Recent studies reported that bone marrow cavity offers a widely distributed and well-vascularized micro-environment which is a considerable implantation site for bioartificial pancreas (BAP). In this study, the in vivo performance of BAPs in bone marrow was further demonstrated in a spontaneous diabetes animal. Mouse insulinoma cells encapsulating in agarose gel were enclosed in a calcium phosphate cement chamber to create a BAP. Ten BAPs were implanted into the femur bone marrow cavity of a diabetic feline. The preprandial blood glucose level, 2 h glucose curve, serum C-peptide level and physiological conditions of the recipient were recorded perioperatively. Results showed that the cat still suffered from hyperglycemia postoperatively. However, the physiological conditions of feline were improved with an increase of serum C-peptide level. The peak point of 2 h glucose curve decreased from 400 to 165290 mg/dl. The efficiency of exogenous insulin extended from 2 to 10-14 h postoperatively which reveals that the implanted BAPs had partial function. This case report revealed that BAPs implanted in the bone marrow cavity for the spontaneous diabetic is effective. The implanted BAPs provided therapeutic benefit despite sustained hyperglycemia. Further study shall be considered to improve the outcomes of BAPs transplantation. (C) 2010 Elsevier Inc. All rights reserved.