Karyometry of nuclei in liver cells. Heterogeneity of nuclear volume and percentage of binucleate cells associated with veins

Albumin-expressing hepatocyte-like cells develop in the livers of immune-deficient mice that received transplants of highly purified human hematopoietic stem cells

Rodent bone marrow cells can contribute to liver. If these findings are applicable to humans, marrow stem cells could theoretically be harvested from a patient and used to repair his/her damaged liver. To explore this potential, CD34(+) or highly purified CD34(+)CD38(-)CD7(-) human hematopoietic stem cells from umbilical cord blood and bone marrow were transplanted into immunodeficient mice. One month after transplantation, carbon tetrachloride (CCl(4)) was administered into the mice to induce liver damage and hepatocyte proliferation. Mice were analyzed in comparison with CCl(4)-injured mice that did not receive transplants and noninjured controls that received transplants with the same stem cell populations, one month after liver damage. Human-specific albumin mRNA and protein were expressed in the mouse liver and human albumin was detected in the serum of mice that had received CCl(4) injury. Human alpha-fetoprotein was never expressed, but in some mice, human cytokeratin 19 was expressed, which may indicate bile duct development in addition to the albumin-secreting hepatocyte-like cells. Human albumin was not expressed in the starting stem cell populations in injured mice that did not receive transplants nor in noninjured mice that had received transplants of human stem cells. Human albumin expression was detected only in CCl(4)-treated mice that received transplants of human stem cells, and recovery was increased by administration of human hepatocyte growth factor 48 hours after the CCl(4)-mediated liver injury. Our studies provide evidence that human "hematopoietic" stem/progenitor cell populations have the capacity to respond to the injured liver microenvironment by inducing albumin expression.

Morphometric study of alterations of extrafocal hepatocytes of rat liver treated with N-nitrosomorpholine

Male Sprague-Dawley rats were treated with the hepatocarcinogen N-nitrosomorpholine for 7 weeks and observed for up to 40 weeks after withdrawal of the carcinogen. In addition to the focal preneoplastic lesions described earlier there were also alterations in extrafocal hepatocytes and these changes have been quantified morphometrically. Since the periportal and perivenous hepatocytes were not altered to the same extent, cells of the periportal zone (PPZ) and cells of the perivenous zone (PVZ) were measured separately. Immediately after stopping treatment there was marked enlargement of the hepatocellular cytoplasm and of the nuclei in both the PPZ and the PVZ and a reduction in the number of binuclear hepatocytes. While these alterations were totally reversed during the first 10 weeks after treatment ceased in the PPZ, statistically significant changes in nuclear size, nuclear-cytoplasmic ratio and number of binuclear cells persisted in the PVZ up to 40 weeks after the end of treatment. We suggest that both the foci of altered hepatocytes as well as the persisting changes in extrafocal hepatocytes may be involved in the process of hepatocarcinogenesis.

Image analysis of the histochemical demonstration of glucose-6-phosphatase activity in rat liver

Activities of histochemically demonstrated glucose-6-phosphatase were quantified by computerized densitometry using image analysis in livers of female adult Wistar rats fed ad libitum and fasted 22 h before sacrifice. Mean optical densities along the path between small portal tracts and efferent hepatic venous branches and enzyme activities obtained from biochemical assays exhibited a strong positive correlation. The gradients of high periportal to lower perivenous glucose-6-phosphatase activities were analysed by profiles of optical density along these distances. Mapping optical densities in an image of equidensity range provided information on the distribution pattern of hepatic glucose-6-phosphatase over an extended two-dimensional area. This visualisation of histochemical enzyme reaction based on quantitative data supports the approach of sampling across the entire protal----hepatic venous distance disregarding parenchymal zonation. Utilities provided by computer assisted image analysis will have some bearing for further adequate quantitative description of liver function and structural make up.

Quantitative and qualitative histochemical investigation on NADP+-dependent dehydrogenases in the limiting plate and the residual parenchyma surrounding terminal hepatic venules

Activities of three NADP+-dependent enzymes (glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, isocitrate dehydrogenase) were demonstrated in the first layer of hepatocytes adjacent to terminal hepatic venules (perivenous limiting plate), and in the residual parenchyma of the perivenous zone of the acinus, in normally fed adult male Wistar rats, using a Lowry technique and a qualitative histochemical staining reaction. Enzyme activities of the glucose-6-phosphate dehydrogenase were significantly higher in the hepatocytes adjacent to terminal hepatic venules (ratio hepatocytes adjacent to terminal hepatic venules/residual parenchyma of the perivenous zone: 1.31). 6-Phosphogluconate dehydrogenase and isocitrate dehydrogenase were homogeneously distributed in the two areas measured (ratio: 1.04 and ratio: 1.0 respectively). With the qualitative histochemical staining reactions no differences were found.