Progressive Age-Related Changes Similar to Age-Related Macular Degeneration in a Transgenic Mouse Model

Age-related macular degeneration (AMD) is the major cause of blindness in the developed world. its pathomechanism is unknown and its late onset, complex genetics and strong environmental components have all hampered investigations. Here we demonstrate the development of an animal model for AMD that reproduces features associated with geographic atrophy, a transgenic mouse line (mcd/mcd) expressing a mutated form of cathepsin D that is enzymatically inactive thus impairing processing of phagocytosed photoreceptor outer segments in the retinal pigment epithelial (RPE) cells. Pigmentary changes indicating RPE cell atrophy and a decreased response to flash electroretinograms were observed in 11- to 12-month-old mcd/mcd mice. Histological studies showed RPE cell proliferation, photoreceptor degeneration, shortening of photoreceptor outer segments, and accumulation of immunoreactive photoreceptor breakdown products in the RPE cells. An accelerated photoreceptor cell death was detected in 12-month-old mcd/mcd mice. Transmission electron microscopy demonstrated presence of basal laminar and linear deposits that are considered to be the hallmarks of AMD. Small hard drusen associated with human age-related maculopathy were absent in the mcd/mcd mouse model at the ages analyzed. in summary, this model presents several features of AMD, thus providing a valuable tool for investigating the underlying biological processes and pathomechanism of AMD.

Exploring motor neuron degeneration in ALS - prevention by glycoursodeoxycholic acid and signaling to microglia

Dissertação para obtenção do Grau de Mestre em Genética Molecular e Biomedicina

The Role of the Fbox Protein CG6758 in Xbp1s Induced Retinal Degeneration in Drosophila

The Unfolded Protein Response (UPR) is a signaling pathway that is activated by an accumulation of unfolded or misfolded proteins in the endoplasmic reticulum (ER) that causes ER stress. The activation of the UPR aims to restore ER homeostasis by attenuation of ER client protein translation, increased transcription of ER chaperones and ER associated degradation (ERAD) factors. If ER stress is too long or too strong, cells may die. The main signaling branch of the UPR is mediated by the ER transmembrane protein IRE1 and the transcription factor Xbp1. The active, spliced form of Xbp1 (Xbp1spliced) acts as a transcription factor with protective function against toxic protein aggregation. However, overexpression of Xbp1spliced in the developing Drosophila eye causes degeneration of the eye (“glossy” eye phenotype).(...)

Bacterial cellulose as a novel substrate for retinal pigment epithelium cells transplantation in age-related macular degeneration

Tese de Doutoramento em Engenharia Química e Biológica.

Mitral valve repair. Quadrangular resection of the posterior leaflet in patients with myxomatous degeneration

OBJECTIVE - To analyze the immediate and late results of mitral valve repair with quadrangular resection of the posterior leaflet without the use of a prosthetic ring annuloplasty. METHODS - Using this technique, 118 patients with mitral valve prolapse who underwent mitral repair from January '84 through December '96 were studied. Age ranged from 30 to 86 (mean = 59.1±11.8) years and 62.7% were males. An associated surgery was performed in 22% of the patients, and coronary artery bypass graft was the most frequently performed surgery (15 patients - 12.7%). In 20 (16.9%) patients other associated techniques of mitral valve repair were used and shortening of elongated chordae tendineae was the most frequent one (6 patients). RESULTS - Immediate mortality was 0.9% (one patient). Long-term rates for thromboembolism, endocarditis, re-operation and death in the late postoperative period were 0.4%, 0.4%, 1.7% and 2.2% patients/year, respectively. The actuarial curve of survival was 83.8±8.6% over 12 years; survival free from re-operation was 91.8±4.3%, free from endocarditis was 99.2±0.8% and free from thromboembolism was 99.2±0.8%. In the late postoperative period, 93.8% of the patients were in functional class 1 (NYHA), with a complete follow-up in 89.7% of the patients. CONCLUSION - Patients with mitral valve prolapse who undergo mitral valve repair using this technique have a satisfactory prognosis over 12 years.

Retinal pigment epithelium tears after intravitreal injection of ranibizumab for predominantly classic neovascular membranes secondary to age-related macular degeneration.

PURPOSE: Retinal pigment epithelium (RPE) tear is an extremely rare complication in patients with classic neovascular membranes without RPE detachment. We evaluate their incidence and functional outcome following treatment with intravitreal ranibizumab. METHODS: Observational study of 72 consecutive patients (74 eyes) treated at Jules Gonin University Eye Hospital, Lausanne, with intravitreal ranibizumab 0.5 mg for classic choroidal neovascularization (CNV) between March 2006 and February 2008. Best-corrected visual acuity (BCVA), fundus examination and optical coherence tomography were recorded monthly; fluorescein angiography was performed at baseline and repeated at least every 3 months. RESULTS: RPE tears occurred in four (5.4%) eyes temporal to the fovea, after a mean of four injections (range 3-6). Mean baseline BCVA was 0.25 decimal equivalent (logMAR 0.67) and improved despite the RPE tear to 0.6 decimal equivalent (logMAR 0.22). CONCLUSION: RPE tears following intravitreal ranibizumab injections for classic CNV can occur in about 5% of patients, even in the absence of baseline RPE detachment. Nevertheless, vision may improve provided the fovea is not involved.

NR2E3 mutations in enhanced S-cone sensitivity syndrome (ESCS), Goldmann-Favre syndrome (GFS), clumped pigmentary retinal degeneration (CPRD), and retinitis pigmentosa (RP).

NR2E3, also called photoreceptor-specific nuclear receptor (PNR), is a transcription factor of the nuclear hormone receptor superfamily whose expression is uniquely restricted to photoreceptors. There, its physiological activity is essential for proper rod and cone photoreceptor development and maintenance. Thirty-two different mutations in NR2E3 have been identified in either homozygous or compound heterozygous state in the recessively inherited enhanced S-cone sensitivity syndrome (ESCS), Goldmann-Favre syndrome (GFS), and clumped pigmentary retinal degeneration (CPRD). The clinical phenotype common to all these patients is night blindness, rudimental or absent rod function, and hyperfunction of the "blue" S-cones. A single p.G56R mutation is inherited in a dominant manner and causes retinitis pigmentosa (RP). We have established a new locus-specific database for NR2E3 (www.LOVD.nl/eye), containing all reported mutations, polymorphisms, and unclassified sequence variants, including novel ones. A high proportion of mutations are located in the evolutionarily-conserved DNA-binding domains (DBDs) and ligand-binding domains (LBDs) of NR2E3. Based on homology modeling of these NR2E3 domains, we propose a structural localization of mutated residues. The high variability of clinical phenotypes observed in patients affected by NR2E3-linked retinal degenerations may be caused by different disease mechanisms, including absence of DNA-binding, altered interactions with transcriptional coregulators, and differential activity of modifier genes.

Exome sequencing extends the phenotypic spectrum for ABHD12 mutations: from syndromic to nonsyndromic retinal degeneration.

OBJECTIVE: To identify the genetic causes underlying autosomal recessive retinitis pigmentosa (arRP) and to describe the associated phenotype. DESIGN: Case series. PARTICIPANTS: Three hundred forty-seven unrelated families affected by arRP and 33 unrelated families affected by retinitis pigmentosa (RP) plus noncongenital and progressive hearing loss, ataxia, or both, respectively. METHODS: A whole exome sequencing (WES) analysis was performed in 2 families segregating arRP. A mutational screening was performed in 378 additional unrelated families for the exon-intron boundaries of the ABHD12 gene. To establish a genotype-phenotype correlation, individuals who were homozygous or compound heterozygotes of mutations in ABHD12 underwent exhaustive clinical examinations by ophthalmologists, neurologists, and otologists. MAIN OUTCOME MEASURES: DNA sequence variants, best-corrected visual acuity, visual field assessments, electroretinogram responses, magnetic resonance imaging, and audiography. RESULTS: After a WES analysis, we identified 4 new mutations (p.Arg107Glufs*8, p.Trp159*, p.Arg186Pro, and p.Thr202Ile) in ABHD12 in 2 families (RP-1292 and W08-1833) previously diagnosed with nonsyndromic arRP, which cosegregated with the disease among the family members. Another homozygous mutation (p.His372Gln) was detected in 1 affected individual (RP-1487) from a cohort of 378 unrelated arRP and syndromic RP patients. After exhaustive clinical examinations by neurologists and otologists, the 4 affected members of the RP-1292 had no polyneuropathy or ataxia, and the sensorineural hearing loss and cataract were attributed to age or the normal course of the RP, whereas the affected members of the families W08-1833 and RP-1487 showed clearly symptoms associated with polyneuropathy, hearing loss, cerebellar ataxia, RP, and early-onset cataract (PHARC) syndrome. CONCLUSIONS: Null mutations in the ABHD12 gene lead to PHARC syndrome, a neurodegenerative disease including polyneuropathy, hearing loss, cerebellar ataxia, RP, and early-onset cataract. Our study allowed us to report 5 new mutations in ABHD12. This is the first time missense mutations have been described for this gene. Furthermore, these findings are expanding the spectrum of phenotypes associated with ABHD12 mutations ranging from PHARC syndrome to a nonsyndromic form of retinal degeneration.

Ultrastructure of the ovary of Dermatobia hominis (Diptera: Cuterebridae): III. Gonial cell degeneration

We studied the ultrastructural aspects of pre-pupae and pupae ovaries of Dermatobia hominis. Physiological degeneration of gonial cells was observed: (a) after the ovarioles differentiation, in the oogonia residing in the apical region of the ovary; (b) at the beginning of vitellogenesis, in the cystoblasts close to the terminal filament. The significance of gonial cell degeneration was correlated with the physiological changes wich occur in the ovary during development.

CCR2(+) monocytes infiltrate atrophic lesions in age-related macular disease and mediate photoreceptor degeneration in experimental subretinal inflammation in Cx3cr1 deficient mice.

Atrophic age-related macular degeneration (AMD) is associated with the subretinal accumulation of mononuclear phagocytes (MPs). Their role in promoting or inhibiting retinal degeneration is unknown. We here show that atrophic AMD is associated with increased intraocular CCL2 levels and subretinal CCR2(+) inflammatory monocyte infiltration in patients. Using age- and light-induced subretinal inflammation and photoreceptor degeneration in Cx3cr1 knockout mice, we show that subretinal Cx3cr1 deficient MPs overexpress CCL2 and that both the genetic deletion of CCL2 or CCR2 and the pharmacological inhibition of CCR2 prevent inflammatory monocyte recruitment, MP accumulation and photoreceptor degeneration in vivo. Our study shows that contrary to CCR2 and CCL2, CX3CR1 is constitutively expressed in the retina where it represses the expression of CCL2 and the recruitment of neurotoxic inflammatory CCR2(+) monocytes. CCL2/CCR2 inhibition might represent a powerful tool for controlling inflammation and neurodegeneration in AMD.

Intravitreal Ranibizumab in the Treatment of Predominantly Hemorrhagic Lesions in Exudative Age-Related Macular Degeneration.

BACKGROUND: Submacular hemorrhage is a manifestation of neovascular age-related macular degeneration (AMD) that has a very poor natural history leading to severe visual loss. We have evaluated the safety and efficacy of intravitreal ranibizumab in the treatment of predominantly hemorrhagic AMD. PATIENTS AND METHODS: A retrospective study of patients with predominantly hemorrhagic AMD treated with intravitreal ranibizumab at the Jules Gonin Eye Hospital between December 2006 and December 2008 was undertaken. Baseline and monthly follow-up exams included visual acuity (VA), fundus exam and optical coherence tomography (OCT) while fluorescein and indocyanine green angiography were performed at least every three months. RESULTS: The study included 8 eyes. The mean follow-up was 13 months (SD: 6.3). The mean number of intravitreal injections administered for each patient was 6.4 (SD: 2). 50 % of the patients demonstrated stable or improved VA. The size of hemorrhage at baseline was inversely correlated to the final VA (two-tailed p value = 0.038) and positively correlated to the final central macular thickness (two-tailed p value = 0.021). Anticoagulation treatment was inversely correlated to the time of hemorrhage resolution (two-tailed p value = 0.039). CONCLUSIONS: Intravitreal ranibizumab may be an effective treatment for predominantly hemorrhagic lesions due to neovascular AMD.

Neonatal hyperglycemia inhibits angiogenesis and induces inflammation and neuronal degeneration in the retina.

Recent evidence suggests that transient hyperglycemia in extremely low birth weight infants is strongly associated with the occurrence of retinopathy of prematurity (ROP). We propose a new model of Neonatal Hyperglycemia-induced Retinopathy (NHIR) that mimics many aspects of retinopathy of prematurity. Hyperglycemia was induced in newborn rat pups by injection of streptozocine (STZ) at post natal day one (P1). At various time points, animals were assessed for vascular abnormalities, neuronal cell death and accumulation and activation of microglial cells. We here report that streptozotocin induced a rapid and sustained increase of glycemia from P2/3 to P6 without affecting rat pups gain weight or necessitating insulin treatment. Retinal vascular area was significantly reduced in P6 hyperglycemic animals compared to control animals. Hyperglycemia was associated with (i) CCL2 chemokine induction at P6, (ii) a significant recruitment of inflammatory macrophages and an increase in total number of Iba+ macrophages/microglia cells in the inner nuclear layer (INL), and (iii) excessive apoptosis in the INL. NHIR thereby reproduces several aspects of ischemic retinopathies, including ROP and diabetic retinopathies, and might be a useful model to decipher hyperglycemia-induced cellular and molecular mechanisms in the small rodent.

Water-filtered infrared-A radiation (wIRA) is not implicated in cellular degeneration of human skin

Rapport de synthèse : Introduction : le vieillissement cutané est un processus biologique complexe auquel participe une exposition excessive au rayonnement ultraviolet du soleil. En particulier, les longueurs d'onde des rayons ultraviolets A et B (UV-A et UV-B) peuvent induire une augmentation de la synthèse de protéases, comme la métalloprotéinase matricielle 1 (MMP-1), qui est impliquée dans le processus de vieillissement. La thermothérapie par infrarouges, dont les longueurs d'onde sont plus longues que celles des UV, est largement utilisée à des fins thérapeutiques ou cosmétiques. Or, il a été démontré que les infrarouges en filtration aqueuse (IRFA) pouvaient induire une augmentation de la production de MMP-1 et par conséquent être nocifs. Il serait donc intéressant d'évaluer les effets des IRFA au niveau cellulaire et moléculaire. But Expérimental : étudier les effets des lampes à infrarouges en filtration aqueuse utilisées en clinique sur des fibroblastes cutanés humains en culture, afin d'analyser l'expression du gène codant pour la protéine MMP-1. Méthode : des fibroblastes cutanés humain ont été irradiés d'une part avec approximativement 88% d'IRFA (780-1400 nm) et 12% de lumière rouge (LR, 665-780 nm) avec 380 mW/cm2 IRFA(+LR) (333 mW/cm2 IRFA) et d'autre part avec des UV-A comme contrôle. Des courbes de survie cellulaire ont été établies après une exposition allant de 15 minutes à 8 heures au IRFA(+LR) (340-10880 J/cm2 wIRA(+RL), 300-9600 J/cm2 wIRA) ou de 15 à 45 minutes aux UV-A(+BL) (25-75 J/cm2 UV-A(+BL). L'induction de l'ARNm du gène de la MMP-1 a été analysé dans les fibroblastes cutanés humain à deux températures physiologiques (30°C et 37°C) lors d'expositions uniques de 15 à 60 minutes aux IRFA(+LR) (340-1360 J/cm2 IRFA(+LR), 300-1200 J/cm2 IRFA) ou de 30 minutes aux UV-A(+BL) (50 J/cm2 UVA(+BL)). De plus, nous avons effectué des irradiations répétées, une a chaque passage cellulaire jusqu'au passage. 10 de 15 minutes d'IRFA(+LR) 340 J/cm2 IRFA(+LR), 300 J/cm2 IRFA) . Résultats : une exposition unique aux UV-A (+BL) entraîne chez des fibroblastes cutanés humains une augmentation de la mort cellulaire, ainsi qu'une forte augmentation de l'expression du gène codant pour la MMP-1. L'augmentation mise en évidence pour cet ARNm varie en fonction de la technique utilisée : elle est de 11 ± 1 fois par RT-PCR classique, de 76 ± 2 fois par RT-PCR quantitative à 30°C, et de 75 ± 1 fois par RT-PCR quantitative à 37°C. Par contre, une exposition unique ou répétée aux IRFA (+LR) n'induit aucune augmentation de la mort cellulaire, ni de l'expression de l'ARNm de la MMP-1 chez ces fibroblastes. Conclusions : les résultats de cette étude montrent que, contrairement aux rayons ultraviolets, les IRFA (+LR) ne semblent impliqués ni dans le vieillissement, ni dans la mort cellulaire, même utilisés à des doses très élevées. Ces résultats sont en accord avec certaines investigations in vivo montrant une induction de MMP-1 par des UV et non des infrarouges. Ces dernières études suggèrent d'ailleurs plutôt un rôle protecteur des IRFA (+LR).

Evaluation des modifications anatomiques et fonctionnelles de la macula après chirurgie des membranes néovasculaires rétrofovéolaires dans la dégénérescence maculaire liée à l'âge [Evaluation of functional and anatomical changes in the macula after surgery for retro-foveal neovascularization of membranes in age-related macular degeneration].

PURPOSE: The aim of this study was to evaluate the direct effect of surgical treatment of subfoveolar neovascular membranes in age related macular degeneration to macular functions. PATIENTS AND METHODS: Thirteen eyes of 13 patients were included in this study. Macular function was assayed by visual acuity and central visual field using the Octopus perimeter before surgery and in the first three post operative months. Pre and post operative fluorescein angiography frames were digitalized and the size of each lesions were compared. RESULTS: After a 3 months follow up, visual acuity remained stable or improved in 66% of the patients. However, visual acuity was better than 0.1 in 15% of the patients. Central visual field comparison disclosed a significant worsening of the retinal sensitivity in the 3 degree field surrounding the central point. On fluorescein frames, submacular scar was 141% of the size of the neovascular membrane. After a mean follow up of 6.9 months (range 3-14), one case of recurrence occurred. A cataract was observed in 85% of the phakic patients followed for more than six months. CONCLUSION: After a short term follow up, surgery can stabilise visual acuity, even though it remains poor. A worsening of the scotoma in the 3 degrees surrounding the central point is observed. However, patients noticed a subjective visual improvement in 62% of the case.