Seigo Hidaka

Effects of an angiotensin-converting enzyme inhibitor on the inflammatory response in in vivo and in vitro models.

Objective:Sepsis remains a major health threat in intensive care medicine. The renin-angiotensin system (ACE) affects inflammatory responses. In addition, angiotensin-converting enzyme inhibitors act to ameliorate lung injury. To investigate whether the widely used ACE inhibitor enalapril, used to treat hypertension, could inhibit secretion of cytokines and high-mobility group box 1 (HMGB1) protein, thus reducing lung damage in a rat model of lipopolysaccharide (LPS)-induced sepsis. Design:Randomized, prospective animal study. Setting:University medical center research laboratory. Subjects:Male Wistar rats. Interventions:LPS was administered intravenously to rats, with or without intraperitoneal pretreatment with enalapril. In addition, mouse macrophage RAW264.7 cells were stimulated with LPS, with and without simultaneous enalapril treatment. Measurements and Main Results:Histologic examination showed marked reduction of interstitial congestion, edema, inflammation, and hemorrhage in lung tissue harvested 12 hours after treatment with both agents compared with LPS administration alone. Plasma concentration of angiotensin II was strongly induced by LPS; this induction was inhibited by the enalapril pretreatment. Likewise, LPS-induced secretion of proinflammatory cytokines and HMGB1 protein was inhibited by enalapril. The presence of HMGB1 protein in the lung was examined directly by immunohistochemistry; the number of stained cells was significantly lower in LPS-treated animals that also received enalapril. In the in vitro studies, enalapril administration inhibited the phosphorylation of IkappaB. Conclusions:The ACE inhibitor enalapril blocked the LPS-induced inflammatory response and protected against the acute lung injury normally associated with endotoxemia in this rat sepsis model. Given these results, enalapril is a strong candidate as a therapeutic agent for sepsis.

Danaparoid sodium inhibits systemic inflammation and prevents endotoxin-induced acute lung injury in rats

IntroductionSystemic inflammatory mediators, including high mobility group box 1 (HMGB1), play an important role in the development of sepsis. Anticoagulants, such as danaparoid sodium (DA), may be able to inhibit sepsis-induced inflammation, but the mechanism of action is not well understood. We hypothesised that DA would act as an inhibitor of systemic inflammation and prevent endotoxin-induced acute lung injury in a rat model.MethodsWe used male Wistar rats. Animals in the intervention arm received a bolus of 50 U/kg of DA or saline injected into the tail vein after lipopolysaccharide (LPS) administration. We measured cytokine (tumour necrosis factor (TNF)α, interleukin (IL)-6 and IL-10) and HMGB1 levels in serum and lung tissue at regular intervals for 12 h following LPS injection. The mouse macrophage cell line RAW 264.7 was assessed following stimulation with LPS alone or concurrently with DA with identification of HMGB1 and other cytokines in the supernatant.ResultsSurvival was significantly higher and lung histopathology significantly improved among the DA (50 U/kg) animals compared to the control rats. The serum and lung HMGB1 levels were lower over time among DA-treated animals. In the in vitro study, administration of DA was associated with decreased production of HMGB1. In the cell signalling studies, DA administration inhibited the phosphorylation of IκB.ConclusionDA decreases cytokine and HMGB1 levels during LPS-induced inflammation. As a result, DA ameliorated lung pathology and reduces mortality in endotoxin-induced systemic inflammation in a rat model. This effect may be mediated through the inhibition of cytokines and HMGB1.

Gabexate Mesilate Inhibits the Expression of HMGB1 in Lipopolysaccharide-Induced Acute Lung Injury

High mobility group box 1 (HMGB1) is an important late mediator of acute lung injury. Gabexate mesilate (GM) is a synthetic protease inhibitor with some anti-inflammatory action. We aimed to evaluate the effect of GM on HMGB1 in lipopolysaccharide (LPS)-induced lung injury in rats. Prior to the injection of LPS to induce lung injury, rats were administered saline or GM. Injury to the lung and expression of HMGB1, plasminogen activator inhibitor-1 (PAI-1), and protease-activated receptor-2 (PAR-2) were examined. In an accompanying in vitro study, we performed LPS stimulation under GM administration in a mouse macrophage cell line and measured the quantity of HMGB1 and cytokines in the supernatant, and cell signal in the cells. Histologic examination revealed that interstitial edema, leukocytic infiltration, and HMGB1 protein expression were markedly reduced in the GM+LPS group compared wih the LPS group. Furthermore, LPS-induced increases in PAI-1 and PAR-2 activity and in plasma HMGB1 concentrations were lower in the rats given both GM and LPS than in the rats given LPS alone. Release of HMGB1 and cytokines from the cell after the administration of LPS were decreased by GM. Phosphorylation of IκB was inhibited by GM. GM may have inhibited PAI-1 and PAR-2, thereby indirectly inhibiting HMGB1 and reducing tissue damage in the lung. This indicates that GM can inhibit lung injury induced by LPS in rats. GM is a candidate for use in novel strategies to prevent or minimize lung injury in sepsis.

The antioxidant EPC-K1 attenuates renal ischemia-reperfusion injury in a rat model.

Background: Acute kidney injury (AKI) occurs frequently in the intensive care unit. A primary cause is renal ischemia/reperfusion (I/R) injury, during which excess reactive oxygen species (ROS) are produced. ROS subsequently damage renal cells, leading to the development of AKI. Here, we investigated whether renal I/R injury could be attenuated by the antioxidant EPC-K1. Methods: We divided male Wistar rats into the following three groups: (1) a renal I/R group, (2) an EPC-K1 + renal I/R group and (3) a control group. Rats were sacrificed 24 h after treatment (I/R or sham). To measure oxidative stress in renal tissue, histological examinations were performed and serum levels of blood urea nitrogen (BUN) and creatinine were measured. The antioxidant action of EPC-K1 was also evaluated in RAW264.7 cells stimulated with antimycin A. Results: Serum BUN and creatinine levels were elevated in the I/R group; however, this increase was significantly attenuated by EPC-K1 in the EPC-K1 + I/R group. Renal tissue injury was also significantly lower in the EPC-K1 + I/R group compared with the I/R group. In vitro experiments showed that EPC-K1 significantly attenuated the generation of ROS induced by antimycin A. Conclusion: In our study, EPC-K1 was able to attenuate AKI due to renal I/R by reducing oxidative stress. These results suggest that EPC-K1 may be effective against various types of I/R injury.

Filtration leukocytapheresis therapy ameliorates lipopolysaccharide-induced systemic inflammation in a rat model.

BACKGROUND Systemic inflammation, which is associated with various conditions such as sepsis, pneumonia, and trauma, can lead to multiple organ dysfunction syndrome. Systemic inflammation can be life-threatening and is often associated with conditions seen in the intensive care unit. Leukocytes exert a proinflammatory effect and damage various tissues during systemic inflammation. The purpose of this study was to determine whether leukocytapheresis therapy can prevent lipopolysaccharide (LPS)-induced systemic inflammation in a rat model. MATERIALS AND METHODS Male Wistar rats weighing 250 to 300 g were used for all experiments. Rats received an LPS injection, followed 6 h later by filtration leukocytapheresis or mock treatment for 30 min under sevoflurane anesthesia. Systemic inflammation was induced in rats by intravenous LPS injection (7.5 mg/kg) followed by filtration leukocytapheresis. Following blood filtration, we evaluated lung and liver histology, serum cytokine levels, and survival rate of rats for each treatment group. RESULTS Histologic examination revealed markedly reduced inflammatory injury in lung and liver tissue harvested from rats 24 h after leukocytapheresis therapy compared with mock treatment. LPS-induced tumor necrosis factor (TNF)-α and interleukin (IL)-6 secretion was also inhibited by leukocytapheresis therapy. Moreover, survival was significantly increased in rats treated with high-efficiency leukocytapheresis compared to mock-treated rats (P<0.05). CONCLUSIONS Taken as a whole, our findings indicate that filtration leukocytapheresis therapy protects against LPS-induced systemic inflammation. Therefore, leukocytapheresis shows potential as a new therapy for various systemic inflammatory diseases.

Removal of 17 Cytokines, HMGB1, and Albumin by Continuous Hemofiltration Using a Cellulose Triacetate Membrane: An Ex Vivo Study

BACKGROUND Hemofiltration is often used to treat critically ill patients with renal failure and septic shock. Although hemofiltration has been reported to remove humoral mediators such as cytokines, most studies have investigated the removal of only limited kinds of cytokines. Here, we assessed the removal of 17 cytokines, HMGB1, and albumin by continuous hemofiltration (CHF) with a cellulose triacetate membrane (2.1 m(2) or 1.1 m(2)). METHODS The subjects were six healthy volunteers. We collected 400 mL blood into containers with heparin. After adding 1 mg/mL lipopolysaccharide, the blood was incubated at 39°C for 12 h and then filtered through a closed hemofiltration circuit (1 or 2 L/h). Sixty and 240 min after beginning hemofiltration, samples were collected from the outlet (arterial) side, inlet (venous) side, and filtrate port. Blood levels of cytokines, HMGB1, and albumin were determined at each time point. RESULTS Increasing the flow rate significantly increased cytokine clearance. Increasing the membrane area of the hemofilter significantly changed the sieving coefficient of only five cytokines (IL-1β, IL-6, MCP-1, MIP-1β, HMGB1). For many cytokines, the sieving coefficient did not decline during the 240-min CHF procedure. CONCLUSION Although all 17 cytokines, HMGB1, and albumin were detected in the filtrate, the SC and clearance varied widely. For numerous cytokines, clearance increased with the higher filtration flow rate. We demonstrated that CHF removed many cytokines and HMGB1, but was inefficient at removing albumin.

The impact of oxidative stress levels on the clinical effectiveness of sivelestat in treating acute lung injury: an electron spin resonance study.

BACKGROUND Sivelestat, a neutrophil elastase inhibitor, has been used to treat acute lung injury (ALI) with varying levels of clinical success. Variable baseline levels of oxidative stress in patients with ALI have been proposed as one explanation for inconsistent results. METHODS Using a bedside electron spin resonance spectrometer, we evaluated electron spin resonance signal intensities of serum ascorbyl free radicals supplemented with dimethyl sulfoxide (AFR/DMSO) in patients with ALI. RESULTS We found a positive correlation between AFR/DMSO and ascorbate levels, suggesting that serum AFR/DMSO measurements may serve as a surrogate for real-time assessments of oxidative stress. Levels of AFR/DMSO in patients with ALI were significantly lower than those found in healthy controls. Stratified analyses revealed that baseline AFR/DMSO levels were significantly lower in patients with ALI who failed to respond to sivelestat compared with those who did respond. CONCLUSIONS Our results suggest that the clinical efficacy of sivelestat is dependent on baseline oxidative stress levels.

Anesthetic management of a patient with hyperthyroidism due to hydatidiform mole

Secondary hyperthyroidism can often complicate gestational trophoblastic disease, a malignant uterine cancer. We report here the perioperative management of hyperthyroidism due to hydatidiform mole. A 53-year-old woman underwent emergency surgery due to suspicion of hydatidiform mole. Tachycardiac atrial fibrillation was detected by electrocardiography at the preoperative examination. No abnormalities were found in blood count, coagulation, biochemical tests, chest radiographs, or respiratory function. General anesthesia with nitrous oxide, oxygen, and sevoflurane, combined with fentanyl and 1% mepivacaine, was administered intermittently from an epidural catheter. Intraoperative events included hypotension and tachycardia, although in general, tachycardia was prevented with antiarrhythmic agents and transfusion with a plasma expander and crystalloid fluid. Hyperthyroidism was highly suspected from the patient’s clinical course and was confirmed by high levels of preoperative serum free triiodothyronine (T3) and thyroxine (T4). The patient became euthyroid within a few days after mole evacuation and did not require an antiarrhythmic agent after her return to the inpatient ward.

RETRACTED: Continuous Hemodiafiltration Therapy Ameliorates LPS-Induced Systemic Inflammation in a Rat Model

BACKGROUND Systemic inflammation can result in multiple organ dysfunction syndrome, a potentially life-threatening condition. Some reports suggest that continuous hemodiafiltration can effectively remove proinflammatory cytokines from circulation during systemic inflammation. In the present study, we investigated whether continuous hemodiafiltration therapy could prevent LPS-induced systemic inflammation and improve survival in a rat model. MATERIALS AND METHODS Male Wistar rats were injected with lipopolysaccharide (LPS; 7.5 mg/kg body weight), and 6 h later were treated with either single-pass hemofiltration (C group), continuous hemofiltration (CHF group), continuous hemodiafiltration (CHDF group), or mock filtration (Control group). We performed histologic examinations of lung and liver tissues, determined serum cytokine levels, and survival rates for each treatment group, and compared cytokine removal between CHF and CHDF therapies. RESULTS Histologic examination revealed significant reduction in inflammation in lung and liver tissues harvested 24 h after CHDF compared with the Control group. Likewise, LPS-induced serum TNF-α and IL-6 levels decreased with continuous hemodiafiltration along with a significant improvement in survival. After 30 min of treatment, both CHF and CHDF removed significant amounts of TNF-α and IL-6 from the blood. However, serum cytokine levels measured before and after filtration were not significantly different. CONCLUSIONS Continuous hemodiafiltration therapy lowered inflammatory cytokines and increased survival rates in a rat model of systemic inflammation. Therefore, continuous hemodiafiltration may be a potential therapy for use against various systemic inflammatory diseases.

Pharmacokinetics of ceftriaxone in patients undergoing continuous renal replacement therapy

Abstract Background: The duration of time for which the serum levels exceed the minimum inhibitory concentration (MIC) is an important pharmacokinetics (PK)/pharmacodynamics (PD) parameter correlating with efficacy for the antibiotic, ceftriaxone (CTRX). However, no reports exist regarding the PK or PD in patients undergoing continuous renal replacement therapy (CRRT). The purpose of this study was to examine the PK and safety of CTRX in patients undergoing CRRT in order to establish safer and more effective regimens. Methods: CTRX (1 g once a day) was intravenously administered four or more times to nine patients undergoing CRRT. Blood was collected after administration to measure CTRX concentrations in serum and the filtration fraction of CRRT by high-performance liquid chromatography. In addition to calculating PK parameters from serum CTRX, we (a) estimated by simulation CTRX concentrations when the dose interval was extended to once every 2 or 3 days, (b) calculated CTRX clearance via CRRT from CTRX concentrations in the filtration fraction, and (c) assessed the safety of CTRX use. Results: Total body clearance and the half-life of CTRX were 7.46 mL/min (mean) and 26.5 h, respectively, in patients undergoing CRRT. CTRX was found in the filtration fraction, and the estimated clearance by CRRT was about 70% of total body clearance. Simulations revealed that even when the dose interval is increased to 2 or 3 days, CTRX would retain its efficacy. Conclusions: Our findings suggest that, depending on the condition of patients undergoing CRRT, CTRX could be used safely against pathogens with a CTRX MIC ≤2 µg/mL, even when extending the dose interval.