Where do the Bone Marrow Stem Cells come from ?
Bone marrow is very closely connected to the blood circulation through special sinusoidal capillaries in the center of large bones such as the hip bone. These capillaries allow the BMSC to move in and out of circulation readily. During the BMSC aspiration procedure, hundreds of millions of cells are aspirated with the bone marrow and placed through a class 2 medical device, cleared by the Food & Drug Administration (FDA), which separates the total nucleated fraction. This fraction is then used for local injections for the eyes, intranasal placement, paraspinal placement and intravenous placement depending on the tissue to be treated. Our procedure uses a board certified orthopedic surgeon who aspirates the BMSC from the posterior iliac crest or hip bone.
How do intravenous bone marrow stem cells get to damaged tissue?
When stem cells are injected directly into the area to be treated, they remain in that area at least for a period of time. If they are injected intravenously, they first go to the right side of the heart, they through the capillaries in the lungs, then back to the left side of the heart and then out the arterial circulation to the capillaries in the tissues. BMSC go through the lungs 30 x better than any other type of stem cells- therefore they can get to the capillary beds in the tissues.
What are some of the mechanisms by which BMSC provide benefit?
There have been a number of mechanisms identified for the effects of BMSC including MSC-derived exosomes providing microRNA, presence of growth factors including brain- derived neurotrophic growth factor (BDNF),nerve growth factor (NGF), glial cell line-derived neurotrophic factor (GDNF), paracrine effects as well as transdifferentiation of the stem cells. Previous work has identified ascendant and descendent axons in regenerated nervous tissue following intralesional spinal cord administration of BMSC in a murine model. Intravitreal bone marrow derived stem cells as provided in SCOTS were identified as CD34+ (BMSC) and could be seen transdifferentiating into NeuN- positive neuronal cells. NeuN is a neuron specific nuclear protein considered a marker for neurons of the central and peripheral nervous system. BMSC promoted neurite outgrowth through neurotrophic factors in vitro including BDNF, NGF and GDNF. Our opinion is that, depending on the disease mechanisms, one or more of these methods may predominate and provide a beneficial outcome in various retinal and optic nerve disease.