I thought I'd pass on a collection of interesting items that caught my eye in the past couple of days; none are really worth long commentary in and of themselves, but consider them to be signs of the times. Most of the amazing things researchers now know and can accomplish with modern biotechnology go largely unremarked in a field of similar acheivements - progress measured as a glazing of the eyes in the face of a sea of advances in medicine.
Telomere length (TL) is emerging as a biomarker for aging and survival. To evaluate factors influencing this trait, we measured TL in a large homogeneous population, estimated the heritability (h^2), and tested for parental effects on TL variation. Our sample included 356 men and 551 women, aged 18-92 years, from large Amish families.
As expected, TL was negatively correlated with age (r = -0.40; P < 0.001). There was no significant difference in TL between men and women, consistent with our previous findings that Amish men lived as long as Amish women. There was a stronger and positive correlation and association between TL in the offspring and paternal TL (r = 0.46, P < 0.001; = 0.22, P = 0.006) than offspring and maternal TL (r = 0.18, P = 0.04; = -0.02, P = 0.4). Furthermore, we observed a positive correlation and association between daughter's TL and paternal lifespan (r = 0.20, P < 0.001; = 0.21, P = 0.04), but not between daughter's TL and maternal lifespan (r = -0.01, = 0.04; both P = not significant).
King's College London scientists compared key ageing DNA with the number of moles in a study of 1,800 twins. They found the more moles a person had, the more likely their DNA was to have the properties to fight off ageing. The study, in the Cancer Epidemiology Biomarkers and Prevention journal, contrasts with the link between a high mole-count and high skin cancer risk.
In the study, researchers found those with more than 100 moles had longer telomeres than those with fewer than 25. The difference between the two mole groups was equivalent to six to seven years of ageing.
Lead researcher Dr Veronique Bataille said: "The results of this study are very exciting as they show, for the first time, that moley people who have a slightly increased risk of melanoma may, on the other hand, have the benefit of a reduced rate of ageing. This could imply susceptibility to fewer age-related diseases such as heart disease or osteoporosis, for example. Further studies are needed to confirm these findings."
This second article is another good example of the tradeoff between senescence and cancer seen in many aspects of human biology, but especially the mechanisms relating to telomere length:
in genetically modified mice that did not express telomerase, stem cells lost their functionality and became unable to regenerate the damaged epithelial tissue. On the whole, these mice aged more rapidly than normal mice. But, there was a very interesting side effect: without telomerase, mice showed a marked cancer resistance. ... Further experiments on telomeres structure showed that every time the shortening process is altered, the result is either 'early aging and cancer resistance' (if shortening is boosted), or 'aging inhibition and more cancer occurrence' (if shortening is reduced)."
A new project to partially sequence the genomes of 100 people age 100 or older could shed light on the genetic variations that allow some people to stay healthy decades beyond the average life expectancy. Dubbed the Methuselah Project, the endeavor will serve as a test bed for a new approach to sequencing
The project follows the highly publicized release of the genome of James Watson, codiscoverer of the structure of DNA. ... Carried out by 454 as a demonstration of its sequencing technology, the landmark project costs about an order of magnitude less than a human genome sequenced with traditional technologies.
But the Methuselah effort will use a new, streamlined way of analyzing the genome by isolating and sequencing only the so-called coding regions of DNA. By focusing on this small portion of the genome--about 1 percent--scientists can sequence 100 genomes for the same price as sequencing Watson's entire genome.
“The idea of using ES cells to make blood cells we can transplant, neurons that we can transplant . . . (with) all of the techniques and technologies, we thought that we had to target the stem cell,” Dr. Bhatia said. “Now we have a new target. We can also target the niche.”
“So we now have a completely new way of controlling differentiation toward regenerative medicine.... It really opens a whole new paradigm.”
Commenting on the paper Wednesday, the head of the Stem Cell Network of Canada said the work points scientists to new pathways for producing large quantities of embryonic stem cells in the lab, and brings the notion of regenerative medicine closer to reality.
Dr. Bhatia believes the work may also have implications for research into cancer stem cells, which appear to give rise to at least some tumour types and are resistant to chemotherapy, theoretically allowing malignancies that seemed to be cured to recur at a later time.
Conventional wisdom suggests that cancer stem cells - which have been identified in a number of malignancies, including blood and colon cancer - quietly hide in their niches for a period of time, then begin churning out daughter cells like some unstoppable Xerox machine, “which really is what a tumour is,” he said.
Dr. Bhatia suggested it may not be the cancer stem cell itself that goes awry, but the cells that make up the niche where it lives - particularly since the niche cells pump out proteins to feed their parent and may give it chemical directions for what to do.
“Maybe the niche lets go of its control. You can imagine that controlling the niche might be another target or way of controlling tumour growth.”
Matters are moving rapidly, and the cost of research is falling precipitously. Low cost research means more research, and at the same time it is increasingly the case that new discoveries in cell biology have implications for cancer, stem cell research and many other fields - a good sign of progress. Researchers are down at the basement level of biochemistry, tracing the wiring, with ever more helpers and ever better tools.
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