Investigation of the role of Nox and reactive oxygen species in the pathogenesis of cardiovascular and metabolic disorders/diseases and their treatment
Key Words:
NADPH oxidase; oxidative stress; cardiovascular diseases; insulin resistance; diabetes
Purpose:
Basic research, translation and applied research
Objectives:
Cardiovascular disease is a major cause of death and illness in people after middle-age and in people with obesity and diabetes. Novel therapeutic targets to treat these diseases are urgently needed to save lives and to improve our life expectance at older age.
The cells in our body generate reactive oxygen species (ROS) as products of their metabolism. Under normal physiological conditions, the amount of ROS produced by cells is tightly controlled and eliminated quickly from our body. However, when the cells face challenge or in a diseased environment, they generate too much ROS (oxidative stress) that cause damage and cell death. Discovery of the major sources of ROS generation under diseased conditions is crucial for the development of new therapies. Recently, an ROS-generating enzyme called NADPH oxidase has been found to be involved in the oxidative damage of blood vessels and the heart, and in the development of metabolic diseases. Therefore, the overall objective of this project is to discover the mechanism of NADPH oxidase activation and to test NADPH oxidase inhibitors for the purpose to treat oxidative stress-related cardiovascular and metabolic diseases.
Benefits:
This project is to discover how the ROS are generated by the NADPH oxidase in cardiovascular and metabolic diseases, which cause damage to our health. The ultimate goal is to treat oxidative stress-related human cardiovascular and metabolic diseases. The information from this project will contribute and advance our understanding of the role of NADPH oxidase in the development of cardiovascular diseases. The NADPH oxidase inhibitors have great potential for the development of novel therapies for human diseases and will benefit our life and society.
Animals used:
We are proposing to use rodents (mainly mice) for this research project. Approximately 2500 animal are budgeted over the 5 year duration of this project.
Although there are adverse effects such as high blood pressure, obesity and insulin resistance associated with this animal model of human disease, inhibiting reactive oxygen species production is expected to provide protection to animals from oxidative damage and reduce symptoms of cardiovascular and metabolic diseases.
The expected level of severity is mild or moderate. At the end of experiments, animals will be euthanised humanely and organs will be collected for biochemical and path-histological examinations.
Replacement:
Alternative ways (such as cell culture, computer modelling and organ functional assessment) have been carefully considered and used wherever possible. However, ROS metabolism is a complex process that requires integrated actions of many organs/tissues and hormones in a living animal or human. It is not possible to study or to inhibit ROS generation in the cardiovascular system without using living animals. This is currently the only way to achieve this project.
Reduction:
Studies will be designed using statistical modelling where appropriate, to minimise the number of animals required while yielding statistically sound results. More generally, when necessary, or appropriate, a professional statistician will be consulted to ensure experimental design is optimal and minimises the number of animals required, whilst ensuring statistical analysis can be performed adequately. Experimental design factors such as randomisation and level of replication will also be considered.
Tissues obtained from the animals will, wherever possible, be used in several sets of experiments such as for cardiac stem cell isolation (heart), for vessel function (aorta) and for bone marrow cell isolation (legs).
Refinement:
We will use mainly mice for this project. Mice deficient in Nox enzyme are available and have been used in our previous projects. These mice produce less ROS in diseased conditions, which provide protection against oxidative damage and reduce symptoms. Where the immune status of these mice makes them susceptible to bacterial infection, animals will be maintained in a clean and appropriate environment and inspected daily. If there is any sign of infection, animal will be euthanised humanely.
We encourage the use of cuff-handling technique whenever possible to minimise animal stress. For the study that requires the delivery of drugs to animals, we will choose the way to achieve the best results with the minimum pain and suffering to animals. Appropriate anaesthetics will be used for any surgical procedure, and analgesia will be given post operation, and animals will be closely inspected after operation. If there is any sign of an animal under suffering, NVS will be consulted and animal will be euthanised humanely.