Gaining Cellular Control of Ocular Biomechanics - A Potential Route to the Treatment of Eye Disease
Lead Research Organisation:
Cardiff University
Department Name: Sch of Engineering
Abstract
EPSRC Portfolio: The project aligns with following EPSRC 'maintain' areas: - Biomaterials & Tissue Engineering, Biophysics & Soft Matter Physics, Numerical Analysis
The sclera ('white of the eye') maintains the eye's structural integrity and stable vision. Scleral biomechanics are governed by the load-bearing extracellular matrix (ECM), with dynamic modulation by mechano-sensitive fibroblasts. While the role of the scleral ECM in determining tissue mechanics has been extensively researched, cellular contributions are less well-understood. Given scleral mechanical compromise underpins several leading causes of visual impairment [8-10], a better understanding of cellular aspects of scleral biomechanics will drive development of new treatments.
We propose dynamic scleral biomechanical behaviour is modulated by slow (ECM remodelling) and rapid (cytoskeletal-ECM) fibroblast-driven responses, critical to the eye's ability to withstand normal and pathological variations in intraocular pressure (IOP) over multiple time-scales, as evidenced in other fibroblastic cell types, including intervertebral disc, chondrocytes and osteoblasts. Our pilot studies showed mechanical loading of scleral fibroblasts stimulates cell proliferation and alters cytoskeletal organisation. We recently developed a numerical framework for cytoskeletal/ECM networks based on an integrated 3D random fibre model. The current project will extend this by incorporating experimentally-derived cytoskeletal/ECM fibre orientations to extract physiologically-accurate mechanical properties.
Aims of the project:
1. Determine contractile response of human scleral fibroblasts to IOP fluctuations by subjecting cells to oscillating strains simulating scleral wall stress in-vivo.
2. Characterise cytoskeletal protein re-organisation under simulated IOP using confocal microscopy.
3. Quantify collagen fibre organisation in scleral ECM using x-ray scattering and multiphoton microscopy.
4. Build numerical models to predict impact of pressure-regulated alterations in fibroblast force transduction on human eye biomechanics. We will adapt our random fibre models (Fig. 3) of cytoskeletal network (Aim 2 data), and integrate this with a representative ECM fibre model for the sclera (Aim 3 data).
5. Investigate effect of in-vivo pathological increases in IOP on Aim 1-4 outcomes using an experimental mouse model of glaucoma
Outcome: Scleral biomechanical compromise underpins the pathophysiology of myopia and glaucoma, vision disorders that collectively affect over 1.7 billion people. There is currently major clinical interest in developing interventions based on modification of scleral material properties. However attainment of clinical endpoints will rely on fundamental scientific understanding of scleral biomechanical function. Thus, the proposed work will inform and drive the future development of novel myopia and glaucoma therapies. Specifically, the outcomes will help identify key cell mechano-transduction pathways that can potentially be modified to control the eye's biomechanical behaviour.
The sclera ('white of the eye') maintains the eye's structural integrity and stable vision. Scleral biomechanics are governed by the load-bearing extracellular matrix (ECM), with dynamic modulation by mechano-sensitive fibroblasts. While the role of the scleral ECM in determining tissue mechanics has been extensively researched, cellular contributions are less well-understood. Given scleral mechanical compromise underpins several leading causes of visual impairment [8-10], a better understanding of cellular aspects of scleral biomechanics will drive development of new treatments.
We propose dynamic scleral biomechanical behaviour is modulated by slow (ECM remodelling) and rapid (cytoskeletal-ECM) fibroblast-driven responses, critical to the eye's ability to withstand normal and pathological variations in intraocular pressure (IOP) over multiple time-scales, as evidenced in other fibroblastic cell types, including intervertebral disc, chondrocytes and osteoblasts. Our pilot studies showed mechanical loading of scleral fibroblasts stimulates cell proliferation and alters cytoskeletal organisation. We recently developed a numerical framework for cytoskeletal/ECM networks based on an integrated 3D random fibre model. The current project will extend this by incorporating experimentally-derived cytoskeletal/ECM fibre orientations to extract physiologically-accurate mechanical properties.
Aims of the project:
1. Determine contractile response of human scleral fibroblasts to IOP fluctuations by subjecting cells to oscillating strains simulating scleral wall stress in-vivo.
2. Characterise cytoskeletal protein re-organisation under simulated IOP using confocal microscopy.
3. Quantify collagen fibre organisation in scleral ECM using x-ray scattering and multiphoton microscopy.
4. Build numerical models to predict impact of pressure-regulated alterations in fibroblast force transduction on human eye biomechanics. We will adapt our random fibre models (Fig. 3) of cytoskeletal network (Aim 2 data), and integrate this with a representative ECM fibre model for the sclera (Aim 3 data).
5. Investigate effect of in-vivo pathological increases in IOP on Aim 1-4 outcomes using an experimental mouse model of glaucoma
Outcome: Scleral biomechanical compromise underpins the pathophysiology of myopia and glaucoma, vision disorders that collectively affect over 1.7 billion people. There is currently major clinical interest in developing interventions based on modification of scleral material properties. However attainment of clinical endpoints will rely on fundamental scientific understanding of scleral biomechanical function. Thus, the proposed work will inform and drive the future development of novel myopia and glaucoma therapies. Specifically, the outcomes will help identify key cell mechano-transduction pathways that can potentially be modified to control the eye's biomechanical behaviour.
Organisations
People |
ORCID iD |
| Petar Markov (Student) |
Studentship Projects
| Project Reference | Relationship | Related To | Start | End | Student Name |
|---|---|---|---|---|---|
| EP/N509449/1 | 01/10/2016 | 30/09/2021 | |||
| 1805086 | Studentship | EP/N509449/1 | 01/10/2016 | 31/03/2020 | Petar Markov |
| Description | Determined changes in posterior scleral collagen organisation in patients with high myopia (over 6D). This is in support of the standing idea of pathological restructuring of the sclera with high myopia. These alterations could be a reason for the increased susceptibility of these patients to develop glaucoma and further complications. Developed an image analysis technique to study laser microscopy images of fibrillar structures, similar to X-ray data experiments. In combination, they provide a more holistic approach in the study of the scleral extracellular matrix, which is a key component in retaining the proper structural integrity of the eye. X-ray scattering results indicate that scleral extracellular organisation around the optic nerve is less developed in smaller animals in comparison to humans. This suggests that future studies of the ocular biomechanics should utilise larger animal eyes. In vitro results on the effects of normal (physiological) and elevated (pathological/glaucomatous) mechanical load on the cells in the sclera. Cells exposed to the physiological regime became elongated and had highly aligned cytoskeletal protein arrangement, whilst those exposed to higher load exhibited an inhibition delay in their organisation, which reverts with time. Combined several 3D image reconstruction modalities with high-resolution laser confocal microscopy to produce an approach for generating more physiologically accurate finite element models of intracellular structures. All of the listed findings are envisioned to contribute to creating complex finite element models of the ocular tissues and cells. |
| Exploitation Route | As more than 23% of the world's population suffers from myopia, with prevalence expected to reach 50% by 2050, these findings could be used for future studies of eye biomechanics. Specifically, we envision incorporating the results in more physiologically accurate finite element models, which in turn could be used in developing targetted treatments for ocular pathologies such as myopia and glaucoma. |
| Sectors | Healthcare,Pharmaceuticals and Medical Biotechnology |
| Title | Method for quantification of fibrilar structures using second harmonic generation imaging and two-dimensional discrete Fourier transform |
| Description | This approach allows for the automatic quantification of fibrillar structures recorded from laser microscopy. The software divides the input images into smaller tiles and applies a 2D Fast Fourier transform. It includes an algorithm that corrects the edge discontinuity artefact (Gibbs phenomenon) from the Fourier transform, which allows for greater accuracy and a significantly smaller loss of signal information in comparison to the standard approaching (using windowing functions). Results have been validated using corresponding X-ray scattering images, which our group has previously utilised in the study of the collagen microstructure in sclera and cornea. For further information please refer to the provided DOI for the corresponding journal article. |
| Type Of Material | Data analysis technique |
| Year Produced | 2018 |
| Provided To Others? | No |
| Impact | Using this bespoke software it was determined how the collagen fibres are organised through the depth of bovine peripapillary sclera. The image analysis was performed on multiphoton images of several sections of the sclera (data not published). (Project aim 3) It is also used in assessing the cytoskeletal protein arrangement in bovine scleral fibroblasts (data not published). (Project aim 2). As of writing, the software has not been released to the public, which restricts the general outreach. |
| Description | 25th Congress of the European Society of Biomechanics - Talk |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | Gave an oral presentation based on research from third year at the 25th Congress of the European Society of Biomechanics in Vienna, Austria. The presentation was attended by approximately 30 delegates, including lecturers, research associates and PhD students. Presentation was well liked and resulted in a discussion afterwards. |
| Year(s) Of Engagement Activity | 2019 |
| Description | CITER Network Showcase and Annual Scientific Meeting - Talk |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | Local |
| Primary Audience | Professional Practitioners |
| Results and Impact | Gave a talk on first year PhD research at the CITER (Cardiff Institute for Tissue Engineering and Repair) Annual Scientific Meeting, in Cardiff, UK. The presentation was attended by approximately 90 delegates, including lecturers, research associates and PhD students. Presentation was well liked by the other PhD students and resulted in numerous discussions afterwards. |
| Year(s) Of Engagement Activity | 2017 |
| Description | Diamond Light Source Family Open Day |
| Form Of Engagement Activity | Participation in an open day or visit at my research institution |
| Part Of Official Scheme? | No |
| Geographic Reach | Regional |
| Primary Audience | Public/other audiences |
| Results and Impact | Presented to interested families the structure of the eye and along with parts of the PhD research, specifically on the ocular pathology glaucoma. The stand included a poster of a normal and diseased eye illustrating the changes in structure and vision. Glasses that could be put on to see what people with glaucoma see were provided. A laser pointer was used to show how the light from the Diamond Light Source passes through the tissue and how we can use those results. Through a PowerPoint presentation, it was further explained what research is being performed and the goal of better studying the disease mechanics to create new treatments. The stand was visited by between 30 and 40 visitors, predominately families with children. |
| Year(s) Of Engagement Activity | 2017 |
| Description | SenSyT Symposium - Poster |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | National |
| Primary Audience | Postgraduate students |
| Results and Impact | Presented a poster based on research from second year at SenSyT Symposium organised at University College London. Poster was on display during the lunch hour break and afternoon poster session and was viewed by the majority of attendees. Discussions with delegates resulted in constructive input for future research. |
| Year(s) Of Engagement Activity | 2018 |
| Description | Speaking of Science: Interdisciplinary Conference - Poster |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | Regional |
| Primary Audience | Postgraduate students |
| Results and Impact | Presented a poster based on research from second year in the PhD student only interdisciplinary conference "Speaking of Science" in Cardiff, UK. Poster was on display in the main conference area and was viewed by probably 100 PhD students, potentially more. Discussions with delegates resulted in constructive input for future research. Poster was well liked by the audience and was awarded "People's Choice Award for Best Poster". |
| Year(s) Of Engagement Activity | 2018 |
| Description | Speaking of Science: Interdisciplinary Conference - Talk |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | Regional |
| Primary Audience | Postgraduate students |
| Results and Impact | Presented first year of research in the PhD student only interdisciplinary conference "Speaking of Science" in Cardiff, UK. The talk was attended by about 40 PhD students and resulted in a number of questions which were taken into consideration for future research and improvements. |
| Year(s) Of Engagement Activity | 2017 |
| Description | The Association for Research in Vision and Ophthalmology (ARVO) Annual Meeting - Poster |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | Presented poster based on research from third year at The Association for Research in Vision and Ophthalmology (ARVO) Annual Meeting in Vancouver, Canada. Poster was on display for a full day in the main conference area and was viewed by probably more than 100 delegates, potentially more. Discussions with delegates resulted in constructive input for future research. |
| Year(s) Of Engagement Activity | 2019 |
| Description | Vision Researchers Colloquium - Talk |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | Regional |
| Primary Audience | Professional Practitioners |
| Results and Impact | Gave a talk on first year PhD research at the Vision Researchers Colloquium, organised by the Bristol Vision Institute in collaboration with the Universities of Bath, Exeter and Cardiff, in Bath, UK. The presentation was attended by about 60 researchers, including PhD students and post-docs. The presentation resulted in several questions and discussions afterwards. |
| Year(s) Of Engagement Activity | 2017 |