January 2016

Jun G, Ibrahim-Verbaas CA, Vronskaya M, Lambert J-C, Chung J, Naj AC, Kunkle BW, Wang L-S, Bis JC, Bellenguez C, Harold D, Lunetta KL, Destefano AL, Grenier-Boley B, Sims R, Beecham GW, Smith AV, Chouraki V, Hamilton-Nelson KL, Ikram MA, Fievet N, Denning N, Martin ER, Schmidt H, Kamatani Y, Dunstan ML, Valladares O, Laza AR, Zelenika D, Ramirez A, Foroud TM, Choi S-H, Boland A, Becker T, Kukull WA, van der Lee SJ, Pasquier F, Cruchaga C, Beekly D, Fitzpatrick AL, Hanon O, Gill M, Barber R, Gudnason V, Campion D, Love S, Bennett DA, Amin N, Berr C, Tsolaki M, Buxbaum JD, Lopez OL, Deramecourt V, Fox NC, Cantwell LB, Tárraga L, Dufouil C, Hardy J, Crane PK, Eiriksdottir G, Hannequin D, Clarke R, Evans D, Mosley TH, Letenneur L, Brayne C, Maier W, De Jager P, Emilsson V, Dartigues J-F, Hampel H, Kamboh MI, de Bruijn RFAG, Tzourio C, Pastor P, Larson EB, Rotter JI, O'Donovan MC, Montine TJ, Nalls MA, Mead S, Reiman EM, Jonsson PV, Holmes C, St George-Hyslop PH, Boada M, Passmore P, Wendland JR, Schmidt R, Morgan K, Winslow AR, Powell JF, Carasquillo M, Younkin SG, Jakobsdóttir J, Kauwe JSK, Wilhelmsen KC, Rujescu D, Nöthen MM, Hofman A, Jones L, Jones L, Haines JL, Psaty BM, Van Broeckhoven C, Holmans P, Launer LJ, Mayeux R, Lathrop M, Goate AM, Escott-Price V, Seshadri S, Pericak-Vance MA, Amouyel P, Williams J, van Duijn CM, Schellenberg GD, Farrer LA. A novel Alzheimer disease locus located near the gene encoding tau protein. Mol Psychiatry 2016;21(1):108-117.Abstract

APOE ɛ4, the most significant genetic risk factor for Alzheimer disease (AD), may mask effects of other loci. We re-analyzed genome-wide association study (GWAS) data from the International Genomics of Alzheimer's Project (IGAP) Consortium in APOE ɛ4+ (10 352 cases and 9207 controls) and APOE ɛ4- (7184 cases and 26 968 controls) subgroups as well as in the total sample testing for interaction between a single-nucleotide polymorphism (SNP) and APOE ɛ4 status. Suggestive associations (P<1 × 10(-4)) in stage 1 were evaluated in an independent sample (stage 2) containing 4203 subjects (APOE ɛ4+: 1250 cases and 536 controls; APOE ɛ4-: 718 cases and 1699 controls). Among APOE ɛ4- subjects, novel genome-wide significant (GWS) association was observed with 17 SNPs (all between KANSL1 and LRRC37A on chromosome 17 near MAPT) in a meta-analysis of the stage 1 and stage 2 data sets (best SNP, rs2732703, P=5·8 × 10(-9)). Conditional analysis revealed that rs2732703 accounted for association signals in the entire 100-kilobase region that includes MAPT. Except for previously identified AD loci showing stronger association in APOE ɛ4+ subjects (CR1 and CLU) or APOE ɛ4- subjects (MS4A6A/MS4A4A/MS4A6E), no other SNPs were significantly associated with AD in a specific APOE genotype subgroup. In addition, the finding in the stage 1 sample that AD risk is significantly influenced by the interaction of APOE with rs1595014 in TMEM106B (P=1·6 × 10(-7)) is noteworthy, because TMEM106B variants have previously been associated with risk of frontotemporal dementia. Expression quantitative trait locus analysis revealed that rs113986870, one of the GWS SNPs near rs2732703, is significantly associated with four KANSL1 probes that target transcription of the first translated exon and an untranslated exon in hippocampus (P⩽1.3 × 10(-8)), frontal cortex (P⩽1.3 × 10(-9)) and temporal cortex (P⩽1.2 × 10(-11)). Rs113986870 is also strongly associated with a MAPT probe that targets transcription of alternatively spliced exon 3 in frontal cortex (P=9.2 × 10(-6)) and temporal cortex (P=2.6 × 10(-6)). Our APOE-stratified GWAS is the first to show GWS association for AD with SNPs in the chromosome 17q21.31 region. Replication of this finding in independent samples is needed to verify that SNPs in this region have significantly stronger effects on AD risk in persons lacking APOE ɛ4 compared with persons carrying this allele, and if this is found to hold, further examination of this region and studies aimed at deciphering the mechanism(s) are warranted.

Katikireddy KR, Jurkunas UV. Limbal Stromal Tissue Specific Stem Cells and Their Differentiation Potential to Corneal Epithelial Cells. Methods Mol Biol 2016;1341:437-44.Abstract

From the derivation of the first human embryonic stem (hES) cell line to the development of induced pluripotent stem (iPS) cells; it has become evident that tissue specific stem cells are able to differentiate into a specific somatic cell types. The understanding of key processes such as the signaling pathways and the role of the microenvironment in epidermal/epithelial development has provided important clues for the derivation of specific epithelial cell types.Various differentiation protocols/methods were used to attain specific epithelial cell types. Here, we describe in detail the procedure to follow for isolation of tissue specific stem cells, mimicking their microenvironment to attain stem cell characteristics, and their potential differentiation to corneal epithelial cells.

Kumase F, Takeuchi K, Morizane Y, Suzuki J, Matsumoto H, Kataoka K, Al-Moujahed A, Maidana DE, Miller JW, Vavvas DG. AMPK-Activated Protein Kinase Suppresses Ccr2 Expression by Inhibiting the NF-κB Pathway in RAW264.7 Macrophages. PLoS One 2016;11(1):e0147279.Abstract

C-C chemokine receptor 2 (Ccr2) is a key pro-inflammatory marker of classic (M1) macrophage activation. Although Ccr2 is known to be expressed both constitutively and inductively, the full regulatory mechanism of its expression remains unclear. AMP-activated protein kinase (AMPK) is not only a master regulator of energy homeostasis but also a central regulator of inflammation. In this study, we sought to assess AMPK's role in regulating RAW264.7 macrophage Ccr2 protein levels in resting (M0) or LPS-induced M1 states. In both M0 and M1 RAW264.7 macrophages, knockdown of the AMPKα1 subunit by siRNA led to increased Ccr2 levels whereas pharmacologic (A769662) activation of AMPK, attenuated LPS-induced increases in Ccr2 expression in an AMPK dependent fashion. The increases in Ccr2 levels by AMPK downregulation were partially reversed by NF-κB inhibition whereas TNF-a inhibition had minimal effects. Our results indicate that AMPK is a negative regulator of Ccr2 expression in RAW264.7 macrophages, and that the mechanism of action of AMPK inhibition of Ccr2 is mediated, in part, through the NF-κB pathway.

Ma KN, Thanos A, Chodosh J, Shah AS, Mantagos IS. A Novel Technique for Amniotic Membrane Transplantation in Patients with Acute Stevens-Johnson Syndrome. Ocul Surf 2016;14(1):31-6.Abstract

Cryopreserved amniotic membrane (AM) transplantation is an emerging technique that is becoming the gold standard for the management of acute Stevens-Johnson syndrome (SJS) and its more severe variant, toxic epidermal necrolysis (TEN). We describe a novel surgical technique utilizing a single, large sheet of AM (5 x 10 cm) and a custom-made forniceal ring, which facilitates AM placement. Our technique is easy to use and minimizes suturing and manipulation of ocular tissues, resulting in decreased operative time. This technique may be applied in the management of multiple ocular surface disease processes, including chemical or thermal burns, severe ocular graft versus host disease (GVHD), and other autoimmune diseases.


PURPOSE: To report swept-source optical coherence tomography findings of sarcoid choroidal granulomas in the posttreatment convalescent stage of disease. PATIENTS/METHODS: The authors retrospectively reviewed charts from patients with sarcoid-related choroidal granulomas and recorded pertinent examination and imaging findings. Swept-source optical coherence tomography was performed using the DRI 3D-OCT-1 Atlantis (Topcon) over the areas of previous choroidal granulomas after the patients had been treated. RESULTS: Three patients with sarcoid choroidal granulomas were imaged with swept-source optical coherence tomography. Findings included loss or alteration of choroidal architecture, subretinal fibrosis, and outer retinal tubulations in the areas of the sarcoid granulomas after treatment. In one case with an associated choroidal neovascular membrane, there was also disruption of Bruch membrane and loss of normal choroidal vascular network in the area of the lesion. CONCLUSION: Swept-source optical coherence tomography demonstrated significant anatomical sequelae that persisted after treatment of sarcoid granulomas. To the best of the authors' knowledge, this is the first report of outer retinal tubulations over healed sarcoid granulomas.

Silpa-Archa S, Lee JJ, Foster SC. Ocular manifestations in systemic lupus erythematosus. Br J Ophthalmol 2016;100(1):135-41.Abstract

Systemic lupus erythematosus (SLE) can involve many parts of the eye, including the eyelid, ocular adnexa, sclera, cornea, uvea, retina and optic nerve. Ocular manifestations of SLE are common and may lead to permanent blindness from the underlying disease or therapeutic side effects. Keratoconjunctivitis sicca is the most common manifestation. However, vision loss may result from involvement of the retina, choroid and optic nerve. Ocular symptoms are correlated to systemic disease activity and can present as an initial manifestation of SLE. The established treatment includes prompt systemic corticosteroids, steroid-sparing immunosuppressive drugs and biological agents. Local ocular therapies are options with promising efficacy. The early recognition of disease and treatment provides reduction of visual morbidity and mortality.

Sparrow JR, Duncker T, Woods R, Delori FC. Quantitative Fundus Autofluorescence in Best Vitelliform Macular Dystrophy: RPE Lipofuscin is not Increased in Non-Lesion Areas of Retina. Adv Exp Med Biol 2016;854:285-90.Abstract

Since the lipofuscin of retinal pigment epithelial (RPE) cells has been implicated in the pathogenesis of Best vitelliform macular dystrophy, we quantified fundus autofluorescence (quantitative fundus autofluorescence, qAF) as an indirect measure of RPE lipofuscin levels. Mean non-lesion qAF was found to be within normal limits for age. By spectral domain optical coherence tomography (SD-OCT) vitelliform lesions presented as fluid-filled subretinal detachments containing reflective material. We discuss photoreceptor outer segment debris as the source of the intense fluorescence of these lesions and loss of anion channel functioning as an explanation for the bullous photoreceptor-RPE detachment. Unexplained is the propensity of the disease for central retina.

Stagner AM, Jakobiec FA. Peripheral Nerve Sheath Tumors of the Eyelid Dermis: A Clinicopathologic and Immunohistochemical Analysis. Ophthal Plast Reconstr Surg 2016;32(1):40-5.Abstract

PURPOSE: To determine the incidences, clinical features, and detailed histopathologic and immunohistochemical findings of 10 peripheral nerve tumors (isolated neurofibromas, solitary circumscribed neuromas [SCNs], and schwannomas) localized to the eyelid dermis. METHODS: In this retrospective clinicopathologic study, clinical records and paraffin sections subjected to hematoxylin and eosin, Masson trichrome, periodic acid-Schiff, reticulin, and Alcian blue staining were critically reviewed from each case. Additional paraffin sections were immunoreacted for S100, neurofilament, CD34, epithelial membrane antigen (EMA), glucose transporter-1 (glut-1), and calretinin. RESULTS: Ten patients with a median age of 57 years had solitary, small, flesh-colored papules, 70% at the eyelid margin. Microscopically, they were diagnosed either as a SCN or an isolated neurofibroma. SCN was diffusely S100-positive (and sometimes diffusely calretinin-positive) with myriad neurofilaments. Fascicles of cells were separated by CD34-positive septa, and the lesions were surrounded by a glut-1/EMA-positive capsule. Neurofibromas were calretinin-negative and had a moderate number of S100-positive cells, with widely scattered neurofilaments, many CD34-postive intermixed cells, and no capsule. No schwannomas were diagnosed. CONCLUSIONS: Peripheral nerve tumors of the eyelid have a distinct clinical presentation at the eyelid margin. Careful histopathologic and immunohistochemical studies can reliably separate the entities in the categories of isolated neurofibroma, SCN, and schwannoma when the last occurs. These distinctions can have important systemic implications.

Tabebordbar M, Zhu K, Cheng JKW, Chew WL, Widrick JJ, Yan WX, Maesner C, Wu EY, Xiao R, Ran AF, Cong L, Zhang F, Vandenberghe LH, Church GM, Wagers AJ. In vivo gene editing in dystrophic mouse muscle and muscle stem cells. Science 2015;Abstract

Frame-disrupting mutations in the DMD gene, encoding dystrophin, compromise myofiber integrity and drive muscle deterioration in Duchenne muscular dystrophy (DMD). Removing one or more exons from the mutated transcript can produce an in-frame mRNA and a truncated, but still functional, protein. In this study, we develop and test a direct gene-editing approach to induce exon deletion and recover dystrophin expression in the mdx mouse model of DMD. Delivery by adeno-associated virus (AAV) of clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 endonucleases coupled with paired guide RNAs flanking the mutated Dmd exon23 resulted in excision of intervening DNA and restored Dystrophin reading frame in myofibers, cardiomyocytes, and muscle stem cells following local or systemic delivery. AAV-Dmd CRISPR-treatment partially recovered muscle functional deficiencies and generated a pool of endogenously corrected myogenic precursors in mdx mouse muscle.

Taub DG, Liu Q. The Role of Intraflagellar Transport in the Photoreceptor Sensory Cilium. Adv Exp Med Biol 2016;854:627-33.Abstract

The photoreceptor is a complex specialized cell in which a major component responsible for visual transduction is the photoreceptor sensory cilium (PSC). Building and maintenance of the PSC requires the transport of large proteins along microtubules that extend from the inner segments to the outer segments. A key process, termed intraflagellar transport (IFT), has been recognized as an essential phenomenon for photoreceptor development and maintenance, and exciting new studies have highlighted its importance in retinal and cilia related diseases. This review focuses on the important roles of IFT players, including motor proteins, IFT proteins, and photoreceptor-specific cargos in photoreceptor sensory cilium. In addition, specific IFT components that are involved in inherited human diseases are discussed.

Tiedemann LM, Manley P, Smith ER, Dagi LR. Visual Field Loss in a Case of Recurrent Cystic Craniopharyngioma During Concomitant Treatment With Pegylated Interferon α-2b. J Pediatr Hematol Oncol 2015;Abstract

A 13-year-old male with suprasellar cystic craniopharyngioma initially controlled with sequential subtotal resections and proton-beam irradiation was later treated with intracystic pegylated interferon α-2b due to progression and a lack of further surgical options. After initial successful control of recurrent cyst enlargement and stabilization of the ophthalmic examination, progressive and irreversible visual field loss ensued. Imaging revealed intracranial leakage from the intracystic catheter, and direct administration of interferon α-2b was discontinued. Given the recent interest in interferon α-2b, oncologists are advised to vigilantly monitor patients for signs of local toxicity that may result from unintended leakage during intracystic delivery.

Vodopivec I, Prasad S. Treatment of Susac Syndrome. Curr Treat Options Neurol 2016;18(1):3.Abstract

OPINION STATEMENT: Susac syndrome is a microangiopathy of the brain, retina, and cochlea. Several lines of evidence support the concept that this disease is an acquired autoimmune disorder. Prospective, randomized, controlled studies of treatments are not available because the disease is rare. Furthermore, the average period of follow-up in reported cases is short, limiting a complete understanding of the natural history of the disease. Empirical treatment strategies are therefore based upon expert recommendations and anecdotal reports of response to various immunomodulators, and the appropriate duration of therapy is not known. In our opinion, the encephalopathic form of Susac syndrome should be treated early and aggressively to avoid cognitive dysfunction and disability. Induction therapy with pulse methylprednisolone frequently proves to be inadequate. Additional agents, including intravenous immunoglobulins, intravenous cyclophosphamide, or rituximab are often necessary to induce a sustained remission. Maintenance therapy with oral glucocorticoids combined with intravenous immunoglobulins, mycophenolate mofetil, methotrexate, azathioprine, cyclophosphamide, or rituximab is typically necessary to achieve a sustained remission. Aspirin may be used as an adjunctive agent, although evidence showing efficacy is scant. The response to treatment should be closely monitored by frequent clinical examinations, brain MRI, and fluorescein angiography. Once disease remission has been established, it appears prudent to continue maintenance treatment for at least two additional years, although the real long-term risk of future relapses remains unknown. Establishing a multicenter patient registry and biorepository is essential to study the pathogenesis of the disease, further define the duration of disease, identify reliable biomarkers that aid early diagnosis and assess risk of relapse, and develop effective disease-specific therapies.

Wen G, Aizenman A, Drew T, Wolfe JM, Haygood TM, Markey MK. Computational assessment of visual search strategies in volumetric medical images. J Med Imaging (Bellingham) 2016;3(1):015501.Abstract

When searching through volumetric images [e.g., computed tomography (CT)], radiologists appear to use two different search strategies: "drilling" (restrict eye movements to a small region of the image while quickly scrolling through slices), or "scanning" (search over large areas at a given depth before moving on to the next slice). To computationally identify the type of image information that is used in these two strategies, 23 naïve observers were instructed with either "drilling" or "scanning" when searching for target T's in 20 volumes of faux lung CTs. We computed saliency maps using both classical two-dimensional (2-D) saliency, and a three-dimensional (3-D) dynamic saliency that captures the characteristics of scrolling through slices. Comparing observers' gaze distributions with the saliency maps showed that search strategy alters the type of saliency that attracts fixations. Drillers' fixations aligned better with dynamic saliency and scanners with 2-D saliency. The computed saliency was greater for detected targets than for missed targets. Similar results were observed in data from 19 radiologists who searched five stacks of clinical chest CTs for lung nodules. Dynamic saliency may be superior to the 2-D saliency for detecting targets embedded in volumetric images, and thus "drilling" may be more efficient than "scanning."

Xiong W, Cepko C. Distinct Expression Patterns of AAV8 Vectors with Broadly Active Promoters from Subretinal Injections of Neonatal Mouse Eyes at Two Different Ages. Adv Exp Med Biol 2016;854:501-7.Abstract

The retinal expression patterns were analyzed following the injection of serotype 8 adeno-associated virus (AAV8) vectors that utilize two broadly active and commonly used sets of transcription regulatory sequences. These include the human cytomegalovirus (CMV) immediate early (IE) enhancer/promoter and the hybrid CAG element (also known as CAGGS or CBA) composed of a partial human CMV IE enhancer and the chicken β-actin promoter and intron. Subretinal delivery to postnatal day 0 (P0) or 6 (P6) mouse eyes resulted in efficient labeling of retinal cells, but with very distinct patterns. With P0 delivery, AAV8-CMV-GFP selectively labelled photoreceptors, while AAV8-CAG-GFP efficiently labeled both outer and inner retinal neurons, including photoreceptors, horizontal cells, amacrine cells and retinal ganglion cells. With P6 delivery, both vectors led to efficient labeling of photoreceptors and Müller glia cells, but not of inner retinal neurons. Our results suggest that the cell types that express the genes encoded by subretinally delivered AAV8 vectors are determined by both the timing of the injection and the regulatory sequences.