The efficacy of taurolidine containing lock solutions for the prevention of central-venous-catheter-related bloodstream infections: a systematic review and meta-analysis

The incidence of central venous catheter (CVC)-related bloodstream infections is high in patients requiring a long-term CVC. Therefore, infection prevention is of the utmost importance. The aim of this study was to provide an updated overview of randomized controlled trials (RCTs) comparing the efficacy of taurolidine containing lock solutions (TL) to other lock solutions for the prevention of CVC-related bloodstream infections in all patient populations. On 15^th February 2021, PubMed, Embase and The Cochrane Library were searched for RCTs comparing the efficacy of TLs for the prevention of CVC-related bloodstream infections with other lock solutions. Exclusion criteria were non-RCTs, studies describing <10 patients and studies using TLs as treatment. Risk of bias was evaluated using the Cochrane Risk of Bias 2 tool. A random effects model was used to pool individual study incidence rate ratios (IRRs). Subgroup analyses were performed based on the following factors: CVC indication, comparator lock and bacterial isolates cultured. A total of 14 articles were included in the qualitative synthesis describing 1219 haemodialysis, total parenteral nutrition and oncology patients. The pooled IRR estimated for all patient groups together (nine studies; 918 patients) was 0.30 (95% confidence interval 0.19-0.46), favouring the TLs. Adverse events (10 studies; 867 patients) were mild and scarce. The quality of the evidence was limited due to a high risk of bias and indirectness of evidence. The use of TLs might be promising for the prevention of CVC-related bloodstream infections. Large-scale RCTs are needed to draw firm conclusions on the efficacy of TLs.

A 2% taurolidine catheter lock solution prevents catheter-related bloodstream infection (CRBSI) and catheter dysfunction in hemodialysis patients

HIGHLIGHTS

2% taurolidine catheter lock solution without additives is safe and efficient. CRBSI and dysfunction rates compare favorably against other studies in hemodialysis.

BACKGROUND

In hemodialysis patients, catheter-related bloodstream infection (CRBSI) and catheter dysfunction are common and cause significant morbidity, mortality, and costs. Catheter lock solutions reduce CRBSI and catheter dysfunction rates, but solutions containing heparin, citrate, or antibiotics are associated with adverse effects. Due to its antimicrobial and antithrombotic properties and benign safety profile, taurolidine is suitable for use in catheter lock solutions. In this study the effectiveness and safety of a catheter lock solution containing 2% taurolidine without citrate or heparin (TauroSept®, Geistlich Pharma AG, Wolhusen, Switzerland) in hemodialysis patients were investigated for the first time.

METHODS

Data from 21 patients receiving chronic hemodialysis via tunneled central venous catheters with 2% taurolidine solution as a catheter lock were analyzed in a single-center retrospective study and compared with the existing literature in a review. The primary endpoint was CRBSI rate. Secondary endpoints included catheter dysfunction, treatment, and costs; catheter technical problems, resolution, and costs; and adverse events. Data were compared to outcomes with standard lock solutions in the literature.

RESULTS

No CRBSIs occurred during the observation period of 5,639 catheter days. The catheter dysfunction rate was 0.71 per 1,000 catheter days, and the catheter dysfunction treatment costs were CHF (Swiss Franc) 543 per patient. No technical problems or adverse events related to the use of 2% taurolidine-containing catheter lock solution were observed. These results compare favorably with other catheter lock solutions.

CONCLUSIONS

A solution containing 2% taurolidine seems suitable as a hemodialysis catheter lock. In a Swiss cohort, it prevented CRBSI, limited catheter dysfunction, and was cost-efficient.

BACE inhibition causes rapid, regional, and non-progressive volume reduction in Alzheimer's disease brain

In the phase 3 EPOCH trial (Clinicaltrials.gov; NCT01739348), treatment with the BACE inhibitor verubecestat failed to improve cognition in patients with mild-to-moderate Alzheimer's disease, but was associated with reduced hippocampal volume after 78 weeks as assessed by MRI. The aims of the present exploratory analyses were to: (i) characterize the effect of verubecestat on brain volume by evaluating the time course of volumetric MRI changes for a variety of brain regions; and (ii) understand the mechanism through which verubecestat might cause hippocampal (and other brain region) volume loss by assessing its relationship to measures of amyloid, neurodegeneration, and cognition. Participants were aged 55-85 years with probable Alzheimer's disease dementia and a Mini Mental State Examination score ≥15 and ≤26. MRIs were obtained at baseline and at Weeks 13, 26, 52 and 78 of treatment. MRIs were segmented using Freesurfer and analysed using a tensor-based morphometry method. PET amyloid data were obtained with 18F-flutemetamol (Vizamyl®) at baseline and Week 78. Standardized uptake value ratios were generated with subcortical white matter as a reference region. Neurofilament light chain in the CSF was assessed as a biomarker of neurodegeneration. Compared with placebo, verubecestat showed increased MRI brain volume loss at Week 13 with no evidence of additional loss through Week 78. The verubecestat-related volumetric MRI loss occurred predominantly in amyloid-rich brain regions. Correlations between amyloid burden at baseline and verubecestat-related volumetric MRI reductions were not significant (r = 0.05 to 0.26, P-values > 0.27). There were no significant differences between verubecestat and placebo in changes from baseline in CSF levels of neurofilament light chain at Week 78 (increases of 7.2 and 14.6 pg/ml for verubecestat versus 19.7 pg/ml for placebo, P-values ≥ 0.1). There was a moderate correlation between volumetric MRI changes and cognitive decline in all groups including placebo at Week 78 (e.g. r = -0.45 to -0.55, P < 0.001 for whole brain), but the correlations were smaller at Week 13 and significant only for the verubecestat groups (e.g. r = -0.15 and -0.11, P < 0.04 for whole brain). Our results suggest that the verubecestat-associated MRI brain volume loss is not due to generalized, progressive neurodegeneration, but may be mediated by specific effects on BACE-related amyloid processes.

A Novel Selective 11β-HSD1 Inhibitor, (E)-4-(2-(6-(2,6-Dichloro-4-(Trifluoromethyl)Phenyl)-4-Methyl-1,1-Dioxido-1,2,6-Thiadiazinan-2-yl)Acetamido)Adamantan-1-Carboxamide (KR-67607), Prevents BAC-Induced Dry Eye Syndrome

Dry eye syndrome is the most common eye disease and it is caused by various reasons. As the balance of the tear film that protects the eyes is broken due to various causes, it becomes impossible to properly protect the eyes. In this study, the protective effects and underlying mechanisms of topical (E)-4-(2-(6-(2,6-dichloro-4-(trifluoromethyl)phenyl)-4-methyl-1,1-dioxido-1,2,6-thiadiazinan-2-yl)acetamido)adamantan-1-carboxamide (KR-67607), a novel selective 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1) inhibitor, were investigated in benzalkonium chloride (BAC)-induced dry eye syndrome. BAC-treated rat eyes induced significant increases in ocular surface damage, decreased corneal thickness, corneal basement membrane destruction in the conjunctival epithelium, and expression of pro-inflammatory cytokines tumor necrosis factor-α and 11β-HSD1. These effects of BAC were reversed by topical KR-67607 treatment. Furthermore, KR-67607 decreased 4-hydroxynonenal expression and increased antioxidant and mucus secretion in BAC-treated rat eyes. Taken together, a novel selective 11β-HSD1 inhibitor can prevent BAC-induced dry eye syndrome by inhibiting pro-inflammatory cytokine and reactive oxygen species expression via the inhibition of both 11β-HSD1 activity and expression.

Randomized Trial of Verubecestat for Prodromal Alzheimer's Disease

BACKGROUND

Prodromal Alzheimer's disease offers an opportunity to test the effect of drugs that modify the deposition of amyloid in the brain before the onset of dementia. Verubecestat is an orally administered β-site amyloid precursor protein-cleaving enzyme 1 (BACE-1) inhibitor that blocks production of amyloid-beta (Aβ). The drug did not prevent clinical progression in a trial involving patients with mild-to-moderate dementia due to Alzheimer's disease.

METHODS

We conducted a randomized, double-blind, placebo-controlled, 104-week trial to evaluate verubecestat at doses of 12 mg and 40 mg per day, as compared with placebo, in patients who had memory impairment and elevated brain amyloid levels but whose condition did not meet the case definition of dementia. The primary outcome was the change from baseline to week 104 in the score on the Clinical Dementia Rating Scale-Sum of Boxes (CDR-SB; scores range from 0 to 18, with higher scores indicating worse cognition and daily function). Secondary outcomes included other assessments of cognition and daily function.

RESULTS

The trial was terminated for futility after 1454 patients had been enrolled; 485 had been assigned to receive verubecestat at a dose of 12 mg per day (the 12-mg group), 484 to receive verubecestat at a dose of 40 mg per day (the 40-mg group), and 485 to receive placebo. A total of 234 patients, 231 patients, and 239 patients per group, respectively, completed 104 weeks of the trial regimen. The estimated mean change from baseline to week 104 in the CDR-SB score was 1.65 in the 12-mg group, 2.02 in the 40-mg group, and 1.58 in the placebo group (P = 0.67 for the comparison between the 12-mg group and the placebo group and P = 0.01 for the comparison between the 40-mg group and the placebo group), suggesting a worse outcome in the higher-dose group than in the placebo group. The estimated rate of progression to dementia due to Alzheimer's disease was 24.5, 25.5, and 19.3 events per 100 patient-years in the 12-mg group, the 40-mg group, and the placebo group, respectively (hazard ratio for 40 mg vs. placebo, 1.38; 97.51% confidence interval, 1.07 to 1.79, not adjusted for multiple comparisons), favoring placebo. Adverse events were more common in the verubecestat groups than in the placebo group.

CONCLUSIONS

Verubecestat did not improve clinical ratings of dementia among patients with prodromal Alzheimer's disease, and some measures suggested that cognition and daily function were worse among patients who received verubecestat than among those who received placebo. (Funded by Merck Sharp & Dohme; ClinicalTrials.gov number, NCT01953601.).

Immunomodulatory Action of Substituted 1,3,4-Thiadiazines on the Course of Myocardial Infarction

This review focuses on the biological action of the compounds from the group of substituted 1,3,4-thiadiazines on stress response and myocardial infarction. The aim of this review is to propose the possible mechanisms of action of 1,3,4-thiadiazines and offer prospectives in the development of new derivatives as therapeutic agents. It is known, that compounds that have biological effects similar to those used as antidepressants can down-regulate the secretion of proinflammatory cytokines, up-regulate the release of anti-inflammatory ones and affect cell recruitment, which allows them to be considered immunomodulators as well. The results of pharmacological evaluation, in silico studies, and in vivo experiments of several compounds from the group of substituted 1,3,4-thiadiazines with antidepressant properties are presented. It is proposed that the cardioprotective effects of substituted 1,3,4-thiadiazines might be explained by the peculiarities of their multi-target action: the ability of the compounds to interact with various types of receptors and transporters of dopaminergic, serotonergic and acetylcholinergic systems and to block the kinase signal pathway PI3K-AKT. The described effects of substituted 1,3,4-thiadiazines suggest that it is necessary to search for a new agents for limiting the peripheral inflammatory/ischemic damage through the entral mechanisms of stress reaction and modifying pro-inflammatory cytokine signaling pathways in the brain.

Randomized Trial of Verubecestat for Mild-to-Moderate Alzheimer's Disease

BACKGROUND

Alzheimer's disease is characterized by the deposition of amyloid-beta (Aβ) plaques in the brain. Aβ is produced from the sequential cleavage of amyloid precursor protein by β-site amyloid precursor protein-cleaving enzyme 1 (BACE-1) followed by γ-secretase. Verubecestat is an oral BACE-1 inhibitor that reduces the Aβ level in the cerebrospinal fluid of patients with Alzheimer's disease.

METHODS

We conducted a randomized, double-blind, placebo-controlled, 78-week trial to evaluate verubecestat at doses of 12 mg and 40 mg per day, as compared with placebo, in patients who had a clinical diagnosis of mild-to-moderate Alzheimer's disease. The coprimary outcomes were the change from baseline to week 78 in the score on the cognitive subscale of the Alzheimer's Disease Assessment Scale (ADAS-cog; scores range from 0 to 70, with higher scores indicating worse dementia) and in the score on the Alzheimer's Disease Cooperative Study Activities of Daily Living Inventory scale (ADCS-ADL; scores range from 0 to 78, with lower scores indicating worse function).

RESULTS

A total of 1958 patients underwent randomization; 653 were randomly assigned to receive verubecestat at a dose of 12 mg per day (the 12-mg group), 652 to receive verubecestat at a dose of 40 mg per day (the 40-mg group), and 653 to receive matching placebo. The trial was terminated early for futility 50 months after onset, which was within 5 months before its scheduled completion, and after enrollment of the planned 1958 patients was complete. The estimated mean change from baseline to week 78 in the ADAS-cog score was 7.9 in the 12-mg group, 8.0 in the 40-mg group, and 7.7 in the placebo group (P=0.63 for the comparison between the 12-mg group and the placebo group and P=0.46 for the comparison between the 40-mg group and the placebo group). The estimated mean change from baseline to week 78 in the ADCS-ADL score was -8.4 in the 12-mg group, -8.2 in the 40-mg group, and -8.9 in the placebo group (P=0.49 for the comparison between the 12-mg group and the placebo group and P=0.32 for the comparison between the 40-mg group and the placebo group). Adverse events, including rash, falls and injuries, sleep disturbance, suicidal ideation, weight loss, and hair-color change, were more common in the verubecestat groups than in the placebo group.

CONCLUSIONS

Verubecestat did not reduce cognitive or functional decline in patients with mild-to-moderate Alzheimer's disease and was associated with treatment-related adverse events. (Funded by Merck; ClinicalTrials.gov number, NCT01739348 .).

Catheter lock solutions: it's time for a change

In recent years, the number of patients on hemodialysis (HD) with central vascular catheters (CVCs) has grown. However, CVC use is often associated with an important risk for catheter related bloodstream infections (CRBI) and inadequate dialysis due to flow problems. In this study, we reviewed alternative solutions to heparin for locking HD CVCs. Several experiences have demonstrated that trisodium citrate (TSC) (30–47%), citrate (4%) and taurolidine (1.35%) solutions are effective and safe for the prevention of CRBI, while heparin stimulates biofilm formation. High citrate (47%) concentrations can also provide significant advantages in reducing catheter clotting, but controlled studies with larger populations are necessary to confirm and to extend the use of such solutions in clinical practice. Side effects with high sodium citrate concentrations have been reported only immediately after locking, the symptoms are probably caused by a temporary drop in ionized calcium and magnesium, but it is evident that these solutions should only be used by skilled and authorized personnel, with a rigorous protocol.

Redox-directed cancer therapeutics: Taurolidine and Piperlongumine as broadly effective antineoplastic agents (review)

Targeting the oxygen stress response pathway is considered a promising strategy to exert antineoplastic activity in a broad spectrum of tumor types. Supporting this view, we summarize the mechanism of action of Taurolidine and Piperlongumine, two antineoplastic agents with strikingly broad tumor selectivity. Taurolidine enhances the oxidative stress (ROS) selectively in tumor cells. Its cytotoxicity for various tumor cells in vitro and in vivo, which includes tumor stem cells, is based on the induction of programmed cell death, largely via apoptosis but also necroptosis and autophagy. The redox-directed mechanism of action of Taurolidine is apparent from the finding that reducing agents e.g., N-acetylcysteine or glutathione impair its cytotoxicity, while its effectiveness is enhanced by agents which inhibit the cellular anti‑oxidant capacity. A similar redox-directed antineoplastic action is shown by Piperlongumine, a recently described experimental drug of plant origin. Taurolidine is particularly advantageous in surgical oncology as this taurine-derivative can be applied perioperatively or systemically with good tolerability as shown in initial clinical applications.

Taurolidine lock solutions for the prevention of catheter-related bloodstream infections: a systematic review and meta-analysis of randomized controlled trials

Background

Catheter-related bloodstream infections (CRBSIs) are a significant cause of morbidity and mortality in critically ill patients, contributing to prolonged hospital stays and increased costs. Whether taurolidine lock solutions (TLS) are beneficial for the prevention of CRBSIs remains controversial. In this meta-analysis, we aim to assess the efficacy of TLS for preventing CRBSIs.

Methods

We conducted a systematic search of PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials. Eligible studies included randomized controlled trials that reported on the effects of TLS for preventing CRBSIs. The primary outcome in these studies was catheter-related bloodstream infections, with microbial distribution of CRBSI and catheter-associated thrombosis as secondary outcomes. Data were combined using random-effects models owing to significant clinical heterogeneity.

Results

Six randomized controlled trials (RCTs) conducted from 2004 through 2013 involving 431 patients and 86,078 catheter-days were included in the review. TLS were significantly associated with a lower incidence of CRBSIs when compared to heparin lock solutions (Risk Ratio [RR], 0.34; 95% Confidence Interval [CI], 0.21–0.55). Use of TLS significantly decreased the incidence of CRBSIs from gram-negative (G−) bacteria (P = 0.004; RR, 0.27; CI, 0.11–0.65), and was associated with a non-significant decrease in gram-positive (G+) bacterial infections (P = 0.07; RR, 0.41; CI, 0.15–1.09). No significant association was observed with TLS and catheter-associated thrombosis (RR, 1.99; CI, 0.75–5.28).

Conclusions

The use of TLS reduced the incidence of CRBSIs without obvious adverse effects or bacterial resistance. However, the susceptibility of G+ and G- bacteria to taurolidine and the risk for catheter-associated thrombosis of TLS are indeterminate due to limited data. The results should be treated with caution due to the limited sample sizes and methodological deficiencies of included studies. Therefore, additional well-designed and adequately powered RCTs are needed to confirm these findings.

Innate immune responses to Stenotrophomonas maltophilia in immunocompromised pediatric patients and the effect of taurolidine

BACKGROUND

Stenotrophomonas maltophilia is an emerging pathogen causing invasive infections in immunocompromised pediatric patients, including neonates and pediatric oncology patients. Information on innate immune responses to S. maltophilia and its potential modulation are scarce.

METHODS

We established an in vitro S. maltophilia whole blood sepsis model and studied the proinflammatory cytokine production of CD14-positive cells by flow cytometry. We compared the cytokine expression of term newborns (n = 13) and healthy adults (n = 10) and investigated in vitro responses of pediatric oncology patients after recovery from neutropenia (n = 10) with healthy adults (n = 10). We further evaluated the immunomodulatory role of the amino-acid derivative taurolidine in our in vitro sepsis model.

RESULTS

Proinflammatory cytokine responses to S. maltophilia were largely diminished in the neonatal population. No remarkable differences were noted for cytokine responses between pediatric oncology patients and healthy controls. Taurolidine inhibited immunoglobulin (IL)-6, IL-8 and tumor necrosis factor-alpha expression in a dose dependent-fashion in both, pediatric oncology patients and healthy controls.

CONCLUSION

Deficient immune responses to S. maltophilia require optimized prevention strategies against infection in immunocompromised patients, including neonates. Taurolidine may be an effective immunomodulatory agent in a clinical setting.

Approaches to prolong the use of uncuffed hemodialysis catheters: results of a randomized trial

BACKGROUND

Use of uncuffed catheters (UCs) in hemodialysis patients is common practice. An antibiotic lock has been recommended to prevent catheter-related bacteremia (CRB), although insufficient data are available about the appropriate antimicrobial agent and dose with prolonged use of UCs.

METHODS

This open-label randomized study was conducted to compare gentamicin/heparin (group A) and taurolidine/citrate (group B), as catheter-lock solutions, in 119 chronic hemodialysis patients in whom a total of 150 UCs were placed. A well-matched historical control group (heparin) included 67 UCs in 58 patients (group C).

RESULTS

CRB episodes developed in 6 and 8 patients in groups A and B, respectively, significantly fewer than in group C (20 patients). Cumulative CRB-free catheter survival at 90 days was 82% for A and 78% for B, which is significantly higher than the 26% for C. Similar Gram-positive infection rates were found in all groups. The Gram-negative infection rate was significantly lower in B compared to C. No significant differences in thrombosis rates were observed between the groups.

CONCLUSIONS

Gentamicin/heparin and taurolidine/citrate, used for locking UC, were similarly effective at preventing CRB and catheter thrombosis for up to 3 months, until a functional permanent vascular access became available. Both antimicrobial lock solutions were superior to heparin in CRB prevention with similar thrombosis rates.

Effectiveness of Topical TaurolidineversusCiprofloxacin, Ofloxacin, and Fortified Cefazolin in a RabbitStaphylococcusaureusKeratitis Model

PURPOSE

Taurolidine is a broad-spectrum, non antibiotic antimicrobial agent, not previously tested against the common causes of bacterial keratitis. This study, employing an experimental rabbit model of Staphylococcus aureus keratitis, investigated the effectiveness of topical taurolidine in reducing the number of bacteria, and its effectiveness was compared with topical ciprofloxacin, ofloxacin, and 5% cefazolin.

METHODS

The right corneas of all rabbits were intrastromally injected with 100 colony-forming units of Staphylococcus aureus ATCC strain 25923. The animals were divided into the following seven groups: Group 1 (6 rabbits) received taurolidine, group 2 (6 rabbits) received ciprofloxacin, group 3 (6 rabbits) received ofloxacin, group 4 (6 rabbits)received cefazolin, group 5 (5 rabbits) received polyvinylpyrrolidone (vehicle),group 6 (4 rabbits) received sterile water, and group 7 (4 rabbits) was left un-treated (control group). The eyes were topically treated every 30 min with the above-mentioned substances from 4 to 9 h postinjection. One hour after the last drop administration (at 10 h postinjection), signs of inflammation were scored in a masked fashion by slit-lamp examination. Then, their corneas were processed. The number of colony-forming units (cfu) per cornea in all eyes was also determined.

RESULTS

All antimicrobial (taurolidine, ciprofloxacin, ofloxacin, and cefazolin) treatments significantly reduced cfu numbers and slit-lamp examination scores compared with untreated eyes, eyes that received the vehicle, or eyes with sterile water (all p values <0.05). Regarding cfu numbers, although taurolidine therapy was significantly less effective than ciprofloxacin or ofloxacin,there was no significant difference between taurolidine and cefazolin groups.However, taurolidine had similar clinical examination scores with the other antimicrobials, while it had lower scores than the vehicle, sterile water, or un-treated eyes.

CONCLUSIONS

The results obtained in this study suggest that topicaltaurolidine is an effective, novel ocular chemotherapeutic agent for the therapy of rabbit experimental Staphylococcus aureus keratitis. This drug may be a useful and promising ocular antimicrobial.

Taurolidine and povidone-iodine induce different types of cell death in malignant pleural mesothelioma

Taurolidine and povidone-iodine (PVP-I) are used in every day clinical practice, taurolidine as a broad spectrum antibiotic, and PVP-I as an antiseptic. The type of cell death induced in malignant pleural mesothelioma (MPM) cell lines by these agents was compared, and their ability to sensitize to chemotherapy assessed. Both taurolidine and PVP-I inhibited MPM cell growth after 7.5min incubation, but taurolidine was more effective at later time points and was more specific towards tumour cells than PVP-I. Taurolidine induced death by caspase-dependent and independent mechanisms, whereas in contrast, PVP-I induced a necrotic phenotype that was not caspase-dependent. Interestingly, both taurolidine and PVP-I induced the production of reactive oxygen intermediates and decreased mitochondrial membrane permeability, and cell death was inhibited by the oxygen scavenger N-acetyl cysteine. Taurolidine but not PVP-I treatment resulted in p53 activation in 2/3 MPM cell lines and a decrease in the protein levels of survivin, Bcl-2 and Mcl-1. Survivin also decreased in response to PVP-I whereas Bcl-xL remained unaffected by both treatments. Targeting of Bcl-xL with siRNA sensitized MPM cells to taurolidine and taurolidine treatment sensitized MPM cells to cisplatin-induced apoptosis. In conclusion, taurolidine and PVP-I are both cytotoxic to human MPM cells at early and late time points and induce reactive oxygen intermediate production. Taurolidine induces apoptosis and necrosis, activates p53 and sensitizes cells to cisplatin, whereas PVP-I inhibits cell growth via necrosis. Both agents are promising candidates for use in local treatment within multimodality concepts for MPM.

Anti-inflammatory effects of taurine derivatives (taurine chloramine, taurine bromamine, and taurolidine) are mediated by different mechanisms

In this study, in an animal model of zymosan-induced peritonitis we have tested anti-inflammatory properties of Taurolidine (TRD), a synthetic derivative of taurine. In vitro, the effect of TRD and HOCl treated TRD on peritoneal macrophages was compared with that of TauCl. We report that locally administered TRD (Taurolin) shows strong anti-inflammatory properties. TRD inhibits vascular permeability increased by inflammatory stimuli; it also significantly attenuates the influx of neutrophils into the peritoneal cavity, as well as the production of pro-inflammatory cytokines (TNF-alpha, IL-6) by peritoneal exudate cells. Chlorination of TRD resulted in the formation of chloramine (TRD-Cl), as confirmed by characteristic UV spectra. Both TRD and TRD-Cl, more effectively than TauCl, inhibited the production of IL-6 by stimulated macrophages. The effect was not dependent on its well-known anti-endotoxin activity since TRD inhibited cytokine production by macrophages stimulated with either LPS or IFN-gamma. Finally, we report that anti-inflammatory activities of TRD and taurine haloamines are mediated by different mechanisms. TRD, in contrast to TauCl and TauBr, does not induce expression of HO-1, a stress inducible enzyme with strong anti-inflammatory properties.

Local recurrence model of malignant pleural mesothelioma for investigation of intrapleural treatment

OBJECTIVE

Local recurrence remains a major problem in the treatment of malignant pleural mesothelioma. The aim of the underlying study was to establish a standardised local recurrence model in rats which enables to study different intrapleural therapies.

MATERIALS AND METHODS

Fifty microlitre containing 1 x 10(6) cells of a syngeneic rat malignant mesothelioma cell line (II-45), established from mesothelioma in Fischer 344 rats exposed to asbestos, were inoculated subpleurally via a left-sided thoracotomy. Tumour size was assessed 6 days later and the tumour nodule completely resected. Evaluation of recurrence at the resection site was performed after 10 days (n=6) and 6 days (n=6). The recurrent nodule was histopathologically confirmed. In a second experiment, this new recurrence model was evaluated for the effect of intrapleural therapy with different agents: 4 ml of cisplatin-solution (100mg(2)/kg BW), cisplatin combined with the fibrin-based sealant Vivostat, 4 ml taurolidine 2%, repeated injection of 1 microg of the chemokine CCL-19 at the tumour site and 4 ml povidone-iodine in a dilution 1:10. In a control group, the chest cavity was filled with 4 ml 0.9% NaCl. The primary endpoint was the extent of tumour recurrence.

RESULTS

Six days after inoculation, all animals presented a standardised tumour nodule at the injection site of a mean diameter of 5.1 (+/-0.8)mm. Evaluation of the recurrence after 10 days showed a relapse directly at the resection site, but additional tumour nodules on the ipsi- and contralateral chest wall were found and histologically confirmed. The animals that were sacrificed 6 days after resection of the tumour nodule showed a recurrence only at the resection site with no macroscopic or microscopic evidence of other tumour. Resection of the tumour nodule combined with intrapleural application of the different agents lead to clear reduction of recurrence. The strongest effect was observed after intrapleural application of cisplatin-Vivostat with significant decrease of the longest, widest and thickest diameter of the recurrence.

CONCLUSIONS

With this new recurrence model for investigation of malignant pleural mesothelioma in rats, we were able to investigate new intrapleural therapies after pneumonectomy. The intrapleural application of cisplatin-Vivostat significantly reduced the extent of local recurrence.

Instillation of taurolidine/heparin after laparotomy reduces intraperitoneal tumour growth in a colon cancer rat model

OBJECTIVE

To investigate whether irrigation of the abdominal cavity after laparotomy for caecum resection with taurolidine/heparin or adhesion prophylactic substances reduces intraperitoneal tumour growth or the local recurrence rate in a colon carcinoma rat model.

METHODS

60 BDIX rats underwent caecum resection after intraperitoneal inoculation of 1 x 10(4) colon carcinoma cells (DHD/K12/TRb). Intergel, Interceed, taurolidine/heparin or NaCl 0.9% were intraperitoneally applied after randomisation. Finally, the total number and total weight of intraperitoneal metastases were determined as well as the adhesion score according to Moreno. Metastatic tissue was examined histologically and immunohistochemically (E-cadherin, CD44, beta(1)-integrin).

RESULTS

Taurolidine/heparin significantly reduced not only the total number (3 vs. 11 in the control group) but also the total weight (65 vs. 330 mg) of intraperitoneal metastases in comparison to the control group (p = 0.003 and p = 0.005). E-Cadherin expression in the metastatic tissue of animals treated with taurolidine/heparin was significantly decreased (p = 0.016).

CONCLUSION

Taurolidine/heparin effectively reduces intraperitoneal tumour growth when used as an intraoperative lavage. These results represent a good rationale for intraoperative adjuvant irrigation with taurolidine/heparin during resection of colon cancer.

Is Taurolidine a candidate for treatment of rheumatoid arthritis?

OBJECTIVE

To study the therapeutic potential of taurolidine (TRD), a derivative of taurine with known anti-inflammatory and anti-proliferative properties, in various experimental models of synovitis.

METHODS

In vitro: fibroblast-like synoviocytes (RA FLS) isolated from the synovial tissue of patients with rheumatoid arthritis (RA) were cultured in the presence of either TRD or polyvinylpyrrolidine (PVP), the pharmaceutical stabilizer of TRD, which was used as a control. Proliferation of RA FLS and cytokine (IL-6 and IL-8) release were measured. In vivo: (A). The effect of systemic TRD treatment on the development of collagen-induced arthritis (CIA) in female DBA1/J mice was investigated. Mice were treated either with intraperitoneal injections of 1 ml of 2% Taurolin Boehringer Ingelheim (TRD +PVP) or with PVP as placebo. The incidence of arthritis, myeloperoxidase (MPO) activity in periarticular tissue, as well as serum concentration of IgG specific to collagen II (IgG alphaCII) were determined. (B). The effect of intra-articular TRD treatment was studied in rabbits with antigen-induced monoarthritis (AIA). After the induction of AIA of right knees rabbits were treated either with intra-articular injections of 0.5 ml of 2% Taurolin or 0.5ml PVP ( placebo). The animals were examined for clinical signs of arthritis and diameter of joints was measured. After termination of the experiment, the arthritic knees were examined and histopathology of the joints was assessed. In addition, serum amyloid A (SAA) concentration was measured.

RESULTS

n vitro: TRD exerted cytotoxic effect on RA FLS when applied at concentrations >100 microM. TRD at non-cytotoxic concentrations, inhibited PDGF-triggered RA FLS proliferation, reduced IL-1beta - stimulated production of IL-6 and slightly decreased intracellular content of IL-8. In vivo: (A). Intraperitoneal treatment with Taurolin significantly reduced the incidence (30%) of CIA when compared to the control mice (79%). However, Taurolin failed to control the development of CIA in mice with high serum level of IgG alphaCII (>1000 U).(B). Intra-articular application of 2% Taurolin resulted in amelioration of AIA in all treated rabbits (reduced diameter of arthritic joints and smaller rise of SAA level as compared to the control animals). Histopathologic evaluation revealed pannus formation in both groups and extensive necrotic lesions of synovial tissue treated with TRD, suggesting synoviorthesis-like effect.

CONCLUSION

Results from AIA and from in vitro RA FLS studies suggest that intra-articular administration of TRD could be used as a "pharmacological scalpel" to remove the inflamed synovium. Our data confirmed anti-inflammatory and anti-proliferative properties of TRD in all experimental models encouraging further studies which should evaluate its therapeutic potential in RA.

Hyaluronic Acid/Carboxymethylcellulose Membrane Barrier versus Taurolidine for the Prevention of Adhesions to Polypropylene Mesh

BACKGROUND

A hyaluronic acid/carboxymethylcellulose (HA/CMC) membrane is an effective measure to prevent polypropylene mesh induced adhesions. We hypothesized that taurolidine 2% solution might be a cost-effective alternative to decrease adhesion formation.

MATERIALS AND METHODS

Twenty-four rats were randomized into three groups: mesh alone (group 1), mesh + taurolidine 2% (group 2), and mesh + HA/CMC (group 3). Polypropylene mesh (4 cm2) was used to repair surgically induced anterior abdominal wall defects. Taurolidine 2%or a HA/CMC membrane was used as an antiadhesive measure. The animals were sacrificed 6 weeks after the operation, and adhesions to the prosthetic material were evaluated with digital image analysis.

RESULTS

Group 1 (mesh alone) had the highest adhesion ratio (58.5 +/- 4.8%) compared with groups 2 and 3 (p < 0.05). The differences between groups 2 (mesh + taurolidine 2%; adhesion ratio 42.9 +/- 1.6%) and 3 (mesh + HA/CMC; adhesion ratio 40.3 +/- 3.0%) were not significant (p > 0.05).

CONCLUSIONS

The animals of both treatment groups (2 and 3) had lower adhesion ratios compared with the controls (group 1). In particular, the HA/CMC membrane did not present with a superior antiadhesive effect compared with taurolidine. Therefore, taurolidine is a cost-effective alternative to HA/CMC membranes when a polypropylene mesh is used in direct contact with the abdominal viscera.

Co-immunotherapy with interleukin-2 and taurolidine for progressive metastatic melanoma

BACKGROUND

Recombinant interleukin-2(rIL-2) therapy in metastatic melanoma is limited by toxicities, particularly vascular leak syndrome(VLS). Taurolidine potentiates the anti-neoplastic effects of IL-2 while reducing its associated endothelial cell dysfunction in experimental settings. We hypothesized that co-administration of rIL-2 with taurolidine could enhance tolerability without weakening effectiveness.

METHODS

Eleven patients with progressive metastatic melanoma received high-dose rIL-2 with co-infusion of taurolidine. Patients were monitored for the development of toxicities and evidence of response.

RESULTS

Ten patients tolerated twenty-nine courses of high-dose rIL-2 without dose-reduction. Most toxicities were low-grade. No patient developed VLS. Seven patients died from disease progression. Two had complete clinical and radiological responses to treatment. Two patients remain alive despite evidence of disease progression a mean of 17.5 months after diagnosing metastatic disease.

CONCLUSION

Co-administration of taurolidine with high-dose rIL-2 in stage IV melanoma patients appears to greatly enhance the tolerability of this regime without diminishing its therapeutic value.

Towards Selective Kir6.2/SUR1 Potassium Channel Openers, Medicinal Chemistry and Therapeutic Perspectives

ATP sensitive potassium (K(ATP)) channels have important functions in neuroendocrine tissue, in smooth and skeletal muscle and in the heart. In pancreatic beta cells the K(ATP) channels, which are formed by 4 ion channels (Kir6.2) and 4 regulatory sulfonylurea receptors (SUR1), control the glucose stimulated release of insulin. The Kir6.2/SUR1 K(ATP) channels are also present in the brain and in other neuroendocrine tissues. Blockers of Kir6.2/SUR1 channels, e.g. glibenclamide and repaglinide stimulate release of insulin and are used for treatment of type 2 diabetes. Openers of Kir6.2/SUR1 channels, e.g. diazoxide, have in contrast only found limited clinical use in treatment of hypersecretion of insulin associated with certain tumours (insulinoma) and genetic disorders (persistent hyperinsulinemia and hypoglycemia of infancy, PHHI). Recent studies have however, indicated that openers of Kir6.2/SUR1 channels could be useful in treatment of e.g. metabolic disorders and diseases of the CNS. The clinical use of diazoxide has been hampered by its lack of potency and selectivity giving rise to side effects, such as oedema and hirsutism and new selective openers of Kir6.2/SUR1 channels have been pursued. This has provided several structurally diverse series, which include 1,2,4-thiadiazine 1,1-dioxide derivatives, like BPDZ 62, BPDZ 73, NNC 55-0462, NNC 55-0118 and NN414, cyanoguanidines, nitropyrazoles and 4-sulfamoylphenylbenzamides. NN414 has been shown to be a potent and Kir6.2/SUR1 selective K(ATP) channels opener, which inhibits glucose stimulated insulin release in vitro and in vivo and which has beneficial effects on glucose homeostasis in preclinical and clinical studies.

Taurolidine–a new drug with anti-tumor and anti-angiogenic effects

Taurolidine [bis(1,1-dioxoperhydro-1,2,4-thiadiazinyl-4)-methane (TRD)], a product derived from the aminosulfoacid taurin, was first described as an anti-bacterial substance. It was mainly used in the treatment of patients with peritonis as well as antiendoxic agent in patients with systematic inflammatory response syndrome. Meanwhile, quite interesting new experimental findings elucidated several new mechanisms concerning not only antibiotic but also anti-tumor effects. TRD significantly reduces the pathogenicity of prokaryotes, leading to a degeneration of the bacterial wall, and binds free lipoplysaccharides (LPSs) and exotoxins. Furthermore syntheses of tumor necrosis factor-a and interleukin-1b are reduced in LPS-stimulated human macrophages in a dose dependent manner. Tumor angiogenesis is promoted by enhanced expression of all these endogenous angiogenic factors, indicating an anti-angiogenetic effect of TRD. Tumor angiogenesis has a key role in tumor growth. TRD additionally inhibits tumor cell growth by a mitochondrial cytochrome c-dependent apoptotic mechanism, has a direct and elective effect on glial and neuronal brain tumor cells via Fas-ligand-mediated cell death, and inhibits protein synthesis at an early phase of translation, which might explain its various apoptotic effects. Subsequent to these experimental observations, TRD has shown encouraging clinical results after intravenous administration in patients with gastrointestinal malignancies and tumors of the central nerve system. A remarkable experimental observation that comes to complete the above-mentioned findings is the low toxicity on leukopoiesis and erythropoiesis as well as on kidney and liver function in animal models. Several other data confirm low toxicity of the agent after its clinical administration in humans. Prospective clinical studies are currently investigating the efficacy of TRD on local and metastatic tumor growth in different malignancies.

Impact of taurolidin and octreotide on liver metastasis and lipid peroxidation after laparoscopy in chemical induced ductal pancreatic cancer

BACKGROUND

There is controversial discussion whether metastasis initiated by laparoscopy with carbon dioxide might be prevented by instillation of taurolidin or radical scavengers like the somatostatin analogue Octreotide. Therefore we evaluated the effects of laparoscopic lavage with taurolidin and Octreotide on liver metastasis after staging laparoscopy in ductal pancreatic cancer.

METHODS

In 60 Syrian hamsters pancreatic adenocarcinoma was induced by weekly subcutanous injection of 10 mg N-nitrosobis-2-oxopropylamin/kg body weight for 10 weeks. In the 16th week laparoscopic staging biopsy by use of carbon dioxide was performed. Finally animals underwent abdominal irrigation with saline (gr.1, n = 20), taurolidin (0.5%) (gr.2, n = 20) or Octreotide (gr.3, n = 20). In week 25 animals were sacrificed, pancreas and liver were analysed.

RESULTS

Size of pancreatic carcinomas was decreased in the taurolidin gr. compared to the other two groups. Furthermore the number of liver metastasis per animal was reduced after lavage with taurolidin (2 +/- 2) and Octreotide (2.5 +/- 2) compared to saline irrigation (4 +/- 4) (p < 0.05). Additionally the incidence of port site metastases was significantly reduced in the taurolidin group. Activity of antioxidative enzyme superoxide dismutase (SOD) was increased while concentration of products of lipidperoxidation was decreased in non-metastatic liver after taurolidin irrigation compared to saline or Octreotide irrigation.

CONCLUSIONS

Taurolidin irrigation during laparoscopy might be a new concept to reduce the number of liver metastasis and port site metastases in pancreatic cancer.

Peritoneal taurolidine lavage in children with localised peritonitis due to appendicitis

Despite aggressive surgical treatment, rational antibiotic therapy, and modern intensive care, generalised peritonitis remains a major threat in the paediatric age group. Several adjuvant strategies such as peritoneal saline lavage and peritoneal drainage have been utilised. Taurolidine, derived from the amino acid taurine, has bactericidic, antiendotoxic, and antiinflammatory properties. It has been introduced previously for intraoperative peritoneal lavage in treating peritonitis in adults. The aim of our study was to evaluate the effect of peritoneal taurolidine lavage on the clinical course and serological inflammation markers in children with perforated appendicitis and localised peritonitis. A series of 27 children presenting with appendicitis between January 1999 and July 2001 were included in the study after parental informed consent. All patients underwent open appendectomy. Taurolidine peritoneal lavage was applied in 15 randomly selected children (eight girls and seven boys; mean age 10 years and 10 months). Twelve children received saline peritoneal lavage and served as the control group (six girls and six boys; mean age 9 years and 7 months). Blood was taken preoperatively and on postoperative days 1, 3, 7, and 14. Full blood cell count, C-reactive protein, endotoxin, interleukin-1, interleukin-6, soluble interleukin-2 receptor, tumour necrosis factor alpha, and procalcitonin were investigated to evaluate the serological course of inflammation. Both groups initially presented with severe inflammation as evidenced clinically and serologically. The clinical postoperative course was uneventful in 13/15 patients in the treatment group and 10/12 patients in the control group. The remaining patients presented complications: intraperitoneal abscess or early postoperative bowel obstruction. With regard to the serological inflammatory parameters, no significant differences were found between the two groups except for the soluble interleukin-2-receptor on the 7th postoperative day. In conclusion, the expected reduction of endotoxin levels and inflammatory activity in the treatment group was not evident. A significant advantage of adjuvant peritoneal taurolidine lavage in the surgical therapy of children with localised peritonitis due to appendicitis could not be shown in our study.

Effects of increasing doses of a bolus injection and an intravenous long-term therapy of taurolidine on subcutaneous (metastatic) tumor growth in rats

BACKGROUND

Experimental studies have shown that taurolidine suppresses intraperitoneal tumor growth following local application in rats. In opposite, a single intravenous therapy affected neither intraperitoneal nor subcutaneous growth of malignancies. Thus, an intravenous long-term therapy with taurolidine was investigated in rats after administration of a subcutaneous tumor load. VEGF and TNFalpha production and their effects on tumor growth have not been elucidated so far.

METHODS

VEGF and TNFalpha levels of rat colon adenocarcinoma cells (DHD/K12/TRb) were analyzed in the supernatant undergoing treatment of increasing taurolidine doses in vitro. Besides the cell experiments rats were treated intravenously. At the beginning of the operation, 10 000 colon adenocarcinoma cells were applied subcutaneously at the back of the rats. Then the animals (n = 80, BD IX rats) were randomized into eight groups and underwent a standardized midline laparotomy for 30 min. At the end of the operation the animals were given either a bolus (1 ml Ringer's solution) or a long-term intravenous therapy (7 days, eight-hourly 1 ml 1%, 2%, or 3% taurolidine) were performed. For long-term therapy, a jugularis vein port catheter system was placed and left for 1 week. The influence on subcutaneous tumor growth, animal growth, general side effects and leukocyte/granulocyte levels were analyzed. Total tumor weights were determined 4 weeks after cell application.

RESULTS

The VEGF and TNFalpha levels decreased rapidly after taurolidine therapy with low doses in vitro. The subcutaneous tumor growth showed a downtrend of tumor weight (P = 0.075) with a statistical significance in solid tumor counts (P = 0.04) at the back of the animals. A slight and temporary depression in animal growth was observed only in long-term therapy groups. Independent of the therapeutic agents and the application forms, the operation itself caused a slight leukopenia shortly after the operation compensated by a moderate leukocytosis in the following course. Fast injections of taurolidine led to a reduction of breathing rate.

CONCLUSIONS

Only the intravenous long-term therapy of 3% taurolidine led to a slight downregulation in subcutaneous tumor growth. The changes of leukocyte counts were not affected by taurolidine. Fast injections have to be avoided. The findings prompted us to start new experiments to determine the influence of increasing doses of taurolidine on progressive tumor growth in rats.

Taurolidine is effective in the treatment of central venous catheter-related bloodstream infections in cancer patients

Taurolidine is an antimicrobial agent that was originally used in the local treatment of peritonitis and was shown to be effective in the prevention of catheter-related bloodstream infections (CR-BSI). In this pilot study, we used taurolidine solution as an intravenous (i.v.) lock into the totally implantable intravascular devices of 11 consecutive oncological patients with catheter-related bloodstream infections not responding to systemic antimicrobial chemotherapy. All patients recovered completely from the infection. No adverse drug effects were seen. Three patients were successfully retreated for a recurrent infection. Our data suggest a beneficial role of taurolidine i.v. lock for the therapy of catheter-related bloodstream infections in oncological patients. Taurolidine i.v. lock application is feasible and could especially be useful in infections resistant to antibiotic chemotherapy.

Dialysis catheter-related bacteremia: treatment and prophylaxis

Catheter-related bacteremia is a major cause of morbidity among hemodialysis patients. This article reviews the medical literature regarding the treatment and prophylaxis of catheter-related bacteremia. Bacterial biofilm that forms in the catheter lumen is the source of catheter-related bacteremia. Treatment with systemic antibiotics alone fails to definitively eradicate the infection in most patients. Catheter-related bacteremia can be managed by either catheter removal with delayed placement of a new catheter or exchange of the infected catheter with a new catheter over a guidewire. More recent studies suggested that instillation of an antibiotic-anticoagulant lock into the catheter lumen, as an adjunct to systemic antibiotic therapy, can cure approximately two thirds of catheter-related bacteremias without requiring catheter replacement. The frequency of catheter-related bacteremia may be reduced by using tunneled, rather than nontunneled, dialysis catheters and strict aseptic technique. In addition, several pharmacological measures may be useful for prophylaxis against catheter-related bacteremia. These include application of an antimicrobial ointment (mupirocin or polysporin [Pfizer, New York, NY]) to the catheter exit site or instillation of an antimicrobial solution (gentamicin or taurolidine) into the catheter lumen. Subcutaneous dialysis devices do not reduce the frequency of catheter-related bacteremia unless an antimicrobial solution is instilled into the device. The development and widespread adoption of effective approaches to the treatment and prophylaxis of catheter-related bacteremia will dramatically reduce the morbidity and economic burden associated with this complication.

Intravitreal taurolidine against experimental Staphylococcus epidermidis endophthalmitis in rabbits

PURPOSE

Taurolidine is a broad spectrum, non-antibiotic antimicrobial agent, not previously tested against infectious endophthalmitis. The efficacy of intravitreal taurolidine in the treatment of experimental Staphylococcus epidermidis endophthalmitis was evaluated and compared with vancomycin in a rabbit model.

METHODS

The right eyes of 34 albino rabbits were infected with an intravitreal inoculum of S. epidermidis (10(5) colony-forming units/0.1 ml). The right eyes of four rabbits (group 7) were not infected and served as uninfected controls. 24 hours after inoculation of bacteria the animals were divided into the following treatment groups: group 1 (7 rabbits) received intravitreal taurolidine at 24 hours and group 2 (7 rabbits) received at 48 hours. Group 3 (7 rabbits) received vancomycin at 24 hours and group 4 (7 rabbits) at 48 hours. Group 5 (3 rabbits) received polyvinylpyrrolidone at 24 hours and group 6 (3 rabbits) at 48 hours. Clinical scoring was performed at 24, 48 and 72 hours. At 72 hours post inoculation, vitreous samples were collected for quantitative microbiological studies and then, the eyes were enucleated for histopathological scorings.

RESULTS

The clinical and histopathological examinations revealed significant amelioration of inflammation in eyes treated with taurolidine and vancomycin when compared with polyvinylpyrrolidone. The eyes treated with taurolidine also had significantly lower colony forming units than the eyes treated with polyvinylpyrrolidone and taurolidine rendered many eyes sterile.

CONCLUSION

Taurolidine is expected to be a potential agent for treatment of S. epidermidis endophthalmitis.

Treatment of glioblastoma with intravenous taurolidine. First clinical experience

BACKGROUND

Despite progress in diagnosis and therapy, the prognosis of patients with glioblastoma remains poor. Recently it has been found that the antibacterial agent taurolidine has a direct and selective antineoplastic effect on brain tumor cells by the induction of programmed cell death. This paper reports on intravenous taurolidine treatment in two patients with a progressive glioblastoma despite conventional therapy.

PATIENTS AND METHODS

Two male patients with histopathologically diagnosed glioblastoma were included. The tumors were progressive despite conventional therapy. Intravenous taurolidine treatment was initiated.

RESULTS

The neurological condition and quality of life improved in both patients such that they could be discharged for further outpatient treatment. Follow-up demonstrated partial remission of the tumor in both patients. However, both patients died about 4 months following the start of taurolidine treatment, from pneumonia and acute thrombembolism, respectively.

CONCLUSION

Both patients achieved a transient, marked improvement in quality of life and partial tumor remission. There was a clear response to the taurolidine treatment.

The influence of adhesion prophylactic substances and taurolidine/heparin on local recurrence and intraperitoneal tumor growth after laparoscopic-assisted bowel resection of colon carcinoma in a rat model

BACKGROUND

The goal of the study was to investigate the influence of adhesion prophylactic substances (Interceed/lntergel) as well as taurolidine/heparin on intraperitoneal tumor growth and the local recurrence rate after laparoscopic cecum resection in a rat tumor model.

METHODS

Sixty BDIX rats were randomized in three therapy groups and one control group. A laparoscopic-assisted cecum resection was performed via three-trocar method after intraperitoneal tumor cell application (10,000 cells) of a colon carcinoma cell line (DHD/K1/TRb) in all animals. According to the randomization, the cecum suture and a 1 x 1-cm peritoneal defect were either covered with Intergel/Interceed or 1 ml of 0.5% taurolidine 10 IU heparin. The control group underwent instillation of 1 ml 0.9% NaCl solution. After 4 weeks the animals were euthanized and intraperitoneal tumor growth, local recurrence rate, and the number of intraperitoneal adhesions were determined.

RESULTS

The local recurrence rate was not significantly affected by any of the substances. Nevertheless, taurolidine/heparin significantly reduced the total number and weight of intraperitoneal metastases. The formation of adhesions was not significantly influenced by adhesion prophylaxis substances or by taurolidine/heparin.

CONCLUSIONS

Taurolidine/heparin led to a significant reduction of intraperitoneal tumor growth after intraperitoneal application, whereas local tumor recurrence was not significantly influenced. This might be due to the number of injected tumor cells in this cell suspension model. Interceed and Intergel did not reduce intraperitoneal tumor growth. Furthermore, adhesion formation was not reduced by any of the substances.

Prophylaxis against dialysis catheter-related bacteremia with a novel antimicrobial lock solution

Catheter-related bacteremia, a frequent complication in patients who are undergoing hemodialysis, may be prevented by eradication of the catheter biofilm. Catheter lock solution (CLS) is an investigational preparation containing taurolidine, a biocompatible antimicrobial agent, and citrate, an anticoagulant agent. CLS was instilled into the catheter lumens after each dialysis session for 20 catheter-dependent hemodialysis patients. Catheter outcomes were compared with those observed in 30 concurrent control patients whose catheters were instilled with heparin. Bacteremia-free survival at 90 days was higher among patients who received CLS than among control patients who received heparin (94% vs. 47%; P<.001). Unassisted catheter patency (without tissue plasminogen activator instillation) was lower among patients who received CLS than among control patients (32% vs. 76%; P<.001). CLS dramatically reduces the frequency of catheter-related bacteremia among patients undergoing hemodialysis, although there is an increased requirement for thrombolytic interventions to maintain catheter patency.

Novel therapies for sepsis: antiendotoxin therapies

Severe sepsis and septic shock is a common problem encountered in the critical care unit with an estimated incidence in the US of 750,000 cases/year and a mortality rate of 30-50%. Sepsis involves a complex interaction between bacterial factors and the host immune system producing a systemic inflammatory state that may progress to multiple organ failure and death. Endotoxin (a lipopolysaccharide) released from Gram-negative bacteria has been implicated as a potent, prototypical stimulus of the immune response to bacterial infection. Current antiendotoxin strategies utilise various approaches ranging from the prevention of binding to endotoxin receptors with antibodies (monoclonal or polyclonal) against endotoxin or endotoxin receptor/carrier molecules (antiCD14 or antilipopolysaccharide-binding protein antibodies), enhancing clearance or neutralisation (haemoperfusion, lipoproteins, lipopolysaccharide-neutralising proteins) or impairing cellular signalling (lipid A analogues, tyrosine kinase inhibitors). In the future, innovative therapies involving Toll-like receptors and their downstream signalling elements will be developed. This review discusses current knowledge regarding endotoxin signalling, antiendotoxin therapies currently under development, and future areas for research.

Granulocyte colony-stimulating factor but not peritoneal lavage increases survival rate after experimental abdominal contamination and infection

BACKGROUND

The value of peritoneal lavage for intra-abdominal contamination and infection has never been proven scientifically. In contrast, the stimulation of host defence mechanisms with cytokines such as granulocyte colony-stimulating factor (G-CSF) has appeared promising in recent clinical trials.

METHODS

Clinic modelling randomized trials (CMRTs), which model the complexity of the clinical reality, were used in rats in which peritoneal contamination and infection (PCI) was produced with human stool bacteria. The following groups were compared: trial 1, intraoperative peritoneal lavage with saline versus taurolin (18 rats per group); trial 2, no lavage versus saline lavage versus saline lavage plus subcutaneous administration of G-CSF (18 rats per group); trial 3, lavage with saline versus no lavage (30 rats per group). The primary endpoint was mortality at 120 h. Secondary endpoints were the phagocytic activity of granulocytes, and systemic and peritoneal cytokine levels.

RESULTS

In trial 1 lavage with taurolin was not superior to that with saline (five of 18 versus eight of 18 animals survived; P = 0.32). In trial 2, six of 18 animals having no lavage and three of 18 receiving saline lavage survived. The combination of lavage and G-CSF increased the number of animals surviving to 11 of 18 (P < 0.05). Lavage combined with G-CSF stimulated granulocyte phagocytic activity (P < 0.01) and reduced the levels of interleukin (IL) 6 (P < 0.01) and tumour necrosis factor alpha (P < 0.05) in peritoneal fluid, as well as plasma levels of IL-6 (P < 0.05) and IL-10 (P < 0.01). In trial 3, survival was not significantly different in animals having lavage (14 of 30) and no lavage (19 of 30) (P = 0.14).

CONCLUSION

In these CMRTs of intra-abdominal contamination and infection, peritoneal lavage was not beneficial, but when lavage was combined with subcutaneous administration of G-CSF mortality was reduced and the local and systemic cytokine response was downgraded. Results from these CMRTs were used directly to define the trial conditions of a randomized clinical trial with G-CSF. Peritoneal lavage is not recommended.

Effects of taurolidine and octreotide on port site and liver metastasis after laparoscopy in an animal model of pancreatic cancer

Port site metastasis is a dreadful event following laparoscopy; however, the exact pathomechanism is still unknown. In order to prevent trocar metastasis we determined the effects of intraperitoneal lavage with either taurolidine or octreotide on port site and liver metastasis after laparoscopy in a chemically induced, solid pancreatic adenocarcinoma. Pancreatic adenocarcinoma was induced in 60 Syrian hamsters by weekly injection of 10 mg/kg body weight N-nitrosobis-2-oxopropylamine s.c. for 10 weeks. Six weeks later, a laparoscopic pancreatic biopsy was performed by the use of a pneumoperitoneum with carbon dioxide (12 mm Hg), followed by an abdominal irrigation with 5 ml normal saline (group 1, n = 20), 5 ml 0.5% taurolidine (group 2, n = 20) or 5 ml octreotide (20 mg/ml) (group 3, n = 20). After 8 weeks, all hamsters were sacrificed and histopathologically examined. There was only one macroscopic visible primary tumor in the taurolidine group (5.9%), compared to 42.1% in the saline group and 62.5% in the octreotide group (P < 0.05). The size of carcinomas was smaller in the saline group than after octreotide irrigation (median 6, range 2-25 vs. median 70, range 40-160 mm2, P < 0.05). The number of liver metastases per animal was increased after saline irrigation (median 4, range 2-6), compared to taurolidine (median 2, range 1-3) or octreotide (median 2.5, range 2-4) (P < 0.05). Port site metastases were found in 36.8% after saline, in 37.5% after octreotide and in 0% after taurolidine irrigation (P < 0.05). Thus port site metastasis was effectively prevented by taurolidine irrigation after staging-laparoscopy in pancreatic cancer.

Influence of intraperitoneal and systemic application of taurolidine and taurolidine/heparin during laparoscopy on intraperitoneal and subcutaneous tumour growth in rats

BACKGROUND

Recent clinical and experimental studies investigated the problem and possible pathomechanisms of portsite metastases after laparoscopic resection of malignant tumours. A generally accepted approach to prevent these tumour implantations does not exist so far.

METHODS

After subcutaneous and intraperitoneal injection of 10(4) cells of colon adenocarcinoma (DHD/K12/TRb) the influences of either taurolidine or taurolidine/heparin on intraperitoneal and subcutaneous tumour growth were investigated in 105 rats undergoing laparoscopy with carbon dioxide. The animals were then randomised into seven groups. A pneumoperitoneum was established using carbon dioxide for 30 min (8 mmHg). Three incisions were used: median for the insufflation needle, and a right and left approach in the lower abdomen for trocars. To investigate the intraperitoneal (local) influence of either taurolidine and heparin on tumour growth the substances were instilled intraperitoneally. Systemic effects were expected when the substances were applied intravenously (iv). Synergistic influences were tested when both application forms were combined. The number and the weight of tumours as well as the incidence of abdominal wall and port-site metastases were determined four weeks after intervention. Blood was taken to evaluate the influences of taurolidine and heparin on systemic immunologic reactions: seven days before laparoscopy. two hours, two days. seven days, and four weeks after operation, and the peripheral lymphocytes were determined.

RESULTS

Intraperitoneal (ip) tumour weight in rats receiving taurolidine (median 7 mg) and taurolidine/heparin (0 mg) intraperitoneally was significantly reduced when compared to the control group (52 mg) (P = 0.001). There was no difference of subcutaneus tumour growth among the groups (P = 0.4). Trocar recurrences were decreased when taurolidine was applied ip (3115). ipiv (4/15), and ip in combination with heparin (4/15) in comparison to the control group (10/15). Immediately after intervention treated and untreated groups showed a peripheral lymphopenia.

CONCLUSIONS

The intraperitoneal therapy with taurolidine and the combination with heparin inhibits the intraperitoneal tumour growth and trocar recurrences. Neither the intraperitoneal nor the systemic application or the combination of taurolidine and heparin did reduce the subcutaneous tumour growth. The intervention caused a lymphopenia which was compensated on day two.

Differential alteration of cardiotonic effects of EMD 57033 and beta-adrenoceptor agonists in volume-overload rabbit ventricular myocytes

BACKGROUND

We investigated the effects of EMD 57033, a prototype Ca2+ sensitizer, and beta-adrenoceptor agonists in ventricular myocytes isolated from the volume-overload (V-O) heart failure model of the rabbit.

METHODS AND RESULTS

V-O cardiac hypertrophy was induced in rabbits by the formation of an arterio-venous shunt between the carotid artery and jugular vein 12 to 15 weeks after the operation. Ventricular myocytes were enzymically isolated from normal and V-O rabbit hearts. The myocyte was loaded with a fluorescence Ca2+ dye, indo-1, and Ca2+ transients, and cell lengths were measured simultaneously. V-O myocytes were significantly larger than control myocytes. Duration of Ca2+ transients and cell shortening was significantly longer in the V-O myocytes than in control myocytes. Effects of cardiotonic interventions, including EMD 57033, isoproterenol, and dobutamine, on Ca2+ transients and cell shortening in V-O myocytes were compared with those in control rabbit myocytes. Isoproterenol and dobutamine increased the systolic cell shortening and peak Ca2+ transients and abbreviated the duration of cell shortening and Ca2+ transients. These responses were markedly attenuated in V-O myocytes. By contrast, the response of cell shortening to EMD 57033 was unaltered, and the Ca2+ sensitizing effect of EMD 57033 was rather enhanced in V-O myocytes.

CONCLUSION

Our results indicate that the effectiveness of Ca2+ sensitizers is maintained in the V-O rabbit hypertrophy and heart failure model in contrast to the blunted response to beta-adrenoceptor agonists, which provides an insight on therapeutic strategy with Ca2+ sensitizers for the treatment of contractile dysfunction in congestive heart failure.

Taurolidine inhibits tumor cell growth in vitro and in vivo

BACKGROUND

Taurolidine, a derivative of the amino acid taurine, exhibits antiendotoxin, antibacterial, and antiadherence activity. We hypothesized that Taurolidine may inhibit tumor cell growth, both in an in vitro and in vivo setting. Our aim was to examine the effect of Taurolidine on the growth of a rat metastatic colorectal tumor cell line (DHD/K12/TRb) in vitro and in vivo.

METHODS

In the in vitro experiments, DHD/K12/TRb cells were incubated with 5, 10, 15, 25, microg/ml of Taurolidine. Cells incubated in culture medium alone were used as controls. Cell proliferation, cell viability, cell death, and cell apoptosis were measured using commercially available techniques. In the in vivo experiment, BD IX rats were randomized into two groups (n = 10/group). Group A (control) underwent laparotomy and instillation of DHD/K12/TRb tumor cells intraperitoneally followed by phosphate buffered saline (PBS). Group B received Taurolidine (100 mg/kg) instead of PBS. Animals were killed after 24 days and tumor burden assessed by counting the number of tumor nodules in the peritoneal cavity.

RESULTS

Incubation of the tumor cells with Taurolidine resulted in a 4-fold decrease in proliferation rates (25+/-4% vs. 100+/-28% for controls) and a 4-fold increase in cell necrosis as demonstrated by the increase in LDH release (403+/-28% vs. 100+/-26% for controls), at a Taurolidine concentration of 25 microg/ml. A dose-dependent decrease in cell viability was also observed. In the in vivo study, local Taurolidine administration resulted in significant decreases in tumor burden (3+/-1 nodules in Group B animals vs. 649+/-101 nodules in Group A animals).

CONCLUSIONS

Taurolidine inhibits the growth of a rat metastatic colorectal tumor cell line in vitro and in vivo and thus may have potential in the prevention of peritoneal metastases.

New therapeutic strategies to avoid intra- and extraperitoneal metastases during laparoscopy: results of a tumor model in the rat

BACKGROUND

Therapeutic strategies to prevent port site recurrences in laparoscopy surgery of malignancies have not been investigated until now.

METHODS

The effects of taurolidine, heparin, and povidone iodine on the growth of rat and human colon adenocarcinoma as well as gallbladder carcinoma were investigated in vitro. Furthermore, cytokine release of growth-stimulating IL-1beta by peritoneal macrophages was measured after incubation with carbon dioxide and additional incubation with the different agents. In the third experiment, prevention of intra- and extraperitoneal metastases by intraperitoneal instillation of the different agents during laparoscopy was investigated in a colon carcinoma model in the rat. Tumor cells were administered intraperitoneally in 100 rats, and pneumoperitoneum (8 mm Hg) was established over 30 min with carbon dioxide. Rats received either tumor cells, cells + heparin, cells + povidone iodine, cells + taurolidine, or cells + taurolidine + heparin.

RESULTS

In vitro, tumor cell growth decreased after incubation with taurolidine, taurolidine/heparin, and povidone iodine. Cytokine release was stimulated by incubation with carbon dioxide and could only be suppressed by incubation with taurolidine in vitro. In vivo, intraperitoneal tumor weight was lower in rats receiving heparin (251 +/- 153 mg) and povidone iodine (134 +/- 117 mg) compared to the control group (541 +/- 291 mg), but even less when taurolidine (79 +/- 82 mg) or taurolidine/heparin (18.3 +/- 30 mg) were instilled.

CONCLUSION

Heparin slightly inhibits intraperitoneal tumor growth in vivo, while povidone iodine and taurolidine cause a significant decrease in tumor cell growth in vitro as well as intraperitoneal tumor growth in vivo. Cytokine release of peritoneal macrophages is only suppressed by taurolidine. Total tumor take and trocar metastases are only suppressed by taurolidine and taurolidine/heparin.

Experimental studies on myocardial stretch and ventricular arrhythmia in hypertrophied and non-hypertrophied hearts

Hypertension affects about 5% of western populations and in the majority of cases it is of unknown aetiology. It exposes the heart to greater levels of myocardial stretch as a result of increased systolic pressure and peripheral resistance. Under certain circumstances myocardial stretch may trigger arrhythmias but the mechanisms and clinical importance of this phenomenon are unclear. This article outlines the risks of sudden cardiac death conferred by hypertension and left ventricular hypertrophy, presents the results of experiments using an animal model of myocardial stretch and discusses some possible mechanisms underlying stretch-induced arrhythmias which may be important in hypertensive patients.

Local treatment of generalised peritonitis in rats; effects on bacteria, endotoxin and mortality

OBJECTIVE

To assess the effect of debridement, intraoperative lavage with saline, and additional instillation of taurolidine or imipenem/cilastatin in rats with faecal peritonitis.

DESIGN

Laboratory study.

SETTING

University hospital, The Netherlands.

MATERIAL

60 male Wistar rats.

INTERVENTIONS

Rats were given an intraperitoneal injection of a faecal suspension containing Escherichia coli and Bacteroides fragilis. Six groups of 10: sham operation, debridement, debridement with saline lavage, debridement with saline lavage with intraperitoneal instillation of saline or taurolidine, or imipenem/cilastatin, were studied.

MAIN OUTCOME MEASURES

Bacterial growth and endotoxin concentration in abdominal exudate and plasma, abscess formation, and mortality.

RESULTS

Debridement temporarily reduced bacterial growth and the concentration of endotoxin in abdominal exudate, and delayed mortality. Lavage with saline further reduced bacterial growth and the endotoxin concentration. It also reduced the plasma endotoxin concentration, and mortality. Additional instillation of taurolidine did not reduce bacterial growth, but did initially reduce the endotoxin concentration in abdominal exudate and plasma. Instillation of imipenem/cilastatin, after debridement and lavage, significantly reduced all variables measured.

CONCLUSION

In rats with faecal peritonitis, debridement, lavage with saline, and additional instillation of imipenem/cilastatin, all have cumulatively reducing effect on bacterial growth, endotoxin concentrations, abscess formation, and mortality. Instillation of taurolidine reduces only the amount of endotoxin.

Antioxidant status in experimental peritonitis: effects of alpha tocopherol and taurolin

The role of oxidative stress and antioxidant defences in inflammation-induced organ injury is not clearly understood. We determined the effects of Escherichia coli (E. coli) peritonitis in rats on peritoneum lipid peroxidation and antioxidant defences. Tissue malondialdehyde (MDA) levels were measured to determine the free radical-induced lipid peroxidation in peritonitis. Tissue glutathione (GSH) levels, and activities of GSH-peroxidase, GSH-reductase and superoxide dismutase were examined to show antioxidant status. We also examined the effects of alpha-tocopherol (20 mg kg-1 body weight) as antioxidant and taurolin (200 mg kg-1 body weight) as chemotherapeutic agents on the oxidant stress and antioxidant defence. The treatment agents and E. coli were administrated intraperitoneally. Animals were killed at 2 h after the onset symptoms and then the peritoneum were obtained. Untreated rats with peritonitis had significantly higher MDA levels and significantly lower antioxidant activity than that of the control animals. Treatment of alpha-tocopherol and taurolin decreased the antioxidant activity and improved the antioxidant status. Pretreatment with alpha-tocopherol for 3 days prior to the induction of peritonitis (IP) and administration of taurolin at the time of the IP were more effective than treatment with alpha-tocopherol at the time of the IP and pretreatment of taurolin, respectively. These results are consistent with the idea that an oxidant/antioxidant imbalance is involved in animal peritonitis. Uses of alpha-tocopherol and taurolin in peritonitis were effective in decreasing the oxidative stress of tissue during peritonitis.

[The technology for manufacturing antiparasitic preparations. 9. The new preparation tizanox and an evaluation of its anti-Hymenolepis activity]

The paper describes a procedure for manufacturing the new anthelminthic Tizanox. It shows it necessary to administer a larger dose of the drug than that of azinox (praziquantel) to treat experimental hymenolepiasis. However, the lower toxicity of Tizanox enhances its chemotherapeutical index.