Impact of moderate exercise on fatty acid oxidation in pancreatic ß-cells and skeletal muscle.

Fatty acids (FA) play a crucial role in glycaemia regulation in healthy and metabolic disorders conditions through various mechanisms. FA oxidation is one of the processes involved in lipid metabolism and can be modulated by exercise. Nowadays, physical activity is known to be an effective strategy for the prevention and treatment of Type 2 Diabetes. Moreover, its intensity, its duration, the sex-gender, the prandial state, exerkines… are as many parameters that can influence glycaemic control. However, the widely debated question is to determine the best type of exercise for patients with metabolic disorders. In this review, we will discuss the impact of exercise intensity, especially moderate activity, on glycaemic control by focussing on FA oxidation in pancreatic ß-cells and skeletal muscle. Finally, thanks to all the recent data, we will determine whether moderate physical activity is a good therapeutic strategy and if FA oxidation represents a target of interest to treat diabetic, obese and insulin-resistant patients.

Relationship between achieved personalized glycaemic targets and monitoring of clinical events in elderly diabetic patients.

AIM: Recent guidelines for the management of type 2 diabetes (T2DM) in the elderly recommend adjusting the therapeutic target (HbA1c) according to the patient's health. Our study aimed to explore the association between achieving the recommended personalized HbA1c target and the occurrence of major clinical events under real-life conditions. METHODS: The T2DM S.AGES cohort was a prospective multicentre study into which 213 general practitioners recruited 983 non-institutionalized T2DM patients aged>65 years. The recommended personalized HbA1c targets were<7%, <8% and <9% for healthy, ill and very ill patients, respectively. Major clinical events (death from any cause, major vascular events and/or hospitalization) were recorded during the 3-year follow-up. Mixed-effects logistic regression models were used for the analyses. RESULTS: Of the 747 patients analyzed at baseline, 551 (76.8%) were at their recommended personalized HbA1c target. During follow-up, 391 patients (52.3%) experienced a major clinical event. Of the patients who did not achieve their personalized HbA1c target (compared with those who did), the risk (OR) of a major clinical event was 0.95 (95% CI: 0.69-1.31; P=0.76). The risk of death, major vascular event and hospitalization were 0.88 (95% CI: 0.40-1.94; P=0.75), 1.14 (95% CI: 0.7-1.83; P=0.59) and 0.84 (95% CI: 0.60-1.18; P=0.32), respectively. CONCLUSION: Over a 3-year follow-up period, our results showed no difference in risk of a major clinical event among patients, regardless of whether or not they achieved their personalized recommended HbA1c target. These results need to be confirmed before implementing a more permissive strategy for treating T2DM in elderly patients.

Impact of the Type of Continuous Insulin Administration on Metabolism in a Diabetic Rat Model.

Exogenous insulin is the only treatment available for type 1 diabetic patients and is mostly administered by subcutaneous (SC) injection in a basal and bolus scheme using insulin pens (injection) or pumps (preimplanted SC catheter). Some divergence exists between these two modes of administration, since pumps provide better glycaemic control compared to injections in humans. The aim of this study was to compare the impacts of two modes of insulin administration (single injections of long-acting insulin or pump delivery of rapid-acting insulin) at the same dosage (4 IU/200 g/day) on rat metabolism and tissues. The rat weight and blood glucose levels were measured periodically after treatment. Immunostaining for signs of oxidative stress and for macrophages was performed on the liver and omental tissues. The continuous insulin delivery by pumps restored normoglycaemia, which induced the reduction of both reactive oxygen species and macrophage infiltration into the liver and omentum. Injections controlled the glucose levels for only a short period of time and therefore tissue stress and inflammation were elevated. In conclusion, the insulin administration mode has a crucial impact on rat metabolic parameters, which has to be taken into account when studies are designed.

Improvement of islet graft function using liraglutide is correlated with its anti-inflammatory properties.

BACKGROUND AND PURPOSE: Liraglutide improves the metabolic control of diabetic animals after islet transplantation. However, the mechanisms underlying this effect remain unknown. The objective of this study was to evaluate the anti-inflammatory and anti-oxidative properties of liraglutide on rat pancreatic islets in vitro and in vivo. EXPERIMENTAL APPROACH: In vitro, rat islets were incubated with 10 µmol·L-1 liraglutide for 12 and 24 h. Islet viability functionality was assessed. The anti-inflammatory properties of liraglutide were evaluated by measuring CCL2, IL-6 and IL-10 secretion and macrophage chemotaxis. The anti-oxidative effect of liraglutide was evaluated by measuring intracellular ROS and the total anti-oxidative capacity. In vivo, 1000 islets were cultured for 24 h with or without liraglutide and then transplanted into the liver of streptozotocin-induced diabetic Lewis rats with or without injections of liraglutide. Effects of liraglutide on metabolic control were evaluated for 1 month. KEY RESULTS: Islet viability and function were preserved and enhanced with liraglutide treatment. Liraglutide decreased CCL2 and IL-6 secretion and macrophage activation after 12 h of culture, while IL-10 secretion was unchanged. However, intracellular levels of ROS were increased with liraglutide treatment at 12 h. This result was correlated with an increase of anti-oxidative capacity. In vivo, liraglutide decreased macrophage infiltration and reduced fasting blood glucose in transplanted rats. CONCLUSIONS AND IMPLICATIONS: The beneficial effects of liraglutide on pancreatic islets appear to be linked to its anti-inflammatory and anti-oxidative properties. These findings indicated that analogues of glucagon-like peptide-1 could be used to improve graft survival.

Clinical use of the co-formulation of insulin degludec and insulin aspart.

AIMS: To provide a review of the available data and practical use of insulin degludec with insulin aspart (IDegAsp). Premixed insulins provide basal and prandial glucose control; however, they have an intermediate-acting prandial insulin component and do not provide as effective basal coverage as true long-acting insulins, owing to the physicochemical incompatibility of their individual components, coupled with the inflexibility of adjustment. The molecular structure of the co-formulation of IDegAsp, a novel insulin preparation, allows these two molecules to coexist without affecting their individual pharmacodynamic profiles. METHODS: Clinical evidence in phase 2/3 trials of IDegAsp efficacy and safety in type 1 and type 2 diabetes mellitus (T1DM and T2DM) have been assessed and summarised. RESULTS: In people with T2DM, once- and twice-daily dosing provides similar overall glycaemic control (HbA1c ) to current modern insulins, but with lower risk of nocturnal hypoglycaemia. In prior insulin users, glycaemic control was achieved with lower or equal insulin doses vs. other basal+meal-time or premix insulin regimens. In insulin-naïve patients with T2DM, IDegAsp can be started once or twice-daily, based on individual need. People switching from more than once-daily basal or premix insulin therapy can be converted unit-to-unit to once-daily IDegAsp, although this strategy should be assessed by the physician on an individual basis. CONCLUSIONS: IDegAsp offers physicians and people with T2DM a simpler insulin regimen than other available basal-bolus or premix-based insulin regimens, with stable daytime basal coverage, a lower rate of hypoglycaemia and some flexibility in injection timing compared with premix insulins.

Impact of Pancreatic Rat Islet Density on Cell Survival during Hypoxia.

In bioartificial pancreases (BP), the number of islets needed to restore normoglycaemia in the diabetic patient is critical. However, the confinement of a high quantity of islets in a limited space may impact islet survival, particularly in regard to the low oxygen partial pressure (PO2) in such environments. The aim of the present study was to evaluate the impact of islet number in a confined space under hypoxia on cell survival. Rat islets were seeded at three different concentrations (150, 300, and 600 Islet Equivalents (IEQ)/cm(2)) and cultured in normal atmospheric pressure (160 mmHg) as well as hypoxic conditions (15 mmHg) for 24 hours. Cell viability, function, hypoxia-induced changes in gene expression, and cytokine secretion were then assessed. Notably, hypoxia appeared to induce a decrease in viability and increasing islet density exacerbated the observed increase in cellular apoptosis as well as the loss of function. These changes were also associated with an increase in inflammatory gene transcription. Taken together, these data indicate that when a high number of islets are confined to a small space under hypoxia, cell viability and function are significantly impacted. Thus, in order to improve islet survival in this environment during transplantation, oxygenation is of critical importance.

Design, characterisation, and bioefficiency of insulin-chitosan nanoparticles after stabilisation by freeze-drying or cross-linking.

Insulin delivery by oral route would be ideal, but has no effect, due to the harsh conditions of the gastrointestinal tract. Protection of insulin using encapsulation in self-assembled particles is a promising approach. However, the lack of stability of this kind of particles in biological environments induces a low bioavailability of encapsulated insulin after oral administration. The objective of this work was to evaluate the effect of two stabilisation strategies alone or combined, freeze-drying and cross-linking, on insulin-loaded chitosan NPs, and to determine their bioefficiency in vitro and in vivo. NPs were prepared by complex coacervation between insulin and chitosan, stabilised either by cross linking with sodium tripolyphosphate solution (TPP), by freeze-drying or both treatments. In vitro bioefficiency NP uptake was evaluated by flow cytometry on epithelial models (Caco-2/RevHT29MTX (mucus secreting cells)). In vivo, NPs were injected via catheter in the peritoneum or duodenum on insulinopenic rats. Freeze-drying increased in size and charge (+15% vs control 412 ± 7 nm; + 36 ± 0.3 mV) in comparison with cross linking which decreased NP size (-25%) without impacting the NP charge. When combined the consecutive treatments reduced NPs size and increased charges as compared to standard level. Freeze drying is necessary to prevent the destruction of NP in intestinal environment in comparison with no freeze dryed one where 60% of NP were destroyed after 2h. Additionally freeze drying combined with cross linking treatments improved bioefficiency of NP with uptake in cell increased when mucus is present. Combination of both treatment showed a protection of insulin in vivo, with a reduction of glycemia when NPs were administrated. This work showed that the combination of freeze drying and cross linking treatment is necessary to stabilize (freeze-drying) and increase bioefficiency (cross-linking) of self assembled NP in the delivery of insulin in vitro and in vivo.

Impact of an autologous oxygenating matrix culture system on rat islet transplantation outcome.

Disruption of the pancreatic islet environment combined with the decrease in oxygen supply that occurs during isolation leads to poor islet survival. The aim of this study was to validate the benefit of using a plasma-based scaffold supplemented with perfluorodecalin to improve islet transplantation outcome. Rat islets were cultured in three conditions: i) control group, ii) plasma based-matrix (P-matrix), and iii) P-matrix supplemented with emulsified perfluorodecalin. After 24 h culture, matrix/cell contacts (Integrinß1, p-FAK/FAK, p-Akt/Akt), survival (caspase 3, TUNEL, FDA/PI), function, and HIF-1α translocation were assessed. Afterwards, P-matrices were dissolved and the islets were intraportally transplanted. Graft function was monitored for 31 days with glycaemia and C-peptide follow up. Inflammation was assessed by histology (macrophage and granulocyte staining) and thrombin/anti-thrombin complex measurement. Islet survival correlated with an increase in integrin, FAK, and Akt activation in P-matrices and function was maintained. Perfluorodecalin supplementation decreased translocation of HIF-1α in the nucleus and post-transplantation islet structure was better preserved in P-matrices, but a quicker activation of IBMIR resulted in early loss of graft function. "Oxygenating" P-matrices provided a real benefit to islet survival and resistance in vivo. However, intraportal transplantation is not suitable for this kind of culture due to IBMIR; thus, alternative sites must be explored.

Therapeutic management in ambulatory elderly patients with atrial fibrillation: the S.AGES cohort.

UNLABELLED: Few epidemiologic studies have specifically focused on very old community dwelling population with atrial fibrillation (AF). The objectives of the AF-S.AGES cohort were to describe real-life therapeutic management of non-institutionalized elderly patients with AF according to age groups, i.e., 65-79 and ≥ 80 and to determine the main factors associated with anticoagulant treatment in both groups. METHODS: Observational study (N=1072) aged ≥ 65 years old, recruited by general practitioners. Characteristics of the sample were first evaluated in the overall sample and according to age (< 80 or ≥ 80 years) and to use of anticoagulant treatment at inclusion. Logistic models were used to analyze the determinants of anticoagulant prescription among age groups. RESULTS: Mean age was 78.0 (SD=6.5) years and 42% were ≥ 80 years. Nineteen percent had paroxysmal AF, 15% persistent, 56% permanent and 10% unknown type, 77% were treated with vitamin K antagonists (VKA), 17% with antiplatelet therapy with no differences between age groups. Rate-control drugs were more frequently used than rhythm-control drugs (55% vs. 37%, p < 0.001). VKA use was associated with permanent AF, younger age and cancer in patients ≥ 80 years old and with permanent AF and preserved functional autonomy in patients < 80 years old. Hemorrhagic scores were independently associated with non-use of VKA whereas thromboembolic scores were not associated with VKA use. CONCLUSIONS: In this elderly AF outpatient population, use of anticoagulant therapy was higher even after 80 years than in previous studies suggesting that recent international guidelines are better implemented in the elderly population.

Substitution of insulin by exenatide in bad controlled type 2 diabetic patients: efficacy and predictive factors.

AIM: Exenatide therapy is indicated in type 2 diabetes after failure of oral antidiabetic agents (OAD). The aim of this observational prospective study was to assess efficacy of exenatide, in improving HbA1c of at least of 1% (responders) in type 2 diabetic patients treated previously with insulin. METHODS: Thirty-six patients (HbA1c >7.5%), with chronic bad glycemic control, were hospitalized to improve glycemia using transient continuous insulin infusion followed by administration of exenatide and OAD agents. In these patients, insulin had been introduced previously because of OAD failure without any sign of severe insulin deficiency. RESULTS: On the 27 patients analyzed at 3 months, 19 patients were responders (HbA1c: M0: 9.9±1.7%; M3: 7.6±1.2%). Among the 8 non-responders, only 4 deteriorated their HbA1c. After 9 months, 10 patients remained Responders (HbA1c: 7±0.9%). Predictive factors for an improvement of glycemic control were: diabetes duration shorter than 12 years, ratio fasting glycemia/C-peptide less than 1, fasting C-peptide higher than 2.0 µg/L and mean capillary blood glucose after 3 days of exenatide lower than 200 mg/dL. These criteria remained valid in case of a high HbA1c at baseline. CONCLUSION: In patients with no signs of insulin dependence and in case of insulin failure, exenatide associated to OAD may be tried in order to improve glycemic control, this objective was reached by 70% of our patients. Predictive factors for good response, easily available in clinical practice, may help therapeutic choices.

Early effects of liver regeneration on endocrine pancreas: in vivo change in islet morphology and in vitro assessment of systemic effects on ß-cell function and viability in the rat model of two-thirds hepatectomy.

Liver and pancreas share key roles in glucose homeostasis. Liver regeneration is associated with systemic modifications and depends especially on pancreatic hormones. The aim of the study was to investigate the role of systemic factors released after two-thirds hepatectomy (2/3H) on early possible consequences of liver regeneration on endocrine pancreas structure and function. The pancreas and serum were harvested 1, 2, or 3 days after 2/3H or sham operation in Lewis rats. The HGF and VEGF serum concentrations and plasma microparticles levels were measured. The fate of endocrine pancreas was examined through islets histomorphometry and function in sham and 2/3H rats. ß-Cell line RIN-m5F viability was assessed after 24 h of growth in media supplemented with 10% serum from 2/3H or sham rats instead of FCS. Three days after surgery, the pancreas was heavier in 2/3H compared to sham rats (0.56 vs. 0.40% of body weight, p < 0.05) and the proportion of islets of intermediate size was lower in 2/3H rats (5 vs. 15%, p < 0.05). Compared to Sham, sera obtained 3 days after hepatectomy were more efficient to maintain the viability of RIN-m5F cells (99 vs. 67%, p < 0.01). Three days after surgery, no significant differences in serum HGF, a trend to significant increase in VEGF concentration and a significant increase in microparticles levels, were observed in 2/3H vs. sham rats (9.8 vs. 6.5 nM Phtd Ser Eq., p < 0.05). Liver regeneration is associated with early effects on islets and could influence ß-cell viability and function by systemic effect.

The therapeutic management of chronic pain in ambulatory care patients aged 65 and over in France: the S.AGES Cohort. Baseline data.

OBJECTIVE: The main objective of the S.AGES (Elderly Subjects) cohort study is to describe the current therapeutic strategy for chronic pain in non-institutionalised elderly patients in France. METHODS: In this prospective cohort study, non-institutionalised patients aged 65 years and over with chronic pain were recruited by general practitioners (GP) across France. All medicinal and non- medicinal prescriptions were recorded at inclusion and will be followed up over 3 years via an eCRF. Data recorded at baseline are presented in this paper. RESULTS: Two hundred and sixty GPs enrolled 1379 evaluable patients between June 3rd, 2009 and June 3rd, 2011. Pain was mainly of a mechanical nature, due to osteoarthritis or common back pain. 80% of the patients had moderate or severe pain. More than a third of patients were treated with a step 1 analgesic (mainly paracetamol), and approximately 30% received a step 2 analgesic (23% dextropropoxyphene and 40.3% tramadol/paracetamol combination). Only 3% received step 3 analgesics; this rate remained low even in patients with severe pain. The proportion of patients treated with an antiepileptic was higher in case of neuropathic pain. More than 25% of patients did not receive any analgesic medication. CONCLUSION: The baseline S.AGES study results exhibit a well-balanced therapeutic management of chronic pain by GPs for ambulatory elderly patients. Clinicaltrials.org NCT01065909.

Efficacy and safety of lixisenatide once daily versus placebo in type 2 diabetes insufficiently controlled on pioglitazone (GetGoal-P).

AIMS: To compare the efficacy and safety of once-daily prandial lixisenatide with placebo in type 2 diabetes mellitus (T2DM) insufficiently controlled by pioglitazone ± metformin. METHODS: This randomized, double-blind study included a 24-week main treatment period and a ≥52-week variable extension period. Patients were randomized 2 : 1 to receive lixisenatide 20 µg once daily or placebo. The primary endpoint was change in glycated haemoglobin (HbA1c) at week 24. RESULTS: In total, 484 patients were randomized: 323 to lixisenatide; 161 to placebo. After 24 weeks, lixisenatide once daily significantly improved HbA1c (-0.56% vs. placebo; p < 0.0001) and increased the proportion of patients achieving HbA1c <7% compared with placebo (52.3% vs. 26.4%, respectively; p < 0.0001) and significantly improved fasting plasma glucose (-0.84 mmol/l vs. placebo; p < 0.0001). There was a small decrease in body weight with lixisenatide once daily and a small increase with placebo, with no statistically significant difference between the two groups. Overall, lixisenatide once daily was well tolerated, with a similar proportion of treatment-emergent adverse events (TEAEs) and serious TEAEs between groups (lixisenatide: 72.4% and 2.5%; placebo: 72.7% and 1.9%). Symptomatic hypoglycaemia rates were also relatively low in both groups (lixisenatide 3.4% and placebo 1.2%), with no severe episodes. Lixisenatide continued to be efficacious and well tolerated during the variable extension period. CONCLUSIONS: Lixisenatide once daily significantly improved glycaemic control with a low risk of hypoglycaemia, and was well tolerated over 24 weeks and during the long-term, double-blind extension period in patients with T2DM insufficiently controlled on pioglitazone ± metformin.

Glycemic management of diabetes by insulin therapy.

Recent technological innovations as insulin analogue formulation, devices for insulin delivery and glucose monitoring have allowed diabetic patients to improve their glycemic control and decrease their level of burden due to diabetes. Intensive insulin therapy via insulin pens, subcutaneous or intraperitoneal insulin infusions using pumps instead of vials and syringes, are associated with improved absorption reproducibility, HbA1c levels, reduced risk of hypo- or hyperglycemia, and increased quality of patient's life. These currently used systems are discussed in this review as well as the future of exogenous insulin therapy: closed loop system, the artificial pancreas, and oral insulin delivery. Glucose homeostasis is directly linked to glycemic regulated by portal insulin administration, thus endogenous insulin therapy might be the most promising treatment to "cure" diabetes. Consequently, pancreas and islet transplantation, and the bioartificial pancreas are described.

Perfluorocarbon emulsions prevent hypoxia of pancreatic ß-cells.

As oxygen carriers, perfluorocarbon emulsions might be useful to decrease hypoxia of pancreatic islets before transplantation. However, their hydrophobicity prevents their homogenisation in culture medium. To increase the surface of contact between islets and Perfluorooctyl bromide (PFOB), and consequently oxygen delivery, we tested effect of a PFOB emulsion in culture medium on ß-cell lines and rat pancreatic islets. RINm5F ß-cell line or pancreatic rat islets were incubated for 3 days in the presence of PFOB emulsion in media (3.5% w/v). Preoxygenation of the medium was performed before culture. Cell viability was assessed by apoptotic markers (Bax and Bcl-2) and by staining (fluoresceine diacetate and propidium iodide). ß-Cell functionality was determined by insulin release during a glucose stimulation test and. Hypoxia markers, HIF-1α and VEGF, were studied at days 1 and 3 using RT-PCR, Western blotting, and ELISA. PFOB emulsions preserved viability and functionality of RINm5F cells with a decrease of HIF-1α and VEGF expression. Islets viability was preserved during 3 days of culture. Secretion of VEGF was higher in untreated control (0.09 ± 0.041 µg VEGF/mg total protein) than in PFOB emulsion incubated islets (0.02 ± 0.19 µg VEGF/mg total protein, n = 4, p < 0.05) at day 1. At day 3, VEGF secretion was increased as compared to day 1 in control (0.23 ± 0.04 µg VEGF/mg total protein) but it was imbalance by the presence of PFOB emulsion (0.09 ± 0.03 µg VEGF/mg total protein, n = 5, p < 0.05). While insulin secretion was maintained in response to a glucose stimulation test until day 3 when islets were incubated in the presence of PFOB emulsion preoxygenated (0.81 ± 0.16 at day 1 vs. 0.75 ± 0.24 at day 3), the ability to secrete insulin in the presence of high glucose concentration was lost in islets controls (0.51 ± 0.18 at day 1 vs. 0.21 ± 0.13 at day 3). Atmospheric oxygen delivery by PFOB emulsion might be sufficient to decrease islets hypoxia. However, to improve islets functionality, overoxygenation is needed. Finally, maintenance of islet viability and functionality for several days after isolation could improve the outcome of islets transplantation.

Instant blood-mediated inflammatory reaction during islet transplantation: the role of Toll-like receptors signaling pathways.

The instant blood-mediated inflammatory reaction (IBMIR) leads to massive destruction of transplanted islets. Islet isolation and time of culture may elicit the release of potent activators of Toll-like receptors (TLRs) signaling pathways during IBMIR. This work sought to evaluate the role of TLR signaling pathways to mediate inflammatory reactions. Isolated rat pancreatic islets were cultured for 12, 24, or 48 hours. Their viability was assessed by fluorescein diacetate/propidium iodide and their functionality, by glucose stimulation tests. Endotoxin levels were quantified using the Limulus Amebocyte Lysate assays. After RNA extraction and reverse transcription, we performed polymerase chain reaction (PCR) arrays. Samples obtained immediately after isolation were defined as controls. Eighty-four genes belonging to the TLR signaling pathways, were compared with control samples. After culture, islets were viable and functional with low endotoxin levels (< 0.1 endotoxin units/mL) showed TLR activation not due to exogenous contamination. Analysis of PCR arrays highlighted significant up-regulation of TLR-2. After 24 hours of culture, TLR-2 was up-regulated to 6.8 ± 0.6-fold (P < .001) compared with controls but decreased to 4.3 ± 1.4-fold after 48 hours. In the same way, expression of myeloid differentiation primary response gene 88 (Myd88) was significantly up-regulated (3.2 ± 0.4-fold [P < .001]) compared with controls. After 12 hours of culture, interleukin-10 gene expression was significantly up-regulated at 11.6 ± 3.7- fold (P < .05), reaching 17.5 ± 8.3 after 24 hours. Finally, the cyclo-oxygenase-2 gene expression was up-regulated to 509 ± 67.1-fold (P < .05) after 12 hours of culture. These data confirmed the implication of TLR signaling pathways in early inflammatory events.

Role of islet culture on angiogenic and inflammatory mechanisms.

Early events hampering islet engraftment may relate to instant blood-mediated inflammatory reaction (IBMIR) and to insufficient islet revascularization inducing ß-cell death. We evaluated the influence of time of culture on angiogenic and inflammatory cellular mechanisms in islet loss in vitro. Rat pancreatic islets cultured for 0, 12, 24, and 48 hours were assessed for functionality using glucose stimulation tests and identification of signaling pathways using polymerase chain reaction (PCR) arrays. Islet functionality decreased significantly immediately. Index of stimulation (IS) was decreased to 2.29 ± 1.05 after 48 hours of culture versus 18.47 ± 4.84 at 0 hours (P < .001). Gene expression studies at 12 hours of culture showed significant overexpression of proinflammatory cytokines and chemokines--interleukin (IL)-6 884.22 ± 282.58 (P < .001) and Cxcl-1 448.09 ± 196.05-fold change (P < .01). Moreover, islets exhibited significant under-expression after 48 hours of genes encoding angiogenic growth factors, such as epidermal growth factor, vascular endothelial growth factor, platelet endothelial cell adhesion molecule 1, a major protein involved in angiogenesis: 0.07 ± 0.02, 0.11 ± 0.08 (P < .001), and 0.17 ± 0.15-fold change (P < .01) respectively. Moreover, tissue inhibitor of metalloproteinases 1, an inhibitor of metallopeptidase, was significantly more over-expressed, namely 54.58 ± 18.08 at 12 hours of culture versus 0.93 ± 0.15/fold change at 0 hours. This study revealed current culture conditions to be deleterious for islet engraftment, possibly due to expression of angiogenic genes and proinflamatory genes during culture.

Improvement of rat islet viability during transplantation: validation of pharmacological approach to induce VEGF overexpression.

Delayed and insufficient revascularization during islet transplantation deprives islets of oxygen and nutrients, resulting in graft failure. Vascular endothelial growth factor (VEGF) could play a critical role in islet revascularization. We aimed to develop pharmacological strategies for VEGF overexpression in pancreatic islets using the iron chelator deferoxamine (DFO), thus avoiding obstacles or safety risks associated with gene therapy. Rat pancreatic islets were infected in vivo using an adenovirus (ADE) encoding human VEGF gene (4.10(8) pfu/pancreas) or were incubated in the presence of DFO (10 µmol/L). In vitro viability, functionality, and the secretion of VEGF were evaluated in islets 1 and 3 days after treatment. Infected islets or islets incubated with DFO were transplanted into the liver of syngenic diabetic rats and the graft efficiency was estimated in vivo by measuring body weight, glycemia, C-peptide secretion, and animal survival over a period of 2 months. DFO induced transient VEGF overexpression over 3 days, whereas infection with ADE resulted in prolonged VEGF overexpression lasting 14 days; however, this was toxic and decreased islet viability and functionality. The in vivo study showed a decrease in rat deaths after the transplantation of islets treated with DFO or ADE compared with the sham and control group. ADE treatment improved body weight and C-peptide levels. Gene therapy and DFO improved metabolic control in diabetic rats after transplantation, but this effect was limited in the presence of DFO. The pharmacological approach is an interesting strategy for improving graft efficiency during transplantation, but this approach needs to be improved with drugs that are more specific.

How technology has changed diabetes management and what it has failed to achieve.

Tremendous improvements have modified diabetes management from pure clinical diagnosis and the discovery of insulin to continuous subcutaneous insulin infusion (CSII) coupled with continuous glucose monitoring (CGM) to allow patients to adapt insulin delivery to glycaemia on a virtually "real-time" basis. Insulin was first discovered in 1923 and, in less than a century, it has been purified, humanized and now synthesized by genetically modified microorganisms. Insulin analogue, kinetics and reproducibility now allow near-normal glycaemia to be targeted without increasing hypoglycaemia, thus allowing greater flexibility in the patient's day-to-day life. In addition, advances have been made over the past few decades in the development of the necessary and complementary technologies for insulin infusion, glucose measurement, glucose insulin interaction and telemedicine. The major remaining limitations are the lack of glycaemic regulation on insulin administration and the burden of parenteral delivery. Thus, the dream of both patients and diabetologists is to close the loop and to build an artificial pancreas.