Prostaglandin E1 suppresses tumor necrosis factor-alpha and interleukin-10 production by lipopolysaccharides-stimulated mononuclear cells

Does PGE₁ vasodilator prevent orthopaedic implant-related infection in diabetes? Preliminary results in a mouse model

BACKGROUND

Implant-related infections are characterized by bacterial colonization and biofilm formation on the prosthesis. Diabetes represents one of the risk factors that increase the chances of prosthetic infections because of related severe peripheral vascular disease. Vasodilatation can be a therapeutic option to overcome diabetic vascular damages and increase the local blood supply. In this study, the effect of a PGE₁ vasodilator on the incidence of surgical infections in diabetic mice was investigated.

METHODOLOGY

A S. aureus implant-related infection was induced in femurs of diabetic mice, then differently treated with a third generation cephalosporin alone or associated with a PGE₁ vasodilator. Variations in mouse body weight were evaluated as index of animal welfare. The femurs were harvested after 28 days and underwent both qualitative and quantitative analysis as micro-CT, histological and microbiological analyses.

RESULTS

The analysis performed in this study demonstrated the increased host response to implant-related infection in diabetic mice treated with the combination of a PGE₁ and antibiotic. In this group, restrained signs of infections were identified by micro-CT and histological analysis. On the other hand, the diabetic mice treated with the antibiotic alone showed a severe infection and inability to successfully respond to the standard antimicrobial treatment.

CONCLUSIONS

The present study revealed interesting preliminary results in the use of a drug combination of antibiotic and vasodilator to prevent implant-related Staphylococcus aureus infections in a diabetic mouse model.

Prostaglandin E1 dose-dependently promotes stability of atherosclerotic plaque in a rabbit model

This study evaluated the effect of prostaglandin E1 (PGE1) on the stability of atherosclerotic plaque. A vulnerable plaque model was established in rabbits, using balloon injury combined with a high-cholesterol diet. The rabbits were distributed into a control group, a low-dose PGE1 treatment group, a moderate-dose PGE1 treatment group, a high-dose PGE1 treatment group, and a simvastatin treatment group, with treatments lasting for 4 weeks. At week 13 (at the end of the experiments), atherosclerotic plaque was triggered by injection of Russell's viper venom (Chinese) and histamine. Serological, pathological, immunohistochemical, and gene-expression studies were subsequently performed. PGE1 treatment did not alter serum lipid levels; however, PGE1 dose-dependently increased the thickness of the fibrous caps, and decreased the plaque vulnerability index. The plaque contents of macrophage- and the mRNA levels of monocyte-chemotactic protein-1, matrix metalloproteinase-1, and matrix metalloproteinase-9 were markedly reduced in all of the PGE1 treatment groups, with the high-dose of PGE1 being more effective than the simvastatin treatment. These findings suggest that PGE1 dose-dependently enhances the stability of atherosclerotic plaque. The high-dose of PGE1 presented more protection in terms of inhibiting macrophage accumulation and inflammatory expression in plaque. Our findings suggest a novel drug for the treatment of atherosclerosis.

Differential effect of prostaglandins E1 and E2 on lipopolysaccharide-induced adhesion molecule expression on human monocytes

The effect of prostaglandins E1 and E2 on the 1 ng/ml lipopolysaccharide-induced expression of intercellular adhesion molecule (ICAM)-1, B7.1, B7.2, CD40 and CD40 ligand (CD40L) on monocytes was examined. Prostaglandin E1 suppressed B7.1 and CD40 expression, but prostaglandin E2 did not effect on any type of adhesion molecule expression. Both prostaglandins inhibited tumor necrosis factor (TNF)-alpha production and T-cell proliferation of lipopolysaccharide-treated human peripheral blood mononuclear cells (PBMC). Among prostaglandin E1 receptors (IP/EP1/EP2/EP3/EP4) agonists, ONO-1301, a prostanoid IP-receptor agonist, prevented B7.1 and CD40 expression. ONO-AE1-259-01 a prostanoid EP2-receptor agonist, ONO-AE1-329, a prostanoid EP4-receptor agonist, and ONO-1301 inhibited TNF-alpha production and T-cell proliferation. Moreover, anti-B7.1 and anti-CD40 Abs prevented lipopolysaccharide-induced TNF-alpha production and T-cell proliferation. Therefore, the effect of prostaglandin E1 on TNF-alpha production and T-cell proliferation might depend on the inhibition of B7.1 and CD40 expression, but that of prostaglandin E2 might be independent of adhesion molecules expression. In conclusion, the mechanism responsible for the effect of prostaglandin E1 on lipopolysaccharide-induced responses is distinct from that of prostaglandin E2.

Effects of isoflurane-induced and prostaglandin E(1)-induced hypotension on cytokine responses to oral and maxillofacial surgery

STUDY OBJECTIVE

To evaluate the effect of induced hypotension with isoflurane or prostaglandin E(1) (PGE(1)) on cytokine responses to surgery.

DESIGN

Prospective, randomized study.

SETTING

University hospital.

PATIENTS

24 ASA physical status I and II patients undergoing elective oral and maxillofacial surgery.

INTERVENTIONS

Patients were randomly allocated to three groups be anesthetized in the normotension (Control group), isoflurane-induced hypotension (Isoflurane-H group), and PGE(1)-induced hypotension (PGE(1)-H group). Mean arterial pressure during hypotension was maintained at approximately 80% of baseline values.

MEASUREMENTS AND MAIN RESULTS

Blood samples were taken before induction of anesthesia and during and after hypotension. Plasma tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), and interleukin-10 (IL-10) levels were measured using enzyme-linked immunosorbent assay. There were no differences in TNF-alpha or IL-10 levels among the groups. However, the elevation of the plasma IL-6 level in the PGE(1)-H group was found during hypotension, compared with the control group (p < 0.05).

CONCLUSIONS

PGE(1)-induced hypotension has an effect on IL-6 response to oral and maxillofacial surgery.

Prostaglandin E1 reduces compression trauma-induced spinal cord injury in rats mainly by inhibiting neutrophil activation

Prostaglandin E1 (PGE1), a potent vasodilator, was recently reported to inhibit both neutrophil activation and monocytic production of tumor necrosis factor-alpha (TNF-alpha) in vitro. We previously reported that TNF-alpha was critically involved in the development of motor disturbances by increasing the accumulation of neutrophils at the site of injury in rats subjected to compression trauma-induced spinal cord injury. Therefore, it is possible that PGE1 reduces motor disturbances by inhibiting neutrophil activation in rats subjected to spinal cord injury. We examined this possibility in a rat model of spinal cord injury (SCI). Motor disturbances induced by spinal cord compression were evaluated using the inclined plane test, and footprint analysis. Accumulation of neutrophils at the site of trauma was evaluated by measuring tissue myeloperoxydase (MPO) activity. Tissue levels of TNF-alpha were determined using an enzyme-linked immunosorbent assay. Motor disturbances induced by spinal cord compression were significantly attenuated in rats administered PGE1. A histological examination revealed that intramedullary hemorrhages, observed 24 h after trauma, were markedly reduced in animals administered PGE1. Increases in the tissue levels of TNF-alpha and MPO activity in the damaged segment of spinal cord were significantly inhibited in animals that had received PGE1. These observations suggested that PGE1 reduces motor disturbances by inhibiting neutrophil activation directly or indirectly through the inhibition of TNF-alpha production at the site of injury. These effects of PGE1 might at least partly contribute to therapeutic effect on SCI in rats.

A randomized controlled trial of misoprostol monotherapy for canine atopic dermatitis: effects on dermal cellularity and cutaneous tumour necrosis factor-alpha

In this blinded randomized placebo-controlled trial, 20 dogs with atopic dermatitis (AD) were given placebo (8 dogs) or misoprostol (12 dogs) at 5 micro g kg-1, orally, three times daily for 3 weeks. Administration of the active drug, but not of placebo, led to a significant decrease in lesional and pruritus scores. The median reduction from baseline of both scores was approximately 30%. Misoprostol therapy did not lead to decreases of dermal cell counts or skin tumour necrosis factor (TNF)alpha mRNA copy numbers that were significantly different from those of placebo. Skin TNFalpha protein production, assessed using indirect immunofluorescence, decreased or remained unchanged in dogs receiving misoprostol. In contrast, post treatment TNFalpha fluorescence scores were higher in all but two dogs given placebo. The changes from baseline of TNFalpha fluorescence scores did not correlate significantly with those of lesional or pruritus indices. These observations confirm the modest efficacy of misoprostol for treatment of canine AD and suggest that its mild anti-allergic effects are not associated with either inhibition of inflammatory cell emigration or TNFalpha production.

Differential modulation of interleukin-6 and interleukin-10 by diclofenac in patients undergoing major surgery

BACKGROUND

Prostaglandins modulate cytokine release though increases in cAMP, regulating interleukin (IL) 6 and IL-10. Diclofenac inhibits cyclo-oxygenase activity and hence prostaglandin production. We hypothesized that diclofenac would affect release of IL-6 and IL-10 and modulate the immune response.

METHODS

In a randomized, double-blind, placebo-controlled study, we investigated the effect of diclofenac in patients undergoing major urological surgery. Patients were randomized to receive either diclofenac (50 mg orally every 8 h the day before surgery and 75 mg i.m. every 12 h on the day of surgery, n = 23) or placebo (n = 23). Standardized combined general anaesthesia and epidural analgesia was administered. Serum IL-6, IL-10 and cortisol were measured before surgery and 30 min and 2, 6, 12 and 24 h after skin incision. Temperature, leucocyte count and C-reactive protein concentration were measured before surgery and after 24 h.

RESULTS

IL-6 and IL-10 concentrations increased, reaching peak levels at 12 and 6 h respectively in both groups. At 12 h, the IL-6 concentration was significantly lower in patients receiving diclofenac than in those receiving placebo (P = 0.003). In contrast, IL-10 concentration at 6 h was higher in diclofenac-treated patients (P = 0.008), and this was associated with less pyrexia (P = 0.03), a lower leucocyte count (P = 0.0002) and a lower C-reactive protein concentration (P = 0.0039). Serum cortisol concentration was similar in the two groups of patients until 24 h, when the concentration was lower in patients who received diclofenac (P = 0.002). Cortisol concentration correlated with IL-6 concentration at 24 h.

CONCLUSIONS

Administration of diclofenac was associated with lower IL-6 and higher IL-10 concentrations, and lower leucocyte count, C-reactive protein concentration and temperature. Diclofenac may have an anti-inflammatory role in major surgery.

Is insulin an antiinflammatory molecule?

I suggest that insulin suppresses the secretion and antagonizes the harmful effects of tumor necrosis factor-alpha, macrophage migration-inhibitory factor, and superoxide anion. Therefore, the glucose-insulin-potassium regimen might be beneficial in acute myocardial infarction and useful in the management of patients with septicemia, septic shock, and other inflammatory diseases in which tumor necrosis factor-alpha and macrophage migration-inhibitory factor have important roles.

Intraoperative prostaglandin E1 improves antimicrobial and inflammatory responses in alveolar immune cells

OBJECTIVE

Anesthesia and surgery decrease antimicrobial and increase proinflammatory functions of alveolar immune cells. Thus, anti-inflammatory agents that do not further suppress antimicrobial functions are required. We tested the hypothesis that intraoperative prostaglandin E1 (PGE1) suppresses proinflammatory responses and prevents the reduction in antimicrobial responses of alveolar immune cells.

DESIGN

Prospective, randomized, controlled, double-blind study.

SETTING

University hospital.

PATIENTS

A total of 40 patients undergoing elective orthopedic surgery under propofol/fentanyl anesthesia.

INTERVENTION

In double-blind fashion, the patients received PGE1 from the beginning to the end of surgery (PGE1 group, n = 20) or nothing (control group, n = 20).

METHODS AND MAIN RESULTS

Alveolar immune cells were harvested by bronchoalveolar lavage immediately after induction of anesthesia; 2, 4, and 6 hrs after induction of anesthesia; and at the end of surgery. We measured opsonized and nonopsonized phagocytosis. Microbicidal activity was evaluated to directly kill Listeria monocytogenes in alveolar macrophages. Finally, we determined the expression of proinflammatory cytokines including interleukin (IL)-1beta, IL-8, interferon-gamma, and tumor necrosis factor-alpha, and that of anti-inflammatory cytokines (IL-4 and IL-10) by semiquantitative polymerase chain reaction. Nonopsonized and opsonized phagocytosis and microbicidal activity of alveolar macrophages decreased and the expression of genes for all pro- and anti-inflammatory cytokines increased significantly over time in both groups. Starting 2-4 hrs after induction of anesthesia, the increases in gene expression of proinflammatory cytokines were 1.5-3 times smaller in the PGE1 than in the control group. Starting 6 hrs after anesthesia, the increase in gene expression of IL-10 was 1.5-3 times greater in the PGE1 than in the control group. Intraoperative decreases in phagocytic and microbial activities were the same in the two groups.

CONCLUSION

Intraoperative PGE1 not only suppressed proinflammatory responses, but also protected antimicrobial functions of alveolar macrophages, possibly because PGE1 is mostly inactivated in the pulmonary intravascular space. Our results suggest that intraoperative PGE1 protects the pulmonary immune defense in alveolar immune cells.

Elevated serum levels of soluble L-selectin in patients with systemic sclerosis declined after intravenous injection of lipo-prostaglandin E1

To determine whether serum soluble L-selectin (sL-selectin) levels are elevated in patients with systemic sclerosis (SSc) and whether serum sL-selectin levels change after treatment with lipo-prostaglandin E1 (lipo-PGE1), serum sL-selectin levels were examined by ELISA in patients with SSc (n=24), psoriasis vulgaris (n=22), and contact dermatitis (n=9), as well as normal control subjects (n=26). In five patients with SSc, serum sL-selectin levels were examined before and after intravenous injections of lipo-PGE1. Serum sL-selectin levels were significantly increased in patients with SSc (P<0.01) than those in normal control subjects. The elevated serum sL-selectin levels in patients with SSc significantly decreased 1 day (P<0.05), 7 days (P<0.05) and 14 days (P<0.05) after starting the treatment with lipo-PGE1. These results suggest that L-selectin may be involved in the disease process in SSc, and lipo-PGE1 may alter some inflammatory events in SSc.

The influence of liposome-encapsulated prostaglandin E1 on hydrogen peroxide concentrations in the exhaled breath of patients with the acute respiratory distress syndrome

Hydrogen peroxide (H2O2) levels are increased in the exhaled breath of patients with the acute respiratory distress syndrome (ARDS). Because liposome-encapsulated prostaglandin E1 (PGE1) downregulates the CD11/CD18 receptor of the neutrophil, thereby limiting endothelial adhesion, the use of this drug should decrease the excretion of H2O2 in the expiratory condensate of patients with ARDS. Patients > 11 yr of age with ARDS (diffuse, patchy infiltrates by chest radiograph; Pao2/fraction of inspired oxygen [P/F] ratio < or = 200 mm Hg; pulmonary capillary wedge pressure < or = 18 mm Hg; and the requirement for mechanical ventilation) were randomized to receive placebo (n = 14) or escalating doses (0.15-3.6 micrograms/kg) of liposomal PGE1 (n = 14) every 6 h for up to 7 days. Condensate was collected every morning from the expiratory tubing that was submerged in an ice saltwater bath (-5 degrees C). H2O2 levels were measured by using a horseradish peroxidase assay. Other data collected included white blood cell count and P/F ratios. There was no significant difference in the concentration of H2O2 in the expiratory condensate between the liposomal PGE1 group and the control group either before (0.99 +/- 0.52 vs 0.93 +/- 0.48 mumol/L) or during treatment (1.04 +/- 0.45 vs 0.76 +/- 0.25 mumol/L). Liposomal PGE1 treatment improved the P/F ratio and decreased the white blood cell count over time. Despite its ability to downregulate the CD11/CD18 neutrophil receptor, liposomal PGE1 did not reduce exhaled H2O2 excretion.

IMPLICATIONS

White blood cells (WBC) are thought to be part of the cause of the acute respiratory distress syndrome, a lung disease. WBC in the lung produce hydrogen peroxide, which is exhaled. Liposomal PGE1 inhibits WBC function but was found to have no effect in decreasing exhaled hydrogen peroxide in patients with the acute respiratory distress syndrome.