Neurogenesis is the process wherein neurons are born or generated from neutral stem cells and progenitor stem cells. It is responsible for filling the brain with neurons, making the brain function properly. This progression is most active during prenatal development.
It was believed that neurogenesis ceases once a person reaches adulthood. Recent studies, on the other hand, have shown that neurogenesis is still active in some parts of mammal brains, specifically, the hippocampus and subventricular zone, well into adulthood and running is a great and inexpensive way to increase the rate of neurogenesis in humans.
Recent study described here finds running to be a potential treatment for Charge syndrome patients as well as improve other mental capabilities
CHARGE Syndrome’s Effects on Mental Development
CHARGE Syndrome, a very rare disease that affects one person in every 10,000 births around the world, is considered an enemy of neurogenesis. Individuals with CHARGE Syndrome suffer from vision and hearing loss, as well as balance problems, which can cause and generally affect a child’s development both physically and mentally, as well as his capacity to communicate, rendering neurogenesis nearly useless.
CHARGE stands for coloboma, heart defects, atresia choanae, retardation, genital/urinary tract defects and ear abnormalities.
It is often misconstrued that children afflicted with CHARGE Syndrome are mentally retarded. This is not wholly true. While CHARGE and mutations of the CHD7 gene, per se, may show signs of delayed mental and intellectual development, children suffering from CHARGE are not necessarily mentally-impaired. Due to visual and hearing loss caused by this medical anomaly, affected patients may indeed have trouble communicating, or at least in terms of interpreting what they have heard or seen. However, not all CHARGE-afflicted patients have learning disabilities.
Behavior and Communication
CHARGE patients, as we know, develop later – much later, in some cases – compared to children without birth defects. In this aspect, communication is very important in helping a CHARGE patient to overcome his defects. Since formal speech or communication may be underdeveloped, it is imperative that a parent or educator need to understand what a child with CHARGE Syndrome is trying to tell us.
Let us bear in mind that children with CHARGE may have behavioral manifestations that we might find offensive or abnormal, compared to children who do not suffer this genetic disorder. One example is the lack of correct or proper eye contact. This is prevalent among individuals with central visual impairment and may or may not be directly caused by hearing loss. A normal person will look you straight in the eye when talking, however, a CHARGE patient may slightly avert his face, making it looks as though he is avoiding eye contact, when it truth, that person cannot see properly if he is facing you directly. With children, they may act as though they are not paying attention since any form of communication that is not within the periphery of their (defective) vision are lost to them.
Another seemingly insurmountable effect of CHARGE Syndrome is the patient’s high threshold for pain, which borders on indifference. Since children suffering from CHARGE do not feel physical or emotional pain like a normal person, they might inflict pain to others and still not be affected by the person’s reaction. This is mainly due to the fact the CHARGE patients do not or have not experienced due to the nature of their abnormality.
Social behaviors, such as immaturity, are also major concern for parents with CHARGE-afflicted children. These children find it difficult to maintain proper decorum in public and maintaining harmonious relationships and friendships are lost to them or difficult to understand the internalize.
What is CHD7 and its Effect to a Child’s Development?
These birth anomalies are caused by the random mutation of CHD7, or Chromodomain-helicase-DNA-binding protein 7, a gene found in the long arm of chromosome 8. This gene affects the activation and deactivation of other important genes.
There are no specific findings regarding the mutations of CHD7, nor is there any known specific stimulus or factors that cause such mutation, however, it is generalized to cause several birth defects. Mutations of CHD7 are also found to be the causes of several forms of cancer such as colon or lung cancers, and brain tumors to name a few.
The CHD7 mutations are found in about 60% to 65% of individuals with cases of CHARGE Syndrome. This gene has at least 150 mutations found in its entirety. These mutations cause the production of dysfunctional and abnormally short CHD7 proteins, which, in turn manifest themselves as congenital defects.
It is also found in studies that CHARGE Syndrome and its symptoms are caused by the mutations in the CHD7 gene in as early as during embryonic development.
CHD7’s Effect on Neurogenesis
Increased physical activities, such as running, were found to help increase the number of newborn neurons in the hippocampus, as a result of experiments on lab mice.
Dr. Haikun Liu at the Cancer Research Center (Deutsches Krebsforschungszentrum, DKFZ) in Germany had conducted an experiment on patients with mental and developmental disabilities, specifically those afflicted with CHARGE Syndrome, targeting the effect of voluntary exercise on persons with central nervous system defects.
Dr. Liu’s team experimented on genetically altered mice. They cut off the regular development of the CHD7 gene in neural stem cells throughout different stages of neurodevelopment. Their goal is to find out how cells can function without the presence of CHD7.
The scientists have found that the absence of CHD7 kept cells from developing into matured neurons, thus slowing down neurogenesis and mental development. This mutation prevented neurons from forming into neural networks, the very essence and function of the central nervous system, which in turn, affects mental maturation.
Running as a Stimulant for Neurogenesis
Dr. Liu’s research had led his team to find out that voluntary physical activities, such as running, helped the experimental mice to recover lost CHD7. The mice that constantly run on running wheels completely recovered from CHD7 deficiency. This proved that neurogenesis is greatly enhanced by running, which was proven on both animals and humans.
Due to this experimentation, scientists now believe that CHARGE Syndrome and its effects to the human nervous system can be treated and potentially improved.
According to Dr. Liu, they are excited to further search for solutions to bypass CHD7 mutations by means of running. They have found the cause and the effect, and they are currently working on the means to find out what is the underlying mechanism in the human brain that makes this possible.