The synergistic effects of saxagliptin and metformin on CD34+ endothelial progenitor cells in early type 2 diabetes patients: a randomized clinical trial

Exploration of metformin-based drug combination for mitigating diabetes-associated atherosclerotic diseases

Diabetes mellitus is a substantial global health threat due to its high prevalence and its serious complications. The hyperglycemic state causes damage to vascular endothelial cells and disturbance of lipid metabolism, thus contributing to the development of vascular disorders, especially atherosclerotic diseases. Aggressive glycemic control combined with vascular intervention is critical to the prevention and treatment of diabetes-associated atherosclerosis. It is suggested that metformin should be combined with hypoglycemic agents with proven vascular benefits for treating type 2 diabetes (T2DM) complicated with atherosclerotic diseases. Clinical studies indicates that the preferred combination is metformin with either glucagon-like peptide-1 receptor agonist or sodium/glucose cotransporter-2 inhibitor, which could offer additional vascular benefits and reduce the risk of atherosclerotic complications. Likewise, combination therapy with metformin and hypolipidemic agents has also shown additive effects on glucose control and lipid-lowering in patients with both diabetes and dyslipidemia, whereas extensive clinical trials using atherosclerotic-associated outcomes are required to support the vascular benefits. Moreover, co-administration of metformin with systemic antioxidant or anti-inflammatory therapy may also provide additional vascular benefits as indicated by several animal studies. For instance, a recent study found that additional supplementation of cholecalciferol and taurine enhanced metformin efficacy in controlling diabetes while reducing the risk of associated atherosclerotic complications. However, these potential benefits remain need validation by the evidence from clinical studies. Despite the limitations, such as heterogeneity across different patient populations, and deficiency in long-term outcomes, such efforts can contribute to finding optimal drug combinations to improve the management of T2DM and reduce its atherosclerotic complications.

Impact of DPP-4 Inhibitors on Interleukin Levels in Type 2 Diabetes Mellitus

BACKGROUND AND OBJECTIVE

Accumulating evidence had implicated pathological involvement of interleukins (ILs) in progression and complications in patients with type 2 diabetes mellitus (T2DM). Dipeptidyl peptidase-4 inhibitors (DPP-4i) produced favorable effects on glucose homeostasis in T2DM. This study aimed to evaluate the impact of DPP-4i on IL concentrations in T2DM.

DATA SOURCES

PubMed, Embase, and the Cochrane library were systematically searched for relevant articles from inception to May 31, 2024. The search included DPP-4i, T2DM, and randomized controlled trials (RCTs) and related terms.

STUDY SELECTION AND DATA EXTRACTION

Placebo- or active agents-controlled human studies were screened. All the RCTs were identified if they provided detailed information on changes of ILs during DPP-4i treatment.

DATA SYNTHESIS

A total of 14 RCTs involving 850 participants were identified. Pooled estimates revealed that DPP-4i significantly lowered IL-6 concentrations (-0.54 pg/mL; 95% CI, -0.82 to -0.25; I2 = 10%, P = .0003) compared to placebo. Similar effects were demonstrated for IL-1β (-16.33 pg/mL; 95% CI, -19.56 to -13.11; I2 = 0%, P < .00001), whereas the effect on IL-18 was not statistically significant (-13.55 pg/mL; 95% CI, -76.95 to 49.85; I2 = 0%, P = .68). Subgroup analysis on IL-6 demonstrated that marked effects were found in groups of basal IL-6 concentrations (< 5 pg/mL), body mass index (≥ 28 kg/m2) and type of DPP-4i (linagliptin).

CONCLUSION

DPP-4i favorably decreased IL-6 levels in patients with T2DM. The impact of DPP-4i on IL-1β and IL-18 needed to be explored with more studies. Further trials should be performed to elucidate this anti-inflammatory effect of DPP-4i during treatment of T2DM.

Metformin: Its salutary effects beyond diabetes mellitus

Metformin, an oral hypoglycemic agent, is commonly used in patients with type II diabetes mellitus. Studies have shown its use is associated with a reduction in major cardiovascular events (MACE) in patients with type 2 diabetes such as hospitalization for acute myocardial infarction, stroke, transient ischemic attack, or cardiovascular death. There is also a suggestion that metformin may have effects beyond those relating to lowering of blood sugar. The goal of this review is to assess the effects of metformin in coronary artery disease (CAD), but more importantly, its effects on disease states other than CAD.

Cardio-renal effect of dapagliflozin and dapagliflozin- saxagliptin combination on CD34 + ve hematopoietic stem cells (HSCs) and podocyte specific markers in type 2 diabetes (T2DM) subjects: a randomized trial

INTRODUCTION

Effects of Dapagliflozin (Dapa) and Dapagliflozin-Saxagliptin combination (Combo) was examined on peripheral blood derived CD34 + Hematopoetic Stem Cells (HSCs) as a cellular CVD biomarker. Both Dapa (a sodium-glucose co-transporter 2 or SGLT2, receptor inhibitor) and Saxagliptin (a Di-peptydl-peptidase-4 or DPP4 enzyme inhibitor) are commonly used type 2 diabetes mellitus or T2DM medications, however the benefit of using the combination has not been evaluated for cardio-renal risk assessment, in a real-life practice setting, compared to a placebo.

HYPOTHESIS

We hypothesized that Dapa will improve the outcomes when compared to placebo and the Combo maybe even more beneficial.

METHODS

This is a pilot study evaluating low dose Dapagliflozin 10 mg or low dose Dapa + low dose Saxagliptin combination. 15 subjects were enrolled in 16 weeks, double-blind, three-arm, randomized placebo matched trial, with 10mg Dapa + Saxa placebo (n = 4), 10 mg Dapa + 5 mg Saxa (n = 5) Combo, And Dapa placebo + Saxa placebo (n = 6), Placebo groups. T2DM subjects (age 30-70 yrs) with HbA1c of 7-10%, were included. CD34 + HSC number, migration, mRNA expression along with biochemistry and urine exosomes were measured. Data were collected at week 0, 8, and 16. For statistics, a mixed model regression analysis was used.

RESULTS

Significant HbA1c (p = 0.0357) reduction was noted in Combo group versus Dapa alone and Placebo. hsCRP levels (P = 0.0317) and IL-6, two important inflammatory molecules, were significantly reduced in both Dapa and Combo vs. Placebo. Leptin levels decreased significantly in both Dapa alone (p = 0.035) and Combo group(p = 0.015), vs. Placebo, however the Adiponectin levels were higher in Dapa alone group. Dapagliflozin alone reduced lipid parameters significantly particularly triglyceride (TG) when compared to placebo, with resultant visit 3 values at 99.5 ± 7.2 vs. 129 ± 12.3 and LDL/HDL ratio values were similar at 2.18 ± 0.08 vs. 2.13 ± 0.15. CD34 + cell migration improved significantly in both Dapa alone (p = 0.05) and Combo group (p = 0.05) vs. Placebo.

CONCLUSIONS

Several parameters showed significant improvement with both Dapa alone and Combo compared to placebo. However, when all outcome measures were taken into account, other than glycemic control the Combo didn't seem to offer any further benefit, over Dapa alone. Therefore, contrary to our initial hypothesis we do not believe the more expensive Dapa + Saxa combination offers any specific cardiovascular benefit compared to Dapagliflozin alone. However it is noteworthy that both Dapa and its combination with Saxagliptin showed significant improvement compared to placebo in T2DM, particularly when progenitor cell based numbers and function were analyzed and taken into account.

TRIAL REGISTRATION

The trial was registered with Clinical Trials.gov number NCT03660683, last updated 06052023.

Activation of the LKB1/AMPK/HIF-1α Pathway by Metformin to Promote Neovascularisation in Cerebral Ischaemia

As a difficult-to-treat neurological condition, cerebral ischemia is currently limited to treatments such as intravenous recombinant tissue plasminogen activator thrombolysis and thrombectomy. Metformin, a potent antidiabetic drug, has been reported to have an independent function in enhancing the prognosis of stroke patients, in addition to its glucose-lowering effects. However, the mechanism of action of metformin in this context remains unclear. In vivo, a rat model of permanent middle cerebral artery occlusion was established, and after administration of a low dose of 10.5 mg/mL metformin, infarct area was measured by TTC staining, and cortical blood flow was determined by laser Doppler imaging. In vitro, the study established human umbilical vein endothelial cells treated with cobalt chloride. Immunofluorescence, immunohistochemistry, and Western blot experiments were performed to observe the expression of angiogenic factors, tight junction proteins, and apoptotic factors. A TUNEL assay was utilized to appraise cell death by apoptosis. A tube formation assay and scratch assay were conducted to determine the endothelial neovascularization status. Animal experiments have revealed that the administration of the AMPK activator metformin significantly reduced the infarct area, promoted the expression of angiogenic factors, and maintained the stability of tight junction proteins in endothelial cells. Moreover, metformin reduces nerve cells apoptosis by affecting the expression of the apoptotic protein cleaved-caspase3 via the HIF-1α pathway. In vitro, the LKB1/AMPK signaling pathway is activated after hypoxic stimulation, attaining its peak within the early stages of hypoxia (1-12 h) and gradually weakening thereafter. The administration of AMPK pharmacological agonists (between 36 and 48 h) can enhance AMPK activity, which can lead to the expression of angiogenic factors, maintain the stability of tight-junction proteins in endothelial cells, and facilitate endothelial cell migration and vascular structure formation. Conversely, the AMPK inhibitors exert the opposite effects. The activation of the LKB1/AMPK/HIF-1α signaling pathway by metformin in cerebral ischemia contributes to angiogenesis, promotes tissue repair in the injured area, and enhances neurologically functional symptoms.

New Insights into the Pleiotropic Actions of Dipeptidyl Peptidase-4 Inhibitors Beyond Glycaemic Control

Dipeptidyl peptidase-4 (DPP-4) is a multifunctional serine ectopeptidase that cleaves and modifies a plethora of substrates, including regulatory peptides, cytokines and chemokines. DPP-4 is implicated in the regulation of immune response, viral entry, cellular adhesion, metastasis and chemotaxis. Regarding its numerous substrates and extensive expression inside the body, multitasking DPP-4 has been assumed to participate in different pathophysiological mechanisms. DPP-4 inhibitors or gliptins are increasingly used for the treatment of type 2 diabetes mellitus. Several reports from experimental and clinical studies have clarified that DPP-4 inhibitors exert many beneficial pleiotropic effects beyond glycaemic control, which are mediated by anti-inflammatory, anti-oxidant, anti-fibrotic and anti-apoptotic actions. The present review will highlight the most recent findings in the literature about these pleiotropic effects and the potential mechanisms underlying these benefits, with a specific focus on the potential effectiveness of DPP-4 inhibitors in coronavirus disease-19 and diabetic kidney disease.

Upregulation of Anti-Angiogenic miR-106b-3p Correlates Negatively with IGF-1 and Vascular Health Parameters in a Model of Subclinical Cardiovascular Disease: Study with Metformin Therapy

Well-controlled type 1 diabetes mellitus (T1DM) is regarded as a model of subclinical cardiovascular disease (CVD), characterized by inflammation and adverse vascular health. However, the underlying mechanisms are not fully understood. We investigated insulin-like growth factor-1 (IGF-1) and IGF-binding protein-3 (IGFBP-3) levels, their correlation to miR-106b-3p expression in a subclinical CVD model, and the cardioprotective effect of metformin. A total of 20 controls and 29 well-controlled T1DM subjects were studied. Plasma IGF-1, IGFBP-3 levels, and miR-106b-3p expression in colony-forming unit-Hills were analyzed and compared with vascular markers. miR-106b-3p was upregulated in T1DM (p < 0.05) and negatively correlated with pro-angiogenic markers CD34+/100-lymphocytes (p < 0.05) and IGF-1 (p < 0.05). IGF-1 was downregulated in T1DM (p < 0.01), which was associated with increased inflammatory markers TNF-α, CRP, and IL-10 and reduced CD34+/100-lymphocytes. IGFBP-3 had no significant results. Metformin had no effect on IGF-1 but significantly reduced miR-106b-3p (p < 0.0001). An Ingenuity Pathway analysis predicted miR-106b-3p to inhibit PDGFA, PIK3CG, GDNF, and ADAMTS13, which activated CVD. Metformin was predicted to be cardioprotective by inhibiting miR-106b-3p. In conclusion: Subclinical CVD is characterized by a cardio-adverse profile of low IGF-1 and upregulated miR-106b-3p. We demonstrated that the cardioprotective effect of metformin may be via downregulation of upregulated miR-106b-3p and its effect on downstream targets.

Endothelial progenitor cells in pregnancy-related diseases

Placental neovascularization plays a crucial role in fetomaternal circulation throughout pregnancy and is dysregulated in several pregnancy-related diseases, including preeclampsia, gestational diabetes mellitus, and fetal growth restriction. Endothelial progenitor cells (EPCs) are a heterogeneous population of cells that differentiate into mature endothelial cells, which influence vascular homeostasis, neovascularization, and endothelial repair. Since their discovery in 1997 by Asahara et al., the role of EPCs in vascular biology has garnered a lot of interest. However, although pregnancy-related conditions are associated with changes in the number and function of EPCs, the reported findings are conflicting. This review discusses the discovery, isolation, and classification of EPCs and highlights discrepancies between current studies. Overviews of how various diseases affect the numbers and functions of EPCs, the role of EPCs as biomarkers of pregnancy disorders, and the potential therapeutic applications involving EPCs are also provided.

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.

Saxagliptin promotes random skin flap survival

BACKGROUND

Flap necrosis is a common issue encountered in clinical flap transplantation surgery. Here, we assessed the effects of saxagliptin, a dipeptidyl peptidase-4 inhibitor, on flap survival and explored the underlying mechanisms.

METHODS

A dorsal McFarlane flap model was established in 36 rats, which were randomly divided into a high-dose saxagliptin (HS) group (saxagliptin, 30 mg/kg/day, n = 12), low-dose saxagliptin (LS) group (saxagliptin, 10 mg/kg/day, n = 12), and control group (n = 12). On day 7, flap survival was examined by eye in six rats from each group, along with determination of blood perfusion by laser Doppler flowmetry and angiogenesis by angiography. The remaining rats were sacrificed for harvesting of flap tissue. The status of the flap tissue was examined histopathologically by staining with hematoxylin and eosin (H&E). Oxidative stress was evaluated by determination of superoxide dismutase (SOD) activity and malonaldehyde (MDA) content. Gasdermin D (GSDMD), vascular endothelial growth factor (VEGF), tumor necrosis factor-α (TNF-α), NOD-like receptor pyrin domain containing 3 (NLRP3), interleukin (IL)-6, IL-18, Toll-like receptor 4 (TLR4), IL-1β, caspase-1, and nuclear factor-κB (NF-κB) expression were detected by immunohistochemical analysis.

RESULTS

The experimental group exhibited a larger area of flap survival, with more blood perfusion and neovascularization and better histopathological status than the control group. The degree of oxidative stress and the levels of NF-κB, TLR4, proinflammatory cytokines, and pyroptosis-associated protein were decreased in the experimental group, while the VEGF level was increased in a saxagliptin dose-dependent manner.

CONCLUSION

Saxagliptin promotes random skin flap survival.

Multimorbidity and combined interventions for patients with coronary heart disease in Chinese population: Latent class analysis of a multi-center study

BACKGROUND AND AIMS

This study aimed to explore the profile of multimorbidity phenotype clusters and their discrepancy in mortality and the efficiency of combined interventions on blood pressure, glucose and lipid in each cluster.

METHODS

Fine and Gray competing risk regression models and Kaplan-Meier curves were used to assess the association between multimorbidity and mortality and rehospitalization. Fine and Gray competing risk regression models and subgroup analyses were used to estimate the relations between combined interventions and mortality.

RESULTS

Three distinct multimorbidity clusters were observed: Class 1 named severe class, Class 2 termed moderate class, and Class 3 named mild class. Competing risk regression models revealed that patients in Class 1 have the greatest burden of mortality and rehospitalization compared to Class 3 after confounder adjustment, with HRs 1.43 (95% CI 1.30-1.56, P < 0.001) and 2.97 (95% CI 2.74-3.21, P < 0.001), respectively. The patients in Class 2 have moderate risk of mortality and rehospitalization compared to Class 3 after confounder adjustment, with HRs 1.41 (95% CI 1.30-1.52, P < 0.001) and 2.39 (95% CI 2.23-2.56, P < 0.001), respectively. Furthermore, we found that combined interventions on blood pressure, glucose and lipid simultaneously could further benefit on survival compared to each individual intervention or two in combine.

CONCLUSIONS

This study found that multimorbidity among patients with CHD was common and increased the risks of death and rehospitalization. Three multimorbidity clusters that were significantly associated with death and rehospitalization were identified. Simultaneous intervention on blood pressure, glucose and lipid level may further benefit CHD patient in survival.

The effect of metformin on cognitive function: A systematic review and meta-analysis

Most people are familiar with metformin as a diabetic treatment option. Different positive benefits have been found for it, in addition to its anti-diabetes properties. Cognitive function enhancement is the most recent characteristic that has been studied. This study aimed to look at the evidence on the effects of metformin on cognitive performance. Web of Science, PubMed, Scopus, the Cochrane Library, EMBASE, and PsycINFO databases were searched systematically. After eliminating duplicates and irrelevant documents, the findings were screened. The documents that remained were scanned and data were extracted. Nineteen studies were qualified for meta-analysis after evaluating 3827 identified records. There was no significant relationship between metformin therapy and cognitive performance in none of the studies including cross-sectionals, cohorts, and clinical trials (p > 0.05). Results show that metformin has no significant effect on improving cognitive function or protecting against any dementia including vascular dementia and Alzheimer's disease, and cognitive impairment as well.

Cardiovascular disease (CVD) risk assessment of HIV medication regimens using hematopoietic CD34+ progenitor cells

Background

To determine the effects of integrase inhibitor (INSTI) in comparison with non-INSTI-based regimens such as non-nucleoside reverse transcriptase inhibitors (NNRTIs)-based regimens on cardiovascular disease (CVD) risk in HIV+ patients without overt history of CVD or diabetes, with normal CD4:CD8 count. For CVD risk assessment we primarily used hematopoietic CD34+ progenitor cells, as a biomarker.

Methods

Nineteen male subjects, ages 32–61 years with BMI 21.0–36.0, were enrolled. This was a single time point, cross-sectional, observational study. Subjects were enrolled under 2 groups (either on INSTI-based regimen with 13 subjects or NNRTI (non-INSTI)-based regimens with 6 subjects) who were taking stable doses of HAART. The medication regimens were a combination of one NRTI (typically tenofovir–emtricitabine) plus one INSTI or NNRTI. Our outcome measures were focused on cardiovascular and endothelial cell function and systemic inflammation. Our primary outcome measures were peripheral blood-derived hematopoietic progenitor cell number (CD34 and CD133 positive), CD34+ cell function and gene expression studies. Our secondary outcomes were arterial stiffness measures and serum-based markers of inflammation.

Results

A significant increase in percentage number of progenitor cells, CD133+ cells (p = 0.004), was noted along with an increase of double progenitor mark positive CD133+/CD34+ progenitor cell population being observed in INSTI group as compared to NNRTI group, by flow cytometry. mRNA gene expression for antioxidant gene catalase was noted along with a trend toward a decrease in gene expression of inflammatory marker IL6 (p = 0.06) being observed in CD34+ from INSTI group vs NNRTI group. The plasma IL-6 and CRP levels did not change significantly between the groups. Neutrophil–Lymphocyte ratio (NLR), an important marker of inflammation, was noted to be lower in INSTI group. A mean fasting glucose level was also lower in the INSTI group compared to NNRTI group (p = 0.03). Interestingly, urine microalbumin levels were higher in the INSTI group compared to NNRTI group (p = 0.08), while eGFR levels were significantly lower in the INSTI group (p = 0.002). The arterial stiffness measures did not show statistically significant differences between the two groups.

Conclusion

We conclude that the INSTI regimen may provide a better CVD risk profile compared to NNRTI-based HAART regimen; however, the increased albuminuria along with lower eGFR, noted in INSTI group, is of concern. Because of the small size, these results would need replication in additional studies before changing clinical practice.

Clinical trial registrationhttps://clinicaltrials.gov/ct2/show/NCT03782142?cond=Hiv&spons=Sabyasachi+sen&cntry=US&state=US%3ADC&city=Washington&draw=2&rank=1. ClinicalTrials.gov Identifier: NCT03782142.

Assessment of the Relationship Between CD34 Antigen and Vitamin D Level and Insulin Resistance in Patients With Type 2 Diabetes

Diabetes causes disorders in the performance of endothelial progenitor cells, and obesity and vitamin D deficiency are associated with endothelial dysfunction and cardiovascular disease. This case-control study investigated the relationship between serum CD34 antigen and vitamin D levels and insulin resistance in type 2 diabetes. The results showed that CD34 has a significant inverse relationship with BMI, A1C, fasting blood glucose, insulin resistance, and insulin levels and has a significant direct relationship with vitamin D levels. Both CD34 and vitamin D were found to be significantly associated with type 2 diabetes. The association between reduced CD34 and vitamin D levels with type 2 diabetes and increased insulin resistance suggests that these parameters may be helpful in assessing diabetes and predicting its complications.

Sitagliptin Reduces Endothelial Dysfunction and Apoptosis Induced by High-Fat Diet and Palmitate in Thoracic Aortas and Endothelial Cells via ROS-ER Stress-CHOP Pathway

Macrovascular disease is tightly associated with obesity-induced metabolic syndrome. Sitagliptin (SIT), an orally stable selective inhibitor of Dipeptidyl peptidase-4 (DPP-4), has protective effects on endothelium. However, the mechanisms enabling SIT to exhibit resistance to diet-induced obesity (DIO) related with reactive oxygen species (ROS) and endoplasmic reticulum (ER) stress in the aorta and endothelial cells have not been reported yet. Therefore, the present study was conducted to determine if SIT exerts protective role in the thoracic aortas isolated from the high-fat diet (HFD)-treated rats and palmitate (PA)-treated endothelial cells by alleviating ROS and ER stress. Male Sprague Dawley rats were randomly divided into standard chow diet (SCD), HFD and HFD plus sitagliptin administration (HFD + SIT) groups. The rats of latter two groups were given HFD fodder for 12 weeks, then the HFD + SIT rats were treated with SIT (10 mg/kg/d) by intragastric administration for another 8 weeks. The body mass, vascular tension, serum oxidative stress indices and inflammatory parameters, pathological changes, protein expression of endothelial nitric oxide synthase (eNOS), the genes associated with ER stress and apoptosis in the thoracic aorta were measured. Furthermore, cell proliferation, ROS and the protein expression associated with ER stress (especially CHOP) and apoptosis were assessed in human umbilical vein endothelial cells (HUVECs) incubated with SIT and PA. Compared to the SCD rats, the HFD rats had higher serum lipid levels, decreased vascular tension, increased inflammation, oxidative and ER stress, and apoptosis of endothelial cells. PA promoted ROS generation, ER stress and apoptosis, inhibited cell proliferation in HUVECs. SIT treatment obviously ameliorated apoptosis via alleviating ROS and ER stress in the thoracic aortas isolated from HFD-fed rats and PA-treated HUVECs. The results suggest that SIT improved endothelial function via promoting cell proliferation and alleviating ROS-ER stress-CHOP pathway both in vivo and in vitro.

Association between dipeptidyl peptidase-4 inhibitors use and leptin in type 2 diabetes mellitus

BACKGROUND

Dipeptidyl peptidase-4 inhibitors (DPP-4i) provide a unique antihyperglycemic effect by regulating incretin peptides in type 2 diabetes mellitus (T2DM) patients who are inadequately controlled with insulin therapy. The aim of this study was to investigate the impact of DPP-4i on leptin concentrations in subjects with T2DM.

METHODS

Randomized controlled trials (RCTs) with comparators were systematically searched through PubMed, Embase, and the Cochrane Library. Quantitative analysis was performed with a fixed or random-effects model according to heterogeneity. Publication bias was evaluated by using the standard methods for sensitivity analysis.

RESULTS

Ten trials with 698 patients with T2DM were included. Pooled analysis demonstrated that DPP-4i did not significantly change leptin concentrations (1.31 ng/mL, 95 % CI - 0.48 to 3.10). DPP-4i exerted effects on modulating leptin levels compared to active comparators (0.21 ng/mL, 95 % CI - 1.37 to 1.78). Meta-analysis was powerful and stable after sensitivity analysis.

CONCLUSIONS

DPP-4i did not modulate leptin concentrations in T2DM and exerted no stronger effects than traditional antidiabetic agents.

Role of Canagliflozin on function of CD34+ve endothelial progenitor cells (EPC) in patients with type 2 diabetes

BACKGROUND

Endothelial progenitor cells (EPCs) has been shown to be dysfunctional in both type 2 diabetes mellitus (T2DM) and chronic kidney disease (CKD) leading to poor regeneration of endothelium and renal perfusion. EPCs have been shown to be a robust cardiovascular disease (CVD) risk indicator. Effect of sodium glucose channel inhibitors (SGLT2i) such as Canagliflozin (CG) on a cellular biomarker such as CD34+ve progenitor cells, which may help predict CVD risk, in patients with T2DM with established CKD has not been explored.

METHODS

This is a pilot study where 29 subjects taking metformin and/or Insulin were enrolled in a 16 week, double blind, randomized placebo matched trial, with a low dose 100 mg CG as the intervention group compared to matched placebo. Type 2 diabetes subjects (30-70 years old), with hemoglobin A1c (HbA1c) of 7-10%, were enrolled. CD34+ve cell number, migratory function, gene expression along with vascular parameters such as arterial stiffness, serum biochemistry pertaining to cardio-metabolic health, resting energy expenditure and body composition were measured. Data were collected at week 0, 8 and 16. A mixed model regression analysis was done and p value less than 0.05 was considered statistically significant.

RESULTS

A significant expression of CXCR4 receptor with a concomittant increase in migratory function of CD34+ve cells was observed in CG treated group as compared to placebo group. Gene expression analysis of CD34+ve cells showed an increase in expression of antioxidants (superoxide dismutase 2 or SOD2, Catalase and Glutathione Peroxidase or GPX) and notable endothelial markers (PECAM1, VEGF-A, and NOS3). A significant reduction in glucose and HbA1c levels were observed along with improved systolic and diastolic blood pressure in the CG group. A significant increase in adiponectin (p = 0.006) was also noted in treatment group. Urinary exosomal protein leak in urine, examining podocyte health (podocalyxin, Wilm's tumor and nephrin) showed reduction with CG CONCLUSION: Low dose Canagliflozin has a beneficial effect on CD34+ cell function, serum biochemistry and urinary podocyte specific exosomes in type 2 diabetes.

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.

Where Does Metformin Stand in Modern Day Management of Type 2 Diabetes?

Metformin is the most commonly used glucose-lowering therapy (GLT) worldwide and remains the first-line therapy for newly diagnosed individuals with type 2 diabetes (T2D) in management algorithms and guidelines after the UK Prospective Diabetes Study (UKPDS) showed cardiovascular mortality benefits in the overweight population using metformin. However, the improved Major Adverse Cardiovascular Events (MACE) realised in some of the recent large cardiovascular outcomes trials (CVOTs) using sodium-glucose co-transporter 2 inhibitors (SGLT2i) and glucagon-like peptide-1 receptor agonists (GLP-1RA) have challenged metformin's position as a first-line agent in the management of T2D. Many experts now advocate revising the existing treatment algorithms to target atherosclerotic cardiovascular disease (ASCVD) and improving glycaemic control as a secondary aim. In this review article, we will revisit the major cardiovascular outcome data for metformin and include a critique of the UKPDS data. We then review additional factors that might be pertinent to metformin's status as a first-line agent and finally answer key questions when considering metformin's role in the modern-day management of T2D.

Bioinformatics and machine learning in gastrointestinal microbiome research and clinical application

The scientific community currently defines the human microbiome as all the bacteria, viruses, fungi, archaea, and eukaryotes that occupy the human body. When considering the variable locations, composition, diversity, and abundance of our microbial symbionts, the sheer volume of microorganisms reaches hundreds of trillions. With the onset of next generation sequencing (NGS), also known as high-throughput sequencing (HTS) technologies, the barriers to studying the human microbiome lowered significantly, making in-depth microbiome research accessible. Certain locations on the human body, such as the gastrointestinal, oral, nasal, and skin microbiomes have been heavily studied through community-focused projects like the Human Microbiome Project (HMP). In particular, the gastrointestinal microbiome (GM) has received significant attention due to links to neurological, immunological, and metabolic diseases, as well as cancer. Though HTS technologies allow deeper exploration of the GM, data informing the functional characteristics of microbiota and resulting effects on human function or disease are still sparse. This void is compounded by microbiome variability observed among humans through factors like genetics, environment, diet, metabolic activity, and even exercise; making GM research inherently difficult to study. This chapter describes an interdisciplinary approach to GM research with the goal of mitigating the hindrances of translating findings into a clinical setting. By applying tools and knowledge from microbiology, metagenomics, bioinformatics, machine learning, predictive modeling, and clinical study data from children with treatment-resistant epilepsy, we describe a proof-of-concept approach to clinical translation and precision application of GM research.

Using adult stem cells to monitor endothelial dysfunction in diabetes mellitus

Diabetes affects approximately 10.5% of adults in the United States and this is projected to nearly double by 2025. Both type 2 diabetes (T2DM) and obesity are associated with endothelial dysfunction, oxidative stress, endothelial cell inflammation, cardiovascular pro-thrombotic states and are the most common causes of endothelial dysfunction, chronic kidney disease (CKD) and cardiovascular disease (CVD). Lately several new diabetes medications have come to clinical use that claim CVD risk improvement, however modalities used to test and monitor CVD risk are not cell based, which bring into question the reproducibility of these studies. Our review is designed to highlight cardiovascular risk reduction with novel diabetes medications while emphasizing cellular outcomes as a biomarker of cardiovascular risk. We are going to highlight studies that comment on peripheral blood derived CD34+ hematopoietic progenitor cells, as biomarkers of endothelial function. CD34+ cells have been extensively investigated by us and several other laboratories for the last two decades, as a viable cardiovascular function biomarker. In this context we will also discuss relevant CVD risk reduction trials that used novel diabetes medications.

Linagliptin, when compared to placebo, improves CD34+ve endothelial progenitor cells in type 2 diabetes subjects with chronic kidney disease taking metformin and/or insulin: a randomized controlled trial

BACKGROUND

Endothelial Progenitor cells (EPCs) has been shown to be dysfunctional in both type 2 diabetes mellitus (T2DM) and chronic kidney disease (CKD) leading to poor regeneration of endothelium and renal perfusion. EPCs have been shown to be a robust cardiovascular disease (CVD) risk indicator. Cellular mechanisms of DPP4 inhibitors such as linagliptin (LG) on CVD risk, in patients with T2DM with established CKD has not been established. Linagliptin, a DPP4 inhibitor when added to insulin, metformin or both may improve endothelial dysfunction in a diabetic kidney disease (DKD) population.

METHODS

31 subjects taking metformin and/or Insulin were enrolled in this 12 weeks, double blind, randomized placebo matched trial, with 5 mg LG compared to placebo. Type 2 diabetes subjects (30-70 years old), HbA1c of 6.5-10%, CKD Stage 1-3 were included. CD34+ cell number, migratory function, gene expression along with vascular parameters such as arterial stiffness, biochemistry, resting energy expenditure and body composition were measured. Data were collected at week 0, 6 and 12. A mixed model regression analysis was done with p value < 0.05 considered significant.

RESULTS

A double positive CD34/CD184 cell count had a statistically significant increase (p < 0.02) as determined by flow cytometry in LG group where CD184 is SDF1a cell surface receptor. Though mRNA differences in CD34+ve was more pronounced CD34- cell mRNA analysis showed increase in antioxidants (superoxide dismutase 2 or SOD2, Catalase and Glutathione Peroxidase or GPX) and prominent endothelial markers (PECAM1, VEGF-A, vWF and NOS3). Arterial stiffness measures such as augmentation Index (AI) (p < 0.04) and pulse wave analysis (PWV) were improved (reduced in stiffness) in LG group. A reduction in LDL: HDL ratio was noted in treatment group (p < 0.04). Urinary exosome protein examining podocyte health (podocalyxin, Wilms tumor and nephrin) showed reduction or improvement.

CONCLUSIONS

In DKD subjects, Linagliptin promotes an increase in CXCR4 expression on CD34 + progenitor cells with a concomitant improvement in vascular and renal parameters at 12 weeks. Trial Registration Number NCT02467478 Date of Registration: 06/08/2015.

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.

miR145 Regulates the Proliferation and Apoptosis of Rat Vascular Endothelial Cells under Hyperglycemia by Targeting the ANGPT2 Gene and Involving the NFκB Signaling Pathway

PURPOSE

A majority of diabetes mellitus patients with disturbances of glucose metabolism present with vascular complications. This study aimed to explore regulatory mechanisms of miR145 and its potential target gene ANGPT2 on diabetic vasculopathy under hyperglycemia.

METHODS

Based on the fact that miR145 is detected in rat aortic endothelial cells (RAECs) under hyperglycemia, RAECs were transfected with miR145 mimics/inhibitor for further confirmation. RAEC proliferation was detected with CCK8 assays, and cell apoptosis and CD34⁺-cell population with annexinV-PI staining and anti-CD34FITC on flow cytometry, respectively. Then, qPCR and Western blot were applied to detect mRNA and protein expression of ANGPT2 and involved pathway factor NFκB p65. Subsequently, dual luciferase-reporter gene analysis was utilized to verify whether miR145 acted directly upon the 3'UTR of ANGPT2 mRNA.

RESULTS

The ANGPT2 gene was confirmed to be a direct target of miR145. miR145 mimics markedly downregulated the expression of ANGPT2 and NFκB p65, boosted the percentage of the CD34⁺ phenotype, and promoted proliferation and suppressed apoptosis of RAECs under hyperglycemia.

CONCLUSION

miR145 might regulate the viability of RAECs via targeting ANGPT2 and involving NFκB signaling to exert a protective effect on diabetic vasculature.

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.

Adult Stem Cells: Beyond Regenerative Tool, More as a Bio-Marker in Obesity and Diabetes

Obesity, diabetes, and cardiovascular diseases are increasing rapidly worldwide and it is therefore important to know the effect of exercise and medications for diabetes and obesity on adult stem cells. Adult stem cells play a major role in remodeling and tissue regeneration. In this review we will focus mainly on two adult stem/progenitor cells such as endothelial progenitor cells and mesenchymal stromal cells in relation to aerobic exercise and diabetes medications, both of which can alter the course of regeneration and tissue remodelling. These two adult precursor and stem cells are easily obtained from peripheral blood or adipose tissue depots, as the case may be and are precursors to endothelium and mesenchymal tissue (fat, bone, muscle, and cartilage). They both are key players in maintenance of cardiovascular and metabolic homeostasis and can act also as useful biomarkers.

DPP-4 inhibitor saxagliptin ameliorates oxygen deprivation/reoxygenation-induced brain endothelial injury

Cardiovascular diseases are the main cause of death and disability among diabetes patients. Atherosclerosis-associated stroke is one of the most severe complications in diabetes patients. DPP-4 inhibitors are a class of potent anti-glycemic agents used to treat diabetes. Recently, some DPP-4 inhibitors have been shown to have cardiovascular benefits. In this study, we reveal that saxagliptin, one of the most widely used DPP-4 inhibitors, exhibits vascular protective effects against oxygen and glucose depletion/reoxygenation (OGD/R) in human brain vascular endothelial cells. Our data show that DPP-4 is fairly expressed in brain endothelial cells and its expression is induced by OGD/R. The results of MTT assay show that inhibition of DPP-4 by saxagliptin ameliorates OGD/R-induced reduced cell viability, and LDH assay demonstrated that saxagliptin reduces cellular toxicity. Furthermore, we show that saxagliptin mitigates OGD/R-induced collapse of mitochondrial membrane potential (MMP). Saxagliptin also reduces oxidative stress-induced release of 4-HNE and the NAPDH oxidase catalytic subunit NOX-4. At the molecular level, saxagliptin suppresses OGD/R-induced expression of pro-inflammatory cytokines and production of vascular adhesion molecules including tumor necrosis factor-α (TNF-α), interleukin (IL)-6, monocyte chemoattractant protein 1 (MCP-1), vascular cellular adhesion molecule 1 (VCAM-1), and E-selectin. Mechanistically, saxagliptin inhibits activation of the NF-κB pathway by OGD/R via its inhibitory effect on nuclear p65 and NF-κB promoter activity. Collectively, our study explicitly demonstrates the cellular protective effect of saxagliptin against OGD/R-induced brain endothelial injury. Our findings extend our recognition of the protective roles of DPP-4 inhibitors in brain vascular cells.

Metformin therapy in patients with diabetes mellitus is associated with a reduced risk of vasculopathy and cardiovascular mortality after heart transplantation

Background

Cardiac allograft vasculopathy (CAV) is a major cause of morbidity and mortality following heart transplantation (HT). Reduced cardiovascular mortality and morbidity have been reported in non-HT patients treated with metformin. Given the high prevalence of type 2 diabetes mellitus (T2DM) in HT patients, we investigated the association between metformin therapy and cardiovascular outcomes after HT.

Methods

The study population comprised 103 DM patients who had undergone HT between 1994 and 2018 and were prospectively followed-up. We excluded from the study patients with type 1 diabetes mellitus. Fifty-five HT patients (53%) in the cohort were treated with metformin. Clinical data were recorded on prospectively designed forms. The primary outcomes included CAV, survival, and the combined end-point of CAV or cardiovascular mortality.

Results

Kaplan–Meier survival analysis showed that the CAV rate at 20 years of follow-up was lower in DM patients treated with metformin than in those who were not (30 vs. 65%; log-rank p = 0.044). Similarly, the combined risk of CAV or cardiovascular mortality was lower in the metformin-treated patients than in those not receiving metformin (32 vs. 68%; log rank p = 0.01). Consistently, multivariate analysis adjusted for age and comorbidities showed that metformin therapy was independently associated with a significant 90% reduction (95% confidence interval 0.02–0.46, p = 0.003) in the risk for the development of CAV, and a 91% reduction (95% confidence interval 0.02–0.42; p = 0.003) in the risk for CAV or cardiovascular mortality.

Conclusions

In diabetic HT patients, metformin therapy is independently associated with a significant reduction in the long-term risk for CAV and the combined end-point of CAV or cardiovascular mortality after HT.

Effect of DPP-IV Inhibitors on Glycemic Variability in Patients with T2DM: A Systematic Review and Meta-Analysis

Glycemic variability (GV) has been an emerging target for preventing complications related to type 2 diabetes. For reducing GV, DPP-IV inhibitors have shown effectiveness compared to other oral anti-hyperglycemic drugs (OADs), but systematic evaluation has yet to be existed. A systematic review and meta-analysis of randomized controlled trials (RCTs) were performed to evaluate the effect of DPP-IV inhibitors compared with other OADs, on GV as measured by mean amplitude of glycemic excursions (MAGE). Searches were conducted using Pubmed, EMBASE, and the Cochrane Library, from which eligible studies were retrieved; seven RCTs were included in the analysis. DPP-IV inhibitors were found to significantly reduce MAGE compared to other OADs (mean difference = -14.61; 95% CI = -19.00 to -10.21; p < 0.0001) without significant heterogeneity among sulfonylureas (mean difference = -14.93; 95% CI = -21.60 to -8.26; p < 0.0001). Initial combination therapy with DPP-IV inhibitors more effectively reduced MAGE than stepwise add-on therapies (p = 0.006), although no differences in MAGE were found based on HbA1c values. These findings indicate that DPP-IV inhibitors are promising alternatives for reducing GV in type 2 diabetes patients. However, further studies utilizing larger numbers of patients and longer-term follow-ups are needed.

Effect of metformin on all-cause and cardiovascular mortality in patients with coronary artery diseases: a systematic review and an updated meta-analysis

BACKGROUND

Metformin is the most widely prescribed drug to lower glucose and has a definitive effect on the cardiovascular system. The goal of this systematic review and meta-analysis is to assess the effects of metformin on mortality and cardiac function among patients with coronary artery disease (CAD).

METHODS

Relevant studies reported before October 2018 was retrieved from databases including PubMed, EMBASE, Cochrane Library and Web of Science. Hazard ratio (HR) was calculated to evaluate the all-cause mortality, cardiovascular mortality and incidence of cardiovascular events (CV events), to figure out the level of left ventricular ejection fraction (LVEF), creatine kinase MB (CK-MB), type B natriuretic peptide (BNP) and to compare the average level of low density lipoprotein (LDL).

RESULTS

In this meta-analysis were included 40 studies comprising 1,066,408 patients. The cardiovascular mortality, all-cause mortality and incidence of CV events were lowered to adjusted HR (aHR) = 0.81, aHR = 0.67 and aHR = 0. 83 respectively after the patients with CAD were given metformin. Subgroup analysis showed that metformin reduced all-cause mortality in myocardial infarction (MI) (aHR = 0.79) and heart failure (HF) patients (aHR = 0.84), the incidence of CV events in HF (aHR = 0.83) and type II diabetes mellitus (T2DM) patients (aHR = 0.83), but had no significant effect on MI (aHR = 0.87) and non-T2DM patients (aHR = 0.92). Metformin is superior to sulphonylurea (aHR = 0.81) in effects on lowering the incidence of CV events and in effects on patients who don't use medication. The CK-MB level in the metformin group was lower than that in the control group standard mean difference (SMD) = - 0.11). There was no significant evidence that metformin altered LVEF (MD = 2.91), BNP (MD = - 0.02) and LDL (MD = - 0.08).

CONCLUSION

Metformin reduces cardiovascular mortality, all-cause mortality and CV events in CAD patients. For MI patients and CAD patients without T2DM, metformin has no significant effect of reducing the incidence of CV events. Metformin has a better effect of reducing the incidence of CV events than sulfonylureas.

The protective effects of saxagliptin against lipopolysaccharide (LPS)-induced inflammation and damage in human dental pulp cells

Bacteria play a pivotal role in the pathological initiation and progression of pulpitis. Lipopolysaccharide (LPS) is recognized as a major component of the outer wall of Gram-negative bacteria. Saxagliptin, a potent inhibitor of dipeptidyl peptidase-4 (DPP-4), has been licensed for the treatment of type 2 diabetes. In this study, we aimed to evaluate the protective effects of saxagliptin against LPS-induced intracellular insults in human dental pulp cells (HDPCs). We found that DPP-4 is expressed in HDPCs. Interestingly, the expression of DPP-4 was increased in response to LPS treatment. We also found that saxagliptin ameliorated LPS-induced production of ROS and reduction of glutathione (GSH). Additionally, saxagliptin prevented LPS-induced mitochondrial dysfunction by increasing the levels of mitochondrial membrane potential (MMP) and the production of adenosine triphosphate (ATP). Importantly, saxagliptin ameliorated LPS-induced reduction of cell viability and lactate dehydrogenase (LDH) release. Our results indicate that saxagliptin significantly inhibited LPS-induced expression and secretions of tumour necrosis factor alpha (TNF-α), interleukin (IL)-1β and IL-6 in HDPCs. Mechanistically, we found that saxagliptin inhibited the phosphorylation of p38 and the activation of NF-κB. Our findings suggest that saxagliptin might have a potential therapeutic capacity for the treatment of pulpitis through mitigating inflammatory signalling in dental pulp cells.

Reassessing the effects of continuous positive airway pressure (CPAP) on arterial stiffness and peripheral blood derived CD34+ progenitor cells in subjects with sleep apnea

Background

Obstructive sleep apnea (OSA) is an independent risk factor for cardiovascular diseases (CVD) and vascular health. Peripheral blood-derived CD34+ progenitor cells have been used as biomarker for CVD risk and may play a similar role in OSA and CVD risk assessment. Although there are some controversial results in the literature, OSA patients may have a reduction in the number and function of CD34+ cells. The damages promoted by OSA in CD34+ cells may lead to an increase in endothelial oxidative stress and endothelial inflammation which may lead to a reduced endothelial repair capacity. In this study, we explored the effect of continuous positive airway pressure (CPAP) on peripheral blood-derived CD34+ cells and arterial stiffness (another predictor of endothelial health and CVD risk) in OSA patients.

Methods and results

Nine overweight and obese subjects without prediabetes or diabetes were recruited. Eight out of nine subjects had moderate to severe degree of OSA. CD34+ cells were isolated from peripheral blood. Number and function of these cells were monitored before and after 3 months of treatment with CPAP. No significant changes were observed in the number of CD34+ cells, CFU-Hill’s colony formation unit (CFU) count or migratory response to the chemotactic factor SDF-1a after CPAP use. However, CXCR4 mRNA expression significantly increased by 2.2-fold indicating that CPAP may have a positive effect on SDF1a receptor (CXCR4), thereby improving migration of CD34+ cells mediated by SDF1a after the 3 month period. Interestingly, in clinical arena our results showed a reduction of pulse wave velocity (an established parameter of arterial stiffness) following CPAP therapy.

Conclusions

Our findings suggest that 3-month CPAP intervention does not show statistical significant increase in CD34+ cell number and function, in mostly moderate to severe OSA subjects; however, it did demonstrate a positive trend. CPAP therapy, did help improve arterial stiffness parameter.

Electronic supplementary material

The online version of this article (10.1186/s13287-019-1251-8) contains supplementary material, which is available to authorized users.

Metformin in patients with and without diabetes: a paradigm shift in cardiovascular disease management

With an increasing global burden of coronary artery disease (CAD), early detection and timely management of risk factors are crucial to reduce morbidity and mortality in such patients. Diabetes mellitus (DM) is considered an independent risk factor for the development of CAD. Metformin, an anti-diabetic drug, has been shown in pre-clinical and clinical studies, to lower the cardiovascular events in the DM patients. Growing evidence suggests that metformin has a protective effect on coronary artery beyond its hypoglycemic effects. Given its global availability, route of administration and cost, metformin provides an alternate/additional therapeutic option for primary and secondary prevention of CAD in DM and non-diabetics alike. Future prospective cohort-based studies and randomized clinical trials are needed to identify 'at-risk' population who may potentially benefit from metformin.

The DPP-4 inhibitor saxagliptin ameliorates ox-LDL-induced endothelial dysfunction by regulating AP-1 and NF-κB

Diabetes-associated cardiovascular complications are the leading cause of death for diabetic patients. Dipeptidyl peptidase 4 (DPP-4) inhibitor agents, known as gliptins, are a class of potent anti-glycemic agents developed to treat diabetes. Recently, gliptins have been shown to have independent cardiovascular benefits. In this study, we revealed the protective role of saxagliptin in vascular endothelial cells. Our data show that saxagliptin suppresses oxidized low-density lipoprotein cholesterol (ox-LDL)-induced expression of its receptor lectin-like ox-LDL receptor-1 (LOX-1). Saxagliptin treatment reduces ox-LDL-induced production of cytokines and vascular adhesion molecules including tumor necrosis factor (TNF-α), interleukin-1β (IL-1β), vascular cell adhesion molecule 1 (VCAM-1), and intercellular cell adhesion molecule-1 (ICAM-1). The presence of saxagliptin suppressed ox-LDL-induced adhesion of monocytes to endothelial cells in co-culture adhesion experiments. Moreover, saxagliptin mitigated ox-LDL-induced production of reactive oxygen species and suppressed elevated expression of endothelial nicotinamide adenine dinucleotide phosphate oxidase subunit (NOX-4) induced by ox-LDL. Mechanistically, saxagliptin exerted inhibitory effects against ox-LDL-induced phosphorylation of JNK kinase, expression of the activator protein 1 (AP-1) subunits c-Jun/c-fos, and AP-1 promoter activity. Saxagliptin also suppressed nuclear factor κB (NF-κB) p65 accumulation and inhibited its promoter activity. Our data elaborate the molecular mechanism of saxagliptin-mediated endothelial protection and indicate that saxagliptin could have vascular benefits independent on its anti-glycemic function.