TISSUES FOR RESEARCH
AND TESTING
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Why human cells and tissues are needed for research
he use of human cells and tissues can help us to understand the
complexity and functioning of human body systems and their
control mechanisms. It can also provide information which is
directly relevant to human diseases and their treatment, where
studies on human volunteers would not be permissible. Moreover,
it can avoid the problem of species differences, which can lead to
misleading conclusions when laboratory animals are used.
In addition to facilitating the development of human medicines,
human cells can also be useful in testing the safety and efficacy of
many types of chemicals and products, such as foods, pesticides,
vaccines, cosmetics and various household products.
E
Using cells and tissues instead of animals
xperimental animals, such as rats, mice, guinea-pigs, rabbits,
dogs, cats and non-human primates, have historically been used
being conducted to develop appropriate replacement alternative
methods, including tissue culture (in vitro) procedures.
extensively for research and testing, although much work is now
C
The benefits of using
isolated cells and tissues
ultured cells and tissues can be used in experimental and test
procedures which could not be applied to the whole body, but it
must be remembered that differences in responses may result from
the absence of the control systems which work at the whole-body
level. The use of cells and tissues from humans, rather than
animals, avoids the problem of species differences (see above).
Efficacy – how effectively a substance
produces the desired result.
In vitro – ‘in glass’, i.e. experiments
undertaken outside the body of an
animal, such as cell cultures.
Glossary
Alternative – a procedure which can
replace the need for animal experiments,
reduce the number of animals required,
or diminish the amount of pain or
distress suffered by animals in meeting
the essential needs of man and other
animals.
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Types of human cells and tissues obtained
he kinds of organs and tissues that can be obtained for use in
as well as heart valves, blood vessels and blood cells.
research include the skin, eyes, liver, placenta, lungs and kidneys
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Sources of human cells and tissues
uman cells and tissues are normally obtained directly from
Patients undergoing routine operations, including plastic surgery, can
donors in four main ways: (a) from patients undergoing routine
elect to donate tissue such as skin, for research projects. New mothers
surgical operations; (b) from patients who die in Intensive Care
can also donate their placentas after they give birth. Patients who die
Units; (c) from patients who die in Accident and Emergency Units;
in Intensive Care Units are classified as potential heart-beating donors.
and (d) during post-mortem examinations. The use of organs and
In such cases, tissues can, with permission of the next-of-kin, be taken
tissues for transplantation must have the highest priority, but
for research purposes when the patient is declared to have undergone
where they are unsuitable for this purpose, their use for research
brain stem death. It is also possible to retrieve full-thickness skin tissue,
can be considered.
usually from the abdomen, up to three days after death, during postmortem examinations.
Post-mortem examination – an
examination of a dead body to
discover the cause of death.
Brain stem death – an irreversible
cessation
of
the
integrated
functioning of the entire unpaired
subdivision of the brain.
Glossary
Transplantation – taking tissue or a
whole organ, such as a kidney, from
a donor individual and surgically
introducing it into the body of a
patient to replace a defective tissue
or organ.
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Acquiring human cells and tissues
he amount and variety of human tissue that can be made
In the past, human cells and tissues for research and testing have
available for research purposes is greatly limited by legal, ethical,
often been obtained in an informal way. This has restricted the
cultural and practical factors.
general availability of such material, and has caused problems,
particularly when donors or relatives were not asked for their
There is a formal system in the UK for obtaining human tissue for
informed consent in an acceptable way. Obtaining informed
medical purposes, that involves transplant co-ordinators and
consent involves providing a written statement of how and why the
couriers who work in conjunction with surgical staff at hospitals.
tissues and cells would be used, disclosing any potential risks to
Transplant co-ordinators can often assist in the supply of tissues
the donor (or the relatives), followed by an opportunity for further
and organs that are unsuitable for transplantation or are surplus to
discussion, so that the donor (or the relatives) can freely make a
other medical requirements.
personal and educated decision.
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Human research tissue banks
t is advantageous to have a formal procedure for acquiring,
according to demand. The tissue can be monitored for disease status
processing and distributing human tissue. To take account of
and other properties. Also, tissue banks can demand that researchers
important ethical, legal and scientific requirements, human research
have obtained ethical approval for their work.
tissue banks are being established in several countries, including
the UK.
All human cells and tissues for research and testing should be
accounted for by logging tissues onto a computerised database, in
Tissue banks can establish call centres, so that tissue can be collected
order to monitor their use and distribution. Donor confidentiality can be
rapidly and safely. Human tissue banks are staffed by people who can
maintained by using an anonymous tracking system.
process the tissues according to the specific requirements of
individual researchers, and can maintain stores of tissue to be supplied
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Safety issues
here are potential safety problems due to possible
contamination of tissues with disease-causing viruses, such as
HIV and hepatitis. It is not possible to screen living patients for
these diseases without their consent.
Some examples of how human cells and
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tissues are used
uman tissues can be used in many different ways, ranging from
fundamental studies conducted to gain an understanding of the
structure and function of human cells in health and disease to
Studies on human tissues are needed as alternatives to using
efficacy and safety testing. Both types of studies can also involve
human volunteers, as well as to replace
experiments to see how substances might be altered chemically in
the use of animals. This is because more
the body, as a result of enzyme action (metabolism), especially by
needs to be known about how a new
using human liver cell models.
chemical or medical treatment will affect
humans before clinical trials in humans are
Also, human cells can be used to model the absorption of
conducted. Such studies can reduce the
chemicals and their passage across and through various barriers in
chances
the body, such as the intestinal wall, the blood-brain barrier
threatening toxicity, like that seen when a
(passage into the brain) and the skin (e.g. with human skin models).
new antibody treatment for leukaemia,
In this way, many cosmetics products and their ingredients are now
TGN1412, was tested on six volunteers in
being assessed for toxicity, such as skin irritation.
March 2006.
of
unexpected
and
life-
In safety and efficacy testing, once the first studies with human
cells in culture have been completed, subsequent tests might
involve animals and also volunteers and patients. However, these
later investigations are often conducted only on those chemicals
that have performed satisfactorily (i.e. that have the desired
therapeutic activity without toxicity) in the earlier tests.
Ingredients – substances that
are used to make a finished
product.
Irritation – reversible damage
to tissues, such as the eye and
skin, causing redness and
soreness.
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Glossary
Metabolism – chemical and
physical processes within the
body that alter a chemical.
Conclusions
he use of human cells and tissues can provide the basis for the
However, the main constraint on using human cells and tissues is
development of very useful and predictive methods for replacing a
their safe, reliable, efficient and ethical supply to researchers. The
wide range of animal experiments. In particular, the use of human
advent of human research tissue banks should help to meet these
cells and tissues can be more beneficial than using animals by
needs, but it is crucial that volunteers, patients and relatives of
providing more-relevant information.
deceased individuals are encouraged to donate tissues, following
receipt of the necessary information and reassurances and are
convinced that the proper procedures will always be followed.
FRAME
Fund for the Replacement of Animals in Medical Experiments
FRAME was founded in 1969, to promote the concept of alternatives to the use of laboratory animals in medical research and toxicity testing. FRAME is dedicated
to the scientific development, acceptance and use of replacement alternative methods, on which the long-term aim of eliminating the need for animal experiments
altogether unavoidably depends. FRAME recognises that animals may still have to be used for some essential objectives to be achieved, and considers that the
most immediate prospects for progress lie in reducing their numbers and in refining the procedures applied to them, so as to minimise their suffering.
Russell & Burch House, 96-98 North Sherwood Street, Nottingham NG1 4EE
Telephone: 0115 958 4740 • Fax: 0115 950 3570 • email: [email protected] • website: http://www.frame.org.uk
Regd. Charity No. 259464
FRAME© Focus/HumCells/v2/06
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