Yang L, Li S, Miao L, Huang H, Liang F, Teng X, Xu L, Wang Q, Xiao W, Ridder WH, Ferguson TA, Chen DF, Kaufman RJ, Hu Y.
Rescue of Glaucomatous Neurodegeneration by Differentially Modulating Neuronal Endoplasmic Reticulum Stress Molecules. J Neurosci 2016;36(21):5891-903.
AbstractUNLABELLED: Axon injury is an early event in neurodegenerative diseases that often leads to retrograde neuronal cell death and progressive permanent loss of vital neuronal functions. The connection of these two obviously sequential degenerative events, however, is elusive. Deciphering the upstream signals that trigger the neurodegeneration cascades in both neuronal soma and axon would be a key step toward developing the effective neuroprotectants that are greatly needed in the clinic. We showed previously that optic nerve injury-induced neuronal endoplasmic reticulum (ER) stress plays an important role in retinal ganglion cell (RGC) death. Using two in vivo mouse models of optic neuropathies (traumatic optic nerve injury and glaucoma) and adeno-associated virus-mediated RGC-specific gene targeting, we now show that differential manipulation of unfolded protein response pathways in opposite directions-inhibition of eukaryotic translation initiation factor 2α-C/EBP homologous protein and activation of X-box binding protein 1-promotes both RGC axons and somata survival and preserves visual function. Our results indicate that axon injury-induced neuronal ER stress plays an important role in both axon degeneration and neuron soma death. Neuronal ER stress is therefore a promising therapeutic target for glaucoma and potentially other types of neurodegeneration. SIGNIFICANCE STATEMENT: Neuron soma and axon degeneration have distinct molecular mechanisms although they are clearly connected after axon injury. We previously demonstrated that axon injury induces neuronal endoplasmic reticulum (ER) stress and that manipulation of ER stress molecules synergistically promotes neuron cell body survival. Here we investigated the possibility that ER stress also plays a role in axon degeneration and whether ER stress modulation preserves neuronal function in neurodegenerative diseases. Our results suggest that neuronal ER stress is a general mechanism of degeneration for both neuronal cell body and axon, and that therapeutic targeting of ER stress produces significant functional recovery.
Yao WC, Sedaghat AR, Yadav P, Fay A, Metson R.
Orbital Decompression in the Endoscopic Age: The Modified Inferomedial Orbital Strut. Otolaryngol Head Neck Surg 2016;154(5):963-9.
AbstractOBJECTIVE: Postoperative diplopia occurs in up to 45% of patients following orbital decompression for exophthalmos associated with Graves' orbitopathy. We sought to describe outcomes of our balanced orbital decompression strategy that includes the preservation of a modified inferomedial orbital strut (mIOS). STUDY DESIGN: Case series with chart review. SETTING: Academic medical center. SUBJECTS AND METHODS: A total of 115 consecutive orbital decompressions were performed on 73 patients (42 bilateral) with Graves' orbitopathy. All patients underwent (1) a balanced decompression technique incorporating an endoscopic medial and external lateral decompression and (2) a mIOS technique with preservation of the anterior half of the inferomedial orbital strut. A periorbital periosteal (orbital) sling was utilized in patients (n = 54) without threatened vision loss, proptosis >28 mm, or periorbital disruption to prevent prolapse of the medial rectus muscle. RESULTS: Utilization of the mIOS technique with or without a sling did not adversely affect the reduction in proptosis (5.1 mm with sling vs 5.0 mm without sling; P = .85).The incidence of new-onset postoperative diplopia was 17% (n = 6). The sling was not associated with postoperative diplopia (odds ratio = 0.54, 95% confidence interval: 0.08-3.40, P = .51), while it was associated with resolution of preexisting diplopia (odds ratio = 6.67, 95% confidence interval: 1.06-42.06, P = .04). No intraoperative complications occurred, and no patients suffered a decrement in visual acuity. CONCLUSION: Balanced orbital decompression utilizing a mIOS in patients with Graves' orbitopathy provides a safe and effective reduction in proptosis with a low rate of new-onset diplopia as compared with historical values. Utilization of an orbital sling may be beneficial in reducing postoperative diplopia in select patients.