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Asunción-Alvarez D, Palacios J, Ybañez-Julca RO, Rodriguez-Silva CN, Nwokocha C, Cifuentes F, Greensmith DJ. Calcium signaling in endothelial and vascular smooth muscle cells: sex differences and the influence of estrogens and androgens. Am J Physiol Heart Circ Physiol 2024; 326:H950-H970. [PMID: 38334967 DOI: 10.1152/ajpheart.00600.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 02/05/2024] [Accepted: 02/05/2024] [Indexed: 02/10/2024]
Abstract
Calcium signaling in vascular endothelial cells (ECs) and smooth muscle cells (VSMCs) is essential for the regulation of vascular tone. However, the changes to intracellular Ca2+ concentrations are often influenced by sex differences. Furthermore, a large body of evidence shows that sex hormone imbalance leads to dysregulation of Ca2+ signaling and this is a key factor in the pathogenesis of cardiovascular diseases. In this review, the effects of estrogens and androgens on vascular calcium-handling proteins are discussed, with emphasis on the associated genomic or nongenomic molecular mechanisms. The experimental models from which data were collected were also considered. The review highlights 1) in female ECs, transient receptor potential vanilloid 4 (TRPV4) and mitochondrial Ca2+ uniporter (MCU) enhance Ca2+-dependent nitric oxide (NO) generation. In males, only transient receptor potential canonical 3 (TRPC3) plays a fundamental role in this effect. 2) Female VSMCs have lower cytosolic Ca2+ levels than males due to differences in the activity and expression of stromal interaction molecule 1 (STIM1), calcium release-activated calcium modulator 1 (Orai1), calcium voltage-gated channel subunit-α1C (CaV1.2), Na+-K+-2Cl- symporter (NKCC1), and the Na+/K+-ATPase. 3) When compared with androgens, the influence of estrogens on Ca2+ homeostasis, vascular tone, and incidence of vascular disease is better documented. 4) Many studies use supraphysiological concentrations of sex hormones, which may limit the physiological relevance of outcomes. 5) Sex-dependent differences in Ca2+ signaling mean both sexes ought to be included in experimental design.
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Affiliation(s)
- Daniel Asunción-Alvarez
- Laboratorio de Bioquímica Aplicada, Química y Farmacia, Facultad de Ciencias de la Salud, Universidad Arturo Prat, Iquique, Chile
| | - Javier Palacios
- Laboratorio de Bioquímica Aplicada, Química y Farmacia, Facultad de Ciencias de la Salud, Universidad Arturo Prat, Iquique, Chile
| | - Roberto O Ybañez-Julca
- Departamento de Farmacología, Facultad de Farmacia y Bioquímica, Universidad Nacional de Trujillo, Trujillo, Perú
| | - Cristhian N Rodriguez-Silva
- Departamento de Farmacología, Facultad de Farmacia y Bioquímica, Universidad Nacional de Trujillo, Trujillo, Perú
| | - Chukwuemeka Nwokocha
- Department of Basic Medical Sciences Physiology Section, Faculty of Medical Sciences, The University of the West Indies, Kingston, Jamaica
| | - Fredi Cifuentes
- Laboratorio de Fisiología Experimental (EphyL), Instituto Antofagasta (IA), Universidad de Antofagasta, Antofagasta, Chile
| | - David J Greensmith
- Biomedical Research Centre, School of Science, Engineering and Environment, The University of Salford, Salford, United Kingdom
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Ramírez-Hernández D, López-Sánchez P, Lezama-Martínez D, Kuyoc-Arroyo NM, Rodríguez-Rodríguez JE, Fonseca-Coronado S, Valencia-Hernández I, Flores-Monroy J. Timing Matters: Effects of Early and Late Estrogen Replacement Therapy on Glucose Metabolism and Vascular Reactivity in Ovariectomized Aged Wistar Rats. J Renin Angiotensin Aldosterone Syst 2023; 2023:6683989. [PMID: 38025203 PMCID: PMC10665112 DOI: 10.1155/2023/6683989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 10/16/2023] [Accepted: 11/06/2023] [Indexed: 12/01/2023] Open
Abstract
Cardiovascular disease incidence increases after menopause due to the loss of estrogen cardioprotective effects. However, there are conflicting data regarding the timing of estrogen therapy (ERT) and its effect on vascular dysfunction associated with impaired glucose metabolism. The aim of this work was to evaluate the effect of early and late ERT on blood glucose/insulin balance and vascular reactivity in aged ovariectomized Wistar rats. Eighteen-month-old female Wistar rats were randomized as follows: (1) sham, (2) 10-week postovariectomy (10 w), (3) 10 w postovariectomy+early estradiol therapy (10 w-early E2), (4) 20-week postovariectomy (20 w), and (5) 20-week postovariectomy+late estradiol therapy (20 w-late E2). Early E2 was administered 3 days after ovariectomy and late therapy after 10 weeks, in both groups. 17β-Estradiol (E2) was administered daily for 10 weeks (5 μg/kg/day). Concentration-response curves to angiotensin II, KCl, and acetylcholine (ACh) were performed. Heart rate (HR), diastolic and systolic blood pressure (DBP and SBP), glucose, insulin, HOMA-IR, and nitric oxide (NO) levels were determined. Higher glucose levels were found in all groups compared to the sham group, except the 20 w-late E2 group. Insulin was increased in all ovariectomized groups compared to sham. The HOMA-IR index showed insulin resistance in all ovariectomized groups, except for the 10 w-early E2 group. The 10 w-early E2 group increased NO levels vs. the 10 w group. After 10 w postovariectomy, the vascular response to KCl and Ach increases, despite early E2 administration. Early and late E2 treatment decreased vascular reactivity to Ang II. At 20-week postovariectomy, DBP increased, even with E2 administration, while SBP and HR remained unchanged. The effects of E2 therapy on blood glucose/insulin balance and vascular reactivity depend on the timing of therapy. Early ERT may provide some protective effects on insulin resistance and vascular function, whereas late ERT may not have the same benefits.
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Affiliation(s)
- Diana Ramírez-Hernández
- Myocardial Pharmacology Laboratory, Faculty of Higher Studies Cuautitlan, National Autonomous University of Mexico, 54740 State of Mexico, Mexico
| | - Pedro López-Sánchez
- Laboratorio de Farmacología Molecular, Escuela Superior de Medicina, Instituto Politécnico Nacional, 11340 Ciudad de México, Mexico
| | - Diego Lezama-Martínez
- Myocardial Pharmacology Laboratory, Faculty of Higher Studies Cuautitlan, National Autonomous University of Mexico, 54740 State of Mexico, Mexico
| | - Neidy M. Kuyoc-Arroyo
- Myocardial Pharmacology Laboratory, Faculty of Higher Studies Cuautitlan, National Autonomous University of Mexico, 54740 State of Mexico, Mexico
| | - Jessica E. Rodríguez-Rodríguez
- Biological Pharmaceutical Chemist Career, Faculty of Higher Education Zaragoza, National Autonomous University of Mexico, Batalla 5 de Mayo S/N, Ejército de Oriente, Iztapalapa, 09230 Mexico City, Mexico
- Laboratory 7, Biomedicine Unit, Faculty of Higher Education Iztacala, National Autonomous University of Mexico, Avenida de los Barrios 1, Los Reyes Ixtacala, 54090 Tlalnepantla de Baz, Mexico
| | - Salvador Fonseca-Coronado
- Immunology Laboratory, Faculty of Higher Studies Cuautitlan, National Autonomous University of Mexico, 54740 State of Mexico, Mexico
| | - Ignacio Valencia-Hernández
- Laboratorio de Farmacología Cardiovascular, Escuela Superior de Medicina, Instituto Politécnico Nacional, 11340 Ciudad de México, Mexico
| | - Jazmin Flores-Monroy
- Myocardial Pharmacology Laboratory, Faculty of Higher Studies Cuautitlan, National Autonomous University of Mexico, 54740 State of Mexico, Mexico
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Jiao L, Machuki JO, Wu Q, Shi M, Fu L, Adekunle AO, Tao X, Xu C, Hu X, Yin Z, Sun H. Estrogen and calcium handling proteins: new discoveries and mechanisms in cardiovascular diseases. Am J Physiol Heart Circ Physiol 2020; 318:H820-H829. [PMID: 32083972 DOI: 10.1152/ajpheart.00734.2019] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Estrogen deficiency is considered to be an important factor leading to cardiovascular diseases (CVDs). Indeed, the prevalence of CVDs in postmenopausal women exceeds that of premenopausal women and men of the same age. Recent research findings provide evidence that estrogen plays a pivotal role in the regulation of calcium homeostasis and therefore fine-tunes normal cardiomyocyte contraction and relaxation processes. Disruption of calcium homeostasis is closely associated with the pathological mechanism of CVDs. Thus, this paper maps out and summarizes the effects and mechanisms of estrogen on calcium handling proteins in cardiac myocytes, including L-type Ca2+ channel, the sarcoplasmic reticulum Ca2+ release channel named ryanodine receptor, sarco(endo)plasmic reticulum Ca2+-ATPase, and sodium-calcium exchanger. In so doing, we provide theoretical and experimental evidence for the successful design of estrogen-based prevention and treatment therapies for CVDs.
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Affiliation(s)
- Lijuan Jiao
- Department of Physiology, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | | | - Qi Wu
- Department of Physiology, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Mingjin Shi
- Department of Physiology, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Lu Fu
- Department of Physiology, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | | | - Xi Tao
- Department of Physiology, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Chenxi Xu
- Department of Physiology, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Xide Hu
- Department of Physiology, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Zeyuan Yin
- Department of Physiology, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Hong Sun
- Department of Physiology, Xuzhou Medical University, Xuzhou, Jiangsu, China
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Hadjadj L, Pál É, Monori-Kiss A, Sziva RE, Korsós-Novák Á, Mária Horváth E, Benkő R, Magyar A, Magyar P, Benyó Z, Nádasy GL, Várbíró S. Vitamin D deficiency and androgen excess result eutrophic remodeling and reduced myogenic adaptation in small cerebral arterioles in female rats. Gynecol Endocrinol 2019; 35:529-534. [PMID: 30623742 DOI: 10.1080/09513590.2018.1554037] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Vitamin D (vitD) insufficiency affects 1 billion people worldwide. Androgen excess (AE) occurs in 8% of fertile females. There are few data about the combined effect of vitD deficiency and AE on the early biomechanical changes of cerebral arterioles in fertile-aged female. Forty-six adolescent female Wistar rats (21-28 day-old, weighing 90-110 g) were grouped randomly in four groups: vitD supplemented groups with and without transdermal testosterone (T) treatment, as well as vitD deficient groups also with and without transdermal T (n = 11 or 12, in all cases). After 8 weeks of treatment, anterior cerebral arterioles (in vivo diameter of 90-130 µm) were obtained and cylindrical segments were examined by pressure arteriography. Myogenic tone, tangential stress and incremental elastic moduli were computed and statistically analyzed. Elastic density was studied on resorcin-fuchsin-stained histological section. VitD deficiency with T treatment resulted in significantly lower inner radii and higher wall thickness values with reduced tangential stress and increased elastic fiber density. VitD deficiency reduced myogenic tone at higher intraluminar pressures (>110 mmHg). Our conclusion is that plasma vitD level is an important factor in the control of myogenic tone in cerebral resistance arteries. AE and vitD deficiency acting parallel induce remodeling of their wall.
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Affiliation(s)
- Leila Hadjadj
- a Faculty of Medicine , Institute of Human Physiology and Clinical Experimental Research, Semmelweis University , Budapest , Hungary
| | - Éva Pál
- a Faculty of Medicine , Institute of Human Physiology and Clinical Experimental Research, Semmelweis University , Budapest , Hungary
| | - Anna Monori-Kiss
- a Faculty of Medicine , Institute of Human Physiology and Clinical Experimental Research, Semmelweis University , Budapest , Hungary
| | - Réka Eszter Sziva
- b 2nd Department of Obstetrics and Gynecology, Faculty of Medicine , Semmelweis University , Budapest , Hungary
| | - Ágnes Korsós-Novák
- c Department of Pathology , Jász-Nagykun-Szolnok Megyei Hetényi Géza Regional Hospital , Szolnok , Hungary
| | - Eszter Mária Horváth
- d Department of Physiology, Faculty of Medicine, Semmelweis University , Budapest , Hungary
| | - Rita Benkő
- d Department of Physiology, Faculty of Medicine, Semmelweis University , Budapest , Hungary
| | - Attila Magyar
- e Department of Anatomy, Histology and Embryology , Semmelweis University , Faculty of Medicine , Budapest , Hungary
| | - Péter Magyar
- f Department of Radiology , Semmelweis University , Faculty of Medicine , Budapest , Hungary
| | - Zoltán Benyó
- a Faculty of Medicine , Institute of Human Physiology and Clinical Experimental Research, Semmelweis University , Budapest , Hungary
| | - György L Nádasy
- d Department of Physiology, Faculty of Medicine, Semmelweis University , Budapest , Hungary
| | - Szabolcs Várbíró
- b 2nd Department of Obstetrics and Gynecology, Faculty of Medicine , Semmelweis University , Budapest , Hungary
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Pabbidi MR, Kuppusamy M, Didion SP, Sanapureddy P, Reed JT, Sontakke SP. Sex differences in the vascular function and related mechanisms: role of 17β-estradiol. Am J Physiol Heart Circ Physiol 2018; 315:H1499-H1518. [DOI: 10.1152/ajpheart.00194.2018] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The incidence of cardiovascular disease (CVD) is lower in premenopausal women but increases with age and menopause compared with similarly aged men. Based on the prevalence of CVD in postmenopausal women, sex hormone-dependent mechanisms have been postulated to be the primary factors responsible for the protection from CVD in premenopausal women. Recent Women’s Health Initiative studies, Cochrane Review studies, the Early Versus Late Intervention Trial with Estradiol Study, and the Kronos Early Estrogen Prevention Study have suggested that beneficial effects of hormone replacement therapy (HRT) are seen in women of <60 yr of age and if initiated within <10 yr of menopause. In contrast, the beneficial effects of HRT are not seen in women of >60 yr of age and if commenced after 10 yr of menopause. The higher incidence of CVD and the failure of HRT in postmenopausal aged women could be partly associated with fundamental differences in the vascular structure and function between men and women and in between pre- and postmenopausal women, respectively. In this regard, previous studies from human and animal studies have identified several sex differences in vascular function and associated mechanisms. The female sex hormone 17β-estradiol regulates the majority of these mechanisms. In this review, we summarize the sex differences in vascular structure, myogenic properties, endothelium-dependent and -independent mechanisms, and the role of 17β-estradiol in the regulation of vascular function.
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Affiliation(s)
- Mallikarjuna R. Pabbidi
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Maniselvan Kuppusamy
- Division of Endocrinology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Sean P. Didion
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Padmaja Sanapureddy
- Department of Primary Care and Medicine, G. V. (Sonny) Montgomery Veterans Affairs Medical Center, Jackson, Mississippi
| | - Joey T. Reed
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Sumit P. Sontakke
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
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Hill BJF, Dalton RJ, Joseph BK, Thakali KM, Rusch NJ. 17β-estradiol reduces Ca v 1.2 channel abundance and attenuates Ca 2+ -dependent contractions in coronary arteries. Pharmacol Res Perspect 2018; 5. [PMID: 28971605 PMCID: PMC5625162 DOI: 10.1002/prp2.358] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 07/05/2017] [Accepted: 08/04/2017] [Indexed: 12/21/2022] Open
Abstract
One mechanism by which the female sex may protect against elevated coronary vascular tone is inhibition of Ca2+ entry into arterial smooth muscle cells (ASMCs). In vitro findings confirm that high estrogen concentrations directly inhibit voltage‐dependent Cav1.2 channels in coronary ASMCs. For this study, we hypothesized that the nonacute, in vitro exposure of coronary arteries to a low concentration of 17β‐estradiol (17βE) reduces the expression of Cav1.2 channel proteins in coronary ASMCs. Segments of the right coronary artery obtained from sexually mature female pigs were mounted for isometric tension recording. As expected, our results indicate that high concentrations (≥10 μmol/L) of 17βE acutely attenuated Ca2+‐dependent contractions to depolarizing KCl stimuli. Interestingly, culturing coronary arteries for 24 h in a 10,000‐fold lower concentration (1 nmol/L) of 17βE also attenuated KCl‐induced contractions and reduced the contractile response to the Cav1.2 agonist, FPL64176, by 50%. Western blots revealed that 1 nmol/L 17βE decreased protein expression of the pore‐forming α1C subunit (Cavα) of the Cav1.2 channel by 35%; this response did not depend on an intact endothelium. The 17βE‐induced loss of Cavα protein in coronary arteries was prevented by the estrogen ERα/ERβ antagonist, ICI 182,780, whereas the GPER antagonist, G15, did not prevent it. There was no effect of 1 nmol/L 17βE on Cavα transcript expression. We conclude that 17βE reduces Cav1.2 channel abundance in isolated coronary arteries by a posttranscriptional process. This unrecognized effect of estrogen may confer physiological protection against the development of abnormal Ca2+‐dependent coronary vascular tone.
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Affiliation(s)
- Brent J F Hill
- Department of Biology, University of Central Arkansas Conway, Conway, Arkansas
| | - Robin J Dalton
- Department of Biology, University of Central Arkansas Conway, Conway, Arkansas
| | - Biny K Joseph
- Department of Pharmacology and Toxicology, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Keshari M Thakali
- Arkansas Children's Nutrition Center & Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Nancy J Rusch
- Department of Pharmacology and Toxicology, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, Arkansas
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Yang HY, Firth JM, Francis AJ, Alvarez-Laviada A, MacLeod KT. Effect of ovariectomy on intracellular Ca 2+ regulation in guinea pig cardiomyocytes. Am J Physiol Heart Circ Physiol 2017; 313:H1031-H1043. [PMID: 28778911 DOI: 10.1152/ajpheart.00249.2017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 07/17/2017] [Accepted: 08/02/2017] [Indexed: 01/30/2023]
Abstract
This study addressed the hypothesis that long-term deficiency of ovarian hormones after ovariectomy (OVx) alters cellular Ca2+-handling mechanisms in the heart, resulting in the formation of a proarrhythmic substrate. It also tested whether estrogen supplementation to OVx animals reverses any alterations to cardiac Ca2+ handling and rescues proarrhythmic behavior. OVx or sham operations were performed on female guinea pigs using appropriate anesthetic and analgesic regimes. Pellets containing 17β-estradiol (1 mg, 60-day release) were placed subcutaneously in selected OVx animals (OVx + E). Cardiac myocytes were enzymatically isolated, and electrophysiological measurements were conducted with a switch-clamp system. In fluo-4-loaded cells, Ca2+ transients were 20% larger, and fractional sarcoplasmic reticulum (SR) Ca2+ release was 7% greater in the OVx group compared with the sham group. Peak L-type Ca2+ current was 16% larger in OVx myocytes with channel inactivation shifting to more positive membrane potentials, creating a larger "window" current. SR Ca2+ stores were 22% greater in the OVx group, and these cells showed a higher frequency of Ca2+ sparks and waves and shorter wave-free intervals. OVx myocytes showed higher frequencies of early afterdepolarizations, and a greater percentage of these cells showed delayed afterdepolarizations after exposure to isoprenaline compared with sham myocytes. The altered Ca2+ regulation occurring in the OVx group was not observed in the OVx + E group. These findings suggest that long-term deprivation of ovarian hormones in guinea pigs lead to changes in myocyte Ca2+-handling mechanisms that are considered proarrhythmogenic. 17β-Estradiol replacement prevented these adverse effects.NEW & NOTEWORTHY Ovariectomized guinea pig cardiomyocytes have higher frequencies of Ca2+ waves, and isoprenaline-challenged cells display more early afterdepolarizations, delayed afterdepolarizations, and extra beats compared with sham myocytes. These alterations to Ca2+ regulation were not observed in myocytes from ovariectomized guinea pigs supplemented with 17β-estradiol, suggesting that ovarian hormone deficiency modifies cardiac Ca2+ regulation, potentially creating proarrhythmic substrates.
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Affiliation(s)
- Hsiang-Yu Yang
- National Heart and Lung Institute, Imperial College London, London, United Kingdom; and.,Division of Cardiovascular Surgery, Department of Surgery, Tri-Service General Hospital, National Defence Medical Center, Taipei, Taiwan
| | - Jahn M Firth
- National Heart and Lung Institute, Imperial College London, London, United Kingdom; and
| | - Alice J Francis
- National Heart and Lung Institute, Imperial College London, London, United Kingdom; and
| | - Anita Alvarez-Laviada
- National Heart and Lung Institute, Imperial College London, London, United Kingdom; and
| | - Kenneth T MacLeod
- National Heart and Lung Institute, Imperial College London, London, United Kingdom; and
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Hormones and sex differences: changes in cardiac electrophysiology with pregnancy. Clin Sci (Lond) 2017; 130:747-59. [PMID: 27128800 DOI: 10.1042/cs20150710] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Accepted: 02/01/2016] [Indexed: 11/17/2022]
Abstract
Disruption of cardiac electrical activity resulting in palpitations and syncope is often an early symptom of pregnancy. Pregnancy is a time of dramatic and dynamic physiological and hormonal changes during which numerous demands are placed on the heart. These changes result in electrical remodelling which can be detected as changes in the electrocardiogram (ECG). This gestational remodelling is a very under-researched area. There are no systematic large studies powered to determine changes in the ECG from pre-pregnancy, through gestation, and into the postpartum period. The large variability between patients and the dynamic nature of pregnancy hampers interpretation of smaller studies, but some facts are consistent. Gestational cardiac hypertrophy and a physical shift of the heart contribute to changes in the ECG. There are also electrical changes such as an increased heart rate and lengthening of the QT interval. There is an increased susceptibility to arrhythmias during pregnancy and the postpartum period. Some changes in the ECG are clearly the result of changes in ion channel expression and behaviour, but little is known about the ionic basis for this electrical remodelling. Most information comes from animal models, and implicates changes in the delayed-rectifier channels. However, it is likely that there are additional roles for sodium channels as well as changes in calcium homoeostasis. The changes in the electrical profile of the heart during pregnancy and the postpartum period have clear implications for the safety of pregnant women, but the field remains relatively undeveloped.
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Unravelling the complexities of vascular smooth muscle ion channels: Fine tuning of activity by ancillary subunits. Pharmacol Ther 2017; 178:57-66. [PMID: 28336473 DOI: 10.1016/j.pharmthera.2017.03.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Which ion channel is the most important for regulating vascular tone? Which one is responsible for controlling the resting membrane potential or repolarization? Which channels are recruited by different intracellular signalling pathways or change in certain vascular diseases? Many different ion channels have been identified in the vasculature over the years and claimed as future therapeutic targets. Unfortunately, several of these ion channels are not just found in the vasculature, with many of them also found to have prominent functional roles in different organs of the body, which then leads to off-target effects. As cardiovascular diseases are expected to increase worldwide to epidemic proportions, ion channel research and the hunt for the next major therapeutic target to treat different vascular diseases has never been more important. However, I believe that the question we should now be asking is: which ancillary subunits are involved in regulating specific ion channels in the vasculature and do they have the potential to be new therapeutic targets?
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