Increased Frequency of Activated Satellite Cells in Overacting Inferior Oblique Muscles from Humans

Abstract

The presence of an increased number of activated SCs in overacting IOMs of the strabismic group in contrast to the frequency in the control group resembles the findings detected in developing, regenerating, or hypertrophic muscle tissue. High levels of MyoD1- and myogenin-positive SC in overacting IOMs support the hypothesis that these cells may be involved in alterations in IOM structure correlated with the overaction observed clinically.

Bupivacaine injection of eye muscles to treat strabismus

“…4 5 The participation of satellite cells in eye muscle function and the signals that control their activation are related fields of great interest. 16 17 We suppose that the strabismus after cataract surgery also results from muscle hypertrophy induced by bupivacaine. 18 Fibrosis and Figure 1 The patient immediately after bupivacaine injection (above), and at 33 days after injection (below).…”

Effects of Recession versus Tenotomy Surgery without Recession in Adult Rabbit Extraocular Muscle

“…The differential reactivity of satellite cell populations in surgical specimens from strabismus patients with the same diagnosis supports the hypothesis that individual EOM responses to perturbations differ from each other and from control EOM. 10,11 In overacting inferior oblique muscles, there are elevated numbers of activated satellite cells. 10 In overacting patient medial rectus muscles there are decreased numbers of activated satellite cells, and in underacting muscles, these numbers increase.…”

“…10,11 In overacting inferior oblique muscles, there are elevated numbers of activated satellite cells. 10 In overacting patient medial rectus muscles there are decreased numbers of activated satellite cells, and in underacting muscles, these numbers increase. 11 Satellite cell reactivity in EOMs under all these conditions may reflect differences between patients that are significant and difficult to control: age at time of surgery, the duration of strabismus from time of onset to time of surgery, whether previous surgery had been performed, hormonal state, 15 efferent tonus, and so forth.…”

“…This finding suggests that there are likely to be multiple underlying causes of EOM dysfunction that are quite distinct from one another. 9 Other studies demonstrate that the EOMs from strabismus patients appear to adapt to cues received from the ocular motor system in the brain that control their motor behavior, 10,11 as their satellite cell populations are in a constant state of flux. These studies suggest that the EOMs react to surgical interventions and that these adaptations could be assessed and potentially manipulated with a goal of improved surgical outcomes.…”

Variações no posicionamento dos eixos visuais em pacientes submetidos a cirurgias de estrabismo

“…Se por um lado há um aumento no número de células satélites em músculos oblíquos hiperfuncionantes (22) , o mesmo não ocorre em músculos retos mediais também considerados hiperfuncionantes de pacientes portadores de esotropia de aparecimento precoce (23) . A hiperelevação do olho em adução observada em pacientes com hiperfunção de oblíquos inferiores e em pacientes com craniossinostose mostra alterações distintas na anatomia das miofibras desses músculos, evidenciando que etiologias diferentes de estrabismo podem levar a respostas diferentes da musculatura extraocular após cirurgias para correção de estrabismo (24)(25) .…”