Abstract 3991: A novel methodology for the utilization of intramedullary aspirates from total joint arthroplasty [TJA]: a low-cost, alternative source of normal hematopoietic cells [NHC]

Proceedings: AACR 101st Annual Meeting 2010‐‐ Apr 17‐21, 2010; Washington, DC INTRODUCTION: The procurement of NHC, for use as controls in hematologic research, is often problematic. The once-conventional source of a voluntary bone marrow [BM] aspirate is now widely prohibited, forcing researchers to purchase these specimens from only a few retailers worldwide. Having to both compensate a donor and generate a profit, the current cost of healthy, human BM is, on average, $40/mL or $4000 for a typical experiment [3 Donors X 50mL]. These specimens are also plagued by several other shortcomings, including: long and erratic lead times, legal restrictions which prohibit age-matching, and variability in their preanalytical handling due to shipping. More than 750,000 joint replacements are now performed annually in the United States alone, and as part of the preparation for these procedures, femoral BM is commonly aspirated and discarded; however, this phenomenon is largely overlooked as a source of controls due to the excess adipocytes found in adult long bones. As such, we sought to develop a method for the acquisition of NHC from the intramedullary aspirates routinely discarded during TJA. METHODS: In collaboration with the Department of Orthopedics and IRB at the Massachusetts General Hospital, Boston, we obtained the discarded intramedullary aspirates of 50 patients undergoing primary, elective TJA of either the hip or knee [Ratio-1:1]. Eligible patients were free of active leukemia or lymphoma and a history of pertinent illness. Aspirates were collected via an in-line sputum trap and standard medical suction just prior to the placement of the femoral prosthesis, heparinized [50 U/mL] and stored at 4oC for < 3 hours before being processed. A novel, hydrophobicity-based methodology was developed to remove the bone, reticulocytes, and excess adipose which dominate these specimens, while sparing the mononuclear cell compartment [MNC]. Specific lymphocytes were immunomagnetically selected, analyzed for purity by flow cytometry [FACS] and compared to commercial BM. RESULTS: Hips produced a median 593×106 MNC (SD=54×106), knees yielded 387×106 MNC (SD=54×106); viability was > 93% by Trypan Blue. The median for commercial marrow was 354×106 MNC (SD=24×106) [n=12,25mL]. Selection of CD34+, CD19+, CD138+ and CD3+ cells from processed TJA BM resulted in substantial populations of enriched cells; the purity of each subset was determined to be > 90% by FACS. Age-matching to hematologic malignancies [median age at diagnosis: 67 - NCI's SEER database] was possible with TJA controls, the median age was 66.6, whereas for commercial donors, it was 27.2 [n=37]. CONCLUSIONS: Using our novel methodology, the intramedullary aspirates routinely discarded during primary, elective TJA represent a viable, and underutilized, reservoir of NHC, and are superior to purchased marrow specimens in terms of cost, yield and appropriateness. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3991.