Regenerative Medicine (PowerPoint)

Document Sample
Regenerative Medicine (PowerPoint) Powered By Docstoc
					      Regenerative Medicine
• Many treatments are not the
answer to curing the disease
• Regenerative medicine is
growing cells & tissues that can be
used to replace and/or repair
defective tissues & organs
• Goal: To improve the health
quality of life
• This area is focused on diseases
that affect systems with little or no
regenerative capacity, such as the
nervous system.
          Parkinson’s Disease
• Neurodegenerative disorders
(such as Alzheimer’s & Parkinson’s) lead
to a progressive loss of brain function
due to a loss of neurons over time
• 50,000 Americans a year are
diagnosed with Parkinson’s disease
• Caused by a loss of dopamine-
producing cells deep inside the brain
(substantia nigra)
• Dopamine loss leads to tremors, weakness, poor balance,
loss of dexterity, muscle rigidity, reduced sense of smell, inability
to swallow and speech problems
           Parkinson’s Disease
• Adult neurons will not repair
themselves when damaged (& no cell
division)
• Most treatments involve drugs (like L-
dopa) that increase dopamine
production or accumulation in the brain
• After 4 to 10 years the drugs become
ineffective leading to a poor quality of
life for the patient
• One new idea is to introduce fetal
neurons which can establish connection
with other neurons
     Fetal neuron transplant
• Drill hole in skull
• Surgically inject neurons into
affected areas (fetal tissue
comes from embryos/fetuses
from accident victims/legal
abortions)
• Successful in rodents
• Over 100 patients have
received such transplants
• Although they haven’t
provided full recovery, relief by
over 40% has been shown in
some cases
            Spinal cord injuries
• Nearly 2 million worldwide
(10,000/yr in U.S.) suffer a spinal
cord injury
• Paraplegia (lower body) and
quadriplegia (neck down) may
result from injury
• Graft nerve fibers (fetal or adult
neurons) into damaged area to
“bridge” severed cord
• Promising in dogs & rats
• May be possible to use molecules to reduce damage, block
growth inhibitors, & stimulate neuron regeneration all at once
Organ Transplantation
          • Organ transplantation is
          also an area of regenerative
          medicine since loss of organ
          function compromises the
          system
          • 8 million surgeries in U.S./yr
          related to tissue damage &
          organ failure
          • About 4,000/yr die waiting for
          transplant
          • About 100,000/yr die without
          even qualifying for the list
       Transplantation Types
• There are 2 types of transplants.
• An autograft transplants a
patient’s own tissue from one
region of the body to another (ex.
coronary bypass uses vein from leg)
• An allograft transplants from
one person to another. Allografts
account for many human
transplants, including those from
cadavers, living related, and living
unrelated donors (ex. ACL
reconstruction from cadaver) AKA
homograft
               Human Donors
• A “match” must be found to avoid
organ rejection (when recipient’s
immune system recognizes that the
donor is foreign)
• Matching organs requires tissue
typing
   • Based on marker proteins found
   on cell surface of every cell in body
   • Tissue typing proteins are part of
   large group of over 70 genes called
   major histocompatibility
   complex (MHC)
                         HLAs

• One common group of MHC proteins are called human
leukocyte antigens (HLAs) which are found on virtually
all body cells
• Recognize as “self”
• Some are common and found
on most human tissues, while
others are unique to the
individual
• A “match” requires a close
match of several types of HLAs
       Transplant Recipients
• Transplant recipients must take
immunosuppressive drugs
   • Weaken the immune system
   • Minimize organ rejection
   • May cause many infections
   (some may be life-threatening)
• Isabelle Dinoire (pictured right)
received the world’s first partial
face transplant on Nov. 27, 2005
Isabelle
Dinoire
        Xenotransplantation
• Xenotransplantation is the
transfer of cells, tissues, or
organs from one species to
another
• The cells, tissues, or organs are
known as the xenografts
• Baboons once considered
animal of choice
• May become a viable
alternative
• Ethical issues?
          First xenotransplant

• 1st animal-human transplant
in a child (1984) in CA
• Baboon heart into 12-day-old
girl (Baby Fae)
• Lived for 3 weeks after
           Pigs in the Spotlight
• Pigs are now in the spotlight as
an organ source
   • Plentiful
   • Easy to breed
   • Relatively inexpensive
   • Many organs similar in size
   and function to humans
• Concern: Increasing rates of
rejection and viral transfer (from
pigs to humans)
               Transgenic Pigs
• Transplantation scientists
produced cloned pigs to
overcome fears of rejection
• Lack GGTA1 (-1,3-
galactosyltransferase), a
gene that causes pig organs
to be rejected
• GGTA1 is a sugar on the
surface of pig tissues
(foreign antigen in humans)
        Cellular Therapeutics
• Using cells to replace defective
tissues
• Biocapsules are tiny plastic
beads/tubes filled with therapeutic
cells or chemical substance (drug);
implanted
• May contain genetically
engineered cells
• Tiny holes (permeable to nutrient
exchange) allow molecules made by
cells to escape and enter
bloodstream
       Cellular Therapeutics
              Example
• Capsules containing beta cells
(insulin-producing) implanted
in Type I diabetic
• Protect cells from being
attacked by immune cells
(capsule prevents entrance)
• Can provide lasting release of
molecules (but must be changed
every few months)
            Tissue Engineering
• Wear and tear of human body
parts take its toll
• Over 60 Biotech companies in US
are involved in tissue engineering
• Designing and growing tissues for
use in regenerative medicine
applications
• Example: sheets of human skin
for burn victims

• Skin grafts most successful, but also bone structures
• Complex organs (liver & kidney) much more difficult
          Tissue Engineering
• Begin by designing scaffold
made of biological substances
(calcium and collagen)
• Shaped as organ to be
replaced
• “seeding” = growing
human cells on scaffold (act
as seeds to create more cells)
• Bathed in nutrient rich
media
• Cells build layers over time

				
DOCUMENT INFO