Zhiren Fu

Anti-ICAM-1 antibody and CTLA-4Ig synergistically enhance immature dendritic cells to induce donor-specific immune tolerance in vivo.

Immature dendritic cells (DC) have been demonstrated to induce T-cell hyporesponsiveness in vitro and immune tolerance in vivo. However, immature DC (iDC) may become mature once infused in vivo, thus limiting the prolongation of the allograft survival. Considering that mature DC express high level of B7, intercellular adhesion molecule-1 (ICAM-1), and T-cell activation needs costimulation signals provided by DC, we selected anti-ICAM-1 mAb and cytotoxic T lymphocyte antigen-4Ig fusion protein (CTLA-4Ig) for in vivo administration to block costimulation pathways in order to further improve the efficacy of iDC to induce immune tolerance. Seven days before allogeneic cardiac transplantations, the recipients were intravenously (i.v.) pretreated of donor-derived iDC with or without simultaneous injections of anti-ICAM-1 mAb and CTLA-4Ig. CTLA-4Ig or anti-ICAM-1 mAb administration alone resulted in significant prolongation of cardiac allograft survival induced by iDC. When used simultaneously, CTLA-4Ig and anti-ICAM-1 mAb induced permanent allografts acceptance even in 90% recipients. The recipients could keep the skin alive for a longer time in the donor-specific second transplantation, but no effect was observed on the skin from C3H third-party mice. The efficient induction of donor-specific tolerance observed above may be related to the more potent inhibition of donor-specific T-cell responses including cytotoxicity activity, Th1 cytokines production, and alloantibody production by the combined use of anti-ICAM-1 mAb and CTLA-4Ig. Our data suggest that anti-ICAM-1 antibody and CTLA-4Ig can synergistically enhance iDC to induce donor-specific immune tolerance in vivo.

Effective induction of immune tolerance by portal venous infusion with IL-10 gene-modified immature dendritic cells leading to prolongation of allograft survival

Dendritic cells (DC) not only initiate T cell responses, but are also involved in the induction of tolerance. The functional properties of DC are strictly dependent on their state of maturation. It has been shown that immature DC can induce immune tolerance and prolong allograft survival. Interleukin-10 (IL-10) is an important immunosuppressive cytokine which inhibits maturation and function of DC. In order to improve the tolerogenicity of DC, we and others showed that adenovirus vectors can effectively mediate IL-10 genetic modification of DC, and IL-10 genetic modification can inhibit MHC II, B7.2, and CD40 expression, IL-12 secretion and the T cell stimulatory capacity of DC. The primary aim of this study is to examine the in vivo effects of this approach on allograft survival in a murine cardiac allograft transplantation model. To our surprise, we observed that infusion of immature DC genetically modified to express IL-10 (DC-IL-10) via the tail vein could not prolong allograft survival in the recipients, but shortened their survival. More interestingly, portal venous infusion of DC-IL-10 markedly prolonged allograft survival. The diverse effects of DC-IL-10 infusion through different routes may be due to the different immune responses to alloantigens in recipients that received DC-IL-10 via either the portal or the tail vein. Decreased cytotoxicity, polarization of Th2 response, poor T cell stimulating activity of liver DC and enhanced incidence of donor DC in the recipients may contribute to the more efficient prolongation of allograft survival observed after portal venous infusion of DC-IL-10. These results suggest that portal venous infusion may be an effective approach for immature DC to induce immune tolerance or hyporesponsiveness against donor antigens, and prolong allograft survival.

Postreperfusion syndrome during orthotopic liver transplantation: a single-center experience

BACKGROUND Marked hemodynamic alteration, commonly referred to as postreperfusion syndrome (PRS), often occurs after revascularization of the donor organ during orthotopic liver transplantation (OLT) and is associated with poor outcomes. This study aimed to investigate the incidence, predictive factors and clinical outcomes of PRS in Chinese patients following OLT at a liver transplantation center in China. METHODS Over a 5-year period, 330 consecutive patients who had undergone OLT for hepatocellular carcinoma or cirrhosis were included in this retrospective study. PRS was defined as a >30% decrease in the mean arterial pressure compared with that before revascularization for more than 1 minute during the first 5 minutes of graft reperfusion. The patients were divided into 2 groups according to the development of PRS: group 1 (patients with PRS, n=56) and group 2 (patients without PRS, n=274). The demographic characteristics, operative and postoperative courses, and outcomes of the patients were analyzed using SPSS version 18.0. RESULTS Multivariate regression analysis showed that left ventricular diastolic dysfunction determined by echocardiography and prolonged cold ischemia time were the independent risk factors for PRS. More patients in group 1 showed postoperative renal dysfunction than those in group 2 (19.23% vs 8.4%). Moreover, patients in group 1 also had higher intraoperative (7.14% vs 0%) and postoperative mortalities (26.92% vs 12.04%). CONCLUSION Left ventricular diastolic dysfunction and prolonged cold ischemia time contribute to a high incidence of PRS, which is associated with adverse outcomes in Chinese patients following OLT.

Hepatoprotective Action of Radix Paeoniae Rubra Aqueous Extract against CCl4-Induced Hepatic Damage

In the present study the capacity of Radix Paeoniae Rubra aqueous extract (RPRAE) as an antioxidant to protect against carbon tetrachloride (CCl4)-induced oxidative stress and hepatotoxicity in Wistar rats was investigated. Six groups of rats were used. Radix Paeoniae Rubra aqueous extract (100 or 200 or 300 mg/kg of bw) or bifendate (100 mg/kg of bw) were given daily by gavage to the animals on 28 consecutive days to elucidate the protective effects against CCl4-induced hepatotoxicity. The 20% CCl4/olive oil was gavage of gastric tube twice a week (on the third and seventh days of each week). The animals of normal control group were given only vehicle. The animals of CCl4-treated group were administered with CCl4 twice a week (on the third and seventh days of each week) and with vehicle on rest of the days. The test materials were found effective as hepatoprotective agents, as evidenced by plasma and liver biochemical parameters. Therefore, the results of this study show that Radix Paeoniae Rubra aqueous extract can protect the liver against CCl4-induced oxidative damage in rats, and the hepatoprotective effects might be correlated with its antioxidant and free radical scavenger effects.

A tissue-engineered subcutaneous pancreatic cancer model for antitumor drug evaluation.

The traditional xenograft subcutaneous pancreatic cancer model is notorious for its low incidence of tumor formation, inconsistent results for the chemotherapeutic effects of drug molecules of interest, and a poor predictive capability for the clinical efficacy of novel drugs. These drawbacks are attributed to a variety of factors, including inoculation of heterogeneous tumor cells from patients with different pathological histories, and use of poorly defined Matrigel®. In this study, we aimed to tissue-engineer a pancreatic cancer model that could readily cultivate a pancreatic tumor derived from highly homogenous CD24+CD44+ pancreatic cancer stem cells delivered by a well defined electrospun scaffold of poly(glycolide-co-trimethylene carbonate) and gelatin. The scaffold supported in vitro tumorigenesis from CD24+CD44+ cancer stem cells for up to 7 days without inducing apoptosis. Moreover, CD24+CD44+ cancer stem cells delivered by the scaffold grew into a native-like mature pancreatic tumor within 8 weeks in vivo and exhibited accelerated tumorigenesis as well as a higher incidence of tumor formation than the traditional model. In the scaffold model, we discovered that oxaliplatin-gemcitabine (OXA-GEM), a chemotherapeutic regimen, induced tumor regression whereas gemcitabine alone only capped tumor growth. The mechanistic study attributed the superior antitumorigenic performance of OXA-GEM to its ability to induce apoptosis of CD24+CD44+ cancer stem cells. Compared with the traditional model, the scaffold model demonstrated a higher incidence of tumor formation and accelerated tumor growth. Use of a tiny population of highly homogenous CD24+CD44+ cancer stem cells delivered by a well defined scaffold greatly reduces the variability associated with the traditional model, which uses a heterogeneous tumor cell population and poorly defined Matrigel. The scaffold model is a robust platform for investigating the antitumorigenesis mechanism of novel chemotherapeutic drugs with a special focus on cancer stem cells.

Sinomenine pretreatment attenuates cold ischemia/reperfusion injury in rats: The role of heme oxygenase-1

Ischemia/reperfusion (I/R) injury can be characterized as an inflammatory response including recruitment of inflammatory cells to a post-ischemic organ or tissue and a cascade of mediators. Sinomenine (SIN), a pure alkaloid extracted from the Chinese medical plant Sinomenium acutum, has been used to treat various inflammatory diseases including rheumatism and arthritis. However, whether SIN can attenuate I/R injury has not previously been examined. Using a syngeneic orthotopic liver transplantation model in rats, we investigated the effect of SIN on hepatic I/R injury, in particular its effect on heme oxygenase-1 (HO-1) induction and its hepatocellular protective effect. To our knowledge, our results were the first to show that: (a) SIN pretreatment was able to induce HO-1 expression in donor livers in a dose dependent manner; (b) SIN pretreatment protected the liver graft from cold I/R injury; and (c) the protective effect of SIN was, at least in part, mediated by HO-1, as proved by the fact that inhibiting HO-1 activity with zinc protoporphyrin (ZnPP) reduced the protection. Thus, SIN deserves further exploration as a novel agent to attenuate I/R injury.

Complement C3 deficiency prevent against the onset of streptozotocin-induced autoimmune diabetes involving expansion of regulatory T cells

Recent studies have demonstrated that complement contributes to the development of autoimmune diabetes. However, the mechanisms remain unknown. Herein, using a model of streptozotocin (STZ)-induced diabetes, we found the presence of immune tolerance to self islet in complement C3-deficient mice after STZ. Higher number of CD4+CD25+ regulatory T cells (Tregs) with characteristics of expressing Foxp3 was observed in C3-/- mice. These C3-/- Tregs exhibited enhanced suppressive capacity to effector cell proliferation. The central role of Tregs was further evidenced by that depleting these cells using anti-CD25 antibody dramatically abrogated the preventive effects of C3 deficiency on STZ-induced diabetes. Importantly, transforming growth factor-β (TGF-β) was a key factor for Treg-mediated immune suppression as blocking TGF-β activity reversed suppressive capacity of Tregs in vitro and diabetes-resistant effects of C3 deficiency in vivo. These findings suggest that resistance to overt diabetes in STZ-treated C3-/- mice involves a population of Tregs in TGF-β-dependent manner.

Adjuvant treatment suppresses IL-17 production by T cell-independent myeloid sources in nonobese diabetic mice.

Recent studies have shown that Th17 cells, as a distinct lineage from Th1 and Th2 subsets, play an obligatory role in the pathogenesis of autoimmune diseases. It is well known that immunotherapy with Complete Freunds adjuvant (CFA) is effective in preventing from the onset of autoimmune diabetes in nonobese diabetic (NOD) mice. In the present study, we investigated whether CFA treatment restrained Th17 development and down-regulated Th17-related cytokine production in NOD mice. Th17-related cytokines (i.e. IL-17A, IL-17F, IL-21, IL-22, IL-23, IL-6, TGF-beta) production in splenocytes was decreased dramatically on day 18 following CFA immunization. This effect was also observed at 10 and 20 week after adjuvant treatment. Injection of IL-17 into CFA-treated diabetes-free mice led to occurrence of overt diabetes, indicating that therapeutic effects of adjuvant treatment may be partially due to suppressing Th17 commitment. Interestingly, the main producer of IL-17 resided in a population of myeloid cells, which negatively expressed makers of neutrophil or macrophages. IL-23 stimulation did not alter the distribution of IL-17 in myeloid cells. Furthermore, this pattern of IL-17 expression was also present in Balb/c and C57BL/6 strains. These findings may have important implications for understanding of mechanisms underlying adjuvant treatment on autoimmune diseases.

The relationship between adenosine triphosphate within CD4+ T lymphocytes and acute rejection after liver transplantation

Dong J‐Y, Yin H, Li R‐D, Ding G‐S, Fu Z‐R, Wu Y‐M, Wang Z‐X. The relationship between adenosine triphosphate within CD4+ T lymphocytes and acute rejection after liver transplantation.
Clin Transplant 2011: 25: E292–E296.

Astilbin Suppresses Acute Heart Allograft Rejection by Inhibiting Maturation and Function of Dendritic Cells in Mice

The effect of astilbin on acute graft rejection was investigated in C57BL/6 mice carrying BALB/c hearts heterotopically transplanted into the neck vessels. Daily treatment with astilbin (50, 125, or 250 mg/kg intraperitoneally) significantly prolonged the survival of grafts in a dose-dependent manner, when cyclosporine (CsA; 5 mg/kg) was co-administered with astilbin (250 mg/kg), there was more potent immunosuppression than that solely achieved by 20 mg/kg CsA. Addition of 10 mg/mL astilbin significantly inhibited the proliferation and activation of T cells, as determined by (3)H-thymidine deoxyribose uptake, Western blots for nuclear factor κB and p38, and 1-way mixed lymphocyte reactions (MLR). Mature and antigen-presenting functions of dendritic cells (DCs) also were inhibited by astilbin (10 mg/mL), as determined by morphologic observations, flow cytometry, and MLR. These observations suggested that astilbin is a potential candidate for immunosuppressive therapy after heart engraftment. Inhibiting the maturation and antigen-presenting function of DCs and thus preventing T-cells activation is a possible mechanism underlying its inhibitory effects on acute heart allograft rejection.