Splenic autotransplantation: determination of the optimum amount required for maximum survival

Splenic salvage in cases of traumatic or iatrogenic injuries may require autotransplantation of splenic fragments when splenorrhaphy or partial splenectomy is not possible. There are no studies which address the issue concerning the optimal amount of spleen to be transplanted in order to yield maximal survival in a model of pneumococcal sepsis. This study uses a Sprague-Dawley rat model to attempt to clarify this issue. Animals were divided into seven groups: control, total splenectomy, 25, 40, 60, 80, and 100% omental pouch autotransplantation. These animals were challenged with intravenous Streptococcus pneumonia Type I after 24 weeks, and mortality and blood culture results were monitored. Transplants were recovered and weights were compared with the weights originally transplanted. Survival and blood culture results were seen to improve in a linear quantitative fashion as the amount of spleen autotransplanted increased up to 80%, after which no further improvement was seen. This data supports the autotransplantation of 80% of the spleen in the Sprague-Dawley rat as the optimum amount to achieve maximal survival in a model of pneumococcal sepsis.     

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 response capacity after human splenic autotransplantation: restoration of response to individual pneumococcal vaccine subtypes

OBJECTIVE: To evaluate features of general immune function, in particular the restoration of the humoral immune response to pneumococcal capsular polysaccharides, in humans undergoing a spleen autotransplantation after splenectomy because of trauma. SUMMARY BACKGROUND DATA: After splenectomy, patients have an increased risk of overwhelming infection or sepsis involving encapsulated bacteria such as pneumococci. The value of human spleen autotransplantation after splenectomy because of trauma has long been questioned. Mononuclear phagocyte system function appeared to be similar to that in splenectomized persons. The presence of specific antipneumococcal antibodies would allow other parts of the mononuclear phagocyte system, such as those in the liver, to phagocytose opsonized bacteria. METHODS: Ten consecutive patients undergoing splenectomy followed by autotransplantation were compared with the next 14 consecutive patients undergoing splenectomy alone. After a minimum of 6 months, the patients were vaccinated with 23-valent pneumococcal vaccine. Blood samples were taken at the time of vaccination and after 3 and 6 weeks for antipneumococcal capsular polysaccharides IgM and IgG enzyme-linked immunosorbent assay against types 3, 4, 6, 9, 14, and 23. Splenic regrowth was evaluated by scintigraphy. RESULTS: Surprisingly, several of the nonautotransplanted patients showed scintigraphic activity, indicating the presence of either accessory spleens or traumatic seeding (splenosis). Significant antibody titer increases (more than twofold) were found for both IgM and IgG in the autotransplanted patients. Splenectomized-only patients showed no significant increase in Ig levels in patients without splenic regrowth and partial improvement in patients with splenosis/accessory spleens. CONCLUSIONS: Considering this significant antipneumococcal antibody increase, spleen autotransplants can be expected to permit an adequate humoral response to pneumococcal infections and presumably also to other TI-2 antigens, and to protect against overwhelming postsplenectomy infection or sepsis.     

Splenic phagocytic function after partial splenectomy and splenic autotransplantation

We investigated splenic reticuloendothelial activity after splenic preservation procedures to determine their effect upon the phagocytic function of the spleen. We performed the following procedures in Sprague-Dawley rats: sham laparotomy, total splenectomy, hemisplenectomy, subtotal splenectomy, or total splenectomy with intraperitoneal splenic autotransplantation. At nine weeks after operation, phagocytic function of the spleen was determined by measuring radiocolloid uptake. Mean (+/- SEM) splenic phagocytic indices for sham laparotomy (41.2 +/- 2.9), hemisplenectomy (44 +/- 2.9), and subtotal splenectomy (43.2 +/- 5.2) were similar; however, the phagocytic index was reduced markedly after autotransplantation (15.8 +/- 2.2). These data demonstrate that the phagocytic function of the spleen after hemisplenectomy and subtotal splenectomy correlates highly with the weight of the splenic remnant; however, phagocytic function after autotransplantation remains reduced even after accounting for differences in splenic weight.     

Partial splenectomy and overwhelming infection in rats

Susceptibility to overwhelming sepsis in rats was measured by intravenous Streptococcus pneumoniae challenge 5 weeks after removal of 25, 50, or 75% of the spleen, with sham splenectomy and total splenectomy groups included for comparison. The LD₅₀ (given in organisms per animal) for total splenectomy was 1.02 × 10³, for 75% splenectomy, 1.79 × 10⁴, for 50% splenectomy, 4.69 × 10⁴, for 25% splenectomy, 4.90 × 10⁵, and for sham splenectomy, 8.04 × 10⁶. All differences were significant at P < 0.05 except for that between 50 and 75% splenectomy. Thus sham, 25, 50, and 75% splenectomy were all associated with a higher LD₅₀ than total splenectomy, and the LD₅₀ increased in proportion to the size of the splenic remnant. No threshold for protection against overwhelming infection was noted, but a rapid fall in LD₅₀ from 75% to total splenectomy may be indicative of a critical splenic mass within that range.     

自体脾移植联合食管横断吻合术治疗肝硬化门静脉高压症

目的 探讨腹膜后自体脾移植联合食管横断吻合术治疗肝硬化门静脉高压症的临床疗效.方法 将2003年1月至2006年12月收治的36例肝硬化门静脉高压症患者随机分为自体脾移植组(n=18)和脾切除组(n=18),自体脾移植组接受脾切除、食管横断吻合及自体脾移植术,脾切除组接受脾切除、食管横断吻合术.于术前及术后2～6个月定期观察两组患者的一般情况、行脾脏放射性核素扫描,同时检测肝功能、血清促吞噬素(Tuftsin)及IgM水平,并行组间及手术前后比较分析.结果 自体脾移植组患者术后2个月血清Tuftsin和IgM水平与术前比较无明显差异(P0.05),而脾切除组患者术后2个月血清Tuftsin和IgM水平较术前明显降低(P<0.05);自体脾移植术对患者肝功能无明显影响;术后2个月放射性核素扫描证实移植脾于腹膜后存活.结论 自体脾移植对保留机体脾脏免疫功能具有重要价值,腹膜后自体脾移植联合食管横断吻合术治疗肝硬化门静脉高压症的临床效果确切,值得推广应用.     

Does survival depend on the amount of autotransplanted splenic tissue?

Susceptibility to Streptococcus pneumoniae infection was studied in 11 groups of rats allocated to sham operation, splenectomy, or splenic autotransplantation of 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, or 90% of the removed spleen. Three months later, all rats were exposed intravenously to type 1 Streptococcus pneumoniae (median lethal dose, LD50, for control group). Survivors were killed 13 days after the bacterial challenge. Autopsy showed that more splenic tissue was recovered in rats that received less than 50% splenic tissue compared with those that received 50% or more. More survivors were found among sham-operated rats (47.5%; 95% confidence intervals, 32 to 68) and rats that had 40% splenic tissue implanted (35%; confidence interval, 20 to 54) or those that were found to have regenerated 40% splenic tissue. We conclude that 40% of the spleen should be autotransplanted to protect the rat optimally against infection after splenectomy.     

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.     

Serum antibody responses to pneumococcal vaccine after splenic autotransplantation

Immunization with pneumococcal capsular polysaccharide vaccines is advocated after splenectomy; however, experimental and clinical data suggest an impaired antibody response in splenectomized individuals. This study examined the value of splenic autotransplantation at various sites in augmenting the antibody response to Type III pneumococcal capsular polysaccharide in mice immunized 3 months after operation. Splenectomy resulted in impaired antibody responses compared to sham-operated mice (p less than 0.001) using an enzyme-linked immunosorbent assay. Mice with intraperitoneal splenic autotransplants, but not mice with subcutaneous or intramuscular transplants, had greater antibody responses compared to splenectomized mice (p less than 0.05). Antibody responses were elevated only in mice autotransplanted with 50% or more of the original splenic mass. Since autotransplantation of splenic tissue augments the antibody response to pneumococcal capsular polysaccharides, the combination of splenic autotransplantation and pneumococcal vaccination may confer more protection than either modality alone in individuals who must undergo splenectomy.     

自体移植脾组织VEGF、KDR表达与血管再生的实验研究

目的 研究自体移植脾组织血管再生及VEGF、KDR表达规律，阐明VEGF、KDR对移植脾组织血管再生的调控作用，为脾脏外科临床及实验研究提供理论依据。方法 健康Wistar大鼠70只，体重100—120g，随机分为7组，每组10只中又设脾切除自体脾移植组5只，假手术组5只，分别于术后7，14，30，60，90，120，180d进行：(1)自体移植脾组织病理学检测；(2)大鼠行主动脉插管灌注墨汁，光镜观测再生血管并采用图像分析测定其密度；(3)免疫组化抗VEGF、KDR抗体染色，图像分析定量，阐明其表达规律及与血管再生的关系。结果 (1)自体脾组织移植术后7d即有血管从大网膜向脾组织内伸展，移植脾组织内血管密度逐渐增大，至术后180d血管再生接近正常；(2)自体脾组织移植术后7d、14d，VEGF、KDR阳性染色细胞密度迅速升高，术后60d达高峰，以后逐渐降低，至术后180d VEGF、KDR阳性染色细胞密度趋向正常。结论 自体脾组织大网膜内移植术是简便有效的脾移植方法；移植脾组织新生血管由大网膜再生而来；术后移植脾组织内VEGF、KDR表达量升高，促进血管形成，血管再生完成后恢复正常水平。     

Immunologic function against infection in splenic autotransplanted mice

The increasing recognition of the danger of overwhelming postsplenectomy infection (OPSI) has led surgeons to attempt to maintain splenic function after spleen injury. One technique they use when splenorrhapy or partial splenectomy are not feasible is the deliberate autotransplantation of splenic tissue. But the amount of splenic tissue necessary to prevent OPSI remains controversial, and opinions differ about the importance of the location and size of the splenic fragments implanted. The mice were divided into five groups, I. splenectomy, II. splenectomy +30% of the spleen implanted intraperitoneal site, III. splenectomy +50% implanted intraperitoneally, IV. splenectomy +50% implanted subcutaneously and V. Sham operation. This study assessed the blood flow of the splenic tissue, increasing weight of splenic mass, histology, the serum level of the immunoglobulins (IgG, IgA, and IgM), pneumococcal antibody titers after vaccination, and survival after intravenous pneumococcal challenge. This study demonstrated that intraperitoneal transplantation showed better regeneration and afforded better protection from OPSI than subcutaneous transplantation. And 30 to 50 percent of the whole splenic tissue mass protected against experimental pneumococcal sepsis. The splenic autotransplants developed in volume and blood supply after 8 weeks, and immunologic function against infection recovered at the same time.     

Improved survival with splenic autotransplantation and fibronectin therapy following endotoxin administration in rats

The risk of overwhelming infections is greatly increased after splenectomy. In this experimental study in rats, we investigated whether the administration of fibronectinrich cryoprecipitate can improve the survival rate of splenectomized autotransplanted rats subjected to an intravenous challenge with endotoxin. Inbred Lewis rats were divided into four groups: A, splenectomy; B, splenectomy + splenic autotransplantation; C, splenectomy, splenic autotransplantation + fibronectin treatment, and D, sham. Five months after surgery, rats were challenged intravenously with Escherichia coli endotoxin. Immunoglobulin (IgG, IgM, IgA), complement and fibronectin levels were measured before surgery and endotoxin challenge, and 48 h after endotoxin challenge. The survival rate of splenectomized rats was not significantly improved by autotransplantation of splenic tissue, but was significantly (p less than 0.05) improved by autotransplantation and fibronectin treatment. The levels of fibronectin, immunoglobulins and/or complements were significantly decreased after endotoxin challenge in control and in autotransplanted fibronectin-treated rats. The survival improvement of autotransplanted rats treated by fibronectin is probably due to increased endotoxin phagocytosis and clearance.     

Experimental splenosis: a comparative study in rats

The growth of the splenic remnant after partial splenectomy and autogenous splenic implants was compared in immature rats. Implants placed in the subcutaneous pouch of the anterior abdominal wall and the retroperitoneal space had none or minimal regeneration. Splenulus formed in the omental wrap were small, multiple and the combined weight was less than the original graft tissue, and more ectopic splenulus and intra-abdominal adhesions were formed. Splenic remnants after three-quarter splenectomy with an intact blood supply grew to 30-46% of the weight of the spleen of the control; and increased in size as the animal matured.     

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.     

The value of partial splenic autotransplantation in patients with portal hypertension: a prospective randomized study.

HYPOTHESIS: Splenic autotransplantation plays a role in preserving immune function of the spleen in patients with portal hypertension and liver cirrhosis. DESIGN: Prospective randomized study. SETTING: University hospital. PATIENTS: Twenty patients (19 men and 1 woman; aged 33-80 years) suffering from portal hypertension and liver cirrhosis were randomly allocated into 2 groups. Each group consisted of 10 patients. INTERVENTIONS: All patients underwent modified Sugiura operation. In the control group, splenectomy was performed, while partial splenic autotransplantation into the retroperitoneal space was additionally completed in the splenic autotransplantation group. MAIN OUTCOME MEASURES: Serum tuftsin and IgM were measured preoperatively and 2 months after surgery. Dynamic scintigraphy with technetium Tc 99m-labeled heat-damaged erythrocytes was performed at 2-month intervals during the 8-month follow-up. RESULTS: There was no statistical difference in the mortality of the groups. The preoperative levels of serum tuftsin and IgM showed no statistical difference between groups. However, although these measures had decreased remarkably in the control group 2 months after operation (P<.001 for serum tuftsin; P =.04 for serum IgM), they remained stable in the splenic autotransplantation group (P =.25 for serum tuftsin; P =.12 for serum IgM). Four patients within the splenic autotransplantation group showed positive scanning of the transplanted splenic fragment during follow-up, whereas there was no positive scanning in the control group. CONCLUSION: Our results suggest that partial splenic autotransplantation can preserve immune function of the spleen, as measured by serum levels of tuftsin and IgM, in patients with portal hypertension and liver cirrhosis.     

Histologic study of experimental spleen transplant in rats

BACKGROUND: The objective of this paper was to demonstrate that the grafts of cervical splenic transplantation on rats using our experimental model present a normal histological appearance. METHODS: Isogenic consanguineous Lewis rats 12 weeks old and weighing 250 gr. were used. Histological findings of a group of 25 cervical splenic grafts transplanted by means of splinting vascular venous microanastomoses and a group of 25 splenic grafts autotransplanted in the omentum were compared with a control group. The specimens were assigned according to a score of 0 to 4, following Moore's histological criteria. RESULTS: All grafts in transplanted and autotransplanted groups had a score of 3 or 4. Then, all splenic grafts from the transplanted group had histological findings very similar to a normal spleen. In the autotransplantation group, the percentage of grafts with a score 3 (60%) was superior to the transplantation group (46%). However, the transplantation group presented a percentage of score 4 (54%), superior to the autotransplantation group (40%). CONCLUSIONS: In our study all grafts from the cervical spleen transplantation group had histological findings very similar to a normal spleen. The percentage of spleens with histological normality in the transplantation group was superior to the autotransplantation group. However, there was no statistical significance.     

Penicillin and natural immunity protect against postsplenectomy sepsis

Prophylactic penicillin, splenic autotransplantation, and immunization using pneumococcal vaccine have all been shown to reduce the incidence and mortality of postsplenectomy sepsis. However, little is known regarding the effect of penicillin in established infection or the effect of prior infection in either asplenic controls or animals with autotransplanted splenic tissue. An animal model with bacterial introduction via the lungs was used to investigate the effect of penicillin, splenic autotransplantation, and previous exposure to the infecting organism on the mortality of postsplenectomy sepsis. One hundred fifty-nine rats underwent either sham celiotomy, intraperitoneal splenic autotransplantation, or splenectomy. Twelve weeks postoperatively all animals were challenged using Streptococcus pneumoniae delivered transtracheally. Half of each group received procaine penicillin by intramuscular injection for 5 days beginning 24 hr post bacterial inoculation and mortality was observed. Eight weeks later surviving rats that had received penicillin were reinoculated with the same organism and mortality was again observed. Splenic autotransplantation reduced the early mortality in postsplenectomy sepsis. Prior bacterial exposure reduced the mortality in postsplenectomy sepsis, even in splenectomized animals. Treatment with penicillin produced a marked reduction in mortality even when administration was postponed for 24 hr after bacterial inoculation.     

Cellular and serological changes in the peripheral blood of splenectomized and spleen autotransplanted mice

BACKGROUND: Our department worked out a modified surgical form of spleen autotransplantation earlier, named "spleen apron method" introduced already into the clinical practice. Recently we tested the immunological changes in a group of patients autotransplanted with about 10-15% of their spleen, what was the at least always implantable amount after the severe splenic injuries. In the current work we aimed at measuring some cellular and serological changes in the peripheral blood of splenectomized and spleen autotransplanted inbred mice two and eight months after the operations in order to get more unambiguous results than that we could obtain in our patients with this technique. MATERIALS AND METHODS: We divided 96 two months old Balb/c female mice into eight groups (n = 12/group). The group of controls, sham operated, splenectomized and autotransplanted animals with two and eight months of survival time after the operations. During the autotransplantation we inserted the same amount of spleen, five slices, "chips," about 10-15% of total mass of spleen, into the greater omentum similarly as it was used in the patients. The concentration of serum proteins were measured by laser nephelometry. The lymphocyte subsets were analyzed by flow cytometry. RESULTS: We found that two months after the operations the number of CD 19+ B-cells increased in the splenectomized but decreased in the autotransplanted animals. Eight months after the operations the number of both CD3+ T and CD19+ B lymphocytes decreased both in the splenectomized and autotransplanted animals compared to the controls and sham operated mice. However, the numbers of T and B cells were slightly but not significantly higher in the autotransplanted than in the splenectomized mice. The serum level of IgM was also decreased in the splenectomized and autotransplanted mice at both time points, however, eight months after the operations the concentration of IgM was significantly higher in the autotransplanted group than in the splenectomized animals. CONCLUSION: The effects of autotransplanted "chips" were different at the various ages of the animals. Additionally, they showed some immunological benefit being quantitatively in accordance to the amount of the transplanted spleen. The elevated level of serum IgM what we found in the autotransplanted mice even with this amount of transplanted spleen eight months after the operations, however, might have the potentially greatest importance compared to splenectomy. These experiments can prove that the attempts for autotransplantation may have real perspectives but their efficacy depends on the amount of the successfully transplanted (saved) mass of spleen.     

Hematological, hemorheological, immunological, and morphological studies of spleen autotransplantation in mice: preliminary results

Using a spleen autotransplantation model, we conducted hematological, hemorheological, immunological, and morphological studies in mice 6 weeks after splenectomy. Sixty male and female A/J inbred mice were equally divided into 3 groups: 1) SE group, splenectomy was performed; 2) AU group, spleen chips were autotransplanted into the omentum without vascular anastomosis following splenectomy; and 3) C group (controls), no intervention in these mice. At postoperative week 6, the following studies were performed: 1) measurement of hematological parameters; 2) hemorheological studies, including relative cell transit time (RCTT) and fibrinogen levels; and 3) activity of peripheral phagocytes, measured by zymozan-induced chemiluminescence, which was calculated in stimulation index values (SI). In addition, histological investigations of autotransplants were conducted. Erythrocyte mean cell volume and platelet counts, RCTT, fibrinogen levels, and activity of phagocytes were significantly higher in the SE group, compared to those in the C group. In the AU group, these parameters were similar to those in the C group. Morphologically, the transplanted spleen showed normal histology. These data indicate that the transplanted spleens restored their function. We conclude that spleen autotransplantation reserves the normal morphology of spleen and restores most of the spleen's hematological, hemorheological, and immunological functions. Both SI index and erythrocyte deformability can be an informative detection of decreasing splenic function. These data suggest that spleen autotransplantation may provide a useful tool to prevent complications following splenectomy in a clinical setting.     

Autotransplantation of Spleen Mitigates Drug-Induced Liver Damage in Splenectomized Mice

Purpose: The spleen presents numerous functions, including the production of immunoglobulins and blood filtration, removing microorganisms and cellular debris. The spleen also has anatomical and functional relationship with the liver, but there are few studies on this topic. The aim of this study was to assess the effect of splenectomy and autologous spleen transplantation on both filtering functions of spleen and acetaminophen-induced hepatotoxicity. Materials and Methods: Fifty-two BALB/c mice were randomized into four groups: splenectomized; splenectomy and splenic autotransplantation in the greater omentum; sham operated control; and non-operated control. At day 7th, 14th, and 28th after surgery, splenic filtration was assessed by counting Howell-Jolly bodies (HJB) and pitted red cells (PIT). The animals received 400 mg/kg acetaminophen by gavage at day 28^th and after 12 or 24 hours were euthanized for evaluation of splenic and hepatic morphology. Results: The splenectomized group demonstrated reduced filtration of HJB and PIT in all analyzes, while the autotransplanted group developed progressive recovery of function after the 14th day. At day 28 after surgery the implants showed similar histology in comparison to normal spleen. Liver histology showed more intense centrilobular necrosis in splenectomized group in comparison to the others, suggesting a protective role of spleen in acetaminophen-induced liver injury. Conclusions: Splenic implants showed structural and functional recovery, demonstrating the ability of autologous implant to rescue filtering function of intact spleen. Furthermore, the integrity of splenic function appears to influence liver morphology, since the presence of the splenic implants mitigated the effects of chemically-induced liver damage.