Curcumin nanoemulsions stabilized by whey protein isolate were successfully developed using high-pressure homogenization. The effect of a chitosan layer deposition using the layer-by-layer technique on nanoemulsions' stability was evaluated during storage conditions, as well as during gastrointestinal tract passage. Lipids' hydrolysis and curcumin bioaccessibility was assessed using a dynamic gastrointestinal model (simulating the stomach, duodenum, jejunum and ileum) and the cytotoxicity, cellular antioxidant activity and permeability analyses were carried out using Caco-2 cells. Results showed that both nanosystems were stable during one month of storage and at stomach pH conditions, whereas creaming and phase separation occurred at intestine pH conditions. The addition of a chitosan layer increased curcumin bioaccessibility, whereas cellular antioxidant activity studies revealed that nanoemulsions and multilayer nanoemulsions exhibited 9 and 10 times higher antioxidant capacity at the cellular level, respectively, when compared to free curcumin. Permeability assays showed that the use of a chitosan layer significantly increased the apparent permeability coefficient of curcumin through Caco-2 cells by 1.55-folds.
Background: The cause of frequent falls in patients with Alzheimer's disease (AD) is still not well understood. Nevertheless, balance control and sensory organization are known to be critical for moving safely and adapting to the environment. Methods: We evaluated postural stability in 20 AD patients (11 fallers and 9 nonfallers) and 16 healthy controls with an inertial measurement unit (triaxial accelerometers and gyroscopes) attached to the center of mass (COM) in different balance conditions (Romberg on flat surface and frontward/backward-inclined surface, with or without visual suppression) in a motor lab. Results: In AD patients, the group of fallers showed a different kinetic pattern of postural stability characterized by higher vulnerability to visual suppression, higher total/maximal displacement and a mediolateral/anteroposterior range of sway, and a consequent need for more corrections of COM pitch and roll angles. Conclusion: Further studies are needed to consolidate the normative values of the discriminatory kinetic variables with the potential of inclusion in a multifactorial analysis of the risk of falls. Nevertheless, these results highlight signs of impairment of central postural control in AD, which may require early therapeutic intervention.
Quantitative postural sway evaluation is useful in the investigation of Parkinsonian syndromes. VPD patients have higher AP postural sway that is correlated with their gait disturbance burden and also not responsive to levodopa. These observations corroborate the interconnection of postural control and locomotor networks.
Background/Aims: Alzheimer's disease (AD) patients have an impaired ability to quickly reweight central sensory dependence in response to unexpected body perturbations. Herein, we aim to study provoked compensatory postural adjustments (CPAs) in a conflicting sensory paradigm with unpredictable visual displacements using virtual reality goggles. Methods: We used kinematic time-frequency analyses of two frequency bands: a low-frequency band (LB; 0.3-1.5 Hz; mechanical strategy) and a high-frequency band (HB; 1.5-3.5 Hz; cognitive strategy). We enrolled 19 healthy subjects (controls) and 21 AD patients, divided according to their previous history of falls. Results: The AD faller group presented higher-power LB CPAs, reflecting their worse inherent postural stability. The AD patients had a time lag in their HB CPA reaction. Conclusion: The slower reaction by CPA in AD may be a reflection of different cognitive resources including body schema self-perception, visual motion, depth perception, or a different state of fear and/or anxiety.
Nanoemulsions can be used to improve the bioaccessibility of lipophilic bioactive compounds, such as curcumin, being their behaviour highly influenced by their interfacial properties. The effect of chitosan and alginate layers' deposition on curcumin nanoemulsions' behaviour during in vitro digestion was evaluated using a dynamic gastrointestinal system. Results showed that polyelectrolyte layers' deposition improved curcumin antioxidant capacity during in vitro digestion. In addition, multilayer nanoemulsions showed a better control of the rate and extent of lipid digestibility by decreasing free fatty acids release, compared to uncoated nanoemulsions. However, a lower curcumin bioaccessibility was observed for multilayer nanoemulsions. Although cytotoxicity assays revealed that both nanosystems are toxic due to the use of sodium dodecyl sulphate (SDS), nanosystems were 3.3-fold less toxic than SDS itself.This study showed that multilayer nanoemulsions could be used to increase satiety by retarding lipid digestion, which can be important for functional foods development for combating obesity.
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