Key result
The conventional isoproterenol-induced heart failure model increased in vivo diaphragm excursion by ~30% and ex vivo peak specific force by ~50%, contrary to the dysfunction observed in patients.
Why the study?
Heart failure impairs diaphragm function, but whether the widely used isoproterenol-induced heart failure model presents diaphragmatic dysfunction is unknown.
Does the isoproterenol-induced heart failure model mimic the diaphragmatic dysfunction observed in human heart failure patients?
Does the isoproterenol-induced heart failure model mimic the diaphragmatic dysfunction observed in human heart failure patients?
Effect estimate: increased by ~30%
p-value: p=<0.01
The conventional isoproterenol-induced HF model increases diaphragm contraction, contrary to what is observed in human HF patients, limiting its translational utility for cardio-respiratory interactions.
Isoproterenol HF model fails to replicate human diaphragmatic dysfunction; leaves open its translational utility for cardio-respiratory research.
Heart failure (HF) impairs diaphragm function. Animal models realistically mimicking HF should feature both the cardiac alterations and the diaphragmatic dysfunction characterizing this disease. The isoproterenol-induced HF model is widely used, but whether it presents diaphragmatic dysfunction is unknown. However, indirect data from research in other fields suggest that isoproterenol could increase diaphragm function. The aim of this study was to test the hypothesis that the widespread rodent model of isoproterenol-induced HF results in increased diaphragmatic contractility. Forty C57BL/6J male mice were randomized into 2 groups: HF and healthy controls. After 30 days of isoproterenol infusion to establish HF, in vivo diaphragmatic excursion and ex vivo isolated diaphragm contractibility were measured. As compared with healthy controls, mice with isoproterenol-induced HF showed the expected changes in structural and functional echocardiographic parameters and lung edema. isoproterenol-induced HF increased in vivo diaphragm excursion (by ≈30%, p<0.01) and increased by ≈50% both ex vivo peak specific force (p<0.05) and tetanic force (p<0.05) at almost all 10-100 Hz frequencies (p<0.05), with reduced fatigue resistance (p<0.01) when compared with healthy controls. Expression of myosin genes encoding the main muscle fiber types revealed that Myh4 was higher in isoproterenol-induced HF than in healthy controls (p<0.05), suggesting greater distribution of type IIb fibers. These results show that the conventional isoproterenol-induced HF model increases diaphragm contraction, a finding contrary to what is observed in patients with HF. Therefore, this specific model seems limited for translational an integrative HF research, especially when cardio-respiratory interactions are investigated.
No takes yet. Share an insight, caveat, or question.
Cabrera-Aguilera et al. (2020) studied Heart failure (n=40). Isoproterenol vs. 0.9% NaCl solution was evaluated on In vivo diaphragmatic excursion (increased by ~30%, p=<0.01). The conventional isoproterenol-induced heart failure model increased in vivo diaphragm excursion by ~30% and ex vivo peak specific force by ~50%, contrary to the dysfunction observed in patients.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: