Prognostic value of neutrophil-to-lymphocyte ratio dynamics in patients with septic acute kidney injury: a cohort study

BACKGROUND

Neutrophil-to-lymphocyte ratio (NLR) has been suggested to be a prognostic marker for various diseases, but whether NLR dynamics (ΔNLR) is related to mortality and disease severity in patients with septic acute kidney injury (AKI) has not been determined.

METHODS

Between August 2013 and August 2021, septic AKI patients at our center were retrospectively enrolled. ΔNLR was defined as the difference between the NLR at septic AKI diagnosis and at hospital admission. The relationship between the ΔNLR and mortality was evaluated by Kaplan-Meier curves, Cox proportional hazards, and cubic spline analyses. The prediction values were compared by area under the receiver-operating characteristic curve (AUROC), net reclassification improvement (NRI), and integrated discrimination improvement (IDI) analyses.

RESULTS

Of the 413 participants, the mean age was 63 ± 17 years, and 134 were female (32.4%). According to the median value, patients in the high-ΔNLR group had significantly greater 90-d mortality (74.4% vs. 46.6%, p < 0.001). After adjustment for potential confounders, high ΔNLR remained an independent predictor of 90-d mortality (HR = 2.80; 95% CI = 1.74-4.49, p < 0.001). Furthermore, ΔNLR had the highest AUROC for 90-d mortality (0.685) among the various biomarkers and exhibited an improved NRI (0.314) and IDI (0.027) when incorporated with PCT and CRP. For secondary outcomes, patients with high ΔNLR had increased risk of 30-d mortality (p = 0.004), need for renal replacement therapy (p = 0.011), and developing stage-3 AKI (p = 0.040) according to the adjusted models.

CONCLUSIONS

High ΔNLR is independently associated with increased risk of patient mortality and adverse outcomes. ΔNLR might be utilized to facilitate risk stratification and optimize septic AKI management.

Pellino1 orchestrates gut-kidney axis to perpetuate septic acute kidney injury through activation of STING pathway and NLRP3 inflammasome

AIMS

Intestinal barrier dysfunction is the initial and propagable factor of sepsis in which acute kidney injury (AKI) has been considered as a common life-threatening complication. Our recent study identifies the regulatory role of Pellino1 in tubular death under inflammatory conditions in vitro. The objective of our current study is to explore the impact of Pellino1 on gut-kidney axis during septic AKI and uncover the molecular mechanism (s) underlying this process.

MATERIALS AND METHODS

Immunohistochemistry (IHC) was conducted to evaluate Pellino1 and NOD-like receptor thermal protein domain associated protein 3 (NLRP3) levels in renal biopsies from critically ill patients with a clinical diagnosis of sepsis. Functional and mechanistic studies were characterized in septic models of the Peli-knockout (Peli1-/-) mice by histopathological staining, enzyme-linked immunosorbent assay (ELISA), flow cytometry, immunofluorescence, biochemical detection, CRISPR/Cas9-mediated gene editing and intestinal organoid.

KEY FINDINGS

Pellino1, together with NLRP3, are highly expressed in renal biopsies from critically ill patients diagnosed with sepsis and kidney tissues of septic mice. The Peli1-/- mice with sepsis become less prone to develop AKI and have markedly compromised NLRP3 activation in kidney. Loss of Peli1 endows septic mice refractory to intestinal inflammation, barrier permeability and enterocyte apoptosis that requires stimulator of interferons genes (STING) pathway. Administration of STING agonist DMXAA deteriorates AKI and mortality of septic Peli1-/- mice in the presence of kidney-specific NLRP3 reconstitution.

SIGNIFICANCE

Our studies suggest that Pellino1 has a principal role in orchestrating gut homeostasis towards renal pathophysiology, thus providing a potential therapeutic target for septic AKI.

Targeting SLC22A5 fosters mitophagy inhibition-mediated macrophage immunity against septic acute kidney injury upon CD47-SIRPα axis blockade

Efferocytosis of apoptotic neutrophils (PMNs) by macrophages is helpful for inflammation resolution and injury repair, but the role of efferocytosis in intrinsic nature of macrophages during septic acute kidney injury (AKI) remains unknown. Here we report that CD47 and signal regulatory protein alpha (SIRPα)-the anti-efferocytotic 'don't eat me' signals-are highly expressed in peripheral blood mononuclear cells (PBMCs) from patients with septic AKI and kidney samples from mice with polymicrobial sepsis and endotoxin shock. Conditional knockout (CKO) of SIRPA in macrophages ameliorates AKI and systemic inflammation response in septic mice, accompanied by an escalation in mitophagy inhibition of macrophages. Ablation of SIRPA transcriptionally downregulates solute carrier family 22 member 5 (SLC22A5) in the lipopolysaccharide (LPS)-stimulated macrophages that efferocytose apoptotic neutrophils (PMNs). Targeting SLC22A5 renders mitophagy inhibition of macrophages in response to LPS stimuli, improves survival and deters development of septic AKI. Our study supports further clinical investigation of CD47-SIRPα signalling in sepsis and proposes that SLC22A5 might be a promising immunotherapeutic target for septic AKI.

Presepsin is a more useful predictor of septic AKI and ARDS for very-old sepsis patients than for young sepsis patients in ICUs: a pilot study

OBJECTIVE

Sepsis is a syndrome of life-threatening organ dysfunction. This study aimed to determine whether presepsin is a useful predictor of septic acute kidney injury (AKI), acute respiratory distress syndrome (ARDS), disseminated intravascular coagulation (DIC), and shock in very-old sepsis patients aged 75 years in intensive care units (ICUs).

RESULTS

A total of 83 adult patients diagnosed with sepsis were prospectively examined and divided into two groups: those aged 75 years and older (over 75 group) and those aged younger than 75 years (under 75 group). Presepsin values were measured after ICU admission. Inflammation-based prognostic scores were also examined. For category classification, total scores ("inflammation-presepsin scores [iPS]") were calculated. Presepsin values, inflammation-based prognostic scores, and iPS were compared between patients with septic AKI, ARDS, DIC, or shock and those without these disorders in the over 75 and under 75 groups. Areas under the curve of presepsin for predicting septic AKI and ARDS in the over 75 group were both > 0.7, which were significantly higher than those in the under 75 group. In conclusion, presepsin is a more useful predictor of septic AKI and ARDS for very-old sepsis patients (over 75 years) than for younger sepsis patients (under 75 years).

Roles of noncoding RNAs in septic acute kidney injury

Septic acute kidney injury (SAKI) is one of the most common and life-threatening complications of sepsis. Patients with SAKI have increased mortality. However, the underlying pathogenesis is unclear, and the treatment targeting SAKI is unsatisfactory. Thus, identifying optimal biomarkers for SAKI diagnosis and treatment is an urgent requisite. Accumulating evidence indicates that noncoding RNAs (ncRNAs) are involved in the occurrence and progression of SAKI. In the present review, we summarized the studies of ncRNAs in SAKI, including microRNAs (miRNAs), long ncRNAs (lncRNAs), and circular RNAs (circRNAs). The ncRNAs are divided into protective and damage factors according to their role in SAKI, and their expression patterns, functions, and molecular mechanisms were elaborated. Next, we proposed that ncRNAs have the potential to be diagnostic and prognostic biomarkers for SAKI and as new therapeutic targets. This review aimed to provide a comprehensive overview of ncRNAs in SKAI and explored the clinical value of ncRNAs as ideal biomarkers of SAKI.

Embelin attenuates lipopolysaccharide-induced acute kidney injury through the inhibition of M1 macrophage activation and NF-κB signaling in mice

Septic acute kidney injury (AKI) is commonly associated with renal dysfunction and high mortality in patients. Owing to the rapid and violent occurrence of septic AKI with inflammation, there are no effective therapies to clinically treat it. Embelin, a natural product, has a potential regulatory role in immunocytes. However, the role and mechanism of embelin in septic AKI remains unknown. This study aimed to elucidate the role of embelin in macrophage regulation in lipopolysaccharide (LPS)-induced septic AKI. Embelin was intraperitoneally administered to mice after LPS injection. And bone marrow-derived macrophages (BMDMs) were subsequently isolated from the mice to explore the immunomodulatory role of embelin in macrophages. We found that embelin attenuated renal dysfunction and pathological renal damage in the LPS-induced sepsis mouse model. Molecular docking predicted that embelin could bind to phosphorylated NF-κB p65 at the ser536 site. Embelin inhibited the translocation of NF-κB p65 via phosphorylation at ser536 in LPS-induced AKI. It also reduced the secretion of IL-1β and IL-6 and increased the secretion of IL-10 and Arg-1 of BMDMs and mice after LPS stimulation, indicating that embelin suppressed macrophage M1 activation in LPS-induced AKI. Therefore, embelin attenuated LPS-induced septic AKI by suppressing NF-κB p65 at ser536 in activated macrophages. This study preclinically suggests a therapeutic role of embelin in septic AKI.

Neohesperidin dihydrochalbazone protects against septic acute kidney injury in mice

BACKGROUND

Neohesperidin dihydrochalbazone (NHDC) shows a range of pharmacological actions, however, in septic acute kidney injury (AKI), the effect of NHDC is little known.

PURPOSE

To assess the role of NHDC against AKI and the possible mechanisms.

METHODS

In vivo, we used different concentration of NHDC (50, 100, and 200 mg/kg) treated septic AKI model of mice. Moreover, in vitro, in HK-2 cells, a lipopolysaccharide (LPS) induced cell model was treated with 10, 20, and 30 μM NHDC. Next, kidney tissue pathologic change, marker of renal injury, apoptosis, and inflammatory factors were assessed using hematoxylin and eosin staining, enzyme-linked immunosorbent assay, terminal deoxynucleotidyl transferase dUTP nick end labeling, and western blot. HK-2 cell apoptosis and viability were assessed via flow cytometry and cell counting kit-8. In HK-2 cells and tissues, NLRP3, caspase 1, ASC, and P38/ERK 1/2/JNK pathway related protein levels were tested using western blot.

RESULTS

NHDC (100 and 200 mg/kg) significantly attenuated kidney injury in caecal ligation and puncture (CLP)-treated mice. In CLP-treated mice, the level of BUN, Scr, KIM-1, and NAGL was reduced by 100 and 200 mg/kg NHDC. Furthermore, 100 and 200 mg/kg NHDC inhibited inflammation by reducing the production of IL-6, TNF-α, and IL-1β, and inhibited oxidative stress by regulating the change of MDA, SOD, GSH, and CAT. NHDC (100 and 200 mg/kg) inhibited renal cell apoptosis by increasing Bcl2 protein expression and inhibiting Bax and cleaved caspase-3 protein expression. Additionally, NHDC (100 and 200 mg/kg) inhibited the protein levels of phosphorylated (p)-P38, p-JNK, p-ERK 1/2, NLRP3, caspase 1, ASC. In vitro, in LPS-stimulated HK-2 cells, NHDC (20 and 30 μM) increased cell viability, reduced cell apoptosis, restrained inflammation by reducing the content of IL-6, TNF-α, and IL-1β, and inhibited the protein expression of caspase 1, NLRP3, ASC, p-P38, p-JNK, and p-ERK1/2. Importantly, the promotive effect of NHDC on HK-2 cell viability was reversed by DHR (an activator of P38 MAPK signaling pathway), and DHR reversed the inhibitive effects of NHDC on HK-2 cell apoptosis and inflammation.

CONCLUSION

For the first time, NHDC was found to inhibit oxidative stress, inflammation, and apoptosis in AKI model, which was related to the inhibition of P38 MAPK pathways. Our findings provided the theoretical basis for NHDC on the prevention of AKI.

Renal histopathology in critically ill patients with Septic Acute Kidney Injury(S-AKI)

PURPOSE

To describe the kidney histopathology of patients with S-AKI and correlate the histological findings with AKI severity, presence of septic shock, and the degree of multiple organic dysfunction (MOD) using the SOFA score.

MATERIALS AND METHODS

This was a prospective, observational, and analytical study of a cohort of critically ill patients with S-AKI who died from sepsis at the "Hospital Español" intensive care unit (ICU). Kidney necropsies were performed within 2 h after death.

RESULTS

We considered twenty (20) patients, with all of them exhibiting S-AKI stage 3 at the same time. In renal histopathology analysis, nonspecific tubulointerstitial (TI) lesions were found in almost all patients (95%). The more frequently found nonspecific TI lesions involved leukocyte infiltration (85%). Necrotic TI lesions were found in 6 patients (30%), and necrotic tubular cell casts were the most frequent lesions (50% of patients). It was not possible to demonstrate an association between the presence of necrotic TI lesions and factors such as the APACHE II score, the global SOFA score, ICU stays, AKI length and renal replacement therapy (RRT).

CONCLUSIONS

The main histopathological findings in kidney necropsies in patients with S-AKI KDIGO 3, showed nonspecific TI lesions, and TI necrosis was only observed in 30% of the cases; therefore, S-AKI cannot be considered to be synonymous with acute tubular necrosis (ATN).

Interruption of neutrophil extracellular traps formation dictates host defense and tubular HOXA5 stability to augment efficacy of anti-Fn14 therapy against septic AKI

The immunosuppressive, inflammatory microenvironment orchestrated by neutrophil extracellular traps (NETs) plays a principal role in pathogenesis of sepsis. Fibroblast growth factor-inducible molecule 14 (Fn14) has been established as a potential target for septic acute kidney injury (AKI), making further therapeutic benefits from combined NETs and Fn14 blockade possible. Methods: The concurrence of NETs and Fn14 in mice and patients with septic AKI were assessed by immunofluorescence, immunohistochemistry, enzyme-linked immunosorbent assay (ELISA) and in silico studies. Survival, histopathological and biochemical analyses of wild-type and PAD4-deficient CMV-Cre; PAD4 fl/fl mice with septic AKI were applied to evaluate the efficacy of either pharmacological or genetic NETs interruption in combination with Fn14 blockade. Molecular mechanisms underlying such effects were determined by CRISPR technology, fluorescence-activated cell sorter analysis (FACS), cycloheximide (CHX) pulse-chase, luciferase reporter and chromatin immunoprecipitation (ChIP) assay. Results: NETs formation is concurred with Fn14 upregulation in murine AKI models of abdominal, endotoxemic, multidrug-resistant sepsis as well as in serum samples of patients with septic AKI. Pharmacological or genetic interruption of NETs formation synergizes with ITEM-2, a monoclonal antibody (mAb) of Fn14, to prolong mice survival and provide renal protection against abdominal sepsis, the effects that could be abrogated by elimination of macrophages. Interrupting NETs formation predominantly perpetuates infiltration and survival of efferocytic growth arrest-specific protein 6+ (GAS6+) macrophages in combination with ITEM-2 therapy and enhances transcription of tubular cell-intrinsic Fn14 in a DNA methyltransferase 3a (DNMT3a)-independent manner through dismantling the proteasomes-mediated turnover of homeobox protein Hox-A5 (HOXA5) upon abdominal sepsis challenge or LPS stimuli. Pharmacological NETs interruption potentiates the anti-septic AKI efficacy of ITEM-2 in murine models of endotoxemic and multidrug-resistant sepsis. Conclusion: Our preclinical data propose that interrupting NETs formation in combination with Fn14 mAb might be a feasible therapeutic strategy for septic AKI.

Circ_RASGEF1B Promotes LPS-Induced Apoptosis and Inflammatory Response by Targeting MicroRNA-146a-5p/Pdk1 Axis in Septic Acute Kidney Injury Cell Model

BACKGROUND

We intended to investigate the function of circular RNA RasGEF domain family member 1B (circ_RASGEF1B) in lipopolysaccharide (LPS)-induced septic acute kidney injury (AKI) cell model and its associated mechanism.

METHODS

TCMK-1 cells were exposed to 10 μg/mL LPS for 24 h to establish a septic AKI cell model. Mice were intraperitoneally injected with 10 mg/kg LPS to establish a septic AKI mice model. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) and Western blot assay were used to measure RNA and protein expression, respectively. Cell viability and apoptosis were assessed by 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and flow cytometry. Cell inflammatory response was analyzed using enzyme-linked immunosorbent assay. Dual-luciferase reporter assay was conducted to confirm the predicted target relationship between microRNA-146a-5p (miR-146a-5p) and circ_RASGEF1B or pyruvate dehydrogenase kinase 1 (Pdk1).

RESULTS

The circ_RASGEF1B level was upregulated in LPS-induced TCMK-1 cells and septic AKI mice models. LPS exposure reduced cell viability and promoted cell apoptosis and inflammatory response partly by upregulating circ_RASGEF1B. Circ_RASGEF1B bound to miR-146a-5p and miR-146a-5p interference partly overturned circ_RASGEF1B silencing-mediated effects in LPS-induced TCMK-1 cells. Pdk1 was a target of miR-146a-5p, and Pdk1 accumulation partly counteracted miR-146a-5p-induced influences in TCMK-1 cells upon LPS stimulation.

CONCLUSION

Circ_RASGEF1B promoted LPS-induced apoptosis and inflammatory response in renal tubular epithelial cells partly by upregulating Pdk1 via acting as miR-146a-5p sponge.

ROCK1 regulates sepsis-induced acute kidney injury via TLR2-mediated endoplasmic reticulum stress/pyroptosis axis

BACKGROUND

It has been reported that ROCK1 participates in the progression of multiple diseases, including septic intestinal barrier, cardiac dysfunction and acute lung injury. However, its regulatory role and specific mechanism in sepsis-induced acute kidney injury (AKI) remain unclear.

METHODS

Cecal ligation puncture (CLP) was conducted to establish sepsis mouse model, and in vitro model was achieved by lipopolysaccharide (LPS) stimulation. Genes expression was evaluated by qRT-PCR, western blot or ELISA was conducted to assess the levels of proteins. Hoechst staining was performed to evaluate cell pyroptosis. LDH activity assay was detected to assess cytotoxicity. Immunohistochemistry was conducted to detect Ly-6G expression and neutrophils distribution in kidney tissues of mice. H&E and TUNEL staining were carried to evaluate kidney injury of mice.

RESULTS

Our findings illuminated that ROCK1 was highly expressed in sepsis-induced AKI, and ROCK1 knockdown inhibited NLRP3-mediated cell pyroptosis in LPS-induced HK-2 cells. Moreover, ROCK1 modulated HK-2 cell pyroptosis by regulating endoplasmic reticulum stress (ERS). TLR2 inhibitor could suppress ERS mediated cell pyroptosis under LPS treatment. Further, TLR2 activator partially reversed the effects of ROCK1 inhibition on ERS mediated pyroptosis in LPS-treated HK-2 cells and CLP mice.

CONCLUSION

In conclusion, ROCK1 may regulate sepsis-induced AKI via TLR2-mediated ERS/pyroptosis axis. Our data demonstrated the role and underlying mechanism of ROCK1 in septic AKI, providing theoretical basis for sepsis-induced AKI treatment.

Redox DAPK1 destabilizes Pellino1 to govern inflammation-coupling tubular damage during septic AKI

Tubular damage initiated by inflammatory response and ischemic/hypoxic stress is a hallmark of septic acute kidney injury (AKI), albeit the molecular mechanism coupling the two events remains unclear. We investigated the intrinsic nature of tubular damage with respect to inflammatory/hypoxic stress during septic AKI.

Methods: The apoptotic response of tubular cells to LPS stimuli was analyzed before and after hypoxia exposure. Cellular ubiquitination, co-immunoprecipitation, GST-pulldown, in vitro protein kinase assay, immunofluorescence and CRISPR technology were adopted to determine the molecular mechanism underlying this process. In vivo characterization was performed in wild-type and DAPK1^-/- mice models of cecal ligation and puncture (CLP).

Results: We found that the MyD88-dependent inflammatory response couples to tubular damage during LPS stimuli under hypoxia in a Fn14/SCF^Fbxw7α-dispensable manner via recruitment of caspase-8 with TRIF-RIP1 signalosome mediated by DAPK1, which directly binds to and phosphorylates Pellino1 at Ser39, leading to Pellino1 poly-ubiquitination and turnover. Either pharmacological deactivation or genetic ablation of DAPK1 makes tubular cells refractory to the LPS-induced damage in the context of hypoxia, while kinase activity of DAPK1 is essential for ruin execution. Targeting DAPK1 effectively protects mice against septic AKI and potentiates the efficacy of a MyD88 homodimerization inhibitor, ST2825.

Conclusion: Our findings provide a rationale for the mechanism whereby inflammation intersects with hypoxic tubular damage during septic AKI through a previously unappreciated role of DAPK1-inducible Ser39 phosphorylation in Pellino1 turnover and underscore that combined targeting DAPK1 and MyD88 might be a feasible strategy for septic AKI management.

Effects of prostaglandin E combined with continuous renal replacement therapy on septic acute kidney injury

BACKGROUND

The effects of prostaglandin E (PGE) combined with continuous renal replacement therapy (CRRT) on renal function and inflammatory responses in patients with septic acute kidney injury (SAKI) remain unclear.

AIM

To investigate the effects of PGE combined with CRRT on urinary augmenter of liver regeneration (ALR), urinary Na+/H+ exchanger 3 (NHE3), and serum inflammatory cytokines in patients with SAKI.

METHODS

The clinical data of 114 patients with SAKI admitted to Yichang Second People's Hospital from May 2017 to January 2019 were collected. Fifty-three cases treated by CRRT alone were included in a control group, while the other 61 cases treated with PGE combined with CRRT were included in an experimental group. Their urinary ALR, urinary NHE3, serum inflammatory cytokines, renal function indices, and immune function indices were detected. Changes in disease recovery and the incidence of adverse reactions were observed. The 28-d survival curve was plotted.

RESULTS

Before treatment, urinary ALR, urinary NHE3, blood urea nitrogen (BUN), serum creatinine (SCr), CD3+ T lymphocytes, CD4+ T lymphocytes, and CD4+/CD8+ T lymphocyte ratio in the control and experimental groups were approximately the same. After treatment, urinary ALR and NHE3 decreased, while BUN, SCr, CD3+ T lymphocytes, CD4+ T lymphocytes, and CD4+/CD8+ T lymphocyte ratio increased in all subjects. Urinary ALR, urinary NHE3, BUN, and SCr in the experimental group were significantly lower than those in the control group, while CD3+ T lymphocytes, CD4+ T lymphocytes, and CD4+/CD8+ T lymphocyte ratio were significantly higher than those in the control group (P < 0.05). After treatment, the levels of tumor necrosis factor-α, interleukin-18, and high sensitivity C-reactive protein in the experimental group were significantly lower than those in the control group (P < 0.05). The time for urine volume recovery and intensive care unit treatment in the experimental group was significantly shorter than that in the control group (P < 0.05), although there was no statistically significant difference in hospital stays between the two groups. The total incidence of adverse reactions did not differ statistically between the two groups. The 28-d survival rate in the experimental group (80.33%) was significantly higher than that in the control group (66.04%).

CONCLUSION

PGE combined with CRRT is clinically effective for treating SAKI, and the combination therapy can significantly improve renal function and reduce inflammatory responses.

Disturbance of mitochondrial dynamics and mitophagy in sepsis-induced acute kidney injury

AIMS

The renal tubule cells require a large number of mitochondria to supply ATP due to their high-energy demand during reabsorption and secretion against chemical gradients and result in mitochondria susceptible to disorder and injury during stress conditions. Injured mitochondria are eventually degraded by mitophagy, and disturbances in mitophagy are associated with the pathogenesis of acute kidney injury (AKI) such as diabetic nephropathy and glomerulosclerosis. However, whether a disturbance in mitophagy has occurred and the role it plays in (SAKI) is still unclear. Therefore, the aim of this study was to investigate the key features of mitophagy and mitochondrial dynamics in sepsis-induced acute kidney injury (SAKI).

MAIN METHODS

In this study, a murine septic AKI model induced by cecal ligation and puncture (CLP) was built; mitophagy and mitochondrial dynamics were measured in mice kidney in different time point.

KEY FINDINGS

The results showed that mitochondrial dynamics were characterized by fission/fusion aberrant, however more inclined to fission, and mitochondrial associated apoptosis was elevated over-time during SAKI. Furthermore, mitophagy was impaired in the later phase of SAKI, although elevated in early stage of SAKI. The results indicate that the underlying mechanisms of impaired mitophagy may associate with the cleavage of Parkin via caspases activated by NLRP3, at least partly.

SIGNIFICANCE

It is conceivable that this selective autophagic process and quality control machinery was impaired, leading to the accumulation of damaged mitochondria, oxidative stress, and cell death. Therefore, a targeted approach, by enhancing mitophagy during SAKI, may be a promising therapeutic strategy.

MicroRNA-191-5p diminished sepsis-induced acute kidney injury through targeting oxidative stress responsive 1 in rat models

There is no effective treatment for septic acute kidney injury (AKI), which is considered a major public health concern in today’s world. Here, we studied the functions of miR-191-5p in septic AKI. MiR-191-5p mimic or mimic control was injected into rats from caudal vein before cecal ligation and puncture (CLP) surgery. Part of kidney tissues was stained by Hematoxylin and Eosin (H&E) for histological examination. The levels of serum cytokines were evaluated using enzyme-linked immunosorbent assay (ELISA). For cell transfection, renal cells were isolated from the kidneys of CLP rat model injected with mimic control and miR-191-5p mimic. With TargetScan prediction, serine/threonine-protein kinase OSR1 was identified as a target of miR-191-5p. Oxidative stress responsive 1 (OXSR1) overexpression vector was transfected into renal cells. Cell viability and apoptosis rate were determined by Cell Counting Kit-8 (CCK-8) and flow cytometry, respectively. We additionally measured the phosphorylation levels of p38 and p65. We found that the injection of miR-191-5p mimic could observably inhibit renal injury scores, and inhibit inflammatory cytokine productions and apoptotic protein levels in septic rats. After being transfected with OXSR1, the apoptosis rates and expressions of B-cell lymphoma-2 (Bcl-2), down-regulated Bax and Cleaved caspase-3 (C caspase-3) indicated overexpressed OXSR1 contributed to cell apoptosis. The up-regulated protein levels of p-p38 and p-p65 may suggest the involvement of p38 MAPK/NF-κB signaling pathway in the functions of OXSR1. Our results showed that the protective effects of miR-191-5p on kidney tissues of septic rats may rely on the repression of OXSR1.

Procalcitonin and N-Terminal Pro-B-Type Natriuretic Peptide for Prognosis in Septic Acute Kidney Injury Patients Receiving Renal Replacement Therapy

BACKGROUND

Sepsis is a complex clinical syndrome leading to severe sepsis and septic shock. It is very common in the intensive care unit with high mortality. Thus, judging its prognosis is extremely important. Procalcitonin (PCT) and -N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels are commonly elevated in sepsis patients, but only a few are discussed in the septic acute kidney injury patients (AKI) who received renal replacement therapy (RRT). Our study is aimed at investigating the prognostic value of PCT and NT-proBNP in septic AKI patients who received RRT.

METHODS

This was a retrospective study of septic AKI patients who underwent RRT in a Chinese university hospital. All enrolled patients tested PCT and NT-proBNP at RRT initiation. PCT and NT-proBNP levels were compared between the survivors and non-survivors. Receiver operating characteristic (ROC) curves of the 2 biomarkers were performed for predicting in-hospital mortality. According to the median value of PCT (16.2 ng/mL) and NT-proBNP (10,271 pg/mL), patients were divided into 4 groups (low PCT and low NT-proBNP; high PCT and low NT-proBNP; low PCT and high NT-proBNP; high PCT and high NT-proBNP). The Kaplan-Meier survival curves were used to analyze the 28-day survival rate in the 4 groups.

RESULTS

A total of 81 patients were enrolled in the study. Of which, 48 (59.3%) patients died during hospitalization. The median of NT-proBNP in non-survivors was significantly higher than in survivors (p = 0.001), while PCT had no significant difference (p = 0.412). The area under the ROC curve of PCT and NT-proBNP for predicting in-hospital mortality was 0.561 (95% CI 0.426-0.695) and 0.729 (95% CI 0.604-0.854). Kaplan-Meier survival curve analysis showed that increased NT-proBNP level was associated with 28-day mortality while combined with PCT there was no statistical difference in 4 different level groups.

CONCLUSION

NT-proBNP has a certain predictive value for the prognosis in septic AKI patients who received RRT. It seems that the initial PCT value for prognosis is limited. The combination of PCT and -NT-proBNP to evaluate the prognosis in these critically ill patients is currently unclear.

Practice of Extracorporeal Therapies for Septic Acute Kidney Injury Patients in Intensive Care Units in Mainland China

BACKGROUND

Continuous renal replacement therapy (CRRT) and other extracorporeal therapies for acute kidney injury (AKI) and other organ dysfunction syndromes in critically ill patients are common in the intensive care unit (ICU). Many studies have focused on clinical practice for managing these conditions. However, there are few studies that describe the utilization of extracorporeal therapies, especially CRRT, in patients with sepsis-associated AKI.

SUMMARY

Two hundred ICU physicians were included in a survey from February 28, 2017, to March 20, 2017, on the current status of septic AKI and clinical practice in CRRT. According to the responses, 40% of sepsis patients in the ICU had AKI, and 25% required extracorporeal therapies. However, 29% of candidates gave up therapy for medical or nonmedical reasons. Overall survival for sepsis was 60%; among survivors, 80% were dialysis free at discharge. CRRT was the most common modality of extracorporeal therapy in the ICU, and 82% of physicians chose convection as the major clearance mode. The survey showed 30% of physicians saw the removal of inflammatory mediators as the major objective of extracorporeal therapies; however, only 18.5% of physicians considered inflammation as a measure to trigger CRRT. The median treatment duration of CRRT in China was 12 h per day for 5 days. Key Messages: There were some similarities and differences in CRRT practice for septic AKI patients in China and globally. The differences reveal some insights into improving the outcomes of these patients.

Isoliquiritigenin attenuates LPS-induced AKI by suppression of inflammation involving NF-κB pathway

Septic acute kidney injury (AKI) characterized as acute infection and renal inflammation, still lacks of effective therapies. Isoliquiritigenin (ISL) as a small molecular from licorice, is able to inhibit the expression of HMGB1. However, the role and mechanism of ISL in septic AKI has not been investigated. In this study, we used LPS injection to induce murine septic AKI. One hour before LPS injection, 50 mg/kg ISL was once orally given to the mice. For the in vitro study, HK₂ human tubular cells were respectively treated with 50 μM and 100 μM ISL 5 hrs before 2 μg/ml LPS stimulation. Then we observed that ISL ameliorated renal dysfunction and attenuated renal tubular injury. ISL inhibited the phosphorylation of IκB-α and NF-κB p65 after LPS induction both in vivo and in vitro. ISL also inhibited NF-κB p65 translocation from cytoplasm to the nucleus upon LPS stimulation. Further, NF-κB p65 translocation could trigger macrophage polarization, neutrophil activation and pro-inflammatory cytokines secretion in LPS-induced inflammation. These results showed that ISL could alleviate LPS-induced AKI by suppressing NF-κB p65 translocation and inhibiting inflammatory responses, indicating protective effects of ISL in LPS-induced acute renal inflammation. This study might be useful for designing potential clinical trials to prevent and treat sepsis induced AKI in patients with serious illness.

How Does Continuous Renal Replacement Therapy Affect Septic Acute Kidney Injury?

Sepsis is the leading cause of acute kidney injury (AKI) in the intensive care unit. As the most common treatment of septic AKI, it is believed that continuous renal replacement therapy (CRRT) can not only maintain the water balance and excrete the metabolic products but also regulate the inflammation and promote kidney recovery. CRRT can remove the inflammatory cytokines to regulate the metabolic adaption in kidney and restore the kidney recovery to protect the kidney in septic AKI. Second, CRRT can provide extra energy supply in septic AKI to improve the kidney energy balance in septic AKI. Third, the anticoagulant used in CRRT also regulates the inflammation in septic AKI. CRRT is not only a treatment to deal with the water balance and metabolic products, but also a method to regulate the inflammation in septic AKI.

Long non-coding RNA PVT1 promote LPS-induced septic acute kidney injury by regulating TNFα and JNK/NF-κB pathways in HK-2 cells

This study aimed to investigate the effect and underlying mechanism of long non-coding RNA plasmacytoma variant translocation 1 (PVT1) in lipopolysaccharide (LPS)-induced inflammation injury in HK-2 cells. We established LPS-induced septic acute kidney injury (AKI) model in HK-2 cells. LPS-induced HK-2 cells were transfected with pc-PVT1, pc-NC, si-PVT1 or si-NC. Cell viability and apoptosis rate were detected by MTT assay and Annexin V-FITC/PI Apoptosis Detection kit, respectively. The relationships of PVT1 and inflammatory factors were evaluated by RNA Immunoprecipitation (RIP) assay. The levels of inflammatory factors, apoptosis-related proteins and the expressions of proteins related to c-Jun N-terminal kinase (JNK) and nuclear factor-κB (NF-κB) signaling pathway were detected by ELISA or Western blotting. Compared with cells with pc-NC, cell viability was remarkably decreased and cell apoptosis rate was increased in LPS-induced cells with pc-PVT1 (p<0.05). The levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and IL-1β were significantly increased in LPS-induced cells with pc-PVT1 compared with cells with pc-NC (p<0.05). All these changes were reversed in LPS-induced cells with si-PVT1 and si-NC (p<0.05). RTP assay revealed that PVT1 could bind to TNF-α. Furthermore, down-regulated PVT1 remarkably reduced the expressions of p-JNK and p-c-Jun, p-IκBα and p-p65 (p<0.05); while increased expressions of these proteins and inflammatory factors induced by up-regulated PVT1 were reversed by JNK or NF-κB inhibitors. PVT1 may promote inflammatory response by binding to TNF-α and inhibiting JNK/NF-κB signaling pathway in LPS-induced septic AKI cells.

Delta neutrophil index is an independent predictor of mortality in septic acute kidney injury patients treated with continuous renal replacement therapy

Background

Delta neutrophil index (DNI), representing an elevated fraction of circulating immature granulocytes in acute infection, has been reported as a useful marker for predicting mortality in patients with sepsis. The aim of this study was to evaluate the prognostic value of DNI in predicting mortality in septic acute kidney injury (S-AKI) patients treated with continuous renal replacement therapy (CRRT).

Method

This is a retrospective analysis of consecutively CRRT treated patients. We enrolled 286 S-AKI patients who underwent CRRT and divided them into three groups based on the tertiles of DNI at CRRT initiation (high, DNI > 12.0%; intermediate, 3.6–12.0%; low, < 3.6%). Patient survival was estimated with the Kaplan-Meier method and Cox proportional hazards models to determine the effect of DNI on the mortality of S-AKI patients.

Results

Patients in the highest tertile of DNI showed higher Acute Physiology and Chronic Health Evaluation II score (highest tertile, 27.9 ± 7.0; lowest tertile, 24.6 ± 8.3; P = 0.003) and Sequential Organ Failure Assessment score (highest tertile, 14.1 ± 3.0; lowest tertile, 12.1 ± 4.0; P = 0.001). The 28-day mortality rate was significantly higher in the highest tertile group than in the lower two tertile groups (P < 0.001). In the multiple Cox proportional hazard model, DNI was an independent predictor for mortality after adjusting multiple confounding factors (hazard ratio, 1.010; 95% confidence interval, 1.001–1.019; P = 0.036).

Conclusion

This study suggests that DNI is independently associated with mortality of S-AKI patients on CRRT.

A clinical score to predict mortality in septic acute kidney injury patients requiring continuous renal replacement therapy: the HELENICC score

Background

This study aimed to identify predictors of early (7-day) mortality in patients with septic acute kidney injury (AKI) who required continuous renal replacement therapy (CRRT).

Methods

Prospective cohort of 186 septic AKI patients undergoing CRRT at a tertiary hospital, from October 2005 to November 2010.

Results

After multivariate adjustment, five variables were associated to early mortality: norepinephrine utilization, liver failure, medical condition, lactate level, and pre-dialysis creatinine level. These variables were combined in a score, which demonstrated good discrimination, with a C-statistic of 0.82 (95% CI = 0.76–0.88), and good calibration (χ² = 4.3; p = 0.83). SAPS 3, APACHE II and SOFA scores demonstrated poor performance in this population.

Conclusions

The HEpatic failure, LactatE, NorepInephrine, medical Condition, and Creatinine (HELENICC) score outperformed tested generic models. Future studies should further validate this score in different cohorts.

Prevention and treatment of sepsis-induced acute kidney injury: an update

Sepsis-induced acute kidney injury (SAKI) remains an important challenge in critical care medicine. We reviewed current available evidence on prevention and treatment of SAKI with focus on some recent advances and developments. Prevention of SAKI starts with early and ample fluid resuscitation preferentially with crystalloid solutions. Balanced crystalloids have no proven superior benefit. Renal function can be evaluated by measuring lactate clearance rate, renal Doppler, or central venous oxygenation monitoring. Assuring sufficiently high central venous oxygenation most optimally prevents SAKI, especially in the post-operative setting, whereas lactate clearance better assesses mortality risk when SAKI is present. Although the adverse effects of an excessive “kidney afterload” are increasingly recognized, there is actually no consensus regarding an optimal central venous pressure. Noradrenaline is the vasopressor of choice for preventing SAKI. Intra-abdominal hypertension, a potent trigger of AKI in post-operative and trauma patients, should not be neglected in sepsis. Early renal replacement therapy (RRT) is recommended in fluid-overloaded patients’ refractory to diuretics but compelling evidence about its usefulness is still lacking. Continuous RRT (CRRT) is advocated, though not sustained by convincing data, as the preferred modality in hemodynamically unstable SAKI. Diuretics should be avoided in the absence of hypervolemia. Antimicrobial dosing during CRRT needs to be thoroughly reconsidered to assure adequate infection control.