Inotropes inhibit endothelial cell surface adhesion molecules induced by interleukin-1beta

The effects of sepsis on endothelium and clinical implications

ABSTRACT

Sepsis accounts for nearly 700 000 deaths in Europe annually and is caused by an overwhelming host response to infection resulting in organ failure. The endothelium is an active contributor to sepsis and as such represents a major target for therapy. During sepsis, endothelial cells amplify the immune response and activate the coagulation system. They are both a target and source of inflammation and serve as a link between local and systemic immune responses. In response to cytokines produced by immune cells, the endothelium expresses adhesion molecules and produces vasoactive compounds, inflammatory cytokines, and chemoattractants, thus switching from an anticoagulant to procoagulant state. These responses contribute to local control of infection, but systemic activation can lead to microvascular thrombosis, capillary permeability, hypotension, tissue hypoxia, and ultimately tissue damage. This review focuses on the role of the endothelium in leucocyte adhesion and transmigration as well as production of reactive oxygen and nitrogen species, microRNAs and cytokines, formation of signalling microparticles, and disseminated intravascular coagulation. We also discuss alterations in endothelial permeability and apoptosis. Finally, we review the diagnostic potential of endothelial markers and endothelial pathways as therapeutic targets for this devastating disease.

Effect of endotoxin, dobutamine and dopamine on muscle mitochondrial respiration in vitro

Introduction: Mitochondrial respiration is impaired during endotoxemia. While catecholamines are frequently used in sepsis, their effects on mitochondrial function are controversial. We assessed effects of dobutamine and dopamine endotoxin on isolated muscle mitochondria.

Materials and Methods : Sternocleidomastoid muscle mitochondria were isolated from six anesthetized pigs. Each sample was divided into six different groups. Three groups were incubated with endotoxin, three with vehicle. After 1 h, dopamine and dobutamine at final concentrations of 100 µM were added to the vehicle and endotoxin groups. After 2 h, state 3 and 4 respiration rates were determined for all mitochondrial complexes. Oxygen consumption was determined with a Clark-type electrode.

Results: Endotoxin increased glutamate-dependent state 4 respiration from 9.3 ± 3.6 to 31.9 ± 9.1 ( P = 0.001) without affecting state 3 respiration. This reduced the efficiency of mitochondrial respiration (RCR; state 3/state 4, 9.9 ± 1.9 versus 3.6 ± 0.6; P < 0.001). The other complexes were unaffected. Catecholamine partially restored the endotoxin-induced increase in complex I state 4 respiration rate (31.9 ± 9.1 versus 17.1 ± 6.4 and 20.1 ± 12.2) after dopamine and dobutamine, respectively ( P = 0.007), and enhanced the ADP:O ratio ( P = 0.033).

Conclusions: Dopamine and dobutamine enhanced the efficiency of mitochondrial respiration after short-term endotoxin exposure.

Immunomodulation of neutrophil–endothelial interaction by inotropes

OBJECTIVE

To evaluate the effect of the inotropes epinephrine, dopamine and dobutamine on expression of endothelial adhesion molecules and on neutrophil adhesion to endothelial cells under dynamic conditions.

METHODS

Endothelial cells were obtained by collagenase digestion of human umbilical cord veins.Endothelial monolayers were pre-incubated with one of the chosen inotropes, with or without butoxamine, and exposed to interleukin-1. The monolayers were then incubated with fluorescencelabelled anti-human monoclonal antibodies directed against the endothelial adhesion molecules ICAM-1, E-selectin or VCAM-1. Expression of endothelial adhesion molecules was analysed by flow cytometry after pre-incubation of endothelial monolayers with one of the chosen inotropes, with or without butoxamine, and after exposure to interleukin-1. To evaluate the neutrophil adherence, the endothelium was placed on a horizontal shaker-incubator and overlayered with neutrophils. Then, non-adherent neutrophils were removed, and cells were completely dissociated. Finally, neutrophils and endothelial cells were counted by flow cytometry.

RESULTS

The expression of E-selectin on endothelium following stimulation with interleukin-1 is attenuated by the inotropes dopamine or dobutamine, but not by epinephrine. The addition of butoxamine does not modify the expression of E-selectin following stimulation with interleukin-1 and pre-incubation with one of the chosen inotropes. The decrease in neutrophil adhesion to endothelium following stimulation with interleukin-1 and addition of inotropes is antagonised by the b-blocker butoxamine.

CONCLUSION

In contrast to the modulation of E-selectin expression on endothelium, the effect of inotropes on neutrophil adhesion to endothelium is regulated by the expression of adhesion molecules on PMNs and mediated by the b-adrenoceptor.

In vitro endothelial cell activation and inflammatory responses in end-stage heart failure

BACKGROUND

vascular endothelial cell activation and dysfunction are observed in patients with severe heart failure and may contribute to systemic manifestations of this syndrome. It remains unknown whether inflammatory activation of these cells occurs in these patients because of increased circulating proinflammatory mediators.

AIM

to determine whether the serum from patients with heart failure possesses a net proinflammatory bioactivity to active proinflammatory pathways in cultured endothelial cells.

METHODS

serum was obtained from stable patients with end-stage heart failure undergoing elective cardiac transplantation (Tx) and severely decompensated patients with heart failure requiring emergency left ventricular assist device (LVAD) implantation. Net proinflammatory bioactivity of serum was investigated by monitoring IkappaBalpha degradation and E-selectin expression in cultured human pulmonary artery endothelial cells (HPAEC) following incubation with serum samples. Serum cytokine concentrations were measured by ELISA and neutralizing antibodies were used to determine the role of specific factors in the observed bioactivity.

RESULT

serum from both patient groups induced HPAEC IkappaBalpha degradation. Low basal HPAEC E-selectin expression significantly increased following treatment with Tx but not LVAD serum. Serum tumor necrosis factor-alpha (TNF-alpha) and IL-10 concentrations were higher in patients with LVAD than those with Tx, and soluble TNF-alpha receptor expression was high in both groups. Neither TNF-alpha nor IL-10 blocking experiments altered either bioassay result.

CONCLUSION

activation of a specific profile of pro- and anti-inflammatory mediators is associated with heart failure resulting in HPAEC nuclear factor (NF)-kappaB activation. However, E-selectin expression is further regulated by unidentified factors. TNF-alpha is upregulated but appears to play no part in NFkappaB activation in these patients. These findings could have important therapeutic implications.

Effect of amrinone on mucosal permeability in experimental intestinal ischaemia/reperfusion injury

BACKGROUND

The preventive effect of amrinone on ischaemia/reperfusion (I/R) injury has been shown in the medical literature. The purpose of the present study was to investigate the preventive effect of amrinone on I/R injury of the small bowel of the rat.

METHODS

Thirty-two Wistar albino rats (140-180 g) were divided into four groups (n = 8). In all groups except the sham group the superior mesenteric artery was clamped for 30 min. At the beginning of reperfusion, 1 mL of 2405 Bq/mL 51Cr-ethylenediamine tetra-acetic acid (EDTA) was administered into the prepared ileal segment. Following 30 min of reperfusion, 1 mL of blood was obtained from the portal vein. After the rats were killed, the small intestine was removed for histopathological studies. A total of 5 mg/kg amrinone was administered to the rats in group 1 before ischaemia and in group 2 before reperfusion, whereas only saline was administered to the rats in the control group. Statistical analysis was carried out with Kruskal-Wallis and chi2 test, P < 0.01 was considered significant.

RESULTS

Both the blood 51Cr-EDTA measurements (mean +/- SD) and mucosal injury grades (MIG) were highest in the control group (3.95 +/- 0.71 c.p.m.; MIG, 3-5) followed by group 2 (0.50 +/- 0.35 c.p.m.; MIG, 1-3), group 1 (0.47 +/- 0.34 c.p.m. MIG, 0-3), and sham group (0.12 +/- 0.05 c.p.m.; MIG, 0). The difference between groups 1 and 2 and the control group were statistically significant (P < 0.01 for each comparison). The results of group 1 and 2 were similar statistically (P > 0.05).

CONCLUSIONS

Amrinone was found to be effective in preventing intestinal I/R injury.

The influence of desmopressin and vasopressors in the donor management on graft function following pancreas transplantation

INTRODUCTION

The use of desmopressin and vasopressors in cadaveric organ donors is considered a risk factor for graft dysfunction following pancreas transplantation by influencing the microcirculation. The aim of this study was to investigate the influence of these substances on early graft function.

PATIENTS AND METHODS

This single-center retrospective trial included 59 patients who underwent simultaneous or solitary pancreas transplantation. The corresponding donor charts were reviewed for the use of vasopressors and desmopressin. Impaired graft function was determined as graft thrombosis or as insulin-dependence for more then 3 days posttransplant. Daily amylase and lipase concentrations from abdominal drains were measured to quantify reperfusion pancreatitis and fistula formation.

RESULTS

Overall, pancreas thrombosis was observed in 4 of 59 (6.8%) recipients. There were no significant differences in thrombosis rate whether the donors received desmopressin (3/38 vs 1/21, P >.1) or the needed vasopressors (3/53 vs 1/9, P >.1). The number of patients who required insulin for more than 3 days posttransplant was comparable whether the donors received desmopressin (9/38 vs 4/21, P >.1), or vasopressors (9/46 vs 3/8, P >.1). At present all recipients with functioning pancreatic grafts (ie, 92.7%) are free of exogenous insulin therapy at 2 to 80 months posttransplant. The amylase/lipase concentrations of peritoneal fluid were independent of the administration of desmopressin or vasopressors in the donors.

CONCLUSION

In this study donor desmopressin and vasopressor administration did not influence graft function after pancreas transplantation.

Impact of donor dopamine on immediate graft function after kidney transplantation

Optimizing medical donor management may have a considerable impact on transplantation outcome. This study investigated the effect of donor dopamine on initial graft function in renal allograft recipients, involving 254 consecutive recipients of a cadaver kidney, aged 18-74 years, transplanted between 1990 and 2003. Immunosuppression was based on cyclosporine. Patients were grouped according to donor use of dopamine during intensive care. Delayed graft function (DGF), and serial creatinine concentrations were compared between the groups. Dopamine-treated and -untreated donors were very similar regarding hemodynamics and renal function. Delayed graft function occurred in 47/158 treated and 48/96 untreated kidneys (p = 0.001). Donor dopamine was associated with a more rapid decrease of s-creatinine, which became obvious on the first postoperative day. Of patients in the treated and untreated group, respectively, 81.9% and 65.8% reached a s-creatinine level less than 2 mg/dL during the first month (p = 0.005). Donor dopamine remained predictive of a normalized s-creatinine level [HR 1.71; 95% CI 1.22-2.41] after controlling for confounding factors by multivariate Cox regression. Donor dopamine is associated with improvements of initial graft function after kidney transplantation. The beneficial effect of dopamine is achievable without side-effects for the recipients, and correlates with superior long-term graft survival.

Modulation of chemokine production and expression of adhesion molecules in renal tubular epithelial and endothelial cells by catecholamines

BACKGROUND

The present study was conducted to investigate whether catecholamines influence the production of chemokines and adhesion molecules in proximal tubular epithelial cells (PTECs) and endothelial cells.

METHODS

PTECs and human umbilical vein endothelial cells (HUVECs) were stimulated with various concentrations of dopamine (DA), adrenaline (AD), or noradrenaline (NA), and the production of interleukin (IL)-8, ENA-78, and Gro-alpha was assessed by ELISA. The influence of catecholamine pretreatment on tumor necrosis factor (TNF)-alpha-mediated production of these chemokines and the expression of adhesion molecules was also tested.

RESULTS

In PTECs, DA inhibited the production of all three chemokines in a dose-dependent fashion. Although inhibition in ENA-78 and Gro-alpha production was also found in HUVECs, IL-8 production was up-regulated in these cells. Increased IL-8 secretion was predominantly observed at the apical site of the cells. In AD or NA stimulated cells, the production of Gro-alpha was increased in PTECs and decreased in HUVECs. Down-regulation in IL-8 production was also observed after AD but not after NA stimulation of both cell types. Interestingly, TNF-alpha-mediated up-regulation in intercellular adhesion molecule 1, vascular cell adhesion molecule (VCAM), and E-selectin was delayed in DA-pretreated HUVECs but not in PTECs. The influence of DA, but not AD or NA, on chemokine production was completely prevented by the addition of N-acetylcysteine.

CONCLUSIONS

This study demonstrates that catecholamines differentially influence chemokine production and indicates that DA may have anti-inflammatory properties because it delays the expression of adhesion molecules and inhibits the production of chemokines in PTECs and endothelial cells under basal and inflammatory conditions.

Frequent development of lupus anticoagulants in critically ill patients treated under intensive care conditions

OBJECTIVE

To investigate how often a prolongation of the activated partial thromboplastin time in critically ill patients is caused by lupus anticoagulants and to identify possible triggering events.

DESIGN

Prospective study.

SETTING

Internal medicine intensive care unit (University Hospital of Vienna, Vienna, Austria).

PATIENTS

Fifty-one critically ill patients without severe coagulopathy, hepatopathy, or anticoagulant treatment (35 male, 16 female, median age 60 yrs, range: 22-85 yrs).

INTERVENTIONS

All patients were screened daily for lupus anticoagulants with the activated partial thromboplastin time STA assay.

MEASUREMENTS AND MAIN RESULTS

Diluted Russell's viper venom time, plasma mixing studies, and confirmation assays were used to identify lupus anticoagulants at the time of an unexplained prolongation of the activated partial thromboplastin time. The influence of heparin was excluded by determination of thrombin clotting time and anti-Xa activity. In 27 of 51 patients (52.9 %) lupus anticoagulants were found after a median stay of 13 days. None of the patients had concomitant immune thrombocytopenia, hypoprothrombinemia, bleeding, or thromboembolic complications. Sepsis (p =.006) and/or catecholamine treatment (p =.002) were significantly associated with the development of lupus anticoagulants. Extracorporeal circulation, transfusion of blood products, or surgery did not increase this risk. Lupus anticoagulants resolved spontaneously in 63% of the patients after a median stay of 17 days.

CONCLUSIONS

Lupus anticoagulants are frequent in critically ill patients and associated with sepsis syndrome and/or catecholamine treatment. The prolonged activated partial thromboplastin time does not warrant the administration of coagulation factors or the cessation of anticoagulant therapy or prophylaxis, inasmuch as this phenomenon is not associated with bleeding or thromboembolic complications.

Modulation of chemokine production in lung microvascular endothelial cells by dopamine is mediated via an oxidative mechanism

Serum concentrations of catecholamines are high in patients with sepsis or acute respiratory distress syndrome (ARDS). Because chemokines mediate the recruitment of neutrophils into inflammatory sites, we addressed the question of whether dopamine (DA) is able to influence chemokine production in endothelial cells under basal and proinflammatory conditions. To this end, lung microvascular endothelial cells (LMVEC) were stimulated or not for 24 h with the bacterial toxins lipopolysaccharide (LPS) (1 microg/ml) or lipoteichonic acid (LTA) (10 microg/ml) in the presence or absence of various concentrations of DA (1-100 microg/ml). Whereas under basal and stimulatory conditions, the addition of DA to endothelial cells dose-dependently increased IL-8 production, the production of ENA-78 and Gro-alpha was significantly inhibited (P < 0.01). This effect could still be demonstrated when the cells were stimulated for up to 3 h with LPS before DA administration. Similar findings were detected for the mRNA expression of these chemokines. The influence of DA on chemokine production was not receptor mediated and could be prevented by antioxidants or radical scavengers. Moreover, addition of H(2)O(2) to endothelial cells gave results similar to those observed with DA stimulation, suggesting a pivotal role for reactive oxygen species in DA-mediated modulation of chemokine production in endothelial cells. Our data thus demonstrate that DA administration results in the induction of oxidative stress, with profound effects on endothelial chemokine production.

Serum concentration of adhesion molecules in patients with delayed ischaemic neurological deficit after aneurysmal subarachnoid haemorrhage: the immunoglobulin and selectin superfamilies

OBJECTIVES

Adhesion molecules are involved in the pathogenesis of cerebral ischaemia and may play a part in the pathophysiology of delayed ischaemic neurological deficit (DIND) after aneurysmal subarachnoid haemorrhage. It was hypothesised that after aneurysmal subarachnoid haemorrhage, adhesion molecules may play a part in the pathophysiology of DIND as reflected by significantly altered serum concentrations in patients with and without DIND.

METHODS

In a prospective study, mean serum concentrations of ICAM-1, VCAM-1, PECAM, and E, P, and L-selectin were compared between patients without (n=23) and with (n=13) DIND in patients with World Federation of Neurological Surgeons (WFNS) grades 1 or 2 subarachnoid haemorrhage. Serum was sampled from patients within 2 days of haemorrhage and on alternate days until discharge. Concentrations of adhesion molecules were measured by standard procedures using commercially available enzyme linked immunoabsorbent assays.

RESULTS

There were non-significant differences in serum concentrations of ICAM-1 (290.8 ng/ml v 238.4 ng/ml, p=0.0525), VCAM-1 (553.2 ng/ml v 425.8 ng/ml, p=0.053), and PECAM (22.0 ng/ml v 21.0 ng/ml, p=0.56) between patients without and with DIND respectively. The E-selectin concentration between the two patient groups (44.0 ng/ml v 37.4 ng/ml, p=0.33) was similar. The P-selectin concentration, however, was significantly higher in patients with DIND compared with those patients without DIND (149.5 ng/ml v 112.9 ng/ml, p=0.039). By contrast, serum L-selectin concentrations were significantly lower in patients with DIND (633.8 ng/ml v 897.9 ng/ml, p=0.013).

CONCLUSIONS

Of all the adhesion molecules examined in this study, P and L-selectin are involved in the pathophysiology of DIND after aneurysmal subarachnoid haemorrhage.

Effects of catecholamine application to brain-dead donors on graft survival in solid organ transplantation

BACKGROUND

In a recent single-center study, donor use of catecholamines was identified to reduce kidney allograft rejection. This study investigates the effects of donor employment of adrenergic agents on graft survival in a large data base, including liver and heart transplants.

METHODS

The study was based on the registry of the Eurotransplant International Foundation including 2415 kidney, 755 liver, and 720 heart transplants performed between January 1 and December 31, 1993. A total of 1742 donor record forms referring to the cadaveric donor activities in 1993 were systematically reviewed with regard to employment of adrenergic agents. Catecholamine use was simply coded dichotomously and divided into three strata according to zero, single, and combined application. Multivariate Cox regression including age, gender, cause of brain death, cold ischemia, HLA-mismatching, number of previous transplants, and urgency in liver transplants was applied for statistical analysis.

RESULTS

Donor employment of catecholamines was associated with increased 4-year graft survival after kidney transplantation (hazard ratio [HR], 0.85; 95% confidence interval [95% CI], 0.74-0.98). The benefit is conferred in a dose-dependent manner and compares in quantitative terms with prospective HLA matching on class I and class II antigens (HR, 0.90; 95% CI, 0.84-0.97). Use of norepinephrine was predictive of initial nonfunction after heart transplantation (HR, 1.66; 95% CI, 1.14-2.43), but did not compromise liver grafts (HR, 0.94; 95% CI, 0.67-1.32).

CONCLUSIONS

Optimizing the management of brain-dead organ donors, including the possibility of selective administration of adrenergic agents, may provide a major benefit on graft survival without adverse side effects for the recipients. Further investigation on best use of adrenergic drugs, optimum dosage, and duration is warranted.

Effect of low-dose milrinone on gastric intramucosal pH and systemic inflammation after hypothermic cardiopulmonary bypass

OBJECTIVE

To investigate the usefulness of low-dose milrinone on gastric intramucosal pH (pHi) and systemic inflammation in patients undergoing hypothermic cardiopulmonary bypass (CPB).

DESIGN

Prospective randomized study.

SETTING

University hospital.

PARTICIPANTS

Twenty patients scheduled for cardiac surgery.

INTERVENTIONS

Ten patients were administered a low dose of milrinone, 0.25 microg/kg/min, from the initiation of CPB to 1 hour after admission to the intensive care unit. The other patients were administered saline. Supplemental inotropes and intravenous fluid were given to obtain adequate mean arterial blood pressure and pulmonary artery occlusion pressure.

MEASUREMENTS AND RESULTS

Gastric pHi and carbon dioxide pressure (PCO2) were assessed by capnometric air tonometry. The difference between PCO2 and arterial carbon dioxide pressure (PaCO2), PCO2-gap, was also examined. Systemic inflammatory responses were evaluated by serum interleukin-6 and leukocyte counts. Hemodynamics, oxygen delivery index, and oxygen uptake index were monitored with catheters in the radial and pulmonary arteries (thermodilution). The hepatic venous blood flow and left ventricular flow were measured using transesophageal echocardiography. Milrinone prevented gastric intramucosal acidosis, detected as a decrease in pHi or an increase in PCO2-gap, without affecting hepatic venous blood flow. Increases in interleukin-6, leukocyte count, and oxygen uptake index, all of which developed after CPB, were significantly less in the milrinone group than in the control group.

CONCLUSION

These results suggest that in patients undergoing hypothermic CPB, supplemental low-dose milrinone prevents gastric intramucosal acidosis and increases in some markers of systemic inflammation.

Dopamine induces the expression of heme oxygenase-1 by human endothelial cells in vitro

BACKGROUND

In a retrospective study of the kidney transplantations performed at our institution, we found that the administration of dopamine (DA) to the organ donors resulted in a significant improvement of long-term organ survival of the retrieved kidneys. To study the mechanisms underlying the organ protection associated with the administration of DA prior to transplantation, we questioned whether DA induces the antioxidative enzyme heme oxygenase-1 (HO-1) in cultured endothelial cells.

METHODS

Human umbilical vein endothelial cells (HUVECs) in culture were incubated with varying concentrations of DA for different time periods. Cells were subsequently assessed for the expression of HO-1 by Western blot and semiquantitative reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS

The presence of DA resulted in a dose- and time-dependent up-regulation of HO-1 both on RNA and protein level, whereas HO-1 was barely detectable under basal conditions. RT-PCR indicated the increased presence of HO-1 messenger RNA after 2 hours of incubation with DA, which peaked after 24 hours. The induction of HO-1 antigen was detectable after eight hours, as visualized by Western blot analysis. The addition of the antioxidant agents ascorbic acid and N-acetyl-cysteine both lead to dose-dependent inhibition of DA-mediated HO-1 induction. DA-mediated up-regulation of HO-1 was not influenced by the addition of either the D2-receptor antagonist haloperidol or the D1-receptor antagonist SCH 23390.

CONCLUSION

We conclude that DA induces the expression of the protective enzyme HO-1 in cultured endothelial cells by an oxidative mechanism. These findings may explain the beneficial effect of DA administration to kidney donors and indicate the potential role of DA in organ preconditioning.

Influence of amrinone on intestinal villus blood flow during endotoxemia

PURPOSE

The objective of this study was to determine the effects of a continuous infusion of the phosphodiesterase (PDE) inhibitor amrinone on mucosal villus blood flow in a normotensive model of endotoxemia.

MATERIALS AND METHODS

Twenty-four anesthetized and ventilated rats underwent laparotomy, and an ileal portion was exteriorized and opened by an antimesenteric incision. The ileal segment was fixed on a plexiglass stage with the mucosal surface upward. Microcirculatory parameters were assessed by intravital videomicroscopy. The animals were randomly assigned to receive one of three treatments: infusion of Escherichia coli lipopolysaccharides (LPS, 2 mg/kg/h) without phosphodiesterase inhibitor pretreatment (LPS group); or infusion of LPS with amrinone pretreatment (40 microg/kg/min, start 30 minutes before LPS infusion) (amrinone group), or infusion of equivalent volumes of NaCl 0.9% (control group). Macrohemodynamic parameters (MAP, HR) and microhemodynamic parameters of ileal mucosa (mean diameter of central arterioles = D(A) and mean erythrocyte velocity within the arterioles = VE) were measured 30 minutes before and at 0, 60, and 120 minutes after induction of endotoxemia. Mucosal villus blood flow was calculated from D(A) and VE.

RESULTS

In this normotensive endotoxemia model, MAP remained stable in the control and the LPS group but significantly decreased in the amrinone group.The endotoxin-induced decrease of V(E) and D(A) of central arterioles of mucosal villi could be attenuated and prevented, respectively. Thus, the endotoxin-induced decrease of mucosal villus blood flow was diminished but not fully restored by amrinone infusion.

CONCLUSION

Our results indicate that amrinone during an early stage of sepsis is of limited value. It attenuates mucosal hypoperfusion but contributes to systemic hypotension.

Influence of amrinone on tissue oxygenation of jejunal mucosa during endotoxemia

BACKGROUND

The intestinal mucosa is the portion of the gut most susceptible to impaired perfusion and oxygen delivery. The phosphodiesterase (PDE) inhibitor amrinone has been proposed to improve oxygen delivery and tissue perfusion during sepsis. The objective of this study was to investigate the effects of amrinone on arterial oxygenation (Pao(2)) and tissue oxygenation (Ptio(2)) of jejunal mucosa during endotoxemia.

MATERIALS AND METHODS

Forty anesthetized and ventilated rats were laparotomized and a jejunal portion was exteriorized and fixed on a plexiglass stage. The jejunum was punctured and a Clark-type microcatheter Po(2) probe and a microthermocouple were placed on the mucosa to measure Ptio(2). The animals were randomly assigned to receive one of the four treatments: infusion of Escherichia coli lipopolysaccharides (LPS, 2 mg/kg/h) without amrinone pretreatment (LPS group); infusion of LPS with amrinone pretreatment (40 microg/kg/min, start 30 min before LPS infusion, amrinone + LPS group); no treatment with either amrinone or LPS (control group); treatment with amrinone without LPS infusion (amrinone group). Mean arterial pressure (MAP), heart rate (HR), Pao(2), and Ptio(2) were measured 30 min before and 0, 60, and 120 min after induction of endotoxemia.

RESULTS

MAP remained stable in the control and LPS groups. In the amrinone + LPS group MAP decreased within the first 30 min of amrinone infusion and decreased further during endotoxemia. Pao(2) remained stable in the control group and decreased in the LPS group. This endotoxin-induced decrease in Pao(2) was attenuated in the amrinone + LPS group. The mucosal Ptio(2) decreased in the LPS group but remained stable in both the control and amrinone + LPS groups.

CONCLUSIONS

Pretreatment with amrinone was able to diminish a decrease in Pao(2) during endotoxemia, indicating that pulmonary dysfunction was attenuated. Endotoxin-induced tissue hypoxia of the intestinal mucosa, however, could be fully prevented, indicating that an additional improvement in compromised tissue perfusion had occurred.

Donor catecholamine use reduces acute allograft rejection and improves graft survival after cadaveric renal transplantation

BACKGROUND

Epidemiological data implicate that renal transplants from living unrelated donors result in superior survival rates as compared with cadaveric grafts, despite a higher degree of human lymphocyte antigen (HLA) mismatching. We undertook a center-based case control study to identify donor-specific determinants affecting early outcome in cadaveric transplantation.

METHODS

The study database consisted of 152 consecutive cadaveric renal transplants performed at our center between June 1989 and September 1998. Of these, 24 patients received a retransplant. Donor kidneys were allocated on the basis of prospective HLA matching according to the Eurotransplant rules of organ sharing. Immunosuppressive therapy consisted of a cyclosporine-based triple-drug regimen. In 67 recipients, at least one acute rejection episode occurred during the first month after transplantation. They were taken as cases, and the remaining 85 patients were the controls. Stepwise logistic regression was done on donor-specific explanatory variables obtained from standardized Eurotransplant Necrokidney reports. In a secondary evaluation, the impact on graft survival in long-term follow-up was further measured by applying a Cox regression model. The mean follow-up of all transplant recipients was 3.8 years (SD 2.7 years).

RESULTS

Donor age [odds ratio (OR) 1.05; 95% CI, 1.02 to 1.08], traumatic brain injury as cause of death (OR 2.75; 95% CI, 1.16 to 6. 52), and mismatch on HLA-DR (OR 3.0; 95% CI, 1.47 to 6.12) were associated with an increased risk of acute rejection, whereas donor use of dopamine (OR 0.22; 95% CI, 0.09 to 0.51) and/or noradrenaline (OR 0.24; 95% CI, 0.10 to 0.60) independently resulted in a significant beneficial effect. In the multivariate Cox regression analysis, both donor treatment with dopamine (HR 0.44; 95% CI, 0.22 to 0.84) and noradrenaline (HR 0.30; 95% CI, 0.10 to 0.87) remained a significant predictor of superior graft survival in long-term follow-up.

CONCLUSIONS

Our data strongly suggest that the use of catecholamines in postmortal organ donors during intensive care results in immunomodulating effects and improves graft survival in long-term follow-up. These findings may at least partially be explained by down-regulating effects of adrenergic substances on the expression of adhesion molecules (VCAM, E-selectin) in the vessel walls of the graft.

Endothelial cell adhesion molecules in meningococcal disease

BACKGROUND

Endothelial damage is important in meningococcal disease. Cell adhesion molecules, including P selectin, E selectin, and intercellular cell adhesion molecule 1 (ICAM-1), are expressed by activated endothelium and then subsequently shed.

METHODS

ICAM-1, P selectin, and E selectin were measured on admission to hospital in children with meningococcal infections.

RESULTS

Concentrations of shed cell adhesion molecules are reported for 78 children. Eleven did not have meningococcal disease. Of the 67 with meningococcal disease, 40 had mild disease (Glasgow meningococcal septicaemia prognostic score (GMSPS) < 8) and 27 had severe disease (GMSPS > or = 8). E selectin and ICAM-1 values were higher in those with meningococcal disease. The E selectin values in those with severe disease were higher than in those with mild disease. P selectin concentrations were not altered in meningococcal disease, but those who died had lower concentrations.

CONCLUSIONS

Endothelial activation in meningococcal disease is reflected by shed ICAM-1 and E selectin concentrations.