Cholesterol-lowering drugs and the risk of hemorrhagic stroke

Contact: Angela Babb
ababb@aan.com
651-695-2789
American Academy of Neurology

ST. PAUL, Minn. – People taking cholesterol-lowering drugs such as atorvastatin after a stroke may be at an increased risk of hemorrhagic stroke, or bleeding in the brain, a risk not found in patients taking statins who have never had a stroke. But researchers caution the risk must be balanced against the much larger overall benefit of the statin in reducing the total risk of a second stroke and other cardiovascular events when making treatment decisions. The research is published in the December 12, 2007, online issue of Neurology®, the medical journal of the American Academy of Neurology.

For the study, researchers conducted a secondary analysis of the results of the Stroke Prevention with Aggressive Reduction in Cholesterol Levels (SPARCL) clinical trial. The trial enrolled 4,731 people who were within one to six months of having had a stroke or transient ischemic attack, or mini-stroke, and with no history of heart disease. Half of the participants received atorvastatin and half received a placebo. The participants were then followed for an average of four and a half years.

Overall, treatment was associated with a 16-percent reduction in total stroke, the study’s primary endpoint, as well as significant reductions in coronary heart events. However, secondary analysis found that the overall reduction in stroke included an increase in the risk of brain hemorrhage. Of those people randomized to atorvastatin, the study found 2.3 percent experienced a hemorrhagic stroke during the study compared to 1.4 percent of those taking placebo. The study also found there was a 21-percent reduction in ischemic stroke, a more common type of stroke involving a block in the blood supply to the brain, among people taking atorvastatin.

Other factors were also found to increase the risk of brain hemorrhage. For example, those who had experienced a hemorrhagic stroke prior to the study were more than five times as likely to suffer a second stroke of this kind. Men were also nearly twice as likely as women to suffer a hemorrhagic stroke. People with severe high blood pressure at their last doctor’s visit prior to the hemorrhagic stroke had over six times the risk of those with normal blood pressure.

“Although treatment of patients with a stroke or transient ischemic attack was clearly associated with an overall reduction in a second stroke, hemorrhagic stroke was more frequent in people treated with atorvastatin, in those with a prior hemorrhagic stroke, in men and in those with uncontrolled hypertension,” according to study author Larry B. Goldstein, MD, with Duke University Medical Center in Durham, North Carolina, and Fellow of the American Academy of Neurology. “This risk of hemorrhagic stroke also increased with age.”

“Treatment with atorvastatin did not disproportionately increase the frequency of brain hemorrhage associated with these other factors. The risk of hemorrhage in patients who have had a transient ischemic attack or stroke must be balanced against the benefits of cholesterol-lowering drugs in reducing the overall risk of a second stroke, as well as other cardiovascular events,” said Goldstein.

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The SPARCL trial was funded by Pfizer, the maker of atorvastatin.

The American Academy of Neurology, an association of more than 20,000 neurologists and neuroscience professionals, is dedicated to improving patient care through education and research. A neurologist is a doctor with specialized training in diagnosing, treating and managing disorders of the brain and nervous system such as stroke, Alzheimer’s disease, epilepsy, Parkinson disease, and multiple sclerosis.

For more information about the American Academy of Neurology, visit http://www.aan.com.

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European heat waves double in length since 1880

The most accurate measures of European daily temperatures ever indicate that the length of heat waves on the continent has doubled and the frequency of extremely hot days has nearly tripled in the past century. The new data shows that many previous assessments of daily summer temperature change underestimated heat wave events in western Europe by approximately 30 percent.

Paul Della-Marta and a team of researchers at the University of Bern in Switzerland compiled evidence from 54 high-quality recording locations from Sweden to Croatia and report that heat waves last an average of 3 days now—with some lasting up to 4.5 days—compared to an average of around 1.5 days in 1880. The results are published 3 August in the Journal of Geophysical Research-Atmospheres, a publication of the American Geophysical Union. The researchers suggest that their conclusions contribute to growing evidence that western Europe’s climate has become more extreme and confirm a previously hypothesized increase in the variance of daily summer temperatures since the 19th century.

The study adds evidence that heat waves, such as the devastating 2003 event in western Europe, are a likely sign of global warming; one that perhaps began as early as the 1950s, when their study showed some of the highest trends in summer mean temperature and summer temperature variance.

“These results add more evidence to the belief among climate scientists that western Europe will experience some of the highest environmental and social impacts of climate change and continue to experience devastating hot summers like the summer of 2003 more frequently in the future,” Della-Marta said.

The authors note that temperature records were likely overestimated in the past, when thermometers were not kept in modern Stevenson screens, which are instrument shelters used to protect temperature sensors from outside influences that could alter its readings. The researchers corrected for this warm bias and other biases in the variability of daily summer temperatures and show that nearly 40 percent of the changes in the frequency of hot days are likely to be caused by increases in summer temperatures’ variability. This finding demonstrates that even a small change in the variance of daily summer temperatures can radically enhance the number of extremely hot days.

“These findings provide observational support to climate modeling studies showing that European summer temperatures are particularly sensitive to global warming,” Della-Marta said. “Due to complex reactions between the summer atmosphere and the land, the variability of summer temperatures is expected to [continue to] increase substantially by 2100.”

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The research was supported by the European Environment and Sustainable Development Program, the Swiss National Science Foundation and the National Center for Excellence in Climate Research (NCCR Climate).

Contact: Jonathan Lifland
jlifland@agu.org
202-777-7535
American Geophysical Union

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Identifying the mechanism behind a genetic susceptibility to type 2 diabetes

Type 2 diabetes is reaching epidemic proportions in the developed world. Determining if and how certain genes predispose individuals to type 2 diabetes is likely to lead to the development of new treatment strategies for individuals with the disease.

In a study appearing in the August issue of the Journal of Clinical Investigation Valeriya Lyssenko and colleagues from Lund University in Sweden show that certain variants of the gene TCF7L2 make individuals more susceptible to type 2 diabetes. The susceptibility variants were associated with increased expression of TCF7L2 in pancreatic islet cells and decreased islet cell secretion of insulin. Consistent with this, ectopic overexpression of TCF7L2 in human islet cells decreased insulin secretion in response to exposure to glucose. This study identifies TCF7L2 type 2 diabetes susceptibility variants and provides a mechanism by which these genetic variants might cause susceptibility to the disease. As discussed by the authors and in the accompanying commentary by Andrew Hattersley from Peninsula Medical School in the United Kingdom, future studies are likely to investigate the potential for manipulating the signaling pathways controlled by TCF7L2 for the development of new therapeutics for type 2 diabetes.

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TITLE: Mechanisms by which common variants in the TCF7L2 gene increase risk of type 2 diabetes

AUTHOR CONTACT:
Valeriya Lyssenko
Lund University, University Hospital Malma, Malma, Sweden.
Phone: 46-40-391214; Fax: 46-40-391222; E-mail: Valeri.Lyssenko@med.lu.se.

View the PDF of this article at: https://www.the-jci.org/article.php?id=30706

ACCOMPANYING COMMENTARY
TITLE: Prime suspect: the TCF7L2 gene and type 2 diabetes risk

AUTHOR CONTACT:
Andrew T. Hattersley
Institute of Biomedical and Clinical Sciences, Peninsula Medical School, Exeter, United Kingdom.
Phone: 44-1392-406806; Fax: 44-1392-406767; E-mail: Andrew.Hattersley@pms.ac.uk.

View the PDF of this article at: https://www.the-jci.org/article.php?id=33077

Contact: Karen Honey
press_releases@the-jci.org
215-573-1850
Journal of Clinical Investigation

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U-M researchers find family of ‘on switches’ that cause prostate cancer

Gene fusions trigger cancer growth, could impact treatment choices

ANN ARBOR, Mich. — Researchers at the University of Michigan Comprehensive Cancer Center have discovered how genes turn on the switch that leads to prostate cancer.

The team discovered that pieces of two chromosomes can trade places with each other and cause two genes to fuse together. The fused genes then override the “off” switch that keeps cells from growing uncontrollably, causing prostate cancer to develop.

By testing these gene fusions in mice and in cell cultures, the researchers showed that the fusions are what cause prostate cancer to develop. But it’s not just one set of genes that fuse. The researchers found that any one of several in a family of genes can become scrambled and fuse. Results of the study appear in the Aug. 2 issue of Nature.

“Each of these switches, or gene fusions, represent different molecular subtypes. This tells us there’s not just one type of prostate cancer. It’s a more complex disease and potentially needs to be treated differently in each patient,” says lead study author Arul Chinnaiyan, M.D., Ph.D., director of the Michigan Center for Translational Pathology, a new U-M center whose goal is to translate research into real world practice.

The gene fusion research is the centerpiece project of the new center. In the current study, researchers found one of several abnormal gene fusions in the prostate cancer tissue samples they tested. In 2005, the researchers identified a prostate-specific gene called TMPRSS2, which fuses with either ERG or ETV1, two genes known to be involved in several types of cancer.

The Nature paper reports on five additional genes that fuse with ERG or ETV1 to cause prostate cancer. Gene fusions were involved in 60 percent to 70 percent of the prostate cancer cell lines the researchers looked at. The genes involved are all controlled by a different mechanism. For example, four of the genes are regulated by androgen, a male sex hormone known to fuel prostate cancer. Androgen deprivation is a common therapy for prostate cancer.

Knowing which gene fusion is involved in an individual patient’s tumor could impact treatment options. If an androgen-regulated gene is involved, androgen therapy would be appropriate. But if the gene fusion involves a gene that represses androgen, the anti-androgen therapy could encourage the cancer’s growth. This may also explain why androgen treatment is not effective for some prostate cancers.

“Typing someone’s prostate cancer by gene fusion can affect the treatment given. We would not want to give androgen to someone whose prostate cancer gene fusion is not regulated by androgen,” says Chinnaiyan, who is the S.P. Hicks Collegiate Professor of Pathology at the U-M Medical School.

Rearrangements in chromosomes and fused genes are known to play a role in blood cell cancers like leukemia and lymphoma, and in Ewing’s sarcoma. A fused gene combination that plays a role in chronic myelogenous leukemia led researchers to develop the drug Gleevec, which has dramatically improved survival rates for that disease.

Chinnaiyan believes the prostate gene fusions will eventually lead to similar treatments for prostate cancer.

“More immediately, we hope to develop tests for diagnosis or prognosis. But long-term, we hope this will lead to better therapies to treat prostate cancer. The key challenge is to find a drug that would go after this gene fusion,” Chinnaiyan says.

The gene fusion technology has been licensed to San Diego-based Gen-Probe Inc., which is working on a screening tool to detect gene fusions in urine. The tool could one day supplement or replace the prostate specific antigen, or PSA, test currently used to screen for prostate cancer.

The idea of translating laboratory research findings into a test or treatment that will impact patients is central to the new Michigan Center for Translational Pathology. The center brings together experts in genomics, proteomics and bioinformatics to look at common patterns and potential targets in cancer and other diseases. This is the first center of its kind in the nation in that it is associated with one of 39 National Cancer Institute-designated “comprehensive” cancer centers, a premier medical school and a large health system with both clinicians and patients.

The center’s goal is to study the genes, proteins and other markers on cells to develop new diagnostic tests or screening tools as well as targeted treatments for cancer and other diseases, with the key being to translate these laboratory discoveries into clinical applications.

Chinnaiyan and his team have received numerous awards and honors, including the American Association for Cancer Research Team Science Award for their previously published work on gene fusions, and the Specialized Program of Research Excellence Outstanding Investigator award. The new Center for Translational Pathology supported in part by the Prostate Cancer Foundation, which has offered to match up to $1 million dollars in donations to support work related to developing therapies against prostate cancer gene fusions at the university.

“Mapping of the human genome was only the beginning. Equipped with the comprehensive analysis of the human genome, we can now systematically examine the blueprint of disease at the molecular level. This essential knowledge may lead to better diagnostic tests and promising new treatments for cancer, cardiovascular disease, diabetes and other illnesses,” Chinnaiyan says.

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For information about the Michigan Center for Translational Pathology, go to http://www.med.umich.edu/mctp.

About 218,890 men will be diagnosed with prostate cancer this year, and 27,050 will die from the disease, according to the American Cancer Society. The gene fusion work is not currently available for treatment or diagnosis, and no clinical trials are currently recruiting. For information about prostate cancer and currently available treatments, go to http://www.mcancer.org or call the U-M Cancer AnswerLine at 800-865-1125.

In addition to Chinnaiyan, U-M study authors were Scott Tomlins; Saravana Dhanasekaran, Ph.D.; Bharathi Laxman; Qi Cao; Beth Helgeson; Xuhong Cao; David Morris, M.D.; Anjana Menon; Xiaojun Jing; Bo Han; James Montie, M.D.; Kenneth Pienta, M.D.; Diane Roulston; Rajal Shah, M.D.; Sooryanarayana Varambally, Ph.D.; and Rohit Mehra, M.D. Mark Rubin, M.D., from Brigham and Women’s Hospital, Dana-Farber Cancer Institute and Harvard Medical School is also a study author.

Funding for the study came from the U.S. Department of Defense, the National Institutes of Health, the Early Detection Research Network, the Prostate Cancer Foundation and Gen-Probe Inc.

The University of Michigan has filed for a patent on the detection of gene fusions in prostate cancer, on which Tomlins, Mehra, Rubin and Chinnaiyan are co-inventors. The diagnostic field of use has been licensed to Gen-Probe Inc. Chinnaiyan also has a sponsored research agreement with Gen-Probe; however, GenProbe has had no role in the design or experimentation of this study, nor has it participated in the writing of the manuscript.

Reference: Nature, Vol. 448, No. 7153, Aug. 2, 2007

Contact: Nicole Fawcett
nfawcett@umich.edu
734-764-2220
University of Michigan Health System

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Huntington’s disease study shows animal models on target

This release is available in French.

An international team of researchers has published a benchmark study showing that gene expression in several animal models of Huntington’s Disease (HD) closely resembles that of human HD patients.

The results, published August 1, 2007, in the , validate the applicability of using animal models to study human disease and will have important consequences for the pertinence of these models in preclinical drug testing.

Huntington’s disease is an incurable and fatal hereditary neurodegenerative disorder caused by a mutation in the gene that encodes the huntingtin protein. Neurons in certain regions of the brain succumb to the effects of the altered protein, leading to severe motor, psychiatric, and cognitive decline. Several recent studies have shown that the mutant huntingtin protein modifies the transcriptional activity of genes in affected neurons. This disease mechanism is a promising new avenue for research into the causes of neuronal death and a novel potential approach for treatment.

Led by EPFL professor Ruth Luthi-Carter, and involving collaborators from six countries, the current study found a marked resemblance between the molecular etiology of neurons in animal models and neurons in patients with HD. This implies that animal models are relevant for studying human HD and testing potential treatments.

To come to this conclusion, the scientists measured the gene expression profile of seven different transgenic mouse models of HD, representing different conditions and disease stages. These profiles clarified the role of different forms and dosages of the protein hungtintin in the transcriptional activity of neurons. They then designed and implemented novel computational methods for quantifying similarities between RNA profiles that would allow for comparisons between the gene expression in mice and in human patients. “Interestingly, results of different testing strategies converged to show that several available models accurately recapitulate the molecular changes observed in human HD,” explains Luthi-Carter. “It underlines the suitability of these animal models for preclinical testing of drugs that affect gene transcription in Huntington’s Disease.”

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More Information:

EPFL Laboratory of functional neurogenomics, http://lngf.epfl.ch/

Alexandre Kuhn ; +41 21 693 1731
alexandre.kuhn@epfl.ch

Professor Ruth Luthi-Carter; +41 21 693 9533
ruth.luthi-carter@epfl.ch

Contact: Alexandre Kuhn
alexandre.kuhn@epfl.ch
41-216-931-731
Ecole Polytechnique Fédérale de Lausanne

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Flip of genetic switch causes cancers in mice to self-destruct, Stanford researchers find

STANFORD, Calif. – Killing cancerous tumors isn’t easy, as anyone who has suffered through chemotherapy can attest. But a new study in mice shows that switching off a single malfunctioning gene can halt the limitless division of tumor cells and turn them back to the path of their own planned obsolescence.

The surprising possibility that a cell’s own natural mechanism for ensuring its mortality could be used to vanquish tumors opens the door to a new approach to developing drugs to treat cancer patients, according to Dean Felsher, MD, PhD, associate professor of medicine (oncology) and of pathology at the Stanford University School of Medicine. Felsher is the senior author of the study to be published July 30 in the advance online version of the Proceedings of the National Academy of Sciences.

“Our research implies that by shutting off a critical cancer gene, tumor cells can realize that they are broken and restore this physiologic fail-safe program,” said Felsher.

Cancer can be notoriously resistant to medical treatment. Not only do cancer cells proliferate uncontrollably, they somehow circumvent the mechanism that causes normal cells to die when they get old or malfunction. That makes cancer cells effectively immortal unless doctors manage to squelch them.

The gene Felsher’s team studied produces a protein called Myc (pronounced “mick”), which promotes cell division. A mutation of the gene causes cells to overproduce the protein, prompting perpetual cell division and tumor growth. By turning off the mutated gene, the researchers found that not only did uncontrolled cell division cease, but the cells also reactivated a normal physiological mechanism, called senescence, which makes it possible for a cell to eventually die.

“What was unexpected was just the fact that cancer cells had retained the ability to undergo senescence at all,” said Felsher. Cancer researchers had long thought the senescence process had to be irreversibly disrupted for a tumor to develop.

The researchers worked with a series of mice engineered to have Myc-triggered cancers of either the liver, blood or bones, along with a specially constructed version of the Myc gene that they could switch off by feeding the mice antibiotics. When the mice dined on doses of the drugs, invariably, the tumors ceased growing and then diminished, with some disappearing over the course of just a few days.

Although Felsher’s lab had previously shown that mouse tumors diminished and disappeared when Myc was switched off, they hadn’t been sure how the process actually worked. Historically, most research involving genetic methods of battling cancer cells has focused on reactivating genes called tumor-suppressor genes, which are generally overcome by a proliferating cancer. No one had explored the idea that senescence might play a key role in diminishing tumors.

Felsher described senescence as acting like a fail-safe mechanism to stop cancer. When a cell detects a deleterious mutation, it launches the senescence process, resulting in the permanent loss of the cell’s ability to proliferate, thus halting any cancer.

“In order to become tumor cells, those cells have to overcome senescence,” said Chi-Hwa Wu, PhD, postdoctoral researcher in Felsher’s lab and first author of the study. Wu had the inspiration to explore whether the sudden diminishment they had observed in the tumors might be due to the reactivation of some latent remnant of the trigger for senescence.

Through a series of experiments looking at enzymes associated with the senescence process, as well as some molecular markers, Wu confirmed her suspicion. And not only was senescence occurring in cells that had been thought to be incapable of it, the process was reactivated in all the different tumors they studied.

Consider it a cell version of the Jekyll-and-Hyde transformation. “It’s sort of like Mr. Hyde realizing that there’s something wrong with him and then being able to put himself back into his normal state as Dr. Jekyll,” Felsher said.

In addition to the deepened understanding of how the process of senescence works, Felsher and Wu see a lot of potential for new approaches to treating cancer, beyond the traditional tactic of trying to kill cancer cells directly. “This work implies that maybe part of the strategy should involve figuring out how to get the cancer cells to just be allowed to do what they originally wanted to do anyway, which is to not be proliferating endlessly and growing uncontrolled,” said Felsher.

The next step for the team is to see how well the approach works in human cancer cells. “And we’re also trying to figure out what the mechanism is,” Felsher said. “What are the molecular mechanisms of this, so that we can figure out how to better treat cancer””

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Other authors on the research paper are Jan van Riggelen, PhD, postdoctoral researcher; Alper Yetil, graduate student in cancer biology; Alice Fan, MD, instructor in medicine (oncology), and medical student Pavan Bachireddy.

The study was funded by the National Cancer Institute, the National Institutes of Health, the Leukemia and Lymphoma Society, the Burroughs Wellcome Fund, the Damon Runyon Lilly Clinical Investigator Award, the Lymphoma Research Foundation and the Howard Hughes Medical Institute.

Stanford University Medical Center integrates research, medical education and patient care at its three institutions – Stanford University School of Medicine, Stanford Hospital & Clinics and Lucile Packard Children’s Hospital at Stanford. For more information, please visit the Web site of the medical center’s Office of Communication & Public Affairs at http://mednews.stanford.edu.

Contact: Lou Bergeron
louisb3@stanford.edu
650-723-3900
Stanford University Medical Center

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New studies on goat milk show it is more beneficial to health than cow milk

-It helps to prevent diseases such as anaemia and bone demineralisation
-UGR researchers have carried out a comparative study on the properties of goat milk compared to those of cow milk. Rats with induced nutritional ferropenic anaemia have been used in the study
-Goat milk helps digestive and metabolic utilisation of minerals such as iron, calcium, phosphorus and magnesium
-Part of the results of this research have been published in the prestigious scientific journals International Dairy Journal and Journal Dairy Science

C@MPUS DIGITAL Research carried out at the Department of Physiology of the University of Granada has revealed that goat milk has more beneficial properties to health than cow milk. Among these properties it helps to prevent ferropenic anaemia (iron deficiency) and bone demineralisation (softening of the bones).

This project, conducted by Doctor Javier Díaz Castro and directed by professors Margarita Sánchez Campos, Mª Inmaculada López Aliaga and Mª José Muñoz Alférez, focuses on the comparison between the nutritional properties of goat milk and cow milk, both with normal calcium content and calcium enriched, against the bioavailability of iron, calcium, phosphorus and magnesium. To carry out this study, the metabolic balance technique has been used both in rats with experimentally induced nutritional ferropenic anaemia and in a control group of rats.

In order to know how the nutritive utilisation of these minerals may affect their metabolic distribution and destination, the UGR researcher has determined the concentration of these minerals in the different organs involved in their homeostatic regulation and different haematological parameters in relation to the metabolism of the minerals.

Better results with goat milk
Results obtained in the study reveal that ferropenic anaemia and bone demineralisation caused by this pathology have a better recovery with goat milk. Due to the higher bioavailability of iron, calcium, phosphorus and magnesium, the restoration of altered haematological parameters and the better levels of parathyroid hormone (PTH), a hormone that regulates the calcium balance in the organism was found in the rats that consumed this food.

Javier Díaz Castro points out that the inclusion of goat milk with normal or double calcium content in the diet “favours digestive and metabolic utilisation of iron, calcium and phosphorus and their deposit in target organs – parts of the organism to which these minerals are preferably sent – involved in their homeostatic regulation”.

According to this researcher, all these conclusions reveal that regular consumption of goat milk – a natural food with highly beneficial nutritional characteristics – “has positive effects on mineral metabolism, recovery from ferropenic anaemia and bone mineralisation in rats. In addition, and unlike observations in cow milk, its calcium enrichment does not interfere in the bioavailability of the minerals studied”.

Although there is no doubt that these findings may be a base for further in depth study of the multiple health benefits of goat milk, the UGR researcher warns that “studies in humans are still required in order to confirm the findings obtained in rats and to promote goat milk consumption both in the general population and in the population affected by nutritional ferropenic anaemia and pathologies related to bone demineralisation”. Part of the results of this research has been published in the prestigious scientific journals International Dairy Journal and Journal Dairy Science.

Reference: Dr Javier Díaz Castro. Department of Physiology of the University of Granada.
Tel.: +34 958248319. Mobile: +34 654574434. Email: javierdc@ugr.es

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Research links genetic mutations to lupus

WINSTON-SALEM, N.C. – A gene discovered by scientists at Wake Forest University School of Medicine has been linked to lupus and related autoimmune diseases. The finding, reported in the current issue of Nature Genetics, is the latest in a series of revelations that shed new light on what goes wrong in human cells to cause the diseases.

“This research is a huge leap toward understanding the cause of lupus and related autoimmune diseases,” said Fred Perrino, Ph.D., a co-author on the paper and a professor of biochemistry at Wake Forest. “There had been few clues before now.”

Perrino, who discovered the gene in 1998, said he suspected it was involved in human disease, but it took a group of researchers from around the world collaborating to put the puzzle together.

“We’ve known that lupus was a complex disease, but now we have a specific protein and a particular cellular process that appears to be one of the causes,” said Perrino. “We’re connecting the dots to understand the biology of what’s going on with the disease.”

In Nature Genetics, lead author Min Ae Lee-Kirsch, M.D., from the Technische Universität Dresden in Dresden, Germany, and colleagues report finding variations of the TREX1 gene discovered by Perrino in patients with systemic lupus erythematosus. The study involved 417 lupus patients from the United Kingdom and Germany. Mutations were found in nine patients with lupus and were absent in 1,712 people without lupus.

“Our data identify a stronger risk for developing lupus in patients that carry variants of the gene,” said Lee-Kirsch.

In recent years, the gene was also linked to Aicardi-Goutieres syndrome, a rare neurological disease that causes death in infants, and to chilblain lupus, an inherited disease associated with painful bluish-red skin lesions that occur during cold weather and usually improve in summer. The current research also links it to Sjogren’s syndrome, a form of lupus.

The diseases are all autoimmuine diseases, which means that the body makes antibodies against itself. In lupus, these antibodies cause pain and inflammation in various parts of the body, including the skin, joints, heart, lungs, blood, kidneys and brain. The disease is characterized by pain, heat, redness, swelling and loss of function.

Perrino began studying the protein made by the gene more than 14 years ago.

“We basically cracked open cells to locate the protein and find the gene,” said Perrino. “In the 14 years since, we’ve learned a lot about the protein and how it functions.”

The gene manufactures a protein, also known as TREX1, whose function is to “disassemble” or “unravel” DNA, the strand of genetic material that controls processes within cells. The “unraveling” occurs during the natural process of cells dying and being replaced by new cells. If a cell’s DNA isn’t degraded or unraveled during cell death, the body develops antibodies against it.

“If the TREX1 protein isn’t working to disassemble the DNA, you make antibodies to your own DNA and can end up with a disease like lupus,” said Perrino.

Perrino and colleagues at Wake Forest have been studying the gene and its protein since 1993. Thomas Hollis, Ph.D., an assistant professor of biochemistry at Wake Forest, is credited with solving the structure of both TREX1 and a similar protein, TREX2. Perrino has also developed a way to measure the function of the proteins.

In a study reported in April in the Journal of Biological Chemistry, Hollis and Perrino found that three variations of the gene reduced the activity of the protein by four- to 35,000-fold.

“Now that we have the structure, we can understand how it disassembles DNA and how mutations in the gene may affect that process,” said Hollis.

The researchers hope that understanding more about the gene’s mutations and the structure of the protein may lead to drug treatments to help ensure that mutant copies of the gene are inactive.

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Media Contacts: Karen Richardson, krchrdsn@wfubmc.edu; Shannon Koontz, shkoontz@wfubmc.edu; at 336-716-4587.

Wake Forest University Baptist Medical Center is an academic health system comprised of North Carolina Baptist Hospital and Wake Forest University Health Sciences, which operates the university’s School of Medicine. U.S. News & World Report ranks Wake Forest University School of Medicine 18th in primary care and 44th in research among the nation’s medical schools. It ranks 35th in research funding by the National Institutes of Health. Almost 150 members of the medical school faculty are listed in Best Doctors in America.

Contact: Karen Richardson
krchrdsn@wfubmc.edu
336-716-4453
Wake Forest University Baptist Medical Center

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Poor sleep associated with cognitive decline in elderly women

Disturbed sleep associated with decline in cognition over time; no link with total hours of sleep per night
Women who experienced cognitive decline over a 13 to 15 year period after age 65 were more likely to sleep poorly than women whose cognition did not decline, according to a study led by researchers at the San Francisco VA Medical Center (SFVAMC).

The women’s cognitive decline was associated with interrupted or fitful sleep. Total sleep time per night made no difference, says lead author Kristine Yaffe, MD, chief of geriatric psychiatry at SFVAMC and professor of psychiatry, neurology, epidemiology, and biostatistics at the University of California, San Francisco (UCSF).

“This indicates that it’s not how long you sleep, but how well you sleep,” she says.

The study appears in the July 17, 2007 issue of Neurology.

Yaffe speculates that there are three possible explanations for the association between cognitive decline and disturbed sleep. She says the first and most likely reason is that whatever neurodegenerative condition is starting to cause cognitive decline, such as Alzheimer’s disease, is also affecting areas of the brain that govern sleep.

“Sleep is very complex,” notes Yaffe. “It involves a coordinated series of neurologic functions that we don’t entirely understand. It’s not unlikely that early neurodegenerative disease could start having an effect on sleep centers as well.”

Another possibility is that someone who is becoming cognitively impaired is sleeping poorly “because they’re aware of their condition and they’re worried about it.”

Finally, Yaffe says that other factors entirely, such as brain inflammation or genetic changes, might cause both cognitive decline and sleep disturbance at the same time.

The researchers studied 2,474 women who were part of a larger ongoing prospective study of risk factors for osteoporosis that began in 1986. The mean age of the women was 68.9 years at the beginning of the study. Their cognitive health was measured at regular intervals over the course of the study using two standard cognitive tests: the Mini-Mental State Examination and the Trail Making Test, Part B, known as Trails B.

After 13 to 15 years in the study, the women were fitted with an actigraph, a small device worn on the wrist that measures movement and is known from previous studies to be highly accurate in differentiating sleep from wakefulness. The women wore the device for at least three consecutive 24-hour periods.

Women who performed progressively worse on both cognitive tests over time were significantly more likely to have difficulty falling asleep and staying asleep than women whose performance did not decline. Women who performed progressively worse on the Trails B test also napped significantly more during the day.

The association between cognitive decline and poor sleep remained even after the researchers adjusted for a host of other demographic factors such as age, education, depression, exercise, and health status.

“It’s been known for some time that people with cognitive problems often have sleep problems, but those studies have mostly been done on severely demented people in nursing homes,” observes Yaffe. “Ours was the first study to look at the relationship between sleep and cognition in healthy women dwelling in the community who did not have dementia to begin with.”

Yaffe offers several cautions concerning the results of the study. First, men and African-American women were excluded from the original osteoporosis study because both of those groups have low incidence of osteoporotic fractures. Additionally, sleep patterns were measured only once, “so it’s more of a snapshot.”

However, Yaffe says that the research group has received a grant from the National Institutes of Health to continue tracking sleep patterns and cognitive health over time in the same study cohort. “Hopefully, we’ll be able to tell if cognitive changes lead to sleep disturbances, or if the reverse is true, or if they have a common independent cause.”

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Co-authors of the paper were Terri Blackwell, MA, of the California Pacific Medical Center Research Institute (CPMCRI); Deborah E. Barnes, PhD, of SFVAMC and UCSF; Sonia Ancoli-Israel, PhD, of the University of California, San Diego and the VA San Diego Healthcare System; and Katie Stone, PhD, of CPMCRI, for the Study of Osteopororic Fractures Group.

The study was supported by grants from the National Institutes of Health and the National Institute on Aging.

SFVAMC has the largest medical research program in the national VA system, with more than 200 research scientists, all of whom are faculty members at UCSF.

UCSF is a leading university that advances health worldwide by conducting advanced biomedical research, educating graduate students in the life sciences and health professions, and providing complex patient care.

Contact: Steve Tokar
steve.tokar@ncire.org
415-221-4810 x5202
University of California – San Francisco

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One man’s junk may be a genomic treasure

Scientists have only recently begun to speculate that what’s referred to as “junk” DNA – the 96 percent of the human genome that doesn’t encode for proteins and previously seemed to have no useful purpose – is present in the genome for an important reason. But it wasn’t clear what the reason was. Now, researchers at the University of California, San Diego (UCSD) School of Medicine have discovered one important function of so-called junk DNA.

Genes, which make up about four percent of the genome, encode for proteins, “the building blocks of life.” An international collaboration of scientists led by Michael G. Rosenfeld, M.D., Howard Hughes Medical Investigator and UCSD professor of medicine, found that some of the remaining 96 percent of genomic material might be important in the formation of boundaries that help properly organize these building blocks. Their work will be published in the July 13 issue of the journal Science.

“Some of the ‘junk’ DNA might be considered ‘punctuation marks’ – commas and periods that help make sense of the coding portion of the genome,” said first author Victoria Lunyak, Ph.D., assistant research scientist at UCSD.

In mice, as in humans, only about 4 percent of the genome encodes for protein function; the remainder, or “junk” DNA, represents repetitive and non-coding sequences. The research team studied a repeated genomic sequence called SINE B2, which is located on the growth hormone gene locus, the gene related to the aging process and longevity. The scientists were surprised to find that SINE B2 sequence is critical to formation of the functional domain boundaries for this locus.

Functional domains are stretches of DNA within the genome that contain all the regulatory signals and other information necessary to activate or repress a particular gene. Each domain is an entity unto itself that is defined, or bracketed, by a boundary, much as words in a sentence are bracketed by punctuation marks. The researchers’ data suggest that repeated genomic sequences might be a widely used strategy used in mammals to organize functional domains.

“Without boundary elements, the coding portion of the genome is like a long, run-on sequence of words without punctuation,” said Rosenfeld.

Decoding the information written in “junk” DNA could open new areas of medical research, particularly in the area of gene therapy. Scientists may find that transferring encoding genes into a patient, without also transferring the surrounding genomic sequences which give structure or meaning to these genes, would render gene therapy ineffective.

Contributors to the paper include Lluis Montoliu, Rosa Roy and Angel Garcia-Díaz of the Department of Molecular and Cellular Biology, Centro Nacional de Biotecnología in Madrid, Spain; Christopher K. Glass, M.D., Ph.D., UCSD Department of Cellular and Molecular Medicine; Esperanza Núñez, Gratien G. Prefontaine, Bong-Gun Ju, Kenneth A. Ohgi, Kasey Hutt, Xiaoyan Zhu and Yun Yung, Howard Hughes Medical Institute, Department of Molecular Medicine, UCSD School of Medicine; and Thorsten Cramer, Division of Endocrinology, UCSD Department of Medicine.

The research was funded in part by the Howard Hughes Medical Institute and the National Institutes of Health.

Contact: Debra Kain
ddkain@ucsd.edu
619-543-6163
University of California – San Diego

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