Medical Bulletin 20/ February/ 2025
Here are the top medical news for the day:
CRISPR Technology Shows Promise in Removing Extra Chromosomes in Down Syndrome
Gene editing techniques may eventually allow trisomy to be treated at the cellular level, according to an in vitro proof-of-concept study, published in the PNA Nexus Journal.
Down syndrome is caused by the presence of a third copy of the 21st chromosome. The condition occurs in approximately 1 in 700 live births and is relatively easy to diagnose at early stages of development. However, there are no treatments.
Ryotaro Hashizume and colleagues use the CRISPR-Cas9 gene editing system to cleave the third chromosome in previously generated trisomy 21 cell lines derived from both pluripotent cells and skin fibroblasts. The technique can identify which chromosome has been duplicated, which is necessary to ensure the cell does not end up with two identical copies after removal, but instead has one from each parent.
The authors were able to remove duplicate chromosomes from both induced pluripotent stem cells and fibroblasts. Suppressing chromosomal DNA repair ability increased the rate of duplicate chromosome elimination.
Therefore, the researchers showed that the chromosomal rescue reversibly restores both gene expression and cellular phenotypes. The approach is not yet ready for in vivo application, however, in part because the current technique can also change the retained chromosomes. According to the authors, similar approaches could eventually be used in neurons and glial cells and form the basis of novel medical interventions for people with Down syndrome.
Ref:
Ryotaro Hashizume, Sachiko Wakita, Hirofumi Sawada, Shin-ichiro Takebayashi, Yasuji Kitabatake, Yoshitaka Miyagawa, Yoshifumi S Hirokawa, Hiroshi Imai, Hiroki Kurahashi, Trisomic rescue via allele-specific multiple chromosome cleavage using CRISPR-Cas9 in trisomy 21 cells, PNAS Nexus, Volume 4, Issue 2, February 2025, pgaf022, https://doi.org/10.1093/pnasnexus/pgaf022
Study Finds Blocking Mobile Internet on Smartphones Boosts Attention, Mental Health, and Well-Being
Smartphones enable people to access the online world from anywhere at any time. Despite the benefits of this technology, there is growing concern that smartphone use could adversely impact cognitive functioning and mental health.
According to a recent research published in the PNA Nexus Journal, shows a link between smartphone usage and attention, mental health and well- being. Correlational and anecdotal evidence suggests that these concerns may be well-founded, but causal evidence remains scarce.
The researchers conducted a month-long randomized controlled trial to investigate how removing constant access to the internet through smartphones might impact psychological functioning. They used a mobile phone application to block all mobile internet access from participants’ smartphones for 2 weeks and objectively track compliance. This intervention specifically targeted the feature that makes smartphones “smart” (mobile internet) while allowing participants to maintain mobile connection (through texts and calls) and nonmobile access to the internet (e.g. through desktop computers).
The intervention improved mental health, subjective well-being, and objectively measured ability to sustain attention; 91% of participants improved on at least one of these outcomes. Mediation analyses suggest that these improvements can be partially explained by the intervention's impact on how people spent their time; when people did not have access to mobile internet, they spent more time socializing in person, exercising, and being in nature. These results provide causal evidence that blocking mobile internet can improve important psychological outcomes, and suggest that maintaining the status quo of constant connection to the internet may be detrimental to time use, cognitive functioning, and well-being.
Ref: Noah Castelo, Kostadin Kushlev, Adrian F Ward, Michael Esterman, Peter B Reiner, Blocking mobile internet on smartphones improves sustained attention, mental health, and subjective well-being, PNAS Nexus, Volume 4, Issue 2, February 2025, pgaf017, https://doi.org/10.1093/pnasnexus/pgaf017
New Study Reveals Genetic Factors Influencing Success in Quitting Smoking
The effectiveness of a common drug to quit smoking could be down to people’s genes, according to a study from the University of Leicester (United Kingdom). Varenicline is widely recognised as the most effective medication for helping people stop smoking, but unfortunately it does not work for everyone.
Researchers from Leicester have uncovered important insights into how people’s DNA affects their response to the drug, which will soon be available to smokers. Varenicline works by targeting specific receptors in the brain to block the rewarding effects of smoking and reduce cravings.
An international team of researchers developed a method to use electronic health records to identify people who successfully stopped smoking with varenicline and those who did not.
The study, published in Nicotine and Tobacco Research, uncovered individual genetic variants (small differences in the DNA sequence) linked to stopping smoking using varenicline. The identified genetic variants highlight the involvement of genes in regulating gene activity and in the function of hair-like extensions of cells, called cilia.
Dr Kayesha Coley, the study’s lead researcher, said: “Our study is the first to scan the entire genome to look for genes linked to successfully stopping smoking using varenicline. The genes give us some useful insights into the diverse biological processes at play, but the next step is to confirm our findings with even larger studies.
The research team emphasised the importance of continued studies in this area to further investigate how genetics influences the success of varenicline and further enhance biological understanding.
Ref: Kayesha Coley, Qingning Wang, Richard Packer, Catherine John, Erik Abner, Kadri Reis, Estonian Biobank Research Team, Khaled F Bedair, Sundararajan Srinivasan, Sara Paciga, Craig Hyde, Robert C Free, Nicola F Reeve, David J Shepherd, Tõnu Esko, Colin Palmer, Ewan Pearson, Anders Malarstig, Martin D Tobin, Chiara Batini, Genome-Wide Association Study of Varenicline-Aided Smoking Cessation, Nicotine & Tobacco Research, 2025;, ntaf009, https://doi.org/10.1093/ntr/ntaf009
New Tool Links Immune Cell Disruption in Blood to Cancer Outcomes
The immune systems of cancer patients are highly disrupted, with those who have a higher number of immune cells in their blood having a better survival rate, finds a new study, published in Nature Genetics.
The tool is called Immune Lymphocyte Estimation from Nucleotide Sequencing (ImmuneLENS). It enables researchers to calculate the proportion of T cells and B cells (types of immune cell) from whole genome sequencing (WGS) data for the first time.
Whole genome sequencing (WGS) uses a blood sample to create a complete record of an individual’s DNA, the genetic instructions that determine who they are. By understanding these instructions, scientists can find out important information such as how many immune cells a person has, if there are any changes in their genes, and how their body is combating disease. This can be helpful for studying genetic illnesses such as cancer.
They found that cancer patients had a lower proportion of T cells circulating in the blood compared to healthy individuals. Further, T cell proportion was found to be a strong predictor of cancer outcomes, with higher proportions associated with 47% fewer deaths over a five-year period after surgery.
Professor Nicholas McGranahan, senior author of the study from UCL Cancer Institute, said: “Most immune system analysis until now has focused on the tumour itself, so the results we’re seeing using this new technique – which examines the number of immune cells in a person’s blood – are of considerable interest. What’s going on with immune cells in the blood seems to have a huge impact on cancer survival and may be able to predict how long a cancer patient will survive better than the number of T cells in the tumour alone.
Ref: Bentham, R., Jones, T.P., Black, J.R.M. et al. ImmuneLENS characterizes systemic immune dysregulation in aging and cancer. Nat Genet (2025). https://doi.org/10.1038/s41588-025-02086-5
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