Antirheumatic therapy is associated with reduced complement activation in rheumatoid arthritis.

BACKGROUND: The complement system plays an important role in pathophysiology of cardiovascular disease (CVD), and might be involved in accelerated atherogenesis in rheumatoid arthritis (RA). The role of complement activation in response to treatment, and in development of premature CVD in RA, is limited. Therefore, we examined the effects of methotrexate (MTX) and tumor necrosis factor inhibitors (TNFi) on complement activation using soluble terminal complement complex (TCC) levels in RA; and assessed associations between TCC and inflammatory and cardiovascular biomarkers. METHODS: We assessed 64 RA patients starting with MTX monotherapy (n = 34) or TNFi with or without MTX co-medication (TNFi±MTX, n = 30). ELISA was used to measure TCC in EDTA plasma. The patients were examined at baseline, after 6 weeks and 6 months of treatment. RESULTS: Median TCC was 1.10 CAU/mL, and 57 (89%) patients had TCC above the estimated upper reference limit (<0.70). Compared to baseline, TCC levels were significantly lower at 6-week visit (0.85 CAU/mL, p<0.0001), without significant differences between the two treatment regimens. Notably, sustained reduction in TCC was only achieved after 6 months on TNFi±MTX (0.80 CAU/mL, p = 0.006). Reductions in TCC after treatment were related to decreased C-reactive protein (CRP), erythrocyte sedimentation rate (ESR) and interleukin 6, and increased levels of total, high and low-density lipoprotein cholesterol. Similarly, baseline TCC was significantly related to baseline CRP, ESR and interleukin 6. Patients with endothelial dysfunction had higher baseline TCC than those without (median 1.4 versus 1.0 CAU/mL, p = 0.023). CONCLUSIONS: Patients with active RA had elevated TCC, indicating increased complement activation. TCC decreased with antirheumatic treatment already after 6 weeks. However, only treatment with TNFi±MTX led to sustained reduction in TCC during the 6-month follow-up period. RA patients with endothelial dysfunction had higher baseline TCC compared to those without, possibly reflecting involvement of complement in the atherosclerotic process in RA.

Hypersensitivity reaction studies of a polyethoxylated castor oil-free, liposome-based alternative paclitaxel formulation.

The commercial drug paclitaxel (Taxol) may introduce hypersensitivity reactions associated with the polyethoxylated castor oil-ethanol solvent. To overcome these problems, we developed a polyethoxylated castor oil-free, liposome-based alternative paclitaxel formulation, known as Lipusu. In this study, we performed in vitro and in vivo experiments to compare the safety profiles of Lipusu and Taxol, with special regard to hypersensitivity reactions. First, Swiss mice were used to determine the lethal dosages, and then to evaluate hypersensitivity reactions, followed by histopathological examination and enzyme-linked immunosorbent assays (ELISAs) of serum SC5b-9 and lung histamine. Additionally, healthy human serum was used to analyze in vitro complement activation. Finally, an MTT assay was used to determine the in vitro anti-proliferation activity. Our data clearly showed that Lipusu displayed a much higher safety margin and did not induce hypersensitivity or hypersensitivity-related lung lesions, which may be associated with the fact that Lipusu did not activate complement or increase histamine release in vivo. Moreover, Lipusu did not promote complement activation in healthy human serum in vitro, and demonstrated anti-proliferative activity against human cancer cells, similar to that of Taxol. Therefore, the improved formulation of paclitaxel, which exhibited a much better safety profile and comparable cytotoxic activity to Taxol, may bring a number of benefits to cancer patients.

Is cell salvage safe in liver resection? A pilot study.

STUDY OBJECTIVE: To investigate the quality of cell salvaged (CS) blood in patients undergoing hemihepatectomy (study group) and compare it with CS-blood from aortic surgery (control group). DESIGN: Observational study. SETTING: Operating room in a university hospital. MEASUREMENTS: 6 patients undergoing hemihepatectomy or aortobifemoral bypass with intraoperative blood loss of more than 800 mL. Samples were drawn from the central venous catheter, from the reservoir of a CS recovery system, and from the processed blood in each patient to determine interleukin (IL)-6, IL-8, IL-10, tumor necrosis factor (TNF), complement C3a, and the terminal complement complex C5b-9. Microbiological analysis included colony count after cultivation in aerobic and anaerobic medium as well as enrichment culture for 6 days. MAIN RESULTS: In the hemihepatectomy group, levels of IL-6, C3a, and C5b-9 were significantly higher in the reservoir than in samples obtained from the central venous catheter. After the washing procedure, levels of IL-6, C3a, and C5b-9 were lower in the liver resection group than in each patient's own plasma levels. In all patients undergoing aortobifemoral bypass and in 5 patients undergoing hemihepatectomy, blood samples were sterile or showed growth of commensal skin microflora in low numbers (coagulase-negative staphylococci or propionibacteria). In one patient in the liver resection group, we could not exclude contamination with intestinal flora. CONCLUSION: Cell salvaged blood in liver resection seems to be safe for retransfusion with respect to cytokine release and complement activation, but requires further investigation in regard to bacterial contamination.

Cyanobacterial LPS antagonist (CyP)-a novel and efficient inhibitor of Escherichia coli LPS-induced cytokine response in the pig.

Toll-like receptors are essential pattern-recognition receptors of the innate immune system. They recognize a range of conserved molecules of invading microorganisms. The innate immune system is developed to protect the host, but can be deleterious if activated uncontrolled or inappropriate, such as in sepsis with Gram-negative bacteria. New approaches for treatment, like inhibition of innate immune responses, may be beneficial for the outcome of such conditions. Toll-like receptor 4 associated with CD14 and MD-2, is the lipopolysaccharide (LPS)-receptor and one of the candidates for such intervention. We investigated the newly described cyanobacterial LPS analogue CyP as a potential inhibitor of Escherichia coli (E. coli) LPS-induced inflammatory response in porcine whole blood. Pro-inflammatory cytokines and soluble terminal complement complex, sC5b-9, were used as read-outs. CyP, in contrast to E. coli LPS, did not induce cytokine production using doses up to 1mug/mL whole blood, indicating a lack of agonistic effect of CyP. In contrast, CyP was an efficient LPS antagonist, dose-dependently and completely inhibiting E. coli LPS-induced TNF-alpha, IL-1beta and IL-8 production. CyP was a modest activator of porcine complement compared to LPS from other Gram-negative bacteria. When CyP was pre-incubated in porcine whole blood before adding whole E. coli bacteria, a modest, variable and non-significant inhibition of cytokines were seen, reaching an average inhibition of 44% for IL-1beta. We have demonstrated for the first time that the cyanobacterial LPS analogue, CyP, is an efficient inhibitor of E. coli LPS-induced cytokines in whole blood and may be a candidate for therapeutic LPS-inhibition.

Autotransfusion in coronary artery bypass grafting: disparity in laboratory tests and clinical performance.

OBJECTIVE: Autotransfusion during and after cardiac surgery is widely performed, but its effects on coagulation, fibrinolysis, and inflammatory response have not been known in detail. METHODS: Hemostatic and inflammatory markers were extensively studied in 40 coronary artery bypass patients undergoing a consistent intraoperative and postoperative autotransfusion protocol. An identical autotransfusion protocol was applied to 4916 consecutive coronary patients and the overall clinical results were evaluated in this large patient population. RESULTS: The autologous blood pooled before bypass remained nearly inactivated after storage. A slight elevation of thrombin-antithrombin complex and prothrombin fragment 1.2, as well as plasmin/alpha(2)-antiplasmin complex was found in the content of the extracorporeal circuit after surgery, indicating thrombin formation and fibrinolytic activity. Also some increase of beta-thromboglobulin was present. In the mediastinal shed blood, complete coagulation, as evidenced by the absence of fibrinogen, had taken place and all parameters described above were extremely elevated. However, no thrombin activity was detected. As for the inflammatory response, moderately increased levels of complement activation products, terminal complement complex, and interleukin-6 traced in the extracorporeal circuit reached very high levels in mediastinal shed blood. Autotransfusion of the residual extracorporeal circuit blood and the mediastinal drainage was followed by elevation of most of these markers in circulating plasma. On the other hand, no correlating harmful effects were recorded in the study patients or in the consecutive 4916 patients. Coagulation disturbances were rare and allogeneic transfusions were required in fewer than 4% of all patients. CONCLUSIONS: The hemostatic and immunologic systems were moderately activated in the autologous blood remaining in the extracorporeal circuit, whereas the mediastinal shed blood was highly activated in all aspects. However, autotransfusion had no correlating clinical side-effects and the subsequent exposure to allogeneic blood products was minimal.

Greater increase in cytokine concentration after salvage with filtered whole blood than with washed red cells, but no difference in postoperative hemoglobin recovery.

BACKGROUND: Inflammatory mediators are released in association with intraoperative and postoperative salvage of blood. Whether these mediators (cytokines) participate in the modulation of erythropoiesis or not has been investigated. STUDY DESIGN AND METHODS: Twenty-seven patients who were to undergo total knee replacement surgery were randomly assigned to postoperative blood salvage with either filtered whole blood or washed red cells. Patients with postoperative blood loss <400 mL were considered a control group. The control group did not receive any transfusions. Plasma concentrations of the anaphylatoxin C3a, the C5b-9 terminal complement complex, and the cytokines interleukins 6 and 8, hemoglobin, reticulocytes, and red cell volume fraction in the patients were repeatedly analyzed before and after surgery. RESULTS: Significantly increased concentrations of interleukin 6 appeared in all three groups, which was interpreted as a response to the surgical trauma. The increase was significantly greater in the group that received filtered whole blood after return of shed blood. The recovery of hemoglobin levels did not differ in the groups. CONCLUSION: The transfusion of filtered whole blood leads to the formation of interleukin 6 in the circulation, but postoperative hemoglobin recovery was similar in all groups.

The severity of clinical symptoms in ragweed-allergic patients is related to the extent of ragweed-induced complement activation in their sera.

We have previously reported a correlation between the extent of ragweed allergen (RWA)-induced in vitro serum complement activation and the symptom scores registered daily during the ragweed (RW)-blooming season in RW-allergic patients. The present study was performed in 22 15-17-year-old RW-allergic adolescents. Serum samples were incubated with 100 micrograms/ml RWA, and the generation of different complement activation products was measured by ELISA or RIA. Symptom scores were registered for 4 weeks during the RW-blooming season. The patients were divided according to the extent (low or high) of the generation of complement activation products, and symptom scores registered in the two groups were compared by two-way ANOVA. Significantly higher symptom scores were obtained in the high than in the low complement activation group (P values: 0.049 for C1rC1sC1inh, 0.022 for C3bBbP, 0.015 for C5b-9, 0.0001 for C3a, and 0.0008 for C5a). Similar results were obtained at the measurement performed in the sera obtained from the same patients half a year before the season (P values: 0.022 for C3bBbP, and 0.005 for C5b-9). These findings indicate that complement activation induced by the allergen may enhance the clinical symptoms of RW allergy.

Anaphylatoxin and terminal complement complexes in red cell salvage.

Thirteen patients undergoing elective orthopedic surgery were studied regarding anaphylatoxin (C3a and C5a) and terminal complement complex (TCC) formation in association with red cell salvage. The auto-transfusion equipment gave a centrifuged and washed erythrocyte fraction. The concentrations of C5a and TCC were not increased but elevated C3a levels were found in the suspension. After infusion of the erythrocyte fraction to the patient, no signs of systemic complement activation were observed. Thus, plasma levels of C3a, C5a and TCC were within the normal range in all the patients before and after autotransfusion. This study indicates that the complement system is activated in the cellsaver equipment. The washing procedure, however, seems to eliminate most of the anaphylatoxins and terminal complement complexes. No extensive systemic activation of complement seems to occur in association with autotransfusion to patients undergoing elective surgery.