Deep TMS cuts food cravings in obese patients via neuroendocrine modulation

A single session of noninvasive deep transcranial magnetic stimulation (dTMS) can curb appetite and promote satiety in obese individuals, according to new data. One 30-minute session of high-frequency dTMS significantly increased blood levels of beta-endorphins compared with low-frequency dTMS and controls who did not receive dTMS, reported Italian researchers at the 20^th European Congress of Endocrinology held in Barcelona.  

“For the first time, this study is able to suggest an explanation of how dTMS could alter food cravings in obese subjects,” said lead investigator Professor Livio Luzi, University of Milan, Italy. “Given the distressing effects of obesity in patients, and the socioeconomic burden of the condition, it is increasingly urgent to identify new strategies to counteract the current obesity trends. dTMS could present a much safer and cheaper alternative to treat obesity compared to drugs or surgery.”

dTMS stimulates neurons in specific neural areas and is used to treat depression and addictive behaviors. Previous studies suggest that this modality may also be a good option in reducing drug and food cravings.

The investigators assigned 40 obese patients (mean age: 48.0 years; mean BMI: 36.3) to receive one session of high frequency (18 Hz), low frequency (1 Hz), or sham stimulation targeted to the prefrontal cortex and insula, bilaterally.

Following the 18 Hz dTMS session, levels of norepinephrine were significantly increased by 18.0% (P=0.01) and levels of β-endorphins by 13.9% (P=0.017) compared with the sham arm. High-frequency dTMS was also significantly superior to low-frequency dTMS on these endpoints (P=0.05 and P=0.010, respectively). The high-frequency group also experienced a significant increase in glucose levels versus the sham group (7.0%; P=0.002).

In addition, researchers observed significant decreases in levels of leptin (-16.3%: P=0.002) and pituitary hormones, specifically thyroid stimulating hormone (-20.7%: P=0.001) and prolactin (-34.7%: P < 0.0001) after a single 18 Hz dTMS session compared with sham.

In the arm receiving low-frequency tDMS, a significant reduction of salivary cortisol was also observed (-29.4%; P=0.015).

“These results suggest that dTMS can acutely affect orexygenic pathways and metabolic parameters mainly via modulation of the sympathetic activity and hypothalamic-pituitary-adrenal axis,” the researchers concluded. “The increase of β-endorphins could suggest a potential role of high frequency dTMS in inducing the dopaminergic system activation and therefore, in modulating the food reward system. Together these findings support the role of dTMS as a novel promising treatment for obesity.”

Other data from the same researchers show that dTMS changed the composition of gut microbiota of obese individuals, which may also partially explain the weight loss associated with dTMS. At the 2017 meeting of the Endocrine Society’s 99^th Annual Meeting, they presented data from a study of 14 obese subjects (mean age: 45.4 years; mean BMI: 38.3) who received dTMS or sham sessions 3 times per week for 5 weeks, for a total of 15 sessions. At baseline and at the end of treatment, stool samples were collected for microbiota analysis.

After 5 weeks, subjects lost a mean of 3.1% of body weight (P < 0.01) and 4.2% of fat mass (P < 0.05) compared with sham controls (associated with a significant decrease in insulin levels), and increased their abundance of Faecalibacterium by 66% and Phascolarctobacterium by 23% in their stool samples compared with baseline.