Severe hyper-catecholaminergic states likely cause heart failure and cardiac fibrosis. While previous studies demonstrated the effects of beta-blockade in experimental models of single-catecholamine excess states, the detailed benefits of beta-blockade in more realistic models of hyper-adrenergic states are less clearly understood. In this study, we examined different therapeutic dosages and the effects of propranolol in rats with hyper-acute catecholamine-induced heart failure, and subsequent cardiopulmonary changes. Rats (n = 41) underwent a 6 h infusion of epinephrine and norepinephrine alone, with additional low-dose (1 mg/kg) or high-dose propranolol (10 mg/kg) at hour 1. Cardiac and pulmonary tissues were examined after 6 h. Catecholamine-only groups had the lowest survival rate. Higher doses of propranolol (15 mg/kg) caused similarly low survival rates and were not further analyzed. All low-dose propranolol rats survived, with a modest survival improvement in the high-dose propranolol groups. Left ventricular (LV) systolic pressure and LV end-diastolic pressure improved maximally with low-dose propranolol. Cardiac immunohistochemistry revealed an LV upregulation of FGF-23 in the catecholamine groups, and this improved in low-dose propranolol groups. These results suggest catecholamine-induced heart failure initiates early pre-fibrotic pathways through FGF-23 upregulation. Low-dose propranolol exerted cardio-preventative effects through FGF-23 downregulation and hemodynamic-parameter improvement in our model of hyper-acute catecholamine-induced heart failure.

Exposure to hypoxia during the early postnatal period can have adverse effects on vital organs. Neonatal Sprague–Dawley rats housed in a hypoxic chamber were compared to those in a normoxic chamber from postnatal days 0 to 7. Arterial blood was collected to evaluate renal function and hypoxia. Kidney morphology and fibrosis were evaluated using staining methods and immunoblotting. In the kidneys of the hypoxic group, protein expressions of hypoxia-inducible factor-1 were higher than those in the normoxic group. Hypoxic rats had higher levels of hematocrit, serum creatinine, and lactate than normoxic rats. Body weight was reduced, and protein loss of kidney tissue was observed in hypoxic rats compared to normoxic rats. Histologically, hypoxic rats showed glomerular atrophy and tubular injury. Renal fibrosis with collagen fiber deposition was observed in the hypoxic group. The expression of nicotinamide adenine dinucleotide phosphate oxidases was enhanced in the kidneys of hypoxic rats. Proteins involved in apoptosis were upregulated in the kidneys of hypoxic rats. An increase in the expression of pro-inflammatory cytokines was also observed in the kidneys of hypoxic rats. Hypoxic kidney injury in neonatal rats was associated with oxidative stress, inflammation, apoptosis, and fibrosis.

Excessive administration of epinephrine and norepinephrine in critically ill patients may trigger a catecholamine storm and contribute to acute kidney injury (AKI) through activation of β-adrenoceptor signaling. Although clinical observations link high-dose catecholamine exposure to increased AKI risk, experimental models and mechanistic studies remain limited. We established a rodent model of combined epinephrine and norepinephrine infusion to investigate the renoprotective effects of subtype-selective β-adrenoceptor blockers. Animals received the β1-selective blockers metoprolol or atenolol, or the β2-selective blocker ICI 118,551. β1-adrenoceptor blockade, particularly with metoprolol, significantly attenuated renal histopathological injury and improved biochemical markers of kidney dysfunction. These protective effects were associated with suppression of ferroptosis-related pathways in the renal cortex. Atenolol partially improved biochemical parameters but did not significantly reduce tubulointerstitial damage, whereas β2-adrenoceptor blockade conferred limited functional benefit despite modest morphological improvement. Collectively, our findings indicate that β1-adrenoceptor activation plays a critical role in catecholamine-induced AKI by promoting ferroptosis. Targeting β1-adrenoceptors, especially with metoprolol, may represent a potential therapeutic strategy for preventing renal injury during catecholamine storms.

Hypoxia during the postnatal period represents a significant risk factor for renal injury in neonates, yet the molecular mechanisms linking oxygen deprivation to kidney damage remain unclear. In this study, we explored whether ferroptosis serves as a key mediator in hypoxia-induced acute kidney injury (AKI). Using a neonatal rat model, we demonstrated that hypoxic exposure disrupts iron homeostasis, leading to iron accumulation and excessive lipid peroxidation in renal tissues. These alterations were associated with marked tubular injury, glomerular damage, and progressive fibrotic remodeling. Importantly, reoxygenation attenuated ferroptosis-related signaling pathways and improved renal structural and functional outcomes, although incomplete recovery was observed in fibrotic changes. Our findings suggest that ferroptosis is not only involved in the initiation of hypoxia-induced renal injury but may also contribute to its progression toward chronic kidney pathology. Targeting ferroptosis and iron metabolism may therefore represent a promising strategy for preventing or treating neonatal hypoxia-related AKI.