Herpes Medication Does Not Reduce Risk Of HIV Infection In Individuals With HSV-2, Study Finds

Daily Science Journal (Feb. 10, 2008) — An international clinical trial has found that acyclovir, a common medication for treating herpes simplex virus-2 (HSV-2), the most common cause of genital herpes, does not reduce the risk of HIV infection when taken by people infected with HSV-2. Multiple studies have shown that people with HSV-2 have a higher risk of acquiring HIV. Researchers had hoped that acyclovir's ability to suppress the herpes virus, and its associated genital sores and breaks in the skin, could cut down on the likelihood of HIV being transmitted to a person with HSV-2 during sexual intercourse.

The Phase III clinical trial was led by the University of Washington in Seattle, in coordination with the HIV Prevention Trials Network, an international consortium funded by the National Institute of Allergy and Infectious Diseases (NIAID) in the National Institutes of Health. The findings were presented this week at the Conference on Retroviruses and Opportunistic Infections in Boston.

"The study was successful in answering the question of whether acyclovir could cut down on the risk of HIV acquisition for people infected with HSV-2," explained Dr. Connie Celum, the leader of the study and a UW professor of global health and medicine in the Division of Allergy and Infectious Disease and director of the International Clinical Research Center in the UW Department of Global Health. "We were hopeful that acyclovir would help reduce HIV acquisition in people with HSV-2. Though the study did not find that acyclovir helped with HIV acquisition, we did find that it reduced genital ulcers associated with HSV-2. Now we need to continue our research on the mechanisms through which HSV-2 acts as a risk factor for HIV, and how we might be able to use that knowledge to reduce the spread of HIV."

HSV-2 is one of the most common sexually transmitted infections worldwide and is especially prevalent in areas with high rates of HIV infection. Most people who are infected with HSV-2 do not know they have the virus because symptoms can be mild or absent. In some infected individuals, the virus can produce recurring genital herpes, a condition characterized by sores and breaks in the skin of the genital region. An active HSV-2 infection also attracts immune-system cells called CD-4 T-cells to the genital region, and HIV easily attaches to this type of cell. Multiple studies have shown that people with HSV-2 have a two-fold increase in their risk of acquiring HIV.

This study followed up on those results to test the theory that suppressing HSV-2 could cut down on HIV acquisition. It was launched in 2003, and with nine study sites in Peru, South Africa, Zambia, Zimbabwe, and the United States, it was the largest study yet of herpes suppression. There were 3,277 people with HSV-2 initially enrolled in the study, 105 people excluded, and 3,172 people included in the final analysis. Volunteers in Peru and the United States were HSV-2-infected men who have sex with men, and volunteers in Africa were HSV-2-infected women.

Half of the participants were randomly assigned to receive either a placebo or a standard daily dose of acyclovir, 400 mg twice a day. The study was double-blinded, meaning that neither participants nor care providers knew which treatment the participants were receiving. Both the placebo and treatment groups received standard HIV-prevention treatment, which includes being supplied with condoms and given extensive counseling on how to reduce the risk of HIV infection.

Researchers found that there was a 3.9 percent HIV incidence rate, a total of 75 cases, in participants who received acyclovir suppression, and a 3.3 percent HIV incidence rate, or 64 cases, in the placebo group. The difference between the groups was not statistically significant. The acyclovir treatment did succeed in reducing genital ulcers -- participants in the treatment group had a 37 percent reduction in genital ulcer incidence, and a significantly lower proportion of ulcers due to HSV-2.

"The study answered the scientific questions it was designed to answer," says Dr. Anna Wald, a UW professor of medicine and epidemiology who also helped lead the study. "The sites were able to recruit and retain a large number of volunteers, who maintained a high level of adherence to the twice-daily drug regimen. While we are disappointed with the results, the study was well-conducted and provides a clear answer about using acyclovir to reduce the risk of becoming HIV-infected."

The study participants have been informed of the findings and are being counseled on the continued need to avoid HIV exposure. Volunteers who became infected with HIV during the trial have been referred for appropriate medical care and treatment.

The study was supported by NIAID, and the acyclovir was supplied by GlaxoSmithKline. The HIV Prevention Trials Network is led by Family Health International, the network laboratory of Johns Hopkins University, and the Statistical Center for HIV/AIDS Research and Prevention at the Fred Hutchinson Cancer Research Center in Seattle. The study was conducted at the following sites: Iquitos, Lima and Pucallpa, in Peru; Johannesburg, South Africa; New York, San Francisco, and Seattle, in the United States; Lusaka, Zambia; and Harare, Zimbabwe.

Adapted from materials provided by University Of Washington.

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Giving Mice A Cold Virus Offers Hope Of New Asthma Treatments

Daily Science Journal (Feb. 8, 2008) — Scientists have been able to recreate rhinovirus infection, which is behind most common colds, in a small animal for the first time. For fifty years since they were discovered, it had been thought that rhinoviruses could only infect humans and chimpanzees. But now a team of scientists led by Professor Sebastian Johnston at the MRC/Asthma UK Centre in Allergic Mechanisms of Asthma at Imperial College London, has been able to infect mice with rhinoviruses.

Scientists have been able to recreate rhinovirus infection, which is behind most common colds, in a small animal for the first time. For fifty years since they were discovered, it had been thought that rhinoviruses could only infect humans and chimpanzees. (Credit: iStockphoto/Jennifer Sheets)

Rhinoviruses are an unwelcome inconvenience for the majority of the population as they cause around three quarters of common colds. However they can also have serious consequences. In susceptible people, they can be fatal. They can lead to the hospitalisation of infants, pneumonia in people with weakened immune systems and they trigger most asthma attacks. They are also the major cause of acute attacks of COPD (chronic bronchitis and emphysema), and are thus the major killer in these diseases.

Professor Johnston said: “Until now it has not been possible to study rhinovirus infection in small animals. This has been a major obstacle to developing new treatments and there is currently no effective treatment for rhinovirus infection.”

It had been thought that mice and other small animals were resistant to rhinoviruses. Of the 100 known strains of rhinovirus, 90 per cent use a binding molecule, called ICAM-1 that is found on the surface of human cells, as their receptor. But the viruses are unable to bind to the mouse version of this receptor.

Professor Johnston explained: "We previously found that once inside the mouse cell a rhinovirus reproduces itself as well as it does in human cells. But the virus couldn’t infect the mouse cell because the receptor (acting like a door key) couldn’t get into the cell.

“Now we’ve modified the mouse receptor so it is more like a human one. This means the virus can infect the cells of these modified mice.”

Professor Johnston added: "We found that mice with the modified receptor were susceptible to infection with a rhinovirus. If combined with an allergen (ovalbumin which is found in egg white) that could cause an allergic reaction in the lungs, the virus could make the response worse and lead to an 'asthma attack'."

The team was able to observe that when the virus was combined with an allergic reaction, the mouse responded similarly to humans. This means it provides a good model for the study of severe asthma attacks.

"These mouse models should provide a major boost to research efforts to develop new treatments for the common cold, as well as for more potentially fatal illnesses such as acute attacks of asthma and of COPD."

The chief executive of the Medical Research Council, Sir Leszek Borysiewicz said: “This important and fundamental discovery will enable us to understand the effects rhinoviruses and common colds have on our health. It will open up new paths to finding treatments which have been delayed for many years and provides us with the opportunities for further breakthroughs in the future.”

Leanne Male, Assistant Director of Research at Asthma UK commented: "Ninety per cent of people with asthma tell us that colds and flu triggers their asthma symptoms but as yet there is no specific treatment for virally induced asthma attacks and steroid treatments are only partially effective against them. We welcome this latest advancement as it will lead to a greater understanding of viral infections and their link with asthma and may help the development of a suitable treatment for virus-induced asthma attacks, thus greatly improving the lives of the 5.2 million people with the condition in the UK."

Journal article: Mouse models of rhinovirus-induced disease and exacerbation of allergic airway inflammation. Published online in Nature Medicine.

The research was funded by the Medical Research Council, Asthma UK and GlaxoSmithKline.

Adapted from materials provided by Imperial College London.

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You Are What You Eat: Some Differences Between Humans And Chimpanzees Traced To Diet

Daily Science Journal (Jan. 30, 2008) — Using mice as models, researchers at the Max Planck Institute for Evolutionary Anthropology traced some of the differences between humans and chimpanzees to differences in our diet.

Humans consume a distinct diet compared to other apes, like this chimpanzee eating an apple. Not only do we consume much more meat and fat, but we also cook our food. It has been hypothesized that adopting these dietary patterns played a key role during human evolution. (Credit: iStockphoto/Stephanie Swartz)

Humans consume a distinct diet compared to other apes. Not only do we consume much more meat and fat, but we also cook our food. It has been hypothesized that adopting these dietary patterns played a key role during human evolution. However, to date, the influence of diet on the physiological and genetic differences between humans and other apes has not been widely examined.

By feeding laboratory mice different human and chimp diets over a mere two week period, researchers at the Max-Planck-Institute for Evolutionary Anthropology in Leipzig, Germany, were able to reconstruct some of the physiological and genetic differences observed between humans and chimpanzees.

The researchers fed laboratory mice one of three diets: a raw fruit and vegetable diet fed to chimpanzees in zoos, a human diet consisting of food served at the Institute cafeteria or a pure fast food menu from the local McDonald's™ (the latter caused the mice to significantly gain weight). The chimpanzee diet was clearly distinct from the two human diets in its effect on the liver - thousands of differences were observed in the levels at which genes were expressed in the mouse livers. No such differences were observed in the mouse brains. A significant fraction of the genes that changed in the mouse livers, had previously been observed as different between humans and chimpanzees. This indicates that the differences observed in these particular genes might be caused by the difference in human and chimpanzee diets.

Furthermore, the diet-related genes also appear to have evolved faster than other genes - protein and promoter sequences of these genes changed faster than expected, possibly because of adaptation to new diets.

Citation: Somel M, Creely H, Franz H, Mueller U, Lachmann M, et al (2008) Human and Chimpanzee Gene Expression Differences Replicated in Mice Fed Different Diets. PLoS One 3(1): e1504. doi:10.1371/journal.pone.0001504 http://www.plosone.org/doi/pone.0001504

Adapted from materials provided by Public Library of Science, via EurekAlert!, a service of AAAS.

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Green Tea May Protect Bladder From Becoming Inflamed

Daily Science Journal (Jan 21, 2007) — Herbal agents could be used to treat inflammatory bladder diseases, according to a preliminary study that looked at the ability of green tea to protect bladder cells from inflammation. The University of Pittsburgh School of Medicine study, being presented at the annual meeting of the American Urological Association (AUA) in Anaheim, Calif., found that components of green tea protected bladder cells from damage in culture.

Green tea, reported to have many health benefits, is rich in powerful antioxidants that make it a possible remedy for many medical conditions. It is comprised of catechins -- plant metabolites that provide it with many anti-oxidative properties.

"We discovered that catechins found in green tea protected both normal and cancerous bladder cells from inflammation when we exposed the cells to hydrogen peroxide," said Michael B. Chancellor, M.D., professor of urology and gynecology at the University of Pittsburgh School of Medicine. "Although further studies are needed, these results indicate herbal supplements from green tea could be a treatment option for various bladder conditions that are caused by injury or inflammation."

In the study, normal and cancerous bladder cells were exposed to two major catechin components of green tea, epigallocatechin gallate (EGCG) and epicatechin gallate (ECG), for 23 hours. Both significantly protected cell lines from exposure to hydrogen peroxide, which damages or kills cells. The concentrations of EGCG and ECG used in the study were at levels that may be achieved through dietary intake.

Approximately ten million American adults have problems controlling their bladders. Bladder disease affects both men and women and can include incontinence or interstitial cystitis, a chronic inflammatory condition that causes frequent, urgent and painful urination and pelvic discomfort.

Co-investigators of the study include Shelby Morrisroe, M.D., Christian Coyle, Ph.D., Brian Phillips, Ph.D., William de Groat, Ph.D., and Naoki Yoshimura, M.D., Ph.D., all with the University of Pittsburgh School of Medicine. The study is Abstract 299 in the AUA proceedings.

The study is funded by the Fishbein Family CURE-IC Program.

Adapted from materials provided by University of Pittsburgh Schools of the Health Sciences, via EurekAlert!, a service of AAAS.

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Turning Anthrax Toxin Into A Cancer Killer

Daily Science Journal (Jan. 5, 2008) — Most people wouldn't consider anthrax toxin to be beneficial, but this bacterial poison may someday be an effective cancer therapy. Anthrax toxin has actually been shown to be fairly selective in targeting melanoma cells, although the risk of non-cancer toxicity prevents any clinical use.

After binding to cell surface markers, the MMP-activated PA protein (PA-L1) is cleaved by surface associated MMPs, releasing the PA20 fragment. The remaining receptor-bound fragment rapidly oligomerizes to form a heptamer. Up to three molecules of anthrax lethal factor (LF) bind to the heptamer, which is then internalized. Once inside the cell, the complex encounters an acidic environment, which induces a conformational change and allows the LF to enter the cytosol. LF released into the cytosol shuts down multiple signaling pathways, leading to inhibition of tumor angiogenesis and human melanoma cell death. (Credit: Image created by Drs. Shihui Liu, Mahtab Moayeri, and Stephen H. Leppla)

To develop a better and safer treatment, Stephen Leppla and colleagues created a mutated antrax toxin that could only be turned on by matrix metalloproteinases (MMP), proteins that are overproduced only in cancer cells.

When they tested this mutated toxin in mice, the researchers observed that 100% of the animals tolerated a dose that would be lethal for the natural toxin. The MMP-toxin was also better at killing melanoma tumors than natural toxin, due to its higher specificity and longer half-life in the blood.

Even better, Leppla and colleagues saw that MMP-toxin was not limited to melanoma, and could also kill other tumors like colon and lung. This more widespread activity was due to the toxin's ability to inhibit angiogenesis, or the formation of new blood vessels.

These encouraging mouse results suggest that modified anthrax toxin could be clinically viable, and this potent killer might someday be put to good use.

Adapted from materials provided by American Society for Biochemistry and Molecular Biology, via EurekAlert!, a service of AAAS.

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Flavonoid-rich Diet Helps Women Decrease Risk Of Ovarian Cancer

Daily Science Journal (Nov. 20, 2007) — New research out of the Channing Laboratory at Brigham and Women’s Hospital (BWH) reports that frequent consumption of foods containing the flavonoid kaempferol, including nonherbal tea and broccoli, was associated with a reduced risk of ovarian cancer. The researchers also found a decreased risk in women who consumed large amounts of the flavonoid luteolin, which is found in foods such as carrots, peppers, and cabbage.

Broccoli and carrots are among the foods that are high in flavinoids. (Credit: iStockphoto/Albert Lozano)

“This is good news because there are few lifestyle factors known to reduce a woman’s risk of ovarian cancer,” said first author Margaret Gates, a research fellow at BWH. “Although additional research is needed, these findings suggest that consuming a diet rich in flavonoids may be protective.”

The causes of ovarian cancer are not well understood. What is known is that the earlier the disease is found and treated, the better the chance for recovery; however, the majority of cases are diagnosed at an advanced (metastasized) stage after the cancer has spread beyond the ovaries. According to the National Cancer Institute, the five-year relative survival rate for women diagnosed with localized ovarian cancer is 92.4 percent. Unfortunately, this number drops to 29.8 percent if the cancer has already metastasized.

In this first prospective study to look at the association between these flavonoids and ovarian cancer risk, Gates and colleagues calculated intake of the flavonoids myricetin, kaempferol, quercetin, luteolin, and apigenin among 66,940 women enrolled in the Nurses’ Health Study. In this population, 347 cases of epithelial ovarian cancer were diagnosed between 1984 and 2002.

Although total intake of these five common dietary flavonoids was not clearly beneficial, the researchers found a 40 percent reduction in ovarian cancer risk among the women with the highest kaempferol intake, compared with women with the lowest intake. They also found a 34 percent reduction in the risk of ovarian cancer among women with the highest intake of luteolin, compared with women with the lowest intake.

“In this population of women, consumption of nonherbal tea and broccoli provided the best defense against ovarian cancer,” concluded Gates, who is also a research fellow at the Harvard School of Public Health. “Other flavonoid-rich foods, such as onions, beans, and kale, may also decrease ovarian cancer risk, but the number of women who frequently consumed these foods was not large enough to clearly evaluate these associations. More research is needed.”

These findings appear in the Nov. 15, 2007, issue of the International Journal of Cancer.

Adapted from materials provided by Harvard University.

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Consumption Of Green Tea Associated With Reduced Mortality In Japanese Adults, Drinking Tea Associated With Lower Risk Of Ovarian Cancer

Daily Science Journal (Sep. 13, 2007) — Adults in Japan who consumed higher amounts of green tea had a lower risk of death due to all causes and due to cardiovascular disease, according to a study in the September 13 issue of JAMA. But there was no link between green tea consumption and a reduced risk of death due to cancer.

Tea is the most consumed beverage in the world aside from water. Three billion kilograms of tea are produced each year worldwide, according to background information in the article. Because of the high rates of tea consumption in the global population, even small effects in humans could have large implications for public health. Among teas, green tea polyphenols have been extensively studied as cardiovascular disease (CVD) and cancer chemopreventive agents. Although substantial evidence from in vitro and animal studies indicates that green tea preparations may impede CVD and carcinogenic processes, the possible protective role of green tea consumption against these diseases in humans remains unclear.

Shinichi Kuriyama, M.D., Ph.D., of the Tohoku University School of Public Policy, Sendai, Japan, and colleagues examined the association between green tea consumption and mortality (death rate) due to all causes, CVD, and cancer within a large population. The study, initiated in 1994, included 40,530 adults (age 40 to 79 years) in northeastern Japan, where green tea is widely consumed. Within this region, 80 percent of the population drinks green tea and more than half of them consume 3 or more cups and day. The participants, who had no history of stroke, coronary heart disease, or cancer at baseline, were followed for up to 11 years (1995-2005) for all-cause death and for up to 7 years (1995-2001) for cause-specific death.

Over 11 years of follow-up, 4,209 participants died, and over 7 years of follow-up, 892 participants died of cardiovascular disease and 1,134 participants died of cancer. The researchers found that green tea consumption was inversely associated with death due to all causes and due to cardiovascular disease. Compared with participants who consumed less than 1 cup/d of green tea, those who consumed 5 or more cups/d had a risk of all-cause mortality and CVD mortality that was 16 percent lower (during 11 years of follow-up) and 26 percent lower (during 7 years of follow-up), respectively.

These inverse associations of all-cause and CVD mortality were stronger among women, although the inverse association for green tea consumption was observed in both sexes. In women, compared with those who consumed less than 1 cup/d of green tea, those who consumed 5 or more cups/d had a 31 percent lower risk of CVD death.

The researchers found there no significant association between green tea consumption and death from cancer. There were weak or neutral relationships between black tea or oolong tea and mortality.

"Clinical trials are ultimately necessary to confirm the protective effect of green tea on mortality," the authors write.

This study was supported by a Health Sciences Research Grant for Health Services, Ministry of Health, Labour, and Welfare, Japan.

Adapted from materials provided by JAMA and Archives Journals, via EurekAlert!, a service of AAAS.

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Drinking Tea Associated With Lower Risk Of Ovarian Cancer

Women who drank at least two cups of tea a day had a lower risk of ovarian cancer than those who did not drink tea, according to a study in the December 12/26 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.

Evidence from laboratory studies indicates that green and black tea preparations may protect against various cancers. But few epidemiological studies have examined the relationship specifically between tea consumption and the risk of ovarian cancer, according to background information in the article.

Susanna C. Larsson, M.Sc., and Alicja Wolk, D.M.Sc., of the National Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden, prospectively examined the association between tea consumption and the risk of ovarian cancer in 61,057 women, aged 40 to 76, who were participants in the population-based Swedish Mammography Cohort. Participants completed a validated 67-item food frequency questionnaire at enrollment between 1987 and 1990, and were followed for cancer incidence through December 2004. At baseline, 68 percent of the participants reported drinking tea (mainly black tea) at least once per month. During an average follow-up of 15.1 years, 301 women were diagnosed as having invasive epithelial ovarian cancer.

"We observed a 46 percent lower risk of ovarian cancer in women who drank two or more cups of tea per day compared with non-drinkers," the authors report. "Each additional cup of tea per day was associated with an 18 percent lower risk of ovarian cancer."

Women who drank less than one cup of tea per day had an 18 percent lower risk of ovarian cancer than non-drinkers. The risk was 24 percent lower for women who drank one cup of tea per day.

"This association does not depend on lower coffee consumption among women with high tea consumption; coffee is not associated with ovarian cancer risk in this cohort," the authors write.

"In summary, our results from a large population-based cohort of Swedish women suggest that tea consumption may lower the risk of ovarian cancer," the authors conclude. "Because prospective data on this relationship are scarce, our findings need confirmation by future studies."

(Arch Intern Med. 2005;165:2683-2686. Available pre-embargo to the media at www.jamamedia.org.)

Editor's Note: This work was supported by research grants from the Swedish Cancer Foundation and the Swedish Research Council/Longitudinal Studies, Stockholm, Sweden.


Adapted from materials provided by JAMA and Archives Journals, via EurekAlert!, a service of AAAS.

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Omega-3 Fatty Acids: A Way To Improve Heart Health, Eating Oily Fish May Reduce Inflammation

Daily Science Journal (Aug. 13, 2007) — While a heart-healthy diet has become synonymous with plenty of fruits and vegetables and little fat and cholesterol, there’s more to the story. Omega-3 fatty acids should be part of a heart-healthy diet, too, according to the August issue of Mayo Clinic Health Letter.

Omega-3 fatty acids are a form of polyunsaturated fat important to overall health. As it pertains to heart disease, their main benefit is their ability to reduce the risk of heart rhythm problems in certain groups of people, thus reducing the risk of sudden cardiac death. In addition, omega-3s may help reduce triglycerides, lower blood pressure slightly and reduce blood clotting.

The best source of omega-3s is fatty, cold water fish such as herring, mackerel, salmon and tuna. Plant oils, such as canola and flaxseed oils, also are sources of omega-3s.

For heart disease prevention, near-maximum benefit comes from eating two 3-ounce servings of cold water fish a week. More than that doesn’t appear to offer any additional preventive benefit.

Higher amounts of two kinds of omega-3, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), may benefit some people with established heart disease or high triglyceride levels and can have an anti-inflammatory effect for people with rheumatoid arthritis. In addition, DHA is being studied to see if it can slow the progression of Alzheimer’s disease.

For those who don’t eat fish, a fish oil supplement or an algae supplement can provide omega-3 fatty acids. However, supplements aren’t cheap, and the amount of DHA and EPA in supplements varies widely. Except for people who have established heart disease, the evidence of heart disease prevention is stronger when one eats fish instead of taking supplements. Supplements can pose risks, too. Taking more than 3 grams of fish oil a day may increase the risk of bleeding, worsen heart rhythm problems in those who have arrhythmias or cause other side effects.

Adapted from materials provided by Mayo Clinic, via Newswise.

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Eating Oily Fish May Reduce Inflammation

A new study explains how a diet high in oily fish like salmon and mackerel improves inflammatory conditions, particularly in combination with low doses of aspirin. In a study in the March 7 issue of The Journal of Experimental Medicine, Arita and colleagues identify an anti-inflammatory lipid in humans that is derived from an essential fatty acid in fish oil.

Sockey Salmon. (Photo courtesy of Washington State Department of Fish and Wildlife)

Fatty fish contain large amounts of omega-3 fatty acids--diet-derived essential fatty acids known to benefit patients with cardiovascular disease and arthritis. This research group recently identified a new class of aspirin-triggered bioactive lipids, called resolvins, the activity of which may in part explain the beneficial effects of omega-3 fatty acids. Resolvins are made from the omega-3 fatty acids by cellular enzymes and can reduce inflammation in mice. The main bioactive component of this class of lipids was identified in mice and named resolvin E1.

The researchers have now identified this lipid in plasma taken from volunteers given omega-3 fatty acids and aspirin. Human resolvin E1, the authors show, inhibits both the migration of inflammatory cells to sites of inflammation and the turning on of other inflammatory cells.

This study also reveals a potential pitfall of COX-2 inhibitors, drugs designed to block inflammation, which have been shown to have negative cardiovascular side effects. COX-2 is involved in making resolvin E1 and the authors suggest that inhibition of vascular COX-2 by these inhibitors might block the synthesis of resolvin E1, which would eliminate an important anti-inflammatory pathway. The experiment to prove this idea, however, has yet to be done.

Adapted from materials provided by Journal Of Experimental Medicine.

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Green Tea Holds Promise As New Treatment For Inflammatory Skin Diseases, Tea Extracts Help Treat Damaged Skin In Cancer Patients

Daily Science Journal (Aug. 7, 2007) — Green tea could hold promise as a new treatment for skin disorders such as psoriasis and dandruff, Medical College of Georgia researchers say.

Dr Hsu says, "There are no cures for autoimmune diseases. But it is possible that this is a non-toxic way to regulate them. We need further study -- on humans -- to determine the full effects." (Credit: Medical College of Georgia)

Researchers studied an animal model for inflammatory skin diseases, which are often characterized by patches of dry, red, flaky skin caused by the inflammation and overproduction of skin cells. Those treated with green tea showed slower growth of skin cells and the presence of a gene that regulates the cells' life cycles.

"Psoriasis, an autoimmune disease, causes the skin to become thicker because the growth of skin cells is out of control," says Dr. Stephen Hsu, an oral biologist in the MCG School of Dentistry and lead investigator on the study published in the Aug. 18 edition of Experimental Dermatology. "In psoriasis, immune cells, which usually protect against infection, instead trigger the release of cytokines, which causes inflammation and the overproduction of skin cells."

Other autoimmune diseases with similar side effects include lupus, which can lead to skin lesions, and dandruff.

Green tea, already shown to suppress inflammation, helps by regulating the expression of Caspase-14, a protein in genes that regulates the life cycle of a skin cell.

"That marker guides cells by telling them when to differentiate, die off and form a skin barrier," Dr. Hsu says. "In people with psoriasis, that process is interrupted and the skin cells don't die before more are created and the resulting lesions form."

Animal models treated with green tea also showed reduced levels of proliferating cell nuclear antigen, a gene expressed when skin cells multiply. In psoriasis, the gene is over-expressed and speeds production of skin cells.

"Before treatment, the antigen, PCNA, was present in all layers of the skin," Dr. Hsu says. "Typically, PCNA is only found in the basal layer, the innermost layer where skin cells continually divide and new cells push the older ones to the skin surface, where they eventually slough off. After being treated with green tea, the animal models showed near-normal levels of PCNA in only the basal layers."

This research is important because some treatments for psoriasis and dandruff can have dangerous side effects, he says.

"The traditional treatment of ultraviolet light and medication, while it can control the lesions and be used long term, may cause squamous cell carcinoma – the second most common form of skin cancer," Dr. Hsu says. "Some of the most effective anti-dandruff shampoos also have carcinogens in them. While the U.S. Food and Drug Administration allows that in small amounts, the bottom line is that we don't know the long-term effects of using those products continuously."

Green tea, which is plant-derived, may be an alternative, he says. But scientists must work to overcome some barriers with the treatment.

The chemicals in green tea are so active that they are oxidized too quickly when mixed with other ingredients. They also dissolve in water, which cannot penetrate the skin's barrier.

Researchers are looking for a balanced formula that can dissolve in fats, which can permeate the skin, Dr. Hsu says.

Adapted from materials provided by Medical College of Georgia.

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Tea Extracts Help Treat Damaged Skin In Cancer Patients

Tea extracts work as an effective treatment for patients who suffer from damaged skin following radiation treatment for cancer. Researchers show that this might partly be due to the anti-inflammatory properties of tea.

In a study published in the open access journal BMC Medicine, researchers show that tea acts at the cellular level, by inhibiting inflammatory pathways, to reduce inflammation. They also show that tea extracts reduce the duration of radiation-induced skin damage by up to 10 days in patients who received radiation treatment.

Frank Pajonk, from the University of California in Los Angeles, USA, and colleagues from the University of Freiburg, Germany, studied the effects of green tea and black tea extracts on patients who had been treated with radiotherapy, which can damage the skin. The authors then analysed the effects of the same tea extracts on human and mouse white blood cells in culture.

Pajonk et al. find that tea extracts reduce the duration of skin toxicity following radiotherapy by 5 to 10 days. Green tea extracts are more effective than black tea extracts in some patients. Pajonk et al. also show that tea extracts reduce the release of pro-inflammatory cytokines, such as IL-1beta, IL-6, IL-8, TNFalpha and PGE2, in human white blood cells in culture, with green tea having higher anti-inflammatory properties than black tea. Both black tea and green tea inhibit one major inflammatory pathway in mouse white blood cells.

Pajonk et al. add that tea's high content of polyphenols is likely to be responsible for its high anti-inflammatory activity, but that other pathways are probably involved in its clinical effectiveness.

Adapted from materials provided by BioMed Central, via EurekAlert!, a service of AAAS.

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