Diána Mühl

Dynamic changes of matrix metalloproteinases and their tissue inhibitors in severe sepsis

PURPOSE Little is known about the dynamic changes of matrix metalloproteinases (MMPs) and their inhibitors (TIMPs) in sepsis. Our aim was therefore to investigate the time course of MMPs and their inhibitors in patients experiencing severe sepsis. METHODS Our prospective controlled analysis included 38 patients with severe sepsis. Plasma levels of MMP-2, MMP-9, TIMP-1, and TIMP-2 were measured daily at a 5-day-long period with enzyme-linked immunosorbent assay. Seventeen healthy volunteers were invited as controls. RESULTS MMP-2 showed no difference compared to controls, whereas significantly elevated MMP-9 levels were detected on admission (P < .005). Significantly elevated but declining TIMP-1 levels were measured during the whole trial (P < .002-.004). Except for the second day, TIMP-2 levels were significantly lower than controls (P < .05-.009). MMP2/TIMP-1 ratios were significantly lower in septic patients (P < .03-.006), whereas MMP-2/TIMP-2 ratios were elevated throughout our study (P < .03-.006). MMP-9/TIMP-1 ratios were significantly lower at the first 3 days (P < .05-.008). MMP-9/TIMP-2 was significantly elevated on admission (P < .006). CONCLUSIONS Our research is the first follow-up study dealing with MMPs, TIMPs, and their ratios in severe sepsis. Our results indicate that MMPs and TIMPs may play a crucial role in severe sepsis, especially TIMP-1, MMP-9, and possibly TIMP-2, after an extensive study.

Microparticles and acute renal dysfunction in septic patients

PURPOSE The role of microparticles (MPs) in the pathogenesis of sepsis is not completely elucidated. We aimed to assess changes in the number of MPs during severe sepsis to follow the effect of sepsis-related organ failures, particularly renal impairment, an independent mortality factor of sepsis. MATERIALS AND METHODS Thirty-seven severe septic patients and 20 controls were enrolled. Patient status as well as organ failure-related laboratory markers was followed up to 5 consecutive days. Microparticles (annexin V+ events in MP size gate) of platelet (CD41, CD42a, and PAC1), monocyte (CD14), and myeloid cell line (CD13) origin were measured using flow cytometry. RESULTS Significantly increased total MP and CD41-, CD42a-, and PAC1-positive particle numbers were found in septic patients compared with controls. Actual number of organ dysfunctions on sample collection showed no correlation with MP numbers. Septic patients with renal dysfunction showed an increase in total MP, CD41(+), and CD13(+) particle numbers on admission. Amounts of platelet-derived CD42a(+) particles from patients with sepsis-related renal injury correlated negatively with actual blood urea nitrogen and creatinine concentrations. CONCLUSION The increased numbers of platelet-derived MPs in severe septic patients emphasize the possible contribution of the hemostasis system in the development of sepsis-related renal impairments.

Activated platelet-derived microparticle numbers are elevated in patients with severe fungal (Candida albicans) sepsis

Background The treatment of severe sepsis highly depends on the identification of bacteria or fungi from blood and/or other body materials. Although widely available blood culturing and risk assessment scores are not completely reliable, current guidelines do not recommend the wide empirical use of antifungal medications based on questionable benefit or possible side-effects. We aimed to test whether platelet-derived microparticle (MP) measurements can improve the early detection of the infective agent behind sepsis. Methods Thirty-three consecutive severe septic patients from our university intensive care unit were included in our prospective study. MP number and surface antigen characteristics were followed by flow cytometry on days 1 (admission), 3 and 5. For microbiological identification, various specimens were collected on admission and in case of overall status deterioration. Results On admission, septic patients showed elevated annexin V and constitutive platelet marker (CD41)-positive MP numbers compared with volunteers. Mixed fungal septic patients showed significantly elevated annexin V and CD41-positive particle numbers on day 1 (P < 0.05) compared with the non-fungal septic group. Adhesive platelet marker (CD42a) harbouring vesicles were negligible in the non-fungal group, while fungal septic patients showed significantly elevated numbers in all measurements (P < 0.01). Particles from activated platelets (PAC1) had elevated numbers in the first and fifth study days compared with non-fungal septic patients (P < 0.05). Conclusions The measurement of CD42a- and PAC1-positive microparticles may provide important additional information which can help to improve the early instalment of antifungal therapy of severe septic patients.

Elevated Plasma Hemoglobin Levels Increase Nitric Oxide Consumption in Experimental and Clinical Acute Pulmonary Thromboembolism

Objectives:We examined whether experimental lung embolization with autologous blood clots or with the infusion of microspheres increase cell-free hemoglobin levels and nitric oxide consumption by plasma samples from anesthetized lambs. These parameters were also measured in patients with acute pulmonary thromboembolism at baseline conditions and after thrombolysis, and in healthy controls. Design:Controlled animal and clinical studies. Setting:University research laboratory and university hospital. Subjects:Sheep and humans. Interventions:Anesthetized lambs were embolized with intravenous injections of autologous blood clots or repeated injections of 300 &mgr;m microspheres. Control animals received saline. Blood samples were drawn from patients with acute pulmonary thromboembolism at baseline conditions and after thrombolytic therapy with streptokinase or alteplase. Measurements and Main Results:Hemodynamic measurements were performed and plasma cell-free hemoglobin concentrations were measured. A nitric oxide consumption assay was used to measure nitric oxide consumption by plasma samples. Embolization with blood clots or microspheres increased mean pulmonary artery pressure from ~15 to ~40 mm Hg in lambs. Both plasma hemoglobin concentrations and nitric oxide consumption increased in proportion to the hemodynamic alterations and correlated significantly. Patients with acute pulmonary thromboembolism had higher plasma hemoglobin concentrations and nitric oxide consumption than healthy controls. Thrombolysis with streptokinase or alteplase further increased both parameters, which peaked 1–3 days after thrombolysis. Conclusions:Our results show consistent evidence indicating a new mechanism involving increased hemoglobin decompartmentalization and augmented nitric oxide consumption, possibly contributing to the hemodynamic derangement of acute pulmonary thromboembolism.

Time course of platelet aggregation during thrombolytic treatment of massive pulmonary embolism.

We studied changes in platelet aggregation and fibrinogen levels during thrombolysis with massive or submassive pulmonary embolism. Fifteen patients were randomized into ultrahigh-dose streptokinase (UH-SK n = 8) or alteplase (tPA n = 7) groups. Arterial blood samples were taken before and after thrombolysis every 4 h between 4 and 36 h, and once daily between 2 and 30 days. In-vitro platelet aggregation was examined as spontaneous (0.9% NaCl) and induced aggregation with adrenaline 10 μmol/l, collagen 2 μg/ml and ADP 10 μmol/l. D-dimer and fibrinogen were measured every 8 h on first day, and later as above. In the UH-SK group, adrenaline-induced platelet aggregation decreased at 4 and 8 h compared with baseline (P < 0.03). Adrenaline-induced platelet aggregation was significantly lower in the UH-SK group than in the tPA group at 36 h and on day 3 (P < 0.03). Platelet aggregation induced by ADP was lower at 4 h than at baseline in the UH-SK group (P < 0.05). Collagen-induced platelet aggregation was lower at 4 and 8 h than at baseline (P < 0.05) in the UH-SK group. Compared with baseline, fibrinogen levels decreased in both groups after thrombolysis. D-dimer levels were elevated in both groups at 8 h (tPA group, P < 0.0004; UH-SK group, P < 0.05). Spontaneous platelet aggregation, major bleeding or re-embolism was not documented. Platelet aggregation decreased after thrombolysis with UH-SK for 12 h, in comparison tPA caused an insignificant decrease. Fibrinogen level decreased with UH-SK treatment for 5 days but in case of tPA we could not measure significant changes. According to our findings, tPA is a more suitable drug but streptokinase is also effective because of its cost–benefit ratio.

The effect of Na-selenite treatment on the oxidative stress–antioxidants balance of multiple organ failure

PURPOSE Our study tested the hypothesis that sodium (Na)-selenite expression treatment can reduce oxidative stress and increase plasma antioxidants, whereas modulating white blood cell antigen expression in severe sepsis. Selenite is a well known cofactor of glutathione peroxidases and other antioxidant enzymes; therefore, one may expect an antioxidant effect of treatment. MATERIALS We randomized 40 severe septic patients into treatment and control groups. Treatment group (n = 21) received 1000-μg/2 hours Na-selenite load, followed by a 1000-μg/die medication. Oxidative stress markers, including malondialdehyde, maximal free radical production, and plasma antioxidants: free sulfhydryl groups, glutathione levels, and superoxide dismutase and catalase enzyme activity were measured. RESULTS According to our results, the treatment regime successfully restored serum selenium levels. Treatment group developed a significant malondialdehyde increase by the fifth study day, whereas reactive oxygen species production decreased significantly. Reduced glutathione and plasma sulfhydryl groups showed no significant difference. Treatment group showed deteriorated expression of CD11a and slight increase of CD49d expression on monocytes throughout our study. CONCLUSIONS Although our Na-selenite treatment regime successfully restored the selenium deficiency of severe septic patients, antioxidant and white blood cell antigen expression modulating effect of the therapy was not observed in our patient group.

Matrix Metalloproteinases as Drug Targets in Acute Pulmonary Embolism

Acute pulmonary embolism is a critical condition associated with increased mortality. Lung embolization causes acute pulmonary hypertension and right ventricle afterload. Global heart ischemia supervenes and may lead to severe shock and death. In this article, we reviewed current literature supporting the idea that abnormal matrix metalloproteinase (MMP) activity contributes to acute pulmonary embolism-induced hemodynamic changes. While low MMP levels are usually found in normal lung tissues, it is well known that inflammation and lung injury increase MMP expression and activity. This is probably due to recruitment and migration of inflammatory cells from the circulation to lung tissues. In addition, recent studies have shown increased MMP levels and activity in the right ventricle from animals with acute pulmonary embolism. Such increases in proteolytic activity were associated with increased cardiac troponin I in serum, suggesting a possible role for MMPs in cardiomyocyte injury during acute pulmonary embolism. These alterations have justified the use of doxycycline as an MMP inhibitor in acute pulmonary embolism. We review current evidence indicating that MMPs are targets in this critical condition. MMP inhibition apparently exerts antihypertensive effects and protects against cardiomyocyte injury caused by acute pulmonary embolism.

Increases in circulating matrix metalloproteinase-9 levels following fibrinolysis for acute pulmonary embolism.

INTRODUCTION Fibrinolyis is one of the first line therapies in high risk pulmonary embolism (PE) according to current guidelines. Previous studies showed that fibrinolytic therapy with tPA (tissue plasminogen activator, or alteplase) upregulates the concentrations of matrix metalloproteinases (MMPs) and contributes to hemorrhagic transformation after cardioembolic stroke. However, no previous study has described the circulating MMPs levels following fibrinolysis for acute PE. MATERIALS AND METHODS We serially measured the circulating levels of MMPs (MMP-9 and MMP-2) and their endogenous inhibitors, the tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 in alteplase and in streptokinase-treated patients with acute PE by gelatin zymography and by enzyme-linked immunosorbent assays, respectively. RESULTS We found that therapy of PE streptokinase or with alteplase is associated increased pro-MMP-9, but not MMP-2, concentrations for up to 24hours, whereas no significant changes were found in TIMP-1 or TIMP-2 concentrations. This alteration returned to normal 3 to 5days after thrombolysis. This is the first study reporting on MMPs alterations following fibrinolysis for acute PE. CONCLUSIONS We found transient increases in circulating pro-MMP-9 levels following fibrinolysis for acute PE. Our findings support the hypothesis that increased MMP-9 levels may underlie the risk of intracerebral hemorrhage or other bleeding complication of thrombolysis for acute PE, and the use of MMP inhibitors may decrease such risk.

Antagonistic sepsis markers: Serum gelsolin and actin/gelsolin ratio

OBJECTIVES For appropriate sepsis care, prognostic laboratory markers are mandatory. The aim of our study was to evaluate the predictive value of serum actin, gelsolin and the recently defined actin/gelsolin ratio during sepsis by comparison it to classical clinical and inflammatory laboratory parameters. DESIGN & METHODS We analyzed sera of severe septic (n=32) and SIRS (n=12) patients for 5days. Ophthalmologic patients (n=27) served as controls. Besides serum actin, gelsolin and actin/gelsolin ratios classical laboratory parameters (WBC count, serum procalcitonin, hsCRP) and clinical scores (APACHE II, SAPS II, SOFA), were also assessed. RESULTS Septic patients showed significantly decreased first-day gelsolin levels and increased actin/gelsolin ratios compared to SIRS patients (p<0.05), furthermore, non-survivors had significantly lower gelsolin levels compared to survivors (p<0.05). Non-survivors had 11.4-fold higher 2nd day actin/gelsolin ratios than survivors. Besides procalcitonin (PCT) and hsCRP, gelsolin and actin/gelsolin ratios also proved to be useful in discriminating SIRS from sepsis in the ICU (p<0.05). Gelsolin had similar prognostic value to PCT when assessing 7-day mortality and the predictive capacity of the first-day actin/gelsolin ratios was similar to that of APACHE II score regarding ICU mortality in severe sepsis. CONCLUSIONS Serum gelsolin and actin/gelsolin ratio might serve as efficient complementary prognostic markers in sepsis. However, for daily clinical usage, an automated laboratory assay of actin and gelsolin is still needed to be developed.

Comparison of VividTrac®, Airtraq®, King Vision®, Macintosh Laryngoscope and a Custom-Made Videolaryngoscope for difficult and normal airways in mannequins by novices

BackgroundDirect laryngoscopy remains the gold standard for endotracheal intubation and is preferred by experienced operators. However, an increasing number of reports currently support videolaryngoscopy, particularly for novice users. The widespread use of videolaryngoscopy may be limited due to financial limitations, especially in low-income countries. Therefore, affordable single-use scopes are now becoming increasingly popular. We sought to compare these new scopes with direct laryngoscopes and the previously tested videolaryngoscopes in mannequins by novices.MethodsFifty medical students were recruited to serve as novice users. Following brief, standardized training, students were asked to execute endotracheal intubation with each of the devices, including the Airtraq®, a custom-made videolaryngoscope, the King Vision®, the Macintosh laryngoscope and the VividTrac®, on an airway trainer (Laerdal Airway Management Trainer®) in normal and difficult airway scenarios. We evaluated the time to and the proportion of successful intubation, the best view of the glottis, esophageal intubation, dental trauma and user satisfaction.ResultsWe observed no differences in esophageal intubation. However, intubation-related times, the view of the glottis and operator satisfaction were significantly better throughout the study with the commercial videolaryngoscopes. In comparison, the custom-made videolaryngoscope performance proved to be similar to that of the Macintosh laryngoscope. The VividTrac® performance was similar (P > 0.05) or significantly better than that of the King Vision® in both scenarios.ConclusionsBased upon our results, the Airtraq®, King Vision® and VividTrac® were superior to the Macintosh laryngscope in both normal and difficult airway scencarios for novice users. In particular, our study is the first to report that the VividTrac® shows promise for further clinical evaluation.