New study shows glomerular ultrastructural changes in diabetic cats for first time

11 June 2025

A new study has found that cats with diabetes mellitus may develop glomerular ultrastructural changes consistent with diabetic nephropathy.

Diabetic nephropathy, also known as diabetic kidney disease, is a known complication of diabetes mellitus in humans, but to date, there has been little research on the development of diabetic nephropathy in cats.

A new study, funded by BSAVA PetSavers and the Biotechnology and Biological Sciences Research Council, and published in the Journal of Small Animal Practice, is the first to investigate the ultrastructural changes associated with diabetic nephropathy and quantify glomerular vascular endothelial growth factor -A (VEGF-A) expression in cats with diabetes mellitus.

Kidney samples were collected at post-mortem examination, from cats with and without a clinical diagnosis of diabetes mellitus. Glomerular ultrastructural changes, including glomerular endothelial cell fenestration density and width, and glomerular basement membrane, were assessed in four diabetic and five control cats, using transmission electron microscopy. Glomerular VEGF-A expression was determined in eight diabetic and five control cats, using immunohistochemistry.

The research found, for the first time, that ultrastructural changes may develop in the glomeruli of diabetic cats, consistent with diabetic nephropathy. In diabetic cats, glomerular basement membrane width was significantly increased and there was a loss of glomerular endothelial cell fenestrations, compared to control cats. Diabetic cats also had increased glomerular VEGF-A expression, similar to diabetic nephropathy in other species. Despite similar renal histopathological scores between control and diabetic cats, ultrastructural changes in the glomeruli of diabetic cats were present. This highlights the need for electron microscopy for fully evaluating renal changes in diabetic nephropathy.

As diabetic nephropathy may contribute to decreased glomerular filtering capacity and proteinuria, monitoring and treating proteinuria should form an important part of diabetic monitoring.

Dr Holly Reyes-Hughes, lead author of the study, said: “This is exciting and novel data that challenges the paradigm that cats with diabetes do not develop diabetic nephropathy, and highlights the importance of monitoring renal function and development of proteinuria in diabetic cats.”

Read the full study here: https://onlinelibrary.wiley.com/doi/10.1111/jsap.13884

The study was part-funded by BSAVA PetSavers, the grant awarding arm of the British Small Animal Veterinary Association. It has invested more than £2.7 million in vital clinical research and training programmes over the past 50 years to advance clinical investigations into pet animal medicine and surgery. For further information visit: http://www.bsava.com/petsavers