Salvaging donated kidneys from prolonged warm ischemia during ex vivo hypothermic oxygenated perfusion.

Prolonged warm ischemic is the main cause discarding donated organs after cardiac death. Here, we identified that prolonged warm ischemic time induced disseminated intravascular coagulation and severe capillary vasospasm after cardiac death of rat kidneys. Additionally, we found a significant accumulation of fibrinogen in a hypoxic cell culture of human umbilical vein epithelial cells and in isolated kidneys exposed to prolonged warm ischemic following flushing out of blood. However, pre-flushing the kidney with snake venom plasmin in a 90-minute warm ischemic model maximized removal of micro thrombi and facilitated the delivery of oxygen and therapeutic agents. Application of carbon monoxide-releasing CORM-401 during ex vivo hypothermic oxygenated perfusion achieved multipath protective effects in prolonged warm ischemic kidneys. This led to significant improvements in perfusion parameters, restoration of the microcirculation, amelioration of mitochondrial injury, oxidative stress, and apoptosis. This benefit resulted in significantly prolonged warm ischemic kidney recipient survival rates of 70%, compared with none in those receiving ex vivo hypothermic oxygenated perfusion alone. Significantly, ex vivo hypothermic oxygenated perfusion combined with cytoprotective carbon monoxide releasing CORM-401 treatment meaningfully protected the donated kidney after cardiac death from ischemia-reperfusion injury by reducing inflammation, oxidative stress, apoptosis, and pathological damage. Thus, our study suggests a new combination treatment strategy to potentially expand the donor pool by increasing use of organs after cardiac death and salvaging prolonged warm ischemic kidneys.

Association between Triglyceride-Glucose Index and 1-year Recurrent Stroke after Acute Ischemic Stroke: Results from the Xi'an Stroke Registry Study of China.

INTRODUCTION: The triglyceride-glucose (TyG) index is reported to be related to poor functional outcomes and all-cause mortality post-stroke. However, the association between TyG index and recurrent stroke after acute ischemic stroke (AIS) has not been well described. We aimed to identify whether the TyG index was associated with 1-year recurrent stroke after AIS. METHODS: Baseline patient information was collected at admission, and the TyG index was calculated. Recurrent stroke events were followed up at 1, 3, 6, and 12 months after diagnosis. We then examined the association between the TyG index and risk of 1-year recurrent stroke using multivariable Cox regression models and restricted cubic spline analyses. RESULTS: Among 2,288 participants, the mean TyG index was 8.8  0.7. Those in the fourth quartile (Q4) demonstrated higher recurrent stroke risk than those in Q1 (adjusted hazard ratio [HR] = 1.63; 95% confidence interval [CI], 0.98-2.72; p = 0.059). Subgroup analysis revealed a sex-specific association between TyG index and recurrent stroke (p for interaction = 0.022). Additionally, restricted cubic splines analyses showed a non-linear association between the TyG index and 1-year recurrent stroke. In females, patients in the Q4 had a 2.95-fold increased recurrent stroke risk than did patients in the Q1 (adjusted HR =2.95; 95% CI, 1.09-7.94; p = 0.032); the risk increased when the TyG index was > 8.73. However, no significant correlation was observed in males. CONCLUSION: A non-linear association was found between the TyG index and 1-year recurrent stroke risk. Subsequently, a high TyG index could predict an increased 1-year recurrent stroke risk in female AIS patients.

Hypothermic oxygenated perfusion attenuates DCD liver ischemia-reperfusion injury by activating the JAK2/STAT3/HAX1 pathway to regulate endoplasmic reticulum stress.

BACKGROUND: Hepatic ischemia-reperfusion injury (IRI) in donation after cardiac death (DCD) donors is a major determinant of transplantation success. Endoplasmic reticulum (ER) stress plays a key role in hepatic IRI, with potential involvement of the Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) pathway and the antiapoptotic protein hematopoietic-lineage substrate-1-associated protein X-1 (HAX1). In this study, we aimed to investigate the effects of hypothermic oxygenated perfusion (HOPE), an organ preservation modality, on ER stress and apoptosis during hepatic IRI in a DCD rat model. METHODS: To investigate whether HOPE could improve IRI in DCD livers, levels of different related proteins were examined by western blotting and quantitative real-time polymerase chain reaction. Further expression analyses, immunohistochemical analyses, immunofluorescence staining, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining, and transmission electron microscopy were conducted to analyze the effects of HOPE on ER stress and apoptosis. To clarify the role of the JAK2/STAT3 pathway and HAX1 in this process, AG490 inhibitor, JAX1 plasmid transfection, co-immunoprecipitation (CO-IP), and flow cytometry analyses were conducted. RESULTS: HOPE reduced liver injury and inflammation while alleviating ER stress and apoptosis in the DCD rat model. Mechanistically, HOPE inhibited unfolded protein responses by activating the JAK2/STAT3 pathway, thus reducing ER stress and apoptosis. Moreover, the activated JAK2/STAT3 pathway upregulated HAX1, promoting the interaction between HAX1 and SERCA2b to maintain ER calcium homeostasis. Upregulated HAX1 also modulated ER stress and apoptosis by inhibiting the inositol-requiring enzyme 1 (IRE1) pathway. CONCLUSIONS: JAK2/STAT3-mediated upregulation of HAX1 during HOPE alleviates hepatic ER stress and apoptosis, indicating the JAK2/STAT3/HAX1 pathway as a potential target for IRI management during DCD liver transplantation.

Elevated non-HDL-C/HDL-C ratio increases the 1-year risk of recurrent stroke in older patients with non-disabling ischemic cerebrovascular events: results from the Xi'an Stroke Registry Study of China.

BACKGROUND: Few studies have explored the prognostic role of nontraditional lipid-related indicators in non-disabling ischemic cerebrovascular events (NICE). In this study, we aimed to investigate the relationship between the ratio of non-high-density lipoprotein cholesterol to high-density lipoprotein cholesterol (non-HDL-C/HDL-C) and the1-year risk of recurrent stroke in patients with NICE. METHODS: Total cholesterol (TC), HDL-C, and patient information were collected at admission. Recurrent stroke events were followed up 3, 6, and 12 months after onset. Non-HDL-C levels were calculated by subtracting HDL-C from TC. The non-HDL-C/HDL-C ratio was treated as a continuous variable and in quartiles (Q1-Q4). Stratified multivariate Cox regression was used to investigate the relationship between the non-HDL-C/HDL-C ratio and the 1-year risk of recurrent stroke in patients with NICE. RESULTS: Overall, 1,659 patients with NICE were enrolled. For each unit increase in the non-HDL-C/HDL-C ratio, the 1-year risk of recurrent stroke in patients aged ≥ 65 years (older patients) with NICE increased by 64% in the adjusted model (hazard ratio [HR]: 1.64, 95%confidence interval [CI]:1.18-2.27, P = 0.003), and the HRs were 3.21 and 4.24 times higher in the Q3 and Q4 groups than that in the Q1 group, which was considered to be the reference (adjusted model Q3: HR: 3.21, 95%CI: 1.05-9.83, P = 0.041; adjusted model Q4: HR: 4.24, 95%CI: 1.30-13.85, P = 0.017). However, there was no significant difference in patients younger than 65 years. Both curve fitting and Kaplan-Meier cumulative risk analysis showed that an elevated non-HDL-C/HDL-C ratio significantly increased the 1-year risk of recurrent stroke in older patients with NICE. The optimal range for the non-HDL-C/HDL-C ratio should be no higher than the Q2 group (2.256-2.939). Stratified Cox regression analysis showed that these results tended to be stable for different comorbidities (all P for interaction > 0.05). CONCLUSIONS: Elevated non-HDL-C/HDL-C ratios significantly increased the 1-year risk of recurrent stroke in older patients with NICE. Therefore, clinicians need to pay more attention to this indicator when managing older patients with NICE.

Pachymic acid protects hepatic cells against oxygen-glucose deprivation/reperfusion injury by activating sirtuin 1 to inhibit HMGB1 acetylation and inflammatory signaling.

Ischemia-reperfusion injury is an important cause of liver injury occurring during liver transplantation. It is usually caused by inflammatory response and oxidative stress-induced oxidative damage. Pachymic acid (PA) has various biological activities such as anti-inflammatory, antioxidant and anti-cancer. However, the action mechanism of PA in hepatic ischemia-reperfusion injury is currently unknown. In this study, liver cells were subjected to oxygen-glucose deprivation/reperfusion (OGD/R) to simulate a hepatic ischemia-reperfusion injury model. The binding relationship between PA and sirtuin 1 (SIRT1) was analyzed by molecular docking. Cell viability was detected by Cell Counting Kit-8. Expression levels of SIRT1 and high mobility group box 1 (HMGB1) were detected by western blot. Subsequent levels of inflammatory factors were detected by related kits and western blot. Meanwhile, related kits were used to examine levels of oxidative stress markers including reactive oxygen species, malondialdehyde, superoxide dismutase and cytotoxicity-associated lactate dehydrogenase. Finally, cell apoptosis was detected by flow cytometry and western blot. The results showed that PA significantly ameliorated OGD/R-induced decrease in SIRT1 expression, increase in HMGB1 acetylation and HMGB1 translocation. Moreover, the elevated levels of inflammatory factors, oxidative stress indexes and cell apoptosis upon exposure to OGD/R were reversed by PA treatment. Moreover, the addition of SIRT1 agonist and inhibitor further demonstrated that PA exerted the aforementioned effects in OGD/R-exposed cells by targeting SIRT1. Thus, the present study revealed the mechanism by which PA ameliorated OGD/R-induced hepatic injury via SIRT1. These results might provide a clearer theoretical basis for the targeted treatment of OGD/R-induced hepatic injury with PA.

Machine perfusion combined with antibiotics prevents donor-derived infections caused by multidrug-resistant bacteria.

Donor infection affects organ utilization, especially the infections by multidrug-resistant bacteria, which may have disastrous outcomes. We established a rat model, inoculated with Escherichia coli or carbapenem-resistant Klebsiella pneumoniae (CRKP), to investigate whether hypothermic machine perfusion (HMP), normothermic machine perfusion (NMP), or static cold storage (SCS) combined with antibiotic (AB) could eliminate the bacteria. E. coli or CRKP-infected kidneys were treated with cefoperazone-sulbactam and tigecycline, respectively. The HMP+AB and NMP+AB treatments had significant therapeutic effects on E. coli or CRKP infection compared with the SCS+AB treatment. The bacterial load of CRKP-infected kidneys in the HMP+AB (22 050 ± 2884 CFU/g vs. 1900 ± 400 CFU/g, p = .007) and NMP+AB groups (25 433 ± 2059 CFU/g vs. 500 ± 458 CFU/g, p = .002) were significantly reduced, with no statistically significant difference between both groups. Subsequently, the CRKP-infected kidneys of the HMP+AB and SCS+AB groups were transplanted. The rats in the SCS+AB group were severe infected and euthanized on day 4 post-transplant. By contrast, the rats in the HMP+AB group were in good condition. In conclusion, HMP and NMP combined with AB seems to be efficient approaches to decrease bacterial load of infected kidneys. This might lead to higher utilization rates of donors with active infection.

Mild hypothermia ameliorates hepatic ischemia reperfusion injury by inducing RBM3 expression.

Liver ischemia reperfusion injury (IRI) is a serious complication of certain liver surgeries, and it is difficult to prevent. As a potential drug-free treatment, mild hypothermia has been shown to promote positive outcomes in patients with IRI. However, the protective mechanism remains unclear. We established in vivo and in vitro models of hepatic ischemia reperfusion (IR) and mild hypothermia pretreatment. Hepatocytes were transfected with RNA-binding motif protein 3 (RBM3) overexpression plasmids, and IR was performed. Cell, culture medium, blood and tissue samples were collected to assess hepatic injury, oxidative stress, apoptosis and changes in RBM3 expression in the liver. Upregulation of RBM3 expression by mild hypothermia reduced the aminotransferase release, liver tissue injury and mitochondrial injury induced by liver IR. Hepatic IR-induced p38 and c-Jun N-terminal kinase (JNK) signaling pathway activation, oxidative stress injury and apoptosis could be greatly reversed by mild hypothermia. Overexpression of RBM3 mimicked the hepatoprotective effect of mild hypothermia. Mild hypothermia protects the liver from ischemia reperfusion-induced p38 and JNK signaling pathway activation, oxidative stress injury and apoptosis through the upregulation of RBM3 expression.

Relationship between serum alkaline phosphatase and poor 3-month prognosis in acute ischemic stroke patients with preserved renal function: results from Xi'an Stroke Registry Study of China.

BACKGROUND: In recent years, alkaline phosphatase (ALP) has been considered as one of the independent risk factors of acute ischemic stroke (AIS) and leads to worse clinical outcomes in patients with renal failure. In this study, we aim to investigate whether serum ALP level is associated with poor early-term prognosis in relationship of AIS patients with preserved renal function. METHODS: A prospectively collected database of AIS patients hospitalized in the Xi'an district of China from January to December, 2015 was analyzed. The demographics, serum ALP levels and stroke outcomes of all patients at 3 months were reviewed. Patients were routinely followed-up for 3 months. Serum ALP level was analyzed as a continuous variable and quintiles (Q1-Q5). Multivariate logistic regression model and a two-piecewise linear regression model were used to investigate the relationship and to determine the threshold effect regarding serum ALP levels and poor 3-month prognosis of AIS patients with preserved renal function. RESULTS: Overall, 1922 AIS patients were enrolled with 62.3% of them being men. The risk of having a poor 3-month prognosis was significantly increased in Q1, Q2, Q3 and Q5, when compared to that in Q4 being as the reference. The highest risk was noted in Q5 (odds ratio 2.21, 95% confidence interval: 1.32-3.73, P = 0.003) after being adjusted for confounders. Further analysis revealed a J-shaped curvilinear relationship between ALP levels and a poor 3-month prognosis of strokes (optimal threshold ALP level = 90 U/L). The relationship between both parameters was not significantly affected by age, sex, drinking, hypertension and leukocyte count (stratified by 10 × 109/L) (P for interaction > 0.05). CONCLUSIONS: Serum ALP was noted as an independent risk factor for a poor 3-month prognosis of AIS patients with preserved renal function. ALP levels higher than 90 U/L could cause an increased risk of a poor 3-month prognosis.

Efficacy of Interferon-Based Therapy for COVID-19: A Systematic Review and Meta-Analysis.

Background: The aim of this study was to determine the efficacy of interferon (IFN)-based therapy for coronavirus disease 2019 (COVID-19) based on relevant qualified studies. We searched for pertinent studies using keywords via PubMed, Cochrane and Embase databases. Studies from other pertinent sources and that were published before September 2021 were also reviewed. Methods: For each study, we assessed and synthesized the outcomes by relative risk (RR) or weighted mean difference (WMD) combined with a 95% confidence interval (CI). A total of 8 studies involving 2442 patients with COVID-19 were evaluated in this meta-analysis. Results: The IFN group had a significant decrease in ICU admissions (RR: 0.705; 95% CI, 0.515-0.964) and death (RR: 0.416; 95% CI, 0.217-0.797), and increased duration of ICU stay (WMD: 0.996; 95% CI, 0.834-1.158) compared with the control group in the randomized clinical trial (RCT) subgroup analysis. In non-RCT subgroup analysis, the IFN group showed a significant increase in discharge rate (RR: 1.052; 95% CI, 1.004-1.101) compared with the control group. Conclusion: IFN therapy appears to have better efficacy than non-IFN therapy as sedatives in patients with COVID-19 in terms of decreasing ICU admissions and death and increasing discharge. However, more high-quality RCTs are needed to confirm these findings.

Mild hypothermia pretreatment extenuates liver ischemia-reperfusion injury through Rab7-mediated autophagosomes-lysosomes fusion.

Liver ischemia-reperfusion (IR) injury is an unavoidable pathological process in transplantation, closely related to poor prognosis. To date, there has been no clear therapeutic measure. We previously reported that mild hypothermia (MH), a widely used therapy, can exert significant protective effect against liver IR injury. Among the multiple mechanisms underlying the therapeutic effect of MH, autophagy flux drew our special attention. In this study, we evaluated the role of autophagy flux in IR injury and thereby explored the relationship between MH and autophagy flux in IR injury. We developed in vivo and in vitro models for hepatic IR injury. By autophagy flux assay with Western blotting and immunofluorescence, we found that MH restricts heavy accumulation of autophagosomes (APs) during IR injury. Activation and blocking of the autophagy flux unraveled that accumulation of APs further aggravated IR injury. Further, MH reduces APs accumulation to restore autophagy flux by regulating the fusion of APs and lysosomes. Besides, MH upregulated the level of Rab7 protein expression that was seriously impaired during IR injury. Inhibition of Rab7 expression increased apoptosis of liver cells and reduced the degree of overlap between APs and lysosomes. The results were reversed upon activation of Rab7. In conclusion, MH can alleviate liver IR injury by regulating the Rab7-mediated APs-lysosomes fusion that reduces APs accumulation. This can provide a theoretical basis for the further application of MH in related clinical diseases.

Dorsolateral medullary infarction registry: a study protocol for a prospective, multicentric registry.

BACKGROUND: Dorsolateral medullary infarction is a typical cerebral infarction which is characterized by Wallenberg's syndrome. Neurotrophic keratopathy is an uncommon consequence of dorsolateral medullary infarction. At present, the protocol is aimed to study the dynamic changes in corneal innervation and the ocular surface environment after dorsolateral medullary infarction. METHODS: This study will involve consecutive data from all medical records of patients within 7 days of acute dorsolateral medullary infarction onset at the Departments of Neurology from 10 collaborating stroke centers. Eligible patients will mainly be characterized based on detailed physical examinations, multimodal imaging, and corneal related examinations and patients will be followed-up for 2 years. Neurotrophic keratopathy after dorsolateral medullary infarction is the primary endpoint. The dynamic histological corneal innervation and ocular surface environment after dorsolateral medullary infarction will be observed during the follow-up period. DISCUSSION: This multicentric, prospective registry is the first to identify and characterize the dynamic changes of corneal innervation and the ocular surface environment after acute dorsolateral medullary infarction. The significance of the study is to emphasize that the curative effect is based on the doctors' identification of the disease in the earliest stage before irreversible damage occurs to the cornea. TRIAL REGISTRATION: The registry was registered ( ChiCTR-OPC-17,011,625 ) on June 11, 2017.

Risk factors affecting the 1-year outcomes of minor ischemic stroke: results from Xi'an stroke registry study of China.

BACKGROUND: The prevalence of stroke recurrence, disability, and all-cause mortality of patients with minor ischemic stroke (MIS) remains problematic. The aim of the present study was to identify risk factors associated with adverse outcomes at 1 year after MIS in the Xi'an region of China. METHODS: This prospective cohort study included MIS patients above 18 years old with National Institutes of Health Stroke Scale (NIHSS) score ≤ 3 who were treated in any of four hospitals in Xi'an region of China between January and December 2015. The 1-year prevalence of stroke recurrence, disability, and all-cause mortality were evaluated, respectively. Multivariate logistic regression analysis was performed to assess the association between the identified risk factors and clinical outcomes. RESULTS: In this study, 131(10.5%, 131/1252) patients were lost to follow-up at 1 year. A total of 1121 patients were included for analysis, the prevalence of stroke recurrence, disability, and all-cause mortality at 1 year after MIS were 3.4% (38/1121), 9.3% (104/1121), and 3.3% (37/1121), respectively. Multivariate logistic regression analysis identified age, current smoking, and pneumonia as independent risk factors for stroke recurrence. Age, pneumonia, and alkaline phosphatase were independent risk factors for all-cause mortality. Independent risk factors for disability were age, pneumonia, NIHSS score on admission, and leukocyte count. CONCLUSIONS: The 1-year outcomes of MIS in Xi'an region of China were not optimistic, especially with a high prevalence of disability. The present study indicated that age and pneumonia were the common independent risk factors affecting the 1-year outcomes of MIS in Xi'an region of China.

Donor Treatment With a Hypoxia-Inducible Factor-1 Agonist Prevents Donation After Cardiac Death Liver Graft Injury in a Rat Isolated Perfusion Model.

The protective role of hypoxia-inducible factor-1 (HIF-1) against liver ischemia-reperfusion injury has been well proved. However its role in liver donation and preservation from donation after cardiac death (DCD) is still unknown. The objective of this study was to test the hypothesis that pharmaceutical stabilization of HIF-1 in DCD donors would result in a better graft liver condition. Male SD rats (6 animals per group) were randomly given the synthetic prolyl hydroxylase domain inhibitor FG-4592 (Selleck, 6 mg/kg of body weight) or its vehicle (dimethylsulfoxide). Six hours later, cardiac arrest was induced by bilateral pneumothorax. Rat livers were retrieved 30 min after cardiac arrest, and subsequently cold stored in University of Wisconsin solution for 24 h. They were reperfused for 60 min with Krebs-Henseleit bicarbonate buffer in an isolated perfused liver model, after which the perfusate and liver tissues were investigated. Pretreatment with FG-4592 in DCD donors significantly improved graft function with increased bile production and synthesis of adenosine triphosphate, decreased perfusate liver enzyme release, histology injury scores and oxidative stress-induced cell injury and apoptosis after reperfusion with the isolated perfused liver model. The beneficial effects of FG-4592 is attributed in part to the accumulation of HIF-1 and ultimately increased PDK1 production. Pretreatment with FG-4592 in DCD donors resulted in activation of the HIF-1 pathway and subsequently protected liver grafts from warm ischemia and cold-stored injury. These data suggest that the pharmacological HIF-1 induction may provide a clinically applicable therapeutic intervention to prevent injury to DCD allografts.

Outcome Improvement for Hypothermic Machine Perfusion Versus Cold Storage for Kidneys From Cardiac Death Donors.

Organ shortage has led to an increased use of kidneys from cardiac death donors (DCDs), but controversies about the methods of organ preservation still exist. This study aims to compare the effect of machine perfusion (MP) and cold storage (CS) in protecting kidneys harvested from DCDs. 141 kidney pairs from DCDs between July 2010 and July 2015 were included in this randomized controlled study. One kidney from each donor was randomly assigned to MP and the contralateral kidney was assigned to CS. Delayed graft function (DGF) rate, resistance index of renal arteries, early renal function, and survival rates were used to estimate the effect of preservation. The results showed that MP decreased the rate of DGF from 33.3 to 22.0% (P = 0.033). Ultrasound of the kidneys within 48 h after transplantation showed that the resistance index of renal main artery (0.673 ± 0.063 vs. 0.793 ± 0.124, P < 0.001), sub segmental artery (0.66 ± 0.062 vs. 0.764 ± 0.077, P < 0.001) and interlobular artery (0.648 ± 0.056 vs. 0.745 ± 0.111, P = 0.023) were all significantly lower in the MP group than those in the CS group. Furthermore, compared to the CS group, in the first 7 days following transplantation, the median urine volume was significantly higher (4080 mL vs. 3000 mL, P = 0.047) in kidneys sustained using MP and the median serum creatinine was remarkably lower (180 µmol/L vs. 390 µmol/L, P = 0.024). More importantly, MP group had higher 1- and 3-year graft survival rates (98% vs. 93%, P = 0.026; 93% vs. 82%, P = 0.036, respectively). Hypothermic MP improved the outcomes of DCD kidney transplantation.

Mechanisms of Hypothermic Machine Perfusion to Decrease Donation After Cardiac Death Graft Inflammation: Through the Pathway of Upregulating Expression of KLF2 and Inhibiting TGF-ß Signaling.

Hypothermic machine perfusion (HMP) has been known as an efficient way to improve kidney graft function, but the underlying mechanisms remain unclear. Here, we adopt a rabbit reperfusion mode to investigate the upstream mechanisms of end-ischemic HMP of kidneys from donors after cardiac death (DCD), with static cold storage (CS) as a control. Eighteen New Zealand healthy male rabbits (12 weeks old, with a weight of 3.0 ± 0.2 kg) were randomly divided into three groups: HMP group, CS group, and Normal group (n = 6). The left kidney of rabbits underwent warm ischemia for 25 min through clamping the left renal pedicle and then reperfusion for 1 h. Then the left kidneys were preserved by CS or HMP (4°C for 4 h) ex vivo respectively, after they were autotransplanted and rabbits were submitted to a right nephrectomy. Twenty-four hours after reperfusion, all left renal specimens were collected. Finally, the expression of Krüppel-like factor 2 (KLF2), transforming growth factor-ß (TGF-ß) and SMAD4 protein in renal cortical tissue were detected by immunoblotting, and the TGF-ß and SMAD4 expressions were further confirmed by immunohistochemistry analysis. We found that expression of KLF2 in HMP group was significantly higher than CS group (P = 0.011), while expression of TGF-ß and SMAD4 in HMP group were significantly lower than CS group (P = 0.002, P = 0.01, respectively); Compared with normal group, the expression of TGF-ß and SMAD4 in HMP and CS group significantly increased (P<0.05). Compared with CS group, TGF-ß and SMAD4 protein were equally down-regulated in glomerular and the tubular epithelial cells in HMP group confirmed by immunohistochemistry. In conclusion, HMP may decrease DCD kidneys inflammation through the pathway of upregulating expression of KLF2 and inhibiting TGF-ß signaling after transplantation.

Increased Expression of Aldehyde Dehydrogenase 2 Reduces Renal Cell Apoptosis During Ischemia/Reperfusion Injury After Hypothermic Machine Perfusion.

Hypothermic machine perfusion (MP) can reduce graft's injury after kidney transplantation; however, the mechanism has not been elucidated. In the past decade, many studies showed that aldehyde dehydrogenase 2 (ALDH2) is a protease which can inhibit cell apoptosis. Therefore, this study aims to explore whether ALDH2 takes part in reducing organ damage after MP. Eighteen healthy male New Zealand rabbits (12 weeks old, weight 3.0 ± 0.3 kg) were randomly divided into three groups: normal group, MP group, and cold storage (CS) group (n = 6). The left kidney of rabbits underwent warm ischemia for 35 min through clamping the left renal pedicle and then reperfusion for 1 h. Left kidneys were preserved by MP or CS (4°C for 4 h) in vivo followed by the right nephrectomy and 24-h reperfusion, and then the specimens and blood were collected. Finally, concentration of urine creatinine (Cr), blood urea nitrogen (BUN), and 4-HNE were tested. Renal apoptosis was detected by TUNEL staining, and the expression of ALDH2, cleaved-caspase 3, bcl-2/ bax, MAPK in renal tissue was detected by immunohistochemistry or Western blot; 24 h after surgery, the concentration of Cr in MP group was 355 ± 71µmol/L, in CS group was 511 ± 44 µmol/L (P < 0.05), while the BUN was 15.02 ± 2.34 mmol/L in MP group, 22.64 ± 3.58 mmol/L in CS group (P < 0.05). The rate of apoptosis and expression of cleaved caspase-3, p-P38, p-ERK, and p-JNK in MP group was significantly lower than that in CS group (P < 0.05), while expression of ALDH2 and bcl-2/bax in MP group was significantly higher than that in CS group (P < 0.05); expression of cleaved caspase-3 in both MP and CS group significantly increased as compared with that in normal group (P < 0.05). In conclusion, increased expression of ALDH2 can reduce the renal cell apoptosis through inhibiting MAPK pathway during ischemia/reperfusion injury (IRI) after hypothermic MP.

[Establishment and application of efficient nematicidal screening model in Bacillus amyloliquefaciens].

OBJECTIVE: The mechanisms of nematophagous bacteria against nematodes remain unclear, limiting the use of biocontrol bacteria in the agriculture. Therefore, we constructed a rapid and efficient screening model to quickly identify new candidate genes involved in nematode infection. METHODS: The wild-type Bacillus amyloliquefaciens FZB42 as well as more than 400 random mutants were inoculated into 5 mL liquid bioassay medium. After growth at 37 degrees C for 24 h, 200 microL bacterial culture and 50-60 Level 4 age nematodes were added to 24-well plates, and then the survival rates of nematodes were determined at different time points. Through several rescreening, we selected the mutant strains whose nematicidal activities significantly decreased compared with the wild-type strain. Meanwhile, the conventional bioassay of solid plate was used as control. RESULTS: Two mutants (F1 and F2) with obvious decreased nematicidal activities were selected from the random mutation library by liquid bioassay, consistent with the result of conventional solid plate bioassay. By comparing to 168 h-screening in each round of the solid plate bioassay, the method of liquid bioassay required only 24 h. The result indicated that the liquid bioassay greatly reduced the experimental time. CONCLUSION: Our current study has successfully constructed a rapid and efficient method to bioassay the nematicidal activity, which could also lay the foundation for further cloning the candidate genes involved in the microbial infection against nematodes.

Hypothermic machine perfusion reduces donation after circulatory death liver ischemia-reperfusion injury through the SERPINA3-mediated PI3Kδ/Akt pathway.

Hypothermic machine perfusion (HMP) has been demonstrated to be more effective in mitigating ischemia-reperfusion injury (IRI) of donation after circulatory death (DCD) organs than cold storage (CS), yet the underlying mechanism remains obscure. We aimed to propose a novel therapeutic approach to ameliorate IRI in DCD liver transplantation. Twelve clinical liver samples were randomly assigned to HMP or CS treatment and subsequent transcriptomics analysis was performed. By combining in vivo HMP models, we discovered that HMP attenuated inflammation, oxidative stress, and apoptosis in DCD liver through a SEPRINA3-mediated PI3Kδ/AKT signaling cascade. Moreover, in the hypoxia/reoxygenation (H/R) model of BRL-3A, overexpression of SERPINA3 mitigated H/R-induced apoptosis, while SERPINA3 knockdown exacerbated cell injury. Idelalisib (IDE) treatment also reversed the protective effect of SERPINA3 overexpression. Overall, our research provided new insights into therapeutic strategies and identified potential novel molecular targets for therapeutic intervention against DCD liver.

ALDH2 deficiency exacerbates MCD-diet induced MASLD by modulating bile acid metabolism.

Aldehyde dehydrogenase 2 (ALDH2), an acetaldehyde dehydrogenase in mitochondria, is primarily responsible for metabolizing alcohol-derived acetaldehyde and other endogenous aldehydes. Inactivating ALDH2 rs671 polymorphism is found in up to 8 % of the global population and 40 % of the East Asian population. Recent studies have shown that rs671 SNP mutation in the human ALDH2 gene is associated with an increased risk of metabolic dysfunction-associated steatotic liver diseases (MASLD), but the mechanism remains unclear. Here, we identify the role of ALDH2 in MASLD. Firstly, ALDH2 activity was lower in MASLD patients and the methionine-choline deficiency (MCD) diet induced MASLD model. Secondly, activation of ALDH2 activity with Alda-1 (ALDH2 agonist) attenuated MCD-diet induced hepatic triglyceride (TG) accumulation and steatosis, whereas the opposite result was observed with cyanamide (CYA, ALDH2 inhibitor). Furthermore, ALDH2 deficiency exacerbated hepatic steatosis, inflammation, and fibrosis in the MCD-diet induced mice. RNA sequencing (RNA-seq) revealed that oxysterol 7-α hydroxylase (Cyp7b1) and the related metabolic pathway significantly changed in the MCD-diet challenged ALDH2-/- mice. In ALDH2-/- mice, the expression of Cyp7b1 was downregulated and FXR/SHP signaling was inhibited, reducing the alternative bile acid (BA) synthetic pathway. In our in vitro experiments, knockdown of ALDH2 exacerbated TG accumulation in hepatocytes, whereas the opposite result was observed with overexpression of ALDH2. Moreover, chenodeoxycholic acid (CDCA) rescued ALDH2 downregulation induced TG accumulation in hepatocytes. Our study reveals that ALDH2 attenuates hepatocyte steatosis by regulating the alternative BA synthesis pathway, and ALDH2 may serve as a potential target for the treatment of MASLD.

The highly modified microcin peptide plantazolicin is associated with nematicidal activity of Bacillus amyloliquefaciens FZB42.

Bacillus amyloliquefaciens FZB42 has been shown to stimulate plant growth and to suppress the growth of plant pathogenic organisms including nematodes. However, the mechanism underlying its effect against nematodes remains unknown. In this study, we screened a random mutant library of B. amyloliquefaciens FZB42 generated by the mariner transposon TnYLB-1 and identified a mutant strain F5 with attenuated nematicidal activity. Reversible polymerase chain reaction revealed that three candidate genes RAMB_007470, yhdY, and prkA that were disrupted by the transposon in strain F5 potentially contributed to its decreased nematicidal activity. Bioassay of mutants impaired in the three candidate genes demonstrated that directed deletion of gene RBAM_007470 resulted in loss of nematicidal activity comparable with that of the F5 triple mutant. RBAM_007470 has been reported as being involved in biosynthesis of plantazolicin, a thiazole/oxazole-modified microcin with hitherto unknown function. Electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS) analyses of surface extracts revealed that plantazolicin bearing a molecular weight of 1,354 Da was present in wild-type B. amyloliquefaciens FZB42, but absent in the ΔRABM_007470 mutant. Furthermore, bioassay of the organic extract containing plantazolicin also showed a moderate nematicidal activity. We conclude that a novel gene RBAM_007470 and its related metabolite are involved in the antagonistic effect exerted by B. amyloliquefaciens FZB42 against nematodes.