Genetics of Pulmonary Arterial Hypertension

Biallelic variants in the calpain regulatory subunit CAPNS1 cause pulmonary arterial hypertension

Purpose

The aim of this study was to identify the monogenic cause of pulmonary arterial hypertension (PAH), a multifactorial and often fatal disease, in 2 unrelated consanguine families.

Methods

We performed exome sequencing and validated variant pathogenicity by whole-blood RNA and protein expression analysis in both families. Further RNA sequencing of preserved lung tissue was performed to investigate the consequences on selected genes that are involved in angiogenesis, proliferation, and apoptosis.

Results

We identified 2 rare biallelic variants in CAPNS1, encoding the regulatory subunit of calpain. The variants cosegregated with PAH in the families. Both variants lead to loss of function (LoF), which is demonstrated by aberrant splicing resulting in the complete absence of the CAPNS1 protein in affected patients. No other LoF CAPNS1 variant was identified in the genome data of more than 1000 patients with unresolved PAH.

Conclusion

The calpain holoenzyme was previously linked to pulmonary vascular development and progression of PAH in patients. We demonstrated that biallelic LoF variants in CAPNS1 can cause idiopathic PAH by the complete absence of CAPNS1 protein. Screening of this gene in patients who are affected by PAH, especially with suspected autosomal recessive inheritance, should be considered.

Protective effect of Alpinetin on rats with chronic obstructive pulmonary disease

To investigate the function and mechanism of Alpinetin on chronic obstructive pulmonary disease (COPD) in rat model. The markers of lung injury (body weight/pulmonary function) were measured, and the protein levels of inflammatory-, apoptosis-, and fibrotic-related were determined by Western blot. HE/TUNEL/Masson staining was performed to investigate the mechanisms involved. The levels of inflammatory factors lung injury were detected by ELISA. The in vivo activities of all molecules were determined using a rat model. Alpinetin suppressed the injury of alveolus pulmonis cells occurred in vivo due to the decrease in inflammatory factors and biochemical markers by reduced the expression of TGF-β1, α-SMA, and TNF-α (p < .05), associated with the declined of Caspase-3 and Caspase-9 (p < .01). Additionally, protective affection of Alpinetin downregulated the IL-6 and upregulated the IL-10 (p < .01). Protective affection of Alpinetin inhibits the apoptosis, inflammation, and fibrosis of alveolus pulmonis cells in rat models.

Expression of serum miR-27b and miR-451 in patients with congenital heart disease associated pulmonary artery hypertension and risk factor analysis

This study investigated expression of serum miR-27b and miR-451 in patients with congenital heart disease associated pulmonary arterial hypertension (CHD-PAH), and analyzed the risk factors of CHD-PAH. A total of 114 patients with CHD admitted to the First Affiliated Hospital of the University of South China were recruited and allocated into a study group (61 patients with PAH) and a control group (53 patients without PAH). Reverse transcription-polymerase chain reaction (RT-PCR) was employed for the qualification of serum miR-27b and miR-451, and an automatic biochemical analyzer was used for the measurement of biochemical indexes in peripheral blood, and enzyme-linked immunosorbent assay (ELISA) for the detection of serum brain natriuretic peptide (BNP) and asymmetric dimethylarginine (ADMA). The patients with CHD-PAH showed higher serum miR-27b, BNP and ADMA but lower miR-451 than the controls. Serum miR-27b was positively correlated with mean pulmonary artery pressure (mPAP), BNP and ADMA, whereas serum miR-451 was negatively correlated with them. The combined detection of miR-27b and miR-451 was more valuable than a single detection in the diagnosis of CHD-PAH. Logistic regression analysis showed that ADMA, miR-27b, miR-451 and ventricular septal defect (VSD) were independent risk factors for CHD-PAH. In conclusion, miR-27b is highly expressed and miR-451 and the expression is low in patients with CHD-PAH. miR-27b and miR-451 are significantly correlated with BNP, ADMA, and the severity of the disease. The combination of miR-27b and miR-451 has high diagnostic value and can be used as a biomarker for the diagnosis and assessment of CHD-PAH. CHD-PAH is common in children with CHD, which poses a serious threat to the life and safety. At present, there are no effective methods for its early diagnosis and treatment. MicroRNAs (miRNAs, miRs) have been found to be closely related to the pathogenesis of CHD-PAH. In this study, miR-27b and miR-451 with differential expression in CHD-PAH were evaluated, and it was found that they were of great significance in the diagnosis and assessment of CHD-PAH.

Anaemia, iron homeostasis and pulmonary hypertension: a review

Anaemia is a highly prevalent condition, which negatively impacts on patients' cardiovascular performance and quality of life. Anaemia is mainly caused by disturbances of iron homeostasis. While absolute iron deficiency mostly as a consequence of chronic blood loss or insufficient dietary iron absorption results in the emergence of iron deficiency anaemia, inflammation-driven iron retention in innate immune cells and blockade of iron absorption leads to the development of anaemia of chronic disease. Both, iron deficiency and anaemia have been linked to the clinical course of pulmonary hypertension. Various mechanistic links between iron homeostasis, anaemia, and pulmonary hypertension have been described and current treatment guidelines suggest regular iron status assessment and the implementation of iron supplementation strategies in these patients. The pathophysiology, diagnostic assessment as well as current and future treatment options concerning iron deficiency with or without anaemia in individuals suffering from pulmonary hypertension are discussed within this review.