1. Department of Surgery–Transplant & Mary & Dick Holland Regenerative Medicine Program, University of Nebraska Medical Center, Omaha, NE 68198, USA
2. Department of Anorectal Surgery, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, China
3. Departments of Surgery & Genetics, Cell Biology & Anatomy, University of Nebraska Medical Center, Omaha, NE 68198, USA
4. Department of Surgery, VA Nebraska–Western Iowa Health Care System, Omaha, NE 68105, USA
5. Department of Biochemistry & Biophysics & Linus Pauling Institute, Oregon State University, Corvallis, OR 97331, USA
6. Departments of Surgery–Plastic & Reconstructive Surgery, University of Nebraska Medical Center, Omaha, NE 68198, USA