In kidney transplants a diseased
kidney is replaced with a healthy one from a donor.
You can function well, with care, with
only one kidney.
This the case if e.g. a living family
member donates one of their kidneys to another family member.
This situation gives the best chance of
tissue matching and minimises the danger of rejection by the kidney
recipient.
Source of kidney organs
Kidney transplants are one of
the most common organ transplant operations done in our modern health
service (eg the NHS of the UK).
The only cure for serious kidney
disease is to have a kidney transplant, hopefully from a suitable matching
donor.
The donor can be a relative
donating one of their kidney's or a fatal accident victim e.g. somebody who
has died suddenly.
The person who has died must be
on the donor organ register or carrying a donor card (providing
relatives agree to the organ donation) - this is the current
situation in UK Law - but it may change.
Any donated organs must be
stored in cold conditions, for as shorter time as possible, to
minimise tissue deterioration.
Since we have two kidneys, one
can be transplanted from a living person to the kidney failure
recipient, but with some residual risk to the donor.
In the surgical operation the
recipient's abdomen is opened below the navel and the new kidney
connected to an artery and vein so it can function with full blood
supply.
The kidney is further
connected to the bladder for urine collection.
The kidney should, at least
partially, work immediately, but it may take several weeks to be
fully working.
It is a complex operation
taking 2-3 hours.
Problems with kidney transplants
However, the donor kidney may be
rejected by the immune system unless precautions are taken.
The immune system treats the
transplanted tissue as 'foreign' and its cells are attacked by
antibodies.
Transplant
rejection
1.
The white blood cells of the organ recipient sense the antigens of the
cells of the transplanted kidney are foreign and not part of the body of
the transplant patient.
2. The
recipient's white blood cells respond to the perceived 'foreign'
antigens by producing matching antibodies
3.
The antibodies attack the 'donated' kidney cells and destroy them and so
the kidney transplant is rejected.
Therefore, precautions must therefore be
taken to minimise the risk of kidney rejection.
(i) You can test how well the
donor's kidney tissue type closely matches the recipient's kidney
tissue.
The tissue-type is based on
the cell's antigens.
The more similar the antigens
of the donor and recipient's kidney cells, the greater the
chance of organ acceptance i.e. the less chance patient's white
blood cells identify the donor's antigens as 'foreign' and
produce antibodies to attack the donated organ.
(ii) The patient needs to be treating
with immunosuppressant drugs to prevent organ rejection, but it may still happen.
These drugs are designed to
suppress the patient's immune system to stop it attacking the
cells of the transplanted kidney tissue.
Unfortunately, these drugs
reduce the body's white cells ability to produce antibodies, so
they won't attack the kidney cells of the donated organ.
So, these drugs make the
patient more susceptible disease that would normally be
counteracted by their immune system - there is a risk of both
infection and cancer.
There are also problems with
availability of kidney organs, e.g. a long waiting list and the cheaper dialysis is
often used as an interim treatment.
Antigens are proteins
on the surface of cells., and a recipient’s antibodies
(from white blood cells of the immune system) may attack the antigens
on the donor organ as they do not recognise them as part of the recipient’s
body and so the transplanted kidney is rejected.
So, summarising - in order to
minimise rejection of
the transplanted kidney:
A donor kidney with a ‘tissue-type’ similar to
that of the recipient is used - which is where a generous relative can mean
the difference between life and death.
The recipient is treated with
drugs that suppress their immune system response to reject the
kidney transplant.
Tests for blood grouping and
compatibility tables are part of the procedure to give the
transplant the best chance of not being rejected.
Dialysis or transplant?
Advantages and Disadvantages - the 'Pros and Cons'
In the long run, transplants are
cheaper than dialysis, but there is a shortage of donated kidney organs for
transplant operations.
Organ donation involves
ethical issues for us and other animals.
Some people may think it is
wrong to use parts of other peoples bodies.
Relatives may override the
wishes of the deceased even though they may have carried a donor
card.
Some poor people are prepared
to sell one of their kidneys for money - should this be allowed
to increase the availability of organs?
Should we transplant organs
from animals? but there are concerns over cross-species
infections.
What animal rights involving
breeding animals specifically for a particular organ like the
kidney?
Will biotechnology enable us
to grow complex organs like the kidney in the future?
There is a long waiting list for
surgery, but
at least dialysis keeps patients with kidney failure alive, and
increases the chance of undergoing kidney transplant surgery!
For elderly patients, dialysis
can reduce life expectancy due to complications - maybe due to other
underlying health problems.
Dialysis patients can suffer from
sudden falls in blood pressure, and they must always be on the
lookout for signs of infection.
Without a kidney transplant,
dialysis patients must continue with the treatment for the rest of
heir lives.
A kidney transplant gives the
patient a much better freedom of lifestyle - greater independence
and general quality of life - no need to go to a medical centre for
dialysis or receive dialysis in the home.
Patients with other underlying
health issues like heart disease may not be able to withstand the
stress of transplant surgery, so dialysis is the only option to stay
alive.
Dialysis patients must take great
care in lifestyle e.g. no smoking, minimum alcohol and avoid excess
weight.
Many of the points raised here
apply to the advantages and disadvantages of other transplant
procedures.
