A study of tadpoles suggests that destructive molecules linked to ageing and cancer could play an important role in healing.

Scientists investigating how tadpoles regrow severed tails found an unexpected link to oxygen molecules normally considered highly harmful to health.

Without the molecules, known as reactive oxygen species (ROS), the tails would not regenerate.

Reactive oxygen molecules damage DNA and cell membranes and are associated with heart disease, cancer, and ageing.


Millions of people take antioxidant supplements to combat their effects. Health advice also encourages people to increase their consumption of antioxidant-rich fruits and vegetables.

But the new research suggests that ROS may have a previously unknown beneficial role in the healing process.

A number of animals, especially amphibians such as frogs and salamanders, have regenerative powers not shared by mammals.

If a tadpole loses its tail, it will grow a new one within a week.

Scientists know that regeneration of body parts involves a genetic pathway called Wnt, but many aspects of it remain a mystery.

Unravelling the secrets of tadpole regeneration could on one day lead to new healing treatments.

Researchers at the University of Manchester found that several metabolic genes were activated during tail regeneration in tadpoles. They included those involved in the production of ROS, in particular the powerfully destructive molecule hydrogen peroxide.

A marked increase in hydrogen peroxide levels occurred after tadpole tails were docked which remained throughout the regeneration process.

Lead scientist Professor Enrique Amaya, whose findings appear in the journal Nature Cell Biology, said: "When we decreased ROS levels, tissue growth and regeneration failed to occur.

"Our research suggests that ROS are essential to initiate and sustain the regeneration response. We also found that ROS production is essential to activate Wnt signalling, which has been implicated in essentially every studied regeneration system, including those found in humans. It was also striking that our study showed that antioxidants had such a negative impact on tissue regrowth, as we are often told that antioxidants should be beneficial to health."

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  • There Are 4 Major Classes Of Breast Cancer

    Results of a massive gene analysis, published last month in the journal <em>Nature</em>, shows that there are <a href="http://www.huffingtonpost.com/2012/09/24/four-breast-cancer-types-genetics-genes_n_1909116.html">four major classes</a> of breast cancer, the Associated Press reported. "With this study, we're one giant step closer to understanding the genetic origins of the <a href="http://www.siteman.wustl.edu/ContentPage.aspx?id=6431">four major subtypes of breast cancer</a>," study researcher Matthew Ellis, M.B., B.Chir., Ph.D., of the Washington University School of Medicine and the Siteman Cancer Center, said in a statement. "Now, we can investigate which drugs work best for patients based on the genetic profiles of their tumors," he added in the statement. "For basal-like breast tumors, it's clear they are genetically more similar to ovarian tumors than to other breast cancers. Whether they can be treated the same way is an intriguing possibility that needs to be explored."

  • Men With Breast Cancer Fare Worse

    Men are less likely to get breast cancer than women -- but when they do, it's <a href="http://www.huffingtonpost.com/2012/05/04/breast-cancer-men_n_1479739.html">often deadlier</a>, according to a study presented earlier this year at the American Society of Breast Surgeons meeting. The Associated Press reported that <a href="http://www.huffingtonpost.com/2012/05/04/breast-cancer-men_n_1479739.html">men diagnosed with breast cancer</a> live, on average, two fewer years than women who are diagnosed with breast cancer, and are also more likely to have the breast cancer spread, have larger tumors when the cancer is discovered, and be diagnosed later.

  • Cadmium Could Raise Breast Cancer Risk

    Cadmium -- a toxic metal that can be present in foods like shellfish, root vegetables, offal and cereals -- may <a href="http://www.huffingtonpost.com/2012/03/15/cadmium-breast-cancer-intake_n_1347523.html">raise risk of breast cancer</a>, according to a March 2012 study in the journal <em>Cancer Research</em>. The research included 56,000 women. Researchers were able to analyze about how much cadmium each woman was consuming based on the cadmium-rich foods in her diet. They found that those who <a href="http://www.huffingtonpost.com/2012/03/15/cadmium-breast-cancer-intake_n_1347523.html">consumed the most cadmium</a> had a 21 percent higher breast cancer risk, compared with those who consumed the least cadmium, HuffPost's Catherine Pearson reported.

  • Sleep May Affect Breast Cancer Risk

    Getting six or fewer hours of sleep <a href="http://www.huffingtonpost.com/2012/09/06/sleep-breast-cancer-aggressive-deprivation_n_1854658.html">may raise the risk of recurrent breast cancer</a> among post-menopausal breast cancer patients, according to a study in the journal <em>Breast Cancer Research and Treatment</em>. However, this same link was not observed for pre-menopausal breast cancer patients. The findings suggest "that <a href="http://www.uhhospitals.org/about/media-news-room/current-news/2012/08/lack-of-sleep-found-to-be-a-new-risk-factor-for-aggressive-breast-cancers">lack of sufficient sleep</a> may cause more aggressive tumors, but more research will need to be done to verify this finding and understand the causes of this association," study researcher Cheryl Thompson, Ph.D. said in the statement.

  • A Smallpox Virus Could Be A Promising Treatment

    A <a href="http://www.eurekalert.org/pub_releases/2012-10/acos-afo092712.php">smallpox virus</a> seems to be promising against a hard-to-treat form of breast cancer, called triple-negative breast cancer, according to a study in mice presented at the 2012 Annual Clinical Congress of the American College of Surgeons. "Based upon pathology, we could see that at least 60 percent of the <a href="http://www.eurekalert.org/pub_releases/2012-10/acos-afo092712.php">tumors were completely regressed</a> and the other 40 percent had very little areas of tumor cells present with a lot of necrosis, which is a sign that the tumor was responding to therapy," study researcher Dr. Sepideh Gholami, M.D., of Stanford University Medical Center, said in a statement. ABC News pointed out that this <a href="http://abcnews.go.com/blogs/health/2012/10/01/smallpox-virus-may-help-treat-deadly-form-of-breast-cancer/">kind of breast cancer is notoriously hard to treat</a> because it doesn't respond to other hormonal or immune treatments.

  • Shift Work May Influence Breast Cancer Risk

    Working the night shift is linked to an increased risk of breast cancer, according to two different studies that came out this year. One of them, published in the journal <em>Occupational and Environmental Medicine</em>, showed that <a href="http://www.huffingtonpost.com/2012/05/30/shift-work-breast-cancer-risk_n_1553058.html">breast cancer risk went up </a>among women who worked the night shift more than twice a week, with the risk being the highest among those who said that they are "morning people" instead of "night people." <em>The Toronto Sun</em> reported that the results of this study confirm the findings of the International Agency for Research on Cancer, which has a list of items and <a href="http://www.torontosun.com/2012/05/29/night-shift-work-linked-to-breast-cancer-risk">habits that may cause cancer</a>. The IARC considers shift work "possibly carcinogenic." The other study, published in the <em>International Journal of Cancer</em>, showed that breast cancer risk is 30 percent higher for <a href="http://www.huffingtonpost.com/2012/07/01/shift-work-breast-cancer-night-sleep_n_1612486.html">women who work the night shift</a>, with the risk being especially clear among those working night-time jobs for four years, or those who worked the night shift for three or fewer nights a week.

  • Breast Size May Be Linked With Breast Cancer Risk

    The genes that help determine a <a href="http://www.huffingtonpost.com/2012/07/05/breast-cancer-risk-breast-size-study_n_1652292.html">woman's breast size</a> may also be linked with her breast cancer risk, according to a study published earlier this year in the journal <em>BMC Medical Genetics</em>. Researchers examined the genetic data of 16,000 women to find that seven DNA variations, called single nucleotide polymorphisms (SNPs), seem to be <a href="http://www.huffingtonpost.com/2012/07/05/breast-cancer-risk-breast-size-study_n_1652292.html">linked with breast size</a> -- and three of those SNPs are known to be associated with a person's risk of breast cancer, HuffPost's Catherine Pearson reported.

  • Exercise Could Help Lower Breast Cancer Risk

    Just a little bit of exercise may help to <a href="http://www.huffingtonpost.com/2012/06/25/exercise-breast-cancer-risk-moderate_n_1619175.html">reduce your risk of breast cancer</a>, though the more you move, the better, according to a study in the journal <em>CANCER</em>. Researchers at the University of North Carolina in Chapel Hill found that postmenopausal or reproductive-age women in their study who exercised the most -- from 10 to 19 hours each week -- had a 30 percent <a href="http://www.huffingtonpost.com/2012/06/25/exercise-breast-cancer-risk-moderate_n_1619175.html">lower risk of breast cancer</a>, though exercising less than that was still linked with some protective benefits. "The observation of a reduced risk of breast cancer for women who <a href="http://www.eurekalert.org/pub_releases/2012-06/w-eem062012.php">engaged in exercise after menopause</a> is particularly encouraging given the late age of onset for breast cancer," study researcher Lauren McCullough said in a statement.

  • Type 2 Diabetes May Raise Breast Cancer Risk (For Some Women)

    For post-menopausal women, <a href="http://www.telegraph.co.uk/health/healthnews/9541796/Breast-cancer-risk-raised-by-Type-2-diabetes.html">having Type 2 diabetes</a> may raise the risk of breast cancer, according to a review conducted by the International Prevention Research Institute. "On the one hand, it's thought that being overweight, often <a href="http://www.telegraph.co.uk/health/healthnews/9541796/Breast-cancer-risk-raised-by-Type-2-diabetes.html">associated with Type 2 diabetes</a>, and the effect this has on hormone activity may be partly responsible for the processes that lead to cancer growth," study researcher Peter Boyle, the president of the International Prevention Research Institute, told <em>The Telegraph</em>. "But it's also impossible to rule out that some factors related to diabetes may be involved in the process."

  • Being Overweight Tied To Worst Breast Cancer Outcomes

    Being overweight could lead to worse outcomes from breast cancer, according to a study published August in the journal <em>Cancer</em>. Specifically, the study showed that overweight women who have been treated for breast cancer have a <a href="http://www.msnbc.msn.com/id/48800019/ns/health-cancer/t/being-overweight-tied-breast-cancer-return-death/#.UGxtN_mfGPI">higher risk of recurrence and death</a>, NBC News reported. "Obesity seemed to carry a <a href="http://www.msnbc.msn.com/id/48800019/ns/health-cancer/t/being-overweight-tied-breast-cancer-return-death/#.UGxtN_mfGPI">higher risk of breast cancer</a> recurrence and death -- even in women who were healthy at the time that they were diagnosed, and despite the fact that they received the best available chemotherapy and hormone therapy," study researcher Dr. Joseph Sparano, associate chairman of medical oncology at the Montefiore Einstein Center for Cancer Care, told NBC News.

  • Breast Cancer Stages and What They Mean

    Marisa Weiss, MD, of breast cancer.org, explains the different breast cancer stages and what they mean.

The study follows controversial claims by Dr James Watson, co-discoverer of the structure of DNA, that antioxidants may be harmful to people with late-stage cancer.

Writing in the journal Open Biology, he said reactive oxygen species help clear dysfunctional and dangerous cells from the body. Antioxidants may hinder cancer recovery by blocking their effect, he argued.

Professor Amaya added: "It's very interesting that two papers suggesting that antioxidants may not always be beneficial have been published recently.

"Our findings and those of others are leading to a reversal in our thinking about the relative beneficial versus harmful effects that oxidants and antioxidants may have on human health, and indeed that oxidants, such as ROS, may play some important beneficial roles in healing and regeneration."

The team at the University of Manchester's Healing Foundation Centre now plans to study the role of ROS in healing and regeneration more closely.

Manipulating reactive oxygen species may improve the body's ability to heal and regenerate itself, the scientists believe.

Also on HuffPost:

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  • New Advice On Prostate Cancer Screening

    This year, the U.S. Preventive Services Task Force <a href="http://www.npr.org/blogs/health/2012/05/21/153234671/all-routine-psa-tests-for-prostate-cancer-should-end-task-force-says">recommended <em>against</em> routine prostate cancer screening</a> for men of all ages, noting its small benefits compared to the harms, published in the <em>Annals of Internal Medicine</em>. "We think the <a href="http://www.npr.org/blogs/health/2012/05/21/153234671/all-routine-psa-tests-for-prostate-cancer-should-end-task-force-says">benefit is very small</a>," Dr. Michael LeFevre, a member of the task force, told NPR's Shots blog. "Our range is between zero and one prostate cancer death avoided for every thousand men screened," which is minuscule compared to lives saved for screenings for conditions like colorectal cancer. A study published at the beginning of the year in the <em>Journal of the National Cancer Institute</em> seemed to back up the recommendations, noting that routine prostate cancer screening didn't seem to make a <a href="http://www.huffingtonpost.com/2012/01/06/prostate-cancer-screening-psa-test-deaths-men_n_1190558.html">difference in the risk of dying from prostate cancer</a>, Reuters reported. However, the American Society of Clinical Oncology issued advice after the USPSTF's recommendation, saying that whether a man gets routine prostate cancer screening should <a href="http://www.huffingtonpost.com/2012/07/17/prostate-cancer-screening-test-man-life-expectancy_n_1679499.html">depend on his life expectancy</a>. For example, men who aren't expected to live more than another 10 years should be discouraged from PSA testing, the Associated Press reported.

  • PSA Testing Could Mean Fewer Cases Of Deadly Prostate Cancer

    To add more to the research on prostate cancer screening, a study in the journal <em>Cancer</em> showed that routine PSA testing is linked with 17,000 fewer cases of the deadliest form of prostate cancer. "By not <a href="http://www.webmd.com/prostate-cancer/news/20120730/study-psa-testing-cuts-worst-prostate-cancers">using PSA tests</a> in the vast majority of men, you have to accept you are going to increase very serious metastatic disease threefold," study researcher Dr. Edward Messing, M.D., the chief of urology at the University of Rochester Medical Center, told WebMD. Specifically, researchers calculated that without routine prostate cancer screenings through PSA testing, 25,000 men would have been diagnosed with <a href="http://www.webmd.com/prostate-cancer/news/20120730/study-psa-testing-cuts-worst-prostate-cancers">metastatic prostate cancer</a> (a deadly form of prostate cancer where it has spread beyond the prostate to elsewhere in the body) in 2008, compared with the 8,000 who were actually diagnosed with metastatic prostate cancer that year, WebMD reported.

  • Working The Night Shift Could Raise Your Risk

    <a href="http://www.huffingtonpost.com/2012/10/25/night-shift-prostate-cancer-health_n_2003392.html">Working the night shift</a> is associated with a 2.77-times increased risk of prostate cancer, according to a study in the <em>American Journal of Epidemiology</em>. The study, conducted by Canadian researchers included 3,137 men with cancer and 512 men without cancer. The researchers also found that <a href="http://www.huffingtonpost.com/2012/10/25/night-shift-prostate-cancer-health_n_2003392.html">working the night shift</a> raised the risk of lung, colon, bladder, rectal and pancreatic cancers, as well as non-Hodgkin's lymphoma.

  • Surgery May Not Be The Best Option For Everyone With Prostate Cancer

    Surgery may not always be the best option for men whose prostate cancer is detected with an elevated PSA (prostate-specific antigen) level, according to a study in the <em>New England Journal of Medicine</em>. For men with early prostate cancer who received a <a href="http://abcnews.go.com/Health/ProstateCancer/surgery-rarely-best-prostate-cancer-study-suggests/story?id=16805902#.UJrg9m_A_kh">radical prostatectomy</a> (prostate-removal surgery), 47 percent died after 12 years, while 49.9 percent of men who just underwent observation died after 12 years, ABC News reported. Plus 81 percent of men who underwent the radical prostatectomy <a href="http://www.webmd.com/prostate-cancer/news/20120718/prostate-cancer-surgery-may-not-always-up-survival">experienced erectile dysfunction</a> in the two years following, and urinary incontinence plagued 17 percent of the men, WebMD reported. However, ABC News did note that men whose <a href="http://abcnews.go.com/Health/ProstateCancer/surgery-rarely-best-prostate-cancer-study-suggests/story?id=16805902#.UJrg9m_A_kh">PSA scores were extremely high</a> -- above 10 -- benefited from receiving surgery, indicating that the study may suggest rather <em>which</em> men may benefit most from receiving a radical prostatectomy for their prostate cancer.

  • Aspirin Could Help Prostate Cancer Patients Live Longer

    Prostate cancer patients who <a href="http://www.nytimes.com/2012/08/28/health/research/regular-aspirin-use-may-aid-prostate-cancer-recovery-study-finds.html">take aspirin</a> could cut their risk of dying from the disease, Harvard researchers reported this year. <em>The New York Times</em> reported on the study, published in the <em>Journal of Clinical Oncology</em>, which showed that taking aspirin cut in half the risk of <a href="http://www.nytimes.com/2012/08/28/health/research/regular-aspirin-use-may-aid-prostate-cancer-recovery-study-finds.html">dying of prostate cancer</a> over a decade -- 8 percent of aspirin-nontakers died, compared with 3 percent of aspirin-takers.

  • Circumcision Could Affect Risk

    Circumcision -- or the removal of a man's foreskin before he has sex for the first time -- is linked with a <a href="http://www.huffingtonpost.com/2012/03/12/circumcision-prostrate-cancer_n_1339047.html">lower risk of developing prostate cancer</a>, Fred Hutchinson Cancer Research Center scientists found this year. The findings, published in the journal <em>Cancer</em>, shows that prostate cancer risk for <a href="http://www.huffingtonpost.com/2012/03/12/circumcision-prostrate-cancer_n_1339047.html">men who are circumcised</a> before the first time they have sex is 15 percent lower, compared with uncircumcised men. While Dr. Andrew Freedman, who is on the American Academy of Pediatrics' circumcision task force but was not involved in the study, found the findings thought-provoking, he told HuffPost in an earlier article that "this kind of epidemiological research -- how A affects B, and B affects C -- is very difficult to do and makes it very difficult to account for confounding variables."

  • Pan-Fried Meat Could Raise Risk

    Including <a href="http://www.huffingtonpost.com/2012/08/20/pan-fried-meat-cancer-prostate-_n_1798970.html">pan-fried meat</a> in your weekly meal rotations is linked with a higher risk of prostate cancer, University of Southern California researchers found. Specifically, men who eat one-and-a-half servings of red meat that's been pan-fried each week have a 30 percent <a href="http://www.huffingtonpost.com/2012/08/20/pan-fried-meat-cancer-prostate-_n_1798970.html">increased risk of advanced prostate cancer</a>. And men who eat two-and-a-half servings of the food have a 40 percent increased risk. Hamburger meat in particular -- compared with a red meat like steak -- seemed linked with the increased risk, according to the <em>Carcinogenesis</em> study. And while not a red meat, pan-fried poultry also seemed linked with the <a href="http://www.huffingtonpost.com/2012/08/20/pan-fried-meat-cancer-prostate-_n_1798970.html">increased prostate cancer risk</a> (while <em>baked</em> poultry was associated with a lower prostate cancer risk).

  • Genetic 'Signatures' Could Predict Aggressive Disease

    Genes could hold a clue to who will go on to <a href="http://www.huffingtonpost.com/2012/10/09/prostate-cancer-genetic-signatures-aggressive-tumors_n_1949724.html">develop aggressive prostate cancer</a>, researchers found this year. Reuters reported on the <em>Lancet Oncology</em> study, showing aggressive tumors might be able to be predicted by two <a href="http://www.huffingtonpost.com/2012/10/09/prostate-cancer-genetic-signatures-aggressive-tumors_n_1949724.html">genetic "signatures</a>": <blockquote>Researchers in Britain and the United States found that by reading the patterns of genes switched on and off in blood cells, they could accurately detect which advanced prostate cancer patients had the worst survival rates.</blockquote>

  • Blood Pressure Could Affect Risk Of Dying From Prostate Cancer

    The risk of dying from prostate cancer is higher if you also<a href="http://www.huffingtonpost.co.uk/2012/10/23/blood-pressure-prostate-cancer-deaths_n_2004582.html?just_reloaded=1"> have high blood pressure</a>, European researchers found. Specifically, hypertension was linked with a 62 percent increased risk of dying for people with prostate cancer. "When we looked to see if the metabolic factors are related to an increased risk of getting or dying from prostate cancer we found a relationship with <a href="http://www.huffingtonpost.co.uk/2012/10/23/blood-pressure-prostate-cancer-deaths_n_2004582.html?just_reloaded=1">death from the disease and high blood pressure</a>," study researcher Christel Haggstrom, of Umea University, told HuffPost UK. "There was also a link to high BMI but blood pressure had the strongest association to increased risk. The results for BMI are in line with previous findings in large studies."

  • Green Tea Is Good

    Research presented at the annual meeting of the American Association for Cancer Research this year showed that drinking green tea could <a href="http://www.eurekalert.org/pub_releases/2012-10/aafc-gtr101112.php">help ward off inflammation</a> in men with prostate cancer who are about to undergo prostate-removal surgery. "Our study showed that <a href="http://www.eurekalert.org/pub_releases/2012-10/aafc-gtr101112.php">drinking six cups of green tea</a> affected biomarkers in prostate tissue at the time of surgery," study researcher Susanne M. Henning, Ph.D., R.D., of the David Geffen School of Medicine at the University of California Los Angeles, said in a statement. "This research offers new insights into the mechanisms by which green tea consumption may reduce the risk for prostate cancer by opposing processes such as inflammation, which are associated with prostate cancer growth."

  • Living Longer With Prostate Cancer

    In this medical video learn more about the treatments that are enabling men to live longer with prostate cancer.