Effects of Etelcalcetide on Bone Microstructure in the Adenine-Induced Chronic Kidney Disease Rat Model

Objective: Chronic kidney disease (CKD) with secondary hyperparathyroidism (SHPT) increases the risk of fragility fractures with deterioration of cortical and trabecular bone microstructure. Etelcalcetide (EC), which is used to treat SHPT, reduces parathyroid hormone (PTH) levels in the blood. However, the details of the effects of EC on the microstructure of cortical and trabecular bone remain unclear. This study investigated whether EC improved the cortical and trabecular bone microstructure in CKD model rats. Methods: Eight-week-old, male Wistar rats were fed with a 0.75% adenine diet for 4 weeks to establish the CDK model rats. At 20 weeks of age, the rats were divided into two groups (n = 9 - 11 in each group): CKD group (vehicle administration) and EC group (0.6 mg/kg, daily). EC was injected for 4 weeks starting at 20 weeks of age. After treatment, the biochemical tests, measurement of bone mineral density and bone strength, and evaluation of cortical and trabecular bone microstructure were performed. Results: Compared with the CKD group, the EC group showed significantly lower serum blood urea nitrogen, calcium, and inorganic phosphorus levels (p p p p p Conclusions: EC significantly improved cortical microstructure and cortical porosity, suppressing deterioration of cortical bone strength and loss of trabecular bone in the adenine-induced CKD model rats.

Effects of Teriparatide and Aerobic Exercise on Lumbar Spine Microstructure in Ovariectomized and Tail-Suspended Rats

Osteoporosis is an increasingly prevalent malady of the elderly that is associated with bone fragility and increased risk of fractures. Osteoporosis treatments focus on restoring bone strength and quality. Teriparatide (TPTD) is a therapeutic agent that has been shown to increase bone strength by improving the volume and connectivity of trabecular bone. Exercise is also known to have pro-osteogenic effects. Here we used a rat model of severe osteoporosis (ovariectomized and tail-suspension) to evaluate the effects of TPTD, exercise and a combination of TPTD and exercise on the microstructure of trabecular bone. TPTD mono-therapy and TPTD combined with exercise treatment significantly increased bone mineral density (BMD) in the whole body. Micro-computed tomography analysis revealed that a combination of exercise and TPTD treatment significantly decreased bone surface to volume and trabecular separation compared with those of the control and exercise groups. Node-strut analysis indicated that exercise or TPTD alone did not affect trabecular bone connectivity. However, the combination of exercise and TPTD treatment significantly decreased measures of trabecular bone connectivity (node number) that are consistent with a transition from rod-like to plate-like of trabecular bone microstructures. The combination treatment with exercise and TPTD improved microstructure of trabecular bone in the OVX and tail-suspended rats. These results indicate that combining exercise with TPTD represents a viable means to improve cancellous bone strength in osteoporosis populations.

Coupling of plasmonic nanopore pairs: facing dipoles attract each other

Control of the optical properties of nano-plasmonic structures is essential for next-generation optical circuits and high-throughput biosensing platforms.Realization of such nano-optical devices requires optical couplings of various nanostructured elements and field confinement at the nanoscale.In particular,symmetric coupling modes,also referred to as dark modes,have recently received considerable attention because these modes can confine light energy to small spaces.Although the coupling behavior of plasmonic nanoparticles has been relatively well studied,couplings of inverse structures,that is,holes and pores,remain partially unexplored.Even for the most fundamental coupling system of two dipolar holes,comparison of the symmetric and antisymmetric coupling modes has not been performed.Here we present,for the first time,a systematic study of the symmetric and anti-symmetric coupling of nanopore pairs using cathodoluminescence by scanning transmission electron microscopy and electromagnetic simulation.The symmetric coupling mode,approximated as a pair of facing dipoles,is observed at a lower energy than that of the anti-symmetric coupling mode,indicating that the facing dipoles attract each other.The anti-symmetric coupling mode splits into the inner-and outer-edge localized modes as the coupling distance decreases.These coupling behaviors cannot be fully explained as inverses of coupled disks.Symmetric and anti-symmetric coupling modes are also observed in a short-range ordered pore array,where one pore supports multiple local resonance modes,depending on the distance to the neighboring pore.Accessibility to the observed symmetric modes by far field is also discussed,which is important for nanophotonic device applications.