Tranexamic acid toxicity in human periarticular tissues.

OBJECTIVES: Tranexamic acid (TXA) is an anti-fibrinolytic medication commonly used to reduce perioperative bleeding. Increasingly, topical administration as an intra-articular injection or perioperative wash is being administered during surgery. Adult soft tissues have a poor regenerative capacity and therefore damage to these tissues can be harmful to the patient. This study investigated the effects of TXA on human periarticular tissues and primary cell cultures using clinically relevant concentrations. METHODS: Tendon, synovium, and cartilage obtained from routine orthopaedic surgeries were used for ex vivo and in vitro studies using various concentrations of TXA. The in vitro effect of TXA on primary cultured tenocytes, fibroblast-like synoviocytes, and chondrocytes was investigated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) cell viability assays, fluorescent microscopy, and multi-protein apoptotic arrays for cell death. RESULTS: There was a significant (p < 0.01) increase in cell death within all tissue explants treated with 100 mg/ml TXA. MTT assays revealed a significant (p < 0.05) decrease in cell viability in all tissues following treatment with 50 mg/ml or 100 mg/ml of TXA within four hours. There was a significant (p < 0.05) increase in cell apoptosis after one hour of exposure to TXA (100 mg/ml) in all tissues. CONCLUSION: The current study demonstrates that TXA caused significant periarticular tissue toxicity ex vivo and in vitro at commonly used clinical concentrations.Cite this article: M. McLean, K. McCall, I. D. M. Smith, M. Blyth, S. M. Kitson, L. A. N. Crowe, W. J. Leach, B. P. Rooney, S. J. Spencer, M. Mullen, J. L. Campton, I. B. McInnes, M. Akbar, N. L. Millar. Tranexamic acid toxicity in human periarticular tissues. Bone Joint Res 2019;8:11-18. DOI: 10.1302/2046-3758.81.BJR-2018-0181.R1.

Measuring the biological effect of presurgical metformin treatment in endometrial cancer.

BACKGROUND: Preclinical studies in endometrial cancer (EC) show that metformin reduces cellular proliferation by PI3K-AKT-mTOR inhibition. We tested the hypothesis that short-term presurgical metformin reduces cellular proliferation in atypical endometrial hyperplasia (AEH) and endometrioid EC, and assessed the feasibility of using phosphorylated PI3K-AKT-mTOR proteins as tissue end points. METHODS: Women with AEH or EC received metformin 850 mg twice a day or no drug in the presurgical window between diagnosis and hysterectomy. Before and after the window, tissue samples were obtained; serum markers of insulin resistance (e.g. homeostasis model of assessment of insulin resistance index) were determined; and anthropometrics measured (e.g. BMI). Cell proliferation (Ki-67) and PI3K-AKT-mTOR phosphostatus were assessed by immunohistochemistry and scored blinded to treatment. RESULTS: Twenty-eight metformin-treated and 12 untreated patients, well matched for age and BMI, completed the study. Metformin treatment (median 20 days, range 7-34) was associated with a 17.2% reduction in tumour Ki-67 (95% CI -27.4, -7.0, P=0.002), in a dose-dependent manner. Tumour PI3K-AKT-mTOR protein phosphostatus varied but the effects were not significant after adjusting for changes in controls. CONCLUSIONS: Short-term metformin was associated with reduced Ki-67 expression in EC. Changes in tumour PI3K-AKT-mTOR protein phosphostatus were seen in both groups. Future studies should address the variability attributed to different sampling techniques including devascularisation of the uterus at hysterectomy.

Acquired haemophilia - A diagnosis not to be missed.

Acquired haemophilia is a rare , life threatening bleeding disorder characterised by the development of auto-antibodies to coagulation factor VIII. Diagnosis is based upon the clinical history of mucocutaneous haemorrhages combined with a selective prolongation of the APTT. The condition is associated with a wide range of conditions, such as autoimmune diseases , solid and haematological malignancies. Treatment involves controlling the bleeding manifestations and eliminating the inhibitor antibodies. Three cases from our recent practice are used to highlight the variable severity of this condition.

Interleukin-18 levels in induced sputum are reduced in asthmatic and normal smokers.

BACKGROUND: IL-18 is a cytokine which is known to have an important role in the development of a Th1 lymphocyte response. As such, it may have a regulatory role in asthma by modifying Th2 lymphocyte responses. Cigarette smoking may amplify the airway inflammation associated with asthma. OBJECTIVE: This study investigated if IL-18 could be detected in induced sputum from asthmatics and normal subjects and if smoking altered IL-18 levels. METHODS: Induced sputum was obtained from asthmatic (31 smokers, 35 non-smokers) and normal (20 smokers, 20 non-smokers) subjects. All smokers had a smoking history of > or =15 pack years. IL-18 levels in sputum supernatant were measured by ELISA. IL-18 mRNA expression and cellular localization were assessed by quantitative PCR and immunocytochemistry, respectively. RESULTS: Smoking was associated with a significant reduction in IL-18 levels (median (interquartile range) - smokers 20 (0-102) pg/mL vs. non-smokers 358 (50-876) pg/mL, P<0.001). This was more pronounced in asthmatics (smokers, 47 (40-64) pg/mL vs. non-smokers, 530 (30-1484) pg/mL; P<0.001) than in normal subjects (smokers, 25 (0-78) pg/mL vs. non-smokers, 247 (50-656) pg/mL; P<0.01). Within each of the smoking and non-smoking groups there was no significant difference in IL-18 levels between asthmatic and normal subjects. There was no correlation between sputum IL-18 levels and any specific cell type in the sputum samples nor serum IgE levels. IL-18 mRNA expression was reduced in asthmatic smokers compared with non-smokers. IL-18 production was localized to sputum macrophages by immunocytochemistry. CONCLUSIONS: IL-18 is detectable in induced sputum samples from both asthmatic and normal subjects. Cigarette smoking significantly reduces sputum IL-18 levels. This effect is more pronounced in asthmatics than in normal subjects.

Investigation of stimulus-secretion coupling in equine sweat gland epithelia using cell culture techniques.

When sweat glands isolated from samples of horse skin were explanted and cultured under favourable conditions, they could exhibit cellular outgrowth. This growth could be maintained for 2-4 weeks and these primary cultures were then disaggregated and the resultant cell suspensions used to initiate epithelial cell lines. Secretion from intact equine sweat glands is regulated by beta 2-adrenoceptors and appears to be mediated by cyclic AMP, but there is evidence that calcium may also play a role. Adrenaline could increase the cyclic AMP content of the cultured cells and this response was mediated by beta 2-adrenoceptors. Adrenaline was also able to evoke a small increase in intracellular free calcium ([Ca2+]i) but the pharmacology of this response remains obscure. Adrenaline thus activates at least two potentially important second-messenger signalling pathways which have the capacity to interact, because adrenaline-evoked cyclic AMP formation was inhibited if [Ca2+]i was raised with ionomycin. The chloride permeability of mammalian epithelial cells characteristically rises during secretion, and adrenaline could increase chloride permeability in the cultured epithelia but the cells did not contain cyclic-AMP-dependent chloride channels and so this response was mediated by [Ca2+]i.

Temporal changes in the granulocytic responses to experimental infection of the skin of mice and sheep with Dermatophilus congolensis.

The patterns of dermal inflammatory cell response to infection with Dermatophilosis congolensis were determined in mice and sheep from histological samples taken before and at intervals after topical application of infective zoospores to ether-swabbed skin. Neutrophils, eosinophils, basophils and mast cells were identified by histochemical staining. Temporal changes in the B cell, T cell, and MHC Class II+ dendritic cell populations form part of a separate report. The filamentous stages of the bacterium were observed in the stratum corneum of both species; in the sheep they were also found in the outer layers of the living epidermis. In both species, large numbers of neutrophils and some lymphocytes penetrated the epidermis and entered the infected surface region. Within the underlying dermis there was an accumulation of dendritic cells immediately below the infected epidermis and evidence of mast cell degranulation; the basophils and eosinophils did not appear to be actively involved. The striking difference between the two species was the duration of the infection and the associated response which, in the mouse, lasted about five days in comparison with over 21 days in the sheep. Neutrophil numbers in the mouse for example were elevated by 12 h and had peaked at 60 h after infection, while in the sheep they did not peak until about 120 h.