Bio-modulation of scaring Glaucoma Filtration Surgery using a novel application of coated magnesium

Abstract

Filtration surgery still plays a mainstream role of treatment for glaucoma. Postoperative scarring is the main cause of surgical failure. This study evaluated the biocompatibility and anti-proliferative properties of pure magnesium with three different coatings, which are hydroxyapatite (HA), dicalcium phosphate dihydrate (DCPD) and DCPD + stearic acid (SA), in a primary culture of human tenon's capsule fibroblasts (HTCFs) and in rabbit Glaucoma Filtration Surgery. Titanium and glass were used as controls in vitro , and trabeculectomy was used as control in vivo . The results show the number and shape of HTCFs seeded on different coatings showed less quantity and poor cell morphology. Each type of coated magnesium demonstrated significantly decreased metabolic activity of HTCFs. DCPD + SA showed higher cytotoxicity than the other coatings. Significant inhibition of proliferation was observed with the DCPD + SA coating. The expression of α-SMA was decreased in the cells when seeded on all of the coated magnesium disks. In vivo , no obvious adverse effects were observed after operation. No significant difference existed for any of the different samples regarding different ion concentrations in the aqueous humor. The inflammatory response in the titanium, DCPD and DCPD + SA treated eyes was more intense than in the trabeculectomy alone and HA groups. Western Blot analysis showed that collagen-1 and α-SMA expression was significantly lower in the titanium, HA, DCPD and DCPD+SA groups compared with the control. Different coatings on magnesium were able to affect the corrosive properties, which in turn, influenced the morphology and function of HTCFs. HA coated magnesium may be considered a very promising biodegradable material for the next generation of glaucoma drainage devices.