Renal vascular dysfunction precedes the development of renal damage in the hypertensive Fawn-Hooded rat

2010 ◽  
Vol 298 (3) ◽  
pp. F625-F633 ◽  
Author(s):  
Peter Ochodnický ◽  
Robert H. Henning ◽  
Hendrik J. Buikema ◽  
Dick de Zeeuw ◽  
Abraham P. Provoost ◽  
...  
Keyword(s):  
Renal Damage ◽  
Vascular Dysfunction ◽  
Organ Damage ◽  
Mesenteric Arteries ◽  
Myogenic Tone ◽  
Myogenic Response ◽  
Resistance Arteries ◽  
Renal Vasculature ◽  
End Organ Damage ◽  
Renal Vascular

It is unknown whether generalized vascular dysfunction precedes the development of kidney disease. Therefore, we studied myogenic constriction and endothelium-mediated dilatory responses in two inbred Fawn-Hooded (FH) rat strains, one of which spontaneously develops hypertension, proteinuria, and glomerulosclerosis (FHH), whereas the other (FHL) does not. Small renal, mesenteric resistance arteries and thoracic aorta isolated from FH rats before (7 wk old) and after the development of mild proteinuria (12 wks old) were mounted in perfused and isometric set-ups, respectively. Myogenic response, endothelium-dependent relaxation, and the contribution of endothelium-mediated dilatory compounds were studied using their respective inhibitors. Myogenic reactivity was assessed constructing pressure-diameter curves in the presence and absence of calcium. At the age of 7 wk, renal arteries isolated from kidneys of FHH rats developed significantly lower myogenic tone compared with FHL, most likely because of excessive cyclo-oxygenase 1-mediated production of constrictive prostaglandins. Consequently, young FHH demonstrated reduced maximal myogenic tone (22 ± 4.8 vs. 10.8 ± 2.0%, P = 0.03) and the peak myogenic index (−6.9 ± 4.8 vs. 0.6 ± 0.8%/mmHg, P = 0.07 for FHL vs. FHH, respectively). Active myogenic curves obtained in mesenteric arteries isolated from 7-wk-old rats did not differ between either strain, demonstrating a similar level of systemic myogenic tone in FHL and FHH rats. Therefore, before any renal end-organ damage is present, myogenic response seems selectively impaired in renal vasculature of FHH rats. Aortic reactivity did not differ between FHL and FHH at the time points studied. The present study shows that vascular dysfunction in both small renal and systemic arteries precedes renal end-organ damage in a spontaneous model of hypertension-associated renal damage. These early vascular changes might be potentially involved in the increased susceptibility of FHH rats to renal injury.

scholarly journals Myogenic Vasoconstriction Requires Canonical Gq/11 Signaling of the Angiotensin II Type 1a Receptor in the Murine Vasculature

2020 ◽  
Author(s):  
Yingqiu Cui ◽  
Mario Kassmann ◽  
Sophie Nickel ◽  
Chenglin Zhang ◽  
Natalia Alenina ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Signaling Pathways ◽  
G Protein ◽  
Cerebral Arteries ◽  
Myogenic Tone ◽  
Myogenic Response ◽  
Ang Ii ◽  
Resistance Arteries ◽  
Renal Vasculature ◽  
Downstream Signaling

AbstractBackgroundThe myogenic response is an inherent vasoconstrictive property of resistance arteries to keep blood flow constant in response to increases in intravascular pressure. Angiotensin II (Ang II) type 1 receptors (AT1R) are broadly distributed, mechanoactivated receptors, which have been proposed to transduce myogenic vasoconstriction. However, the AT1R subtype(s) involved and their downstream G protein- and β-arrestin-mediated signaling pathways are still elusive.ObjectiveTo characterize the function of AT1aR and AT1bR in the regulation of the myogenic response of resistance size arteries and possible downstream signaling cascades mediated by Gq/11 and/or β-arrestins.MethodsWe used Agtr1a-/-, Agtr1b-/- and tamoxifen-inducible smooth muscle-specific AT1aR knockout mice (SM-Agtr1a mice). FR900359, [Sar1, Ile4, Ile8] Ang II (SII) and TRV120055 were used as selective Gq/11 protein inhibitor and biased agonists to activate non-canonical β-arrestin and canonical Gq/11 signaling of the AT1R, respectively.ResultsMyogenic and Ang II-induced vasoconstrictions were diminished in the perfused renal vasculature of Agtr1a-/- and SM-Agtr1a mice. Similar results were observed in isolated pressurized mesenteric and cerebral arteries. Myogenic tone and Ang II-induced vasoconstrictions were normal in arteries from Agtr1b-/- mice. The Gq/11 blocker FR900359 decreased myogenic tone and Ang II vasoconstrictions while selective biased targeting of AT1R β-arrestin signaling pathways had no effects.ConclusionThe present study demonstrates that myogenic arterial constriction requires Gq/11-dependent signaling pathways of mechanoactivated AT1aR but not G protein-independent, noncanonical alternative signaling pathways in the murine mesenteric, cerebral and renal circulation.

Abstract P217: Nox Compartmentalization, Protein Oxidation and ER Stress in Vascular Smooth Muscle Cells in Hypertension

Hypertension ◽  
2017 ◽  
Vol 70 (suppl_1) ◽  
Author(s):  
Livia L Camargo ◽  
Augusto C Montezano ◽  
Adam Harvey ◽  
Sofia Tsiropoulou ◽  
Katie Hood ◽  
...  
Keyword(s):  
Er Stress ◽  
Protein Oxidation ◽  
Vascular Function ◽  
Vascular Reactivity ◽  
Stress Proteins ◽  
Vascular Dysfunction ◽  
Mesenteric Arteries ◽  
Resistance Arteries ◽  
Post Translational Modification ◽  
Wistar Kyoto

In hypertension, activation of NADPH oxidases (Noxs) is associated with oxidative stress and vascular dysfunction. The exact role of each isoform in hypertension-associated vascular injury is still unclear. We investigated the compartmentalization of Noxs in VSMC from resistance arteries of Wistar Kyoto (WKY) and spontaneously hypertensive rats (SHR). Expression of Nox1 and Nox4 was increased in SHR cells (96.6±28.7% and 48.2±21.2% vs WKY, p<0.05), as well as basal ROS levels measured by chemiluminescence (110.2±26.4% vs WKY, p<0.05) and amplex red (105.2±33.2% vs WKY, p<0.05). Phosphorylation of unfolded protein response activators, PERK and IRE1α, and expression of ER chaperone BiP were elevated in SHR cells (p<0.05 vs WKY), indicating activation of ER stress response. Immunoblotting after organelle fractionation demonstrated that Noxs are expressed in an organelle-specific manner, with Nox1, 2 and 4 present in plasma membrane, ER and nucleus, but not in mitochondria. In SHR cells, NoxA1ds (Nox1 inhibitor, 10μM) and GKT136901 (Nox1/4 inhibitor, 10μM) decreased AngII-induced ROS levels (p<0.001 vs Ctl). Additionally, mito-tempol (mitochondrial-targeted antioxidant, 50nM) and 4-PBA (ER stress inhibitor, 1mM) decreased basal ROS levels in SHR cells (p<0.05 vs Ctl). Furthermore, oxidation of the antioxidant enzymes Peroxiredoxins (Prx) was increased in SHRSP compared to WKY (2.51±0.14 vs 0.56±0.07, p<0.001). One-dimensional isoelectric focusing revealed that cytosolic Prx2 and mitochondrial Prx3 were more oxidized in SHRSP than WKY cells. Using a biotin-tagged dimedone-based probe (DCP-Bio) we identified oxidation of ER stress proteins BiP and IRE1. To investigate the effect of protein oxidation in vascular function, vascular reactivity was evaluated in isolated mesenteric arteries. Inhibition of general oxidation (DTT 1mM; Emax: 111.7±33.1) and peroxiredoxin (Conoidin A 10nM; Emax: 116.0±7.3) reduces vascular contraction in response to noradrenalin in WKY rats (Emax: 166.6±30.2; p<0.05). These findings suggest an important role for Nox1/4 in redox-dependent organelle dysfunction and post-translational modification of proteins, processes that may play an important role in vascular dysfunction in hypertension.

Abstract 099: Functional Remodeling of the Renal Vasculature Precedes the Establishment of Salt-sensitive Hypertension in Eln-deficient Mice

Hypertension ◽  
2016 ◽  
Vol 68 (suppl_1) ◽  
Author(s):  
Elizabeth A Owens ◽  
Li Jie ◽  
Beverly Reyes ◽  
Elisabeth J Van Bockstaele ◽  
Patrick Osei-Owusu
Keyword(s):  
Blood Pressure ◽  
Structural Damage ◽  
Vascular Dysfunction ◽  
Renal Perfusion ◽  
Dietary Sodium ◽  
Intraluminal Pressure ◽  
Renal Vasculature ◽  
Salt Loading ◽  
Vascular Stiffening ◽  
Renal Vascular

Vascular stiffening due to elastin deficiency is a leading risk for hypertension and chronic kidney disease (CKD). However, the mechanisms by which elastin deficiency is involved in the pathogenesis of hypertension and/or CKD are poorly understood. Here, we used elastin heterozygous mice ( Eln+/- ), an animal model of elastin insufficiency, to test the hypothesis that renal dysfunction due to elastin deficiency occurs independently of and precedes the development of hypertension in this mouse model. We assessed blood pressure (BP) and renal hemodynamics in 30-day (P30) and 12-week old anesthetized male and female mice. At P30, mean blood pressure of Eln+/- was similar to wild type (WT) controls ( Eln+/- , 79 ± 5 vs. WT, 69±3 mmHg, P = 0.06); however, renal blood flow was lower ( Eln+/- 2.9 ± 0.2 vs. WT 4.0 ± 0.5 mL/min/g KW, P = 0.03) whereas renal vascular resistance (RVR; Eln+/- 29 ± 3 vs. WT 18 ± 3 mmHg/mL/min/g KW, P = 0.03) was augmented at baseline in Eln+/- mice. At 12 wks old, RVR remained elevated while filtration fraction was higher in male Eln+/- relative to WT mice ( Eln+/- 44 ± 3 vs. WT 38±5 % P = 0.07). Eln+/- mice showed isolated systolic hypertension that was evident only at nighttime ( Eln+/- 136 ± 2 vs. WT 112 ± 6 mmHg, P <0.01). Acute salt loading with 6% dietary sodium increased daytime systolic blood pressure only in male Eln+/- mice ( Eln+/- 118 ± 5 vs. WT 102 ± 6 mmHg, P = 0.03), causing a rightward shift and blunted slope of the pressure-natriuresis curve. Renal interlobar artery basal tone and myogenic response to increasing intraluminal pressure at P10 were similar ( Eln+/- 78 ± 3 vs. WT 67 ± 6 % P = 0.06) whereas they were augmented at P30 ( Eln+/- 63 ± 4 vs. WT 49 ± 6 % P = 0.05) and at 12 wks old in Eln+/- mice ( Eln+/- 50 ± 2 vs. WT 33 ± 3 % P < 0.01), and normalized by the AT1R blocker, candesartan ( Eln+/- 22 ± 9 vs. WT 8 ± 5 % P = 0.10). We conclude that AT1R mediates augmented mechanotransduction and renal vascular dysfunction due to Eln insufficiency that in turn contribute to altered renal sodium handling and increased BP. Such prolonged systemic BP elevation leads to glomerular structural damage due to high renal perfusion pressure. Therefore, therapies that target the AT1R to control BP in patients with elastin deficiency may be beneficial in preventing hypertension-evoked kidney damage.

Gender differences in myogenic tone in superoxide dismutase knockout mouse: animal model of oxidative stress

2004 ◽  
Vol 287 (1) ◽  
pp. H40-H45 ◽  
Author(s):  
Sukrutha Veerareddy ◽  
Christy-Lynn M. Cooke ◽  
Philip N. Baker ◽  
Sandra T. Davidge
Keyword(s):  
Oxidative Stress ◽  
Vascular Function ◽  
Vascular Tone ◽  
Vascular Dysfunction ◽  
Mesenteric Arteries ◽  
Myogenic Tone ◽  
Intracellular Enzyme ◽  
Male And Female ◽  
Prostaglandin H ◽  
Myogenic Regulation

Oxidative stress mediated by prooxidants has been implicated in the pathogenesis of vascular disorders. However, the effect of prooxidants on myogenic regulation of vascular function and the differential influence of gender is not known. SOD, an intracellular enzyme, restricts excess prooxidant levels and may limit vascular dysfunction. We therefore tested the effects of Cu,Zn SOD deficiency on vascular tone in both male and female SOD knockout (SOD−/−) mice. We hypothesized that myogenic tone would be enhanced in SOD−/− mice by excess prooxidants compared with wild-type control mice. Indeed, resistance-sized mesenteric arteries from SOD−/− mice exhibited enhanced myogenic tone compared with control mice. Myogenic tone was lower in female than male control mice. Interestingly, this gender effect was absent in SOD−/− mice, such that myogenic tone of mesenteric arteries from females was equated to that of arteries from males. Furthermore, the pathways that modulate myogenic tone were diverse. In both male and female control mice, inhibition of prostaglandin H synthase (PGHS) and nitric oxide synthase (NOS) pathways enhanced myogenic tone. In female SOD−/− mice, inhibition of PGHS and NOS pathways enhanced myogenic tone to a greater extent compared with control mice. Conversely, in male SOD−/− mice, NOS and PGHS inhibition did not alter tone and only inhibition of gap junctions enhanced myogenic tone. In conclusion, this study revealed enhanced myogenic tone in SOD−/− mice compared with control mice. Furthermore, Cu,Zn SOD deficiency particularly enhanced myogenic tone in female mice such that their vascular tone attained the level of male SOD−/− mice, possibly mediated by prooxidants.

scholarly journals PC-PLC/sphingomyelin synthase activity plays a central role in the development of myogenic tone in murine resistance arteries

2015 ◽  
Vol 308 (12) ◽  
pp. H1517-H1524 ◽  
Author(s):  
Joseph R. H. Mauban ◽  
Joseph Zacharia ◽  
Seth Fairfax ◽  
Withrow Gil Wier
Keyword(s):  
Specific Inhibitor ◽  
Intrinsic Property ◽  
Tissue Perfusion ◽  
Pressure Control ◽  
Mesenteric Arteries ◽  
Myogenic Tone ◽  
Resistance Arteries ◽  
Virtual Absence ◽  
Sphingomyelin Synthase

Myogenic tone is an intrinsic property of the vasculature that contributes to blood pressure control and tissue perfusion. Earlier investigations assigned a key role in myogenic tone to phospholipase C (PLC) and its products, inositol 1,4,5-trisphosphate (IP3) and diacylglycerol (DAG). Here, we used the PLC inhibitor, U-73122, and two other, specific inhibitors of PLC subtypes (PI-PLC and PC-PLC) to delineate the role of PLC in myogenic tone of pressurized murine mesenteric arteries. U-73122 inhibited depolarization-induced contractions (high external K+ concentration), thus confirming reports of nonspecific actions of U-73122 and its limited utility for studies of myogenic tone. Edelfosine, a specific inhibitor of PI-PLC, did not affect depolarization-induced contractions but modulated myogenic tone. Because PI-PLC produces IP3, we investigated the effect of blocking IP3 receptor-mediated Ca2+ release on myogenic tone. Incubation of arteries with xestospongin C did not affect tone, consistent with the virtual absence of Ca2+ waves in arteries with myogenic tone. D-609, an inhibitor of PC-PLC and sphingomyelin synthase, strongly inhibited myogenic tone and had no effect on depolarization-induced contraction. D-609 appeared to act by lowering cytoplasmic Ca2+ concentration to levels below those that activate contraction. Importantly, incubation of pressurized arteries with a membrane-permeable analog of DAG induced vasoconstriction. The results therefore mandate a reexamination of the signaling pathways activated by the Bayliss mechanism. Our results suggest that PI-PLC and IP3 are not required in maintaining myogenic tone, but DAG, produced by PC-PLC and/or SM synthase, is likely through multiple mechanisms to increase Ca2+ entry and promote vasoconstriction.

scholarly journals Advanced age decreases local calcium signaling in endothelium of mouse mesenteric arteries in vivo

2016 ◽  
Vol 310 (9) ◽  
pp. H1091-H1096 ◽  
Author(s):  
Erika M. Boerman ◽  
Jesse E. Everhart ◽  
Steven S. Segal
Keyword(s):  
Calcium Signaling ◽  
Fluorescent Protein ◽  
Vascular Dysfunction ◽  
Tissue Perfusion ◽  
Mesenteric Arteries ◽  
Advanced Age ◽  
Resistance Arteries ◽  
Internal Elastic Lamina ◽  
Effects Of Aging

Aging is associated with vascular dysfunction that impairs tissue perfusion, physical activity, and the quality of life. Calcium signaling in endothelial cells (ECs) is integral to vasomotor control, exemplified by localized Ca2+ signals within EC projections through holes in the internal elastic lamina (IEL). Within these microdomains, endothelium-derived hyperpolarization is integral to smooth muscle cell (SMC) relaxation via coupling through myoendothelial gap junctions. However, the effects of aging on local EC Ca2+ signals (and thereby signaling between ECs and SMCs) remain unclear, and these events have not been investigated in vivo. Furthermore, it is unknown whether aging affects either the number or the size of IEL holes. In the present study, we tested the hypothesis that local EC Ca2+ signaling is impaired with advanced age along with a reduction in IEL holes. In anesthetized mice expressing a Ca2+-sensitive fluorescent protein (GCaMP2) selectively in ECs, our findings illustrate that for mesenteric arteries controlling splanchnic blood flow the frequency of spontaneous local Ca2+ signals in ECs was reduced by ∼85% in old (24–26 mo) vs. young (3–6 mo) animals. At the same time, the number (and total area) of holes per square millimeter of IEL was reduced by ∼40%. We suggest that diminished signaling between ECs and SMCs contributes to dysfunction of resistance arteries with advanced age. Listen to this article's corresponding podcast at http://ajpheart.podbean.com/e/aging-impairs-endothelial-ca2-signaling/ .

Abstract P620: Aging Decreases Vascular GPER Expression and Function

Hypertension ◽  
2016 ◽  
Vol 68 (suppl_1) ◽  
Author(s):  
Sarah Lindsey ◽  
Jen L Duong ◽  
Margaret A Zimmerman
Keyword(s):  
Estrogen Therapy ◽  
Organ Damage ◽  
Cardiovascular Outcomes ◽  
Mesenteric Arteries ◽  
Rodent Species ◽  
Female Rats ◽  
Resistance Arteries ◽  
Female Population ◽  
Postmenopausal Estrogen ◽  
And Function

Menopause accelerates the development of hypertension, arterial stiffness, end organ damage, and diastolic dysfunction. Postmenopausal hormone therapy relieves menopausal symptoms but promotes adverse cardiovascular outcomes, which may be due to aging-induced alterations in estrogen receptors. We previously published that GPER expression as well as agonist-induced vasorelaxation is decreased in mesenteric arteries from 12 month-old mRen2 female rats. We hypothesized that aging-induced GPER downregulation is present in other rodent species and strains as well. Aortas from young (2-3 months) and aged (11-23 months) C57BL/6 and BALB/c mice were lysed and immunoblotted for GPER protein. In addition, mesenteric arteries from C57BL/6 mice were mounted on a wire myograph and assessed for vasorelaxation in response to estrogen receptor agonists. We found a significant downregulation of GPER in aging aortas (3.1 ± 0.6 vs. 0.63 ± 0.42, P=0.016, N=4 per group). Moreover, we found that vasodilation to the GPER agonist G-1 was significantly attenuated in aging resistance arteries (22 ± 7.5% vs 58 ± 6.5%, P=0.023, N=2-4). Interestingly, vasodilation to the nonselective receptor agonist estradiol was not altered by aging (24 ± 10% vs. 32 ± 2.0%, P=0.23, N=2-4). In light of our previous findings in the rat vasculature, our data indicate that aging-induced decreases in vascular GPER expression and function are conserved across vascular beds and rodent species. We propose that aging-induced GPER downregulation switches the vascular benefits of postmenopausal estrogen therapy from positive to negative. Our future goal is to determine whether therapies that target GPER improve cardiovascular outcomes to protect the aging female population.

Abstract MP31: Peripheral Vascular Dysfunction In A Model Of Small Vessel Disease Of The Brain (CADASIL) Involves Impaired Redox-sensitive Cyclic GMP/PKG Signaling

Hypertension ◽  
2020 ◽  
Vol 76 (Suppl_1) ◽  
Author(s):  
Karla B Neves ◽  
Hannah Morris ◽  
Rheure Alves-lopes ◽  
Augusto C Montezano ◽  
Rhian M Touyz
Keyword(s):  
Soluble Guanylate Cyclase ◽  
Small Vessel Disease ◽  
Vascular Dysfunction ◽  
Plasma Lipid ◽  
Fold Increase ◽  
Mesenteric Arteries ◽  
Small Vessel ◽  
Resistance Arteries ◽  
Vessel Disease ◽  
The Brain

CADASIL, a monogenic condition due to Notch3 mutations, is a very aggressive small vessel disease of the brain resulting in premature vascular dementia and stroke. Changes in cerebral vessels include vascular dysfunction and narrowing, and accumulation of granular osmiophilic material (GOM). It is not clear whether small peripheral arteries undergo similar damage. Therefore, our aim is to assess vascular dysfunction and associated mechanisms in mesenteric resistance arteries from CADASIL mice. Mesenteric arteries (MA) from male CADASIL-causing Notch3 mutation (TgNotch3 R169C ) and wildtype (TgNotch3 WT ) mice (6 months old) were investigated. GOM deposits in MA from CADASIL mice were identified by electron microscopy. mRNA expression of Notch3 (WT: 2.0±0.5 vs. 6.0±1.3) and its downstream target HeyL (WT: 1.1±0.4 vs. 2.9±0.6) was augmented in CADASIL mice (p<0.01), suggesting increased Notch3 activation. CADASIL mice exhibited endothelial-dependent (Emax 109.9±7.4 vs. 81.3±5.4) and -independent dysfunction (pD 2 7.8±0.1 vs. 6.8±0.3); effects associated with increased eNOS inhibition (p-Thr 495 ) (1.8-fold increase) and decreased cGMP levels (1.2±0.2 vs. 0.59±0.2) (p<0.05). Plasma lipid peroxidation (0.8±0.1 vs. 2.0±0.3; p<0.05) and vascular reactive oxygen species (ROS) production (7.2±1.9 vs. 75.4±35.0; p<0.05) were increased in TgNotch3 R169C mice; processes associated with upregulation of soluble guanylate cyclase (sGC) oxidation and decreased sGC activity. H 2 O 2 levels were decreased in TgNotch3 R169C mice (1.9±0.2 vs. 1.1±1.9; p<0.05), which was associated with reduced activation of protein kinase G (PKG). Observations in TgNotch3 R169C mice were recapitulated in human CADASIL, where ROS levels (0.8±0.1 vs. 4.1±2.7; p<0.05) and sGC oxidation were also increased. Our findings demonstrate that the vasculopathy associated with a CADASIL Notch3 gain-of-function mutation in peripheral small vessels involves reduction in eNOS activation and redox-sensitive processes leading to impaired sGC/cGMP signalling pathway. We identify a potential new therapeutic target in CADASIL, for which there are no disease-specific treatments.

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