Plasma Biomarker Profiling in Heart Failure Patients with Preserved Ejection Fraction before and after Spironolactone Treatment: Results from the Aldo-DHF Trial

The pathophysiology of heart failure with preserved ejection fraction (HFpEF) is poorly understood and therapeutic strategies are lacking. This study aimed to identify plasma proteins with pathophysiological relevance in HFpEF and with respect to spironolactone-induced effects. We assessed 92 biomarkers in plasma samples from 386 HFpEF patients—belonging to the Aldo-DHF trial—before (baseline, BL) and after one-year treatment (follow up, FU) with spironolactone (verum) or a placebo. At BL, various biomarkers showed significant associations with the two Aldo-DHF primary end point parameters: 33 with E/e’ and 20 with peak VO2. Ten proteins including adrenomedullin, FGF23 and inflammatory peptides (e.g., TNFRSF11A, TRAILR2) were significantly associated with both parameters, suggesting a role in the clinical HFpEF presentation. For 13 proteins, expression changes from BL to FU were significantly different between verum and placebo. Among them were renin, growth hormone, adrenomedullin and inflammatory proteins (e.g., TNFRSF11A, IL18 and IL4RA), indicating distinct spironolactone-mediated effects. BL levels of five proteins, e.g., inflammatory markers such as CCL17, IL4RA and IL1ra, showed significantly different effects on the instantaneous risk for hospitalization between verum and placebo. This study identified plasma proteins with different implications in HFpEF and following spironolactone treatment. Future studies need to define their precise mechanistic involvement

Distinct regulatory effects of myeloid cell and endothelial cell Nox2 on blood pressure

Background -Hypertension due to increased renin angiotensin system (RAS) activation is associated with elevated reactive oxygen species (ROS) production. Previous studies implicate NADPH oxidase (Nox) proteins as important ROS sources during RAS activation, with different Nox isoforms being potentially involved. Among these, Nox2 is expressed in multiple cell types including endothelial cells, fibroblasts, immune cells and microglia. Blood pressure (BP) is regulated at central nervous system, renal and vascular levels but the cell-specific role of Nox2 in BP regulation is unknown. Methods -We generated a novel mouse model with a Floxed Nox2 gene and used Tie2-Cre, LysM Cre or Cdh5-CreERT2 driver lines to develop cell-specific models of Nox2 perturbation to investigate its role in BP regulation. Results -Unexpectedly, Nox2 deletion in myeloid but not endothelial cells resulted in a significant reduction in basal BP. Tie2-CreNox2 knockout (KO) mice (in which Nox2 was deficient in both endothelial cells and myeloid cells) and LysM Cre Nox2KO mice (in which Nox2 was deficient in myeloid cells) both had significantly lower BP than littermate controls whereas basal BP was unaltered in Cdh5-CreERT2 Nox2 KO mice (in which Nox2 is deficient only in endothelial cells). The lower BP was attributable to an increased NO bioavailability which dynamically dilated resistance vessels in vivo under basal conditions, without change in renal function. Myeloid-specific Nox2 deletion had no effect on angiotensin II-induced hypertension which, however, was blunted in Tie2-CreNox2KO mice along with preservation of endothelium-dependent relaxation during angiotensin II stimulation. Conclusions -We identify a hitherto unrecognized modulation of basal BP by myeloid cell Nox2 whereas endothelial cell Nox2 regulates angiotensin II-induced hypertension. These results identify distinct cell-specific roles for Nox2 in BP regulation

Echocardiographic evaluation of diastolic function in mouse models of heart disease

Background Mouse models of heart disease are extensively employed. The echocardiographic characterization of contractile function is usually focused on systolic function with fewer studies assessing diastolic function. Furthermore, the applicability of diverse echocardiographic parameters of diastolic function that are commonly used in humans has not been extensively evaluated in different pathophysiological models in mice. Methods and results We used high resolution echocardiography to evaluate parameters of diastolic function in mouse models of chronic pressure overload (aortic constriction), volume overload (aorto-caval shunt), heart failure with preserved ejection fraction (HFpEF; DOCA-salt hypertension), and acute sarcoplasmic reticulum dysfunction induced by thapsigargin - all known to exhibit diastolic dysfunction. Left atrial area increased in all three chronic models while mitral E/A was difficult to quantify at high heart rates. Isovolumic relaxation time (IVRT) and Doppler E/E′ increased significantly and the peak longitudinal strain rate during early filling (peak reverse longitudinal strain rate) decreased significantly after aortic constriction, with the changes being proportional to the magnitude of hypertrophy. In the HFpEF model, reverse longitudinal strain rate decreased significantly but changes in IVRT and E/E′ were non-significant, consistent with less severe dysfunction. With volume overload, there was a significant increase in reverse longitudinal strain rate and decrease in IVRT, indicating a restrictive physiology. Acute thapsigargin treatment caused significant prolongation of IVRT and decrease in reverse longitudinal strain rate. Conclusion These results indicate that the combined measurement of left atrial area plus reverse longitudinal strain rate and/or IVRT provide an excellent overall assessment of diastolic function in the diseased mouse heart, allowing distinction between different types of pathophysiology

Plasma Biomarker Profiling in Heart Failure Patients with Preserved Ejection Fraction before and after Spironolactone Treatment: Results from the Aldo-DHF Trial

The pathophysiology of heart failure with preserved ejection fraction (HFpEF) is poorly understood and therapeutic strategies are lacking. This study aimed to identify plasma proteins with pathophysiological relevance in HFpEF and with respect to spironolactone-induced effects. We assessed 92 biomarkers in plasma samples from 386 HFpEF patients—belonging to the Aldo-DHF trial—before (baseline, BL) and after one-year treatment (follow up, FU) with spironolactone (verum) or a placebo. At BL, various biomarkers showed significant associations with the two Aldo-DHF primary end point parameters: 33 with E/e’ and 20 with peak VO2. Ten proteins including adrenomedullin, FGF23 and inflammatory peptides (e.g., TNFRSF11A, TRAILR2) were significantly associated with both parameters, suggesting a role in the clinical HFpEF presentation. For 13 proteins, expression changes from BL to FU were significantly different between verum and placebo. Among them were renin, growth hormone, adrenomedullin and inflammatory proteins (e.g., TNFRSF11A, IL18 and IL4RA), indicating distinct spironolactone-mediated effects. BL levels of five proteins, e.g., inflammatory markers such as CCL17, IL4RA and IL1ra, showed significantly different effects on the instantaneous risk for hospitalization between verum and placebo. This study identified plasma proteins with different implications in HFpEF and following spironolactone treatment. Future studies need to define their precise mechanistic involvement

Case Report: High-dose immunoglobulins prior to plasma exchange in severe pulmonary renal syndrome

Plasma exchange rapidly depletes pathogenic anti-neutrophil cytoplasmic autoantibodies (ANCAs) and is considered for induction therapy in severe ANCA-associated vasculitis. The aim of plasma exchange is to remove putative disease mediators from the circulation, such as toxic macromolecules and pathogenic ANCAs. To our knowledge, we here provide the first report of applying high-dose IVIGs prior to plasma exchange and assessment of ANCA autoantibody elimination in a patient with severe pulmonary renal syndrome due to ANCA-associated vasculitis. After high-dose application of intravenous immunoglobulins (IVIGs) prior to plasma exchange treatment, efficacy of myeloperoxidase (MPO)-ANCA autoantibody elimination was substantially increased, associated with rapid clearance of MPO-ANCA autoantibodies. High-dose IVIGs resulted in marked reduction of MPO-ANCA autoantibody levels and did not directly affect autoantibody clearance by plasma exchange itself, as also confirmed by comparable MPO-ANCAs in the exchange fluid relative to serum levels. Moreover, measurements of serum creatinine and albuminuria confirmed that high-dose IVIGs were well tolerated and did not exacerbate kidney injury.Open-Access-Publikationsfonds 202