Mitochondrial DNA Insertions into Nuclei of Brain Cells

 

It has recently been discovered that mitochondria have been inserting bits of mitochondrial DNA into the nuclei of brain cells at unusually high rates. During a study on over 1,200 older adults, it was found that the more mitochondrial insertions an individual had, the younger they died. One of the normal functions of mitochondria is to ship their DNA into the nucleus of the cell to integrate it with the nuclear DNA in a process called numtogenesis. Numtogenesis has been commonly observed in reproductive cells and cancer cells but has never before been observed in brain cells. These insertions were studied on blood cells and brain tissue from the cerebellum and the dorsolateral prefrontal cortex, or DLPFC. What they found is that cells from the DLPFC had an average of 15 times as many insertions as the blood cells and 5 times as many insertions as the cerebellar cells. It was also discovered that mitochondrial insertions increased under certain stressors such as drug treatments or genetic mutations.

 

In my opinion, this is something that definitely needs more attention. I believe this is something necessary to further study. This study seems to suggest that numtogenesis is somehow linked to life span. Since the DLPFC has been known to be affected by many age related and neurodegenerative conditions, the higher rate in mitochondrial insertions in the DLPFC could provide a potential explanation or be linked as a factor. With this knowledge we could potentially develop improved treatments for these conditions.

Are you as old as you think you are?

According to a study done Kings College in London, someones actual age might not exactly link up to their biological age. "By reading a "signature" based on 150 of a person's genes, researchers can determine the individual's biological age, which may be different from his or her chronological age, according to a new study" (Miller).  This may be good news in research towards prevention for diaereses since knowing someones biological age is better for determining someones actual health. Studies showed someones biological age is closely linked to the risk of getting certain age related diseases such as dementia. While two people could been the exact same age, they could still have completely different biological ages and have completely different risks to watch out for. Now a days insurance companies are even finding peoples chronological ages to help set insurance premiums to determine their risk for certain diseases with knowledge found from studies like this one.  Researchers found 150 genes that can be calculated to find a persons healthy age gene score. To test the study they tried it on a group of 70 year old's. The findings were that people with a higher score did show linkage between a persons good health. In patients with Alzheimer's disease it was found that their scores were very low.  "This provides strong evidence that dementia in humans could be called a type of 'accelerated aging' or 'failure to activate the healthy aging program,'" Timmons said.

This is an amazing and interesting article because it gives insight to why people of the same age might have drastically different health related diseases. Hopefully with further studies of the 150 genes used to understand chronological age can give us greater insight on the causes of Alzheimer's diseases and lead us to discover new ways to possibly treat or prevent the disease. This could also help with finding out reasons why people age biologically more then others. 

Link to article: http://www.livescience.com/52105-biological-age-cognitive-health-genes.html

To find out more about Alzheimer's early signs go to: http://www.livescience.com/35611-alzheimers-disease-brain-shrink-early-signs.html 

Obesity Linked to the Biological Age of Newborns

A recent study shows that a mothers' obesity may affect the biological age of her newborn child. This study, conducted at Hasselt University in Belgium, associates a shorter telomere length (located in the cells of the newborn) with the obesity of their mother. Researchers that conducted this study used a sample of 743 mothers, ranging from the age of 17 to 44, The researchers were able to use samples of umbilical cord blood obtained from each newborn, directly after their delivery.

Biological age is essentially the number of times a cell will be able to divide in its lifetime, which is typically determined by the length of the telomeres in the cells of our bodies. Telomeres are vital to have in a person's genome, given that they protect chromosomes from degrading; they are the structures at the ends of chromosomes. Given this benefit, cells then have a more likely chance of dividing throughout their lifetime depending on the length of the telomere that ends the chromosome in which it is attempting to divide.

After observing all of the data gathered throughout this study, it remained prevalent that newborns whose mothers were not considered obese had longer telomeres versus newborns who had mothers that were indeed considered obese. In fact, only a single point increase in a mother's body mass index, or ones' weight-to-height ratio, was linked with newborns whose telomeres were shortened by about fifty base pairs considered to the average newborn's telomere length. Although it is normal for telomeres to shorten as people age, the rate at which telomeres shorten does not remain consistent between individuals. The fifty base pair shortage in these newborns is actually equal to the amount of base pairs an adult would lose on average in only a bit over a year.

According to previously done studies, the length of telomeres in adults may be associated with some age-related diseases such as cardiovascular disease, type 2 diabetes and increased mortality; however, studies on the impacts of telomere length in newborns and children still remains limited. This study also does not take into account the body mass index, or the obesity of the paternal figure, which also may play a part in the length of the telomeres. Several factors have been ruled out to lead to the length of the telomeres; however, this is being further looked into.

I am very curious to see how this study will continue, and what further findings these researchers may have. I think it would be extremely important to learn about the influence of telomere length in newborns and children, given the associated health risks in adults. I also am very curious to see what role the paternal BMI, or possible other factors, will play in the deciding of the length of the newborn's telomeres.