Potential Effects of Angiogenesis-related Factors on the Severity of APAC and Surgical Outcomes of Trabeculectomy

Abstract Background. Acute primary angle closure (APAC) caused by an abrupt closure of trabecular meshwork can develop into angle closure glaucoma due to uncontrolled IOP. Under reduced oxygen tension, hypoxia inducible transcription factors will be accumulated. EPO (erythropoietin) and PDGF (platelet derived growth factor) families are thought to be associated with angiogenesis under hypoxic condition.Methods. Concentrations of EPO, PDGF-AA, -BB, -CC and -DD collected in aqueous humor samples were measured. Before operations, correlations between target proteins and IOP were detected between APAC (acute primary angle closure) and cataract patients. Based on the post-operative follow-up, the effects of EPO and PDGF family members on the successful rate of trabeculectomy were tested. Results. The levels of EPO, PDGF-CC and -DD were significantly elevated in the APAC group compared to the cataract group. During the post-operative follow-up, EPO, PDGF-CC and -DD showed significant differences between the success and failure groups. In multivariable linear regression analyses, failed filtration surgery was more likely in APAC eyes with higher EPO level. The Kaplan-Meier survival plot suggested that the success rate in eyes with low EPO level was significantly higher than that in eyes with high EPO level.Conclusion. The levels of EPO, PDGF-CC and -DD were significantly elevated in failure group. EPO level correlated with preoperative IOP and numbers of eyedrops, and higher EPO level in aqueous humor is a risk factor for trabeculectomy failure. It can be a biomarker to estimate the severity of APAC and the success rate of surgery. The investigation of mechanism of EPO in APAC a may have potential clinical applications for the surgical treatment of APAC.