Background Hip fracture is a public health concern because of its considerable morbidity, excess mortality, great risk of disability, and high societal healthcare costs. China has the largest population of older people in the world and is experiencing rapid population aging and facing great challenges from an increasing number of hip fractures. However, few studies reported the epidemiology, especially at a national level. We aimed to evaluate trends in hip fracture incidence and associated costs for hospitalization in China. Methods and findings We conducted a population-based study using data between 2012 and 2016 from the national databases of Urban Employee Basic Medical Insurance and Urban Resident Basic Medical Insurance in China, covering about 480 million residents. Data from around 102.56 million participants aged 55 years and older during the study period were analyzed. A total of 190,560 incident hip fracture patients (mean age 77.05 years, standard deviation 8.94; 63.99% female) were identified. Primary outcomes included the age-and sex-specific incidences of hip fracture. Associated annual costs for hospitalization were also calculated. Incidence was described as per 100,000 person-years at risk, and 95% confidence intervals were computed assuming a Poisson distribution. Hip fracture incidence overall in China did not increase during the study period despite rapid population aging. Incidence per 100,000

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To investigate roles for bone marrow adipocyte (BMAd) lipolysis in bone homeostasis, we created a BMAd-specific Cre mouse model in which we knocked out adipose triglyceride lipase (ATGL, Pnpla2 gene). BMAd-Pnpla2-/- mice have impaired BMAd lipolysis, and increased size and number of BMAds at baseline. Although energy from BMAd lipid stores is largely dispensable when mice are fed ad libitum, BMAd lipolysis is necessary to maintain myelopoiesis and bone mass under caloric restriction. BMAd-specific Pnpla2 deficiency compounds the effects of caloric restriction on loss of trabecular bone in male mice, likely due to impaired osteoblast expression of collagen genes and reduced osteoid synthesis. RNA sequencing analysis of bone marrow adipose tissue reveals that caloric restriction induces dramatic elevations in extracellular matrix organization and skeletal development genes, and energy from BMAd is required for these adaptations. BMAd-derived energy supply is also required for bone regeneration upon injury, and maintenance of bone mass with cold exposure.

Sustainable release of simvastatin from poloxamer 407 hydrogel in 3D-printed porous Ti6Al4V for spinal fusion in rhesus macaques.

Poly(N-isopropylacrylamide) (PNIPAM) based electrically conductive hydrogels (PNIPAM-ECHs) have been extensively studied in recent decades due to their thermal-responsive (leading to the volume change of hydrogels) and electrically conductive performance. The incorporation of conductive components into the PNIPAM hydrogel network makes it become conductive hydrogel, and as a result, the PNIPAM hydrogel could become sensitive to an electrical signal, greatly expanding its application. In addition, conductive components usually bring new stimuli-responsive properties of PNIPAM-based hydrogels, such as near-infrared light and stress/strain responsive properties. PNIPAM-ECHs display a wide range of applications in human motion detection, actuators, controlled drug release, wound dressings, etc. To summarize recent research advances and achievements related to PNIPAM-ECHs, this manuscript first reviews the design and structure of representative PNIPAM-ECHs according to their conductive components. Then, the applications of PNIPAM-ECHs have been classified and discussed. Finally, the remaining problems related to PNIPAM-ECHs have been summarized and a future research direction is proposed which is to fabricate PNIPAM-ECHs with integrated multifunctionality.

Simvastatin is a translational drug that may be used to induce local bone formation. In this study, simvastatin microcrystals were made by a wet media milling method, and then we verified the osteogenic effect of the microcrystals in rat ovariectomy (OVX)–induced osteoporosis and femur defect models. For the osteoporosis model, we delivered simvastatin microcrystals to the tibia with poloxamer hydrogels via an intraosseous injection. Bone mineral density and the ultimate force of the treated tibia were significantly improved after injection of simvastatin microcrystals at 0.5 and 1 mg compared with the OVX or 0‐mg control groups. For the femur defect model, simvastatin microcrystals were incorporated in clinically used calcium phosphate cements (CPCs) as an implant. Quantitative analysis of bone regeneration by microcomputed tomography (μCT) showed improved bone morphology with simvastatin microcrystals at 50 and 100 μg, compared with the CPC vehicle. A semiquantitative scale for histology assessment further demonstrated a higher bone regeneration score in the drug‐loaded groups. Our study shows that simvastatin microcrystals can promote bone formation by local delivery using a poloxamer hydrogel or CPC, which may be translationally useful.

Background: This study explored the effect of a single local intraosseous application of a small dose of simvastatin on the wound healing process in type 1 diabetic rats and related mechanisms. Methods: The authors chose the streptozotocin-induced type 1 diabetic rat to establish a full-thickness dermal wound using a 12-mm-diameter sterile disposable punch. The rats (n = 32) were divided randomly into four groups: (1) normal control rats, (2) type 1 diabetic rats with intraosseous injection of hydrogel vehicle, (3) type 1 diabetic rats with intraosseous injection of simvastatin (0.5 mg), and (4) type 1 diabetic rats with intragastric administration of simvastatin (20 mg/kg per day). Wound closure was followed by digital planimetry. Mobilization of endothelial progenitor cells into the circulatory system was studied using fluorescence-activated cell sorting. Neovascularization was analyzed with immunofluorescence histochemical staining. The relative levels of adiponectin and stromal cell-derived factor 1 (SDF-1) in serum, bone, and wound tissues were examined by enzyme-linked immunosorbent assay and Western blot. Results: Diabetic rats exhibited impaired wound healing. Intraosseous administration of simvastatin accelerated wound healing beginning at day 4, and angiogenesis was more obvious than in the control group. Enzyme-linked immunosorbent assay revealed that adiponectin concentrations in the diabetic rats with intraosseous injection of hydrogel vehicle plus simvastatin 0.5-mg group were significantly higher compared with the diabetic rats with intraosseous injection of hydrogel vehicle group beginning at day 4. Intraosseous administration of simvastatin decreased the expression of adiponectin and SDF-1 in bone tissue but enhanced the expression of adiponectin in wounded skin. Conclusions: A single local intraosseous application of simvastatin promotes wound healing in type 1 diabetic rat. The underlying mechanisms may be attributed to the regulation of the adiponectin/SDF-1 pathway, which plays a pivotal role in endothelial progenitor cell mobilization and angiogenesis.

Bone marrow adipocytes (BMAd) are a unique cell population derived from bone marrow mesenchymal progenitors and marrow adipogenic lineage precursors. Although they have long been considered to be a space-filler within bone cavities, recent studies have revealed important physiological roles in hematopoiesis and bone metabolism. To date, the approaches used to study BMAd function have been confounded by contributions by non-marrow adipocytes or by bone marrow stromal cells. To address this gap in the field, we have developed a BMAdspecific Cre mouse model to deplete BMAds by expression of diphtheria toxin A (DTA), or by deletion of peroxisome proliferator-activated receptor gamma (Pparg). We found that DTAinduced loss of BMAds results in decreased hematopoietic stem and progenitor cell numbers and increased bone mass in BMAd-enriched locations, including the distal tibiae and caudal vertebrae. Elevated bone mass appears to be secondary to enhanced endosteal bone formation, suggesting a local effect caused by depletion of BMAd. Augmented bone formation with BMAd-depletion protects mice from bone loss induced by caloric restriction or ovariectomy, and facilitates the bone healing process after fracture. Finally, ablation of Pparg also reduces BMAd numbers and largely recapitulates high bone mass phenotypes observed with DTAinduced BMAd depletion.