Synovial-tissue resident macrophages play proinflammatory functions in the pathogenesis of RA while maintaining the phenotypes in the steady state

Synovial tissue-resident macrophages (STRMs) maintain normal joint homeostasis in a steady state. However, it is unclear whether STRMs still play homeostatic roles or change the functions in the joint of rheumatoid arthritis (RA), where infiltrating peripheral blood monocyte-derived macrophages (PBMoMs) play proinflammatory roles. In the present study, we examined changes in the phenotypes and functions of STRMs in response to RA-related stimuli in vitro. STRMs were prepared from non-inflammatory osteoarthritis (OA) joint synovium, which is histologically indistinguishable from normal joint synovium. PBMoMs were prepared and used for comparison. After stimulation with plate-bound IgG, which mimics anti-citrullinated protein antibody immunocomplex formed in RA joints, or with combinations of RA-related inflammatory mediators, namely tumor necrosis factor-α (TNF-α) and prostaglandin E2 or interferon-γ, PBMoMs downregulated surface markers and genes associated with anti-inflammatory macrophages, and upregulated cytokine and marker genes of proinflammatory macrophages in RA. On the other hand, STRMs hardly changed the expression of surface molecules and marker genes but altered the pattern of cytokine gene expression after stimulation like PBMoMs. Furthermore, in vitro stimulated STRMs promote proinflammatory functions of cocultured synovial fibroblasts. Thus, STRMs might play proinflammatory roles in RA joints, while maintaining their phenotypes in the steady state.

Is there a reduction in hip destruction under a treat-to-target strategy in patients with rheumatoid arthritis?

OBJECTIVES

The treatments for rheumatoid arthritis (RA) have been greatly improved, and the tight control of disease activity yields superior clinical outcomes. This study aimed to elucidate the accompanying changes in hip destruction following the implementation of a treat-to-target strategy for patients with RA.

METHODS

We extracted 190 hips over two periods, i.e. the early period (1998-2003) and the late period (2013-19), with 103 and 87 hips, respectively. The observed rheumatic changes, such as inward migration, upward migration, and femoral head collapse, were quantitatively evaluated, while osteoarthritic changes, such as the formation of a capital drop, were investigated from radiographs before primary total hip arthroplasty.

RESULTS

A comparison of the two periods' data showed that the degree of inward migration (-3.44 vs. -7.45 mm; P < .001) and upward migration (+4.3 vs. +0.95 mm; P < .001) significantly decreased in the late-period group. The collapse of the femoral head was not significantly different. The incidence of capital drops was significantly higher in the late-period group (7.8% vs. 27.5%; P < .001).

CONCLUSIONS

The degree of inward and upward migration representative of rheumatic changes reduced, whereas the frequency of capital drops as osteoarthritic changes increased during the late period.

Complications After Orthopedic Surgeries in Patients with Rheumatoid Arthritis Treated with Janus Kinase Inhibitors: a Retrospective Observational Study

OBJECTIVES

The current study compared the outcome after orthopedic surgeries in patients with RA receiving JAKi versus biologic disease-modifying anti-rheumatic drugs (bDMARDs).

METHODS

This was a retrospective observational study of Japanese patients with RA. Sixty-two patients with RA using JAKi preoperatively underwent orthopedic surgeries. Using propensity score matching, these 62 patients were matched with 62 patients using bDMARDs preoperatively. The number of adverse events was counted. We also examined whether the drug-withholding period in the JAKi-treated group was associated with the occurrence of major postoperative adverse events, namely inflammatory flares and delayed wound healing (DWH).

RESULTS

JAKi-treated patients had a higher incidence of postoperative flares than bDMARDs-treated patients (29% vs 12.1%, p=0.01). The incidences of postoperative complications other than flares were not significantly different between the two groups. Among the JAKi-treated group, a longer perioperative drug-withholding period (≥11 days) was associated with a higher incidence of postoperative flares (p=0.04). The incidences of DWH and SSI were not associated with the duration of the JAKi withholding period.

CONCLUSION

JAKi-treated patients had a higher incidence of postoperative flares than bDMARDs-treated patients. A total of 11 days or more of drug withdrawal was associated with postoperative flares.

Interaction between functional capability and sleep quality at midterm after total knee arthroplasty: a Japanese retrospective cohort study

No report has clarified the frequency and interacting factors affecting sleep disturbance among Asian patients at midterm after total knee arthroplasty (TKA). This study aimed to evaluate the frequency of sleep disturbance at midterm after TKA in a Japanese cohort and to identify intervening factors for sleep. We hypothesized that residual knee pain and decreased functional capability negatively interact with sleep quality after TKA. A total of 209 Japanese participants (average age: 77.1 ± 8.3 years; postoperative follow-up period: 4.5 ± 1.9 years) who underwent primary TKA for knee osteoarthritis were included in this study. Sleep quality, satisfaction, pain, functional capability, joint awareness, and mental condition were evaluated using the Pittsburgh Sleep Quality Index (PSQI), Knee Society Score (KSS) 2011, Forgotten Joint Score (FJS)-12, and 12-Item Short-Form Health Survey (SF-12) Mental Component Summary (MCS). Multivariable analysis was performed to determine the influencing factors on PSQI. The scores for the PSQI, satisfaction with pain level while lying in bed, pain during level walking, functional activity category in the KSS 2011, awareness of the artificial joint in bed at night in the FJS-12, and SF-12 MCS were 6.7 ± 3.0, 5.8 ± 1.8, 1.6 ± 2.3, 62 ± 22, 1.5 ± 1.4, and 56 ± 9.3 on average, respectively. Sleep disturbance (PSQI ≥ 5.5) occurred in 54% of the Japanese participants. Multivariable analysis revealed that high functional capability was a significant factor associated with sleep quality improvement (p < 0.05). Decreased functional capability, not residual knee pain, negatively interacted with sleep quality. The sleep disturbance rate was high during the middle postoperative period after TKA in the Japanese cohort.

Arthroscopic Treatment of Septic Arthritis of the Ankle Caused by Group B Streptococcus: A Case Report

BACKGROUND The incidence of septic arthritis of a native joint caused by group B streptococcus (GBS, Streptococcus agalactiae) has been on the rise in non-pregnant women. GBS commonly colonizes the female genital tract. However, only a few reports have discussed serious cases of GBS infection, endocarditis, and joint infection associated with the Papanicolaou (Pap) smear test, which is routinely conducted to detect cervical cancer. Specifically, to the best of our knowledge, there have been few reports about arthroscopic treatment for septic arthritis of the ankle caused by GBS. CASE REPORT A 60-year-old woman, who had previously completed the treatment of total laparoscopic hysterectomy with bilateral adnexectomy and postoperative chemotherapy for ovarian cancer, underwent a routine Pap smear test. Four weeks later, she suddenly presented with high fever and abdominal pain. The pain and swelling in her left ankle gradually worsened. Finally, septic arthritis of the ankle was diagnosed, and thus the patient underwent emergent arthroscopic irrigation and debridement. GBS was isolated from both the ankle fluid and blood culture. After surgical intervention and intravenous antibiotic administration, the patient's symptoms gradually improved. Four months later, the patient had no ankle pain or restriction of ankle motion. CONCLUSIONS Although cervical cytology tests are essential in screening for cervical cancer, transient bacteremia can be induced by the tests. Thus, physicians must watch out for the development of septic arthritis caused by GBS when patients present with fever or swollen joints after a recent Pap smear test. Emergent diagnosis and appropriate surgical intervention is also important.

Similar short-term KOOS between open-wedge high tibial osteotomy and total knee arthroplasty in patients over age 60: A propensity score-matched cohort study

OBJECTIVES

The purpose of the present study was to evaluate improvement in the Knee Injury and Osteoarthritis Outcome Score (KOOS) after open-wedge high tibial osteotomy (HTO) in comparison with total knee arthroplasty (TKA) in cohorts over age 60 matched by pre-operative age, gender, body mass index (BMI), hip-knee-ankle angle (HKAA), KOOS sub-scores, and osteoarthritis (OA) grade.

METHODS

Propensity score matching was performed between 162 HTO patients and 134 TKA patients. When calculating the propensity score by multivariate logistic regression analysis, the following pre-operative confounders were included: age, gender, BMI, HKAA, KOOS sub-scores, and OA grade. Consequently, a total of 55 patients were included in each group. The Student's t-test was used to analyse differences in the post-operative KOOS sub-scores between groups.

RESULTS

After propensity score matching, all matched pre-operative valuables were identical, with no significant differences between the HTO and TKA groups. None of the post-operative KOOS sub-scores at 1 year after surgery showed a significant difference between the HTO and TKA groups. Both groups demonstrated significant and comparable post-operative improvement in every KOOS sub-score.

CONCLUSIONS

In patients over age 60, there was no significant difference in short-term pain relief and improvements in activity and quality of life between HTO and TKA after propensity score matching including pre-operative age, KOOS sub-scores, and OA grade. HTO is a joint preservation procedure that is valid for knee OA even in individuals over age 60.

"Grand-piano sign" as a femoral rotational indicator in both varus and valgus knees: a simulation study of anterior resection surface in total knee arthroplasty

PURPOSE

The "Grand-piano sign" is a popular indicator of the appropriate rotational alignment of the femoral component during total knee arthroplasty (TKA). The aim of the study was to investigate the shape of the anterior femoral resection surface of varus and valgus knees.

METHODS

A cohort of 80 varus knees and 40 valgus knees (hip-knee-ankle angle > 2° for varus and < - 2° for valgus knees) matched for age, sex, height, body weight, and KL grade was made using propensity score matching. Virtual TKA was performed using 3 patterns of components (anterior flange flexion angles of 3°, 5°, and 7°). The anterior femoral resection surface was evaluated for 3 patterns of rotational alignments: parallel to the surgical epicondylar axis (NR, neutral rotation), 3° internal rotation (IR), and 3°external rotation (ER) relative to the surgical epicondylar axis. In each anterior femoral resection surface, the vertical height of medial and lateral condyles was measured, and the ratio of the medial to the lateral height (M/L ratio) was evaluated.

RESULTS

The M/L ratio in NR for both varus and valgus knees was 0.57 to 0.64, with no significant difference between the cohorts (p value > 0.05). The M/L ratio showed a similar pattern of increasing at IR and decreasing at ER in both varus and valgus knees. The variation in the M/L ratio with malrotation in valgus knees was smaller than in varus knees.

CONCLUSION

During TKA, the anterior femoral resection surface was similar in varus and valgus knees; however, the variation with malrotation was smaller in valgus knees than in varus knees. TKA for valgus knees requires precise surgical technique and careful intraoperative assessment.

LEVEL OF EVIDENCE

IV, Case series.

Steroid-induced osteonecrosis of the humeral head in a 20-year-old man treated with an osteochondral autograft: A case report

To our knowledge, only one previous report described the treatment of osteochondral autograft for steroid-induced osteonecrosis of the humeral head (ONHH) in a middle-aged patient. The present report describes a 20-year-old man who was found to have avascular osteonecrosis of the right humeral head after corticosteroid pulse treatment, followed by oral corticosteroid therapy. The patient complained of serious right shoulder pain and limited range of motion (ROM). Anteroposterior (AP) radiographs of the right shoulder revealed a crescent sign at the humeral head, indicating subchondral bone collapse with a linear sclerotic change and normal articular surface of the glenoid. The case was categorized as Stage 3 according to the Cruess classification. In general, Cruess classification Stage 3 is treated with humeral head replacement and shoulder arthroplasty. The patient underwent surgical treatment involving osteochondral autograft transplantation. Autografts were harvested from the right knee. At the 1.5-year follow-up, the patient was pain-free and showed an improved active ROM. Furthermore, AP radiographs demonstrated that the glenohumeral joint space was maintained, and no progression of humeral head collapse was observed. This case may be helpful in decision-making if young patients with ONHH require surgical treatment. Furthermore, osteochondral autograft transplantation may be an effective treatment for ONHH.

Promotion of Knee Cartilage Degradation by IκB Kinase ε in the Pathogenesis of Osteoarthritis in Human and Murine Models

OBJECTIVE

NF-κB signaling is an important modulator in osteoarthritis (OA), and IκB kinase ε (IKKε) regulates the NF-κB pathway. This study was undertaken to identify the functional involvement of IKKε in the pathogenesis of OA and the effectiveness of IKKε inhibition as a modulatory treatment.

METHODS

IKKε expression in normal and OA human knee joints was analyzed immunohistochemically. Gain- or loss-of-function experiments were performed using human chondrocytes. Furthermore, OA was surgically induced in mice, followed by intraarticular injection of BAY-985, an IKKε/TANK-binding kinase 1 inhibitor, into the left knee joint every 5 days for 8 weeks. Mice were subsequently examined for histologic features of cartilage damage and inflammation.

RESULTS

IKKε protein expression was increased in human OA cartilage. In vitro, expression levels of OA-related factors were down-regulated following knockdown of IKKε with the use of small interfering RNA in human OA chondrocytes or following treatment with BAY-985. Conversely, IKKε overexpression significantly increased the expression of OA-related catabolic mediators. In Western blot analysis of human chondrocytes, IKKε overexpression increased the phosphorylation of IκBα and p65. In vivo, intraarticular injection of BAY-985 into the knee joints of mice attenuated OA-related cartilage degradation and hyperalgesia via NF-κB signaling.

CONCLUSION

These results suggest that IKKε regulates cartilage degradation through a catabolic response mediated by NF-κB signaling, and this could represent a potential target for OA treatment. Furthermore, BAY-985 may serve as a major disease-modifying compound among the drugs developed for OA.

Transverse osteotomy closer to tibial plateau is associated with larger postoperative change in valgus laxity after open-wedge high tibial osteotomy

PURPOSE

To identify the factors impacting changes in valgus laxity between before and after open-wedge high tibial osteotomy (OW-HTO) using quantitative valgus stress radiographs.

METHODS

A total of 40 knees from 38 patients who underwent OW-HTO were assessed. The study population comprised 14 men and 24 women, with a mean age of 61.5 years. Valgus stress radiographs before and 1 year after OW-HTO were performed using a Telos device. The difference between pre- and postoperative joint line convergence angle (JLCA) was expressed as ΔJLCA (post-pre). As indicators of the proximal detachment of superficial medial collateral ligament (sMCL) on radiographs, two distances were defined: the distance from the level of the osteotomy starting point to the tangent line of the proximal tibial plateau (Distance A), or to the medial edge of the proximal tibial plateau (Distance B). Correlations between ΔJLCA and radiographic parameters or KOOS sub-scores were assessed using Spearman's rank correlation coefficient analysis. Receiver operator curves were generated to evaluate the predictive strength of the significant factor for an increase in ΔJLCA > 1°.

RESULTS

Pre-operative OA severity consisted of Kellgren-Lawrence grade 2 (n = 18), 3 (n = 16), and 4 (n = 6). The average ΔJLCA (post-pre) was 0.5°, and ranged from - 1.4° to + 3.0°. The maximum systemic measurement error and limits of agreement were 0.07° and 0.20°, respectively. There were significant correlations between ΔJLCA and Distance A (36.9 ± 3.9 mm, R =  - 0.46, p = 0.002), between ΔJLCA and Distance B (39.9 ± 4.0 mm, R =  - 0.49, p = 0.001). The cut-off value for Distance A was determined to be 35 mm below the tibial plateau; the AUC was 0.804, with a sensitivity of 0.75 and a specificity of 0.82. Distance B correlated strongly with Distance A (R = 0.96, p < 0.001). There was no significant correlation between ΔJLCA and KOOS sub-scores 1 year after OW-HTO.

CONCLUSIONS

Transverse osteotomy closer to tibial plateau was associated with larger valgus joint laxity postoperatively. This finding implies that sMCL proximal detachment, which was related to the level of the osteotomy starting point on the proximal tibia, potentially affected postoperative valgus laxity.

LEVEL OF EVIDENCE

IV.

Preoperative Virtual Total Knee Arthroplasty Surgery Using a Computed Tomography-based 3-dimensional Model With Variation in Reference Points and Target Alignment to Predict Femoral Component Sizing

Background

The purpose of this study was to investigate the size differences of 19 different femoral component placements from the standard position in total knee arthroplasty using 3-dimensional virtual surgery.

Methods

Three-dimensional bone models were reconstructed from the computed tomography data of 101 varus osteoarthritic knees. The distal femoral bone was cut perpendicular to the femoral mechanical axis (MA) in the coronal plane. Twenty different component placements consisting of 5 cutting directions (perpendicular to MA, 3° and 5° extension relative to MA [3°E-MA and 5°E-MA, respectively], and 3° and 5° flexion relative to MA [3°F-MA and 5°F-MA, respectively]) in the sagittal plane, 2 rotational alignments (clinical epicondylar axis [CEA] and surgical epicondylar axis [SEA]), and 2 rotational types of anterior reference guide (central [CR] and medial [MR]) were simulated.

Results

The mean anteroposterior dimension of femur ranged from 54.3 mm (5°F-MA, SEA, CR) to 62.5 mm (5°E-MA, CEA, MR). The largest and smallest differences of anteroposterior dimension from the standard position (3°F-MA, SEA, and CR) were 7.1 ± 1.3 mm (5°E-MA, CEA, and MR) and −1.2 ± 0.2 mm (5°F-MA, SEA, and CR), respectively. Multiple regression analysis revealed that flexion cutting direction, SEA, and CR were associated with smaller component size.

Conclusions

The femoral component size can be affected easily by not only cutting direction but also the reference guide type and the target alignment. Our findings could provide surgeons with clinically useful information to fine-tune for unintended loose or tight joint gaps by adjusting the component size.

Fluvastatin promotes chondrogenic differentiation of adipose-derived mesenchymal stem cells by inducing bone morphogenetic protein 2

Background

Adipose-derived mesenchymal stem cells (ADMSCs) are a promising source of material source for medical regeneration of cartilage. Growth factors, including transforming growth factor-β (TGFβ) subfamily members and bone morphogenetic proteins (BMPs), play important roles in inducing and promoting chondrogenic differentiation of MSCs. However, these exogenous growth factors have some drawbacks related to their cost, biological half-life, and safety for clinical application. Several studies have reported that statins, the competitive inhibitors of 3-hydroxy-2-methylglutaryl coenzyme A (HMG-CoA) reductase, induce the expression of BMP2 in multiple cell types as the pleotropic effects. The objective of this study was to investigate the effects of fluvastatin during chondrogenic differentiation of human ADMSCs (hADMSCs).

Methods

The effects of fluvastatin were analyzed during chondrogenic differentiation of hADMSCs in the pellet culture without exogenous growth factors by qRT-PCR and histology. For functional studies, Noggin, an antagonist of BMPs, mevalonic acid (MVA) and geranylgeranyl pyrophosphate (GGPP), metabolites of the mevalonate pathway, ROCK inhibitor (Y27632), or RAC1 inhibitor (NSC23766) were applied to cells during chondrogenic differentiation. Furthermore, RhoA activity was measured by RhoA pulldown assay during chondrogenic differentiation with or without fluvastatin. Statistically significant differences between groups were determined by Student’s t-test or the Tukey–Kramer test.

Results

Fluvastatin-treated cells expressed higher levels of BMP2, SOX9, ACAN, and COL2A1 than control cells, and accumulated higher levels of glycosaminoglycans (GAGs). Noggin significantly inhibited the fluvastatin-mediated upregulation of ACAN and COL2A1. Both MVA and GGPP suppressed the effects of fluvastatin on the expressions of BMP2, SOX9, ACAN, and COL2A1. Furthermore, fluvastatin suppressed the RhoA activity, and inhibition of RhoA–ROCK signaling by Y27632 increased the expressions of BMP2, SOX9, ACAN, and COL2A1, as well as fluvastatin.

Conclusions

Our results suggest that fluvastatin promotes chondrogenic differentiation of hADMSCs by inducing endogenous BMP2, and that one of the mechanisms underlying the effects is inhibition of RhoA–ROCK signaling via suppression of GGPP. Fluvastatin is a safe and low-cost compound that holds promise for use in transplantation of hADMSCs for cartilage regeneration.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40360-022-00600-7.

Sagittal femoral bowing contributes to distal femoral valgus angle deviation in malrotated preoperative radiographs

Background

The coronal whole-leg radiograph is generally used for preoperative planning in total knee arthroplasty. The distal femoral valgus angle (DFVA) is measured for distal femoral bone resection using an intramedullary guide rod. The effect of coronal and sagittal femoral shaft bowing on DFVA measurement in the presence of malrotation or knee flexion contracture has not been well reported. The objectives of this study were: (1) to investigate the effects of whole-leg malrotation and knee flexion contracture on the DFVA in detail, (2) to determine the additional effect of coronal or sagittal femoral shaft bowing.

Methods

We studied 100 consecutive varus and 100 valgus knees that underwent total or unicompartmental knee arthroplasty. Preoperative CT scans were used to create digitally reconstructed radiography (DRR) images in neutral rotation (NR, parallel to the surgical epicondylar axis), and at 5° and 10° external rotation (ER) and internal rotation (IR). The images were also reconstructed at 10° femoral flexion. The DFVA was evaluated in each DRR image, and the angular variation due to lower limb malposition was investigated.

Results

The DFVA increased as the DRR image shifted from IR to ER, and all angles increased further from extension to 10° flexion. The DFVA variation in each position was 1.3° on average. A larger variation than 2° was seen in 12% of all. Multivariate regression analysis showed that sagittal femoral shaft bowing was independently associated with a large variation of DFVA. Receiver operating characteristic analysis showed that more than 12° of sagittal bowing caused the variation.

Conclusion

If femoral sagittal bowing is more than 12°, close attention should be paid to the lower limb position when taking whole-leg radiographs. Preoperative planning with whole-leg CT data should be considered.

Improved surgical procedure of primary constrained total knee arthroplasty which enables use of the femoral diaphyseal straight extension stem

Background

In performing primary constrained total knee arthroplasties (TKA) to imbalanced knees, the offset stem is sometimes compelled to use, although this is associated with surgical difficulties. We developed a modified procedure which might be able to fit the anteroposterior (AP) and mediolateral (ML) position of the femoral component simultaneously with the straight stem. Purposes of this study were to evaluate usefulness of the modified procedure both in computer simulations and actual surgeries.

Methods

We included 32 knees that had undergone primary TKA using constrained implants because of the coronal imbalance. In the component-first procedure, the distal femur was prepared to fit the AP and ML position of the femoral component simultaneously at first, as in primary TKA. Finally, the stem hole is created based on the femoral component position (the component-first procedure). The femoral component and extension stem were simulated using the three-dimensional planning software (ZedKnee) following the component-first procedure. We investigated the suitability of the straight stem through computer simulation and evaluation of actual surgeries. Clinical and radiographical outcomes were also evaluated at the latest follow-up.

Results

The component-first procedure enabled the AP and ML position of the femoral component to be fitted simultaneously with the straight stem in simulations and actual surgeries in all cases. The stem diameter was not significantly different between simulations and actual surgeries (13.9 and 13.7 mm on average, respectively, p = 0.479) and almost similar from intraclass correlation coefficient analysis (kappa value 0.790). Clinical and radiographical outcomes were almost similar to primary TKA cases and there was no case of component loosening, cortical bone hypertrophy around the stem and stem-tip pain.

Conclusions

Our improved surgical procedure may facilitate use of the constrained implant for more cases of primary TKA in imbalanced knees without the usual surgical difficulties.

Trial registration

Retrospectively registered.

Angular accuracy of plain radiographic measurements in leg alignment: Teleoroentgenogram versus orthoroentgenogram

BACKGROUND

The purpose of the present study was to evaluate the accuracy of the measurements associated with leg alignment on a teleoroentgenogram and an orthoroentgenogram.

METHODS

The models being irradiated were manufactured and represented 10° varus and 15° varus leg alignment, in which the true values of hip-knee-ankle angle (HKAA), mechanical axis (MA) length, and percentage of MA (%MA) were already known. HKAA, MA length, and %MA were measured in various radiographic conditions of the teleoroentgenogram and orthoroentgenogram. Then, the differences between the radiographic measurement values and the corresponding true values were analyzed.

RESULTS

Regarding HKAA, the teleoroentgenogram provided accurate angular measurements with minimal differences between the measurement and true value in both the 10° and 15° varus models, irrespective of the radiographic condition. In the orthoroentgenogram, the modified method measured accurate HKAA; however, the standard method showed significant angular measurement errors with a 0.6° and 1.0° difference from the true value in the 10° and 15° varus models, respectively. This angular measurement error of HKAA in the standard orthoroentgenogram became significantly larger with object-to-image distance. Regarding MA length, the orthoroentgenogram exhibited accurate length measurements. In contrast, the teleoroentgenogram showed a significant length measurement error for the MA length. Regarding %MA, significant differences from the true values of 2.0% and 2.4% were observed in the modified orthoroentgenograms of the 10° and 15° varus models, respectively. The teleoroentgenogram and standard orthoroentgenogram reproduced the accurate measurement value of %MA in the 10° and 15° varus models.

CONCLUSION

A teleoroentgenogram is a reliable modality for accurate angular measurements such as HKAA and %MA. An orthoroentgenogram has the potential to measure both HKAA and length accurately if the radiographic condition was modified; however, measurement error in %MA may occur.

Distinct Roles of Glutamine Metabolism in Benign and Malignant Cartilage Tumors With IDH Mutations

Enchondromas and chondrosarcomas are common cartilage neoplasms that are either benign or malignant, respectively. The majority of these tumors harbor mutations in either IDH1 or IDH2. Glutamine metabolism has been implicated as a critical regulator of tumors with IDH mutations. Using genetic and pharmacological approaches, we demonstrated that glutaminase-mediated glutamine metabolism played distinct roles in enchondromas and chondrosarcomas with IDH1 or IDH2 mutations. Glutamine affected cell differentiation and viability in these tumors differently through different downstream metabolites. During murine enchondroma-like lesion development, glutamine-derived α-ketoglutarate promoted hypertrophic chondrocyte differentiation and regulated chondrocyte proliferation. Deletion of glutaminase in chondrocytes with Idh1 mutation increased the number and size of enchondroma-like lesions. In contrast, pharmacological inhibition of glutaminase in chondrosarcoma xenografts reduced overall tumor burden partially because glutamine-derived non-essential amino acids played an important role in preventing cell apoptosis. This study demonstrates that glutamine metabolism plays different roles in tumor initiation and cancer maintenance. Supplementation of α-ketoglutarate and inhibiting GLS may provide a therapeutic approach to suppress enchondroma and chondrosarcoma tumor growth, respectively. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Smaller Femoral Neck Anteversion in Varus Knees than in Healthy and Valgus Knees

INTRODUCTION

It is important to investigate anatomical differences of the femur and tibia three-dimensionally between varus and valgus knees to enhance surgical approaches and better understand structural factors related to specific patterns of osteoarthritis progression.

MATERIALS AND METHODS

Three-dimensional femoral and tibial bone models were reconstructed from transverse computed-tomography scans in varus osteoarthritis (43 knees), valgus osteoarthritis (40 knees) and healthy (32 knees) groups. Different coordinate systems were defined in each femoral bone model ("Knee" and "Hip" Coordinate System). Femoral neck inclination, lateral bowing, anterior bowing and neck anteversion were measured and compared between Knee and Hip Coordinate Systems. Those parameters were also compared between varus, valgus and healthy groups. The tibial anterior and lateral bowing, external torsion and the fibular axis relative to the tibial mechanical axis were measured and compared between varus and valgus groups.

RESULTS

Femoral neck anteversion was significantly 1-2° greater in the Hip Coordinate System compared to the Knee Coordinate System. Femoral neck anteversion was significantly smaller in varus knees than in healthy or valgus knees, with average difference of approximately 5°. The knee and hip joint are often rotated externally relative to the trunk axis in patients with varus osteoarthritis, perhaps maintaining the geometric relations between pelvis and proximal femur (including peripheral hip muscles) regardless of knee deformities. The fibular axis was inclined slightly valgus and posteriorly in two groups.

CONCLUSIONS

The results may inform hypotheses on, and future studies of, skeletal morphologic development and factors contributing to the progression of knee osteoarthritis. This article is protected by copyright. All rights reserved.

Factors affecting patient satisfaction related to cost and treatment effectiveness in rheumatoid arthritis: results from the multicenter observational cohort study, FRANK Registry

Background

To further improve rheumatoid arthritis (RA) treatment, it is necessary to understand each RA patient’s satisfaction and to identify the factors affecting their satisfaction. Despite the rise in medical costs for RA, little is known about the factors that influence patient satisfaction with the cost of treatment in RA patients.

Methods

This is a multicenter observational study of Japanese RA patients from the FRANK Registry with data analyzed from March 2017 to August 2020. We collected data on demographic characteristics, clinical data, quality of life which was evaluated using the EuroQol 5-dimensional questionnaire (EQ5D), and patient satisfaction. The four categories of patient satisfaction were evaluated individually (i.e., cost, treatment efficacy, activities of daily living [ADL], and global treatment satisfaction). We analyzed the factors that affected each patient’s satisfaction, such as age, sex, EQ5D, disease duration, disease activity, and treatment.

Results

This study included 2235 RA outpatients (406 males, 1829 females). In RA patients, “very satisfied” and “satisfied” were given for nearly half of each satisfaction aspect (cost 49%; efficacy 72%; ADL 58%; global treatment 66%) at the time of the initial registration. To investigate the factors influencing each satisfaction, multivariate analysis has revealed that the use of b/tsDMARDs increased satisfaction of treatment effect (odds ratio [OR] 0.66) and ADL (OR 0.78) but decreased cost satisfaction (OR 2.21). Age (50–64 years; OR 0.91; 65–74 years, 0.55: ≥ 75 years, 0.35), female (OR 0.81), and history of musculoskeletal surgery (OR 0.60) all increased cost satisfaction. Patients with lower disease activity and higher EQ5D scores had higher levels of satisfaction in all areas.

Conclusions

In this study, patient satisfaction in terms of cost, treatment effect, ADL, and overall treatment was generally higher, but some patients were dissatisfied. The cost of satisfaction increased with age and a history of musculoskeletal surgery, while it decreased with a lower EQ5D score and the use of b/tsDMARDs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-022-02746-5.

C10orf10/DEPP activates mitochondrial autophagy and maintains chondrocyte viability in the pathogenesis of osteoarthritis

Osteoarthritis (OA), the most prevalent joint disease, is characterized by the progressive loss of articular cartilage. Autophagy, a lysosomal degradation pathway, maintains cellular homeostasis, and autophagic dysfunction in chondrocytes is a hallmark of OA pathogenesis. However, the cause of autophagic dysfunction in OA chondrocytes remains incompletely understood. Recent studies have reported that decidual protein induced by progesterone (C10orf10/DEPP) positively regulates autophagic functions. In this study, we found that DEPP was involved in mitochondrial autophagic functions of chondrocytes, as well as in OA pathogenesis. DEPP expression decreased in human OA chondrocytes in the absence or presence of pro-inflammatory cytokines, and was induced by starvation, hydrogen peroxide (H₂ O₂ ), and hypoxia (cobalt chloride). For functional studies, DEPP knockdown decreased autophagic flux induced by H₂ O₂ , whereas DEPP overexpression increased autophagic flux and maintained cell viability following H₂ O₂ treatment. DEPP was downregulated by knockdown of forkhead box class O (FOXO) transcription factors and modulated the autophagic function regulated by FOXO3. In an OA mouse model by destabilization of the medial meniscus, DEPP-knockout mice exacerbated the progression of cartilage degradation with TUNEL-positive cells, and chondrocytes isolated from knockout mice were decreased autophagic flux and increased cell death following H₂ O₂ treatment. Subcellular fractionation analysis revealed that mitochondria-located DEPP activated mitochondrial autophagy via BCL2 interacting protein 3. Taken together, our data demonstrate that DEPP is a major stress-inducible gene involved in the activation of mitochondrial autophagy in chondrocytes, and maintains chondrocyte viability during OA pathogenesis. DEPP represents a potential therapeutic target for enhancing autophagy in patients with OA.

TGFβ1 signaling protects chondrocytes against oxidative stress via FOXO1-autophagy axis

OBJECTIVE

The forkhead box O1 (FOXO1) transcription factor is a key regulator of autophagy. In chondrocytes, reduced FOXO1 expression with aging causes osteoarthritis due to dysfunction of autophagy, but the mechanisms underlying regulation of FOXO1 expression and the reduction in expression with aging remain unclear. We investigated the mechanism by which transforming growth factor β1 (TGFβ1) signaling regulates the FOXO1-autophagy axis.

METHODS

Expression of FOXO1 was measured in chondrocytes after TGFβ1 treatment. Immunohistochemistry was performed to estimate the levels of activin receptor-like kinase 5 (ALK5) and FOXO1 in the knee joints of young, middle-aged and old mice. The effects of the ALK5 inhibitor and SMAD3 or SMAD2 knockdown on FOXO1 expression were evaluated. The role of TGFβ1 in autophagy after hydrogen peroxide (H₂O₂) treatment was analyzed. The protective effect of TGFβ1 against H₂O₂ treatment was assessed by cell viability assay and TUNEL assay.

RESULTS

TGFβ1 promoted the expression of FOXO1 mRNA and protein. Both ALK5 and FOXO1 expression decreased with aging. ALK5 inhibition and SMAD3 knockdown suppressed induction of FOXO1 expression by TGFβ1, whereas SMAD2 knockdown increased it. TGFβ1 promoted the expression of microtubule-associated proteins 1A/1B light chain 3B (LC3)-I protein via the SMAD3-FOXO1 pathway. Furthermore, under H₂O₂ treatment, TGFβ1 promoted expression of LC3-II. TGFβ1 pretreatment suppressed cell death of chondrocytes following H₂O₂ treatment, but this protective effect was abolished by FOXO1 knockdown.

CONCLUSIONS

TGFβ1 protects chondrocytes against oxidative stress via the FOXO1-autophagy axis, and a reduction in ALK5 expression might cause reduced FOXO1 expression with aging.

Frequency and risk factor analyses of bone erosion of the distal interphalangeal joint in patients with rheumatoid arthritis: a cross-sectional study

AIMS

Few reports have focused on the distal interphalangeal (DIP) joint in patients with rheumatoid arthritis (RA). The purposes of this study were to evaluate the frequency of bone erosion of the DIP joint, and to determine the factors associated with its deformity.

METHODS

This study reviewed 204 patients with RA in whom radiographs of hands were obtained. According to the presence/absence of bone erosion of the DIP joint, patients were divided into two groups (DIP-positive and DIP-negative groups). Additionally, wrist, metacarpal phalangeal (MP), thumb interphalangeal (IP), and proximal interphalangeal (PIP) joints were evaluated. Clinical variables such as age, sex, body mass index, disease duration, disease activity (DAS28-CRP), and drug use were investigated.

RESULTS

Regarding the radiological findings of the DIP joint, 32 patients (15.7%) were allocated to the DIP-positive group and 172 patients (84.3%) to the DIP-negative group. The mean age, disease duration, DAS28-CRP, and the rate of corticosteroids usage were significantly higher in the DIP-positive than in the DIP-negative group (p = 0.0031, 0.0062, 0.0342, and 0.0011, respectively). Radiologically, concomitant bone erosions of the wrist, MP, thumb IP, and PIP joints were significantly more common in the DIP-positive than in the DIP-negative group (p < 0.01 for all four joints). Multivariate analysis demonstrated that advanced age, long disease duration, and the presence of radiological bone erosion of the PIP joint were independently associated with bone erosion of the DIP joint (p = 0.0480, 0.0307, and 0.0021, respectively). Accordingly, in patients with DIP erosions, mean DAS28-CRP was significantly higher in patients with <5 years (n = 10) than in those with ≥5 years of disease duration (n = 22, p = 0.0088).

CONCLUSIONS

Bone erosion can be observed at the DIP joint in patients with RA, and these cases frequently shows bone erosions of other finger joints, such as PIP joint. In addition, bone erosion can be observed soon after the onset of RA caused by uncontrolled disease activity in some patients with RA.

Malrotation of whole-leg radiograph less than 10 degrees does not influence preoperative planning in open-wedge high tibial osteotomy

Coronal whole-leg radiography is generally used for preoperative open-wedge high tibial osteotomy (OWHTO) planning. Nevertheless, malrotational whole-leg radiographs could affect the planning, and the effects could possibly be strengthened by the knee flexed position. Consecutive 51 varus osteoarthritis knees that underwent OWHTO were included. The digitally reconstructed radiography (DRR) images parallel to the surgical epicondylar axis (neutral rotation; NR), 5° and 10° external rotation (ER) or internal rotation (IR), were reconstructed from preoperative CT. Preoperative weight-bearing line percentage (WBL%), medial proximal tibial angle (MPTA), planned opening angle, and planned postoperative MPTA were measured with OWHTO planning in each DRR image. Correlations among the measured differences relative to NR images and knee flexion angle were investigated. As the DRR image shifted from ER to IR, the differences in preoperative WBL% and MPTA gradually increased, whereas those in the opening angle gradually decreased, although all differences in the opening angle were within 0.5° on an average. Opening angle differences remarkably correlated with knee flexion angle, and knees with >10° flexion contracture had >1° difference in 10° ER or IR images. Planned postoperative MPTA had relatively high consistency regardless of whole-leg malrotation. The opening angle measurement using malrotated radiographs less than 10° would be clinically reliable in cases without knee flexion contracture. Nevertheless, extreme care should be taken in cases with >10° knee flexion contracture. The MPTA after medial opening would be a consistent and reliable parameter in whole-leg alignment evaluation.

Does Preparation of the Subtalar Joint for Primary Union Affect Clinical Outcome in Patients Undergoing Intramedullary Nail for Rheumatoid Arthritis of the Hindfoot and Ankle?

This study aimed to evaluate whether preparation of the subtalar joint affects the clinical outcomes after tibiotalocalcaneal arthrodesis using an intramedullary nail with fins for rheumatoid ankle/hindfoot deformity. Fifty-three joints in 51 patients who underwent tibiotalocalcaneal arthrodesis using an intramedullary nail with fins for rheumatoid arthritis at 2 institutions were included. Ten patients were male and 41 were female, with a mean age at surgery and follow-up period of 61.3 years and 71.6 months, respectively. Radiographic bone union was evaluated at the most recent visit. Univariate and multivariable analyses were performed to determine the risk factors associated with nonunion. The mean postoperative Japanese Society for Surgery of the Foot ankle/hindfoot scale was 65.3 (range, 5-84). The tibiotalar nonunion rate was 0%, whereas the subtalar nonunion rate was 43.3% (23 joints). Revision surgery was performed in 5, all of which were due to painful subtalar nonunion. Absence of subtalar curettage and earlier postoperative weightbearing were significantly associated with subtalar nonunion (p = .0451 and p = .0438, respectively). Subtalar nonunion after tibiotalocalcaneal arthrodesis for rheumatoid hindfoot is associated with higher revision rate. To decrease the risk of subtalar nonunion after tibiotalocalcaneal arthrodesis with an intramedullary nail in rheumatoid patients, curettage for the subtalar joint should be performed, and full weightbearing should be delayed until at least 26 days postoperatively.

Autoreactivity of Peripheral Helper T Cells in the Joints of Rheumatoid Arthritis

Autoreactive CD4 T cells are thought to play pivotal roles in the pathogenesis of rheumatoid arthritis (RA). Recently, a subset of CD4 T cells that express high levels of programmed death-1 (PD-1) but are distinct from follicular helper T cells have been identified in the joints of RA patients and named peripheral helper T (Tph) cells. Because PD-1 is expressed on T cells chronically stimulated with the Ags, we tested a hypothesis that Tph cells are the pathogenic autoreactive CD4 T cells in RA. We found that human Tph cells in RA joints produce proinflammatory effector cytokines, including IFN-γ, TNF-α, and GM-CSF, in addition to B cell-helping cytokines, such as IL-21 and CXCL13. Flow cytometric analysis showed different bias of TCR Vβ usage between PD-1^high Tph cells and PD-1^low/neg CD4 T cells, including Th1 cells, in the joint or memory CD4 T cells in the peripheral blood, whereas there was little difference between the latter two subsets. In line with this, deep sequencing of TCR demonstrated an overlap of expanded clones between peripheral blood memory CD4 T cells and PD-1^low/neg CD4 T cells but not Tph cells in the joint. Interestingly, Tph cells preferentially exhibited autologous MLR in vitro, which required recognition of self-MHC class II and was pronounced by blocking PD-1 signaling. Taken together, these results suggest that Tph cells are the pathogenic autoreactive CD4 T cells in RA, which expand locally in the joints and are regulated by PD-1 signaling.

Prognostic factors for the short-term mortality of patients with rheumatoid arthritis admitted to intensive care units

Background

Patients with rheumatoid arthritis (RA) have high mortality risk and are frequently treated in intensive care units (ICUs).

Methods

This was a retrospective observational study. This study included 67 patients (20 males, 47 females) with RA who were admitted at the ICU of our institution for ≥48 h between January 2008 and December 2017. We analyzed the 30-day mortality of these patients and the investigated prognostic factors in RA patients admitted to our ICU.

Results

Upon admission, the median age was 70 (range, 33–96) years, and RA duration was 10 (range, 0–61) years. The 5-year survival after ICU admission was 47%, and 30-day, 90-day, and 1-year mortality rates were 22, 27, and 37%, respectively. The major reasons for ICU admission were cardiovascular complications (24%) and infection (40%) and the most common ICU treatments were mechanical ventilation (69%), renal replacement (25%), and vasopressor (78%). In the 30-day mortality group, infection led to a fatal outcome in most cases (67%), and nonsurvival was associated with a significantly higher glucocorticoid dose, updated Charlson’s comorbidity index (CCI), and acute physiology and chronic health evaluation (APACHE) II score. Laboratory data obtained at ICU admission showed that lower platelet number and total protein and higher creatinine and prothrombin time international normalized ratio (PT-INR) indicated significantly poorer prognosis. The multivariate Cox proportional hazard model revealed that nonuse of csDMARDs, high updated CCI, increased APACHE II score, and prolonged PT-INR were associated with a higher risk of mortality after ICU admission.

Conclusion

Our study demonstrated that the nonuse of csDMARDs, high updated CCI, elevated APACHE II score, and coagulation abnormalities predicted poorer prognosis in RA patients admitted to the ICU.

Patient-specific prediction of joint line convergence angle after high tibial osteotomy using a whole-leg radiograph standing on lateral-wedge insole

PURPOSE

To assess the usefulness of a whole-leg radiograph standing on lateral-wedge insole (LWI) for predicting the change in joint line convergence angle (JLCA) before vs. after high tibial osteotomy (HTO).

METHODS

Forty knees with medial osteoarthritis underwent open-wedge HTO. Pre-operatively, all patients had whole-leg radiographs taken in three different conditions: supine, standing, and standing on LWI inclined at 20°. A standing whole-leg radiograph was also obtained post-operatively. Radiological measurements including JLCA and percentage of mechanical axis (%MA) were compared. Using pre-operative radiographs, correction angles were calculated with the target %MA at 62.5%. Correlations between the difference in calculated correction angle among the three pre-operative conditions and the change in JLCA before vs. after HTO were assessed.

RESULTS

In the pre-operative standing conditions, the mean JLCA of 3.8° was significantly decreased to 3.2° using LWI, which did not differ from post-operative JLCA of 3.1°. Mean %MA significantly shifted laterally from 20.6 to 24.8% using LWI, and was strongly correlated with the change in JLCA (coefficient, 0.83). Calculated correction angles differed significantly among the three pre-operative conditions. The difference in calculated correction angle between standing with and without LWI was strongly correlated to the change in standing JLCA before vs. after HTO (coefficient, 0.73).

CONCLUSION

Larger differences in calculated correction angles between pre-operative radiographs standing with and without LWI predicted larger changes in JLCA after HTO. Whole-leg radiograph standing on LWI is a promising modality for correct pre-operative planning considering patient-specific changes in JLCA before vs. after HTO.

LEVEL OF EVIDENCE

IV.

Tracing Tumor Evolution in Sarcoma Reveals Clonal Origin of Advanced Metastasis

Cellular heterogeneity is frequently observed in cancer, but the biological significance of heterogeneous tumor clones is not well defined. Using multicolor reporters and CRISPR-Cas9 barcoding, we trace clonal dynamics in a mouse model of sarcoma. We show that primary tumor growth is associated with a reduction in clonal heterogeneity. Local recurrence of tumors following surgery or radiation therapy is driven by multiple clones. In contrast, advanced metastasis to the lungs is driven by clonal selection of a single metastatic clone (MC). Using RNA sequencing (RNA-seq) and in vivo assays, we identify candidate suppressors of metastasis, namely, Rasd1, Reck, and Aldh1a2. These genes are downregulated in MCs of the primary tumors prior to the formation of metastases. Overexpression of these suppressors of metastasis impair the ability of sarcoma cells to colonize the lungs. Overall, this study reveals clonal dynamics during each step of tumor progression, from initiation to growth, recurrence, and distant metastasis.

GRK5 Inhibition Attenuates Cartilage Degradation via Decreased NF-κB Signaling

OBJECTIVE

NF-κB-dependent signaling is an important modulator in osteoarthritis (OA), and G protein-coupled receptor kinase 5 (GRK5) regulates the NF-κB pathway. This study was undertaken to investigate the functional involvement of GRK5 in OA pathogenesis.

METHODS

GRK5 expression in normal and OA human knee joints was analyzed immunohistochemically. Gain- or loss-of-function experiments were performed using human and mouse chondrocytes. OA was induced in GRK5-knockout mice by destabilization of the medial meniscus, and histologic examination was performed. OA was also induced in wild-type mice, which were then treated with an intraarticular injection of amlexanox, a selective GRK5 inhibitor, every 5 days for 8 weeks.

RESULTS

GRK5 protein expression was increased in human OA cartilage. In vitro, expression levels of OA-related factors and NF-κB transcriptional activation were down-regulated by suppression of the GRK5 gene in human OA chondrocytes (3.49-fold decrease in IL6 [P < 0.01], 2.43-fold decrease in MMP13 [P < 0.01], and 2.66-fold decrease in ADAMTS4 [P < 0.01]). Conversely, GRK5 overexpression significantly increased the expression of OA-related catabolic mediators and NF-κB transcriptional activation. On Western blot analysis, GRK5 deletion reduced IκBα phosphorylation (up to 4.4-fold decrease [P < 0.05]) and decreased p65 nuclear translocation (up to 6.4-fold decrease [P < 0.01]) in mouse chondrocytes. In vivo, both GRK5 deletion and intraarticular amlexanox protected mouse cartilage against OA.

CONCLUSION

Our results suggest that GRK5 regulates cartilage degradation through a catabolic response mediated by NF-κB signaling, and is a potential target for OA treatment. Furthermore, amlexanox may be a major compound in relevant drugs.

The influence of post-operative knee coronal alignment parameters on long-term patient-reported outcomes after closed-wedge high tibial osteotomy

Background

Both intra-articular and extra-articular knee alignment pathologies can affect clinical outcomes after high tibial osteotomy. The purpose of this study was to investigate post-operative knee coronal alignment parameters that affect long-term patient-reported outcomes after closed-wedge high tibial osteotomy (CW-HTO).

Methods

This study included 105 osteoarthritic knees that underwent CW-HTO. Long-term patient-reported outcomes were defined by the 2011 Knee Society Score (KSS) and were collected at an average follow-up of 10.2 years. Post-operative knee coronal alignment parameters, consisting of the femoral tibial angle (FTA), lateral distal femoral angle (LDFA), medial proximal tibial angle (MPTA), tibial plateau inclination (TPI), and joint line convergence angle (JLCA), were measured using standing radiographs of the knee at an average follow-up of 11.0 months. The correlations between these parameters and KSS were then assessed by Spearman's correlation analysis. Comparisons of groups classified by MPTA and TPI cutoff values were performed by the Wilcoxon rank-sum test.

Results

Post-operative JLCA showed a significant negative correlation with two KSS sub-scores: satisfaction (R = -0.2232, P = 0.022) and total function (R = -0.2059, P = 0.035). There was no significant difference in any KSS sub-score between the "low" groups (MPTA and TPI less than 95 and 5°, respectively) and the "high" groups (MPTA and TPI greater than 98 and 7°, respectively).

Conclusions

Among knee coronal alignment parameters, a large post-operative residual JLCA, which is an intra-articular varus deformity, was independently associated with worsened long-term clinical outcomes after CW-HTO.

Level of evidence

Level Ⅳ, Retrospective cohort study.

Influence of dioxin-related compounds on physical function in Yusho incident victims

Purpose

Few studies have examined the influence of dioxin-related compounds on human physical function, and existing results are inconsistent. In 1968, accidental human exposure to rice oil contaminated with dioxin-related compounds resulted in the development of Yusho oil disease in Japan. We aimed to determine whether the degree of exposure to dioxin-related compounds was associated with physical function in Yusho patients.

Methods

In 2016, 65 men (average age: 65.7 years) and 77 women (average age: 64.7 years) participated in a nationwide health examination in Fukuoka prefecture. Functional reach, gait speed, hand grip strength, and toe grip strength were evaluated as part of physical function. The serum levels of polychlorinated dibenzo-p-dioxin, polychlorinated dibenzofurans, and non-ortho polychlorinated biphenyls were measured using high-resolution gas chromatography and high-resolution mass spectrometry. We examined the association between physical function tests and serum toxic equivalency (TEQ) values.

Results

A 10-fold increase in serum TEQ levels was negatively associated with functional reach (adjusted b = -4.07, p = 0.017) and hand grip strength (adjusted b = -2.20, p = 0.0245) in men. No association was observed between serum TEQ level and physical function in women.

Conclusion

Our findings suggest that dioxin-related compounds have a negative influence on physical function in men. However, these findings should be interpreted carefully. Future studies examining additional data on musculoskeletal disorders are warranted.

FOXO1 transcription factor regulates chondrogenic differentiation through transforming growth factor β1 signaling

The forkhead box O (FOXO) proteins are transcription factors involved in the differentiation of many cell types. Type II collagen (Col2) Cre-Foxo1-knockout and Col2-Cre-Foxo1,3,4 triple-knockout mice exhibit growth plate malformation. Moreover, recent studies have reported that in some cells, the expressions and activities of FOXOs are promoted by transforming growth factor β1 (TGFβ1), a growth factor playing a key role in chondrogenic differentiation. Here, using a murine chondrogenic cell line (ATDC5), mouse embryos, and human mesenchymal stem cells, we report the mechanisms by which FOXOs affect chondrogenic differentiation. FOXO1 expression increased along with chondrogenic differentiation, and FOXO1 inhibition suppressed chondrogenic differentiation. TGFβ1/SMAD signaling promoted expression and activity of FOXO1. In ATDC5, FOXO1 knockdown suppressed expression of sex-determining region Y box 9 (Sox9), a master regulator of chondrogenic differentiation, resulting in decreased collagen type II α1 (Col2a1) and aggrecan (Acan) expression after TGFβ1 treatment. On the other hand, chemical FOXO1 inhibition suppressed Col2a1 and Acan expression without suppressing Sox9 To investigate the effects of FOXO1 on chondrogenic differentiation independently of SOX9, we examined FOXO1's effects on the cell cycle. FOXO1 inhibition suppressed expression of p21 and cell-cycle arrest in G₀/G₁ phase. Conversely, FOXO1 overexpression promoted expression of p21 and cell-cycle arrest. FOXO1 inhibition suppressed expression of nascent p21 RNA by TGFβ1, and FOXO1 bound the p21 promoter. p21 inhibition suppressed expression of Col2a1 and Acan during chondrogenic differentiation. These results suggest that FOXO1 is necessary for not only SOX9 expression, but also cell-cycle arrest during chondrogenic differentiation via TGFβ1 signaling.

Intracellular cholesterol biosynthesis in enchondroma and chondrosarcoma

Enchondroma and chondrosarcoma are the most common benign and malignant cartilaginous neoplasms. Mutations in isocitrate dehydrogenase 1 and 2 (IDH1/2) are present in the majority of these tumors. We performed RNA-seq analysis on chondrocytes from Col2a1Cre;Idh1LSL/+ animals and found that genes implied in cholesterol synthesis pathway were significantly upregulated in the mutant chondrocytes. We examined the phenotypic effect of inhibiting intracellular cholesterol biosynthesis on enchondroma formation by conditionally deleting SCAP (sterol regulatory element-binding protein cleavage-activating protein), a protein activating intracellular cholesterol synthesis, in IDH1 mutant mice. We found fewer enchondromas in animals lacking SCAP. Furthermore, in chondrosarcomas, pharmacological inhibition of intracellular cholesterol synthesis significantly reduced chondrosarcoma cell viability in vitro and suppressed tumor growth in vivo. Taken together, these data suggest that intracellular cholesterol synthesis is a potential therapeutic target for enchondromas and chondrosarcomas.

Intracellular biosynthesis of lipids and cholesterol by Scap and Insig in mesenchymal cells regulates long bone growth and chondrocyte homeostasis

During enchondral ossification, mesenchymal cells express genes regulating the intracellular biosynthesis of cholesterol and lipids. Here, we have investigated conditional deletion of Scap or of Insig1 and Insig2 (Scap inhibits intracellular biosynthesis and Insig proteins activate intracellular biosynthesis). Mesenchymal condensation and chondrogenesis was disrupted in mice lacking Scap in mesenchymal progenitors, whereas mice lacking the Insig genes in mesenchymal progenitors had short limbs, but normal chondrogenesis. Mice lacking Scap in chondrocytes showed severe dwarfism, with ectopic hypertrophic cells, whereas deletion of Insig genes in chondrocytes caused a mild dwarfism and shortening of the hypertrophic zone. In vitro studies showed that intracellular cholesterol in chondrocytes can derive from exogenous and endogenous sources, but that exogenous sources cannot completely overcome the phenotypic effect of Scap deficiency. Genes encoding cholesterol biosynthetic proteins are regulated by Hedgehog (Hh) signaling, and Hh signaling is also regulated by intracellular cholesterol in chondrocytes, suggesting a feedback loop in chondrocyte differentiation. Precise regulation of intracellular biosynthesis is required for chondrocyte homeostasis and long bone growth, and these data support pharmacological modulation of cholesterol biosynthesis as a therapy for select cartilage pathologies.

Summary: Conditional deletion of genes that regulate intracellular cholesterol biosynthesis in mesenchymal cells or chondrocytes shows that precise regulation of biosynthesis is required for chondrocyte homeostasis and long bone growth.

Hedgehog inhibits β-catenin activity in synovial joint development and osteoarthritis

Both the WNT/β-catenin and hedgehog signaling pathways are important in the regulation of limb development, chondrocyte differentiation, and degeneration of articular cartilage in osteoarthritis (OA). It is not clear how these signaling pathways interact in interzone cell differentiation and synovial joint morphogenesis. Here, we determined that constitutive activation of hedgehog signaling specifically within interzone cells induces joint morphological changes by selectively inhibiting β-catenin-induced Fgf18 expression. Stabilization of β-catenin or treatment with FGF18 rescued hedgehog-induced phenotypes. Hedgehog signaling induced expression of a dominant negative isoform of TCF7L2 (dnTCF7L2) in interzone progeny, which may account for the selective regulation of β-catenin target genes observed. Knockdown of TCF7L2 isoforms in mouse chondrocytes rescued hedgehog signaling-induced Fgf18 downregulation, while overexpression of the human dnTCF7L2 orthologue (dnTCF4) in human chondrocytes promoted the expression of catabolic enzymes associated with OA. Similarly, expression of dnTCF4 in human chondrocytes positively correlated with the aggrecanase ADAMTS4. Consistent with our developmental findings, activation of β-catenin also attenuated hedgehog-induced or surgically induced articular cartilage degeneration in mouse models of OA. Thus, our results demonstrate that hedgehog inhibits selective β-catenin target gene expression to direct interzone progeny fates and articular cartilage development and disease. Moreover, agents that increase β-catenin activity have the potential to therapeutically attenuate articular cartilage degeneration as part of OA.

CCAAT/enhancer-binding protein β promotes receptor activator of nuclear factor-kappa-B ligand (RANKL) expression and osteoclast formation in the synovium in rheumatoid arthritis

INTRODUCTION

CCAAT/enhancer-binding protein β (C/EBPβ) is a transcription factor that is activated in the synovium in rheumatoid arthritis (RA) and promotes expression of various matrix metalloproteinases. In this study, we examined whether C/EBPβ mediates the expression of receptor activator of nuclear factor-kappa-B ligand (RANKL) and drives osteoclast formation in primary fibroblast-like synoviocytes (FLS) from RA patients. The cooperation of C/EBPβ and activation transcription factor-4 (ATF4) in the regulation of the RANKL promoter was also investigated.

METHODS

Immunofluorescence staining was performed for C/EBPβ, RANKL, and ATF4 in synovium from RA patients. Adenovirus expression vectors for two major isoforms, C/EBPβ-liver-enriched activator protein (LAP) and - liver-enriched inhibitory protein (LIP), or small interfering RNA for C/EBPβ, were used to manipulate C/EBPβ expression in RA-FLS. RA-FLS over-expressing C/EBPβ were co-cultured with peripheral blood mononuclear cells (PBMCs) to test osteoclast formation by tartrate-resistant acid phosphatase (TRAP) staining. A promoter assay for RANKL, a chromatin immunoprecipitation (ChIP) assay and an immunoprecipitation (IP) assay were also performed.

RESULTS

Immunofluorescence staining showed colocalization of C/EBPβ, ATF4 and RANKL in RA synovium. Western blotting revealed the expression of C/EBPβ-LAP and -LIP in RA-FLS. Over-expression of either C/EBPβ-LAP or -LIP significantly increased the expression of RANKL mRNA, while C/EBPβ-LIP down-regulated osteoprotegerin (OPG) mRNA. The RANKL/OPG mRNA ratio was significantly increased by C/EBPβ-LIP over-expression. Knockdown of C/EBPβ with siRNA decreased the expression of RANKL mRNA. The number of TRAP-positive multinucleated cells was increased in co-cultures of PBMCs and FLS over-expressing either C/EBPβ-LAP or -LIP, but was more significant with LIP. C/EBPβ-LIP does not have a transactivation domain. However, promoter assays showed that C/EBPβ-LIP and ATF4 synergistically transactivate the RANKL promoter. ChIP and IP assays revealed the cooperative binding of C/EBPβ and ATF4 on the RANKL promoter.

CONCLUSIONS

We demonstrated that C/EBPβ, especially C/EBPβ-LIP in cooperation with ATF4, is involved in osteoclast formation by regulating RANKL expression in RA-FLS. These findings suggest that C/EBPβ plays a crucial role in bone destruction in RA joints.

GRP78 clustering at the cell surface of neurons transduces the action of exogenous alpha-synuclein

Mutation or multiplication of the alpha-synuclein (Syn)-encoding gene is frequent cause of early onset Parkinson's disease (PD). Recent evidences point to the pathogenic role of excess Syn also in sporadic PD. Syn is a cytosolic protein, which has been shown to be released from neurons. Here we provide evidence that extracellular Syn induces an increase in surface-exposed glucose-related protein of 78 kDa (GRP78), which becomes clustered in microdomains of the neuronal plasma membrane. Upon interacting with Syn, GRP78 activates a signaling cascade leading to cofilin 1 inactivation and stabilization of microfilaments, thus affecting morphology and dynamics of actin cytoskeleton in cultured neurons. Downregulation of GRP78 abolishes the activity of exogenous Syn, indicating that it is the primary target of Syn. Inactivation of cofilin 1 and stabilization of actin cytoskeleton are present also in fibroblasts derived from genetic PD patients, which show a dramatic increase in stress fibers. Similar changes are displayed by control cells incubated with the medium of PD fibroblasts, only when Syn is present. The accumulation of Syn in the extracellular milieu, its interaction with the plasma membrane and Syn-driven clustering of GRP78 appear, therefore, responsible for the dysregulation of actin turnover, leading to early deficits in synaptic function that precede neurodegeneration.

CCAAT/enhancer binding protein β regulates expression of Indian hedgehog during chondrocytes differentiation

Background

CCAAT/enhancer binding protein β (C/EBPβ) is a transcription factor that promotes hypertrophic differentiation of chondrocytes. Indian hedgehog (Ihh) also stimulates the hypertrophic transition of chondrocytes. Furthermore, runt-related transcription factor-2 (RUNX2) was reported to regulate chondrocyte maturation during skeletal development and to directly regulate transcriptional activity of Ihh. In this study, we investigated whether the interaction of C/EBPβ and RUNX2 regulates the expression of Ihh during chondrocyte differentiation.

Methodology/Results

Immunohistochemistry of embryonic growth plate revealed that both C/EBPβ and Ihh were strongly expressed in pre-hypertrophic and hypertrophic chondrocytes. Overexpression of C/EBPβ by adenovirus vector in ATDC5 cells caused marked stimulation of Ihh and Runx2. Conversely, knockdown of C/EBPβ by lentivirus expressing shRNA significantly repressed Ihh and Runx2 in ATDC5 cells. A reporter assay revealed that C/EBPβ stimulated transcriptional activity of Ihh. Deletion and mutation analysis showed that the C/EBPβ responsive element was located between −214 and −210 bp in the Ihh promoter. An electrophoretic mobility shift assay (EMSA) and a chromatin immunoprecipitation (ChIP) assay also revealed the direct binding of C/EBPβ to this region. Moreover, reporter assays demonstrated that RUNX2 failed to stimulate the transcriptional activity of the Ihh promoter harboring a mutation at the C/EBPβ binding site. EMSA and ChIP assays showed that RUNX2 interacted to this element with C/EBPβ. Immunoprecipitation revealed that RUNX2 and C/EBPβ formed heterodimer complex with each other in the nuclei of chondrocytes. These data suggested that the C/EBPβ binding element is also important for RUNX2 to regulate the expression of Ihh. Ex vivo organ culture of mouse limbs transfected with C/EBPβ showed that the expression of Ihh and RUNX2 was increased upon ectopic C/EBPβ expression.

Conclusions

C/EBPβ and RUNX2 cooperatively stimulate expression of Ihh through direct interactions with a C/EBPβ binding element, which further promotes hypertrophic differentiation of chondrocytes during the chondrocyte differentiation process.

Expression of myeloperoxidase in acute myeloid leukemia blasts mirrors the distinct DNA methylation pattern involving the downregulation of DNA methyltransferase DNMT3B

Myeloperoxidase (MPO) has been associated with both a myeloid lineage commitment and favorable prognosis in patients with acute myeloid leukemia (AML). DNA methyltransferase inhibitors (decitabine and zeburaline) induced MPO gene promoter demethylation and MPO gene transcription in AML cells with low MPO activity. Therefore, MPO gene transcription was directly and indirectly regulated by DNA methylation. A DNA methylation microarray subsequently revealed a distinct methylation pattern in 33 genes, including DNA methyltransferase 3 beta (DNMT3B), in CD34-positive cells obtained from AML patients with a high percentage of MPO-positive blasts. Based on the inverse relationship between the methylation status of DNMT3B and MPO, we found an inverse relationship between DNMT3B and MPO transcription levels in CD34-positive AML cells (P=0.0283). In addition, a distinct methylation pattern was observed in five genes related to myeloid differentiation or therapeutic sensitivity in CD34-positive cells from AML patients with a high percentage of MPO-positive blasts. Taken together, the results of the present study indicate that MPO may serve as an informative marker for identifying a distinct and crucial DNA methylation profile in CD34-positive AML cells.

CCAAT/enhancer-binding protein β regulates the repression of type II collagen expression during the differentiation from proliferative to hypertrophic chondrocytes

CCAAT/enhancer-binding protein β (C/EBPβ) is a transcription factor that promotes hypertrophic differentiation by stimulating type X collagen and matrix metalloproteinase 13 during chondrocyte differentiation. However, the effect of C/EBPβ on proliferative chondrocytes is unclear. Here, we investigated whether C/EBPβ represses type II collagen (COL2A1) expression and is involved in the regulation of sex-determining region Y-type high mobility group box 9 (SOX9), a crucial factor for transactivation of Col2a1. Endogenous expression of C/EBPβ in the embryonic growth plate and differentiated ATDC5 cells were opposite to those of COL2A1 and SOX9. Overexpression of C/EBPβ by adenovirus vector in ATDC5 cells caused marked repression of Col2a1. The expression of Sox9 mRNA and nuclear protein was also repressed, resulting in decreased binding of SOX9 to the Col2a1 enhancer as shown by a ChIP assay. Knockdown of C/EBPβ by lentivirus expressing shRNA caused significant stimulation of these genes in ATDC5 cells. Reporter assays demonstrated that C/EBPβ repressed transcriptional activity of Col2a1. Deletion and mutation analysis showed that the C/EBPβ core responsive element was located between +2144 and +2152 bp within the Col2a1 enhancer. EMSA and ChIP assays also revealed that C/EBPβ directly bound to this region. Ex vivo organ cultures of mouse limbs transfected with C/EBPβ showed that the expression of COL2A1 and SOX9 was reduced upon ectopic C/EBPβ expression. Together, these results indicated that C/EBPβ represses the transcriptional activity of Col2a1 both directly and indirectly through modulation of Sox9 expression. This consequently promotes the phenotypic conversion from proliferative to hypertrophic chondrocytes during chondrocyte differentiation.

Towards excimer-laser-based stereolithography: a rapid process to fabricate rigid biodegradable photopolymer scaffolds

We demonstrate high-resolution photocross-linking of biodegradable poly(propylene fumarate) (PPF) and diethyl fumarate (DEF) using UV excimer laser photocuring at 308 nm. The curing depth can be tuned in a micrometre range by adjusting the total energy dose (total fluence). Young's moduli of the scaffolds are found to be a few gigapascal, high enough to support bone formation. The results presented here demonstrate that the proposed technique is an excellent tool for the fabrication of stiff and biocompatible structures on a micrometre scale with defined patterns of high resolution in all three spatial dimensions. Using UV laser photocuring at 308 nm will significantly improve the speed of rapid prototyping of biocompatible and biodegradable polymer scaffolds and enables its production in a few seconds, providing high lateral and horizontal resolution. This short timescale is indeed a tremendous asset that will enable a more efficient translation of technology to clinical applications. Preliminary cell tests proved that PPF : DEF scaffolds produced by excimer laser photocuring are biocompatible and, therefore, are promising candidates to be applied in tissue engineering and regenerative medicine.

CCAAT/enhancer binding protein β regulates expression of matrix metalloproteinase-3 in arthritis

Objectives

To investigate whether CCAAT/enhancer binding protein β (C/EBPβ) mediates the expression of matrix metalloproteinase-3 (MMP-3) and aggrecanases in arthritis.

Methods

Localisation of C/EBPβ and MMP-3 in synovium and cartilage from patients with rheumatoid arthritis and osteoarthritis was determined by immunohistochemistry. Cell lines SW982, C28/I2 and human fibroblast-like synoviocytes stimulated by interleukin 1β (IL-1β) were subjected to western blotting and quantitative PCR. Overexpression of C/EBPβ by adenovirus was performed in cells and organ culture of normal cartilage. Knockdown of C/EBPβ by small interference RNA was performed in cells. Activity of the human MMP-3 and aggrecanase-2 ADAMTS-5 (a disintegrin and metalloproteinase with thrombospondin motifs) promoters was analysed by a luciferase assay. To determine whether C/EBPβ directly binds to the MMP-3 or ADAMTS-5 promoter,a chromatin immunoprecipitation assay was performed.

Results

Immunohistochemistry showed that C/EBPβ and MMP-3 were co-localised in arthritic synovium and cartilage. Western blots revealed increased C/EBPβ expression in cells treated with IL-1β. Expression of MMP-3, MMP-13 and ADAMTS-5 mRNA was significantly increased by the overexpression of C/EBPβ. C/EBPβ stimulated MMP-3 expression and induced matrix degradation in cartilage explants. C/EBPβ knockdown reduced MMP-3 and ADAMTS-5 expression. C/EBPβ stimulated the 2011 bp MMP-3 promoter and the 1768 bp ADAMTS-5 promoter in a dose-dependent manner. Deletion and mutation analysis of the MMP-3 promoter showed that the C/EBPβ core responsive element was located between −108 bp and −100 bp. The chromatin immunoprecipitation assay showed that C/EBPβ was directly bound to MMP-3 and ADAMTS-5 promoters.

Conclusions

These data demonstrate that C/EBPβ is involved in expression of MMP-3 and ADAMTS-5 in arthritic synovium and cartilage.

Evaluation of cartilage degradation in arthritis using T1ρ magnetic resonance imaging mapping

T1ρ magnetic resonance imaging (MRI) can be used to map proteoglycan (PG) loss in cartilage. Here, we used T1ρ MRI to map cartilage degradation in osteoarthritis (OA) and rheumatoid arthritis (RA). Tissue samples were obtained from five RA patients and 14 OA patients following total knee arthroplasty (TKA). Three parameters were measured: First, macroscopic grading of cartilage sample tissues was performed on a 5-grade scale (G0: normal, G1: swelling, G2: superficial fibrillation, G3: deep fibrillation, G4: subchondral bone exposure). Second, semi-quantitative values of PG were assessed by measuring the optical density of Safranin-O-stained paraffin sections that had been digitally photographed. Third, cartilage was divided into superficial and deep layers and the T1ρ values were quantified. T1ρ values of OA and RA in the superficial layers showed significant differences between groups (G0/1 and G0/2 for OA; G0/2 and G1/2 for RA). In the deep layers, T1ρ values of OA and RA also differed significantly between groups. In both the superficial and deep layers, there was a significant correlation between the mean T1ρ values and macroscopic grading (P < 0.01 for OA, P < 0.001 for RA). We found a negative correlation between the score of Safranin-O staining and T1ρ values (r = -0.61 for OA, r = -0.79 for RA). In addition, RA subjects had significantly higher T1ρ values than OA subjects of similar morphologic grade. In conclusion, T1ρ MRI is able to detect and map the early stages of cartilage degradation in OA and RA. This method is reliable and useful for the evaluation of macromolecular changes in arthritic cartilage.

Human herpes virus 8-negative primary effusion lymphoma with BCL6 rearrangement in a patient with idiopathic CD4 positive T-lymphocytopenia

Primary effusion lymphoma (PEL) was initially designated as a body-cavity-based lymphoma and recognized as a distinct clinical entity without a contiguous tumor mass. PEL was first reported in patients with acquired immunodeficiency syndrome (AIDS) and the distinctive feature of PEL originally reported as a B-cell neoplasm characterized by infection of the tumor cells by human herpes virus 8 (HHV-8). However, there have recently been several reports of PEL in patients without human immunodeficiency virus (HIV) or HHV-8 infection.

Expression of myeloperoxidase enhances the chemosensitivity of leukemia cells through the generation of reactive oxygen species and the nitration of protein

Myeloperoxidase (MPO), a pivotal lineage marker for acute myeloid leukemia (AML), has been also shown to have a prognostic value: a high percentage of MPO-positive blasts correlates to favorable prognosis. To understand the relationship between the expression of MPO in leukemia cells and the response to chemotherapeutic agents, we established MPO-expressing K562 leukemia cell lines and then treated them with cytosine arabinocide (AraC). Cells expressing wild-type MPO, but not mutant MPO that could not mature, died earlier of apoptosis than control K562 cells. Reactive oxygen species (ROS) were generated more in leukemia cells expressing MPO, and the generation was abrogated by MPO inhibitors or antioxidants. Tyrosine nitration of cellular protein also increased more in MPO-expressing K562 cells than control cells after treatment with AraC. In clinical samples, CD34-positive AML cells from high-MPO cases showed a tendency to be sensitive to AraC in the colony-formation assay, and the generation of ROS and the nitration of protein were observed only when the percentage of MPO-expressing cells was high. These data suggest that MPO enhances the chemosensitivity of AML through the generation of ROS and the nitration of proteins.