Fasudil reversed MCT-induced and chronic hypoxia-induced pulmonary hypertension by attenuating oxidative stress and inhibiting the expression of Trx1 and HIF-1α

Biomimetic Nanoparticle-Mediated Target Delivery of Hypoxia-Responsive Plasmid of Angiotensin-Converting Enzyme 2 to Reverse Hypoxic Pulmonary Hypertension

Hypoxic pulmonary hypertension (HPH) is characterized by pulmonary vascular sustained constriction and progressive remodeling, which are initiated by hypoxia then with hypoxia-induced additive factors including pulmonary vascular endothelium injury, intrapulmonary angiotension system imbalance, and inflammation. Now HPH is still an intractable disease lacking effective treatments. Gene therapy has a massive potential for HPH but is hindered by a lack of efficient targeted delivery and hypoxia-responsive regulation systems for transgenes. Herein, we constructed the hypoxia-responsive plasmid of angiotensin-converting enzyme 2 (ACE2) with endothelial-specific promoter Tie2 and a hypoxia response element and next prepared its biomimetic nanoparticle delivery system, named ACE2-CS-PRT@PM, by encapsulating the plasmid of ACE2 with protamine and chondroitin sulfate as the core then coated it with a platelet membrane as a shell for targeting the injured pulmonary vascular endothelium. ACE2-CS-PRT@PM has a 194.3 nm diameter with a platelet membrane-coating core-shell structure and a negatively charged surface, and it exhibits higher delivery efficiency targeting to pulmonary vascular endothelium and hypoxia-responsive overexpression of ACE2 in endothelial cells in a hypoxia environment. In vitro, ACE2-CS-PRT@PM significantly inhibited the hypoxia-induced proliferation of pulmonary smooth muscle cells. In vivo, ACE2-CS-PRT@PM potently ameliorated the hemodynamic dysfunction and morphological abnormality and largely reversed HPH via inhibiting the hypoxic proliferation of pulmonary artery smooth muscle cells, reducing pulmonary vascular remodeling, restoring balance to the intrapulmonary angiotension system, and improving the inflammatory microenvironment without any detectable toxicity. Therefore, ACE2-CS-PRT@PM is promising for the targeted gene therapy of HPH.

Comprehensive Review on Novel Targets and Emerging Therapeutic Modalities for Pulmonary Arterial Hypertension

Pulmonary Arterial Hypertension (PAH) is the progressive increase in mean pulmonary arterial pressure (mPAP) (≥ 20 mmHg at rest). Current treatment strategies include the drugs targeting at nitric oxide pathway, endothelin receptors, prostaglandin receptors, thromboxane receptors and phosphodiesterase inhibitors, which provides the symptomatic relief. Despite of these treatments, the mortality amongst the PAH patients remains high due to non-reversal of the condition. This review primarily covers the introduction of PAH and the current treatments of the disease. This is followed by the newer disease targets expressed in the pathobiology of the disease like Rho Kinase Pathway, Vasoactive Intestinal Peptide Pathway, Receptor Tyrosine Kinases, Serotonin signalling pathway, Voltage-gated potassium (Kv) channel pathway. Newer formulation strategies for targeting at these specific receptors were covered and includes nano formulations like liposomes, Micelles, Polymeric Nanoparticles, Solid Lipid Nanoparticles (SLN), Bioresorbable stents, NONOates, Cell-Based Therapies, miRNA therapy for PAH. Novel targets were identified for their role in the pathogenesis of the PAH and needs to be targeted with new molecules or existing molecules effectively. Nanosystems have shown their potential as alternative carriers on the virtue of their better performance than traditional drug delivery systems.

ROCK Inhibition as Potential Target for Treatment of Pulmonary Hypertension

Pulmonary hypertension (PH) is a cardiovascular disease caused by extensive vascular remodeling in the lungs, which ultimately leads to death in consequence of right ventricle (RV) failure. While current drugs for PH therapy address the sustained vasoconstriction, no agent effectively targets vascular cell proliferation and tissue inflammation. Rho-associated protein kinases (ROCKs) emerged in the last few decades as promising targets for PH therapy, since ROCK inhibitors demonstrated significant anti-remodeling and anti-inflammatory effects. In this review, current aspects of ROCK inhibition therapy are discussed in relation to the treatment of PH and RV dysfunction, from cell biology to preclinical and clinical studies.

Effects of Intermittent Normoxia on Chronic Hypoxic Pulmonary Hypertension and Right Ventricular Hypertrophy in Rats

Liu, Chunlei, Xu Chen, Ge Guo, Xiang Xu, Xin Li, Qingxia Wei, Yanying Shen, Hanlu Li, Jianxiu Hao, Ya Ping Tian, and Kunlun He. Effects of intermittent normoxia on chronic hypoxic pulmonary hypertension and right ventricular hypertrophy in rats. High Alt Med Biol. 22: 184-192, 2021. Background: Individuals with chronically low arterial oxygen tension owing to high altitude develop elevated rates of pulmonary hypertension (PH) and right ventricular (RV) hypertrophy. However, the effects of the frequency and duration of normoxic exposure on PH and RV hypertrophy have not been adequately assessed; thus, we aimed to analyze the same. Materials and Methods: PH and RV hypertrophy were induced in 60 rats using a hypobaric chamber. Of these 60 rats, every 10 were exposed to normoxic conditions for 30 minutes once (1T/D), three times (3T/D), or five times daily (5T/D), or for one 150-minute recovery daily (1LT/D). Furthermore, 10 rats were housed in a normoxic environment, and another 10 were subjected to continuous hypoxia. After 4 weeks, hemodynamic measurements were recorded, and the hearts were harvested for pathomorphological observations. Results: Average pulmonary arterial pressures (PAP) of control rats and those exposed to hypobaric hypoxia were 14.1 and 32.3 mmHg, respectively. After 30 minutes of exposure to normoxia 3T/D, 5T/D, or 1LT/D, PAP values were reduced to 27.1, 27.9, or 26.8 mmHg, respectively. Four weeks of hypoxic exposure elevated the RV/heart weight (HW) ratios, while exposure to normoxia 3T/D, 5T/D, and 1LT/D significantly reduced RV/HW. In addition, exposure to normoxia 3T/D, 5T/D, 1LT/D reduced the percentage wall thickness of the pulmonary artery as well as the hypertrophy indices of atrial natriuretic peptide, brain natriuretic peptide, and myosin heavy chain 7 (MYH-7). Conclusions: Thirty-minute exposure to normoxic conditions of 3T/D, 5T/D, or 1LT/D effectively ameliorates PH and RV thickening.

The alveolar epithelial cells are involved in pulmonary vascular remodeling and constriction of hypoxic pulmonary hypertension

BACKGROUND

Hypoxic pulmonary hypertension (HPH) is a common type of pulmonary hypertension and characterized by pulmonary vascular remodeling and constriction. Alveolar epithelial cells (AECs) primarily sense alveolar hypoxia, but the role of AECs in HPH remains unclear. In this study, we explored whether AECs are involved in pulmonary vascular remodeling and constriction.

METHODS

In the constructed rat HPH model, hemodynamic and morphological characteristics were measured. By treating AECs with hypoxia, we further detected the levels of superoxide dismutase 2 (SOD2), catalase (CAT), reactive oxygen species (ROS) and hydrogen peroxide (H2O2), respectively. To detect the effects of AECs on pulmonary vascular remodeling and constriction, AECs and pulmonary artery smooth cells (PASMCs) were co-cultured under hypoxia, and PASMCs and isolated pulmonary artery (PA) were treated with AECs hypoxic culture medium. In addition, to explore the mechanism of AECs on pulmonary vascular remodeling and constriction, ROS inhibitor N-acetylcysteine (NAC) was used.

RESULTS

Hypoxia caused pulmonary vascular remodeling and increased pulmonary artery pressure, but had little effect on non-pulmonary vessels in vivo. Meanwhile, in vitro, hypoxia promoted the imbalance of SOD2 and CAT in AECs, leading to increased ROS and hydrogen peroxide (H2O2) production in the AECs culture medium. In addition, AECs caused the proliferation of co-cultured PASMCs under hypoxia, and the hypoxic culture medium of AECs enhanced the constriction of isolated PA. However, treatment with ROS inhibitor NAC effectively alleviated the above effects.

CONCLUSION

The findings of present study demonstrated that AECs were involved in pulmonary vascular remodeling and constriction under hypoxia by paracrine H2O2 into the pulmonary vascular microenvironment.

New Insights into the Implication of Mitochondrial Dysfunction in Tissue, Peripheral Blood Mononuclear Cells, and Platelets during Lung Diseases

Lung diseases such as chronic obstructive pulmonary disease, asthma, pulmonary arterial hypertension, or idiopathic pulmonary fibrosis are major causes of morbidity and mortality. Complex, their physiopathology is multifactorial and includes lung mitochondrial dysfunction and enhanced reactive oxygen species (ROS) release, which deserves increased attention. Further, and importantly, circulating blood cells (peripheral blood mononuclear cells-(PBMCs) and platelets) likely participate in these systemic diseases. This review presents the data published so far and shows that circulating blood cells mitochondrial oxidative capacity are likely to be reduced in chronic obstructive pulmonary disease (COPD), but enhanced in asthma and pulmonary arterial hypertension in a context of increased oxidative stress. Besides such PBMCs or platelets bioenergetics modifications, mitochondrial DNA (mtDNA) changes have also been observed in patients. These new insights open exciting challenges to determine their role as biomarkers or potential guide to a new therapeutic approach in lung diseases.

Regulation of hyperglycemia in diabetic mice by autolysates from β-mannanase-treated brewer's yeast

BACKGROUND

Diabetes mellitus is a serious chronic disease, characterized by hyperglycemia. This study administered either β-mannanase-treated yeast cell autolysis supernatant (YCS) or yeast cell-wall residues after autolysis (YCR) to investigate their influence on the alleviation of diabetes in a diabetic mouse model.

RESULTS

Application of either YCS or YCR led to body weight gain, blood glucose reduction, and an improvement in lipid composition in the diabetic mice. Administration of YCS was more effective in inhibiting oxidative stress than YCR. The expression of PPARα and CPT1α was enhanced, improving lipid biosynthesis, and Trx1 and HIF-1-α genes were downregulated due to the activation of thioredoxin following the interventions, indicating that the processes of lipid metabolism and oxidative stress were heavily involved in the reduction of diabetic characteristics following the interventions. The current study revealed that consumption of YCR also led to a reduction in hyperglycemia, this being associated with its richness in mineral elements, such as chromium and selenium.

CONCLUSION

This study may highlight the potential of both YCS and YCR as functional ingredients in dietary formula for improving diabetic syndromes. © 2019 Society of Chemical Industry.

Targeting the RhoA-ROCK pathway to regulate T-cell homeostasis in hypoxia-induced pulmonary arterial hypertension

BACKGROUND

Hypoxic pulmonary arterial hypertension (PAH) is a crippling disease with limited therapeutic methods. The imbalance of T helper 17 cell (Th17)/regulatory T cell (Treg) plays an important role in the development of Hypoxic PAH. However, whether targeting the ras homolog family member A-Rho kinase (RhoA-ROCK) pathway (activation and inhibition) by lysophosphatidic acid (LPA) and fasudil (FSD) regulate T-cell homeostasis in Hypoxic PAH remain unknown.

OBJECTIVE

To examine the effects of LPA and FSD on hypoxic pulmonary vascular remodeling and homeostasis of Th17/Treg cells in Hypoxic PAH.

METHODS

Rats were exposed to hypoxia (10 ± 0.5% O₂) to induce Hypoxic PAH. The experiments consists of two parts. Forty rats were randomly divided into four groups (n = 10): normoxia group, normoxia + LPA group, hypoxia group and hypoxia + LPA group. Thirty rats were randomly divided into another three groups (n = 10): normoxia group, hypoxia group, and hypoxia + FSD group. Rats in normoxia + LPA group and hypoxia + LPA group were intraperitoneally injected 40 μg/kg LPA daily. Rats in hypoxia + FSD group were intraperitoneally injected 30 mg/kg fasudil daily. The effects of LPA and FSD on the development of hypoxic PAH and right ventricle (RV) hypertrophy, on pulmonary vascular remodeling, and on changes of Th17/Treg cells and levels of interleukin-17 (IL-17) and IL-10 were examined.

RESULTS

PAH and RV hypertrophy occurred in rats exposed to hypoxia. LPA exacerbated hypoxic pulmonary vascular remodeling and FSD inhibited it. LPA increased Th17/Treg imbalance in peripheral blood and spleen. However, after treatment with FSD, hypoxic PAH rats showed an obvious reduction of Th17 cells as well as an increase of Treg cells. LPA increased the expression of phosphorylated-signal transducer and activator of transcription 3 (p-STAT3) and reduced the p-STAT5 in peripheral blood and spleen in hypoxic PAH rats. The expression of p-STAT3 and p-STAT5 in hypoxic PAH rats treated with FSD showed opposite changes. LPA increased the expression of IL-17 and reduced the IL-10 in small intrapulmonary arteries and serum in hypoxic PAH. However, the expression of IL-17 and IL-10 in hypoxic PAH rats treated with FSD showed opposite changes.

CONCLUSIONS

Activation and inhibition of RhoA-ROCK pathway by LPA and FSD modulated the homeostasis of Th17/Treg cells via regulating STAT3/STAT5 phosphorylation in hypoxic PAH. Thus, Apart from influence of pulmonary vascular remodeling, regulation of Th17/Treg homeostasis by RhoA-ROCK pathway play a key role in hypoxic PAH.

Effects of Fasudil on Patients with Pulmonary Hypertension Associated with Left Ventricular Heart Failure with Preserved Ejection Fraction: A Prospective Intervention Study

Background

Pulmonary hypertension due to left ventricular heart failure with preserved ejection fraction (PH-HFpEF) is an increasingly medical problem. The aim of the study was to evaluate the clinical efficacy of fasudil on PH-HFpEF elderly patients and to figure out the subtype of PH-HFpEF which may be the therapeutic object of fasudil.

Method

58 PH-HFpEF elderly patients were enrolled. Patients were diagnosed with passive pulmonary hypertension (PPH) or reactive pulmonary hypertension (RPH) by right heart catheterization and all receiving Rho kinase inhibitor fasudil for 2 weeks. The endpoint includes changes in SpO2, NT-pro BNP, cardiac functional classification, and echocardiography measurements after 2 weeks treatment.

Results

The course of disease in the RPH group was longer than the PPH group (p < 0.05). Cardiac output was found to be worse in the RPH group than the PPH group (p < 0.01). Besides, the RPH group demonstrated a greater transpulmonary pressure gradient (TPG) and pulmonary vascular resistance (PVR) than the PPH group (p < 0.01 for both) as well as pulmonary arterial systolic pressure (PASP) and mean pulmonary arterial pressure (mPAP) (p < 0.01 for both), which fits the feature of RPH. After treatment of fasudil, in RPH group, PASP significantly decreased (p < 0.01) with decreased E/E′ and increased E/A (p < 0.05 for both), indicating that pulmonary haemodynamics and cardiac diastolic function were ameliorated, but the measurements in the PPH group had no significant changes. NT-pro BNP and 6 MWD of both groups were improved (p < 0.05). The total effective rate of the RPH group was 74.29%, which was higher than 47.83% of the PPH group (p < 0.05).

Conclusion

The Rho kinase inhibitor fasudil can improve pulmonary and left ventricular haemodynamics in patients with PH-HFpEF. The total effective rate was higher in the RPH group. Fasudil may be a promising targeted drug for the RPH in PH-HFpEF patients. This trial is registered with ChiCTR-INR-16009511.

DNA Damage and Pulmonary Hypertension

Pulmonary hypertension (PH) is defined by a mean pulmonary arterial pressure over 25 mmHg at rest and is diagnosed by right heart catheterization. Among the different groups of PH, pulmonary arterial hypertension (PAH) is characterized by a progressive obstruction of distal pulmonary arteries, related to endothelial cell dysfunction and vascular cell proliferation, which leads to an increased pulmonary vascular resistance, right ventricular hypertrophy, and right heart failure. Although the primary trigger of PAH remains unknown, oxidative stress and inflammation have been shown to play a key role in the development and progression of vascular remodeling. These factors are known to increase DNA damage that might favor the emergence of the proliferative and apoptosis-resistant phenotype observed in PAH vascular cells. High levels of DNA damage were reported to occur in PAH lungs and remodeled arteries as well as in animal models of PH. Moreover, recent studies have demonstrated that impaired DNA-response mechanisms may lead to an increased mutagen sensitivity in PAH patients. Finally, PAH was linked with decreased breast cancer 1 protein (BRCA1) and DNA topoisomerase 2-binding protein 1 (TopBP1) expression, both involved in maintaining genome integrity. This review aims to provide an overview of recent evidence of DNA damage and DNA repair deficiency and their implication in PAH pathogenesis.

GI ischemia in patients with portal vein thrombosis: a prospective cohort study

BACKGROUND AND AIMS

GI ischemia is a concerning adverse event of portal vein thrombosis (PVT). Minimally invasive techniques, such as visible light spectroscopy (VLS), have greatly improved the ability to diagnose GI ischemia. The aim of this study was to assess the clinical presentation and characteristics of GI ischemia in patients with PVT.

METHODS

Patients with noncirrhotic, nonmalignant PVT were included in this prospective cohort study. Clinical symptoms of GI ischemia were assessed by a structured questionnaire, VLS, and radiologic evaluation of the mesenteric vasculature. VLS measurements were compared with those in patients with cirrhosis and with a reference population.

RESULTS

We included 15 patients with chronic PVT and 1 patient with acute PVT (median age 46.1 years [interquartile range [IQR], 30.9-53.7]; 44% male). Decreased mucosal oxygenation in at least 1 location of the GI tract was found in 12 patients (75%). Compared with the reference population (median 60.0 [IQR, 56.2-61.7]), VLS measurements were mostly decreased in the descending duodenum in patients with PVT (median 55.5 [IQR, 52.3-58.8]; P = .02) and patients with cirrhosis (median 52.0 [IQR, 46.5-54.0], P = .003). Symptoms typical for GI ischemia, such as postprandial pain and exercise-induced pain, were reported in 10 patients (63%) with PVT. In patients with extension of thrombosis into the superior mesenteric vein and splenic vein and/or presence of hypercoagulability, decreased VLS measurements were observed compared with historical control subjects.

CONCLUSIONS

In patients with chronic PVT, GI ischemia is frequent. VLS enables objective and quantitative determination of GI mucosal ischemia. Onset of abdominal symptoms such as postprandial pain should prompt the physician to re-evaluate extent, cause, and treatment of PVT.

Thioredoxin 1 protects astrocytes from oxidative stress by maintaining peroxiredoxin activity

Previous studies have demonstrated that thioredoxin 1 (Trx1) exerts neuroprotective effects against cerebral ischemia/reperfusion injury caused by oxidative stress. While Trx1 is known to maintain the anti-oxidant activity of 2-Cys peroxiredoxins (Prdxs), the underlying mechanisms of its protective effects have remained to be elucidated, which was the aim of the present study. For this, an in vitro ischemic model of hypoxemia lasting for 4 h, followed by 24 h of reperfusion was used. Primary astrocytes from neonatal rats were pre-treated with small interfering RNA targeting Trx1 prior to oxygen glucose deprivation/reperfusion (OGD/R). MTS and lactate dehydrogenase assays were performed to evaluate cell viability. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot analysis were employed to assess the mRNA and protein expression levels of Prdx1-4 and Prdx-SO₃. Furthermore, a dual luciferase reporter assay was used to assess the interaction between activator protein-1 (AP-1) and Trx1. The present study demonstrated that OGD/R decreased the cell viability and increased cellular damage, which was more marked following Trx1 knockdown. The expression of Prdx1-4 and Prdx-SO₃ protein was higher in the cells subjected to OGD/R. Knockdown of Trx1 markedly decreased the levels of Prdx1-4 but increased Prdx-SO₃ mRNA and protein levels. The results of the present study also suggested that AP-1 directly activated the expression of Trx1. The present study demonstrated that Trx1 exerts its neuroprotective effects by preventing oxidative stress in astrocytes via maintaining Prdx expression.