Standardized Protocols for Plasma Clearance of Iohexol are not Appropriate for Determination of Glomerular Filtration Rates in Anesthetized California Sea Lions (Zalophus californianus)

Abstract

Plasma clearance of iohexol was evaluated in eight anesthetized California sea lions (Zalophus californianus), without evidence of renal dysfunction, to determine if the one-compartment model and the sample protocol used in dogs and cats could be applied to this species. Nonlinearity between samples in 75% (6/8) of sea lions voided those results. An additional two anesthetized sea lions were sampled at 5, 30, 45, 60, 120, 180, 240, and 360 min post iohexol injection and semi-logarithmic curves calculated. Plasma iohexol clearance values calculated by one-, two-, and noncompartment models were in poor agreement, suggesting that the standardized protocol described for dogs and cats cannot simply be applied to California sea lions, probably due to the effects of the dive reflex induced during anesthesia.

Proteomic Analysis of Urine from California Sea Lions (Zalophus californianus): A Resource for Urinary Biomarker Discovery

“…Furthermore, reference ranges based on age class and body mass can be difficult to validate with traditional renal clearance techniques, especially when sea lions undergo peripheral vasoconstriction in response to anesthesia. 14 Assessment of renal injury using urine protein markers has been widely described for domestic dogs, cats, livestock and humans, 15,16 with markers including urinary total protein, albumin, immunoglobulins, as well as more novel markers of tubular injury such as neutrophil gelatinase-associated lipocalin (NGAL; approved name lipocalin 2; approved symbol LCN2). Few urine protein markers studies have been conducted for the assessment of Leptospira-associated kidney disease.…”

“…Serum creatinine changes can often lag behind renal injury by up to 48 h and in the chronic setting, secretion of creatinine or reduction in creatinine production can lead to the overestimation of renal function. − Additionally, assessment of kidney damage in surveys of sea lions with no clinical history complicates diagnosis of mild renal injury because markers such as creatinine can vary with feeding status, hydration status, muscle mass, and assay bias in the presence of confounders such as bilirubin (as reviewed in ref ). Furthermore, reference ranges based on age class and body mass can be difficult to validate with traditional renal clearance techniques, especially when sea lions undergo peripheral vasoconstriction in response to anesthesia …”

Proteomic Analysis of Urine from California Sea Lions (Zalophus californianus): a Resource for Urinary Biomarker Discovery

“…Furthermore, reference ranges based on age class and body mass can be difficult to validate with traditional renal clearance techniques, especially when sea lions undergo peripheral vasoconstriction in response to anesthesia 14 .…”