Unit K: Challenges to Biomedical Research

Objective BT11.01: Interpret personal beliefs about

biomedical research

Interpret personal beliefs about biomedical research.

Beliefs about biomedical research What do you believe?

Differences between fact and opinion Fact: information & ideas that can be supported

by data & can be proven Opinion: a belief not based on certainty

Fact vs. myth in research Role of animals in society

Objective BT11.02:Analyze transgenic

animals.

Analyze transgenic animals

Early beginnings Biotechnology – collection of scientific

techniques that use living cells and molecules to make products and solve problems

1. Transgenic organisms = Organisms that contain another species’ genes within their chromosomes

transgenic animals

2. Historically – used in selective breeding of livestock, controlled plant pollination, and microorganisms to bake bread, brew beer and make cheese

transgenic animals

3. This is accomplished by transferring specific genes from one species to another

4. First transgenic organisms were bacteria

transgenic animals

5. Scientists around the world use customized transgenic animals for their own research

6. Species include sheep, goats, cows, chickens, pigs, mice, rabbits, rats, chickens and fish

Benefits of transgenic animals

Animal models Pharmaceutical production Organ donors Livestock improvement

Production of transgenic animals The transgene (which contains the DNA

the scientist wants to transfer) is introduced into a single-cell embryo

The embryo is transferred to a surrogate mother of the same strain

Success rate is low (10%-30%) in mice

Success rate decreases in mammals

Care of transgenic animals

Most do not require special care

Some develop a susceptibility to disease

Government’s role in transgenic research U.S. Patent and Trademark Office

issues patents for transgenic animals

Only government policy is the NIH Guidelines for Research Involving Recombinant DNA Molecules

Ethical considerations1. People opposed to transgenic animal research

believe: Increases animal suffering Animals with altered genetic characteristics

could threaten our environment, our health and food supply

Scientist are “playing God” Concerned that scientist will use these

techniques on humans

2. Beliefs of people who favor transgenic animal research Transgenic animal models provide a powerful new way to

study diseases Vital substances needed by the human body may soon be

available at a reasonable cost Sufficient numbers of human organs are not available for

transplantation and transgenic animals may provide a new source of organs

Transgenic techniques may one day be used to treat human diseases such as sickle cell & cancer

Future of transgenic animals

Current research limited to transferring a small amount of genes at a time

Much work remains to be done to fine-tune techniques

Possible effects of foreign DNA remains a concern

The use of transgenic models is an established part of biomedical research in numerous fields: Immunology Pharmacology Neurology Cancer research

“pharming” although still in the research phase, may soon dramatically increase the availability of scare and much-needed human substances, and at a much lower cost

Biotechnology companies are already producing transgenic pigs whose offspring may alleviate the desperate shortage of organs for human transplantation.

Transgenic pigs with human histo-compatibility genes have been bred in the hope that their "humanised" organs will not be rejected by a patient's immune system. Although in its infancy, if successful, this research could transform the lives of the many patients awaiting organ transplants

From SGK Gene-based biomedical research offers one of the best hopes yet

for curing the major diseases which still afflict mankind. The use of transgenic animals is central to realising that hope and offers the potential for the use of fewer animals in more targeted experiments. We must be clear. There are only two alternatives to using animals. One is to use humans in basic research; the other is to delay or even give up the search for desperately needed new treatments and cures. The appropriate use of transgenic animals is a positive development with potential for significant medical benefits. The challenge is for governments, industry and society to ensure that transgenic research continues to be sensitively carried out for proper medical ends in a suitably balanced regulatory environment.

Objective BT11.03:Evaluate therapeutic vs. reproductive

cloning.

History of cloning Dolly the sheep Born: 5 July 1996 Birthplace: Edinburgh, Scotland Died: 14 February 2003 (euthanization)

Best Known As: The first cloned mammal Dolly was history's first cloned mammal. In February of 1997 it was announced that

the biotechnology firm PPL Therapeutics and the Roslin Institute of Edinburgh, Scotland had successfully cloned a sheep, under the direction of Dr. Ian Wilmut. Cells from the udder of a pregnant six year-old sheep were inserted into the uterus of another sheep to develop, and Dolly was born in July of 1996. (Her name was a sly nod to singer Dolly Parton.) Dolly had the DNA of her source, making her the first mammal successfully cloned using adult cells. Dolly was put to sleep in 2003 after doctors detected progressive lung disease, though she had only reached half the life span of a typical sheep.

Very few scientists believe human cloning (reproductive cloning) should be permitted

Many scientists in favor of therapeutic cloning – the procedure used to produce embryonic stem cells that theoretically can be used to treat diseases

What is a clone? Clone = precise genetic copy Reproductive cloning is really somatic cell

nuclear transfer (SCNT) In therapeutic cloning, the embryo is not

placed in a surrogate, but rather, undergoes cell division in the lab until it reaches blastocyst stage

Obstacles to reproductive cloning using animals

Success rate very low Vast majority of problems occur during fetal

development Additional problems show up after birth and

years later “Large offspring syndrome” = cloned newborns

20-30% larger than usual, making it hard to deliver unborn babies

Embryonic and adult stem cells

Adult stem cells Multipotent stem cells Exist in very small numbers throughout the

body Most accessible ones are the blood stem cells

that reside in bone marrow

Embryonic stem cells Called pluripotent stem cells Have the potential to become many types of cells Embryonic stem cells occur at about 4 days of cell

division

cloning, therapeutic cloning, and stem cell research

Goal of reproductive cloning is to create a new organism, human or animal

Goal of therapeutic cloning is to produce embryonic stem cells

Identical Twins

Natural cloning Takes place during the first rounds of cell

division after conception when each cell had the potential to form a fetus

Human stem cell research 2001 legislation allowed federal funding of

research using 64 existing human embryonic stem cells

Same legislation declared no federal funds for additional research.

Obama has overturned this in his first year of office allowing funding for new lines of stem cells

Therapeutic potential of stem cells Researchers must use existing human stem cell

lines for research or find private funding sources

Creation of embryonic stem cells does not use fertilized egg

On the other hand, it does have the potential to become a living thing if transplanted into the uterus

Question – is life destroyed if the stem cells are removed from the blastocyst four days later?

Therapeutic potential of stem cells (con’t) Real advantage of stem cells – permits the

production of perfect-match tissue Scientists have found that embryonic stem cells

pick up cues from neighboring cells and differentiate into that cell type

Scientists hope stem cells will be used to treat heart disease, Parkinson’s disease, other disorders of the nervous system

Objective BT11.04:Debate pros and cons of animal research

and animal rights.

Debate pros and cons of animal research and animal rights.