When infections occur in the body, stem cells in the blood often jump into action by multiplying and differentiating into mature immune cells that can fight off illness. But repeated infections and inflammation can deplete these cell populations, potentially leading to the development of serious blood conditions such as cancer.
Now, a team of researchers led by biologists at the California Institute of Technology (Caltech) has found that, in mouse models, the molecule microRNA-146a (miR-146a) acts as a critical regulator and protector of blood-forming stem cells (called hematopoietic stem cells, or HSCs) during chronic inflammation, suggesting that a deficiency of miR-146a may be one important cause of blood cancers and bone marrow failure.
While looking for mechanisms that might be relevant to restoring regenerative potential in older skeletal muscle, HSCI Executive Committee member, Amy Wagers, PhD, and her team, thought about mechanisms that had been studied for a long time evolutionarily as regulating lifespan and longevity. One example of such a mechanism is reduced calorie intake in the absence of malnutrition, also know as calorie restriction, which has been show to extend lifespan in many organisms.
In order to address the question of whether calorie restriction could also affect skeletal muscle regeneration, Wagers and her colleagues placed mice for 12 weeks on a calorie restricted diet. When the animals were challenged with muscle damage, they responded more vigorously and repaired the damage more rapidly and more effectively than the control mice.
Scientists have for the first time succeeded in extracting vital stem cells from sections of vein removed for heart bypass surgery. Researchers funded by the British Heart Foundation (BHF) found that these stem cells can stimulate new blood vessels to grow, which could potentially help repair damaged heart muscle after a heart attack.
The research, by Paolo Madeddu, Professor of Experimental Cardiovascluar Medicine and his team in the Bristol Heart Institute (BHI) at the University of Bristol, is published in the leading journal Circulation.
Though the world’s attention has focused on Iran‘s advancing nuclear program, Iranian scientists have moved to the forefront in embryonic stem cell research, according to a recent joint study by Harvard University and the Massachusetts Institute of Technology.
Controversial in the United States, embryonic stem cell research was embraced in 2002 by Ayatollah Ali Khamenei, Iran’s conservative religious leader. President Obama has recently adopted a similar policy, reversing restrictions that George W. Bush’s administration imposed because of the implications for destroying potential human lives.
Stem cells have been shown to have significant capability to develop into a plethora of different cell types and work as a repair system to replenish cells with specialized functions.
“Islam is very compatible with the modern sciences,” said Hassan Ashktorab of the Howard University Cancer Center. “Policies that may be classified as liberal in the American political system seem to be common sense to Iranian politicians.”
The addition of two particular gene snippets to a skin cell’s usual genetic material is enough to turn that cell into a fully functional neuron, report researchers from the Stanford University School of Medicine. The finding, published online July 13 in Nature, is one of just a few recent reports of ways to create human neurons in a lab dish.
The new capability to essentially grow neurons from scratch is a big step for neuroscience research, which has been stymied by the lack of human neurons for study. Unlike skin cells or blood cells, neurons are not something that’s easy for a living human to donate for research.
“A major problem in neurobiology has been the lack of a good human model,” said senior author Gerald Crabtree, MD, professor of pathology and of developmental biology. “Neurons aren’t like blood. They’re not something people want to give up.”
Generating neurons from easily accessible cells, such as skin cells, makes possible new ways to study neuronal development, model disease processes and test treatments.
It also helps advance the effort, still in its infancy, to replace damaged or dead neurons with new ones.