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Xue Y, Liu N, Zhang M, Ren X, Tang J, Fu J. Concomitant enlargement of perivascular spaces and decrease in glymphatic transport in an animal model of cerebral small vessel disease. Brain Res Bull 2020; 161:78-83. [PMID: 32353396 DOI: 10.1016/j.brainresbull.2020.04.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Revised: 03/04/2020] [Accepted: 04/09/2020] [Indexed: 12/18/2022]
Abstract
OBJECTIVES To observe glymphatic transport and evaluate enlarged perivascular spaces (PVSs) in spontaneously hypertensive rats (SHRs). METHODS SHRs were used as an animal model of cerebral small vessel disease, and Wistar Kyoto (WKY) rats were used as the control group. Histopathology was used to evaluate the enlargement of PVSs. A fluorescent tracer was infused into the cisterna magna of rats, and the proportion of the brain parenchyma area exposed to the fluorescent tracer was later quantified to evaluate the influx and efflux function of the glymphatic system. The global and polarized expression of aquaporin protein 4 (AQP4) was analyzed by immunofluorescence. RESULTS Compared with WKY rats, SHRs exhibited obviously enlarged PVSs and significantly decreased influx and efflux function of the glymphatic system. The results showed a significant decrease in AQP4 polarity in SHRs, but a difference in global AQP4 expression was not observed between SHRs and WKY rats. CONCLUSIONS Impaired glymphatic transport may be involved in the pathogenesis of arteriolosclerotic cerebral small vessel disease, and enlarged PVSs may be a manifestation of the impaired glymphatic system.
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Affiliation(s)
- Yang Xue
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai, China.
| | - Na Liu
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai, China.
| | - Miaoyi Zhang
- Department of Neurology, North of Huashan Hospital, Fudan University, Shanghai, China.
| | - Xue Ren
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai, China.
| | - Jie Tang
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai, China.
| | - Jianhui Fu
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai, China.
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2
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Altered Cerebral Blood Flow and Potential Neuroprotective Effect of Human Relaxin-2 (Serelaxin) During Hypoxia or Severe Hypovolemia in a Sheep Model. Int J Mol Sci 2020; 21:ijms21051632. [PMID: 32120997 PMCID: PMC7084399 DOI: 10.3390/ijms21051632] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 02/21/2020] [Accepted: 02/25/2020] [Indexed: 12/15/2022] Open
Abstract
Specific neuroprotective strategies to minimize cerebral damage caused by severe hypoxia or hypovolemia are lacking. Based on previous studies showing that relaxin-2/serelaxin increases cortical cerebral blood flow, we postulated that serelaxin might provide a neuroprotective effect. Therefore, we tested serelaxin in two emergency models: hypoxia was induced via inhalation of 5% oxygen and 95% nitrogen for 12 min; thereafter, the animals were reoxygenated. Hypovolemia was induced and maintained for 20 min by removal of 50% of the total blood volume; thereafter, the animals were retransfused. In each damage model, the serelaxin group received an intravenous injection of 30 µg/kg of serelaxin in saline, while control animals received saline only. Blood gases, shock index values, heart frequency, blood pressure, and renal blood flow showed almost no significant differences between control and treatment groups in both settings. However, serelaxin significantly blunted the increase of lactate during hypovolemia. Serelaxin treatment resulted in significantly elevated cortical cerebral blood flow (CBF) in both damage models, compared with the respective control groups. Measurements of the neuroproteins S100B and neuron-specific enolase in cerebrospinal fluid revealed a neuroprotective effect of serelaxin treatment in both hypoxic and hypovolemic animals, whereas in control animals, neuroproteins increased during the experiment. Western blotting showed the expression of relaxin receptors and indicated region-specific differences in relaxin receptor-mediated signaling in cortical and subcortical brain arterioles, respectively. Our findings support the hypothesis that serelaxin is a potential neuroprotectant during hypoxia and hypovolemia. Due to its preferential improvement of cortical CBF, serelaxin might reduce cognitive impairments associated with these emergencies.
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3
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Leo CH, Ng HH, Marshall SA, Jelinic M, Rupasinghe T, Qin C, Roessner U, Ritchie RH, Tare M, Parry LJ. Relaxin reduces endothelium-derived vasoconstriction in hypertension: Revealing new therapeutic insights. Br J Pharmacol 2019; 177:217-233. [PMID: 31479151 DOI: 10.1111/bph.14858] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 08/21/2019] [Accepted: 08/26/2019] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND AND PURPOSE Endothelium-derived vasoconstriction is a hallmark of vascular dysfunction in hypertension. In some cases, an overproduction of endothelium-derived prostacyclin (PGI2 ) can cause contraction rather than relaxation. Relaxin is well known for its vasoprotective actions, but the possibility that this peptide could also reverse endothelium-derived vasoconstriction has never been investigated. We tested the hypothesis that short-term relaxin treatment mitigates endothelium-derived vasoconstriction in spontaneously hypertensive rats (SHR). EXPERIMENTAL APPROACH Male Wistar Kyoto rats (WKY) and SHR were subcutaneously infused with either vehicle (20 mmol·L-1 sodium acetate) or relaxin (13.3 μg·kg-1 ·hr-1 ) using osmotic minipumps for 3 days. Vascular reactivity to the endothelium-dependent agonist ACh was assessed in vitro by wire myography. Quantitative PCR and LC-MS were used to identify changes in gene expression of prostanoid pathways and PG production, respectively. KEY RESULTS Relaxin treatment ameliorated hypertension-induced endothelial dysfunction by increasing NO-dependent relaxation and reducing endothelium-dependent contraction. Notably, short-term relaxin treatment up-regulated mesenteric PGI2 receptor (IP) expression, permitting PGI2 -IP-mediated vasorelaxation. In the aorta, reversal of contraction was accompanied by suppression of the hypertension-induced increase in prostanoid-producing enzymes and reduction in PGI2 -evoked contractions. CONCLUSIONS AND IMPLICATIONS Relaxin has region-dependent vasoprotective actions in hypertension. Specifically, relaxin has distinct effects on endothelium-derived contracting factors and their associated vasoconstrictor pathways in mesenteric arteries and the aorta. Taken together, these observations reveal the potential of relaxin as a new therapeutic agent for vascular disorders that are associated with endothelium-derived vasoconstriction including hypertension.
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Affiliation(s)
- Chen Huei Leo
- School of Biosciences, The University of Melbourne, Parkville, VIC, Australia
| | - Hooi Hooi Ng
- School of Biosciences, The University of Melbourne, Parkville, VIC, Australia.,Heart Failure Pharmacology, Baker Heart & Diabetes Institute, Melbourne, VIC, Australia
| | - Sarah A Marshall
- School of Biosciences, The University of Melbourne, Parkville, VIC, Australia
| | - Maria Jelinic
- School of Biosciences, The University of Melbourne, Parkville, VIC, Australia
| | - Thusitha Rupasinghe
- Metabolomics Australia, School of Biosciences, The University of Melbourne, Parkville, VIC, Australia
| | - Chengxue Qin
- Heart Failure Pharmacology, Baker Heart & Diabetes Institute, Melbourne, VIC, Australia.,Department of Pharmacology & Therapeutics, The University of Melbourne, Parkville, VIC, Australia
| | - Ute Roessner
- School of Biosciences, The University of Melbourne, Parkville, VIC, Australia.,Metabolomics Australia, School of Biosciences, The University of Melbourne, Parkville, VIC, Australia
| | - Rebecca H Ritchie
- Heart Failure Pharmacology, Baker Heart & Diabetes Institute, Melbourne, VIC, Australia.,Department of Diabetes, Monash University, Clayton, VIC, Australia
| | - Marianne Tare
- Monash Rural Health, Monash University, Churchill, VIC, Australia.,Department of Physiology, Monash University, Clayton, VIC, Australia
| | - Laura J Parry
- School of Biosciences, The University of Melbourne, Parkville, VIC, Australia
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4
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Cao Y, Li Z, Ma L, Yang N, Guo X. Isoflurane-Induced Postoperative Neurovascular and Cognitive Dysfunction Is Associated with VEGF Overexpression in Aged Rats. J Mol Neurosci 2019; 69:215-223. [PMID: 31250275 DOI: 10.1007/s12031-019-01350-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 05/29/2019] [Indexed: 12/18/2022]
Abstract
Postoperative cognitive dysfunction (POCD) is a common complication in older adults; however, its aetiology remains unclear. Although vascular endothelial growth factor (VEGF) is associated with blood-brain barrier (BBB) disorders and neurological disease, its role in POCD is unknown. Here, we investigated the effect of brain VEGF inhibition on isoflurane-induced cognitive impairment in an aged rat model of POCD. VEGF protein expression was increased in the hippocampus after isoflurane exposure, suggesting that inhalation anaesthesia induces hippocampal VEGF protein overexpression in aged rats. Pretreatment with 2 mg/kg RB-222, an anti-VEGF neutralizing antibody, may partially abolish the degradation of occludin protein in cerebral capillaries, thereby maintaining the ultrastructural and functional integrity of the hippocampal BBB. Inhibition of VEGF also significantly attenuated the isoflurane-induced cognitive deficits in the Morris water maze task. Together, our findings show, for the first time, that elevated expression of brain VEGF after isoflurane exposure contributes to POCD in aged rats. Therefore, therapeutic strategies involving VEGF should take into consideration its role in the pathogenesis of POCD.
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Affiliation(s)
- Yiyun Cao
- Department of Anesthesiology, Shanghai Sixth People's Hospital East Affiliated to Shanghai University of Medicine & Health Sciences, Shanghai, 200233, China.,Department of Anesthesiology, Peking University Third Hospital, Beijing, 100191, China
| | - Zhengqian Li
- Department of Anesthesiology, Peking University Third Hospital, Beijing, 100191, China
| | - Lijun Ma
- Department of Medical Imaging, North Minzu University, Yinchuan, 750021, Ningxia, China
| | - Ning Yang
- Department of Anesthesiology, Peking University Third Hospital, Beijing, 100191, China
| | - Xiangyang Guo
- Department of Anesthesiology, Peking University Third Hospital, Beijing, 100191, China.
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5
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Conrad KP, Phillips EG, Jiron J, Bailes J, Dhar B, Diao Y, Aguirre JI, Yarrow JF. Potential therapeutic use of relaxin in accelerating closure of cranial bone defects in mice. Physiol Rep 2019; 7:e14106. [PMID: 31155858 PMCID: PMC6545299 DOI: 10.14814/phy2.14106] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 05/02/2019] [Accepted: 05/02/2019] [Indexed: 01/24/2023] Open
Abstract
Bone fractures are associated with considerable morbidity and increased mortality. A major limitation to healing is lack of bone blood flow, which is impaired by physical disruption of intraskeletal and/or periosteal vasculature by the fracture. Thus, pharmacological interventions are needed to improve osseous blood flow, thereby accelerating bone fracture closure. Relaxin is secreted by the ovary and circulates in rodents and humans during pregnancy. Because relaxin might benefit bone fracture healing by stimulating angiogenesis, vasculogenesis (and potentially osteogenesis) through mobilization and activation of bone marrow progenitor cells, and by increasing blood flow via vasodilation, we investigated whether relaxin administration would accelerate closure of a calvarial defect in mice. Whether administered systemically by osmotic pump or locally by collagen scaffolds for ~2 week period after lesioning, relaxin did not accelerate bone healing. Despite implementing relaxin doses that reached plasma concentrations spanning the physiological to supraphysiological range, testing the closure of two different sizes of calvarial lesions, allowing for different intervals of time from instigation of cranial lesion to euthanasia, and investigating mice of different ages, we did not observe a significant benefit of relaxin in bone lesion healing. Nor did we observe stimulation of blood vessel formation in the bone lesion by the hormone. An incidental finding was that relaxin appeared to enhance trabecular bone growth in an uninjured control bone (femur). Although the results of this study were not supportive of a therapeutic benefit for relaxin on calvarial defect closure, future investigation is needed employing different animal species and experimental models of bone fracture.
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Affiliation(s)
- Kirk P. Conrad
- Department of Physiology and Functional Genomics, Obstetrics and GynecologyUniversity of Florida College of MedicineGainesvilleFlorida
- D.H. Barron Reproductive and Perinatal Biology Research ProgramUniversity of FloridaGainesvilleFlorida
| | - Ean G. Phillips
- Research Service Malcom Randall VA Medical CenterNorth Florida/South GeorgiaVeterans Health SystemGainesvilleFlorida
| | - Jessica Jiron
- Department of Physiological SciencesCollege of Veterinary MedicineUniversity of FloridaGainesvilleFlorida
| | - Julie Bailes
- Department of Physiology and Functional Genomics, Obstetrics and GynecologyUniversity of Florida College of MedicineGainesvilleFlorida
| | - Biswadeep Dhar
- Department of Physiology and Functional Genomics, Obstetrics and GynecologyUniversity of Florida College of MedicineGainesvilleFlorida
| | - YanPeng Diao
- Division of Nephrology, Hypertension & Renal TransplantationDepartment of MedicineUniversity of Florida College of MedicineGainesvilleFlorida
| | - Jose Ignacio Aguirre
- Department of Physiological SciencesCollege of Veterinary MedicineUniversity of FloridaGainesvilleFlorida
| | - Joshua F. Yarrow
- Research Service Malcom Randall VA Medical CenterNorth Florida/South GeorgiaVeterans Health SystemGainesvilleFlorida
- Brain Rehabilitation Research CenterMalcom Randall VA Medical CenterNorth Florida/South Georgia Veterans Health SystemGainesvilleFlorida
- Division of Endocrinology, Diabetes, and MetabolismUniversity of Florida College of MedicineGainesvilleFlorida
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6
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Valkovic AL, Bathgate RA, Samuel CS, Kocan M. Understanding relaxin signalling at the cellular level. Mol Cell Endocrinol 2019; 487:24-33. [PMID: 30592984 DOI: 10.1016/j.mce.2018.12.017] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 12/19/2018] [Accepted: 12/22/2018] [Indexed: 02/07/2023]
Abstract
The peptide hormone relaxin mediates many biological actions including anti-fibrotic, vasodilatory, angiogenic, anti-inflammatory, anti-apoptotic, and organ protective effects across a range of tissues. At the cellular level, relaxin binds to the G protein-coupled receptor relaxin family peptide receptor 1 (RXFP1) to activate a variety of downstream signal transduction pathways. This signalling cascade is complex and also varies in diverse cellular backgrounds. Moreover, RXFP1 signalling shows crosstalk with other receptors to mediate some of its physiological functions. This review summarises known signalling pathways induced by acute versus chronic treatment with relaxin across a range of cell types, it describes RXFP1 crosstalk with other receptors, signalling pathways activated by other ligands targeting RXFP1, and it also outlines physiological relevance of RXFP1 signalling outputs. Comprehensive understanding of the mechanism of relaxin actions in fibrosis, vasodilation, as well as organ protection, will further support relaxin's clinical potential.
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Affiliation(s)
- Adam L Valkovic
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Ross Ad Bathgate
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, 3010, Australia; Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, 3052, Australia.
| | - Chrishan S Samuel
- Cardiovascular Disease Program, Biomedicine Discovery Institute and Department of Pharmacology, Monash University, Clayton, Victoria, 3800, Australia
| | - Martina Kocan
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, 3010, Australia.
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Chan SL, Nelson MT, Cipolla MJ. Transient receptor potential vanilloid-4 channels are involved in diminished myogenic tone in brain parenchymal arterioles in response to chronic hypoperfusion in mice. Acta Physiol (Oxf) 2019; 225:e13181. [PMID: 30153398 DOI: 10.1111/apha.13181] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Revised: 08/22/2018] [Accepted: 08/24/2018] [Indexed: 12/11/2022]
Abstract
AIM Adaptive responses of brain parenchymal arterioles (PAs), a target for cerebral small vessel disease, to chronic cerebral hypoperfusion are largely unknown. Previous evidence suggested that transient receptor potential vanilloid 4 channels may be involved in the regulation of cerebrovascular tone. Therefore, we investigated the role of TRPV4 in adaptations of PAs in a mouse model of chronic hypoperfusion. METHODS TRPV4 knockout (-/- ) and wild-type (WT) mice were subjected to unilateral common carotid artery occlusion (UCCAo) for 28 days. Function and structure of PAs ipsilateral to UCCAo were studied isolated and pressurized in an arteriograph. RESULTS Basal tone of PAs was similar between WT and TRPV4-/- mice (22 ± 3 vs 23 ± 5%). After UCCAo, active inner diameters of PAs from WT mice were larger than control (41 ± 2 vs 26 ± 5 μm, P < 0.05) that was due to decreased tone (8 ± 2 vs 23 ± 5%, P < 0.05), increased passive inner diameters (46 ± 3 vs 34 ± 2 μm, P < 0.05), and decreased wall-to-lumen ratio (0.104 ± 0.01 vs 0.137 ± 0.01, P < 0.05). However, UCCAo did not affect vasodilation to a small- and intermediate-conductance calcium-activated potassium channel agonist NS309, the nitric oxide (NO) donor sodium nitroprusside, or constriction to a NO synthase inhibitor L-NNA. Wall thickness and distensibility in PAs from WT mice were unaffected. In TRPV4-/- mice, UCCAo had no effect on active inner diameters or tone and only increased passive inner diameters (53 ± 2 vs 43 ± 3 μm, P < 0.05). CONCLUSION Adaptive response of PAs to chronic cerebral hypoperfusion includes myogenic tone reduction and outward remodelling. TRPV4 channels were involved in tone reduction but not outward remodelling in response to UCCAo.
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Affiliation(s)
- Siu-Lung Chan
- Department of Neurological Sciences; University of Vermont College of Medicine; Burlington Vermont
| | - Mark T. Nelson
- Department of Pharmacology; University of Vermont College of Medicine; Burlington Vermont
| | - Marilyn J. Cipolla
- Department of Neurological Sciences; University of Vermont College of Medicine; Burlington Vermont
- Department of Pharmacology; University of Vermont College of Medicine; Burlington Vermont
- Department of Obstetrics, Gynecology & Reproductive Sciences; University of Vermont College of Medicine; Burlington Vermont
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8
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Diaz JR, Kim KJ, Brands MW, Filosa JA. Augmented astrocyte microdomain Ca 2+ dynamics and parenchymal arteriole tone in angiotensin II-infused hypertensive mice. Glia 2018; 67:551-565. [PMID: 30506941 DOI: 10.1002/glia.23564] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 10/22/2018] [Accepted: 10/22/2018] [Indexed: 11/09/2022]
Abstract
Hypertension is an important contributor to cognitive decline but the underlying mechanisms are unknown. Although much focus has been placed on the effect of hypertension on vascular function, less is understood of its effects on nonvascular cells. Because astrocytes and parenchymal arterioles (PA) form a functional unit (neurovascular unit), we tested the hypothesis that hypertension-induced changes in PA tone concomitantly increases astrocyte Ca2+ . We used cortical brain slices from 8-week-old mice to measure myogenic responses from pressurized and perfused PA. Chronic hypertension was induced in mice by 28-day angiotensin II (Ang II) infusion; PA resting tone and myogenic responses increased significantly. In addition, chronic hypertension significantly increased spontaneous Ca2+ events within astrocyte microdomains (MD). Similarly, a significant increase in astrocyte Ca2+ was observed during PA myogenic responses supporting enhanced vessel-to-astrocyte signaling. The transient potential receptor vanilloid 4 (TRPV4) channel, expressed in astrocyte processes in contact with blood vessels, namely endfeet, respond to hemodynamic stimuli such as increased pressure/flow. Supporting a role for TRPV4 channels in aberrant astrocyte Ca2+ dynamics in hypertension, cortical astrocytes from hypertensive mice showed augmented TRPV4 channel expression, currents and Ca2+ responses to the selective channel agonist GSK1016790A. In addition, pharmacological TRPV4 channel blockade or genetic deletion abrogated enhanced hypertension-induced increases in PA tone. Together, these data suggest chronic hypertension increases PA tone and Ca2+ events within astrocytes MD. We conclude that aberrant Ca2+ events in astrocyte constitute an early event toward the progression of cognitive decline.
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Affiliation(s)
| | - Ki Jung Kim
- Department of Physiology, Augusta University, Augusta, Georgia
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9
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Cipolla MJ, Liebeskind DS, Chan SL. The importance of comorbidities in ischemic stroke: Impact of hypertension on the cerebral circulation. J Cereb Blood Flow Metab 2018; 38:2129-2149. [PMID: 30198826 PMCID: PMC6282213 DOI: 10.1177/0271678x18800589] [Citation(s) in RCA: 180] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Comorbidities are a hallmark of stroke that both increase the incidence of stroke and worsen outcome. Hypertension is prevalent in the stroke population and the most important modifiable risk factor for stroke. Hypertensive disorders promote stroke through increased shear stress, endothelial dysfunction, and large artery stiffness that transmits pulsatile flow to the cerebral microcirculation. Hypertension also promotes cerebral small vessel disease through several mechanisms, including hypoperfusion, diminished autoregulatory capacity and localized increase in blood-brain barrier permeability. Preeclampsia, a hypertensive disorder of pregnancy, also increases the risk of stroke 4-5-fold compared to normal pregnancy that predisposes women to early-onset cognitive impairment. In this review, we highlight how comorbidities and concomitant disorders are not only risk factors for ischemic stroke, but alter the response to acute ischemia. We focus on hypertension as a comorbidity and its effects on the cerebral circulation that alters the pathophysiology of ischemic stroke and should be considered in guiding future therapeutic strategies.
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Affiliation(s)
- Marilyn J Cipolla
- 1 Department of Neurological Sciences, University of Vermont Larner College of Medicine, Burlington, VT, USA
| | - David S Liebeskind
- 2 Neurovascular Imaging Research Core and Stroke Center, Department of Neurology, University of California at Los Angeles, Los Angeles, CA, USA
| | - Siu-Lung Chan
- 1 Department of Neurological Sciences, University of Vermont Larner College of Medicine, Burlington, VT, USA
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10
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Jelinic M, Marshall SA, Leo CH, Parry LJ, Tare M. From pregnancy to cardiovascular disease: Lessons from relaxin-deficient animals to understand relaxin actions in the vascular system. Microcirculation 2018; 26:e12464. [DOI: 10.1111/micc.12464] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 05/30/2018] [Indexed: 12/31/2022]
Affiliation(s)
- Maria Jelinic
- School of BioSciences; University of Melbourne; Parkville VIC Australia
- Department of Physiology, Anatomy & Microbiology; La Trobe University; Bundoora VIC Australia
| | - Sarah A. Marshall
- School of BioSciences; University of Melbourne; Parkville VIC Australia
- Department of Obstetrics and Gynaecology; School of Clinical Sciences; Monash University; Clayton VIC Australia
| | - Chen H. Leo
- School of BioSciences; University of Melbourne; Parkville VIC Australia
- Science and Maths Cluster; Singapore University of Technology & Design; Singapore Singapore
| | - Laura J. Parry
- School of BioSciences; University of Melbourne; Parkville VIC Australia
| | - Marianne Tare
- Department of Physiology; Monash University; Melbourne VIC Australia
- Monash Rural Health; Monash University; Melbourne VIC Australia
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11
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Jelinic M, Marshall SA, Stewart D, Unemori E, Parry LJ, Leo CH. Peptide hormone relaxin: from bench to bedside. Am J Physiol Regul Integr Comp Physiol 2018; 314:R753-R760. [DOI: 10.1152/ajpregu.00276.2017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The peptide hormone relaxin has numerous roles both within and independent of pregnancy and is often thought of as a “pleiotropic hormone.” Relaxin targets several tissues throughout the body, and has many functions associated with extracellular matrix remodeling and the vasculature. This review considers the potential therapeutic applications of relaxin in cervical ripening, in vitro fertilization, preeclampsia, acute heart failure, ischemia-reperfusion, and cirrhosis. We first outline the animal models used in preclinical studies to progress relaxin into clinical trials and then discuss the findings from these studies. In many cases, the positive outcomes from preclinical animal studies were not replicated in human clinical trials. Therefore, the focus of this review is to evaluate the various animal models used to develop relaxin as a potential therapeutic and consider the limitations that must be addressed in future studies. These include the use of human relaxin in animals, duration of relaxin treatment, and the appropriateness of the clinical conditions being considered for relaxin therapy.
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Affiliation(s)
- Maria Jelinic
- School of BioSciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Sarah A. Marshall
- School of BioSciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Dennis Stewart
- Molecular Medicine Research Institute, Sunnyvale, California
| | | | - Laura J. Parry
- School of BioSciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Chen Huei Leo
- School of BioSciences, The University of Melbourne, Parkville, Victoria, Australia
- Science and Maths Cluster, Singapore University of Technology and Design, Singapore
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12
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Jelinic M, Leo CH, Marshall SA, Senadheera SN, Parry LJ, Tare M. Short-term (48 hours) intravenous serelaxin infusion has no effect on myogenic tone or vascular remodeling in rat mesenteric arteries. Microcirculation 2018; 24. [PMID: 28370794 DOI: 10.1111/micc.12371] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 03/24/2017] [Indexed: 01/08/2023]
Abstract
BACKGROUND Short-term IV sRLX (recombinant human relaxin-2) infusion enhances endothelium-dependent relaxation in mesenteric arteries. This is initially underpinned by increased NO followed by a transition to prostacyclin. The effects of short-term IV sRLX treatment on pressure-induced myogenic tone and vascular remodeling in these arteries are unknown. Therefore, we investigated the effects of sRLX infusion on pressure-induced myogenic tone and passive mechanical wall properties in mesenteric arteries. METHODS Mesenteric artery myogenic tone and passive mechanics were examined after 48-hours and 10-days infusion of sRLX. Potential mechanisms of action were assessed by pressure myography, qPCR, and Western blot analysis. RESULTS Neither 48-hours nor 10-days sRLX treatment had significant effects on myogenic tone, passive arterial wall stiffness, volume compliance, or axial lengthening. However, in 48-hours sRLX -treated rats, incubation with the NO synthase blocker L-NAME significantly increased myogenic tone (P<.05 vs placebo), demonstrating an increased contribution of NO to the regulation of myogenic tone. eNOS dimerization, but not phosphorylation, was significantly upregulated in the arteries of sRLX -treated rats. CONCLUSION In mesenteric arteries, 48-hours sRLX treatment upregulates the role of NO in the regulation of myogenic tone by enhancing eNOS dimerization, without altering overall myogenic tone or vascular remodeling.
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Affiliation(s)
- Maria Jelinic
- School of BioSciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Chen Huei Leo
- School of BioSciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Sarah A Marshall
- School of BioSciences, The University of Melbourne, Parkville, Victoria, Australia
| | | | - Laura J Parry
- School of BioSciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Marianne Tare
- Department of Physiology, Monash University, Clayton, Victoria, Australia.,Monash Rural Health, Monash University, Churchill, Victoria, Australia
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13
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Ng HH, Leo CH, Parry LJ, Ritchie RH. Relaxin as a Therapeutic Target for the Cardiovascular Complications of Diabetes. Front Pharmacol 2018; 9:501. [PMID: 29867503 PMCID: PMC5962677 DOI: 10.3389/fphar.2018.00501] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 04/26/2018] [Indexed: 12/13/2022] Open
Abstract
Cardiovascular complications are the major cause of mortality in patients with diabetes. This is closely associated with both macrovascular and microvascular complications of diabetes, which lead to organ injuries in diabetic patients. Previous studies have consistently demonstrated the beneficial effects of relaxin treatment for protection of the vasculature, with evidence of antioxidant and anti-remodeling actions. Relaxin enhances nitric oxide, prostacyclin and endothelium-derived hyperpolarization (EDH)-type-mediated relaxation in various vascular beds. These effects of relaxin on the systemic vasculature, coupled with its cardiac actions, reduce pulmonary capillary wedge pressure and pulmonary artery pressure. This results in an overall decrease in systemic and pulmonary vascular resistance in heart failure patients. The anti-fibrotic actions of relaxin are well established, a desirable property in the context of diabetes. Further, relaxin ameliorates diabetic wound healing, with accelerated angiogenesis and vasculogenesis. Relaxin-mediated stimulation of vascular endothelial growth factor (VEGF) and stromal cell-derived factor 1-α, as well as regulation of metalloproteinase expression, ameliorates cardiovascular fibrosis in diabetic mice. In the heart, relaxin is a cardioprotective molecule in several experimental animal models, exerting anti-fibrotic, anti-hypertrophy and anti-apoptotic effects in diabetic pathologies. Collectively, these studies provide a foundation to propose the therapeutic potential for relaxin as an adjunctive agent in the prevention or treatment of diabetes-induced cardiovascular complications. This review provides a comprehensive overview of the beneficial effects of relaxin, and identifies its therapeutic possibilities for alleviating diabetes-related cardiovascular injury.
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Affiliation(s)
- Hooi Hooi Ng
- School of BioSciences, The University of Melbourne, Melbourne, VIC, Australia
- Heart Failure Pharmacology, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
- Department of Human and Molecular Genetics, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, United States
| | - Chen Huei Leo
- School of BioSciences, The University of Melbourne, Melbourne, VIC, Australia
- Science and Math Cluster, Singapore University of Technology and Design, Singapore, Singapore
| | - Laura J. Parry
- School of BioSciences, The University of Melbourne, Melbourne, VIC, Australia
| | - Rebecca H. Ritchie
- Heart Failure Pharmacology, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
- Department of Pharmacology & Therapeutics, The University of Melbourne, Melbourne, VIC, Australia
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14
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Bennett RG. Targeting the Relaxin Pathway for Liver Disease Treatment. EUROPEAN MEDICAL JOURNAL. HEPATOLOGY 2018; 6:80-87. [PMID: 31360529 PMCID: PMC6662909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Hepatic fibrosis is a progressive disease with few treatment options outside of transplantation. Relaxin is a member of the insulin/relaxin superfamily of peptide hormones. Originally known for its roles in pregnancy, relaxin promotes reproductive tissue remodelling and regulates vascular changes, including increased arterial compliance and reduced vascular resistance. Outside of pregnancy, relaxin plays a major role in the protection of organs from excess extracellular matrix accumulation, as demonstrated by the relaxin-null mouse, which develops widespread fibrosis with ageing. Relaxin reduces scarring due to excess collagen deposition by inhibiting collagen production while simultaneously promoting its degradation and can reduce established fibrosis in several animal models of extracellular matrix-associated disease, including liver fibrosis. Treatment with relaxin reduces the myofibroblastic phenotype of activated hepatic stellate cells, the major hepatic collagen-producing cell in fibrosis and cirrhosis. Relaxin also has haemodynamic effects, including vasodilation, and can reduce portal hypertension associated with cirrhosis. In this review, a brief overview of hepatic fibrosis and the role of the hepatic stellate cell will be presented, followed by an introduction to relaxin and its actions. The use of relaxin to treat preclinical models of fibrotic diseases, including liver diseases, will also be discussed. Finally, the completed, current, and ongoing clinical trials of relaxin in human disease will be described, followed by the limitations and future directions for the use of relaxin for disease treatment.
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15
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Nistor M, Schmidt M, Schiffner R. The relaxin peptide family - potential future hope for neuroprotective therapy? A short review. Neural Regen Res 2018; 13:402-405. [PMID: 29623915 PMCID: PMC5900493 DOI: 10.4103/1673-5374.228713] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Since its discovery in the 1920's the relaxin peptide hormone family has not only grown in number to now seven members (relaxin-1, relaxin-2, relaxin-3, insulin-like peptide (INSL) 3, INSL4, INSL5 and INSL6), but ever more effects, suchs as vasodilatory, angiogenic, anti-apoptopic, anti-fibriotic and anti-inflammatory, have been linked to them. While relaxin-2 has mainly been investigated in the context of cardiac protection, most comprehensively in the RELAX-AHF and RELAX AHF2 studies, a small number of studies have furthermore assessed the potential neuroprotective effects of especially relaxin-2 and other members of the relaxin family. In this short review we summarise and discuss recent efforts to utilize relaxin hormones for neuroprotection and point out potential future fields of research and translational applications. While many questions still need to be answered, the promising results of the available studies definitely warrant future well-designed studies on neuroprotection by relaxin peptides.
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Affiliation(s)
- Marius Nistor
- Department of Neurology, Jena University Hospital, Friedrich Schiller University, Jena, Germany
| | - Martin Schmidt
- Institute for Biochemistry II, Jena University Hospital, Friedrich Schiller University, Jena, Germany
| | - René Schiffner
- Department of Neurology, Jena University Hospital, Friedrich Schiller University; Orthopaedic Department, Jena University Hospital, Friedrich Schiller University, Jena, Germany
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16
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Abstract
Fibrosis is a major player in cardiovascular disease, both as a contributor to the development of disease, as well as a post-injury response that drives progression. Despite the identification of many mechanisms responsible for cardiovascular fibrosis, to date no treatments have emerged that have effectively reduced the excess deposition of extracellular matrix associated with fibrotic conditions. Novel treatments have recently been identified that hold promise as potential therapeutic agents for cardiovascular diseases associated with fibrosis, as well as other fibrotic conditions. The purpose of this review is to provide an overview of emerging antifibrotic agents that have shown encouraging results in preclinical or early clinical studies, but have not yet been approved for use in human disease. One of these agents is bone morphogenetic protein-7 (BMP7), which has beneficial effects in multiple models of fibrotic disease. Another approach discussed involves altering the levels of micro-RNA (miR) species, including miR-29 and miR-101, which regulate the expression of fibrosis-related gene targets. Further, the antifibrotic potential of agonists of the peroxisome proliferator-activated receptors will be discussed. Finally, evidence will be reviewed in support of the polypeptide hormone relaxin. Relaxin is long known for its extracellular remodeling properties in pregnancy, and is rapidly emerging as an effective antifibrotic agent in a number of organ systems. Moreover, relaxin has potent vascular and renal effects that make it a particularly attractive approach for the treatment of cardiovascular diseases. In each case, the mechanism of action and the applicability to various fibrotic diseases will be discussed.
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Affiliation(s)
- Benita L McVicker
- Research Service, VA Nebraska-Western Iowa Health Care System, OmahaNE, United States.,Division of Gastroenterology and Hepatology, University of Nebraska Medical Center, OmahaNE, United States
| | - Robert G Bennett
- Research Service, VA Nebraska-Western Iowa Health Care System, OmahaNE, United States.,The Division of Diabetes, Endocrinology, and Metabolism, Department of Internal Medicine, University of Nebraska Medical Center, OmahaNE, United States.,Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, OmahaNE, United States
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17
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Russo E, Leo A, Scicchitano F, Donato A, Ferlazzo E, Gasparini S, Cianci V, Mignogna C, Donato G, Citraro R, Aguglia U, De Sarro G. Cerebral small vessel disease predisposes to temporal lobe epilepsy in spontaneously hypertensive rats. Brain Res Bull 2017; 130:245-250. [PMID: 28214547 DOI: 10.1016/j.brainresbull.2017.02.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2017] [Revised: 01/30/2017] [Accepted: 02/13/2017] [Indexed: 01/13/2023]
Abstract
The link between cerebral small vessel disease (CSVD) and epilepsy has been poorly investigated. Some reports suggest that CSVD may predispose to temporal lobe epilepsy (TLE). Aim of this study was to evaluate whether spontaneously hypertensive rats (SHRs), an established model of systemic hypertension and CSVD, have a propensity to develop TLE more than generalized seizures. To this aim, amygdala kindling, as a model of TLE, and pentylenetetrazole (PTZ)-induced kindling, as a model of generalized seizures, have been used to ascertain whether SHRs are more prone to TLE as compared to Wistar Kyoto control rats. While young SHRs (without CSVD) do not differ from their age-matched controls in both models, old SHRs (with CSVD) develop stage 5 seizures in the amygdala kindling model (TLE) faster than age-matched control rats without CSVD. At odds, no differences between old SHRs and age-matched controls was observed in the development of PTZ kindling. Enalapril pre-treatment prevented the development of CSVD and normalized kindling development to control levels in SHRs. No difference was observed in the response to pharmacological treatment with carbamazepine or losartan. Overall, our study suggests that uncontrolled hypertension leading to CSVD might represent a risk factor for TLE. Further experimental studies are needed to unravel other risk factors that, along with CSVD, may predispose to TLE.
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Affiliation(s)
- Emilio Russo
- Science of Health Department, School of Medicine, University "Magna Graecia" of Catanzaro, Italy.
| | - Antonio Leo
- Science of Health Department, School of Medicine, University "Magna Graecia" of Catanzaro, Italy
| | - Francesca Scicchitano
- Science of Health Department, School of Medicine, University "Magna Graecia" of Catanzaro, Italy
| | - Annalidia Donato
- Science of Health Department, School of Medicine, University "Magna Graecia" of Catanzaro, Italy
| | - Edoardo Ferlazzo
- Regional Epilepsy Centre, Bianchi-Melacrino-Morelli Hospital, Reggio Calabria, Italy; Medical and Surgical Sciences Department, School of Medicine, Magna Græcia University of Catanzaro, Viale Europa, Catanzaro, Italy
| | - Sara Gasparini
- Regional Epilepsy Centre, Bianchi-Melacrino-Morelli Hospital, Reggio Calabria, Italy; Medical and Surgical Sciences Department, School of Medicine, Magna Græcia University of Catanzaro, Viale Europa, Catanzaro, Italy
| | - Vittoria Cianci
- Regional Epilepsy Centre, Bianchi-Melacrino-Morelli Hospital, Reggio Calabria, Italy
| | - Chiara Mignogna
- Science of Health Department, School of Medicine, University "Magna Graecia" of Catanzaro, Italy
| | - Giuseppe Donato
- Science of Health Department, School of Medicine, University "Magna Graecia" of Catanzaro, Italy
| | - Rita Citraro
- Science of Health Department, School of Medicine, University "Magna Graecia" of Catanzaro, Italy
| | - Umberto Aguglia
- Regional Epilepsy Centre, Bianchi-Melacrino-Morelli Hospital, Reggio Calabria, Italy; Medical and Surgical Sciences Department, School of Medicine, Magna Græcia University of Catanzaro, Viale Europa, Catanzaro, Italy
| | - Giovambattista De Sarro
- Science of Health Department, School of Medicine, University "Magna Graecia" of Catanzaro, Italy
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18
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Hu X, De Silva TM, Chen J, Faraci FM. Cerebral Vascular Disease and Neurovascular Injury in Ischemic Stroke. Circ Res 2017; 120:449-471. [PMID: 28154097 PMCID: PMC5313039 DOI: 10.1161/circresaha.116.308427] [Citation(s) in RCA: 256] [Impact Index Per Article: 36.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 10/13/2016] [Accepted: 10/26/2016] [Indexed: 12/13/2022]
Abstract
The consequences of cerebrovascular disease are among the leading health issues worldwide. Large and small cerebral vessel disease can trigger stroke and contribute to the vascular component of other forms of neurological dysfunction and degeneration. Both forms of vascular disease are driven by diverse risk factors, with hypertension as the leading contributor. Despite the importance of neurovascular disease and subsequent injury after ischemic events, fundamental knowledge in these areas lag behind our current understanding of neuroprotection and vascular biology in general. The goal of this review is to address select key structural and functional changes in the vasculature that promote hypoperfusion and ischemia, while also affecting the extent of injury and effectiveness of therapy. In addition, as damage to the blood-brain barrier is one of the major consequences of ischemia, we discuss cellular and molecular mechanisms underlying ischemia-induced changes in blood-brain barrier integrity and function, including alterations in endothelial cells and the contribution of pericytes, immune cells, and matrix metalloproteinases. Identification of cell types, pathways, and molecules that control vascular changes before and after ischemia may result in novel approaches to slow the progression of cerebrovascular disease and lessen both the frequency and impact of ischemic events.
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Affiliation(s)
- Xiaoming Hu
- Center of Cerebrovascular Disease Research, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213
| | - T. Michael De Silva
- Biomedicine Discovery Institute, Department of Pharmacology, 9 Ancora Imparo Way, Monash University, Clayton, Vic, Australia
| | - Jun Chen
- Center of Cerebrovascular Disease Research, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213
| | - Frank M. Faraci
- Departments of Internal Medicine and Pharmacology, Carver College of Medicine, University of Iowa, Iowa City Veterans Affairs Healthcare System, Iowa City, IA, USA
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19
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De Silva TM, Faraci FM. Reactive Oxygen Species and the Regulation of Cerebral Vascular Tone. STUDIES ON ATHEROSCLEROSIS 2017. [DOI: 10.1007/978-1-4899-7693-2_6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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20
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Meissner A, Minnerup J, Soria G, Planas AM. Structural and functional brain alterations in a murine model of Angiotensin II-induced hypertension. J Neurochem 2016; 140:509-521. [DOI: 10.1111/jnc.13905] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Revised: 11/07/2016] [Accepted: 11/09/2016] [Indexed: 01/18/2023]
Affiliation(s)
- Anja Meissner
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS); Barcelona Spain
- Department of Neurology; University Hospital Münster; Münster Germany
| | - Jens Minnerup
- Department of Neurology; University Hospital Münster; Münster Germany
| | - Guadalupe Soria
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS); Barcelona Spain
| | - Anna M Planas
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS); Barcelona Spain
- Departament d'Isquèmia Cerebral i Neurodegeneració; Institut d'Investigacions Biomèdiques de Barcelona (IIBB); Consejo Superior de Investigaciones Científicas (CSIC); Barcelona Spain
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21
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Jelinic M, Kahlberg N, Parry LJ, Tare M. Does serelaxin treatment alter passive mechanical wall properties in small resistance arteries? Microcirculation 2016; 23:631-636. [DOI: 10.1111/micc.12321] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 09/15/2016] [Indexed: 11/26/2022]
Affiliation(s)
- Maria Jelinic
- School of BioSciences; The University of Melbourne; Parkville Victoria Australia
| | - Nicola Kahlberg
- School of BioSciences; The University of Melbourne; Parkville Victoria Australia
| | - Laura J. Parry
- School of BioSciences; The University of Melbourne; Parkville Victoria Australia
| | - Marianne Tare
- Department of Physiology; Monash University; Parkville Victoria Australia
- School of Rural Health; Monash University; Parkville Victoria Australia
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22
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Leo CH, Jelinic M, Ng HH, Marshall SA, Novak J, Tare M, Conrad KP, Parry LJ. Vascular actions of relaxin: nitric oxide and beyond. Br J Pharmacol 2016; 174:1002-1014. [PMID: 27590257 DOI: 10.1111/bph.13614] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 08/24/2016] [Accepted: 08/29/2016] [Indexed: 12/28/2022] Open
Abstract
The peptide hormone relaxin regulates the essential maternal haemodynamic adaptations in early pregnancy through direct actions on the renal and systemic vasculature. These vascular actions of relaxin occur mainly through endothelium-derived NO-mediated vasodilator pathways and improvements in arterial compliance in small resistance-size arteries. This work catalysed a plethora of studies which revealed quite heterogeneous responses across the different regions of the vasculature, and also uncovered NO-independent mechanisms of relaxin action. In this review, we first describe the role of endogenous relaxin in maintaining normal vascular function, largely referring to work in pregnant and male relaxin-deficient animals. We then discuss the diversity of mechanisms mediating relaxin action in different vascular beds, including the involvement of prostanoids, VEGF, endothelium-derived hyperpolarisation and antioxidant activity in addition to the classic NO-mediated vasodilatory pathway. We conclude the review with current perspectives on the vascular remodelling capabilities of relaxin. LINKED ARTICLES This article is part of a themed section on Recent Progress in the Understanding of Relaxin Family Peptides and their Receptors. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.10/issuetoc.
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Affiliation(s)
- C H Leo
- School of BioSciences, The University of Melbourne, Parkville, VIC, Australia
| | - M Jelinic
- School of BioSciences, The University of Melbourne, Parkville, VIC, Australia
| | - H H Ng
- School of BioSciences, The University of Melbourne, Parkville, VIC, Australia
| | - S A Marshall
- School of BioSciences, The University of Melbourne, Parkville, VIC, Australia
| | - J Novak
- Division of Mathematics and Science, Walsh University, North Canton, OH, USA
| | - M Tare
- Department of Physiology, Monash University, Clayton, VIC, Australia.,School of Rural Health, Monash University, Clayton, VIC, Australia
| | - K P Conrad
- Department of Physiology and Functional Genomics, Department of Obstetrics and Gynaecology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - L J Parry
- School of BioSciences, The University of Melbourne, Parkville, VIC, Australia
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23
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Bischoff SJ, Schmidt M, Lehmann T, Irintchev A, Schubert H, Jung C, Schwab M, Huber O, Matziolis G, Schiffner R. Increase of cortical cerebral blood flow and further cerebral microcirculatory effects of Serelaxin in a sheep model. Am J Physiol Heart Circ Physiol 2016; 311:H613-20. [PMID: 27402664 DOI: 10.1152/ajpheart.00118.2016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 07/02/2016] [Indexed: 12/17/2022]
Abstract
Serelaxin, recombinant human relaxin-2, modulates endothelial vasodilatory functionality and is under evaluation for treatment of acute heart failure. Little is known about acute effects on cerebral perfusion. We tested the hypothesis that Serelaxin might also have effects on the cerebral microcirculation in a sheep model, which resembles human brain structure quite well. We used laser Doppler flowmetry and sidestream dark-field (SDF) imaging techniques, which are reliable tools to continuously assess dynamic changes in cerebral perfusion. Laser Doppler flowmetry shows that bolus injection of 30 μg Serelaxin/kg body wt induces an increase (P = 0.006) to roughly 150% of cortical cerebral blood flow (CBF), whereas subcortical CBF remains unchanged (P = 0.688). The effects on area-dependent CBF were significantly different after the bolus injection (P = 0.042). Effects on cortical CBF were further confirmed by SDF imaging. The bolus injection of Serelaxin increased total vessel density to 127% (P = 0.00046), perfused vessel density to 145% (P = 0.024), and perfused capillary density to 153% (P = 0.024). Western blotting confirmed the expression of relaxin receptors RXFP1 and truncated RXFP2-variants in the respective brain regions, suggesting a possible contribution of RXFP1 on the effects of Serelaxin. In conclusion, the injection of a high dose of Serelaxin exerts quick effects on the cerebral microcirculation. Therefore, Serelaxin might be suitable to improve cortical microcirculation and exert neuroprotective effects in clinically relevant scenarios that involve cortical hypoperfusion. These findings need to be confirmed in relevant experimental settings involving cerebral cortical hypoperfusion and can possibly be translated into clinical practice.
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Affiliation(s)
- Sabine J Bischoff
- Institute for Laboratory Animal Science and Welfare, Jena University Hospital, Friedrich Schiller University, Jena, Germany
| | - Martin Schmidt
- Institute for Biochemistry II, Jena University Hospital, Friedrich Schiller University, Jena, Germany
| | - Thomas Lehmann
- Institute of Medical Statistics, Computer Sciences and Documentation Science, Jena University Hospital, Friedrich Schiller University, Jena, Germany
| | - Andrey Irintchev
- Department of Otorhinolaryngology, Jena University Hospital, Friedrich Schiller University, Jena, Germany
| | - Harald Schubert
- Institute for Laboratory Animal Science and Welfare, Jena University Hospital, Friedrich Schiller University, Jena, Germany
| | - Christian Jung
- Division of Cardiology, Pulmonology and Vascular Medicine, University Hospital Düsseldorf, Heinrich-Heine-University, Düsseldorf, Germany
| | - Matthias Schwab
- Department of Neurology, Jena University Hospital, Friedrich Schiller University, Jena, Germany; and
| | - Otmar Huber
- Institute for Biochemistry II, Jena University Hospital, Friedrich Schiller University, Jena, Germany
| | - Georg Matziolis
- Orthopaedic Department, Jena University Hospital, Friedrich Schiller University, Jena, Germany
| | - René Schiffner
- Department of Neurology, Jena University Hospital, Friedrich Schiller University, Jena, Germany; and Orthopaedic Department, Jena University Hospital, Friedrich Schiller University, Jena, Germany
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24
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Serelaxin: A Novel Therapeutic for Vascular Diseases. Trends Pharmacol Sci 2016; 37:498-507. [PMID: 27130518 DOI: 10.1016/j.tips.2016.04.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 03/31/2016] [Accepted: 04/04/2016] [Indexed: 12/19/2022]
Abstract
Vascular dysfunction is an important hallmark of cardiovascular disease. It is characterized by increased sensitivity to vasoconstrictors, decreases in the endothelium-derived vasodilators nitric oxide (NO) and prostacyclin (PGI2), and endothelium-derived hyperpolarization (EDH). Serelaxin (recombinant human relaxin) has gained considerable attention as a new vasoactive drug, largely through its beneficial therapeutic effects in acute heart failure. In this review we first describe the contribution of endogenous relaxin to vascular homeostasis. We then provide a comprehensive overview of the novel mechanisms of serelaxin action in blood vessels that differentiate it from other vasodilator drugs and explain how this peptide could be used more widely as a therapeutic to alleviate vascular dysfunction in several cardiovascular diseases.
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25
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Microvascular Dysfunction and Cognitive Impairment. Cell Mol Neurobiol 2016; 36:241-58. [PMID: 26988697 DOI: 10.1007/s10571-015-0308-1] [Citation(s) in RCA: 106] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 11/19/2015] [Indexed: 12/18/2022]
Abstract
The impact of vascular risk factors on cognitive function has garnered much interest in recent years. The appropriate distribution of oxygen, glucose, and other nutrients by the cerebral vasculature is critical for proper cognitive performance. The cerebral microvasculature is a key site of vascular resistance and a preferential target for small vessel disease. While deleterious effects of vascular risk factors on microvascular function are known, the contribution of this dysfunction to cognitive deficits is less clear. In this review, we summarize current evidence for microvascular dysfunction in brain. We highlight effects of select vascular risk factors (hypertension, diabetes, and hyperhomocysteinemia) on the pial and parenchymal circulation. Lastly, we discuss potential links between microvascular disease and cognitive function, highlighting current gaps in our understanding.
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26
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Sarwar M, Samuel CS, Bathgate RA, Stewart DR, Summers RJ. Enhanced serelaxin signalling in co-cultures of human primary endothelial and smooth muscle cells. Br J Pharmacol 2016; 173:484-96. [PMID: 26493539 DOI: 10.1111/bph.13371] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Revised: 10/06/2015] [Accepted: 10/10/2015] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND AND PURPOSE In the phase III clinical trial, RELAX-AHF, serelaxin caused rapid and long-lasting haemodynamic changes. However, the cellular mechanisms involved are unclear in humans. EXPERIMENTAL APPROACH This study examined the effects of serelaxin in co-cultures of human primary endothelial cells (ECs) and smooth muscle cells (SMCs) on cAMP and cGMP signalling. KEY RESULTS Stimulation of HUVECs or human coronary artery endothelial cells (HCAECs) with serelaxin, concentration-dependently increased cGMP accumulation in co-cultured SMCs to a greater extent than in monocultures of either cell type. This was not observed in human umbilical artery endothelial cells (HUAECs) that do not express the relaxin receptor, RXFP1. Treatment of ECs with l-N(G) -nitro arginine (NOARG; 30 μM, 30 min) inhibited serelaxin-mediated (30 nM) cGMP accumulation in HUVECs, HCAECs and co-cultured SMCs. In HCAECs, but not HUVECs, pre-incubation with indomethacin (30 μM, 30 min) also inhibited cGMP accumulation in SMCs. Pre-incubation of SMCs with the guanylate cyclase inhibitor ODQ (1 μM, 30 min) had no effect on serelaxin-mediated (30 nM) cGMP accumulation in HUVECs and HCAECs but inhibited cGMP accumulation in SMCs. Serelaxin stimulation of HCAECs, but not HUVECs, increased cAMP accumulation concentration-dependently in SMCs. Pre-incubation of HCAECs with indomethacin, but not l-NOARG, abolished cAMP accumulation in co-cultured SMCs, suggesting involvement of prostanoids. CONCLUSIONS AND IMPLICATIONS In co-cultures, treatment of ECs with serelaxin caused marked cGMP accumulation in SMCs and with HCAEC also cAMP accumulation. Responses involved EC-derived NO and with HCAEC prostanoid production. Thus, serelaxin differentially modulates vascular tone in different vascular beds.
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Affiliation(s)
- M Sarwar
- Drug Discovery Biology, Monash Institute of Pharmacology, Monash University, Australia
| | - C S Samuel
- Department of Pharmacology, Monash University, Australia
| | - R A Bathgate
- The Florey Institute of Neuroscience and Mental Health and the Department of Biochemistry and Molecular Biology, University of Melbourne, Australia
| | | | - R J Summers
- Drug Discovery Biology, Monash Institute of Pharmacology, Monash University, Australia
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27
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Abstract
Basal and activity-dependent cerebral blood flow changes are coordinated by the action of critical processes, including cerebral autoregulation, endothelial-mediated signaling, and neurovascular coupling. The goal of our study was to determine whether astrocytes contribute to the regulation of parenchymal arteriole (PA) tone in response to hemodynamic stimuli (pressure/flow). Cortical PA vascular responses and astrocytic Ca(2+) dynamics were measured using an in vitro rat/mouse brain slice model of perfused/pressurized PAs; studies were supplemented with in vivo astrocytic Ca(2+) imaging. In vitro, astrocytes responded to PA flow/pressure increases with an increase in intracellular Ca(2+). Astrocytic Ca(2+) responses were corroborated in vivo, where acute systemic phenylephrine-induced increases in blood pressure evoked a significant increase in astrocytic Ca(2+). In vitro, flow/pressure-evoked vasoconstriction was blunted when the astrocytic syncytium was loaded with BAPTA (chelating intracellular Ca(2+)) and enhanced when high Ca(2+) or ATP were introduced to the astrocytic syncytium. Bath application of either the TRPV4 channel blocker HC067047 or purinergic receptor antagonist suramin blunted flow/pressure-evoked vasoconstriction, whereas K(+) and 20-HETE signaling blockade showed no effect. Importantly, we found TRPV4 channel expression to be restricted to astrocytes and not the endothelium of PA. We present evidence for a novel role of astrocytes in PA flow/pressure-evoked vasoconstriction. Our data suggest that astrocytic TRPV4 channels are key molecular sensors of hemodynamic stimuli and that a purinergic, glial-derived signal contributes to flow/pressure-induced adjustments in PA tone. Together our results support bidirectional signaling within the neurovascular unit and astrocytes as key modulators of PA tone.
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Pires PW, Jackson WF, Dorrance AM. Regulation of myogenic tone and structure of parenchymal arterioles by hypertension and the mineralocorticoid receptor. Am J Physiol Heart Circ Physiol 2015; 309:H127-36. [PMID: 25910805 DOI: 10.1152/ajpheart.00168.2015] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 04/23/2015] [Indexed: 11/22/2022]
Abstract
Proper perfusion is vital for maintenance of neuronal homeostasis and brain function. Changes in the function and structure of cerebral parenchymal arterioles (PAs) could impair blood flow regulation and increase the risk of cerebrovascular diseases, including dementia and stroke. Hypertension alters the structure and function of large cerebral arteries, but its effects on PAs remain unknown. We hypothesized that hypertension increases myogenic tone and induces inward remodeling in PAs; we further proposed that antihypertensive therapy or mineralocorticoid receptor (MR) blockade would reverse the effects of hypertension. PAs from 18-wk-old stroke-prone spontaneously hypertensive rats (SHRSP) were isolated and cannulated in a pressure myograph. At 50-mmHg intraluminal pressure, PAs from SHRSP showed higher myogenic tone (%tone: 39.1 ± 1.9 vs. 28.7 ± 2.5%, P < 0.01) and smaller resting luminal diameter (34.7 ± 1.9 vs. 46.2 ± 2.4 μm, P < 0.01) than those from normotensive Wistar-Kyoto rats, through a mechanism that seems to require Ca(2+) influx through L-type voltage-gated Ca(2+) channels. PAs from SHRSP showed inward remodeling (luminal diameter at 60 mmHg: 55.2 ± 1.4 vs. 75.7 ± 5.1 μm, P < 0.01) and a paradoxical increase in distensibility and compliance. Treatment of SHRSP for 6 wk with antihypertensive therapy reduced PAs' myogenic tone, increased their resting luminal diameter, and prevented inward remodeling. In contrast, treatment of SHRSP for 6 wk with an MR antagonist did not reduce blood pressure or myogenic tone, but prevented inward remodeling. Thus, while hypertensive remodeling of PAs may involve the MR, myogenic tone seems to be independent of MR activity.
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Affiliation(s)
- Paulo W Pires
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan; and Department of Pharmacology, University of Nevada School of Medicine, Reno, Nevada
| | - William F Jackson
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan; and
| | - Anne M Dorrance
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan; and
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Singh S, Simpson RL, Bennett RG. Relaxin activates peroxisome proliferator-activated receptor γ (PPARγ) through a pathway involving PPARγ coactivator 1α (PGC1α). J Biol Chem 2014; 290:950-9. [PMID: 25389293 DOI: 10.1074/jbc.m114.589325] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Relaxin activation of its receptor RXFP1 triggers multiple signaling pathways. Previously, we have shown that relaxin activates PPARγ transcriptional activity in a ligand-independent manner, but the mechanism for this effect was unknown. In this study, we examined the signaling pathways of downstream of RXFP1 leading to PPARγ activation. Using cells stably expressing RXFP1, we found that relaxin regulation of PPARγ activity requires accumulation of cAMP and subsequent activation of cAMP-dependent protein kinase (PKA). The activated PKA subsequently phosphorylated cAMP response element-binding protein (CREB) at Ser-133 to activate it directly, as well as indirectly through mitogen activated protein kinase p38 MAPK. Activated CREB was required for relaxin stimulation of PPARγ activity, while there was no evidence for a role of the nitric oxide or ERK MAPK pathways. Relaxin increased the mRNA and protein levels of the coactivator protein PGC1α, and this effect was dependent on PKA, and was completely abrogated by a dominant-negative form of CREB. This mechanism was confirmed in a hepatic stellate cell line stably that endogenously expresses RXFP1. Reduction of PGC1α levels using siRNA diminished the regulation of PPARγ by relaxin. These results suggest that relaxin activates the cAMP/PKA and p38 MAPK pathways to phosphorylate CREB, resulting in increased PGC1α levels. This provides a mechanism for the ligand-independent activation of PPARγ in response to relaxin.
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Affiliation(s)
- Sudhir Singh
- From the Medical Research Service, The Department of Veterans Affairs, Nebraska-Western Iowa Health Care System, Omaha, Nebraska 68105 and the Departments of Biochemistry & Molecular Biology, Internal Medicine and Pharmacology & Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska 68198
| | - Ronda L Simpson
- From the Medical Research Service, The Department of Veterans Affairs, Nebraska-Western Iowa Health Care System, Omaha, Nebraska 68105 and the Departments of Biochemistry & Molecular Biology, Internal Medicine and Pharmacology & Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska 68198
| | - Robert G Bennett
- From the Medical Research Service, The Department of Veterans Affairs, Nebraska-Western Iowa Health Care System, Omaha, Nebraska 68105 and the Departments of Biochemistry & Molecular Biology, Internal Medicine and Pharmacology & Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska 68198
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Cipolla MJ, Sweet J, Chan SL, Tavares MJ, Gokina N, Brayden JE. Increased pressure-induced tone in rat parenchymal arterioles vs. middle cerebral arteries: role of ion channels and calcium sensitivity. J Appl Physiol (1985) 2014; 117:53-9. [PMID: 24790017 DOI: 10.1152/japplphysiol.00253.2014] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Brain parenchymal arterioles (PAs) are high-resistance vessels that branch off pial arteries and perfuse the brain parenchyma. PAs are the target of cerebral small vessel disease and have been shown to have greater pressure-induced tone at lower pressures than pial arteries. We investigated mechanisms by which brain PAs have increased myogenic tone compared with middle cerebral arteries (MCAs), focusing on differences in vascular smooth muscle (VSM) calcium and ion channel function. The amount of myogenic tone and VSM calcium was measured using Fura 2 in isolated and pressurized PAs and MCAs. Increases in intraluminal pressure caused larger increases in tone and cytosolic calcium in PAs compared with MCAs. At 50 mmHg, myogenic tone was 37 ± 5% for PAs vs. 6.5 ± 4% for MCAs (P < 0.01), and VSM calcium was 200 ± 20 nmol/l in PAs vs. 104 ± 15 nmol/l in MCAs (P < 0.01). In vessels permeabilized with Staphylococcus aureus α-toxin, PAs were not more sensitive to calcium, suggesting calcium sensitization was not at the level of the contractile apparatus. PAs were 30-fold more sensitive to the voltage-dependent calcium channel (VDCC) inhibitor nifedipine than MCAs (EC50 for PAs was 3.5 ± 0.4 vs. 82.1 ± 2.1 nmol/l for MCAs;P < 0.01); however, electrophysiological properties of the VDCC were not different in VSM. PAs had little to no response to the calcium-activated potassium channel inhibitor iberiotoxin, whereas MCAs constricted ∼15%. Thus increased myogenic tone in PAs appears related to differences in ion channel activity that promotes VSM membrane depolarization but not to a direct sensitization of the contractile apparatus to calcium.
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Affiliation(s)
- Marilyn J Cipolla
- Department of Neurological Sciences, University of Vermont, Burlington, Vermont; Department of Pharmacology, University of Vermont, Burlington, Vermont; and Department of Obstetrics, Gynecology & Reproductive Sciences, University of Vermont, Burlington, Vermont
| | - Julie Sweet
- Department of Neurological Sciences, University of Vermont, Burlington, Vermont
| | - Siu-Lung Chan
- Department of Neurological Sciences, University of Vermont, Burlington, Vermont
| | - Matthew J Tavares
- Department of Pharmacology, University of Vermont, Burlington, Vermont; and
| | - Natalia Gokina
- Department of Obstetrics, Gynecology & Reproductive Sciences, University of Vermont, Burlington, Vermont
| | - Joseph E Brayden
- Department of Pharmacology, University of Vermont, Burlington, Vermont; and
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Haase N, Rugor J, Przybyl L, Qadri F, Müller DN, Dechend R. Relaxin does not improve Angiotensin II-induced target-organ damage. PLoS One 2014; 9:e93743. [PMID: 24710077 PMCID: PMC3977876 DOI: 10.1371/journal.pone.0093743] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Accepted: 03/06/2014] [Indexed: 11/23/2022] Open
Abstract
Relaxin is a corpus-luteum produced protein hormone with vasodilatatory, anti-fibrotic, and angiogenic properties that are opposite to angiotensin (Ang) II. We investigated whether or not relaxin ameliorates Ang II-induced target-organ damage. We used double transgenic rats harboring both human renin and angiotensinogen genes (dTGR) that develop severe hypertension, target-organ damage, and die untreated within 7–8 weeks. Recombinant relaxin at a low (26 μg/kg/d) and a high dose (240 μg/kg/d) was given to 4 week-old dTGR and age-matched Sprague-Dawley rats (SD). Systolic blood pressure increased progressively in untreated dTGRs from 162±3 mmHg at week 5 to 225±5 mmHg at week 7. Relaxin had no effect on blood pressure whereas SD rats were normotensive (106±1 mmHg). Untreated and relaxin-treated dTGR had similarly severe cardiac hypertrophy indices. Relaxin did not ameliorate albuminuria and did not prevent matrix-protein deposition in the heart and kidney in dTGR. Finally, relaxin treatment did not reduce mortality. These data suggest that pharmacological doses of relaxin do not reverse severe effects of Ang II.
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Affiliation(s)
- Nadine Haase
- Experimental and Clinical Research Center, a joint cooperation between the Max-Delbrueck Center for Molecular Medicine and the Charité Medical Faculty, Berlin, Germany
| | - Julianna Rugor
- Experimental and Clinical Research Center, a joint cooperation between the Max-Delbrueck Center for Molecular Medicine and the Charité Medical Faculty, Berlin, Germany
| | - Lukasz Przybyl
- Experimental and Clinical Research Center, a joint cooperation between the Max-Delbrueck Center for Molecular Medicine and the Charité Medical Faculty, Berlin, Germany
| | - Fatimunnisa Qadri
- Experimental and Clinical Research Center, a joint cooperation between the Max-Delbrueck Center for Molecular Medicine and the Charité Medical Faculty, Berlin, Germany
| | - Dominik N. Müller
- Experimental and Clinical Research Center, a joint cooperation between the Max-Delbrueck Center for Molecular Medicine and the Charité Medical Faculty, Berlin, Germany
| | - Ralf Dechend
- Experimental and Clinical Research Center, a joint cooperation between the Max-Delbrueck Center for Molecular Medicine and the Charité Medical Faculty, Berlin, Germany
- Department of Cardiology and Nephrology, HELIOS-Klinikum Berlin, Berlin, Germany
- * E-mail:
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Fernández JA, Bankhead P, Zhou H, McGeown JG, Curtis TM. Automated detection and measurement of isolated retinal arterioles by a combination of edge enhancement and cost analysis. PLoS One 2014; 9:e91791. [PMID: 24626349 PMCID: PMC3953588 DOI: 10.1371/journal.pone.0091791] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Accepted: 02/13/2014] [Indexed: 02/04/2023] Open
Abstract
Pressure myography studies have played a crucial role in our understanding of vascular physiology and pathophysiology. Such studies depend upon the reliable measurement of changes in the diameter of isolated vessel segments over time. Although several software packages are available to carry out such measurements on small arteries and veins, no such software exists to study smaller vessels (<50 µm in diameter). We provide here a new, freely available open-source algorithm, MyoTracker, to measure and track changes in the diameter of small isolated retinal arterioles. The program has been developed as an ImageJ plug-in and uses a combination of cost analysis and edge enhancement to detect the vessel walls. In tests performed on a dataset of 102 images, automatic measurements were found to be comparable to those of manual ones. The program was also able to track both fast and slow constrictions and dilations during intraluminal pressure changes and following application of several drugs. Variability in automated measurements during analysis of videos and processing times were also investigated and are reported. MyoTracker is a new software to assist during pressure myography experiments on small isolated retinal arterioles. It provides fast and accurate measurements with low levels of noise and works with both individual images and videos. Although the program was developed to work with small arterioles, it is also capable of tracking the walls of other types of microvessels, including venules and capillaries. It also works well with larger arteries, and therefore may provide an alternative to other packages developed for larger vessels when its features are considered advantageous.
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Affiliation(s)
- José A. Fernández
- Centre for Experimental Medicine, The Queen’s University of Belfast, Belfast, United Kingdom
- * E-mail:
| | - Peter Bankhead
- Centre for Cancer Research and Cell Biology, The Queen’s University of Belfast, Belfast, United Kingdom
| | - Huiyu Zhou
- School of Electronics, Electrical Engineering and Computer Science, The Queen’s University of Belfast, Belfast, United Kingdom
| | - J. Graham McGeown
- Centre for Experimental Medicine, The Queen’s University of Belfast, Belfast, United Kingdom
| | - Tim M. Curtis
- Centre for Experimental Medicine, The Queen’s University of Belfast, Belfast, United Kingdom
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Leo CH, Jelinic M, Parkington HC, Tare M, Parry LJ. Acute intravenous injection of serelaxin (recombinant human relaxin-2) causes rapid and sustained bradykinin-mediated vasorelaxation. J Am Heart Assoc 2014; 3:e000493. [PMID: 24584737 PMCID: PMC3959707 DOI: 10.1161/jaha.113.000493] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Background A recent clinical trial (RELAXin in Acute Heart Failure [RELAX‐AHF]) demonstrated that 48 hours of continuous intravenous infusion of the vasorelaxant peptide serelaxin (recombinant human relaxin‐2) to patients with acute heart failure reduced cardiovascular mortality at 180 days. The persistence of a vasorelaxant response as a potential mechanism for this long‐term benefit and the vascular effects of a bolus intravenous injection of serelaxin have not been examined. This study investigates changes in resistance artery reactivity and passive mechanical wall properties following an intravenous serelaxin injection and whether these vascular effects persist in the absence of detectable circulating serelaxin. Methods and Results Male rats were injected with 13.3 μg/kg serelaxin into the tail vein; mesenteric arteries were assessed 3 and 24 hours after treatment by using wire‐myography. Serelaxin increased basal nitric oxide synthase activity and reduced maximal contraction to endothelin‐1 at 3 hours after administration. Serelaxin treatment also selectively enhanced bradykinin‐mediated endothelium‐dependent relaxation. This effect was sustained for 24 hours in the absence of circulating serelaxin. Serelaxin‐mediated augmentation of bradykinin‐evoked relaxation involved endothelium‐derived hyperpolarization after 3 hours and prostacyclin‐mediated relaxation after 24 hours. Furthermore, upregulation of inducible nitric oxide synthase, phosphorylation of protein kinase B at Ser473 and endothelial nitric oxide synthase at Ser1177 was observed at 24 hours after serelaxin injection. There were no effects of serelaxin on passive arterial wall stiffness. Conclusion Our data show that a bolus intravenous injection of serelaxin modulates endothelial vasodilator function 3 hours after administration, an effect that was sustained for 24 hours. The prolonged bradykinin‐mediated vasorelaxation is principally mediated through prostacyclin.
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Affiliation(s)
- Chen Huei Leo
- Department of Zoology, The University of Melbourne, Parkville, VIC, Australia
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Jelinic M, Leo CH, Post Uiterweer ED, Sandow SL, Gooi JH, Wlodek ME, Conrad KP, Parkington H, Tare M, Parry LJ. Localization of relaxin receptors in arteries and veins, and region-specific increases in compliance and bradykinin-mediated relaxation after in vivo serelaxin treatment. FASEB J 2013; 28:275-87. [PMID: 24036884 DOI: 10.1096/fj.13-233429] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Relaxin is a potent vasodilator of small resistance arteries and modifies arterial compliance in some systemic vascular beds, yet receptors for relaxin, such as RXFP1, have only been localized to vascular smooth muscle. This study first aimed to localize RXFP1 in rat arteries and veins from different organ beds and determine whether receptors are present in endothelial cells. We then tested the hypothesis that region-specific vascular effects of relaxin may be influenced by the cellular localization of RXFP1 within different blood vessels. The aorta, vena cava, mesenteric artery, and vein had significantly higher (P<0.05) RXFP1 immunostaining in endothelial cells compared with vascular smooth muscle, whereas the femoral artery and vein and small pulmonary arteries had higher (P<0.01) RXFP1 immunostaining in the vascular smooth muscle. Male rats were treated subcutaneously with recombinant human relaxin-2 (serelaxin; 4 μg/h) for 5 d; vasodilation and compliance in mesenteric and femoral arteries and veins were compared with placebo controls. Serelaxin significantly (P=0.04) reduced wall stiffness and increased volume compliance in mesenteric arteries but not in the other vessels examined. This was associated with changes in geometrical properties, and not compositional changes in the extracellular matrix. Serelaxin treatment had no effect on acetylcholine-mediated relaxation but significantly (P<0.001) enhanced bradykinin (BK)-mediated relaxation in mesenteric arteries, involving enhanced nitric oxide but not endothelium-derived hyperpolarization or vasodilatory prostanoids. In conclusion, there is differential distribution of RXFP1 on endothelial and smooth muscle across the vasculature. In rats, mesenteric arteries exhibit the greatest functional response to chronic serelaxin treatment.
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Affiliation(s)
- Maria Jelinic
- 2Department of Zoology, The University of Melbourne, Parkville, VIC, 3010, Australia.
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