Pulmonary hypertension and right ventricular failure in left ventricular systolic dysfunction

Antenatal Hypoxia Affects Pulmonary Artery Contractile Functions via Downregulating L-type Ca2+ Channels Subunit Alpha1 C in Adult Male Offspring

Background

Antenatal intrauterine fetal hypoxia is a common pregnancy complication that has profound adverse effects on an individual's vascular health later in life. Pulmonary arteries are sensitive to hypoxia, but adverse effects of antenatal hypoxia on pulmonary vasoreactivities in the offspring remain unknown. This study aimed to determine the effects and related mechanisms of antenatal hypoxia on pulmonary artery functions in adult male offspring.

Methods and Results

Pregnant Sprague‐Dawley rats were housed in a normoxic or hypoxic (10.5% O₂) chamber from gestation days 10 to 20. Male offspring were euthanized at 16 weeks old (adult offspring). Pulmonary arteries were collected for vascular function, electrophysiology, target gene expression, and promoter methylation studies. In pulmonary artery rings, contractions to serotonin hydrochloride, angiotensin II, or phenylephrine were reduced in the antenatal hypoxic offspring, which resulted from inactivated L‐type Ca²⁺ channels. In pulmonary artery smooth muscle cells, the basal whole‐cell Ca²⁺ currents, as well as vasoconstrictor‐induced Ca²⁺ transients were significantly reduced in antenatal hypoxic offspring. In addition, increased promoter methylations within L‐type Ca²⁺ channel subunit alpha1 C were compatible with its reduced expressions.

Conclusions

This study indicated that antenatal hypoxia programmed long‐lasting vascular hypocontractility in the male offspring that is linked to decreases of L‐type Ca²⁺ channel subunit alpha1 C in the pulmonary arteries. Antenatal hypoxia resulted in pulmonary artery adverse outcomes in postnatal offspring, was strongly associated with reprogrammed L‐type Ca²⁺ channel subunit alpha1 C expression via a DNA methylation‐mediated epigenetic mechanism, advancing understanding toward the effect of antenatal hypoxia in early life on long‐term vascular health.

Narrative review of sleep and pulmonary hypertension

Pulmonary hypertension (PH) is a condition of raised pulmonary artery pressure (PAP), which may be secondary to a number of causes, one of which is sleep disordered breathing (SDB). When PH complicates SDB, it carries a significant burden of morbidity and mortality due to the risk of progression to right ventricular failure over time. This narrative review will cover the definition and classification of PH, and explore the epidemiology of PH in SDB. The mechanisms by which the two conditions are linked will be reviewed. Repetitive hypoxia with or without hypercapnia alongside frequent arousals can result in important metabolic and pulmonary vascular consequences for the left and right heart. MEDLINE was used to search for all relevant articles and abstracts published from January 1960 to October 2019 inclusive (in all languages). Current best practice in the investigation and management of PH complicating SDB will be reviewed. Important diagnostic investigations and when to consider and screen further for PH in patients with SDB will be discussed. Optimal disease management must include control of SDB with therapy. Additional treatment options will be reviewed. Areas for further research will be highlighted.

Pulmonary Hypertension in Heart Failure Patients Presenting at OAUTHC, Ile-Ife, Nigeria

Background

Pulmonary hypertension (PH) is common in heart failure patients. Literature on PH in heart failure is sparse in Nigeria. This study was carried out to determine the prevalence of PH in heart failure patients and ascertain the relationship between left ventricular systolic and diastolic function and the degree of PH.

Methods

A total of 125 heart failure patients had echocardiography done. PH was diagnosed using tricuspid regurgitation jet and pulmonary ejection jet profile.

Results

PH was present in 70.4% of heart failure patients. Estimated mean pulmonary arterial pressure increased with increasing severity of systolic and diastolic dysfunction and had significantly negative correlation with ejection fraction, fractional shortening, and early mitral annular tissue diastolic velocity ( E′), but positive correlation with left ventricular end-systolic volume, right ventricular dimension, transmitral E to A ratio, and E/E′ ratio.

Conclusion

PH is very common in heart failure and has significant relationship with left ventricular function.

A Practical Clinical Approach to the Diagnosis and Treatment of Patients with Pulmonary Hypertension

Pulmonary hypertension is defined by a mean pulmonary artery pressure of >25 mmHg at rest or 30 mmHg during exercise. There are many causes and currently diseases causing the condition are classified into five groups. The greatest elevation in pulmonary arterial pressure is found among those disorders in group 1 (known as pulmonary arterial hypertension [PAH]) and research and targeted therapy has focused on this group in particular, although patients in group 4 (chronic thromboembolic PH [CTEPH]) also receive advanced pulmonary vasodilator therapy. The symptoms of PH are often vague and the diagnosis is frequently missed or delayed. Efforts are therefore being made to improve awareness of PH among clinicians to enable prompt referral to a PH unit to confirm the diagnosis and instigate appropriate therapy. Multi-disciplinary team (MDT) discussion is necessary if patients with PH require surgical intervention or become pregnant. For patients in the other PH groups, treatment is usually concentrated on the primary disorder. A small number of patients with PAH will respond to calcium-channel-blocking agents. Specific targeted therapy is often given in combination depending on the patients functional performance status. Available agents include phosphodiesterase type V inhibitors, endothelin receptor antagonists, prostglandin analogues and nitric oxide. Many novel agents are under review. For carefully selected patients surgical options, include lung transplantation, pulmonary thromboendarterectomy and atrial septostomy.

Modulation of miRNAs in Pulmonary Hypertension

MicroRNAs (miRNAs) have emerged as a new class of posttranscriptional regulators of many cardiac and vascular diseases. They are a class of small, noncoding RNAs that contributes crucial roles typically through binding of the 3′-untranslated region of mRNA. A single miRNA may influence several signaling pathways associated with cardiac remodeling by targeting multiple genes. Pulmonary hypertension (PH) is a rare disorder characterized by progressive obliteration of pulmonary (micro) vasculature that results in elevated vascular resistance, leading to right ventricular hypertrophy (RVH) and RV failure. The pathology of PH involves vascular cell remodeling including pulmonary arterial endothelial cell (PAEC) dysfunction and pulmonary arterial smooth muscle cell (PASMC) proliferation. There is no cure for this disease. Thus, novel intervention pathways that govern PH induced RVH may result in new treatment modalities. Current therapies are limited to reverse the vascular remodeling. Recent studies have demonstrated the roles of various miRNAs in the pathogenesis of PH and pulmonary disorders. This review provides an overview of recent discoveries on the role of miRNAs in the pathogenesis of PH and discusses the potential for miRNAs as therapeutic targets and biomarkers of PH at clinical setting.

Stem cell therapy for chronic heart failure: an updated appraisal

INTRODUCTION

Significant advances have been made to understand the mechanisms involved in cardiac cell-based therapies. The early translational application of basic science knowledge has led to several animal and human clinical trials. The initial promising beneficial effect of stem cells on cardiac function restoration has been eclipsed by the inability of animal studies to translate into sustained clinical improvements in human clinical trials.

AREAS COVERED

In this review, the authors cover an updated overview of various stem cell populations used in chronic heart failure. A critical review of clinical trials conducted in advanced heart failure patients is proposed, and finally promising avenues for developments in the field of cardiac cell-based therapies are presented.

EXPERT OPINION

Several questions remain unanswered, and this limits our ability to understand basic mechanisms involved in stem cell therapeutics. Human studies have revealed critical unresolved issues. Further elucidation of the proper timing, mode delivery and prosurvival factors is imperative, if the field is to advance. The limited benefits seen to date are simply not enough if the potential for substantial recovery of nonfunctioning myocardium is to be realized.

Low birth weight and very low birth weight neonates with congenital heart disease: timing of surgery, reasons for delaying or not delaying surgery

Conventional management of low birth weight and very low birth weight neonates was composed of deferring corrective surgery by aggressive medical management or palliative surgery which does not require cardiopulmonary bypass. However, while waiting for weight gain, these neonates are at risk for various comorbidities. In the current era, this "wait and let the baby grow" approach has not been shown to result in better clinical outcomes. Early primary repair hence has become the standard strategy for congenital heart disease requiring surgery in these neonates. However, there still exist some circumstances, which are considered to be unfavorable for corrective surgery due to medical, physiologic, surgeon's technical and institutional-systemic factors. We reviewed the recent literature and examined the reasons for delaying or not delaying surgery.