Long-Term Ultrastructural Outcomes of Autologous Transplantation of Retinal Pigment Epithelium-Partial Thickness Choroid (RPE-PTC) Sheet in Rabbits.

BACKGROUND: To observe the ultrastructural outcomes of autologous transplantation of retinal pigment epithelium-partial-thickness choroidal (RPE-PTC) sheets in rabbits after 6 months. METHODS: Eighteen pigmented rabbits were used in this study. Among them, nine rabbits were used for autologous transplantation of RPE-PTC sheets. Tissue sections were observed under a transmission electron microscope for one, three, and six months after transplantation, respectively. RESULTS: One, three, and six months after the autologous transplantation of RPE-PTC sheets, the inner and outer segments of photoreceptor cells were arranged regularly, and the connection between the inner and outer segments was normal. The inner structure of the RPE cells and tight junctions among them remained normal. Phagocytosis of outer segment of photoreceptor cells could also be observed in RPE cells. The structure of the Bruch's membrane appeared loose, rather than being dense as normal, and it was undulated after one and three months, while it became dense after six months. The graft and the bed were healed well, the boundary was unclear, and the graft was vascularized after one, three, and six months, respectively. CONCLUSIONS: Our findings revealed that the RPE-PTC sheets could quickly rebuild blood vessels, thereby maintaining the normal physiological functions of RPE cells, as well as the survival and functional status of photoreceptor cells for a long-time.

A comparison of autologous transplantation of retinal pigment epithelium (RPE) monolayer sheet graft with RPE-Bruch's membrane complex graft in neovascular age-related macular degeneration.

PURPOSE: To compare the outcome after choroidal neovascular (CNV) membrane excision and retinal pigment epithelium (RPE) transplantation and make further evaluation of two types of RPE grafts on the visual function in patients with neovascular age-related macular degeneration (AMD), complicated by massive subretinal haemorrhage. METHODS: We retrospectively reviewed 80 patients who underwent CNV membrane excision with or without RPE transplantation. Two types of RPE grafts were adopted, RPE-Bruch's membrane complex graft (subgroup 1) and RPE monolayer sheet graft (subgroup 2). Outcome measures included pre- and postoperative visual acuity score (VAS), clinical findings, complications and recurrence rates. RESULTS: The mean VAS [Early Treatment of Diabetic Retinopathy Study (ETDRS)] in the CNV membrane excision group was 11.06 ± 18.28 at baseline and 14.41 ± 16.86 at follow-up (p = 0.12) in a mean follow-up period of 24.35 ± 9.31 months. While in subgroup 1, VAS increased from 22.62 ± 23.72 to 35.50 ± 24.46 (p = 0.02) in a mean period of 20.63 ± 6.25 months. The percentage of visual acuity (VA) improvement (at least two or more lines changed) in subgroup 1 is 62.5%, which is significantly higher than that in CNV excision group (23.5%), p = 0.02. In subgroup 2, VAS increased from 16.61 ± 27.98 to 29.16 ± 23.80 (p = 0.02) in a mean period of 21.72 ± 11.09 months. The percentage of VA improvement in subgroup 2 is 58.0%, which is also significantly higher than that in CNV excision group (23.5%), p = 0.02. Postoperative VA elevation was comparable between the two subgroups (p = 0.05). Complications including retinal detachment, proliferative vitreal retinopathy and CNV recurrence occurred in both techniques. Central fixation stability was observed in eight eyes in subgroup 1 and five eyes in subgroup 2. CONCLUSIONS: The autologous RPE transplantation can increase the vision of patients with haemorrhagic AMD. Two types of autologous RPE grafts were both effective and comparable in restoring visual function and central fixation stability.

Assessment of 180° rotation of the choroid as a novel surgical treatment for age-related macular degeneration.

PURPOSE: Our objective was to examine the feasibility of rotating choriocapillaris, Bruch's membrane (BM), and retinal pigment epithelium (RPE) through 180° on a vascular pedicle and to assess revascularization and tissue preservation postoperatively. Such an approach could be used in the treatment of age-related macular degeneration where there is focal disease at the macula with healthy tissues located peripherally. METHODS: Successful surgery was performed in six rhesus macaque monkeys, which have a very similar choroidal blood supply to humans. After inducing a retinal detachment, the recurrent branch of the long posterior ciliary artery was used as a pedicle around which a graft stretching to the temporal equator was rotated. Retina was reattached over the rotated graft and eyes were followed up for up to 6 months with repeated angiography and optical coherence tomography (OCT). The morphology of retinal cells and BM were assessed by immunohistochemistry and electron microscopy. RESULTS: Revascularization of the choroid was limited, with reestablishment of drainage to the vortex veins seen in only one case. There was a secondary loss of the RPE and outer retina evident on histological analysis three months after surgery. The underlying BM however remained intact. CONCLUSIONS: Pedicled choroidal rotation surgery is technically feasible in vivo with intraoperative control of bleeding. However, lack of graft revascularization with the technique in its current form leads to neuroretinal and RPE tissue loss, and graft shrinkage. We found no evidence that rotational grafts are likely to improve the outcomes presently achieved with free graft techniques.

Sources of retinal pigment epithelium (RPE) for replacement therapy.

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.

Surgery for CNV and autologous choroidal RPE patch transplantation: exposing the submacular space.

BACKGROUND: To evaluate the feasibility of transplanting a full-thickness patch of choroid, choriocapillaries, Bruch's membrane and RPE (RPE-choroid FTAP) from the peripheral to the subfoveal area of the same eye, after performing a 180 degrees peripheral retinotomy and removing subfoveal choroidal neovascularization. Thereafter, to study the surgical complications, anatomical outcome and patch perfusion during follow-up. METHODS: A retrospective case series of 13 eyes of 13 consecutive patients with a follow-up of 4 to 20 months. All patients suffered from advanced subfoveal choroidal neovascularization and were non-responders to standard care. After performing a complete vitrectomy, a 180 degrees peripheral temporal retinotomy and the removal of subfoveal neovascularization, a FTAP of choroid, choriocapillaris, Bruch's membrane and the RPE were isolated from the mid periphery of the uveal bed, transpositioned under the fovea and covered with the retina. Patients received a complete ophthalmic examination, fluorescein angiography (FA), indocyanin green angiography (ICGA) and optical coherence tomography (OCT) during follow-up. RESULTS: An FTAP could be harvested in every eye and transplanted under the fovea. No intraoperative complications occurred. The FTAP was recognizable at FA, ICGA and OCT at each time point, up to 20 months postoperatively. Perfusion of the choroidal bed were observed into the FTAP during follow-up, from one week after surgery. CONCLUSION: The creation of an FTAP through a 180 degrees peripheral retinotomy is feasible and safe. The FTAP is vital and perfused. Further studies are needed to collect more data.

Autologous transplantation of retinal pigment epithelium-Bruch's membrane complex for hemorrhagic age-related macular degeneration.

PURPOSE: To evaluate a surgical procedure for patients with hemorrhagic age-related macular degeneration (AMD). METHODS: This procedure consisted of excision of the choroidal neovascular membrane and transplantation of autologous retinal pigment epithelium (RPE)-Bruch's membrane complex. The RPE-Bruch's membrane complex for transplantation was surgically developed by dissecting Bruch's membrane with the choriocapillaris from the medium size choroidal vessel layer at the midperipheral region of the choroid. Twenty-one eyes of 21 patients had this surgical procedure. Visual function tests included best corrected visual acuity (BCVA), multifocal (mf)ERG, and microperimetry. Optical coherence tomography (OCT), fluorescein angiography, and autofluorescence examinations were performed to study the status of the transplanted graft. RESULTS: Among the 21 eyes, 17 with complete clinical data and qualified follow-up durations, which were 20.35 +/- 10.31 months on average, were analyzed in this series. On the last follow-up visit, the mean for the ETDRS scores increased from 28.65 +/- 23.99 before surgery to 47.76 +/- 17.22 after surgery. Microperimetry showed that after surgery, seven eyes gained central fixation at the 12-month follow-up examination. However, two eyes lost their central fixation on the last follow-up visit. Fourteen (82.35%) of the transplanted patches preserved normal color without depigmentation. Among the 21 eyes, proliferative vitreoretinopathy (PVR) occurred in 3 (14.29%), and a recurrent neovascular membrane was observed in one eye (4.76%). CONCLUSIONS: The transplantation of the autologous RPE-Bruch's membrane complex can increase the visual acuity of patients with hemorrhagic AMD. The surviving transplanted graft with functional overlying retina was observed after surgery.

Autologous translocation of the choroid and retinal pigment epithelium in patients with geographic atrophy.

PURPOSE: To evaluate the functional and anatomical outcomes of autologous translocation of peripheral choroid and retinal pigment epithelium (RPE) in patients with geographic atrophy. DESIGN: Prospective nonrandomized study. PARTICIPANTS: Twelve consecutive patients with geographic atrophy secondary to age-related macular degeneration presenting with recent loss of reading vision. METHODS: An autologous peripheral full-thickness graft of RPE, Bruch's membrane, and choroid was positioned under the macula in patients with geographic atrophy. MAIN OUTCOME MEASURES: Functional tests included Early Treatment Diabetic Retinopathy Study distant vision, reading (Radner Test, measured as logarithm of the reading acuity determination [logRAD]), threshold static perimetry, and determination of the point of fixation. Fluorescein and indocyanine green angiography, autofluorescence, and optical coherence tomography served to evaluate the anatomical outcome in a 6-month follow-up (12 months in 7 patients). RESULTS: Preoperative visual acuity (VA) ranged from 20/800 to 20/40 (mean, 0.6+/-0.4 logarithm of the minimum angle of resolution), and reading vision from 1.1 to 0.5 logRAD (mean, 0.8+/-0.2). Three patients were unable to read. Six months after surgery, VA ranged from hand movements to 20/32, with an increase of > or =5 letters in 2 eyes. Two patients without reading ability preoperatively were able to read after surgery. Reading was possible in a total of 8 patients after 6 months (1.3-0.4 logRAD). In 7 patients who were observed for 1 year, VA remained stable (+/-1 line) in 5 eyes and decreased in 2 eyes between 6 months' and 1 year's follow-up. In all eyes but 2, revascularization was visible on indocyanine green angiography as early as 3 weeks after surgery. Autofluorescence of the RPE was independent of revascularization of the graft and persisted throughout follow-up. Four eyes had unstable fixation and/or extrafoveal fixation before surgery. Two of these eyes stabilized during follow-up. Areas overlying atrophic areas demonstrated low threshold sensitivities that persisted after translocation of a free graft with only limited recovery. Revisional surgery due to proliferative vitreoretinopathy was required in 5 eyes. CONCLUSIONS: The translocation of a full-thickness graft usually results in a vascularized and functioning graft in patients with geographic atrophy, although is associated with a high risk of complications and visual loss. Longer follow-up is necessary to learn about the long-term survival and functionality of the graft.

Histological evidence for revascularisation of an autologous retinal pigment epithelium--choroid graft in the pig.

BACKGROUND: Translocation of a free autologous graft consisting of retinal pigment epithelium (RPE), Bruch's membrane, choriocapillaris and choroid in patients with exudative age-related macular degeneration is currently being evaluated in clinical practice. Angiographic studies in these patients suggest that their grafts become revascularised. AIM: To investigate the histological evidence of revascularisation of the graft in a porcine model. METHODS: In 11 pigs (11 eyes), an RPE-choroid graft was translocated from the mid-periphery to an intact or an intentionally damaged RPE and Bruch's membrane at the recipient site. The eyes were enucleated 1 week or 3 months after surgery. Tissue sections were evaluated using immunohistochemistry. RESULTS: Bridging vessels between recipient layer and graft were identified from 1 week to 3 months after surgery. This reconnection occurred regardless of whether the Bruch's membrane of the recipient site was left intact or intentionally damaged at the time of transplantation. The vasculature of the graft appeared open and perfused. Vessels with transcapillary pillars and conglomerates of small new vessels were present in the graft. CONCLUSIONS: This study showed histological evidence for revascularisation by angiogenesis of a free autologous RPE-choroid graft.

Maculoplasty for age-related macular degeneration: reengineering Bruch's membrane and the human macula.

Age-related macular degeneration (AMD) is the leading cause of blindness in the western world. Over the last decade, there have been significant advances in the management of exudative AMD with the introduction of anti-VEGF drugs; however, many patients with exudative AMD continue to lose vision and there are no effective treatments for advanced exudative AMD or geographic atrophy. Initial attempts at macular reconstruction using cellular transplantation have not been effective in reversing vision loss. Herein we discuss the current status of surgical attempts to reconstruct damaged subretinal anatomy in advanced AMD. We reinforce the concept of maculoplasty for advanced AMD, which is defined as reconstruction of macular anatomy in patients with advanced vision loss. Successful maculoplasty is a three-step process that includes replacing or repairing damaged cells (using transplantation, translocation or stimulation of autologous cell proliferation); immune suppression (if allografts are used to replace damaged cells); and reconstruction or replacement of Bruch's membrane (to restore the integrity of the substrate for proper cell attachment). In the current article we will review the rationale for maculoplasty in advanced AMD, and discuss the results of initial clinical attempts at macular reconstruction. We will then discuss the role of Bruch's membrane damage in limiting transplant survival and visual recovery, and discuss the effects of age-related changes within human Bruch's membrane on the initial attachment and subsequent proliferation of transplanted cells. We will discuss attempts to repair Bruch's membrane by coating with extracellular matrix ligands, anatomic reconstitution of the inner collagen layer, and the effects of Bruch's membrane reconstruction of ultrastuctural anatomy and subsequent cell behavior. Lastly, we will emphasize the importance of continued efforts required for successful maculoplasty.

Autologous translocation of the choroid and retinal pigment epithelium in age-related macular degeneration.

PURPOSE: To evaluate the autologous translocation of peripheral choroid and retinal pigment epithelium (RPE) in 45 eyes of 43 patients with age-related macular degeneration (AMD). DESIGN: Prospective nonrandomized study. METHODS: All patients had visual loss due to AMD (n = 5 classic membranes, n = 14 occult, n = 2 mixed, n = 16 pigment epithelial detachment (PED), n = 5 subretinal hemorrhage, n = 3 geographic atrophy). After extraction of the neovascular complex, an autologous peripheral full-thickness explant of RPE, Bruch membrane, and choroid was translocated from the midperiphery to the macula. RESULTS: Preoperative distant visual acuity ranged from 20/800 to 20/40. Reading vision ranged from 1.4 logarithm of reading acuity determination (logRAD) to 0.5 logRAD (0.04 to 0.32 Snellen equivalent). Revision surgery was required in 22 eyes as a result of proliferative vitreoretinopathy (PVR), retinal detachment, macular pucker, or vitreous hemorrhage. In eight patients, the patch was renewed. At six months, distant visual acuity ranged from light perception to 20/50 (increase of 15 letters in four eyes). Reading vision ranged from 1.4 to 0.4 logRAD. Visual outcome was unrelated to the type of AMD. Vascularization of the transplant was visible on indocyanine green (ICG) angiography in 40 of 42 eyes. In most patients, autofluorescence of the pigment epithelium was coincident with revascularization of the graft. Fixation on the patch was positively related to visual acuity. CONCLUSIONS: Autologous translocation of a full-thickness transplant of choroid and RPE usually results in a vascularized and functioning graft. Vascularization was even achieved in patients with geographic atrophy. Fixation stability and microperimetry before the patch translocation may be helpful in selecting patients who will profit from surgery.

[Transplantation of retinal pigment pithelium (RPE) following CNV removal in patients with AMD. Techniques, results, outlook]. / Transplantation von retinalem Pigmentepithel (RPE) nach CNV-Exzision bei altersabhängiger Makuladegeneration. Techniken, Ergebnisse und Perspektiven.

Neovascular age-related macular degeneration (AMD) has become the leading cause for severe visual loss in all industrialized nations. Surgical excision of choroidal neovascularizations (CNV) is technically feasible but invariably associated with inadvertent removal of corresponding retinal pigment epithelium (RPE) and subsequent atrophy of the choriocapillaris, with the latter two layers being a prerequisite for normal photoreceptor function. To cover the RPE defect both heterologous and homologous RPE cell suspensions have been injected into the subretinal space. The lack of functional improvement has been attributed to various factors including RPE cell dedifferentiation, failure of adherence to Bruch's membrane as well as development of a regular RPE cell monolayer. Therefore, techniques for translocating intact autologous RPE cell sheets have been sought and preservation of foveal neurosensory functions has recently been successfully demonstrated. Besides translocation of a full-thickness RPE/Bruch's membrane/choroid patch outside the macular area, superfluous choroidal tissue may be ablated intraocularly using an excimer laser prior to translocation. Besides recent pharmacological approaches including anti-VEGF agents, these surgical developments open new perspectives for patients with neovascular AMD.

Autologous retinal pigment epithelium and choroid translocation in patients with exudative age-related macular degeneration: short-term follow-up.

PURPOSE: To evaluate the feasibilty of translocating autologous retinal pigment epithelium cells and choroid after the removal of a subfoveal choroidal neovascular membrane in patients with exudative age-related macular degeneration. DESIGN: Interventional case series. METHODS: This was a prospective evaluation of six patients with a follow-up of 7 to 13 months. All patients had large (> 1 disk diameter) subfoveal choroidal membranes, five with subretinal hemorrhage. Preoperative visual acuity ranged from 20/400 to 20/200. After the extraction of the neovascular complex, an autologous peripheral full-thickness patch of retinal pigment epithelium, Bruch membrane, choriocapillary, and choroid was cut out from the midperiphery and repositioned under the macula. Functional tests included Early Treatment Diabetic Retinopathy Study vision testing, fixation testing on a optical coherence tomography monitor, fluorescein and indocyanine green angiography, and scanning laser ophthalmoscopy autofluorescence. RESULTS: The retinal pigment epithelium patch appeared flat and had a brown furry aspect in four patients. Fixation was on the patch in these four patients. Postoperative vision ranged from 20/200 to 20/64, with a 2-line increase in three patients. Revascularization was visible on fluorescein and indocyanide angiography in three patients examined in this manner. Normal retinal pigment epithelium autofluorescence was present over the patch in four patients. CONCLUSIONS: The translocation of a full-thickness patch with autologous peripheral retinal pigment epithelium to the macula after choroidal neovascular membrane extraction was feasible and may result in a surviving and functioning graft for more than 1 year. Longer follow-up to evaluate its long-term benefit is necessary, as well as refinement of the surgery.