Imagine you have a clock that allows you to measure the age of almost every cell in your body with astonishing accuracy. What sounds like an invention from the future is already possible today. We owe this to a mathematician, the German-American researcher Steve Horvath. With the clock named after him (English: Horvath clock), we can determine the biological age of cells with month precision.
In this article, we dive deep into the world of the Horvath Clock and explain what makes this epigenetic clock so unique, how it works, and what implications it has for aging research. You will also learn more about its discoverer, Steve Horvath.
Who is Steve Horvath?
Steve Horvath is a German-American biostatistician, geneticist, and leading researcher in the field of aging research.Born in Germany and later immigrating to the United States, Horvath currently teaches as a professor of human genetics and biostatistics at the University of California, Los Angeles (UCLA).
From an early age, Steve Horvath was fascinated by the concept of aging. In particular, the question of how to live longer in good health occupied young Steve Horvath greatly. Together with his twin brother and a mutual friend, the three vowed to strive in their professional lives to answer the question of healthy aging. Their role model was the ancient Babylonian epic of Gilgamesh, who dives into the depths of the ocean in search of eternal youth to find the herb of immortality there.
Although Steve Horvath did not discover "the herb of immortality," he developed a mathematical model that allowed him to depict aging itself.And with that, so his hope, the foundation has been created to also reverse aging.
What is the Horvath Clock (epigenetic clock)?
The Horvath Clock is an epigenetic test that measures the biological age of an individual. The basis of this method is the analysis of DNA methylation patterns, which systematically change over time. DNA methylation is an epigenetic mechanism by which methyl groups are added to DNA molecules, thereby influencing gene expression without altering the DNA sequence.
Steve Horvath discovered that certain regions of DNA - known as CpG sites - exhibit systematic changes in their methylation patterns over the course of life.By investigating and mapping these specific changes, Horvath was able to create an "epigenetic clock" that predicts the biological age of an organism very accurately based on the methylation at 353 specific CpG sites.
Did you know?
Steve Horvath's scientific work was initially rejected by many editors. The results and accuracy of the Horvath clock were said to be “too good to be true.” After several rejections, Steve Horvath first treated himself to three bottles of beer and then wrote an angry letter to the editor. Successfully, his article was subsequently published in the renowned “Genome Biology.”
Measuring biological age with the Horvath clock
Traditionally, a person's age is defined by chronological age, that is, the number of years since birth.The biological age, on the other hand, refers to the physiological state of the body and can differ significantly from chronological age. A younger biological age may indicate better health and a longer life, while an older biological age can indicate an increased risk of age-related diseases and premature mortality.
The Horvath Clock provides a method for assessing this biological age by analyzing the pattern of DNA methylation in blood samples, saliva, or other cell types. This methodology has proven to be extremely accurate and offers valuable insights into the aging process at the cellular level.
Did you know?
The biological age is incredibly accurate even by scientific standards. Biomarkers have a correlation of about 0.6 to 0.7.For comparison, the length of telomeres, for which Elisabeth Blackburn received the Nobel Prize, has a correlation with age of 0.5. The Horvath Clock showed an impressive correlation of 0.96!
In other words, the Horvath Clock is a very accurate measuring instrument.
The basis of the Horvath Clock: Epigenetics and DNA Methylation
Epigenetics is a field of research that deals with changes in gene expression that occur independently of changes in the DNA sequence. Epigenetic mechanisms, such as DNA methylation, play a key role in the regulation of many biological processes and are crucial for an organism's adaptability to environmental factors.
The Horvath Clock uses these epigenetic principles to estimate biological age.By systematically capturing the methylation states of 353 specific CpG sites, the clock can make precise predictions about the biological age of the tested tissue. These CpG sites were identified based on their strong correlation with chronological age in various tissue types, making the Horvath Clock a universal tool for different biological samples.
Methylations, Epigenetics – is there an easier way?
Admittedly, many of the mentioned concepts are highly scientific. To help you gain a better understanding without having to read dozens of studies, we will try to explain the connections here using an example.
Imagine your DNA as an oversized orchestra. Around each instrument are volume controls that can be turned up or down.These volume controls symbolize epigenetics. Through various biochemical processes (such as the aforementioned methylation), our body can adjust certain areas of DNA to be louder or quieter. Translated, this means that epigenetics determines which parts of the DNA are read and which are not.
Steve Horvath has now discovered that there are very specific patterns in the setting of these volume controls for aging. And that is exactly what the Horvath clock measures. Thus, Horvath can quite accurately say how "old" a cell is on a biochemical level.
Applications of the Horvath Clock in Research &and Medicine
The Horvath Clock has far-reaching applications, both in basic research and in clinical and medical contexts:
- Research on Aging and Longevity: The Horvath Clock allows scientists to investigate the influence of various factors on the aging process. These include environmental factors, genetic predispositions, and lifestyle changes. Research findings can be used to develop strategies for health promotion and life extension.
- Early Detection of Diseases: The biological age, measured with the Horvath Clock, can provide early indicators for age-related diseases such as cardiovascular diseases, cancer, or neurodegenerative diseases. This enables early interventions and targeted preventive measures.
- Monitoring of Therapies: The Horvath Clock can be used to assess the success of anti-aging therapies or other medical interventions. Changes in biological age could indicate how effective a particular treatment is.
- Clinical Studies: In clinical studies, the Horvath Clock can be used to evaluate the effects of new drugs or interventions on the aging process, thereby determining their potential benefits or risks before market introduction.
Horvath Clock, Molecular Profile, DunedinPACE or TruAge – what is behind the new generations?
In addition to the Horvath Clock, there is now a whole range of epigenetic tests that can measure biological age.The concept is still largely the same, meaning that the newer tests also measure methylation sites on the DNA. Tests like the DunedinPACE test indicate how quickly one ages. If you're wondering where the name comes from, Dunedin is a city in New Zealand where the data for the test was collected. The DunedinPace and the TruAge test are also the basis for the Rejuvenation Olympics.A competition initiated by American Bryan Johnson to determine who ages the slowest. This has attracted other biohackers besides Bryan Johnson, including the 61-year-old z.BDave Pascoe, who has a biological age of just 38 years. Quite impressive.
What influences the Horvath Clock?
For more than 10 years, the Horvath Clock and its successors have been tested.Some interesting facts emerged. The most astonishing is that biological age is modifiable. In particular, the biohacker scene has impressively demonstrated that one can turn back their biological age.
But what about the other direction, and are there also cases where biological age changes only for a short time?
Older biological age – a risk marker?
In the scientific community, there is still no consensus on how to interpret the results of the Horvath clock. Are they "just" a mathematical model, or do they really reflect aging processes in our body? To clarify this question a bit better, researchers have analyzed huge amounts of data. A connection became quite clear.People with a high discrepancy between chronological age and biological age have an increased risk of developing certain diseases, z.B. of the cardiovascular system.
OP, stress, and infections as short-term influencing factors
Imagine you took a test to determine your biological age and you are older than expected. For many, this is certainly a shock, and it raises the question of whether one now has an increased risk for certain diseases. This example clearly shows that measuring biological age does not always provide the complete picture. Because it is also influenced by short-term events.
To demonstrate this effect, researchers examined various scenarios in a study:
Surgeries make us older - at least in the short term
Surgeries mean a lot of stress for our body. It was therefore reasonable to assume that this affects our biological age. And indeed. Shortly after a surgery, biological age shot up. This is likely a sign from our body that it is using many resources for repair. The good news is that just a few days after a procedure, biological age normalized.
Infections influence the Horvath clock
Infections, such as COVID-19, also have a measurable effect on our biological age. They make us appear older for a short time than we actually are.For this reason, it is advisable not to take an epigenetic age test when feeling unwell or just recovering from an infection. The results may be distorted.
And one last exciting point that the researchers found in their work.Stress seems to not only make us appear older externally, but it also affects our biological age internally.
Case Studies: Practical Applications of the Horvath Clock
In recent years, the Horvath Clock has established itself as a solid tool in science. We now know that biological age can provide us with very reliable information about our health. The right nutrition, exercise, and stress reduction can lower biological age.
Similarly, the Horvath clock and its successors can be used to test potential molecules in longevity research. For example, in one study, the molecule alpha-ketoglutarate was tested for 7 months. The participants took a mix of alpha-ketoglutarate and vitamins daily during this period. The impressive final result: Participants were able to reduce their biological age by an average of 8 years!
Challenges and Future Research
Despite the impressive successes of the Horvath Clock, there are still challenges and open questions. One of the biggest challenges is to better understand the mechanisms underlying the epigenetic changes measured by the Horvath Clock.A deeper understanding could help develop targeted interventions that could slow down or reverse the aging process.
Moreover, it is important to conduct further validation studies to verify the accuracy of the Horvath Clock in different populations and under varying environmental conditions. Such studies could help confirm the general applicability of the clock and identify potential limitations.
Conclusion: The Revolution of Aging Research
The Horvath Clock and the research of Steve Horvath have revolutionized our understanding of aging. By precisely measuring biological age based on DNA methylation markers, the Horvath Clock provides valuable insights that go far beyond what is possible through conventional measures of chronological age.These findings have the potential to improve the prevention and treatment of age-related diseases and to develop strategies for promoting healthy aging and extending lifespan.
Steve Horvath's work impressively demonstrates how interdisciplinary research and innovative thinking can lead to groundbreaking discoveries. The Horvath Clock is a prime example of how epigenetic research can find practical applications in everyday life and offers all people a better quality of life.
This article was created by the MOLEQLAR editorial team and follows our editorial guidelines.
