ORIGINAL RESEARCH article
Front. Vet. Sci.
Sec. Veterinary Clinical, Anatomical, and Comparative Pathology
Lipid droplets in felid kidneys: prevalence and composition by lipidomics
Provisionally accepted
Rebecca Brociek1
Rebecca Alborough1
Anna Kotowska2
Ana Ferreira1Sandra Martinez-Jarquin2Malgorzata Walczak3
Frederic Beaudoin4*
David S Gardner1*- 1Veterinary Medicine, University of Nottingham, Nottingham, United Kingdom
- 2University of Nottingham School of Pharmacy, Nottingham, United Kingdom
- 3University of Nottingham School of Biosciences, Sutton Bonington, United Kingdom
- 4Rothamsted Research, Harpenden, United Kingdom
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An accepted and common phenotypic curiosity of Felidae is the presence of intracytoplasmic lipid droplets in renal proximal tubule epithelial cells (RPTEC), also frequently in urine (lipuria). Both outcomes are currently considered, and taught, as incidental – without obvious pathophysiological consequence. This contrasts markedly with clinical (human) medicine where lipid vacuoles in RPTEC are usually associated with metabolic or chronic disease, such as CKD. Despite domestic felids having a high incidence of CKD as they age, no study has fully characterised feline RPTEC lipid droplets in the context of CKD. Here, we first characterised the incidence of RPTEC lipid in domestic cat (with/without CKD or chronic interstitial nephritis) versus domestic dog and Scottish Wildcat, across a wide age range. Felids (domestic, wildcat) consistently had greater renal lipid content than dogs at all ages studied. Intracytoplasmic lipid extraction with chromatography, fatty acid characterisation and mass spectrometry-based lipidomics revealed unusual presence of a panoply of novel lipids found only in domestic cat: lipids were primarily modified (i.e. less polar) ether-soluble triacylglycerols including monoalkyldiacylglycerols (MADAGs) and other branched-chain fatty acids. We suggest common presence of such rare lipid species in tubular lipid droplets in domestic cat reflects an aspect of felid biology that parallels age-related disease prevalence, in particular, being associated with the aetiopathogenesis of chronic renal interstitial nephritis (CIN) – a hallmark of CKD in felids.
Keywords: cat, Felids, lipid droplet, lipidomics, nutrition
Received: 23 Sep 2025; Accepted: 19 Jan 2026.
Copyright: © 2026 Brociek, Alborough, Kotowska, Ferreira, Martinez-Jarquin, Walczak, Beaudoin and Gardner. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence:
Frederic Beaudoin
David S Gardner
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