Gray matter volume increases induced by intragastric balloon treatment and their associations with neuroinflammation: A magnetic resonance study

•Intra-gastric balloon treatment led to brain structural improvements.•They are consistent with pattern observed in bariatric patients.•Structural recovery observed in regions earlier related to diabetes and hypertension.•These changes are related to normalziation of in brain myo-inositol, a marker of neuroinflammation, We simultaneously performed structural MRI, 1H magnetic resonance spectroscopy, and whole-body hydration status assessment to evaluate brain changes in patients with morbid obesity treated with intra-gastric balloon (IGB) for six months. We asked, if changes in myo-inositol ratios (marker of neuroinflammation) are related to brain volume increases accompanying IGB-induced weight loss. Twenty five patients with morbid obesity (OB, 43.9 ± 11.8 years, BMI = 49.1 ± 7.2, 12 females, 9 without co-morbid conditions) were treated with IGB for six months. They underwent magnetic resonance imaging at 3T one month before IGB insertion, three months after insertion (N = 19), and one month after IGB removal (N = 14). Insertion of IGB lead to 8.9% and 12.3% weight reduction over the first three months and over the entire treatment, respectively. Over the entire treatment, total gray matter volume increased by 2.0% (p = 0.009). These changes were mostly pronounced in the left precuneus and in the right frontal pole (>1.9%, p < 0.009). The increases in cortical volume in the right hemisphere and the left posterior cingulate cortical thickness over the entire treatment were significantly related to decreases in myo-inositol ratios measured over the first three months of the treatment (r < −0.740, p < 0.006). IGB treatment lead to brain structural improvements consistent with earlier studies of bariatric patients without co-morbid conditions. Our results also pointed to improvements in brain regions, where atrophy in other studies was related to type 2 diabetes and hypertension. The correlations point to neuroinflammation as one of the potential processes behind brain volume reductions in patients with morbid obesity.