Delayed ischaemic preconditioning in the presence of galectin-9 protects against renal ischaemic injury through a regulatory T-cell dependent mechanism.

AIM: Renal ischaemia/reperfusion injury (IRI) is a complication of major surgeries. Regulatory T cells (Tregs) can suppress immunologic damage in the renal IR. Previous studies indicated that delayed ischaemic preconditioning (IPC) partially attenuates IR by inducing Treg expansion. Galectin-9 also attenuates inflammation-related organ injury by expanding Tregs, but it was not used in renal IR yet. Our aim was to test whether IPC combined with galectin-9 has an increased renoprotective effect. METHODS: Mice were divided into five treatment groups (n = 6 per group): (i) IR group: renal ischaemia/reperfusion group; (ii) IPC-IR group: IPC followed by renal IR; (iii) IPC-Gal9-IR group: Gal-9 injections during the time between IPC and IR; (iv) IPC-Gal9-PC61-IR group: anti-CD25 antibody administration apart from IPC, Gal-9 and IR; (v) sham-sham group. We assessed the renal function, histopathological scores, and percentages of Tregs and interferon-γ (IFN-γ) cells in peripheral bood, spleen, and kidney and compared these values among the different groups. RESULTS: Serum creatinine measured was significantly lower after IPC and even lower in combination with Gal-9 injection. The histopathological scores for tubulo-interstitial injury were decreased following IPC and markedly lower after the addition of Gal-9. The number of kidney infiltrating neutrophils and IFN-γ secreting CD4+ T cells was diminished in the IPC/Gal9 combination group, while the percentage of Treg cells in the peripheral blood, spleen, and kidney of animals from the IPC-Gal9-IR group was also markedly increased. CONCLUSION: The renoprotective effect of delayed IPC combined with galectin-9 was superior to IPC alone, through a mechanism related to expansion of regulatory T cells.

A novel contrast-induced acute kidney injury model based on the 5/6-nephrectomy rat and nephrotoxicological evaluation of iohexol and iodixanol in vivo.

Contrast-induced acute kidney injury (CI-AKI) is a serious complication in patients after administration of iodinated contrast media. Proper animal models of CI-AKI can help understand the mechanisms involved and prevent the disorder. We used the 5/6-nephrectomized (NE) rat to develop a CI-AKI model and to evaluate differences in the toxic effects on the kidney between iohexol and iodixanol. We found that six weeks after ablative surgery was the preferred time to induce CI-AKI. We compared multiple pretreatment plans and found that dehydration for 48 hours before iodixanol (320, 10 mL/kg) administration was optimal to induce CI-AKI in the 5/6 NE rats. Compared with iodixanol, iohexol induced a significantly greater reduction in renal function, severe renal tissue damage, intrarenal hypoxia, and apoptotic tubular cells. Iohexol and iodixanol resulted in similarly marked increases in levels of inflammation and oxidative stress. In summary, the 5/6 NE rat combined with dehydration for 48 hours is a useful pretreatment to establish a novel and reliable CI-AKI model. Iohexol induced more severe CI-AKI than iodixanol in this model.

Efficacy and safety of induction therapy with alemtuzumab in kidney transplantation: a meta-analysis.

BACKGROUND: Alemtuzumab, a humanized CD52 monoclonal antibody, with its profound lymphocyte depletion property, was expected to be a promising induction therapy agent for kidney transplantation (KTx). However, currently no consensus is available about its efficacy and safety. The aim of this meta-analysis was to make a profound review and an objective appraisal of this issue. METHODS: Relevant papers were searched, essentially in the PubMed database and the Cochrane library. After a thorough review, randomized controlled trials (RCTs) comparing the outcome of KTx using alemtuzumab induction therapy (test group) with a control group were collected according to the inclusion criteria. Data of general characteristic of studies and major outcomes of Ktx were extracted and meta-analyses were performed with RevMan 4.2 software. The odds ratio (OR) with a 95% confidence intervals (CI) was the principle measurement of effect. RESULTS: Five RCTs were included. The chi square test showed no significant between-study heterogeneity, thus fixed effect model was employed. Sub-group analysis with studies including alemtuzumab induction followed by a tacrolimus-based immunosuppressive regimen showed that the acute rejection rate (ARR) was lower relative to the control (OR = 0.59, 95% CI 0.34 - 1.01, P = 0.05). However, meta-analysis with all included studies revealed that neither ARR nor patient/graft survival rates differ significantly between the test and the control group, but the cytomegalovirus (CMV) infection rate was higher in the test group (OR 2.50, 95% CI 1.22 - 5.12, P = 0.01). A great number of the test group recipients safely remained on a regimen that was steroid-free and with a reduced dose of conventional immunosuppressive drugs. CONCLUSIONS: Alemtuzumab induction therapy for KTx was an effective and safe protocol in the tested follow-up period. Steroid avoidance and a dose reduction of conventional immunosuppressive drugs after alemtuzumab induction therapy may have clinical importance. However, high quality RCTs with larger population and longer follow-up are needed for a more accurate and objective appraisal of this novel protocol.

PI-3 kinase pathway can mediate the effect of TGF-beta1 in inducing the expression of SHARP-2 in LLC-PK1 cells.

We aim to investigate the effect of transforming growth factor (TGF)-beta1 on the expression of enhancer of split- and hairy-related protein-2 (SHARP-2) messenger RNA (mRNA) and its signaling pathway. In this study, several cell lines including LLC-PK1 (a porcine kidney tubular epithelial cell line), MDCK (Madin-Darby canine kidney) and CTLL-2 (cytotoxic T-lymphocyte line) were treated with recombinant human TGF-beta1, and a series of experiments were carried out, involving Northern blot analysis of total RNA from these cells. Further, several specific chemical inhibitors were applied before TGF-beta1 treatment to probe the signaling pathway. The results showed that TGF-beta1 can significantly up-regulate SHARP-2 mRNA expression in the LLC-PK1 cell line. The peak level of induction was found 2 h after TGF-beta1 stimulation. While one phosphoinositide 3-kinases (PI-3) kinase inhibitor, LY294002, completely blocked the effect of TGF-beta1 on SHARP-2 mRNA expression in LLC-PK1 cells at a low concentration, other inhibitors, including PD98059, staurosporine, AG490, wortmannin, okadaic acid and rapamycin, had no effect. The effect of LY294002 was dose-dependent. We conclude that, in LLC-PK1 cells at least, TGF-beta1 can effectively induce the SHARP-2 mRNA expression and that the PI-3 kinase pathway can mediate this effect.