Assessing the predictive value of elevated postoperative syndecan-1 levels for progressive acute kidney injury and kidney replacement therapy necessity in adult cardiac surgery patients.

BACKGROUND: The development of acute kidney injury (AKI) post-cardiac surgery significantly increases patient morbidity and healthcare costs. Prior researches have established Syndecan-1 (SDC-1) as a potential biomarker for endothelial injury and subsequent acute kidney injury development. This study assessed whether postoperative SDC-1 levels could further predict AKI requiring kidney replacement therapy (AKI-KRT) and AKI progression. METHODS: In this prospective study, 122 adult cardiac surgery patients, who underwent valve or coronary artery bypass grafting (CABG) or a combination thereof and developed AKI within 48 h post-operation from May to September 2021, were monitored for the progression to stage 2-3 AKI or the need for KRT. We analyzed the predictive value of postoperative serum SDC-1 levels in relation to multiple endpoints. RESULTS: In the study population, 110 patients (90.2%) underwent cardiopulmonary bypass, of which thirty received CABG or combined surgery. Fifteen patients (12.3%) required KRT, and thirty-eight (31.1%) developed progressive AKI, underscoring the severe AKI incidence. Multivariate logistic regression indicated that elevated SDC-1 levels were independent risk factors for progressive AKI (OR = 1.006) and AKI-KRT (OR = 1.011). The AUROC for SDC-1 levels in predicting AKI-KRT and AKI progression was 0.892 and 0.73, respectively, outperforming the inflammatory cytokines. Linear regression revealed a positive correlation between SDC-1 levels and both hospital (ß = 0.014, p = 0.022) and ICU stays (ß = 0.013, p < 0.001). CONCLUSION: Elevated postoperative SDC-1 levels significantly predict AKI progression and AKI-KRT in patients following cardiac surgery. The study's findings support incorporating SDC-1 level monitoring into post-surgical care to improve early detection and intervention for severe AKI.

Lipoprotein-associated phospholipase A2 predicts cardiovascular death in patients on maintenance hemodialysis: a 7-year prospective cohort study.

BACKGROUND: Cardiovascular diseases (CVD) is the leading cause of death among maintenance hemodialysis patients, with dyslipidemia being a prevalent complication. The paradoxical relationship between cardiovascular outcomes and established lipid risk markers, such as low-density lipoprotein cholesterol (LDL-C), complicates lipid management in this population. This study investigated Lipoprotein-associated phospholipase A2 (Lp-PLA2), an emerging biomarker known for its proinflammatory and proatherogenic properties, as a potential cardiovascular prognostic marker in this cohort. In this context, the association between Lp-PLA2 levels and cardiovascular outcomes was evaluated, with the aim to facilitate more accurate stratification and identification of high-risk individuals. METHODS: From August 2013 to January 2014, 361 hemodialysis patients were prospectively enrolled. Lp-PLA2 activity and laboratory measures at baseline were quantified. Comorbidities and medications were recorded. All patients were followed until the end of April, 2022. The individual and combined effects of Lp-PLA2 activity and LDL-C on patient outcomes were examined. The association between Lp-PLA2 activity and all-cause mortality, cardiovascular mortality, and major adverse cardiovascular events (MACEs) was analyzed. RESULTS: The median Lp-PLA2 activity was 481.2 U/L. In subjects with Lp-PLA2 activity over 481.2 U/L, significantly higher total cholesterol (4.89 vs. 3.98 mmol/L; P < 0.001), LDL-C (3.06 vs. 2.22 mmol/L; P < 0.001), and apolipoprotein B (0.95 vs. 0.75 mmol/L; P < 0.001) were observed. Over a median follow-up of 78.1 months, 182 patients died, with 77 cases identified as cardiovascular death, 88 MACEs happened. Cardiovascular mortality and MACEs, but not all-cause mortality, were significantly increased in the high Lp-PLA2 group. Cox regression analyses showed that high Lp-PLA2 activity was associated with cardiovascular mortality and MACE occurrence. After comprehensive adjustment, high Lp-PLA2 activity was independently associated with cardiovascular mortality(as a dichotomous variable: HR:2.57, 95%CI:1.58,4.18, P < 0.001; as a continuous variable: HR:1.25, 95%CI:1.10,1.41, P = 0.001) and MACEs(as a dichotomous variable: HR:2.17, 95%CI:1.39,3.40, P = 0.001; as a continuous variable: HR:1.20, 95%CI:1.07,1.36, P = 0.002). When participants were grouped by median Lp-PLA2 activity and LDL-C values, those with high Lp-PLA2 and low LDL-C had the highest CV mortality. The addition of Lp-PLA2 significantly improved reclassification (as a dichotomous variable NRI = 42.51%, 95%CI: 5.0%,61.33%; as a continuous variable, NRI = 33.32%, 95% CI: 7.47%,56.21%). CONCLUSIONS: High Lp-PLA2 activity is an independent risk factor for cardiovascular mortality and MACEs occurrence in patients on hemodialysis. The combined measures of Lp-PLA2 and LDL-C help to identify individuals with a higher risk of cardiovascular death.

Emodin Inhibits the Indoxyl Sulfate-Induced trans-Differentiation of Vascular Smooth Muscle Cells through Upregulating Thrombospondin-1.

BACKGROUND: Indoxyl sulfate (IS) is a protein-bound uremic toxin with vascular toxicity. The primary cause of death in uremic patients on maintenance hemodialysis is vascular disease, and it had been reported that vascular smooth muscle cells (VSMCs) trans-differentiation (VT) plays a vital role in the context of vascular diseases, but the underlying mechanisms remain obscure. Thrombospondin-1 (TSP-1) participates in vascular calcification by keeping the balance of extracellular matrix, but its role in IS-induced VT is unclear. METHODS: In this study, clinical specimens, animal models, and in vitro VSMCs were used to investigate the role of TSP-1 in IS induced VT and the potential therapeutic methods. RESULTS: We found that TSP-1 was significantly decreased in arterial samples from uremic patients, animal models, and in VSMCs after IS treatment. Downregulation of TSP-1 sufficiently induced the trans-differentiation genotypes of VSMCs. CONCLUSION: Emodin, the main monomer extracted from rhubarb, could alleviate IS-induced VT in vitro by upregulating TSP-1. Taken together, IS induces VT by downregulating TSP-1. Emodin might be a candidate drug to alleviate VT under IS treatment.

Proteinuria is a risk factor for acute kidney injury after cardiac surgery in patients with stages 3-4 chronic kidney disease: a case control study.

BACKGROUND: Acute kidney injury (AKI) is a common complication after cardiac surgery, and preoperative renal dysfunction is an important risk factor. Proteinuria indicates renal structural damage, but there are few studies on proteinuria and the risk of AKI after cardiac surgery in patients with renal dysfunction. This study aimed to elucidate whether proteinuria can predict AKI after cardiac surgery in patients with renal dysfunction. METHODS: Patients with stages 3-4 chronic kidney disease (CKD) who underwent cardiac surgery were included in this retrospective study. AKI was defined according to the KDIGO criteria. The association between proteinuria and AKI in patients with CKD stages 3-4 was investigated. RESULTS: The incidence of AKI in the entire cohort (n = 1546) was 53.55%. The in-hospital mortality of patients with was higher than patients without AKI (AKI vs. no AKI, 4.7 vs. 0.8%, P < 0.001). Multivariate logistic regression analysis showed that proteinuria was an independent risk factor for AKI (trace to 1+ OR 2.37; 2+ -3+ OR 5.16) and AKI requiring renal replacement therapy (AKI-RRT) (trace to 1+ OR 3.64; 2+-3+ OR 5.71). Mild proteinuria (trace to 1+ OR 2.59) was also an independent risk factor for in-hospital death. In patients with diabetes mellitus, mild proteinuria (OR 1.925), instead of severe proteinuria (2-3+), was a risk factor of AKI in patients with kidney dysfunction and diabetes. CONCLUSIONS: In the population of patients with renal dysfunction, the incidence of AKI was high, which significantly compromised renal and overall prognosis. As a simple and inexpensive routine test, preoperative proteinuria still has value in predicting AKI in patients with impaired renal function.

Effect of angiography timing on acute kidney injury after cardiac surgery in patients with preoperative renal dysfunction.

BACKGROUND: Cardiac surgery-associated acute kidney injury (AKI) is one of the common complications of cardiac surgery. Preoperative angiography helps assess heart disease but may increase the risk of AKI. Although more and more patients with preoperative renal dysfunction can undergo cardiac surgery with the advances in surgical techniques, there is little research on the effect of angiography on postoperative AKI in these patients. This study investigates whether angiography increases the risk of AKI after cardiac surgery in patients with preoperative renal dysfunction (15 ≤ eGFR < 60 ml/min/1.73m2). METHODS: Patients with preoperative renal dysfunction (15 ≤ eGFR < 60 ml/min/1.73m2) who underwent angiography and cardiac surgery successively from January 2015 to December 2020 were retrospectively enrolled in this study. The primary outcome was postoperative AKI, defined as the Kidney Disease: Improving Global Outcomes Definition and Staging (KDIGO) criteria. Univariate analysis and multivariate regression were performed to identify the association between angiography timing and AKI. RESULTS: A total of 888 consecutive eligible patients with preoperative renal dysfunction (15 ≤ eGFR < 60 ml/min/1.73m2) were enrolled in this study. The incidence of AKI was 48.31%. Male (OR = 1.903), the interval between angiography and surgery (0-2d OR = 2.161; 3-6d OR = 3.291), cross-clamp duration (OR = 1.009), were identified as predictors for AKI. The interval between angiography and surgery was also associated with AKI in the patients with 15 ≤ eGFR < 30ml/min/1.73m2 (0-2d OR = 4.826; 3-6d OR = 5.252), 30 ≤ eGFR < 45 ml/min/1.73m2 (0-2d OR = 2.952; 3-6d OR = 3.677), but not associated with AKI in patients with 45 ≤ eGFR < 60 ml/min/1.73m2. CONCLUSIONS: In patients with preoperative renal dysfunction, the interval between angiography and cardiac surgery (0-2d and 3-6d) was associated with AKI. For patients with poorer preoperative renal function, the interval between angiography and cardiac surgery is of great concern.

Depletion of miR-21 in dendritic cells aggravates renal ischemia-reperfusion injury.

Dendritic cells (DCs) play an important role in the pathophysiology of renal ischemia-reperfusion injury (IRI). The mechanisms underlying DCs phenotypic modulation and their function are not fully understood. In this study, we examined the effect of miR-21 on the phenotypic modulation of DCs in vitro and in vivo, and further investigated the impact of miR-21-overexpression DC or miR-21-deficient DC on renal IRI. We found that treatment with hypoxia/reoxygenation (H/R) suppressed miR-21 expression in bone marrow-derived dendritic cells (BMDCs), and significantly increased the percentage of mature DCs (CD11c+ /MHC-II+ /CD80+ ). Using a selection of microRNA mimics, we successfully induced the upregulation of miR-21 in BMDCs, which induced immature DC phenotype and an anti-inflammatory DC response. However, deletion of miR-21 in BMDCs promoted maturation of DCs under H/R. Adoptive transfer of miR-21-overexpression BMDCs could alleviate renal IR-induced pro-inflammatory cytokines production and acute kidney injury (AKI). Mice with miR-21 deficiency in DCs subjected to renal IR showed more severe renal dysfunction and inflammatory response compared with wild-type mice. In addition, chemokine C receptor 7 (CCR7), a surface marker of mature DC, was a target gene of miR-21, and silencing of CCR7 in BMDCs led to reduced mature DCs under H/R. In conclusion, our findings highlight miR-21 as a key regulator of DCs subset phenotype and a potential therapeutic target in renal IRI.

Neutrophil to Lymphocyte Ratio as a Predictor of Long-Term Outcome in Peritoneal Dialysis Patients: A 5-Year Cohort Study.

INTRODUCTION: The mortality of peritoneal dialysis (PD) patients remains high. The neutrophil to lymphocyte ratio (NLR), as an indicator of systemic inflammation, has been considered to be a predictor of cardiovascular and all-cause mortality in hemodialysis patients. The present study aims to investigate the relationship between NLR and long-term outcome in PD patients. MATERIALS AND METHODS: The study included patients who initiated PD for at least 3 months between January 1, 2013, and December 31, 2015. All the patients were followed up until death, cessation of PD, or to the end of the study (June 31, 2018). NLR was calculated as the ratio of neutrophils to lymphocytes. RESULTS: A total of 140 patients were included in this study. The median NLR reported was 2.87. Patients with lower NLR showed a higher survival rate than patients with higher NLR (log rank 6.886, p = 0.009). Furthermore, patients with higher NLR had a significantly higher cardiovascular mortality (log rank 5.221, p = 0.022). Multivariate Cox proportional hazards model showed that older age (HR 1.054, 95% CI 1.017-1.092, p = 0.004), higher Ca × P (HR 1.689, 95% CI 1.131-2.523, p = 0.010), and higher NLR (HR 2.603, 95% CI 1.037-6.535, p = 0.042) were independent predictors of increased all-cause mortality. NLR was also independently associated with cardiovascular mortality (HR 2.886, 95% CI 1.005-8.283, p = 0.039). Higher NLR (HR 2.667, 95% CI 1.333-5.337, p = 0.006), older age (HR 1.028, 95% CI 1.005-1.052, p = 0.016), and history of cardiovascular disease (HR 1.426, 95% CI 1.195-3.927, p = 0.031) were significantly independently associated with poor peritonitis-free survival in this study. CONCLUSIONS: NLR could be a strong predictor of long-term outcome in PD patients.

Murine knockin model for progranulin-deficient frontotemporal dementia with nonsense-mediated mRNA decay.

Frontotemporal dementia (FTD) is the most common neurodegenerative disorder in individuals under age 60 and has no treatment or cure. Because many cases of FTD result from GRN nonsense mutations, an animal model for this type of mutation is highly desirable for understanding pathogenesis and testing therapies. Here, we generated and characterized GrnR493X knockin mice, which model the most common human GRN mutation, a premature stop codon at arginine 493 (R493X). Homozygous GrnR493X mice have markedly reduced Grn mRNA levels, lack detectable progranulin protein, and phenocopy Grn knockout mice, with CNS microgliosis, cytoplasmic TDP-43 accumulation, reduced synaptic density, lipofuscinosis, hyperinflammatory macrophages, excessive grooming behavior, and reduced survival. Inhibition of nonsense-mediated mRNA decay (NMD) by genetic, pharmacological, or antisense oligonucleotide-based approaches showed that NMD contributes to the reduced mRNA levels in GrnR493X mice and cell lines and in fibroblasts from patients containing the GRNR493X mutation. Moreover, the expressed truncated R493X mutant protein was functional in several assays in progranulin-deficient cells. Together, these findings establish a murine model for in vivo testing of NMD inhibition or other therapies as potential approaches for treating progranulin deficiency caused by the R493X mutation.

TGF-ß1 inhibits the autophagy of podocytes by activating mTORC1 in IgA nephropathy.

IgA nephropathy (IgAN) is a mesangial proliferative glomerulonephritis which often shows proteinuria, an indicator for podocyte damage. TGF-ß1 has been known to contribute to podocyte injury by inducing apoptosis, cytoskeleton relocation or cytoskeleton loss. And Decorin, a small proteoglycan known to neutralize TGF-ß1, was reported to induce autophagy in vascular endothelial cells. However, it remains unknown how TGF-ß1 and Decorin can affect podocyte autophagy in mesangial proliferative glomerulonephritis. In this study, we used in vivo and in vitro models to find out the effect of TGF-ß1 and Decorin on podocyte autophagy. P-rpS6 and p-ULK1 were detected by Western blot to show the activation of mTORC1 pathway following TGF-ß1 treatment. Also, we collected serum from IgAN patients and anti-Thy1.1 nephritis, and quantified TGF-ß1 and Decorin using ELISA. Together, we showed that TGF-ß1 could activate mTORC1 and inhibit autophagy, while Decorin has precisely the opposite effect. As the mesangial cells (MCs) proliferate, TGF-ß1 increases and Decorin decreases in the serum of IgAN and anti-Thy1.1 nephritis. This finding deepened our understanding regarding how MC proliferation could finally result in podocyte dysfunction.

Effect of long non-coding RNA growth arrest-specific 5 on apoptosis in renal ischaemia/reperfusion injury.

AIM: Long non-coding RNA (lncRNAs) have been shown to play a critical role in a variety of pathophysiological processes, such as cell proliferation, apoptosis and migration. However, there were few studies addressing the function of lncRNAs in renal ischaemia/reperfusion (I/R) injury. Apoptosis is an important pathogenesis during I/R injury. Here, we identified the effect of hypoxia-responsive lncRNA growth arrest-specific 5 (GAS5) on apoptosis in renal I/R injury. METHODS: Ischaemia/reperfusion injury in mice or hypoxia/re-oxygenation (H/R) in human proximal renal tubular epithelial cells (HK-2) was practiced to induce apoptosis. The kidneys and blood were collected at 24 h after reperfusion. The GAS5 messenger RNA (mRNA) expression and apoptosis-related gene mRNA and protein levels, including p53, cellular inhibitor of apoptosis protein 2 (cIAP2) and thrombospondin-1 (TSP-1), were analysed. GAS5 small-interfering RNA was transfected with H/R induced cells. Over-expression of GAS5 was performed by plasmid transfection. RESULTS: Apoptotic cells significantly increased in I/R-injured kidneys. GAS5 could be up-regulated in kidneys at 24 h after reperfusion and 3 h after re-oxygenation, combined with increased expression of its downstream apoptosis-related proteins p53 and cIAP2. GAS5 small-interfering RNA treatment down-regulated the mRNA and protein levels of p53 and TSP-1, and attenuated apoptosis induced by H/R in HK-2 cells. Conversely, over-expression of GAS5 up-regulated the mRNA and protein levels of p53 and TSP-1, and promoted apoptosis in HK-2 cells. CONCLUSION: Long non-coding RNA GAS5 induced by I/R injury could promote apoptosis in kidney. TSP-1 might be one of the downstream effectors of GAS5, which will be explored in the future.

Evaluation of five different renal recovery definitions for estimation of long-term outcomes of cardiac surgery associated acute kidney injury.

BACKGROUND: The commonly used recommended criteria for renal recovery are not unequivocal. This study compared five different definitions of renal recovery in order to evaluate long-term outcomes of cardiac surgery associated acute kidney injury (CSA-AKI). METHODS: Patients who underwent cardiac surgery between April 2009 and April 2013 were enrolled and divided into acute kidney injury (AKI) and non-AKI groups. The primary endpoint was 3-year major adverse events (MAEs) including death, new dialysis and progressive chronic kidney disease (CKD). We compared five criteria for complete renal recovery: Acute Renal Failure Trial Network (ATN): serum creatinine (SCr) at discharge returned to within baseline SCr + 0.5 mg/dL; Acute Dialysis Quality Initiative (ADQI): returned to within 50% above baseline SCr; Pannu: returned to within 25% above baseline SCr; Kidney Disease: Improving Global Outcomes (KDIGO): eGFR at discharge ≥60 mL/min/1.73 m2; Bucaloiu: returned to ≥90% baseline estimated glomerular filtration rate (eGFR). Multivariate regression analysis was used to compare risk factors for 3-year MAEs. RESULTS: The rate of complete recovery for ATN, ADQI, Pannu, KDIGO and Bucaloiu were 84.60% (n = 1242), 82.49% (n = 1211), 60.49% (n = 888), 68.60% (n = 1007) and 46.32% (n = 680). After adjusting for confounding factors, AKI with complete renal recovery was a risk factor for 3-year MAEs (OR: 1.69, 95% CI: 1.20-2.38, P <  0.05; OR: 1.45, 95% CI: 1.03-2.04, P <  0.05) according to ATN and ADQI criteria, but not for KDIGO, Pannu and Bucaloiu criteria. We found that relative to patients who recovered to within 0% baseline SCr or recovered to ≥100% baseline eGFR, the threshold values at which significant differences in 3-year MAEs were observed were > 30% or > 0.4 mg/dL above baseline SCr or < 70% of baseline eGFR. CONCLUSIONS: ADQI or ATN-equivalent criteria may overestimate the extent of renal recovery, while KDIGO, Pannu and Bucaloiu equivalent criteria may be more appropriate for clinical use. Our analyses revealed that SCr at discharge > 30% or > 0.4 mg/dL of baseline, or eGFR < 70% of baseline led to significant 3-year MAE incidence differences, which may serve as hints for new definitions of renal recovery.

Delayed Ischemic Preconditioning Attenuated Renal Ischemia-Reperfusion Injury by Inhibiting Dendritic Cell Maturation.

BACKGROUND/AIMS: Even though delayed ischemic preconditioning (DIPC) has been reported to produce renal protection, the underlying mechanism remains poorly understood. We reported that a 15-minute renal ischemic preconditioning (IPC) 4 days before subsequent ischemia-reperfusion attenuated renal injury Kidney dendritic cells (DCs) are abundant in the renal tubulointerstitium and, depending on their status, can induce immune activation or tolerance. The aim of the present study was to investigate the role of DCs in IPC of the kidney. METHODS: Mouse kidneys were challenged by transient brief episodes of sublethal ischemia followed by subsequent prolonged ischemia. DC abundance and maturation in the spleen and kidney were measured by flow cytometry and immunohistochemical staining. To confirm the function of mature DCs in the renoprotective effect of IPC on renal ischemia-reperfusion injury the A2 adenosine receptor (A2AR) antagonist SCH58261 was administered to stimulate DC maturation prior to assessment of renal functional and histological injury and the inflammatory reaction. RESULTS: Compared with sham-operated animals, preconditioned mice had a reduced injury with less CD11c+ cells, lower levels of the pro-inflammatory cytokine IL-17 and reduced expression of the mature DC marker CCR7. Preconditioned mice also produced more of the anti-inflammatory cytokine IL-10. Both renal cells and splenocytes from these mice had more DCs (CD45+/CD11c+/F4/80-), but fewer of these DCs were mature (CD45+/CD11c+/ F4/80-/MHC-II+/CD80+) compared with those from sham-treated animals, suggesting that the immunomodulatory effect of renal ischemic preconditioning is both local and systemic. Additionally, injection of the A2AR antagonist SCH58261 reversed IPC-induced inhibition of DC maturation and mitigated the protective effect of preconditioning, suggesting that DC maturation contributes to immune cell-mediated ischemic preconditioning. CONCLUSION: Our results show that DIPC of the kidney provides local and systemic immunosuppression by inhibiting DC maturation and hence mediates a renal protective effect.

Downregulation of the Host Gene jigr1 by miR-92 Is Essential for Neuroblast Self-Renewal in Drosophila.

Intragenic microRNAs (miRNAs), located mostly in the introns of protein-coding genes, are often co-expressed with their host mRNAs. However, their functional interaction in development is largely unknown. Here we show that in Drosophila, miR-92a and miR-92b are embedded in the intron and 3'UTR of jigr1, respectively, and co-expressed with some jigr1 isoforms. miR-92a and miR-92b are highly expressed in neuroblasts of larval brain where Jigr1 expression is low. Genetic deletion of both miR-92a and miR-92b demonstrates an essential cell-autonomous role for these miRNAs in maintaining neuroblast self-renewal through inhibiting premature differentiation. We also show that miR-92a and miR-92b directly target jigr1 in vivo and that some phenotypes due to the absence of these miRNAs are partially rescued by reducing the level of jigr1. These results reveal a novel function of the miR-92 family in Drosophila neuroblasts and provide another example that local negative feedback regulation of host genes by intragenic miRNAs is essential for animal development.

miR-21 contributes to renal protection by targeting prolyl hydroxylase domain protein 2 in delayed ischaemic preconditioning.

AIM: Upregulation of miR-21 in renal ischaemic preconditioning (IPC) was associated with increased hypoxia inducible factor (HIF)-1α expression. Hypoxic induction of HIF-1α is mediated by inhibition of prolyl hydroxylase domain protein 2 (PHD2) .We hypothesized that miR-21 regulated HIF-1α by targeting PHD2 in the renal IPC. METHODS: Luciferase reporter assay examined if miR-21 target the 3'-untranslated region of PHD2. In vitro, human proximal tubular cell line (HK-2) was incubated in hypoxia or hypoxia/ reoxygenation condition. Kidneys of Mice were respectively subjected to ischaemia/reperfusion injury (IRI) and IPC. Locked nucleic acid (LNA) modified anti-miR-21 was used to knockdown miR-21. Serum creatinine and histological changes estimated the renal injury. Levels of HIF-1α, PHD2, VEGF and miR-21 were examined by western blot or real-time PCR. RESULT: miR-21 targeting of PHD2 was confirmed by 3'-untranslated region reporter assay. miR-21 was significantly upregulated by hypoxia/reoxygenation in HK-2 cell, while PHD2 protein level decreased significantly. LNA anti-miR-21 significantly repressed miR-21 levels and increased the abundance of PHD2. In vivo, IPC upregulated miR-21 expression 24 h after the second ischaemia, while PHD2 expression decreased significantly with upregulation of HIF-1α protein and VEGF mRNA. MiR-21 induced by delayed IPC was effectively inhibited by the LNA anti-miR-21. With downregulation of miR-21, the protection of delayed IPC was attenuated and PHD2 protein was increased. Furthermore, upregulation of HIF-1α and VEGF were abolished after the LNA anti-miR-21 treatment. CONCLUSION: miR-21 could protect kidney against IRI via HIF-1α by inhibiting its target PHD2.The study suggested a new relationship between miR-21 and HIF-1α.

Hyperuricemia increases the risk of acute kidney injury: a systematic review and meta-analysis.

BACKGROUND: Mounting evidence indicated that the elevated serum uric acid level was associated with an increased risk of acute kidney injury (AKI). Our goal was to systematically evaluate the correlation of serum uric acid (SUA) level and incidence of AKI by longitudinal cohort studies. METHODS: We searched electronic databases and the reference lists of relevant articles. 18 cohort studies with 75,200 patients were analyzed in this random-effect meta-analysis. Hyperuricemia was defined as SUA levels greater than 360-420 µmol/L (6-7 mg/dl), which was various according to different studies. Data including serum uric acid, serum creatinine, and incidence of AKI and hospital mortality were summarized using random-effects meta-analysis. RESULTS: The hyperuricemia group significantly exerted a higher risk of AKI compared to the controls (odds ratio OR 2.24, 95% CI 1.76-2.86, p < 0.01). Furthermore, there is less difference of the pooled rate of AKI after cardiac surgery between hyperuricemia and control group (34.3% vs 29.7%, OR 1.24, 95% CI 0.96-1.60, p = 0.10), while the rates after PCI were much higher in hyperuricemia group than that in control group (16.0% vs 5.3%, OR 3.24, 95% CI 1.93-5.45, p < 0.01). In addition, there were significant differences in baseline renal function at admission between hyperuricemia and control groups in most of the included studies. The relationship between hyperuricemia and hospital mortality was not significant. The pooled pre-operative SUA levels were higher in AKI group than that in the non-AKI group. CONCLUSIONS: Elevated SUA level showed an increased risk for AKI in patients and measurements of SUA may help identify risks for AKI in these patients.

Protection of remote ischemic preconditioning against acute kidney injury: a systematic review and meta-analysis.

BACKGROUND: Remote ischemic preconditioning (RIPC) is a promising approach to preventing acute kidney injury (AKI), but its efficacy is controversial. METHODS: A systematic review of 30 randomized controlled trials was conducted to investigate the effects of RIPC on the incidence and outcomes of AKI. Random effects model meta-analyses and meta-regressions were used to generate summary estimates and explore sources of heterogeneity. The primary outcome was incidence of AKI and hospital mortality. RESULTS: The total pooled incidence of AKI in the RIPC group was 11.5 %, significantly less than the 23.3 % incidence in the control group (P = 0.009). Subgroup analyses indicated that RIPC significantly reduced the incidence of AKI in the contrast-induced AKI (CI-AKI) subgroup from 13.5 % to 6.5 % (P = 0.000), but not in the ischemia/reperfusion-induced AKI (IR-AKI) subgroup (from 29.5 % to 24.7 %, P = 0.173). Random effects meta-regression indicated that RIPC tended to strengthen its renoprotective effect (q = 3.95, df = 1, P = 0.047) in these trials with a higher percentage of diabetes mellitus. RIPC had no significant effect on the incidence of stages 1-3 AKI or renal replacement therapy, change in serum creatinine and estimated glomerular filtration rate (eGFR), hospital or 30-day mortality, or length of hospital stay. But RIPC significantly increased the minimum eGFR in the IR-AKI subgroup (P = 0.006) compared with the control group. In addition, the length of ICU stay in the RIPC group was significantly shorter than in the control group (2.6 vs 2.0 days, P = 0.003). CONCLUSIONS: We found strong evidence to support the application of RIPC to prevent CI-AKI, but not IR-AKI.

The FTD/ALS-associated RNA-binding protein TDP-43 regulates the robustness of neuronal specification through microRNA-9a in Drosophila.

TDP-43 is an evolutionarily conserved RNA-binding protein currently under intense investigation for its involvement in the molecular pathogenesis of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). TDP-43 is normally localized in the nucleus, but translocated to the cytoplasm in diseased neurons. The endogenous functions of TDP-43 in the nervous system remain poorly understood. Here, we show that the loss of Drosophila TDP-43 (dTDP-43) results in an increased production of sensory bristles and sensory organ precursor (SOP) cells on the notum of some but not all flies. The location of ectopic SOPs varies among mutant flies. The penetrance of this novel phenotype is dependent on the gender and sensitive to environmental influences. A similar SOP phenotype was also observed on the wing and in the embryos. Overexpression of dTDP-43 causes both loss and ectopic production of SOPs. Ectopic expression of ALS-associated mutant human TDP-43 (hTDP-43(M337V) and hTDP-43(Q331K)) produces a less severe SOP phenotype than hTDP-43(WT), indicating a partial loss of function of mutant hTDP-43. In dTDP-43 mutants, miR-9a expression is significantly reduced. Genetic interaction studies further support the notion that dTDP-43 acts through miR-9a to control the precision of SOP specification. These findings reveal a novel role for endogenous TDP-43 in neuronal specification and suggest that the FTD/ALS-associated RNA-binding protein TDP-43 functions to ensure the robustness of genetic control programs.

miR-21 in ischemia/reperfusion injury: a double-edged sword?

MicroRNAs (miRNAs or miRs) are endogenous, small RNA molecules that suppress expression of targeted mRNA. miR-21, one of the most extensively studied miRNAs, is importantly involved in divergent pathophysiological processes relating to ischemia/reperfusion (I/R) injury, such as inflammation and angiogenesis. The role of miR-21 in renal I/R is complex, with both protective and pathological pathways being regulated by miR-21. Preconditioning-induced upregulation of miR-21 contributes to the protection against subsequent renal I/R injury through the targeting of genes such as the proapoptotic gene programmed cell death 4 and interactions between miR-21 and hypoxia-inducible factor. Conversely, long-term elevation of miR-21 may be detrimental to the organ by promoting the development of renal interstitial fibrosis following I/R injury. miR-21 is importantly involved in several pathophysiological processes related to I/R injury including inflammation and angiogenesis as well as the biology of stem cells that could be used to treat I/R injury; however, the effect of miR-21 on these processes in renal I/R injury remains to be studied.

Hsp70 and Hsp90 oppositely regulate TGF-ß signaling through CHIP/Stub1.

Transforming growth factor-ß (TGF-ß) signaling plays an important role in regulation of a wide variety of cellular processes. Canonical TGF-ß signaling is mediated by Smads which were further regulated by several factors. We previously reported that E3 ubiquitin ligase CHIP (carboxyl terminus of Hsc70-interacting protein, also named Stub1) controlled the sensitivity of TGF-ß signaling by modulating the basal level of Smad3 through ubiquitin-mediated degradation. Here, we present evidence that Hsp70 and Hsp90 regulate the complex formation of Smad3/CHIP. Furthermore, we observed that over-expressed Hsp70 or inhibition of Hsp90 by geldanamycin (GA) leads to facilitated CHIP-induced ubiquitination and degradation of Smad3, which finally enhances TGF-ß signaling. In contrast, over-expressed Hsp90 antagonizes CHIP mediated Smad3 ubiquitination and degradation and desensitizes cells in response to TGF-ß signaling. Taken together, our data reveal an opposite role of Hsp70 and Hsp90 in regulating TGF-ß signaling by implicating CHIP-mediated Smad3 ubiquitination and degradation. This study provides a new insight into understanding the regulation of the TGF-ß signaling by chaperones.

Clinicopathological features of kidney injury in patients receiving immune checkpoint inhibitors (ICPi) combined with anti-vascular endothelial growth factor (anti-VEGF) therapy.

BACKGROUND: Immune checkpoint inhibitor (ICPi) combined with anti-vascular endothelial growth factor (VEGF) therapy has increasingly become a promising strategy in various malignancies. However, the combination might be associated with increased risk of nephrotoxicity. METHODS: We retrospectively recruited patients who suffered kidney injury and received renal biopsy after anti-VEGF/ICPi mono- or combination therapy and divided them into three groups: anti-VEGF monotherapy, ICPi monotherapy and combination therapy. Clinical and histopathological features of three groups were analysed. All patients were followed-up for 3 months after biopsy, with or without glucocorticoid treatment, and renal outcome were compared. RESULTS: A total of 46 patients were enrolled. Eighteen patients received anti-VEGF monotherapy, 12 received ICPi monotherapy and 16 received combined treatment of anti-VEGF and ICPi. Proteinuria level of anti-VEGF group, ICPi group and combination group were 4.07±3.17 g/day, 0.60±0.61 g/day and 2.05±2.50 g/day, respectively (p=0.002). The peak serum creatinine level of combination group (1.75±0.77 mg/dL) was also in between ICPi group (2.79±0.90 mg/dL) and anti-VEGF group (1.34±0.60 mg/dL) (p<0.001). Multiple histopathological patterns involving glomerulus, tubulointerstitium and vessel existed in the majority of cases in combination group (68.8%). Renal complete and partial recovery rate of combination therapy were also in between monotherapy (57.1% vs 40.0% in anti-VEGF group, 100.0% in ICPi group, respectively). CONCLUSIONS: Kidney injury in patients treated with combination therapy of ICPi and anti-VEGF shows hybrid pathological patterns and intermediate clinical features compared with monotherapy. Cohorts with larger sample and better design, as well as basic research, are needed to elucidate the mechanism of 'protection' effect of combination anti-cancer therapy to renal function.