A common pain cream, if rubbed on the skin during a heart attack, may prevent or reduce damage to the heart while interventions are administered. This discovery was made in a new study conducted by researchers at the University of Cincinnati.
Dr. Keith Jones, a researcher in the department of pharmacology and cell biophysics, says when capsaicin was applied to specific skin locations in mice, sensory nerves in the skin were found to trigger signals in the nervous system.
According to the researcher, these signals activate cellular "pro-survival" pathways in the heart, which protect the muscle.
Capsaicin is the main component of chili peppers and produces a hot sensation. It is also the active ingredient in several topical medications used for temporary pain relief.
The researcher is joining forces with Dr. Neal Weintraub, a UC Health cardiologist and director of UC's cardiovascular diseases division, and other clinicians to construct a translational plan to test capsaicin in a human population.
"Topical capsaicin has no known serious adverse effects and could be easily applied in an ambulance or emergency room setting well in advance of coronary tissue death. If proven effective in humans, this therapy has the potential to reduce injury and/or death in the event of a coronary blockage, thereby reducing the extent and consequences of heart attack," Jones says.
Revealing their findings, the researchers said that they observed an 85 percent reduction in cardiac cell death when capsaicin was used, and that a small incision made on the abdomen triggered an 81 percent reduction.
"Both this and the capsaicin effect are shown to work through similar neurological mechanisms. These are the most powerful cardioprotective effects recorded to date. This is a form of remote cardioprotection, using a skin stimulus that activates cardioprotection long before the blocked coronary artery is opened," Jones says.
Weintraub said that the finding offered an important distinction between existing therapies.
"All of the current interventions require the vessel to be opened before doctors can act, and since it takes time to elicit protection, tissue dies. This treatment will protect the heart before the vessel is opened while producing a strong protective effect that is already active when we open the vessel," he said.
The researchers believe that skin-the main sensor and largest human body organ-has evolved to protect animals, including humans, in a variety of ways.
"By activating these sensors in the nervous system, via skin, we think that a response to preserve and protect the heart is triggered," Weintraub said.
"We think that this technique is fooling the body into sending out protective signals. This may be similar to the way certain acupuncture treatments work; there may be a neurological basis. In a broad sense, this work may provide a 'Rosetta stone' for translating alternative medicine techniques-like acupuncture-to Western medicine. Perhaps we can understand the biological mechanisms of how alternative treatments may be successful for patients," Jones added.
The research team have plans to explore this concept by researching into which sensors are associated with certain aspects of organ protection, and how much of specific stimuli are needed to produce the desired responses.
"This could help create favourable outcomes for those who are experiencing stroke, shock or are in need of an organ transplant, and the best part is that it is done non-invasively and is relatively inexpensive," Jones said.
He, however, warns against rubbing capsaicin on the belly of a person who feels like he/she is having a heart attack.
"We don't know if it will work for all indications, for all patients, and we don't know if it will work over an extended amount of time. A major goal is testing this therapy in clinical trials, but we still need to study more about dosage and application-where we put it on the body for the best results. However, this has tremendous clinical potential and could eventually save lives," he says.
A research article on the study has been published in the journal Circulation.