Abstract 060: Role of Mir-214 in the Regulation of Perivascular Fibrosis in Angiotensin II Induced Hypertension

Hypertension ◽  
2017 ◽  
Vol 70 (suppl_1) ◽  
Author(s):  
Ryszard Nosalski ◽  
Mateusz Siedlinski ◽  
Aurelie Nguyen Dinh Cat ◽  
Dominik Skiba ◽  
Eilidh Mcginnigle ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
T Cells ◽  
Angiotensin Ii ◽  
Mrna Expression ◽  
Vascular Function ◽  
Gene Expression Regulation ◽  
Mesenteric Arteries ◽  
Control Group ◽  
Regulation Mechanism ◽  
Perivascular Inflammation

Objective: Hypertension (HT) is associated with perivascular inflammation and increased vascular fibrosis. MicroRNAs (miR) are a novel gene expression regulation mechanism and play a pivotal role in a range of pathological processes. The role and mechanism of miR214 in vascular fibrosis is unknown. Methods: 3-month-old C57BL/6, miR214KO and wild-type littermates were treated with angiotensin II (AngII, 490ng/kg/min; n=6-10) or control buffer for 14 days. PVATs from C57BL/6 animals were analysed using TaqMan_Rodent_microRNA_Arrays. Histological studies, wire myography, lucigenin-enhanced luminometry and cytometrical analysis was conducted, followed by statistical analysis with ANOVA or t-test. Data are expressed as a mean±SEM. Results: Out of 381 miRs, 16 were significantly overexpressed in C57BL/6 AngII animals, with only miR214 showing 8-fold induction (p<0.01) after Bonferroni correction. Also, 3-fold elevation of pri-miR-214 was observed. Interestingly, hydralazine treatment prevented both these changes (p<0.01). AngII infusion in miR214 KO animals did not alter blood pressure when compared to WT mice. Mir214 KOs exhibited diminished peri-aortic fibrosis (44779±2491 vs 78805±8696μm, p<0.01), upon AngII hypertension. This was associated with a significantly reduced induction of COL1A1, COL3A1 and TGFβ1 mRNA expression in PVAT and aortas (p<0.05). Vascular studies revealed improved endothelial function (69±10 vs. 22±4%, p<0.01), protection against oxidative stress (66±7 vs 118±19 RLU/sec/mg, p<0.001) and NOX2 mRNA expression (1.9±0.2 vs1.1±0.1, p<0.05) in AngII miR-214-KO aortas, while these parameters were not altered in mesenteric arteries. Recruitment of T cells into aortic PVAT was abolished in KO HT animals in comparison to control group (192±65 vs. 603±164 cell/mg; p<0.05). AngII HT was associated with 4-fold increase of miR-214 expression in the circulating peripheral blood T cells and 2-fold in the spleen. Moreover, AngII infusion increased TNFα mRNA expression in WT T cells (1±0.1 vs 1.6±0, p<0.01) whereas this effect was not seen in miR214 KO T cells (0.9±0.3 vs 0.9±0.1). Conclusions: MiR-214 plays a major role in modulation of aortic fibrosis, vascular function, oxidative stress and perivascular inflammation.

scholarly journals A Subpressor Dose of Angiotensin II Elevates Blood Pressure in a Normotensive Rat Model by Oxidative Stress

2015 ◽  
pp. 153-159 ◽  
Author(s):  
M. M. GOVENDER ◽  
A. NADAR
Keyword(s):  
Oxidative Stress ◽  
Blood Pressure ◽  
Angiotensin Ii ◽  
Mrna Expression ◽  
Rat Model ◽  
Wistar Rat ◽  
Control Group ◽  
Sod Activity ◽  
Male Wistar Rats ◽  
Experimental Group

Oxidative stress is an imbalance between free radicals and antioxidants, and is an important etiological factor in the development of hypertension. Recent experimental evidence suggests that subpressor doses of angiotensin II elevate oxidative stress and blood pressure. We aimed to investigate the oxidative stress related mechanism by which a subpressor dose of angiotensin II induces hypertension in a normotensive rat model. Normotensive male Wistar rats were infused with a subpressor dose of angiotensin II for 28 days. The control group was sham operated and infused with saline only. Plasma angiotensin II and H2O2 levels, whole-blood glutathione peroxidase, and AT-1a, Cu/Zn SOD, and p22phox mRNA expression in the aorta was assessed. Systolic and diastolic blood pressures were elevated in the experimental group. There was no change in angiotensin II levels, but a significant increase in AT-1a mRNA expression was found in the experimental group. mRNA expression of p22phox was increased significantly and Cu/Zn SOD decreased significantly in the experimental group. There was no significant change to the H2O2 and GPx levels. Angiotensin II manipulates the free radical-antioxidant balance in the vasculature by selectively increasing O2− production and decreasing SOD activity and causes an oxidative stress induced elevation in blood pressure in the Wistar rat.

scholarly journals Altered vascular contractility in adult female rats with hypertension programmed by prenatal glucocorticoid exposure

2006 ◽  
Vol 188 (3) ◽  
pp. 435-442 ◽  
Author(s):  
P W F Hadoke ◽  
R S Lindsay ◽  
J R Seckl ◽  
B R Walker ◽  
C J Kenyon
Keyword(s):  
Blood Pressure ◽  
Angiotensin Ii ◽  
Adult Female ◽  
Vascular Function ◽  
Mesenteric Arteries ◽  
Female Rats ◽  
Control Group ◽  
Pregnant Rats ◽  
Vascular Contractility

Excessive exposure to glucocorticoids during gestation reduces birth weight and induces permanent hypertension in adulthood. The mechanisms underlying this programmed elevation of blood pressure have not been established. We hypothesised that prenatal glucocorticoid exposure may lead to vascular dysfunction in adulthood. Pregnant rats received dexamethasone (Dex) (100 μg/kg, s.c.) or vehicle (control) daily throughout pregnancy. Blood pressure was elevated (students t-test, unpaired; P < 0.05) in adult female offspring (aged 12–16 weeks) of Dex-treated mothers (148.0 ± 3.6 mmHg, n=10) compared with the control group (138.0 ± 2.5 mmHg, n=8). Vascular responsiveness in aortae and mesenteric arteries was differentially affected by prenatal Dex: aortae were less responsive to angiotensin II, whereas mesenteric arteries were more responsive to norepinephrine, vasopressin and potassium (mesenteric arteries respond poorly to angiotensin II in vitro). Acetylcholine-mediated, endothelium-dependent relaxation was similar in both groups. Prenatal exposure to Dex had no effect on blood pressure or aldosterone response to acute (15 min, i.v.) infusion of angiotensin II (75 ng/kg per min). In contrast, chronic (2-week, s.c.) infusion of angiotensin II (100 ng/kg per min) produced a greater elevation (P < 0.05) of blood pressure in Dex-treated rats (150.0 ± 3.6 mmHg) than in controls (135.3 ± 5.4 mmHg), and aldosterone levels were higher in Dex-treated animals. There was no angiotensin II-induced medial hypertrophy/hyperplasia in mesenteric arteries from Dex-treated rats. These results indicate that vascular function is altered in a region-specific manner in rats with glucocorticoid-programmed hypertension. Despite a striking increase in mesenteric artery contraction in Dex-treated rats, in vivo studies suggest that abnormalities of the renin-angiotensin-aldosterone system, rather than enhanced vascular contractility, may be responsible for the elevation of blood pressure in these animals.

Mediators of mineralocorticoid receptor-induced profibrotic inflammatory responses in the heart

2009 ◽  
Vol 116 (9) ◽  
pp. 731-739 ◽  
Author(s):  
Peter Wilson ◽  
James Morgan ◽  
John W. Funder ◽  
Peter J. Fuller ◽  
Morag J. Young
Keyword(s):  
Oxidative Stress ◽  
Mrna Expression ◽  
Mineralocorticoid Receptor ◽  
Time Course ◽  
Cardiac Fibrosis ◽  
Inflammatory Responses ◽  
Receptor Activation ◽  
Mrna Levels ◽  
Tissue Remodelling ◽  
Perivascular Inflammation

Coronary, vascular and perivascular inflammation in rats following MR (mineralocorticoid receptor) activation plus salt are well-characterized precursors for the appearance of cardiac fibrosis. Endogenous corticosterone, in the presence of the 11βHSD2 (11β hydroxysteroid dehydrogenase type 2) inhibitor CBX (carbenoxolone) plus salt, produces similar inflammatory responses and tissue remodelling via activation of MR. MR-mediated oxidative stress has previously been suggested to account for these responses. In the present study we thus postulated that when 11βHSD2 is inhibited, endogenous corticosterone bound to unprotected MR in the vessel wall may similarly increase early biomarkers of oxidative stress. Uninephrectomized rats received either DOC (deoxycorticosterone), CBX or CBX plus the MR antagonist EPL (eplerenone) together with 0.9% saline to drink for 4, 8 or 16 days. Uninephrectomized rats maintained on 0.9% saline for 8 days served as controls. After 4 days, both DOC and CBX increased both macrophage infiltration and mRNA expression of the p22phox subunit of NADPH oxidase, whereas CBX, but not DOC, increased expression of the NOX2 (gp91phox) subunit. eNOS [endothelial NOS (NO synthase)] mRNA expression significantly decreased from 4 days for both treatments, and iNOS (inducible NOS) mRNA levels increased after 16 days of DOC or CBX; co-administration of EPL inhibited all responses to CBX. The responses characterized over this time course occurred before measurable increases in cardiac hypertrophy or fibrosis. The findings of the present study support the hypothesis that endogenous corticosterone in the presence of CBX can activate vascular MR to produce both inflammatory and oxidative tissue responses well before the onset of fibrosis, that the two MR ligands induce differential but overlapping patterns of gene expression, and that elevation of NOX2 subunit levels does not appear necessary for full expression of MR-mediated inflammatory and fibrogenic responses.

Abstract P074: Mitochondrial Isolevuglandins Contribute To Vascular Oxidative Stress And Mitochondria-targeted Scavenger Of Isolevuglandins Reduces Mitochondrial Dysfunction And Hypertension

Hypertension ◽  
2020 ◽  
Vol 76 (Suppl_1) ◽  
Author(s):  
Anna Dikalova ◽  
Vladimir Mayorov ◽  
Liang Xiao ◽  
Alexander Panov ◽  
Venkataraman Amarnath ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Angiotensin Ii ◽  
Mitochondrial Dysfunction ◽  
Vascular Function ◽  
Therapeutic Potential ◽  
Protein Adducts ◽  
Specific Marker ◽  
Mitochondrial Oxidative Stress ◽  
Major Health Problem ◽  
Multiple Drugs

Hypertension remains a major health problem in Western Societies, and blood pressure is poorly controlled in a third of patients despite use of multiple drugs. Mitochondrial dysfunction contributes to hypertension and mitochondria-targeted agents can potentially improve treatment of hypertension. We have proposed that mitochondrial oxidative stress produces reactive dicarbonyl lipid peroxidation products isolevuglandins (isoLGs) and that scavenging of mitochondrial isoLG improves vascular function and reduces hypertension. To test this hypothesis, we have studied the accumulation of mitochondrial isoLG-protein adducts in human patients with essential hypertension and angiotensin II mouse model of hypertension using mass spectrometry and Western blot analysis. The therapeutic potential of targeting mitochondrial isoLG was tested by the novel mitochondria-targeted isoLG scavenger, mito2HOBA. Mitochondrial isoLG in arterioles isolated from hypertensive patients were 250% greater than in arterioles from normotensive subjects, and ex vivo mito2HOBA treatment of arterioles from hypertensive subjects improved deacetylation of a key mitochondrial antioxidant, superoxide dismutase 2 (SOD2). In human aortic endothelial cells, mito2HOBA diminished mitochondrial superoxide and inhibited cardiolipin oxidation, a specific marker of mitochondrial oxidative stress. In angiotensin II-infused mice, mito2HOBA prevented accumulation of mitochondrial isoLG-protein adducts, improved Sirt3 mitochondrial deacetylase activity, reduced vascular superoxide, increased endothelial nitric oxide, improved endothelium-dependent relaxation, and attenuated hypertension. Mito2HOBA preserved mitochondrial respiration, protected ATP production, and reduced mitochondrial permeability pore opening in angiotensin II-infused mice. These data support the role of mitochondrial isoLGs in endothelial dysfunction and hypertension. We conclude that scavenging of mitochondrial isoLGs may have therapeutic potential in treatment of vascular dysfunction and hypertension.

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 Aerobic exercise training reduces blood pressure, angiotensin II and oxidative stress of patients with resistant hypertension: the EnRiCH trial

2021 ◽  
Vol 42 (Supplement_1) ◽  
Author(s):  
S Lopes ◽  
J Mesquita-Bastos ◽  
M Teixeira ◽  
D Figueiredo ◽  
J Oliveira ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Angiotensin Ii ◽  
Exercise Training ◽  
Aerobic Exercise ◽  
Resistant Hypertension ◽  
Exercise Group ◽  
Aerobic Exercise Training ◽  
Control Group ◽  
Exercise Training Program ◽  
And Oxidative Stress

Abstract Introduction Resistant hypertension is a major challenge of modern cardiovascular medicine, as it is a puzzling problem without a clear solution. Exercise training clearly reduces blood pressure (BP) and oxidative stress in patients with hypertension, however evidence is limited regarding resistant hypertension. Purpose To determine the effect of an aerobic exercise training program in BP, angiotensin II and oxidative stress in patients with resistant hypertension. Methods EnRicH is a prospective, two-center, single-blinded, randomized controlled trial with a parallel two-arm group. Sixty patients with resistant hypertension were randomly assigned in a 1:1 ratio to undergo a 12-week aerobic exercise training program (exercise) or usual care (control). The powered primary efficacy measure was 24-hour ambulatory systolic BP change from baseline. Secondary outcome measures included daytime and nighttime ambulatory BP, office BP, cardiorespiratory fitness, and oxidative stress and inflammatory biomarkers: Interferon-gamma (IFN-y), Angiotensin II, vascular endothelial growth factor (VEGF), and superoxide dismutase (SOD). Results Fifty-three patients (exercise n=26, control n=27) completed the study. Patients were mainly women (54.7%), with an office BP of 140.7±15.9/84.2±9.4 mm Hg and taking an average of 4.6 antihypertensive medications (median, 5; range, 3 to 7). At baseline, no differences were found between groups for the study outcomes and patient characteristics. Ambulatory systolic BP was reduced −7.1 mm Hg (95% CI, −12.8 to −1.4; P=0.015) in the exercise group (127.4±12.2 to 121.2±12.2, p=0.007) compared to control group (126.1±17.2 to 126.9±15.2, p=514) over 24-hour. In addition, 24-hour ambulatory diastolic BP (−5.1 mm Hg, −7.9 to −2.3, P=0.001), daytime ambulatory systolic (−8.4 mm Hg, −14.3 to −2.5, P=0.006), and diastolic BP (−5.7 mm Hg, −9.0 to −2.4, P=0.001) were also reduced in the exercise group compared to the control group. There were no differences in the change of nighttime ambulatory BP between groups. Cardiorespiratory fitness improved in the exercise group by 14% (4.7 ml.kg-1.min-1, P&lt;0.001), while it remained unchanged in the control group (−0.37 ml.kg-1.min-1, P=0.442). A significant between-group difference in favor of exercise group was found for IFN-y (−4.3 pg/mL, 95% CI: −7.1 to −1.5; P=0.003), Angiotensin II (−157.0 pg/mL, 95% CI: −288.1 to −25.9; P=0.020), VEGF (10.53 pg/mL, 95% CI: 0.60 to 22.54; P=0.035), and SOD (0.35 pg/mL, 95% CI: 0.10 to 0.58; P=0.009). Conclusions A 12-week moderate intensity aerobic exercise program reduced ambulatory BP, angiotensin II and oxidative stress in patients with resistant hypertension. The antihypertensive effects of exercise in patients with resistant hypertension may be mediated by positive changes in oxidative stress and inflammatory biomarkers. FUNDunding Acknowledgement Type of funding sources: Foundation. Main funding source(s): European Union through European Regional Development Fund – Operational Competitiveness Factors Program (COMPETE)Portuguese Government through FCT - Foundation for Science and Technology

scholarly journals Renal impairment induced by prenatal exposure to angiotensin II in male rat offspring

2019 ◽  
Vol 244 (11) ◽  
pp. 923-931 ◽  
Author(s):  
Pavel Svitok ◽  
Monika Okuliarova ◽  
Ivan Varga ◽  
Michal Zeman
Keyword(s):  
Oxidative Stress ◽  
T Cells ◽  
Angiotensin Ii ◽  
Immune Cells ◽  
Brush Border ◽  
Mature Male ◽  
Proximal Tubules ◽  
Female Rats ◽  
Ang Ii ◽  
Prenatally Exposed

Suboptimal conditions during prenatal ontogeny can impair development of several physiological systems and result in cardiometabolic diseases in adulthood. The kidney has been identified as one of the most sensitive organs for developmental programming, but underlying mechanisms are not fully understood. Therefore, in our study we explored the consequences of prenatally increased angiotensin II (Ang II) on the structural development of the kidney and its damage by infiltrated immune cells under normal diet and after an increased salt intake, as a second insult representing a lifestyle factor in humans. Female rats were implanted with osmotic mini-pumps continuously releasing Ang II of dose 2 µg/kg/h during last two weeks of pregnancy, whereas control females were sham operated. Immunohistological and ultrastructural evaluations of the kidneys and their infiltration with immune cells were performed in mature male progeny kept either on a standard or increased salt (2% NaCl) diet. Glomerular volume decreased and the cortical tubulointerstitial injury increased in the offspring prenatally exposed to Ang II with no additional effect of increased salt. Ultrastructural examination demonstrated degenerative changes in proximal tubules, mainly fewer and shorter microvilli in the brush border, enlarged mitochondria, and an increased number of lysosomes in the epithelial cells in the progeny prenatally exposed to Ang II. Moreover, the treatment resulted in increased infiltration of T-cells and macrophages in the renal cortex compared to controls. These changes paralleled with reduced numbers of cytotoxic T-cells in circulation and higher oxidative burst of neutrophils in the progeny of Ang II-treated mothers compared to controls. Altogether, results suggest that prenatally increased Ang II promoted infiltration of immune cells in the kidney and subsequent oxidative stress, which induced a damage of renal glomerular and tubular system entailing negative consequences on the cardiovascular system. Impact statement Suboptimal prenatal conditions can contribute to development of cardiovascular diseases and an altered renin-angiotensin-aldosterone system (RAAS) can be involved in the process. In our study, increased angiotensin II in pregnant female rats resulted in renal cortical interstitial damage, and renal ultrastructural changes in the glomeruli, the brush border of proximal tubules and mitochondria in mature male offspring. The treatment promoted infiltration of T cells and macrophages in the kidneys and primed an oxidative burst of circulating neutrophils, indicating a pro-inflammatory state in the progeny of angiotensin II-treated mothers. Deregulated RAAS of mothers is involved in developmental programming of hypertension in adult male offspring via damaging kidney morphology and function. These findings suggest that preventing the activation of RAAS and oxidative stress during perinatal development might protect against hypertension development in adult male progeny.

Crocin treatment decreased pancreatic atrophy, LOX-1 and RAGE mRNA expression of pancreas tissue in cholesterol-fed and streptozotocin-induced diabetic rats

2019 ◽  
Vol 17 (2) ◽  
Author(s):  
Mohammad Ehsan Bayatpoor ◽  
Saeed Mirzaee ◽  
Mohammad Karami Abd ◽  
Mohammad Taghi Mohammadi ◽  
Shima Shahyad ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Mrna Expression ◽  
Tissue Damage ◽  
Critical Role ◽  
Serum Glucose ◽  
Diabetic Rats ◽  
Control Treatment ◽  
Pcr Analysis ◽  
Control Group ◽  
Cholesterol Levels

AbstractObjectiveOxidative stress in diabetic mellitus is a consequence of oxidative stress, which plays a critical role in the pathogenesis of diabetic tissue damage. Receptors for advanced glycation end products and for oxidized low-density lipoproteins (LDL) have critical contribution in oxidative tissue damage. The present study investigated whether anti-diabetic effects of Crocin via modulation of mRNA expression of RAGE and LOX-1 receptors in diabetic rats.MethodsIn the current study, high-fat cholesterol (HFC) and streptozotocin (40 mg/kg) used to induce type II diabetes. Experimental groups as follows: (Group 1: control); (Group 2: control treatment [Crocin]); (Group 3: DM [STZ]); (Group 4: DM treatment [STZ + Crocin]); (Group 5; DM + HFC [STZ + HFC]); (Group 6; DM + HFC treatment [STZ + HFC + Crocin]). Crocin (20 mg/kg/day, i.p.) administered in treatment groups for 60 days. Serum glucose and cholesterol levels evaluated on days 5, 30 and 60 after induction of DM. Pancreatic tissue from all group removed on day 60 for histological and RT-PCR analysis.ResultsApplication of Crocin significantly decreased serum cholesterol levels on day 60 after induction of DM in diabetic + HFC rats. Moreover, Crocin significantly decreased serum glucose levels on days 30 and 60 both in diabetic and diabetic + HFC rats. Crocin partially prevented the atrophic effects of STZ on both exocrine and endocrine parts of pancreas. Additionally, Crocin significantly decreased LOX-1 and RAGE mRNA expression OF pancreas in diabetic rats.ConclusionThe current study suggested that Crocin suppressed atrophic change of the pancreas by decrease of LOX-1 and RAGE mRNA expression in diabetic rats.

scholarly journals Hypoxia-reoxygenation enhances murine afferent arteriolar vasoconstriction by angiotensin II

2018 ◽  
Vol 314 (3) ◽  
pp. F430-F438 ◽  
Author(s):  
Tamara Pahlitzsch ◽  
Zhi Zhao Liu ◽  
Amira Al-Masri ◽  
Diana Braun ◽  
Stefanie Dietze ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Mrna Expression ◽  
Vascular Function ◽  
Calcium Transients ◽  
Surrounding Tissue ◽  
Ang Ii ◽  
Sod Activity ◽  
Afferent Arterioles ◽  
The Impact ◽  
Hypoxia Reoxygenation

We tested the hypothesis that hypoxia-reoxygenation (H/R) augments vasoreactivity to angiotensin II (ANG II). In particular, we compared an in situ live kidney slice model with isolated afferent arterioles (C57Bl6 mice) to assess the impact of tubules on microvessel response. Hematoxylin and eosin staining was used to estimate slice viability. Arterioles in the slices were located by differential interference contrast microscopy, and responses to vasoactive substances were assessed. Cytosolic calcium transients and NADPH oxidase (NOX) mRNA expression were studied in isolated afferent arterioles. SOD activity was measured in live slices. Both experimental models were subjected to control and H/R treatment (60 min). Slices were further analyzed after 30-, 60-, and 90-min hypoxia followed by 10- or 20-min reoxygenation (H/R). H/R resulted in enhanced necrotic tissue damage compared with control conditions. To characterize the slice model, we applied ANG II (10−7 M), norepinephrine (NE; 10−5 M), endothelin-1 (ET-1; 10−7 M), and ATP (10−4 M), reducing the initial diameter to 44.5 ± 2.8, 50.0 ± 2.2, 45.3 ± 2.6, and 74.1 ± 1.8%, respectively. H/R significantly increased the ANG II response compared with control in live slices and in isolated afferent arterioles, although calcium transients remained similar. TEMPOL incubation prevented the H/R effect on ANG II responses. H/R significantly increased NOX2 mRNA expression in isolated arterioles. SOD activity was significantly decreased after H/R. Enhanced arteriolar responses after H/R occurred independently from the surrounding tissue, indicating no influence of tubules on vascular function in this model. The mechanism of increased ANG II response after H/R might be increased oxidative stress and increased calcium sensitivity of the contractile apparatus.

Abstract MP01: Deacetylation Of Mitochondrial Cyclophilin D K166 Inhibits Cytokine-induced Oxidative Stress And Attenuates Hypertension

Hypertension ◽  
2021 ◽  
Vol 78 (Suppl_1) ◽  
Author(s):  
Sergey I Dikalov ◽  
Vladimir Mayorov ◽  
Daniel Fehrenbach ◽  
Mingfang Ao ◽  
Alexander Panov ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Angiotensin Ii ◽  
Vascular Function ◽  
Organ Damage ◽  
Cyclophilin D ◽  
Wild Type ◽  
End Organ Damage ◽  
Mitochondrial Superoxide ◽  
Vascular Oxidative Stress

We have previously reported that depletion Cyclophilin D (CypD), a regulatory subunit of mitochondrial permeability transition pore, improves vascular function and attenuates hypertension, however, specific regulation of CypD in hypertension is not clear. Analysis of human arterioles from hypertensive patients did not reveal alterations in CypD levels but showed 3-fold increase in CypD acetylation. We hypothesized that CypD-K166 acetylation promotes vascular oxidative stress and hypertension, and measures to reduce CypD acetylation can improve vascular function and reduce hypertension. Essential hypertension and animal models of hypertension are linked to inactivation of mitochondrial deacetylase Sirt3 by highly reactive lipid oxidation products, isolevuglandins (isoLGs), and supplementation of mice with mitochondria targeted scavenger of isoLGs, mito2HOBA, improves CypD deacetylation. To test the specific role of CypD-K166 acetylation, we developed CypD-K166R deacetylation mimic mutant mice. Mitochondrial respiration, vascular function and systolic blood pressure in CypD-K166R mice was similar to wild-type C57Bl/6J mice. Meanwhile, angiotensin II-induced hypertension was substantially attenuated in CypD-K166R mice (144 mmHg) compared with wild-type mice (161 mmHg). Angiotensin II infusion in wild-type mice significantly increased mitochondrial superoxide, impaired endothelial dependent relaxation, and reduced the level of endothelial nitric oxide which was prevented in angiotensin II-infused CypD-K166R mice. Hypertension is linked to increased levels of inflammatory cytokines TNFα and IL-17A promoting vascular oxidative stress and end-organ damage. We have tested if CypD-K166R mice are protected from cytokine-induced oxidative stress. Indeed, ex vivo incubation of aorta with the mixture of angiotensin II, TNFα and IL-17A (24 hours) increased mitochondrial superoxide by 2-fold in wild-type aortas which was abrogated in CypD-K166R mice. These data support the pathophysiological role of CypD acetylation in inflammation, oxidative stress and hypertensive end-organ damage. We propose that targeting CypD acetylation may have therapeutic potential in treatment of vascular dysfunction and hypertension.

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