Proteolytic Degradation and Inflammation Play Critical Roles in Polypoidal Choroidal Vasculopathy

Sandeep Kumar, Hiroyuki Nakashizuka, Alex Jones, Alyssia Lambert, Xuchen Zhao, Megan Shen, Mackenzie Parker, Shixian Wang, Zachary Berriochoa, Amrita Fnu, Stephanie VanBeuge, Patricia Chévez-Barrios, Mark Tso, Jon Rainier, Yingbin Fu

Research output: Contribution to journalArticle

11 Scopus citations

Abstract

Polypoidal choroidal vasculopathy (PCV) is a common subtype of wet age-related macular degeneration in Asian populations, whereas choroidal neovascularization is the typical subtype in Western populations. The cause of PCV is unknown. By comparing the phenotype of a PCV mouse model expressing protease high temperature requirement factor A1 (HTRA1) in retinal pigment epithelium with transgenic mice expressing the inactive HTRA1S328A, we showed that HTRA1-mediated degradation of elastin in choroidal vessels is critical for the development of PCV, which exhibited destructive extracellular matrix remodeling and vascular smooth muscle cell loss. Compared with weak PCV, severe PCV exhibited prominent immune complex deposition, complement activation, and infiltration of inflammatory cells, suggesting inflammation plays a key role in PCV progression. More important, we validated these findings in human PCV specimens. Intravitreal delivery of an HTRA1 inhibitor (DPMFKLboroV) was effective (36% lesion reduction; P = 0.009) in preventing PCV initiation but ineffective in treating existing lesions. Anti-inflammatory glucocorticoid was effective in preventing PCV progression but ineffective in preventing PCV initiation. These results suggest that PCV pathogenesis occurs through two stages. The initiation stage is mediated by proteolytic degradation of extracellular matrix proteins attributable to increased HTRA1 activity, whereas the progression stage is driven by inflammatory cascades. This study provides a basis for understanding the differences between PCV and choroidal neovascularization, and helps guide the design of effective therapies for PCV.

Original languageEnglish (US)
Pages (from-to)2841-2857
Number of pages17
JournalAmerican Journal of Pathology
Volume187
Issue number12
DOIs
StatePublished - Dec 2017

ASJC Scopus subject areas

  • Pathology and Forensic Medicine

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