1. After cancer cells release a substance, immune cells can only put down their weapons
Cancer cells in the human body grow and divide quickly, and can spread through some changes. But how new cancer cells avoid the immune system has long troubled scientists.
Recently, in a new study published in " Science ", scientists at Harvard Medical School discovered that cancer cells can avoid the immune system in a way so that cancer cells can grow.
They noticed the presence of mutations in the gene IDH expressing isocitrate dehydrogenase (isocitrate dehydrogenase) in 3.5% of cancer cells. In low-grade gliomas and secondary gliomas, this gene mutation is present in nearly 80% of cancer cells, which secrete D-2-hydroxyglutaric acid (D-2HG), which is usually at a relatively low level in the human body.
Previous studies have shown that D-2HG can allow tumors to enter a radical and rapid division state. The new study found through mouse experiments that after D-2HG enters T cells, , it will inhibit a key enzyme in the cell - lactate dehydrogenase . Once inhibited, T cells will not be able to continue to produce cytokine and maintain toxicity, which are the key to T cells maintaining tumor killing ability.
However, this process is reversible. The researchers also observed that an increase in D-2HG in the tumor microenvironment also reduced the permeability of T cells to the tumor. This research may promote the development of some therapies that use the immune system to kill tumors.
2. Chinese scholars have discovered a new mechanism for extending lifespan of metformin
metformin is a first-line drug widely used in the treatment of html type 12 diabetes . It has been shown in animal models to extend lifespan and delay the onset of age-related diseases. However, in practical applications, there is still a lot of room for exploration to the association between metformin and life expectancy.
Recently, researchers from 公司有公司有公司有公司有公司有公司有公司有公司有公司有公司有公司有公司有公司有公司有公司有公司有公司有公司有公司有公司有公司有公司有公司有公司有公司有公司有公司有公司有公司有公司有公司有公司有公司有公司有公司有公司有公司有公司有公司有公司有公司有公司有公司有公司有公司有公司有公司有公司有公司有公司有公司有公司有公司有公司有公�
SAM is the only methyl donor modified histone, and its fluctuations may be related to changes in histone methylation. To determine whether metformin-induced SAM restriction affects histone trimethylation, the researchers tested four histone trimethylation markers H3K4me3, H3K9me3, H3K27me3, and H3K36me3 through western blot experiments in adults and larvae. Metformin was found to significantly reduce the levels of H3K4me3 in adults but not larvae.
However, after metformin treatment, there was no change in the levels of H3K9me3, H3K27me3 and H3K36me3 in adults or larvae. In summary, these results indicate that metformin-induced SAM restriction affects the H3K4me3 modifier of nematode .
Simply put, This study links metformin, SAM restriction, histone methylation and healthy lifespan, and elucidates that metformin regulates the model role of healthy lifespan prolongation will promote its therapeutic application in the treatment of human aging and age-related diseases.
3. Compared with fat, the waist is even more fatal. For every unit added to waist and hips, the risk of death doubles
says that fatness is the "source of all diseases". In China, overweight and obese people have exceeded 300 million, and central obesity (which we commonly call " general belly ") is the most common type of obesity.
study shows that central obesity may be more correlated with mortality risk than overall obesity. Recently, a study from the University of Cork in Ireland further confirmed this. The study showed that for predicting the risk of death, the waist-to-hip ratio is better than BMI, and the lower the waist-to-hip ratio of , the lower the risk of death. The waist-to-hip ratio is a better measure of healthy weight, and it predicts the risk of premature death more accurately than BMI.
BMI index, that is, the body mass index, is currently a common standard for measuring the degree of weight and whether the human body is healthy.BMI = Weight divided by height square, BMI between 18.5-25 is considered to be within a healthy weight range, greater than 25 is overweight, and greater than 30 is obese.
Because BMI only calculates individual height and weight without taking into account fat distribution, the researchers said BMI cannot reliably predict the risk of disease or death.
In this study, the researchers analyzed whether waist-to-hip ratio (WHR) or fat mass index (FMI) can more reliably predict mortality rates for different fat distributions.
First, researchers determined whether obesity actually leads to an increase in mortality, and an analysis of known genes in UK Biobank data shows that obesity actually leads to an increased risk of death, not just related to it.
Then, the researchers applied genetic determination of genes associated with BMI, WHR and FMI to 25,297 Caucasian participants with an average age of 61.6 years and 59.3% were male. The health of all participants was followed by the UK Biobank study until they died. In addition, 25,297 matching control groups were included.
study found that the relationship between waist-to-hip ratio and all-cause death increased linearly, and people with the lowest waist-to-hip ratio had the lowest risk of early death, and then steadily increased with the increase of waist-to-hip ratio.
In contrast, BMI and FMI were in a J-shaped relationship with all-cause mortality, which means that patients with extremely high or very low BMI were more mortality compared with moderate BMI or FMI.
study showed that compared with BMI or FMI, the correlation between waist-to-hip ratio and all-cause mortality was consistent with different fat distributions. For each unit increase in waist-to-hip ratio, the risk of premature death is almost twice as high as per unit increase in BMI or FMI.
In addition, compared with women, male waist-to-hip ratio was stronger in males than females.
researchers said the main limitation of BMI is because it does not take into account differences in fat distribution. However, waist-to-hip ratios can better reflect the levels of abdominal fat, including visceral fat , which increases the risk of a range of diseases, including type 2 diabetes and heart disease.
In summary, the study concluded that waist-to-hip ratio should replace BMI as a simple indicator of healthy weight. Researchers recommend that waist-to-hip ratio should be given priority in clinical practice rather than general BMI goals. More accurate measurements of healthy body shape can have a significant impact on poor health and death caused by type 2 diabetes, heart disease, certain cancers, etc.
(Information comprehensive source: Science Network, Biological Valley)
