The causal effect of triglyceride and high blood pressure on IgA nephropathy: a Mendelian randomization study.

Background: It has been reported that high blood pressure (HBP) and triglyceride (TG) are considered risk factors in immunoglobulin A nephropathy (IgAN). This study aimed to explore the causalities between HBP and TG, and IgAN on the basis of Mendelian randomization (MR) analysis. Methods: Firstly, the genome-wide association study (GWAS) summary data of IgAN (GCST90018866) and two exposure factors, TG (ukb-d-30870_raw) and HBP (ukb-a-437), were sourced from the GWAS Catalog and Integrative Epidemiology Unit (IEU) OpenGWAS databases, respectively. In this study, five methods were utilized to perform MR analysis after picking out single nucleotide polymorphisms (SNPs) as instrumental variables, including MR-Egger, weighted median, simple mode, weighted mode, and inverse variance weighted (IVW), followed by the sensitivity analysis containing the heterogeneity, horizontal pleiotropy test and leave-one-out (LOO) analysis. Finally, the enrichment analysis and interaction network construction of genes corresponding to SNPs of HBP and TG were performed. Results: The univariate MR results revealed that HBP and TG regarded as risk factors were causally related to IgAN [TG: p = 0.046, odds ratio (OR) = 1.065, 95% confidence interval (CI) = 1.001-1.133; HBP: p = 7.09 × 10-7, OR = 1.970, 95% CI = 1.507-2.575] based on random-effect IVM method, of which TG had a weaker impact. The reliability of these univariate MR results was certified by the sensitivity analysis, in which there was no horizontal pleiotropy and exaggerated influence of each SNP. Furthermore, HBP was markedly causally related to IgAN (p = 0.000512) with the help of multivariate MR analysis, rather than TG (p = 0.332). Therefore, when HBP and TG occur simultaneously, HBP is a direct influencing factor on IgAN. Ultimately, a total of 208 and 153 genes separately corresponding to SNPs of TG and HBP were included in enrichment analysis, and thereinto, genes relevant to TG were mainly enriched in lipid homeostasis and cholesterol metabolism, while genes concerned with HBP played their roles in regulation of cell growth, aldosterone synthesis and secretion and so forth. Conclusion: TG and HBP as risk factors were causally connected with IgAN, of which HBP was strongly related to the onset of IgAN, providing more reliable evidence for further exploring the relationship between TG and HBP and IgAN.

MiR-26b-5p-modified hUB-MSCs derived exosomes attenuate early brain injury during subarachnoid hemorrhage via MAT2A-mediated the p38 MAPK/STAT3 signaling pathway.

Early brain injury (EBI) is a major cause of adverse outcomes following subarachnoid hemorrhage (SAH). There is evidence that mesenchymal stem cells (MSCs) - derived exosomes are involved in the repair of SAH. Exosomes were extracted from human umbilical cord mesenchymal stem cells (hubMSCs) and identified. OxyHb treated PC12 cells were transfected with exosomes alone or together with miR-26b-5p inhibitor. Hub-MSCs derived exosomes promote cell proliferation, inhibit apoptosis and reduce inflammatory mediator expression. Transfection of miR-26b-5p inhibitor abolished the promoting effect of exosomes on the proliferation of PC12 cells, as well as the inhibitory effect on cell apoptosis. In addition, methionine adenosyltransferase II alpha (MAT2A) was one target gene of miR-26b-5p. OxyHb treated PC12 cells were transfected with exosomes alone or together with pcDNA-MAT2A and observed that the promoting effect of exosomes on PC12 cell proliferation was abolished by pcDNA-MAT2A, which was the same as the effect of miR-26b-5p inhibitor. OxyHb treated PC cells incubated with exosomes were transfected with miR-26b-5p inhibitor alone or together with si-MAT2A, respectively, and it was observed that exosomes decreased the phosphorylation levels of p38 MAPK and STAT3 proteins, inhibited cell apoptosis and inflammatory mediator expression, and miR-26b-5p inhibitor abrogated the effects of exosomes, while transfection of si-MAT2A reversed the effects of miR-26b-5p inhibitor. Moreover, injection of miR-26b-5p inhibitor resulted in increased MAT2A and pathway protein expression, increased inflammatory mediators, and aggravated neurological symptoms in the brain tissues of SAH rats.

TGFß1 alleviates axonal injury by regulating microglia/macrophages alternative activation in traumatic brain injury.

Traumatic brain injury (TBI) causes substantial mortality and long-term disability worldwide. TGFß1 is a unique molecular and functional signature in microglia, but the role of TGFß1 in TBI is not clear. The purpose of this study was to investigate the role of TGFß1 in TBI. The weight dropping device was used to establish TBI model of rats. Hematoxylin eosin staining and Bielschowsky silver staining were used to assess tissue loss. Beam walking and muscle strength tests were used to assess neurological deficits. Immunohistochemical staining was used to assess axonal injures. Western blotting was used to detect expression of related proteins. RT-PCR was used to detect expression of cytokines. Immunofluorescence staining was used to assess the microglia/macrophages activation. We observed obvious axonal injury and microglia/macrophages activation in the peri-lesion cortex. The expression of inflammatory cytokines was markedly high after TBI. The expression of TGFß1 and TGFßRI were significantly reduced after TBI. TGFß1 promoted the functional recovery and alleviated axonal injury 1 day after TBI. TGFß1 promoted microglia/macrophages polarizing to alternative activation and alleviated neuroinflammation. These effects of TGFß1 could be inhibited by LY2109761, the inhibitor of TGFRI/II. These results suggested that TGFß1 played a protective role in axonal injury and could be a potential therapeutic target in early stages following TBI.

Comprehensive assessment of deceased donor kidneys with clinical characteristics, pre-implant biopsy histopathology and hypothermic mechanical perfusion parameters is highly predictive of delayed graft function.

Background: Due to the current high demand for transplant tissue, an increasing proportion of kidney donors are considered extended criteria donors, which results in a higher incidence of delayed graft function (DGF) in organ recipients. Therefore, it is important to fully investigate the risk factors of DGF, and establish a prediction system to assess donor kidney quality before transplantation.Methods: A total of 333 donation after cardiac death kidney transplant recipients were included in this retrospective study. Both univariate and multivariate analyses were used to analyze the risk factors of DGF occurrence. Receiver operating characteristic (ROC) curves were used to analyze the predictive value of variables on DGF posttransplant.Results: The donor clinical scores, kidney histopathologic Remuzzi scores and hypothermic mechanical perfusion (HMP) parameters (flow and resistance index) were all correlated. 46 recipients developed DGF postoperatively, with an incidence of 13.8% (46/333). Multivariate logistic regression analysis of the kidney transplants revealed that the independent risk factors of DGF occurrence post-transplantation included donor score (OR = 1.12, 95% CI 1.06-1.19, p < 0.001), Remuzzi score (OR = 1.21, 95% CI 1.02-1.43, p = 0.029) and acute tubular injury (ATI) score (OR = 4.72, 95% CI 2.32-9.60, p < 0.001). Prediction of DGF with ROC curve showed that the area under the curve was increased to 0.89 when all variables (donor score, Remuzzi score, ATI score and HMP resistance index) were considered together.Conclusions: Combination of donor clinical information, kidney pre-implant histopathology and HMP parameters provide a more accurate prediction of DGF occurrence post-transplantation than any of the measures alone.

Inhibiting endogenous tissue plasminogen activator enhanced neuronal apoptosis and axonal injury after traumatic brain injury.

Tissue plasminogen activator is usually used for the treatment of acute ischemic stroke, but the role of endogenous tissue plasminogen activator in traumatic brain injury has been rarely reported. A rat model of traumatic brain injury was established by weight-drop method. The tissue plasminogen activator inhibitor neuroserpin (5 µL, 0.25 mg/mL) was injected into the lateral ventricle. Neurological function was assessed by neurological severity score. Neuronal and axonal injuries were assessed by hematoxylin-eosin staining and Bielschowsky silver staining. Protein level of endogenous tissue plasminogen activator was analyzed by western blot assay. Apoptotic marker cleaved caspase-3, neuronal marker neurofilament light chain, astrocyte marker glial fibrillary acidic protein and microglial marker Iba-1 were analyzed by immunohistochemical staining. Apoptotic cell types were detected by immunofluorescence double labeling. Apoptotic cells in the damaged cortex were detected by terminal deoxynucleotidyl transferase-mediated digoxigenin-dUTP-biotin nick-end labeling staining. Degenerating neurons in the damaged cortex were detected by Fluoro-Jade B staining. Expression of tissue plasminogen activator was increased at 6 hours, and peaked at 3 days after traumatic brain injury. Neuronal apoptosis and axonal injury were detected after traumatic brain injury. Moreover, neuroserpin enhanced neuronal apoptosis, neuronal injury and axonal injury, and activated microglia and astrocytes. Neuroserpin further deteriorated neurobehavioral function in rats with traumatic brain injury. Our findings confirm that inhibition of endogenous tissue plasminogen activator aggravates neuronal apoptosis and axonal injury after traumatic brain injury, and activates microglia and astrocytes. This study was approved by the Biomedical Ethics Committee of Animal Experiments of Shaanxi Province of China in June 2015.

Vascular endothelial growth factor A promotes platelet adhesion to collagen IV and causes early brain injury after subarachnoid hemorrhage.

The role of vascular endothelial growth factor A in platelet adhesion in cerebral microvessels in the early stage of subarachnoid hemorrhage remains unclear. In this study, the endovascular puncture method was used to produce a rat model of subarachnoid hemorrhage. Then, 30 minutes later, vascular endothelial growth factor A antagonist anti-vascular endothelial growth factor receptor 2 antibody, 10 µg, was injected into the right ventricle. Immunohistochemistry and western blot assay were used to assess expression of vascular endothelial growth factor A, occludin and claudin-5. Immunohistochemical double labeling was conducted to examine co-expression of GP Ia-II integrin and type IV collagen. TUNEL was used to detect apoptosis in the hippocampus. Neurological score was used to assess behavioral performance. After subarachnoid hemorrhage, the expression of vascular endothelial growth factor A increased in the hippocampus, while occludin and claudin-5 expression levels decreased. Co-expression of GP Ia-II integrin and type IV collagen and the number of apoptotic cells increased, whereas behavioral performance was markedly impaired. After treatment with anti-vascular endothelial growth factor receptor 2 antibody, occludin and claudin-5 expression recovered, while co-expression of GP Ia-II integrin and type IV collagen and the number of apoptotic cells decreased. Furthermore, behavioral performance improved notably. Our findings suggest that increased vascular endothelial growth factor A levels promote platelet adhesion and contribute to early brain injury after subarachnoid hemorrhage. This study was approved by the Biomedical Ethics Committee, Medical College of Xi'an Jiaotong University, China in December 2015.

Dynamic expression of nerve growth factor and its receptor TrkA after subarachnoid hemorrhage in rat brain.

Delayed ischemic neurologic deficit after subarachnoid hemorrhage results from loss of neural cells. Nerve growth factor and its receptor TrkA may promote regeneration of neural cells, but their expression after subarachnoid hemorrhage remains unclear. In the present study, a rat model of subarachnoid hemorrhage was established using two injections of autologous blood into the cistern magna. Immunohisto-chemical staining suggested that the expression of nerve growth factor and TrkA in the cerebral cortex and brainstem increased at 6 hours, peaked at 12 hours and decreased 1 day after induction of subarachnoid hemorrhage, whereas the expression in the hippocampus increased at 6 hours, peaked on day 1, and decreased 3 days later. Compared with those for the rats in the sham and saline groups, neurobehavioral scores decreased significantly 12 hours and 3 days after subarachnoid hemorrhage (P < 0.05). These results suggest that the expression of nerve growth factor and its receptor TrkA is dynamically changed in the rat brain and may thus participate in neuronal survival and nerve regeneration after subarachnoid hemorrhage.

Rapidly increased vasopressin promotes acute platelet aggregation and early brain injury after experimental subarachnoid hemorrhage in a rat model.

OBJECTIVE: To investigate the dynamic expression of vasopressin and its potential role in rat brain tissue after experimental subarachnoid hemorrhage (SAH). METHODS: Male Sprague-Dawley rats were divided into 10min, 1h, 6h, 24h, 48h and 72h groups. The SAH model was established by endovascular puncture. ELISA and immunohistochemistry were performed to evaluate dynamic expression of vasopressin. Immunohistochemistry of GPIIb/IIIa integrin was used to assess platelet aggregation. Double immunofluorescence labeling was carried out to observe the reaction between vasopressin and platelet. Early brain injury was evaluated by apoptotic cells counting. Neurobehavioral score was performed to assess neuroprotective role of SR 49059 (a selective antagonists of vasopressin receptor). RESULTS: In peripheral blood and hypothalamus, vasopressin increased rapidly at 6h and 24h. Expression of GPIIb/IIIa integrin peaked at 24h in cortex and hippocampus. Immunofluorescence showed that vasopressin and GPIIb/IIIa integrin located at the same site. Administration of SR 49059 significantly decreased platelet aggregation and number of apoptotic cells. The neurobehavioral score was promoted significantly after the intervention. CONCLUSION: The results indicate that rapidly increased vasopressin could induce platelet aggregation and contribute to early brain injury after SAH.

Etanercept alleviates early brain injury following experimental subarachnoid hemorrhage and the possible role of tumor necrosis factor-α and c-Jun N-terminal kinase pathway.

Cerebral inflammation plays a crucial role in early brain injury (EBI) after subarachnoid hemorrhage (SAH). This study investigated the effects of c-Jun N-terminal kinase (JNK) inhibitor SP600125, acetylcholine (Ach), etanercept, and anti-TNF-α on cellular apoptosis in the cerebral cortex and the hippocampus, in order to establish the role of JNK and TNF-α in EBI. The SAH model was established using an endovascular puncture protocol. The reliability of the EBI model was determined by phosphorylated-Bad (pBad) immunohistochemistry. Neurological scores were recorded and western blot was used to detect the expression of JNK and TNF-α, and TUNEL assay was used to mark apoptotic cells. The results showed that pBad positive cells were evenly distributed in the cerebral cortex at different time points. The highest expression of pBad was reached 1 day after SAH, and pJNK and TNF-α reached their peak expression at 2 days after SAH. SP600125, Ach, and etanercept significantly decreased the level of pJNK and TNF-α in the cerebral cortex and the hippocampus. In addition, SP600125 and etanercept reduced cellular apoptosis in the cerebral cortex and the hippocampus and significantly improved neurological scores at 2 days after SAH potentially via inhibition of the JNK-TNF-α pathway. Ach reduced cellular apoptosis only in the cerebral cortex. It is possible that JNK induces TNF-α expression, which in turn enhances JNK expression in EBI after SAH, leading to increased apoptosis in the cerebral cortex and the hippocampus. Thus, our results indicate that that etanercept may be a potential therapeutic agent to alleviate EBI.

Meta-analysis of the efficacy and safety of therapeutic hypothermia in children with acute traumatic brain injury.

OBJECTIVE: To evaluate the efficacy and safety of therapeutic hypothermia in children with acute traumatic brain injury (TBI). METHODS: A systematic literature review using PubMed, Embase, Cochrane Library, Chinese National Knowledge Infrastructure, Wanfang, VIP, and Chinese Biomedical Database was performed to retrieve studies of randomized controlled trials (RCTs) on therapeutic hypothermia for children with TBI published before March 2014. Data extraction and quality evaluation of RCTs were performed by 2 investigators independently. A meta-analysis was performed by RevMan 5.2.7. RESULTS: There were 7 RCTs comprising 442 children (218 in hypothermia group and 224 in normothermia group). Meta-analysis showed therapeutic hypothermia could increase mortality compared with the normothermia group (relative risk [RR] = 1.84, 95% confidence interval [CI] = 1.15-2.93, P = 0.01). On the Glasgow Outcome Scale (GOS), the following scores did not differ between the hypothermia group and normothermia group: 3-month GOS 4-5 (RR = 0.89, 95% CI = 0.68-1.16, P = 0.39), 3-month GOS 1-3 (RR = 1.19, 95% CI = 0.80-1.76, P = 0.39), 6-month GOS 4-5 (RR = 0.91, 95% CI = 0.78-1.07, P = 0.26), and 6-month GOS 1-3 (RR = 1.18, 95% CI = 0.88-1.59, P = 0.27). Hypothermia did not increase the rate of pneumonia (RR = 0.84, 95% CI = 0.63-1.12, P = 0.23) or bleeding (RR = 0.94, 95% CI = 0.39-2.26, P = 0.89), but the incidence of arrhythmias was higher in the hypothermia group (RR = 2.60, 95% CI = 1.06-6.41, P = 0.04). CONCLUSIONS: No benefit of therapeutic hypothermia in children with TBI is shown in this study; therapeutic hypothermia may increase the risk of mortality and arrhythmia. There is no evidence that therapeutic hypothermia improves prognosis of children with TBI; there is also no evidence that therapeutic hypothermia increases the risk of pneumonia and coagulation dysfunction. These results are limited by the quality of the included studies and need to be considered with caution. Further large-scale, well-designed RCTs on this topic are needed.

Mutation identification of the DSPP in a Chinese family with DGI-II and an up-to-date bioinformatic analysis.

In this study, through linkage analysis of a four-generation Chinese family with multiple members afflicted with DGI (type II), we identified a novel missense mutation in DSPP. The mutation was located in exon 2 at the second nucleotide position of the last codon and resulted in a substitution of a proline with a leucine residue (c.50C>T, p.P17L, g.50C>T). To assess the potential effects of this novel mutation, we utilized various bioinformatics analysis programs. The results indicate that the mutation likely affects protein cleavage/trafficking. We also analyzed previously reported mutations of DSPP. In summary, our finding supports that the genomic sequence that corresponds to the P17 residue of DSPP is a mutational hotspot and P17 may be critical for the function of DSPP.