COMPARISON AMONG PRESEPSIN, PROCALCITONIN, AND C-REACTIVE PROTEIN IN PREDICTING BLOOD CULTURE POSITIVITY AND PATHOGEN IN SEPSIS PATIENTS.

ABSTRACT: Background: Sepsis is caused by the invasion of the bloodstream by microorganisms from local sites of infection, leading to high mortality. This study aimed to compare the predictive ability of the biomarkers presepsin, procalcitonin (PCT), and C-reactive protein for bacteraemia. Methods: In this retrospective, multicentre study, a dataset of patients with sepsis who were prospectively enrolled between November 2017 and June 2021 was analyzed. The performances of the biomarkers for predicting positive blood cultures and infection with specific pathogens were assessed by the areas under the receiver operating characteristic curves (AUCs). The independent effects of the pathogen and foci of infection on presepsin and PCT levels were assessed by linear logistic regression models. Results: A total of 577 patients with 170 positive blood cultures (29.5%) were enrolled. The AUC achieved using PCT levels (0.856) was significantly higher than that achieved using presepsin (0.786, P = 0.0200) and C-reactive protein (0.550, P < 0.0001) levels in predicting bacteraemia. The combined analysis of PCT and presepsin levels led to a significantly higher AUC than the analysis of PCT levels alone for predicting blood culture positivity (0.877 vs. 0.856, P = 0.0344) and gram-negative bacteraemia (0.900 vs. 0.875, P = 0.0216). In a linear regression model, the elevated concentrations of presepsin and PCT were both independently related to Escherichia coli , Klebsiella species, Pseudomonas species, and Streptococcus species infections and Sequential Organ Failure Assessment score. Presepsin levels were also associated with Acinetobacter species and abdominal infection, and PCT levels were positively associated with other Enterobacteriaceae and negatively associated with respiratory infection. Combined analysis of presepsin and PCT levels provided a high sensitivity and specificity in identifying E. coli or Klebsiella species infection. Conclusions: Presepsin and PCT were promising markers for predicting bacteraemia and common pathogens at the time of sepsis onset with a synergistic effect.

Simultaneous Improvement in the Thermostability and Catalytic Activity of Epoxidase Lsd18 for the Synthesis of Lasalocid A.

Enzymes used in the synthesis of natural products are potent catalysts, capable of efficient and stereoselective chemical transformations. Lsd18 catalyzes two sequential epoxidations during the biosynthesis of lasalocid A, a polyether polyketide natural product. We performed protein engineering on Lsd18 to improve its thermostability and catalytic activity. Utilizing structure-guided methods of FoldX and Rosetta-ddG, we designed 15 mutants of Lsd18. Screening of these mutants using thermal shift assay identified stabilized variants Lsd18-T189M, Lsd18-S195M, and the double mutant Lsd18-T189M-S195M. Trypsin digestion, molecular dynamic simulation, circular dichroism (CD) spectroscopy, and X-ray crystallography provided insights into the molecular basis for the improved enzyme properties. Notably, enhanced hydrophobic interaction within the enzyme core and interaction of the protein with the FAD cofactor appear to be responsible for its better thermostability.

Acupuncture Relieves Cervical Spondylosis Radiculopathy by Regulating Spinal Microglia Activation Through MAPK Signaling Pathway in Rats.

Purpose: Local acupuncture has been found to have a good analgesic effect in rats with cervical spondylosis radiculopathy (CSR), but it lacks a regulatory effect on traditional Chinese medicine syndrome types of CSR. We proposed "Invigorating Qi and activating Blood" (IQAB) acupuncture, compared with Fenbid, and local electroacupuncture (LEA), to observe whether it has advantages in the protection of the CSR rat model and to elucidate its mechanism through the MAPK (mitogen-activated protein kinase) signaling pathway. Materials and Methods: Male Sprague-Dawley rats were randomly divided into six groups: control, sham, model, Fenbid, LEA, and IQAB. The CSR model was induced by inserting nylon sutures to compress the C4-T1 nerve root. The Fenbid group was treated with ibuprofen sustained-release capsules (15 mg/kg·d, ig). The LEA group received electroacupuncture at both C5 and C7 EX-B2 once a day. The IQAB group received acupuncture at both ST36 and BL17 based on the LEA group's intervention. Mechanical allodynia and gait, morphological changes in the spinal cord, IL-6 and TNF-α levels, MAPKs phosphorylation ratio, monocyte chemoattractant protein-1 (MCP-1) levels in the spinal cord, and the expression of p-p38 in the spinal cord and its colocalization with neurons and glial cell activation markers were detected. Results: Mechanical allodynia, gait disorder, edema, reduced Nissl-positive cell numbers, and increased IL-6 and TNF-α levels in the spinal cord were observed in CSR rats. IQAB significantly alleviated these changes, and the effects were generally comparable to those of Fenbid. Meanwhile, the phosphorylation ratios of p38 and extracellular regulated protein kinase (ERK), co-expression of p-p38 with neuron/microglia, and MCP-1 levels in the spinal cord were markedly down-regulated by IQAB compared with those in CSR model rats. Conclusion: IQAB reduced p38-activation-related microglia activation and MCP-1 levels, thus alleviating pathological changes, inflammation levels in the local spinal cord, and pain behavior of CSR.

Triepoxide formation by a flavin-dependent monooxygenase in monensin biosynthesis.

Monensin A is a prototypical natural polyether polyketide antibiotic. It acts by binding a metal cation and facilitating its transport across the cell membrane. Biosynthesis of monensin A involves construction of a polyene polyketide backbone, subsequent epoxidation of the alkenes, and, lastly, formation of cyclic ethers via epoxide-opening cyclization. MonCI, a flavin-dependent monooxygenase, is thought to transform all three alkenes in the intermediate polyketide premonensin A into epoxides. Our crystallographic study has revealed that MonCI's exquisite stereocontrol is due to the preorganization of the active site residues which allows only one specific face of the alkene to approach the reactive C(4a)-hydroperoxyflavin moiety. Furthermore, MonCI has an unusually large substrate-binding cavity that can accommodate premonensin A in an extended or folded conformation which allows any of the three alkenes to be placed next to C(4a)-hydroperoxyflavin. MonCI, with its ability to perform multiple epoxidations on the same substrate in a stereospecific manner, demonstrates the extraordinary versatility of the flavin-dependent monooxygenase family of enzymes.

CLINICAL CHARACTERISTICS AND PREDICTORS OF MORTALITY DIFFER BETWEEN PULMONARY AND ABDOMINAL SEPSIS.

ABSTRACT: Background: Pulmonary sepsis and abdominal sepsis have pathophysiologically distinct phenotypes. This study aimed to compare their clinical characteristics and predictors of mortality. Methods: In this multicenter retrospective trial, 1,359 adult patients who fulfilled the Sepsis-3 criteria were enrolled and classified into the pulmonary sepsis or abdominal sepsis groups. Plasma presepsin was measured, and the scores of Acute Physiology and Chronic Health Evaluation (APACHE) II, Mortality in Emergency Department Sepsis (MEDS), and Simplified Acute Physiology Score (SAPS) II were calculated at enrollment. Data on 28-day mortality were collected for all patients. Results: Compared with patients with abdominal sepsis (n = 464), patients with pulmonary sepsis (n = 895) had higher 28-day mortality rate, illness severity scores, incidence of shock and acute kidney injury, and hospitalization costs. Lactate level and APACHE II and MEDS scores were independently associated with 28-day mortality in both sepsis types. Independent predictors of 28-day mortality included Pa o2 /F io2 ratio (hazard ratio [HR], 0.998; P < 0.001) and acute kidney injury (HR, 1.312; P = 0.039) in pulmonary sepsis, and SAPS II (HR, 1.037; P = 0.017) in abdominal sepsis. A model that combined APACHE II score, lactate, and MEDS score or SAPS II score had the best area under the receiver operating characteristic curve in predicting mortality in patients with pulmonary sepsis or abdominal sepsis, respectively. Interaction term analysis confirmed the association between 28-day mortality and lactate, APACHE II score, MEDS score, SAPS II score, and shock according to the sepsis subgroups. The mortality of patients with pulmonary sepsis was higher than that of patients with abdominal sepsis among patients without shock (32.9% vs. 8.8%; P < 0.001) but not among patients with shock (63.7 vs. 48.4%; P = 0.118). Conclusions: Patients with pulmonary sepsis had higher 28-day mortality than patients with abdominal sepsis. The study identified sepsis subgroup-specific mortality predictors. Shock had a larger effect on mortality in patients with abdominal sepsis than in those with pulmonary sepsis.

Predictive value of presepsin and acylcarnitines for severity and biliary drainage in acute cholangitis.

BACKGROUND: Bacteremia, which is a major cause of mortality in patients with acute cholangitis, induces hyperactive immune response and mitochondrial dysfunction. Presepsin is responsible for pathogen recognition by innate immunity. Acylcarnitines are established mitochondrial biomarkers. AIM: To clarify the early predictive value of presepsin and acylcarnitines as biomarkers of severity of acute cholangitis and the need for biliary drainage. METHODS: Of 280 patients with acute cholangitis were included and the severity was stratified according to the Tokyo Guidelines 2018. Blood presepsin and plasma acylcarnitines were tested at enrollment by chemiluminescent enzyme immunoassay and ultra-high-performance liquid chromatography-mass spectrometry, respectively. RESULTS: The concentrations of presepsin, procalcitonin, short- and medium-chain acylcarnitines increased, while long-chain acylcarnitines decreased with the severity of acute cholangitis. The areas under the receiver operating characteristic curves (AUC) of presepsin for diagnosing moderate/severe and severe cholangitis (0.823 and 0.801, respectively) were greater than those of conventional markers. The combination of presepsin, direct bilirubin, alanine aminotransferase, temperature, and butyryl-L-carnitine showed good predictive ability for biliary drainage (AUC: 0.723). Presepsin, procalcitonin, acetyl-L-carnitine, hydroxydodecenoyl-L-carnitine, and temperature were independent predictors of bloodstream infection. After adjusting for severity classification, acetyl-L-carnitine was the only acylcarnitine independently associated with 28-d mortality (hazard ratio 14.396; P < 0.001) (AUC: 0.880). Presepsin concentration showed positive correlation with direct bilirubin or acetyl-L-carnitine. CONCLUSION: Presepsin could serve as a specific biomarker to predict the severity of acute cholangitis and need for biliary drainage. Acetyl-L-carnitine is a potential prognostic factor for patients with acute cholangitis. Innate immune response was associated with mitochondrial metabolic dysfunction in acute cholangitis.

Identification of gut microbes associated with feed efficiency by daily-phase feeding strategy in growing-finishing pigs.

Feed efficiency is one of the most important issues for sustainable pig production. Daily-phase feeding (DPF) is a form of precision feeding that could improve feed efficiency in pigs. Gut microbiota can regulate host nutrient digestion, absorption, and metabolism. However, which key microbes may play a vital role in improving the feed efficiency during DPF remains unclear. In the present study, we used a DPF program compared to a three-phase feeding (TPF) program in growing-finishing pigs to investigate the effects of gut microbiota on feed efficiency. A total of 204 Landrace × Yorkshire pigs (75 d) were randomly assigned into 2 treatments. Each treatment was replicated 8 times with 13 to 15 pigs per replicate pen. Pigs in the TPF group were fed with a commercial feeding program that supplied fixed feed for phases I, II, and III, starting at 81, 101, and 132 d of age, respectively, and pigs in the DPF group were fed a blend of adjacent phase feed from 81 to 155 d at a gradual daily ratio and phase III feed from 155 to 180 d of age. Daily feed intake and body weight were recorded by a computerized device in the feeders. Feces and blood samples were collected from 1 pig per replicate at 155 and 180 d of age. The results showed that the DPF program remarkably improved the feed efficiency at 155 d (P < 0.001) and 180 d of age (P < 0.001), with a significant reduction of the intake of crude protein (P < 0.01), net energy (P < 0.001), crude fiber (P < 0.001), ether extract (P < 0.01), and ash (P < 0.001). The daily-phase feeding program increased the abundance of Prevotella copri (P < 0.05) and Paraprevotella clara (P < 0.05), while it decreased the abundance of Ocilibacter (P < 0.05) at 155 d of age. The results of correlation analysis indicated that the differentially abundant microbiota communities were closely associated with 20 metabolites which enriched amino acid and phenylalanine metabolism. Our results suggest that 2 key microbes may contribute to feed efficiency during daily-phase feeding strategies in pigs.

Dynamic blood presepsin levels are associated with severity and outcome of acute pancreatitis: A prospective cohort study.

BACKGROUND: Acute pancreatitis (AP) is an inflammatory disorder of the pancreas with an unpredictable course of illness. A major challenge of AP is the early identification of patients at high-risk for organ failure and death. However, scoring systems are complicated and time consuming, and the predictive values for the clinical course are vague. AIM: To determine whether the dynamic changes in presepsin levels can be used to evaluate the severity of disease and outcome of AP. METHODS: In this multicentric cohort study, 133 patients with AP were included. Clinical severity was dynamically evaluated using the 2012 revised Atlanta Classification. Blood presepsin levels were measured at days 1, 3, 5 and 7 after admission by chemiluminescent enzyme immunoassay. RESULTS: The median concentration of presepsin increased and the clearance rate of presepsin decreased with disease severity and organ failure in AP patients. The presepsin levels on days 3, 5 and 7 were independent predictors of moderately severe and severe AP with time-specific area under the curve (AUC) values of 0.827, 0.848 and 0.867, respectively. The presepsin levels positively correlated with bedside index of severity in AP, Ranson, acute physiology and chronic health evaluation II, computed tomography severity index and Marshall scores. Presepsin levels on days 3, 5 and 7 were independent predictors of 28-d mortality of AP patients with AUC values of 0.781, 0.846 and 0.843, respectively. CONCLUSION: Blood presepsin levels within 7 d of admission were associated with and may be useful to dynamically predict the severity of disease course and 28-d mortality in AP patients.

Alternative splicing analysis showed the splicing factor polypyrimidine tract-binding protein 1 as a potential target in acute myeloid leukemia therapy.

Alternative splicing (AS) is a universal post-transcriptional regulation process in cells, and increasing evidences have validated its crucial role in tumors. We collected AS event, gene expression, and clinical data of 178 AML patients from The Cancer Genome Atlas (TCGA) project. More than 1,000 AS events were found associated with overall survival (OS), and alternate promoter (AP) events were the most significant. The expression of the KIAA0930 transcript was the most significantly different AS event selected from AP events and significantly correlated with the expression of the splicing factor (SF) polypyrimidine tract-binding protein 1 (PTBP1). Then, the roles of PTBP1 on AS of the KIAA0930 and the proliferation of AML cells were confirmed. KIAA0930 variant 1 (KIAA0930-1) was upregulated and variant 2 (KIAA0930-2) downregulated with knockdown PTBP1 expression of AML cells by specific shRNA. A low level of PTBP1 can decrease the proliferation ability of AML cells. In conclusion, the results showed that PTBP1 might be a potential target for AML therapy.

Increasing angiotensin-converting enzyme (ACE) 2/ACE axes ratio alleviates early pulmonary vascular remodeling in a porcine model of acute pulmonary embolism with cardiac arrest.

BACKGROUND: Acute pulmonary embolism (APE) with cardiac arrest (CA) is characterized by high mortality in emergency due to pulmonary arterial hypertension (PAH). This study aims to determine whether early pulmonary artery remodeling occurs in PAH caused by massive APE with CA and the protective effects of increasing angiotensin-converting enzyme (ACE) 2-angiotensin (Ang) (1-7)-Mas receptor axis and ACE-Ang II-Ang II type 1 receptor (AT1) axis (ACE2/ACE axes) ratio on pulmonary artery lesion after return of spontaneous circulation (ROSC). METHODS: To establish a porcine massive APE with CA model, autologous thrombus was injected into the external jugular vein until mean arterial pressure dropped below 30 mmHg (1 mmHg=0.133 kPa). Cardiopulmonary resuscitation and thrombolysis were delivered to regain spontaneous circulation. Pigs were divided into four groups of five pigs each: control group, APE-CA group, ROSC-saline group, and ROSC-captopril group, to examine the endothelial pathological changes and expression of ACE2/ACE axes in pulmonary artery with or without captopril. RESULTS: Histological analysis of samples from the APE-CA and ROSC-saline groups showed that pulmonary arterioles were almost completely occluded by accumulated endothelial cells. Western blotting analysis revealed a decrease in the pulmonary arterial ACE2/ACE axes ratio and increases in angiopoietin-2/angiopoietin-1 ratio and expression of vascular endothelial growth factor (VEGF) in the APE-CA group compared with the control group. Captopril significantly suppressed the activation of angiopoietin-2/angiopoietin-1 and VEGF in plexiform lesions formed by proliferative endothelial cells after ROSC. Captopril also alleviated endothelial cell apoptosis by increasing the B-cell lymphoma-2 (Bcl-2)/Bcl-2-associated X (Bax) ratio and decreasing cleaved caspase-3 expression. CONCLUSION: Increasing the ACE2/ACE axes ratio may ameliorate pulmonary arterial remodeling by inhibiting the apoptosis and proliferation of endothelial cells after ROSC induced by APE.

Acute pancreatitis in pregnancy: a 10-year, multi-center, retrospective study in Beijing.

OBJECTIVE: Acute pancreatitis in pregnancy (APIP) is a rare and serious complication during pregnancy. It has acute onset and is difficult to diagnose and treat. The aim of the present study was to describe the etiology, clinical manifestations, and maternofetal outcomes of APIP. METHODS: We retrospectively reviewed 32 pregnant women who were treated at three tertiary care hospitals in Beijing, China. The correlation between the causes of APIP, severity, laboratory indices, and outcomes was analyzed. RESULTS: The most common causes of APIP were hypertriglyceridemia (56.2%,18/32) and gallstones (28.1%, 9/32). Hypertriglyceridemia-induced APIP was associated with a higher rate of severe acute pancreatitis (P = 0.025). Serum level of triglycerides showed a positive correlation with the severity of APIP (P = 0.039). The most frequent presentation of APIP was abdominal pain (93.7%, 30/32). There were no maternal or fetal deaths in our study. Apgar scores at 1 min, 5 min, and 10 min of the premature neonates was correlated with the severity of APIP of the mother (P = 0.022; 0.002; 0.002). CONCLUSION: High level of triglycerides may serve as a useful marker of the severity of APIP. The severity of APIP was associated with higher risk of neonate asphyxia. Appropriate timing of termination of pregnancy is a key imperative for APIP patients.

Vitamin D Attenuates Airway Inflammation in Asthmatic Guinea Pigs Using Mammalian Target of Rapamycin-Mediated Autophagy.

The purpose of this experiment is to find out the function of Vitamin D (VD) in airway inflammation in asthmatic guinea pigs by regulating mammalian target of rapamycin (mTOR)-mediated autophagy. A total of 40 male guinea pigs were randomly assigned into the Con group, the ovalbumin (OVA)-sensitized group, the VD group, the VD + dimethyl sulfoxide group, and the VD + rapamycin (mTOR inhibitor) group. Then, serum from all groups was harvested for the measurement of immunoglobulin E (IgE), interleukin (IL)-4, and IL-5 levels. Next, bronchoalveolar lavage fluid was collected for cell counting. Moreover, lung tissues were extracted to assess levels of p-mTOR and autophagy factors (LC3B, Beclin1, Atg5, and P62). Compared with the Con group, the OVA group showed elevated levels of IgE, IL-4, and IL-5, increased contents of eosinophils, neutrophil, and lymphocytes, and declined monocytes. And the VD group improved inflammatory reactions in the guinea pigs. Besides, the OVA group showed lower levels of p-mTOR and P62 and higher autophagy levels than the Con group, while the VD group had opposite results. Rapamycin annulled the suppressive role of VD to airway inflammation in asthmatic guinea pigs. VD might inhibit OVA-induced airway inflammation by inducing mTOR activation and downregulating autophagy in asthmatic guinea pigs.

Potential Value of Presepsin Guidance in Shortening Antibiotic Therapy in Septic Patients: a Multicenter, Prospective Cohort Trial.

INTRODUCTION: Long-term use of antibiotics for septic patients leads to bacterial resistance, increased mortality, and hospital stay. In this study, we investigated an emerging biomarker presepsin-guided strategy, which can be used to evaluate the shortening of antibiotic treatment in patients with sepsis without risking a worse outcome. METHODS: In this multicenter prospective cohort trial, patients were assigned to the presepsin or control groups. In the presepsin group, antibiotics were ceased based on predefined cut-off ranges of presepsin concentrations. The control group stopped antibiotics according to international guidelines. The primary endpoints were the number of days without antibiotics within 28 days and mortality at 28 and 90 days. Secondary endpoints were the percentage of patients with a recurrent infection, length of stay in ICU and hospital, hospitalization costs, days of first episode of antibiotic treatment, percentage of antibiotic administration and multidrug-resistant bacteria, and SOFA score. RESULTS: Overall, 656 out of an initial 708 patients were eligible and assigned to the presepsin group (n = 327) or the control group (n = 329). Patients in the presepsin group had significantly more days without antibiotics than those in the control group (14.54 days [SD 9.01] vs. 11.01 days [SD 7.73]; P < 0.001). Mortality in the presepsin group showed no difference to that in the control group at days 28 (17.7% vs. 18.2%; P = 0.868) and 90 (19.9% vs. 19.5%; P = 0.891). Patients in the presepsin group had a significantly shorter mean length of stay in the hospital and lower hospitalization costs than control subjects. There were no differences in the rate of recurrent infection and multidrug-resistant bacteria and the SOFA score tendency between the two groups. CONCLUSIONS: Presepsin guidance has potential to shorten the duration of antibiotic treatment in patients with sepsis without risking worse outcomes of death, recurrent infection, and aggravation of organ failure. TRIAL REGISTRATION: ChiCTR, ChiCTR1900024391. Registered 9 July 2019-Retrospectively registered, http://www.chictr.org.cn.

Vitamin D has an effect on airway inflammation and Th17/Treg balance in asthmatic mice.

Asthma is regarded as a chronic inflammation of the airway. Research has highlighted the significance of Vitamin D in asthma. This study explored the mechanism of vitamin D on asthma. The asthma mouse model was established by ovalbumin (OVA) sensitization and treated with vitamin D (50 or 100 ng/ml). The morphological changes of the airway were observed by HE staining. The serum IgE contents and MDA, ROS, and SOD expressions in the bronchoalveolar lavage fluid (BALF) were detected by ELISA. The Th17 and Treg cells were detected using flow cytometry. The RORγt and Foxp 3 expressions were detected by Reverse transcription quantitative polymerase chain reaction (RT-qPCR). IL-17, IL-10, and TGF-ß1 expressions were detected using ELISA. The NF-κB pathway was blocked using the NF-κB pathway inhibitor, Andrographolide sulfonate. The NF-κB pathway-related indexes were detected by western blotting. After blockade of the NF-κB pathway, the IL-17, IL-10, and TGF-G1 expressions were detected. OVA-sensitized asthma induced airway remodeling and elevated IgE content in mice, which was downregulated after vitamin D treatment. MDA and ROS were upregulated and SOD was downregulated in asthmatic mice, while vitamin D inverted the changes. Th17/Treg ratio was imbalanced, RORγt and IL-17 were upregulated, and Foxp 3, IL-10, and TGF-ß1 were downregulated after OVA sensitization, while vitamin D treatment inverted these changes and inhibited the NF-κB-p65 phosphorylation level. After blockade of the NF-κB pathway, IL-17 was downregulated and IL-10 and TGF-ß1 were upregulated. In conclusion, vitamin D rectified the Th17/Treg balance and alleviated airway inflammation by inhibiting the NF-κB pathway in asthmatic mice.

Alterations of Oral Microbiota in Chinese Patients With Esophageal Cancer.

Emerging evidence supports that oral microbiota are associated with health and diseases of the esophagus. How oral microbiota change in Chinese patients with esophageal cancer (EC) is unknown, neither is their biomarker role. For an objective to understand alterations of oral microbiota in Chinese EC patients, we conducted a case-control study including saliva samples from 39 EC patients and 51 healthy volunteers. 16S rDNA genes of V3-V4 variable regions were sequenced to identify taxon. Relationship between oral flora and disease was analyzed according to alpha diversity and beta diversity. Resultantly, the Shannon index (p = 0.2) and the Simpson diversity index (p = 0.071) were not significant between the two groups. Yet we still found several species different in abundance between the two groups. For the EC group, the most significantly increased taxa were Firmicutes, Negativicutes, Selenomonadales, Prevotellaceae, Prevotella, and Veillonellaceae, while the most significantly decreased taxa were Proteobacteria, Betaproteobacteria, Neisseriales, Neisseriaceae, and Neisseria. In conclusion, there are significant alterations in abundance of some oral microbiomes between the EC patients and the healthy controls in the studied Chinese participants, which may be meaningful for predicting the development of EC, and the potential roles of these species in EC development deserve further studies.

Osteochondral repair using scaffolds with gradient pore sizes constructed with silk fibroin, chitosan, and nano-hydroxyapatite.

BACKGROUND: One of the main problems associated with the development of osteochondral reparative materials is that the accurate imitation of the structure of the natural osteochondral tissue and fabrication of a suitable scaffold material for osteochondral repair are difficult. The long-term outcomes of single- or bilayered scaffolds are often unsatisfactory because of the absence of a progressive osteochondral structure. Therefore, only scaffolds with gradient pore sizes are suitable for osteochondral repair to achieve better proliferation and differentiation of the stem cells into osteochondral tissues to complete the repair of defects. METHODS: A silk fibroin (SF) solution, chitosan (CS) solution, and nano-hydroxyapatite (nHA) suspension were mixed at the same weight fraction to obtain osteochondral scaffolds with gradient pore diameters by centrifugation, freeze-drying, and chemical cross-linking. RESULTS: The scaffolds prepared in this study are confirmed to have a progressive structure starting from the cartilage layer to bone layer, similar to that of the normal osteochondral tissues. The prepared scaffolds are cylindrical in shape and have high internal porosity. The structure consists of regular and highly interconnected pores with a progressively increasing pore distribution as well as a progressively changing pore diameter. The scaffold strongly absorbs water, and has a suitable degradation rate, sufficient space for cell growth and proliferation, and good resistance to compression. Thus, the scaffold can provide sufficient nutrients and space for cell growth, proliferation, and migration. Further, bone marrow mesenchymal stem cells seeded onto the scaffold closely attach to the scaffold and stably grow and proliferate, indicating that the scaffold has good biocompatibility with no cytotoxicity. CONCLUSION: In brief, the physical properties and biocompatibility of our scaffolds fully comply with the requirements of scaffold materials required for osteochondral tissue engineering, and they are expected to become a new type of scaffolds with gradient pore sizes for osteochondral repair.

Immune regulation mechanism of vitamin D level and IL-17/IL-17R pathway in Crohn's disease.

Immune regulation mechanism of vitamin D level and interleukin (IL)-17/IL-17 receptor (IL-17R) pathway in Crohn's disease was studied. Of 40 clean mature healthy rats, 10 rats were used as control group based on random number table, the remaining 30 rats to establish Crohn's disease rat models. After successful modeling, 30 rats were divided into model group, low-dose group and high-dose group with random number table. On the 1st day after modeling, rats in low-dose group were given a single dose of 1,750 IU of vitamin D, and rats in high-dose group a single dose of 7,500 IU of vitamin D. Changes in the condition of rats after modeling were observed and scored. Enzyme-linked immunosorbent assay was used for detecting IL-12, IL-17 and CXCL11 levels, western blotting for detecting IL-17R level, and flow cytometry for detecting Th1 cell and Th17 cell levels in the lamina propria of colon mucosa. Disease activity index scores were significantly lower in low-dose group and high-dose group of rats than those in model group (P<0.05). Those were significantly lower in high-dose group of rats than those in low-dose group (P<0.05). IL-17 and IL-17R levels were significantly lower in high-dose group of rats than those in low-dose group (P<0.05). Th1 cell level was significantly higher in high-dose group of rats than that in low-dose group (P<0.05), but Th17 cell level was lower than that in low-dose group (P<0.05). IL-12 levels were significantly higher in model group, low-dose group and highdose group of rats than those in control group (P<0.05). CXCL11 levels were significantly lower in model group, low-dose group and high-dose group of rats than those in control group (P<0.05). Vitamin D can effectively treat Crohn's disease, which may improve the chemotaxis and differentiation of Th1 cells by inhibiting IL-17/IL-17R pathway, thereby improving immune function and reducing the severity of disease.

Imbalance of angiotensin-converting enzymes affects myocardial apoptosis during cardiac arrest induced by acute pulmonary embolism in a porcine model.

Acute pulmonary embolism (APE) with cardiac arrest (CA) is associated with a high mortality rate. Even upon return of the spontaneous circulation (ROSC), APE­CA survivors are prone to myocardial cell apoptosis, a key cellular mechanism that induces heart failure. A recent study by our group discovered a post­resuscitation imbalance in the serum angiotensin­converting enzyme (ACE)2/ACE axis of the renin­angiotensin system (RAS), as well as regressive cardiac function in a porcine model of APE­CA. However, it has remained elusive how this imbalance in the ACE2/ACE axis affects myocardial cell apoptosis. In the present study, western blot and immunohistochemical analyses demonstrated that the RAS was only activated in the left myocardium, as evidenced by a decreased ACE2/ACE ratio following APE­CA and ROSC, but not the right myocardium. Ultrastructural analysis confirmed myocardial apoptosis in the left and right myocardium. Furthermore, B­cell lymphoma 2 (Bcl­2)­associated X protein (Bax) and caspase­3 levels were elevated and Bcl­2 levels were decreased in the left myocardium following APE­CA and ROSC. Treatment with the ACE inhibitor captopril for 30 min after initiation of ROSC prevented the increase in Bax and the decrease in Bcl­2 in the left myocardium compared with that in saline­treated pigs. Captopril also inhibited the activation of extracellular signal­regulated kinase (ERK)1/2 in the left myocardium. The results of the present study suggest that an imbalance in the ACE2/ACE axis has an important role in myocardial apoptosis following APE­CA, which may be attributed to decreased ERK1/2 activation. In addition, it was indicated that captopril prevents apoptosis in the left myocardium after ROSC.

Angiotensin­(1­7) prevents lipopolysaccharide­induced hepatocellular inflammatory response by inhibiting the p38MAPK/AP­1 signaling pathway.

The pathological mechanism of lipopolysaccharide (LPS)­induced liver injury involves a number of inflammatory mediators and cytokines. Angiotensin (Ang)­(1­7), a ligand for the proto­oncogene Mas (Mas) receptor, antagonizes the actions of Ang II in the renin angiotensin system and exerts an anti­inflammatory effect on LPS­induced macrophages. The present study investigated the potential role of Ang­(1­7) in the regulation of inflammatory responses in LPS­induced hepatocytes using the rat liver BRL cell line. The results of the present study demonstrated that the inflammatory mediator, tumor necrosis factor (TNF)­α, its upstream transcriptional regulatory factor activator protein (AP)­1 and p38 mitogen activated protein kinase (MAPK) which were detected by reverse transcription­quantitative polymerase chain reaction and western blotting were upregulated in LPS­induced hepatic cells in a time­dependent manner, peaking 12 h following LPS stimulation. By contrast, treatment with Ang­(1­7) significantly attenuated the expression of TNF­α, AP­1 and p38MAPK in a concentration­dependent manner. The anti­inflammatory effect of Ang­(1­7) was reversed by the Mas receptor selective antagonist, A779, in BRL cells. Furthermore, the p38MAPK inhibitor, SB 203580, abolished the protective effects of Ang­(1­7), suggesting the involvement of the p38MAPK pathway in the anti­inflammatory activity of Ang­(1­7). The results of the present study indicated that Ang­(1­7) may serve an anti­inflammatory role in LPS­induced hepatocyte injury via the regulation of the p38MAPK/AP­1 signaling pathway.