Transcriptomic Changes During the Replicative Senescence of Human Articular Chondrocytes.

Aging is a major risk factor for osteoarthritis (OA), but the specific mechanisms connecting aging and OA remain unclear. Although chondrocytes rarely divide in adult articular cartilage, they undergo replicative senescence in vitro, offering a model to study aging-related changes under controlled conditions. OA cartilage was obtained from an 80-year-old male and a 72-year-old female, while normal cartilage was sourced from a 26-year-old male.

Transcriptomic changes during the replicative senescence of human articular chondrocytes.

Osteoarthritis (OA) is a degenerative joint disease and a leading cause of disability worldwide. Aging is a major risk factor for OA, but the specific mechanisms underlying this connection remain unclear. Although chondrocytes rarely divide in adult articular cartilage, they undergo replicative senescence which provides an opportunity to study changes related to aging under controlled laboratory conditions.

Segmental defect healing in the presence or absence of recombinant human BMP2: Novel insights from a rat model.

This study defined and compared the course of native, impaired and growth factor-stimulated bone regeneration in a rat femoral defect model. A mid-diaphyseal defect with rigid internal fixation was surgically created in the right femur of male Fischer rats and serially analyzed over 36 weeks. Native bone regeneration was modeled using a sub-critical, 1 mm size defect, which healed uneventfully.

Expedited gene delivery for osteochondral defect repair in a rabbit knee model: A one-year investigation.

Objective: To evaluate a single-step, gene-based procedure for repairing osteochondral lesions.

Design: Osteochondral lesions were created in the patellar groove of skeletally mature rabbits. Autologous bone marrow aspirates were mixed with adenovirus vectors carrying cDNA encoding green fluorescent protein (Ad.

IL-1Ra gene transfer potentiates BMP2-mediated bone healing by redirecting osteogenesis toward endochondral ossification.

An estimated 100,000 patients each year in the United States suffer severe disability from bone defects that fail to heal, a condition where bone-regenerative therapies could provide substantial clinical benefits. Although recombinant human bone morphogenetic protein-2 (rhBMP2) is an osteogenic growth factor that is clinically approved for this purpose, it is only effective when used at exceedingly high doses that incur substantial costs, induce severe inflammation, produce adverse side effects, and form morphologically abnormal bone. Using a validated rat femoral segmental defect model, we show that bone formed in response to clinically relevant doses of rhBMP2 is accompanied by elevated expression of interleukin-1 (IL-1).

Picrosirius Red Staining: Revisiting Its Application to the Qualitative and Quantitative Assessment of Collagen Type I and Type III in Tendon.

Collagen has a major role in the structural organization of tendons. Picrosirius red (PSR) staining viewed under polarized light microscopy is the standard method to evaluate the organization of collagen fibers in tissues. It is also used to distinguish between type I and type III collagen in tissue sections.

Contribution of Implanted, Genetically Modified Muscle Progenitor Cells Expressing BMP-2 to New Bone Formation in a Rat Osseous Defect.

Because muscle contains osteoprogenitor cells and has a propensity to form bone, we have explored its utility in healing large osseous defects. Healing is achieved by the insertion of muscle fragments transduced with adenovirus encoding BMP-2 (Ad.BMP-2).

Gene Expression Profiling in Blood and Affected Muscle Tissues Reveals Differential Activation Pathways in Patients with New-onset Juvenile and Adult Dermatomyositis.

Objective: To identify shared and differential molecular pathways in blood and affected muscle between adult dermatomyositis (DM) and juvenile DM, and their association with clinical disease activity measures.

Methods: Gene expression of transcription factors and cytokines involved in differentiation and effector function of T cell subsets, regulatory T cells and follicular Th cells, were analyzed in the blood from 21 newly diagnosed adult and 26 juvenile DM subjects and in 15 muscle specimens (7 adult and 8 juvenile DM) using a custom RT2 Profiler PCR Array. Disease activity was determined and measured by established disease activity tools.

Interferon-regulated chemokine score associated with improvement in disease activity in refractory myositis patients treated with rituximab.

Objectives: The purpose of this study was to investigate whether serum interferon (IFN)-regulated chemokine and distinct cytokine response profiles are associated with clinical improvement in patients with refractory inflammatory myopathy treated with rituximab.

Methods: In a randomised, placebo-phase trial Rituximab in Myositis Trial (RIM), 200 refractory adult and paediatric myositis subjects received rituximab. Following rituximab, clinical response and disease activity were assessed.

The type I interferons: Basic concepts and clinical relevance in immune-mediated inflammatory diseases.

There is increasing scientific and clinical interest in elucidating the biology of type I Interferons, which began approximately 60 years ago with the concept of "viral interference", a property that reduces the ability of a virus to infect cells. Although our understanding of the multiple cellular and molecular functions of interferons has advanced significantly, much remains to be learned and type I Interferons remain an active and fascinating area of inquiry. In this review, we cover some general aspects of type I interferon genes, with emphasis on interferon-alpha, and various aspects of molecular mechanisms triggered by type I interferons and toll-like receptor signaling by the Janus activated kinase/signal transducer activation of transcription (JAK-STAT) pathway and interferon regulatory factor pathway.

Biologic predictors of clinical improvement in rituximab-treated refractory myositis.

Background: To examine the longitudinal utility of a biomarker signature in conjunction with myositis autoantibodies (autoAbs) as predictors of disease improvement in refractory myositis patients treated with rituximab.

Methods: In the RIM Trial, all subjects received rituximab on 2 consecutive weeks. Using start of treatment as baseline, serum samples (n = 177) were analyzed at baseline and after rituximab with multiplexed sandwich immunoassays to quantify type-1 IFN-regulated and other pro-inflammatory chemokines and cytokines.

Adipokine gene expression in peripheral blood of adult and juvenile dermatomyositis patients and their relation to clinical parameters and disease activity measures.

Objective: Recently adipokines have been implicated in the regulation of immune and inflammatory responses in autoimmune disease. To investigate the role of adipokines in adult and pediatric patients with newly diagnosed dermatomyositis (DM), we analyzed peripheral blood and skeletal muscle gene expression of four adipokines: visfatin, leptin, adiponectin and resistin.

Methods: Peripheral blood mononuclear cells (PBMCs) were collected for 21 adult DM, 26 juvenile DM, 5 non-disease adult controls, and 6 non-disease pediatric controls at two time points: baseline and 6 months.

Longitudinal peripheral blood lymphocyte subsets correlate with decreased disease activity in juvenile dermatomyositis.

Objective: To determine the clinical characteristics and subsets of peripheral blood lymphocytes (PBL), which correlate with decreased disease activity in patients with juvenile dermatomyositis (JDM).

Methods: Peripheral blood mononuclear cells from 24 patients with JDM were collected at Mayo Clinic Rochester between 2007 and 2011. These were analyzed using fluorescence-activated cell sorting and flow cytometry.

BAFF expression correlates with idiopathic inflammatory myopathy disease activity measures and autoantibodies.

Objective: To investigate B cell survival cytokine messenger RNA (mRNA) levels as biomarkers of idiopathic inflammatory myopathies (IIM).

Methods: We measured and compared mRNA levels of B cell survival cytokines by quantitative real-time polymerase chain reaction in 98 patients with IIM, 38 patients with systemic lupus erythematosus, and 21 healthy controls. The cytokines were B cell-activating factor belonging to the tumor necrosis factor family (BAFF); ΔBAFF; and a proliferation-inducing ligand (APRIL); and their receptors BAFF-R, transmembrane activator and calcium modulator and cyclophilin ligand interactor, and B cell maturation antigen (BCMA).

Increased expression of ADAMTS13 mRNA correlates with ischemic cerebrovascular disease in systemic lupus erythematosus patients.

Objective: We investigated ADAMTS13 (a disintegrin-like and metalloprotease with thrombospondin type 1 motif, member 13) messenger RNA levels as a biomarker of disease features in systemic lupus erythematosus.

Methods: We measured and compared messenger RNA (mRNA) levels of ADAMTS13 in peripheral blood cells in patients with systemic lupus erythematosus and healthy control subjects by whole-genome microarray. We retrospectively analyzed the correlations of ADAMTS13 mRNA expression with clinical features, laboratory parameters, therapeutic features, and disease activity (according to the Systemic Lupus Erythematosus Disease Activity Index).

Extranodal lymphoid microstructures in inflamed muscle and disease severity of new-onset juvenile dermatomyositis.

Objective: Juvenile dermatomyositis (DM) is an autoimmune disease of childhood characterized by lesions in skin and muscle that are populated by plasmacytoid dendritic cells (PDCs) and lymphocyte infiltrates. We undertook this study to examine the cellular composition, organization, and molecular milieu of the cellular infiltrates in muscle in juvenile DM and to correlate the infiltrates with clinical disease manifestations.

Methods: Since PDCs and lymphocyte foci express CCL19 and CCL21, we investigated for in situ formation of lymphoid microstructures that could be sites of extranodal immune activation.

Involvement of dendritic cells in autoimmune diseases in children.

Dendritic cells (DCs) are professional antigen-presenting cells that are specialized in the uptake of antigens and their transport from peripheral tissues to the lymphoid organs. Over the last decades, the properties of DCs have been intensely studied and much knowledge has been gained about the role of DCs in various diseases and health conditions where the immune system is involved, particularly in cancer and autoimmune disorders. Emerging clues in autoimmune diseases, suggest that dendritic cell dysregulation might be involved in the development of various autoimmune disorders in both adults and children.

Plasmacytoid dendritic cells in inflamed muscle of patients with juvenile dermatomyositis.

Objective: To examine whether dendritic cells (DCs) are constituents of muscle inflammation in juvenile dermatomyositis (DM).

Methods: The types, numbers, and activation state of DC subsets in inflamed muscle tissue from patients with juvenile DM and in noninflamed muscle tissue from control subjects were examined by multicolor immunofluorescence. Chemokine expression of the muscle-infiltrating cells was examined by laser capture microdissection and quantitative polymerase chain reaction.