Transplantation of immortalized human fetal hepatocytes prevents acute liver failure in 90% hepatectomized mice

AIM

The aim of this study was to investigate whether human fetal hepatocytes are amenable to simian virus 40 large T-antigen (SV40Tag) mediated immortalization and whether the immortalized cells rescue mice with acute liver failure induced by 90% hepatectomy.

METHODS

We constructed a retroviral vector expressing a thermolabile mutant SV40Tag for transfer into primary human fetal hepatocytes. We quantitatively detected the synthetic ability for albumin and urea by the immortalized cells, which were subcutaneously inoculated into mice with severe combined immunodeficiency (SCID) to evaluate tumorigenzcity. The immortalized cells were also transplanted into the spleens of mice with acute liver failure.

RESULTS

One clone resulting after selection, referred to as HepCL, was highly differentiated, growing steadily in a chemically defined serum-free medium. HepCL cells were positive for albumin, cytokeratin 18, and cytokeratin 19 immunocytochemical staining. The average synthetic efficacies of HepCL cells for albumin and urea were comparable to that of unmodified primary human fetal hepatocytes. The population doubling time of HepCL cells in the logarithmic growth phase was approximately 17 hours. HepCL cells showed no oncogenicity in immunodeficient mice at 16 months. Mice receiving HepCL cells (G1) and primary human fetal hepatocytes (G2) showed significantly lower blood ammonia levels after 90% hepatectomy. Pairwise comparisons between the 4 groups showed that xenotransplantation of HepCL (G1) or primary fetal hepatocytes (G2) significantly improved survivals of recipient mice.

CONCLUSIONS

HepCL may be useful as a source of hepatic function for cell-based therapeutics in acute liver failure.

Intranasal brain-derived neurotrophic factor protects brain from ischemic insult via modulating local inflammation in rats

Inflammation plays a vital role in the pathogenesis of ischemic stroke. Brain-derived neurotrophic factor (BDNF) may protect brain tissues from ischemic injury. In this study, we investigated whether intranasal BDNF exerted neuroprotection against ischemic insult by modulating the local inflammation in rats with ischemic stroke. Rats were subjected to temporary occlusion of the right middle cerebral artery (120 min) and intranasal BDNF or vehicle was adminstrated 2 h after reperfusion. Infarct volume and neuron injury were measured using triphenyltetrazolium chloride, Nissl staining and TUNEL assay, respectively. Microglia were detected by immunohistofluorescence. Tumor necrosis factor-α, interleukin10 and mRNAs were evaluated by enzyme-linked immunosorbent assay and real-time quantitative polymerase chain reaction. DNA-binding activity of nuclear factor-kappa B was measured by electrophoretic mobility shift assay. BDNF level in brain tissues was markedly raised following intranasal administration. There were more Nissl positive and less TUNEL positive neurons in BDNF group than in control group while intranasal BDNF did not reduce the infarct volume significantly (n=6, 0.27±0.04 vs. 0.24±0.05, P>0.05). BDNF increased the number of activated microglia (OX-42 positive) and phagocytotic microglia (ED1 positive). BDNF suppressed tumor necrosis factor-α and mRNA expression while increasing the interleukin10 and mRNA expression. BDNF also increased DNA-binding activity of nuclear factor-kappa B (n=6, 49.78±1.23 vs. 52.89±1.64, P<0.05). Our data suggest intranasal BDNF might protect the brain against ischemic insult by modulating local inflammation via regulation of the levels of cellular, cytokine and transcription factor in the experimental stroke.

Identification of the bacterial biodiversity in koumiss by denaturing gradient gel electrophoresis and species-specific polymerase chain reaction

Bacterial biodiversity in traditional koumiss fermented milk was studied by denaturing gradient gel electrophoresis (DGGE). Target DNA bands were identified according to the reference species ladder, constructed in this study. Comigrating bands present in the DGGE profiles were resolved by species-specific PCR. The results revealed a novel bacterial profile and extensive bacterial biodiversity in koumiss. The dominant lactic acid bacteria included Lactobacillus acidophilus, Lactobacillus helveticus, Lactobacillus fermentum, and Lactobacillus kefiranofaciens. Frequently encountered bacterial species were Enterococcus faecalis, Lactococcus lactis, Lactobacillus paracasei, Lactobacillus kitasatonis, and Lactobacillus kefiri. Leuconostoc mesenteroides, Streptococcus thermophilus, Lactobacillus buchneri, and Lactobacillus jensenii were occasionally found in this product. In addition, L. buchneri, L. jensenii, and L. kitasatonis, which were never previously isolated by culture-dependent methods, were identified for the first time in the Xinjiang koumiss. Furthermore, conventional cultivation was performed by plating samples on M17, de Man-Rogosa-Sharpe, Halligan-Pearce, and Kenner fecal media. The results revealed that lactobacilli were the dominant species in the koumiss ecosystem, which was consistent with the results obtained by the DGGE analysis. This is the first systematic study of the microbial composition in koumiss, and our findings will be helpful in selecting appropriate strains for the manufacture of this product at the industrial level.

Discovery of SNP in exon 14 of the <i>ADD1</i> gene and its association with fatness traits in four meat-type duck populations (Brief Report)

Abstract. Fatness traits are important economically traits in meat producing animals including duck (WU et al. 2008a, b). In human, the α-Adducin (ADD1) gene polymorphism was associated with blood pressure and other subsequent negative effects related to obesity, cardiovascular and renal failure. In fact, there was some relationship between obesity and hypertension. Thus the ADD1 gene is a candidate gene for fatness traits and the study aims to invest the relationship between the polymorphism of the ADD1 gene and fatness and growth traits.

Coherent magnetization precession in ferromagnetic (Ga,Mn)As induced by picosecond acoustic pulses

We show that the magnetization of a thin ferromagnetic (Ga,Mn)As layer can be modulated by picosecond acoustic pulses. In this approach a picosecond strain pulse injected into the structure induces a tilt of the magnetization vector M, followed by the precession of M around its equilibrium orientation. This effect can be understood in terms of changes in magnetocrystalline anisotropy induced by the pulse. A model where only one anisotropy constant is affected by the strain pulse provides a good description of the observed time-dependent response.

Seasonal changes in antifreeze protein gene transcription and water content of beetle Microdera punctipennis (Coleoptera, Tenebrionidae) from Gurbantonggut desert in Central Asia

Desert beetle Microdera punctipennis (Coleoptera: Tenebriondae) is a special species in Gurbantonggut Desert in Central Asia. To investigate the possible strategy it employs for cold survival, seasonal changes in supercooling point (SCP), body water content, haemolymph osmolality and antifreeze protein gene (Mpafp) expression were measured over 13 months. Our results show SCPs in M. punctipennis adults changed from -8.0°C in summer to -18.7°C in winter. During winter, adults endured modest water loss; total water decreased from 65.4 percent in summer to 55.9% in winter. Mpafp mRNAs level increased by 13.1 fold from summer to early winter, and haemolymph osmolality increased accordingly from 550 mOsm to 1486 mOsm. Correlation coefficient of Mpafp mRNAs level and SCP indicates that Mpafp mRNA explained 65.3 percent of the variation in SCPs. The correlation between Mpafp mRNA level and total water reflected an indirect influence of antifreeze protein on water content via reducing SCP.

Effect of waterborne copper exposure on growth, hepatic enzymatic activities and histology in Synechogobius hasta

The present study was conducted to determine growth, hepatic enzymatic activities and histology in Synechogobius hasta exposed to waterborne copper concentrations of 0 (control), 0.15 and 0.3 mg Cu/l, respectively, for 15 days, and explore whether waterborne copper exposure could induce the fatty liver syndrome for the fish species. Growth (WG and SGR) declined, but HSI increased in S. hasta with increasing waterborne copper levels (P<0.05). Waterborne copper exposure also significantly increased lipid content and reduced protein content in both whole body and liver, and increased copper accumulation in whole body and vertebrae. Copper exposure changed hepatic enzymatic activities (SOD, CAT, SDH, PK, LDH, LPL and HL) and increased hepatic lipid peroxidation level, impaired the histological structure of the gill and liver in S. hasta. Thus, our study demonstrated for the first time that waterborne Cu exposure could induce fatty liver syndrome in fish.

Multivalent immunity targeting tumor-associated antigens by intra-lymph node DNA-prime, peptide-boost vaccination

Active immunotherapy of cancer has yet to yield effective therapies in the clinic. To evaluate the translatability of DNA-based vaccines we analyzed the profile of T-cell immunity by plasmid vaccination in a murine model, using transcriptome microarray analysis and flow cytometry. DNA vaccination resulted in specific T cells expressing low levels of co-inhibitory molecules (most notably PD-1), strikingly different from the expression profile elicited by peptide immunization. In addition, the T-cell response primed through this dual-antigen-expressing plasmid (MART-1/Melan-A and tyrosinase) translated into a substantial proliferation capacity and functional conversion to antitumor effector cells after tyrosinase and MART-1/Melan-A peptide analog boost. Furthermore, peptide boost rescued the immune response against the subdominant tyrosinase epitope. This immunization approach could be adapted to elicit potent immunity against multiple tumor antigens, resulting in a broader immune response that was more effective in targeting human tumor cells. Finally, this study sheds light on a novel mechanism of immune homeostasis through synchronous regulation of co-inhibitory molecules on T cells, highly relevant to heterologous prime boost approaches involving DNA vaccines as priming agents.