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BACKGROUND: Inherited retinal degeneration (IRD) associated with mutations in the Crumbs homolog 1 (CRB1) gene is associated with a severe, early-onset retinal degeneration for which no therapy currently exists. Base editing, with its capability to precisely catalyse permanent nucleobase conversion in a programmable manner, represents a novel therapeutic approach to targeting this autosomal recessive IRD, for which a gene supplementation is challenging due to the need to target three different retinal CRB1 isoforms. PURPOSE: To report and classify a novel CRB1 variant and envision a possible therapeutic approach in form of base editing. METHODS: Case report. RESULTS: A 16-year-old male patient with a clinical diagnosis of early-onset retinitis pigmentosa (RP) and characteristic clinical findings of retinal thickening and coarse lamination was seen at the Oxford Eye Hospital. He was found to be compound heterozygous for two CRB1 variants: a novel pathogenic nonsense variant in exon 9, c.2885T>A (p.Leu962Ter), and a likely pathogenic missense change in exon 6, c.2056C>T (p.Arg686Cys). While a base editing strategy for c.2885T>A would encompass a CRISPR-pass mediated "read-through" of the premature stop codon, the resulting missense changes were predicted to be "possibly damaging" in in-silico analysis. On the other hand, the transversion missense change, c.2056C>T, is amenable to transition editing with an adenine base editor (ABE) fused to a SaCas9-KKH with a negligible chance of bystander edits due to an absence of additional Adenines (As) in the editing window. CONCLUSIONS: This case report records a novel pathogenic nonsense variant in CRB1 and gives an example of thinking about a base editing strategy for a patient compound heterozygous for CRB1 variants.
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Proteínas del Ojo , Degeneración Retiniana , Adenina , Adolescente , Secuencia de Aminoácidos , Sistemas CRISPR-Cas , Codón sin Sentido , Proteínas del Ojo/genética , Humanos , Masculino , Proteínas de la Membrana/genética , Mutación , Proteínas del Tejido Nervioso/genética , Nucleótidos , Degeneración Retiniana/genéticaRESUMEN
BACKGROUND: The retinol binding protein 4 (RBP4) is essential in delivering retinol to the retinal pigment epithelium and normal functioning of the visual cycle. Homozygous mutations in the RBP4 gene lead to severe retinitis pigmentosa that is phenotypically indistinguishable from retinitis pigmentosa caused by other recessive mutations. METHODS: Case Report. PURPOSE: To report a novel homozygous RBP4 c.67 C > T variant in a case of retinitis pigmentosa associated with severe childhood acne vulgaris. RESULTS: A 49-year old Caucasian man with a family history of retinitis pigmentosa, presented with low vision and night blindness from early childhood. Fundus examination showed findings typical of recessive retinitis pigmentosa. Next generation sequencing analysis revealed a novel homozygous RBP4 c.67 C > T variant. Examination of patient's back showed widespread scaring and hyperpigmentation secondary to severe childhood-onset acne vulgaris. Patient's affected brother, positive for the same homozygous variant, also had a history of severe acne vulgaris whereas the unaffected brother did not, confirming that mutations in RBP4 segregated with the acne vulgaris phenotype in this family. CONCLUSIONS: We describe a case of retinitis pigmentosa associated with acne vulgaris and highlight the role of this systemic manifestation of retinol deficiency in confirming pathogenicity of the novel variant. Given the small size of the genomic RBP4 DNA (0.6kb), gene therapy using an adeno-associated viral vector with subretinal delivery has great potential to treat this severe childhood-onset blinding retinal disease. In addition, ubiquitous expression of RBP4 supports the development of in vitro functional assays to test the vector potency for clinical use.
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Acné Vulgar/patología , Homocigoto , Mutación , Retinitis Pigmentosa/patología , Proteínas Plasmáticas de Unión al Retinol/genética , Acné Vulgar/complicaciones , Acné Vulgar/genética , Femenino , Genes Recesivos , Humanos , Masculino , Persona de Mediana Edad , Linaje , Fenotipo , Retinitis Pigmentosa/complicaciones , Retinitis Pigmentosa/genéticaRESUMEN
Essentials Critically ill cancer patients require pharmacologic prophylaxis for venous thromboembolism (VTE). Patients from 566 hospitals in the United States between 2010 and 2014 were included. Low-molecular-weight heparin (LMWH) prophylaxis was not associated in a reduction of VTE rates. LMWH prophylaxis was associated with a reduction in bleeding and heparin induced thrombocytopenia. SUMMARY: Background Critically ill patients with cancer are at increased risk of venous thromboembolism (VTE) from physical and cellular factors, requiring pharmacologic prophylaxis to reduce the risk of VTE. Objectives To assess whether low-molecular-weight heparin (LMWH) prophylaxis reduces in-hospital rates of VTE or improves clinical outcomes compared with unfractionated heparin (UFH) prophylaxis in critically ill patients with cancer. Methods We used a propensity-matched comparative-effectiveness cohort from the Premier Database. Patients aged 18 years or older with a primary diagnosis of cancer, intensive care unit admission and VTE prophylaxis within 2 days of admission between 1 January 2010 and 31 December 2014 were included. Patients were divided into LMWH or UFH prophylaxis groups. Results A total of 103 798 patients were included; 75 321 (72.6%) patients received LMWH and 28 477 (27.4%) patients received UFH. Propensity analysis matched (2 : 1) 42 343 LMWH patients and 21 218 UFH patients. Overall, LMWH was not associated with a decreased incidence of VTE (5.32% vs. 5.50%). LMWH prophylaxis was associated with a reduction in pulmonary embolism (0.70% vs. 0.99%), significant bleeding (13.3% vs. 14.8%) and heparin-induced thrombocytopenia (HIT) (0.06% vs. 0.19%). In non-metastatic solid disease, LMWH was associated with decreased VTE (4.27% vs. 4.84%) and PE (0.47% vs. 0.95%). Conclusions The use of an LMWH for VTE prophylaxis was not associated with a reduction in the incidence of in-hospital VTE as compared with UFH, but was associated with significant reductions in PE, clinically important bleeding events, and incidence of HIT in critically ill patients with cancer.
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Anticoagulantes/uso terapéutico , Inhibidores del Factor Xa/uso terapéutico , Fondaparinux/uso terapéutico , Heparina de Bajo-Peso-Molecular/uso terapéutico , Neoplasias/tratamiento farmacológico , Tromboembolia Venosa/prevención & control , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Anticoagulantes/efectos adversos , Investigación sobre la Eficacia Comparativa , Enfermedad Crítica , Bases de Datos Factuales , Inhibidores del Factor Xa/efectos adversos , Femenino , Fondaparinux/efectos adversos , Hemorragia/inducido químicamente , Heparina de Bajo-Peso-Molecular/efectos adversos , Humanos , Masculino , Persona de Mediana Edad , Neoplasias/sangre , Neoplasias/complicaciones , Factores de Riesgo , Trombocitopenia/inducido químicamente , Factores de Tiempo , Resultado del Tratamiento , Estados Unidos , Tromboembolia Venosa/sangre , Tromboembolia Venosa/etiología , Adulto JovenRESUMEN
Microsurgery of the retina would be dramatically improved by instruments that offer supra-human precision. Here, we report the results of a first-in-human study of remotely controlled robot-assisted retinal surgery performed through a telemanipulation device. Specifically, 12 patients requiring dissection of the epiretinal or inner limiting membrane over the macula were randomly assigned to either undergo robot-assisted-surgery or manual surgery, under general anaesthesia. We evaluated surgical success, duration of surgery and amount of retinal microtrauma as a proxy for safety. Surgical outcomes were equally successful in the robotic-surgery and manual-surgery groups. Differences in the amount of retinal microtrauma between the two groups were statistically insignificant, yet dissection took longer with robotic surgery (median time, 4 min 5 s) than with manual surgery (1 min 20 s). We also show the feasibility of using the robot to inject recombinant tissue plasminogen activator under the retina to displace sight-threatening haemorrhage in three patients under local anaesthesia. A safe and viable robotic system for intraocular surgery would enable precise and minimally traumatic delivery of gene therapy or cell therapy to the retina.
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Inherited retinal diseases are thought to be the leading cause of sight loss in the working age population. Mutations found in the RPGR and CHM genes cause retinitis pigmentosa (RP) and choroideremia, respectively. In the first instance, an X-linked family history of visual field loss commonly raises the suspicion of one of these two genes. In choroideremia, the classic description of a white fundal reflex secondary to the widespread chorioretinal degeneration was made over a hundred years ago in Caucasians. But, it is not so obvious in heavily pigmented fundi. Hence, the clinical diagnosis of CHM in non-Caucasian patients may be challenging in the first stages of the disease. Here we report a case of a Southeast Asian gentleman who has a family history of X-linked retinal degeneration and was found to have a confirmed in-frame deletion of 12 DNA nucleotides in exon 15 of the RPGR gene. Later in life, however, his fundal appearance showed unusual areas of circular pigment hypertrophy and clumping. He was therefore tested for carrying a disease-causing mutation in the CHM gene and a null mutation was found. Since gene therapy trials are ongoing for both of these conditions, it has now become critically important to establish the correct genetic diagnosis in order to recruit suitable candidates. Moreover, this case demonstrates the necessity to remain vigilant in the interpretation of genetic results which are inconsistent with clinical features.
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Coroideremia/diagnóstico , Errores Diagnósticos , Proteínas del Ojo/genética , Fondo de Ojo , Genes Ligados a X , Retinitis Pigmentosa/diagnóstico , Adulto , Coroideremia/complicaciones , Coroideremia/genética , Humanos , Masculino , Mutación , Retinitis Pigmentosa/complicaciones , Retinitis Pigmentosa/genéticaRESUMEN
The importance of establishing a genetic diagnosis in patients with a choroideremia phenotype has been underscored by the advent of gene replacement therapy for this condition. Here, we describe a complex imbalance at the CHM locus in a male patient with classical disease. At the DNA level, this imbalance consists of 2 non-contiguous duplications (exons 1-2 and 9-12). Further characterization suggests the generation of 2 independent CHM transcriptional units, one of which may produce a deleted form of the Rab escort protein 1 protein. Expression of such a type of aberrant protein in photoreceptors may have important implications when considering gene therapy for this disorder.
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Proteínas Adaptadoras Transductoras de Señales/genética , Coroideremia/genética , Exones/genética , Duplicación de Gen , Adulto , Coroideremia/diagnóstico , Coroideremia/fisiopatología , Humanos , Masculino , Reacción en Cadena de la Polimerasa Multiplex , Tomografía de Coherencia Óptica , Agudeza VisualRESUMEN
There is much debate on the adeno-associated virus (AAV) serotype that best targets specific retinal cell types and the route of surgical delivery-intravitreal or subretinal. This study compared three of the most efficacious AAV vectors known to date in a mouse model of retinal degeneration (rd1 mouse) and macaque and human retinal explants. Green fluorescent protein (GFP) driven by a ubiquitous promoter was packaged into three AAV capsids: AAV2/8(Y733F), AAV2/2(quad Y-F) and AAV2/2(7m8). Overall, AAV2/2(7m8) transduced the largest area of retina and resulted in the highest level of GFP expression, followed by AAV2/2(quad Y-F) and AAV2/8(Y733F). AAV2/2(7m8) and AAV2/2(quad Y-F) both resulted in similar patterns of transduction whether they were injected intravitreally or subretinally. AAV2/8(Y733F) transduced a significantly smaller area of retina when injected intravitreally compared with subretinally. Retinal ganglion cells, horizontal cells and retinal pigment epithelium expressed relatively high levels of GFP in the mouse retina, whereas amacrine cells expressed low levels of GFP and bipolar cells were infrequently transduced. Cone cells were the most frequently transduced cell type in macaque retina explants, whereas Müller cells were the predominant transduced cell type in human retinal explants. Of the AAV serotypes tested, AAV2/2(7m8) was the most effective at transducing a range of cell types in degenerate mouse retina and macaque and human retinal explants.
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Dependovirus/genética , Recombinación Genética , Retina/metabolismo , Tropismo Viral/genética , Animales , Modelos Animales de Enfermedad , Vectores Genéticos , Humanos , Inyecciones Intravítreas , Macaca , Ratones , Regiones Promotoras Genéticas , Retina/citología , Retina/virología , Degeneración Retiniana/genética , Células Ganglionares de la Retina/metabolismo , Epitelio Pigmentado de la Retina/metabolismo , Ensamble de VirusRESUMEN
PurposeSafe and reproducible delivery of gene therapy vector into the subretinal space is essential for successful targeting of the retinal pigment epithelium (RPE) and photoreceptors. The success of surgery is critical for the clinical efficacy of retinal gene therapy. Iatrogenic detachment of the degenerate (often adherent) retina in patients with hereditary retinal degenerations and small volume (eg, 0.1 ml) subretinal injections pose new surgical challenges.MethodsOur subretinal gene therapy technique involved pre-operative planning with optical coherence tomography (OCT) and autofluorescence (AF) imaging, 23 G pars plana vitrectomy, internal limiting membrane staining with Membrane Blue Dual (DORC BV, Zuidland, Netherlands), a two-step subretinal injection using a 41 G Teflon tipped cannula (DORC) first with normal saline to create a parafoveal bleb followed by slow infusion of viral vector via the same self-sealing retinotomy. Surgical precision was further enhanced by intraoperative OCT (Zeiss Rescan 7000, Carl Zeiss Meditec AG, Jena, Germany). Foveal functional and structural recovery was evaluated using best-corrected Early Treatment Diabetic Retinopathy Study (ETDRS) visual acuity, microperimetry and OCT.ResultsTwo patients with choroideremia aged 29 (P1) and 27 (P2) years, who had normal and symmetrical levels of best-corrected visual acuity (BCVA) in both eyes, underwent unilateral gene therapy with the fellow eye acting as internal control. The surgeries were uncomplicated in both cases with successful detachment of the macula by subretinal vector injection. Both treated eyes showed recovery of BCVA (P1: 76-77 letters; P2: 84-88 letters) and mean threshold sensitivity of the central macula (P1: 10.7-10.7 dB; P2: 14.2-14.1 dB) to baseline within a month. This was accompanied by normalisation of central retinal thickness on OCT.ConclusionsHerein we describe a reliable technique for subretinal gene therapy, which is currently used in clinical trials to treat choroideremia using an adeno-associated viral (AAV) vector encoding the CHM gene. Strategies to minimise potential complications, such as avoidance of excessive retinal stretch, air bubbles within the injection system, reflux of viral vector and post-operative vitritis are discussed.
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Proteínas Adaptadoras Transductoras de Señales/genética , Coroideremia/terapia , Dependovirus/genética , Técnicas de Transferencia de Gen , Terapia Genética/métodos , Vectores Genéticos , Adulto , Coroideremia/fisiopatología , Humanos , Inyecciones Intraoculares , Masculino , Retina/fisiología , Hermanos , Tomografía de Coherencia Óptica , Agudeza Visual , Pruebas del Campo Visual , VitrectomíaRESUMEN
Blindness due to outer retinal degeneration still remains largely untreatable. Photoreceptor loss removes light sensitivity, but the remaining inner retinal layers, the optic nerve, and indeed the physical structure of the eye itself may be unaffected by the degenerative processes. This provides the opportunity to restore some degree of vision with an electronic device in the subretinal space. In this lecture I will provide an overview of our experiences with the first-generation retinal implant Alpha IMS, developed by Retina Implant AG and based on the technology developed by Eberhart Zrenner as part of a multicentre clinical trial (NCT01024803). We are currently in the process of running a second NIHR-funded clinical trial to assess the next-generation device. The positive results from both studies to date indicate that the retinal implant should be included as a potential treatment for patients who are completely blind from retinitis pigmentosa. Evolution of the technology in future may provide further opportunities for earlier intervention or for other diseases.
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Ceguera/rehabilitación , Electrodos Implantados , Degeneración Retiniana/complicaciones , Percepción Visual/fisiología , Prótesis Visuales , Actividades Cotidianas , Ceguera/etiología , Ceguera/fisiopatología , Humanos , Retina/cirugía , Degeneración Retiniana/fisiopatología , Degeneración Retiniana/cirugía , Agudeza VisualRESUMEN
PurposeTo present a case series of cataract surgery outcomes in choroideremia eyes with an emphasis on the safety of this common operation in advanced stages of the disease.MethodsA single centre retrospective interventional case series comprising six patients with varying degrees of visual loss secondary to choroideremia underwent cataract surgery at a single tertiary eye hospital. Pre- and post-operative best-corrected Snellen visual acuity, spectral domain optical coherence tomography (SD-OCT), and slit lamp examination were performed together with fundus autofluorescence (FAF) and colour fundus photographs.The prevalence of intra- or post-operative complications, post-operative visual outcome, and change in central macular thickness were recorded.ResultsThe pre-operative best-corrected Snellen visual acuity in the operated eyes ranged from 6/12 (20/40) to PL. All but one patient had either an objective or a subjective improvement in visual acuity. There was no evidence of retinal phototoxicity or post-operative cystoid macular oedema (CMO). Three patients developed early capsular fibrosis.ConclusionsAlthough the residual functioning retina in choroideremia patients may be potentially vulnerable, this report finds no evidence of iatrogenic vision loss after uncomplicated cataract surgery. This suggests that cataract surgery may be performed safely in choroideremia patients, although a guarded prognosis for visual improvement should be emphasized in the informed consent.
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Extracción de Catarata , Coroideremia/cirugía , Anciano , Extracción de Catarata/normas , Coroideremia/patología , Femenino , Angiografía con Fluoresceína , Humanos , Edema Macular/etiología , Masculino , Persona de Mediana Edad , Complicaciones Posoperatorias , Estudios Retrospectivos , Tomografía de Coherencia Óptica , Agudeza VisualRESUMEN
WHAT IS KNOWN AND OBJECTIVE: Practices vary between institutions and amongst prescribers regarding when to initiate stress ulcer prophylaxis (SUP), which agent to choose (including doses and frequencies) and rationale, and decisions about escalation or discontinuation of therapy. The purpose of this survey is to evaluate the perceptions of prescribers about risk assessment of stress-related mucosal bleeding (SRMB) and practice patterns of SUP. METHODS: A cross-sectional survey of 800 US critical care prescribers using the membership of the Society of Critical Care Medicine. The levels of agreement with specific statements were rated on a nine-point Likert scale. RESULTS: Of 712 eligible recipients, 245 (34·4%) completed the questionnaire. Respondents were primarily attending physicians (81·2%) working in adult medical or surgical (59·2%) intensive care units. Mucosal ischaemia was identified as the pathophysiological cause of SRMB by 110 (44·9%) respondents. Respondents agreed that risk factors for SRMB were acute hepatic failure, anticoagulant use, burns >35%, coagulopathy, absence of enteral feeding, recent gastroduodenal ulcer, corticosteroid use, Helicobacter pylori infection, neurologic injury, trauma, NSAID use, mechanical ventilation, shock and sepsis. Histamine subtype 2 receptor antagonists (58·4%) and proton pump inhibitors (39·6%) were the most frequently chosen agents. No consensus was reached about whether either class is associated with clostridium difficile infection or nosocomial pneumonia. Reasons to discontinue therapy included clinically improved patient status (73·1%), extubation (68·2%), reversal of 'nil-by-mouth' (68·6%) and transfer to a non-ICU setting (67·8%). WHAT IS NEW AND CONCLUSIONS: Considerable variability exists in the perceptions surrounding risk factors for SRMB and prescribing patterns for SUP therapy likely because limited or conflicting data are available addressing these issues. Opportunities exist to educate prescribers and conduct research about the pathologic cause and risk factors for SRMB, the preferred class of agents, and the appropriate discontinuation of therapy.
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Antiulcerosos/uso terapéutico , Hemorragia Gastrointestinal/prevención & control , Úlcera Péptica/prevención & control , Pautas de la Práctica en Medicina/estadística & datos numéricos , Antiulcerosos/administración & dosificación , Actitud del Personal de Salud , Cuidados Críticos/métodos , Estudios Transversales , Hemorragia Gastrointestinal/etiología , Encuestas de Atención de la Salud , Humanos , Unidades de Cuidados Intensivos , Úlcera Péptica/etiología , Medición de Riesgo , Factores de Riesgo , Estrés Fisiológico , Encuestas y Cuestionarios , Factores de Tiempo , Estados UnidosRESUMEN
Female preference for male fin enhancements in poeciliid fishes may be driven by a preexisting perceptual bias for increased male lateral projection area (LPA). This hypothesis suggests that a male with enlarged body and/or fin size projects a larger image onto the female's retina at a given viewing distance, eliciting a greater sensory and thus behavioral response out of the female than a smaller male. Given the shared sensory/neural systems of opposite sex conspecifics, we might expect the LPA bias to also be present in males of at least some poeciliid species. However, we need not expect congruence between the sexes in the state of the bias over evolutionary time. To examine whether the sexes share a bias for sailfin-like dorsal fins, a trait not present in their evolutionary history, the bias favoring increased dorsal fin size and LPA observed in female Xiphophorus variatus, among other poeciliids, was investigated by testing male preference for dummy females varying in dorsal fin size, body size, and dorsal fin:body size ratio. In three sets of simultaneous choice experiments, males preferred females of larger body size when fin size was held constant and when total LPA was held constant, but showed no preference for larger fins when body size was held constant. The LPA bias is therefore less permissive in males than females with selection favoring a male's ability to discriminate between female body size - an indicator of fertility/fecundity - and fin size, which offers no known fitness benefits.
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Aletas de Animales/anatomía & histología , Preferencia en el Apareamiento Animal/fisiología , Poecilia/fisiología , Animales , Evolución Biológica , Tamaño Corporal , Femenino , Masculino , Tamaño de los Órganos , Factores Sexuales , Percepción Visual/fisiologíaAsunto(s)
Anticuerpos Monoclonales Humanizados/administración & dosificación , Neovascularización Coroidal/etiología , Degeneración Macular/complicaciones , Distrofia Miotónica/complicaciones , Factor A de Crecimiento Endotelial Vascular/antagonistas & inhibidores , Inhibidores de la Angiogénesis/administración & dosificación , Bevacizumab , Neovascularización Coroidal/diagnóstico , Neovascularización Coroidal/tratamiento farmacológico , Angiografía con Fluoresceína , Estudios de Seguimiento , Fondo de Ojo , Humanos , Inyecciones Intravítreas , Degeneración Macular/diagnóstico , Masculino , Distrofia Miotónica/diagnóstico , Adulto JovenRESUMEN
Degeneration of the neural retina is the leading cause of untreatable blindness in the developed world. Stem cell replacement therapy offers a novel strategy for retinal repair. Postmitotic photoreceptor precursors derived from the early postnatal (P) retina are able to migrate and integrate into the adult mouse retina following transplantation into the subretinal space, but it is likely that a large number of these cells would be required to restore vision. The adult recipient retina presents a very different environment to that from which photoreceptor precursor donor cells isolated from the developing postnatal retina are derived. Here we considered the possibility that modulation of the recipient environment by ectopic expression of developmentally regulated growth factors, normally present during photoreceptor development, might enhance the migration and integration of transplanted cells into the adult neural retina. Adeno-associated viral (AAV) vectors were used to introduce three growth factors previously reported to play a role in photoreceptor development, IGF1, FGF2, and CNTF, into the adult retina, prior to transplantation of P4 cells derived from the Nrl.GFP(+ve) neural retina. At 3 weeks posttransplantation the number of integrated, differentiated photoreceptor cells present in AAV-mediated neurotrophic factor-treated eyes was assessed and compared to control treated contralateral eyes. We show, firstly, that it is possible to manipulate the recipient retinal microenvironment via rAAV-mediated gene transfer with respect to these developmentally relevant growth factors. Moreover, when combined with cell transplantation, AAV-mediated expression of IGF1 led to significantly increased levels of cell integration, while overexpression of FGF2 had no significant effect on integrated cell number. Conversely, expression of CNTF led to a significant decrease in cell integration and an exacerbated glial response that led to glial scarring. Together, these findings demonstrate the importance of the extrinsic environment of the recipient retina for photoreceptor cell transplantation and show for the first time that it is possible to manipulate this environment using viral vectors to influence photoreceptor transplantation efficiency.
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Células Fotorreceptoras de Vertebrados/citología , Retina/citología , Animales , Diferenciación Celular , Supervivencia Celular , Factor Neurotrófico Ciliar/genética , Factor Neurotrófico Ciliar/metabolismo , Dependovirus/genética , Factor 2 de Crecimiento de Fibroblastos/genética , Factor 2 de Crecimiento de Fibroblastos/metabolismo , Terapia Genética , Vectores Genéticos/genética , Vectores Genéticos/metabolismo , Factor I del Crecimiento Similar a la Insulina/genética , Factor I del Crecimiento Similar a la Insulina/metabolismo , Ratones , Ratones Endogámicos C57BL , Células Fotorreceptoras de Vertebrados/trasplante , Retina/patología , Retina/ultraestructura , Degeneración Retiniana/patología , Degeneración Retiniana/terapiaRESUMEN
Genetic mutations are the cause of inherited retinal dystrophies. The underlying genetic basis of these diseases suggests that a gene therapy approach is logical either to replace or reduce the expression of defective genes. The first proof-of-concept clinical studies in patients with Leber's congenital amaurosis have suggested that retinal gene therapy is safe and potentially effective, at least for specific disease entities. In contrast to pharmacological treatment gene therapy has the advantage of being able to express a protein within specific cell populations and is a potentially definitive therapy. Besides replacing deficient genes in inherited diseases, additional strategies that might broaden the application of retinal gene therapy are also being developed. These include the permanent expression of neuroprotective substances or photosensitive molecules (so-called optogenetics). This overview discusses the current clinical strategies and potential problems of retinal gene therapy.
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Terapia Genética/métodos , Terapia Genética/tendencias , Distrofias Retinianas/genética , Distrofias Retinianas/terapia , Humanos , Resultado del TratamientoRESUMEN
OBJECTIVE: This was a pilot randomised controlled trial (RCT) to investigate the effect of post-operative face-down positioning on the outcome of macular hole surgery and to inform the design of a larger definitive study. METHODS: In all, 30 phakic eyes of 30 subjects with idiopathic full-thickness macular holes underwent vitrectomy with dye-assisted peeling of the ILM and 14% perfluoropropane gas. Subjects were randomly allocated to posture face down for 10 days (posturing group) or to avoid a face-up position only (non-posturing group). The primary outcome was anatomical hole closure. RESULTS: Macular holes closed in 14 of 15 eyes (93.3%; 95% confidence interval (CI) 68-100%) in the posturing group and in 9 of 15 (60%; 95% CI 32-84%) in the non-posturing group. In a subgroup analysis of outcome according to macular hole size, all holes smaller than 400 µm closed regardless of posturing (100%). In contrast, holes larger than 400 µm closed in 10 of 11 eyes (91%; 95% CI 58-99%) in the posturing group and in only 4 of 10 eyes (40%; 95% CI 12-74%) in the non-posturing group (Fisher's exact test P=0.02). CONCLUSION: Post-operative face-down positioning may improve the likelihood of macular hole closure, particularly for holes larger than 400 µm. These results support the case for a RCT.
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Posición Prona , Perforaciones de la Retina/cirugía , Vitrectomía/métodos , Anciano , Femenino , Fluorocarburos/administración & dosificación , Humanos , Londres , Masculino , Persona de Mediana Edad , Proyectos Piloto , Cuidados Posoperatorios/métodos , Agudeza VisualRESUMEN
Female preference for male fin elaborations in Poeciliid fishes may be driven by a sensory bias for increased lateral projection area (LPA) that has existed since the lineages diverged from a common ancestor. Previous research supports this hypothesis demonstrating female Poecilia latipinna, Poecilia mexicana, and Poecilia reticulata prefer males of larger body and dorsal fin size, but exhibit no such preferences when controlling for total LPA. In the current study, we further tested this hypothesis by presenting female platys, Xiphophorus variatus, with pairs of dummy males differing in: (1) body size (holding dorsal fin size constant); (2) dorsal fin size (holding body size constant); and (3) dorsal fin: body size ratio (holding total LPA constant). Females spent more time near dummies of greater body and dorsal fin size; however, in the third experiment, neither fin size, body size, nor any particular dorsal fin+body size combination was preferred. These results provide additional support for the LPA and sensory bias hypotheses, demonstrating that female X. variatus not only prefer males with "swords", but sailfin-like dorsal fins as well when body size is held constant. Shared preference for increased LPA is consistent with common ancestry of the sensory/neural systems in females of all four species.
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Aletas de Animales , Tamaño Corporal , Conducta de Elección , Ciprinodontiformes , Factores Sexuales , Animales , Femenino , Masculino , Tamaño de los ÓrganosRESUMEN
Stem cells, with their capacity to regenerate and replace diseased tissues, have recently been proposed as having great potential in the treatment of age-related macular degeneration (AMD). A stem cell therapeutic approach could operate to replace either the retinal pigment epithelium (RPE), the neurosensory retina or a combination of both. From the scientific perspective, RPE replacement alone is likely to be far more straightforward than rebuilding the complex circuitry of the neurosensory retina. Furthermore, recent advances with induced pluripotent stem cells have raised the real possibility of transplanting healthy 'young' autologous RPE into patients with early signs of AMD. At this stage, however, it is useful to reconsider some of the earlier clinical studies that used suspensions of autologous RPE cells harvested from the peripheral retina. These showed that isolated RPE cell suspensions had little capacity to recreate a monolayer on the diseased Bruch's membrane of AMD. To counter this problem, researchers from Southampton in the UK report the use of a synthetic polymer alternative to Bruch's membrane, which could provide a scaffold for future RPE derived from stem cells or possibly reopen opportunities for autologous RPE cells harvested from the peripheral retina.
Asunto(s)
Lámina Basal de la Coroides/trasplante , Degeneración Macular/cirugía , Epitelio Pigmentado de la Retina/trasplante , Animales , Lámina Basal de la Coroides/fisiología , Reprogramación Celular/fisiología , Humanos , Degeneración Macular/fisiopatología , Polímeros/uso terapéutico , Conejos , Epitelio Pigmentado de la Retina/fisiología , Trasplante de Células Madre , Inmunología del Trasplante , Trasplante AutólogoRESUMEN
Diseases culminating in photoreceptor loss are a major cause of untreatable blindness. Transplantation of rod photoreceptors is feasible, provided donor cells are at an appropriate stage of development when transplanted. Nevertheless, the proportion of cells that integrate into the recipient outer nuclear layer (ONL) is low. The outer limiting membrane (OLM), formed by adherens junctions between Müller glia and photoreceptors, may impede transplanted cells from migrating into the recipient ONL. Adaptor proteins such as Crumbs homologue 1 (Crb1) and zona occludins (ZO-1) are essential for localization of the OLM adherens junctions. We investigated whether targeted disruption of these proteins enhances donor cell integration. Transplantation of rod precursors in wild-type mice achieved 949 +/- 141 integrated cells. By contrast, integration is significantly higher when rod precursors are transplanted into Crb1(rd8/rd8) mice, a model of retinitis pigmentosa and Lebers congenital amaurosis that lacks functional CRB1 protein and displays disruption of the OLM (7,819 +/- 1,297; maximum 15,721 cells). We next used small interfering (si)RNA to transiently reduce the expression of ZO-1 and generate a reversible disruption of the OLM. ZO-1 knockdown resulted in similar, significantly improved, integration of transplanted cells in wild-type mice (7,037 +/- 1,293; maximum 11,965 cells). Finally, as the OLM remains largely intact in many retinal disorders, we tested whether transient ZO-1 knockdown increased integration in a model of retinitis pigmentosa, the rho(-/-) mouse; donor cell integration was significantly increased from 313 +/- 58 cells without treatment to 919 +/- 198 cells after ZO-1 knockdown. This study shows that targeted disruption of OLM junctional proteins enhances integration in the wild-type and degenerating retina and may be a useful approach for developing photoreceptor transplantation strategies.
Asunto(s)
Proteínas de la Membrana/antagonistas & inhibidores , Proteínas del Tejido Nervioso/genética , Fosfoproteínas/antagonistas & inhibidores , Células Fotorreceptoras Retinianas Bastones/trasplante , Retinitis Pigmentosa/terapia , Trasplante de Células Madre , Animales , Movimiento Celular , Proteínas de la Membrana/genética , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Fosfoproteínas/genética , Interferencia de ARN , ARN Interferente Pequeño/metabolismo , Retinitis Pigmentosa/metabolismo , Proteína de la Zonula Occludens-1 , Quinasas Asociadas a rho/deficiencia , Quinasas Asociadas a rho/genética , Quinasas Asociadas a rho/metabolismoRESUMEN
Cell transplantation is a novel therapeutic strategy to restore visual responses to the degenerate adult neural retina and represents an exciting area of regenerative neurotherapy. So far, it has been shown that transplanted postmitotic photoreceptor precursors are able to functionally integrate into the adult mouse neural retina. In this review, we discuss the differentiation of photoreceptor cells from both adult and embryonic-derived stem cells and their potential for retinal cell transplantation. We also discuss the strategies used to overcome barriers present in the degenerate neural retina and improve retinal cell integration. Finally, we consider the future translation of retinal cell therapy as a therapeutic strategy to treat retinal degeneration.