Colorado State University Animal Cancer Center
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Nicole Ehrhart

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Name of Investigator: Nicole Ehrhart
Title: Professor, Surgical Oncology
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Contact Information:
Email Address:
Work Address (mailing): CSU Flint Animal Cancer Center
Veterinary Teaching Hospital, Campus delivery 1678
300 West Drake Road, Fort Collins, CO 80523
Office Location (Building/Room #): ACC 224
Office Phone Number: (970) 297-1218
Laboratory Location (Building/Room #): ACC 244
Laboratory Phone Number: (970) 297-4086
  Nicole Ehrhart

Biography of Investigator:
Dr. Nicole Ehrhart graduated from the University of Pennsylvania College of Veterinary Medicine in 1990. She completed an internship in general medicine and surgery at the Animal Medical Center in New York City and was accepted into a surgery residency at Colorado State University in 1991. She completed her surgical residency and Masters degree in Clinical Sciences in 1994 and became Board Certified in Surgery in 1995 during the first year of a 2 year postdoctoral Fellowship in Surgical Oncology and Orthopedic Research. Following completion of her Fellowship she was recruited in 1996 to the University of Illinois College of Biomedical Sciences as an Assistant Professor in Surgical Oncology where she remained for 6 years. In 2002, concurrent with the opening of the new Flint Animal Cancer Center at Colorado State University College of Veterinary Medicine and Biomedical Sciences, she returned to Colorado to join the faculty as a Professor of Surgical Oncology. She holds joint faculty appointments in the School of Biomedical Engineering and the Cell and Molecular Biology Programs, is a member of the Gates Regenerative Medicine Center at the University of Colorado and is a University of Colorado Cancer Center member.

Classes Taught/Currently Teaching:

  • Junior Surgery Laboratory, Laboratory Instructor
  • Oncology, Complimentary Medicine and Pain Management, Lecturer and Laboratory Instructor
  • Orthopedic and Joint Surgery, Lecturer
  • Surgical Principles Laboratory, Laboratory Instructor
  • VM645 Surgery of the Eye, Laboratory Instructor
  • VM733 Principles of Surgery, Lecturer
  • VM673 Cardiovascular and Thoracic Surgery, Lecturer
  • VM773 Small Animal Medicine and Surgery, Lecturer
  • VM796F Problem Based Learning, Facilitator
  • VS612 Plastics and Reconstructive Surgery, Lecturer
  • VS650 Comparative Abdominal Surgery, Lecturer
  • VS681 Comparative Pain Medicine, Lecturer
  • VS681 Comparative Pain Medicine II, Lecturer


Research Focus:
Surgical Oncology

Limb Preservation:

  • Animal Models for Cancer and Orthopedic Research
  • Gene Delivery and Tissue Engineering
  • Allograft Science
  • Osteoneogenesis and Distraction Osteogenesis

Name of Laboratory:
Laboratory of Comparative Musculoskeletal Oncology and Traumatology

Laboratory Personnel:
Lab Manager: Laura Chubb, BS

Ruth Rose, Post Doctoral Studies, DVM, DACVS
Area of Study: Osteosarcoma

Megan Aanstoos-Ewen, MS, Ph.D. Candidate
Area of Study: Osteosarcoma, Mesenchymal Stromal/Stem Cells

Kaitlyn McNamara, MS Student
Area of Study: Murine Immunohistochemistry, Mesenchymal Stromal/Stem Cells

Morgan Woodard, DVM Student
Area of Study: Osteomyelitis


Laboratory Expertise
The Laboratory of Comparative Musculoskeletal Oncology and Traumatology (Director: Dr. Nicole Ehrhart) is housed within the Flint Animal Cancer Center at Colorado State University’s James L. Voss Veterinary Medical Center: A 2000 ft2 laboratory has been dedicated to cell and tissue culture work, and small animal models. The equipment within this facility includes: Class IIA biological safety laminar flow hood, humidified incubator (5% CO2), centrifuge, -80oC freezer (storing samples until assayed), antibiotic bead molds, automated pipettor, microscope (especially for cell cultures), refrigerators, plate readers, pH meters, and all culture supplies (culture media and additives, cryotubes and culture plates). The Musculoskeletal Oncology Laboratory is home to a Xenogen IVIS 100 series bioluminescence imaging system which has the ability to track genetically modified cells in vivo. Imaging Laboratory: The imaging suite within the lab has been dedicated to the histomorphometry and histopathology of various tissues, including bone. The primary analysis tool is Bioquant software and dark field and fluorescence microscopy. Laboratory personnel are experienced in all basic bench skills including ELISA analysis, immunohistochemical staining, cell culture, etc. Surgical Suite: Also within the Laboratory of Comparative Orthopedic Oncology and Traumatology is space dedicated for surgeries involving small animal models such as rabbits, rats, and mice. The suite is equipped with operating table, heating pads, surgical and anesthesia equipment, and is staffed by individuals trained in veterinary care. All PRP/SVF preparations, serum and synovial fluid storage and ELISA analyses for serum and synovial biomarkers will take place in these facilities. A full time laboratory technician (Laura Chubb) oversees and coordinates equipment operation, maintenance and daily research activities within the lab.

The hospital houses 8 state-of-the-art operating rooms for large animal surgeries. These facilities are supported by a full time OR staff including certified veterinary anesthetists and scrub nurses. Surgical equipment includes advanced orthopedic saws, drills and fixation systems, a C-arm for intra-operative imaging, an operating microscope and cardiopulmonary by-pass. In addition to the surgical facilities, there are advanced imaging facilities for large and small animal studies including digital radiology with electronic archive, a 1.5 T MRI, PET/CT, gamma camera, fluoroscopy and interventional radiology suites. Recovery suites are monitored by certified veterinary technicians.


Available Specialized Laboratory Equipment:
Tissue Culture, Cell Storage & General Laboratory Equipment

  1. LABCONCO Purifier Class II Biosafety Cabinet Tissue Culture Hood (Delta Series) (n=2) - Model 36200
  2. Thermo Orion Water Jacketed (19 Gallon) CO2 Incubator (n=2) - Model 5060
  3. Fischer Hamilton SAFEAIRE Chemical Fume Hood - Model 54L0405
  4. VWR Scientific Produts (4°C) Refrigerator
  5. Fridgidaire (-20°C) Freezer
  6. Thermolyne Locator 4 Cryo Biological Storage System w/ attached Thermolyne Liquid Notrogen Monitor - Model CY50935
  7. Forma Scientific (-80°C) Freezer
  8. Beckman Coulter Allegra 6R Centrifuge
  9. Spectrafuge 16M Centrifuge
  10. VWR International Water Bath - Model 1235PC
  11. Corning Stirrer/Hot Plate - Model PC400
  12. Minisonic Ultrasonic Cleaner - Model 2510R-DTH
  13. Labnet International, Inc Vortex Mixer - Model 50100
  14. Invitrogen Countess Automated Cell Counter
  15. Shandon Lipshaw Slide Staining Chamber
  16. Mettler Toledo Balance - Model AG104
  17. VWR Rocking Platform
  18. Sharp Carousel Microwave


Small Animal Anesthesia & Surgical Facilities:

  1. Ohmeda Isotec 3 (BOC Heath Care) Isofluorane Gas Vaporizor (n=2)
  2. Stainless Steel Surgical Table


Image Acquisition & Analysis:

  1. Xenogen IVIS 100 System (PerkinElmer)
  2. Live Image 4.2 Software, Advanced Acquisition & Analysis Software for IVIS 100 System
  3. BioTek Synergy HT Multi-Mode Microplate Reader - Model SIAFRT (n=2)
  4. Osteomeasure XP Version 1.01 Bone Histomorphometry Software
  5. EVOS XL Core Imaging System for Transmitted Light Applications
  6. BioRad Spectrophotometer Smart SpecTM 3000


Computational Resources:

  1. Dell Optiplex Workstation - 745
  2. HP Workstation – Z220


Graduate/Post-Graduate Research Projects

  1. Development of a Mid-femoral Orthotopic Model of Osteosarcoma in the Rat
  2. Effects of Adipose-Derived Mesenchymal Stromal Cells on Murine Osteosarcoma Pulmonary Metastasis and Local Recurrence
  3. Effect of Mesenchymal Stromal Cells (MSCs) on Host Immune Response to Cortical Allografts


Selected Funded Projects
(Research Support in the last 5 years.)

Kensey Nash, Inc. (Role: Principle Investigator)
Title: Bioglass/Ceramic Implants for the Healing of Critical Sized Calvarial Defects
Dates of Award: 2011-2014 $120,000

Musculoskeletal Transplant Foundation (Role: Co-Principle Investigator)
Title: Smart Allografts for Massive Bone Defects
Dates of Award: 2012-2015 $300,000

BioD, Inc. (Role: Principle Investigator)
Title: Amnion Derived Stem Cells for the Treatment of Osteomyelitis
Dates of Award: 2012-2014 $86,000

Allosource, Inc. (Role: Principle Investigator)
Title: Fate of Adipose Derived Stem Cells in a Critical Sized Femur Defect
Dates of Award 2012-2014 $86,000

Bio D, Inc. (Role: Principle Investigator)
Title: Efficacy of Amnion Derived MSCs in a Critical Sized Bone Defect
Dates of Award: 2012-2014 $153,000

Pfizer, Inc. (Role: Co-Investigator)
Title: Pulse Toceranib plus Lomustine for the Treatment of Unresectable Canine Mast Cell Tumors
Dates of Award: 2010-2012, $90,544

Allosource, Inc. (Role: Principle Investigator)
Title: Efficacy of a Novel Cell Based Therapy on a Critical Sized Defect
Dates of Award: 2011-2012, $44,654

Allosource, Inc. (Role: Principle Investigator)
Title: Stem Cell Fate Following Implantation in a Critical Sized Defect
Dates of Award: 2011-2012, $38,975

BioD, Inc. (Role: Principle Investigator)
Title: Amnion-Derived Stromal Stem Cells and Bone Healing
Dates of Award 2011-2012, $28.354

Musculoskeletal Transplant Foundation (Role: Principle Investigator)
Title: Effect of Systemically Injected Stem Cells on Massive Allograft Incorporation
Dates of Award: 2010-2011, $130,000

NIH SBIR 1 R43 CA119840-01 (Role: Co-Investigator)
Title: Provoking Anti-tumor Immune Response with FAS Ligand In Osteosarcoma
Dates of Award: 2006-2011, $202,000

Algeta, Norway (Role: Co-Investigator)
Title: Long Term Radiotoxicity Study of Repeat Dose Intravenous Radium-223 in Normal Dogs
Dates of Award: 2008-2009, $367,000

RZN, Neutraceuticals, Inc. (Role: Co-Principle Investigator)
Title: Randomized, Placebo-Controlled Clinical Trial of the Efficacy of an Herbal Supplement in the Treatment of Pain and Lameness in Dogs
Dates of Award: 2008-2010, $72,228

Algeta, Norway (Role: Principal Investigator)
Title: Biodistribution Study of Single Dose of Intravenous Radium-223 in Normal Dogs
Dates of Award: 2007-2009, $117,581

Kindy-French Foundation (Role: Co-Investigator)
Title: Bisphosphonate-Targeted Chemotherapy to Treat Osteosarcoma Pain
Dates of Award: 2008-2009, $54,909

Selected Publications
(Out of 51 published or in press.)

Ehrhart N. Longitudinal Bone Transport for Treatment of Primary Bone Tumors in Dogs: A Classification of the Technique an Summary of Nine Cases, Vet Surg. 2005 Jan-Feb;34(1):24-34.

Ehrhart N., Eurell JA, Constable PD, Ehrhart EJ, Johnson AL, Gaddy D, Nicholas RW. The effect of preoperative host tissue irradiation on large segment allograft incorporation. Clin Orthop Relat Res. 2005 Jun;(435):43-51.

Ehrhart N., Hong L, Eurell JA, Jamison R, Morgan A. The Effect of sustained release TGF-beta 1 on bone formation in a preoperatively irradiated critical-sized defect. J Am Vet Res. 2005 Jun; 66 (6): 929-1104.

Jehn CT, Farese JP, Lewis DD, Kuntz C, Ehrhart N. Canine Osteosarcoma. Veterinary Medicine. 2005 April; 100 (4):295-307.

Dennis MM, Ehrhart N., Duncan CG, Barnes AB, Ehrhart EJ. Frequency of and risk factors associated with lingual lesions in dogs: 1,196 cases (1995-2004). J Am Vet Med Assoc. 2006 May 15;228(10):1533-7.

Jehn CT, Lewis DD, Farese JP, Ferrell E, Conley W, Ehrhart N. Transverse bone transport osteogenesis: A morphologic comparison of two techniques for limb salvage in dogs. Vet Surg. 2007 36:324-334.

Liptak JM, Ehrhart N., Santoni BG, Wheeler DL. Cortical bone graft and endoprosthesis in the distal radius of dogs: a biomechanical comparison of two different limb-sparing techniques. Vet Surg. 2006, 35(2):150-60.

Liptak JM, Dernell WS, Ehrhart N., Lafferty M, Monteith GJ, Withrow SJ. Cortical allograft and endoprosthesis for limb-sparing surgery in dogs with distal radial osteosarcoma: a prospective clinical comparison of two different limb-sparing techniques. Vet Surg. 2006 Aug;35(6):518-33.

Modiano JF, Breen M, Lana SE, Ehrhart N., Fosmire SP, Thomas R, Jubala CM, Lamerato-Kozicki AR, Ehrhart EJ, Schaack J, Duke RC, Cutter GC, Bellgrau D, Flint MG. Naturally occurring translational models for development of cancer gene therapy. Gene Ther Mol Biol. Vol 01/2006; 10(10):31-40.

Bacon NJ, Dernell WS, Ehrhart N., Powers BE, Withrow SJ. Evaluation of primary re-excision after recent inadequate resection of soft tissue sarcomas in dogs: 41 cases (1999-2004) J Am Vet Med Assoc. 2007 Feb 15;230(4):548-54.

Bacon NJ, Ehrhart N., Dernell WS, Lafferty M, Withrow SJ. Use of alternating administration of carboplatin and doxorubicin in dogs with microscopic metastases after amputation for appendicular osteosarcoma: 50 cases (1999-2006). Am Vet Med Assoc. 2008 May 15;232(10):1504-10.

Santoni BG, Turner AS, Wheeler DL, Nicholas RW, Anchordoquy TJ, Ehrhart N. Gene therapy to enhance large segment allograft healing. Clin Orthop Relat Res. 2008 Aug;466(8):1921-9.

B Santoni, Ehrhart N., AS Turner, D Wheeler. Effects of low energy pulsed ultrasound with and without increased porosity on structural bone allograft incorporation. J Orthop Surg Res. 2008 May 27; 3:20.

Ehrhart N., Kraft S, Conover D, Rosier RN, Schwarz EM. Quantification of massive allograft healing with dynamic contrast enhanced-MRI and cone beam-CT: a pilot study. Clin Orthop Relat Res. 2008 Aug;466(8):1897-904.

Ryan S, Ehrhart N., Zuelsdorff K, James S. Comparison of alternate and simultaneous tensioning of wires in a single ring construct. Vet Surg. 2009 Jan;38(1):96-103.

Santoni BS, Ehrhart N., Betancourt-Benitez R, Beck CA, Schwarz EM. Quantifying Massive Allograft Healing of the Canine Femur in vivo and ex vivo. Clinical Orthopedics and Related Research. Clin Orthop Relat Res. 2012 Sep;470(9):2478-87.

Modiano JF, Bellgrau B, Cutter GR, Lana SE, Ehrhart N., Ehrhart EJ, Wilke VL, Charles JB, Munson S, Scott MC, Pozniak J, Carlson CS, Schaack J, Duke RC. Inflammation, Apoptosis, and Necrosis Induced by Neoadjuvant Fas Ligand Gene Therapy Improves Survival of Dogs With Spontaneous Bone Cancer. Mol Ther. 2012 Dec; 20(12):2234-43.

Almodóvar J, Mower J, Banerjee A, Sarkar AK, Ehrhart N., Kipper MJ. Chitosan-heparin polyelectrolyte multilayers on cortical bone: periosteum-mimetic, cytophilic, antibacterial coatings. Biotechnol Bioeng. 2013 Feb;110(2):609-18.

Santoni BG, Ehrhart N., Betancourt-Benitez R, Beck CA, Schwarz EM. Quantifying massive allograft healing of the canine femur in vivo and ex vivo: a pilot study. Clin Orthop Relat Res. 2012 Sep;470(9):2478-87.

Schwartz AL, Custis JT, Harmon JF, Powers BE, Chubb LS, LaRue SM, Ehrhart N., Ryan SD. Orthotopic model of canine osteosarcoma in athymic rats for evaluation of stereotactic radiotherapy. Am J Vet Res. 2013 Mar;74(3):452-8.

Culp WT, Ehrhart N., Withrow SJ, Rebhun RB, Boston S, Buracco P, Reiter AM, Schallberger SP, Aldridge CF, Kent MS, Mayhew PD, Brown DC. Results of surgical excision and evaluation of factors associated with survival time in dogs with lingual neoplasia: 97 cases (1995-2008). J Am Vet Med Assoc. 2013 May 15;242(10):1392-7.

Ehrhart N., Kaminskaya K, Miller JA, Zaruby JF. In vivo assessment of absorbable knotless barbed suture for single layer gastrotomy and enterotomy closure. Vet Surg. 2013 Feb;42(2):210-6.

Post Doctorates/Graduate Students:
Bill Culp, DVM, MS, Post Doctoral Studies

Anthony Schwartz, Ph.D., Doctoral Studies

Kaitlyn McNamara, MS, Masters Studies

Megan Aanstoos-Ewen, Ph.D., MS, Doctoral Studies

Ruth Rose, DVM, DACVS, Post Doctoral Studies


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