Mesenchymal stem cell number required for tissue growth

How many mesenchymal stem cells are injected with each stem cell injection treatment?

First of all, I’d like you to remember, what is Prolotherapy? Prolotherapy is an injection treatment given to stimulate the body to repair injured areas. Prolotherapy using stem cells derived from bone marrow is another way to direct more healing growth factors directly to the injured areas. Mesenchymal stem cells (MSC) are fibroblast-like cells which are able to self-renew and differentiate into bone, adipose, meniscus, and cartilage tissue. They have been traditionally isolated from bone and that is the process done at Caring Medical when we desire to use stem cells for the Prolotherapy treatment.

We use what we call stem cell injection therapy, meaning that the bone marrow is extracted out of the patient’s bone (either the tibia or iliac crest) and then directly injected into the injured area(s). The actual number of mesenchymal stem cells (MSCs) in a specific sample of bone marrow will vary depending on the health of individual and of course the person’s age. Most references state that from 0.01% to 0.001% of cells in bone marrow are MSCs.1, 2, 3The number of nucleated cells in bone also can vary widely with ranges from 2 x 106 to 5 x 107 cells per milliliter. So you can do the math.

For example if someone received 5cc of direct bone marrow into the knee, this calculation may come out to the following:

1 x 107 cells/ml x 10ml/cc x 5cc = 5 x 108 cells with .001 to .001% being MSCs = 5 x 103 to 5 x 104 mesenchymal stem cells.

Remember this is all speculative because each person’s bone marrow is different.  Here we are also talking about mesenchymal stem cells, as this does not include other types of stem cells. If 20 of the stem cells “take” and start self-renewing or replicating, after six months of doubling every week, the total amount of stem cells in a person’s knee, for instance, in six months will be over 670,000,000 (670 million). Thus it does not take a lot of stem cells to be actively replicating, laying down healthy tissue for a joint to be repaired. That is the thought anyway.

If you start with 5 x 103 (5000) mesenchymal stem cells and they double every week, after 26 weeks you would have 335,544,320,000 (335 billion plus cells).

If you start with 5 x 104 (50000) mesenchymal stem cells and they double every week, after 26 weeks (6 months) you would have 3,335,443,200,000 (3 trillion plus cells.)

We are in the process of trying to find the best way to measure stem cell numbers contained in bone marrow aspirate. For now, we can just report on what others have found!

Proposed mechanisms of action with stem cell therapy:Realize, however, that the beneficial effects of Bone Marrow Prolotherapy or Stem Cell Prolotherapy may not come from the stem cells, but from growth factors and other bioactive substances in the bone marrow. It also may come from the growth factors or bioactive substances actuallysecreted from the stem cells. Most likely it is a combination of factors.

We do know the bone marrow contains chondroprogenitor cells. These are cells that help the cartilage repair. Some of these cells can turn into the chondrocytes that actually make the articular cartilage, but perhaps the injured knee also needs synovial cells that make the hyaluronic acid and other components of the joint fluid that gives nourishment to the cartilage. It is probable that when a patient receives direct bone marrow aspiration into an injured knee that many factors are involved in helping the knee to heal, including differentiation of stem cells into articular cartilage, synovial and other cells that are needed in the joint, as well as the stimulation via growth factors to stimulate the various cells to repair the structures that are injured.

Stem cell therapy IS Prolotherapy: Regardless of the mechanism of action, the whole process is Prolotherapy because the definition of Prolotherapy is the stimulation of injured musculoskeletal tissues, such as ligaments, tendons, cartilage, or meniscus tissue, to repair by the induced proliferation of cells. The only difference with Bone Marrow Prolotherapy is that lots of cells are injected directly into the injured area. Typically direct Bone Marrow Aspiration Prolotherapy is done every six to eight weeks.

1Caplan AL. Adult mesenchymal stem cells for tissue engineering versus regenerative medicine.  Journal of Cellular Physiology. 2007; 213:341-347.

2Wang Y, Johnsen HE, Mortensen S.  Changes in circulating mesenchymal stem cells, stem cell homing factor, and vascular growth factors in patients with acute ST elevation myocardial infarction treated with primary percutaneous coronary intervention.  Heart. 2006; 92:768-774.

3Yoo JU, Barthel TS, Nishimura K.  The chondrogenic potential of human bone-marrow-derived mesenchymal progenitor cells.  The Journal of Bone and Joint Surgery. 1993; 80:1745-1757.