Modeling the Mechanical Parameters of Glaucoma

Glaucoma is a major eye disease characterized by a progressive loss of retinal ganglion cells (RGCs). Biomechanical forces as a result of hydrostatic pressure and strain play a role in this disease. Decreasing intraocular pressure is the only available therapy so far, but is not always effective and does not prevent blindness in many cases. There is a need for drugs that protect RGCs from dying in glaucoma; to develop these, we need valid glaucoma and drug screening models. Since in vivo models are unsuitable for screening purposes, we focus on in vitro and ex vivo models in this review. Many groups have studied pressure and strain model systems to mimic glaucoma, to investigate the molecular and cellular events leading to mechanically induced RGC death. Therefore, the focus of this review is on the different mechanical model systems used to mimic the biomechanical forces in glaucoma. Most models use either cell or tissue strain, or fluid- or gas-controlled hydrostatic pressure application and apply it to the relevant cell types such as trabecular meshwork cells, optic nerve head astrocytes, and RGCs, but also to entire eyes. New model systems are warranted to study concepts and test experimental compounds for the development of new drugs to protect vision in glaucoma patients

Polystyrene Pocket Lithography - Sculpting Plastic with Light

Tissue culture ware polystyrene is the gold standard for in vitro cell culture. While microengineering techniques can create advanced cell microenvironments in polystyrene, they require specialized equipment and reagents, which hinder their accessibility for most biological researchers. We developed and validated an economical and easily accessible method for fabricating microstructures directly in polystyrene with sizes approaching subcellular dimensions while requiring minimal processing time. The process involves deep ultraviolet irradiation through a shadow mask or ink pattern using inexpensive, handheld devices followed by selective chemical development with common reagents to generate micropatterns with depths/heights between 5-10 μm, which can be used to guide cell behavior. The remarkable straightforwardness of the process enables this class of microengineering techniques to be broadly accessible to diverse research communities. This article is protected by copyright. All rights reserved

Modelling the Mechanical Parameters of Glaucoma

Glaucoma is a major eye disease characterized by a progressive loss of retinal ganglion cells (RGCs). Biomechanical forces as a result of hydrostatic pressure and strain play a role in this disease. Decreasing intra-ocular pressure is the only available therapy so far, but is not always effective and does not prevent blindness in many cases. There is a need for drugs that protect RGCs from dying in glaucoma; to develop these we need valid glaucoma and drug screening models. Since in vivo models are unsuitable for screening purposes, we focus on in vitro and ex vivo models in this review. Many groups have studied pressure and strain model systems to mimic glaucoma, in order to investigate the molecular and cellular events leading to mechanically-induced RGC death. Therefore, the focus of this review is on the different mechanical model systems used to mimic the biomechanical forces in glaucoma. Most models use either cell or tissue strain, or fluid or gas-controlled hydrostatic pressure application and apply it to the relevant cell types such as trabecular meshwork cells, optic nerve head astrocytes, and retinal ganglion cells but also to entire eyes. New model systems are warranted in order to study concepts and test experimental compounds for the development of new drugs to protect vision in glaucoma patients

Identification of topographical architectures supporting the phenotype of rat tenocytes

Tenocytes, the main cell type of the tendon, require mechanical stimuli for their proper function. When the tenocyte environment changes due to tissue damage or by transferring tenocytes from their native environment into cell culture, the signals from the tenocyte niche are lost, leading towards a decline of phenotypic markers. It is known that micro-topographies can influence cell fate by the physical cues they provide. To identify the optimal topography-induced biomechanical niche in vitro, we seeded tenocytes on the TopoChip, a micro-topographical screening platform, and measured expression of the tendon transcription factor Scleraxis. Through machine learning algorithms, we associated elevated Scleraxis levels with topological design parameters. Fabricating micro-topographies with optimal surface characteristics on larger surfaces allowed finding an improved expression of multiple tenogenic markers. However, long-term confluent culture conditions coincided with osteogenic marker expression and the loss of morphological characteristics. In contrast, passaging tenocytes which migrated from the tendon directly on the topography resulted in prolonged elongated morphology and elevated Scleraxis levels. This research provides new insights into how micro-topographies influence tenocyte cell fate, and supports the notion that micro-topographical design can be implemented in a new generation of tissue culture platforms for supporting the phenotype of tenocytes. Statement of Significance: The challenge in controlling in vitro cell behavior lies in controlling the complex culture environment. Here, we present for the first time the use of micro-topographies as a biomechanical niche to support the phenotype of tenocytes. For this, we applied the TopoChip platform, a screening tool with 2176 unique micro-topographies for identifying feature characteristics associated with elevated Scleraxis expression, a tendon related marker. Large area fabrication of micro-topographies with favorable characteristics allowed us to find a beneficial influence on other tenogenic markers as well. Furthermore, passaging cells is more beneficial for Scleraxis marker expression and tenocyte morphology compared to confluent conditions. This study presents important insights for the understanding of tenocyte behavior in vitro, a necessary step towards tendon engineering