Roman Pohorecki

Aprotinin reduces interleukin-8 production and lung neutrophil accumulation after cardiopulmonary bypass.

Pulmonary neutrophil entrapment and resultant oxidative injury is thought to be the primary mechanism of cardiopulmonary bypass (CPB) induced lung injury.Interleukin-8 (IL-8), a potent neutrophil chemoattractant induced by cytokines, including tumor necrosis factor-alpha (TNF), is found in increased concentrations in bronchial alveolar lavage fluid (BALF) in lung inflammation. Since aprotinin reduces TNF release during CPB, the effects of aprotinin on BALF IL-8 concentrations and neutrophil levels were determined after CPB in adult humans. Study patients were equally divided into a control group (n = 8, Group 1) and an aprotinin treated group (n = 8, Group 2). In vitro neutrophil chemotaxis was done with volunteer neutrophils using three different chemoattractants: 1) N-formyl-1-methionyl-1-leucyl-1-phenylalanine (FMLP); 2) the supernatant of a human bronchial epithelial cell culture line, A549, after 24 h of TNF stimulation with or without aprotinin or N-alpha-tosyl-L-lysine chloromethyl ketone (TLCK) (a potent protease inhibitor), and 3) BALF. Aprotinin treatment significantly (P < 0.05) reduced post-CPB BALF IL-8 concentrations and percentage of neutrophils. In vitro, BALF from Group 1 had significantly greater chemotactic ability when compared with Group 2. The TNF stimulated A549 cell culture supernatant had significantly (P < 0.05) greater chemotactic ability than control supernatant, while aprotinin and TLCK significantly (P < 0.05) reduced this chemotactic ability. These results demonstrate that aprotinin blunts IL-8 production and reduces neutrophil lung accumulation post-CPB. (Anesth Analg 1996;83:696-700)

Aprotinin Enhances the Endogenous Release of Interleukin-10 After Cardiac Operations

BACKGROUND Cardiopulmonary bypass (CPB) is characterized by the systemic release of proinflammatory cytokines, such as tumor necrosis factor-alpha and the interleukins 1 and 6, as well as endogenous antiinflammatory cytokines, including interleukin-10 (IL-10). Glucocorticoids reduce tumor necrosis factor-alpha plasma concentrations while enhancing IL-10 plasma concentrations after CPB. Aprotinin, a serine protease inhibitor used primarily to reduce blood loss after CPB, reduces CPB-induced proinflammatory cytokine tumor necrosis factor-alpha release similarly to glucocorticoids. This study evaluates the effect of full-dose aprotinin on the plasma concentrations of IL-10 after CPB. METHODS Twenty adults were randomized into a control (group C, n = 10) and a full-dose aprotinin-treated group (group A, n = 10). Plasma levels of IL-10 were measured by enzyme-linked immunosorbent assay technique at baseline (before anesthetic induction), and at 1 and 24 hours after CPB termination. RESULTS A significant (p < 0.05) increase of IL-10 occurred in both groups at 1 and 24 hours after termination of CPB when compared with the same group at baseline. In group A, the increase in IL-10 was significantly greater than in group C (p < 0.05) at 24 hours after CPB. CONCLUSIONS These results demonstrate an endogenous antiinflammatory response generated after CPB, characterized by IL-10 release, that is enhanced by aprotinin therapy. This study demonstrates a unique antiinflammatory activity of aprotinin that may be of clinical significance.

Ischemic brain injury in vitro: protective effects of NMDA receptor antagonists and calmidazolium

Excessive Ca2+ influx through NMDA receptor-coupled channels has been linked to neuronal cell death. Using an in vitro model of transient brain ischemia, we investigated possible protective effects of NMDA receptor antagonists ketamine or MK-801 and of calmidazolium, an inhibitor of intracellular Ca2(+)-activated proteins. Brain ischemia/recovery was simulated in isolated hippocampal slices and injury monitored by measurement of ATP levels. Omission of both glucose and oxygen (but not oxygen alone) for 20 min led to persistent ATP deficits after 4 h recovery. Addition of ketamine or MK-801 at 1 microM permitted ATP to recover within 1 h, as did addition of calmidazolium at 10 microM. Our findings are consistent with other reports that NMDA receptor antagonists can protect neuronal tissue from ischemic damage. The role of inappropriately activated Ca2(+)-mediated signaling processes in the mechanism(s) of such injury is suggested by the protection also seen with calmidazolium, an inhibitor of calmodulin and other structurally related proteins such as calpain(s) and protein kinase C. The inhibition of intracellular Ca2+ target proteins may be an alternative for protection of the brain against injury due to insults that activate NMDA receptors.

Cigarette smoking reduces endogenous airway nitric oxide production during cardiopulmonary bypass in humans

C ytokines, including tumor necrosis factor (TNF) and interleukin-lp, are known to increase inducible nitric oxide synthase (iNOS) expression (1,2) with subsequent increased local production of nitric oxide (NO). TNF is among the cytokines known to be systemically released during cardiopulmonary bypass (CPB) in humans (3). Cigarette smoking is known to reduce exhaled NO concentration in humans (4), while smokers are also known to have increased pulmonary complications after CPB (5). Endogenous NO is known to be a bronchodilator (6), and is known to be the nonadrenergic neurotransmitter of bronchodilator nerves in human airways (7). This study was undertaken to evaluate endogenous airway NO production during CPB in a group of currently smoking males, compared to a group who quit smoking at least 30 days but no longer than 6 mo prior to surgery, and a third group who quit smoking more than 6 mo prior to surgery.

Plasma lipid concentrations correlate inversely with CPB-induced interleukin-6 release.

PurposeCardiopulmonary bypass (CPB) is characterized by translocation of intestinal endotoxin and subsequent endogenous production of the pro-inflammatory cytokine interleukin-6 (IL-6). Plasma lipid fractions, especially high density lipoproteins, bind and neutralize endotoxin and, therefore, inhibit endotoxin-induced macrophage cytokine production, including IL-6. Increased IL-6 plasma levels have been implicated in adverse consequences associated with CPB. Previous studies demonstrated large interpatient variability in IL-6 plasma levels after CPB. The purpose of this study was to evaluate the relationship between plasma lipid concentrations and the concentrations of IL-6 following CPB in humans.MethodsIn a prospective study, a group of 15 patients selected to exclude variables known to influence post-CPB plasma levels of IL-6 (preoperative left ventricular ejection fraction > 45%, similar durations of aortic cross clamping and total CPB time, similar temperature control during CPB, and avoidance of platelet transfusion and shed mediastinal blood re-infusion), IL-6 was measured at baseline, one and 24 hr post-CPB.ResultsInterleukin-6 plasma concentrations (mean ± SD) increased at one (142 ± 89 pg·ml−1,P < 0.05) and 24 (129 ± 82 pg·ml−1,P < 0.05) hr post-CPB compared with baseline (1,5 ± 1 pg·ml−1) concentrations. An inverse correlation was found between IL-6 plasma concentrations at one hour post-CPB and plasma cholesterol concentrations (r = -0.592,P = 0.02), high density lipoprotein (r = -0.595,P = 0.02), and low density lipoprotein (r = -0.656,P = 0.01).ConclusionsThese results suggest that plasma lipids attenuate the production of IL-6 during CPB and may partly explain the variability of interpatient levels of IL-6 reported post-CPB by others.RésuméObjectifLa circulation extracorporelle (CEC) est caractérisée par la translocation de l’endotoxine intestinale et la production endogène subséquente de la cytokine interleukine-6 (IL-6) pro-inflammatoire. Des fractions de lipides plasmatiques, surtout les lipoprotéines de haute densité, se fixent à l’endotoxine et la neutralisent et, par conséquent, inhibent la production de cytokine macrophage induite par l’endotoxine, incluant IL-6. Laccroissement des niveaux plasmatiques de IL-6 a été présumé comme responsable des conséquences défavorables associées à la CEC. Des études antérieures ont démontré une grande variabilité dans les niveaux plasmatiques de IL-6 à la suite d’une CEC. Le but de cette étude était d’évaluer la relation entre les concentrations de lipides plasmatiques et les concentrations de IL-6 après une CEC chez les humains.MéthodesDans une étude prospective, un groupe de 15 patients a été sélectionné en excluant les variables connues pour influencer les niveaux plasmatiques de IL-6 post CEC (fraction d’éjection ventriculaire gauche préopératoire > 45%, durées similaires de clampage aortique et de temps total de CEC, contrôle similaire de la température pendant la CEC et suppression de la transfusion de plaquettes ainsi que de la reperfusion du sang médiastinal dérivé), IL-6 a été mesurée au début, puis une heure et 24 heures post CEC.RésultatsLes concentrations plasmatiques d’inlerleukine-6 (moyenne ± écart type) s’accroissent à une heure (142 ± 89 pg·ml−1,P < 0,05) et à 24 heures (129 ± 82 pg·ml−1,P < 0,05) post CEC par rapport aux concentrations de base (1,5 ± 1 pg·ml−1). On a constaté une corrélation inverse entre les concentrations plasmatiques de IL-6 à une heure post CEC et les concentrations de cholestérol plasmatique (r = -0,592,P = 0,02), de lipoprotéines de haute densité (r = -0,595,P = 0,02) et de lipoprotéines de basse densité (r = -0,656,P = 0,01).ConclusionCes résultats suggèrent que les lipides réduisent la production de IL-6 pendant la CEC et peuvent expliquer partiellement la variabilité interindividuelle des niveaux de IL-6 post CEC rapportés par d’autres chercheurs.

Effects of isoflurane dose, duration of anoxia, and reoxygenation on isoflurane's preservation of energy balance in anoxic isolated hepatocytes

We investigated how the protection of energy status by isoflurane in isolated hepatocytes varied with isoflurane dose, duration of anoxia, and reoxygenation. Hepatocytes were isolated from fed rats and incubated in Krebs buffer under O2/CO2 or N2/CO2 (95/5) for 30 or 90 min, followed by 5 or 30 min of reoxygenation. From measurements of adenosine tri-, di-, and monophosphate (ATP, ADP, AMP) in the cells, energy charge (= [ATP + 1/2 ADP] / [ATP + ADP + AMP]) was calculated to reflect the balance between ATP supply and demand, and total adenine nucleotide (= ATP + ADP + AMP) to indicate the potential maximum ATP level. During 30 min of anoxia, energy charge and total adenine nucleotide steadily increased with isoflurane dose from 0 to 2 minimum alveolar anesthetic concentration, then decreased from 2 to 3 minimum alveolar anesthetic concentration. In short incubations (30–35 min) at 1 minimum alveolar anesthetic concentration isoflurane, there was a modest decrease in energy charge during anoxia, partially prevented by isoflurane and completely reversed by reoxygenation, and no decrease in total adenine nucleotide. In long incubations (90–120 min), there were large decreases in both energy charge and total adenine nucleotide during anoxia, with partial and no reversal by reoxygenation, respectively. Isoflurane partly prevented decreases in both energy charge and total adenine nucleotide during both anoxia and reoxygenation. We conclude that at doses in the clinical range, isoflurane partially protected isolated hepatocytes against decreases in both energy charge and total adenine nucleotide occurring either during short (reversible) or long (irreversible) anoxia. Other data from this study suggest that isoflurane may have protected in part by inhibiting AMP formation, an obligatory step in nucleotide degradation.

Risk and Uncertainty in Anesthesia

Introduction: Men with long term advanced cancer of the prostate can be considered transitional cancer survivors because many have complex physical, emotional, and psychosocial needs that extend beyond the active treatment period. Methods: Health care providers completed a survey identifying the needs most common to men with advancedprostate cancer. Descriptive statistics were used to describe the sample and analyze the survey data, including means for continuous variables and frequencies for categorical variables. Qualitative content analysis was used to analyze the cancer-related topics suggested by the respondents that were not included in the questionnaire. Results: Thirty providers completed the survey. Mean age of respondent was 46.8 years. The majority of participants reported that their race was White, indicated that they were physicians, and reported that they practiced in outpatient or ambulatory care settings. The respondent’s mean years in the current clinical role, current clinical setting and experience with people with advanced cancer was 17.8 years, 11.0, and 17.3, respectively. The needs identified by the respondents as important (listed from highest to lowest frequency) were help with decisions (92%), help with hands-on care (88%), and referral to community resources (88%), financial assistance (85%), help with anxiety or depression (85%), help with grieving (77%), and help with an advanced directive (73%). The needs that least likely to be addressed by the health care providers in their clinical settings were financial assistance (95%), spiritual care (84%), and help with grieving (58%). Discussion: While community-based physician practices are able to address the direct physical needs, they may have limited ability to provide emotional, spiritual or financial support that are needed by families. Given the large and growing number of long-term survivors, the time has come to develop comprehensive plans of care that integrate palliative care principles throughout all phases of the cancer journey.

Isoflurane preserves adenosine triphosphate levels in anoxic isolated rat hepatocytes by stimulating glycolytic adenosine triphosphate formation

The hypothesis that general anesthetics protect energy reserves by decreasing energy demand is widely accepted but poorly substantiated.Isoflurane at clinical doses preserved adenosine triphosphate (ATP) levels in anoxic isolated hepatocytes. Specific inhibitors were used to block mitochondrial and/or glycolytic ATP formation to ascertain whether pathways of energy supply or demand, or both, were involved in ATP preservation by isoflurane. Hepatocytes were isolated from fed adult male rats after perfusing livers with Krebs buffer containing collagenase. Cells were incubated in Krebs buffer for 0-30 min at 25 degrees C under N2/CO2 (95%/5%) +/- isoflurane 0.63 mM in liquid phase. Oligomycin, iodoacetate, or fasting were used to block mitochondrial and glycolytic ATP formation. Under anoxia alone, ATP levels declined more slowly in the presence than in the absence of isoflurane, confirming the ATP-protective effect of isoflurane reported previously. With oligomycin plus iodoacetate blocking all ATP formation, ATP decline (representing pure ATP consumption) was not slowed by isoflurane. Isofluranes protective effect recurred when glycolytic ATP supply was restored by incubating with oligomycin only. The protective effect was accompanied by increased lactate accumulation, and both effects--ATP preservation and lactate formation--were similarly dependent on isoflurane concentration. We conclude that the protective effect of isoflurane on energy status in anoxic isolated hepatocytes was not associated with reduced ATP demand but with enhanced ATP supply via stimulation of glycolysis. (Anesth Analg 1996;82:1261-7)