scholarly journals The uptake and metabolism of chylomicron-remnant lipids by rat liver parenchymal and non-parenchymal cells in vitro

1985 ◽  
Vol 232 (2) ◽  
pp. 395-401 ◽  
Author(s):  
P M Lippiello ◽  
P J Sisson ◽  
M Waite
Keyword(s):  
Endothelial Cells ◽  
Rat Liver ◽  
Kupffer Cells ◽  
Liver Cell ◽  
Cholesterol Ester ◽  
Cell Types ◽  
Chylomicron Remnant ◽  
Parenchymal Cells ◽  
Uptake And Metabolism

The uptake and metabolism of chylomicron-remnant lipids by individual liver cell types was examined by incubating remnants with monolayer cultures of hepatocytes, Kupffer cells, and endothelial cells from rat liver. Remnants were prepared in vitro from radiolabelled mesenteric-lymph chylomicra, utilizing either purified lipoprotein lipase from bovine milk, or plasma isolated from heparinized rats. The resulting particles contained [3H]phosphatidylcholine and cholesterol, and [14C]oleate in the acylglycerol, phospholipid, fatty-acid and cholesterol-ester fractions. The capacities of the three cell types for uptake of both [3H]lipids and [14C]lipids were determined to be, on a per-cell basis, in the order: Kupffer greater than hepatocytes greater than endothelial. The relative proportions of [3H]phospholipid and total [3H]cholesterol taken up by hepatocytes and non-parenchymal cells remained constant with time. The uptake of [14C]oleoyl lipids by all three cell types was slightly greater than that of the total [3H]cholesterol and [3H]phospholipid components. There was evidence of cholesterol-ester hydrolysis and turnover of [14C]oleate in the phospholipid fraction in hepatocytes and Kupffer cells, but not endothelial cells, over the first 2 h. With both remnant preparations, these observations indicate that significant differences exist between the three major liver cell types with respect to the uptake and metabolism of remnant lipid components.

scholarly journals Liver endothelium and not hepatocytes or Kupffer cells have transferrin receptors

Blood ◽  
1984 ◽  
Vol 63 (2) ◽  
pp. 270-276
Author(s):  
R Soda ◽  
M Tavassoli
Keyword(s):  
Endothelial Cells ◽  
Rat Liver ◽  
Kupffer Cells ◽  
Liver Cell ◽  
Cell Suspensions ◽  
Transferrin Receptors ◽  
Visual Probe ◽  
Covalently Linked ◽  
Parenchymal Cells

Using a visual probe, consisting of latex minibeads covalently linked to transferrin (TF), we found that, in rat liver cell suspensions, transferrin receptors were limited to endothelial cells. Neither hepatocytes nor Kupffer cells contained an appreciable number of TF receptors. Specificity of this reaction was demonstrated by preincubation with non-derivatized TF, which inhibited the binding. This was further confirmed by fractionation of liver cell suspensions on metrizamide gradients. The uptake of either the visual probe or 125I- labeled TF was again limited to the endothelium-rich fraction. Transferrin bound to endothelial membrane was internalized at 37 degrees C, but not at 4 degrees C, via a coated pit system. Again, hepatocytes and Kupffer cells did not internalize the probe. The findings suggest that iron may be first taken up by liver endothelium and then transmitted to parenchymal cells. These results emphasize the generally unappreciated role of endothelium in the transport across the tissue-blood barrier.

scholarly journals Extracellular vesicle release and uptake by the liver under normo- and hyperlipidemia

2021 ◽  
Author(s):  
Krisztina Németh ◽  
Zoltán Varga ◽  
Dorina Lenzinger ◽  
Tamás Visnovitz ◽  
Anna Koncz ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Kupffer Cells ◽  
Liver Cell ◽  
High Fat Diet ◽  
Cell Types ◽  
Extracellular Vesicle ◽  
High Fat ◽  
Liver Sinusoidal Endothelial Cells ◽  
Sinusoidal Endothelial Cells

AbstractLiver plays a central role in elimination of circulating extracellular vesicles (EVs), and it also significantly contributes to EV release. However, the involvement of the different liver cell populations remains unknown. Here, we investigated EV uptake and release both in normolipemia and hyperlipidemia. C57BL/6 mice were kept on high fat diet for 20–30 weeks before circulating EV profiles were determined. In addition, control mice were intravenously injected with 99mTc-HYNIC-Duramycin labeled EVs, and an hour later, biodistribution was analyzed by SPECT/CT. In vitro, isolated liver cell types were tested for EV release and uptake with/without prior fatty acid treatment. We detected an elevated circulating EV number after the high fat diet. To clarify the differential involvement of liver cell types, we carried out in vitro experiments. We found an increased release of EVs by primary hepatocytes at concentrations of fatty acids comparable to what is characteristic for hyperlipidemia. When investigating EV biodistribution with 99mTc-labeled EVs, we detected EV accumulation primarily in the liver upon intravenous injection of mice with medium (326.3 ± 19.8 nm) and small EVs (130.5 ± 5.8 nm). In vitro, we found that medium and small EVs were preferentially taken up by Kupffer cells, and liver sinusoidal endothelial cells, respectively. Finally, we demonstrated that in hyperlipidemia, there was a decreased EV uptake both by Kupffer cells and liver sinusoidal endothelial cells. Our data suggest that hyperlipidema increases the release and reduces the uptake of EVs by liver cells. We also provide evidence for a size-dependent differential EV uptake by the different cell types of the liver. The EV radiolabeling protocol using 99mTc-Duramycin may provide a fast and simple labeling approach for SPECT/CT imaging of EVs biodistribution.

scholarly journals Liver endothelium and not hepatocytes or Kupffer cells have transferrin receptors

Blood ◽  
1984 ◽  
Vol 63 (2) ◽  
pp. 270-276 ◽  
Author(s):  
R Soda ◽  
M Tavassoli
Keyword(s):  
Endothelial Cells ◽  
Rat Liver ◽  
Kupffer Cells ◽  
Liver Cell ◽  
Cell Suspensions ◽  
Transferrin Receptors ◽  
Visual Probe ◽  
Covalently Linked ◽  
Parenchymal Cells

Abstract Using a visual probe, consisting of latex minibeads covalently linked to transferrin (TF), we found that, in rat liver cell suspensions, transferrin receptors were limited to endothelial cells. Neither hepatocytes nor Kupffer cells contained an appreciable number of TF receptors. Specificity of this reaction was demonstrated by preincubation with non-derivatized TF, which inhibited the binding. This was further confirmed by fractionation of liver cell suspensions on metrizamide gradients. The uptake of either the visual probe or 125I- labeled TF was again limited to the endothelium-rich fraction. Transferrin bound to endothelial membrane was internalized at 37 degrees C, but not at 4 degrees C, via a coated pit system. Again, hepatocytes and Kupffer cells did not internalize the probe. The findings suggest that iron may be first taken up by liver endothelium and then transmitted to parenchymal cells. These results emphasize the generally unappreciated role of endothelium in the transport across the tissue-blood barrier.

scholarly journals Cadmium metabolism by rat liver endothelial and Kupffer cells

1984 ◽  
Vol 221 (3) ◽  
pp. 631-636 ◽  
Author(s):  
T J Caperna ◽  
M L Failla
Keyword(s):  
Endothelial Cells ◽  
Rat Liver ◽  
Kupffer Cells ◽  
Metal Binding ◽  
Metal Salt ◽  
Extracellular Medium ◽  
Competitive Binding Assay ◽  
Monolayer Cultures ◽  
Parenchymal Cells

The metabolism of cadmium was investigated in Wistar-rat liver non-parenchymal cells. Kupffer and endothelial cells, the major cell populations lining the sinusoidal tracts, were isolated by collagenase dispersion and purified by centrifugal elutriation. At 20 h after subcutaneous injection of the metal salt (1.5 mg of Cd/kg body weight), endothelial cells accumulated 2-fold higher concentrations of Cd than did Kupffer or parenchymal cells. Most of the Cd in non-parenchymal cells was associated with cytosolic metallothionein (MT), the low-Mr heavy-metal-binding protein(s). When MT was quantified in cytosols from cells isolated from control rats by a 203Hg competitive-binding assay, low levels were found to be present in Kupffer, endothelial and parenchymal cells. Cd injection significantly increased MT levels in all three cell types. The induction of MT synthesis was investigated in vitro by using primary monolayer cultures. The incorporation of [35S]cysteine into MT increased 47% over constitutive levels in endothelial-cell cultures after the addition of 0.8 microM-Cd2+ to the medium for 10 h. MT synthesis in Kupffer cells was not observed. The lack of MT synthesis by monolayer cultures of Kupffer cells in vitro was associated with a decreased capacity of these cells to accumulate heavy metals from the extracellular medium. This apparent decreased ability to transport metals did not reflect a general defect in either cellular function or metabolic activity, since isolated Kupffer cells incorporated [3H]leucine into protein at rates comparable with those shown by liver parenchymal cells and readily phagocytosed particles.

scholarly journals The distribution, induction and isoenzyme profile of glutathione S-transferase and glutathione peroxidase in isolated rat liver parenchymal, Kupffer and endothelial cells

1989 ◽  
Vol 264 (3) ◽  
pp. 737-744 ◽  
Author(s):  
P Steinberg ◽  
H Schramm ◽  
L Schladt ◽  
L W Robertson ◽  
H Thomas ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Glutathione Peroxidase ◽  
Rat Liver ◽  
Peroxidase Activity ◽  
Cell Types ◽  
Transferase Activity ◽  
Glutathione Peroxidase Activity ◽  
Glutathione S Transferase ◽  
Liver Parenchymal ◽  
Parenchymal Cells

The distribution and inducibility of cytosolic glutathione S-transferase (EC 2.5.1.18) and glutathione peroxidase (EC 1.11.1.19) activities in rat liver parenchymal, Kupffer and endothelial cells were studied. In untreated rats glutathione S-transferase activity with 1-chloro-2,4-dinitrobenzene and 4-hydroxynon-2-trans-enal as substrates was 1.7-2.2-fold higher in parenchymal cells than in Kupffer and endothelial cells, whereas total, selenium-dependent and non-selenium-dependent glutathione peroxidase activities were similar in all three cell types. Glutathione S-transferase isoenzymes in parenchymal and non-parenchymal cells isolated from untreated rats were separated by chromatofocusing in an f.p.l.c. system: all glutathione S-transferase isoenzymes observed in the sinusoidal lining cells were also detected in the parenchymal cells, whereas Kupffer and endothelial cells lacked several glutathione S-transferase isoenzymes present in parenchymal cells. At 5 days after administration of Arocolor 1254 glutathione S-transferase activity was only enhanced in parenchymal cells; furthermore, selenium-dependent glutathione peroxidase activity decreased in parenchymal and non-parenchymal cells. At 13 days after a single injection of Aroclor 1254 a strong induction of glutathione S-transferase had taken place in all three cell types, whereas selenium-dependent glutathione peroxidase activity remained unchanged (endothelial cells) or was depressed (parenchymal and Kupffer cells). Hence these results clearly establish that glutathione S-transferase and glutathione peroxidase are differentially regulated in rat liver parenchymal as well as non-parenchymal cells. The presence of glutathione peroxidase and several glutathione S-transferase isoenzymes capable of detoxifying a variety of compounds in Kupffer and endothelial cells might be crucial to protect the liver from damage by potentially hepatotoxic substances.

Uptake and Degradation of Tissue Plasminogen Activator in Rat Liver

1988 ◽  
Vol 59 (03) ◽  
pp. 474-479 ◽  
Author(s):  
Monica Einarsson ◽  
Bård Smedsrød ◽  
Håkan Pertoft
Keyword(s):  
Endothelial Cells ◽  
Plasminogen Activator ◽  
Tissue Plasminogen Activator ◽  
Rat Liver ◽  
Liver Cells ◽  
Terminal Phase ◽  
Tissue Plasminogen ◽  
Liver Endothelial Cells ◽  
Parenchymal Cells

SummaryThe mechanism of uptake of tissue plasminogen activator (tPA) in rat liver was studied. Radio-iodinated tPA was removed from the circulation after intravenous administration in a biphasic mode. The initial half life, t1/2(α), and the terminal phase, t1/2(β), were determined to be 0.5 min and 7.5 min, resp. Separation of the liver cells by collagenase perfusion and density centrifugation, revealed that the uptake per cell was two to three times higher in the non-parenchymal cells than in the parenchymal cells.Endocytosis of fluorescein isothiocyanate-labelled or 125I-labelled tPA was studied in pure cultures of liver cells in vitro. Liver endothelial cells and parenchymal cells took up and degraded tPA. Endocytosis was more efficient in liver endothelial cells than in parenchymal cells, and was almost absent in Kupffer cells.Competitivb inhibition experiments showing that excess unlabelled tPA could compete with the uptake and degradation of 125I-tPA, suggested that liver endothelial cells and parenchymal cells interact with the activator in a specific manner. Endocytosis of trace amounts of 125I-tPA in cultures of liver endothelial cells and parenchymal cells was inhibited by 50% in the presence of 19 nM unlabelled tPA. Agents that interfere with one or several steps of the endocytic machinery inhibited uptake and degradation of 125I-tPA in both cell types.These findings suggest that 1) liver endothelial cells and parenchymal cells are responsible for the rapid hepatic clearance of intravenously administered tPA; 2) the activator is taken up in these cells by specific endocytosis, and 3) endocytosed tPA is transported to the lysosomes where it is degraded.

scholarly journals Hepatic lipase is localized at the parenchymal cell microvilli in rat liver

1997 ◽  
Vol 321 (2) ◽  
pp. 425-430 ◽  
Author(s):  
Belinda BREEDVELD ◽  
Kees SCHOONDERWOERD ◽  
Adrie J. M. VERHOEVEN ◽  
Rob WILLEMSEN ◽  
Hans JANSEN
Keyword(s):  
Endothelial Cells ◽  
Rat Liver ◽  
Kupffer Cells ◽  
Binding Capacity ◽  
Hepatic Lipase ◽  
Parenchymal Cell ◽  
Liver Cells ◽  
Minor Amount ◽  
Parenchymal Liver ◽  
Parenchymal Cells

Hepatic lipase (HL) is thought to be located at the vascular endothelium in the liver. However, it has also been implicated in the binding and internalization of chylomicron remnants in the parenchymal cells. In view of this apparent discrepancy between localization and function, we re-investigated the localization of HL in rat liver using biochemical and immunohistochemical techniques. The binding of HL to endothelial cells was studied in primary cultures of rat liver endothelial cells. Endothelial cells bound HL in a saturable manner with high affinity. However, the binding capacity accounted for at most 1% of the total HL activity present in the whole liver. These results contrasted with earlier studies, in which non-parenchymal cell (NPC) preparations had been found to bind HL with a high capacity. To study HL binding to the different components of the NPC preparations, we separated endothelial cells, Kupffer cells and blebs by counterflow elutriation. Kupffer cells and endothelial cells showed a relatively low HL-binding capacity. In contrast, the blebs, representing parenchymal-cell-derived material, had a high HL-binding capacity (33 m-units/mg of protein) and accounted for more than 80% of the total HL binding in the NPC preparation. In contrast with endothelial and Kupffer cells, the HL-binding capacity of parenchymal cells could account for almost all the HL activity found in the whole liver. These data strongly suggest that HL binding occurs at parenchymal liver cells. To confirm this conclusion in situ, we studied HL localization by immunocytochemical techniques. Using immunofluorescence, we confirmed the sinusoidal localization of HL. Immunoelectron microscopy demonstrated that virtually all HL was located at the microvilli of parenchymal liver cells, with a minor amount at the endothelium. We conclude that, in rat liver, HL is localized at the microvilli of parenchymal cells.

scholarly journals Multi-cellular 3D human primary liver cell culture elevates metabolic activity under fluidic flow

Lab on a Chip ◽  
2015 ◽  
Vol 15 (10) ◽  
pp. 2269-2277 ◽  
Author(s):  
Mandy B. Esch ◽  
Jean-Matthieu Prot ◽  
Ying I. Wang ◽  
Paula Miller ◽  
Jose Ricardo Llamas-Vidales ◽  
...  
Keyword(s):  
Cell Culture ◽  
Metabolic Activity ◽  
Kupffer Cells ◽  
Liver Cell ◽  
Low Cost ◽  
Stellate Cells ◽  
Cell Types ◽  
Liver Cell Culture ◽  
Parenchymal Cells

We have developed a low-cost liver cell culture device that creates fluidic flow over a 3D primary liver cell culture that consists of multiple liver cell types, including hepatocytes and non-parenchymal cells (fibroblasts, stellate cells, and Kupffer cells).

The galactose-specific receptor system in rat liver during development

Development ◽  
1987 ◽  
Vol 100 (1) ◽  
pp. 13-22
Author(s):  
L. Dini ◽  
L. Conti-Devirgiliis ◽  
S. Russo-Caia
Keyword(s):  
Endothelial Cells ◽  
Ligand Binding ◽  
Rat Liver ◽  
Binding Capacity ◽  
Specific Binding ◽  
Cell Types ◽  
Receptor System ◽  
In Situ Experiments

The number and distribution of galactose-specific binding sites were investigated in rat liver cells during perinatal development. Ligand binding to hepatocytes, macrophages and endothelial cells was followed with in vitro and in situ experiments by electron microscopy, using lactosylated bovine serum albumin adsorbed onto 5 nm colloidal gold particles as ligand. Binding capacity, starting at a late stage of fetal development, is very low both on the hepatocyte and on the macrophage surface, which show single particles statistically distributed. By contrast, bound particles are absent from fetal endothelial cells, which also lack the typical coated regions. In vivo, experiments at 37 degrees C show that endocytosis occurs to some extent in prenatal life. These results indicate that the expression of galactose-specific receptors' activity on the different liver cell types follows different developmental patterns, which are independently modulated.

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