Assessment of Increased Serum Aminotransferases in a Managed Atlantic Bottlenose Dolphin (Tursiops Truncatus) Population

Abstract

ABSTRACT:Nonspecific chronic hepatitis and increased activities of serum aminotransferases have been reported in cetaceans (dolphins, porpoises, and whales). We identified bottlenose dolphins in our current population with episodic increases in serum aminotransferases, specifically alanine aminotransferase (ALT) and aspartate aminotransferase (AST), and we hypothesized that hematologic and serum biochemical changes in these animals may provide clues as to potential causes of liver disease in cetaceans. A retrospective case-control study involving 1,288 blood samples collected during 1998-2006 from 18 dolphins (six cases and 12 age-and sex-matched healthy controls) was conducted to compare eosinophil and platelet counts; and serum proteins, albumin, globulins, bilirubin, gamma glutamyltransferase (GGT), cholesterol, triglycerides, glucose, iron, and erythrocyte sedimentation rates. Bottlenose dolphins with increased ALT and AST activities were more likely to have higher serum globulins, bilirubin, GGT, iron, glucose, triglycerides, and cholesterol levels, greater erythrocyte sedimentation rates, and lower platelet counts compared to healthy controls. Our findings suggest that dolphins with chronic increases in aminotransferases may have a chronic hepatitis involving iron overload with similar etiologies and pathophysiology compared to terrestrial mammals. Areas for future research include predisposing metabolic risk factors; associations between iron overload and a diabetes-like condition; and a potential overlap syndrome involving autoimmune responses that may or may not be associated with viral infection.

Ratiometric Measurements of Adiponectin by Mass Spectrometry in Bottlenose Dolphins (Tursiops truncatus) with Iron Overload Reveal an Association with Insulin Resistance and Glucagon

“…The study included four dolphins with iron overload (cases) and five controls. Iron overload cases in this study were previously reported to have chronically elevated serum aminotransferases, specifically alanine aminotransferase (ALT) and aspartate aminotransferase (AST), as well as elevated serum iron (20). These four case animals had since undergone phlebotomy treatments in order to manage iron overload, and diagnoses of iron overload have been confirmed by live liver biopsies in three of the four animals (21).…”

Hematologic and biochemical differences between two free ranging Yangtze finless porpoise populations: The implications of habitat

“…These causes may occur in succession or concurrently [ 57 ] elevating serum ALT and AST levels [ 58 ]. Venn-Watson et al (2008) reported an episodic increase in serum ALT and AST over a 9 year period, which was later identified as chronic hepatitis with excessive iron deposition [ 59 ]. Like our study, Venn-Watson et al (2008) further reported an episodic increase in AST and ALT with higher serum cholesterol (observed), and GGT, suggesting steatosis [ 59 , 60 ] and cholestasis including, autoimmune hepatitis, sclerosing cholangitis and primary biliary cirrhosis [ 61 , 62 ].…”

Use of phlebotomy treatment in Atlantic bottlenose dolphins with iron overload

“…The cause of iron overload in dolphins is likely multifactorial and may include genetic, nutritional, and also infectious disease processes. 2 Although hereditary hemochromatosis in humans causes a primary iron overload disorder that may lead to liver damage, secondary iron overload can be a result of primary disorders of the liver and other factors such as viral hepatitis, ineffective erythropoiesis, and alcohol consumption. 30 Regardless of the cause, excess stores of iron can result in clinical abnormalities that can be resolved with the removal of iron via phlebotomy treatment.…”