Julian D. McNeil

The Oxidative Inactivation of Tissue Inhibitor of Metalloproteinase-1 (TIMP-1) by Hypochlorous Acid (HOCl) is Suppressed by Anti-Rheumatic Drugs

Tissue inhibitors of metalloproteinases (TIMPs) prevent uncontrolled connective tissue destruction by limiting the activity of matrix metalloproteinases (MMPs). That TIMPs should be susceptible to oxidative inactivation is suggested by their complex tertiary structure which is dependent upon 6 disulphide bonds. We examined the oxidative inactivation of human recombinant TIMP-1 (hr TIMP-1) by HOCl and the inhibition of this process by anti-rheumatic agents. TIMP-1 was exposed to HOCl in the presence of a variety of disease modifying anti-rheumatic drugs. TIMP-1 activity was measured by its ability to inhibit BC1 collagenase activity as measured by a fluorimetric assay using the synthetic peptide substrate (DNP-Pro-Leu-Ala-Leu-Trp-Ala-Arg), best cleaved by MMP-1. The neutrophil derived oxidant HOCl, but not the derived oxidant N-chlorotaurine, can inactivate TIMP-1 at concentrations achieved at sites of inflammation. Anti-rheumatic drugs have the ability to protect hrTIMP-1 from inactivation by HOCl. For D-penicillamine, this effect occurs at plasma levels achieved with patients taking the drug but for other anti-rheumatic drugs tested this occurs at relatively high concentrations that are unlikely to be achieved in vivo, except possibly in a microenvironment. These results are in keeping with the concept that biologically derived oxidants can potentiate tissue damage by inactivating key but susceptible protein inhibitors such as TIMP-1 which form the major local defence against MMP induced tissue breakdown.

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.

Abnormalities of gastric and esophageal emptying in polymyositis and dermatomyositis

Gastric and esophageal emptying were assessed using scintigraphic techniques in 13 patients with polymyositis or dermatomyositis and in 13 normal volunteers. Esophageal emptying was significantly delayed in patients, with 8 of 13 patients being outside the normal range. Gastric emptying was also markedly slower in patients than in controls, with 8 patients being outside the normal range for solid emptying and 8 patients beyond the normal range for liquid emptying. The 5 patients with dysphagia all had delayed esophageal emptying, but both gastric and esophageal emptying were delayed in some asymptomatic patients. There was a significant correlation between esophageal emptying and both solid and liquid gastric emptying in the patients. Both gastric and esophageal emptying correlated with the severity of the peripheral (skeletal) muscle weakness. These results indicate that profoundly delayed gastric and esophageal emptying are common in polymyositis and dermatomyositis, implying frequent malfunction of the smooth muscle of the upper gastrointestinal tract in this disease.

Regulation of Insulin-Like Growth Factor-Binding Protein-5 by Insulin-Like Growth Factor I and Interleukin-1α in Ovine Articular Chondrocytes1

Insulin-like growth factors (IGFs) contribute to the maintenance of the cartilage matrix by stimulating proteoglycan synthesis. In contrast, interleukin-1 (IL-1), an inflammatory cytokine, suppresses the synthesis of proteoglycans. In pathological conditions the chondrocytes’ responsiveness to IGF-I is decreased, and elevated levels of IGF-binding proteins (IGFBPs) have been implicated as a possible cause. The aim of this study was to investigate the effects of IGF-I and IL-1 on IGFBP production by ovine articular chondrocytes (OAC) and the roles of these IGFBPs in the regulation of proteoglycan synthesis. As revealed by Western ligand and immunoblotting, OACs secreted IGFBP-2 and a 24-kDa IGFBP in culture medium under basal conditions. Exposure of the cells to IGF-I for 48 h resulted in the appearance of IGFBP-5 in the medium. Des(1–3)IGF-I, an IGF-I analog with reduced affinity for IGFBPs, also increased the level of IGFBP-5, but to a lesser extent than IGF-I, whereas LR3IGF-I, which has virtually no af...

Hand syndromes associated with diabetes: impairments and obesity predict disability.

Objective. We determined patterns of disability in diabetic hand conditions and identified factors that contributed to functional limitations. Methods. Hand assessments were performed on 60 adults with DM1 or DM2 and carpal tunnel syndrome, trigger finger, Dupuytren’s disease, or the syndrome of limited joint mobility. The examination included measurement of grip strength, light touch perception, and dexterity, as well as self-reported function using the Disabilities of the Arm, Shoulder and Hand (DASH) instrument and the Medical Outcomes Study Short Form-36 questionnaire. Associations with hand disability were analyzed using correlation and regression. Results. The most frequent presentation was carpal tunnel syndrome (45%) but it was common for patients to present with clinical features associated with more than one hand syndrome (47%). Overall, women had greater difficulties, with significantly higher DASH scores than men [mean 30.3 (95% CI 23.2, 37.5) vs 18.0 (95% CI 12.1, 23.9), respectively; p = 0.01]. Grip strength, dexterity, and obesity were associated with hand disability (p < 0.05). Conclusion. In adults with hand syndromes associated with diabetes, disability was related to impaired muscle function and carpal tunnel syndrome. Obesity and overall physical functioning influenced hand disability, particularly in women.

Osteoporosis education improves osteoporosis knowledge and dietary calcium: comparison of a 4 week and a one-session education course

Background:  Education is ideal for osteoporosis because many risk factors are modifiable. However, the efficacy of shortened education courses compared to a standard 4 week course for improving osteoporosis knowledge and healthy behaviours is not known. This study aimed to assess whether education changed knowledge and healthy behaviours over 3 months of follow‐up; and whether changes in these outcomes were different between participants receiving the different education courses.

Insulin-like growth factor binding proteins (IGF-BPs) in bovine articular and ovine growth-plate chondrocyte cultures: their regulation by IGFs and modulation of proteoglycan synthesis

Cultured chondrocytes respond to insulin-like growth factors (IGFs) by increasing the production of proteoglycans and insulin-like growth factor binding proteins (IGF-BPs). To investigate the biological effects of IGFs and IGF-BPs, isolated bovine articular and ovine growth-plate chondrocytes were cultured at high density in the presence of IGF-1, and its truncated form, des (1-3) IGF-I. Both growth factors stimulated the production of IGF-BPs in articular and growth-plate chondrocyte monolayers. Western ligand blots showed that bovine articular chondrocytes released two forms of IGF-BPs into conditioned medium with molecular weights of 29 and 31 kDa. Ovine growth-plate chondrocytes released four different forms of IGF-BPs of approx. 22, 24; 29-30 and 34 kDa. IGF-I and des (1-3) IGF-I stimulated total proteoglycan synthesis by articular chondrocytes up to 1.5-fold. The truncated analogue was more potent at lower concentrations, particularly in stimulating incorporation of newly synthesized proteoglycans into the cell-layer. The maximal stimulation of proteoglycan synthesis in ovine growth-plate chondrocyte culture was 3-fold with des (1-3) IGF-I, while IGF-I enhanced proteoglycan production by only 2-fold over the concentrations used. Our results suggest that endogenous IGF-BPs in chondrocyte cultures act as a part of a feed-back mechanism which diminishes the bioactivity of IGF-I.

Predictors of shoulder pain and shoulder disability after one year in diabetic outpatients

OBJECTIVE To investigate factors associated with changes in shoulder pain and disability in diabetic outpatients over 1 yr. METHODS Cross-sectional study with 12-month follow-up in diabetic outpatients (n = 179) using the shoulder pain and disability index (SPADI) and SF-36 version 2. RESULTS Patients with diabetes and shoulder pain or disability are more likely to be older and female. After 12 months of follow-up, one-quarter of participants without pre-existing symptoms at baseline developed clinically significant pain (28%) or disability (25%). Of the patients with pre-existing shoulder pain or disability, half reported clinically significant worsening (10 percentage points) in shoulder pain (58%) or disability (45%) over 12 months. Few patients demonstrated clinically significant improvement in pain (11%) or disability scores (19%). The remaining one-third of the patients reported no change in symptoms (30% pain; 35% disability). Increasing intensity of pain scores between baseline and 12 months was associated with older age, higher HbA(1c) and less pain at baseline. Increasing disability score between baseline and 12 months was associated with having had eye laser surgery, greater pain at baseline and less disability at baseline. CONCLUSION Shoulder pain and disability are common, and persistent in adults with diabetes. Having higher HbA(1c) levels or having had treatment for retinopathy was associated with worsening shoulder pain and disability, confirming that glycaemic control and diabetic complications are associated with worsening shoulder pain or disability over 12 months of observation.

Deteriorating tactile sensation in patients with hand syndromes associated with diabetes: a two-year observational study

AIMS To observe the natural history of hand function during a two-year period in participants with hand syndromes associated with diabetes and to determine factors related to changing function. METHODS Hand function was measured over three annual visits using Disability of the Arm, Shoulder and Hand (DASH) and SF-36v2 questionnaires, grip strength, light touch and 9-hole peg tests. Light touch was tested with WEST monofilaments at 7 sites on the hand (score 35 to 0). Data were analyzed using repeated-measures ANOVA, Spearmans correlation, and Wilcoxon signed-rank tests. RESULTS Participants (n=60) were aged 61 ± 10.5 years, 57% female, diagnosed with diabetes and at least one of four associated hand disorders. Presentations of carpal tunnel syndrome, or past release (n=27, 45%) and trigger finger (n=24, 40%) were common. Tactile sensation was reduced during the two-year period (median, range; 30 months, 25-40 months). Initial median (inter-quartile range) scores for the dominant hand of 25.5 (22-28.5) were reduced to 23 (21.5-27). This sensory loss was weakly associated with HbA1c (r=0.30, p=0.05) and occurred predominantly in participants with trigger finger (p=0.05). CONCLUSIONS Light touch perception was reduced in longstanding diabetic hand syndromes. Tactile abnormalities that were detected by clinical examination progressed during a two year period and were related to metabolic control and musculoskeletal diagnosis.

Insulin-like growth factor binding protein-5 proteolytic activity in ovine articular chondrocyte culture

We have previously demonstrated that ovine articular chondrocytes synthesise and release insulin-like growth factor binding protein-5 (IGFBP-5) which subsequently undergoes proteolysis in the tissue culture medium. The IGFBP-5 proteolytic activity has now been characterised and its substrate specificity analysed using recombinant IGFBP-5 and purified chondrocyte-derived IGFBPs. Iodinated human recombinant IGFBP-5 was incubated with chondrocyte culture or conditioned medium in the presence or absence of various inhibitors. Serine protease inhibitors aprotinin and heparin effectively inhibited the breakdown of IGFBP-5. Furthermore, insulin-like growth factor-I (IGF-I) but not its structural analogues with reduced affinity for IGFBP-5, was also able to partially protect IGFBP-5 from degradation indicating that the association of IGF with the binding protein was required for the inhibition of the proteolytic activity. The inflammatory cytokine interleukin-1 did not have any effect on IGFBP-5 proteolysis. The proteolytic activity appears to be IGFBP-5-specific since the incubation of chondrocyte-derived IGFBPs with chondrocyte conditioned medium resulted in the loss of IGFBP-5 while the levels of the other two IGFBPs (IGFBP-2 and a 24 kDa IGFBP) remained unchanged. In conclusion, we show that IGFBP-5 is specifically cleaved by a serine protease released by primary cultures of ovine articular chondrocytes and also demonstrate the ability of IGF-I to inhibit the proteolytic activity both in cell culture and in cell-free conditions.