Original Article Hematopoietic Stem Cells Derived From Adult Donors Are Not a Source of Pancreatic -Cells in Adult Nondiabetic Humans Alexandra E. Butler, 1 Andrew Huang, 1 P. Nagesh Rao, 2 Anil Bhushan, 1 William J. Hogan, 3 Robert A. Rizza, 4 and Peter C. Butler 1 OBJECTIVE—Type 1 and type 2 diabetes are characterized by an 98 and 65% loss of pancreatic -cells, respectively. Efforts to reverse either form of diabetes increasingly focus on the possibility of promoting -cell replacement and/or regeneration. Islet transplantation has been explored, but it does not provide long-term insulin independence. One possible source of -cell regeneration is hematopoietic stem cells. In mice, there are conflicting data as to whether hematopoietic stem cells contrib- ute to pancreatic -cells. We sought to establish whether hema- topoietic stem cells (derived from adult donors) transdifferentiate into pancreatic -cells in adult humans. RESEARCH DESIGN AND METHODS—We addressed this in 31 human pancreata obtained at autopsy from hematopoietic stem cell transplant recipients who had received their transplant from a donor of the opposite sex. RESULTS—Whereas some donor-derived cells were observed in the nonendocrine pancreata, no pancreatic -cells were identi- fied that were derived from donor hematopoietic stem cells, including two cases with type 2 diabetes. CONCLUSIONS—We conclude that hematopoietic stem cells derived from adult donors contribute minimally to pancreatic -cells in nondiabetic adult humans. These data do not rule out the possibility that hematopoietic stem cells contribute to pan- creatic -cells in childhood or in individuals with type 1 diabetes. Diabetes 56:1810–1816, 2007 T ype 1 and type 2 diabetes are characterized by an 98 and 65% defect in -cells, respectively. There is evidence of ongoing -cell turnover in human subjects with long-standing type 1 diabe- tes (1). This raises the question of the origin of these newly derived -cells and whether they might be sufficient in number to be a source of -cell regeneration if the mechanisms leading to -cell destruction could be over- come. Bone marrow stem cells and their splenic deriva- tives have been proposed as a potential source of pancreatic -cells. In mice, both bone marrow stem cells and their splenic stem cell derivatives have been reported to generate pancreatic -cells (2), although these findings have subsequently been challenged (3,4). In the present study, we sought to establish whether hematopoietic stem cells give rise to pancreatic -cells in adult humans. To accomplish this, we examined human pancreata obtained at autopsy from 31 recipients of hema- topoietic transplants from opposite-sex donors. Survival of hematopoietic recipients ranged from 13 to 1,235 days after hematopoietic stem cell transplant. In all cases, as a positive control, spleen from each hematopoietic stem cell transplant recipient was examined to verify that engraft- ment had occurred. RESEARCH DESIGN AND METHODS Institutional review board approval for this study was obtained from the Mayo Clinic. The Mayo Clinic blood and marrow transplant database was searched to identify patients who, during the course of their life, had received a hematopoietic stem cell transplant from a sex-mismatched donor (W.H.). Cases were included only if a full autopsy had been performed within 12 h of death and whether there was stored pancreatic tissue of adequate size and quality. Of the 31 patients, 26 received a bone marrow– derived graft, 4 received a peripheral blood– derived graft, and 1 patient received a combina- tion of both peripheral blood– and bone marrow– derived stem cells. There were 23 matched related sibling donors, 3 mismatched family donors, and 5 unrelated donors matched at the antigen level for HLA A, B, and DR. One patient who initially received a bone marrow graft from an identical HLA sibling received a second peripheral blood-derived graft from the same donor without conditioning 3 years later for aplasia in the context of graft-versus- host disease. Patients were treated according to institutional guidelines, with regard to graft-versus-host disease prophylaxis and infectious disease prophylaxis. The present human study also included two patients with documented diabetes (fasting plasma glucose 126 mg/dl) and one patient with impaired fasting glucose (fasting plasma glucose 110 –125 mg/dl) before hematopoietic stem cell transplant. The patients with diabetes survived 90 and 94 days post– hematopoietic stem cell transplant, while the patient with impaired fasting glucose survived 29 days post– hematopoietic stem cell transplant. Pancreatic tissue processing. Tail of pancreata and a random sample of spleen were obtained at autopsy, and, after overnight fixation in 10% formaldehyde, were embedded in paraffin. For the purpose of the present study, two 4 mol/l sections from paraffin blocks containing pancreata and spleen from 32 cases were obtained and mounted on Fisher brand Ink Jet White IJL-6109-Plus-600621 charged slides (Fisher Cat no. 12550109; Fisher Scientific, Pittsburgh, PA). One section from each case was stained with hematoxylin and eosin and examined (A.E.B.) to exclude autolysis, with none being excluded on this basis. The second section from each case was first analyzed by fluorescent in situ hybridization (FISH) to detect X and Y From the 1 Larry L. Hillblom Islet Research Center, University of California Los Angeles, Los Angeles, California; the 2 Department of Pathology and Labora- tory Medicine, University of California Los Angeles, Los Angeles, California; the 3 Division of Hematology, Mayo Clinic, Rochester, Minnesota; and the 4 Division of Endocrinology, Diabetes, Metabolism and Nutrition, Mayo Clinic, Rochester, Minnesota. Address correspondence and reprint requests to Peter C. Butler, Division of Endocrinology, University of California Los Angeles, Larry L. Hillblom Islet Research Center, 900 Veteran Ave., 24-130 Warren Hall, UCLA, Los Angeles, CA 90095-7073. E-mail: pbutler@mednet.ucla.edu. Received for publication 29 September 2006 and accepted in revised form 17 April 2007. Published ahead of print at http://diabetes.diabetesjournals.org on 24 April 2007. DOI: 10.2337/db06-1385. FISH, fluorescent in situ hybridization; FTIC, fluorescein isothiocyanate. © 2007 by the American Diabetes Association. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact. 1810 DIABETES, VOL. 56, JULY 2007