Decreased phagocytic activity of Kupffer cells in a rat nonalcoholic steatohepatitis model

AIM: To investigate Kupffer cell dynamics and phagocytic activity,using a rat nonalcoholic steatohepatitis (NASH) model. METHODS: Male F344 rats were fed either a control diet or a choline-deficient L-amino acid-defined (CDAA) diet,followed by contrast enhanced ultrasonography (CEUS) using Levovist. The uptake of latex beads by the Kupffer cells was determined by fluorescent microscopy. The status of the Kupffer cells was compared between the two groups,using the immunohistochemical staining technique. RESULTS: After 4 or more wk of the CDAA diet,CEUS examination revealed a decrease in the signal intensity,20 min after intravenous Levovist. Fluorescent microscopic examination showed that the uptake of latex beads by the Kupffer cells was reduced at week 1 and 2 in the study group,compared with the controls,with no further reduction after 3 wk. Immunohistochemical staining revealed no significant difference in the Kupffer cell counts between the control group and the CDAA group. CONCLUSION: CEUS examination using Levovist demonstrated reduced contrast effect and phagocytic activity in the liver parenchymal phase,although the Kupffer cell numbers were unchanged,indicating reduced phagocytic function of the Kupffer cells in the rat NASH model. We believe that CEUS examination using Levovist is a useful screening modality,which can detect NASH in fatty liver patients.

Innate immune reactivity of the liver in rats fed a choline-deficient L-amino-acid-defined diet

AIM： To investigate the innate immune reactivity of tumor necrosis factor-alpha （TNF-α）, Toll-like receptor 4 （TLR4）, and CD14 in the liver of non-alcoholic steatohepatitis （NASH） model rats. METHODS： Male F344 rats were fed a cholinedeficient L-amino-acid-defined （CDAA） diet. The rats were killed after 4 or 8 wk of the diet, and their livers were removed for immunohistochemical investigation and RNA extraction. The liver specimens were immunostained for TNF-α, TLR4, and CD14. The gene expressions of TNF-α, TLR4, and CD14 were determined by reverse-transcriptase polymerase chain reaction （RT-PCR）. Kupffer cells were isolated from the liver by Percoll gradient centrifugation, and were then cultured to measure TNF-α production. RESULTS： The serum and liver levels of TNF-~ in the CDAA-fed rats increased significantly as compared with the control group, as did the immunohistochemical values and gene expressions of TNF-α, TLR4, and CD14 with the progression of steatohepatitis. TNF-α production from the isolated Kupffer cells of the CDAAfed rats was elevated by lipopolysaccharide stimulation. CONCLUSION： The expressions of TNF-α, TLR4, and CD14 increased in the NASH model, suggesting that

Immunotherapy for nonalcoholic steatohepatitis using the multiple cytokine production modulator Y-40138

AIM:To investigate the possible use of the multiple cytokine production modulator,Y-40138,as a novel immunotherapy in the rat nonalcoholic steatohepatitis (NASH) model. METHODS:We allocated 6-wk-old male F344 rats to choline-supplemented,L-amino acid-defined (CSAA) diet (control group),CSAA diet + Y-40138 (control + Y-40138 group),choline-def icient,L-amino acid-def ined (CDAA) diet (NASH group),or CDAA diet + Y-40138 (NASH + Y-40138 group). In each group,we measured the plasma alanine aminotransferase (ALT) levels,and the plasma and liver levels of tumor necrosis factor-α (TNF-α),interferon-γ (IFN-γ),and interleukin-10 (IL-10). Tissue specimens of phosphate buffered saline-perfused liver were subjected to hematoxylin and eosin staining,Azan staining,Sirius red staining,and immunohistochemical staining (for Kupffer cells and TNF-α). We then extracted Kupffer cells from the collagenase-perfused livers using the Percoll gradient centrifugation method,and measured the TNF-α levels in the supernatant (in vitro TNF-α production by Kupffer cells) using an enzyme-linked immunosorbent assay kit.RESULTS:In comparison to the NASH group,serumALT elevation was mild,production of serum and liver TNF-α and IFN-γ was inhibited,and IL-10 production was increased in the NASH + Y-40138 group. Amelioration of liver histology was also noted in the NASH + Y-40138 group. Kupffer cell immunohistochemical staining revealed no differences between groups,whereas TNF-α immunohistochemical staining showed fewer stained cells in the NASH + Y-40138 group than in the NASH group. The TNF-α levels in the in-vitro Kupffer cell culture supernatant were lower in the NASH + Y-40138 group than in the NASH group.CONCLUSION:Administration of Y-40138 to NASH model rats reduced hepatic inflammation and suppressed fibrosis. These results indicate that the multiple cytokine production modulator,Y-40138,is promising as a novel treatment for NASH.

A Method for Determining <i>Batillaria attramentaria</i>Distribution Using Aerial Balloon Photography and a Vegetation Index Camera: Demonstration at the Yatsu Tidal Flat, Chiba Prefecture

Located in Chiba Prefecture, the Yatsu Tidal Flat is an important stopover for birds migrating between cold regions such as Siberia and warm regions such as Southeast Asia and Australia. Its importance led to its selection in 1993 as the first tidal flat in Japan to be registered under the Convention on Wetlands of International Importance especially as Waterfowl Habitat (the Ramsar Convention). However, the Yatsu Tidal Flat has in more recent years witnessed blooms of Ulva spp. (sea lettuce) and an increase in exotic species such as Batillaria attramentaria (Japanese mud snail) and Mercenaria mercenaria (hard clam), fueling concerns that the increasing spatial domination of the tidal flat by such species and competition with other species for food may drive a decline in the habitat’s self-cleaning capabilities. For this study, we focused on Batillaria attramentaria, which is now so widely distributed in the Yatsu Tidal Flat as to preclude reliable monitoring via aerial photographs or satellite imagery. Accordingly, we tested the utility of a simplified method for obtaining data on the distribution of Batillaria attramentaria by using aerial balloon photography and a vegetation index camera capable of generating NDVI data. Our results show that under certain conditions, this method can indeed be used to determine Batillaria attramentaria distribution.