Concomitant cardiac and renal dysfunction represent a clinically relevant condition with limited therapeutic options. This study examined the effects of the linear ANP fragment proANP31-67 in a preclinical model combining unilateral nephrectomy (UNX) and cardiac ischemia/reperfusion (I/R) injury. Wistar rats underwent UNX followed by I/R and were randomized to receive proANP31-67 or vehicle for 4 wk. Cardiac structure and function were evaluated by echocardiography and isolated cardiomyocyte analyses. Fourier-transform infrared (FTIR) spectroscopy was used to assess biochemical composition in cardiac and renal tissue, as well as urine. Chronic UNX induced diastolic impairment with preserved systolic function, which was further aggravated by I/R. ProANP31-67 prevented systolic deterioration, reduced myocardial fibrosis, attenuated cardiomyocyte hypertrophy, and improved Ca2+ handling, independent of blood pressure. FTIR imaging identified distinct cardiac (amino acid-, collagen-, and carbohydrate-associated) and renal (free amino acid-, protein-, and lipid-associated) spectral features across experimental groups. Conventional renal indices, including albumin-to-creatinine ratio and 24 h protein excretion, remained unchanged; however, vibrational spectroscopy detected subtle biochemical alterations in renal tissue and urine that were modulated by proANP31-67. In this model of reduced nephron mass with superimposed cardiac injury, proANP31-67 exerted marked cardioprotective effects and was associated with coordinated changes in tissue biochemical signatures, supporting further investigation of its therapeutic potential.NEW & NOTEWORTHY In a model of reduced nephron mass combined with cardiac ischemia/reperfusion injury, proANP31-67 prevented adverse cardiac remodeling independent of blood pressure. Vibrational spectroscopy identified coordinated biochemical alterations in cardiac and renal tissues not detected by conventional assays, providing molecular-level insight into cardiorenal remodeling.
Keywords: FTIR spectroscopy; biomarkers; cardiorenal syndrome; drug development; peptide-based intervention.