[Effect of adipose tissue-derived mesenchymal stem cell transplantation in treatment of liver fibrosis and possible mechanism].

Objective: To investigate the effect of adipose tissue-derived mesenchymal stem cell (ADSC) transplantation in the treatment of liver fibrosis rats and possible mechanism. Methods: Subcutaneous adipose tissue in the inguinal region of rats was collected to isolate ADSCs. The rats with liver fibrosis induced by intraperitoneally injected carbon tetrachloride were divided into cell transplantation group and phosphate buffer saline (PBS) injection group, and the rats which were fed normally were enrolled as negative control group. The rats in the cell transplantation group were given tail vein injection of ADSCs, and those in the PBS injection group were given injection of 0.5 ml PBS. At 7 days after transplantation, blood samples were collected from the inferior vena cava to evaluate liver function; liver tissue was collected to measure the protein expression of hepatocyte growth factor (HGF) and alpha-smooth muscle actin (α-SMA); Masson trichrome staining was used to evaluate intrahepatic collagen deposition. Hepatic stellate cells (HSCs) were collected from the rats with liver fibrosis, and indirect co-culture of HSCs and ADSCs was performed in vitro to analyze the influence of ADSCs on the proliferation and apoptosis of HSCs. The independent samples t-test was used for comparison between groups, and an analysis of variance was used for comparison of means between multiple samples. Results: ADSCs were found in liver tissue in the transplantation group, and compared with the PBS injection group, the transplantation group had significant alleviation in hepatocyte necrosis, vacuolization, and area of fibrosis and significant reductions in the serum levels of aminotransferases, while there was no significant difference in the level of albumin between the two groups. Compared with the PBS injection group, the transplantation group had significant upregulation in the protein expression of HGF and significant downregulation in the protein expression of α-SMA (both P < 0.05). In vitro co-culture for 72 hours showed that ADSCs inhibited the proliferation of HSCs, and there was a significant difference between the co-culture group and the control group with HSCs cultured alone. Caspase-3 immunostaining showed that after co-culture for 72 hours, there was a significant difference in the apoptosis rate of HSCs between the co-culture group and the control group with HSCs cultured alone (23.42% ± 3.02% vs 14.82% ± 3.93%). Conclusion: ADSC transplantation can upregulate the expression of HGF in the liver, promote the apoptosis of HSCs, and thus alleviate liver fibrosis.

Rescue of the colony-stimulating factor 1 (CSF-1)-nullizygous mouse (Csf1(op)/Csf1(op)) phenotype with a CSF-1 transgene and identification of sites of local CSF-1 synthesis.

Colony-stimulating factor 1 (CSF-1) regulates the survival, proliferation, and differentiation of mononuclear phagocytes. It is expressed as a secreted glycoprotein or proteoglycan found in the circulation or as a biologically active cell-surface glycoprotein. To investigate tissue CSF-1 regulation, CSF-1-null Csf1(op)/Csf1(op) mice expressing transgenes encoding the full-length membrane-spanning CSF-1 precursor driven by 3.13 kilobases of the mouse CSF-1 promoter and first intron were characterized. Transgene expression corrected the gross osteopetrotic, neurologic, weight, tooth, and reproductive defects of Csf1(op)/Csf1(op) mice. Detailed analysis of one transgenic line revealed that circulating CSF-1, tissue macrophage numbers, hematopoietic tissue cellularity, and hematopoietic parameters were normalized. Tissue CSF-1 levels were normal except for elevations in 4 secretory tissues. Skin fibroblasts from the transgenic mice secreted normal amounts of CSF-1 but also expressed some cell-surface CSF-1. Also, lacZ driven by the same promoter/first intron revealed beta-galactosidase expression in hematopoietic, reproductive, and other tissue locations proximal to CSF-1 cellular targets, consistent with local regulation by CSF-1 at these sites. These studies indicate that the 3.13-kilobase promoter/first intron confers essentially normal CSF-1 expression. They also pinpoint new cellular sites of CSF-1 expression, including ovarian granulosa cells, mammary ductal epithelium, testicular Leydig cells, serous acinar cells of salivary gland, Paneth cells of the small intestine, as well as local sites in several other tissues.

Natural isolates of simian virus 40 from immunocompromised monkeys display extensive genetic heterogeneity: new implications for polyomavirus disease.

Simian virus 40 (SV40) DNAs in brain tissue and peripheral blood mononuclear cells (PBMCs) of eight simian immunodeficiency virus-infected rhesus monkeys with SV40 brain disease were analyzed. We report the detection, cloning, and identification of five new SV40 strains following a quadruple testing-verification strategy. SV40 genomes with archetypal regulatory regions (containing a duplication within the G/C-rich regulatory region segment and a single 72-bp enhancer element) were recovered from seven animal brains, two tissues of which also contained viral genomes with nonarchetypal regulatory regions (containing a duplication within the G/C-rich regulatory region segment as well as a variable duplication within the enhancer region). In contrast, PBMC DNAs from five of six animals had viral genomes with both regulatory region types. It appeared, based on T-antigen variable-region sequences, that nonarchetypal virus variants arose de novo within each animal. The eighth animal exclusively yielded a new type of SV40 strain (SV40-K661), containing a protoarchetypal regulatory region (lacking a duplication within the G/C-rich segment of the regulatory region and containing one 72-bp element in the enhancer region), from both brain tissue and PBMCs. The presence of SV40 in PBMCs suggests that hematogenous spread of viral infection may occur. An archetypal version of a virus similar to SV40 reference strain 776 (a kidney isolate) was recovered from one brain, substantiating the idea that SV40 is neurotropic as well as kidney-tropic. Indirect evidence suggests that maternal-infant transmission of SV40 may have occurred in one animal. These findings provide new insights for human polyomavirus disease.

Outbreaks of gastroenteritis in elderly nursing homes and retirement facilities associated with human caliciviruses.

Eleven outbreaks of acute gastroenteritis, eight of which were in nursing homes or retirement facilities, were reported in virginia during the winter of 1993-1994. Serum samples (four outbreaks) and stool samples (two outbreaks) from involved people were tested for human calicivirus (HuCV) infection by enzyme immune assays (EIAs) using recombinant Norwalk virus (rNV) and Mexico virus (rMX) capsid antigens and reverse transcription-polymerase chain reaction (RT-PCR). Of the 31 pairs of acute and convalescent serum specimens tested, 24 had a fourfold or more titer increase to rMX and 4 responded to rNV. In all four outbreaks, the geometric mean titers (GMTs) against rMX were significantly higher than those against rNV in the convalescent, but not in the acute phase of illness. The antibody response to rMX among these patients was also higher than to rNV (summary mean 32-fold increase vs. 0.7-fold increase, respectively, P < .001). Antigen was detected in 5 of 21 stool specimens tested by the rMX EIA, RNA in 12 of 17 stool specimens tested by RT-PCR, and small round structured virus (SRSV) particles in 12 of 21 by electron microscopy (EM); none were positive by the rNV EIA. Sequence analysis of the RT-PCR-amplified products from the viral RNA polymerase region revealed 92-93% amino acid identity with Snow Mountain agent (SMA), 86% with MX, 58-59% with NV, and 31-32% with Sapporo HuCV, suggesting that these viruses belong to the SMA HuCV genogroup.