PURPOSETo evaluate intravascular xenotransplantation of macroencapsulated pancreatic islet cells in the process of the treatment of diabetes mellitus type 1 without immunosuppressive therapy.MATERIAL AND METHODSXenogenic intravascular transplantation was performed in 19 patients with diabetes mellitus (type 1) having high insulin demand and frequent hypo- and hyperglycemic comas without immunosuppressive therapy. The culture was obtained from 3rd trimester rabbit fetuses. Cell culture suspension was encapsulated into microporous macrocapsule made of nylon and grafted into the deep femoral artery or the forearm cubital vein after performing arteriovenous anastomosis.RESULTSFor 2 years after transplantation, positive results were observed in 14 recipients (73.7%). The total decrease of insulin demand was 60-65%, and hypo- and hyperglycemic comas disappeared completely, while C-peptide and immunoreactive insulin levels significantly increased, reversely correlating with the fructosamin level, as a protein glycation marker.CONCLUSIONSXenotransplantation of pancreatic islet cells with their subsequent grafting into the vascular lumen creates double immune isolation and allows overcoming acute and chronic graft rejection without immuno-suppressive therapy. It considerably decreases insulin demand, compensates hypo- and hyperglycemic conditions, makes the course of diabetes stable, and improves the quality of the patients' life.