Disproportionality analysis relied on the reporting odds ratio and the information component. A signal is detected when the lower end of the 95% confidence interval of the information component is positive. We found 14,032 reports of parosmia, with a median patient age of 53 years. Most reported drugs were antiinfectives, among which COVID-19 vaccines accounted for 27.1% of reports. Antibiotics and corticosteroids were involved in 6.8% and 4.6% of reports. Significant disproportionate reporting was detected for corticosteroids, antibiotics, drugs used in nicotine dependence, COVID-19 and HPV vaccines, serotonin-norepinephrine reuptake inhibitors (SNRI), and incretin mimetics. We suggest potential safety signals involving nicotine replacement therapies and vaccines. We also highlight the potential role of less suspected classes, such as SNRIs and incretin mimetics. An iatrogenic etiology should be evoked when parosmia occurs, especially in the elderly.- Published
- 2022
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8. Medications as a Trigger of Sleep-Related Eating Disorder: A Disproportionality Analysis.
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Merino D, Gérard AO, Van Obberghen EK, Ben Othman N, Ettore E, Giordana B, Viard D, Rocher F, Destere A, Benoit M, and Drici MD
- Abstract
Sleep-related eating disorder (SRED) is a parasomnia with recurrent, involuntary, amnestic eating episodes during sleep. There is growing evidence of the association between SRED and medications. Therefore, we aimed to rank drugs showing the strongest association. VigiBase® (WHO pharmacovigilance database) was queried for all reports of “Sleep-related eating disorder”. Disproportionality analysis relied on the Reporting Odds Ratio, with its 95% Confidence Interval (CI), and the Information Component. Our VigiBase® query yielded 676 cases of drug-associated SRED. Reports mostly involved zolpidem (243, 35.9%), sodium oxybate (185, 27.4%), and quetiapine (97, 14.3%). Significant disproportionality was found for 35 medications, including zolpidem (387.6; 95%CI 331.2−453.7), sodium oxybate (204.2; 95%CI 172.4−241.8), suvorexant (67.3; 95%CI 38.0−119.2), quetiapine (53.3; 95%CI 43.0−66.1), and several psychostimulants and serotonin-norepinephrine reuptake inhibitors (SNRIs). Patients treated with nonbenzodiazepines or SNRIs were significantly older (mean age: 49.0 vs. 37.5; p < 0.001) and their SRED were more likely to be serious (62.6% vs. 51.4%; p = 0.014) than patients treated with sodium oxybate or psychostimulants. Psychotropic drugs are involved in almost all reports. In patients with SRED, an iatrogenic trigger should be searched for.
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- 2022
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9. Adverse Drug Reactions of Olanzapine, Clozapine and Loxapine in Children and Youth: A Systematic Pharmacogenetic Review.
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Merino D, Fernandez A, Gérard AO, Ben Othman N, Rocher F, Askenazy F, Verstuyft C, Drici MD, and Thümmler S
- Abstract
Children and youth treated with antipsychotic drugs (APs) are particularly vulnerable to adverse drug reactions (ADRs) and prone to poor treatment response. In particular, interindividual variations in drug exposure can result from differential metabolism of APs by cytochromes, subject to genetic polymorphism. CYP1A2 is pivotal in the metabolism of the APs olanzapine, clozapine, and loxapine, whose safety profile warrants caution. We aimed to shed some light on the pharmacogenetic profiles possibly associated with these drugs' ADRs and loss of efficacy in children and youth. We conducted a systematic review relying on four databases, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 recommendations and checklist, with a quality assessment. Our research yielded 32 publications. The most frequent ADRs were weight gain and metabolic syndrome (18; 56.3%), followed by lack of therapeutic effect (8; 25%) and neurological ADRs (7; 21.8%). The overall mean quality score was 11.3/24 (±2.7). In 11 studies (34.3%), genotyping focused on the study of cytochromes. Findings regarding possible associations were sometimes conflicting. Nonetheless, cases of major clinical improvement were fostered by genotyping. Yet, CYP1A2 remains poorly investigated. Further studies are required to improve the assessment of the risk-benefit balance of prescription for children and youth treated with olanzapine, clozapine, and/or loxapine.
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- 2022
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10. COVID-19 Vaccine-Associated Transient Global Amnesia: A Disproportionality Analysis of the WHO Safety Database.
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Merino D, Gérard AO, Van Obberghen EK, Ben Othman N, Ettore E, Giordana B, Viard D, Rocher F, Destere A, Benoit M, and Drici MD
- Abstract
Coronavirus disease 2019 (COVID-19) spread rapidly, resulting in a global pandemic for which vaccines were quickly developed. As their safety continues to be monitored, cases of transient global amnesia (TGA) following mRNA vaccination with elasomeran have been reported. TGA is characterized by sudden onset of anterograde amnesia with preservation of other cognitive functions and resolution within 24 h. We aimed to investigate the potential link of TGA with COVID-19 vaccines. We queried the World Health Organization VigiBase
® for all reports of "Transient global amnesia", up to 6 December 2021. Disproportionality analysis relied on the Reporting Odds Ratio (ROR) with its 95% Confidence Interval (CI) and the Information Component (IC). A positive lower end of the 95% CI of the IC (IC025) is used to statistically detect a signal. Of all TGA cases, 289 were associated with a COVID-19 vaccine, representing the most frequent association. Tozinameran was mostly represented (147, 50.8%), followed by AZD1222 (69, 23,8%), elasomeran (60, 20.8%), and JNJ-78436735 (12, 4.2%). With an IC025 > 0, COVID-19 vaccines showed a significant ROR (5.1; 95%CI 4.4-6.0). Tozinameran reached the strongest ROR (4.6; 95%CI 3.9-5.0), followed by elasomeran (4.4; 95%CI 3.4-6.0), AZD1222 (3.8; 95%CI 3.0-5.0), and JNJ-78436735 (3.7; 95%CI 2.1-6.0). Our analysis of COVID-19 vaccines-related TGA reports shows significant disproportionality. Cerebrovascular, inflammatory, or migrainous mechanisms may underlie this association. Yet, numerous confounding factors cannot be tackled with this approach, and causality cannot be ascertained. The identification of this trigger of TGA may help the clinician in his etiological research., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Merino, Gérard, Van Obberghen, Ben Othman, Ettore, Giordana, Viard, Rocher, Destere, Benoit and Drici.)- Published
- 2022
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11. Advanced oxidation process and biological treatments for table olive processing wastewaters: constraints and a novel approach to integrated recycling process: a review.
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Ayed L, Asses N, Chammem N, Ben Othman N, and Hamdi M
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- Biodegradation, Environmental, Oxidation-Reduction, Waste Disposal, Fluid methods, Olea chemistry, Recycling methods, Wastewater chemistry
- Abstract
Table olive processing wastewaters constitute a dangerous environmental problem in the Mediterranean countries because of their large volumes, high organic matter and salt concentration. The quantity and the characteristics of wastewaters produced, and thus, their environmental impact, varied depending on the season, varieties, soil and process employed. Several chemicals, biological and combined technologies have proven effective at bringing down organic pollution and toxicity of these effluents. Advanced oxidation processes have recognized as highly efficient treatments for the degradation of organic matter. Nonetheless, complete mineralization is generally expensive without salt removal. Biological processes are the most environmentally compatible and least-expensive treatment methods, but these operations do not always provide satisfactory results. This article surveys the current available technologies and suggests an effective, cheaper alternative for the recycling and the valorization of green table olives wastewaters.
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- 2017
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12. GABA triggers pancreatic β-like cell neogenesis.
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Vieira A, Ben-Othman N, and Collombat P
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- gamma-Aminobutyric Acid, Homeodomain Proteins, Paired Box Transcription Factors
- Published
- 2017
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13. GABA signaling stimulates α-cell-mediated β-like cell neogenesis.
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Napolitano T, Avolio F, Vieira A, Ben-Othman N, Courtney M, Gjernes E, Hadzic B, Druelle N, Navarro Sanz S, Silvano S, Mansouri A, and Collombat P
- Abstract
Diabetes is a chronic and progressing disease, the number of patients increasing exponentially, especially in industrialized countries. Regenerating lost insulin-producing cells would represent a promising therapeutic alternative for most diabetic patients. To this end, using the mouse as a model, we reported that GABA, a food supplement, could induce insulin-producing beta-like cell neogenesis offering an attractive and innovative approach for diabetes therapeutics.
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- 2017
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14. Long-Term GABA Administration Induces Alpha Cell-Mediated Beta-like Cell Neogenesis.
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Ben-Othman N, Vieira A, Courtney M, Record F, Gjernes E, Avolio F, Hadzic B, Druelle N, Napolitano T, Navarro-Sanz S, Silvano S, Al-Hasani K, Pfeifer A, Lacas-Gervais S, Leuckx G, Marroquí L, Thévenet J, Madsen OD, Eizirik DL, Heimberg H, Kerr-Conte J, Pattou F, Mansouri A, and Collombat P
- Subjects
- Animals, Basic Helix-Loop-Helix Transcription Factors, Cell Differentiation drug effects, Diabetes Mellitus chemically induced, Diabetes Mellitus metabolism, Diabetes Mellitus pathology, Glucagon-Secreting Cells drug effects, Humans, Islets of Langerhans cytology, Male, Mice, Nerve Tissue Proteins, Rats, Rats, Wistar, gamma-Aminobutyric Acid pharmacology, Diabetes Mellitus drug therapy, Glucagon-Secreting Cells cytology, Insulin-Secreting Cells cytology, gamma-Aminobutyric Acid administration & dosage
- Abstract
The recent discovery that genetically modified α cells can regenerate and convert into β-like cells in vivo holds great promise for diabetes research. However, to eventually translate these findings to human, it is crucial to discover compounds with similar activities. Herein, we report the identification of GABA as an inducer of α-to-β-like cell conversion in vivo. This conversion induces α cell replacement mechanisms through the mobilization of duct-lining precursor cells that adopt an α cell identity prior to being converted into β-like cells, solely upon sustained GABA exposure. Importantly, these neo-generated β-like cells are functional and can repeatedly reverse chemically induced diabetes in vivo. Similarly, the treatment of transplanted human islets with GABA results in a loss of α cells and a concomitant increase in β-like cell counts, suggestive of α-to-β-like cell conversion processes also in humans. This newly discovered GABA-induced α cell-mediated β-like cell neogenesis could therefore represent an unprecedented hope toward improved therapies for diabetes., (Copyright © 2017 Elsevier Inc. All rights reserved.)
- Published
- 2017
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15. Pax4 acts as a key player in pancreas development and plasticity.
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Napolitano T, Avolio F, Courtney M, Vieira A, Druelle N, Ben-Othman N, Hadzic B, Navarro S, and Collombat P
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- Animals, Homeodomain Proteins genetics, Homeodomain Proteins metabolism, Humans, Mice, Paired Box Transcription Factors genetics, Paired Box Transcription Factors metabolism, Pancreas embryology, Pancreas metabolism, Pancreas physiology, Homeodomain Proteins physiology, Paired Box Transcription Factors physiology
- Abstract
The embryonic development of the pancreas is orchestrated by a complex and coordinated transcription factor network. Neurogenin3 (Neurog3) initiates the endocrine program by activating the expression of additional transcription factors driving survival, proliferation, maturation and lineage allocation of endocrine precursors. Among the direct targets of Neurog3, Pax4 appears as one of the key regulators of β-cell specification. Indeed, mice lacking Pax4 die a few days postpartum, as they develop severe hyperglycemia due to the absence of mature pancreatic β-cells. Pax4 also directly regulates the expression of Arx, a gene that plays a crucial role in α-cell specification. Comparative analysis of Pax4 and Arx mutants, as well as Arx/Pax4 double mutants, showed that islet subtype destiny is mainly directed by cross-repression of the Pax4 and Arx factors. Importantly, the ectopic expression of Pax4 in α-cells was found sufficient to induce their neogenesis and conversion into β-like cells, not only during development but also in adult rodents. Therefore, differentiated endocrine α-cells can be considered as a putative source for insulin-producing β-like cells. These findings have clearly widened our understanding regarding pancreatic development, but they also open new research avenues in the context of diabetes research., (Copyright © 2015 Elsevier Ltd. All rights reserved.)
- Published
- 2015
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16. Induction of multiple cycles of pancreatic β-cell replacement.
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Pfeifer A, Courtney M, Ben-Othman N, Al-Hasani K, Gjernes E, Vieira A, Druelle N, Avolio F, Faurite B, Mansouri A, and Collombat P
- Subjects
- Animals, Diabetes Mellitus, Experimental metabolism, Diabetes Mellitus, Experimental pathology, Diabetes Mellitus, Type 1 metabolism, Diabetes Mellitus, Type 1 pathology, Epithelial-Mesenchymal Transition, Homeodomain Proteins metabolism, Humans, Insulin-Secreting Cells metabolism, Mice, Mice, Transgenic, Paired Box Transcription Factors metabolism, Cell Cycle, Insulin-Secreting Cells pathology
- Published
- 2013
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17. The inactivation of Arx in pancreatic α-cells triggers their neogenesis and conversion into functional β-like cells.
- Author
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Courtney M, Gjernes E, Druelle N, Ravaud C, Vieira A, Ben-Othman N, Pfeifer A, Avolio F, Leuckx G, Lacas-Gervais S, Burel-Vandenbos F, Ambrosetti D, Hecksher-Sorensen J, Ravassard P, Heimberg H, Mansouri A, and Collombat P
- Subjects
- Animals, Diabetes Mellitus, Type 1 pathology, Diabetes Mellitus, Type 1 therapy, Disease Models, Animal, Gene Expression Regulation, Glucagon genetics, Glucagon metabolism, Glucagon-Secreting Cells metabolism, Glucagon-Secreting Cells pathology, Homeodomain Proteins antagonists & inhibitors, Homeodomain Proteins biosynthesis, Humans, Insulin-Secreting Cells cytology, Islets of Langerhans metabolism, Islets of Langerhans pathology, Mice, Transgenic, Paired Box Transcription Factors genetics, Transcription Factors antagonists & inhibitors, Transcription Factors biosynthesis, Cell Differentiation, Diabetes Mellitus, Type 1 genetics, Homeodomain Proteins genetics, Insulin-Secreting Cells metabolism, Transcription Factors genetics
- Abstract
Recently, it was demonstrated that pancreatic new-born glucagon-producing cells can regenerate and convert into insulin-producing β-like cells through the ectopic expression of a single gene, Pax4. Here, combining conditional loss-of-function and lineage tracing approaches, we show that the selective inhibition of the Arx gene in α-cells is sufficient to promote the conversion of adult α-cells into β-like cells at any age. Interestingly, this conversion induces the continuous mobilization of duct-lining precursor cells to adopt an endocrine cell fate, the glucagon(+) cells thereby generated being subsequently converted into β-like cells upon Arx inhibition. Of interest, through the generation and analysis of Arx and Pax4 conditional double-mutants, we provide evidence that Pax4 is dispensable for these regeneration processes, indicating that Arx represents the main trigger of α-cell-mediated β-like cell neogenesis. Importantly, the loss of Arx in α-cells is sufficient to regenerate a functional β-cell mass and thereby reverse diabetes following toxin-induced β-cell depletion. Our data therefore suggest that strategies aiming at inhibiting the expression of Arx, or its molecular targets/co-factors, may pave new avenues for the treatment of diabetes., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2013
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18. [Reprogramming pancreatic cells to β cells].
- Author
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Vieira A, Druelle N, Courtney M, Avolio F, Ben-Othman N, Pfeifer A, Gjernes E, Faurite B, and Collombat P
- Subjects
- Acinar Cells cytology, Diabetes Mellitus, Type 1 surgery, Humans, Insulin-Secreting Cells physiology, Islets of Langerhans Transplantation, Pancreatic Ducts cytology, Regeneration, Tissue Donors supply & distribution, Cell Differentiation, Diabetes Mellitus, Type 1 therapy, Insulin-Secreting Cells cytology, Pancreas cytology
- Abstract
Type 1 diabetes (T1DM) is a common metabolic disorder affecting an ever-increasing number of patients worldwide. T1DM is caused by the selective destruction of pancreatic insulin-producing β-cells by the immune system. Such loss results in chronic hyperglycemia and could induce a number of cardio-vascular complications. Despite the classical insulin-based therapy, compared to healthy people, patients with T1DM display a shortened life expectancy due to the treatment's inability to strictly regulate glycemic levels. An alternative therapy involves pancreatic islet transplantation but the shortage of donors and the required immuno-suppressive treatments limit the widespread use of this approach. Therefore, the search of new approaches to generate functional β-cells is of growing interest. In this review, we describe several novel strategies aiming at the conversion of diverse pancreatic cells into β-cells, such as acinar, ductal, and endocrine cells. Clearly, such promising results could open new research avenues in the context of type 1 diabetes research., (© 2013 médecine/sciences – Inserm.)
- Published
- 2013
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19. Adult duct-lining cells can reprogram into β-like cells able to counter repeated cycles of toxin-induced diabetes.
- Author
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Al-Hasani K, Pfeifer A, Courtney M, Ben-Othman N, Gjernes E, Vieira A, Druelle N, Avolio F, Ravassard P, Leuckx G, Lacas-Gervais S, Ambrosetti D, Benizri E, Hecksher-Sorensen J, Gounon P, Ferrer J, Gradwohl G, Heimberg H, Mansouri A, and Collombat P
- Subjects
- Animals, Basic Helix-Loop-Helix Transcription Factors genetics, Basic Helix-Loop-Helix Transcription Factors metabolism, Blood Glucose analysis, Cell Differentiation, Cell Lineage, Cell Movement, Diabetes Mellitus, Experimental genetics, Epithelial-Mesenchymal Transition, Gene Expression Regulation, Glucagon-Secreting Cells metabolism, Glucagon-Secreting Cells pathology, Homeodomain Proteins genetics, Homeodomain Proteins metabolism, Hypertrophy metabolism, Hypertrophy pathology, Insulin-Secreting Cells pathology, Mice, Nerve Tissue Proteins genetics, Nerve Tissue Proteins metabolism, Paired Box Transcription Factors genetics, Paired Box Transcription Factors metabolism, Pancreatic Ducts drug effects, Pancreatic Ducts metabolism, Pancreatic Ducts pathology, Streptozocin, Cellular Reprogramming, Diabetes Mellitus, Experimental metabolism, Insulin-Secreting Cells metabolism
- Abstract
It was recently demonstrated that embryonic glucagon-producing cells in the pancreas can regenerate and convert into insulin-producing β-like cells through the constitutive/ectopic expression of the Pax4 gene. However, whether α cells in adult mice display the same plasticity is unknown. Similarly, the mechanisms underlying such reprogramming remain unclear. We now demonstrate that the misexpression of Pax4 in glucagon(+) cells age-independently induces their conversion into β-like cells and their glucagon shortage-mediated replacement, resulting in islet hypertrophy and in an unexpected islet neogenesis. Combining several lineage-tracing approaches, we show that, upon Pax4-mediated α-to-β-like cell conversion, pancreatic duct-lining precursor cells are continuously mobilized, re-express the developmental gene Ngn3, and successively adopt a glucagon(+) and a β-like cell identity through a mechanism involving the reawakening of the epithelial-to-mesenchymal transition. Importantly, these processes can repeatedly regenerate the whole β cell mass and thereby reverse several rounds of toxin-induced diabetes, providing perspectives to design therapeutic regenerative strategies., (Copyright © 2013 Elsevier Inc. All rights reserved.)
- Published
- 2013
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20. From pancreatic islet formation to beta-cell regeneration.
- Author
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Ben-Othman N, Courtney M, Vieira A, Pfeifer A, Druelle N, Gjernes E, Faurite B, Avolio F, and Collombat P
- Subjects
- Animals, Humans, Islets of Langerhans physiology, Mice, Cellular Reprogramming, Insulin-Secreting Cells cytology, Islets of Langerhans cytology, Regeneration physiology
- Abstract
Diabetes mellitus represents a major healthcare burden and, due to the increasing prevalence of type I diabetes and the complications arising from current treatments, other alternative therapies must be found. Type I diabetes arises as a result of a cell-mediated autoimmune destruction of insulin producing pancreatic β-cells. Thus, a cell replacement therapy would be appropriate, using either in vitro or in vivo cell differentiation/reprogramming from different cell sources. Increasing our understanding of the molecular mechanisms controlling endocrine cell specification during pancreas morphogenesis and gaining further insight into the complex transcriptional network and signaling pathways governing β-cell development should facilitate efforts to achieve this ultimate goal, that is to regenerate insulin-producing β-cells. This review will therefore describe briefly the genetic program underlying mouse pancreas development and present new insights regarding β-cell regeneration., (Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.)
- Published
- 2013
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21. From pancreas morphogenesis to β-cell regeneration.
- Author
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Avolio F, Pfeifer A, Courtney M, Gjernes E, Ben-Othman N, Vieira A, Druelle N, Faurite B, and Collombat P
- Subjects
- Animals, Cell Dedifferentiation physiology, Cell Differentiation physiology, Diabetes Mellitus, Type 1 surgery, Embryonic Stem Cells cytology, Embryonic Stem Cells transplantation, Humans, Insulin-Secreting Cells cytology, Insulin-Secreting Cells transplantation, Pancreas cytology, Pancreas growth & development, Regenerative Medicine methods, Embryonic Stem Cells physiology, Insulin-Secreting Cells physiology, Pancreas embryology, Regeneration
- Abstract
Type 1 diabetes is a metabolic disease resulting in the selective loss of pancreatic insulin-producing β-cells and affecting millions of people worldwide. The side effects of diabetes are varied and include cardiovascular, neuropathologic, and kidney diseases. Despite the most recent advances in diabetes care, patients suffering from type 1 diabetes still display a shortened life expectancy compared to their healthy counterparts. In an effort to improve β-cell-replacement therapies, numerous approaches are currently being pursued, most of these aiming at finding ways to differentiate stem/progenitor cells into β-like cells by mimicking embryonic development. Unfortunately, these efforts have hitherto not allowed the generation of fully functional β-cells. This chapter summarizes recent findings, allowing a better insight into the molecular mechanisms underlying the genesis of β-cells during the course of pancreatic morphogenesis. Furthermore, a focus is made on new research avenues concerning the conversion of pre-existing pancreatic cells into β-like cells, such approaches holding great promise for the development of type 1 diabetes therapies., (© 2013 Elsevier Inc. All rights reserved.)
- Published
- 2013
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22. Characterization of Lactobacillus isolates from fermented olives and their bacteriocin gene profiles.
- Author
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Hurtado A, Ben Othman N, Chammem N, Hamdi M, Ferrer S, Reguant C, Bordons A, and Rozès N
- Subjects
- Bacteriocins metabolism, Fermentation, Lactobacillus classification, Lactobacillus genetics, Molecular Sequence Data, Olea metabolism, Phylogeny, Bacteriocins genetics, Lactobacillus isolation & purification, Lactobacillus metabolism, Olea microbiology
- Abstract
Near one hundred isolates of Lactobacillus paraplantarum, Lactobacillus pentosus and Lactobacillus plantarum from table olives were studied. Strains were genotyped by rep-PCR. Although the technique failed to differentiate some isolates at the species level, it proved a robust and easy procedure that could be useful for distinguishing between related strains of L. paraplantarum, L. pentosus and L. plantarum from a large pool of unrelated strains of these species. A PCR-based screening revealed the presence of the plantaricin encoding genes plnA, plnB, plnC, plnD, plnE/F, plnF, plnI, plnJ, plnK, plnG and plnN in most isolates of the three species. Sequences of bacteriocin genes present in L. paraplantarum and L. pentosus were homologous to L. plantarum genes. Through a discriminating analysis of the bacteriocin gene profiles, it was possible to establish a relationship between the origin of isolation and the LAB isolates, regardless of species., (Copyright © 2011 Elsevier Ltd. All rights reserved.)
- Published
- 2011
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23. Tunisian table olive phenolic compounds and their antioxidant capacity.
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Ben Othman N, Roblain D, Thonart P, and Hamdi M
- Subjects
- Chromans, Diet, Nutritive Value, Phenylethyl Alcohol analogs & derivatives, Phenylethyl Alcohol analysis, Species Specificity, Tunisia, Vanillic Acid analysis, Antioxidants analysis, Fruit chemistry, Olea chemistry, Phenols analysis
- Abstract
For the 1st time, 4 olive cultivars, the Meski, Chemlali, Besbessi, and Tounsi, from the Tunisian market were investigated to evaluate the phenolic compounds' contribution in nutritional value of table olives. From the Meski cultivar, we have chosen 4 different samples to evaluate differences within the same cultivar. Basic characteristics and total phenolic content were evaluated in flesh and kernel. The highest value of flesh phenolic content was observed in sample M4 of the Meski cultivar; however, the lowest value was observed in the Besbessi cultivar and they were 1801 and 339 mg GA/100 g dry weight, respectively. The main simple phenolic compounds identified in flesh extracts are hydroxytyrosol, tyrosol, and vanillic acid. Oleuropein was not detected in any samples. The antioxidant activity of Tunisian olive flesh varies between 212 and 462 muM TEAC/g of dry weight. Antioxidant activity of olives was related to their phenolic content but we found a low correlation between phenolic content and TEAC.
- Published
- 2008
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