neurodegenerative diseases

Physical inactivity is a risk factor for the onset of Alzheimer's disease. An international team has studied nearly 300 people with preclinical Alzheimer's—without symptoms but with an accumulation of tau and beta-amyloid proteins in the brain—for 14 years to find out whether physical exercise can also influence its progression. The results indicate that even very moderate activity—walking between 3,000 and 5,000 steps per day—was associated with slower deterioration, while the benefits—which appear to be related to lower tau protein deposits—were greater and tended to stabilise with activity involving between 5,000 and 7,500 steps. The results are published in the journal Nature Medicine.

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterised by progressive loss of motor neurons. An international team has discovered evidence that ALS may have an autoimmune component, meaning that the immune system mistakenly attacks healthy cells, a hypothesis that had been considered by the scientific community. The study shows that inflammatory immune cells—called CD4+ T cells—attack certain proteins that are part of the nervous system in people with ALS. ‘These findings highlight the potential of therapeutic strategies aimed at improving regulatory T cells,’ the authors note in the research, published in Nature.

An international team with Spanish participation has analyzed data from more than 500,000 people and found a link between digestive disorders such as colitis, gastritis, esophagitis, or functional bowel disorders and an increased risk of developing Alzheimer's and Parkinson's diseases. According to the researchers, who published their findings in the journal Science Advances, “this effort sheds light on the interaction between factors involved in the gut-brain axis and opens avenues for targeted treatment and early diagnosis.”

Researchers at Harvard Medical School have published new findings in Nature on the role of reduced lithium levels in Alzheimer's disease, based on experiments with mice and analysis of brain tissue and blood samples from humans. The team claims to have achieved improvements in memory in mouse models with lithium orotate. They caution that they have not proven that lithium is safe or effective in protecting against neurodegeneration in patients, and that their findings must be confirmed in humans through clinical trials.

Researchers in the United States have used stem cells created from patients with a very rare type of ALS, more prevalent in Brazil, to target a key gene in the stress response and reverse the damage suffered by motor neurons in the laboratory. They believe it is "a promising proof-of-concept for future therapeutic strategies" and "could help lay the foundation for genetically informed clinical trials".

A US study analysing data from nearly 700,000 people concluded that those with a history of herpes simplex virus (HSV-1) infections were at greater risk of developing Alzheimer's disease. The study, published in BMJ Open, also showed that patients with this virus who used anti-herpes treatments were less likely to develop the disease.

Consumption of ultra-processed food is associated with an increased likelihood of having prodromal signs of Parkinson's disease - symptoms that precede the disease - says a study published in Neurology. The analysis is based on data from more than 42,000 healthcare professionals in the US, followed for up to 26 years.

A phase III clinical trial involving nearly 34,000 people shows that lowering high blood pressure reduces the risk of dementia and cognitive decline. Participants were aged 40 or older, lived in rural areas of China, and had untreated hypertension. The study results are published in Nature Medicine.

Two independent clinical trials demonstrate the safety of stem cell therapies for Parkinson's disease. The papers, published in Nature, investigate the use of cells derived from human induced pluripotent stem cells and human embryonic stem cells, respectively. Parkinson's disease is characterised by the progressive loss of dopamine-producing neurons. Cell therapy, which replenishes dopamine-producing neurons in the brain, could provide a treatment with fewer adverse effects than current treatments. However, further research is needed to test the efficacy and benefits of these new therapies.

According to a meta-analysis published in Nature Human Behaviour, the widespread use of digital technology may be associated with lower rates of cognitive decline in people over the age of 50. The results of the study — which analysed 57 studies involving more than 400,000 people with an average age of 69 — seem to contradict the hypothesis that the daily use of technology weakens cognitive ability.