Researchers zoom into individual kidney filters in whole human kidneys using brightest ever X-ray Blog by Dr David Long and Daniyal Jafree, University College London
Each kidney contains around one million tiny filters called glomeruli. Working together, glomeruli remove harmful waste from the blood. Injury to glomeruli is a common feature of kidney diseases, and reduces the kidney’s ability to function, eventually requiring dialysis or transplantation.
Hospital scans such as ultrasound or CT, are performed to assess the overall structure of the kidney and to detect any major changes such as cysts or cancer. However, conventional hospital scans don’t have the detail to assess individual glomeruli. Alternatively, doctors can take biopsies from the kidney and check glomeruli under a microscope. However, as biopsies assess a tiny volume of the organ, they provide only a small snapshot, and it is difficult to know what is going on in the rest of the kidney.
Now, scientists from University College London and the European Synchrotron Research Facility (ESRF) have a solution - a 3D imaging technique which can visualise entire organs at greater detail than has ever been possible. This revolutionary technology is called Hierarchical Phase-Contrast Tomography (HiP-CT) and works by using X-rays supplied by the European Synchrotron particle accelerator in Grenoble, France. HiP-CT uses the brightest source of X-rays in the world: 100 billion times brighter than a hospital X-ray.
In a research paper published in Nature Methods, including Kidney Research UK-funded researchers, Professor David Long and his PhD student, Daniyal Jafree, the scientists were able to view the entire human kidney in 3D and then zoom down to the level of individual glomeruli. As proof of principle, the scientists used this to assess 3D features of glomeruli and provide new insights into their shape and size.
Professor Long and Mr Jafree said: “There are so many fundamental questions about the structure and function of the kidney we still don’t know the answer to. Traditionally, it has been difficult to bridge the link between individual kidney cells and tiny structures such as glomeruli with how they collectively function on the scale of the whole organ, but HiP-CT could provide a solution to this.”
In their recent paper, the researchers also studied structural defects in the lungs of patients who had died from COVID-19, demonstrating the ability of HiP-CT to detect subtle changes in disease. Next, Professor Long and Mr Jafree are continuing to work with Dr Claire Walsh and Professor Peter Lee, two of the biomedical engineering experts who are responsible for this work, to study how the structure of the whole kidney is altered by diseases. The researchers said: “HiP-CT can provide the detail of looking under the microscope, but at the scale of the whole kidney. This opens up possibilities to study what happens in kidney disease like never before.”
The work is part of an ongoing effort to create a Human Organ Atlas to better understand the structure and function of organs in health and disease. Support is provided by the Chan Zuckerberg Initiative, the ESRF, the UK-MRC and the Royal Academy of Engineering. As well as Kidney Research UK, additional support was provided by the German Centre for Lung Research, the ERC, the German Registry of COVID-19 autopsies, INSERM, University of Grenoble Alpes, the Rosetrees Trust, the Wellcome Trust, Great Ormond Street Hospital Biomedical Research Centre and the German Registry of COVID-19 Autopsies.