Human trabecular meshwork cell behavior is influenced by collagen scaffold pore architecture and glycosaminoglycan composition

Abstract

Glaucoma is a degenerative eye disease in which damage to the optic nerve leads to a characteristic loss of vision. The primary risk factor for glaucoma is an increased intraocular pressure that is caused by an imbalance of aqueous humor generation and subsequent drainage through the trabecular meshwork (TM) drainage system. The small size, donor tissue limitations, and high complexity of the TM make it difficult to research the relationship between the TM cells and their immediate environment. Thus, a biomaterial‐based approach may be more appropriate for research manipulations and in vitro drug development platforms. In this work, human TM (hTM) cells were cultured on various collagen scaffolds containing different glycosaminoglycans (GAGs) and different pore architectures to better understand how hTM cells respond to changes in their extracellular environment. Cellular response was measured by quantifying cellular proliferation and expression of an important extracellular matrix protein, fibronectin. The pore architecture of the scaffolds was altered using freeze‐casting technique to make both large and small pores that were aligned or with a non‐aligned random structure. The composition of the scaffolds was altered with the addition of chondroitin sulfate and/or hyaluronic acid. It was found that the hTM cells grown on large pore scaffolds proliferate more than those grown on small pores. There was an increase in the fibronectin expression with the incorporation of GAGs, and its morphology was changed by the underlying pore architecture. This work will help provide an insight into the behavior of hTM cells when introducing changes in their microenvironment.

Fundamental Biomaterial Considerations in the Development of a 3D Model Representative of Primary Open Angle Glaucoma

“…Contrasting data produced by Osmond (2020) addressed the previous downfalls in topology for the generation of TM in vitro models, with the development of composite collagen-GAG scaffolds with differing structures and compositions to further understand the effect on TM proliferation and characteristics. While this model did not discuss the presence of nano-scale features, the results reinforced the general consensus that TM cells preferentially maintained stable proliferation and characteristics on non-aligned collagen scaffolds [67]. The current research discussed not only convincingly demonstrates the potent influence that random, nanoscale extracellular features have on TM cellular expression, but the inability of standard, 2D TM monolayer cultures to faithfully recapitulate these innate TM characteristics.…”

A tissue-engineered human trabecular meshwork hydrogel for advanced glaucoma disease modeling

“…show altered behavior compared to 2D, highlighting the need for more biologically-relevant HTM model systems 68,69 . Current bioengineered models 37,[39][40][41][47][48][49]51,70 are useful tools for investigating aspects of HTM cell/tissue behavior under normal and simulated glaucomatous conditions, and complement proven ex vivo perfusion-cultured anterior segments and in vivo animal models. However, they cannot accurately mimic the complex native HTM cell-ECM interface, which makes them less than ideal to investigate the processes involved in the onset and progression of glaucomatous HTM stiffening typically observed with POAG.…”

“…Dynamic interactions between HTM cells and their surrounding ECM resulted in hydrogel condensation/contraction and remodeling, mimicking critical normal tissue behavior. As such, our HTM cell-encapsulated hydrogel containing (by weight) ~68% collagen type I, ~26% ELP, and ~5% HA is the first of its kind with distinct biomimetic advantages over other HTM model systems 37,[39][40][41][47][48][49]51,70 .…”

Glaucoma in mucopolysaccharidoses

“…Proliferation and fibronectin expression of TM cells were affected by pore size, alignment and composition of GAGs. This work provided insight into how the architecture and composition of collagen-GAGs scaffolds affected TM cells behavior [35].…”