Vibration stimulation of external ear alleviates inflammation in RA
The application of a device that uses vibration to stimulate the cymba concha on the external ear can inhibit the production of TNF, IL-1 beta, and IL-6 in healthy individuals, as well as improve symptoms in patients with rheumatoid arthritis, according to data published in Bioelectronic Medicine.
“Transcutaneous auricular vagus nerve stimulation (taVNS) is an investigational therapy in which electrical signals are applied to the cutaneous territory supplied by the auricular branch of the vagus nerve,” Sangeeta S. Chavan, PhD, of the Feinstein Institute for Medical Research at Northwell Health in Manhasset, New York, and colleagues wrote. “We have reported that transcutaneous mechanical activation of the cervical vagus nerve is therapeutically efficacious in murine models of sepsis. Pressure applied directly to the skin overlying the cervical vagus nerve dose-dependently attenuated serum TNF levels during lethal endotoxemia.”
They added, “These studies demonstrated that transcutaneous mechanical stimulation of the vagus nerve attenuates serum inflammatory cytokine levels, and enhances survival in model of cytokine-mediated disease.”
To analyze the impact of applying a vibrotactile device to the external ear’s cymba concha on inflammatory responses in healthy individuals, as well as on disease activity among patients with RA, Chavan and colleagues conducted two studies: one at the Academic Medical Center at the University of Amsterdam and one at the Feinstein Institute for Medical Research. In Amsterdam, six healthy participants received vibrotactile treatment. The researchers assessed TNF production in the blood prior to stimulation, as well as at 30 minutes, 2 hours, 4 hours and 24 hours after stimulation.
Researchers at the Feinstein Institute for Medical Research conducted a randomized cross-over study, in which 19 healthy participants received vibrotactile stimulation at either the cymba concha or the gastrocnemius muscle. Participants received two treatments, separated by at least 1 week, but no more than 2, weeks. Blood was collected prior to stimulation and at 1 hour after during both visits. In addition, nine patients with RA were admitted for a 48-hour period and treated with vibrotactile stimulation twice daily. Examiners assessed these patients at admission as well as 48 hours and 7 days following treatment.
The vibrotactile device was designed and built for the clinical studies by Mass Bay Engineering. It consists of a handheld probe with a motor that spins an eccentric counterweight at the tip. The device is manually applied by an operator with a force of 0.15 kg.
According to the researchers, the stimulation treatment reduced TNF levels for up to 24 hours. Vibrotactile treatment of the cymba concha, but not the gastrocnemius muscle, significantly reduced TNF (P < .05), IL-1 beta (P < .001), and IL-6 (P < .01) levels compared with baseline. Overall, the stimulation treatment at the cymba concha among healthy participants inhibited TNF by 80%, IL-6 by 73% and IL-1 beta by 50% compared with baseline levels.
Among patients with RA, the researchers observed a significant decrease in Disease Activity Score in 28 joints C-reactive protein (DAS28-CRP) 48 hours following treatment at the cymba concha. DAS28-CRP score prior to stimulation was 4.19±0.33, compared with 3.12±0.25 after treatment (P < .05). This effect on disease activity persisted for 7 days following stimulation, with a DAS28-CRP at 1 week of 2.79±0.21 (P < .01). In addition, participants reported persistent improvements in visual analogue scale scores following stimulation treatment.
“Together, these studies establish that vibrotactile stimulation at the cymba concha modulates TNF, IL-6 and IL-1 [beta] production and reduces inflammation in humans,” Chavan and colleagues wrote. “These findings also demonstrate that transcutaneous vagus nerve stimulation reduces the disease severity in RA patients.”
“This pilot study supports the future development of novel non-invasive bioelectronic treatment modalities for diseases currently treated with drugs,” they added. “Clinical trials in RA are warranted to address the clinical efficacy, as our findings suggest that it is possible to use the vibrotactile taVNS in the experimental therapy of RA and possibly other cytokine-mediated auto-inflammatory disorders.” – by Jason Laday
Disclosure: The researchers report no relevant financial disclosures.