Rosario Sánchez Pernaute

Various studies have shown that smokers have a lower risk of developing Parkinson’s disease, but the causes remain unknown. A study has analysed the role played by carbon monoxide — a toxic gas produced by the combustion of tobacco — in this association. To this end, the team conducted a twelve-year follow-up study of more than half a million adults in China. The results show that regular smoking was associated with an increased risk of lung cancer, ischaemic heart disease, stroke and all-cause mortality, but with a lower risk of Parkinson’s disease. Most strikingly, amongst people who had never smoked, higher levels of exhaled carbon monoxide—which the authors measured—were associated with a lower risk of Parkinson’s disease. According to the study, published in JAMA Neurology, these findings demonstrate a possible protective role of carbon monoxide in the disease, rather than smoking itself.

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.