Ageing and the cause of death. Monamine oxidase, a death system? Natural death, does it exist? Are death systems reasonable? We will discuss these and related questions in 2 articles, of which this is part 1.
I. Ageing and the Cause of Death
Ageing is a very inexact concept. When used in everyday speech, it is hardly ever a question of genuine ageing, but of disease or deteriorating health; often of self-afflicted damages, gradually accumulating through several decades and eventually reaching a critical point where noticeable symptoms occur. Few individuals, if any, are dying of old age; or are even starting "natural" ageing before they decline and die by slowly advancing degenerative disease. Those diseases are not necessarily age-related, but it takes so long for them to develop that they are commonly (and often incorrectly) defined as such.
There are several theories about genuine ageing, what it is, what causes it, etc. Most scientists believe that there is only one explanation and if it were just possible to find it, the mystery of ageing and death itself would finally be solved. Personally, I disagree. Ageing, the body's final breakdown and death - whether it is due to genuine ageing or to disease - is certainly a complex and complicated process, involving many factors.
One theory is the one about oxidation and free radicals. Many, many studies have shown that it is firmly anchored in reality, although it has proved to be more complicated than first believed to be. But it deals with the origin of disease and death by disease, not with genuine (natural) death.
A second theory claims that the cells are all the time amassing waste and that they cannot get rid of all of it. Gradually the amount will grow to a level where the cell can no longer function properly. It declines, gets dysfunctional and finally dies.
This procedure certainly takes place, waste amasses when the natural cleansing system is over-loaded or reduced in capacity. But this is not inevitable. There are methods to cleanse the cells. This is a theory of the origin of disease, but again, not one of the causes of natural death.
A third theory claims that the immune system is declining with increasing age, finally getting so weak that diseases claim and kill you. But is this a theory at all? It is an observation of two coinciding phenomena, high age and weak immune system, but why would there be a causal relation between them? Probably there is not. A declining immune system is, in my opinion, a symptom of disease, not of calendric age.
Theory number four assumes that the enzymes in the cells' interior are ageing, getting worn out after having functioned for a certain length of time. After that they gradually become less efficient and finally stop working entirely. Then the biochemical processes of the body stop and you die. Here, too, we might question the causal relation, but we can save ourselves that trouble. This theory has been disproved by several studies. They have shown that the enzyme activity and the protein synthesis as such stay at the same level irrespective of the individual's calendric age. A long time in a bad chemical environment can be bad for the enzymes and inactivate or kill them, but not age as such.
II. Monamine Oxidase, a Death System?
Do we have pre-programmed, built-in death systems which prevent us from living too long? That is the idea behind some theories (as theory three and four above). There is no proof of anything like that. On the other hand, there is no proof against it either. As soon as observations are indicating a death system, there is always the problem of causality and coincidence. Many processes which have first been considered a result of ageing have later been shown to be stoppable or even reversible.
One process I would like to mention is the seemingly age-related decline of dopamine.
Dopamine is a neurotransmitter, one of the many chemicals that carry signals between nervous cells. Without going into too much scientific detail here and now, suffice it to say that it is essential to vitality - that is to say such fundamental functions as fine motor control, immune function and sex-drive. Indeed it seems to be related to ageing itself.
The rate at which dopamine declines varies from individual to individual, but on an average the level is relatively constant up to 40-45 years of age, then it declines by about 13% per decade. When it reaches 30%, you get Parkinson's symptoms. When it reaches 10% you die.
MAO (Monamine oxidase) is an enzyme regulating the breakdown of neurotransmitters (mainly used ones). Levels of MAO increase with age and thus levels of neurotransmitters (like dopamine, serotonin and noradrenaline) decline with age. [In the United States "noradrenaline" is called "norepinephrine".]
Substances acting as MAO inhibitors can correct this and reduce the (age-related?) fall of neurotransmitters. Too much inhibition, however, can be dangerous, building up too high levels of neurotransmitters and causing hyper stimulation, a state that is related to the effect of amphetamine, including a serious and dangerous condition called the "cheese reaction".
The trick would be to use an inhibitor of only one form of MAO, called MAO-B. (The other form is called MAO-A.) Used in the correct dose it would achieve the desired effect without causing any of the undesirable side-effects. While usually MAO inhibitors are inhibiting both MAO-A and MAO-B, there is one known substance that is "selective", that is to say it inhibits only MAO-B. In medical literature it is usually referred to as "deprenyl" or "selegiline".
Deprenyl was long considered as very safe, one of the safest medical chemicals around. It had been used since the 1950s, so it was well tested. Its main use is against Parkinson's disease, but it is widely used for anti-ageing purposes as well. On laboratory rats it has been shown to extend the maximum lifespan by 40%! However, negative side-effects have been discovered and today its use has dropped. A new generation of MAO-B inhibitors, safer than Deprenyl, might be on is way, but nothing so far is suitable for self-medication.
It is not known why MAO increases with age. Is it a result of some sort of degenerative disease that can be stopped and even reversed? Or does it depend only on ageing itself? If age is indeed the only reason (which I doubt), we would have a genuine death system here whose purpose would be to limit the length of our lives.
III. Natural Death, Does It Exist?
By natural death I mean a death caused by age only, or by disease that is caused by age only - which neither optimal conditions nor extensive knowledge could have prevented. We will never reach such conditions and knowledge, so the question is purely theoretical. But does such a natural death exist? The most reasonable answer is that I don't know. We don't know. Science doesn't know. And we probably never will.
So, how long is it theoretically possible to live?
There is no proof of any specific limit and there is no proof that any specific limit exists, or would ever be possible to establish. The only thing one can say is that with the combination of old and new knowledge, it is possible to live a very long life, an active life in good health.
Some optimists believe that total immortality would be possible - never to die. In my opinion that is wishful thinking. Total immortality is impossible. Even if there would be no other objection (which is very unlikely), the matter of adaptation to changing outer conditions would sooner or later require more than an individual of any species would be able to handle.
Between generations there can be leaps of adaptation, due to mutation or due to natural selection slowly and gradually changing a species to make it better suited to manage in a new environment. But for a separate individual of any species, including humans, adaptability is limited. We can extend it by the use of tools, of technology, but somewhere there is a limit.
This is why species with a very rapid regeneration, like bacteria, or even mice, can so quickly adapt themselves to a very much and fast changing environment.
IV. Are Death Systems Reasonable?
Would there really be any evolutionary purpose in an inherent system that prevents us from living too long?
That would depend on what we think is the purpose of life. From a purely biological perspective, it would appear to be regeneration, to produce offspring and thus preserve the species. Then the survival of one individual beyond what is needed to produce (and, when applicable, raise) offspring, would be undue strain on the environment and on available resources. From that perspective, a system of automatic biological suicide could make sense.
But can a long individual life never be an evolutionary advantage? It has previously been mentioned that a species with a rapid regeneration is better at adapting to changes of the surrounding environment. So for biological adaptation, a rapid regeneration is an advantage.
Rapid regeneration combined with long individual life-spans would not be advantageous. It would quickly lead to overpopulation of that species. Required resources (like food) would get exhausted and the environment would be poisoned by trash. The species would not survive.
Consequently, successful species with rapid regeneration also have relatively short life-spans; while long-living individuals reproduce relatively slowly.
But if biological adaptation was the only precondition for success, then all species would evolve to faster and faster regeneration, and consequently shorter and shorter individual lives. This is not the case, so obviously there are other factors involved.
Such a factor is, I think, knowledge. Not inherited instincts, but achieved knowledge. Learned from experience or from other individuals. Such knowledge increases the ability to survive. This is intelligence, creativity and the ability to build a mental or intellectual culture (this should not be understood only in a limited human sense) - and to hand it over to the next generation. It requires time, individual life-time. Teaching and learning take time.
From this perspective, a long life is evolutionarily advantageous. With more time, you can gather more useful knowledge, and the transfer of knowledge gives a useful task for individuals beyond reproductional age.
Too long individual lives would still be disadvantageous, because they would require too slow reproduction to maintain the population balance. So the evolutionary optimum is probably somewhere in between. Medium life-spans, medium speed of reproduction.
(Read also part 2 of this discussion: Telomeres, Rate of Living, Hormesis & Ageing.)
(This article is based on material previously published in TMA & Meriondho Leo 2005-2016, and in my e-book “Paradigms of Health”, 2019.)
Copyright © 2005, 2016, 2019, 2021 Meleonymica/Mictorrani. All Rights Reserved.
(Lead image by Lothar Dieterich/Pixabay, CC0/Public Domain. The colours of the original have been digitally changed.)
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I don't know what you have concept about death 💀 but one thing I know everyone will die sooner or later and only Allah know how we die. May be that deaths will be natural or by accident