Phagocytosis of ultrasound contrast agent microbubbles by Kupffer cells

Delayed parenchymal phase images of the liver more than 5 min after IV injection of ultrasound contrast agents are thought to be related to the phagocytosis of contrast agent microbubbles by macrophages. In this study, we examined whether liver-specific macrophages, Kupffer cells, phagocytosed the microbubbles and whether their elimination affected the delayed parenchymal images of the liver. Phase-contrast microscope observations showed that Kupffer cells phagocytosed various contrast agents in vitro. Among the contrast agents used, 99% of Sonazoid and Optison, and 47% of Levovist were phagocytosed, whereas only 7.3% of SonoVue and 0% of Imavist were phagocytosed. Elimination of Kupffer cells in vivo by gadolinium chloride (GdCl(3)) resulted in decreased intensity of the delayed parenchymal images with Sonazoid and Levovist, while SonoVue showed no changes compared with control. Our findings suggested that Kupffer cells phagocytosed contrast agents and they were responsible for the delayed images of contrast ultrasound in the liver.

Mechanism of hepatic parenchyma-specific contrast of microbubble-based contrast agent for ultrasonography: microscopic studies in rat liver

OBJECTIVE

The objective of this study was to elucidate the mechanism of hepatic parenchyma-specific contrast of Sonazoid (microbubble contrast agent) using microscopic techniques.

MATERIALS AND METHODS

Sonazoid was intravenously injected into rats to investigate the microbubble dynamics and distribution within hepatic microcirculation in exteriorized liver using intravital microscopy and to observe dose dependency of ultrasound hepatic contrast effect. In vitro and in vivo uptake of microbubbles by Kupffer cells was examined using confocal laser scanning microscopy.

RESULTS

Intravital observation demonstrated freely flowing microbubbles in the sinusoid and some microbubbles co-localized with Kupffer cells. The microbubbles internalized in Kupffer cells were identified with reflected light by confocal laser scanning microscopy. The percentage of Kupffer cells taking up microbubbles was about 1% at clinical dose at which the homogeneous hepatic contrast was observed.

CONCLUSIONS

The hepatic parenchyma-specific contrast by Sonazoid is due to distribution of the microbubbles in Kupffer cells.

Hepatic tumor detection: MR imaging and conventional US versus pulse-inversion harmonic US of NC100100 during its reticuloendothelial system-specific phase

PURPOSE

To compare conventional ultrasonography (US) and magnetic resonance (MR) imaging with contrast agent-enhanced US for detection of VX-2 liver tumors in rabbits.

MATERIALS AND METHODS

Conventional gray-scale liver US was performed in 65 rabbits, 38 of which had VX-2 hepatic tumor implants. Twenty minutes after contrast agent injection, gray-scale pulse-inversion harmonic US images of the liver-specific phase were obtained. Following sacrifice of the animals, T1- and T2-weighted MR imaging was performed at 4-mm intervals. Pathologic analysis was performed as the reference standard. The capability of each imaging modality to correctly depict tumor presence or absence and the number of tumors was compared.

RESULTS

Conventional US correctly depicted the presence or absence of tumors in 54 rabbits, for an accuracy of 83%, sensitivity of 71%, and specificity of 100%. With contrast-enhanced US, accuracy increased to 92% (60 correct cases); sensitivity, to 87%; and specificity, to 100%. MR imaging facilitated 56 correct diagnoses, for an accuracy of 86%, sensitivity of 82%, and specificity of 93%. There was a marginally significant difference between US with and US without contrast agent (P =.07) but not between MR imaging and contrast-enhanced US (P > or = .34). When the numbers of correctly detected tumors were compared, contrast-enhanced US performed significantly better than MR imaging (P =.02) and conventional US (P =.04).

CONCLUSION

There was no significant difference between contrast-enhanced US and MR imaging in the detection of hepatic tumors, whereas contrast-enhanced US had the highest accuracy (92%) of the three modalities studied.

Usefulness of contrast-enhanced intraoperative ultrasound using Sonazoid in patients with hepatocellular carcinoma

OBJECTIVE

To assess the usefulness of contrast-enhanced intraoperative ultrasound (CE-IOUS) using Sonazoid (gaseous perflubutane) in patients with hepatocellular carcinoma (HCC).

BACKGROUND

Contrast-enhanced intraoperative ultrasound using Sonazoid, a novel ultrasonic contrast agent enabling Kupffer imaging, may enable differentiation of HCC among new focal liver lesions found during fundamental intraoperative ultrasound (fundamental-NFLLs).

METHODS

Between February 2007 and February 2009, a total of 192 consecutive patients were enrolled. Fundamental intraoperative ultrasound and CE-IOUS were performed successively after laparotomy. The vascularity of 1 representative lesion was examined in harmonic mode for approximately 1 minute after the intravenous injection of Sonazoid (vascular phase). Approximately 15 minutes after the vascular phase, total liver scanning in the harmonic mode was commenced (Kupffer phase). One additional injection of Sonazoid was allowed to examine the vascularity of another lesion, if necessary. A tentative diagnosis of HCC was made when a lesion was either hypervascular during the vascular phase or hypoechoic during the Kupffer phase. A final diagnosis of HCC was made on the basis of the results of a histological examination or dynamic computed tomography findings obtained during the 12-month postoperative period.

RESULTS

Seventy-nine fundamental-NFLLs were found in 50 patients (26%), 17 (22%) of which were finally diagnosed as HCC. The sensitivity, specificity, and accuracy of CE-IOUS for differentiating HCC among fundamental-NFLLs were 65%, 94%, and 87%, respectively. Contrast-enhanced intraoperative ultrasound identified 21 additional new hypoechoic lesions in 16 patients, of which 14 lesions (67%) in 11 patients were finally diagnosed as HCC. This prospective study protocol was approved by the institutional review board of the Tokyo University Hospital. An English-language summary of the protocol was submitted (registration ID: UMIN000003046) to the Clinical Trials Registry managed by the University Hospital Medical Information Network in Japan (http://www.umin.ac.jp/ctr/index.htm).

CONCLUSIONS

With help of CE-IOUS using Sonazoid, more accurate intraoperative staging for HCC can be performed.

Definition of contrast enhancement phases of the liver using a perfluoro-based microbubble agent, perflubutane microbubbles

To define the contrast enhancement phases in the liver with perflubutane microbubbles, the liver enhancement time-intensity curves were investigated in 14 healthy volunteers. The agent was injected intravenously as a bolus and the liver was imaged with an ultrasound scanner as long as 4h after the injection. Time-intensity curves from the hepatic artery, the intrahepatic portal vein, the hepatic vein and the parenchyma of the liver were obtained from the liver ultrasound images. The arrival of the agent in the hepatic artery, the portal vein and the hepatic vein were visually distinguishable and the mean arrival times were 19.2, 24.3 and 32.2 s after the injection, respectively. The signal intensity in these vessels increased rapidly after the arrival of the contrast and gradually reverted to baseline after the peak. In contrast, within 5 min after the injection, the intensity in the parenchyma increased and reached a plateau, which persisted for at least 2h. The contrast enhancement phases in the liver with perflubutane microbubbles could be defined as two major phases-a vascular phase, in which the vessels are enhanced between 15 s and 10 min after injection, and a Kupffer phase, in which the parenchyma is enhanced 10 min after injection. The vascular phase is divided into three subphases: the arterial phase (15 to 45 s after injection); the portal phase (45 s to 1 min after injection); and the vasculo-Kupffer phase (1 to 10 min after injection).

Real-time contrast-enhanced sonographically guided biopsy or radiofrequency ablation of focal liver lesions using perflurobutane microbubbles (sonazoid): value of Kupffer-phase imaging

OBJECTIVES

To evaluate the utility of Kupffer-phase imaging by real-time contrast-enhanced sonography using the perflurobutane microbubble contrast agent Sonazoid (GE Healthcare, Oslo, Norway) in guiding biopsy or radiofrequency (RF) ablation of focal liver lesions.

METHODS

A total of 75 patients (mean age, 59.7 years) who were referred for percutaneous biopsy (n = 42) or RF ablation (n = 33) were included in the study. Grayscale sonography and contrast-enhanced sonography using Sonazoid were performed in all patients before the procedure. The conspicuity of each targeted liver lesion on grayscale sonography, vascular-phase contrast-enhanced sonography, and Kupffer-phase contrast-enhanced sonography was graded using a 5-point scale. Lesion detection rates were calculated, and the conspicuity of the lesions among the imaging modalities was compared. The technical success of the procedures was also assessed.

RESULTS

The procedures were conducted in 66 patients (biopsy in 41 and RF ablation in 25) under real-time guidance by Kupffer-phase contrast-enhanced sonography. Lesion detection rates were 77.3% (58 of 75), 84.0% (63 of 75), and 92.0% (69 of 75) on grayscale sonography, vascular-phase contrast-enhanced sonography, and Kupffer-phase contrast-enhanced sonography, respectively, and were significantly different among the 3 modalities (P= .034). Overall, lesion conspicuity was significantly increased on vascular-phase and Kupffer-phase contrast-enhanced sonography compared to grayscale sonography (P < .001). Technical success rates for the procedures were 95.2% (40 of 42) for biopsy and 69.7% (23 of 33) for RF ablation.

CONCLUSIONS

Kupffer-phase imaging by contrast-enhanced sonography using Sonazoid increases the conspicuity of the liver lesions compared to grayscale sonography, and it is useful for real-time guidance of percutaneous biopsy or RF ablation of focal liver lesions.

New malignant grading system for hepatocellular carcinoma using the Sonazoid contrast agent for ultrasonography

BACKGROUND

The ultrasonography contrast agent Sonazoid provides parenchyma-specific contrast imaging (Kupffer imaging) based on its accumulation in Kupffer cells. This agent also facilitates imaging of the fine vascular architecture in tumors through maximum intensity projection (MIP). We examined the clinical utility of the malignancy grading system for hepatocellular carcinoma (HCC) using a combination of 2 different contrast-enhanced ultrasonography images.

METHODS

We studied 121 histologically confirmed cases of HCC (well-differentiated, 45; moderately differentiated, 70; poorly differentiated, 6). The results of Kupffer imaging were classified as (1) iso-echoic pattern or (2) hypo-echoic pattern. The MIP patterns produced were classified into one of the following categories: fine, tumor vessels were not clearly visualized and only fine vessels were visualized; vascular, tumor vessels were visualized clearly; irregular, tumor vessels were thick and irregular. Based on the combined assessment of Kupffer imaging and the MIP pattern, the samples were classified into 4 grades: Grade 1 (iso-fine/vascular), Grade 2 (hypo-fine), Grade 3 (hypo-vascular), and Grade 4 (hypo-irregular).

RESULTS

The distribution of moderately and poorly differentiated HCCs was as follows: Grade 1, 4 % (1/24); Grade 2, 52 % (15/29); Grade 3, 85 % (44/52); and Grade 4, 100 % (16/16). The grading system also predicted portal vein invasion in 72 resected HCCs: Grade 1, 0 % (0/4); Grade 2, 13 % (1/8); Grade 3, 23 % (11/48); and Grade 4, 67 % (8/12).

CONCLUSIONS

This new malignant grading system is useful for estimation of histological differentiation and portal vein invasion of HCC.

Kupffer cells in hepatocellular adenomas

Hepatocellular adenomas are usually visualized as defects on technetium-99m-sulfur colloid liver scans, a fact which has been attributed to the absence of phagocytic Kupffer cells in the tumors. To determine whether this is true, seven hepatocellular adenomas were subjected to immunoperoxidase staining for lysozyme, a marker of mononuclear phagocytes. The Kupffer cells were counted in the tumors and surrounding non-neoplastic liver. All hepatocellular adenomas studied were found to contain Kupffer cells. Three tumors had fewer Kupffer cells than the surrounding liver. Three had about the same number as the surrounding liver, and one had more Kupffer cells than the non-neoplastic liver. Thus, the lack of phagocytosis of colloid in liver scans is probably due to something other than a deficiency of Kupffer cells in the hepatocellular adenomas.

Kupffer phase image of Sonazoid-enhanced US is useful in predicting a hypervascularization of non-hypervascular hypointense hepatic lesions detected on Gd-EOB-DTPA-enhanced MRI: a multicenter retrospective study

BACKGROUND

It remains unknown whether Kupffer-phase images in Sonazoid-enhanced ultrasonography (US) can be used to predict hypervascularization of borderline lesions. Therefore, we aimed to clarify whether Kupffer-phase images in Sonazoid-enhanced ultrasonography can predict subsequent hypervascularization in hypovascular borderline lesions detected on hepatobiliary-phase gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging.

METHODS

From January 2008 to March 2012, 616 low-intensity hypovascular nodules were detected in hepatobiliary-phase images of Gd-EOB-DTPA-enhanced MRI at nine institutions. Among these, 167 nodules, which were confirmed as hypovascular by Gd-EOB-DTPA-enhanced MRI and Sonazoid-enhanced US, were evaluated in this study. Potential hypervascularization factors were selected based on their clinical significance and the results of previous reports. The Kaplan-Meier model and log-rank test were used for univariate analysis and the Cox regression model was used for multivariate analysis.

RESULTS

The cumulative incidence of hypervascularization of borderline lesions was 18, 37, and 43 % at 1, 2, and 3 years, respectively. Univariate analyses showed that tumor size (p = 0.0012) and hypoperfusion on Kupffer-phase images in Sonazoid-enhanced US (p = 0.004) were associated with hypervascularization of the tumor. Multivariate analysis showed that tumor size [HR: 1.086, 95 % confidence interval = 1.027-1.148, p = 0.004] and hypo perfusion on Kupffer-phase images [HR: 3.684, 95 % confidence interval = 1.798-7.546, p = 0.0004] were significantly different.

CONCLUSIONS

Kupffer-phase images in Sonazoid-enhanced US and tumor diameter can predict hypervascularization of hypointense borderline lesions detected on hepatobiliary-phase Gd-EOB-DTPA-enhanced MRI.

Differential receptor targeting of liver cells using 99mTc-neoglycosylated human serum albumins

Neolactosyl human serum albumin (LSA) targets asialoglycoprotein receptor and shows high liver uptake due to accumulation in hepatocytes. Although neomannosyl human serum albumin (MSA) also shows high liver uptake, it has been reported to be taken up by Kupffer cells and endothelial cells. We compared the biological properties of LSA and MSA. 99mTc-LSA and 99mTc-MSA biodistribution in mice were investigated after intravenous injection. In vivo localization of rhodaminisothiocyanate (RITC)-LSA and fluoresceineisothiocyanate (FITC)-MSA were investigated in mouse liver. Excretion routes of 99mTc-LSA and 99mTc-MSA metabolites were examined. Both 99mTc-LSA and 99mTc-MSA showed high liver uptakes. RITC-LSA was taken up by hepatocytes whereas FITC-MSA was taken up by Kupffer cells and endothelial cells. 99mTc-MSA showed higher spleen and kidney uptakes than 99mTc-LSA. 99mTc-LSA metabolites excreted in urine and feces accounted for 44.4 and 50.0% of 99mTc-LSA injected, respectively, while 99mTc-MSA metabolites accounted for 51.5 and 10.3%, respectively. In conclusion, LSA is specifically taken up by hepatcytes while MSA by Kupffer cells and endothelial cells. After taken up by the liver, LSA is metabolized by the hepatocytes and then excreted through both the hepatobiliary tract and kidney, whereas MSA is metabolized by Kupffer cells and endoghelial cells and then excreted mainly through the kidney.

The use of human albumin millimicrospheres tagged with 99mTc in the evaluation of the removal capacity of the reticuloendothelial system

Liver uptake kinetics of 99mTc labelled millimicrospheres of human serum albumin (MM) was studied in 16 subjects. Every subject received four doses of MM intravenously. The uptake constant decreased progressively with increasing dose. The maximum liver removal capacity, a parameter which is independent of liver blood flow, was calculated according to the method of Iio and Wagner (1963). From these data we conclude that MM are taken up by the reticuloendothelial system (RES) with saturable kinetics, and they are suitable for clinical use to evaluate RES function in man.

Diagnosis of hepatocellular carcinoma nodules in patients with chronic liver disease using contrast-enhanced sonography: usefulness of the combination of arterial- and kupffer-phase enhancement patterns

OBJECTIVES

To determine the usefulness of contrast-enhanced sonography using the perfluorobutane contrast agent Sonazoid (Daiichi-Sankyo, Tokyo, Japan) for establishing the diagnosis and cellular differentiation of hepatocellular carcinoma in patients with chronic liver disease.

METHODS

Patients with chronic liver disease in whom hepatic nodules were detected during screening for hepatocellular carcinoma were examined by imaging modalities, including contrast-enhanced computed tomography (CT), contrast-enhanced sonography, and contrast-enhanced magnetic resonance imaging. Nodules with negative imaging findings were further investigated with core biopsy or followed at our hospital. Between April 2007 and March 2011, all patients with hepatic nodules who underwent core biopsy of the nodules or hepatic resection for hepatocellular carcinoma were reviewed. Fifty-nine nodules from 47 patients with 42 contrast-enhanced sonographic findings and 41 contrast-enhanced CT findings were examined. Arterial- and Kupffer-phase enhancement patterns of the nodules on contrast-enhanced sonography were compared with the diagnosis and cellular differentiation of hepatocellular carcinoma. Arterial- and late-phase enhancement patterns on contrast-enhanced CT were also compared with histologic findings.

RESULTS

The combination of hyperenhancement in the arterial phase and hypoenhancement in the Kupffer phase on contrast-enhanced sonography (n = 11) correlated with moderately differentiated hepatocellular carcinoma (P = .0028, Fisher exact test). The combination of hypoenhancement in the arterial phase and isoenhancement in the Kupffer phase on contrast-enhanced sonography (n = 14) correlated with well-differentiated hepatocellular carcinoma (P = .0006, Fisher exact test). The combination of high density in the arterial phase and low density in the late phase on contrast-enhanced CT (n = 21) correlated with moderately differentiated hepatocellular carcinoma (P = .0059, Fisher exact test), but no enhancement pattern combination on contrast-enhanced CT correlated with well-differentiated hepatocellular carcinoma.

CONCLUSIONS

Sonazoid contrast-enhanced sonography is useful for diagnosis of well-differentiated hepatocellular carcinoma.

Phagocytosis and dynamic RES scintigraphy: an evaluation of commercial colloids in rats

Reticuloendothelial system (RES) phagocytic function or capacity can be measured by clearance studies with test substances. This study in the rat examines three commercially available 99Tcm-labelled test substances, and different methods of calculating RES capacity. Albures size 500 nm and sulphur colloid size 600 nm used for liver scintigraphic imaging and Nanocoll size 50 nm used for bone-marrow scintigraphic imaging were tested. The rats were examined under a gamma camera and the uptake by the liver, clearance from the heart and clearance from blood samples were recorded. Different amounts of substances were tested. The final uptake in different organs was recorded after the animals were sacrificed. Colloid size and stability were tested with a polycarbonate filter. (Nanocoll was found to have at least 10 times smaller colloid diameter, leading to a thousand times more particles per milligram). RES function was calculated as the uptake rate or clearance rate, k. In a logarithmic plot, the relationship between uptake or clearance and time was found to be linear between 90 and 300s and calculations of k in this interval are recommended. k-values selected from blood sample curves were 11 +/- 5 S.E.M. lower than those calculated from heart clearance curves or liver uptake curves. Increasing amounts of Nanocoll caused a decrease in uptake rate k. Albures and sulphur colloid could not be given in amounts that caused any change in k. Only Nanocoll could be given in sufficiently large amounts (above the critical dose) to challenge RES and avoid complete extraction from the circulation during first passage through RE organs. Nanocoll seems suitable for use in tests of RES function and the optimal amount was 0.03 mg per rat (0.6 X 10(12) particles).

Kupffer Imaging by Contrast-Enhanced Sonography With Perfluorobutane Microbubbles Is Associated With Outcomes After Radiofrequency Ablation of Hepatocellular Carcinoma

OBJECTIVES

An ultrasound contrast agent consisting of perfluorobutane microbubbles (Sonazoid; Daiichi Sankyo, Tokyo, Japan) accumulates in Kupffer cells, which thus enables Kupffer imaging. This study aimed to elucidate the association of defect patterns of hepatocellular carcinoma during the Kupffer phase of Sonazoid contrast-enhanced sonography with outcomes after radiofrequency ablation (RFA).

METHODS

For this study, 226 patients with initial hypervascular hepatocellular carcinoma, who could be evaluated by contrast-enhanced sonography with Sonazoid before RFA, were analyzed. Patients were divided into 2 groups according to the tumor defect pattern during the Kupffer phase. The irregular-defect group was defined as patients with hepatocellular carcinoma that had a defect with an irregular margin, and the no-irregular-defect group was defined as patients with hepatocellular carcinoma that had either a defect with a smooth margin or no defect. Critical recurrence was defined as more than 3 intrahepatic recurrences, vascular invasion, dissemination, or metastasis.

RESULTS

The irregular-defect and no-irregular-defect groups included 86 and 140 patients, respectively, and had cumulative 5-year critical recurrence rates of 49% and 17% (P < .01). Multivariate analysis indicated that the tumor diameter, lens culinaris agglutinin- reactive α-fetoprotein level, and defect pattern were independent factors related to critical recurrence. The cumulative 5-year overall survival rates for the irregular-defect and no-irregular-defect groups were 46% and 61% (P< .01). Multivariate analysis indicated that the Child-Pugh class, tumor diameter, lens culinaris agglutinin-reactive α-fetoprotein level, and defect pattern were independent factors related to survival.

CONCLUSIONS

The defect pattern of hepatocellular carcinoma during the Kupffer phase of Sonazoid contrast-enhanced sonography is associated with critical recurrence and survival after RFA.

Transient liver accumulation of Tc-99m phytate in hepatocellular carcinoma after percutaneous ethanol injection

PURPOSE

We report that colloid liver scanning gave early evidence of the return to normal of Kupffer cell functions after ethanol injections into the liver.

PATIENT AND METHODS

A 71-year-old man with hepatocellular carcinoma received percutaneous ethanol injections twice of 15 mL of ethanol, 1 week apart.

RESULTS

Abdominal CT after the second injection showed an irregularly shaped low-density area in the left side of the tumor, extending outside the tumor. Liver imaging with To-99m phytate 10 days later showed increased activity at the corresponding site. Thirty days after the second injection, liver imaging did not show high activity.

CONCLUSIONS

Ethanol that leaked into the normal part of the liver probably temporarily activated Kupffer cell function.

Binding cells of 125I-iodoamphetamine in rat liver

We recently reported that transrectal or intestinal portal scintigraphy with 123I-iodoamphetamine (IMP) could be a useful method for the non-invasive and quantitative evaluation of the portosystemic shunt in portal hypertension, but what cells in the liver trap IMP has not been clarified. This study was aimed at elucidating whether IMP was extracted by parenchymal cells, sinusoidal endothelial cells, Kupffer cells or fat storing cells. Each type of liver cell was isolated from rats and cultured. The cells were incubated with 125I-IMP and the radioactivity of the lysate was determined. Nonspecific binding was assessed in the presence of an excess of unlabeled IMP, and specific binding was determined by subtracting the nonspecific from total binding. Specific binding observed in parenchymal cells, endothelial cells and Kupffer cells was 70.2 +/- 0.4, 4.2 +/- 1.4 and 2.3 +/- 0.8 pmol/well, respectively, but no specific binding was observed in fat storing cells. The binding in parenchymal cells was much higher than that in endothelial cells or Kupffer cells (p < 0.005). In addition, the binding to parenchymal cells reached equilibrium within 20 min and was not saturable over the concentration range tested (0.5-10 microM). These findings indicate that IMP is mostly extracted by parenchymal cells in the liver.

Experimental study of iron effect on the liver function

The effect of iron on the liver function was studied in rats. A total of 40 rats were divided into four groups. Group 1 was given iron; Group 2, carbon tetrachloride; Group 3, a combination of iron and carbon tetrachloride; and Group 4 was the control. The changes in liver function were evaluated by using hepatobiliary and liver scintigraphy as the index of hepatocyte function and reticuloendothelial system function, respectively. Determination of liver CT number and a histological study were made at the same time. The administration of iron activated the reticuloendothelial system function per unit of liver weight. However, because of the decrease in liver weight, the total reticuloendothelial system function did not change at all. In the group given iron and carbon tetrachloride, liver cirrhosis and siderosis in the reticuloendothelial system occurred. Dysfunction in the reticuloendothelial system was more severe in this group than in the group given carbon tetrachloride only, by hepatocyte dysfunction was more mild. It is doubtful that the administration of iron after liver dysfunction had developed, which caused acceleration of fibrosis and reduction of liver blood flow, led to the enhancement of the reticuloendothelial system dysfunction.

Portal hyperfusion or hepatic venous congestion: which one affects Kupffer cell function more?

OBJECTIVES

Because of their effects on the liver parenchyma after surgery, portal hyperperfusion and hepatic venous congestion are challenging problems for hepatobiliary surgeons. However, the effects of those conditions on Kupffer cells have not been established. The aim of this study was to investigate the effects of vascular streams modified by portal hyperperfusion and hepatic venous congestion on Kupffer cell function.

MATERIALS AND METHODS

Thirty rats were allocated into 3 groups of 10 rats each and were subjected to right portal vein ligation to induce hyperperfusion in the left lobe of the liver (group 1), occlusion of the right hepatic vein to produce venous congestion (group 2), or sham operation (controls; group 3). After 72 hours, the right and left liver lobes of the subjects were submitted separately for scintigraphic and histopathologic evaluation, and the radiocolloid uptake per gram of liver tissue and the number of Kupffer cells per square millimeter were calculated.

RESULTS

The mean technetium-99m labeled sulfur colloid uptake values of the liver tissue per gram were 0.126 -/+ 0.038 for group 1, 0.106 -/+ 0.032 for group 2, and 0.110 -/+ 0.031 for group 3. Portal hyperperfusion significantly increased the technetium-99m labeled sulfur colloid uptake of the liver tissue per gram (P = .043). The mean number of Kupffer cells per square millimeter was calculated for each group as follows: 321 -/+ 094 x 10-6 for group 1, 369 -/+ 083 x 10-6 for group 2, and 355 -/+ 096 x 10-6 for group 3. Both vascular streams produced no significant effects on the number of Kupffer cells (P > .05).

CONCLUSIONS

In this experimental model, portal hyperperfusion affected Kupffer cell function more than did hepatic venous congestion.

Spleen/liver ratio in RES-scintigraphy. A comparison between posterior registration and emission computed tomography

The relative uptake of the spleen compared with the liver in RES-scintigraphy is of diagnostic significance. The spleen/liver (S/L) ratio from a posterior registration is most often used. The high S/L ratios found in earlier reports could well be explained by splenomegaly. Posterior registration as well as emission computed tomography was performed in 29 patients. In cases with splenomegaly the S/L ratio derived from the posterior registration was about the same as from emission computed tomography. In cases without splenomegaly the S/L ratios found by emission computed tomography were significantly higher and more correct than the values recorded from a posterior registration.

In vivo assessment of phagocytic properties of Kupffer cells

Three-compartment analysis was used to assess the kinetics of phagocytosis of Tc-99m-labeled human serum albumin microparticles (Tc-99m HSA-MM) in human Kupffer cells in vivo. The tracer turnover in these phagocytic cells could be described by a monoexponential accumulation with a two-stage elimination phase. Three-compartment analysis of the Tc-99m HSA-MM kinetics allowed us to quantify tracer attachment, phagocytosis, and degradation in Kupffer cells. The calculated time course of phagocytosis in ten control subjects proved to be identical to that of phagocytosis of various test substances in mouse macrophage monolayers (1). In addition, an impairment of particle turnover at the macrophage membrane, a significantly diminished (p less than 0.01) phagocytosis rate of the tracer, was observed in ten patients with various tumors.

A detailed examination of pulmonary uptake of (99m)Tc-Tin colloid in healthy mature miniature pigs

(99m)Tc-Tin colloid is a commonly used colloidal radiopharmaceutical in human medicine for evaluating liver function and morphology. (99m)Tc-Tin colloid is taken up in the liver by the phagocytic activity of Kupffer cells, the reticuloendothelial cells of the liver. Unlike what occurs in human beings, we demonstrated (99m)Tc-Tin colloid uptake within the lungs and liver in healthy, mature, miniature pigs. Our observations may be explained by the presence of pulmonary intravascular macrophages (PIMs) closely apposed to the endothelium of the pulmonary capillaries in several animal species, such as the sheep, horse, goat, cat and pig. In the current study, we compared scintigraphic images using (99m)Tc-Tin colloid in rats with those in mature, miniature pigs, and identified the presence of PIMs, reticuloentothelial cells similar to Kupffer cells, by immunohistochemistry in pigs. Pulmonary uptake of (99m)Tc-Tin colloid occurred only in pigs, and PIMs in the pulmonary capillaries stained positively for mouse monoclonal MAC387 antibodies to macrophages in lung sections, as well as Kupffer cells in liver sections. Therefore, we conclude that the uptake of intravenously injected (99m)Tc-Tin colloid within both Kupffer cells and PIMs results in scintigraphic imaging of the lung and liver in miniature pigs.

[Reticulohistiocyte system activity of the liver in patients with nephrotuberculosis]

The reticuloendothelial system of the liver was studied in 27 patients with nephrotuberculosis by means of radionuclide hepatography with colloid solution of Au-198. It was found that all these patients showed a reduction of the activity of stellate reticuloendotheliocytes of the liver. These conclusions were made on the basis of distinctly changed values of the period of half-purification of the blood, constants of blood purification, coefficient of liver retention, etc. There was also a distinct reduction of fractional blood flow of the liver.