High Levels of Heat Shock Protein 47 in the Aqueous Humor of Patients with Acute Primary Angle Closure

Abstract

Introduction: Acute primary angle closure (APAC) is often characterized by acute elevation of intraocular pressure (IOP) accompanied by severe ocular and systemic symptoms. Excessive collagen accumulation, which can be caused by upregulated heat shock protein 47 (HSP47) expression, can produce scarring in rat conjunctival blebs. Meanwhile, the presence of HSP47 in human aqueous humor and its levels are yet to be determined. Methods: We examined 32 consecutive patients with APAC and 16 age-matched participants without APAC scheduled for cataract surgery who were enrolled as a control group. Aqueous humor samples were collected from all subjects at the time of surgery and compared between the subjects with and without APAC. Results: The levels of HSP47 in the aqueous humor of patients with APAC (1,210.4 ± 450.2 pg/mL) were found to be significantly increased (P = 0.001) compared with those in the control group (863.4 ± 240.0 pg/mL). Notably, the levels of HSP47 negatively correlated with the age of patients with APAC (P = 0.023). Conclusion: HSP47 was upregulated in the aqueous humor of patients with APAC and may play a role in scarring after trabeculectomy for APAC.