Metformin alleviates lung ischemia-reperfusion injury in a rat lung transplantation model.

Background: Lung ischemia-reperfusion injury (LIRI) is among the complications observed after lung transplantation and is associated with morbidity and mortality. Preconditioning of the donor lung before organ retrieval may improve organ quality after transplantation. We investigated whether preconditioning with metformin (Met) ameliorates LIRI after lung transplantation. Methods: Twenty Lewis rats were randomly divided into the sham, LIRI, and Met groups. The rats in the LIRI and Met groups received saline and Met, respectively, via oral gavage. Subsequently, a donor lung was harvested and kept in cold storage for 8 h. The LIRI and Met groups then underwent left lung transplantation. After 2 h of reperfusion, serum and transplanted lung tissues were examined. Results: The partial pressure of oxygen (PaO2) was greater in the Met group than in the LIRI group. In the Met group, wet-to-dry (W/D) weight ratios, inflammatory factor levels, oxidative stress levels and apoptosis levels were notably decreased. Conclusions: Met protects against ischemia-reperfusion injury after lung transplantation in rats, and its therapeutic effect is associated with its anti-inflammatory, antioxidative, and antiapoptotic properties.

[Risk factors of early death after lung transplantation in patients with idiopathic pulmonary fibrosis complicated with pulmonary arterial hypertension].

OBJECTIVE: To investigate the risk factors of early death after lung transplantation in patients with idiopathic pulmonary fibrosis (IPF) complicated with pulmonary arterial hypertension (PAH). METHODS: A retrospective cohort study was conducted. The clinical data of 134 patients with IPF and PAH who underwent lung transplantation at Wuxi People's Hospital Affiliated to Nanjing Medical University from January 2017 to December 2020 were collected. The donor's gender, age, duration of mechanical ventilation, and cold ischemia time, the recipient's gender, age, body mass index (BMI), smoking, history of hypertension and diabetes, preoperative usage of hormones, mean pulmonary arterial pressure (mPAP), cardiac echocardiography and cardiac function, serum creatinine (SCr), N-terminal pro-brain natriuretic peptide (NT-proBNP) as well as surgical type, extracorporeal membrane oxygenation (ECMO) treatment, duration of operation, and plasma and red blood cell infusion ratio were collected. The cumulative survival rates of patients at 30, 60, and 180 days after lung transplantation were calculated by Kaplan-Meier method. The univariate and multivariate Cox proportional hazards regression models were used to analyze the effects of donor, recipient, and surgical factors on early survival in donors after lung transplantation. RESULTS: The majority of donors were male (80.6%). There was 63.4% of the donors older than 35 years old, 80.6% of the donors had mechanical ventilation duration less than 10 days, and the median cold ischemia time was 465.00 (369.25, 556.25) minutes. The recipients were mainly males (83.6%). Most of the patients were younger than 65 years old (70.9%). Most of them had no hypertension (75.4%) or diabetes (67.9%). The median mPAP of recipients was 36 (30, 43) mmHg (1 mmHg ≈ 0.133 kPa). There were 73 patients with single lung transplantation (54.5%), and 61 with double lung transplantation (45.5%). The survival rates of 134 IPF patients with PAH at 30, 60, 180 days after lung transplantation were 81.3%, 76.9%, and 67.4%, respectively. Univariate Cox proportional risk regression analysis showed that recipient preoperative use of hormone [hazard ratio (HR) = 2.079, 95% confidence interval (95%CI) was 1.048-4.128], mPAP ≥ 35 mmHg (HR = 2.136, 95%CI was 1.129-4.044), NT-proBNP ≥ 300 ng/L (HR = 2.411, 95%CI was 1.323-4.392), New York Heart Association (NYHA) cardiac function classification III-IV (HR = 3.021, 95%CI was 1.652-5.523) were the risk factors of early postoperative death in patients with IPF complicated with PAH (all P < 0.05). In the multivariable Cox proportional risk regression analysis, recipient preoperative hormone usage (model 1: HR = 2.072, 95%CI was 1.044-4.114, P = 0.037; model 2: HR = 2.098, 95%CI was 1.057-4.165, P = 0.034), NT-proBNP ≥ 300 ng/L (HR = 2.246, 95%CI was 1.225-4.116, P = 0.009) and NYHA cardiac function classification III-IV (HR = 2.771, 95%CI was 1.495-5.134, P = 0.001) were independent risk factors of early postoperative death in patients with IPF. CONCLUSIONS: Preoperative hormone usage, NT-proBNP ≥ 300 ng/L, NYHA cardiac function classification III-IV are independent risk factors for early death in patients with IPF and PAH after lung transplantation. For these patients, attention should be paid to optimize their functional status before operation. Preoperative reduction of receptor hormone usage and improvement of cardiac function can improve the early survival rate of such patients after lung transplantation.

A narrative review of the protective effects of curcumin in treating ischemia-reperfusion injury.

Background and Objective: Ischemia-reperfusion (IR) injury is the cause of morbidity and mortality in a variety of diseases and surgical procedures including organ transplantation surgeries, acute coronary syndrome, strokes, and limb injuries. IR injury causes dysfunction of tissues and organs, and oxidative stress plays an important role in driving this process. Curcumin (CUR), a polyphenolic compound derived from turmeric, protects against IR injury by alleviating oxidative stress, reactive oxygen species (ROS) inflammation, apoptosis, and fibrosis. We review the protective effects of CUR against IR. Methods: We searched PubMed, ScienceDirect, and Web of Science databases using the keywords: ischemic reperfusion, CUR and summarized the results. Key Content and Findings: The effects of CUR during IR have been reported for animal models in vitro and in vivo and the compound has been shown in various organs by suppression of oxidative stress, prevention of inflammation, inhibition of apoptosis and autophagy. CUR with nanocarriers showed many advantages than free CUR in the treatment of IR injury, such as improved bioavailability, sustained-release, better water solubility, better target organ accumulation, improved permeability across the blood-brain-barrier and more effective. Conclusions: Nanotechnology offers significant improvements and promising strategies to improve drug delivery to IR-injured tissues and achieve the desired protective effects. Thus, it is necessary to promote further clinical trials to promote the clinical application of CUR with nanocarriers.

Intracellular Low Iron Exerts Anti-BK Polyomavirus Effect by Inhibiting the Protein Synthesis of Exogenous Genes.

BK polyomavirus (BKPyV) is a small double-stranded DNA virus and ubiquitous human pathogen that particularly affects immunocompromised individuals. Antiviral therapy for BKPyV is urgently needed. Intracellular irons have an important role in many viral infections, yet its contribution to BKPyV and replication has not been explored. In this study, we explored the interaction between BKPyV infection and intracellular iron and the inhibitory effect of iron depletion on BKPyV infection. By creating a low-intracellular-iron environment, we demonstrated that the iron-chelating-induced iron depletion inhibits BKPyV infection in primary renal tubular epithelial cells (RPTECs) and urinary bladder cancer cells (TCCSUP cells). Iron depletion exerts an inhibitory effect after BKPyV enters the nucleus, which might be due to the inhibition of the protein synthesis of exogenous genes in iron-depleted cells. Further exploration of the target proteins of iron-regulating viral infection could potentially be used to develop new strategies for urgently needed anti-BKPyV therapies. IMPORTANCE BKPyV poses a serious threat to the health of immunocompromised patients, and there are currently no curative drugs. Understanding the relationship between the virus and intracellular environment contributes to the discovery of antiviral targets. We demonstrate here that BKPyV is inhibited in cells with a low-iron environment. We also find that iron-chelating-induced iron depletion inhibits viral and exogenous protein synthesis. Further exploration of the target proteins of iron regulation could have great potential in developing new drugs against BKPyV and other viruses.

Determination of PEGylation homogeneity of polyethylene glycol-modified canine uricase.

Polyethylene glycol-modified canine uricase (PEG-UHC) was prepared by modifying the ε-amino group of lysine residues on the canine uricase (UHC) protein to near-saturation with 5 kDa monomethoxyl-polyethylene glycol succinimide (mPEG-SPA-5k). In order to accurately determine the PEGylation uniformity of PEG-UHC, CZE, 3-8% gradient gel SDS-PAGE, and imaging CIEF (iCIEF) analyses were compared. CZE could not effectively separate PEG-UHC proteins with different degrees of modification, 3-8% gradient gel SDS-PAGE could separate PEG-UHC into seven gel bands; however, most of the gel bands were smeared or blurred, and the separation of PEG-UHC samples by iCIEF was significantly better than that by 3-8% gradient gel SDS-PAGE. Under denatured conditions, iCIEF separated 12 pI peaks, and could also accurately quantify the relative monomer PEG-UHC content. More than 85% of the total monomeric PEG-UHC was conjugated with 7-12 PEG molecules; of this 85%, approximately 40% was conjugated with 9-10 PEG molecules. These results demonstrated that iCIEF exhibits good potential for determining the PEGylation homogeneity of PEGylated protein drugs.

Portable integrated digital PCR system for the point-of-care quantification of BK virus from urine samples.

This paper presents a portable integrated digital PCR (PI-dPCR) system with a self-partitioning SlipChip (sp-SlipChip) microfluidic device for the quantitative analysis of BK virus (BKV) viral load directly from raw urine samples. Digital PCR is an accurate nucleic acid quantification method with single-molecule sensitivity, but the complexity of the instrument and the limited integration of the operation workflow greatly limit its application in clinical diagnostics, especially point-of-care testing (PoCT). Our PI-dPCR system has a small footprint, is lightweight, and is fully integrated with the thermal control and fluorescence imaging modules. Unlike the traditional SlipChip device, which requires the precise overlapping of microfeatures on the contacting surfaces to establish the fluidic loading path, this sp-SlipChip device utilizes microchannels with alternating depth and width for fluidic manipulation. This system can quantify BKV directly from raw urine samples with a simple "sample-to-digital-result" operation workflow without complex nucleic acid extraction and purification steps. The current design of the system provides a dynamic range of 3.0 × 104 to 1.5 × 108 copies/mL of BKV DNA in clinical urine samples within 2 h. We tested the system for the quantification of BKV viral load in thirty archived urine samples from kidney transplantation recipients and twelve additional samples from six patients before and after the adjustment of immunosuppressive treatment. This integrated system provides a promising method for both the detection and monitoring of viral infection in a point-of-care setting.

MicroRNA-377 Alleviates Myocardial Injury Induced by Hypoxia/Reoxygenation via Downregulating LILRB2 Expression.

BACKGROUND: miR-377 is closely related to myocardial regeneration. miR-377-adjusted mesenchymal stem cells abducted ischemic cardiac angiogenesis. Nevertheless, there were rarely reports about the impact of miR-377 on myocardial ischemia injury. The purpose of this work is that whether miR-377 can protect against myocardial injury caused by hypoxia/reoxygenation (H/R). METHODS: Gene expression omnibus database (http://www.ncbi.nlm.nih.gov/geo/; no. GSE53211) was utilized to study the differential expression of miR-377 in patients with an acute ST-segment elevation myocardial infarction and healthy controls. The luciferase activity was determined utilizing the dual-luciferase reporter system. Quantitative real-time polymerase chain reaction and Western blotting were used to measure the messenger RNA and protein level. RESULTS: Low expression of miR-377 and high expression of leukocyte immunoglobulin-like receptor B2 (LILRB2) were identified in patients with myocardial infarction from analyzing the Gene Expression Omnibus data set. Besides, miR-377 expression was downregulated in cardiomyocyte exposed to H/R. Additionally, overexpression of miR-377 could visibly improve cardiomyocyte injury by regulating cell activity and apoptosis. CONCLUSIONS: In short, our findings suggested that miR-377/LILRB2 might regard as a hopeful therapeutic target for myocardial ischemic.

Pharmacokinetics of Polyethylene Glycol-Modified Canine Uricase Following Single and Multiple Intravenous Injections in Cynomolgus Monkeys.

BACKGROUND AND OBJECTIVE: Polyethylene glycol-modified canine uricase (PEG-UHC) prepared with a lower-molecular-weight (5 kDa) PEG is used to treat gout. This study investigated the comparative pharmacokinetics of single and multiple doses of PEG-UHC administered intravenously and a single dose of uricase (UHC) administered intravenously in cynomolgus monkeys. METHODS: A noncompartmental model was used to fit the plasma drug concentration-time curve and calculate the pharmacokinetic parameters of PEG-UHC, which were compared with those obtained for UHC at the equivalent dose (2 mg/kg). To study the pharmacokinetics after multiple dose administration, cynomolgus monkeys were administered five intravenous injections of PEG-UHC (0.5 mg/kg), with one injection performed every 15 days. RESULTS: The area under the curve (AUC) and the maximum plasma concentration (Cmax) of PEG-UHC were positively correlated with dose, whereas plasma half-life (t1/2) and clearance (CL) did not change significantly with increasing dose, suggesting that these pharmacokinetic characteristics are linear. Intravenous PEG-UHC exhibited an average t1/2 that was 125.79 times longer and an AUC0-t that was 64.45 times larger than the corresponding values for UHC at the same dose (2 mg/kg), while the CL of PEG-UHC was 1/72.73 times the CL of intravenous UHC. The plasma drug concentration reached a steady state after five injections, and the t1/2 values following the first and last drug administration did not differ significantly. CONCLUSION: Our data show that PEG-UHC is markedly superior to UHC in terms of duration of action, and that the pharmacokinetics of PEG-UHC in cynomolgus monkeys are linear. Sequential administration of PEG-UHC did not accelerate drug clearance. Our findings provide the basis for future clinical studies of PEG-UHC.

Species and sex differences in the blood clearance and immunogenicity of PEGylated uricase: A comparative 26-week toxicity study in rats and monkeys.

Low response rates and high immunogenicity were observed after repeated injections of pegloticase (Krystexxa) into gout patients during clinical trials. However, related research had not been reported in preclinical animal experiments, which has limited the development of this drug. In this study, the toxicity of mPEG-UHC was studied in rats and monkeys over a 26-week period of repeated intravenous dosing. There were no obvious toxic reactions in the tested animals, with the exception of mPEG-UHC blood clearance and immunogenicity. After repeated injections of mPEG-UHC, rapid loss of uricolytic activity (RLA) was not detected in rats, whereas RLA was observed in 44.4% of drug-treated monkeys. In these monkeys, RLA was observed in 11.1% of males and 77.8% of females, and such incidences increased with higher dosing. High titres of anti-uricase IgG antibodies were associated with RLA but did not result in any toxicity. Remission and recurrence of RLA occurred in one female monkey in the high-dose group because of suppressed and altered immune responses in this animal. The predicted incidence of RLA after repeated injections of mPEG-UHC in gout patients may be lower than that of pegloticase. In this study, the no-observed-adverse-effect levels (NOAELs) of mPEG-UHC in rats and monkeys were 32.0 mg/kg and 20.0 mg/kg, respectively. Therefore, the results showed that rats and monkeys could tolerate long-term and high-dose administrations of mPEG-UHC, and mPEG-UHC blood clearance and immunogenicity showed obvious species and sex differences. These findings will provide valuable information to direct the clinical use of mPEG-UHC.

Heterogeneous Klebsiella pneumoniae Co-infections Complicate Personalized Bacteriophage Therapy.

Multidrug-resistant (MDR) organisms have increased worldwide, posing a major challenge for the clinical management of infection. Bacteriophage is expected as potential effective therapeutic agents for difficult-to-treat infections. When performing bacteriophage therapy, the susceptibility of lytic bacteriophage to the target bacteria is selected by laboratory isolate from patients. The presence of a subpopulation in a main population of tested cells, coupled with the rapid development of phage-resistant populations, will make bacteriophage therapy ineffective. We aimed to treat a man with multifocal urinary tract infections of MDR Klebsiella pneumoniae by phage therapy. However, the presence of polyclonal co-infectious cells in his renal pelvis and bladder led to the failure of three consecutive phage therapies. After analysis, the patient was performed with percutaneous nephrostomy (PCN). A cocktail of bacteriophages was selected for activity against all 21 heterogeneous isolates and irrigated simultaneously via the kidney and bladder to eradicate multifocal colonization, combined with antibiotic treatment. Finally, the patient recovered with an obviously improved bladder. The success of this case provides valuable treatment ideas and solutions for phage treatment of complex infections. Clinical Trial Registration: www.chictr.org.cn, identifier ChiCTR1900020989.

IL-8 and IP-10 expression from human bronchial epithelial cells BEAS-2B are promoted by Streptococcus pneumoniae endopeptidase O (PepO).

BACKGROUND: The bronchial epithelium serves as the first defendant line of host against respiratory inhaled pathogens, mainly through releasing chemokines (e.g. interleukin-8 (IL-8), interferon-induced protein 10 (IP-10) etc.) responsible for neutrophil or lymphocyte recruitment to promote the clearance of inhaled pathogens including Streptococcus pneumoniae (S. pneumoniae). Previous studies have shown that IL-8 expression is induced by pneumococcal virulence factors (e.g. pneumolysin, peptidoglycan-polysaccharides, pneumococcal surface protein A (PspA) etc.), which contributes to the pathogenesis of pneumonia. Whether other pneumococcal virulence factors are involved in inducing chemokines expression in epithelium is still unknown. RESULTS: We studied the effect of PepO, a widely expressed and newly discovered pneumococcal virulence protein, on the release of proinflammatory cytokines, IL-8 and IP-10, from human bronchial epithelial cell line BEAS-2B and identified the relevant signaling pathways. Incubation of BEAS-2B with PepO resulted in increased synthesis and release of IL-8 and IP-10 in a dose and time independent manner. We also detected the increased and sustained expression of TLR2 and TLR4 transcripts in BEAS-2B stimulated by PepO. PepO activation leaded to the phosphorylation of MAPKs, Akt and p65. Pharmacologic inhibitors of MAPKs, PI3K and IκB-α phosphorylation attenuated IL-8 release, while IP-10 production was just suppressed by inhibitors of IκB-α phosphorylation, PI3K and P38 MAPK. CONCLUSION: These results suggest that PepO enhances IL-8 and IP-10 production in BEAS-2B in a MAPKs-PI3K/Akt-p65 dependent manner, which may play critical roles in the pathogenesis of pneumonia.

13-Methyltetradecanoic acid mitigates cerebral ischemia/reperfusion injury.

13-Methyltetradecanoic acid can stabilize cell membrane and have anti-inflammatory, antioxidant and anti-apoptotic effects. Previous studies mainly focused on peripheral nerve injury, but seldom on the central nervous system. We investigated whether these properties of 13-methyltetradecanoic acid have a neuroprotective effect on focal cerebral ischemia/reperfusion injury, and detected the expression of basic fibroblast growth factor and vascular endothelial growth factor. This study established rat models of middle cerebral artery occlusion/reperfusion injury by ischemia for 2 hours and reperfusion for 24 hours. At the beginning of reperfusion, 13-methyltetradecanoic acid 10, 40 or 80 mg/kg was injected into the tail vein. Results found that various doses of 13-methyltetradecanoic acid effectively reduced infarct volume, mitigate cerebral edema, and increased the mRNA and protein expression of basic fibroblast growth factor and vascular endothelial growth factor at 24 hours of reperfusion. The effect was most significant in the 13-methyltetradecanoic acid 40 and 80 mg/kg groups. The findings suggest that 13-methyltetradecanoic acid can relieve focal ischemia/reperfusion injury immediately after reperfusion, stimulate the upregulation of basic fibroblast growth factor and vascular endothelial growth factor to exert neuroprotective effects.

Characterization, efficacy, pharmacokinetics, and biodistribution of 5kDa mPEG modified tetrameric canine uricase variant.

PEGylated uricase is a promising anti-gout drug, but the only commercially marketed 10kDa mPEG modified porcine-like uricase (Pegloticase) can only be used for intravenous infusion. In this study, tetrameric canine uricase variant was modified by covalent conjugation of all accessible ɛ amino sites of lysine residues with a smaller 5kDa mPEG (mPEG-UHC). The average modification degree and PEGylation homogeneity were evaluated. Approximately 9.4 5 kDa mPEG chains were coupled to each monomeric uricase and the main conjugates contained 7-11 mPEG chains per subunit. mPEG-UHC showed significantly therapeutic or preventive effect on uric acid nephropathy and acute urate arthritis based on three different animal models. The clearance rate from an intravenous injection of mPEG-UHC varied significantly between species, at 2.61 mL/h/kg for rats and 0.21 mL/h/kg for monkeys. The long elimination half-life of mPEG-UHC in non-human primate (191.48 h, intravenous injection) indicated the long-term effects in humans. Moreover, the acceptable bioavailability of mPEG-UHC after subcutaneous administration in monkeys (94.21%) suggested that subcutaneous injection may be regarded as a candidate administration route in clinical trails. Non-specific tissue distribution was observed after administration of (125)I-labeled mPEG-UHC in rats, and elimination by the kidneys into the urine is the primary excretion route.