Nerve growth factor effect on human primary fibroblastic-keratocytes: possible mechanism during corneal healing

In response to corneal injury, cytokines and growth factors play a crucial role by influencing epithelial-stromal interaction during the healing and reparative processes which may resolve in tissue remodeling and fibrosis. While transforming growth factor-beta1 (TGF-beta1) is considered the main profibrogenic modulator of these process, recently the nerve growth factor (NGF) appears as a pleiotropic modulator of wound-healing and inflammatory responses. Interestingly in the cornea, where NGF, trkA(NGFR) and p75(NTR) are expressed by epithelial cells and keratocytes, the NGF eye-drop induces the healing of neurotrophic or autoimmune corneal ulcers. During corneal healing, quiescent keratocytes are replaced by active fibroblast-like keratocytes/myofibroblasts. While the NGF effect on epithelial cells has been investigated, no data are reported for NGF effects on fibroblastic-keratocytes, during corneal healing. NGF, trkA(NGFR) and p75(NTR) were found expressed by fibroblastic-keratocytes. NGF was able to induce fibroblastic-keratocyte differentiation into myofibroblasts, migration, Metalloproteinase-9 expression/activity and contraction of a 3D collagen gel, without affecting their proliferation and collagen production. These data also show a two-directional control of fibroblastic-keratocytes by NGF and TGF-beta1. To sum up, the findings of this study indicate that NGF can modulate some functional activities of fibroblastic-keratocytes, thus substantiating the healing effects of NGF on corneal wound-healing.     

形觉剥夺性近视豚鼠视网膜中神经生长因子及其受体的表达

目的 探讨视网膜神经生长因子（NGF）及其受体（TrkA）在豚鼠形觉剥夺性近视（FDM）视网膜中的表达.方法 对出生7 d豚鼠以半透明眼罩遮盖右眼2个月制备FDM动物模型,左眼作为对照.遮盖前及遮盖2、4、8周后,检影验光检测双眼屈光度,A型超声测量双眼眼轴长度.免疫组织化学和逆转录一聚合酶链式反应（RT-PCR）检测视网膜NGF和TrkA的表达变化.结果 形觉剥夺使豚鼠眼轴增长,近视屈光度增加,遮盖眼与对照眼相比屈光度差异有统计学意义（P＜0.01）.遮盖眼NGF与TrkA免疫活性逐渐降低,NGF与TrkAmRNA表达下调,与对照组比较差异有统计学意义（P＜0.01）.结论 NGF和TrkA可能参与调控FDM的形成.     

Immunohistochemical study of idiopathic and secondary epiretinal membrane]

PURPOSE: We investigated the immunohistochemical features of surgically resected idiopathic epiretinal membranes(ERMs) and secondary ERMs with regard to posterior vitreous detachment(PVD). METHODS: Six specimens of idiopathic epiretinal membranes(3 eyes with complete PVD, 2 eyes with partial PVD, and one eye with no PVD) and 3 specimens of secondary ERMs(all eyes with complete PVD) were immunohistochemically studied. We used type I, II, III, IV collagen and fibronectin to study extracellular components, and glial fibrillary acidic protein(GFAP), S 100 protein, vimentin, and so forth to study cellular components. RESULTS: All the specimens of idiopathic ERMs had the major components of the lamellar stained by type II collagen antibody, and one out of 3 specimens of secondary ERMs had a minor component stained by type II collagen antibody. Compared with idiopathic ERMs with complete PVD, 2 out of 3 specimens of idiopathic ERMs with partial PVD or no PVD contained rather thick collagen lamellar. CONCLUSION: There was difference between specimens of idiopathic ERMs and specimens of secondary ERMs in staining by type II collagen antibody, supposed by vitreous, in this study. Idiopathic ERM with attached posterior vitreous membrane may cause growth of collagen.     

Expression of glutamine synthetase and cell proliferation in human idiopathic epiretinal membrane

BACKGROUND/AIM: The mechanisms of the cellular origin and cell proliferation in the idiopathic epiretinal membrane (ERM) are unsolved. The aim of this study was to examine the expression of cell cycle related molecules and glutamine synthetase (GS), which is expressed in Müller cells and their processes, in ERM tissues. METHODS: The ERMs were surgically removed using pars plana vitrectomy. Formalin fixed, paraffin embedded ERM tissues were analysed by immunohistochemistry with anti-cyclin D1, p27 (KIP1), proliferating cell nuclear antigen (PCNA), and GS antibodies. RESULTS: The histopathological findings showed that all the ERMs consisted of oval or spindle mononuclear cells with thin collagen-like tissues. Immunoreactivity for GS was detected in collagen-like tissues of ERM, presenting a continuous, isodense pattern. GS immunopositive cells in all cases expressed PCNA in their nuclei. Nuclear immunoreactivity for cyclin D1 was noted in the ERM constituent cells, whereas p27 (KIP1) positive nuclei were not detected. CONCLUSION: Cyclin D1 and PCNA were expressed in the idiopathic ERM, which was mainly derived from Müller cells and extensions of their processes.     

Perifoveal microcirculation in eyes with epiretinal membranes

BACKGROUND/AIMS: Eyes with epiretinal membranes (ERMs) often have alterations of retinal vessels. The authors studied perifoveal microcirculation in eyes with epiretinal membranes (ERMs) using scanning laser ophthalmoscope (SLO) fluorescein angiography. METHODS: Mean capillary blood flow velocity (CFV) was measured as an index of perifoveal microcirculation by SLO fluorescein angiography in 26 eyes with ERMs (19 eyes with idiopathic epiretinal membranes, seven eyes with epiretinal membranes after retinal detachment surgery) before and 6 months after vitreous surgery, and in 23 healthy control subjects. RESULTS: The mean CFV was significantly reduced in eyes with ERMs compared with healthy controls (p=0.012), and the postoperative mean CFV was significantly increased compared with the preoperative mean CFV (p=0.041). CONCLUSION: Significant changes of capillary blood flow velocity in the perifoveal areas were observed between normal subjects and eyes with epiretinal membranes. This indicates that eyes with ERMs show abnormal haemodynamics in the perifoveal capillaries.     

Three-dimensional evaluation of vitreomacular traction and epiretinal membrane using spectral-domain optical coherence tomography

PURPOSE: To delineate the 3-dimensional (3-D) relationship in vitreomacular traction (VMT) and idiopathic epiretinal membrane (ERM). DESIGN: Observational case series. METHODS: Forty-eight evaluable eyes of 35 patients with VMT or idiopathic ERM were investigated with spectral-domain (SD) optical coherence tomography (OCT). VMT was defined as focal if the diameter of the vitreous attachment was 1500 microm or less and broad if it was more than 1500 microm. The 3-D OCT representation of vitreomacular interface abnormalities was evaluated. RESULTS: Focal VMT was seen in five eyes. Broad VMT was seen in seven eyes. Of these 12 eyes, concurrent ERMs under the detached vitreous were seen in 10 eyes and zones of hyperreflectivity affecting the adjacent detached posterior hyaloid face were seen in 11 eyes. Eyes with focal VMT showed a foveal cavitation, whereas eyes with broad VMT had more widespread cystoid macular edema. Idiopathic ERM was seen in 36 eyes; 30 had complete posterior vitreous detachment (PVD), five had partial PVD associated with attached posterior hyaloid at some peripheral portion of the ERM, and one had no PVD. CONCLUSIONS: The SD OCT with 3-D image reconstruction provided unprecedented visualization of VMT and idiopathic ERM. The vitreous attachment to the macula can be subclassified into two subgroups, each having specific induced alterations in retinal anatomy. Most of the eyes with VMT had concurrent ERM, whereas several eyes with idiopathic ERM had attachment of the vitreous to some portion of the ERM, which suggests there is significant overlap between VMT and idiopathic ERM.     

TGF-beta1, TGF-beta receptor II and ED-A fibronectin expression in myofibroblast of vitreoretinopathy

PURPOSE: Formation of scarlike epiretinal membranes (ERMs) constitutes potentially the end stage of evolution of proliferative vitreoretinopathy (PVR) and proliferative diabetic retinopathy (PDR). Among various cellular populations, ERMs contain cells with contractile features typical of myofibroblasts. The current study was conducted to investigate the presence of transforming growth factor (TGF)-beta1, TGF-beta receptor II (RII) and ED-A fibronectin (FN), the main inducers of myofibroblastic differentiation in ERMs in PDR and PVR. METHODS: Samples of ERM were obtained from 23 patients during microsurgery for PVR or PDR. Electron microscopy, immunohistochemistry, and confocal microscopy with antibodies recognizing beta-smooth muscle (SM) actin, desmin, TGF-beta1, TGF-beta receptors I and II, and ED-A FN were performed. RESULTS: alpha-SM actin was detected in all ERMs, whereas desmin was present in 50% of the cases. ED-A FN was expressed in all ERMs in close relation with alpha-SM actin-positive myofibroblasts. In addition, TGF-beta1 and TGF-beta R II were always present, TGF-beta RII being expressed in both alpha-SM actin-positive and negative fibroblastic cells. CONCLUSIONS: Myofibroblast accumulation is a key event in ERM-associated traction retinal detachment occurring during PVR and PDR. The current results suggest that the presence of alpha-SM actin-positive myofibroblasts is probably dependent on the concomitant neoexpression of TGF-beta1, TGF-beta RII, and ED-A FN. The results furnish new data on the mechanism of alpha-SM actin stimulation in fibroblasts in a human pathologic setting.     

The Preliminary Report of Pathological Changes of Epiretinal Membranes and Internal Limiting Membrane Removed during Idiopathic Macular Hole Surgery

Purpose:To investigate the pathological changes of epiretinal membranes(ERM)and internal limiting membrane(ILM)removed during idiopathie macular hole surgery.Methods:Ten consecutive patients with a unilateral idiopathic macular hole underwent pars plana vitrectomy(PPV)with the surgical removal of the ERMs overlying the hole and ILM surrounding the hole.The pathological features of the exciesed tissues were examined under the microscope.Results:According to the morphological changes,four ERMs showed cellular elements which looked like glia cells,macrophages,plasma cells,lymphocytes and fibroblast cells.Two of the ILM appeared as transparent membranes without cellular elements.The other eight ILM showed cellular elements on the transparent membranes.Conclusion:Our study supports the hypothesis that the tangential traction of vitreous and proliferative cellular elements on the inner surface of ILM causes indiopathic macular holes.Removal of the posterior cortical vitreous,ILM and proliferative cellular tissue is a valid treatment for IMH.     

Upregulation of RAGE and its ligands in proliferative retinal disease

We sought to study the presence of the receptor for advanced glycation endproducts (RAGE) and its ligands, advanced glycation endproducts (AGEs), S100/calgranulins and amphoterin (high mobility group box 1 protein; HMGB1), in the vitreous cavity and epiretinal membranes (ERMs) of eyes of patients with proliferative diabetic retinopathy (PDR) and proliferative vitreoretinopathy (PVR). Undiluted vitreous specimens were collected from 30 eyes of 30 patients undergoing pars plana vitrectomy for repair of retinal detachment (RD) secondary to PDR (n = 15) or PVR (n = 15). The vitreous samples obtained from 10 eyes undergoing macular hole repair were used as controls. Epiretinal membranes were obtained from eight eyes with PDR and from 10 eyes with PVR. The levels of AGEs in the vitreous were measured using ELISA. The vitreous levels of soluble RAGE (sRAGE), S100/calgranulins and amphoterin were measured using Western blot analyses. The localization of RAGE and its ligands in ERMs was determined with immunohistochemistry. The vitreous levels of sRAGE were significantly increased in both PDR and PVR (p < or = 0.05) compared to control vitreous. In both PDR and PVR, the vitreous levels of AGEs (p < or = 0.01), S100/calgranulins (p < or = 0.05), and amphoterin (p < or = 0.01) were also elevated compared to control eyes. Expression of RAGE was detected in six of eight ERMs from eyes with PDR and eight of 10 ERMs from eyes with PVR. Many cells expressing RAGE also expressed vimentin, suggesting a glial cell origin. Ligands for RAGE were also detected in ERMs, with AGEs detected in five eyes with PDR and eight eyes with PVR. Similarly, S100 and amphoterin ERM expression was observed in six eyes with PDR; these ligands were also expressed in ERMs from eyes with PVR (8 and 7 cases, respectively). We conclude that RAGE and its ligands are increased in the vitreous cavity of eyes with PDR and PVR and are present in ERMs of eyes with these proliferative retinal disorders. These findings suggest a role for the proinflammatory RAGE axis in the pathogenesis of proliferative retinal diseases.     

Vitrectomy with membrane peeling for vasocentric idiopathic epiretinal membranes

PURPOSE: To report the clinical course and outcome of surgery for idiopathic epiretinal membranes (ERMs) centered on retinal blood vessels. METHODS: Retrospective observational case series review of the case records of 15 patients with idiopathic ERMs overlying retinal blood vessels, of whom 9 underwent vitrectomy with membrane peeling. The patients attended two eye departments under the care of four vitreoretinal surgeons with a total of more than 50 years of surgical experience. RESULTS: The patients were aged 12-74 years (mean = 34.3 years). Difficulties were experienced in achieving vitreoretinal and membranoretinal separation in the 9 eyes undergoing vitreous microsurgery. Recurrent ERM formation occurred in 8 of these eyes (89%) of which 6 underwent revision vitrectomy. Visual improvement was achieved in 55% of patients. Mean follow-up was 2.5 years. CONCLUSIONS: The authors describe a subgroup of patients with idiopathic ERMs in which the membrane is centered over a large retinal vessel. This occurs predominantly but not exclusively in a young age group. Surgical removal is characterized by a high recurrence rate.     

Comparison of histopathological findings between idiopathic and secondary epiretinal membranes

To evaluate the histopathological findings of idiopathic and secondary epithelial membranes (ERMs). This study involved 19 ERM cases that underwent pars plana vitrectomy (PPV). ERM specimens were obtained from each patient during PPV and immediately fixed in 10 % formalin. Paraffin sections were stained with hematoxylin eosin (HE) and immunohistochemical analysis was performed with glial fibrillary acidic protein (GFAP), Ki-67, CD34, and nestin antibodies. The 19 ERM cases included 11 idiopathic ERM cases and 8 secondary ERM cases i.e., 2 eyes that underwent PPV for retinal detachment and 6 eyes that underwent PPV for proliferative diabetic retinopathy. HE staining showed that some of the idiopathic ERM specimens consisted of internal limiting membrane. In contrast, numerous invasive cells were observed in the secondary ERM specimens compared to the idiopathic ERM specimens. Immunohistochemical analysis revealed GFAP-positive cells in 4 of the 11 idiopathic ERMs cases, yet no nestin-, Ki-67-, or CD34-positive cells in those cases. In contrast, there were 4 GFAP-positive cases, 2 Ki67-positive cases, 3 CD34-positive cases, and 7 cases including nestin-positive cells. The findings of this study indicate that there are different histological characteristics between idiopathic and secondary ERM and that mature nestin-positive cells in the retina might be related to secondary ERM formation.     

The role of NGF signaling in human limbal epithelium expanded by amniotic membrane culture

PURPOSE: Amniotic membrane (AM) transplantation facilitates rapid epithelialization in severe neurotrophic corneal ulcers. To elucidate its action mechanism, we investigated the expression of ligands and receptors of the neurotrophin family by human limbal epithelial (HLE) cells expanded on AM cultures. METHODS: Expression of nerve growth factor (NGF); neurotrophins (NT)3 and NT4; brain-derived neurotrophic factor (BDNF); tyrosine kinase-transducing receptors TrkA, TrkB, and TrkC; and a pan-NT low-affinity receptor (p75(NTR)) was examined by immunostaining in the normal human corneolimbus, HLE grown on intact epithelially denuded AM, and stratified HLE, after subcutaneous implantation in NIH-bg-nu-xid BR mice. NGF protein level was assayed by an ELISA in extracts of intact and epithelially denuded AM. K252a, a specific inhibitor of TrkA autophosphorylation, was added to test whether it would inhibit HLE expansion on AM culture. RESULTS: Strong positive TrkA staining was confined to the basal epithelial cell layer of normal corneal and limbal epithelia, with the highest intensity noted in the limbus. TrkA staining was also strongly positive in the basal layer of HLE cells cultured on intact and epithelially denuded AM and in basal and some suprabasal layers of stratified HLE transplanted in nude mice. Positive staining of p75(NTR) was noted in the full-thickness of the corneal epithelium but was limited to the superficial layers of the limbus and in HLE cells cultured on intact and epithelially denuded AM, but was weak in HLE transplanted to nude mice. Weak staining of NT3 and TrkC was noted in the suprabasal layers of corneal and limbal epithelia but was negative in the stratified HLE in nude mice. Negative staining of NGF, NT4, BDNF, and TrkB was noted in all specimens tested. The NGF protein level was readily measured as 35.6 +/- 9.1 and 41 +/- 12.5 pg/mg protein in the homogenate of the intact and epithelially denuded AM, respectively (P = 0.0256). K252a significantly inhibited the HLE outgrowth on intact AM culture (P = 0.024). CONCLUSIONS: The strong expression of TrkA but not p75(NTR) in the limbal basal epithelial cells in vivo suggests that NGF signaling favors limbal epithelial stem cell survival. Such a phenotype is preserved in HLE cells on AM. Blocking NGF signaling significantly retarded HLE expansion on AM, supporting the notion that NGF is important in expansion of limbal epithelial progenitor cells. Furthermore, a high and therapeutic level of NGF was present in AM. Collectively, these findings indicate that denervated neurotrophic ulcers are associated with poor epithelial stem cell function at the limbus. Future studies are needed to determine whether AM transplantation to heal such ulcers may include the promotion of nerve regeneration and survival of epithelial progenitor cells.     

Advantages of confocal microscopy in the analysis of epiretinal membranes and internal limiting membranes after macular surgery

PURPOSE: To study specimens obtained from epiretinal membrane (ERM) and macular hole surgery with confocal microscopy and to evaluate its advantages in understanding their pathophysiology. MATERIAL AND METHODS: This retrospective study included 50 patients undergoing surgery for epiretinal membrane (40 patients) or idiopathic macular hole (10 patients). Infracyanine green was used in 45 cases. Immunohistological examination of the excised tissues was undertaken using confocal microscopy after labeling with antibodies to glial fibrillary acidic protein (GFAP) and vimentin. RESULTS: Confocal microscopic analysis of epiretinal membranes identified three types of tissues: 13 ERMs, which appeared thick and rich in cells, 20 internal limiting membranes (ILMs), which appeared thin, wrinkled and poor in cells, and seven composite tissues, where ERM and ILM were removed at the same time. The analysis of ten specimens obtained from macular hole surgery revealed nine ILMs and one composite tissue that were quite similar to those removed in epiretinal membrane surgery. In all, 27 specimens (10 ERMs, 12 ILMs and five composite tissues) contained GFAP-positive glial cells. CONCLUSION: The confocal microscope provided a fast, three-dimensional analysis of ERMs and ILMs. An immunohistological study identified cells that take part in the genesis of the membranes. Glial cells were found both in ERM and ILM specimens. Our findings suggest that Müller's cells may contribute to the pathogenesis of ERM and macular hole development.     

Comparison of epiretinal membranes of differing pathogenesis using optical coherence tomography

PURPOSE: To compare optical coherence tomography (OCT) images of idiopathic epiretinal membranes (ERMs) with those of secondary ERMs. METHODS: OCT was performed on 70 eyes of 63 consecutive patients with biomicroscopic evidence of ERMs and 23 eyes of 23 healthy volunteers without ERMs. OCT findings were correlated with the clinical pathogenesis of the ERM. RESULTS: Evaluation by OCT established that 48 of 70 ERMs were globally adherent to the retina and that 22 of 70 ERMs were focally adherent to the retina. When correlated to clinical pathogenesis, 20% of idiopathic membranes and 52% of secondary membranes were focally attached to the retina. There was a significant difference in the pattern of membrane attachment to the retina in the two pathogenic groups (P = 0.007). Eight of nine eyes with macular pseudoholes were associated with globally adherent membranes. CONCLUSION: Secondary ERMs are more likely to be characterized by focal retinal adhesion than are primary ERMs. Primary ERMs tend to be globally adherent. This finding may contribute to understanding the underlying mechanisms of ERM formation in different clinical settings.     

Idiopathic epiretinal membranes: cell type, growth factor expression, and fluorescein angiographic and retinal photographic correlations

BACKGROUND: We studied the cellular constituents and the expression of vascular endothelial growth factor (VEGF) and transforming growth factor-beta (TGF-beta2) in idiopathic epiretinal membranes (ERMs), attempting to correlate the presence of these growth factors with fluorescein leakage during angiography and with the amount of macular scar tissue. METHODS: Idiopathic ERMs were excised at vitrectomy in 41 consecutive cases and stained for glial fibrillary acidic protein (GFAP), vimentin, cytokeratin, desmin and actin. A subset of 13 cases for which fluorescein angiograms and colour retinal photographs were available was further studied for the presence of VEGF and TGF-beta2 in the ERMs, fluorescein leakage and amount of macular scar tissue. RESULTS: Of the 41 ERMs, 31 (76%) were found to be fibroglial by light microscopy; 40 (98%) stained for GFAP, 39 (95%) for vimentin, 10 (24%) for cytokeratin, 3 (7%) for desmin and 11 (27%) for actin. Of the 13 ERMs in the subset, staining was positive for VEGF in 11 (85%) and for TGF-beta2 in 11 (85%). There was no statistically significant relationship between the presence of VEGF and leakage (p = 0.68) or between the presence of TGF-beta2 and scar size (p = 0.90). When both VEGF and TGF-beta2 were present, there was likely to be leakage or a large scar, or both, which suggested that an interaction exists between the two growth factors (p = 0.057). When leakage occurred, large scars were 2.5 times less likely to be present; when no leakage occurred, large scars were 2.5 times more likely to be present (odds ratio 0.4; Yules association coefficient -0.43). INTERPRETATION: The cells constituting idiopathic ERMs were primarily fibroglial with minimal staining evidence for the presence of contractile proteins in their cytoplasm. VEGF and TGF-beta2 were present in 85% of specimens. Although there was no direct correlation between the presence of these growth factors and either fluorescein leakage or the abundance of scar tissue respectively, there was some evidence for the interaction of these growth factors in producing either leakage or abundance of scar tissue.     

Clinicopathologic correlation of recurrent epiretinal membranes after previous surgical removal

Recurrent epiretinal membranes (ERMs) causing macular pucker developed after surgical removal in seven eyes and were subsequently removed. A specimen was available for electron microscopic study from four of the seven primary operations and all seven of the repeat operations. The diagnostic associations for the primary cases included retinal holes or tears (four eyes), trauma, inflammation (one eye each). In one eye the membrane was idiopathic. The primary and recurrent ERM specimens contained similar cell types and structural characteristics but were not identical. No one cell type predominated in either primary or recurrent ERM. Compared with studies of idiopathic ERMs, myofibroblasts were present with increased frequency in recurrent membranes. Fibrocytes, fibrous astrocytes, and retinal pigment epithelial cells were also present in most specimens. Other features of both the primary and recurrent ERM specimens included the presence of cells with myoblastic differentiation, fragments of internal limiting membrane, new collagen, and nerve fiber elements.     

Clinical course and surgical treatment of macular epiretinal membranes in young subjects

OBJECTIVE: To examine the surgical and nonsurgical visual outcomes of young subjects with idiopathic macular epiretinal membranes (ERMs). DESIGN: Retrospective observational and noncomparative interventional case series. PARTICIPANTS: Nineteen consecutive subjects (20 eyes) aged 40 years or less with an idiopathic macular ERM. METHODS: Group 1: 10 consecutive eyes were initially seen with visual acuity of 20/50 or better; 7 eyes were observed, and 3 eyes with progressive visual loss to <20/50 underwent vitrectomy and membrane peeling. Group 2: 10 consecutive eyes with presenting visual acuity of 20/60 or worse underwent vitrectomy and membrane peeling. MAIN OUTCOME MEASURES: Visual acuity, cataract formation, ERM recurrence, operative complications. RESULTS: Group 1: With no surgery, visual acuity remained stable or improved in 5 of 10 eyes (50%), with a mean follow-up of 3.7 years. Three of 10 eyes (30%) had visual loss < or =20/60 develop and underwent vitrectomy. Postoperative visual acuity improved an average of 6 lines with a mean follow-up of 17.6 months. Group 2: After vitrectomy, visual acuity improved 2 or more lines in 7 of 10 eyes (70%), with a mean improvement of 4.4 lines and mean follow-up of 29.2 months. Groups 1 and 2: Three of 13 eyes (23%) that underwent vitrectomy had recurrent ERM formation. CONCLUSIONS: Young subjects with idiopathic macular ERMs and a presenting visual acuity of 20/50 or better had a favorable visual outcome with observation. Subjects with an initial vision of 20/60 or worse, or those who had a visual decrease to < or =20/60 had significantly improved visual acuity after vitrectomy. ERM recurrence is relatively high after surgery.     

Trypan blue- and indocyanine green-assisted epiretinal membrane surgery: clinical and histopathological studies

PURPOSE: To evaluate the clinical outcome and electron microscopic findings of trypan blue (Tb) and indocyanine green (ICG) assisted epiretinal membrane (ERM) surgery. METHODS: This is a prospective consecutive noncomparative interventional case series. After pars plana vitrectomy, 0.1 ml of 0.6 mg/ml Tb solution was applied for 1 min under air for ERM staining. After ERM removal, internal limiting membrane (ILM) was further peeled after staining with 0.2 ml of 1 mg/ml ICG solution. Intraoperative specimens were sent for electron microscopy. Tb was considered useful if the edge of ERM was stained where peeling could be initiated with a clearer visualisation of the overall extent of the ERM. RESULTS: In all, 16 eyes from 16 patients were recruited. There were nine grade 1 ERMs, five grade 2 ERMs, and two grade 3 ERMs. Tb was useful in six (67%) of the nine eyes with grade 1 ERMs and in all eyes with grade 2 or 3 ERMs. The three remaining grade 1 ERMs were removed together with surrounding ILM that was stained by ICG. The mean line of improvement was 1.3 lines with the median BCVA improved from 6/12 to 6/9. All 16 eyes had symptomatic improvement and none developed ERM recurrence. No complication related to Tb or ICG was observed clinically or angiographically. Electron microscopy of the Tb-stained ERM specimens showed fragments of ILM in all specimens. CONCLUSIONS: Tb and ICG are useful intraoperatively to improve the visualisation and facilitate complete removal of ERM and ILM in macular ERM surgery.     

Measurement of activities in two different angiotensin II generating systems, chymase and angiotensin-converting enzyme, in the vitreous fluid of vitreoretinal diseases: a possible involvement of chymase in the pathogenesis of macular hole patients

PURPOSE: To investigate possible involvement of chymase and angiotensin-converting enzyme (ACE) in the pathogenesis of vitreoretinal diseases, both of which are related to the production of angiotensin II. METHODS: We measured chymase and ACE activities in the vitreous in the 54 affected eyes of 54 patients who had undergone vitreous surgery for idiopathic macular holes (MH, n = 14), proliferative diabetic retinopathy (PDR, n = 14), idiopathic epiretinal membranes (ERM, n = 13), and rhegmatogenous retinal detachment (RRD, n = 13). RESULTS: Chymase activities in the vitreous from patients with MH, PDR, ERM, and RRD were 1.87 +/- 0.53, 0.06 +/- 0.04, 0.40 +/- 0.12, and 0.08 +/- 0.03 (mean +/- SE) mU/mg protein, respectively, and ACE activities in the vitreous humor were 0.18 +/- 0.09, 0.30 +/- 0.07, 0.01 +/- 0.01, and 0.03 +/- 0.02 (mean +/- SE) mU/mg protein, respectively. Chymase activity was significantly elevated in MH among these diseases (p < 0.01, Scheffe), and ACE was significantly activated in PDR compared to ERM and RRD (p < 0.05, Scheffe). CONCLUSIONS: Our results suggest that two different angiotensin II generating systems are activated in human vitreous humor; an increased activity of chymase may play a possible role in the formation of macular holes.     

Vitreoschisis in Eales' disease: pathogenic role and significance in surgery

PURPOSE: To report the surgical anatomy of vitreoretinal adhesions as observed intraoperatively in patients undergoing vitreous surgery for complications of Eales' disease. METHODS: Eighteen consecutive male patients (18 eyes) undergoing vitrectomy for Eales' disease were studied prospectively. Intraoperative diagnosis was vitreous hemorrhage (VH) in nine cases, traction retinal detachment (TRD) in four, VH and TRD in three, and combined traction-rhegmatogenous retinal detachment in two. Epiretinal membranes (ERMs) obtained during surgery were studied using light microscopy and immunohistochemistry. RESULTS: An incomplete posterior vitreous detachment was observed in all eyes. Multifocal vitreoretinal adhesions were evident in 83.3% of eyes. The proliferation was fibrovascular in 10 eyes and fibrous in eight. A radial traction fold extending from optic disk to periphery was observed in three eyes. A double-layered membrane, probably the result of vitreoschisis, caused tangential traction. ERMs consisted principally of type II collagen and the cellular element was predominantly composed of lymphocytes, glial cells, and macrophage-like cells (probably hyalocytes). CONCLUSIONS: Fibrous and fibrovascular proliferations have multiple areas of adhesions to the posterior vitreous cortex. The presence of type II collagen in the ERM indicates a possible vitreous collagen component to the double-layered membranes (vitreoschisis). Recognition of the double-layered membranes aids in relief of traction during surgery by delamination.