Regenerative medicine

Editor-in-Chief: Robert G. Schwartz, M.D. [1], Piedmont Physical Medicine and Rehabilitation, P.A.;

Overview

Regenerative medicine is the "process of replacing or regenerating human cells, tissues or organs to restore or establish normal function".[1] This field holds the promise of regenerating damaged tissues and organs in the body by replacing damaged tissue and/or by stimulating the body's own repair mechanisms to heal previously irreparable tissues or organs. Regenerative medicine also empowers scientists to grow tissues and organs in the laboratory and safely implant them when the body cannot heal itself. Importantly, regenerative medicine has the potential to solve the problem of the shortage of organs available for donation compared to the number of patients that require life-saving organ transplantation. Depending on the source of cells, it can potentially solve the problem of organ transplant rejection if the organ's cells are derived from the patient's own tissue or cells.[2][3][4]

Widely attributed to having first been coined by William Haseltine (founder of Human Genome Sciences),[5] the term "Regenerative Medicine" was first found in a 1992 article on hospital administration by Leland Kaiser. Kaiser’s paper closes with a series of short paragraphs on future technologies that will impact hospitals. One such paragraph had ‘‘Regenerative Medicine’’ as a bold print title and went on to state, ‘‘A new branch of medicine will develop that attempts to change the course of chronic disease and in many instances will regenerate tired and failing organ systems.’’[6][7]

Regenerative Medicine refers to a group of biomedical approaches to clinical therapies that may involve the use of stem cells.[8] Examples include the injection of stem cells or progenitor cells (cell therapies); the induction of regeneration by biologically active molecules administered alone or as a secretion by infused cells (immunomodulation therapy); and transplantation of in vitro grown organs and tissues (Tissue engineering).[9][10]

A form of regenerative medicine that recently made it into clinical practice, is the use of heparan sulfate analogues on (chronic) wound healing. Heparan sulfate analogues replace degraded heparan sulfate at the wound site. They assist the damaged tissue to heal itself by repositioning growth factors and cytokines back into the damaged extracellular matrix.[11][12][13] For example, in abdominal wall reconstruction (like inguinal hernia repair), biologic meshes are being used with some success.

Clinical Indications

A few of the most common indications for regenerative medicine include joint space narrowing, other musculoskeletal applications, plastic surgery, and peripheral vascular disease. Orthopedic and musculoskeletal use predominate. Harvesting of adipose derived stem cells or bone marrow aspirate in combination with platelet rich plasma followed by implantation for joint space narrowing is growing in popularity among both the physician and lay communities. Commonly treated joints include knees, hips, shoulders and then elbows and ankles.

While stem cell therapy may be utilized, for conditions such as tendinopathy or ligamentous strain Platelet Rich Plasma alone offers an alternative to the more aggressive stem cell approach. The plastics community is also active in stem cell therapies for skin care, hair regeneration, and wound healing. Thereafter angiogenic applications for peripheral vascular disease have been gaining in popularity. Associated conditions include peripheral arterial disease, restless legs, ischemic neuropathy and wound healing.

Other indications exist as well but they are more rarely encountered in clinical practice. For example, interest in stem cell treatments for congestive heart failure, degenerative neurological disorders, and organ replacement has been expressed. Reports or organ replacement derived from stem cells are only now occasionally surfacing. Harvest and implantation sites are least developed for neurological conditions. While many hope that stem cell therapies hold great promise for a wide range of other conditions protocols for them are still under development.

References

1. Regenerative Medicine, 2008, 3(1), 1–5 [47]

2. "Regenerative Medicine. NIH Fact sheet 092106.doc" (PDF). September 2006. Retrieved 2010-08-16.

3. Mason C, Dunnill P (January 2008). "A brief definition of regenerative medicine". Regenerative Medicine 3 (1): 1–5. doi:10.2217/17460751.3.1.1. PMID 18154457.

4. "Regenerative medicine glossary". Regenerative Medicine 4 (4 Suppl): S1–88. July 2009. doi:10.2217/rme.09.s1. PMID 19604041.

5. http://www.nsf.gov/pubs/2004/nsf0450/ Viola, J., Lal, B., and Grad, O. The Emergence of Tissue Engineering as a Research Field. Arlington, VA: National Science Foundation, 2003.

6. Kaiser LR (1992). "The future of multihospital systems". Topics in Health Care Financing 18 (4): 32–45. PMID 1631884.

7. Lysaght MJ, Crager J (July 2009). "Origins". Tissue Engineering. Part a 15 (7): 1449–50. doi:10.1089/ten.tea.2007.0412. PMID 19327019.

8. Riazi AM, Kwon SY, Stanford WL (2009). "Stem cell sources for regenerative medicine". Methods in Molecular Biology 482: 55–90. doi:10.1007/978-1-59745-060-7_5. PMID

  19089350.

9. Stoick-Cooper CL, Moon RT, Weidinger G (June 2007). "Advances in signaling in vertebrate regeneration as a prelude to regenerative medicine". Genes & Development 21 (11): 1292–315. doi:10.1101/gad.1540507. PMID 17545465.

10. Muneoka K, Allan CH, Yang X, Lee J, Han M (December 2008). "Mammalian regeneration and regenerative medicine". Birth Defects Research. Part C, Embryo Today 84 (4): 265– 80. doi:10.1002/bdrc.20137. PMID 19067422.

11. a b c d Tong et al, Stimulated neovascularization, inflammation resolution and collagen maturation in healing rat cutaneous wounds by a heparan sulfate glycosaminoglycan mimetic, OTR4120. Wound Repair Regen. 2009 Nov-Dec;17(6):840-52.

12. a b c d Barritault et al, Regenerating agents (RGTAs): a new therapeutic approach. Ann Pharm Fr. 2006 Mar;64(2):135-44.

13. a b c d Van Neck et al, Heparan sulfate proteoglycan mimetics thrive tissue regeneration: an overview. In Intech book under the working title "Tissue Regeneration", ISBN 978-953-307-876-2 is scheduled for on line publication on Nov 26, 2011”