Abstract
Purpose: :
Autologous platelet rich plasma (PRP) is widely accepted as adjuvant in macular hole surgery. Little is known about the cellular influence of platelets on retinal tissue, as well as about specification of appliance. The aim of this study was to find out whether anatomic and visual outcome after surgery depend on features of the administered PRP, and to investigate the activation status and growth factor release of PRP.
Methods: :
Pars plana vitrectomy (PPV) with membrane peeling and application of PRP for full–thickness macular hole was performed in 45 eyes of 45 consecutive patients by the same surgeon. Most cases were stage 4 holes (36) and had a long preclinical history (mean 7,2 mo). At surgery, cell count, pH and aggregation of PRP were determined. At mean follow–up of 42 d and 10 mo hole closure and visual acuity were recorded. To study the influence of PRP storage time between preparation and surgery on growth factor release, PDGF was measured by ELISA in PRP supernatant with and without ristocitin–stimulation 1–5 h after PRP–preparation as a mark of activation. FACS analysis was used to assess antibody–stained CD62P on thrombin–activated PRP.
Results: :
Anatomic closure was achieved in 35 cases (78%) after primary surgery. Best–corrected visual acuity improved from a mean of 0.178 to 0.200. Visual acuity improved 2 lines in 15 of 45 patients (33%). PRP of patients in whom an initial closure of the macular hole could not be achieved, showed a significantly higher ristocitin–induced platelet aggregation (p<0.01). Ristocitin stimulated PDGF–concentration in PRP was significantly higher 2–4 h after preparation (p<0.05) compared to untreated PRP. Thrombin–activated PRP showed slightly higher CD62P–expression than native PRP without reaching significance.
Conclusions: :
PPV in combination with membrane peeling and PRP instillation proves to be an adequate therapeutic option even in cases of long–term or advanced macular hole. A correlation between storage time of PRP and surgical success could not be shown. PRP from patients who did not experience hole closure displayed a significantly higher aggregation. The results point out that the positive effect seems to be due to factors released by PRP rather than a mechanical support of macular hole closure.
Keywords: macular holes • retina • growth factors/growth factor receptors