Dapagliflozin reduces systemic inflammation in patients with type 2 diabetes without known heart failure.

OBJECTIVE: Sodium glucose cotransporter 2 (SGLT2) inhibitors significantly improve cardiovascular outcomes in diabetic patients; however, the mechanism is unclear. We hypothesized that dapagliflozin improves cardiac outcomes via beneficial effects on systemic and cardiac inflammation and cardiac fibrosis. RESEARCH AND DESIGN METHODS: This randomized placebo-controlled clinical trial enrolled 62 adult patients (mean age 62, 17% female) with type 2 diabetes (T2D) without known heart failure. Subjects were randomized to 12 months of daily 10 mg dapagliflozin or placebo. For all patients, blood/plasma samples and cardiac magnetic resonance imaging (CMRI) were obtained at time of randomization and at the end of 12 months. Systemic inflammation was assessed by plasma IL-1B, TNFα, IL-6 and ketone levels and PBMC mitochondrial respiration, an emerging marker of sterile inflammation. Global myocardial strain was assessed by feature tracking; cardiac fibrosis was assessed by T1 mapping to calculate extracellular volume fraction (ECV); and cardiac tissue inflammation was assessed by T2 mapping. RESULTS: Between the baseline and 12-month time point, plasma IL-1B was reduced (- 1.8 pg/mL, P = 0.003) while ketones were increased (0.26 mM, P = 0.0001) in patients randomized to dapagliflozin. PBMC maximal oxygen consumption rate (OCR) decreased over the 12-month period in the placebo group but did not change in patients receiving dapagliflozin (- 158.9 pmole/min/106 cells, P = 0.0497 vs. - 5.2 pmole/min/106 cells, P = 0.41), a finding consistent with an anti-inflammatory effect of SGLT2i. Global myocardial strain, ECV and T2 relaxation time did not change in both study groups. GOV REGISTRATION: NCT03782259.

Elevated levels of interleukin-12/23p40 may serve as a potential indicator of dysfunctional heart rate variability in type 2 diabetes.

BACKGROUND: Systemic inflammatory processes plausibly contribute to the development of cardiovascular complications, causing increased morbidity and mortality in type 2 diabetes. Circulating inflammatory markers, i.e., interleukin (IL)-6 and tumour necrosis factor-α, are associated with neurocardiac measures. We examined a broad panel of various inflammatory and inflammation-related serum markers to obtain more detailed insight into the possible neuro-immune interaction between cardiovascular regulation and systemic level of inflammation. METHODS: Serum samples from 100 participants with type 2 diabetes were analysed. Heart rate variability, cardiovascular autonomic reflex tests, and cardiac vagal tone tests were performed based on electrocardiographic readings. Data regarding covariates (demographic-, diabetes-, and cardiovascular risk factors) were registered. RESULTS: Increased serum levels of IL-12/IL-23p40 (p < 0.01) and intercellular adhesion molecule (ICAM)-1 (p < 0.007) were associated with diminished heart rate variability measures. After all adjustments, the associations between IL-12/23p40, SDANN and VLF persisted (p = 0.001). Additionally, serum levels of vascular endothelial growth factor (VEGF)-C were associated with response to standing (p = 0.005). DISCUSSION: The few but robust associations between neurocardiac regulation and serum markers found in this study suggest systemic changes in proinflammatory, endothelial, and lymphatic function, which collectively impacts the systemic cardiovascular function. Our results warrant further exploration of IL-12/IL-23p40, ICAM-1, and VEGF-C as possible cardiovascular biomarkers in T2D that may support future decisions regarding treatment strategies for improved patient care.

FNDC5/Irisin attenuates diabetic cardiomyopathy in a type 2 diabetes mouse model by activation of integrin αV/ß5-AKT signaling and reduction of oxidative/nitrosative stress.

Irisin, the cleaved form of the fibronectin type III domain containing 5 (FNDC5) protein, is involved in metabolism and inflammation. Recent findings indicated that irisin participated in cardiovascular physiology and pathology. In this study, we investigated the effects of FNDC5/irisin on diabetic cardiomyopathy (DCM) in type 2 diabetic db/db mice. Downregulation of myocardial FNDC5/irisin protein expression and plasma irisin levels was observed in db/db mice compared to db/+ controls. Moreover, echocardiography revealed that db/db mice exhibited normal cardiac systolic function and impaired diastolic function. Adverse structural remodeling, including cardiomyocyte apoptosis, myocardial fibrosis, and cardiac hypertrophy were observed in the hearts of db/db mice. Sixteen-week-old db/db mice were intramyocardially injected with adenovirus encoding FNDC5 or treated with recombinant human irisin via a peritoneal implant osmotic pump for 4 weeks. Both overexpression of myocardial FNDC5 and exogenous irisin administration attenuated diastolic dysfunction and cardiac structural remodeling in db/db mice. Results from in vitro studies revealed that FNDC5/irisin protein expression was decreased in high glucose (HG)/high fat (HF)-treated cardiomyocytes. Increased levels of inducible nitric oxide synthase (iNOS), NADPH oxidase 2 (NOX2), 3-nitrotyrosine (3-NT), reactive oxygen species (ROS), and peroxynitrite (ONOO-) in HG/HF-treated H9C2 cells provided evidence of oxidative/nitrosative stress, which was alleviated by treatment with FNDC5/irisin. Moreover, the mitochondria membrane potential (ΔΨm) was decreased and cytochrome C was released from mitochondria with increased levels of cleaved caspase-3 in HG/HF-treated H9C2 cells, indicating the presence of mitochondria-dependent apoptosis, which was partially reversed by FNDC5/irisin treatment. Mechanistic studies showed that activation of integrin αVß5-AKT signaling and attenuation of oxidative/nitrosative stress were responsible for the cardioprotective effects of FNDC5/irisin. Therefore, FNDC5/irisin mediates cardioprotection in DCM by inhibiting myocardial apoptosis, myocardial fibrosis, and cardiac hypertrophy. These findings implicate that FNDC5/irisin as a potential therapeutic intervention for DCM, especially in type 2 diabetes mellitus (T2DM).

Metformin impairs homing ability and efficacy of mesenchymal stem cells for cardiac repair in streptozotocin-induced diabetic cardiomyopathy in rats.

Bone marrow-derived mesenchymal stem cells (BM-MSCs) have demonstrated potential in treating diabetic cardiomyopathy. However, patients with diabetes are on multiple drugs and there is a lack of understanding of how transplanted stem cells would respond in presence of such drugs. Metformin is an AMP kinase (AMPK) activator, the widest used antidiabetic drug. In this study, we investigated the effect of metformin on the efficacy of stem cell therapy in a diabetic cardiomyopathy animal model using streptozotocin (STZ) in male Wistar rats. To comprehend the effect of metformin on the efficacy of BM-MSCs, we transplanted BM-MSCs (1 million cells/rat) with or without metformin. Our data demonstrate that transplantation of BM-MSCs prevented cardiac fibrosis and promoted angiogenesis in diabetic hearts. However, metformin supplementation downregulated BM-MSC-mediated cardioprotection. Interestingly, both BM-MSCs and metformin treatment individually improved cardiac function with no synergistic effect of metformin supplementation along with BM-MSCs. Investigating the mechanisms of loss of efficacy of BM-MSCs in the presence of metformin, we found that metformin treatment impairs homing of implanted BM-MSCs in the heart and leads to poor survival of transplanted cells. Furthermore, our data demonstrate that metformin-mediated activation of AMPK is responsible for poor homing and survival of BM-MSCs in the diabetic heart. Hence, the current study confirms that a conflict arises between metformin and BM-MSCs for treating diabetic cardiomyopathy. Approximately 10% of the world population is diabetic to which metformin is prescribed very commonly. Hence, future cell replacement therapies in combination with AMPK inhibitors may be more effective for patients with diabetes.NEW & NOTEWORTHY Metformin treatment reduces the efficacy of mesenchymal stem cell therapy for cardiac repair during diabetic cardiomyopathy. Stem cell therapy in diabetics may be more effective in combination with AMPK inhibitors.

Circulating long chain acylcarnitines and outcomes in diabetic heart failure: an HF-ACTION clinical trial substudy.

BACKGROUND: Whether differences in circulating long chain acylcarnitines (LCAC) are seen in heart failure (HF) patients with and without diabetes mellitus (DM), and whether these biomarkers report on exercise capacity and clinical outcomes, remains unknown. The objective of the current study was to use metabolomic profiling to identify biomarkers that report on exercise capacity, clinical outcomes, and differential response to exercise in HF patients with and without DM. METHODS: Targeted mass spectrometry was used to quantify metabolites in plasma from participants in the heart failure: a controlled trial investigating outcomes of exercise training (HF-ACTION) trial. Principal components analysis was used to identify 12 uncorrelated factors. The association between metabolite factors, diabetes status, exercise capacity, and time to the primary clinical outcome of all-cause mortality or all-cause hospitalization was assessed. RESULTS: A total of 664 participants were included: 359 (54%) with DM. LCAC factor levels were associated with baseline exercise capacity as measured by peak oxygen consumption (beta 0.86, p = 2 × 10-7, and were differentially associated in participants with and without DM (beta 1.58, p = 8 × 10-8 vs. 0.67, p = 9 × 10-4, respectively; p value for interaction = 0.012). LCAC levels changed to a lesser extent in participants with DM after exercise (mean ∆ 0.09, p = 0.24) than in those without DM (mean ∆ 0.16, p = 0.08). In univariate and multivariate modeling, LCAC factor levels were associated with time to the primary outcome (multivariate HR 0.80, p = 2.74 × 10-8), and were more strongly linked to outcomes in diabetic participants (HR 0.64, p = 3.21 × 10-9 v. HR 0.90, p = 0.104, p value for interaction = 0.001). When analysis was performed at the level of individual metabolites, C16, C16:1, C18, and C18:1 had the greatest associations with both exercise capacity and outcomes, with higher levels associated with worse outcomes. Similar associations with time to the primary clinical outcome were not found in a control group of patients without HF from the CATHeterization GENetics (CATHGEN) study. CONCLUSIONS: LCAC biomarkers are associated with exercise status and clinical outcomes differentially in HF patients with and without DM. Impaired fatty acid substrate utilization and mitochondrial dysfunction both at the level of the skeletal muscle and the myocardium may explain the decreased exercise capacity, attenuated response to exercise training, and poor clinical outcomes seen in patients with HF and DM. Trial Registration clinicaltrials.gov Identifier: NCT00047437.

Proteomic mechanistic profile of patients with diabetes at risk of developing heart failure: insights from the HOMAGE trial.

BACKGROUND: Patients with diabetes mellitus (DM) are at increased risk of developing heart failure (HF). The "Heart OMics in AGEing" (HOMAGE) trial suggested that spironolactone had beneficial effect on fibrosis and cardiac remodelling in an at risk population, potentially slowing the progression towards HF. We compared the proteomic profile of patients with and without diabetes among patients at risk for HF in the HOMAGE trial. METHODS: Protein biomarkers (n = 276) from the Olink®Proseek-Multiplex cardiovascular and inflammation panels were measured in plasma collected at baseline and 9 months (or last visit) from HOMAGE trial participants including 217 patients with, and 310 without, diabetes. RESULTS: Twenty-one biomarkers were increased and five decreased in patients with diabetes compared to non-diabetics at baseline. The markers clustered mainly within inflammatory and proteolytic pathways, with granulin as the key-hub, as revealed by knowledge-induced network and subsequent gene enrichment analysis. Treatment with spironolactone in diabetic patients did not lead to large changes in biomarkers. The effects of spironolactone on NTproBNP, fibrosis biomarkers and echocardiographic measures of diastolic function were similar in patients with and without diabetes (all interaction analyses p > 0.05). CONCLUSIONS: Amongst patients at risk for HF, those with diabetes have higher plasma concentrations of proteins involved in inflammation and proteolysis. Diabetes does not influence the effects of spironolactone on the proteomic profile, and spironolactone produced anti-fibrotic, anti-remodelling, blood pressure and natriuretic peptide lowering effects regardless of diabetes status.  Trial registration NCT02556450.

Heart Failure in Type 2 Diabetes Mellitus.

Patients with diabetes mellitus have >2× the risk for developing heart failure (HF; HF with reduced ejection fraction and HF with preserved ejection fraction). Cardiovascular outcomes, hospitalization, and prognosis are worse for patients with diabetes mellitus relative to those without. Beyond the structural and functional changes that characterize diabetic cardiomyopathy, a complex underlying, and interrelated pathophysiology exists. Despite the success of many commonly used antihyperglycemic therapies to lower hyperglycemia in type 2 diabetes mellitus the high prevalence of HF persists. This, therefore, raises the possibility that additional factors beyond glycemia might contribute to the increased HF risk in diabetes mellitus. This review summarizes the state of knowledge about the impact of existing antihyperglycemic therapies on HF and discusses potential mechanisms for beneficial or deleterious effects. Second, we review currently approved pharmacological therapies for HF and review evidence that addresses their efficacy in the context of diabetes mellitus. Dysregulation of many cellular mechanisms in multiple models of diabetic cardiomyopathy and in human hearts have been described. These include oxidative stress, inflammation, endoplasmic reticulum stress, aberrant insulin signaling, accumulation of advanced glycated end-products, altered autophagy, changes in myocardial substrate metabolism and mitochondrial bioenergetics, lipotoxicity, and altered signal transduction such as GRK (g-protein receptor kinase) signaling, renin angiotensin aldosterone signaling and ß-2 adrenergic receptor signaling. These pathophysiological pathways might be amenable to pharmacological therapy to reduce the risk of HF in the context of type 2 diabetes mellitus. Successful targeting of these pathways could alter the prognosis and risk of HF beyond what is currently achieved using existing antihyperglycemic and HF therapeutics.

Zonisamide, an antiepileptic drug, alleviates diabetic cardiomyopathy by inhibiting endoplasmic reticulum stress.

Endoplasmic reticulum stress (ER stress) plays a key role in the development of cardiac hypertrophy and diabetic cardiomyopathy (DCM). Zonisamide (ZNS) was originally developed as an antiepileptic drug. Studies have shown that ZNS suppresses ER stress-induced neuronal cell damage in the experimental models of Parkinson's disease. Herein, we investigated whether ZNS improved DCM by attenuating ER stress-induced apoptosis. C57BL/6J mice were fed with high-fat diet (HFD) and intraperitoneally injected with low-dose streptozotocin (STZ) to induce type 2 diabetes mellitus (T2DM), and then treated with ZNS (40 mg·kg-1·d-1, i.g.) for 16 weeks. We showed that ZNS administration slightly ameliorated the blood glucose levels, but significantly alleviated diabetes-induced cardiac dysfunction and hypertrophy. Furthermore, ZNS administration significantly inhibited the Bax and caspase-3 activity, upregulated Bcl-2 activity, and decreased the proportion of TUNEL-positive cells in heart tissues. We analyzed the hallmarks of ER stress in heart tissues, and revealed that ZNS administration significantly decreased the protein levels of GRP78, XBP-1s, ATF6, PERK, ATF4, and CHOP, and elevated Hrd1 protein. In high glucose (HG)-treated primary cardiomyocytes, application of ZNS (3 µM) significantly alleviated HG-induced cardiomyocyte hypertrophy and apoptosis. ZNS application also suppressed activated ER stress in HG-treated cardiomyocytes. Moreover, preapplication of the specific ER stress inducer tunicamycin (10 ng/mL) eliminated the protective effects of ZNS against HG-induced cardiac hypertrophy and ER stress-mediated apoptosis. Our findings suggest that ZNS improves the cardiac diastolic function in diabetic mice and prevents T2DM-induced cardiac hypertrophy by attenuating ER stress-mediated apoptosis.

Muscle Damage in Systemic Sclerosis and CXCL10: The Potential Therapeutic Role of PDE5 Inhibition.

Skeletal muscle damage is a common clinical manifestation of systemic sclerosis (SSc). C-X-C chemokine ligand 10 (CXCL10) is involved in myopathy and cardiomyopathy development and is associated with a more severe SSc prognosis. Interestingly, the phosphodiesterase type 5 inhibitor (PDE5i) sildenafil reduces CXCL10 sera levels of patients with diabetic cardiomyopathy and in cardiomyocytes. Here, we analyzed the levels of CXCL10 in the sera of 116 SSc vs. 35 healthy subjects and explored differences in 17 SSc patients on stable treatment with sildenafil. CXCL10 sera levels were three-fold higher in SSc vs. healthy controls, independent of subset and antibody positivity. Sildenafil treatment was associated with lower CXCL10 sera levels. Serum CXCL10 strongly correlated with the clinical severity of muscle involvement and with creatine kinase (CK) serum concentration, suggesting a potential involvement in muscle damage in SSc. In vitro, sildenafil dose-dependently reduced CXCL10 release by activated myocytes and impaired cytokine-induced Signal transducer and activator of transcription 1 (STAT1), Nuclear factor-κB (NFκB) and c-Jun N-terminal kinase (JNK) phosphorylation. This was also seen in cardiomyocytes. Sildenafil-induced CXCL10 inhibition at the systemic and human muscle cell level supports the hypothesis that PDE5i could be a potential therapeutic therapy to prevent and treat muscle damage in SSc.

N-Acetyl Cysteine, Selenium, and Ascorbic Acid Rescue Diabetic Cardiac Hypertrophy via Mitochondrial-Associated Redox Regulators.

Metabolic disorders often lead to cardiac complications. Metabolic deregulations during diabetic conditions are linked to mitochondrial dysfunctions, which are the key contributing factors in cardiac hypertrophy. However, the underlying mechanisms involved in diabetes-induced cardiac hypertrophy are poorly understood. In the current study, we initially established a diabetic rat model by alloxan-administration, which was validated by peripheral glucose measurement. Diabetic rats displayed myocardial stiffness and fibrosis, changes in heart weight/body weight, heart weight/tibia length ratios, and enhanced size of myocytes, which altogether demonstrated the establishment of diabetic cardiac hypertrophy (DCH). Furthermore, we examined the expression of genes associated with mitochondrial signaling impairment. Our data show that the expression of PGC-1α, cytochrome c, MFN-2, and Drp-1 was deregulated. Mitochondrial-signaling impairment was further validated by redox-system dysregulation, which showed a significant increase in ROS and thiobarbituric acid reactive substances, both in serum and heart tissue, whereas the superoxide dismutase, catalase, and glutathione levels were decreased. Additionally, the expression levels of pro-apoptotic gene PUMA and stress marker GATA-4 genes were elevated, whereas ARC, PPARα, and Bcl-2 expression levels were decreased in the heart tissues of diabetic rats. Importantly, these alloxan-induced impairments were rescued by N-acetyl cysteine, ascorbic acid, and selenium treatment. This was demonstrated by the amelioration of myocardial stiffness, fibrosis, mitochondrial gene expression, lipid profile, restoration of myocyte size, reduced oxidative stress, and the activation of enzymes associated with antioxidant activities. Altogether, these data indicate that the improvement of mitochondrial dysfunction by protective agents such as N-acetyl cysteine, selenium, and ascorbic acid could rescue diabetes-associated cardiac complications, including DCH.

The association between bacterial infections and the risk of coronary heart disease in type 1 diabetes.

BACKGROUND: Diabetes increases the risk of infections and coronary heart disease (CHD). Whether infections increase the risk of CHD and how this applies to individuals with diabetes is unclear. OBJECTIVES: To investigate the association between bacterial infections and the risk of CHD in type 1 diabetes. METHODS: Individuals with type 1 diabetes (n = 3781) were recruited from the Finnish Diabetic Nephropathy Study (FinnDiane), a prospective follow-up study. CHD was defined as incident events: fatal or nonfatal myocardial infarction, coronary artery bypass surgery or percutaneous coronary intervention, identified through national hospital discharge register data. Infections were identified through national register data on all antibiotic purchases from outpatient care. Register data were available from 1 January 1995 to 31 December 2015. Bacterial lipopolysaccharide (LPS) activity was measured from serum samples at baseline. Data on traditional risk factors for CHD were collected during baseline and consecutive visits. RESULTS: Individuals with an incident CHD event (n = 370) had a higher mean number of antibiotic purchases per follow-up year compared to those without incident CHD (1.34 [95% CI: 1.16-1.52], versus 0.79 [0.76-0.82], P < 0.001), as well as higher levels of LPS activity (0.64 [0.60-0.67], versus 0.58 EU mL-1 [0.57-0.59], P < 0.001). In multivariable-adjusted Cox proportional hazards models, the mean number of antibiotic purchases per follow-up year was an independent risk factor for incident CHD (HR 1.21, 95% CI: 1.14-1.29, P < 0.0001). High LPS activity was a risk factor for incident CHD (HR 1.93 [1.34-2.78], P < 0.001) after adjusting for static confounders. CONCLUSION: Bacterial infections are associated with an increased risk of incident CHD in individuals with type 1 diabetes.

Fibroblast growth factor-23 is associated with imaging markers of diabetic cardiomyopathy and anti-diabetic therapeutics.

BACKGROUND: The biomarker fibroblast growth factor-23 (FGF-23) has been associated with increased cardiovascular morbidity and mortality in both patients with and without type 2 diabetes. The aim of this study was to evaluate the relationship between FGF-23 and cardiac structure, function and perfusion in patients with type 2 diabetes and normal or mildly impaired kidney function. Furthermore, to investigate the association between FGF-23, anti-diabetes therapy and the classic complications and risk factors associated with type 2 diabetes. METHODS: In this cross-sectional study, 246 patients with type 2 diabetes underwent echocardiography and advanced cardiac magnetic resonance imaging to assess left ventricular (LV) structure and function. In addition, myocardial blood flow (MBF) during rest and pharmacological stress (adenosine 140 µg/kg/min) were evaluated in 183 of the patients. Patients with eGFR < 60 ml/min/1.73 m2 were excluded. RESULTS: Median (Q1-Q3) FGF-23 was 74 (58-91) ng/L. Patients with FGF-23 above the median had lower MBF during stress (2.3 ± 0.9 vs. 2.7 ± 0.9 ml/min/g, P = 0.001) and lower overall myocardial perfusion reserve (MPR) (2.7 ± 0.8 vs. 3.3 ± 1.1, P < 0.001). LV mass (143 ± 40 vs. 138 ± 36 g, P = 0.04) and E/e* (8.5 ± 3.2 vs. 7.6 ± 2.7, P = 0.04) were higher in patients with FGF-23 above the median. In a linear model adjusted for age, sex, eGFR and hypertension, increasing FGF-23 was associated with decreased MPR (P < 0.01, R2 = 0.11) and increased E/e* (P < 0.01, R2 = 0.07). FGF-23 was lower in patients receiving glucagon like peptide-1 (GLP-1) analogues (71 (57-86) vs. 80 (60-98) ng/L, P = 0.01) than in those who did not receive GLP-1 analogues. CONCLUSIONS: In patients with type 2 diabetes and normal or mildly impaired kidney function, increased levels of FGF-23 are associated with impaired cardiac diastolic function and decreased MPR, caused by a decrease in maximal MBF during stress. Use of GLP-1 analogues is associated with decreased levels of FGF-23. Clinical trial registration https://www.clinicaltrials.gov . Unique identifier: NCT02684331. Date of registration: February 18, 2016.

Autophagy-dependent and -independent modulation of oxidative and organellar stress in the diabetic heart by glucose-lowering drugs.

Autophagy is a lysosome-dependent intracellular degradative pathway, which mediates the cellular adaptation to nutrient and oxygen depletion as well as to oxidative and endoplasmic reticulum stress. The molecular mechanisms that stimulate autophagy include the activation of energy deprivation sensors, sirtuin-1 (SIRT1) and adenosine monophosphate-activated protein kinase (AMPK). These enzymes not only promote organellar integrity directly, but they also enhance autophagic flux, which leads to the removal of dysfunctional mitochondria and peroxisomes. Type 2 diabetes is characterized by suppression of SIRT1 and AMPK signaling as well as an impairment of autophagy; these derangements contribute to an increase in oxidative stress and the development of cardiomyopathy. Antihyperglycemic drugs that signal through insulin may further suppress autophagy and worsen heart failure. In contrast, metformin and SGLT2 inhibitors activate SIRT1 and/or AMPK and promote autophagic flux to varying degrees in cardiomyocytes, which may explain their benefits in experimental cardiomyopathy. However, metformin and SGLT2 inhibitors differ meaningfully in the molecular mechanisms that underlie their effects on the heart. Whereas metformin primarily acts as an agonist of AMPK, SGLT2 inhibitors induce a fasting-like state that is accompanied by ketogenesis, a biomarker of enhanced SIRT1 signaling. Preferential SIRT1 activation may also explain the ability of SGLT2 inhibitors to stimulate erythropoiesis and reduce uric acid (a biomarker of oxidative stress)-effects that are not seen with metformin. Changes in both hematocrit and serum urate are the most important predictors of the ability of SGLT2 inhibitors to reduce the risk of cardiovascular death and hospitalization for heart failure in large-scale trials. Metformin and SGLT2 inhibitors may also differ in their ability to mitigate diabetes-related increases in intracellular sodium concentration and its adverse effects on mitochondrial functional integrity. Differences in the actions of SGLT2 inhibitors and metformin may reflect the distinctive molecular pathways that explain differences in the cardioprotective effects of these drugs.

Sustaining Circulating Regulatory T Cell Subset Contributes to the Therapeutic Effect of Paroxetine on Mice With Diabetic Cardiomyopathy.

BACKGROUND: G protein coupled receptor kinase 2 (GRK2) inhibitor, paroxetine, has been approved to ameliorate diabetic cardiomyopathy (DCM). GRK2 is also involved in regulating T cell functions; the potential modifications of paroxetine on the immune response to DCM is unclear.Methods and Results:DCM mouse was induced by high-fat diet (HFD) feeding. A remarkable reduction in the regulatory T (Treg) cell subset in DCM mouse was found by flow cytometry, with impaired cardiac function evaluated by echocardiography. The inhibited Treg differentiation was attributable to insulin chronic stimulation in a GRK2-PI3K-Akt signaling-dependent manner. The selective GRK2 inhibitor, paroxetine, rescued Treg differentiation in vitro and in vivo. Furthermore, heart function, as well as the activation of excitation-contraction coupling proteins such as phospholamban (PLB) and troponin I (TnI) was effectively promoted in paroxetine-treated DCM mice compared with vehicle-treated DCM mice. Blockade of FoxP3 expression sufficiently inhibited the proportion of Treg cells, abolished the protective effect of paroxetine on heart function as well as PLB and TnI activation in HFD-fed mice. Neither paroxetine nor carvedilol could effectively ameliorate the metabolic disorder of HFD mice. CONCLUSIONS: The impaired systolic heart function of DCM mice was effectively improved by paroxetine therapy, partially through restoring the population of circulating Treg cells by targeting the GRK2-PI3K-Akt pathway.

Acupuncture Reduces Hypertrophy and Cardiac Fibrosis, and Improves Heart Function in Mice with Diabetic Cardiomyopathy.

PURPOSE: To assess the effects of electro-acupuncture (EA) on glycemic control, myocardial inflammation, and the progression of diabetic cardiomyopathy in mice with type 2 diabetes. METHODS: Db/Db mice received EA at PC6+ST36 (DM-Acu), non-acupoint simulation (DM-Sham), or no treatment (DM). EA was applied for 30 min per day, 5 days a week for 4 weeks. Heart function was assessed by echocardiography. Myocardium was assessed by RT-PCR, immunoblotting, and histology. Serum TNF-α, IL-1α, IL-1ß, IL-6, and IL-8 were measured. RESULTS: DM-Acu, but not DM-Sham, reduced fasting blood glucose without affecting body weight. DM decreased systolic function. DM-Acu, but not DM-Sham, attenuated the decrease in systolic function. Heart weight was significantly smaller in the DM-Acu than in the DM and DM-Sham groups. Percent fibrosis and apoptosis were reduced in the DM-Acu, but not the DM-Sham, group. Serum levels of IL-1α, IL-1ß, IL-6, IL-8, ICAM-1, MCP-1, and TNF-α were significantly lower in the DM-Acu than in the DM or DM-Sham groups. Protein levels of P-Akt and P-AMPK and mRNA levels of phosphoinositide-3-kinase regulatory subunit 6 (PIK3r6) were significantly higher in the DM-Acu group. Myocardial mRNA and protein levels of insulin-like growth factor 1 receptor (IGF1R) were significantly lower in the DM and DM-Sham groups compared with the DM-Acu group. CONCLUSIONS: EA reduced serum glucose; prevented DM-induced hypertrophy and deterioration of systolic function, inflammation, and fibrosis; and restored IGF1R, P-Akt, and P-AMPK levels in mice with type 2 diabetes mellitus.

Galectin-3 mediates high-glucose-induced cardiomyocyte injury by the NADPH oxidase/reactive oxygen species pathway.

Galectin-3 is a member of the ß-galactoside-binding lectin family taking part in the regulation of inflammation, angiogenesis, and fibrosis. This study was designed to study the improved effect of galectin-3 inhibition on diabetic cardiomyopathy (DCM). Sprague-Dawley rats were randomized into the control, DCM, and DCM + modified citrus pectin (MCP) (a galectin-3 pharmacological inhibitor) groups. After 8 weeks, streptozotocin-induced DCM led to high blood glucose level, oxidative stress, cardiac injury, and dysfunction accompanied by suppressed body mass. On the contrary, MCP (100 mg·kg-1·day-1) administration improved body mass and blood glucose level and attenuated cardiac injury and dysfunction in DCM rats. Additionally, MCP attenuated pathological changes in plasma and myocardial tissue markers of oxidative stress, such as hydrogen peroxide and malonyldialdehyde, although it did not change superoxide dismutase activities, which were decreased in the DCM group. The levels of oxidative stress associated proteins evaluated by Western blot, such as p67phox and NADPH oxidase 4, were obviously increased in the DCM group, while they were reversed by MCP treatment. Therefore, galectin-3-mediated high-glucose-induced cardiomyocyte injury and galectin-3 inhibition attenuated DCM by suppressing NADPH oxidase. These findings suggested that galectin-3 could be a potential target for treatment of patients with DCM.

Therapeutic potential of vitamin D in AGE/RAGE-related cardiovascular diseases.

Cardiovascular diseases (CVDs) are among the leading threats to human health. The advanced glycation end product (AGE) and receptor for AGE (RAGE) signaling pathway regulates the pathogenesis of CVDs, through its effects on arterial stiffness, atherosclerosis, mitochondrial dysfunction, oxidative stress, calcium homeostasis, and cytoskeletal function. Targeting the AGE/RAGE pathway is a potential therapeutic strategy for ameliorating CVDs. Vitamin D has several beneficial effects on the cardiovascular system. Experimental findings have shown that vitamin D regulates AGE/RAGE signaling and its downstream effects. This article provides a comprehensive review of the mechanistic insights into AGE/RAGE involvement in CVDs and the modulation of the AGE/RAGE signaling pathways by vitamin D.

Sex-specific prevalence of coronary heart disease among Tehranian adult population across different glycemic status: Tehran lipid and glucose study, 2008-2011.

BACKGROUND: Coronary heart disease (CHD) is one of the leading causes of death. Alarmingly Iranian populations had a high rank of CHD worldwide. The current study aimed to assess the prevalence of CHD across different glycemic categories. METHODS: This study was conducted on 7718 Tehranian participants (Men = 3427) aged ≥30 years from 2008 to 2011. They were categorized based on glycemic status. The prevalence of CHD was calculated in each group separately. CHD was defined as hospital records adjudicated by an outcome committee. The association of different glycemic categories with CHD was calculated using multivariate logistic regression, compared with normal fasting glucose /normal glucose tolerance (NFG/NGT) group as reference. RESULTS: The age-standardized prevalence of isolated impaired fasting glucose (iIFG), isolated impaired glucose tolerance (iIGT), both impaired fasting glucose and impaired glucose tolerance (IFG/IGT), newly diagnosed diabetes mellitus (NDM), and known diabetes mellitus (KDM) were 14.30% [95% confidence interval (CI): 13.50-15.09], 4.81% [4.32-5.29], 5.19% [4.71-5.67], 5.79% [5.29-6.28] and 7.72% [7.17-8.27], respectively. Among a total of 750 individuals diagnosed as cases of CHD (398 in men), 117 (15.6%), 453 (60.4%), and 317 (42.3%) individuals had a history of myocardial infarction (MI), cardiac procedure, and unstable angina, respectively. The age-standardized prevalence of CHD for the Tehranian population was 7.71% [7.18-8.24] in the total population, 8.62 [7.81-9.44] in men and 7.19 [6.46-7.93] in women. Moreover, among diabetic participants, the age-standardized prevalence of CHD was 13.10 [9.83-16.38] in men and 10.67 [8.90-12.44] in women, significantly higher than corresponding values for NFG/NGT and prediabetic groups. Across six levels of glycemic status, CHD was associated with IFG/IGT [odds ratio (OR) and 95% CI: 1.38 (1.01-1.89)], NDM [1.83 (1.40-2.41)], and KDM [2.83 (2.26-3.55)] groups, in the age- and sex-adjusted model. Furthermore, in the full-adjusted model, only NDM and KDM status remained to be associated with the presence of CHD by ORs of 1.40 (1.06-1.86) for NDM and 1.91 (1.51-2.43) for KDM. CONCLUSION: The high prevalence of CHD, especially among diabetic populations, necessitates the urgent implementation of behavioral interventions in the Tehranian population, according to evidence-based guidelines for the clinical management of diabetic patients.

Clinical aspects of heart failure in individuals with diabetes.

Heart failure (HF) is an important comorbidity in individuals with diabetes. Most commonly, the condition is secondary to ischaemia and hypertension. Diabetic cardiomyopathy is becoming increasingly recognised as a cause of HF and blood glucose control plays a pivotal role in the prevention and treatment of HF. Since the US Food and Drug Administration regulatory guidance in 2008, new glucose-lowering agents are evaluated routinely by cardiovascular outcome trials. These trials offer a wealth of knowledge and allow better understanding of the risks and benefits of contemporary diabetes medications. In this review, we will focus on the risks of HF with emerging glucose-lowering therapies and the safety of these medications in patients with established HF. We will summarise the guidance that is available for the treatment algorithm of diabetes in those with HF and highlight future areas of research.

Attenuation of diabetic cardiomyopathy by relying on kirenol to suppress inflammation in a diabetic rat model.

Diabetic cardiomyopathy is characterized by diabetes-induced myocardial abnormalities, accompanied by inflammatory response and alterations in inflammation-related signalling pathways. Kirenol, isolated from Herba Siegesbeckiae, has potent anti-inflammatory properties. In this study, we aimed to investigate the cardioprotective effect of kirenol against DCM and underlying the potential mechanisms in a type 2 diabetes mellitus model. Kirenol treatment significantly decreased high glucose-induced cardiofibroblasts proliferation and increased the cardiomyocytes viability, prevented the loss of mitochondrial membrane potential and further attenuated cardiomyocytes apoptosis, accompanied by a reduction in apoptosis-related protein expression. Kirenol gavage could affect the expression of pro-inflammatory cytokines in a dose-dependent manner but not lower lipid profiles, and only decrease fasting plasma glucose, fasting plasma insulin and mean HbA1c levels in high-dose kirenol-treated group at some time-points. Left ventricular dysfunction, hypertrophy, fibrosis and cell apoptosis, as structural and functional abnormalities, were ameliorated by kirenol administration. Moreover, in diabetic hearts, oral kirenol significantly attenuated activation of mitogen-activated protein kinase subfamily and nuclear translocation of NF-κB and Smad2/3 and decreased phosphorylation of IκBα and both fibrosis-related and apoptosis-related proteins. In an Electrophoretic mobility shift assay, the binding activities of NF-κB, Smad3/4, SP1 and AP-1 in the nucleus of diabetic myocardium were significantly down-regulated by kirenol treatment. Additionally, high dose significantly enhanced myocardial Akt phosphorylation without intraperitoneal injection of insulin. Kirenol may have potent cardioprotective effects on treating for the established diabetic cardiomyopathy, which involves the inhibition of inflammation and fibrosis-related signalling pathways and is independent of lowering hyperglycaemia, hyperinsulinemia and lipid profiles.