Masaharu Oishi

α-Lipoic Acid Prevents the Induction of iNOS Gene Expression Through Destabilization of Its mRNA in Proinflammatory Cytokine-Stimulated Hepatocytes

Background/Aimsα-Lipoic acid (α-LA) has been reported to reduce ischemia–reperfusion injury (IRI). Proinflammatory cytokines stimulate the induction of inducible nitric oxide synthase (iNOS) gene expression, leading to excess production of NO and resulting in liver injury including IRI. We hypothesized that inhibition of iNOS induction underlies the protective effects of α-LA on the liver. The objective was to investigate whether α-LA directly influences iNOS induction in cultured hepatocytes, which is used as a simple in vitro injury model, and the mechanism involved.MethodsPrimary cultured rat hepatocytes were treated with interleukin (IL)-1β in the presence or absence of α-LA. The induction of iNOS and NO production and its signal were analyzed.Resultsα-LA inhibited the expression of iNOS mRNA and protein dose- and time-dependently, resulting in decreases in NO production. α-LA had no effects on the degradation of IκB proteins and activation of NF-κB. In contrast, α-LA inhibited the upregulation of type I IL-1 receptor stimulated by IL-1β, although α-LA had no effect on Akt activation. Transfection experiments with iNOS promoter-luciferase constructs revealed that α-LA had no effect on the transactivation of the iNOS promoter, but decreased the stabilization of iNOS mRNA. Further, α-LA inhibited the expression of an iNOS gene antisense-transcript, which is involved in iNOS mRNA stability.ConclusionsResults indicate that α-LA inhibits the induction of iNOS gene expression at a posttranscriptional step via iNOS mRNA stabilization, rather than promoter activation. It may provide useful therapeutic effects through the suppression of iNOS induction involved in liver injury.

Peroxidation of n-3 Polyunsaturated Fatty Acids Inhibits the Induction of iNOS Gene Expression in Proinflammatory Cytokine-Stimulated Hepatocytes

Eicosapentaenoic acid and docosahexaenoic acid (EPA/DHA), n-3 polyunsaturated fatty acids (PUFAs), have a variety of biological activities including anti-inflammatory and anticancer effects. We hypothesized that their peroxidized products contributed in part to anti-inflammatory effects. In the liver, the production of nitric oxide (NO) by inducible nitric oxide synthase (iNOS) has been implicated as one of the factors in hepatic inflammation and injury. We examined whether the peroxidation of EPA/DHA influences the induction of iNOS and NO production in proinflammatory cytokine-stimulated cultured hepatocytes, which is in vitro liver inflammation model. Peroxidized EPA/DHA inhibited the induction of iNOS and NO production in parallel with the increased levels of their peroxidation, whereas unoxidized EPA/DHA had no effects at all. Peroxidized EPA/DHA reduced the activation of transcription factor, NF-κB, and the expression of the iNOS antisense transcript, which are involved in iNOS promoter transactivation (mRNA synthesis) and its mRNA stabilization, respectively. These findings demonstrated that peroxidized products of EPA/DHA suppressed the induction of iNOS gene expression through both of the transcriptional and posttranscriptional steps, leading to the prevention of hepatic inflammation.

Active hexose correlated compound inhibits the expression of proinflammatory biomarker iNOS in hepatocytes.

Background/Aims: Excess production of nitric oxide (NO) by inducible nitric oxide synthase (iNOS) has been implicated as proinflammatory biomarker in liver injury. The application of active hexose correlated compound (AHCC) as a functional food in complementary and alternative medicine has increased. The possibility that AHCC might inhibit iNOS induction was investigated as a potential liver-protective effect. Methods: Hepatocytes were isolated from rats by collagenase perfusion and cultured. Primary cultured hepatocytes were treated with interleukin-1β in the presence or absence of AHCC-sugar fraction (AHCC-SF). Results and Conclusion: AHCC-SF inhibited the production of NO and reduced expressions of iNOS mRNA and its protein. AHCC-SF had no effects on either IĸB degradation or nuclear factor-ĸB (NF-ĸB) activation. In contrast, AHCC-SF inhibited the upregulation of type I interleukin-1 receptor (IL-1RI) through the inhibition of Akt phosphorylation. Transfection experiments with iNOS promoter-luciferase constructs revealed that AHCC-SF reduced the levels of iNOS mRNA at both promoter transactivation and mRNA stabilization steps. AHCC-SF inhibited the expression of iNOS gene antisense transcript, which is involved in iNOS mRNA stabilization. These findings demonstrate that AHCC-SF suppresses iNOS gene expression through a IĸB/NF-ĸB-independent but Akt/IL-1RI-dependent pathway, resulting in the reduction of NO production. AHCC-SF may have therapeutic potential for various liver injuries.

Japanese Herbal Medicine Hochuekkito Inhibits the Expression of Proinflammatory Biomarker, Inducible Nitric Oxide Synthase, in Hepatocytes

Hochuekkito (TJ-41) is used for the treatment of complaints in patients with general fatigue. However, there is little scientific evidence to demonstrate the liver-protective effects of TJ-41. In the inflamed liver, proinflammatory cytokines stimulate the induction of inducible nitric oxide synthase (iNOS). Over-production of NO by iNOS has been implicated as a factor in liver injury. We examined proinflammatory cytokine-stimulated hepatocytes as a simple in vitro injury model to determine liver-protective effects of TJ-41. The objective was to investigate whether TJ-41 influences iNOS induction and to determine its mechanism. Primary cultured rat hepatocytes were treated with interleukin (IL)-1β in the presence or absence of TJ-41. The induction of iNOS and its signaling pathway were analyzed. IL-1β produced increased levels of NO. This effect was inhibited by TJ-41, which exerted its maximal effects at 6 mg/ml. TJ-41 decreased the levels of iNOS protein and its mRNA expression. Experiments with nuclear extracts revealed that TJ- 41 inhibited the translocation of NF-κB to the nucleus and its DNA binding. TJ-41 also inhibited the activation of Akt, resulting in the reduction of type I IL-1 receptor mRNA and protein expression. Transfection experiments demonstrated that TJ-41 suppressed iNOS induction by the inhibition of promoter transactivation and mRNA stabilization. TJ-41 reduced the expression of an iNOS gene antisense-transcript, which is involved in iNOS mRNA stability. Results indicate that TJ-41 inhibits the induction of iNOS at both transcriptional and post-transcriptional steps, leading to the prevention of NO production. TJ-41 may have therapeutic potential for various liver injuries through the suppression of iNOS induction.

Solitary fibrous tumor of soft tissue: a case report and immunohistochemical study

A case of solitary fibrous tumor (SFT) arising in the soft tissue of the left inguinal region is reported. A 57-year-old Japanese woman presented with a nonadherent, well-defined, oval mass that was 2 × 3 cm in diameter and located in the inguinal soft tissue. Microscopic evaluation showed proliferation of spindle-shaped, fibroblast-like cells by the coexistence of hypo- and hypercellular areas with mast cell infiltration separated by hemangiopericytoma-like blood vessels. Immunohistochemistry revealed strong expression of CD34 and CD99 in the fibroblast-like cells, supporting the diagnosis of SFT. Although the patient was free of symptoms such as hypoglycemia, immunoreactive insulin-like growth factor (IGF)-II was localized in the socalled Golgi area of the spindle-shaped cells. In conclusion, immunoreactive IGF-II was detected in SFT that was not associated with hypoglycemia.

Fluvastatin inhibits the induction of inducible nitric oxide synthase, an inflammatory biomarker, in hepatocytes.

Statins (3‐hydroxy‐3‐methylglutaryl coenzyme A [HMG‐CoA] reductase inhibitors), which were originally designed to lower plasma cholesterol levels, are increasingly recognized as anti‐inflammatory agents. In the inflamed liver, pro‐inflammatory cytokines stimulate the induction of inducible nitric oxide synthase (iNOS). Overproduction of NO by iNOS has been implicated as a factor in liver injury. We examined pro‐inflammatory cytokine‐stimulated hepatocytes as a simple in vitro injury model to determine liver‐protective effects of statins. We hypothesized that statins are involved in the downregulation of iNOS, resulting in decreased hepatic inflammation.

Japanese Kampo Medicine, Ninjinyoeito, Inhibits the Induction of iNOS Gene Expression in Proinflammatory Cytokine-Stimulated Hepatocytes

This work was carried out in collaboration between all authors. Authors YT, HM, MO and RN managed the analyses of the study. Author YT performed the statistical analysis, wrote the protocol and wrote the first draft of the manuscript. Authors MK, KT, MN, TO and AHK managed the coordination of the study. Authors MK, TO and MN conceived the study and participated in its design. This work was carried out in collaboration between all authors. All authors read and approved the final manuscript.

Adenosine, a hepato-protective component in active hexose correlated compound: Its identification and iNOS suppression mechanism

Supplementation of active hexose correlated compound (AHCC) improved the prognosis of postoperative hepatocellular carcinoma patients. Excess production of nitric oxide (NO) by inducible NO synthase (iNOS) is an inflammatory biomarker in liver injury. AHCC suppressed iNOS induction in hepatocytes, suggesting that AHCC has a potential liver-protective effect. However, the active component in AHCC responsible for NO suppressive activities has not been identified. The objective of this study was to identify this NO suppressive component and to investigate its mechanisms of action. AHCC was subjected to fractionation by cation exchanger, size exclusion chromatography, and normal- and reversed-phase HPLC. Aliquots of the fractions were added to primary cultured rat hepatocytes stimulated with interleukin (IL)-1β, and NO production was assayed. By activity-guided fractionation and electron spray ionization mass spectrometry analysis, adenosine was identified as one of the NO suppressive components in AHCC. Adenosine inhibited NO production, and reduced the expression of iNOS protein and mRNA. It had no effects on IκB degradation, but it inhibited NF-κB activation. Adenosine also inhibited the upregulation of type I IL-1 receptor (IL-1RI). Experiments with iNOS promoter-luciferase constructs revealed that adenosine decreased the levels of iNOS mRNA at the promoter transactivation and mRNA stabilization steps. Adenosine decreased the expression of the iNOS gene antisense transcript, which is involved in iNOS mRNA stability. Adenosine in AHCC suppressed iNOS induction by blocking NF-κB activation and the upregulation of the IL-1RI pathways, resulting in the inhibition of NO production.

Laparoscopic reduced port surgery for schwannoma of the sigmoid colon: A case report

A 74‐year‐old woman who developed schwannoma of the sigmoid colon was referred to our hospital for colonography to determine the cause of her stool occult blood. Colonoscopy revealed a submucosal tumor, which measured 3 cm in diameter, in the sigmoid colon. Endoscopic ultrasonography revealed a low echoic, homogeneous and demarcated submucosal tumor that continued into the fourth layer of the colonic wall. Gastrointestinal stromal, myogenic or neurogenic tumor was suspected, and thus, laparoscopic sigmoidectomy was carried out. We used two ports during the operation, a SILS Port in the umbilical region and a 12‐mm port in the right lower abdominal wall, and performed sigmoidectomy with D2 lymph node dissection. Histological findings revealed spindle‐like tumor cells with multiform nuclei. The tumor was diagnosed by immunostaining as benign schwannoma of the sigmoid colon. The conventional surgical treatment for schwannoma of the digestive tract is partial resection, but if preoperative diagnosis is unknown, radical resection with lymphadenectomy is acceptable for submucosal tumors in the digestive tract. In this case, laparoscopic reduced port surgery using only one or two ports may be more feasible and beneficial with regard to cosmesis and reduced postoperative pain than conventional laparoscopic colectomy.

Elental® amino acid component has protective effects on primary cultured hepatocytes and a rat model of acute liver injury

Amino acids can exert protective effects on the liver either when administered as a medication or following an operation. In this study, we examined the protective effects of amino acids on the liver using in vitro and in vivo models by studying their influence on the induction of inducible nitric oxide synthase (iNOS) and nitric oxide production as a liver injury marker in cultured hepatocytes and liver-protective effects in d-galactosamine and lipopolysaccharide (GalN/LPS)-treated rats, respectively. Primary cultured rat hepatocytes were treated with interleukin (IL)-1β in the presence or absence of Elental® amino acid component (EleAA; 17 amino acids). Rats were pretreated with either EleAA or a diet containing selected amino acids followed by GalN/LPS injection. Survival rate and mRNA expression were analyzed. EleAA inhibited iNOS induction through reduction of mRNA synthesis and stability in cultured hepatocytes, indicating prevention of liver injury, but did not show a liver-protective effect in GalN/LPS rats. Among EleAA, Lys, Trp, His, and Arg (4AA) markedly decreased nitric oxide production and inhibited nuclear factor-κB (NF-κB) activation. In GalN/LPS rats, 4AA (3% of each amino acid in diet) increased survival rate by 50% and decreased mRNA expression of iNOS, tumor necrosis factor-α, and cytokine-induced neutrophil chemoattractant-1 in the liver. 4AA reduced NF-κB activation induced by GalN/LPS. 4AA inhibited the expression of inflammatory mediators, in part through inhibition of NF-κB activation in cultured hepatocytes and GalN/LPS-treated rats. The results suggest that EleAA has therapeutic potential for organ injuries including liver.