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Credit: NHLBI
MANCHESTER—Preclinical research indicates that circadian disruption has severe adverse effects on red blood cells (RBCs), a finding that might possibly explain the high incidence of heart disease observed in shift workers.
The study also showed the negative effects could be reduced under hypoxic conditions. Hypoxia in combination with circadian disruption produced fresh RBCs.
And this, according to researchers, suggests blood donations might help decrease the risk of cardiovascular disease in shift workers.
This research was presented at the 2014 Annual Main Meeting of the Society for Experimental Biology (SEB). It was also published in Chronobiology International.
The researchers, led by Margit Egg, PhD, of the University of Innsbruck in Austria, set out to investigate the impact of circadian disruption on hypoxic signaling and the cardiovascular system.
The team used zebrafish, a model organism that, like humans, is active during the day. To disrupt circadian rhythms, the researchers subjected the fish to alternate short days (7 hours) and long days (21 hours), resembling shift patterns common in industry.
Results showed that circadian disruption increased the number of aged RBCs that accumulated in the blood vessels.
“Normally, there is a balance between newly produced red blood cells and old ones which are removed from the blood,” Dr Egg noted.
Old cells are less flexible and become stuck in the spleen and liver, where they are engulfed by white blood cells. Circadian disruption appears to inhibit this removal process, but the researchers are unsure why this is the case.
They do know that having large aggregates of old RBCs in the vessels increases the chance of a clot that could lead to a heart attack. This may explain why shift workers have a 30% higher risk of cardiovascular disease. In addition, the decreased functionality of the aged cells reduces the oxygen-carrying capacity of the blood.
However, the researchers also found that zebrafish were less affected by circadian disruption if they were simultaneously exposed to hypoxic conditions. This is because hypoxia stimulates the production of fresh RBCs.
The team noted that the cell signaling pathways that regulate circadian rhythms and the hypoxic response are intrinsically linked. This is based on the observation that genes activated by hypoxia, such as erythropoietin, normally show a daily rhythm of activity that becomes disturbed under hypoxic conditions.
“In zebrafish, hypoxia in combination with jetlag led to the production of fresh red blood cells, counteracting the harmful consequences of jetlag and reducing mortality by 10%,” Dr Egg noted.
“Blood donations in humans also stimulate the generation of new fresh erythrocytes. Therefore, blood donations on a regular basis might be a very simple measure to help decrease the cardiovascular risk in human shift workers.”
Dr Egg and her colleagues are currently investigating whether circadian disruption affects any other physiological processes, apart from the cardiovascular system. 
Credit: NHLBI
MANCHESTER—Preclinical research indicates that circadian disruption has severe adverse effects on red blood cells (RBCs), a finding that might possibly explain the high incidence of heart disease observed in shift workers.
The study also showed the negative effects could be reduced under hypoxic conditions. Hypoxia in combination with circadian disruption produced fresh RBCs.
And this, according to researchers, suggests blood donations might help decrease the risk of cardiovascular disease in shift workers.
This research was presented at the 2014 Annual Main Meeting of the Society for Experimental Biology (SEB). It was also published in Chronobiology International.
The researchers, led by Margit Egg, PhD, of the University of Innsbruck in Austria, set out to investigate the impact of circadian disruption on hypoxic signaling and the cardiovascular system.
The team used zebrafish, a model organism that, like humans, is active during the day. To disrupt circadian rhythms, the researchers subjected the fish to alternate short days (7 hours) and long days (21 hours), resembling shift patterns common in industry.
Results showed that circadian disruption increased the number of aged RBCs that accumulated in the blood vessels.
“Normally, there is a balance between newly produced red blood cells and old ones which are removed from the blood,” Dr Egg noted.
Old cells are less flexible and become stuck in the spleen and liver, where they are engulfed by white blood cells. Circadian disruption appears to inhibit this removal process, but the researchers are unsure why this is the case.
They do know that having large aggregates of old RBCs in the vessels increases the chance of a clot that could lead to a heart attack. This may explain why shift workers have a 30% higher risk of cardiovascular disease. In addition, the decreased functionality of the aged cells reduces the oxygen-carrying capacity of the blood.
However, the researchers also found that zebrafish were less affected by circadian disruption if they were simultaneously exposed to hypoxic conditions. This is because hypoxia stimulates the production of fresh RBCs.
The team noted that the cell signaling pathways that regulate circadian rhythms and the hypoxic response are intrinsically linked. This is based on the observation that genes activated by hypoxia, such as erythropoietin, normally show a daily rhythm of activity that becomes disturbed under hypoxic conditions.
“In zebrafish, hypoxia in combination with jetlag led to the production of fresh red blood cells, counteracting the harmful consequences of jetlag and reducing mortality by 10%,” Dr Egg noted.
“Blood donations in humans also stimulate the generation of new fresh erythrocytes. Therefore, blood donations on a regular basis might be a very simple measure to help decrease the cardiovascular risk in human shift workers.”
Dr Egg and her colleagues are currently investigating whether circadian disruption affects any other physiological processes, apart from the cardiovascular system.
Credit: NHLBI
MANCHESTER—Preclinical research indicates that circadian disruption has severe adverse effects on red blood cells (RBCs), a finding that might possibly explain the high incidence of heart disease observed in shift workers.
The study also showed the negative effects could be reduced under hypoxic conditions. Hypoxia in combination with circadian disruption produced fresh RBCs.
And this, according to researchers, suggests blood donations might help decrease the risk of cardiovascular disease in shift workers.
This research was presented at the 2014 Annual Main Meeting of the Society for Experimental Biology (SEB). It was also published in Chronobiology International.
The researchers, led by Margit Egg, PhD, of the University of Innsbruck in Austria, set out to investigate the impact of circadian disruption on hypoxic signaling and the cardiovascular system.
The team used zebrafish, a model organism that, like humans, is active during the day. To disrupt circadian rhythms, the researchers subjected the fish to alternate short days (7 hours) and long days (21 hours), resembling shift patterns common in industry.
Results showed that circadian disruption increased the number of aged RBCs that accumulated in the blood vessels.
“Normally, there is a balance between newly produced red blood cells and old ones which are removed from the blood,” Dr Egg noted.
Old cells are less flexible and become stuck in the spleen and liver, where they are engulfed by white blood cells. Circadian disruption appears to inhibit this removal process, but the researchers are unsure why this is the case.
They do know that having large aggregates of old RBCs in the vessels increases the chance of a clot that could lead to a heart attack. This may explain why shift workers have a 30% higher risk of cardiovascular disease. In addition, the decreased functionality of the aged cells reduces the oxygen-carrying capacity of the blood.
However, the researchers also found that zebrafish were less affected by circadian disruption if they were simultaneously exposed to hypoxic conditions. This is because hypoxia stimulates the production of fresh RBCs.
The team noted that the cell signaling pathways that regulate circadian rhythms and the hypoxic response are intrinsically linked. This is based on the observation that genes activated by hypoxia, such as erythropoietin, normally show a daily rhythm of activity that becomes disturbed under hypoxic conditions.
“In zebrafish, hypoxia in combination with jetlag led to the production of fresh red blood cells, counteracting the harmful consequences of jetlag and reducing mortality by 10%,” Dr Egg noted.
“Blood donations in humans also stimulate the generation of new fresh erythrocytes. Therefore, blood donations on a regular basis might be a very simple measure to help decrease the cardiovascular risk in human shift workers.”
Dr Egg and her colleagues are currently investigating whether circadian disruption affects any other physiological processes, apart from the cardiovascular system.