Pathophysiology
II-29. Organ-level manifestations of the aging syndrome
老化症候群の臓器レベルの症状
Altered Intercellular Communication
- Cells communicate via hormones, metabolites, chemokines, cytokines — disturbed with aging
- Hormonal changes: ↓circulating IGF-1 (anabolic, cardioprotective, important for brain health) → brain + cardiovascular aging; sex-hormone changes
- Niche changes → stem cell exhaustion
- Senescence → inflamm-aging (chronic, low-grade inflammation of advanced age)
- Metabolic deregulation
Hallmarks of Aging (recap)
- Molecular: genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, deregulated nutrient sensing
- Cellular: mitochondrial dysfunction, cellular senescence, stem cell exhaustion, altered intercellular communication
Role in Chronic Age-Related Diseases (organ level)
- CNS: cognitive impairment, dementia, Alzheimer’s, Parkinson’s, gait/balance disorders
- Cardiovascular: atherosclerosis, stroke, AMI, heart failure, arrhythmias (vascular aging)
- Lungs: ↓FEV1, ↓VC
- Liver: insufficiency
- Kidney: ↓GFR, ↓RPF
- Skeletal muscle: sarcopenia
- Skin: ↓wound healing
- GI: reflux, ↓digestion/motility, malignancies
- Musculoskeletal: osteoporosis, arthritis
- Endocrine: menopause, ↓fertility; Pancreas: ↓exo/endocrine function (diabetes)
- Immune: immunosenescence, malignancies, anemia
- Special senses: hearing loss/tinnitus; presbyopia, AMD
- Future of medicine: target the aging process itself rather than individual diseases
一問一答
▶How is intercellular communication altered with aging?
Communication via hormones, metabolites, chemokines, and cytokines becomes disturbed, including hormonal changes, niche changes, inflamm-aging, and metabolic deregulation.
▶What is the consequence of declining IGF-1 in aging?
IGF-1 is anabolic, cardioprotective, and important for brain health, so its decline contributes to brain and cardiovascular aging.
▶What is inflamm-aging?
The chronic, low-grade inflammation of advanced age driven by accumulating senescent cells.
▶What CNS diseases are associated with aging?
Cognitive impairment, dementia, Alzheimer's, Parkinson's, and gait/balance disorders.
▶What cardiovascular diseases result from vascular aging?
Atherosclerosis, stroke, AMI, heart failure, and arrhythmias.
▶How does aging affect lung function tests?
Decreased FEV1 and decreased vital capacity (VC).
▶How does aging affect renal function?
Decreased GFR and decreased renal plasma flow (RPF).
▶What is sarcopenia?
Age-related loss of skeletal muscle mass and function.
▶What GI changes occur with aging?
Reflux, decreased digestion/motility, and increased malignancies.
▶What musculoskeletal diseases are linked to aging?
Osteoporosis and arthritis.
▶What endocrine/pancreatic changes occur with aging?
Menopause and reduced fertility; reduced pancreatic exocrine/endocrine function (diabetes).
▶What is immunosenescence?
Age-related decline of immune function, associated with increased malignancies and anemia.
▶What special-sense disorders are associated with aging?
Hearing loss/tinnitus; presbyopia and age-related macular degeneration (AMD).
▶How does aging affect the liver and skin at the organ level?
Liver insufficiency and reduced skin wound healing.
▶What is the proposed 'future of medicine' approach to aging?
Targeting the aging process itself rather than individual age-related diseases.
▶How do niche changes contribute to organ-level aging?
Aging of the stem cell niche promotes stem cell exhaustion, impairing tissue regeneration.
▶Which signaling molecules mediate intercellular communication that is disturbed in aging?
Hormones, metabolites, chemokines, and cytokines.
▶How does aging affect the pancreas specifically?
Reduced exocrine and endocrine function, contributing to diabetes.
▶How does senescence link to organ-level inflamm-aging?
Accumulated senescent cells secrete inflammatory signals that produce the chronic low-grade inflammation underlying many age-related organ diseases.
▶What hematologic change is a recognized organ-level consequence of aging?
Anemia, related to immunosenescence and reduced marrow/erythropoietic reserve.