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Hourglass X

Posted Jun 09 2009 10:08pm

Welcome to the tenth edition of Hourglass, our blog carnival about the biology of aging. This month, the carnival has returned home to Ouroboros. In this issue, we have submissions from six bloggers, including a nice mix of veterans and new participants. Several of the posts are united by common themes: we have heavy representation from the neuroscience community, and multiple discussions of the clinical and social payoffs that are likely to result from progress in lifespan extension.

At psique (which hosted Hourglass IX ), Laura Kilarski describes an important, evolving online tool for biogerontologists: the Human Aging Genomics Resources:

As I was reading a paper earlier about chromosomal region 11.5p and its putative association with aging (Lescai et al, 2009) I came across an interesting sounding url, namely http://genomics.senescence.info. Turns out that the website is home to HAGR, an interdisciplinary project devoted to the genetic study of aging … GenAge constitutes a major part of the site, and is a manually curated database of genes which could possibly be associated with human aging, largely based on studies done on the usual suspects: Mr. Mouse, Drosophila, C. elegans, and yeast. … The AnAge database on the other hand contains entries for over 4000 animals and some basic life-span-related facts. … And then there’s the ‘Δ Project’, the aim of which is to figure out transcriptional differences between young and old organisms.

Laura describes HAGR in depth and also provides some of her own analysis of the available resources.

On another age-related subject, neurodegeneration, Laura discusses the potential value of regular brain scans for early ascertainment of diseases such as Parkinson’s. Free brain scans for all! It’s a moving piece, which underscores the human cost of neurodegenerative illness and describes the author’s personal reactions on the subject, while also addressing important clinical and scientific issues.

As we age, we all suffer from some level of neurodegeneration, though in most cases this falls below the threshold of a clinical pathology. Slow chronic change isn’t the only form of age-related brain damage: let’s not forget about strokes, which can wipe out otherwise healthy neurons in macroscopic regions of the brain. While the risk factors for stroke and neurodegeneration are distinct, therapies might ultimately be quite similar — since in both cases, the goal is to regrow neurons to replace those that have been lost. At Brain Stimulant, Mike tell us about a clinical trial that will use stem cells to treat stroke:

The company Reneuron has just recently gotten the go ahead to commence a new trial that will use stem cells to treat patients with stroke damage. The trial will use stem cells to replace missing brain matter in those who have had stroke brain trauma. They are injecting doses of approximately 20 million stem cells into the stroke patients brain. Interestingly these ReN001 stem cells will not require a patient to have immunosuppression therapy.

He goes on to discuss the future challenges posed by the prospect for brain engineering: precise cell delivery, control of axon sprouting and pathfinding, and the possibility of using non-invasive methods to encourage the growth of new cells.

Also coming from a neuroscience perspective, Christopher Harris of Best Before Yesterday writes about What we need to accelerate biomedical research and fight aging.

A few hundred years ago I could not have been born. I was massive – 5.5kg – and the birth eventually turned caesarean and took many long hours. I owe my life to medical science. One day, 11 years later, I was out biking and realized for the first time that the annihilation following my death would be infinite. Now, 25 years after my complicated birth, I think a lot about whether medical science, rejuvenation research of the SENS variety in particular, will save me a second time.

What do we need? According to Harris: (1) Safe and inexpensive brain surgery (to install devices that can manipulate the reward circuitry of the brain); (2) Widespread use of enhanced motivation through deep brain stimulation (specifically to encourage exercise and healthy living); and (3) Rewarding brain stimulation for research centers (to accelerate scientific progress).

One of my favorite new sites, the Science of Aging Timeline, has a new entry about the Sinclair lab’s discovery of sirtuin-activating compounds:

Working off a model of calorie restriction via sirtuins David Sinclair et al. worked to find molecules which could modulate sitruins activity, and thus longevity.

They accomplished this by screening a number of small molecule libraries, which included analogues of epsilon-acetyl lysine, NAD+, NAD+ precursors, nucleotides and purinergic ligands. Results from the screening where assayed against human SIRT1 to identify potential inhibitors, and the following molecules where found: Resveratrol, Butein, Piceatannol, Isoliquiritigenin, Fisetin, and Quercetin. Of all of these, resveratrol proved to be the most potent …

In the copious spare time left when he’s not working on the comprehensive history of biogerontology, timeline curator Paul House has started another ambitious project: a catalog of all the labs working on aging. It’s early days yet, and only a few labs are listed, but I’ve already seen Paul take one great idea (the timeline) from seed to oak, so I have every confidence that this page will grow substantially in the weeks and months to come. Those who are interested in having their labs listed on the page can send Paul an email.

Over at Fight Aging!, Reason continues excellent coverage of recent papers in biogerontology; I daresay that the detail of coverage on primary scientific literature has improved even further in the past month or so, concomitant with the site’s participation in the ResearchBlogging tracking system for blog posts about journal articles. For this edition of Hourglass, Reason has submitted two excellent analyses of recent papers, and a third piece of a more philosophical bent:

It is from the last piece that I’ve chosen an excerpt:

Wouldn’t it be nice to wake up and find that we were all immortal? That would save a whole lot of work, uncertainty, and existential angst – and we humans are nothing if not motivated to do less work. The best of us toil endlessly in search of saving a few minutes here and a few minutes there. So it happens that there exist a range of metaphysical lines of thought – outside the bounds of theology – that suggest we humans are immortal. We should cast a suspicious eye upon any line of philosophy that would be extraordinarily convenient if true, human nature being what it is.

Moving on from a philosophical post written by a scientifically minded life-extension advocate, our next posts are scientific posts written about life extension from a political philosopher. Colin Farrelly of In Search of Enlightenment has submitted two long, thoughtful articles, the first about the clinical and social importance of tackling aging, the second about the cognitive biases that affect the way we think about risk and the significance of aging as a cause of mortality:

The “availability heuristic” was a new one on me. Here’s an operational definition as it applies to our thinking about aging:

In a rational world, aging research would be at the forefront of a global collaborative initiative to improve the health and economic prospects of today’s aging populations (and all future generations).

But humans are not rational. We suffer many cognitive biases. One prominent bias is the availability heuristic. Risks that are easily brought to mind are given a higher probability; and conversely, the less vivid a risk, the more likely we are to underestimate the probability of their occurring.

The two tests above reveal how prominent this heuristic is in your own comprehension of the risks facing yourself, your loved ones and humanity. Because death by aging is not something that is vivid is most people’s minds (though it is in the minds of the scientists who study the biology of aging and thus know all too well how it affects a species functional capacities), odds are you probably underestimated it as a risk of mortality.

The benefits of lifespan extension, both with regard to human health and society as a whole is sometimes called the Longevity Dividend. Alvaro Fernandez from SharpBrains sent in a long piece about the Longevity Dividend (written by a contributor from the Kronos Longevity Research Institute ). Ever heard of the Longevity Dividend? Perhaps Gray is the New Gold:

The Longevity Dividend is a theory that says we hope to intervene scientifically to slow the aging process, which will also delay the onset of age-related diseases. Delaying aging just seven years would slash rates of conditions like cancer, diabetes, Alzheimer’s disease and heart disease in half. That’s the longevity part. … The dividend comes from the social, economic, and health bonuses that would then be available to spend on schools, energy, jobs, infrastructure—trillions of dollars that today we spend on healthcare services. In fact, at the rate we’re going, by the year 2020 one out of every $5 spent in this country will be spent on healthcare. Obviously, something has to change.

Alvaro, the editor of SharpBrains and founder of the parent website, has recently published a book, The SharpBrains Guide to Brain Fitness, which is the subject of this recent (and quite favoriable) review. If you’re interested in learning more, here’s list of cognitive fitness references, based on the authors’ research for the book.

That’s all for now. If you’d like to host a future installation of Hourglass, please email me.

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