Showing posts with label finds. Show all posts
Showing posts with label finds. Show all posts

Tuesday, 25 October 2011

Exceptional cognitive and physical health in old age leaves immunological fingerprint, study finds

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ScienceDaily (Oct. 21, 2011) — Exceptional cognitive and physical function in old age leaves a tell-tale immunologic fingerprint, say researchers at the University of Pittsburgh and Children's Hospital of Pittsburgh of UPMC. Likewise, older adults who have mild impairments bear a distinct immunologic pattern, too, according to findings appearing in the online journal PLoS ONE, published by the Public Library of Science.

Old age is not synonymous with impairment and disability, noted lead investigator Abbe N. de Vallejo, Ph.D., associate professor of pediatrics and immunology, University of Pittsburgh School of Medicine.

"Our study indicates that getting older does not necessarily mean that the immune system gets weaker, as many of us assumed," he said. "The immune system is dynamic, and the changes it undergoes over time very much influence function."

For the project, the team collected blood samples from 140 participants who had been followed in the Cardiovascular Health Study (CHS) for nearly two decades and were 78 to 94 years old. With only two participants younger than 82, the average age of the group was 86. The team also gathered information about the participants' health and function, medical history and hospitalizations, and self-rated health, and assessed their cognitive and physical function using standard tests.

Previous research has shown that with age, immune cells called T-cells become more like natural killer (NK) cells, which typically target tumor cells and virus-infected cells, Dr. de Vallejo said. A closer look in the new study shows that participants who were most physically and cognitively resilient had a dominant pattern of stimulatory NK receptors on the T-cell surface, and that these unusual T-cells can be activated directly through these NK receptors independently of the conventional ones. The functionally resilient elders also have a distinct profile of blood proteins called cytokines that reflect an immune-enhancing environment.

Conversely, the group that showed mild health impairment had a dominant pattern of inhibitory NK receptors on their T-cells, and they have a cytokine profile indicating a pro-inflammatory environment. Both of these immunologic features could suggest a greater susceptibility to illness.

"These findings indicate that there is remodeling or adaptation of the immune system as we age that can be either protective or detrimental," Dr. de Vallejo said. "Now we have an immunological fingerprint that can identify individuals who are more likely to stay physically and cognitively well."

He and his colleagues are now studying factors, such as genetics or traits developed during childhood that might influence the adaptation of the immune system with advancing age.

The team includes Anne B. Newman, M.D., professor and chair, Department of Epidemiology, University of Pittsburgh Graduate School of Public Health (GSPH), and director of the Center for Aging and Population Health, as well as others from GSPH and the Pitt School of Medicine. The study was funded by the National Institutes of Health.

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The above story is reprinted from materials provided by University of Pittsburgh Schools of the Health Sciences.

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Journal Reference:

Abbe N. Vallejo, David L. Hamel, Robert G. Mueller, Diane G. Ives, Joshua J. Michel, Robert M. Boudreau, Anne B. Newman. NK-Like T Cells and Plasma Cytokines, but Not Anti-Viral Serology, Define Immune Fingerprints of Resilience and Mild Disability in Exceptional Aging. PLoS ONE, 2011; 6 (10): e26558 DOI: 10.1371/journal.pone.0026558

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Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment. Views expressed here do not necessarily reflect those of ScienceDaily or its staff.


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Elevated hormone levels add up to increased breast cancer risk, research finds

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ScienceDaily (Oct. 21, 2011) — Post-menopausal women with high levels of hormones such as estrogen or testosterone are known to have a higher risk of breast cancer. New research published in BioMed Central's open access journal Breast Cancer Research looked at eight different sex and growth hormones and found that the risk of breast cancer increased with the number of elevated hormones -- each additional elevated hormone level increased risk by 16%.

Researchers from the Brigham and Women's Hospital and Harvard Medical School used blood samples collected from nurses up to nine years before health information, including their breast cancer status, was recorded. Post-menopausal women who were diagnosed with breast cancer were matched to two controls of a similar age.

The highest levels of circulating estrogens (estrone and estrogen), prolactin, and androgens (testosterone, androstenedione, DHEA, or DHEA-sulfate) were individually associated with between 50 and 200% increase in breast cancer risk. The number of different hormones elevated above normal further increased risk, so that women with one elevated hormone had an increased risk of 10% (compared to normal levels), but the risk for women with five or six elevated hormone levels was doubled, and that for women with seven or eight was tripled. All these risks were slightly higher for women with ER positive disease.

Dr Shelley Tworoger, from Brigham and Women's Hospital, commented that "Elevated estrogens had the biggest effect on risk, especially for ER positive cancer. However, androgens, and prolactin also contribute to increasing risk of breast cancer. These hormones are known to stimulate the growth of breast cancer cells in the lab and, while androgens can be converted to estrogen in the body, these hormones have also been found to stimulate cancer cell growth in the absence of ER. Our results suggest that models used to assess breast cancer risk could be improved by taking into account multiple sex hormone and growth hormone levels."

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Journal Reference:

Shelley S Tworoger, Bernard A Rosner, Walter C Willett and Susan E Hankinson. The combined influence of multiple sex and growth hormones on risk of postmenopausal breast cancer: a nested case-control study. Breast Cancer Research, 2011; 13: R99 DOI: 10.1186/bcr3040

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Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment. Views expressed here do not necessarily reflect those of ScienceDaily or its staff.


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