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Department of Veterinary Medicine

Cambridge Veterinary School

Extracellular Vesicle Research Group

Extracellular vesicles (including exosomes) are nanovesicles released by cells, which contain proteins, mRNAs and microRNAs. In non-renal contexts they have various physiological functions including inter-cellular transfer of proteins and RNA, facilitation of immune responses, and modulation of the anti-apoptotic response. Urinary extracellular vesicles are also a rich source of potential biomarkers, since their membranes are composed of apical proteins from all nephron segments and they contain nucleic acid and protein cargo from the cell of origin.

I am currently a visiting research fellow in the Karet laboratory (Cambridge Institute of Medical Research), and our laboratory has demonstrated that urinary exosomes are bactericidal (Hiemstra et al, 2014), and contain microRNAs capable of paracrine modulation of tubular membrane transporters in vitro (Gracia et al, 2017). The current focus of my research is to investigate two properties of extracellular vesicles (EVs) that are relevant to renal and urinary tract disorders, namely; the utility of EVs as a source of biomarkers of renal diseases, and the clinical significance of the bactericidal activity of urinary exosomes/EVs.

I am also interested in novel biomarkers for chronic kidney disease (CKD) in cats and urothelial cell carcinoma in dogs that might allow veterinarians to detect these diseases at an earlier stage. This would allow managemental strategies to be instituted sooner when they might be more effective, thus reducing morbidity and mortality.


Tim qualified from the University of Cambridge in 2007, and following a year working in small animal practice in west London, he undertook a PhD in the Feline Research Group at the Royal Veterinary College, London under the supervision of Professor Jonathan Elliott and Professor Harriet Syme. His research focused on feline geriatric medicine and, in particular, the effect of hyperthyroidism on renal function in cats. He received the Society for Comparative Endocrinology award for “Excellence in the Advancement in Veterinary Endocrinology” in 2011 and 2015. Tim joined the department in 2012 as Senior Clinical Training Scholar in Veterinary Clinical Pathology and subsequently became Lecturer in Clinical Pathology in September 2015 and Senior Lecturer/Associate Professor in 2019. He is a Fellow of the Royal College of Pathologists and a Diplomate of the European College of Veterinary Clinical Pathology.


Key publications: 

Google Scholar - link to all publications

Excretory-secretory products from the 'brown stomach worm', Teladorsagia circumcincta, exert antimicrobial activity during in vitro growth assays. Rooney J, Williams TL, Northcote HM, Karet Frankl FE, Price DRG, Nisbet AJ, Morphew RM, Cantacessi C. Parasites and Vectors. (2022) 15: 354.

Parasitic helminths and the host microbiome - A missing 'extracellular vesicle-sized' link?. Rooney J, Northcote HM, Williams TL, Cortes A, Cantacessi C, Morphew RM. Trends in Parasitology. (2022) 38(9): 737-747.

Size-exclusion chromatography separation reveals vesicular and non-vesicular small RNA profiles differ in cell free urine. Kartunnen J, Stewart S, Kalmar L, Grant AJ, Karet Frankl FE, Williams TL. International Journal of Molecular Sciences. (2021) 22(9): 4881.

Making urinary extracellular vesicles a clinically tractable source of biomarkers for inherited tubulopathies using a small volume precipitation method: proof of concept. Williams TL, Bastos C, Faria N, Karet Frankl FE. Journal of Nephrology. (2020) 33(2): 383-386.

Urinary exosomes contain microRNAs capable of paracrine modulation of tubular transporters in kidney. Gracia T, Wang X, Su Y, Norgett E, Williams TL, Moreno P, Micklem G, Karet Frankl FE. Scientific Reports. (2017) 7: 40601.

Effect on renal function of restoration of euthyroidism in hyperthyroid cats with iatrogenic hypothyroidism. Williams TL, Elliott J, Syme HM. Journal of Veterinary Internal Medicine (2014) 28(4): 1251-1255

Association of iatrogenic hypothyroidism with azotemia and reduced survival time in cats treated for hyperthyroidism. Williams TL, Elliott J, Syme HM.  Journal of Veterinary Internal Medicine (2010) 24(5): 1086-92.

Survival and the development of azotemia after treatment of hyperthyroid cats. Williams TL, Peak KJ, Brodbelt D, Elliott J, Syme HM.  Journal of Veterinary Internal Medicine (2010) 24(4): 863-69.

Teaching and Supervisions


I am involved in didactic teaching of 4th and 5th year undergraduate veterinary students in the Clinical Pathology, Nephrology/Urology and Dermatology modules, and I regularly give small group seminars to our sixth year rotation students. I am also the Module Organiser for the Clinical Pathology and Nephrology/Urology modules, and am the current Chair of Examiners for the Final Vet MB Part 1 examinations (4th/5th year).

I am a member of the Faculty Board for the Department of Veterinary Medicine, the Educational Quality Improvement Programme (EQIP) sub-committee and the Pastoral Support Team.

I am a fellow and Director of Studies in Veterinary Medicine (years 1-6) at Fitzwilliam College.

Research supervision: 

I am a co-supervisor to a PhD student in the Cantacessi laboratory, and I supervise a number of undergraduate and resident research projects.

Other Professional Activities

Treasurer of European College of Veterinary Clinical Pathology (ECVCP)

Member of BSAVA Scientific Committee

Chair of Cambridge Extracellular Vesicle Interest Group (CEVSIG)

External Examiner for Clinical Urology module, University College Dublin, Republic of Ireland

Dr Tim  Williams
Associate Professor in Clinical Pathology
Director of Studies in Veterinary Medicine (Fitzwilliam College)

Contact Details

Email address: 
01223 337621
Takes PhD students
Available for consultancy


Person keywords: 
Extracellular vesicles
Kidney disease
Academy of Medical Sciences
PetPlan Charitable Trust
BSAVA Petsavers
European College of Veterinary Clinical Pathology