Role of dipeptidyl peptidase 4 inhibitors in the new era of antidiabetic treatment

DPP-4 inhibition by linagliptin ameliorates age-related mild cognitive impairment by regulating microglia polarization in mice

Extensive preclinical evidence demonstrates a causative link between insulin signaling dysfunction and the pathogenesis of Alzheimer's disease (AD), and diabetic drugs may represent a promising approach to fighting AD. However, it remains to be determined which antidiabetic drugs are more effective in preventing cognitive impairment. Thus, the present study investigated the effect of dipeptidyl peptidase-4 (DPP-4) inhibitor linagliptin on cognitive impairment in middle-aged mice by comparing it with the effect of metformin. We found that DPP-4 activity increased in the hippocampus of middle-aged mice, and DPP-4 was mainly expressed by microglia rather than astrocytes and oligodendrocytes. DPP-4 directly regulated M1/M2 microglia polarization following LPS or IL-4 stimulation, while DPP-4 inhibitor, linagliptin, suppressed M1-polarized activation and induced M2-polarized activation. Both linagliptin and metformin enhanced cognitive ability, increased hippocampal synaptic plasticity and neurogenesis, and decreased age-related oxidative stress and inflammation by regulating microglia polarization in the hippocampus of middle-aged mice. The combination of linagliptin and metformin showed a maximum protective effect compared to the individual drugs alone. Loss of macrophage inflammatory protein-1α (MIP-1α), a DPP-4 substrate, abrogated the cognitive protection and anti-inflammation effects of linagliptin. Therefore, the current investigation exhibits a potential utility for DPP-4 inhibition in attenuating microglia-mediated inflammation and preventing mild cognitive impairment (MCI) in middle-aged mice, and the effect was partly mediated by MIP-1α.

Efficacy and Safety of Omarigliptin, a Novel Once-Weekly Dipeptidyl Peptidase-4 Inhibitor, in Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis

BACKGRUOUND

No recent meta-analysis has holistically analyzed and summarized the efficacy and safety of omarigliptin in type 2 diabetes mellitus (T2DM). We conducted a meta-analysis to address this knowledge gap.

METHODS

Electronic databases were searched to identify randomized controlled trials (RCTs) that included patients with T2DM who received omarigliptin in the intervention arm. The control arm consisted of either a placebo (passive control group [PCG]) or an active comparator (active control group [ACG]). The primary outcome assessed was changes in hemoglobin A1c (HbA1c), while secondary outcomes included variations in glucose levels, achievement of glycemic targets, adverse events (AEs), and hypoglycemic events.

RESULTS

From 332 initially screened articles, data from 16 RCTs involving 8,804 subjects were analyzed. Omarigliptin demonstrated superiority over placebo in reducing HbA1c levels (mean difference, -0.58%; 95% confidence interval, -0.75 to -0.40; P<0.00001; I2=91%). Additionally, omarigliptin outperformed placebo in lowering fasting plasma glucose, 2-hour postprandial glucose, and in the percentage of participants achieving HbA1c levels below 7.0% and 6.5%. The glycemic efficacy of omarigliptin was similar to that of the ACG across all measures. Although the omarigliptin group experienced a higher incidence of hypoglycemic events compared to the PCG, the overall AEs, serious AEs, hypoglycemia, and severe hypoglycemia were comparable between the omarigliptin and control groups (PCG and ACG).

CONCLUSION

Omarigliptin has a favorable glycemic efficacy and safety profile for managing T2DM.

Impact on Knowledge, Competence, and Performance of a Faculty-Led Web-Based Educational Activity for Type 2 Diabetes and Obesity: Questionnaire Study Among Health Care Professionals and Analysis of Anonymized Patient Records

BACKGROUND

Strategies for managing type 2 diabetes (T2D) and obesity are evolving with the introduction of targeted therapies, including incretin-based dual agonists and growing knowledge of the importance of multidisciplinary care. Accessible, effective continuing medical education (CME) activities are required to ensure that health care professionals (HCPs) understand and can implement the most recent data to optimize patient outcomes.

OBJECTIVE

We aimed to measure changes in knowledge, competence, and self-reported performance and quantitatively evaluate changes in performance using anonymized patient data following participation in a web-based educational activity. The faculty-led CME-accredited activity was based on incretin-based dual agonists and patient education on T2D and obesity. The remaining educational gaps in this field were also identified.

METHODS

A CME-accredited, web-based, multidisciplinary (touchMDT) educational activity titled "The future for glycemic control and weight loss in T2D and obesity: Incretin-based dual-agonists and optimizing patient education" was developed. HCP knowledge, competence, and performance were assessed before and after the activity against Moore's expanded outcomes framework (levels 1-5), using self-reported questionnaires and by analyzing anonymized patient record data.

RESULTS

For evaluating knowledge and competence (50 respondents before and 50 learners after the activity), the mean number of correctly answered questions was significantly higher post activity (median 5.0, IQR 4.0-6.0 to 6.0, IQR 5.0-7.0; mean 4.98, SD 1.22 to 5.78, SD 1.13; P<.001). Modest, nonsignificant improvements in self-reported performance (N=50 respondents preactivity; N=50 learners postactivity) from before to after the activity were observed (median 4.0, IQR 3.25-4.0 to 4.0, IQR 4.0-4.0; mean 3.64, SD 0.69 to 3.76, SD 0.48; P=.32). PPatient data analysis indicated that patients were being treated more intensively postactivity: before the activity, the most commonly used treatment regimens were metformin monotherapy (13/50, 26%) and dual therapy with metformin plus injectable glucagon-like peptide-1 (GLP-1) receptor agonist (RA; 11/50, 22%); post activity, this changed to dual therapy with metformin plus injectable GLP-1 RA (12/50, 24%) and triple therapy with metformin plus injectable GLP-1 RA plus sodium-glucose cotransporter-2 inhibitor (SGLT2i; 10/50, 20%). In addition, there was an increased number of referrals to a combination of specialists (physicians referred 27%, 8/30 of patients to ≥2 specialists before the activity and 36%, 10/28 to ≥2 specialists post activity). The remaining educational gaps included understanding the biology and psychology of obesity, efficacy and safety data for incretin-based dual agonists, and the role of the diabetes educator or diabetes care and education specialist in managing T2D and obesity.

CONCLUSIONS

This short, web-based CME activity on the management of T2D and obesity led to improvements in HCP knowledge, competence, and performance. Several remaining unmet needs were identified, which can be used to inform the content of future educational activities in this disease area.

Development of a Novel CD26-Targeted Chimeric Antigen Receptor T-Cell Therapy for CD26-Expressing T-Cell Malignancies

Chimeric-antigen-receptor (CAR) T-cell therapy for CD19-expressing B-cell malignancies is already widely adopted in clinical practice. On the other hand, the development of CAR-T-cell therapy for T-cell malignancies is in its nascent stage. One of the potential targets is CD26, to which we have developed and evaluated the efficacy and safety of the humanized monoclonal antibody YS110. We generated second (CD28) and third (CD28/4-1BB) generation CD26-targeted CAR-T-cells (CD26-2G/3G) using YS110 as the single-chain variable fragment. When co-cultured with CD26-overexpressing target cells, CD26-2G/3G strongly expressed the activation marker CD69 and secreted IFNgamma. In vitro studies targeting the T-cell leukemia cell line HSB2 showed that CD26-2G/3G exhibited significant anti-leukemia effects with the secretion of granzymeB, TNFα, and IL-8, with 3G being superior to 2G. CD26-2G/3G was also highly effective against T-cell lymphoma cells derived from patients. In an in vivo mouse model in which a T-cell lymphoma cell line, KARPAS299, was transplanted subcutaneously, CD26-3G inhibited tumor growth, whereas 2G had no effect. Furthermore, in a systemic dissemination model in which HSB2 was administered intravenously, CD26-3G inhibited tumor growth more potently than 2G, resulting in greater survival benefit. The third-generation CD26-targeted CAR-T-cell therapy may be a promising treatment modality for T-cell malignancies.

Antitumor Effects and Mechanisms of Metabolic Syndrome Medications on Hepatocellular Carcinoma

Liver cancer has a high incidence and mortality rate worldwide, with hepatocellular carcinoma (HCC) being the most common histological type. With the decrease in the number of newly infected patients and the spread of antiviral therapy, hepatitis virus-negative chronic liver diseases including steatohepatitis are increasingly accounting for a large proportion of HCC, and an important clinical characteristic is the high prevalence of metabolic syndrome including hypertension, type 2 diabetes (T2D), dyslipidemia, and obesity. Since patients with steatohepatitis are less likely to undergo surveillance for early detection of HCC, they may be diagnosed at an advanced stage and have worse prognosis. Therefore, treatment strategies for patients with HCC caused by steatohepatitis, especially in advanced stages, become increasingly important. Further, hypertension, T2D, and dyslipidemia may occur as side effects during systemic treatment, and there will be increasing opportunities to prescribe metabolic syndrome medications, not only for originally comorbid diseases, but also for adverse events during HCC treatment. Interestingly, epidemiological studies have shown that patients taking some metabolic syndrome medications are less likely to develop various types of cancers, including HCC. Basic studies have also shown that these drugs have direct antitumor effects on HCC. In particular, angiotensin II receptor blockers (a drug group for treating hypertension), biguanides (a drug group for treating T2D), and statins (a drug group for treating dyslipidemia) have shown to elucidate antitumor effects against HCC. In this review, we focus on the antitumor effects of metabolic syndrome medications on HCC and their mechanisms based on recent literature. New therapeutic agents are also increasingly being reported. Analysis of the antitumor effects of metabolic syndrome medications on HCC and their mechanisms will be doubly beneficial for HCC patients with metabolic syndrome, and the use of these medications may be a potential strategy against HCC.

Changes in prescription patterns and doses of oral antidiabetic drugs in Japanese patients with type 2 diabetes (JDDM70)

We assessed the prescription patterns of oral antidiabetic drugs in Japanese patients with type 2 diabetes between 2002 and 2020 using data from the Computerized Diabetes Care database. Among 172,960 patients treated with oral antidiabetic drugs, both the sulfonylurea prescription rate and dose decreased from 2002 to 2020. Prescriptions of biguanides, dipeptidyl peptidase-4 inhibitors and sodium-glucose cotransporter 2 inhibitors increased; their dose and dose frequency remained relatively stable. Trends in oral antidiabetic drug prescriptions changed over time, reflecting guideline recommendations and existing evidence.

Changing Patterns of Antihyperglycaemic Treatment among Patients with Type 2 Diabetes in Hungary between 2015 and 2020-Nationwide Data from a Register-Based Analysis

Background and objectives: In the last couple of years, pharmacological management of patients with type 2 diabetes mellitus (T2DM) have been markedly renewed. The aim of this study was to analyse the changes in prescribing patterns of antidiabetic drugs for treating patients with T2DM in Hungary between 2015 and 2020. Material and Methods: In this retrospective, nationwide analysis, we used the central database of the National Health Insurance Fund. We present annual numbers and their proportion of T2DM patients with different treatment regimens. Results: In the period of 2015−2020, the number of incident cases decreased from 60,049 to 29,865, while prevalent cases increased from 682,274 to 752,367. Patients with metformin (MET) monotherapy had the highest prevalence (31% in 2020). Prevalence of insulin (INS) monotherapy continuously but slightly decreased from 29% to 27% while that of sulfonylurea (SU) monotherapy markedly decreased from 37% to 20%. Dipeptidyl peptidase (DPP-4) inhibitors remained popular in 2020 as monotherapy (5%), in dual combination with MET (12%) and in triple combination with MET and SU (5%). The prevalence of patients with sodium-glucose co-transporter-2 (SGLT-2) inhibitors increased from 1% to 4% in monotherapy, from <1% to 6% in dual combination with MET, and from <1% to 2% in triple oral combination with MET and SU or DPP-4-inhibitors. The prevalence of patients using glucagon-like peptide-1 receptor agonists (GLP-1-RAs) also increased but remained around 1−2% both in monotherapy and combinations. For initiating antihyperglycaemic treatment, MET monotherapy was the most frequently used regime in 2020 (50%), followed by monotherapy with SUs (16%) or INS (10%). After initial MET monotherapy, the incidence rates of patients with add-on GLP-1-RAs (2%, 3%, and 4%) and those of add-on SGLT-2 inhibitors (4%, 6%, and 8%) slowly increased in the subsequent 24, 48, and 72 months, respectively. Conclusions: In the period of 2015−2020, we documented important changes in trends of antihyperglycaemic therapeutic patterns in patients with T2DM which followed the new scientific recommendations but remained below our expectations regarding timing and magnitude. More efforts are warranted to implement new agents with cardiovascular/renal benefits into therapeutic management in time, in a much larger proportion of T2DM population, and without delay.

Incretins as a Potential Treatment Option for Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) is a metabolic disease affecting an increasing number of pregnant women around the world. It is not only associated with numerous perinatal complications but also has long-term consequences impacting maternal health and fetal development. To prevent them, it is important to keep glucose levels under control. As much as 15-30% of GDM patients will require treatment with insulin, metformin, or glyburide. With that in mind, it is crucial to keep searching for novel and improved pharmacotherapies. Nowadays, there are ongoing studies investigating the use of other groups of drugs that have proven successful in the treatment of T2DM. Glucagon-like peptide-1 (GLP-1) receptor agonist and dipeptidyl peptidase-4 (DPP-4) inhibitor are among the drugs targeting the incretin system and are currently receiving significant attention. The aim of our review is to demonstrate the potential of these medications in treating GDM and preventing its later complications. It seems that both groups may be successful in the GDM management used alone or as an addition to better-known drugs, including metformin and glyburide. However, more clinical trials are needed to confirm their importance in GDM treatment and to demonstrate effective therapeutic strategies.

Mitophagy: A potential therapeutic target for insulin resistance

Glucose and lipid metabolism disorders caused by insulin resistance (IR) can lead to metabolic disorders such as diabetes, obesity, and the metabolic syndrome. Early and targeted intervention of IR is beneficial for the treatment of various metabolic disorders. Although significant progress has been made in the development of IR drug therapies, the state of the condition has not improved significantly. There is a critical need to identify novel therapeutic targets. Mitophagy is a type of selective autophagy quality control system that is activated to clear damaged and dysfunctional mitochondria. Mitophagy is highly regulated by various signaling pathways, such as the AMPK/mTOR pathway which is involved in the initiation of mitophagy, and the PINK1/Parkin, BNIP3/Nix, and FUNDC1 pathways, which are involved in mitophagosome formation. Mitophagy is involved in numerous human diseases such as neurological disorders, cardiovascular diseases, cancer, and aging. However, recently, there has been an increasing interest in the role of mitophagy in metabolic disorders. There is emerging evidence that normal mitophagy can improve IR. Unfortunately, few studies have investigated the relationship between mitophagy and IR. Therefore, we set out to review the role of mitophagy in IR and explore whether mitophagy may be a potential new target for IR therapy. We hope that this effort serves to stimulate further research in this area.

Relook at DPP-4 inhibitors in the era of SGLT-2 inhibitors

SGLT-2 inhibitors (SGLT-2Is) have significantly improved cardio-renal outcomes and are preferred agents in people with cardiovascular diseases, heart failure, and diabetic kidney disease. Similarly, GLP-1 receptor agonists (GLP-1RAs) have significantly improved atherosclerotic cardiovascular outcomes. To this end, DPP-4 inhibitors (DPP-4Is) are cardiac-neutral drugs. While long-acting GLP-1RAs have shown a favorable HbA1c lowering compared to DPP-4Is, there is no clinically meaningful HbA1c lowering difference between SGLT-2Is vs DPP-4Is. Moreover, the glucose-lowering potential of SGLT-2Is gets compromised with a progressive decline in renal functions, unlike DPP-4Is. Furthermore, the HbA1c lowering potential of DPP-4Is is favorable in people with T2DM having a modest baseline HbA1c (8.0%-8.5%) compared with SGLT-2Is which lowers HbA1c larger in a background of higher baseline HbA1c (> 8.5%-9.0%). These findings suggest that the role of DPP-4Is in the management of type 2 diabetes mellitus cannot be completely ignored even in the era of SGLT-2Is.