The JNK inhibitor XG-102 protects from ischemic damage with delayed intravenous administration also in the presence of recombinant tissue plasminogen activator.

BACKGROUND: XG-102 (formerly D-JNKI1), a TAT-coupled dextrogyre peptide which selectively inhibits the c-Jun N-terminal kinase, is a powerful neuroprotectant in mouse models of middle cerebral artery occlusion (MCAo) with delayed intracerebroventricular injection. We aimed to determine whether this neuroprotection could also be achieved by intravenous injection of XG-102, which is a more feasible approach for future use in stroke patients. We also tested the compatibility of the compound with recombinant tissue plasminogen activator (rtPA), commonly used for intravenous thrombolysis and known to enhance excitotoxicity. METHODS: Male ICR-CD1 mice were subjected to a 30-min-suture MCAo. XG-102 was injected intravenously in a single dose, 6 h after ischemia. Hippocampal slice cultures were subjected to oxygen (5%) and glucose (1 mM) deprivation for 30 min. rtPA was added after ischemia and before XG-102 administration, both in vitro and in vivo. RESULTS: The lowest intravenous dose achieving neuroprotection was 0.0003 mg/kg, which reduced the infarct volume after 48 h from 62 +/- 19 mm(3) (n = 18) for the vehicle-treated group to 18 +/- 9 mm(3) (n = 5, p < 0.01). The behavioral outcome was also significantly improved at two doses. Addition of rtPA after ischemia enhanced the ischemic damage both in vitro and in vivo, but XG-102 was still able to induce a significant neuroprotection. CONCLUSIONS: A single intravenous administration of XG-102 several hours after ischemia induces a powerful neuroprotection. XG-102 protects from ischemic damage in the presence of rtPA. The feasibility of systemic administration of this promising compound and its compatibility with rtPA are important steps for its development as a drug candidate in ischemic stroke.

New evidence of neuroprotection by lactate after transient focal cerebral ischaemia: extended benefit after intracerebroventricular injection and efficacy of intravenous administration.

BACKGROUND: Lactate protects mice against the ischaemic damage resulting from transient middle cerebral artery occlusion (MCAO) when administered intracerebroventricularly at reperfusion, yielding smaller lesion sizes and a better neurological outcome 48 h after ischaemia. We have now tested whether the beneficial effect of lactate is long-lasting and if lactate can be administered intravenously. METHODS: Male ICR-CD1 mice were subjected to 15-min suture MCAO under xylazine + ketamine anaesthesia. Na L-lactate (2 µl of 100 mmol/l) or vehicle was administered intracerebroventricularly at reperfusion. The neurological deficit was evaluated using a composite deficit score based on the neurological score, the rotarod test and the beam walking test. Mice were sacrificed at 14 days. In a second set of experiments, Na L-lactate (1 µmol/g body weight) was administered intravenously into the tail vein at reperfusion. The neurological deficit and the lesion volume were measured at 48 h. RESULTS: Intracerebroventricularly injected lactate induced sustained neuroprotection shown by smaller neurological deficits at 7 days (median = 0, min = 0, max = 3, n = 7 vs. median = 2, min = 1, max = 4.5, n = 5, p < 0.05) and 14 days after ischaemia (median = 0, min = 0, max = 3, n = 7 vs. median = 3, min = 0.5, max = 3, n = 7, p = 0.05). Reduced tissue damage was demonstrated by attenuated hemispheric atrophy at 14 days (1.3 ± 4.0 mm(3), n = 7 vs. 12.1 ± 3.8 mm(3), n = 5, p < 0.05) in lactate-treated animals. Systemic intravenous lactate administration was also neuroprotective and attenuated the deficit (median = 1, min = 0, max = 2.5, n = 12) compared to vehicle treatment (median = 1.5, min = 1, max = 8, n = 12, p < 0.05) as well as the lesion volume at 48 h (13.7 ± 12.2 mm(3), n = 12 vs. 29.6 ± 25.4 mm(3), n = 12, p < 0.05). CONCLUSIONS: The beneficial effect of lactate is long-lasting: lactate protects the mouse brain against ischaemic damage when supplied intracerebroventricularly during reperfusion with behavioural and histological benefits persisting 2 weeks after ischaemia. Importantly, lactate also protects after systemic intravenous administration, a more suitable route of administration in a clinical emergency setting. These findings provide further steps to bring this physiological, commonly available and inexpensive neuroprotectant closer to clinical translation for stroke.

Significant correction of disease after postnatal administration of recombinant ectodysplasin A in canine X-linked ectodermal dysplasia.

Patients with defective ectodysplasin A (EDA) are affected by X-linked hypohidrotic ectodermal dysplasia (XLHED), a condition characterized by sparse hair, inability to sweat, decreased lacrimation, frequent pulmonary infections, and missing and malformed teeth. The canine model of XLHED was used to study the developmental impact of EDA on secondary dentition, since dogs have an entirely brachyodont, diphyodont dentition similar to that in humans, as opposed to mice, which have only permanent teeth (monophyodont dentition), some of which are very different (aradicular hypsodont) than brachyodont human teeth. Also, clinical signs in humans and dogs with XLHED are virtually identical, whereas several are missing in the murine equivalent. In our model, the genetically missing EDA was compensated for by postnatal intravenous administration of soluble recombinant EDA. Untreated XLHED dogs have an incomplete set of conically shaped teeth similar to those seen in human patients with XLHED. After treatment with EDA, significant normalization of adult teeth was achieved in four of five XLHED dogs. Moreover, treatment restored normal lacrimation and resistance to eye and airway infections and improved sweating ability. These results not only provide proof of concept for a potential treatment of this orphan disease but also demonstrate an essential role of EDA in the development of secondary dentition.

Comparison of results of intravenous infusion of anistreplase versus streptokinase in acute myocardial infarction.

This randomized study compares the coronary perfusion rate in patients with acute myocardial infarction (AMI) treated with 2 different intravenous thrombolytic agents: streptokinase 1.5 million U given over 60 minutes and anisoylated human plasminogen streptokinase activator complex (anistreplase) administrated as a bolus of 30 U over 5 minutes. One hundred seventy-five patients (149 men and 26 women, mean age 54 years) have been included in this study. Eighty-nine patients were treated with anistreplase and 86 patients with streptokinase. AMI was inferior in 54 patients (61%) in the anistreplase group and in 54 patients (63%) in the streptokinase group. It was anterior in 35 (40%) and 32 (37%) patients, respectively. Coronary angiography and ventriculography were performed at a mean time (+/- SEM) of 207 +/- 11 minutes after the beginning of thrombolysis in 170 patients. A perfusion score grade of 2 or 3 according to the Thrombolysis in Myocardial Infarction trial was found in 63 patients (72%) in the anistreplase group and in 56 patients (68%) in the streptokinase group (p = NS). Severe bleeding occurred in 7 patients (8%) after anistreplase and in 6 patients (7%) after streptokinase. No cerebral hemorrhage occurred. Nine patients (5%) died during their hospital stay: 6 after anistreplase and 3 after streptokinase. It is concluded that intravenous administration of anistreplase or streptokinase is efficient and safe. Coronary patency 207 minutes after fibrinolysis, incidence of adverse events and mortality are similar in both groups.

Intravenous streptomycin dosing regimen in a patient undergoing hemodialysis: Plasma level monitoring and pharmacokinetic simulation

Introduction: Streptomycin, as other aminoglycosides, exhibits concentration-dependent bacterial killing but has a narrow therapeutic window. It is primarily eliminated unchanged by the kidneys. Data and dosing information to achieve a safe regimen in patients with chronic renal failure undergoing hemodialysis (HD) are scarce. Although main adverse reactions are related to prolonged, elevated serum concentrations, literature recommendation is to administer streptomycin after each HD. Patients (or Materials) and Methods: We report the case of a patient with end-stage renal failure, undergoing HD, who was successfully treated with streptomycin for gentamicin-resistant Enterococcus faecalis bacteremia with prosthetic arteriovenous fistula infection. Streptomycin was administered intravenously 7.5 mg/kg, 3 hours before each dialysis (3 times a week) during 6 weeks in combination with amoxicillin. Streptomycin plasma levels were monitored with repeated blood sampling before, after, and between HD sessions. A 2-compartment model was used to reconstruct the concentration time profile over days on and off HD. Results: Streptomycin trough plasma-concentration was 2.8 mg/L. It peaked to 21.4 mg/L 30 minutes after intravenous administration, decreased to 18.2 mg/L immediately before HD, and dropped to 4.5 mg/L at the end of a 4-hour HD session. Plasma level increased again to 5.7 mg/L 2 hours after the end of HD and was 2.8 mg/L 48 hours later, before the next administration and HD. The pharmacokinetics of streptomycin was best described with a 2-compartment model. The computer simulation fitted fairly well to the observed concentrations during or between HD sessions. Redistribution between the 2 compartments after the end of HD reproduced the rebound of plasma concentrations after HD. No significant toxicity was observed during treatment. The outcome of the infection was favorable, and no sign of relapse was observed after a follow-up of 3 months. Conclusion: Streptomycin administration of 7.5 mg/kg 3 hours before HD sessions in a patient with end-stage renal failure resulted in an effective and safe dosing regimen. Monitoring plasma levels along with pharmacokinetic simulation document the suitability of this dosing scheme, which should replace current dosage recommendations for streptomycin in HD.

Beta-adrenergic blockade and intravenous nutrient-induced thermogenesis in lean and obese women.

Continuous respiratory exchange measurements were performed in nine obese and eight lean women for 1 h before, 3 h during, and 1 h after the intravenous administration of a nutrient mixture infused at twice the postabsorptive resting energy expenditure (REE). This experiment was conducted without or with beta-adrenergic blockade (iv propranolol). Propranolol administration did not change the postabsorptive REE [i.e., 1.03 +/- 0.07 before vs. 1.01 +/- 0.02 kcal/min after administration in lean women and 1.16 +/- 0.04 vs. 1.15 +/- 0.03 kcal/min (NS) in obese women]. The mean overall thermogenic response expressed as a percentage of the infused energy was similar in both groups and was not significantly blunted after propranolol infusion [6.9 +/- 0.4 vs. 5.9 +/- 0.6% in the lean women and 7.5 +/- 0.5 vs. 7.1 +/- 0.6% (NS) in the obese women]. During beta-adrenergic blockade the rate of lipid oxidation decreased in the lean group but was unchanged in the obese group and the glycemic response to nutrient administration was significantly higher in both groups than without propranolol. It is concluded that beta-adrenergic blockade has no effect on REE and on intravenous nutrient-induced thermogenesis in both lean and obese women.

Intravenous immunoglobulin for treatment of mild-to-moderate Alzheimer's disease: a phase 2, randomised, double-blind, placebo-controlled, dose-finding trial.

BACKGROUND: Three small trials suggest that intravenous immunoglobulin can affect biomarkers and symptoms of mild-to-moderate Alzheimer's disease. We tested the safety, effective dose, and infusion interval of intravenous immunoglobulin in such patients. METHODS: We did a multicentre, placebo-controlled phase 2 trial at seven sites in the USA and five in Germany. Participants with probable Alzheimer's disease aged 50-85 years were randomly assigned (by a computer-generated randomisation sequence, with block sizes of eight) to infusions every 4 weeks (0·2, 0·5, or 0·8 g intravenous immunoglobulin per kg bodyweight, or placebo) or infusions every 2 weeks (0·1, 0·25, or 0·4 g/kg, or placebo). Patients, caregivers, investigators assessing outcomes, and staff at imaging facilities and the clinical research organisation were masked to treatment allocation, but dispensing pharmacists, the statistician, and the person responsible for final PET analyses were not. Treatment was masked with opaque pouches and infusion lines. The primary endpoint was median area under the curve (AUC) of plasma amyloid β (Aβ)(1-40) between the last infusion and the final visit (2 weeks or 4 weeks depending on infusion interval) in the intention-to-treat population. The trial is registered at ClinicalTrials.gov (NCT00812565) and controlled-trials.com (ISRCTN64846759). FINDINGS: 89 patients were assessed for eligibility, of whom 58 were enrolled and 55 included in the primary analysis. Median AUC of plasma Aβ(1-40) was not significantly different for intravenous immunoglobulin compared with placebo for five of the six intervention groups (-18·0 [range -1347·0 to 1068·5] for 0·2 g/kg, -364·3 [-5834·5 to 1953·5] for 0·5 g/kg, and -351·8 [-1084·0 to 936·5] for 0·8 g/kg every 4 weeks vs -116·3 [-1379·0 to 5266·0] for placebo; and -13·8 [-1729·0 to 307·0] for 0·1 g/kg, and -32·5 [-1102·5 to 451·5] for 0·25 g/kg every 2 weeks vs 159·5 [51·5 to 303·0] for placebo; p>0·05 for all). The difference in median AUC of plasma Aβ(1-40) between the 0·4 g/kg every 2 weeks group (47·0 [range -341·0 to 72·5]) and the placebo group was significant (p=0·0216). 25 of 42 (60%) patients in the intervention group versus nine of 14 (64%) receiving placebo had an adverse event. Four of 42 (10%) patients in the intravenous immunoglobulin group versus four of 14 (29%) receiving placebo had a serious adverse event, including one stroke in the intervention group. INTERPRETATION: Intravenous immunoglobulin may have an acceptable safety profile. Our results did not accord with those from previous studies. Longer trials with greater power are needed to assess the cognitive and functional effects of intravenous immunoglobulin in patients with Alzheimer's disease.

Effets hémodynamiques d'un inhibiteur de l'effet vasculaire de la vasopressine chez des patients avec insuffisance cardiaque congestive [Hemodynamic effects of an inhibitor of the vascular effects of vasopressin in patients with congestive heart failure]

To assess the role of vasopressin (AVP) in congestive heart failure (CHF), we investigated 10 patients with CHF refractory to conventional treatment, before and 60 minutes after intravenous administration of 5 micrograms/kg of d(CH2)5Tyr(Me)AVP, a specific antagonist of AVP at the vascular receptor level. Heart rate, systemic arterial pressure, pulmonary arterial pressure, pulmonary capillary wedge pressure, cardiac index by thermodilution, and cutaneous blood flow by laser-Doppler technique were measured. In 9 patients there was no significant hemodynamic and cutaneous blood flow response to the AVP antagonist. Plasma AVP was 2.3 +/- 0.8 pg/ml and plasma osmolality 284 +/- 14 mosm/kg H2O. The tenth patient had the most severe CHF. His plasma AVP was 55 pg/ml and plasma osmolality 290 mosm/kg. He responded to the AVP antagonist with a marked decrease in systemic arterial pressure from 115/61 to 79/41 mm Hg, in pulmonary arterial pressure from 58/31 to 33/13 mm Hg and in pulmonary capillary wedge pressure from 28 to 15 mm Hg. Simultaneously cardiac index increased from 1.1 to 2.21 X min-1 X m-2 and cutaneous blood flow rose 5-fold. Thus, most patients with CHF have only moderately elevated plasma AVP and its role in determining peripheral vascular resistance appears to be limited. AVP may become important in rare patients presenting with marked hemodynamic instability and very high plasma AVP.

In vivo synergism of ceftobiprole and vancomycin against experimental endocarditis due to vancomycin-intermediate Staphylococcus aureus.

The efficacy of ceftobiprole combined with vancomycin was tested against two vancomycin-intermediate Staphylococcus aureus (VISA) strains, PC3 and Mu50, in rats with experimental endocarditis. Animals with infected aortic vegetations were treated for 3 days with doses simulating the kinetics after intravenous administration in humans of (i) the standard dose of ceftobiprole of 500 mg every 12 h (b.i.d.) (SD-ceftobiprole), (ii) a low dose of ceftobiprole of 250 mg b.i.d. (LD-ceftobiprole), (iii) a very low dose of ceftobiprole of 125 mg b.i.d. (VLD-ceftobiprole), (iv) SD-vancomycin of 1 g b.i.d., or (v) LD- or VLD-ceftobiprole combined with SD-vancomycin. Low dosages of ceftobiprole were purposely used to highlight positive drug interactions. Treatment with SD-ceftobiprole sterilized 12 of 14 (86%) and 10 of 13 (77%) vegetations infected with PC3 and Mu50, respectively (P < 0.001 versus controls). In comparison, LD-ceftobiprole sterilized 10 of 11 (91%) vegetations infected with PC3 (P < 0.01 versus controls) but only 3 of 12 (25%) vegetations infected with Mu50 (P > 0.05 versus controls). VLD-ceftobiprole and SD-vancomycin alone were ineffective against both strains (≤8% sterile vegetations). In contrast, the combination of VLD-ceftobiprole and SD-vancomycin sterilized 7 of 9 (78%) and 6 of 14 (43%) vegetations infected with PC3 and Mu50, respectively, and the combination of LD-ceftobiprole and SD-vancomycin sterilized 5 of 6 (83%) vegetations infected with Mu50 (P < 0.05 versus controls and monotherapy). Thus, ceftobiprole monotherapy simulating standard therapeutic doses was active against VISA experimental endocarditis. Moreover, subtherapeutic LD- and VLD-ceftobiprole synergized with ineffective vancomycin to restore efficacy. Hence, combining ceftobiprole with vancomycin broadens the therapeutic margin of these two compounds against VISA infections.

Acute hemodynamic effect of a vascular antagonist of vasopressin in patients with congestive heart failure.

To assess the role of arginine vasopressin (AVP) in congestive heart failure (CHF), 10 patients with CHF refractory to conventional treatment were studied before and 60 minutes after intravenous administration of 5 micrograms/kg of d(CH2)5Tyr(Me)AVP, a specific antagonist of AVP at the vascular receptor level. Heart rate, systemic arterial pressure, pulmonary arterial pressure, pulmonary capillary wedge pressure, cardiac index by thermodilution and cutaneous blood flow by laser-Doppler technique were measured. In 9 patients with no significant hemodynamic and cutaneous blood flow response to the AVP antagonist, baseline values (mean +/- standard deviation) were: heart rate, 77 +/- 14 beats/min; systemic arterial pressure, 120/79 +/- 18/8 mm Hg; pulmonary arterial pressure, 42/21 +/- 12/8 mm Hg; pulmonary capillary wedge pressure, 19 +/- 7 mm Hg; cardiac index, 2.2 +/- 0.6 liters/min/m2; plasma AVP, 2.3 +/- 0.8 pg/ml; and plasma osmolality, 284 +/- 14 mosm/kg H2O. The tenth patient had the most severe CHF. His plasma AVP level was 55 pg/ml and plasma osmolality was 290 mosm/kg. He responded to the AVP antagonist with a decrease in systemic arterial pressure from 115/61 to 79/41 mm Hg, in pulmonary arterial pressure from 58/31 to 33/13 mm Hg and in pulmonary capillary wedge pressure from 28 to 15 mm Hg. Simultaneously, cardiac index increased from 1.1 to 2.2 liters/min/m2 and heart rate from 113 to 120 beats/min; cutaneous blood flow increased 5-fold.(ABSTRACT TRUNCATED AT 250 WORDS)

Bacterial flagellin elicits innate immune defenses and cardiac dysfunction in vivo

Résumé Les agents pathogènes responsables d'infection entraînent chez l'hôte deux types de réponses immunes, la première, non spécifique, dite immunité innée, la seconde, spécifique à l'agent concerné, dite immunité adaptative. L'immunité innée, qui représente la première ligne de défense contre les pathogènes, est liée à la reconnaissance par les cellules de l'hôte de structures moléculaires propres aux micro-organismes (« Pathogen-Associated Molecular Patterns », PAMPs), grâce à des récepteurs membranaires et cytoplasmiques (« Pattern Recognition Receptors », PRRs) identifiant de manière spécifique ces motifs moléculaires. Les récepteurs membranaires impliqués dans ce processus sont dénommés toll-like récepteurs, ou TLRS. Lorsqu'ils sont activés par leur ligand spécifique, ces récepteurs activent des voies de signalisation intracellulaires initiant la réponse inflammatoire non spécifique et visant à éradiquer l'agent pathogène. Les deux voies de signalisation impliquées dans ce processus sont la voie des « Mitogen-Activated Protein Kinases » (MAPKs) et celle du « Nuclear Factor kappaB » (NF-κB), dont l'activation entraîne in fine l'expression de protéines de l'inflammation dénommées cytokines, ainsi que certaines enzymes produisant divers autres médiateurs inflammatoires. Dans certaines situations, cette réponse immune peut être amplifiée de manière inadéquate, entraînant chez l'hôte une réaction inflammatoire systémique exagérée, appelée sepsis. Le sepsis peut se compliquer de dysfonctions d'organes multiples (sepsis sévère), et dans sa forme la plus grave, d'un collapsus cardiovasculaire, définissant le choc septique. La défaillance circulatoire du choc septique touche les vaisseaux sanguins d'une part, le coeur d'autre part, réalisant un tableau de «dysfonction cardiaque septique », dont on connaît mal les mécanismes pathogéniques. Les bactéries à Gram négatif peuvent déclencher de tels phénomènes, notamment en libérant de l'endotoxine, qui active les voies de l'immunité innée par son interaction avec un toll récepteur, le TLR4. Outre l'endotoxine, la plupart des bactéries à Gram négatif relâchent également dans leur environnement une protéine, la flagelline, qui est le constituant majeur du flagelle bactérien, organelle assurant la mobilité de ces micro-organismes. Des données récentes ont indiqué que la flagelline active, dans certaines cellules, les voies de l'immunité innée en se liant au récepteur TLRS. On ne connaît toutefois pas les conséquences de l'interaction flagelline-TLRS sur le développement de l'inflammation et des dysfonctions d'organes au cours du sepsis. Nous avons par conséquent élaboré le présent travail en formulant l'hypothèse que la flagelline pourrait déclencher une telle inflammation et représenter ainsi un médiateur potentiel de la dysfonction d'organes au cours du sepsis à Gram négatif, en nous intéressant plus particulièrement àl'inflammation et à la dysfonction cardiaque. Dans la première partie de ce travail, nous avons étudié les effets de la flagelline sur l'activation du NF-κB et des MAPKs, et sur l'expression de cytokines inflammatoires au niveau du myocarde in vitro (cardiomyocytes en culture) et in vivo (injection de flagelline recombinante à des souris). Nous avons observé tout d'abord que le récepteur TLRS est fortement exprimé au niveau du myocarde. Nous avons ensuite démontré que la flagelline active la voie du NF-κB et des MAP kinases (p38 et JNK), stimule la production de cytokines et de chemokines inflammatoires in vitro et in vivo, et entraîne l'activation de polynucléaires neutrophiles dans le tissu cardiaque in vivo. Finalement, au plan fonctionnel, nous avons pu montrer que la flagelline entraîne une dilatation et une réduction aiguë de la contractilité du ventricule gauche chez la souris, reproduisant les caractéristiques de la dysfonction cardiaque septique. Dans la deuxième partie, nous avons déterminé la distribution du récepteur TLRS dans les autres organes majeurs de la souris (poumon, foie, intestin et rein}, et avons caractérisé dans ces organes l'effet de la flagelline sur l'activation du NF-κB et des MAPKs, l'expression de cytokines, et l'induction de l'apoptose. Nous avons démontré que le TLRS est exprimé de façon constitutive dans ces organes, et que l'injection de flagelline y déclenche les cascades de l'immunité innée et de processus apoptotiques. Finalement, nous avons également déterminé que la flagelline entraîne une augmentation significative de multiples cytokines dans le plasma une à six heures après son injection. En résumé, nos données démontrent que la flagelline bactérienne (a) entraîne une inflammation et une dysfonction importantes du myocarde et (b) active de manière très significative les mécanismes d'immunité innée dans les principaux organes et entraîne une réponse inflammatoire systémique. Par conséquent, la flagelline peut représenter un médiateur puissant de l'inflammation et de la dysfonction d'organes, notamment du coeur, au cours du choc septique déclenché par les bactéries à Gram négatif. Summary Pathogenic microorganisms trigger two kinds of immune responses in the host. The first one is immediate and non-specific and is termed innate immunity, whereas the second one, specifically targeted at the invading agent, is termed adaptative immunity. Innate immunity, which represents the first line of defense against invading pathogens, confers the host the ability to recognize molecular structures common to many microbial pathogens, ("Pathogen-Associated Molecular Patterns", PAMPs), through cytosolic or membrane-associated receptors ("Pattern Recognition Receptors", PRRs), the latter being represented by a family of receptors termed "toll-like receptors or TLRs". Once activated by the binding of their specific ligand, these receptors activate intracellular signaling pathways, which initiate the non-specific inflammatory response aimed at eradicating the pathogens. The two pathways implicated in this process are the mitogen-activated protein kinases (MAPK) and the nuclear factor kappa B (NF-κB) signaling pathways, whose activation elicit in fine the expression of inflammatory proteins termed cytokines, as well as various enzymes producing a wealth of additional inflammatory mediators. In some circumstances, the innate immune response can become amplified and dysregulated, triggering an overwhelming systemic inflammatory response in the host, identified as sepsis. Sepsis can be associated with multiple organ dysfunction (severe sepsis), and in its most severe form, with cardiovascular collapse, defming septic shock. The cardiovascular failure associated with septic shock affects blood vessels as well as the heart, resulting in a particular form of acute heart failure termed "septic cardiac dysfunction ", whose pathogenic mechanisms remain partly undefined. Gram-negative bacteria can initiate such phenomena, notably by releasing lipopolysaccharide (LPS), which activates innate immune signaling by interacting with its specific toll receptor, the TLR4. Besides LPS, most Gram-negative bacteria also release flagellin into their environment, which is the main structural protein of the bacterial flagellum, an appendage extending from the outer bacterial membrane, responsible for the motility of the microorganism. Recent data indicated that flagellin activate immune responses upon binding to its receptor, TLRS, in various cell types. However, the role of flagellin/TLRS interaction in the development of inflammation and organ dysfunction during sepsis is not known. Therefore, we designed the present work to address the hypothesis that flagellin might trigger such inflammatory responses and thus represent a potential mediator of organ dysfunction during Gram-negative sepsis, with a particular emphasis on cardiac inflammation and contractile dysfunction. In the first part of this work, we investigated the effects of flagellin on NF-κB and MAPK activation and the generation of pro-inflammatory mediators within the heart in vitro (cultured cardiomyocytes) and in vivo (injection of recombinant flagellin into mice). We first observed that TLRS protein is strongly expressed by the myocardium. We then demonstrated that flagellin activates NF-κB and MAP kinases (p38 and JNK), upregulates the transcription of pro-inflammatory cytokines and chemokines in vitro and in vivo, and stimulates the activation of polymorphonuclear neutrophils within the heart in vivo. Finally, we demonstrated that flagellin triggers acute cardiac dilation, and a significant reduction of left ventricular contractility, mimicking characteristics of clinical septic cardiac dysfunction. In the second part, we determined the TLRS distribution in other mice major organs (lung, liver, gut and kidney) and we characterized in these organs the effects of flagellin on NF-κB and MAPK activation, on the expression of pro-inflammatory çytokines, and on the induction of apoptosis. We demonstrated that TLRS protein is constitutively expressed and that flagellin activates prototypical innate immune responses and pro-apoptotic pathways in all these organs. Finally, we also observed that flagellin induces a significant increase of multiple cytokines in the plasma from 1 to 6 hours after its intravenous administration. Altogether, these data provide evidence that bacterial flagellin (a) triggers an important inflammatory response and an acute dysfunction of the myocardium, and (b) significantly activates the mechanisms of innate immunity in most major organs and elicits a systemic inflammatory response. In consequence, flagellin may represent a potent mediator of inflammation and multiple organ failure, notably cardiac dysfunction, during Gram-negative septic shock.

Cytostatic lung perfusion results in heterogeneous spatial regional blood flow and drug distribution: evaluation of different cytostatic lung perfusion techniques in a porcine model.

OBJECTIVES: Comparison of doxorubicin uptake, leakage and spatial regional blood flow, and drug distribution was made for antegrade, retrograde, combined antegrade and retrograde isolated lung perfusion, and pulmonary artery infusion by endovascular inflow occlusion (blood flow occlusion), as opposed to intravenous administration in a porcine model. METHODS: White pigs underwent single-pass lung perfusion with doxorubicin (320 mug/mL), labeled 99mTc-microspheres, and Indian ink. Visual assessment of the ink distribution and perfusion scintigraphy of the perfused lung was performed. 99mTc activity and doxorubicin levels were measured by gamma counting and high-performance liquid chromatography on 15 tissue samples from each perfused lung at predetermined localizations. RESULTS: Overall doxorubicin uptake in the perfused lung was significantly higher (P = .001) and the plasma concentration was significantly lower (P < .0001) after all isolated lung perfusion techniques, compared with intravenous administration, without differences between them. Pulmonary artery infusion (blood flow occlusion) showed an equally high doxorubicin uptake in the perfused lung but a higher systemic leakage than surgical isolated lung perfusion (P < .0001). The geometric coefficients of variation of the doxorubicin lung tissue levels were 175%, 279%, 226%, and 151% for antegrade, retrograde, combined antegrade and retrograde isolated lung perfusion, and pulmonary artery infusion by endovascular inflow occlusion (blood flow occlusion), respectively, compared with 51% for intravenous administration (P = .09). 99mTc activity measurements of the samples paralleled the doxorubicin level measurements, indicating a trend to a more heterogeneous spatial regional blood flow and drug distribution after isolated lung perfusion and blood flow occlusion compared with intravenous administration. CONCLUSIONS: Cytostatic lung perfusion results in a high overall doxorubicin uptake, which is, however, heterogeneously distributed within the perfused lung.

Reconstituted human polyclonal plasma-derived secretory-like IgM and IgA maintain the barrier function of epithelial cells infected with an enteropathogen.

Intravenous administration of polyclonal and monoclonal antibodies has proven to be a clinically valid approach in the treatment, or at least relief, of many acute and chronic pathologies, such as infection, immunodeficiency, and a broad range of autoimmune conditions. Plasma-derived IgG or recombinant IgG are most frequently used for intravenous or subcutaneous administration, whereas a few IgM-based products are available as well. We have established recently that secretory-like IgA and IgM can be produced upon association of plasma-derived polymeric IgA and IgM with a recombinant secretory component. As a next step toward potential future mucosal administration, we sought to unravel the mechanisms by which these secretory Igs protect epithelial cells located at the interface between the environment and the inside of the body. By using polarized epithelial Caco-2 cell monolayers and Shigella flexneri as a model enteropathogen, we found that polyspecific plasma-derived SIgA and SIgM fulfill many protective functions, including dose-dependent recognition of the antigen via formation of aggregated immune complexes, reduction of bacterial infectivity, maintenance of epithelial cell integrity, and inhibition of proinflammatory cytokine/chemokine production by epithelial cells. In this in vitro model devoid of other cellular or molecular interfering partners, IgM and secretory IgM showed stronger bacterial neutralization than secretory IgA. Together, these data suggest that mucosally delivered antibody preparations may be most effective when combining both secretory-like IgA and IgM, which, together, play a crucial role in preserving several levels of epithelial cell integrity.