Lumican Distribution In Endothelium And Stroma Of Donor Corneas With And Without Guttae

Guttae are extracellular matrix (ECM) protrusions starting in early stages of Fuchs endothelial corneal dystrophy (FECD). Lumican is a crucial ECM proteoglycan in the corneal stroma, vital for maintaining its transparency by regulating collagen fibril assembly and is involved in immune responses during inflammation. We investigated the spatial organization of Lumican in endothelium and stroma of guttae vs healthy corneas of human donor eyes to analyse the potential difference and anatomical-functional correlation.  

1. Netherlands Institute of Innovative Ocular Surgery, Rotterdam, The Netherlands
2. Amnitrans EyeBank Rotterdam, Rotterdam, The Netherlands

Immunohistochemistry and confocal imaging were performed on 4% paraformaldehyde fixed flat-mounted central bottoms from human donor corneas (without or with guttae) for Lumican and Neural Cell Adhesion Molecule (NCAM) as a comparable ECM fluorescent signal. 

While healthy corneas demonstrated distinct spatial patterns for Lumican expressed mainly in  intertwined web-like distribution in stroma in relation to keratocytes and NCAM, guttae corneas showed altered Lumican morphology appearing like sporadic aggregations pushing cells in endothelium. Interestingly, in 3D volume viewer of approximately 50-100 µm z-stacks, in healthy corneas, Lumican appeared as repeated parallel posterior-to-anterior cords compared to altered Lumican signal in guttae endothelium and stroma.

This study examined ECM Lumican glycoprotein distribution, revealing distinct spatial and vertical appearance across healthy corneas which is altered in cornea guttata. These findings suggest that guttae could be related to altered Lumican distribution in both endothelium and stroma.