Aquaporin 2 Expression in Human Fetal Kidney Development

Introduction: The metanephrogenic zone, renal cortex and renal pyramids develop into their final form by week 13. The metanephric kidney produces large quantities of diluted urine in order to maintain volumes of amniotic fluid. Aquaporins are transmembrane protein channels that enable water transport through biological membranes. Aquaporin 2 (AQP2) is a water channel found in the supranuclear region and apical area of the cell membrane of the kidneys collecting tubule cells. Its main function is reabsorption of water through vasopressin stimulation

Assessment of femoral bone osteoporosis in rats treated with simvastatin or fenofibrate

Background: The effects of two lipidlowering drugs, simvastatin and fenofibrate on osteoporosis in the femurs of healthy and ovariectomized female rats were investigated quantitatively by histological images and 1H NMR relaxometry. Methodology: The intertrabecular cavities percentage was estimated from numerically cleaned histological images which initially present both the trabecular bone architecture and bone marrow filling the intertrabecular pores. The eight weeks evolution of intertrabecular cavities percentage measured from histological images of randomly selected sections in ovariectomized rats femoral diaphysis is similar with the evolution of transverse relaxation time centre of gravity T2,CG, a selected parameter to quantify the changes in intertrabecular cavities dimensions from onedimensional (1D) transverse relaxation time T2 distributions. Results: The analysis of histological images recorded for non-ovariectomized rats show that the treatment with simvastatin and fenofibrate has a negative effect on the dimension of the femoral diaphysis trabecular bone. The analysis of 1D T2 distributions show that the simvastatin and fenofibrate lipid-lowering drugs produce different effects on different particular sections of studied rat bones, i.e. proximal part of femoris, diaphysis or distal epiphysis. Conclusions: Finally, it is shown that the effects of the treatments are strongly dependent on the duration of treatment

Expansion of Hepatic Stem Cell Compartment Boosts Liver Regeneration.

The hepatic stem cells reside periportally forming the canals of Hering in normal liver. They can be identified by their unique immunophenotype in rat. The oval cells, the progenies of stem cells invade deep the liver parenchyma after activation and differentiate into focally arranged small-and eventually trabecularly ordered regular hepatocytes. We have observed that upon the completion of intense oval cell reactions narrow ductular structures are present in the parenchyma, we propose to call them parenchymal ductules. These parenchymal ductules have the same immunophenotype [cytokeratin (CK)7-/CK19+/alpha-fetoprotein (AFP)-/delta-like protein (DLK)-] as the resting stem cells of the canals of Hering, but different from them reside scattered in the parenchyma. In our present experiments, we have investigated in an in vivo functional assay if the presence of these parenchymal ductules has any impact on a progenitor cell driven regeneration process. Parenchymal ductules were induced either by an established model of oval cell induction consisting of the administration of necrogenic dose of carbontetrachloride to 2-acetaminofluorene pretreated rats (AAF/CCl4) or a large necrogenic dose of diethylnitrosamine (DEN). The oval cells expanded faster and the foci evolved earlier after repeated injury in the livers with preexistent parenchymal ductules. When the animals were left to survive for one more year increased liver tumor formation was observed exclusively in the DEN treated rats. Thus, repeated oval cell reactions are not necessarily carcinogenic. We conclude that the expansion of hepatic stem cell compartment conceptually can be used to facilitate liver regeneration without an increased risk of tumorigenesis

Quantitative morphometric and immunohistochemical analysis and their correlates in cirrhosis – A study on explant livers

<div><p></p><p><b><i>Background.</i></b> Reproducible structural analysis was made on cirrhotic human liver samples in order to reveal potential connections between morphological and laboratory parameters. <b><i>Material and methods.</i></b> Large histological samples were taken from segment VII of 56 cirrhotic livers removed in connection with liver transplantation. Picro Sirius red and immunohistochemically (smooth muscle actin [SMA], cytokeratin 7 [CK7], Ki-67) stained sections were digitalized and morphometric evaluation was performed. <b><i>Results.</i></b> The Picro Sirius-stained fibrotic area correlated with the average thickness of the three broadest septa, extent of SMA positivity, alkaline phosphatase (ALP) values and it was lower in the viral hepatitis related cirrhoses than in samples with non-viral etiology. The extent of SMA staining increased with the CK7-positive ductular reaction. The proliferative activity of the hepatocytes correlated positively with the Ki-67 labeling of the ductular cells and inversely with the septum thickness. These data support the potential functional connection among different structural components, for example, myofibroblasts, ductular reaction and fibrogenesis but challenges the widely proposed role of ductular cells in regeneration. <b><i>Conclusion.</i></b>Unbiased morphological characterization of cirrhotic livers can provide valuable, clinically relevant information. Similar evaluation of routine core biopsies may increase the significance of this ‘Gold Standard’ examination.</p></div