Five Lines of Defense: A First-Principles Framework for Healthy Aging

Abstract

Modern medicine excels at managing "already-established diseases," but the real challenge of healthy aging is identifying the breakdown of bodily systems before disease takes shape. Chronic diseases, age-related diseases, and functional decline are rarely sudden events; they accumulate gradually across five layers — phenotype, organ function, metabolic homeostasis, immune repair, and Aging Hallmarks.

In this article, "root causes of aging" refers specifically to Aging Hallmarks, including DNA damage, telomere attrition, epigenetic alterations, loss of proteostasis, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, chronic inflammation, and other foundational mechanisms. In other words, the "root cause of aging" is not a vague notion of "reasons" but rather the Hallmarks of Aging — the shared language of the international aging biology community.

This article attempts to derive, from first principles and drawing on landmark research in aging biology, epigenetic clocks, organ aging, immunosenescence, inflammaging, and metabolic imbalance, a framework applicable to public health management, disease prevention, and anti-aging practice:

> Five Lines of Defense for healthy aging.

Put more directly: Disease is not sudden; it is the result of capacity reserve progressively collapsing along five lines of defense.

These five lines of defense are:

1. Phenotypic Early Warning Line

2. Organ Function Line

3. Metabolic Homeostasis Line

4. Immune Repair Line

5. Aging Hallmarks Line

This is not an arbitrary marketing framework but a defense system naturally derived from Dr. Xiong Jianghui's first principle that "life is a collection of capacities to adapt to the environment." Its significance lies in shifting anti-aging from "post-hoc repair" to "capacity reserve management," and transforming disease prevention from vague generalities into a long-term healthy aging pathway that is warnable, detectable, modelable, intervenable, and re-testable.

I. The Starting Question: Why Shouldn't We Begin Understanding Disease Only on the Day of Diagnosis?

Clinical medicine is typically diagnosis-centered: when symptoms, imaging, pathology, or laboratory markers reach a certain threshold, a person is defined as "having a disease."

But from the perspective of a living system, disease does not begin on the day of diagnosis. Diagnosis is merely the clinical manifestation of disease. Long before structural lesions appear, the body has often already undergone prolonged decline in functional reserve, metabolic imbalance, immune dysregulation, chronic inflammation, cellular damage, and accumulation of Aging Hallmarks.

Take diabetes, cardiovascular disease, cancer, neurodegenerative disease, chronic kidney disease, and sarcopenia as examples — they are rarely sudden acute events but rather the consequences of long-term systemic imbalance.

Therefore, the core question of health management should not merely be:

> Do I have a disease right now?

It should shift to:

> Where is my body heading? Which line of defense is collapsing? How much time window do I have left for intervention?

This is precisely the question that the Five Lines of Defense for healthy aging seeks to answer.

II. The First Principle: Life Is a Collection of Capacities to Adapt to the Environment

In his "Prologue: The 'Theoretical Physics Moment' of Biomedicine," Dr. Xiong Jianghui offers a first principle of life:

> Life is a collection of capacities to adapt to the environment.

The key to this statement lies not in "what life is made of" but in "how life persists." Life is not a static assemblage of proteins, DNA, and cells; if we look only at structure, there is no fundamental material difference between a corpse and a living person. What makes life alive is its capacity to continuously gather information, process stress, regulate state, repair damage, maintain order, and resist entropy increase in a dynamic environment.

Building on this first principle, Dr. Xiong further proposes:

> Capacity Reserve is the ultimate metric of health.

This means that health is not merely "structures haven't broken yet," nor simply "some indicator is still within the normal range." Health is the body's retention of sufficient adaptive capacity, repair capacity, and systemic reserve when facing nutritional fluctuations, stress, pathogens, inflammation, injury, and the accumulation of time.

From this first principle, the logic of anti-aging and disease prevention can be compressed into a deductive chain:

> Life = a collection of capacities to adapt to the environment;

> Health = capacity reserve that is sufficient and deployable;

> Aging = capacity reserve being depleted, mismatched, and losing control over time;

> Disease = the clinical manifestation after capacity reserve drops below a certain functional threshold;

> Therefore, anti-aging and disease prevention = continuously monitoring and repairing capacity reserve before disease becomes clinically manifest.

The question then becomes very clear: if the essence of health is not structure but capacity reserve, we cannot simply wait for structures to break before acting. We must set up key checkpoints before capacity reserve is exhausted. The Five Lines of Defense are precisely inspections of five essential dimensions of the body's capacity reserve.

1. Have Changes in Capacity Already Manifested in the External Phenotype?

Declines in the internal capacity of a living system tend to project onto the external phenotype first. Complexion, hair, facial expression, mood, vitality, sleep, and resilience are all outward signals of changes in the body's adaptive capacity.

When a person experiences chronic fatigue, worsening complexion, slower recovery, emotional fluctuations, or declining vitality, these phenomena do not necessarily equal disease, but they are very likely early warnings of declining capacity reserve.

2. Do the Organs That Execute Life Functions Still Have Reserve?

Life's activities are ultimately executed by organs. The heart, liver, kidneys, brain, lungs, skeletal muscle, and blood vessels serve as both structural and functional units. By the time disease enters the organ structural level, it is often already quite late.

Therefore, anti-aging and disease prevention must focus on whether organ functional reserve is declining before significant structural damage occurs.

3. Can the Metabolic System Still Maintain Dynamic Homeostasis?

Adapting to the environment requires energy. The human body is a system that continuously performs energy conversion, material exchange, and signal regulation. Blood glucose, blood lipids, insulin sensitivity, mitochondrial function, oxidative stress, nutritional status, and inflammatory metabolism determine whether the body is in an efficient, low-damage, recoverable state.

The collapse of metabolic homeostasis is essentially a decline in the energy-adaptive capacity of the living system.

4. Can the Immune System Still Defend, Clear, and Repair?

Adapting to the environment also means identifying threats, eliminating abnormalities, and repairing damage. The immune system does more than resist infection — it is also responsible for clearing abnormal cells, processing damage signals, regulating inflammatory responses, and participating in tissue repair.

With age, declining immune surveillance coexists with chronic low-grade inflammation, creating the dual problem of "immunosenescence" and "inflammaging." This reduces the living system's capacity to adapt to external stress and internal damage.

5. Are Foundational Aging Hallmarks Consuming Capacity Reserve?

The "root causes of aging" discussed in this article refer specifically to Aging Hallmarks. These include a set of foundational mechanisms repeatedly discussed in aging biology: epigenetic alterations, DNA damage, telomere attrition, mitochondrial decline, cellular senescence, loss of proteostasis, chronic inflammation, stem cell exhaustion, and more.

If these Hallmarks continue to accumulate, phenotype, organs, metabolism, and immunity will all be dragged into a downward trajectory. Only by detecting Hallmarks do we truly touch the foundation of aging; looking only at symptoms and organs often means we are already standing downstream of disease formation.

It is thus evident that the Five Lines of Defense for healthy aging are not artificially stitched together but naturally derived from the first principle that "life is a collection of capacities to adapt to the environment." The essence of health management is precisely what Root-Cause Medicine advocates: to monitor, model, and repair the capacity reserve of the living system.

III. Evidence from Landmark Studies: Aging Is Multi-Level Systemic Collapse

1. Aging Is Not a Single Indicator but an Interconnected Network of Root Causes

In 2013, López-Otín and colleagues published the classic review "The Hallmarks of Aging" in Cell, proposing nine hallmarks of aging: genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, deregulated nutrient sensing, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, and altered intercellular communication.

In 2023, this framework was further expanded in Cell to twelve aging hallmarks, adding chronic inflammation, gut microbiota dysbiosis, and disabled autophagy. The core idea is that aging is not any single organ, single indicator, or single disease, but a systemic imbalance driven by multi-level biological processes.

This provides the theoretical foundation for the "Aging Hallmarks Line." The so-called root cause is not a disease name, but the shared foundational mechanism that simultaneously drives multiple organs, metabolic systems, and immune systems to age.

2. Biological Age Can Be Measured and Correlates with Disease and Mortality Risk

In research on DNA methylation age published in Genome Biology, Horvath proposed an epigenetic clock based on 353 CpG sites, demonstrating that DNA methylation patterns can be used to estimate the biological age of different tissue and cell types.

Subsequent studies such as DNAm PhenoAge further showed that epigenetic age not only reflects chronological age but also correlates with multimorbidity, coronary heart disease risk, physical function decline, all-cause mortality, cancer, Alzheimer's disease, and other health outcomes.

This demonstrates that "root causes of aging" are not abstract concepts but can be quantified through DNA methylation, epigenetic clocks, biological age, and multi-dimensional biomarkers.

3. Each Organ Has Its Own Rate of Aging

A 2023 study published in Nature on plasma proteome organ aging showed that different organs can exhibit different organ aging molecular age trajectories, and that organ-specific aging signals correlate with disease risk and mortality risk.

This means that a person's overall age cannot represent the state of all organs. Some people may have "a fast-aging heart," others "fast-aging kidneys," and still others may have "a brain or immune system that ages quickly."

This provides the basis for the "Organ Function Line": anti-aging and disease prevention cannot look only at overall age but must examine the functional reserve and aging trajectory of specific organs.

4. Metabolic Imbalance Is the Common Upstream of Chronic Disease and Aging

Metabolic problems are not simply blood glucose or lipid abnormalities. Insulin resistance, chronic inflammation, lipotoxicity, mitochondrial decline, deregulated nutrient sensing, and oxidative stress together constitute the common soil for many chronic diseases.

Insulin resistance can exist for years before type 2 diabetes manifests and is closely linked to hypertension, dyslipidemia, fatty liver, inflammation, and vascular dysfunction. The "deregulated nutrient sensing" and "mitochondrial dysfunction" identified in aging biology also point to the foundational role of the metabolic system in healthy aging.

This demonstrates that the "Metabolic Homeostasis Line" is one of the most important intermediate battlegrounds for disease prevention.

5. Immune Aging May Be a Driver of Systemic Aging

The inflammaging concept proposed by Franceschi emphasizes that the aging process gives rise to a chronic, low-grade, sterile inflammatory state. Immunosenescence manifests as a decline in immune surveillance, immune response, and repair capacity.

More importantly, immunosenescence is not merely a consequence of aging but may also become a driver of systemic aging.

A 2021 paper published in Nature, "An aged immune system drives senescence and ageing of solid organs," demonstrated that an aged immune system has a causal role in driving cellular senescence in solid organs and systemic aging. In the study, transferring immune cells from aged or progeroid models into young mice induced senescence phenotypes in recipients; conversely, young immune cells could alleviate senescence-related phenotypes. This demonstrates that the immune system is not a passive bystander in aging but potentially a critical upstream driver of systemic aging.

A more recent review published in Nature Reviews Immunology, "The ageing immune system as a driver of systemic ageing," further elevates this direction into a systematic proposition: the aging immune system can drive multi-organ dysfunction and systemic aging, and improving immune function may become an important strategy for extending healthspan.

This provides a stronger theoretical foundation for the "Immune Repair Line": if immune aging can drive systemic aging, then anti-aging and disease prevention cannot focus only on metabolic or organ indicators but must place immune repair capacity at the core of the defense system.

IV. Deriving the Five Lines of Defense from First Principles

If life is a collection of capacities to adapt to the environment, then disease and aging are not simply "structural damage" but the process by which capacity reserve is progressively depleted, mismatched, and loses control under time, environment, and stress.

Therefore, a sound framework for anti-aging and disease prevention cannot merely ask "what is broken" but must interrogate "which capacity is collapsing." Thus, the Five Lines of Defense are not five parallel test items but five checkpoints of the body's capacity reserve, from the externally manifest to the innermost core.

Question One: Has the Body Already Sent External Warning Signals?

This corresponds to the first line of defense:

Line One: Phenotypic Early Warning Line

Phenotypic early warning includes:

- Worsening complexion;

- Deteriorating hair;

- Fatigued facial expression;

- Emotional fluctuations;

- Declining vitality;

- Worsening sleep;

- Slower recovery;

- Chronic fatigue.

These are not diagnostic conclusions, but they are forward sentinels.

What many people first notice is not an abnormal laboratory indicator, but:

> I've been recovering more slowly lately.

> I look lackluster.

> I'm clearly not sick, but I'm getting more and more tired.

> My mood and sleep are becoming increasingly unstable.

These signals tell us that one or more layers of defense inside the body may have already shifted.

So the role of the first line of defense is not to diagnose, but to provide early warning.

> Phenotype is not disease, but phenotype may be the first intelligence report the body issues before disease forms.

Question Two: Are the Organs That Execute Life Functions Beginning to Lose Reserve?

This corresponds to the second line of defense:

Line Two: Organ Function Line

Organs are the hardware positions of the living system. Traditional physical examinations and clinical diagnoses often intervene only when clear structural abnormalities appear in organs, but healthy aging requires attention to the early decline of organ functional reserve.

This line of defense focuses on:

- Liver and kidney function;

- Cardiovascular function;

- Skeletal muscle status;

- Nervous system function;

- Organ reserve capacity;

- Trends in organ function decline.

This layer answers:

> Is my body's hardware already beginning to weaken?

If organ functional reserve continues to decline, even if it has not yet reached the threshold for disease diagnosis, the body will be more susceptible to entering a disease state in the future.

Question Three: Is the Body's Energy and Material Exchange Stable?

This corresponds to the third line of defense:

Line Three: Metabolic Homeostasis Line

Metabolism is the body's supply line. Blood glucose, blood lipids, insulin sensitivity, inflammatory metabolism, oxidative stress, mitochondrial function, and nutritional status together determine whether the body has sufficient energy, low damage, and good recovery capacity.

This line of defense focuses on:

- Glucose and lipid metabolism;

- Insulin sensitivity;

- Inflammatory metabolism;

- Oxidative stress;

- Mitochondrial function;

- Nutritional status;

- Body weight and energy balance.

Many chronic diseases do not arrive suddenly but are dragged out by long-term collapse of metabolic homeostasis.

> Metabolism is not a single indicator but the foundational capacity of the body to sustain low-damage operation.

Question Four: Is the Body's Defense and Repair System Still Effective?

This corresponds to the fourth line of defense:

Line Four: Immune Repair Line

The immune system is the body's military and its repair crew. It is responsible not only for resisting foreign pathogens but also for clearing abnormal cells, processing tissue damage, regulating inflammatory responses, and maintaining internal homeostasis.

This line of defense focuses on:

- Chronic low-grade inflammation;

- Immune surveillance;

- Immune clearance;

- Resistance to infection;

- Clearance of abnormal cells;

- Tissue repair capacity;

- Inflammation control capacity.

With age, the most dangerous thing is not that the immune system simply "weakens" but that a paradoxical state emerges:

> On one hand, immune surveillance and repair capacity decline;

> On the other hand, the chronic inflammatory background continues to rise.

This is the combined risk posed by immunosenescence and inflammaging.

Question Five: Are the Foundational Mechanisms Driving Systemic Aging Being Activated?

This corresponds to the fifth line of defense:

Line Five: Aging Hallmarks Line

This layer does not look at any single symptom or any single organ, but at whether the foundational mechanisms driving the overall aging of the body are accelerating. The "root causes of aging" in this article refer specifically to Aging Hallmarks, not to generalized lifestyle causes or single disease triggers.

This line of defense focuses on:

- DNA methylation and epigenetic drift;

- Biological age and epigenetic clocks;

- Genomic instability and DNA damage repair;

- Telomere attrition;

- Loss of proteostasis;

- Decline in autophagy;

- Deregulated nutrient sensing;

- Mitochondrial dysfunction;

- Cellular senescence;

- Stem cell exhaustion;

- Altered intercellular communication;

- Chronic inflammation and immune aging;

- Gut microbiota dysbiosis and other systemic aging mechanisms.

True anti-aging is not merely looking young on the surface but identifying and defending against the Hallmarks that drive the body's systemic aging.

> If Aging Hallmarks continue to accelerate, phenotype, organs, metabolism, and immunity will all be dragged into a downward trajectory; the key to anti-aging is not covering up the surface of aging but holding the foundation of aging.

V. Why "Five Lines of Defense" Instead of a Single Composite Score?

Because the living system is not a single-layer structure, and capacity reserve is not a single variable.

A composite score may be convenient to display, but it tends to flatten problems at different levels: phenotypic early warning, organ reserve, metabolic homeostasis, immune repair, and aging root causes are interrelated yet represent fundamentally different capacities. Truly valuable health management must distinguish clearly:

- Has the phenotype issued a warning?

- Is organ functional reserve declining?

- Has metabolic homeostasis collapsed?

- Has immune repair capacity declined?

- Are aging root causes accelerating?

These five questions correspond to different intervention logics.

For example:

- If phenotypic warning is prominent but indicators are not yet severely abnormal, it indicates the need to enter testing and lifestyle intervention as early as possible;

- If metabolic homeostasis has collapsed, priority should be given to repairing diet, exercise, sleep, body weight, insulin sensitivity, and inflammatory metabolism;

- If the immune repair line has declined, the focus should be on chronic inflammation, infection burden, gut status, nutrition, and resilience;

- If Aging Hallmarks are accelerating, long-term management should center on DNA methylation, epigenetic clocks, mitochondrial function, cellular senescence, telomere attrition, proteostasis, autophagy, chronic inflammation, and biological age;

- If organ function is declining, it is necessary to determine which organ system is losing reserve first and to enter professional medical evaluation promptly.

Therefore, the Five Lines of Defense exist not to complicate things but to move health management from "generic advice" into a closed loop of "localize — model — intervene — re-test."

VI. The Fortress Model of the Five Lines of Defense

We can understand this through the metaphor of defending an ancient fortress.

Traditional medicine often begins street fighting only after the enemy has already breached the city gates.

The Five Lines of Defense for healthy aging, by contrast, sets up multiple interception lines outside the city walls.

| Fortress Metaphor | Five Lines of Defense | Function |

| --- | --- | --- |

| Outfield scouts | Phenotypic Early Warning Line | Earliest detection of threats |

| Outer fortifications | Organ Function Line | Assessing whether the main position is weakening |

| Supply lines | Metabolic Homeostasis Line | Ensuring energy and material supply |

| City garrison | Immune Repair Line | Clearing abnormalities, repairing damage |

| Fortress foundation | Aging Hallmarks Line | Determining long-term combat power and structural stability |

This metaphor illustrates the core value of the Five Lines of Defense:

> The earlier a line-of-defense collapse is detected, the more time there is to mobilize troops, repair walls, resupply, and counterattack.

Healthy aging is not about making amends after growing old, but about continuously repairing the body's defenses over the decades before disease forms.

VII. Capome and SteeraMed: From Framework to Practice

A theoretical framework becomes truly meaningful only when it enters practice.

The practical pathway for the Five Lines of Defense for healthy aging can be divided into three layers.

1. Capome: A Panoramic Aging and Intrinsic Capacity Assessment System

The value of Capome, the panoramic aging and intrinsic capacity assessment system (developed by Deep Methylation), lies not in "having many items" but in its ability to map the body's state onto the Five Lines of Defense.

Specifically:

- The Phenotypic Early Warning Line draws from outward signals such as complexion, hair, mood, facial expression, vitality, sleep, fatigue, and resilience;

- The Organ Function Line corresponds to indicators related to organ function and reserve capacity;

- The Metabolic Homeostasis Line corresponds to indicators related to glucose and lipid metabolism, inflammatory metabolism, nutritional status, oxidative stress, and energy metabolism;

- The Immune Repair Line corresponds to indicators related to immune status, chronic inflammation, tissue repair, and immune surveillance;

- The Aging Hallmarks Line corresponds to foundational mechanisms such as DNA methylation, biological age, epigenetic alterations, telomere attrition, mitochondrial dysfunction, cellular senescence, loss of proteostasis, chronic inflammation, and stem cell exhaustion.

Therefore, Capome is not an ordinary physical examination but the observation layer of the Five Lines of Defense for healthy aging, based on Capomics (Capacity Omics).

2. SteeraMed: The World Model and Command System for the Five Lines of Defense

Detection is only the first step. What is truly difficult is interpretation:

- Which line of defense is collapsing?

- What causal or network connections exist among indicators?

- Which problem is upstream?

- Which problem is merely a downstream manifestation?

- Along which trajectory might disease risk develop?

- Which line of defense should be repaired first?

- How should re-testing and calibration be conducted after intervention?

This is precisely the value of the SteeraMed Steerable World Model.

If Capome is responsible for seeing the defense lines, SteeraMed is responsible for judging the trajectory of defense collapse and repair priorities.

3. Re-Testing: Turning Anti-Aging into a Closed Loop

Without re-testing, there is no true health management.

The purpose of re-testing is not to repeat examinations but to verify whether intervention has changed the trajectory.

The true closed loop should be:

> Phenotypic early warning → Five Lines of Defense testing → World model modeling → Personalized intervention → Re-test calibration → Long-term healthy aging management.

The communicable expression of this pathway can be even shorter: Capome sees the defense lines, SteeraMed commands the repair; a single test is not the endpoint but the starting point of long-term fortress defense.

VIII. The True Value of the Five Lines of Defense: Gaining an Optimization Window Decades in Advance

Many people wait until a disease is diagnosed before taking action.

But by then, the disease has often already crossed multiple defense lines and entered the stage of structural change or clinical pathology.

The value of the Five Lines of Defense for healthy aging is not about doing one more test, but about gaining time in advance.

> Others begin dealing with disease only after it is diagnosed; the significance of the Five Lines of Defense is that it allows us to start optimizing the body's state 10, 20, or even more years before disease forms.

This is precisely the essence of healthy aging.

Healthy aging is not about pursuing "never aging," nor is it about pursuing indefinite life extension. It is about keeping a person, for as long as possible:

- Functionally intact;

- Energetically sufficient;

- Metabolically stable;

- Immunologically effective;

- With adequate organ reserve;

- With controllable aging rate;

- With diseases occurring later, less frequently, and more mildly.

IX. From the Diagnostic Paradigm to the Pre-Disease Interception Paradigm

The basic pathway of traditional medicine is:

> Symptoms appear → Examination → Diagnosis → Treatment.

The Five Lines of Defense for healthy aging represents a different pathway:

> Phenotypic early warning → Defense line inspection → State modeling → Risk projection → Targeted repair → Re-test calibration.

This is not intended to replace clinical medicine but to fill the vast gap that exists before clinical medicine.

If clinical medicine deals with "enemies that have already breached the city gates," then the Five Lines of Defense for healthy aging deals with "intelligence, deployment, and interception when the enemy is still massing outside the walls."

This is the direction of future health management:

> Not treating disease after it appears, but identifying defense collapse before disease forms and continuously repairing the body's systems.

X. Conclusion: The Five Lines of Defense as the Minimum Complete Framework for Anti-Aging and Disease Prevention

From the first principle that "life is a collection of capacities to adapt to the environment," healthy aging requires simultaneously maintaining at least five categories of capacity reserve:

1. Phenotypic expression capacity must not continuously sound alarms;

2. Organ execution capacity must not lose reserve prematurely;

3. Metabolic energy supply capacity must not remain in chronic imbalance;

4. Immune repair capacity must not fall into inefficiency and chronic inflammation;

5. Aging Hallmarks control capacity must not remain in chronic dysregulation.

Therefore, the Five Lines of Defense for healthy aging is not an arbitrarily proposed slogan but the minimum complete framework for healthy aging. It places aging biology, disease prevention, phenotypic early warning, methylation testing, world model modeling, and personalized intervention within a single explainable system.

It can ultimately be distilled into a single statement:

> Disease is not sudden but the result of life's capacity reserve progressively collapsing along five lines of defense; the key to anti-aging and disease prevention is not waiting for disease to appear but continuously inspecting, modeling, and repairing these five categories of capacity reserve before disease forms.

References and Further Reading

1. DeepOMe. Aging Hallmarks: A Systematic Framework from Nine to Twelve Hallmarks.

DeepOMe Aging Hallmarks Framework

2. DeepOMe. Capome Multi-Dimensional Aging Assessment: Direct Detection of Aging Biomarkers and the Capomics Framework.

Capome Multi-Dimensional Aging Assessment

3. DeepOMe. Biological Age: DNA Methylation Clocks and Biological Age Assessment.

DeepOMe Biological Age Assessment

4. DeepOMe. Root-Cause Medicine Methodology: From the Symptom Layer and Functional Layer to the Causal Layer.

DeepOMe Root-Cause Medicine Methodology

5. DeepOMe. Glossary: Key Terms Including DNA Methylation, Epigenetic Clocks, Biological Age, and Biomarkers.

DeepOMe Glossary

6. López-Otín C, Blasco MA, Partridge L, Serrano M, Kroemer G. The Hallmarks of Aging. Cell. 2013.

"The Hallmarks of Aging", Cell, 2013

7. López-Otín C, Blasco MA, Partridge L, Serrano M, Kroemer G. Hallmarks of aging: An expanding universe. Cell. 2023.

"Hallmarks of Aging: An Expanding Universe", Cell, 2023

8. Horvath S. DNA methylation age of human tissues and cell types. Genome Biology. 2013.

"DNA Methylation Age of Human Tissues", Genome Biology, 2013

9. Levine ME et al. An epigenetic biomarker of aging for lifespan and healthspan. Aging. 2018.

"An Epigenetic Biomarker of Aging (PhenoAge)", Aging, 2018

10. Oh HS et al. Organ aging signatures in the plasma proteome track health and disease. Nature. 2023.

"Organ Aging Signatures in the Plasma Proteome", Nature, 2023

11. Franceschi C. et al. Immunology of Aging: the Birth of Inflammaging.

"Immunology of Aging: Birth of Inflammaging"

12. Yousefzadeh MJ et al. An aged immune system drives senescence and ageing of solid organs. Nature. 2021.

"An Aged Immune System Drives Senescence of Solid Organs", Nature, 2021

13. Fulop T. et al. Immunosenescence and inflammaging in the aging process: age-related diseases or longevity?

"Immunosenescence and Inflammaging in the Aging Process"

14. Park MH, Kim DH, Lee EK, Kim ND, Im DS, Lee J, Yu BP, Chung HY. Age-related inflammation and insulin resistance: a review of their intricate interdependency. Archives of Pharmacal Research. 2014;37(12):1507-1514.

"Age-related Inflammation and Insulin Resistance", Arch Pharm Res, 2014

15. Furrer R, Handschin C. Biomarkers of aging: from molecules and surrogates to physiology and function. Physiological Reviews. 2025;105(3):1609-1694.

"Biomarkers of Aging: From Molecules to Physiology", Physiol Rev, 2025

16. Jang IH, Niedernhofer LJ, Robbins PD, Camell CD. The ageing immune system as a driver of systemic ageing. Nature Reviews Immunology. 2026.

"The Ageing Immune System as a Driver of Systemic Ageing", Nat Rev Immunol, 2026