A new sleep apnea study has found that snoring promotes cancer development because it limits oxygen intake.
Numerous studies have linked bad sleep to poor cancer outcomes, and this latest study reveals that hypoxia may be the reason why. Researchers in Spain explain that hypoxia, which is just one of the consequences of sleep apnea, happens when body tissues or organs don't get enough oxygen.
Intermittent hypoxia, which is a common side effect of obstructive apnea, apparently worsens cancer development by promoting blood vessel growth within tumors.
The research team found that mice subjected to intermittent hypoxia had significantly more vascular progenitor cells and endothelial cells in their tumors. Mice exposed to intermittent hypoxia also had higher circulation of vascular endothelial growth factor.
The study involved 24 mice with kidney tumors. Half of the mice were subjected to intermittent hypoxia, and the other half were used as controls.
"In the animal model, intermittent hypoxia increases the production of circulating vascular endothelial growth factor and the mobilization of vascular progenitor cells, resulting in an increased vascularization of the tumor. In vitro, isolated tumor cells do not increase vascular endothelial growth factor production under intermittent hypoxia compared to normoxia," researchers explained.
Lead researcher Antoni Vilaseca of Hospital Clínic De Barcelona said that the latest findings suggest obstructive sleep apnea promotes cancer development by increasing blood flow in tumors.
"Patients suffering from obstructive sleep apnea usually suffer from intermittent hypoxia at night. This work shows that intermittent hypoxia has the potential to promote the formation of blood vessels within tumors, meaning that the tumors have access to more nutrients," Vilaseca said in a news release.
"Although this is an experimental study, it is remarkable, because it demonstrates the influence of oxygen deficiency on the growth of renal cell carcinoma tissue (both primary tumor as well as metastases). It may be postulated that increased oxygenation of the blood may be the underlying mechanism why not smoking or giving up smoking, regular sport activity (especially endurance type sports), reducing the body mass index and other life style changes that increase tissue oxygenation have a supportive beneficial effect on better outcomes in renal cell cancer as well as other tumor types," Arnulf Stenzl, Chair of the EAU Congress Committee, said in a statement.
The findings were presented their findings at the European Association of Urology Congress in Munich.
