Quantitative Assessment of the Rat Intrahepatic Biliary System by Three-Dimensional Reconstruction

Huang

The American Journal of Pathology

et al. 2004

Self Cite

105

Hepatic polycystic disease occurs alone or in combination with polycystic kidney disease (PKD). In autosomal recessive PKD (ARPKD), liver lesions are the major cause of morbidity and mortality in older patients. ARPKD is caused by a mutation to PKHD1 and the PCK rat is an orthologous model of disease. Recently, we showed that fibrocystin, Pkhd1 protein, is localized to primary cilia in rat cholangiocytes and that disruption of its ciliary expression results in biliary cystogenesis. This study describes biliary phenotype in the PCK rat using micro-computed tomography scanning and three-dimensional reconstruction, and light, scanning, and transmission microscopy. Our results show that the biliary tree undergoes extensive remodeling resulting in bile duct dilatation, focal budding, and formation of cysts that are initially connected to bile ducts, but throughout time separate from them. Progressive liver enlargement results from massive cyst formation while liver parenchymal volume remains unchanged. Cilia in cystic cells are abnormal consistent with the notion that the primary defect in ARPKD resulting in cystogenesis may be linked to ciliary dysfunction. Our results suggest that the PCK rat is a useful model for studies of biliary cystogenesis and treatment options of inherited cystic liver disease.

Section: Three-dimensional Reconstruction Of the Intrahepatic Biliarymentioning

confidence: 99%

Section: Three-dimensional Reconstruction Of the Intrahepatic Biliarymentioning

confidence: 99%

Biliary Dysgenesis in the PCK Rat, an Orthologous Model of Autosomal Recessive Polycystic Kidney Disease

Huang

The American Journal of Pathology

et al. 2004

Self Cite

105

American Journal of Physiology-Regulatory, Integrative and Comp

“…Furthermore, the capabilities of micro-CT make it an ideal tool to study the three-dimensional architecture of basic functional units of small organs such as those found in rodents (48). In addition to bone tissue, micro-CT has been used to study renal microvasculature (37), the microvasculature of liver (99), the biliary system of liver (62), the microvasculature of lung (47), myocardial microvasculature (51,82), and the vasa vasorum of coronary arteries (56,60). The images obtained with micro-CT represent three-dimensional arrays of voxels having values representing X-ray opacities.…”

Section: Three-dimensional Analysis Of Serial Sectionsmentioning

confidence: 99%

The use of microcomputed tomography to study microvasculature in small rodents

Bentley

Ortiz

Ritman

et al. 2002

Self Cite

135

109

The use of microcomputed tomography to study microvasculature in small rodents. Am J Physiol Regulatory Integrative Comp Physiol 282: R1267-R1279, 2002 10.1152/ajpregu.00560.2001.-Appropriate nephron function is dependent on the intrarenal arrangement of blood vessels. The preferred and primary means to study the architecture of intrarenal circulation has been by filling it with opaque substances such as india ink, radio-opaque contrast material, or various polymers for study by light or scanning electron microscopy. With such methodologies, superficial vessels may obscure deep vessels and little quantitative information may be obtained. Serial-section microtomy has not been practical because of problems relating to alignment and registration of adjacent sections, lost sections, and preparation time and effort. Microcomputed tomography (micro-CT) overcomes such limitations and provides a means to study the three-dimensional architecture of filled vessels within an intact rodent kidney and to obtain more quantitative information. As an example of micro-CT's capabilities, we review the use of micro-CT to study the alterations in renal microvasculature caused by the development of liver cirrhosis after chronic bile duct ligation. In this example, micro-CT evidence shows a selective decrease in cortical vascular filling in the kidney, with a maintenance of medullary vascular filling. These changes may contribute to the salt and water retention that accompanies cirrhosis. These results indicate that micro-CT is a promising method to evaluate renal vascular architecture in the intact rodent kidney relative to physiological and pathological function. kidney; imaging; microcirculation; vasculature APPROPRIATE NEPHRON FUNCTION appears to be dependent on the detailed three-dimensional interrelationship of blood vessels with the tubular components. Many techniques and/or methods have been developed to examine the microanatomic arrangement of pre-and postglomerular vasculature (4,29,36,40,54,55,59,71,98). In this respect, such efforts were prompted by early studies showing that urinary excretion varied in relation to the intrarenal environment and was dependent on the coupling of renal microcirculation and tubular components. In 1947, Trueta and colleagues (96), studying the crush syndrome in rabbits, observed that there was a shift of blood flow from the renal cortex to the medulla during hemorrhage. They suggested this shift to be the major explanation for the lack of urine flow, despite a preservation of renal blood flow (RBF). The shift of blood flow within the renal cortex from superficial short nephrons to deep long nephrons was later observed in sodium-retaining states such as cardiac insufficiency, hepatic cirrhosis, or hypovolemia (1,18,53,104). showed that changes in renal perfusion pressure, within a range (75-130 mmHg) in which RBF remains unchanged (RBF autoregulation), were followed by dramatic changes in sodium excretion. This situation is comparable to that seen in the early stages Address for reprint requ...

Journal of Pharmacology and Experimental Therapeutics

“…The volume of hepatocytes in liver was calculated by using a rat liver hepatocellularity of 120 million cells per gram of liver (SohleniusSternbeck, 2006) and a volume of 3.9 ml for a million hepatocytes (Reinoso et al, 2001). Volume of the intrahepatic biliary tree was set to 50 ml (Blouin et al, 1977;Masyuk et al, 2001). An initial estimate for the apical efflux clearance (CL ae ) was iteratively optimized with the 1ABT 1 RIF data set to obtain the observed rate of biliary excretion with concentration in the apical membrane as the driving concentration.…”

Section: Mathematical Modeling and Simulationmentioning

confidence: 99%

Intracellular Unbound Atorvastatin Concentrations in the Presence of Metabolism and Transport

Kulkarni¹,

Korzekwa²,

Nagar³

2016

Accurate prediction of drug target activity and rational dosing regimen design require knowledge of drug concentrations at the target. It is important to understand the impact of processes such as membrane permeability, partitioning, and active transport on intracellular drug concentrations. The present study aimed to predict intracellular unbound atorvastatin concentrations and characterize the effect of enzyme-transporter interplay on these concentrations. Single-pass liver perfusion studies were conducted in rats using atorvastatin (ATV, 1 mM) alone at 4°C and at 37°C in presence of rifampin (RIF, 20 mM) and 1-aminobenzotriazole (ABT, 1 mM), separately and in combination. The unbound intracellular ATV concentration was predicted with a five-compartment explicit membrane model using the parameterized diffusional influx clearance, active basolateral uptake clearance, and metabolic clearance.Chemical inhibition of uptake and metabolism at 37°C proved to be better controls relative to studies at 4°C. The predicted unbound intracellular concentration at the end of the 50-minute perfusion in the 1ABT , 1ABT1RIF, and the ATV-only groups was 6.5 mM, 0.58 mM, and 5.14 mM, respectively. The predicted total liver concentrations and amount recovered in bile were within 0.94-1.3 fold of the observed value in all groups. The fold difference in total liver concentration did not always extrapolate to the fold difference in predicted unbound concentration across groups. Together, these results support the use of compartmental modeling to predict intracellular concentrations in dynamic organ-based systems. These predictions can provide insight into the role of uptake transporters and metabolizing enzymes in determining drug tissue concentrations.