Kidney Transplant/Disease

Minimal Change Disease (MCD) is a condition where severe protein loss from kidneys occurs, resulting in very low protein levels in blood, leading to body swelling, difficulty breathing and blood clots. This collection of symptoms and laboratory findings is called The Nephrotic Syndrome, of which MCD is responsible for up to 90% of cases in children and up to 20% of cases in adults.

The cause of MCD remains unclear but our current understanding is that it might be caused by damage to the kidney by proteins of the immune system which are present in the blood. Some patients have specific antibodies in their blood which may have a role in starting the disease as the same antibodies often disappear when patients get better.

Our current treatment is to switch off the immune system and this often helps. The problem with this is that it can lead to infections and other side effects such as weight gain and diabetes.

My aim is to identify changes in the immune proteins in the blood in MCD and to look at how specific antibodies change during the illness. I have a collection of blood samples with detailed clinical information from MCD patients attending one of Europe’s largest MCD clinics. I will measure 250 proteins relating to the immune system using a very sensitive protein-measuring system (NULISA, Alamar Biosciences) and I will set up the test to measure the disease-associated antibodies (Anti-nephrin antibodies). Once I identify changes I will perform experiments to try to understand how these proteins cause kidney damage and result in a protein leak from the kidneys. Using these methods I want to identify new and more precise treatments which will be effective at restoring kidney function and not be accompanied by unpleasant side effects

Update: The measurement of the 250 proteins relating to the immune system using a very sensitive protein-measuring system has been completed and the data is being analysed. Measurement of anti-nephrin antibodies is in progress. Using clinical analysis of treatment responses in the MCD cohort I have a manuscript in progress describing the long-term outcomes of a re-purposed immunosuppressant drug called Tacrolimus in this condition.

Glomerulonephritis is inflammation of the units in the kidney that filter blood into urine, which are called glomeruli (each one is called a glomerulus). There are many causes and types of glomerulonephritis. These are identified by taking a kidney biopsy (a tiny sample of kidney tissue taken for analysis). Because of key research advances which now need to be moved into the clinic to help patients this project focuses on membranous glomerulonephritis (MN) and glomerulonephritis caused by complement (a group of proteins that are important in fighting bacteria),

The first advance is the discovery of new types of MN. MN is caused by the deposit of big clumps of protein in the glomerulus. Each case of MN is caused by the deposit of a single type of protein. Several different proteins have now been found in MN and are linked with different underlying causes, such as cancer or drugs.  Most pathology laboratories (these test tissue samples) in the UK only test for one of these proteins in kidney biopsies. This project aims to extend our ability to test for 3 new proteins. This will enable us to identify 4 types of MN rather than just one. This is important because the type of MN helps the doctor to identify the underlying cause and plan treatment. When we achieve this, we will have a state-of-the-art ability to recognise the cause of MN in our patients.

The second advance is the importance of complement in causing kidney damage. Sometimes complement can inappropriately cause damage to the kidney. There are many new drugs which switch off complement (called complement inhibitors) and these are being tested in clinical trials in patients with kidney disease.  Consequently, there is a need to expand the tests performed in our kidney pathology laboratory so we can provide as much information about complement activity within kidney biopsies to enable us to identify patients suitable for complement inhibitor treatment. This project aims to develop the ability to test for a number of different complement proteins in the kidney biopsy.

Update: The first part of our study focused on optimisation of antibody staining. This is the method we use to identify MN and complement proteins in the kidney biopsy. For MN we have optimised the staining for two proteins: exostosin-1 and THSD7a and a third, NELL-1, is in progress. Complement protein staining panels have been optimised and are now being prepared for automation on Leica Bond machines. The second part of our study is to look at the staining patterns in disease cohorts. We have identified 80 biopsies with MN and are preparing cohorts of IgA nephropathy and C3 glomerulopathy for the complement staining characterisation. The final part of the project will be to develop the business case for introducing these assays into the routine diagnostic pathology service

Kidney transplant is the treatment for end stage kidney failure with the best patient outcomes, but the life span of the transplanted kidney can be limited by the immune system causing rejection. The best way known for diagnosis of rejection is examination of a biopsy of the kidney using a microscope, but this has limitations, related to the fact only abnormalities that result in a change of appearance visible down a microscope can be seen, and related to variation in scoring of these microscopic differences between pathologists. Analysis of which genes are switched on and off during rejection in biopsies has improved our understanding of rejection. To date this has been done by mashing up a piece of the biopsy, which mixes up all the genes from all the cells in the sample, with loss of information about what happens in each cell or in each compartment of the kidney.

In contrast, in this project, we will use a new technique called “spatial transcriptomics”, which keeps the structure of the biopsy intact rather than mashing it up, so that we can see exactly which cells in the biopsy are turning on or off which genes. Knowing which cell is responsible for which changes in gene expression will lead to better understanding of rejection, and identification of new cell-specific targets for drug development. This could also support a switch from our current standard of microscopy diagnosis to a more precise diagnosis based on measurement of changes in gene expression in specific cells, which would enable selection of patients for specific drugs targeting those changes in gene expression. This more targeted management could improve health outcomes for patients. The study may also potentially lead to new treatments.

To carry out the project, we will examine biopsy samples from the archives with tissue left over after routine diagnostic tests are complete and apply spatial transcriptomics to them. No new samples will be taken from patients and the results of the study will have no impact on the patients whose samples were used for research.

Update: The samples for this project have been carefully selected to represent the full spectrum of the disease being investigated, retrieved from archives and checked for quality. Because a new, more advanced but similar technique has become available at Imperial College since our application, we have adapted our project to make use of this technique instead (CosMx instead of GeoMx). Reagents have been ordered and are in our laboratory. The date for running the samples on CosMX is booked for October 2024.