Aging
Overview
Aging (Korean: 노화, Aging) is a complex biological process in which the functions of cells, tissues, organs, and the entire body of an organism gradually deteriorate over time. It is a universal phenomenon observed in all living beings, resulting from the interaction of various internal and external factors such as genetic factors, environmental stress, and accumulation of cellular metabolic byproducts. Aging involves not merely an extension of lifespan but also increased vulnerability to diseases and functional decline. Recently, the scientific community has seen a growing perspective that views aging itself as a treatable disease.
Main Content
1. Biological Mechanisms of Aging
Aging cannot be explained by a single cause; it results from the accumulation of various changes at the cellular and molecular levels. Key mechanisms include telomere shortening, accumulation of DNA damage, disruption of protein homeostasis, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, and abnormal intercellular signaling. In particular, telomeres are structures that protect chromosome ends; they shorten with each cell division, eventually leading to cell cycle arrest or cell death. Additionally, oxidative stress caused by reactive oxygen species (ROS) damages DNA, proteins, and lipids, accelerating aging.
2. Development of Aging Theories
Historically, aging has been categorized into 'programmed theories' and 'damage accumulation theories.' Programmed theories propose that genes predesign the aging process, while damage accumulation theories argue that random damage accumulates over time, leading to aging. Modern science supports a 'multifactorial theory' that integrates these two perspectives, and the 'nine hallmarks of aging' proposed by Carlos López-Otín et al. in 2013 are widely cited. These hallmarks include genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, deregulated nutrient sensing, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, and altered intercellular communication.
3. Aging-Related Diseases
Aging is a major risk factor for various chronic diseases, including cancer, cardiovascular diseases, neurodegenerative diseases (Alzheimer's disease, Parkinson's disease), type 2 diabetes, osteoporosis, and sarcopenia. These diseases are promoted by cellular functional decline and increased inflammatory responses (inflammaging) that occur during aging. In particular, immunosenescence increases susceptibility to infections and reduces vaccine efficacy.
4. Aging Research Methodologies
Aging research utilizes human epidemiological studies, animal models (Caenorhabditis elegans, Drosophila, mice, primates), cell culture models, and organoid technology. Recent advances in omics technologies, such as single-cell transcriptomics, epigenomics, proteomics, and metabolomics, have enabled a precise understanding of the aging process at the molecular level. Additionally, the concept of the aging clock has been introduced, leading to the development of methods to estimate biological age based on DNA methylation patterns.
5. Research on Delaying and Reversing Aging
Research aimed at slowing or reversing aging is actively ongoing. Caloric restriction (CR) has demonstrated lifespan-extending effects in various animal models, and candidate substances such as rapamycin, metformin, NAD+ precursors (e.g., NMN, NR), and senolytics (drugs that eliminate senescent cells) are being studied. Additionally, gene therapies (e.g., telomerase activation, transient expression of Yamanaka factors) and epigenetic reprogramming for aging reversal are attracting attention. In 2023, David Sinclair's research team successfully restored vision in mouse optic nerve cells, demonstrating the potential of epigenetic reprogramming.
Latest Trends
As of 2024-2025, aging research is rapidly entering the clinical application stage. Key trends include:
- Expansion of Senolytics Clinical Trials: Companies like Unity Biotechnology are conducting phase 2 clinical trials of senolytics for aging-related eye diseases and osteoarthritis.
- Practical Application of Aging Clocks: DNA methylation-based aging clocks are beginning to be used for personalized health management, and some companies have commercialized services for measuring biological age using blood biomarkers.
- Longevity Gene Research: Large-scale cohort studies on longevity-related gene variants such as FOXO3, SIRT1, and APOE are underway, and research on manipulating aging-related genes using gene editing technology (CRISPR) is also active.
- Relationship Between Aging and Immunity: Preclinical results have been published showing that CAR-T cell therapy targeting immunosenescence is effective in eliminating senescent cells.
- Shift Toward Healthspan Focus: The concept of 'healthspan'—extending the period of healthy life rather than merely prolonging lifespan—has emerged as a core goal of policy and research.
- AI-Based Aging Research: Artificial intelligence is being used to discover aging biomarkers, repurpose drugs, and develop predictive models of the aging process, accelerating the pace of new drug development.
Related Topics
- [[Telomere]]
- [[Caloric restriction]]
- [[Cellular senescence]]
- [[Epigenetics]]
- [[Longevity gene]]
---
AI-generated document · Community collaboration welcome