13 days, make skin cells 30 years younger and restore their ability to produce collagen | Global scientific news

? Regenerative medicine?

13 days, make the skin 30 years younger.

In 2007, Shinya Yamanaka first used cell reprogramming technology to transform normal cells with specific functions into pluripotent stem cells (iPSC), and won the Nobel Prize for this, but normal cells lose their specific function in the process. Recently, a study published in eLife builds on this work by stopping partial reprogramming during stem cell redifferentiation, preserving the specific function of skin cells and "rejuvenating" skin cells.

The researchers used middle-aged epithelial fibroblasts, which secrete collagen, which can maintain skin elasticity and repair skin damage. After 13 days of treatment, the researchers measured the degree of histone methylation and DNA methylation, which showed that the biological age of fibroblasts was about 30 years younger. At the same time, the migration ability of these fibroblasts and the production of collagen were greatly increased. This is more effective than previous experiments on inducing pluripotent stem cells. The researchers hope that the development of cell reprogramming technology will provide new solutions for the treatment of age-related diseases such as Alzheimer's disease in the future.

? COVID-19 epidemic?

The reasons for the loss of sense of smell in COVID-19 infected patients

Many people infected with novel coronavirus will have the problem of loss of sense of smell or disappearance, but the mechanism behind this phenomenon is not clear. Recently, a study published in the Journal of Neurology of the American Medical Association shows that loss of sense of smell is likely to be the effect of inflammation rather than a direct effect of viral infection.

The researchers examined the olfactory bulb regions of 23 donors who died of novel coronavirus infection and 14 donors who died of other causes and did not infect novel coronavirus at the time of death. The olfactory bulb is the olfactory center of the brain and can process olfactory information from different sensory neurons. The researchers found that donors who were infected with novel coronavirus and had a decreased sense of smell had more severe vascular damage in the olfactory bulb region and a significant decrease in the number of axons, regardless of age. To the researchers' surprise, novel coronavirus particles were not detected in the olfactory bulb area of most COVID-19 infected people. The researchers believe that novel coronavirus infected the olfactory epithelium, causing nerve inflammation, reducing the number of axons that can send signals to the brain and causing the olfactory bulb to malfunction.

? Astronomy?

The temperature fluctuation of Neptune is greater than expected.

Neptune has the same seasonal changes as Earth, but each season lasts about 40 Earth years because of its longer orbit around the sun. Recently, a multinational cooperative study comprehensively analyzed the thermal infrared spectrum data of Neptune from several observation stations such as very large telescopes in the past 20 years, and mapped the changing trend of its atmospheric temperature. The study is published in the Journal of Planetary Science.

Since the observation began in the early summer of Neptune, scientists expect temperatures to rise steadily. However, the researchers found that the average stratospheric temperature of Neptune dropped by about 8 ℃ from 2003 to 2018. But from 2018 to 2020, Neptune's stratosphere at the South Pole rose sharply by 11 ℃, reversing the previous global cooling trend. The cause of such temperature fluctuations is not clear, but it is speculated that it may be related to solar activity. The researchers revealed a possible correlation between solar activity, Neptune's stratospheric temperature and the number of bright clouds visible on Neptune, but further observations of Neptune's temperature and cloud patterns are needed to further assess whether the correlation is temporary.

? Medicine?

Ciloxibin increases brain connectivity in the treatment of depression

Patients with depression often show "negative cognitive bias", which is characterized by pessimism, poor cognitive flexibility and rigid way of thinking, as well as long-term negative attitude towards "self" and the future. At present, clinical trials have reported that ciloxibin (also known as psilocybin, a natural neurotoxin with neurohallucinogenic effect) can improve depressive symptoms and treat refractory depression that can not be improved by multiple courses of antidepressants. A new study published in Nature Medicine reveals why ciloxibin works in patients with refractory depression.

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The researchers collected and analyzed two clinical trials to verify the efficacy of ciloxibin. In the first trial, there were 16 patients with refractory depression (median age 42.75 years; 25% female). The second trial analyzed brain imaging data from 43 patients with major depressive disorder, of whom 22 (median age 44.5 years; 36% female) were treated with ciloxibin. the other 21 (median age 40.9 years; 29% were women) used the traditional antidepressant escitalopram and low doses of ciloxibin. The study found that, in contrast, ciloxibin has a rapid, considerable and lasting antidepressant effect, which is significantly better than that of escitalopram. After taking ciloxibin, the high-order brain functional network rich in 5-HT2A receptors becomes more flexible and more closely related. Studies have shown that ciloxibin has a new mechanism different from traditional antidepressants: increasing the connection and integration of brain functional networks.

? Quantum communication?

Tsinghua University realizes 100 km Quantum Direct Communication for the first time

Recently, the Physics Department of Tsinghua University announced that the cooperation team of the Physics Department and the Electronics Department have implemented a new quantum direct communication system with a communication distance of 100 kilometers for the first time, which is currently the longest quantum direct communication distance in the world. it is helpful to realize intercity quantum direct communication without relay. The related results are published in Light-Science&Applications.

The team designed and implemented a new quantum direct communication system with phase quantum state and timestamp quantum state mixed coding. The timestamp quantum state can be used for sampling detection and greatly reduce the influence of noise. The new system has high stability and low intrinsic bit error rate, which effectively improves the secure communication capacity, distance and rate. The quantum direct communication distance of the system reaches 100 km for the first time, which can realize point-to-point quantum direct communication between cities without relay, and can support some applications of wide area quantum network based on secure classical relay.

? Healthy?

Effect of smoking on lung cell mutation

Smoking is the main cause of lung cancer, which is generally believed to be caused by DNA mutations in lung cells caused by smoking, but it has not been confirmed before. In a new study published in Nature Genetics, the researchers sequenced the lung epithelial cells of 33 participants with different smoking histories using a new single-cell whole-genome sequencing technique and found that the frequency of DNA mutations increased significantly in smokers compared with non-smokers, consistent with previous assumptions. The researchers believe that this may be one of the reasons why non-smokers rarely get lung cancer, while 10% to 20% of lifelong smokers get lung cancer.

The researchers compared the number of DNA mutations in lung epithelial cells with tobacco exposure (in "package years", that is, daily smoking (packets) × smoking time (years)), and produced another interesting finding: when tobacco exposure was less than 23 packets, the number of DNA mutations increased linearly with tobacco exposure, but t