Cardiovascular effects of sitagliptin - An anti-diabetes medicine

Adverse Cardiac Events of Hypercholesterolemia Are Enhanced by Sitagliptin Administration in Sprague Dawley Rats

Background

Cardiovascular disease (CVD) affects millions worldwide and is the leading cause of death among non-communicable diseases. Western diets typically comprise of meat and dairy products, both of which are rich in cholesterol (Cho) and methionine (Met), two well-known compounds with atherogenic capabilities. Despite their individual effects, literature on a dietary combination of the two in the context of CVD are limited. An additional interest was to investigate the cardioprotective potential of sitagliptin, an anti-type 2 diabetic drug. Thus, we hypothesized that atherogenic feeding would result in adverse cardiac effects and would attenuate upon sitagliptin administration.

Methods

Six-week-old adult male Sprague-Dawley rats were fed either a control (Con), high Met (1.5%), high Cho (2.0%), or high Met (1.5%) + high Cho (2.0%) diet for 35 days. They were orally gavaged with vehicle (water) or sitagliptin (100 mg/kg/d) from day 10 through 35. On day 36, rats were euthanized, and tissues were collected for analysis.

Results

Histopathological evaluation revealed a reduction in myocardial striations and increased collagen deposition in hypercholesterolemia (HChol), responses that became exacerbated upon sitagliptin administration. Cardiac pro-inflammatory and pro-fibrotic responses were adversely impacted in similar fashion. The addition of Met to Cho (MC) attenuated all adverse structural and biochemical responses, with or without sitagliptin.

Conclusion

Adverse cardiac outcomes in HChol were enhanced with sitagliptin administration and such effects were alleviated by Met. Our findings could be significant for understanding the risk-benefit of sitagliptin in type 2 diabetics who are known to consume atherogenic diets.

Identification and screening of potential inhibitors obtained from Plumeria rubra L. compounds against type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is the inability of the body's cells to retaliate to insulin, which can periodically culminate into absolute insulin deficiency. Hyperinsulinemia can be alleviated by administering oral medications or insulin. Prevailing medicaments engender repercussions with prolonged use, as they transmute to an inefficacious form. Hence, it will be advantageous to design plant-derived antihyperglycemic drugs with remarkable efficacy and safety quotients to address T2DM and associated comorbidities. Based on prior research, we have identified 7 novel phytocompounds from Plumeria rubra L. and 5 co-crystals that serve as an important residence for T2DM. The compounds are assessed for their inhibitory activity and dynamic stability against five major receptors which are responsible for T2DM. Additionally, in silico ADMET assessment followed by GPU-enabled GROMACS was performed on the selected compounds. The results demonstrated that β-d-Hexaglucoside had the highest binding affinity, hydrophobicity and bond length in contrast to all the targeted receptors. β-d-Hexaglucoside was subjected to dynamic simulation to analyze the root mean square deviation and root mean square fluctuation graph rates using the GROMOS force field in GROMACS software. Furthermore, β-d-Hexaglucoside exhibited inhibitory activity against diabetic receptors with a docking score of -9.5 kcal/mol. The current study proposes β-d-Hexaglucoside as a potential candidate for in-vitro or pre-clinical investigations to ameliorate T2DM management.Communicated by Ramaswamy H. Sarma.

Crosstalk between autophagy and insulin resistance: evidence from different tissues

Insulin is a critical hormone that promotes energy storage in various tissues, as well as anabolic functions. Insulin resistance significantly reduces these responses, resulting in pathological conditions, such as obesity and type 2 diabetes mellitus (T2DM). The management of insulin resistance requires better knowledge of its pathophysiological mechanisms to prevent secondary complications, such as cardiovascular diseases (CVDs). Recent evidence regarding the etiological mechanisms behind insulin resistance emphasizes the role of energy imbalance and neurohormonal dysregulation, both of which are closely regulated by autophagy. Autophagy is a conserved process that maintains homeostasis in cells. Accordingly, autophagy abnormalities have been linked to a variety of metabolic disorders, including insulin resistance, T2DM, obesity, and CVDs. Thus, there may be a link between autophagy and insulin resistance. Therefore, the interaction between autophagy and insulin function will be examined in this review, particularly in insulin-responsive tissues, such as adipose tissue, liver, and skeletal muscle.

Discovery and Structural Optimization of 1,2,3,4-Tetrahydro-β-carbolines as Novel Reactive Oxygen Species Inducers for Controlling Intractable Plant Bacterial Diseases

Nowadays, reactive oxygen species (ROS) have been acknowledged as promising bactericidal targets against pesticide-resistant bacteria. Herein, to further excavate more excellent ROS inducers, simple 1,2,3,4-tetrahydro-β-carboline derivatives containing a 3-aminopropanamide moiety were prepared and assessed for their antibacterial potency. Notably, three promising compounds displayed significant antibacterial potency. Compound I₂₉ exhibits excellent in vitro bioactivity, with an EC₅₀ value of 5.73 μg/mL, and admirable in vivo activities (protective activity of 55.74% and curative activity of 65.50%) toward Xanthomonas oryzae pv. oryzae. Compound I₁₆ has good activity in vitro, with an EC₅₀ of 3.43 μg/mL, and outstanding bioactivities in vivo (protective activity of 92.50% and curative activity of 59.68%) against Xanthomonas axonopodis pv. citri. Compound I₆ shows excellent in vitro bioactivity (EC₅₀ = 2.86 μg/mL) and significant protective activity (94.02%) for preventing Pseudomonas syringae pv. actinidiae. Antibacterial mechanism investigations indicate that these compounds disrupt the balance of the redox system to kill bacteria. These simple 1,2,3,4-tetrahydro-β-carboline derivatives are promising leads to the discovery of bactericidal agents.

Continuous Glucose Monitoring as an Additional Tool in Early Cystic Fibrosis-Related Diabetes Monitoring and in Evaluation of Short-Term Sitagliptin Response

Cystic fibrosis-related diabetes (CFRD) is a complication associated with a negative prognosis in patients with cystic fibrosis (CF). Although the oral glucose tolerance test (OGTT) is the widely recommended screening test for CFRD diagnosis, continuous glucose monitoring (CGM) is increasingly considered a useful and easy-to-perform test for diagnosis and follow-up in clinical practice. Regarding CFRD treatment, although insulin is the classic approved pharmacological option, incretins could also be a helpful alternative in early stages. CGM could be also a useful tool to measure the early response to this therapy.

METHODS

We studied 25 CF patients with abnormal OGTT results and compared glucose and insulin levels during the OGTTs with CGM results as a tool for early CFRD diagnosis. In addition, we evaluated glycaemic control with CGM before and after treatment with sitagliptin.

RESULTS

A correlation was found between lower plasma insulin levels during the OGTTs and higher average sensor glucose (p = 0.009) and hyperglycaemic excursions (p = 0.017). The CGM data on sitagliptin treatment (n = 25) showed an average glycaemic improvement from 124.2 to 117.2 mg/dL (p = 0.002) with a 5.6-point standard deviation of glucose decrease (p < 0.001). Hyperglycaemic excursions ≥200 mg/dL diminished 57.1% (p = 0.021). Both time in range and time above 180 mg/dL improved during treatment (p = 0.036 and p = 0.006, respectively).

CONCLUSION

CGM is a useful tool that offers valuable information for both the diagnosis and the management of CFRD. Lower plasma insulin levels during OGTTs are associated with a poor ambulatory glucose profile in CGM. Sitagliptin could play an important role in the treatment of the early stages of CFRD.

Sitagliptin Potentiates the Anti-Neoplastic Activity of Doxorubicin in Experimentally-Induced Mammary Adenocarcinoma in Mice: Implication of Oxidative Stress, Inflammation, Angiogenesis, and Apoptosis

Sitagliptin (STG) is a highly selective dipeptidyl peptidase-4 inhibitor recently used in the treatment of type 2 diabetes. The current study aimed to investigate the anti-neoplastic effect of STG alone and in combination with Doxorubicin (Dox), a known chemotherapeutic agent but with ominous side effects. After intramuscular inoculation of 2 × 106 Ehrlich tumor cells, Female Swiss mice were divided into tumor-bearing control, STG-treated, Dox-treated, and a combination of STG and Dox-treated groups. The results showed a significant reduction in the tumor growth of the treated animals in comparison with those of the positive control group with a more prominent effect in the co-treated group. Where, the anti-proliferative and apoptotic effect of STG, and its chemo-sensitizing ability, when used in combination with Dox, was mediated by modulation of oxidative stress (MDA and GSH), attenuation of tumor inflammation (IL-6 and IL-1β), and angiogenesis (VEGF), suppressing proliferation (β-catenin and cyclin-D1) and enhancement of apoptosis (survivin, p53, caspase 3). Thus, in conclusion, STG as adjunctive therapy for Dox could be a strategy for the treatment of breast cancer patients, by their ability in hindering cell proliferation and minimizing the associated oxidative and inflammatory adverse reactions.

The Impact of Hypoglycemic Therapy on the Prognosis for Acute Coronary Syndrome in Patients with Type 2 Diabetes

The article discusses particular circumstances of acute coronary syndrome (ACS) in patients with type 2 diabetes (T2D). In addition, the available literature data and clinical guidelines reflecting the role of hypoglycemic therapy as a cardioprotection factor in ACS are analyzed. The article considers possible protective molecular mechanisms of various groups of drugs in ischemic cardiomyocytes.

Effects of sitagliptin on serum lipid levels in patients with type 2 diabetes: a systematic review and meta-analysis

AIM

Lipid abnormalities often occur in patients with diabetes mellitus and the coexistence of diabetes mellitus and dyslipidaemia will increase the risk of cardiovascular diseases. However, the specific effects of sitagliptin on lipid control remain elusive in diabetic patients. The aim of this meta-analysis is to investigate the effects of sitagliptin alone or with other antidiabetic agents on serum lipid control.

METHODS

PubMed, Cochrane Library, Embase and the ClinicalTrials.gov website were systematically searched from 2006 (the first year that sitagliptin entered market) to 16 January 2021. Eligible studies were randomized clinical trials (RCTs) of sitagliptin including outcomes of serum total cholesterol (TC), triglycerides, high-density lipoprotein cholesterol (HDL-C) or low-density lipoprotein cholesterol (LDL-C).

RESULTS

A total of 14 RCTs with 2654 patients were identified. Treatment with sitagliptin alone or in combination with other antidiabetic agents significantly reduced serum TC [mean difference (MD) = -5.52 95% confidence interval (95% CI), -7.88 to -3.15; P < 0.00001] and LDL-C (MD = -0.07; 95% CI, -0.14 to 0.00; P < 0.00001) in patients with type 2 diabetes. No statistical significances were found in serum triglycerides (MD = 1.53; 95% CI, -8.22 to 11.28; P = 0.76) or HDL-C (MD = 0.65; 95% CI, -1.59 to 0.29; P = 0.18). Subgroup analyses suggest that sitagliptin can significantly decrease serum LDL-C, TC and triglyceride levels compared with placebo alone, and no statistical significance was found in comparison with the serum HDLC levels.

CONCLUSION

Sitagliptin alone or in combination with other antidiabetic agents significantly reduces serum TC and LDL-C in patients with type 2 diabetes mellitus, while no significant difference was observed in serum triglycerides or HDL-C.

Sitagliptin protects renal glomerular endothelial cells against high glucose-induced dysfunction and injury

Sitagliptin is a well-established anti-diabetic drug that also exerts protective effects on diabetic complications. Previous work reveals that sitagliptin has a protective effect on diabetic nephropathy (DN). Vascular impairment frequently occurs in diabetic renal complications. Here, we evaluated the protective function of sitagliptin in human renal glomerular endothelial cells (HrGECs) under high glucose (HG) conditions. Expressions of the pro-inflammatory cytokines interleukin-1β (IL-1β) and interleukin-8 (IL-8) were assessed using real-time PCR and ELISA. Endothelial cells permeability was assayed using the fluorescein isothiocyanate dextran (FITC-dextran) and trans-endothelial electrical resistance (TEER) assay. The results show that sitagliptin mitigated HG-induced oxidative stress in HrGECs with decreased levels of mitochondrial reactive oxygen species (ROS), Malondialdehyde (MDA), and 8-hydroxydeoxyguanosine (8-OHdG). Sitagliptin inhibited HG-induced production of pro-inflammatory cytokines interleukin-1β (IL-1β) and interleukin-8 (IL-8) in HrGECs. It also ameliorated HG-induced aggravation of HrGECs permeability and reduction of the tight junction component claudin-5. Moreover, kruppel Like Factor 6 (KLF6) mediated the protective effects of sitagliptin on endothelial monolayer permeability against HG. Collectively, sitagliptin reversed the HG-induced oxidative stress, inflammation, and increased permeability in HrGECs via regulating KLF6. This study suggests that sitagliptin might be implicated as an effective strategy for preventing diabetic renal injuries in the future.

Cardioprotective Effect of Quercetin and Sitagliptin in Doxorubicin-Induced Cardiac Toxicity in Rats

Objective

A previous study revealed a pronounced protective effect of combining quercetin (QC) with sitagliptin (STN) in testicular tissue. Accordingly, this study was designed to evaluate the cardioprotective effects of QC and STN each alone or in combination in doxorubicin (DOX)-induced cardiotoxicity in the rats.

Methodology

Thirty male adult Wistar rats were divided into five groups: the first group (control) treated with sodium chloride, the second group treated with DOX (3 mg/kg I.P. injection), the third group treated with DOX with a combination of QC (80 mg/kg), and STN (10 mg/kg), the fourth group treated with DOX and QC and the fifth group treated with DOX and STN. Blood was collected on day 22 and used for assessment of serum troponin, lactate dehydrogenase (LDH), creatine phosphokinase (CPK), total lipid profile, C-reactive protein (CRP), and total antioxidant capacity (TAOC). Atherogenic indices were also calculated. Cardiac tissue was sent for histopathological analysis.

Results

DOX produced a significant increase in the level of troponin, LDH, CKP, CRP, total cholesterol (TC), low-density lipoprotein (LDL), triglycerides (TG), and atherogenic index of plasma; and significantly decreased TAOC. The combination of quercetin and sitagliptin was more effective than each treatment alone in restoring the level of troponin, LDH, CKP, CRP, Cholesterol, LDL, TG, atherogenic index of plasma and significantly increased TAOC compared to DOX treated group. The histopathological finding also supports the biochemical results.

Conclusion

The study revealed the cardioprotective effects of the combination of QC and STN which could be attributed to the additive effects of this combination through antioxidant, anti-inflammatory, lipid lowering and anti-atherogenic activities; suggesting it as a good therapeutic candidate to be tested in the clinical setting.

Dipeptidyl peptidase-4 inhibitor sitagliptin induces vasorelaxation via the activation of Kv channels and PKA

The present study investigated the vasorelaxant effects of sitagliptin, which is a dipeptidyl peptidase-4 (DPP-4) inhibitor in aortic rings pre-contracted with phenylephrine (Phe). Sitagliptin induced vasorelaxation in a concentration-dependent manner but the inhibition of voltage-dependent K⁺ (Kv) channels by pretreatment with 4-aminopyridine (4-AP) effectively reduced this effect. By contrast, the inhibition of inward rectifier K⁺ (Kir) channels by pretreatment with barium (Ba²⁺), large-conductance calcium (Ca²⁺)-activated K⁺ (BK_Ca) channels with paxilline, and adenosine triphosphate (ATP)-sensitive K⁺ (K_ATP) channels with glibenclamide did not change this effect. Although the application of SQ 22536, which is an adenylyl cyclase inhibitor, also did not change this effect, treatment with KT 5720, a protein kinase A (PKA) inhibitor, effectively reduced the vasorelaxant effects of sitagliptin. ODQ, which is a guanylyl cyclase inhibitor, and KT 5823, a protein kinase G (PKG) inhibitor, did not impact the effect. Furthermore, neither the inhibition of Ca²⁺ channels by pretreatment with nifedipine nor the inhibition of sarcoplasmic/endoplasmic reticulum Ca²⁺-ATPase (SERCA) pumps by pretreatment with thapsigargin changed the effect. Similarly, the effects of sitagliptin were not altered by eliminating the endothelium, by pretreatment with a nitric oxide (NO) synthase inhibitor (L-NAME), or by inhibition of small- and intermediate-conductance Ca²⁺-activated K⁺ channels (SK_Ca and IK_Ca) using apamin and TRAM-34. Taken together, these results suggest that sitagliptin induces vasorelaxation by inhibiting both membrane potential (Em)-dependent and -independent vasoconstriction and activating PKA and Kv channels independently of PKG signaling pathways, other K⁺ channels, SERCA pumps, and the endothelium.

Sitagliptin promotes mitochondrial biogenesis in human SH-SY5Y cells by increasing the expression of PGC-1α/NRF1/TFAM

Mitochondrial dysfunction has been associated with the pathogenesis of a variety of neurodegenerative diseases. Sitagliptin is a dipeptidyl-peptidase-4 (DPP-4) inhibitor that has been approved for the treatment of type 2 diabetes (T2DM). In the current study, we report that sitagliptin increased the expression of PGC-1α, NRF1, and TFAM in human SH-SY5Y neuronal cells. Notably, our data indicate that sitagliptin promoted mitochondrial biogenesis by increasing the amount of mtDNA, the levels of mitochondria-related genes such as TOMM20, TOMM40, TIMM9, NDUFS3, ATP5C1, and the expression of oxidative phosphorylation subunits complex I and complex IV. Additionally, we found that sitagliptin induced a "gain of mitochondrial function" in SH-SY5Y cells by increasing the mitochondrial respiratory rate and adenosine triphosphate (ATP) production. Significantly, our results demonstrate that sitagliptin activated the transcriptional factor CREB by inducing its phosphorylation at Ser133. Inhibition of CREB using its specific inhibitor H89 abolished the effects of sitagliptin on the expression of PGC-1α, NRF1, and TFAM, as well as an increase in mtDNA amount and ATP production. These findings suggest that sitagliptin could become a potential agent for the treatment of neurological disorders.

Effects of Thiazolidinedione and New Antidiabetic Agents on Stroke

Patients with hyperglycemia are at a high risk of cardio- and cerebrovascular diseases. Diabetes patients also have poor outcomes after cerebrovascular disease development. Several classes of drugs are used for diabetes management in clinical practice. Thiazolidinedione (TZD) was introduced in the late 1990s, and new antidiabetic agents have been introduced since 2000. After issues with rosiglitazone in 2007, the U.S. Food and Drug Administration strongly recommended that trials investigating cardiovascular risk associated with new antidiabetic medications should be conducted before drug approval in the United States, to prove the safety of these new drugs and to determine their superiority to previous medications. Currently, results are available from two studies with TZD focusing on cardiovascular diseases, including stroke, and from 12 cardiovascular outcome trials focusing on major adverse cardiovascular events associated with new antidiabetic agents (four with dipeptidyl peptidase-4 inhibitors, three with sodium-glucose cotransporter-2 inhibitors, and five with glucagon-like peptide-1 analogues). These studies showed different results for primary cardiovascular outcomes and stroke prevention. It is important to determine whether prescription of TZD or new antidiabetic medications compared to conventional treatment, such as sulfonylurea or insulin, is better for stroke management. Furthermore, it is unclear whether drugs in the same class show greater safety and efficacy than other drugs for stroke management.