In 2019, scientists continued to test and push the boundaries in terms of what is possible in the diagnosis and treatment of some of the world's most difficult diseases. Here are a few more of the positive health news stories which were published in 2019.
People can continue making new brain cells until at least they are 97 years old
Scientists have been tracking whether the brain is still able to make new brain cells throughout all of its life and it would appear the answer is yes. The study was published in Nature Medicine, by scientists from the University of Madrid, who examined brains donated by volunteers after death The ages of the people who had donated the brains varied between 43 and 97 years of age. The researchers were looking in particular at the hippocampus, which stores memories and emotion, examining it for signs of new brain cell growth or neurogenesis. They found that they were able to find signs of immature or new neutrons in the hippocampus in brains of people of all ages. Although there was a slight decrease in number of immature neurons, the older the person got, however they were able to identify signs of immature neurons in the brain of a 97 year old.
Where a patient had been diagnosed with Alzheimer’s disease, the scientists found a difference. The number of new neurons forming fell by about one third for these patients, even when people were only just diagnosed with the disease. It was too early for the build-up of amyloid plaque, normally associated with the disease and probably too early for symptoms to be showing.
The scientists noted that studying why there is a decrease in the formation of new herons could help to develop new treatments both for people who have been diagnosed with Alzheimer’s disease and those who have normal ageing. They felt that there was a need for larger studies, which could examine the brains of people while they are still alive, to try and identify a test which could pinpoint those who could be most at risk of from the disease.
Llorens-Martin, M., et al., Adult hippocampal neurogenesis is abundant in neurologically healthy subjects and drops sharply in patients with Alzheimer’s disease, Nature Medicine 25, 554-560 (2019)
Gene silencing - a new form of treatment was approved for use by the NHS in 2019. The drugs can be used to help reverse amyloidosis, a disease which can cause organ and nerve damage. It is hereditary, causing s build up of proteins in the organs of the body. It can affect sexual function, seating and eating. People diagnosed with the disease can end up in a wheel chair, suffering from a weakened heart and chronic pain as well as using the use of their legs. The disease appears in different forms and is often fatal between 3-15 years of symptoms first being noticed.
Gene silencing attacks the messages that are carried between DNA itself and a cell’s protein-making cells. Scientists found in a 2018 study that this drug could stop the disease from progressing or even reverse it.
Amyloidosis was previously considered untreatable. The drug can also work within other genetic diseases such as porphyria, and Huntingdon’s disease has also been shown to be helped by gene silencing.
Adams, D., et al., Patisiran, an RNAi Therapeutic, for Hereditary Transtheyretin Amyloidosis, The New England Journal of Medicine, July 2018
Mealworms can safely consume toxic plastic
A team of scientists have found that mealworms are able to safely consume toxic plastic and are then safe, themselves to be food. Their findings were published in Environmental Science & Technology and the supporting information is available to read online. Previous studies have shown mealworms’ ability to eat a variety of plastic forms, but this study examined their ability to eat potentially toxic additives in styrofoam, showing no ill-effects and with no toxic products remaining, so that the mealworms that ate the styrofoam, could, themselves be used as food.
The styrofoam used in the study contained a commonly used flame retardant, called hexabromocyclododecane or HBCD. It is used to improve the plastic’s ability to be used in manufacturing or to reduce its flammability. The EU are looking to ban the chemical because of the significant health and environmental impacts it can have.
Micro-organisms in the mealworm’s stomach can biodegrade the plastic that they have eaten, however about half of toxic plastic eaten was excreted as partially degraded, small fragments. The other half was excreted as carbon dioxide. After 24 hours, 90% of the HBCD had been excreted and after 48 hours, it had all gone. The worms that had eaten the styrofoam were as healthy as other mealworms and the shrimp that feasted on them were also healthy.
The study had some limitations: the excreted HBCD was still hazardous and that not all common additives in plastic may be able to be disposed of in this way. The scientists warned that reduced reliance on single-use plastic products and more work on biodegradable plastic replacements remained the best way forward to combat the plastic crisis.
Brandon, A.M., et al., Fate of Hexabromocyclododecane (HBCD), A Common Flame Retardant, In Polystyrene-Degrading Mealworms: Elevated HBCD Levels in Egested Polymer but No Bioaccumulation, Environ.Sci.Tech., 2019