Diet high in fructose leads to an overexpression of lipocalin-2 in rat fatty liver

AIM:To explore lipocalin-2(LCN-2)expression and its possible role and mechanism(s)of production in rat models of diet-inducible fatty liver.METHODS:Fatty liver was triggered in male SpragueDawley rats fed either with liquid Lieber-DeCarli(LDC)or LDC+70%cal fructose(L-HFr)diet for 4 or 8 wk.Chow-nourished animals served as controls.Hepatic expression of LCN-2 and other metabolic and inflammatory mediators was assessed by quantitative reverse transcription polymerase chain reaction and Western blotting.Serum LCN-2,fasting leptin,and lipid profile were evaluated via Enzyme-Linked Immunosorbent Assay,Radioimmunoassay,and colorimetric assays,respectively.The localization of LCN-2 in the liver was detected by using immunofluorescence staining.Furthermore,HE stain was used to evaluate hepatic fatdegeneration and inflammation.RESULTS:Both LDC-fed and L-HFr-fed rat histologically featured fatty liver.In the liver,mRNA transcriptions of Mcp-1,a2-m,Il-8 and Glut5 were increased in the L-HFr group at both time points(P<0.001),while the transcription of Tlr4,Inos,and Tnf-a was significantly up-regulated at week 4.Interestingly,hepatic Lcn-2 expression was 90-fold at week 4 and 507-fold at week 8 higher in L-HFr-subjected rats vs control(P<0.001).In contrast to HDL-cholesterol,systemic levels of LCN-2,fasting leptin and triglycerides were elevated in the L-HFr regimen(P<0.001).Moreover,protein expression of hepatic LCN-2,CD14,phosphoMAPK,caspase-9,cytochrome c and 4-hydroxynonenal was increased in the L-HFr group.Conversely,the hepatic expression of PGC-1a(a mitochondrial-biogenic protein)was reduced in the L-HFr category at week 8.The localization of LCN-2 in the liver was predominantly restricted to MPO+granulocytes.CONCLUSION:Fructose diet up-regulates hepatic LCN-2 expression,which correlates with the increased indicators of oxidative stress and mitochondrial dysfunction.The LCN-2 may be involved in liver protection.

Lack of correlation between Treg quantification assays in inflammatory bowel disease patients

AIM:To compare the number of regulatory T-cells( Tregs) measured by flow cytometry with those obtained using a real-time quantitative PCR(q PCR) method in patients suffering from inflammatory bowel disease(IBD).METHODS:Tregs percentages obtained by both flow cytometry and q PCR methods in 35 adult IBD patients,18 out of them with Crohn′s disease(CD)and 17 with ulcerative colitis(UC)were compared to each other as well as to scores on two IBD activity questionnaires using the Harvey Bradshaw Index(HBI)for CD patients and the Simple Colitis Clinical Activity Index(SCCAI)for UC patients.The Treg percentages by flow cytometry were defined as CD4+CD25highCD127lowFOXP3+cells in peripheral blood mononuclear cells,whereas the Treg percentages by q PCR method were determined as FOXP3 promoter demethylation in genomic DNA.RESULTS:We found an average of 1.56%±0.78%Tregs by using flow cytometry,compared to 1.07%±0.53%Tregs by using q PCR in adult IBD patients.There were no significant correlations between either the percentages of Tregs measured by flow cytometry or q PCR and the HBI or SCCAI questionnaire scores in CD or UC patients,respectively.In addition,there was no correlation between Treg percentages measured by q PCR and those measured by flow cytometry(r=-0.06,P=0.73;Spearman Rho).These data suggest that,either Treg-related immune function or the clinical scores in these IBD patients did not accurately reflect actual disease activity.Until the cause(s)for these differences are more clearly defined,the resultssuggest caution in interpreting studies of Tregs in various inflammatory disorders.CONCLUSION:The two methods did not produce equivalent measures of the percentage of total Tregs in the IBD patients studied which is consistent with the conclusion that Tregs subtypes are not equally detected by these two assays.