A nanobody-based tracer targeting DPP6 for non-invasive imaging of human pancreatic endocrine cells

There are presently no reliable ways to quantify endocrine cell mass (ECM) in vivo, which prevents an accurate understanding of the progressive beta cell loss in diabetes or following islet transplantation. To address this unmet need, we coupled RNA sequencing of human pancreatic islets to a systems biology approach to identify new biomarkers of the endocrine pancreas. Dipeptidyl-Peptidase 6 (DPP6) was identified as a target whose mRNA expression is at least 25-fold higher in human pancreatic islets as compared to surrounding tissues and is not changed by proinflammatory cytokines. At the protein level, DPP6 localizes only in beta and alpha cells within the pancreas. We next generated a high-affinity camelid single-domain antibody (nanobody) targeting human DPP6. The nanobody was radiolabelled and in vivo SPECT/CT imaging and biodistribution studies were performed in immunodeficient mice that were either transplanted with DPP6-expressing Kelly neuroblastoma cells or insulin-producing human EndoC-βH1 cells. The human DPP6-expressing cells were clearly visualized in both models. In conclusion, we have identified a novel beta and alpha cell biomarker and developed a tracer for in vivo imaging of human insulin secreting cells. This provides a useful tool to non-invasively follow up intramuscularly implanted insulin secreting cells

Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study

Background: Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world. Methods: This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231. Findings: Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p < 0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05–2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p < 0·001). Interpretation: Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication

Windei, the Drosophila Homolog of mAM/MCAF1, Is an Essential Cofactor of the H3K9 Methyl Transferase dSETDB1/Eggless in Germ Line Development

The epigenetic regulation of gene expression by the covalent modification of histones is a fundamental mechanism required for the proper differentiation of germ line cells during development. Trimethylation of histone 3 lysine 9 (H3K9me3) leads to chromatin silencing and the formation of heterochromatin by recruitment of heterochromatin protein 1 (HP1). dSETDB1/Eggless (Egg), the ortholog of the human methyltransferase SETDB1, is the only essential H3K9 methyltransferase in Drosophila and is required for H3K9 trimethylation in the female germ line. Here we show that Windei (Wde), the Drosophila homolog of mouse mAM and human MCAF1, is an essential cofactor of Egg required for its nuclear localization and function in female germ line cells. By deletion analysis combined with coimmunoprecipitation, we have identified the protein regions in Wde and Egg that are necessary and sufficient for the interaction between the two proteins. We furthermore identified a region of Egg that gets covalently modified by SUMOylation, which may facilitate the formation of higher order chromatin-modifying complexes. Together with Egg, Wde localizes to euchromatin, is enriched on chromosome 4, and binds to the Painting of fourth (POF) protein. Our data provide the first genetic and phenotypic analysis of a mAM/MCAF1 homolog in a model organism and demonstrate its essential function in the survival of germ line cells

Immature Cryopreserved Ovary Restores Puberty and Fertility in Mice without Alteration of Epigenetic Marks

BACKGROUND: Progress in oncology could improve survival rate in children, but would probably lead to impaired fertility and puberty. In pre-pubertal girls, the only therapeutic option is the cryopreservation of one ovary. Three births have been reported after reimplantation of cryopreserved mature ovary. Conversely, reimplantation of ovary preserved before puberty (defined as immature ovary) has never been performed in humans. METHODOLOGY/PRINCIPAL FINDINGS: In order to analyze ovarian function, we performed transplantation using fresh or cryopreserved immature grafts in pre-pubertal or adult mice. Puberty as well as cyclic hormonal activity was restored. All follicle populations were present although a significant reduction in follicle density was observed with or without cryopreservation. Although fertility was restored, the graft is of limited life span. Because ex vivo ovary manipulation and cryopreservation procedure, the status of genomic imprinting was investigated. Methylation status of the H19 and Lit1 Imprinting Control Regions in kidney, muscle and tongue of offsprings from grafted mice does not show significant alteration when compared to those of unoperated mice. CONCLUSIONS/SIGNIFICANCE: These results demonstrate that immature ovarian grafting can restore spontaneous puberty and fertility. However, these data suggest that follicle depletion leads to premature ovarian failure. This study addresses the very important epigenetics issue, and provides valuable information to the study of ovarian transplantation suggesting that these procedures do not perturb normal epigenetics marks. These results are highly relevant to the reimplantation question of immature cortex in women

Global economic burden of unmet surgical need for appendicitis

Background: There is a substantial gap in provision of adequate surgical care in many low-and middle-income countries. This study aimed to identify the economic burden of unmet surgical need for the common condition of appendicitis. Methods: Data on the incidence of appendicitis from 170 countries and two different approaches were used to estimate numbers of patients who do not receive surgery: as a fixed proportion of the total unmet surgical need per country (approach 1); and based on country income status (approach 2). Indirect costs with current levels of access and local quality, and those if quality were at the standards of high-income countries, were estimated. A human capital approach was applied, focusing on the economic burden resulting from premature death and absenteeism. Results: Excess mortality was 4185 per 100 000 cases of appendicitis using approach 1 and 3448 per 100 000 using approach 2. The economic burden of continuing current levels of access and local quality was US $92 492 million using approach 1 and$73 141 million using approach 2. The economic burden of not providing surgical care to the standards of high-income countries was $95 004 million using approach 1 and$75 666 million using approach 2. The largest share of these costs resulted from premature death (97.7 per cent) and lack of access (97.0 per cent) in contrast to lack of quality. Conclusion: For a comparatively non-complex emergency condition such as appendicitis, increasing access to care should be prioritized. Although improving quality of care should not be neglected, increasing provision of care at current standards could reduce societal costs substantially

Human embryonic pancreas development in a ex vivo / in vivo model

Au-delà de l’intérêt cognitif de la démarche, la compréhension des mécanismes qui régissent le développement pancréatique humain reste la clé pour décrypter les acteurs physiopathologiques des maladies du pancréas et pour développer des approches thérapeutiques innovantes. En outre, alors que la cellule bêta de rongeurs et la cellule bêta humaine partagent un grand nombre de similitudes, certaines données indiquent également des différences marquées entre les espèces. L'absence de systèmes expérimentaux robustes , à partir de matériel humain, n'a pas permis un examen détaillé du développement pancréatique humain jusqu’à présent. Dans le laboratoire, il a été précédemment validé un modèle de xénogreffe de pancréas immature humain sous la capsule rénale de souris immuno-incompétentes SCID. Il a été démontré que celui-ci permettait de récapituler l’ensemble des étapes du développement endocrine humain. Néanmoins le site de greffe limitait les possibilités de modifier ce développement, notamment par infection virale. Dans ce travail, nous avons développé et validé un nouveau site de greffe dans le muscle squelettique, plus simple et plus superficiel. En outre, nous démontrons qu’il est possible de créer un pancréas humain partiellement transgénique in vivo en réalisant du transfert de gènes médié par des lentivirus, après injection directe de la solution virale dans le greffon. Ce modèle de greffe dans le muscle est une nouvelle approche permettant d’envisager des études longitudinales, dans lesquelles il serait possible d’étudier la régulation de certains gènes ou le devenir de certaines lignées marquées par des gènes rapporteurs apportés par le virus à différents stades de développement.Whilst sporadic human genetic studies have permitted some comparisons between rodent and human pancreatic development, the lack of a robust experimental system has not permitted detailed examination of human pancreatic development. We previously developed a xenograft model of immature human fetal pancreas grafted under the kidney capsule of immune-incompetent mice, which allowed the development of human pancreatic beta cells. Here, we compared the development of human and murine fetal pancreatic grafts either under skeletal muscle epimysium or under the renal capsule. We demonstrated that human pancreatic beta cell development occurs) both by differentiation of pancreatic progenitors and by proliferation of developing beta cells. The superficial location of the skeletal muscle graft and its easier access permitted in vivo lentivirus-mediated gene transfer which targeted specific cells. This model of engraftment under the skeletal muscle epimysium is a new approach for longitudinal studies, which allows localized manipulation to determine the regulation of human pancreatic development

Développement du pancréas humain embryonnaire ex vivo / in vivo : La greffe musculaire : un nouveau modèle d'étude longitudinale et dynamique

Whilst sporadic human genetic studies have permitted some comparisons between rodent and human pancreatic development, the lack of a robust experimental system has not permitted detailed examination of human pancreatic development. We previously developed a xenograft model of immature human fetal pancreas grafted under the kidney capsule of immune-incompetent mice, which allowed the development of human pancreatic beta cells. Here, we compared the development of human and murine fetal pancreatic grafts either under skeletal muscle epimysium or under the renal capsule. We demonstrated that human pancreatic beta cell development occurs) both by differentiation of pancreatic progenitors and by proliferation of developing beta cells. The superficial location of the skeletal muscle graft and its easier access permitted in vivo lentivirus-mediated gene transfer which targeted specific cells. This model of engraftment under the skeletal muscle epimysium is a new approach for longitudinal studies, which allows localized manipulation to determine the regulation of human pancreatic development.Au-delà de l’intérêt cognitif de la démarche, la compréhension des mécanismes qui régissent le développement pancréatique humain reste la clé pour décrypter les acteurs physiopathologiques des maladies du pancréas et pour développer des approches thérapeutiques innovantes. En outre, alors que la cellule bêta de rongeurs et la cellule bêta humaine partagent un grand nombre de similitudes, certaines données indiquent également des différences marquées entre les espèces. L'absence de systèmes expérimentaux robustes , à partir de matériel humain, n'a pas permis un examen détaillé du développement pancréatique humain jusqu’à présent. Dans le laboratoire, il a été précédemment validé un modèle de xénogreffe de pancréas immature humain sous la capsule rénale de souris immuno-incompétentes SCID. Il a été démontré que celui-ci permettait de récapituler l’ensemble des étapes du développement endocrine humain. Néanmoins le site de greffe limitait les possibilités de modifier ce développement, notamment par infection virale. Dans ce travail, nous avons développé et validé un nouveau site de greffe dans le muscle squelettique, plus simple et plus superficiel. En outre, nous démontrons qu’il est possible de créer un pancréas humain partiellement transgénique in vivo en réalisant du transfert de gènes médié par des lentivirus, après injection directe de la solution virale dans le greffon. Ce modèle de greffe dans le muscle est une nouvelle approche permettant d’envisager des études longitudinales, dans lesquelles il serait possible d’étudier la régulation de certains gènes ou le devenir de certaines lignées marquées par des gènes rapporteurs apportés par le virus à différents stades de développement

Résultats à long terme de la cure de reflux gastro-oesophagien par la technique de Nissen-Rossetti laparoscopique chez l'enfant

Matériel et méthode : de juillet 1992 à mai 2003, 155 enfants ont été opérés d'une intervention anti-reflux laparoscopique (15 Nissen, 140 Nissen-Rossetti). Une surveillance comportant un examen clinique, un TOGD et une pHmétrie à 3 mois, 15 mois, et 5 ans post-opératoires ont été proposés à tous les patients. Le suivi minimum pour l'inclusion était de 15 mois, et 3 groupes ont été distingués : les sujets avec un reflux gastro-œsophagien primaire (61), les enfants neurologiques (82), et les patients avec des anomalies anatomiques oeso-gastriques (12 dont 8 atrésies de l œsophage). Résultats : L'âge médian à l'intervention était de 4 ans [1 mois-20 ans]. Vingt-huit enfants sont décédés, dont 26 pour le groupe des neurologiques avec un seul décès imputable à l'intervention (0,6 %). Seize enfants ont été perdus de vue. Le temps médian de pH inférieur à 4 passait de 9,7% en pré-opératoire à 0%, 2,2%, 1,3% respectivement à 3 mois, 1 an et 5 ans. Sept enfants ont été réopérés pour réfection du montage (4,5 %) dans un délais médian de 10 mois [7j -16 mois], 3 provenant du groupe des anomalies anatomiques (25%), 3 du groupe des neurologiques (3,6%) et 1 du groupe des RGO primaire (1,6%). Conclusion : L'intervention de Nissen par laparoscopie est efficace excepté pour les patients de petit poids ayant une anomalie anatomique oeso-gastrique, nous faisant préférer actuellement la laparotomie à la laparoscopie dans cette indication. 75% des enfants neurologiques revus à 5 ans ont des résultats satisfaisants avec une amélioration de leur qualité de vie. Pour le groupe de RGO primaire, plus de 95% sont considérés comme guéris au bilan à 5 ans.NANTES-BU Médecine pharmacie (441092101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF