AIM:To investigate the stability of the seven housekeeping genes:beta-actin(ActB),glyceraldehyde-3-phosphate dehydrogenase(GAPDH),18s ribosomal unit 5(18s),cyclophilin A(CycA),hypoxanthine-guanine phosphoribosyl trans...AIM:To investigate the stability of the seven housekeeping genes:beta-actin(ActB),glyceraldehyde-3-phosphate dehydrogenase(GAPDH),18s ribosomal unit 5(18s),cyclophilin A(CycA),hypoxanthine-guanine phosphoribosyl transferase(HPRT),ribosomal protein large P0(36B4)and terminal uridylyl transferase 1(U6)in the diabetic retinal tissue of rat model.METHODS:The expression of these seven genes in rat retinal tissues was determined using real-time quantitative reverse transcription polymerase chain reaction(RT-qPCR)in two groups;normal control rats and streptozotocininduced diabetic rats.The stability analysis of gene expression was investigated using geNorm,NormFinder,BestKeeper,and comparative delta-Ct(ΔCt)algorithms.RESULTS:The 36B4 gene was stably expressed in the retinal tissues of normal control animals;however,it was less stable in diabetic retinas.The 18s gene was expressed consistently in both normal control and diabetic rats’retinal tissue.That this gene was the best reference for data normalisation in RT-qPCR studies that used the retinal tissue of streptozotocin-induced diabetic rats.Furthermore,there was no ideal gene stably expressed for use in all experimental settings.CONCLUSION:Identifying relevant genes is a need for achieving RT-qPCR validity and reliability and must be appropriately achieved based on a specific experimental setting.展开更多
Background:It remains unknow whether retinal tissue perfusion occurs in patients with Alzheimer’s disease.The goal was to determine retinal tissue perfusion in patients with clinical Alzheimer’s disease(CAD).Methods...Background:It remains unknow whether retinal tissue perfusion occurs in patients with Alzheimer’s disease.The goal was to determine retinal tissue perfusion in patients with clinical Alzheimer’s disease(CAD).Methods:Twenty-four CAD patients and 19 cognitively normal(CN)age-matched controls were recruited.A retinal function imager(RFI,Optical Imaging Ltd.,Rehovot,Israel)was used to measure the retinal blood flow supplying the macular area of a diameter of 2.5 mm centered on the fovea.Blood flow volumes of arterioles(entering the macular region)and venules(exiting the macular region)of the supplied area were calculated.Macular blood flow was calculated as the average of arteriolar and venular flow volumes.Custom ultra-high-resolution optical coherence tomography(UHR–OCT)was used to calculate macular tissue volume.Automated segmentation software(Orion,Voxeleron LLC,Pleasanton,CA)was used to segment six intra-retinal layers in the 2.5 mm(diameter)area centered on the fovea.The inner retina(containing vessel network),including retinal nerve fiber layer(RNFL),ganglion cell-inner plexiform layer(GCIPL),inner nuclear layer(INL)and outer plexiform layer(OPL),was segmented and tissue volume was calculated.Perfusion was calculated as the flow divided by the tissue volume.Results:The tissue perfusion in CAD patients was 2.58±0.79 nl/s/mm^(3)(mean±standard deviation)and was significantly lower than in CN subjects(3.62±0.44 nl/s/mm^(3),P<0.01),reflecting a decrease of 29%.The flow volume was 2.82±0.92 nl/s in CAD patients,which was 31%lower than in CN subjects(4.09±0.46 nl/s,P<0.01).GCIPL tissue volume was 0.47±0.04 mm^(3) in CAD patients and 6%lower than CN subjects(0.50±0.05 mm^(3),P<0.05).No other significant alterations were found in the intra-retinal layers between CAD and CN participants.Conclusions:This study is the first to show decreased retinal tissue perfusion that may be indicative of diminished tissue metabolic activity in patients with clinical Alzheimer’s disease.展开更多
New frontiers about retinal cell transplantation for retinal degenerative diseases start from the idea that acting on stem cells can help regenerate retinal layers and establish new synapses among retinal cells.Defici...New frontiers about retinal cell transplantation for retinal degenerative diseases start from the idea that acting on stem cells can help regenerate retinal layers and establish new synapses among retinal cells.Deficiency or alterations of synaptic input and neurotrophic factors result in trans-neuronal degeneration of the inner retinal cells.Thus,the disruption of photoreceptors takes place.However,even in advanced forms of retinal degeneration,a good percentage of the ganglion cells and the inner nuclear layer neurons remain intact.This phenomenon provides evidence for obtaining retinal circuitry through the transplantation of photoreceptors into the subretinal region.The eye is regarded as an optimal organ for cell transplantation because of its immunological privilege and the relatively small number of cells collaborating to carry out visual activities.The eyeball's immunological privilege,characterized by the suppression of delayed-type hypersensitivity responses in ocular tissues,is responsible for the low rate of graft rejection in transplant patients.The main discoveries highlight the capacity of embryonic stem cells(ESCs)and induced pluripotent stem cells to regenerate damaged retinal regions.Recent progress has shown significant enhancements in transplant procedures and results.The research also explores the ethical ramifications linked to the utilization of stem cells,emphasizing the ongoing issue surrounding ESCs.The analysis centers on recent breakthroughs,including the fabrication of three-dimensional retinal organoids and the innovation of scaffolding for cell transportation.Moreover,researchers are currently assessing the possibility of CRISPR and other advanced gene editing technologies to enhance the outcomes of retinal transplantation.The widespread use of universally recognized safe surgical and imaging methods enables retinal transplantation and monitoring of transplanted cell growth toward the correct location.Currently,most therapy approaches are in the first phases of development and necessitate further research,including both pre-clinical and clinical trials,to attain favorable visual results for individuals suffering from retinal degenerative illnesses.展开更多
A main cause of vision loss in the elderly is age-related macular degeneration(AMD).Among the cellular,biochemical,and molecular changes linked to this disease,inflammation and angiogenesis appear as being crucial in ...A main cause of vision loss in the elderly is age-related macular degeneration(AMD).Among the cellular,biochemical,and molecular changes linked to this disease,inflammation and angiogenesis appear as being crucial in AMD pathogenesis and progression.There are two forms of the disease:dry AMD,accounting for 80–90%of cases,and wet AMD.The disease usually begins as dry AMD associated with retinal pigment epithelium and photoreceptor degeneration,whereas wet AMD is associated with choroidal neovascularization resulting in severe vision impairment.The new vessels are largely malformed,leading to blood and fluid leakage within the disrupted tissue,which provokes inflammation and scar formation and results in retinal damage and detachment.Micro RNAs are dysregulated in AMD and may facilitate the early detection of the disease and monitoring disease progression.Two recent reviews of micro RNAs in AMD had indicated weaknesses or limitations in four earlier investigations.Studies in the last three years have shown considerable progress in overcoming some of these concerns and identifying specific micro RNAs as biomarkers for AMD.Further large-scale studies are warranted using appropriate statistical methods to take into account gender and age disparity in the study populations and confounding factors such as smoking status.展开更多
The promising role of cellular therapies in the preservation and restoration of visual function has prompted intensive efforts to characterize embryonic, adult, and induced pluripotent stem cells for regenerative purp...The promising role of cellular therapies in the preservation and restoration of visual function has prompted intensive efforts to characterize embryonic, adult, and induced pluripotent stem cells for regenerative purposes. Three main approaches to the use of stem cells have been described： sustained drug delivery, immunomodulation, and differentiation into various ocular structures. Studies of the differentiation capacity of all three types of stem cells into epithelial, neural, glial and vascular phenotypes have reached proof-of-concept in culture, but the correction of vision is still in the early developmental stages, and the requirements for effective in vivo implementation are still unclear. We present an overview of some of the preclinical findings on stem-cell rescue and regeneration of the cornea and retina in acute injury and degenerative disorders.展开更多
基金Supported by grant from Fundamental Research Grant Scheme by Ministry of Higher Education(MoHE)600-IRMI/FRGS 5/3(101/2019).
文摘AIM:To investigate the stability of the seven housekeeping genes:beta-actin(ActB),glyceraldehyde-3-phosphate dehydrogenase(GAPDH),18s ribosomal unit 5(18s),cyclophilin A(CycA),hypoxanthine-guanine phosphoribosyl transferase(HPRT),ribosomal protein large P0(36B4)and terminal uridylyl transferase 1(U6)in the diabetic retinal tissue of rat model.METHODS:The expression of these seven genes in rat retinal tissues was determined using real-time quantitative reverse transcription polymerase chain reaction(RT-qPCR)in two groups;normal control rats and streptozotocininduced diabetic rats.The stability analysis of gene expression was investigated using geNorm,NormFinder,BestKeeper,and comparative delta-Ct(ΔCt)algorithms.RESULTS:The 36B4 gene was stably expressed in the retinal tissues of normal control animals;however,it was less stable in diabetic retinas.The 18s gene was expressed consistently in both normal control and diabetic rats’retinal tissue.That this gene was the best reference for data normalisation in RT-qPCR studies that used the retinal tissue of streptozotocin-induced diabetic rats.Furthermore,there was no ideal gene stably expressed for use in all experimental settings.CONCLUSION:Identifying relevant genes is a need for achieving RT-qPCR validity and reliability and must be appropriately achieved based on a specific experimental setting.
基金supported by the McKnight Brain Institute,NIH Center Grant P30 EY014801,UM Dean's NIH Bridge Award(UM DBA 2019-3)a grant from Research to Prevent Blindness(RPB)and the North American Neuroophthalmology Society.
文摘Background:It remains unknow whether retinal tissue perfusion occurs in patients with Alzheimer’s disease.The goal was to determine retinal tissue perfusion in patients with clinical Alzheimer’s disease(CAD).Methods:Twenty-four CAD patients and 19 cognitively normal(CN)age-matched controls were recruited.A retinal function imager(RFI,Optical Imaging Ltd.,Rehovot,Israel)was used to measure the retinal blood flow supplying the macular area of a diameter of 2.5 mm centered on the fovea.Blood flow volumes of arterioles(entering the macular region)and venules(exiting the macular region)of the supplied area were calculated.Macular blood flow was calculated as the average of arteriolar and venular flow volumes.Custom ultra-high-resolution optical coherence tomography(UHR–OCT)was used to calculate macular tissue volume.Automated segmentation software(Orion,Voxeleron LLC,Pleasanton,CA)was used to segment six intra-retinal layers in the 2.5 mm(diameter)area centered on the fovea.The inner retina(containing vessel network),including retinal nerve fiber layer(RNFL),ganglion cell-inner plexiform layer(GCIPL),inner nuclear layer(INL)and outer plexiform layer(OPL),was segmented and tissue volume was calculated.Perfusion was calculated as the flow divided by the tissue volume.Results:The tissue perfusion in CAD patients was 2.58±0.79 nl/s/mm^(3)(mean±standard deviation)and was significantly lower than in CN subjects(3.62±0.44 nl/s/mm^(3),P<0.01),reflecting a decrease of 29%.The flow volume was 2.82±0.92 nl/s in CAD patients,which was 31%lower than in CN subjects(4.09±0.46 nl/s,P<0.01).GCIPL tissue volume was 0.47±0.04 mm^(3) in CAD patients and 6%lower than CN subjects(0.50±0.05 mm^(3),P<0.05).No other significant alterations were found in the intra-retinal layers between CAD and CN participants.Conclusions:This study is the first to show decreased retinal tissue perfusion that may be indicative of diminished tissue metabolic activity in patients with clinical Alzheimer’s disease.
文摘New frontiers about retinal cell transplantation for retinal degenerative diseases start from the idea that acting on stem cells can help regenerate retinal layers and establish new synapses among retinal cells.Deficiency or alterations of synaptic input and neurotrophic factors result in trans-neuronal degeneration of the inner retinal cells.Thus,the disruption of photoreceptors takes place.However,even in advanced forms of retinal degeneration,a good percentage of the ganglion cells and the inner nuclear layer neurons remain intact.This phenomenon provides evidence for obtaining retinal circuitry through the transplantation of photoreceptors into the subretinal region.The eye is regarded as an optimal organ for cell transplantation because of its immunological privilege and the relatively small number of cells collaborating to carry out visual activities.The eyeball's immunological privilege,characterized by the suppression of delayed-type hypersensitivity responses in ocular tissues,is responsible for the low rate of graft rejection in transplant patients.The main discoveries highlight the capacity of embryonic stem cells(ESCs)and induced pluripotent stem cells to regenerate damaged retinal regions.Recent progress has shown significant enhancements in transplant procedures and results.The research also explores the ethical ramifications linked to the utilization of stem cells,emphasizing the ongoing issue surrounding ESCs.The analysis centers on recent breakthroughs,including the fabrication of three-dimensional retinal organoids and the innovation of scaffolding for cell transportation.Moreover,researchers are currently assessing the possibility of CRISPR and other advanced gene editing technologies to enhance the outcomes of retinal transplantation.The widespread use of universally recognized safe surgical and imaging methods enables retinal transplantation and monitoring of transplanted cell growth toward the correct location.Currently,most therapy approaches are in the first phases of development and necessitate further research,including both pre-clinical and clinical trials,to attain favorable visual results for individuals suffering from retinal degenerative illnesses.
文摘A main cause of vision loss in the elderly is age-related macular degeneration(AMD).Among the cellular,biochemical,and molecular changes linked to this disease,inflammation and angiogenesis appear as being crucial in AMD pathogenesis and progression.There are two forms of the disease:dry AMD,accounting for 80–90%of cases,and wet AMD.The disease usually begins as dry AMD associated with retinal pigment epithelium and photoreceptor degeneration,whereas wet AMD is associated with choroidal neovascularization resulting in severe vision impairment.The new vessels are largely malformed,leading to blood and fluid leakage within the disrupted tissue,which provokes inflammation and scar formation and results in retinal damage and detachment.Micro RNAs are dysregulated in AMD and may facilitate the early detection of the disease and monitoring disease progression.Two recent reviews of micro RNAs in AMD had indicated weaknesses or limitations in four earlier investigations.Studies in the last three years have shown considerable progress in overcoming some of these concerns and identifying specific micro RNAs as biomarkers for AMD.Further large-scale studies are warranted using appropriate statistical methods to take into account gender and age disparity in the study populations and confounding factors such as smoking status.
基金partially supported by the Zanvyl and Isabelle Krieger Fund,Baltimore,Maryland,USAIsrael Scientific Foundation,ISF(1189/12,NGC)
文摘The promising role of cellular therapies in the preservation and restoration of visual function has prompted intensive efforts to characterize embryonic, adult, and induced pluripotent stem cells for regenerative purposes. Three main approaches to the use of stem cells have been described： sustained drug delivery, immunomodulation, and differentiation into various ocular structures. Studies of the differentiation capacity of all three types of stem cells into epithelial, neural, glial and vascular phenotypes have reached proof-of-concept in culture, but the correction of vision is still in the early developmental stages, and the requirements for effective in vivo implementation are still unclear. We present an overview of some of the preclinical findings on stem-cell rescue and regeneration of the cornea and retina in acute injury and degenerative disorders.
