Extracellular hemoglobin combined with an O2 -generating material overcomes O2 limitation in the bioartificial pancreas.

The bioartificial pancreas encapsulating pancreatic islets in immunoprotective hydrogel is a promising therapy for Type 1 diabetes. As pancreatic islets are highly metabolically active and exquisitely sensitive to hypoxia, maintaining O2 supply after transplantation remains a major challenge. In this study, we address the O2 limitation by combining silicone-encapsulated CaO2 (silicone-CaO2 ) to generate O2 with an extracellular hemoglobin O2 -carrier coencapsulated with islets. We showed that the hemoglobin improved by 37% the O2 -diffusivity through an alginate hydrogel and displayed antioxidant properties neutralizing deleterious reactive O2 species produced by silicone-CaO2 . While the hemoglobin alone failed to maintain alginate macroencapsulated neonate pig islets under hypoxia, silicone-CaO2 alone or combined to the hemoglobin restored islet viability and insulin secretion and prevented proinflammatory metabolism (PTGS2 expression). Interestingly, the combination took the advantages of the two individual strategies, improved neonate pig islet viability and insulin secretion in normoxia, and VEGF secretion and PDK1 normalization in hypoxia. Moreover, we confirmed the specific benefits of the combination compared to silicone-CaO2 alone on murine pseudo-islet viability in normoxia and hypoxia. For the first time, our results show the interest of combining an O2 provider with hemoglobin as an effective strategy to overcome O2 limitations in tissue engineering.

hCTLA4-Ig transgene expression in keratocytes modulates rejection of corneal xenografts in a pig to non-human primate anterior lamellar keratoplasty model.

BACKGROUND: Human corneal allografting is an established procedure to cure corneal blindness. However, a shortage of human donor corneas as well as compounding economic, cultural, and organizational reasons in many countries limit its widespread use. Artificial corneas as well as porcine corneal xenografts have been considered as possible alternatives. To date, all preclinical studies using de-cellularized pig corneas have shown encouraging graft survival results; however, relatively few studies have been conducted in pig to non-human primate (NHP) models, and particularly using genetically engineered donors. METHODS: In this study, we assessed the potential benefit of using either hCTLA4-Ig transgenic or α1,3-Galactosyl Transferase (GT) Knock-Out (KO) plus transgenic hCD39/hCD55/hCD59/fucosyl-transferase pig lines in an anterior lamellar keratoplasty pig to NHP model. RESULTS: Corneas from transgenic animals expressing hCTLA4-Ig under the transcriptional control of a neuron-specific enolase promoter showed transgene expression in corneal keratocytes of the stroma and expression was maintained after transplantation. Although a first acute rejection episode occurred in all animals during the second week post-keratoplasty, the median final rejection time was 70 days in the hCTLA4-Ig group vs. 21 days in the wild-type (WT) control group. In contrast, no benefit for corneal xenograft survival from the GTKO/transgenic pig line was found. At rejection, cell infiltration in hCTLA4Ig transgenic grafts was mainly composed of macrophages with fewer CD3+ CD4+ and CD79+ cells than in other types of grafts. Anti-donor xenoantibodies increased dramatically between days 9 and 14 post-surgery in all animals. CONCLUSIONS: Local expression of the hCTLA4-Ig transgene dampens rejection of xenogeneic corneal grafts in this pig-to-NHP lamellar keratoplasty model. The hCTLA4-Ig transgene seems to target T-cell responses without impacting humoral responses, the control of which would presumably require additional peripheral immunosuppression.

Identification of potential organ donors of advanced age in EDs.

OBJECTIVE: In France and in Belgium, as in many countries, there is a shortage of organs for transplantation, which has led to strategies to recruit older potential donors who may die of stroke. METHODS: We conducted a post hoc analysis to identify potential organ donors with cardiac function among a population of dying patients in emergency departments. This population had been selected for a separate multicenter prospective observational study. We identified patients who died of a neurologic cause but had no clinical findings affecting their donor status. RESULTS: Of 2420 patients in the study, 407 died of a neurologic cause; and 233 of these were excluded because of clinical factors that made them ineligible as organ donors. The remaining 174 patients (7.2% of dying patients) could be considered potential organ donors. Their mean age was 75.2 ± 11 years. Sixty-eight (39%) were intubated, and 60 of these (34.5%) were mechanically ventilated. In addition, 94 patients (54%) died within 12 hours (median, 9.3 hours) after admission; and 13 (7%) died while receiving a maximum level of care. No diagnostic procedures were performed to assess brain death. CONCLUSION: A significant number of patients who die in emergency departments could be organ donors, including approximately 7% between 60 and 85 years of age with life-threatening neurologic diseases. However, this percentage may be reduced by family opposition. Emergency physicians should collaborate with intensive care units and local organ donation teams to optimize end-of-life care and maximize the number of potential donors.

Palliative care for patients who died in emergency departments: analysis of a multicentre cross-sectional survey.

OBJECTIVES: A growing number of patients die each year in hospital emergency departments (EDs). Decisions to withhold or to withdraw life-support therapies occur in 80% of patients as described in a multicentre cross-sectional survey including 2420 patients. Palliative care has not been explored in patients dying in this setting. The aim of this study was to assess the incidence of palliative care and to describe this population. METHODS: The authors conducted a post-hoc analysis on a cohort of 2420 patients who died in 174 French and Belgian EDs. The authors identified patients who benefited from palliative care and described this population and the palliative care. RESULTS: Palliative therapies were administered to 1373 patients (56.7%). These therapies included administration of analgesics, sedation, mouth care, repositioning for comfort (as appropriate) and provision of emotional support to the patient and his/her relatives. These palliative measures were provided more frequently in the observation unit of the ED (n=908, 66.2%) than in an examination room (n=465, 33.8%). Median time interval between ED admission and death was longer in patients who received palliative care (n=1373) (median, 15 h; first quartile, 6 h; third quartile, 34 h) than in those who did not (n=1047) (median, 4 h; first quartile, 1 h; third quartile, 10 h) (p<10(-4)). CONCLUSIONS: Palliative care is administered to about half of the patients who die in EDs. This is insufficient as the majority of the patients who died in EDs actually died after a decision to withhold or withdraw life-support therapies. End-of-life management must be improved in EDs.

Optimization of an O2-balanced bioartificial pancreas for type 1 diabetes using statistical design of experiment.

A bioartificial pancreas (BAP) encapsulating high pancreatic islets concentration is a promising alternative for type 1 diabetes therapy. However, the main limitation of this approach is O2 supply, especially until graft neovascularization. Here, we described a methodology to design an optimal O2-balanced BAP using statistical design of experiment (DoE). A full factorial DoE was first performed to screen two O2-technologies on their ability to preserve pseudo-islet viability and function under hypoxia and normoxia. Then, response surface methodology was used to define the optimal O2-carrier and islet seeding concentrations to maximize the number of viable pseudo-islets in the BAP containing an O2-generator under hypoxia. Monitoring of viability, function and maturation of neonatal pig islets for 15 days in vitro demonstrated the efficiency of the optimal O2-balanced BAP. The findings should allow the design of a more realistic BAP for humans with high islets concentration by maintaining the O2 balance in the device.

Assessing the contribution of lower limb mobilization, in the supine position, on shoulder-pelvis girdles dissociation.

BACKGROUND: Several articular, muscular and neurological diseases generate mobility loss in the shoulder and pelvis girdles. Joint mobilization contributes to improving shoulder-pelvis girdles dissociation, but current mobilization techniques are not always successful and standardized. A robotic medical device, DPA Med®, by inducing trunk mobilization through lower limb oscillation has been developed for producing such a shoulder-pelvis girdles dissociation and is already used worldwide in rehabilitation hospitals. RESEARCH QUESTION: To determine the optimal lower limb oscillation frequency that generated the best shoulder-pelvis girdles dissociation using the DPA Med® device. METHODS: Thirty healthy adult volunteers (mean age: 38.6 [SD 15.2] years, mean height: 174 [SD 11.9] cm, mean body mass: 70.3 [SD 14.7] kg) participated in this prospective study. A kinematic analysis quantified pelvic and shoulder girdle mobility (rotation and lateral tilt) at different DPA Med® frequencies, from 0.5 Hz to 1 Hz. A visual analysis of the lower limb movement was also performed, using video sensors, to better understand the kinematics involved. RESULTS: All DPA Med® frequencies have shown significant shoulder-pelvis girdles dissociation (p < 0.05). This study established an optimal oscillation frequency with the minimal interindividual variability at 0.808 Hz. It induced pelvic mobility similar to that of normal gait, in the transverse and frontal planes (10.3°, SD 2.9°, and 12.0°, SD 2.2°, respectively). This trunk mobility was achieved by producing a lemniscate-shaped motion in the lower limbs (an eight-shaped motion in the transverse plane). SIGNIFICANCE: This study has shown that the DPA Med® device is able to induce shoulder-pelvis girdles dissociation similar to that of normal gait and allowed to establish the existence of an optimal DPA Med® oscillation frequency for lower limb mobility at 0.808 Hz. Further studies are required to evaluate its potentially benefits on gait disorders.

Effectiveness of an antenatal maternal supplementation with prebiotics for preventing atopic dermatitis in high-risk children (the PREGRALL study): protocol for a randomised controlled trial.

INTRODUCTION: Atopic dermatitis (AD) is a chronic inflammatory disease affecting 10%-15% of children in Europe. There is a need for new primary preventive therapeutic strategies in at-risk populations. Recent research has indicated that atopic diseases are associated with a disrupted gut microbial 'balance' in early life raising the possibility that interventions which yield optimal patterns of microflora could improve host's health. Prebiotics, sugars with immunomodulatory properties that stimulate the diversity of the digestive microbiota, are ideal candidates for such research. So far, most clinical trials have focused on improving infant gut colonisation postnatally. However, prenatal life is a crucial period during which different tolerance mechanisms are put in place. We aim to determine whether antenatal prebiotics supplementation prevents AD in high-risk children. METHODS AND ANALYSIS: This is a randomised, multicentre, double-blind, trial to evaluate the effectiveness of antenatal prebiotic maternal supplementation (galacto-oligosaccharide/inulin) in pregnant women versus placebo on the occurrence of AD at 1 year of age in at-risk children (defined as having a maternal history of atopic disease). Participating women will be randomised to daily ingestion of a prebiotics or placebo (maltodextrin) from 20 weeks' gestation until delivery. The primary outcome is the prevalence of AD at 1 year of age, using the version of the UK Working Party Diagnostic Criteria optimised for preventive studies. Key secondary endpoints are AD severity, quality of life and prebiotics tolerance. The target sample size is 376 women (188 patients per group) which will provide 80% power to detect a 33% reduction of the risk of AD in the verum group (α=0.05). The primary analysis will be based on the intention-to-treat principle. ETHICS AND DISSEMINATION: Results will be presented in peer-reviewed journals and at international conferences. Ethics approval for the study was obtained from the institutional ethical review board of 'Comité de Protection des Personnes Sud Ouest-Outre-Mer III' of the University Hospital Centre of Bordeaux (2017/13). TRIAL REGISTRATION NUMBER: NCT03183440; Pre-results.

Neu5Gc and α1-3 GAL Xenoantigen Knockout Does Not Affect Glycemia Homeostasis and Insulin Secretion in Pigs.

Xenocell therapy from neonate or adult pig pancreatic islets is one of the most promising alternatives to allograft in type 1 diabetes for addressing organ shortage. In humans, however, natural and elicited antibodies specific for pig xenoantigens, α-(1,3)-galactose (GAL) and N-glycolylneuraminic acid (Neu5Gc), are likely to significantly contribute to xenoislet rejection. We obtained double-knockout (DKO) pigs lacking GAL and Neu5Gc. Because Neu5Gc-/- mice exhibit glycemic dysregulations and pancreatic ß-cell dysfunctions, we evaluated islet function and glucose metabolism regulation in DKO pigs. Isolation of islets from neonate piglets yielded identical islet equivalent quantities to quantities obtained from control wild-type pigs. In contrast to wild-type islets, DKO islets did not induce anti-Neu5Gc antibody when grafted in cytidine monophosphate-N-acetylneuraminic acid hydroxylase KO mice and exhibited in vitro normal insulin secretion stimulated by glucose and theophylline. Adult DKO pancreata showed no histological abnormalities, and immunostaining of insulin and glucagon was similar to that from wild-type pancreata. Blood glucose, insulin, C-peptide, the insulin-to-glucagon ratio, and HOMA-insulin resistance in fasted adult DKO pigs and blood glucose and C-peptide changes after intravenous glucose or insulin administration were similar to wild-type pigs. This first evaluation of glucose homeostasis in DKO pigs for two major xenoantigens paves the way to their use in (pre)clinical studies.

Death in emergency departments: a multicenter cross-sectional survey with analysis of withholding and withdrawing life support.

PURPOSE: To describe the characteristics of patients who die in emergency departments and the decisions to withhold or withdraw life support. METHODS: We undertook a 4-month prospective survey in 174 emergency departments in France and Belgium to describe patients who died and the decisions to limit life-support therapies. RESULTS: Of 2,512 patients enrolled, 92 (3.7%) were excluded prior to analysis because of missing data; 1,196 were men and 1,224 were women (mean age 77.3 +/- 15 years). Of patients, 1,970 (81.4%) had chronic underlying diseases, and 1,114 (46%) had a previous functional limitation. Principal acute presenting disorders were cardiovascular, neurological, and respiratory. Life-support therapy was initiated in 1,781 patients (73.6%). Palliative care was undertaken for 1,373 patients (56.7%). A decision to withhold or withdraw life-sustaining treatments was taken for 1,907 patients (78.8%) and mostly concerned patients over 80 years old, with underlying metastatic cancer or previous functional limitation. Decisions were discussed with family or relatives in 58.4% of cases. The decision was made by a single ED physician in 379 cases (19.9%), and by at least two ED physicians in 1,528 cases (80.1%). CONCLUSIONS: Death occurring in emergency departments mainly concerned elderly patients with multiple chronic diseases and was frequently preceded by a decision to withdraw and/or withhold life-support therapies. Training of future ED physicians must be aimed at improving the level of care of dying patients, with particular emphasis on collegial decision-taking and institution of palliative care.