Integrative understanding of hypoxic pulmonary vasoconstriction using in vitro models: from ventilated/perfused lung to single arterial myocyte

Computational lung modelling in respiratory medicine

Computational modelling of the lungs is an active field of study that integrates computational advances with lung biophysics, biomechanics, physiology and medical imaging to promote individualized diagnosis, prognosis and therapy evaluation in lung diseases. The complex and hierarchical architecture of the lung offers a rich, but also challenging, research area demanding a cross-scale understanding of lung mechanics and advanced computational tools to effectively model lung biomechanics in both health and disease. Various approaches have been proposed to study different aspects of respiration, ranging from compartmental to discrete micromechanical and continuum representations of the lungs. This article reviews several developments in computational lung modelling and how they are integrated with preclinical and clinical data. We begin with a description of lung anatomy and how different tissue components across multiple length scales affect lung mechanics at the organ level. We then review common physiological and imaging data acquisition methods used to inform modelling efforts. Building on these reviews, we next present a selection of model-based paradigms that integrate data acquisitions with modelling to understand, simulate and predict lung dynamics in health and disease. Finally, we highlight possible future directions where computational modelling can improve our understanding of the structure-function relationship in the lung.

Pretreatment with the active fraction of Rhodiola tangutica (Maxim.) S.H. Fu rescues hypoxia-induced potassium channel inhibition in rat pulmonary artery smooth muscle cells

ETHNOPHARMACOLOGICAL RELEVANCE

Previous studies have shown that the active fraction of Rhodiola tangutica (Maxim.) S.H. Fu (ACRT) dilates pulmonary arteries and thwarts pulmonary artery remodelling. The dilatation effect of ACRT on pulmonary artery vascular rings could be reduced by potassium (K⁺) channel blockers. However the exact mechanisms of ACRT on ion channels are still unclear.

AIM OF THE STUDY

This study aimed to investigate whether the effect of ACRT on K⁺ channels inhibits cell proliferation after pulmonary artery smooth muscle cells (PASMCs) are exposed to hypoxia.

MATERIALS AND METHODS

The whole-cell patch-clamp method was used to clarify the effect of ACRT on the K⁺ current (I_K) of rat PASMCs exposed to hypoxia. The mRNA and protein expression levels were detected using real-time quantitative polymerase chain reaction (RT-qPCR) and western blotting, respectively. The intracellular calcium (Ca²⁺) concentration ([Ca²⁺]_i) values in rat PASMCs were detected by laser scanning confocal microscopy. The cell cycle and cell proliferation were assessed using flow cytometry analysis and CCK-8 and EdU assays.

RESULTS

ACRT pretreatment alleviated the inhibition of I_K induced by hypoxia in rat PASMCs. Compared with hypoxia, ACRT upregulated voltage-dependent K⁺ channel (K_v) 1.5 and big-conductance calcium-activated K⁺ channel (BK_Ca) mRNA and protein expression and downregulated voltage-dependent Ca²⁺ channel (Ca_v) 1.2 mRNA and protein expression. ACRT decreased [Ca²⁺]_i, inhibited the promotion of cyclin D1 and proliferating cell nuclear antigen (PCNA) expression, and prevented the proliferation of rat PASMCs exposed to hypoxia.

CONCLUSION

In conclusion, the present study demonstrated that ACRT plays a key role in restoring ion channel function and then inhibiting the proliferation of PASMCs under hypoxia, ACRT has preventive and therapeutic potential in hypoxic pulmonary hypertension.