Circadian rhythm disruption `may cause deadly diseases like cancer`
Washington: Disruptions to the circadian rhythm can affect the growth of blood vessels in the body, thus causing illnesses such as diabetes, obesity and cancer, a new study has suggested.
The circadian rhythm is regulated by a “clock” that reacts to both incoming light and genetic factors.
In the new study by researchers from Linkoping University and Karolinska Institutet, it has been demonstrated for the first time that disruption of the circadian rhythm immediately inhibit blood vessel growth in zebra fish embryos.
Professor Yihai Cao leads a research group, which has demonstrated that the breaking point is the production of a very important signalling substance: vascular endothelial growth factor (VEGF). The formation of this substance requires a normal circadian rhythm.
During experiments with hours-old zebra fish embryos, the researchers manipulated their circadian rhythm through exposing them to lighting conditions varying from constant darkness to constant light.
The growth of blood vessels in the various groups was then studied. The results showed that exposure to constant light (1800 lux) markedly impaired blood vessel growth; additionally, it affected the expression of genes that regulate the circadian clock.
“The results can definitely be translated into clinical circumstances. Individuals with disrupted circadian rhythms – for example, shift workers who work under artificial lights at night, people with sleep disorders or a genetic predisposition – should be on guard against illnesses associated with disrupted blood vessel growth,” Lasse Dahl Jensen, lead author of the study, said.
Such diseases include heart attack, stroke, chronic inflammation, and cancer. Disruptions in blood vessel growth can also affect foetal development, women’s reproductive cycles, and the healing of wounds.
The study has been published in the scientific journal Cell Reports.