[Treatment of Retinal Vein Occlusion - Is There Still a Role for Vitreoretinal Surgery?] / Behandlung des retinalen Venenverschlusses ­ Welche Rolle spielt die Vitrektomie heute noch?

Surgical manoeuvres for the treatment of retinal vein occlusion peaked at the turn of the century. The first overwhelming reports could not be confirmed in prospective studies. Furthermore, the functional success was never comparable to intravitreal drug therapy, and the manoeuvres are no longer used in clinical routine. The procedures, the surgical theory and the criticism on vitrectomy, radial optic neurotomy (RON), retinal endovascular fibrinolysis (REVL) and arteriovenous dissection (AVD) will be discussed in this paper. Surgical manoeuvres for the treatment of retinal vein occlusion had a peak by the end of the last and the beginning of the present century. The first overwhelming reports could not be confirmed in prospective studies. Furthermore, the functional success was never comparable to the intravitreal drug therapy and the manoeuvres are no longer used in clinical routine. The procedures, the surgical theory and the criticism on vitrectomy, radial optic neurotomy (RON), retinal endovascular fibrinolysis (REVL), and arteriovenous dissection (AVD) will be discussed in this paper.

Endogenous endophthalmitis: microorganisms, disposition and prognosis.

PURPOSE: Endogenous endophthalmitis is a severe and potentially blinding complication caused by haematogenous spreading of microorganisms. We evaluated the causative microorganisms, disposition to and prognosis of the disease. METHODS: Thirty-one eyes of 28 patients were treated between 1996 and 2006 as the result of an endogenous endophthalmitis. RESULTS: The microorganisms responsible for infection could be identified in 94% of all eyes investigated. Candida isolates were obtained in 15, gram-positive isolates in 11, gram-negative in one and Aspergillus in two of the 29 eyes studied. The majority of patients suffered from severe general disease (immuno-deficiency, severe surgical procedures, diabetes mellitus) and one third were intravenous drug abusers. Only one patient was otherwise healthy. The prognosis depended on the causative microorganisms. Whereas none of the eyes with Candida infection became blind, all except two of the eyes with gram-positive bacteria, Nocardia or Aspergillus infection lost visual function or had to be enucleated. CONCLUSION: Compared to postoperative endophthalmitis, patients with endogenous endophthalmitis are more likely to have Candida isolates. Visual prognosis depends mainly on the underlying microorganisms, and is particularly poor in the case of infection with gram-positive bacteria or Aspergillus.

Ca2+ channels in retinal pigment epithelial cells regulate vascular endothelial growth factor secretion rates in health and disease.

PURPOSE: Choroidal neovascularization (CNV) is the most severe complication in age-related macular degeneration. The major angiogenic factor involved is vascular endothelial growth factor (VEGF) secreted by the retinal pigment epithelium (RPE). Since RPE cells express neuroendocrine L-type Ca2+ channels we investigated their involvement in VEGF secretion in normal RPE cells and RPE cells from patients with CNV. METHODS: Freshly isolated and cultured RPE cells were studied using the patch-clamp technique and ELISA-based secretion assays. RESULTS: Both freshly isolated and cultured cells showed whole-cell Ba2+ currents with properties of L-type Ca2+ currents: high activation threshold, sensitivity to dihydropyridines (10 muM nifedipine) and slow inactivation. VEGF-A secretion was elevated by BayK8644 (10 microM) or basic fibroblast growth factor (bFGF, 10 ng/ml), both of which are able to activate L-type channels. Cells from CNV tissue also showed nifedipine-sensitive Ba2+ currents, which displayed a voltage-dependent activation at more negative potentials, faster inactivation and changed regulation by tyrosine kinase pp60(c-src). The CNV RPE cells showed higher VEGF secretion rates which were reduced by nifedipine. CONCLUSIONS: Thus, L-type Ca2+ channels in normal RPE cells regulate the secretion of VEGF. RPE cells from eyes with CNV maintain a VEGF secretion regulated by nifedipine-sensitve Ca2+ channels which might be of importance for the development of CNV.

Angiographic findings in arteriovenous dissection (sheathotomy) for decompression of branch retinal vein occlusion.

BACKGROUND: Arteriovenous dissection (sheathotomy) is a new therapeutic option in patients with branch retinal vein occlusion (BRVO) and macular involvement. We present an angiographic follow-up of 22 patients who underwent arteriovenous dissection (AVD). METHODS: Twenty-two patients (15 women; mean age 68.7+/-8.0 years) were examined preoperatively and 6 weeks, 3 months, 6 months, and 1 year after AVD. For assessment of retinal hemodynamics, arteriovenous passage time (AVP) of the affected and unaffected branches at first (AVPe) and at maximal (AVPmax) venous filling were measured. Changes in the foveal avascular zone (FAZ) were calculated to determine foveal structural changes. Visual acuity was assessed as functional parameter. RESULTS: The early AVP (AVPe) of the affected branch increased from 4.4+/-0.8 s preoperatively to 4.9+/-0.6 s 6 weeks after surgery and decreased to 2.7+/-0.4 s 1 year after surgery (p=0.05). When compared to the unaffected control branch, AVPe was significantly increased in the affected branch preoperatively (4.5+/-0.8 s versus 1.5+/-0.2 s, p<0.01), 6 weeks (4.9+/-0.6 s versus 2.1+/-0.3 s, p<0.01), 3 months (2.7+/-0.4 s versus 1.5+/-0.2 s, p<0.01), and 6 months (3.1+/-0.4 s versus 2.2+/-0.3 s, p=0.02) after AVD. After 1 year, AVPe no longer differed between the affected and the control branch (2.7+/-0.4 s versus 2.6+/- 0.3 s). AVPmax was significantly increased in the affected branch preoperatively (11.8+/-0.8 s versus 7.7+/-1.0 s, p<0.05). The AVPmax in the affected branch with the exception of 3 months after surgery (10.2+/-1.1 s, p<0.01) was no longer elevated when compared to preoperative values. The area of the FAZ did not change significantly but showed a trend for enlargement. CONCLUSION: AVD for decompression of BRVO leads to a significant decrease of AVP and may ameliorate retinal perfusion in the affected branch.

Cultivation of retinal pigment epithelial cells from human choroidal neovascular membranes in age related macular degeneration.

A method is described for cultivating retinal pigment epithelial cells from choroidal neovascular membrane (CNV) specimens that were surgically removed in patients with age-related macular degeneration (AMD). CNV specimens of 43 patients were available for cultivation. They were incubated in supplemented DMEM/Ham's F12 cell culture medium on microporous semipermeable filter membranes. Thirty-four specimens gave rise to cell cultures, 28 of which could be subcultivated for up to 15 passages. The membrane type as classified by fluorescence angiography was compared with cellular growth in vitro. Immunocytochemistry revealed a uniform expression of cytokeratin 18 and vimentin, while factor 8, glial fibrillary acidic protein and alpha smooth muscle actin were absent in all 21 cultures stained. The expression of RPE markers cellular retinaldehyde binding protein (CRALBP) and RPE65 was detected by RT-PCR in all cultures tested. An epithelial character of the cultures was supported by the presence of apical microvilli as determined by electron microscopical studies. Therefore, the cell cultures from CNV in AMD bear characteristics of retinal pigment epithelial cells. For the first time, this cell culture system holds the potential to study human RPE cells in the context of neovascular AMD in vitro.