Palmitate Is Increased in the Cerebrospinal Fluid of Humans with Obesity and Induces Memory Impairment in Mice via Pro-inflammatory TNF-α.

Obesity has been associated with cognitive decline, atrophy of brain regions related to learning and memory, and higher risk of developing dementia. However, the molecular mechanisms underlying these neurological alterations are still largely unknown. Here, we investigate the effects of palmitate, a saturated fatty acid present at high amounts in fat-rich diets, in the brain. Palmitate is increased in the cerebrospinal fluid (CSF) of overweight and obese patients with amnestic mild cognitive impairment. In mice, intracerebroventricular infusion of palmitate impairs synaptic plasticity and memory. Palmitate induces astroglial and microglial activation in the mouse hippocampus, and its deleterious impact is mediated by microglia-derived tumor necrosis factor alpha (TNF-α) signaling. Our results establish that obesity is associated with increases in CSF palmitate. By defining a pro-inflammatory mechanism by which abnormal levels of palmitate in the brain impair memory, the results further suggest that anti-inflammatory strategies may attenuate memory impairment in obesity.

Cellulose nanowhiskers improve the methylene blue adsorption capacity of chitosan-g-poly(acrylic acid) hydrogel.

Cellulose nanowhiskers (CNWs, 90% crystalline) were used to enhance the adsorption capacity of chitosan-g-poly(acrylic acid) hydrogel. The composites up to 20w/w-% CNWs showed improved adsorption capacity towards methylene blue (MB) as compared to the pristine hydrogel. At 5w/w-% CNWs the composite presented the highest adsorption capacity (1968mg/g). The maximum removal of MB (>98% of initial concentration 2000mg/L) was achieved quickly (60min) at room temperature, pH 6, and at low ionic strength (0.1M). Adsorption mechanism was explained with the Langmuir type I model suggesting the formation of a MB monolayer on the adsorbent surface. The interaction between the adsorbent and MB molecules was explained by chemisorption, as suggested by the pseudo-second-order kinetic model. Desorption experiments showed that 75% of loaded-MB could be recovered from the adsorbent by its immersion in a pH 1 solution. Additional experiments showed the post-utilized composite could be regenerated and reused for at least 5 consecutive adsorption/desorption cycles with minimum efficiency loss (∼2%).