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Genetic Code of Common Cold Cracked
Genetic Code of Common Cold Cracked
99 rhinoviruses now sequenced, could lead to new treatments, researchers say
Today's medical breakthrough: a cure for the common cold.
Well, researchers are reporting what could at least be a significant step in that direction: the genetic codes of the 99 known viruses responsible for those pesky nasal infections.
"There has been brilliant work done trying to synthesize compounds against the common cold," said Dr. Stephen B. Liggett, director of the cardiopulmonary genomics program at the University of Maryland, and senior author of a report on the discoveries published in the Feb. 12 online issue of Science. "But we have not been working with a full knowledge of the genetics of rhinoviruses. Now that we have the full complement of known ones, we see there are subfamilies of rhinoviruses clustering together. The hope is that there could be a drug for each subfamily."
Liggett and the other researchers in the project used virus samples collected by nasal swabs in doctors' offices over two decades and sent to the American Type Culture Collection, a private nonprofit organization headquartered in Virginia. Some rhinovirus genomes had already been sequenced from those samples. The current study adds 80 new full genome sequences, showing their relationships.
"We made a family tree," Liggett said. "The major branches are going to be fixed. We have sequenced rhinoviruses from 10,000 individuals at different locations in the United States, and we see major branches in the trees, with lots of little twigs in the tree."
The viruses are still evolving, Liggett said. "We compared some samples taken in 2005 with some from the 1970s, and found a fair number of mutations," he said. "But the major evolutionary structure of the tree is not going to change."
Rhinoviruses can't change too much, Liggett explained. "If they mutate to become super virulent, they destroy the cells they live in. They might become less deadly and narrow down the window they operate in. We don't understand that window very well."
There is hope that a careful study of the viral genomes will reveal one central point of attack that could be exploited by drug makers. "What we would like is a single Achilles' heel for all the viruses that we have found so far, and we could attack in that direction," Liggett said.
But the viruses are found to have impressive powers of change. The study shows that some human rhinoviruses result from the exchange of genetic material from two separate strains infecting the same person. Such recombination had not been thought possible for rhinoviruses.
That recombination is one reason why a vaccine against the common cold appears to be impossible, said Ann C. Palmenberg, director of the Institute for Molecular Virology at the University of Wisconsin, and lead author of the sequencing effort. The viruses just keep changing too much.
A second reason is that the rhinoviruses do their dirty work on the mucosa, the outer lining of the inner nose, Palmenberg said. "We're not good at making vaccines that give mucosal protection," she said.
But there is hope for a single drug that would be effective against many rhinoviruses, Palmenberg and Liggett agreed. "Drugs have the probability of taking out multiple serotypes at one time," Palmenberg said.
Who would develop such a drug? "The most likely scenario is that a small biotechnology company would begin the work, and as they made progress, they would get the attention of a larger drug company," Liggett said. "Occasionally, a biotechnology can keep the ball rolling all the way through. It will be interesting to see how this unfolds."
More information
Detailed information on the common cold and the viruses that cause it is available from the U.S. National Institute of Allergy and Infectious Diseases.
SOURCES: Stephen B. Liggett, M.D., director, cardiopulmonary genomics program, and professor, medicine and physiology, University of Maryland, Baltimore; Ann C. Palmenberg, Ph.D., director, Institute for Molecular Virology, and professor, biochemistry, University of Wisconsin, Madison; Feb. 12, 2009, Science, online
99 rhinoviruses now sequenced, could lead to new treatments, researchers say
Today's medical breakthrough: a cure for the common cold.
Well, researchers are reporting what could at least be a significant step in that direction: the genetic codes of the 99 known viruses responsible for those pesky nasal infections.
"There has been brilliant work done trying to synthesize compounds against the common cold," said Dr. Stephen B. Liggett, director of the cardiopulmonary genomics program at the University of Maryland, and senior author of a report on the discoveries published in the Feb. 12 online issue of Science. "But we have not been working with a full knowledge of the genetics of rhinoviruses. Now that we have the full complement of known ones, we see there are subfamilies of rhinoviruses clustering together. The hope is that there could be a drug for each subfamily."
Liggett and the other researchers in the project used virus samples collected by nasal swabs in doctors' offices over two decades and sent to the American Type Culture Collection, a private nonprofit organization headquartered in Virginia. Some rhinovirus genomes had already been sequenced from those samples. The current study adds 80 new full genome sequences, showing their relationships.
"We made a family tree," Liggett said. "The major branches are going to be fixed. We have sequenced rhinoviruses from 10,000 individuals at different locations in the United States, and we see major branches in the trees, with lots of little twigs in the tree."
The viruses are still evolving, Liggett said. "We compared some samples taken in 2005 with some from the 1970s, and found a fair number of mutations," he said. "But the major evolutionary structure of the tree is not going to change."
Rhinoviruses can't change too much, Liggett explained. "If they mutate to become super virulent, they destroy the cells they live in. They might become less deadly and narrow down the window they operate in. We don't understand that window very well."
There is hope that a careful study of the viral genomes will reveal one central point of attack that could be exploited by drug makers. "What we would like is a single Achilles' heel for all the viruses that we have found so far, and we could attack in that direction," Liggett said.
But the viruses are found to have impressive powers of change. The study shows that some human rhinoviruses result from the exchange of genetic material from two separate strains infecting the same person. Such recombination had not been thought possible for rhinoviruses.
That recombination is one reason why a vaccine against the common cold appears to be impossible, said Ann C. Palmenberg, director of the Institute for Molecular Virology at the University of Wisconsin, and lead author of the sequencing effort. The viruses just keep changing too much.
A second reason is that the rhinoviruses do their dirty work on the mucosa, the outer lining of the inner nose, Palmenberg said. "We're not good at making vaccines that give mucosal protection," she said.
But there is hope for a single drug that would be effective against many rhinoviruses, Palmenberg and Liggett agreed. "Drugs have the probability of taking out multiple serotypes at one time," Palmenberg said.
Who would develop such a drug? "The most likely scenario is that a small biotechnology company would begin the work, and as they made progress, they would get the attention of a larger drug company," Liggett said. "Occasionally, a biotechnology can keep the ball rolling all the way through. It will be interesting to see how this unfolds."
More information
Detailed information on the common cold and the viruses that cause it is available from the U.S. National Institute of Allergy and Infectious Diseases.
SOURCES: Stephen B. Liggett, M.D., director, cardiopulmonary genomics program, and professor, medicine and physiology, University of Maryland, Baltimore; Ann C. Palmenberg, Ph.D., director, Institute for Molecular Virology, and professor, biochemistry, University of Wisconsin, Madison; Feb. 12, 2009, Science, online
Echinacea Supplements that failed
Herb Pharm Super Echinacea (1 to 2 vegetarian caps No specific claimed amount
E. purpurean dried root and seed powder; dried juice extract of root, leaf, flower
ImmuGo (1 liquid-filled vial, up to 3 per day) No specific claimed amount; extract listed within a proprietary blend E. purpurea root
Planetary Herbals Full Spectrum Echinacea (liquid, 1.6 mL [70 drops], 3 per day)
No specific claimed amount of extract
Extract of E. angustifolia or E. pallida root, E. purpurea seed, root, leaf
Herbs for Kids Sweet Echinacea (liquid, 1 mL, 3 to 12 per day)
No specific claimed amount; extract listed within a proprietary blend E. purpurea root
ConsumerTips for Buying and Using:
Buying Echinacea:
Consumers should expect the following information on echinacea product labels and all of this information is required by the FDA (although not all products comply):
* The species of echinacea (i.e., E. purpurea, E. angustifolia, or E. pallida);
* The part of the plant used, such as root or the aerial (above-ground) portions which include the stem, leaves, and flowers;"
* The form of echinacea used (e.g., whole herb or root, extract, or tincture);
* The amount of echinacea per pill or dose in grams (g) or milligrams (mg) [1 gram = 1,000 milligrams] (May not be provided for proprietary blends but preferable if it is.)
Some newer products are standardized to specific substances such as cichoric acid, alkamides, and polysaccharides. The concentration of total phenols may also be indicated on the labels of echinacea products. The total phenolic content (determined by HPLC) should be at least 1% for quality whole herb or root products and proportionally higher for extracts and tinctures depending on their concentration.
Almost all the clinical studies showing benefit have been conducted with products extracted from the aerial (i.e., stems, leaves, flowers) portions of E. purpurea, either as pressed juice extracts or alcohol extracts often dried into extract powders (900 mg per day) . An extract of the root portion of E. pallida (900 mg per day) has also showed some promise in reducing the average length of a cold, although it is not widely used . The United States Pharmacopeia and WHO additionally recognize the use of the root from E. purpurea and E. angustifolia. A liquid extract of E. angustifolia root was shown to help in the prevention of upper respiratory tract infections
Because echinacea products come in many forms and concentrations, the dosage will vary considerably depending on the product. While at first glance it may seem that products made with a large amount of dried herb powder (sometimes over 3,000 mg per day) are giving you "more" echinacea than extracts (typically several hundred milligrams per day), keep in mind that extracts are generally 4 times the concentration of powders depending on the type of extract. While some herbalists believe that dried herb powders are superior to extracts because they provide a wider spectrum of plant chemicals, there is less clinical evidence for dried herb powders of echinacea than for extracts.
Some echinacea products may also contain the herb goldenseal. While goldenseal may be useful as an antibacterial agent when applied directly on topical infections, clinical studies have not shown it to be useful in treating colds since it is not antiviral and it is specifically not to be used by pregnant women.
Elderberry is also an ingredient in some supplements that contain echinacea. Experimental pharmacological studies and a small number of clinical trials suggest that a standardized syrup made from elderberry fruit has an immune-enhancing effect which can help reduce infection from colds and flus. The usual dose for the clinically-tested standardized elderberry syrup ranges from 1 teaspoon four times daily for children to 2 teaspoons four times daily for adults for intensive use; regular daily prophylactic maintenance is 1 teaspoon daily for children and 2 teaspoons for daily for adults. A standardized extract of elderberry taken in four doses of 175 mg has recently shown possible efficacy in preventing flu symptoms in a small pilot trial
No meaningful scientific studies have evaluated the combination of echinacea with goldenseal or elderberry. However, there have been numerous positive studies of products that contain fixed combinations of echinacea plus thuja (white cedar, Thuja occidentalis) and baptisia (wild indigo, Baptisia tinctoria), and other combinations of echinacea preparations with propolis and vitamin C, or with the extract of the leaf of the immune-modulating herb Andrographis paniculata.
Herb Pharm Super Echinacea (1 to 2 vegetarian caps No specific claimed amount
E. purpurean dried root and seed powder; dried juice extract of root, leaf, flower
ImmuGo (1 liquid-filled vial, up to 3 per day) No specific claimed amount; extract listed within a proprietary blend E. purpurea root
Planetary Herbals Full Spectrum Echinacea (liquid, 1.6 mL [70 drops], 3 per day)
No specific claimed amount of extract
Extract of E. angustifolia or E. pallida root, E. purpurea seed, root, leaf
Herbs for Kids Sweet Echinacea (liquid, 1 mL, 3 to 12 per day)
No specific claimed amount; extract listed within a proprietary blend E. purpurea root
ConsumerTips for Buying and Using:
Buying Echinacea:
Consumers should expect the following information on echinacea product labels and all of this information is required by the FDA (although not all products comply):
* The species of echinacea (i.e., E. purpurea, E. angustifolia, or E. pallida);
* The part of the plant used, such as root or the aerial (above-ground) portions which include the stem, leaves, and flowers;"
* The form of echinacea used (e.g., whole herb or root, extract, or tincture);
* The amount of echinacea per pill or dose in grams (g) or milligrams (mg) [1 gram = 1,000 milligrams] (May not be provided for proprietary blends but preferable if it is.)
Some newer products are standardized to specific substances such as cichoric acid, alkamides, and polysaccharides. The concentration of total phenols may also be indicated on the labels of echinacea products. The total phenolic content (determined by HPLC) should be at least 1% for quality whole herb or root products and proportionally higher for extracts and tinctures depending on their concentration.
Almost all the clinical studies showing benefit have been conducted with products extracted from the aerial (i.e., stems, leaves, flowers) portions of E. purpurea, either as pressed juice extracts or alcohol extracts often dried into extract powders (900 mg per day) . An extract of the root portion of E. pallida (900 mg per day) has also showed some promise in reducing the average length of a cold, although it is not widely used . The United States Pharmacopeia and WHO additionally recognize the use of the root from E. purpurea and E. angustifolia. A liquid extract of E. angustifolia root was shown to help in the prevention of upper respiratory tract infections
Because echinacea products come in many forms and concentrations, the dosage will vary considerably depending on the product. While at first glance it may seem that products made with a large amount of dried herb powder (sometimes over 3,000 mg per day) are giving you "more" echinacea than extracts (typically several hundred milligrams per day), keep in mind that extracts are generally 4 times the concentration of powders depending on the type of extract. While some herbalists believe that dried herb powders are superior to extracts because they provide a wider spectrum of plant chemicals, there is less clinical evidence for dried herb powders of echinacea than for extracts.
Some echinacea products may also contain the herb goldenseal. While goldenseal may be useful as an antibacterial agent when applied directly on topical infections, clinical studies have not shown it to be useful in treating colds since it is not antiviral and it is specifically not to be used by pregnant women.
Elderberry is also an ingredient in some supplements that contain echinacea. Experimental pharmacological studies and a small number of clinical trials suggest that a standardized syrup made from elderberry fruit has an immune-enhancing effect which can help reduce infection from colds and flus. The usual dose for the clinically-tested standardized elderberry syrup ranges from 1 teaspoon four times daily for children to 2 teaspoons four times daily for adults for intensive use; regular daily prophylactic maintenance is 1 teaspoon daily for children and 2 teaspoons for daily for adults. A standardized extract of elderberry taken in four doses of 175 mg has recently shown possible efficacy in preventing flu symptoms in a small pilot trial
No meaningful scientific studies have evaluated the combination of echinacea with goldenseal or elderberry. However, there have been numerous positive studies of products that contain fixed combinations of echinacea plus thuja (white cedar, Thuja occidentalis) and baptisia (wild indigo, Baptisia tinctoria), and other combinations of echinacea preparations with propolis and vitamin C, or with the extract of the leaf of the immune-modulating herb Andrographis paniculata.
I understand the right to life! but I'm all for stem cell. The research should help to find many cures!!
Great news , we are sure in interesting times one way and another, what do you think about the Stem cell research ,the President has lifted the ban , the implications seem huge and a lot of controversy along with it.
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