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Reeve EH, Barnes JN, Moir ME, Walker AE. Impact of arterial stiffness on cerebrovascular function: a review of evidence from humans and preclincal models. Am J Physiol Heart Circ Physiol 2024; 326:H689-H704. [PMID: 38214904 DOI: 10.1152/ajpheart.00592.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 12/08/2023] [Accepted: 01/08/2024] [Indexed: 01/13/2024]
Abstract
With advancing age, the cerebral vasculature becomes dysfunctional, and this dysfunction is associated with cognitive decline. However, the initiating cause of these age-related cerebrovascular impairments remains incompletely understood. A characteristic feature of the aging vasculature is the increase in stiffness of the large elastic arteries. This increase in arterial stiffness is associated with elevated pulse pressure and blood flow pulsatility in the cerebral vasculature. Evidence from both humans and rodents supports that increases in large elastic artery stiffness are associated with cerebrovascular impairments. These impacts on cerebrovascular function are wide-ranging and include reductions in global and regional cerebral blood flow, cerebral small vessel disease, endothelial cell dysfunction, and impaired perivascular clearance. Furthermore, recent findings suggest that the relationship between arterial stiffness and cerebrovascular function may be influenced by genetics, specifically APOE and NOTCH genotypes. Given the strength of the evidence that age-related increases in arterial stiffness have deleterious impacts on the brain, interventions that target arterial stiffness are needed. The purpose of this review is to summarize the evidence from human and rodent studies, supporting the role of increased arterial stiffness in age-related cerebrovascular impairments.
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Affiliation(s)
- Emily H Reeve
- Department of Human Physiology, University of Oregon, Eugene, Oregon, United States
| | - Jill N Barnes
- Department of Kinesiology University of Wisconsin-Madison, Madison, Wisconsin, United States
| | - M Erin Moir
- Department of Kinesiology University of Wisconsin-Madison, Madison, Wisconsin, United States
| | - Ashley E Walker
- Department of Human Physiology, University of Oregon, Eugene, Oregon, United States
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2
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Wu S, Ootawa T, Sekio R, Smith H, Islam MZ, Nguyen HTT, Uno Y, Shiraishi M, Miyamoto A. Reduced Nitric Oxide Synthase Involvement in Aigamo Duck Basilar Arterial Relaxation. Animals (Basel) 2023; 13:2740. [PMID: 37685004 PMCID: PMC10486467 DOI: 10.3390/ani13172740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Revised: 08/20/2023] [Accepted: 08/26/2023] [Indexed: 09/10/2023] Open
Abstract
The basilar arterial endothelium mediates blood vessel relaxation partly through the release of nitric oxide (NO). Apoptosis of cerebrovascular endothelial cells is linked to a high mortality rate in chickens infected with the highly pathogenic avian influenza virus, but interestingly, ducks exhibit a greater resistance to this virus. In this study, we examined the responsiveness of duck basilar arteries (BAs) to various vasoactive substances, including 5-hydroxytryptamine (5-HT), histamine (His), angiotensin (Ang) II, noradrenaline (NA), acetylcholine (ACh), and avian bradykinin ornithokinin (OK), aiming to characterize the receptor subtypes involved and the role of endothelial NO in vitro. Our findings suggest that arterial contraction is mediated with 5-HT1 and H1 receptors, while relaxation is induced with β3-adrenergic and M3 receptors. Additionally, OK elicited a biphasic response in duck BAs, and Ang II had no effect. Endothelial NO appears to be crucial in relaxation mediated with M3 and OK receptors but not β3-adrenergic receptors in the duck BA. The reduced endothelial NO involvement in the receptor-mediated relaxation response in duck BAs represents a clear difference from the corresponding response reported in chicken BAs. This physiological difference may explain the differences in lethality between ducks and chickens when vascular endothelial cells are infected with the virus.
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Affiliation(s)
- Siyuan Wu
- Department of Basic Veterinary Science, Joint Graduate School of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan
| | - Tomoki Ootawa
- Department of Basic Veterinary Science, Joint Graduate School of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan
- Japan Wildlife Research Center, 3-3-7 Kotobashi, Tokyo 130-8606, Japan
| | - Ryoya Sekio
- Department of Veterinary Pharmacology, Joint Faculty of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan
| | - Henry Smith
- Department of Basic Veterinary Science, Joint Graduate School of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan
- Department of Veterinary Pharmacology, Joint Faculty of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan
| | - Md. Zahorul Islam
- Department of Pharmacology, Faculty of Veterinary Science, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh
| | - Ha Thi Thanh Nguyen
- Department of Veterinary Pharmacology and Toxicology, Faculty of Veterinary Medicine, Vietnam National University of Agriculture, Gia Lam, Hanoi 131000, Vietnam
| | - Yasuhiro Uno
- Department of Basic Veterinary Science, Joint Graduate School of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan
- Department of Veterinary Pharmacology, Joint Faculty of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan
| | - Mitsuya Shiraishi
- Department of Basic Veterinary Science, Joint Graduate School of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan
| | - Atsushi Miyamoto
- Department of Basic Veterinary Science, Joint Graduate School of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan
- Department of Veterinary Pharmacology, Joint Faculty of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan
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Brengle BM, Lin M, Roth RA, Jones KD, Wagenseil JE, Mecham RP, Halabi CM. A new mouse model of elastin haploinsufficiency highlights the importance of elastin to vascular development and blood pressure regulation. Matrix Biol 2023; 117:1-14. [PMID: 36773748 DOI: 10.1016/j.matbio.2023.02.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 01/09/2023] [Accepted: 02/07/2023] [Indexed: 02/11/2023]
Abstract
Supravalvular aortic stenosis (SVAS) is an autosomal dominant disease resulting from elastin (ELN) haploinsufficiency. Individuals with SVAS typically develop a thickened arterial media with an increased number of elastic lamellae and smooth muscle cell (SMC) layers and stenosis superior to the aortic valve. A mouse model of SVAS (Eln+/-) was generated that recapitulates many aspects of the human disease, including increased medial SMC layers and elastic lamellae, large artery stiffness, and hypertension. The vascular changes in these mice were thought to be responsible for the hypertension phenotype. However, a renin gene (Ren) duplication in the original 129/Sv genetic background and carried through numerous strain backcrosses raised the possibility of renin-mediated effects on blood pressure. To exclude excess renin activity as a disease modifier, we utilized the Cre-LoxP system to rederive Eln hemizygous mice on a pure C57BL/6 background (Sox2-Cre;Elnf/f). Here we show that Sox2-Cre;Eln+/f mice, with a single Ren1 gene and normal renin levels, phenocopy the original global knockout line. Characteristic traits include an increased number of elastic lamellae and SMC layers, stiff elastic arteries, and systolic hypertension with widened pulse pressure. Importantly, small resistance arteries of Sox2-Cre;Eln+/f mice exhibit a significant change in endothelial cell function and hypercontractility to angiotensin II, findings that point to pathway-specific alterations in resistance arteries that contribute to the hypertensive phenotype. These data confirm that the cardiovascular changes, particularly systolic hypertension, seen in Eln+/- mice are due to Eln hemizygosity rather than Ren duplication.
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Affiliation(s)
- Bridget M Brengle
- Department of Pediatrics, Division of Nephrology, Washington University School of Medicine, St. Louis, MO, USA
| | - Michelle Lin
- Department of Pediatrics, Division of Nephrology, Washington University School of Medicine, St. Louis, MO, USA
| | - Robyn A Roth
- Department of Pediatrics, Division of Nephrology, Washington University School of Medicine, St. Louis, MO, USA
| | - Kara D Jones
- Department of Pediatrics, Division of Nephrology, Washington University School of Medicine, St. Louis, MO, USA
| | - Jessica E Wagenseil
- Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, MO, USA
| | - Robert P Mecham
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO, U.S.A
| | - Carmen M Halabi
- Department of Pediatrics, Division of Nephrology, Washington University School of Medicine, St. Louis, MO, USA.
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Walker AE, Cole JA, Krishna Kumaran S, Kato JI, Zhuang X, Wolf JR, Henson GD, McCully BH. INFLUENCE OF OBESITY ON VASCULAR DYSFUNCTION AFTER TRAUMATIC HEMORRHAGE. Shock 2023; 59:318-325. [PMID: 36731028 DOI: 10.1097/shk.0000000000001991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
ABSTRACT Background: Obesity increases the risk for morbidity and mortality after trauma. These complications are associated with profound vascular damage. Traumatic hemorrhage acutely attenuates vascular responsiveness, but the impact of obesity on this dysfunction is not known. The local inflammatory response in vascular cells is also unknown. We hypothesized that obesity potentiates trauma-induced vascular inflammation and dysfunction. Methods: Male Sprague-Dawley rats (~250 g) were fed normal chow (NC; 13.5% kcal fat, n = 20) or high-fat (HF; 60% kcal fat, n = 20) diets for 6 to 8 weeks. Under anesthesia, hemorrhage was induced by a mesenteric artery laceration, a Grade V splenic injury, and hypotension (MAP = 30-40 mm Hg) for 30 minutes. Vascular responsiveness was assessed ex vivo in isolated mesenteric arteries prehemorrhage and posthemorrhage. Gene expression for IL-1β, and IL-6, prooxidant nicotinamide adenine dinucleotide phosphate oxidase 2 (NOX2), and α-adrenergic receptor were assessed in carotid artery endothelial cells (ECs) and non-ECs (media + adventitia). Results: In NC rats, hemorrhage attenuated norepinephrine-induced vasoconstriction and endothelium-dependent vasodilation to acetylcholine. In HF rats, baseline norepinephrine-induced vasoconstriction was attenuated compared with NC, but vasoconstriction and endothelium-dependent vasodilation did not change prehemorrhage to posthemorrhage. Hemorrhage led to elevated IL-1β gene expression in ECs and elevated IL1β, IL-6, NOX2, and α-adrenergic receptor gene expression in the media + adventitia compared with sham. HF rats had greater EC IL-1 β and NOX2 gene expression compared with NC rats. The hemorrhage-induced elevation of IL-1β in the media + adventitia was greatest in HF rats. Conclusion: Traumatic hemorrhage attenuates vascular responsiveness and induces vascular inflammation. The attenuated vascular responsiveness after hemorrhage is absent in obese rats, while the elevated vascular inflammation persists. A HF diet amplifies the arterial inflammation after hemorrhage. Altered vascular responsiveness and vascular inflammation may contribute to worse outcomes in obese trauma patients.
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Affiliation(s)
- Ashley E Walker
- Department of Human Physiology, University of Oregon, Eugene, OR
| | - Jazmin A Cole
- Department of Human Physiology, University of Oregon, Eugene, OR
| | | | - Jonathan I Kato
- Department of Human Physiology, University of Oregon, Eugene, OR
| | - Xinhao Zhuang
- Department of Human Physiology, University of Oregon, Eugene, OR
| | - Julia R Wolf
- Department of Human Physiology, University of Oregon, Eugene, OR
| | - Grant D Henson
- Department of Human Physiology, University of Oregon, Eugene, OR
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Reeve EH, Kronquist EK, Wolf JR, Lee B, Khurana A, Pham H, Cullen AE, Peterson JA, Meza A, Colton Bramwell R, Villasana L, Machin DR, Henson GD, Walker AE. Pyridoxamine treatment ameliorates large artery stiffening and cerebral artery endothelial dysfunction in old mice. J Cereb Blood Flow Metab 2023; 43:281-295. [PMID: 36189840 PMCID: PMC9903220 DOI: 10.1177/0271678x221130124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Age-related increases in large artery stiffness are associated with cerebrovascular dysfunction and cognitive impairment. Pyridoxamine treatment prevents large artery stiffening with advancing age, but the effects of pyridoxamine treatment on the cerebral vasculature or cognition is unknown. The purpose of this study was to investigate the effects of pyridoxamine on blood pressure, large artery stiffness, cerebral artery function, and cognitive function in old mice. Old male C57BL/6 mice consumed either pyridoxamine (2 g/L) or vehicle control in drinking water for ∼7.5 months and were compared with young male C57BL/6 mice. From pre- to post-treatment, systolic blood pressure increased in old control mice, but was maintained in pyridoxamine treated mice. Large artery stiffness decreased in pyridoxamine-treated mice but was unaffected in control mice. Pyridoxamine-treated mice had greater cerebral artery endothelium-dependent dilation compared with old control mice, and not different from young mice. Old control mice had impaired cognitive function; however, pyridoxamine only partially preserved cognitive function in old mice. In summary, pyridoxamine treatment in old mice prevented age-related increases in blood pressure, reduced large artery stiffness, preserved cerebral artery endothelial function, and partially preserved cognitive function. Taken together, these results suggest that pyridoxamine treatment may limit vascular aging.
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Affiliation(s)
- Emily H Reeve
- Department of Human Physiology, 3265, University of Oregon, Eugene, OR, USA
| | - Elise K Kronquist
- Department of Human Physiology, 3265, University of Oregon, Eugene, OR, USA
| | - Julia R Wolf
- Department of Human Physiology, 3265, University of Oregon, Eugene, OR, USA
| | - Byron Lee
- Department of Human Physiology, 3265, University of Oregon, Eugene, OR, USA
| | - Aleena Khurana
- Department of Human Physiology, 3265, University of Oregon, Eugene, OR, USA
| | - Hanson Pham
- Department of Human Physiology, 3265, University of Oregon, Eugene, OR, USA
| | - Abigail E Cullen
- Department of Human Physiology, 3265, University of Oregon, Eugene, OR, USA
| | - Jessica A Peterson
- Department of Human Physiology, 3265, University of Oregon, Eugene, OR, USA
| | - Antonio Meza
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA
| | - R Colton Bramwell
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA
| | | | - Daniel R Machin
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA
- Department of Nutrition and Integrative Physiology, 7823, Florida State University, Tallahassee, FL, USA
| | - Grant D Henson
- Department of Human Physiology, 3265, University of Oregon, Eugene, OR, USA
| | - Ashley E Walker
- Department of Human Physiology, 3265, University of Oregon, Eugene, OR, USA
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA
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Pierce GL, Coutinho TA, DuBose LE, Donato AJ. Is It Good to Have a Stiff Aorta with Aging? Causes and Consequences. Physiology (Bethesda) 2022; 37:154-173. [PMID: 34779281 PMCID: PMC8977146 DOI: 10.1152/physiol.00035.2021] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 10/28/2021] [Accepted: 11/08/2021] [Indexed: 01/09/2023] Open
Abstract
Aortic stiffness increases with advancing age, more than doubling during the human life span, and is a robust predictor of cardiovascular disease (CVD) clinical events independent of traditional risk factors. The aorta increases in diameter and length to accommodate growing body size and cardiac output in youth, but in middle and older age the aorta continues to remodel to a larger diameter, thinning the pool of permanent elastin fibers, increasing intramural wall stress and resulting in the transfer of load bearing onto stiffer collagen fibers. Whereas aortic stiffening in early middle age may be a compensatory mechanism to normalize intramural wall stress and therefore theoretically "good" early in the life span, the negative clinical consequences of accelerated aortic stiffening beyond middle age far outweigh any earlier physiological benefit. Indeed, aortic stiffness and the loss of the "windkessel effect" with advancing age result in elevated pulsatile pressure and flow in downstream microvasculature that is associated with subclinical damage to high-flow, low-resistance organs such as brain, kidney, retina, and heart. The mechanisms of aortic stiffness include alterations in extracellular matrix proteins (collagen deposition, elastin fragmentation), increased arterial tone (oxidative stress and inflammation-related reduced vasodilators and augmented vasoconstrictors; enhanced sympathetic activity), arterial calcification, vascular smooth muscle cell stiffness, and extracellular matrix glycosaminoglycans. Given the rapidly aging population of the United States, aortic stiffening will likely contribute to substantial CVD burden over the next 2-3 decades unless new therapeutic targets and interventions are identified to prevent the potential avalanche of clinical sequelae related to age-related aortic stiffness.
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Affiliation(s)
- Gary L Pierce
- Department of Health and Human Physiology, University of Iowa, Iowa City, Iowa
- Department of Internal Medicine, University of Iowa, Iowa City, Iowa
- Abboud Cardiovascular Research Center, University of Iowa, Iowa City, Iowa
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa
| | - Thais A Coutinho
- Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada
- Divisions of Cardiology and Cardiac Prevention and Rehabilitation, University of Ottawa Heart Institute, Ottawa, Ontario, Canada
| | - Lyndsey E DuBose
- Division of Geriatrics, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Anthony J Donato
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah
- Department of Biochemistry, University of Utah, Salt Lake City, Utah
- Geriatric Research Education and Clinical Center, VA Salt Lake City, Salt Lake City, Utah
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Lin M, Roth RA, Kozel BA, Mecham RP, Halabi CM. Loss of Angiotensin II Type 2 Receptor Improves Blood Pressure in Elastin Insufficiency. Front Cardiovasc Med 2021; 8:782138. [PMID: 34790711 PMCID: PMC8591102 DOI: 10.3389/fcvm.2021.782138] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 10/11/2021] [Indexed: 11/13/2022] Open
Abstract
There is ample evidence supporting a role for angiotensin II type 2 receptor (AT2R) in counterbalancing the effects of angiotensin II (ang II) through the angiotensin II type 1 receptor by promoting vasodilation and having anti-inflammatory effects. Elastin insufficiency in both humans and mice results in large artery stiffness and systolic hypertension. Unexpectedly, mesenteric arteries from elastin insufficient (Eln+/−) mice were shown to have significant vasoconstriction to AT2R agonism in vitro suggesting that AT2R may have vasoconstrictor effects in elastin insufficiency. Given the potential promise for the use of AT2R agonists clinically, the goal of this study was to determine whether AT2R has vasoconstrictive effects in elastin insufficiency in vivo. To avoid off-target effects of agonists and antagonists, mice lacking AT2R (Agtr2−/Y) were bred to Eln+/− mice and cardiovascular parameters were assessed in wild-type (WT), Agtr2−/Y, Eln+/−, and Agtr2−/Y;Eln+/− littermates. As previously published, Agtr2−/Y mice were normotensive at baseline and had no large artery stiffness, while Eln+/− mice exhibited systolic hypertension and large artery stiffness. Loss of AT2R in Eln+/− mice did not affect large artery stiffness or arterial structure but resulted in significant reduction of both systolic and diastolic blood pressure. These data support a potential vasocontractile role for AT2R in elastin insufficiency. Careful consideration and investigation are necessary to determine the patient population that might benefit from the use of AT2R agonists.
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Affiliation(s)
- Michelle Lin
- Division of Nephrology, Department of Pediatrics, Washington University School of Medicine, Saint Louis, MO, United States
| | - Robyn A Roth
- Department of Cell Biology and Physiology, Washington University School of Medicine, Saint Louis, MO, United States
| | - Beth A Kozel
- National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, United States
| | - Robert P Mecham
- Department of Cell Biology and Physiology, Washington University School of Medicine, Saint Louis, MO, United States
| | - Carmen M Halabi
- Division of Nephrology, Department of Pediatrics, Washington University School of Medicine, Saint Louis, MO, United States
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Troia A, Knutsen RH, Halabi CM, Malide D, Yu ZX, Wardlaw-Pickett A, Kronquist EK, Tsang KM, Kovacs A, Mecham RP, Kozel BA. Inhibition of NOX1 Mitigates Blood Pressure Increases in Elastin Insufficiency. Function (Oxf) 2021; 2:zqab015. [PMID: 34223172 PMCID: PMC8248879 DOI: 10.1093/function/zqab015] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2021] [Revised: 03/06/2021] [Accepted: 03/09/2021] [Indexed: 02/07/2023]
Abstract
Elastin (ELN) insufficiency leads to the cardiovascular hallmarks of the contiguous gene deletion disorder, Williams-Beuren syndrome, including hypertension and vascular stiffness. Previous studies showed that Williams-Beuren syndrome deletions, which extended to include the NCF1 gene, were associated with lower blood pressure (BP) and reduced vascular stiffness. NCF1 encodes for p47phox, the regulatory component of the NOX1 NADPH oxidase complex that generates reactive oxygen species (ROS) in the vascular wall. Dihydroethidium and 8-hydroxyguanosine staining of mouse aortas confirmed that Eln heterozygotes (Eln+/- ) had greater ROS levels than the wild-types (Eln+/+ ), a finding that was negated in vessels cultured without hemodynamic stressors. To analyze the Nox effect on ELN insufficiency, we used both genetic and chemical manipulations. Both Ncf1 haploinsufficiency (Ncf1+/- ) and Nox1 insufficiency (Nox1-/y ) decreased oxidative stress and systolic BP in Eln+/- without modifying vascular structure. Chronic treatment with apocynin, a p47phox inhibitor, lowered systolic BP in Eln+/- , but had no impact on Eln+/+ controls. In vivo dosing with phenylephrine (PE) produced an augmented BP response in Eln+/- relative to Eln+/+ , and genetic modifications or drug-based interventions that lower Nox1 expression reduced the hypercontractile response to PE in Eln+/- mice to Eln+/+ levels. These results indicate that the mechanical and structural differences caused by ELN insufficiency leading to oscillatory flow can perpetuate oxidative stress conditions, which are linked to hypertension, and that by lowering the Nox1-mediated capacity for vascular ROS production, BP differences can be normalized.
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Affiliation(s)
- Angela Troia
- National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Russell H Knutsen
- National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Carmen M Halabi
- Department of Pediatrics, Washington University School of Medicine, St. Louis, MO, USA
| | - Daniela Malide
- National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Zu Xi Yu
- National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Amanda Wardlaw-Pickett
- National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Elise K Kronquist
- National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Kit Man Tsang
- National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Attila Kovacs
- Department of Internal Medicine, Cardiovascular Division, Washington University School of Medicine, St. Louis, MO, USA
| | - Robert P Mecham
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Beth A Kozel
- National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA,Address correspondence to B.A.K. (e-mail: )
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Abstract
There are no effective treatments available to halt or reverse the progression of age-related cognitive decline and Alzheimer's disease. Thus, there is an urgent need to understand the underlying mechanisms of disease etiology and progression to identify novel therapeutic targets. Age-related changes to the vasculature, particularly increases in stiffness of the large elastic arteries, are now recognized as important contributors to brain aging. There is a growing body of evidence for an association between greater large artery stiffness and cognitive impairment among both healthy older adults and patients with Alzheimer's disease. However, studies in humans are limited to only correlative evidence, whereas animal models allow researchers to explore the causative mechanisms linking arterial stiffness to neurocognitive dysfunction and disease. Recently, several rodent models of direct modulation of large artery stiffness and the consequent effects on the brain have been reported. Common outcomes among these models have emerged, including evidence that greater large artery stiffness causes cerebrovascular dysfunction associated with increased oxidative stress and inflammatory signaling. The purpose of this mini-review is to highlight the recent findings associating large artery stiffness with deleterious brain outcomes, with a specific focus on causative evidence obtained from animal models. We will also discuss the gaps in knowledge that remain in our understanding of how large artery stiffness affects brain function and disease outcomes.
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Affiliation(s)
- Nick R Winder
- Department of Human Physiology, University of Oregon, Eugene, Oregon
| | - Emily H Reeve
- Department of Human Physiology, University of Oregon, Eugene, Oregon
| | - Ashley E Walker
- Department of Human Physiology, University of Oregon, Eugene, Oregon
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10
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Noureddine FY, Altara R, Fan F, Yabluchanskiy A, Booz GW, Zouein FA. Impact of the Renin-Angiotensin System on the Endothelium in Vascular Dementia: Unresolved Issues and Future Perspectives. Int J Mol Sci 2020; 21:E4268. [PMID: 32560034 PMCID: PMC7349348 DOI: 10.3390/ijms21124268] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2020] [Revised: 06/12/2020] [Accepted: 06/14/2020] [Indexed: 12/11/2022] Open
Abstract
The effects of the renin-angiotensin system (RAS) surpass the renal and cardiovascular systems to encompass other body tissues and organs, including the brain. Angiotensin II (Ang II), the most potent mediator of RAS in the brain, contributes to vascular dementia via different mechanisms, including neuronal homeostasis disruption, vascular remodeling, and endothelial dysfunction caused by increased inflammation and oxidative stress. Other RAS components of emerging significance at the level of the blood-brain barrier include angiotensin-converting enzyme 2 (ACE2), Ang(1-7), and the AT2, Mas, and AT4 receptors. The various angiotensin hormones perform complex actions on brain endothelial cells and pericytes through specific receptors that have either detrimental or beneficial actions. Increasing evidence indicates that the ACE2/Ang(1-7)/Mas axis constitutes a protective arm of RAS on the blood-brain barrier. This review provides an update of studies assessing the different effects of angiotensins on cerebral endothelial cells. The involved signaling pathways are presented and help highlight the potential pharmacological targets for the management of cognitive and behavioral dysfunctions associated with vascular dementia.
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Affiliation(s)
- Fatima Y. Noureddine
- Department of Pharmacology and Toxicology, Faculty of Medicine, American University of Beirut, Beirut 1107 2020, Lebanon;
| | - Raffaele Altara
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, and KG Jebsen Center for Cardiac Research, 0424 Oslo, Norway;
| | - Fan Fan
- Department of Pharmacology and Toxicology, School of Medicine, The University of Mississippi Medical Center, Jackson, MS 39216, USA; (F.F.); (G.W.B.)
| | - Andriy Yabluchanskiy
- Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA;
| | - George W. Booz
- Department of Pharmacology and Toxicology, School of Medicine, The University of Mississippi Medical Center, Jackson, MS 39216, USA; (F.F.); (G.W.B.)
| | - Fouad A. Zouein
- Department of Pharmacology and Toxicology, Faculty of Medicine, American University of Beirut, Beirut 1107 2020, Lebanon;
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11
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Abstract
Cerebral small vessel disease (SVD) is characterized by changes in the pial and parenchymal microcirculations. SVD produces reductions in cerebral blood flow and impaired blood-brain barrier function, which are leading contributors to age-related reductions in brain health. End-organ effects are diverse, resulting in both cognitive and noncognitive deficits. Underlying phenotypes and mechanisms are multifactorial, with no specific treatments at this time. Despite consequences that are already considerable, the impact of SVD is predicted to increase substantially with the growing aging population. In the face of this health challenge, the basic biology, pathogenesis, and determinants of SVD are poorly defined. This review summarizes recent progress and concepts in this area, highlighting key findings and some major unanswered questions. We focus on phenotypes and mechanisms that underlie microvascular aging, the greatest risk factor for cerebrovascular disease and its subsequent effects.
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Affiliation(s)
- T Michael De Silva
- Department of Physiology, Anatomy and Microbiology, School of Life Sciences, La Trobe University, Melbourne Campus, Bundoora, Victoria 3086, Australia;
| | - Frank M Faraci
- Departments of Internal Medicine, Neuroscience, and Pharmacology, Francois M. Abboud Cardiovascular Center, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242, USA;
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