Urinary proteomic signature of mineralocorticoid receptor antagonism by spironolactone: evidence from the HOMAGE trial.

OBJECTIVE: Heart failure (HF) is characterised by collagen deposition. Urinary proteomic profiling (UPP) followed by peptide sequencing identifies parental proteins, for over 70% derived from collagens. This study aimed to refine understanding of the antifibrotic action of spironolactone. METHODS: In this substudy (n=290) to the Heart 'Omics' in Ageing Study trial, patients were randomised to usual therapy combined or not with spironolactone 25-50 mg/day and followed for 9 months. The analysis included 1498 sequenced urinary peptides detectable in ≥30% of patients and carboxyterminal propeptide of procollagen I (PICP) and PICP/carboxyterminal telopeptide of collagen I (CITP) as serum biomarkers of COL1A1 synthesis. After rank normalisation of biomarker distributions, between-group differences in their changes were assessed by multivariable-adjusted mixed model analysis of variance. Correlations between the changes in urinary peptides and in serum PICP and PICP/CITP were compared between groups using Fisher's Z transform. RESULTS: Multivariable-adjusted between-group differences in the urinary peptides with error 1 rate correction were limited to 27 collagen fragments, of which 16 were upregulated (7 COL1A1 fragments) on spironolactone and 11 downregulated (4 COL1A1 fragments). Over 9 months of follow-up, spironolactone decreased serum PICP from 81 (IQR 66-95) to 75 (61-90) µg/L and PICP/CITP from 22 (17-28) to 18 (13-26), whereas no changes occurred in the control group, resulting in a difference (spironolactone minus control) expressed in standardised units of -0.321 (95% CI 0.0007). Spironolactone did not affect the correlations between changes in urinary COL1A1 fragments and in PICP or the PICP/CITP ratio. CONCLUSIONS: Spironolactone decreased serum markers of collagen synthesis and predominantly downregulated urinary collagen-derived peptides, but upregulated others. The interpretation of these opposite UPP trends might be due to shrinking the body-wide pool of collagens, explaining downregulation, while some degree of collagen synthesis must be maintained to sustain vital organ functions, explaining upregulation. Combining urinary and serum fibrosis markers opens new avenues for the understanding of the action of antifibrotic drugs. TRIAL REGISTRATION NUMBER: NCT02556450.

Dyskalemia in people at increased risk for heart failure: findings from the heart 'OMics' in AGEing (HOMAGE) trial.

AIMS: In people at risk of heart failure (HF) enrolled in the Heart 'OMics' in AGEing (HOMAGE) trial, spironolactone reduced circulating markers of collagen synthesis, natriuretic peptides, and blood pressure and improved cardiac structure and function. In the present report, we explored factors associated with dyskalaemia. METHODS AND RESULTS: The HOMAGE trial was an open-label study comparing spironolactone (up to 50 mg/day) versus standard care in people at risk for HF. After randomization, serum potassium was assessed at 1 and 9 months and was defined as low when ≤3.5 mmol/L (hypokalaemia) and high when ≥5.5 mmol/L (hyperkalaemia). Multivariable logistic regression models were constructed to identify clinical predictors of dyskalaemia. A total of 513 participants (median age 74 years, 75% men, median estimated glomerular filtration rate 71 mL/min/1.73 m2 ) had serum potassium available and were included in this analysis. At randomization, 88 had potassium < 4.0 mmol/L, 367 had potassium 4.0-5.0 mmol/L, and 58 had potassium > 5.0 mmol/L. During follow-up, on at least one occasion, a serum potassium < 3.5 mmol/L was observed in 6 (1.2%) and <4.0 mmol/L in 46 (9%) participants, while a potassium > 5.0 mmol/L was observed in 38 (8%) and >5.5 mmol/L in 5 (1.0%) participants. The median (percentile25-75 ) increase in serum potassium with spironolactone during the study was 0.23 (0.16; 0.29) mmol/L. Because of the low incidence of dyskalaemia, for regression analysis, hypokalaemia and hyperkalaemia thresholds were set at <4.0 and >5.0 mmol/L, respectively. The occurrence of a serum potassium > 5.0 mmol/L during follow-up was positively associated with the presence of diabetes mellitus {odds ratio [OR]: 1.21 [95% confidence interval (CI) 2.14; 3.79]} and randomization to spironolactone (OR: 2.83 [95% CI 1.49; 5.37]). Conversely, the occurrence of a potassium concentration < 4.0 mmol/L was positively associated with the use of thiazides (OR: 2.39 [95% CI 1.32; 4.34]), blood urea concentration (OR: 2.15 [95% CI 1.34; 3.39] per 10 mg/dL), and history of hypertension (OR: 2.32 [95% CI 1.02; 5.29]) and negatively associated with randomization to spironolactone (OR: 0.30 [95% CI 0.18; 0.52]). CONCLUSIONS: In people at risk for developing HF and with relatively normal renal function, spironolactone reduced the risk of hypokalaemia and, at the doses used, was not associated with the occurrence of clinically meaningful hyperkalaemia.

Effects of spironolactone on serum markers of fibrosis in people at high risk of developing heart failure: rationale, design and baseline characteristics of a proof-of-concept, randomised, precision-medicine, prevention trial. The Heart OMics in AGing (HOMAGE) trial.

AIMS: Asymptomatic patients with coronary artery disease (CAD), hypertension and/or type 2 diabetes mellitus (T2DM) are at greater risk of developing heart failure (HF). Fibrosis, leading to myocardial and vascular dysfunction, might be an important pathway of progression. The Heart OMics in AGing (HOMAGE) trial aims to investigate the effects of spironolactone on serum markers of collagen metabolism and on cardiovascular structure and function in people at risk of developing HF and potential interactions with a marker of fibrogenic activity, galectin-3. METHODS AND RESULTS: The HOMAGE trial is a prospective, randomised, open-label, blinded endpoint (PROBE) study comparing spironolactone (up to 50 mg/day) and standard care over 9 months in people with clinical risk factors for developing HF, including hypertension, CAD and T2DM, and elevated plasma concentrations of N-terminal pro-B-type natriuretic peptide (NT-proBNP, 125 to 1000 ng/L) or B-type natriuretic peptide (BNP, 35 to 280 ng/L). Exclusion criteria included left ventricular ejection fraction < 45%, atrial fibrillation, severe renal dysfunction, or treatment with loop diuretics. The primary endpoint was the interaction between change in serum concentrations of procollagen type III N-terminal propeptide (PIIINP) and treatment with spironolactone according to median plasma concentrations of galectin-3 at baseline. For the 527 participants enrolled, median (interquartile range) age was 73 (69-79) years, 135 (26%) were women, 412 (78%) had hypertension, 377 (72%) CAD, and 212 (40%) T2DM. At baseline, medians (interquartile ranges) were for left ventricular ejection fraction 63 (58-67) %, for left atrial volume index 31 (26-37) mL/m2 , for plasma NT-proBNP 214 (137-356) ng/L, for serum PIIINP 3.9 (3.1-5.0) ng/mL, and for galectin-3 16.1 (13.5-19.7) ng/mL. CONCLUSIONS: The HOMAGE trial will provide insights on the effect of spironolactone on pathways that might drive progression to HF. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov NCT02556450.