Histological and ultrastructural findings in the vocal muscles of patients suffering from muscular dystrophies

Abstract

Biopsy material from the vocal muscle of patients suffering from Steinert's muscular dystrophy, Duchenne's muscular dystrophy, oculopharyngeal progressive muscular dystrophy, and paraneoplastic myopathy was examined under the light and electron microscope. The histological findings were compatible with the muscular changes seen in the skeletal muscles of the extremities of the same patients. Slight differences in the severity of the pathologic process were noticed in correlation with the muscles of the extremities which were always more seriously affected than the vocal muscles. The ultrastructural study revealed a moderate to very permanent dilatation of the sarcotubular system, involving the T-tubules and the cisternae of the smooth endoplasmic reticulum as well. From the clinical point of view, the vocal muscle biopsy was beneficial to the patients suffering from Steinert's myotonic muscular dystrophy, whereas it did not affect the clinical condition of the others.

Effect of Recurrent Laryngeal Nerve Section on the Laryngeal Muscles of Adult Rabbits

“…5 In biopsy specimens of laryngeal muscles from patients suffering from myotonic dystrophy, Duchenne's muscular dystrophy, and oculopharyngeal muscular dystrophy, there were minimal variations from the general morphological pattern of the specific muscular dystrophic process. 8 However, although the laryngeal muscles underwent the same alterations, they preserved the cross striations in almost all cases. This recalcitrance to injury was interpreted as an explanation for the prolonged function of the laryngeal muscles even in severe cases of these degenerative diseases.…”

“…All intrinsic laryngeal muscles were involved but less so than the extraocular muscles 5 . In biopsy specimens of laryngeal muscles from patients suffering from myotonic dystrophy, Duchenne's muscular dystrophy, and oculopharyngeal muscular dystrophy, there were minimal variations from the general morphological pattern of the specific muscular dystrophic process 8 . However, although the laryngeal muscles underwent the same alterations, they preserved the cross striations in almost all cases.…”

“…However, although the laryngeal muscles underwent the same alterations, they preserved the cross striations in almost all cases. This recalcitrance to injury was interpreted as an explanation for the prolonged function of the laryngeal muscles even in severe cases of these degenerative diseases 8 …”

Myogenic precursor cells in craniofacial muscles

“…In a study comparing regeneration in the masseter and limb muscles, for example, differing regenerative capacities were linked to intrinsic differences between the muscle precursor cells in these two muscles (Pavlath et al , 1998). The EOM are preferentially spared in patients with Duchenne muscular dystrophy (DMD; Karpati and Carpenter, 1986), and the orbicularis oris, laryngeal (LM) and masticatory (MM) muscles also show less severe alterations in models of DMD (Manolides and Baloyannis, 1981; Kiliaridis and Katsaros, 1998; Muller et al , 2001). In contrast, the MM and EOM are more commonly affected in patients with myasthenia gravis (Oda, 1993; Benveniste et al , 2005).…”

Rat extraocular muscle

“…The mtfltiply-innervated fibers (MIFs) are unique to the EOMs (Hess 1970), inner ear muscles (Veggetti et al 1982), and laryngeal muscles (Manolides and Balogannes 1981). These muscles contain an assortment of singly and multiply-innervated muscle fiber types.…”