Background: HFpEF progression is driven by a systemic proinflammatory milieu, endothelial dysfunction, and oxidative stress, leading to impaired cardiomyocyte function. Beyond its mechanical actions on the extracellular matrix, Human Relaxin-2 may directly target inflammatory and redox pathways within the myocardium.
Hypothesis: We hypothesized that acute exposure to Synthetic Human Relaxin-2 (shRlx-2) exerts anti-inflammatory and antioxidative effects in HFpEF myocardium by modulating the inflammasome pathway HMGB1–TLR–RAGE axis and redox balance, independent of titin-related changes.
Methods and Results: Left ventricular myocardial biopsies from male and female HFpEF patients and non-failing donors were incubated ex vivo with shRlx-2 (1 nmol/L, 30 min). Cytokine concentrations (TNF-α, IL-6, HMGB1), pattern recognition receptor expression (TLR2, TLR4, RAGE), and inflammasome activation (NLRP3) were quantified by ELISA. Oxidative stress was assessed via hydrogen peroxide production and GSSG/GSH ratio. In untreated HFpEF myocardium, TNF-α and IL-6 were elevated 3.5- and 2.8-fold, respectively, vs. donor (non-failing human) hearts (p < 0.001). ShRlx-2 reduced TNF-α by 45% and IL-6 by 40% (both p < 0.01), while HMGB1 decreased by nearly 50% (p < 0.001). Expression of TLR4 and RAGE was suppressed by 35% and 30%, respectively, and NLRP3 activation was attenuated (–40%, p < 0.05). Relaxin also reduced myocardial hydrogen peroxide levels by ~60% and restored redox homeostasis, as evidenced by normalization of the GSSG/GSH ratio.
Conclusion: ShRlx-2 rapidly reverses proinflammatory and oxidative stress signatures in HFpEF myocardium, acting via inhibition of the HMGB1–TLR–RAGE axis and restoration of redox balance. These findings reveal that shRlx-2 is cardioprotective and suggest its therapeutic potential as a dual modulator of both mechanical and inflammatory components of HFpEF.
