Organohalogen concentrations and a gross and histologic ...

Figure 1
Hepatic lipid accumulation in a 16year-old
female East Greenland polar
bear (group: moderate). Arrows
indicate cites of microvesicular intracellular
fat (foamy cytoplasm),
macrovesicular intrahepatocytic cellular
fat, Ito-cell lipid accumulation
and periorientation of the nuclei
(HE, 40x).
cells, located in the space of Disse, were tested positive for haemosiderin
(iron pigments) and hepatocytes were tested positive for deposits compatible
with glycogen. In addition, nearly all individuals exhibited nuclear dislocation
from the normal, central cytoplasmic placement in parenchymal
cells (Fig. 1). In the following, each histological change is described separately.
Lipid
The majority (81%) of animals showed lipid accumulation in hepatocytes
and prominent Ito-cells of varying degree (Table 1, Fig. 1). Hepatocytic accumulation
was present as microvesicular lipid seen as foamy cytoplasm or
as sharply demarcated vacuoles, and distributed mainly centrolobularily.
Non-parenchymal lipid vacuoles of diverging size and number were found
in centroacinary pluripotent Ito-cells (i.e. stellate cells and lipocytes), located
in the narrow space of Disse and between hepatocytes, mainly in centroacinary
zones (Fig. 1). In the case of intra-hepatocytic lipid accumulation
(micro- and macrovesicularily, respectively) there was no difference among
age/sex group (p>0.3), while the degree of Ito-cell lipid accumulation was
highly different among age/sex groups (p