Starvation and autophagy: Cellular cleaning will rejuvenate your body
October 3, the Nobel Assembly at the Karolinska Institute awarded the Nobel Prize in Physiology or Medicine, asinari Osumi for the discovery of mechanisms of autophagy.
What is autophagy? Autophagy (from al-Greek. auto – "self", pages "is" is) – the self-blame. In fact, this mechanism of getting rid of all that performed its role, old cell components (organelles, proteins and cell membrane) when the cell is not enough energy to support them. This adjustable structured process aimed at the decomposition and recycling of cellular components.
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There is similar to autophagy and better-studied process of apoptosis – process of programmed cell death. Cells are programmed to death after a certain number of cycles of division. Although it sounds bleak, but you must understand that this process is important for maintaining good health in General.
Suppose you own a car. You love your car. You have connected with it many memories. You like to drive it. But after a few years of use it already looks a little beat up. After a few years it is quite unimportant. Machine support costing you thousands of dollars a year. She breaks down all the time. Should I continue to keep this piece of junk? Of course not! You get rid of it and buy a brand new car.
The same thing happens in our body. Cells become old and useless. And they'd better be programmed to death, when their useful life has come to an end. It sounds very cruel, but that's life. The process of apoptosis in which cells are doomed to destruction after a specified time. It's like leasing a vehicle after a certain time you get rid of it, it works or is broken. Then you buy a new car and you don't need to worry that it will break in difficult times.
Autophagy – replacement of old cellular components The same process occurs at the subcellular level. You do not need to change the whole car. Sometimes you just have to replace the battery is to throw away the old and put new. The same is happening inside the cell. Instead of destroying entire cells (apoptosis), you just need to replace some cell components. This is the process of autophagy in which old sub-cellular organelles are destroyed and create new organelles to replace the old. Old cell membranes, organelles, and metabolic products are removed from the cells, once in the lysosome, which contains enzymes to break down proteins.
Autophagy was first described in 1962, when researchers first noted an increase in the number of lysosomes (organelles, subcellular components decomposing old) in the liver of rats after injection of glucagon – a hormone of the pancreas. Nobel prize winner Kristan de Dyuv coined the word "autophagy". The damaged subcellular components and proteins is unused token "to destroy", and they are sent to lysosomes, finishing their work.
One of the key regulators of autophagy is the protein kinase called the "mammalian target of rapamycin" (mTOR). When mTOR is activated, it suppresses autophagy and when mTOR is inhibited, it contributes to autophagy.
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What activates autophagy?Limiting nutrients is essential for triggering autophagy. The hormone glucagon is opposite to insulin. As in the children's game "opposite day". If the insulin level increases, the level of glucagon decreases. If insulin falls, glucagon increases. When we eat, insulin increases and glucagon falls. When we don't eat (starve), insulin falls and glucagon increases. This increased level of the glucagon stimulates the process of autophagy. Starvation, which increases the glucagon is, in fact, the best stimulator of autophagy.
It is, in fact, the type of stem cell harvest as a body identificeret old and non-standard cell components and mark them for future destruction. Accumulation in old cells of these cell components can be the cause of many effects of aging.
Fasting is useful not only from the point of view of stimulation of autophagy. Stimulating autophagy, we treated cells from old proteins and products of metabolism. On the other hand, starvation leads to the production of growth hormone, pointing to our body, that he began to produce new cellular components. Thus we have fully updated our body.
Before you put new things, you need to get rid of the old. Imagine a kitchen renovation: if you're from the 70's hanging shabby dirty-green cabinets, then they will have to throw out before you hang a new one. Thus, the process of destruction (removal) is just as important as the process of creation. It would be terrible to hang new shelves. Fasting can reverse the aging process by getting rid of old cellular components and replace them with new ones.
Height adjustable processAutophagy is height adjustable process. Out-of-control, autophagy may cause damage, so that should clearly be controlled. Full depletion of the free amino acid pool in mammalian cells is a powerful signal for autophagy, although the role of individual amino acids varies. Amino acid levels in plasma, however, is nearly constant. It is assumed that signals from amino acids and growth factors, and signals from the insulin signaling converge through mTOR, sometimes called the main regulator of signaling nutrients.
So, when autophagy old cellular components are broken down into amino acids (building blocks for proteins).What happens next with these amino acids? In the early stages of fasting amino acid levels begin to rise. It is believed that these amino acids are obtained when autophagy is sent to the liver for gluconeogenesis. These amino acids can be also broken down into glucose in the process of the tricarboxylic acid cycle. Finally, these amino acids can become part of new proteins.
The consequences of the accumulation of old "junk" proteins inside the cell can be traced to two main conditions – Alzheimer's and cancer. In Alzheimer's disease is the accumulation of the abnormal protein beta-amyloid or Tau proteins that destroy brain cells and lead to dementia. It is reasonable to assume that a process similar to autophagy, is able to clear cells from old proteins, can prevent the development of Alzheimer's disease.
What "disables" the process of autophagy? Food. Glucose, insulin (or low glucagon) and old proteins can collectively "turn off" this process of self-purification of cells. Many of them are not required for this. Even a small amount of amino acid (leucine) can stop autophagy. Thus, the process of autophagy is a unique property of fasting – it does not happen when a simple restriction of calories or nutrition in the diet.
Of course, there should be a balance. Both insufficient and excessive autophagy can hurt you. And this understanding returns us to the natural cycle of nutrition and fasting and not continuous adherence to the diet. This provides a cell growth during the phase of nutrition and cellular cleansing during fasting, there is a balance. Life is just a balance.published
Author: Dr. Jason Fung, a translation of Nikolai Kuzmin