Gradual reduction of afterload burden via pulmonary artery band absorption in mice fully reversed established right ventricular dysfunction, with hypertrophic normalization preceding fibrotic reversal.
Does gradual reduction of afterload burden (de-PAB) improve right ventricular function and reverse remodeling in mice with pulmonary hypertension-associated RV dysfunction?
Functional right ventricular recovery after pressure overload relief is linked to hypertrophic normalization that precedes fibrotic and vascular reverse-remodeling in a novel mouse model.
AIMS: The temporal sequence of events underlying functional right ventricular (RV) recovery after improvement of pulmonary hypertension-associated pressure overload is unknown. We sought to establish a novel mouse model of gradual RV recovery from pressure overload and use it to delineate RV reverse-remodelling events. METHODS AND RESULTS: Surgical pulmonary artery banding (PAB) around a 26-G needle induced RV dysfunction with increased RV pressures, reduced exercise capacity and caused liver congestion, hypertrophic, fibrotic, and vascular myocardial remodelling within 5 weeks of chronic RV pressure overload in mice. Gradual reduction of the afterload burden through PA band absorption (de-PAB)-after RV dysfunction and structural remodelling were established-initiated recovery of RV function (cardiac output and exercise capacity) along with rapid normalization in RV hypertrophy (RV/left ventricular + S and cardiomyocyte area) and RV pressures (right ventricular systolic pressure). RV fibrotic (collagen, elastic fibres, and vimentin+ fibroblasts) and vascular (capillary density) remodelling were equally reversible; however, reversal occurred at a later timepoint after de-PAB, when RV function was already completely restored. Microarray gene expression (ClariomS, Thermo Fisher Scientific, Waltham, MA, USA) along with gene ontology analyses in RV tissues revealed growth factors, immune modulators, and apoptosis mediators as major cellular components underlying functional RV recovery. CONCLUSION: We established a novel gradual de-PAB mouse model and used it to demonstrate that established pulmonary hypertension-associated RV dysfunction is fully reversible. Mechanistically, we link functional RV improvement to hypertrophic normalization that precedes fibrotic and vascular reverse-remodelling events.
Boehm et al. (Fri,) conducted a other in Pulmonary hypertension-associated right ventricular dysfunction. Gradual reduction of afterload burden through PA band absorption (de-PAB) vs. Chronic RV pressure overload (PAB) was evaluated on Functional right ventricular recovery and reverse-remodelling events. Gradual reduction of afterload burden via pulmonary artery band absorption in mice fully reversed established right ventricular dysfunction, with hypertrophic normalization preceding fibrotic reversal.