Prenatal methamphetamine differentially alters myocardial sensitivity to ischemic injury in male and female adult hearts

Maternal use of methamphetamine induces sex-dependent changes in myocardial gene expression in adult offspring

Methamphetamine is a commonly abused illicit stimulant that has prevalent use among women of child-bearing age. While there are extensive studies on the neurological effects of prenatal methamphetamine exposure, relatively little is known about the effect of prenatal methamphetamine on the adult cardiovascular system. Earlier work demonstrated that prenatal methamphetamine exposure sex dependently (females only) sensitizes the adult heart to ischemic injury. These data suggest that prenatal exposure to methamphetamine may induce sex-dependent changes in cardiac gene expression that persist in adult offspring. The goal of this study was to test the hypothesis that prenatal methamphetamine exposure induces changes in cardiac gene expression that persist in the adult heart. Hearts of prenatally exposed female offspring exhibited a greater number of changes in gene expression compared to male offspring (184 changes compared with 74 in male offspring and 89 changes common between both sexes). Dimethylarginine dimethylaminohydrolase 2 and 3-hydroxybutyrate dehydrogenase 1 (genes implicated in heart failure) were shown by Western Blot to be under expressed in adult females that were prenatally exposed to methamphetamine, while males were deficient in 3-Hydroxybutyrate Dehydrogenase 1 only. These data indicate that prenatal methamphetamine exposure induces changes in gene expression that persist into adulthood. This is consistent with previous findings that prenatal methamphetamine sex dependently sensitizes the adult heart to ischemic injury and may increase the risk of developing cardiac disorders during adulthood.

Prenatal Methamphetamine Hydrochloride Exposure Leads to Signal Transduction Alteration and Cell Death in the Prefrontal Cortex and Amygdala of Male and Female Rats' Offspring

In the last decade, there has been a great increase in methamphetamine hydrochloride (METH) abuse by pregnant women that exposes fetus and human offspring to a wide variety of developmental impairments that may be the underlying causes of future psychosocial issues. Herein, we investigated whether prenatal METH exposure with different doses (2 and 5 mg/kg) could influence neuronal cell death and antioxidant level in the different brain regions of adult male and female offspring. Adult male and female Wistar rats prenatally exposed to METH (2 or 5 mg/kg) and/or saline was used in this study. At week 12, adult rats' offspring were decapitated to collect different brain region tissues including amygdala (AMY) and prefrontal cortices (PFC). Western blot analysis was performed to evaluate the apoptosis- and autophagy-related markers, and enzymatic assay was used to measure the level of catalase and also reduced glutathione (GSH). Our results showed that METH exposure during pregnancy increased the level of apoptosis (BAX/Bcl-2 and Caspase-3) and autophagy (Beclin-1 and LC3II/LC3I) in the PFC and AMY areas of both male and female offspring's brain. Also, we found an elevation in the GSH content of all both mentioned brain areas and catalase activity of PFC in the offspring's brain. These changes were more significant in female offspring. Being prenatally exposed to METH increased cell death at least partly via apoptosis and autophagy in AMY and PFC of male and female offspring's brain, while the antioxidant system tried to protect cells in these regions.

Methamphetamine use during the first or second half of pregnancy worsens cardiac ischemic injury in adult female offspring

There is growing evidence that methamphetamine use during pregnancy may produce detrimental cardiovascular effects in the adult offspring. Prior work demonstrated that chronic methamphetamine exposure throughout the gestational period causes adult female offspring to become hypersensitive to myocardial ischemic injury. The goal of the present study was to determine whether this methamphetamine-induced effect occurs early or late in the gestational period. Pregnant female rats were divided into 4 experimental groups. Groups 1 and 2 received subcutaneous injections of saline (group 1) or methamphetamine (5 mg/kg) (group 2) throughout the gestational period. Group 3 received methamphetamine injections on days 1-11 and saline on days 12-22, and group 4 received saline on days 1-11 and methamphetamine on days 12-22. Hearts were isolated from adult (8 weeks) female offspring and subjected to 30 min ischemia and 2 hours reperfusion on a Langendorff isolated heart apparatus. Contractile function was measured via an intraventricular balloon, and infarct size was measured by triphenyltetrazolium chloride staining. Infarcts were significantly larger in methamphetamine exposed offspring regardless of whether they had been exposed to methamphetamine during the first half or the second half of the gestational period. Prenatal exposure to methamphetamine had no effect on preischemic contractile function or postischemic recovery of contractile function. These data indicate that methamphetamine use during either the first half or second half of pregnancy increases susceptibility to myocardial infarction in adult female offspring. These data provide further evidence that prenatal exposure to methamphetamine may increase the risk of developing cardiovascular diseases during adulthood.

Prenatal Exposure to Methamphetamine Causes Vascular Dysfunction in Adult Male Rat Offspring

Methamphetamine use during pregnancy can have negative consequences on the offspring. However, most studies investigating the impact of prenatal exposure to methamphetamine have focused on behavioral and neurological outcomes. Relatively little is known regarding the impact of prenatal methamphetamine on the adult cardiovascular system. This study investigated the impact of chronic fetal exposure to methamphetamine on vascular function in adult offspring. Pregnant female rats received daily saline or methamphetamine (5 mg/kg) injections starting on gestational day 1 and continuing until the pups were born. Vascular function was assessed in 5 month old offspring. Prenatal methamphetamine significantly decreased both the efficacy and potency of acetylcholine-induced relaxation in isolated male (but not female) aortas when perivascular adipose tissue (PVAT) remained intact. However, prenatal methamphetamine had no impact on acetylcholine-induced relaxation when PVAT was removed. Nitroprusside-induced relaxation of the aorta was unaffected by prenatal methamphetamine. Angiotensin II-induced contractile responses were significantly potentiated in male (but not female) aortas regardless of the presence of PVAT. This effect was reversed by L-nitro arginine methyl ester (L-NAME). Serotonin- and phenylephrine-induced contraction were unaffected by prenatal methamphetamine. Prenatal methamphetamine had no impact on acetylcholine-induced relaxation of third order mesenteric arteries and no effect on basal blood pressure. These data provide evidence that prenatal exposure to methamphetamine sex-dependently alters vasomotor function in the vasculature and may increase the risk of developing vascular disorders later in adult life.

The Adverse Effects of Prenatal METH Exposure on the Offspring: A Review

Abuse of methamphetamine (METH), an illicit psychostimulant, is a growing public health issue. METH abuse during pregnancy is on the rise due to its stimulant, anorectic, and hallucinogenic properties. METH can lead to multiple organ toxicity in adults, including neurotoxicity, cardiovascular toxicity, and hepatotoxicity. It can also cross the placental barrier and have long-lasting effects on the fetus. This review summarizes neurotoxicity, cardiovascular toxicity, hepatotoxicity, toxicity in other organs, and biomonitoring of prenatal METH exposure, as well as the possible emergence of sensitization associated with METH. We proposed the importance of gut microbiota in studying prenatal METH exposure. There is rising evidence of the adverse effects of METH exposure during pregnancy, which are of significant concern.

Sex-dependent right ventricular hypertrophic gene changes after methamphetamine treatment in mice

Methamphetamine (MA) abuse is associated with the development of pulmonary arterial hypertension (PAH) and subsequent right ventricular failure. A recent clinical study demonstrated that female sex is a major risk factor for MA-induced PAH. The mechanisms associated with increased prevalence and severity of MA-induced PAH in females are still unclear. We hypothesized that MA may promote changes in gene expression in the right ventricle contributing to the development and/or worsening of PAH in females. Male and female C57BL/6 mice were treated with either MA or vehicle. Right and left ventricular systolic pressures (RVSP and LVSP, respectively) were assessed and tissue samples were collected for gene expression and histology. LVSP and RVSP were not affected by MA in either males or females. Right ventricular hypertrophy was significantly increased by MA in females but it was not affected by MA in males. In the female mice, MA-induced right ventricular hypertrophy was associated with increased expression of brain natriuretic peptide gene and members of the TGF-β receptor signaling pathway such as TGF-β receptor-1, smad3 and smad7. In male mice, there were no changes in right ventricular gene expression. Our results suggest that MA caused right ventricular hypertrophy in female mice, but not in males and that this was associated with an increase in hypertrophic genes. The right ventricular hypertrophy was not dependent on increased RVSP suggesting a direct effect of MA on the right ventricle. If this translates to PAH patients, it might explain the poor outcome observed in MA-associated female PAH patients.

Methamphetamine-induced changes in myocardial gene transcription are sex-dependent

BACKGROUND

Prior work demonstrated that female rats (but not their male littermates) exposed to methamphetamine become hypersensitive to myocardial ischemic injury. Importantly, this sex-dependent effect persists following 30 days of subsequent abstinence from the drug, suggesting that it may be mediated by long term changes in gene expression that are not rapidly reversed following discontinuation of methamphetamine use. The goal of the present study was to determine whether methamphetamine induces sex-dependent changes in myocardial gene expression and whether these changes persist following subsequent abstinence from methamphetamine.

RESULTS

Methamphetamine induced changes in the myocardial transcriptome were significantly greater in female hearts than male hearts both in terms of the number of genes affected and the magnitude of the changes. The largest changes in female hearts involved genes that regulate the circadian clock (Dbp, Per3, Per2, BMal1, and Npas2) which are known to impact myocardial ischemic injury. These genes were unaffected by methamphetamine in male hearts. All changes in gene expression identified at day 11 returned to baseline by day 30.

CONCLUSIONS

These data demonstrate that female rats are more sensitive than males to methamphetamine-induced changes in the myocardial transcriptome and that methamphetamine does not induce changes in myocardial transcription that persist long term after exposure to the drug has been discontinued.

Does Prenatal Exposure to CNS Stimulants Increase the Risk of Cardiovascular Disease in Adult Offspring?

Prenatal exposure to an adverse uterine environment can have long lasting effects on adult offspring through DNA methylation, histone acetylation, and other epigenetic effects that alter gene expression and physiology. It is well-known that consumption of CNS stimulants such as caffeine, nicotine, amphetamines, and cocaine during pregnancy can adversely impact the offspring. However, most work in this area has focused on neurological and behavioral outcomes and has been limited to assessments in young offspring. The impact of prenatal exposure to these agents on the adult cardiovascular system has received relatively little attention. Evidence from both animal and human studies indicate that exposure to CNS stimulants during the gestational period can negatively impact the adult heart and vasculature, potentially leading to cardiovascular diseases later in life. This review discusses our current understanding of the impact of prenatal exposure to cocaine, methamphetamine, nicotine, and caffeine on the adult cardiovascular system.

Prenatal exposure to methamphetamine in rats induces endothelial dysfunction in male but not female adult offspring

In utero exposure to methamphetamine results in significant developmental, neurological, and behavioral deficits in offspring. However, very little is known about the cardiovascular effects of prenatal methamphetamine exposure in adult offspring. We hypothesized that prenatal methamphetamine exposure causes adverse cardiovascular effects in adult offspring. The aims of this study were to test the effects of prenatal methamphetamine exposure on blood pressure and endothelial function in male and female adult rat offspring. Pregnant rats were injected with methamphetamine (5 mg kg^-1 day^-1) or saline throughout pregnancy. Conscious blood pressure and vascular function in mesenteric-resistance arteries were measured in male and female adult offspring using tail cuff and myography, respectively (beginning at 8 weeks old). In adult male offspring, but not in adult female offspring, endothelium-dependent relaxation to acetylcholine was impaired in methamphetamine-exposed compared to saline-exposed rats. Vascular relaxation to diethylamine NONOate diethylammonium salt was not impacted by gender or prenatal exposure. Prenatal methamphetamine exposure had no effect on systolic blood pressure in offspring of either gender. These data suggest that prenatal methamphetamine exposure adversely affects endothelial function in a sex-dependent manner. Clinically, these data suggest that adult males with a history of prenatal methamphetamine exposure may be at greater risk of developing cardiovascular disease due to endothelial dysfunction.

Short term methylphenidate treatment does not increase myocardial injury in the ischemic rat heart

Methylphenidate is commonly used for the treatment of attention deficit hyperactivity disorder. The cardiovascular safety of methylphenidate has been a subject of debate with some studies indicating that methylphenidate increases the likelihood of experiencing a myocardial infarction. However, it is unknown whether methylphenidate worsens the extent of injury during an ischemic insult. The purpose of this study was to determine whether short term exposure to methylphenidate increases the extent of myocardial injury during an ischemic insult. Male and female rats received methylphenidate (5 mg/kg/day) or saline for 10 days by oral gavage. Hearts were subjected to 20 min of ischemia and 2 h of reperfusion on a Langendorff isolated heart apparatus on day 11. Cardiac contractile function was monitored via an intraventricular balloon and myocardial injury was assessed by triphenyltetrazolium chloride staining. Methylphenidate significantly increased locomotor activity in male and female rats, confirming absorption of this psychostimulant into the central nervous system. Male hearts had significantly larger infarcts than female hearts, but methylphenidate had no impact on infarct size or postischemic recovery of contractile function in hearts of either sex. These data indicate that methylphenidate does not increase the extent of injury induced by an ischemic insult.

Effects of physical training on brain functional connectivity of methamphetamine dependencies as assessed using functional near-infrared spectroscopy

OBJECTIVE

This study aims to assess the effects of physical training based on the functional near-infrared spectroscopy (fNIRS) and heart rate signals.

METHODS

The oxygenated hemoglobin concentration (Delta [HbO₂]) signals were recorded from the left prefrontal cortex (LPFC), right prefrontal cortex (RPFC), left motor cortex (LMC) and right motor cortex (RMC) of 23 subjects with methamphetamine (METH) dependencies at resting, spinning training and strength training states. The wavelet phase coherence (WPCO) values were calculated in four frequency intervals: I, 0.6-2; II, 0.145-0.6; III, 0.052-0.145; and IV, 0.021-0.052 Hz. During the spinning training and strength training states, heart rate signals were recorded at 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 min, respectively.

RESULTS

After physical training, the brain regions of LPFC, RPFC and LMC showed different degrees of activation in the subjects with METH dependencies (p <  0.05). The WPCO values between the brain regions significantly altered after spinning training and strength training (p <  0.05) in frequency intervals I, II, III and IV.

CONCLUSIONS

The altered WPCO values indicated physical training could affect brain functional connectivity (FC) to a certain extent in the subjects with METH dependencies. These findings provide a method for the assessment of the effects of physical training in FC and will contribute to the development of drug rehabilitation methods in subjects with METH dependencies.

The epigenetic legacy of illicit drugs: developmental exposures and late-life phenotypes

The effects of in utero exposure to illicit drugs on adult offspring are a significant and widespread but understudied global health concern, particularly in light of the growing opioid epidemic and emerging therapeutic uses for cannabis, ketamine, and MDMA. Epigenetic mechanisms including DNA methylation, histone modifications, and expression of non-coding RNAs provide a mechanistic link between the prenatal environment and health consequences years beyond the original exposure, and shifts in the epigenome present in early life or adolescence can lead to disease states only appearing during adulthood. The current review summarizes the literature assessing effects of perinatal illicit drug exposure on adult disease phenotypes as mediated by perturbations of the epigenome. Both behavioral and somatic phenotypes are included and studies reporting clinical data in adult offspring, epigenetic readouts in offspring of any age, or both phenotypic and epigenetic measures are prioritized. Studies of licit substances of abuse (i.e. alcohol, nicotine) are excluded with a focus on cannabis, psychostimulants, opioids, and psychedelics; current issues in the field and areas of interest for further investigation are also discussed.

Myocardial hypersensitivity to ischemic injury is not reversed by clonidine or propranolol in a predator-based rat model of posttraumatic stress disorder

Individuals with posttraumatic stress disorder (PTSD) are at increased risk for cardiovascular disease. We previously reported that a predator-based model of PTSD increases myocardial sensitivity to ischemic injury. Heightened sympathetic signaling has a well-established role in the formation of anxiety associated with PTSD and may also contribute to worsening of myocardial injury in the ischemic heart. Thus, we examined whether suppression of sympathetic tone protects the ischemic heart in rats subjected to this model of PTSD. Rats were treated with saline or clonidine throughout the 31-day stress paradigm. Behavior on the elevated plus maze (EPM) was assessed on Day 32, and hearts were subjected to an ischemic insult on day 33. Stressed rats exhibited increased anxiety on the EPM and significantly larger myocardial infarcts following ischemia. Clonidine reversed the anxiety-like behavior but had no impact on infarct size. In a subsequent experiment, rats were treated with propranolol in their drinking water throughout the stress paradigm. Propranolol had no effect on either anxiety or myocardial sensitivity to ischemic injury. These findings suggest that the myocardial hypersensitivity to ischemic injury observed in this model is not caused by increased sympathetic tone or chronic β-adrenergic receptor signaling.

Gestational Hypoxia and Developmental Plasticity

Hypoxia is one of the most common and severe challenges to the maintenance of homeostasis. Oxygen sensing is a property of all tissues, and the response to hypoxia is multidimensional involving complicated intracellular networks concerned with the transduction of hypoxia-induced responses. Of all the stresses to which the fetus and newborn infant are subjected, perhaps the most important and clinically relevant is that of hypoxia. Hypoxia during gestation impacts both the mother and fetal development through interactions with an individual's genetic traits acquired over multiple generations by natural selection and changes in gene expression patterns by altering the epigenetic code. Changes in the epigenome determine "genomic plasticity," i.e., the ability of genes to be differentially expressed according to environmental cues. The genomic plasticity defined by epigenomic mechanisms including DNA methylation, histone modifications, and noncoding RNAs during development is the mechanistic substrate for phenotypic programming that determines physiological response and risk for healthy or deleterious outcomes. This review explores the impact of gestational hypoxia on maternal health and fetal development, and epigenetic mechanisms of developmental plasticity with emphasis on the uteroplacental circulation, heart development, cerebral circulation, pulmonary development, and the hypothalamic-pituitary-adrenal axis and adipose tissue. The complex molecular and epigenetic interactions that may impact an individual's physiology and developmental programming of health and disease later in life are discussed.

Repeated exposure to methamphetamine induces sex-dependent hypersensitivity to ischemic injury in the adult rat heart

Background

We previously reported that adult female, but not male rats that were prenatally exposed to methamphetamine exhibit myocardial hypersensitivity to ischemic injury. However, it is unknown whether hypersensitivity to ischemic injury develops when rats are exposed to methamphetamine during adulthood. The goal of this study was to determine whether methamphetamine exposure during adulthood sensitizes the heart to ischemic injury.

Methods

Adult male and female rats received daily injections of methamphetamine (5 mg/kg) or saline for 10 days. Their hearts were isolated on day 11 and subjected to a 20 min ischemic insult on a Langendorff isolated heart apparatus. Cardiac contractile function was measured by an intraventricular balloon, and infarct size was measured by triphenyltetrazolium chloride staining.

Results

Hearts from methamphetamine-treated females exhibited significantly larger infarcts and suppressed postischemic recovery of contractile function compared to hearts from saline-treated females. In contrast, methamphetamine had no effect on infarct size or contractile recovery in male hearts. Subsequent experiments demonstrated that hypersensitivity to ischemic injury persisted in female hearts following a 1 month period of abstinence from methamphetamine. Myocardial protein kinase C-ε expression, Akt phosphorylation, and ERK phosphorylation were unaffected by adult exposure to methamphetamine.

Conclusions

Exposure of adult rats to methamphetamine sex-dependently increases the extent of myocardial injury following an ischemic insult. These data suggest that women who have a heart attack might be at risk of more extensive myocardial injury if they have a recent history of methamphetamine abuse.

Differential behavioral effects of nicotine in adult male and female rats with a history of prenatal methamphetamine exposure

The goal of the current study was to assess the effects of prenatal methamphetamine (MA)/saline exposure on nicotine-induced stimulant and aversive effects in both male and female adult rats. The aversive effects of nicotine were assessed using the nicotine-induced conditioned taste aversion model (0.4mg/kg, base), while the stimulant effects of nicotine were measured by assessing changes in spontaneous locomotor activity after subcutaneous administration of different doses of nicotine (0, 0.1 & 0.4mg/kg, base). The aversive effects of nicotine were significantly decreased in male, but not in female rats with a history of prenatal MA exposure compared to respective saline controls. No influence of prenatal MA exposure was observed on nicotine-induced increase in locomotor activity in either male or female rats. In conclusion, males with a history of prenatal MA exposure may be more vulnerable to nicotine addiction due to a decrease in nicotine-induced aversive effects.

Sex-dependent effects of sleep deprivation on myocardial sensitivity to ischemic injury

Sleep deprivation is associated with increased risk of myocardial infarction. However, it is unknown whether the effects of sleep deprivation are limited to increasing the likelihood of experiencing a myocardial infarction or if sleep deprivation also increases the extent of myocardial injury. In this study, rats were deprived of paradoxical sleep for 96 h using the platform-over-water method. Control rats were subjected to the same condition except the control platform was large enough for the rats to sleep. Hearts from sleep deprived and control rats were subjected to 20 min ischemia on a Langendorff isolated heart system. Infarct size and post ischemic recovery of contractile function were unaffected by sleep deprivation in male hearts. In contrast, hearts from sleep-deprived females exhibited significantly larger infarcts than hearts from control females. Post ischemic recovery of rate pressure product and + dP/dT were significantly attenuated by sleep deprivation in female hearts, and post ischemic recovery of end diastolic pressure was significantly elevated in hearts from sleep deprived females compared to control females, indicating that post ischemic recovery of both systolic and diastolic function were worsened by sleep deprivation. These data provide evidence that sleep deprivation increases the extent of ischemia-induced injury in a sex-dependent manner.