RESUMEN
The presence of apoptotic fibers and the embryonic proteins desmin and vimentin were investigated in muscle biopsy specimens from patients with spinal muscular atrophy (SMA). Apoptosis was studied in 24 cases of SMA by means of in situ end labeling of nuclear DNA fragmentation using TUNEL staining and immunohistochemistry. Apoptotic nuclei were observed in 54.1% of the cases, and desmin and vimentin positive fibers were found in the majority of cases. A significant negative correlation was observed between the number of apoptotic nuclei and the duration of the disease, as well as between the number of desmin and vimentin positive fibers and the age of onset. These findings indicate that apoptosis, although probably a secondary phenomenon following denervation, plays a role in the progress of spinal muscular atrophy.
Asunto(s)
Apoptosis , Fibras Musculares Esqueléticas/química , Atrofia Muscular Espinal/metabolismo , Niño , Preescolar , Fragmentación del ADN , Desmina/análisis , Femenino , Humanos , Inmunohistoquímica , Etiquetado Corte-Fin in Situ , Lactante , Masculino , Fibras Musculares Esqueléticas/patología , Atrofia Muscular Espinal/patología , Vimentina/análisisRESUMEN
OBJECTIVE: To determine the morphologic and the morphometrical features of spindles in biopsies of patients with different types of muscular dystrophy and investigate the possible involvement of the spindle in the pathologic process of these diseases. STUDY DESIGN: The following variables were studied in biopsy specimens from 10 patients with Duchenne or Becker dystrophy, 9 with limb-girdle dystrophy, 3 with congenital dystrophy and 3 with facioscapulohumeral dystrophy: diameter and area of spindle; thickness of the capsule; number, diameter and area of intrafusal fibers; and number and area of nuclei. RESULTS: The statistical evaluation of the data showed significant differences regarding the thickness of the capsule, which was greater in patients than in controls, while the diameter and the area of the fibers were all smaller in patients than in controls. The area of nuclei of fibers was increased; this was a common feature for all types of muscular dystrophy. CONCLUSION: These findings indicate that the spindle possibly participates in the pathologic process of different types of muscular dystrophies.
Asunto(s)
Husos Musculares/anatomía & histología , Husos Musculares/patología , Distrofias Musculares/patología , Adolescente , Adulto , Niño , Preescolar , Humanos , Persona de Mediana Edad , Distrofia Muscular de Cinturas/patología , Distrofia Muscular de Duchenne/patología , Distrofia Muscular Facioescapulohumeral/patologíaRESUMEN
The developmental status of muscle fibers was investigated in three cases of myotubular myopathy: one infant with the X-linked recessive form and two adult brothers with the autosomal, probably recessive, form of the disease. The presence of the developmentally regulated proteins desmin, vimentin and dystrophin was investigated by immunocytochemistry with the use of monoclonal antibodies. In the X-linked case, intense immunolabelling for vimentin and desmin was observed in the nuclear area of a great number of muscle fibers, while a few others showed sarcoplasmic dystrophin immunolabelling or were dystrophin-negative. In the adult cases, strong desmin immunoreactivity was observed, but only a few fibers labelled for vimentin. Dystrophin sarcolemmal immunolabelling was normal, but in some fibers dystrophin was observed in the area of the central nucleus. These findings are supportive of a maturational arrest of muscle fibers in the X-linked cases and possibly indicative of a similar mechanism in the adult form of centronuclear myopathy in these patients.
Asunto(s)
Proteínas del Citoesqueleto/metabolismo , Miopatías Estructurales Congénitas/metabolismo , Miopatías Estructurales Congénitas/patología , Adulto , Diferenciación Celular , Proteínas del Citoesqueleto/genética , Desmina/genética , Desmina/metabolismo , Distrofina/genética , Distrofina/metabolismo , Humanos , Inmunohistoquímica , Recién Nacido , Masculino , Miopatías Estructurales Congénitas/genética , Hermanos , Vimentina/genética , Vimentina/metabolismoRESUMEN
A study was made of the morphological and morphometrical features of muscle spindles in biopsies of patients with Werdnig-Hoffmann disease (infantile spinal muscular atrophy type I) to investigate the possible involvement of the muscle spindles in the pathological processes of the disease. A total of 57 muscle spindles from 26 cases were studied. The parameters determined were: the diameter and area of spindles, the number, diameter and area of intrafusal fibers, the number and area of nuclei. In addition, the ratio of the area of the intrafusal fibers to the area of nuclei and the ratio of the area of the spindle to the area of the intrafusal fibers were calculated. Statistical evaluation of the data showed significant differences regarding the area of the muscle spindle, the diameter of the intrafusal fibers and the mean area of nuclei of the intrafusal fibers, which were all smaller in patients than in controls (p=0.03, 0.01 and 0.02, respectively), while the thickness of the capsule was greater in patients than in controls (p=0.01). Our results indicate that the muscle spindle participates in the pathological processes of Werdnig-Hoffmann disease.