A new study finds that treatment for acute back pain may decrease or remove the complaint of pain, but additional and/or other treatment may be required for the chronic, longer term disability that develops in the 65-90% of population that develops acute low back pain.

Low Back Pain Eases but Doesn't Vanish

 

By Rita Baron-Faust, Contributing Writer, MedPage TodayPublished: May 14, 2012

Reviewed by Zalman S. Agus, MD; Emeritus Professor, Perelman School of Medicine at the University of Pennsylvania and Dorothy Caputo, MA, BSN, RN, Nurse Planner

Symptoms of acute and persistent low back pain improved significantly in the first 6 weeks after treatment, but even at 1 year there was lingering chronic pain and disability, a major meta-analysis by Australian and Brazilian researchers found.

Mean pain scores (52 out of a maximum of 100, 95% CI 48 to 57) at baseline were reduced by almost half after 6 weeks (12 out of 100, 95% CI 9 to 15) but pain lingered for months, the researchers reported online in CMAJ. The study encompassed data from prospective cohort studies conducted among more than 11,000 people in a dozen countries.

Outcomes were found to be similar across all cohorts, with improvement gradually slowing and "even at 1 year, patients had low to moderate levels of pain and disability," wrote Christopher G. Maher, PhD, of the University of Sydney, and colleagues.

While the data did not include the exact nature of the back pain nor the treatments, "the important conclusion that can be drawn from the data is that much of the apparent benefits of any treatment for low back pain are likely to be unrelated to the effects of specific interventions," wrote Rachelle Buchbinder, MBBS, PhD, of Monash University in Malvern, in an accompanying commentary.

About 80-90% of the population gets l0w back pain at some point in time and about 25% would report having back pain in the past week, Buchbinder noted in an e-mail to MedPage Today.

Current treatments are aimed at symptom relief and "we are not going to get more effective treatments until we better understand the pathoanatomical basis of back pain," Maher said in an email interview. 

Recovery was measured in 19 (56.6%) of the included inception cohorts (meaning the patients were enrolled when the episode of low back pain was first reported). The majority of acute back pain patients had recovered by 12 weeks. Among those with persistent low back pain, less than half had recovered by one year, the investigators said.

The pooled estimates of the clinical course of pain and disability were determined with mixed linear models. Acute low back pain cohorts were defined as those with a mean or median pain duration of less than 6 weeks; persistent low back pain was defined as pain duration of more than 6 weeks at study entry.

"The clinical course of pain and disability in the acute pain cohorts was similar and the difference not statistically different (p=0.20). However, the clinical course of pain was more favorable than the clinical course of disability in the persistent pain cohorts (p=0.002)," Maher's team reported.

The mean reduction in pain and disability scores within the first month was 58%.

It is difficult to prevent low back pain and, while a minority of people become disabled by their pain, the idea "that disability, rather than low back pain, persists is an important pointer for improving our interventions," Buchbinder noted in her commentary.

Many patients are getting out-of-date treatments rather than treatments that are known to be effective, Maher remarked in his email to MedPage Today.

Both authors concluded that back pain, like other health problems, should now be regarded as a chronic and long-term, and that patients should be better educated about its nature and the likelihood of recurrence.

"Back pain should be considered as a chronic recurring condition which means that we should reconsider how we manage it. A one-off visit when it (the pain) is bad is not likely to provide the best outcome," said Maher.

There was no specific funding for this study.
Christopher Maher is supported by the Australia Research Council. Co-authors reported support from Australia's National Health and Medical Research Council, the University of Sydney, and Fundação de Amparo a Pesquisa do Estado de São Paulo, Brazil.

Primary source: CMAJ
Source reference:
Costa OP, et al "The prognosis of acute and persistant low-back pain: A meta-analysis" CAMJ 2012; DOI: 10.1503/cmaj.111271.

Additional source: CMAJ
Source reference:
Buchbinder R, Underwood M "Progosis in people with back pain" CMAJ 2012; DOI: 10.1503/cmaj.120627.

Mom on toddler injuries - Old: "Don't run with that lollipop in your mouth!" New: "Don't run with that sippy-cup in your mouth!"

Binky, Sippy Cup Can be Source of Trip to the ER

 

By Rita Baron-Faust, Contributing Writer, MedPage TodayPublished: May 14, 2012

Reviewed by Robert Jasmer, MD; Associate Clinical Professor of Medicine, University of California, San Francisco.

More than 45,000 U.S. children under age 3 required emergency treatment after suffering injuries sustained from seemingly harmless bottles, pacifiers, or sippy cups over the last 2 decades, according to a database review.

The vast majority of the estimated injuries occurred after the toddler fell (86.1%, 95% CI 33,103 to 45,097) in the home, usually while drinking from a baby bottle, which caused lacerations or contusions to the mouth or face, reported Sarah Keim, PhD, from the Research Institute at Nationwide Children's Hospital in Columbus, Ohio, and colleagues in Pediatrics.

Almost all infants and toddlers use bottles, pacifiers (often referred to as a binky), and sippy cups for supplying nutrition, comfort, and convenience, but parents don't always include these items as part of a baby-proofing scheme. "Parents do a lot of things to baby proof their home and make sure children's toys are safe, but often don't give a second thought to these products," Keim told MedPage Today.

This study is the first to use a nationally representative sample to examine injuries associated with these products, the authors stated.

They analyzed data from the National Electronic Injury Surveillance System (NEISS) and found that an estimated 45,398 children under age 3 were treated in emergency departments for bottle-, pacifier-, or sippy cup-related injuries between 1991 and 2010, amounting to one child being treated every 4 hours.

The children were stratified according to gender and age, from less than 1 year, 1 year, and ages 2 to 3.

The analysis found that 66.4% of injuries (95% CI 25,538 to 34,740) occurred in children younger than 1 year because of falls while using a bottle (57.5%) or a pacifier (33.8%).

Compared with younger children, 1-year-olds were 7.62 times more likely to fall (95% CI 4.84 to 12.02). At this age, children are just learning to walk, are unsteady on their feet, and are prone to falls, Keim noted. Most injuries occurred among boys (61.2%), who tend to be more active, she added.

The most commonly injured body regions were the mouth (71%), followed by the head, face, or neck (19.6%).

Overall, most injuries involved a bottle (65.8%, 95% CI 25,245 to 34,525), followed by a pacifier (19.9%, 95% CI 7,108 to 10,935), and a cup with a drinking spout lid (14.3%, 95% CI 4,454 to 8,512).

Although lacerations were the main diagnosis across all products, pacifiers were associated with a higher likelihood of soft tissue injuries (OR 1.86, 95% CI 1.12 to 3.10) and dental injuries (OR 3.25, 95% CI 1.75 to 6.04) than bottles or sippy cups.

"With older children, one reason for falling could be not paying attention to where they are walking while drinking from a bottle or sippy cup, which could be compared to adults being distracted by texting while walking," Keim suggested to MedPage Today.

The national data likely underestimated the number of injuries because of a lack of reporting, Keim said. "Some pediatricians and dentists see some of these injuries in their practice, and many minor injuries are also treated at home," she said.

Data from the NEISS came from a network of around 100 hospitals, representing a stratified probability sample of 6,100 hospitals with ≥6 beds and a 24-hour emergency department. Population estimates used to calculate injury rates were derived from the U.S. Census Bureau.

No national rate could be calculated for 2010 because population estimates were unavailable, but actual injuries treated in EDs were estimated at 2,194.

The study was limited by a lack of comparable data for injuries treated outside the emergency department and a lack of comparison data of injuries that were unrelated to these products. The authors also had no information on which product characteristics were most involved in the injuries.

In 2005, the American Academy of Pediatrics issued guidelines recommending pacifier use as one mechanism for preventing sudden infant death syndrome (SIDS).

At the time, the Academy cited evidence from case-controlled studies that the arousal threshold may be reduced for infants put to sleep sucking on a pacifier. But the AAP stressed that suffocation by soft bedding and by infants sleeping on their stomachs were stronger risk factors.

Since the "Back to Sleep" campaign was initiated by the National Institute of Child Health and Human Development in 1994, the rate of SIDS has since dropped by 50%, but has lately plateaued. An AAP report noted earlier this year that sharing a bed with a parent has emerged as a prominent risk factor.

However, since SIDS remains the leading cause of death among infants, the AAP still recommends pacifier use at bedtime as a preventive measure until age 6 months, Keim noted.

Given the number of injuries from bottles, pacifiers, and sippy cups, Keim and co-authors advised that children not use these products beyond intended ages recommended by the AAP, and parents help their children transition to a lidless drinking cup around age 1.

The authors also recommend that parents encourage children to sit while they drink or eat, rather than walk around with a bottle or cup during the day and 'graze,' not only as a way of reducing accidents but also to develop better eating habits.

The authors have no relevant financial relationships to disclose.
There was no external funding for this story.

Primary source: Pediatrics
Source reference:
Keim S, et al "Injuries associated with bottles, pacifiers, and sippy cups in the United States, 1991-2010" Pediatrics 2012; 129; DOI: 10.1542/peds.2011-3348.

In new study, medicine discovers what holistic CAM providers have known all along - probiotics may help prevent antibiotic induced diarrhea. Truth be told, probiotics have many beneficial health outcomes.

Probiotics May Prevent Antibiotic Diarrhea

 

By Crystal Phend, Senior Staff Writer, MedPage TodayPublished: May 08, 2012

Reviewed by Dori F. Zaleznik, MD; Associate Clinical Professor of Medicine, Harvard Medical School, Boston and Dorothy Caputo, MA, BSN, RN, Nurse Planner

 

Probiotics appear to fight diarrhea that occurs as a common side effect of antibiotic treatment, a meta-analysis affirmed.

 

Probiotic administration was associated with a 42% reduced relative risk of antibiotic-associated diarrhea (P<0.001), Susanne Hempel, PhD, of RAND Health in Santa Monica, Calif., and colleagues found.

The number needed to treat to prevent one case of diarrhea from antibiotic use was just 13, they reported in the May 9 issue of the Journal of the American Medical Association.

Antibiotics lead to diarrhea in as many as 30% of patients, which is an important cause of nonadherence to the drugs.

"Potentially, probiotics maintain or restore gut microecology during or after antibiotic treatment through receptor competition, competition for nutrients, inhibition of epithelial and mucosal adherence of pathogens, introduction of lower colonic pH favoring the growth of nonpathogenic species, stimulation of immunity, or production of antimicrobial substances," the group suggested.

In children, probiotics have proven effective in preventing antibiotic-induced diarrhea and treating acute infectious diarrhea.

Most of the evidence, though, has accrued in adult trials almost universally underpowered to show the kind of impact seen in Hempel's analysis.

The meta-analysis included 82 randomized controlled trials, 57 of which used Lactobacillus-based interventions alone or in combination with other genera of probiotics (32 with Bifidobacterium). All but two trials used probiotics to prevent rather than treat existing antibiotic-associated diarrhea.

The effect on diarrhea risk could be pooled from 63 of the trials, with a total of 11,811 participants, and remained significant at P<0.001 when excluding any individual trial.

The trials where Lactobacillus probiotics was used exclusively were associated with reduced risk of antibiotic-associated diarrhea, similar to that in the overall analysis (pooled RR 0.64, P=0.004), with a number needed to treat of 14.

The 16 trials using only yeast as the probiotic, such as Saccharomyces boulardii [cerevisiae] or Hansen CBS 5926, also showed significantly reduced risk of antibiotic-associated diarrhea with a pooled relative risk of 0.48 (P<0.001) and number needed to treat of 10.

The researchers also looked for Streptococcus, Enterococcus, and Bacillus probiotic studies but found few.

Pooled results from three older trials using Enterococcus [Streptococcus] faecium SF68 showed a relative risk of 0.51 (P<0.001) and a number needed to treat of 12.

The difference between the different probiotic types wasn't significant (P=0.45) and didn't appear to explain away heterogeneity. Nor did the head-to-head comparison trials point to a clear winner.

The exact strains of the probiotic bugs used, though, were poorly documented, Hempel's group cautioned.
The analysis turned up no evidence of publication bias; no difference in probiotic treatment effect by conflict of interest status of the trials; and similar findings looking only at double-blind trials, or only at those with placebo control.

Nor did results vary for adults versus children, outpatient versus inpatient care, or by duration of antibiotic treatment.

In addition to unexplained heterogeneity among included trials and poorly documented probiotics, limitations of the study included lack of information from experts about published or unpublished studies.

"Determining which populations would benefit most from adjunct probiotics therapy is an ongoing challenge; it must be considered that antibiotic-associated diarrhea does not occur in the majority of patients and when it occurs, it is usually self-limiting," Hempel's group wrote.

Little data was available on probiotic-specific adverse events. In rare cases reported decades ago, serious adverse effects like fungemia and bacterial sepsis were reported with probiotics, the researchers noted.

The RAND Corporation internally funded the review, building on the literature database established for a contracted evidence report on the safety of probiotics commissioned by the Agency for Healthcare Research and Quality, and funded jointly by the National Institutes of Health and the FDA Center for Food Safety and Applied Nutrition.
The researchers reported having no conflicts of interest.

Primary source: Journal of the American Medical Association
Source reference:
Hempel S, et al "Probiotics for the prevention and treatment of antibiotic-associated diarrhea: a systematic review and meta-analysis" JAMA 2012; 307: 1959-1969; DOI: 10.1001/jama.2012.3507.
 

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Good news for those with diabetes as new study indicates weight loss can prevent or cure the disease. Toward that goal, a low glycemic index - high fiber diet will greatly help.

Science News

... from universities, journals, and other research organizations

Losing Weight When Obese Can Prevent or Cure Diabetes, Whatever the Initial BMI, Study Suggests

ScienceDaily (May 6, 2012) — Lowering your BMI by five units can dramatically reduce your risk of diabetes, whatever your initial weight, says new research presented at the International Congress of Endocrinology/European Congress of Endocrinology in Florence, Italy. The findings show that even severely obese patients with diabetes can potentially rid themselves of the disease.

Addressing diabetes is a major priority for health providers worldwide given the vast global prevalence (approx. six to seven per cent of the world's population; around 285 million people) and its severe complications including amputations and heart disease. Surgery for weight loss has an unexpectedly rapid and substantial therapeutic effect on diabetes rates. Understanding why weight loss has such a dramatic effect on diabetes is the focus of this study by Associate Professor Markku Peltonen from the National Institute for Health and Welfare, Finland and colleagues from the University of Gothenburg, Sweden.

The researchers enrolled the 2010 patients from the Swedish Obese Subjects study who had received bariatric surgery and 2037 obese controls receiving conventional (non-surgical) obesity treatment.

They were assessed for BMI and diabetes at baseline (before surgery in the surgical group), and at two and 10 year follow-up.

Among patients with BMI<35, 35-40 and 40-45 who did not lose weight after two years, type 2 diabetes incidence rates were 6.5%, 7.7% and 9.3% respectively. Among those with initial BMI 35-40, 40-45 and ≥45 who lost at least five BMI units after two years, type 2 diabetes incidence rates were 2.4%, 2.0% and 3.4% respectively, clearly showing that lower rates of diabetes can be found among obese patients who have lost five BMI units through any means. Further analysis showed that the rate of patients cured of diabetes after losing five BMI units was independent of the starting BMI at all BMI levels measured. This trend was also observed after 10 years post surgery.

The findings suggest that losing five BMI units, the equivalent of approx. 16kg for a 180cm tall 35 year old man weighing 130kg (BMI 40), can make a real difference to your health by reducing your likelihood of having type 2 diabetes. Furthermore, it suggests that this is true for all patients, as even those who were severely obese showed dramatic improvements.

Associate Professor Markku Peltonen, Director of Department at the National Institute for Health and Welfare, Finland, said:

"Our findings show that, whatever your starting weight, losing five BMI units can dramatically reduce your risk of having type 2 diabetes after two and ten years.

"Dropping five BMI units is no mean feat, as the human body is not very good at losing weight. But patients of any weight should take encouragement that by doing so they can really improve their chances of a healthy future."

Yet another study concludes: Jogging = Longer & Happier Life! Though for some, your knees might not be so happy.

Joggers Live Longer, Possibly Happier, Lives

 

By Peggy Peck, Executive Editor, MedPage TodayPublished: May 04, 2012

Reviewed by Dori F. Zaleznik, MD; Associate Clinical Professor of Medicine
Harvard Medical School, Boston.

DUBLIN -- For those who diligently lace up their running shoes and brave the elements to jog at least an hour a week, there is a very real reward -- an average of six more years of life, Danish researchers found.

Jogging was associated with a 44% reduction in the relative risk of death over 35 years compared with deaths among non-joggers, according to Peter Schnohr, MD, chief cardiologist from the Copenhagen City Heart study.

And the benefit was observed for both men and women.
That reduction translated into an "age-adjusted survival benefit of 6.2 years in men and 5.6 years in women," Schnohr reported here at EuroPRevent 2012.

And that longer life is often a happier life, he said, since joggers reported an overall sense of well-being.

"This is definitely good news, especially for those who have questioned whether simply jogging could be beneficial," said Ian Graham, MD, of Dublin's Trinity College, who co-chaired the program committee for the meeting.

"The results of our research allow us to definitively answer the question of whether jogging is good for your health," Schnohr said in a prepared statement. "We can say with certainty that regular jogging increases longevity. The good news is that you don't actually need to do that much to reap the benefits."

Moreover, even elderly people can add years to life by jogging. "A 70-year-old will benefit and I think the benefit may be even greater for older people," Schnohr said in an interview.

In this analysis the optimum benefit was realized for those who jogged at a slow-to-average pace between an hour and two and half hours done in two to three sessions over the course of a week.

The key, Schnohr said, appears to be moderation, much like the benefit observed with alcohol.
The jogging benefit is just the latest in a long list of studies from Schnohr and colleagues -- more than 750 papers -- mined from the 19,329 participants in the Copenhagen City Heart Study, which is a prospective cardiovascular population study begun in 1976.

When the study began, participants ranged in age from 20 to 79.

All participants underwent examinations over 2-year time frames beginning in 1976, 1981, 1991, and finally in 2001. In addition to assessments of cholesterol, blood pressure, blood glucose, and BMI, patients were also asked about smoking, alcohol consumption, education, and income.

The 1,878 participants in the jogging substudy (1,116 men) were also asked about jogging frequency and pace.

The researchers tracked the data using a personal identification number in the Danish Central Register. The authors compared deaths in joggers to deaths among non-joggers from the main study cohort.

During 35 years of follow-up there were 122 deaths among joggers versus 10,158 deaths among non-joggers.

Schnohr said said he had no relevant disclosures.

Primary source: European Association for Cardiovascular Prevention & Rehabilitation
Source reference:

Schnohr P "Jogging -- healthy or hazard symposium: Assessing prognosis: a glimpse of the future" EuroPRevent 2012.

In another case of "you are what you eat" a new study shows that eating berries may delay cognitive decline, once again demonstrating the anti-inflammatory properties of the flavinoids found in food.

From Medscape Medical News > Neurology

Eating Berries Linked to Delay in Cognitive Decline

Fran Lowry

May 1, 2012 — Increased consumption of blueberries and strawberries appears to slow cognitive decline in older women, according to an analysis of data from the Nurses' Health Study (NHS).

"Increasing berry intake appears to slow memory decline by up to 2.5 years," lead author, Elizabeth E. Devore, ScD, from the Channing Laboratory, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, told Medscape Medical News. "By this, we mean that women eating the most berries vs. little to no berries had memory differences equivalent to women 2.5 years apart in age."

The news study was published online April 25 in the Annals of Neurology.

Berries and Flavonoids
 
In their prospective, observational study, which was funded by the National Cancer Institute and the California Strawberry Commission, Dr. Devore and her team evaluated long-term intake of berries and flavonoids in relation to memory decline in 16,010 older women who were participants in the NHS.

The NHS encompasses a large population cohort of 121,700 female registered nurses aged 30 to 55 years who completed health and lifestyle questionnaires starting in 1976.

Between 1995 and 2001, cognitive function was measured every 2 years in study participants aged 70 and older. The mean age of the women in the current analysis was 74, and their mean body mass index was 26 kg/m².

"Experimental data show that berry supplementation enhances neuronal function and survival and ameliorates age-related cognitive impairment in rodents," Dr. Devore noted.

Berries are particularly high in a subclass of flavonoids called anthocyanidins, which can cross the blood-brain barrier and localize in the hippocampus, known to be an area of the brain involved in learning and memory, she said.

"Flavonoids have powerful antioxidant and anti-inflammatory properties, and both oxidative stress and inflammation are thought to be important contributors to cognitive impairment. So increased flavonoid consumption could be a potential strategy for reducing cognitive decline in older adults," she said.

The researchers found that greater intakes of blueberries and strawberries were associated with slower rates of cognitive decline.

After adjustment for age and education, greater consumption of blueberries was highly associated with slower decline in the global score (P trend = .010), the verbal score (P trend = .016), and the Telephone Interview of Cognitive Status (P trend = .027).

The mean difference in rate of global decline was 0.04 standard unit over the study period (95% confidence interval [CI], 0.01 - 0.07) in women who had 1 or more servings of blueberries per week vs those who ate less than 1 serving per week.

They also found that a greater intake of strawberries was related to slower decline in the global and verbal scores after adjustment for age (P trend for global score = .021) and education (P trend for verbal score = .014).

Women who ate 2 or more servings of strawberries per week had an average decline in the global score that was 0.03 standard unit less over the study follow-up period compared with women who had less than 1 serving per week (95% CI, 0.00 - 0.06).

Overall in the study population, the researchers found that 1 year of age was associated with a mean decline of 0.02 standard unit on the global score over the follow-up period.

"Thus, the mean differences that we observed comparing extreme categories of blueberry and strawberry intakes were equivalent to approximately 1.5 to 2.5 years of cognitive aging," Dr. Devore explained.

"Women with higher berry intake appeared to have delayed their cognitive aging by up to 2.5 years."
However, she cautioned that although the study controlled for other health factors, the possibility that the preserved cognition in those who ate more berries may be also influenced by other lifestyle choices, such as exercising more, cannot be ruled out.

The study does, however, have strengths, she said. "It is the first large epidemiologic study of long-term berry and flavonoid intake in relation to memory decline, utilizing information from over 16,000 older women. In addition, we collected information on berry intake over 20 years prior to initial memory testing, which enabled us to analyze long-term patterns of berry intake."

For now, however, doctors can tell their patients that eating berries may delay memory decline. "Specifically, eating 1 or more servings per week of blueberries or 2 or more servings per week of strawberries appears to be associated with memory benefits," Dr. Devore said.

Remain Skeptical
 
Commenting on this study for Medscape Medical News, David Knopman, MD, from the Mayo Clinic, Rochester, Minnesota, and a spokesperson for the American Academy of Neurology, agreed that the study did have its strengths, including the fact that mid-life dietary practices were assessed at the time, not retrospectively, and its inclusion of a very large number of women who had had 3 cognitive assessments.

However, he said he still has concerns about the study.

"The concerns that I have about the report stem primarily from the fact that studies of associations between dietary habits and health outcomes are notoriously difficult to replicate," Dr. Knopman said. "Second, the possibility of residual confounding by general health behavior, levels of physical activity, socioeconomic status is a possibility that cannot be discounted. The authors acknowledge this.

I would note that inclusion of physical activity and household annual income in the statistical models that they used attenuated the associations to the point that they were no longer significant.

 

"Further, I would note that inclusion of physical activity and household annual income in the statistical models that they used attenuated the associations to the point that they were no long significant at the p < 0.05 level for 2 of 3 of the cognitive outcomes," he said.

"The authors presented the results but did not comment on these analyses in the text of their article or in the abstract. I think that the authors should have said: 'When controlling for other health-related variables, the associations were attenuated and raise questions about the specificity of our findings.' Therefore, I remain skeptical that these results reflect what the authors say they do," Dr. Knopman said.

The study was funded by the National Cancer Institute and the California Strawberry Commission. Dr. Devore and Dr. Knopman have disclosed no relevant financial relationships.

An experimental new treatment involving enzyme injection into an acupuncture point shows promising response in proving longer relief from pain. More studies still need to be done, but....

Shot may top acupuncture for pain relief

 

Mouse study finds enzyme injection has lasting effects

By Tina Hesman Saey

ScienceNews Web edition : Friday, April 27th, 2012

 

A new treatment mimics acupuncture’s the pain-blocking mechanism of acupuncture but offers longer-lasting pain relief, at least in mice.

Injections of an enzyme called PAP into an acupuncture point behind the knees of mice relieved pain caused by inflammation for up to six days, Julie Hurt and Mark Zylka of the University of North Carolina at Chapel Hill report online April 23 in Molecular Pain. That’s almost 100 times longer than pain relief from acupuncture, which typically lasts about 1½ hours.

Long-lasting pain relief “is truly important, clinically,” says Maiken Nedergaard, a neuroscientist at the University of Rochester in New York. She and colleagues previously demonstrated that inserting and manipulating acupuncture needles causes the body to release a chemical called adenosine. Adenosine acts as a local anesthetic to slow down pain messages sent to the brain, she says.

“The beauty of Mark’s study is that it takes advantage of the molecular mechanism of acupuncture and improves upon it,” Nedergaard says.

Zylka had already been studying PAP, which stands for prostatic acid phosphatase, when Nedergaard’s research on the release of adenosine during acupuncture was published. The study gave him the idea that boosting adenosine at acupuncture points, which are located where nerves contact muscle, could be a localized way to treat pain. Adenosine lasts only minutes in the human body, so injections of the chemical itself were not an option.

But Zylka knew that PAP, which produces adenosine by breaking down adenosine monophosphate or AMP, lasts a long time and can continue churning out adenosine as long as it has a supply of AMP. Muscles are a ready source of AMP, itself a breakdown product of a molecule called ATP, which cells use for energy. So Zylka and Hurt decided to inject PAP into a space behind the knee, called the popliteal fossa. In people, doctors inject anesthetics at that spot, which encompasses the Weizhong acupuncture point.

PAP injections in mice with inflamed paws made the limbs less sensitive to heat and poking — but didn’t cause muscle weakness or other discernible side effects, the researchers found.

Other scientists have postulated that acupuncture releases feel-good chemicals called endorphins, which work all over the body. But the new study helps cement the idea that acupuncture really works locally, Nedergaard says.

Not only does PAP relieve inflammatory pain longer than acupuncture does, it also relieves nerve pain in mice, testing showed. Clinical studies in people have found that patients with nerve pain get worse after acupuncture, says Jon Levine, a professor of medicine at the University of California, San Francisco.

“Maybe what [Zylka] starts with is the core of what acupuncture does, but then goes beyond to do something acupuncture doesn’t do,” Levine says.

Zylka says that a company may soon start testing the enzyme as a pain reliever for humans.