Submitted to: Frontiers in Endocrinology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 11, 2013
Publication Date: October 1, 2013
Citation: Eberle, K., Waters, T.E., Jensen, E.D., Venn-Watson, S., Sacco, R.E. 2013. Development and application of specific cytokine assays in tissue samples from a bottlenose dolphin with hyperinsulinemia. Frontiers in Endocrinology. 4:134. DOI: 10.3389/fendo.2013.00134. Interpretive Summary: The present paper involves a case of an Atlantic bottlenose dolphin with a clinical history of high liver enzymes, serum iron, insulin, and cholesterol. The clinical history of this animal has been included. We have developed tests to detect specific proteins in bottlenose dolphins and applied these tests in this particular case animal. This study represents the first report of the expression of these proteins in the liver and spleen of an Atlantic bottlenose dolphin.
Technical Abstract: Chronic inflammation has been associated with insulin resistance and type 2 diabetes in humans. Postmortem hepatic and splenic tissue from a 46-year old geriatric male bottlenose dolphin (Tursiops truncatus) with insulin resistance (chronic hyperinsulinemia with hyperglycemia) , chronic = inflammation (white blood cell count greater than 12,000 cells/ul); and mild fatty liver disease was evaluated for elevated pro-inflammatory mediators. Cytokine mRNA expression in postmortem hepatic and splenic tissue, as determined by real-time PCR, included an array of cytokines: TGF-ß, TNF-a, IFN-', IL-2, IL-4, IL-10, IL-12p40, IL-13, and IL-18. Fluorescent immunohistochemistry (IHC) utilized the following antibodies: anti-porcine IL-6, anti-bovine IFN-', IL-4, and IL-10, anti-human TGF-ß, and anti-dolphin IL-8 and TNF-a. Values from this dolphin were compared to a younger reference dolphin with no known chronic metabolic perturbations or inflammation. Levels of TGF-ß,TNF-a, and IL-4were higher in the case dolphin's liver compared to that of the reference dolphin. In the case dolphin's spleen, IL-10 and IFN-' mRNA was upregulated while IL-4 was less than reference dolphin.. IL-18 and IL-13 were upregulated in both tissues. IHC in spleen from the case dolphin revealed staining of IL-4, IL-6, IL-8, and TGF-ß throughout the tissue. IL-10 and IFN-' were seen to predominate in areas surrounding the follicles of splenic tissue. This is the first characterization of cytokine levels in dolphin hepatic and splenic tissue. While there are limitations to a case study, this report of inflammatory biomarkers in tissues of a dolphin with insulin resistance and fatty liver disease are similar to those observed in human patients.