Anticoagulation in Pulmonary Arterial Hypertension: Do We Know the Answer?

Platelet hyperresponsiveness and increased platelet-neutrophil aggregates in dogs with myxomatous mitral valve disease and pulmonary hypertension

BACKGROUND

Pulmonary hypertension (PH) in dogs with myxomatous mitral valve disease (MMVD) is caused by increased pulmonary venous pressure. Thrombosis, vascular remodeling, and vasoconstriction mediated by platelets could exacerbate PH.

HYPOTHESIS

Dogs with PH will exhibit a hypercoagulable state, characterized by increased platelet activation, platelet-leukocyte, and platelet-neutrophil aggregate formation.

ANIMALS

Eleven dogs (≥3.5 kg) diagnosed with MMVD and PH and 10 dogs with MMVD lacking PH.

METHODS

Prospective cohort ex vivo study. All dogs underwent echocardiographic examination, CBC, 3-view thoracic radiographs, and heartworm antigen testing. Severity of PH and MMVD were assessed by echocardiography. Viscoelastic monitoring of coagulation was assessed using thromboelastography (TEG). Platelet activation and platelet-leukocyte/platelet-neutrophil interactions were assessed using flow cytometry. Plasma serotonin concentrations were measured by ELISA.

RESULTS

Unstimulated platelets from dogs with MMVD and PH expressed more surface P-selectin than MMVD controls (P = .03). Platelets from dogs with MMVD and PH had persistent activation in response to agonists. The number of platelet-leukocyte aggregates was higher in dogs with MMVD and PH compared with MMVD controls (P = .01). Ex vivo stimulation of whole blood resulted in higher numbers of platelet-neutrophil aggregates in dogs with MMVD and PH (P = .01). Assessment of hypercoagulability based on TEG or plasma serotonin concentrations did not differ between groups.

CONCLUSION AND CLINICAL IMPORTANCE

Platelet hyperresponsiveness and increased platelet-neutrophil interaction occur in dogs with MMVD and PH, suggesting that platelets play a role of in the pathogenesis of PH. Clinical benefits of antiplatelet drugs in dogs with MMVD and PH require further investigation.

A peripheral system disease-Pulmonary hypertension

Pulmonary hypertension (PH) is a cardiovascular disorder characterized by substantial morbidity and mortality rates. It is a chronic condition characterized by intricate pathogenesis and uncontrollable factors. We summarized the pathological effects of estrogen, genetics, neuroinflammation, intestinal microbiota, metabolic reorganization, and histone modification on PH. PH is not only a pulmonary vascular disease, but also a systemic disease. The findings emphasize that the onset of PH is not exclusively confined to the pulmonary vasculature, consequently necessitating treatment approaches that extend beyond targeting pulmonary blood vessels. Hence, the research on the pathological mechanism of PH is not limited to target organs such as pulmonary vessels, but also focuses on exploring other fields (such as estrogen, genetics, neuroinflammation, intestinal microbiota, metabolic reorganization, and histone modification).

Natural Products for the Treatment of Pulmonary Hypertension: Mechanism, Progress, and Future Opportunities

Pulmonary hypertension (PH) is a lethal disease due to the remodeling of pulmonary vessels. Its pathophysiological characteristics include increased pulmonary arterial pressure and pulmonary vascular resistance, leading to right heart failure and death. The pathological mechanism of PH is complex and includes inflammation, oxidative stress, vasoconstriction/diastolic imbalance, genetic factors, and ion channel abnormalities. Currently, many clinical drugs for the treatment of PH mainly play their role by relaxing pulmonary arteries, and the treatment effect is limited. Recent studies have shown that various natural products have unique therapeutic advantages for PH with complex pathological mechanisms owing to their multitarget characteristics and low toxicity. This review summarizes the main natural products and their pharmacological mechanisms in PH treatment to provide a useful reference for future research and development of new anti-PH drugs and their mechanisms.

Urokinase-loaded cyclic RGD-decorated liposome targeted therapy for in-situ thrombus of pulmonary arteriole of pulmonary hypertension

Backgroud:In-situ thrombosis is a significant pathophysiological basis for the development of pulmonary hypertension (PH). However, thrombolytic therapy for in-situ thrombus in PH was often hampered by the apparent side effects and the low bioavailability of common thrombolytic medications. Nanoscale cyclic RGD (cRGD)-decorated liposomes have received much attention thanks to their thrombus-targeting and biodegradability properties. As a result, we synthesized urokinase-loaded cRGD-decorated liposome (UK-cRGD-Liposome) for therapy of in-situ thrombosis as an exploration of pulmonary hypertensive novel therapeutic approaches.

Purpose: To evaluate the utilize of UK-cRGD-Liposome for targeted thrombolysis of in-situ thrombus in PH and to explore the potential mechanisms of in-situ thrombus involved in the development of PH.

Methods: UK-cRGD-Liposome nanoscale drug delivery system was prepared using combined methods of thin-film hydration and sonication. Induced PH via subcutaneous injection of monocrotaline (MCT). Fibrin staining (modified MSB method) was applied to detect the number of vessels within-situ thrombi in PH. Echocardiography, hematoxylin-eosin (H & E) staining, and Masson’s trichrome staining were used to analyze right ventricular (RV) function, pulmonary vascular remodeling, as well as RV remodeling.

Results: The number of vessels with in-situ thrombi revealed that UK-cRGD-Liposome could actively target urokinase to in-situ thrombi and release its payload in a controlled manner in the in vivo environment, thereby enhancing the thrombolytic effect of urokinase. Pulmonary artery hemodynamics and echocardiography indicated a dramatical decrease in pulmonary artery pressure and a significant improvement in RV function post targeted thrombolytic therapy. Moreover, pulmonary vascular remodeling and RV remodeling were significantly restricted post targeted thrombolytic therapy.

Conclusion: UK-cRGD-Liposome can restrict the progression of PH and improve RV function by targeting the dissolution of pulmonary hypertensive in-situ thrombi, which may provide promising therapeutic approaches for PH.

Pulmonary Hypertension in Scleroderma- Evaluation and Management

Pulmonary Arterial Hypertension (PAH) is a clinical syndrome consisting of physiologic/hemodynamic criteria that are a consequence of several etiologies. Systemic Sclerosis (SSc), one of the most common causes of PAH, is an autoimmune disorder of the connective tissue leading to fibrosis that involves the skin, gastrointestinal tract, lungs, heart, kidney etc. SSc has an annual prevalence of one to five cases for every 1000 individuals and nearly 15 percent of all cases develop PAH. At its core, Pulmonary hypertension (PH) in SSc is an obliterative vasculopathy in small to medium-sized pulmonary arterioles. A host of other local and systemic mechanisms operate in concert to gradually alter the hemodynamics resulting in elevated pulmonary vascular resistance and thus right ventricular afterload. A diagnosis of PAH in SSc is virtually a death sentence, with studies reporting a mortality rate of 50 per cent in the 3 years of diagnosis. Therefore, developing and implementing a robust screening and diagnosis protocol is crucial in the fight against this pervasive disease. This review aims to summarize the current literature of PAH in SSc, with a special focus on the screening and diagnosis protocols, newer treatment options and prognostic indicators for the same.

Effects of oral anticoagulant therapy in patients with pulmonary diseases

Background

To evaluate the effect of oral anticoagulants (OACs) therapy, including vitamin K antagonist (VKA) and direct oral anticoagulants (DOAC) in patients with pulmonary diseases.

Methods

Literature from PubMed, MEDLINE, and Cochrane Library were screened until June 2022. Studies assessing OACs for pulmonary hypertension (PH), pulmonary embolism (PE), pulmonary fibrosis (PF), or chronic obstructive pulmonary disease (COPD) were evaluated for inclusion.

Results

Our study indicated that in patients with PH, PE, and COPD, OACs could significantly reduce the mortality risk, and the effects of VKA and DOACs without statistical difference in reducing the risk of recurrent embolism events. In patients with sclerosis-associated pulmonary arterial hypertension (SSc-PAH) or idiopathic pulmonary fibrosis (IPF), vitamin K antagonist (warfarin) significantly increased the mortality risk, while DOACs were not. As for the safety outcome of OACs, existing studies indicate that compared with patients treated with warfarin, the users of DOAC have a lower risk of major bleeding, while there is no statistical significance between them in non-major bleeding events. In current guidelines, the anticoagulation regimen for patients with pulmonary disease has not been defined. The results of our study confirm that DOACs (apixaban, rivaroxaban, dabigatran, and edoxaban) are superior to VKAs in the efficacy and safety outcomes of patients with pulmonary disease.

Conclusions

Oral anticoagulant therapy brings benefits to patients with PH, PE, or COPD, while the anticoagulation regimen for patients with SSc-PAH or IPF requires serious consideration. Compared with VKA, DOAC is a non-inferior option for anticoagulation in pulmonary disease treatment. Further studies are still needed to provide more reliable evidence about the safety outcome of pulmonary disease anticoagulation.

Mechanistic and therapeutic perspectives of baicalin and baicalein on pulmonary hypertension: A comprehensive review

Pulmonary hypertension (PH) is a chronic and fatal disease, for which new therapeutic drugs and approaches are needed urgently. Baicalein and baicalin, the active compounds of the traditional Chinese medicine, Scutellaria baicalensis Georgi, exhibit a wide range of pharmacological activities. Numerous studies involving in vitro and in vivo models of PH have revealed that the treatment with baicalin and baicalein may be effective. This review summarizes the potential mechanisms driving the beneficial effects of baicalin and baicalein treatment on PH, including anti-inflammatory response, inhibition of pulmonary smooth muscle cell proliferation and endothelial-to-mesenchymal transformation, stabilization of the extracellular matrix, and mitigation of oxidative stress. The pharmacokinetics of these compounds have also been reviewed. The therapeutic potential of baicalin and baicalein warrants their continued study as natural treatments for PH.

2020 Chinese Expert-based Consensus on the Diagnosis and Treatment of Connective Tissue Disease Associated Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a severe complication of connective tissue disease (CTD) and is one of the leading causes of morbidity and mortality among patients with this condition. To establish an expert-based consensus on the diagnosis and treatment of CTD-associated PAH, a multidisciplinary consensus development panel was established. The consensus panel is composed of 45 experts in rheumatology, cardiology, pulmonology, and radiology, most of whom are members of the Group of Pulmonary Vascular and Interstitial Lung Diseases (ILD) Associated with Rheumatic Diseases. The consensus development panel compiled 9 recommendations for the diagnosis and treatment of CTD-associated PAH. It covers screening, diagnosis, disease evaluation, risk assessment, the use of immunosuppressive agents, and PAH-specific therapy with a treat-to-target approach. The consensus is intended to facilitate decision-making and standardize the care of CTD-associated PAH in China.