Galactosyl Serum Albumin Research Articles

Comparison of T1 Mapping on Gadoxetic Acid-Enhanced Magnetic Resonance Imaging With Conventional Functional Liver Reserve Indices and Technetium-99m Galactosyl Serum Albumin Scintigraphy.

Background Gadoxetic acid (EOB)-enhanced magnetic resonance imaging (MRI) (EOB-MRI) can be used as a one-stop examination for detecting liver tumors and evaluating liver function. Purpose The study aimed to assess the functional liver reserve (FLR) using the T1 map from the hepatobiliary phase of EOB-MRI by conducting a comparison with the results of conventional FLR tests and the technetium-99m (99mTc)-galactosyl serum albumin (GSA) scintigraphy. Materials and methods The retrospective data from 43 patients were included in the study. The regions of interest covered the entire liver. The data acquired from each EOB-MRI slice were summed to derive voxel-by-voxel values. The average sum of the T1 values (pre- and post-enhancement), ∆T1, and ∆T1 ratios were calculated. The HH15, LHL15, and LU15 values were calculated from the GSA scintigraphy. The results of conventional FLR tests, such as the indocyanine green retention rate at 15 min (ICGR15), the Child-Pugh classification (CPC), and the albumin-bilirubin (ALBI) and albumin-indocyanine green evaluation (ALICE) scores, were obtained. Results The T1 pre- and post-sum values showed a weak correlation with the LHL15 (r=0.36 and 0.38, respectively). A strong correlation was observed between the liver volume and the T1 pre- and post-sum values (r=0.86 and 0.76, respectively). A moderate correlation was observed between the T1 mean and the ALBI and ALICE values (r=0.58 and 0.49, respectively) and between the ∆T1 ratio and the CPC, ALBI, and ALICE values (r=-0.40, 0.58, and -0.55, respectively). The T1 post-sum values showed a moderate correlation with the ALBI scores (r=0.47) and a weak correlation with the ALICE scores (r=0.38). Furthermore, the LU15 values showed a weak correlation with the ICGR15 and model for end-stage liver disease (MELD) scores (r=-0.32 and -0.34, respectively). Conclusions Representative indices, such as the T1 mean and ∆T1 ratio, demonstrated a better relationship with conventional FLR indices compared with volumetric radiological indices. Therefore, we propose that the T1 post-sum can be used as an FLR index.

Current status of preoperative risk assessment for posthepatectomy liver failure in patients with hepatocellular carcinoma.

Liver resection is an effective therapeutic option for patients with hepatocellular carcinoma. However, posthepatectomy liver failure (PHLF) remains a major cause of hepatectomy-related mortality, and the accurate prediction of PHLF based on preoperative assessment of liver functional reserve is a critical issue. The definition of PHLF proposed by the International Study Group for Liver Surgery has gained acceptance as a standard grading criterion. Liver function can be estimated using a variety of parameters, including routine blood biochemical examinations, clinical scoring systems, dynamic liver function tests, liver stiffness and fibrosis markers, and imaging studies. The Child-Pugh score and model for end-stage liver disease scores are conventionally used for estimating liver decompensation, although the alternatively developed albumin-bilirubin score shows superior performance for predicting hepatic dysfunction. Indocyanine green clearance, a dynamic liver function test mostly used in Japan and other Asian countries, serves as a quantitative estimation of liver function reserve and helps determine indications for surgical procedures according to the estimated risk of PHLF. In an attempt to improve predictive accuracy, specific evaluation of liver fibrosis and portal hypertension has gained popularity, including liver stiffness measurements using ultrasonography or magnetic resonance elastography, as well as noninvasive fibrosis markers. Imaging modalities, including Tc-99m-labeled galactosyl serum albumin scintigraphy and gadolinium-enhanced magnetic resonance imaging, are used for preoperative evaluation in combination with liver volume. This review aims to provide an overview of the usefulness of current options for the preoperative assessment of liver function in predicting PHLF.

Validation set analysis to predict postoperative outcomes by technetium-99m galactosyl serum albumin scintigraphy for hepatectomy.

The indocyanine green retention rate at 15 min (ICGR15) is a gold standard parameter of liver function when deciding on the extent of hepatectomy. However, ICGR15 is influenced by several hepatic conditions. To evaluate auxiliary preoperative liver functional reserve, we examined the clinical significance of modified parameters by blood tests and technetium-99m galactosyl human serum albumin (Tc-GSA) scintigraphy. We measured liver function parameters, including the hepatic uptake ratio (LHL15) and the blood pool clearance index (HH15) of Tc-GSA and their modified formulae [LHL/HH15, LHL minus HH15, and converted ICGR15 (cICGR15) from a preliminary study] in 229 patients, including 18 with biliary obstruction. The mean values of LHL15/HH15, LHL minus HH15, and cICGR15 were 1.646 ± 0.295, 0.347 ± 0.116, and 13.2 ± 5.3%, respectively. These parameters correlated significantly with other liver functions measured by blood tests except for the bilirubin level (P < 0.05) although the actual ICGR15 level correlated positively with the bilirubin level. The difference of ICGR15 (ICGR15 minus cICGR15) in patients with biliary obstruction tended to be higher in comparison with that in patients without biliary obstruction (P = 0.044). Values of LHL/HH15, LHL minus HH15, and the cICGR15 were not significantly associated with postoperative complications. The modified parameters of Tc-GSA were useful for evaluating hepatic function in patients with high bilirubinemia due to biliary obstruction. However, it remains difficult to establish a more reliable parameter as a standard hepatic function test instead of ICGR15.

Near-infrared photoimmunotherapy with galactosyl serum albumin in a model of diffuse peritoneal disseminated ovarian cancer.

Near-infrared photoimmunotherapy (NIR-PIT) is a highly cell-selective cancer therapy based on an armed antibody conjugated with a phthalocyanine-based photo-absorber, IRDye700DX (IR700). NIR-PIT can quickly kill target cells that express specific proteins on the cellular membrane but only when the antibody-IR700 conjugate binds to the cell membrane and is then exposed to NIR light. NIR-PIT is highly selective based on the specificity of the antibody. Galactosyl serum albumin (GSA) is composed of albumin decorated with galactose molecules conjugated to the carboxyl groups of albumin. GSA binds to beta-D-galactose receptors, a surface lectin, which are overexpressed on the cell surface of many cancers, including ovarian cancers and is quickly internalized after binding. Here, we demonstrate the feasibility of NIR-PIT in a model of disseminated peritoneal ovarian cancer (SHIN3 cells) using GSA-IR700 that binds to beta-D-galactose receptors. GSA-IR700 bound quickly to SHIN3 cells, then accumulated in the endo-lysosomes. Cell-specific killing was observed in vitro, yet a relatively large dose of NIR light exposure was required for cell killing compared to antibody-IR700 conjugates. To evaluate in vivo therapeutic effects of GSA-IR700 NIR-PIT, peritoneal disseminated SHIN3 tumor-bearing mice were separated into four groups: no treatment; NIR light only; GSA-IR700 only; and GSA-IR700 NIR-PIT. Repeated NIR-PIT showed significant suppression of tumor based on bioluminescence compared to the other groups (p < 0.05). Thus, repeated NIR-PIT using GSA-IR700 can achieve efficient antitumor effects, although GSA-IR700 NIR-PIT was less effective than antibody-IR700 NIR-PIT conjugates likely due to the rapid internalization of GSA-IR700.

Liver Function Assessment by Magnetic Resonance Imaging

Liver function assessment by hepatocyte-specific contrast-enhanced magnetic resonance imaging is becoming a new biomarker. Liver function can be assessed by T1 mapping (reduction rate) and signal intensity measurement (relative enhancement ratio) before and after GD-EOB-DTPA (gadoxetic acid) administration, as alternative to Tc-99m galactosyl serum albumin scintigraphy, 99m Tc-labeled mebrofenin scintigraphy, and indocyanine green clearance test. Magnetic resonance imaging assessment of liver function can enable diagnosis of cirrhosis, nonalcoholic fatty liver disease associated fibrosis and steatohepatitis, primary sclerosing cholangitis, toxic hepatitis, and chemotherapy and radiotherapy-related changes, which may be only visible on hepatobiliary phase images. Simple visual assessment of signal intensity at hepatobiliary phase images is important for the diagnosis of different patterns of liver dysfunction including diffuse, lobar, segmental, and subsegmental forms. Furthermore, preoperative assessment of liver function is feasible before oncologic hepatic surgery, which may be important to prevent posthepatectomy liver failure and to estimate future remnant volume. Functional magnetic resonance cholangiography obtained by T1-weighted images at hepatobiliary phase can allow diagnosis of acalculous cholecystitis, biliary leakage, bile reflux to the stomach, sphincter of oddi dysfunction, and lesions with communication to biliary tree. Functional information can be easily obtained when Gd-EOB-DTPA is used for liver magnetic resonance imaging.

Correlation between morphological and functional liver volume in each sector using integrated SPECT/CT imaging by computed tomography and technetium-99m galactosyl serum albumin scintigraphy in patients with various diseases who had undergone hepatectomy

The aim of the study was to accurately examine the functional volume (RI-vol) of the hepatic segments on single photon emission computed tomography/computed tomography (CT) fusion imaging by technetium-99m galactosyl human serum albumin scintigraphy and compare it with the RI-vol and morphological volume obtained on computed tomography (CT-vol). In 60 patients with various liver background statuses who had undergone hepatectomy, the RI-vol and CT-vol were examined in each sector using imaging analysis. The values from a control group (n=91) were used as reference data. The mean RI-vol and CT-vol of the right liver were 64 ± 10 and 63 ± 6%, respectively, whereas the values for the left liver were 36 ± 10 and 37 ± 6%, respectively. Compared with the control group, the ratios in each hemiliver were similar. The mean RI-vol and CT-vol for each sector were also similar, and significant positive correlations were identified between the two volumes (P<0.01). In four patients with hepatic tumors involving the main hepatic vessels or the bile duct and in 10 patients who had undergone portal vein embolization, the actual RI-vol in the injured sector was significantly decreased compared with CT-vol (P<0.05). There were marked changes in functional volume in segment 6+7 and segment 2+3 after portal vein embolization (P<0.05). Volumetric measurement using single photon emission computed tomography/CT imaging with technetium-99m galactosyl human serum albumin scintigraphy is useful for evaluating the functional volume in separated livers and offers a good reflection of the background liver status.

Liver analysis using gadolinium‐ethoxybenzyl‐diethylenetriamine pentaacetic acid‐enhanced magnetic resonance imaging: Correlation with histological grading and quantitative liver evaluation prior to hepatectomy

To examine the effectiveness of gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) in the assessment of parenchymal liver fibrosis and quantitative liver function prior to hepatectomy. Between July 2008 and September 2011, the data of 93 consecutive patients undergoing preoperative Gd-EOB-DTPA-enhanced MRI were analyzed, including serum fibrosis marker levels (hyaluronic acid, type IV collagen), 15-min retention rates of indocyanine green (ICG-R15) in the ICG clearance test, and technetium-99m galactosyl serum albumin scintigraphy results. Liver intensity values were obtained by calculating the differences between the intensity of the liver and that of other organs in the hepatobiliary phase. Degrees of liver fibrosis were quantitatively assessed (F0-4). MRI data were correlated with the prospectively acquired clinical data. Varying degrees of liver fibrosis were detected in 31 of the 93 patients. The intensity ratio of the liver to spinal cord on MRI negatively correlated with hepatic fibrosis (R = -0.479, P < 0.001) and ICG-R15 (R = -0.492, P < 0.001). When patients with F0-2 (normal/moderate) and F3-4 (severe) liver fibrosis were compared, the intensity ratio of the enhanced liver to spinal cord (IRLS) on MRI was significantly lower in the F3-4 group than in the F0-2 group. IRLS was correlated with liver fibrosis, and, when an IRLS criterion of less than 1.702 was used, severe liver fibrosis could be predicted with 68.8% sensitivity and 93.5% specificity. Preoperative Gd-EOB-DTPA-enhanced MRI analysis can detect quantitative indicators of liver fibrosis and function, thus aiding the assessment of hepatic remnants prior to hepatectomy.

Quantitative analysis of liver function using superparamagnetic iron oxide- and Gd-EOB-DTPA-enhanced MRI: Comparison with Technetium-99m galactosyl serum albumin scintigraphy

To examine whether or not the parameters regarding the signal intensity of the liver parenchyma on superparamagnetic iron oxide (SPIO)- and gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced MRI are correlated with the parameters of Technetium-99m galactosyl serum albumin ((99m)Tc-GSA) scintigraphy. This retrospective study consisted of 55 and 33 patients who underwent SPIO- and Gd-EOB-DTPA-enhanced MRI in addition to (99m)Tc-GSA scintigraphy, respectively. For each patient, we calculated Pre R2* and Pre R2, which are equivalent to R2* (=1/T2*) and R2 (=1/T2) values of the liver parenchyma; ΔR2* and ΔR2, which represent differences in R2* and R2 values of the liver parenchyma before and after administration of SPIO; and the increase rates of both the liver-to-spleen signal intensity ratio (LSR) and the liver-to-major psoas muscle signal intensity ratio (LMR) on the hepatobiliary phase compared with the precontrast image. For (99m)Tc-GSA scintigraphy, the receptor index LHL15 and the blood clearance index HH15 were recorded. Regression analysis showed a moderate correlation between Pre R2* and LHL15 (P<0.05). Mild to moderate correlations were also obtained between any combination of ΔR2* and ΔR2 on the one hand, and LHL15 and HH15 on the other (P<0.05). There were moderate correlations between any combination of increase rates of LSR and LMR on the one hand, and LHL15 and HH15 on the other (P<0.05-0.001). Pre R2*, ΔR2*, ΔR2 and the increase rates of LSR and LMR could be used as quantitative indicators of liver function.

Relationship of Hepatic Functional Parameters with Changes of Functional Liver Volume Using Technetium-99m Galactosyl Serum Albumin Scintigraphy in Patients Undergoing Preoperative Portal Vein Embolization: A Follow-Up Report

To identify predictors of changes in functional hepatic volumes after portal vein embolization (PVE) before hepatectomy, we examined the relationship between hepatic functional parameters and changes in functional volume of the embolized and non-embolized liver based on a previous volumetric analysis. Subjects were 24 patients who underwent PVE, which was performed through the trans-ileocolic vein (n = 4) or by percutaneous transhepatic puncture (n = 20). The RI liver volume parameter was measured by liver scintigraphy with technetium-(99m) galactosyl human serum albumin ((99m)Tc-GSA). Computed tomography (CT) volume parameter was also measured. Significant atrophy of the embolized liver and hypertrophy of the non-embolized liver (change of 72 ± 108 cm(3) and 111 ± 91 cm(3), respectively) (change of 7.8%) was observed after PVE. The change in these RI volume parameters (change of 173 ± 175 cm(3) and 145 ± 137 cm(3) , respectively) (16.5%) was significantly greater than CT volume parameters (P < 0.01). CT vol and RI vol in the embolized and non-embolized liver were well correlated (r = 0.75 and 0.69, respectively). However, the correlation between CT and RI volume parameters in the embolized and non-embolized liver after PVE was very weak (r = 0.17 and 0.03, respectively). Only alkaline phosphatase level correlated negatively with atrophic CT volume parameter of the embolized liver (r = -0.455, P < 0.05). When compared with CT volume parameter, more parameters were significantly correlated with changes of RI volume parameter in the embolized liver: pre-PVE pressure; ICGR15; and serum levels of hyaluronate, total bilirubin, albumin, and alkaline phosphatase. Only platelet count was significantly correlated with hypertrophy of the non-embolized liver. RI volume parameter might more accurately reflect functional changes in the embolized liver and non-embolized liver than CT volume parameter. Correlated parameters might allow us to predict the functional effect of PVE.

Usefulness of measuring hepatic functional volume using Technetium-99m galactosyl serum albumin scintigraphy in bile duct carcinoma: report of two cases

We report the usefulness of measuring functional liver volume in two patients undergoing hepatectomy. Case 1 involved a 47-year-old man with hepatitis B virus infection. The indocyanine green test retention rate at 15 min (ICGR15) was 14%. Liver uptake ratio (LHL15) by technetium-99 m galactosyl human serum albumin ((99m)Tc-GSA) liver scintigraphy was 0.91. The patient displayed hilar bile duct carcinoma necessitating right hepatectomy. After preoperative portal vein embolization (PVE), future remnant liver volume became 54% and functional volume by (99m)Tc-GSA became 79%. Although the permitted resected liver volume was lower than the liver volume, scheduled hepatectomy was performed following the results of functional liver volume. Case 2 involved a 75-year-old man with diabetes. ICGR15 was 27.4% and LHL15 was 0.87. The patient displayed bile duct carcinoma located in the upper bile duct with biliary obstruction in the right lateral sector. The right hepatectomy was scheduled. After PVE, future remnant volume became 68% and functional volume became 88%. Although ICGR15 was worse as 31%, planned hepatectomy was performed due to the results of functional volume. In the liver with biliary obstruction or portal embolization, functional liver volume is decreased more than morphological volume. Measurement of functional volume provides useful information for deciding operative indication.

Targeted optical fluorescence imaging of human ovarian adenocarcinoma using a galactosyl serum albumin‐conjugated fluorophore

Achieving maximal cytoreduction during surgery is a critical prognostic factor for women with advanced-stage ovarian cancer. Targeting optical imaging agents directly to ovarian cancer cells by attaching them to galactosyl (galactosamine-conjugated) serum albumin, whose sugar residues bind surface lectins that are expressed in certain ovarian adenocarcinomas, may improve metastatic tumor identification and resection. Thus, we sought to demonstrate that galactosyl serum albumin-conjugated fluorophores would be a robust mechanism through which to target ovarian cancer by evaluating its tumor-targeting capability in nine human ovarian adenocarcinoma cell lines. The optical fluorophore rhodamine green was conjugated to galactosyl serum albumin, a non-immunogenic targeting molecule. Galactosyl serum albumin-rhodamine green's ability to target nine human ovarian adenocarcinoma cell lines was evaluated by flow cytometry, fluorescence microscopy and in vivo optical fluorescence imaging using female athymic nu/nu mice. All nine cell lines tested bound galactosyl serum albumin-rhodamine green more effectively than non-glycosylated controls (P < 0.0001). Fluorescence microscopy demonstrated that galactosyl serum albumin-rhodamine green was internalized into each cell line in a galactosamine-dependent manner. In vivo optical fluorescence images of intraperitoneal tumor-bearing mice acquired 3 h after intraperitoneal injection of galactosyl serum albumin-rhodamine green successfully differentiated between tumor and normal tissue. This technique also allowed the visualization of submillimeter-sized ovarian tumor implants. These results indicate that galactosyl serum albumin-rhodamine green can selectively target a variety of human ovarian adenocarcinomas for optical fluorescence imaging and thus may improve intraoperative tumor detection and resection.

Relationship between indocyanine green test and technetium-99m galactosyl serum albumin scintigraphy in patients scheduled for hepatectomy: Clinical evaluation and patient outcome

The clinical significance of and discrepancy between the indocyanine green retention rate at 15min (ICGR15) and liver activity at 15min (LHL15) by technetium-99m galactosyl human serum albumin ( [Formula: see text] -GSA) scintigraphy and clinical outcome were examined in 140 patients who underwent hepatectomy. Both ICGR15 and LHL15 were significantly associated with portal pressure and liver function tests, fibrotic degree and regeneration of the remnant liver ( [Formula: see text] ). The significance of the correlation between LHL15 and liver functions and HAI score appeared to be better than that with ICGR15. A significant correlation was observed between ICGR15 and LHL15 ( [Formula: see text] 0.591, [Formula: see text] ) for all but 12 patients (8.6%). Of three patients with LHL15 better than ICGR15, two had obstructive jaundice and one had an intrahepatic shunt. Patient outcome was relatively good. In nine patients with LHL15 worse than ICGR15, the HAI score was higher (=7) and six of the nine had hepatic failure or uncontrolled ascites. Complications were frequently observed in patients with LHL15 below 0.875 (80% versus 30%, [Formula: see text] ). Our results indicate that [Formula: see text] -GSA scintigraphy is a reliable auxiliary test of hepatic functional reserve combined with ICGR15 for selecting the extent of hepatectomy and predicting patient outcome.

Quantification of intrahepatic non-uniform distributions for assessing impaired function of liver using 99Tcm-DTPA-galactosyl serum albumin liver SPECT scintigraphy

Quantitative evaluation of intrahepatic non-uniform distribution was attempted by functional volumetric analysis of liver single photon emission computed tomography (SPECT) scintigraphy using 99Tcm-diethylenetriaminepentaacetic acid galactosyl serum albumin (99Tcm-GSA) (185 MBq). A total of 148 patients were classified into three groups: diffuse liver disease, liver disease with space-occupying lesions, and non-hepatic disease. The volume obtained at the 10% cut-off threshold from reconstructed liver-specific SPECT images was assumed to be the functional total hepatic volume, and the functional volume rates were calculated every 10% threshold width from 10% to 100%. The hepatic distribution index (D index) was calculated from the sum of absolute differences from the control. The hepatic D index in liver cirrhosis was significantly higher than in hepatitis and other diffuse liver diseases, and the index in liver disease with primary malignant neoplasm was significantly higher than in liver disease with metastasis or a benign-space occupying lesion. Additionally, it was significantly negatively correlated with LHL15, and positively correlated with the clinical severity. However, in stages II and III, with which LHL15 did not significantly correlate, the hepatic D index matched the severity of hepatic impairment. The hepatic D index evaluates distribution of functional hepatocytes and may provide a new clinical method for quantitatively assessing hepatic impairment.

Imaging of intraperitoneal tumors with technetium-99m GSA.

99mTc labeled galactosyl serum albumin (GSA) has been used clinically as a receptor-binding agent for the assessment of liver function. The aim of this study was to investigate the usefulness of 99mTc-GSA in intraperitoneal (i.p.) tumor imaging. A tumor model was established by i.p. inoculating nude mice with human ovarian cancer cell SHIN-3, or colon cancer cell LS 180. Radiolabels were i.p. injected into the tumor-bearing mice and the biodistribution of radioactivity was examined. After administration, 99mTc-GSA rapidly accumulated in the tumor. The tumor uptake was 5.82-8.46 %ID/g from 30 min to 6 h after the injection. Radioactivity in the blood was very low, less than 0.3 %ID/g, resulting in high tumor-to-blood ratio. Tumors could be clearly seen by scintigraphic imaging. Accumulation of i.p.-injected 99mTc labeled human serum albumin (HSA) in i.p. tumors was similar to that of 99mTc-GSA, but radioactivity of 99mTc-HSA in the circulation was high, resulting in a significantly lower tumor-to-blood ratio. In conclusion, 99mTc-GSA, when i.p. injected, accumulated in i.p. tumors and cleared from circulation rapidly, which would make it useful for the imaging of i.p. tumors.

Compartmental analysis of asialoglycoprotein receptor scintigraphy for quantitative measurement of liver function: a multicentre study.

A multicentre study on multicompartmental analysis of hepatic scintigraphy using technetium-99m labelled galactosyl serum albumin (GSA), which binds to the asialoglycoprotein receptor, was carried out at seven institutions in Japan. Seventy-four patients with liver disease received 3 mg (185 MBq) of 99mTc-GSA by intravenous injection. Sequential scanning was performed 30 min after injection to obtain anterior images of the heart and liver, followed by single-photon emission tomography (SPET). The indices included in this analysis were hepatic blood flow (Q) and maximal receptor binding rate (Rmax), which showed a good correlation with semiquantitative ratio indices for 99mTc-GSA, namely the retention rate in blood (HH15) and the hepatic uptake rate (LHL15). Q and Rmax also showed a significant correlation with other measures of hepatic function. When patients were grouped according to the severity of chronic liver damage (hepatocellular functional damage), Q was reduced in the moderate and severe groups, while Rmax was reduced in proportion to the functional stage. Both parameters showed no inter-institution difference using analysis of co-variance with the functional stage as a co-variant. With regard to the hepatic uptake rate, anterior planar images and SPET images gave similar results for Q and Rmax. Acquisition times of 15 or 30 min provided the same results. The multicompartmental model analysis permitted comparable results to be obtained at institutions using different gamma cameras, and is therefore considered a universally applicable method. These results indicate that Q and Rmax are useful general indices for evaluating the functional reserve capacity of the liver.

Uptake of toxic silica particles by isolated rat liver macrophages (Kupffer cells) is receptor mediated and can be blocked by competition.

Silica particles (quartz dust) are toxic to macrophages after their uptake into these cells. These experiments describe the opsonization mechanism(s) and macrophage receptor(s) involved in silica uptake. Freshly isolated rat liver macrophages (Kupffer cells) were incubated at 37 degrees C with silica particles in the presence or absence of autologous or heterologous plasma or purified plasma fibronectin and cell viability was assessed at various times. Within 60 min of coincubation, > 80% of macrophages were lysed in the presence of plasma or purified fibronectin but not in their absence (viability > 90%). Lysis was slower with defibronectinized plasma (28% in 60 min). Macrophages could be protected from lysis by addition of the monosaccharide N-acetyl-D-galactosamine but not by N-acetyl-D-glucosamine. Galactosylated serum albumin but not mannosylated albumin or native albumin exerted full protection from lysis. The pentapeptide GRGDS also prevented macrophage lysis in synergy with N-acetyl-galactosamine. Enzymatic deglycosylation of fibronectin reduced lysis significantly. These findings indicate an important opsonizing activity for fibronectin and dual recognition via the lectin-like galactose-specific binding activity of membrane-associated C-reactive protein and by integrin receptor(s). Binding experiments (at 4 degrees C) revealed initial binding as primarily galactose-inhibitable, suggesting integrin-mediated binding as a later event necessary for effective uptake.

Receptor-mediated endocytosis of polymeric IgA and galactosylated serum albumin in rat liver. Evidence for intracellular ligand sorting and identification of distinct endosomal compartments.

Rat polymeric IgA (pIgA) and galactosylated bovine serum albumin (GalBSA), once injected to rats, are avidly taken up by hepatocytes via receptor-mediated endocytosis. Of injected pIgA, 64% was transferred undigested into bile within 3 h, with a peak at 30-45 min. GalBSA was essentially digested in lysosomes. By electron microscopy using ligand-peroxidase conjugates, both ligands were internalized through coated pits/coated vesicles into similar electron-lucent vesicles and tubules. Subsequently, pIgA remained mostly associated with small vesicles clustering around and fusing with bile canaliculi, while GalBSA was predominantly found in large, heterogeneous endocytic structures and in lysosomes. By subcellular fractionation, they were associated at 3 min after injection with structures that similarly sedimented in the P fraction (250 000 - 3 X 10(6) X g X min) and equilibrated at densities of about 1.13 g/ml in sucrose gradients. At 10 min and 20 min, pIgA distribution remained mostly in the P fraction at the same equilibrium density. A minor component of the pIgA distribution was found at the density of lysosomes, but contrary to lysosomal enzymes, its distribution was not affected by Triton WR 1339. In contrast to pIgA, GalBSA was progressively recovered in the L fraction (33 000 - 250 000 X g X min) with organelles equilibrating around 1.11 g/ml, and, by 20-45 min, was found in the ML fraction (10 000 - 250 000 X g X min), around 1.20 g/ml, i.e. in lysosomes. Chloroquine did not reduce the efficiency but delayed the secretion of pIgA into bile. Similarly, it did not affect the uptake of GalBSA but apparently delayed GalBSA transfer along successive populations of host organelles. The low density, GalBSA-containing structures were devoid of proteolytic activity. Anti-secretory components IgG and F(ab')2 were selectively excreted into bile, partially or totally as compounds of lower molecular mass. These antibody fragments probably result from a disulfide reduction activity along the pIgA pathway. In conclusion, our data (a) strongly suggest that pIgA and GalBSA are sorted between 3 min and 10 min after injection in non-lysosomal acidic organelles, (b) identify two successive and physically distinct endosomal populations containing GalBSA, and (c) provide the first evidence for a disulfide reduction activity along the transcytotic pathway of rat hepatocytes.

HEPATIC UPTAKE AND TRANSFER INTO BILE OF POLYMERIC IgA, ANTI‐SECRETORY COMPONENT IgG, HAPTOGLOBIN‐HEMOGLOBIN COMPLEX, GALACTOSYLATED SERUM ALBUMIN, AND HORSERADISH PEROXIDASE: A COMPARATIVE BIOCHEMICAL STUDY IN THE RAT

Annals of the New York Academy of SciencesVolume 409, Issue 1 p. 838-840 HEPATIC UPTAKE AND TRANSFER INTO BILE OF POLYMERIC IgA, ANTI-SECRETORY COMPONENT IgG, HAPTOGLOBIN-HEMOGLOBIN COMPLEX, GALACTOSYLATED SERUM ALBUMIN, AND HORSERADISH PEROXIDASE: A COMPARATIVE BIOCHEMICAL STUDY IN THE RAT J. N. Limet, J. N. Limet International Institute of Cellular and Molecular Pathology Brussels, BelgiumSearch for more papers by this authorJ. Quintart, J. Quintart International Institute of Cellular and Molecular Pathology Brussels, BelgiumSearch for more papers by this authorP. J. Courtoy, P. J. Courtoy International Institute of Cellular and Molecular Pathology Brussels, BelgiumSearch for more papers by this authorJ. P. Vaerman, J. P. Vaerman International Institute of Cellular and Molecular Pathology Brussels, BelgiumSearch for more papers by this authorY.-J. Schneider, Y.-J. Schneider International Institute of Cellular and Molecular Pathology Brussels, BelgiumSearch for more papers by this author J. N. Limet, J. N. Limet International Institute of Cellular and Molecular Pathology Brussels, BelgiumSearch for more papers by this authorJ. Quintart, J. Quintart International Institute of Cellular and Molecular Pathology Brussels, BelgiumSearch for more papers by this authorP. J. Courtoy, P. J. Courtoy International Institute of Cellular and Molecular Pathology Brussels, BelgiumSearch for more papers by this authorJ. P. Vaerman, J. P. Vaerman International Institute of Cellular and Molecular Pathology Brussels, BelgiumSearch for more papers by this authorY.-J. Schneider, Y.-J. Schneider International Institute of Cellular and Molecular Pathology Brussels, BelgiumSearch for more papers by this author First published: June 1983 https://doi.org/10.1111/j.1749-6632.1983.tb26944.xCitations: 7AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article.Citing Literature Volume409, Issue1The Secretory Immune SystemJune 1983Pages 838-840 RelatedInformation

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