Visceral fat obesity predicts ossification of the posterior longitudinal ligament: annual health examination data-based evidence.

Background Context: Recent studies have demonstrated a close association between the development of ossification of the posterior longitudinal ligament (OPLL) and obesity. However, the association between OPLL and visceral fat obesity, which is prevalent in the Asian population, remains unexplored.

Purpose: To examine the impact of visceral fat obesity on the development of asymptomatic OPLL.

Therapeutic Potential of Targeting Ferroptosis in Periprosthetic Osteolysis Induced by Ultra-High-Molecular-Weight Polyethylene Wear Debris.

Periprosthetic osteolysis is the primary cause of arthroplasty failure in the majority of patients. Mechanistically, wear debris released from the articulating surfaces of a prosthesis initiates local inflammation and several modes of regulated cell death programs, such as ferroptosis, which represents a promising therapeutic target in various chronic inflammatory diseases. Thus, the current study aimed at exploring the therapeutic potential of targeting ferroptosis in a polyethylene-wear-debris-induced osteolysis model.

Associations between glycan signature alterations and the cellular antigenic properties of passaged chondrocytes.

Background: Cartilage repair is a significant clinical challenge because of the limited intrinsic healing capacity. Current therapeutic strategies, such as cell transplantation therapy, aim to overcome this challenge by replacing damaged tissue with healthy cells. However, the long-term survival and functionality of transplanted cells remain major hurdles.

GFRα1 Promotes Axon Regeneration after Peripheral Nerve Injury by Functioning as a Ligand.

The neurotrophic factor, Glial cell line derived neurotrophi factor (GDNF), exerts a variety of biological effects through binding to its receptors, GDNF family receptor alpha-1 (GFRα1), and RET. However, the existence of cells expressing GFRα1 but not RET raises the possibility that GFRα1 can function independently from RET. Here, it is shown that GFRα1 released from repair Schwann cells (RSCs) functions as a ligand in a GDNF-RET-independent manner to promote axon regeneration after peripheral nerve injury (PNI).

Cellular communication network factor 3 contributes to the pathological process of rheumatoid arthritis through promoting cell senescence and osteoclastogenesis in the joint.

Rheumatoid arthritis (RA) is a chronic systemic and autoimmune disease that primarily affects joints and causes pain, stiffness and swelling. The affected joints exhibit severe inflammation in the synovium and bone erosion, leading to joint deformity. Aging is an important factor facilitating the development of RA, as it is associated with an increase in the number of senescent cells and the production of the autoantibodies and proinflammatory cytokines in tissues.

Dynamic transcriptome analysis of osteal macrophages identifies a distinct subset with senescence features in experimental osteoporosis.

Given the potential fundamental function of osteal macrophages in bone pathophysiology, we study here their precise function in experimental osteoporosis. Gene profiling of osteal macrophages from ovariectomized mice demonstrated the upregulation of genes that were involved in oxidative stress, cell senescence, and apoptotic process. A single-cell RNA-Seq analysis revealed that osteal macrophages were heterogeneously clustered into 6 subsets that expressed proliferative, inflammatory, antiinflammatory, and efferocytosis gene signatures.

Ossification of the posterior longitudinal ligament is linked to heterotopic ossification of the ankle/foot tendons.

Introduction: Systemic osteogenesis has been speculated to be involved in the pathogenesis of ossification of the posterior longitudinal ligament (OPLL). Our purpose was to compare the radiologic prevalence and severity of heterotopic ossification in foot tendons of Japanese patients with OPLL and to determine their association with systemic heterotopic ossification.

Materials And Methods: Clinical and radiographic data of 114 patients with OPLL were collected from 2020 to 2022.

High whole-body bone mineral density in ossification of the posterior longitudinal ligament.

Background Context: Recent studies suggest that ossification of the posterior longitudinal ligament (OPLL) is exacerbated by systemic metabolic disturbances, including obesity. However, although an increase in bone mineral density (BMD) measured at the lumbar spine has been reported in patients with OPLL, no studies have investigated the systemic BMD of patients with OPLL in detail.

Purpose: We investigated whether patients with OPLL develop increased whole-body BMD.

Noncanonical Pyroptosis Triggered by Macrophage-Derived Extracellular Vesicles in Chondrocytes Leading to Cartilage Catabolism in Osteoarthritis.

Objective: The severity of osteoarthritis (OA) and cartilage degeneration is highly correlated with the development of synovitis, which is mediated by the activity of inflammatory macrophages. A better understanding of intercellular communication between inflammatory macrophages and chondrocytes should aid in the discovery of novel therapeutic targets. We undertook this study to explore the pathologic role of inflammatory macrophage extracellular vesicles (EVs) in cartilage degeneration.

Lumbar ossification of the ligamentum flavum reflects a strong ossification tendency of the entire spinal ligament.

Patients with ossification of the ligamentum flavum (OLF) in the lumbar spine may be at high risk of developing concomitant ossification of the entire spinal ligament, but the etiology remains unclear. We investigated the propensity for spinal ligament ossification in asymptomatic subjects with lumbar OLF using the data of 595 Japanese individuals receiving medical check-ups, including computed tomography (CT) scanning. The severity of OLF (total number of intervertebral segments with OLF) of the entire spine on CT was quantified using an OLF index.

Spinal Canal and Spinal Cord in Rat Continue to Grow Even after Sexual Maturation: Anatomical Study and Molecular Proposition.

Although rodents have been widely used for experimental models of spinal cord diseases, the details of the growth curves of their spinal canal and spinal cord, as well as the molecular mechanism of the growth of adult rat spinal cords remain unavailable. They are particularly important when conducting the experiments of cervical spondylotic myelopathy (CSM), since the disease condition depends on the size of the spinal canal and the spinal cord. Thus, the purposes of the present study were to obtain accurate growth curves for the spinal canal and spinal cord in rats; to define the appropriate age in weeks for their use as a CSM model; and to propose a molecular mechanism of the growth of the adult spinal cord in rats.

Molecular and Regenerative Characterization of Repair and Non-repair Schwann Cells.

Although evidence has accumulated to indicate that Schwann cells (SCs) differentiate into repair SCs (RSCs) upon injury and that the unique phenotype of these cells allow them to provide support for peripheral nerve regeneration, the details of the RSCs are not fully understood. The findings of the current study indicate that the RSCs have enhanced adherent properties and a greater capability to promote neurite outgrowth and axon regeneration after peripheral nerve injury, compared to the non-RSCs. Further, transcriptome analyses have demonstrated that the molecular signature of the RSCs is distinctly different from that of the non-RSCs.

Neutrophils delay repair process in Wallerian degeneration by releasing NETs outside the parenchyma.

Although inflammation is indispensable for the repair process in Wallerian degeneration (WD), the role of neutrophils in the WD repair process remains unclear. After peripheral nerve injury, neutrophils accumulate at the epineurium but not the parenchyma in the WD region because of the blood-nerve barrier. An increase or decrease in the number of neutrophils delayed or promoted macrophage infiltration from the epineurium into the parenchyma and the repair process in WD.

Inhibitory role of Annexin A1 in pathological bone resorption and therapeutic implications in periprosthetic osteolysis.

There is currently no therapy available for periprosthetic osteolysis, the most common cause of arthroplasty failure. Here, the role of AnxA1 in periprosthetic osteolysis and potential therapeutics were investigated. Reducing the expression of AnxA1 in calvarial tissue was found to be associated with increased osteolytic lesions and the osteolytic lesions induced by debris implantation were more severe in AnxA1-defecient mice than in wild-type mice.

Retrograde Axonal Transport of Liposomes from Peripheral Tissue to Spinal Cord and DRGs by Optimized Phospholipid and CTB Modification.

Despite recent advancements in therapeutic options for disorders of the central nervous system (CNS), the lack of an efficient drug-delivery system (DDS) hampers their clinical application. We hypothesized that liposomes could be optimized for retrograde transport in axons as a DDS from peripheral tissues to the spinal cord and dorsal root ganglia (DRGs). Three types of liposomes consisting of DSPC, DSPC/POPC, or POPC in combination with cholesterol (Chol) and polyethylene glycol (PEG) lipid were administered to sciatic nerves or the tibialis anterior muscle of mature rats.

IL4 stimulated macrophages promote axon regeneration after peripheral nerve injury by secreting uPA to stimulate uPAR upregulated in injured axons.

Accumulating evidences suggest that M2 macrophages are involved with repair processes in the nervous system. However, whether M2 macrophages can promote axon regeneration by directly stimulating axons nor its precise molecular mechanism remains elusive. Here, the current study demonstrated that typical M2 macrophages, which were generated by IL4 simulation, had the capacity to stimulate axonal growth by their direct effect on axons and that the graft of IL4 stimulated macrophages into the region of Wallerian degeneration enhanced axon regeneration and improved functional recovery after PNI.

Comprehensive validation of a wearable foot sensor system for estimating spatiotemporal gait parameters by simultaneous three-dimensional optical motion analysis.

Background: Use of a wearable gait analysis system (WGAS) is becoming common when conducting gait analysis studies due to its versatility. At the same time, its versatility raises a concern about its accuracy, because its calculations rely on assumptions embedded in its algorithms. The purpose of the present study was to validate twenty spatiotemporal gait parameters calculated by the WGAS by comparison with simultaneous measurements taken with an optical motion capture system (OMCS).