The flavonoid quercetin reverses pulmonary hypertension in rats

Comparative analysis of antiproliferative and vasodilator effects of drugs for pulmonary hypertension: Extensive in vitro study in rats and human

An effective pulmonary hypertension (PH) treatment should combine antiproliferative and vasodilator effects. We characterized a wide-range of drugs comparing their anti-proliferative vs vasodilator effects in human and rat pulmonary artery smooth muscle cells (PASMC). Key findings: 1) Approved PH drugs (PDE5 inhibitors, sGC stimulators and PGI2 agonists) are preferential vasodilators. 2) cGMP stimulators were more effective in cells derived from hypertensive rats. 3) Nifedipine acted equally as vasodilator and antiproliferative. 4) quercetin and imatinib were potent dual vasodilator/antiproliferative drugs. 5) Tacrolimus and levosimendan lacked antiproliferative effects. 6) Forskolin, pinacidil and hydroxyfasudil were more effective as antiproliferative in human cells.

Anti-hypertension effect of Wuwei Jiangya decoction via ACE2/Ang1-7/MAS signaling pathway in SHR based on network degree-distribution analysis

ETHNOPHARMACOLOGICAL RELEVANCE

Wuwei Jiangya decoction (WJD) is a traditional Chinese medicinal formula (Fangji) composed of Gastrodiae Rhizoma, Chuanxiong Rhizoma, Puerariae Lobatae Radix, Cyathulae Radix, and Achyranthis Bidentatae Radix, all of which have been verified to combat hypertension. However, the integrative "shot-gun" mechanism of WJD and its primary active ingredients are still unclear.

AIM OF THE STUDY

To investigate the anti-hypertensive effects of WJD and its originating ingredients.

METHODS

Network-based degree distribution analysis combined with in vivo experiments were performed.

RESULTS

A total of 144 active ingredients in WJD were identified to regulate 84 hypertension-related targets, which are mainly involved in blood pressure and blood vessel diameter regulation. However, for the anti-hypertension effects, "more does not mean better". The majority (76%) of the hubs in the H-network were regulated by no more than four ingredients. We identified 16 primary ingredients that accounted for the therapeutic action against hypertension. For compatibility, the five herbs consistently focused on blood pressure, vascular diameter, and angiogenesis, with the renin-angiotensin system as a primary target. The characteristics of each herb were involved in processes such as lipid localization and oxidative stress, which interact to constitute the regulatory network targeting hypertension, its risk factors, and organ damage. In vivo, WJD significantly reduced systolic blood pressure (SBP), improved left ventricular mass index, and ameliorated cardiac hypertrophy and vascular injury by moderating the renin-angiotensin system via activating the ACE2/Ang-(1-7)/Mas signaling pathway.

CONCLUSION

WJD can lower SBP and ameliorate cardiac hypertrophy and vascular injury through the ACE2/Ang-(1-7)/Mas pathway, thus providing new insights into the development of traditional Chinese medicine as a therapeutic agent for hypertension.

An optimized machine learning method for predicting wogonin therapy for the treatment of pulmonary hypertension

Human health is at risk from pulmonary hypertension (PH), characterized by decreased pulmonary vascular resistance and constriction of the pulmonary vessels, resulting in right heart failure and dysfunction. Thus, preventing PH and monitoring its progression before treating it is vital. Wogonin, derived from the leaves of Scutellaria baicalensis Georgi, exhibits remarkable pharmacological activity. In this study, we examined the effectiveness of wogonin in mitigating the progression of PH in mice using right heart catheterization and hematoxylin-eosin (HE) staining. As an alternative to minimize the possibility of harming small animals, we present a scientifically effective feature selection method (BSCDWOA-KELM) that will allow us to develop a novel simpler noninvasive prediction method for wogonin in treating PH. In this method, we use the proposed enhanced whale optimizer (SCDWOA) in conjunction with the kernel extreme learning machine (KELM). Initially, we let SCDWOA perform global optimization experiments on the IEEE CEC2014 benchmark function set to verify its core advantages. Lastly, 12 public and PH datasets are examined for feature selection experiments using BSCDWOA-KELM. As shown in the experimental results for global optimization, the proposed SCDWOA has better convergence performance. Meanwhile, the proposed binary SCDWOA (BSCDWOA) significantly improves the ability of KELM to classify data. By utilizing the BSCDWOA-KELM, key indicators such as the Red blood cell (RBC), the Haemoglobin (HGB), the Lymphocyte percentage (LYM%), the Hematocrit (HCT), and the Red blood cell distribution width-size distribution (RDW-SD) can be efficiently screened in the Pulmonary hypertension dataset, and one of its most essential points is its accuracy of greater than 0.98. Consequently, the BSCDWOA-KELM introduced in this study can be used to predict wogonin therapy for treating pulmonary hypertension in a simple and noninvasive manner.

Vitamin D Receptor Deficiency Upregulates Pulmonary Artery Kv7 Channel Activity

Recent evidence suggests that vitamin D is involved in the development of pulmonary arterial hypertension (PAH). The aim of this study was to analyze the electrophysiological and contractile properties of pulmonary arteries (PAs) in vitamin D receptor knockout mice (Vdr-/-). PAs were dissected and mounted in a wire myograph. Potassium membrane currents were recorded in freshly isolated PA smooth muscle cells (PASMCs) using the conventional whole-cell configuration of the patch-clamp technique. Potential vitamin D response elements (VDREs) in Kv7 channels coding genes were studied, and their protein expression was analyzed. Vdr-/- mice did not show a pulmonary hypertensive phenotype, as neither right ventricular hypertrophy nor endothelial dysfunction was apparent. However, resistance PA from these mice exhibited increased response to retigabine, a Kv7 activator, compared to controls and heterozygous mice. Furthermore, the current sensitive to XE991, a Kv7 inhibitor, was also higher in PASMCs from knockout mice. A possible VDRE was found in the gene coding for KCNE4, the regulatory subunit of Kv7.4. Accordingly, Vdr-/- mice showed an increased expression of KCNE4 in the lungs, with no changes in Kv7.1 and Kv7.4. These results indicate that the absence of Vdr in mice, as occurred with vitamin D deficient rats, is not sufficient to induce PAH. However, the contribution of Kv7 channel currents to the regulation of PA tone is increased in Vdr-/- mice, resembling animals and humans suffering from PAH.

The novel KV7 channel activator URO-K10 exerts enhanced pulmonary vascular effects independent of the KCNE4 regulatory subunit

KV7 channels exert a pivotal role regulating vascular tone in several vascular beds. In this context, KV7 channel agonists represent an attractive strategy for the treatment of pulmonary arterial hypertension (PAH). Therefore, in this study, we have explored the pulmonary vascular effects of the novel KV7 channel agonist URO-K10. Consequently, the vasodilator and electrophysiological effects of URO-K10 were tested in rat and human pulmonary arteries (PA) and PA smooth muscle cells (PASMC) using myography and patch-clamp techniques. Protein expression was also determined by Western blot. Morpholino-induced knockdown of KCNE4 was assessed in isolated PA. PASMC proliferation was measured by BrdU incorporation assay. In summary, our data show that URO-K10 is a more effective relaxant of PA than the classical KV7 activators retigabine and flupirtine. URO-K10 enhanced KV currents in PASMC and its electrophysiological and relaxant effects were inhibited by the KV7 channel blocker XE991. The effects of URO-K10 were confirmed in human PA. URO-K10 also exhibited antiproliferative effects in human PASMC. Unlike retigabine and flupirtine, URO-K10-induced pulmonary vasodilation was not affected by morpholino-induced knockdown of the KCNE4 regulatory subunit. Noteworthy, the pulmonary vasodilator efficacy of this compound was considerably increased under conditions mimicking the ionic remodelling (as an in vitro model of PAH) and in PA from monocrotaline-induced pulmonary hypertensive rats. Taking all together, URO-K10 behaves as a KCNE4-independent KV7 channel activator with much increased pulmonary vascular effects compared to classical KV7 channel activators. Our study identifies a promising new drug in the context of PAH.

Impact of a TAK-1 inhibitor as a single or as an add-on therapy to riociguat on the metabolic reprograming and pulmonary hypertension in the SUGEN5416/hypoxia rat model

Background: Despite increasing evidence suggesting that pulmonary arterial hypertension (PAH) is a complex disease involving vasoconstriction, thrombosis, inflammation, metabolic dysregulation and vascular proliferation, all the drugs approved for PAH mainly act as vasodilating agents. Since excessive TGF-β signaling is believed to be a critical factor in pulmonary vascular remodeling, we hypothesized that blocking TGFβ-activated kinase 1 (TAK-1), alone or in combination with a vasodilator therapy (i.e., riociguat) could achieve a greater therapeutic benefit.

Methods: PAH was induced in male Wistar rats by a single injection of the VEGF receptor antagonist SU5416 (20 mg/kg) followed by exposure to hypoxia (10%O2) for 21 days. Two weeks after SU5416 administration, vehicle, riociguat (3 mg/kg/day), the TAK-1 inhibitor 5Z-7-oxozeaenol (OXO, 3 mg/kg/day), or both drugs combined were administered for 7 days. Metabolic profiling of right ventricle (RV), lung tissues and PA smooth muscle cells (PASMCs) extracts were performed by magnetic resonance spectroscopy, and the differences between groups analyzed by multivariate statistical methods.

Results:In vitro, riociguat induced potent vasodilator effects in isolated pulmonary arteries (PA) with negligible antiproliferative effects and metabolic changes in PASMCs. In contrast, 5Z-7-oxozeaenol effectively inhibited the proliferation of PASMCs characterized by a broad metabolic reprogramming but had no acute vasodilator effects. In vivo, treatment with riociguat partially reduced the increase in pulmonary arterial pressure (PAP), RV hypertrophy (RVH), and pulmonary vascular remodeling, attenuated the dysregulation of inosine, glucose, creatine and phosphocholine (PC) in RV and fully abolished the increase in lung IL-1β expression. By contrast, 5Z-7-oxozeaenol significantly reduced pulmonary vascular remodeling and attenuated the metabolic shifts of glucose and PC in RV but had no effects on PAP or RVH. Importantly, combined therapy had an additive effect on pulmonary vascular remodeling and induced a significant metabolic effect over taurine, amino acids, glycolysis, and TCA cycle metabolism via glycine-serine-threonine metabolism. However, it did not improve the effects induced by riociguat alone on pulmonary pressure or RV remodeling. None of the treatments attenuated pulmonary endothelial dysfunction and hyperresponsiveness to serotonin in isolated PA.

Conclusion: Our results suggest that inhibition of TAK-1 induces antiproliferative effects and its addition to short-term vasodilator therapy enhances the beneficial effects on pulmonary vascular remodeling and RV metabolic reprogramming in experimental PAH.

Traditional Chinese medicine monomers: Targeting pulmonary artery smooth muscle cells proliferation to treat pulmonary hypertension

Pulmonary hypertension (PH) is a complex multifactorial disease characterized by increased pulmonary vascular resistance and pulmonary vascular remodeling (PVR), with high morbidity, disability, and mortality. The abnormal proliferation of pulmonary artery smooth muscle cells (PASMCs) is the main pathological change causing PVR. At present, clinical treatment drugs for PH are limited, which can only improve symptoms and reduce hospitalization but cannot delay disease progression and reduce survival rate. In recent years, numerous studies have shown that traditional Chinese medicine monomers (TCMs) inhibit excessive proliferation of PASMCs resulting in alleviating PVR through multiple channels and multiple targets, which has attracted more and more attention in the treatment of PH. In this paper, the experimental evidence of inhibiting PASMCs proliferation by TCMs was summarized to provide some directions for the future development of these mentioned TCMs as anti-PH drugs in clinical.

Flavonoids as Modulators of Potassium Channels

Potassium channels are widely distributed integral proteins responsible for the effective and selective transport of K+ ions through the biological membranes. According to the existing structural and mechanistic differences, they are divided into several groups. All of them are considered important molecular drug targets due to their physiological roles, including the regulation of membrane potential or cell signaling. One of the recent trends in molecular pharmacology is the evaluation of the therapeutic potential of natural compounds and their derivatives, which can exhibit high specificity and effectiveness. Among the pharmaceuticals of plant origin, which are potassium channel modulators, flavonoids appear as a powerful group of biologically active substances. It is caused by their well-documented anti-oxidative, anti-inflammatory, anti-mutagenic, anti-carcinogenic, and antidiabetic effects on human health. Here, we focus on presenting the current state of knowledge about the possibilities of modulation of particular types of potassium channels by different flavonoids. Additionally, the biological meaning of the flavonoid-mediated changes in the activity of K+ channels will be outlined. Finally, novel promising directions for further research in this area will be proposed.

Network Pharmacology and Molecular Docking Analysis of Shufeiya Recipe in the Treatment of Pulmonary Hypertension

Objective

This study is aimed at exploring the molecular mechanism of Shufeiya recipe in the treatment of pulmonary hypertension (PH) using network pharmacology and molecular docking analysis.

Methods

Active components and their target proteins in the recipe were screened using the TCMSP database. PH-related core proteins were screened using GeneCards, STRING database, and Cytoscape-v3.8.2. Common proteins were obtained by intersection of the target proteins of these recipe active components and pH-related core proteins. Rx64 4.0.2 software was used to perform GO functional enrichment analysis and KEGG pathway enrichment analysis on the common proteins to obtain pathway-enriched proteins, and then core enriched proteins were further screened. We analyzed the relationship between the active components and pathway-enriched proteins using Cytoscape-v3.8.2. AutoDock Vina was used to dock their core proteins into the components.

Results

Shufeiya recipe contained 67 active components. 61 common proteins of the target proteins of the active components and PH-related core proteins were obtained. The treatment involved both functional and pathway regulations. The core pathway-enriched proteins were prostaglandin G/H synthase 2 (PTGS2), epidermal growth factor receptor (EGFR), and RAC-alpha serine/threonine-protein kinase (AKT1), and their binding energies to the corresponding components were all less than -5 kJ•mol-1.

Conclusion

It was found that the main mechanism might be the active components acting on the core pathway-enriched proteins to regulate related signaling pathways, thereby playing roles in anticoagulation, vasodilation, anti-PASMC proliferation, promotion of PAECs apoptosis, inhibition of oxidative stress, and anti-inflammatory effects.

Ligand effect on controlling the synthesis of branched gold nanomaterials against fusarium wilt diseases

The widespread wilt disease caused by Fusarium solani spp is a pressing problem affecting crop production and intensive farming. Strategic biocontrol of Fusarium solani spp using phytochemical mediated nano-materials is eco-friendly compared to harsh synthetic fungicides. The present study demonstrates the comparative dose effects of QPABA-derived branched gold nanomaterial (AuNF) and quercetin-mediated spherical gold nanoparticles (s-AuNPs) against Fusarium solani spp. Quercetin-para aminobenzoic acid (QPABA) was synthesized using reductive amination by reacting para-aminobenzoic acid with quercetin in an eco-friendly solvent at 25 °C. The structure elucidation was confirmed using ¹H and ¹³C-NMR. TLC analysis showed that QPABA (R _f = 0.628) was more polar in water than quercetin (R _f = 0.714). The as-synthesized QPABA serves as a reducing and capping agent for the synthesis of gold nanoflowers (AuNFs) and gold nanostars (AuNSs). The UV-vis, XRD, and TEM confirmed the SPR peak of gold (550 nm) and gold element with a particle size distribution of 20-80 nm for the nanostars respectively. AuNFs exhibited a significant (P < 0.05) inhibitory effect against F. solani in a dose-dependent manner using Agar well diffusion. Nevertheless, spherical-AuNPs were not effective against F. solani. The inhibitory effect was influenced by the size, dose treatment, and particle shape. The minimum inhibitory concentration (MIC) value of AuNFs was 125.7 ± 0.22 μg mL^-1. Our results indicate that AuNFs show considerable antifungal activity against F. solani as compared to spherical AuNPs. This study shows a greener synthesis of gold anisotropic nanostructures using QPAB, which holds promise for the treatment of fungal pathogens impacting agricultural productivity.

Antidepressant Potential of Quercetin and its Glycoside Derivatives: A Comprehensive Review and Update

Depression is a global health problem with growing prevalence rates and serious impacts on the daily life of patients. However, the side effects of currently used antidepressants greatly reduce the compliance of patients. Quercetin is a flavonol present in fruits, vegetables, and Traditional Chinese medicine (TCM) that has been proved to have various pharmacological effects such as anti-depressant, anti-cancer, antibacterial, antioxidant, anti-inflammatory, and neuroprotective. This review summarizes the evidence for the pharmacological application of quercetin to treat depression. We clarified the mechanisms of quercetin regulating the levels of neurotransmitters, promoting the regeneration of hippocampal neurons, improving hypothalamic-pituitary-adrenal (HPA) axis dysfunction, and reducing inflammatory states and anti-oxidative stress. We also summarized the antidepressant effects of some quercetin glycoside derivatives to provide a reference for further research and clinical application.

Chronic and moderate consumption of reduced-alcohol wine confers cardiac benefits in a rat model of pulmonary arterial hypertension

OBJECTIVES

In pulmonary arterial hypertension (PAH), right ventricular (RV) dysfunction develops via mechanisms involving oxidative stress. Moderate and chronic red wine (RW) consumption reduces oxidative stress and confers cardioprotection but its effect on PAH is unknown. We evaluated whether moderate and chronic consumption of reduced-alcohol RW (RARW) confers cardioprotection in a monocrotaline (MCT)-induced PAH rat model.

RESULTS

Rats were randomly grouped: control; MCT; RARW; MCT + RARW. Wine was diluted to mimic moderate intake for humans, and consumed from 7 days before, until 28 days after MCT-injection. Echocardiography measured pulmonary artery acceleration time (PAAT) and RV thickness. Conjugated dienes (CD), and thiobarbituric acid reactive substances (TBARS) concentrations were assessed. MCT induced RV thickness and decreased PAAT compared to controls [1.22 ± 0.09 mm vs 0.46 ± 0.02 mm and 14 ± 1 vs 23 ± 2 m/s, respectively (p < 0.001)]. Chronic RARW consumption limited MCT-induced RV hypertrophy and increased PAAT. CD and TBARS increased in MCT-treated animals compared to controls (672 ± 43 nmol/L vs 453 ± 35 nmol/L; p < 0.01 and 13 ± 2 µmol/L vs 4 ± 0.3 µmol/L; p < 0.01). RARW reduced MCT-induced CD (472 ± 27 nmol/L vs 672 ± 43 nmol/L; p < 0.01).

CONCLUSION

Chronic and moderate intake of RARW ameliorates MCT-induced PAH in rats, which may be partly attributable to reduction of lipid peroxidation.

Bioactive Compounds From Coptidis Rhizoma Alleviate Pulmonary Arterial Hypertension by Inhibiting Pulmonary Artery Smooth Muscle Cells' Proliferation and Migration

ABSTRACT

Pulmonary arterial hypertension (PAH) is a devastating disorder characterized by excessive proliferation and vasoconstriction of small pulmonary artery vascular smooth muscle cells (PASMCs). Coptidis rhizoma (CR) because of the complexity of the components, the underlying pharmacological role and mechanism of it on PAH remains unknown. In this article, the network pharmacological analysis was used to screen the main active constituents of CR and the molecular targets that these constituents act on. Then, we evaluated the importance of berberine and quercetin (biologically active components of CR) on the proliferation and migration of PASMCs and vascular remodeling in experimental models of PAH. Our results showed that berberine and quercetin effectively inhibited the proliferation and migration of hypoxia-induced PASMCs in a manner likely to be mediated by the suppression of MAPK1, NADPH oxidase 4 (NOX4), and cytochrome P450 1B1 (CYP1B1) expression. Furthermore, berberine and quercetin treatment attenuates pulmonary hypertension, reduces right ventricular hypertrophy, and improves pulmonary artery remodeling in monocrotaline-induced pulmonary hypertension in rat models. In conclusion, this research demonstrates CR might be a promising treatment option for PAH, and the network pharmacology approach can be an effective tool to reveal the potential mechanisms of Chinese herbal medicine.

Pulmonary arterial hypertension and flavonoids: A role in treatment

Pulmonary arterial hypertension (PAH) is a high mortality progressive pulmonary vascular disease that can lead to right heart failure. The use of clinical drugs for the treatment of PAH is limited to a great extent because of its single target and high price. Flavonoids are widely distributed in nature, and have been found in fruits, vegetables, and traditional Chinese medicine. They have diverse biological activities and various pharmacological effects such as antitumor, antioxidation, and anti-inflammatory. This review summarizes the progress in pharmacodynamics and mechanism of flavonoids in the treatment of PAH in recent years, in order to provide some theoretical references for relevant researchers.

Quercetin and metabolic syndrome: A review

Metabolic syndrome (MetS) is a complex of diseases that lead to mortality due to the development of cardiovascular problems. Quercetin, as an important flavonoid, has various properties such as decreasing blood pressure, anti-hyperlipidemia, anti-hyperglycemia, anti-oxidant, antiviral, anticancer, anti-inflammatory, anti-microbial, neuroprotective, and cardio-protective effects. In this review article, we collected original articles from different sources such as Google Scholar, Medline, Scopus, and Pubmed, which is related to the effect of quercetin on the improvement of the signs of MetS, including elevated glucose level, hyperlipidemia, obesity, and blood pressure. According to these data, quercetin may also have a role in the management of metabolic disorders via different mechanisms such as increasing adiponectin, decreasing leptin, anti-oxidant activity, reduction of insulin resistance, the elevation of insulin level, and blocking of calcium channel. We have attempted to make some recommendations on the quercetin application in patients. However, it needs to do further clinical trials and more investigations to show the real clinical value of quercetin on metabolic syndrome.

Increased acute blood flow induced by the aqueous extract of Euterpe oleracea Mart. fruit pulp in rats in vivo is not related to the direct activation of endothelial cells

ETHNOPHARMACOLOGICAL RELEVANCE

Scientific evidence supports the antioxidant, anti-inflammatory and anti-lipidemic properties of Euterpe oleracea Mart. (açaí), which all converge to reduce cardiovascular risks. Macerating the pulp of açaí fruit produces a viscous aqueous extract (AE) rich in flavonoids that is commonly used in food production. In addition to nutritional aspects, cardiovascular benefits are attributed to AE by traditional medicine.

AIM OF THE STUDY

Evaluation of AE impact on blood flow in vivo in rats and investigation of the mechanism underlying this response in vitro in rat endothelial cells (RECs).

MATERIALS AND METHODS

For the measurement of acute blood flow, a perivascular ultrasound probe was used in Wistar rats. The in vitro assays employed REC to evaluate: concentration (1-1000 μg/mL) and time response (2-180 min) of AE in MTT cell viability assays; nitric oxide (NO) levels measurement and intracellular calcium handling using DAF-2DA and Fluo-4-AM, respectively; cellular biopterin content by HPLC; activation of Akt pathway using western blot analysis. For the chemical analyses of AE, stock solutions of the standards (+)catechin and quercetin were used for obtaining linear calibration curves. Identification and quantification of flavonoids in AE were based on comparisons with the retention times, increase in peak area determine by co-injection of AE with standards, UV-Vis scan and standard curves of known spectra. Results were expressed as mean ± standard deviation and data were analyzed using ANOVA followed by Tukey's post-test (p < 0.05).

RESULTS

Although in vivo data have revealed the participation of NO in increasing of acute blood flow on abdominal aorta, in vitro analysis demonstrated that vasodilatation AE-induced is not related to its direct action on endothelial cells inducing eNOS activation. Besides, we demonstrated in isolated endothelial cells that highest concentrations of AE caused a reduction in NO levels, effect that could be partly justified by inhibition of Akt phosphorylation which, in turn, could decrease NOS activation. The involvement of cell transduction pathways involving variations in intracellular calcium and biopterins concentration were discarded. The participation of catechin and quercetin, identified in AE, was postulated to induce the responses of AE in REC.

CONCLUSIONS

Despite the responses in vitro, vasodilation prevailed in vivo, probably by activating intermediate pathways, validating a potential beneficial effect of AE in reducing cardiovascular risks.

Preventive effects of nitrate-rich beetroot juice supplementation on monocrotaline-induced pulmonary hypertension in rats

Beetroot (Beta vulgaris L.) has a high level of nitrate; therefore, its dietary intake could increase nitric oxide (NO) level in the body, possibly preventing the development of pulmonary hypertension (PH). In this study, we examined the effects of beetroot juice (BJ) supplementation on PH and the contribution of nitrate to such effects using a rat model of monocrotaline (MCT, 60 mg/kg s.c.)-induced PH. Rats were injected subcutaneously with saline or 60 mg/kg MCT and were sacrificed 28 days after the injection. In some rats injected with MCT, BJ was supplemented from the day of MCT injection to the day of sacrifice. First, MCT-induced right ventricular systolic pressure elevation, pulmonary arterial medial thickening and muscularization, and right ventricular hypertrophy were suppressed by supplementation with low-dose BJ (nitrate: 1.3 mmol/L) but not high-dose BJ (nitrate: 4.3 mmol/L). Of the plasma nitrite, nitrate, and their sum (NOx) levels, only the nitrate levels were found to be increased by the high-dose BJ supplementation. Second, in order to clarify the possible involvement of nitrate in the preventive effects of BJ on PH symptoms, the effects of nitrate-rich BJ (nitrate: 0.9 mmol/L) supplementation were compared with those of the nitrate-depleted BJ. While the former exerted preventive effects on PH symptoms, such effects were not observed in rats supplemented with nitrate-depleted BJ. Neither supplementation with nitrate-rich nor nitrate-depleted BJ affected plasma nitrite, nitrate, and NOx levels. These findings suggest that a suitable amount of BJ ingestion, which does not affect systemic NO levels, can prevent the development of PH in a nitrate-dependent manner. Therefore, BJ could be highly useful as a therapy in patients with PH.

Potassium (K+) channels in the pulmonary vasculature: Implications in pulmonary hypertension Physiological, pathophysiological and pharmacological regulation

The large K⁺ channel functional diversity in the pulmonary vasculature results from the multitude of genes expressed encoding K⁺ channels, alternative RNA splicing, the post-transcriptional modifications, the presence of homomeric or heteromeric assemblies of the pore-forming α-subunits and the existence of accessory β-subunits modulating the functional properties of the channel. K⁺ channels can also be regulated at multiple levels by different factors controlling channel activity, trafficking, recycling and degradation. The activity of these channels is the primary determinant of membrane potential (Em) in pulmonary artery smooth muscle cells (PASMC), providing an essential regulatory mechanism to dilate or contract pulmonary arteries (PA). K⁺ channels are also expressed in pulmonary artery endothelial cells (PAEC) where they control resting Em, Ca²⁺ entry and the production of different vasoactive factors. The activity of K⁺ channels is also important in regulating the population and phenotype of PASMC in the pulmonary vasculature, since they are involved in cell apoptosis, survival and proliferation. Notably, K⁺ channels play a major role in the development of pulmonary hypertension (PH). Impaired K⁺ channel activity in PH results from: 1) loss of function mutations, 2) downregulation of its expression, which involves transcription factors and microRNAs, or 3) decreased channel current as a result of increased vasoactive factors (e.g., hypoxia, 5-HT, endothelin-1 or thromboxane), exposure to drugs with channel-blocking properties, or by a reduction in factors that positively regulate K⁺ channel activity (e.g., NO and prostacyclin). Restoring K⁺ channel expression, its intracellular trafficking and the channel activity is an attractive therapeutic strategy in PH.

Uncovered Contribution of Kv7 Channels to Pulmonary Vascular Tone in Pulmonary Arterial Hypertension

K + channels play a fundamental role regulating membrane potential of pulmonary artery (PA) smooth muscle cells and their impairment is a common feature in pulmonary arterial hypertension (PAH). K + voltage-gated channel subfamily Q ( KCNQ1-5 ) or Kv7 channels and their regulatory subunits subfamily E (KCNE) regulatory subunits are known to regulate vascular tone, but whether Kv7 channel function is impaired in PAH and how this can affect the rationale for targeting Kv7 channels in PAH remains unknown. Here, we have studied the role of Kv7/KCNE subunits in rat PA and their possible alteration in PAH. Using the patch-clamp technique, we found that the total K + current is reduced in PA smooth muscle cells from pulmonary hypertension animals (SU5416 plus hypoxia) and Kv7 currents made a higher contribution to the net K + current. Likewise, enhanced vascular responses to Kv7 channel modulators were found in pulmonary hypertension rats. Accordingly, KCNE4 subunit was highly upregulated in lungs from pulmonary hypertension animals and patients. Additionally, Kv7 channel activity was enhanced in the presence of Kv1.5 and TASK-1 channel inhibitors and this was associated with an increased KCNE4 membrane abundance. Compared with systemic arteries, PA showed a poor response to Kv7 channel modulators which was associated with reduced expression and membrane abundance of Kv7.4 and KCNE4. Our data indicate that Kv7 channel function is preserved and KCNE4 is upregulated in PAH. Therefore, compared with other downregulated channels, the contribution of Kv7 channels is increased in PAH resulting in an enhanced sensitivity to Kv7 channel modulators. This study provides insight into the potential usefulness of targeting Kv7 channels in PAH.

Vitamin D deficiency downregulates TASK-1 channels and induces pulmonary vascular dysfunction

Vitamin D (VitD) receptor regulates the expression of several genes involved in signaling pathways affected in pulmonary hypertension (PH). VitD deficiency is highly prevalent in PH, and low levels are associated with poor prognosis. We investigated if VitD deficiency may predispose to or exacerbate PH. Male Wistar rats were fed with a standard or a VitD-free diet for 5 wk. Next, rats were further divided into controls or PH, which was induced by a single dose of Su-5416 (20 mg/kg) and exposure to hypoxia (10% O2) for 2 wk. VitD deficiency had no effect on pulmonary pressure in normoxic rats, indicating that, by itself, it does not trigger PH. However, it induced several moderate but significant changes characteristic of PH in the pulmonary arteries, such as increased muscularization, endothelial dysfunction, increased survivin, and reduced bone morphogenetic protein ( Bmp) 4, Bmp6, DNA damage-inducible transcript 4, and K+ two - pore domain channel subfamily K member 3 ( Kcnk3) expression. Myocytes isolated from pulmonary arteries from VitD-deficient rats had a reduced whole voltage-dependent potassium current density and acid-sensitive (TASK-like) potassium currents. In rats with PH induced by Su-5416 plus hypoxia, VitD-free diet induced a modest increase in pulmonary pressure, worsened endothelial function, increased the hyperreactivity to serotonin, arterial muscularization, decreased total and TASK-1 potassium currents, and further depolarized the pulmonary artery smooth muscle cell membrane. In human pulmonary artery smooth muscle cells from controls and patients with PH, the active form of VitD calcitriol significantly increased KCNK3 mRNA expression. Altogether, these data strongly suggest that the deficit in VitD induces pulmonary vascular dysfunction.

hsa_circNFXL1_009 modulates apoptosis, proliferation, migration, and potassium channel activation in pulmonary hypertension

In this study, we explored the circular RNA (circRNA) profile in pulmonary arterial hypertension (PAH) patients caused by chronic obstructive pulmonary disease (COPD) and the effects of hsa_circNFXL1_009 on abnormal proliferation, apoptosis, and migration of human pulmonary arterial smooth muscle cells (hPASMCs) driven by hypoxia. Using microarrays, we screened the circRNA profile in whole-blood samples from three pairs of subjects and found 158 dysregulated circRNAs in patients with PAH-COPD. Quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) analysis further validated that hsa_circNFXL1_009 was dramatically downregulated with the highest area under a receiver operating characteristic curve (ROC) in 21 pairs of subjects. Consistently, exposure to hypoxia markedly reduced the hsa_circNFXL1_009 level in cultured hPASMCs. Delivery of exogenous hsa_circNFXL1_009 attenuated hypoxia-induced proliferation, apoptotic resistance, and migration of hPASMCs, as evidenced by immunocytochemistry, 5-ethynyl-2′-deoxyuridine incorporation, wound healing, and a TUNEL (terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling) assay. A luciferase assay showed that hsa_circNFXL1_009 directly sponged hsa-miR-29b-2-5p (miR-29b) and positively regulated the expression of voltage-gated potassium (K⁺) channel subfamily B member 1 (KCNB1) at the mRNA level. Using patch-clamp electrophysiology, we proved that overexpression of hsa_circNFXL1_009 promoted a whole-cell K⁺ current in hPASMCs. Taken together, these studies identify hsa_circNFXL1_009 as a key regulator of PAH, and it may be used as a potential therapeutic target for the treatment of PAH.

Protective effect of quercetin against myocardial ischemia as a Ca2+ channel inhibitor: involvement of inhibiting contractility and Ca2+ influx via L-type Ca2+ channels

Many studies describe the stimulating effect of quercetin on Ca²⁺ channels and the treatment of cardiovascular diseases such as myocardial ischemia and hypertension. However, these studies are scattered and contradictory. The aim of this study is to elucidate the protective effects of quercetin against isoproterenol (ISO)-induced myocardial ischemia and verify the cellular mechanisms based on the L-type Ca²⁺ channel (LTCC), Ca²⁺ transients, and myocardial contractility. An animal model of myocardial ischemia was established by subcutaneous injection of ISO for 2 days. Quercetin significantly reduced J-point elevation, heart rate, reactive oxygen species, serum levels of myocardial enzymes, superoxide dismutase, catalase, glutathione, glutathione peroxidase, glutathione S-transferase and improved heart pathologic morphology. L-type Ca²⁺ current (I_Ca-L) was tested in an experiment with isolated rat myocardial cells by using the whole-cell patch-clamp recording technique and IonOptix Myocam detection system. Quercetin reduced I_Ca-L in a concentration-dependent fashion with a half-maximal inhibitory concentration of 4.67 × 10^-4 M. Quercetin also shifted the current-voltage curve upwards, moved the activation and inactivation curves to the left and inhibited the amplitude of the cell shortening and Ca²⁺ transients. The results showed that quercetin acts as a LTCC inhibitor and exerts a cardioprotective effect by inhibiting Ca²⁺ influx and contractility in rats.

Nutraceuticals in the Treatment of Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a severe disease characterized by the loss and obstructive remodeling of the pulmonary arterial wall, causing a rise in pulmonary arterial pressure and pulmonary vascular resistance, which is responsible for right heart failure, functional decline, and death. Although many drugs are available for the treatment of this condition, it continues to be life-threatening, and its long-term treatment is expensive. On the other hand, many natural compounds present in food have beneficial effects on several cardiovascular conditions. Several studies have explored many of the potential beneficial effects of natural plant products on PAH. However, the mechanisms by which natural products, such as nutraceuticals, exert protective and therapeutic effects on PAH are not fully understood. In this review, we analyze the current knowledge on nutraceuticals and their potential use in the protection and treatment of PAH, as well as whether nutraceuticals could enhance the effects of drugs used in PAH through similar mechanisms.

Kv7 Channels in Lung Diseases

Lung diseases constitute a global health concern causing disability. According to WHO in 2016, respiratory diseases accounted for 24% of world population mortality, the second cause of death after cardiovascular diseases. The Kv7 channels family is a group of voltage-dependent K⁺ channels (Kv) encoded by KCNQ genes that are involved in various physiological functions in numerous cell types, especially, cardiac myocytes, smooth muscle cells, neurons, and epithelial cells. Kv7 channel α-subunits are regulated by KCNE1–5 ancillary β-subunits, which modulate several characteristics of Kv7 channels such as biophysical properties, cell-location, channel trafficking, and pharmacological sensitivity. Kv7 channels are mainly expressed in two large groups of lung tissues: pulmonary arteries (PAs) and bronchial tubes. In PA, Kv7 channels are expressed in pulmonary artery smooth muscle cells (PASMCs); while in the airway (trachea, bronchus, and bronchioles), Kv7 channels are expressed in airway smooth muscle cells (ASMCs), airway epithelial cells (AEPs), and vagal airway C-fibers (VACFs). The functional role of Kv7 channels may vary depending on the cell type. Several studies have demonstrated that the impairment of Kv7 channel has a strong impact on pulmonary physiology contributing to the pathophysiology of different respiratory diseases such as cystic fibrosis, asthma, chronic obstructive pulmonary disease, chronic coughing, lung cancer, and pulmonary hypertension. Kv7 channels are now recognized as playing relevant physiological roles in many tissues, which have encouraged the search for Kv7 channel modulators with potential therapeutic use in many diseases including those affecting the lung. Modulation of Kv7 channels has been proposed to provide beneficial effects in a number of lung conditions. Therefore, Kv7 channel openers/enhancers or drugs acting partly through these channels have been proposed as bronchodilators, expectorants, antitussives, chemotherapeutics and pulmonary vasodilators.

Medicinal Plants and Phytochemicals for the Treatment of Pulmonary Hypertension

Background

Pulmonary hypertension (PH) is a progressive disease that is associated with pulmonary arteries remodeling, right ventricle hypertrophy, right ventricular failure and finally death. The present study aims to review the medicinal plants and phytochemicals used for PH treatment in the period of 1994 – 2019.

Methods

PubMed, Cochrane and Scopus were searched based on pulmonary hypertension, plant and phytochemical keywords from August 23, 2019. All articles that matched the study based on title and abstract were collected, non-English, repetitive and review studies were excluded.

Results

Finally 41 studies remained from a total of 1290. The results show that many chemical treatments considered to this disease are ineffective in the long period because they have a controlling role, not a therapeutic one. On the other hand, plants and phytochemicals could be more effective due to their action on many mechanisms that cause the progression of PH.

Conclusion

Studies have shown that herbs and phytochemicals used to treat PH do their effects from six mechanisms. These mechanisms include antiproliferative, antioxidant, antivascular remodeling, anti-inflammatory, vasodilatory and apoptosis inducing actions. According to the present study, many of these medicinal plants and phytochemicals can have effects that are more therapeutic than chemical drugs if used appropriately.

Hypoxia induces an increase in intestinal permeability and pulmonary arterial pressures in neonatal Holstein calves despite feeding the flavonoid rutin

The purposes of this study were to determine whether the naturally occurring flavonoid quercetin, as its glucorhamnoside rutin, reduces intestinal permeability and susceptibility to hypoxia-induced pulmonary hypertension in neonatal Holstein calves. A 2 × 2 between-subjects factorial design was conducted using Holstein steers (n = 16). Factors included oxygen level (simulated altitude of 4,572 m vs. 975 m) and quercetin supplementation as its glucorhamnoside rutin (4 g of quercetin per day vs. 0 g per day). Two days after arrival (d 0 of study) the calves were blocked by body mass into treatment groups, and treatments were initiated. Pulmonary arterial pressure, echocardiography, and serum concentrations of orally administered lactulose (0.45 g/kg) and mannitol (0.15 g/kg) were measured on d 12, 13, and 14, respectively. Calves were euthanized on d 15 and pulmonary tissues collected for semiquantitative scoring of histological lesions. Data were analyzed using linear regression, generalized estimating equations, and 2-sample proportion tests. Hypoxia, but not rutin, was found to be associated with intestinal permeability. The lactulose-mannitol ratio was 0.54 ± 0.13 (standard error) in hypoxic calves and 0.02 ± 0.13 in normoxic controls. Hypoxia increased mean pulmonary arterial pressure. Calves fed rutin under hypoxic conditions tended to have a lower mean pulmonary arterial pressure (59 ± 7 mmHg) than control calves (80 ± 7 mmHg) but similar pressures under normoxic conditions. Paradoxically, however, a greater proportion of calves fed rutin had histological evidence of pulmonary arteriolar medial hypertrophy and adventitial hyperplasia than did controls. In conclusion, the findings of this study indicate that hypoxia increased intestinal permeability in neonatal calves. The flavonoid quercetin, as its glucorhamnoside rutin, had no protective effect on intestinal permeability, and, although it tended to reduce the severity of hypoxia-induced pulmonary hypertension, a greater proportion of calves fed rutin had histological lesions consistent with pulmonary arteriolar remodeling.

Impact of Nutrition on Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is characterized by sustained vasoconstriction, vascular remodeling, inflammation, and in situ thrombosis. Although there have been important advances in the knowledge of the pathophysiology of PAH, it remains a debilitating, limiting, and rapidly progressive disease. Vitamin D and iron deficiency are worldwide health problems of pandemic proportions. Notably, these nutritional alterations are largely more prevalent in PAH patients than in the general population and there are several pieces of evidence suggesting that they may trigger or aggravate disease progression. There are also several case reports associating scurvy, due to severe vitamin C deficiency, with PAH. Flavonoids such as quercetin, isoflavonoids such as genistein, and other dietary polyphenols including resveratrol slow the progression of the disease in animal models of PAH. Finally, the role of the gut microbiota and its interplay with the diet, host immune system, and energy metabolism is emerging in multiple cardiovascular diseases. The alteration of the gut microbiota has also been reported in animal models of PAH. It is thus possible that in the near future interventions targeting the nutritional status and the gut dysbiosis will improve the outcome of these patients.

Quercetin Exerts Age-Dependent Beneficial Effects on Blood Pressure and Vascular Function, But Is Inefficient in Preventing Myocardial Ischemia-Reperfusion Injury in Zucker Diabetic Fatty Rats

Background: Quercetin (QCT) was shown to exert beneficial cardiovascular effects in young healthy animals. The aim of the present study was to determine cardiovascular benefits of QCT in older, 6-month and 1-year-old Zucker diabetic fatty (ZDF) rats (model of type 2 diabetes). Methods: Lean (fa/+) and obese (fa/fa) ZDF rats of both ages were treated with QCT for 6 weeks (20 mg/kg/day). Isolated hearts were exposed to ischemia-reperfusion (I/R) injury (30 min/2 h). Endothelium-dependent vascular relaxation was measured in isolated aortas. Expression of selected proteins in heart tissue was detected by Western blotting. Results: QCT reduced systolic blood pressure in both lean and obese 6-month-old rats but had no effect in 1-year-old rats. Diabetes worsened vascular relaxation in both ages. QCT improved vascular relaxation in 6-month-old but worsened in 1-year-old obese rats and had no impact in lean controls of both ages. QCT did not exert cardioprotective effects against I/R injury and even worsened post-ischemic recovery in 1-year-old hearts. QCT up-regulated expression of eNOS in younger and PKCε expression in older rats but did not activate whole PI3K/Akt pathway. Conclusions: QCT might be beneficial for vascular function in diabetes type 2; however, increasing age and/or progression of diabetes may confound its vasculoprotective effects. QCT seems to be inefficient in preventing myocardial I/R injury in type 2 diabetes and/or higher age. Impaired activation of PI3K/Akt kinase pathway might be, at least in part, responsible for failing cardioprotection in these subjects.

Effects of phytochemicals on cellular signaling: reviewing their recent usage approaches

Most of the previous studies in last three decades report evidence of interactions between the different phytochemicals and the proteins involved in signal transduction pathways using in silico, in vitro, ex vivo, and in vivo analyses. However, extrapolation of these findings for clinical purposes has not been that fruitful. The efficacy of the phytochemicals in vivo studies is limited by parameters such as solubility, metabolic degradation, excretion, etc. Various approaches have now been devised to circumvent these limitations. Recently, chemical modification of the phytochemicals are demonstrated to reduce some of the limitations and improve their efficacy. Similar to traditional medicines several combinatorial phytochemical formulations have shown to be more efficient. Further, phytochemicals have been reported to be even more efficient in the form of nanoparticles. However, systematic evaluation of their efficacy, mode of action in pathway modulation, usage and associated challenges is required to be done. The present review begins with basic understanding of how signaling cascades regulate cellular response and the consequences of their dysregulation further summarizing the developments and problems associated with the dietary phytochemicals and also discuss recent approaches in strengthening these compounds in pharmacological applications. Only context relevant studies have been reviewed. Considering the limitations and scope of the article, authors do not claim inclusion of all the early and recent studies.

The role of nutraceuticals in prevention and treatment of hypertension: An updated review of the literature

Hypertension (HTN) is a worldwide epidemic in both developed and developing countries. It is one of the leading causes of major health problems such as cardiovascular disease, stroke, and heart attack. In recent years, several studies have reported associations between specific dietary ingredients and improving HTN. Nutraceuticals are natural food components with pharmacological properties. Reports suggest that functional foods and nutraceutical ingredients might support patients to obtain the desired therapeutic blood pressure (BP) goals and reduce cardiovascular risks by modulating various risk factors such as oxidative stress, renin-angiotensin system hyperactivity, inflammation, hyperlipidemia, and vascular resistance. We review the recent clinical experiments that have evaluated the biological and pharmacological activities of several types of nutraceuticals, including sour tea, cocoa, common spices, vitamin C, vitamin E, lycopene, flavonoids, coenzyme Q10, milk's tripeptides, calcium, magnesium, polyunsaturated fatty acids, and prebiotics in preventing and treating HTN. This review summarizes recent knowledge about the impact of common nutraceuticals for the regulation of BP.

Potential Therapeutic Targets of Quercetin and Its Derivatives: Its Role in the Therapy of Cognitive Impairment

Quercetin (QC) is a flavonoid and crucial bioactive compound found in a variety of vegetables and fruits. In preclinical studies, QC has demonstrated broad activity against several diseases and disorders. According to recent investigations, QC is a potential therapeutic candidate for the treatment of nervous system illnesses because of its protective role against oxidative damage and neuroinflammation. QC acts on several molecular signals, including ion channels, neuroreceptors, and inflammatory receptor signaling, and it also regulates neurotrophic and anti-oxidative signaling molecules. While the study of QC in neurological disorders has focused on numerous target molecules, the role of QC on certain molecular targets such as G-protein coupled and nuclear receptors remains to be investigated. Our analysis presents several molecular targets of QC and its derivatives that demonstrate the pharmacological potential against cognitive impairment. Consequently, this article may guide future studies using QC and its analogs on specific signaling molecules. Finding new molecular targets of QC and its analogs may ultimately assist in the treatment of cognitive impairment.

miR-1 induces endothelial dysfunction in rat pulmonary arteries

Endothelial dysfunction plays a central role in the pathophysiology of pulmonary arterial hypertension (PAH). MicroRNAs (miRNAs) are small single-strand and non-coding RNAs that negatively regulate gene function by binding to the 3'-untranslated region (3'-UTR) of specific mRNAs. microRNA-1 (miR-1) is upregulated in plasma from idiopathic PAH patients and in lungs from an experimental model of PAH. However, the role of miRNA-1 on endothelial dysfunction is unknown. The aim of this study was to analyze the effects of miR-1 on endothelial function in rat pulmonary arteries (PA). Endothelial function was studied in PA from PAH or healthy animals and mounted in a wire myograph. Some PA from control animals were transfected with miR-1 or scramble miR. Superoxide anion production by miR-1 was quantified by dihydroethidium (DHE) fluorescence in rat PA smooth muscle cells (PASMC). Bioinformatic analysis identified superoxide dismutase-1 (SOD1), connexin-43 (Cx43), caveolin 2 (CAV2) and Krüppel-like factor 4 (KLF4) as potential targets of miR-1. The expression of SOD1, Cx43, CAV2, and KLF4 was determined by qRT-PCR and western blot in PASMC. PA incubated with miR-1 presented decreased endothelium-dependent relaxation to acetylcholine. We also found an increase in the production of O₂^- and decreased expression of SOD1, Cx43, CAV2, and KLF4 in PASMC induced by miR-1, which may contribute to endothelial dysfunction. In conclusion, these data indicate that miR-1 induces endothelial dysfunction, suggesting a pathophysiological role in PAH.

Autophagy and its role in pulmonary hypertension

Pulmonary hypertension (PH) is a very common kind of pulmonary vascular disease, which can cause a heavier burden on patient's quality of life, even lead to death. Yet, the mechanism of PH is incomprehensive and not so clear nowadays. In recent years, more and more studies show that autophagy plays a pivotal role in the development of PH. Some modalities target on the formation or maturation of autophagosome that has emerged from our increasing knowledge of autophagy machinery, which may prevent or eliminate the process of PH. The deciphering of molecular selectivity of autophagy has also been a source of novel modulators that act specifically on selective forms of autophagy. Tremendous recent progress has opened a new possibility for modulating autophagy in complex diseases. Thus, autophagy may become a prospective choice for treatment of PH. Herein, we reviewed the literatures and discussed the role of autophagy in the development and treatment of PH.

Activation of Kv 7 channels as a novel mechanism for NO/cGMP-induced pulmonary vasodilation

BACKGROUND AND PURPOSE

The NO/cGMP pathway represents a major physiological signalling controlling tone in pulmonary arteries (PA), and drugs activating this pathway are used to treat pulmonary arterial hypertension. K_v channels expressed in PA smooth muscle cells (PASMCs) are key determinants of vascular tone. We aimed to analyse the contribution of K_v 1.5 and K_v 7 channels in the electrophysiological and vasodilating effects evoked by NO donors and the GC stimulator riociguat in PA.

EXPERIMENTAL APPROACH

K_v currents were recorded in isolated rat PASMCs using the patch-clamp technique. Vascular reactivity was assessed in a wire myograph.

KEY RESULTS

The NO donors diethylamine NONOate diethylammonium (DEA-NO) and sodium nitroprusside hyperpolarized the membrane potential and induced a bimodal effect on K_v currents (augmenting the current between -40 and -10 mV and decreasing it at more depolarized potentials). The hyperpolarization and the enhancement of the current were suppressed by K_v 7 channel inhibitors and by the GC inhibitor ODQ but preserved when K_v 1.5 channels were inhibited. Additionally, DEA-NO enhanced K_v 7.5 currents in COS7 cells expressing the KCNQ5 gene. Riociguat increased K_v currents at all potentials ≥-40 mV and induced membrane hyperpolarization. Both effects were prevented by K_v 7 inhibition. Likewise, PA relaxation induced by NO donors and riociguat was attenuated by K_v 7 inhibitors.

CONCLUSIONS AND IMPLICATIONS

NO donors and riociguat enhance K_v 7 currents, leading to PASMC hyperpolarization. This mechanism contributes to NO/cGMP-induced PA vasodilation. Our study identifies K_v 7 channels as a novel mechanism of action of vasodilator drugs used in the treatment of pulmonary arterial hypertension.

Chrysin ameliorates ANTU-induced pulmonary edema and pulmonary arterial hypertension via modulation of VEGF and eNOs

Alpha-naphthylthiourea (ANTU), a rodenticide induces lung toxicity. Chrysin a flavonoid possesses antioxidant, anti-inflammatory, and antihypertensive potential. The aim of this study was to evaluate the efficacy of chrysin against ANTU-induced pulmonary edema (PE) and pulmonary arterial hypertension (PAH) in laboratory rats. Sprague-Dawley rats were used to induce PE (ANTU, 10 mg/kg, ip) and PAH (ANTU, 5 mg/kg, ip, 4 weeks). Animals were treated with chrysin (10, 20, and 40 mg/kg) and various biochemical, molecular, and histological parameters were evaluated. Acute administration of ANTU induces PE revealed by significant (P < 0.05) increase in relative lung weight, pleural effusion volume, lung edema, bronchoalveolar lavage fluid cell counts, total protein, 5-hydroxytryptamine (5-HT), lactate dehydrogenase (LDH), and γ-glutamyl transferase (GGT), whereas pretreatment with chrysin (20 and 40 mg/kg, ip) significantly (P < 0.05) attenuated these ANTU-induced biochemical and histological alterations. Repeated administration of ANTU caused induction of PAH evaluated by significant (P < 0.05) alterations in electrocardiographic, hemodynamic changes, and left ventricular function, whereas chrysin (20 and 40 mg/kg, p.o.) treatment significantly (P < 0.05) attenuated these alterations. ANTU-induced hematological and serum biochemical (aspartate transaminase, alanine transaminase, LDH, and creatinine kinase MB) alterations were significantly (P < 0.05) inhibited by chrysin. It also significantly (P < 0.05) decreased elevated levels of oxido-nitrosative stress in the right ventricle (RV) and lung. Chrysin significantly (P < 0.05) attenuated downregulated endothelial nitric oxide synthase and upregulated vascular endothelial growth factor messenger RNA and protein expressions both in the RV and pulmonary artery. Chrysin inhibited ANTU-induced PE and PAH via modulation of inflammatory responses (5-HT, LDH, and GGT), oxido-nitrosative stress, and VEGF and eNOs levels.

The IRE1α-XBP1 pathway function in hypoxia-induced pulmonary vascular remodeling, is upregulated by quercetin, inhibits apoptosis and partially reverses the effect of quercetin in PASMCs

Hypoxia is a common cause of pulmonary vascular remodeling and endoplasmic reticulum stress (ERS). Upon ER stress, the unfolded protein response (UPR) which activates the IRE1α, PERK and ATF6 signaling pathways is activated to cope with ERS in mammalian cells; however, the role of the three UPR arms in pulmonary vascular remodeling has not been defined. The present study showed that GRP78, a marker of ERS, was upregulated in hypoxic pulmonary artery smooth muscle cells (PASMCs). Among the three arms of the UPR, the IRE1α pathway was noticeably upregulated in hypoxic PASMCs. An inhibitor of IRE1α/XBP1 pathway, 4u8c, inhibited hypoxia-induced cell proliferation and migration and increased cell apoptosis by downregulating PCNA and MMP9 and activating mitochondrial apoptosis by enhancing the expression of BAX, activating caspase-9 and caspase-3, and eventually cleaving PARP. Quercetin affects ERS in many cell types and was shown to relieve hypoxic pulmonary hypertension (HPH) in our previous study. We demonstrated that quercetin evoked excessive GRP78 expression in hypoxic PASMCs compared with hypoxia alone by evaluating the expression of GRP78. The expression of IRE1α and XBP1s, a cleavage form of XBP1u, was upregulated by quercetin in a dose-dependent manner. Pretreatment with 4u8c reversed the apoptosis-promoting effect of quercetin by inhibiting mitochondrial apoptosis. However, 4u8c amplified the effect of quercetin on proliferation and migration in hypoxic PASMCs. In conclusion, the study demonstrated that the IRE1α-XBP1 pathway is involved in the process of hypoxia-induced pulmonary vascular remodeling; 4u8c could restrain hypoxia-induced cell proliferation and migration and reverse the hypoxia-induced apoptosis arrest, while quercetin excited excessive ERS and the IRE1α pathway in hypoxic PASMCs and promoted apoptosis. Our data suggest that intervening the IRE1α-XBP1 pathway may be useful for hypoxia-induced pulmonary arterial hypertension therapy.

miR-1 is increased in pulmonary hypertension and downregulates Kv1.5 channels in rat pulmonary arteries

KEY POINTS

The expression of miR-1 is increased in lungs from the Hyp/Su5416 PAH rat model. Pulmonary artery smooth muscle cells from this animal model are more depolarized and show decreased expression and activity of voltage-dependent potassium channel (Kv)1.5. miR-1 directly targets Kv1.5 channels, reduces Kv1.5 activity and induces membrane depolarization. Antagomir-1 prevents Kv1.5 channel downregulation and the depolarization induced by hypoxia/Su5416 exposition.

ABSTRACT

Impairment of the voltage-dependent potassium channel (Kv) plays a central role in the development of cardiovascular diseases, including pulmonary arterial hypertension (PAH). MicroRNAs are non-coding RNAs that regulate gene expression by binding to the 3'-untranslated region region of specific mRNAs. The present study aimed to analyse the effects of miR-1 on Kv channel function in pulmonary arteries (PA). Kv channel activity was studied in PA from healthy animals transfected with miR-1 or scrambled-miR. Kv currents were studied using the whole-cell configuration of the patch clamp technique. The characterization of the Kv1.5 currents was performed with the selective inhibitor DPO-1. miR-1 expression was increased and Kv1.5 channels were decreased in lungs from a rat model of PAH induced by hypoxia and Su5416. miR-1 transfection increased cell capacitance, reduced Kv1.5 currents and induced membrane depolarization in isolated pulmonary artery smooth muscle cells. A luciferase reporter assay indicated that KCNA5, which encodes Kv1.5 channels, is a direct target gene of miR-1. Incubation of PA with Su5416 and hypoxia (3% O2 ) increased miR-1 and induced a decline in Kv1.5 currents, which was prevented by antagomiR-1. In conclusion, these data indicate that miR-1 induces pulmonary artery smooth muscle cell hypertrophy and reduces the activity and expression of Kv channels, suggesting a pathophysiological role in PAH.

Elevated pulmonary arterial pressure in Zucker diabetic fatty rats

Diabetes is a very strong predictor of chronic systemic vascular diseases and acute cardiovascular events. Recently, associations between metabolic disorders and pulmonary hypertension have also been reported in both humans and animal models. In order to get some further insight into the relationship of pulmonary hypertension with obesity, insulin resistance and hyperglycemia, herein we have used the Zucker diabetic fatty rats (ZDF/clr-lepr fa) at 20 weeks fed a standard diet and compared to their lean Zucker littermates (ZL). ZDF rats were obese, had elevated plasma glucose levels and insulin resistance, i.e. a clinically relevant model of type 2 diabetes. They presented elevated systolic, diastolic and mean pulmonary arterial pressures and a parallel increase in the Fulton index. Systemic arterial pressures were also increased but the left ventricle plus septum weight was similar in both groups and the heart rate was reduced. Wall media thickening was observed in the small pulmonary arteries from the ZDF rats. Isolated pulmonary arteries mounted in a wire myograph showed similar vasoconstrictor responses to phenylephrine and 5-HT and similar responses to the endothelium-dependent vasodilator acetylcholine. However, the iNOS inhibitor 1400W enhanced the vasoconstrictor responses in ZDF but not in ZL rats. The protein expression of eNOS and iNOS was not significantly different in the lungs of the two groups. The lung expression of Bmpr2 mRNA was downregulated. However, the mRNA expression of Kcna5, Kcnk3, Kcnq1, Kcnq4 or Kcnq5, which encode for the potassium channels Kv1.5, TASK-1, Kv7.1, Kv7.4 and Kv7.5, respectively, was similar in ZL and ZDF rats. In conclusion, ZDF rats show increased pulmonary arterial pressure, right ventricular hypertrophy, pulmonary arterial medial thickening and downregulated lung Bmpr2 despite leptin resistance. These changes were mild but are consistent with the view that diabetes is a risk factor for pulmonary hypertension.

Pharmacological Effect of Quercetin in Hypertension and Its Potential Application in Pregnancy-Induced Hypertension: Review of In Vitro, In Vivo, and Clinical Studies

Since improving maternal and child health is a public health priority worldwide, the main aim of treatment of hypertension in pregnant women is to prevent complications during pregnancy, labor, and postpartum. In consequence, much attention is paid to the use of antihypertensive drugs that can be used safely during pregnancy. Several side effects of methyldopa, which is currently the most commonly used antihypertensive drug in pregnant women, mean that the search for an effective and safe alternative still continues. Flavonoid compounds present in medicinal plants, vegetables, and fruits may be a promising source of new drugs. In this aspect, quercetin, a well-known flavonoid due to its antihypertensive action, may be considered a prototype for safe antihypertensive drugs. This review focuses on the selective activity of quercetin. Based on recent studies, a few problems were discussed, including (1) pathology of pregnancy-induced hypertension; (2) search for new pharmacological treatments of pregnancy-induced hypertension; (3) issues with the use of herbal extracts during pregnancy; (4) flavonoids as natural active chemical compounds; (5) quercetin: its action during pregnancy, in vitro and in vivo pharmacological activities, clinical trials, and meta-analysis; (6) quercetin intake during pregnancy; (7) other natural compounds tested during pregnancy; (8) potential problems with the use of quercetin; (9) safety profile of quercetin. Various studies have shown a beneficial effect of quercetin on vascular endothelial function and its antioxidative and anti-inflammatory activity on cellular and tissue level. It is known that in animal models quercetin affects positively the development of embryo, fetus, and placenta. Because this flavonoid did not have teratogenic and abortive effect, it is generally recognized as safe. For this reason it should be appreciated and studied in the aspect of its potential use in the prevention and treatment of pregnancy-induced hypertension among women in this risk group.

HIV transgene expression impairs K+ channel function in the pulmonary vasculature

Human immunodeficiency virus (HIV) infection is an established risk factor for pulmonary arterial hypertension (PAH); however, the pathogenesis of HIV-related PAH remains unclear. Since K⁺ channel dysfunction is a common marker in most forms of PAH, our aim was to analyze whether the expression of HIV proteins is associated with impairment of K⁺ channel function in the pulmonary vascular bed. HIV transgenic mice (Tg26) expressing seven of the nine HIV viral proteins and wild-type (WT) mice were used. Hemodynamic assessment was performed by echocardiography and catheterization. Vascular reactivity was studied in endothelium-intact pulmonary arteries. K⁺ currents were recorded in freshly isolated pulmonary artery smooth muscle cells (PASMC) using the patch-clamp technique. Gene expression was assessed using quantitative RT-PCR. PASMC from Tg26 mice had reduced K⁺ currents and were more depolarized than those from WT. Whereas voltage-gated K⁺ channel 1.5 (Kv1.5) currents were preserved, pH-sensitive noninactivating background currents ( I_KN) were nearly abolished in PASMC from Tg26 mice. Tg26 mice had reduced lung expression of Kv7.1 and Kv7.4 channels and decreased responses to the Kv7.1 channel activator L-364,373 assessed by vascular reactivity and patch-clamp experimental approaches. Although we found pulmonary vascular remodeling and endothelial dysfunction in Tg26 mice, this was not accompanied by changes in hemodynamic parameters. In conclusion, the expression of HIV proteins in vivo impairs pH-sensitive I_KN and Kv7 currents. This negative impact of HIV proteins in K⁺ channels was not sufficient to induce PAH, at least in mice, but may play a permissive or accessory role in the pathophysiology of HIV-associated PAH.

Pulmonary Arterial Hypertension Affects the Rat Gut Microbiome

We have analysed whether pulmonary arterial hypertension (PAH) alters the rat faecal microbiota. Wistar rats were injected with the VEGF receptor antagonist SU5416 (20 mg/kg s.c.) and followed for 2 weeks kept in hypoxia (10% O₂, PAH) or injected with vehicle and kept in normoxia (controls). Faecal samples were obtained and microbiome composition was determined by 16S rRNA gene sequencing and bioinformatic analysis. No effect of PAH on the global microbiome was found (α- or β-diversity). However, PAH-exposed rats showed gut dysbiosis as indicated by a taxonomy-based analysis. Specifically, PAH rats had a three-fold increase in Firmicutes-to-Bacteroidetes ratio. Within the Firmicutes phylum, there were no large changes in the relative abundance of the bacterial families in PAH. Among Bacteroidetes, all families were less abundant in PAH. A clear separation was observed between the control and PAH clusters based on short chain fatty acid producing bacterial genera. Moreover, acetate was reduced in the serum of PAH rats. In conclusion, faecal microbiota composition is altered as a result of PAH. This misbalanced bacterial ecosystem might in turn play a pathophysiological role in PAH by altering the immunologic, hormonal and metabolic homeostasis.

Potential interactions among phenolic compounds and probiotics for mutual boosting of their health-promoting properties and food functionalities - A review

Several foods are rich sources of phenolic compounds (PC) and their beneficial effects on human health may be increased through the action of probiotics. Additionally, probiotics may use PC as substrates, increasing their survival and functionality. This review presents available studies on the effects of PC on probiotics, including their physiological functionalities, interactions and capability of surviving during exposure to gastrointestinal conditions and when incorporated into food matrices. Studies have shown that PC can improve the adhesion capacity and survival of probiotics during exposure to conditions that mimic the gastrointestinal tract. There is strong evidence that PC can modulate the composition of the gut microbiota in hosts, improving a variety of biochemical markers and risk factors for chronic diseases. Available literature also indicates that metabolites of PC formed by intestinal microorganisms, including probiotics, exert a variety of benefits on host health. These metabolites are typically more active than parental dietary PC. The presence of PC commonly enhances probiotic survival in different foods. Finally, further clinical studies need to be developed to confirm in vitro and experimental findings concerning the beneficial interactions among different PC and probiotics.

Effect of Free and Nanoencapsulated Copaiba Oil on Monocrotaline-induced Pulmonary Arterial Hypertension

Copaiba oil comes from an Amazonian tree and has been used as an alternative medicine in Brazil. However, it has not been investigated yet in the treatment of cardiovascular diseases. This study was designed to test whether copaiba oil or nanocapsules containing this oil could modulate monocrotaline (MCT)-induced pulmonary arterial hypertension (PAH). Male Wistar rats (170 ± 20 g) received oil or nanocapsules containing this oil (400 mg/kg) by gavage daily for 1 week. At the end of this period, a single injection of MCT (60 mg/kg i.p.) was administered and measurements were performed after 3 weeks. The animals were divided into 6 groups: control, copaiba oil, nanocapsules with copaiba oil, MCT, oil + MCT, and nanocapsules + MCT. Afterward, echocardiographic assessments were performed, and rats were killed to collect hearts for morphometry and oxidative stress. MCT promoted a significant increase in pulmonary vascular resistance, right ventricle (RV) hypertrophy, and RV oxidative stress. Both oil and copaiba nanocapsules significantly reduced RV hypertrophy and oxidative stress. Pulmonary vascular resistance was reduced by copaiba oil in natura but not by nanocapsules. In conclusion, copaiba oil seems to offer protection against MCT-induced PAH. Our preliminary results suggest that copaiba oil may be an important adjuvant treatment for PAH.

The administration of surfactant decreased oxidative stress in lungs of mice exposed to cigarette smoke

The alveolar surfactant, which composition consists of a unique and complex mixture of lipids and proteins, has immunomodulatory action. This study aimed to evaluate the effects of exogenous surfactant on pulmonary inflammatory response in mice exposed to cigarette smoke (CS). Twenty-four mice C57BL/6 were divided into four groups: control group exposed to ambient air (CG); surfactant treated group (SG); CS exposed group (CSG) and CS exposed group treated with surfactant (CSSG). For five days, CSG and CSSG were exposed to 12 commercial cigarettes/day and SG and CSSG received the surfactant by intranasal instillation. At the end of the experiment, the animals were euthanatized for the collection of bronchoalveolar lavage fluid (BALF) and lungs. The total number of leukocytes in BALF increased in CSG compared to CG, however, there was a decrease in CSSG compared to CSG. There was an increase in lipid peroxidation in SG and CSG compared to CG while there was a decrease in CSSG compared to CSG. Regarding the antioxidant enzymes, the catalase (CAT) activity increased in all groups compared to CG and the superoxide dismutase (SOD) activity decreased in CSG compared to the CG and SG. There was an increase in TNF in SG, CSG and CSSG compared to CG. There was an increase in IL-17 in CSSG compared to CG. There was an increase in CCL5 in SG and CSSG compared to CG. Therefore, our results demonstrated that the administration of exogenous surfactant was able to decrease the oxidative processes in the lungs of mice induced by short-term exposure to CS.

Peroxiredoxin-2 plays a pivotal role as multimodal cytoprotector in the early phase of pulmonary hypertension

Pulmonary-artery-hypertension (PAH) is a life-threatening and highly invalidating chronic disorder. Chronic oxidation contributes to lung damage and disease progression. Peroxiredoxin-2 (Prx2) is a typical 2-cysteine (Cys) peroxiredoxin but its role on lung homeostasis is yet to be fully defined. Here, we showed that Prx2^-/- mice displayed chronic lung inflammatory disease associated with (i) abnormal pulmonary vascular dysfunction; and (ii) increased markers of extracellular-matrix remodeling. Hypoxia was used to induce PAH. We focused on the early phase PAH to dissect the role of Prx2 in generation of PAH. Hypoxic Prx2^-/-mice showed (i) amplified inflammatory response combined with cytokine storm; (ii) vascular activation and dysfunction; (iii) increased PDGF-B lung levels, as marker of extracellular-matrix deposition and remodeling; and (iv) ER stress with activation of UPR system and autophagy. Rescue experiments with in vivo the administration of fused-recombinant-PEP-Prx2 show a reduction in pulmonary inflammatory vasculopathy and in ER stress with down-regulation of autophagy. Thus, we propose Prx2 plays a pivotal role in the early stage of PAH as multimodal cytoprotector, targeting oxidation, inflammatory vasculopathy and ER stress with inhibition of autophagy. Collectively, our data indicate that Prx2 is able to interrupt the hypoxia induced vicious cycle involving oxidation-inflammation-autophagy in the pathogenesis of PAH.

Bidens pilosa Ethylene acetate extract can protect against L-NAME-induced hypertension on rats

BACKGROUND

Essential hypertension is mainly caused by endothelial dysfunction which results from nitric oxide (NO) deficiency. The present study was design to evaluate the protective effect of Bidens pilosa ethylene acetate extract (Bp) on L-NAME induced hypertension and oxidative stress in rats.

METHODS

Male Wistar rats were used to induce hypertension by the administration of L-NAME (a non-pecific nitric oxide inhibitor) (50 mg/kg/day). The others groups were receiving concomitantly L-NAME plus Bp extract (75 and 150 mg/kg/day) or losartan (25 mg/kg/day). All the treatments were given orally for 4 weeks. At the end of the treatment, the hemodynamic parameters were recorded using the direct cannulation method. The effects of the extract on lipid profile, kidney and liver functions as well as oxidative stress markers were evaluated by colorimetric method. Results were expressed as the mean ± SEM. The difference between the groups was compared using one-way analysis of variance (ANOVA) followed by the Duncan's post hoc test.

RESULTS

Animals receiving L-NAME presented high blood pressure, normal heart rate and lipid profile as well as NO depletion, liver and kidney injuries and oxidative stress. The concomitant treatment with L-NAME and Bp or losartan succeeded to prevent the raised of blood pressure and all the other injuries without affecting the heart rate.

CONCLUSION

These results confirm the antihypertensive effects of Bidens pilosa and highlight its protective properties in L-NAME model of hypertension in rat, probably due to the presence of Quercetin 3,3 '-dimethyl ether 7-0-β-D-glucopyranoside.

Effects of phyto-oestrogen quercetin on productive performance, hormones, reproductive organs and apoptotic genes in laying hens

Quercetin, a polyphenolic flavonoid with diverse biological activities including anti-inflammatory and antiviral, inhibits lipid peroxidation, prevents oxidative injury and cell death. The purpose of the research was to investigate the effect of quercetin on productive performance, reproductive organs, hormones and apoptotic genes in laying hens between 37 and 45 weeks of age, because of the structure and oestrogenic activities similar to 17β-oestradiol. The trial was conducted using 240 Hessian laying hens (37 weeks old), housed in wire cages with two hens in each cage. These hens were randomly allotted to four treatments with six replicates, 10 hens in each replicate and fed with diets containing quercetin as 0, 0.2, 0.4 and 0.6 g/kg feed for 8 weeks. The results showed that dietary quercetin significantly increased (p < .05) the laying rate and was higher in group supplemented with 0.4 g/kg, and feed-egg ratio was decreased (p < .05) by quercetin. Dietary quercetin has no effect (p > .05) on average egg weight and average daily feed intake. Compared with control, secretion of hormones, oestradiol (E₂ )_, progesterone (P4), follicle-stimulating hormone (FSH), luteinizing hormone (LH), insulin-like growth factors-1 (IGF-1) and growth hormone (GH), was found to be significantly higher (p < .05) in quercetin-supplemented groups. Also ovary index, uterus index and oviduct index were not significantly influenced (p > .05) by quercetin, whereas magnum index, isthmus index, magnum length, isthmus length and follicle numbers were significantly increased (p < .05) with quercetin supplementation. Additionally, expression of apoptotic genes was significantly (p < .05) up-regulated or down-regulated by quercetin. These results indicated that quercetin improved productive performance, and its mechanism may be due to the oestrogen-like activities of quercetin.

Quercetin induces autophagy via FOXO1-dependent pathways and autophagy suppression enhances quercetin-induced apoptosis in PASMCs in hypoxia

Quercetin, an important dietary flavonoid has been demonstrated to potentially reverse or even prevent pulmonary arterial hypertension (PAH) progression. However, the effects of quercetin on apoptosis and autophagy in pulmonary arterial smooth muscle cells (PASMCs) have not yet been clearly elucidated. The current study found that quercetin significantly induce the apoptotic and autophagic capacities of PASMCs in vitro and in vivo in hypoxia. In addition, we found that quercetin increases FOXO1 (a major mediator in autophagy regulation) expression and transcriptional activity. Moreover, FOXO1 knockdown by siRNAs inhibited the phosphorylation of mTOR and 4E-BPI, which is downstream of P70-S6K, and markedly blocked quercetin-induced autophagy. We also observed that FOXO1-mediated autophagy was achieved via SESN3 not Rictor upregulation and after mTOR suppression. Furthermore, Treatment with autophagy-specific inhibitors could markedly enhance quercetin-induced apoptosis in PASMCs under hypoxia. Finally, quercetin in combination with autophagy inhibition treatment could enhance the therapeutic effects of quercetin in hypoxia-associated PAH in vivo. Taken together, quercetin could enhance hypoxia-induced autophagy through the FOXO1-SENS3-mTOR pathway in PASMCs. Combining quercetin and autophagy inhibitors may be a novel therapeutic strategy for treating hypoxia-associated PAH.