G. Nöldge-Schomburg

Bβ15-42 (FX06) reduces pulmonary, myocardial, liver, and small intestine damage in a pig model of hemorrhagic shock and reperfusion

Objective:The fibrin-derived peptide Bβ15-42 (also called FX06) has been shown to reduce myocardial infarct size following ischemia/reperfusion. Hemorrhagic shock (HS) followed by volume resuscitation represents a similar scenario, whereby a whole organism is vulnerable to reperfusion injury. Design:We subjected male farm-bred landrace pigs (∼30 kg) to HS by withdrawing blood to a mean arterial pressure of 40 mm Hg for 60 minutes. Pigs were then resuscitated with shed blood and crystalloids for 60 minutes, and at this time, FX06 (2.4 mg/kg, n = 8) or vehicle control (phosphate buffered saline; 2.4 mg/kg, n = 7) was injected as an intravenous bolus. Setting:University hospital laboratory. Subjects:Anesthetized male farm-bred landrace pigs. Measurements and Main Results:Data are presented as mean ± sd. Five hours after resuscitation, controls presented acute lung injury (Pao2/Fio2-ratio <300 mm Hg; extra-vascular lung water index (marker for lung injury): 9.0 ± 1.8 mL/kg) and myocardial dysfunction/damage (cardiac index: 4.3 ± 0.25 L/min/m2; stroke volume index: 30 ± 6 mL/m2; cardiac TnT levels: 0.58 ± 0.25 ng/mL). In contrast, FX06-treated animals showed significantly improved pulmonary and circulatory function (Pao2/Fio2-ratio >*400 mm Hg; extra-vascular lung water index: *5.2 ± 2.1 mL/kg, cardiac index: *6.3 ± 1.4 L/min/m2; stroke volume index: *51 ± 11 mL/m2; cardiac TnT levels: *0.11 ± 0.09 ng/mL; *p < 0.05). Also, tissue oxygenation (tpO2; mm Hg) was significantly improved during reperfusion in FX06-treated pigs when compared with controls (liver 51 ± 4 vs. *65 ± 4; serosa 44 ± 5 vs. *55 ± 7; mucosa 14 ± 4 vs. *26 ± 4). Finally, FX06 reduced accumulation of myeloperoxidase-positive cells (mainly neutrophils) in myocardium, liver, and small intestine and reduced interleukin-6 plasma levels (*p < 0.05; compared with controls). Conclusion:We conclude that in a pig model of HS and reperfusion, administration of FX06 during reperfusion protects shock- susceptible organs such as heart, lung, liver, and small intestine.

A comprehensive study of survival, tissue damage, and neurological dysfunction in a murine model of cardiopulmonary resuscitation after potassium-induced cardiac arrest.

There are only few strategic and therapeutic options to improve the functional outcome of patients after cardiac arrest and resuscitation (CPR). The pathophysiology of reperfusion injury after global ischemia is not completely understood. We present here a murine model of cardiac arrest and resuscitation that allows an analysis of the pathophysiology of reperfusion injury, especially focusing on survival, tissue damage, and functional neurological parameters. Under systemic hemodynamic monitoring, male C57BL/6J mice were subjected to 3 min of a potassium-induced cardiac arrest. After resuscitation under controlled conditions, mice were observed and neurologically scored for 72 h post-CPR. As a control, sham-treated animals were provided. In addition, blood samples were drawn and organs were removed for a histological analysis. Here, global I/R led to functional and histological reperfusion damage. The overall mortality up to day 3 post-CPR was 54%. Resuscitated animals developed marked functional neurologic deficits, as assessed by Rotarod and elevated plus-maze testing. Histological examinations and blood analyses of CPR animals revealed significant leukocyte tissue infiltration and morphological damage of brain, lung, and kidneys. In summary, mice undergoing CPR after cardiac arrest present distinct neurological deficits, marked organ damage, and a 54% mortality rate. Our highly standardized and reproducible model of mice resuscitation provides a means for a better understanding of the post-CPR pathophysiology and thus opens new perspectives to develop relevant therapeutic approaches to minimize global I/R injury.

Therapeutic injection of parp inhibitor ino-1001 preserves cardiac function in porcine myocardial ischemia and reperfusion without reducing infarct size

Pharmacological protection from myocardial reperfusion injury, despite plenty of approaches, has still not been realized in humans. We studied the putative infarct size (IS)-sparing capacity of poly(ADP-ribose)polymerase inhibitor, INO-1001, and focused on cardiac functional recovery during reperfusion. Male farm-bred Landrace pigs were subjected to 1-h left anterior descending coronary artery occlusion followed by 3 h of reperfusion (control). Infarct size was determined by triphenyltetrazolium chloride/Evans blue staining. Plasma markers of myocardial injury (troponin T, creatine kinase, lactate dehydrogenase) were determined upon protocol completion. Cardiac function was continuously assessed via pulmonary and femoral artery catheters. INO-1001 (1 mg/kg) was administered upon reperfusion in the treatment group. As a positive control, untreated pigs were subjected to ischemic preconditioning (10-min left anterior descending coronary artery occlusion followed by 15-min reperfusion before the intervention). Ischemic preconditioning reduced myocardial damage reflected by a smaller IS and lower plasma markers of myocardial injury. INO-1001 did not reduce IS but significantly improved functional recovery (increased stroke volume, cardiac index, and mixed venous oxygen saturation) during reperfusion compared with vehicle-treated control and ischemic preconditioning. Although we could not confirm the IS-sparing capacities of poly(ADP-ribose)polymerase inhibitor, INO-1001, the drug holds the potential of hemodynamic improvement during reperfusion.

Hydrocortisone reduces the beneficial effects of toll-like receptor 2 deficiency on survival in a mouse model of polymicrobial sepsis.

Introduction Toll-like receptors (TLRs) play a crucial role in early host defense against microorganisms. Toll-like receptor 2 (TLR2) polymorphisms have a prevalence of 10%; functional defects of TLR2 are associated with higher susceptibility toward gram-positive bacteria, and TLR2 deficiency has been associated with an impaired adrenal stress response. In the present study, we compared endogenous corticosterone production of wild-type (WT) and TLR2-deficient (TLR2−/−) mice and analyzed survival after hydrocortisone therapy during sepsis induced by cecal ligation and puncture (CLP). Methods Male C57BL/6J (WT); and B6.129-Tlr2tm1Kir/J (TLR2−/−) mice were subjected to CLP or sham operation and randomly assigned to postoperative treatment with either hydrocortisone (5 mg/kg) or vehicle (n = 10 mice/group). Survival was documented for an observation period of 48 h. Endogenous corticosterone production following hydrocortisone treatment and lipoteichoic acid (LTA) exposure, interleukin 6 (IL-6) and IL-1&bgr; plasma levels, and blood counts were determined following sham operation or CLP using another n = 5 mice/group. Statistical analysis was performed using analysis of variance/Bonferroni. Results TLR2−/− mice exhibited a lack of suppression and an attenuated increase in endogenous corticosterone production following hydrocortisone or LTA treatment, respectively. After CLP, TLR2−/− mice exhibited an uncompromised adrenal stress response, higher IL-6 levels, and increased survival compared with WT controls (75 vs. 35%; P < 0.05). Hydrocortisone therapy of TLR2−/− mice completely abolished this advantage (decrease in survival to 45%, P < 0.05 vs. vehicle-treated TLR2−/− mice) and was associated with decreased IL-1&bgr; plasma concentrations. Conclusions Toll-like receptor 2 deficiency is associated with an uncompromised adrenal stress response and increased survival rates during polymicrobial sepsis. Hydrocortisone treatment increases mortality of septic TLR2−/− mice, suggesting that hydrocortisone therapy might be harmful for individuals with functional TLR2 polymorphisms.

Accurate and continuous measurement of oxygen deficit during haemorrhage in pigs

OBJECTIVE Haemorrhagic shock can cause organ failure and high mortality. Uncontrolled bleeding, a predetermined bleeding volume or blood pressure controlled bleeding are traditionally used to study haemorrhagic shock. These models are influenced by compensatory mechanisms preventing accurate knowledge about the severity of cellular insult. We describe the use of a method for continuous measurement of oxygen deficit during haemorrhage in pigs. METHODS We defined a cumulative oxygen deficit of approximately 100mL/kg as the primary endpoint for severe haemorrhage. For continuous assessment of oxygen deficit a metabolic monitor (Deltatrac II, Datex-Ohmeda Instrumentation Corp., Helsinki, Finland) was used. Data are presented as mean+/-SD; (*)P<0.05 was considered to be significant. RESULTS 17 out of 22 anaesthetised male pigs achieved a mean cumulative oxygen deficit of 106+/-3 mL/kg (range: 95-117 mL/kg) by withdrawing an average blood volume of 47+/-6 mL/kg over 1h. Mean arterial blood pressure (MAP) fell from 83+/-19 to 22+/-7mmHg (baseline versus shock), heart rate increased from 83+/-7 to 147+/-37min(-1). Venous base excess changed from 4.8+/-2.4 to -12.5+/-3.4 mmol/L and venous lactate increased from 1.5+/-0.4 to 13.3+/-2.4 mmol/L after haemorrhage. Two pigs (11%) died during the haemorrhagic shock phase. The traditional method of assessing haemorrhage (measuring blood volume lost) showed only a poor correlation with heart rate (r=0.3872; P=0.1540), MAP (r=0.3901; P=0.1505), mixed venous oxygen saturation (svO(2); r=0.0944; P=0.7379) or cardiac index (CI; r=0.2101; P=0.4523). Cumulative oxygen deficit correlated significantly better with heart rate (r=0.7175; P=0.0026), MAP (r=0.5039; P=0.0556), svO(2) (r=0.7084; P=0.0031) or CI (r=0.6260; P=0.0125). CONCLUSION We describe a model to study haemorrhagic shock based on the cumulative oxygen deficit. We believe that the use of a metabolic monitor to measure oxygen deficit in our model represents an improvement on the current available methods to study the effects of haemorrhagic shock.

A double blind, single centre, sub-chronic reperfusion trial evaluating FX06 following haemorrhagic shock in pigs

OBJECTIVE Haemorrhagic shock causes ischaemia and subsequent fluid resuscitation causes reperfusion injury, jointly resulting in high morbidity and mortality. We tested whether the anti-inflammatory fibrin-derived peptide, Bbeta(15-42), also called FX06, is tissue protective in a model of haemorrhagic shock. METHODS In a pig model, we standardised the severity of haemorrhagic shock by achieving a cumulative oxygen deficit of approximately 100ml/kg body weight by withdrawing blood over a period of 1h. This was followed by resuscitation with shed blood and full electrolyte solution, and pigs were monitored for 3 days. At reperfusion, 17 pigs were randomly assigned to FX06 or solvent treatment. RESULTS FX06-treated pigs demonstrated improved cardiac function (stroke volume index: 67ml/m(2) versus 33ml/m(2)), decreased troponin T release in the early reperfusion (0.24ng/ml versus 0.78ng/ml), decreased AST levels after 24h (106U/l versus 189U/l) and decreased creatinine levels after 24h (108micromol/l versus 159micromol/l). Furthermore, FX06-treated pigs demonstrated preservation of the gut/blood barrier, while controls demonstrated high endotoxin plasma levels indicating translocation of bacteria and/or its products (0.2EU/ml versus 24.3EU/ml) after 24h. This study also demonstrates a significantly improved neurological performance in the FX06 group as determined by S100beta serum levels (0.72microg/l versus 1.25microg/l) after 48h and neurological deficit scores (11 versus 70) after 24h. CONCLUSION FX06 - when administered as an adjunct to fluid resuscitation therapy - is organ protective in pigs. Further investigations are warranted to reveal the protective mechanism of FX06.

Akuter Blutverlust in der operativen Medizin

Der akute Blutverlust stellt seit jeher eines der schwierigsten Probleme in der Notfall- und operativen Medizin dar. Auser dem Volumenverlust ist auch der Verlust der einzelnen Blutkomponenten zu beachten, da das Blut den vielfaltigen Anforderungen nur bei optimalem Zusammenwirken seiner Bestandteile gerecht werden kann. Neben dem Transport von Sauerstoff, Nahrstoffen, Stoffwechselmetaboliten und Komponenten des korpereigenen Immunsystems nimmt das Blut auch eine zentrale Rolle bei der Steuerung der intrinsischen Gerinnung ein. Aus diesem Grund ist beim akuten Blutverlust nicht nur an den Volumenverlust und den Verlust an Sauerstofftransportkapazitat zu denken, sondern auch an den Verlust gerinnungsaktiver Komponenten. Besonders in der Kombination mit anderen schweren systemischen Reaktionen wie beim Schock oder wahrend einer Sepsis sind Gerinnungsstorungen keine Seltenheit. Ziel dieses Kapitels ist es, die gebrauchlichsten Richtgrosen zur Therapie von akuten Blutverlusten in der operativen Medizin unter Einbeziehung der von der Bundesarztekammer formulierten Leitlinien darzulegen.