A disposable system for rapid purification of autologous plasmin as an adjunct to vitrectomy — performance and safety profile

Abstract

The isolation system generated plasmin with a high degree of purity. A failure-mode analysis did not reveal significant risks of toxicity. A single preparation can provide a maximum dose of 10.9 IU/200 μl, the likely target clinical dose being 1.88 IU. Plasmin doses of at least 12.7 IU appear be safe when injected into rabbit eyes, followed by vitrectomy.

Plasminogen purification from serum through affinity membranes

“…In particular, all eluted fraction revealed a weak band between 75 kDa and 100 kDa corresponding to plasminogen. Another band between 50 kDa and 75 kDa is compatible with both BSA (65 kDa) and the plasmin heavy chain (50 kDa) while the band present at approximately 250 kDa can be attributed to apolipoprotein B as described by Hermel et al [2].…”

“…Vitreoretinal surgery presents serious risks because mechanical peeling of the vitreous may not result in complete vitreous removal and may be traumatic to the retina [2]. Several studies [1][2][3][4] demonstrated that the limits associated with vitrectomy could be reduced by applying enzymatic vitrectomy, which allows an atraumatic vitreoretinal separation. For this reason, enzymatic vitrectomy is envisaged to augment or even replace conventional vitrectomy in view of the reduced surgical risks, surgeon time and costs [3,4].…”

“…A variety of macular diseases, inducing traction at the vitreoretinal interface, such as macular hole, macular edema, diabetic retinopathy, macular pukers, may benefit from vitrectomy [1,2]. Vitreoretinal surgery presents serious risks because mechanical peeling of the vitreous may not result in complete vitreous removal and may be traumatic to the retina [2].…”

“…Several enzymes are suitable for the hydrolysis of the vitreousretina interface [3] and among those plasmin is the most promising because it can be isolated from the patient's serum; its activity decreases to an undetectable level within 24 h and it has the property to hydrolyze a variety of glycoproteins, including lam inin and fibronectin, which are present at vitreoretinal interface and contribute to the adhesion of vitreous to the limiting membrane [1][2][3][4]. Recently, an ocriplasmin therapeutic preparation, also known as microplasmin, obtained from recombinant Pichia pastoris, has been approved by FDA and by several European countries.…”