Many factors can negatively impact cell health and function. These range from physical damage to genetic abnormalities and external environmental stressors.
Physical Damage
Heat and Radiation
Physical agents like excessive heat or radiation can severely damage cells. High temperatures essentially "cook" cell contents, while radiation can cause irreparable damage to cellular structures, including DNA. This is evident in sunburns caused by ultraviolet (UV) radiation, which damages skin cell DNA and is a leading cause of skin cancer [American Cancer Society, Does UV Radiation Cause Cancer?].
Nutrient Deprivation and Energy Failure
Insufficient nutrient supply, such as a lack of oxygen (hypoxia) or glucose, directly impacts cell survival. Cells need these materials for basic metabolic functions. Furthermore, impaired production of adenosine triphosphate (ATP), the cell's primary energy source, leads to cellular dysfunction and eventual death. This is highlighted by research demonstrating that the SARS-CoV-2 virus can cause lasting damage to mitochondrial energy production [NIH, SARS-CoV-2 can cause lasting damage to cells' energy production].
Genetic Abnormalities
The presence of certain genetic elements within cells plays a critical role in cancer development. Malignant cells arise due to genetic mutations that disrupt normal cell regulation and growth control [Harvard Stem Cell Institute, “Good” cells can go “bad” in a “bad neighborhood"]. Normal cells possess DNA repair mechanisms; however, extensive damage can overwhelm these systems, leading to cell death or uncontrolled proliferation. [Cancer Research UK, Cancer cells]
Environmental Factors
Exposure to certain environmental factors can negatively influence cell health. For example, prolonged exposure to blue light can damage retinal cells and potentially impair vision [UC Davis Health, How blue light affects your eyes, sleep, and health]. While the long-term effects of radiofrequency radiation from cell phones are still being researched, there is currently no clear evidence linking it to significant health problems [NCI, Cell Phones and Cancer Risk Fact Sheet]. Additionally, a "bad neighborhood" of cells can influence the health of otherwise healthy cells [Harvard Stem Cell Institute, “Good” cells can go “bad” in a “bad neighborhood"].
Cellular Senescence
While not inherently "bad," senescent cells—cells that have stopped dividing but haven't died—can contribute to issues. These cells can release molecules that cause inflammation and damage to surrounding cells [NIA, Does cellular senescence hold secrets for healthier aging?].
Contamination
Cell lines used in research can become contaminated, impacting the reliability of study results [AAAS, Bad Cells. So Many Bad Cells].
