Impact of Nutrition,Microbiota Transplant and Weight Loss Surgery on Dopaminergic Alterations in Parkinson’s Disease and Obesity

Parkinson’s disease (PD), the second most common neurodegenerative disorder worldwide, is characterized by dopaminergic neuron degeneration and α-synuclein aggregation in the substantia nigra pars compacta of the midbrain. Emerging evidence has shown that dietary intake affects the microbial composition in the gut, which in turn contributes to, or protects against, the degeneration of dopaminergic neurons in affected regions of the brain. More specifically, the Mediterranean diet and Western diet, composed of varying amounts of proteins, carbohydrates, and fats, exert contrasting effects on PD pathophysiology via alterations in the gut microbiota and dopamine levels. Interestingly, the negative changes in the gut microbiota of patients with PD parallel changes that are seen in individuals that consume a Western diet, and are opposite to those that adhere to a Mediterranean diet. In this review, we first examine the role of prominent food groups on dopamine bioavailability, how they modulate the composition and function of the gut microbiota and the subsequent effects on PD and obesity pathophysiology. We then highlight evidence on how microbiota transplant and weight loss surgery can be used as therapeutic tools to restore dopaminergic deficits through optimizing gut microbial composition. In the process, we revisit dietary metabolites and their role in therapeutic approaches involving dopaminergic pathways. Overall, understanding the role of nutrition on dopamine bioavailability and gut microbiota in dopamine-related pathologies such as PD will help develop more precise therapeutic targets to rescue dopaminergic deficits in neurologic and metabolic disorders.     

Wet Milling of Alginate Alco- and Hydrogel Composites: A Facile Top-Down Approach for Continuous Production of Aerogel Microparticles

Moving toward high-throughput production of biopolymer aerogel microparticles, in this work, the wet milling process is applied to hydrogels and alcogels. Alcogels are then converted into aerogels by well-established supercritical drying. Alginate and hybrid alginate/silica gels are used as a model system. As the Young's moduli of hydrogels significantly change when water is exchanged by ethanol, it is possible to study the effect of the gel stiffness on macroscopic and microstructural properties of the resulting aerogels. Influence of process parameters (milling speed and gap size) is also investigated. Smallest particles sizes and minimal changes in microstructure are obtained for completely solvent exchanged gels. The wet milling is shown to be a versatile method to obtain aerogel particles with diameters in the range 50–300 µm.