Measurement using epigenetic clocks
Have you ever felt younger than you are? Or vice versa – sometimes feeling older than you are? Now it is possible to find out if that feeling is actually true.
Difference between Chronological and Biological age
Aging can be measured in chronological age or biological age. Chronological age is counted from the time that has passed since birth and is strongly correlated with chronic diseases and age-related conditions. Scientific data have demonstrated that people born on the same day, although they share the same chronological age, may have different biological ages. Biological age thus provides information about general health as well as indicates how quickly or slowly a person ages cellularly and can be a key role in how we treat diseases and how early we can detect them.
Become biologically younger with the help of the right interventions
Studies have also shown that multiple age-related conditions, chronic diseases, social variables, and mental health are associated with an increased biological age relative to chronological age. Recent studies have demonstrated that estimated biological age is also sensitive to interventions. Some drugs, supplements, low-calorie diets, lifestyle changes, exercise, and quality sleep are capable of slowing or even reversing aging, which can be measured and trend-monitored with biomarkers from blood samples and saliva. This means that with the right medical knowledge and understanding of the age process, we can work proactively and preventively with health. It also means that you do not have to wait until you get sick to prevent, for example, chronic diseases.
The study is important for disease prevention
The development of tools for diagnosing and assessing age-related risks and health status is of great importance for the prevention of age-related diseases. It has been demonstrated that the age process can result in several changes, for example:
- At the molecular/cellular level
- Cell death,
- Impact on telomere length (read more about it in this article)
- Epigenetic changes
New model for evaluating biological age
In a recently published study, researchers have developed a new and more accurate model that can predict actual age based on our so-called epigenetic clocks (1).
Epigenetic clock
Then What is an epigenetic clock? It is a way to estimate biological age and predict longevity based on algorithms and machine learning. These ticking clocks are created with calculations of DNA methylation on specific CpG areas of our genome, which can provide an age estimate (read more about CpG areas and methylation at the end of this article). Thus, with the right clinical preconditions, these epigenetic clocks can be biomarkers to indicate outcomes and how well an individually adjusted intervention works.
Epigenetics acts as a link between inheritance and environment
Epigenetics are changes in gene activity without changes in gene sequence. In simple terms, it is external changes that control how your genes express themselves. Epigenetic changes therefore affect how your DNA is read and when and how it is expressed. An example of an epigenetic modification is DNA methylation which is strongly associated with biological aging.
Promising method for predicting disease risks
The development of age models based on the correlation between DNA methylation patterns (biological age) and chronological age is estimated to grow more and is a promising method for predicting disease risks. Thus, biological age can explain the variation in health status of individuals with the same chronological age. It has been proven that higher acceleration of DNA methylation is correlated with lower cognitive ability, muscle strength and lung capacity. An important risk factor for the acceleration of epigenetic age is cumulative and lifelong stress that can be mapped, diagnosed, and treated much earlier.
What are CpG islands?
CpG islands is a genetic term for areas on DNA strands containing a high value of cytosine followed by guanine. Study data have shown that methylation data measured from these specific CpG islands are highly correlated with age determination and prediction of longevity.
DNA Methylation and Epigenetic Clocks
DNA methylation is a biological process by which methyl groups are added to the DNA molecule. These methylations occur on CpG islands that are sensitive to methylation changes and affect gene expression. Thanks to this, it has been possible to identify these epigenetic clocks that are used as models to estimate age, health status and mortality risk.
Summary
The difference between chronological age and biological age can be measured using epigenetic clocks that examine DNA methylation in specific CpG areas. This is a promising method for examining an individual’s disease risks and longevity potential at an early age. Therefore, examining biological age can help doctors to earlier prescribe correct interventions that can reduce the risk of developing age-related diseases. Thus, there is a great need to develop and improve biological clock models. Partly from a commercial perspective, because it should be a simple sampling, partly from a cost perspective, because it should be cheap for the customer.
In order to make the analysis as cost-effective as possible, the clock model needs to be constructed on as few CpG data as possible but with maintained high accuracy and quality. There is also a societal aspect to this. Prejudice and discrimination that deals with subtle ageism in healthcare means that treatment is discontinued, and care deteriorates for individuals over a certain age range. If instead one could look past these numbers and see the human instead, we can also save those who could have been saved, not only based on chronological age but according to actual care needs!
References:
1. Li A, Mueller A, English B, Arena A, Vera D, Kane AE, Sinclair DA. Novel feature selection methods for construction of accurate epigenetic clocks. PLoS Comput Biol. 2022 Aug 19;18(8):e1009938. doi: 10.1371/journal.pcbi.1009938. PMID: 35984867; PMCID: PMC9432708.
Johnson AA, English BW, Shokhirev MN, Sinclair DA, Cuellar TL. Human age reversal: Fact or fiction? Aging Cell. 2022 Aug;21(8):e13664. doi: 10.1111/acel.13664. Epub 2022 Jul 2. PMID: 35778957; PMCID: PMC9381899.
Galkin F, Mamoshina P, Aliper A, de Magalhães JP, Gladyshev VN, Zhavoronkov A. Biohorology and biomarkers of aging: Current state-of-the-art, challenges and opportunities. Ageing Res Rev. 2020 Jul;60:101050. doi: 10.1016/j.arr.2020.101050. Epub 2020 Apr 6. PMID: 32272169.
Xiao FH, Wang HT, Kong QP. Dynamic DNA Methylation During Aging: A “Prophet” of Age-Related Outcomes. Front Genet. 2019 Feb 18;10:107. doi: 10.3389/fgene.2019.00107. PMID: 30833961; PMCID: PMC6387955.
Field AE, Robertson NA, Wang T, Havas A, Ideker T, Adams PD. DNA Methylation Clocks in Aging: Categories, Causes, and Consequences. Mol Cell. 2018 Sep 20;71(6):882-895. doi: 10.1016/j.molcel.2018.08.008. PMID: 30241605; PMCID: PMC6520108.