Efficacy and safety of current drug therapies for invasive aspergillosis.

Invasive aspergillosis (IA) is a potentially lethal infection that affects mostly immunocompromised patients. The therapeutic goals are to restore leucocyte function and to reduce the fungal burden by effective antifungal agents and, contingently, by surgery. Several drugs for the treatment of IA are currently licensed. The longest known among them is amphotericin B (AmB). In well-performed clinical trials, approximately 30-50% of participants treated with AmB showed complete or partial response. However, this drug is associated with considerable acute and chronic toxicity which was somewhat mitigated by the development of lipid-based formulations. In contrast, voriconazole (VRC) is better tolerated, penetrates well into the central nervous system and may be given intravenously and orally in a sequential manner. The overall rates of favourable response to VRC were similar to that for AmB. Most notably, double-digit rates of complete remission were observed in studies including extraordinarily high proportions of patients with proven IA and specific risk factors. Disadvantages of VRC include the genetically determined interindividual variability of pharmacokinetics and the potential for drug-drug interactions that may require therapeutic drug monitoring. The recently introduced caspofungin (CPF) offers an excellent safety profile, but underperformed in terms of efficacy against mold infections. Other antifungals such as itraconazole and posaconazole are presently recommended as second-line option for the therapy or prophylaxis of (non-)IA. The value of micafungin and anidulafungin remains to be investigated in randomized clinical trials. In guidelines released by relevant medical societies, VRC is recommended as the first choice in the treatment of IA. AmB, preferably given as a liposomal preparation, or combinatory antifungal regimens combining VRC or liposomal AmB with CPF are stated as alternative options.

Coagulation factor VIII levels are associated with long-term survival - interactions with gender in a large hospital-based cohort.

INTRODUCTION: Elevated coagulation factor VIII activity has been associated with increased risk for both venous and arterial thrombosis. The current study evaluated the influence of Factor VIII levels and interactions with gender on all cause mortality in a large Austrian cohort. PATIENTS AND METHODS: During 1991 and 2003, 11203 individuals, first ever request for laboratory analyses of FVIII: C, age > or =18 years, were included in this study. The median observation period was 5 years covering a total of 46000 person-years. The death rate was 17.1%. RESULTS: Compared to individuals within the reference category (FVIII: C <94%) hazard ratios gradually increased from 1.4 (95% CI: 1.1-1.8) in the 152-170% category (5th decile) to finally 4.4 (95% CI: 3.5-5.5) in the >313% category (highest decile, all p < 0.05). The association between FVIII: C levels and mortality remained essentially unchanged when considering non-cancer mortality, all cause vascular mortality or mortality due to ischemic heart disease. Compared to males females with elevated FVIII: C had a worse outcome resulting in higher hazard ratios reaching 6.8 (95% CI: 4.6-9.9) within the highest decile compared to males (HR: 3.4 (95% CI: 2.6-4.5)). CONCLUSIONS: In our large patient cohort we might be able to demonstrate for the first time that FVIII: C plasma activity is strongly associated with all cause mortality. Additionally, FVIII: C appears to interact with gender. Especially in women FVIII: C might help identifying high-risk cohorts, which might benefit from individualized prevention strategies.

Tigecycline has no effect on cytokine release in an ex vivo endotoxin model of human whole blood.

In previous studies, tetracyclines have been shown to decrease the release of cytokines in experimental settings of endotoxaemia. Tigecycline is the first member of the closely related glycylglycines and, due to its broad antimicrobial spectrum, it is considered useful in the treatment of sepsis. We therefore tested its ability to influence the concentrations of the proinflammatory cytokines interleukin (IL)-1beta, tumour necrosis factor-alpha (TNFalpha) and IL-6 in an established ex vivo model of human endotoxaemia. Whole blood from ten healthy volunteers was incubated with either saline (negative control), tigecycline (1 microg/mL [therapeutic concentration] or 100 microg/mL [supratherapeutic concentration]), lipopolysaccharide (LPS; 50 pg/mL, control) or a combination of tigecycline plus LPS (test group). Concentrations of IL-1beta, TNFalpha and IL-6 in the supernatant were measured using commercially available enzyme-linked immunosorbent assay (ELISA) kits. As expected, incubation with LPS significantly increased the cytokine concentrations in whole blood compared with baseline (P<0.05). The combination of tigecycline plus LPS did not exert any significant effect on the concentrations of IL-1beta, IL-6 and TNFalpha after 2h and 4h of incubation compared with LPS alone. These results indicate that proinflammatory cytokines remained unaffected by tigecycline in an established ex vivo model of systemic inflammatory response.

Orally administered rapamycin, dacarbazine or both for treatment of human melanoma evaluated in severe combined immunodeficiency mice.

OBJECTIVE: In this experimental study, the antineoplastic potential of orally administered rapamycin in human melanoma was evaluated and compared with dacarbazine (DTIC) as well as with the antineoplastic effect of the combination of both drugs. METHODS: The substances were tested using 2 human melanoma cell lines, 518A2, which is highly susceptible to DTIC, and 607B, which is moderately susceptible. A human melanoma severe combined immunodeficiency mouse xenotransplantation model was used. After development of palpable tumors, mice received oral rapamycin or saline over 18 days. Additionally, from treatment day 4 to 8, mice were randomly chosen to receive either DTIC or saline treatment. RESULTS: The oral rapamycin treatment (1.5, 7.5, 15 and 30 mg/kg body weight) had an antineoplastic effect, ranging from 35 to 78% tumor weight reduction compared with the saline group. In DTIC less sensitive 607B tumors, rapamycin treatment (15 and 30 mg/kg body weight) was superior to DTIC treatment (p < 0.05). DTIC monotreatment reduced tumor weight in 518A2 tumors by 85% on average, whereas in 607B xenografts, no significant tumor weight reduction was observed compared with the saline group (p > 0.05). The combination of rapamycin and DTIC was not superior to rapamycin monotreatment in any cell line. CONCLUSION: These data indicate that oral rapamycin exerts a relevant antineoplastic effect on human melanoma cells. This effect appeared to be more pronounced in DTIC less sensitive melanoma xenografts.

S-ibuprofen effectively inhibits thromboxane B2 levels and platelet function in an experimental model of lipopolysaccharide-stimulated and non-stimulated whole blood.

OBJECTIVE: The present study aimed at testing the effect of S- and R-ibuprofen on thromboxane B(2) (TXB(2)), collagen-epinephrine closure time (CEPI-CT) and collagen-adenosine 5'-diphosphate closure time (CADP-CT) in lipopolysaccharide (LPS)-stimulated and non-stimulated human whole blood. MATERIALS AND METHODS: Whole blood was incubated with S- or R-ibuprofen with and without prior stimulation with LPS. To verify ibuprofen's potential effects on TXB(2), varying ratios of concentrations of S- and R-ibuprofen ranging from 0 to 100% were used. TXB(2) levels were measured by ELISA. The effects of S- and R-ibuprofen enantiomers on platelet aggregability were tested utilizing a PFA-100 apparatus. RESULTS: In non-stimulated and LPS-stimulated whole blood, S-ibuprofen markedly decreased TXB(2) levels at concentrations ranging from 10 to 200 microg/ml. R-ibuprofen showed its inhibiting effect at concentrations >100 microg/ml. In inflammatory and non-inflammatory conditions, CEPI-CT was prolonged at concentrations of 12.5 and 75 microg/ml for S-ibuprofen and at a concentration of 150 microg/ml of combined R- and S-ibuprofen. S-ibuprofen was significantly more effective than R-ibuprofen (p < 0.05). The combined use of S- and R-ibuprofen did not additively or synergistically prolong CEPI-CTs. CADP-CTs remained unaffected by both enantiomers. CONCLUSIONS: S-ibuprofen was more effective than the R-ibuprofen enantiomer in inhibiting TXB(2) plasma levels and aggregability of thrombocytes in non-inflammatory and inflammatory conditions.

Pharmacokinetics of linezolid in bone tissue investigated by in vivo microdialysis.

Pharmacokinetics of unbound anti-infectives in bone is difficult to characterize. The aim of this study was to assess the feasibility of the microdialysis technique to cancellous bone for single dose pharmacokinetic investigations of the anti-infective linezolid. Serial bone biopsies (left tibia) and microdialysate samples (right tibia: 2 catheters) as well as plasma and bone marrow samples were obtained from 10 pigs. The concentrations of linezolid reached bacteriostatic levels in plasma, bone marrow, bone biopsies and microdialysates. With the use of microdialysis we here present the first results for unbound linezolid bone penetration. Unbound linezolid concentrations in bone obtained by microdialysis were lower than might have been expected from previous bone biopsy studies. To achieve effective concentrations (24 h) for susceptible organisms the chosen dose of linezolid might not be sufficient.

C-reactive protein and all-cause mortality in a large hospital-based cohort.

BACKGROUND: C-reactive protein (CRP), an acute-phase protein, is a sensitive systemic marker of inflammation and acute-phase reactions. Testing CRP concentrations at hospital admission may provide information about disease risk and overall survival. METHODS: All first-ever transmittals to the department of medical and chemical laboratory diagnostics for determination of low-sensitivity CRP (n = 274 515, 44.5% male, median age 51 years) between January 1991 and July 2003 were included [median follow-up time: 4.4 years (interquartile range, 2.3-7.4 years)]. The primary endpoint was all-cause mortality. Multivariate Cox regression adjusted for sex and age was applied for analysis. RESULTS: Compared to individuals within the reference category (CRP <5 mg/L), hazard ratios (HR) for all-cause mortality increased from 1.4 (5-10 mg/L category) to 3.3 in the highest category (>80 mg/L, all P <0.001). CRP was associated with various causes of death. The relation of CRP to cancer death was stronger than to vascular death. Younger patients with increased CRP had relatively far worse outcome than older patients (maximal HR: < or =30 years: 6.7 vs >60 years: 1.7-3.7). Interestingly, both short- and long-term mortality were associated with increasing CRP concentrations (>80 mg/L: HR 22.8 vs 1.4). CONCLUSION: Measurement of low-sensitivity CRP at hospital admission allowed for the identification of patients at increased risk of unfavorable outcome. Our findings indicate that close attention should be paid to hospitalized patients with high CRP not only because of very substantial short-term risk, but also long-term excess risk, the basis for which needs to be determined.

Comparison of a treatment strategy combining CCI-779 plus DTIC versus DTIC monotreatment in human melanoma in SCID mice.

This study compares the antineoplastic potential of a novel treatment strategy combining cell cycle inhibitor-779 (CCI-779) plus dacarbazine (DTIC) versus DTIC monotreatment, the current chemotherapeutic mainstay in combating metastatic melanoma. A controlled four-group parallel study design comprising 24-40 mice per tumor cell line was used in a severe combined immunodeficiency (SCID)-mouse xenotransplantation model. SCID mice were injected with 518A2, Mel-JUSO, or 607B human melanoma cells. After they developed tumors, mice received daily CCI-779 or solvent over 14 days. From treatment day 4-8 mice were additionally injected with DTIC or saline. Treatment with CCI-779 plus DTIC was superior to single agent DTIC in two out of three cell lines (P<0.05). The tumor weight reduction was 44+/-17 and 61+/-6% compared with DTIC monotreatment in Mel-JUSO and 607B melanomas, respectively (P<0.05). In contrast, in 518A2 xenotransplants, CCI-779 plus DTIC treatment was as effective as DTIC monotreatment. CCI-779 monotherapy exerted no statistically significant antitumor effect. Collectively, these data indicate that CCI-779 has the potential to increase the chemotherapeutic efficacy, as the combination of CCI-779 plus DTIC proved to be more efficacious compared to DTIC monotherapy in two out of three melanoma cell lines in vivo.

Immunomodulatory effects of fosfomycin in experimental human endotoxemia.

To evaluate the effect of fosfomycin on proinflammatory cytokines, a bolus of 2 ng of bacterial lipopolysaccharide/kg of body weight was injected intravenously into healthy volunteers. After 2 h, subjects received 8 g of fosfomycin or placebo in a randomized crossover study design. The resulting concentrations of tumor necrosis factor alpha, interleukin-1beta (IL-1beta), and IL-6 expressed as protein and mRNA levels were almost identical with and without fosfomycin.

A pilot study testing whether concentrations of levofloxacin in interstitial space fluid of soft tissues may serve as a surrogate for predicting its pharmacokinetics in lung.

Recent observations indicate that pharmacokinetics of beta-lactam antibiotics in the lung can be predicted by the use of concentration versus time profiles in peripheral soft tissues. If this observation is transferred to other classes of antimicrobials, measurement of antimicrobial concentrations in peripheral tissues would enable prediction of the pharmacokinetics of antimicrobials at the site of the respiratory tract infection. We set out to test the hypothesis that concentrations of the fluoroquinolone levofloxacin in the respiratory tract can be predicted on the basis of knowledge of its pharmacokinetics in peripheral soft tissues. After administration of a single intravenous dose of 500mg of levofloxacin, microdialysis was used to describe the concentration versus time profiles of levofloxacin in the interstitial space fluid of lung tissue of patients (n=5) undergoing elective lung surgery. These data were compared with the concentration versus time courses in the interstitial space fluid of skeletal muscle and subcutaneous adipose tissue of healthy volunteers (n=7). The median AUC(0-infinity) of free levofloxacin in lung (2267mg x min/L, 1980-2355) was about 2-fold and 1.5-fold lower compared with skeletal muscle (4381mg x min/L, range 1720-8195) and adipose tissue (3492mg x min/L, range 1323-6420) of healthy controls, respectively. Concentrations in the interstitial space fluid of the lung were descriptively lower compared with corresponding concentrations in peripheral soft tissues. This is in contrast to previous observations made for the class of beta-lactam antibiotics, and indicates that pharmacokinetics of levofloxacin derived from soft tissues may not be used uncritically for prediction of levofloxacin concentrations in the interstitium of the lung.

Immunomodulatory effects of fosfomycin in an endotoxin model in human blood.

OBJECTIVES: Although a wide range of therapeutic strategies have been developed to improve the outcome of severe sepsis, a convincing reduction in mortality is lacking. Recently, increasing attention has been paid to immunomodulatory effects of antimicrobials. This study set out to explore the immunomodulatory effects of fosfomycin, a broad-spectrum antibiotic frequently used in septic patients, at the protein and molecular levels in vitro. METHODS: Whole blood from 11 healthy volunteers was incubated with 50 pg/mL endotoxin and 100 microg/mL fosfomycin or physiological sodium chloride for 4 h. Real-time RT-PCR was performed for various pro- and anti-inflammatory cytokines. Concentrations of tumour necrosis factor (TNF)-alpha and interleukin (IL)-6 in the supernatant were measured using a commercially available ELISA. RESULTS: Incubation of human leucocytes with endotoxin increased messenger RNA (mRNA) levels of cytokines several thousand fold compared with baseline. The addition of fosfomycin significantly inhibited mRNA levels of pro-inflammatory cytokines such as IL-1-alpha, IL-6 and TNF-alpha after 2 h (P < 0.01), while no significant reduction was observed for the anti-inflammatory cytokines IL-4, IL-10 and IL-13 (P = 0.26). At the protein level, the concentrations of IL-6 and TNF-alpha increased approximately 3000- and 600-fold after 4 h of incubation with lipopolysaccharide as compared with baseline, respectively. Addition of fosfomycin significantly reduced cytokine levels by 56% and 73% for IL-6 and TNF-alpha, respectively. CONCLUSIONS: Fosfomycin extensively decreased mRNA levels and release of pro-inflammatory cytokines in human blood. The broad antimicrobial coverage of fosfomycin and its immunosuppressive effects could be clinically useful in patients with sepsis.

Lung microdialysis--a powerful tool for the determination of exogenous and endogenous compounds in the lower respiratory tract (mini-review).

In vivo measurement of concentrations of drugs and endogenous substances at the site of action has become a primary focus of research. In this context the minimal invasive microdialysis (MD) technique has been increasingly employed for the determination of pharmacokinetics in lung. Although lung MD is frequently employed to investigate various drugs and endogenous substances, the majority of lung MD studies were performed to determine the pharmacokinetic profile of antimicrobials that can be related to the importance of respiratory tract infections. For the lower respiratory tract various methods, such as surgical collection of whole lung tissue and bonchoalveolar lavage (BAL), are currently available for the determination of pharmacokinetics of antimicrobials. Head-to-head comparison of pharmacokinetics of antibiotics in lung revealed high differences between MD and conventional methods. MD might be regarded as a more advantageous approach because of its higher anatomical resolution and the ability to obtain dynamic time-vs-concentration profiles within one subject. However, due to ethical objections lung MD is limited to animals or patients undergoing elective thoracic surgery. From these studies it was speculated that the concentrations in healthy lung tissue may be predicted reasonably by the measurement of concentrations in skeletal muscle tissue. However, until now this was only demonstrated for beta-lactam antibiotics and needs to be confirmed for other classes of antimicrobials. In conclusion, the present review shows that MD is a promising method for the determination of antimicrobials in the lung, but might also be applicable for measuring a wide range of other drugs and for the investigation of metabolism in the lower respiratory tract.

Citrate kinetics in patients receiving long-term hemodialysis therapy.

BACKGROUND: Regional anticoagulation using sodium citrate is used increasingly in hemodialysis patients at high risk for bleeding. However, citrate metabolism has never been evaluated systematically in hemodialysis patients, and it remains to be shown that citrate is cleared adequately in the presence of renal dysfunction. This study compares the pharmacokinetics of citrate in hemodialysis patients with minimal residual function with that in patients with normal renal function. METHODS: Long-term hemodialysis patients (n = 7) and patients without renal failure (n = 11) were investigated during routine immunoadsorption treatment by using a standardized citrate infusion protocol. Serial analysis of blood samples was performed before, during, and up to 120 minutes after citrate infusion (0.33 mmol/kg/h). Citrate plasma concentrations were measured colorimetrically. In addition, ionized calcium, pH, and bicarbonate were measured by using a blood gas analyzer. RESULTS: Basal (0.09 +/- 0.03 versus 0.12 +/- 0.03 mmol/L; P = not significant) and peak citrate concentrations were similar in both groups (1.24 +/- 0.42 versus 1.19 +/- 0.33 mmol/L; P = not significant). Citrate clearance was similar in patients with renal failure (0.31 +/- 0.06 L/min) and controls (0.35 +/- 0.11 L/min; P = 0.47). Effects on pH were minimal and did not differ between groups. No patient developed complications from citrate infusion. CONCLUSION: Compared with controls, citrate clearance and metabolism in long-term hemodialysis patients is not impaired, and no significant acid-base disorder occurred during citrate anticoagulation. From these data, it is tempting to conclude that citrate anticoagulation can be used safely in patients with chronic renal failure on regular hemodialysis therapy.

Safety and potential of drug interactions of caspofungin and voriconazole in multimorbid patients.

Due to their broad antimycotic spectrum and the relatively low rate of side effects, the two antifungals caspofungin and voriconazole are considered as attractive therapeutic alternatives to amphotericin B. However, treatment of severe mycotic infections in patients taking co-medication is associated with the risk of severe adverse drug interactions. The risk of such interactions is increased if voriconazole and, much less pronounced caspofungin, are co-administered with drugs which have an inducing or inhibiting effect on the CYP 450 system, primarily on the isoenzymes CYP2C19, CYP2C9 and CYP3A4. This review provides a comprehensive overview on the potential drug interactions of caspofungin and voriconazole in multimorbid patients.

The interleukin-6 G(-174)C promoter polymorphism does not determine plasma interleukin-6 concentrations in experimental endotoxemia in humans.

BACKGROUND: Interleukin 6 (IL-6) is a pleiotropic cytokine that plays an essential role in the pathogenesis of acute and chronic infections. As the role of the IL-6 G(-174)C polymorphism in determining serum concentrations of IL-6 is controversial, we studied the genotype-specific IL-6 response in a well-standardized model of systemic inflammation. METHODS: A total of 76 healthy young males (age range, 19-35 years) received a single bolus of 2 ng/kg endotoxin [lipopolysaccharide (LPS)] intravenously. Plasma IL-6 was measured by enzyme immunoassay at 0, 2, 6, and 24 h after LPS infusion, and the IL-6 promoter genotype was analyzed by a mutagenic separated PCR assay. RESULTS: IL-6 increased 300-fold 2 h after LPS challenge and returned almost to normal within 24 h. Neither basal IL-6 nor the IL-6 response to LPS was significantly affected by the IL-6 promoter genotype. CONCLUSIONS: The IL-6 G(-174)C promoter polymorphism does not significantly influence basal concentrations of IL-6 or peak IL-6 in human endotoxemia.

Closed-chest microdialysis to measure antibiotic penetration into human lung tissue.

The majority of bacterial lung infections are localized to the interstitial space fluid, which is therefore an important target site for antimicrobial chemotherapy. Direct measurement of interstitial concentrations of antimicrobial agents in human lung tissue would allow for a more informed approach to appropriate dosing of antimicrobial agents, but until now this was beyond technical reach. In this exploratory pharmacokinetic study, we measured the time versus concentration profile of cefpirome after a single intravenous dose administration of 2 g in the lung interstitial fluid by flexible microdialysis catheters, which were implanted during lung surgery for pulmonary tumors in five patients. Cefpirome concentrations in lung interstitial fluid were 66% of corresponding plasma values within the first 240 min, and exceeded minimal inhibitory concentrations of most relevant bacteria. The experimental procedure was well tolerated by the patients and no adverse events were observed. The present study provides evidence for the first time that closed chest microdialysis of the human lung is a feasible and safe method to measure lung concentrations in patients in vivo. The present data also corroborate the use of cefpirome as a valuable agent in the treatment of lung infections with most extracellular bacteria.