What are Mesenchymal Stem Cells?

What does Mesenchymal Mean?

The root word mesenchymal refers to a certain class of development and anatomy. It states a histological connection a cell type or tissue has with the mesoderm one of the main germ layers of the embryo.

Mesoderm is a part of the developing embryo which forms many of the connective tissues in the body such as bone, cartilage, muscles, and connective tissues. The mesenchymal relationship for cells is used to denote those formed from mesoderm or those which act as supportive tissue in relation to these structures.

What characteristics define Mesenchymal stem cells?

There is a set of MSC characteristics which researchers commonly use in order to describe them. These are the accepted MSC definitions for describing populations of the cells and studying them:

1. The ability of these types of stem cells to adhere to plastic surfaces under standard culture conditions.

2. The presence of CD105, CD73, and CD90, which are cell surface markers characteristic of MSCs.

3. The ability under certain culture conditions to differentiate toward cells characteristic of bone, fat, and cartilage.

MSCs are a part of the wider category of somatic or adult stem cells. There are other characteristics of MSCs which researchers are still determining. Furthermore MSCs should always be considered to potentially vary based on source, isolation and culture conditions, and other parameters.

Differentiation of Mesenchymal stem cells

The defining characteristic of MSCs is the variety of cell types which they are able to differentiate into under the right conditions.

MSCs can be induced in culture conditions to transform into cells characteristic of:

• Bone

• Cartilage

• Fat

• Muscle

• Connective tissue

There is still a variety of cells MSCs have been able to be induced to display similarity to in laboratory experiments. However the ability of MSCs to differentiate, transform, and change is reliant on the source and initial preparation of the cells as well as the laboratory conditions and surrounding cells.

Note that scientists define the process of differentiation and turning into other types of specialized cells as a form of adaptation not transformation. The cells keep their core identity but adopt new properties with the change.

What is differentiation potential?

Differentiation is a term describing the transformation of a less specialized cell into a more specialized cell. This specialization is called cellular differentiation. In research it is common to encourage cells to differentiate through exposing them to certain laboratory conditions and inducing changes using hormones growth factors and other methods.

Genes play a significant role in regulating the type of differentiation and the activity of cells histone modification and DNA methylation can affect this. Differentiation will have several stages and it depends on the type of the cell and what change is desired what all the precise mechanisms and steps involved are.

What is the function of Mesenchymal stem cells?

MSCs have several potential uses which are currently being discovered by researchers in the field of regenerative medicine.

Differentiation potential

MSCs can be induced to transform into certain specific types of other cells under laboratory conditions – for instanc, bone-like, cartilage-like, fat-like cells and others. This quality has been studied extensively in research and has been instrumental in the development of current understanding MSCs properties.

Immunomodulatory properties

MSCs have been studied and their ability to modulate the immune system has been established. Scientists know that MSCs are capable of supporting functions carried out by healthy cells and are instrumental in fighting diseases and supporting bodily functions.

The properties of MSCs provide potential benefits. Specifically MSCs have been studied for their immunomodulatory effects and have shown possible efficacy for a variety of diseases and conditions.

Potential role in tissue repair

It has also been established that MSCs can support tissue repair and regeneration specifically through interacting with neighboring cells and delivering exosomes containing growth factors cytokines, hormones and other substances. Researchers are investigating the role which MSCs play in repair and healing, the formation of new blood vessels the body’s inflammatory response and other processes.

The ability of MSCs to aid repair processes has been shown to be very important and beneficial. However it is equally crucial to remember that just because a particular MSC-based treatment performed well under the experimental or clinical laboratory conditions that does not automatically mean that a treatment using them will have similar benefits.

Where are Mesenchymal stem cells found?

MSCs or MSC-like cells have been studied in a variety of locations:

1. Bone Marrow: BMSCs have been one of the most common sources of MSC research. Cells can be harvested from the bone marrow using aspiration techniques.

2. Adipose Tissue: Fat contains stromal cells a type which also has mesenchymal properties.

3. Umbilical Cord Tissue: Cells associated with the umbilical cord have also been extensively studied in MSC research notably Wharton's Jelly.

4. Peripheral Blood: MSC like cells can be found in peripheral blood but at low levels.

5. Placental Tissue: The placenta also has been studied for its potential MSC sources.

6. Synovial Tissue and Fluid: Researchers have examined the possibilities presented by MSCs found in joints

7. Dental Pulp: Another potential rich source of mesenchymal stem cells.

The properties of MSCs vary for cells cultured in different parts of the body – due to different surrounding cells environmental influences and other factors.

The differences in isolation procedures for obtaining MSCs also can bring inconsistencies for MSC research.

What are the disadvantages of Mesenchymal stem cells?

While the research into MSCs is promising it is also very complicated. The field is in the process of discovering new information about it constantly. However as is the case with all areas of medicine there have also been complications encountered which researchers try to resolve.

1. Differences between cell sources

MSCs derived from different origins such as bone marrow and fat, umbilical cord and other sources have different characteristics. Thus the consistency in research results and findings is difficult to maintain. This can hamper the development of research further as scientists must be able to achieve consistent results before being able to build on top of the previous findings.

2. Variation in isolation and expansion

Variation in MSC research can also exist due to the use of different techniques across laboratories to isolate, expand, characterize and test the cells. All of these procedures influence both MSC properties and behavior and must be carefully controlled and standardized.

3. Variable differentiation potential

Furthermore the ability of MSCs to transform under culture conditions and display features of other types of cells is not constant and varies depending on the cell source, culture conditions, expansion parameters and environment.

4. Quality control

The ability for MSCs to consistently behave predictably and exhibit desired characteristics is highly important for continued clinical research.

5. Safety and efficacy

The fact that laboratory and clinical research into MSC use showed positive results does not automatically mean for all the diseases such treatments could potentially help. In reality it is highly likely that for each specific disease or patient group there is a certain optimal type of MSCs which would need to be administered in what quantity combined with which other methods are all questions needing to be answered.

Mesenchymal stem cells Vs. Hematopoietic stem cells

Mesenchymal stem cells and Hematopoietic stem cells (HSCs) are both types of stem cells however they belong to different categories.

Differentiation

MSCs have the capacity to differentiate into a number of cell types most frequently bone, cartilage, and fat.

HSCs are able to differentiate into all types of blood cells including the various types of white blood cells as well as platelets and red blood cells making them multipotent.

Sources

MSCs are able to be isolated from bone-marrow, fat, umbilical cord and other sources

HSCs can only be isolated from specific kinds of tissue such as bone marrow and blood.

Immune functions

MSCs are also known to have an impact on the activity of the immune system. On the other hand HSCs have the job of creating immune cells.

Medical research

MSCs are under investigation for their potential to treat a variety of diseases and medical conditions. Hematopoietic stem cell transplants have been used to treat a variety of blood cancers and disorders including leukemia and lymphoma.

MSC research has also been showing potential however there is still much that needs to be discovered and studied before any clinical application of these cells can take place.

What medical conditions are Mesenchymal stem cells being studied for?

There is a wide variety of medical conditions for which MSCs are being investigated. Examples of this research include the following:

1. Osteoarthritis

2. Rheumatoid arthritis

3. Graft-Versus-Host-Disease

4. Heart disease

5. Spinal cord injury

6. Autoimmune diseases

7. Type 1 diabetes

8. Lung diseases

9. Multiple sclerosis

10. Lyme disease

11. Parkinson's disease

12. ALS

There are a variety of reasons for which MSCs are being investigated for these conditions. Each study is in a different stage of research and each individual study must be evaluated carefully to see what exactly its results signify.

Mesenchymal stem cells and Regenerative Medicine

MSCs are an exciting frontier in the field of regenerative medicine primarily due to their differentiating potential, immunomodulatory properties, and interactions with surrounding cells.

At the same time research into MSC potential must be evaluated with care. Remember that the properties of the cells the procedure used to isolate them the place of their origin the specific treatment regimen used the dosage and the medical condition all play a role in determining the results.

Any specific MSC-based treatment should always be evaluated on a case basis. Furthermore always make sure that the specific type of treatment being used  whether it is a particular product or a specific procedure is authorized and being tested in appropriately designed clinical trials.

MSCs derived from a third-party donor are also discussed throughout this article including umbilical cord tissue. Patients researching these options can review donor-cell treatment options.