Deep brain stimulation as a therapeutic option for obesity: A critical review

Goat Milk Supplementation Modulates the Mitochondrial Metabolic Flexibility and Orexin-A Levels Influencing the Inflammatory Pattern in Rats

Milk and its derivatives are included in a balanced diet of humans as excellent sources of proteins, vitamins, and essential minerals that are functional nutrients. Knowledge about the nutritional benefits or harms due to milk consumption has been expanding in recent years. We previously explored, in rodent models, the metabolic effects of isoenergetic intake of milk derived from cows, donkeys, or humans, while the impact of goat's milk intake has remained unexplored. The aim of this work was to investigate, in an animal model, the effects of dietary supplementation with goat's milk on energy homeostasis and inflammatory state, focusing on the modulation of mitochondrial functions in most metabolically active organs, such as skeletal muscle and the liver. In addition, we highlighted a link between nutrient intake, substrate metabolism, and the orexinergic system. Our results indicate that goat milk improves mitochondrial oxidative capacity and reduces inflammation and oxidative stress in both organs. Notably, goat milk lowers the circulating levels of Orexin-A, a neuropeptide that plays a crucial role in regulating peripheral energy balance and central nervous system mechanisms. These data provide the first evidence that the anti-inflammatory and antioxidant effects of goat milk are mediated by the modulation of mitochondrial functions and orexinergic signaling.

Deep Brain Stimulation for Morbid Obesity: An Underutilized Neuromodulatory Treatment for Severely Obese Patients?

Background Morbid obesity (MO) has been steadily increasing in the last few years. Pharmacotherapy and bariatric surgeries remain the main treatment modalities for MO, although in the long-term they may lose their effectiveness. Other treatment approaches are urgently needed and deep brain stimulation (DBS) is a promising therapy. Disturbed energy homeostasis caused by intake of highly palatable and caloric foods may induce hedonic eating. The brain nuclei responsible for energy homeostasis and hedonia are the hypothalamic nuclei and nucleus accumbens. These brain structures constitute the stereotactic targets approached with DBS to treat MO.

Material and Methods We have performed a literature search of all available clinical applications of DBS for MO in humans. We were able to identify three case series reports and additional six case reports involving 16 patients. The selected stereotactic targets included lateral hypothalamus in eight patients, ventromedial hypothalamus in two patients, and nucleus accumbens in six patients.

Results In general, the safety profile of DBS in refractory MO patients was good. Clinical improvement regarding the mean body mass index could be observed in obese patients.

Conclusions MO is a demanding condition. Since in some cases standardized treatment is ineffective, new therapies should be implemented. DBS is a promising therapy that might be used in patients suffering from MO, however, more studies incorporating more individuals and with a longer follow-up are needed to obtain more reliable results concerning its effectiveness and safety profile.

Stimulating the nucleus accumbens in obesity: A positron emission tomography study after deep brain stimulation in a rodent model

PURPOSE

The nucleus accumbens (NAcc) has been suggested as a possible target for deep brain stimulation (DBS) in the treatment of obesity. Our hypothesis was that NAcc-DBS would modulate brain regions related to reward and food intake regulation, consequently reducing the food intake and, finally, the weight gain. Therefore, we examined changes in brain glucose metabolism, weight gain and food intake after NAcc-DBS in a rat model of obesity.

PROCEDURES

Electrodes were bilaterally implanted in 2 groups of obese Zucker rats targeting the NAcc. One group received stimulation one hour daily during 15 days, while the other remained as control. Weight and daily consumption of food and water were everyday registered the days of stimulation, and twice per week during the following month. Positron emission tomography (PET) studies with 2-deoxy-2-[18F]fluoro-D-glucose (FDG) were performed 1 day after the end of DBS. PET data was assessed by statistical parametric mapping (SPM12) software and region of interest (ROI) analyses.

RESULTS

NAcc-DBS lead to increased metabolism in the cingulate-retrosplenial-parietal association cortices, and decreased metabolism in the NAcc, thalamic and pretectal nuclei. Furthermore, ROIs analyses confirmed these results by showing a significant striatal and thalamic hypometabolism, and a cortical hypermetabolic region. However, NAcc-DBS did not induce a decrease in either weight gain or food intake.

CONCLUSIONS

NAcc-DBS led to changes in the metabolism of regions associated with cognitive and reward systems, whose impairment has been described in obesity.