Abstract
Chronic jet lag alters the microenvironment surrounding tumor cells, making it more favorable for tumor growth, and also hinders the body's natural immune defenses, according to researchers in the U.S. and Argentina.
“Circadian disruption negatively affects physiology, posing a global health threat that manifests in proliferative, metabolic, and immune diseases, among others. Because outputs of the circadian clock regulate daily fluctuations in the immune response, we determined whether circadian disruption results in tumor-associated immune cell remodeling, facilitating tumor growth,” the investigators wrote.
The team examined two groups of mice that were injected with melanoma cells. The first group was exposed to a normal circadian schedule: 12 hours of light and 12 hours of dark. The second group's light and dark exposure was shifted by six hours every two days– the equivalent of roaming across 21 time zones per week. A month later, the scientists observed that the tumors in the jet lagged group were roughly three times the size of the control group.
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