Expression of Apelin in Rotator Cuff Tears and Examination of Its Regulatory Mechanism: A Translational Study.

OBJECTIVES: Inflammatory mediators play important roles in the pain associated with rotator cuff tears (RCTs), but their underlying mechanisms are unclear. Apelin, a neuropeptide, is upregulated under inflammatory conditions and possibly contributes to pain induced by rotator cuff tears. This translational study aimed to examine apelin expression and regulation by tumor necrosis factor alpha (TNF-α) in patients with RCT and in rat RCT models. METHODS: Synovial tissues were harvested from the glenohumeral joints of the shoulders in 46 patients who underwent arthroscopic Bankart repair for recurrent shoulder dislocations (RSDs) or arthroscopic rotator cuff repair for RCTs. The harvested tissues were extracted and processed by reverse transcriptase-polymerase chain reaction (RT-PCR). Rats underwent sham or RCT surgery; the rotator cuff tissues were extracted 1, 7, 14, 28, and 56 days after surgery and analyzed for mRNA expression levels of the TNF-α and apelin using RT-PCR. The cultured rotator cuff cells (RCCs) were stimulated with TNF-α to examine their role in the regulation of apelin expression. RESULTS: Apelin expression was higher in the RCT group than in the RSD group and significantly correlated with pain intensity. In rats, the expression was also higher in RCT. Apelin expression significantly increased during the acute and chronic phases in rats. CONCLUSIONS: In cultured RCCs, apelin mRNA levels significantly increased after TNF-α stimulation. Apelin levels were regulated by TNF-α and were highly expressed in patients with RCT and rats in RCT models. Thus, apelin may be a new pain management target for RCTs.

Tenodesis with bone marrow venting under local anesthesia for recalcitrant lateral epicondylitis: results of 2 years of follow-up.

Hypothesis: We hypothesized that the treatment of recalcitrant lateral epicondylitis requires accurate identification of the painful area to promote remodeling of the degenerated extensor insertion and to stabilize the tendon origin during tendon healing. Thus, we performed tenodesis with bone marrow venting under local anesthesia for recalcitrant lateral epicondylitis. Methods: Twenty patients (21 elbows) were treated with bone marrow venting at the painful area of the lateral epicondyle of the elbow and tenodesis using 2 soft anchors lateral to the capitellum (immediately distal to the painful area) and were followed up for ≥2 years. Patients were assessed using the numerical rating scale for pain and the Quick Disabilities of the Arm, Shoulder, and Hand questionnaire, and objective evaluation included active range of motion. Results: The mean preoperative and postoperative pain scores were 7.5 and 0.5, respectively, indicating significant pain relief (P < .001). The mean preoperative and postoperative Quick Disabilities of the Arm, Shoulder, and Hand questionnaire scores were 44.2 and 1.0, respectively (P < .001). Two elbows had a slightly positive Thomsen test at the final visit. No recurrence of intra-articular symptoms induced by synovial fringe impingement was observed. Patients experienced more pain at the bone-tendon junction of extensors than at the tendon parenchyma. Conclusion: Tenodesis with bone marrow venting under local anesthesia was effective for subjective patient satisfaction and positive clinical outcomes at ≥2 years of follow-up in patients with recalcitrant lateral epicondylitis. Intra-articular symptoms can be improved by stabilization of the lateral soft tissue without treatment for intra-articular lesions.

Increased nerve growth factor expression in the synovial tissues of patients with rotator cuff tears.

BACKGROUND: Rotator cuff tears (RCTs) are often associated with severe shoulder pain. Non-steroidal anti-inflammatory drugs, not recommended for long-term use, do not effectively manage RCT-induced pain, resulting in reduced quality of life. To improve management, a better understanding of the fundamental properties of RCT pain is needed. Here, we aimed to compare the expression levels of nerve growth factor (NGF) and cyclooxygenase-2 (COX-2) mRNA in the synovial tissues of patients with RCT-induced pain and patients with non-painful recurrent shoulder dislocation (RSD). METHODS: The study included 32 patients with RCT who underwent arthroscopic rotator cuff repair and 28 patients with non-painful RSD who underwent arthroscopic Bankart repair. Synovial tissue samples were harvested from subacromial bursa and rotator interval of RCT patients and from the rotator interval of RSD patients. Samples were analyzed quantitatively expression levels for NGF and COX2 mRNA and NGF protein. RESULTS: NGF mRNA and protein levels were significantly higher in the rotator interval of RCT patients than in the rotator interval of RSD patients (p = 0.0017, p = 0.012, respectively), while COX2 mRNA levels did not differ significantly between the two patient groups. In RCT patients, COX2 mRNA was more highly expressed in the rotator interval than in the subacromial bursa (p = 0.038), whereas the mRNA and protein levels of NGF did not differ between the two tissues. The expression of NGF mRNA in the synovium of the rotator interval was significantly correlated with the numeric rating scale of pain (ρ = 0.38, p = 0.004). CONCLUSION: NGF mRNA and protein levels were elevated in patients with painful RCT compared with those in patients with non-painful RSD, whereas COX-2 levels were comparable in the two patient groups. These findings provide insights into novel potential strategies for clinical management of RCT.

Limitation of the external glenohumeral joint rotation is associated with subacromial impingement syndrome, especially pain.

BACKGROUND: Subacromial impingement syndrome is a common disorder associated with functional impairment and disability of the shoulder. Internal/external glenohumeral rotation is important for shoulder function. However, because it is difficult to measure the glenohumeral joint rotation angle physically, the relationship between this angle and the clinical symptoms of subacromial impingement syndrome is still largely unknown. Using advanced cine-magnetic resonance imaging techniques, we designed a study to improve our understanding of the nature of this relationship. METHODS: We evaluated 100 shoulders with subacromial impingement syndrome. Patients underwent cine-magnetic resonance imaging during axial rotation with the arm adducted. During imaging, patients rotated their shoulder from maximum internal rotation to maximum external rotation over 10 seconds and then to maximum internal rotation over 10 seconds. The rotation angles were then evaluated using a series of axial images. The Constant-Murley (Constant) and UCLA scores for each patient were determined, and the correlation between the scores and rotational angles was assessed. Patients were divided into 3 groups according to the Constant pain score, and the rotational angles of each group were compared. Rotational angles were also compared between shoulders with and without night pain. RESULTS: The external rotation angle showed a significant but low correlation with the Constant and UCLA scores (ρ = 0.24 and 0.24, respectively), whereas the internal rotation angle did not. In comparing the pain groups of Constant score and UCLA score, the external rotation angle significantly decreased as pain increased (P < .01), demonstrating a negative correlation (ρ = -0.47, -0.41, respectively). Additionally, the shoulders of patients with night pain showed significantly more restriction of external rotation angles than the shoulders of those without night pain (P = .01). CONCLUSIONS: Limitation of the glenohumeral joint's external rotation is correlated with pain, for which we explore possible explanations. The results suggest that night pain can be effectively reduced using therapeutic interventions that target external rotational dysfunction.

Comparison of glenohumeral joint rotation between asymptomatic subjects and patients with subacromial impingement syndrome using cine-magnetic resonance imaging: a cross-sectional study.

BACKGROUND: The purpose of this study to compare glenohumeral joint motion during active shoulder axial rotation between subacromial impingement syndrome (SIS) shoulders and asymptomatic shoulders using cine-magnetic resonance imaging (cine-MRI). Measurement of glenohumeral joint motion via manual intervention does not assess the usual glenohumeral joint motion, and the glenoid surface cannot be confirmed manually. However, cine-MRI can produce clear images of glenohumeral joint rotation. Therefore, we sought to measure the active ROM of the glenohumeral rotation using cine-MRI. METHODS: Seventy-three shoulders in 42 asymptomatic volunteers and 110 SIS shoulders in 103 consecutive patients were included in this study. We evaluated 36 matched pairs (72 shoulders in total) adjusting for baseline characteristics with propensity score matching method. The patients underwent cine-MRI during axial rotation of the adducted arm. During imaging, participants rotated their shoulder from the maximum internal rotation to the maximum external rotation over the first 10 s and then back to the maximum internal rotation over the subsequent 10 s. We assessed internal/external rotation, and compared the asymptomatic and SIS shoulders in this regard. Evaluation of rotation angles was performed on a series of axial images through the humeral head center. RESULTS: The mean internal rotation angles of the asymptomatic and patient groups were 55° ± 10° and 41° ± 23°, respectively, (P = .002; 95% Confidence Interval [CI], 51-58 vs 33-49); the mean external rotation angles were 47° ± 15° and 21° ± 25°, respectively, (P < .001; CI, 42-52 vs 13-29). CONCLUSIONS: Compared to asymptomatic shoulders, SIS shoulders showed significantly restricted glenohumeral rotation as determined by cine-MRI. Our results suggested that the significant limitation of active glenohumeral rotation might be associated with rotator cuff dysfunction.

IL-1ß mediates NGF and COX-2 expression through transforming growth factor-activating kinase 1 in subacromial bursa cells derived from rotator cuff tear patients.

BACKGROUND: Increased interleukin (IL)-1ß expression in the subacromial bursa (SAB) is associated with severe pain in rotator cuff tears (RCTs). Additionally, transforming growth factor (TGF)-ß-activated kinase 1 (TAK1) is essential for cytokine-mediated cascades. TAK1 also regulates the expression of pain-associated molecules such as cycloxygenase-2 (COX-2) and nerve growth factor (NGF) in synovial fibroblasts; however, this regulation in the SAB is not fully understood. METHODS: SAB samples were harvested from 18 subjects with RCTs. The expression and localization of NGF and COX-2 was determined using polymerase chain reaction (PCR) analysis and immunohistochemistry. Regulation of COX-2 and NGF by IL-1ß in subacromial bursa cells (SABCs) was investigated by culturing and stimulating SABCs with vehicle control (culture medium), 50 ng/ml recombinant human IL-1ß (rhIL1-ß), 50 ng/ml rhIL-1ß and 10 µM celecoxib (COX-2 inhibitor), or 10 µM prostaglandin E2 (PGE2) for 24 h. The effects of TAK1 inhibition on rhIL-1ß stimulation were determined by culturing and treating SABCs with control, 50 ng/ml rhIL-1ß, or 50 ng/ml rhIL-1ß and 10 µM (5Z)-7-oxozeaenol (TAK1 inhibitor) for 24 h. NGF and COX-2 mRNA expression was monitored using quantitative PCR. RESULTS: COX-2 and NGF mRNA expression was observed in all SAB specimens. Immunohistochemical analysis showed that COX-2-positive cells were in the lining and sublining layers. NGF-positive cells were observed in the sublining layer. rhIL-1ß treatment significantly increased NGF and COX-2 mRNA levels compared with control cells. The COX-2 inhibitor did not suppress rhIL-1ß-induced NGF expression, and PGE2 stimulation did not alter NGF mRNA expression. In contrast, the TAK1 inhibitor significantly reduced rhIL-1ß-stimulated COX-2 and NGF mRNA expression. CONCLUSION: IL-1ß regulates the expression of NGF and COX-2, pain-related molecules in the SAB, through TAK1. Therefore, TAK1 may be one potential therapeutic target for reducing pain in patients with RCTs.

Nerve growth factor continuously elevates in a rat rotator cuff tear model.

BACKGROUND: Nerve growth factor (NGF) plays a key role in osteoarthritic pain and low back pain. Rotator cuff tear (RCT) is often associated with severe shoulder pain. However, the role of NGF in RCT remains to be fully understood. METHODS: Rats were divided into sham and RCT groups. The rotator cuff was harvested from the sham and RCT groups on various days for reverse transcription-polymerase chain reaction analysis of Tnfa, Ngf, Il1b, and Cox2 expression. Rotator cuffs from the sham and RCT groups were also harvested at 1 and 14 days for enzyme-linked immunosorbent assay and immunohistochemistry to assess NGF protein levels and localization. Rotator cuff-derived cells were stimulated with rat recombinant tumor necrosis factor (TNF)-α to investigate the involvement of TNF-α in the regulation of NGF expression. RESULTS: Tnfa and Ngf messenger RNA levels increased within 1 day in the RCT group. Notably, Tnfa and Ngf upregulation persisted for up to 56 days after the RCT surgery, while Il1b and Cox2 expression was significantly reduced. NGF levels in the RCT group were significantly higher than those in the sham operation group on days 1 and 14. Certain inflammatory cells and synovial-like cells lining the surface of the laminated tears were NGF-positive on days 1 and 14, respectively. Ngf messenger RNA levels increased significantly in rotator cuff-derived cells after TNF-α stimulation. CONCLUSION: NGF levels are continuously elevated in RCT, which is mainly regulated by TNF-α. NGF may thus represent a potential target for therapies that modulate RCT pain.

Electromyographic analysis of infraspinatus and scapular muscles during external shoulder rotation with different weight loads and positions.

BACKGROUND: Strengthening the infraspinatus is important in shoulder rehabilitation. Changes in infraspinatus activity with changing load and position have not been quantified. We sought to determine the most appropriate load and posture for early infraspinatus strengthening by assessing for changes in electromyographic activity in the healthy infraspinatus and other shoulder girdle muscles during isometric external rotational exercise under different loads with the shoulder adducted in the supine and seated positions. METHODS: Sixteen healthy adults (30 shoulders) performed isometric shoulder external rotation in the sitting and supine positions, starting with the shoulder and forearm in neutral position and the elbow flexed 90°. Loads (0.5 kg, 1 kg, and 2 kg) were applied at rest. We assessed the infraspinatus, upper trapezius, posterior deltoid, and biceps brachii. For analysis, we used the mean percentage of maximum voluntary muscle contraction (%MVC) value measured during each isometric contraction divided by the maximum voluntary muscle contraction (MVC) of each muscle. RESULTS: In the infraspinatus and posterior deltoid, significant interaction was observed between body position and load. Compared to the sitting position, an increase in activity in the supine position was attenuated as load increased, especially at 2 kg. The supine values of the upper trapezius and biceps brachii were always significantly lower than those in the sitting position regardless of load. CONCLUSION: The activity of the infraspinatus can be increased gradually during rehabilitation by beginning in the supine position, which assures low activity of the upper trapezius and biceps brachii. Exercise with the shoulder adducted in the supine position can strengthen the infraspinatus gradually and avoid compensatory mobility. LEVEL OF EVIDENCE: Level 3.

In Vivo Release of Vancomycin from Calcium Phosphate Cement.

Calcium phosphate cement (CPC) has good release efficiency and has therefore been used as a drug delivery system for postoperative infection. The release profile of CPC has mainly been evaluated by in vitro studies, which are carried out by immersing test specimens in a relatively large amount of solvent. However, it remains unclear whether antibiotic-impregnated CPC has sufficient clinical effects and release in vivo. We examined the in vivo release profile of CPC impregnated with vancomycin (VCM) and compared this with that of polymethylmethacrylate (PMMA) cement. To evaluate the release profile in vitro, the test specimens were immersed in 10 mL sterile phosphate-buffered saline per gram of test specimen and incubated at 37°C for 56 days in triplicate. For in vivo experiments, the test specimens were implanted between the fascia and muscle of the femur of rats. Residual VCM was extracted from the removed test specimens to determine the amount of VCM released into rat tissues. CPC released more VCM over a longer duration than PMMA in vitro. Released levels of VCM from CPC/VCM in vivo were 3.4-fold, 5.0-fold, and 8.6-fold greater on days 1, 7, and 28, respectively, than those released on the corresponding days from PMMA/VCM and were drastically greater on day 56 due to inefficient release from PMMA/VCM. The amount of VCM released from CPC and PMMA was much higher than the minimum inhibitory concentration (1.56 µg) and lower than the detection limit, respectively. Our findings suggest that CPC is a suitable material for releasing antibiotics for local action against established postoperative infection.

Relationship between synovial inflammatory cytokines and progression of osteoarthritis after hip arthroscopy: Experimental assessment.

PURPOSE: Synovial membrane inflammation is the most commonly presenting finding during hip arthroscopy and may have a role in the pathomechanism of hip osteoarthritis (OA). The aim of this study was to determine the relationship between synovial cytokine levels and progression of OA after hip arthroscopy. METHODS: We prospectively examined 20 patients (20 hips) who underwent arthroscopic hip surgery. For all patients, radiographs and severity of pain were evaluated preoperatively. During arthroscopy, we harvested a sample of the synovial membrane and determined the levels of six typical inflammatory cytokines with real-time polymerase chain reaction. We compared the levels of these cytokines in patients who showed OA progression and non-progression after hip arthroscopy. RESULTS: Although the average age of patients who showed OA progression postoperatively tended to be higher, there were no significant differences in characteristics involving clinical assessment between patients who showed OA progression and those who showed non-progression. Intraoperative tumour necrosis factor α (TNFα) expression was significantly higher in patients who showed OA progression postoperatively ( p = 0.042). CONCLUSIONS: Elevation of TNFα level might be a predictor of OA progression after hip arthroscopy.

Macrophage-derived inflammatory cytokines regulate growth factors and pain-related molecules in mice with intervertebral disc injury.

Upregulation of inflammatory cytokines and various growth factors is a significant contributor to discogenic low back pain. The aim of this study was to investigate possible regulation of pain-related molecules by macrophages and the role of macrophage-derived molecules in injured intervertebral disc (IVD)s. C57BL/6J mice were used in this study. We characterized the expression profiles of genes for tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, nerve growth factor (NGF), and vascular endothelial growth factor (VEGF) in both intact and injured IVDs. We examined whether macrophage depletion, induced by systemic injection of clodronate-laden liposomes, affected the expression of these molecules in injured IVDs. The effect of TNF-alpha on cultured F4/80-CD11b-cells in injured IVDs was investigated. Expression of TNF-alpha and IL-1beta was significantly increased in injured IVDs, but decreased by macrophage depletion. Expression of NGF and VEGF was also significantly increased, but by contrast was not decreased by macrophage depletion. TNF-alpha treatment of F4/80-cells from injured IVDs upregulated NGF, VEGF, cyclooxygenase (COX)-2, and microsomal prostaglandin E synthase-1 (mPGES1). IVD injury upregulated inflammatory cytokines and various growth factors. Macrophages in the injured IVDs produced inflammatory cytokines, but not growth factors. Macrophage-derived inflammatory cytokines regulate growth factors and pain-related molecules. These findings demonstrate further complexity in the pathogenesis of discogenic pain. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.

Three-dimensional full-scale bone modeling for preoperative simulation of surgery in patients with elbow contractures due to bone deformities.

It is often difficult to treat for elbow contractures by malformation of bones. We planned a mobilization of elbow with using three-dimensional full-scale bone modeling. We found it was effective to use it in preoperative planning because we could recognize the elements of contractures in every deformity.

Transforming growth factor activating kinase 1 regulates extracellular matrix degrading enzymes and pain-related molecule expression following tumor necrosis factor-α stimulation of synovial cells: an in vitro study.

BACKGROUND: Recent studies have suggested that the tumor necrosis factor-α (TNF-α) pathway is a potential target for the management of osteoarthritis (OA). Transforming growth factor (TGF)-ß-activated kinase 1 (TAK1) is essential in several cytokine-mediated cascades, including the TNF-α, interleukin-1 (IL-1), and TGF-ß pathways. The role of TAK1 in synovial tissue in OA is not fully understood. Using synovial cells harvested from OA patients during surgery, we investigated whether TAK1 inhibition suppresses production of TNF-α-induced extracellular matrix degrading enzymes and expression of pain-related molecules. METHODS: Synovial tissues were harvested from ten subjects with radiographic evidence of osteoarthritis (OA) during total knee arthroplasty. Synovial cells were cultured and stimulated with control (culture media), 10 ng/mL human recombinant TNF-α, or 10 ng/mL TNF-α and 10 µM of the TAK1 inhibitor (5Z)-7-oxozeaenol for 24 h. Real-time polymerase chain reaction (PCR) analysis was used to monitor expression of mRNA of the extracellular matrix degrading enzymes matrix metalloproteinase-3 (MMP-3) and a disintegrin-like and metalloprotease (reprolysin type) with thrombospondin type 1 motif, 4 (ADAMTS-4); and of the pain-related molecules cyclooxygenase-2 (COX-2), microsomal prostaglandin E synthase-1 (mPGES-1), and nerve growth factor (NGF). MMP-3 and NGF protein concentrations in cell supernatant were measured by enzyme-linked immunosorbent assay (ELISA). COX-2, mPGES-1 and ADAMTS-4 protein expression was also evaluated by western blotting. RESULTS: TNF-α stimulated increases in ADAMTS-4 and MMP3 mRNA (2.0-fold and 1.6-fold, respectively, p < 0.05) and protein expression (21.5-fold and 2.0-fold, respectively). Treatment with the TAK1 inihibitor (5Z)-7-oxozeaenol reduced ADAMTS-4 and MMP3 mRNA (0.5-fold and 0.6-fold, respectively) and protein expression (1.4-fold and 0.5-fold, respectively) in OA synovial cells. COX-2, mPGES-1 and NGF mRNA (11.2-fold, 3.1-fold and 2.7-fold, respectively) and protein expression (3.0-fold, 2.7-fold and 2.2-fold, respectively) were increased by TNF-α. (5Z)-7-oxozeaenol treatment reduced mPGES1 and NGF mRNA (1.5-fold and 0.8-fold, respectively) and protein (1.5-fold and 0.5-fold, respectively). CONCLUSION: TAK1 plays an important role in the regulation of TNF-α induced extracellular matrix degrading enzymes and pain-related molecule expression. TAK1 may be a potential target for therapeutic strategies aimed at preventing osteoarthritis progression and pain.

The cytokine expression in synovial membrane and the relationship with pain and pathological findings at hip arthroscopy.

BACKGROUND: Synovial membrane inflammation is the most common finding presenting during hip arthroscopy, and may play a role in hip pain. We sought to determine the relationships between synovial cytokine levels, hip pain, and arthroscopic findings of the hip joint. METHODS: We prospectively included 33 patients who underwent arthroscopic hip surgery (34 hips). For all patients, radiographs and severity of pain were evaluated preoperatively. During arthroscopy, we classified the chondral injury and synovitis, noted the incidence of labral tear and its instability, and a sample of the synovial membrane was harvested for quantitative PCR to determine levels of TNFα, IL1ß, IL6, ADAMTS4, MMP1, and MMP3. The relationships between the levels of these cytokines, severity of hip pain, and the pathological findings during arthroscopy were examined. RESULTS: Pain intensity and cytokine levels were not significantly different between patients with labral tear or instability and those without. By contrast, the expression of TNFα, IL1ß, IL6, and MMP1 mRNA was significantly higher in patients with diffuse synovitis than in patients with focal synovitis. VAS score during rest showed significant positive correlation with IL6 (r = 0.45, p < 0.01), while VAS score on walking showed a positive correlation with TNFα (r = 0.47, p < 0.01), and ADAMTS4 (r = 0.51, p < 0.01). The modified Harris Hip pain score showed a negative correlation with TNFα (r = -0.38, p = 0.04) and IL6 (r = -0.58, p < 0.01). CONCLUSIONS: The severity of synovitis and chondral injury are considered to be more important in the pathology of hip pain than labral tear or instability. Inflammatory cytokines, especially TNFα and IL6 might play an important role in the pathogenesis of pain in patients indicated for hip arthroscopy, possibly depending on the severity of synovitis.