Role of G protein-coupled receptor kinase 2 in oxidative and nitrosative stress-related neurohistopathological changes in a mouse model of sepsis-associated encephalopathy.

Sepsis-associated encephalopathy (SAE), characterized as diffuse brain dysfunction and neurological manifestations secondary to sepsis, is a common complication in critically ill patients and can give rise to poor outcome, but understanding the molecular basis of this disorder remains a major challenge. Given the emerging role of G protein-coupled receptor 2 (GRK2), first identified as a G protein-coupled receptor (GPCR) regulator, in the regulation of non-G protein-coupled receptor-related molecules contributing to diverse cellular functions and pathology, including inflammation, we tested the hypothesis that GRK2 may be linked to the neuropathogenesis of SAE. When mouse MG6 microglial cells were challenged with lipopolysaccharide (LPS), GRK2 cytosolic expression was highly up-regulated. The ablation of GRK2 by small interfering RNAs (siRNAs) prevented an increase in intracellular reactive oxygen species generation in LPS-stimulated MG6 cells. Furthermore, the LPS-induced up-regulation of inducible nitric-oxide synthase expression and increase in nitric oxide production were negated by GRK2 inhibitor or siRNAs. However, GRK2 inhibition was without effect on overproduction of tumor necrosis factor-α, interleukin (IL)-6, and IL-1ß in LPS-stimulated MG cells. In mice with cecal ligation and puncture-induced sepsis, treatment with GRK2 inhibitor reduced high levels of oxidative and nitrosative stress in the mice brains, where GRK2 expression was up-regulated, alleviated neurohistological damage observed in cerebral cortex sections, and conferred a significant survival advantage to CLP mice. Altogether, these results uncover the novel role for GRK2 in regulating cellular oxidative and nitrosative stress during inflammation and suggest that GRK2 may have a potential as an intriguing therapeutic target to prevent or treat SAE.

Inhibition of histone deacetylases protects septic mice from lung and splenic apoptosis.

BACKGROUND: Epigenetic programming, dynamically regulated by histone acetylation, may play a key role in the pathophysiology of sepsis. We examined whether histone deacetylase (HDAC) can contribute to sepsis-associated inflammation and apoptosis. MATERIALS AND METHODS: Polymicrobial sepsis was induced by cecal ligation and puncture (CLP) in BALB/c mice. An intraperitoneal injection of CG200745 (10 mg/kg), a novel broad-spectrum HDAC inhibitor, or valproic acid (500 mg/kg), a predominant inhibitor of class I HDACs, was given 3 h before surgery. RESULTS: HDAC1, HDAC2, and HDAC3 protein levels were decreased in lungs after CLP. Furthermore, CLP-induced sepsis increased both histone H3 and H4 acetylation levels in lungs. When CG200745 was given, apoptosis induction was strongly suppressed in lungs and spleens of septic mice. This antiapoptotic effect of CG200745 was not accompanied by upregulation of antiapoptotic and downregulation of proapoptotic Bcl-2 family member proteins. Treatment with CG200745 failed to inhibit elevated levels of serum cytokines and prevent lung inflammation in septic mice. Valproic acid also showed antiapoptotic but not anti-inflammatory effects in septic mice. CONCLUSIONS: These findings imply that HDAC inhibitors are a unique agent to prevent cell apoptosis in sepsis at their doses that do not improve inflammatory features, indicating that septic inflammation and apoptosis may not necessarily be essential for one another's existence. This study also represents the first report that CLP-induced sepsis downregulates HDACs. Nevertheless, the data with HDAC inhibitors suggest that imbalance in histone acetylation may play a contributory role in expression or repression of genes involved in septic cell apoptosis.

Olprinone and colforsin daropate alleviate septic lung inflammation and apoptosis through CREB-independent activation of the Akt pathway.

Olprinone, a specific phosphodiesterase III inhibitor, and corforsin daropate, a direct adenylate cyclase activator, are now being used in critical conditions. We investigated whether their therapeutic use provides protection against septic acute lung injury (ALI) and mortality. Polymicrobial sepsis was induced by cecal ligation and puncture (CLP) in BALB/c mice. Olprinone or colforsin daropate was continuously given through an osmotic pump that was implanted into the peritoneal cavity immediately following CLP. These treatments prevented the ALI development in CLP mice, as indicated by the findings that severe hypoxemia, increased pulmonary vascular permeability, and histological lung damage were strikingly remedied. Furthermore, continued administration of olprinone or colforsin daropate suppressed apoptosis induction in septic lungs and improved the survival of CLP mice. Olprinone and corforsin daropate enhanced Akt phosphorylation in septic lungs. Wortmannin, which inhibits the Akt upstream regulator phosphatidylinositol 3-kinase, abrogated the protective effects of olprinone and corforsin daropate on sepsis-associated lung inflammation and apoptosis. In vivo transfection of cyclic AMP response element binding protein (CREB) decoy oligodeoxynucleotide failed to negate the abilities of these agents to increase Akt phosphorylation and to inhibit IκBα degradation in septic lungs. These results demonstrate for the first time that CREB-independent Akt-mediated signaling is a critical mechanism contributing to the therapeutic effects of olprinone and corforsin daropate on septic ALI. Moreover, our data also suggest that these cyclic AMP-related agents, by blocking both nuclear factor-κB activation and apoptosis induction, may represent an effective therapeutic approach to the treatment of the septic syndrome.

[Examination of acute kidney injury after abdominal aortic aneurysm surgery].

BACKGROUND: Either suprarenal or infrarenal aortic clamping markedly reduces renal blood flow. This aortic clamping may cause postoperative acute kidney injury(AKI). METHODS: Fifty-four patients undergoing open abdominal aortic aneurysm (AAA) surgery were included in a retrospective study. Postoperative AKI defined as an absolute increase in serum creatinine (Cre) of more than or equal to 0.3 mg x dl(-1) or an increase in Cre of more than or equal to 50% within 48 hours after the end of the procedure. RESULTS: Thirteen patients developed AKI, but none of them required dialysis. The patients with AKI had higher preoperative Cre, longer operation, longer clamp time and more use of diuretics intra- and postoperatively. CONCLUSIONS: AKI occurred in 24.1% of patients undergoing AAA surgery. Risk factors for AKI were preoperative Cre, operation time, clamp time and use of diuretics.

[The influence of remifentanil on intra- and postoperative drug cost].

BACKGROUND: Intraoperative use of remifentanil requires much more analgesics postoperatively. Moreover, remifentanil causes intraoperative hypotension and bradycardia. METHODS: The objectives are to compare intra- and post-operative drug cost between patients who received remifentanil (Group R, n = 72) and those who received fentanyl (Group F, n = 66) during laparoscopic cholecystectomy retrospectively. RESULTS: The baseline demographics were similar between the two groups. Intraoperative drug costs were 7,782 +/- 1,579 yen in Group R and 6,235 +/- 1,037 yen in Group E Postoperative drug costs were 364 +/- 521 yen in Group R and 146 +/- 153 yen in Group E Total drug costs were 8,167 +/- 1,607 yen in Group R and 6,381 +/- 1,042 yen in Group E These reached statistical significance (P < 0.01). Length of hospital stay (days) between the two groups were comparable. CONCLUSIONS: Remifentanil anesthesia requires much more intra- and post-operative drug cost than fentanyl anesthesia for laparoscopic cholecystectomy.