Jina Wang

Prediction of Acute Cellular Renal Allograft Rejection by Urinary Metabolomics Using MALDI-FTMS

The present study investigated small molecule analysis of urinary samples as a noninvasive method to detect acute cellular renal allograft rejection. Matrix-assisted laser desorption/ionization Fourier transform mass spectrometry (MALDI-FTMS) was used to analyze 15 urinary samples from transplant patients with different grades of biopsy showing improved clinical acute cellular rejection (ACR) and 24 urinary samples from 8 transplant patients without evidence of rejection. Seven small molecules demonstrated highly successful diagnostic performance (m/z): 278.1 (t = 3.398, p = 0.004), 293.0 (t = 2.169, p = 0.048), 294.1 (t = 2.154, p = 0.05), 382.2 (t = 2.961, p = 0.010), 383.3 (t = 2.270, p = 0.040), 402.2 (t = 2.994, p = 0.010), 424.0 (t = 2.644, p = 0.019). Kidney transplant patients with ACR could be distinguished from those without ACR using four individual small molecules with a specificity of 100%. In conclusion, the combination of MALDI-FTMS technology with a clear definition of patient groups can detect urine small molecule associated with ACR.

Naked caspase 3 small interfering RNA is effective in cold preservation but not in autotransplantation of porcine kidneys.

BACKGROUND Caspase 3 associated with apoptosis and inflammation plays a key role in ischemia-reperfusion injury. The efficacy of naked caspase 3 small interfering RNA (siRNA) has been proved in an isolated porcine kidney perfusion model but not in autotransplantation. MATERIALS AND METHODS The left kidney was retrieved from mini pigs and infused with the University of Wisconsin solution with or without 0.3mg of caspase 3 siRNA into the renal artery with the renal artery and vein clamped for 24-h cold storage (CS). After right nephrectomy, the left kidney was autotransplanted into the right for 48 h without systemic treatment of siRNA. RESULTS Fluorescent dye-labeled caspase 3 siRNA was visualized in the post-CS kidneys but was weakened after transplantation. The expression of caspase 3 messenger RNA and precursor was downregulated by siRNA in the post-CS kidneys. In the siRNA-preserved posttransplant kidneys, however, the caspase 3 messenger RNA and active subunit were upregulated with further decreased precursor but increased active caspase 3+ cells, apoptotic cells, and myeloperoxidase+ cells. Moreover, the renal tissue damage was aggravated by siRNA, whereas the renal function was not significantly changed. CONCLUSIONS Naked caspase 3 siRNA administered into the kidney was effective in cold preservation but not enough to protect posttransplant kidneys, which might be because of systemic complementary responses overcoming local effects.

Urinary Metabolomics in Monitoring Acute Tubular Injury of Renal Allografts: A Preliminary Report

Acute tubular injury (ATI) is very common in biopsy specimens from renal allografts that suffer from delayed graft function (DGF) or dysfunction. Currently there are few reports on investigating small molecule metabolites in urine samples from transplant recipients as a noninvasive method to predict the ATI of renal allografts instead of an allograft biopsy. In our study matrix-assisted laser desorption/ionization Fourier transform mass spectrometry (MALDI-FTMS) was used to analyze small molecule metabolites in urine samples from renal transplant recipients with biopsy-proven slight ATI or moderate ATI or acute tubular necrosis (ATN). To evaluate the ATI-specific value of those small molecules, we applied the Principal Component Analysis (PCA) program. Mass spectra data were imported into the PCA, where loading graphs were constructed to express the constituents of the urine samples. Slight ATI, moderate ATI, or ATN of renal allografts were separated obviously in the loading graph. The position of urine samples in the graph may reflect the tubular injury status of allografts. A farther apart point from the original site may mean the allograft suffered from more severe ATI (even ATN), and vice versa. Detection of small molecule metabolites in urine samples of recipients through MALDI-FTMS may offer a promising noninvasive, high throughput, rapid tool to predict ATI/ATN of renal allografts.

Estimation of Mycophenolic Acid Area Under the Curve With Limited-Sampling Strategy in Chinese Renal Transplant Recipients Receiving Enteric-Coated Mycophenolate Sodium

Background: The enteric-coated mycophenolate sodium (EC-MPS), whose active constituent is mycophenolic acid (MPA), has been widely clinically used for organ transplant recipients. However, its absorption is delayed due to its special designed dosage form, which results in difficulty to monitor the exposure of the MPA in patients receiving the EC-MPS. This study was aimed at developing a relatively practical and precise model with limited sampling strategy to estimate the 12-hour area under the concentration–time curve (AUC0–12 h) of MPA for Chinese renal transplant recipients receiving EC-MPS. Methods: A total of 36 Chinese renal transplant recipients receiving the EC-MPS and tacrolimus were recruited in this study. The time point was 2 weeks after the transplantation for all the patients. The MPA concentrations were measured with enzyme-multiplied immunoassay technique for 11 blood specimens collected predose and at 0.5, 1, 1.5, 2, 2.5, 3, 4, 6, 8, and 12 hours after the morning dose of EC-MPS. The measured AUC was calculated with these 11 points of MPA concentrations with the linear trapezoidal rule. Limited sampling strategy was used to develop models for estimated AUC in the model group (n = 18). The bias and precision of different models were evaluated in the validation group (n = 18). Results: C4 showed the strongest correlation with the measured AUC. The best 3 time point equation was 6.629 + 8.029 × C0 + 0.592 × C3 + 1.786 × C4 (R2 = 0.910; P < 0.001), whereas the best 4 time point equation was 3.132 + 5.337 × C0 + 0.735 × C3 + 1.783 × C4 + 3.065 × C8 (R2 = 0.959; P < 0.001). When evaluated in the validation group, the 4 time point model had a much better performance than the 3 time point model: for the 4 time point model: R2 = 0.873, bias = 0.505 [95% confidence interval (CI), −10.159 to 11.170], precision = 13.370 (95% CI, 5.186–21.555), and 77.8% of estimated AUCs was within 85%–115% of the measured AUCs; for the 3 time point model: R2 = 0.573, bias = 6.196 (95% CI, −10.627 to 23.018), precision = 21.286 (95% CI, 8.079–34.492), and 50.0% of estimated AUCs was within 85%–115% of the measured AUCs. Conclusions: It demanded at least 4 time points to develop a relatively reliable model to estimate the exposure of MPA in renal transplant recipients receiving the EC-MPS. The long time span needed restricted its application, especially for the outpatients, but it could be a useful tool to guide the personalized prescription for the inpatients.

Modulation of allogeneic CD8+ T-cell response by DZNep controls GVHD while preserving hematopoietic chimerism.

Background Allogeneic hematopoietic stem cell transplantation (allo-HSCT) combined with solid-organ transplantation is a feasible method to achieve long-lasting organ allograft tolerance through the induction of hematopoietic chimerism in recipients. However, the allo-HSCT engraftment puts recipients at risk of life-threatening graft-versus-host disease (GVHD). Novel immunomodulatory approaches are required to effectively control GVHD while preserving the status of hematopoietic chimerism. We have reported that histone methylation inhibitor 3-deazaneplanocin A (DZNep) can control ongoing GVHD in mice by selectively inducing apoptosis of alloreactive effector T cells. Methods Using donor-derived CD8+ T cell-mediated mouse GVHD model, we further investigated the effect of in vivo administration of DZNep on allogeneic CD8+ T cell response and the hematopoietic chimerism in recipients. Results We found that DZNep delayed the in vivo proliferation of donor-derived alloreactive CD8+ T cells and also reduced the interleukin-2 production by these T cells. Moreover, DZNep treatment resulted in a significant decrease of interferon-&ggr;, tumor necrosis factor-&agr;, granzyme B, TRAIL, and Fas ligand expressing donor-derived CD8+ T cells, suggesting a multilevel modulation role on T-cell survival and effect in vivo. Notably, DZNep treatment did not hamper the generation of hematopoietic chimerism in recipients. Conclusions These findings suggest that modulation of histone methylation through DZNep may be a potential strategy for the induction of hematopoietic chimerism to achieve donor-specific organ allograft tolerance through donor allo-HSCT combined with solid-organ transplantation.

Inhibition of histone methyltransferase EZH2 ameliorates early acute renal allograft rejection in rats

BackgroundAlthough histone methyltransferases EZH2 has been proved to have significant regulatory effect on the immune rejection after hematopoietic stem cell transplantation, its role in solid-organ transplantation remains uncovered. In this study, we investigate whether histone methylation regulation can impact renal allograft rejection in rat models.ResultsAllogeneic rat renal transplantation model (Wistar to Lewis) was established, and the recipients were administrated with EZH2 inhibitor DZNep after transplantation. Renal allografts and peripheral blood were collected on day 5 after transplantation for histological examination and mechanism investigation. We found that inhibition of EZH2 by DZNep after transplantation significantly ameliorated acute rejection (AR), with decreased histological injury and reduced inflammatory infiltration in renal allografts. Attenuation of AR was due to the prohibited activation of alloreactive T cells, the subsequent impaired production of inflammatory cytokines, and also the elevated apoptosis of alloreactive T cells in both renal allografts and periphery. However, inhibition of EZH2 did not increase the regulatory T cells during the AR.ConclusionsDisruption of EZH2 by DZNep suppressed the immune responses of alloreactive T cells and ameliorated AR of renal allografts. This suggests a therapeutic potential of targeting histone methyltransferases EZH2 in treating allograft rejection after solid organ transplantation.

GC/MS-based urine metabolomics analysis of renal allograft recipients with acute rejection

BackgroundAcute renal allograft rejection is a common complication after renal transplantation that often leads to chronic rejection and ultimate graft loss. While renal allograft biopsy remains the gold standard for diagnosis of acute rejection, the possibility of biopsy-associated complications cannot be overlooked. The development of noninvasive methods for accurate detection of acute renal allograft rejection is thus of significant clinical importance.MethodsGas chromatography–mass spectrometry (GC/MS) was employed for analysis of urine metabolites in 15 renal allograft recipients with acute rejection and 15 stable renal transplant recipients. Partial least squares (PLS) regression and leave-one-out analyses were performed to ascertain whether the metabolites identified could be exploited to distinguish acute rejection from stable groups as well as their sensitivity and specificity.ResultsOverall, 14 metabolites were significantly altered in the acute rejection group (11 and 3 metabolites displayed higher and lower levels, respectively) relative to the stable transplant group. Data from PLS and leave-one-out analyses revealed that the differential metabolites identified not only distinguished acute rejection from stable transplant recipients but also showed high sensitivity and specificity for diagnosis of renal allograft recipients with acute rejection.ConclusionUrine metabolites identified with GC/MS can effectively distinguish acute rejection from stable transplant recipients, supporting the potential utility of metabolome analysis in non-invasive diagnosis of acute rejection.

Effects of preoperative hepatitis B virus infection, hepatitis C virus infection, and coinfection on the development of new-onset diabetes after kidney transplantation

The effects of preoperative hepatitis B virus (HBV) infection, hepatitis C virus (HCV) infection, and HBV plus HCV coinfection on the development of new‐onset diabetes after transplantation (NODAT) remain unexplored in kidney transplant recipients (KTRs). This study examined the association between preoperative viral status (i.e., HBV, HCV, and HBC + HCV infection) and incident NODAT in a large population of Chinese KTRs.