Basic Types of Stem Cells

There are two basic styles of stem cells: Fetal/Embryonic stem cells and Adult Stem Cells. Within these types of stem cells, there are sub-categories depending on the timing and location of harvest.

Embryonic Stem Cells

These stem cells have the ability to divide indefinitely and become any type of cell in the body (pluripotent), therefore researchers saw them as a panacea for the treatment of many diseases. The reality is that they are notoriously difficult to control and tend to form tumors. Aside from the well-known ethical debate, there has not been a successful clinical trial using embryonic stem cells to date.

Neural rosettes, derived from human embryonic stem cells, assemble into spheres in culture. Credit: Gist Croft / Ali Brivanlou / Rockefeller University.

Fetal Stem Cells

Fetal stem cells are harvested from aborted fetuses. Few researchers are willing to work with fetal stem cells due to ethical concerns. Recently, Geron started a clinical trial treating spinal cord injury with fetal stem cells but that trial was halted. Like embryonic stem cells, fetal stem cells have been known to cause tumors in human subjects.

Mouse embryonic stem cells. Credit: Kitkai Kim Lab /Sloan Kettering Institute

Amniotic Stem Cells

There are many bioactive molecules that are the building blocks for tissue regeneration and immunomodulatory mechanisms in the secretions released by amniotic fluid-derived and amniotic tissue-derived mensencymal stem cells (MSCs).These bioactive molecules include: interleukins, growth factors, interferons, cell adhesion molecules, and glycosaminoglycans.MSCs have been shown to work in an immunomodulatory capacity andhave been transplanted into animals without inducing any tumorigenic effects.

scientific american: a new source of stem cells

Recovered amniotic tissue.

Perinatal Stem Cells

There are two main types of umbilical cord stem cells:

  • Mesenchymal stem cells from human umbilical cord tissue (hUCT-MSCs)
  • Hematopoietic stem cells from human umbilical cord blood (hUCB-HSCs)

hUCB-HSCs, (CD34+ stem cells) form blood cells and are the only type of stem cell approved by the US FDA to treat several rare blood disorders. There are ongoing clinical trials using hUCB-HSCs to treat various diseases and conditions, most notably at Duke University for cerebral palsy and autism.

hUCT-MSCs  work by secreting bioactive molecules called trophic factors, not by differentiating into new cell types. They:

  1. Control inflammation
  2. Modulate the immune system
  3. Stimulate regeneration
  4. Reduce scarring

hUCT-MSCs are different than other types of stem cells because they are immunologically immature. In other words, they are not antigenic, so they are tolerated by the patient’s immune system and do not require immune-suppressive drugs as part of treatment. They are also non-tumorigenic because they are not differentiating into new cells types in the patient.

hUCT-MSCs are used to treat a variety of  conditions at the Stem Cell Institute in Panama including:  autism, cerebral palsy, heart failure, multiple sclerosis, osteoarthritis, rheumatoid arthritis, spinal cord injury, and other autoimmune disorders.

A single human MSC in suspension, taken at Medistem Panama

“Golden Cells” at Stem Cell Institute in Panama

Through retrospective analysis of our cases, we’ve identified proteins and genes that allow us to screen several hundred umbilical cord donations to find the ones that we know are most effective. We only use these cells and we call them ‘golden cells’.

We go through a very high throughput screening process to find cells that we know have the best anti-inflammatory activity, the best immune modulating capacity, and the best ability to stimulate regeneration.

It is important to note that hUCT-MSCs  that were isolated and grown in our laboratory in Panama to create master cell banks are currently being used in the United States.

These cells serve as the starting material for cellular products used in MSC clinical trials for two Duchenne’s muscular dystrophy patients under US FDA’s designation of Investigational New Drug (IND) for single patient compassionate use. (IND 16026 DMD Single Patient) – Dr. Riordan

For more information about stem cell therapy with hUCT-MSCs in Panama, please read Dr. Riordan’s book: Stem Cell Therapy: A Rising Tide – How Stem Cells Are Disrupting Medicine and Transforming Lives

Non-Perinatal adult stem cells

Adult stem cells (ASCs) are cells that come from a live human, regardless of age. Stem cells harvested from a young child’s bone marrow are still “adult” stem cells. As previously stated, postnatal stem cells harvested from human umbilical cord tissue or blood after live births are also classified as adult stem cells.

Adult stem cells are found throughout the body in many organs and tissues. However, the major two sources for adult stem cells used in most treatments in the United States are harvested from adipose tissue (fat) and bone marrow.

A picture of human MSCs dividing, taken at Medistem Panama.

Adipose (fat) stem cells

In humans, mesenchymal stem cells (MSCs) exist in many tissues as a dormant cell form known as a pericyte (peri means “around” and cyte means “cell”). Pericytes hold tight to capillaries, the smallest of blood vessels that exist throughout the body at the ends or arteries. When the body senses an injury or inflammation, some pericytes are recruited to help heal tissues, at which point they become activated MSCs.

Human fat is a particularly abundant source of MSCs (Ad-MSCs). Ad-MSCs work in a similar manner to hUCT-MSCs (described above). However, very few clinics or trials use purified Ad-MSCs.  Most use Stromal Vascular Fraction (SVF), which is made by digesting fat with enzymes and spinning it in a centrifuge.  SVF can contain large numbers of Ad-MSCs along with several other types of cells.

Stem Cell Institute pioneered treating patients with osteoarthritis, rheumatoid arthritis, multiple sclerosis, and other autoimmune diseases using fat-derived stem cells. However, they no longer use a patient’s own stem cells from fat because experience over time has shown that mesenchymal stem cells from umbilical cord tissue perform better. hUCT-MSCs have also been shown to modulate the immune system and control inflammation more effectively. hUCT-MSCs also proliferate much more efficiently than Ad-MSCs, especially Ad-MSCs harvested from older donors, or those with compromised autoimmune systems like MS patients.

Dr. Riordan published the first scientific article on treating humans (Three multiple sclerosis patients) with SVF: Non-expanded adipose stromal vascular fraction cell therapy for multiple sclerosis.  

Plated human MSCs derived from adipose tissue.

Bone Marrow Stem Cells

Bone marrow contains both MSCs and CD34+ stem cells, and endothelial precursor cells (EPCs), along with a many other types of cells including lymphocytes and monocytes, which are types of white blood cells.  

Bone marrow contains a high concentration of CD34+ cells, which as explained above are blood-forming stem cells.  Compared to umbilical cord tissue and fat, bone marrow contains a very low concentration of MSCs. Bone marrow is rich in EPCs, which are known to stimulate blood vessel growth.

Both MSCs and CD34+ cells can be isolated from bone marrow and expanded into greater numbers in a lab. However, most treatments performed today simply process the bone marrow in a centrifuge and inject the portion of the concentrate containing the MSCs, CD34+ cells, and white blood cells. This product is commonly referred to as bone marrow aspirate concentrate (BMAC). In addition to MSCs and CD34+ cells, BMAC also contains growth factors that are capable of stimulating cellular growth, proliferation, healing and differentiation (changing into another type of cell such as a blood vessel cell).

Often a centrifuge is used to spin the bone marrow to isolate the concentrate, called bone marrow aspirate concentrate (BMAC).

Along with hUCT-MSCs administered both intravenously (IV) and intrathecally (IT), the spinal cord injury protocol at SCI also incorporates cells from the patient’s own concentrated bone marrow.

Several studies have shown that cells concentrated from the patient’s own bone marrow as sole therapy can improve the functionality of spinal cord injury patients. The main reason for adding bone marrow is primarily for its ability to stimulate new blood vessel growth. Most spinal cord injuries are traumatic and lead to a loss of blood flow to the spinal cord area, which has very few blood vessels in the first place, compared to other tissues and organs.  Creation of new blood vessels with these cells is very important to stimulate healing.

BMAC can be highly effective for bone, muscle, tendon, ligament, and cartilage injuries.  That is why doctors at RMI use BMAC to treat a wide variety of acute and chronic orthopedic conditions of the knee, hip, spine, shoulder, elbow, ankle, foot, wrist, and hand.   

At RMI, BMAC can be injected non-surgically into the joint space, or directly into an affected ligament, tendon, muscle, disc, or other area using precise ultrasound and fluoroscopic C-Arm guidance. BMAC is also used to augment minimally invasive orthopedic surgical procedures in order to facilitate faster healing and reduce complications.

BMAC injections at RMI are usually augmented with injections of an amniotic tissue product. This product adds over 100 different growth factors, many of which are not present in bone marrow. Two of the most important are prostaglandin and WNT-4. Prostaglandin inhibits inflammation, which occurs after injury and marks the beginning of the healing process. The faster we can tame this inflammation, the sooner the body can move on to the next phase of healing, regeneration. WNT4 is arguably the single most important molecule required for wound healing.

Along with hUCT-MSCs administered both intravenously (IV) and intrathecally (IT), the spinal cord injury protocol at SCI also incorporates cells from the patient’s own concentrated bone marrow.

Several studies have shown that cells concentrated from the patient’s own bone marrow as sole therapy can improve the functionality of spinal cord injury patients. The main reason for adding bone marrow is primarily for its ability to stimulate new blood vessel growth. Most spinal cord injuries are traumatic and lead to a loss of blood flow to the spinal cord area, which has very few blood vessels in the first place, compared to other tissues and organs.  Creation of new blood vessels with these cells is very important to stimulate healing.

BMAC can be highly effective for bone, muscle, tendon, ligament, and cartilage injuries.  That is why doctors at RMI use BMAC to treat a wide variety of acute and chronic orthopedic conditions of the knee, hip, spine, shoulder, elbow, ankle, foot, wrist, and hand.   

At RMI, BMAC can be injected non-surgically into the joint space, or directly into an affected ligament, tendon, muscle, disc, or other area using precise ultrasound and fluoroscopic C-Arm guidance. BMAC is also used to augment minimally invasive orthopedic surgical procedures in order to facilitate faster healing and reduce complications.

BMAC injections at RMI are usually augmented with injections of an amniotic tissue product. This product adds over 100 different growth factors, many of which are not present in bone marrow. Two of the most important are prostaglandin and WNT-4. Prostaglandin inhibits inflammation, which occurs after injury and marks the beginning of the healing process. The faster we can tame this inflammation, the sooner the body can move on to the next phase of healing, regeneration. WNT4 is arguably the single most important molecule required for wound healing.