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Effects of long-chain triglyceride emulsions on reticuloendothelial system function in humans.

Parenteral administration of long-chain triglyceride emulsions has been shown to have deleterious effects on reticuloendothelial system function in animal models. It is unknown whether this interference occurs in humans with clinically relevant doses of intravenous fat. Two studies were done. Eighteen patients were prospectively enrolled for study. Patients received full feeding by continuous total parenteral nutrition (amino acids 1.5 g/kg/day and dextrose 4.5 g/kg/day) with 33.1 kcal/kg/day. Forty-three % of the nonprotein calories were provided as soybean oil emulsion (Travamulsion 20%) and was administered intravenously over 10 hr (0.130 g/kg/hr). Reticuloendothelial system function was determined by measuring the change in the clearance rate of intravenously injected 99mTc-sulfur colloid (TSC) in each patient. In study 1 (n = 10), one day of lipid (10 hr) was infused, with the clearance of 99mTc-sulfur colloid measured before the lipid was infused and then during the last hour of the 10-hr infusion. In study 2 (n = 8), the clearance rates were measured before the lipid emulsion was begun, and then during the last hour of the infusion on the 3rd day. Clearance rates for TSC after 10 hr of lipid infusion in study 1 did not differ (0.27 +/- 1/min to 0.26 +/- 0.1/min, p greater than 0.10). However, after 3 days of lipid infusion (10 hr/day), a statistically significant reduction in TSC was seen (0.46 +/- 0.08/min-0.27 +/- 0.03/min, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1980

Enhanced phagocytosis and bactericidal activity of hepatic reticuloendothelial system during endotoxin tolerance.

The effects of tolerance to Escherichia coli endotoxin on the phagocytic and bactericidal activity of the hepatic reticuloendothelial system against viable E. coli were examined using ex vivo perfused rat livers. Livers were isolated from control and endotoxin-tolerant rats and perfused with a medium containing 5% homologous serum from either control or tolerant rats. After the addition of the E. coli (2 x 10(7) cells per ml) to the perfusate, the hepatic clearance of the bacteria was followed for 30 min. The highest activation of the hepatic reticuloendothelial system was observed when serum from tolerant animals was added to the perfusate. Under these conditions phagocytosis was 47% (12% in controls), and 37 to 38% of the bacteria were killed (5% in controls). This activation was less when livers obtained from tolerant rats were perfused with serum from controls or with saline only. The data suggests that, during endotoxin tolerance, humoral factors play an important role in the activation of the hepatic reticulendothelial system, although a direct stimulation of Kupffer cells also occurs. The enhancement of phagocytosis by tolerant serum did not require the presence of homologous antibodies and involved the activation of the alternative complement pathway, since it was lost after removal of factor B activity. On the other hand, stimulation of intracellular killing required both complement and specific antibodies. The data suggest a role of endotoxin in the activation of humoral and cellular mechanisms involved in the host resistance to gram-negative bacterial infection.

Animals↗
PubMed1984

Reticuloendothelial system response to hyperlipidemia in rhesus and cynomolgus monkeys.

A detailed study of the effect of various periods of hyperlipidemia on the reticuloendothelial system (RES) lipid accumulation in rhesus and cynomolgus monkeys was conducted. The cynomolgus serum cholesterol and triglyceride levels were on the average more elevated than the rhesus levels throughout a 12-month period when both species were fed a diet containing 12.5% coconut oil, 12.5% butter fat, and 2% cholesterol. After cynomolgus monkeys were fed this diet, their reticuloendothelial system became more lipid laden than that of the rhesus monkeys, in both the liver and the spleen. This was also true for the circulating monocytes. Furthermore, the parenchymal cells of the cynomolgus livers also become more fat filled, and chemical analyses demonstrated more cholesterol (total, free, and esterified) and triglycerides in the liver and the spleen. Xanthomata development in the cynomolgus, although similar in type and distribution, was more extensive than that in the rhesus monkey after similar periods of experimental diet feeding. Therefore, the RES of two species of macaque monkeys are affected differently when challenged with the same high fat, high cholesterol diet, with the cynomolgus RES being much more involved with lipid and cholesterol storage than the rhesus RES.

Animals↗
PubMed1982

Modulation of hepatic reticuloendothelial system phagocytosis by pancreatic hormones.

Experiments were conducted to determine the influence of the pancreatic hormones insulin, glucagon, and somatostatin on reticuloendothelial system (RES) phagocytosis both in vivo and in the isolated perfused livers of rats. Chronic pancreatic hormonal treatment consisted of twice daily injections SC of NPH insulin with doses ranging from 0.75 U on day 1 to 9.0 U on day 13 and unchanged doses of glucagon (200 micrograms) and somatostatin (50 micrograms). Chronic treatment with insulin significantly depressed by 48% intravascular phagocytosis of colloidal carbon administered IV at a dose of 8 mg/100 g, while glucagon and somatostatin stimulated macrophage endocytic function by 32% and 26%, respectively, compared to the control value. Acute treatment with the three pancreatic hormones at 30 min prior to carbon administration similarly produced insulin depression as well as glucagon and somatostatin stimulation of RES phagocytosis. Addition of the three hormones at near physiologic concentrations (20 ng/ml for insulin, 10 ng/ml for glucagon, and 5 ng/ml for somatostatin) to the recirculating perfusate of isolated perfused rat livers simultaneous with 24 mg of colloidal carbon likewise resulted in phagocytic reduction after insulin and enhancement after glucagon and somatostatin. Experiments involving insulin in vitro with isolated perfused livers as well as glucose replacement therapy concomitant with insulin in vivo demonstrated that hypoglycemia is not necessary for phagocytic depression by insulin while severe hypoglycemia in the perfusion medium is sufficient to depress carbon uptake by isolated perfused livers independent of insulin. Both pancreatic hormones and the level of glycemia seem to be important in modulating hepatic reticuloendothelial system phagocytosis.

Animals↗
PubMed1985

The use of erythrocytes for delivery of chemotherapeutic agents to the reticuloendothelial system.

The object of our work is to define the possible role of hypotonically loaded erythrocytes as carriers to target drugs to the reticuloendothelial system. We have examined choices of drugs for loading into the erythrocytes and have considered methods of altering potentially useful agents so that they will load. We have demonstrated that the delivery of bleomycin to the reticuloendothelial system of mice, inside erythrocyte carriers, potentiates the effect of this drug on phagocytosis. We speculate, that this targeted delivery of bleomycin to phagocytes could be beneficial in the treatment of diseases characterized by an important phagocytic component.

Animals↗
PubMed1990

[Pharmacological study on Agkistrodon blomhoffii blomhoffii Boie. II. Effect of 50% ethanolic extract on phagocytic activity of mouse reticuloendothelial system].

Effect of a 50% ethanolic extract ([M]) from dried whole body of Agkistrodon blomhoffii blomhoffii Boie on a phagocytic activity of reticuloendothelial system was studied by the carbon clearance method in mice. The clearance-rate of carbon was significantly shortened 1 h after the oral administration of [M] (250 or 500 mg/kg, one time/d for 3d). [M] activated the phagocytosis of carbon by macrophage (M phi) in the spleen and the phagocytosis of latex by peritoneal M phi. These results suggested that [M] may promote the phagocytic activity on the reticuloendothelial system in mice and has a stimulatory effect on M phi.

Animals↗
PubMed1984

Effects of long-term combination chemotherapy on the reticuloendothelial system.

The phagocytic and metabolic functions of the reticuloendothelial system (RES) were studied in 20 postoperative cancer patients undergoing long-term combination chemotherapy. Each course included vincristine, methyl-CCNU (day 1) and 5-fluorouracil (days 1-5) every sixth week. The RES-test was performed prior to each course, using 125I-labeled microaggregated human serum albumin. Total leukocytes, mononuclear cells and platelets were monitored before, during and after each treatment. A significant, initial impairment of the catabolic function of the RES was found (2P = 0.006). A similar, nonsignificant trend was observed in the phagocytic function. The normalization may mirror the large metabolic capacity of the RES. This is further demonstrated by the fact that splenectomized (N = 9) and nonsplenectomized patients did not differ. A significant decrease was also found in total leukocytes and mononuclear cells (2P less than 0.001). Combination chemotherapy induced a similar myelosuppression in both groups, but did not further reduce the mobile RES in asplenic individuals.

Adult↗
PubMed1998

Serum-mediated recognition of liposomes by phagocytic cells of the reticuloendothelial system - The concept of tissue specificity.

The mechanisms responsible for the clearance and recognition of intravenously injected liposomes by phagocytic cells of the reticuloendothelial system are presently not well understood. Here, we address a multiplicity of physicochemical and physiopathological factors which influence the clearance kinetics and tissue distribution of liposomes administered into the circulation. Emphasis is particularly drawn towards the concept of liposome-blood protein interaction and its role in liposome recognition by various phagocytes of the reticuloendothelial system.

Journal Article↗
PubMed1981

An immunohistologic study of Shope fibroma virus in rabbits: tumor rejection by cellular reaction in adults and progressive systemic reticuloendothelial infection in neonates.

The development of lesions in adult and neonatal New Zealand White rabbits following intradermal inoculation of Shope fibroma virus was studied by immunofluorescence for viral antigens. T-cells, and immunoglobulin. In adults a self-limiting local fibroxanthosarcomatous tumor was rejected within 10-12 days in association with a dense infiltration of T-cells. In neonates expanding skin lesions were associated with systemic presence of virus in the reticuloendothelial system. In surviving infected neonates, granulomas formed at the site of infection after 3 weeks. These reactions may have limited further dissemination of the virus. These results support the hypothesis that the progressive disease produced by Shope fibroma virus in neonatal rabbits may be due to the inability of the reticuloendothelial system to clear infectious virus.

Animals↗
PubMed1983

Reticuloendothelial system fc receptor function in rheumatoid arthritis.

Patients with systemic lupus erythematosus (SLE) have abnormal reticuloendothelial system (RES) IgG Fc receptor function which is correlated with disease activity and levels of immune complexes (IC). We studied RES function, IC levels, clinical and laboratory manifestations in 43 patients with RA. The articular index was abnormal in 42 patients (range of 6 to 153). Thirty were seropositive; 31 had an elevated erythrocyte sedimentation rate. Extraarticular manifestations included nodules (25), anemia (19), Sjögren's syndrome (6), vasculitis (4), and Felty's syndrome (2). Medication included corticosteroids (32), nonsteroidal antiinflammatory drugs (33), slow acting antirheumatic drugs (18), and cytotoxics (2). Thirty-three patients had IC (30 by the Clq binding assay, 21 by the Raji cell assay); 13 patients had normal RES function (t 1/2-24-60 min; upper 95% confidence limit in normals = 62 min). Thirty had prolonged clearance times (65-210 min, mean 106 min). In contrast to SLE, clearance times were not found to be correlated with IC levels, or clinical or laboratory measures of disease activity. Defective RES immune clearance may not be an important determinant in the pathogenesis of immunologic tissue damage in rheumatoid arthritis.

Adult↗
PubMed1987

19F magnetic resonance imaging of the reticuloendothelial system.

In this study sequential 1H and 19F magnetic resonance imaging methods were used to map the distribution of fluorinated compounds in vivo. An intravenously administered emulsion of perfluorooctylbromide (PFOB), an agent known to localize in the reticuloendothelial system, was detected in the liver and spleen of all studied hamsters and mice using 19F MRI. Lungs and salivary glands were also affected in some animals. Using a G. E. NMR CSI 2-T spectroscopy/imaging system, projection 19F images were obtained in 4 to 8 min. Subsequent mouse studies using a thick-slice driven equilibrium pulse sequence produced 19F images with an improved signal-to-noise ratio in a shorter acquisition time. With PFOB, 19F MRI has the capability of detecting macrophages in the reticulo-endothelial system and in other sites where macrophages congregate. This is the first report where the reticuloendothelial system was specifically imaged in live animals and where driven equilibrium imaging techniques have been applied to 19F MRI.

Animals↗
PubMed2003

Iron metabolism in the reticuloendothelial system.

Comprised mainly of monocytes and tissue macrophages, the reticuloendothelial system (RES) plays two major roles in iron metabolism: it recycles iron from senescent red blood cells and it serves as a large storage depot for excess iron. Although iron recycling by the RES represents the largest pathway of iron efflux in the body, the precise mechanisms involved have remained elusive. However, studies characterizing the function and regulation of Nramp1, DMT1, HFE, FPN1, CD163, and hepcidin are rapidly expanding our knowledge of the molecular aspects of RE iron handling. This review summarizes fundamental physiological and biochemical aspects of iron metabolism in the RES and focuses on how recent studies have advanced our understanding of these areas. Also discussed are novel insights into the molecular mechanisms contributing to the abnormal RE iron metabolism characteristic of hereditary hemochromatosis and the anemia of chronic disease.

Anemia, Iron-Deficiency↗
PubMed1976

Tumor growth of the reticuloendothelial system.

From the author's hitherto studies on the reticuloendothelial system (RES) it was concluded that the RES is not a single cell system of identical origin, morphology and function but is a group of several types of cells of different origin. From this point of view the heterogeneity of tumors of the RES was studied to reveal the following results. Tumors of the "Reticuloendothel" (Aschoff) reveal pictures of endothelioma, while tumors of histiocytes in connective tissue show findings of fibrohistiocytoma. Histiocytes and reticulum cells of lymph nodes are respectively independent cells, and reticulum cells do not partake in the in the development of histiocytosis or histiocytic sarcoma. Follicular lymphoma is a neoplastic growth of reticulum cells having desmosomes in lymph follicles, and tumor cells of the majority of reticulum cell sarcoma are similar to the cells forming the lymph node anlage in the early fetal stage (lymphoreticular cell). Ewing's sarcoma is considered to be a kind of angiopericytoma.

Animals↗
PubMed1980

Influence of cancer chemotherapy treatment on the reticuloendothelial system in the rat.

The phagocytic function of the reticuloendothelial system (RES) in the rat has been studied after the administration of cyclophosphamide, 5-fluorouracil or a combination of these drugs and vincristine. No impairment in the elimination of 125I-labelled microaggregated human serum albumin was found. A significant reduction in relative and total spleen weight was not paralleled by a decreased splenic uptake of the RES test substance per gram tissue. A significant increase in the relative weight of the lungs was paralleled by a significant increase in the uptake of test substance on a per gram basis. No correr. A general reduction in the cell population of the haematopoietic system has to be assumed. If this reduction is more pronounced in subpopulations of T lymphocytes (suppressor T cells) has to be further tested.

Animals↗
PubMed1981

[Phagocytic activity of the reticuloendothelial system in burn toxicity].

The functional activity of the reticuloendothelial system (RES) was studied in 85 Wistar rats with burn intoxication induced by thermal injury or administration of burn toxoid. It was established that burn injury causes a stable and marked suppression of RES phagocytic activity. This was manifested by a rise in the percentage of Au radioactivity retention in the blood flow and by the decreased phagocytic index. Injections of burnt skin extracts and burn toxoid preparations, i. e. stimulation of burn intoxication depresses the phagocytic activity of hepatic macrophages similarly to the action of natural burn. A decrease in the phagocytic activity of hepatic macrophages under the effect of burn intoxication may serve as a sensitive indicator of the body nonspecific resistance in burn injury, whereas burn toxoid may be regarded as a initiator of changes in the early stage of burn disease.

Animals↗