Intravitreal Functional Plasminogen Is Elevated in Central Retinal Vein Occlusion

Abstract

Purpose: To detect intravitreal functional plasminogen in vitreous samples of patients with recent onset of central retinal vein occlusion (CRVO) and to demonstrate significantly higher intravitreal plasminogen in CRVO patients in comparison to controls. Methods: Prospective clinical case series of 13 consecutive patients with recent onset of CRVO scheduled for core pars plana vitrectomy and 10 consecutive patients undergoing standard pars plana vitrectomy for routine macular surgery or vitreal floater removal. In all 23 cases, vitreous taps were extracted from the central vitreous body, and plasminogen was functionally determined in a new ultrasensitive p-nitroanilide reaction after activation with streptokinase (100% of normal, %N = functional plasminogen in pooled normal citrated plasma). Results: Plasminogen was detected in all analyzed samples (n = 23), and mean plasminogen was revealed to be 1.33 ± 1.73% (mean ± SD), with a range of 0.03-7.8%N. Patients with recent onset of CRVO exhibited significantly higher intravitreal plasminogen (2.19 ± 1.89%N) in comparison to controls (0.20 ± 0.21%N; p < 0.001, Mann-Whitney U test). Conclusion: Due to significantly increased intravitreal plasminogen in patients with recent onset of CRVO, intravitreally administered tissue plasminogen activator might be an option to induce posterior vitreous detachment (enzymatic vitreolysis) in CRVO patients.

Intravitreal Functional Plasminogen in Eyes with Branch Retinal Vein Occlusion

“…In concordance with previously detected significant differences in intravitreal VEGF levels in eyes with CRVO and BRVO [12], lower plasminogen activities were expected in BRVO-affected eyes. The comparison of the data provided here of intravitreal functional plasminogen of 1.35 ± 1.11%N with previously reported plasminogen values of 2.19 ± 1.89%N in CRVO-affected eyes [11] supports our hypothesis.…”

“…The detection of intravitreal functional plasminogen in eyes with CRVO (as previously reported [11]) and BRVO (as demonstrated here) using the same sampling as well as analyzing techniques supports the quality of the plasminogen assay employed, because even lower plasminogen activities in eyes with BRVO could be detected for the first time. This in turn emphasizes the potential value of this analyzing technique for further investigations of functional plasminogen in eyes with different vitreoretinal pathologies.…”

“…A recent publication demonstrated the presence of intravitreal functional plasminogen in eyes with CRVO for the first time and the activities measured therein were significantly elevated in comparison with controls without a BRB disturbance [11]. When collecting vitreous samples it is important to aspirate the specimen at the same intravitreal location.…”

“…Particular attention is needed in regard to the stabilization regimen of extracted vitreous fluid as well. Both aspects have recently been described [11] and apply to this investigation as well. In the present research project we found significantly elevated functional plasminogen in eyes suffering from BRVO (‘leaky eyes') when compared with controls without BRB disturbance [15] (‘nonleaky eyes') as well (fig.…”

“…If intravitreal plasminogen is present in BRVO-affected eyes, intravitreally applied tissue plasminogen activator (t-PA) will activate plasminogen into the active enzyme plasmin, thus facilitating PVD development [10]. It was recently demonstrated that functional plasminogen is significantly elevated in eyes with central retinal vein occlusion (CRVO) [11]. Intravitreal plasminogen activities in eyes suffering from BRVO were expected to be lower in comparison with CRVO-affected eyes in accordance with previously reported significantly different intravitreal VEGF levels in both retinal vein occlusion entities [12].…”