Research progress of sepsis-associated acute kidney injury based on Gut-Kidney axis / 中华危重病急救医学

Sepsis-associated acute kidney injury (SA-AKI), as a common renal dysfunction in sepsis, has become one of the major diseases threatening human health with increasing morbidity and mortality. Based on the theory of "gut-kidney axis", the intestine and kidney have a two-way synergistic relationship in sepsis. Intestinal flora imbalance, endogenous metabolite imbalance, and impaired endothelial barrier integrity are involved in renal injury, and the increase of renal inflammatory mediators interferes with the composition of intestinal microorganisms. Therefore, understanding the intestinal-renal crosstalk mechanism of SA-AKI will help to provide a potential basis for new treatment strategies for SA-AKI.

Effects of mesencephalic astrocyte-derived neurotrophic factor on sepsis-associated acute kidney injury / 世界急诊医学杂志（英文）

@#BACKGROUND: To determine the protective role of mesencephalic astrocyte-derived neurotrophic factor (MANF) in regulating sepsis-associated acute kidney injury (S-AKI). METHODS: A total of 96 mice were randomly divided into the control group, control+MANF group, S-AKI group, and S-AKI+MANF group. The S-AKI model was established by injecting lipopolysaccharide (LPS) at 10 mg/kg intraperitoneally. MANF (200 μg/kg) was administered to the control+MANF and S-AKI+MANF groups. An equal dose of normal saline was administered daily intraperitoneally in the control and S-AKI groups. Serum and kidney tissue samples were obtained for biochemical analysis. Western blotting was used to detect the protein expression of MANF in the kidney, and enzyme-linked immunosorbent assay (ELISA) was used to determine expression of MANF in the serum, pro-inflammatory cytokines (tumor necrosis factor-α [TNF-α] and interleukin-6 [IL-6]). Serum creatinine (SCr), and blood urea nitrogen (BUN) were examined using an automatic biochemical analyzer. In addition, the kidney tissue was observed for pathological changes by hematoxylin-eosin staining. The comparison between two groups was performed by unpaired Student’s t-test, and statistics among multiple groups were carried out using Tukey’s post hoc test following one-way analysis of variance (ANOVA). A P-value <0.05 was considered statistically significant. RESULTS: At the early stage of S-AKI, MANF in the kidney tissue was up-regulated, but with the development of the disease, it was down-regulated. Renal function was worsened in the S-AKI group, and TNF-α and IL-6 were elevated. The administration of MANF significantly alleviated the elevated levels of SCr and BUN and inhibited the expression of TNF-α and IL-6 in the kidney. The pathological changes were more extensive in the S-AKI group than in the S-AKI+MANF group. CONCLUSION: MANF treatment may significantly alleviate renal injury, reduce the inflammatory response, and alleviate or reverse kidney tissue damage. MANF may have a protective effect on S-AKI, suggesting a potential treatment for S-AKI.

Transcriptome changes upon Toll-like receptor 9 pathway activation in primary renal tubular epithelial cells / 中华危重病急救医学

Objective:To explore the effect of Toll-like receptor 9 (TLR9) signaling pathway activation on the transcriptome in the renal tubular cells.Methods:Mouse primary renal tubular epithelial cells were extracted and cultured. When the degree of cell fusion reached 80%, they were divided into two groups, which were added with 10 μL phosphate buffered saline (PBS, PBS control group) and TLR9 activator cytosine phosphate guanidine oligodeoxynucleotide (CpG-ODN) with a final concentration of 5 μmol/L (CpG-ODN treatment group). The RNA sequencing was performed on the Illumina platform after extraction. DEGseq software was used to analyze the differential expression of genes between the two groups. Goatools and KOBAS online software were used to analyze the differential genes involved signal pathways. Homer software was used to predict transcription factors.Results:Compared with the PBS control group, there were a total of 584 differentially expressed genes in the CpG-ODN treatment group, of which 102 were up-regulated and 482 were down-regulated. The most significantly enriched gene ontology (GO) terms of differentially expressed genes included response to interferon-β, defense response to virus and other inflammatory pathway. The most significantly enriched Kyoto Encyclopedia of Genes and Genomes (KEGG) signaling pathways included 2'-5'-oligoadenylate synthase activity, regulation of ribonuclease activity, negative regulation of virus life cycle, cellular response to interferon-βand defense response to protozoan. The results of transcription factor prediction showed that interferon regulatory factor 3 (IRF3) was the most significantly enriched transcription factor in the promoter sequence of differential genes; the most significant transcription factor downstream of TLR9 was IRF3, and other predicted transcription factors such as transcription factor 21 (TCF21), zinc finger protein 135 (ZNF135), and PR domain containing 4 (PRDM4) might be new candidates for TLR9 signaling pathway.Conclusion:CpG-ODN activates TLR9 signaling pathway, and primary renal tubular epithelial cells can directly respond to CpG-ODN stimulation and undergo transcriptome changes, which provides a basis for further research on the molecular mechanism of TLR9 pathway in sepsis induced acute kidney injury.

Scutellarin alleviates lipopolysaccharide-induced renal injury via mediating cysteine-rich protein 61-connective tissue growth factor-nephroblastoma overexpressed gene 1 expression to inhibit nuclear factor-κB signaling pathway / 中华危重病急救医学

Objective:To explore the protective effect and mechanism of scutellarin (Scu) on sepsis associated-acute kidney injury (SA-AKI).Methods:① In vivo experiment: 36 male C57BL/6 mice were divided into normal saline (NS) control group, lipopolysaccharide (LPS) induced SA-AKI model group (LPS group), 20 mg/kg Scu control group (Scu 20 control group), and 5, 10, 20 mg/kg Scu pretreatment groups by random number table with 6 mice in each group. The SA-AKI model was reproduced by intraperitoneal injection of 10 mg/kg LPS. The NS control group was injected with NS intraperitoneally. The Scu pretreatment groups were intraperitoneally injected with different doses of Scu every day before LPS injection for 1 week. Scu 20 control group was injected with 20 mg/kg Scu for 1 week. After 24 hours of LPS treatment, mice in each group were sacrificed, kidney tissues were collected, and kidney injury was detected by hematoxylin-eosin (HE) staining. Western blotting was used to detect the protein expression levels of nuclear factor-κB (NF-κB) signaling pathway related molecules, apoptosis-related proteins and cysteine-rich protein 61-connective tissue growth factor-nephroblastoma overexpressed gene 1 (CCN1). ② In vitro experiment: human renal tubular epithelial cell line HK-2 was cultured in vitro and used for experiment when the cells fused to 80%. In the cells without LPS treatment and after 100 g/L LPS treatment, pcDNA3.1-CCN1 and small interfering RNA (siRNA) CCN1 sequence were transfected to overexpress and inhibit CCN1 expression, respectively, to observe whether CCN1 was involved in NF-κB signaling pathway activation and apoptosis. In addition, 100g/L LPS and 20 μmol/L Scu were added into HK-2 cells transfected with and without CCN1 siRNA to investigate the mechanism of protective effect of Scu on LPS-induced HK-2 cells injury. Results:① The results of in vivo experiment: the renal function of SA-AKI mice induced by LPS was significantly decreased, and had kidney histological damage and severely damaged renal tubules. Scu could alleviate renal function and histological damage in a dose-dependent manner. Western blotting results showed Scu could reduce the protein expression of NF-κB signaling pathway related molecules and CCN1 in the renal tissue, and had a significant alleviating effect on apoptosis, indicating that CCN1 was involved in NF-κB signaling pathway activation and apoptosis. ② The results of in vitro experiment: in HK-2 cells not treated with LPS, CCN1 overexpression had no effect on apoptosis related protein and pro-inflammatory factors of NF-κB signaling pathway. In HK-2 cells treated with LPS, overexpression of CCN1 significantly inhibited the mRNA expressions of interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α) and monocyte chemoattractant protein-1 (MCP-1), with significant differences as compared with cells stimulated only by LPS [IL-1β mRNA (2 -ΔΔCT): 3.20±0.57 vs. 4.88±0.69, TNF-α mRNA (2 -ΔΔCT): 2.99±0.44 vs. 5.00±0.81, MCP-1 mRNA (2 -ΔΔCT): 2.81±0.50 vs. 5.41±0.75, all P < 0.05], and the apoptosis-related protein was significantly down-regulated. However, when siRNA was used to inhibit the expression of CCN1, the mRNA expressions of pro-inflammatory factors were significantly increased as compared with cells stimulated only by LPS [IL-1β mRNA (2 -ΔΔCT): 6.01±1.13 vs. 4.88±0.69, TNF-α mRNA (2 -ΔΔCT): 5.15±0.86 vs. 5.00±0.81, all P < 0.05], and apoptosis-related protein was significantly up-regulated. In the LPS-induced HK-2 cells, the mRNA expressions of pro-inflammatory factors were significantly down-regulated after Scu treatment as compared with cells stimulated only by LPS [IL-1β mRNA (2 -ΔΔCT) : 2.55±0.50 vs. 6.15±1.04, TNF-α mRNA (2 -ΔΔCT): 2.58±0.40 vs. 3.95±0.52, MCP-1 mRNA (2 -ΔΔCT): 2.64±0.44 vs. 6.21±0.96, all P < 0.05], and apoptosis-related protein was also significantly reduced. When the expression of CCN1 was inhibited by siRNA, the protective effect of Scu on cells was weakened, which showed that the mRNA expressions of pro-inflammatory factors in cells was significantly up-regulated compared with the cells without inhibition of CCN1 expression [IL-1β mRNA (2 -ΔΔCT): 5.34±0.76 vs. 2.55±0.50, TNF-α mRNA (2 -ΔΔCT): 3.66±0.54 vs. 2.58±0.40, MCP-1 mRNA (2 -ΔΔCT): 5.15±0.79 vs. 2.64±0.44, all P < 0.05], and the expression of apoptosis related protein was also significantly up-regulated. Conclusions:Scu could protect the renal function in SA-AKI mice, and the protective effect is associated with NF-κB signaling pathway and CCN1. Thus, Scu could alleviate LPS-induced kidney injury by regulating the NF-κB signaling pathway.

Advances on machine learning applications in sepsis associated-acute kidney injury / 中华危重病急救医学

Sepsis associated-acute kidney injury (SA-AKI) is a common complication of sepsis, which has a high incidence and is closely related to a poor prognosis. However, delayed diagnosis and non-specific treatments make it difficult to systematically manage SA-AKI. Based on massive clinical data, machine learning could build prediction models, which provide alarms and suggestions for the clinical decision support system. Although there are still many challenges such as poor interpretability, it has shown clinical application value in SA-SKI risk prediction, imaging diagnosis, subtype identification, prognosis assessment, and so on. Based on a brief introduction of machine learning, this article reviews the application, limitations, and future directions of machine learning in the diagnosis and treatment of SA-AKI, and explores the possibility of machine learning in the medical field, in order to promote the development of precision medicine and intelligent medicine.

Sepsis-associated acute kidney injury: mechanisms and continuous renal replacement therapy / 中国小儿急救医学

Sepsis is frequently complicated by multiple organ dysfunctional syndrome, and particularly by acute kidney injury.Sepsis-associated acute kidney injury(SAKI)is associated with high risk of hospital mortality and worse disability.The pathophysiological mechanisms for SAKI are still not fully defined.More importance is now increasingly attributed to immunologic and inflammatory mechanisms, along with the activation of the coagulation cascade, triggering adaptive responses of apoptotic cell death and sublethal injury of tubular epithelial cells (TECs)that amplify and potentiate microvascular and endothelial damage.Continuous renal replacement therapy(CRRT)can remove toxins and inflammatory factors, maintain hemodynamics, moderate fluid imbalance.The mode include continuous veno-venous hemofiltration, high volume hemofiltration, continuous veno-venous hemodiafiltration, and etc.But the CRRT timing and dosage need further inquiry.