[Show abstract][Hide abstract] ABSTRACT: Allogeneic transplant rejection is currently a major problem encountered during organ transplantation. The dendritic cell (DC) is the most effective powerful known professional antigen-presenting cell, and recent studies have found that DCs can also induce immune tolerance, and avoid or reduce the degree of transplant rejection. The aim of this study was to evaluate the effect of transfused immature CD4(+) DCs on renal allografts in the rat model.
In this study, we induced CD4(+) immature DCs from rat bone marrow cells by a cytokine cocktail. The immature CD4(+) DCs were identified by morphological analysis and then the suppressive activity of these cells conditioned with donor kidney antigen was evaluated in vitro and in vivo.
Immature CD4(+) DCs conditioned with donor kidney antigen possessed immunosuppressive activity in vitro and they were able to prolong renal transplant survival in an allograft rat model in vivo.
Our study provides new information on efficacious renal transplantation, which might be useful for understanding the function of immature CD4(+) DCs in modulating renal transplant rejection and improving clinical outcome in future studies.
No preview · Article · Jul 2012 · Chinese medical journal
[Show abstract][Hide abstract] ABSTRACT: We used a model of vascularized thymus lobes as a whole isolated organ transplantation in rats.
Male Fisher rats (F344, RT11v1; n = 10) and male homozygous Rowett nude rats (rnu/rnu; n = 10) were used as donors and recipients, respectively. Both vascular lobes of the thymus as a whole isolated organ were heterotopically transplanted to the neck of recipients. The right common carotid artery of the donor thymus was anastomosed end-to-end to the homonymous artery of the recipient. The anterior vena cava and the left brachiocephalic vein of the donor thymus were anastomosed end-to-side to the right and left external jugular veins of the recipient, respectively. Histological examination was used to monitor graft viability; graft function was assessed using flow cytometry (FCM) and immunologic effects by skin grafts in vivo.
All recipients survived. Preparation of the donors and recipients took 35.6 ± 5.5 minutes and 60.3 ± 15.1 minutes, respectively. The blood supply to the thymus graft was patent. Histology of the thymus on postoperative days 14, 56, and 112 revealed viable grafts with preserved microarchitecture. FCM analysis showed 37.18 ± 11.1% CD3+ T cells at day 21 after transplantation. Skin grafts from F344 and Rowett rats survived 8-10 and more than 30 days, respectively, whereas all third-party Sprague Dawley grafts were rejected within 5 days.
We developed a novel model of isolated, direct vascularized whole thymus transplantation in nude rats, in which both lobes of the fully vascularized thymus were harvested en bloc for successful transplantation.
Preview · Article · Jun 2012 · Transplantation Proceedings
[Show abstract][Hide abstract] ABSTRACT: Nephrotoxic serum nephritis (NSN) is a well-established animal model of glomerulonephritis, a frequent clinical condition with a high mortality rate owing to the ineffectiveness of current therapies. Mesenchymal stem cells (MSCs) are adult stem cells with potential as novel therapies in regenerative medicine owing to the absence of allogenic rejection. Glial cell-derived neurotrophic factor (GDNF) acts as a morphogen in kidney development. The therapeutic effectiveness of bone marrow MSCs overexpressing GDNF (GDNF-MSCs) was evaluated in an NSN rat model. An adenoviral vector was used to transduce MSCs with GDNF and a green fluorescent protein reporter gene. Then, GDNF-MSCs were injected into NSN rats via the renal artery. The influence of GDNF on renal injury was assessed. The location of GDNF-MSCs in kidneys was detected using fluorescence microscopy, cells were counted, and kidney function was measured. Infusion of GNDF-MSCs enhanced the recovery of renal function in NSN rats. MSCs were detected in the kidney cortex after injection. Compared with control MSCs, GDNF-MSCs led to significantly better renal function and injury recovery in NSN rats. GDNF has a positive effect on MSC differentiation in renal tissue. Owing to their highly renoprotective capacity, GDNF-MSCs represent a possible novel cell-based paradigm for treatment of glomerulonephritis.
No preview · Article · Mar 2012 · Cell Biochemistry and Function
[Show abstract][Hide abstract] ABSTRACT: Ginsenoside Rg1, an active component of high abundance in ginseng, has recently been reported to possess neuroprotective properties and also identified as a potent phytoestrogen. However, it is unknown whether Rg1 intervenes in amyloid precursor protein (APP) processing, and whether such intervention is associated with its estrogenic activity. Using human platelets, this study demonstrated that Rg1 promoted α-secretase cleavage of APP via estrogenic activity. The mitogen-activated protein kinases (MAPK)/extracellular signal-regulated kinases (ERK) pathway may be involved in the effect of Rg1 on APP metabolism as a downstream effector of estrogen receptor (ER) extranuclear signaling. Estrogen withdrawal is a risk factor for the onset of Alzheimer's disease (AD). Rg1 exerts estrogenic activity in APP processing in platelets supporting the use of this compound in the prevention of AD, in particular in postmenopausal females.
[Show abstract][Hide abstract] ABSTRACT: The graft-versus-tumor (GVT) effect of T cells induced by tumor antigen-pulsed CD8α(+) dendritic cells (DCs) in vitro was investigated in this study. Immature CD8α(+) DCs were prepared from C57BL/6 (H-2(b)) bone marrow cells by using a cytokine cocktail. On the 3rd day of culture, CD8α(+) DCs were pulsed by allogeneic (Balb/c, H-2(d)) EL9611 leukemia antigen, or RM-1 syngeneic prostate cancer antigen, with the concentration series of 0, 2.5, 5.0, 10.0, 20.0 μg/mL, respectively, then antigen-loaded immature CD8α(+) DCs were co-cultured with syngeneic T cells according to the DC/T ratio of 1:1, 2:1 and 4:1. T cell proliferation was measured by MTT assay. Cytokines including interferon gamma (IFN-γ) and interleukin-10 (IL-10) in CD8α(+) DCs and T co-culture supernatant were detected by using ELISA. Cytotoxic effect of antigen-specific T cells was tested by LDH release assay. Conventional mature DCs (mDCs) induced from C57BL/6 (H-2(b)) bone marrow cells by using granulocyte-macrophage colony stimulating factor (GM-CSF) and interleukin-4 (IL-4) served as a control. The results showed that the proliferative activity of T cells stimulated by CD8α(+) DCs loaded with allogeneic or syngeneic tumor antigen was augmented with the CD8α(+) DC/T ratio increased (P<0.05). When antigen concentration ≤ 5 μg/mL and CD8α(+) DC/T ratio ≤ 2:1, the ability of CD8α(+) DCs to stimulate T cell proliferation was higher than mDC control in allogeneic tumor antigen-pulsed groups (P<0.05), but not in syngeneic tumor antigen-pulsed groups (P>0.05). The level of IFN-γ and IL-10 in CD8α(+) DCs and T cell co-culture supernatant were increased in both allogeneic and syngeneic antigen-pulsed groups (P<0.05), and the cytokine level was higher in allogeneic antigen-pulsed groups than in syngeneic antigen groups when the CD8α(+) DC/T was 1:1 or 2:1 (P<0.05). There existed a negative correlation between the level of IL-10 and T cell proliferation. T cell cytotoxicity assay showed that when CD8α(+) DCs were pulsed with allogeneic tumor antigen, the maximal T cell killing efficiency could reach (100±7.7)%, whereas syngeneic tumor antigen-pulsed group had only (65.0±3.4)%. It was concluded that syngeneic and allogeneic tumor antigen-pulsed immature CD8α(+) DCs could stimulate T cells to exert the GVT effect in vitro, and the GVT effect was more obvious with allogeneic tumor antigen than with syngeneic tumor antigen. The optimal condition was low allogeneic tumor antigen pulsation (≤ 5 μg/mL) and low CD8α(+) DC/T ratio (1:1 and 2:1).
No preview · Article · Dec 2011 · Journal of Huazhong University of Science and Technology
[Show abstract][Hide abstract] ABSTRACT: Thymokidney has been reported as an approach for a vascularized thymus for transplantation to induce donor specific tolerance. A completely thymectomized model which ensures that the obtained thymus is not injured has not been developed yet and it would be useful for evaluating autologous thymokidney function in rats.
Adult Sprague-Dawley male rats weighing 150 - 300 g (n = 30) underwent non-invasive intubation with the assistance of an improved self-made wedge-shaped cannula made from a 2-ml plastic syringe and transillumination from the anterior tracheal area by an operation spotlight. The rats then received a thoracotomy while their breathing was supported by a small animal ventilator, and both lobes of the thymus were entirely extirpated under a 10× microscope. The postoperative survival rate of the rats was recorded, and changes in the T-cell reservoir from 9 of 30 rats within 21 days after surgery were monitored using flow cytometry. The complete thymectomy rate was confirmed by autopsy and histological examination on 21 days post-operation.
The postoperative survival rate of rats was 100%. The exsected thymus was free of injury and the rate of complete thymectomy was 100%.
This model has a stable survival rate and complete thymectomy is able to be achieved. The obtained thymus tissue is free of injury and can be used for transplantation.
Preview · Article · Sep 2011 · Chinese medical journal
[Show abstract][Hide abstract] ABSTRACT: For the renal transplant recipients, anemia is one of the common complications and becomes a major medical issue before transplantation. Haemoglobin (Hb) is used as a prognostic indicator, although the optimal pre-transplantation Hb concentration associated with positive prognosis is still controversial. The aim of this study was to detect the optimal Hb concentration on predicting the graft survival and function.
A retrospective cohort study was conducted by reviewing the medical records of the patients who received renal transplantations at our center from January 2004 to June 2008. Patients were divided into two groups: high Hb group (≥ 100 g/L, n = 79) and low Hb group (< 100 g/L, n = 63). There was no significant difference between the two groups regarding sex, age, blood type and tissue types. Renal function among the two groups was measured and compared. Panel reacting antigens (PRA) of all the recipients were negative. The effect of preoperative hemoglobin concentration on the postoperative renal function recovery in both groups was further analyzed.
A total of 14 acute rejection episodes occurred, including 5 patients in the high Hb group (7.9%) and 9 in the low Hb group (11.4%, P > 0.05). The serum creatinine level at one-year post-transplantation of the low Hb group was significantly higher than that of the high Hb group ((117.8 ± 36.3) µmol/L vs. (103.1 ± 35.5) µmol/L, P < 0.05). For one-year actuarial patient and graft survival, incidence of delayed graft function (DGF), serum creatinine concentrations at 1, 3, 6 months post-transplantation, the incidence of cytomegalovirus (CMV) infection, post-transplantation anemia (PTA) and post-transplantation diabetes mellitus (PTDM) of both groups, there were no statistically significant differences.
Pre-transplantation Hb concentration has significant effect on one-year creatinine concentration, but can not significantly affect acute rejection episodes, DGF, PTA, CMV infection and PTDM.
Preview · Article · Apr 2011 · Chinese medical journal
[Show abstract][Hide abstract] ABSTRACT: The prospects of using immature CD8a(+) dendritic cells (DC2) to establish transplant immunologic tolerance and treatments for autoimmune diseases in the future are promising. However, the methods for inducing DC2 are still being explored. The present study was aimed to investigate the optimal in vitro conditions for preparing large numbers of predominant DC2 from murine bone marrow cells.
Three groups of bone marrow cells cultured under different conditions were examined, namely a cytokine-induced experimental group (cytokine group), a control group with a low concentration of granulocyte-macrophage colony stimulating factor (GM-CSF, low GM-CSF group) and a control group without endogenous cytokines. The cytokine group was cultured with 5 ng/ml GM-CSF, 25 ng/ml Flt3 ligand (Flt3L), 20 ng/ml interleukin 4 (IL-4) and 100 ng/ml stem cell factor (SCF). The low GM-CSF control group was cultured with 0.4 ng/ml GM-CSF, 25 ng/ml Flt3L and 100 ng/ml SCF, without IL-4. The control group without exogenous cytokines was cultured without additional cytokines. All cells were cultured at 37 degrees C under 5% CO2. On days 3, 7 and 16, 4-color flow cytometry was carried out to analyze the cell phenotypes, and the total cell numbers were counted to analyze the cell yields. Phase-contrast microscopy was used to observe the cell morphologies.
The cytokine group exhibited higher proportions of typical immature CD8a(+) DC, especially on day 3, but the total cell number and DC2 proportion decreased during prolonged culture. The low GM-CSF control group showed the same tendencies as the cytokine group on days 16 and 22, but produced higher total cell numbers (P<0.05) with lower DC2 proportions and cell numbers. The control group without exogenous cytokines spontaneously generated a certain proportion of DC2, but with low total cell and DC2 numbers that decreased rapidly, especially during prolonged culture (days 7 and 16, P<0.05).
Culture in the presence of 5 ng/ml GM-CSF, 25 ng/ml Flt3L, 20 ng/ml IL-4 and 100 ng/ml SCF can rapidly induce large quantities of predominant immature CD8a(+) DC from murine bone marrow cells. Therefore, these represent optimal culture conditions for preparing murine immature DC2 in vitro.
No preview · Article · Mar 2009 · Chinese medical journal