title: Physical exercise reduces cardiac defects in type 2 spinal muscular atrophy-like mice.
abstract: Spinal muscular atrophy (SMA), the leading genetic cause of death in infants worldwide, is due to the misexpression of the survival of motor neuron protein, causing death of motor neurons. Several clinical symptoms suggested that, in addition to motor neurons, the autonomic nervous systems could be implicated in the cardiac function alterations observed in patienst with SMA. These alterations were also found in a severe SMA mouse model, including bradycardia and a reduction of sympathetic innervation, both associated with autonomic imbalance. In the present study, we investigate the extent of autonomic dysfunction and the effects of a running-based exercise on the altered cardiorespiratory function in type 2 SMA-like mice. We observed that the SMA induced: (1) a dramatic alteration of intrinsic cardiac conduction associated with bradycardia; (2) a severe cardiomyopathy associated with extensive ventricular fibrosis; and (3) a delay in cardiac muscle maturation associated with contractile protein expression defects. Furthermore, our data indicate that the sympathetic system is not only functioning, but also likely contributes to alleviate the bradycardia and the arrhythmia in SMA-like mice. Moreover, physical exercise provides many benefits, including the reduction of cardiac protein expression defect, the reduction of fibrosis, the increase in cardiac electrical conduction velocity, and the drastic reduction in bradycardia and arrhythmias resulting in the partial restoration of the cardiac function in these mice. Thus, modulating the cardiorespiratory function in SMA could represent a new target for improving supportive care and for developing new pharmacological and non-pharmacological interventions that would most certainly include physical exercise.
authors.affiliation: Universite Paris Descartes - CESEM UMR 8194, 45 rue des Saints Peres, Paris 75006, France. olivier.biondi@parisdescartes.fr
authors.forename: Olivier
authors.initials: O
authors.lastname: Biondi
authors.forename: Philippe
authors.initials: P
authors.lastname: Lopes
authors.forename: Céline
authors.initials: C
authors.lastname: Desseille
authors.forename: Julien
authors.initials: J
authors.lastname: Branchu
authors.forename: Farah
authors.initials: F
authors.lastname: Chali
authors.forename: Amina
authors.initials: A
authors.lastname: Ben Salah
authors.forename: Claude
authors.initials: C
authors.lastname: Pariset
authors.forename: Christophe
authors.initials: C
authors.lastname: Chanoine
authors.forename: Frédéric
authors.initials: F
authors.lastname: Charbonnier
mesh_terms: D000818:Animals; D001919:Bradycardia / Q000235:genetics / Q000503:physiopathology*; D003285:Contractile Proteins / Q000235:genetics / Q000378:metabolism; D005355:Fibrosis / Q000235:genetics / Q000503:physiopathology*; D015870:Gene Expression; D006352:Heart Ventricles / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology; D051379:Mice; D008822:Mice, Transgenic; D005082:Physical Exertion; D012420:Running; D014897:Spinal Muscular Atrophies of Childhood / Q000235:genetics / Q000503:physiopathology*; D055533:Survival of Motor Neuron 1 Protein / Q000235:genetics; D013564:Sympathetic Nervous System / Q000503:physiopathology
chemical_list: D003285:Contractile Proteins; D055533:Survival of Motor Neuron 1 Protein