Award Title: Developing light sheet microscopy of murine and human gut to assess (pre)diabetic microvascular disease
Funder: The Academy of Medical Sciences

Abstract: A complex microvascular network pervades the body to regulate physiological parameters, such as metabolite delivery and oxygenation. Endothelial cells line the vasculature and form the barrier that selectively regulates these processes. Pericytes further support microvascular integrity and provide additional functional regulation.

Diabetes causes vascular injury that can lead to important complications. Perhaps best studied is diabetic retinopathy, characterised by endothelial dysfunction and pericyte apoptosis that leads to vessel regression, followed by regrowth of poor quality leaky neovessels, causing blindness. It remains unclear whether diabetes and pre-diabetic conditions like obesity cause similar vascular abnormalities throughout the rest of the body.

The intestine has a highly specialised microvascular network which has roles in nutrient absorption and immune cell regulation, and which acts as a barrier to microbial entry. Mice and humans with diabetes have a leaky gut wall, but the potential role of endothelial cells and pericytes in this disturbance is unknown.

Historically, the intestinal vasculature has proved difficult to assess due to imitations of sample preparation and image resolution. This project will optimise a novel light sheet microscopy technique to allow three-dimensional imaging of the microvascular network of the intestine in health and disease, focussing on the identification and staining of endothelial cells and pericytes within these tissue preparations, along with imaging gut wall permeability. It will then explore altered gene transcription in the gut endothelium. These data will advance our understanding about how diabetes increases gut permeability and will support my future intermediate clinical fellowship proposal.

Lay Abstract: Networks of small blood vessels transport oxygen and nutrients throughout the body. Scientists currently study these networks by cutting very thin “sections” of tissue to examine on a slide under a microscope, but this means we can only get flat 2-dimensional images. I want to use a new type of ‘light sheet’ microscope that images large tissue samples by moving a laser beam through them to study whole blood vessel networks in 3 dimensions. I will be concentrating on blood vessels in the gut as these are important in how we absorb nutrients and toxins from our diet. I want to know if diseases like diabetes and obesity are linked with abnormal gut blood vessels or with a gut wall that is more “leaky” than in the healthy state.

A particular focus will be cells called pericytes which support the structure and function of blood vessels. We know that some people with diabetes have fewer pericytes in the back of the eye and that this damages blood vessels, leading to a disease called retinopathy, which can cause blindness. Little is known about pericytes in gut blood vessel networks and whether they are abnormal in people with diabetes. This is partly because pericytes are difficult to see in 2-dimensional microscope images. I want to use our light sheet microscope to solve this problem and hope this information can tell us if treatments targeting gut blood vessels might help people with diabetes.

Research Activity Codes: 1.4 METHODOLOGIES AND MEASUREMENTS;2.5 RESEARCH DESIGN AND METHODOLOGIES (AETIOLOGY)
Health Categories: METABOLIC AND ENDOCRINE