OBJECTIVES

Because of immune system deficiencies and associated overwhelming postsplenectomy infection, splenic preservation at time of splenectomy by splenorrhaphy, partial resection or autotransplantation is attempted. Splenosis has been shown to maintain some immune and reticuloendothelial functions, but the extent of short and long term beneficial effects of splenosis is undetermined. This canine study uses Angiogenin to enhance volume and function of splenosis.

MATERIALS

Nine dogs undergoing splenectomy were divided into three groups, with 3 dogs each, based on the type of autotransplantation of the splenic tissue. In Group 1, an average of 3.5 mg of splenic fragments (2 mm3) were implanted in the peritoneal cavity and abdominal wall. In Group 2, the splenic fragments were immersed in 1ml saline containing 5µm of angiogenin for 15 min before implanted to the peritoneal cavity and abdominal wall. Besides same as in Group 2, an intramuscular injection of 0.5µm angiogenin was given weekly to the animals in Group 3 for 12 weeks. To evaluate for splenosis, 6 months after surgery scintigraphic abdominal and chest scanning was performed using intravenous injection of 1mCi of 99mTC sulfur colloid in all dogs. Blood samples were obtained to determine the presence of Howell-Jolly bodies. Seventy-two hours after the scanning, a laparotomy was performed to harvest all residual splenic tissues in all animals. The splenic tissues were weighed and examined macroscopically and microscopically.

RESULTS

All animals were survived, but one in Group 2 died of unknown cause. Scintigraphy showed either negative (n=2) or slightly positive (n=1) in Group 1; moderately positive (n=2) in Group 2; and either strongly positive (n=2) or moderately positive (n=1) in Group 3. Relative scintigraphic activity is being calculated to compare residual splenic uptake quantitatively among the groups of dogs. Howell-Jolly bodies were detected in all groups, but less prominent in Group 3. Most of the splenic pulps were, in kidney shaped, found in the omentum. The average of harvested splenic pulps was 4.63 gm with Group 1, 5.34 gm with Group, and 7.60 gm with Group 3.

CONCLUSION

Our preliminary results indicate angiogenin enhances regeneration and growth of autotransplanted splenic tissues following splenectomy. The use of angiogenesis factor may provide a better approach to help protect asplenic and hyposplenic patients from overwhelming postsplenectomy infections.