Diseases of flounder Platichthys flesus in Dutch coastal and estuarine waters, with particular reference to environmental stress factors. II. Liver histopathology

Abstract

Diseases of flounder Platichthys flesus in Dutchcoastal and estuarine waters, with particular reference to environmental stress factors. were diagnosed as hepatocellular carcinoma. Most of the remaining nodules were diagnosed as foci of cellular alteration, whlch are considered to be preneoplastic lesions. Routine histopathological examination of livers showing no gross pathology resulted in the identification of a range of lesions including hepatocellular adenoma, foci of cellular alteration, hydropic vacuolization of biliary epithelial cells and hepatocytes, inflammatory lesions, focal necrosis, regenerative foci, and fibrillar hepatocytes of unknown significance. In addition, indices were used to quantify the presence of storage vacuoles (glycogen and lipid) and the relative density of melanomacrophage centres. The results indicate that a small proportion of neoplasms would be missed if only livers with grossly detectable nodules were subjected to histological examination. The prevalence of foci of cellular alteration at the different sampling sites showed a good correspondence with that of neoplasms, providing support for the hypothesis that these conditions represent stages of the same process. Of the other lesions and quantitative ~ndices, only hydropic vacuolization of billary epithelia] cells had a spatial distribution similar to that of neoplasms. 11 is concluded that liver neoplasms and especially their precursor lesions in flounder are promising tools for monitoring exposure to potential carcinogens, provided that migration patterns are explicitly taken into account. Furthermore, experimental studies are needed to investigate the chemical agents responsible for the onset of these early lesions and their progression into neoplasms, and also to evaluate the contribution of other environmental and host-related factors. Liver histopathology

Hydropic vacuolation in the liver of three species of fish from the U.S. West Coast:lesion description and risk assessment associated with contaminant exposure

“…HydVac-like lesions are now being observed in other species, including white perch Morone americana (Camus & Wolke 1991) from the U.S. Atlantic Coast and flounder Platichthys flesus from Dutch coastal and estuarine waters (Vethaak & Wester 1996). In addition, we have identified HydVac in 3 other species of marine fish from the U.S. West Coast including starry flounder Platichthys stellatvs, white croaker Genyonemus lineatus, and rock sole Lepidopsetta bilineata (Stehr 1990, Stehr et al 1991.…”

Structure of and energy reserves in the liver of wild and cultured yellowtail flounder, Limanda ferruginea

“…In sexually mature flatfish species, such as European flounder (Platichthys flesus), winter flounder (Pseudopleuronectes americanus), and plaice (Pleuronectes platessa), the pancreatic tissue is more scattered throughout the liver (Timashova 1982;Ko¨hler 1990;Murchelano and Wolke 1991;March and Reisman 1995;Vethaak and Wester 1996). As in other fish, the histomorphology of the liver in sexually immature L. ferruginea causes difficulties in determining the functional liver units and in explaining the appearance of histopathological changes (Hampton et al 1985(Hampton et al , 1988Morrison 1987;Stehr et al 1988;Ko¨hler 1989;Krause and Cutts 1994;Vethaak and Wester 1996). In vivo microscopy of liver microvasculature in rainbow trout revealed a repeating pattern of alternation between afferent and efferent regions (Hinton and Lauren 1989).…”

“…The histomorphology of liver of flatfish such as winter flounder (Pseudopleuronectes americanus), European flounder (Platichthys flesus), English sole (Pleuronectes vetulus), and dab (Limanda limanda) resembles that of other teleosts (Hampton et al 1985(Hampton et al , 1988Morrison 1987;Stehr et al 1988;Ko¨hler 1989;Vethaak and Wester 1996, and references therein). The basic morphology and physiology of the liver of yellowtail flounder have not been studied to date, and sex differences in the studied species, and the potential differences between wild and cultured fish have also received little attention.…”

“…Many histological, histochemical, and enzyme cytochemical and biochemical parameters have been used to diagnose stress in the liver of marine teleosts, flatfish species in particular (e.g. Ko¨hler 1990;Carr et al 1991;Ko¨hler and Pluta 1995;Ko¨hler et al 1992Ko¨hler et al , 1998Husøy et al 1996;Vethaak and Wester 1996;Collier et al 1998;Myers et al 1998), notably, differences in the quantities of stored lipids and glycogen in the hepatocytes. Metabolism of these energy-rich storage products is variable, especially depending on water temperature, reproductive, and nutritional status, as well as age and state of health of the fish (Welsch and Storch 1973, and references therein).…”

Site-specific disease profiles in fish and their use in environmental monitoring

“…In flatfish liver, the presence of neoplasia has been classified as a direct indicator of contaminant exposure and likely represents a biological endpoint of historic exposure to chemicals that initiate and promote carcinogenic pathways (Myers et al 1990, 1994, Schiewe et al 1991, Reichert et al 1998. As a result, the presence of grossly visible and histologically confirmed liver neoplasms and other hepatic lesions involved in neoplasia has been used for many years in environmental monitoring programmes around the world (Myers et al 1987, Stein et al 1990, Vethaak & Wester 1996, Lyons et al 2004. At some offshore sites in the North Sea, liver tumour prevalence in wild flatfish has exceeded 10% in recent years , Cefas 2007, whereas prevalence in estuarine species can be significantly higher , Koehler 2004.…”