Cardiac Glucolipotoxicity and Cardiovascular Outcomes

The role of myocardial energy metabolism perturbations in diabetic cardiomyopathy: from the perspective of novel protein post-translational modifications

Diabetic cardiomyopathy (DbCM), a significant chronic complication of diabetes, manifests as myocardial hypertrophy, fibrosis, and other pathological alterations that substantially impact cardiac function and elevate the risk of cardiovascular diseases and patient mortality. Myocardial energy metabolism disturbances in DbCM, encompassing glucose, fatty acid, ketone body and lactate metabolism, are crucial factors that contribute to the progression of DbCM. In recent years, novel protein post-translational modifications (PTMs) such as lactylation, β-hydroxybutyrylation, and succinylation have been demonstrated to be intimately associated with the myocardial energy metabolism process, and in conjunction with acetylation, they participate in the regulation of protein activity and gene expression activity in cardiomyocytes. This review examines the epigenetic pathogenesis of DbCM, primarily focusing on myocardial energy metabolism perturbations and novel PTMs associated with them. It provides a detailed analysis of the mechanisms of these novel PTMs in DbCM to enhance the understanding of DbCM pathophysiology and establish a theoretical foundation for the development of new treatment strategies for DbCM.

Remodeling of the Intracardiac Ganglia During the Development of Cardiovascular Autonomic Dysfunction in Type 2 Diabetes: Molecular Mechanisms and Therapeutics

Type 2 diabetes mellitus (T2DM) is one of the most significant health issues worldwide, with associated healthcare costs estimated to surpass USD 1054 billion by 2045. The leading cause of death in T2DM patients is the development of cardiovascular disease (CVD). In the early stages of T2DM, patients develop cardiovascular autonomic dysfunction due to the withdrawal of cardiac parasympathetic activity. Diminished cardiac parasympathetic tone can lead to cardiac arrhythmia-related sudden cardiac death, which accounts for 50% of CVD-related deaths in T2DM patients. Regulation of cardiovascular parasympathetic activity is integrated by neural circuitry at multiple levels including afferent, central, and efferent components. Efferent control of cardiac parasympathetic autonomic tone is mediated through the activity of preganglionic parasympathetic neurons located in the cardiac extensions of the vagus nerve that signals to postganglionic parasympathetic neurons located in the intracardiac ganglia (ICG) on the heart. Postganglionic parasympathetic neurons exert local control on the heart, independent of higher brain centers, through the release of neurotransmitters, such as acetylcholine. Structural and functional alterations in cardiac parasympathetic postganglionic neurons contribute to the withdrawal of cardiac parasympathetic tone, resulting in arrhythmogenesis and sudden cardiac death. This review provides an overview of the remodeling of parasympathetic postganglionic neurons in the ICG, and potential mechanisms contributing to the withdrawal of cardiac parasympathetic tone, ventricular arrhythmogenesis, and sudden cardiac death in T2DM. Improving cardiac parasympathetic tone could be a therapeutic avenue to reduce malignant ventricular arrhythmia and sudden cardiac death, increasing both the lifespan and improving quality of life of T2DM patients.

Elucidating the interplay of PPAR gamma inhibition and energy demand in adriamycin-induced cardiomyopathy: In Vitro and In Vivo perspective

Adriamycin is an anticancer anthracycline drug that inhibits the progression of topoisomerase II activity and causes apoptosis. The effective clinical application of the drug is very much limited by its adverse drug reactions on various tissues. Most importantly, Adriamycin causes cardiomyopathy, one of the life-threatening complications of the drug. Altered expression of PPARγ in adipocytes inhibited the glucose and fatty acids uptake by down regulating GLUT4 and CD36 expression and causes cardiotoxicity. Therefore, the influence of Adriamycin in cardiac ailments was investigated in vivo and in vitro. Adriamycin treated rats showed altered ECG profile, arrhythmic heartbeat with the elevated levels of CRP and LDH. Dysregulated lipid profiles with elevated levels of cholesterol and triglycerides were also observed. Possibilities of cardiac problems due to cardiomyopathy were analyzed through histopathology. Adriamycin treated rats showed no signs for atheromatous plaque formation in aorta but disorganized cardiomyocytes with myofibrillar loss and inflammation in heart tissue, indicative of cardiomyopathy. Reduced levels of antioxidant enzymes confirmed the incidence of oxidative stress. Adriamycin treatment significantly reduced glucose and insulin levels, creating energy demand due to decreased glucose and insulin levels with increased fatty acid accumulation, ultimately resulting in oxidative stress mediated cardiomyopathy. Since PPARs play a vital role in regulating oxidative stress, the effect of Adriamycin on PPARγ was analyzed by western blot. Adriamycin downregulated PPARγ in a dose-dependent manner in H9C2 cells in vitro. Overall, our study suggests that Adriamycin alters glucose and lipid metabolism via PPARγ inhibition that leads to oxidative stress and cardiomyopathy that necessitates a different therapeutic approach.

When the liver is in poor condition, so is the heart - cardiac remodelling in MASH mouse models

Metabolic dysfunction-associated steatohepatitis (MASH) confers a risk for cardiovascular diseases in patients. Animal models may help exploring the mechanisms linking liver and heart diseases. Hence, we explored the cardiac phenotype in two MASH mouse models: foz/foz mice fed a high-fat diet (HFD) for 24 or 60 weeks and C57BL/6J mice fed a high-fat-, high-cholesterol-, and high-fructose diet for 60 weeks. Angiotensin II (AngII) was used as an additional cardiovascular stressor for 4 weeks in 10 weeks HFD-fed foz/foz mice. Foz/foz mice with fibrosing MASH developed cardiac hypertrophy with adverse cardiac remodelling not seen in WT similarly fed the HFD. AngII caused hypertension and up-regulated the expression of genes contributing to pathological cardiac hypertrophy (Nppa, Myh7) more severely so in foz/foz mice than in controls. After 60 weeks of HFD, while liver disease had progressed to burn-out non steatotic MASH with hepatocellular carcinoma in 50% of the animals, the cardiomyopathy did not. In an independent model (C57BL/6J mice fed a fat-, cholesterol- and fructose-rich diet), moderate fibrosing MASH is associated with cardiac fibrosis and dysregulation of genes involved in pathological remodelling (Col1a1, Col3a1, Vim, Myh6, Slc2a1). Thus, animals with MASH present consistent adverse structural changes in the heart with no patent alteration of cardiac function even when stressed with exogenous AngII. Liver disease, and likely not overfeeding or aging alone, is associated with this cardiac phenotype. Our findings support foz/foz mice as suitable for studying links between MASH and heart structural changes ahead of heart failure.

Crucial Interactions between Altered Plasma Trace Elements and Fatty Acids Unbalance Ratio to Management of Systemic Arterial Hypertension in Diabetic Patients: Focus on Endothelial Dysfunction

The coexistence of SAH with T2DM is a common comorbidity. In this study, we investigated the link between altered plasma antioxidant trace elements (ATE: manganese, selenium, zinc, and copper) and fatty acids ratio (FAR: polyunsaturated/saturated) imbalance as transition biomarkers between vascular pathology (SAH) to metabolic pathology (T2DM). Our data revealed strong correlation between plasma ATE and FAR profile, which is modified during SAH-T2DM association compared to the healthy group. This relationship is mediated by lipotoxicity (simultaneously prominent visceral adipose tissue lipolysis, significant flow of non-esterified free fatty acids release, TG-Chol-dyslipidemia, high association of total SFA, palmitic acid, arachidonic acid, and PUFA ω6/PUFA ω3; drop in tandem of PUFA/SFA and EPA + DHA); oxidative stress (lipid peroxidation confirmed by TAS depletion and MDA rise, concurrent drop of Zn/Cu-SOD, GPx, GSH, Se, Zn, Se/Mn, Zn/Cu; concomitant enhancement of Cu, Mn, and Fe); endothelial dysfunction (endotheline-1 increase); athero-thrombogenesis risk (concomitant rise of ApoB100/ApoA1, Ox-LDL, tHcy, and Lp(a)), and inflammation (higher of Hs-CRP, fibrinogen and ferritin). Our study opens to new therapeutic targets and to better dietary management, such as to establishing dietary ATE and PUFA ω6/PUFA ω3 or PUFA/SFA reference values for atherosclerotic risk prevention in hypertensive/diabetic patients.

The Protective Effects of Eicosapentaenoic Acid for Stress-induced Accelerated Senescence in Vascular Endothelial Cells

Background: Eicosapentaenoic acid (EPA) is an omega-3 fatty acid that protects against cardiovascular diseases in patients with hypertriglyceridemia and may have pleotropic effects beyond lowering triglycerides. Many degenerative diseases, such as atherosclerosis and diabetes, are related to cellular senescence as a pathophysiological mechanism. We aimed to examine whether EPA could protect vascular endothelial cells under stress conditions against stress-induced accelerated senescence (SIAS). Methods: Cultured human umbilical vein endothelial cells (HUVECs) were exposed to H2O2 as oxidative stress and a high glucose concentration with palmitate as a glucolipotoxic condition. Changes in cell viability, apoptosis, lactate dehydrogenase release, and cell cycle analysis were measured by cell counting kit-8 assay, annexin V/ propidium iodide staining, and enzyme-linked immunosorbent assay, respectively. EPA was applied in stress conditions. The degree of senescence was measured by senescence-associated beta-galactosidase staining and p16 staining using immunofluorescence. Apoptosis and cellular senescence-related proteins were measured by Western blotting. Results: Cultured HUVECs under oxidative and glucolipotoxic stresses revealed accelerated senescence and increased apoptosis. These changes were markedly reversed by EPA administration, and the expressions of apoptosis and cellular senescence-related proteins were reversed by EPA treatment. Conclusion: EPA effectively protects HUVECs against SIAS, which may be one of its pleotrophic effects.

The pattern of dyslipidemia among Somali type 2 diabetic patients: a cross-sectional study

BACKGROUND

Diabetes mellitus (DM) is a major public health concern. This study aims to determine frequency, pattern, and potential determinants of dyslipidemia among adults with type 2 DM (T2DM) at Somalia's only diabetes outpatient clinic.

METHODS

Five hundred twenty-nine consecutive patients with T2DM who applied to our outpatient clinic between January 2020 and June 2020 were included in this cross-sectional hospital-based study. Demographic characteristics of participants, including lipid panel, were extracted from the registry system. Correlation analysis was performed between lipid profile and related parameters. Multivariate binary logistic regression models were used to identify independent determinants of dyslipidemia for further analysis.

RESULTS

The overall population's mean age was 51.9 ± 12.2 years, with 177 (33.5%) males. Total and atherogenic dyslipidemias were found in 92.8% and 24.8%, respectively. The most common isolated pattern of dyslipidemia was high non-high-density lipoprotein cholesterol (non-HDL-C) (82.8%), followed by high low-density lipoprotein cholesterol (LDL-C) (72.6%), high total cholesterol (TC) (54.3%), and low HDL-C (48.3%). Females were found to have a higher prevalence of high TC (63.4% vs. 54.2%, p = 0.043) and lower HDL-C (57.4% vs. 46.3%, p = 0.016). High LDL-C with low HDL-C was the most common pattern among combined type dyslipidemias (18.1%), followed by high LDL-C with high triglyceride (TG) (17.8%), as well as low TG with low HDL-C (3.6%). Females had a higher proportion of high LDL-C with low HDL-C than males (20.3% vs. 13.6%, p = 0.036). Age, gender, body mass index, central obesity, spot urinary proteinuria, fasting blood glucose, poor glycemic control, creatinine, and Hs-CRP were all associated with different dyslipidemia patterns in multivariate logistic regression analyses.

CONCLUSIONS

We found that the prevalence of dyslipidemia, especially atherogenic patterns, was extremely high among Somali T2DM patients. An enhanced health policy should, therefore, be established to detect, treat and prevent dyslipidemia.

Palmitate Induces Mitochondrial Energy Metabolism Disorder and Cellular Damage via the PPAR Signaling Pathway in Diabetic Cardiomyopathy

PURPOSE

To establish an in vitro lipotoxicity model with mouse cardiomyocytes (MCMs) and investigate the molecular mechanism of the peroxisome proliferator-activated receptors (PPAR) signaling on mitochondrial energy metabolism disorder and cellular injury in diabetic cardiomyopathy (DCM).

METHODS

Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed on the differentially expressed genes (DEGs) of DCM. CCK-8 method was used to detect the proliferation inhibition effect of palmitate (PA) on MCMs. Oil red O staining and mRNA levels of CD36 were used to verify intracellular lipid accumulation. DCFH-DA method was used to determine the content of intracellular reactive oxygen species (ROS), and ATP levels were detected by the ATP Detection Kit. Transmission electron microscope (TEM) was used to observe the mitochondrial structure. Western blot was used to detect the expression levels of PPARα, PPARγ, P-mTOR, mTOR, PGC-1α, UCP2, and BNP. In addition, the expression of PPARγ was also detected by cellular immunofluorescence staining. BNP levels were detected by qRT-PCR and the ELISA Kit.

RESULTS

KEGG pathway analysis combined with GO analysis has shown that PPAR signaling played a significant regulatory role in mitochondrial biogenesis and fatty acid metabolism in DCM. Then, MCMs stimulated with PA for 24 h were selected as an in vitro lipotoxicity model. PA decreased cell viability, cell membrane shrinkage, and lipid accumulation. Meanwhile, PA-induced increase in cellular ROS led to ATP generation reduction and mitochondrial damage. Furthermore, the expression levels of p-mTOR- PPARα/γ were decreased, and the expressions of PGC-1α and UCP2 were increased. The levels of BNP were elevated, demonstrating PA impaired cardiomyocytes.

CONCLUSION

Mitochondrial energy metabolism obstacle and cell injury appeared in cardiac lipotoxicity of DCM, associated with lipid accumulation and increased ROS, indicating a crosstalk with the PPAR pathway mediated mechanism.

Alleviation of glucolipotoxicity-incurred cardiomyocyte dysfunction by Z-ligustilide involves in the suppression of oxidative insult, inflammation and fibrosis

Diabetes mellitus ranks as a major risk cause for disability and death around the world due to its complications, especially diabetic cardiomyopathy (DCM). Glucolipotoxicity is one of the critical causal factors of DCM. Recent finding confirms the beneficial roles of Z-ligustilide in diabetes mellitus. Nevertheless, its efficacy in DCM remains elusive. Here, Z-ligustilide elevated high glucose/high palmitic acid (HG/P)-inhibited cell viability and attenuated HG/P-induced cell apoptosis, caspase-3 activity, pro-apoptotic Bax and anti-apoptotic Bcl-2 protein expression. Furthermore, Z-ligustilide alleviated HG/P-evoked oxidative damage by decreasing HG/P-induced elevation in ROS, lactate dehydrogenase (LDH) and malondialdehyde (MDA) leakage, but increasing antioxidant enzyme-superoxide dismutase (SOD) and glutathione (GSH) levels suppressed by HG/P. Concomitantly, Z-ligustilide attenuated HG/P-induced cardiomyocyte fibrosis by increasing MMP-14 expression and diminishing HG/P-enhanced fibrotic protein expression, including collagen I, collagen II and TGF-β. Mechanistically, Z-ligustilide offset the adverse effects of HG/P on the activation of the AMPK/GSK-3β/Nrf2 pathway. Importantly, blocking the AMPK signaling overturned the protective efficacy of Z-ligustilide against HG/P-induced cardiomyocyte oxidative damage, inflammation and fibrosis. Together, these findings highlight that Z-ligustilide may alleviate glucolipotoxicity-induced cardiomyocyte dysfunction by regulating cell oxidative injury, inflammation and fibrosis via the AMPK/GSK-3β/Nrf2 pathway. Consequently, Z-ligustilide may represent a promising therapeutic agent against DCM by restoring cardiomyocyte dysfunction.

Effect of Admission Hyperglycemia on Short-Term Prognosis of Patients with Non-ST Elevation Acute Coronary Syndrome without Diabetes Mellitus

OBJECTIVE

To evaluate the effect of admission hyperglycemia on the short-term prognosis of patients with non-ST elevation acute coronary syndrome (NSTE-ACS) without diabetes mellitus.

METHODS

The clinical data of 498 patients with NSTE-ACS admitted to the Department of Cardiology of the First Affiliated Hospital of Henan University of Science and Technology between March 2018 and November 2020 were analyzed. Based on the blood glucose (BG) level at admission, patients were divided into three groups: A (BG < 7.8 mmol/L), B (7.8 mmol/L ≤ BG < 11.1 mmol/L), and C (BG ≥ 11.1 mmol/L). The clinical data of the three groups were compared.

RESULTS

There was no significant difference between the three groups in terms of age, sex, hypertension, hyperlipidemia, smoking, and history of myocardial infarction (p > 0.05). However, there were significant differences in the incidences of multivessel disease, renal insufficiency, pump failure, and emergency percutaneous coronary intervention, and levels of high-sensitivity C-reactive protein, cardiac troponin T, and creatine kinase isoenzyme MB among the three groups (p < 0.05 for all). The incidences of severe pump failure, malignant arrhythmias, and death were significantly higher in groups B and C compared to group A (p < 0.05). Additionally, the incidences of severe pump failure, malignant arrhythmias, and death were significantly higher in group C compared to group B (p < 0.05). Multivariate logistic regression analysis showed that hyperglycemia, renal insufficiency, Killip grade III/IV, and age were risk factors of in-hospital death.

CONCLUSION

Hyperglycemia at admission is a risk factor for adverse in-hospital clinical outcomes in patients with NSTE-ACS.

Age and Sex Influence Mitochondria and Cardiac Health in Offspring Exposed to Maternal Glucolipotoxicity

Infants of diabetic mothers are at risk of cardiomyopathy at birth and myocardial infarction in adulthood, but prevention is hindered because mechanisms remain unknown. We previously showed that maternal glucolipotoxicity increases the risk of cardiomyopathy and mortality in newborn rats through fuel-mediated mitochondrial dysfunction. Here we demonstrate ongoing cardiometabolic consequences by cross-fostering and following echocardiography, cardiomyocyte bioenergetics, mitochondria-mediated turnover, and cell death following metabolic stress in aged adults. Like humans, cardiac function improves by weaning with no apparent differences in early adulthood but declines again in aged diabetes-exposed offspring. This is preceded by impaired oxidative phosphorylation, exaggerated age-related increase in mitochondrial number, and higher oxygen consumption. Prenatally exposed male cardiomyocytes have more mitolysosomes indicating high baseline turnover; when exposed to metabolic stress, mitophagy cannot increase and cardiomyocytes have faster mitochondrial membrane potential loss and mitochondria-mediated cell death. Details highlight age- and sex-specific roles of mitochondria in developmentally programmed adult heart disease.

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Fetal exposures disrupt mitochondria, bioenergetics, & cardiac function at birth

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First, bioenergetics & function improve until greater reliance on OXPHOS with age

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At 6MO, poor respiration incites biogenesis & mitophagy, and then functional decline

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Fetal exposures cause faster mitochondria-mediated cell death in aged adult hearts

Dyslipidemia: A Trigger for Coronary Heart Disease in Romanian Patients with Diabetes

Previous studies have reported age and gender disparities in the occurrence and therapeutic approach of dyslipidemia and (or) coronary heart disease (CHD) in patients with type 2 diabetes mellitus (T2DM). We aimed to investigate these differences in Romanian patients with T2DM. A cross-sectional, observational, retrospective study was conducted using the medical records of T2DM patients who attended the outpatient facility of the Internal Medicine Clinic of the Clinical Emergency Hospital of Bucharest, Romania for routine check-ups in a six-month period. We analyzed the records of 217 diabetic patients (mean age 69 ± 11 years; 51.15% women). We found no significant gender differences in the occurrence of dyslipidemia, CHD or CHD + dyslipidemia or in terms of statin prescription. However; patients aged 65 years or older were significantly more affected by dyslipidemia, CHD or CHD + dyslipidemia, versus subjects aged <65 years. Further, they were more likely to be prescribed statin therapy (p < 0.0001 for all). Statins were prescribed to 67.24% of the patients with dyslipidemia; 61.01% of the subjects with CHD; and to 91.48% of the patients who had both conditions. e recorded no gender differences in the occurrence of CHD and (or) dyslipidemia in Romanian T2DM patients. Patients aged 65 years or older had a higher prevalence of CHD and/or dyslipidemia, and were more likely to be prescribed statins, versus younger counterparts. However, many T2DM patients with CHD and (or) dyslipidemia were undertreated: Nearly 33% of the subjects with dyslipidemia, and nearly 40% of the ones with CHD were not prescribed statins.

High Fat Programming and Cardiovascular Disease

Programming is triggered through events during critical developmental phases that alter offspring health outcomes. High fat programming is defined as the maintenance on a high fat diet during fetal and/or early postnatal life that induces metabolic and physiological alterations that compromise health. The maternal nutritional status, including the dietary fatty acid composition, during gestation and/or lactation, are key determinants of fetal and postnatal development. A maternal high fat diet and obesity during gestation compromises the maternal metabolic state and, through high fat programming, presents an unfavorable intrauterine milieu for fetal growth and development thereby conferring adverse cardiac outcomes to offspring. Stressors on the heart, such as a maternal high fat diet and obesity, alter the expression of cardiac-specific factors that alter cardiac structure and function. The proper nutritional balance, including the fatty acid balance, particularly during developmental windows, are critical for maintaining cardiac structure, preserving cardiac function and enhancing the cardiac response to metabolic challenges.