FY 2011 Innovative Drug Approvals -35 new drugs (To download detail report: (www.biopreneur.org)
In a report released today, FY 2011 Innovative Drug Approvals, the FDA provided details of how it used expedited approval authorities, flexibility in clinical trial requirements and resources collected under the Prescription Drug User Fee Act (PDUFA) to boost the number of innovative drug approvals to 35 for the fiscal year (FY) ending Sept. 30, 2011. The approvals come while drug safety standards have been maintained.
Thirty-four of 35 were approved on or before the review time targets agreed to with industry under PDUFA, including three cancer drugs that FDA approved in less than six months. Seven of the new medicines provide major advances in cancer treatment; ten are for rare or “orphan”; three were approved using “accelerated approval,” diseases; one for melanoma and one for lung cancer
Sunday, November 6, 2011
Friday, September 16, 2011
Effect of Abuse and Neglect on Brain Development during Early Childhood
Effect of Abuse and Neglect on Brain Development during Early Childhood
Ryan Baidya and S.Samy (California Takshila University)
Being an infant, a toddler, is a growth stage in our lives where we absorb most things happening to or around us. We learn what we experience which activates and develops our brain and nervous system along the way. Happiness love and nurture promote positivity in child’s physical, cognitive, social and academic growth, utilizing their brain capabilities. An abused and neglect have adverse impacts on the child's physical, cognitive, emotional, and social growth.
Brain development is a lifetime process but it is said during childhood that the brain matures and fully develops to function throughout life.
According to researchers, the human brain begins to form three weeks after conception even then at birth it is undeveloped and not all areas are organized and fully functional. We are born with the basic brain structure but a lot of the brain's development occurs during the first few years after birth. This process of growth or development, follow a sequential pattern from the "bottom up" (Perry, Pollard, Blakely, Baker & Vigilante, 1995; Perry 2000a).
As the brain develops, it grows larger and more dense. By the age of 3, a baby's brain has reached almost 90 percent of its adult size (Perry, 2000c). The growth in each region of the brain largely depends on receiving stimulation, which spurs activity in that region. This stimulation provides the foundation for learning.
Brain development during infancy and early childhood growth stage has been receiving a lot of research attention especially the effects of abuse and neglect. According to US Child Protective Services, approximately over 700,000 children are abused or neglected each year. "As you grow, the brain is essentially like a sponge. It's absorbing all kinds of experiences. So if a child is not held, touched, talked to, interacted with, loved, literally neurons do not make those connections, and many of them actually will die. Simple things like eye contact, touch, rocking and humming can make all the difference to a baby. It makes neurons grow, it makes them make connections. Then, it makes the brain more functional,” Dr. Perry says.
Neglect and abuse (emotional, physical and sexual) have immediate and long-term effect on a child’s development. The impact of maltreatment on a child’s developing brain causes negative effects seen in a wide variety of areas including social, psychological, physical and cognitive development. The long-term effects of abuse and neglect of a child can be seen in higher rates of psychiatric disorders, increased rates of substance (drug) abuse, and a variety of severe relationship difficulties.
Dr. Perry also compares a brain scan of a normal, healthy 3-year-old child with a child who was severely neglected his first three years of life. "The first thing is that the brain is a little bit smaller. The brains of really severely neglected children tend to be smaller than the brains of children who have not been neglected," he says. "The brain didn't grow and shrink. It just didn't grow.
“These images illustrate the negative impact of neglect on the developing brain. In the CT scan on the left is an image from a healthy three year old with an average head size. The image on the right is from a three year old child suffering from severe sensory-deprivation neglect. This child’s brain is significantly smaller than average and has abnormal development of cortex.” These images are from studies conducted by a team of researchers from the Child Trauma Academy (www.ChildTrauma.org) led by Bruce D. Perry, M.D., Ph.D.
All rights for reproduction of the above image are reserved, Bruce Perry, MD., Ph.D. Baylor College of Medicine.
"As you grow, the brain is essentially like a sponge," Dr. Perry says. "It's absorbing all kinds of experiences. So if a child is not held, touched, talked to, interacted with, loved, literally neurons do not make those connections, and many of them actually will die." Simple things like eye contact, touch, rocking and humming can make all the difference to a baby, Dr. Perry says. "It makes neurons grow, it makes them make connections," he says. "Then, it makes the brain more functional."
The specific effects of maltreatment may depend on such factors as the age of the baby or child at the time of the abuse or neglect, whether the maltreatment was a one-time incident or prolonged occurrence, the identity of the abuser (e.g., parent or other adult), whether the child had a dependable nurturing individual in his or her life, the type and severity of the abuse, the intervention, and how long the maltreatment lasted. However, brief periods of moderate, predictable stress are not problematic; in fact, they prepare a child to learn and cope with the general world. The body's survival actually depends upon the ability to mount a response to stress (Shonkoff & Phillips, 2000).
Forming the Structure
The brain is made up of nerve cells also called neurons. At birth babies have almost all of the neurons more than 100 billion of them, although there is research that indicates some neurons are developed after birth and well into adulthood (Shonkoff & Phillips, 2000), the neurons babies have are primarily what they need to work with while growing up as children, adolescent, and adults.
Organizing the Structure
Brain development, is the process of generating, activating, strengthening, and discarding connections among the neurons; these connections are called synapses. Synapses, in the nervous system is a connection which allows a neuron to pass on information to other neurons, body muscles or glands.
It organizes the brain by forming neuronal pathways that connect the parts of the brain governing everything we do-from breathing and sleeping to thinking and feeling. The synapses present at birth are primarily those that govern our bodily functions such as heart rate, breathing, eating, and sleeping. Almost all other functions are developed as babies grow up into children and adults (Shore, 1997).
Daniel Siegel, medical director of the Infant and Preschool Service at the University of California, L.A., has found important links between interpersonal experiences and neurobiological development. There are clear links between neglect and abuse and later psychological, emotional, behavioral, and interpersonal disorders. The basis for this linkage is the impact that abuse and neglect have on brain development.
Generally the Left Hemisphere of the brain is the site of language, motor activity on the right side of the body, and logical thought based on language.
The Right Hemisphere of the brain is responsible for motor activity on the left side of the body, context perceptions, and holistic perception.
The Orbito-Frontal Cortex (the part of the brain directly behind the eyes) is responsible for integrating emotional responses generated in the limbic system with higher cognitive functions, such as planning and language, in the cerebral cortex’s prefrontal lobes.
The Left Orbito-Frontal Cortex is responsible for memory creation while the Right Orbito-Frontal Cortex is responsible for memory retrieval.
The Left and the Right Hemispheres of the Brain and its Processes
Healthy functioning requires an integrated right and left hemisphere. A substantial number of synaptic connections among brain cells develop during the first year of life. An integrated brain requires connections between the hemispheres by the Corpus Callosum.
Abused and neglected children have smaller Corpus Callosum than non-abused children. Abused and neglected children have poorly integrated cerebral hemispheres. This poor integration of hemispheres and underdevelopment of the Orbitofrontal Cortex is the basis for such symptoms as difficulty regulating emotion, lack of cause-effect thinking, inability to accurately recognize emotions in others, inability of the child to articulate the child’s own emotions, an incoherent sense of self and autobiographical history, and a lack of conscience.
Stressful experiences that are overtly traumatizing cause chronic elevated levels of neuroendocrine hormones. High levels of these hormones can cause permanent damage to the hippocampus, which is critical for memory. Based on this we can assume that psychological trauma can impair a person’s ability to create and retain memory and impede trauma resolution.
Abuse—Physical, Sexual, and Emotional
Abuse can refer to physical abuse, such as hitting, shaking, burning, or other forms of maltreatment that a parent or other caregiver might inflict. In the long-term, shaking can damage the fragile brain so that a child develops a range of sensory impairments, as well as cognitive, learning, and behavioral disabilities.
Emotional abuse generally refers to any ijury to a child's psychological or emotional stability (Child Welfare Information Gateway, 2008). Chronic stress may also qualify as emotional abuse. In some States, alcohol or substance abuse or domestic violence that affects the unborn child is considered child abuse. Physical abuse can cause direct damage to a baby's or child's developing brain. For instance, we now have extensive evidence of the damage that shaking a baby can cause.
According to the National Center on Shaken Baby Syndrome (2009), shaking can destroy brain tissue and tear blood vessels. In the short-term, shaking can lead to seizures, loss of consciousness, or even death.
Neglect—Lack of Stimulation
While chronic abuse and neglect can result in sensitized fear response patterns, neglect alone also can result in other problems. Malnutrition is a classic example of neglect. Malnutrition, both before and during the first few years after birth, can result in stunted brain growth and slower passage of electrical signals in the brain (Shonkoff & Phillips, 2000).
The most common form of malnutrition in the United States, iron deficiency, can affect the growing brain and result in cognitive and motor delays, anxiety, depression, social problems, and attention problems (Shonkoff & Phillips, 2000).
Although neglect often is thought of as a failure to meet a child's physical needs for food, shelter, and safety, neglect also can be a failure to meet a child's cognitive, emotional, or social needs. For example, babies need to experience face-to-face baby talk and hear countless repetitions of sounds in order to build the brain circuitry that will enable them to start making sounds and eventually say words. If babies' sounds are ignored repeatedly, their language may be delayed. These types of delays may extend to all types of normal development for neglected children, including their cognitive-behavioral, socio-emotional, and physical development (Scannapieco, 2008).
Global Neglect
Some specific long-term effects of abuse and neglect on the developing brain can include, (Teicher, 2000):
• Diminished growth in the left hemisphere, which may increase the risk for depression.
• Irritability in the limbic system, setting the stage for the emergence of panic disorder and posttraumatic stress disorder.
• Smaller growth in the hippocampus and limbic abnormalities, which can increase the risk for dissociative disorders and memory impairments
• Impairment in the connection between the two brain hemispheres, which has been linked to symptoms of attention-deficit/hyperactivity disorder.
Some causes of child abuse and neglect are:
• Today’s western, busy and career conscious lifestyle, single-parent and contemporary family societies.
- Both parents work either to meet the demands of their needs and wants or career is becomes more important than their children’s welfare.
- Parenting is considered old fashioned, low self-image and status in society. A parent does not have recognition or is thought not have a good future if one stays hone to look after their children till they start schooling. Contemporary families mostly do not have grandparents or other extended family members with them.
- Due to many similar reasons as stated above, children are sent to child care, nanny-care, and preschool. There are high chances that children left in these types of care, face neglect and in some cases even abuse.
• Unplanned/Teenage Pregnancy
- Inexperience in parenting, too young or not prepared for a child during that stage of their lives. Some parents or single moms are not willing to change their lifestyle and take up the responsibility; they also might not have support of their family or society.
• Domestic violence, poor relationship between parents, broken family
• Poverty, large family have lot of children to look after, lack of family planning , unemployment
We say that our children, the next generation are the future of our society, our country and the world. As adults, parents, family members/friends, guardian, teachers, it is our responsibility to ensure that children get the utmost care, love, attention, stable home environment, food and education to have a healthy and stable future, to become a mature, responsible adult.
How we mold these innocent and immature minds depend on their nurture, love and care they get from us. Educating adults, expecting parents, married couple, child - care takers and teachers on parenting and importance of child development and impact of abuse and neglect could be one of the solutions to reduce abuse and neglect on children. If an individual has gone through some abuse or neglect in their childhood they some say, their children might go through similar experiences but I say, why not learn from that past bad experience, put a stop to it by ensuring that their children doesn’t have to go through it.
Child care services can also play an important in reducing such occurrences by improving their services, ensuring that abused and neglected children get stable home environment and making adoption criteria more stringent. By the time child abuse and neglect are reported, most children have suffered to the extent that they start showing signs of it. Therefore to eliminate this problem parents and guardian need to learn and understand that their children’s safety and future lies in their hands.
References
http://www.childwelfare.gov/pubs/issue_briefs/brain_development/effects.cfm
http://teacher.scholastic.com/professional/bruceperry/abuse_neglect.htm
http://www.childwelfare.gov/can/impact/development/brain.cfm
Ryan Baidya and S.Samy (California Takshila University)
Being an infant, a toddler, is a growth stage in our lives where we absorb most things happening to or around us. We learn what we experience which activates and develops our brain and nervous system along the way. Happiness love and nurture promote positivity in child’s physical, cognitive, social and academic growth, utilizing their brain capabilities. An abused and neglect have adverse impacts on the child's physical, cognitive, emotional, and social growth.
Brain development is a lifetime process but it is said during childhood that the brain matures and fully develops to function throughout life.
According to researchers, the human brain begins to form three weeks after conception even then at birth it is undeveloped and not all areas are organized and fully functional. We are born with the basic brain structure but a lot of the brain's development occurs during the first few years after birth. This process of growth or development, follow a sequential pattern from the "bottom up" (Perry, Pollard, Blakely, Baker & Vigilante, 1995; Perry 2000a).
As the brain develops, it grows larger and more dense. By the age of 3, a baby's brain has reached almost 90 percent of its adult size (Perry, 2000c). The growth in each region of the brain largely depends on receiving stimulation, which spurs activity in that region. This stimulation provides the foundation for learning.
Brain development during infancy and early childhood growth stage has been receiving a lot of research attention especially the effects of abuse and neglect. According to US Child Protective Services, approximately over 700,000 children are abused or neglected each year. "As you grow, the brain is essentially like a sponge. It's absorbing all kinds of experiences. So if a child is not held, touched, talked to, interacted with, loved, literally neurons do not make those connections, and many of them actually will die. Simple things like eye contact, touch, rocking and humming can make all the difference to a baby. It makes neurons grow, it makes them make connections. Then, it makes the brain more functional,” Dr. Perry says.
Neglect and abuse (emotional, physical and sexual) have immediate and long-term effect on a child’s development. The impact of maltreatment on a child’s developing brain causes negative effects seen in a wide variety of areas including social, psychological, physical and cognitive development. The long-term effects of abuse and neglect of a child can be seen in higher rates of psychiatric disorders, increased rates of substance (drug) abuse, and a variety of severe relationship difficulties.
Dr. Perry also compares a brain scan of a normal, healthy 3-year-old child with a child who was severely neglected his first three years of life. "The first thing is that the brain is a little bit smaller. The brains of really severely neglected children tend to be smaller than the brains of children who have not been neglected," he says. "The brain didn't grow and shrink. It just didn't grow.
“These images illustrate the negative impact of neglect on the developing brain. In the CT scan on the left is an image from a healthy three year old with an average head size. The image on the right is from a three year old child suffering from severe sensory-deprivation neglect. This child’s brain is significantly smaller than average and has abnormal development of cortex.” These images are from studies conducted by a team of researchers from the Child Trauma Academy (www.ChildTrauma.org) led by Bruce D. Perry, M.D., Ph.D.
All rights for reproduction of the above image are reserved, Bruce Perry, MD., Ph.D. Baylor College of Medicine.
"As you grow, the brain is essentially like a sponge," Dr. Perry says. "It's absorbing all kinds of experiences. So if a child is not held, touched, talked to, interacted with, loved, literally neurons do not make those connections, and many of them actually will die." Simple things like eye contact, touch, rocking and humming can make all the difference to a baby, Dr. Perry says. "It makes neurons grow, it makes them make connections," he says. "Then, it makes the brain more functional."
The specific effects of maltreatment may depend on such factors as the age of the baby or child at the time of the abuse or neglect, whether the maltreatment was a one-time incident or prolonged occurrence, the identity of the abuser (e.g., parent or other adult), whether the child had a dependable nurturing individual in his or her life, the type and severity of the abuse, the intervention, and how long the maltreatment lasted. However, brief periods of moderate, predictable stress are not problematic; in fact, they prepare a child to learn and cope with the general world. The body's survival actually depends upon the ability to mount a response to stress (Shonkoff & Phillips, 2000).
Forming the Structure
The brain is made up of nerve cells also called neurons. At birth babies have almost all of the neurons more than 100 billion of them, although there is research that indicates some neurons are developed after birth and well into adulthood (Shonkoff & Phillips, 2000), the neurons babies have are primarily what they need to work with while growing up as children, adolescent, and adults.
Organizing the Structure
Brain development, is the process of generating, activating, strengthening, and discarding connections among the neurons; these connections are called synapses. Synapses, in the nervous system is a connection which allows a neuron to pass on information to other neurons, body muscles or glands.
It organizes the brain by forming neuronal pathways that connect the parts of the brain governing everything we do-from breathing and sleeping to thinking and feeling. The synapses present at birth are primarily those that govern our bodily functions such as heart rate, breathing, eating, and sleeping. Almost all other functions are developed as babies grow up into children and adults (Shore, 1997).
Daniel Siegel, medical director of the Infant and Preschool Service at the University of California, L.A., has found important links between interpersonal experiences and neurobiological development. There are clear links between neglect and abuse and later psychological, emotional, behavioral, and interpersonal disorders. The basis for this linkage is the impact that abuse and neglect have on brain development.
Generally the Left Hemisphere of the brain is the site of language, motor activity on the right side of the body, and logical thought based on language.
The Right Hemisphere of the brain is responsible for motor activity on the left side of the body, context perceptions, and holistic perception.
The Orbito-Frontal Cortex (the part of the brain directly behind the eyes) is responsible for integrating emotional responses generated in the limbic system with higher cognitive functions, such as planning and language, in the cerebral cortex’s prefrontal lobes.
The Left Orbito-Frontal Cortex is responsible for memory creation while the Right Orbito-Frontal Cortex is responsible for memory retrieval.
The Left and the Right Hemispheres of the Brain and its Processes
Healthy functioning requires an integrated right and left hemisphere. A substantial number of synaptic connections among brain cells develop during the first year of life. An integrated brain requires connections between the hemispheres by the Corpus Callosum.
Abused and neglected children have smaller Corpus Callosum than non-abused children. Abused and neglected children have poorly integrated cerebral hemispheres. This poor integration of hemispheres and underdevelopment of the Orbitofrontal Cortex is the basis for such symptoms as difficulty regulating emotion, lack of cause-effect thinking, inability to accurately recognize emotions in others, inability of the child to articulate the child’s own emotions, an incoherent sense of self and autobiographical history, and a lack of conscience.
Stressful experiences that are overtly traumatizing cause chronic elevated levels of neuroendocrine hormones. High levels of these hormones can cause permanent damage to the hippocampus, which is critical for memory. Based on this we can assume that psychological trauma can impair a person’s ability to create and retain memory and impede trauma resolution.
Abuse—Physical, Sexual, and Emotional
Abuse can refer to physical abuse, such as hitting, shaking, burning, or other forms of maltreatment that a parent or other caregiver might inflict. In the long-term, shaking can damage the fragile brain so that a child develops a range of sensory impairments, as well as cognitive, learning, and behavioral disabilities.
Emotional abuse generally refers to any ijury to a child's psychological or emotional stability (Child Welfare Information Gateway, 2008). Chronic stress may also qualify as emotional abuse. In some States, alcohol or substance abuse or domestic violence that affects the unborn child is considered child abuse. Physical abuse can cause direct damage to a baby's or child's developing brain. For instance, we now have extensive evidence of the damage that shaking a baby can cause.
According to the National Center on Shaken Baby Syndrome (2009), shaking can destroy brain tissue and tear blood vessels. In the short-term, shaking can lead to seizures, loss of consciousness, or even death.
Neglect—Lack of Stimulation
While chronic abuse and neglect can result in sensitized fear response patterns, neglect alone also can result in other problems. Malnutrition is a classic example of neglect. Malnutrition, both before and during the first few years after birth, can result in stunted brain growth and slower passage of electrical signals in the brain (Shonkoff & Phillips, 2000).
The most common form of malnutrition in the United States, iron deficiency, can affect the growing brain and result in cognitive and motor delays, anxiety, depression, social problems, and attention problems (Shonkoff & Phillips, 2000).
Although neglect often is thought of as a failure to meet a child's physical needs for food, shelter, and safety, neglect also can be a failure to meet a child's cognitive, emotional, or social needs. For example, babies need to experience face-to-face baby talk and hear countless repetitions of sounds in order to build the brain circuitry that will enable them to start making sounds and eventually say words. If babies' sounds are ignored repeatedly, their language may be delayed. These types of delays may extend to all types of normal development for neglected children, including their cognitive-behavioral, socio-emotional, and physical development (Scannapieco, 2008).
Global Neglect
Some specific long-term effects of abuse and neglect on the developing brain can include, (Teicher, 2000):
• Diminished growth in the left hemisphere, which may increase the risk for depression.
• Irritability in the limbic system, setting the stage for the emergence of panic disorder and posttraumatic stress disorder.
• Smaller growth in the hippocampus and limbic abnormalities, which can increase the risk for dissociative disorders and memory impairments
• Impairment in the connection between the two brain hemispheres, which has been linked to symptoms of attention-deficit/hyperactivity disorder.
Some causes of child abuse and neglect are:
• Today’s western, busy and career conscious lifestyle, single-parent and contemporary family societies.
- Both parents work either to meet the demands of their needs and wants or career is becomes more important than their children’s welfare.
- Parenting is considered old fashioned, low self-image and status in society. A parent does not have recognition or is thought not have a good future if one stays hone to look after their children till they start schooling. Contemporary families mostly do not have grandparents or other extended family members with them.
- Due to many similar reasons as stated above, children are sent to child care, nanny-care, and preschool. There are high chances that children left in these types of care, face neglect and in some cases even abuse.
• Unplanned/Teenage Pregnancy
- Inexperience in parenting, too young or not prepared for a child during that stage of their lives. Some parents or single moms are not willing to change their lifestyle and take up the responsibility; they also might not have support of their family or society.
• Domestic violence, poor relationship between parents, broken family
• Poverty, large family have lot of children to look after, lack of family planning , unemployment
We say that our children, the next generation are the future of our society, our country and the world. As adults, parents, family members/friends, guardian, teachers, it is our responsibility to ensure that children get the utmost care, love, attention, stable home environment, food and education to have a healthy and stable future, to become a mature, responsible adult.
How we mold these innocent and immature minds depend on their nurture, love and care they get from us. Educating adults, expecting parents, married couple, child - care takers and teachers on parenting and importance of child development and impact of abuse and neglect could be one of the solutions to reduce abuse and neglect on children. If an individual has gone through some abuse or neglect in their childhood they some say, their children might go through similar experiences but I say, why not learn from that past bad experience, put a stop to it by ensuring that their children doesn’t have to go through it.
Child care services can also play an important in reducing such occurrences by improving their services, ensuring that abused and neglected children get stable home environment and making adoption criteria more stringent. By the time child abuse and neglect are reported, most children have suffered to the extent that they start showing signs of it. Therefore to eliminate this problem parents and guardian need to learn and understand that their children’s safety and future lies in their hands.
References
http://www.childwelfare.gov/pubs/issue_briefs/brain_development/effects.cfm
http://teacher.scholastic.com/professional/bruceperry/abuse_neglect.htm
http://www.childwelfare.gov/can/impact/development/brain.cfm
Thursday, September 15, 2011
Mind-Altering Bugs
Mind-Altering Bugs
by Greg Miller on 29 August 2011,
Hundreds of species of bacteria call the human gut their home. This gut "microbiome" influences our physiology and health in ways that scientists are only beginning to understand. Now, a new study suggests that gut bacteria can even mess with the mind, altering brain chemistry and changing mood and behavior.
In recent years, researchers have become increasingly interested in how gut bacteria might influence the brain and behavior, says John Cryan, a neuroscientist at University College Cork in Ireland. So far, most of the work has focused on how pathogenic bugs influence the brain by releasing toxins or stimulating the immune system, Cryan says. One recent study suggested that even benign bacteria can alter the brain and behavior, but until now there has been very little work in this area, Cryan says.
To further investigate the mind-altering potential of benign bacteria, Cryan and colleagues at McMaster University in Canada fed mice a broth containing a benign bacterium, Lactobacillus rhamnosus. The scientists chose this particular bug partly because they had a handy supply and also because related Lactobacillus bacteria are a major ingredient of probiotic supplements and very little is known about their potential side effects, Cryan says.
In this case, the side effects appeared to be beneficial. Mice whose diets were supplemented with L. rhamnosus for 6 weeks exhibited fewer signs of stress and anxiety in standard lab tests, Cryan and colleagues report online today in the Proceedings of the National Academy of Sciences. For example, the rodents spent more time exploring narrow elevated walkways and wide-open spaces, which are scary to rodents, and they exhibited a smaller spike in stress hormone levels when the researchers put them in water. "This was really exciting because it tells us the animals are more chilled out and don't mount the same stress response," Cryan says.
In the brains of the treated mice, the researchers found changes in the activity of genes that encode portions of the receptor for the neurotransmiter GABA. GABA typically dampens neural activity, and many drugs for treating anxiety disorders target its receptors. The pattern of changes in the GABA receptors was complicated—more GABA receptors containing a certain component in some brain regions, for example, and fewer receptors with that component in other regions—but Cryan says they're consistent with an overall effect of reducing anxiety. None of these effects occurred in mice that ate a broth with no added bacteria.
The changes in GABA receptors and the antianxiety effects of L. rhamnosus disappeared when the researchers cut the vagus nerve before feeding the bacteria to mice. This nerve is a major conduit of sensory information from the gut to the brain, and this experiment shows it must be intact for L. rhamnosus to have an effect on the brain. The details of how the bacteria influence the brain through the vagus nerve still need to be elucidated, Cryan says. "That's what we have to figure out next."
"This is pioneering work," says Mark Lyte, a microbial endocrinologist at the Texas Tech University Health Sciences Center in Abilene. "It's really showing that you can alter emotional states by regulating the microbiome."
The findings "open up very exciting speculation" about using probiotics to treat mood disorders in people, says Emeran Mayer, a gastroenterologist at the University of California, Los Angeles. But Mayer says he's skeptical that the findings will translate easily from mice to people. "Personally, I think human emotional behavior is much more complex, so I don't think you'll ever find these kinds of dramatic responses." Lyte urges caution as well. "It MAY, in really big capitals, prove to be an adjunct to therapy, but there are a number of steps that need to be done."
by Greg Miller on 29 August 2011,
Hundreds of species of bacteria call the human gut their home. This gut "microbiome" influences our physiology and health in ways that scientists are only beginning to understand. Now, a new study suggests that gut bacteria can even mess with the mind, altering brain chemistry and changing mood and behavior.
In recent years, researchers have become increasingly interested in how gut bacteria might influence the brain and behavior, says John Cryan, a neuroscientist at University College Cork in Ireland. So far, most of the work has focused on how pathogenic bugs influence the brain by releasing toxins or stimulating the immune system, Cryan says. One recent study suggested that even benign bacteria can alter the brain and behavior, but until now there has been very little work in this area, Cryan says.
To further investigate the mind-altering potential of benign bacteria, Cryan and colleagues at McMaster University in Canada fed mice a broth containing a benign bacterium, Lactobacillus rhamnosus. The scientists chose this particular bug partly because they had a handy supply and also because related Lactobacillus bacteria are a major ingredient of probiotic supplements and very little is known about their potential side effects, Cryan says.
In this case, the side effects appeared to be beneficial. Mice whose diets were supplemented with L. rhamnosus for 6 weeks exhibited fewer signs of stress and anxiety in standard lab tests, Cryan and colleagues report online today in the Proceedings of the National Academy of Sciences. For example, the rodents spent more time exploring narrow elevated walkways and wide-open spaces, which are scary to rodents, and they exhibited a smaller spike in stress hormone levels when the researchers put them in water. "This was really exciting because it tells us the animals are more chilled out and don't mount the same stress response," Cryan says.
In the brains of the treated mice, the researchers found changes in the activity of genes that encode portions of the receptor for the neurotransmiter GABA. GABA typically dampens neural activity, and many drugs for treating anxiety disorders target its receptors. The pattern of changes in the GABA receptors was complicated—more GABA receptors containing a certain component in some brain regions, for example, and fewer receptors with that component in other regions—but Cryan says they're consistent with an overall effect of reducing anxiety. None of these effects occurred in mice that ate a broth with no added bacteria.
The changes in GABA receptors and the antianxiety effects of L. rhamnosus disappeared when the researchers cut the vagus nerve before feeding the bacteria to mice. This nerve is a major conduit of sensory information from the gut to the brain, and this experiment shows it must be intact for L. rhamnosus to have an effect on the brain. The details of how the bacteria influence the brain through the vagus nerve still need to be elucidated, Cryan says. "That's what we have to figure out next."
"This is pioneering work," says Mark Lyte, a microbial endocrinologist at the Texas Tech University Health Sciences Center in Abilene. "It's really showing that you can alter emotional states by regulating the microbiome."
The findings "open up very exciting speculation" about using probiotics to treat mood disorders in people, says Emeran Mayer, a gastroenterologist at the University of California, Los Angeles. But Mayer says he's skeptical that the findings will translate easily from mice to people. "Personally, I think human emotional behavior is much more complex, so I don't think you'll ever find these kinds of dramatic responses." Lyte urges caution as well. "It MAY, in really big capitals, prove to be an adjunct to therapy, but there are a number of steps that need to be done."
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