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ABSTRACT: Dendritic cells (DCs) can initiate the expansion of regulatory T cells (Tregs), which play an indispensable role in inducing transplantation tolerance. Some studies have investigated the effect of the immunosuppressant rapamycin (Rapa) on Tregs in vitro. However, the in vivo effect of Rapa combined with immature DCs (iDCs) on Tregs is unknown. This study was undertaken to determine whether allogenic iDCs combined with a short course of Rapa have the ability to selectively expand the CD4+CD25+Foxp3+ Tregs in a rat model.
Brown Norway rats were injected intravenously with 2X10(6) Lewis iDCs followed by 1 mg/kg per day Rapa intraperitoneally for 7 consecutive days. On day 8, the levels of CD4+CD25+Foxp3+ Treg cells in peripheral blood and spleen cells were analyzed by flow cytometry. IL-2, IL-4, TGF-beta1, and IFN-gamma levels in serum were assessed by ELISA. The experimental animals were divided into four groups: control, Rapa-treated, iDC-treated, and combination-treated.
CD4+CD25+Foxp3+ Tregs comprised 7%-8% of CD4+ T cells in control rats. Rapa combined with iDCs enhanced this percentage in the peripheral blood and spleen. However, the levels of Tregs did not significantly change after treatment with Rapa or iDCs alone. The levels of CD4+CD25-Foxp3+ T cells and CD4+CD25+Foxp3- T cells in CD4+ T cells did not significantly change in the combined group. The TGF-beta1 level in serum from the combined group increased significantly compared with the other groups.
A significantly higher percentage of CD4+ CD25+ Foxp3+ Tregs was found in rats treated with allogenic iDCs and a short course of Rapa, along with an increase in the TGF-beta1 level in serum. This improved protocol may be a promising therapeutic strategy to increase Tregs, which are beneficial to the induction of peritransplant tolerance.
Hepatobiliary & pancreatic diseases international: HBPD INT 04/2012; 11(2):203-8. · 1.08 Impact Factor
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ABSTRACT: Bis(7)-tacrine (B7T), a novel dimeric acetyl cholinesterase (AChE) inhibitor, has multiple neuroprotective activities against neuronal damage. However, its therapeutic effects in chronic cerebral ischemia remain unknown. In the present study, adult male Sprague-Dawley rats were subjected with permanent ligation of the bilateral common carotid arteries to investigate the roles of B7T on cognitive function, neuronal apoptosis and neurogenesis in the hippocampus. Results from spatial navigation test showed that chronic cerebral ischemia impaired spatial learning, B7T treatment shorten escape latency of ischemia rats as compared with saline-treated rats. Probe trial test indicated that spatial memory deficit of chronic cerebral ischemic animals was reversed by B7T treatment. Immunohistochemical results showed that B7T reduced neuronal apoptosis in the hippocampal CA1 region as compared with ischemia rats, and B7T treatment increased neurogenesis in the hippocampus. These findings suggest that B7T may exert its neuroprotective effects by inhibiting apoptosis and promoting neurogenesis in 2VO rats.
Neuroscience Letters 03/2012; 512(2):103-8. · 2.11 Impact Factor
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ABSTRACT: Presence of donor-specific antibodies (Abs) is detrimental to posttransplant allograft function. Some sensitized recipients have successfully undergone transplantation after pretransplant conditioning regimen using plasmapheresis and/or intravenous immunoglobulin therapy, but underlying mechanisms that confer such allograft protection are undefined.
We developed a single human leukocyte antigen (HLA)-mismatched heterotopic murine heart transplant model (HLA-A2 into HLA-A2-sensitized-C57BL/6) to determine whether pretreatment of donors with low concentration of HLA class I (W6/32) or control Ab (C1.18.4) will confer protection. Expression levels of survival genes, Bcl-2 and heme oxygenase-1, were analyzed by gene array analysis and quantitative real-time polymerase chain reaction. Expression levels of cytokine panel were analyzed by Luminex. Role of Bcl-2 in the induction of allograft protection was analyzed by silencing the Bcl-2 expression in the donor hearts using a small hairpin (shRNA) specific for Bcl-2.
Control Ab-pretreated hearts were rejected in less than 5 days demonstrating hemorrhage, Ab, and C4 deposition. In contrast, W6/32-pretreated hearts were rejected at 15 days (P<0.05) that was prolonged to 25 days with antilymphocyte serum treatment. W6/32-pretreated hearts on day 5 exhibited increased expression of Bcl-2 (5.5-folds), Bcl-xl (5.5-folds), and heme oxygenase-1 (4.4-folds); decreased expression of ICAM-1, VCAM-1 (3.2-fold), along with reduced levels of cytokines interleukin (IL)-1β (4.4-folds), tumor necrosis factor α (3.7-folds), IL-6 (7.5-folds), IL-12 (2.3-folds) and chemokines monocyte chemotactic protein 1 (4.5-folds), MIG (4.4-folds), MIP-1α (3.4-folds), and IL-8 (3.1-folds). Silencing of Bcl-2 in accommodated hearts before transplant resulted in loss of protection with rejection (9±3 vs. 15±2days, P<0.05).
Pretreatment of hearts with low levels of anti-HLA Abs increases expression of antiapoptotic genes that inhibits caspases, leading to decreased inflammatory cytokines and chemokines, which promote allograft survival.
Transplantation 02/2012; 93(4):364-72. · 4.00 Impact Factor
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ABSTRACT: Steatotic liver grafts tolerate ischemia-reperfusion (I/R) injury poorly, contributing to increased primary graft nonfunction following transplantation. Activation of nuclear factor kappa-B (NFκB) following I/R injury plays a crucial role in activation of pro-inflammatory responses leading to injury.
We evaluated the role of NFκB in steatotic liver injury by using an orthotopic liver transplant (OLT) model in Zucker rats (lean to lean or obese to lean) to define the mechanisms of steatotic liver injury. Obese donors were treated with bortezomib to assess the role of NF-κB in steatotic liver I/R injury. Hepatic levels of NF-κB and pro-inflammatory cytokines were analyzed by ELISA. Serum transaminase levels and histopathological analysis were performed to assess associated graft injury.
I/R injury in steatotic liver results in significant increases in activation of NF-κB (40%, p<0.003), specifically the p65 subunit following transplantation. Steatotic donor pretreatment with proteasome inhibitor bortezomib (0.1mg/kg) resulted in significant reduction in levels of activated NF-κB (0.58±0.18 vs. 1.37±0.06O.D./min/10 μg protein, p<0.003). Bortezomib treatment also reduced expression of pro-inflammatory cytokines MIP-2 compared with control treated steatotic and lean liver transplants respectively (106±17.5 vs. 443.3±49.9 vs. 176±10.6 pg/mL, p=0.02), TNF-α (223.8±29.9 vs. 518.5±66.5 vs. 264.5±30.1 pg/2 μg protein, p=0.003) and IL-1β (6.0±0.91 vs. 19.8±5.2 vs. 5±1.7 pg/10 μg protein, p=0.02) along with a significant reduction in ALT levels (715±71 vs. 3712.5±437.5 vs. 606±286 U/L, p=0.01).
These results suggest that I/R injury in steatotic liver transplantation are associated with exaggerated activation of NFκB subunit p65, leading to an inflammatory mechanism of reperfusion injury and necrosis. Proteasome inhibition in steatotic liver donor reduces NFκB p65 activation and inflammatory I/R injury, improving transplant outcomes of steatotic grafts in a rat model.
Transplant Immunology 01/2012; 26(4):201-6. · 1.46 Impact Factor
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ABSTRACT: The aims of the present study were to explore the effects of: (i) scutellarin (Scu) on protein kinase C (PKC) translocation caused by diabetic conditions in diabetic rat thoracic aorta; and (ii) phorbol-12-myristate-13-acetate (PMA) treatment of cultured thoracic aortic smooth muscle cells. Diabetes was induced in rats by streptozotocin and diabetic rats were divided into two groups: (i) an Scu-treated group, administered 0.1 g/kg Scu by gavage; and (ii) an aminoquanidine (AG)-treated group, which received dietary supplementation of 0.1% AG from Week 1 of diabetes induction. After 10 weeks, rats were killed and thoracic aortic smooth muscle cells were isolated and cultured. Cell fractions were obtained by ultracentrifugation and PKC activity was assayed by ELISA, whereas the distribution of PKC was verified by western immunoblotting. The PKC activity in the membrane fraction of thoracic aortic smooth muscle cells was significantly increased in diabetic compared with control rats, whereas the administration of Scu significantly inhibited this increase. Phorbol myristate acetate (100 nmol/L, 10 min) induced the translocation of the PKCα, βI, βII, δ and ε isoforms, whereas 48 h pretreatment of cells with 1 μmol/L Scu significantly inhibited PMA-induced PKCβI, βII and δ translocation. The results of the present study suggest that Scu inhibits the translocation of PKC in vivo and in vitro and may have value as a drug in the treatment of diabetic complications via its inhibition of PKC βI, βII and δ translocation.
Clinical and Experimental Pharmacology and Physiology 11/2011; 39(2):136-40. · 1.85 Impact Factor
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ABSTRACT: Hepatocyte transplantation has been proposed as an alternative to whole-organ transplantation to support many forms of hepatic insufficiency. Unfortunately, the lack of donor livers makes it difficult to obtain enough viable human hepatocytes for hepatocyte-based therapies. Therefore, it is urgent to find new ways to provide ample hepatocytes. Induced pluripotent stem (iPS) cells, a breakthrough in stem cell research, may terminate these hinders for cell transplantation. For the promise of iPS cells to be realized in liver diseases, it is necessary to determine if and how efficient they can be differentiated into functional hepatocytes.
In this study, we directly compared the hepatic-differentiation capacity of mouse iPS cells and embryonic stem (ES) cells with three different induction approaches: conditions via embryonic body (EB) formation plus cytokines, conditions by combination of dimethyl sulfoxide and sodium butyrate and chemically defined, serum free monolayer conditions. Among these three induction conditions, more homogenous populations can be promoted under chemically defined, serum free conditions. The cells generated under these conditions exhibited hepatic functions in vitro, including glycogen storage, indocynine green (ICG) uptake and release as well as urea secretion. Although efficient hepatocytes differentiation from mouse iPS cells were observed, mouse iPS cells showed relatively lower hepatic induction efficiency compared with mouse ES cells.
Mouse iPS cells would be efficiently differentiated into functional hepatocytes in vitro, which may be helpful in facilitating the development of hepatocytes for transplantation and for research on drug discovery.
We demonstrate that mouse iPS cells retain full potential for fetal liver development and describe procedures that facilitates the efficient generation of highly differentiated human hepatocyte-like cells from iPS cells in vitro.
Chinese medical journal 11/2011; 124(22):3786-93. · 0.86 Impact Factor
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ABSTRACT: To evaluate the effect of noninvasive Bi-level Positive Airway Pressure (BiPAP) ventilation on the severe influenza A virus associated with pneumonia and acute respiratory failure (ARF).
Based on conventional therapy via face mask using BiPAP ventilator positive airway pressure ventilation in the treatment of severe pneumonia caused by influenza A (H1N1) virus with acute respiratory failure (ARF) in 18 cases, we observed and evaluated the therapeutic effects.
PaO2 and SaO2 before and after treatment were (48.85 ± 12.15)mmHg, (68.56 ± 16.25) mmHg and (80 ± 6)%, (92 ± 5)%, respectively. The results were significantly different (P<0.05) before and after treatment. Endotracheal intubation rate was 25% (6/24) and case-fatality rate was 8.3% (2/24).
BiPAP ventilator airway pressure by face mask ventilation can reduce the rate of endotracheal intubation in the treatment of severe pneumonia caused by influenza A (H1N1) virus in acute respiratory failure. It could be an effective approach in the emergency treatment with clinical value.
Journal of thoracic disease. 09/2010; 2(3):134-7.
