scholarly journals The Peroxisome Proliferator-Activated Receptor γ Agonist Pioglitazone Protects Vascular Endothelial Function in Hypercholesterolemic Rats by Inhibiting Myeloperoxidase

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Dapeng Zhang ◽  
Yehong Wang ◽  
Ming Yi ◽  
Suli Zhang ◽  
Ye Wu

Objective. Hypercholesterolemia- (HC-) induced endothelial dysfunction is the first step of atherogenesis, and the peroxisome proliferator-activated receptor γ (PPARγ) has been reported to attenuate atherosclerosis formation; however, the underlying mechanisms are not fully understood. The present study was designed to determine whether myeloperoxidase (MPO) mediates HC-induced endothelial dysfunction and the role of the PPARγ agonist pioglitazone (PIO) in attenuating endothelial dysfunction. Methods. Male Wistar rats were fed with normal or high cholesterol diets for 8 weeks. HC rats were randomized to receive dapsone (DDS, the MPO inhibitor) during the last 6 days or PIO for the remaining 4 weeks. Vascular endothelial function was determined by comparing vasorelaxation to ACh, an endothelium-dependent vasodilator, and SNP, an endothelium-independent vasodilator in vascular rings in vitro. The vascular MPO activity, NOx content, and cGMP level were measured by the MPO activity assay kit, NO assay kit, and cGMP RIA kit. Results. Compared with rats fed with normal diet, endothelium-dependent vasodilation, NOx content, and cGMP level were decreased, and MPO activity was increased in thoracic aortas of rats fed with HC diet. There was a negative correlation between vascular endothelial function, NOx content or cGMP level, and MPO activity. PIO obviously reduced the MPO activity, increased NOx content and cGMP level, and improved endothelium-dependent vasodilation function in HC rats, which was essentially the same as that seen with DDS. And, there was a negative correlation between vascular endothelial function, NOx content or cGMP level, and MPO activity in the HC group and the PIO intervention group. Conclusion. MPO might provoke vascular endothelial dysfunction in hypercholesterolemic rats by reducing the NO biological activity and impairing the NO/cGMP/cGK signaling pathway. PIO might inhibit vascular MPO activity and increase NO bioavailability with the net result of reversing endothelial dysfunction.

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Nadia Calabriso ◽  
Antonio Gnoni ◽  
Eleonora Stanca ◽  
Alessandro Cavallo ◽  
Fabrizio Damiano ◽  
...  

Mitochondria are fundamental organelles producing energy and reactive oxygen species (ROS); their impaired functions play a key role in endothelial dysfunction. Hydroxytyrosol (HT), a well-known olive oil antioxidant, exerts health benefits against vascular diseases by improving endothelial function. However, the HT role in mitochondrial oxidative stress in endothelial dysfunction is not clear yet. To investigate the HT effects on mitochondrial ROS production in the inflamed endothelium, we used an in vitro model of endothelial dysfunction represented by cultured endothelial cells, challenged with phorbol myristate acetate (PMA), an inflammatory, prooxidant, and proangiogenic agent. We found that the pretreatment of endothelial cells with HT (1–30 μmol/L) suppressed inflammatory angiogenesis, a crucial aspect of endothelial dysfunction. The HT inhibitory effect is related to reduced mitochondrial superoxide production and lipid peroxidation and to increased superoxide dismutase activity. HT, in a concentration-dependent manner, improved endothelial mitochondrial function by reverting the PMA-induced reduction of mitochondrial membrane potential, ATP synthesis, and ATP5β expression. In PMA-challenged endothelial cells, HT also promoted mitochondrial biogenesis through increased mitochondrial DNA content and expression of peroxisome proliferator-activated receptor gamma coactivator 1-alpha, nuclear respiratory factor-1, and mitochondrial transcription factor A. These results highlight that HT blunts endothelial dysfunction and pathological angiogenesis by ameliorating mitochondrial function, thus suggesting HT as a potential mitochondria-targeting antioxidant in the inflamed endothelium.


2020 ◽  
Vol 127 (Suppl_1) ◽  
Author(s):  
Poonam Rao ◽  
Pooneh Nabavizadeh Rafsanjani ◽  
Daniel Han ◽  
Suzaynn Schick ◽  
Matthew Springer

Introduction: Exposure to tobacco and marijuana smoke impairs vascular endothelial function. While the particulate phase of smoke is heavily implicated, the role of volatile constituents is unclear. Smoke contains aldehydes, which are known to cause endothelial dysfunction. We explored whether two aldehydes found in smoke, acrolein and acetaldehyde, can induce endothelial dysfunction. Hypothesis: Aldehydes in smoke impair endothelial function. Methods: We exposed 4 groups of anesthetized rats to 3 ppm acrolein and 10-11.5 ppm acetaldehyde gases (concentrations relevant to levels in secondhand smoke), Marlboro Red cigarette sidestream smoke at modest levels (600 μg/m 3 PM2.5) as a positive control, and clean air through the gas generation system as a negative control. Exposure was continuous for 10 minutes. Endothelial function (flow-mediated dilation; FMD) was quantified pre- and post-exposure by measuring femoral artery diameter with ultrasound before and after 5 min of transient ischemia and expressed as % vasodilation. Results: Impairment of FMD was observed for acrolein (10.8±1.7(SD)% vs. 5.8±2.9%, p=.001), acetaldehyde (8.8±2.0% vs. 6.0±2.5%, p=.001), and cigarette smoke (9.4±2.9% vs. 5.8±2.0%, p=.002), but not for air (7.9±2.0% vs. 9±3.2%, p=.44) (figure; each colored line denotes a rat pre- and post-exposure; bars denote means). Conclusions: Acrolein and acetaldehyde at levels found in secondhand smoke impair endothelial function. Our results suggest that despite a potential role of particles, volatile aldehydes may mediate part of the endothelial dysfunction caused by exposure to smoke.


2016 ◽  
Vol 44 (07) ◽  
pp. 1393-1412 ◽  
Author(s):  
Qianqian Dong ◽  
Wenjuan Xing ◽  
Feng Fu ◽  
Zhenghua Liu ◽  
Jie Wang ◽  
...  

Autophagy exists in vascular endothelial cells, but the relationship between autophagy and blood vessel dysfunction in hypertension remains elusive. This study aimed to investigate role of autophagy in vascular endothelial dysfunction in prehypertension and hypertension and the underlying mechanisms involved. Furthermore, we sought to determine if and how tetrahydroxystilbene glucoside (TSG), a resveratrol analogue and active ingredient of Polygonum multiflorum Thunb used for its cardiovascular protective properties in traditional Chinese medicine, influences vascular endothelial function. Male spontaneously hypertensive rats (SHRs) aged 4 weeks (young) and 12 weeks (adult) were studied and the vascular function of isolated aorta and mesenteric artery was assessed in vitro. Compared with Wistar Kyoto rats (WKY), young and adult SHRs showed endothelial dysfunction of the aorta and mesenteric artery, along with decreased pAkt, pmTOR, and autophagic marker protein p62 and increased LC3 II/I in microvascular but not aortic tissues. TSG administration for 14 days significantly improved mesenteric vascular endothelial function, increased levels of pAkt and pmTOR, and decreased autophagy. Pretreatment of young SHRs with the mTOR inhibitor rapamycin blocked the antiautophagic and vasodilative effects of TSG. Moreover, TSG significantly activated Akt-mTOR signaling in HUVECs and reduced the autophagic levels in vitro, which were almost completely blocked by rapamycin. In summary, mesenteric endothelial dysfunction in prehypertensive SHRs was at least partly attributable to excessive autophagy in vascular tissues. TSG partly restored microvascular endothelial dysfunction through activating the Akt/mTOR pathway, which consequently suppressed autophagy, indicating that TSG could be potentially applied to protect vascular function against subclinical changes in prehypertension.


2016 ◽  
Vol 310 (11) ◽  
pp. L1233-L1242 ◽  
Author(s):  
Jia-Xin Ye ◽  
Shan-Shan Wang ◽  
Min Ge ◽  
Dong-Jin Wang

Endothelial dysfunction plays a principal role in the pathogenesis of pulmonary arterial hypertension (PAH), which is a fatal disease with limited effective clinical treatments. Mitochondrial dysregulation and oxidative stress are involved in endothelial dysfunction. Peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) is a key regulator of cellular energy metabolism and a master regulator of mitochondrial biogenesis. However, the roles of PGC-1α in hypoxia-induced endothelial dysfunction are not completely understood. We hypothesized that hypoxia reduces PGC-1α expression and leads to endothelial dysfunction in hypoxia-induced PAH. We confirmed that hypoxia has a negative impact on endothelial PGC-1α in experimental PAH in vitro and in vivo. Hypoxia-induced PGC-1α inhibited the oxidative metabolism and mitochondrial function, whereas sustained PGC-1α decreased reactive oxygen species (ROS) formation, mitochondrial swelling, and NF-κB activation and increased ATP formation and endothelial nitric oxide synthase (eNOS) phosphorylation. Furthermore, hypoxia-induced changes in the mean pulmonary arterial pressure and right heart hypertrophy were nearly normal after intervention. These results suggest that PGC-1α is associated with endothelial function in hypoxia-induced PAH and that improved endothelial function is associated with improved cellular mitochondrial respiration, reduced inflammation and oxygen stress, and increased PGC-1α expression. Taken together, these findings indicate that PGC-1α may be a new therapeutic target in PAH.


2017 ◽  
Vol 313 (5) ◽  
pp. H890-H895 ◽  
Author(s):  
Matthew J. Rossman ◽  
Rachelle E. Kaplon ◽  
Sierra D. Hill ◽  
Molly N. McNamara ◽  
Jessica R. Santos-Parker ◽  
...  

Cellular senescence is emerging as a key mechanism of age-related vascular endothelial dysfunction, but evidence in healthy humans is lacking. Moreover, the influence of lifestyle factors such as habitual exercise on endothelial cell (EC) senescence is unknown. We tested the hypothesis that EC senescence increases with sedentary, but not physically active, aging and is associated with vascular endothelial dysfunction. Protein expression (quantitative immunofluorescence) of p53, a transcription factor related to increased cellular senescence, and the cyclin-dependent kinase inhibitors p21 and p16 were 116%, 119%, and 128% greater (all P < 0.05), respectively, in ECs obtained from antecubital veins of older sedentary (60 ± 1 yr, n = 12) versus young sedentary (22 ± 1 yr, n = 9) adults. These age-related differences were not present (all P > 0.05) in venous ECs from older exercising adults (57 ± 1 yr, n = 13). Furthermore, venous EC protein levels of p53 ( r = −0.49, P = 0.003), p21 ( r = −0.38, P = 0.03), and p16 ( r = −0.58, P = 0.002) were inversely associated with vascular endothelial function (brachial artery flow-mediated dilation). Similarly, protein expression of p53 and p21 was 26% and 23% higher (both P < 0.05), respectively, in ECs sampled from brachial arteries of healthy older sedentary (63 ± 1 yr, n = 18) versus young sedentary (25 ± 1 yr, n = 9) adults; age-related changes in arterial EC p53 and p21 expression were not observed ( P > 0.05) in older habitually exercising adults (59 ± 1 yr, n = 14). These data indicate that EC senescence is associated with sedentary aging and is linked to endothelial dysfunction. Moreover, these data suggest that prevention of EC senescence may be one mechanism by which aerobic exercise protects against endothelial dysfunction with age. NEW & NOTEWORTHY Our study provides novel evidence in humans of increased endothelial cell senescence with sedentary aging, which is associated with impaired vascular endothelial function. Furthermore, our data suggest an absence of age-related increases in endothelial cell senescence in older exercising adults, which is linked with preserved vascular endothelial function. Listen to this article's corresponding podcast at http://ajpheart.podbean.com/e/aging-exercise-and-endothelial-cell-senescence/ .


Medicina ◽  
2021 ◽  
Vol 57 (10) ◽  
pp. 1008
Author(s):  
Shuhei Tanaka ◽  
Teruhiko Imamura ◽  
Ryuichi Ushijima ◽  
Mitsuo Sobajima ◽  
Nobuyuki Fukuda ◽  
...  

Background and objectives: Endothelial dysfunction is associated with exercise intolerance and adverse cardiovascular events. Transcatheter aortic valve implantation (TAVI) is applied to treat elderly patients with severe aortic stenosis, but less is known about the impact of TAVI on endothelial dysfunction, which can be assessed by measuring flow-mediated vasodilation (FMD). In this parameter, a low value indicates impaired endothelial function. Materials and Methods: Vascular endothelial function was evaluated by FMD of the brachial artery just before and one week after TAVI. Factors associated with the normalization of FMD and their prognostic impact were investigated. Results: Fifty-one patients who underwent TAVI procedure (median 86 years old, 12 men) were included. FMD improved significantly from baseline to one week following TAVI (from 5.3% [3.7%, 6.7%] to 6.3% [4.7%, 8.1%], p < 0.001). Among 33 patients with baseline low FMD (≤6.0%), FMD normalized up to >6.0% following TAVI in 15 patients. Baseline higher cardiac index was independently associated with normalization of FMD following TAVI (odds ratio 11.8, 95% confidence interval 1.12–124; p < 0.04). Conclusions: Endothelial dysfunction improved following TAVI in many patients with severe aortic stenosis. The implication of this finding is the next concern.


Hypertension ◽  
2016 ◽  
Vol 68 (suppl_1) ◽  
Author(s):  
John J Reho ◽  
Deng-Fu Guo ◽  
Andrew Olson ◽  
Lauren Wegman-Points ◽  
Isaac Samuel ◽  
...  

Obesity-induced hypertension is associated with vascular endothelial dysfunction. Recently, our laboratory has demonstrated a critical role of the mammalian target of rapamycin complex 1 (mTORC1) signaling pathway in cardiovascular regulation. Here, we tested the hypothesis that dysregulation of mTORC1 signaling is involved in the endothelial dysfunction associated with obesity in mice and humans. We found that diet-induced obese (DIO) mice that display vascular endothelial dysfunction as compared to lean controls have increased mTORC1 signaling in aortic lysates indicated by the elevated (p<0.05) phosphorylated levels of mTOR and its downstream signaling targets S6-kinase and the ribosomal S6 protein measured by Western blot. Increased vascular mTORC1 signaling in DIO mice was associated with increased aortic NOX2 mRNA expression (2.0±0.2 vs. 1.0±0.3AU in lean controls; p<0.05). Isolated abdominal subcutaneous adipose arterioles from non-diabetic obese (BMI ≥30 kg/m 2 ; n=4; age 51±6 yrs; BMI 54±3 kg/m 2 ) humans exhibited a strong trend towards increased phosphorylated S6 protein compared to normal-weight (BMI <30kg/m 2 ; n=3; age 44±15 yrs; BMI 26±1 kg/m 2 ) individuals (5.0±1.9 vs 0.8±0.4AU; p=0.12), suggesting increased vascular mTORC1 signaling in human obesity. Next, we used an adenoviral construct of a constitutively active (CA) S6-kinase (Ad-CAS6K) to enhance mTORC1 signaling. In mouse endothelial cells, Ad-CAS6K increased mRNA expression of oxidative stress (NOX1and NOX2) and inflammatory markers (IL-1β) and decreased endothelial NOS expression (p<0.05). Transfection of aortic rings with the Ad-CAS6K resulted in impairment in acetylcholine-induced relaxation (Max. relaxation: 67± 5 vs. 81 ±3%; p<0.05) without altering the relaxation evoked by sodium nitroprusside (Max. relaxation: 90±1% vs. 90±2%) recapitulating the vascular phenotype in obese mice. Taken together, our data demonstrate a novel role of the mTORC1 signaling pathway in the regulation of vascular endothelial function. Our data also implicate dysregulation of the endothelial mTORC1 signaling pathway in the endothelial dysfunction associated with obesity.


Hypertension ◽  
2015 ◽  
Vol 66 (suppl_1) ◽  
Author(s):  
Gary L Pierce ◽  
Donna A Santillan ◽  
Diedre Fleener ◽  
Sabrina M Scroggins ◽  
Kimberlly K Leslie ◽  
...  

Circulating copeptin, a stable biomarker of vasopressin (AVP) secretion, is elevated throughout pregnancy in women who develop preeclampsia (PreE) and is a strong predictor of PreE as early as the 6th week gestation. Reduced vascular endothelial function and increased aortic stiffness occur in mid-gestation before clinical signs/symptoms of PreE manifest, suggesting that maternal vascular dysfunction may be an early event in the pathogenesis of PreE. However, it is unknown whether elevated copeptin/AVP in early/mid gestation contributes to vascular dysfunction in pregnant women who subsequently develop PreE. Therefore, we hypothesized that elevated copeptin would be associated with increased aortic stiffness and reduced vascular endothelial function in early/mid gestation of pregnant women at high risk for PreE. Pregnant women in the 1st trimester (n=72; age=30 ±1 yrs; BMI=34 ± 1 kg/m2) with at least 1 risk factor for PreE were enrolled. Aortic stiffness (carotid-femoral pulse wave velocity, CFPWV), vascular endothelial function (brachial artery flow-mediated dilation, FMD), blood pressure (BP) and plasma copeptin (ELISA) were assessed in both the 1st (11.7 ± 0.2 wks) and 2nd (18.8 ± 0.4 wks) trimesters. In the 1st trimester, CFPWV (7.3 ± 0.2 vs. 7.3 ± 0.5 m/sec, P=0.86), brachial artery FMD (12.9 ± 1.1 vs. 14.3 ± 2.0%, P=0.53), BP, BMI and age did not differ between women in the highest (1513 ± 221 pg/ml) vs. lowest (279 ± 12 pg/ml) quartile of copeptin (P<0.01). In contrast, 2nd trimester CFPWV was greater (7.2 ± 0.2 vs. 6.4 ± 0.2 m/sec, P<0.05) and brachial artery FMD was lower (10.2 ± 2.8 vs. 16.5 ± 1.3 %, P<0.05) among women in the highest (1714 ± 481 pg/ml) vs. the lowest (249 ± 13 pg/ml) quartile of copeptin (P<0.01), in the absence of differences in BP, BMI or age. For the entire cohort, (log)copeptin was significantly correlated with CFPWV (r=0.23, P=0.04) and tended to correlate with FMD (r=-0.23, P=0.06) in the 2nd but not in the 1st trimester. These data suggest that elevated copeptin in mid-gestation is associated with aortic stiffness and vascular endothelial dysfunction in pregnant women at high risk for PreE, but whether increased copeptin/AVP causes vascular dysfunction in pregnancies destined for PreE requires further studies using animal models.


2009 ◽  
Vol 297 (5) ◽  
pp. H1647-H1654 ◽  
Author(s):  
Jennifer M. Kleinhenz ◽  
Dean J. Kleinhenz ◽  
Shaojin You ◽  
Jeffrey D. Ritzenthaler ◽  
Jason M. Hansen ◽  
...  

Vascular endothelial cells express the ligand-activated transcription factor, peroxisome proliferator-activated receptor-γ (PPARγ), which participates in the regulation of metabolism, cell proliferation, and inflammation. PPARγ ligands attenuate, whereas the loss of function mutations in PPARγ stimulate, endothelial dysfunction, suggesting that PPARγ may regulate vascular endothelial nitric oxide production. To explore the role of endothelial PPARγ in the regulation of vascular nitric oxide production in vivo, mice expressing Cre recombinase driven by an endothelial-specific promoter were crossed with mice carrying a floxed PPARγ gene to produce endothelial PPARγ null mice (ePPARγ−/−). When compared with littermate controls, ePPARγ−/− animals were hypertensive at baseline and demonstrated comparable increases in systolic blood pressure in response to angiotensin II infusion. When compared with those of control animals, aortic ring relaxation responses to acetylcholine were impaired, whereas relaxation responses to sodium nitroprusside were unaffected in ePPARγ−/− mice. Similarly, intact aortic segments from ePPARγ−/− mice released less nitric oxide than those from controls, whereas endothelial nitric oxide synthase expression was similar in control and ePPARγ−/− aortas. Reduced nitric oxide production in ePPARγ−/− aortas was associated with an increase in the parameters of oxidative stress in the blood and the activation of nuclear factor-κB in aortic homogenates. These findings demonstrate that endothelial PPARγ regulates vascular nitric oxide production and that the disruption of endothelial PPARγ contributes to endothelial dysfunction in vivo.


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