The Effect of Sodium Glucose Cotransporter-2 Inhibitors on Hemoglobin A1c Variability and Acute Kidney Injury: A Causal Mediation Analysis.

PURPOSE: The role of lower hemoglobin A1c (HbA1c) variability in the effect of sodium glucose cotransporter-2 inhibitors (SGLT2i) on acute kidney injury (AKI) remains unclear. We compared AKI risk between SGLT2i and dipeptidyl peptidase 4 inhibitors (DPP4i) initiators. Additionally, we aimed to explore the extent to which SGLT2i's influence on AKI risk is mediated by reducing long-term HbA1c variability. METHODS: Using 2018-2022 year data in Yinzhou Regional Health Care Database, we included adult, type 2 diabetes patients who were new users of SGLT2i or DPP4i. The effect of SGLT2i versus DPP4i on AKI, HbA1c variability, and AKI through HbA1c variability was compared using inverse probability of treatment weighted Cox proportional hazards models, median regression models, and causal mediation analysis. RESULTS: With a median follow-up of 1.76 years, 19 717 adults (for SGLT2i, n = 6008; for DPP4i, n = 13 709) with type 2 diabetes were included. The adjusted hazard ratio for SGLT2i versus DPP4i was 0.79 (95% confidence interval [CI] 0.64-0.98) for AKI. The adjusted differences in median HbA1c variability score (HVS) and HbA1c reduction were -16.67% (95% CI: -27.71% to -5.62%) and -1.98% (95% CI: -14.34% to 10.38%), respectively. Furthermore, lower AKI risk associated with SGLT2i was moderately mediated (22.77%) through HVS. The results remained consistent across various subgroups and sensitivity analyses. CONCLUSIONS: Compared to DPP4i, lower AKI risk associated with SGLT2i is moderately mediated through HbA1c variability. These findings enhance our understanding of the effect of SGLT2i on AKI and underscore the importance of considering HbA1c variability in diabetes treatment and management.

Pharmacokinetic/Pharmacodynamic modelling of Saxagliptin and its active metabolite, 5-hydroxy Saxagliptin in rats with Type 2 Diabetes Mellitus.

BACKGROUND AND PURPOSES: It is unclear whether the parent Saxagliptin (SAX) in vivo is the same as that in vitro, which is twice that of 5-hydroxy Saxagliptin (5-OH SAX). This study is to construct a Pharmacokinetic-Pharmacodynamic (PK-PD) link model to evaluate the genuine relationship between the concentration of parent SAX in vivo and the effect. METHODS: First, we established a reliable Ultra Performance Liquid Chromatography-Mass Spectrometry (UPLC-MS/MS) method and DPP-4 inhibition ratio determination method. Then, the T2DM rats were randomly divided into four groups, intravenous injection of 5-OH SAX (0.5 mg/kg) and saline group, intragastric administration of SAX (10 mg/kg) and Sodium carboxymethyl cellulose (CMC-Na) group. Plasma samples were collected at different time points for subsequent testing. Finally, we used the measured concentrations and inhibition ratios to construct a PK-PD link model for 5-OH SAX and parent SAX. RESULTS: A two-compartment with additive model showed the pharmacokinetic process of SAX and 5-OH SAX, the concentration-effect relationship was represented by a sigmoidal Emax model and sigmoidal Emax with E0 model for SAX and 5-OH SAX, respectively. Fitting parameters showed SAX was rapidly absorbed after administration (Tmax=0.11 h, t1/2, ka=0.07 h), widely distributed in the body (V ≈ 20 L/kg), plasma exposure reached 3282.06 ng*h/mL, and the elimination half-life was 6.13 h. The maximum plasma dipeptidyl peptidase IV (DPP-4) inhibition ratio of parent SAX was 71.47%. According to the final fitting parameter EC50, EC50, 5-OH SAX=0.46EC50, SAX(parent), it was believed that the inhibitory effect of 5-OH SAX was about half of the parent SAX, which is consistent with the literature. CONCLUSIONS: The PK-PD link model of the parent SAX established in this study can predict its pharmacokinetic process in T2DM rats and the strength of the inhibitory effect of DPP-4 based on non-clinical data.

Comparison of renal prognosis between dipeptidyl peptidase-4 inhibitor users and non-users.

AIM: To evaluate the renal prognosis of dipeptidyl peptidase-4 inhibitor (DPP-4i) users and non-users using real-world Asian data. METHODS: Using databases from DeSC Healthcare, Inc., patients aged 30 years or older who used antidiabetic drugs from 2014 to 2021 were identified. Propensity score matching analyses were used to compare renal prognosis between DPP-4i users and non-users. The primary outcomes were estimated glomerular filtration rate (eGFR) decline and end-stage kidney disease (ESKD) development in the eGFR of 45 mL/min/1.73m2 or higher and eGFR of less than 45 mL/min/1.73m2 groups, respectively. RESULTS: In total, 65 375 and 9866 patients were identified in the eGFR of 45 mL/min/1.73m2 or higher and eGFR of less than 45 mL/min/1.73m2 groups, respectively. In the eGFR of 45 mL/min/1.73m2 or higher group, propensity score matching created 16 002 pairs. A significant difference was observed in the primary outcome of eGFR decline between DPP-4i users and non-users at 2 years (-2.31 vs. -2.56 mL/min/1.73m2: difference, 0.25 mL/min/1.73m2; 95% confidence interval [CI], 0.06-0.44) and 3 years (-2.75 vs. -3.41 mL/min/1.73m2: difference, 0.66 mL/min/1.73m2; 95% CI, 0.39-0.93). In the eGFR less than 45 mL/min/1.73m2 group, propensity score matching created 2086 pairs. After a mean of 2.2 years of observation, ESKD development was 1.15% and 2.30% in users and non-users, respectively, and Kaplan-Meier analysis revealed a significant difference (log rank P = .005). CONCLUSIONS: This retrospective real-world study revealed that patients using DPP-4is had a better renal prognosis than those not using DPP-4is.

Fabrication of novel vildagliptin loaded ZnO nanoparticles for anti diabetic activity.

Diabetes mellitus (DM) is a rapidly prevailing disease throughout the world that poses boundless risk factors linked to several health problems. Vildagliptin is the standard dipeptidyl peptidase-4 (DPP-4) inhibitor type of medication that is used for the treatment of diabetes anti-hyperglycemic agent (anti-diabetic drug). The current study aimed to synthesize vildagliptin-loaded ZnO NPs for enhanced efficacy in terms of increased retention time minimizing side effects and increased hypoglycemic effects. Herein, Zinc Oxide (ZnO) nanoparticles (NPs) were constructed by precipitation method then the drug vildagliptin was loaded and drug loading efficiency was estimated by the HPLC method. X-ray diffraction analysis (XRD), UV-vis spectroscopy, FT-IR, scanning electron microscope (SEM), and EDX analysis were performed for the characterization of synthesized vildagliptin-loaded ZnO NPs. The UV-visible spectrum shows a distinct peak at 363 nm which confirms the creation of ZnO NPs and SEM showed mono-dispersed sphere-shaped NPs. EDX analysis shows the presence of desired elements along with the elemental composition. The physio-sorption studies, which used adsorption isotherms to assess adsorption capabilities, found that the Freundlich isotherm model explains the data very well and fits best. The maximum adsorption efficiency of 58.83% was obtained. Further, In vitro, anti-diabetic activity was evaluated by determining the α-amylase and DPP IV inhibition activity of the product formed. The formulation gave maximum inhibition of 82.06% and 94.73% of α-amylase and DPP IV respectively. While at 1000 µg/ml concentration with IC50 values of 24.11 µg/per ml and 42.94 µg/ml. The inhibition of α-amylase can be ascribed to the interactive effect of ZnO NPs and vildagliptin.

Nobiletin regulates the proliferation and migration of ovarian cancer A2780 cells via DPP4 and TXNIP.

Nobiletin is an active compound extracted from citrus fruits. Research has indicated that nobiletin has a potential inhibitory effect on ovarian cancer (OV). However, the mechanism of action remains unclear. The OV A2780 cells were treated using nobiletin, cell viability was examined using a cell counting kit-8 experiment, and cell migration was examined with a wound healing experiment. Nobiletin targets were retrieved from target databases. Differentially expressed genes (DEG) and weighted gene co-expression network analysis (WGCNA) were conducted on GSE26712 (OV). The intersection of the critical genes for nobiletin's action on OV and gene enrichment and immune infiltration analyses were performed. The Cancer Genome Atlas-OV data and molecular docking helped validate the findings. After adding nobiletin, cell viability and migration significantly decreased (P < 0.01). A total of 88 nobiletin targets and 1288 DEG were identified. The intersection genes were enriched inflammatory response and response to hypoxia. The most related module obtained from WGCNA contained 414 genes (correlation coefficient = 0.77, P < 0.01). DPP4 and TXNIP were recognized as the hub genes. The abundance of macrophages M2 and mast cells activated significantly enhanced with increased DPP4 expression (P < 0.05). The binding energy between DPP4/TXNIP and nobiletin was - 7.012/ - 7.184 kcal/mol, forming 5/2 hydrogen bonds. Nobiletin effectively suppresses the viability and migration of OV A2780 cells. In this process, DPP4 and TXNIP are the key target, immune regulation, and oxidative stress playing significant roles.

IL-10 Enhances the Inhibitory Effect of Adipose-Derived Stromal Cells on Insulin Resistance/Liver Gluconeogenesis by Treg Cell Induction.

The modulation of cellular phenotypes within adipose tissue provides a potential means for therapeutic intervention for diabetes. Endogenous interleukin-10 (IL-10) protects against diet-induced insulin resistance. We examined the effects and mechanisms of action of IL-10-treated adipose-derived stromal cells on diabetes-induced insulin resistance and liver gluconeogenesis. We harvested stromal vascular fractions (SVFs) from the adipose tissue of diabetic (Leprdb/db) mice and treated them with IL-10 in vitro. SVFs treated with 10 or 100 ng of IL-10 were injected into the inguinal adipose tissue of Leprdb/db mice. IL-10 treatment suppressed the mRNA expression of IL-6, IL-33, CCL2, TNF-α, and IL-1ß. Additionally, it suppressed the protein expression of IL-6, pmTOR, pJNK, and pNF-κB but enhanced Foxp3 mRNA expression in SVFs from diabetic mice. Meanwhile, IL-10 treatment repressed CCL2 and PDGFRα expression in adipose tissue macrophages (ATMs) and IL-6 expression in non-ATMs but increased the Foxp3 and IL-10 mRNA expression of ATMs from diabetic mice. Injection of IL-10-treated SVFs decreased the IL-6, IL-33, CCL2, IL-1ß, and CCL2 but enhanced the Foxp3 and IL-10 mRNA expression of adipose tissue from Leprdb/db mice. Furthermore, injection of IL-10-treated SVFs increased CD4+ regulatory T cells (Tregs) in SVFs and adipose IL-10 levels and suppressed plasma adiponectin levels and DPP4 activity in diabetic mice. Injection of IL-10-treated SVFs decreased hepatic G6PC and PCK1 mRNA expression and increased Akt activation, STAT3 phosphorylation in the liver, and glucose tolerance in diabetic mice. Our data suggest that IL-10 treatment decreases inflammation in adipose SVFs of diabetic mice. Injection of IL-10-treated SVFs into the adipose tissue decreased diabetes-induced gluconeogenesis gene expression, DPP4 activity, and insulin resistance by enhancing Treg cells in diabetic mice. These data suggest that IL-10-treated adipose stromal vascular cells could be a promising therapeutic strategy for diabetes mellitus.

Sodium-glucose co-transporter-2 inhibitors versus dipeptidyl peptidase-4 inhibitors on major liver outcomes in metabolic dysfunction-associated steatotic liver disease.

AIM: To compare the effectiveness of sodium-glucose co-transporter-2 inhibitors (SGLT2is) with dipeptidyl peptidase-4 inhibitors (DPP4is) on major liver outcomes (MLO) in patients with type 2 diabetes (T2D) and metabolic dysfunction-associated steatotic liver disease (MASLD). MATERIALS AND METHODS: We included adult patients with T2D and MASLD, using metformin without specific liver conditions or surgeries, from the Merative MarketScan database. Patients initiating SGLT2is or DPP4is from 1 January 2014 to 31 December 2022 were identified. The primary outcome was time to MLO diagnosis. Overlap weighting balanced covariates, integrated with a Cox proportional hazards model for survival analysis. RESULTS: Among 44 651 patients, 22 100 initiated SGLT2is, and 22 551 began DPP4is. After weighting, the incidence rate of MLO in the SGLT2i group was 3.8 per 1000 person-years, and it was 3.9 per 1000 person-years in the DPP4i group, resulting in an adjusted hazard ratio (aHR) of 0.82 (95% CI, 0.60-1.10). SGLT2i initiation was not associated with cirrhosis (aHR: 0.77; 95% CI, 0.55-1.06) or hepatocellular carcinoma (aHR: 0.99; 95% CI, 0.47-1.83) separately. Subgroup and sensitivity analyses did not yield significant results. CONCLUSIONS: In patients with T2D and MASLD, SGLT2is did not show a lower risk of MLO compared with DPP4is. Clinicians should consider the overall patient conditions and the additional benefits of SGLT2is to support the decision to switch from DPP4is.

A case report of dipeptidyl peptidase 4 inhibitor-related kidney disease combined with renal cancer.

A kidney biopsy was performed in a 64-year-old woman with type 2 diabetes mellitus and less than 1 g of proteinuria who rapidly progressed to end-stage renal failure after approximately 2 years of treatment with two dipeptidyl peptidase 4 (DPP-4) inhibitors for type 2 diabetes mellitus. The biopsy revealed not only a coincidental diagnosis of renal cell carcinoma, which was not evident on pre-biopsy computed tomography, but also severe thrombotic microangiopathy (TMA)-like glomerular endothelial cell damage in the noncancerous areas. These results suggest that DPP4 inhibitors may have been involved in two kidney diseases.

Evaluation of glucose-lowering medications in older people: a comprehensive systematic review and network meta-analysis of randomized controlled trials.

BACKGROUND: Type 2 diabetes mellitus (T2DM) is increasingly being diagnosed in older adults. Our objective is to assess the advantages and potential drawbacks of different glucose-lowering medications in this specific population. METHODS: A network meta-analysis was conducted to identify randomized controlled trials that examined patient-centered outcomes in adults aged ≥65 years with T2DM. We searched PubMed, Cochrane CENTRAL, and Embase up to September 23, 2023. Quality of eligible studies were assessed using the Cochrane RoB 2.0 tool. RESULTS: A total of 22 trials that involved 41 654 participants were included, incorporating sodium-glucose cotransporter-2 (SGLT2) inhibitors, glucagon-like peptide-1 receptor agonists (GLP-1RAs), dipeptidyl peptidase-4 (DPP-4) inhibitors, metformin, sulfonylureas (SU) and acarbose. Our findings reveal that GLP-1RAs reduce the risk of major adverse cardiovascular events (risk ratio [RR], 0.83; 95% confidence interval [CI], 0.71 to 0.97) and body weight (mean difference [MD], -3.87 kg; 95% CI, -5.54 to -2.21). SGLT2 inhibitors prevent hospitalization for heart failure (RR, 0.66; 95% CI, 0.57 to 0.77), renal composite outcome (RR, 0.69; 95% CI, 0.53 to 0.89), and reduce body weights (MD, -1.85 kg; 95% CI, -2.42 to -1.27). SU treatment increases the risk of any hypoglycaemia (RR, 4.19; 95% CI, 3.52 to 4.99) and severe hypoglycaemia (RR, 7.06; 95% CI, 3.03 to 16.43). GLP-1RAs, SGLT2 inhibitors, metformin, SU and DPP-4 inhibitors are effective in reducing glycaemic parameters. Notably, the number of treatments needed decreases in most cases as age increases. CONCLUSIONS: Novel glucose-lowering medications with benefits that outweigh risks should be prioritized for older patients with diabetes.

Expert Consensus on Dipeptidyl Peptidase-4 Inhibitor-Based Therapies in the Modern Era of Type 2 Diabetes Mellitus Management in India.

India has a high prevalence of type 2 diabetes mellitus (T2DM) with unique clinical characteristics compared to other populations. Despite advancements in diabetes therapy, a significant number of patients in India still experience poor glycemic control and complications. Dipeptidyl peptidase-4 (DPP-4) inhibitors continue to be an important component of T2DM treatment due to their favorable efficacy and tolerability profile. Given the current scenario, there is a need to revisit the role of DPP-4 inhibitors in T2DM management in Indian patients. This consensus paper aims to provide guidance on the utilization of DPP-4 inhibitors in T2DM management from an Indian perspective. A consensus group of 100 experts developed recommendations based on an extensive literature review and discussions. The expert group emphasized the importance of timely glycemic control, combination therapy, and targeting the underlying pathophysiology of T2DM. The combinations of DPP-4 inhibitors with metformin and/or sodium-glucose transport protein-2 inhibitors are rationalized in this paper, considering their complementary mechanisms of action. This paper provides valuable insights for clinicians in optimizing the management of T2DM in the Indian population with the use of DPP-4 inhibitors and proposes an algorithm for selecting DPP-4 inhibitor-based therapies.

Safety of SGLT2 inhibitors, DPP-4 inhibitors, and GLP-1 receptor agonists in US veterans with and without chronic kidney disease: a population-based study.

Background: We examined the real-world comparative safety of sodium-glucose cotransporter-2 inhibitors (SGLT2i) vs. other newer anti-glycemic medications (dipeptidyl peptidase-4 inhibitors [DPP4i], glucagon-like peptide-1 receptor agonists [GLP1a]) in patients with and without chronic kidney disease (CKD). Methods: Among US Veterans with diabetes receiving care from the Veterans Affairs (VA) healthcare system over 2004-19, we identified incident users of SGLT2i vs. DPP4i vs. GLP1a monotherapy. In analyses stratified by CKD status, defined by estimated glomerular filtration rate and albuminuria, we examined associations of SGLT2i vs. DPP4i vs. GLP1a use with risk of infection-related (primary outcome) and genitourinary infection hospitalizations (secondary outcome) using multivariable Cox models. Findings: Among 92,269 patients who met eligibility criteria, 52% did not have CKD, whereas 48% had CKD. In the overall and non-CKD cohorts, compared to DPP4i use, SGLT2i use was associated with lower infection-related hospitalization risk (HRs [95% CIs] 0.74 [0.67-0.81] and 0.77 [0.67, 0.88], respectively), whereas GLP1a use demonstrated comparable risk. However, in the CKD cohort SGLT2i and GLP1a use were each associated with lower risk (HRs [95% CIs] 0.70 [0.61, 0.81] and 0.91 [0.84, 0.99], respectively). Propensity score-matched analyses showed similar findings in the non-CKD and CKD cohorts. In the overall, non-CKD, and CKD cohorts, SGLT2i use was associated with lower genitourinary infection hospitalization risk whereas GLP1a use showed comparable risk vs. DPP4i use. Interpretation: In a national cohort of Veterans with diabetes, compared with DPP4i use, SGLT2i use was associated with lower infection-related and genitourinary infection hospitalization risk. Funding: VA Health Services Research and Development, USA.

Bis(benzimidazol-2-yl)amine-based DPP-4 Inhibitors Potentially Suitable for Combating Diabetes and Associated Nervous System Alterations.

Bis(benzimidazol-2-yl)amine scaffold is not present in dipeptidyl peptidase-4 (DPP-4) inhibitors published so far. Herein, the inhibitory potential of bis(benzimidazol-2-yl)amine derivatives against DPP-4 was evaluated. In non-competitive inhibition mode, three representatives 5, 6, and 7 inhibited DPP-4 in vitro with IC50 values below 50 µM. The assessed binding pocket of DPP-4 for these benzimidazoles includes the S2 extensive subsite's residues Phe357 and Arg358. None of the lead compounds showed cytotoxicity to human neuroblastoma SH-SY5Y cells at concentrations lower than 10 µM. None showed significant binding affinity for dopamine D2, D3, and histamine H1, H3 receptors, at concentrations lower than 10 µM, leading to preferable outcomes due to mutually opposite effects of these neurotransmitters on each other. The potential beneficial effects on dopamine synthesis and the survival of dopaminergic neurons could be mediated by DPP-4 inhibition. These effective noncompetitive DPP-4 inhibitors, with inhibitory potential better than reference diprotin A (relative inhibitory potency compared to diprotin A is 3.39 and 1.54 for compounds 7 and 5, respectively), with the absence of the cytotoxicity to SH-SY5Y cells, are valuable candidates for further evaluation for the treatment of diabetes and associated disruption of neuronal homeostasis.

Adherence and persistence among people with type 2 diabetes newly initiating oral semaglutide versus DPP-4is in a US real-world setting.

AIMS: To investigate real-world treatment adherence and persistence in people with type 2 diabetes newly initiating oral semaglutide, a glucagon-like peptide-1 receptor agonist (GLP-1 RA), or a dipeptidyl peptidase-4 inhibitor (DPP-4i). METHODS: This retrospective cohort study used the Merative™ MarketScan® Commercial and Medicare databases. Index date was the first fill for the cohort medication. Adherence was defined as proportion of days covered (PDC) over the 12-month post-index period ('adherent' = ≥0.8). Persistence was number of days until discontinuation, based on a 45-day gap. Results were compared between cohorts using inverse probability treatment weighting. RESULTS: Oral semaglutide (n=5485) and DPP-4i (n=4980) cohorts had similar percentages of people who were adherent (PDC ≥0.8; 41.6 % vs. 42.9 %; P = 0.182) and persistent for ≥9 months (45.0 % vs. 46.3 %; P = 0.185). The DPP-4i cohort used significantly more anti-diabetic medication (ADM) classes over the post-index period (mean±SD: 2.6±1.0 vs. 2.9±1.1, P < 0.001), with 23.2 % filling a GLP-1 RA in the post-period. CONCLUSIONS: Adherence and persistence were similar between cohorts. However, there are potential benefits to prescribing oral semaglutide over DPP-4is, including reduced need for additional ADM.

Acute Pancreatitis With Normal Amylase and Lipase: A Diagnostic Dilemma.

Acute pancreatitis is a common and potentially life-threatening condition. It is characterized by inflammation of the pancreas, most often leading to elevated levels of pancreatic enzymes in the blood. In a subset of patients, however, conventional biomarker levels may remain within the reference range. Such instances have the potential to create a diagnostic challenge for healthcare professionals and can lead to misdiagnosis or delayed treatment. This article presents the intriguing clinical scenario of acute pancreatitis with normal amylase and lipase, discusses factors that may lead to normoenzymatic presentation, and reminds clinicians of the diagnostic criteria for acute pancreatitis, which does not necessarily require elevated pancreatic enzymes.

Soluble CD26: From Suggested Biomarker for Cancer Diagnosis to Plausible Marker for Dynamic Monitoring of Immunotherapy.

Soluble CD26 (sCD26), a glycoprotein with dipeptidyl peptidase (DPP4) enzymatic activity, can contribute to early diagnosis of colorectal cancer and advanced adenomas and has been studied, including for prognostic purposes, across various other types of cancer and disease. The latest research in this field has confirmed that most, though not all, serum/plasma sCD26 is related to inflammation. The shedding and/or secretion of sCD26 from different immune cells are being investigated, and blood DPP4 activity levels do not correlate very strongly with protein titers. Some of the main substrates of this enzyme are key chemokines involved in immune cell migration, and both soluble and cell-surface CD26 can bind adenosine deaminase (ADA), an enzyme involved in the metabolism of immunosuppressor extracellular adenosine. Of note, there are T cells enriched in CD26 expression and, in mice tumor models, tumor infiltrating lymphocytes exhibited heightened percentages of CD26+ correlating with tumor regression. We employed sCD26 as a biomarker in the follow-up after curative resection of colorectal cancer for the early detection of tumor recurrence. Changes after treatment with different biological disease-modifying antirheumatic drugs, including Ig-CTLA4, were also observed in rheumatoid arthritis. Serum soluble CD26/DPP4 titer variation has recently been proposed as a potential prognostic biomarker after a phase I trial in cancer immunotherapy with a humanized anti-CD26 antibody. We propose that dynamic monitoring of sCD26/DPP4 changes, in addition to well-known inflammatory biomarkers such as CRP already in use as informative for immune checkpoint immunotherapy, may indicate resistance or response during the successive steps of the treatment. As tumor cells expressing CD26 can also produce sCD26, the possibility of sorting immune- from non-immune-system-originated sCD26 is discussed.

Sitagliptin exhibits protective effects against methotrexate-induced testicular toxicity: The involvement of oxidative stress-related factors.

Methotrexate (MTX) is widely prescribed to treat different malignancies as well as autoimmune diseases. However, it causes a range of side effects in different organs such as testis. This study aims to clarify the role of dipeptidyl peptidase 4 (DPP4) in MTX-induced testicular damage via pathways involved in oxidative stress and evaluates the protective effects of sitagliptin as a DPP4 inhibitor. Twenty-four animals randomly allocated into four groups including: (I) control, (II) MTX (20 mg/kg, i.p.), (III) sitagliptin (20 mg/kg, i.p., for four consecutive days), and MTX + sitagliptin in which received chemicals resembling group II and III. Histopathological examinations conducted to assess the structural changes in testes of different experimental groups. Also, ELISA method employed to investigate the levels of DPP4, AKT, p-AKT, nuclear factor erythroid 2-related factor 2 (Nrf2), and heme oxygenase-1 (HO-1). In addition, the total malondialdehyde (MDA) content and the activity of superoxide dismutase (SOD) were assessed. The results indicated that MTX administration was accompanied with testicular damage, which reversed by sitagliptin treatment. The biochemical observations demonstrated that MTX markedly increased the levels of DPP4, decreased p-AKT/AKT ratio followed by a marked decrement in Nrf2 and HO-1 levels. Also, it was observed that MTX decreased the activity of SOD and increased total MDA content in testicular specimen. However, sitagliptin treatment diminished mentioned alterations effectively. Altogether, our findings supported the possible role of DPP4 in MTX-induced testicular toxicity along with the potential protective features of sitagliptin via suppressing of the histopathological and biochemical alterations induced by MTX.

Glucagon-like peptide-1 receptor agonists and sodium-glucose cotransporter-2 inhibitors for the treatment of diabetes mellitus in liver transplant recipients.

AIM: To investigate the efficacy and safety of glucagon-like peptide-1 receptor agonists (GLP-1RAs) and sodium-glucose cotransporter-2 (SGLT2) inhibitors in liver transplant (LT) recipients with diabetes. METHODS: A single-centre, retrospective analysis of prospectively collected data from an LT recipient database (1990-2023) was conducted. We included adults with pre-existing diabetes and post-transplant diabetes, newly started on GLP-1RAs and/or SGLT2 inhibitors after LT. Metabolic and biochemical parameters and outcomes were collected for up to 12 months after starting medications and were compared to those in patients receiving dipeptidyl peptidase-4 (DPP-4) inhibitors. Statistical analysis included descriptive statistics and linear mixed models. RESULTS: We included participants on GLP-1RAs (n = 46), SGLT2 inhibitors (n = 87), combination therapy (n = 12), and a DPP-4 inhibitor comparator (n = 217). Both GLP-1RAs and combination therapy decreased mean glycated haemoglobin (HbA1c) levels, and combination therapy remained significant when adjusted for DPP-4 inhibitor treatment (-3.5%, 95% CI [-6.1, -0.95]; p = 0.0089) at 12 months. All three groups had significant decreases in mean weight and body mass index, but these remained significant in the GLP-1RA (-5.2 kg, 95% CI [-8.7, -1.7], p = 0.0039 and 1.99 kg/m2, 95% CI [-3.4, -0.6], p = 0.0048) and combination therapy groups (-5.4 kg, 95% CI [-10.5, -0.36], p = 0.04 and -3.4 kg/m2, 95% CI [-5.5, -1.3], p = 0.0015) when adjusted for DPP-4 inhibitor treatment at 12 months. Alanine aminotransferase levels decreased with GLP-1RA and combination therapy. There were two (1.4%) cases of graft rejection. CONCLUSION: We found that GLP-1RAs, SGLT2 inhibitors, and their combination, led to significant weight loss in LT recipients with diabetes. Combination therapy, in particular, lowered HbA1c and alanine aminotransferase levels compared to DPP-4 inhibitors. Further studies are needed to assess long-term safety and efficacy.

Advances in small-molecule insulin secretagogues for diabetes treatment.

Diabetes, a metabolic disease caused by abnormally high levels of blood glucose, has a high prevalence rate worldwide and causes a series of complications, including coronary heart disease, stroke, peripheral vascular disease, end-stage renal disease, and retinopathy. Small-molecule compounds have been developed as drugs for the treatment of diabetes because of their oral advantages. Insulin secretagogues are a class of small-molecule drugs used to treat diabetes, and include sulfonylureas, non-sulfonylureas, glucagon-like peptide-1 receptor agonists, dipeptidyl peptidase 4 inhibitors, and other novel small-molecule insulin secretagogues. However, many small-molecule compounds cause different side effects, posing huge challenges to drug monotherapy and drug selection. Therefore, the use of different small-molecule drugs must be improved. This article reviews the mechanism, advantages, limitations, and potential risks of small-molecule insulin secretagogues to provide future research directions on small-molecule drugs for the treatment of diabetes.

Gut microbiota DPP4-like enzymes are increased in type-2 diabetes and contribute to incretin inactivation.

BACKGROUND: The gut microbiota controls broad aspects of human metabolism and feeding behavior, but the basis for this control remains largely unclear. Given the key role of human dipeptidyl peptidase 4 (DPP4) in host metabolism, we investigate whether microbiota DPP4-like counterparts perform the same function. RESULTS: We identify novel functional homologs of human DPP4 in several bacterial species inhabiting the human gut, and specific associations between Parabacteroides and Porphyromonas DPP4-like genes and type 2 diabetes (T2D). We also find that the DPP4-like enzyme from the gut symbiont Parabacteroides merdae mimics the proteolytic activity of the human enzyme on peptide YY, neuropeptide Y, gastric inhibitory polypeptide (GIP), and glucagon-like peptide 1 (GLP-1) hormones in vitro. Importantly, administration of E. coli overexpressing the P. merdae DPP4-like enzyme to lipopolysaccharide-treated mice with impaired gut barrier function reduces active GIP and GLP-1 levels, which is attributed to increased DPP4 activity in the portal circulation and the cecal content. Finally, we observe that linagliptin, saxagliptin, sitagliptin, and vildagliptin, antidiabetic drugs with DPP4 inhibitory activity, differentially inhibit the activity of the DPP4-like enzyme from P. merdae. CONCLUSIONS: Our findings confirm that proteolytic enzymes produced by the gut microbiota are likely to contribute to the glucose metabolic dysfunction that underlies T2D by inactivating incretins, which might inspire the development of improved antidiabetic therapies.