Stem cell therapies for the scourges of old age are on the near horizon. Will they come in time for the Baby Boomers?
No amount of Botox or Pilates can stave off the loss of brain cells, a steady erosion that began, ironically, in the days when we were part of the Woodstock nation. The brain reaches its maximum weight by age 20 and then slowly starts shrinking, losing 10 per cent or more of its volume over a lifetime. By our 50s, we’re experiencing mild mental glitches, those unsettling ‘senior moments’ when we’ve misplaced the keys for the umpteenth time or can’t remember the name of an acquaintance, all of it symptomatic of the steady erosion of neurons in our brains.
We make feeble jokes about our failing memories, but quietly worry that they are harbingers of something worse – such as scourges from dementia to Parkinson’s, which increase in frequency as we age. No matter how it manifests, the progressive shrinkage of our brain and the faulty wiring in our neural circuitry slowly rob us of our memories, identity and personality, the abilities that give our lives meaning and purpose, and the physical and emotional capacity to fully embrace the world.
All this is magnified by the demographic time bomb that threatens to exhaust society’s resources: by 2050, more than 400 million people worldwide will be aged over 80, many caring for the explosion of friends and family suffering from brain afflictions of varying kinds. The burden could bankrupt our health system – or, new technology based on neural stem cells, the progenitor cells of the nervous system, could intervene, reversing neurodegeneration, healing damaged brains and averting catastrophe in the nick of time. (...)
A team researching Alzheimer’s at the University of California, Irvine has shored up memory by transferring stem cells to the brains of mice. To do their work, they compared the performance on a simple memory test of a group of healthy mice with ones who were genetically altered to develop brain lesions that mimic Alzheimer’s. The fit mice remembered their surroundings about 70 per cent of the time, while the recall rate for the impaired animals was a scant 50 per cent. Scientists then injected the hippocampus – the brain region responsible for memory storage – of the injured mice with 200,000 neural stem cells that were engineered to glow green under an ultraviolet light so their progress could be tracked. Three months later, when both groups of mice were given the same test, they scored the same – about 70 per cent recall – while a control group of damaged mice that didn’t receive the stem cells still had significant mental deficits.
Significantly, only a handful – about 6 per cent – of the implanted cells were transformed into neurons, so the beneficial effects didn’t occur because they simply replaced dead cells. Yet there was a 75 per cent increase in the number of synapses – the connections between neurons that relay nerve impulses. Subsequent experiments suggest the stem cells release a protein called brain-derived neurotropic factor (BDNF) that seems to nurse the injured neurons back to health by keeping them alive and functional, and prompt the surrounding tissue to produce new neurites (long, thin structures called axons and dendrites that transmit electrical messages).
In replications of these studies at labs around the world, treated lab animals showed improvements even after months – roughly the equivalent of about a decade in human years. ‘The stem cells were acting as a fertiliser of sorts for the surviving cells,’ says Mathew Blurton-Jones, a neuroscientist at the University of California, Irvine involved in the research. When scientists artificially reduced the amount of BDNF the stem cells produced, the benefit disappeared too. (...)
A dose of stem cells delivered to just the right sweet spot could mend the fractured neural circuits that ferry signals throughout the brain, holding promise for relief of psychiatric diseases from bipolar disorder to schizophrenia. The technology might one day ease learning disabilities, including deficits in information processing and attention. But the application closest at hand is the one that could rescue the boomer generation, my friends, and me, from the looming loss of our memories, our social skills, and our very selves. One day soon, neural stem cells will be used like brick and mortar to shore up the crumbling walls in our brains and restore lost functions so we’re almost good as new. ‘We can change the face of therapeutics with neural stem cells,’ says Eva Feldman, a neurologist at the University of Michigan who is a leading stem cell researcher. ‘They’re like chicken soup for the brain.’
We make feeble jokes about our failing memories, but quietly worry that they are harbingers of something worse – such as scourges from dementia to Parkinson’s, which increase in frequency as we age. No matter how it manifests, the progressive shrinkage of our brain and the faulty wiring in our neural circuitry slowly rob us of our memories, identity and personality, the abilities that give our lives meaning and purpose, and the physical and emotional capacity to fully embrace the world.All this is magnified by the demographic time bomb that threatens to exhaust society’s resources: by 2050, more than 400 million people worldwide will be aged over 80, many caring for the explosion of friends and family suffering from brain afflictions of varying kinds. The burden could bankrupt our health system – or, new technology based on neural stem cells, the progenitor cells of the nervous system, could intervene, reversing neurodegeneration, healing damaged brains and averting catastrophe in the nick of time. (...)
A team researching Alzheimer’s at the University of California, Irvine has shored up memory by transferring stem cells to the brains of mice. To do their work, they compared the performance on a simple memory test of a group of healthy mice with ones who were genetically altered to develop brain lesions that mimic Alzheimer’s. The fit mice remembered their surroundings about 70 per cent of the time, while the recall rate for the impaired animals was a scant 50 per cent. Scientists then injected the hippocampus – the brain region responsible for memory storage – of the injured mice with 200,000 neural stem cells that were engineered to glow green under an ultraviolet light so their progress could be tracked. Three months later, when both groups of mice were given the same test, they scored the same – about 70 per cent recall – while a control group of damaged mice that didn’t receive the stem cells still had significant mental deficits.
Significantly, only a handful – about 6 per cent – of the implanted cells were transformed into neurons, so the beneficial effects didn’t occur because they simply replaced dead cells. Yet there was a 75 per cent increase in the number of synapses – the connections between neurons that relay nerve impulses. Subsequent experiments suggest the stem cells release a protein called brain-derived neurotropic factor (BDNF) that seems to nurse the injured neurons back to health by keeping them alive and functional, and prompt the surrounding tissue to produce new neurites (long, thin structures called axons and dendrites that transmit electrical messages).
In replications of these studies at labs around the world, treated lab animals showed improvements even after months – roughly the equivalent of about a decade in human years. ‘The stem cells were acting as a fertiliser of sorts for the surviving cells,’ says Mathew Blurton-Jones, a neuroscientist at the University of California, Irvine involved in the research. When scientists artificially reduced the amount of BDNF the stem cells produced, the benefit disappeared too. (...)
A dose of stem cells delivered to just the right sweet spot could mend the fractured neural circuits that ferry signals throughout the brain, holding promise for relief of psychiatric diseases from bipolar disorder to schizophrenia. The technology might one day ease learning disabilities, including deficits in information processing and attention. But the application closest at hand is the one that could rescue the boomer generation, my friends, and me, from the looming loss of our memories, our social skills, and our very selves. One day soon, neural stem cells will be used like brick and mortar to shore up the crumbling walls in our brains and restore lost functions so we’re almost good as new. ‘We can change the face of therapeutics with neural stem cells,’ says Eva Feldman, a neurologist at the University of Michigan who is a leading stem cell researcher. ‘They’re like chicken soup for the brain.’
by Linda Marsa, Aeon | Read more:
Image: Centre Jean Perrin/SPL
