Sappanone a alleviates osteoarthritis progression by inhibiting chondrocyte ferroptosis via activating the SIRT1/Nrf2 signaling pathway.

Osteoarthritis (OA) is a common degenerative joint disease that cause pain and disability in adults. Chondrocyte ferroptosis is found to be involved in OA progression. Sappanone A has been found as an anti-inflammatory and antioxidative agent in several diseases.

Tumour necrosis factor α regulates the miR-27a-3p-Sfrp1 axis in a mouse model of osteoporosis.

Osteoporosis is a metabolic bone disease that involves gradual loss of bone density and mass, thus resulting in increased fragility and risk of fracture. Inflammatory cytokines, such as tumour necrosis factor α (TNF-α), inhibit osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs), and several microRNAs are implicated in osteoporosis development. This study aimed to explore the correlation between TNF-α treatment and miR-27a-3p expression in BMSC osteogenesis and further understand their roles in osteoporosis.

PUD@HA/PEEK Scaffold Induces Subchondral Bone Regeneration to Repair Osteochondral Defect in Rabbits.

Osteochondral defects (OCDs) pose a significant challenge in clinical practice, and recent advancements in their repair indicate that satisfying subchondral bone repair may be critical for this. Herein, a series of hydroxyapatite/poly(ether ether ketone) (HA/PEEK) scaffolds were fabricated with varying mass percentages (0, 20, 30, and 40%) to induce subchondral bone regeneration. Subsequently, an optimal scaffold with 40% HA/PEEK was selected to establish osteochondral scaffolds with poly(ether urethane) urea-Danshensu (PUD) for repairing the OCD.

Ultraviolet Light Responsive N-Nitroso Polymers for Antibacterial Nitric Oxide Delivery.

This study investigates the incorporation of active secondary amine moieties into the polymer backbone by co-polymerizing 2,4,6-tris(chloromethyl)-mesitylene with three diamines, namely 1,4-diaminobutane, m-phenylenediamine, and p-phenylenediamine. This process results in the stabilization of the amine moieties and the subsequently introduced nitroso groups. Charging bioactive nitric oxide (NO) into the polymers is accomplished by converting the amine moieties into N-nitroso groups.

Direct detection and identification of periprosthetic joint infection pathogens by metagenomic next-generation sequencing.

This study assessed the application of metagenomic next-generation sequencing in pathogen detection of periprosthetic joint infections. A total of 95 cases who previously had undergone hip and knee replacement undergoing revision from January 2018 to January 2021 were included in this study. Specimens of synovial fluid and deep-tissue were collected for culture and metagenomic next-generation sequencing, and patients were retrospectively categorized as infected or aseptic using the Musculoskeletal Infection Society criteria after revision surgery.

Carbon and Iron Uptake by Phytoplankton in the Amundsen Sea, Antarctica.

Freshwater components in the Southern Ocean, whether sea ice meltwater or meteoric water, influence the growth of phytoplankton by affecting water stability and supplying dissolved iron (DFe). In addition, melting sea ice stimulates phytoplankton blooms by providing ice algae. In this study, sea ice meltwater and meteoric water in the Amundsen Sea (AS) were differentiated by their stable oxygen isotopic compositions (δO), while the phytoplankton carbon fixation rate (CFR) and iron uptake rate (FeUR) values were determined using the C and Fe tracer assays, respectively.

Sappanone A Alleviated IL-1-Induced Inflammation in OA Chondrocytes through Modulating the NF-B and Nrf2/HO-1 Pathways.

Objective: This study was to examine the anti-inflammatory effect of sappanone A on interleukin- (IL-) 1-stimulated osteoarthritis (OA) chondrocytes.

Methods: Chondrocytes were pretreated with sappanone A for 2 h before subsequent IL-1 stimulation. The mRNA expression levels of iNOs, COX-2, aggrecan, and collagen-II were measured with qRT-PCR.

Implementation of Photosensitive, Injectable, Interpenetrating, and Kartogenin-Modified GELMA/PEDGA Biomimetic Scaffolds to Restore Cartilage Integrity in a Full-Thickness Osteochondral Defect Model.

Cartilage defects caused by mechanical tear and wear are challenging clinical problems. Articular cartilage has unique load-bearing properties and limited self-repair ability. The current treatment methods, such as microfractures and autogenous cartilage transplantation to repair full-thickness cartilage defects, have apparent limitations.

Dual isotopes of nitrite in the Amundsen Sea in summer.

Nitrite (NO) is a key intermediate in the nitrogen (N) cycle, and its transformation is accomplished by microbial communities. However, due to few studies on the nitrite cycle, a clear assessment of the contribution to the marine biogeochemical cycle is missing. Here, we present data on nitrogen and oxygen isotopic composition of NO in the Amundsen Sea in summer, and explore the biogeochemical processes that influence the NO cycle.

The biological uptake of dissolved iron in the changing Daya Bay, South China Sea: Effect of pH and DO.

The oceanic acidification and coastal hypoxia have potential to enhance biological uptake of dissolved iron (Fe) by phytoplankton. In this study, the Fe uptake rate (FeUR) in Daya Bay was significantly negatively correlated with pH and dissolved oxygen (DO) (r = -0.81 and -0.

Sonic Hedgehog Induces Mesenchymal Stromal Cell Senescence-Associated Secretory Phenotype and Chondrocyte Apoptosis in Human Osteoarthritic Cartilage.

Hedgehog (HH) signaling plays a critical role in osteoarthritis (OA) pathogenesis, but the molecular mechanism remains to be elucidated. We show here that Sonic Hedgehog () gene expression is initiated in human normal cartilage stromal cells (NCSC) and increased in OA cartilage mesenchymal stromal cells (OA-MSCs) during aging. Manifesting a reciprocal cellular distribution pattern, the SHH receptors and and transcription factors and are expressed by chondrocytes (OAC) in OA cartilage.

An Imaging Measurement Study of Normal Knee Parameters in Southeast China.

Background: Imaging measurement of distal femur and proximal tibia has been the hot point in the research of total knee arthroplasty and prosthesis development, which is an important treatment for patients with advanced knee joint disease. This study retrospectively investigated the digital imaging measurement of normal knee parameters in southeast China and evaluated their clinical value.

Methods: From February 2010 to May 2014, and in accordance with the inclusion criteria, a total of 677 knees (334 female knees and 343 male knees) were categorized into 3 age groups.

Semi-enclosed bays serve as hotspots for black carbon burial: A case study in Jiaozhou Bay, western Yellow Sea.

The provenance of black carbon (BC) and its role in affecting contaminant cycling in both the atmosphere and aquatic environments have been extensively studied. However, the fate and cycling dynamics of BC, particularly in marine environments, are poorly understood. Herein, soot BC was determined in the semi-enclosed Jiaozhou Bay to examine the seasonal variability, residence timescale in seawater, and settling flux to sediments, together with particle-reactive Th.

Microalloying Design of Biodegradable Mg-2Zn-0.05Ca Promises Improved Bone-Implant Applications.

Mg and its alloys have been comprehensively studied and show huge potential for clinical orthopedic applications. However, balancing the mechanical strength and corrosion resistance of alloys is still a challenge. In light of this, micro-level contents of Zn and Ca were added to pure Mg to fabricate a Mg-2Zn-0.

Association of HSS score and mechanical alignment after primary TKA of patients suffering from constitutional varus knee that caused by combined deformities: a retrospective study.

For pre-operative osteoarthritis (OA) patients with varus knee, previous studies showed inconsistent results. Therefore, we conducted this study to better identify the association of Hospital for Special Surgery (HSS) score and mechanical alignment. 44 patients (51 knees) with constitutional varus knee caused by combined deformities (LDFA (lateral distal femoral angle) > 90°and MPTA (medial proximal tibial angle) < 85°)) were selected and analyzed with a mean follow-up period of 14 months after total knee arthroplasty (TKA).

Evaluation of a rabbit model of adjacent intervertebral disc degeneration after fixation and fusion and maintenance in an upright feeding cage.

To establish an animal model of adjacent intervertebral disc degeneration by performing spinal fixation and fusion after percutaneous needle puncture and removal of the intervertebral disc or percutaneous needling of the vertebral body without removal of the intervertebral disc.  We established a model of adjacent intervertebral disc degeneration after spinal fixation and fusion of rabbits maintained in upright feeding cages. Twenty-five healthy New Zealand rabbits were used.

Netrin-1 regulates ERK1/2 signaling pathway and autophagy activation in wear particle-induced osteoclastogenesis.

Background: Artificial joint replacement surgery is often accompanied by osteolysis induced aseptic loosening around the prosthesis. Wear particles from joint replacement are thought to be one of the main factors leading to local inflammation and osteolysis at the prosthesis site. The aim of this study was to investigate the molecular mechanism of osteoclast formation and dissolution induced by wear particles and the potential roles of Netrin-1, the ERK1/2 pathway and autophagy activation in this process.

A persistent increase in primary productivity east off Hainan Island (northwestern South China Sea) over the last decades as inferred from sediment records.

Sediment cores were analyzed from the continental shelf of the northwestern South China Sea aiming to understand the change history of primary productivity and provide insights into key changes of environmental conditions in this region over the past ~100 years. Multiple proxies including stable carbon isotopic composition (δC) of sedimentary organic matter, diatom abundance and biogenic silica burial flux were applied along with Pb chronology. Notably, these independent evidences consistently point to a steady increase of primary production in this region only after ~1960s.

Inhibition of cellular communication network factor 1 (CCN1)-driven senescence slows down cartilage inflammaging and osteoarthritis.

Objective: To explore the role of cellular communication network factor 1 (CCN1) in cartilage inflammaging and osteoarthritis (OA) pathogenesis in the isolated primary human chondrocytes in vitro, cartilage explants ex vivo, and a pre-clinical mice model.

Methods: Recombinant human CCN1 stimulation and small interfering RNA inhibition were conducted in human chondrocytes. The RNA was extracted to quantify catabolic targets and pro-inflammatory genes and the proteins were probed with specific antibodies.

Bronchial mucosal inflammation and illness severity in response to experimental rhinovirus infection in COPD.

Background: Respiratory viral infection causes chronic obstructive pulmonary disease (COPD) exacerbations. We previously reported increased bronchial mucosa eosinophil and neutrophil inflammation in patients with COPD experiencing naturally occurring exacerbations. But it is unclear whether virus per se induces bronchial mucosal inflammation, nor whether this relates to exacerbation severity.

Responses of Two Coastal Algae (Skeletonema costatum and Chlorella vulgaris) to Changes in Light and Iron Levels.

Iron (Fe) is essential for phytoplankton growth and photosynthesis, and is proposed to be an important factor regulating algal blooms under replete major nutrients in coastal environments. Here, Skeletonema costatum, a typical red-tide diatom species, and Chlorella vulgaris, a widely distributed Chlorella, were chosen to examine carbon fixation and Fe uptake by coastal algae under dark and light conditions with different Fe levels. The cellular carbon fixation and intracellular Fe uptake were measured via C and Fe tracer assay, respectively.

Hyperglycemia compromises Rat Cortical Bone by Increasing Osteocyte Lacunar Density and Decreasing Vascular Canal Volume.

Uncontrolled diabetes is associated with increased risk of bony fractures. However, the mechanisms have yet to be understood. Using high-resolution synchrotron micro-CT, we calculated the changes in the microstructure of femoral cortices of streptozotocin-induced hyperglycemic (STZ) Wistar Albino rats and tested the mechanical properties of the mineralized matrix by nanoindentation.

Transcription Factor Enrichment Analysis in Enhancers Identifies EZH2 as a Susceptibility Gene for Osteoporosis.

Purpose: Genome-wide association studies (GWASs) have identified hundreds of single nucleotide polymorphisms (SNPs) associated with osteoporosis. Most of these SNPs are noncoding variants and could be mapped to enhancers. Transcription factors (TFs) play important roles in gene regulation via enhancers harboring these SNPs; thus, we aimed to identify common regulatory TFs binding to enhancers associated with osteoporosis.

SUMO-modified bone marrow mesenchymal stem cells promoted the repair of articular cartilage in rats.

Articular cartilage damage can lead to joint deformity, pain, and severe dysfunction. However, due to the lack of blood vessels and nerves in articular cartilage, the self-healing capacity of damaged cartilage is limited. In this study, we overexpressed small ubiquitin-like modifier (SUMO)1, SUMO2/3, and SUMO1/2/3 in bone marrow mesenchymal stem cells (BMSCs).