Pulmonary arterial hypertension (PAH) is a severe cardiovascular disease that can lead to vascular remodelling and hypertension. Clinical diagnosis of PAH is very difficult. Uric acid (UA) can act as a biological marker for screening of PAH in patients. Multiple studies have indicated that reactive oxygen species (ROS) play an important role in the development of PAH. Thus, it is important to study the relationship between UA and ROS based on the pathogenesis of PAH. For monitoring PAH, a high performance liquid chromatography-electrospray ionization-tandem mass spectrometry (HPLC-ESI-MS/MS) method was developed to measure the concentration of UA from rat models and pulmonary arterial endothelial cells (PAECs) models, which were induced by monocrotaline (MCT) and hypoxia, respectively. In addition, the treatment groups were treated by N-acetyl-L-cysteine (NAC), a ROS scavenger. With the confirmation from hematoxylin-eosin (H&E) staining, the HPLC-ESI-MS/MS method was adopted to successfully analyze the concentration of UA. In this study, for the first time, thymine was used as an internal standard (I.S.) of uric acid. The results showed that the UA concentration in the PAH groups was higher than that in the normal groups, while the UA concentration in the treatment groups decreased compared to that in the PAH group (p < 0.05). It was experimentally proven that the HPLC-ESI-MS/MS method is a rapid, efficient and reliable quantitative method to detect PAH. Furthermore, our results indicated that UA and ROS have a double-regulator role.

Reactive oxygen species (ROS) are involved in the pathologic process of pulmonary arterial hypertension as either mediators or inducers. Rutin is a type of flavonoid which exhibits significant scavenging properties on oxygen radicals both in vitro and in vivo. In this study, we proposed that rutin attenuated hypoxia-induced pulmonary artery smooth muscle cell (PASMC) proliferation by scavenging ROS. Immunofluorescence data showed that rutin decreased the production of ROS, which was mainly generated through mitochondria and NADPH oxidase 4 (Nox4) in pulmonary artery endothelial cells (PAECs). Western blot results provided further evidence on rutin increasing expression of Nox4 and hypoxia-inducible factor-1α (HIF-1α). Moreover, cell cycle analysis by flow cytometry indicated that proliferation of PASMCs triggered by hypoxia was also repressed by rutin. However, N-acetyl-L-cysteine (NAC), a scavenger of ROS, abolished or diminished the capability of rutin in repressing hypoxia-induced cell proliferation. These data suggest that rutin shows a potential benefit against the development of hypoxic pulmonary arterial hypertension by inhibiting ROS, subsequently preventing hypoxia-induced PASMC proliferation.

Phyllanthi Fructus (PF) is a valuable botanical resource with a long history of traditional use, known for potent antioxidant and anti-inflammatory effects attributed to its rich contents of bioactive compounds, particularly polyphenols. However, current extraction techniques limit the utilization of polyphenols from PF. This study aimed to achieve the maximum polyphenol yield and improve the antioxidant activity of PF extracts to promise PF's prospects for modern healthcare. Firstly, ultrasonic-assisted extraction (UAE) was employed to extract the polyphenols in PF and a combination of Plackett-Burman designs (PBD) and response surface methodology (RSM) was applied to optimize UAE's conditions. Next, cellular superoxide dismutase (SOD) and malondialdehyde (MDA) were used to assess the antioxidant activity of extracted polyphenols. Ultra-Performance Liquid Chromatography coupled with Quadrupole Time-of-Flight Mass Spectrometry (UPLC-Q-TOF MS) was utilized to characterize polyphenol components in the PF extracts. Finally, network pharmacology and molecular docking analysis were performed to screen the potential target proteins of polyphenols from PF. As a result, the optimized polyphenol yield was 213.49 mg/g, and the antioxidant activities, measured by ability of DPPH scavenging, ABTS+ scavenging, and FRAP were 76.95 %, 2.24 mmol/g, 2.34 mmol/g, respectively. PF extracts also showed good antioxidant capabilities at cellular level. 26 polyphenol components were identified in the PF extracts. Among these, ellagic acid, myricetin, and eriodictyol may exert antioxidant effects by interacting with AKT serine/threonine kinase 1 (AKT1). In conclusion, our study provides valuable insights into the optimizing PF extraction and underscores its potential applications in enhancing natural polyphenols extraction using UAE with a combination of PBD and RSM. These findings offer a promising avenue for the development and utilization of PF, and could serve as a reference for similar extraction processes in the future.

We previously reported that 15-lipoxygenase (15-LO) and its metabolite 15-hydroxyeicosatetraenoic acid (15-HETE) were up-regulated in pulmonary arterial cells from both pulmonary artery hypertension patients and hypoxic rats and that these factors mediated the progression of pulmonary hypertension (PH) by affecting the proliferation and apoptosis of pulmonary arterial (PA) cells. However, the underlying mechanisms of the remodeling induced by 15-HETE have remained unclear. As reactive oxygen species (ROS) and 15-LO are both induced by hypoxia, it is possible that ROS are involved in the events of hypoxia-induced 15-LO expression that lead to PH. We employed immunohistochemistry, tube formation assays, bromodeoxyuridine (BrdU) incorporation assays, and cell cycle analyses to explore the role of ROS in the process of 15-HETE-mediated hypoxic pulmonary hypertension (HPH). We found that exogenous 15-HETE facilitated the generation of ROS and that this effect was mainly localized to mitochondria. In particular, the mitochondrial electron transport chain and nicotinamide-adenine dinucleotide phosphate oxidase 4 (Nox4) were responsible for the significant 15-HETE-stimulated increase in ROS production. Moreover, ROS induced by 15-HETE stimulated endothelial cell (EC) migration and promoted pulmonary artery smooth muscle cell (PASMC) proliferation under hypoxia via the p38 MAPK pathway. These results indicated that 15-HETE-regulated ROS mediated hypoxia-induced pulmonary vascular remodeling (PVR) via the p38 MAPK pathway.

Pulmonary arterial hypertension (PAH) is a progressive disease that significantly endangers human health, where metabolism may drive pathogenesis: a shift from mitochondrial oxidation to glycolysis occurs in diseased pulmonary vessels and the right ventricle. An increase in pulmonary vascular resistance in patients with heart failure with a preserved ejection fraction portends a poor prognosis. Luteolin exists in numerous foods and is marketed as a dietary supplement assisting in many disease treatments. However, little is known about the protective effect of luteolin on metabolism disorders in diseased pulmonary vessels. In this study, we found that luteolin apparently reversed the pulmonary vascular remodeling of PAH rats by inhibiting the abnormal proliferation of pulmonary artery smooth muscle cells (PASMCs). Moreover, network pharmacology and metabolomics results revealed that the arachidonic acid pathway, amino acid pathway and TCA cycle were dysregulated in PAH. A total of 14 differential metabolites were significantly changed during the PAH, including DHA, PGE2, PGD2, LTB4, 12-HETE, 15-HETE, PGF2α, and 8-iso-PGF2α metabolites in the arachidonic acid pathway, and L-asparagine, oxaloacetate, N-acetyl-L-ornithine, butane diacid, ornithine, glutamic acid metabolites in amino acid and TCA pathways. However, treatment with luteolin recovered the LTB4, PGE2, PGD2, 12-HETE, 15-HETE, PGF2α and 8-iso-PGF2α levels close to normal. Meanwhile, we showed that luteolin also downregulated the gene and protein levels of COX 1, 5-LOX, 12-LOX, and 15-LOX in the arachidonic acid pathway. Collectively, this work highlighted the metabolic mechanism of luteolin-protected PAH and showed that luteolin would hold great potential in PAH prevention.