Ventilator-induced diaphragmatic dysfunction in MDX mice

Abstract

Introduction: Patients with Duchenne muscular dystrophy (DMD) frequently undergo mechanical ventilation (MV) for treatment of hypoventilation, but the susceptibility of the dystrophic diaphragm to ventilator-induced diaphragmatic dysfunction (VIDD) has not been examined.

Methods: Dystrophic mice (mdx-genetic homolog of DMD) were assigned to non-ventilated control (CTL) and MV (for 6 hours) groups. Biochemical markers of oxidative/cellular stress, metabolism, and proteolysis were compared along with ex-vivo diaphragmatic force production.

Results: MV significantly depressed maximal diaphragmatic force production compared with baseline values. In addition, MV triggered oxidative stress responses, STAT3 phosphorylation, and an upregulation of cellular pathways associated with muscle proteolysis and/or wasting (autophagy, E3 ubiquitin ligases, and myostatin).

Discussion: Short-term MV induces rapid diaphragmatic force loss and biochemical changes consistent with VIDD in mdx mice. This may have implications for the optimal use of intermittent MV in DMD patients. Muscle Nerve 57: 442-448, 2018.

Keywords: Duchenne muscular dystrophy; VIDD; diaphragm disuse; home mechanical ventilation; mdx mice; neuromuscular disorder.