Anuradha Chakraborti

Telomerase activity, telomere length and human telomerase reverse transcriptase expression in hepatocellular carcinoma is independent of hepatitis virus status

Background: Telomerase expression and the maintenance of a critical telomere length (TL) in cancer initiation indicates that telomere shortening and telomerase expression initiates cancer by induction of chromosomal instability.

Elevation of interleukin‐18 in chronic hepatitis C: implications for hepatitis C virus pathogenesis

The outcome of hepatitis C virus (HCV) infection is determined by the interplay between the virus and the host immune response. Interleukin (IL)‐18, an interferon‐γ‐inducing factor, plays a critical role in the T helper type 1 (Th1) response required for host defence against viruses, and antibodies to IL‐18 have been found to prevent liver damage in a murine model. The present study was conducted to investigate the possible role of IL‐18 in the pathogenesis and persistence of HCV. IL‐18 levels were measured in sera of 50 patients at various stages of HCV infection (resolved, chronic and cirrhosis) and compared with those of normal controls. IL‐18 gene expression was studied in peripheral blood mononuclear cells (PBMC) from each group, and in liver biopsy tissue from patients with chronic hepatitis C. The mean levels of IL‐18 in sera were markedly elevated in patients with chronic hepatitis and cirrhosis, and were reduced in patients with resolved HCV infection. The serum IL‐18 concentrations were related to the Child–Pugh severity of liver disease in cirrhotic patients. There also existed a strong positive correlation of IL‐18 levels with histological activity score and necrosis. IL‐18 mRNA expression was significantly up‐regulated in the PBMC of cirrhotic patients when compared with other groups, while in the liver, higher levels of IL‐18 transcripts were expressed in patients with chronic hepatitis C. The results of our study indicate that IL‐18 levels reflect the severity and activity of HCV infection, and may contribute to the pathogenesis and progression of liver disease associated with HCV.

Overexpression of microRNA‐122 enhances in vitro hepatic differentiation of fetal liver‐derived stem/progenitor cells

MicroRNAs (miRNAs) are a versatile class of tiny non‐coding RNAs involved in regulation of various biological processes. miRNA‐122 (miR‐122) is specifically and abundantly expressed in human liver. However, the role of miR‐122 in differentiation of fetal liver stem/progenitor cells into hepatocytes remains unclear. In this study, dual positive CD34+/CD117+ expressing human fetal liver stem/progenitor cells was enriched by magnetic cell sorting and cultured in vitro. The level of miR‐122 was found to be increased at specific time intervals. Interestingly, during the differentiation process of hepatocyte‐like cells, the increase in expression of miR‐122 was positively correlated with expression of hepatocyte‐specific genes. The status of differentiation process was improved by transfection of miR‐122 into enriched stem/progenitor cells. The expression level of hepatic‐specific genes as well as liver‐enriched transcription factors (LETFs) was significantly increased by overexpression of miR‐122 in fetal liver stem/progenitor cells. Thus, the study delineated the role of hepato‐specific miR‐122 in differentiation of fetal liver stem/progenitor cells into hepatocyte‐like cells which could be used as a therapeutic target molecule to generate abundant hepatocytes. J. Cell. Biochem. 114: 1575–1583, 2013.

Molecular heterogeneity among north Indian isolates of Group A Streptococcus

Aim:  To monitor molecular heterogeneity among the clinical isolates of group A Streptococcus (GAS) from north India by Vir and emm typing.

Small intestinal bacterial overgrowth and toll-like receptor signaling in patients with non-alcoholic fatty liver disease

The pathogenesis of non‐alcoholic fatty liver disease (NAFLD) is multifactorial. There is sparse literature on the role of small intestinal bacterial overgrowth (SIBO) and toll‐like receptor (TLR) signaling in NAFLD. The present study evaluated the relationship of SIBO with expression of TLR signaling genes in patients with NAFLD.

Comparative analysis of emm type pattern of Group A Streptococcus throat and skin isolates from India and their association with closely related SIC, a streptococcal virulence factor

BackgroundGroup A streptococcus (GAS) causes a wide variety of life threatening diseases in humans and the incidence of such infections is high in developing countries like India. Although distribution of emm types of GAS in India has been described, there is a lack of data describing either the comparative distribution of emm types in throat versus skin isolates, or the distribution of certain virulence factors amongst these isolates. Therefore in the present study we have monitored the emm type pattern of Group A streptococcus throat and skin isolates from India. Additionally, the association of these isolates with closely related sic (crs), a multifunctional compliment binding virulence factor, was also explored.ResultsOf the 94 (46 throat and 48 skin) isolates analyzed, 37 emm types were identified. The most frequently observed emm types were emm49 (8.5%) and emm112 (7.5%) followed by 6.5% each of emm1-2, emm75, emm77, and emm81. Out of 37 emm types, 27 have been previously reported and rest were isolated for the first time in the Indian Community. The predominant emm types of throat (emm49 and emm75) samples were different from those of skin (emm44, emm81 and emm112) samples. After screening all the 94 isolates, the crs gene was found in six emm1-2 (crs1-2) isolates, which was confirmed by DNA sequencing and expression analysis. Despite the polymorphic nature of crs, no intravariation was observed within crs1-2. However, insertions and deletions of highly variable sizes were noticed in comparison to CRS isolated from other emm types (emm1.0, emm57). CRS1-2 showed maximum homology with CRS57, but the genomic location of crs1-2 was found to be the same as that of sic1.0. Further, among crs positive isolates, speA was only present in skin samples thus suggesting possible role of speA in tissue tropism.ConclusionDespite the diversity in emm type pattern of throat and skin isolates, no significant association between emm type and source of isolation was observed. The finding that the crs gene is highly conserved even in two different variants of emm1-2 GAS (speA +ve and -ve) suggests a single allele of crs may be prevalent in the highly diverse throat and skin isolates of GAS in India.

Biofilm formation in clinical isolates of group B streptococci from north India.

Many bacterial species are capable of living as biofilm, thought to be the predominant growth mode for bacteria in natural environments. Increasing evidence implicates biofilm as the cause of various human infections. In this study, biofilm formation was demonstrated in group B streptococci (GBS) isolated from different sources in the north Indian community at various pH ranges as well as sugar concentrations and correlated it with different serotypes and surface gene (c alpha) profiles. The capability to form biofilm was better demonstrated in strains from asymptomatic carriers (pregnant women) compared to symptomatic patients. Quantitatively bacterial adherence with host cells was greater in isolates that produced biofilm under neutral conditions. This study assessed the biofilm formation in clinical isolates of GBS, which is a step towards understanding its role in pathogenesis.

Characterization of Giardia lamblia groups A and B from North India by isoenzyme and random amplified polymorphic DNA analysis

Giardia lamblia ( syn. G. intestinalis) infection in young adults leads to acute/chronic diarrhea in some individuals and is asymptomatic in others. Recently, G. lamblia strains have been characterized as group A (symptomatic) and group B (asymptomatic or control) by advanced isoenzyme and molecular biology studies. In the present brief pilot study, ten G. lamblia isolates obtained from five symptomatic (group A) and five asymptomatic (group B) persons were characterized by isoenzyme and random amplified polymorphic DNA (RAPD) analysis. Isoenzyme analysis demonstrated remarkable homogeneity in seven enzyme patterns, the exception, being that of phosphoglucomutase, for which two zymodemes (I and III) were observed. In contrast, RAPD analysis showed homogeneity for eight primers; exceptions were two primers, A02 and B05, which separated group A G. lamblia isolates into two rapdemes (AR1 and AR2) and group B G. lamblia isolates into four rapdemes (BR1, BR2, BR3 and BR4). Further phenetic analysis showed average genetic distances of 0.105 within group A and 0.121 within group B G. lamblia isolates according to Jaccords distance scale, which suggests that both lineages appear to consist of a range of variants with no significant (P < 0.05) genetic diversity. The two techniques demonstrated a positive association with regard to differentiation between group A and group B G. lamblia isolates. These very preliminary results indicate that RAPD analysis could be a potentially useful substitute for isoenzyme analysis.

Molecular detection and sequence analysis of hepatitis E virus in patients with viral hepatitis from North India.

Viral hepatitis is a major cause of mortality and morbidity in developing countries. Hepatitis E virus (HEV) is responsible for both sporadic and epidemic outbreaks of viral hepatitis in India. Here a total of 843 samples were collected: 685 from patients with acute viral hepatitis (AVH), 70 from patients with fulminant hepatic failure (FHF), 53 from patients with chronic liver disease (CLD), 11 from patients with antituberculosis therapy (ATT)-induced jaundice, and 24 from pregnant women. When tested for anti-HEV IgM, 58.3% of the pregnant women, 41.4% of the patients with FHF, 38.6% of the patients with AVH, 9.4% of the patients with CLD, and 18.2% of the patients with ATT-induced jaundice tested positive. We found that 34% and 16% of the acute hepatitis patients and fulminant hepatitis patients, respectively, showed no reactivity to the existing viral hepatitis markers and were thus grouped as non A to E. Among the HEV IgM-positive cases, males outnumbered females (62.8% versus 37.1%). HEV RNA was found in 35% of fulminant and 9.4% of acute hepatitis patients. From phylogenetic analysis, we observed that all the isolates were clustered within genotype 1. Critical analysis placed the acute isolates along with strains under subtype Ia, while the fulminant isolates clustered along with the FHF strain (X98292) under subtype Ic. The segregation of HEV isolates from AVH and FHF patients into different subtypes raises interesting questions on the molecular basis of HEV disease severity.

Subtype distribution of Haemophilus influenzae isolates from north India.

A total of 120 Haemophilus influenzae isolates from blood, cerebrospinal fluid, sputum and throat swabs of patients and carriers in North India was characterised by biotyping, ribotyping and random amplification of polymorphic DNA (RAPD)-PCR. Of these, 77 isolates (64%) were serotype b; the other 43 (36%) were non-typable. Biotype I was the most predominant among the typable strains and biotype II among the non-typable strains. Ribotyping with restriction endonucleases HaeIII and EcoRI differentiated the isolates into three and six ribotypes, respectively. However, RAPD fingerprints generated by the application of arbitrary primers AP1 and AP2 provided a higher level of discrimination. RAPD typing revealed distinct polymorphism among the serologically typable isolates. This study is the first report that stratifies the subtypes of H. influenzae strains from India by molecular techniques.