Graft Neutrophil Sequestration and Concomitant Tissue Plasminogen Activator Release During Reperfusion in Clinical Kidney Transplantation.

BACKGROUND: Inflammation, coagulation, and fibrinolysis are tightly linked together. Reperfusion after transient ischemia activates both neutrophils, coagulation, and fibrinolysis. Experimental data suggest that tissue plasminogen activator (tPA) regulates renal neutrophil influx in kidney ischemia and reperfusion injury. METHODS: In 30 patients undergoing kidney transplantation, we measured renal neutrophil sequestration and tPA release from blood samples drawn from the supplying artery and renal vein early after reperfusion. tPA antigen levels were measured using a commercial enzyme-linked immunosorbent assay kit. For each parameter, transrenal difference (Δ) was calculated by subtracting the value of the arterial sample (ingoing blood) from the value of the venous sample (outgoing blood). RESULTS: Positive transrenal gradients of tPA antigen occurred at 1 minute [Δ = 14 (3-46) ng/mL, P < .01] and 5 minutes [Δ = 5 (-3 to 27) ng/mL, P < .01] after reperfusion. At 5 minutes after reperfusion, a negative transrenal gradient of neutrophils was observed [Δ = -0.17 (-1.45 to 0.24) x 10E9 cells/L, P < .001]. At 1 minute after reperfusion, neutrophil sequestration into the kidney (ie, negative transrenal neutrophil count) correlated significantly with tPA release from the kidney (ie, positive transrenal tPA concentration), (R = -0.513 and P = .006). CONCLUSIONS: The findings suggest a proinflammatory role for tPA in ischemia and reperfusion injury in human kidney transplantation.

Hepatic neutrophil activation during reperfusion may not contribute to initial graft function after short cold ischemia in human liver transplantation.

BACKGROUND: Experimental models of hepatic ischemia/reperfusion injury have implicated a pathophysiologic role for neutrophils in subsequent hepatocellular damage. In human liver transplantation, however, the effect of reperfusion-induced neutrophil activation on initial graft function is not clear. METHODS: In 38 patients undergoing liver transplantation, neutrophil CD11b and L-selectin expression, neutrophil count, and plasma lactoferrin levels were measured. To assess changes within the graft during initial reperfusion, samples of blood entering and leaving the graft were obtained simultaneously, and transhepatic ratio calculated (hepatic vein/portal vein; 1 denotes no change, <1 a decrease, and >1 an increase across the liver). Graft steatosis, postoperative liver function, and outcome were recorded. Associations between neutrophil activation markers and outcome measures were evaluated. RESULTS: Substantial hepatic neutrophil activation occurred during initial reperfusion, demonstrated by concomitant L-selectin shedding and CD11b upregulation (transhepatic ratios 0.9 [0.7-1.0]; 1.4 [0.9-1.9]; both P < .001; portal vs hepatic vein]. Simultaneously, hepatic neutrophil sequestration and lactoferrin release occurred (0.3 [0.2-0.5]; 1.7 [1.3-3.4]; both P < .001). Neither cold ischemic time (CIT; median 5 hours 36 minutes) nor hepatic neutrophil activation during reperfusion predicted early graft function, nor was there any association between CIT and neutrophil activation. CONCLUSIONS: Despite short CIT, extensive graft neutrophil activation and sequestration occurred. This, however, was not associated with impaired early graft function, suggesting short CIT may protect against severe neutrophil-mediated injury.

Transhepatic neutrophil and monocyte activation during clinical liver transplantation.

BACKGROUND: During experimental liver transplantation, neutrophil sequestration results in increased oxygen free radical production and correlates inversely with graft viability. Neutrophil activation in clinical liver transplantation is poorly understood. METHODS: We assessed leukocyte sequestration and transhepatic differences of neutrophil and monocyte CD11b expression, neutrophil free radical production, and plasma concentrations of interleukin 6 and interleukin 8 in nine patients during liver transplantation. RESULTS: Significant hepatic neutrophil sequestration occurred during initial graft rewarming with portal blood, after inferior vena cava declamping, and after hepatic artery declamping (all P<0.05). A positive transhepatic difference (i.e., outcoming - ingoing) in CD11b expression of neutrophils was observed after portal vein declamping (51+/-32 relative fluorescence unit [RFU]) and in CD11b expression of monocytes during initial graft rewarming (67+/-86 RFU, both P<0.05). A transcoronary increase in both unstimulated (74+/-80 RFU) and N-formyl-methionyl-leucylphenylalanine-stimulated (112+/-168 RFU) neutrophil free radical production took place after hepatic artery declamping (both P<0.05). A negative transcoronary difference of interleukin 6 occurred during initial graft rewarming (-192+/-176 pg/ml) and a positive difference of interleukin 8 occurred after hepatic artery declamping (17+/-23 pg/ml, both P<0.05). CONCLUSIONS: Hepatic sequestration and transhepatic activation of neutrophils, and hepatic production of interleukin 8 occur during clinical liver transplantation. A splanchnic influx of interleukin 6 occurs to the graft, possibly modulating neutrophil-mediated graft reperfusion injury.

Preoperative and postoperative response to inhaled nitric oxide.

The preoperative dose response to inhaled nitric oxide (NO) was compared with the need for and response to NO after cardiac surgery in patients with congenital heart defect and secondary pulmonary hypertension. In a preoperative vasodilator test with inhaled NO 20, 40 and 80 ppm and oxygen, mean pulmonary artery pressure (PAP) was at least 40 mmHg and/or the pulmonary vascular resistance index (PVRI) 4 Wood units. Preoperatively, NO 40 ppm and FiO2 0.9 reduced systolic pulmonary/systemic arterial pressure (PAPs/SAPs) from 0.89 (SD 0.10) to 0.80 (0.18) and pulmonary/systemic vascular resistance (PVR/SVR) from 0.26 (0.13) to 0.13 (0.08). Haemodynamic assessment was repeated in 11 patients postoperatively. NO treatment was started if PAPs/SAPs rose to 0.8 or the pulmonary oximetry fell below 40%. Postoperatively, eight of 11 patients, including 6 patients with Down's syndrome, needed NO. PAPs/SAPs decreased more than preoperatively: 48.5% vs 11.2, p = 0.0045. Pulmonary oximetry increased by 15.7%, p = 0.02. The degree of preoperative response to NO did not differ between the patients with postoperative pulmonary hypertension and the other children. Patients with early pulmonary hypertensive crisis (first 24 h; n = 6) had a higher PVRI (7.6 vs 4.4 Um2; p = 0.003) and PVR/SVR (0.34 VS 0.17; p = 0.02) preoperatively. Two patients died in pulmonary hypertensive crisis.

Nitecapone reduces cardiac neutrophil accumulation in clinical open heart surgery.

BACKGROUND: To study the effect of nitecapone, a novel antioxidant, on cardiac neutrophil activation during cardiopulmonary bypass in patients. METHODS: In a double-blind, placebo controlled trial, 30 male patients undergoing coronary artery bypass grafting were randomly assigned to control (crystalloid cardioplegia, n = 15) and nitecapone groups (cardioplegia supplemented with nitecapone, n = 15). Leukocyte differential counts, neutrophil and monocyte CD11b and L-selectin expressions and neutrophil hydrogen peroxide production were measured in blood samples parallelly obtained from the coronary sinus and aorta before cardiopulmonary bypass and at 1, 5, and 10 min after aortic declamping. Myocardial myeloperoxidase activity was analyzed in biopsies taken at 1, 5, and 10 min after declamping. RESULTS: Transcoronary neutrophil difference (i.e., aorta--sinus coronarius) at 1 min after aortic declamping was significantly lower in nitecapone-treated patients (0.41 [-0.42-0.98] x 10(9) cells/l) than in controls (0.68 [-0.28-2.47] x 10(9) cells/l; P = 0.032). At 5 min after aortic declamping, significant transcoronary reduction of neutrophil hydrogen peroxide production and CD11b expression were observed in controls but not in nitecapone patients. At 24 h postoperatively, left ventricular stroke volume was better in nitecapone-treated patients (94 [51-118] ml) than controls (66 [40-104] ml; P= 0.018). Data are median [range]. CONCLUSION: Nitecapone added to cardioplegia solution reduces cardiac neutrophil accumulation and transcoronary neutrophil activation during clinical cardiopulmonary bypass. Reflected by better left ventricular stroke volume, nitecapone treatment may be an additional way of reducing the deleterious effects of neutrophil activation during cardiopulmonary bypass.

Delayed impairment of cerebral oxygenation after deep hypothermic circulatory arrest in children.

BACKGROUND: Clinical studies of deep hypothermic circulatory arrest (DHCA) have focused only on the immediate postoperative period. However, experimental findings suggest impairment of cerebral oxygenation at 2 to 8 hours after reperfusion. METHODS: In 10 children who had DHCA for heart operations, transcerebral differences of hemoglobin oxygen saturation and plasma hypoxanthine, xanthine, and lactoferrin concentrations were measured in concurrently obtained cerebral venous, arterial, and mixed venous samples up to 10 hours postoperatively. RESULTS: Compared with preoperative levels (57% +/- 7%), cerebral venous oxygen saturation was not significantly reduced until 2 hours (44% +/- 6%) and 6 hours (42% +/- 5%) after DHCA (p < 0.05). A statistically significant transcerebral (ie, cerebral vein versus artery) concentration difference of hypoxanthine was observed at 30 minutes (3.6 +/- 0.9 micromol/L), 1 hour (3.4 +/- 1.1 micromol/L), and 2 hours (3.1 +/- 0.8 micromol/L) after DHCA but not preoperatively (0.4 +/- 0.2 micromol/L). A transcerebral concentration difference of lactoferrin occurred 30 minutes after DHCA (196 +/- 70 microg/mL) but not preoperatively (16 +/- 20 microg/mL). CONCLUSIONS: Cerebral venous oxygen saturation of hemoglobin decreased as late as 2 to 6 hours after DHCA, in association with impaired cerebral energy status. Neutrophil activation in the cerebral circulation occurred 30 minutes after reperfusion.

Circulating xanthine oxidase and neutrophil activation during human liver transplantation.

BACKGROUND & AIMS: Oxygen free radicals, generated by xanthine oxidase (XO) and activated leukocytes, are involved in reperfusion injury in experimental liver transplantation. The roles of XO and neutrophil activation during reperfusion in clinical liver transplantation were studied. METHODS: In 10 patients undergoing liver transplantation, we assessed plasma concentrations of circulating XO by enzyme-linked immunosorbent assay (ELISA), the purine metabolites hypoxanthine, xanthine, and urate by high-performance liquid chromatography, lactoferrin by ELISA, and malondialdehyde fluorometrically up to 48 hours postoperatively. RESULTS: During reperfusion after portal vein declamping, elevated plasma concentrations of XO (52.1 ng/mL [range, 8.0-440.1]), hypoxanthine (81.62 micromol/L [48.2-108.7]), xanthine (21.01 micromol/L [8.7-22.3]), and lactoferrin (532.6 ng/mL [370.4-1326.6]) were observed compared with the preoperative levels (0 ng/mL [0-12], 1.88 micromol/L [0.62-3.15], 0.95 micromol/L [0-0.41], and 164.3 ng/mL [73.7-334.1], respectively; all P < 0.05). No changes occurred in urate or malondialdehyde. After portal vein declamping, XO, hypoxanthine, and xanthine levels were substantially greater in the hepatic than portal vein (all P < 0.05). Marginal transhepatic differences occurred in lactoferrin. CONCLUSIONS: Reperfusion during liver transplantation is associated with liberation of xanthine oxidase, hypoxanthine, and xanthine from the liver into the circulation. During reperfusion, intravascular neutrophil activation takes place in the hepatic circulation.

Prolonged granulocyte activation, as well as hypoxanthine and free radical production after open heart surgery in children.

OBJECTIVE: To investigate granulocyte activation, as well as hypoxanthine and free radical production in children during the first day after cardiopulmonary bypass. DESIGN: A prospective study of pediatric patients undergoing either cardiac surgery with a cardiopulmonary bypass or thoracotomy and extracardiac vascular surgery not requiring a cardiopulmonary bypass. SETTING: Operative and intensive care units, Children's Hospital, University of Helsinki, Finland. PATIENTS: Seven consecutive patients undergoing elective correction of a ventricular septal defect and six patients undergoing extracardiac surgery for ligation of a patent ductus arteriosus or repair a coarctation of the aorta. MEASUREMENTS AND MAIN RESULTS: Plasma concentrations of myeloperoxidase (140-334 micrograms/l preoperatively, 460-1692 micrograms/l at 0.2 h after declamping, 471-1386 micrograms/l at 0.5 h after declamping) and lactoferrin (77-258 micrograms/l preoperatively, 533-1783 at 0.2 h, 404-1482 micrograms/l at 0.5 h) as markers of granulocyte activation, and hypoxanthine (0-5.7 mumol/l preoperatively, 4.3-17.0 mumol/l at 0.2 h, 6.5-17.9 mumol/l at 0.5 h) increased in a biphasic manner at 0.2-0.5 h and 6-10 h postoperatively (all p < 0.05). Expired ethane, as an index of free radical activity, increased at 10 h postoperatively (36-119 pmol/kg per min preoperatively, 72-152 pmol/kg per min, p < 0.005). CONCLUSION: Granulocyte activation, and hypoxanthine and free radical production occur at least 10 h after cardiopulmonary bypass. In children undergoing open heart surgery, attempts to reduce free radical activity should be extended to the postoperative period.

Regional generation of free oxygen radicals during cardiopulmonary bypass in children.

Studies on free radical generation during cardiopulmonary bypass have focused mainly on the heart and the lungs. However, low pumping pressure, nonpulsatile perfusion, and hypothermia affect the entire circulation, resulting in decreased splanchnic blood flow, increased intestinal permeability, and endotoxemia. To evaluate regional phenomena, we studied 16 children undergoing cardiopulmonary bypass. Free radical production, granulocyte activation, and hypoxanthine metabolism were assessed separately in the circulations drained by the inferior and superior venae cavae, as well as in the oxygenator. Three minutes after the onset of cardiopulmonary bypass, significant gradients between the inferior vena cava and the arterial line of the oxygenator existed in malondialdehyde (+0.60 +/- 0.12 mumol/L, lactoferrin (+18.21 +/- 7.65 micrograms/L), myeloperoxidase (+53.75 +/- 16.50 micrograms/L), hypoxanthine (-0.62 +/- 0.15 mumol/L), and urate (+8.87 +/- 4.03 mumol/L). These gradients decreased in parallel with decreasing body temperature. Except for a transient gradient in malondialdehyde at 3 minutes after the onset of cardiopulmonary bypass (+0.23 +/- 0.08 mumol/L), no changes were detected between the superior vena cava and the arterial line. In the oxygenator, granulocyte activation was observed only after aortic declamping. We conclude that during cardiopulmonary bypass, significant free radical generation, granulocyte activation, hypoxanthine elimination, and urate production take place in the region drained by the inferior vena cava. In the oxygenator, granulocyte activation occurs only after aortic declamping.