Ming-Hui Sun

Retinal Protection from Acute Glaucoma-Induced Ischemia-Reperfusion Injury through Pharmacologic Induction of Heme Oxygenase-1

PURPOSEnTo investigate the protective effects of cobalt protoporphyrin (CoPP), a potent heme oxygenase (HO)-1 inducer, in a rat model of ischemia-reperfusion injury and to document the possible antiapoptotic and anti-inflammatory mechanisms underlying the protection.nnnMETHODSnRats pretreated with intraperitoneal injection of CoPP (5 mg/kg) were subjected to retinal ischemia by increases in intraocular pressure to 130 mm Hg for 60 minutes. The protective effects of CoPP were evaluated by determining the morphology of the retina, counting the survival of retinal ganglion cells (RGCs), and measuring apoptosis in retinal layers. In addition, expressions of HO-1, caspase-3, p53, Bcl-xL, monocyte chemoattractant protein (MCP)-1, and inducible nitric oxide synthase (iNOS) were documented by Western blot analysis. Detection of HO-1, NF-kappaB, and CD68 protein in the retina was performed by immunohistochemistry or immunofluorescence.nnnRESULTSnPharmacologic induction of HO-1 by CoPP led to HO-1 expression in the full retinal layer. HO-1 overexpression alleviated apoptosis in the retina, preserved RGCs, and attenuated the reduction of inner retinal thickness after ischemia-reperfusion injury. Concurrently, overexpression of HO-1 was associated with inhibition of caspase-3, p53, NF-kappaB, and iNOS and with increased expression of Bcl-xL. Meanwhile, the anti-inflammatory effect of HO-1 was related to reduction in the recruitment of macrophage infiltration in the retina through the suppression of MCP-1. These beneficial effects of HO-1 induced by CoPP were diminished by the HO-1 inhibitor ZnPP.nnnCONCLUSIONSnOverexpression of HO-1 by pharmacologic induction protected the retina from subsequent cellular damage caused by ischemia-reperfusion injury through antiapoptotic and anti-inflammatory effects.

Efficacy and Safety of Biodegradable Collagen-Glycosaminoglycan Polymer as a Material for Scleral Buckling

PURPOSEnTo test the efficacy and safety of a biodegradable collagen-glycosaminoglycan (CG) polymer as the material for scleral buckling in rabbit eyes.nnnMETHODSnSegmental scleral buckling was performed by using a silicone sponge in one eye and a biodegradable CG polymer in the other eye of 20 rabbits. Wound and conjunctival reactions were evaluated by external photographs 1 day and then every week after surgery. Echography was used to evaluate the extent of the buckling effect. Electroretinograms were used to evaluate the retinal function after scleral buckling. Histology and immunohistochemistry were used to check the tissue reaction and distribution of myofibroblasts during wound healing. Scanning electronic microscopy of buckling materials was used to analyze structural changes after episcleral implantation.nnnRESULTSnBiodegradable collagen initially achieved a buckling effect comparable to a silicone sponge; the buckling effect decreased after 1 month. Within 8 to 12 weeks, the collagen was gradually absorbed. After implantation, the collagen matrix degraded, and the pore size decreased as a result of compression and degradation. In contrast, no major structural changes were observed in silicone sponges, except some cell debris, fibrin, and blood cells were detected inside the porous structure of the sponge. The inflammatory responses were comparable between sponge and collagen in most areas of peribuckling histology. In areas of degraded collagen, a foreign body reaction was observable. Electroretinography revealed no detectable difference in retinal function between control and experimental eyes.nnnCONCLUSIONSnBiodegradable collagen was used effectively and safely as a material for scleral buckling.

Rare ocular features in a case of Kabuki syndrome (Niikawa-Kuroki syndrome)

BackgroundKabuki syndrome is a multi-system disorder with peculiar facial features, and ophthalmic abnormalities are frequently involved. This case report of a child with Kabuki syndrome describes two new previously unreported ophthalmic conditions.Case presentationA 3-year-old Taiwanese boy with Kabuki syndrome had a short stature, spinal dysraphism, intellectual disability and typical facial features. Ophthalmic findings which have been previously reported in the literature and in this patient, included ptosis, esotropia, coloboma of the iris, retina, choroid and optic disc, and microcornea. The newly identified ophthalmic features in this patient included colobomatous microphthalmos and a dysplastic and elevated disc without central cupping. The genetic analysis identified an MLL2 gene mutation.ConclusionThe presentations of a dysplastic disc and colobomatous microphthalmia are rarely reported in patients with Kabuki syndrome, but these ophthalmic abnormalities may affect vision. Detailed ophthalmic evaluations in children with Kabuki syndrome are advised.

Nonarteritic anterior ischaemic optic neuropathy and its association with obstructive sleep apnoea: a health insurance database study

Nonarteritic anterior ischaemic optic neuropathy (NAION) is the most common acute optic neuropathy in old age. Although there are several known risk factors, the influence of obstructive sleep apnoea (OSA) has not been completely elucidated. The aim of this study was to evaluate the association between NAION and OSA.