Blockade of prostaglandin production increases cachectin synthesis and prevents depression of macrophage functions after hemorrhagic shock.

Although hemorrhage severely depresses macrophage functions, it is not known whether the increased TNF-alpha or PGE2 production is responsible for it. To study this C3H/HeN mice were bled to mean blood pressure of 35 mmHg for 60 minutes, resuscitated, and treated with either ibuprofen (1.0 mg/kg body weight) or vehicle (saline). Hemorrhage increased plasma prostaglandin E2 (PGE2) levels by 151.7% +/- 40.0% (p less than 0.05) and significantly decreased peritoneal macrophage (pM phi) antigen presentation (AP) by 60.5% +/- 7.3%, Ia expression by 52.3% +/- 7.6%, and interleukin-1 (IL-1) synthesis by 60.5% +/- 12.3% compared to shams. However ibuprofen treatment reduced PGE2 plasma levels by 61.3% +/- 12.1% and significantly increased AP (+237.0% +/- 95.3%), Ia expression (+72.8% +/- 27.5%), IL-1 synthesis (+235.7% +/- 134.7%), and cachectin synthesis (+485.8% +/- 209.0%) compared to vehicle-treated animals. These results indicate that prostaglandins but not cachectin are involved in the suppression of pM phi functions following hemorrhage because blockade of prostaglandin synthesis improved depressed macrophage functions despite enhanced cachectin synthesis.     

The complex pattern of cytokines in sepsis. Association between prostaglandins, cachectin, and interleukins.

Although the cytokines tumor necrosis factor (TNF), interleukin-1 (IL-1), and interleukin-6 (IL-6) are important mediators of hemodynamic, metabolic, and immunologic alterations in the host during sepsis, it is not known whether there is any association between the release of these cytokines and prostanoids during sepsis. Sepsis induced by cecal ligation and puncture in rats led to a persistent elevation (p less than 0.05) of plasma TNF until 10 hours, steadily increasing (p less than 0.05) IL-1 plasma levels, and enhanced (p less than 0.05) IL-6 plasma levels at all time points compared to the sham group. Prostaglandin E2 plasma levels were elevated (p less than 0.05) at 5 hours (153 +/- 29 pg/mL; control: 47 +/- 11 pg/mL) and 10 hours (96 +/- 16 pg/mL; control: 21 +/- 5 pg/mL). Prostaglandin E2 production by splenic macrophages (sM phi) from septic animals was increased (p less than 0.05) at 5 hours (9.1 +/- 2.2 ng/mL) and 10 hours (5.6 +/- 1.5 ng/mL) compared to controls (3.3 +/- 0.3 ng/mL at 5 hours; 1.3 +/- 1.3 ng/mL at 10 hours). Incubation of sM phi from septic animals with ibuprofen enhanced (p less than 0.05) IL-1 and TNF synthesis, while IL-6 production was reduced (p less than 0.05). These results indicate that the alterations in prostanoid release and elevated plasma prostanoids may regulate the release and consequently the circulating levels of cytokines during sepsis.     

Beneficial effect of enhanced macrophage function in the trauma patient.

Host immunosuppression after trauma contributes to septic morbidity. The macrophage is a key element in the host immune response. This study evaluated glucan, a macrophage stimulant, in a prospective, randomized, double-blind study of 38 trauma patients undergoing surgery. Glucan (21 patients), 50 mg/m2, or placebo (17 patients) was given intravenously daily for 7 days. Delayed hypersensitivity skin testing was performed on days 1 and 7 after trauma. Serum interleukin-1 (IL-1) and tumor necrosis factor (TNF) were assayed after trauma. While the total mortality rate was significantly less in the glucan group (0% versus 29%) (p less than 0.05), the mortality rate from sepsis was not statistically different (0% versus 17.6%). Glucan therapy significantly decreased septic morbidity (9.5% versus 49%; p less than 0.05). Serum IL-1 had a greater increase in glucan patients on day 3 after trauma (143.4 +/- 19.3% versus 78.6 +/- 11.7%; p less than 0.05), but there was no difference thereafter. Serum TNF did not vary between groups. Early increase in IL-1 correlated with subsequent skin test conversion to positive. Neither serum IL-1 nor TNF was a reliable indicator of future sepsis. Further clinical trials are indicated to evaluate biologic response modifiers that activate macrophages in the trauma patient.     

Ibuprofen restores cellular immunity and decreases susceptibility to sepsis following hemorrhage.

Although hemorrhage depresses splenocyte (SPL) functions and increases susceptibility to sepsis, it is not known whether increased tumor necrosis factor (TNF) or prostaglandin (PG) production are responsible for it. To study this, mice (C3H/HeN) were bled to a mean blood pressure of 35 mm Hg, maintained at that pressure for 60 min, resuscitated, and treated with ibuprofen (1.0 mg/kg body weight) or vehicle (saline). Hemorrhage reduced (P less than 0.05) SPL proliferation by 60%, SPL release of interleukin-2 (IL-2) by 47%, interferon-gamma (IFN-gamma) by 67%, TNF by 54%, and interleukin-6 (IL-6) by 46% compared to sham. In addition, splenic macrophage (sM phi) release of interleukin-1 (IL-1) and TNF was decreased by 58 and 67% (P less than 0.05), respectively. However, ibuprofen treatment increased (P less than 0.05) SPL proliferation, lymphokine (IL-2, IFN-gamma, and IL-6) synthesis, and IL-1 release by sM phi compared to hemorrhage alone. Furthermore, ibuprofen enhanced the release of TNF by SPL (+175%, P less than 0.05) and sM phi (+68%) compared to the vehicle group. Ibuprofen also decreased (P = 0.011) the susceptibility to sepsis following hemorrhage. These results indicate that PGs are involved in hemorrhage-induced suppression of cellular immunity and in the increased mortality of such animals following a septic challenge.     

Mechanism of the beneficial effects of ATP-MgCl2 following trauma-hemorrhage and resuscitation: downregulation of inflammatory cytokine (TNF, IL-6) release.

Although ATP-MgCl2 improves hepatocellular function in a nonheparinized model of trauma-hemorrhage and crystalloid resuscitation, it remains unknown whether the beneficial effects of this agent are due to downregulation of the release of the inflammatory cytokines, tumor necrosis factor (TNF), and interleukin-6 (IL-6) under those conditions. To study this, rats underwent a 5-cm laparotomy (i.e., trauma induced) and were bled to and maintained at a mean arterial pressure of 40 mm Hg until 40% of maximum bleedout volume was returned in the form of Ringer's lactate (RL). The animals were then resuscitated with four times the volume of shed blood with RL over 60 min. ATP-MgCl2 (50 mumoles/kg body weight each) or an equivalent volume of normal saline was infused intravenously for 95 min. This infusion was started during the last 15 min of RL resuscitation. Plasma levels of TNF and IL-6 were measured at 1.5 hr after the completion of resuscitation by cytokine-dependent cellular assays. Hepatic blood flow was determined by in vivo indocyanine green clearance (corrected by hepatic extraction ratio for indocyanine green), radioactive microspheres, and [3H]-galactose clearance techniques. The results indicate that the levels of circulating TNF and IL-6 increased significantly in the hemorrhaged-resuscitated animals. ATP-MgCl2 treatment, however, markedly decreased the synthesis and/or release of these cytokines to levels similar to the sham group. The markedly decreased hepatic blood flow (as determined by three different methods) and hepatic extraction ratio for indocyanine green were also restored by ATP-MgCl2 treatment.(ABSTRACT TRUNCATED AT 250 WORDS)     

Decreased IL-6 secretion by fibroblasts following repeated doses of TNF alpha or IL-1 alpha: post-transcriptional gene regulation

Tumor necrosis factor-alpha (TNF alpha) and interleukin-1 alpha (IL-1 alpha) are pluripotent cytokines mediating the host response to sepsis, injury, and cancer. Animals can be protected from the lethal effects of TNF alpha by repeated administration of sublethal doses, but the mechanism of this effect is not known. Human foreskin fibroblasts (FS4 cells), which rapidly elaborate interleukin-6 (IL-6) when stimulated with TNF alpha or IL-1 alpha, were grown in culture as confluent monolayers and their secretion of IL-6 was quantitated using the murine B9-hybridoma bioassay against an external reference of human recombinant IL-6 (Genetics Institute). When FS4 cells were incubated with human recombinant TNF alpha (50 ng/ml; Cetus) or recombinant IL-1 alpha (30 pg/ml; Genzyme) a rapid increase in IL-6 production was measured over control, rising to IL-6 levels of 71.7 +/- 5.9 units/ml with TNF alpha and 54.0 +/- 1.2 units/ml with IL-1 alpha after 7.5 hr incubation. FS4 cells which were exposed to cytokine, rinsed, and then reexposed to cytokine 24 hr later produced significantly less IL-6 [38.1 +/- 2.8 units/ml with second exposure to TNF alpha (P less than 0.05), and 18.3 +/- 1.9 units/ml with second exposure to IL-1 alpha (P less than 0.01)]. Successive daily exposure to TNF alpha or IL-1 alpha caused a further stepwise diminution of IL-6 secretion.(ABSTRACT TRUNCATED AT 250 WORDS)     

Modulation of interleukin-6 by beta2-adrenoceptor in endotoxin-stimulated renal macrophage cells.

BACKGROUND: Activation of the cAMP signaling pathway by means of beta2-adrenoceptor agonists has been shown to up-regulate interleukin-6 (IL-6) gene expression and to stimulate IL-6 production in macrophage cells. However, whether beta2-adrenoceptor activation can also modify the rate of IL-6 production in macrophage cells activated by the bacterial endotoxins has not yet been determined. Using renal resident macrophage cells treated with endotoxin, lipopolysaccharide (LPS), and beta2-adrenoceptor agonist, terbutaline, we investigated the role of cAMP pathway, tumor necrosis factor (TNF)-alpha and mitogen-activated protein kinase (MAPK) pathway (p42/p44) in regulating IL-6 production. METHODS: IL-6 protein, mRNA, and promoter activity were measured in these cells exposed to LPS (1 microg/ml) and/or terbutaline (10(-9) to 10(-6) M). Furthermore, the time course effects of terbutaline on cAMP, MAPK (p42/p44), and TNF-alpha release were evaluated in the cells. RESULTS: Terbutaline at high concentrations (10(-6) M) significantly up-regulated IL-6 by approximately 25% (P<0.05), whereas at a lower concentration (10(-8) M), it down-regulated IL-6 production by 42% (P<0.05). Terbutaline (10(-8) and 10(-6) M) caused a concentration- and time-dependent stimulation of cAMP (P<0.05) and TNF production (P<0.05) and a time-dependent decrease in MAPK activity (P<0.05). Following the addition of a cAMP inhibitor, IL-6 promoter activity was correlated with TNF-alpha levels and MAPK activity. CONCLUSIONS: A biphasic effect of beta2-adrenoceptor agonist on IL-6 production in renal resident macrophage cells became apparent when LPS was exposed to the cells. The terbutaline-induced down-regulation of IL-6 gene production was mediated by an inhibitory effect of terbutaline on TNF-alpha, which was exerted through the MAPK and cAMP pathways, whereas the up-regulation appeared to be due to a direct action of intracellular cAMP.     

Cytokine regulation of intestinal glutamine utilization.

The effects of cytokines on intestinal glutamine metabolism were studied to gain further insight into the regulation of altered glutamine metabolism that occurs during severe infection. One hundred thirteen adult rats were given a single dose of interleukin-1 (IL-1, 50 micrograms/kg), tumor necrosis factor (TNF, 50 micrograms/kg or 150 micrograms/kg), or saline (controls), and flux studies were performed 4 or 12 hours later. Intestinal blood flow was not different between control and cytokine-treated animals at either time point. At the 4-hour time point, arterial glutamine fell by 16% to 21% in the cytokine-treated animals (p less than 0.05); at the 12-hour time point, the arterial glutamine concentration had returned to normal. Intestinal glutamine extraction decreased in the animals treated with IL-1 at both time points (4 hours: 13% +/- 1.3% in IL-1 versus 20% +/- 1.6% in controls, p less than 0.05; and 12 hours: 9% +/- 2% in IL-1 versus 17% +/- 2% in controls, p less than 0.05). Consequently, net intestinal glutamine uptake fell in the animals treated with IL-1 at both time points (p less than 0.05). Similarly, the activity of mucosal glutaminase, the principal enzyme of glutamine hydrolysis in the gut, fell by 50% in the 4-hour study (6.1 +/- 0.6 mumol/h/mg protein in IL-1 versus 9.6 +/- 0.8 mumol/h/mg protein in controls, p less than 0.01) and by 40% in the 12-hour study (5.4 +/- 0.5 mumol/h/mg protein in IL-1 versus 8.8 +/- 0.4 mumol/h/mg protein in controls, p less than 0.05). Concomitant with the aforementioned decrease in gut glutamine metabolism was a 25% incidence of positive blood cultures for gram-negative organisms in IL-1 treated rats studied at the 12-hour time point (p = 0.05 versus controls). In the doses administered and at the time points studied, TNF had no effects on the parameters of gut glutamine metabolism examined. The results indicate that IL-1 is a potential mediator of the alterations in gut glutamine metabolism observed in sepsis and endotoxemia.     

Impaired mitogen-activated protein kinase activation and altered cytokine secretion in endotoxin-tolerant human monocytes

BACKGROUND: Dysregulation of monocyte/macrophage cytokine production after exposure to multiple inflammatory stimuli may contribute to multiple organ failure and sepsis. Endotoxin (lipopolysaccharide [LPS]) activation of murine macrophage results in the phosphorylation of kinases in the mitogen-activated protein kinase cascade. Pretreatment of murine macrophages with LPS induces LPS-tolerance, with inhibition of LPS-stimulated activation of kinases (ERK1/2 and p38) and diminished release of tumor necrosis factor (TNF). We sought to determine whether similar alterations in LPS-dependent signal transduction are present in LPS-tolerant human peripheral blood monocytes. METHODS: Human peripheral blood monocytes from healthy volunteer donors (n = 12) were incubated in RPMI 1640 culture medium +/- 10 ng/mL of LPS for 18 hours, then stimulated with 0 to 1,000 ng/mL of LPS. Supernatant TNF and interleukin-1 (IL-1) levels were measured after 5 hours by enzyme-linked immunosorbent assay. Activation of the p42/p44 kinases (ERK1/2) was measured 15 minutes after LPS with monoclonal antibodies to diphosphorylated (active) ERK1/2 using novel flow cytometric methods. RESULTS: LPS-tolerant (10 ng/mL LPS pretreatment) human monocytes had significant inhibition of LPS-stimulated TNF secretion but augmented IL-1 release (p < 0.05). Nontolerant human monocytes had a dramatic increase in the percentage of ERK1/2-positive cells in response to an initial stimulation with LPS. This did not occur in the LPS-tolerant cells. Phorbol-12-myristate-13 acetate restored ERK1/2 activation in LPS-tolerant human monocytes. CONCLUSION: LPS-tolerance in human monocytes is associated with inhibition of LPS-stimulated TNF secretion, augmented release of IL-1, and defective activation of mitogen-activated protein kinase cascade (ERK1/2). These results suggest a method of identifying LPS-tolerance and monocyte dysfunction in patients with sepsis.     

Inhibition of macrophage-activating cytokines is beneficial in the acute septic response.

Interferon-gamma and other cytokines enhance macrophage (M phi) antimicrobial function and have been considered for therapeutic use in sepsis. Systemic sequelae of macrophage activation, however, are unclear. This study examined the effects of M phi activating cytokines (interferon-gamma [IFN-gamma] and interleukin-4 [IL-4]) and monoclonal antibodies directed against these cytokines in modulating the acute septic response. CFW/Swiss Webster mice (n = 345) received endotoxin (lipopolysaccharide [LPS]: 60 mg/kg body weight intraperitoneally) and were randomized to five treatment groups: IFN-gamma (10(4) units), IL-4 (10(4) units), IgG1 isotype antibody (TRFK5: 200 micrograms), anti-IFN-gamma (200 micrograms), or anti-IL-4 (200 micrograms) monoclonal antibodies (MAbs) given simultaneously or 2 hours after LPS. Animals were divided into two groups and studied for mortality or measurement of peritoneal M phi superoxide anion release (O2-), tumor necrosis factor (TNF), and IL-6 production 6 hours after administration of LPS +/- experimental regimens. Serum TNF and IL-6 also were assessed at 2 and 4 hours after LPS, respectively. Administration of LPS resulted in a 27% survival compared with 10% in the IFN-gamma and 13% in the IL-4 groups. Treatment with anti-IFN-gamma offered protection against LPS lethality (93%-100% survival, p less than 0.001 vs. other groups) when given either simultaneously or 2 hours after LPS. Anti-IFN-gamma also significantly decreased PM phi O-2 and TNF release. Thus anti-IFN-gamma may have an important role in the modulation of the acute septic response.     

Systemic acute-phase response after laparoscopic and open cholecystectomy

BACKGROUND: Cytokines are the main mediators of inflammation and the response to trauma. The purpose of this study was to compare variations in cytokine levels following laparoscopic cholecystectomy (LC) and mini-laparotomy cholecystectomy (OC), since these two types of operations were considered to be a unique model for examining the role of local tissue injury in postoperative inflammatory reactions. METHODS: A total of 40 patients were studied. Eighteen of them underwent LC; the remaining 22 were operated on using the open technique. Systemic concentrations of interleukin-6 (IL-6), interleukin-1 (IL-1), tumor necrosis factor (TNF), and C-reactive protein (CRP) were measured before and after the operation. In addition, we compared pre- and postoperative white blood cell (WBC) counts, postoperative body temperature, and length of postoperative hospitalization. RESULTS: There was no difference between the two groups in IL-1 and TNF response. The rise in plasma IL-6 levels (18.86 +/- 9.61 vs 5.00 +/- 0.0 pg/ml, p < 0.0001) and CRP (8.40 +/- 5.81 vs 1.43 +/- 1.30 mg/dl, p < 0.001) were more marked after open cholecystectomy than after the laparoscopic procedure. There was no correlation between serum CRP concentrations and the other postoperative parameters. CONCLUSION: The magnitude of the acute-phase response was less pronounced following laparoscopic cholecystectomy, consistent with a reduction in tissue trauma.     

Changes in production of interleukin-1 and interleukin-2 associated with obstructive jaundice and biliary drainage in patients with gastrointestinal cancer

Increased susceptibility to infection in patients with obstructive jaundice has been well documented in vitro and in vivo. Nevertheless, an underlying mechanism for immunocompromise in these patients has not been identified. This study was undertaken to evaluate the production of two important immunoregulatory molecules, interleukin-1 (IL-1) and interleukin-2 (IL-2), by peripheral blood mononuclear cells in cancer patients with obstructive jaundice before and after percutaneous transhepatic biliary drainage (PTBD). After decompression with PTBD, IL-1 and IL-2 production was significantly increased (IL-1: from 7.9 +/- 4.9 to 13.9 +/- 4.9 U/ml, p less than 0.05; IL-2: from 8.8 +/- 4.9 to 14.1 +/- 6.5 U/ml, p less than 0.05). There was a positive correlation between IL-1 and IL-2 production (r = 0.424, p less than 0.05). The production of both interleukins correlated negatively with serum total bilirubin level (IL-1 r = -0.478, p less than 0.05; IL-2: r = -0.482, p less than 0.05) and positively with high-density lipoprotein cholesterol in serum (IL-1: r = 0.505, p less than 0.01; IL-2: r = 0.494, p less than 0.05). IL-2 production also correlated positively with serum albumin levels (r = 0.511, p less than 0.01). These results suggest that hyperbilirubinemia and abnormal lipid metabolism may be associated with impaired interleukin production, which may result in an increased susceptibility to infection during obstructive jaundice.     

Mechanism of the beneficial effects of pentoxifylline on hepatocellular function after trauma hemorrhage and resuscitation.

BACKGROUND. The purpose of this study was to determine whether pentoxifylline administration restores the depressed hepatocellular function after trauma hemorrhage and crystalloid resuscitation and, if so, whether this is the result of the down-regulation of inflammatory cytokines, tumor necrosis factor (TNF) and interleukin-6 (IL-6). METHODS. After laparotomy rats were bled to and maintained at a mean arterial pressure of 40 mm Hg until 40% of maximum shed blood volume was returned in the form of Ringer's lactate. They were then resuscitated with Ringer's lactate to four times the shed blood volume. Pentoxifylline (50 mg/kg body weight) or saline solution was infused intravenously for 95 minutes during and after resuscitation. One and a half hours and 4 hours after resuscitation, hepatocellular function (maximal velocity [Vmax] and the efficiency of the active transport [Km] of indocyanine green clearance) and plasma. TNF and IL-6 levels were determined with in vivo hemoreflectometer and cellular assays, respectively. RESULTS. Circulating TNF and IL-6 levels increased significantly after hemorrhage and resuscitation. Pentoxifylline treatment, however, markedly decreased the levels of these cytokines, and the values were similar to those of sham rats. The decreased Vmax and Km values were also restored by pentoxifylline treatment. Moreover, there was a significant correlation between Vmax and TNF or IL-6 levels. CONCLUSIONS. The down-regulation of inflammatory cytokines by pentoxifylline may be the mechanism by which this agent restores the depressed hepatocellular function after trauma hemorrhage and resuscitation.     

Blood mononuclear cell production of IL-1 and IL-2 following moderate surgical trauma

The in vitro interleukin-1 (IL-1) and interleukin-2 (IL-2) production and IL-2 receptor (IL-2-R) expression by peripheral blood mononuclear (PBM) cells were examined in patients undergoing elective cholecystectomy. The IL-1 production by monocytes stimulated with a lipopolysaccharide (LPS) did not change on day +1 but increased by 57.5% on day +3 (p less than 0.05) after surgery, and was normalized on days +5 and +7. The IL-1 production by PBM cells stimulated by LPS increased by 97.6% on day +1 (p less than 0.05) and 109.5% on day +3 (p less than 0.05) after surgery, and became normalized on days +5 and +7. The IL-2 level in PBM cell supernatants stimulated with phytohemagglutinin (PHA) decreased by 45.2% on day +1 (p less than 0.05), 33.3% on day +3 (p less than 0.05), 32.3% on day +5 (p less than 0.05) and returned to the preoperative values on day +7. The IL-2-R expression on PHA-stimulated lymphocytes increased from 60.4 +/- 4.8% preoperatively to 67.2 +/- 1.9% on day +1 (p less than 0.05) but was again within the preoperative values on days +3, +5 and +7. In order to detect the described changes, stimulation with PHA had to be used. This indicates that simple surgical trauma produces subthreshold activation of blood immune cells. The cells enter the 'response alert' stage which can be measured after stimulation with lectins.(ABSTRACT TRUNCATED AT 250 WORDS)     

Immunoprotective effect of a calcium channel blocker on macrophage antigen presentation function, major histocompatability class II antigen expression, and interleukin-1 synthesis after hemorrhage

Hemorrhage induces a severe suppression of the immune system resulting in increased susceptibility to sepsis. Although studies indicate beneficial effects of calcium channel blockers on cell and organ functions after low-flow conditions, it remains unknown whether such agents have any effects on different immune responses after hemorrhage. To study this, C3H/HeN mice were bled to a mean blood pressure of 35 mm Hg and were maintained for 60 minutes, followed by resuscitation with their own shed blood and adequate fluid. The mice received either the water-soluble calcium channel blocker diltiazem (400 or 2400 micrograms/kg body weight) or saline solution (vehicle). Peritoneal macrophages were obtained by lavage 24 hours later. Antigen presentation was measured by coculturing peritoneal macrophages with the D10.G4.1 helper T-lymphocyte clone. Immune associated antigen (Ia) expression was determined by direct immunofluorescence. Interleukin (IL)-1, 6, and tumor necrosis factor-alpha (TNF) levels in peritoneal macrophage supernatants were measured by use of cytokine-specific cellular assays. Hemorrhage caused a significant decrease in peritoneal macrophage antigen presentation function, Ia expression, and IL-1 and IL-6 synthesis in the vehicle-treated group, whereas TNF levels were increased. However, both doses of diltiazem significantly improved peritoneal macrophage antigen presentation, Ia expression, and IL-1 synthesis. IL-6 synthesis was only increased with high doses of diltiazem, whereas both diltiazem doses decreased TNF production. These results indicate that the calcium channel blocker diltiazem can markedly improve macrophage functions after hemorrhage. The use of diltiazem might offer a new therapeutic modality in the treatment of immunosuppression and in decreasing the susceptibility to sepsis after hemorrhagic shock.     

Do cytokines play a role in skeletal muscle ischemia and reperfusion?

Cytokines, interleukin-1 (IL-1) and tumor necrosis factor (TNF) are known to mediate host cell response to sepsis, trauma, and myocardial ischemia. We have previously found increased levels of IL-1 in the venous effluent during the reperfusion phase of skeletal muscle ischemia in a canine model. This study was done to evaluate whether TNF also played a role in skeletal muscle ischemia-reperfusion injury since IL-1 and TNF have inter-related functions. In twelve adult mongrel dogs (28-32 kg) one gracilis muscle was subjected to six hours of normothermic ischemia followed by normothermic reperfusion. The contralateral side served as a control and remained normally perfused throughout the experiment. Gracilis venous samples were collected at pre-ischemia and one hour of reperfusion. Systemic (arterial) blood samples were taken simultaneously with the venous samples at one hour of reperfusion. At the end of the experiment the muscles were harvested and amount of necrosis quantitated by serial transections, nitroblue tetrazolium staining and computerized planimetry. Muscle necrosis on the experimental side was found to be 48.86 +/- 5.37%. Sera were analyzed for TNF activity using a bioassay. TNF levels in the gracilis venous effluent at one hour of reperfusion were not significantly different from the simultaneous systemic (arterial) levels (27.15 +/- 5.05 pg/ml vs 18.23 +/- 4.27 pg/ml). Pre-ischemic levels of TNF were 96.50 +/- 20.12 pg/ml, which was significantly higher than either venous or arterial levels obtained after one hour of reperfusion (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Diltiazem restores IL-2, IL-3, IL-6, and IFN-gamma synthesis and decreases host susceptibility to sepsis following hemorrhage

Various beneficial effects of calcium channel blockers on cell and organ function following endotoxic shock, organ ischemia, and reperfusion have been reported; however, it is not known whether these agents have any salutary or deleterious effects on immune responses after low-flow conditions. Therefore, the aim of this study was to determine (a) the effect of hemorrhage on lymphocyte IL-2, IL-3, IL-6, and IFN-gamma synthesis, and (b) whether diltiazem has any salutary or adverse effects on these parameters when administered following hemorrhage and resuscitation. To study this, C3H/HeN mice were bled to a mean blood pressure of 35 mm Hg, maintained at that level for 60 min, and resuscitated with shed blood plus twice that volume of Ringer's lactate. Immediately following resuscitation mice received either diltiazem (2400, 800, or 400 micrograms/kg body wt), or an equivalent volume of saline. The mice were sacrificed 24 hr later, splenic lymphocytes were obtained, and their capacity to produce lymphokines was assessed. The results indicated that in the vehicle-treated animals, hemorrhage significantly decreased (P less than 0.05) IL-2, IL-3, IL-6, and IFN-gamma synthesis by 82 +/- 19%, 64 +/- 28%, 71 +/- 11%, and 86 +/- 14%, respectively. However, diltiazem (400 but not 2400 micrograms/kg) treatment after hemorrhage restored lymphocyte capacity to produce IL-2, IL-3, IL-6, and IFN-gamma (P less than 0.05). Additional groups of animals were subjected to sepsis by cecal ligation and puncture 3 days following hemorrhage.(ABSTRACT TRUNCATED AT 250 WORDS)     

Role of the kidney in plasma cytokine removal in sepsis syndrome: a pilot study

BACKGROUND: At the onset of sepsis, endotoxins or other components of the gram-negative capsular wall stimulate the synthesis of pro-inflammatory cytokines by activating the monocyte-macrophage system. In this context, interleukin-1 beta (IL-1), tumor necrosis factor-alpha (TNF) and IL-6 are considered co-responsible for the clinical picture of sepsis syndrome. Many organs can be involved, and kidney dysfunction occurs early with a picture of non-oliguric acute renal failure (NOARF) or oliguric acute renal failure (OARF). This study aimed to investigate the role of the kidney in plasma removal of some pro-inflammatory cytokines in the first 24 hr after the diagnosis of sepsis syndrome, when, according to the peak concentration hypothesis, their plasma concentration is maximal. 18 septic patients, six patients with normal renal function (NRF), six with NOARF and six with OARF were selected for the study. We measured the plasma levels and urinary excretion of IL-1, TNF and IL-6 at the moment of sepsis diagnosis (base-line) and 24 hr later. Moreover, urinary excretion of IL-1 and IL-6 was done in the same interval by measuring the percentage of fractional excretion (FE%) of these cytokines. RESULTS: Multivariate analysis (ANOVA) showed no significant difference in plasma IL-1 levels at baseline in the NRF, NOARF and OARF patients (p=0.11), whereas a significant increase was found in OARF patients at 24 hr, p<0.023. OARF patients presented significantly higher IL-6 plasma levels compared with the other two groups, both at baseline (p<0.0002) and at 24 hr (p<0.0001). Plasma TNF levels were not significantly different at baseline (p=0.184), whereas the OARF group showed a significant increase at 24 hr, (p<0.05). The urinary FE of IL-1 was 1.2 +/- 0.6% in NRF, and 1.0 +/- 0.4% in NOARF (ns), the FE of IL-6 was 1.4 +/- 0.8% in NRF and 1.3 +/- 0.3% in NOARF (ns). A negative in-significant correlation was found between the plasma concentration and FE of IL-1 beta (r=-0.33, p<0.07). Urinary excretion of IL-6 was significantly related with urinary IL-1 beta, both expressed as pg/ml/mg of urinary creatinine (r=0.85, p<0.0001). No significant relation was found between IL-1 and IL-6 plasma concentrations or between plasma concentration and FE of IL-6. CONCLUSION: These results suggest that at disease onset, the kidney removes some pro-inflammatory cytokines from the plasma of septic patients until diuresis is preserved. As it has been demonstrated that NOARF patients have a better prognosis than OARF patients and their survival in sepsis syndrome seems to be inversely related to the plasma pro-inflammatory cytokine levels, diuresis maintenance by diuretic infusion can be important to improve patient prognosis.     

Do female sex steroids adversely or beneficially affect the depressed immune responses in males after trauma-hemorrhage?

HYPOTHESIS: Administration of female sex steroids in males after trauma-hemorrhage has salutary effects on the depressed immune responses. DESIGN: Randomized laboratory experiment. INTERVENTIONS: Male C3H/HeN mice were subjected to midline laparotomy and hemorrhagic shock (35+/-5 mm Hg for 90 minutes, then resuscitation) or sham operation and received subcutaneous 17beta-estradiol (40 microg/kg body weight) or corn oil vehicle at the beginning of resuscitation. MAIN OUTCOME MEASURES: At 24 hours after hemorrhage, the animals were killed and plasma 17beta-estradiol and IL-6, splenocyte interleukin (IL) 2, IL-3, and IL-10 production as well as splenic and peritoneal macrophage IL-1beta, IL-10, and IL-6 release were measured. RESULTS: Splenocyte IL-2 and IL-3 release were significantly depressed after hemorrhage in vehicle-treated mice (P<.05, analysis of variance). Treatment with 17beta-estradiol after hemorrhage led to the restoration of splenocyte IL-2 and IL-3 release. The depressed proinflammatory cytokine (IL-1 and IL-6) release seen in splenic and peritoneal macrophages was restored in the 17beta-estradiol-treated hemorrhage group. In contrast, the sustained release of the anti-inflammatory cytokine IL-10 by splenocytes and splenic and peritoneal macrophages in vehicle-treated mice after hemorrhage was decreased in 17beta-estradiol-treated mice. The increase in circulating IL-6 levels after hemorrhage was significantly attenuated in 17beta-estradiol-treated mice. Although administration of 17beta-estradiol increased plasma 17beta-estradiol levels by approximately 100% in sham as well as hemorrhage groups, improved immune responses were seen only in posthemorrhage 17beta-estradiol-treated mice. There was no adverse effect of 17beta-estradiol treatment in the sham or posthemorrhage groups. CONCLUSION: Since administration of a single dose of 17beta-estradiol in males after trauma-hemorrhage restores the immune functions and decreases circulating levels of IL-6, hormones with estrogenic properties should be considered as safe and novel therapeutic agents for restoring the immune responsiveness in male trauma victims.