By now we have gained insight into the basics of Regenerative Medicine, such as where PRP and Stem Cells come from and their therapeutic applications for canine patients. It is generally understood that stem cells can be found in any tissue of the body. The two most common sources of stem cells for therapeutic applications are adipose tissue and bone marrow. A common misconception is that adipose derived stem cells provide a superior therapy versus bone marrow aspirate concentrate and that they are easier to collect and process. In this last segment of the Myth Buster Series, we will compare the two sources of stem cells, review their processing differences and determine if there really is a superior choice.
First, let’s consider how Adipose and Bone Marrow Derived Stem Cells are similar:
- They are both derived from the patient’s own body and are known as autologous adult-derived Mesenchymal stem cells
- Both can differentiate into cartilage, bone, tendon and ligament cell types.1
- They can treat certain similar indications with little to no clinical difference.2
- Both bone marrow and adipose derived stem cells can produce growth factors and anti-inflammatory proteins. These proteins have been shown to contribute to improved healing and reduced inflammation in injured tissues.3
- Both can be cultured to provide higher cell concentrations.
- There are commercially available systems to process either sample type.
- Collection of both Adipose tissue and Bone Marrow require anesthesia.
- Administration of either Adipose or Bone Marrow derived stem cells is typically done in combination with Platelet Rich Plasma.
- Fresh samples typically include a heterogenous mixture of several cell types.
Now let’s investigate how Adipose and Bone Marrow Derived Stem Cells are different:
♦ Time frame for processing
- Fresh Bone Marrow Aspirate Concentrate takes less than 30 minutes from collection to processing and can be done under one anesthetic episode.
- Fresh Adipose Derived Stem Cells take approximately 3-4 hours to process and require multiple anesthetic or sedative episodes.
♦ Processing requirements
- Fresh Bone Marrow Aspirate Concentrate involves collecting at least 25 mL of bone marrow from either the femur or humerus. It is then filtered and spun in a processing system for approximately 10 minutes. Once the spin is complete, the plasma is removed and 10% of total volume is collected.
- Fresh Adipose Derived Stem Cells involve taking approximately 20 grams of adipose under anesthesia, typically harvested from the falciform. The adipose is then mechanically and enzymatically disrupted to separate fat cells, blood cells and the Stromal Vascular Fraction.
- Stromal Vascular Fraction includes other cell types including white blood cells, fibroblasts, endothelial cells, hematopoietic stem cells and smooth muscle cells.
♦ Concentration of cells
- In a typical 25 mL collection of bone marrow aspirate, one can expect to have approximately 30,000 stem cells in 3 mL.
- A typical 20 gram collection of adipose (fresh) will yield 600,000 cells that are considered the Stromal Vascular Fraction.
- Please Note: There is little evidence in current research that suggests the ideal number of stem cells for treating certain conditions. In one such case, investigated in this peer reviewed paperby B. Carr, et. al., the small number of stem cells found in Bone Marrow Aspirate resulted in similar clinical effects compared to the higher concentration used from Adipose tissue. As our knowledge continues to evolve surrounding indications and specific protocols, these numbers may vary depending on what is being treated.
♦ Open vs. Closed System
- With Bone Marrow Aspiration, commercially available in-house systems are fully enclosed since the cells are collected via syringe and placed directly into concentrating devices.
- For Adipose processing, conical tubes are used for adipose digestion and processing, which is classified as an “open system”. This generally means that the samples are exposed to the outside environment which may affect the contents that are being processed. In academic and industry research facilities, it is typically recommended that samples processed utilizing open containers be placed in a fume hood to limit exposure to the surrounding environment.
♦ Equipment Necessary to Process Samples
- Processing Bone Marrow Concentrate requires a specialized centrifuge designed for concentration of the aspirate. Commercially available kits typically provide syringes, bone marrow collection needles, anticoagulant and concentrating devices.
- Processing Adipose Tissue requires a specialized centrifuge along with additional equipment including incubator water bath and agitator. Commercially available kits also provide syringes, anticoagulant, enzymes and concentrating devices/ processing tubes.
AND THE WINNER IS………………………Well, there really isn’t a winner or a loser in this case. Both Adipose and Bone Marrow Derived Stem Cells can be collected, processed and administered in the same day. Granted, there are differences in the processing times, cell concentrations and collection techniques, however, both therapies provide clinically effective results for similar indications. Deciding which tissue to collect stem cells from is dependent on personal preferences and training. There are numerous educational courses that provide hands-on instruction for either collection technique. If you are interested in learning bone marrow collection and processing, check out one of our upcoming Companion Regenerative University courses. The most important question to ask is “What is my goal for providing this therapy?”. If you answer that question, you may come out with your own Adipose vs. Bone Marrow Derived Stem Cell winner.
Stay tuned for our next blog which will investigate the role of White Blood Cells and their inclusion or exclusion in Platelet Rich Plasma!
References:
- The comparison of multilineage differentiation of bone marrow and adipose-derived mesenchymal stem cells. Xishan Zhu, Jing Du, Gang Liu. Clin Lab. 2012; 58(9-10): 897–903.
- Partial Cranial Cruciate Ligament Tears Treated with Stem Cell and Platelet-Rich Plasma Combination Therapy in 36 Dogs: A Retrospective Study. Canapp S.O. Jr, Leasure C.S., Cox K., Ibrahim V. and Carr B.J. (2016) Front. Vet. Sci. 3:112. doi: 10.3389/fvets.2016.00112
- Y.-M. Pers, M. Ruiz, D. Noël, C. Jorgensen, Mesenchymal stem cells for the management of inflammation in osteoarthritis: state of the art and perspectives, Osteoarthritis and Cartilage, Volume 23, Issue 11, November 2015, Pages 2027-2035, ISSN 1063-4584, http://dx.doi.org/10.1016/j.joca.2015.07.004.