Continuous myofiber remodeling in uninjured extraocular myofibers: Myonuclear turnover and evidence for apoptosis

McLoon, Linda K.; Rowe, Jocelyn; Wirtschafter, Jonathan D.; McCormick, Kathleen

doi:10.1002/mus.20012

Cited by 104 publications

(114 citation statements)

References 51 publications

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“…We confirmed the apoptosis of nuclei of muscle fibers using TUNEL, caspase 3 and laminin B2 co-staining and found the nuclei that were double positive for TUNEL and caspase 3 resided within laminin layer in the diagnostic muscle biopsies from the children. A similar approach has been used to study the myonuclear apoptosis in rabbits [32] and rats [33]. The duration of untreated disease is inversely correlated with clinical symptoms (DAS), which is in agreement with our previous observation [10].…”

Section: Discussionsupporting

confidence: 88%

Apoptosis in the skeletal muscle of untreated children with juvenile dermatomyositis: Impact of duration of untreated disease

Zhao

Fedczyna

McVicker

et al. 2007

Clinical Immunology

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Juvenile Dermatomyositis (JDM) is the most common myopathy in children with characteristic skin rash and muscle weakness, in which longer duration of untreated disease was associated with less muscle weakness. The duration of untreated inflammation may alter the apoptotic pathways involved in skeletal muscle damage. Diagnostic muscle biopsies from 14 untreated patients were stained for apoptosis markers. TUNEL-positive nuclei and caspase 3 were detected within the laminin layer, indicating apoptosis of skeletal muscle nuclei. Untreated JDM disease duration greater than 2 months ("long"), was associated with higher Fas positive cell counts in the perivascular region compared with the "short" disease duration group, 2 months or less. Within the "long" duration group, higher Fas positive cell counts were positively associated with increased TUNEL-positive nuclei and caspase 3. We conclude that the duration of untreated disease (chronic inflammation) influences the mode of continuing cell damage and death in children with JDM.

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Section: Discussionsupporting

confidence: 88%

Apoptosis in the skeletal muscle of untreated children with juvenile dermatomyositis: Impact of duration of untreated disease

Zhao

Fedczyna

McVicker

et al. 2007

Clinical Immunology

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“…The MU size of TA muscle is similar to that reported for the human extraocular muscles, which is about 10 (Ghez, 1991), suggesting a comparable level of control of extraocular and TA muscles. In fact, ILMs share many physiological and anatomical properties with extraocular muscles such as innervation by cranial nerves and muscle fiber remodeling (McLoon et al, 2004;Goding et al, 2005;Hoh, 2005).…”

Section: Discussionmentioning

confidence: 99%

Estimation of the number and size of motor units in intrinsic laryngeal muscles using morphometric methods

Neto¹,

Marques²

2008

Clinical Anatomy

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The number and size of motor units in the intrinsic laryngeal muscles were estimated by morphometric methods. Laryngeal muscles with their respective nerve branches were obtained from 64 fresh cadavers (32 older than 60 years, mean age 74 +/- 9 years and 32 younger than 60 years, mean age 51 +/- 8 years). Myelinated nerve fibers and the total number of muscle fibers were counted. Motor unit size was estimated by dividing the total number of muscle fibers by the total number of motor units in each case. The mean number of motor units ranged from 268 +/- 1.3 (interarytenoid muscle) to 431 +/- 1.6 (cricothyroid muscle). Thyroarytenoid and cricothyroid muscle presented the smallest (9.8 +/- 0.2) and largest (20.5 +/- 0.9) motor unit size, respectively, suggesting that thyroarytenoid muscle has a greater capacity to fine-tune its total force compared with the other intrinsic laryngeal muscles. No differences in motor unit number or size were observed between the right and left sides or between younger and older subjects. It is suggested that synaptic rearrangements may occur at the level of the neuromuscular junction in the human larynx that may explain the age-related changes in motor units reported by clinical methods.

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“…This is reflected, however, in poor proliferation and differentiation of masseter-derived myogenic cells in culture. Satellite cells in the extraocular muscles remain proliferative and add myonuclei to the uninjured myofiber when their limb counterparts are quiescent (McLoon et al 2004), and these muscles are spared in Duchenne muscular dystrophy (Porter et al 2003). These phenomena may be related to specific environmental cues, but the myogenic progenitors themselves may also be different, reflecting their different ontogeny from body muscles.…”

Section: The Journal Of Histochemistry and Cytochemistrymentioning

confidence: 99%

The Skeletal Muscle Satellite Cell: The Stem Cell That Came in From the Cold

Zammit

Partridge

Yablonka–Reuveni

2006

J Histochem Cytochem.

565

496

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The muscle satellite cell was first described and actually named on the basis of its anatomic location under the basement membrane surrounding each myofiber. For many years following its discovery, electron microscopy provided the only definitive method of identification. More recently, several molecular markers have been described that can be used to detect satellite cells, making them more accessible for study at the light microscope level. Satellite cells supply myonuclei to growing myofibers before becoming mitotically quiescent in muscle as it matures. They are then activated from this quiescent state to fulfill their roles in routine maintenance, hypertrophy, and repair of adult muscle. Because muscle is able to efficiently regenerate after repeated bouts of damage, systems must be in place to maintain a viable satellite cell pool, and it was proposed over 30 years ago that self-renewal cell was the primary mechanism. Self-renewal entails either a stochastic event or an asymmetrical division, where one daughter cell is committed to differentiation whereas the second continues to proliferate or becomes quiescent. This classic model of satellite cell self-renewal and the importance of satellite cells in muscle maintenance and repair have been challenged during the past few years as bone marrow-derived cells and various intramuscular populations were shown to be able to contribute myonuclei and occupy the satellite cell niche. This is a fast-moving and dynamic field, however, and in this review we discuss the evidence that we think puts this enigmatic cell firmly back at the center of adult myogenesis. (J Histochem Cytochem 54:1177-1191, 2006)

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Continuous myofiber remodeling in uninjured extraocular myofibers: Myonuclear turnover and evidence for apoptosis

Cited by 104 publications

References 51 publications

Apoptosis in the skeletal muscle of untreated children with juvenile dermatomyositis: Impact of duration of untreated disease

Apoptosis in the skeletal muscle of untreated children with juvenile dermatomyositis: Impact of duration of untreated disease

Estimation of the number and size of motor units in intrinsic laryngeal muscles using morphometric methods

The Skeletal Muscle Satellite Cell: The Stem Cell That Came in From the Cold

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