Covassin, Naima

Abstract Cardiovascular disease (CVD) continues to be the leading cause of death in adults, highlighting the need to develop novel strategies to mitigate cardiovascular risk. The advancing obesity epidemic is now threatening the gains in CVD risk reduction brought about by contemporary pharmaceutical and surgical interventions. There are sex differences in the development and outcomes of CVD; premenopausal women have significantly lower CVD risk than men of the same age, but women lose this advantage as they transition to menopause, an observation suggesting potential role of sex hormones in determining CVD risk. Clear differences in obesity and regional fat distribution among men and women also exist. While men have relatively high fat in the abdominal area, women tend to distribute a larger proportion of their fat in the lower body. Considering that regional body fat distribution is an important CVD risk factor, differences in how men and women store their body fat may partly contribute to sex‐based alterations in CVD risk as well. This article presents findings related to the role of obesity and sex hormones in determining CVD risk. Evidence for the role of sex hormones in determining body composition in men and women is also presented. Lastly, the clinical potential for using sex hormones to alter body composition and reduce CVD risk is outlined. © 2022 American Physiological Society. Compr Physiol 12:1‐45, 2022.

Introduction: Adderall, the brand name for a combination of dextroamphetamine and amphetamine salts, is used to treat attention deficit disorder and narcolepsy, but is widely abused for improving cognitive function and alertness in absence of a medical indication. While little is known of its acute cardiovascular (CV) physiologic effects, Adderall has been linked to acute CV events (myocardial infarction, tachyarrhythmias, heart failure, Takotsubo cardiomyopathy and sudden death) and to long term CV consequences including hypertension and arterial disease. Aim: To examine the acute CV responses to Adderall in healthy subjects not on stimulant therapy in a randomized double-blind placebo-controlled crossover study. (CT.gov NCT02979327) Methods: Thirty subjects were randomized to 25 mg Adderall versus placebo. We measured supine resting blood pressure (BP), heart rate (HR), and plasma catecholamines, before and 3 hours after consuming Adderall or placebo. Results: Twenty-nine subjects (16 females; aged 25±5 yrs) completed both Adderall and placebo conditions, with a median of 10 days between visits. Systolic BP (SBP) increased from 112±10 mmHg to 127±11 mmHg after use of Adderall but was unchanged before vs after placebo drug intake (112±8 mmHg and 112±9 mmHg respectively; group by time interaction p<0.01). Diastolic BP and mean BP increased by 6.8 mmHg and 8.5 mmHg respectively and HR increased by 7.3 beats/min with Adderall, but they did not change with placebo (p<0.01). Plasma norepinephrine increased from 217±79 pg/ml before to 323±105 pg/ml after Adderall but was unchanged after placebo (p<0.05) (Figure 1). Conclusions: Healthy subjects consuming a modest dose of Adderall manifest striking increases in BP, HR and sympathetic activation, even during supine rest. These findings may have important mechanistic implications for understanding acute CV events and long-term risk of CV disease associated with stimulant medications.

Introduction: Sleep duration is now recognized as an important determinant of cardiovascular (CV) health. Recently, the CV implications of day-to-day variability in sleep duration have become apparent, with irregular sleep duration associated with increased risk of CV disease, including hypertension. However, the relationship between sleep duration variability and ambulatory blood pressure (BP) patterns in the general population or in patients with CV disease is unknown. Research Questions: We sought to investigate whether irregular sleep duration is associated with aberrant ambulatory BP or heart rate (HR) profiles in patients undergoing cardiac rehabilitation (CR). Methods: We recruited a sample of 42 patients with coronary artery disease enrolled in CR at Mayo Clinic Rochester. Participants underwent 24-hour ambulatory BP monitoring and sleep assessment including one week of wrist actigraphy and sleep diary prior to entering CR. Twenty-four hour, awake, and asleep averages were calculated for systolic BP, diastolic BP, and HR. Nocturnal dipping and morning surge were also computed for BP and HR. Sleep regularity was quantified by SD of actigraphy-derived sleep duration and irregular sleep duration was defined as SD >1 hour. Chi-square tests and Mann-Whitney U tests were used to compare groups. Results: Thirty-six participants (22% females, median age [25 th ,75 th IQR] 66.5 [61,75.8] years, body mass index 31.7 [26.9,35.1] kg/m 2 ) had valid actigraphy and ambulatory BP recordings. We found sleep duration SD >1 hour in 36% of them. Demographics and average sleep duration were similar between those with irregular and regular sleep duration (all Ps>0.11). Twenty-four-hour, awake and asleep HR values were comparable between groups (all Ps>0.26). Participants with irregular sleep duration exhibited lower nocturnal HR dipping (9.2 [3.1,11.6] % vs 12.9 [8.9,18.2] %, P=0.019) than their counterparts with regular sleep. Morning HR surge was also attenuated in patients with irregular sleep duration (3 [-1,9] bpm vs 10 [7,14] bpm, P=0.006). Ambulatory SBP and DBP measures did not differ significantly between groups (all Ps>0.17). Conclusions: High day-to-day variability in sleep duration is linked to blunted nocturnal dipping and morning surge in HR in patients with coronary artery disease enrolled in CR. Because altered ambulatory HR profile predicts unfavorable CV outcomes, evaluation of sleep patterns in the CR setting may yield important prognostic information.

Abstract Study Objectives The majority of patients with insomnia exhibit abnormal sleep in objective testing (e.g. decreased sleep duration, decreased slow wave sleep [SWS]). Previous studies have suggested that some of these objective measures of poor sleep, such as decreased sleep duration, are associated with a higher risk of hypertension in insomnia. We examined the relationship between SWS and morning and evening blood pressure (BP) levels in patients with clinically diagnosed insomnia. Methods A total of 229 normal sleepers and 1378 insomnia patients were included in this study. Insomnia was defined based on standard diagnostic criteria with symptoms lasting ≥6 months. All participants underwent in-laboratory polysomnography. Patients were classified into quartiles of percent SWS. Evening and morning hypertension were defined using BP measurements taken in the evening before and in the morning after polysomnography, respectively. Multivariable logistic regression models were used to assess the relationship between insomnia, SWS, and hypertension. Results Insomniacs with &lt;3.5% SWS (OR 3.27, 95% confidence intervals [CI]: 1.31 to 7.66) and those with 3.5%–10.2% SWS (OR 2.38, 95% CI: 1.28 to 5.91) had significantly greater odds of morning hypertension compared to normal sleepers. No associations were seen in insomnia with 10.2%–15.8% SWS and with &gt;15.8% SWS. Significant effect modifications by sex (p = .043) were found, as decreased SWS was associated with morning hypertension only in men. Odds of evening hypertension were not significantly associated with SWS. Conclusions Decreased SWS is associated with morning hypertension in a dose-dependent manner in insomnia, especially in men.

Abstract Purpose: Cardiovascular health disparities are present in African Americans, but it remains unknown whether this phenomenon affect Somali Americans. Study of Somali Americans is warranted due to distinct genetic and cultural differences from African Americans of western African ancestry. Orthostatic hemodynamic responses have implications for cardiovascular risk, especially among African American females. We sought to examine race and sex differences in systolic (SAP) and diastolic (DAP) arterial pressure and heart rate (HR) responsiveness to standing. We hypothesized that SAP, DAP, and HR change from supine to standing position would be higher in Somali Americans. Methods: We studied blood pressure and HR responsiveness in 139 (70 Somali; age: 29±10 years, 69 White; age: 31±9 years) participants. Supine SAP, DAP, and HR were measured after at least five minutes of supine rest, and again after one minute of standing. SAP, DAP, and HR change was compared between groups. Results: ΔSAP and ΔDAP were similar between groups (race × sex: p>0.05). However, HR responsiveness to orthostasis varied between race and sex comparisons (race×sex: p=0.011). Somali females exhibited an augmented HR response to orthostasis compared to White females (Δ19±13 vs. 11±9 beats/min, p=0.005) and Somali males (Δ19±13 vs. 12±9 beats/min, p=0.020). Conclusion: ΔHR to standing is augmented in young female Somali Americans. These findings highlight an early potential impairment in hemodynamic regulation that may heighten future cardiovascular risk. Further work is warranted to identify the potential autonomic nervous system underpinnings that may contribute to potentiated orthostatic responses and cardiovascular risk in Somali American females. Clinical Trial Registration: www.clinicaltrials.gov; unique identifier, NCT04124848; NCT05411029; NCT03308578.

Short sleep duration is associated with future cardiovascular disease including hypertension, especially in females, but mechanistic evidence is largely lacking. Experimental sleep restriction has been shown to cause short sleep-mediated tachycardia and reduced heart rate variability, indicative of autonomic cardiac instability, in some but not all studies. Heart rate (HR) response to spontaneous cortical arousals can be regarded as an index of autonomic cardiac control given its characteristic temporal pattern. Whether the HR response to cortical arousals is altered during experimental sleep restriction remains unknown. We hypothesized that sleep restriction would result in augmented HR reactivity to spontaneous arousals, and that this response would be more marked in females. We studied 19 young, healthy subjects (eight females, age: 23.5 ± 5 years, body mass index [BMI]: 24.5 ± 3.6 kg/m2). In a randomized, crossover design, participants were tested during a normal sleep (NS, 9 hr sleep opportunity) or sleep restriction (SR, 4 hr sleep opportunity) study arm. Each 16-day study visit consisted of a 4-day study acclimation phase, 9-day experimental sleep perturbation segment, followed by a 3-day recovery period. An overnight polysomnography (PSG) study was conducted on study days 2, 5 and 11 (at baseline and after 1 and 7 days of restricted versus control sleep). A registered PSG technician provided sleep staging and spontaneous arousal scoring, which was confirmed by an investigator with sleep expertise (IMG). For each identified spontaneous arousal, the HR change was quantified for 30 cardiac cycles post-arousal onset and compared to a pre-arousal baseline (average HR 5 – 10 cardiac cycles prior to arousal). An arousal was considered valid for analysis if at least one minute of stage N2 or rapid eye movement (REM) sleep occurred following sleep stage transition and was at least 30 seconds apart from other sleep disturbance-related events (e.g., limb movement, apneic event, etc.). Given low prevalence of slow wave sleep (SWS) arousals, arousals occurring in that sleep stage were excluded from present analysis. Statistical analysis, including repeated measures ANOVA (RMANOVA, p < 0.05) with condition and time (cardiac cycles) as within-subjects factors and sex as the between-subjects factor, was conducted to compare the beat-to-beat HR response to arousal between study conditions. Additionally, average and peak HR responses to spontaneous arousals were compared via RMANOVA with condition and time (study days) as within-subjects and sex as between-subjects factors. HR response to spontaneous arousal in stage two and REM sleep was similar between NS and SR on study day 5 or day 11 (condition × time: p = 0.943, 0.865). Secondary analysis of average and peak HR responsiveness to spontaneous arousals in stage two and REM sleep between conditions and study days was also not statistically different (condition × time: p = 0.193, 0.185). Last, no significant sex differences were detected across comparisons (condition × time × sex: p > 0.05 for all). These findings suggest that a 9-day sleep restriction paradigm may not alter cardiac autonomic function in otherwise healthy adults. Future work is warranted to determine whether these results extend to individuals with established cardiovascular risk factors or cardiovascular disease. Support: NIH T32-DK007013, R01-114676, and CTSA grant UL1-TR002377. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Introduction: The popularity of energy drinks among young adults is rising. Warnings have been issued regarding potential health risks including adverse cardiovascular complications. We and others have previously shown that energy drink consumption increases blood pressure. The mechanisms are not fully understood. Hypothesis: We hypothesized that increase in blood pressure after drinking a commercially available energy drink, compared to a placebo, is secondary to increased sympathetic activation. Methods: In a randomized, double-blind, placebo-controlled, cross-over study, we studied 25 healthy subjects, age 29±1 years, who were free of known disease, had no known cardiovascular risk factors, and were not on any medications. Each subject consumed a can, 16-fluid ounces, of Rockstar energy drink or a placebo drink in random order on two separate days. Blood pressure (n=25) and plasma norepinephrine levels (n=23) were measured before and 30-minutes after drink consumption. Results: Despite the increase in blood pressure after drinking Rockstar energy drink, which would be expected to elicit reflex reductions in central sympathetic outflow, plasma norepinephrine levels increased markedly after energy drink consumption vs placebo (73.6±9.7% vs 30.9±9.7%, respectively, P=0.003; Figure). Specifically, plasma norepinephrine levels increased from 149.8±11.7pg/ml to 249.8±17.3pg/ml after the energy drink consumption and from 139.9±11.7pg/ml to 178.6±17.3pg/ml after placebo (P=0.0007 for timeхtreatment comparison). Conclusions: Increased blood pressure after consumption of commercially available energy drink is associated with significantly increased catecholamine levels in young healthy adults. These acute hemodynamic and adrenergic changes may predispose to increased cardiovascular risk by triggering arrhythmias or ischemia, particularly in individuals with a vulnerable cardiovascular substrate.

Background Although cardiovascular mortality continued declining from 2000 to 2019, the rate of this decrease decelerated. We aimed to assess the trends and disparities in risk factor control and treatment among US adults with atherosclerotic cardiovascular disease to find potential causes of the deceleration. Methods and Results A total of 55 ,021 participants, aged ≥20 years, from the 1999 to 2018 National Health and Nutrition Examination Survey were included, of which 5717 were with atherosclerotic cardiovascular disease. Risk factor control was defined as hemoglobin A1c <7%, blood pressure <140/90 mm Hg, and non–high‐density lipoprotein cholesterol <100 mg/dL. The prevalence of atherosclerotic cardiovascular disease oscillated between 7.3% and 8.9% from 1999 to 2018. A significant increasing trend was observed in the prevalence of diabetes, obesity, heavy alcohol consumption, and self‐reported hypertension within the population with atherosclerotic cardiovascular disease ( P trend ≤0.001). Non–high‐density lipoprotein cholesterol <100 mg/dL increased from 7.1% in 1999 to 2002 to 15.7% in 2003 to 2006, before plateauing. Blood pressure control (<140/90 mm Hg) increased until 2011 to 2014, but declined to 70.1% in 2015 to 2018 ( P trend <0.001, P joinpoint =0.14). Similarly, the proportion of participants achieving hemoglobin A1c control began to decrease after 2006 ( P joinpoint =0.05, P trend =0.001). The percentage of participants achieving all 3 targets increased significantly from 4.5% to 18.6% across 1999 to 2018 ( P trend =0.02), but the increasing trend decelerated after 2005 to 2006 ( P joinpoint <0.001). Striking disparities in risk factor control and medication use persisted between sexes, and between different racial and ethnic populations. Conclusions Worsened control of glycemia, blood pressure, obesity, and alcohol consumption, leveled lipid control, and persistent socioeconomic disparities may be contributing factors to the observed deceleration in decreasing cardiovascular mortality trends.

Background Decreases in estrogen are shown to increase body fat in men. However, obese men have high levels of estrogen and the effects of weight gain on estrogen have not been previously investigated. The objective of this study was to investigate the relationship between regional fat depots and estrogen during modest weight in healthy men. Methods We investigated the effects of overfeeding in 25 healthy men (30 ± 7 years, 24.7 ± 3.1 kg/m 2 ). Changes in regional fat depot during weight gain were assessed using dual‐energy X‐ray absorptiometry and abdominal computed tomography scans. Participants gained approximately 5% body weight in 8 weeks. Estrone (E1), 17β‐estradiol (E2) and sex hormone binding globulin (SHBG) were measured at baseline and after weight gain. Results Overfeeding was accompanied by 3.9 ± 1.3 kg weight gain. These increases in weight resulted from increases in total body fat mass (18.3 ± 8.5 vs. 21.7 ± 8.8 kg, p<0.001) while the fat free mass did not change (58.4 ± 8.6 vs. 58.9 ± 8.7 kg, p=0.15). E1 (32.28 ± 14.25 vs. 33.44 ± 12.29 pg/mL, p=0.56) and E2 (25.04 ± 8.3 vs. 26.52 ± 7.8 pg/mL, p=0.28) did not change after weight gain. However, weight gain resulted in decreased SHBG (22.8 ± 10.5 vs. 20.8 ± 11.1 nmol/l, p=0.036) and increased E2/SHBG ratio (1.4 ± 1.0 vs 1.63 ± 1.0, p=0.027). The changes in E2/SHBG ratio, a surrogate marker of bioavailable E2, was positively associated with increases in abdominal fat mass (p=0.048, rho=0.39) and increases in visceral fat mass (p=0.049, rho=0.39). Conclusion Modest weight gain in healthy men does not alter circulating E1 and E2 levels. However weight gain results in decreased SHBG and increased free E2 (E2/SHBG ratio). The increased E2/SHBG ratio suggesting a pro‐estrogen effect is associated with increases in visceral fat mass during weight gain. Our study therefore suggests a complex relationship between abdominal fat gain and free E2 in men which may conceivably predispose to feminizing characteristics in obese men. Support or Funding Information PS is supported by AHA Grant 11SDG7260046 and NIH grant DK81014. NC is supported by AHA grant AHA 13POST16420009. MDJ is supported by NIH grants DK45343 and DK40484. VKS is supported by NIH Grants HL73211, and DK81014. This study was made possible by a grant from NCRR (1UL1 RR024150).