Human Kidney Cells

UK researchers have developed a method to 'time jump' human skin cells by 30 years, turning back the ageing clock for cells without losing their specialised function. The team from the Babraham Institute at University of Cambridge has been able to partly restore the function of older cells, as well as rejuvenating the molecular measures of biological age. Though the findings, published in the journal eLife, are at an early stage of exploration, it could revolutionise regenerative medicine. The new method overcomes the problem of entirely erasing cell identity by halting reprogramming part of the way through the process. This allowed researchers to find the precise balance between reprogramming cells, making them biologically younger, while still being able to regain their specialised cell function. In 2007, Shinya Yamanaka was the first scientist to turn normal cells, which have a specific function, into stem cells which have the special ability to develop into any cell type. The full process of stem cell reprogramming takes around 50 days using four key molecules called the Yamanaka factors. The new method, called 'maturation phase transient reprogramming', exposes cells to Yamanaka factors for just 13 days. At this point, age-related changes are removed and the cells have temporarily lost their identity. The partly reprogrammed cells were given time to grow under normal conditions, to observe whether their specific skin cell function returned. Genome analysis showed that cells had regained markers characteristic of skin cells (fibroblasts), and this was confirmed by observing collagen production in the reprogrammed cells. "Our results represent a big step forward in our understanding of cell reprogramming. We have proved that cells can be rejuvenated without losing their function and that rejuvenation looks to restore some function to old cells," said Dr Diljeet Gill, a postdoc at the Institute. "The fact that we also saw a reverse of ageing indicators in genes associated with diseases is particularly promising for the future of this work," Gill added. To show that the cells had been rejuvenated, the researchers looked for changes in the hallmarks of ageing. Researchers looked at multiple measures of cellular age. The first is the epigenetic clock, where chemical tags present throughout the genome indicate age. The second is the transcriptome, all the gene readouts produced by the cell. By these two measures, the reprogrammed cells matched the profile of cells that were 30 years younger compared to reference data sets. Further, the team tested the partially rejuvenated cells by creating an artificial cut in a layer of cells in a dish. They found that their treated fibroblasts moved into the gap faster than older cells. This is a promising sign that one day this research could eventually be used to create cells that are better at healing wounds. Read More► Drinking Coffee Could Benefit Heart, Help You Live Longer: Study

London: An edible additive used in foods such as baked goods, ice cream and salad dressings has the potential to harm our gut microbiota, finds a study. Introduced into the modern diet nearly half a century ago, the food additive E415, also known as xanthan gum, is also widely used as a substitute for gluten in gluten-free foods. When it was first introduced, xanthan gum was thought to not affect us as it was not digested by the human body. However, the new study, published in the journal Nature Microbiology shows that the additive nevertheless affects the bacteria that live in our intestines. And these bacteria are important for our health and well-being. "So far xanthan gum is considered a keto-friendly product. This is because it is believed that xanthan is not digested by the body and therefore it doesn't count in the daily calorie or macronutrient intake," said researcher Sabina Leanti La Rosa from Norwegian University of Life Sciences (NMBU) in Norway. However, she explains, the new study shows that gut bacteria break down xanthan gum to its constituent monosaccharides, which are subsequently fermented to produce short-chain fatty acids that can be assimilated by the human body. Short-chain fatty acids are known to supply up to 10 per cent of calories to humans. This suggests xanthan gum, approved as safe to use in foodstuffs in large parts of the world based on assessments made 50 years ago, could in fact add to a person's calorie intake. When xanthan gum was first introduced, it was thought that the additive went straight through the body without affecting the person who ate it. But now the researchers noted that we are starting to see long-term effects of xanthan gum that were not seen earlier. "We only see these changes in gut bacteria of people eating a 'westernised diet' where processed foods and additives make up a significant part of the food intake. For example, we do not see the same changes in indigenous people from different parts of the globe who eat limited amounts of processed foods," La Rosa explained. "Based on this study, we cannot conclude if and how xanthan gum affects our health. But we can say that the additive affects the microbiota in the gut of people who consume it through food," she added. The researchers called for more research to understand the impact of xanthan gum on the human gut. Read More► Eating More Mushrooms May Be Good For Your Gut Health

Ultra-processed foods are having a negative impact on the diversity of plant species available for human consumption while also damaging human and planetary health, according to a commentary published in the journal BMJ Global Health. Ultra-processed foods such as sweetened or salty snacks, soft drinks, instant noodles, reconstituted meat products, pre-prepared pizza and pasta dishes, biscuits and confectionery, are made by assembling food substances, mostly commodity ingredients, and 'cosmetic' additives (notably flavours, colours and emulsifiers) through a series of industrial processes. Nutrition experts from Brazil, the US and Australia have investigated the issue and warned that these products are the basis of a 'globalised diet' and are becoming dominant in the global food supply, with sales and consumption growth in all regions and almost all countries, particularly in the upper-middle-income and lower-middle-income countries. According to the experts, the global agrobiodiversity - the variety and variability of animals, plants and microorganisms used directly or indirectly for food and agriculture is declining, especially the genetic diversity of plants used for human consumption. Peoples' diets are becoming less diverse, with ultra-processed foods replacing the variety of whole foods necessary for a balanced and healthy diet. As much as 90 per cent of humanity's energy intake comes from just 15 crop plants, and more than four billion people rely on just three of them - rice, wheat and maize. Production of ultra-processed foods involved greater use of ingredients extracted from a handful of high-yielding plant species (such as maize, wheat, soy and oil seed crops) which meant that animal-sourced ingredients used in many ultra-processed foods were often derived from confined animals fed on the same crops. Another issue of concern was that ultra-processed food production used large quantities of land, water, energy, herbicides and fertilisers, causing environmental degradation from greenhouse gas emissions and accumulation of packaging waste. "The very rapid rise of ultra-processed foods in human diets will continue to place pressure on the diversity of plant species available for human consumption," said Fernanda Helena Marrocos Leite, from the School of Public Health at University of Sao Paulo in Brazil, and her team. "Future global food systems fora, biodiversity conventions and climate change conferences need to highlight the destruction of agrobiodiversity caused by ultra-processed foods, and to agree on policies and actions designed to slow and reverse this disaster," Leite added. Read More► Intake of Diversified Nutrients in Balanced Diet Vital for Healthy Life

London: Though SARS-CoV-2, virus causing Covid-19, majorly causes infections of the respiratory tract, it also affects other organs of the human body such as the eyes and brain. While there is growing evidence to show that coronaviruses can enter the retina of the eye, German researchers have now shown that the virus can also replicate in human eyes. According to the study, published in the Stem Cell Reports, SARS-CoV-2 actually infects retinal cells, especially retinal ganglion cells, but also light-sensitive cells. Furthermore, the researchers show that coronaviruses can also replicate in these cell types. This finding is new and underlines the need to monitor retinal pathologies as a possible consequence of 'Long Covid'. A team of researchers from the Max Planck Institute for Molecular Biomedicine and the Westfalische Wilhelms-Universitat Munster utilised organoids, an organ-like model system, of the retina from human reprogrammed stem cells to study SARS-CoV-2 infection of the retina. The retinal organoids were incubated with SARS-CoV-2 viruses and then using quantitative PCR analysis, the researchers succeeded in detecting Covid mRNA in the organoids, indicating that cells in the organoids were indeed infected by the virus. To measure the active virus concentrations produced by the infected organoids after different incubation times, the researchers used an assay called a "viral plaque assay". Indeed, the assay showed that new viral progeny has been formed in the retinal organoids. "This is the first demonstration that SARS-CoV-2 replicates in human retinal cells," said Thomas Rauen from Max Planck. To find out which cells in the retinal organoids are affected, the researchers analysed the organoids under a fluorescence microscope. With the help of different immune markers for the different cell types of the retina and with a fluorescent antibody against the nucleoprotein (N-protein) of SARS-CoV-2, they found that mainly two cell layers - inner and outer - of the retinal organoids were infected. The outer nuclear layer of the organoids contains the cell bodies of the photoreceptors -- the cones and rods that convert incoming light into nerve impulses. "However, the cell type in which we most frequently detected the N-protein of Sars-CoV-2 is retinal ganglion cells," Yotam Menuchin-Lasowski from the Institute. These cells are located in the innermost cell layer of the retina and transmit all signals from the retina to the brain via the optic nerve. Interestingly, many of the retinal symptoms associated with Covid-19 are related to retinal ganglion cells, but these have previously been associated predominantly with secondary effects of other Covid-induced disease symptoms, such as damage to blood vessels or an increase in eye pressure. "However, our current retina-organoid study shows that infection with SARS-CoV-2 can have direct pathological consequences for retinal ganglion cells, even though visual impairment is not common in patients with Covid-19," Rauen said. "But our data give us reason to believe that so-called long-Covid symptoms may include degenerative retinal disease." (agency) Read More► Natural Covid Antibodies Last 7 Months in Children: Study