gene therapy and its potential in treating cystic fibrosis

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Dec 12, 2012 (4 years and 11 days ago)

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GENE THERAPY AND ITS POTENTIAL I
N TREATING CYSTIC FIBROSIS


Sean O’Connor (
SRO13@pitt.edu
), Kevin Hulbert (
KPH12@pitt.edu
)


Abstract
-

Genetic Engineering has been
changing the world
of research and medicine since the late 1900’s
.
Its primary
goal is to improve healthcare of patients in a positive and
more efficient way.

This paper is about the ever
-
changing
field of gene therapy and its potential
to cure
cystic fibr
osis

(CF)
.
We

will describe the complex processes and
transformations involved in the gene therapy treatments of
cystic fibrosis. This research

done on cystic fibrosis is
the
best model for gene therapy treatment of

other illnesses
(Wagner 203).

Current m
ethods of somatic gene therapy transfer
involve the processes of viral and non
-
viral injections into
the cells of the human body. The viral method, using viruses
as vectors, has become the more successful of the two
(Dhillon 1). Their viral transformation
and how they work in
treatment of
Cystic Fibrosis

will be d
iscussed in more detail
in this
paper. Understanding the cystic fibrosis trans
-
membrane
conductance regulator gene (CFTR) is a major
aspect in the treatment of CF. This gene is crucial in
regulating proteins that secrete chloride ions. When
mutated, defective protein processing and production may
ensue, as well as defective chloride secretion. This may
cause a buildup of protein in the lungs and subsequent fatal
lung disease. As a target fo
r gene therapy development, CF
is one of the most extensively researched genetic diseases
(Wagner 203). Unfortunately, the progress of this gene
therapy research has been slowed because of the complexity
of multi
-
genetic diseases (Bosone 1).

Also slowing p
rogress
are the ethical considerations.

Gene

therapy raises ethical
issues with social and political ramifications. These ethical
concerns will be discussed in the paper.


Research is still in
progress
.
Gene therapy treatments of CF have the potential
to i
mprove many lives around the world. The disease causes
a lot of suffering and the development of this research will
advance the quality of patient’s lives while having no
negative impacts on future offspring of the patient.



Key Words


Animal research, B
ioengineering, Cystic
Fibrosis,
Cystic Fibrosis Trans
-
membrane Conductance
Regulator,

Ethics, Genetic Engineering, gene Therapy,
Viral
Transformation



T
HE
G
ENETIC
D
ISEASE
:

C
YSTIC
F
IBROSIS


Before gene therapy, permanent cures for some of the
deadliest dis
eases
seemed

hopeless and
impossible
. No
w

these diseases have the opportunity to be permanently cured.
Cystic Fibrosis is a genetic disease that has caused a lot of
suffering and death in the United States
,

and around the
world. It is fairly common, affect
ing
1 in 2500 Caucasian
newborns [1].


Cystic fibrosis is the result in a variety of genetic
mutations of the Cystic Fibrosis Trans
-
membrane
Conductance Regulator gene (CFTR) in the human genome.

The CFTR gene is found in region q31.2 on the long (q) arm
of human chromosome 7

(figure 1)
.



FIGURE 1

S
hows location of CFTR gene
[2]
.


Two scientists, Collins and Tsui, discovered the location of
the gene at Yale University in 1989.
When functioning
properly,
CFTR codes for the production of a protein made
up
of 1480 amino acids [2]. This protein

product is a channel
for chloride ions and is located in the epithelial cells lining
the lungs, liver, pancreas, reproductive tracts, intestines, and
skin.
For this gene to fire and

cause secretion of Cl
-

ions,

phospho
rylation must occur (
addition of
PO
4
3
-

ion).
The
exact structure of the CFTR protein product has not been
determined through research but
in comparison

to other
transporter proteins, it is the only one with a fifth regulatory
domain.

This domain is where CF can be caused if the right
number of phosphate groups is altered, affecting chloride
transportation.

Also involved in the diagnosis of CF are gene
base pairs.


The vast majority of Cystic Fibrosis cases are due to a
deletion mu
tation of three base pairs in the gene.
This
deletion causes loss of the amino acid phenylalanine located

at position 508 in the protein. T
herefore, this mutation is
referred to as delta F508
. The protein will not fold properly
an
d eventually degrade. Also
,
a mutation in the S341A
position can alter
the affinity and voltage dependence of the
protein, vital to blocking and opening the channels of CFTR
[3]. This change in affinity and voltage may cause less
phosphorylation, rendering
the CFTR protein almost u
seless
and allowing

mucus and bacteria
to

build up
.

The lack of
chlorine in the cells of the pulmonary tract
, when one has
CF, inhibits airway surface liquid (mediated by Cl
-
) to
adjust, in turn preventing periciliar liquid layer (PCL
) to
form

at a correct

height [4
]. This PCL is what “lubricates”
airways allowing mucus and bacteria to pass through
without cl
otting/blocking the airway. When this occurs,
cystic fibrosis

becomes one o
f the deadliest diseases in the
world.

Unlike in earlier years though, there

is now an
opportunity to treat this disease.


Treatment before Gene Therapy


Before gene therapy research, there seemed to be no hope of
curing cystic fibrosis and those who
were

diagnosed with it
were cursed to live a shortened life filled with pain and
infection. The build of mucous in respiratory canals often
caused infection and
sometimes even lung cancer
. Many
patients
are continuously hospitalized and

put on endless
antibiotics

and enzyme supplements. In the 1990’s, it was
predicted that babies diagn
osed with cystic fibrosis could
live up to
40 years

[5
].

Many antibiotic drugs have been
developed to help such as ticarcillin, piperacillin, and
ceftazidime. The use of inhaled antibiotics such as coliston
has proved to be successful in improving pulmonar
y
function in the past. However
,

there are usually cons
involved with most medical treatments. The development of
multidrug resistant microorganisms rises everyday and
continues to cause problems in treating cystic fibrosis.

This
occurs because this treatm
ent method involves large
amounts of intakes of antibiotics
,

making it easier to become
resistant.


Different methods of physical therapy and exercise have
been used to try and clear obstructed airways in patients.

Patients are often put in positions that allow for drainage of
the mucus formed in the lungs while a percussion machine
pats the back or chest to dislodge mucus from the walls of
the airways. Medications such as b
ronchodilators,
mucolytics, and decongesta
nts

are available on the mark
et
but can prove to be costly [5
]
.

The patient is encouraged to
exercise
frequently

because it also helps clear the lungs.
Children often need to be treated by their family members
but with age, may be able to use these techniq
ues on their
own.


Another method used is
lung transplantation. This is an
increasingly
sever
e

me
thod that is very expensive. Selection
for a transplant is also unlikely
because of the
large list of
those who need one
. It is suggested mainly for patie
nts that
experience severe respiratory failure. This treatment, if
successful, allows for normal CFTR proteins to be formed
but normal transplant complications are always possibility.
All of the older methods can help prolong the inevitable
among patients
but over the years, they become very costly
and do not provi
de a permanent solution.

An increase in
research in gene therapy and the development of higher
technologies continues to allow for a promising future.

If
gene therapy technologies can be

perfected

in treating cystic
fibrosis, then a truly permanent treatment may finally be
possible.

The quality of patient’s lives will be improved
significantly.


G
ENE
T
HERAPY AND THE
E
NGINEERING
T
ECHNOLOGY
I
NVOLVED


Genetic engineering research has and continues to
put a lot
of work into developing gene therapy and the technology
involved with it.
Gene therapy is a process involved in
genetic engineering that allows for modification of genes
internally and externally to treat diseases.
Cystic fibrosis
continues to be

the most problematic when seen in the
respiratory tract, so researchers are most attentive to therapy
in this region.
The defect gene for CFTR is cloned and
modified

before it can be inserted in the patient. Chloride
transport is

made possible

in the clon
ed gene,

and this new
product is called wild
-
type CFTR.
The process of cloning
the DNA is made easier with real
-
time quantitative PCR (Q
-
PCR).

PCR is a polymerase chain reaction and its products
can now be measured in real time. A fluorescent signal is
gen
erated from the reaction and is captured by instruments
such as TaqMan Probes, Molecular beacons, and SYBR
intercalating green dyes. The probes are capable of
determining the
expression level

(fundamental step between
genotype and phenotype)

of specific al
lele in comparison to
the allele one nucleotide away.
It measures mRNA
expression, DNA copy numbers, transgene copy number and
expression analysis, allele discrimination, and viral titers [6].
This technology has only recently become a useful factor in
gen
e therapy and provides for the opportunity of using less
expensive instruments. Q
-
PCR generates exponentially a
graph of DNA copies until it plateaus off.

The measurements
that are collected allow for knowledge of exact placement
and expression of the CFTR

gene.
Though these
technologies help the cloning process, the
y cannot help the

next step involving the insertion of the cloned
CFTR. This
continues to be an issue.



FIGURE 2

Plot

showing
real
-
time PCR experiment. Above threshold fluorescent signal
can be detected and used to define PCR cycle number, which is shown on
the x
-
axis
[6]






External strategies prove harder for the
treatment of lung
cells,

so an
in
-
vivo

process is needed.

Vectors must be
applied directly to the target cells for
in
-
vivo

methods.
Vectors are modes of transport for the newly modified
healthy genes.
Many different vectors show

the

promise
of

being successfully
accepted

by h
umans, but viral vectors
show the mos
t promise
.
There are many different types of
viral vectors, each
dif
ferent from the other in regard

to DNA
copying, administration into the
subject, and how it bonds to
the CFTR. There are retroviruses, adenoviruses, lentiviruses,
adeno
-
associated viruses,

and
Nano
-
engineered substances.
Adenoviral and retroviral vectors have been more successful
when tested than other forms of viral vectors.
When the viral
vector route is taken, t
he virus DNA originally starts in the
form of a plasmid, a ring of DNA. The
goal is to get this
virus to deliver the healthy CFTR to a target cell
,

but not to
replicate or form more viruses. The replication gene and the
capsid gene are removed from the viru
s.

A capsid is a shell
that surrounds the virus. The removal of these genes

can be
done
with
recombinant

DNA (rDNA) technology.

Restriction enzymes are used to cleave the DNA at a specific
site
, leaving

two “sticky” ends on the plasmid.
The CFTR
gene is then inserted into the plasmid

and is joined by a
DNA ligase enzyme [7]
. O
nc
e the vector has been built, it

is
placed into a packaging cell line that contains a helper virus
,

as well as

the replication and capsid genes that were
removed
. This packaging cell line combines the elements
with the vector and aids in replicating the vir
us with the new
plasmid in it. Cells become full of the virus and they burst.
This is when they are collected into a pure liquid solution of
viruses. The new virus vector is then put into the infected
unhealthy cells of the lungs.

Methods of injection into

cells
for gene therapy include heat shock, electroporation, viruses
(produced by above description),
and
a gene gun. Heat shock
involves heating the host cells suddenly
,

causing its
membrane to become permeable enough for the new DNA to
pass through. Elec
troporation involves a similar process
where electric shock allows for increased permeability. A
gene gun fires gold particles coated with foreign DNA
segments.
The virus

or injected DNA

infects the cells and
the new DNA
becomes integrated into a specific
location on
chromosome 19. This new DNA successfully codes for the
correct mRNA to produce healthy CFTR cells.

This is the
general way a viral vector works, but adenoviral and
retroviral vectors work slightly differently.




Adenoviruses


Adenoviruses
are medium
-
sized icosahedral viruses
composed of a nucleocapsid and a double
-
stranded DNA
genome [8]. A nucleocapsid is a viral sac that is made up of
a nucleic acid and protein coat. The nucleic acid is what
holds the DNA.
Adenoviruses represent the large
st
non
-
enveloped

virus, as it is just small enough to be transmitted
through the endosome of the epithelial. These viruses are
transmitted into the subject through respiratory droplets or
through fecal routes. Once inside the cell the adenovirus
attaches o
nto the coxsackie
-
adenovirus receptor
(CAR)
on
the mutated cell’s surface through one of its sharp
fibres

[8].
The
CAR

is a protein that acts like a hand, grabbing the
adenovirus and pull it into the epithelial cells of the mutated
gene.
After it passes th
rough the surface of the host cell, the
virus lets the DNA free into the nucleus of the host. This
process has two parts to it. The first interaction with the host
involves the fibre of the virus binding to the cox
-
sackie
receptor of the host. This first p
rocess is fairly simple, but
the second process is far more

complex. Once the
adenovirus is bonded to the CAR, a penton base protein in
the adenovirus binds to an integrin molecule, which acts as a
co
-
receptor to the CAR. This binding causes internalizatio
n
of the virus into the host cell. This binding stimulates the
cell to signal and causes actin polymerization to occur, in
turn allowing the virus to enter an endosome of the host cell.
Actin polymerization is the process of comb
ining DNA
monomers into a p
olymer

so the actin protein in the host can
move the virus into the cell endosome.

After this the
endosome can acidify and break apart
,

releasing the
adenovirus into the cytoplasm of the host. The virus is then
transported to the nuclear pore complex (open
ings in the
nucleus), where the adenovirus can break open allowing the
DNA of the virus to finally enter the nucleus of the mutated
cell [8].


Risky Business


There are some disadvantages to gene therapy. Cost is one of
the major problems. This kind of treatment will become
expensive if the patient needs to keep receiving the
treatment. The issue of response to the treatment is another
factor.
The more times the

treatment is administered to try
and achieve long
-
term affects, the more likely the body is to
become immune to the treatment.
Current treatments of
cystic fibrosis have not proven to be permanent. The affects
will work for a few days but then the cells w
ill turn back to
their incorrect coding of CFTR.
The target cells have been
debated a lot and determination of the exact “parent” cells
has not occurred.

Studies have shown that some patients
have
defections in 100% of their CFTR genes,
and other
patients
have
defections in
as little

as six percent [9
].

The
natural response of the body when foreign material enters it
is to fight it and either kill or remove it. Infecting cells with
the new foreign DNA in the vectors
may cause the patient’s

body to produce a
n immune response against it
,

causing the
patient to become ill. Using viruses as vectors also creates a
risky situation because there is always the chance that the
virus will regain its old ability to spread disease in the
patient. The new DNA may not mak
e it to the right cells that
need to be altered and if it does make it to the right cell, the
vector DNA
may be incorrectly placed.

There are barriers in
the lung that make it more difficult to get the new DNA to
the correct lung cells in the patient. The
mucocillary
clearance defense system can be slowed down with new
drugs such as rhDNase [1].
Finding a safe method to apply
this treatment to the patient

s mucus filled lungs has been
the main
challenge

in gene therapy being affective for good
.

A lot of re
search has been going on in
current and recent

years to help find the best way to administer the healthy
gene into the cell
,

and once that occurs, making the cure
permanent
.

Both are detrimental to making gene therapy a
trusted cure for diseases, but advan
ces are being made.


R
ECENT AND
C
URRENT
R
ESEARCH


Researchers have been working very hard to find out a way
to make gene

therapy successful. If it were
successful, a
plethora of deadly diseases all across the world
could

be
cured. Diseases such as: AIDS, c
ancer,

and

Alzheimer’s
might be things of the past. In 1989, after it was found that
the CFTR gene was the cause of cystic fibrosis

[5]
,
large
-
scale

gene therapy research began
.
Was it just a
coincidence? Or was the fact that a mutated CFTR gene was
found
to

be the culprit of the disease, which

resulted in the
first trials of gene therapy on humans to occur that same
year. In 1989, Dr. Steven A. Rosenberg administered the
first trial of ge
ne therapy to be performed

on a human [9].
The Rosenberg trial involv
ed introducing a retrovirus into
five patients with melanoma.
This trial didn’t involve cystic
fibrosis, yet it was a huge step in curing the disease, as the
number of trials in administering gene therapy rose
exponentially.
“This study demonstrated the fe
asibility of
using retroviral gene transduction in humans and set the
stage for further studies” [9]. Since the first study in 1989,
almost 1,000 clinical gene therapy trials have been
completed or have been approved by doctors and researchers
all over the

world. In 1990, another major gene therapy trial
ensued. The first therapeutic gene therapy trial was allowed
to be performed. Up until 2004, there had been gene therapy
trials in 24 different countries, with the United States
administering the majority o
f them.

These trials used many
different vectors to send the healthy genes into the cells of
subjects. The majority of these being viral vectors (70%).

Of
all trials, 28% of trials involved retroviral vectors and 26%
involved adenoviruses [9]. Non
-
viral ve
ctors are used
because they are less dangerous to the subject than viral
vectors, yet aren’t

as effective. Many diseases have been
tested upon as well,

cancer being the most common. Ten
percent

of the trials were involved in monogenetic diseases,
with one
-
third of those being cystic fibrosis [9].
On March
15, 2012, a groundbreaking occurrence in cystic fibrosis
research occurred. The United Kingdom government just
approved a massive grant for one of the largest research
trials in cystic fibrosis research hi
story. One hundred and
thirty adults and kids with cystic fibrosis will be involved in

large
-
scale clinical trials [10
]. The grant includes 5 million
US dollars to be put towards the clinical research. The
patients will inhale DNA wrapped in fat globules.
Half will
receive a placebo inhalant and the inhalants will be
administered once a month for a year.


Trials with
Adenoviral Vectors


In 1995 a clinical trial involving adenoviral vectors in
treating cystic fibrosis was directed on 1
2 p
atients with
cystic
fibrosis [11
].

The adenovirus was
inserted into the
right nostril first, then the left nostril of the subjects. The
adenovirus was administered in the epithelial of the nostrils
with increasing dosage. After about an hour it was found that
only 58% of the
adenovirus solution remained in the nose.
After the trials
,

statistics showed that there was no real
potential difference in the epithelial of the nostril between
the four cohorts of subjects. The fourth cohort (most
dosage), didn’t differ much at all from

the first cohort (least
dosage). The researchers at the end of the study concluded
that the gene transfer through adenoviruses in th
e nostrils
was not efficient [11
]. Chloride ion transport

was not
increased in the CFTR;
only inflammation was.

Inflammatio
n is somewhat common in studies with gene
therapy. The patient may also completely reject the virus or
have an allergic reaction. These risks are always present, but
positive outcomes do occur much like in 1999.

In ‘
99, a

test

in California

using
a similar

transport method was
successful
.


At Stanford University researchers began a clinical trial
in which adeno
-
associated viruses were administered

to the
patient via aerosols [12
]. These aerosols were inserted
through the nostrils of the patients. Includ
ing inflammation
of the lungs in patients with CF, the sinuses are affected
negatively as well. When the adeno
-
associated virus was
inserted into the nostrils, it was found that there was a
“significan
t reduction in inflammation” [12
]. This study
didn’t sh
ow
that
gene transfer would be successful in the
epithelial of the lungs and cells, but it was a big confidence
booster, that would help pave the way for more CF gene
therapy research in the coming years.


Cationic Liposomes


Current research falls heavil
y on new ways of delivering the
genes efficiently.
With

regards to efficiency, a lot of
research has

turned to developing viral pseudo
-
typing, a new
generation of cationic liposomes, and the use of non
-
viral
vectors with a powerful transfection levels such

as the
Sendai virus [1
2
]. Cationic liposome research involves
mixing cationic lipids with cholesterol and
dioleoylphosphatidyl
-
ethanolamine.

These are bonded to
DNA electrostatically and are allowed to interact and pass
through cell membranes. Research ha
s proven that this
method has shown transfection in the lungs epithelial cells of
mice. This was tried in a human trial by nasal perfusion and
resulted in partial correction of nasal differences but the
patient did succumb to a fever. Other trials had simi
lar
results and modifications of the cationic liposomes are
needed. Some ideas for modification include reducing non
-
essential CpG to reduce infla
mmatory response by patients
[13
]. Research on extending the length of time of the effects
is also crucial bec
ause the main goal is for this treatment to
cure cystic fibrosis permanently. Adenovirus vectors have
proven to be the most efficient with this part of the process.
The latest of developments in adenovirus vectors has shown
high transgenic effects from tre
atment la
sting up to 15 weeks
in mice [13
]. This is good progress but is still a long step
from the intended goal.


Non
-
epithelial Cells


Research on treating alternative non
-
epithelial cells is also
currently in progress. The CFTR defect in immune cells c
an
prevent them from clearing pathogens. Because of this
defect, patients become considerably more vulnerable to
pathogens in the air that may cause illness. Correcting the
defect in these cells would prove to be effective and
beneficial to the patient. Re
search in mutated, CFTR
lacking, mice has
raised

questions about whether or not
inflammatory signals are due to mutated epithelial ce
lls or
deficient lymphocytes [13
]. Correcting CFTR can cause the
lymphocyte channel to work properly again. It is important

to protect the effectiveness of the immune system in a
patient with cystic fibrosis because they are consistently
faced with mucus build up and respiratory infection. Studies
on cystic fibrosis lung
-
transplant recipients have shown that
they exhibit a lar
ger decline in health than those without the
transplant. Correcting the CFTR in non
-
epithelial cells has
been relatively unexplored but offers potential in aiding
patients with cystic fibrosis, much like the other vectors.
This potential can become a reali
ty, but gene therapy
still
may not be the key due to heavy ethical considerations and
arguments.


E
THICAL

C
ONSIDERATIONS


Genetic Engineering is a big part of the medical field. The
medical field has always been limited due to ethics and laws
passed by the

government. Many of the considerations that
go into aspects of the medical field apply to genetic
engineering as well. It is important to realize that not
everyone agrees with genetic engineering, specifically when
it comes to altering the DNA of a fetus.

The govern
ment has
passed laws on any type

of germ line therapy in humans
because the alterations would affect future outcomes of
many generations [13]. The government has not chose
n

to
prevent somatic gene therapy to treat disease
,

so this gives
research

the potential to improve. Genetic engineering is a
fearful advancement because of its risk and its potential.
Many fear that the excitement of the potential of this type of
treatment has led to research trials that may have been too
risky.
Risks need to b
e taken in order to improve civilization
for the better.

Researchers are not sure of what the best way
to transfer the correct genes is
,

and it will take many years of
trials to determine it. Researcher
s have to
check

all the

research and answer many quest
ions before
having

access to
human trials. Many people
believe

that we should be fated to
what we
are

born with and that it is unnatural to try and alter
nature’s course. Some find that going against the natural
way of things is unethical and that
people s
hould not try and
“play
G
od”. People are afraid that instead of gene therapy
being used to cure diseases that the rich will take it to the
extreme and try to purchase “super” children. Many are in
favor of gene therapy as long as it is restricted to curing

diseases that causes pain and suffering to

the families and
the public [14
]. It is normal for people to want the medical
field to continue to advance so that all disease will be cured.
It is also understandable that there are real fears among
people about

growing technologies in the medical field. If
the wrong people in government decided to change the laws,
then all around the world, super
-
humans
could

begin to rise.
Many people also worry about insurance companies using
genetic testing to determine who g
ets covered and who does
not [14
]. This is a real concern because insurance companies
could potentially condemn those with “bad” genes to poor
medical care and the inability to afford medical treatment.



Religion


Many religious people say that it is
unholy to alter the genes
that G
od gave a person.
They claim i
t is a sin and is
wrongful to alter nature with new genetic engineering
technology.
These same people were against the first organ
transplants as well, so the argument is expected.
Polls show
th
at
58% of people disagree with the re
ligious view on gene
therapy [14
]. It is understandable to take into account
people’s religious beliefs but when it comes to passing laws
against it, their beliefs cannot influence the decision because
of
the
separation

of church and state. Who gets to decide
what diseases are worthy of being treated by gene therapy?
This is a common question brought up because it concerns
ethics. It is tough to decide specifically what
a suitable
disease for gene therapy is,

because res
tricting another
disease may cause a person pain and suffering when there is
the potential to cure that person. It is important for the
citizens of the world to stay active in the debates on gene
therapy and to voice their opinions because it is not right
for
any one man to make the decisions concerning gene therapy.


Gene therapy has not been perfected so it can be
unpredictable at times. Using treatment on humans where
there is the potential of viral vectors turning to their natural
viral tendencies
is unethical because it could cause the
patient to become even sicker with allergic reaction or
inflammation. It has become one of the main goals of gene
therapy researchers to perfect making the transfer of healthy
genes safe and consistent. People believ
e that treating
patients with gene therapy may be unethical becau
se of all
the risks involved [14
]. In the medical field, there are always
risks. Progress has been made over the years because risks
have been taken.
However, i
t is important to take the righ
t
risks. After a considerable amount of research has been
conducted and the animal trials have been successful, human
trials are necessary for the advancement of the medical field.
People have always dreamed

about a world without cancer,
AIDS
, and other pa
inful diseases such as cystic fibrosis. The
same risks are often involved in other medical procedures. A
lung transplant has many of the same risks a
s gene therapy if
not more
. They both share the possibility of rejection by the
immune system and inflammat
ion. The lung transplant will
be very expensive and will require many treatments to make
sure that everything is working correctly and that the body is
accepting it. There is always the risk that the new DNA will
make its way to the egg and sperm cells. Th
is causes a lot of
concern because that would affect future
generations. There
has been no

indication of egg or sperm cells being affected
in conducted research trials [14
]. Gene therapy, when
perfected, will involve one treatment that may be painless
and
will cure cystic fibrosis for the rest of the patient’s life
,
thus allowing future generations to occur and even flourish
.


S
USTAINABILITY


With growing interest in environmental awareness and better
solutions for healthcare, engineers must always be awar
e of
sustainability and incorporate its meaning into all of their
work. Sustainability is advancing the quality of life of
civilization while preventing negative effects on future
generations. Engineers are conscious of how their research
affects the envir
onment but also how it affects human life.


Bioengineers strive to improve healthcare technologies so
that the lives of patients may be improved and suffering may
be ended. With the high potential of gene therapy and it
being on the edge of new breakt
hroughs everyday, it will
play a very important role in improving lives of people with
and genetic disorder. Cystic fibrosis causes a lifetime of
suffering not only for the patient but also for their families
and friends. A person with cystic fibrosis has
to spend
portions of everyday doing specific exercises or wearing
expensive pulsating equipment to clear excess mucus in their
respiratory tract. They are constantly dealing with
respiratory tract infections and will spend a lot of time
visiting a hospital
. Nobody should have to live this
expensive and painful type of life. When perfected, gene
therapy promises to abruptly cease the effects of the disease
and allow for the patients and families to live normal and
more comfortable lives. The patient will be

able to live a
longer and healthier life overall. Patients will no longer need
to rely on everyday exercises and equipment. The need for
risky and expensive lung transplants will be removed as
well. Eventually research will find and produce vectors that
a
re effective enough to maintain healthy CFTR genes in the
patient’s respiratory tract for many years. A permanent
solution is the desirable goal but even a solution lasting four
to five years would greatly make someone’s life easier and
would require fewer

expensive hospital visits. Currently
methods of gene therapy are limited by cost of production,
storage, and biosafety issues. The price of gene therapy
when it is further developed will be irrelevant compared to
numerous hospital visits over a lifetime o
f treatment. New
research for treating cystic fibrosis is becoming more
recognized by government funding. The new UK grant is a
major breakthrough in research and will hopefully produce
valuable vector delivery data. The funding of research is
critical for

the advancement of this type of treatment and
breakthroughs will continue to happen. A future without
cystic fibrosis causing suffering requires the necessary
attention of the world and proper funding.


The risks of gene therapy treatments have to be c
arefully
considered because whenever genes are involved, future
offspring may also be affected. The injection of vectors with
new DNA is meant to change a person’s DNA. The risk is
that the patient’s germ line DNA will be affected which is
currently illega
l in the United States. Treating cystic fibrosis
has been targeted in the lungs and respiratory tract so there is
a small chance that new vectors will influence the testicles
or ovaries. This is important because if a problem occurs
with the treatment and
a viral vector becomes activated as a
viral disease, future generations may be unaffected by the
problem.


Gene therapy has a negligible impact on the green
environment but the primary research conducted involves
animal research. Animals such as mice a
re bred with
diseases such as cystic fibrosis for research. The research is
being conducted to improve the quality of human life and
the issue with animal rights activists has already undergone
its course. The technology involved in gene therapy does not
r
equire a vast amount of resources from the environment and
the equipment can be used numerous times.


L
OOKING TO THE
F
UTURE


Genetic engineering has a very promising future
. Research
continues to be well
-
funded and new breakthroughs and
positive results ar
e imminent. Using gene therapy to treat
diseases and cancers will transform the medical field and the
world. If scientists and engineers can perfect the vector
methods used to administer healthy CFTR genes into a
patient

s cell, cystic fibrosis can be cure
d. The gene gun and
aerosol injection are prominent technologies for delivering
the vector but better methods need to be found. New ideas to
aid in the treatment of cystic fibrosis are being developed
such as treating non
-
epithelial affected cells and cati
onic
liposomes. Developing newer and more efficient technology
for delivery is essential in the progress of the therapy.
Research needs to be geared towards finding away for cells
to sustain the effects of gene therapy treatment permanently
or for long per
iods of time. Fifteen weeks of positive results
is nice but is nowhere n
ear as good as giving a patient
a

lifetime without the disease.

It is necessary to fund research
that may lead to improving people’s lives.


Overcoming the
barriers provided by the immune response is also one of the
tougher tasks. The body is always going
to

fight foreign
substances that enter it. This significantly increases the risks
of gene therapy and slows down trials and research.
Many
su
ffer from this

disease

and others similarly devastating
.

People just need some hope and gene therapy is it.

The
adversities facing this breakthrough remain though, s
uch as
religious beliefs, government laws and ethics, and the public
fear of the its potent
ial to play the role of god. New
technology, new treatments, and new ideas scare a lot of the
general public. More human and animal trials need to be
conducted and the government needs to continue to supply
sufficient funding. It is clear that since the di
scovery of the
human genome the future of medicine would be involved
with it. Gene therapy is the solution that mankind has been
waiting for many years and its technology and processes
need to be fully supported by the public in order for it to be
successf
ul.


R
EFERENCES


[1]
Davies, Jane C and Geddes, Duncan M. (July 6, 2001). “Gene Therapy
for Cystic Fibrosis”.
The Journal of Gene Medicine
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Available:

http://onlinelibrary.wiley.com/doi/10.1002/jgm.200/full


[2] “CFTR: The Gene Associated with Cystic Fibrosis”.
The US
Department of Energy, Biological, and Environmental Research.
September
12, 2003. [Online Site]. Available:
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[3] Gadsby, David and Angus Nairn. “Control of CFTR Channel Gating by
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New
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[4] Boucher, RC. “New Concepts of the Pathogenesis of Cystic Fibrosis
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January 1, 2004. Chapel
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[6]
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Knowles, Michael
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[12] Tanne, Janice Hopkins. “US Trial of Gene Therapy for Cystic
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[13] Mueller, Christian and Terrence R Flotte. “Gene Therapy for Cystic
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A
DDITIONAL
S
OURCES


Chang, Patricia L. “Somatic Gene Therapy”.

CRC Press Inc.
1995.

[Online
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y&f=false

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html


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-
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Gene Therapy.net. (2012). “Adenoviral Vectors”. [Online Article].
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http://www.genetherapynet.com/viral
-
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Ginzinger, David G. (Dec 10, 2001) “Gene quantification using real
-
time
quantitative PCR: An emerging technology hits

the mainstream”.
ISEH
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[Online Article]. Available:

http://www.sciencedirect.com/science/article/pii/S0301472X02008068

Richter, Gerd, and Matthew D. Bacchetta. "Interventio
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A
CKNOWLEDGEMENTS


Kevin and I would like to thank our grader, Carol, for all of
her insight and advice on our paper. We would like to thank
Janelle for meeting with Kevin and I and discussing ways to
improve our paper throughout the
process. Finally, we
would like to thank our co
-
chair for her encouragement and
insight.