1
|
Hissen SL, Takeda R, Badrov MB, Arias-Franklin S, Patel S, Nelson DB, Babb TG, Fu Q. Impact of maternal obesity on resting muscle sympathetic nerve activity during uncomplicated pregnancy: a longitudinal assessment. Am J Physiol Regul Integr Comp Physiol 2024; 326:R10-R18. [PMID: 37955129 PMCID: PMC11283889 DOI: 10.1152/ajpregu.00098.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 10/12/2023] [Accepted: 10/30/2023] [Indexed: 11/14/2023]
Abstract
Maternal obesity increases the risk of adverse pregnancy outcomes. The mechanisms that contribute to this elevated risk are unclear but may be related to greater activity of the sympathetic nervous system, which is associated with hypertensive disorders of pregnancy. We hypothesized that resting muscle sympathetic nerve activity (MSNA) would be greater in women with obesity during pregnancy when compared with normal-weight women. Blood pressure, heart rate, and MSNA were recorded during 5 min of supine rest in 14 normal-weight women [body mass index (BMI) 22.1 ± 2.1 (SD) kg/m2] and 14 women with obesity (BMI 33.9 ± 3.5 kg/m2) during (early and late) pregnancy and postpartum. All women had uncomplicated pregnancies. Resting MSNA burst frequency was not different between groups during early (normal weight 17 ± 10 vs. obesity 22 ± 15 bursts/min, P = 0.35) but was significantly greater in the obesity group during late pregnancy (23 ± 13 vs. 35 ± 15 bursts/min, P = 0.031) and not different postpartum (10 ± 6 vs. 9 ± 7 bursts/min, P = 0.74). These findings were also apparent when comparing burst incidence and total activity. Although still within the normotensive range, systolic blood pressure was greater in the obesity group across all time points (P = 0.002). Diastolic blood pressure was lower during pregnancy compared with postpartum (P < 0.001) and not different between groups (P = 0.488). Heart rate increased throughout pregnancy in both groups (P < 0.001). Our findings suggest that maternal obesity is associated with greater increases in sympathetic activity even during uncomplicated pregnancy. Future research is needed to determine if this is linked with an increased risk of adverse outcomes or is required to maintain homeostasis in pregnancy.NEW & NOTEWORTHY The impact of maternal obesity on resting muscle sympathetic nerve activity was examined during (early and late) and after uncomplicated pregnancy. Resting muscle sympathetic nerve activity is not different during early pregnancy or postpartum but is significantly elevated in women with obesity during late pregnancy when compared with normal-weight women. Future research is needed to determine if this is linked with an increased risk of adverse outcomes or is required to maintain homeostasis in pregnancy.
Collapse
Affiliation(s)
- Sarah L Hissen
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, United States
- The University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Ryosuke Takeda
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, United States
- The University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Mark B Badrov
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, United States
- The University of Texas Southwestern Medical Center, Dallas, Texas, United States
- University Health Network, Toronto, Ontario, Canada
| | - Sonia Arias-Franklin
- The University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Shivani Patel
- The University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - David B Nelson
- The University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Tony G Babb
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, United States
- The University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Qi Fu
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, United States
- The University of Texas Southwestern Medical Center, Dallas, Texas, United States
| |
Collapse
|
2
|
Brislane Á, Davenport MH, Steinback CD. The sympathetic nervous system in healthy and hypertensive pregnancies: physiology or pathology? Exp Physiol 2023; 108:1238-1244. [PMID: 36459575 PMCID: PMC10988427 DOI: 10.1113/ep089665] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 10/18/2022] [Indexed: 09/30/2023]
Abstract
NEW FINDINGS What is the topic of this review? Sympathoexcitation in both healthy and hypertensive pregnancies, and concurrent adaptations along the neurovascular cascade. What advances does it highlight? Known and plausible adaptations along the neurovascular cascade which may offset elevated MSNA in normotensive pregnancy while also highlighting knowledge gaps regarding understudied pathways. ABSTRACT The progression from conception through to the postpartum period represents an extraordinary period of physiological adaptation in the mother to support the growth and development of the fetus. Healthy, normotensive human pregnancies are associated with striking increases in both plasma volume and sympathetic nerve activity, yet normal or reduced blood pressure; it represents a unique period of apparent healthy sympathetic hyperactivity. However, how this normal blood pressure is achieved in the face of sympathoexcitation, and the mechanisms responsible for this increased activity are unclear. Importantly, sympathetic activation has been implicated in hypertensive pregnancy disorders - the leading causes of maternal-fetal morbidity and mortality in the developed world. An understudied link between pregnancy and the development of maternal hypertension may lie in the sympathetic nervous system regulation of blood pressure. This brief review presents the latest data on sympathoexcitation in both healthy and hypertensive pregnancies, and concurrent adaptations along the neurovascular cascade.
Collapse
Affiliation(s)
- Áine Brislane
- Program for Pregnancy & Postpartum HealthNeurovascular Health Lab, Faculty of Kinesiology, Sport, and RecreationWomen and Children's Health Research InstituteAlberta Diabetes InstituteUniversity of AlbertaAlbertaCanada
| | - Margie H. Davenport
- Program for Pregnancy & Postpartum HealthNeurovascular Health Lab, Faculty of Kinesiology, Sport, and RecreationWomen and Children's Health Research InstituteAlberta Diabetes InstituteUniversity of AlbertaAlbertaCanada
| | - Craig D. Steinback
- Program for Pregnancy & Postpartum HealthNeurovascular Health Lab, Faculty of Kinesiology, Sport, and RecreationWomen and Children's Health Research InstituteAlberta Diabetes InstituteUniversity of AlbertaAlbertaCanada
| |
Collapse
|
3
|
Greenwall KM, Brislane Á, Matenchuk BA, Sivak A, Davenport MH, Steinback CD. Muscle sympathetic nerve activity during pregnancy: A systematic review and meta-analysis. Physiol Rep 2023; 11:e15626. [PMID: 36905144 PMCID: PMC10006587 DOI: 10.14814/phy2.15626] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 02/06/2023] [Accepted: 02/09/2023] [Indexed: 03/12/2023] Open
Abstract
We conducted a systematic review and meta-analysis to quantify the impact of healthy and complex pregnancy on muscle sympathetic nerve activity (MSNA) at rest, and in response to stress. Structured searches of electronic databases were performed until February 23, 2022. All study designs (except reviews) were included: population (pregnant individuals); exposures (healthy and complicated pregnancy with direct measures of MSNA); comparator (individuals who were not pregnant, or with uncomplicated pregnancy); and outcomes (MSNA, BP, and heart rate). Twenty-seven studies (N = 807) were included. MSNA burst frequency was higher in pregnancy (n = 201) versus non-pregnant controls (n = 194) (Mean Differences [MD], MD: 10.6 bursts/min; 95% CI: 7.2, 14.0; I2 = 72%). Accounting for the normative increase in heart rate with gestation, burst incidence was also higher during pregnancy (Pregnant N = 189, non-pregnant N = 173; MD: 11 bpm; 95% CI: 8, 13 bpm; I2 = 47%; p < 0.0001). Meta-regression analyses confirmed that although sympathetic burst frequency and incidence are augmented during pregnancy, this was not significantly associated with gestational age. Compared to uncomplicated pregnancy, individuals with obesity, obstructive sleep apnea, and gestational hypertension exhibited sympathetic hyperactivity, while individuals with gestational diabetes mellitus or preeclampsia did not. Uncomplicated pregnancies exhibited a lesser response to head-up tilt, but an exaggerated sympathetic responsiveness to cold pressor stress compared to non-pregnant individuals. MSNA is higher in pregnant individuals and further increased with some, but not all pregnancy complications. PROSPERO registration number: CRD42022311590.
Collapse
Affiliation(s)
- Kelly M. Greenwall
- Program for Pregnancy and Postpartum Health, Physical Activity and Diabetes Laboratory, Faculty of Physical Education and Recreation, the Women and Children's Health Research Institute, and the Alberta Diabetes InstituteUniversity of Alberta, and the University of Alberta LibrariesEdmontonAlbertaCanada
| | - Áine Brislane
- Program for Pregnancy and Postpartum Health, Physical Activity and Diabetes Laboratory, Faculty of Physical Education and Recreation, the Women and Children's Health Research Institute, and the Alberta Diabetes InstituteUniversity of Alberta, and the University of Alberta LibrariesEdmontonAlbertaCanada
| | - Brittany A. Matenchuk
- Program for Pregnancy and Postpartum Health, Physical Activity and Diabetes Laboratory, Faculty of Physical Education and Recreation, the Women and Children's Health Research Institute, and the Alberta Diabetes InstituteUniversity of Alberta, and the University of Alberta LibrariesEdmontonAlbertaCanada
| | - Allison Sivak
- Program for Pregnancy and Postpartum Health, Physical Activity and Diabetes Laboratory, Faculty of Physical Education and Recreation, the Women and Children's Health Research Institute, and the Alberta Diabetes InstituteUniversity of Alberta, and the University of Alberta LibrariesEdmontonAlbertaCanada
| | - Margie H. Davenport
- Program for Pregnancy and Postpartum Health, Physical Activity and Diabetes Laboratory, Faculty of Physical Education and Recreation, the Women and Children's Health Research Institute, and the Alberta Diabetes InstituteUniversity of Alberta, and the University of Alberta LibrariesEdmontonAlbertaCanada
| | - Craig D. Steinback
- Program for Pregnancy and Postpartum Health, Physical Activity and Diabetes Laboratory, Faculty of Physical Education and Recreation, the Women and Children's Health Research Institute, and the Alberta Diabetes InstituteUniversity of Alberta, and the University of Alberta LibrariesEdmontonAlbertaCanada
| |
Collapse
|
4
|
Issotina Zibrila A, Wang Z, Sangaré-Oumar MM, Zeng M, Liu X, Wang X, Zeng Z, Kang YM, Liu J. Role of blood-borne factors in sympathoexcitation-mediated hypertension: Potential neurally mediated hypertension in preeclampsia. Life Sci 2022; 320:121351. [PMID: 36592790 DOI: 10.1016/j.lfs.2022.121351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 12/19/2022] [Accepted: 12/27/2022] [Indexed: 01/01/2023]
Abstract
Hypertension remains a threat for society due to its unknown causes, preventing proper management, for the growing number of patients, for its state as a high-risk factor for stroke, cardiac and renal complication and as cause of disability. Data from clinical and animal researches have suggested the important role of many soluble factors in the pathophysiology of hypertension through their neuro-stimulating effects. Central targets of these factors are of molecular, cellular and structural nature. Preeclampsia (PE) is characterized by high level of soluble factors with strong pro-hypertensive activity and includes immune factors such as proinflammatory cytokines (PICs). The potential neural effect of those factors in PE is still poorly understood. Shedding light into the potential central effect of the soluble factors in PE may advance our current comprehension of the pathophysiology of hypertension in PE, which will contribute to better management of the disease. In this paper, we summarized existing data in respect of hypothesis of this review, that is, the existence of the neural component in the pathophysiology of the hypertension in PE. Future studies would address this hypothesis to broaden our understanding of the pathophysiology of hypertension in PE.
Collapse
Affiliation(s)
- Abdoulaye Issotina Zibrila
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University School of Basic Medical Sciences, Key Laboratory of Environment and Genes Related to Diseases, Xi'an 710061, Shaanxi, PR China; Department of Animal Physiology, Faculty of science and Technology, University of Abomey-Calavi, 06 BP 2584 Cotonou, Benin
| | - Zheng Wang
- Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, PR China
| | - Machioud Maxime Sangaré-Oumar
- Department of Animal Physiology, Faculty of science and Technology, University of Abomey-Calavi, 06 BP 2584 Cotonou, Benin
| | - Ming Zeng
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University School of Basic Medical Sciences, Key Laboratory of Environment and Genes Related to Diseases, Xi'an 710061, Shaanxi, PR China
| | - Xiaoxu Liu
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University School of Basic Medical Sciences, Key Laboratory of Environment and Genes Related to Diseases, Xi'an 710061, Shaanxi, PR China
| | - Xiaomin Wang
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University School of Basic Medical Sciences, Key Laboratory of Environment and Genes Related to Diseases, Xi'an 710061, Shaanxi, PR China
| | - Zhaoshu Zeng
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University School of Basic Medical Sciences, Key Laboratory of Environment and Genes Related to Diseases, Xi'an 710061, Shaanxi, PR China
| | - Yu-Ming Kang
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University School of Basic Medical Sciences, Key Laboratory of Environment and Genes Related to Diseases, Xi'an 710061, Shaanxi, PR China.
| | - Jinjun Liu
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University School of Basic Medical Sciences, Key Laboratory of Environment and Genes Related to Diseases, Xi'an 710061, Shaanxi, PR China.
| |
Collapse
|
5
|
Hissen SL, Takeda R, Yoo JK, Badrov MB, Stickford ASL, Best SA, Okada Y, Jarvis SS, Nelson DB, Fu Q. Posture-related changes in sympathetic baroreflex sensitivity during normal pregnancy. Clin Auton Res 2022; 32:485-495. [PMID: 36394777 PMCID: PMC11440427 DOI: 10.1007/s10286-022-00903-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 10/12/2022] [Indexed: 11/18/2022]
Abstract
Normal pregnancy is associated with vast adjustments in cardiovascular autonomic control. Sympathetic baroreflex sensitivity has been reported to be attenuated during pregnancy in animal models, but most studies in humans are cross-sectional and findings from longitudinal case studies are inconclusive. It remains unclear how sympathetic baroreflex sensitivity is altered longitudinally during pregnancy within an individual in different body postures. Therefore, this study examined the impact of posture on sympathetic baroreflex sensitivity in 24 normal-weight normotensive pregnant women. Spontaneous sympathetic baroreflex sensitivity was assessed during early (6-11 weeks) and late (32-36 weeks) pregnancy and 6-10 weeks postpartum in the supine posture and graded head-up tilt (30° and 60°). In addition, data from the postpartum period were compared with (and no different to) 18 age-matched non-pregnant women to confirm that the postpartum period was reflective of a non-pregnant condition (online supplement). When compared with postpartum (-3.8 ± 0.4 bursts/100 heartbeats/mmHg), supine sympathetic baroreflex sensitivity was augmented during early pregnancy (-5.9 ± 0.4 bursts/100 heartbeats/mmHg, P < 0.001). However, sympathetic baroreflex sensitivity at 30° or 60° head-up tilt was not different between any phase of gestation (P > 0.05). When compared to supine, sympathetic baroreflex sensitivity at 60° head-up tilt was significantly blunted during early (Δ2.0 ± 0.7 bursts/100 heartbeats/mmHg, P = 0.024) and late (Δ1.5 ± 0.6 bursts/100 heartbeats/mmHg, P = 0.049) pregnancy but did not change postpartum (Δ0.4 ± 0.6 bursts/100 heartbeats/mmHg, P = 1.0). These data show that time-course changes in sympathetic baroreflex sensitivity are dependent on the posture it is examined in and provides a foundation of normal blood pressure regulation during pregnancy for future studies in women at risk for adverse pregnancy outcomes.
Collapse
Affiliation(s)
- Sarah L Hissen
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, 7232 Greenville Avenue, Dallas, TX, 75231, USA
- The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Ryosuke Takeda
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, 7232 Greenville Avenue, Dallas, TX, 75231, USA
- The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Jeung-Ki Yoo
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, 7232 Greenville Avenue, Dallas, TX, 75231, USA
- The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Mark B Badrov
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, 7232 Greenville Avenue, Dallas, TX, 75231, USA
- University Health Network, Toronto, ON, Canada
| | - Abigail S L Stickford
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, 7232 Greenville Avenue, Dallas, TX, 75231, USA
- Medtronic Plc, Minneapolis, MN, USA
| | - Stuart A Best
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, 7232 Greenville Avenue, Dallas, TX, 75231, USA
- University of Kentucky, Lexington, KY, USA
| | - Yoshiyuki Okada
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, 7232 Greenville Avenue, Dallas, TX, 75231, USA
- Hiroshima University, Hiroshima, Japan
| | - Sara S Jarvis
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, 7232 Greenville Avenue, Dallas, TX, 75231, USA
- Northern Arizona University, Flagstaff, AZ, USA
| | - David B Nelson
- The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Qi Fu
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, 7232 Greenville Avenue, Dallas, TX, 75231, USA.
- The University of Texas Southwestern Medical Center, Dallas, TX, USA.
| |
Collapse
|
6
|
Skow RJ, Fraser GM, Steinback CD, Davenport MH. Prenatal Exercise and Cardiovascular Health (PEACH) Study: Impact on Muscle Sympathetic Nerve (Re)Activity. Med Sci Sports Exerc 2021; 53:1101-1113. [PMID: 33315812 DOI: 10.1249/mss.0000000000002583] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
PURPOSE Women who develop gestational hypertension have evidence of elevated muscle sympathetic nerve activity (MSNA) in early pregnancy, which continues to rise after diagnosis. Exercise has been shown to play a preventative role in the development of gestational hypertension and has been shown to reduce resting and reflex MSNA in nonpregnant populations. We sought to investigate whether aerobic exercise affected the sympathetic regulation of blood pressure between the second and third trimesters of pregnancy. METHODS We conducted a randomized controlled trial of structured aerobic exercise (n = 31) compared with no intervention (control, n = 28) beginning at 16-20 wk and continuing until 34-36 wk of gestation (NCT02948439). Women in the exercise group were prescribed aerobic activity at 50%-70% of their heart rate reserve, on 3-4 d·wk-1 for 25-40 min with a 5-min warm-up and 5-min cool-down (i.e., up to 160 min total activity per week). At preintervention and postintervention assessments, data from ~10 min of quiet rest and a 3-min cold pressor test were analyzed to determine sympathetic nervous system activity and reactivity. RESULTS MSNA was obtained in 51% of assessments. Resting MSNA burst frequency and burst incidence increased across gestation (main effect of gestational age, P = 0.002). Neurovascular transduction was blunted in the control group (P = 0.024) but not in exercisers (P = 0.873) at the postintervention time point. Lastly, MSNA reactivity during the cold pressor test was not affected by gestational age or exercise (P = 0.790, interaction). CONCLUSIONS These data show that exercise attenuates both the rise in MSNA and the blunting of neurovascular transduction. This may partially explain the lower risk of developing gestational hypertension in women who are active during their pregnancies.
Collapse
Affiliation(s)
- Rachel J Skow
- Program for Pregnancy and Postpartum Health, Neurovascular Health Lab, Faculty of Kinesiology, Sport, and Recreation, Women and Children's Health Research Institute, Alberta Diabetes Institute, University of Alberta, Alberta, CANADA
| | - Graham M Fraser
- Division of BioMedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, CANADA
| | - Craig D Steinback
- Program for Pregnancy and Postpartum Health, Neurovascular Health Lab, Faculty of Kinesiology, Sport, and Recreation, Women and Children's Health Research Institute, Alberta Diabetes Institute, University of Alberta, Alberta, CANADA
| | - Margie H Davenport
- Program for Pregnancy and Postpartum Health, Neurovascular Health Lab, Faculty of Kinesiology, Sport, and Recreation, Women and Children's Health Research Institute, Alberta Diabetes Institute, University of Alberta, Alberta, CANADA
| |
Collapse
|
7
|
Skow RJ, Steele AR, Fraser GM, Davenport MH, Steinback CD. The sympathetic muscle metaboreflex is not different in the third trimester in normotensive pregnant women. J Appl Physiol (1985) 2020; 130:640-650. [PMID: 33270512 DOI: 10.1152/japplphysiol.00728.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Isometric handgrip (IHG) is used to assess sympathetic nervous system responses to exercise and may be useful at predicting hypertension in both pregnant and nonpregnant populations. We previously observed altered sympathetic nervous system control of blood pressure in late pregnancy. Therefore, we measured muscle sympathetic nerve activity (MSNA) and blood pressure during muscle metaboreflex activation (IHG) in normotensive pregnant women in the third trimester compared with in healthy nonpregnant women. Further, 19 pregnant (32 ± 3 wk gestation) and 14 nonpregnant women were matched for age, non/prepregnant body mass index (BMI), and parity. MSNA (microneurography), heart rate (ECG), and arterial blood pressure (Finometer) were continuously recorded during 10 min of rest, and then during 2 min of IHG at 30% of maximal voluntary contraction, and 2 min of postexercise circulatory occlusion (PECO). Baseline sympathetic nerve activity (SNA) was elevated in pregnant (41 ± 11 bursts/min) compared with nonpregnant women (27 ± 9 bursts/min; P = 0.005); however, the sympathetic baroreflex gain and neurovascular transduction were not different between groups (P = 0.62 and P = 0.32, respectively). During IHG and PECO, there were no significant differences in the pressor responses (ΔMAP) between groups, (P = 0.25, main effect of group) nor was the sympathetic response different between groups (interaction effect: P = 0.16, 0.25, and 0.27 for burst frequency, burst incidence, and total SNA, respectively). These data suggest that pregnant women who have maintained sympathetic baroreflex and neurovascular transduction also have similar sympathetic and pressor responses during exercise.NEW & NOTEWORTHY We compared sympathetic nervous system activation by muscle metaboreflex between pregnant women in the third trimester and nonpregnant women. We show that the sympathetic nerve activity and associated pressor responses to isometric handgrip and post-exercise circulatory occlusion are not different between third-trimester pregnant and nonpregnant women. These data suggest that unlike other reflexes (e.g., cold pressor test or head-up tilt), metaboreflex control is maintained in pregnant women.
Collapse
Affiliation(s)
- Rachel J Skow
- Program for Pregnancy and Postpartum Health, Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, Alberta, Canada
| | - Andrew R Steele
- Program for Pregnancy and Postpartum Health, Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, Alberta, Canada
| | - Graham M Fraser
- Division of Biomedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada
| | - Margie H Davenport
- Program for Pregnancy and Postpartum Health, Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, Alberta, Canada
| | - Craig D Steinback
- Program for Pregnancy and Postpartum Health, Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, Alberta, Canada
| |
Collapse
|
8
|
Hissen SL, Fu Q. Neural control of blood pressure during pregnancy in humans. Clin Auton Res 2020; 30:423-431. [PMID: 32564162 DOI: 10.1007/s10286-020-00703-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 06/10/2020] [Indexed: 12/01/2022]
Abstract
PURPOSE Previous microneurographic studies found that muscle sympathetic nerve activity (MSNA) increased in normotensive pregnant women and was even greater in women with gestational hypertension and preeclampsia during the third trimester. It is possible that sympathetic activation during the latter months of normal pregnancy helps return arterial pressure to non-pregnant levels. However, when the increase in sympathetic activity is excessive, hypertension ensues. The key question that must be addressed is whether sympathetic activation develops early during pregnancy and remains high throughout gestation, or whether this sympathetic overactivity only occurs at term, providing the substrate for preeclampsia and other pregnancy-associated cardiovascular complications. METHODS This was a literature review of autonomic neural control during pregnancy. RESULTS Recent work from our laboratory and other laboratories showed that in healthy women resting MSNA increased in early pregnancy, increased further in late pregnancy, and returned to the pre-pregnancy levels shortly after delivery. We found that women who exhibited excessive sympathetic activation during the first trimester, before any clinical signs and symptoms appeared, developed gestational hypertension at term. We also found that the level of corin, an atrial natriuretic peptide-converting enzyme, was increased in the maternal circulation, especially during late pregnancy, as a homeostatic response to elevated sympathetic activity. CONCLUSION These findings provide important insight into the neural mechanisms underlying hypertensive disorders during pregnancy. With this knowledge, early prevention or treatment targeted to the appropriate pathophysiology may be initiated, which may reduce maternal and fetal death or morbidity, as well as cardiovascular risks in women later in life.
Collapse
Affiliation(s)
- Sarah L Hissen
- Women's Heart Health Laboratory, Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, 7232 Greenville Avenue, Suite 435, Dallas, TX, 75231, USA.,Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, USA
| | - Qi Fu
- Women's Heart Health Laboratory, Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, 7232 Greenville Avenue, Suite 435, Dallas, TX, 75231, USA. .,Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, USA.
| |
Collapse
|
9
|
Brooks VL, Fu Q, Shi Z, Heesch CM. Adaptations in autonomic nervous system regulation in normal and hypertensive pregnancy. HANDBOOK OF CLINICAL NEUROLOGY 2020; 171:57-84. [PMID: 32736759 DOI: 10.1016/b978-0-444-64239-4.00003-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
There is an increase in basal sympathetic nerve activity (SNA) during normal pregnancy; this counteracts profound primary vasodilation. However, pregnancy also impairs baroreflex control of heart rate and SNA, contributing to increased mortality secondary to peripartum hemorrhage. Pregnancy-induced hypertensive disorders evoke even greater elevations in SNA, which likely contribute to the hypertension. Information concerning mechanisms is limited. In normal pregnancy, increased angiotensin II acts centrally to support elevated SNA. Hypothalamic sites, including the subfornical organ, paraventricular nucleus, and arcuate nucleus, are likely (but unproven) targets. Moreover, no definitive mechanisms for exaggerated sympathoexcitation in hypertensive pregnancy have been identified. In addition, normal pregnancy increases gamma aminobutyric acid inhibition of the rostral ventrolateral medulla (RVLM), a key brainstem site that transmits excitatory inputs to spinal sympathetic preganglionic neurons. Accumulated evidence supports a major role for locally increased production and actions of the neurosteroid allopregnanolone as one mechanism. A consequence is suppression of baroreflex function, but increased basal SNA indicates that excitatory influences predominate in the RVLM. However, many questions remain regarding other sites and factors that support increased SNA during normal pregnancy and, more importantly, the mechanisms underlying excessive sympathoexcitation in life-threatening hypertensive pregnancy disorders such as preeclampsia.
Collapse
Affiliation(s)
- Virginia L Brooks
- Department of Physiology and Pharmacology, Oregon Health & Science University, Portland, OR, United States.
| | - Qi Fu
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, TX, United States; Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Zhigang Shi
- Department of Physiology and Pharmacology, Oregon Health & Science University, Portland, OR, United States
| | - Cheryl M Heesch
- Department of Biomedical Sciences and Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, United States
| |
Collapse
|
10
|
Badrov MB, Park SY, Yoo JK, Hieda M, Okada Y, Jarvis SS, Stickford AS, Best SA, Nelson DB, Fu Q. Role of Corin in Blood Pressure Regulation in Normotensive and Hypertensive Pregnancy. Hypertension 2019; 73:432-439. [PMID: 30580684 DOI: 10.1161/hypertensionaha.118.12137] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Corin (an atrial natriuretic peptide-converting enzyme) represents a potential biomarker for gestational hypertensive disorders; yet, its role in blood pressure (BP) regulation throughout pregnancy remains unclear. We investigated the time course of change in blood corin content in relation to BP and sympathetic nerve activity throughout pregnancy. Forty-four women (29±0.9 years) participated. Following-term, 23 had low-risk (no personal history of gestational hypertensive disorders) normal pregnancies, 13 had high-risk (personal history of gestational hypertensive disorders) normal pregnancies, and 8 developed gestational hypertension. BP, heart rate, muscle sympathetic nerve activity, and serum corin were measured before pregnancy, during early (4-8 weeks) and late pregnancy (32-36 weeks), and postpartum (6-10 weeks). Overall, compared with prepregnancy, corin remained unchanged during early pregnancy, increased markedly during late pregnancy ( P<0.001), and returned to prepregnancy levels postpartum. In women who developed gestational hypertension, the change in corin from early to late pregnancy was greater than those with low-risk normal pregnancies (Δ971±134 versus Δ486±79 pg/mL; P<0.05). Throughout pregnancy, BP and muscle sympathetic nerve activity were augmented in women with gestational hypertension (all P<0.05). Finally, changes in corin from early to late pregnancy were related to all indices of BP ( R=0.454-0.551; all P<0.01) in late pregnancy, whereas burst frequency, burst incidence, and total muscle sympathetic nerve activity ( R=0.576-0.614; all P<0.001) in early pregnancy were related to changes in corin from early to late pregnancy. Corin plays a unique role in BP regulation throughout normotensive and, especially, hypertensive pregnancy and may represent a promising biomarker for determining women at high risk of adverse pregnancy outcome.
Collapse
Affiliation(s)
- Mark B Badrov
- From the Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas (M.B.B., S.Y.P., J.-K.Y., M.H., Y.O., S.S.J., A.S.S., S.A.B., Q.F.).,Internal Medicine, University of Texas Southwestern Medical Center, Dallas (M.B.B., S.Y.P., J.-K.Y., M.H., Y.O., S.S.J., A.S.S., S.A.B., D.B.N., Q.F.)
| | - Sun Young Park
- From the Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas (M.B.B., S.Y.P., J.-K.Y., M.H., Y.O., S.S.J., A.S.S., S.A.B., Q.F.).,Internal Medicine, University of Texas Southwestern Medical Center, Dallas (M.B.B., S.Y.P., J.-K.Y., M.H., Y.O., S.S.J., A.S.S., S.A.B., D.B.N., Q.F.)
| | - Jeung-Ki Yoo
- From the Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas (M.B.B., S.Y.P., J.-K.Y., M.H., Y.O., S.S.J., A.S.S., S.A.B., Q.F.).,Internal Medicine, University of Texas Southwestern Medical Center, Dallas (M.B.B., S.Y.P., J.-K.Y., M.H., Y.O., S.S.J., A.S.S., S.A.B., D.B.N., Q.F.)
| | - Michinari Hieda
- From the Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas (M.B.B., S.Y.P., J.-K.Y., M.H., Y.O., S.S.J., A.S.S., S.A.B., Q.F.).,Internal Medicine, University of Texas Southwestern Medical Center, Dallas (M.B.B., S.Y.P., J.-K.Y., M.H., Y.O., S.S.J., A.S.S., S.A.B., D.B.N., Q.F.)
| | - Yoshiyuki Okada
- From the Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas (M.B.B., S.Y.P., J.-K.Y., M.H., Y.O., S.S.J., A.S.S., S.A.B., Q.F.).,Internal Medicine, University of Texas Southwestern Medical Center, Dallas (M.B.B., S.Y.P., J.-K.Y., M.H., Y.O., S.S.J., A.S.S., S.A.B., D.B.N., Q.F.).,Department of Dentistry, Hiroshima University, Japan (Y.O.)
| | - Sara S Jarvis
- From the Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas (M.B.B., S.Y.P., J.-K.Y., M.H., Y.O., S.S.J., A.S.S., S.A.B., Q.F.).,Internal Medicine, University of Texas Southwestern Medical Center, Dallas (M.B.B., S.Y.P., J.-K.Y., M.H., Y.O., S.S.J., A.S.S., S.A.B., D.B.N., Q.F.).,Department of Biological Sciences, Northern Arizona University, Flagstaff (S.S.J.)
| | - Abigail S Stickford
- From the Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas (M.B.B., S.Y.P., J.-K.Y., M.H., Y.O., S.S.J., A.S.S., S.A.B., Q.F.).,Internal Medicine, University of Texas Southwestern Medical Center, Dallas (M.B.B., S.Y.P., J.-K.Y., M.H., Y.O., S.S.J., A.S.S., S.A.B., D.B.N., Q.F.).,Department of Health and Exercise Science, Appalachian State University, Boone, NC (A.S.S.)
| | - Stuart A Best
- From the Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas (M.B.B., S.Y.P., J.-K.Y., M.H., Y.O., S.S.J., A.S.S., S.A.B., Q.F.).,Internal Medicine, University of Texas Southwestern Medical Center, Dallas (M.B.B., S.Y.P., J.-K.Y., M.H., Y.O., S.S.J., A.S.S., S.A.B., D.B.N., Q.F.)
| | - David B Nelson
- Internal Medicine, University of Texas Southwestern Medical Center, Dallas (M.B.B., S.Y.P., J.-K.Y., M.H., Y.O., S.S.J., A.S.S., S.A.B., D.B.N., Q.F.)
| | - Qi Fu
- From the Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas (M.B.B., S.Y.P., J.-K.Y., M.H., Y.O., S.S.J., A.S.S., S.A.B., Q.F.).,Internal Medicine, University of Texas Southwestern Medical Center, Dallas (M.B.B., S.Y.P., J.-K.Y., M.H., Y.O., S.S.J., A.S.S., S.A.B., D.B.N., Q.F.)
| |
Collapse
|
11
|
Fu Q. Sex differences in sympathetic activity in obesity and its related hypertension. Ann N Y Acad Sci 2019; 1454:31-41. [PMID: 31087350 DOI: 10.1111/nyas.14095] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 03/15/2019] [Accepted: 03/21/2019] [Indexed: 01/15/2023]
Abstract
The prevalence of obesity is rapidly increasing in the United States, particularly among women. Approximately 60-70% of hypertension in adults may be directly attributed to obesity. In addition, maternal obesity is a major risk factor for hypertensive disorders during pregnancy. The underlying mechanisms for the association between obesity and cardiovascular risk are multifactorial, but activation of the sympathetic nervous system is one significant contributing factor. This brief review summarizes the current knowledge on sex differences in sympathetic activity in obesity and its related hypertension, with a focus on studies in humans. Evidence suggests that abdominal visceral fat, rather than subcutaneous fat, is related to augmented sympathetic activity regardless of sex. Race/ethnicity may affect the relationship between obesity and sympathetic activity. Obesity-related hypertension has an important neurogenic component, which is characterized by sympathetic overactivity. However, sex may influence the association between hypertension and sympathetic overactivity in obese people. Finally, both body weight and sympathetic overactivity seem to be involved in the development of gestational hypertensive disorders in women. Chronic hyperinsulinemia due to insulin resistance, high plasma levels of leptin, and/or obstructive sleep apnea may be responsible for sympathetic overactivity in obesity-related hypertension.
Collapse
Affiliation(s)
- Qi Fu
- Women's Heart Health Laboratory, Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, University of Texas Southwestern Medical Center, Dallas, Texas
| |
Collapse
|
12
|
Hissen SL, Sayed KE, Macefield VG, Brown R, Taylor CE. The Stability and Repeatability of Spontaneous Sympathetic Baroreflex Sensitivity in Healthy Young Individuals. Front Neurosci 2018; 12:403. [PMID: 29962929 PMCID: PMC6010576 DOI: 10.3389/fnins.2018.00403] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 05/25/2018] [Indexed: 01/18/2023] Open
Abstract
Spontaneous sympathetic baroreflex sensitivity (BRS) is a valuable tool for assessing how well the baroreflex buffers beat-to-beat changes in blood pressure. However, there has yet to be a study involving appropriate statistical tests to examine the stability of sympathetic BRS within an experimental session and the repeatability between separate sessions. The aim of this study was to use intra-class correlations, ordinary least products regression, and Bland–Altman analyses to examine the stability and repeatability of spontaneous sympathetic BRS assessment. In addition, the influence of recording duration on values of BRS was assessed. In eighty-four healthy young individuals (49 males, 35 females), continuous measurements of blood pressure, heart rate and muscle sympathetic nerve activity (MSNA) were recorded for 10 min. In a subgroup of 13 participants (11 male, 2 female) the measurements were repeated on a separate day. Sympathetic BRS was quantified using MSNA burst incidence (BRSinc) and total MSNA (BRStotal) for the first 5-min period, the second 5-min period, and a 2-min segment taken from the second 5-min period. Intra-class correlation coefficients indicated moderate stability in sympathetic BRSinc and BRStotal between the first and second 5-min periods in males (BRSincr = 0.63, BRStotalr = 0.78) and females (BRSincr = 0.61, BRStotalr = 0.47) with no proportional bias, but with fixed bias for BRSinc in females. When comparing the first 5-min with the 2-min period (n = 76), the intra-class correlation coefficient indicated poor to moderate repeatability in sympathetic BRSinc and BRStotal for males (BRSincr = -0.01, BRStotalr = 0.70) and females (BRSincr = 0.46, BRStotalr = 0.39). However, Bland–Altman analysis revealed a fixed bias for BRStotal in males and proportional bias for BRStotal in females, with lower BRS values for 5-min recordings. In the subgroup, intra-class correlations indicated moderate repeatability for measures of BRSinc (9 male, 2 female, r = 0.63) and BRStotal (6 male, 2 female, r = 0.68) assessed using 5-min periods recorded on separate days. However, Bland–Altman analysis indicated proportional bias for BRSinc and fixed bias for BRStotal. In conclusion, measures of spontaneous sympathetic BRS are moderately stable and repeatable within and between testing sessions in healthy young adults, provided that the same length of recording is used when making comparisons.
Collapse
Affiliation(s)
- Sarah L Hissen
- School of Science and Health, Western Sydney University, Sydney, NSW, Australia
| | - Khadigeh El Sayed
- School of Medicine, Western Sydney University, Sydney, NSW, Australia
| | - Vaughan G Macefield
- School of Medicine, Western Sydney University, Sydney, NSW, Australia.,Baker Heart and Diabetes Institute, Melbourne, VIC, Australia.,Neuroscience Research Australia, Sydney, NSW, Australia
| | - Rachael Brown
- School of Medicine, Western Sydney University, Sydney, NSW, Australia
| | - Chloe E Taylor
- School of Science and Health, Western Sydney University, Sydney, NSW, Australia.,School of Medicine, Western Sydney University, Sydney, NSW, Australia
| |
Collapse
|
13
|
Reyes LM, Usselman CW, Davenport MH, Steinback CD. Sympathetic Nervous System Regulation in Human Normotensive and Hypertensive Pregnancies. Hypertension 2018. [DOI: 10.1161/hypertensionaha.117.10766] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Laura M. Reyes
- From the Program for Pregnancy and Postpartum Health, Faculty of Kinesiology, Sport and Recreation, Women and Children’s Health Research Institute (L.M.R., C.W.U., M.H.D., C.D.S.) and Alberta Diabetes Institute (M.H.D.), University of Alberta, Edmonton, Canada
| | - Charlotte W. Usselman
- From the Program for Pregnancy and Postpartum Health, Faculty of Kinesiology, Sport and Recreation, Women and Children’s Health Research Institute (L.M.R., C.W.U., M.H.D., C.D.S.) and Alberta Diabetes Institute (M.H.D.), University of Alberta, Edmonton, Canada
| | - Margie H. Davenport
- From the Program for Pregnancy and Postpartum Health, Faculty of Kinesiology, Sport and Recreation, Women and Children’s Health Research Institute (L.M.R., C.W.U., M.H.D., C.D.S.) and Alberta Diabetes Institute (M.H.D.), University of Alberta, Edmonton, Canada
| | - Craig D. Steinback
- From the Program for Pregnancy and Postpartum Health, Faculty of Kinesiology, Sport and Recreation, Women and Children’s Health Research Institute (L.M.R., C.W.U., M.H.D., C.D.S.) and Alberta Diabetes Institute (M.H.D.), University of Alberta, Edmonton, Canada
| |
Collapse
|
14
|
Reyes LM, Davenport MH. Exercise as a therapeutic intervention to optimize fetal weight. Pharmacol Res 2018; 132:160-167. [PMID: 29684673 DOI: 10.1016/j.phrs.2018.04.016] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 03/16/2018] [Accepted: 04/18/2018] [Indexed: 12/29/2022]
Abstract
The Developmental Origins of Health and Disease suggest the in utero environment programs offspring obesity and cardiovascular disease. Therefore, there is a need to implement safe therapeutic interventions that do not involve the intake of medications or biological products during pregnancy that can improve maternal and fetal health. Prenatal exercise is established to promote maternal and fetal health. It is generally recommended that women accumulate at least 150 min per week of moderate-intensity exercise. It has been demonstrated that prenatal exercise maintains healthy weight gain and improves maternal glucose control, maternal cardiac autonomic control, placental efficiency (increases angiogenesis, downregulates genes involved in fatty acid transport and insulin transport across the placenta, and upregulates genes involved in amino acid transport across the placenta), and oxidative stress. These adaptations following exercise improve maternal metabolism and provide adequate uteroplacental perfusion. In this review, we will focus on exercise as a therapeutic intervention to optimize fetal weight. It has been established that prenatal exercise does not increase the risk of having a small for gestational age baby. To the contrary, prenatal exercise has been associated with the prevention of excessive fat accumulation in the newborn and the maintenance of fetal muscle mass.
Collapse
Affiliation(s)
- Laura M Reyes
- Program for Pregnancy and Postpartum Health, Faculty of Kinesiology, Sport and Recreation, 1-052 Li Ka Shing Centre for Health Research Innovation, Women and Children's Health Research Institute, Alberta Diabetes Institute, University of Alberta, T6G 2E1, Alberta, Canada.
| | - Margie H Davenport
- Program for Pregnancy and Postpartum Health, Faculty of Kinesiology, Sport and Recreation, 1-052 Li Ka Shing Centre for Health Research Innovation, Women and Children's Health Research Institute, Alberta Diabetes Institute, University of Alberta, T6G 2E1, Alberta, Canada.
| |
Collapse
|
15
|
Reyes LM, Usselman CW, Skow RJ, Charkoudian N, Staab JS, Davenport MH, Steinback CD. Sympathetic neurovascular regulation during pregnancy: A longitudinal case series study. Exp Physiol 2018; 103:318-323. [PMID: 29336094 DOI: 10.1113/ep086771] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 01/09/2018] [Indexed: 01/26/2023]
Abstract
NEW FINDINGS What is the main observation in this case? The main observation of this case report is that during pregnancy there is a progressive sympatho-excitation in basal conditions and under stress, which is offset by a concurrent reduction in neurovascular transduction. Strong correlations between autonomic nervous system activity and sex hormones (oestrogen and progesterone), vasopressin and aldosterone were found. What insights does it reveal? Our findings suggest that hormonal surges might be associated with central sympathetic activation. ABSTRACT The adaptations of sympathetic nerve activity (SNA) during pregnancy remain poorly understood. An increase in blood volume, cardiac output and SNA, with a concomitant drop in total peripheral resistance (TPR), suggest that during pregnancy there is a reduced transduction of SNA into TPR. Most of these findings have originated from cross-sectional studies; thus, we conducted a longitudinal assessment of SNA and TPR in two participants. Measurements were made before pregnancy (early follicular phase), on four occasions during pregnancy and at 2 months postpartum. Mean arterial pressure and cardiac output were used to calculate TPR. The SNA was measured using microneurography (peroneal nerve). There was a gestation-dependent increase in SNA burst frequency (r2 = 0.96, P = 0.009). Neurovascular transduction, however, decreased by 53% in both women. Sympathetic hyperactivity was reversed postpartum, whereas neurovascular transduction remained lower. These longitudinal data highlight the progressive sympatho-excitation of pregnancy, which is offset by a concurrent reduction in neurovascular transduction.
Collapse
Affiliation(s)
- Laura M Reyes
- Program for Pregnancy and Postpartum Health, Faculty of Kinesiology, Sport and Recreation, University of Alberta, Edmonton, AB, Canada.,Physical Activity and Diabetes Laboratory, Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, AB, Canada
| | - Charlotte W Usselman
- Program for Pregnancy and Postpartum Health, Faculty of Kinesiology, Sport and Recreation, University of Alberta, Edmonton, AB, Canada.,Physical Activity and Diabetes Laboratory, Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, AB, Canada
| | - Rachel J Skow
- Program for Pregnancy and Postpartum Health, Faculty of Kinesiology, Sport and Recreation, University of Alberta, Edmonton, AB, Canada.,Physical Activity and Diabetes Laboratory, Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, AB, Canada
| | - Nisha Charkoudian
- US Army Research Institute of Environmental Medicine, Natick, MA, USA
| | - Jeffery S Staab
- US Army Research Institute of Environmental Medicine, Natick, MA, USA
| | - Margie H Davenport
- Program for Pregnancy and Postpartum Health, Faculty of Kinesiology, Sport and Recreation, University of Alberta, Edmonton, AB, Canada.,Physical Activity and Diabetes Laboratory, Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, AB, Canada
| | - Craig D Steinback
- Program for Pregnancy and Postpartum Health, Faculty of Kinesiology, Sport and Recreation, University of Alberta, Edmonton, AB, Canada.,Physical Activity and Diabetes Laboratory, Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, AB, Canada
| |
Collapse
|
16
|
Hemodynamic and Electrocardiographic Aspects of Uncomplicated Singleton Pregnancy. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1065:413-431. [PMID: 30051399 DOI: 10.1007/978-3-319-77932-4_26] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Pregnancy is associated with significant changes in maternal hemodynamics, which are triggered by profound systemic vasodilation and mediated through the autonomic nervous system as well as the renin-angiotensin-aldosterone system. Vascular function changes to help accommodate an increase in intravascular volume due to blood volume expansion associated with pregnancy while maintaining the efficiency of ventricular-arterial coupling and diastolic perfusion pressure. The heart undergoes physiological (eccentric) hypertrophy due to increased volume load and cardiac stroke work, whereas the functional change of the left ventricle remains controversial. There are changes in cardiac electrical activity during pregnancy which can be detected in the electrocardiogram that are not related to disease. Sympathetic activation is a common phenomenon during uncomplicated pregnancy and may be a compensatory mechanism induced by profound systemic vasodilation and a decrease in mean arterial pressure. Despite marked sympathetic activation, vasoconstrictor responsiveness is blunted during uncomplicated pregnancy. There are race and ethnic differences in maternal hemodynamic adaptations to uncomplicated pregnancy, which may be attributed to differences in socioeconomic status or in prevalence rates of cardiovascular risk factors.
Collapse
|