Ouroboros: Research in the biology of aging)
Cellular senescence is regarded as a tumor suppressor mechanism:
damaged cells permanently leave the cell cycle (preventing tumor
initiation), and also secrete factors that trigger both tissue
repair and inflammation in the vicinity. This is probably good at
first but bad later on: persistent senescent cells also secrete
growth factors and metalloproteases that degrade the tissue
microenvironment and encourage nearby preneoplastic cells to
progress into full-blown tumors. Thus, senescence has been
implicated in late-life cancer and age-related decline in tissue
The “damage” in question is usually genotoxic in nature:
telomere shortening, indicating that a cell has undergone many
rounds of potentially mutagenic cell division, or high levels of
DNA damage such as that resulting from
ionizing radiation or exposure to chemical clastogens. Oncogene
expression probably also induces senescence via DNA damage, by triggering over-firing of replication
origins and generating broken ends and weird chromatin structures
that are interpreted as damage.
Now it appears that falling cellular ATP levels may also result in cellular senescence.
Unterluggauer et al. report that inhibition of
glutaminolysis (preventing cells from generating ATP from glutamine, an unglamorous and occasionally
overlooked pathway that is nonetheless an important energy source
in many cellular lineages) results in increased senescence in human
vascular endothelial cells (HUVECs): (cont.)
Worried about how Fluffy will handle being in the cargo hold at 35,000 feet? For just $1,780 you can purchase a Cryo-Pet™ which uses the latest cryonic technology to put your pet into a gentle slumber.
Although the operation of such a device may seem rather daunting, Cryotranz™ hopes that by combining their newest cryo-breakthroughs with eye-appealing design that cryonics will move past the image the industry has of just freezing the heads of the rich and break into the mass consumer world.
How does it work?
On the side of Cryo-Pet™ you’ll find a “Pre-Cryo Preparation Kit” which contains all you need for putting your animal into a suspended state.
First, a breathing nozzle is used to deliver two different chemicals to your animal. One is a drug which will knock your pet out for easy handling, the second is a chemical which enters into the blood stream and begins slowing the metabolism of your animal. The effects only last for about thirty minutes in case you change your mind.
After your animal is asleep, place him or her into the chamber and close the door. A button will light when the door has been locked and his or her metabolism and breathing has stopped. Cryo-Pet™ is then ready to begin the freezing process.
What happens during the freezing process?
Much has been made of Caloric Restriction (CR) and how it is the one true life-extension strategy currently available. In countless articles and videos it has been given much attention and there are a bunch of folks whose stomachs are growling as we speak that will be disappointed to learn that this strategy may be flawed.
A new study by Raj Sohal and Michael Forster recapped on EurekAlert! shows that CR is essentially only effective when "an animal eats more than it can burn off." The problem it seems is that it really only works for obese mice and has little or no benefit for those who aren't.
The study looked at two different genetically altered strains of mice - basically a fat mouse and a skinny mouse (I think this may have sitcom potential). The takeaway was that calorie restriction helped the mouse that had been programmed to double its weight over its lifespan while it did not extend the life of the skinny mouse. In fact, when CR is started later in life they found that it actually shortened the lifespans of leaner test subjects. The authors noted that previous studies have also demonstrated that wild mice experience minimal life-extension benefits from CR.