胎盘生长因子在早产儿视网膜病变纤维血管膜中的表达

目的　研究胎盘生长因子（ｐｌａｃｅｎｔａｌｇｒｏｗｔｈｆａｃｔｏｒ,ＰＬＧＦ）在早产儿视网膜病变（ｒｅｔｉｎｏｐａｔｈｙｏｆｐｒｅｍａｔｕｒｉｔｙ,ＲＯＰ）纤维血管膜的血管内皮细胞、周细胞、巨噬细胞和胶质细胞中的表达和分布。方法　玻璃体切割术中取ＲＯＰ患者视网膜表面纤维血管膜保存备用,冰冻切片,ＨＥ染色、免疫组织化学染色和免疫荧光染色观察ＰＬＧＦ在纤维血管膜上的表达和分布。结果　ＨＥ染色及免疫组织化学染色结果显示ＰＬＧＦ在纤维血管膜中可见阳性表达。免疫荧光双标记法实验结果显示纤维血管膜的ＰＬＧＦ可能由血管内皮细胞、周细胞、巨噬细胞和胶质细胞表达。结论　ＰＬＧＦ可能参与了ＲＯＰ的发病过程,ＰＬＧＦ在ＲＯＰ发病中的作用及其分子机制需要进一步研究。     

Experimental studies on the pathogenesis of retinopathy of prematurity.

The angiogenic activity of various parts of the retina in kittens with oxygen-induced retinopathy has been studied by the use of a corneal micropocket technique and chorioallantoic assay. The results indicate that in retinopathy of prematurity the most important role in the pathogenesis of fibrovascular proliferation is played by the so-called primary avascular retina, that is, that part of the retina which has not yet been vascularised during ontogenesis.     

Neovascularization from scleral wound as cause of vitreous rebleeding after vitrectomy for proliferative diabetic retinopathy

PURPOSE: To determine the site of rebleeding into the vitreous after vitrectomy in patients with diabetic retinopathy. METHODS: We studied in detail 4 eyes of 4 patients in whom rebleeding into the vitreous followed successful vitrectomy for proliferative diabetic retinopathy. In addition, the fibrous membrane removed at surgery was studied by light and electron microscopy. RESULTS: In these 4 eyes, the second operation revealed that the source of the vitreous rebleeding was from a fibrovascular proliferation around the scleral wounds of the initial surgery, and no other neovascularization and/or reproliferation were observed in the whole retina. Rebleeding in these 4 eyes developed at an average of 9 weeks after initial surgery. The proliferative membrane was oval in shape and expanded from the residual vitreous that had been incarcerated in the scleral wound. The proliferative membrane removed during vitrectomy was poor in cellular components and contained extracellular matrix. Blood vessels of various sizes were also present. Electron microscopy showed the membrane was rich in extracellular components and contained high and low electron density cells. These cells often had microvilli and seemed to be of epithelial origin. CONCLUSIONS: These findings show that vitreous rebleeding may develop from fibrovascular proliferation from the scleral wound created during initial surgery. The proliferated membrane showed histological similarities with the fibrovascular proliferation usually seen in the diabetic retina and may represent a type of anterior proliferation secondary to retinal ischemia.     

Oxygen-induced retinopathy in the rat model

Identification of a suitable animal model is essential for the continued study of retinopathy of prematurity (ROP). Since 1984 we have used the newborn rat for the study of oxygen-induced retinopathy (OIR). The rat retina is highly immature at birth. Like those of humans, the retinal vessels arise from mesenchymal precursors, but contrary to that which occurs in humans, canalization of the rats inner retinal vessels is not related to the presence of cystoid spaces. In addition, only immature Stage I photoreceptors are present around the optic disk at birth. This extreme immaturity makes the rat retina highly susceptible to direct damage from oxygen. Oxygen-induced retinopathy can be produced by exposing the newborn rat to 80% oxygen for the first 7–10 days of life. We have demonstrated that OIR does not develop when oxygen is administered under conditions of moderate hyperbarism (+ 1.8 atm). It is possible that hyperbarism exerts a protective effect on the immature retinal vessels by inducing a vasoconstrictive response which reduces the amount of oxygen transported from the choroid to the inner retina during hypoxia. I recently hypothesized that this vasoconstriction might also affect the ciliary body, thus reducing the quantity of aqueous produced, and we are currently studying the relationship between development of the immature retinal vessels in the rat and production and drainage of the aqueous. The question we are attempting to answer is whether a condition of relatively increased intraocular pressure is capable of promoting the development of OIR.     

VEGF localisation in diabetic retinopathy

AIM—To determine the staining pattern of vascular endothelial growth factor (VEGF) at different stages of diabetic retinopathy (including post-laser photocoagulation) and to compare staining in excised fibrovascular and fibrocellular (non-diabetic) preretinal membranes.
METHODS—Immunohistochemical localisation of VEGF, using antibodies raised against VEGF₁₆₅ and VEGF_121,165,189, was carried out on specimens of normal human retina (n=15), diabetic retinas ((a) with no overt retinopathy (n=19), (b) with intraretinal vascular abnormalities but no proliferative retinopathy (n=6), (c) with active proliferative retinopathy (n=6), (d) with no residual proliferative retinopathy after photocoagulation therapy (n=15)), excised diabetic fibrovascular membranes (n=19), and non-diabetic fibrocellular membranes (n=7). The degree and pattern of immunostaining was recorded.
RESULTS—In general, VEGF was absent from the majority of normal retinas. VEGF staining was apparent in most diabetic tissues but the staining pattern was dependent on both the specificity of the antibody used and the category of tissue. Staining with the VEGF₁₆₅ antibody was generally confined to endothelial cells and perivascular regions while the VEGF_121,165,189 antibody was also associated with extravascular components of the inner retina. Intensity of immunostaining of diabetic eyes was dependent on the severity of retinopathy being least in diabetics with no overt retinopathy and greatest in retinas with proliferative retinopathy. Interestingly, the intensity of immunostaining in diabetic retinas which had undergone laser surgery for proliferative retinopathy was reduced to basal levels. Moderate to intense immunostaining was observed in all fibrovascular and fibrocellular membranes examined.
CONCLUSIONS—This study supports a circumstantial role for VEGF in the pathogenesis of both the preclinical and proliferative stages of diabetic retinopathy.

Keywords: vascular endothelial growth factor; VEGF; diabetes; diabetic retinopathy     

外泌体在眼底疾病发病及治疗中的作用

外泌体是细胞内的多囊泡体通过与细胞质膜融合后主动分泌到细胞外的小囊泡。外泌体内含有多种活性物质,其在细胞间通讯、疾病进展及作为生物标记物方面的作用已渐被眼底疾病的学者关注。研究显示外泌体参与了湿性年龄相关性黄斑变性病理过程,而间充质干细胞外泌体能够降低湿性年龄相关性黄斑变性患者的血管内皮生长因子转录和翻译;在大鼠糖尿病性视网膜病变血浆中研究发现含有IgG的外泌体可激活视网膜内的经典补体途径促进内皮损伤,应用含有miR-126间充质干细胞衍生的外泌体可限制内皮细胞损伤;在缺血性视网膜病变研究中骨髓间充质干细胞的外泌体可使缺血模型鼠视网膜功能恢复;玻璃体切除联合人脐带组织分离的间充质干细胞外泌体填塞对黄斑裂孔具有辅助治疗作用;视网膜脱离患者使用间充质干细胞分泌的外泌体可抑制光感受器细胞的凋亡;在葡萄膜黑色素瘤患者中外泌体标记物检测有希望成为葡萄膜黑色素瘤的早期诊断手段;在早产儿视网膜病变中小胶质细胞分泌的外泌体具有保护作用等。对外泌体系统的了解及其与眼底疾病中的信号传递机制及疾病转归过程的认识,对优化眼底疾病防治具有重要意义。（国际眼科纵览,2020, 45：442-448）     

Late traction detachment in retinopathy of prematurity or ROP-like cases

Five cases of traction retinal detachment occurring later in life as a sequel of cicatricial retinopathy of prematurity or showing the clinical picture of retinopathy of prematurity are reported. They presented with taut membranes in vitreous cavity, causing traction retinal detachment, and often showed preretinal membranes. These membranes were collagen-rich and contained cells with glial characteristics. They seemed to be continuously produced on the surface of the retina from which they detached sometimes in multiple generations. It is likely that chronic exudation from vascular abnormalities is a stimulus for this proliferation. These cases are very similar to other vitreoretinal proliferations in association with vascular abnormalities (Coats' and von Hippel disease, exudative vitreoretinopathy). Supported by: Helena Rubinstein Foundation, N.Y., and Research to Prevent Blindness, N.Y.Presented at the Club Jules Gonin, Vienna, Austria, September 9, 1992     

Cryotherapy for retinopathy of prematurity: timing of intervention.

This is a retrospective study of the results of cryotherapy for retinopathy of prematurity in 30 eyes of 17 patients from November 1976 to March 1983. The report is in the language of the international classification of retinopathy of prematurity. Ten eyes were treated at stage 4 disease, seven eyes at severe or late stage 3 'plus' disease, and 13 eyes at moderate or mid-stage 3 'plus' disease. All eyes had the cryotherapy applied to the ridge and the extraretinal fibrovascular proliferation contiguous with the ridge, some with additional treatment of the avascular retina. The results show that this method of treatment must be applied before severe stage 3 'plus' disease is established in order to prevent visual disability and minimise retrolental fibroplasia. The treatment of the selected cases of progressive moderate stage 3 'plus' disease accomplished those objectives.     

Management of proliferative diabetic retinopathy

Proliferative diabetic retinopathy is characterized by neovascularization originating from the retina and/or optic disk in patients with diabetes mellitus. The role of vascular endothelial growth factor appears to be central in the pathogenesis of proliferative diabetic retinopathy. Advanced glycation end products are important in the development of vitreous abnormalities in proliferative diabetic retinopathy. The majority of the neovascular membranes are adherent to the posterior vitreous cortex. When the posterior hyaloid exerts traction, the edges of the neovascular complex are pulled forward, resulting in vitreous hemorrhage. Tractional and/or rhegmatogenous retinal detachments can occur. The Diabetic Retinopathy Study demonstrated the ability of panretinal photocoagulation to reduce the rate of severe visual loss by 50% for eyes with high-risk characteristics, defined as neovascularization originating from the optic disk > 1/3 disk diameter, any neovascularization originating from the optic disk with hemorrhage, and neovascularization originating from the retina with vitreous hemorrhage. The Early Treatment Diabetic Retinopathy Study showed that patients with type II diabetes mellitus who were older than 40 with severe nonproliferative diabetic retinopathy (defined as hemorrhages in four quadrants, venous beading in two quadrants, or intraretinal microvascular abnormalities in one quadrant) also benefited from early panretinal photocoagulation. The Diabetic Retinopathy Vitrectomy Study showed that early vitrectomy (within 6 months of onset of vitreous hemorrhage) was associated with better results in type I diabetes mellitus patients only. The goals of vitreous surgery are to remove the vitreous, including the posterior hyaloid, and to relieve traction from fibrovascular tissue. Delamination and segmentation techniques have been used in the excision of fibrovascular growth on the internal limiting membrane and extending into the vitreous. Panretinal photocoagulation is an integral component of vitrectomy for proliferative diabetic retinopathy. Anti-vascular endothelial growth factor agents may be used in addition to laser as an adjunct to reduce the risk of neovascularization. Vitrectomy surgery may have intraoperative and postoperative complications, including cataract, anterior hyaloidal fibrovascular proliferation, fibrovascular ingrowth, retinal detachment, and recurrent vitreous hemorrhage. Visual potential depends on the preoperative and postoperative status of the macula, as well as on retinal perfusion and the health of the optic nerve. With the improvement in instruments, techniques, and drugs, the results of vitrectomy in proliferative diabetic retinopathy are improving.     

Chronic retinopathy of prematurity

A pathologic analysis of 40 autopsy cases of chronic retinopathy of prematurity is presented. The type of retinal detachment in chronic retinopathy is unique, resulting from progressive changes in the peripheral retina: folding at the site of extraretinal vasoproliferation; scroll-like rolling anteriorly towards the lens; foreshortening of entire retina with detachment; and closure of the retinal "funnel." The biomechanical intraretinal and extraretinal factors operating during this process are discussed. Also presented are some interesting atypical features found in this series: arrested retinopathy; "sea fan" extraretinal vascular fronds; retinopathy in anencephaly; cribriform vanguard; and extramedullary erythropoiesis.     

Histopathology findings following retinal tack implantation

For the first time this report describes the histopathological findings 2 months after retinal-tack implantation in a human eye. A stainless-steel tack was implanted to seal a small retinal tear during vitrectomy because of severe proliferative diabetic retinopathy in a 38-year-old man. By gross examination the enucleated eye showed a total retinal detachment except at the site where the tack had been implanted. Histologically a fibrovascular tissue proliferation arising from the choroid had grown into the adjacent retina at the tack site. No inflammatory reaction, pigment epithelium proliferation or glial-cell proliferation attributable to the tack were observed.     

Expression of ephrinB2 and its receptors on fibroproliferative membranes in ocular angiogenic diseases

PURPOSE: To determine whether ephrinB2 plays a role in ocular angiogenesis, we investigated the expression of ephrinB2 and EphB receptors on retinal fibroproliferative membranes. DESIGN: Experimental study of the expression of ephrinB2 and EphB receptors within fibroproliferative membranes in patients with ocular angiogenic diseases collected during vitrectomy. METHODS: Fibroproliferative membranes were obtained at the time of vitrectomy from 20 patients with proliferative diabetic retinopathy (PDR) and from 40 patients who had stage 5 retinopathy of prematurity. Specimens were investigated with immunohistochemistry using polyclonal antibodies directed against ephrinB2 and the EphB2, EphB3, and EphB4 receptors. Immunoreactivity for von Willebrand factor (factor VIII) and alpha-smooth muscle actin (alpha-SMA) was also determined to confirm the identity of the target vascular endothelial cells. RESULTS: Positive staining for ephrinB2 was observed on fibroproliferative membranes that were obtained from patients with PDR (65.0%) and retinopathy of prematurity (25.0%). Specifically, ephrinB2 was found to be present on endothelial cells, as confirmed by its colocalization with factor VIII and alpha-SMA staining. EphB2 and EphB3 expression was observed on fibroproliferative membranes that were harvested from patients with PDR (EphB2, 90.0%; EphB3, 70.0%) and retinopathy of prematurity (EphB2, 35.0%; EphB3, 45.0%). However, EphB4 expression was not observed in any of the membranes derived from patients with PDR or retinopathy of prematurity. The rate of ephrinB2 expression in patients with PDR was significantly higher than that seen in patients with retinopathy of prematurity, which probably reflected differences in the vascular density of their fibroproliferative membranes. CONCLUSION: These data suggest that the ephrinB2-EphB2/B3 system may play an important role in ocular angiogenesis.     

Retina-specific expression of PDGF-B versus PDGF-A: vascular versus nonvascular proliferative retinopathy

PURPOSE: Platelet-derived growth factor (PDGF) has been implicated in vascular proliferative retinopathies, such as diabetic retinopathy, and in nonvascular retinopathies, such as proliferative vitreoretinopathy. Traction retinal detachment is a central feature of both types of disease. Hemizygous rhodopsin promoter/PDGF-B (rho/PDGF-B) transgenic mice exhibit proliferation of vascular cells, glia, and retinal pigmented epithelial (RPE) cells, resulting in traction retinal detachment. Hemizygous rho/PDGF-A transgenic mice show mild proliferation of glial cells and no traction retinal detachments. This study was undertaken to determine whether higher levels of endogenously produced PDGF-A in the retinas of mice result in retinal detachment. METHODS: To achieve high-level expression of PDGF-A in the retina, homozygous rho/PDGF-A (rho/PDGF-AA) mice were generated. The phenotype of these mice was compared with that of homozygous rho/PDGF-B (rho/PDGF-BB) mice and double hemizygous rho/PDGF-B-rho/PDGF-A (rho/PDGF-AB) mice. RESULTS: Rho/PDGF-BB and rho/PDGF-AB mice showed a phenotype similar to that previously described in rho/PDGF-B mice. There was extensive proliferation of glial and vascular cells, resulting in fibrovascular membranes that detached the retina. PDGF-AA mice showed extensive proliferation of glial cells and traction retinal detachment. CONCLUSIONS: High retinal expression of PDGF-A results in extensive proliferation of glial cells and traction retinal detachment without vascular cell involvement, similar to proliferative vitreoretinopathy in humans. High retinal expression of PDGF-B results in traction retinal detachment from proliferation of both vascular and nonvascular cells, similar to diabetic retinopathy in humans.     

超未成熟儿视网膜病变术后屈光状态分析

目的　研究出生体质量＜１０００ｇ的早产儿视网膜病变患儿经过抗血管内皮生长因子玻璃体内注射后矫正胎龄６个月大时的眼位、注视功能及屈光状态情况。方法　横断面研究,回顾性队列研究。出生体质量＜１０００ｇ、因早产儿视网膜病变接受抗血管内皮生长因子玻璃体内注射的３２例（６４眼）患儿,于矫正胎龄６个月大时检查其注视功能、眼位,并散瞳验光。按治疗前眼底有无纤维增殖进行分组,观察两组屈光性弱视发生风险有无统计学差异。结果　矫正胎龄６个月大时,３２例６４眼中近视眼者２９眼（４５．３％）,近视度数为－０．７５～－４．００（－２．０３±０．７１）ＤＳ;远视眼３２眼（５０．０％）,远视度数为＋１．００～＋４．００（＋１．７８±０．７６）ＤＳ;存在或合并散光者２８眼（４３．８％）,散光度数为１．００～６．００（２．３９±１．１３）ＤＣ。所有患儿均为正位眼且中心注视,无注视抑制;治疗前眼底纤维增殖组中,有屈光性弱视风险的比例为７５．０％（１２／１６）;无纤维增殖组中,有屈光性弱视风险的比例为２５．０％（４／１６）,两者相比差异具有统计学意义（Ｐ＝０．０３２）。结论　出生体质量＜１０００ｇ早产儿接受抗血管内皮生长因子玻璃体内注射术后矫正胎龄６个月大时,表现出中心注视及正位眼,无注视抑制。治疗前眼底纤维增殖组发生屈光性弱视的风险大于无纤维增殖组。     

Hyperoxemic retinal neuronal necrosis in the premature neonate

A cytologically distinctive type of acute hyperoxemic injury of retinal neurons occurs in premature neonates. Ganglion cells in the central well-vascularized neonate retina are susceptible to excessive oxygen and this is expressed morphologically by karyorrhexis of their nuclei. We observed retinal neuronal necrosis in neonates who had hyperoxemia of greater than 150 torr for two hours or longer in the first week of life. Neuronal necrosis was strikingly associated with immaturity as determined by gestational age and birth weight: of 30 involved neonates, all were below 2,000 g; of 47 autopsied premature infants with birth weights under 1,500 g who survived for at least two days, 26 (55%) had acute retinal necrosis. When gestational age was used as a measure of prematurity, the highest incidence occurred in the 24- to 27-week group where 13 of 21 (62%) were involved. Hyperoxemic karyorrhectic changes, most prominent in the ganglion cells of the macula, are distinct from the classic peripheral mesenchymal vascular abnormalities of retinopathy of prematurity.     

Acoustic studies in proliferative diabetic retinopathy

Based on analysis of published reports and his own experience of acoustic studies (B-method) in more than 500 patients with proliferative diabetic retinopathy, the author concludes that preretinal fibrovascular membranes (posterior detachment of the hyaloid membrane with neovascularization) are often mistaken for retinal detachment. Acoustically detected solitary or multiple adhesions between fibrovascular and eye membranes are an important differential diagnostic sign indicating the absence of retinal detachment. These adhesions result from gradual staged "creeping" posterior vitreal detachment and indicate the sites of previous contact of the hyaloid membrane with the retina. In subtotal detachment of the retina there are no adhesions with ocular membranes and the retina acquires the configuration of a rigid fibrovascular membrane.     

Efficacy of cryotherapy for retinopathy of prematurity.

This is a retrospective study of the benefit of transconjunctival cryotherapy for retinopathy of prematurity (ROP) in 43 eyes of 22 infants (birth weight 716-1675 g) from July 1985 to January 1988. Nine eyes were treated at ROP stage 4A (early), 14 eyes at stage 3 plus disease, and 20 eyes at stage 3. Cryotherapy was applied to the retinal avascular zone. In 13 eyes the ridge of extraretinal fibrovascular proliferation was also treated. Two eyes with peripheral exudative retinal detachment in two quadrants had additional treatment of the area of elevated retina. Reexamination was performed at the age of 26 to 52 months (average 38 months). Regression of the ROP was found in all eyes. Seven eyes showed a lateral traction of the temporal vascular arcades, six of these eyes had a slight macular ectopia. None of the eyes progressed to stage 4B or 5. Visual acuity was 6/60 or better. Twelve children (60%) achieved 6/18 or better and 5 (25%) 6/9 or more. Our data indicate that cryotherapy for ROP grade 3 and early stage 4A prevents the progression to advanced stages. The results also imply a functional benefit of cryotreatment in infants with progressive severe ROP.     

The rationale for cryotherapy with a prophylactic scleral buckle for Zone I threshold retinopathy of prematurity

Our current surgical protocol for Zone I threshold retinopathy of prematurity (ROP) has evolved over 15 years and is rationalized by increasing knowledge of two pathologic processes of ROP: 1) angiogenic stimulation of spindle cells (clinically invisible) near the vitreal surface of the avascular retina; and 2) tractional forces of myofibroblasts [clinically visible as extraretinal fibrovascular proliferation (EFP)] in the vitreous overlying the vascular retina. These two pathologic processes occur concomitantly with normal anterior ocular growth with a constant optic disc-macular distance. Our current surgical protocol for Zone I threshold ROP. involves complex surgeries to achieve success defined as a macula which always remains anatomically attached, but which may be distorted or ectopic. This protocol requires cryotherapy in at least two sessions. The first is to the avascular retina to destroy spindle cells. The second is to the EFP to destroy myofibroblasts and to the shunt to eliminate the site of origin of myofibroblasts. The protocol also requires the concomitant placement of a prophylactic scleral buckle to allow formation of a new complete ora serrata while remnant myofibroblasts contract and while anterior ocular growth continues.     

Expression of Pigment Epithelium-Derived Factor and Vascular Endothelial Growth Factor in Fibrovascular Membranes from Patients with Proliferative Diabetic Retinopathy

Purpose

The expression of pigment epithelium-derived factor (PEDF), a strong inhibitor of angiogenesis, has not been examined in human ocular fibrovascular membranes, to the best of our knowledge. The purpose of this study was to determine whether PEDF is expressed in the fibrovascular membranes in eyes of patients with proliferative diabetic retinopathy (PDR), and to compare the expression of PEDF with that of vascular endothelial growth factor (VEGF).

Methods

The expression of PEDF and VEGF in the fibrovascular membranes excised during vitreous surgery in eight cases of PDR was determined by immunohistochemistry.

Results

VEGF was strongly expressed in the endothelial cells of newly formed vessels in the fibrovascular membranes. In contrast, PEDF was weakly expressed in the endothelial cells and was prominently expressed in the extracellular matrix and fibrous tissue surrounding the new vessels.

Conclusions

Our results suggest that PEDF, along with VEGF, may modulate the formation of fibrovascular membranes in patients with PDR.?Jpn J Ophthalmol 2006;50:116–120 © Japanese Ophthalmological Society 2006