PHYSIOLOGY 344
REGENERATIVE MEDICINE AND STEM CELLS
,WEEK 1: LECTURE 1
Regenerative Medicine and Stem Cells
Regenerative medicine is a branch of translational research in tissue/cell engineering and
molecular biology. It deals with the process of replacing, engineering, or regenerating
human cells, tissues, or organs to restore or establish normal function.
This field holds the promise of engineering damaged tissues and organs by stimulating the
body’s own repair mechanisms to functionally heal previously irreparable tissues or
organs.
Translational medicine is an interdisciplinary branch of the biomedical field supported by
3 main pillars:
1. Bench side
2. Bed side
3. Community
Regenerative medicine also includes the possibility of growing tissues and organs in the
laboratory, and thereafter implanting them into the human body, when it is unable to
heal and repair itself.
If the cells of a regenerated organ can be derived from the patient’s own tissue or cells,
this could potentially resolve the issues posed by availability of organs for donation and
other problems caused by transplant organ rejection.
Anti-aging medicine and cell therapy also form part of the regenerative medicine
industry, which is a billion-dollar industry.
The objective of cell therapy is to restore the lost function of tissues, rather than to
produce an entirely new organ.
Methods of Anti-Aging Therapy
1. Hyaluronic acid (such as fillers in the face)
2. Platelet rich plasma (patient’s own blood is used and spun in a centrifuge until the
plasma can be collected from the top of the sample and injected back into the
skin to regenerate skin cells)
3. Hormone therapies (mainly oestrogen)
4. Diet and supplements
5. Convalescent plasma and Covid-19
Hyaluronic Acid Therapy
Hyaluronic acid is a naturally occurring, linear polysaccharide composed of repeating
disaccharide units, such as D-glucuronic acid and N-acetyl-D-glucosamine, linked by β-
1,3 and β-1,4 glycosidic bonds. It is a primary component of the extracellular matrix of the
skin and it is also an important structural element in the skin.
Hyaluronic acid is present in high concentrations in the following locations:
, • Synovial joint fluids
• Vitreous humour of the eyes
• Hyaline cartilage
• Intervertebral disc nucleus pulposus
• Umbilical cord
• Connective tissues
Hyaluronic acid holds water extremely well, and has the following uses:
1. Supplementation of impaired synovial fluid in arthritic patients, whereby it is
injected, using a needle, into the synovial joints
2. Aesthetic medicine as dermal fillers
3. Soft tissue surgeries such as vocal fold augmentation
4. Scaffolding for tissue regeneration applications
5. Hydrogels used in wound repair and soft tissue regeneration during surgery
In terms of wound healing, tissue repair and tissue regeneration, a wound matrix that is
high in hyaluronic acid facilitates cell motility and proliferation. Both of these are
processes that are essential for wound repair, and work in a manner similar to that of a
hydrogel.
While the intact hyaluronic acid maintains the tissue in a hydrated state, degraded
hyaluronic acid released into the wound is able to promote cell proliferation, cell
migration and angiogenesis.
Finally, hyaluronic acid facilitates scarless wound healing processes, and the essential role
that it plays in wound healing justifies its utilization in tissue repair and regeneration, for
example, in the treatment of burn wounds.
WEEK 1: LECTURE 2
Platelet Rich Plasma
The vampire procedure is a procedure whereby plasma and platelets from the patient’s
own blood is used to regenerate the skin. This procedure can be impaired if the patient
has systemic inflammation or is a smoker. This is because during systemic inflammation,
inflammatory biomarkers such as cytokines are present in circulation. Consequently,
inserting that patient’s own plasma and platelets into the
skin would also insert inflammatory molecules into the
skin.
Hormone Therapy
Hormone therapy is identified as bioidentical hormone
replacement therapy, and examples include the
contraceptive pill, or oestrogen replacement therapy.
Oestrogen replacement therapy may be extremely
beneficial under certain circumstances, however, under
instances where the patient is prone to stroke or heart
, attacks, the hormone replacement therapy can cause the blood of the patient to
become stickier, thus causing hypercoagulation. This abnormal clotting can then result in
a stroke or a heart attack.
A thrombo-embolic stroke occurs when there is an instance of hypercoagulation, and
therefore is as a result of abnormal clotting. A haemorrhagic stroke occurs as a result of
hypertension causing a small blood vessel in the brain to burst.
Oestrogen can have a negative influence on red blood cells, and therefore the
haematological system. When oestrogen is present in high levels in the blood, red blood
cells can undergo visible changes. This is because oestrogen causes the cell membrane
of red blood cells to become more flexible, and this flexibility does not allow the cell to
revert to its original structure when it travels through the narrow capillaries. Membrane
damaged red blood cells are unable to carry oxygen efficiently.
Naturally, soluble fibrinogen is converted into insoluble fibrin fibres to form an intricate
meshwork structure. When oestrogen is present, this network becomes a thickened,
matted deposit, which is the cause of heart attacks and strokes.
Oestrogen can also cause platelets to become hyperactivated. In this case, one would
not see the normal round structure of the platelets, but rather when activated, platelets
possess feet-like processes called pseudopodia. When it comes to activating platelets,
oestrogen has its place, however it can be detrimental as well. A female using hormone-
based contraceptives or hormone replacement therapies should be careful since
oestrogen has the ability to negatively influence platelets, red blood cells, and blood
clotting processes.
Convalescent Plasma
Convalescent plasma therapy, also known as hyperimmune immunoglobulin, is an
experimental treatment that some doctors are using for people with severe COVID-19
symptoms.
No drug has been proven to be safe and effective for treating COVID-19. The U.S. Food
and Drug Administration (FDA) has not approved any drugs specifically to treat COVID-19.
People who have recovered from COVID-19, however, have antibodies in their blood.
Antibodies are proteins that the body uses to fight off infections. The blood of people who
have recovered is called convalescent plasma. Plasma is the liquid portion of the blood.
