Xuzhong Liu

Association between NFKB1 −94ins/del ATTG Promoter Polymorphism and Cancer Susceptibility: An Updated Meta-Analysis

Nuclear factor-κB is associated with the pathogenesis of numerous malignancies, and the functional polymorphism −94ins/del ATTG (rs28362491) in the human NFKB1 gene is associated with cancer risk. Previous studies on the association between the −94ins/del ATTG polymorphism and cancer risk reported conflicting results. To clarify this relationship, we performed a meta-analysis of 21 case-control studies involving 6127 cases and 9238 controls. We used pooled odds ratios (ORs) with their 95% confidence intervals (95% CIs) to assess the association. We found that the NFKB1 promoter −94ins/del ATTG polymorphism was significantly associated with cancer risk in four genetic models (ins/ins versus del/del, OR = 1.47, 95% CI = 1.11–1.93; dominant model, OR = 1.26, 95% CI = 1.03–1.53; recessive model, OR = 1.26, 95% CI = 1.05–1.51; ins allele versus del allele, OR = 1.19, 95% CI = 1.05–1.35). Stratified analyses revealed a significant association between the polymorphism and ovarian, oral, and prostate cancers. Similar results were determined in an Asian population and not in a Caucasian population. Thus, our results suggested that the polymorphism can contribute to cancer risk. Moreover, the polymorphism can exert race- and cancer-specific effects on cancer risk. Further large-scale and functional studies are necessary to elucidate this possible effect.

Serum MicroRNA-99a Helps Detect Acute Rejection in Renal Transplantation.

BACKGROUND MicroRNAs (miRNAs) are short, single-stranded, non-coding RNAs, and they are becoming increasingly known as potential biomarkers for a variety of pathologies. However, the significance of circulating miRNAs in renal transplantation patients needs further studies. MATERIALS AND METHODS An miRNA array was used to profile the serum miRNAs of stable transplantation patients and transplantation patients with acute rejection (AR). We performed quantitative real-time polymerase chain reaction with the serum samples from 12 patients with AR, 11 control transplantation patients without rejection, and 15 transplantation patients with delayed graft function (DGF) for validation. Receiver operator characteristic analysis was used to assess the diagnostic capacity of serum miRNA. RESULTS The miR-99a, miR-100, miR-151a, let-7a, let-7c, and let-7f were deregulated in the serum of the patients with AR. In the validation set, only miR-99a and miR-100 were upregulated in the AR group. We further evaluated the expression levels of miR-99a and miR-100 in the DGF group. Only miR-99a was observed with the potent diagnostic value in discriminating AR patients from stable patients (area under the curve [AUC] = 0.750, 95% confidence interval [CI] = 0.529-0.971, P = .042) and DGF patients (AUC = 0.811, 95% CI = 0.600-1.000, P = .006). CONCLUSION Serum miR-99a may serve as a biomarker of AR in renal transplantation patients. Further studies are required to confirm the results.

Advanced glycation end products accelerate arteriosclerosis after renal transplantation through the AGE/RAGE/ILK pathway

BACKGROUND The effects of advanced glycation end products (AGEs) on arteriosclerosis (AS) after kidney transplantation and the molecular mechanisms involved remain unclear. METHODS Samples were collected from 30 healthy volunteers and 30 renal transplant recipients (RTRs) to determine the levels of AGEs and to observe both histological changes and α-smooth muscle actin (α-SMA) and osteopontin (OPN) expression. Furthermore, we analyzed α-SMA, OPN and integrin-linked kinase (ILK) in rat vascular smooth muscle cells (VSMCs) that were treated with AGEs and in ILK plasmid transfected rat VSMCs treated with AGEs. Finally, we measured the expression of ILK and the receptor for advanced glycation end (RAGE) products in rat VSMCs treated with AGEs and an anti-RAGE antibody. RESULTS Significant differences in the histological changes, serum AGEs, and expression of α-SMA and OPN in arterial walls were noted between healthy volunteers and RTRs. Significant OPN and ILK overexpression and reduced α-SMA expression were detected in a time-dependent manner in rat VSMCs after treatment with AGEs. Similar outcomes were observed regarding the overexpression of ILK, and these results could be prevented via RAGE inhibition. CONCLUSIONS AGEs may play a critical role in the formation and progression of AS after renal transplantation by inducing VSMCs-to-osteoblast trans-differentiation through the AGE/RAGE/ILK pathway.

Role of endothelial-to-mesenchymal transition induced by TGF-β1 in transplant kidney interstitial fibrosis

Chronic allograft dysfunction (CAD) induced by kidney interstitial fibrosis is the main cause of allograft failure in kidney transplantation. Endothelial‐to‐mesenchymal transition (EndMT) may play an important role in kidney fibrosis. We, therefore, undertook this study to characterize the functions and potential mechanism of EndMT in transplant kidney interstitial fibrosis. Proteins and mRNAs associated with EndMT were examined in human umbilical vein endothelial cells (HUVECs) treated with transforming growth factor‐beta1 (TGF‐β1) at different doses or at different intervals with western blotting, qRT‐PCR and ELISA assays. Cell motility and migration were evaluated with motility and migration assays. The mechanism of EndMT induced by TGF‐β1 was determined by western blotting analysis of factors involved in various canonical and non‐canonical pathways. In addition, human kidney tissues from control and CAD group were also examined for these proteins by HE, Massons trichrome, immunohistochemical, indirect immunofluorescence double staining and western blotting assays. TGF‐β1 significantly promoted the development of EndMT in a time‐dependent and dose‐dependent manner and promoted the motility and migration ability of HUVECs. The TGF‐β/Smad and Akt/mTOR/p70S6K signalling pathways were found to be associated with the pathogenesis of EndMT induced by TGF‐β1, which was also proven in vivo by the analysis of specimens from the control and CAD groups. EndMT may promote transplant kidney interstitial fibrosis by targetting the TGF‐β/Smad and Akt/mTOR/p70S6K signalling pathways, and hence, result in the development of CAD in kidney transplant recipients.

Clinical Efficacy and Safety of Pamidronate Therapy on Bone Mass Density in Early Post-Renal Transplant Period: A Meta-Analysis of Randomized Controlled Trials

Introduction The overall effect of pamidronate on bone mass density (BMD) in the early renal transplant period varies considerably among studies. The effects of pamidronate on graft function have not been determined. Materials and Methods A comprehensive search was conducted in PubMed, the Cochrane Central Register of Controlled Trials (CENTRAL) and Embase independently by two authors. Randomized controlled trials of pamidronate evaluating bone loss in the first year of renal transplantation were included. Methods reported in the “Cochrane Handbook for Systematic Reviews of Interventions 5.0.2” were used to evaluate changes of lumbar spine and femoral neck BMD, and serum creatinine, calcium and intact parathyroid hormone (iPTH) levels. Fixed or random effect models were used as appropriate. Results Six randomized trials evaluating 281 patients were identified. One hundred forty-four were treated with pamidronate and 137 were control patients. Administration of pamidronate was associated with significant reduction of bone loss in the lumbar spine, compared to the control group (standardized mean difference (SMD)  = 24.62 [16.25, 32.99]). There was no difference between the pamidronate treated and control femoral neck BMD (SMD  = 3.53 [−1.84, 8.90]). A significant increase in the serum creatinine level of the intervention group was seen, compared to the control group. The serum calcium and iPTH of the pamidronate and control groups were not different after 1 year (serum creatinine: SMD  = −3.101 [−5.33, −0.89]; serum calcium: SMD  = 2.18 [−0.8, 5.16]; serum iPTH: SMD  = 0.06 [−0.19, 0.31]). Heterogeneity was low for serum calcium and iPTH and high for serum creatinine. Conclusions This meta-analysis demonstrated the beneficial clinical efficacy of pamidronate on BMD with no association with any alteration in graft function during the first year of renal transplantation. Significant heterogeneity precludes the conclusion of the relationship between serum creatinine and pamidronate.

Performance of the ImmuKnow Assay in Differentiating Infection and Acute Rejection After Kidney Transplantation: A Meta-Analysis

BACKGROUND The ImmuKnow test is an assay for determining the functional activity of immunocytes, which reflects cell-mediated immune responses in populations undergoing organ transplantation. METHODS Electronic and manual searches were conducted to identify studies of the ImmuKnow test. After methodological quality assessment and data extraction, the pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), and diagnostic odds ratio (DOR) were assessed, and summary receiver operating characteristic analysis was performed systematically. The extent of heterogeneity was explored. RESULTS Six studies were identified for analysis. The pooled sensitivity, specificity, PLR, NLR, and DOR of ImmuKnow for predicting the risk of infection were 0.51 (95% confidence interval [CI], 0.45-0.57), 0.75 (95% CI, 0.71-0.78), 1.97 (95% CI, 0.91-4.26), 0.67 (95% CI, 0.38-1.19), and 3.56 (95% CI, 0.80-15.89), respectively. A DOR of 13.81 (95% CI, 0.79-240.44), with a sensitivity of 0.51 (95% CI, 0.40-0.61), a specificity of 0.90 (95% CI, 0.87-0.93), a PLR of 4.45 (95% CI, 0.91-21.74), and an NLR of 0.35 (95% CI, 0.08-1.45), was found in the analysis of the predictive value for acute rejection. The summary receiver operating characteristic curve values for ImmuKnow in distinguishing patients with infections from those with acute rejections were 0.631 ± 0.215 and 0.986 ± 0.015, respectively. CONCLUSIONS Our analysis did not support the use of the ImmuKnow assay to predict or monitor the risks of infection and acute rejection in renal transplant recipients. Further studies are needed to confirm the relationships between the ImmuKnow assay and infection and acute rejection in kidney transplantation.

Alternations of galectin levels after renal transplantation

OBJECTIVES Galectins (gals), a growing family of β-galactoside-binding animal lectins, have been implicated in a variety of biological processes including fibrosis, angiogenesis, and immune activation, all of which are involved in hemodialysis (HD) and renal transplantation (RTx). In this study, we aimed to investigate serum gal levels in HD and RTx recipients. DESIGN AND METHODS 41 normal subjects, 41 RTx recipients and 32 HD patients were recruited for this study. RTx recipients were evaluated before transplantation as well as 3 months afterwards. Serum gals-1, 2, 3, 4, 8, and 9 were measured both at baseline and 3 months later in each group. RESULTS At baseline, there were no differences in gals-1, 2, 3, 4, 8, and 9 between the RTx and HD groups. However, the levels of gals-1, 2, 3, 8, and 9 in the RTx and HD groups were higher than that of normal subjects. In paired analyses, gals-1, 2, and 3 were significantly decreased in RTx patients (P<0.0001) at 3 months, while there was no change in the HD group. However, levels of gals-4, 8, and 9 did not significantly change in either the HD or RTx group. CONCLUSION Gal-1, 2, and 3 levels were high in maintenance HD patients. Kidney transplantation improved gal-1, 2, and 3 levels.

Effect of sirolimus on arteriosclerosis induced by advanced glycation end products via inhibition of the ILK/mTOR pathway in kidney transplantation recipients

ABSTRACT To investigate the effect and related mechanism of sirolimus (SRL) in arteriosclerosis(AS) induced by advanced glycation end products (AGEs) in kidney transplantation recipients (KTRs). Human kidney tissues from KTRs before and after treatment with SRL were assessed by hematoxylin‐eosin and immunohistochemical staining. Rat vascular smooth muscle cells (VSMCs) were treated with AGEs and/or SRL. The expressions of &agr;‐smooth muscle actin (&agr;‐SMA), osteopontin (OPN), actinin‐associated LIM protein (ALP), proliferating cell nuclear antigen (PCNA), integrin‐linked kinase (ILK) and the mTOR signaling pathway proteins were examined using western blot assay. Cytosolic calcium present in VSMCs was also measured by the calcium assay kit and von Kossa staining assay. The expression of &agr;‐SMA was remarkably higher while OPN expression was significantly lower in recipients with AS after they were administered SRL. Rat VSMCs treated with AGEs exhibited significantly lower expression of &agr;‐SMA and overexpression of OPN, ALP and PCNA than the other groups. In contrast, the expression of &agr;‐SMA was significantly higher while the expression of OPN, ALP and PCNA was significantly lower in VSMCs treated with both AGEs and SRL. Moreover, the ILK/mTOR signaling pathway was activated in rat VSMCs treated with AGEs, while treatment with AGEs and SRL led to significant inhibition of the ILK/mTOR signaling pathway. AGEs play a critical role in the development and progression of AS after kidney transplantation, but SRL can reverse these effects and therefore slow down the development of AS through inhibition of the ILK/mTOR signaling pathway.

Transforming Growth Factor-β1 Induces Endothelial-to-Mesenchymal Transition via Akt Signaling Pathway in Renal Transplant Recipients with Chronic Allograft Dysfunction.

BACKGROUND Chronic allograft dysfunction (CAD) is the major cause of chronic loss of allograft in kidney transplant recipients. Kidney interstitial fibrosis is identified to be strongly associated with CAD in kidney transplantation. Recently, endothelial-to-mesenchymal transition (EndMT) has been identified as one of the potential mechanisms in kidney interstitial fibrosis. MATERIAL AND METHODS Kidney tissue samples from 25 renal transplant recipients (RTRs) with CAD and healthy volunteers were collected for HE (hematoxylin-eosin), Masson trichrome, and immunohistochemical staining, and indirect immunofluorescence double-staining assay. Moreover, human umbilical vascular endothelial cells (HUVECs) were cultured and treated with TGF-β1 at different doses or intervals. The protein expressions of α-SMA and CD31 were determined by Western blot assay. Furthermore, potential signaling pathways involved in EndMT induced by TGF-β1were also investigated by Western blotting. RESULTS Typical interstitial fibrosis was observed in transplanted renal tissues from the CAD group. We also found a significant increase of TGF-β1 expression in renal tissues from RTRs with CAD compared with the normal group. Moreover, significant over-expressions of α-SMA, collagen-I, and collagen-III and under-expression of CD31 were detected in kidney specimens of the CAD group. Similar expressive tendencies of α-SMA and CD31 proteins were found in HUVECs treated with TGF-β1 in both time-dependent and dose-dependent manners. The activation of the Akt signaling pathway was found in HUVECs induced by TGF-β1 and selective inhibitors. CONCLUSIONS EndMT was observed in kidney tissues from RTRs with CAD, and TGF-β1 can induce the process of EndMT in both time-dependent and does-dependent manners through the Akt signaling pathway.

Association between Angiotensin I-Converting Enzyme Insertion/Deletion Polymorphism and Prognosis of Kidney Transplantation: A Meta-Analysis

Purpose Angiotensin I-converting enzyme (ACE) is crucial in the renin–angiotensin–aldosterone system. ACE insertion/deletion (I/D) polymorphism is a common genetic variation of this gene and is associated with several disease phenotypes. However, the results of published studies on the influence of this polymorphism on renal transplantation are inconsistent. Therefore, a meta-analysis was performed to evaluate the association between ACE I/D polymorphism and prognosis of kidney transplantation. Methods A meta-analysis was performed based on 21 case–control studies from 12 publications (1497 cases and 2029 controls) and 10 studies with quantitative values from 5 publications (814 patients). Pooled odds ratios (ORs) and weighted mean differences (WMDs) with their corresponding 95% confidence intervals (CIs) were used to estimate associations. Results ACE I/D polymorphism was found to be associated with acute rejection (AR) in genotypes DD+ID versus II (OR = 1.62, 95% CI = 1.14–2.29) and with serum creatinine concentration after renal transplantation in genotypes DD versus ID (WMD = 13.12, 95% CI = 8.09–18.16). Stratified analysis revealed that recipients transplanted within a year had higher serum creatinine concentrations in the DD versus ID model. No significant association was found between hypertension and ACE I/D polymorphism. Conclusion ACE I/D polymorphism is associated with AR and allograft function after kidney transplantation.