Response to immunization after partial and total splenectomy

Survival after infection from Streptococcus pneumoniae in both animals and man is influenced by the amount of splenic tissue. We investigated the effect of differences in splenic weight upon the antibody response to immunization and the effect of immunization upon survival after pneumococcal challenge. Young Sprague-Dawley rats had either sham operation, hemisplenectomy, splenectomy with splenic autotransplantation, or total splenectomy. Nine weeks later, rats were immunized with a heat- and formalin-killed type-specific pneumococcal vaccine. Antibody response measured by radioimmunoassay was similar in all operative groups and was significantly higher than in nonimmune rats (P less than 0.01). Splenic weight was less after hemisplenectomy or autotransplantation than in sham-operated animals (P less than 0.01). Immunization improved survival after live pneumococcal challenge in rats that had autotransplantation and total splenectomy (P less than 0.001). Our results demonstrate that splenic weight does not affect the antibody response to pneumococcal immunization in rats. Immunization improves survival after bacterial challenge in susceptible animals and minimizes the detrimental effect of reduction in splenic mass.     

Regeneration of splenic remnants after partial splenectomy in rats

Splenic regeneration in the rat was measured after removal of 25, 50, or 75% of the spleen, 50% of the spleen with autotransplantation of the excised portion, and splenectomy with autotransplantation of 50% of the spleen. Splenic growth in rats undergoing sham splenectomies served as a control. Splenic mass at 6 weeks and 4 months after surgery was directly related to the remnant size. “Normalized” spleen weights (measured as grams of splenic tissue per 100 grams of rat weight) after 25, 50, and 75% splenectomy were 57, 41, and 38% of controls at 6 weeks, and 77, 71, and 44% of controls at 4 months. All differences were significant at P < 0.03 except those between 50 and 75% splenectomy at 6 weeks, and between 25 and 50% splenectomy at 4 months. A comparison of autotransplanted splenic mass after total splenectomy with that after 50% splenectomy (0.042 ± 0.005 and 0.025 ± 0.004, respectively, at 6 weeks) demonstrated that an intact subtotal spleen inhibited significantly regeneration of the autotransplanted spleen. The effect of autotransplanted splenic tissue on regeneration of a splenic remnant was little to none at 4 months.     

Splenic tissue autotransplantation in rabbits: no restoration of host defense

BACKGROUND: The loss of spleen may increase the incidence of overwhelming sepsis. To prevent this, splenic autotransplantation has been performed in humans and experimental animals. However, there is still controversy about the effectiveness of regenerated splenic tissue in preventing infection. This study explored the effectiveness of splenic tissue autotransplantation in restoring host defense. MATERIALS AND METHODS: Rabbits were divided into three groups: splenic autotransplantation, sham operation, and total splenectomy. Histomorphology, T-lymphocyte count, serum lysozyme levels, hemolysin titers, and pneumococcal clearance were observed as read-out parameters over 24 weeks. RESULTS: Histological study showed that the white pulp was poorly developed and central arterioles were missing in the regenerated splenic tissue of the autotransplanted rabbits. The weight of regenerated spleens recovered 6 months later in the splenic autotransplantation group was 11% of that in the sham operation group and was significantly less than the weight at implantation. There was no significant difference in the number of T lymphocytes or level of serum lysozyme between the three groups. A poor antibody response by the rabbits in the splenic autotransplantation and total splenectomy groups was noted after the primary intravenous administration of sheep red blood cells compared to those of sham operation group. After the challenge with type 3 pneumococci intravenously, pneumococcal clearance from the bloodstream in the splenic autotransplantation group did not differ significantly from that in the total splenectomy group, but was markedly delayed compared with that in the sham operation group. CONCLUSIONS: The low quantity and poor quality of the regenerated splenic tissue contribute to the inferior immunoprotective ability of animals autotransplanted with one-third of the original spleen. This suggests that the regenerated spleen cannot compensate for the immunological function of the original one, especially host resistance to infection.     

Immune cell subpopulations in regenerated splenic tissue in rats.

BACKGROUND: Asplenic patients have an increased risk of infections. Operations such as autotransplantation or splenic artery ligation have been suggested to ensure retention of functional splenic tissue after splenectomy, but their protective value is unclear. Immune responses, such as production of antibody, remain impaired in humans and animals even when such tissue is present, and phagocytosis is less efficient than by normal spleen tissue. In the present study the cellular composition of regenerated tissue is determined. METHODS: Splenic tissue was obtained from rats 6-9 months after splenic autotransplantation, splenic artery ligation or sham operation. The lymphocyte and macrophage subpopulations were labelled using a panel of monoclonal antibodies and analysed by flow cytometry. RESULTS: Both the total number of cells and the number of cells per gram of tissue were significantly reduced. There was a substantial reduction in the percentage of some of the cells examined (CD4+ and CD8+ T lymphocytes subsets), but not all (B lymphocytes, ED1+ and ED2+ macrophages, OX2+ and OX6+ cells). CONCLUSIONS: The reduction in the T lymphocyte subsets in regenerated splenic tissue compared with the normal spleen might explain the immunological dysfunction which persists after splenic autotransplantation. The reduction in the number of macrophages may be responsible for the alteration in phagocytic efficiency of regenerated splenic tissue.     

Decreased phagocytic capacity of autotransplanted splenic tissue

Background: Asplenic patients have an increased risk of infections. Operations such as autotransplantation have been proposed to restore functional splenic tissue after splenectomy, but the protective value of this tissue is unclear. Immune responses such as production of antibody remain impaired in humans and animals even when such tissue is present, and clearance of particles from the blood is reported to be less efficient than by normal spleen tissue. The present study investigated the phagocytic capacity of cells in the regenerated tissue in vitro, free of the confounding effects of hepatic clearance. Methods: Single cell suspensions were prepared from splenic tissue from rats 6 months after splenic autotransplantation or sham operation. Phagocytosis of killed, fluorescein‐labelled bacteria was measured by flow cytometry. Results: Autotransplanted tissue contained fewer phagocytic cells than normal tissue, and these cells phagocytosed less per cell. Phagocytosis by spleen cells was dependent on heat‐labile opsonic factors. Conclusions: Autotransplanted splenic tissue does not restore the phagocytic capacity lost following splenectomy.     

Distribution of peripheral blood cells in mice after splenectomy or autotransplantation

Our aim was to compare the distribution changes of peripheral leukocytes and erythrocytes in splenectomized and spleen-autotransplanted BALB/c female mice (n = 96), 2 and 8 months after surgery. In total, there were eight groups of animals: splenectomy, autotransplantation, sham, and untreated controls at both time points. We used the spleen-apron method of Furka et al. (Khirurgiia (Mosk) 1989;9:125-127), inserting five spleen chips into the greater omentum, for autotransplantation. Quantitative and qualitative blood cell counts and the phagocytic activity of cells (stimulated with zymosan) were determined. In splenectomized animals, the number of neutrophils significantly increased 8 months after surgery. The greatest phagocytic activity of neutrophils, however, was observed in autotransplanted animals of the same age. In splenectomized animals, erythrocyte volumes were significantly higher in the second postoperative month, but normalized by the eighth month. In conclusion, spleen autotransplantation has some beneficial effects, including clearing erythrocytes and preserving the phagocytic activity of neutrophils in peripheral blood.     

Phagocyte function after splenic autotransplantation

This study was designed to examine the role of splenectomy and autotransplantation with regard to the leukocyte/differential cell counts and the function of peripheral blood phagocytes. Eleven groups of 40 Wistar male rats in each group either underwent total splenectomies or sham operations. The splenectomized groups underwent autotransplantations with 10% through 90% of the weight of the intact spleen. The leukocyte count and the oxidative burst response of the blood leukocytes were measured in each group. It was shown that a total splenectomy did not alter the leukocyte/differential cell counts. Furthermore, the blood picture remained basically unchanged after an autotransplantation with 10% through 90% of the weight of the intact spleen. The phagocyte oxidative burst response was measured by chemiluminescence. The chemiluminescence response of these cells was reduced after a total splenectomy. The phagocyte oxidative burst response returned to normal levels following an autotransplantation. There was no correlation between the amount of autotransplanted spleen and the degree of the oxidative burst response. These findings indicated that a splenectomy results in a diminished phagocyte oxidative burst response and that a spleen autotransplantation returns this function to normal levels.     

Relative merits of partial splenectomy, splenic reimplantation, and immunization in preventing postsplenectomy infection.

Partial splenectomy, splenic autotransplantation, and immunization with pneumococcal vaccine have been reported to protect patients against overwhelming postsplenectomy infection, and this study was undertaken to evaluate these therapeutic alternatives. For this purpose 136 rats were divided into experimental groups: 34 controls, 34 splenectomy, 34 partial splenectomy, and 34 splenic autotransplantation animals. Five weeks after operation, two-thirds of the animals were immunized with killed pneumococci. The effects of operation and immunization were studied by challenging the animals intravenously with pneumococci. Pneumococcal antibody titers were determined, and phagocytic uptake of pneumococci by the spleen and liver was measured. Immunization impressively increased the survival rate in all groups. At low-challenge doses autotransplantation prolonged survival. At higher-challenge doses only partial splenectomy increased survival. Partial splenectomy and control animals had higher antibody titers than did splenectomy and autotransplantation rats. Animals with the highest antibody titers had the greatest splenic and hepatic phagocytic uptake of pneumococci. Partial splenectomy was more efficient in removing pneumococci than was autotransplantation. Thus immunization is one of the most important factors contributing to survival after splenectomy. Partial splenectomy is preferable to splenic autotransplantation because it is associated with higher antibody titers after immunization, better pneumococcal splenic uptake, and improved survival rates.     

Experimental study on function of regenerated splenic tissue after splenic autotransplantation

To prevent postsplenectomy overwhelming sepsis, splenic autotransplantation has been clinically attempted. However, function of regenerated splenic tissue after splenic autotransplantation has not been completely understood. Changes in weigh of regenerated splenic tissue, splenic blood flow, splenic immune responses and phagocytic function were studied for one year after splenic autotransplantation using Sprague-Dawley rats. At one year after autotransplantation, the weight of regenerated splenic tissue was increased to 80% of the originally implanted spleen and the blood flow was increased to 80% of the control spleen. The counts of lymphocytes and macrophages in the regenerated splenic tissue were significantly low at eight weeks after transplantation, however lymphocytes was increased to 58.8% and macrophages was increased to 29.5% of the control spleen at 16 weeks after transplantation. The blast formation of splenic lymphocytes was lower at the early stage after transplantation, thereafter, it was increased at the later time after transplantation. Microangiography of the regenerated spleen showed new capillaries around the implanted tissue 2 weeks after transplantation. These results suggested that the transplanted splenic tissue was regenerated to the similar structure to normal spleen and immunological function was recovered close to the normal splenic tissue.     

Pulmonary antipneumococcal defenses after hemisplenectomy

Conservative splenic surgery such as partial splenectomy is advocated for splenic injuries, since splenectomy predisposes individuals to overwhelming sepsis with encapsulated organisms, of which Streptococcus pneumoniae is the most frequently isolated. The respiratory route is argued to be the most likely portal of entry of pneumococci; however, little data exist on the interaction of the spleen and pulmonary defense mechanisms against pneumococcal invasion. We studied the effect of splenectomy, 50% splenectomy (hemisplenectomy), 25% splenectomy, and sham operation on in vivo clearance of live pneumococci from the lungs of male CD-1 mice following an aerosol challenge of pneumococci. Splenectomy impaired pneumococcal clearance from mouse lung pairs and allowed for increased translocation of live pneumococci to tracheobronchial lymph nodes compared to sham-operated controls. Preservation of splenic mass by partial splenectomy improved lung clearance and allowed for fewer bacteria to be cultured from tracheobronchial lymph nodes compared to splenectomized animals. Clearance of live pneumococci from the lungs and survival were directly proportional to the amount of splenic tissue remaining. Splenic factors probably exist which regulate reticuloendothelial cell function throughout the host. Maintaining adequate splenic mass, therefore, is an important consideration when operating for splenic trauma.     

自体脾腹膜后移植在创伤性脾破裂中的临床应用

目的探讨自体脾组织移植在治疗创伤性脾破裂的应用.方法对本组于2000年1月至2005年4月22例脾破裂行全脾切除后,再行自体脾组织腹膜后移植术.通过检测外周血IgM、IgA、IgG水平和B超,CT、99mTc扫描来观察移植脾片成活和吞噬功能恢复情况.结果术后随访均显示移植脾存活良好,脾功能满意.结论自体脾组织移植可作为严重脾外伤全脾切除术后保留脾功能的一个重要有效手段.     

IMMUNE CELL SUBPOPULATIONS IN REGENERATED SPLENIC TISSUE IN RATS

Background : Asplenic patients have an increased risk of infections. Operations such as autotransplantation or splenic artery ligation have been suggested to ensure retention of functional splenic tissue after splenectomy, but their protective value is unclear. Immune responses, such as production of antibody, remain impaired in humans and animals even when such tissue is present, and phagocytosis is less efficient than by normal spleen tissue. In the present study the cellular composition of regenerated tissue is determined. Methods : Splenic tissue was obtained from rats 6–9 months after splenic autotransplantation, splenic artery ligation or sham operation. The lymphocyte and macrophage subpopulations were labelled using a panel of monoclonal antibodies and analysed by flow cytometry. Results : Both the total number of cells and the number of cells per gram of tissue were significantly reduced. There was a substantial reduction in the percentage of some of the cells examined (CD4⁺ and CD8⁺ T lymphocytes subsets), but not all (B lymphocytes, ED1⁺ and ED2⁺ macrophages, OX2⁺ and OX6⁺ cells). Conclusions : The reduction in the T lymphocyte subsets in regenerated splenic tissue compared with the normal spleen might explain the immunological dysfunction which persists after splenic autotransplantation. The reduction in the number of macrophages may be responsible for the alteration in phagocytic efficiency of regenerated splenic tissue.     

Splenic autotransplantation for treatment of portal hypertension.

BACKGROUND: When total splenectomy is unavoidable it is important to preserve splenic function in some form in order to prevent the complications of asplenism. Splenic autotransplantation is a good alternative in such cases. We describe the use of splenic autotransplantation for the treatment of portal hypertension. METHODS: We carried out total splenectomy on 31 patients (21 men, 10 women), ranging in age from 21 to 68 years, with schistosomal portal hypertension. From each removed spleen, we took 20 fragments and implanted them on the greater omentum. This procedure was combined with abdominal portal-variceal disconnection. Transgastric running suture of the lower esophageal and gastric varices completed the treatment of portal hypertension. All patients underwent clinical, hematologic, immunologic and scintigraphic assessment. The results with respect to morbidity and mortality, and hematologic and immunologic findings were compared with those in 36 patients submitted to other splenic procedures. RESULTS: There was no complication related to the splenic implants and none of the patients died. Hematologic and immunologic findings were normal. Scintigraphy registered images of splenic tissue in all cases. CONCLUSION: The implantation of splenic fragments on the greater omentum seems to be a safe and useful procedure for maintaining splenic function after total splenectomy.     

Laparoscopic subtotal splenectomy

BACKGROUND: Since 1979, we have been studying subtotal splenectomy. This procedure was used in over 200 patients to treat splenic trauma, portal hypertension, myeloid metaplasia due to myelofibrosis, Gaucher disease, chronic lymphocytic leukemia, retarded growth, and sexual development associated with splenomegaly, and disorders of the pancreatic tail. On the basis of our clinic experience with laparoscopic splenectomy with and without splenic autotransplantation, open subtotal splenectomy, and after a training period with laparoscopic conservative splenic operations on animals, this communication presents laparoscopic subtotal splenectomy as a new treatment of severe pain due to ischemia of the spleen. PATIENTS AND METHODS: Two patients with severe splenic pain due to ischemia provoked by vascular obstruction of the spleen were successfully treated by laparoscopic subtotal splenectomy, with preservation of the upper splenic pole supplied only by the gastrosplenic vessels. RESULTS: This procedure was safely conducted with minor bleeding and no technical difficulties or complications. The postoperative follow-up of 5 and 21 months has been uneventful and the pain disappeared since the first postoperative day. CONCLUSIONS: It is feasible and safe to perform subtotal splenectomy by laparoscopy. This procedure seems to be a good treatment for pain due to splenic ischemia.     

Optimal site and amount of splenic tissue for autotransplantation.

Clinical and basic studies have documented a high susceptibility to pneumococcal infection in asplenic humans and animals. It has been suggested that autotransplantation of splenic tissue might be a method of providing host resistance when total splenectomy is necessary. However, the effect of splenic autograft has remained controversial. This study was performed to evaluate the most effective site and amount of splenic autograft using rats. Rats were divided into five groups for the purpose of determining the site of splenic autotransplantation: splenectomy, sham operation, implantation into the omental pouch, intraperitoneal implantation, and intramuscular implantation. For determining the amount for autotransplantation, the rats were divided into seven groups: splenectomy, sham operation, and implantations of 25, 50, 100, 200, or 300 mg of splenic tissue. All animals were challenged with Streptococcus pneumoniae type 6, 16 weeks after surgery. Howell-Jolly bodies appeared postsplenectomy, but disappeared in the implanted rats 16 weeks after the operation. Histologically, the implanted tissue was indistinguishable from that of a normal spleen. Pneumococcal clearance from the bloodstream and survival rate were significantly higher in rats implanted in the omental pouch as compared with splenectomized rats. Intraperitoneal and intramuscular implanted rats did not show a significant difference from the splenectomized rats. More than 50% of splenic tissue for autograft showed a significant increase in pneumococcal clearance and survival rate as compared with that of splenectomized rats. It was suggested that the most effective site of autotransplantation is the omental pouch and approximately 50% of the whole spleen would be necessary for prevention from sepsis.     

Posttraumatic autotransplantation of spleen tissue

Clinical and laboratory studies have documented high susceptibility to pneumococcal infection in asplenic humans and animals. Splenic autotransplantation has been suggested as a method of preserving function. Autotransplantation of irreparably damaged spleens in humans preserved splenic functions. Ten patients operated on for blunt abdominal trauma required unavoidable splenectomy. In each, autotransplantation of the removed spleen (roughly 50 g) was performed. Postoperative studies of splenic functions revealed disappearance of Howell-Jolly bodies from peripheral blood. Levels of IgM, which were initially significantly depressed, returned to normal and there were normal technetium Tc 99m sulfur colloid scans ten weeks after surgery. All patients are alive and healthy. Our data suggest that autotransplantation of spleen is a safe alternative method for preserving splenic function when total splenectomy is mandatory for hemostasis.     

The Effects of Splenectomy and Splenic Autotransplantation on Plasma Lipid Levels

Purpose: Atherosclerosis observations after splenectomy for trauma and hypersplenism suggests a possible role for the spleen in lipid metabolism. The authors examined the effects of splenectomy on serum lipids in rats and also cholesterol-fed rats with experimental atherosclerosis. Methods: This study was designed on rats. The rats were divided into five groups: splenectomy, normal diet (SP-N, n: 8), splenectomy, cholesterol-fed groups (SP-C, n: 8), splenic autotransplantation after splenectomy, normal diet (SA-N, n: 8), splenic autotransplantation after splenectomy, cholesterol-fed groups (SA-C, n: 8) and sham groups (n: 8). Total triglyceride, total cholesterol, HDL (high-density lipoprotein), LDL (low-density lipoprotein), and VLDL (very low-density lipoprotein) levels were determined in 40 rats. The rats were classified into five groups based on the surgical procedures. The spleens were removed and then the rats were fed a normal diet in Group SP-N (n = 8). The spleens were removed and then the rats were fed a diet containing 1% cholesterol in Group SP-C (n = 8). Splenectomy and splenic autotransplantations were performed and then the rats were fed a normal diet in Group SA-N (n = 8). Splenectomy and splenic autotransplantations were performed and then the rats were fed a diet containing 1% cholesterol in Group SA-C (n = 8). The rats were sham-operated in the control group (Group S, n = 8). An active splenic function was shown in rats that underwent splenic autotransplantation in both groups by using Technicium 99 m sulphurcolloide sintiscan on day 30. Blood lipid levels were repeated 6 months later. Results: There was no difference between pre- and postoperative lipid levels in the sham group and SA-N group (p >.05). All lipid levels including HDL were increased significantly in SP-C group (p <.05). Also VLDL and total tryglyceride levels were increased significantly in SP-N and SA-C groups (p <.05). Conclusions: This study showed that the spleen might have an important effect on lipid metabolism and splenic autotransplantation may be protective in conditions with increased lipid levels.     

The immunological studies on the splenectomy and the splenic autotransplantation in BALB/C mice

Recently, it has been demonstrated that the severe infectious diseases are often caused after splenectomy. The significance of spleen on humoral immunity has been pointed out, however the alterations of cellular immunity by splenectomy has not yet been investigated sufficiently. In this study, the effects of splenectomy on the immunological aspects were examined. And the reconstruction of immunological responses by the splenic autotransplantation was also examined. The results obtained were as follows. The antibody titers against SRBC of the splenectomized groups continued to be apparently lower than those of sham-operated groups. The IgM of the splenectomized groups showed lower values than that of the sham-operated groups, but concerning IgG, no distinct differences were noticed among these two groups. On the proliferation of peripheral lymphoid cells, the splenectomized groups from 4th week later showed a higher response than the sham operated groups. The splenic autotransplanted groups showed a similar response to the sham operated ones in the antibody production against SRBC, and the proliferations of lymphocytes. The splenic autotransplantation might be suggested to be a worthy application.     

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目的探讨医源性脾损伤的发生原因和防治措施。方法回顾性分析1992～2002年上海第二医科大学附属宝钢医院26例与手术操作相关的脾损伤病例。结果全组病例均经手术证实，医源性脾损伤发生于结肠手术中占31％(8／26)、胃手术中占27％(7／26)、胰腺手术中占15％(4／26)，其他手术中占27％(7／26)。本组均经手术治愈，其中行单纯脾切除6例，脾切除加自体脾移植2例，脾修补5例，13例应用了局部止血措施。结论良好的麻醉和细致的手术操作可以有效预防医源性脾损伤的发生，而根据伤情合理选择术式是治疗医源性脾损伤的关键。     

Comparison of omental splenic autotransplant to partial splenectomy. Protective effect against septic death

The possible benefit of either partial splenectomy or splenic autotransplantation as protection against post-splenectomy sepsis was investigated. Sprague-Dawley rats were challenged with intravenous Streptococcus pneumoniae and the incidence of bacteremia and mortality were recorded. Animals were divided into four groups based upon the amount of splenic tissue conserved: total splenectomy (0%), partial splenectomy (62%), splenic autotransplantation (27%), or sham celiotomy (100%). A statistically significant (P 0.05) decrease in the incidence of septic death was seen in comparing the total splenectomized animals (63%) to the autotransplant group (27%), the partial splenectomy (4%) and the control group (4%). This diminishing mortality is inversely proportional to the amount of splenic remnant in the respective groups. There was a similar, parallel relationship in the incidence of Streptococcus pneumoniae bacteremia. Thus, the greater the amount of remaining splenic tissue, the lower the incidence of bacteremia and subsequent mortality, implying the preservation of immunologic function with splenic conservation.