Bevacizumab Does Not Influence the Efficacy of Partial Splenic Embolization in the Management of Chemotherapy-Induced Hypersplenism.

BACKGROUND: Antiangiogenics attenuate chemotherapy-related hepatotoxicity and portal hypertension. The potential impact of bevacizumab on the efficacy and safety of partial splenic embolization (PSE) in the management of chemotherapy-induced hypersplenism (CIH) has never been investigated. PATIENTS AND METHODS: We conducted a retrospective study with gastrointestinal cancer patients who have undergone PSE for the treatment of thrombocytopenia resulting from hypersplenism. Pre- and post-PSE platelet count (PC), the percentage of patients who resumed systemic therapy, and complication rates were compared between patients exposed and not exposed to bevacizumab. RESULTS: A total of 110 patients were eligible. Colorectal cancer was the predominant neoplasm (60%), and 5-fluorouracil, oxaliplatin, and bevacizumab were the most commonly provided drugs (70%, 65%, and 65% of patients, respectively). After PSE, 80% of patients recovered PC ≥ 100 × 109/L (100K). Systemic therapy was resumed in 81% of patients. Seventy-one patients exposed to bevacizumab had a median PC before PSE of 77.5K and after PSE of 167.0K, with a mean difference of 108K (P < .0001). Thirty-nine patients not exposed to bevacizumab had a median PC of pre-PSE of 73.0K and post-PSE of 187.0K, with a mean difference of 117.7K (P < .0001). Both groups had similar values of percentages of patients with PC post-PSE ≥ 100K (83% vs. 74%; P = .463), resumption of systemic therapy (85% vs. 74%; P = .213), and complication rates. A linear association between splenic infarction rate and increment in PC was found (P < .0001). CONCLUSION: PSE is a safe and effective procedure in the management of CIH, regardless of the provision of bevacizumab. Splenic infarction rate should be optimized to enhance patient outcomes.

Electromagnetic thermoablation to treat thrombocytopenia in cirrhotic and hypersplenic rats.

BACKGROUND AND AIM: Thrombocytopenia due to hypersplenism is usually a serious condition in cirrhotic patients who have undergone invasive procedures. We designed a new treatment method using a high-frequency alternating electromagnetic force to treat the disease condition in a rat model. METHODS: Sprague-Dawley rats were given thioacetamide in drinking water and injected with methylcellulose intraperitoneally to create a cirrhotic hypersplenism model. Spleen volume was determined using the Carlson method. The Control Group consisted of 14 rats, 15 weeks old, that were used to determine the normal platelet count and normal spleen size. Experimental Group I, consisting of 15 rats, received electromagnetic thermoablation of their spleens, after which the spleen was returned to the abdomen. Group II consisted of 13 rats, receiving the same electromagnetic thermoablation as Group I, but the ablated portion was removed. Group III consisted of 14 rats receiving total splenectomies. RESULTS: Cirrhotic hypersplenism was confirmed during laparotomy and pathological examination. Spleen volume enlarged from 1513 +/- 375 mm(3) (Control Group) to 7943 +/- 2822 mm(3) (experimental groups). Platelet counts increased from 0.35 +/- 0.21 x 10(6)/mm(3) to 0.87 +/- 0.24 x 10(6)/mm(3) for Group I, from 0.52 +/- 0.23 x 10(6)/mm(3) to 1.10 +/- 0.20 x 10(6)/mm(3) for Group II, and from 0.47 +/- 0.23 x 10(6)/mm(3) to 1.18 +/- 0.26 x 10(6)/mm(3) for Group III. No rats died due to the treatment in any of the experimental groups. CONCLUSIONS: Our animal model performed successfully and our proposed electromagnetic thermotherapy effectively treated thrombocytopenia due to cirrhotic hypersplenism.

Thrombocytopenia in association with splenomegaly during granulocyte-colony-stimulating factor treatment in mice is not caused by hypersplenism and is resolved spontaneously.

BACKGROUND: Granulocyte-colony-stimulating factor (G-CSF) is used for hematopoietic progenitor cell (HPC) mobilization. Platelet (PLT) counts decrease during G-CSF administration. The mechanisms have not been determined, however. Because splenic pooling of PLTs caused thrombocytopenia in patients with splenomegaly and splenic enlargement was observed in G-CSF-treated donors, it was hypothesized that hypersplenism might cause G-CSF-induced thrombocytopenia. STUDY DESIGN AND METHODS: Mice were treated with several concentrations of G-CSF, and PLT count was measured. Because transfused PLTs should be cleared rapidly from the blood stream under hypersplenic state, PLT life span was studied. To determine direct role of spleen on thrombocytopenia, G-CSF was given to splenectomized mice. Because PLT count did not decrease in G-CSF-expressing transgenic mice, G-CSF was given to mice for a longer period of time and PLT count was investigated. RESULTS: PLT counts decreased while spleen weight increased in a dose-dependent manner by G-CSF treatment. No significant difference in PLT life span was found between G-CSF-treated and control mice. Histologic analysis showed no significant increase in PLT numbers trapped in either spleen or other tissue after PLT transfusion in G-CSF-treated mice. In splenectomized mice as well as in normal mice, G-CSF caused thrombocytopenia. When G-CSF was given to mice for a longer period of time, PLT counts decreased during the first 7 days and thereafter began to increase followed by returning to baseline on Day 15. CONCLUSION: Thrombocytopenia coincided with splenomegaly during G-CSF treatment, but hypersplenism was not responsible for thrombocytopenia. G-CSF-induced thrombocytopenia was a transient event and improved spontaneously despite continual G-CSF treatment.

Effect of IFN-gamma administration in virgin and pregnant mice: distribution of lymphoid and myeloid cells in the spleen.

Administration of Interferon-gamma (IFN gamma) is used in the therapeutic approach for mainly cancer treatment and viral infections in vivo. Recently we observed some important pathologic dysfunctions caused by IFN-gamma administration to pregnant mice. This treatment affected not only the growth and development of the feto-placental unit, but also, among other hematologic disorders, caused splenomegaly to the mother. In an effort to explain the observed hypersplenism, we have analysed the behaviour of macrophages, B and T lymphocytes in the spleen of virgin and pregnant mice after intraperitoneal administration of low IFN-gamma doses. Although the percentage of myeloid Mac-1 and F4/80 positive cells in spleen cell suspensions of virgin and pregnant mice do not change with the IFN-gamma treatment, immunoperoxidase staining of frozen spleen sections shows that in pregnant mice the monocytic cells accumulate at the central white pulp area of the organ, whereas in non-pregnant mice these cells are mainly found at the peripheral red pulp area. In contrast, the same treatment was shown to increase the numbers of Ly5 positive B cells in both virgin and pregnant mice, whereas B cells were found to form clusters only in the case of pregnant animals. We also show that IFN-gamma increases the numbers of Tcyt/sup (Ly2 positive cells) and TH (L3T4 positive cells) in the spleen of virgin mice but not in pregnant mice. Both populations display a physiologic distribution in the white pulp of the organ as assessed by immunoperoxidase staining of frozen spleen sections. Interestingly, the distribution pattern of IL-2- and IL-4-producing cells, which reflects the presence of Th1 and Th2 subpopulations was different in pregnant and virgin mice. Gestating females had IL-2 producing cells dispersed in the white pulp area, whereas IL-4 producing cells formed clusters mainly at the periphery of the organ. Virgin females had almost undetectable levels of IL-4 producing cells, whereas IL-2 producing cells were found at the periphery. Our results indicate that IFN-gamma alters the equilibrium between Th1 and Th2 cells, which in turn is responsible for the redistribution of myeloid and lymphoid cells in the spleen of pregnant mice thereby explaining the development of an active immune/inflammatory reaction.

[Humoral factors of the spleen in the regulation of the calcium content in blood plasma of rats]. / Gumoral'nye faktory selezenki v reguliatsii soderzhaniia kal'tsiia v plazme krovi u krys.

Introduction of protein-free peptides-enriched spleen extract increases the calcium content in blood plasma of rats. After the effect of stress factor (long swimming) it falls. The value of the index under study increases in the splenectomized rats and remains unchanged after stress and introduction of the spleen factors. The most pronounced increase of the calcium concentration is observed in the case of experimental hypersplenism induced by methylcellulose introduction. The calcium-regulating effects of introduction of the enriched protein-free spleen extract and pharmacopoeial splenin preparation are compared. It is supposed that spleen contains two humoral factors of different chemical nature which are able to influence somewhat differently the calcium content in blood plasma.

[Chronic fatal vitamin A poisoning with hemolytic anemia]. / Chronische, letal verlaufende Vitamin-A-Vergiftung mit hämolytischer Anämie.

A case of chronic, lethal vitamin A intoxication is reported, the diagnosis of which was not established intra vitam. The patient presented with chronic mixed prehepatic and hepatic icterus and hypersplenism with hemolytic anemia. On post mortem histological examination, abundant deposits of neutral lipids in the reticuloendothelial cells of liver, spleen and bone marrow were found. Chemical analysis of the lipids extracted from these organs revealed esterified fatty acids. Triglycerides could be ruled out since the triglyceride content of the patient's liver was significantly lower than that of a normal control. By means of thinlayer chromatographic analysis it was possible to identify retinol, i.e. retinylester (vitamin A) in the deposits. Vitamin A was determined photometrically and found to be very elevated in the liver and, to a lesser degree, in the spleen of the patient. These findings lead to a definite diagnosis of chronic hypervitaminosis A. Unique features of the case presented are both hemolytic anemia and the lethal outcome of the chronic hypervitaminosis A.

A study of experimental hypersplenism.

Methyl cellulose syndrome induced by repeated i. p. injections of methyl cellulose (MC) was followed in experimental rats. Following application of 2--4 MC injections early haematological changes are observed including increased values of reticulocytes, development of serum aggregation factor having anti-erythrocyte antibody nature and altered filtrability of non-washed erythrocytes. Later alterations developing with further MC injections (8-32) are characterized by expressive splenic enlargement, by decrease in erythrocyte and platelet values and by additional increase in number of reticulocytes. The cause of anaemia is pooling and sequestration of erythrocytes in the spleen and haemodilution from hypervolaemia blood plasma. The decreased platelet amount is the result of reduced survival time of platelets due to their increased sequestration in the spleen. Haematological changes are normalized after splenectomy. This picture resembles to a great extent human hypersplenism.

Increased susceptibility to pneumococci after ligation of the splenic artery in experimental hypersplenism.

22 male Sprague-Dawley rats were divided into two groups, of which group I received methylcellulose and group II saline intraperitoneally for 12 weeks. After ligation of the splenic artery of the animals in group I and sham operation of the rats in group II, the injections were continued for a further 9 weeks. At the operation, the group I animals all showed signs of hypersplenism with anemia, and leuko- and thrombocytopenia. The platelet counts normalized after the operation, a marked leukocytosis developed and the anemia was further aggravated. At the end of the study, the animals were challenged with 4 x 10(6) colony-forming units of pneumococci type 1, resulting in deaths of 11 of 12 animals in group I, in contrast to survival of all 10 rats in group II (p = 0.000017).

Treatment of hypersplenism An experimental study in the rat.

Methylcellulose injected intraperitoneally into rats proved to give a splenomegaly combined with anemia and thrombocytopenia. The white blood cell count did not change during the treatment. The splenic parenchyma of the hypersplenic rats was then reduced by resection or splenic artery ligation to a different extent. The peripheral blood cell count was normalized after a one-third resection, whereas a more-than-two-thirds reduction of the splenic parenchyma caused infective complications in many rats. It was thus possible to treat the 'secondary hypersplenism' in the rat by a partial reduction of the splenic parenchyma and to avoid total splenectomy, much undesired with new immunologic knowledge.

The sequestration capacity of "hypersplenic" rat spleens for heat-damaged erythrocytes.

The sequestration capacity of the spleens of controls and hypersplenic rats was examined. Hypersplenism was induced by long-term intraperitoneal application of methyl cellulose. The animals were injected single doses of various amounts of heat-damaged 51Cr-labelled erythrocytes (0.1 ml to 1.5 ml); radioactivity in spleen was determined 4 hrs. following application. The amount of red cells sequestrated in the spleens of hypersplenic animals was significantly increased against the controls, after administration of massive volumes of cells. The maximum amount of erythrocytes sequestrated in the spleens of the control rats amounted to an average weight of spleens 1.25 g to 0.158 ml (0.126 ml per g of spleen), and in hypersplenic animals to an average weight of the spleen of 4.87 g to 0.283 ml (0.058 ml/l g of spleen weight).

Splenic artery ligation in experimental hypersplenism.

The effects of splenic artery ligation (SAL) were examined in Sprague-Dawley rats with methyl-cellulose-induced hypersplenism. When performed close to the splenic hilium, SAL effectively reduced functioning splenic mass and raised peripheral counts of leukocytes and platelets, a response similar to that following total splenectomy. In hypersplenism, therefore, a satisfactory hematologic response may not necessary require total ablation of the spleen but merely substantial reduction of functioning splenic tissue.

Filtrability of erythrocytes in "hypersplenic" rats.

The values of haemoglobin, reticulocytes and half-times of the filtrability of non-washed and washed erythrocytes were examined in male albino rats, Wistar strain, after i.p. injections of methylcellulose (MC) and compared with controls. In individual experiments the rats received 2 to 32 injections of MC. In injected animals, the filtrability of non-washed erythrocytes was altered. The filtrability half-times of the washed erythrocytes did not differ from the controls. Thus, the filtrability is altered for extracorpuscular reasons. "Hypersplenism" being completely developed, (after 32 MC injections), the filtrability of non-washed erythrocytes repaired when the application of MC had been discontinued, the reticulocyte values remained however increased. Problems of the mechanism of anaemia in experimental "hypersplenism" after MC injections in rats and relations between the altered filtrability of the erythrocytes and the haemolysis are discussed.

Histological findings of hypersplenism after experimental intraperitoneal injection of methyl cellulose and ligature of the splenic artery in rats.

The intraperitoneal injection of methyl cellulose in rats causes splenomegaly and hypersplenism. Clusters of foam cells in form of granulomas develop. They are containing methyl cellulose. The ligature of the splenic artery damages mainly the white pulp. Even after ligature of the splenic artery absorption of methyl cellulose continues. The reticular cells released by the reticulum remain capable of phagocytic action. After previous injection of methyl cellulose the ligature of the splenic artery causes normalization of the peripheral blood values.

Erythropoietin formation in rats with experimental hypersplenism.

Splenomegaly accompanied by anaemia, increased reticulocyte and decreased thrombocyte counts, was induced in Wistar rats by a long-term intraperitoneal administration of methylcellulose. Compared to controls, hypersplenic rats showed significantly enhanced utilization of 59-Fe by red cells and increased titre of erythropoietin. After the exposure of rats to hypoxic hypoxia corresponding to an altitude of 7,000 m for 6 h, no difference in the erythropoietin titre was found in either group. The results suggest that experimental hypersplenism alone does not affect the production of erythropoietin and does not stimulate the formation of an inhibitor of erythropoietin or erythropoiesis. The increased titre of erythropoietin and enhanced utilization of radioiron by red cells in rats with hypersplenism were found to be due to haemolytic anaemia leading to the stimulation of erythropoiesis.