The memory neurons produced in the laboratory from stem cells
Alzheimer's autrefléau Medellín
The anti-Alzheimer revalued
The memory neurons produced in the laboratory from stem cells
Posted: March 9, 2011 03:01 PM PST
This world premiere could open the door to important medical advances in the treatment of Alzheimer's disease.
CHLOE by DURAND-PARENTI
It is a scientific feat of nature to generate new hope for medicine. After six years of work, U.S. researchers at the University of Chicago in the United States, for the first time, managed to recreate in the laboratory of cholinergic neurons from embryonic stem cells. These neurons, which play a fundamental role in the functioning of memory, those most affected in some degenerative diseases such as Alzheimer's disease or dementia with Lewy bodies. The scientific team headed by Dr. Jack Kessler and his deputy Christopher Bissonnette then reimplanted cholinergic neurons "manufactured" in the hippocampus of mice to check successfully that they were very functional. Thence to imagine neurons that can replace cells destroyed by disease, there is only one step ...
"This research holds out hope for the future, but we can still not get carried away: the use of these neurons in humans is probably not for tomorrow," moderates the neurologist Bernard Croisile , chief of neuropsychology at the hospital-Pierre Wertheimer Lyon.
"The neurons are located in a part of the brain, the nucleus of Meynert, easily accessible: one can not ask a surgeon to open the brain and to access this area," he says. "We must therefore consider using a precise technique, and non-invasive surgery such as stereotactic (image-guided technique) to stick a needle in an attempt to implement these neurons in the deep region of the brain or try to inject by lumbar puncture or ventricular puncture, "said the specialist. "After that, it will still that these neurons are viable and they can actually, since the nucleus of Meynert, rebuild networks and effectively develop their potential cholinergic throughout the brain," he insists.
Until a technical solution transplantation may eventually be found, researchers at the University of Chicago in the United States has much to use their discovery to advance medical research. They thus wish to test cholinergic neurons on their "manufactured" a whole battery of drugs used in treating Alzheimer's disease. They also hope to use them to understand the mechanisms of degeneration that leads to their death. Data that could eventually allow the development of preventive therapies. A major issue in Western countries with an aging population. In France alone, 860,000 people are affected by Alzheimer's disease or related diseases.
Study published in the journal American Stem Cells
Alzheimer's autrefléau Medellín
Posted: March 8, 2011 10:21 PM PST
By MICHEL SIZE Envoy in Copacabana
WIDE ANGLE-In Colombia, a family is affected, for generations, the degenerative disease. Researchers have identified the gene that fails, try to develop a vaccine.
There are still twenty seconds, she smiled, sitting on the sofa in his house, waving two toys to children in their nervous hands. Familiar faces to meet his smiles. But they turned away, far away from their conversation, and now exchange them for serious words that echo in the room with bare walls, ceiling down. "No cure is possible. Her mother is already dead, his brother is sick. Tomorrow, children can be? "A tremor seized his chin. She mumbles a few words without a logical thread of voice tormented by anxiety. Near her, a young woman, her daughter reassured her, stroking her face. On the other hand, a child is clinging to his neck. "Do not cry, Grandma!" Luz Yolanda looks without seeming to understand. At 49 years, the Colombian has Alzheimer's for ten years. At first his family were alerted by his small oversights by the succession of things she said suddenly unavailable in their home in Copacabana, a half-hour drive from Medellin. They recognized the degenerative disease that is decimating their families. An incurable disease, which overwhelms them for generations, but paradoxically they could help treat.
Loss of language and prostration
Luz Yolanda face, his uncle Hector, not much older, is the account without flinching: besides his own mother, five of his eleven brothers and sisters were beaten, several of his nephews, cousins. In November 2010, says a former pharmacist, his brother Arnulfo died at his home after sixteen years of illness. "We're doing better now," he admits. At one point we had to take care of four patients at a time! It's exhausting. "Beside him, the brother of Luz Yolanda, more moderately affected, repeating words of welcome, smiling good-naturedly. But everyone knows that her condition can only decline, until the loss of language and prostration in bed.
The family originated from Angostura, a Colombian village of Antioquia, the region which Medellin is the capital. It is in this sector of the Andes has been identified in several villages, a genetic deformity that affects 25 branches of the family as that of Hector. This mutation, a gene located on chromosome 14, is "autosomal dominant": "Each child of a carrier has a 50% chance of having to turn, and all carriers are bound to develop the disease," explains Francisco Lopera, team coordinator of Neurosciences of the University of Antioquia, originally discovered.
An exceptional location: the vast majority of cases of Alzheimer's in the world appears in a "sporadic" No impact hereditary demonstrated. The anomaly, popularized under the name "mutación paisa", the name given to the people, leads to another curse. It affects patients from 44 years on average - against 65 for the traditional form. Hector even worried to see his relatives with younger and younger: a sister and 34, nephews and 35. Himself, at age 61, believes it to be pulled: the disease, he was the bearer, has already had to declare.
Dr. Lopera first suspected the existence of a mutation. As a young neurologist, he received a 47 years already affected, with several dead relatives from the same disease. Launched in 1995, research has been to identify the faulty gene and identification of affected families, all from a common trunk. Peeling baptism and notarial archives, researchers are raised up a couple "original" of Spaniards, who had led the mutation and dispersed in 1750. It has remained concentrated in the area - even though immigrants have brought to Canada today - because of the very specific colonization of the region.
The Indians were almost exterminated during the Conquest, and the area has been repopulated with virtually no interbreeding with Europeans. These pioneers, isolated hamlets closest hour by mule to the side of the Andes, lived among them. It is common to find around Angostura or near the neighboring village of Yarumal, marriages between cousins who gave birth to a sibling group of ten or twelve children.
A vaccine testing suspended
This unique concentration has attracted the attention of researchers worldwide who collaborate with the University of Antioquia: neuroscience center in Cuba, the universities of Boston and Hamburg, French and Spanish groups ... For reviews blood, the university has been identified 500 carriers of the genetic mutation, healthy and sick. Those among them who still have no symptoms are a population "ideal" to test a preventive care for Alzheimer's, more credible in the eyes of Francisco Lopera. "The trials of therapies to cure people already affected have a very high failure rate," he recalls. His cohort of potential patients waiting feverishly time trials.
"I'll do whatever the team asks me to university," swear Alejandra, daughter of Luz Yolanda. At 20 years, including several years caring for her sick parents, she "really wanted to study" one day. She does not know if she carries the mutation: the university, in agreement with patients, does not give those with whom she has found the defective gene. "Why would I?" She says, shaking her mother's hand. I would sink into psychosis, and perhaps even that I would develop the disease faster. "
Alejandra is a little disappointed: clinical trials, which were to begin this year, will start only next year. Francisco Lopera, who wants a product "very safe and effective" for its patients, afraid of the history. In 2001, a test vaccine was suspended after causing several encephalitis. The doctor piercing gaze and leonine hair does not want that to his patients.
"He cares for us restless," says Gloria Piedrahita, a retired nurse and young Yarumal. In the house she shares with her mother, she supported herself with energy of a brother and sister prostrate on their chair. She changes sides every two hours to avoid bedsores, talk to them tenderly and dusts the pictures on the wall, remember the mocking pout and the determined look of her elder sister before the illness. "I wish the drug to be ready in time for him," she laments, pointing to a younger brother, already reached, which comes and goes in the room mechanically by sliding a ring on her finger.
The urgency of a sure cure
For the tests, the team investigating the use of a vaccine that inhibits the development of beta-amyloid protein fragments involved in the death of neurons in the covering plate, until losing to the brain third weight. No final result will not be known until 2015, warns Dr. Lopera, "and this may be a failure." But any success would open a huge hope to curb the spread of disease worldwide. With an aging population, 35.6 million people with dementia - Alzheimer's disease from which is the main cause - could be three times higher in 2050. And developing countries will host while seven patients out of ten. Hence the urgent need for a sure cure, and if possible, cheap. As everywhere, Dr. Lopera can give patients diagnosed as drugs that slow the progression of evil, or relieve: pills against depression, against convulsions that accelerate the death of neurons.
It's already a huge step forward. There are another twenty years, nobody in the country really knew whence the disease. "We just called it the silliness," recalls Gloria, who grew up on a farm. The peasants clearly understood that there was a history of heredity, but they blended a multitude of beliefs: a priest or enemy had cast a curse on the family, the patient had brushed against a mysterious tree, drank a source poisoned, hit another patient ... "I counted at least 80 myths of this kind," says Lucia Madrigal, a native of Yarumal psychologist. The care was at such superstitions. Gloria remembers the despair of his grandmother, locked in a room, a cousin in an abandoned barn and fed by neighbors. "Before the arrival of Dr. Lopera, patients were dying of malnutrition or bedsores after five years, through ignorance," adds Evelio Lopez, a physician at the hospital Yarumal. But now, he assures the day-care training from the University are packed house in the village. In the dressing Lopera, Beatriz patient to obtain medications. In October, she and her family participated in a series of tests to which the professor submits some 2000 affected family members, whether or not affected by the mutation. The sequence of words to memorize - "hut - beach - queen - Notes", to reproduce drawings accompanied by simple questions, which seemed as much fun exercises, have betrayed the first signs of disease in his mother. "I feel more stupid," repeat it to her daughter. Beatriz tries to cheer him up, but hardly surprised: "In our families, we must prepare for everything," she says soberly.
The evening is now well advanced Yarumal, and mist of the mountains the temperature has cooled. In the house of Gloria, the youngest brother looks on paper by turning the ring without end. In one room, like every night, the nurse asks aloud to the elder, rosary in hand. Gloria smiles, kisses. Her nephews, she believes, will escape all that.
The anti-Alzheimer revalued
Posted: March 8, 2011 10:05 pm PST
Some doctors believe the anti-Alzheimer drugs ineffective and not devoid of side effects. The High Authority for Health has decided to expedite the review of these products and must give its opinion in June.
The anti-Alzheimer drugs are they any good? And their risk-benefit balance is it always positive? These issues are now at the heart of a debate that goes in the health sector. Some doctors, in words more or less covered, after entrusting the Mediator, the next "big thing" on the drug could affect these products against dementia.
"Without going so far, one may wonder," says Dr. Claude Leicher, union president of General MG France. "Today, the community spends large sums of money (260 million euros in 2009) to reimburse drugs ineffective and whose toxicity, including cardiovascular, raises doubts," added the doctor. These critics are not unanimous among neurologists or geriatricians. "To say that these therapies are useless or even dangerous risks creating patients and their relatives concern entirely unjustified," replied Dr. Jean-Marie Vetel, a geriatrician at the Hospital of Le Mans and a member of the Committee transparency of the High Authority for Health (HAS). The latter does not take very least the debate seriously.