Early and continued manual stimulation is required for long‐term recovery after facial nerve injury

Grosheva, Maria; Rink, Svenja; Jansen, Ramona; Bendella, Habib; Pavlov, Stoyan; Sarıkcıoğlu, Levent; Angelov, Doychin N.; Dunlop, Sarah

doi:10.1002/mus.25613

Cited by 4 publications

(1 citation statement)

References 57 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Although reinnervation occurs relatively fast in our model, the proportion of poly-innervated NMJs remained significantly increased for up to three months after nerve damage. This observation is consistent with experiments showing that some facial muscles maintain a significant percentage of poly-innervated NMJs (~ 16%) after muscle reinnervation [ 40 ]. Moreover, in some frog species, there is a significant percentage of poly-innervated muscle fibers in adult stages [ 41 ].…”

Section: Discussionsupporting

confidence: 92%

Functional regeneration of the murine neuromuscular synapse relies on long-lasting morphological adaptations

et al. 2022

View full text Add to dashboard Cite

Background In a broad variety of species, muscle contraction is controlled at the neuromuscular junction (NMJ), the peripheral synapse composed of a motor nerve terminal, a muscle specialization, and non-myelinating terminal Schwann cells. While peripheral nerve damage leads to successful NMJ reinnervation in animal models, muscle fiber reinnervation in human patients is largely inefficient. Interestingly, some hallmarks of NMJ denervation and early reinnervation in murine species, such as fragmentation and poly-innervation, are also phenotypes of aged NMJs or even of unaltered conditions in other species, including humans. We have reasoned that rather than features of NMJ decline, such cellular responses could represent synaptic adaptations to accomplish proper functional recovery. Here, we have experimentally tackled this idea through a detailed comparative study of the short- and long-term consequences of irreversible (chronic) and reversible (partial) NMJ denervation in the convenient cranial levator auris longus muscle. Results Our findings reveal that irreversible muscle denervation results in highly fragmented postsynaptic domains and marked ectopic acetylcholine receptor clustering along with significant terminal Schwann cells sprouting and progressive detachment from the NMJ. Remarkably, even though reversible nerve damage led to complete reinnervation after 11 days, we found that more than 30% of NMJs are poly-innervated and around 65% of postsynaptic domains are fragmented even 3 months after injury, whereas synaptic transmission is fully recovered two months after nerve injury. While postsynaptic stability was irreversibly decreased after chronic denervation, this parameter was only transiently affected by partial NMJ denervation. In addition, we found that a combination of morphometric analyses and postsynaptic stability determinations allows discriminating two distinct forms of NMJ fragmentation, stable-smooth and unstable-blurred, which correlate with their regeneration potential. Conclusions Together, our data unveil that reversible nerve damage imprints a long-lasting reminiscence in the NMJ that results in the rearrangement of its cellular components. Instead of being predictive of NMJ decline, these traits may represent an efficient adaptive response for proper functional recovery. As such, these features are relevant targets to be considered in strategies aimed to restore motor function in detrimental conditions for peripheral innervation.

show abstract

Section: Discussionsupporting

confidence: 92%

Functional regeneration of the murine neuromuscular synapse relies on long-lasting morphological adaptations

et al. 2022

View full text Add to dashboard Cite

show abstract

Ischemic stroke-induced polyaxonal innervation at the neuromuscular junction is attenuated by robot-assisted mechanical therapy

Balch

Harris

Chugh

et al. 2021

Experimental Neurology

View full text Add to dashboard Cite

Facial Nerve Repair by Muscle-Vein Conduit in Rats: Functional Recovery and Muscle Reinnervation

Μanthou

Gencheva

Sinis

et al. 2021

Tissue Engineering Part A

View full text Add to dashboard Cite

Early and continued manual stimulation is required for long‐term recovery after facial nerve injury

Abstract: Early and continued MS results in better recovery than when it is either discontinued or delayed. Muscle Nerve 57: 100-106, 2018.

Cited by 4 publications

References 57 publications

Functional regeneration of the murine neuromuscular synapse relies on long-lasting morphological adaptations

Functional regeneration of the murine neuromuscular synapse relies on long-lasting morphological adaptations

Ischemic stroke-induced polyaxonal innervation at the neuromuscular junction is attenuated by robot-assisted mechanical therapy

Facial Nerve Repair by Muscle-Vein Conduit in Rats: Functional Recovery and Muscle Reinnervation

Contact Info

Product

Resources

About