Preservation Of Β-cell Function Research Articles

Long-Term Outcomes of Total Pancreatectomy and Islet Auto Transplantation for Hereditary/Genetic Pancreatitis

Chronic pancreatitis is a debilitating disease resulting from many causes. The subset with hereditary/genetic pancreatitis (HGP) not only has chronic pain, but also an increased risk for pancreatic cancer. Long-term outcomes of total pancreatectomy (TP) and islet autogeneic transplantation (IAT) for chronic pancreatitis due to HGP are not clear. We reviewed a prospectively maintained database of 484 TP-IATs from 1977 to 2012 at a single center. The outcomes (eg, pain relief, narcotic use, β-cell function, health-related quality of life measures) of patients who received TP-IAT for HGP (protease trypsin 1, n = 38; serine protease inhibitor Kazal type 1, n = 9; cystic fibrosis transmembrane conductance regulator, n = 14; and familial, n = 19) were evaluated and compared with those with non-hereditary/nongenetic causes. All 80 patients with HGP were narcotic dependent and failed endoscopic management or direct pancreatic surgery. Post TP-IAT, 90% of the patients were pancreatitis pain free with sustained pain relief; >65% had partial or full β-cell function. Compared with nonhereditary causes, HGP patients were younger (22 years old vs 38 years old; p ≤ 0.001), had pancreatitis pain of longer duration (11.6 ± 1.1 years vs 9.0 ± 0.4 years; p = 0.016), had a higher pancreas fibrosis score (7 ± 0.2 vs 4.8 ± 0.1; p ≤ 0.001), and trended toward lower islet yield (3,435 ± 361 islet cell equivalent vs 3,850 ± 128 islet cell equivalent; p = 0.28). Using multivariate logistic regression, patients with non-HGP causes (p = 0.019); lower severity of pancreas fibrosis (p < 0.001); shorter duration of years with pancreatitis (p = 0.008); and higher transplant islet cell equivalent per kilogram body weight (p ≤ 0.001) were more likely to achieve insulin independence (p < 0.001). There was a significant improvement in health-related quality of life from baseline by RAND 36-Item Short Form Health Survey and in physical and mental component health-related quality of life scores (p < 0.001). None of the patients in the entire cohort had cancer of pancreatic origin in the liver or elsewhere develop during 2,936 person-years of follow-up. Total pancreatectomy and IAT in patients with chronic pancreatitis due to HGP cause provide long-term pain relief (90%) and preservation of β-cell function. Patients with chronic painful pancreatitis due to HGP with a high lifetime risk of pancreatic cancer should be considered earlier for TP-IAT before pancreatic inflammation results in a higher degree of pancreatic fibrosis and islet cell function loss.

Decompensation of β-cells in diabetes: when pancreatic β-cells are on ICE(R).

Insulin production and secretion are temporally regulated. Keeping insulin secretion at rest after a rise of glucose prevents exhaustion and ultimately failure of β-cells. Among the mechanisms that reduce β-cell activity is the inducible cAMP early repressor (ICER). ICER is an immediate early gene, which is rapidly induced by the cyclic AMP (cAMP) signaling cascade. The seminal function of ICER is to negatively regulate the production and secretion of insulin by repressing the genes expression. This is part of adaptive response required for proper β-cells function in response to environmental factors. Inappropriate induction of ICER accounts for pancreatic β-cells dysfunction and ultimately death elicited by chronic hyperglycemia, fatty acids, and oxidized LDL. This review underlines the importance of balancing the negative regulation achieved by ICER for preserving β-cell function and survival in diabetes.

Effectiveness of Early Intensive Therapy on β-Cell Preservation in Type 1 Diabetes

OBJECTIVETo assess effectiveness of inpatient hybrid closed-loop control (HCLC) followed by outpatient sensor-augmented pump (SAP) therapy initiated within 7 days of diagnosis of type 1 diabetes on the preservation of β-cell function at 1 year.RESEARCH DESIGN AND METHODSSixty-eight individuals (mean age 13.3 ± 5.7 years; 35% female, 92% Caucasian) were randomized to HCLC followed by SAP therapy (intensive group; N = 48) or to the usual-care group treated with multiple daily injections or insulin pump therapy (N = 20). Primary outcome was C-peptide concentrations during mixed-meal tolerance tests at 12 months.RESULTSIntensive-group participants initiated HCLC a median of 6 days after diagnosis for a median duration of 71.3 h, during which median participant mean glucose concentration was 140 mg/dL (interquartile range 134–153 mg/dL). During outpatient SAP, continuous glucose monitor (CGM) use decreased over time, and at 12 months, only 33% of intensive participants averaged sensor use ≥6 days/week. In the usual-care group, insulin pump and CGM use were initiated prior to 12 months by 15 and 5 participants, respectively. Mean HbA1c levels were similar in both groups throughout the study. At 12 months, the geometric mean (95% CI) of C-peptide area under the curve was 0.43 (0.34–0.52) pmol/mL in the intensive group and 0.52 (0.32–0.75) pmol/mL in the usual-care group (P = 0.49). Thirty-seven (79%) intensive and 16 (80%) usual-care participants had a peak C-peptide concentration ≥0.2 pmol/mL (P = 0.30).CONCLUSIONSIn new-onset type 1 diabetes, HCLC followed by SAP therapy did not provide benefit in preserving β-cell function compared with current standards of care.

Acute exposure of beta-cells to troglitazone decreases insulin hypersecretion via activating AMPK

BackgroundIt has been recognized that insulin hypersecretion can lead to the development of insulin resistance and type 2 diabetes mellitus. There is substantial evidence demonstrating that thiazolidinediones are able to delay and prevent the progression of pancreatic β-cell dysfunction. However, the mechanism underlying the protective effect of thiazolidinediones on β-cell function remains elusive. MethodsWe synchronously detected the effects of troglitazone on insulin secretion and AMP-activated protein kinase (AMPK) activity under various conditions in isolated rat islets and MIN6 cells. ResultsLong-term exposure to high glucose stimulated insulin hypersecretion and inhibited AMPK activity in rat islets. Troglitazone-suppressed insulin hypersecretion was closely related to the activation of AMPK. This action was most prominent at the moderate concentration of glucose. Glucose-stimulated insulin secretion was decreased by long-term troglitazone treatment, but significantly increased after the drug withdrawal. Compound C, an AMPK inhibitor, reversed troglitazone-suppressed insulin secretion in MIN6 cells and rat islets. Knockdown of AMPKα2 showed a similar result. In MIN6 cells, troglitazone blocked high glucose-closed ATP-sensitive K+ (KATP) channel and decreased membrane potential, along with increased voltage-dependent potassium channel currents. Troglitazone suppressed intracellular Ca2+ response to high glucose, which was abolished by treatment with compound C. ConclusionOur results suggest that troglitazone provides β-cell “a rest” through activating AMPK and inhibiting insulin hypersecretion, and thus restores its response to glucose. General significanceThese data support that AMPK activation may be an important mechanism for thiazolidinediones preserving β-cell function.

Targeting of memory T cells with alefacept in new-onset type 1 diabetes (T1DAL study): 12 month results of a randomised, double-blind, placebo-controlled phase 2 trial

Type 1 diabetes results from autoimmune targeting of the pancreatic β cells, likely mediated by effector memory T (Tem) cells. CD2, a T cell surface protein highly expressed on Tem cells, is targeted by the fusion protein alefacept, depleting Tem cells and central memory T (Tcm) cells. We postulated that alefacept would arrest autoimmunity and preserve residual β cells in patients newly diagnosed with type 1 diabetes. The T1DAL study is a phase 2, double-blind, placebo-controlled trial in patients with type 1 diabetes, aged 12-35 years who, within 100 days of diagnosis, were enrolled at 14 US sites. Patients were randomly assigned (2:1) to receive alefacept (two 12-week courses of 15 mg intramuscularly per week, separated by a 12-week pause) or a placebo. Randomisation was stratified by site, and was computer-generated with permuted blocks of three patients per block. All participants and site personnel were masked to treatment assignment. The primary endpoint was the change from baseline in mean 2 h C-peptide area under the curve (AUC) at 12 months. Secondary endpoints at 12 months were the change from baseline in the 4 h C-peptide AUC, insulin use, major hypoglycaemic events, and HbA1c concentrations. This trial is registered with ClinicalTrials.gov, number NCT00965458. Of 73 patients assessed for eligibility, 33 were randomly assigned to receive alefacept and 16 to receive placebo. The mean 2 h C-peptide AUC at 12 months increased by 0.015 nmol/L (95% CI -0.080 to 0.110) in the alefacept group and decreased by 0.115 nmol/L (-0.278 to 0.047) in the placebo group, and the difference between groups was not significant (p=0.065). However, key secondary endpoints were met: the mean 4 h C-peptide AUC was significantly higher (mean increase of 0.015 nmol/L [95% CI -0.076 to 0.106] vs decrease of -0.156 nmol/L [-0.305 to -0.006]; p=0.019), and daily insulin use (0.48 units per kg per day for placebo vs 0.36 units per kg per day for alefacept; p=0.02) and the rate of hypoglycaemic events (mean of 10.9 events per person per year for alefacept vs 17.3 events for placebo; p<0.0001) was significantly lower at 12 months in the alefacept group than in the placebo group. Mean HbA1c concentrations at week 52 were not different between treatment groups (p=0.75). So far, no serious adverse events were reported and all patients had at least one adverse event. In the alefacept group, 29 (88%) participants had an adverse event related to study drug versus 15 (94%) participants in the placebo group. In the alefacept group, 14 (42%) participants had grade 3 or 4 adverse events compared with nine (56%) participants in the placebo group; no deaths occurred. Although the primary outcome was not met, at 12 months, alefacept preserved the 4 h C-peptide AUC, lowered insulin use, and reduced hypoglycaemic events, suggesting efficacy. Safety and tolerability were similar in the alefacept and placebo groups. Alefacept could be useful to preserve β-cell function in patients with new-onset type 1 diabetes.

Early Insulinization to Prevent Diabetes Progression

This article reviews data collected from clinical studies regarding the place of early insulin treatment in preservation of β-cell function in type 2 diabetic patients. It emphasizes the stepwise progression of the data, starting with small uncontrolled studies and progressing to larger-scale controlled studies. It summarizes current knowledge in the field, emphasizing the additional information gained from the Outcome Reduction with Initial Glargine Intervention (ORIGIN) trial (1). ### Effect of glucotoxicity and lipotoxicity on β-cells Glucotoxicity and lipotoxicity have long been recognized as having a deleterious effect on both β-cell function and insulin action (2–4). Glucolipotoxicity refers to the combined deleterious effects of elevated glucose and free fatty acids on β-cell mass and function (5). Significant progress has been made in recent years toward a better understanding of the cellular and molecular basis of glucolipotoxicity (5–7). Insulin protects the β-cell by inducing rapid reversal of glucolipotoxicity and β-cell rest (8,9). The rapid reversal of glucolipotoxicity by insulin therapy is one of the justifications for early insulin treatment (2–10). ### Treat to target or treat to failure? The importance of avoiding prolonged hyperglycemia in patients with short diabetes duration in order to minimize its negative effect on late microvascular and macrovascular complications has been established (11). Hence, present guidelines (12–16) recommend early initiation of life style changes with or without metformin and subsequent addition of 2nd- and 3rd-line therapy when previous treatments fail to achieve or maintain the goal. The goals in the treatment of hyperglycemia in newly diagnosed type 2 diabetes are to achieve near-normal glucose control as early as possible in order to preserve β-cell function and maintain long-term normoglycemia. The capacity of antidiabetes medication to maintain prolonged glycemic control (glucose durability) is of great importance. In the ADOPT study, rosiglitazone (17) demonstrated the best “glucose durability” compared with sulfonylurea (SU) and metformin. …

Bmal1 and β-Cell Clock Are Required for Adaptation to Circadian Disruption, and Their Loss of Function Leads to Oxidative Stress-Induced β-Cell Failure in Mice

Circadian disruption has deleterious effects on metabolism. Global deletion of Bmal1, a core clock gene, results in β-cell dysfunction and diabetes. However, it is unknown if this is due to loss of cell-autonomous function of Bmal1 in β cells. To address this, we generated mice with β-cell clock disruption by deleting Bmal1 in β cells (β-Bmal1(-/-)). β-Bmal1(-/-) mice develop diabetes due to loss of glucose-stimulated insulin secretion (GSIS). This loss of GSIS is due to the accumulation of reactive oxygen species (ROS) and consequent mitochondrial uncoupling, as it is fully rescued by scavenging of the ROS or by inhibition of uncoupling protein 2. The expression of the master antioxidant regulatory factor Nrf2 (nuclear factor erythroid 2-related factor 2) and its targets, Sesn2, Prdx3, Gclc, and Gclm, was decreased in β-Bmal1(-/-) islets, which may contribute to the observed increase in ROS accumulation. In addition, by chromatin immunoprecipitation experiments, we show that Nrf2 is a direct transcriptional target of Bmal1. Interestingly, simulation of shift work-induced circadian misalignment in mice recapitulates many of the defects seen in Bmal1-deficient islets. Thus, the cell-autonomous function of Bmal1 is required for normal β-cell function by mitigating oxidative stress and serves to preserve β-cell function in the face of circadian misalignment.

Effects of Metformin, Metformin Plus Rosiglitazone, and Metformin Plus Lifestyle on Insulin Sensitivity and β-Cell Function in TODAY

OBJECTIVEThe Treatment Options for type 2 Diabetes in Adolescents and Youth (TODAY) trial demonstrated that combination therapy with metformin plus rosiglitazone provided superior durability of glycemic control compared with metformin alone, with significantly lower treatment failure rates (38.6 vs. 51.7%), and metformin plus lifestyle was intermediate. Herein we describe the temporal changes in measures of β-cell function and insulin sensitivity over a 4-year period among the three treatments.RESEARCH DESIGN AND METHODSTODAY participants (699) were tested periodically with an oral glucose tolerance test to determine insulin sensitivity (1/fasting insulin [1/IF]), insulinogenic index (△I30/△G30) or C-peptide index (△C30/△G30), and β-cell function relative to insulin sensitivity (oral disposition index [oDI]).RESULTSDuring the first 6 months, metformin plus rosiglitazone exhibited a significantly greater improvement in insulin sensitivity and oDI versus metformin alone and versus metformin plus lifestyle; these improvements were sustained over 48 months of TODAY. Irrespective of treatment, those who failed to maintain glycemic control had significantly lower β-cell function (∼50%), higher fasting glucose concentration, and higher HbA1c at randomization compared with those who did not fail.CONCLUSIONSThe beneficial change in insulin sensitivity and the resultant lower burden on β-cell function achieved in the first 6 months with metformin plus rosiglitazone appear to be responsible for its superior glycemic durability over metformin alone and metformin plus lifestyle. However, initial β-cell reserve and HbA1c at randomization are independent predictors of glycemic durability. Therefore, efforts to preserve β-cell function before significant loss occurs and to reduce HbA1c may be beneficial in the treatment of youth with type 2 diabetes.

Biomarkers for immune intervention trials in type 1 diabetes

After many efforts to improve and standardize assays for detecting immune biomarkers in type 1 diabetes (T1D), methods to identify and monitor such correlates of insulitis are coming of age. The ultimate goal is to use these correlates to predict disease progression before onset and regression following therapeutic intervention, which would allow performing smaller and shorter pilot clinical trials with earlier endpoints than those offered by preserved β-cell function or improved glycemic control. Here, too, progress has been made. With the emerging insight that T1D represents a heterogeneous disease, the next challenge is to define patient subpopulations that qualify for personalized medicine or that should be enrolled for immune intervention, to maximize clinical benefit and decrease collateral damage by ineffective or even adverse immune therapeutics. This review discusses the current state of the art, setting the stage for future efforts to monitor disease heterogeneity, progression and therapeutic intervention in T1D.

Effect of Calcitriol on Bone Turnover and Osteocalcin in Recent-Onset Type 1 Diabetes

BackgroundVitamin D supplementation in childhood improves the achievement of peak bone mass. We investigated the effect of supplementation with calcitriol on bone turnover in recent-onset type 1 diabetes (T1D). Moreover, the association between osteocalcin and parameters of β-cell function and metabolic control was examined.Methodology/Principal FindingsWe conducted a post-hoc analysis of a double-blind, placebo-controlled study of calcitriol supplementation to preserve β-cell function. 27 recent-onset T1D subjects, mean age 22 years, were randomized to 0.25 µg calcitriol per day or placebo (1∶1) and followed up for one year. Changes in bone formation (osteoclacin) and resorption (beta-CrossLaps) markers, and differences between placebo and calcitriol-treated group were evaluated. At baseline, osteocalcin levels were significantly lower in female than in male patients (P<0.01) while no other metabolic parameters as HbA1c and C-peptide differed between gender. No significant correlations were found in relation to HbA1c, insulin requirement and C-peptide. At 1 year follow-up, no significant differences were observed between calcitriol and placebo groups for osteocalcin and β-CrossLaps. In the placebo group osteocalcin levels were unrelated with parameters of metabolic control, such as C-peptide, insulin requirement or HbA1c. Changes of C-peptide, insulin requirement and HbA1c were not related to osteocalcin levels.ConclusionsSupplementation with 0.25 µg calcitriol per day to patients with new-onset T1D does not affect circulating markers of bone turnover. OC levels were unrelated to β-cell function and other metabolic parameters suggesting that OC is ineffective to control pancreatic function in presence of aggressive autoimmune destruction.

Apoptosis rate and transcriptional response of pancreatic islets exposed to the PPAR gamma agonist Pioglitazone

To explore the molecular pathways underlying thiazolidinediones effects on pancreatic islets in conditions mimicking normo- and hyperglycemia, apoptosis rate and transcriptional response to Pioglitazone at both physiological and supraphysiological glucose concentrations were evaluated. Adult rat islets were cultured at physiological (5.6 mM) and supraphysiological (23 mM) glucose concentrations in presence of 10 μM Pioglitazone or vehicle. RNA expression profiling was evaluated with the PancChip 13k cDNA microarray after 24-h, and expression results for some selected genes were validated by qRT-PCR. The effects of Pioglitazone were investigated regarding apoptosis rate after 24-, 48- and 72-h. At 5.6 mM glucose, 101 genes were modulated by Pioglitazone, while 1,235 genes were affected at 23 mM glucose. Gene networks related to lipid metabolism were identified as altered by Pioglitazone at both glucose concentrations. At 23 mM glucose, cell cycle and cell death pathways were significantly regulated as well. At 5.6 mM glucose, Pioglitazone elicited a transient reduction in islets apoptosis rate while at 23 mM, Bcl2 expression was reduced and apoptosis rate was increased by Pioglitazone. Our data demonstrate that the effect of Pioglitazone on gene expression profile and apoptosis rate depends on the glucose concentration. The modulation of genes related to cell death and the increased apoptosis rate observed at supraphysiological glucose concentration raise concerns about Pioglitazone’s direct effects in conditions of hyperglycemia and reinforce the necessity of additional studies designed to evaluate TZDs effects on the preservation of β-cell function in situations where glucotoxicity might be more relevant than lipotoxicity.

Complementary and Alternative Medicine for Diabetes

Complementary and Alternative Medicine for Diabetes

Comment on: Greenbaum et al. Through the Fog: Recent Clinical Trials to Preserve β-Cell Function in Type 1 Diabetes. Diabetes 2012;61:1323–1330

The interesting article by Greenbaum et al. (1) attempts to trace future pathways toward curative treatments of type 1 diabetes by analyzing the lessons from the previously published trials, particularly those performed in recently diagnosed diabetic patients. The authors emphasize the constant finding observed in the trials with some efficacy on preservation of β-cell function (anti-CD3, anti–B cells, and CTLA-4 Ig), i.e., a biphasic evolution of C-peptide secretion. There was an early significant improvement of C-peptide secretion noted at 6 months in comparison with that in control subjects, but thereafter …

Overexpression of peroxisome proliferator‐activated receptor α in pancreatic β‐cells improves glucose tolerance in diet‐induced obese mice

Lipotoxicity is implicated in pancreatic β-cell dysfunction in obesity-induced type 2 diabetes. In vitro, activation of peroxisome proliferator-activated receptor α (PPARα) has been shown to protect pancreatic β-cells from the lipotoxic effects of palmitate, thereby preserving insulin secretion. Utilizing an adeno-associated virus (dsAAV8), overexpression of PPARα was induced specifically in pancreatic β-cells of adult, C57Bl/6 mice fed a high-fat diet for 20 weeks and carbohydrate metabolism and β-cell mass assessed. We show that overexpression of PPARα in pancreatic β-cells in vivo preserves β-cell function in obesity, and this improves glucose tolerance by preserving insulin secretion in comparison to control mice with diet-induced obesity. No changes in β-cell mass were observed in PPARα-overexpressing mice compared with diet-induced obese control animals. This model of β-cell-specific PPARα overexpression provides a useful in vivo model for elucidating the mechanisms underlying β-cell lipotoxicity in obesity-induced type 2 diabetes.

A randomized, double-blind, placebo-controlled trial evaluating sitagliptin action on insulin resistance parameters and β-cell function

Aim:To evaluate the impact on glycemic control, insulin secretion and on insulin resistance of a sitagliptin + metformin combination compared to metformin monotherapy in type 2 diabetic, naïve to treatment, patients.Materials and methods: A total of 178 Caucasian type 2 diabetic patients were randomized to take sitagliptin 100 mg once a day or placebo in addition to previously taken metformin, for 12 months. The authors evaluated at 3, 6, 9, and 12 months: body mass index (BMI), glycemic control, fasting plasma insulin (FPI), HOMA-IR, HOMA-β, fasting plasma proinsulin (FPPr), proinsulin/fasting plasma insulin ratio (Pr/FPI ratio), C-peptide, glucagon, retinol binding protein-4 (RBP-4), visfatin, and chemerin. Before and 12 months after the addition of sitagliptin, patients underwent tests to assess insulin sensitivity and insulin secretion.Results: Sitagliptin + metformin gave a better decrease of glycemic control, HOMA-IR and glucagon levels compared to placebo + metformin; sitagliptin + metformin also better increased HOMA-β and all β-cell measurements recorded after the clamp. Regarding adipocytokines, sitagliptin + metformin better reduced RBP-4, visfatin and chemerin levels, compared to placebo + metformin.Conclusion: When metformin alone is not enough to reach an adequate glycemic control, sitagliptin can be a valid option, because of its effects in reducing insulin resistance and in preserving β-cell function.

Regulation of the CCL2 gene in pancreatic β-cells by IL-1β and glucocorticoids: role of MKP-1.

Release of pro-inflammatory cytokines from both resident and invading leukocytes within the pancreatic islets impacts the development of Type 1 diabetes mellitus. Synthesis and secretion of the chemokine CCL2 from pancreatic β-cells in response to pro-inflammatory signaling pathways influences immune cell recruitment into the pancreatic islets. Therefore, we investigated the positive and negative regulatory components controlling expression of the CCL2 gene using isolated rat islets and INS-1-derived β-cell lines. We discovered that activation of the CCL2 gene by IL-1β required the p65 subunit of NF-κB and was dependent on genomic response elements located in the −3.6 kb region of the proximal gene promoter. CCL2 gene transcription in response to IL-1β was blocked by pharmacological inhibition of the IKKβ and p38 MAPK pathways. The IL-1β-mediated increase in CCL2 secretion was also impaired by p38 MAPK inhibition and by glucocorticoids. Moreover, multiple synthetic glucocorticoids inhibited the IL-1β-stimulated induction of the CCL2 gene. Induction of the MAP Kinase Phosphatase-1 (MKP-1) gene by glucocorticoids or by adenoviral-mediated overexpression decreased p38 MAPK phosphorylation, which diminished CCL2 gene expression, promoter activity, and release of CCL2 protein. We conclude that glucocorticoid-mediated repression of IL-1β-induced CCL2 gene transcription and protein secretion occurs in part through the upregulation of the MKP-1 gene and subsequent deactivation of the p38 MAPK. Furthermore, the anti-inflammatory actions observed with MKP-1 overexpression were obtained without suppressing glucose-stimulated insulin secretion. Thus, MKP-1 is a possible target for anti-inflammatory therapeutic intervention with preservation of β-cell function.

Humoral autoimmunity in type 1 diabetes: prediction, significance, and detection of distinct disease subtypes.

Type 1 diabetes mellitus (T1D) is an autoimmune disease encompassing the T-cell-mediated destruction of pancreatic β cells and the production of autoantibodies against islet proteins. In humoral autoimmunity in T1D, the detection of islet autoantibodies and the examination of their associations with genetic factors and cellular autoimmunity constitute major areas in both basic research and clinical practice. Although insulin is a key autoantigen and may be primus inter pares in importance among T1D autoantigens, an abundant body of research has also revealed other autoantigens associated with the disease process. Solid evidence indicates that autoantibodies against islet targets serve as key markers to enroll newly diagnosed T1D patients and their family members in intervention trials aimed at preventing or halting the disease process. The next challenge is perfecting mechanistic bioassays to be used as end points for disease amelioration following immunomodulatory therapies aimed at blocking immune-mediated β-cell injury and, in turn, preserving β-cell function in type 1 diabetes mellitus.

Administration of CD4+CD25highCD127− Regulatory T Cells Preserves β-Cell Function in Type 1 Diabetes in Children

OBJECTIVEType 1 diabetes is a condition in which pancreatic islets are destroyed by self-reactive T cells. The process is facilitated by deficits in the number and suppressive activity of regulatory T cells (Tregs). Here, we show for the first time that the infusion of autologous Tregs prolongs remission in recently diagnosed type 1 diabetes in children.RESEARCH DESIGN AND METHODSWe have administered Tregs in 10 type 1 diabetic children (aged 8–16 years) within 2 months since diagnosis. In total, 4 patients received 10 × 106 Tregs/kg body wt, and the remaining 6 patients received 20 × 106 Tregs/kg body wt. The preparation consisted of sorted autologous CD3+CD4+CD25highCD127− Tregs expanded under good manufacturing practice conditions.RESULTSNo toxicity of the therapy was noted. A significant increase in the percentage of Tregs in the peripheral blood has been observed since the day of infusion. These patients were followed along with matched type 1 diabetic patients not treated with Tregs. Half a year after type 1 diabetes onset (4–5 months after Tregs infusion), 8 patients treated with Tregs still required <0.5 UI/kg body wt of insulin daily, with 2 patients out of insulin completely, whereas the remission was over in the nontreated group. In addition, plasma C-peptide levels were significantly higher in the treated group as compared with those not treated.CONCLUSIONSThis study shows that the administration of Tregs is safe and tolerable in children with recent-onset type 1 diabetes.

An Update in Incretin-Based Therapy: A Focus on Glucagon-Like Peptide-1 Receptor Agonists

The glucagon-like peptide-1 receptor agonists, exenatide and liraglutide, offer a unique mechanism in the treatment of type 2 diabetes mellitus (T2DM) as part of the incretin system. Their mechanism of action is to increase insulin secretion, decrease glucagon release, reduce food intake, and slow gastric emptying. They target postprandial blood glucose values and have some effect on fasting levels as well. In addition, they promote weight loss and may help to preserve β-cell function, both major problems in T2DM patients. Changes in hemoglobin A1c are similar to those produced by other T2DM agents, including thiazolidinediones, low-dose metformin, and sulfonylureas, and better than those caused by α-reductase inhibitors and dipeptidyl peptidase-4 inhibitors. These agents have been safely studied in combination with metformin, sulfonylureas, meglitinides, thiazolidinediones, and insulin therapy. Overall, data are limited for head-to-head comparisons, but it appears that liraglutide may have better efficacy and tolerability compared with exenatide; however, more studies are needed. They are overall well tolerated, with the main adverse events being similar to those with metformin (gastrointestinal intolerances that are transient and dose dependent). However, patients must be monitored for pancreatitis as a rare but possible side effect. For T2DM patients willing to use an injectable agent, exenatide and liraglutide offer another therapeutic option to control hyperglycemia with the potential for weight loss and may be combined with other agents safely.

Through the Fog: Recent Clinical Trials to Preserve β-Cell Function in Type 1 Diabetes

> Dawn portrays shadows and fleeting openings in the heavy fog. First awake, inquisitive eyes attempt to pierce the grayness, searching out a stepping stone secure enough to settle on next. “There it is, a beam showing a path.” Anxious dreams of the night begin to fade. He prepares to move forward, cautiously choosing the direction. Adjacent, others stir. Where is the path they saw so clearly only a short while before? Now, only nothingness surrounds them. The imperative that first drove them to start the journey appears less urgent. Stuck in place, feet encased in heavy mud, their despair spreads to others. “Surely this direction is wrong. There must be an easier path,” they cry. There is no end to be seen, and we have been traveling many, many years. > > —A parable by Carla J. Greenbaum For almost 50 years, type 1 diabetes has been described as an autoimmune disease characterized by the T-cell–mediated destruction of β-cells, which begins long before clinical diagnosis. Clinical trials accepting this premise and aimed at modulating the immune system before or after onset of clinical disease have failed to prevent or cure type 1 diabetes. Nonetheless, clinical trials have provided useful knowledge. Whereas some studies have demonstrated no effect on disease progression, a small number of therapies have transiently delayed the decline of β-cell function in recently diagnosed patients. In an effort to move toward new therapies for type 1 diabetes, we must continue to seek out the “openings in the heavy fog” of our parable. A review of recently completed clinical trials provides knowledge to guide the rational design of future trials. In that spirit, this Perspectives in Diabetes article focuses on critical lessons learned from: 1 ) clinical trials with negative results, 2 ) pilot studies, and 3 ) clinical trials demonstrating transient effects on …