Aging and oxidatively damaged nuclear DNA in animal organs

Area of Science:

• Gerontology
• Molecular Biology
• Genetics

Background:

• Oxidative stress is linked to aging and DNA damage, specifically 8-oxo-7,8-dihydroguanine.
• Accumulation of DNA damage is a proposed mechanism contributing to the aging process.

Purpose of the Study:

• To systematically review studies measuring oxidatively damaged DNA in animal organs across different ages.
• To determine if age-associated DNA damage accumulation varies by organ type and cell proliferation rate.

Main Methods:

• Meta-analysis of 69 studies measuring oxidatively damaged DNA in animal organs.
• Analysis stratified by organ type (limited vs. high cell proliferation) and baseline DNA damage levels.
• Assessment for potential biases, including citation and publication bias.

Main Results:

• Organs with limited cell proliferation (liver, kidney, brain, heart, pancreas, muscle) generally showed age-associated DNA damage accumulation.
• Organs with high cell proliferation (intestine, spleen, testis) exhibited more variable or no age-related effects.
• A restricted analysis (baseline < 5 lesions/10^6 dG) revealed 21/29 studies showing age-associated DNA damage accumulation (SMD = 1.49).

Conclusions:

• Compelling evidence supports the accumulation of oxidatively damaged DNA with age in organs characterized by limited cell proliferation.
• Cell proliferation rate is a key factor influencing the age-dependent accumulation of DNA damage in different organs.