The Role of Heart Rate Variability in Mindfulness-Based Pain Relief

Mindfulness meditation is a self-regulatory practice premised on sustaining nonreactive awareness of arising sensory events that reliably reduces pain. Yet, the specific analgesic mechanisms supporting mindfulness have not been comprehensively disentangled from the potential nonspecific factors supporting this technique. Increased parasympathetic nervous system (PNS) activity is associated with pain relief corresponding to a number of cognitive manipulations. However, the relationship between the PNS and mindfulness-based pain attenuation remains unknown. The primary objective of the present study was to determine the role of high-frequency heart rate variability (HF HRV), a marker of PNS activity, during mindfulness-based pain relief as compared to a validated, sham-mindfulness meditation technique that served as a breathing-based control. Sixty-two healthy volunteers (31 females; 31 males) were randomized to a 4-session (25 min/session) mindfulness or sham-mindfulness training regimen. Before and after each group's respective training, participants were administered noxious (49°C) and innocuous (35°C) heat to the right calf. HF HRV and respiration rate were recorded during thermal stimulation and pain intensity and unpleasantness ratings were collected after each stimulation series. The primary analysis revealed that during mindfulness meditation, higher HF HRV was more strongly associated with lower pain unpleasantness ratings when compared to sham-mindfulness meditation (B = -.82, P = .04). This finding is in line with the prediction that mindfulness-based meditation engages distinct mechanisms from sham-mindfulness meditation to reduce pain. However, the same prediction was not confirmed for pain intensity ratings (B = -.41). Secondary analyses determined that mindfulness and sham-mindfulness meditation similarly reduced pain ratings, decreased respiration rate, and increased HF HRV (between group ps < .05). More mechanistic work is needed to reliably determine the role of parasympathetic activation in mindfulness-based pain relief as compared to other meditative techniques. Perspective: Mindfulness has been shown to engage multiple mechanisms to reduce pain. The present study extends on this work to show that higher HRV is associated with mindfulness-induced reductions in pain unpleasantness, but not pain intensity ratings, when compared to sham-mindfulness meditation. These findings warrant further investigation into the mechanisms engaged by mindfulness as compared to placebo.

Children with orthostatic intolerance exhibit elevated markers of inflammation in the dorsal medulla

Children with orthostatic intolerance (OI) have exaggerated decreases in heart rate variability (HRV) and suppression of baroreflex sensitivity (BRS) with standing. Accompanying brain transmitter and metabolite profiles are unknown. In this study, we used proton (¹H) magnetic resonance spectroscopy (¹H-MRS) to quantify markers of neuronal and glial integrity in a pilot study of children with OI compared with asymptomatic controls. Eighteen participants ages 10-18 yr were evaluated for blood pressure, heart rate (HR), and calculated indexes of autonomic function in supine and upright positions and, within an average of 2 wk, underwent ¹H-MRS scans of dorsal medulla on a clinical 3T magnet while supine. As a result, of the 18 participants, 11 tested positive for OI and 7 did not. OI subjects exhibited higher HR and lower HRV and high-frequency α-index (HFα), an index of parasympathetic vagal tone, during standing compared with non-OI. HRV, sequence all (Seq All), high- and low-frequency (HFα and LFα) estimates of the spontaneous BRS decreased significantly, while BP variabilty increased significantly during standing only in subjects with OI. OI subjects had higher myoinositol (mIns) and total choline (tCho), markers of glial inflammation. Upright HFα and Seq All inversely correlated to supine tCho and mIns, respectively, independent of age and sex. In conclusions, in this pilot study, children with OI exhibit higher mIns and tCho in the dorsal medulla while supine that may reflect the well-established impairment in regulation of the autonomic nervous system upon standing. Neuroinflammation as an underlying cause or consequence of autonomic dysfunction is an intriguing possibility requiring further study.NEW & NOTEWORTHY (¹H) magnetic resonance spectroscopy detected elevated markers of neuroinflammation in the dorsal medulla in children with impaired autonomic responses to head upright tilt. This first report of altered brain metabolites in this population provides a basis for future clinical studies using this methodology to aide in understanding complex autonomic disease states.

Central ANG-(1-7) infusion improves blood pressure regulation in antenatal betamethasone-exposed sheep and reveals sex-dependent effects on oxidative stress

Fetal exposure to betamethasone (BMX) as a consequence of glucocorticoid administration to women threatening premature delivery may lead to long-term deleterious effects on the cardiovascular system and dysregulation of blood pressure in exposed adults. Indeed, adult offspring of BMX sheep exhibit increased mean arterial pressure (MAP) and attenuated baroreflex sensitivity (BRS) that are associated with lower medullary and cerebrospinal fluid (CSF) angiotensin-(1-7) [(ANG-(1-7)] content. Thus we determined the effects of ANG-(1-7) supplementation in the CSF on MAP, BRS, blood pressure (BPV) and heart rate variability (HRV) in conscious animals. The peptide or artificial CSF (aCSF) was infused continuously into the lateral ventricle (intracerebroventricular) of 4-mo-old male and female BMX sheep for 2 wk. Analysis of data from males and females combined revealed that intracerebroventricular ANG-(1-7) significantly lowered MAP and heart rate and improved BRS as compared with baseline; intracerebroventricular aCSF did not change these indexes. Similar patterns were observed for altered hemodynamics and autonomic function produced by intracerebroventricular ANG-(1-7) in both sexes. Oxidative stress and MAP kinase (MAPK) activation were lower in tissues from the dorsomedial medulla (DMM) of ANG-(1-7)-treated males but were unchanged in the treated females, when assessed at the end of the treatment period. We conclude that in the face of ANG-(1-7) deficiency in CSF and medullary tissue in BMX sheep intracerebroventricular supplementation of ANG-(1-7) lowers MAP and restores the impaired autonomic function to a similar degree in both males and females; however, the attenuation of MAPK and oxidative stress within the DMM was evident only in males. NEW & NOTEWORTHY We demonstrate that intracerebroventricular angiotensin-(1-7) [(ANG-(1-7)] treatment for 2 wk in antenatal betamethasone-exposed sheep provides beneficial effects on blood pressure and autonomic function. The physiological improvements are accompanied by an attenuation of oxidative stress in males but not females. The finding that ANG-(1-7) supplementation lowers blood pressure and restores the impaired autonomic function in a model of fetal programming previously shown to exhibit a deficiency in cerebrospinal fluid and brain tissue illustrates the potential for new therapeutic strategies for reducing cardiovascular dysfunction arising from prenatal events.

Obesity is Associated with Higher Blood Pressure and Higher Levels of Angiotensin II but Lower Angiotensin-(1-7) in Adolescents Born Preterm

OBJECTIVES

To evaluate if obesity is associated with increased angiotensin II (Ang II) and decreased angiotensin-(1-7) or Ang-(1-7) in the circulation and urine among adolescents born prematurely.

STUDY DESIGN

In a cross-sectional analysis of 175 14-year-olds born preterm with very low birth weight, we quantified plasma and urinary Ang II and Ang-(1-7) and compared their levels between subjects with overweight/obesity (body mass index ≥85th percentile, n = 61) and those with body mass index <85th percentile (n = 114) using generalized linear models, adjusted for race and antenatal corticosteroid exposure.

RESULTS

Overweight/obesity was associated with higher systolic blood pressure and a greater proportion with high blood pressure. After adjustment for confounders, overweight/obesity was associated with an elevated ratio of plasma Ang II to Ang-(1-7) (β: 0.57, 95% CI 0.23-0.91) and higher Ang II (β: 0.21 pmol/L, 95% CI 0.03-0.39) but lower Ang-(1-7) (β: -0.37 pmol/L, 95% CI -0.7 to -0.04). Overweight/obesity was associated with a higher ratio of urinary Ang II to Ang-(1-7) (β: 0.21, 95% CI -0.02 to 0.44), an effect that approached statistical significance.

CONCLUSIONS

Among preterm-born adolescents, overweight/obesity was associated with increased Ang II but reduced Ang-(1-7) in the circulation and the kidney as well as higher blood pressure. Obesity may compound the increased risk of hypertension and cardiovascular disease in individuals born prematurely by further augmenting the prematurity-associated imbalance in the renin-angiotensin system.

Fetal programming and the angiotensin-(1-7) axis: a review of the experimental and clinical data

Hypertension is the primary risk factor for cardiovascular disease that constitutes a serious worldwide health concern and a significant healthcare burden. As the majority of hypertension has an unknown etiology, considerable research efforts in both experimental models and human cohorts has focused on the premise that alterations in the fetal and perinatal environment are key factors in the development of hypertension in children and adults. The exact mechanisms of how fetal programming events increase the risk of hypertension and cardiovascular disease are not fully elaborated; however, the focus on alterations in the biochemical components and functional aspects of the renin-angiotensin (Ang) system (RAS) has predominated, particularly activation of the Ang-converting enzyme (ACE)-Ang II-Ang type 1 receptor (AT1R) axis. The emerging view of alternative pathways within the RAS that may functionally antagonize the Ang II axis raise the possibility that programming events also target the non-classical components of the RAS as an additional mechanism contributing to the development and progression of hypertension. In the current review, we evaluate the potential role of the ACE2-Ang-(1-7)-Mas receptor (MasR) axis of the RAS in fetal programming events and cardiovascular and renal dysfunction. Specifically, the review examines the impact of fetal programming on the Ang-(1-7) axis within the circulation, kidney, and brain such that the loss of Ang-(1-7) expression or tone, contributes to the chronic dysregulation of blood pressure (BP) and cardiometabolic disease in the offspring, as well as the influence of sex on potential programming of this pathway.

Renal function and blood pressure are altered in adolescents born preterm

BACKGROUND

Preterm birth increases the risk of hypertension and kidney disease. However, it is unclear when changes in blood pressure (BP) and renal function become apparent and what role obesity and sex play. We hypothesized adolescents born preterm have higher BP and worse kidney function compared to term in an obesity- and sex-dependent manner.

METHODS

Cross-sectional analysis of 14-year-olds born preterm with very low birth weight (n = 96) compared to term (n = 43). We used generalized linear models to estimate the associations among preterm birth and BP, estimated glomerular filtration rate (eGFR), and ln (x) urinary albumin-to-creatinine ratio (ACR), stratified by overweight/obesity (OWO, body mass index (BMI) ≥ 85th percentile) and sex.

RESULTS

Compared to term, preterm-born adolescents had higher systolic blood pressure (SBP) and diastolic blood pressure (DBP) (adjusted β (aβ) 3.5 mmHg, 95% CI - 0.1 to 7.2 and 3.6 mmHg, 95% CI 0.1 to 7.0), lower eGFR (β - 8.2 mL/min/1.73 m², 95% CI - 15.9 to - 0.4), and higher ACR (aβ 0.34, 95% CI - 0.04 to 0.72). OWO modified the preterm-term difference in DBP (BMI < 85th percentile aβ 5.0 mmHg, 95% CI 0.7 to 9.2 vs. OWO 0.2 mmHg, 95% CI - 5.3 to 5.6) and ACR (OWO aβ 0.72, 95% CI 0.15 to 1.29 vs. BMI < 85th percentile 0.17, 95% CI - 0.31 to 0.65). Sex modified the preterm-term ACR difference (female aβ 0.52, 95% CI 0.001 to 1.04 vs. male 0.18, 95% CI - 0.36 to 0.72).

CONCLUSIONS

Prematurity was associated with higher BP and reduced renal function that were detectable in adolescence. OWO and sex may modify the strength of these relationships.

Chronic nausea and orthostatic intolerance: Diagnostic utility of orthostatic challenge duration, Nausea Profile Questionnaire, and neurohumoral measures

BACKGROUND

Chronic nausea in pediatrics is a debilitating condition with unclear etiology. We aimed to define hemodynamic and neurohumoral characteristics of chronic nausea associated with orthostatic intolerance in order to improve identification and elucidate mechanism.

METHODS

Children (10-18 years) meeting Rome III criteria for functional dyspepsia with nausea and symptoms of orthostatic intolerance (OI) completed a Nausea Profile Questionnaire followed by prolonged (45 minutes rather than the traditional 10 minutes) head-upright tilt (HUT) (70° tilt up) test. Circulating catecholamines, vasopressin, aldosterone, renin, and angiotensins were measured supine and after 15 minutes into HUT. Beat-to-beat heart rate and blood pressure were continuously recorded to calculate their variability and baroreflex sensitivity.

KEY RESULTS

Within 10 and 45 minutes of HUT, 46% and 85% of subjects, respectively, had an abnormal tilt test (orthostatic hypotension, postural orthostatic tachycardia, or syncope). At 15 and 45 minutes of HUT, nausea was elicited in 42% and 65% of subjects respectively. Higher Nausea Profile Questionnaire scores correlated with positive HUT testing at 10 minutes (P = 0.004) and baroreflex sensitivity at 15 minutes (P ≤ 0.01). Plasma vasopressin rose 33-fold in subjects with HUT-induced nausea compared to twofold in those who did not experience HUT-induced nausea (P < 0.01).

CONCLUSIONS AND INFERENCES

In children with chronic nausea and OI, longer duration HUT elicited higher frequency of abnormal tilt testing and orthostatic-induced nausea. The Nausea Profile Questionnaire predicted the orthostatic response to tilt testing. Exaggerated vasopressin release differentiated patients with HUT-induced nausea (vs those without nausea), suggesting a possible mechanism for chronic nausea in childhood.

Abstract P306: Preterm Birth is Associated with Increased Blood Pressure and Increased Urinary Angiotensinogen in Young Adults

Introduction: Cardiovascular disease (CVD) is the leading cause of mortality and hypertension (HTN) is a major risk factor for CVD. Preterm birth is an emerging risk factor for both CVD and HTN, but the underlying mechanisms are poorly described. The renin-angiotensin system (RAS) plays a key role in HTN and CVD, and adolescents born preterm have higher blood pressure (BP) with a shift in the balance of the classical and alternative pathways of the RAS exhibited as increased angiotensin II and reduced angiotensin-(1-7) as compared to term-born adolescents. Although numerous factors influence the expression of angiotensins, the precursor protein angiotensinogen in the kidney is implicated in the development of HTN and CVD and may contribute to higher angiotensin II. As the status of renal angiotensinogen in individuals born preterm is unknown, we hypothesized that urinary angiotensinogen is increased in young adults born preterm as compared to their term-born peers.

Methods: We compared urinary excretion of angiotensinogen corrected for urine creatinine and systolic and diastolic BP in 142 young adults (mean age 19.9 years) born preterm with very low birth weight (<1500 g) to 32 young adults born term using Wilcoxon Rank-Sum test and t-test. We used generalized linear models to compare the ln(x) urinary angiotensinogen between the preterm and term groups adjusted for the potentially confounding factors race, maternal hypertensive pregnancy, and maternal smoking during pregnancy.

Results: Compared to term, subjects born preterm had higher median urinary angiotensinogen (0.02 μg/g, IQR 0.01 to 0.04 vs. 0.01 μg/g, IQR 0.004 to 0.01, p < 0.001) and higher mean systolic BP (111 mmHg, SD 11 vs. 106 mmHg, SD 10, p = 0.03). On crude and adjusted analyses urinary angiotensinogen was associated positively with preterm birth (crude β : 0.82, 95% CI 0.47 to 1.16; adjusted β : 0.79, 95% CI 0.39 to 1.18).

Discussion: In addition to higher BP, young adults born preterm demonstrated increased urinary angiotensinogen as compared to their term-born peers. Preterm birth may induce programming of the renal RAS leading to higher angiotensinogen and a higher angiotensin-to-angiotensin-(1-7) ratio, potentially contributing to the increased risk of HTN in individuals born preterm.

Abstract P396: Vitamin D Supplementation Improves Cardiovascular Response to Head Up Tilt in Adolescents Suffering from Syncope

Background: In previous work we identified a group of adolescents whose diagnostic workup for chronic unexplained nausea revealed underlying cardiovascular instability manifesting as orthostatic intolerance (OI) and syncope. These patients exhibited impairment in autonomic function and excessive release of catecholamines (Epi / NE) and vasopressin (AVP) upon head up tilt compared to pre tilt. They also had low vitamin D level that correlated with the severity of symptoms on tilt. In this pilot study we hypothesized that vitamin D supplementation to normal levels will improve the cardiovascular response to tilt and reduce NE/Epi and AVP release.

Methods: A cohort of seven Adolescents (mean age= 16.2 years) who are vitamin D deficient had a head up tilt at baseline and after two months of vitamin D supplementation (2000-5000 IU daily based on baseline level). Heart rate, blood pressure, NE/Epi and AVP were measured in supine and standing position. Total time on tilt was also recorded.

Results: As see in the table. Compared to baseline, vitamin D supplementation reduced the HR elevation post HUT and reduced NE/Epi baseline levels and ameliorated the elevation in AVP after HUT.

Conclusions: Vitamin D supplementation for two months restored vitamin D to normal levels and was associated with less nausea symptoms during tilt and lower level of baseline catecholamines. It was also associated with less release of NE/Epi and vasopressin post head up tilt and longer duration of standing on tilt table. These data provides evidence of potential therapeutic benefit of vitamin D supplementation for patients suffering from syncope who are vitamin D deficient

Abstract 135: Impaired Autonomic Function in Young Adults Born Preterm With Very Low Birth Weight is Associated With Elevated Serum Uric Acid Levels

Preterm birth increases the risk of cardiometabolic disease. We showed that prematurity induces programming effects that lead to elevated blood pressure (BP), higher serum uric acid, and impaired autonomic control characterized by reduced heart rate variability (HRV), baroreflex sensitivity (BRS), and elevated ratio of low frequency to high frequency power (LF/HF), a marker of sympathovagal balance. However, the relationships among these factors in subjects born preterm are undefined. Since uric acid has been shown to correlate with HRV in adult hypertensive subjects, we hypothesized that higher uric acid is associated with impaired autonomic function in subjects born preterm.

Methods: A cohort of 131 young adults born preterm was compared to a cohort of 26 born term (19.6 years). Serum uric acid was measured. BP and ECG were recorded continuously for analysis of autonomic function reflected in HRV and BRS. We used generalized linear models to estimate the association between uric acid and measures of HRV and BRS, adjusting for race, age at follow up, and BMI. The potential interaction between uric acid and preterm birth was tested by introducing an interaction term and, if suggestive of an interaction (p ≤ 0.1), estimates were calculated within strata (preterm & term).

Results: Compared to term, preterm participants had higher serum uric acid levels (5.2 mg/dL, IQR: 4.2, 6.2 vs 4.8 mg/dL, IQR: 3.9, 6.0) and lower HRV as measured by standard deviation of normal to normal RR intervals (71 ms, IQR: 54, 97 vs 80 ms, IQR: 55, 101). Across term and preterm groups combined, uric acid was inversely associated with BRS measured as HF alpha ( β : -0.12, 95% CI -0.20 to -0.03, p for interaction = 0.06). Assessment of interaction showed this association was significant in preterms only ( β : -0.15, 95% CI -0.24 to -0.06 vs 0.07, -0.17 to 0.30). Uric acid was positively associated with LF/HF ( β : 0.13, 95% CI 0.01 to 0.25, p for interaction=0.01).

Conclusions: Young adults born preterm had dampened parasympathetic control of heart rate and BP, and higher serum uric acid was associated with sympathovagal imbalance. The data suggest that alterations of uric acid metabolism associated with preterm birth may increase the risk of early cardiovascular disease in part by impairing autonomic control

Abstract P301: Heart Rate Variability is Associated with Future Global Cognitive Performance: the Multi-Ethnic Study of Atherosclerosis

Background: Low heart rate variability (HRV) is associated with major vascular risk factors for cognitive decline, including hypertension and cardiovascular disease (CVD). Therefore, we hypothesized that higher HRV during mid- to late-life is associated with better cognitive performance.

Methods: In a subset of participants from the Multi-Ethnic Study of Atherosclerosis (N = 2,961; aged 45-84 years; 55% female; 40% white, 22% African-American, 25% Hispanic, and 13% Chinese-American), we used multivariate linear regression to study the relationship of short-term HRV to global cognitive performance as measured by the Cognitive Abilities Screening Instrument (CASI; score range 0-100). Two measures of HRV, the standard deviation of normal-to-normal intervals (SDNN) and root mean square of successive differences (RMSSD), were computed at Exam 1 (2000-2002) and Exam 5 (2010-2012). CASI was administered at Exam 5.

Results: In age-, race-, sex- and education-adjusted models, Exam 1 SDNN was significantly associated with performance on the CASI ( β = 0.74 ± 0.22; P < 0.001). This association remained significant after adjustment for cardiovascular risk factors, including prevalent CVD, medication use, and APOE ε4 allele carriage ( β = 0.53 ± 0.23; P = 0.019). Furthermore, participants with highest quartile Exam 1 SDNN scored better than the adjusted mean CASI score (0.61 ± 0.22 points higher; P = 0.022), and 0.81 ± 0.29 points higher than other quartiles ( P = 0.006); participants in other Exam 1 SDNN quartiles scored similarly to each other and to the adjusted mean. In contrast, there were no associations between CASI score and Exam 5 SDNN, Exam 1 RMSSD, or Exam 5 RMSSD after adjustment for cardiovascular risk factors, and no interactions between HRV and race or APOE were present.

Conclusions: Highest quartile 10-year antecedent SDNN is associated with better global cognitive performance in a multi-ethnic population of middle-aged and elderly adults, independent of sociodemographic factors, traditional cardiovascular risk factors, APOE status, and prevalent CVD. These results suggest that mid- to late-life HRV may be an early predictor of future cognitive ability.

Improvements in Heart Rate Variability, Baroreflex Sensitivity, and Sleep After Use of Closed-Loop Allostatic Neurotechnology by a Heterogeneous Cohort

Background

Heart rate variability (HRV) is an indicator of dynamic adaptability of the autonomic nervous system. Few interventions target upstream, cerebral cortex components of the heart–brain system for autonomic management. We report changes in HRV and baroreflex sensitivity (BRS), associated with use of a noninvasive, closed-loop, allostatic, computer-guided, acoustic stimulation neurotechnology.

Methods

Over 5 years, 220 subjects with heterogeneous neurological, cardiovascular, and psychophysiological conditions consecutively enrolled in a naturalistic, single-arm study exploring clinical effects associated with use of the neurotechnology. Of those, 202 completed the study protocol and 160 had recordings adequate to analyze HRV and BRS. Mean age was 44.0 (SD 19.4), with 130 women. Participants received a mean of 16.1 (5.2) sessions, over 24.2 days (23.3), with 9.5 (3.8) actual intervention days. Sessions included real-time analysis of brain electrical activity and software algorithm-guided translation of selected frequencies into patterns of acoustic stimulation (audible tones of variable pitch and timing), to facilitate auto-calibration of neural oscillations. Outcomes including 10-min supine, at-rest recordings of blood pressure and heart rate, and inventories for insomnia (ISI) and depression (CES-D or BDI-II), were obtained at baseline and 15.3 (16.7) days after the last session.

Results

Compared to baseline, significant increases (all p < 0.001) were observed for measures of HRV across all participants including the mean percentage change for SDNN 24.2% (SE 0.04), and RMSSD, 42.2% (0.08), and BRS [Sequence Up, 55.5% (0.09), Sequence Down, 77.6% (0.23), and Sequence All, 53.7% (0.07)]. Significant improvements were noted in SAP, MAP, and DAP, as well as natural log of HF, and total power. Self-reported ISI was reduced (ISI, −6.4 points, SD 5.6, p < 0.001). The proportion reporting clinically significant depressive symptoms reduced from 48.2% at baseline to 22.1% at follow-up. Linear regression showed that rightward asymmetry predicted lower SDNN (p = 0.02). Exploratory analysis showed a trend for improved balance of temporal lobe high-frequency amplitudes over the course of initial sessions.

Conclusion

These findings indicate that use of a noninvasive, allostatic, closed-loop neurotechnology appears to have robust potential for public health efforts to support greater flexibility in autonomic cardiovascular regulation, through self-optimization of electrical activity at the level of the brain.

Successful use of closed-loop allostatic neurotechnology for post-traumatic stress symptoms in military personnel: self-reported and autonomic improvements

BACKGROUND

Military-related post-traumatic stress (PTS) is associated with numerous symptom clusters and diminished autonomic cardiovascular regulation. High-resolution, relational, resonance-based, electroencephalic mirroring (HIRREM®) is a noninvasive, closed-loop, allostatic, acoustic stimulation neurotechnology that produces real-time translation of dominant brain frequencies into audible tones of variable pitch and timing to support the auto-calibration of neural oscillations. We report clinical, autonomic, and functional effects after the use of HIRREM® for symptoms of military-related PTS.

METHODS

Eighteen service members or recent veterans (15 active-duty, 3 veterans, most from special operations, 1 female), with a mean age of 40.9 (SD = 6.9) years and symptoms of PTS lasting from 1 to 25 years, undertook 19.5 (SD = 1.1) sessions over 12 days. Inventories for symptoms of PTS (Posttraumatic Stress Disorder Checklist - Military version, PCL-M), insomnia (Insomnia Severity Index, ISI), depression (Center for Epidemiologic Studies Depression Scale, CES-D), and anxiety (Generalized Anxiety Disorder 7-item scale, GAD-7) were collected before (Visit 1, V1), immediately after (Visit 2, V2), and at 1 month (Visit 3, V3), 3 (Visit 4, V4), and 6 (Visit 5, V5) months after intervention completion. Other measures only taken at V1 and V2 included blood pressure and heart rate recordings to analyze heart rate variability (HRV) and baroreflex sensitivity (BRS), functional performance (reaction and grip strength) testing, blood and saliva for biomarkers of stress and inflammation, and blood for epigenetic testing. Paired t-tests, Wilcoxon signed-rank tests, and a repeated-measures ANOVA were performed.

RESULTS

Clinically relevant, significant reductions in all symptom scores were observed at V2, with durability through V5. There were significant improvements in multiple measures of HRV and BRS [Standard deviation of the normal beat to normal beat interval (SDNN), root mean square of the successive differences (rMSSD), high frequency (HF), low frequency (LF), and total power, HF alpha, sequence all, and systolic, diastolic and mean arterial pressure] as well as reaction testing. Trends were seen for improved grip strength and a reduction in C-Reactive Protein (CRP), Angiotensin II to Angiotensin 1-7 ratio and Interleukin-10, with no change in DNA n-methylation. There were no dropouts or adverse events reported.

CONCLUSIONS

Service members or veterans showed reductions in symptomatology of PTS, insomnia, depressive mood, and anxiety that were durable through 6 months after the use of a closed-loop allostatic neurotechnology for the auto-calibration of neural oscillations. This study is the first to report increased HRV or BRS after the use of an intervention for service members or veterans with PTS. Ongoing investigations are strongly warranted.

TRIAL REGISTRATION

NCT03230890 , retrospectively registered July 25, 2017.

Antenatal corticosteroids and cardiometabolic outcomes in adolescents born with very low birth weight

BackgroundExposure to antenatal corticosteroids (ANCS) is associated with adverse cardiometabolic outcomes in animal models; however, long-term outcomes in clinical studies are not well characterized. We hypothesized that exposure to ANCS would be associated with markers of increased cardiometabolic risk in adolescents born with very low birth weight (VLBW).MethodsIn an observational cohort of 186 14-year-old adolescents born with VLBW, we measured resting blood pressure (BP), BP response to cold, ambulatory BP, and anthropometrics; performed dual-energy X-ray absorptiometry; and analyzed blood samples for uric acid, cholesterol, glycated hemoglobin, and high-sensitivity C-reactive protein. Multivariate analyses were used to evaluate associations with ANCS, adjusting for race, sex, and maternal hypertensive pregnancy.ResultsThere were no ANCS group differences in BP measures or blood biomarkers. Compared with adolescents unexposed to ANCS, those exposed to ANCS were taller (exposed-unexposed mean difference 3.1 cm (95% confidence interval (CI) 0.7, 5.5)) and had decreased waist-to-height ratio (exposed-unexposed mean difference -0.03 (95% CI -0.058, -0.002)). Males exposed to ANCS had lower total cholesterol (exposed-unexposed mean difference -0.54 mmol/l (95%CI -0.83, -0.06)).ConclusionAmong adolescents born with VLBW, ANCS exposure was not associated with markers of increased cardiometabolic risk.

Abstract P484: Improved Heart Rate Variability, and Symptoms of Insomnia and Stress, With Use of a Closed-loop, Allostatic Neurotechnology in Law Enforcement Officers

Background: Law enforcement officers have decreased life expectancy, attributed to work-related exposure to traumatic stress and circadian disruption. Autonomic dysregulation is reported with traumatic stress, and chronic insomnia. Closed-loop therapies with real time monitoring for modulation of biological function offer a precision-guided, patient-centric strategy for brain-based therapies. High-resolution, relational, resonance-based, electroencephalic mirroring (HIRREM®) is a noninvasive, closed-loop, allostatic, acoustic stimulation neurotechnology using software generated algorithms to identify specific brain frequencies, and translate them in real time into audible tones, to support self-optimization of brain rhythms.

Objective: To evaluate benefits for autonomic function, and symptoms of insomnia and stress, in a relatively healthy cohort of law enforcement officers, who enrolled in an IRB-approved, open label feasibility study evaluating HIRREM for diverse neuropsychological disorders. Measures done before and after HIRREM included symptom inventories for insomnia (ISI), depression (CES-D), traumatic stress (PCL-C), anxiety (GAD-7), and perceived stress (PSS). Ten minute recordings of heart rate and blood pressure allowed analysis of baroreflex sensitivity (BRS) and heart rate variability (HRV).

Results: 7 participants (1 female), mean (SD) age 47 (4.5), received 10.7 (2.6) HIRREM sessions over 11.3 (4.6) days (7.3 in office days). Data were collected before, and 22.6 (1.8) days after HIRREM completion. Use of HIRREM was associated with significantly increased HRV measured as rMSSD [from 25.3 (7.0) to 43.1 (13.0) ms, p=0.02]. BRS measured by high frequency alpha index improved [from 11.3 (8.0) to 20.1 (11.0) ms/mmHg, p=0.03]. All symptom inventories improved significantly (p<0.05), even with the small cohort. There were no adverse events or drop outs.

Conclusion: These pilot data provide the first report of significant autonomic cardiovascular benefits, and associated symptom improvements, with use of a closed-loop, allostatic therapy for a cohort of sworn law enforcement officers. Further studies are warranted to test the efficacy of this technology in a larger law enforcement cohort

Abstract P483: Healing a Broken Heart Using a Closed-loop, Allostatic, Neurotechnology: A Case Study in a Patient Suffering From Takotsubo Syndrome

Background: Stress cardiomyopathy or Takotsubo syndrome (TS) is an acute, reversible disorder of the heart characterized by left ventricular dysfunction, usually triggered by a stressful event. Excessive sympathetic excitation and shift in symapthovagal balance are proposed as mechanisms. High-resolution, relational, resonance-based, electroencephalic mirroring (HIRREM®) is a noninvasive, closed-loop, allostatic, neurotechnology using software algorithms to identify specific brain frequencies, translating them in real time into audible tones, to support self-optimization of brain rhythms and improve autonomic balance.

Objective: To evaluate benefits of HIRREM on autonomic function and symptom reduction in a 55 year old female enrolled in an IRB-approved open label feasibility study, after TS diagnosis.

Results: The participant received 13 HIRREM sessions over 11 days (9 in office days). Data were collected before, and 21 days after HIRREM completion. Baseline brain patterns had prominent right dominance at temporal lobes (sympathetic pattern), which balanced by the end of the sessions. Cardiovascular autonomic balance also shifted away from sympathetic towards parasympathetic. This was seen as reduced LF/HF ratio (from 1.89 to 0.63), increased heart rate variability (rMSSD from 27 to 40.8 ms), and baroreflex sensitivity (from 11.8 to 24.4 ms/mmHg). Blood pressure dropped from 132/90 to 121/88 with no change in heart rate despite discontinuation of her ACE inhibitor medication due to her BP being “too low.” HIRREM use was also associated with clinically meaningful improvements in multiple symptom inventories including insomnia (ISI) from 15 to 6, depression (CES-D) from 16 to 2, anxiety (GAD-7) from 18 to 2, and perceived stress scale (PSS) from 30 to 14. The patient reported resolution of a feeling of heaviness and discomfort in the chest after starting HIRREM sessions.

Conclusion: These data provide the first report of potential cardiovascular benefits of a non- pharmacological therapy to patients suffering from broken heart syndrome.

Abstract P123: Obesity and Alterations in Renal Function in Adolescents Born Preterm With Very Low Birth Weight

Background: Survival of children born preterm has improved dramatically, but prematurity and low birth weight may increase the risk of renal disease. Children born preterm have a lower glomerular filtration rate (GFR) and higher blood pressure (BP) compared to term peers, but compounding risk factors for renal disease among children born preterm remain poorly characterized. Indeed, patient factors such as obesity may influence the development of kidney disease. Thus, we hypothesize that obesity is associated with decreased renal function in adolescents born preterm with very low birth weight.

Methods: We measured systolic and diastolic BP, serum creatinine, and urine albumin at age 14 years in 124 adolescents born preterm with very low birth weight (mean birth weight 1056 g). We calculated the GFR by the Schwartz equation and the albumin-to-creatinine ratio (ACR) on morning urine samples. We used generalized linear models to estimate the association between obesity [body mass index (BMI) ≥95 th %ile for age and sex, n= 27] and renal function, adjusting for race, sex, maternal smoking during pregnancy, and birth weight z-score.

Results: Obesity was associated with higher systolic BP ( p =0.03). Compared to adolescents with BMI <95 th %ile, those with obesity had lower GFR ( β : -14.68 mL/min/1.73 m 2 , 95% CI -26.8 to -2.55). Adjustment for covariates attenuated this relationship ( β : -10.05 mL/min/1.73 m 2 , -21.12 to 1.03). Adolescents with obesity had a higher serum creatinine, but this did not reach statistical significance ( β : 0.05 mg/dL, -0.01 to 0.11). There was no difference in the ACR ( β : -0.05, -0.13 to 0.02).

Conclusions: Obese adolescents born preterm with very low birth weight exhibit higher systolic BP and lower GFR compared to those with BMI <95 th %ile, though the statistical significance of the relationship with GFR weakened after adjustment for possible confounders. Importantly, sex was a significant confounder that may influence the relationship between GFR and obesity, as female adolescents had significantly lower GFR than male adolescents. While obesity should be avoided, other factors should be considered that may contribute to worse renal function in adolescents born preterm with very low birth weight.

Abstract P204: Gender-specific Relationships Between Plasma Levels of Endocannabinoids and Vagal and Sympathetic Control of Heart Rate in Normotensive Obese Older Adults

Previous studies in obese individuals indicate higher circulating endocannabinoids anandamide (AEA) and 2-arachidonoylglycerol (2-AG) than in lean counterparts. However, the association between plasma endocannabinoids and autonomic control of blood pressure and heart rate has not been assessed in obesity. In a sample of normotensive, obese older adults we analyzed plasma content of the endocannabinoids AEA and total AG using mass spectrometry and examined correlations with various indices of spontaneous sympathovagal activity. Spontaneous baroreflex sensitivity (BRS) for heart rate control was calculated by spectral analysis of arterial pressure (AP) time (Sequence [Seq] Up, Seq Down and Seq All) and frequency (low-frequency [LF] and high-frequency [HF] α) domains from continuous resting AP recordings. In addition, time domain analysis was used to calculate heart rate variability (HRV) and blood pressure variability, indices of cardiac vagal tone and vascular sympathetic tone, respectively. The sample included 8 males and 17 females with a mean age of 68.4 ± 0.6 years, a mean body mass index of 35.0 ± 0.8 kg/m 2 , and mean AP of 101.0 ± 2.2 mmHg. Across the complete sample, we report a significant inverse correlation between plasma AG content and HFα, an index of the vagally-mediated parasympathetic spontaneous BRS ( r = -0.50, P < 0.05). We further report a significant inverse correlation between plasma AG and the vagal spontaneous BRS (Seq Up) in males ( r = -0.87, P < 0.01) but not in females. However, in females but not males we found significant positive relationships between AEA and LFα, an index of sympathetic spontaneous BRS ( r = 0.49, P < 0.05), and AEA and HRV ( r = 0.50, P < 0.05). These results are consistent with a role for the endocannabinoid system to modulate autonomic control of the circulation in populations at risk for hypertension and cardiovascular disease, and suggest gender differences that have yet to be elucidated.

Abstract 145: Central Angiotensin-(1-7) Treatment Attenuates ERK 1/2 Expression and Oxidative Stress in the Dorsal Medulla of Betamethasone-Exposed Sheep That Associates With Improved Blood Pressure and Baroreflex Sensitivity

Fetal exposure to betamethasone (BMX) that is routinely administered to women threatening premature delivery may lead to deleterious long-term effects on the central cardiovascular system. In the adult offspring of BMX-exposed sheep, we demonstrate increased mean arterial pressure (MAP) and attenuated baroreflex sensitivity (BRS). These responses are associated with dysregulation of the brain renin-angiotensin system (RAS) reflecting lower medullary expression of Angiotensin-(1-7) [Ang-(1-7)] and its beneficial actions. Moreover, mitogen activated protein kinase (MAPK), a key signaling cascade implicated in cardiovascular dysfunction and stimulation of oxidative stress is increased in the brain dorsomedial medulla (DMM). We hypothesize that loss of Ang-(1-7) tone with BMX is an underlying mechanism for the programming effects to increase MAPK and oxidative stress. Thus, we examined whether intracerebroventricular treatment with Ang-(1-7) that lowers MAP and improves BRS will impact MAPK signaling and downstream generation of reactive oxygen species (ROS). MAPK activation as detected by the ratio of phospho-ERK 1/2 to total ERK densities was significantly reduced by >80% in the Ang-(1-7)-treated BMX sheep as compared to the CSF-treated BMX controls (0.20 ± 0.07 vs 1.04 ± 0.31; p = 0.01, N=4/group). Ang-(1-7) treatment was associated with lower expression of two indices of ROS including 4-HNE (0.23 ± 0.03 vs. 0.31 ± 0.03 p = 0.03) and protein carbonyl content (9.95 ± 0.69 vs 15.94 ± 3.49; p = 0.07). Finally, regression analysis revealed that phospho-ERK 1/2 expression positively correlated with ROS (4-HNE) (r = 0.816; p = 0.01). The 4-HNE content also trended positively with MAP (r = 0.659, p = 0.08), but exhibited a negative correlation with BRS (r = -0.831; p = 0.01). We conclude that reduced central Ang-(1-7) tone may contribute to the chronic dysregulation of the MAPK and ROS signaling pathways within the DMM following BMX exposure. Moreover, Ang-(1-7) may constitute a potential therapeutic approach to improve autonomic dysfunction by attenuating both MAPK and ROS pathways. HD 047584.

Abstract P485: Use of a Noninvasive, Closed-loop, Allostatic, Neurotechnology Reduced Blood Pressure and Improved Heart Rate Variability in a Pre-hypertensive Cohort

Background: Prehypertension increases risk for hypertension and cardiovascular disease, but effective interventions have not been defined. Disturbed central control of cardiovascular regulation due to trauma, stress, anxiety or other causes can lead to prehypertension and impaired heart rate variability (HRV). High-resolution, relational, resonance-based, electroencephalic mirroring (HIRREM®) is a noninvasive, closed-loop, allostatic, acoustic stimulation neurotechnology using software algorithms to identify specific brain frequencies, and translate them in real time into audible tones, to support self-optimization of brain rhythms.

Objective: To evaluate the benefits of this nontraditional therapy on BP and autonomic function, subjects with untreated systolic BP of 120 to 139 or diastolic BP of 80 to 90 mmHg at baseline, who had enrolled in an IRB-approved open label feasibility study evaluating HIRREM for diverse neuropsychological disorders.

Results: 66 participants (40 female), mean (SD) age 43.3 (16.5), received 16 (5.7) HIRREM sessions over 22.4 (19.2) days, (9.5 (4.2) days with sessions). Data were collected before, and 14.4 (16.6) days after HIRREM completion. Use of HIRREM was associated with significantly reduced systolic (from 127.5 (8.0) to 122.9 (14.0) mmHg, p=0.011), and diastolic (from 82.0 (8.0) to 78.0 (9.0) mmHg, p= 0.014) arterial pressure, with no change in heart rate. HRV measured as SDNN increased (from 42.0 (17.0) to 50.0 (28.0) ms, p=0.002). Baroreflex sensitivity measured by sequence method improved (from 13.2 (8.0) to 17.2 (12.0) ms/mmHg, p=0.0001), with a trend for reduced sympathovagal tone measured by LF/HF ratio (from 2.5 (2.2) to 2.0 (1.8), p=0.068). There were no adverse events.

Conclusion: These data provide the first report of significant cardiovascular benefits of a closed-loop allostatic therapy for prehypertension. Blood pressure reduction and HRV improvement may prevent progression to more serious cardiovascular symptoms and diseases. Further studies are indicated to investigate the mechanism of the benefits associated with this promising intervention.

Abstract 051: Influence of Sex and Obesity on the Effect of Preterm Birth on the Renin-angiotensin System in Adolescents

Background: Preterm birth increases the risk of cardiovascular disease, but the underlying mechanisms are not known. Prematurity may induce programming effects that differentially influence the renin-angiotensin (Ang) system (RAS), particularly suppression of the beneficial Ang-(1-7) axis. Patient factors such as sex and obesity may influence the degree of RAS programming. Therefore, we hypothesize that preterm birth is associated with alterations in the RAS in adolescence in a sex and adiposity-dependent manner.

Methods: We evaluated a cohort of 175 adolescents born preterm and 51 term controls at age 14 years. We recorded systolic and diastolic BP z-scores, measured Ang II and Ang-(1-7) levels in plasma and urine, and calculated the peptide ratios. We applied generalized linear models to estimate the association between preterm birth and the RAS, adjusting for race, socioeconomic status, and maternal hypertension and smoking; the models were stratified by sex and overweight/obesity (body mass index ≥85 th %ile for age and sex).

Results: Mean systolic and diastolic BP z-scores were higher among those born preterm ( p <0.001 and p =0.03, respectively). Relative to term birth, preterm birth was associated with an increased plasma ratio of Ang II to Ang-(1-7) ( β : 4.42, 95% CI 1.52 to 7.32), decreased Ang II ( β : -5.16 pmol/L, -10.28 to -0.04), decreased Ang-(1-7) ( β : -5.38 pmol/L, -8.66 to -2.09), and a decreased urinary ratio of Ang II to Ang-(1-7) ( β : -0.13, -0.26 to -0.003). In stratified analyses, female sex ( β : -7.14 pmol/L, -11.03 to -3.24) and overweight/obesity ( β : -8.21 pmol/L, -12.51 to -3.91) were associated with greater reductions in plasma Ang-(1-7). Overweight/obesity was associated with a greater increase in the ratio of plasma Ang II to Ang-(1-7) ( β : +6.13, 0.58 to 11.68).

Conclusions: Circulating Ang-(1-7) was lower relative to Ang II in adolescents born preterm. This suggests fetal RAS programming may contribute to the increased risk of cardiovascular disease in those born preterm. We note an important influence of sex in that the decrease in Ang-(1-7) is intensified in girls. Moreover, obesity may confer a second physiologic insult through a higher Ang II/Ang-(1-7) that exacerbates the risk of cardiovascular disease, including hypertension.

Effects of supervised exercise and dietary nitrate in older adults with controlled hypertension and/or heart failure with preserved ejection fraction

Aerobic exercise training is an effective therapy to improve peak aerobic power (peak VO₂) in individuals with hypertension (HTN, AHA/ACC class A) and heart failure patients with preserved ejection fraction (HFpEF). High nitrate containing beetroot juice (BRJ) also improves sub-maximal endurance and decreases blood pressure in both HTN and HFpEF. We hypothesized that combining an aerobic exercise and dietary nitrate intervention would result in additive or even synergistic positive effects on exercise tolerance and blood pressure in HTN or HFpEF. We report results from two pilot studies examining the effects of supervised aerobic exercise combined with dietary nitrate in patients with controlled HTN (n = 26, average age 65 ± 5 years) and in patients with HFpEF (n = 20, average age 69 ± 7 years). All patients underwent an aerobic exercise training regimen; half were randomly assigned to consume a high nitrate-containing beet juice beverage (BRJ containing 6.1 mmol nitrate for the HFpEF study consumed three times a week and 8 mmol nitrate for the HTN study consumed daily) while the other half consumed a beet juice beverage with the nitrate removed (placebo). The main result was that there was no added benefit observed for any outcomes when comparing BRJ to placebo in either HTN or HFpEF patients undergoing exercise training (p ≥ 0.14). There were within-group benefits. In the pilot study in patients with HFpEF, aerobic endurance (primary outcome), defined as the exercise time to volitional exhaustion during submaximal cycling at 75% of maximal power output, improved during exercise training within each group from baseline to end of study, 369 ± 149 s vs 520 ± 257 s (p = 0.04) for the placebo group and 384 ± 129 s vs 483 ± 258 s for the BRJ group (p = 0.15). Resting systolic blood pressure in patients with HFpEF also improved during exercise training in both groups, 136 ± 16 mm Hg vs 122 ± 3 mm Hg for the placebo group (p < 0.05) and 132 ± 12 mm Hg vs 119 ± 9 mm Hg for the BRJ group (p < 0.05). In the HTN pilot study, during a treadmill graded exercise test, peak oxygen consumption (primary outcome) did not change significantly, but time to exhaustion (also a primary outcome) improved in both groups, 504 ± 32 s vs 601 ± 38 s (p < 0.05) for the placebo group and 690 ± 38 s vs 772 ± 95 s for the BRJ group (p < 0.05) which was associated with a reduction in supine resting systolic blood pressure in BRJ group. Arterial compliance also improved during aerobic exercise training in both the HFpEF and the HTN patients for both BRJ and placebo groups. Future work is needed to determine if larger nitrate doses would provide an added benefit to supervised aerobic exercise in HTN and HFpEF patients.