Takashi Kawasaki

Ketamine suppresses proinflammatory cytokine production in human whole blood in vitro.

UNLABELLED The production of proinflammatory cytokines, such as tumor necrosis factor (TNF) a, interleukin (IL)-6, and IL-8, increases in patients with sepsis; marked production causes organ failure and septic shock. We previously reported that ketamine suppressed lipopolysaccharide (LPS)-induced TNF-alpha production in mice. However, there are no reports on the effect of ketamine on cytokine production in human whole blood. Therefore, in this study, we investigated the efficacy of ketamine on LPS-induced TNF-alpha, IL-6, and IL-8 production and recombinant human (rh) TNF-a-induced IL-6 and IL-8 production in human whole blood. After adding different doses of ketamine to whole blood, the blood was stimulated with LPS or rhTNF. After incubation, the plasma TNF-alpha activity and IL-6 and IL-8 concentrations were measured using the L929 cell cytotoxic assay or an enzyme-linked immunoassay. Ketamine significantly suppressed LPS-induced TNF-alpha production at concentrations >20 microg/mL. At concentrations >100 microg/mL, ketamine also significantly suppressed both LPS-induced and rhTNF-induced IL-6 and IL-8 production. In this study, we demonstrated that ketamine directly inhibits the production of proinflammatory cytokines such as TNF-alpha, IL-6, and IL-8 in human whole blood. IMPLICATIONS We found that ketamine suppressed lipopolysaccharide-induced tumor necrosis factor alpha, interleukin (IL)-6, and IL-8 production and recombinant human tumor necrosis factor-induced IL-6 and IL-8 production in human whole blood. Ketamine directly suppresses proinflammatory cytokine production.

Reliable Indices For The Determination Of Viability Of Grafted Liver Immediately After Orthotopic Transplantation Bile Flow Rate And Cellular Adenosine Triphosphate Level

One of the major problems accompanying liver transplantation is how to evaluate the viability of the grafted tissue at an early stage. The ability to assess immediate graft function would provide results useful in the determination of prognosis. The present study was undertaken to determine whether bile flow rates after liver transplantation were correlated with adenosine triphosphate levels and the survival of rats given transplants. In fresh-liver-transplanted rats, the one-week survival rate was 87%. The cellular ATP levels in the grafts decreased sharply prior to portal-venous declamping, but returned to nearly 80% of the normal level 4 hr after grafting, as did the total adenine nucleotide level and energy charge. When the grafts were subjected to warm ischemia for 15-min or 30-min periods prior to harvesting of the donor liver, the one-week survival rates decreased to 50% and 0%, respectively. In these cases, the levels of cellular ATP and bile secretion remained low and were proportional to the survival of the transplanted animals even 4 hr after transplantation. The relationship between the bile flow rates and the cellular ATP levels under various conditions revealed a good correlation, showing a saturation curve. The bile flow rates as well as the cellular ATP levels were therefore related to the survival rates of the transplanted animals. Thus it was shown in this experimental transplantation model that the monitoring of bile production after liver grafting is a useful indicator for assessing the extent of ischemic damage to the liver and for prognosis of the animal.

Surgical stress induces endotoxin hyporesponsiveness and an early decrease of monocyte mCD14 and HLA-DR expression during surgery.

It is generally accepted that major surgery is associated with severe alterations of the host-defense mechanisms. We investigated the effect of surgical stress on the immune system. Specifically, we studied the relationship between perioperative lipopolysaccharide (LPS) hyporesponsiveness and monocyte human leukocyte antigen-DR (HLA-DR) and CD14 expression during the perioperative period in 20 patients who underwent partial gastrectomy. This study demonstrated that surgical stress rapidly depressed monocyte mCD14 and HLA-DR expression in comparison with preanesthesia levels. Monocyte mCD14 expression recovered to preoperative levels on the first postoperative day, and monocyte HLA-DR expression recovered by the seventh postoperative day. Consistent with our previous study, LPS-induced tumor necrosis factor (TNF)-&agr; production ex vivo was significantly suppressed from the beginning of the operation. On the contrary, the plasma interleukin-10 concentration started to increase after the surgical incision was made. LPS hyporesponsiveness was least at the end of the operation and returned to preoperative levels on the first postoperative day. In conclusion, the present study demonstrated that LPS responsiveness, plasma interleukin-10 concentration, and monocytes mCD14 and HLA-DR expression altered from the early period of surgery. These alterations may be related to the impairment of the immune system during the perioperative period.

Role of interleukin-10 on hyporesponsiveness of endotoxin during surgery.

ObjectiveTo examine whether surgical stress causes blood cells to lose their responsiveness to endotoxin during surgery. DesignProspective case series. SettingA university hospital. PatientsSixteen volunteers classified as American Society of Anesthesiologists physical status I–II who were scheduled for elective distal partial gastrectomy. InterventionsWe studied nine patients who underwent elective distal partial gastrectomy. Blood samples for tumor necrosis factor (TNF) and interleukin (IL)-10 assay were obtained before anesthesia, preincision, 2 hrs and 4 hrs postincision, postextubation, and 24 hrs postincision. The rest of each blood sample was diluted with 5 volumes of endotoxin-free saline, incubated for 4 hrs in the presence of lipopolysaccharide (LPS), centrifuged to remove cells, and assayed for TNF. In another seven patients, antihuman IL-10 antibody was added into the diluted whole blood sample before LPS stimulation. Measurements and Main ResultsTNF activity was not detected in the blood of any patient throughout the study. In contrast, plasma cortisol and IL-10 levels increased rapidly during surgery (p < .01, p < .05, respectively). LPS-induced TNF activity in whole blood decreased significantly during surgery (p < .01) and recovered to control levels by 24 hrs postincision. The peak suppression of LPS-induced TNF and the peak value of plasma IL-10 levels occurred postextubation. Treatment with anti-IL-10 antibody partially restored the ability of LPS to induce TNF activity postextubation (p < .05). ConclusionsSurgical trauma rapidly induces a transient hyporesponsiveness of blood cells to endotoxin. Plasma IL-10, which increases during surgery, participates in this hyporesponsiveness.

Ketamine isomers suppress superantigen-induced proinflammatory cytokine production in human whole blood

PurposeTo investigate the efficacy of S(+)-ketamine and R(−)-ketamine on staphylococcal enterotoxin B (SEB)-induced tumour necrosis factor (TNF)-, interleukin (IL)-6, and IL-8 production in human whole bloodin vitro.MethodsAfter Ethics Committee approval and informed consent, blood samples were obtained from ten healthy volunteers and diluted with five volumes of RPMI 1640. After adding different doses of ketamine isomers (0–1000 μM), the blood was stimulated with SEB (10 ng·mL−1). After a six-hour incubation period, the plasma TNF-activity was determined by the L929 cell cytotoxic assay and IL-6 and IL-8 concentrations were measured using an enzyme-linked immunoassay.ResultsKetamine isomers significantly suppressed SEB-induced TNF-production at concentrations exceeding 50 μM. Ketamine isomers at concentrations exceeding 100 μM also significantly suppressed SEB-induced IL-6 production. Furthermore, ketamine isomers at concentrations exceeding 500 μM significantly suppressed SEB-induced IL-8 production. There were no significant differences between the suppressive effects of S(+)-ketamine and R(−)-ketamine on SEB-induced proinflammatory cytokine production.ConclusionThis study demonstrated that ketamine isomers suppressed SEB-induced TNF-, IL-6, and IL-8 production in human whole blood.RésuméObjectifVérifier l’efficacité de la S(+)-kétamine et de la R(−)-kétamine sur la production du facteur nécrosant des tumeurs (FNT)-a, de l’interleukine (IL)-6 et de l’IL-8, induits par l’entérotoxine B d’origine staphylococcique (EBS), dans le sang complet humain in vitro.MéthodeAprès avoir obtenu l’approbation du Comité d’éthique et le consentement éclairé des participants, nous avons recueilli des échantillons sanguins chez dix volontaires en santé et les avons dilué dans cinq volumes de RPMI 1640. Après l’addition de différentes doses d’isomères de kétamine (0–1000 μM), le sang a été stimulé avec l’EBS (10 ng·mL−1). À la suite d’une incubation de six heures, l’activité plasmatique de TNF-a a été déterminée par le dosage de la cytotoxicité cellulaire L929, et les concentrations d’IL-6 et d’IL-8 ont été mesurées au moyen d’un dosage immuno-enzymatique.RésultatsLes isomères de kétamine ont supprimé de façon significative la production du TNF-a induit par l’EBS à des concentrations dépassant 50 μM, la production d’IL-6 induite par l’EBS à des concentrations au delà de 100 μM et la production d’IL-8 induite par l’EBS à des concentrations de plus de 500 μM. Il n’y a pas eu de différence significative entre les effets suppresseurs de la S(+)-kétamine et de la R(−)-kétamine sur la production de cytokine pro-inflammatoire induite pas l’EBS.ConclusionCette étude démontre que les isomères de kétamine suppriment la production du FNT-a, d’IL-6 et d’IL-8, induits par l’EBS, dans le sang complet humain.

Downregulation of TLR4-dependent ATP production is critical for estrogen-mediated immunoprotection in Kupffer cells following trauma-hemorrhage.

Toll‐like receptor 4 (TLR4) mediates mitochondrial DNA (mtDNA) damage and biogenic responses. Mitochondrial transcription factor A (Tfam) is an essential regulator for mtDNA transcription and ATP production. Increased ATP levels were associated with normalization of immune function following trauma‐hemorrhage. Moreover, administration of 17β‐estradiol following trauma‐hemorrhage upregulates cardiac Tfam and ATP levels. We therefore hypothesized that the salutary effect of 17β‐estradiol on Kupffer cell function following trauma‐hemorrhage is mediated via negative regulation of TLR4, which downregulates iNOS, upregulates Tfam and mtDNA‐encoded gene cytochrome c oxidase I (mtCOI), and consequently increases cellular ATP levels. Male C3H/HeN, C3H/HeOuJ (intact TLR4), and C3H/HeJ (TLR4 mutant) mice were subjected to trauma‐hemorrhage (mean BP 35 ± 5 mmHg ∼90 min, then resuscitation) or sham operation. At the beginning of resuscitation, mice received 17β‐estradiol (25 µg/25 g) or vehicle intravenously and were sacrificed 2 h thereafter. Kupffer cell TLR4, iNOS, IL‐6 and TNF‐α production capacities were increased, and ATP, Tfam, and mtCOI levels were decreased following trauma‐hemorrhage. Administration of 17β‐estradiol following trauma‐hemorrhage prevented the increase in Kupffer cell TLR4, iNOS, and cytokine production. This was accompanied by normalized ATP, Tfam, and mtCOI levels. Furthermore, the decreased Kupffer cell ATP and mtCOI levels were not observed in TLR4 mutant mice following trauma‐hemorrhage. Taken together, these findings suggest that downregulation of TLR4‐dependent ATP production is critical to 17β‐estradiol‐mediated immunoprotection in Kupffer cells following trauma‐hemorrhage. J. Cell. Physiol. 211: 364–370, 2007.

The effects of dexmedetomidine on inflammatory mediators after cardiopulmonary bypass

Cardiac surgery with cardiopulmonary bypass is associated with the development of a systemic inflammatory response that can often lead to dysfunction of major organs. We hypothesised that the highly selective α2‐adrenergic agonist, dexmedetomidine, attenuates the systemic inflammatory response. Forty‐two patients were randomly assigned to receive dexmedetomidine or saline after aortic cross‐clamping). The mean (SD) levels of the nuclear protein plasma high‐mobility group box 1 increased significantly from 5.1 (2.2) ng.ml−1 during (16.6 (7.3) ng.ml−1) and after (14.3 (8.2) ng.ml−1) cardiopulmonary bypass in the saline group. In the dexmedetomidine group, the levels increased significantly only during cardiopulmonary bypass (4.0 (1.9) ng.ml−1 baseline vs 10.8 (2.7) ng.ml−1) but not after (7.4 (3.8) ng.ml−1). Dexmedetomidine infusion also suppressed the rise in mean (SD) interleukin‐6 levels after cardiopulmonary bypass (a rise of 124.5 (72.0) pg.ml−1 vs 65.3 (30.9) pg.ml−1). These suppressive effects of dexmedetomidine might be due to the inhibition of nuclear factor kappa B activation and suggest that intra‐operative dexmedetomidine may beneficially inhibit inflammatory responses associated with ischaemia‐reperfusion injury during cardiopulmonary bypass.

The effects of estrogen on various organs: therapeutic approach for sepsis, trauma, and reperfusion injury. Part 2: liver, intestine, spleen, and kidney

Several clinical studies show a gender dimorphism of immune and organ responsiveness in the susceptibility to and morbidity from shock, trauma, and sepsis. However, there are conflicting reports on the role of gender in outcomes. Animal studies of shock, trauma, and sepsis have confirmed that alterations in immune and organ functions are more markedly depressed in adult males and in ovariectomized and aged females. In this review, we discuss the effect of estrogen on liver, intestinal, splenic, and renal functions in an experimental model of sepsis, trauma, and reperfusion injury. To establish the role of gender in the outcome of these patients, more studies in clinical and experimental settings are required to determine whether gender-specific responses are global across the injuries or are observed in specific injury situations. Studies are also needed to delineate underlying mechanisms responsible for differences between males and females. The findings gained from the experimental studies will help in designing innovative therapeutic approaches for the treatment of sepsis, trauma, and reperfusion injury patients.

The effects of estrogen on various organs: therapeutic approach for sepsis, trauma, and reperfusion injury. Part 1: central nervous system, lung, and heart

Although several clinical studies show a gender dimorphism of immune and organ responsiveness in the susceptibility to and morbidity from shock, trauma, and sepsis, there are conflicting reports on the role of gender in outcomes. In contrast, results obtained from experimental studies clearly support the suggestion that gender plays a significant role in post-injury pathogenesis. Studies performed in a rodent model of trauma-hemorrhage have confirmed that alterations in immune and organ functions after trauma-hemorrhage are more markedly depressed in adult males and in ovariectomized and aged females; however, both are maintained in castrated males and in proestrus females. Moreover, the survival rate of proestrus females subjected to sepsis after trauma-hemorrhage is significantly higher than in age-matched males or ovariectomized females. In this respect, organ functions and immune responses are depressed in males with sepsis or trauma, whereas they are unchanged or are enhanced in females. This article reviews studies delineating the mechanism by which estrogen regulates cerebral nervous, lung, and heart systems in an experimental model of sepsis, trauma, or reperfusion injury.

Dexmedetomidine suppresses proinflammatory mediator production in human whole blood in vitro.

BACKGROUND: It has been demonstrated that proinflammatory mediators increase in patients with sepsis, trauma, and burns. These mediators are associated with the development of septic shock and organ dysfunction. Dexmedetomidine (DEX), a selective agonist of the [alpha]2‐adrenergic receptors, is used in intensive care units for sedation. However, it still remains unclear whether DEX administration has any effects on the production of proinflammatory mediators. In this study, we investigated the effects of DEX on lipopolysaccharide (LPS)–induced production of tumor necrosis factor [alpha], interleukin 6 (IL‐6), IL‐8, and high‐mobility group box 1 protein in human whole blood. METHODS: Human whole blood was cultured with LPS for up to 24 hours, and LPS‐induced proinflammatory mediator production was measured. Next, we tested the effect of DEX on whole blood proinflammatory mediator production. Human whole blood was cultured with LPS and various concentrations of DEX for 12 hours. Then, we investigated the influence of yohimbine, an antagonist of the [alpha]2‐adrenergic receptors, on the effects of DEX. The effect of DEX on necrosis factor [kappa]B (NF[kappa]B) activation was also investigated. RESULTS: DEX suppressed tumor necrosis factor [alpha], IL‐6, IL‐8, and high‐mobility group box 1 protein production in human whole blood. The suppressing effects of DEX on proinflammatory mediator production were reversed by yohimbine. The results suggested that the mechanism for the suppressive effects of DEX on proinflammatory mediator production is meditated via [alpha]2‐adrenergic receptors. These effects of DEX also include an inhibitory effect on NF[kappa]B activation. CONCLUSION: We demonstrate the suppressing effect of DEX on inflammatory mediator production in human whole blood after LPS stimulation. The mechanism for the suppressive effect of DEX on proinflammatory mediator production may be through the [alpha]2‐adrenergic receptors and NF[kappa]B inhibition.