Daily Archives: April 24, 2014

More than 400 mutations were found in the healthy white blood cells of a 115-year-old woman, according to a new study that may advance what is known about limits of the human life span.

Genetic mutations have been linked to diseases such as cancer, but these findings suggest that mutations in white blood cells are largely harmless over a lifetime, the researchers said.

Blood is continually replenished by hematopoietic (meaning "to make blood") stem cells that are inside the bone marrow and divide to produce different types of blood cells.

Cell division can lead to genetic mutations and hundreds of mutations have been found in patients with blood cancers. However, little was known about white blood cells and mutations.

The woman in the study - whose name was not revealed - was the oldest person in the world when she died in 2005. She is thought to be the oldest person ever to donate her body to science. The hundreds of mutations identified in her white blood cells appeared to be tolerated by the body and did not cause disease.

The researchers also found possible new insight into the limits of human longevity, according to the authors of the study published online April 23 in the journal Genome Research.

"To our great surprise we found that, at the time of her death, the peripheral blood was derived from only two active hematopoietic stem cells (in contrast to an estimated 1,300 simultaneously active stem cells), which were related to each other," lead author Dr. Henne Holstege said in a journal news release.

The researchers also found that the woman's white blood cells' telomeres were extremely short. Telomeres, which are at the ends of chromosomes and protect them from damage, get a bit shorter each time a cell divides.

"Because these blood cells had extremely short telomeres, we speculate that most hematopoietic stem cells may have died from 'stem cell exhaustion,' reaching the upper limit of stem cell divisions," Holstege said.

Further research is needed to learn whether such stem cell exhaustion is a cause of death in extremely old people.

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Scientists seek genetic clues to longevity from 115-year-old woman

WEDNESDAY, April 23, 2014 (HealthDay News) -- More than 400 mutations were found in the healthy white blood cells of a 115-year-old woman, according to a new study that may advance what is known about limits of the human life span.

Genetic mutations have been linked to diseases such as cancer, but these findings suggest that mutations in white blood cells are largely harmless over a lifetime, the researchers said.

Blood is continually replenished by hematopoietic (meaning "to make blood") stem cells that are inside the bone marrow and divide to produce different types of blood cells.

Cell division can lead to genetic mutations and hundreds of mutations have been found in patients with blood cancers. However, little was known about white blood cells and mutations.

The woman in the study was the oldest person in the world when she died in 2005. She is thought to be the oldest person ever to donate her body to science. The hundreds of mutations identified in her white blood cells appeared to be tolerated by the body and did not cause disease.

The researchers also found possible new insight into the limits of human longevity, according to the authors of the study published online April 23 in the journal Genome Research.

"To our great surprise we found that, at the time of her death, the peripheral blood was derived from only two active hematopoietic stem cells (in contrast to an estimated 1,300 simultaneously active stem cells), which were related to each other," lead author Dr. Henne Holstege said in a journal news release.

The researchers also found that the woman's white blood cells' telomeres were extremely short. Telomeres, which are at the ends of chromosomes and protect them from damage, get a bit shorter each time a cell divides.

"Because these blood cells had extremely short telomeres, we speculate that most hematopoietic stem cells may have died from 'stem cell exhaustion,' reaching the upper limit of stem cell divisions," Holstege said.

Further research is needed to learn whether such stem cell exhaustion is a cause of death in extremely old people.

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Scientists study gene clues from 115-year-old woman

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Newswise University of Rochester Professor of Biology Vera Gorbunova, whose innovative research on DNA repair and the aging process has been internationally recognized, has been awarded a $9.5 million grant from the National Institute on Aging to study longevity.

Vera Gorbunova will lead a five-year project, which includes colleagues at the University of Rochester, Harvard University and the Albert Einstein College of Medicine, to explore the factors responsible for longevity in various rodent species, with the goal of developing treatments to improve the aging process in people.

Professor Gorbunova has made tremendous strides with her research on the anti-cancer mechanisms of naked mole rats, said University President Joel Seligman. We are extremely proud that she will now build on this groundbreaking work by leading colleagues at Harvard University and the Albert Einstein College of Medicine to advance our understanding of problems associated with aging.

Researchers at the three locations will focus on rodents because they are genetically similar to humans and have a diverse range of lifespans. Mice and rats, for example, typically live two to four years, while naked mole rats, beavers, porcupines, and squirrels have lifespans in excess of 20 years. Naked mole rats, which have been known to live more than 30 years, are of special interest since they remain free of age-related problems and diseaseincluding canceruntil the very end of their lives.

As people age, they are more likely to come down with a variety of diseases, such as cancer, cardiovascular disease, and osteoporosis, said Gorbunova. By working together, researchers at the three institutions will be better equipped to make progress in countering age-related health problems in people.

The work done by Gorbunova and her research partner, biologist Andrei Seluanov, has largely focused on DNA repair and cancer-resistance in naked mole rats in order to better understand the mechanisms responsible for longevity. In papers published last year, they identified HMW-HA (high molecular weight hyaluronan) as the chemical that triggers the anti-cancer response in the naked mole rat and attributed the rodents longevity to a process that results in nearly-perfect protein synthesis.

As Gorbunova points out, the University will serve as an ideal center for the research project, given the advances already made by her lab and its catalog of tissue and cell samples from 18 rodent species.

In addition to her leadership role, Gorbunova will conduct research to identify the factors responsible for more efficient DNA repair in long-lived species. With a better understanding of DNA repair, it may be possible to modulate those factors to delay human aging. Also at the University of Rochester, Andrei Seluanov, an assistant professor of biology, will study the mechanisms of longevity and cancer resistance in naked mole rats.

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Biologist Vera Gorbunova to Lead $9.5 Million Multi-Institution Longevity Research Project