Stem Cells Laboratory

Adult Stem Cell Research

With current advances in science and technology, new fields of research and new questions arise. To stay current in research themes and provide information for effective decision making, the Centre for Vaccine Evaluation has a research program to examine the field of adult stem cell research.

 

What Are Adult Stem Cells and Embryonic Stem Cells?

Stem cells have two features that make them distinct from other cells. First, stem cells are capable of long-term self-renewal; that is, they are able to give rise to identical copies of themselves over and over again. Second, stem cells are defined by their unique ability to develop into different functional cell types. For example, stem cells in the brain can develop into all of the different cell types of the brain such as neurons, astroglia and oligodendrocytes, each of which has a separate function. Stem cells can be grouped into two broad categories: embryonic stem cells and adult stem cells (also known as somatic stem cells). The distinguishing properties of these cells are as follows:

  • Embryonic stem cells are derived from embryos at a specific stage in early development termed the blastocyst stage. Embryonic stem cells are capable of forming any cell type in the human body. They can be used to derive an entire organism, a property referred to as “pluripotency”.
  • Somatic or adult stem cells are found in fully developed organs and tissues. They can replace dying cells within their organ of residence and can repair minor tissue damage. Adult stem cells are usually restricted to forming only the type of cells found in their tissue of origin; however, some have demonstrated pluripotency.

The Centre for Vaccine Evaluation stem cell research program focuses only on adult stem cells. Because of the potential ethical issues surrounding the use of embryonic stem cells , it is likely that products derived from adult stem cells will be the first to be considered for widespread therapeutic use.

 

Why We Study Adult Stem Cells

Stem cells are the building blocks of all organs and tissues in the human body. As such, stem cells have been identified, in recent years, as having vast potential in medical applications. These cells can repair tissues by developing into specialized cell types such as nerve and muscle cells. Biologics derived from stem cells are currently being developed for treating ailments such as muscle injuries, neuronal disorders, loss of blood flow, heart disease, liver failure and cartilage deterioration. To evaluate these upcoming biologic products fully, a better understanding of the properties of human stem cells is needed in order to develop standardized tools for examining their safety and effectiveness.

 

How We Study Adult Stem Cells

At the Centre for Vaccine Evaluation, scientists want to develop new methods and models for testing the safety and efficacy of regenerative medicine products that are based on stem cells. The Centre's research team does this by growing adult stem cells in a culture medium in the laboratory and analysing them with sophisticated instruments. They identify characteristics of stem cells associated with therapeutic effectiveness. Examples of these characteristics include particular patterns of protein and gene expression. They examine these properties in the laboratory through the combined use of fluorescence microscopy, polymerase chain reaction (PCR), mass spectrometry (MS) and flow cytometric assays. This research will be important for:

  • Providing scientific information on how to evaluate therapeutic products that are based on adult stem cells;
  • Understanding the positive therapeutic potential of stems cells;
  • Understanding how to identify and address potential negative effects of stem cells;
  • Developing new assays to monitor the purity and safety of stem cell–based products;
  • Developing and applying models to evaluate how stem cells can be used to repair tissue and treat medical conditions;
  • Understanding and predicting adverse reactions arising from regenerative medicines that are based on stem cells.

 

Concepts and Tools We Use to Study Adult Stem Cells

The term “biomarker” is used to refer to something that may be an indicator for a specific biological substance, process or function. For example, specific DNA sequences can provide a genetic biomarker for the presence of cancer and may provide useful information for treating the disease. A biomarker may be a valuable tool to confirm the identity of a cell-based biotherapeutic product. For stem cell–based biologics, the expression of specific genes and the presence of certain proteins and enzymatic functions may serve as suitable biomarkers.

In the laboratory, work with flow cytometry involves using fluorescent chemicals to count and evaluate specific types of cells. Flow cytometers are equipped with lasers of different colours (wavelengths) and sets of detectors. These lasers and detectors simultaneously measure different characteristics of the cells and particles present in a fluid sample. The flow cytometer provides basic information on the physical characteristics of the cells such as size, granularity and DNA content. With this information, researchers can distinguish different types of cells within a sample.

The most common use of flow cytometry is to analyse the expression of proteins on the surface of cells. Researchers do this by using antibodies that interact specifically with a protein that they are investigating. Antibodies are coupled to fluorescent chemicals that will emit a specific colour of light when excited by the lasers on the flow cytometer. When antibody-treated samples are tested on the flow cytometer, all cells expressing the protein of interest on their surface will glow. The instrument detects, counts and measures the intensity of these glowing cells. Researchers use these data to identify a protein expression “signature” for cell types existing within a sample.

 

Research Highlight 1: Markers to Identify Mesenchymal Stem Cells

Mesenchymal stem cells (MSCs) are a type of adult stem cell that can develop into a variety of cell types including bone, cartilage, adipose or fat cells as well as skeletal muscle and neural tissue. As MSCs are naturally found in adult tissues, they can be isolated, and then grown in the laboratory to develop potential treatments for tissue damage and certain diseases. Therapeutic products based on MSCs are being developed but currently, there is no reliable method for identifying MSCs within the tissues where they reside.

At the Centre for Vaccine Evaluation, scientists investigate and characterize the various properties of MSCs in an effort to identify a biomarker that will consistently identify MSCs within different tissues. Using proteomics methods coupled with flow cytometry and functional stem cell assays, the research team aims to identify unique characteristics of MSCs and to provide adequate biomarkers of sample purity, safety and efficacy.

The Centre for Vaccine Evaluation is working to:

  • Understand the various properties and mechanisms of MSC growth that will provide insight into possible medical applications;
  • Characterize the properties of MSCs and provide guidance on how to evaluate the safety, efficacy and quality of therapeutic products that are based on stem cells;
  • Use a detection assay, based on markers of MSCs, to help develop standardized methods for demonstrating a product’s purity before it is used in therapeutic applications.

 

Research Highlight 2: Evaluation of a Pre-Clinical Model to Repair Tissue-Engineered Organ Cultures

Stem cells have the potential to help repair damaged tissues and organs.  The Centre for Vaccine Evaluation is interested in developing testing methods to evaluate the application of stem cells to repair tissue. For example, scientists are looking at different types of cell cultures that model complex tissues to determine whether these cell cultures have the potential to help evaluate stem cells and tissue repair.

The Centre for Vaccine Evaluation is working to:  

  • Develop assay systems that provide information to predict the therapeutic potential of stem cell-based products;
  • Provide increased understanding of the function of human stem cells within human tissue.

 

For information about the lead scientist of this laboratory, please visit their Directory of Scientists and Professionals profile.

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