The subacromial bursa modulates tendon healing after rotator cuff injury in rats

Rotator cuff injuries result in more than 500,000 surgeries annually in the United States, many of which fail. These surgeries typically involve repair of the injured tendon and removal of the subacromial bursa, a synovial-like tissue that sits between the rotator cuff and the acromion. The subacromial bursa has been implicated in rotator cuff pathogenesis and healing. Using proteomic profiling of bursa samples from nine patients with rotator cuff injury, we show that the bursa responds to injury in the underlying tendon. In a rat model of supraspinatus tenotomy, we evaluated the bursa's effect on the injured supraspinatus tendon, the uninjured infraspinatus tendon, and the underlying humeral head. The bursa protected the intact infraspinatus tendon adjacent to the injured supraspinatus tendon by maintaining its mechanical properties and protected the underlying humeral head by maintaining bone morphometry. The bursa promoted an inflammatory response in injured rat tendon, initiating expression of genes associated with wound healing, including Cox2 and Il6. These results were confirmed in rat bursa organ cultures. To evaluate the potential of the bursa as a therapeutic target, polymer microspheres loaded with dexamethasone were delivered to the intact bursae of rats after tenotomy. Dexamethasone released from the bursa reduced Il1b expression in injured rat supraspinatus tendon, suggesting that the bursa could be used for drug delivery to reduce inflammation in the healing tendon. Our findings indicate that the subacromial bursa contributes to healing in underlying tissues of the shoulder joint, suggesting that its removal during rotator cuff surgery should be reconsidered.

Epigallocatechin-3-gallate suppresses pain-related and proinflammatory mediators in the subacromial bursa in rotator cuff tendinopathy

Rotator cuff tendinopathy is one of the leading causes of shoulder pain. However, the mechanisms involved in the development of rotator cuff tendinopathy pain are not fully understood. In this study, we first examined the histological features of subacromial bursa from patients with rotator cuff tendinopathy who had symptoms of pain, and investigated the expression of pain mediators, proinflammatory cytokines, metalloproteinases, growth factors, and alarmins in diseased tendon and bursa tissue by real-time PCR, western blot, and/or immunohistochemistry/immunofluorescence staining. Then we investigated whether epigallocatechin-3-gallate (EGCG) could reduce the expression of pain mediators and proinflammatory cytokines in human primary bursa cells and explored the paracrine effect of these EGCG-treated bursa cells on tenocytes in vitro. Neovascularization and infiltration of immune cells including monocytes/macrophages and mast cells were observed in diseased bursa tissue. Bursa from patients with pain had higher mRNA expression of pain mediators and proinflammatory cytokines, compared to the rotator cuff tendon of the same patients, as well as the bursa from asymptomatic patients. EGCG treatment significantly suppressed the interleukin 1 beta (IL-1β)-induced elevation of mRNA expression of pain mediators, proinflammatory cytokines, and matrix metalloproteinases (MMPs) in bursa cells in vitro; conditioned medium from EGCG-treated bursa cells significantly reduced IL-1β-induced expression in human primary tenocytes. Our study suggests that the subacromial bursa might serve as a local source of pain mediators and proinflammatory cytokines in rotator cuff tendinopathy. Moreover, EGCG treatment by primarily targeting the subacromial bursa may be a potential strategy to relieve rotator cuff tendinopathy-related pain and symptoms.

Increased expression of type 1 cannabinoid (CB1) receptor among patients with rotator cuff lesions and shoulder stiffness

BACKGROUND

Shoulder stiffness is a disease manifested by pain, limited range of motion, and functional disability. The inflammatory and fibrosis processes play a substantial role in the pathogenesis of shoulder stiffness. The CB1 receptor has been recognized to mediate the processes of pathologic fibrosis. This study investigated the role of the CB1 pathway in pathogenesis of rotator cuff lesions with shoulder stiffness.

METHODS

All of the patients undergoing repair surgery for rotator cuff lesions were recruited and subcategorized into subjects with and without shoulder stiffness. Reverse transcription-polymerase chain reaction assay was used to evaluate the expression level of CB1 and interleukin 1β (IL-1β) in the subacromial bursae, and enzyme-linked immunosorbent assay was used to measure the concentration of CB1 and IL-1β in the subacromial fluid. Tenocytes treated with CB1 agonists and antagonists were also studied for the relationship of CB1 and the inflammatory cytokine IL-1β.

RESULTS

The patients with shoulder stiffness had higher messenger RNA (mRNA) expression (P = .040) and immunohistochemistry staining (P < .001) of CB1 in the subacromial bursa and higher CB1 concentration in the subacromial fluid (P = .008). Tenocytes treated with the CB1 agonist WIN 55,212-2 and antagonist AM251 showed increased expression of IL-1β mRNA (P = .049) and suppressed expression of IL-1β mRNA (P = .001), respectively.

DISCUSSION

The CB1 pathway is involved in the pathogenesis of shoulder stiffness. It may be a promising target for the treatment of rotator cuff lesions with shoulder stiffness.

Increased substance P expression in the trochanteric bursa of patients with greater trochanteric pain syndrome

Greater trochanteric pain syndrome (GTPS) is a pathology that can involve the trochanteric bursa or the tendons which attach to the greater trochanter. To clarify the potential importance of bursa versus tendon pathology and of substance P (SP) in contributing to pain in this condition tendon and bursa tissue biopsies were obtained from 34 patients with GTPS and 29 control subjects. Specimens were evaluated via light microscopy for histopathological and morphological differences, as well as using immunohistochemistry for macrophages (CD68), inflammatory cells (CD45) and SP. Bursa [stroma score, mean (SD): 4.18 (1.65) vs. 2.53 (1.61), p = 0.051] and tendon [Bonar score, mean (SD): GTPS mean (SD) 12.65 (2.0), control (10.43 (4.84), p = 0.04] from subjects with GTPS demonstrated more extensive signs of pathology than specimens from control subjects. There was a significantly greater presence of SP in the bursa (frequency: 9/12 vs. 6/16, p = 0.047), but not in the tendon (8/12 vs. 8/15, p = 0.484) of subjects with GTPS compared to controls. An increased presence of SP in the trochanteric bursa may be related to the pain associated with GTPS.

Expression of bioactive bone morphogenetic proteins in the subacromial bursa of patients with chronic degeneration of the rotator cuff

Degeneration of the rotator cuff is often associated with inflammation of the subacromial bursa and focal mineralization of the supraspinatus tendon. Portions of the supraspinatus tendon distant from the insertion site could transform into fibrous cartilage, causing rotator-cuff tears owing to mechanical instability. Indirect evidence is presented to link this pathology to ectopic production and secretion of bioactive bone morphogenetic proteins (BMPs) from sites within the subacromial bursa. Surgically removed specimens of subacromial bursa tissue from patients with chronic tears of the rotator cuff were analyzed by immunohistochemistry and reverse transcription-PCR. Bioactive BMP was detected in bursa extracts by a bioassay based on induction of alkaline phosphatase in the osteogenic/myogenic cell line C2C12. Topical and differential expression of BMP-2/4 and BMP-7 mRNA and protein was found in bursa tissue. The bioassay of C2C12 cells revealed amounts of active BMP high enough to induce osteogenic cell types, and blocking BMP with specific antibodies or soluble BMP receptors Alk-3 and Alk-6 abolished the inductive properties of the extract. Sufficient information was gathered to explain how ectopic expression of BMP might induce tissue transformation into ectopic bone/cartilage and, therefore, promote structural degeneration of the rotator cuff. Early surgical removal of the subacromial bursa might present an option to interrupt disease progression.

Stromal cell-derived factor 1 (SDF-1, CXCL12) is increased in subacromial bursitis and downregulated by steroid and nonsteroidal anti-inflammatory agents

Several studies have demonstrated that inflammation in the subacromial bursa is an important component in the pathogenesis of impingement syndrome. We have demonstrated in a previous study that many inflammatory cytokines, including stromal cell-derived factor 1 (SDF-1, CXCL12), are increased in the subacromial bursa [Blaine et al. 2005. J Shoulder Elbow Surg 14(Suppl 1):84S-89S]. SDF-1 is a potent chemotactic and angiogenic factor that stimulates recruitment of inflammatory cells. In the current study, we proposed that the resident cells in subacromial bursal tissue produce SDF-1, which can play a role in the inflammatory reponse of bursal tissue, and that this chemokine can be regulated by steroid (dexamethasone) and nonsteroidal anti-inflammatory medications (NSAIDs). Twenty-two subacromial bursa tissues (18 bursitis and 4 normal bursa) were obtained intraoperatively from patients during shoulder surgery and analyzed using the cDNA Array technique in accordance with an IRB approved protocol. cDNA array results were confirmed with real-time reverse transcription-polymerase chain reaction (RT-PCR). Bursal cells (from 4 normal bursa, 3 bursitis) and two normal bone marrow with whole tissue explants were cultured for one passage. Cell culture supernatants were collected and SDF-1 protein was detected with enzyme-linked immunosorbent assay (ELISA). Cultured bursal cells were treated with a COX-2 inhibitor and dexamethasone, and cells was harvested at 1-day and 4-day intervals. SDF-1 expression was evaluated by real-time RT-PCR and ELISA. cDNA Array analysis demonstrated that the gene expression of SDF-1 was increased in patients with subacromial bursitis compared to controls (p < 0.05). Real-time RT-PCR also revealed that the mRNA expression of SDF-1 in bursitis tissue is increased 10-fold over control tissue. While the normal bursal cells produced negligible amounts of SDF-1 protein, cultured cells derived from bursitis lesion released as much SDF-1 protein (235 pg/100,000 cells) as normal bone marrow stromal cells (283 pg/100,000 cells) as measured by ELISA. The addition of a COX-2 inhibitor and dexamethasone to bursitis cell lines led to decreased SDF-1 expression levels compared to untreated bursitis cell lines. These studies demonstrate that there is a significant elevation of SDF-1 expression in the subacromial bursa of patients with rotator cuff disease. Furthermore, this chemokine can be downregulated by COX-2 inhibitors and steroids. These results provide biologic evidence for the use of steroid and NSAIDs in the treatment of subacromial bursitis. In the future, targeted inhibition of molecules such as SDF-1 in the subacromial bursa may present a therapeutic strategy that may avoid the side effects of these other (steroid and NSAID) medications.

Matrix molecule mRNA levels in the bursa and rotator cuff of patients with full-thickness rotator cuff tears

PURPOSE

The purpose of this study was to evaluate at the mRNA level a subset of extracellular matrix molecules relevant during healing and remodeling of rotator cuff tears.

TYPE OF STUDY

Controlled laboratory study.

METHODS

Bursal and rotator cuff tissue from the margin of the rotator cuff tear were harvested from 10 patients (mean age, 57.5 +/- 7.3 years) undergoing surgical repair of full-thickness rotator cuff tears. There were six male and four female patients with a mean duration of symptoms of 14.6 months (range, 2 to 60 months). The mean tear size was 4.4 cm. In addition, tissue was obtained from 6 cadaveric specimens with no gross evidence of rotator cuff tearing. Reverse transcription polymerase chain reaction (RT-PCR) was performed for type I, II, and III collagen, biglycan, decorin, and aggrecan, and normalized to the housekeeping gene GAPDH.

RESULTS

RT-PCR showed that both the bursa and rotator cuff margin had increased mRNA levels for type I and type III collagen in patients with full-thickness rotator cuff tears when compared with normal cadaveric controls. In addition, there was a significant decrease in decorin mRNA levels and an increase in aggrecan mRNA levels in the rotator cuff margin of torn rotator cuff tendons when compared with normal cadaveric controls.

CONCLUSIONS

These results suggest that both the bursa and rotator cuff margin of patients with rotator cuff tears are actively remodeling after injury and that both tissues may potentially contribute to the healing process following repair.

CLINICAL RELEVANCE

These findings may help clinicians determine what aspects of the repair process can be manipulated to affect optimal ruptured tendon repair.

Tendon healing in vitro: genetic modification of tenocytes with exogenous PDGF gene and promotion of collagen gene expression

PURPOSE

Promotion of collagen production can increase tendon healing strength and reduce repair ruptures. Transfer of an exogenous growth factor gene to tenocytes of intrasynovial tendons may enhance the capacity of cells to produce collagen. We transferred the platelet-derived growth factor B (PDGF-B) gene to tenocytes and investigated its effects on the expression of the PDGF gene and the type I collagen gene in an in vitro tenocyte culture model.

METHODS

Tenocytes obtained from explant cultures of rat intrasynovial tendons were treated for 12 hours with the plasmid containing the PDGF complementary deoxyribonucleic acid (cDNA) with liposome and were then cultured for 6 additional days. The control tenocytes did not receive the exogenous gene and liposome. Efficiency of the gene transfer was evaluated by using reverse transcription polymerase chain reactions (RT-PCR) to detect the presence of the transferred gene in the tenocytes. Enhancement of the expression of the target gene was assessed by RT-PCR with primers effective to amplify both internal and transferred genes. Expression of the type I collagen gene was determined by quantitative analysis of the products of RT-PCR.

RESULTS

Levels of expression of the type I collagen gene by tenocytes were increased significantly by transfer of the exogenous PDGF gene to the tenocytes. Efficiency of the gene transfer was confirmed by the presence of exogenous PDGF cDNA in the tenocytes receiving the transferred gene. Expression of the PDGF gene increased significantly in the cells treated with exogenous PDGF cDNA.

CONCLUSIONS

Exogenous PDGF genes can be transferred effectively into intrasynovial tenocytes and the transfer increases significantly the expression of genes for PDGF and type I collagen. Transfer of the PDGF gene may offer a novel way of effectively promoting healing of intrasynovial flexor tendons. The findings warrant future in vivo study to test the effectiveness of gene therapy to promote flexor tendon healing.

Vascular endothelial growth factor 121 and 165 in the subacromial bursa are involved in shoulder joint contracture in type II diabetics with rotator cuff disease

Vascular endothelial growth factor (VEGF) is a glycoprotein that plays an important role in neovascularization and increases vascular permeability. We reported that VEGF is involved in motion pain of patients with rotator cuff disease by causing synovial proliferation in the subacromial bursa (SAB). The present study investigates whether VEGF is also involved in the development of shoulder contracture in diabetics with rotator cuff disease. We examined 67 patients with rotator cuff disease, including 36 with complete cuff tears, 20 with incomplete tears, and 11 without apparent tears (subacromial bursitis). The patients were into groups according to the presence or absence of diabetes (14 type II diabetics and 53 non-diabetics). Specimens of the synovium of the SAB were obtained from all patients during surgery. Expression of the VEGF gene in the synovium of the subacromial bursa was evaluated by using the reverse transcriptase polymerase chain reaction. The VEGF protein was localized by immunohistochemistry, and the number of vessels was evaluated based on CD34 immunoreactivity. The results showed that VEGF mRNA was expressed in significantly more diabetics (100%, 14/14) than in non-diabetics (70%, 37/53) (P=0.0159, Fisher's test). Investigation of VEGF isoform expression revealed VEGF121 in all 14 diabetics and in 37 of the 53 non-diabetics, VEGF165 in 12 of the 14 diabetics and in 21 of the 53 non-diabetics, and VEGF189 in 1 of the 14 diabetics and in 2 of the 53 non-diabetics. No VEGF206 was expressed in either group. VEGF protein was localized in both vascular endothelial cells and synovial lining cells. The mean number of VEGF-positive vessels and the vessel area were also significantly greater in the diabetics (p<0.015, Mann-Whitney U test). Synovial proliferation and shoulder joint contracture were more common in the diabetics (P=0.0329 and P=0.073, respectively; Fisher's test). The mean preoperative range of shoulder motion significantly differed in terms of elevation between two groups: 103.8 degrees in diabetics and 124.9 degrees in no diabetics (p=0.0039 Mann-Whitney U test). In contrast, external rotation did not significantly differ: 44 degrees in diabetics and 49 degrees in non-diabetics (p=0.4957, Mann-Whitney U test). These results suggest that VEGF121 and VEGF165 expression in the SAB is responsible for the development of shoulder joint contracture, especially in elevation, among type II diabetic patients with rotator cuff disease.

Involvement of the subacromial bursa in impingement syndrome of the shoulder as judged by expression of tenascin-C and histopathology

Our aim was to evaluate bursal involvement at different stages of the impingement syndrome as judged by conventional histopathological examination and expression of tenascin-C, which is known to reflect active reparative processes in different tissues and disorders. Samples of subacromial bursa were taken from 33 patients with tendinitis, 11 with a partial tear and 18 with a complete tear of the rotator cuff, and from 24 control shoulders. We assessed the expression of tenascin-C, the thickness of the bursa, and the occurrence and degree of fibrosis, vascularity, haemorrhage and inflammatory cells. The expression of tenascin-C was significantly more pronounced in the complete tear group (p < 0.001) than in the partial tear, tendinitis or control groups. It was more pronounced in the tendinitis group than in the control group (p = 0.06), and there was more fibrosis in all the study groups than in the control group. The changes in the other parameters were not equally distinctive. Expression of tenascin-C did not correlate with the conventional histopathological parameters, suggesting that these markers reflect different phases of the bursal reaction. Tenascin-C seems to be a general indicator of bursal reaction, being especially pronounced at the more advanced stages of impingement and this reaction seems to be an essential part of the pathology of impingement at all its stages.

Tissue absorption and distribution of ketoprofen after patch application in subjects undergoing knee arthroscopy or endoscopic carpal ligament release

The diffusion into the target tissues of ketoprofen (CAS 22071-15-4), a widely used nonsteroidal anti-inflammatory drug, from a new topical patch has been studied after repeated patch application in comparison with its plasma level. Ten patients (5 women and 5 men) with a mean age of 45.0 +/- 12.3 years (mean +/- SD), scheduled for arthroscopic meniscectomy (5 subjects) or endoscopic carpal tunnel decompression (5 subjects), were asked to apply one patch with 100 mg ketoprofen on the affected body site once a day during the 6 days before the scheduled surgery. The last patch was kept for 6 h, and removed just a few minutes before surgery, when venous blood was drawn. Biopsies of the synovial tissue of the medial compartment and of the anterior fat pad (Hoffa's tissue) or of the ulnar bursa were taken during knee arthroscopy or endoscopic carpal tunnel release, respectively. An average plasma value of 52.8 +/- 30.1 (SD) ng/ml of ketoprofen was obtained in the 10 patients. The tissue concentrations of ketoprofen in the 5 subjects undergoing knee arthroscopy were 27.9 +/- 26.1 ng/g (range 7.2-67.1 ng/g) in the anterior fat pad and 239.0 +/- 163.0 ng/g (range 20.0-430.5 ng/g) in the synovial tissue. Drug concentrations up to 1000 times higher were found in the tendon sheath tissue of the ulnar bursa of the five patients undergoing endoscopic carpal tunnel release: average values of 20,107 +/- 7359 ng/g (range 13,004-32,578 ng/g) were obtained in this tissue. Data observed in this trial are consistent with those previously published by other authors, and demonstrate that ketoprofen applied on the skin is able to enter the subcutaneous and intra-articular tissues, reaching concentrations markedly higher than in plasma, and is further able to produce the desired pharmacological activity in situ, whereas plasma concentrations are too low to produce any systemic activity or side effect.

Interleukin-1-induced subacromial synovitis and shoulder pain in rotator cuff diseases

OBJECTIVE

To determine the relationship between the expression of interleukin-1beta (IL-1beta) and IL-1 receptor antagonists (IL-1ra) in the subacromial bursa and shoulder pain in rotator cuff diseases.

METHODS

Synovial specimens were analysed using various methods including reverse transcriptase-polymerase chain reaction (RT-PCR), immunohistochemistry and in situ RT-PCR. Thirty-nine patients with rotator cuff diseases were candidates. The degree of their shoulder pain was evaluated using a visual analogue scale.

RESULTS

The mRNA expression levels of the cytokines were significantly correlated with the degree of pain [IL-1beta: r=0.782; secreted IL-1ra (sIL-1ra): r=0.756; intracellular IL-1ra (icIL-1ra): r=0.806, P<0.001, respectively]. The combined results of immunohistochemistry and in situ RT-PCR analysis indicated that both synovial lining and sublining cells produce IL-1beta, while synovial lining cells predominantly produce icIL-1ra and sublining cells secrete sIL-1ra.

CONCLUSIONS

The differential regulation of the two forms of IL-1ra mRNAs may play an important role in shoulder pain in rotator cuff diseases, regulating IL-1-induced subacromial synovitis.

Vascular endothelial growth factor (VEGF) expression in the subacromial bursa is increased in patients with impingement syndrome

Vascular endothelial growth factor (VEGF), which is known to be an angiogenetic factor, plays an important role in the inflammation of synovial tissue. To investigate the relationships between VEGF and clinical symptoms in rotator cuff disease, VEGF expression was examined using RT-PCR and immunohistochemical analysis in 50 patients with this disease (26 with full-thickness cuff tear, 12 with partial-thickness tear, and 12 with subacromial bursitis). VEGF mRNA expression was detected in 40 out of 50 patients by RT-PCR. VEGF mRNA expression was found more frequently in the patients with motion pain (39 out of 41) than in those without motion pain (1 out of 9) with statistical significance (Fisher's test, P < 0.001). Thirty-one out of 33 patients with synovial proliferation showed VEGF mRNA expression, whereas the expression of this transcript was found in 9 out of 17 patients without synovial proliferation. This association with synovial proliferation was also significant (Fisher's test, P = 0.0013). Thirty out of 41 patients with motion pain had synovial proliferation but 3 out of 9 patients without motion pain had synovial proliferation. In all these 30 patients with both motion pain and synovial proliferation, VEGF mRNA expression was detected. This association between motion pain and synovial proliferation was also significant (Fisher's test, P < 0.05). The mean vessel count and area in subacromial bursa expressing VEGF was significantly higher than in those without VEGF (Mann Whitney's U test, P < 0.01). These results suggested that VEGF expression is associated with vascularity, synovial proliferation and shoulder motion pain in the rotator cuff disease.

Expression of procollagen alpha 1 type III mRNA in rotator cuff tears

The purpose of this study was to investigate the relationship among expression of procollagen alpha 1 type III mRNA, subacromial adhesion, and limited shoulder elevation in rotator cuff tears. Procollagen alpha 1 type III mRNA was analyzed in the torn supraspinatus tendons and synovial tissue of 42 patients with rotator cuff tears. As a control, four normal supraspinatus tendons of patients who had undergone shoulder surgery other than rotator cuff repair served as controls. Cells stained positively for procollagen alpha 1 type III mRNA were more abundant in the adhesive synovium of the subacromial bursa and in the torn supraspinatus tendons than in controls. Patients with complete-thickness tears who had undergone surgery less than 10 months after trauma were found to have more signal-positive cells than those later than 10 months. We conclude that the adhesive synovium of the subacromial bursa contains abundant cells stained positively for procollagen alpha 1 type III mRNA. We suggest that the production of type III collagen by these cells could contribute to the limitation of shoulder motion in patients with rotator cuff tears, and recommend release and excision of the excess adhesive synovium during rotator cuff surgery.

Rheumatoid arthritis and p53: how oxidative stress might alter the course of inflammatory diseases

Oxidative stress at sites of chronic inflammation can cause permanent genetic changes. The development of mutations in the p53 tumor suppressor gene and other key regulatory genes could help convert inflammation into chronic disease in rheumatoid arthritis and other inflammatory disorders.

Increased interleukin-1beta production in the synovium of glenohumeral joints with anterior instability

Macroscopic synovitis of the glenohumeral joint is frequently seen during arthroscopy in patients with anterior instability. Interleukin-1beta is known to be expressed in inflamed tissue, to correlate with the magnitude of inflammation, and to affect articular cartilage in the joint. We hypothesized that chronic synovitis may occur in the glenohumeral joint in patients with anterior instability. The purpose of this study was to examine the expression of interleukin-1beta in the synovium of the glenohumeral joint with anterior instability and to discuss its clinicopathologic significance. Specimens of synovial tissue around the greater tuberosity in the subacromial synovium (as controls) and around the rotator interval in the glenohumeral synovium were obtained from 10 patients who had anterior instability without signs of subacromial impingement. Semiquantitative reverse transcriptase-polymerase chain reaction was used to compare the levels of interleukin-1beta mRNA expression in the glenohumeral joint with those in the subacromial bursa. We also employed immunohistochemistry and in situ reverse transcriptase-polymerase chain reaction to detect the cells producing interleukin-1beta protein and mRNA. The levels of interleukin-1beta mRNA expression were significantly higher in the glenohumeral joint than in the subacromial bursa (p < 0.01). Histology showed nonspecific inflammation in all 10 samples of glenohumeral synovium, whereas no inflammation was seen in seven of 10 samples of subacromial synovium. Immunohistochemistry identified interleukin-1beta protein in the vessels and inflammatory and synovial cells (from lining to sublining layers) in synovium of the glenohumeral joint, whereas immunoreactivity was negative in seven subacromial bursa. The remaining three synovial specimens of subacromial bursa, however, showed positive immunoreactivity that was unremarkable and confined around the vessels. In situ reverse transcriptase-polymerase chain reaction was exclusively performed in the synovial specimens of the glenohumeral joint, which exhibited a positive reaction (in the same kinds of cells as seen with immunohistochemistry) in the lining and sublining layers and to a lesser extent in the stroma. Thus, our data confirmed the increased production of interleukin-1beta in the synovium of the glenohumeral joint in patients with anterior instability, suggesting the presence of chronic inflammation at the site. We conclude that this chronic synovitis may be partly associated with the development of dislocation arthropathy in the long term.

Increased substance P in subacromial bursa and shoulder pain in rotator cuff diseases

The subacromial bursa is recognized as a site associated with the shoulder pain caused by rotator cuff disease in the middle-aged and elderly. Substance P is contained in primary afferent nerves, and its quantity increases during chronic pain. The amount of substance P in the subacromial bursa of patients with rotator cuff disease was examined. Radioimmunoassay and immunohistochemistry were employed to quantify and localize substance P. The preoperative pain level was measured with a visual analogue scale with 0 as no pain, 5 as moderate, and 10 as severe. Thirty-seven patients that had undergone operation were divided into two groups: one composed of 19 patients with subacromial bursitis and a partial-thickness tear of the rotator cuff (nonperforated cuff) and the other composed of 18 patients with a full-thickness tear (perforated cuff). Subacromial bursae obtained from seven fresh cadavers with no shoulder pain before death were used as controls. The visual analogue scale showed significantly greater pain in the group with the nonperforated rotator cuff than in the group with the perforated cuff. Consistent with these results, the amount of substance P in the subacromial bursa was significantly greater in the former group than in the latter. Nerve fibers immunoreactive to substance P were localized around the vessels, with a larger number of fibers in the group with the nonperforated rotator cuff. Therefore, an increased amount of substance P in the subacromial bursa appears to correlate with the pain caused by rotator cuff disease.

Sensory nerve supply in the human subacromial bursa

The subacromial bursa is the major component of the subacromial gliding mechanism. The neural elements of the subacromial bursa obtained from specimens that underwent autopsy and surgery were investigated by the silver impregnation and immunohistochemical methods with antisera to substance P and calcitonin gene-related peptide; which are considered to be involved in nociceptive transmission, and protein gene product 9.5. Free nerve endings, Ruffini endings, Pacinian corpuscles, and two kinds of unclassified nerve endings were observed. Most of these receptors were observed of the roof side of the coracoacromial arch, which is exposed to stress because of the impingement. A delta and C fibers, thought to be nerve fibers of free nerve endings, were immunoreactive to substance P and calcitonin gene-related peptide. On the other hand, thick fibers thought to originate in encapsulated mechanoreceptors were not immunoreactive to substance P. The subacromial bursa receives nociceptive stimuli and proprioception and seems to regulate appropriate shoulder movement.

Tissue and epithelial cell-specific expression of chicken proto-oncogene c-ros in several organs suggests that it may play roles in their development and mature functions

Proto-oncogene c-ros codes for a receptor-type protein tyrosine kinase (PTK) sharing high homology with the Drosophila sevenless protein. Recent studies of c-ros expression in mouse by in situ hybridization showed that c-ros was expressed specifically and transiently in the epithelial cells of late embryonic kidney collecting duct and intestine villi. Those investigators suggested that c-ros may play a role in the development of those organelles. In the present study, we have examined the expression profile of c-ros in chicken by RNAase protection and in situ hybridization with riboprobes. Our results showed that in addition to kidney and intestine, low levels of c-ros mRNA could also be detected in lung, testis, thymus and bursa. Expression of c-ros commences during middle to late embryonic stages in those organs and persists into the adult life. In situ hybridization revealed that expression of c-ros was restricted to the epithelial cells of all the tissues examined including kidney, intestine, bursa, thymus and testis. In kidney c-ros was detected in all the epithelial cells of the collecting ducts, in intestine it was detected in the epithelial cells of villi and the underneath crypts. Our finding of c-ros expression in chicken differs from those in mouse in (1) instead of transient expression during the embryonic stage, expression of c-ros in chicken kidney and intestine persists into the adult life and (2) expression of c-ros in renal collecting ducts is not restricted to its growing tips, instead it is expressed in the entire epithelial layer of the ducts. Our results suggest that c-ros may play a role not only in the initial induction events in the organogenesis, but also in the mature function of those organs.

Amyloid deposits in surgically removed articular and periarticular tissue

In tissue from 13 of 30 patients subjected to meniscectomy, amyloid degeneration was found to varying extent along the surface of the meniscus. Tissue from 30 synovectomies, 30 bursectomies and 30 ganglia showed amyloid deposits in four, six and eight cases, respectively. Amyloid was found significantly more frequently in older patients, but there was no sex difference and no relation to duration of the symptoms or to other histological changes in the tissue. Micro-deposits of amyloid in joint tissue and tissue neighbouring joints are a frequent finding, especially in elderly persons, but the clinical significance of this finding is not clear.