Vildagliptin, but not glibenclamide, increases circulating endothelial progenitor cell number: a 12-month randomized controlled trial in patients with type 2 diabetes

Effect of dipeptidyl peptidase-4 inhibitors on tumor necrosis factor alpha levels in patients with type 2 diabetes mellitus

AIMS

Dipeptidyl peptidase-4 inhibitors (DPP-4i) served as oral antidiabetic agents for treatment of type 2 diabetes mellitus (T2DM). Although an action on glucose homeostasis was identified, no well-rounded illustration had been established on the changes of tumor necrosis factor alpha (TNF-alpha) levels during DPP-4i treatment. This study aimed to explore the anti-inflammatory effect of DPP-4i on TNF-alpha in patients with T2DM.

METHODS

PubMed, Embase and Cochrane Library were systematically searched from inception to May 31, 2024. Randomized controlled trials exploring the impact of DPP-4i on TNF-alpha levels were identified. Risk of bias was assessed according to the Cochrane criteria. A fixed or random-effects model was selected to pool estimate on whether the heterogeneity was present. Subgroup analysis were performed to explore the potential factors that influenced heterogeneity. Related meta-analysis was conducted with the software of Revman 5.3 and STATA 12.0.

RESULTS

Eleven trials involving 884 participants with T2DM were included. Pooled estimates suggested that DPP-4i did not significantly modulate TNF-alpha levels (WMD, - 0.70, 95% CI - 1.94 to 0.53, P = 0.26) in T2DM. DPP-4i produced a significant effect on TNF-alpha (WMD, - 4.50 pg/mL, 95% CI - 4.68 to - 4.32, P < 0.00001) when compared to placebo, and a comparable effect was demonstrated on TNF-alpha (WMD, 0.10 pg/mL, 95% CI - 0.11 to 0.30, P = 0.35) in comparison with active agents. Estimate was stable according to the sensitivity test. Subgroup analysis revealed that heterogeneity might not correlate with baseline glycated hemoglobin (HbA1c), age or treatment duration.

CONCLUSIONS

A significant effect of DPP-4i on TNF-alpha levels was present in T2DM when compared to placebo. Administration of DPP-4i produced no significant effect on TNF-alpha in comparison with active comparators. Further studies with large samples should be performed to illustrate the impact of DPP-4i on TNF-alpha levels in T2DM. Trial registration International Prospective Register for Systematic Review (PROSPERO) number: CRD42020185479.

Effect of DPP-4i inhibitors on renal function in patients with type 2 diabetes mellitus: a systematic review and meta-analysis of randomized controlled trials

AIMS

About 20-40% patients with type 2 diabetes mellitus (T2DM) had an increased risk of developing diabetic nephropathy (DN). Dipeptidyl peptidase-4 inhibitors (DPP-4i) were recommended for treatment of T2DM, while the impact of DPP-4i on renal function remained unclear. This study aimed to explore the effect of DPP-4i on renal parameter of estimated glomerular filtration rate (eGFR) and albumin-to-creatinine ratio (ACR) in T2DM.

METHODS

A systematic search was performed across PubMed, Embase and Cochrane Library. A fixed or random-effects model was used for quantitative synthesis according to the heterogeneity, which was assessed with I2 index. Sensitivity analysis and publication bias were performed with standard methods, respectively.

RESULTS

A total of 17 randomized controlled trials were identified. Administration of DPP-4i produced no significant effect on eGFR (WMD, -0.92 mL/min/1.73m2, 95% CI, -2.04 to 0.19) in diabetic condition. DPP-4i produced a favorable effect on attenuating ACR (WMD, -2.76 mg/g, 95% CI, -5.23 to -0.29) in patients with T2DM. The pooled estimate was stable based on the sensitivity test. No publication bias was observed according to Begg's and Egger's tests.

CONCLUSIONS

Treatment with DPP-4i preserved the renal parameter of eGFR in diabetic condition. Available evidences suggested that administration of DPP-4i produced a favorable effect on attenuating ACR in patients with T2DM. INTERNATIONAL PROSPECTIVE REGISTER FOR SYSTEMATIC REVIEW (PROSPERO) NUMBER: CRD.42020144642.

The Impact of Modern Anti-Diabetic Treatment on Endothelial Progenitor Cells

Diabetes is one of the leading chronic diseases globally with a significant impact on mortality. This condition is associated with chronic microvascular and macrovascular complications caused by vascular damage. Recently, endothelial progenitor cells (EPCs) raised interest due to their regenerative properties. EPCs are mononuclear cells that are derived from different tissues. Circulating EPCs contribute to regenerating the vessel's intima and restoring vascular function. The ability of EPCs to repair vascular damage depends on their number and functionality. Diabetic patients have a decreased circulating EPC count and impaired EPC function. This may at least partially explain the increased risk of diabetic complications, including the increased cardiovascular risk in these patients. Recent studies have confirmed that many currently available drugs with proven cardiovascular benefits have beneficial effects on EPC count and function. Among these drugs are also medications used to treat different types of diabetes. This manuscript aims to critically review currently available evidence about the ways anti-diabetic treatment affects EPC biology and to provide a broader context considering cardiovascular complications. The therapies that will be discussed include lifestyle adjustments, metformin, sulphonylureas, gut glucosidase inhibitors, thiazolidinediones, dipeptidyl peptidase 4 inhibitors, glucagon-like peptide 1 receptor analogs, sodium-glucose transporter 2 inhibitors, and insulin.

Endothelial progenitor cells as biomarkers of diabetes-related cardiovascular complications

Diabetes mellitus (DM) constitutes a chronic metabolic disease characterized by elevated levels of blood glucose which can also lead to the so-called diabetic vascular complications (DVCs), responsible for most of the morbidity, hospitalizations and death registered in these patients. Currently, different approaches to prevent or reduce DM and its DVCs have focused on reducing blood sugar levels, cholesterol management or even changes in lifestyle habits. However, even the strictest glycaemic control strategies are not always sufficient to prevent the development of DVCs, which reflects the need to identify reliable biomarkers capable of predicting further vascular complications in diabetic patients. Endothelial progenitor cells (EPCs), widely known for their potential applications in cell therapy due to their regenerative properties, may be used as differential markers in DVCs, considering that the number and functionality of these cells are affected under the pathological environments related to DM. Besides, drugs commonly used with DM patients may influence the level or behaviour of EPCs as a pleiotropic effect that could finally be decisive in the prognosis of the disease. In the current review, we have analysed the relationship between diabetes and DVCs, focusing on the potential use of EPCs as biomarkers of diabetes progression towards the development of major vascular complications. Moreover, the effects of different drugs on the number and function of EPCs have been also addressed.

Teneligliptin, a DPP-4 Inhibitor, Improves Vascular Endothelial Function via Divergent Actions Including Changes in Circulating Endothelial Progenitor Cells

PURPOSE

Dipeptidyl peptidase-4 (DPP-4) inhibitors increase endothelial progenitor cells (EPCs) in peripheral blood circulation. However, the underlying mechanisms and effects on vascular endothelial function remain unclear. We evaluated whether the DPP-4 inhibitor teneligliptin increases circulating EPCs by inhibiting stromal-derived factor-1α (SDF-1α) and improves flow-mediated vascular dilatation (FMD) in type 2 diabetes mellitus patients with acute coronary syndrome (ACS) or its risk factors.

PATIENTS AND METHODS

This single-center, open-label, prospective, randomized controlled trial evaluated 17 patients (hemoglobin A1c ≤7.5% and peak creatinine phosphokinase <2000 IU/mL) with ACS or a history of ACS or multiple cardiovascular risk factors. Metabolic variables of glucose and lipids, circulating EPCs, plasma DPP-4 activity, and SDF-1α levels, and FMD were evaluated at baseline and 28 ± 4 weeks after enrollment. Patients were randomly assigned to either the teneligliptin (n = 8) or control (n = 9) groups.

RESULTS

The DPP-4 activity (∆-509.5 ± 105.7 vs ∆32.8 ± 53.4 μU/mL) and SDF-1α levels (∆-695.6 ± 443.2 vs ∆11.1 ± 193.7 pg/mL) were significantly decreased after 28 weeks in the teneligliptin group than those in the control group. The number of EPCs showed an increasing trend in the teneligliptin treated group; albeit this did not reach statistical significance. Glucose and lipid levels were not significantly different between the groups before and after 28 weeks. However, FMD was significantly improved in the teneligliptin group when compared to the control group (∆3.8% ± 2.1% vs ∆-0.3% ± 2.9%, P=0.006).

CONCLUSION

Teneligliptin improved FMD through a mechanism other than increasing the number of circulating EPCs.

The impact of vildagliptin on the daily glucose profile and coronary plaque stability in impaired glucose tolerance patients with coronary artery disease: VOGUE-A multicenter randomized controlled trial

Background

The impact of reduction in glycemic excursion on coronary plaques remains unknown. This study aimed to elucidate whether a dipeptidyl peptidase 4 inhibitor could reduce the glycemic excursion and stabilize the coronary plaques compared with conventional management in coronary artery disease (CAD) patients with impaired glucose tolerance (IGT).

Methods

This was a multicenter, randomized controlled trial including CAD patients with IGT under lipid-lowering therapy receiving either vildagliptin (50 mg once a day) or no medication (control group) regarding glycemic treatment. The primary endpoint was changes in the minimum fibrous cap thickness and lipid arc in non-significant native coronary plaques detected by optical coherence tomography at 6 months after intervention. Glycemic variability expressed as the mean amplitude of glycemic excursion (MAGE) measured with a continuous glucose monitoring system was evaluated before and 6 months after intervention.

Results

A total of 20 participants with 47 lesions were allocated to either the vildagliptin group (10 participants, 22 lesions) or the control group (10 participants, 25 lesions). The adjusted difference of mean changes between the groups was − 18.8 mg/dl (95% confidence interval, − 30.8 to − 6.8) (p = 0.0064) for the MAGE (vildagliptin, − 20.1 ± 18.0 mg/dl vs. control, 2.6 ± 12.7 mg/dl), − 22.8° (− 40.6° to − 5.1°) (p = 0.0012) for the mean lipid arc (vildagliptin, − 9.0° ± 25.5° vs. control, 15.8° ± 16.8°), and 42.7 μm (15.3 to 70.1 μm) (p = 0.0022) for the minimum fibrous cap thickness (vildagliptin, 35.7 ± 50.8 μm vs. control, − 15.1 ± 25.2 μm).

Conclusions

Vildagliptin could reduce the MAGE at 6 months and may be associated with the decreased lipid arc and increased minimum FCT of the coronary plaques in CAD patients with IGT as compared with the control group. These findings may represent its potential stabilization effect on coronary plaques, which are characteristic in this patient subset.

Trial registration Registered in the UMIN clinical trial registry (UMIN000008620), Name of the registry: VOGUE trial, Date of registration: Aug 6, 2012, URL: https://upload.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000010058

External Counterpulsation Attenuates Hypertensive Vascular Injury Through Enhancing the Function of Endothelial Progenitor Cells

Background

Vascular injury is a landmark of hypertension and enhanced external counterpulsation (EECP) has been identified as a noninvasive treatment to restore the capacity of endothelial cells. However, the effect of EECP on blood pressure lowering in hypertension and the potential mechanism remain unknown.

Methods

We measured the ambulatory blood pressure (AMBP) and flow-mediated endothelial dilation (FMD) in the essential hypertensive patients who were randomly assigned to the EECP group (n = 20) or control group (n = 20). We also evaluated in vitro function of endothelial progenitor cells (EPCs). Furthermore, multivariate analysis was performed to determine the actual correlation between EPC function and FMD.

Results

Compared with the control, EECP group exhibited decreased systolic [(133.2 ± 4.9) mmHg vs. (139.3 ± 6.4) mmHg, P < 0.05] and diastolic [(83.4 ± 4.5) mmHg vs. (89.5 ± 7.6) mmHg, P < 0.05] blood pressure and increased FMD value [(8.87 ± 2.46%) vs. (7.51 ± 2.32%), P < 0.01]. In addition, the migration [(47.3 ± 6.4)/hpf vs. (33.4 ± 5.1) hpf, P < 0.05] and adhesion [(45.1 ± 5.5)/hpf vs. (28.4 ± 3.9) hpf, P < 0.05] functions of EPCs in the EECP group were improved significantly, whereas no change was observed in the control. Both migration [odds ratio (OR) = 0.47, 95% confidence interval (CI) = 0.27–0.64, P < 0.05] and adhesion (OR = 0.44, 95% CI = −0.0034 to 0.0012, P < 0.05) of EPCs correlated with FMD. After multivariate analysis, the migration (β = 3.37, 95% CI = 1.67–5.33, P < 0.05) and adhesion (β = 3.98, 95% CI = 1.12–6.43, P < 0.05) functions still independently correlated to FMD.

Conclusion

The present study demonstrates for the first time that EECP decreases both systolic and diastolic blood pressure and increases FMD value in hypertension. The fall in endogenous EPCs repair capacity might be an important mechanism of hypertensive vascular injury and could be restored by EECP.

Roles and Mechanisms of Dipeptidyl Peptidase 4 Inhibitors in Vascular Aging

Vascular aging is characterized by alterations in the constitutive properties and biological functions of the blood vessel wall. Endothelial cells (ECs) and vascular smooth muscle cells (VSMCs) are indispensability elements in the inner layer and the medial layer of the blood vessel wall, respectively. Dipeptidyl peptidase-4 (DPP4) inhibitors, as a hypoglycemic agent, play a protective role in reversing vascular aging regardless of their effects in meliorating glycemic control in humans and animal models of type 2 diabetes mellitus (T2DM) through complex cellular mechanisms, including improving EC dysfunction, promoting EC proliferation and migration, alleviating EC senescence, obstructing EC apoptosis, suppressing the proliferation and migration of VSMCs, increasing circulating endothelial progenitor cell (EPC) levels, and preventing the infiltration of mononuclear macrophages. All of these showed that DPP4 inhibitors may exert a positive effect against vascular aging, thereby preventing vascular aging-related diseases. In the current review, we will summarize the cellular mechanism of DPP4 inhibitors regulating vascular aging; moreover, we also intend to compile the roles and the promising therapeutic application of DPP4 inhibitors in vascular aging-related diseases.

Diabetes pharmacotherapy and circulating stem/progenitor cells. State of the art and evidence gaps

Diabetes is burdened with the development of several end-organ complications leading to excess mortality. Though the causes of such organ damage are far from being clarified, diabetes has been redefined as a disease of impaired damage control, wherein ongoing damage is not adequately compensated by activation of repair processes. Bone marrow-derived hematopoietic stem/progenitor cells (HSPCs) and their descendants endothelial progenitor cells (EPCs) have been extensively studied as major players in tissue homeostasis as well as biomarkers of diabetic complication risk. Thus, strategies to raise the levels of circulating HSPCs/EPCs have attracted interest for their potential to modify the future risk of complications. We herein discuss state-of-the-art of the effects exerted by diabetes pharmacotherapy on such cell populations. Further, we highlight which outstanding questions remain to be addressed for a more comprehensive understanding of this topic.

Effects of dipeptidyl peptidase-4 inhibitor linagliptin versus sulphonylurea glimepiride on systemic haemodynamics in overweight patients with type 2 diabetes: A secondary analysis of an 8-week, randomized, controlled, double-blind trial

AIM

To determine the glucose-independent effect of the dipeptidyl peptidase-4 (DPP-4) inhibitor linagliptin versus the sulphonylurea glimepiride on systemic haemodynamics in the fasting and postprandial state in patients with type 2 diabetes (T2D).

MATERIALS AND METHODS

In this prespecified secondary analysis of a phase IV, double-blind trial, 46 metformin-treated, overweight patients with T2D were included and randomly assigned (1:1) to once-daily linagliptin (5 mg) or glimepiride (1 mg) for 8 weeks. In a sub-study involving 26 patients, systemic haemodynamics were also assessed following a standardized liquid meal (Nutridrink Yoghurt style). Systemic haemodynamics (oscillometric device and finger photoplethysmography), arterial stiffness (applanation tonometry) and cardiac sympathovagal balance (heart rate variability [HRV]) were measured in the fasting state and repetitively following the meal. Ewing tests were performed in the fasting state.

RESULTS

From baseline to week 8, linagliptin compared with glimepiride did not affect systemic haemodynamics, arterial stiffness or HRV in the fasting state. Linagliptin increased parasympathetic nervous activity, as measured by the Valsalva manoeuvre (P = .021) and deep breathing test (P = .027) compared with glimepiride. Postprandially, systolic blood pressure (SBP) dropped an average of 7.6 ± 1.6 mmHg. Linagliptin reduced this decrease to 0.7 ± 2.3 mmHg, which was significant to glimepiride (P = .010).

CONCLUSIONS

When compared with glimepiride, linagliptin does not affect fasting blood pressure. However, linagliptin blunted the postprandial drop in SBP, which could benefit patients with postprandial hypotension.

When Good Guys Turn Bad: Bone Marrow's and Hematopoietic Stem Cells' Role in the Pathobiology of Diabetic Complications

Diabetes strongly contributes to the development of cardiovascular disease, the leading cause of mortality and morbidity in these patients. It is widely accepted that hyperglycemia impairs hematopoietic stem/progenitor cell (HSPC) mobilization from the bone marrow (BM) by inducing stem cell niche dysfunction. Moreover, a recent study demonstrated that type 2 diabetic patients are characterized by significant depletion of circulating provascular progenitor cells and increased frequency of inflammatory cells. This unbalance, potentially responsible for the reduction of intrinsic vascular homeostatic capacity and for the establishment of a low-grade inflammatory status, suggests that bone BM-derived HSPCs are not only victims but also active perpetrators in diabetic complications. In this review, we will discuss the most recent literature on the molecular mechanisms underpinning hyperglycemia-mediated BM dysfunction and differentiation abnormality of HSPCs. Moreover, a section will be dedicated to the new glucose-lowering therapies that by specifically targeting the culprits may prevent or treat diabetic complications.

Pharmacological management of vascular endothelial dysfunction in diabetes: TCM and western medicine compared based on biomarkers and biochemical parameters

Diabetes, a worldwide health concern while burdening significant populace of countries with time due to a hefty increase in both incidence and prevalence rates. Hyperglycemia has been buttressed both in clinical and experimental studies to modulate widespread molecular actions that effect macro and microvascular dysfunctions. Endothelial dysfunction, activation, inflammation, and endothelial barrier leakage are key factors contributing to vascular complications in diabetes, plus the development of diabetes-induced cardiovascular diseases. The recent increase in molecular, transcriptional, and clinical studies has brought a new scope to the understanding of molecular mechanisms and the therapeutic targets for endothelial dysfunction in diabetes. In this review, an attempt made to discuss up to date critical and emerging molecular signaling pathways involved in the pathophysiology of endothelial dysfunction and viable pharmacological management targets. Importantly, we exploit some Traditional Chinese Medicines (TCM)/TCM isolated bioactive compounds modulating effects on endothelial dysfunction in diabetes. Finally, clinical studies data on biomarkers and biochemical parameters involved in the assessment of the efficacy of treatment in vascular endothelial dysfunction in diabetes was compared between clinically used western hypoglycemic drugs and TCM formulas.

Endothelium as a Therapeutic Target in Diabetes Mellitus: From Basic Mechanisms to Clinical Practice

Endothelium plays an essential role in human homeostasis by regulating arterial blood pressure, distributing nutrients and hormones as well as providing a smooth surface that modulates coagulation, fibrinolysis and inflammation. Endothelial dysfunction is present in Diabetes Mellitus (DM) and contributes to the development and progression of macrovascular disease, while it is also associated with most of the microvascular complications such as diabetic retinopathy, nephropathy and neuropathy. Hyperglycemia, insulin resistance, hyperinsulinemia and dyslipidemia are the main factors involved in the pathogenesis of endothelial dysfunction. Regarding antidiabetic medication, metformin, gliclazide, pioglitazone, exenatide and dapagliflozin exert a beneficial effect on Endothelial Function (EF); glimepiride and glibenclamide, dipeptidyl peptidase-4 inhibitors and liraglutide have a neutral effect, while studies examining the effect of insulin analogues, empagliflozin and canagliflozin on EF are limited. In terms of lipid-lowering medication, statins improve EF in subjects with DM, while data from short-term trials suggest that fenofibrate improves EF; ezetimibe also improves EF but further studies are required in people with DM. The effect of acetylsalicylic acid on EF is dose-dependent and lower doses improve EF while higher ones do not. Clopidogrel improves EF, but more studies in subjects with DM are required. Furthermore, angiotensin- converting-enzyme inhibitors /angiotensin II receptor blockers improve EF. Phosphodiesterase type 5 inhibitors improve EF locally in the corpus cavernosum. Finally, cilostazol exerts favorable effect on EF, nevertheless, more data in people with DM are required.

Glucagon-like Peptide 1 Receptor Agonists, Diabetic Retinopathy and Angiogenesis: The AngioSafe Type 2 Diabetes Study

AIMS

Recent trials provide conflicting results on the association between glucagon-like peptide 1 receptor agonists (GLP-1RA) and diabetic retinopathy (DR). The aim of the AngioSafe type 2 diabetes (T2D) study was to determine the role of GLP-1RA in angiogenesis using clinical and preclinical models.

METHODS

We performed two studies in humans. In study 1, we investigated the effect of GLP-1RA exposure from T2D diagnosis on the severity of DR, as diagnosed with retinal imaging (fundus photography). In study 2, a randomized 4-week trial, we assessed the effect of liraglutide on circulating hematopoietic progenitor cells (HPCs), and angio-miRNAs.We then studied the experimental effect of Exendin-4, on key steps of angiogenesis: in vitro on human endothelial cell proliferation, survival and three-dimensional vascular morphogenesis; and in vivo on ischemia-induced neovascularization of the retina in mice.

RESULTS

In the cohort of 3154 T2D patients, 10% displayed severe DR. In multivariate analysis, sex, disease duration, glycated hemoglobin (HbA1c), micro- and macroangiopathy, insulin therapy and hypertension remained strongly associated with severe DR, while no association was found with GLP-1RA exposure (o 1.139 [0.800-1.622], P = .47). We further showed no effect of liraglutide on HPCs, and angio-miRNAs. In vitro, we demonstrated that exendin-4 had no effect on proliferation and survival of human endothelial cells, no effect on total length and number of capillaries. Finally, in vivo, we showed that exendin-4 did not exert any negative effect on retinal neovascularization.

CONCLUSIONS

The AngioSafe T2D studies provide experimental and clinical data confirming no effect of GLP-1RA on angiogenesis and no association between GLP-1 exposure and severe DR.

Vasculoprotective Effects of Vildagliptin. Focus on Atherogenesis

Vildagliptin is a representative of Dipeptidyl Peptidase-4 (DPP-4) inhibitors, antihyperglycemic drugs, approved for use as monotherapy and combination therapy in type 2 diabetes mellitus. By inhibiting enzymatic decomposition, DPP-4 inhibitors increase the half-life of incretins such as GLP-1 (Glucagon-like peptide-1) and GIP (Gastric inhibitors polypeptide) and prolong their action. Some studies present results suggesting the anti-sclerotic and vasculoprotective effects of vildagliptin reaching beyond glycemic control. Vildagliptin is able to limit inflammation by suppression of the NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) signaling pathway and proinflammatory agents such as TNF-α (tumor necrosis factor α), IL-1β (Interleukin-1β), and IL-8 (Interleukin 8). Moreover, vildagliptin regulates lipid metabolism; attenuates postprandial hypertriglyceridemia; and lowers serum triglycerides, apolipoprotein B, and blood total cholesterol levels. This DPP-4 inhibitor also reduces macrophage foam cell formation, which plays a key role in atheromatous plaque formation and stability. Vildagliptin reduces vascular stiffness via elevation of nitric oxide synthesis, improves vascular relaxation, and results in reduction in both systolic and diastolic blood pressure. Treatment with vildagliptin lowers the level of PAI-1 presenting possible antithrombotic effect. By affecting the endothelium, inflammation, and lipid metabolism, vildagliptin may affect the development of atherosclerosis at its various stages. The article presents a summary of the studies assessing vasculoprotective effects of vildagliptin with special emphasis on atherogenesis.

Activation of Transient Receptor Potential Channel Vanilloid 4 by DPP-4 (Dipeptidyl Peptidase-4) Inhibitor Vildagliptin Protects Against Diabetic Endothelial Dysfunction

Endothelial dysfunction is an early step to the progression of cardiovascular diseases in diabetes. Apart from their anti-diabetic action, DPP-4 (dipeptidyl peptidase-4) inhibitors also reduce cardiovascular events in diabetic patients. However, the underlying mechanism of the beneficial effect of DPP-4 inhibitor on endothelial function is still obscure. In this study, we intervened type 1 or 2 diabetic model mice with vildagliptin for 4 weeks and measured the vascular reactivity. We found that vildagliptin improved endothelium-dependent vasodilation in diabetic mice independent of GLP-1 (glucagonlike peptide-1), but this effect was blocked by a SIRT1 (Sirtuin 1) inhibitor, Ex527. Mechanistically, vildagliptin-activated Transient Receptor Potential Channel Vanilloid 4 (TRPV4) to promote extracellular calcium uptake in endothelial cells, which activated AMPK (AMP-activated protein kinase)/SIRT1 pathway to counteract hyperglycemia-induced endothelial reactive oxygen species generation and senescence. Vildagliptin directly binds to TRPV4 by forming a hydrogen bond, which is critical to vildagliptin-evoked endothelial calcium intake. Knockout or inhibition of TRPV4 erased the beneficial role of vildagliptin. In addition, activation of SIRT1 by SRT1720 improved endothelial function independent of TRPV4 and reduced TRPV4 transcription to maintain an appropriate calcium level. In summary, our findings prove that vildagliptin protects against hyperglycemia-induced endothelial dysfunction by activating TRPV4-meditaed Ca²⁺ uptake, which helps to re-understand the mechanism of DPP-4 inhibitors and expand the therapeutic scope.

Vildagliptin inhibits high free fatty acid (FFA)-induced NLRP3 inflammasome activation in endothelial cells

Elevated free fatty acids (FFAs) are a risk factor for type 2 diabetes. Endothelial dysfunction induced by high levels of FFAs is one of the mechanisms related to the progression of diabetes. In clinical diabetes care, DPP-4 inhibitors have been shown to be effective in reducing glucose levels. In this study, we investigated the molecular mechanism of the clinically available DPP-4 inhibitor vildagliptin in the protection of FFA-induced endothelial dysfunction. Treatment of endothelial cells with vildagliptin inhibits FFA-induced cellular LDH release and generation of ROS. Vildagliptin also reverses FFA-induced reduced levels of GSH and elevated expression of the FFA-associated NAPHD oxidase protein NOX-4. Moreover, vildagliptin ameliorates the reduction in mitochondrial potential triggered by FFAs. Mechanistically, we show that vildagliptin suppresses FFA-induced expression of proteins of the NLRP3 inflammasome complex, including NLRP3, ASC, p20 and HMGB-1, and mitigates FFA-induced inactivation of the AMPK pathway. Consequently, vildagliptin inhibits production of two cytokines that are favored by NLRP3 inflammasome machinery: IL-1β and IL-18. Finally, we demonstrate that vildagliptin ameliorates FFA-induced reduced eNOS, indicating its protective role against endothelial dysfunction. Collectively, we conclude that the protective role of vildagliptin in endothelial cells is mediated via suppression of the AMPK-NLRP3 inflammasome-HMGB-1 axis pathway. These findings imply that the anti-diabetic drug vildagliptin possesses dual therapeutic applications in lowering glucose and improving vascular function.

Metformin and second- or third-generation sulphonylurea combination therapy for adults with type 2 diabetes mellitus

BACKGROUND

The number of people with type 2 diabetes mellitus (T2DM) is increasing worldwide. The combination of metformin and sulphonylurea (M+S) is a widely used treatment. Whether M+S shows better or worse effects in comparison with other antidiabetic medications for people with T2DM is still controversial.

OBJECTIVES

To assess the effects of metformin and sulphonylurea (second- or third-generation) combination therapy for adults with type 2 diabetes mellitus.

SEARCH METHODS

We updated the search of a recent systematic review from the Agency for Healthcare Research and Quality (AHRQ). The updated search included CENTRAL, MEDLINE, Embase, ClinicalTrials.gov and WHO ICTRP. The date of the last search was March 2018. We searched manufacturers' websites and reference lists of included trials, systematic reviews, meta-analyses and health technology assessment reports. We asked investigators of the included trials for information about additional trials.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) randomising participants 18 years old or more with T2DM to M+S compared with metformin plus another glucose-lowering intervention or metformin monotherapy with a treatment duration of 52 weeks or more.

DATA COLLECTION AND ANALYSIS

Two review authors read all abstracts and full-text articles and records, assessed risk of bias and extracted outcome data independently. We used a random-effects model to perform meta-analysis, and calculated risk ratios (RRs) for dichotomous outcomes and mean differences (MDs) for continuous outcomes, using 95% confidence intervals (CIs) for effect estimates. We assessed the certainty of the evidence using the GRADE instrument.

MAIN RESULTS

We included 32 RCTs randomising 28,746 people. Treatment duration ranged between one to four years. We judged none of these trials as low risk of bias for all 'Risk of bias' domains. Most important events per person were all-cause and cardiovascular mortality, serious adverse events (SAE), non-fatal stroke (NFS), non-fatal myocardial infarction (MI) and microvascular complications. Most important comparisons were as follows:Five trials compared M+S (N = 1194) with metformin plus a glucagon-like peptide 1 analogue (N = 1675): all-cause mortality was 11/1057 (1%) versus 11/1537 (0.7%), risk ratio (RR) 1.15 (95% confidence interval (CI) 0.49 to 2.67); 3 trials; 2594 participants; low-certainty evidence; cardiovascular mortality 1/307 (0.3%) versus 1/302 (0.3%), low-certainty evidence; serious adverse events (SAE) 128/1057 (12.1%) versus 194/1537 (12.6%), RR 0.90 (95% CI 0.73 to 1.11); 3 trials; 2594 participants; very low-certainty evidence; non-fatal myocardial infarction (MI) 2/549 (0.4%) versus 6/1026 (0.6%), RR 0.57 (95% CI 0.12 to 2.82); 2 trials; 1575 participants; very low-certainty evidence.Nine trials compared M+S (N = 5414) with metformin plus a dipeptidyl-peptidase 4 inhibitor (N = 6346): all-cause mortality was 33/5387 (0.6%) versus 26/6307 (0.4%), RR 1.32 (95% CI 0.76 to 2.28); 9 trials; 11,694 participants; low-certainty evidence; cardiovascular mortality 11/2989 (0.4%) versus 9/3885 (0.2%), RR 1.54 (95% CI 0.63 to 3.79); 6 trials; 6874 participants; low-certainty evidence; SAE 735/5387 (13.6%) versus 779/6307 (12.4%), RR 1.07 (95% CI 0.97 to 1.18); 9 trials; 11,694 participants; very low-certainty evidence; NFS 14/2098 (0.7%) versus 8/2995 (0.3%), RR 2.21 (95% CI 0.74 to 6.58); 4 trials; 5093 participants; very low-certainty evidence; non-fatal MI 15/2989 (0.5%) versus 13/3885 (0.3%), RR 1.45 (95% CI 0.69 to 3.07); 6 trials; 6874 participants; very low-certainty evidence; one trial in 64 participants reported no microvascular complications were observed (very low-certainty evidence).Eleven trials compared M+S (N = 3626) with metformin plus a thiazolidinedione (N = 3685): all-cause mortality was 123/3300 (3.7%) versus 114/3354 (3.4%), RR 1.09 (95% CI 0.85 to 1.40); 6 trials; 6654 participants; low-certainty evidence; cardiovascular mortality 37/2946 (1.3%) versus 41/2994 (1.4%), RR 0.78 (95% CI 0.36 to 1.67); 4 trials; 5940 participants; low-certainty evidence; SAE 666/3300 (20.2%) versus 671/3354 (20%), RR 1.01 (95% CI 0.93 to 1.11); 6 trials; 6654 participants; very low-certainty evidence; NFS 20/1540 (1.3%) versus 16/1583 (1%), RR 1.29 (95% CI 0.67 to 2.47); P = 0.45; 2 trials; 3123 participants; very low-certainty evidence; non-fatal MI 25/1841 (1.4%) versus 21/1877 (1.1%), RR 1.21 (95% CI 0.68 to 2.14); P = 0.51; 3 trials; 3718 participants; very low-certainty evidence; three trials (3123 participants) reported no microvascular complications (very low-certainty evidence).Three trials compared M+S (N = 462) with metformin plus a glinide (N = 476): one person died in each intervention group (3 trials; 874 participants; low-certainty evidence); no cardiovascular mortality (2 trials; 446 participants; low-certainty evidence); SAE 34/424 (8%) versus 27/450 (6%), RR 1.68 (95% CI 0.54 to 5.21); P = 0.37; 3 trials; 874 participants; low-certainty evidence; no NFS (1 trial; 233 participants; very low-certainty evidence); non-fatal MI 2/215 (0.9%) participants in the M+S group; 2 trials; 446 participants; low-certainty evidence; no microvascular complications (1 trial; 233 participants; low-certainty evidence).Four trials compared M+S (N = 2109) with metformin plus a sodium-glucose co-transporter 2 inhibitor (N = 3032): all-cause mortality was 13/2107 (0.6%) versus 19/3027 (0.6%), RR 0.96 (95% CI 0.44 to 2.09); 4 trials; 5134 participants; very low-certainty evidence; cardiovascular mortality 4/1327 (0.3%) versus 6/2262 (0.3%), RR 1.22 (95% CI 0.33 to 4.41); 3 trials; 3589 participants; very low-certainty evidence; SAE 315/2107 (15.5%) versus 375/3027 (12.4%), RR 1.02 (95% CI 0.76 to 1.37); 4 trials; 5134 participants; very low-certainty evidence; NFS 3/919 (0.3%) versus 7/1856 (0.4%), RR 0.87 (95% CI 0.22 to 3.34); 2 trials; 2775 participants; very low-certainty evidence; non-fatal MI 7/890 (0.8%) versus 8/1374 (0.6%), RR 1.43 (95% CI 0.49 to 4.18; 2 trials); 2264 participants; very low-certainty evidence; amputation of lower extremity 1/437 (0.2%) versus 1/888 (0.1%); very low-certainty evidence.Trials reported more hypoglycaemic episodes with M+S combination compared to all other metformin-antidiabetic agent combinations. Results for M+S versus metformin monotherapy were inconclusive. There were no RCTs comparing M+S with metformin plus insulin. We identified nine ongoing trials and two trials are awaiting assessment. Together these trials will include approximately 16,631 participants.

AUTHORS' CONCLUSIONS

There is inconclusive evidence whether M+S combination therapy compared with metformin plus another glucose-lowering intervention results in benefit or harm for most patient-important outcomes (mortality, SAEs, macrovascular and microvascular complications) with the exception of hypoglycaemia (more harm for M+S combination). No RCT reported on health-related quality of life.

Vildagliptine protects SH-SY5Y human neuron-like cells from Aβ 1-42 induced toxicity, in vitro

The amyloid β (Aβ) toxic fibrils is thought to play a central role in the onset and progression of Alzheimer's disease (AD) because of it is a main formation of senile plaques. Diabetic patients are more vulnerable to caught Alzheimer's disease. Vildagliptine, a novel anti diabetic agent, has been reported to exert protective effects on AD rat models in restricted study. We aimed to investigate any protective effects of vildagliptine against Aβ fibrils on SH-SY5Y cell line. Vildagliptine decreased PSEN1 and PSEN2 mRNA levels which enroll Aβ production. In addition, vildagliptin was downregulated caspase-3 and caspase-9 expression levels which were evoked by Aβ. Also we confirmed cellular viability with real time cell analyzer and MTT assay. Our data exposed that vildagliptine has lowering effect on GSK3β and Tau phosphorylation. However we did not get protective effect of vildagliptine against Aβ toxicity on mitochondrial membrane potential. These results indicate that vildagliptine exerts a protective effect against Aβ by decreasing apoptosis related proteins, lowering GSK3β and Tau phosphorylation levels in addition to expression of PSEN1 and PSEN2 mRNA downregulation effect.

A safety and tolerability profile comparison between dipeptidyl peptidase-4 inhibitors and sulfonylureas in diabetic patients: A systematic review and meta-analysis

BACKGROUND

The first treatment approach for type 2 diabetes mellitus is lifestyle change and metformin, but it is usually not sufficient. For some time, the anti-hyperglycemic classes of sulfonylureas and dipeptidyl peptidase-4 (DPP-4) inhibitors were considered second-line of treatment, since they show similar efficacy effect. However, the recent ADA-EASD consensus gives the preference to DPP-4 inhibitors compared to sulfonylureas, except if cost is a major problem. We performed a meta-analysis for safety and tolerability profile to comprehend which treatment has less adverse events.

METHODS

PUBMED and EMBASE databases were searched from inception until July 2017 to retrieve RCT studies comparing DPP-4 inhibitors and sulfonylureas treatments in adult type 2 diabetes patients. There was no language restriction. We extracted and combined data from studies comparison that reported safety profile and weight change. A random effect, meta-analytic model was applied to all calculations. Cochrane collaboration tool was used to assess quality and bias of the included studies. Trial registered with PROSPERO (CRD42017075823).

FINDINGS

Out of 1472 articles identified in our search and screened for eligibility, 36 studies comparing DPP-4 inhibitors and sulfonylureas were identified. DPP-4 inhibitors in combination with metformin had less overall adverse events (RR: 0·90; 95% CI, 0·86-0·94; p < 0·0001; I² = 83%; 17 studies), cardiovascular events (RR: 0·54; 95% CI, 0·37-0·79; p = 0·002; I² = 0%; 6 studies), hypoglycemia (RR: 0·17; 95% CI, 0·13-0·22; p < 0·00001; I² = 76%; 17 studies) and severe hypoglycemic events (RR: 0·10; 95% CI, 0·05-0·19; p < 0·00001; I² = 0%; 12 studies). The mean difference of the weight change was 1·92 kg in favor of DPP-4 inhibitors in combination with metformin in relation to sulfonylureas in combination with metformin. Monotherapy with DPP-4 inhibitors also had less rates of hypoglycemia (RR: 0·31; 95% CI, 0·24-0·41; p < 0·00001; I² = 0%; 8 studies) and severe hypoglycemic events (RR: 0·26; 95% CI, 0·10-0·66; p = 0·004; I² = 0%; 8 studies) and patients did not gain 1·19 kg.

INTERPRETATION

These results suggest better safety profile for DPP-4 inhibitors than sulfonylureas for both comparisons, and it is more notable when the treatment regimen includes metformin.

FUNDING

This study was funded by Takeda Pharmaceuticals, Brazil.

Potential role of Peroxisome Proliferator Activated Receptor gamma analogues in regulation of endothelial progenitor cells in diabetes mellitus: An overview

Endothelial progenitor cells are recognized as the potential targets for the revascularization and angiogenesis because of their ability to get themselves transformed into mature endothelial cells. Underlying pathophysiology in diabetes mellitus leads to decrease in circulatory endothelial progenitor cells, resulting in diabetic macro-vascular and micro-vascular complications. Peroxisome Proliferator Activated Receptor (PPAR) gamma analogues serves as an effective therapy for controlling blood sugar levels and preventing its complications. Reports of clinical trials and meta-analysis of clinical trial suggests the beneficial aspects of PPAR gamma therapy in increasing the number and function of circulating endothelial progenitor cells. This review highlights the pleotropic effect of PPAR gamma analogs, apart from their antidiabetic action via reduction of oxidative stress, increasing expression of eNOS, reducing level of miR 22, miR 222 levels and positive modulation of rapamycin/Protein kinase B/phosphoinoside3-kinase pathways, preventing the early apoptosis, enhanced mobility proliferation and transformation into mature endothelial cells. PPAR gamma therapy in diabetes regulates endothelial progenitor cells, reduces complications of diabetes like retinopathy, nephropathy, neuropathy, cardiomyopathy, deep vein thrombosis, and maintains the healthy vasculature.

Combined low-dose testosterone and vildagliptin confers cardioprotection in castrated obese rats

Although a physiological dose of testosterone replacement therapy (p-TRT) has been shown to improve left ventricular (LV) function, some studies reported that it increased the risk of myocardial infarction in testosterone-deprived men. We previously reported that vildagliptin might be used as an alternative to the p-TRT. In this study, we hypothesized that a combined low-dose TRT with vildagliptin exerts greater efficacy than single regimen in improving cardiometabolic function in obese-insulin resistant rats with testosterone deprivation. Male rats were fed on a normal diet or high-fat diet for 12 weeks. Then, they were divided into 2 subgroups; sham operation and orchiectomy (NDO, HFO) and fed their diets for another 12 weeks. At week 25, orchiectomized rats were subdivided into 4 groups, vehicle, p-TRT, vildagliptin, and combined drugs. At week 29, cardiometabolic and biochemical parameters were determined. HFO rats had obese-insulin resistance with a worse LV dysfunction, compared with sham. Vildagliptin and combined drugs effectively reduced insulin resistance. All treatments reduced blood pressure, cardiac autonomic imbalance, LV dysfunction, mitochondrial dysfunction, apoptosis, and increased mitochondrial fusion in NDO and HFO rats. However, p-TRT and combined drugs, but not vildagliptin, reduced mitochondrial fission in NDO and HFO rats. We concluded that combined low-dose TRT with vildagliptin mitigated LV function at a similar level to the p-TRT alone and vildagliptin via improving mitochondrial fusion, reducing mitochondrial dysfunction and apoptosis in testosterone-deprived rats. Our findings suggest that low-dose TRT combined with vildagliptin may be an alternative for p-TRT in conditions of obese-insulin resistance with testosterone deprivation.

Effects of SGLT2 Inhibitors on Circulating Stem and Progenitor Cells in Patients With Type 2 Diabetes

CONTEXT

Reduction in the levels of circulating stem cells (CSCs) and endothelial progenitor cells (EPCs) predicts development or progression of microangiopathy and macroangiopathy in patients with type 2 diabetes (T2D).

OBJECTIVE

We tested whether treatment with sodium glucose cotransporter-2 (SGLT2) inhibitors affected the levels of CSCs and EPCs.

DESIGN

A randomized trial of dapagliflozin vs placebo with open-label extension, and an open-label observational study of empagliflozin treatment.

SETTING

Tertiary referral diabetes outpatient clinic.

PATIENTS

Patients with T2D aged 18 to 75 years.

INTERVENTION

Dapagliflozin at 10 mg vs placebo (n = 31); empagliflozin at 10 mg (n = 15).

MAIN OUTCOME MEASURES

We measured CSCs (CD34+) and EPCs (CD34+KDR+) by flow cytometry at baseline, at 12 weeks, and after the extension period.

RESULTS

After 12 weeks, CSCs declined nonsignificantly in the dapagliflozin group, remained stable in the placebo group, and the change from baseline was not significantly different between the two groups. EPCs declined nonsignificantly in the dapagliflozin group, increased nonsignificantly in the placebo group, and the change from baseline was significantly different between the two groups. After an open-label extension period of about 1.5 years, CSCs remained stable over time, whereas EPCs significantly increased in patients who received dapagliflozin. In all patients, irrespectively of treatment, EPCs increased significantly from baseline to the end of observation, concomitantly with improvement in HbA1c. In a cohort of 15 patients who received open-label empagliflozin for 12 weeks, CSCs declined nonsignificantly, whereas EPCs remained stable.

CONCLUSION

SGLT2 inhibitors do not significantly increase CSCs or EPCs. Thus, cardiovascular protection by SGLT2 inhibitors may not directly involve stem/progenitor cells.

Impact of dipeptidyl-peptidase 4 inhibitors on cardiovascular diseases

Dipeptidyl peptidase 4 (DPP-4) inhibitor is a novel group of medicine employed in type 2 diabetes mellitus (T2DM),which improves meal stimulated insulin secretion by protecting glucagon-like peptide-1 (GLP-1) and glucose dependent insulinotropic polypeptide (GIP) from enzymatic degradation. Cardiovascular diseases are serious complications and leading causes of mortality among individuals with diabetes mellitus. Glycemic control per se seems to fail in preventing the progression of diabetic cardiovascular complications. DPP-4 has the capability to inactivate not only incretins, but also a series of cytokines, chemokines, and neuropeptides involved in inflammation, immunity, and vascular function. Pre-clinical studies suggested that DPP-4 inhibitors may have potential cardiovascular protective effects in addition to their antidiabetic actions. In recent years, a number of clinical trials have been conducted to evaluate the effect of different DPP-4 inhibitors on the cardiovascular system. We herein review the available clinical studies in cardiovascular effects played by each DPP-4 inhibitor and discuss the prospective application of DPP-4 inhibitors on cardiovascular diseases.

Have dipeptidyl peptidase-4 inhibitors ameliorated the vascular complications of type 2 diabetes in large-scale trials? The potential confounding effect of stem-cell chemokines

Drugs that inhibit dipeptidyl peptidase-4 (DPP-4) are conventionally regarded as incretin-based agents that signal through the glucagon-like peptide-1 (GLP-1) receptor. However, inhibition of DPP-4 also potentiates the stem cell chemokine, stromal cell-derived factor-1 (SDF-1), which can promote inflammation, proliferative responses and neovascularization. In large-scale cardiovascular outcome trials, enhanced GLP-1 signaling has reduced the risk of atherosclerotic ischemic events, potentially because GLP-1 retards the growth and increases the stability of atherosclerotic plaques. However, DPP-4 inhibitors have not reduced the risk of major adverse cardiovascular events, possibly because potentiation of SDF-1 enhances plaque growth and instability, activates deleterious neurohormonal mechanisms, and promotes cardiac inflammation and fibrosis. Similarly, trials with GLP-1 agonists and sodium-glucose cotransporter 2 inhibitors have reported favorable effects on renal function, even after only 3-4 years of treatment. In contrast, no benefits on the rate of decline in glomerular filtration rate have been seen in trials of DPP-4 inhibitors, perhaps because the renal actions of DPP-4 inhibitors are primarily mediated by potentiation of SDF-1, not GLP-1. Experimentally, SDF-1 can promote podocyte injury and glomerulosclerosis. Furthermore, the natriuretic action of SDF-1 occurs primarily in the distal tubules, where it cannot utilize tubuloglomerular feedback to modulate the deleterious effects of glomerular hyperfiltration. Potentiation of SDF-1 in experimental models may also exacerbate both retinopathy and neuropathy. Therefore, although DPP-4 inhibitors have attractive clinical features, the benefits that might be expected from GLP-1 signaling may be undermined by their actions to enhance SDF-1.

Active Stromal Cell-Derived Factor 1α and Endothelial Progenitor Cells are Equally Increased by Alogliptin in Good and Poor Diabetes Control

Background:

It is postulated that the ability of dipeptidyl peptidase-4 inhibitors (DPP-4-i) to increase circulating endothelial progenitor cells (EPCs) may be at least partly mediated by active stromal cell–derived factor 1α (SDF-1α) (a pivotal mediator of stem cell mobilization from the bone marrow). As other DPP-4-i were demonstrated to increase EPC concentrations, in this study, we sought to investigate the ability of the DPP-4-i alogliptin in modifying EPCs and SDF-1α, in patients with good and poor diabetes control.

Methods:

Two groups of diabetic patients on metformin were divided by hemoglobin A_1c (HbA_1c): Group A—those with HbA_1c ≤6.5% (28 patients) and Group B—those with HbA_1c 7.5% to 8.5% (31 patients). Both groups received alogliptin 25 mg/daily for 4 months. At baseline and 4 months later, clinical, laboratory parameters, EPCs, and active SDF-1α were determined.

Results:

After 4-month treatment with alogliptin, either Group A or Group B showed reduced HbA_1c levels and concomitant similar increase in EPCs and active SDF-1α.

Conclusions:

Alogliptin showed significant benefits in increasing EPCs and active SDF-1α either in good or poor diabetes control. The study demonstrated that similar to other DPP-4-i, also alogliptin is able to increase EPC concentrations, suggesting the existence of a class effect mediated by SDF-1α. The extent of increase in EPCs is independent from baseline diabetes control.

Potential humoral mediators of remote ischemic preconditioning in patients undergoing surgical coronary revascularization

Remote ischemic preconditioning (RIPC) by repeated brief cycles of limb ischemia/reperfusion may reduce myocardial ischemia/reperfusion injury and improve patients‘ prognosis after elective coronary artery bypass graft (CABG) surgery. The signal transducer and activator of transcription (STAT)5 activation in left ventricular myocardium is associated with RIPC´s cardioprotection. Cytokines and growth hormones typically activate STATs and could therefore act as humoral transfer factors of RIPC´s cardioprotection. We here determined arterial plasma concentrations of 25 different cytokines, growth hormones, and other factors which have previously been associated with cardioprotection, before (baseline)/after RIPC or placebo (n = 23/23), respectively, and before/after ischemic cardioplegic arrest in CABG patients. RIPC-induced protection was reflected by a 35% reduction of serum troponin I release. With the exception of interleukin-1α, none of the humoral factors changed in their concentrations after RIPC or placebo, respectively. Interleukin-1α, when normalized to baseline, increased after RIPC (280 ± 56%) but not with placebo (97 ± 15%). The interleukin-1α concentration remained increased until after ischemic cardioplegic arrest and was also higher than with placebo in absolute concentrations (25 ± 6 versus 16 ± 3 pg/mL). Only interleukin-1α possibly fulfills the criteria which would be expected from a substance to be released in response to RIPC and to protect the myocardium during ischemic cardioplegic arrest.

Multiple therapeutic effect of endothelial progenitor cell regulated by drugs in diabetes and diabetes related disorder

BACKGROUND

Reduced levels of endothelial progenitor cells (EPCs) counts have been reported in diabetic mellitus (DM) patients and other diabetes-related disorder. EPCs are a circulating, bone marrow-derived cell population that appears to participate in vasculogenesis, angiogenesis and damage repair. These EPC may revert the damage caused in diabetic condition. We aim to identify several existing drugs and signaling molecule, which could alleviate or improve the diabetes condition via mobilizing and increasing EPC number as well as function.

MAIN BODY

Accumulated evidence suggests that dysregulation of EPC phenotype and function may be attributed to several signaling molecules and cytokines in DM patients. Hyperglycemia alone, through the overproduction of reactive oxygen species (ROS) via eNOS and NOX, can induce changes in gene expression and cellular behavior in diabetes. Furthermore, reports suggest that EPC telomere shortening via increased oxidative DNA damage may play an important role in the pathogenesis of coronary artery disease in diabetic patients. In this review, different type of EPC derived from different sources has been discussed along with cell-surface marker. The reduced number and immobilized EPC in diabetic condition have been mobilized for the therapeutic purpose via use of existing, and novel drugs have been discussed. Hence, evidence list of all types of drugs that have been reported to target the same pathway which affect EPC number and function in diabetes has been reviewed. Additionally, we highlight that proteins are critical in diabetes via polymorphism and inhibitor studies. Ultimately, a lucid pictorial explanation of diabetic and normal patient signaling pathways of the collected data have been presented in order to understand the complex signaling mystery underlying in the diseased and normal condition.

CONCLUSION

Finally, we conclude on eNOS-metformin-HSp90 signaling and its remedial effect for controlling the EPC to improve the diabetic condition for delaying diabetes-related complication. Altogether, the review gives a holistic overview about the elaborate therapeutic effect of EPC regulated by novel and existing drugs in diabetes and diabetes-related disorder.

Effects of a New Nutraceutical Formulation (Berberine, Red Yeast Rice and Chitosan) on Non-HDL Cholesterol Levels in Individuals with Dyslipidemia: Results from a Randomized, Double Blind, Placebo-Controlled Study

Increased non high-density lipoprotein (HDL)/low-density lipoprotein (LDL) cholesterol levels are independent risk factors for cardiovascular (CV) mortality with no documented threshold. A new combination of nutraceuticals (berberine 200 mg, monacolin K 3 mg, chitosan 10 mg and coenzyme Q 10 mg) with additive lipid-lowering properties has become available. The aim of the study is to test the efficacy of the nutraceutical formulation (one daily) in lowering non-HDL cholesterol vs. placebo at 12 weeks in individuals with non-HDL-cholesterol levels ≥160 mg/dL. 39 subjects (age 52 ± 11 years; 54% females; body mass index 27 ± 4 kg/m²) were randomized (3:1) in a double blind phase II placebo-controlled study. At baseline, 4 and 12 weeks main clinical/biohumoral parameters, pro-inflammatory cytokines, (gut)-hormones, proprotein convertase subtilisin/kexin type 9 (PCSK9) levels and endothelial progenitor cell (EPC) number were assessed. Baseline characteristics were comparable in the two groups. The intervention significantly decreased non-HDL cholesterol (−30 ± 20 mg/dL; p = 0.012), LDL cholesterol (−31 ± 18 mg/dL, p = 0.011) and apolipoprotein (Apo) B (−14 ± 12 mg/dL, p = 0.030) levels compared to the placebo. Pro-inflammatory, hormonal, PCSK9 and EPC levels remained stable throughout the study in both groups. The intervention was well tolerated. Three adverse events occurred: Epstein Barr virus infection, duodenitis and asymptomatic but significant increase in creatine phosphokinase (following intense physical exercise) which required hospitalization. The tested nutraceutical formulation may represent a possible therapeutic strategy in dyslipidemic individuals in primary prevention.