The metabolic effects of adding exenatide to basal insulin therapy when targeting remission in early type 2 diabetes in a randomized clinical trial

Effect of Time-Restricted Eating on β-Cell Function in Adults With Type 2 Diabetes

CONTEXT

Time-restricted eating (TRE), which consists of restricting the eating window to typically 4 to 8 hours (while fasting for the remaining hours of the day), has been proposed as a nonpharmacological strategy with cardiometabolic benefits but little is known about its metabolic effect on type 2 diabetes mellitus (T2DM).

OBJECTIVE

We evaluated whether TRE can improve pancreatic β-cell function and metabolic status in overweight individuals with early T2DM.

METHODS

In a randomized, crossover trial, 39 participants (mean 2.9 years of diabetes duration, baseline glycated hemoglobin A1c [HbA1c] 6.6% ± 0.7% and body mass index [BMI] 32.4 ± 5.7) were randomly assigned to either an initial intervention consisting of 6 weeks of TRE (20 h-fasting/4 h-eating) or standard lifestyle. The primary outcome of β-cell function was assessed by the Insulin Secretion-Sensitivity Index-2 (ISSI-2) derived from an oral glucose tolerance test.

RESULTS

As compared to standard lifestyle, TRE induced a 14% increase in ISSI-2 (+14.0 ± 39.2%; P = .03) accompanied by a 14% reduction of hepatic insulin resistance as evaluated by HOMA-IR (-11.6% [-49.3 to 21.9]; P = .03). Fasting glucose did not differ between interventions, but TRE yielded a statistically significant reduction in HbA1c (-0.32 ± 0.48%; P < .001). These metabolic improvements were coupled with a reduction of body weight of 3.86% (-3.86 ± 3.1%; P < .001) and waist circumference of 3.8 cm (-3.8 ± 7.5 cm; P = .003).

CONCLUSION

TRE improved β-cell function and insulin resistance in overweight patients with early diabetes, accompanied by beneficial effects on adiposity.

Chitosan based surface modulation of core-shell nanoparticles for oral delivery of exenatide via balancing mucus penetration and cellular uptake

Oral delivery of peptide and protein drugs (PDs) is hindered by the impermeable intestinal mucosa, which consists of both the mucus layer and the epithelium. Therefore, double-layer (mucus layer and epithelium) overcoming nanocarriers need to be designed to enhance the transporting efficiency of PDs. However, the requirements for surface properties to penetrate these two barriers are quite distinct. In this study, nanoparticles (NPs) with balanced mucus permeation and cellular uptake were developed by modulating surface properties to improve the endocytosis efficiency of exenatide (EXT). The EXT-loaded ovolecithin (Lipoid E 80)/dextran/bovine serum albumin (EDB) NPs, solidified by sodium trimetaphosphate (STMP), were prepared through double emulsification combined with interfacial crosslinking solidification. The EDB NPs were then coated with cationic polyelectrolyte chitosan (CS) shell to form CS-EDB NPs, which exhibited 83.50 ± 0.44 % of encapsulation efficiency (EE), a particle size of approximately 277.0 ± 3.96 nm, and a Zeta potential of -16.2 ± 0.71 mV. Compared to uncoated EDB NPs, CS-EDB NPs showed a 1.1-fold reduction in mucus penetration (Papp), as measured using the Transwell mucus-penetrating model. However, CS-EDB NPs demonstrated a 2.15-fold and 1.77-fold increase in cellular uptake and transepithelial transport efficiency across a Caco-2/E-12 co-culture model, respectively, primarily driven by energy-dependent endocytosis and partially mediated by macropinocytosis. Furthermore, CS-EDB NPs achieved 13.29 % of pharmacological bioavailability and effectively regulated blood glucose, serum lipid levels, and improved islet function upon long-term administration. In conclusion, the core-shell structured CS-EDB NPs successfully protected against the harsh gastrointestinal tract (GIT) environment, providing improved endocytosis efficiency by slightly compromising mucus penetration while significantly enhancing cellular uptake, offering a promising approach for the oral delivery of PDs.

Pancreatic beta-cell mass and function and therapeutic implications of using antidiabetic medications in type 2 diabetes

Nowadays, the focus of diabetes treatment has switched from lowering the glucose level to preserving glycemic homeostasis and slowing the disease progression. The main pathophysiology of both type 1 diabetes and long-standing type 2 diabetes is pancreatic β-cell mass loss and dysfunction. According to recent research, human pancreatic β-cells possess the ability to proliferate in response to elevated insulin demands. It has been demonstrated that in insulin-resistant conditions in humans, such as obesity or pregnancy, the β-cell mass increases. This ability could be helpful in developing novel treatment approaches to restore a functional β-cell mass. Treatment strategies aimed at boosting β-cell function and mass may be a useful tool for managing diabetes mellitus and stopping its progression. This review outlines the processes of β-cell failure and detail the many β-cell abnormalities that manifest in people with diabetes mellitus. We also go over standard techniques for determining the mass and function of β-cells. Lastly, we provide the therapeutic implications of utilizing antidiabetic drugs in controlling the mass and function of pancreatic β-cells.

Contemporary Clinical Perspectives on Targeting Remission of Type 2 Diabetes

It has long been known that some patients with type 2 diabetes (T2DM) can experience sustained metabolic improvement to near-normal levels of glycemia either spontaneously or after medical intervention. Now recognized as remission of diabetes, this intriguing state is currently more feasible than ever before due to profound advances in metabolic surgery, pharmacologic therapy, and regimens of lifestyle modification. This enhanced capacity to induce remission has revealed new pathophysiologic insights, including the presence of a reversible component of the pancreatic beta-cell dysfunction that otherwise drives the chronic progressive nature of T2DM. In doing so, it has changed the therapeutic landscape by offering new potential management objectives and considerations for patients and providers. However, the excitement around these developments must also be tempered by the sobering realities of our current understanding of remission, including the recognition that this condition may not be permanent (resulting in glycemic relapse over time) and that beta-cell function may not be normalized in the setting of remission. These limitations highlight both the many gaps in our current understanding of remission and the caution with which clinical discussions must be handled for clear patient-directed communication of the pros and cons of targeting this outcome in practice. In this mini-review, we consider this rapidly growing literature, including its implications and its limitations, and thereby seek to provide objective balanced perspectives on targeting remission of T2DM in current clinical care.

Future cardiometabolic implications of insulin hypersecretion in response to oral glucose: a prospective cohort study

Background

The cardiometabolic implications of postprandial hyperinsulinemia are unclear with recent studies suggesting both adverse and beneficial associations. We aimed to evaluate the longitudinal cardiometabolic implications of the post-challenge insulin secretory response over 4-years follow-up.

Methods

In this prospective cohort study, conducted in Toronto (Ontario, Canada), women comprising the full range of antepartum glucose tolerance were recruited in pregnancy (at the time of glucose tolerance screening, late in the second trimester) to undergo cardiometabolic testing in the years thereafter. Participants underwent oral glucose tolerance tests (OGTT) at 1-year, 3-years, and 5-years postpartum, enabling serial assessment of cardiovascular risk factors, glucose tolerance, insulin sensitivity or resistance (Matsuda index, HOMA-IR), and beta-cell function-via Insulin Secretion-Sensitivity Index-2 (ISSI-2) and insulinogenic index/HOMA-IR (IGI/HOMA-IR). Baseline post-challenge insulinemia was assessed with the corrected insulin response (CIR) at 1-year. Cardiometabolic factors were compared between baseline CIR tertiles.

Findings

Between Oct 23, 2003 and March 31, 2014, 306 women were enrolled. In this study population, there was progressive worsening of waist circumference (p = 0.016), HDL (p = 0.018), CRP (p = 0.006), and insulin sensitivity (p < 0.001) from the lowest to middle to highest tertile of CIR at 1-year. However, these adverse features were accompanied by progressively better beta-cell function (both p < 0.001), coupled with lower fasting and 2-h glucose on the OGTT (both p < 0.001). On adjusted longitudinal analyses, higher CIR tertile at 1-year was independently associated with (i) higher ISSI-2 and IGI/HOMA-IR and (ii) lower fasting and 2-h glucose at both 3-years and 5-years (all p < 0.001), but was not associated with BMI, waist, lipids, CRP or insulin sensitivity/resistance. The highest CIR tertile at 1-year predicted lower risk of pre-diabetes or diabetes at both 3-years (adjusted OR = 0.19; 95% CI 0.08-0.45) and 5-years (aOR = 0.18; 0.08-0.39), relative to the lowest tertile.

Interpretation

A robust post-challenge insulin secretory response does not indicate adverse cardiometabolic health but, rather, portends favourable metabolic function in the years to come. Future long-term study of the implications of the post-challenge insulinemic response is warranted.

Funding

Canadian Institutes of Health Research.

The Discovery and Development of Glucagon-Like Peptide-1 Receptor Agonists

Diabetes mellitus has become a serious life-threatening disease. As one of the new drugs for the treatment of diabetes, GLP-1 receptor agonists have attracted a lot of attention. Compared with traditional hypoglycemic drugs, GLP-1 receptor agonists have good safety and tolerability. To a certain extent, they overcome the problem of the short half-life of natural GLP-1 in vivo and can exist stably in patients for a long time, achieving good results in the treatment of diabetes, as well as improving the symptoms of some complications. The GLP-1 receptor agonists in the market are all peptide drugs. Compared with peptide drugs, small molecule agonists have the advantages of low cost and oral administration. In this article, we review the recent research progress of GLP-1 receptor agonists.

Determinants of sustained stabilization of beta-cell function following short-term insulin therapy in type 2 diabetes

In early type 2 diabetes, the strategy of "induction" with short-term intensive insulin therapy followed by "maintenance" with metformin can stabilize pancreatic beta-cell function in some patients but not others. We thus sought to elucidate determinants of sustained stabilization of beta-cell function. In this secondary analysis of ClinicalTrials.Gov NCT02192424, adults with ≤5-years diabetes duration were randomized to 3-weeks induction insulin therapy (glargine/lispro) followed by metformin maintenance either with or without intermittent 2-week courses of insulin every 3-months for 2-years. Sustained stabilization (higher beta-cell function at 2-years than at baseline) was achieved in 55 of 99 participants. Independent predictors of sustained stabilization were the change in beta-cell function during induction and changes in hepatic insulin resistance and alanine aminotransferase during maintenance. Thus, initial reversibility of beta-cell dysfunction during induction and subsequent preservation of hepatic insulin sensitivity during maintenance are associated with sustained stabilization of beta-cell function following short-term insulin and metformin.ClinicalTrials.Gov NCT02192424.

Baseline determinants of remission of type 2 diabetes in response to short-term insulin-based therapy: The pivotal role of beta-cell function

AIM

To identify baseline determinants of diabetes remission in response to short-term insulin-based therapy.

METHODS

In this study, adult patients with type 2 diabetes (T2D) of less than 7 years duration were randomized to 8 weeks of treatment with (a) insulin glargine, (b) glargine + thrice-daily lispro, or (c) glargine + twice-daily exenatide, followed by 12 weeks of washout that enabled assessment of remission (defined as HbA1c < 6.5% after ≥ 3 months without glucose-lowering therapy). At baseline, 8 weeks and washout, beta-cell function was assessed with four measures: Insulin Secretion-Sensitivity Index-2 (ISSI-2), insulinogenic index/Homeostatic Model Assessment for Insulin Resistance (HOMA-IR), ΔC-peptide_0-120 /Δglucose_0-120  × Matsuda and Δinsulin secretion rate (ISR)_0-120 /Δgluc_0-120  × Matsuda.

RESULTS

Diabetes remission was achieved in 31 of 90 participants (34.4%). Compared with their peers, those who went on to remission had lower HbA1c (P < .001) and better beta-cell function at baseline (all four measures P ≤ .01). The non-remission and remission groups did not otherwise differ in baseline insulin sensitivity/resistance (Matsuda, HOMA-IR), body mass index, duration of diabetes, pretrial diabetes medications or allocated insulin-based therapy during the trial. On logistic regression analyses, each baseline measure of beta-cell function emerged as a significant predictor of remission (log ISSI-2: adjusted OR 4.41 [95% CI: 1.71-11.34]; log insulinogenic index/HOMA-IR: 2.21 [1.26-3.89]; log ΔC-peptide_0-120 /Δglucose_0-120  × Matsuda: 1.62 [1.00-2.64]; log ΔISR_0-120 /Δgluc_0-120  × Matsuda: 1.87 [1.09-3.23]). Similarly, higher baseline ISSI-2 tertile predicted longer time to glycaemic relapse after cessation of the insulin-based therapy (log-rank P = .029).

CONCLUSION

Beta-cell function is the dominant baseline pathophysiological determinant of the likelihood of achieving remission of diabetes in response to short-term insulin-based therapy.

A Scoping Review of Trials Designed to Achieve Remission of Type 2 Diabetes with Lifestyle Intervention Alone: Implications for Sub-Saharan Africa

According to the International Diabetes Federation, sub-Saharan Africa is experiencing the highest anticipate increase in the prevalence of type 2 diabetes (T2D) in the world and has the highest percent of people living with T2D who are undiagnosed. Therefore, diagnosis and treatment need prioritization. However, pharmacological hypoglycemics are often unavailable and bariatric surgery is not an option. Therefore, the ability to induce T2D remission through lifestyle intervention alone (LSI-alone) needs assessment. This scoping review evaluated trials designed to induce T2D remission by LSI-alone. PubMed, Embase, Cochrane, and CINAHL databases were searched for trials designed to induce T2D remission through LSI-alone. Of the 928 identified, 63 duplicates were removed. With abstract review, 727 irrelevant articles were excluded. After full-text review, 112 inappropriate articles were removed. The remaining 26 articles described 16 trials. These trials were published between 1984 and 2021 and were conducted in 10 countries, none of which were in Africa. Remission rates varied across trials. Predictors of remission were 10% weight loss and higher BMI, lower A1C and shorter T2D duration at enrollment. However, LSI-alone regimens for newly diagnosed and established T2D were very different. In newly diagnosed T2D, LSI-alone were relatively low-cost and focused on exercise and dietary counseling with or without calorie restriction (~1500 kcal/d). Presumably due to differences in cost, LSI-alone trials in newly diagnosed T2D had higher enrollments and longer duration. For established T2D trials, the focus was on arduous phased dietary interventions; phase 1: low-calorie meal replacement (<1000 kcal/day); phase 2: food re-introduction; phase 3: weight maintenance. In short, LSI-alone can induce remission in both newly diagnosed and established T2D. To demonstrate efficacy in Africa, initial trials could focus on newly diagnosed T2D. Insight gained could provide proof of concept and a foundation in Africa on which successful studies of LSI-alone in established T2D could be built.

The vascular function effects of adding exenatide or meal insulin to basal insulin therapy in early type 2 diabetes

OBJECTIVE

Basal insulin glargine has a neutral effect on cardiovascular risk in type 2 diabetes (T2DM). In practice, basal insulin is often paired with a glucagon-like peptide-1 receptor agonist (GLP1-RA) or meal insulin; however, the cardiovascular implications of these combinations have not been fully elucidated. In this context, we sought to evaluate the vascular function effects of adding the GLP1-RA exenatide or meal insulin lispro to basal glargine therapy in early T2DM.

METHODS

In this 20-week trial, adults with T2DM of < 7-years duration were randomized to 8-weeks treatment with (i) insulin glargine (Glar), (ii) glargine + thrice-daily lispro (Glar/Lispro), or (iii) glargine + twice-daily exenatide (Glar/Exenatide), followed by 12-weeks washout. At baseline, 8-weeks, and washout, fasting endothelial function was assessed with reactive hyperemia index (RHI) measurement by peripheral arterial tonometry.

RESULTS

At baseline, there were no differences in blood pressure (BP), heart rate (HR) or RHI between participants randomized to Glar (n = 24), Glar/Lispro (n = 24), and Glar/Exenatide (n = 25). At 8-weeks, Glar/Exenatide decreased systolic BP (mean - 8.1 mmHg [95%CI - 13.9 to - 2.4], p = 0.008) and diastolic BP (mean - 5.1 mmHg [- 9.0 to - 1.3], p = 0.012) compared to baseline, with no significant changes in HR or RHI. Notably, baseline-adjusted RHI (mean ± SE) did not differ between the groups at 8-weeks (Glar 2.07 ± 0.10; Glar/Lispro 2.00 ± 0.10; Glar/Exenatide 1.81 ± 0.10; p = 0.19), nor did baseline-adjusted BP or HR. There were no differences between the groups in baseline-adjusted RHI, BP or HR after 12-weeks washout.

CONCLUSION

Adding either exenatide or lispro to basal insulin therapy does not appear to affect fasting endothelial function in early T2DM.

TRIAL REGISTRATION

ClinicalTrials.Gov NCT02194595.