Timothy D. O'Brien, DVM, PhD

Professor and Division Head, Comparative Pathology, Department of Veterinary Population Medicine (VPM)
Timothy O'Brien


Office Address

Veterinary Diagnostic Labs 220F VDL
1333 Gortner Ave
St Paul, MN 55108
United States


Leadership Team Member, Stem Cell Institute
Member, Masonic Cancer Center (MCC)
Member, Institute for Engineering in Medicine
Faculty, Masters Program in Stem Cell Biology


DVM, University of Minnesota, 1978

PhD, University of Minnesota, 1985

BS, University of Minnesota, 1976

Licensures and Certifications

Diplomate, American College of Veterinary Pathologists (Anatomic Pathology, 1984)

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Awards & recognition

  • College of Veterinary Medicine Mark of Excellence Award for Research, 1998
  • Society of Phi Zeta National Research Award, 1984


Research summary/interests

  • iPSC-derived brain organoids—Using a novel biomimetic hydrogel, we have developed an improved, robust, and GMP-amenable method for generating brain organoids from human induced pluripotent stem cells. We are actively pursuing applications of these organoids for the study of human neurological conditions such as Parkinson’s disease, Alzheimer’s disease, and childhood cerebral adrenoleukodystrophy, as well as their use as a source of therapeutic cells for transplantation to patients with Parkinson’s disease
  • Diabetes mellitus—We are developing a novel biomaterial to provide a supportive microenvironment to enhance function and extend survival of pancreatic islets for use in pancreatic islet transplantation.


Selected publications

  • Lindborg B, Brekke JH,Scott CM, Chai Y-W, Stuart MT, Sandquist L, Kokkoli E, O’Brien TD: A novel chitosan-hyaluronan based hydrocolloid supports in vitro culture and differentiation of human mesenchymal stem/stromal cells (MSC). Tissue Eng Part A 21:1952-1962, 2015. doi: 10.1089/ten.TEA.2014.0335. Epub 2015 Apr 20. PMID:25748146
  • Modiano JF, Lindborg BA, McElmurry RT, Lewellen M, Zamora EA, Schaack J, Bellgrau D, O’Brien TD, Tolar J: Mesenchymal stromal cells inhibit syngeneic murine anti-tumor immune responses by attenuating inflammation and reorganizing the tumor microenvironment. Cancer Immunol Immunother 2015 Nov; 64(11):1449-60. doi: 10.1007/s00262-015-1749-6. Epub 2015 Aug 7. PMID: 26250807
  • Khatri M, O’Brien TD, Chattha KS, Saif LJ: Porcine lung mesenchymal stromal cells possess differentiation and regulatory properties. Stem Cell Res Ther 2015 Nov 11;6:222. doi: 10.1186/s13287-015-0220-0. PMID:26560714
  • Lindborg BA, Brekke JH, Ulrich C, Haider K, Subramaaniam S, Venhuizen S, Kokkoli E, Dutton J, Tolar J, O’Brien TD: Rapid induction of cerebral organoids from human induced pluripotent stem cells using a chemically defined hydrogel and defined cell culture medium. Stem Cells Translational Medicine, 2016 Jul;5(7):970-9. doi: 10.5966/sctm.2015-0305. Epub 2016 May 13. PMID: 27177577
  • Weegman BP, Taylor MJ, Baicu SC, Mueller KR, O’Brien TD, Wilson J, Papas KK: Plasticity and aggregation of juvenile porcine islets in modified culture for xenotransplantation: Preliminary Observations. Cell Transplant 25:1763-1765, 2016 Apr 22. [Epub ahead of print] PMID:27109912
  • Seelig DM, Ito D, Foster CL, Yoon UA, Breen M, Burns LJ, Bachanova V, Lindblad-Toh K, O’Brien TD, Schmechel SC, Rizzardi AE, Modiano JF, Linden MA: Constitutive activation of alternative nuclear factor kappa B pathway in canine diffuse large B-cell lymphoma contributes to tumor cell survival and is a target of new adjuvant therapies. Leukemia & Lymphoma. 8:1-9, 2016. [Epub ahead of print] PMID:27931134
  • Weiskopf K, Anderson KL, Ito D, Schnorr PJ, Tomiyasu H, Ring AM, Bloink K, Efe J, Rue S, Lowery D, Prohaska S, McKenna KM, Cornax I, O’Brien TD, O’Sullivan MG, Weissman IL, and Modiano JF:CD47 blockade synergizes with anti-CD20 passive immunotherapy for the eradication of canine diffuse large B-cell lymphoma. Cancer Immunol Res.4(12):1072-1087, 2016. PMID:27856424
  • Pei H, Fu H-Y, Hirai H, Lee K, Zhao L, Cho DS, O’Brien TD, Dutton J, Verfaillie CM, Hu W-S: Generation of induced pluripotent stem cells from Chinese hamster embryonic fibroblasts. Stem Cell Research, 2017 May;21:132-136. doi: 10.1016/j.scr.2017.04.010. Epub 2017 Apr 21. PMID: 28677528
  • Scott MC, Temiz NA, Sarver AE, LaRue RS, Rathe SK, Varshney J, Wolf NK, Moriarity BS, O’Brien TD, Spector LG, Largaespada DA, Modiano JF, Subramanian S, Sarver AL: Immune cell transcript levels, metastatic progression and survival in osteosarcoma: A comparative transcriptome analysis. Cancer Res. 2017 Oct 24. pii: canres.0576.2017. doi: 10.1158/0008-5472.CAN-17-0576. [Epub ahead of print] PMID:29066513
  • Syedian ZH, Graham ML, Dunn TB, O’Brien TD, Johnson SL, Schumacher RJ, Tranquillo RT:Preclinical study of a completely biological “Off-the Shelf” arteriovenus graft. Science Translational Medicine, 2017 Nov 1;9(414). pii: eaan4209. doi: 10.1126/scitranslmed.aan4209. PMID: 29093182


Teaching areas

  • Veterinary Basic Pathology—Amyloidosis and transmissible spongiform encephalopathies
  • Surgical and comparative pathology


Clinical interests

  • Surgical pathology including oncologic pathology and dermatopathology