Suefumi Aosasa

Mechanism of the inhibitory effect of protease inhibitor on tumor necrosis factor α production of monocytes

If the inflammatory response becomes excessive or uncontrolled by some stimuli, inappropriate inflammatory responses occur. Monocytes are extremely important cells for regulating the cytokine network and tumor necrosis factor alpha (TNFalpha) and interleukin- (IL) 10, which are mainly synthesized by monocytes, are representative cytokines that play a central role in the cytokine network. Protease inhibitors such as gabexate mesilate (GM) and ulinastatin (UTI) have been shown to have various beneficial effects by inhibiting the activation of leukocytes, but the mechanism for this has yet to be fully elucidated. In this study we investigated the mechanism of the inhibitory effect of protease inhibitors on the proinflammatory cytokine production of lipopolysaccharide- (LPS) stimulated monocytes. LPS-stimulated monocytes were treated with GM or UTI. The value of TNFalpha and IL-10 in the culture medium of monocytes was measured and each mRNA expression was assayed. The inhibitory effect of protease inhibitors on the activity of intracellular signal transduction pathways such as protein kinase C (PKC) and nuclear factor kappa B (NFkappaB) were also evaluated. GM decreased the TNFalpha production of LPS-stimulated monocytes as shown by the inhibition of mRNA expression and increased the IL-10 production of LPS-stimulated monocytes. GM also suppressed the NFkappaB activity of LPS-stimulated monocytes. UTI decreased the TNFalpha production of LPS-stimulated monocytes, but did not inhibit the TNFalpha mRNA expression. The present study shows that the inhibitory effect of GM on the TNFalpha production of activated human monocytes is mediated by the suppression of NFkappaB activation, while the mechanism of UTI inhibiting TNFalpha production of human monocytes may be due to the inhibition of either the translation or secretion of TNFalpha.

Activation of Monocytes and Endothelial Cells Depends on the Severity of Surgical Stress

Surgical injury not only induces a systemic endocrine-metabolic response but also influences the function of the leukocytes and endothelial cells leading to various systemic responses. These responses appear to depend on the severity of surgical stress, which differs according to the surgical procedures. In this study, we investigated the response of monocytes and endothelial cells, and the development of systemic inflammatory response syndrome (SIRS) in relation to the severity of surgical stress. The postoperative clinical course was evaluated between patients undergoing an esophagectomy (ER group) and a distal gastrectomy (DG group). The tumor necrosis factor α (TNFα) production of monocytes, the serum interleukin 6 (IL-6) levels, the CD11b expression on either monocytes or granulocytes, and the intercellular adhesion molecule-1 (ICAM-1) expression on human umbilical vein endothelial cells (HUVECs) stimulated with culture supernatants of monocytes were compared between the 2 groups. The development of SIRS was observed in all patients in the ER group, whereas no patients demonstrated SIRS in the DG group. The serum IL-6 levels, TNFα production of monocytes, and CD11b intensity on monocytes or granulocytes in the ER group were higher than those in the DG group. In the ER group, the ICAM-1 intensity on HUVECs with monocytes immediately after operation significantly increased compared with before the operation. In conclusion, both the CD11b expression on monocytes and the TNFα production of monocytes are considered to reflect the degree of surgical stress, and the activation of endothelial cells stimulated with these activated leukocytes may therefore lead to both tissue and organ injury.

Severe sepsis induces deficient interferon-gamma and interleukin-12 production, but interleukin-12 therapy improves survival in peritonitis

BACKGROUND After severe sepsis, there is an increase of Th2 cytokine and a decrease in Th1 cytokine that may account for impaired cellular immunity. The aim of this study is to evaluate the Th1, Th2 cytokine balance in the serum, peritoneal lavage fluid (PLF) and liver mononuclear cells (MNC) of experimental peritonitis mice, and determine the effect of interleukin-12 (IL-12), a cytokine stimulating Th1 cytokine production, when administered to septic mice. METHODS Experimental bacterial peritonitis mice was induced by cecal ligation and puncture (21-gauge needle, mild peritonitis) or cut (5 mm, severe peritonitis). Serum and PLF levels and liver MNC production of interferon (IFN)-gamma, IL-10, and IL-12 were measured after the procedure. Mild and severe peritonitis mice were treated intraperitoneally with recombinant IL-12 (r-IL-12) either 6 hours before or 6 and 24 hours after the procedure. The survival rates were then compared with nontreated mice. RESULTS Serum and PLF IFN-gamma, IL-12 levels in severe peritonitis mice were significantly lower than those in mild peritonitis mice at 6 and 12 hours after the procedure. On the other hand, serum and PLF IL-10 levels in severe peritonitis mice were significantly higher than those in mild peritonitis mice at 6 hours after the procedure. Furthermore, liver MNC IFN-gamma production in severe peritonitis mice was significantly higher than that in mild peritonitis mice at 6 hours after the procedure, but liver MNC IL-12 production in severe peritonitis mice was significantly lower than that in mild peritonitis mice at 12 hours after the procedure. Severe peritonitis mice treated with r-IL-12 at 6 hours before the procedure improved survival rate, and mild peritonitis mice treated with r-IL-12 at 24 hours after the procedure showed significantly improved survival rates. CONCLUSIONS Change in the Th1, Th2 cytokine balance in peritonitis mice might induce a shift toward a Th2 dominant phenotype according to the severity of peritonitis, and the capacity to produce IFN-gamma and IL-12 by liver MNC is reduced. Therapies designed to augment the production of Th1 cytokines, such as IL-12, may thus prove to be beneficial in the treatment of severe sepsis after peritonitis.

Effects of a protease inhibitor on reduction of surgical stress in esophagectomy

OBJECTIVE To evaluate the efficacy of gabexate mesilate (GM) in reducing surgical stress after esophagectomy. METHODS In a prospective, randomized, clinical study, 11 patients with squamous cell carcinoma of the esophagus were randomly assigned to two groups: 5 patients were continuously administered gabexate mesilate 1.5 mg/kg per hour from the beginning of anesthesia until the third postoperative day (preop GM group); and 6 patients were administered gabexate mesilate 1.5 mg/kg per hour continuously from the end of surgery and for the same postoperative period (postop GM group). Blood samples were taken from all patients before surgery, immediately after it, and 3 days after surgery. Serum interleukin-6 (IL-6) level, tumor necrosis factor-alpha (TNF-alpha) production, and Mac-1 antigen expression of peripheral blood monocytes were measured. Clinical courses of patients in the two groups were compared. RESULTS Time courses of serum IL-6 levels in the preop GM group were significantly lower than those in the postop GM group. Ex vivo TNF-alpha production by lipopolysaccharide (LPS) stimulated monocyte was much higher than that by monocyte without LPS stimulation. Gabexate mesilate showed a little inhibition of TNF-alpha production by monocyte without LPS stimulation. On the other hand, gabexate mesilate significantly inhibited TNF-alpha production by LPS stimulated monocyte. Mac-1 antigen expression by monocyte immediately after operation in the preop GM group was significantly lower than that in the postop GM group. Duration of systemic inflammatory response syndrome was significantly shorter in the preop GM group than in the postop GM group. CONCLUSIONS Reduction of systemic inflammatory response syndrome duration after esophagectomy by the continuous administration of gabexate mesilate started before operation may be through the suppression of TNF-alpha production capacity and Mac-1 expression on monocytes immediately after operation, and to suppression of increase in serum IL-6 level.

Increased Monocyte Activation in Elderly Patients after Surgical Stress

Objective: To investigate age-related changes in the host response to surgical stress. The clinical course, serum interleukin-6 (IL-6) levels, monocyte production of tumor necrosis factor-α (TNF-α), and monocyte expression of CD11b/CD18 were used as markers of the systemic response. Methods: Patients with gastric cancer, undergoing distal gastrectomy were divided into 2 groups: >75 years of age (elderly group) and ≤75 years of age (young group). Serum IL-6 levels, TNF-α production and CD11b/CD18 expression by monocytes, and the postoperative clinical course were compared between the 2 groups. Results: TNF-α production by lipopolysaccharide-stimulated monocytes and CD11b/CD18 expression on monocytes after surgical stress were significantly higher in the elderly than in the young group. Moreover, serum IL-6 levels on the first postoperative day in the elderly group were significantly higher than those in the young group. The incidence and duration of systemic inflammatory response syndrome (SIRS) were significantly greater in the elderly than in the young group. Conclusions: The activation of monocytes and hypercytokinemia occur readily after surgical stress in the elderly and may therefore contribute to SIRS and increased susceptibility to postoperative complications.

Acyl-CoA:cholesterol acyltransferase 1 mediates liver fibrosis by regulating free cholesterol accumulation in hepatic stellate cells

BACKGROUND & AIMS Acyl-coenzyme A: cholesterol acyltransferase (ACAT) catalyzes the conversion of free cholesterol (FC) to cholesterol ester, which prevents excess accumulation of FC. We recently found that FC accumulation in hepatic stellate cells (HSCs) plays a role in progression of liver fibrosis, but the effect of ACAT1 on liver fibrosis has not been clarified. In this study, we aimed to define the role of ACAT1 in the pathogenesis of liver fibrosis. METHODS ACAT1-deficient and wild-type mice, or Toll-like receptor 4 (TLR4)(-/-)ACAT1(+/+) and TLR4(-/-)ACAT1(-/-) mice were subjected to bile duct ligation (BDL) for 3 weeks or were given carbon tetrachloride (CCl4) for 4 weeks to induce liver fibrosis. RESULTS ACAT1 was the major isozyme in mice and human primary HSCs, and ACAT2 was the major isozyme in mouse primary hepatocytes and Kupffer cells. ACAT1 deficiency significantly exaggerated liver fibrosis in the mouse models of liver fibrosis, without affecting the degree of hepatocellular injury or liver inflammation, including hepatocyte apoptosis or Kupffer cell activation. ACAT1 deficiency significantly increased FC levels in HSCs, augmenting TLR4 protein and downregulating expression of transforming growth factor-β (TGFβ) pseudoreceptor Bambi (bone morphogenetic protein and activin membrane-bound inhibitor), leading to sensitization of HSCs to TGFβ activation. Exacerbation of liver fibrosis by ACAT1 deficiency was dependent on FC accumulation-induced enhancement of TLR4 signaling. CONCLUSIONS ACAT1 deficiency exaggerates liver fibrosis mainly through enhanced FC accumulation in HSCs. Regulation of ACAT1 activities in HSCs could be a target for treatment of liver fibrosis.

A clinical study of the effectiveness of oral glutamine supplementation during total parenteral nutrition : Influence on mesenteric mononuclear cells

Bacterial translocation (BT) is a well-known insult during total parenteral nutrition (TPN) and a high incidence of morbidity has been reported in septic patients receiving TPN. Inflammatory cytokines were shown to play an important role in the pathogenesis of critical complications following sepsis. Previous studies have indicated that supplementation of TPN with glutamine is effective in preventing BT in animals, but its effectiveness in humans is unclear. The aim of this study was to determine the effectiveness of oral glutamine supplementation to patients receiving TPN in suppressing cytokine production of mesenteric blood mononuclear cells (M-MNC). Fifteen colorectal cancer patients were divided into 3 groups according to preoperative nutrition management. (1) TPN group: TPN with conventional glutamine-free amino acid solution. (2) Gln group: TPN with oral glutamine supplementation of 30 g/d. (3) CONTROL GROUP: oral intake of normal food. M-MNC were obtained immediately after laparotomy and tumor necrosis factor-alpha (TNF-alpha) and interleukin-10 (IL-10) production of M-MNC was evaluated with or without lipopolysaccharide (LPS) stimulation. TNF-alpha and IL-10 production by LPS-stimulated M-MNC was increased in the TPN group and suppressed in the Gln group. In conclusion, oral glutamine supplementation to patients with TPN was shown to be effective for the prevention of M-MNC activation to avoid excessive production of cytokines.

Prognostic value of poorly differentiated clusters in the primary tumor in patients undergoing hepatectomy for colorectal liver metastasis

BACKGROUND This study aimed to determine the prognostic value of a novel grading system based on the histologic assessment of poorly differentiated clusters (PDCs) in the primary lesions in patients with hepatectomy for colorectal liver metastasis (CRLM). Preoperative survival predictors for CRLM are required to determine candidates for perioperative chemotherapy who would otherwise have a poor prognosis. METHODS In total, 411 consecutive patients undergoing curative resection of primary colorectal cancers and metastatic liver lesions at 2 institutions were enrolled. Cancer clusters comprising ≥ 5 cancer cells, lacking a gland-like structure, were defined as PDCs and quantifiably graded. RESULTS According to PDCs, 65, 127, and 219 patients were classified as being grades (G)1, G2, and G3, respectively. PDCs were associated with T and N stages and tumor budding in primary tumor, extrahepatic disease, and serum CEA levels (P ≤ .0001-.045), but not with the number and size of liver metastasis. PDC grade significantly influenced recurrence rate in extrahepatic sites, including the lung and peritoneum (P < .0001). The 2-year disease-free survival after hepatectomy was 64.6%, 38.8%, and 22.4% in G1, G2, and G3, respectively. Based on multivariate analysis, PDC grade was selected as an independent prognostic factor together with other conventional factors such as extrahepatic disease and the number of liver metastasis. CONCLUSION PDC grade in primary lesions is a novel potent prognostic indicator in CRLM independent of the anatomic extent of disease. Notably, PDC grade can bias survival rates in clinical studies targeting perioperative chemotherapy in CRLM.

Mouse CD11b+Kupffer Cells Recruited from Bone Marrow Accelerate Liver Regeneration after Partial Hepatectomy

TNF and Fas/FasL are vital components, not only in hepatocyte injury, but are also required for hepatocyte regeneration. Liver F4/80+Kupffer cells are classified into two subsets; resident radio-resistant CD68+cells with phagocytic and bactericidal activity, and recruited radio-sensitive CD11b+cells with cytokine-producing capacity. The aim of this study was to investigate the role of these Kupffer cells in the liver regeneration after partial hepatectomy (PHx) in mice. The proportion of Kupffer cell subsets in the remnant liver was examined in C57BL/6 mice by flow cytometry after PHx. To examine the role of CD11b+Kupffer cells/Mφ, mice were depleted of these cells before PHx by non-lethal 5 Gy irradiation with or without bone marrow transplantation (BMT) or the injection of a CCR2 (MCP-1 receptor) antagonist, and liver regeneration was evaluated. Although the proportion of CD68+Kupffer cells did not significantly change after PHx, the proportion of CD11b+Kupffer cells/Mφ and their FasL expression was greatly increased at three days after PHx, when the hepatocytes vigorously proliferate. Serum TNF and MCP-1 levels peaked one day after PHx. Irradiation eliminated the CD11b+Kupffer cells/Mφ for approximately two weeks in the liver, while CD68+Kupffer cells, NK cells and NKT cells remained, and hepatocyte regeneration was retarded. However, BMT partially restored CD11b+Kupffer cells/Mφ and recovered the liver regeneration. Furthermore, CCR2 antagonist treatment decreased the CD11b+Kupffer cells/Mφ and significantly inhibited liver regeneration. The CD11b+Kupffer cells/Mφ recruited from bone marrow by the MCP-1 produced by CD68+Kupffer cells play a pivotal role in liver regeneration via the TNF/FasL/Fas pathway after PHx.

Histologic categorization of fibrotic cancer stroma in the primary tumor is an independent prognostic index in resectable colorectal liver metastasis.

Although the molecular mechanism of desmoplastic reaction (DR) for providing aggressive tumor characteristics is increasingly recognized, the prognostic role of DR has not been investigated in colorectal liver metastasis (CRLM). A pathologic review of 412 patients who underwent hepatectomy for CRLM at 2 independent institutions was conducted. DR in primary tumors was classified as mature, intermediate, or immature on the basis of the existence of keloid-like collagen and myxoid stroma–distinctive histologic products of extracellular matrix remodeling. With respect to DR, 137, 122, and 153 patients were classified as mature, intermediate, and immature, respectively. Immature DRs were associated with higher T and N stages, higher primary tumor grade, synchronous and larger size of liver metastasis, and extrahepatic disease (P⩽0.0001 to 0.002). DR significantly influenced the rate of recurrence in extrahepatic sites, including the lung, peritoneum, and local region in the primary tumor (P⩽0.0001 to 0.03), rather than the remnant liver. Five-year overall survival rates after hepatectomy were the highest in the mature group (58.9%), followed by intermediate (42.1%) and immature (26.7%) groups. A significant prognostic impact of DR was observed in subset analyses for institutions, primary tumor location, and timing and number of liver metastases. Multivariate analysis revealed that DR was an independent prognostic factor along with T stage of the primary tumor, size of liver metastasis, and extrahepatic disease. Characterizing DR in the primary tumor on the basis of histologic products of cancer-associated fibroblasts is valuable in evaluating prognostic outcome after hepatectomy in CRLM patients.