Low indoleamine 2, 3 dioxygenase (IDO) activity is associated with psycho-obstetric risk

OBJECTIVES

Preeclampsia and depression in pregnancy are among the most prevalent obstetric disorders with no known cures. While depression and preeclampsia each increase risk for the other, shared mechansisms are unclear. One possibility is low levels of Indoleamine 2,3 dioxygenase (IDO), which links immune dysregulation and oxidative arterial damage resulting in poor vascular function in both preeclampsia and depression. We hypothesized low circulating IDO activity levels in pregnancy would correspond to poor vascular function and depression symptoms.

STUDY DESIGN

In this nested case-control study, clinical, demographic, and biologic data from a cohort of pregnant women recruited to longitudinal studies measuring noninvasive vascular function and circulating factors were analyzed.

MAIN OUTCOME MEASURE

IDO activity across all three trimesters of pregnancy was measured using a colorimetric assay. Carotid-femoral pulse wave velocity (cfPWV), a measure of arterial stiffness, was also assessed throughout gestation by non-invasive applanation tonometry. Depression symptoms were assessed in pregnancy via the validated patient health questionnaire 9 (PHQ9).

RESULTS

Participants with low second and third trimester IDO activity had significantly decreased cfPWV. This association remained statistically significant when controlled for confounders such as BMI and chronic hypertension in the third but not second trimester. While PHQ9 scores were not associated with cfPWV differences, IDO activity was lower in moderate and severely depressed relative to non-depressed pregnant individuals.

CONCLUSION

These results implicate IDO in arterial stiffness and depression symptoms, suggesting that decreased IDO may be a central target for improved psycho-obstetric health.

Effect of acute heparin administration on glycocalyx thickness and endothelial function in healthy younger adults

The endothelial glycocalyx is a dynamic, gel-like layer that is critical to normal vascular endothelial function. Heparin impairs the endothelial glycocalyx and reduces vascular endothelial function in a murine model; however, this has yet to be tested in healthy humans. We hypothesized that a single bolus dose of heparin would increase circulating glycocalyx components and decrease endothelial glycocalyx thickness resulting in blunted brachial artery vasodilation in healthy younger adults. Healthy adults (n = 19, aged 18-39 yr, 53% female) underwent measurements of the endothelial glycocalyx and vascular endothelial function at baseline and after a single bolus 5,000 U dose of heparin. The glycocalyx components syndecan-1 and heparan sulfate were measured from plasma samples using enzyme-linked immunosorbent assays. Glycocalyx thickness was determined as perfused boundary region (PBR) in sublingual microvessels using the GlycoCheck. Endothelial function was measured via ultrasonography and quantified as brachial artery flow-mediated dilation (FMD). Following acute heparin administration, there was no increase in syndecan-1 or heparan sulfate (P = 0.90 and P = 0.49, respectively). In addition, there was no change in PBR 4-7 µm (P = 0.55), PBR 10-25 µm (P = 0.63), or 4-25 µm (P = 0.49) after heparin treatment. Furthermore, we did not observe a change in FMDmm (P = 0.23), FMD% (P = 0.35), or plasma nitrite concentrations (P = 0.10) in response to heparin. Finally, time to peak dilation and peak FMD normalized to shear stress were unchanged following heparin (P = 0.59 and P = 0.21, respectively). Our pilot study suggests that a single bolus intravenous dose of heparin does not result in endothelial glycocalyx degradation or vascular endothelial dysfunction in healthy younger adults.NEW & NOTEWORTHY The endothelial glycocalyx's role in modulating vascular endothelial dysfunction with aging and disease is becoming increasingly recognized. This study presents novel findings that acute heparin administration is not a feasible method to experimentally degrade the endothelial glycocalyx and measure concurrent changes in vascular endothelial function in healthy humans. Alternative approaches will be needed to translate findings from preclinical studies and test the effects of acute endothelial glycocalyx degradation on vascular endothelial function in humans.

Postpartum ambulatory and home blood pressure monitoring in women with history of preeclampsia: Diagnostic agreement and detection of masked hypertension

Women with a history of preeclampsia (hxPE) are at a four-fold higher risk for chronic hypertension after pregnancy compared with healthy pregnancy, but 'masked' hypertension cases are missed by clinical assessment alone. Twenty-four hour ambulatory blood pressure monitoring (ABPM) is the reference-standard for confirmation of hypertension diagnoses or detection of masked hypertension outside of clinical settings, whereas home blood pressure monitoring (HBPM) may represent a well-tolerated and practical alternative to ABPM in the postpartum period. The objectives of this study were to 1) assess concordance between ABPM and HBPM postpartum in women with a hxPE compared with healthy pregnancy controls and 2) evaluate HBPM in the detection of masked postpartum hypertension. Young women with a hxPE (N = 26) and controls (N = 36) underwent in-office, 24-h ABPM and 7-day HBPM 1-4 years postpartum. Chronic hypertension was more prevalent among women with a hxPE by all three blood pressure measures, but the prevalence of masked postpartum hypertension did not differ (36% vs 37%, P = 0.97). HBPM showed excellent agreement with ABPM (systolic: r = 0.78, intraclass coefficient [ICC] = 0.83; diastolic: r = 0.82, ICC = 0.88) and moderate concordance in classification of hypertension (κ = 0.54, P < 0.001). HBPM identified 21% of masked postpartum hypertension cases without false-positive cases, and HBPM measures among those with normotensive in-office readings could detect ABPM-defined masked hypertension (area under the curve [AUC] = 0.88 ± 0.06, P < 0.0001). The findings of the present study indicate that HBPM may be a useful screening modality prior or complementary to ABPM in the detection and management of postpartum hypertension.

Twenty-Four-Hour Blood Pressure Variability Is Associated With Lower Cognitive Performance in Young Women With a Recent History of Preeclampsia

BACKGROUND

Women with a history of preeclampsia (hxPE) exhibit sustained arterial stiffness and elevated blood pressure postpartum. Aortic stiffness and 24-hour blood pressure variability (BPV) are associated with age-related cognitive decline. Although hxPE is related to altered cognitive function, the association between aortic stiffness and BPV with cognitive performance in young women with hxPE has not been investigated. The objectives of this study were to (i) test whether cognitive performance is lower in young women with hxPE and (ii) determine whether aortic stiffness and BPV are associated with cognitive performance independent of 24-hour average blood pressure.

METHODS

Women with hxPE (N = 23) and healthy pregnancy controls (N = 38) were enrolled 1-3 years postpartum. Cognitive performance was assessed in domains of memory, processing speed, and executive function. Twenty-four-hour ambulatory blood pressure monitoring and carotid-femoral pulse wave velocity (cfPWV) were used to measure BPV and aortic stiffness, respectively.

RESULTS

Women with hxPE had slower processing speed (-0.56 ± 0.17 vs. 0.34 ± 0.11 Z-score, P < 0.001) and lower executive function (-0.43 ± 0.14 vs. 0.31 ± 0.10 Z-score, P = 0.004) compared with controls independent of education, whereas memory did not differ. BPV and cfPWV (adjusted for blood pressure) did not differ between women with hxPE and controls. Greater diastolic BPV was associated with lower executive function independent of 24-hour average blood pressure and education in women with hxPE (r = -0.48, P = 0.03) but not controls (r = 0.15, P = 0.38).

CONCLUSIONS

Select cognitive functions are reduced postpartum in young women with a recent hxPE and linked with elevated 24-hour diastolic BPV.

One-day acceptance and commitment therapy (ACT) workshop improves anxiety but not vascular function or inflammation in adults with moderate to high anxiety levels in a randomized controlled trial

OBJECTIVE

Acceptance and Commitment Therapy (ACT) is a behavioral intervention demonstrating sustained improvements in anxiety in individuals with chronic anxiety and psychological distress. Because anxiety disorders are associated with the development of cardiovascular disease (CVD), we hypothesized that a novel 1-day ACT workshop would both lower anxiety and improve vascular function in persons with moderate/high anxiety.

METHODS

In a randomized controlled study, 72 adults (age 33.9 ± 8.6 (SD) years) with baseline moderate/high anxiety completed a one-day ACT intervention (n = 44, age 33.9 ± 8.7 years) or control (n = 28, age 37.1 ± 10.1 years). Pre-specified secondary outcomes were measured over 12 weeks: aortic stiffness (carotid-femoral pulse wave velocity [cfPWV]), forearm vascular endothelial function (post-ischemic peak forearm blood flow [FBF] via plethysmography), and brachial artery flow-mediated dilation (FMD). Carotid artery stiffness (β-stiffness index), and inflammatory markers (C-reactive protein and tumor necrosis factor-alpha) were also explored.

RESULTS

Although the intervention had a significant and sustained effect on the primary outcome of anxiety as measured by the Beck Anxiety Inventory, the 1-day ACT workshop was not associated with improvement in vascular or inflammatory endpoints. The intervention was unexpectedly associated with increases in β-stiffness index that were also associated with changing trait anxiety.

CONCLUSION

Anxiety improvements did not translate into improvements in any of the vascular function outcomes. This may reflect a less-than-robust effect of the intervention on anxiety, failure in design to select those with vascular dysfunction, or not intervening on a relevant causal pathway. (Trial registration NCT02915874 at www.clinicaltrials.gov).

Abstract 30: Role For Adverse Childhood Experiences And Depression In Preeclampsia

Hypertensive diseases are associated with adverse experiences in childhood as well as depression. In order to determine if these associations were present in women with preeclampsia (PreE), a particularly devastating hypertensive disease in pregnancy, the scores from three questionnaires: Adverse Childhood Experiences (ACE), Edinburgh Postnatal Depression Scale (EPDS), and the Patient Health Questionnaire-9 (PHQ-9) were compared between women with PreE (n=32) and women without PreE (n=46) between 9 and 48 months postpartum (IRB# 201808705). ACE scores are calculated by summing an individual’s affirmative responses to specific adverse experiences during childhood. In our study, the average ACE score of individuals with PreE was higher than that of women without PreE (1.69 vs. 1.02, P=.04). We also divided women into groups based on whether their ACE score was ≤3 or ≥4 due to evidence that individuals who have experienced ≥4 ACEs are at greatest risk for physical and mental health conditions. Among our participants, 80% of women with an ACE score ≥4 (n=10) had PreE while only 35.3% of women with a score ≤3 (n=68) developed the condition (P=0.01). As well, the odds of having PreE were higher in those with ACE scores ≥4, compared with those with scores ≤3 (OR= 7.34; 95% CI = 1.44, 37.33). In a subset of participants, scores were available from EPDS, survey that identifies women who have postpartum depression 6 weeks after birth, and from the PHQ-9, another assessment for depression. Among our participants, the average EPDS score was higher in women with PreE than women without PreE (6.38, n=21 vs. 3.71, n=42 P=0.01), indicating more severe symptoms of postpartum depression in women who also had PreE. In addition, the average PHQ-9 score among women with PreE was higher than that of women without PreE (3.71, n=15 vs 1.86, n=37 P=.02) with a higher score indicating more severe depression. The average PHQ-9 score was also higher in women who had ACE scores ≥4 than women with scores ≤3 (4.00, n=4 vs. 2.27, n=48 P=.01) indicating that women with more adverse childhood events were more likely to experience depression. Together, these findings indicate that PreE may be associated with adverse events during childhood as well as depression in late pregnancy and/or postpartum.

Beat-to-Beat Blood Pressure Variability in the First Trimester Is Associated With the Development of Preeclampsia in a Prospective Cohort: Relation With Aortic Stiffness

Women with preeclampsia, a hypertensive disorder of pregnancy, exhibit greater beat-to-beat blood pressure variability (BPV) in the third trimester after clinical onset of the disorder. However, it remains unknown whether elevated BPV precedes the development of preeclampsia. A prospective study cohort of 139 women (age 30.2±4.0 years) were enrolled in early pregnancy (<14 weeks gestation). BPV was quantified by time domain analyses of 10-minute continuous beat-to-beat blood pressure recordings via finger photoplethysmography in the first, second, and third trimesters. Aortic stiffness (carotid-femoral pulse wave velocity) and spontaneous cardiovagal baroreflex sensitivity were also measured each trimester. Eighteen women (13%) developed preeclampsia. Systolic BPV was higher in all trimesters among women who developed versus did not develop preeclampsia (first: 4.8±1.3 versus 3.7±1.2, P=0.001; second: 5.1±1.8 versus 3.8±1.1, P=0.02; third: 5.2±0.8 versus 4.0±1.1 mm Hg, P=0.002). Elevated first trimester systolic BPV was associated with preeclampsia (odds ratio, 1.94 [95% CI, 1.27-2.99]), even after adjusting for risk factors (age, body mass index, systolic blood pressure, history of preeclampsia, and diabetes mellitus) and was a significant predictor of preeclampsia (area under the receiver operator characteristic curve=0.75±0.07; P=0.002). Carotid-femoral pulse wave velocity was elevated in the first trimester among women who developed preeclampsia (5.9±0.8 versus 5.2±0.8 m/s; P=0.002) and was associated with BPV after adjustment for mean blood pressure (r=0.26; P=0.005). First trimester baroreflex sensitivity did not differ between groups (P=0.23) and was not related to BPV (P=0.36). Elevated systolic BPV is independently associated with the development of preeclampsia as early as the first trimester, possibly mediated in part by higher aortic stiffness.

Elevated Muscle Sympathetic Nerve Activity Contributes to Central Artery Stiffness in Young and Middle-Age/Older Adults

Muscle sympathetic nerve activity (MSNA) influences the mechanical properties (ie, vascular smooth muscle tone and stiffness) of peripheral arteries, but it remains controversial whether MSNA contributes to stiffness of central arteries, such as the aorta and carotids. We examined whether elevated MSNA (age-related) would be independently associated with greater stiffness of central (carotid-femoral pulse wave velocity [PWV]) and peripheral (carotid-brachial PWV) arteries, in addition to lower carotid compliance coefficient, in healthy men and women (n=88, age: 19-73 years, 52% men). We also examined whether acute elevations in MSNA without increases in mean arterial pressure using graded levels of lower body negative pressure would augment central and peripheral artery stiffness in young (n=15, 60% men) and middle-age/older (MA/O, n=14, 43% men) adults. Resting MSNA burst frequency (bursts·min^-1) was significantly correlated with carotid-femoral PWV ( R=0.44, P<0.001), carotid-brachial PWV ( R=0.32, P=0.004), and carotid compliance coefficient ( R=0.28, P=0.01) after controlling for sex, mean arterial pressure, heart rate, and waist-to-hip ratio (central obesity), but these correlations were abolished after further controlling for age (all P>0.05). In young and MA/O adults, MSNA was elevated during lower body negative pressure ( P<0.001) and produced significant increases in carotid-femoral PWV (young: Δ+1.3±0.3 versus MA/O: Δ+1.0±0.3 m·s^-1, P=0.53) and carotid-brachial PWV (young: Δ+0.7±0.3 versus MA/O: Δ+0.7±0.5 m·s^-1, P=0.92), whereas carotid compliance coefficient during lower body negative pressure was significantly reduced in young but not MA/O (young: Δ-0.04±0.01 versus MA/O: Δ0.001±0.008 mm²·mm Hg^-1, P<0.01). Collectively, these data demonstrate the influence of MSNA on central artery stiffness and its potential contribution to age-related increases in stiffness of both peripheral and central arteries.

Abstract 149: Postpartum Cognitive Function in Young Women With a History of Preeclampsia: Association With Blood Pressure but Not Large Artery Stiffness

Introduction: Women with a history of preeclampsia (PE) have elevated large artery stiffness and blood pressure (BP) several years postpartum. Age-related increases in aortic stiffness are deleterious to brain structure and cognitive function; however, the relationship between large artery stiffness and cognitive function has not been assessed in women with a history of PE. The purpose of this study was to determine the extent to which large artery stiffness and BP are associated with cognitive function in women with a history of PE.

Methods: Women with a history of PE (n=12; age 33±1 yrs; BMI 28.5±3.1 kg/m 2 ) and healthy pregnancy controls (n=7; age 34±2 yrs; BMI 26.5±4.0 kg/m 2 ) were assessed one year postpartum. Brachial BP was collected in triplicate using an automated cuff. Aortic stiffness was measured via applanation tonometry and quantified as carotid-femoral pulse wave velocity (cfPWV). Carotid stiffness (β-stiffness) was obtained via ultrasonography and carotid tonometry. Cognitive function was assessed in domains of memory, processing speed, and executive function.

Results: Women with a history of PE had higher systolic BP (121±4 vs. 104±3 mmHg, p<0.01) and cfPWV (6.2±0.4 vs. 5.1±0.2 m/s, p=0.06), though the latter did not reach statistical significance. There was no difference between groups in β-stiffness (6.1±0.4 vs. 6.1±0.6 U, p=0.97). Cognitive domains of executive function, memory, and processing speed did not differ between groups (all p>0.05). Systolic BP was associated with reductions in executive function (r = -0.52, p=0.04) independent of education level, but was not related to reductions in memory or processing speed. Arterial stiffness was not associated with cognition.

Conclusions: Women with a history of PE had elevated systolic BP and aortic stiffness, but only BP was associated with reductions in executive function. These preliminary findings suggest that young women with a history of PE may be vulnerable to reductions in cognitive function related to persistent elevated systolic BP.

Abstract 030: Low Indoleamine 2,3 Dioxygenase Activity in Pregnancy are Associated With Increased Carotid-Femoral Pulse Wave Velocity in Preeclampsia

Preeclampsia is a prevalent multi-organ complication of pregnancy that is characterized by gestational hypertension and proteinuria. Immunologic and vascular alterations clearly occur before clinical disease. One mechanism that could explain both the exaggerated immune response and vascular dysfunction involves indoleamine 2, 3 dioxygenase (IDO). We have previously shown that the IDO-KO mouse replicates the vascular and obstetric phenotypes of human preeclampsia. We hypothesize that decreases in IDO activity are associated with vascular dysfunction as measured by carotid-femoral pulse wave velocity (PWV), a measure of aortic stiffness. We test this hypothesis in this nested case control study of two similarly recruited prospective cohorts (Preeclampsia IDO Vascular Function and Perinatal Outcomes study IRB: 201009701), and the (Early Vascular Dysfunction and Elevated Copeptin in Human Preeclampsia study IRB: 201503789). A total of 136 control and 13 preeclamptic pregnant women were recruited to measure vascular function and immunovascular factors throughout gestation. Plasma IDO activity was colorimetrically measured and trimester specific quartiles for IDO activity were calculated. PWV was measured via tonometry. Highest and lowest IDO activity quartile groups were compared. First trimester IDO activity was not associated with differences in PWV throughout gestation. Lower second and third trimester IDO activity was associated with higher PWV throughout gestation (1 st trimester: 6.8 ± 0.3 vs 5.5 ± 0.2, P<0.001; 2 nd trimester: 7.1 ± 0.4 vs 5.1 ± 0.2 P<0.001; 3 rd trimester 6.5 ± 0.2 vs 5.9 ± 0.2 m/s, P<0.001). Even after controlling for preeclampsia, third trimester IDO activity was inversely associated with PWV (Beta IDO=-11, p=0.023 and Beta preeclampsia=0.150, p=0.753). Consistent with our hypothesis, our data demonstrate IDO activity is inversely associated with vascular dysfunction. Future studies will elucidate the molecular immunovascular mechanisms underlying this association in preeclampsia.

Abstract 109: Association Between Aortic Stiffness and Lower Retinal Microvascular Blood Flow Revealed by Laser Speckle Flowgraphy: Surrogate Measures of Cerebral Microcirculation in Humans

The age-related increase in aortic stiffness increases systolic blood pressure (BP) and flow pulsatility and is associated with target organ damage such as ischemic cerebrovascular disease. However, the mechanistic link between aortic stiffness and cerebrovascular disease remains unclear because techniques available to non-invasively assess dynamic changes in the human brain microcirculation with high spatial and temporal resolution are limited. Given the evidence that disease- and age- related alterations in the retinal microvasculature may mirror changes in the cerebral microvasculature, we assessed resting and dynamic changes in the retinal microcirculation using high resolution laser speckle flowgraphy. We tested the hypothesis that retinal microvascular blood flow at rest and during acute increases in BP would be associated with age-related increases in aortic stiffness (carotid-femoral pulse wave velocity, CFPWV). In 40 healthy subjects (35 ± 2 years; 25-60 years; 18 M/22 F; systolic BP: 123 ± 2 mmHg; diastolic BP: 77 ± 2 mmHg), retinal arterial blood flow was assessed at baseline (following dilation of the left pupil with 0.5% topicamide), and during a sympatho-excitatory stimulus (2-min cold pressor test). At baseline, lower retinal blood flow was significantly correlated with higher CFPWV (R=-0.35, P=0.03) and older age (R=-0.38, P=0.02) independent of mean BP (partial correlation). In response to the CPT, significant increases were observed in mean BP (BL: 92 ± 2 vs. CPT: 106 ± 2 mmHg, P<0.001) and retinal blood flow (BL: 215 ± 6 vs. CPT: 230 ± 8 AU, P<0.001). The relation between higher CFPWV and lower retinal blood flow observed at baseline was maintained during the CPT independent of mean BP (R=-0.37, P=0.03). However, no association was noted between CFPWV and % change in retinal blood flow. These preliminary data suggest that higher aortic stiffness is associated with lower retinal microvascular blood flow at rest and during sympatho-excitation independent of BP. These findings have important implications for age-related ocular degeneration, and lend support for future studies aiming to identify retinal microvascular abnormalities as markers of age-related cerebrovascular pathology.

Relative burst amplitude of muscle sympathetic nerve activity is an indicator of altered sympathetic outflow in chronic anxiety

Relative burst amplitude of muscle sympathetic nerve activity (MSNA) is an indicator of augmented sympathetic outflow and contributes to greater vasoconstrictor responses. Evidence suggests anxiety-induced augmentation of relative MSNA burst amplitude in patients with panic disorder; thus we hypothesized that acute stress would result in augmented relative MSNA burst amplitude and vasoconstriction in individuals with chronic anxiety. Eighteen participants with chronic anxiety (ANX; 8 men, 10 women, 32 ± 2 yr) and 18 healthy control subjects with low or no anxiety (CON; 8 men, 10 women, 39 ± 3 yr) were studied. Baseline MSNA and 24-h blood pressure were similar between ANX and CON ( P > 0.05); however, nocturnal systolic blood pressure % dipping was blunted among ANX ( P = 0.02). Relative MSNA burst amplitude was significantly greater among ANX compared with CON immediately preceding (anticipation) and during physiological stress [2-min cold pressor test; ANX: 73 ± 5 vs. CON: 59 ± 3% arbitrary units (AU), P = 0.03] and mental stress (4-min mental arithmetic; ANX: 65 ± 3 vs. CON: 54 ± 3% AU, P = 0.02). Increases in MSNA burst frequency, incidence, and total activity in response to stress were not augmented among ANX compared with CON ( P > 0.05), and reduction in brachial artery conductance during cold stress was similar between ANX and CON ( P = 0.92). Relative MSNA burst amplitude during mental stress was strongly correlated with state ( P < 0.01) and trait ( P = 0.01) anxiety (State-Trait Anxiety Inventory), independent of age, sex, and body mass index. Thus in response to acute stress, both mental and physiological, individuals with chronic anxiety demonstrate selective augmentation in relative MSNA burst amplitude, indicating enhanced sympathetic drive in a population with higher risk for cardiovascular disease. NEW & NOTEWORTHY Relative burst amplitude of muscle sympathetic nerve activity in response to acute mental and physiological stress is selectively augmented in individuals with chronic anxiety, which is a prevalent condition that is associated with the development of cardiovascular disease. Augmented sympathetic burst amplitude occurs with chronic anxiety in the absence of common comorbidities. These findings provide important insight into the relation between anxiety, acute stress and sympathetic activation.

Abstract P270: First Trimester Elevation in Circulating Endothelin-1 and Arterial Stiffness are Predictive of Late Pregnancy Preeclampsia

Preeclampsia (PE) is characterized by late pregnancy hypertension and proteinuria. PE causes significant morbidity for the maternal-fetal unit. Circulating endothelin-1 (ET-1), a potent vasoconstrictor, is elevated at the time of diagnosis of human PE. In addition, women with PE demonstrate arterial stiffness as early as the end of the first trimester. However, it is unknown if arterial stiffness is associated with a first trimester elevation in ET-1 and post-delivery placental ET-1. We hypothesized that 1) first trimester plasma ET-1 is elevated and is associated with arterial stiffness in women who develop PE; 2) first trimester ET-1 is predictive of PE; and 3) placental ET-1 is increased in PE. To address these questions, we performed a nested case-control study in women at risk for PE. First trimester plasma ET-1 was measured via ELISA; aortic stiffness and carotid beta-stiffness (CβS) were measured by carotid-femoral pulse-wave velocity (CFPWV) and carotid tonometry/ultrasound, respectively. While the maternal age of controls (n=126; age 30 ± 0.45 years) and PE (n=15; age 31 ± 1.3 years) were similar, the PE group had a higher first trimester BMI (35 ± 3 vs. 29 ± 1 kg/m 2 , p = 0.01), systolic (125 ± 2 vs. 113 ± 1 mmHg, p< 0.01) and diastolic blood pressure (68 ± 2 vs. 60 ± 1 mmHg, p< 0.01) compared with controls. In addition, first trimester plasma ET-1 (2.7 ± 0.4 vs. 2.0 ± 0.2 pg/mL, p < 0.01), CFPWV (7.2 ± 0.5 vs. 6.1 ± 0.2 m/s, p = 0.016), and CβS (8.4 ± 1.9 vs. 6.3 ± 0.3, p = 0.055) were higher in the PE group. Consistent with previous studies, third trimester plasma ET-1 was elevated in the PE group (2.9 ± 1.1 vs. 1.6 ± 0.1 pg/mL, p < 0.01) which paralleled a 2.5 fold increase in placental decidual ET-1 mRNA (p < 0.0001). ROC analyses showed that first trimester plasma ET-1 (AUC=0.71, p < 0.001) and CFPWV (AUC=0.70, p=0.014) were predictive of PE. This study supports the novel concept that elevated ET-1 in preeclampsia begins early in the first trimester and is associated with premature arterial stiffness. Further, these novel data suggest that ET-1 may play an important role in the first trimester prediction and pathogenesis of preeclampsia.

Abstract P105: Greater 24 Hour Blood Pressure Variability is Associated With Higher 24 Hour Systolic Blood Pressure and Glucose Independent of Age and Large Elastic Artery Stiffness in Normotensive Adults

Older age is associated with elevated large elastic artery stiffness, a strong predictor of cardiovascular (CVD) risk in middle-age/older (MA/O) adults independent of blood pressure (BP). Greater 24-hour systolic BP variability (BPV) is also an independent risk factor for CVD and is linked to large artery stiffness in MA/O adults with hypertension and diabetes. However, its relation to age-related arterial stiffness in adults with low risk factor burden is unclear. We hypothesized that higher systolic BPV would be: 1) associated with advancing age, and 2) related to elevated aortic and carotid artery stiffness among healthy MA/O adults. To determine this, 98 healthy adults (ages 19-70 yrs) with measurements of systolic BPV (standard deviation of 24 hr systolic BP) via ambulatory BP monitoring, aortic stiffness (carotid-femoral pulse wave velocity, cfPWV), carotid artery stiffness (β-stiffness via carotid tonometry/B mode ultrasound) and circulating metabolic factors were included. In the entire cohort, greater systolic BPV was not associated with age, cfPWV, carotid β stiffness or circulating lipids/glucose (all P>0.05), but was correlated (age-adjusted) with 24 hr systolic BP (r= 0.41, P<0.001) and BMI (r= 0.21, P<0.05). In stepwise linear regression analyses that included age, sex, BMI, only 24 hr systolic BP was associated with systolic BPV (β= 0.14 ± 0.03, Model R 2 = 0.20, P< 0.001). Interestingly, there was no difference in 24 hr systolic BPV (11.4 ± 0.4 vs 11.4 ± 0.5 SD mmHg, P=0.99) in young (n=55; 29.0 ± 0.7 yrs) vs. MA/O (n= 43; 53.0 ± 1.2 yrs) adults despite higher cfPWV (594 ± 12 vs 913 ± 39 cm/sec, P<0.001), carotid β-stiffness (6.8 ± 0.6 vs 9.3 ±0.9 U, P=0.001) and 24 hr systolic BP (121 ± 1 vs 125 ± 2 mmHg, P<0.05). Systolic BPV was associated with BMI (r= 0.42, p< 0.01) and fasting blood glucose (r= 0.54, P= 0.001) in MA/O but not young adults. In a stepwise linear regression model among MA/O, 24 hr systolic BP (β= 0.18 ± 0.04, R 2 = 0.36, P<0.001) and fasting glucose (β= 0.10 ± 0.05, R 2 change= 0.07, P<0.001) were the only significant correlates of systolic BPV (Model R 2 = 0.43, P<0.001). In conclusion, 24 hr systolic BP and fasting blood glucose, but not age or large elastic artery stiffness, were the strongest determinants of higher systolic BPV in normotensive MA/O adults.