LONG-TERM METABOLIC AND HORMONAL EFFECTS OF EXENATIDE ON ISLET TRANSPLANT RECIPIENTS WITH ALLOGRAFT DYSFUNCTION: 1318

The initial success of islet transplantation (ITx) is followed by graft dysfunction (GDF) and insulin reintroduction. Exenatide, a GLP-1 agonist, increases insulin and decreases glucagon secretion and has potential for β-cell regeneration. To improve functional islet mass, exenatide treatment was given to ITx recipients with GDF. The objective of this study was to assess metabolic and hormonal effects of exenatide in GDF. In this prospective, single-arm, nonrandomized study, 11 type 1 diabetes recipients of ITx with GDF had HbA1c, weight, insulin requirements, and 5-h mixed meal tolerance test (MMTT; with/without exenatide given before test) at baseline, 3, 6, and 12 months after initiating exenatide treatment. Baseline MMTT showed postprandial hyperglycemia and hyperglucagonemia. Daily exenatide treatment resulted in improved glucose, increased amylin/insulin ratio, and decreased proinsulin/insulin ratio as assessed by MMTT. Glucagon responses remained unchanged. Exenatide administration 1 h before MMTT showed decreased glucagon and glucose at 0 min and attenuation in their postprandial rise. Time-to-peak glucose was delayed, followed by insulin, proinsulin, amylin, and C-peptide, indicating glucose-driven insulin secretion. Five subjects completed 12-month follow-up. Glucose and glucagon suppression responses after MMTT with exenatide were no longer observed. Retrospective 3-month analysis of these subjects revealed higher and sustained glucagon levels that did not suppress as profoundly with exenatide administration, associated with higher glucose levels and increased C-peptide responses. In conclusion, Exenatide suppresses the abnormal postprandial hyperglucagonemia and hyperglycemia observed in GDF. Changes in amylin and proinsulin secretion may reflect more efficient insulin processing. Different degrees of responsiveness to exenatide were identified. These may help guide the clinical management of ITx recipients

What information and the extent of information research participants need in informed consent forms: a multi-country survey

Background: The use of lengthy, detailed, and complex informed consent forms (ICFs) is of paramount concern in biomedical research as it may not truly promote the rights and interests of research participants. The extent of information in ICFs has been the subject of debates for decades; however, no clear guidance is given. Thus, the objective of this study was to determine the perspectives of research participants about the type and extent of information they need when they are invited to participate in biomedical research. Methods: This multi-center, cross-sectional, descriptive survey was conducted at 54 study sites in seven Asia-Pacific countries. A modified Likert-scale questionnaire was used to determine the importance of each element in the ICF among research participants of a biomedical study, with an anchored rating scale from 1 (not important) to 5 (very important). Results: Of the 2484 questionnaires distributed, 2113 (85.1%) were returned. The majority of respondents considered most elements required in the ICF to be \u27moderately important\u27 to \u27very important\u27 for their decision making (mean score, ranging from 3.58 to 4.47). Major foreseeable risk, direct benefit, and common adverse effects of the intervention were considered to be of most concerned elements in the ICF (mean score = 4.47, 4.47, and 4.45, respectively). Conclusions: Research participants would like to be informed of the ICF elements required by ethical guidelines and regulations; however, the importance of each element varied, e.g., risk and benefit associated with research participants were considered to be more important than the general nature or technical details of research. Using a participant-oriented approach by providing more details of the participant-interested elements while avoiding unnecessarily lengthy details of other less important elements would enhance the quality of the ICF

Evaluation of the Intestinal Permeability of Rosmarinic Acid from <i>Thunbergia laurifolia</i> Leaf Water Extract in a Caco-2 Cell Model

Thunbergia laurifolia (TL) has been traditionally used as an antidote and an antipyretic drug by folk healers for centuries in Thailand. Rosmarinic acid (RA) is major compound in TL extract and has attracted great interest due to its potential broad pharmacological effects. Herein, the permeability of RA was investigated in TL extract and as a pure compound in a Caco-2 cell model by using high-performance liquid chromatography with a photodiode array detector (HPLC-PDA). The results reveal that the apparent permeability coefficient (Papp) values of RA in TL extracts and pure RA significantly increased after deconjugation by β-glucuronidase/sulfatase enzymes. Our findings exhibit possible saturable biotransformation of RA and/or membrane transport while penetrated through Caco-2 cells. The cumulative amounts of RA as pure compounds and in TL extracts increased with the exposure time, and the efflux ratio (ER) was 0.27–1.14. RA in the TL extract has a similar absorption in the conjugated form and in the pure compound. The intestinal absorption of them is through passive diffusion. Therefore, our findings conclude that the intestinal transport of RA in TL extracts was mainly penetrated as conjugated forms with glucuronic acid and/or sulfate across Caco-2 cells and transported via passive diffusion

Type 2 Diabetes Mellitus Phenotype and Graft Survival After Islet Transplantation

BACKGROUND: Body fat accumulation decreases insulin sensitivity. It has being associated with earlier onset of type 1 diabetes mellitus (DM) and islet graft failure. The aim of this study was to evaluate whether insulin resistance, characterized by risk factors for type 2 diabetes mellitus (DM), can predict islet graft survival in type 1 DM islet transplant (ITx) recipients. METHODS: Demographic, anthropometrical and laboratory data, as well as family history of type 2 DM (first degree relatives), were collected from 44 ITx recipients. Risk factors for type 2 DM, such as positive family history of type 2 DM (n=11) and overweight (BMI >25 kg/m(2); n=14), were analyzed separately and in combination, which was designated as “type 2 DM phenotype” (n=5). Differences in outcomes (time-to-graft dysfunction and failure) were compared using Kaplan-Meier curves. Cox-regression analysis was performed to control for possible confounding factors. RESULTS: Neither positive family history of type 2 DM nor overweight at baseline could predict islet function outcomes after ITx. However, when both risk factors were grouped, the “type 2 DM phenotype” was associated with earlier islet graft failure (mean estimate graft survival 25.7±9.1 vs. 54.1±5.2 months, P=0.022). These results were sustained after adjustments for confounding variables (OR5.20, 95%CI1.12-24.0). CONCLUSIONS: Predisposition for type 2 DM can coexist with the type 1 DM phenotype and is associated with earlier decline in islet graft function. Prospective clinical trials should address whether it is associated with decreased insulin sensitivity and if insulin sensitizers play a role in prolonging islet graft survival

Improved Long-Term Health-Related Quality of Life After Islet Transplantation

BACKGROUND: Health related quality of life (HRQoL) is one of the most important outcomes to measure effectiveness of an intervention, especially for islet transplantation in which benefits should outweigh risks of long-term immunosuppression. This study aimed to evaluate long-term effects of islet transplantation and to outline possible influential factors. METHODS: Forty islet transplant recipients who completed 344 Health Status Questionnaires (HSQ 2.0) and 384 Diabetes quality of life questionnaires (DQoL) between 2000–2007 were retrospectively reviewed. Assessments were analyzed in pre-transplantation period, then every 3 months after the first infusion for 18 months and every 6 months thereafter. The mean follow-up post-transplantation was 40.8±21.9 (9–72) months. RESULTS: Sustained improvement in DQoL-impact score was observed at all time-points post-transplantation. Similarly, worry and satisfaction scales were significantly better than pre-transplant evaluation for most time-points. Four-out-of-eight HSQ 2.0 scales demonstrated a significant improvement at some time-points. Longitudinal analysis, after adjustments for potential confounding factors, showed significantly sustained improvement in impact scale up to 72 months. Longer diabetes duration, higher insulin dosage and occurrence of adverse events had negative effects on HRQoL. Single islet infusion or islet after kidney transplant recipients showed the lowest values in HSQ 2.0. In contrast, subjects on exenatide therapy had significantly higher HSQ 2.0 scores. CONCLUSIONS: Islet transplantation is associated with long-term improvement in HRQoL. Exenatide usage had a positive effect while single islet infusion, islet after kidney transplantation, longer diabetes duration, higher insulin dosage and adverse events had a negative impact on HRQoL scores

Long-Term Insulin Independence and Improvement in Insulin Secretion After Supplemental Islet Infusion Under Exenatide and Etanercept

BACKGROUND: Progressive graft dysfunction (GDF) and loss of insulin independence (II) has been invariably observed in islet transplant recipients under the ‘Edmonton protocol’. To reestablish II we performed supplemental islet infusions (SI) in recipients of allogeneic islet transplant alone, displaying GDF. To improve the engraftment and long-term graft function of SI, exenatide (EXN) and etanercept treatment at islet infusion, and long-term EXN treatment were tested in a non-randomized pilot clinical trial. METHODS: Patients with GDF received SI under Edmonton-like immunosuppression with daclizumab induction, either without interventions (SI-control; n=5) or with EXN and etanercept treatment (SI-EXN; n=4). Clinical and metabolic profiles were assessed over 18–month follow-up. RESULTS: Long-term II (18 months) was observed in 100% of SI-EXN and in 20% of SI-Control (p=0.04). SI-EXN subjects demonstrated restoration of function better than that seen following initial islet infusions. Comparison of SI-EXN and SI-Control groups demonstrated better responses in SI-EXN subjects at three months post SI. Over the 18 months of follow-up, function was sustained in the SI-EXN subjects better than in SI-Controls. Acute effects of exenatide during MMTT and IVGTT results in improved first and second phase insulin release in response to intravenous glucose (IVGTT), and suppressed postprandial hyperglucagonemia after mixed meal tolerance test (MMTT). CONCLUSION: These results suggest that the combination of exenatide and etanercept improve engraftment and long term islet survival and function in subjects undergoing SI. This data however must be interpreted with some caution due to small sample size, lack of randomization and sequential comparison with historical controls