The developing heart in an embryo can be damaged by the cellular stress triggered from oxygen deficiency, thereby leading to development of childhood heart disease, a study has revealed for the first time.
Childhood heart disease is the most common form of birth defect and affects one in 100 babies globally, showed the study. "The study discovered that reduced oxygen triggered a stress response in the embryonic cells. The cells try to relieve the stress by stopping protein production. As proteins aren't available to make the heart at a critical time, it doesn't develop properly," lead researcher Professor Sally Dunwoodie at Victor Chang Cardiac Research Institute said.
According to the work published in the journal Development, the oxygen deficiency in an embryo can be caused by multiple factors such as prescription medications, high blood pressure, high altitude, or even a tangled umbilical cord. Apart from low oxygen, factors like a viral infection, increased temperature, high blood glucose, poor nutrition and pollution can also trigger cellular stress.
The findings showed that cellular stress -- wide range of molecular changes that cells undergo in response to environmental stressors like extreme temperatures, exposure to toxins and mechanical damage -- are the key reasons for the multiple types of defects in heart, vertebrae and kidney, among others, during birth. "Surprisingly, this cellular stress response has been used for hundreds of millions of years and it is only now that we have discovered that it can cause organs, such as the heart, not to form properly" added Dunwoodie.
For the study, the team used a mouse model and reduced the oxygen levels inside a chamber from the normal level of 21 per cent to as low as 5.5 per cent, for eight hours. They found for the first time that reduced oxygen levels damaged the developing heart. The types of heart defects were the same as those most commonly found in humans, the researchers noted.