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

Spleen: Reparative Regeneration and Influence on Liver

This review considers experimental findings on splenic repair, obtained in two types of small animal (mouse, rat, and rabbit) models: splenic resections and autologous transplantations of splenic tissue. Resection experiments indicate that the spleen is able to regenerate, though not necessarily to the initial volume. The recovery lasts one month and preserves the architecture, albeit with an increase in the relative volume of lymphoid follicles. The renovated tissues, however, exhibit skewed functional profiles; notably, the decreased production of antibodies and the low cytotoxic activity of T cells, consistent with the decline of T-dependent zones and prolonged reduction in T cell numbers. Species-specific differences are evident as well, with the post-repair organ mass deficiency most pronounced in rabbit models. Autotransplantations of splenic material are of particular clinical interest, as the procedure can possibly mitigate the development of post-splenectomy syndrome. Under these conditions, regeneration lasts 1-2 months, depending on the species. The transplants effectively destroy senescent erythrocytes, assist in microbial clearance, and produce antibodies, thus averting sepsis and bacterial pneumonia. Meanwhile, cellular sources of splenic recovery in such models remain obscure, as well as the time required for T and B cell number reconstitution.

Persistent changes in circulating white blood cell populations after splenectomy

The effect of splenectomy on the incidence of infections and thromboembolisms has been investigated thoroughly. Nevertheless, the long-term effects of splenectomy on immunological profile and circulating blood counts have not been described before. To study such long-term effects, we analysed several parameters in splenectomised trauma patients and compared the results of this group ("otherwise healthy patients") to patients with a specific underlying disease. We measured platelet count, leukocytes and differential, lymphocyte subsets, serum levels of immunoglobulins, and complement pathways in 113 patients. Indications to perform a splenectomy were trauma (n = 42), Hodgkin lymphoma (n = 24), hereditary spherocytosis (n = 21), and immune thrombocytopenia (n = 26). In trauma patients lymphocytes and lymphocytes subsets were particularly elevated compared to normal population values. Splenectomised patients with Hodgkin lymphoma had significant lower numbers of T lymphocytes than trauma patients. Significant increases in platelets, leukocytes, and monocytes were observed in patients with hereditary spherocytosis. Occurrence of MBL genotype was different in ITP patients than in other splenectomised groups and the normal population. In splenectomised patients (> 4 years), platelet counts and lymphocyte subsets are increased which persist over time. As a result, these blood counts in splenectomised patients differ from reference values in the normal population.

Haematological and biochemical characteristics of the splenic effluent blood in schistosomal patients undergoing splenectomy

OBJECTIVE

To assess hematological and biochemical features of splenic effluent blood and their influence on the rise of hematological values after splenectomy.

METHODS

we studied 20 patients undergoing surgical treatment for schistosomatic portal hypertension. We collected blood samples for CBC, coagulation, bilirubin and albumin in the splenic vein (perioperative) and peripheral blood (immediately pre and postoperative periods).

RESULTS

the splenic blood showed higher values of red blood cells, hemoglobin, hematocrit, platelet count, total leukocytes, neutrophils, lymphocytes, monocytes, eosinophils and basophils, as well as reduction of laboratory coagulation parameters in relation to peripheral blood collected preoperatively. In the postoperative peripheral blood there was an increase in the overall leukocytes and in their neutrophil component, and decreased levels of basophils, eosinophils and lymphocytes. The other postoperative variables of complete blood count and coagulation tests were not different compared with the splenic blood. The albumin values were lower postoperatively when compared to preoperative and splenic blood. There were higher values of direct bilirubin in the postoperative period when compared with the preoperative and splenic blood. Postoperative indirect bilirubin was lower compared to its value in the splenic blood.

CONCLUSION

hematological and biochemical values of splenic effluent blood are higher than those found in peripheral blood in the presence of schistosomal splenomegaly. However, the splenic blood effluent is not sufficient to raise the blood levels found after splenectomy.

[The spleen in experimental surgery]

The injured but functionally intact spleen can be saved with various surgical techniques. Two of these techniques were developed in our department: partial spleen resection by embracing suture line, and spleen autotransplantation by implantation of spleen chips between the sheets of the greater omentum, the so called "spleen-apron" technique. Functional and structural postsurgical follow-up investigations were developed in the last three decades, including comprehensive laboratory tests (hematological, hemostaseological, hemorheological, enzymological, routine chemical, immunological), imaging procedures (abdominal US, scintigraphic methods, SPECT, as well as NanoSPECT/CT in the last years) with morphological analysis (conventional histological, immunohistochemical, electonmicroscopical), as well as the investigation of the role of hemopoetic stem cells. These investigations confirm the viability of spleen autotransplantation. The implanted spleen chips are able to restore the splenic functions partially following remodellation and recolonisation after neovascularisation. It is a critically important process in the prevention of overwhelming post-splenectomy infection and DIC. This paper summarizes the most important principles and the main conclusions of different experimental animal models.

Complications of splenectomy

Surgical removal of the spleen, splenectomy, is a procedure that has significantly decreased in frequency as our understanding of the infectious complications of the asplenic state increased. The full spectrum and details of splenic function, however, have yet to be fully outlined. As a result, our comprehension of the long-term consequences of splenectomy remains incomplete. We review the evidence relating to the effects of splenectomy on infection, malignancy, thrombosis, and transplantation. Perhaps the best-defined and most widely understood complication of splenectomy is the asplenic patient's susceptibility to infection. In response to this concern, novel techniques have emerged to attempt to preserve splenic function in those patients for whom surgical therapy of the spleen is necessary. The efficacy of these techniques in preserving splenic function and staving off the complications associated with splenectomy is also reviewed in this article.

Spleen autotransplantation. Morphological and functional follow-up after spleen autotransplantation in mice: A research summary

In 1986, we started the research on spleen surgery aimed at saving the splenic mass after its traumatic injury, with elaboration of special resection and autotransplantation techniques. The researches started on mongrel dogs and were continued on inbred mice and beagle dogs with complex histological, imaging, and laboratory investigations, following-up the function and the regeneration of autotransplanted spleen chips. Performing research on mice provided more immunological methods, such as lymphocyte subsets, immunoglobulin levels, and monitoring the phagocytic functions. Researches showed evidence also on the presence of apoptosis, furthermore, stem cell studies on regeneration and functional restoration of the spleen chips are in progress. Our results contributed to two multidisciplinary guidelines in Hungary: (1) One of them is under preparation and underlines the importance of spleen saving methods after traumatic splenic injury; (2) The second guideline shows that hemorheological changes can be early indicators of the increased sensitivity to postsplenectomy infections.