Maternal Separation Induces Long-Term Alterations in the Cardiac Oxytocin Receptor and Cystathionine γ-Lyase Expression in Mice

Transcriptome Analysis Reveals Enhancement of Cardiogenesis-Related Signaling Pathways by S-Nitroso- N -Pivaloyl- d -Penicillamine: Implications for Improved Diastolic Function and Cardiac Performance

ABSTRACT

We previously reported a novel compound called S-nitroso- N -pivaloyl- d -penicillamine (SNPiP), which was screened from a group of nitric oxide donor compounds with a basic chemical structure of S-nitroso- N -acetylpenicillamine, to activate the nonneuronal acetylcholine system. SNPiP-treated mice exhibited improved cardiac output and enhanced diastolic function, without an increase in heart rate. The nonneuronal acetylcholine-activating effects included increased resilience to ischemia, modulation of energy metabolism preference, and activation of angiogenesis. Here, we performed transcriptome analysis of SNPiP-treated mice ventricles to elucidate how SNPiP exerts beneficial effects on cardiac function. A time-course study (24 and 48 hours after SNPiP administration) revealed that SNPiP initially induced Wnt and cyclic guanosine monophosphate-protein kinase G signaling pathways, along with upregulation of genes involved in cardiac muscle tissue development and oxytocin signaling pathway. We also observed enrichment of glycolysis-related genes in response to SNPiP treatment, resulting in a metabolic shift from oxidative phosphorylation to glycolysis, which was suggested by reduced cardiac glucose contents while maintaining adenosine tri-phosphate levels. In addition, SNPiP significantly upregulated atrial natriuretic peptide and sarcolipin, which play crucial roles in calcium handling and cardiac performance. These findings suggest that SNPiP may have therapeutic potential based on the pleiotropic mechanisms elucidated in this study.

Association of early life adversity with cardiovascular disease and its potential mechanisms: a narrative review

Strong epidemiological evidence has shown that early life adversity (ELA) has a profound negative impact on health in adulthood, including an increased risk of cardiovascular disease, the leading cause of death worldwide. Here, we review cohort studies on the effects of ELA on cardiovascular outcomes and the possible underlying mechanisms. In addition, we summarize relevant studies in rodent models of ELA. This review reveals that the prevalence of ELA varies between regions, time periods, and sexes. ELA increases cardiovascular health risk behaviors, susceptibility to mental illnesses, and neuroendocrine and immune system dysfunction in humans. Rodent models of ELA have been developed and show similar cardiovascular outcomes to those in humans but cannot fully replicate all ELA subtypes. Therefore, combining cohort and rodent studies to further investigate the mechanisms underlying the association between ELA and cardiovascular diseases may be a feasible future research strategy.

Relationship between oxytocin receptor gene polymorphism and hypertension in Turkish population

INTRODUCTION AND OBJECTIVES

Known to play a key role in uterine contraction and milk ejection, the neuropeptide, oxytocin, has cardiovascular effects. To date, the known cardiovascular effects of oxytocin are blood pressure lowering (caused by natriuresis and atrial natriuretic peptide release), negative inotropic and chronotropic effect caused by parasympathetic neuromodulation, anti-stress effect and vasodilation mediated by activation of the nitric oxide pathway. The clinical significance of the rs2268498 polymorphism in oxytocin receptors in these effects is controversial. Based on the known genetic inheritance of hypertension, our research aimed to determine whether the presence of the rs2268498 oxytocin receptor (OXTR) allele C affects hypertension in our region.

METHODS

This article is a case-control study conducted in the Turkish population. About 140 normotensive and 140 isolated hypertensive volunteers included in the research and genotyped with real-time PCR hybridization method via melt curve analysis.

RESULTS

Oxytocin receptor rs2268498 polymorphism was assessed in terms of the risk of hypertension and hypertensive individuals were compared to the control group. OXTR rs2268498 polymorphism was not found to be a significant risk factor for dominant, recessive and additive modeled hypertension (ORdominant: 0.966, 95% CI: 0.57-1.61, p: 0.9; ORrecessive: 1, 95% CI: 0.58-1.71, p: 1.0 and ORoverall: 0.98, chi2=0.01).

CONCLUSION

We concluded that rs2268498 single nucleotide polymorphism is not a risk factor for hypertension in our region.

Evaluation of rosmarinic acid against myocardial infarction in maternally separated rats

Depression and coronary heart diseases are the common comorbid disorder affecting humans globally. The present study evaluated the effectiveness of rosmarinic acid (RA) against myocardial infarction (MI) in comorbid depression induced by maternal separation in rats. Maternal stress is one of the childhood crises that may be a potential risk factor for coronary heart disease in later part of life. As per protocol, 70-80% of pups were separated daily for 3 h between postnatal day 1 (PND1) and postnatal day 21 (PND21). Forced-swim test, sucrose preference test, and electrocardiography were performed during the experiment. Body weight was measured on PND0, PND35, and PND55. Orally rosmarinic acid (25 mg/kg and 50 mg/kg) and fluoxetine (10 mg/kg) was done from PND35 to PND55. On PND53 and PND54, isoproterenol (100 mg/kg, subcutaneously) was administered to induce myocardial infarction. On PND55, blood was collected and animals sacrificed, and plasma corticosterone, brain-derived neurotrophic factor, cardiac biomarkers, interleukine-10, and anti-oxidant parameters were measured. Rosmarinic acid and fluoxetine ameliorated the maternal separation-induced increase in immobility period, anhedonia, body weight, ST elevation, corticosterone, creatine kinase-MB (CK-MB), and lactate dehydrogenase (LDH). At the same time, both drugs elevated the tissue levels of BDNF, IL-10, glutathione, and superoxide dismutase activity. This study provides the first experimental evidence that maternal stress is an independent risk factor of cardiac abnormalities in rats. Moreover, maternal stress synergistically increases the severity of cardiac abnormalities induced by isoproterenol. Interestingly, fluoxetine and rosmarinic acid effectively ameliorated behavioral anomalies and myocardial infarction in maternally separated rats. Schematic representation of possible molecular mechanism of action of rosmarinic acid against MS-induced myocardial infarction. RA, rosmarinic acid; MS, maternal separation; PND, postnatal days; ISO, isoproterenol; BDNF, brain-derived neurotrophic factor; GSH, glutathione; SOD, superoxide dismutase; IL-10, interleukin-10; MI, myocardial infarction.

Childhood Separation from Parents with Cognitive and Psychopathological Outcomes in Adolescence

To examine the effects of childhood parent-child separation with varying duration and form on later cognitive performance and psychopathological problems over a 6-year period, we use data from the China Family Panel Study, which is an ongoing, prospective nationally representative study across 25 provinces in China. Of the 4033 children aged 4-10 years followed in 2012, 3522 children with complete data on separation from fathers and mothers were included. In 2018, 2560 participants were followed and interviewed to assess cognitive performance, behavioral problems as well as depressive symptoms at age 10-16 years. A total of 3522 children (mean [SD] age at baseline, 6.9 [2.0] years) were included. About 17.9% and 13.3% had separated from father and mother over 11 months or more in the year prior to the survey. Prolonged separation from parents was associated with lower scores in vocabulary (maternal: adjusted β = -1.64, P = 0.002; paternal: adjusted β = -1.58, P<0.001) and mathematics performance (maternal: adjusted β = -1.10, P = 0.009; paternal: adjusted β = -0.94, P = 0.004) over a 6-year period. Prolonged maternal separation was associated with 0.34-point higher internalizing behaviors (P<0.001) and 0.21-point higher externalizing behaviors (P = 0.009), as well as 0.89-point higher depressive symptoms (P = 0.018), while prolonged paternal separation was associated with 0.23-point higher internalizing behaviors (P = 0.005) and 0.76-point higher depressive symptoms (P = 0.011). The finding demonstrates substantial negative impacts of childhood paternal and maternal separations on cognitive and mental well-being during adolescence, which might be dependent on the "stress-dose" (duration of separation) and urban-rural residence. This article is protected by copyright. All rights reserved.

Early life adversity drives sex-specific anhedonia and meningeal immune gene expression through mast cell activation

Exposure to early life adversity (ELA) in the form of physical and/or psychological abuse or neglect increases the risk of developing psychiatric and inflammatory disorders later in life. It has been hypothesized that exposure to ELA results in persistent, low grade inflammation that leads to increased disease susceptibility by amplifying the crosstalk between stress-processing brain networks and the immune system, but the mechanisms remain largely unexplored. The meninges, a layer of three overlapping membranes that surround the central nervous system (CNS)- dura mater, arachnoid, and piamater - possess unique features that allow them to play a key role in coordinating immune trafficking between the brain and the peripheral immune system. These include a network of lymphatic vessels that carry cerebrospinal fluid from the brain to the deep cervical lymph nodes, fenestrated blood vessels that allow the passage of molecules from blood to the CNS, and a rich population of resident mast cells, master regulators of the immune system. Using a mouse model of ELA consisting of neonatal maternal separation plus early weaning (NMSEW), we sought to explore the effects of ELA on sucrose preference behavior, dura mater expression of inflammatory markers and mast cell histology in adult male and female C57Bl/6 mice. We found that NMSEW alone does not affect sucrose preference behavior in males or females, but it increases the dura mater expression of the genes coding for mast cell protease CMA1 (cma1) and the inflammatory cytokine TNF alpha (tnf alpha) in females. When NMSEW is combined with an adult mild stress (that does not affect behavior or gene expression in NH animals) females show reduced sucrose preference and even greater increases in meningeal cma1 levels. Interestingly, systemic administration of the mast cell stabilizer Ketotifen before exposure to adult stress prevents both, reduction in sucrose preference an increases in cma1 expression in NMSEW females, but facilitates stress-induced sucrose anhedonia in NMSEW males and NH females. Finally, histological analyses showed that, compared to males, females have increased baseline activation levels of mast cells located in the transverse sinus of the dura mater, where the meningeal lymphatics run along, and that, in males and females exposed to adult stress, NMSEW increases the number of mast cells in the interparietal region of the dura mater and the levels of mast cell activation in the sagittal sinus regions of the dura mater. Together, our results indicate that ELA induces long-term meningeal immune gene changes and heightened sensitivity to adult stress-induced behavioral and meningeal immune responses and that these effects could mediated via mast cells.

Brain Histology and Immunohistochemistry After Resuscitation From Hemorrhagic Shock in Swine With Pre-Existing Atherosclerosis and Sodium Thiosulfate (Na2S2O3) Treatment

Background

The hydrogen sulfide (H₂S) and the oxytocin/oxytocin receptor (OT/OTR) systems interact in the central nervous and cardiovascular system. As a consequence of osmotic balance stress, H₂S stimulates OT release from the paraventricular nuclei (PVN) in the hypothalamic regulation of blood volume and pressure. Hemorrhagic shock (HS) represents one of the most pronounced acute changes in blood volume, which, moreover, may cause at least transient brain tissue hypoxia. Atherosclerosis is associated with reduced vascular expression of the main endogenous H₂S producing enzyme cystathionine-γ-lyase (CSE), and, hence, exogenous H₂S administration could be beneficial in these patients, in particular after HS. However, so far cerebral effects of systemic H₂S administration are poorly understood. Having previously shown lung-protective effects of therapeutic Na₂S₂O₃ administration in a clinically relevant, long-term, porcine model of HS and resuscitation we evaluated if these protective effects were extended to the brain.

Methods

In this study, available unanalyzed paraffin embedded brain sections (Na₂S₂O₃N = 8 or vehicle N = 5) of our recently published HS study were analyzed via neuro-histopathology and immunohistochemistry for the endogenous H₂S producing enzymes, OT, OTR, and markers for brain injury and oxidative stress (glial fibrillary acidic protein (GFAP) and nitrotyrosine).

Results

Neuro-histopathological analysis revealed uninjured brain tissue with minor white matter edema. Protein quantification in the hypothalamic PVN showed no significant inter-group differences between vehicle or Na₂S₂O₃ treatment.

Conclusions

The endogenous H₂S enzymes, OT/OTR co-localized in magnocellular neurons in the hypothalamus, which may reflect their interaction in response to HS-induced hypovolemia. The preserved blood brain barrier (BBB) may have resulted in impermeability for Na₂S₂O₃ and no inter-group differences in the PVN. Nonetheless, our results do not preclude that Na₂S₂O₃ could have a therapeutic benefit in the brain in an injury that disrupts the BBB, e.g., traumatic brain injury (TBI) or acute subdural hematoma (ASDH).

H2S in Critical Illness—A New Horizon for Sodium Thiosulfate?

Ever since the discovery of endogenous H₂S and the identification of its cytoprotective properties, efforts have been made to develop strategies to use H₂S as a therapeutic agent. The ability of H₂S to regulate vascular tone, inflammation, oxidative stress, and apoptosis might be particularly useful in the therapeutic management of critical illness. However, neither the inhalation of gaseous H₂S, nor the administration of inorganic H₂S-releasing salts or slow-releasing H₂S-donors are feasible for clinical use. Na₂S₂O₃ is a clinically approved compound with a good safety profile and is able to release H₂S, in particular under hypoxic conditions. Pre-clinical studies show promise for Na₂S₂O₃ in the acute management of critical illness. A current clinical trial is investigating the therapeutic potential for Na₂S₂O₃ in myocardial infarct. Pre-eclampsia and COVID-19 pneumonia might be relevant targets for future clinical trials.

Early Life Stress, Brain Development, and Obesity Risk: Is Oxytocin the Missing Link?

Obesity disease results from a dysfunctional modulation of the energy balance whose master regulator is the central nervous system. The neural circuitries involved in such function complete their maturation during early postnatal periods, when the brain is highly plastic and profoundly influenced by the environment. This phenomenon is considered as an evolutionary strategy, whereby metabolic functions are adjusted to environmental cues, such as food availability and maternal care. In this timeframe, adverse stimuli may program the body metabolism to maximize energy storage abilities to cope with hostile conditions. Consistently, the prevalence of obesity is higher among individuals who experienced early life stress (ELS). Oxytocin, a hypothalamic neurohormone, regulates the energy balance and modulates social, emotional, and eating behaviors, exerting both central and peripheral actions. Oxytocin closely cooperates with leptin in regulating energy homeostasis. Both oxytocin and leptin impact the neurodevelopment during critical periods and are affected by ELS and obesity. In this review article, we report evidence from the literature describing the effect of postnatal ELS (specifically, disorganized/inconstant maternal care) on the vulnerability to obesity with a focus on the role of oxytocin. We emphasize the existing research gaps and highlight promising directions worthy of exploration. Based on the available data, alterations in the oxytocin system may in part mediate the ELS-induced susceptibility to obesity.

The Gasotransmitter Hydrogen Sulfide and the Neuropeptide Oxytocin as Potential Mediators of Beneficial Cardiovascular Effects through Meditation after Traumatic Events

Trauma and its related psychological and somatic consequences are associated with higher cardiovascular morbidity. The regulation of both the gasotransmitter hydrogen sulfide (H2S) and the neuropeptide oxytocin (OT) have been reported to be affected during physical and psychological trauma. Both mediators are likely molecular correlates of trauma-induced cardiovascular complications, because they share parallel roles and signaling pathways in the cardiovascular system, both locally as well as on the level of central regulation and the vagus nerve. Meditation can alter the structure of specific brain regions and can have beneficial effects on cardiovascular health. This perspective article summarizes the evidence pointing toward the significance of H2S and OT signaling in meditation-mediated cardio-protection.

Biological Connection of Psychological Stress and Polytrauma under Intensive Care: The Role of Oxytocin and Hydrogen Sulfide

This paper explored the potential mediating role of hydrogen sulfide (H2S) and the oxytocin (OT) systems in hemorrhagic shock (HS) and/or traumatic brain injury (TBI). Morbidity and mortality after trauma mainly depend on the presence of HS and/or TBI. Rapid "repayment of the O2 debt" and prevention of brain tissue hypoxia are cornerstones of the management of both HS and TBI. Restoring tissue perfusion, however, generates an ischemia/reperfusion (I/R) injury due to the formation of reactive oxygen (ROS) and nitrogen (RNS) species. Moreover, pre-existing-medical-conditions (PEMC's) can aggravate the occurrence and severity of complications after trauma. In addition to the "classic" chronic diseases (of cardiovascular or metabolic origin), there is growing awareness of psychological PEMC's, e.g., early life stress (ELS) increases the predisposition to develop post-traumatic-stress-disorder (PTSD) and trauma patients with TBI show a significantly higher incidence of PTSD than patients without TBI. In fact, ELS is known to contribute to the developmental origins of cardiovascular disease. The neurotransmitter H2S is not only essential for the neuroendocrine stress response, but is also a promising therapeutic target in the prevention of chronic diseases induced by ELS. The neuroendocrine hormone OT has fundamental importance for brain development and social behavior, and, thus, is implicated in resilience or vulnerability to traumatic events. OT and H2S have been shown to interact in physical and psychological trauma and could, thus, be therapeutic targets to mitigate the acute post-traumatic effects of chronic PEMC's. OT and H2S both share anti-inflammatory, anti-oxidant, and vasoactive properties; through the reperfusion injury salvage kinase (RISK) pathway, where their signaling mechanisms converge, they act via the regulation of nitric oxide (NO).

H2S and Oxytocin Systems in Early Life Stress and Cardiovascular Disease

Today it is well established that early life stress leads to cardiovascular programming that manifests in cardiovascular disease, but the mechanisms by which this occurs, are not fully understood. This perspective review examines the relevant literature that implicates the dysregulation of the gasomediator hydrogen sulfide and the neuroendocrine oxytocin systems in heart disease and their putative mechanistic role in the early life stress developmental origins of cardiovascular disease. Furthermore, interesting hints towards the mutual interaction of the hydrogen sulfide and OT systems are identified, especially with regards to the connection between the central nervous and the cardiovascular system, which support the role of the vagus nerve as a communication link between the brain and the heart in stress-mediated cardiovascular disease.

Aberrant Early in Life Stimulation of the Stress-Response System Affects Emotional Contagion and Oxytocin Regulation in Adult Male Mice

Results over the last decades have provided evidence suggesting that HPA axis dysfunction is a major risk factor predisposing to the development of psychopathological behaviour. This susceptibility can be programmed during developmental windows of marked neuroplasticity, allowing early-life adversity to convey vulnerability to mental illness later in life. Besides genetic predisposition, also environmental factors play a pivotal role in this process, through embodiment of the mother's emotions, or via nutrients and hormones transferred through the placenta and the maternal milk. The aim of the current translational study was to mimic a severe stress condition by exposing female CD-1 mouse dams to abnormal levels of corticosterone (80 µg/mL) in the drinking water either during the last week of pregnancy (PreCORT) or the first one of lactation (PostCORT), compared to an Animal Facility Rearing (AFR) control group. When tested as adults, male mice from PostCORT offspring and somewhat less the PreCORT mice exhibited a markedly increased corticosterone response to acute restraint stress, compared to perinatal AFR controls. Aberrant persistence of adolescence-typical increased interest towards novel social stimuli and somewhat deficient emotional contagion also characterised profiles in both perinatal-CORT groups. Intranasal oxytocin (0 or 20.0 µg/kg) generally managed to reduce the stress response and restore a regular behavioural phenotype. Alterations in density of glucocorticoid and mineralocorticoid receptors, oxytocin and µ- and κ-opioid receptors were found. Changes differed as a function of brain areas and the specific age window of perinatal aberrant stimulation of the HPA axis. Present results provided experimental evidence in a translational mouse model that precocious adversity represents a risk factor predisposing to the development of psychopathological behaviour.

ΔMST and the Regulation of Cardiac CSE and OTR Expression in Trauma and Hemorrhage

Genetic deletion of 3-mercaptopyruvate sulfurtransferase (MST) is known to result in hypertension and cardiac hypertrophy in older mice, and is associated with increased anxiety-like behaviors. Endogenous hydrogen sulfide (H2S) produced by MST in the mitochondria is also known to be involved in physiological and cellular bioenergetics, and its dysfunction associated with depressive behavior and increased cardiovascular morbidity. Interestingly, early life stress has been shown to lead to a significant loss of cystathionine-γ-lyase (CSE) and oxytocin receptor (OTR) expression in the heart. Thus, we were interested in testing the hypothesis of whether genetic MST mutation (ΔMST) would affect cardiac CSE and OTR expression and affect the mitochondrial respiration in a clinically relevant, resuscitated, mouse model of trauma and hemorrhagic shock. In ΔMST mice, we found a reduction of CSE and OTR in both the naive as well as injured state, in contrast to the wild type (wt) controls. Interestingly, the ΔMST showed a different complex IV response to injury than the wt controls, although our claims are based on the non-demonstrated assumption that naive wt and naive ΔMST mice have comparable complex IV activity. Finally, hemorrhagic shock led to a reduction of CSE and OTR, confirming previous results in the injured mouse heart. To date, the exact mechanisms of the cardiac interaction between H2S and OT are not clear, but they point the way to potential cardioprotective therapies.

The Interaction of the Endogenous Hydrogen Sulfide and Oxytocin Systems in Fluid Regulation and the Cardiovascular System

The purpose of this review is to explore the parallel roles and interaction of hydrogen sulfide (H2S) and oxytocin (OT) in cardiovascular regulation and fluid homeostasis. Their interaction has been recently reported to be relevant during physical and psychological trauma. However, literature reports on H2S in physical trauma and OT in psychological trauma are abundant, whereas available information regarding H2S in psychological trauma and OT in physical trauma is much more limited. This review summarizes recent direct and indirect evidence of the interaction of the two systems and their convergence in downstream nitric oxide-dependent signaling pathways during various types of trauma, in an effort to better understand biological correlates of psychosomatic interdependencies.

Cerebral Immunohistochemical Characterization of the H2S and the Oxytocin Systems in a Porcine Model of Acute Subdural Hematoma

The hydrogen sulfide (H₂S) and the oxytocin/oxytocin receptor (OT/OTR) systems interact in trauma and are implicated in vascular protection and regulation of fluid homeostasis. Acute brain injury is associated with pressure-induced edema formation, blood brain barrier disruption, and neuro-inflammation. The similarities in brain anatomy: size, gyrencephalic organization, skull structure, may render the pig a highly relevant model for translational medicine. Cerebral biomarkers for pigs for pathophysiological changes and neuro-inflammation are limited. The current study aims to characterize the localization of OT/OTR and the endogenous H₂S producing enzymes together with relevant neuro-inflammatory markers on available porcine brain tissue from an acute subdural hematoma (ASDH) model. In a recent pilot study, anesthetized pigs underwent ASDH by injection of 20 mL of autologous blood above the left parietal cortex and were resuscitated with neuro-intensive care measures. After 54 h of intensive care, the animals were sacrificed, the brain was removed and analyzed via immunohistochemistry. The endogenous H₂S producing enzymes cystathionine-ɤ-lyase (CSE) and cystathionine-β-synthase (CBS), the OTR, and OT were localized in neurons, vasculature and parenchyma at the base of sulci, where pressure-induced injury leads to maximal stress in the gyrencephalic brain. The pathophysiological changes in response to brain injury in humans and pigs, we show here, are comparable. We additionally identified modulators of brain injury to further characterize the pathophysiology of ASDH and which may indicate future therapeutic approaches.

The Role of Glucocorticoid Receptor and Oxytocin Receptor in the Septic Heart in a Clinically Relevant, Resuscitated Porcine Model With Underlying Atherosclerosis

The pathophysiology of sepsis-induced myocardial dysfunction is not resolved to date and comprises inflammation, barrier dysfunction and oxidative stress. Disease-associated reduction of tissue cystathionine-γ-lyase (CSE) expression, an endogenous H₂S-producing enzyme, is associated with oxidative stress, barrier dysfunction and organ injury. CSE-mediated cardio-protection has been suggested to be related the upregulation of oxytocin receptor (OTR). CSE can also mediate glucocorticoid receptor (GR) signaling, which is important for normal heart function. A sepsis-related loss of cardiac CSE expression associated with impaired organ function has been reported previously. The aim of this current post hoc study was to investigate the role of cardiac GR and OTR after polymicrobial sepsis in a clinically relevant, resuscitated, atherosclerotic porcine model. Anesthetized and instrumented FBM (Familial Hypercholesterolemia Bretoncelles Meishan) pigs with high fat diet-induced atherosclerosis underwent poly-microbial septic shock (n = 8) or sham procedure (n = 5), and subsequently received intensive care therapy with fluid and noradrenaline administration for 24 h. Cardiac protein expression and mRNA levels were analyzed. Systemic troponin, a marker of cardiac injury, was significantly increased in septic animals in contrast to sham, whereas OTR and GR expression in septic hearts were reduced, along with a down-regulation of anti-inflammatory GR target genes and the antioxidant transcription factor NRF2. These results suggest a potential interplay between GR, CSE, and OTR in sepsis-mediated oxidative stress, inflammation and cardiac dysfunction.