Phagocytic synovial lining cells regulate acute and chronic joint inflammation after antigenic exacerbation of smouldering experimental murine arthritis

Vascular permeability factor/vascular endothelial cell growth factor (VPF/VEGF) can both potently enhance vascular permeability and induce proliferation of vascular endothelial cells. We report here that mouse or human mast cells can produce and secrete VPF/VEGF. Mouse mast cells release VPF/VEGF upon stimulation through Fcepsilon receptor I (FcepsilonRI) or c-kit, or after challenge with the protein kinase C activator, phorbol myristate acetate, or the calcium ionophore, A23187; such mast cells can rapidly release VPF/VEGF, apparently from a preformed pool, and can then sustain release by secreting newly synthesized protein. Notably, the Fc epsilonRI-dependent secretion of VPF/VEGF by either mouse or human mast cells can be significantly increased in cells which have undergone upregulation of Fc epsilonRI surface expression by a 4-d preincubation with immunoglobulin E. These findings establish that at least one cell type, the mast cell, can be stimulated to secrete VPF/VEGF upon immunologically specific activation via a member of the multichain immune recognition receptor family. Our observations also identify a new mechanism by which mast cells can contribute to enhanced vascular permeability and/or angiogenesis, in both allergic diseases and other settings.     

Hemangioma of the synovial membrane of the knee joint

The data on 15 patients with hemangioma of the synovial sheath of the knee joint are reported. It is the author's opinion that surgical removal of the tumor is the most radical method of treatment for hemangiomas. Among 15 patients such procedure was accomplished in 6, in the remainder biopsy or partial removal of the tumor followed by radiotherapy were performed. Late results were followed up in 9 patients.     

Glutathione depletion in epithelial lining fluid of lung allograft patients

The lower respiratory tract is protected against reactive oxygen species (ROS) by a complex antioxidant system. In the epithelial lining fluid (ELF), glutathione (L-alpha-glutamyl-L-cysteinylglycine, GSH) is essential for adequate protection of pneumocytes from potential toxicity mediated by extracellular hydrogen peroxide (H2O2). We assessed the concentration of total GSH in bronchoalveolar lavage fluid (BALF) in lung allograft patients in the absence and presence of acute rejection. Bronchoalveolar lavage (BAL) and biopsies were performed concurrently on 36 occasions in 17 patients who had undergone lung transplantation. BALF samples were divided into two groups on the basis of presence or absence of acute lung rejection on transbronchial biopsy. Seven BALF samples were obtained from control subjects for comparison. The BALF data demonstrated significantly lymphocyte recruitment and evidence of lung injury during acute rejection episodes. Transplant allografts without rejection showed significant depletion of total GSH in the ELF as compared with that of normal volunteers (94.0 +/- 9.7 microM versus 302.6 +/- 40.8 microM, p < 0.01). Transplant allografts with acute rejection had a slightly higher GSH concentration in their ELF (179.8 +/- 34.7), but this was still lower than control values. The deficiency of total GSH in the alveolar fluid may predispose lung allografts to extracellular H2O2-mediated toxicity.     

Menisci and synovial folds of the metacarpophalangeal joint of the thumb

The inner surface of 25 thumb metacarpophalangeal joints were investigated and the arrangement and structure of different folds protruding into the joint cavity at the level of the joint cleft studied. At the ulnar and radial sides, compact wedgeshaped folds are found consisting of collagenous fibres, which connect with the fibrous layer of the joint capsule. The circularly arranged fibrous tissue is covered by a thin layer of cartilaginous cells. From a structural and functional point of view they are comparable to the menisci of the knee joint. In contrast, a different kind of tissue is found at the palmar and dorsal circumference of the joint cleft: typical synovial folds, consisting of loose connective tissue and small fat lobules. These are suggested not to fulfill a particular mechanical function but to act as a malleable spacer which is able to conform to the requirements of joint mobility.     

Measurement of synovial lining volume by magnetic resonance imaging of the knee in chronic synovitis

OBJECTIVES: Current methods of monitoring chronic synovitis in a single joint rely on clinical examination derived indices, such as the detection of synovial thickening. This study aimed to develop a reproducible method for quantifying the volume of synovial lining in chronic synovitis using contrast enhanced magnetic resonance (MR) imaging. METHODS: The knees of 18 patients with chronic synovitis were examined (34 studies). A 2D T1 weighted FLASH sequence was used to evaluate the temporal enhancement of synovial structures after intravenous contrast. Synovial lining volume was calculated from subtraction of pre and post-enhancement 3D T1 weighted MP RAGE images with thresholding and pixel counting. Eleven patients were examined before and after intra-articular glucocorticoid (mean interval 14 weeks) and MR data compared with changes in clinical examination derived indices of disease activity. RESULTS: Synovial lining volume varied from 52-267 ml. The coefficient of variation in volume calculation was 3.5% for a single observer and was 3.8% for two observers. Synovial lining volume was quantified in all patients where synovial lining thickening could not be detected clinically. A decrease in synovial lining volume of > 40% was associated with an improvement in synovial lining thickening, detected clinically. Decreases in synovial lining volume were quantified by MR in two of three patients where changes in clinical examination derived indices were inconsistent. CONCLUSIONS: A reproducible method of estimating the volume of synovial lining in patients with chronic synovitis has been developed. MR measurement of synovial lining volume may quantify changes in chronic synovitis that remain unidentified by clinical measures.     

Experimental osteoarthritis in the rabbit knee joint

The development of arthrotic-like changes following the resection of the cruciate ligaments in the knee joint of rabbits has been studied at intervals from 2 weeks to 10 months in 35 animals. Signs of cartilage degeneration were followed by changes in the subchondral bone, where formation of osteophytes and condensation took place. An increased vascular supply was demonstrated by microangiographic and scintigraphic investigations. The uptake of 18F and 99mTc-polyphosphate reached a maximal value about 2 months after the operation and then diminished despite further development of arthrotic changes.     

Snapping elbow caused by the synovial fold in the radiohumeral joint

We report herein the case of a patient with chronic renal failure in whom mitral valve stenosis with extensive mitral anular calcification involving the entire anulus and leaflets was successfully treated surgically. Excision of both leaflets and partial resection of the anular calcification enabled the insertion of a 23-mm St. Jude Medical prosthetic valve. The technical difficulties involved with inserting the appropriate-sized prosthetic valve in a narrowed mitral anulus with heavy calcification are discussed following this case report.     

Phorbol ester modulation of rabbit corneal endothelial permeability

PURPOSE: Phorbol esters have been shown to have a profound influence on cellular activity in many cell types. The purpose of this study was to examine the influence of phorbol esters on the function and structure of corneal endothelial cells. METHODS: Corneas were placed under a specular microscope, and the endothelium was superfused with glutathione bicarbonate Ringer's solution (GBR); with GBR and 10 nM, 100 nM, or 1 microM 4 beta-phorbol 12-myristate 13-acetate (PMA); or with 100 nM 4-alpha-PMA. Corneal swelling curves were generated, and endothelial permeability was determined. Corneal endothelial structure was examined with a scanning electron microscope. RESULTS: Significant increases in swelling and endothelial permeability were found in corneas perfused with 100 nM PMA versus that observed in controls (swelling rate = 26 microns/hr versus 6.9 microns/hr; permeability = 6 x 10(-4) cm/min versus 3.4 x 10(-4) cm/min) and in corneas receiving 1 microM PMA versus that in controls (swelling rate = 26.3 microns/hr versus 0.12 micron/hr; permeability = 6.9 x 10(-4) cm/min versus 4.9 x 10(-4) cm/min). Application of 10 nM PMA did not significantly alter either parameter. Study with transmission electron microscope demonstrated significant morphologic changes in cells perfused with all concentrations of PMA. Corneas perfused with 100 nM 4-alpha-PMA versus 100 nM PMA had significantly lower slope and permeability values (swelling rate = 5.9 microns/hr versus 25.1 microns/hr; permeability = 3 x 10(-4) cm/min versus 6.7 x 10(-4) cm/min). CONCLUSIONS: Phorbol esters are detrimental for corneal endothelial function, creating significant corneal swelling, increases in endothelial permeability, and changes in endothelial cell structure. This effect appears to be mediated through a protein kinase C pathway.     

Dibutyryl cGMP raises cytosolic concentrations of Ca2+ in cultured nodose ganglion neurons of the rabbit

Airway hyperresponsiveness in asthma has been attributed to impaired ability of deep inspiration (DI) to stretch airway smooth muscle. We have retested this hypothesis by comparing the responses to methacholine of 10 asthmatic and 10 control subjects. After each dose subjects breathed tidally without deep inspiration for 4 min, followed by a forced partial expiration from which flow was measured at a constant volume, 35% baseline VC (Vp 35). This index is independent of both DI and increases in end-inspiratory lung volume (EILV). EILV increased significantly more in the asthmatic group than in the control group (15.0 versus 2.5% of baseline VC, p = 0. 019), a factor that if not taken into account would tend to mask the difference in the two responses. Comparisons were made after a cumulative dose of 50 microg methacholine, which was the highest dose common to all subjects. The asthmatic response was significantly greater than that seen in the control group, with reductions to 25.9 and 72.1% of baseline Vp 35, respectively (p = 0. 0007). We conclude that the sensitivity of asthmatic airways to methacholine is greater than that of normal airways even when DI is prohibited. Therefore, the hyperresponsiveness of asthmatic airways is not attributable simply to an inability of DI to stretch airway smooth muscle.     

Reduction in water permeability of the rabbit conjunctival epithelium by hypotonicity

The effects of unilateral exposure to hypotonic media on the diffusional water permeability of the isolated rabbit conjunctiva were determined. For these experiments, a segment of the bulbar-palpebral conjunctiva was mounted between Ussing-type hemichambers under short-circuited conditions. Unidirectional diffusional water fluxes (Jdw) were measured in either direction by adding 3H2O to one hemichamber and sampling from the other. Electrical parameters were measured simultaneously. Jdw were determined in control isosmotic conditions and after dilution of one of the bathing solutions from 290 to 108 mOsMolar. This hypotonic condition reduced Jdw by 25-30% (n = 17) when applied basolaterally and by 25% (n = 6) apically. The effects were reversible and were also obtained when the opposite bathing solution contained amphotericin B, selectively permeabilizing the contralateral cell surface. From concomitant changes in transepithelial electrical resistance as well as 14C-mannitol fluxes completed under identical conditions, arguments are presented that the above effect is best explained as a cell regulated reduction in membrane water permeability. Presumably both apical and basolateral membranes can down-regulate their water permeabilities. This response, suggesting a protective mechanism to help maintain cell volume from hypotonicity, was also seen in other studies using the amphibian bladder and the frog cornea, in which the effect was only obtained basolaterally. Thus, regulation of epithelial water permeability appears to be a basic trait common to both amphibians and mammals, although tissue differences exist.     

Molecular lysis of synovial lining cells by in vivo herpes simplex virus-thymidine kinase gene transfer

Herpes simples virus thymidine kinase (HSV-TK) expression plasmid DNA was injected into the joint space of rabbits with antigen-induced arthritis (AIA). Purified plasmid DNA was able to mediate transfection of synovial lining cells and transient overexpression of HSV-TK in the context of active synovial inflammation. The pharmacodynamic distribution of intraarticular expression plasmid DNA was confined to the joint space. Arthritic rabbits treated with intraarticular expression plasmid DNA followed by intravenous ganciclovir (GCV, 5 mg/kg) twice daily for 3 days showed histologic evidence of synovial lining layer cytolysis when articular tissues were examined 21 days posttreatment. There was also a reduction in joint swelling in the TK-treated knees. No untoward clinical effects were observed in the rabbits and no evidence of cytolytic damage specific to the TK-GCV gene therapy was observed either in the articular cartilage or bone. The application of TK-GCV intraarticular gene therapy using purified expression plasmid DNA for the induction of synovial cytolysis may be applicable to the treatment of human inflammatory arthritis.     

Tumor necrosis factor in synovial fluids of temporomandibular joint dysfunction syndrome

With the MTT tetrazolium WEHI 164 clone 13 cell cytotoxicity assay, we measured TNF alpha (tumor necrosis factor) activity in synovial fluids of TMJDS (Temporomandibular joint dysfunction syndrome). We found no detected TNF alpha level from 5 patients with muscle dysfunction, raised TNF alpha levels from 5 of 11 patients with internal derangement and from 9 of 11 patients with organic destruction (osteoarthritis). The findings of biologically active TNF alpha in synovial fluids of TMJDS suggest that TNF alpha may play a role in the pathogenesis of TMJDS.     

Intestinal permeability to small- and large-molecular-weight substances in the newborn rabbit

BACKGROUND/PURPOSE: The authors have previously reported the occurrence of spontaneous bacterial translocation (BT) and its resolution with age in the newborn rabbit. They have also reported a close correlation between small bowel bacterial colonization (BC-SB) and BT at 1 week of age, suggesting that the presence of luminal bacteria and their production of endotoxins may increase the intestinal permeability. The aim of this study was to evaluate intestinal permeability to small and large molecules in the newborn rabbit and to correlate it with BT. MATERIALS AND METHODS: New Zealand White rabbits (n = 96) 1, 7, 14, 21, and over 120 days (adult) of age were given either C14-labeled ethylene diamine tetraacetic acid (EDTA) (MW 290) or C14-Dextran (MW 70,000) via an orogastric tube at 1 mCi per 100 g of body weight. Five hours later, blood, urine, liver, and intestine were collected, and scintillation counting was performed after solubilization. In a separate series of rabbits (n = 136), the incidence of BT, BC-SB, and small intestinal surface area (SA) were measured. RESULTS: Total permeability to Dextran decreased with age and was significantly reduced at 14 days of age. In contrast, total permeability to EDTA increased and was maximal in 7- to 14-day-old rabbits and began to decrease at 21 days of age. The incidence of BC-SB rapidly increased at 7 days of age and reached 100% at 14 days of age. The incidence of BT peaked at 7 days of life (30%) and then decreased with age. SA increased rapidly in the first 3 weeks and SA growth rate of 21-day-old rabbits was almost 1,400% compared with 1-day-old rabbits. CONCLUSIONS: This study has shown an age-related reduction of intestinal permeability to large (Dextran) and small (EDTA) molecular weight particles. However, intestinal permeability to EDTA had a different pattern than Dextran, suggesting that there may be different mechanisms of intestinal permeability to different size molecules. Intestinal permeability to EDTA closely correlated with bacterial colonization and bacterial translocation, suggesting that changes in the intestinal bacterial environment may affect the intestinal permeability, possibly by activating the immune system secondary to increases in endotoxins and bacteria.     

Immunocytochemical demonstration of the synovial membrane in experimentally induced arthritis of the rat temporomandibular joint

The present study is first to report an experimental model of adjuvant-induced arthritis in the rat temporomandibular joint (TMJ). Arthritis was induced by simultaneous intradermal administrations of Freund's complete adjuvant, one at the parietal scalp and the other at the base of the tail. In this model, we demonstrated responses of the synovial membrane by immunocytochemistry using antibodies to OX6 and ED1 which recognize Ia antigen in MHC class II antigen-expressing cells and the macrophage/monocyte lineage, respectively. Three weeks after administration, no remarkable signs of inflammation were macroscopically recognizable in the TMJ, but microscopically the synovial membrane in the TMJ revealed marked changes such as enhanced vascularization and hemostasis in the sublining layer and a thickening in the synovial lining cell layer. Intense OX6-immuno-reactivity was found in the synovial lining cells at lesions in the experimental group but not in the control group. Immunoelectron microscopy revealed that these OX6-immunopositive synovial lining cells developed dense cytoplasmic processes and numerous vacuoles and vesicles, resembling type A cells. Part of the type A cells also showed ED1-immunoreactivity. The expression of OX6 or ED1 immunoreactivity in the synovial lining cells might be involved in the initial immune responses in this arthritis model because the synovial membranes are exposed to the synovial fluids which have been believed to contain antigenic substances.     

Local removal of phagocytic synovial lining cells by clodronate-liposomes decreases cartilage destruction during collagen type II arthritis

OBJECTIVE: To investigate whether local removal of phagocytic synovial lining cells (SLCs) from the knee joint before onset of collagen type II arthritis has an effect on development of cartilage destruction. METHODS: Phagocytic SLCs were selectively depleted by a single injection of clodronate laden liposomes in the knee joint seven days before induction of collagen type II arthritis (CIA). Clodronate laden liposomes were given in one knee joint either alone or in combination with a short-term oral treatment of dexamethasone. Cartilage damage including proteoglycan depletion and chondrocyte death was measured in total knee joints sections stained with safranin-o or haematoxylin. RESULTS: Local removal of phagocytic SLCs, seven days before arthritis onset, prevented cell influx for the larger part. Chondrocyte death was significantly decreased in the SLC depleted arthritic joint both at an early (6 days) and late (12 days) time point after CIA induction. However, depletion of proteoglycans from femoral and patellar cartilage layers was not prevented. If the mild acute inflammation caused by a single clodronate laden liposome injection in the left knee joint, was blocked by a short-term (on consecutive days 9, 8, 7, 6, 5 before CIA onset) oral treatment with dexamethasone, cell influx, but also proteoglycan depletion was almost completely blocked. In the contralateral control right knee joint prominent cell influx and severe cartilage damage was observed, indicating that there was no effect of dexamethasone anymore at the onset of CIA. CONCLUSIONS: This study shows that removal of phagocytic lining cells before CIA induction, particularly in the presence of a short-term treatment with dexamethasone, decreases cartilage destruction.     

Membrane properties and esterase activity of synovial lining cells: further evidence for a mononuclear phagocyte subpopulation

Recent work in our laboratory with mouse radiation chimeras suggests that the macrophage type of synovial lining cell is derived from bone marrow. Further evidence for including this cell type in he mononuclear phagocyte system is now presented. Rosette formation with IgG coated sheep red cells, immunofluorescent staining for surface Ia antigens, and nonspecific esterase staining all show the presence in the synovial lining of a subpopulation of cells carrying these markers. The proportion of such cells in the lining is very variable, as is the proportion of 'type A' cells recognised with the electron microscope.     

Elevated nerve growth factor levels in the synovial fluid of patients with inflammatory joint disease

A novel pH shock extraction procedure was used to measure nerve growth factor (NGF) levels in both normal and inflamed synovial fluids using a sensitive and specific two-site enzyme linked immunosorbant assay. To date no data is available on NGF levels in normal synovial fluids. Synovial fluids were taken from 5 normal volunteers, 12 patients with rheumatoid arthritis and 10 patients with other inflammatory arthropathies. The mean +/- SEM NGF concentration in normal synovial fluids was 95 +/- 33.2 pg/ml (range 39.1-143.1 pg/ml), whereas the mean NGF concentration in the synovial fluids taken from patients with rheumatoid arthritis was 532.5 +/- 123.8 pg/ml (range 152-1686 pg/ml). The mean NGF concentration in patients with other inflammatory arthropathies was also raised (430.6 +/- 90 pg/ml; range 89-1071 pg/ml). The NGF concentrations were significantly higher in the synovial fluids from both inflamed groups (ANOVA p < 0.05) compared to normals. Raised levels of NGF in synovial fluid may contribute directly to joint inflammation via activation of inflammatory cells.     

Low density lipoprotein of synovial fluid in inflammatory joint disease is mildly oxidized

The histologic diagnosis of adult renal epithelial neoplasms with prominent eosinophilic cytoplasm (renal oncocytoma, chromophobe renal-cell carcinoma (RCC), eosinophilic variant of clear-cell RCC, eosinophilic variant of papillary RCC, and collecting duct carcinoma), could be problematic in some cases because of overlapping morphologic features. Precise diagnosis is essential, however, because it often connotes a distinct biologic behavior. Proliferative activity has not been specifically investigated in this spectrum of renal tumors, so we studied the MIB-1 proliferation index in 20 renal oncocytomas, 12 chromophobe RCCs, 9 eosinophilic variants of papillary RCCs, and 13 eosinophilic variants of clear-cell RCCs. Our purpose was to identify the biologic potential of these renal tumors on the basis of MIB-1 tumor proliferation index and to ascertain whether that index had diagnostic value. Overall, nuclear grade correlated with MIB-1 tumor proliferation index (P=.03). The mean proliferation index progressively increased from renal oncocytomas (0.3) to chromophobe RCCs (0.8) to eosinophilic variants of papillary RCCs (2.2) to eosinophilic variants of clear-cell RCCs (4.1) (P=.002). None of the renal oncocytomas or chromophobe RCCs had an index greater than 2, whereas 8 of 13 eosinophilic variants of clear-cell RCCs had an index greater than 2; in 5 of these, it was more than 3. Thus, in the differential diagnosis between renal oncocytoma/chromophobe RCC and eosinophilic variant of RCC, an MIB-1 index of greater than 3 with appropriate morphologic correlation would strongly support the diagnosis of the latter. We also concluded that the progressive increase in MIB-1 tumor proliferation index across the spectrum of granular renal-cell neoplasms parallels the emerging data in the current literature concerning the biologic potential of adult renal epithelial tumors and justifies histologic categorization of adult renal epithelial neoplasms.