Pierre-Yves Benhamou

Human bone marrow mesenchymal stem cells can express insulin and key transcription factors of the endocrine pancreas developmental pathway upon genetic and/or microenvironmental manipulation in vitro.

Multipotential stem cells can be selected from the bone marrow by plastic adhesion, expanded, and cultured. They are able to differentiate not only into multiple cell types, including cartilage, bone, adipose and fibrous tissues, and myelosupportive stroma, but also into mesodermal (endothelium), neuroectodermal, or endodermal (hepatocytes) lineages. Our goal was to characterize the multipotential capacities of human mesenchymal stem cells (hMSCs) and to evaluate their ability to differentiate into insulin‐secreting cells in vitro. hMSCs were obtained from healthy donors, selected by plastic adhesion, and phenotyped by fluorescence‐activated cell sorter and reverse transcription–polymerase chain reaction analysis before and after infection with adenoviruses coding for mouse IPF1, HLXB9, and FOXA2 transcription factors involved early in the endocrine developmental pathway. We found that native hMSCs have a pluripotent phenotype (OCT4 expression and high telomere length) and constitutively express NKX6‐1 at a low level but lack all other transcription factors implicated in beta‐cell differentiation. In all hMSCs, we detected mRNA of cytokeratin 18 and 19, epithelial markers present in pancreatic ductal cells, whereas proconvertase 1/3 mRNA expression was detected only in some hMSCs. Ectopic expression of IPF1, HLXB9, and FOXA2 with or without islet coculture or islet‐conditioned medium results in insulin gene expression. In conclusion, our results demonstrated that in vitro human bone marrow stem cells are able to differentiate into insulin‐expressing cells by a mechanism involving several transcription factors of the beta‐cell developmental pathway when cultured in an appropriate microenvironment.

The Diabeo Software Enabling Individualized Insulin Dose Adjustments Combined With Telemedicine Support Improves HbA1c in Poorly Controlled Type 1 Diabetic Patients A 6-month, randomized, open-label, parallel-group, multicenter trial (TeleDiab 1 Study)

OBJECTIVE To demonstrate that Diabeo software enabling individualized insulin dose adjustments combined with telemedicine support significantly improves HbA1c in poorly controlled type 1 diabetic patients. RESEARCH DESIGN AND METHODS In a six-month open-label parallel-group, multicenter study, adult patients (n = 180) with type 1 diabetes (>1 year), on a basal-bolus insulin regimen (>6 months), with HbA1c ≥8%, were randomized to usual quarterly follow-up (G1), home use of a smartphone recommending insulin doses with quarterly visits (G2), or use of the smartphone with short teleconsultations every 2 weeks but no visit until point end (G3). RESULTS Six-month mean HbA1c in G3 (8.41 ± 1.04%) was lower than in G1 (9.10 ± 1.16%; P = 0.0019). G2 displayed intermediate results (8.63 ± 1.07%). The Diabeo system gave a 0.91% (0.60; 1.21) improvement in HbA1c over controls and a 0.67% (0.35; 0.99) reduction when used without teleconsultation. There was no difference in the frequency of hypoglycemic episodes or in medical time spent for hospital or telephone consultations. However, patients in G1 and G2 spent nearly 5 h more than G3 patients attending hospital visits. CONCLUSIONS The Diabeo system gives a substantial improvement to metabolic control in chronic, poorly controlled type 1 diabetic patients without requiring more medical time and at a lower overall cost for the patient than usual care.

Adenovirus-mediated catalase gene transfer reduces oxidant stress in human, porcine and rat pancreatic islets

Summary Susceptibility of pancreatic islets to oxidant stress may affect islet viability and contribute to primary non function of allo- or xenogenic grafts. We investigated the influence of overexpression of catalase (CAT) on the viability of human, porcine and rat islets, as well as INS-1 beta-cell line. Islets were transfected with a replication-deficient adenovirus vector containing human CAT cDNA under the control of the adenovirus major late promoter (AdCAT) or a vector containing no foreign gene (AdNull) and used as a control. Oxidant stress was induced 48 h later by xanthine oxidase-hypoxanthine (XO 25 mU/ml, HX 0.5 mmol/l) or hydrogen peroxide (100 or 250 μmol/l). Islet cell viability was assessed 72 h after CAT transfer by 4-[3-(4-Idophenyl)-2-(4 nitrophenyl)-2H-5-tetrazolio]-1,2,benzene disulphonate (WST-1) test. Baseline catalase activity was three to fourfold lower in porcine than in human islets. CAT activity was reproducibly increased 2.5- to 7-fold in AdCAT infected islets, at least for 13 days. Overall, AdCAT conferred on human and pig islets a protection of 26.1 ± 6.1 and 21.2 ± 9.8 % on XOHX injury and 35.4 ± 4.2 and 57.9 ± 10.5 % on H2O2 stress. Similarly, rat islet cells and INS-1 cells were protected on XOHX stress by 17.8 ± 2.3 and 30.8 ± 8.7 %, respectively. AdNull had no effect. Basal and stimulated insulin secretion was preserved in AdCAT-transfected human islets despite a XOHX challenge. This study validates adenovirus-mediated catalase gene transfer as a realistic approach to reduce non specific inflammation effects on human or porcine islet grafts. Moreover the relevance of defense mechanisms, previously suggested in human islets, is here illustrated in porcine islets. [Diabetologia (1998) 41: 1093–1100]

Human islet transplantation network for the treatment of Type I diabetes: first data from the Swiss-French GRAGIL consortium (1999–2000)

Aims/hypothesis. Improvements in islet transplantation require clinical series large enough to implement controlled new strategies. The goal of this study was to demonstrate the feasibility of a multicentre network for islet transplantation in Type I (insulin-dependent) diabetic patients. Methods. The five centres (Besançon, Geneva, Grenoble, Lyon, Strasbourg) of the GRAGIL network allow pancreas procurement, recipient recruitment, transplantation procedure and follow-up. Islet isolation is, however, performed in one single laboratory (Geneva). Pancreata were procured in each of the five centres and transported to Geneva with an ischaemia time of less than 8 hours. Islets were isolated using a standard automated method. If the islet number was too low for a graft ( < 6000 Islet-equivalent /kg), islets were cultured up to 12 days until another isolation was possible. Islets were transplanted by percutaneous transhepatic intraportal injection. Immunosuppression consisted of cyclosporine, mycophenolate mofetil, steroids and an anti-interleukin 2 receptor antibody. Results. From March 1999 to June 2000, 56 pancreata procurements were performed with an average yield of 234 500 islet-equivalent, with 32 preparations over 200 000 islet-equivalent. Ten C-peptide negative Type I diabetic patients (5 men and 5 women, median age 44 years, median diabetes duration 29 years) with an established kidney graft ( > 6 months) received 9030 ± 1090 islet-equivalent/kg with a median purity of 63 %. The number of pancreata required for each graft was 1 (n = 5) or 2 (n = 5). At the completion of a 12 month follow-up, we observed 0 % primary nonfunction, 50 % graft survival and 20 % insulin-independence. Conclusions/interpretation. This study demonstrates the interest and the feasibility of a multicentre collaboration in human islet transplantation. [Diabetologia (2001) 44: 859–864]

Contribution of adenoviral-mediated superoxide dismutase gene transfer to the reduction in nitric oxide-induced cytotoxicity on human islets and INS-1 insulin-secreting cells

Aims/hypothesis. Vulnerability of pancreatic islets to oxygen free radicals and nitric oxide contributes to islet transplantation obstacles. This susceptibility can be linked to the low expression levels of antioxidant enzymes in islets. Our aim was to investigate the effect of overexpressing Cu/Zn superoxide dismutase in human islets through a simple procedure on the cytotoxic effects of two nitric oxide donors: 3-morpholinosydnonimine (SIN-1) and S-Nitroso-N-acetyl-d,l-penicillamine (SNAP). Methods. Cultured human islets and INS-1 rat-derived insulin-secreting cells were transfected by an E1-deleted adenovirus carrying Cu/Zn SOD cDNA under the control of a cytomegalovirus (CMV) promoter (AdSOD). The viability of the cells was tested by the WST-1 assay (Roche, Indianapolis, Ind., USA). Results. The AdSOD procedure allowed SOD activity to increase by twofold to threefold for 2 to 8 days following transfection. Adenovirus-driven SOD overexpression was associated with a significant reduction of SIN-1-induced cytotoxicity on human islets (69.9 ± 10.5 % protection at 200 μmol/l and 40.5 ± 8.9 % protection at 400 μmol/l) and INS-1 cells (82.2 ± 8.8 % protection at 200 μmol/l and 31.1 ± 5.8 % protection at 400 μmol/l). Protection against increasing doses of SNAP was AdSOD dose-dependent. Transfected islets released significantly more insulin than control islets in glucose-theophyllin-stimulated conditions, without or following exposure to SNAP. Conclusions/interpretation. We thus established that adenoviral-induced overexpression of Cu/Zn SOD can be beneficial to human islet endocrine function and resistance to nitric oxide cytotoxicity. These data could be relevant for the development of new strategies aimed at preventing NO-induced beta-cell damage in an islet transplantation setting. [Diabetologia (2000) 43: 625–631]

Assessment of Patient-Led or Physician-Driven Continuous Glucose Monitoring in Patients With Poorly Controlled Type 1 Diabetes Using Basal-Bolus Insulin Regimens A 1-year multicenter study

OBJECTIVE The benefits of real-time continuous glucose monitoring (CGM) have been demonstrated in patients with type 1 diabetes. Our aim was to compare the effect of two modes of use of CGM, patient led or physician driven, for 1 year in subjects with poorly controlled type 1 diabetes. RESEARCH DESIGN AND METHODS Patients with type 1 diabetes aged 8–60 years with HbA1c ≥8% were randomly assigned to three groups (1:1:1). Outcomes for glucose control were assessed at 1 year for two modes of CGM (group 1: patient led; group 2: physician driven) versus conventional self-monitoring of blood glucose (group 3: control). RESULTS A total of 257 subjects with type 1 diabetes underwent screening. Of these, 197 were randomized, with 178 patients completing the study (age: 36 ± 14 years; HbA1c: 8.9 ± 0.9%). HbA1c improved similarly in both CGM groups and was reduced compared with the control group (group 1 vs. group 3: −0.52%, P = 0.0006; group 2 vs. group 3: −0.47%, P = 0.0008; groups 1 + 2 vs. group 3: −0.50%, P < 0.0001). The incidence of hypoglycemia was similar in the three groups. Patient SF-36 questionnaire physical health score improved in both experimental CGM groups (P = 0.004). Sensor consumption was 34% lower in group 2 than in group 1 (median [Q1–Q3] consumption: group 1: 3.42/month [2.20–3.91] vs. group 2: 2.25/month [1.27–2.99], P = 0.001). CONCLUSIONS Both patient-led and physician-driven CGM provide similar long-term improvement in glucose control in patients with poorly controlled type 1 diabetes, but the physician-driven CGM mode used fewer sensors.

Five-Year Metabolic, Functional, and Safety Results of Patients With Type 1 Diabetes Transplanted With Allogenic Islets Within the Swiss-French GRAGIL Network

OBJECTIVE To describe the 5-year outcomes of islet transplantation within the Swiss-French GRAGIL Network. RESEARCH DESIGN AND METHODS Retrospective analysis of all subjects enrolled in the GRAGIL-1c and GRAGIL-2 islet transplantation trials. Parameters related to metabolic control, graft function, and safety outcomes were studied. RESULTS Forty-four patients received islet transplantation (islet transplantation alone [ITA] 24 patients [54.5%], islet after kidney [IAK] transplantation 20 patients [45.5%]) between September 2003 and April 2010. Recipients received a total islet mass of 9,715.75 ± 3,444.40 IEQ/kg. Thirty-four patients completed a 5-year follow-up, and 10 patients completed a 4-year follow-up. At 1, 4, and 5 years after islet transplantation, respectively, 83%, 67%, and 58% of the ITA recipients and 80%, 70%, and 60% of the IAK transplant recipients reached HbA1c under 7% (53 mmol/mol) and were free of severe hypoglycemia, while none of the ITA recipients and only 10% of the IAK transplant recipients met this composite criterion at the preinfusion stage. Thirty-three of 44 patients (75%) experienced insulin independence during the entire follow-up period, with a median duration of insulin independence of 19.25 months (interquartile range 2–58). Twenty-nine of 44 recipients (66%) exhibited at least one adverse event; 18 of 55 adverse events (33%) were possibly related to immunosuppression; and complications related to the islet infusion (n = 84) occurred in 10 recipients (11.9%). CONCLUSIONS In a large cohort with a 5-year follow-up and in a multicenter network setting, islet transplantation was safe and efficient in restoring good and lasting glycemic control and preventing severe hypoglycemia in patients with type 1 diabetes.

Influence of donor age on islet isolation and transplantation outcome

BACKGROUND It has been suggested that the age of human organ donors might influence islet isolation and transplantation outcome in a negative way due to a decrease of in vivo function in islets isolated from older donors. METHODS We retrospectively analyzed 332 islet isolations according to donor age. We determined isolation outcome by islet yields, transplantation rates, and [beta]-cell function in vitro. Transplanted patients were divided into two groups depending on donor age (n=25 and n=31 patients for <=45- and >45-year-old donors, respectively). We assessed islet graft function by C-peptide/glucose ratio, [beta] score, secretory units of islets in transplantation index, and insulin independence rate at 1, 6, and 12 months after transplantation. RESULTS There was no difference in islet yields between the two groups (251,900+/-14,100 and 244,600+/-8400 islet equivalent for <=45- and >45-year-old donors, respectively). Transplantation rates and stimulation indices were similar in both groups as well. All islet graft function parameters were significantly higher at 1-month follow-up in patients who had received islets from younger donors. At 6-month follow-up after second or third injection and at 12-month follow-up, secretory units of islets in transplantation indices and C-peptide/glucose ratios were significantly higher in patients with donors aged 45 years or younger. CONCLUSIONS These data suggest that, despite similar outcomes of the isolation procedure, islet graft function is significantly influenced by donor age. These results may have important consequences in the definition of pancreas allocation criteria.

Protection of insulin-secreting INS-1 cells against oxidative stress through adenoviral-mediated glutathione peroxidase overexpression.

OBJECTIVES A large fraction of an islet graft can be lost early following allotransplantation from various non specific mechanisms including oxidative stress. Overexpression of antioxidant enzymes could confer a beneficial effect on islets exposed to reactive oxygen and nitrogen species. We examined the viability of beta cells driven to overexpress glutathione peroxidase (GPx) and exposed to a superoxide donor (hypoxanthine/xanthine oxidase HX/XO) and a nitric oxide donor (3-morpholinosydnonimine SIN-1). METHODS Cultured INS-1 rat-derived insulin-secreting cells were transfected by an E1-deleted adenovirus carrying GPx cDNA (AdGPx). Additional experiments were performed with an adenovector carrying Cu/Zn superoxide dismutase cDNA (AdSOD). Cellular viability was tested by the WST-1 colorimetric assay and functionality by static incubation. RESULTS AdGPx increased GPx activity within 48 hours from 0 (untransfected cells) to 60 +/- 11 U/g (cells transfected at an MOI of 25: 1). GPx overexpression significantly reduced cytotoxicity induced by HX/XO from 10.81 +/- 1.41 to 5.42 +/- 2.62% at 10 mU/ml and from 61.19 +/- 4.17 to 52.9 +/- 4.39% at 20 mU/ml (p=0.0002, transfected cells vs control cells). Doses of SIN-1 from 600 to 1000 micromol/l resulted in cytotoxicity ranging from 17.66 +/- 3.48 to 45.97 +/- 6.48% in control cells and from 5.65 +/- 1.37 to 35.80 +/- 5.59% in AdGPx transfected cells (p=0.015). The combination of AdGPx and AdSOD did not exhibit any synergistic cytoprotective effect. Control cells exposed to a HX/XO stress exhibited a reduction in glucose-theophylline stimulated insulin secretion by half, while stressed GPx overexpressing-cells maintained the same insulin secretion level than non-stressed cells. CONCLUSIONS Adenoviral-induced overexpression of GPx enhances the resistance of a rat beta cell line to both reactive oxygen (ROS) and reactive nitrogen species (RNS) cytotoxicity. Transposition of these findings to human islet transplantation with a clinically-relevant procedure deserves further investigations.

High prevalence of obstructive sleep apnoea syndrome in a Type 1 diabetic adult population: a pilot study

Owing tochronichyperglycaemiaandcardiovascularautonomic neuropathy, Type 1 diabetes patients exhibit increased cardiovascular risk [1]. Both glycaemic control and cardiovascular risk are also associated with obstructive sleep apnoea syndrome [2]. Assessing the association systematically and treating both conditions may play a part in improving the prognosis of Type 1 diabetic patients. Forty Type 1 diabetic adults were consecutively recruited during their regular follow-up in a tertiary centre outpatients clinic. Patients were asked to participate in a screening oximetric procedure, in order to detect sleep breathing disorders. Three of the patients had already been investigated for sleep disorders, with two being treated for obstructive sleep apnoea syndrome and one having no sleep disorder. The 37 remaining subjects completed an Epworth sleepiness scale, a questionnaire addressing sleep problems, and spent a night at home with an oximetric recording. Polysomnography was routinely proposed to subjects with borderline or pathological oximetry and proposed at random to 1 ⁄ 10 patients with normal oximetry. Oximetry was classified as normal in the absence of oxygen saturation (SaO2) fluctuations, as pathological when repetitive desaturation–reoxygenation sequences occurred and as borderline when SaO2 fluctuations were limited in amplitude or appeared during limited periods of time. A variability index of SaO2 objectively quantified these SaO2 fluctuations with a previously demonstrated high negative predictive value in detecting obstructive sleep apnoea syndrome [3]. Obstructive sleep apnoea syndrome was defined by an apnoea + hypopnoea index > 15 ⁄ h during polysomnography. Among the 37 oximetric recordings, 13 were normal, nine were borderline and 15 were pathological. Polysomnography was offered to 25 patients, accepted by 18 and sleep apnoea was demonstrated in 14 patients (0 ⁄ 1, 2 ⁄ 4 and 12 ⁄ 13 in