Impact of age on cardiovascular function, inflammation, and oxidative stress in experimental asphyxial cardiac arrest.

BACKGROUND: Advanced age is an independent predictor of poor outcome after cardiac arrest (CA). From experimental studies of regional ischemia-reperfusion injury, advanced age is associated with larger infarct size, reduced organ function, and augmented oxidative stress. The objective of this study was to investigate the effect of age on cardiovascular function, oxidative stress, inflammation, and endothelial activation after CA representing global ischemia-reperfusion. METHODS: Aged (26 months) and young (5 months) rats were subjected to 8 min of asphyxia induced CA, resuscitated and observed for 360 min. Left ventricular pressure-derived cardiac function was measured at baseline and 360 min after CA. Blood samples obtained at baseline, 120 min, and 360 min after CA were analyzed for IL-1ß, IL-6, IL-10, TNF-α, elastase, sE-selectin, sL-selectin, sI-CAM1, hemeoxygenase-1 (HO-1) and protein carbonyl. Tissue samples of brain, heart, kidney, and lung were analyzed for HO-1. RESULTS: Cardiac function, evaluated by dP/dtmax and dP/dtmin , was decreased after CA in both young and aged rats, with no group differences. Mean arterial pressure increased after CA in young, but not old rats. Aged rats showed significantly higher plasma levels of elastase and sE-selectin after CA, and there was a significant different development over time between groups for IL-6 and IL-10. Young rats showed higher levels of HO-1 in plasma and renal tissue after CA. CONCLUSION: In a rat model of asphyxial CA, advanced age is associated with an attenuated hyperdynamic blood pressure response and increased endothelial activation.

Expression of NK cell and monocyte receptors in critically ill patients--potential biomarkers of sepsis.

UNLABELLED: Sepsis is characterized by activation of both the innate and adaptive immune systems as a response to infection. During sepsis, the expression of surface receptors expressed on immune competent cells, such as NKG2D and NKp30 on NK cells and TLR4 and CD14 on monocytes, is partly regulated by pro- and anti-inflammatory mediators. In this observational study, we aimed to explore whether the expression of these receptors could be used as diagnostic and/or prognostic biomarkers in sepsis. Patients with severe sepsis or septic shock (n = 21) were compared with critically ill non-septic patients (n = 15). Healthy volunteers (n = 15) served as controls. To elucidate variations over time, all patients were followed for 4 days. Cell surface expression of NKG2D, NKp30, TLR4 and CD14 and serum levels of IL-1ß, IL-6, IFN-γ, TNF-α, IL-4 and IL-10 was estimated by flow cytometry. We found that NK cell expression of NKG2D and monocyte expression of CD14 were lower in the septic patients compared with the non-septic patients, both at ICU admission and during the observation period (P < 0.01 for all comparisons). Both at ICU admission, and during the observation period, levels of IL-6 and IL-10 were higher in the septic patients compared with the non-septic patients (P < 0.001 for all comparisons). CONCLUSION: As both NKG2D and CD14 levels appear to distinguish between septic and non-septic patients, both NKG2D and CD14 may be considered potential diagnostic biomarkers of severe sepsis and septic shock.

Pulmonary function after hemorrhagic shock and resuscitation in a porcine model.

BACKGROUND: Hemorrhagic shock may trigger an inflammatory response and acute lung injury. The combination adenosine, lidocaine (AL) plus Mg(2+) (ALM) has organ-protective and anti-inflammatory properties with potential benefits in resuscitation.The aims of this study were to investigate: (1) pulmonary function and inflammation after hemorrhagic shock; (2) the effects of ALM/AL on pulmonary function and inflammation. METHODS: Pigs (38 kg) were randomized to: sham + saline (n = 5); sham + ALM/AL (n = 5); hemorrhage control (n = 11); and hemorrhage + ALM/AL (n = 9). Hemorrhage animals bled to a mean arterial pressure (MAP) of 35 mmHg for 90 min, received resuscitation with Ringer's acetate and 20 ml of 7.5% NaCl with ALM to a minimum MAP of 50 mmHg, after 30 min shed blood and 0.9% NaCl with AL were infused. Hemorrhage controls did not receive ALM/AL. Primary endpoints were pulmonary wet/dry ratio, PaO2 /FiO2 ratio (partial pressure of arterial oxygen to the fraction of inspired oxygen), cytokine and protein measurements in bronchoalveolar lavage fluid (BALF) and lung tissue, neutrophil invasion and blood flow in lung tissue. RESULTS: In the hemorrhage groups, wet/dry ratio increased significantly compared with the sham groups. PaO2 /FiO2 ratio decreased during shock but normalized after resuscitation. BALF did not indicate significant pulmonary inflammation, oxidative stress or increased permeability. Intervention with ALM caused a temporary increase in pulmonary vascular resistance and reduced urea diffusion across the alveolar epithelia, but had no effect on wet/dry ratio. CONCLUSION: Hemorrhagic shock and resuscitation did not cause acute lung injury or pulmonary inflammation. The question whether ALM/AL has the potential to attenuate acute lung injury is unanswered.

Brain death increases COX-1 and COX-2 expression in the renal medulla in a pig model.

BACKGROUND: Brain death is linked to a systemic inflammatory response that includes prostaglandins and cytokines among its mediators. The levels of cyclooxygenase-1 and cyclooxygenase-2 (COX-1 and COX-2) affect graft survival, but it remains unknown whether these enzymes are modified during brain death. The aims of this study were to investigate the organ expression of COX and to analyse the cytokine response in the plasma, cerebrospinal fluid (CSF), and organs in a porcine model of intracerebral haemorrhage and brain death. METHODS: Twenty pigs were randomly assigned to either a brain death group or a control group. Brain death was induced by an intracerebral injection of blood, and the animals were observed over the next 8 h. Tissue samples were tested for COX-1, COX-2 messenger RNA (mRNA) expression (heart, lung, and kidney), haeme oxygenase-1 (HO-1) (kidney), interleukin-1ß (IL-1ß), IL-6, IL-8, IL-10, and tumour necrosis factor-α. These cytokines were also measured at eight time points in the plasma and CSF. RESULTS: At the organ level, the levels of COX-1 and COX-2 mRNA expression were increased only in the renal medulla (P = 0.03 and P = 0.02, respectively). The cytokine levels in the tissue, plasma, and CSF revealed no differences between the groups. HO-1 expression decreased (P = 0.0088). CONCLUSION: Brain death increases the expression of COX-1 and COX-2 mRNA in the renal medulla. The release of cytokines into the plasma and CSF did not vary between the groups.

Effect of remote ischemic conditioning on dendritic cell number in blood after renal transplantation--flow cytometry in a porcine model.

Delayed graft function after transplantation increases the risk of rejection. Remote ischemic conditioning (rIC) consists of repetitive, brief, non-damaging periods of ischemia in a limb. For reasons not fully understood, rIC protects the target organ against subsequent ischemia-reperfusion injury. Because ischemic endothelium attracts dendritic cells (DCs), we hypothesised that rIC protects the organ by "trapping" circulating DCs in the limb exposed to rIC. With fewer DCs thus available to infiltrate the graft, a strong T-cell mediated immune response toward the graft is less likely. To test this hypothesis, we measured the number of circulating DCs in a porcine model of renal transplantation with and without rIC. Brain death was induced in eight 65-kg donor pigs. After 22 h of cold ischemia, the kidneys were transplanted into sixteen 15-kg recipient pigs. The recipients were randomised to either non-rIC or rIC before reperfusion of the graft and observed 10 h after reperfusion. The number of DCs was determined by flow cytometry. DCs were identified on the basis of forward- and side-scatter characteristics of CD14-negative mononuclear cells with expression of CD172a. Dendritic cells were subclassified as either plasmacytoid (pDCs) (CD172a(dim), CD4(+), CD14(-)) or conventional (cDCs) (CD172a(high), CD4(-), CD14(-)). Remote ischemic conditioning did not affect the number of circulating cDCs or pDCs within the 10h after transplantation studied. Regardless of rIC, the number of pDCs decreased after graft reperfusion and then returned to baseline levels. In contrast, the number of circulating cDCs increased after reperfusion and later returned to baseline levels.

Erythropoietin does not attenuate renal dysfunction or inflammation in a porcine model of endotoxemia.

BACKGROUND: Erythropoietin (EPO) is a multifunctional cytokine with anti-apoptotic, anti-inflammatory, and organ protective effects. EPO protects against ischemia-reperfusion injuries, and recent reports suggest that EPO also prevents organ dysfunction in experimental sepsis. The aims of this study were to determine whether EPO prevents endotoxemia-induced organ dysfunction in a porcine model and to characterize the immunomodulatory and anti-apoptotic effects of EPO. METHODS: Twenty-eight pigs were randomly assigned to three groups: (1) endotoxemia treated with EPO 5000 IU/kg, (2) endotoxemia treated with placebo, and (3) a sham group anesthetized and submitted to sham operation without treatment. A laparotomy was performed, and a flow probe was placed around the left renal artery, which allowed renal blood flow (RBF) measurements. Endotoxemia was induced by an infusion of lipopolysaccharide. After 2 h, the infusion was reduced to a maintenance dose and the animals were fluid resuscitated. The glomerular filtration rate (GFR), RBF, renal oxygen consumption, and plasma cytokines [interleukin (IL)-1ß, IL-6, IL-8, IL-10, and tumor necrosis factor-alpha] were analyzed. Renal biopsies were analyzed for cytokine content and apoptosis. RESULTS: Endotoxemia elicited impaired renal function, estimated as GFR, and increased the levels of renal apoptotic cells, with no modifying effect of EPO. Furthermore, EPO had no effect on RBF, renal oxygen consumption, or the systemic hemodynamic response to endotoxemia. EPO did not modify the inflammatory response, measured as changes in cytokine levels in plasma and organs. CONCLUSION: EPO did not confer renal protection in this fluid-resuscitated porcine model of endotoxemia, and EPO did not modify the inflammatory response.

Brief report: biomarkers of aortic vascular prosthetic graft infection in a porcine model with Staphylococcus aureus.

Aortic vascular prosthetic graft infection (AVPGI) with Staphylococcus aureus is a feared post-operative complication. This study was conducted to evaluate the clinical signs and potential biomarkers of infection in a porcine AVPGI model. The biomarkers evaluated were: C-reactive protein (CRP), fibrinogen, white blood cells (WBC), major histocompatibility complex II (MHC II) density, lymphocyte CD4:CD8 ratio and tumour necrosis factor-alpha (TNF-α) in vitro responsiveness. Sixteen pigs were included in the study, and randomly assigned into four groups (n = 4): "SHAM" pigs had their infra-renal aorta exposed by laparotomy; "CLEAN" pigs had an aortic graft inserted; "LOW" and "HIGH" pigs had an aortic graft inserted and, subsequently, S. aureus were inoculated on the graft material (5 × 10(4) colony-forming units [CFU] and 1 × 10(6) CFU, respectively). Biomarkers were evaluated prior to surgery and on day 2, 5, 7, and 14 post-operatively in blood samples. Of all biomarkers evaluated, CRP was superior for diagnosing S. aureus AVPGI in pigs, with a sensitivity of 0.86 and a specificity of 0.75.

The early IL-6 and IL-10 response in trauma is correlated with injury severity and mortality.

BACKGROUND: Trauma has previously been shown to influence interleukin (IL)-6 and IL-10 levels, but the association of injury severity and mortality with IL-6 and IL-10 responses in the early phase of accidental trauma remains to be investigated. We wished to describe serum levels of IL-6 and IL-10 in the first 24 h after trauma and to assess the relationship with severity of injury and mortality. METHODS: Prospective, descriptive cohort study in a Level 1 trauma centre, Copenhagen, Denmark. We included 265 consecutive adult trauma patients admitted directly from the accident scene during an 18-month period. Serum levels of IL-6 and IL-10 were measured upon arrival and at 6, 12, and 24 h after admittance using an enzyme-linked immunosorbent assay. Correlation analysis was used to assess the relationship between Injury Severity Score (ISS) and levels of IL-6 and IL-10. Analysis of variance was used to describe the IL-6 and IL-10 concentrations in relation to 30-day mortality in a mixed-effect model repeated measures analysis. RESULTS: Mortality was 10.9% (29/265) at 30 days. A significant increase of both IL-6 and IL-10 concentrations was found over time, and a significant correlation was found between ISS and the levels of both IL-6 and IL-10 at all sampling points. Serum concentrations of IL-6 and IL-10 were significantly higher in patients not surviving 30 days (P<0.0001). CONCLUSION: The early systemic inflammatory response measured as IL-6 and IL-10 in serum is correlated with injury severity and 30-day mortality following trauma.

Cytokine changes during warm ischemia and reperfusion of the pig liver with or without preconditioning.

BACKGROUND: Hepatic inflow occlusion results in ischemia-reperfusion injury. The aim of the present porcine study was to investigate whether the pro- and anti-inflammatory cytokine response is involved in mediating the protective effect of ischemic preconditioning (IPC) during, and after warm liver ischemia. METHODS: Fifteen randomized pigs--7 non-IPC and 8 (IPC)--underwent laparotomy followed by 60 min of total ischemia with or without IPC continued by 3 h of reperfusion. Plasma cytokines (IL-6, IL-8, IL-10, and TNF-alpha) were measured during the study period as well as liver parameters (alanine-aminotransferase, alkaline phosphatase, bilirubin, and prothrombin time). RESULTS: In the IPC group, IL-6 increased significantly during reperfusion compared to baseline and the non-IPC group. TNF-alpha increased nonsignificantly in the non-IPC group, while the levels remained stable in the IPC group. IL-8 and IL-10 increased in both groups after reperfusion. Only minor differences were observed in liver parameters. CONCLUSIONS: Warm liver ischemia with or without IPC activates inflammatory cytokines. IL-6 increased significantly in the IPC group compared to the non-IPC group, while the opposite was observed for TNF-alpha. These cytokine changes may be involved in the hepatoprotective mechanism induced by IPC.

Fibrinogen substitution improves whole blood clot firmness after dilution with hydroxyethyl starch in bleeding patients undergoing radical cystectomy: a randomized, placebo-controlled clinical trial.

SUMMARY BACKGROUND: Infusion of artificial colloids such as hydroxyethyl starch (HES) induces coagulopathy to a greater extent than simple dilution. Several studies have suggested that the coagulopathy could be corrected by substitution with a fibrinogen concentrate. OBJECTIVES: The aims of the present prospective, randomized, placebo-controlled trial were to investigate the hemostatic effect of a fibrinogen concentrate after coagulopathy induced by hydroxyethyl starch in patients experiencing sudden excessive bleeding during elective cystectomy. METHODS: Twenty patients were included. Blood loss was substituted 1:1 with HES 130/0.4. At a dilution level of 30%, patients were randomly selected for intra-operative administration of a fibrinogen concentrate or placebo. The primary endpoint was maximum clot firmness (MCF), as assessed by thromboelastometry. Secondary endpoints were blood loss and transfusion requirements, other thromboelastometry parameters, thrombin generation and platelet function. RESULTS: Whole-blood MCF was significantly reduced after 30% dilution in vivo with HES. The placebo resulted in a further decline of the MCF, whereas randomized administration of fibrinogen significantly increased the MCF. Furthermore, only 2 out of 10 patients randomly chosen to receive fibrinogen substitution required postoperative red blood cell transfusions, compared with 8 out of 10 in the placebo group (P = 0.023). Platelet function and thrombin generation were reduced after 30% hemodilution in vivo, and fibrinogen administration caused no significant changes. CONCLUSIONS: During cystectomy, fluid resuscitation with HES 130/0.4 during sudden excessive bleeding induces coagulopathy that shows reduced whole-blood maximum clot firmness. Randomized administration of fibrinogen concentrate significantly improved maximum clot firmness and reduced the requirement for postoperative transfusion.

Does brain death induce a pro-inflammatory response at the organ level in a porcine model?

BACKGROUND: Organs from brain-dead donors have a poorer prognosis after transplantation than organs from living donors. A possible explanation for this is that brain death might initiate a systemic inflammatory response, elicited by a metabolic stress response or brain ischemia. The aim of this study was to investigate the effect of brain death on the cytokine content in the heart, liver, and kidney. In addition, the metabolic and hemodynamic response caused by brain death was carefully registered. METHODS: Fourteen pigs (35-40 kg) were randomized into two groups (1) eight brain-dead pigs and (2) six pigs only sham operated. Brain death was induced by inflation of an epidurally placed balloon. Blood samples for insulin, glucose, catecholamine, free fatty acids (FAA), and glucagon were obtained during the experimental period of 360 min. At the conclusion of the experiment, biopsies were taken from the heart, liver, and kidney and were analyzed for cytokine mRNA and proteins [tumor necrosis factor alpha (TNF-alpha), interleukin (IL)-6, and IL-10). RESULTS: We found a dramatic response to brain death on plasma levels of epinephrine (P=0.004), norepinephrine (P=0.02), FAA (P=0.0001), and glucagon (P=0.0003) compared with the sham group. There was no difference in cytokine content in any organ between the groups. CONCLUSION: In this porcine model, brain death induced a severe metabolic response in peripheral blood. At the organ level, however, there was no difference in the cytokine response between the groups.

Insulin alters cytokine content in two pivotal organs after brain death: a porcine model.

BACKGROUND: To optimize the quantity and quality of organs available for transplantation, it is crucial to gain further insight into the treatment of brain dead organ donors. In the current study we hypothesized that insulin treatment after brain death alters cytokine content in the heart, liver, and kidney. METHODS: Sixteen brain dead pigs (35-40 kg) were treated with either (1) no insulin [brain dead without insulin treatment treatment (BD)], or (2) insulin infusion intravenously (i.v.) at a constant rate of 0.6 mU/kg/min during 360 min [brain dead with insulin treatment (BD+I)]. Blood glucose was clamped at 4.5 mmol/l by infusion of 20% glucose. Blood samples for insulin, glucose, catecholamines, free fatty acids, and glucagon were obtained during the experimental period. Six hours after brain death biopsies were taken from the heart, liver, and kidney. These were analyzed for cytokine mRNA and proteins [tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-6, and IL-10]. RESULTS: The BD+I compared with the BD animals had lower IL-6 concentrations in the right ventricle of the heart (P=0.001), in the renal cortex (P=0.04) and in the renal medulla (P=0.05), and lower IL-6 mRNA in the renal medulla (P=0.0002). Furthermore, the BD+I animals had lower concentrations in the renal medulla of IL-10 (P=0.01), and tended to have lower TNF-alpha in the renal cortex (P=0.06) than the BD animals. In the right ventricle of the heart TNF-alpha mRNA and IL-10 mRNA were higher in the BD+I than in the BD group (P=0.002 and 0.004). CONCLUSION: Insulin has anti-inflammatory effects on cytokine concentration in the heart and kidney after brain death.

Infusion of hypertonic saline before elective hysterectomy: effects on cytokines and stress hormones.

BACKGROUND: Infusion of hypertonic saline provides early haemodynamic benefits and may affect the immune system. It is unknown if infusion of hypertonic saline affects plasma cytokines and stress hormones after surgery. METHODS: Sixty-two women undergoing abdominal hysterectomy were randomized in a double-blind study to infusion of NaCl 7.5% (HS), NaCl 0.9% (NS4), both 4 ml kg(-1), or NaCl 0.9% 32 ml kg(-1) (NS32) over 20 min. Blood was collected at baseline, 1, 4, and 24 h after surgery (n=34) for the determination of interleukin (IL)-1beta, IL-6, IL-8, IL-10, IL-12, IL-1ra, and tumour necrosis factor-alpha. Serum cortisol and vasopressin were measured at these time points and 48 h after operation. Epinephrine and norepinephrine (n=26) were quantified at baseline, after infusion, 25 min after incision, 1, and 4 h after surgery. Finally, C-reactive protein was measured at baseline, 24, and 48 h after surgery. RESULTS: Surgery and anaesthesia induced well-reported changes in the concentrations of cytokines and hormones. The concentration of norepinephrine briefly increased after infusion of HS and NS32 but not NS4 (P<0.05). Epinephrine was increased 25 min after incision in Group NS32 compared with the other groups (P<0.05). No other differences were found between the groups. CONCLUSIONS: Infusion of a clinically relevant dose of hypertonic saline before hysterectomy appears to have limited effect on the postoperative concentration of selected plasma cytokines and the hormonal stress-response.

Oxygenation and release of inflammatory mediators after off-pump compared with after on-pump coronary artery bypass surgery.

BACKGROUND: In a previous study, we showed that oxygenation was impaired for up to 5 day after conventional coronary artery bypass grafting (CABG). As cardiopulmonary bypass (CPB) may have a detrimental effect on pulmonary function, we hypothesized that coronary revascularization grafting without the use of CPB (OPCAB) would affect post-operative oxygenation and release of inflammatory mediators less compared with CABG. METHODS: Low-risk patients scheduled for elective coronary revascularization were randomly assigned to one of two groups (CABG, n = 17 or OPCAB, n = 18). Two parameters of oxygenation, shunt (%) and ventilation-perfusions mismatch, described as DeltaPO(2) (kPa), were estimated for up to 5 days post-operatively. Systemic release of interleukin (IL)-6, -8 and -10, C-reactive protein (CRP) and neutrophils were measured in peripheral blood samples for up to 3 days post-operatively. The lungs participation in the cytokine response was evaluated from mixed venous blood samples taken within the first 16 h post-operatively. RESULTS: OPCAB was followed by a higher shunt (P = 0.047), with no difference (P = 0.47) in the deterioration of DeltaPO(2) between the groups. OPCAB was followed by an attenuated systemic release of IL-8 (P = 0.041) and IL-10 (P = 0.006), while the release of IL-6 (P = 0.94), CRP (P = 0.121) and neutrophils (P = 0.078) did not differ between the groups. Indications of an uptake of cytokines in the lungs were found after OPCAB. CONCLUSIONS: When comparing OPCAB with CABG, oxygenation was more affected and only part of the systemic inflammatory response was attenuated.

Coagulation, inflammatory, and stress responses in a randomized comparison of open and laparoscopic repair of recurrent inguinal hernia.

BACKGROUND: In previous comparisons of inflammatory and stress responses to open (OR) and laparoscopic (LR) hernia repair, all operations were performed under general anesthesia. Since local anesthesia is widely used for OR, a comparison of this approach with LR seemed relevant. METHODS: Patients with recurrent inguinal hernia were randomized to OR under local anesthesia (n = 30) or LR under general anesthesia (n = 31). The magnitude of the surgical trauma was assessed by measuring markers of coagulation (prothrombin fragment 1 + 2), endothelial activation (von Willebrand factor), inflammation [leukocytes, interleukin-6, -8 and -10, granulocyte macrophage colony-stimulating factor, and C-reactive protein (CRP)], and endocrine stress (cortisol) in blood collected before operation, 4 h postincision, and on postoperative day 2. RESULTS: Leukocyte counts and interleukin-6 and CRP levels increased in both groups, with the CRP increase being significantly greater in the OR group. The other markers did not increase significantly. CONCLUSION: The acute phase response was more pronounced after OR, even when this was done under local anesthesia. Both techniques seemed rather atraumatic.

Evidence that acute hyperinsulinaemia increases the cytokine content in essential organs after an endotoxin challenge in a porcine model.

BACKGROUND: Insulin has anti-inflammatory effects, as evaluated by its ability to reduce the plasma concentrations of cytokines. However, the inflammatory processing at the organ level is far less well established. The cytokine content in several organs after endotoxin (lipopolysaccharide, LPS) exposure and the effect of hyperinsulinaemia was examined. METHODS: Pigs (35-40 kg) were randomized into four groups, anaesthetized and mechanically ventilated for 570 min: group 1 (anaesthesia only; n = 10), group 2 (hyperinsulinaemic euglycaemic clamp, HEC; n = 9), group 3 (LPS; n = 10) and group 4 (LPS + HEC; n = 9). LPS was infused intravenously for 180 min (total dosage, 10 microg/kg). At the end of the study, i.e. 330 min after the termination of LPS or equivalent, cytokine mRNA and cytokine protein contents in the lungs, heart, liver, adipose tissue and spleen were measured. RESULTS: Hyperinsulinaemia led to increased interleukin-10 (IL-10) protein content in the heart and liver (by 40% and 28%, respectively) in comparison with normoinsulinaemic animals (P < 0.01 and P = 0.02, respectively), and increased tumour necrosis factor-alpha (TNF-alpha) protein content in the heart (P = 0.02). Animals exposed to LPS exhibited reduced TNF-alpha, IL-6 and IL-8 protein content in the heart (P = 0.02, P < 0.001 and P = 0.01, respectively). In the kidneys and adipose tissue, a particularly large cytokine protein content was observed. CONCLUSION: The findings strongly substantiate the role of insulin as an immune-modifying hormone at organ level during baseline and after an endotoxin challenge. Moreover, the kidneys and adipose tissue appear to be pivotal organs in terms of cytokine content shortly after endotoxin exposure, but the complexity remains to be clarified.

Renal effects of hypotensive anaesthesia in combination with acute normovolaemic haemodilution with hydroxyethyl starch 130/0.4 or isotonic saline.

BACKGROUND: Hypotensive anaesthesia (HA) and acute normovolaemic haemodilution (ANH) are used separately to decrease per-operative blood loss. Reducing blood viscosity by adding ANH to HA may appear profitable in a situation with lowered perfusion pressure and concern about organ ischemia. The aim of this study was to clarify the influence of HA in combination with ANH using crystalloid or colloid as replacement fluid on renal function. METHODS: Hypotensive anaesthesia was induced in 11 patients referred to major spine surgery using sevoflurane in combination with fentanyl/remifentanil. Acute normovolaemic haemodilution was carried out by drawing venous blood into standard blood bags and replacing it by isotonic saline 0.9% (Group S) or HES 130/0.4 (Group V). Renal function was evaluated before, during and up to 8 h after hypotension as the glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) by means of 51Cr-EDTA and 125I-Hippuran clearances. RESULTS: Lowering mean arterial blood pressure decreased GFR and ERPF in both groups. During hypotension ERPF was lower in Group S (n = 5) than Group V (n = 6). Renal function was normalized postoperatively. We found a positive but non-significant correlation between the relative GFR change and the duration of hypotension. CONCLUSION: In conclusion, our study demonstrated that renal function, assessed by GFR and ERPF, is transiently reduced during the combination of hypotensive anaesthesia and acute normovolaemic haemodilution. A colloid-based fluid regime (HES 130/0.4) used for haemodilution may preserve renal function to a greater extent than a crystalloid-based regime (0.9% saline).

Infusion of hypertonic saline (7.5% NaCl) causes minor immunological changes in normovolaemic women.

BACKGROUND: Haemorrhagic shock is treated effectively by infusion of hypertonic saline/colloid solutions. Furthermore, previous studies found hypertonicity to affect immune responses in animals and in human blood cell cultures. It is unknown, however, whether hypertonic saline infusion affects immune responses in humans. METHODS: In a randomized double-blind study, we infused 4 ml kg-1 of 7.5% NaCl or 0.9% NaCl over 10 min in 20 fasting women before hysterectomy. We collected peripheral blood at baseline, 30, and 120 min after start of the infusion and before surgery for the determination of leucocyte and differential count; lymphocyte subtypes; neutrophil chemotaxis; elastase concentration; and the cytokine's tumour necrosis factor-alpha (TNFalpha), interleukin (IL)-1beta, IL-6, IL-8, IL-1 receptor antagonist (IL-1ra), and IL-10. Phytohaemagglutinin (PHA)-induced lymphocyte proliferation and natural killer cell cytotoxicity were measured before and 120 min after infusion. RESULTS: Compared with normal saline, infusion of hypertonic saline temporarily increased the number of B cells in peripheral blood (P < 0.01); increased the concentration of plasma elastase, a marker of neutrophil degranulation (P < 0.05); and decreased the number of circulating neutrophils (P < 0.001). No other effects were detected in the measured immunological parameters. CONCLUSION: The immunological consequences of hypertonic saline infusion seem to be modest and are unlikely to cause any clinical effects, at least in normovolaemic women.

Plasma cytokines do not reflect expression of pro- and anti-inflammatory cytokine mRNA at organ level after cardiopulmonary bypass in neonatal pigs.

BACKGROUND: Plasma concentrations of inflammatory markers are increased in response to the trauma of cardiac surgery and cardiopulmonary bypass (CPB). It is, however, unknown whether the plasma cytokine levels and cytokine mRNA expression at organ level reflect each other. METHODS: Twenty-six piglets (17-19 days) were allocated to the sham-group (sternotomy only, n = 13) or to the CPB-group (sternotomy, 120 min CPB procedure with 60-min aortic cross-clamp, n = 13). The pigs were observed for 0.5 h or 4 h post-CPB. Plasma levels of IL-1beta, IL-6, IL-8 and IL-10 and mRNA expression of TNF-alpha, IL-1beta, IL-6, IL-8, IL-10 and iNOS in organs were registered with concomitant changes in oxygenation index (OI) and expiratory nitric oxide (NO). RESULTS: In pigs killed 0.5 h post-CPB there was a significant increase in IL-10 mRNA in the lungs and kidneys compared with the sham-group. IL-1beta mRNA was detectable in the kidneys and lungs of the CPB-pigs, while IL-6 mRNA was up regulated only in lungs. In pigs killed 4 h post-CPB a significantly higher IL-6 mRNA was found in heart tissue and a lower IL-10 mRNA was found in lungs of CPB pigs compared with the sham-group. There was a concomitant significant increase in OI and increased plasma IL-8 and IL-10 concentrations in the CPB-pigs compared with the sham-pigs. CONCLUSION: The cytokine mRNA expression pattern was very different for the pigs killed already 0.5 h after the CPB procedure compared with the pigs killed 4 h post-CPB. The plasma cytokine levels poorly reflected mRNA expression of the pro- and anti-inflammatory cytokines.

Lipid solubility- and concentration-dependent attenuation of in vitro natural killer cell cytotoxicity by local anesthetics.

BACKGROUND: Natural killer (NK) cells constitute an essential component of the innate immune system in the defence against infected and malignant cells. In this study the in vitro effect on NK cell activity of three different local anesthetics with different lipid solubility was investigated. METHODS: Venous blood from seven healthy volunteers was incubated with three amide local anesthetics with three different concentrations of lipid solubility: lidocaine 0.50, 1.00 and 2.00 mg/ml, ropivacaine 0.375, 0.75 and 1.50 mg/ml, and bupivacaine 0.25, 0.50 and 1.00 mg/ml. After 1 h of incubation, mononuclear cells were isolated and cryopreserved until tested for NK cell cytotoxicity in a 4-h 51Cr-release assay against K-562 target cells. Natural killer cell cytotoxicity of mononuclear cells incubated with isotonic saline was used as the control. RESULTS: A significant suppression in NK cell cytotoxicity was demonstrated for all three local anesthetic agents when the NK cell cytotoxicity was compared with the cytotoxicity estimated after incubation with the isotonic saline (P<0.004). Moreover a significant lipid solubility-dependent effect (P=0.0001) as well as an overall concentration-dependent effect (P<0.0001) on the NK cell cytotoxicity was found. CONCLUSION: The results of the present in vitro study suggest a negative association between the estimated NK cell cytotoxicity and the lipid solubility as well as the concentrations of the three local anesthetic agents tested.