How to make stressed out

Stressed-out mice may have serendipitiously cued researchers in to a treatment for hair loss.

The mutant mice bred to overproduce a stress hormone called “corticotrophin-releasing factor” became bald on their backs as they aged. But after a week of daily injections with a compound to block CRF — called astressin-B — developed by the group to treat gastrointestinal disease, the mice unexpectedly regrew their missing hair and were indistinguishable from controls.

The effect remained for up to four months, which the researchers pointed out in a press release is a long time in a mouse’s less than two-year life span. It far exceeded the mild regrowth produced by minoxidil (Rogaine) in the same mouse model, the group reported in the journal PLoS One.

Since CRF is also expressed in human skin, the researchers expressed optimism that a similar approach could be a “breakthrough therapy for alopecia.”

– C.P.

Bone Hormone Has Effects on Testosterone

The interaction between the skeletal system and reproduction was thought to be a one-way street running from the gonads to the bones.

But now, studies by Dr. Gerard Karsenty of Columbia University and colleagues show that bones may have a say in male fertility, at least in mice.

The team had previously observed that mice whose skeletons did not secret the hormone osteocalcin had problems reproducing.

So, as reported in Cell, the researchers conducted some in vitro and in vivo studies showing that osteocalcin enhances the production of testosterone. When osteocalcin was not present, testosterone levels dropped, as did sperm count.

“This study expands the physiological repertoire of osteocalcin and provides the first evidence that the skeleton is an endocrine regulator of reproduction,” Karsenty and his colleagues wrote.

If confirmed in humans, the findings may explain why some men have low levels of testosterone, and could open the possibility of drugs that mimic osteocalcin to treat infertility.

The researchers noted that there is evidence that a similar phenomenon occurs in men — osteocalcin is found in human testes and the hormone is an indicator of glucose intolerance in both mice and men, suggesting similar behavior.

– T.N.

New Vessels to Heal Old Bone

Disrupted blood vessels are a common reason why broken bones fail to rejoin on their own. That has prompted efforts to stimulate vessel growth artificially near the fracture sites.

Attempts to use angiogenic growth factors such as VEGF for this purpose have failed to yield consistently good results. But in a study reported this week at the American Academy of Orthopaedic Surgeons’ meeting in San Diego, researchers from St. Michael’s Hospital in Toronto suggested that a stem-cell therapy might do the trick.

A gel foam impregnated with endothelial progenitor cells greatly accelerated healing of severed femur bones in rats, according to the researchers’ report. Moreover, the healed femurs showed biomechanical properties approaching those of intact bone.

– J.G.

Opioids Work If You Believe They Do

Although many would relegate the subject of the ‘power of positive thinking’ to self-help books or women’s magazines, a new study gives it some cred in terms of pain relief — and upholds its converse as well.

When patients in a study were told that their pain would be eased by a powerful opioid, a biting heat stimulus became far less so. But when subjects were made to believe that the narcotic wouldn’t help in the least, they felt no relief.

Dr. Ulrike Bingel of the University Medical Center Hamburg-Eppendorf and her colleagues took 22 healthy volunteers and put them through two procedures that subjected their legs to brief heat stimuli as they lay in an MRI machine.

Patients were told that the drug, Ultiva, would alleviate pain, have no effect, or exacerbate their pain.

The self-reported pain ratings were corroborated by MRI brain scans that showed heightened or diminished activity in pain processing regions.

Those who expected pain relief had activity in the endogenous pain modulatory system; those who expected no help from the drug had activity in the hippocampus.

Bingel and colleagues, writing in Science Translational Medicine, said the findings suggest that it may be necessary to take patients’ expectations into account in order to optimize their therapeutic regimens.