Ginkgolide A attenuates homocysteine-induced endothelial dysfunction in porcine coronary arteries

Activation of nuclear receptor pregnane-X-receptor protects against abdominal aortic aneurysm by inhibiting oxidative stress

Abdominal aortic aneurysm (AAA) is a life-threatening condition, but effective medications to prevent its progression and rupture are currently lacking. The nuclear receptor pregnane-X-receptor (PXR) plays a crucial role in vascular homeostasis. However, the role of PXR in AAA development remains unknown. We first detected the PXR expression in human and murine AAA tissues by RT-qPCR and Western blot. To investigate the potential role of PXR in the development of AAA, we used adeno-associated virus-mediated overexpression of PXR and pharmacological activation of PXR by ginkgolide A (GA) in mouse AAA models induced by both angiotensin II (AngII) and calcium phosphate [Ca3(PO4)2]. The underlying mechanism was further explored using RNA-sequencing and molecular biological analyses. We found a significant decrease in both mRNA and protein levels of PXR in both human and murine aortic smooth muscle cells from AAA tissues, accompanied with phenotypic switching of vascular smooth muscle cell and increased oxidative stress. PXR overexpression in abdominal aortas and GA treatment successfully suppressed AAA formation in both mouse AAA models. RNA-sequencing data revealed that PXR activation inhibited gamma-aminobutyric acid type A receptor subunit alpha3 (GABRA3) expression. Additional mechanistic studies identified that PXR suppressed AAA through mitigating GABRA3-induced reactive oxygen species (ROS) generation and subsequent phosphorylation of c-Jun N-terminal kinase (JNK). Interestingly, p-JNK was found to induce ubiquitin-proteasome degradation of PXR. In summary, our data unveiled, for the first time, the protective role of PXR against AAA pathogenesis by inhibiting oxidative stress. These findings suggested PXR as a promising therapeutic target for AAA.

Ginkgolide A improves the pleiotropic function and reinforces the neuroprotective effects by mesenchymal stem cell-derived exosomes in 6-OHDA-induced cell model of Parkinson's disease

Parkinson's disease (PD) is a common disorder attributed to the loss of midbrain dopamine (mDA) neurons and reduced dopamine secretion. Currently, the treatment regimes for PD comprise deep brain stimulations, however, it attenuates the PD progression marginally and does not improve neuronal cell death. We investigated the function of Ginkgolide A (GA) to reinforce Wharton's Jelly-derived mesenchymal stem cells (WJMSCs) for treating the in vitro model of PD. GA enhanced the self-renewal, proliferation, and cell homing function of WJMSCs as assessed by MTT and transwell co-culture assay with a neuroblastoma cell line. GA pre-treated WJMSCs can restore 6-hydroxydopamine (6-OHDA)-induced cell death in a co-culture assay. Furthermore, exosomes isolated from GA pre-treated WJMSCs significantly rescued 6-OHDA-induced cell death as determined by MTT assay, flow cytometry, and TUNEL assay. Western blotting showed that apoptosis-related proteins were decreased following GA-WJMSCs exosomal treatment which further improved mitochondrial dysfunction. We further demonstrated that exosomes isolated from GA-WJMSCs could restore autophagy using immunofluorescence staining and immunoblotting assay. Finally, we used the alpha-synuclein recombinant protein and found that exosomes derived from GA-WJMSCs led to the reduced aggregation of alpha-synuclein compared to that in control. Our results suggested that GA could be a potential candidate for strengthening stem cell and exosome therapy for PD.

Cardiovascular Activity of Ginkgo biloba-An Insight from Healthy Subjects

Ginkgo biloba is the oldest living tree species in the world. Despite less than encouraging clinical results, extracts from its leaves are among the most used herbal preparations in the prevention and treatment of cardiovascular diseases. Most data on the efficacy of Ginkgo biloba on cardiovascular disease is from clinical studies, with few results from healthy subjects. This paper aims to provide a comprehensive review of the mechanisms underlying the known beneficial cardiovascular activities of Ginkgo biloba. It displays myocardial suppressant and vasorelaxant activities ex vivo, potentiating endothelial-dependent and -independent pathways. It improves perfusion in different vascular beds, namely ocular, cochlear, cutaneous, cerebral, and coronary. Although scarce, evidence suggests that Ginkgo biloba displays a heterogeneous effect on tissue perfusion which is dependent on the individual elimination pathways. It displays an acceptable safety profile, with most reported adverse reactions constituting rare occurrences. Collectively, Ginkgo biloba positively impacts cardiovascular physiology, improving hemodynamics and organ perfusion. In the future, better controlled clinical studies should be performed in order to identify the target populations who may benefit the most from pharmacotherapeutic interventions involving Ginkgo biloba.

Ginkgo biloba extract ameliorates atherosclerosis via rebalancing gut flora and microbial metabolism

The Ginkgo biloba leave extract (GbE) is widely applied in the prevention and treatment of atherosclerotic cardiovascular diseases in clinical practice. However, its mechanism of actions has not been totally elucidated. In this study, we confirmed the beneficial effects of GbE in alleviating hypercholesterolemia, inflammation and atherosclerosis in Ldlr^-/- mice, which were fed 12 weeks of Western diet (WD). Moreover, 16S rRNA sequencing revealed that GbE treatment reshaped the WD-perturbed intestinal microbiota, particularly decreased the Firmicutes/Bacteroidetes ratio and elevated the abundance of Akkermansia, Alloprevotella, Alistipes, and Parabacteroides. Furthermore, GbE treatment downregulated the intestinal transcriptional levels of proinflammatory cytokines and enhanced the expression of tight junction proteins, exerting the roles of attenuating the intestinal inflammation as well as repairing the gut barrier. Meanwhile, the targeted metabolomic analysis displayed that GbE treatment significantly reversed the dysfunction of the microbial metabolic phenotypes, including promoting the production of short chain fatty acids, indole-3-acetate and secondary bile acids, which were correlated with the atherosclerotic plaque areas. Finally, we confirmed GbE-altered gut microbiota was sufficient to alleviate atherosclerosis by fecal microbiota transplantation. In summary, our findings provide important insights into the pharmacological mechanism underlying the antiatherogenic efficacy of GbE.

Herbal Medications Used to Ameliorate Cardiac Conditions

Herbs have been used for centuries to treat various diseases, including cardiovascular disease. Herbs may be used by clients exclusively for disease management or in combination with conventional medications. This article increases provider awareness of certain herbs and their potential use by clients, as well as their impact on the cardiovascular system. It is important for the advanced practice nurse to collect information related to herb use during history retrieval. This information should prompt the nurse to discuss possible benefits and side effects that may occur taking herbs in isolation or in combination with cardiovascular prescription medications.

Gastrodin prevents homocysteine-induced human umbilical vein endothelial cells injury via PI3K/Akt/eNOS and Nrf2/ARE pathway

In this study, we investigated the protective effects of gastrodin (Gas) against homocysteine‐induced human umbilical vein endothelial cell (HUVEC) injury and the role of the phosphoinositide 3‐kinase (PI3K)/threonine kinase 1 (Akt)/endothelial nitric oxide synthase (eNOS) and NF‐E2‐related factor 2 (Nrf2)/antioxidant response element (ARE) pathways. We stimulated cells with homocysteine (1 mmol/L, 24 hours) and tested the effects of gastrodin (200‐800 μg/mL) on cell viability and the production of malondialdehyde (MDA), lactate dehydrogenase (LDH) and reactive oxygen species (ROS). Then, Nrf2 distribution in the cytoplasm and nucleus as well as the expression of enzymes downstream of Nrf2 was determined. Furthermore, we analysed the expression of bax, bcl‐2 and cleaved caspase3, and assessed the involvement of the PI3K/Akt/eNOS pathway by Western blots. Finally, we tested the vasoactive effect of gastrodin in thoracic aortic rings. The results showed that gastrodin decreased MDA, LDH and ROS production and increased cell viability, NO production and relaxation of thoracic aortic rings. Moreover, the protective effects of Gas on NO production and relaxation of thoracic aortic rings were blocked by L‐NAME but enhanced by Cav‐1 knockdown, and MK‐2206 treatment abolished the effect of Gas on the ROS. In addition, treatment with gastrodin increased Nrf2 nuclear translocation, thus enhancing the expression of downstream enzymes. Finally, gastrodin increased the expression of PI3K, p‐Akt, and eNOS and decreased Cav‐1 protein expression. In conclusion, our study suggested that gastrodin may protect HUVECs from homocysteine‐induced injury, and the PI3K/Akt/eNOS and Nrf2/ARE pathways may be responsible for the efficacy of gastrodin.

Therapeutic promises of ginkgolide A: A literature-based review

Ginkgolide A is a highly active platelet activating factor antagonist cage molecule which was isolated from the leaves of the Ginkgo biloba L. It is known for its inflammatory and immunological potentials. This review aims to sketch a current scenario on its therapeutic activities on the basis of scientific reports in the databases. A total 30 articles included in this review suggests that ginkgolide A has many important biological activities, including anti-inflammatory, anticancer, anxiolytic-like, anti-atherosclerosis and anti-atherombosis, neuro- and hepatoprotective effects. There is a lack of its toxicological (e.g. toxicity, cytotoxicity, genotoxicity and mutagenitcity) profile. In conclusion, ginkgolide A may be one of the potential therapeutic lead compounds, especially for the treatment of cardiovascular, hepatological, and neurological diseases and disorders. More studies are necessary on this hopeful therapeutic agent.

Ginkgolide A Prevents the Amyloid-β-Induced Depolarization of Cortical Neurons

Utilizing the N-methyl-d-aspartate (NMDA) receptor antagonist as a strategy, memantine is the only agent available for clinically treating mild to severe Alzheimer's disease (AD). Our aim was to develop novel similar herb-based drugs. Using a screening platform, ginkgolide A (GA), a pure compound extracted from Ginkgo biloba, was found to attenuate amyloid β (Aβ)-induced abnormal depolarization in mouse primary cortical neurons. Using receptor agonists, it was determined that GA inhibits both NMDA receptors and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors. Furthermore, the Aβ-induced increase in c-Jun N-terminal kinase phosphorylation in neurons was prevented by GA. Body weight, glutamate oxaloacetate transaminase, glutamic-pyruvic transaminase, liver histology, and kidney histology were similar when the wild-type/AD animal model mice with and without GA treatment were compared. This pure compound improves the memory of wild-type mice. Our findings indicate that GA has great potential clinically for the treatment of AD because it might target NMDA receptors just like memantine.

Human pharmacokinetics of ginkgo terpene lactones and impact of carboxylation in blood on their platelet-activating factor antagonistic activity

Terpene lactones are a class of bioactive constituents of standardized preparations of Ginkgo biloba leaf extract, extensively used as add-on therapies in patients with ischemic cardiovascular and cerebrovascular diseases. This investigation evaluated human pharmacokinetics of ginkgo terpene lactones and impact of their carboxylation in blood. Human subjects received oral YinXing-TongZhi tablet or intravenous ShuXueNing, two standardized ginkgo preparations. Their plasma protein-binding and platelet-activating factor antagonistic activity were assessed in vitro. Their carboxylation was assessed in phosphate-buffered saline (pH 7.4) and in human plasma. After dosing YinXing-TongZhi tablet, ginkgolides A and B and bilobalide exhibited significantly higher systemic exposure levels than ginkgolides C and J; after dosing ShuXueNing, ginkgolides A, B, C, and J exhibited high exposure levels. The compounds' unbound fractions in plasma were 45-92%. Apparent oral bioavailability of ginkgolides A and B was mostly >100%, while that of ginkgolides C and J was 6-15%. Bilobalide's bioavailability was probably high but lower than that of ginkgolides A/B. Terminal half-lives of ginkgolides A, B, and C (4-7 h) after dosing ShuXueNing were shorter than their respective values (6-13 h) after dosing YinXing-TongZhi tablet. Half-life of bilobalide after dosing the tablet was around 5 h. Terpene lactones were roughly evenly distributed in various body fluids and tissues; glomerular-filtration-based renal excretion was the predominant elimination route for the ginkgolides and a major route for bilobalide. Terpene lactones circulated as trilactones and monocarboxylates. Carboxylation reduced platelet-activating factor antagonistic activity of ginkgolides A, B, and C. Ginkgolide J, bilobalide, and ginkgo flavonoids exhibited no such bioactivity. Collectively, differences in terpene lactones' exposure between the two preparations and influence of their carboxylation in blood should be considered in investigating the relative contributions of terpene lactones to ginkgo preparations' therapeutic effects. The results here will inform rational clinical use of ginkgo preparations.

Ginkgolide A ameliorates non-alcoholic fatty liver diseases on high fat diet mice

Non-alcoholic fatty liver disease (NAFLD) is one of the most common diseases worldwide and has continuously increased. NAFLD refers to a spectrum of diseases ranging from fatty liver to steatohepatitis, cirrhosis, and even to hepatocyte carcinoma. Excessive fatty acid enters the cell and the mitochondria undergo stress and unremoved ROS can trigger a form of cell apoptosis known as 'lipoapoptosis'. NASH arises from damaged liver hepatocytes due to lipotoxicity. NASH not only involves lipid accumulation and apoptosis but also inflammation. Ginkgo biloba has been tested clinical trials as a traditional medicine for asthma, bronchitis and cardiovascular disease. The effects of Ginkgolide A (GA), derived from the ginkgo biloba leaf, are still unknown in NAFLD. To determine the protective effects of GA in NAFLD, we examined the fatty liver disease condition in the non-esterified fatty acid (NEFA)-induced HepG2 cell line and in a high fat diet mouse model. The findings of this study suggest that GA is non-toxic at high concentrations in hepatocytes. Moreover, GA was found to inhibit cellular lipogenesis and lipid accumulation by causing mitochondrial oxidative stress. GA showed hepatoprotective efficacy by inducing cellular lipoapoptosis and by inhibiting cellular inflammation. The results demonstrated that GA may be feasible as a therapeutic agent for NAFLD patients.

Ginkgolide A reduces inflammatory response in high-glucose-stimulated human umbilical vein endothelial cells through STAT3-mediated pathway

High-glucose-induced low-grade inflammation has been regarded as a key event in the onset and progression of endothelial dysfunction in diabetic vascular complications. Ginkgolide A (GA), a major compound from Ginkgo biloba extract, is widely used for the treatment of cardiovascular diseases and diabetic vascular complications. Here, its effect on high-glucose-stimulated vascular inflammation in human umbilical vein endothelial cells (HUVECs) was investigated. In the present study, the optimal stimulation conditions for HUVECs were screened for inducing endothelial inflammation, namely, high glucose at the concentration of 30mM for continuous 8h. The endothelial production of high-glucose-induced interleukin (IL)-4, IL-6, IL-13 and signal transducer and activator of transcription-3 (STAT-3) phosphorylation were significantly inhibited by the pretreatment with GA at concentrations of 10, 15 and 20μM based on enzyme-linked immunosorbent assay (ELISA), western blot or/and RT-PCR experiments. These senescent alterations induced by high glucose were significantly attenuated by the specific STAT3 inhibitor S3I-201 at the concentration of 20μM. Furthermore, the phosphorylation of STAT3, IL-4, IL-6, IL-13 and intercellular cell adhesion molecule-1 (ICAM-1) protein as well as mRNA levels were attenuated by the pretreatment of cells with STAT3 siRNA. Our results demonstrated that GA improved high-glucose-caused low-grade vascular inflammation, which might be achieved through regulating the STAT3-mediated pathway. These findings indicated that GA might be a promising candidate for attenuating vascular inflammation in diabetic vascular complications.

AVE3085 protects coronary endothelium from the impairment of asymmetric dimethylarginine by activation and recoupling of eNOS

PURPOSE

Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of eNOS and it is recognized as a risk factor for endothelial dysfunction in cardiovascular diseases. We investigated the effect of AVE3085, a newly developed transcription enhancer of eNOS, on ADMA-induced endothelial dysfunction in coronary arteries with underlying mechanisms explored.

METHODS

Porcine coronary small arteries (diameter 600-800 μm) were studied in a myograph for endothelium-dependent relaxation to bradykinin and endothelium-independent relaxation to sodium nitroprusside. Protein expressions of eNOS and phosphorylated-eNOS (p-eNOS(Ser1177) and p-eNOS(Thr495)), and nitrotyrosine formation were determined by Western blot. NO release was directly measured with a NO microsensor. Productions of O(2) (.-) and peroxynitrite (ONOO(-)) were determined by lucigenin- and luminol- enhanced chemiluminescence respectively.

RESULTS

Exposure to ADMA significantly decreased the bradykinin-induced vasorelaxation and reduced the protein expression of p-eNOS(Ser1177) whereas increased the expression of p-eNOS(Thr495) and nitrotyrosine. Pre-incubation with AVE3085 restored the bradykinin-induced relaxation, reversed the decrease of p-eNOS(Ser1177), and lowered the level of p-eNOS(Thr495) and nitrotyrosine. NO release in response to bradykinin was significantly reduced by ADMA and such reduction was restored by AVE3085. AVE3085 also prevented the elevation of O (2) (.-) and ONOO(-) levels in coronary arteries exposed to ADMA.

CONCLUSIONS

AVE3085 prevents ADMA-induced endothelial dysfunction in coronary arteries. The protective effect of AVE3085 may be attributed to increased NO production resulting from enhanced eNOS activation, and decreased oxidative stress that involves inhibition of O (2) (.-) generation by eNOS recoupling. The present study suggested the therapeutic potential of AVE3085 in endothelial dysfunction in cardiovascular disorders.

Endothelium dependent expression and underlying mechanisms of des-Arg⁹-bradykinin-induced B₁R-mediated vasoconstriction in rat portal vein

Endothelial dysfunction has been implicated in portal vein obstruction, a condition responsible for major complications in chronic portal hypertension. Increased vascular tone due to disruption of endothelial function has been associated with an imbalance in the equilibrium between endothelium-derived relaxing and contracting factors. Herein, we assessed underlying mechanisms by which expression of bradykinin B(1) receptor (B(1)R) is induced in the endothelium and how its stimulation triggers vasoconstriction in the rat portal vein. Prolonged in vitro incubation of portal vein resulted in time- and endothelium-dependent expression of B(1)R and cyclooxygenase-2 (COX-2). Inhibition of protein kinase C (PKC) or phosphatidylinositol 3-kinase (PI3K) significantly reduced expression of B(1)R through the regulation of transcription factors, activator protein-1 (AP-1) and cAMP response element-binding protein (CREB). Moreover, pharmacological studies showed that B(1)R-mediated portal vein contraction was reduced by COX-2, but not COX-1, inhibitors. Notably, activation of endothelial B(1)R increased phospholipase A(2)/COX-2-derived thromboxane A(2) (TXA(2)) levels, which in turn mediated portal vein contraction through binding to TXA(2) receptors expressed in vascular smooth muscle cells. These results provide novel molecular mechanisms involved in the regulation of B(1)R expression and identify a critical role for the endothelial B(1)R in the modulation of portal vein vascular tone. Our study suggests a potential role for B(1)R antagonists as therapeutic tools for diseases where portal hypertension may be involved.

Nordihydroguaiaretic acid (NDGA) inhibits ritonavir-induced endothelial dysfunction in porcine pulmonary arteries

BACKGROUND

HIV infection and treatment with highly active antiretroviral therapy (HAART) including HIV protease inhibitor ritonavir (RTV) have been associated with endothelial dysfunction and cardiovascular disease including pulmonary arterial hypertension. The objective of this study was to determine if nordihydroguaiaretic acid (NDGA), a natural herbal antioxidant found in the creosote bush Larrea tridentate, can protect vascular tissues against RTV-induced vascular injury.

MATERIAL/METHODS

Fresh porcine pulmonary artery (PA) rings were treated with a clinically relevant concentration of RTV (15 µmol/L) with or without NDGA for 24 hours, and then subjected to myograph analysis for vasomotor reactivity. Expression of endothelial nitric oxide synthase (eNOS) in both treated PA rings and human pulmonary artery endothelial cells (HPAECs) was analyzed by real-time PCR and immunohistochemistry. Oxidative stress levels were analyzed with the lucigenin-enhanced chemiluminescence and glutathione assay.

RESULTS

In response to bradykinin at 10-10 mol/L, RTV-treated PA rings showed a 39% reduction in endothelium-dependent vasorelaxation compared with the control vessels (P<0.05); when co-cultured with NDGA (1.75 or 3.50 µmol/L), the relaxation increased by 25% and 48%, respectively. RTV also decreased the maximal contraction and endothelium-independent vasorelaxation in RTV-treated vessels, while NDGA improved these vasomotor responses. In addition, treatment of RTV significantly decreased eNOS mRNA levels in both porcine PAs and HPAECs, and reduced eNOS immunoreactivity in porcine PAs, while NDGA significantly inhibited this effect of RTV. Furthermore, NDGA significantly blocked RTV-induced increase of superoxide anion in the PA rings and inhibited RTV-induced decrease of glutathione in HPAECs.

CONCLUSIONS

NDGA effectively inhibits the detrimental effects of HIV protease inhibitor RTV on vasomotor functions in porcine PAs. NDGA also blocks RTV-induced decrease of eNOS expression and increase of oxidative stress in both porcine PAs and HPAECs. This study may provide valuable information for the development of effective strategies for the prevention and treatment of HAART-associated cardiovascular complications.

Natural antioxidant dihydroxybenzyl alcohol blocks ritonavir-induced endothelial dysfunction in porcine pulmonary arteries and human endothelial cells

Background

Patients with HIV have an increased incidence of pulmonary artery hypertension. This study was designed to determine if the naturally occurring antioxidant dihydroxybenzyl alcohol (DHBA) could counteract the deleterious effects of ritonavir (RTV), an HIV-protease inhibitor known to impair endothelial function and increase oxidative stress.

Material/Methods

Antioxidant assays were performed on DHBA in a cell free system. Glutathione (GSH) levels were measured in human pulmonary artery endothelial cells (HPAEC) to determine the effect of DHBA on the level of oxidative stress in cells treated with RTV. Myograph analysis was performed on porcine pulmonary artery (PA) rings after treatment with RTV and/or DHBA. Likewise, reactive oxygen species (ROS) production was assessed in porcine PA rings after RTV +/− DHBA using a lucigenin reaction. Immunohistochemical staining for endothelial nitric oxide synthase (eNOS) was also performed in porcine PAs treated as above.

Results

DHBA demonstrated significant antioxidant activity in a cell free system that surpassed that of vitamin C. Also, treatment with DHBA reduced RTV-induced reduction in endothelium-dependent vasorelaxation and eNOS staining and increased superoxide anion levels. Meanwhile, there was a reversal in RTV-induced oxidative stress leading to reduced GSH levels in HPAECs after treatment with DHBA.

Conclusions

These findings suggest that the naturally occurring antioxidant DHBA reduces the impairment of vasomotor functions caused by RTV in porcine PAs and reduces oxidative stress caused by RTV in HPAEC and porcine PA rings. This study indicates that DHBA may have clinical applications in the prevention or treatment of antiretroviral drugs-associated vascular complications in patients with HIV.

Gingko biloba extract inhibits oxidative stress and ameliorates impaired glial fibrillary acidic protein expression, but can not improve spatial learning in offspring from hyperhomocysteinemic rat dams

We aimed to study the effects of gingko biloba extract (EGb) on oxidative stress, astrocyte maturation and cognitive disfunction in offspring of hyperhomocysteinemic rats. Hyperhomocysteinemia was induced in the pregnant rats by administration of methionine (1 gr/kg body weight) dissolved in drinking water throughout pregnancy. One group of animals has received same amount of methionine plus 100 mg/kg/day EGb during pregnancy. On the postnatal day 1, half of the pups from all groups were sacrificed to study the lipid peroxidation (LPO) in different subfractions of brain. Other half of pups were tested in Morris water maze to assess differences in learning and memory performance at the 75 days of age. Maternal hyperhomocysteinemia significantly increased LPO levels especially in mitochondrial subfraction of fetal pup brains. EGb significantly prevented this LPO inrease. Methionine administration to animals reduced glial fibrillary acidic protein (GFAP) expression in pup brains significantly. EGb administration improved GFAP expression significantly. Offspring of hyperhomocysteinemic animals had poor long term spatial memory performance on Morris water maze and EGb administration had no effect on impaired spatial memory. In conclusion, maternally induced hyperhomocysteinemia significantly increased oxidative stress, decreased expression of GFAP and impaired learning performance.

AVE3085, an enhancer of endothelial nitric oxide synthase, restores endothelial function and reduces blood pressure in spontaneously hypertensive rats

BACKGROUND AND PURPOSE

Nitric oxide (NO) plays an important role in endothelial function, and impaired NO production is involved in hypertension. Therefore, compounds that regulate endothelial NO synthase (eNOS) may be of therapeutic benefit. A novel, low molecular weight compound AVE3085 is a recently developed compound with the ability to enhance eNOS transcription. The present study investigated the effects of AVE3085 in endothelial dysfunction associated with hypertension.

EXPERIMENTAL APPROACH

Spontaneously hypertensive rats (SHRs) were treated with AVE 3085 (10 mg·kg·day(-1) , orally) for 4 weeks. Isometric force measurement was performed on rings of isolated aortae in organ baths. Protein expression of eNOS, phosphorylated-eNOS and nitrotyrosine in the aortae were examined by Western blotting. mRNA for eNOS in rat aortae were examined by reverse-transcriptase polymerase chain reaction (RT-PCR).

KEY RESULTS

AVE3085 greatly improved endothelium-dependent relaxations in the aortae of SHRs. This functional change was accompanied by up-regulated expression of eNOS protein and mRNA, enhanced eNOS phosphorylation and decreased formation of nitrotyrosine. Furthermore, AVE3085 treatment reduced the blood pressure in SHR without affecting that of hypertensive eNOS(-/-) mice.

CONCLUSIONS AND IMPLICATIONS

The eNOS-transcription enhancer AVE3085 restored impaired endothelial function in a hypertensive model. The present study provides a solid basis for the potential development of eNOS-targeting drugs to restore down-regulated eNOS, as a new strategy in hypertension.

Ginkgolide A-gold nanoparticles inhibit vascular smooth muscle proliferation and migration in vitro and reduce neointimal hyperplasia in a mouse model

BACKGROUND

Neointimal formation is mediated by phenotypic changes in vascular smooth muscle cells (SMC) and is an important mediator of restenosis following arterial reconstruction. We conjugated antioxidant ginkgolide A (GA) to gold nanoparticles (GNP) to determine the effect of GA delivery on neointimal formation.

MATERIALS AND METHODS

GA was conjugated to 80 nm GNP in an overnight incubation. Mouse P53LMAC01 vascular SMC were treated with various doses of GA-GNP, GA alone, GNP alone, and no treatment control. Cell proliferation and migration were analyzed, and superoxide anion levels and the phosphorylation status of ERK1/2 were determined. Mice underwent ligation of the common carotid artery along with local treatment with GNP (control) or GA-GNP. The carotid artery was harvested and subjected to immunohistochemical analysis.

RESULTS

GA-GNP treatment significantly inhibited SMC proliferation and migration in vitro in comparison to GNP treatment alone, and the effect persisted for up to 72 h after treatment. Treatment with GA-GNP also reduced superoxide anion levels in vitro. PDGF-BB substantially induced ERK1/2 phosphorylation in GNP control cells; this PDGE-BB induced ERK1/2 phosphorylation was significantly inhibited in GA-GNP-treated cells compared with GNP only. GA-GNP significantly reduced neointimal hyperplasia after injury in mice, and proliferating cell nuclear antigen (PCNA) staining was reduced substantially in the arteries of mice treated with GA-GNP.

CONCLUSIONS

GA-GNP reduce vascular SMC proliferation and migration in vitro through reduced activation of ERK1/2. Local treatment with GA-GNP in areas of arterial injury reduced neointimal hyperplasia and subsequent stenosis.

Roles and mechanisms of human immunodeficiency virus protease inhibitor ritonavir and other anti-human immunodeficiency virus drugs in endothelial dysfunction of porcine pulmonary arteries and human pulmonary artery endothelial cells

The objective of this study was to determine the effects of highly active antiretroviral therapy (HAART) drugs on pulmonary endothelial function. Porcine pulmonary arteries or human pulmonary arterial endothelial cells (HPAECs) were incubated with eight HAART drugs [ritonavir, indinavir, lopinavir, zidovudine (AZT), abacavir, stavudine, didanosine (ddI), and lamivudine] individually or in combination [three HAART drugs (3-plex; indinavir, stavudine, and ddI)] at their clinical plasma concentrations for 24 hours. Endothelium-dependent vasorelaxation in response to bradykinin was reduced significantly by the ritonavir in a concentration-dependent manner. Five other HAART drugs (indinavir, lamivudine, abacavir, AZT, and ddI) and the 3-plex significantly also impaired endothelium-dependent vasorelaxation in response to bradykinin. Five HAART drugs (ritonavir, indinavir, lamivudine, abacavir, and AZT) significantly decreased endothelial nitric oxide synthase (eNOS) expression and increased superoxide anion levels in both vessels and HPAECs. Furthermore, both ritonavir and AZT substantially activated ERK2 in HPAECs. Additionally, the antioxidants ginsenoside Rb1 and ginkgolide A effectively reversed HAART drug-induced vasomotor dysfunction and eNOS down-regulation. Inhibition of ERK1/2 also partially blocked ritonavir- and AZT-induced down-regulation of eNOS and vasomotor dysfunction. Thus, HAART drugs significantly impair endothelial functions of porcine pulmonary arteries and HPAECs, which may be mediated by eNOS down-regulation, oxidative stress, and ERK1/2 activation. These findings suggest that HAART drugs may contribute to the high incidence of pulmonary artery hypertension in human immunodeficiency virus-infected patients.

Inhibitory effect of Ginkgo biloba extract on hyperhomocysteinemia-induced intimal thickening in rabbit abdominal aorta after balloon injury

Ginkgo biloba extract (GBE) has been widely used to treat cardiovascular and cerebrovascular disorders. Hyperhomocysteinemia (Hhcy) is associated with the risk of atherosclerosis and restenosis after angioplasty. The objective of this study was to investigate whether GBE could attenuate the Hhcy-induced intimal thickening after balloon injury in rabbit abdominal aorta. It was observed in this study that GBE could decrease the neointima area (NA) and the ratio of the neointima area to the media area (NA/MA), down-regulate the mRNA expression of matrix metalloproteinase-9 (MMP-9) and up-regulate the protein expression of p21 (WAF1/CIP1) (p21). It suggests that GBE can reverse the Hhcy-induced neointima formation in rabbits following balloon injury, and the suppressive effect of GBE on the migration and proliferation of vascular smooth muscle cells (VSMCs) may contribute to its actions.

Ginkgo biloba extract improves coronary blood flow in healthy elderly adults: role of endothelium-dependent vasodilation

Advancing age decreases endothelial function; accordingly, it alters the physiological regulation of coronary blood flow. Ginkgo biloba extract (GBE) has well-documented anti-ageing effects. However, little is yet known about the pharmacological actions of GBE on endothelial dysfunction and coronary blood flow in healthy elderly adults. We designed the study to test the effects of GBE on distal left anterior descending coronary artery (LAD) blood flow and endothelium-dependent brachial artery flow-mediated dilation (FMD) in healthy elderly adults. Sixty healthy elderly adults were randomly assigned to either GBE or control groups. LAD blood flow and brachial artery FMD were measured non-invasively using high-resolution ultrasound before and after intravenous administration of GBE or saline. GBE significantly increased LAD blood flow in maximal diastolic peak velocity (MDPV), maximal systolic peak velocity (MSPV) and diastolic time velocity integral (DTVI) compared with the placebo group (19.16+/-13.91% vs. 0.30+/-2.55%, 17.76+/-14.56% vs. 0.53+/-2.32%, and 21.73+/-16.13% vs. 0.81+/-2.33%, MDPV, MSPV, and DTVI improvement from baseline, respectively, p<0.01). Brachial artery FMD was also increased by 56.03% (from 7.21+/-2.52% to 11.28+/-3.95%, p<0.01). A linear correlation was found between the percentage change in MDPV, MSPV, or DTVI of LAD blood flow and the percentage change in brachial artery FMD following treatment with GBE (r=0.538, 0.366, or 0.573, respectively, p<0.01, p<0.05, or p<0.01). Our data demonstrate that GBE treatment in healthy elderly adults leads to the increase of LAD blood flow in MDPV, MSPV and DTVI, and the increased response might relate to the improved endothelium-dependent vasodilatory capacity. This study implies an important future therapeutic strategy of using GBE to counteract the detrimental effects of ageing.

Role of asymmetric dimethylarginine in homocysteine-induced apoptosis of vascular smooth muscle cells

Homocysteine (Hcy) could induce apoptosis of vascular smooth muscle cells (VSMC). Asymmetric dimethylarginine (ADMA) has been thought as a novel risk factor for cardiovascular diseases. We hypothesized that ADMA mediates homocysteine-induced apoptosis of VSMC. In this experiment the level of ADMA in the medium measured by high-performance liquid chromatography (HPLC) was elevated when the apoptosis of T/G HA-VSMC was induced by Hcy which was detected by Hoechst33342 staining or flow cytometry (FCM) with Annecin V+Propidium Iodide (PI). Exogenous ADMA induced the apoptosis of VSMC. At the same time, ADMA elevated the level of intracellular reactive oxidative species (ROS) determined by fluorescent ROS detection kit. The activation of JNK and p38MAPK contributed to ADMA-induced apoptosis of VSMC. The present results suggest that endogenous ADMA is involved in apoptosis of VSMC induced by Hcy, and the effects of ADMA is related to elevation of intracellular ROS and activation of JNK/p38MAPK signaling pathways.