Reverse? Abundant newborn neurons in the adult brain April 13, 2018 Source: DeepTech Deep Technology Previously, a paper published in Nature said that the adult hippocampus does not produce neurons. However, a new study published in the April 5 issue of Cell Stem Cell refuted this view. Researchers have discovered thousands of immature neurons in the brain. This finding is inconsistent with the recent results of "showing only a few immature neurons." If there are so many neurons, it means that adults also have neurogenesis. According to Cell Stem Cell, April 5, the adult hippocampus contains thousands of immature neurons. This result is contrary to the conclusion of an article published in Nature last month. The latter stated that no evidence of the presence of neural precursor cells or immature neurons was found in the adult brain. Such contradictory findings have led to doubts that researchers have not yet fully understood the cellular processes in the hippocampus of the adult brain's learning and memory center. Xinyu Zhao, a neurobiologist at the University of Wisconsin-Madison who did not participate in the study, said: "The debate on adult neurogenesis has been around for a long time." She said that the latest results of Cell Stem Cell are important because of its use. The gold standard for animal neuroneogenesis, stereology, is used to calculate immature and mature neurons in healthy human hippocampus. This method determines the number of individual cell types in a tissue when the sample has been cut into fragments. . “I have never seen anyone doing this in human tissue. This is mainly due to the availability of human tissue,†says Zhao. “More notably, this study uses a whole hippocampus.†In the new study, neuroscientist Maura Boldrini of Columbia University and colleagues examined 28 post-mortem brain tissues of healthy people aged 14 to 79 who died less than 26 hours. Considering that past studies have reported mixed results of new neuronal development in the brain of the elderly, the team wondered whether it could identify signs of neurogenesis in human brain tissue. To this end, the team quantified the abundance of specific proteins in hippocampal cells with labeled antibody staining: neural progenitor cells were labeled with GFAP, nestin and Sox2; intermediate neural progenitor cells were labeled with Ki-67 and nestin; immature Granular neurons were labeled with DCX and PSA-NCAM; mature granule neurons were labeled with NeuN. Previous studies in Nature also used the same markers to detect these different neuronal cells, but Baldrini noted that in the Nature article, some tissue samples died more than two days at the time of fixation, and the researchers did not conduct the entire hippocampus. an examination. Boldrini's team found that the anterior and middle (in the hippocampal neurogenesis) of the dentate gyrus of the elderly had a smaller neural precursor cell bank than the younger one. Despite this, the elderly have an average of about 1000 neural progenitor cells in the anterior, middle, and posterior regions of the dentate gyrus. The intermediate neural progenitor cells do not seem to decrease with age. All brain samples contain thousands of interneuronal progenitor cells. Not only that, the individual dentate gyrus of the elderly also contains thousands of immature neurons, suggesting that the rate of nerve formation may not decline due to aging. In addition, the researchers found a small number of abnormally morphological PSA-NCAM+ cells in the anterior dentate gyrus of the elderly. The team believes that this "may indicate a decline in neuroplasticity." Figure | Comparison of stained neural progenitor cells (pink) in young (left) and old (right) brains. Source: MAURA BOLDRINI Boldrini explained that if cells do not migrate or germinate dendrites (which may alter cell morphology), then these changes mean that cells will be difficult to integrate into existing circuits. In addition, the team found that the neovascularization of the anterior dentate gyrus of the elderly was less developed than in younger adults. Boldrini explains that the anterior dentate gyrus is connected to the amygdala responsible for fear and stress and is emotionally related. “This new result suggests that the front area may be more susceptible to aging,†she said. In this regard, the co-author of the Nature study, Shawn Sorrells and Mercedes Paredes of the University of California, San Francisco Institute (UCSF) wrote to The Scientist arguing: "(Although the new study) provides some interesting evidence to prove that the hippocampal vascular development in adults is declining But we questioned their use of cell staining as a way to prove the existence of new neurons in the adult brain." Sorrells and Paredes emphasized that identifying new neurons in the hippocampus is a major technical challenge. Although, in a recent study, they performed similar observations with Boldrini and colleagues, after extensive extensive analysis of the shape and appearance of the cells in question (including electron microscopy and gene expression), UCSF researchers determined In fact, these cells are not young neurons or neural progenitors, but rather completely different types of cells. “Based on the number of hypothetical young neurons indicated in this new study, we should be able to detect them easily if they do exist. Therefore, these cells are suspicious,†Sorrells and Mercedes wrote. "At the moment, we don't think this new study can incite our recent observations that this is very rare if neurogenesis can really continue in the adult hippocampus." Such staining tests or histological studies have limitations. For example, if the delay is long, such as a person's death and its tissue is fixed, the analysis is separated by a few days, then the protein level may be reduced. Different preparation methods may also lead to different results. "I will never rely on this method to determine whether neurogenesis exists," Zhao said. In addition, she recommends that researchers develop more new ways to track adult neurogenesis. Reference: https://?articles.view/articleNo/52230/title/Abundant-Neurogenesis-Found-in-Adult-Humans--Hippocampi/ Natural Field focus on produce Cosmetic Raw material, powder functions as an Antioxidant and whitening in cosmetic products. They can effectively treat freckles, old age spots, pigmentation, acne, delaying senescence and preventing ultraviolet radiation,absorbed by the skin through the cell membrane, and they are very effective as a cosmetic external applicatio. Skin-Whitening Cosmetic Ingredient,Skin-Whitening Powder,Skin-Whitening Extract,Skin Whitening Xi'an Natural Field Bio-Technique Co., Ltd. , https://www.naturalnf.com
