Polygenic Risk Scores in a Prospective Parkinson's Disease Cohort.

BACKGROUND: Ethnic-specific genetic risk assessment framework for Parkinson's disease (PD) is lacking for the Asian population. OBJECTIVE: We investigated the association of a polygenic risk score (PRS) with PD incidence in a population-based Asian prospective cohort. METHODS: Genetic, dietary, and lifestyle information were prospectively collected from 25,646 participants within the Singapore Chinese Health Study cohort. PRS was constructed with Asian-specific and top genome-wide association study variants. The association between PRS and PD incidence was evaluated with multivariable Cox proportional hazard models, Kaplan-Meier survival analysis, and concordance statistics. RESULTS: A total of 333 incident cases were identified after a follow-up period of more than 20 years. Participants with PRS in the top tertile (hazard ratio [HR], 1.81; 95% confidence interval [CI], 1.37-2.39) and middle tertile (HR, 1.35; 95% CI, 1.00-1.83) are at higher risk of developing PD after adjusting for dietary and lifestyle risk factors, with a shorter time to PD event in a Kaplan-Meier survival analysis (P < 0.001). CONCLUSION: We identified a PRS that was significantly associated with PD incidence in a prospective Chinese cohort after adjusting for dietary and lifestyle factors. © 2021 International Parkinson and Movement Disorder Society.

3D Freeform Printing of Nanocomposite Hydrogels through in situ Precipitation in Reactive Viscous Fluid.

Composite hydrogels have gained great attention as three-dimensional (3D) printing biomaterials because of their enhanced intrinsic mechanical strength and bioactivity compared to pure hydrogels. In most conventional printing methods for composite hydrogels, particles are preloaded in ink before printing, which often reduces the printability of composite ink with little mechanical improvement due to poor particle-hydrogel interaction of physical mixing. In contrast, the in situ incorporation of nanoparticles into a hydrogel during 3D printing achieves uniform distribution of particles with remarkable mechanical reinforcement, while precursors dissolved in inks do not influence the printing process. Herein, we introduced a "printing in liquid" technique coupled with a hybridization process, which allows 3D freeform printing of nanoparticle-reinforced composite hydrogels. A viscoplastic matrix for this printing system provides not only support for printed hydrogel filaments but also chemical reactants to induce various reactions in printed objects for in situ modification. Nanocomposite hydrogel scaffolds were successfully fabricated through this 3D freeform printing of hyaluronic acid (HAc)-alginate (Alg) hydrogel inks through a two-step crosslinking strategy. The first ionic crosslinking of Alg provided structural stability during printing, while the secondary crosslinking of photo-curable HAc improved the mechanical and physiological stability of the nanocomposite hydrogels. For in situ precipitation during 3D printing, phosphate ions were dissolved in the hydrogel ink and calcium ions were added to the viscoplastic matrix. The composite hydrogels demonstrated a significant improvement in mechanical strength, biostability, as well as biological performance compared to pure HAc. Moreover, the multi-material printing of composites with different calcium phosphate contents was achieved by adjusting the ionic concentration of inks. Our method greatly accelerates the 3D printing of various functional or hybridized materials with complex geometries through the design and modification of printing materials coupled with in situ post-printing functionalization and hybridization in reactive viscoplastic matrices.