Title:Effects of Iron and Copper Overload on the Human Liver: An Ultrastructural Study
Volume: 21
Issue: 33
Author(s): D. Fanni, V. Fanos, C. Gerosa, M. Piras, A. Dessi, A. Atzei, Eyken P. Van, Y. Gibo and G. Faa
Affiliation:
关键词:
β-地中海贫血,铜过载,铁过载,肝,透射电镜,威尔逊氏病
摘要: Iron and copper ions play important roles in many physiological functions of our body, even though the exact
mechanisms regulating their absorption, distribution and excretion are not fully understood. Metal-related human pathology
may be observed in two different clinical settings: deficiency or overload. The overload in liver cells of both trace
elements leads to multiple cellular lesions. Here we report the main pathological changes observed at transmission electron
microscopy in the liver of subjects affected by Beta-thalassemia and by Wilson’s disease. The hepatic iron overload
in beta-thalassemia patients is associated with haemosiderin storage both in Kupffer cells and in the cytoplasm of hepatocytes.
Haemosiderin granules are grouped inside voluminous lysosomes, also called siderosomes. Other ultrastructural
changes are fat droplets, proliferation of the smooth endoplasmic reticulum and fibrosis. Apoptosis of hepatocytes and infiltration
of sinusoids by polymorphonucleates is also detected in beta-thalassemia. Ultrastructural changes in liver biopsies
from Wilson’s disease patients are characterized by severe mitochondrial changes, associated with an increased number
of perossisomes, cytoplasmic lipid droplets and the presence of lipolysosomes, characteristic cytoplasmic bodies
formed by lipid vacuoles surrounded by electron-dense lysosomes. In patients affected by Wilson’s disease, nuclei are
frequently involved, with disorganization of the nucleoplasm and with glycogen inclusions. On the contrary, no significant
changes are detected in Kupffer cells. Our data show that iron and copper, even though are both transition metals, are responsible
of different pathological changes at ultrastructural level. In particular, copper overload is associated with mitochondrial
damage, whereas iron overload only rarely may cause severe mitochondrial changes. These differences underlay
the need for further studies in which biochemical analyses should be associated with ultrastructural data, in order to better
understand the molecular ways associated with iron- and copper-related pathology at subcellular level.