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

Research Progress of Maternal Metabolism on Cardiac Development and Function in Offspring

The developmental origin of health and disease (DOHaD) hypothesis refers to the adverse effects of suboptimal developmental environments during embryonic and early fetal stages on the long-term health of offspring. Intrauterine metabolic perturbations can profoundly impact organogenesis in offspring, particularly affecting cardiac development and giving rise to potential structural and functional abnormalities. In this discussion, we contemplate the existing understanding regarding the impact of maternal metabolic disorders, such as obesity, diabetes, or undernutrition, on the developmental and functional aspects of the offspring's heart. This influence has the potential to contribute to the susceptibility of offspring to cardiovascular health issues. Alteration in the nutritional milieu can influence mitochondrial function in the developing hearts of offspring, while also serving as signaling molecules that directly modulate gene expression. Moreover, metabolic disorders can exert influence on cardiac development-related genes epigenetically through DNA methylation, levels of histone modifications, microRNA expression, and other factors. However, the comprehensive understanding of the mechanistic underpinnings of these phenomena remains incomplete. Further investigations in this domain hold profound clinical significance, as they can contribute to the enhancement of public health and the prevention of cardiovascular diseases.

Long-term outcomes and potential mechanisms of offspring exposed to intrauterine hyperglycemia

Diabetes mellitus during pregnancy, which can be classified into pregestational diabetes and gestational diabetes, has become much more prevalent worldwide. Maternal diabetes fosters an intrauterine abnormal environment for fetus, which not only influences pregnancy outcomes, but also leads to fetal anomaly and development of diseases in later life, such as metabolic and cardiovascular diseases, neuropsychiatric outcomes, reproduction malformation, and immune dysfunction. The underlying mechanisms are comprehensive and ambiguous, which mainly focus on microbiota, inflammation, reactive oxygen species, cell viability, and epigenetics. This review concluded with the influence of intrauterine hyperglycemia on fetal structure development and organ function on later life and outlined potential mechanisms that underpin the development of diseases in adulthood. Maternal diabetes leaves an effect that continues generations after generations through gametes, thus more attention should be paid to the prevention and treatment of diabetes to rescue the pathological attacks of maternal diabetes from the offspring.

Impact of Prenatal Exposure to Maternal Diabetes and High-Fat Diet on Postnatal Myocardial Ketone Body Metabolism in Rats

Infants exposed to diabetic pregnancy are at higher risk of cardiomyopathy at birth and early onset cardiovascular disease (CVD) as adults. Using a rat model, we showed how fetal exposure to maternal diabetes causes cardiac disease through fuel-mediated mitochondrial dysfunction, and that a maternal high-fat diet (HFD) exaggerates the risk. Diabetic pregnancy increases circulating maternal ketones which can have a cardioprotective effect, but whether diabetes-mediated complex I dysfunction impairs myocardial metabolism of ketones postnatally remains unknown. The objective of this study was to determine whether neonatal rat cardiomyocytes (NRCM) from diabetes- and HFD-exposed offspring oxidize ketones as an alternative fuel source. To test our hypothesis, we developed a novel ketone stress test (KST) using extracellular flux analyses to compare real-time ß-hydroxybutyrate (βHOB) metabolism in NRCM. We also compared myocardial expression of genes responsible for ketone and lipid metabolism. NRCM had a dose-dependent increase in respiration with increasing concentrations of βHOB, demonstrating that both control and combination exposed NRCM can metabolize ketones postnatally. Ketone treatment also enhanced the glycolytic capacity of combination exposed NRCM with a dose-dependent increase in the glucose-mediated proton efflux rate (PER) from CO2 (aerobic glycolysis) alongside a decreased reliance on PER from lactate (anaerobic glycolysis). Expression of genes responsible for ketone body metabolism was higher in combination exposed males. Findings demonstrate that myocardial ketone body metabolism is preserved and improves fuel flexibility in NRCM from diabetes- and HFD-exposed offspring, which suggests that ketones might serve a protective role in neonatal cardiomyopathy due to maternal diabetes.

Developmental programming of mitochondrial substrate metabolism in skeletal muscle of adult sheep by cortisol exposure before birth

Prenatal glucocorticoid overexposure causes adult metabolic dysfunction in several species but its effects on adult mitochondrial function remain largely unknown. Using respirometry, this study examined mitochondrial substrate metabolism of fetal and adult ovine biceps femoris (BF) and semitendinosus (ST) muscles after cortisol infusion before birth. Physiological increases in fetal cortisol concentrations pre-term induced muscle- and substrate-specific changes in mitochondrial oxidative phosphorylation capacity in adulthood. These changes were accompanied by muscle-specific alterations in protein content, fibre composition and abundance of the mitochondrial electron transfer system (ETS) complexes. In adult ST, respiration using palmitoyl-carnitine and malate was increased after fetal cortisol treatment but not with other substrate combinations. There were also significant increases in protein content and reductions in the abundance of all four ETS complexes, but not ATP synthase, in the ST of adults receiving cortisol prenatally. In adult BF, intrauterine cortisol treatment had no effect on protein content, respiratory rates, ETS complex abundances or ATP synthase. Activity of citrate synthase, a marker of mitochondrial content, was unaffected by intrauterine treatment in both adult muscles. In the ST but not BF, respiratory rates using all substrate combinations were significantly lower in the adults than fetuses, predominantly in the saline-infused controls. The ontogenic and cortisol-induced changes in mitochondrial function were, therefore, more pronounced in the ST than BF muscle. Collectively, the results show that fetal cortisol overexposure programmes mitochondrial substrate metabolism in specific adult muscles with potential consequences for adult metabolism and energetics.

The sex-dependent response to psychosocial stress and ischaemic heart disease

Stress is an important risk factor for modern chronic diseases, with distinct influences in males and females. The sex specificity of the mammalian stress response contributes to the sex-dependent development and impacts of coronary artery disease (CAD). Compared to men, women appear to have greater susceptibility to chronic forms of psychosocial stress, extending beyond an increased incidence of mood disorders to include a 2- to 4-fold higher risk of stress-dependent myocardial infarction in women, and up to 10-fold higher risk of Takotsubo syndrome-a stress-dependent coronary-myocardial disorder most prevalent in post-menopausal women. Sex differences arise at all levels of the stress response: from initial perception of stress to behavioural, cognitive, and affective responses and longer-term disease outcomes. These fundamental differences involve interactions between chromosomal and gonadal determinants, (mal)adaptive epigenetic modulation across the lifespan (particularly in early life), and the extrinsic influences of socio-cultural, economic, and environmental factors. Pre-clinical investigations of biological mechanisms support distinct early life programming and a heightened corticolimbic-noradrenaline-neuroinflammatory reactivity in females vs. males, among implicated determinants of the chronic stress response. Unravelling the intrinsic molecular, cellular and systems biological basis of these differences, and their interactions with external lifestyle/socio-cultural determinants, can guide preventative and therapeutic strategies to better target coronary heart disease in a tailored sex-specific manner.

Mitochondrial Quality Control Mechanisms during Diabetic Cardiomyopathy

One of the major complications of diabetes mellitus is diabetic cardiomyopathy. One of the mechanisms that initiates the irreversible deterioration of cardiac function in diabetic cardiomyopathy is mitochondrial dysfunction. Functionally impaired mitochondria result in greater levels of oxidative stress and lipotoxicity, both of which exacerbate mitochondrial damage. Mitochondrial health is constantly monitored by mitochondrial quality control mechanisms. Mitophagy selectively degrades damaged mitochondria, thereby maintaining the healthy pool of mitochondria and preserving myocardial function. Mitophagy in diabetic cardiomyopathy is mediated by multiple mechanisms in a time-dependent manner. Potential targets for the treatment of diabetic cardiomyopathy include increased oxidative stress, mitochondrial dynamics, and mitochondrial clearance. Thus, stimulation of mitophagy represents a promising strategy for the alleviation of diabetic cardiomyopathy.

Recent Experimental Studies of Maternal Obesity, Diabetes during Pregnancy and the Developmental Origins of Cardiovascular Disease

Globally, cardiovascular disease remains the leading cause of death. Most concerning is the rise in cardiovascular risk factors including obesity, diabetes and hypertension among youth, which increases the likelihood of the development of earlier and more severe cardiovascular disease. While lifestyle factors are involved in these trends, an increasing body of evidence implicates environmental exposures in early life on health outcomes in adulthood. Maternal obesity and diabetes during pregnancy, which have increased dramatically in recent years, also have profound effects on fetal growth and development. Mounting evidence is emerging that maternal obesity and diabetes during pregnancy have lifelong effects on cardiovascular risk factors and heart disease development. However, the mechanisms responsible for these observations are unknown. In this review, we summarize the findings of recent experimental studies, showing that maternal obesity and diabetes during pregnancy affect energy metabolism and heart disease development in the offspring, with a focus on the mechanisms involved. We also evaluate early proof-of-concept studies for interventions that could mitigate maternal obesity and gestational diabetes-induced cardiovascular disease risk in the offspring.

The birth of cardiac disease: Mechanisms linking gestational diabetes mellitus and early onset of cardiovascular disease in offspring

Cardiovascular disease (CVD) is the biggest killer worldwide, composing a major economic burden for health care systems. Obesity and diabetes are dual epidemics on the rise and major risk factors predisposing for CVD. Increased obesity- and diabetes-related incidence is now observed among children, adolescents, and young adults. Gestational diabetes mellitus (GDM) is the most common metabolic pregnancy disorder, and its prevalence is rapidly increasing. During pregnancies complicated by GDM, the offspring are exposed to a compromised intrauterine environment characterized by hyperglycemic periods. Unfavorable in utero conditions at critical periods of fetal cardiac development can produce developmental adaptations that remodel the cardiovascular system in a way that can contribute to adult-onset of heart disease due to the programming during fetal life. Epidemiological studies have reported increased cardiovascular complications among GDM-descendants, highlighting the urgent need to investigate and understand the mechanisms modulated during fetal development of in utero GDM-exposed offspring that predispose an individual to increased CVD during life. In this manuscript, we overview previous studies in this area and gather evidence linking GDM and CVD development in the offspring, providing new insights on novel mechanisms contributing to offspring CVD programming by GDM, from the role of maternal-fetal interactions to their impact on fetal cardiovascular development, how the perpetuation of cardiac programming is maintained in postnatal life, and advance the intergenerational implications contributing to increased CVD premature origin. Understanding the perpetuation of CVD can be the first step to manage and reverse this leading cause of morbidity and mortality. This article is categorized under: Reproductive System Diseases > Molecular and Cellular Physiology Cardiovascular Diseases > Molecular and Cellular Physiology Metabolic Diseases > Genetics/Genomics/Epigenetics.

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.

Environmental Fe, Ti, Al, Cu, Hg, Bi, and Si Nanoparticles in the Atrioventricular Conduction Axis and the Associated Ultrastructural Damage in Young Urbanites: Cardiac Arrhythmias Caused by Anthropogenic, Industrial, E-Waste, and Indoor Nanoparticles

Air pollution exposure is a risk factor for arrhythmia. The atrioventricular (AV) conduction axis is key for the passage of electrical signals to ventricles. We investigated whether environmental nanoparticles (NPs) reach the AV axis and whether they are associated with ultrastructural cell damage. Here, we demonstrate the detection of the shape, size, and composition of NPs by transmission electron microscopy (TEM) and energy-dispersive X-ray spectrometry (EDX) in 10 subjects from Metropolitan Mexico City (MMC) with a mean age of 25.3 ± 5.9 and a 71-year-old subject without cardiac pathology. We found that in every case, Fe, Ti, Al, Hg, Cu, Bi, and/or Si spherical or acicular NPs with a mean size of 36 ± 17 nm were present in the AV axis in situ, freely and as conglomerates, within the mitochondria, sarcomeres, lysosomes, lipofuscin, and/or intercalated disks and gap junctions of Purkinje and transitional cells, telocytes, macrophages, endothelium, and adjacent atrial and ventricular fibers. Erythrocytes were found to transfer NPs to the endothelium. Purkinje fibers with increased lysosomal activity and totally disordered myofilaments and fragmented Z-disks exhibited NP conglomerates in association with gap junctions and intercalated disks. AV conduction axis pathology caused by environmental NPs is a plausible and modifiable risk factor for understanding common arrhythmias and reentrant tachycardia. Anthropogenic, industrial, e-waste, and indoor NPs reach pacemaker regions, thereby increasing potential mechanisms that disrupt the electrical impulse pathways of the heart. The cardiotoxic, oxidative, and abnormal electric performance effects of NPs in pacemaker locations warrant extensive research. Cardiac arrhythmias associated with nanoparticle effects could be preventable.

Mitochondrial Transfer Improves Cardiomyocyte Bioenergetics and Viability in Male Rats Exposed to Pregestational Diabetes

Offspring born to diabetic or obese mothers have a higher lifetime risk of heart disease. Previously, we found that rat offspring exposed to late-gestational diabetes mellitus (LGDM) and maternal high-fat (HF) diet develop mitochondrial dysfunction, impaired cardiomyocyte bioenergetics, and cardiac dysfunction at birth and again during aging. Here, we compared echocardiography, cardiomyocyte bioenergetics, oxidative damage, and mitochondria-mediated cell death among control, pregestational diabetes mellitus (PGDM)-exposed, HF-diet-exposed, and combination-exposed newborn offspring. We hypothesized that PGDM exposure, similar to LGDM, causes mitochondrial dysfunction to play a central, pathogenic role in neonatal cardiomyopathy. We found that PGDM-exposed offspring, similar to LGDM-exposed offspring, have cardiac dysfunction at birth, but their isolated cardiomyocytes have seemingly less bioenergetics impairment. This finding was due to confounding by impaired viability related to poorer ATP generation, more lipid peroxidation, and faster apoptosis under metabolic stress. To mechanistically isolate and test the role of mitochondria, we transferred mitochondria from normal rat myocardium to control and exposed neonatal rat cardiomyocytes. As expected, transfer provides a respiratory boost to cardiomyocytes from all groups. They also reduce apoptosis in PGDM-exposed males, but not in females. Findings highlight sex-specific differences in mitochondria-mediated mechanisms of developmentally programmed heart disease and underscore potential caveats of therapeutic mitochondrial transfer.