Sukanta Ray

Fetuin-A, a hepatic secretory protein, has recently been implicated in insulin resistance and Type 2 diabetes. It is an endogenous inhibitor of insulin receptor tyrosine kinase. However, regulation of fetuin-A synthesis in relation to insulin resistance is unclear. In the present paper, we report that both non-esterified ('free') fatty acids and fetuin-A coexist at high levels in the serum of db/db mice, indicating an association between them. For an in-depth study, we incubated palmitate with HepG2 cells and rat primary hepatocytes, and found enhanced fetuin-A secretion to more than 4-fold over the control. Interestingly, cell lysates from these incubations showed overexpression and activity of NF-kappaB (nuclear factor kappaB). In NF-kappaB-knockout HepG2 cells, palmitate failed to increase fetuin-A secretion, whereas forced expression of NF-kappaB released fetuin-A massively in the absence of palmitate. Moreover, palmitate stimulated NF-kappaB binding to the fetuin-A promoter resulting in increased reporter activity. These results suggest NF-kappaB to be the mediator of the palmitate effect. Palmitate-induced robust expression of fetuin-A indicates the occurrence of additional targets, and we found that fetuin-A severely impaired adipocyte function leading to insulin resistance. Our results reveal a new dimension of lipid-induced insulin resistance and open another contemporary target for therapeutic intervention in Type 2 diabetes.

BACKGROUND: Isolated hepatobiliary or pancreatic tuberculosis (TB) is rare and preoperative diagnosis is difficult. We reviewed our experience over a period two decades with this rare site of abdominal tuberculosis. METHODS: The records of 18 patients with proven histological diagnosis of hepatobiliary and pancreatic tuberculosis were reviewed retrospectively. The demographic features, sign and symptoms, imaging, cytology/histopathology, procedures performed, outcome and follow up data were obtained from the departmental records. The diagnosis of tuberculosis was based on granuloma with caseation necrosis on histopathology or presence of acid fast bacilli. RESULTS: Of 18 patients (11 men), 11 had hepatobiliary TB while 7 had pancreatic TB. Two-thirds of the patients were < 40 years (mean: 42 yrs; range 19-70 yrs). The duration of the symptoms varied between 2 weeks to 104 weeks (mean: 20 weeks). The most common symptom was pain in the abdomen (n = 13), followed by jaundice (n = 10), fever, anorexia and weight loss (n = 9). Five patients (28%) had associated extra-abdominal TB which helped in preoperative diagnosis in 3 patients. Imaging demonstrated extrahepatic bile duct obstruction in the patients with jaundice and in addition picked up liver, gallbladder and pancreatic masses with or without lymphadenopathy (peripancreatic/periportal). Preoperative diagnosis was made in 4 patients and the other 14 were diagnosed after surgery. Two patients developed significant postoperative complications (pancreaticojejunostomy leak 1 intraabdominal abscess 1) and 3 developed ATT induced hepatotoxicity. No patient died. The median follow up period was 12 months (9-96 months). CONCLUSION: Tuberculosis should be considered as a differential diagnosis, particularly in young patients, with atypical signs and symptoms coming from areas where tuberculosis is endemic and preoperative tissue and/or cytological diagnosis should be attempted before labeling them as hepatobiliary and pancreatic malignancy.

Macrophage infiltration into adipose tissue during obesity and their phenotypic conversion from anti-inflammatory M2 to proinflammatory M1 subtype significantly contributes to develop a link between inflammation and insulin resistance; signaling molecule(s) for these events, however, remains poorly understood. We demonstrate here that excess lipid in the adipose tissue environment may trigger one such signal. Adipose tissue from obese diabetic db/db mice, high fat diet-fed mice, and obese diabetic patients showed significantly elevated fetuin-A (FetA) levels in respect to their controls; partially hepatectomized high fat diet mice did not show noticeable alteration, indicating adipose tissue to be the source of this alteration. In adipocytes, fatty acid induces FetA gene and protein expressions, resulting in its copious release. We found that FetA could act as a chemoattractant for macrophages. To simulate lipid-induced inflammatory conditions when proinflammatory adipose tissue and macrophages create a niche of an altered microenvironment, we set up a transculture system of macrophages and adipocytes; the addition of fatty acid to adipocytes released FetA into the medium, which polarized M2 macrophages to M1. This was further confirmed by direct FetA addition to macrophages. Taken together, lipid-induced FetA from adipocytes is an efficient chemokine for macrophage migration and polarization. These findings open a new dimension for understanding obesity-induced inflammation.

Abstract Diagnosis of hepatocellular carcinoma (HCC) remains challenging to clinicians, particularly in a patient with low alpha‐fetoprotein. Here, in silico, ex vivo and in vitro data were combined to identify liver‐specific exosomal miRNAs as an early diagnostic marker for HCC. Transcriptome profiling for mRNA and small RNA in same HCV‐HCC and normal liver tissues followed by cross‐validation of 41 deregulated miRNAs (log 2 FoldChange &gt; 1.5, P adj &lt; .1) with GEO/TCGA datasets of HCV/HBV related HCC vs normal/adjacent tissue revealed three miRNAs were commonly deregulated (miR‐10b/miR‐21/miR‐182) among all HCC irrespective of viral etiology. Targets of top deregulated miRNAs were identified by TargetScan/miRwalk and validated in mRNA transcriptome data followed by Panther/Gene Ontology enrichment/Cytoscape analysis suggested that targets were mostly from carcinogenesis pathways. Hence, those miRNAs were validated in normal and HCV‐HCC tissues by qRT‐PCR and subsequently in plasma‐derived‐exosomes of both HBV/HCV infected non‐HCC (chronic hepatitis [CH]/liver cirrhosis [LC]) and HCC samples, and in liver‐specific Anti‐Asgr2 immuno‐enriched exosomes. Exosomes were verified using Nanosight/TEM/immune‐blotting with anti‐Alix/anti‐GRP78/anti‐Asgr2. Along with miR‐21‐5p, miR‐10b‐5p/miR‐221‐3p/miR‐223‐3p was found significantly upregulated in the exosome of HCC patients than CH/non‐HCC. The comparable expression pattern was seen in anti‐Asgr2 immuno‐precipitated exosomes. Interestingly, the AFP level was found below 250 ng/mL in about 94% of HCV‐HCC and 62% of HBV‐HCC patients. ROC analysis showed that miR‐10b‐5p + miR‐221‐3p + miR‐223‐3p + miR‐21‐5p could differentiate CH/non‐HCC(CH + LC) from HCC with AUROC: 0.86 (97.5% CI: 0.77‐0.94)/0.80 (97.5% CI: 0.70‐0.89), sensitivity: 74%/58% and specificity: 86%/95% while miR‐10b‐5p + miR‐221‐3p + miR‐223‐3p showed AUROC: 0.84 (97.5% CI: 0.74‐0.94)/0.74 (97.5% CI: 0.63‐0.84), sensitivity: 86%/86% and specificity:66%/53% for low AFP‐HCC vs CH/non‐HCC, respectively, having better sensitivity than the combination of four miRNAs. Multivariate analysis further revealed low Albumin and high miR‐21‐5p as probable independent risk factor for HCC.