Effect of aging on the cardiovascular regulatory systems in healthy women

Lavi, Shahar; Nevo, Ori; Thaler, Israel; Rosenfeld, Rimma; Dayan, Lior; Hirshoren, Nir; Gepstein, Lior; Jacob, Giris

doi:10.1152/ajpregu.00352.2006

Cited by 91 publications

(69 citation statements)

References 46 publications

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“…A greater percentage of lowthreshold Ah-type myelinated afferents may account for the predominant vagal tone in females compared with agematched males (8). A recent study by Lavi et al (28) has documented that numerous indexes of vagal cardiac tone in postmenopausal women were significantly decreased from those of premenopausal women. There is growing support in the literature for the suggestion that a transition from vagal parasympathetic to sympathetic control of neurocirculation may contribute to the increased cardiovascular morbidity of females with aging (28).…”

Section: Discussionmentioning

confidence: 98%

“…A recent study by Lavi et al (28) has documented that numerous indexes of vagal cardiac tone in postmenopausal women were significantly decreased from those of premenopausal women. There is growing support in the literature for the suggestion that a transition from vagal parasympathetic to sympathetic control of neurocirculation may contribute to the increased cardiovascular morbidity of females with aging (28). OVX female rats have been shown to exhibit enhanced sympathetic activation and attenuated vagal tone, and it has been shown that acute injection of 17␤-estradiol can enhance vagally mediated cardiovascular reflexes and autonomic tone (11,44).…”

Section: Discussionmentioning

confidence: 98%

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17β-Estradiol restores excitability of a sexually dimorphic subset of myelinated vagal afferents in ovariectomized rats

Qiao

et al. 2009

American Journal of Physiology-Cell Physiology

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Qiao GF, Li BY, Lu YJ, Fu YL, Schild JH. 17␤-Estradiol restores excitability of a sexually dimorphic subset of myelinated vagal afferents in ovariectomized rats. Am J Physiol Cell Physiol 297: C654 -C664, 2009. First published July 1, 2009 doi:10.1152/ajpcell.00059.2009.-We recently identified a myelinated vagal afferent subpopulation (Ah type) far more prevalent in female than male rats and showed that this difference extends to functionally specific visceral sensory afferents, baroreceptors of the aortic arch. Excitability of myelinated Ah-type afferents is markedly reduced after ovariectomy (OVX). Here we tested the hypothesis that 17␤-estradiol can selectively restore excitability of these sex-specific vagal afferents. Acutely isolated vagal afferent neurons (VGN) from intact and OVX adult female rats were used with patch-clamp technique and current-clamp protocols to assess the effect of acute application of 17␤-estradiol on neuronal excitability. At over physiologically relevant 17␤-estradiol concentrations for rat (1-10 nM) excitability of myelinated Ah-type vagal afferents is restored to discharge frequencies comparable to those in intact females, albeit with some interesting differences related to burst and sustained patterns of neuronal discharge. Restoration of excitability occurs within 3 min of hormone application and is stereo specific, because 1,000 nM 17␣-estradiol fails to alter excitability. Furthermore, activation of G protein-coupled estrogen receptor GPR30 with highly selective agonist G-1 similarly restores excitability of Ah-type afferents. The effectiveness of 17␤-estradiol and G-1 is completely eliminated by application of high-affinity estrogen receptor ligand ICI-182,780. 17␤-Estradiol conjugated with BSA is ϳ70% as effective as 17␤-estradiol alone in restoring Ah-type VGN excitability. These data support our conclusions that the cellular mechanisms leading to rapid restoration of neuronal excitability of myelinated Ah-type VGN after OVX occur, at least in part, via membrane-bound estrogen receptors. We contend that recovery of high-frequency discharge at physiologically relevant 17␤-estradiol concentrations implies that this unique subtype of low-threshold myelinated vagal afferent may account for some of the sex-related differences in visceral organ system function. Sex differences in cardiovascular and gastrointestinal function and the potential role of GPR30 in modulation of sex-specific myelinated Ah-type vagal afferents are discussed. sensory afferent; visceral afferent; estrogen receptor; GPR30; ovariectomy VISCERAL AFFERENTS with cell bodies in the vagal ganglia innervate a functionally diverse range of organs associated with the cardiovascular, gastrointestinal, and pulmonary systems. Vagal afferent mediation of the reflexogenic properties of the autonomic nervous system (ANS) in addition to visceral sensation is well recognized (for review see Ref. 55). Because the peripheral sensory terminals can be influenced by a wide range of endogenous chemicals released as a consequenc...

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Section: Discussionmentioning

confidence: 98%

Section: Discussionmentioning

confidence: 98%

17β-Estradiol restores excitability of a sexually dimorphic subset of myelinated vagal afferents in ovariectomized rats

Qiao

et al. 2009

American Journal of Physiology-Cell Physiology

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“…Investigations of men and women from 23-77 yr of age indicated that the heart rate response to tilt was reduced with aging, but vascular responses appeared to be enhanced to protect against low blood pressure (17,32). A study that focused on postmenopausal women also reported a reduction in arterial baroreflex responsiveness and heart rate control characterized by greater sympathetic and reduced parasympathetic modulation (33). Another investigation revealed that, during lower body negative pressure (LBNP), postmenopausal women had higher systolic (SBP) and mean arterial blood pressures (MAP) with an attenuated increase in heart rate compared with premenopausal women (21).…”

mentioning

confidence: 99%

Hemodynamics and brain blood flow during posture change in younger women and postmenopausal women compared with age-matched men

Edgell

Robertson

Hughson

2012

Journal of Applied Physiology

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Edgell H, Robertson AD, Hughson RL. Hemodynamics and brain blood flow during posture change in younger women and postmenopausal women compared with age-matched men. J Appl Physiol 112: 1482-1493, 2012. First published February 23, 2012 doi:10.1152/japplphysiol.01204.2011.-Increased incidence of orthostatic hypotension and presyncopal symptoms in young women could be related to hormonal factors that might be isolated by comparing cardiovascular and cerebrovascular responses to postural change in young and older men and women. Seven young women, 11 young men, 10 older women (Ͼ1 yr postmenopausal, no hormone therapy), and 9 older men participated in a supine-to-sit-to-stand test while measuring systemic hemodynamics, end-tidal PCO2, and blood flow velocity of the middle cerebral artery (MCA). Women had a greater reduction in stroke volume index compared with age-matched men (change from supine to standing: young women: Ϫ22.9 Ϯ 1.6 ml/m 2 ; young men: Ϫ14.4 Ϯ 2.4 ml/m 2 ; older women: Ϫ17.4 Ϯ 3.3 ml/m 2 ; older men: Ϫ13.8 Ϯ 2.2 ml/m 2 ). This was accompanied by offsetting changes in heart rate, particularly in young women, resulting in no age or sex differences in cardiac output index. Mean arterial pressure (MAP) was higher in older subjects and increased with movement to upright postures. Younger men and women had higher forearm vascular resistance that increased progressively in the upright posture compared with older men and women. There was no difference between sexes or ages in total peripheral resistance index. Women had higher MCA velocity, but both sexes had reduced MCA velocity while upright, which was a function of reduced blood pressure at the MCA and a significant reduction in end-tidal PCO2. The reductions in stroke volume index suggested impaired venous return in women, but augmented responses of heart rate and forearm vascular resistance protected MAP in younger women. Overall, these results showed significant sex and age-related differences, but compensatory mechanisms preserved MAP and MCA velocity in young women. cerebrovascular; sex; age; orthostatic ORTHOSTATIC HYPOTENSION (a condition that sometimes leads to fainting) is an important and sometimes dangerous condition that particularly affects young women during daily life, as reflected by admission to emergency rooms (51). It has been speculated that female sex hormones might modulate reflex neural or vascular properties, resulting in the greater incidence of orthostatic hypotension in young women (5,14,15,52,69). An additional indication of impaired orthostatic responses in women includes the observation that women have a greater propensity towards postural orthostatic tachycardia syndrome (18, 60).Contrary to observations for young women, clinical evidence supports the concept that orthostatic hypotension occurs less frequently in women ages 40 -60 yr (many of whom could be postmenopausal) (51). Investigations of men and women from 23-77 yr of age indicated that the heart rate response to tilt was reduced with aging, but vascular responses a...

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“…For example, aging of healthy women is associated with a decrease in the parasympathetic modulation of the heart in the setting of a preserved sympathetic tone leading to a net predominance of sympathetic control. 2 Decreased baroreflex buffering ability is also seen with advancing age. 2 Moreover, imaging studies after adjustment for perfusion changes in healthy hearts have shown that cardiac uptake 1 activity decreases with aging.…”

mentioning

confidence: 99%

“…2 Decreased baroreflex buffering ability is also seen with advancing age. 2 Moreover, imaging studies after adjustment for perfusion changes in healthy hearts have shown that cardiac uptake 1 activity decreases with aging. 3 These observations corroborate well with the known evidence on the increased cardiac norepinephrine spillover during normal aging 4 and potentially make older hearts appear pre-disposed to catecholamine exposure in a given stressful situation.…”

mentioning

confidence: 99%

Age Bias and Individual Variability in Stress Cardiomyopathy Syndromes: Mere Observations or Answers?

Singh

2008

J GEN INTERN MED

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the age-distribution and phenotypic variation seen in the syndrome that may be crucial in context of the proposed catecholamine-mediated mechanism.The majority of the reported patients with stress cardiomyopathy syndromes have mean age >50 years at presentation. The answer, perhaps, lies in the mechanism itself. Many physiological observations in apparently healthy subjects point towards age-related vulnerability to sympathetic perturbations. For example, aging of healthy women is associated with a decrease in the parasympathetic modulation of the heart in the setting of a preserved sympathetic tone leading to a net predominance of sympathetic control.2 Decreased baroreflex buffering ability is also seen with advancing age. 2 Moreover, imaging studies after adjustment for perfusion changes in healthy hearts have shown that cardiac uptake 1 activity decreases with aging. 3 These observations corroborate well with the known evidence on the increased cardiac norepinephrine spillover during normal aging 4 and potentially make older hearts appear pre-disposed to catecholamine exposure in a given stressful situation. 3Why is it that while stress is ubiquitous, transient cardiomyopathy syndromes are not, and why are differences in pattern of contractile abnormalities seen? These points are worth exploring in the review for they have wide implications. A recent prospective genotype study of 182 patients of subarachnoid hemorrhage (SAH) by Zaroff and colleagues provides valuable insights in this regard.5 They demonstrated that certain adrenoreceptor polymorphisms that are known to increase presynaptic catecholamine release or are associated with increased heart failure/adverse cardiovascular events in elderly are also associated with an increased risk of wall motion abnormalities, degree of troponin release and systolic dysfunction in SAH. Thus, apart from providing a basis for individual susceptibility and variable wall motion abnormality, indirect evidence on a unifying mechanism (neurocardiogenic) of the stress cardiomyopathy syndromes was also highlighted in the important study and warrants future research.Nishith K. Singh, MD, Southern Illinois University School of Medicine, 1617 Westchester Blvd#2, Springfield, IL 62704, USA; (e-mail: nishith_singh2007@yahoo.com).

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Effect of aging on the cardiovascular regulatory systems in healthy women

Cited by 91 publications

References 46 publications

17β-Estradiol restores excitability of a sexually dimorphic subset of myelinated vagal afferents in ovariectomized rats

17β-Estradiol restores excitability of a sexually dimorphic subset of myelinated vagal afferents in ovariectomized rats

Hemodynamics and brain blood flow during posture change in younger women and postmenopausal women compared with age-matched men

Age Bias and Individual Variability in Stress Cardiomyopathy Syndromes: Mere Observations or Answers?

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