While wandering through the open access papers of PubMed Central - which are starting to accumulate more rapidly now - I noticed a readable item on stem cells and aging. You should take a look:

If many adult tissues and organs are continuously replenished by cells derived from stem cells, then why do they show signs of aging? One possibility is that stem cells themselves age and senesce, resulting in a decreased ability to replace worn-out progeny and/or the fact that they pass on aged phenotypes to their progeny.

Missing in this discussion until now is the effect of the cellular and molecular environment on stem cell properties, although the molecular re-programming of epithelial cells into pluripotent stem cells demonstrates the importance of the intracellular environment. Indeed, ample evidence exists showing that intrinsic and extrinsic regulators are inextricably linked in determining stem cell functional properties. Of special current interest is the extracellular stem cell environment, commonly referred to as the stem cell ‘niche’, as originally coined for hematopoietic stem cells in the bone marrow.

The paper starts with a good review of present thinking on the role of stem cells and their niches in aging. It then moves into the interest of the authors in latexin and modulation of the size of stem cell populations:

The qualitative changes in stem cells and the composition of the stem cell population with respect to qualitatively distinct subclasses is an important factor in stem cell aging. We have shown that amongst mouse strains there is a strong correlation between the rate of early hematopoietic progenitor proliferation and mouse lifespan. Moreover, we and others have observed large strain-specific differences in the maintenance of the [hematopoietic stem cell (HSC)] population during aging, thus suggesting that genetic regulation plays an important role in the way aging affects HSCs.

Using forward genetics, we recently identified a protein, latexin, whose differential expression in stem cells accounts for at least part of these differences in young murine hematopoiesis. We have showed that latexin is a negative regulator of stem cell number and acts through at least two mechanisms to modulate stem cell pool size: a) it decreases HSC cell replication and b) it increases HSC apoptosis. Therefore, in the hematopoietic system, and perhaps other organs, latexin influences aging and perhaps lifespan through its action on stem cells.

You'll recall the ongoing debate on decline in stem cell function: is it fewer stem cells, or is it that the stem cells are less active? Evidence exists to support both sides, but with all the work on age-related changes in stem cell niches over the past couple of years, things seemed to be swinging towards less active stem cells as the dominant explanation. Biology is always more complex than we'd like it to be, however, and the debate continues.

In an effort to give a shout out to our own fragrance blog, The Scented Life, I was asked to list my top five fragrances. Here are my five favorites:

1. Kiehl’s Original Musk
2. LAVANILA Vanilla Coconut
3. Philosophy Amazing Grace
4. YSL Opium
5. Aquolina Pink Sugar

What is your favorite fragrance?

image (c) Kiehls.com and Sephora.com

Share This

Chris Patil at Ouroboros has dropped two sets of recent research into our laps for consideration, with a focus on continuing efforts to understand the intricacies of human biochemistry as it relates to longevity and aging.

• Keeping up with IGF-I and FOXO
• No end to telomeres

I find most of the work on insulin metabolism and insulin-like growth factor-1 (IGF-1) somewhat heavy going. It's very much down in the depths of metabolic mechanisms, for all that it's related to straightforward demonstrations of single gene longevity mutations in lower animals. It's somewhat analogous to work on calorie restriction mechanisms - in that it draws together energy from food and longevity to a mysterious biochemical middle - but perhaps more opaque because practical applications aren't as advanced at this stage.

Telomeres are more intuitive, however:

Telomeres - the structures at the end of chromosomes - have a long history in biogerontology. Telomeres shorten with every cell division, essentially providing a 'clock' that ticks down until reaching some critical length, at which point the cell will undergo the permanent growth arrest known as senescence. Even though this clock is an important tumor suppression checkpoint (because it prevents cells that have divided many times from continuing to proliferate), senescent cells themselves contribute both directly and indirectly to aging (by diminishing regenerative capacity and secreting deleterious signaling molecules, respectively). Telomere length is also a useful biomarker: it is positively correlated with life expectancy, and appears to respond to environmental influences including chronic infection and psychological stress.

One item of note in the list is that telomerase appears to have other roles beyond lengthening telomeres:

recent studies have led some investigators to suggest novel biochemical properties of telomerase in several essential cell signaling pathways without apparent involvement of its well established function in telomere maintenance. … This review will provide an update on the extracurricular activities of telomerase in apoptosis, DNA repair, stem cell function, and in the regulation of gene expression.

This is important for those groups working on telomerase-based therapies, and has implications for the viability of the proposed WILT strategy that would disable telomerase in order to eliminate cancer. As always, it's a challenge to interfere precisely in human biochemistry when every component has multiple important functions.

In case you haven’t read about my contest for a 6 month supply of Sensa, you can check out my post below. And in case you have not entered, be sure to do so and soon. The contest will end tomorrow night at 11:59 PM est, so enter now.

image credit: Sensa 

Share This

Who isn’t crunched for time? Crunched for money? In this day and age of there not being enough hours in the day or money to make ends meet, everyone is searching for easier solutions. Many of us are giving up our little luxuries, and pampering is certainly going to the wayside. I have found that by doing things at home not only saves me time and gas money, I am actually finding myself relaxing a bit doing my own facials and skin care treatments.

Doing this at home can be done using things that you have - no need to buy expensive kits or at-home facial products. Look through you beauty cabinet (or closet, as in my case) to find something that might work as a facial. I selected two products from Renee Rouleau to do my own little at-home facial.

I first used the Micro Crystal Cream ($37.50) to wash my face.

I warmed my face with a warm wash cloth and then applied a generous amount of the cream to my hands and slowly massaged my face. While I was doing this, I leaned over the sink with hot water running to help get some of the steam benefits. The cream says to massage for 60 seconds, but I took my time and did it for about three or four minutes. My skin immediately felt smooth as the Aluminum Oxide-micro fine crystals helped to smooth my skin. What I really liked about this was how my face felt after using it. I rinsed the cleanser off and then opened another almost hot washcloth and let it sit on my face until it felt cool.

Next, I opened a jar that contained the Vitamin C Mask ($36.50).

This is a clay based almost thick feeling cream that glides over skin. It smells nice and starts to tighten as it dries, which takes about a half an hour to be fully dried. I took yet another washcloth and ran it under hot water and placed it over my face to loosen the mask. As it started to cool, I massaged the mask off of my face and then rinsed until it was clear of the mask. My skin looked instantly brighter and whiter with it’s powerful yet stable form of Vitamin C and the melanin suppressing properties for lightening skin discolorations.

I am so impressed and will be making this mini-facial a once or twice a week habit. For a total of $74 and never leaving the house, I am sure to have a few months worth of mini-facials with using just these products alone.

To find out more about Renee Rouleau and her products, be sure to visit her online.

images credit: Renee Rouleau

Share This