Naoto Kitamura

Tumour necrosis factor α signalling through activation of Kupffer cells plays an essential role in liver fibrosis of non-alcoholic steatohepatitis in mice

Background: While tumour necrosis factor α (TNF-α) appears to be associated with the development of non-alcoholic steatohepatitis (NASH), its precise role in the pathogenesis of NASH is not well understood. Methods: Male mice deficient in both TNF receptors 1 (TNFR1) and 2 (TNFR2) (TNFRDKO mice) and wild-type mice were fed a methionine and choline deficient (MCD) diet or a control diet for eight weeks, maintaining isoenergetic intake. Results: MCD dietary feeding of TNFRDKO mice for eight weeks resulted in attenuated liver steatosis and fibrosis compared with control wild-type mice. In the liver, the number of activated hepatic Kupffer cells recruited was significantly decreased in TNFRDKO mice after MCD dietary feeding. In addition, hepatic induction of TNF-α, vascular cell adhesion molecule 1, and intracellular adhesion molecule 1 was significantly suppressed in TNFRDKO mice. While in control animals MCD dietary feeding dramatically increased mRNA expression of tissue inhibitor of metalloproteinase 1 (TIMP-1) in both whole liver and hepatic stellate cells, concomitant with enhanced activation of hepatic stellate cells, both factors were significantly lower in TNFRDKO mice. In primary cultures, TNF-α administration enhanced TIMP-1 mRNA expression in activated hepatic stellate cells and suppressed apoptotic induction in activated hepatic stellate cells. Inhibition of TNF induced TIMP-1 upregulation by TIMP-1 specific siRNA reversed the apoptotic suppression seen in hepatic stellate cells. Conclusions: Enhancement of the TNF-α/TNFR mediated signalling pathway via activation of Kupffer cells in an autocrine or paracrine manner may be critically involved in the pathogenesis of liver fibrosis in this NASH animal model.

Predictors to assess non-sentinel lymph node status in breast cancer patients with sentinel lymph node metastasis

Abstract:  The next step of sentinel lymph node biopsy (SLNB) in breast cancer is to determine which patients need axillary lymph node dissection (ALND) following a positive SLNB. A prospective database of 239 patients who underwent SLNB followed by complete ALND at Keio University Hospital from January 2001 to June 2005 was reviewed. A total of 131 patients with one or more positive sentinel lymph nodes (SLNs) were further analyzed. A univariate analysis showed a significant correlation between non‐SLN involvement and lymphatic invasion, vascular invasion, number of tumor‐involved SLNs, radioactivity of SLNs, and size of SLN metastasis (p = 0.0002, p = 0.004, p = 0.006, p = 0.04, p = 0.03, respectively). By multivariate analysis, lymphatic invasion and the number of tumor‐involved SLNs remained significant predictors of non‐SLN involvement. In breast cancer patients with a positive SLN, lymphatic invasion and the number of tumor‐involved SLNs were both independent predictors of non‐SLN involvement.

Utility of quantitative 99mTc-phytate scintigraphy to diagnose early-stage non-alcoholic steatohepatitis

Objective. In patients with non-alcoholic fatty liver disease (NAFLD), liver biopsy remains the only reliable method to differentiate simple steatosis from non-alcoholic steatohepatitis (NASH). The objective of this study was to evaluate the efficacy of non-invasive 99mTc-phytate scintigraphy in the diagnosis of NASH. Material and methods. Thirty-seven patients with suspected NAFLD at the time of liver biopsy also underwent 99mTc-phytate scintigraphy. Signal intensities of regions of interest (ROI) in the liver, spleen, and heart were measured. We also examined scintigraphic features in a nutritional model of NASH in rats fed a methionine- and choline-deficient (MCD) diet. Results. The liver/spleen uptake ratio determined by scintigraphy was significantly decreased in patients with NASH in comparison with patients with simple steatosis. The liver/spleen ratio was an independent predictor distinguishing NASH from simple steatosis. The decrease was observed for all stages of NASH, including the early stage (stages 1 and 0). In animal studies, the liver/spleen uptake ratio was significantly decreased in rats after 8 weeks of MCD dietary feeding in comparison with control diet-fed rats. Conclusions. The non-invasive 99mTc-phytate scintigraphy test is a reliable tool to differentiate NASH from simple steatosis.

Preoperative risk evaluation in diabetic patients without angina

AIMS The aim of the current study was to clarify whether stress myocardial perfusion single-photon emission computed tomography (SPECT) stratifies perioperative cardiac risk in noncardiac surgery of diabetic patients without chest pain. METHODS This study enrolled consecutive 284 patients with diabetes mellitus (DM) without chest pain who underwent noncardiac surgery after dipyridamole stress SPECT. Myocardial perfusion and cardiac function were simultaneously evaluated in the SPECT examination. We sought clinical and imaging variables predictive of perioperative cardiac events, and estimated the prognostic value of SPECT. RESULTS No clinical risk factors were proved to be significant predictors of perioperative cardiac events except the duration of diabetes. In contrast, myocardial perfusion imaging itself and the combination of information on perfusion and cardiac function provided significant risk stratification. The event rate in patients with normal perfusion was low regardless of surgical procedures, while that in patients with abnormal perfusion increased depending on the operation risk. CONCLUSIONS Normal myocardial SPECT findings ensure the low likelihood of perioperative cardiac events in DM patients without chest pain. Perfusion and/or functional abnormalities are associated with the adverse outcome especially in high-risk operation.

Biodistribution of immunoliposome labeled with Tc-99m in tumor xenografted mice

ObjectiveImmunoliposome (PEG, GAH, liposome; PGL), consisting of F(ab′)2 fragment of monoclonal antibody, GAH and polyethyleneglycol-coated (PEGylated) liposome was provided. Immunoliposome, PGL was labeled with technetium-99m (Tc-99m) by two methods: labeling F(ab′)2 fragment with Tc-99m; Tc-99m-PGL, and entrapping Tc-99m into liposome; PGL[Tc-99m]. The objective of this study was to compare the biodistribution of Tc-99m-PGL and PGL[Tc-99m] in human gastric cancer xenografted mice.MethodsTc-99m-PGL, PGL[Tc-99m], and Tc-99m-entrapped liposome; Lipo[Tc-99m] were prepared. They were injected into human gastric cancer, MKN45, xenografted mice via the tail vein, and their biodistribution was studied.ResultsNo marked accumulation of either PGL[Tc-99m] or Lipo[Tc-99m] was observed in the stomach. The uptake of Tc-99m-PGL by the liver, spleen, and lung was higher than that by the tumor. On the other hand, the uptake of PGL[Tc-99m] by the lung and spleen was markedly lower as compared with that of Tc-99m-PGL; the accumulation of PGL[Tc-99m] was lower in the lung and higher in the spleen as compared with that of the tumor. Although the liver uptake of PGL[Tc-99m] was markedly decreased as compared with that of Tc-99m-PGL, it was higher than the uptake of the tumor. The Tc-99m-PGL was strongly taken up by the tumor, with a high level of incorporation also seen in the stomach. These findings suggest the need for further study of the labeling stability.ConclusionsPGL[Tc-99m] appears to show promise for high tumor uptake and retention. This is an important implication for the potential application of immunoliposomes entrapped with Re-186, instead of Tc-99m, in internal radiotherapy.