Complex diagnostics of fatty liver dystrophy in dogs

Fatty hepatosis in dogs is a common pathological process accompanied by accumulation of lipids in hepatocytes, impairment of the liver’s metabolic functions, and the development of inflammatory and dystrophic changes, which significantly affect the clinical course of the disease and prognosis. The objectives of the study were to evaluate the activity of cytolytic (alanine- and as pa tate aminotransferase, glutamate dehydrogenase) and cholestatic (gamma-glutamyltransferase, alkaline phosphatase) enzymes, and also to determine the concentration of bile acids in blood serum of dogs of different breeds suffering fatty liver dystrophy, namely German shepherd, spaniel, Yorkshire terrier, and mixed-breed dogs. The animals underwent clinical examination, ultr a sound diagnostics, liver biopsy, histological and electronic-microscope analysis of the bioptates, and their blood was gathered for laboratory analyses. We examined 140 dogs aged two to six years, weighing 2.5 to 46 kg. In the dogs with fatty liver dystrophy, the informative diagnostic criteria were concentration of bile acids in blood serum prior to feeding and two hours later, and also the activity of hepatoindicatory cytolytic (glutamate dehydrogenase, aspartate aminotransferase, alanine aminotransferase) and cholestatic (gamma-glutamyltransferase, alkaline phosphatase) enzymes. Changes in the mentioned biochemical parameters were present in all the clinically ill dogs. We determined a high positive correlation between the concentration of bile acids prior to and two hours after feeding the dogs: German shepherds, spaniels, Yorkshire terriers, and mixed-breed dogs. In the clinically healthy German shepherds, the reference values of concentration of bile acids in blood serum before and two hours after meal measured 2.4–8.4 and 12.9–16.7 µmol/L, respectively. The concentration of bile acids in blood serum of the fatty-liver-dystrophy patients before and two hours after feeding was elevated, in particular 15.9% in the German shepherds, 33.3% in the spaniels. We also determined a strong positive correlation between the concentration of bile acids in blood serum of the ill German shepherds prior to and two hours after meal (r = 0.963). According to the ultrasound study, 100% of the dogs were observed to have uniform diffusive increase in echogenicity of the liver parenchyma. The liver contours were rounded, the vascular pattern was impov e rished, the capsule had a dense echostructure, and the structure of parenchyma was coarse-granular. As revealed by the histolog i cal and histochemical study, the liver of the German shepherds had large foci of fatty dystrophy of hepatocytes, and also fine focal spots of dystrophy on the bile ducts’ epithelium. In the liver bioptates from the German shepherds, we observed pronounced ultrastructural changes, including some hepatocytes containing average-sized lipid droplets with low electronic density and other hepatocytes having large lipoprotein inclusions. In the hepatocytes’ cytoplasm, we detected an increase in the number of pero x isomes and autophagolysosomes against the background of an expansion of the spaces of Disse. In addition, we found sludges of red blood cell and electronically dense masses of blood plasma in the lumens of blood capillaries and an expa n sion of collagen fibers between hepatocytes we observed.