Gel stent versus trabeculectomy: The randomized, multicenter, Gold-Standard Pathway Study (GPS) of effectiveness and safety at 12 months

PURPOSE: To compare effectiveness and safety of the gel stent to trabeculectomy in open-angle glaucoma (OAG). DESIGN: Prospective, randomized, multicenter, noninferiority study. METHODS: Patients with OAG and intraocular pressure (IOP) 15 to 44 mm Hg on topical IOP-lowering medication were randomized 2:1 to gel stent implantation or trabeculectomy. Primary end point (surgical success): percentage of patients at month 12 achieving ≥20% IOP reduction from baseline without medication increase, clinical hypotony, vision loss to counting fingers, or secondary surgical intervention (SSI) in a noninferiority test with 24% margins. Secondary end points (month 12) included mean IOP and medication count, postoperative intervention rate, visual recovery, and patient-reported outcomes (PROs). Safety end points included adverse events (AEs). RESULTS: At month 12, the gel stent was statistically noninferior to trabeculectomy (between-treatment difference [Δ], -6.1%; 95% CI, -22.9%, 10.8%); 62.1% and 68.2% achieved the primary end point, respectively (P=.487); mean IOP and medication count reductions from baseline were significant (P\u3c.001); and the IOP change-related Δ (2.8 mm Hg) favored trabeculectomy (P=.024). The gel stent resulted in fewer eyes requiring in-office postoperative interventions (P=.024 after excluding laser suture lysis), faster visual recovery (P≤.048), and greater 6-month improvements in visual function problems (ie, PROs; P≤.022). The most common AEs were reduced visual acuity at any time (gel stent, 38.9%; trabeculectomy, 54.5%) and hypotony (IOP \u3c6 mm Hg at any time) (gel stent, 23.2%; trabeculectomy, 50.0%). CONCLUSIONS: At month 12, the gel stent was statistically noninferior to trabeculectomy, per the percentage of patients achieving ≥20% IOP reduction from baseline without medication increase, clinical hypotony, vision loss to counting fingers, or SSI. Trabeculectomy achieved a statistically lower mean IOP, numerically lower failure rate, and numerically lower need for supplemental medications. The gel stent resulted in fewer postoperative interventions, better visual recovery, and fewer AEs

Conformational Basis for Asymmetric Seeding Barrier in Filaments of Three- and Four-Repeat Tau

*S Supporting Information ABSTRACT: Tau pathology in Alzheimer’s disease is intimately linked to the deposition of proteinacious filaments, which akin to infectious prions, have been proposed to spread via seeded conversion. Here we use double electron−electron resonance (DEER) spectroscopy in combination with extensive computational analysis to show that filaments of three- (3R) and four-repeat (4R) tau are conformationally distinct. Distance measurements between spin labels in the third repeat, reveal tau amyloid filaments as ensembles of known β-strand−turn−β-strand U-turn motifs. Whereas filaments seeded with 3R tau are structurally homogeneous, filaments seeded with 4R tau are heterogeneous, composed of at least three distinct conformers. These findings establish a molecular basis for the seeding barrier between different tau isoforms and offer a new powerful approach for investigating the composition and dynamics of amyloid fibril ensembles

Cryo-EM structure of islet amyloid polypeptide fibrils reveals similarities with amyloid-β fibrils

Amyloid deposits consisting of fibrillar islet amyloid polypeptide (IAPP) in pancreatic islets are associated with beta-cell loss and have been implicated in type 2 diabetes (T2D). Here, we applied cryo-EM to reconstruct densities of three dominant IAPP fibril polymorphs, formed in vitro from synthetic human IAPP. An atomic model of the main polymorph, built from a density map of 4.2-Å resolution, reveals two S-shaped, intertwined protofilaments. The segment 21-NNFGAIL-27, essential for IAPP amyloidogenicity, forms the protofilament interface together with Tyr37 and the amidated C terminus. The S-fold resembles polymorphs of Alzheimer's disease (AD)-associated amyloid-β (Aβ) fibrils, which might account for the epidemiological link between T2D and AD and reports on IAPP-Aβ cross-seeding in vivo. The results structurally link the early-onset T2D IAPP genetic polymorphism (encoding Ser20Gly) with the AD Arctic mutation (Glu22Gly) of Aβ and support the design of inhibitors and imaging probes for IAPP fibrils

Cryo-EM structure and inhibitor design of human IAPP (amylin) fibrils

Human islet amyloid polypeptide (hIAPP) functions as a glucose-regulating hormone but deposits as amyloid fibrils in more than 90% of patients with type II diabetes (T2D). Here we report the cryo-EM structure of recombinant full-length hIAPP fibrils. The fibril is composed of two symmetrically related protofilaments with ordered residues 14-37. Our hIAPP fibril structure (i) supports the previous hypothesis that residues 20-29 constitute the core of the hIAPP amyloid; (ii) suggests a molecular mechanism for the action of the hIAPP hereditary mutation S20G; (iii) explains why the six residue substitutions in rodent IAPP prevent aggregation; and (iv) suggests regions responsible for the observed hIAPP cross-seeding with β-amyloid. Furthermore, we performed structure-based inhibitor design to generate potential hIAPP aggregation inhibitors. Four of the designed peptides delay hIAPP aggregation in vitro, providing a starting point for the development of T2D therapeutics and proof of concept that the capping strategy can be used on full-length cryo-EM fibril structures