Klotho Protein and The Fight Against Ageing

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Klotho is a protein which has become much lauded for its anti-ageing properties. Deficiency has been linked to degenerative changes in tissues and systems throughout the body. It’s an exciting and relatively recent area of research, with emerging evidence getting us closer to understanding its precise role, the value of interventions to increase levels… and determining what may be the best- i.e. safest and most effective- way to do so. 

Key Points:

1) Klotho is a protein which tends to become less abundant within the body with age, and which appears to have anti-ageing properties. The abundance/lack of klotho in the body is linked to the health of the cardiovascular system, kidneys, stem cells, cartilage, the brain, perhaps the body more generally- and cancer status.

2) However, there are a number of weaknesses in the research (including common ones such a reliance on animal, tissue culture and correlative studies, and more specific weaknesses in the research methodologies used). We can only definitively say that klotho is linked to age related deterioration, and not a cause of it.

3) It is possible too much klotho would have detrimental effects.

4) The research suggests the most reliable way to increase klotho levels to date is through aerobic exercise. Supplements or other medical interventions are not within reach as yet, as a number of issues have to be overcome to ensure they are safe and effective. 

5) If all goes well with research, in the future we may gain a fuller understanding of the role of klotho in the human body, and medical professionals may be able to deliver highly individualised interventions according to people’s specific needs.

Discovery of klotho protien

Like the slinky, velcro and many other great things, klotho was discovered by accident. Since that fortunate ‘oopsie’ in 1997, epidemiological, clinical and lab research has shown how important a humble protein may be. Early findings were that mice deficient in klotho prematurely aged and had shorter lifespans; whereas correcting deficiency gave them a 30% longer lifespan than wild mice. 

Many of the less-desirable changes associated with aging were also found in klotho deficient mice… including shrinkage of multiple organs and muscle, changes to the cardiovascular system, weakening bones, impaired cognition and hearing, and increased frailty. Increased levels may be protective in these matters, but exactly how it works is incompletely understood. 

What role does it have in the body?

A high proportion of klotho genes are found in the kidneys, meaning they’re the significant producer of protective klotho proteins. It is thought that the kidneys release klotho into the blood to circulate and regulate the health of the whole body. 

Klotho genes also have a decent distribution in the parathyroid gland and placenta; to a lesser extent, in the lung, fat and parts of the brain; and in still lesser amounts elsewhere in the body. In contrast to the kidneys, It is thought that these tissues produce the protein to regulate their own local health.

Klotho protein comes in three forms: a transmembrane form which spans the surface of cells, with ends poking out either side. It is found in a few tissues- primarily in the kidneys. There is also the soluble form, found inside cells,  and the shed form which circulates through the blood and the fluid surrounding the brain and spinal cord. 

Generally, klotho levels naturally decline as time goes on, which in turn contributes to aging processes. It makes sense that reversing this natural decline could be anti-ageing.

Of course, aging has diverse effects on physiological systems, so let’s look a little deeper at the role of klotho throughout the body…

Klotho and the kidneys

As the primary producer of klotho, kidneys have a large responsibility, but are also particularly susceptible to ageing.

As you may have gathered, maintaining phosphate balance may be one of klotho’s primary protective actions. As phosphate levels increase in the blood, more of the protein Fibroblast Growth Factor-23 (FGF23 for short) is produced to help the kidneys excrete it. However, FGF23 requires the help of transmembrane klotho… recent studies have shown that the FGF23 receptor has to first bind to part of klotho, and the new structure that is formed provides a neat groove for FGF23 to fit into. Only then FGF23 can work its magic. Another study suggests that klotho may help excrete phosphate independently of FGF23. Either way, it is essential to the function of kidneys, and the protection of the body.

Image credit: Medical vector created by brgfx – www.freepik.com

While increased phosphate excretion may be protective for blood vessels and other tissues, it can lead to kidney damage. Particularly in the case of kidney disease, an increase in FGF23 indicates that phosphate levels are excessive for the working functional units of the kidneys. A review study from 2018 study suggests phosphate restriction, or possibly targeting tissue-damaging Calciprotein Particles (composed of calcium, phosphate and protein) as appropriate measures to maintain phosphate balance  in the case of kidney disease. This may be a better bet than increasing klotho to enhance FGF23 activity, thus adding to the work of the kidneys.

Klotho and the cardiovascular system

The deterioration of our cardiovascular system has been linked to reduced klotho levels – whether obvious heart diseases are present or there’s more insidious changes. The host of changes may include inflammation and oxidative stress, atherosclerosis and arteriosclerosis (artery stiffening). Arteriosclerosis in turn can result in increased blood pressure and possibly complications such as damage to the small vessels in key organs like the heart, brain and kidneys, and scar tissue formation on the heart.

As you may know, aging is often linked to DNA damage. However, mice models have identified phosphate to also be a pro-aging factor in mammals. High phosphate levels are toxic to cells and have been implicated in calcification of blood vessels and arteriosclerosis, and reduced lifespan, in mice and zebrafish. Likewise, excess phosphate in tissue culture studies caused damage, calcification and death among cells that provide lining and the muscular wall of blood vessels. Klotho helped to lower these phosphate levels into a safer range. 

While most of the studies are animal and lab based, a number of observational studies provide general evidence that circulating levels of klotho are inversely related to levels of cardiovascular disease and mortality.

Klotho and cancer 

The klotho levels in several types of tumours is lower than in normal tissues. It is hypothesised that some cancers can modify the relevant genes, thus silencing klotho protein activity. 

Increasing levels has been shown to suppress tumours, inhibit a pathway crucial to cancer invasiveness and spread, and facilitate death of cancer cells. 

Klotho and stem cells

While stem cells have therapeutic potential for multiple health conditions, their function declines with age. Klotho can enhance stem cell function, including proliferation, ability to develop into different cell types, plus reduced oxidative damage and protection of chromosomes from unwanted changes. It can’t do this alone, but requires the help of a compound known as telomerase, which is involved in DNA protection.

Klotho and cartilage

Osteoarthritis is known to progress with age. In mice, this has been linked to klotho depletions. In addition, raising levels has been seen to reduce the death of cartilage cells, offering more cushioning and support to joints. 

Klotho and the brain

Brain, canva.com

The effects of klotho on different areas of the brain definitely need to be elucidated, as do the modes of action. However, animal and tissue studies suggest some exciting possibilities: 

  • It may be protect against conditions such as Multiple Sclerosis and Parkinson’s Disease
  • Protection from oxidative damage 
  • Promotion of neuron regeneration and maturation
  • It seems to enhance memory and learning. The mouse hippocampus, essential to learning and memory, may be damaged with klotho deficiency
  • An injection with klotho has improved cognition in mice with symptoms of neural degeneration. Klotho is unable to cross the barrier between the central nervous system and the body’s blood supply, so it is unclear how this effect came about.
  • It may increase plasticity (the ability to form new neural pathways). A few areas of the brain are able to create new neurons throughout adult life. The ‘hippocampal dentate gyrus’ is one of these. However, its ability to generate new neurons does decrease with age. A small number of studies in mice and cell cultures suggests that klotho may have a role here, however, the mechanism by which it affects neuronal growth and maturity is unknown.
  • The choroid plexus (a cluster of cells) and cerebellum may themselves produce klotho.
  • In addition, it may help the choroid plexus keep the level of calcium within the fluid surrounding the spinal chord and brain within the correct range

Further studies- including human studies, of course- are needed to give meat to these ideas, and to determine if the effects are mediated by phosphate levels or whether klotho has more direct action/s on the brain.  

General effects

Binding of transmembrane klotho with the FGF23 receptor may also affect different genes and pathways involved in metabolic regulation.

The secreted form acts as a hormone and exerts actions on different pathways, leading to anti-oxidant production and reduced oxidative stress on various tissues including the liver, heart and brain. 

The soluble form could block the inflammatory products of immune cells, thus functioning as an anti-inflammatory and anti-aging factor within widespread cells. 

How do you increase your levels?

Aerobic exercise is one simple method to increase klotho levels, according to small numbers of human and animals studies. The effect appears stronger among younger people, and is greater among those who are aerobically fitter: distance runners have been found to have higher klotho levels than sprinters (who rely on anaerobic metabolism). The effect of other forms of fitness/training have not been thoroughly studied. Whether increases are maintained over a long period of time is also unknown.

Probiotics containing Lactobacillus acidophilus and Bifidobacterium bifidum may reverse age-related decline in klotho levels- at least it was shown to in a small study on mice.

Another option may be klotho supplementation. However, we are a long way from being able to formulate effective supplements to tackle aging. Synthesised klotho seems quite unstable and it’s activity can be greatly affected by handling. In addition, the quality of synthesised klotho protein varies unpredictably, which means its benefits (or potential risk) cannot be counted upon. 

Furthermore, a supplement or other medicinal intervention that can tackle the broad-range of aging changes is difficult to attain. Companies are currently exploring means of targeting more specific effects of klotho deficiency. For example, klotho synthesised in the lab may be used to treat kidney or other disease; alternatively, small molecules may be used to manipulate klotho production/action, or adeno-associated viral delivery may enhance klotho expression by the body. Further investigation is required to see if they can actually be used in clinical settings, however. For these good reasons, supplements or treatments are not currently commercially available. 

What is the hold up?

There are a number of technical problems in the research  that must be resolved before we can seriously consider Klotho therapies.For one, as mentioned above, klotho comes in three forms, each with different functions. Furthermore, analysis has found between 1,287 and 1,508 small variants in the protein’s structure, and these variants have been associated with a range of impacts including on bone density, blood pressure and blood glucose. We do not yet know enough about these variants, their role or mechanisms of action. If a variation is not just correlated with these physiological changes, but a causation, we need to elucidate which variants are most beneficial. 

A critical issue was highlighted in a 2019 review article: the results of many key papers failed to be reproduced by independent labs. This should cast a healthy dose of scepticism over the exciting findings that have been pedalled.

In addition, there is some question over the accuracy of the methods used to measure klotho levels. 

Many of the discoveries discussed are from animal or lab-based cell studies. As of September 19, 2019 no clinical studies have explored klotho’s effectiveness for us humans. Furthermore, most animal studies used mice in the first half of lifespan- and it is known that the older brain differs greatly to the young brain. Research needs to show what the effect of klotho is in older mouse brains, when therapy may be most required. Then, we can look for more clinical evidence relating directly to humans. 

If you need another reason to hold your horses- we do not have enough information on suitable doses and timings of supplementation, as most studies only examine the effect of klotho at single time points and/or with single doses.

Is there such a thing as too much?

There may very well be. For example:

  • In a lab model, high levels of klotho were found in cells subject to retinal degeneration
  • Mice with high levels have been seen to have high levels of blood FGF23 and vitamin D, which resulted in phosphatemia, increased calcification in the kidney and premature aging… similarly to that produced by klotho deficiency
  • Excess may result in rickets and hyperparathyroidism

Further research will help answer how much is too much. 

It is also possible that klotho may have a narrow window of efficacy, not only in dosage but in timing- outside of which it may itself cause harm. Mice given klotho 1-6 days after injury had their recovery impaired, whereas those given klotho 3-6 days after injury showed benefits. The latter timing schedule more closely mimicked natural responses of klotho to injury, in healthy young mice. 

In addition, the effect of klotho can be altered by age, comorbidities and other health considerations. 

Further studies are necessary if we are to understand what populations would be suited for klotho therapies. Even then, any method of increasing klotho levels needs to be highly tailored to the individual, under medical direction.

The Verdict

Animal and cell-culture studies provide strong evidence for klotho’s anti-ageing effects. We are awaiting sufficient human trials to definitively prove these, and to ascertain whether supplements are both appropriate and reliable.

In he meantime, engage in regular aerobic exercise and consider taking probiotics containing Lactobacillus acidophilus and Bifidobacterium. They may help increase/maintain your levels- and if not, they come with a bunch of other benefits anyway.

Image credit: Woman photo created by Racool_studio – www.freepik.com

Do you use or have you heard of any unusual anti-aging tricks? Let us know below!

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Lim, K., Halim, A., Lu, T., Ashworth, A., & Chong, I. (2019). Klotho: A Major Shareholder in Vascular Aging Enterprises. International Journal of Molecular Sciences, 20(18), 4637. doi:10.3390/ijms20184637

Makoto Kuro-o. (2018). Molecular Mechanisms Underlying Accelerated Aging by Defects in the FGF23-Klotho System. International Journal of Nephrology, Article ID 9679841. https://doi.org/10.1155/2018/9679841/

Mujib Ullah, Zhongjie Sun, Klotho Deficiency Accelerates Stem Cells Aging by Impairing Telomerase Activity, The Journals of Gerontology: Series A, Volume 74, Issue 9, September 2019, Pages 1396–1407, https://doi.org/10.1093/gerona/gly261

Singh, A.J., Sosa, M.X., Fang, J. et al. (2019). αKlotho Regulates Age-Associated Vascular Calcification and Lifespan in Zebrafish. Cell Reports, 28, 2767–2776. https://doi.org/10.1016/j.celrep.2019.08.013

Ullah, M., and Sun, Z. (2019) Klotho Deficiency Accelerates Stem Cells Aging by Impairing Telomerase Activity, The Journals of Gerontology: Series A, 4 (9) 396–1407, https://doi.org/10.1093/gerona/gly261

Vo, H.T., Laszczyk, A.M., and King, G. (2018). Klotho, the Key to Healthy Brain Aging? Brain Plasticity, 3 (2), 183-194. DOI:10.3233/BPL-170057

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