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May 2007 Posts
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Minnesota Gene Pool Blog

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May 30, 2007

Notes from PH 7200: How to repair a broken heart

Guest Blogger Petrona Lee reflects on Dr. Doris Taylor's talk on using adult stem cells for repairing damaged hearts...

Human beings are approaching the pinnacle of healthcare. It was not many years ago that living to the age of thirty was considered making it to old age. Medical progress has taken quantum leaps in many areas. The invention of such technology as MRI, CAT Scan, Ultra Sound among others has allowed medical personnel to look deep within us with minimum invasiveness. All this has led to innovative medical treatment that in addition to antibiotics has allowed us, at least in the developed countries, to increase our life span by a factor of approximately 2.5. Persons with diseases such as Aids, diabetes, breast cancer, PKU, cystic fibrosis, etc. can look forward to living fairly normal lives due to many of the genomic, technologic, engineering and computer advancements.

Today I received yet another message of scientific leap into not only prolonging life, but much more importantly, improving health and thereby quality of life. Dr. Doris Taylor, from the Cardiac and Vascular division at the University of Minnesota shared with us, what may seem to some, star wars like medicine.

Her team has successfully decellularize and regenerate heart muscles such that the individual is not only able to compensate for damaged tissues, but is able to repair the injury and return to essentially new organs. In fact, she has shown that the entire organ can be regenerated with healthy functioning cells. This is the closest to going shopping for new parts that I have ever heard. A few days ago, I joked to some friends that at a certain age, we should be able to “pick up new parts? just as we can at the auto store. Little did I know that we are approaching its equivalent in the not too distant future.

All kidding aside, this is as close to public health promotion as we have ever been. I can see us somewhere in the future, not only living longer, but without chronic diseases. In fact, based on our genomic profile, we could target which organs are likely to be monitored based on known environmental exposures and regenerate proactively before catastrophic manifestations. We could even predict at what age this would likely be needed because we could do individual aging profile. Is this star wars thinking? Perhaps today, it may be so, but the future may be closer than we think.

Petrona Lee

Reflections from PH 7200: Nutrigenetics testing

Three public health genomics courses are being offered in the 2007 Public Health Institute. Guest blogger, Petrona Lee, is attending the course and provides some reflections on what she finds interesting and important. Today's entry is on the nutrigenetic testing.

Nutrigenetics is one of the upcoming genomic fad. While the underlining theory behind prescribing a diet based on one’s genomic profile has some credible genomic principles. Reducing the science to a simple diet based on the gene responsible for a disease ignores too many genetic and genomic facts.

One of the main facts that does not substantiate a diet for a disease is that for so many diseases, there are multiple genes. Which gene will the diet be directed at? What happens when several environmental factors assault the individual? Will the individual recognize the relevant environmental factors in time to adjust the diet? How frequently will one need to adjust the diet to accommodate environmental changes? I understand that it is quite easy to entice someone to buy into nutrigenetics testing. We are all striving for long life and perfect health without much fussing and little interference to important things that we have to do. What would be less satisfying as eating for fitness? We could extrapolate to where an individual receive your pre-programmed diet soon after birth. It would then require little thinking from day to day. One would robot-like reach into the cupboard for some freeze dried meal or perhaps have it condensed into pills that one just pops two or three times per day.

Besides being awfully boring, I would think it would be outdated repeatedly, either by other gene expressions, new environmental exposure or synergistic effect from other diseases and stress.

Petrona Lee

Landmark Study Identifies A Large Number Of New Proteins Implicated In Huntington's Disease

Researchers from four organizations have identified more than 200 new proteins that bind to normal and mutant forms of the protein that causes Huntington's disease (HD). HD is a fatal inherited disease that affects 30,000 Americans annually by laying waste to their nervous system.

The research was led by Buck Institute faculty member Robert E. Hughes, PhD. Results of the study, which may facilitate the discovery of an effective treatment for HD, will be published in the May 11 edition of PLoS Genetics, an online, open-source journal, enabling scientists from around the world to take advantage of the findings immediately.

The work, which involved high-tech screening of the human genome and proteome, was unprecedented both in terms of its scale and in the way the protein interactions were validated in a genetic model of the disease. By conducting additional experiments in fruit flies genetically altered to express features of human HD, scientists showed that changing the expression of these interacting proteins affected the degree of damage seen in the fly neurons. This indicates that a significant number of the proteins might be potential drug targets for HD.

Now that researchers have discovered the interacting proteins using human libraries and human protein extracts and tested them in the fly, Hughes says the next step is to bring the research back into the mammalian world. The new genes and proteins discovered in this study are being screened and analyzed in cultured mammalian cells; the ones that show activity in ongoing experiments will be tested in mouse models of HD.

"Here at the Buck Institute, we're going to be focusing on a few dozen proteins," said Hughes. "Effective follow-up on any target protein depends, in large part, on how much expertise a scientist has with that target. We are hoping that researchers will look at this study and that those with specific expertise in a particular protein will move forward with their own inquiries."

The work was supported by HD advocacy organizations. "We are very excited about this significant discovery," said Allan Tobin, PhD, Senior Scientific Advisor to the High Q Foundation and CHDI, Inc. "This work helps define and refine possible therapeutic targets for a disease that lacks thorough understanding." Tobin added, "We are pleased this study is being published in an open-access journal, which makes it easier for scientists at other organizations to get to work on following up on this landmark discovery." Traditional peer-reviewed journals usually require scientists to pay a fee to access study results.

Tobin added that the need for further scientific inquiry is urgent. There is currently no effective treatment or cure for HD, which is typically characterized by involuntary movements and dementia. The disease slowly diminishes a person's ability to move, think and communicate. Those affected eventually become totally dependent on others for their care and usually die from complications such as choking, heart failure or infection. The disease is hereditary; each child of a person with HD has a 50/50 chance of inheriting the fatal gene. Approximately 200,000 Americans are believed to be at risk of developing HD, a disease that affects as many people as hemophilia, cystic fibrosis or muscular dystrophy. The symptoms of HD typically begin to appear in mid-life, although the progression of the disease varies among individuals and within the same family.

Joining Hughes as co-authors of the paper are Buck Institute scientists Cameron Torcassi, and Lisa Ellerby; along with Eliana Romano and Juan Botas from the Baylor College of Medicine in Houston; Andrew Strand, and James Olson from the Fred Hutchinson Cancer Research Center in Seattle; and Linda Kaltenbach, Sudhir Sahasrabudhe, Cornelia Kurschner, and John M. Peltier of Prolexys Pharmaceuticals in Salt Lake City. The work was supported by grants from the HighQ Foundation, CCHI Inc, the Hereditary Disease Foundation and National Institutes of Health.

The Buck Institute is an independent non-profit organization dedicated to extending the healthspan, the healthy years of each individual's life. The National Institute of Aging designated the Buck a Nathan Shock Center of Excellence in the Biology of Aging, one of just five centers in the country. Buck Institute scientists work in an innovative, interdisciplinary setting to understand the mechanisms of aging and to discover new ways of detecting, preventing and treating age-related diseases such as Alzheimer's and Parkinson's disease, cancer, stroke, and arthritis. Collaborative research at the Institute is supported by genomics, proteomics and bioinformatics technology.


APHA Genomics Forum is forming

A forum dedicated to the role of genomics in public health is being formed within the APHA. Member recruitment is currently ongoing. You don't have to be a member of the APHA to join.

From the APHA Genomics Forum website:

What is the Genomics Forum?

The proposed Genomics Forum of APHA is a growing, interdisciplinary group of individuals, focused on different aspects of public health. We realize the growing influence that genetics and genomics are exerting upon everyday life in America and the need for APHA to play a key role in deciding how they will be used to affect the health of populations.

The predictive nature of genetics/genomics parallels the preventive health goals of public health agencies throughout the nation. However, most public health agencies are not aware of how genetics/genomics can be used as a tool to improve population health. There is a great need to educate the current and future public health workforce to understand the basics of genetics/genomics and the implications of this field, provide communities with appropriately designed information that will promote good health in the context of genetic information, and make sure that genetic information is used to decrease and not increase health disparities of all types (income, education, ethnicity, etc.). The proposed forum will focus on this integration of genomics into public health.

This forum will also allow APHA to show a firm commitment to assuring that public health principles are integrated into genomics practice and research. For example, multiple government agencies are placing substantial funds into clinical applications such as pharmacogenomics (i.e. personalized medicine). In order to make sure that personalized medicine means public medicine, APHA must be at the forefront of conversations about how genetics/genomics will be used to improve the health of people in America and worldwide. This forum will contribute to ensuring that this happens.

Get more information here.

Genome Researchers Find New Indicators of Breast Cancer Risk

Nicholas Wade reports in The New York Times today that scientists may be close to the end of the discovery phase in the quest for finding and characterizing genomic elements important in the etiology of breast cancer. These discoveries are the result of applying whole gene association analytical techniques to the problem.

Together with already known genes, the discovery means that a sizable fraction of the overall genetic risk of breast cancer may now have been accounted for, researchers say, and much of the rest could be captured in a few years.

The findings do not point to any new treatment and are too little understood to serve as the basis of a diagnostic test. But they are a critical step toward understanding the biology of breast cancer, scientists say, from which new treatments should emerge.

This last is especially important. Understanding the biology of breast cancer and other chronic diseases is likely the most important outcome of the Human Genome Project and will almost certainly have the greatest impact on prevention and treatment of this common condition. However, in the meantime, there may be opportunities to develop tools to help identify which women are at increased risk:

A team lead by Simon N. Stacey of DeCode Genetics reports that 25 percent of women of European descent carry one copy of a DNA variant on the second of the 23 human chromosomes, conferring a 44 percent greater risk of breast cancer than for women without it, and that 7 percent of women have inherited two copies, with a 64 percent greater risk.

However, not everybody is as enthusiastic about the implications of this new discovery. Mary Claire King, a researcher who was instrumental in discovering the first major gene associated with a predisposition for breast and ovarian cancer, BRCA1, comments:

Mary-Claire King, a biologist at the University of Washington in Seattle who pioneered the search for the BRCA1 cancer gene, criticized the statistical basis of the studies and suggested they should not have been published until the biological significance of the suspect sites had been established.

“I believe the motivation to publish based on so little biological or genetic evidence,? Dr. King said, “is that an enormous amount of money has been put into these efforts and hence the need to see positive results is huge.?

Dr. King’s principal criticism of the statistics of the three studies is that when 500,000 sites of variation are tested all at once for association with disease, many may come out positive just by chance, not because of any real link.

This will be a very interesting area to watch for further developments in the near future. The original reports are published online in Nature Genetics. You can read more about this here and here.

May 27, 2007

Testing for susceptibility to Type 2 Diabetes: Ready for prime time?

DNA Direct and deCODE Genetics are teaming up to offer a test for the polymorphism in the TCF7L2 gene that is associated with an increased risk for developing diabetes. Check out the story and commentary on Hsien Hsien Lei's Genetics and Health blog here

The discovery of the association between a common polymorphism in the TCF7L2 gene and risk for diabetes was first published in Nature Genetics by the deCode Genetics group a little over a year ago in March 2006. Link to the PubMed abstract here.

Since this report was published, the scramble to replicate these findings in other populations has been going on at a furious pace. A PubMed search using the terms "TCF7L2 Diabetes" came up with 44 published reports in just over a year.

In a nutshell, the association between the “T? allele of SNP rs7903146 in the TCF7L2 gene is being being replicated by different labs and different populations all over the world and is now being offered as a susceptibility test directly to consumers without the mediation of a health care provider. Is this a good idea? Count me amongst the skeptical on this one.