Medical Biotechnology Chapter 11 Medical Biotechnology

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

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

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

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

Detecting and Diagnosing Human Disease Conditions Detecting Genetic Diseases

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)

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

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

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

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

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

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

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. http://learn.genetics.utah.edu/content/pharma/intro/ Animation

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

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!)

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

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

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?

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

Gene Therapy How is it done?

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

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

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

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

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

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

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

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

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

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

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

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!

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

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?

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

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

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

Human Genome Project How was this done?

Human Genome Project Revealed disease genes on all human chromosomes