The Role of Receptor Activator of Nuclear Factor-κB Ligand/Osteoprotegerin Ratio in Synovial Fluid as a Potential Marker for Periprosthetic Osteolysis Following Total Ankle Arthroplasty.

Background: Periprosthetic osteolysis is a prevalent complication following total ankle arthroplasty (TAA), implicating various cytokines in osteoclastogenesis as pivotal in this process. This study aimed to evaluate the relationship between osteolysis and the concentrations of osteoclastogenesis-related cytokines in synovial fluid and investigate its clinical value following TAA. Methods: Synovial fluid samples from 23 ankles that underwent revision surgery for osteolysis following TAA were analyzed as the osteolysis group. As a control group, we included synovial fluid samples obtained from 23 ankles during primary TAA for osteoarthritis. The receptor activator of nuclear factor-κB ligand (RANKL)/osteoprotegerin (OPG) ratio in these samples was quantified using sandwich enzyme-linked immunosorbent assay techniques, and a bead-based multiplex immunoassay facilitated the detection of specific osteoclastogenesis-related cytokines. Results: RANKL levels averaged 487.9 pg/mL in 14 of 23 patients in the osteolysis group, with no detection in the control group's synovial fluid. Conversely, a significant reduction in OPG levels was observed in the osteolysis group (p = 0.002), resulting in a markedly higher mean RANKL/OPG ratio (0.23) relative to controls (p = 0.020). Moreover, the osteolysis group had increased concentrations of various osteoclastogenesis-related cytokines (tumor necrosis factor-α, interleukin [IL]-1ß, IL-6, IL-8, IP-10, and monocyte chemotactic protein-1) in the synovial fluid relative to the control group. Conclusions: Our results demonstrated that periprosthetic osteolysis was associated with osteoclastogenesis activation through an elevated RANKL/OPG ratio following TAA. We assume that RANKL and other osteoclastogenesis-related cytokines in the synovial fluid have clinical value as a potential marker for the development and progression of osteolysis following TAA.

Comparison of Intermediate-Term Outcomes of Total Ankle Arthroplasty in Patients Younger and Older Than 55 Years.

BACKGROUND: Total ankle arthroplasty is often not recommended to younger patients with ankle arthritis because of their high functional demands. The purpose of this study was to compare intermediate-term clinical and radiographic outcomes and survivorship rates of total ankle arthroplasty between patients younger and older than 55 years. METHODS: A total of 117 consecutive patients (123 ankles) who underwent primary total ankle arthroplasty using Hintegra prosthesis with a mean follow-up of 78 months were enrolled and divided into 2 age groups: under 55 years (38 ankles; mean age 45 years) and over 55 years (85 ankles; mean age 65 years). RESULTS: Clinical scores of Ankle Osteoarthritis Scale pain and disability, American Orthopaedic Foot & Ankle Society ankle-hindfoot, Short Form-36 Physical Component Summary and Mental Component Summary, and visual analog scale were not significantly different between the 2 age groups at the final follow-up (P > .05). There were no significant differences in complications and survivorship rates between the two at a mean follow-up of 78 months (P > .05). CONCLUSIONS: Clinical and radiographic outcomes and survival rates of total ankle arthroplasty in patients under age of 55 years were satisfactory and comparable to those in patients older than 55 years in the intermediate-term follow-up. Therefore, total ankle arthroplasty may be considered as a viable treatment option in young patients with end-stage ankle arthritis. LEVEL OF EVIDENCE: Level III, comparative series, therapeutic.

Epigallocatechin-3-gallate Inhibits LPS-Induced NF-κB and MAPK Signaling Pathways in Bone Marrow-Derived Macrophages.

BACKGROUND/AIMS: Epigallocatechin-3-gallate (EGCG), the primary catechin in green tea, has anti-inflammatory and anti-oxidative properties. The aim of the current study was to characterize the impact of EGCG on lipopolysaccharide (LPS)-induced innate signaling in bone marrow-derived macrophages (BMMs) isolated from ICR mice. METHODS: The effect of EGCG on LPS-induced pro-inflammatory gene expression and nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) signaling was examined using reverse transcription-polymerase chain reaction, Western blotting, immunofluorescence, and the electrophoretic mobility shift assay. RESULTS: EGCG inhibited accumulation of LPS-induced IL-12p40, IL-6, MCP-1, ICAM-1, and VCAM-1 mRNA in BMMs. EGCG blocked LPS-induced IκBα degradation and RelA nuclear translocation. EGCG blocked the DNA-binding activity of NF-κB. LPS-induced phosphorylation of ERK1/2, JNK, and p38 was inhibited by EGCG. U0126 (an inhibitor of MEK-1/2) suppressed the LPS-induced IL-12p40, IL-6, MCP-1, ICAM-1, and VCAM-1 mRNA accumulation in BMMs. CONCLUSIONS: These results indicate that EGCG may prevent LPS-induced pro-inflammatory gene expression through blocking NF-κB and MAPK signaling pathways in BMMs.

Topical embryonic stem cells enhance wound healing in diabetic rats.

The effects of embryonic stem cells (ESCs) on diabetic wound healing were investigated using an excisional skin wound model in 110 diabetes-induced rats. We transplanted a clonal population of ESCs (5 × 10(6)) by topical injection into full thickness skin wounds. Four study groups were used; nondiabetic rats as a control, non-insulin controlled diabetic rats not treated with ESCs, insulin controlled diabetic rats not treated with ESCs, and insulin controlled diabetic rats treated with ESCs. Five rats in each experimental group were sacrificed on days 1, 5, 10, 15, and 20 after wounding. Wounds images were acquired daily and wound sizes were calculated. We measured the mRNA levels of epidermal growth factor (EGF) and vascular endothelial growth factor (VEGF), and fibronectin levels in extracellular matrix, and assessed wound healing by assessing histological parameters of epidermal regeneration, granulation tissue thickness, and angiogenesis. In the ESC-treated group, wound sizes were significantly smaller than in the insulin controlled diabetic group not treated with ESCs on days 5 and 10 (p < 0.05), and EGF and VEGF levels were markedly higher on days 5 and 10, fibronectin levels on day 5 after injection. All histological scores in the ESC-treated group were significantly higher than those of the insulin controlled diabetic group on day 5 (p < 0.05). Our results shows that topical ESCs enhance diabetic wound healing during the early stage, and suggest that ESCs transplantation offers a novel therapeutic modality for the treatment of diabetic wounds.

A repressor complex, AP4 transcription factor and geminin, negatively regulates expression of target genes in nonneuronal cells.

The transcription of neuron-specific genes must be repressed in nonneuronal cells. REST/NRSF is a transcription factor that restricts the expression of many neuronal genes through interaction with the neuron-restrictive silencer element at the promoter level. PAHX-AP1 is a neuronal gene that is developmentally up-regulated in the adult mouse brain but that has no functional NRSE motif in its 5' upstream sequence. Here, we report that the transcription factor AP4 and the corepressor geminin form a functional complex in which SMRT and histone deacetylase 3 are recruited. The functional complex represses PAHX-AP1 expression in nonneuronal cells and participates in regulating the developmental expression of PAHX-AP1 in the brain. This complex also serves as a transcriptional repressor of DYRK1A, a candidate gene for Down's syndrome. Furthermore, compared with that in normal fetal brain, the expression of AP4 and geminin is reduced in Down's syndrome fetal brain at 20 weeks of gestation age, at which time premature overexpression of dual-specificity tyrosine-phosphorylated and regulated kinase 1A (DYRK1A) is observed. Our findings indicate that AP4 and geminin act as a previously undescribed repressor complex distinct from REST/NRSF to negatively regulate the expression of target genes in nonneuronal cells and suggest that the AP4-geminin complex may contribute to suppressing the precocious expression of target genes in fetal brain.

Suppression of progression and metastasis of established colon tumors in mice by intravenous delivery of short interfering RNA targeting KITENIN, a metastasis-enhancing protein.

KITENIN promotes invasion of mouse colon adenocarcinoma (CT-26) cells in vivo. Here, we studied the effects of in vivo KITENIN ablation on established tumors by using pSUPER vectors (pSUPER-KITENIN) producing short interfering RNA (siRNA). When pSUPER-KITENIN was given weekly or semiweekly for 1 month into tail vein of syngeneic mice that have established colon tumors, tumor size regressed markedly and metastases were inhibited. In mice injected with pSUPER-KITENIN, serum interleukin-2 (IL-2) and IFN-gamma increased and CD4+ and CD8+ T cells infiltrated in the regressed tumor tissues. These effects, observed beginning 2 days after i.v. injection, imply that immune response is involved in the antitumor action of pSUPER-KITENIN. Using a yeast two-hybrid assay, we identified two KITENIN-interacting proteins for the possible mediators of these actions: 90K protein, a known immune modulatory glycoprotein, and protein kinase C inhibitor (PKCI). 90K was increased in the culture medium from CT-26/antisense KITENIN/90K cells. Double culture of accessory cells with CT-26/antisense KITENIN/90K cells revealed increased secretion of IL-1 and IL-6. Overexpression of 90K in CT-26/antisense KITENIN cells further delayed tumor growth compared with that of CT-26/antisense KITENIN cells. Actin arrangement was distorted in CT-26/antisense KITENIN and CT-26/antisense PKCI cells, whereas overexpression of PKCI resulted in increased invasiveness to fibronectin. Thus, antitumor effects of KITENIN siRNA derives from both the generation of a tumor-specific immune response in vivo through increased 90K secretion from tumor cells and the suppression of tumor invasion in which PKCI is related to increased invasiveness. Moreover, siRNA targeting of KITENIN can function as a chemotherapeutic strategy against colon cancer.

Vaccination with DNA encoding human T-cell epitopes suppresses Der p induced allergic responses in mice.

The apparent complexity of allergen-specific T-cell response in terms of epitope usage in humans is a potential barrier to peptide-based immunotherapy for allergy. A knowledge of cross-reacting T-cell epitopes of common allergens might have an impact on the development of vaccines for immunotherapy. We examined the efficiency of vaccinating with plasmid DNA coding only human T-cell epitopes on the suppression of allergic reactions in mice. BALB/c mice that received an injection of mixed naked DNA plasmids encoding the five classes of human T-cell epitopes on Der p 1 and Der p 2 produced a significant reduction in total and Der p-specific immunoglobulin E (IgE) synthesis. In Der p specific-IgG2a antibody responses, vaccinated mice showed more prominent responses than controls. Higher levels of interferon-gamma, a Th1 cytokine associated with the suppression of IgE production, were found in the sera of vaccinated mice. Histologic studies showed a marked reduction in the infiltration of inflammatory cells in the lung tissues of vaccinated mice vs. controls. These results suggest that vaccination with DNA encoding human T-cell epitopes effectively inhibits allergic responses in mice and might induce cross-regulation on helper T-cell level in vivo.