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BIOTECHNOLOGY AND
MEDICINE
Lecture 8
Madam Noorulnajwa
Diyana Yaacob
PPK Bioproses
Lesson Contents
1. Detecting and Diagnosing Human
Disease Conditions
2. Medical Products and Applications of
Biotechnology
3. The Potential of Regenerative Medicine
4. Gene Therapy
5. The Human Genome Project
1.
Detecting and Diagnosing
Human Disease Conditions
Models of Human Disease
• A number of human genetic diseases also
•
occur in model organisms
Can therefore use model organisms to identify
disease genes and test gene therapy and
drug-based therapeutic approaches to check
their effectiveness and safety in preclinical
studies
1.
Detecting and Diagnosing
Human Disease Conditions …….
cont.
• Extremely important because we cannot
•
•
manipulate human genetics for experimental
purposes
Extremely important because we cannot
manipulate human genetics for experimental
purposes
Many genes in different species have been
shown to be similar to human genes based on
DNA sequence – called homologs
Detecting and Diagnosing Human
Disease Conditions ……. cont.
Mus musculus – house mouse
Escherichia coli - gram-negative
model organism
Male (left) and female Drosophila melanogaster
Detecting and Diagnosing Human
Disease Conditions ……. cont.
Biomarkers for Disease Detection
•
•
•
Early detection of disease is critical for providing the
best treatment and improving the odds of survival
With the right diagnostic tools, may be possible to
detect most every disease at an early stage
Biomarkers – typically proteins produced by diseased
tissue or proteins whose production is increased when
a tissue is diseased
• PSA, prostate-specific antigen
Detecting and Diagnosing Human
Disease Conditions ……. cont.
Detecting Genetic Diseases
• Testing for chromosome abnormalities
• Amniocentesis -
fetus is 16 weeks of age
• Take a sample of amniotic fluid
• Create a karyotype
• Chronic villus sampling (CVS) – fetus is 8-10
weeks old
• Remove a small portion of a layer of cells called the
•
chronic villus that helps form the placenta
Create a karyotype
Detecting and Diagnosing Human
Disease Conditions ……. cont.
Detecting and Diagnosing Human
Disease Conditions ……. cont.
Detecting Genetic Diseases
• Testing for chromosome abnormalities
• Fluorescence in situ hybridization (FISH) – new
technique for karyotyping
• Useful for identifying missing chromosomes and
extra chromosomes, but much easier to detect
defective chromosomes
Definition
Karyotypes describe the number of chromosomes, and
what they look like under a light microscope.
A karyotype is an organized profile of a
person's chromosomes. In a karyotype,
chromosomes are arranged and numbered by
size, from largest to smallest. This
arrangement helps scientists quickly identify
chromosomal alterations that may result in a
genetic disorder.
Detecting and Diagnosing Human
Disease Conditions ……. cont.
Testing for chromosome abnormalities
2.
Medical Products & Applications of
Biotechnology …….. cont.
1. Pharmacogenomics – Customized Medicine



Pharmacogenetics is referred to the study of
genetics influence on individual respond to drugs.
Designing the most effective drug therapy and
treatment strategies based on the specific genetic
profile of a patient
Individuals can react differently to the same drugs

Different degrees of effectiveness and side effects
because of genetic polymorphisms
2.
Medical Products & Applications of
Biotechnology …….. cont.
2.
Medical Products & Applications of
Biotechnology …….. cont.
2. Improved Drug Delivery

Maximize drug effectiveness


Drug solubility, drug breakdown, drug elimination
Microspheres – tiny particles that can be filled with
drugs.



Average particle size from 1 to 50 microns
Made from materials that closely resemble lipids found in
cell membranes
Mist sprayed in the nose to treat lung cancer and other
respiratory illnesses; anticancer drugs; anesthetics for pain
management
2.

Medical Products & Applications of
Biotechnology …….. cont.
Nanotechnology and Nanomedicine

Nanotechnology – involved in designing, building,
and manipulating structures at the nanometer scale


nm is 1 billionth of a meter
Nanomedicine – applications of nanotechnology to
improve human health


Nanodevices to monitor blood pressure, blood oxygen
levels, hormone concentrations
Nanoparticles that can unclog arteries, detect and
eliminate cancer cells; smart drugs that could seek out
and target specific cells
2.
Medical Products & Applications of
Biotechnology …….. cont.


MRI contrast agent is a group of contrast
media/substance used to improve the
visibility of internal body structures in medical
imaging, e.g. magnetic resonance imaging
(MRI)
Therapeutic: Relating to drug/medicine used
for disease treatment.
2.

Medical Products & Applications of
Biotechnology …….. cont.
Vaccines and Therapeutic Antibodies



Cancer vaccines – injected with cancer cell
antigens to stimulate immune system to attack
cancer cells
Vaccine for Alzheimer’s disease
Monoclonal Antibodies – purified antibodies
that are very specific for certain molecules


Cancer cells, arthritis, and Alzheimer’s Disease
Treat addiction to harmful drugs
2.
Medical Products & Applications of
Biotechnology …….. cont.

Antibodies - Are proteins found in blood
serum which have specific reactivity with the
corresponding antigen.

Antigens - Are substances that when introduced
into the body stimulates the production of an
antibody. Antigens include toxins, bacteria,
foreign blood cells, and the cells of transplanted
organs.
Monoclonal antibody - Monoclonal antibodies
are proteins produced in the laboratory from a
single clone of a B cell, the type of cells of the
immune system that make antibodies

3.

Regenerative Medicine
Regenerative Medicine – growing cells
and tissues that can be used to replace or
repair defective tissues and organs
3.
Regenerative Medicine
1. Cell and Tissue Transplant
• Fetal tissue grafts
• Organ transplantation
• Cellular therapeutics
3.



Regenerative Medicine
Fetal tissue graft/implant is a therapy where
tissue from fetus is implanted to a patient for
treatment of disease.
Fetal tissue is unique since it is fast growing and
has a lower possibility of rejection from the
host's cells.
Use for treating Parkinson’s disease, Alzheimer’s
disease
3.
Regenerative Medicine
2. Tissue Engineering
• May provide tissues and organs that can be
•
•
used to replace damaged or diseased tissues
1990s Dr. Charles Vacanti revealed a mouse
with an engineered ear growing on its back
• Seeded with cells from a cow
• Just the outer ear without the inner ear
structures that actually detect sound
Human bladders, rudimentary kidney

Cell therapy - describes the process of
introducing new cells into a tissue in order to
treat a disease. Cell therapies often focus on the
treatment of hereditary diseases.
4.
Regenerative Medicine
Stem Cell Technologies
• What are stem cells?
• Fertilization of egg by sperm results in a
zygote
• Zygote divides rapidly to form a compact
ball of cells called a morula
• Morula develops into embyro consisting of
a small hollow cluster of cells called a
blastocyst

A morula is an embryo at an early stage
of embryonic development.
What are stem cells?
• Two layers to the blastocyst
• Outer layer forms the placenta
• Inner cell mass is the source of human embryonic
stem cells (hESCs)
• hESCs have the ability to undergo
differentiation
•
•
Maturation process in which cells develop specialized
functions
Eventually can differentiate to form all of the more than
200 cell types in the human body
hESCs - human embryonic stem cells

The blastocyst is a structure formed in
the early embryogenesis, after the
formation of the morula.
What are stem cells?
• Source of hESCs
• Embryos left over from IVF
• Embryos created by IVF from sperm and egg
cells donated for the purpose of providing
embryos for research materials
• hESCs can self-renew indefinitely to
produce more stem cells
• Create cell lines
Can adult stem cells do everything
embryonic stem cells can do?
• Cells of matured adult tissue can also be
•
•
cultured and differentiated to produce other
cell types
Small in number and not yet discovered in all
adult tissues
Can differentiate into another different
specialized cell type, but may not be as good
as hESCs
Potential Applications of Stem Cells
• Using stem cells to make white blood cells is
becoming an effective way to treat leukemia
• Stem cells from umbilical cord blood used to
•
•
•
treat sickle cell anemia and other blood
deficiencies
Stem cells from fat have been used to form
bone tissue in the human skull
Repair of heart cells
Adult stem cells isolated from brain and used
to make neurons in culture
What Is Sickle Cell Anemia?

Sickle cell anemia (uh-NEE-me-uh) is the most
common form of sickle cell disease (SCD). SCD is a
serious disorder in which the body makes sickleshaped red blood cells. “Sickle-shaped” means that
the red blood cells are shaped like a crescent.
3.

Gene Therapy
Gene therapy is the delivery of
therapeutic genes into the human body
to correct disease conditions created by
a faulty gene or genes
• How are genes delivered?
• How can genes be sent to the proper tissues
•
and organs?
Can it be effective and safe?
Different Delivery Systems are Available

In vivo versus ex vivo
• In vivo = delivery of genes takes place in the
•
body
Ex vivo = delivery takes place out of the body,
and then cells are placed back into the body
11.3 Gene Therapy


How is it done?
Two primary strategies
• Ex vivo gene therapy
• Cells are removed from the patient, treated with
techniques similar to transformation, and then
reintroduced to the person
• In vivo gene therapy
• Introducing genes directly into tissues and organs in
the body
• Challenge is delivering genes only to intended
tissues and not tissues throughout the body
11.3 Gene Therapy
11.3 Gene Therapy

Vectors for Gene Delivery
• Rely on viruses as vectors
• Use viral genome to carry a therapeutic gene or
genes and use virus itself to infect human cells,
introducing the gene
• Adenovirus (common cold)
• Influenza virus (flu)
• Herpes virus (cold sores, some cause STD)
• Must make sure the virus has been genetically
engineered so that it can neither produce
disease nor spread throughout the body
11.3 Gene Therapy

Viral Infection of Human Cells
• Bind to and enter cells; release genetic material
•

(usually DNA) into nucleus or cytoplasm
Human cell now acts as a host to reproduce the
viral genome and to produce viral RNA and
proteins
Make Good Vectors
• Efficient at infecting many types of human cells
• Retroviruses (HIV) permanently insert their DNA
•
into host cell genome
Some viruses infect only certain types of cells –
good for targeted gene therapy
11.3 Gene Therapy

Other Gene Delivery Options
• Naked DNA – DNA by itself that is injected
•
directly into body tissues
Liposomes – small, hollow particles made of
lipid molecules
• Packaged with gene and injected or sprayed into
tissues
11.3 Gene Therapy

Antisense RNA Technology
• A way to block translation of mRNA molecules
•
•
to silence gene expression
Called RNA or gene silencing
Promising way to turn off disease genes
• Used successfully in cell culture, but has yet to live
up to its promise as a treatment for disease
11.3 Gene Therapy

RNA interference (RNAi)
• Double-stranded RNA molecules are delivered into
•
•
•
cells where the enzyme Dicer chops them into 21nt-long pieces called small interfering RNAs
(siRNAs)
siRNAs join with an enzyme complex called the
RNA-induced silencing complex (RISC)
RISC shuttles the siRNAs to their target mRNA
where they bind
siRNA-bound mRNAs are degraded so they cannot
be translated into a protein
11.3 Gene Therapy
11.3 Gene Therapy

First human gene therapy – SCID patient
in 1990
• SCID is severe combined immunodeficiency
• Defect in gene called adenosine deaminase
(ADA)
• Produces an enzyme involved in the metabolism of
nucleotide dATP
• Accumulation of dATP is toxic to T cells
• Without T cells, B cells cannot recognize antigen
and make antibodies
• Ex vivo gene therapy successful
11.3 Gene Therapy

Cystic Fibrosis – two defective copies of a
gene encoding a protein called cystic
fibrosis transmembrane conductance
regulator (CFTR)
• Normal protein serves as a pump to remove
•
chloride ions from cell
Produced by many cells in the body – skin,
pancreas, liver, digestive tract, male reproductive
tract, and respiratory tract
• Extremely thick sticky mucus in airways; infertility;
extremely salty sweat
11.3 Gene Therapy
11.3 Gene Therapy

Challenges Facing Gene Therapy
• Potential risks of viruses as vectors
• Death of Jesse Gelsinger in 1999 due to
complications related to adenovirus vector
• Death of 2 children in France in 2002
• Temporary cessation of a large number of gene
therapy trials and FDA stopped most retroviral
studies
• Greater patient monitoring
11.3 Gene Therapy

Challenges Facing Gene Therapy
• Can gene expression be controlled?
• Can we safely and efficiently target only the
•
•
•
•
cells that require the gene?
How can gene therapy be targeted to specific
regions of the genome?
How long will therapy last?
Will immune system reject?
How many cells need to be corrected?