Investigating a novel platform to optimize chronic glucagon agonism in the treatment of NAFLD
File(s)
Author(s)
Goncalves Lopes, Tatiana Raquel
Type
Thesis
Abstract
NAFLD impacts 30% of Western population, yet FDA-approved treatments remain elusive due to its incomplete understanding. Thus, this PhD sought to generate a minimally invasive platform to track NAFLD longitudinally and explore pre-clinical therapeutic options.
Before doing so, a secondary project was executed to provide technical training, that aimed to establish a platform for tracking tumour vascularization through intravital imaging. For that, renal carcinoma (RCC)-derived cells were transplanted into the anterior chamber of the eye (ACE) of animals with fluorescent blood vessels. This led to a platform yielding consistently sized tumours with trackable growth. However, loss of blood vessel fluorescence within tumours, likely due to Tie2 downregulation, hindered the original goal. Nevertheless, this platform could potentially be used to test anti-angiogenic/Tie2-normalizing drugs.
The platform to track NAFLD longitudinally was explored next. To do so, in vitro generated liver tissue with fluorescent lipid droplets would be transplanted into a host animal’s ACE, and NAFLD would then be induced via high-fat diet regime. It was hypothesized that changes in fat content could be tracked in the ectopic liver tissue through repeated imaging. Several approaches were investigated to generate liver tissue capable of long-term vascularization upon transplantation, which highlighted the difficulty of generating engraftable tissue. Nevertheless, final experiments showed that so-called liver buds were capable of vascularizing upon transplantation. Further optimization of intra-ocular liver buds' fat accumulation capacity is required.
Research demonstrated that glucagon analogue G108 improves hepatic fat and glycemia in obese animals; however, also leads to lean mass loss. This thesis final aim was to explore G108's NAFLD potential using the aforementioned NAFLD platform, which could not be fully validated. Nevertheless, traditional in vivo methods revealed that lowering G108 dosage in the context of a high-protein diet prevented lean mass loss, without compromising the benefits on liver fat or glucose tolerance.
Before doing so, a secondary project was executed to provide technical training, that aimed to establish a platform for tracking tumour vascularization through intravital imaging. For that, renal carcinoma (RCC)-derived cells were transplanted into the anterior chamber of the eye (ACE) of animals with fluorescent blood vessels. This led to a platform yielding consistently sized tumours with trackable growth. However, loss of blood vessel fluorescence within tumours, likely due to Tie2 downregulation, hindered the original goal. Nevertheless, this platform could potentially be used to test anti-angiogenic/Tie2-normalizing drugs.
The platform to track NAFLD longitudinally was explored next. To do so, in vitro generated liver tissue with fluorescent lipid droplets would be transplanted into a host animal’s ACE, and NAFLD would then be induced via high-fat diet regime. It was hypothesized that changes in fat content could be tracked in the ectopic liver tissue through repeated imaging. Several approaches were investigated to generate liver tissue capable of long-term vascularization upon transplantation, which highlighted the difficulty of generating engraftable tissue. Nevertheless, final experiments showed that so-called liver buds were capable of vascularizing upon transplantation. Further optimization of intra-ocular liver buds' fat accumulation capacity is required.
Research demonstrated that glucagon analogue G108 improves hepatic fat and glycemia in obese animals; however, also leads to lean mass loss. This thesis final aim was to explore G108's NAFLD potential using the aforementioned NAFLD platform, which could not be fully validated. Nevertheless, traditional in vivo methods revealed that lowering G108 dosage in the context of a high-protein diet prevented lean mass loss, without compromising the benefits on liver fat or glucose tolerance.
Version
Open Access
Date Issued
2023-08-17
Date Awarded
2024-03-01
Copyright Statement
Creative Commons Attribution NonCommercial Licence
License URL
Advisor
Owen, Bryn
Salem, Victoria
Publisher Department
Department of Metabolism, Digestion and Reproduction
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)