1. Medical Biotechnology
Chapter 11
Medical Biotechnology

2. Detecting and Diagnosing Human Disease Conditions
Models of Human Disease
Identify diseases and test therapies before clinical trials in humans
Clinical trials: three phases
Phase I: safety studies- safe dose and how to administer the dose (ADME)
Phase II: few hundred patients for the purpose of testing effectiveness
Phase III: effectiveness compared to other drugs –involve thousands of patients often with different backgrounds and stages of illness throughout the country

3. Detecting and Diagnosing Human Disease Conditions
Models of Human Disease
Rat gene, ob, also found in humans therefore homologous
Codes for a protein hormone called leptin if missing leads to obesity
Found that treating obese children defected in this gene with leptin decreases their weight

4. Detecting and Diagnosing Human Disease Conditions
Models of Human Disease
Organism has 959 cells, 131 of them are destined to go through apoptosis
Study programmed cell death in this organism
Programmed cell death important to correct development of the fetus and improper cell death is implicated in: Alzheimers, Lou Gehrig’s, Huntington’s, Parkinson’s

5. Detecting and Diagnosing Human Disease Conditions
Models of Human Disease
Heart attack mice
Defect in cholesterol uptake

6. Detecting and Diagnosing Human Disease Conditions
Detecting Genetic Diseases

7. Detecting and Diagnosing Human Disease Conditions
Detecting Genetic Diseases
Testing for chromosome abnormalities and defective genes
Amniocentesis (Test at 16 weeks - karyotype)
Chorionic villus sampling (Test at 8 to 10 weeks - karyotype)

8. Detecting and Diagnosing Human Disease Conditions
Detecting Genetic Diseases
Testing for chromosome abnormalities and defective genes
Fluorescence in situ hybridization (FISH)
Fluorescence probes that are specific for chromosomes and/or genes
Spectral karotype

9. Detecting and Diagnosing Human Disease Conditions
Detecting Genetic Diseases
Testing for chromosome abnormalities and defective genes
RFLP (restriction fragment length polymorphisms)

10. Detecting and Diagnosing Human Disease Conditions
Detecting Genetic Diseases
Testing for chromosome abnormalities and defective genes
ASO allele-specific oligonucleotide analysis

11. Detecting and Diagnosing Human Disease Conditions
Detecting Genetic Diseases
Single Nucleotide Polymorphisms (SNPs)
One of the most common forms of genetic variation
Estimated that one SNP occurs approximately every 1,000-3,000 bp in the human genome
99.9 percent of the DNA sequence will be exactly the same –> 80% of 0.1 percent variation will be SNPs
Most have no effect because they occur in non-protein coding regions (introns)
10 pharmaceuticals donated millions in a collaborative partnership called the SNP Consortium

12. Detecting and Diagnosing Human Disease Conditions
Detecting Genetic Diseases
Identifying sets of disease genes by microarray analysis
Microarray created with known diseased genes or SNPs
DNA from a patient is tagged with fluorescent dyes and then hybridized to the chip
Binding of a patient’s DNA to a gene sequence on the chip indicates that the person’s DNA has a particular mutation or SNP

13. Detecting and Diagnosing Human Disease Conditions
Detecting Genetic Diseases
Protein Arrays
Chips contain antibodies
Apply blood from a patient
Proteins from disease-causing organisms can be detected

14. Medical Products and Applications of Biotechnology
The search for new medicines and drugs
Pharmacogenomics
Different individuals with the same disease often respond differently to a drug treatment because of differences in gene expression.
Animation

15. Medical Products and Applications of Biotechnology
The search for new medicines and drugs
Oncogenes- genes that produce proteins that may function as transcription factors and receptors for hormones and growth factors, as well as serve as enzymes involved in a wide variety of ways to change growth properties of cells that cause cancer
Tumor Suppressor Genes – regulate oncogenes

16. Medical Products and Applications of Biotechnology
The search for new medicines and drugs
Personalized Medicine
BRCA1 or 2 – increases risk of developing breast cancer
But there are many other cases of breast cancer that do not exhibit this mode of inheritance
They SHOULD be treated differently (i.e. different chemotherapy!)

17. Medical Products and Applications of Biotechnology
The search for new medicines and drugs
Improving techniques for drug delivery
Factors that influence drug effectiveness
Drug solubility
Drug breakdown
Drug elimination
Microspheres – tiny particles that can be filled with drugs

18. Medical Products and Applications of Biotechnology
The search for new medicines and drugs
Nanotechnology and Nanomedicine
nanosensors that can monitor blood pressure, hormone concentrations, unblock arteries, detect and eliminate cancer cells

19. Medical Products and Applications of Biotechnology
Artificial Blood
Started testing of blood in 1980’s for HIV
However it is still not tested in poor, developing countries
There is a need for safe-blood
Possibilities: cell free solutions containing molecules that can bind to and transport oxygen; or blood substitutes such as Hemopure that is made from the hemoglobin of cattle
What does blood matching mean?

20. Medical Products and Applications of Biotechnology
Vaccines and Therapeutic Antibodies
Vaccines stimulate immune system
Also hope that vaccination may be useful against conditions such as Alzheimer’s disease or drug addiction
Using antibodies in some types of therapies: Development of Monoclonal Antibodies

21. Gene Therapy
How is it done?

22. Gene Therapy How is it done?
Delivering the payload: viral vectors for gene delivery

23. Gene Therapy Targets for Gene Therapy Treating cystic fibrosis
Defective cystic fibrosis transmembrane conductance regulator (CFTR)
Normally it serves as a pump at the cell membrane to move electrically charged chloride atoms out of the cells
If cells can’t move chloride out, they absorb water trying to dilute the chloride in the cell
This leads to the production of THICK sticky mucus
Only a temporary fix

24. Gene Therapy Challenges Facing Gene Therapy
Reaction to the vector, an adenovirus, led to the death of Jesse Gelsinger
It raised more questions than answers:
Can gene expression be controlled in the patient?
How long will the therapy last?
What is the best vector?
Animation

25. Regenerative Medicine
Growing cells and tissues that can be used to replace or repair defective tissues and organs

26. Regenerative Medicine
Cells and Tissue Transplantation
50,000 Americans are diagnosed with Parkinson’s annually
Caused by a loss of dopamine-producing cells deep inside the brain
Leads to tremors, weakness, poor balance, loss of dexterity, muscle rigidity, reduced sense of smell, inability to swallow and speech problems
After 4 to 10 years the drugs become ineffective leading to a poor quality of life for the patient

27. Regenerative Medicine
Cells and Tissue Transplantation
Fetal tissue grafts
The basic idea is to introduce fetal neurons which can establish connection with other neurons
Over 100 patients have received such transplants-shown some recovery
Bridge the gap

28. Regenerative Medicine
Cells and Tissue Transplantation
Organ transplantation
8 million surgeries are performed each year and about 4000 people die waiting
Autograft – transplanting a patient’s own tissue from one region of the body to another- ex. Vein from leg used in coronary bypass-organ transplants are between individuals and so must be checked for compatibility
Histocompatibility complex - >70 genes which produce tissue typing proteins (must match!)
There are many different types of MHC proteins (one group is called human leukocyte antigens or HLAs)- have been using immunosuppressive drugs but there are problems.
Bridge the gap

29. Regenerative Medicine
Cells and Tissue Transplantation
Organ transplantation
Xenotransplantation – transfer between species (pig to human)
University of Missouri scientists have produced cloned, knockout pigs that lack a gene called GGTA1 (or 1,3 galactosyltransferase)
The gene normally codes for a sugar that would be recognized as foreign by humans
Bridge the gap

30. Regenerative Medicine
Cells and Tissue Transplantation
Cellular therapeutics
Involves using cells to replace defective tissues to deliver important biological molecules
Encapsulate living cells into tiny plastic beads (biocapsules)
Capsule protects the cells from rejection but yet allows chemicals to diffuse out
Could be used in Type 1 diabetes therapy
Bridge the gap

31. Regenerative Medicine
Tissue Engineering
Replacement of tissues and organs by growing them in culture
So far skin grafts have been successfully engineered
Bridge the gap

32. Regenerative Medicine
Tissue Engineering
The telomere story
Usually 8 to 12,000 base pair units of the the repeating sequence 5’-TTAGGG-3’. (think of plastic tabs at the end of your shoe laces-prevents unraveling)
A cell’s lifespan is affected in part by telomeres –each time a cell divides, telomeres shorten slightly-which leads to senescence! (aged cells!)
Telomerase repairs telomere length by adding DNA nucleotides to cap the telomere after each round of cell division
Bridge the gap

33. Regenerative Medicine
Stem Cell Technologies
The CDC estimates hat 3,000 Americans die every day from diseases that may one day potentially be treated by stem cell technologies
What are stem cells?
Bridge the gap
Known as
Pluripotent!

34. Regenerative Medicine
Stem Cell Technologies
What are stem cells?
Two major properties:
ES cells can self-renew indefinitely to produce more stem cells
Under the proper growth conditions, ES cells can differentiate into a variety of mature cells with specialized functions
Human ES cells avoid senescene in part because they express high levels of telomerase!
Bridge the gap

35. Regenerative Medicine
Stem Cell Technologies
Adult-derived stem cells do everything embryonic stem cells can do and remove the ethical issue of destroying embryos.
Amniotic-fluid derived stem cells
Reprogramming somatic cells
What are the advantages of having cord blood stem cells frozen indefinitely for a child?

36. Regenerative Medicine
Stem Cell Technologies
Potential Applications of Stem Cells
Done at new york medical college

37. Regenerative Medicine
Stem Cell Technologies
Questions that need to be answered:
Is there an “ultimate” adult stem cell that could turn into every tissue in the body?
Why do stem cells self-renew and maintain an undifferentiated state?
What factors trigger division of stem cells?
What are the growth signals (chemical, genetic, environmental) that influence the differentiation of stem cells?
What factors affect the integration of new tissues and cells into existing organs?
Done at new york medical college

38. Regenerative Medicine
Cloning
Therapeutic Cloning and Reproductive Cloning
Therapeutic cloning to replace defective tissues. Why do researchers prefer the term somatic cell nuclear transfer?

39. Human Genome Project
How was this done?

40. Human Genome Project
Revealed disease genes on all human chromosomes