While aging is commonly considered a whole-person phenomenon, a growing body of research reveals that different biological systems and human organs age at varying rates. Emerging evidence highlights the natural aging process – and the variation in its rates – as reflective of a complex interplay of age, chronic disease, lifestyle factors, and genetic risks, all specific to the individual.

Understanding the rate of aging in different organs and biological systems is crucial for developing effective anti-aging therapies and targeted interventions. By identifying the factors contributing to the aging process, we can slow down or even reverse the aging process in different organs, potentially elongating our population’s health- and lifespans one organ at a time.

Varying Rates of Organ Aging

Despite efforts to quantify various age-related declines in functioning, age isn’t homogenous, even within a single human body. As emerging research elucidates, the biological aging process of human organs varies widely across the body.

A recent study published in Nature examined the aging process of seven body systems – cardiovascular, pulmonary, musculoskeletal, immune, renal, hepatic, and metabolic – and three brain systems – gray matter, white matter, and brain connectivity. The researchers identified organ age profiles for 16 common chronic diseases in which advanced biological aging extends from the organ of primary disease to multiple systems. Further, their results revealed that an organ’s biological age selectively influences the aging of other organ systems, suggesting the existence of a multi-organ aging network.

Although the organs that manifest primary disease processes are the oldest in patients with the disease, the research team found that in these conditions, advanced organ age is widespread and involves multiple systems.

Lead author Ye Ella Tian and her colleagues explain this further: “Brain systems of individuals with non-brain disorders, including diabetes, chronic kidney, pulmonary and cardiovascular diseases seem significantly older than same-aged healthy peers, whereas body systems, particularly pulmonary and renal systems, show signs of advanced aging in individuals primarily diagnosed with major brain disorders, including schizophrenia, dementia, bipolar disorder, depression, multiple sclerosis, and Parkinsonism.”

The study also found links between organ-specific aging rates and lifestyle and environmental factors. For example, proximity to green space was correlated with “younger” sets of lungs. Causal relationships were also reported, with lung aging resulting in increased heart aging and influencing the rest of the system’s decline.

By mapping the selective impacts of organs aging at variable rates, the study’s authors created a new way of quantifying and addressing age-related disease risk: the organ-specific biological clock.

Organ-Specific Biological Clocks 

For decades, the scientific community has investigated the human aging process in search of ways to delay, prevent, or eradicate it entirely. However, accomplishing this requires an effective form of measuring age and cellular aging. In 2013, Dr. Steve Horvath unveiled the pioneering epigenetic aging clock and inadvertently started the race toward identifying the most optimal method for measuring the rate and impact of aging on humans. To date, scientists cannot agree on the best method of measuring biological organ aging.

The latest scientific evidence puts into question our long-standing understanding of biological age and renders the concept of chronological age as a marker of aging increasingly simplistic. By establishing specific organ age clocks for the brain and body systems studied, the researchers could quantify not only the aging rate of organs but also determine the individual’s risk for chronic disease and premature mortality. The deviation between chronological and biological age can be detected in specific organs years before disease diagnosis, and these differences can successfully predict mortality risk.

As a systems-focused measurement of biological age that provides a comprehensive picture of patient health and aging rate, organ-specific biological clocks are quickly becoming the latest tool for predicting and treating both chronic disease and overall aging.

The Implications for Anti-Aging and Longevity Science

Deepening our understanding of the intricate aging process and the multi-organ network, the invaluable discovery of organ-specific biological clocks will have far-reaching implications for longevity science and our ability to extend the human health- and lifespan.

Early Detection and Treatment

The latest findings established organ age profiles for 16 chronic diseases and unveiled numerous modifiable factors – both discoveries could inform more effective disease-specific longevity interventions. This knowledge will likely serve as a foundation for developing innovative anti-aging strategies with more precise therapeutic targets.

Importantly, this knowledge has the potential to boost early detection and treatment rates for patients at an increased risk of aging-related morbidity and inform new strategies to limit organ-specific aging in such individuals. Organ-specific clocks can help identify at-risk patients before disease onset, promoting early treatment interventions and thereby optimizing health outcomes.

Furthermore, the evidenced variations in organ aging rates highlight the importance of targeted organ-specific screenings and the need for a greater emphasis on diagnostic approaches tailored to each organ’s or organ system’s unique aging trajectory.

Disease Management and Prevention

By deepening our understanding of the factors contributing to aging and the intricate network of multi-organ interactions, we can take crucial steps towards slowing down or reversing aging in different organs, thus mitigating the onset of age-related diseases. With this knowledge, medical professionals can attend to variations in organ biological age and, based on personalized risk factors, tailor interventions to address specific needs more effectively.

Ongoing research holds promise for successful therapies capable of restoring failing organs on an as-needed basis and implementing preventive treatments to maintain healthy organs in optimal condition.

Systems-Focused, Whole-Person Care

The latest findings contribute to our growing understanding of the underlying causes and drivers of aging and chronic disease. Earlier studies have established aging clocks for individual organs, such as the kidneys, lungs, and heart, but this is the first whole-body multi-organ characterization of the aging process. By recognizing the intricate connections between various systems in the body, and the varying rates at which they age, health professionals are better positioned to develop targeted interventions that effectively address individual patient needs.

By quantifying the influence of chronic diseases on organ aging, the healthcare community gains valuable insights with substantial promise for precision geriatric medicine and integrative care. As experts outline in a Proto.Life article, the real promise for advancement is the shift from a piecemeal approach to healthcare, or the “one doctor per organ” paradigm, to redefining health as a dynamic ecosystem of interconnected elements – and treating the patient as a whole, rather than a collection of isolated symptoms.

Such an integrated approach not only offers the potential for extended longevity but also paves the way for a future in which aging is viewed as a malleable process that can be influenced and optimized.

Further study of the multi-organ aging network and how organs compensate for each other’s aging processes is necessary to expand the clinical utility of this information and enhance our understanding of the intricate dynamics involved in aging. In the meantime, the healthcare community should prioritize spreading awareness of organ-specific aging and highlighting the need for proactive measures to maintain organ health and identify high-risk patients early on. So that patients can feel empowered to take control of their health and medical professionals can provide tailored care that addresses the interconnected organ aging process while supporting the health ecosystem as a whole.