Evolution’s random mutations and natural selection – Forthright Magazine
▻http://forthright.net/2019/06/05/evolutions-random-mutations-natural-selection
Stem cells can serve as a metaphor illustrating a powerful idea regarding Darwin’s proposed mechanisms for evolution. Research reveals that random mutations and natural selection do transform species, however, at a surprising cost.
Cause of #cancer is written into DNA of tumours, scientists find, creating a ’black box’ for origin of disease
▻https://www.telegraph.co.uk/science/2019/04/15/cause-cancer-written-dna-tumours-scientists-find-creating-black
Even with lung cancer, it is not known just how much can be attributed to smoking and how much could be linked to other factors, such as living by a busy road, or inhaling pollutants at work.
But now scientists at Cambridge University and King’s College London have shown that tumours hold information like a ’black box’ pointing to the cause of disease.
They exposed stem cells to dozens of known carcinogens and recorded how each alters its DNA code as cancer forms. It provides a ‘fingerprint’ or ‘mutational signature’ of the underlying cause and could even show which was the biggest culprit.
Harvard Calls for Retraction of Dozens of Studies by Noted Cardiologist - The New York Times
▻https://www.nytimes.com/2018/10/15/health/piero-anversa-fraud-retractions.html
A prominent cardiologist formerly at Harvard Medical School and Brigham and Women’s Hospital in Boston fabricated or falsified data in 31 published studies that should be retracted, officials at the institutions have concluded.
The cardiologist, Dr. Piero Anversa, produced research suggesting that damaged heart muscle could be regenerated with stem cells, a type of cell that can transform itself into a variety of other cells.
Although other laboratories could not reproduce his findings, the work led to the formation of start-up companies to develop new treatments for heart attacks and stroke, and inspired a clinical trial funded by the National Institutes of Health.
“A couple of papers may be alarming, but 31 additional papers in question is almost unheard-of,” said Benoit Bruneau, associate director of cardiovascular research at the Gladstone Institutes in San Francisco. “It is a lab’s almost entire body of work, and therefore almost an entire field of research, put into question.”
With stem cells and #CRISPR, scientists breed mice with same-sex parents
▻https://www.statnews.com/2018/10/11/mice-same-sex-parents-stem-cells-crispr
Mammals still need both sets, though, to have their full suite of genetic instructions. IGF2, for example, is a gene crucial for growth and development, but only the paternal copy is normally active. If we just inherited DNA maternally then, we wouldn’t grow or develop properly; that gene would simply remain off. On the flip side, there are a number of these genes for which we rely on our mothers.
But scientists started challenging nature’s way a decade and a half ago. The trick was to cajole certain maternal genes to act like paternal genes in terms of their activity, or vice versa.
Does Aging Have a Reset Button ? - Issue 57 : Communities
▻http://nautil.us/issue/57/communities/does-aging-have-a-reset-button
Part of Vittorio Sebastiano’s job is to babysit a few million stem cells. The research professor of reproductive biology at Stanford University keeps the cells warm and moist deep inside the Lorry I. Lokey Stem Cell Research Building, one of the nation’s largest stem cell facilities. He’s joined there by an army of researchers, each with their own goals. His own research program is nothing if not ambitious: He wants to reverse aging in humans. Stem cells are the Gary Oldman of cell types. They can reprogram themselves to carry out the function of virtually any other type of cell, and play a vital role in early development. This functional reprogramming is usually accompanied by an age reset, down to zero. Sebastiano figures that if he can separate these different kinds of reprogramming, (...)
Scientists Discover a Bone-Deep Risk for Heart Disease - The New York Times
▻https://www.nytimes.com/2018/01/29/health/heart-disease-mutations-stem-cells.html
L’accumulation d’un clone de cellules souches hématopoïétiques mutées appelées « #CHIP » (pour « Clonal hematopoiesis of indeterminate potential »), apparaît tôt ou tard avec l’âge et est un facteur de risque indépendant d’#athérosclérose.
CHIP [...] increases a person’s risk of dying within a decade, usually from a heart attack or stroke, by 40 or 50 percent.
The condition becomes more likely with age. Up to 20 percent of people in their 60s have it, and perhaps 50 percent of those in their 80s.
But how might mutated white blood cells cause heart disease? One clue intrigued scientists.
Artery-obstructing plaque is filled with white blood cells, smoldering with inflammation and subject to rupture. Perhaps mutated white cells were causing atherosclerosis or accelerating its development.
In separate studies, Dr. Ebert and Dr. Walsh gave mice a bone-marrow transplant containing stem cells with a CHIP mutation, along with stem cells that were not mutated. Mutated blood cells began proliferating in the mice, and they developed rapidly growing plaques that were burning with inflammation.
“For decades people have worked on #inflammation as a cause of atherosclerosis,” Dr. Ebert said. “But it was not clear what initiated the inflammation.”
Now there is a possible explanation — and, Dr. Ebert said, it raises the possibility that CHIP may be involved in other inflammatory diseases, like arthritis.
New color-coding tool sheds light on blood disorders, cancers by tracking clonal stem cells
News Medical Life Sciences
▻http://www.news-medical.net/news/20161122/New-color-coding-tool-sheds-light-on-blood-disorders-cancers-by-tracki
A new color-coding tool is enabling scientists to better track live blood stem cells over time, a key part of understanding how blood disorders and cancers like leukemia arise, report researchers in Boston Children’s Hospital’s Stem Cell Research Program.
In Nature Cell Biology they describe the use of their tool in zebrafish to track blood stem cells the fish are born with, the clones (copies) these cells make of themselves and the types of specialized blood cells they give rise to (red cells, white cells and platelets). Leonard Zon, MD, director of the Stem Cell Research Program and a senior author on the paper, believes the tool has many implications for hematology and cancer medicine since zebrafish are surprisingly similar to humans genetically.
[...]
“It’s like an RGB television set, where red, blue and green give you the whole spectrum of colors,” explains Zon. “In our system, the enzyme cuts out different parts —blue, for example, or green and blue — so the stem cell will end up a different shade of color. In this way, we were able to mark each stem cell being born with a different color, and then follow the colors through development and see how many stem cells of each color were present in the adult fish.”
Other scientists have developed tracking systems based on genetic “barcodes.” But these require dissecting the cells, so cannot analyze living, circulating cell populations.
Stanford researchers ‘stunned’ by stem cell experiment that helped stroke patient walk
▻https://www.washingtonpost.com/news/to-your-health/wp/2016/06/02/stanford-researchers-stunned-by-stem-cell-experiment-that-helped-str
Des #cellules_souches de la moelle osseuse dont le mode d’action ne se fait pas via leur transformation en tissu nerveux.
While the research involved only 18 patients and was designed primarily to look at the safety of such a procedure and not its effectiveness, it is creating significant buzz in the neuroscience community because the results appear to contradict a core belief about brain damage — that it is permanent and irreversible.
The results, published in the journal Stroke, could have implications for our understanding of an array of disorders including traumatic brain injury, spinal cord injury and Alzheimer’s if confirmed in larger-scale testing.
The work involved patients who had passed the critical six-month mark when recoveries generally plateau and there are rarely further improvements. [...]
The one-time therapy involved surgeons drilling a hole into the study participants’ skulls and injecting stem cells in several locations around the area damaged by the stroke. These stem cells were harvested from the bone marrow of adult donors. While the procedure sounds dramatic, it is considered relatively simple as far as brain surgery goes. The patients were conscious the whole time and went home the same day.
[...]
“Their recovery was not just a minimal recovery like someone who couldn’t move a thumb now being able to wiggle it. It was much more meaningful. One 71-year-old wheelchair-bound patient was walking again,” said [Gary] Steinberg [the study’s lead author and chair of neurosurgery at Stanford] who personally performed most of the surgeries.
[...]
Steinberg said that the study does not support the idea that the injected stem cells become neurons, as has been previously thought. Instead, it suggests that they seem to trigger some kind of biochemical process that enhances the brain’s ability to repair itself.
“A theory is that they turn the adult brain into the neonatal brain that recovers well,” he explained.
[...]
Nicholas Boulis, a neurosurgeon and researcher at Emory University, said the study appears to support the idea that there may be latent pathways in the brain that can be reactivated — a theory that has been “working its way to the surface” over the past few years.
#AVC
Dead could be brought ’back to life’ in groundbreaking project
▻http://www.telegraph.co.uk/science/2016/05/03/dead-could-be-brought-back-to-life-in-groundbreaking-project
A groundbreaking trial to see if it is possible to regenerate the brains of dead people, has won approval from health watchdogs.
A biotech company [#Bioquark] in the US has been granted ethical permission to recruit 20 patients who have been declared clinically dead from a traumatic brain injury, to test whether parts of their central nervous system can be brought back to life.
Scientists will use a combination of therapies, which include injecting the brain with stem cells and a cocktail of peptides, as well as deploying lasers and nerve stimulation techniques which have been shown to bring patients out of comas.
The trial participants will have been certified dead and only kept alive through life support. They will be monitored for several months using brain imaging equipment to look for signs of regeneration, particularly in the upper spinal cord - the lowest region of the brain stem which controls independent breathing and heartbeat.
The team believes that the brain stem cells may be able to erase their history and re-start life again, based on their surrounding tissue – a process seen in the animal kingdom in creatures like salamanders who can regrow entire limbs.
… oui, je me suis posé la question du mode de recueil de leur #consentement_éclairé indispensable à tout #essai_clinique
Functional human hearts regenerated from skin cells - CNET
▻http://www.cnet.com/au/news/functional-human-hearts-regenerated-from-skin-cells
A team of researchers has used adult skin cells to regenerate functional human heart tissue, a major step forward in bioengineering organs.
The day that heart transplant patients no longer need to wait for a donor match just got a little closer. Researchers from Massachusetts General Hospital have successfully grown functional heart tissue from stem cells created from skin cells. Their paper has been published in the journal Circulation Research.
The team’s technique potentially allows heart tissue to be built with the patient’s own cellular material, which reduces the need for an exact donor match, and also vastly lowers the chance of immunorejection.
Bioengineering Human Myocardium on Native Extracellular Matrix
▻http://circres.ahajournals.org/content/118/1/56
Abstract
Rationale: More than 25 million individuals have heart failure worldwide, with ≈4000 patients currently awaiting heart transplantation in the United States. Donor organ shortage and allograft rejection remain major limitations with only ≈2500 hearts transplanted each year. As a theoretical alternative to allotransplantation, patient-derived bioartificial myocardium could provide functional support and ultimately impact the treatment of heart failure.
Objective: The objective of this study is to translate previous work to human scale and clinically relevant cells for the bioengineering of functional myocardial tissue based on the combination of human cardiac matrix and human induced pluripotent stem cell–derived cardiomyocytes.
Methods and Results: To provide a clinically relevant tissue scaffold, we translated perfusion-decellularization to human scale and obtained biocompatible human acellular cardiac scaffolds with preserved extracellular matrix composition, architecture, and perfusable coronary vasculature. We then repopulated this native human cardiac matrix with cardiomyocytes derived from nontransgenic human induced pluripotent stem cells and generated tissues of increasing 3-dimensional complexity. We maintained such cardiac tissue constructs in culture for 120 days to demonstrate definitive sarcomeric structure, cell and matrix deformation, contractile force, and electrical conduction. To show that functional myocardial tissue of human scale can be built on this platform, we then partially recellularized human whole-heart scaffolds with human induced pluripotent stem cell–derived cardiomyocytes. Under biomimetic culture, the seeded constructs developed force-generating human myocardial tissue and showed electrical conductivity, left ventricular pressure development, and metabolic function.
Conclusions: Native cardiac extracellular matrix scaffolds maintain matrix components and structure to support the seeding and engraftment of human induced pluripotent stem cell–derived cardiomyocytes and enable the bioengineering of functional human myocardial-like tissue of multiple complexities.
Curing multiple sclerosis
▻http://www.economist.com/news/science-and-technology/21688848-stem-cells-are-starting-prove-their-value-medical-treatments-cur
Un exemple objectif (et potentiellement très dangereux comme expliqué plus bas) d’une #vulgarisation scientifique erronée.
Stem Cell Transplant in Multiple Sclerosis : Next Steps
▻http://www.medscape.com/viewarticle/859546
Benjamin Segal, MD, the Holtom-Garrett Professor of Neurology and director of the Multiple Sclerosis Center at the University of Michigan Medical School, Ann Arbor, added in an interview with Medscape Medical News, “Every time I’m in clinic I am asked about stem cells. There are private companies out there that exploit desperate people.”
“One of my patients with progressive MS went to Germany to get some type of intrathecal embryonic stem cell injection,” Dr Segal said. “A few months later, her husband informed me that she developed meningitis as a complication, and she died.”
Scientists Discover New Class of Sound Wave, Could Let Us Inhale Vaccines - Futurism
▻http://futurism.com/links/new-class-of-sound-wave
▻http://futurism.com/wp-content/uploads/2016/01/sound-600x600.jpeg
The waves in question are known as “surface reflected bulk waves.” Surface reflected bulk waves are a combination of bulk sound waves and surface sound waves.
Bulk sound waves cause an object to vibrate as one, kind of like holding a carpet at one end and shaking it. In contrast, surface sound waves only cause the surface of the material to vibrate, like waves in an ocean. By combining the two, researchers have created a sound wave class that is far more powerful than either carpet shaking or crashing waves alone.
Previously, sound waves have not been gentle enough to manipulate stem cells. These new waves, though, won’t cause damage to the delicate cells.
Future Uses
Study co-author Dr. Amgad Rezk, from the Micro/Nano Research Laboratory at RMIT and his team created a device to utilize surface reflected bulk waves in medical devices. It’s called HYDRA (don’t worry- not like Marvel’s Hydra). It passes electricity through a chip, converting it into sound waves that can break the liquid into an inhale-able spray.
Scientists create human stem cells through cloning | Reuters
▻http://in.reuters.com/article/2013/05/15/science-stemcells-idINDEE94E0DN20130515
... the achievement could also revive fears of reproductive cloning, or producing genetic copies of living (or dead) individuals.
Even before the study was published, a British watchdog group called Human Genetics Alert protested the research.
“Scientists have finally delivered the baby that would-be human cloners have been waiting for: a method for reliably creating cloned human embryos,” said Dr. David King, the group’s director. “This makes it imperative that we create an international legal ban on human cloning before any more research like this takes place. It is irresponsible in the extreme to have published this research.”
Among scientists, however, the accomplishment is being hailed as “a tour de force,” as stem cell biologist George Daley of the Harvard Stem Cell Institute put it. “This represents an unparalleled achievement. They succeeded where many other groups failed, including mine.”
The Embedded Dangers of Untested Stem Cell Cosmetics | Scientific American
►http://www.scientificamerican.com/article.cfm?id=stem-cell-cosmetics&WT.mc_id=SA_WR_20121219
@beautefatale des cellules souches injectées dans la peau du visage peuvent se transformer en os…
About three months earlier the woman had opted for a relatively new kind of cosmetic procedure at a different clinic in Beverly Hills—a face-lift that made use of her own adult stem cells. (...)
Six and a half hours of surgery later, he and his colleagues had dug out small chunks of bone from the woman’s eyelid and tissue surrounding her eye, which was scratched but largely intact. The clicks she heard were the bone fragments grinding against one another.
Rick Perry, prayer and stem cells: Unexpected consequences | The Economist
►http://www.economist.com/node/21525940?fsrc=scn/tw/te/ar/unexpectedconsequences
ast month Mr Perry had an operation to fix a recurring back problem. While the surgeon was at it, he injected the governor with stem cells, in an experimental procedure meant to speed recovery.
Pro-life conservatives oppose embryonic stem-cell research on the grounds that it destroys life. They are keen, however, on adult stem cells, which they hope may obviate the use of the embryonic kind. The stem cells used in Mr Perry’s procedure were his own. And the governor has been a proponent of adult stem-cell research, for economic reasons as well as ethical ones. If such treatments gain federal approval, and become more popular, Texas could be a centre of that industry.