Peritonitis Model Research Articles

Effects of ceftriaxone, black seed oil (Nigella sativa), and their combination on interleukin-10 expression in a Wistar rat peritonitis model

Effects of ceftriaxone, black seed oil (Nigella sativa), and their combination on interleukin-10 expression in a Wistar rat peritonitis model

Unveiling risk factors: a prognostic model of frequent peritonitis in peritoneal dialysis patients

IntroductionPeritoneal dialysis-associated peritonitis (PDAP) is a serious complication of peritoneal dialysis (PD) patients. The aim of this study was to construct a risk prediction model for frequent episodes in PDAP patients.MethodsThis retrospective cohort study included PDAP patients in our center from January 1, 2010 to December 31, 2021. The risk prediction model for frequent episodes in PDAP patients was constructed by the binary logistic regression.ResultsWe included 371 PDAP patients, of which 235 patients had single episode and 136 had frequent episodes. We randomly allocated the patients into training set (296 patients) and test set (75 patients) in the ratio of 8:2. In the training set, we found several independent risk factors significantly associated with frequent episodes in PDAP patients, including diabetes mellitus (DM), hemoglobin (HB), serum albumin (ALB), lactatic dehydrogenase (LDH), serum potassium (K), N-terminal pro-brain natriuretic peptide (NT-proBNP) and peritoneal dialysate white cell counts on day 1. And we constructed a prediction model with an area under curve (AUC) values of 0.75 in the training set and 0.76 in the test set, which showed excellent predictive performance.ConclusionWe constructed a predictive model that demonstrated excellent predictive performance for identifying high-risk frequent episodes in PDAP patients and developed a more intuitive nomogram for evaluating the risk. However, multicenter studies with a larger sample size are warranted to validate the model in the future.

PEPITEM, its tripeptide pharmacophores and their peptidomimetic analogues regulate the inflammatory response through parenteral and topical dosing in models of peritonitis and psoriasis.

PEPITEM is an immune-modulatory peptide that effectively regulates inflammation and mitigates immune-mediated inflammatory diseases (IMIDs). Here, we identify two independently active tripeptide pharmacophores within PEPITEM and engineered peptidomimetics with enhanced pharmacodynamic properties. These peptidomimetics regulate T-cell trafficking in vitro and reduce T-cell, neutrophil and macrophage numbers in the inflamed peritoneal cavity in vivo. In a plaque psoriasis model, topical administration reduced disease severity, inflammation and immune cell infiltration, while regulating cytokine release in macrophages and fibroblasts, as well as keratinocyte proliferation. Th1 and Th17 cell abundance, along with their cytokines, was reduced in secondary lymphoid organs. This expanded functional repertoire of PEPITEM and its derivatives provides innovative tools for countering immune and stromal cell-induced pathology in IMIDs. Moreover, by identifying significantly smaller tripeptide pharmacophores of 14 amino acid PEPITEM, we may be able to deliver substantial financial advantages in synthesis and formulation. The order of magnitude increase in efficacy observed for some peptidomimetics may deliver agents with enhanced pharmacological characteristics compared to the parent PEPITEM sequence. Taken together with other reports on the efficacy of PEPITEM, this study paves the way for the development and translation of a novel class of anti-inflammatory agents which may have utility in a broad range of autoimmune and chronic inflammatory diseases.

Combating Antibiotic-Resistant Bacterial Infection Using Coassembled Dimeric Antimicrobial Peptide-Based Nanofibers.

The emergence of multidrug-resistant (MDR) pathogens, coupled with the limited effectiveness of existing antibiotics in eradicating biofilms, presents a significant threat to global health care. This critical situation underscores the urgent need for the discovery and development of antimicrobial agents. Recently, peptide-derived antimicrobial nanomaterials have shown promise in combating such infections. Amino acid noncovalent forces, notably π-π stacking and electrostatic interactions, remain underutilized for guiding the coassembly of peptides into bacteriostatic nanomaterials. Thus, we constructed a dimeric nanopeptide system using the disulfide bonds of cysteine. The self-assembly of dimeric peptides into nanofibers was realized by the interaction of π-π aromatic amino acids (Trp, Phe, and Pyr) and the electrostatic attraction between oppositely charged amino acids (Asp and Arg). The optimal dimeric peptide 2D2W exhibits potent antibacterial activity against resistant bacteria and is nontoxic. Mechanistically, 2D2W penetrated the outer membrane after electrostatic adsorption, resulting in plasma membrane depolarization, homeostatic disruption, and ultimately bacterial death. In a mouse model of peritonitis, 2D2W demonstrated efficacy in the in vivo treatment of bacterial infections. In conclusion, the design of dimeric nanopeptides co-driven by intermolecular forces provides a promising avenue for the development of high-performance antimicrobial nanomaterials. These advances may also facilitate the application and advancement of peptide-based bacteriostatic agents in clinical practice.

Curcumin reverses high-level tigecycline resistance mediated by different mechanisms in Gram-negative bacteria.

Tigecycline is one of the few effective treatments for multidrug-resistant bacteria. However, the recent emergence and spread of high-level tigecycline resistance in Enterobacteriaceae have significantly limited its clinical use. To combat this challenge, combining antibiotics with adjuvants has emerged as a promising strategy. Curcumin, known for its antibacterial properties and ability to enhance antibiotic efficacy, presents a viable option for reversing tigecycline resistance. This study aimed to evaluate the in vitro and in vivo synergistic effects of curcumin and tigecycline in gram-negative bacteria with different tigecycline resistance mechanisms and to elucidate the molecular mechanisms by which curcumin reverses tigecycline resistance. The checkerboard assay was used to evaluate the synergistic effects of tigecycline and curcumin, while the time-killing curves were used to assess their antibacterial activity. The study also examined their impact on biofilm eradication, the development of tigecycline resistance, and the conjugative transfer of tigecycline-resistant plasmids. The molecular mechanisms underlying the combined effect were investigated. Additionally, the in vivo efficacy of the tigecycline-curcumin combination against tigecycline-resistant Escherichia coli was assessed using a mouse peritonitis infection model. This study revealed that curcumin and tigecycline exhibited synergistic effects against tigecycline-resistant gram-negative bacteria with various resistance mechanisms in vitro. Notably, the addition of curcumin delayed the development of tigecycline resistance in E. coli and impeded the horizontal transfer of tet(X4)-positive IncX1 plasmid. The curcumin-tigecycline combination significantly disrupted cell membrane integrity and reduced efflux pump activity by modulating proton dynamics and inhibiting ATP synthesis. Transcriptomic and proteomic analyses supported these findings, revealing disruptions in central carbon metabolism and substantial effects on the electron transport chain. In vivo experiments using a peritonitis model induced by the tet(X4)-carrying E. coli ZZ9DT16R demonstrated that the curcumin-tigecycline combination improved survival rates, reduced bacterial counts, and enhanced liver and spleen histopathology. Furthermore, the expression of the tet(X4) gene was reduced, and molecular docking studies indicated that curcumin binds to diverse tigecycline resistance proteins. This study is the first to reveal the synergistic action of curcumin and tigecycline, highlighting its potential as a combined therapeutic strategy against tigecycline-resistant gram-negative pathogens with various resistance mechanisms.

The effect of dehydroepiandrosterone on oxygen-dependent microbicidal activity of blood leukocytes in zymosan peritonitis in old rats

The purpose of the present work was to study effects of dehydroepiandrosterone (DHEA) on the oxygen-dependent microbicidal activity of blood leukocytes. The studies were performed on male white nonlinear rats aged 3-6 months (young rats) and adult animals over 1.5 years old (old rats) using an experimental model of zymosan peritonitis. DHEA was administered subcutaneously to old animals on the daily basis (a total of 4 injections of 2 mg/kg body weight, the last injection 24 hours before the end of the experiment). Rats of similar age served as controls and received DHEA solvent (officinal olive oil) according to the same time regimen. 12 hours before the end of the experiment, the animals were administered a sterile suspension of zymosan A intraperitoneally at a dose of 50 mg/kg. The oxygen-dependent microbicidal activity of blood leukocytes was assessed by luminol-dependent chemiluminescence using opsonized and non-opsonized zymosan at concentrations of 15 μg/mL, 150 μg/mL and 1500 μg/mL. In old male rats, compared to young ones, the chemiluminescence indexes showed a statistically significant increase when blood leukocytes were stimulated with both opsonized and non-opsonized zymosan. Administration of DHEA to old male rats leads to a pronounced decrease in chemiluminescence in samples at all concentrations of opsonized zymosan. When leukocytes of old animals are stimulated with non-opsonized zymosan in vitro, a statistically significant increase in the production of reactive oxygen species was observed, being more pronounced at lower concentrations of inducing agent (15 μg/mL and 150 μg/mL). Meanwhile, this effect was canceled at high concentrations of zymosan. The level of spontaneous chemiluminescence, reflecting in vivo cell activation, was higher in old rats treated with DHEA compared to young animals. The direction of changes in the production of reactive oxygen species in samples with low concentrations of the in vitro activation was similar to the effects of DHEA in old rats tested for spontaneous chemiluminescence. In general, our studies confirm the pronounced immunomodulatory activity of DHEA. In general, we have found that aging of male rats leads to pronounced pro-inflammatory activation of reactive oxygen species produced by blood leukocytes at the peak of inflammation induced by zymosan injections. Administration of DHEA to old male rats significantly reduced the production of reactive oxygen species by blood leukocytes, when the cells were in vitro activated by opsonized zymosan, but stimulates production of oxygen radicals in the samples without zymosan, as well as upon exposition to non-opsonized zymosan at concentrations of 15 μg/mL and 150 μg/ mL.

BODIPY-Based Ratiometric Fluorescent Probe for Sensing Peroxynitrite in Inflammatory Cells and Tissues.

Peroxynitrite (ONOO-) plays an important role in many physiological and pathological processes. Excessive ONOO- in cells leads to oxidative stress and inflammation. However, precise monitoring of ONOO- levels in specific organelles (e.g., mitochondria) is still lacking and urgently needed. Herein, we rationally designed a mitochondria-targeted ratiometric fluorescent probe, MOBDP-I, for imaging of ONOO- in the mitochondria of inflammatory cells and model mice. This probe, MOBDP-I, was synthesized by conjugating a BODIPY fluorophore to a mitochondria-targeting moiety-indole-salt group by a carbon-carbon double bond (C=C). In the presence of ONOO-, the C=C bond between the BODIPY backbone and the indole-salt group was oxidized and broken, leading to an 18-fold enhancement of fluorescence at 510 nm, along with a significant fluorescence decrease at 596 nm. The ratiometric response property bestowed the probe with advantages in the precise quantification of ONOO- in cells, thus allowing estimation of the extent of inflammation in living cells and mouse models of rheumatoid arthritis, peritonitis, and brain inflammation. MOBDP-I could act as an effective molecular tool to study the relationship between ONOO- and the occurrence and development of inflammatory diseases.

Extinguishing the flames of inflammation: retardant effect of chlorquinaldol on NLRP3-driven diseases

BackgroundNLRP3 inflammasome immoderate activation results in the occurrence of various inflammatory diseases, but the clinic medications targeting NLRP3 inflammasome are still not available currently. The strategy of drug repurposing can reorient the direction of therapy, which is an indispensable method of drug research. In this study, an antimicrobial agent chlorquinaldol (CQ) was conducted to assess the effect on NLRP3 inflammasome and novel clinical value on NLRP3-driven diseases.MethodsThe effect of CQ on NLRP3 inflammasome activation and pyroptosis was studied in mouse and human macrophages. ASC oligomerization, intracellular potassium, reactive oxygen species production, and NLRP3-ASC interaction were used to evaluate the suppression mechanism of CQ on inflammasome activation. Finally, the ameliorative effects of CQ in the model of LPS-induced peritonitis, dextran sodium sulfate (DSS)-induced colitis, and monosodium urate (MSU)-induced gouty arthritis were evaluated in vivo.ResultsCQ is a highly powerful NLRP3 inhibitor that has feeble impact on the NLRC4 or AIM2 inflammasome activation in mouse and human macrophages. Further study indicated that CQ exhibits its suppression effect on NLRP3 inflammasome by blocking NLRP3-ASC interaction and hydroxyl on the benzene ring is vital for the assembly and activation of NLRP3 inflammasome. Furthermore, in vivo experiments demonstrated that administration of CQ has outstanding therapeutic action on LPS-induced peritonitis, DSS-induced colitis, and MSU-induced gouty inflammation in mice.ConclusionsCollectively, the current study discoveries the antimicrobial agent CQ as a potentially specific NLRP3 inhibitor, and its use provides a feasible therapeutic approach for the treatment of NLRP3-driven diseases.

Impact of the inoculum size on the in vivo activity of the aztreonam-avibactam combination in a murine model of peritonitis due to Escherichia coli expressing CTX-M-15 and NDM-1.

The combination of aztreonam (ATM) and avibactam (AVI) is an attractive option to treat infections caused by extended spectrum β-lactamase plus NDM-1-producing Enterobacteriaceae. Since ATM activity was shown to be severely impacted by an increase in the inoculum size in vitro, we wondered whether ATM-AVI activity could be impaired in high-inoculum infections. We analyzed the impact of the inoculum size on ATM-AVI activity in vitro and in a murine model of peritonitis due to susceptible Escherichia coli CFT073-pTOPO and its isogenic derivatives producing NDM-1 (E. coli CFT073-NDM1) and CTX-M-15 plus NDM-1 (E. coli CFT073-CTXM15-NDM1). The impact of the inoculum size on bacterial morphology was studied by microscopic examination. In vitro, at standard (105) inoculum, E. coli CFT073-CTXM15-NDM1 was resistant to ATM but susceptible to the ATM-AVI combination. At high (107) inoculum, MICs of ATM alone and of the ATM-AVI combination reached >512 and 64 mg/L, respectively, against all tested strains. ATM led to bacterial filamentation when active against the bacteria, i.e., in monotherapy or in combination with AVI against susceptible E. coli CFT073-pTOPO and only in combination with AVI against E. coli CFT073-CTXM15-NDM1. In vivo, increase in the inoculum led to a drastic decrease in the activity of ATM alone against E. coli CFT073-pTOPO and ATM-AVI against E. coli CFT073-CTXM15-NDM1. Our results suggest a high in vivo impact of the inoculum increase on the activity of ATM alone against ATM-susceptible E. coli and of ATM-AVI against CTX-M-15 plus NDM-1 producing E. coli. Clinicians must be aware of the risk of failures when using ATM-AVI in high-inoculum infections.

Repurposing zidovudine and 5-fluoro-2'-deoxyuridine as antibiotic drugs made possible by synergy with both trimethoprim and the mitochondrial toxicity-reducing agent uridine.

The increasing frequency of antibiotic-resistant bacterial infections is a major public health challenge, and new antibiotic drugs are urgently needed. A rapid solution to the problem is to repurpose clinically approved compounds with antibacterial properties, such as the nucleoside analogues zidovudine (azidothymidine) or 5-fluoro-2'-deoxyuridine. Here we report the in vitro and in vivo antibacterial properties of double and triple combinations of azidothymidine or 5-fluoro-2'-deoxyuridine with uridine and/or trimethoprim. We determined MICs of azidothymidine and 5-fluoro-2'-deoxyuridine, alone or combined with uridine and/or trimethoprim, against a selection of Gram-negative and Gram-positive bacteria. We also measured MICs of a selection of antibiotics of different classes as a function of uridine concentration. The efficacy of azidothymidine and 5-fluoro-2'-deoxyuridine with uridine and/or trimethoprim was measured in a murine peritonitis infection model. The addition of uridine enhanced the in vitro antibacterial activity of azidothymidine and 5-fluoro-2'-deoxyuridine, against Gram-negative and Gram-positive bacteria, respectively. Uridine also enhanced the in vitro antibacterial activity of azidothymidine/trimethoprim and 5-fluoro-2'-deoxyuridine/trimethoprim combinations. Triple combinations containing azidothymidine, trimethoprim and uridine, showed antibacterial synergy against Gram-negative bacteria (Escherichia coli and Klebsiella pneumoniae) whereas the 5-fluoro-2'-deoxyuridine, trimethoprim and uridine combination showed synergy against the Gram-positive Staphylococcus aureus. The positive effect of uridine on the efficacy of azidothymidine/trimethoprim combination was also observed in vivo in a murine E. coli peritonitis model. Triple combinations of these clinically approved compounds warrant further investigations as therapies to combat antibiotic-resistant infections.

Hypocrellin A from an ethnic medicinal fungus protects against NLRP3-driven gout in mice by suppressing inflammasome activation.

Abnormal activation of NLRP3 inflammasome causes the progression of gout, and no small-molecule inhibitor of NLRP3 has been approved yet for clinical use. In this study we established a nigericin-induced inflammasome activation cell model for screening of a natural product library by measuring IL-1β secretion in cell supernatants. Among 432 compounds tested, we found that hypocrellin A (HA), one of the major active components of a traditional ethnic medicinal fungus Hypocrella bambusea in the Northwest Yunnan of China, exhibited the highest inhibition on IL-1β production (IC50 = 0.103 μM). In PMA-primed THP-1 cells or bone marrow derived macrophages (BMDMs) treated with multiple stimuli (nigericin, ATP or MSU), HA dose-dependently suppressed the activation of NLRP3 inflammasome, reducing the subsequent release of inflammatory cytokines and LDH. Furthermore, the suppression of inflammasome activation by HA was specific to NLRP3, but not to AIM2 or NLRC4. In LPS-primed BMDMs treated with nigericin, HA inhibited ASC oligomerization and speckle formation, and blocked the NLRP3-NEK7 interaction during inflammasome assembly without influencing the priming stage. Moreover, we demonstrated that HA directly bound to the NACHT domain of NLRP3, and that Arg578 and Glu629 were the critical residues for HA binding to NLRP3. In MSU-induced peritonitis and acute gouty arthritis mouse models, administration of HA (10 mg/kg, i.p., once or twice daily) effectively suppressed the inflammatory responses mediated by NLRP3 inflammasome. We conclude that HA is a broad-spectrum and specific NLRP3 inhibitor, and a valuable lead compound to develop novel therapeutic inhibitors against NLRP3-driven diseases. This study also elucidates the anti-inflammation mechanisms and molecular targets of HA, a major active component in medicinal fungus Hypocrella bambusea that has been long used by Chinese ethnic groups.

Rosthornin B alleviates inflammatory diseases via directly targeting NLRP3.

Aberrant activation of the NLRP3 inflammasome contributes to the evolution of diverse inflammatory diseases. Inhibition of the NLRP3 inflammasome has been proven to be an effective treatment strategy for NLRP3-driven diseases. This study revealed that multiple natural diterpenes from Isodon plants can inhibit the NLRP3 inflammasome, among which Rosthornin B (Ros B) exhibited the best inhibitory effect, with an IC50 of 0.39 μM. Further study revealed that Ros B directly interacts with NLRP3, thereby restraining NEK7-NLRP3 interaction and inhibiting NLRP3 inflammasome assembly and activation. Remarkably, Ros B had a significant therapeutic benefit in mouse models of NLRP3-driven septic shock, peritonitis, and colitis. Our study has identified a series of natural diterpenes that target the NLRP3 inflammasome. These natural diterpenes, especially those with low IC50 values, may lead to the development of new drugs and potential clinical therapies for diseases driven by NLRP3 inflammasome activation.

Antiedematogenic and Anti-Inflammatory Effects of the Essential Oil from the Fruits of Piper tuberculatum Jacq. (Piperaceae) in Animal Models.

Piper tuberculatum, traditionally known in Brazil as 'pimenta-d'arda,' 'pimenta-longa,' or 'pimenta de macaco,' has been used in Brazilian folk medicine to treat inflammatory symptoms. Considering this species' significant essential oil content, the present study aimed to evaluate the anti-edematogenic and anti-inflammatory effects of the crucial oil Piper tuberculatum (EOPT) in vivo. To this end, Swiss mice (Mus musculus) of both sexes were treated orally with the EOPT at 50, 100, and 250 mg/Kg. The rotarod and open field evaluated the potential activity in the central nervous system. At the same time, formalin and abdominal writhing tests were carried out to perform the pharmacological screening of the essential oil. Next, the anti-edematogenic effect was assessed using paw edema models induced by carrageenan, dextran, histamine, and arachidonic acid. The anti-inflammatory activity was then characterized in peritonitis (acute) and granuloma (chronic) models. The EOPT treatment at the highest dose (250 mg/kg) showed no indication of central activity. All the EOPT doses (50, 100, and 250 mg/kg) had analgesic effects associated with anti-inflammatory mechanisms in screening models. Accordingly, the treatment (EOPT 100 mg/Kg) inhibited the inflammatory process in acute and chronic models. In conclusion, EOPT has analgesic, antiedematogenic, and anti-inflammatory effects, highlighting its potential use in developing anti-inflammatory drugs.

Colchicine inhibits monosodium urate crystal-mediated inflammation by influencing F-actin formation

ObjectivesTo understand the mechanism by which colchicine inhibits the inflammatory properties of monosodium urate (MSU) crystal deposits and tophi. MethodsWe investigated the effects of colchicine on the inflammatory properties of monosodium urate (MSU) crystal deposits in several models: (i) In vitro tophus formation by MSU and neutrophils; (ii) MSU-induced peritonitis model; (iii) Alpha-1-antitrypsin-induced peritoneal MSU flare model; (iv) MSU-induced arthritis model. We measured neutrophil numbers, NET formation, IL-1β production and F-actin generation by MSU crystals. In addition, we tested the effect of actin inhibitors SMIFH2, Cytochalasin B and Latrunculin B in the models. ResultsColchicine did not affect neutrophil numbers in all these models. However, colchicine was highly effective to inhibit NET formation, IL-1β production and F-actin generation indicating less pronounced tophus formation, lower inflammatory properties of tophi and reduced conversion from G-actin into F-actin, respectively. F-actin was shown to accumulate in tophi without presence of colchicine and being resistant to degradation by DNase I. Actin inhibitors SMIFH2 and Cytochalasin B significantly reduced IL-1β and neutrophil elastase levels and mitigated MSU-induced arthritis. ConclusionColchicine effects on gout flares are not based on reducing neutrophil numbers but on changing the functional properties of tophi by reducing their DNase-resistant F-actin concentrations and thereby reducing the negative impact of NETs on IL-1β production and the pro-inflammatory state of tophi. Actin inhibitors may be interesting tools to convey anti-inflammatory properties and reduction of flares in gout patients.

IL1R2 Acts as a Negative Regulator of Monocyte Recruitment During Inflammation.

IL1-β plays a central role in inflammation but its biological action needs to be tightly controlled. Such negative regulation can be exerted by the decoy receptor IL1R2. However, IL1R2 biology in immune cells remains poorly characterized, in particular in monocytes. Using conditional deficient mice, we show that Il1r2 deficiency in monocytes does not affect their steady-state life cycle but dysregulates their trafficking to inflamed tissues in models of peritonitis and neuro-inflammation. Mechanistically, we found that Il1r2 deficiency in monocytes increases CCL2 secretion in the inflamed peritoneum, thereby amplifying monocyte recruitment from blood. In autoimmune neuro-inflammation, Il1r2 deficiency in monocytes exacerbates disease severity. Our findings suggest that the specific action of IL1R2 in monocytes contributes to a feedback mechanism for fine-tuning the numbers of recruited monocytes during inflammation.

Bactericidal antibiotic treatment induces damaging inflammation via TLR9 sensing of bacterial DNA

The immunologic consequences of using bactericidal versus bacteriostatic antibiotic treatments are unclear. We observed a bacteriostatic (growth halting) treatment was more protective than a bactericidal (bacteria killing) treatment in a murine peritonitis model. To understand this unexpected difference, we compared macrophage responses to bactericidal treated bacteria or bacteriostatic treated bacteria. We found that Gram-negative bacteria treated with bactericidal drugs induced more proinflammatory cytokines than those treated with bacteriostatic agents. Bacterial DNA – released only by bactericidal treatments – exacerbated inflammatory signaling through TLR9. Without TLR9 signaling, the in vivo efficacy of bactericidal drug treatment was rescued. This demonstrates that antibiotics can act in important ways distinct from bacterial inhibition: like causing treatment failure by releasing DNA that induces excessive inflammation. These data establish a novel link between how an antibiotic affects bacterial physiology and subsequent immune system engagement, which may be relevant for optimizing treatments to simultaneously clear bacteria and modulate inflammation.

An amphipathic peptide combats multidrug-resistant Staphylococcus aureus and biofilms

The emergence of drug-resistant Staphylococcus aureus (S. aureus) has resulted in infections in humans and animals that may lead to a crisis in the absence of highly effective drugs. Consequently, the development of alternative or complementary antimicrobial agents is urgently needed. Here, a series of peptides derived from AP138 were designed with high expression, antimicrobial activity, and antibiofilm properties via bioinformatics. Among them, the best derived peptide, A24 (S9A), demonstrated the greatest stability and bactericidal efficiency against multidrug-resistant S. aureus in a physiological environment, with a high hydrophobicity of 35%. This peptide exhibited superior performance compared to the preclinical or clinical antimicrobial peptides (AMPs). A24 displayed increased biocompatibility in vitro and in vivo, exhibiting a low hemolysis rate (less than 3%), minimal cytotoxicity (survival rate exceeding 85%), and no histotoxicity. A24 had the capacity to destroy cell walls, increase cell membrane permeability, and induce increases in intracellular ATP and ROS levels, which resulted in the rapid death of S. aureus. A24 inhibited the formation of early biofilms and eliminated both mature biofilms (40–50%) and persisters (99.9%). Therapeutic doses of A24 were shown to exhibit favorable safety profiles and bactericidal efficacy in vivo and could reduce bacterial loads of multidrug-resistant S. aureus by 4–5 log10 CFU/0.1g levels in mouse peritonitis and endometritis models. Furthermore, A24 increased the survival rate to 100% and exhibited anti-inflammatory properties in a mouse model. The aforementioned data illustrate the potential of A24 as a pharmaceutical agent for the treatment of bacterial infections, including peritonitis and endometritis, in animal husbandry with multidrug-resistant S. aureus infections.

A near-infrared ONOO−-activated fluorescent probe for real-time visualizing of alcoholic liver disease

Alcoholic liver disease (ALD) is a liver disease which caused by excessive drinking. It is deeply associated with liver inflammation and brings about up-regulation of reactive oxygen species including peroxynitrite (ONOO−). In this work, we developed a near-infrared (NIR) ONOO−-activated fluorescent probe BDP-NIR-ONOO for real-time visualizing of alcoholic liver disease. BDP-NIR-ONOO showed excellent response to ONOO− in vitro tests, with NIR emitting wavelength (700 nm), good specificity, fast response speed (80 s), and high signal to noise ratio (252-fold). BDP-NIR-ONOO could detect the up-regulation of ONOO− content in the mouse peritonitis model and realize the diagnosis of inflammation in mice. Meanwhile, BDP-NIR-ONOO could image endogenous ONOO− in mice tumor. Most importantly, one mimic risky drinking ALD mice models and one mimic excessive drinking ALD mice models were established, BDP-NIR-ONOO could visualize the alcoholic liver injury of mice by imaging the ONOO− fluctuation in ALD mice, which providing a powerful tool for the diagnosis of ALD. Finally, BDP-NIR-ONOO was further utilized to dynamically trace the therapeutic effect of N-acetylcysteine on ALD.

Bactericidal effect of far ultraviolet-C irradiation at 222 nm against bacterial peritonitis.

Far ultraviolet-C irradiation at 222 nm has potent bactericidal effects against severe infections such as peritonitis, with minimal cytotoxicity. Bacterial peritonitis due to bowel perforation is a serious condition with high mortality despite current treatments. This study investigated the safety and efficacy of intraperitoneal far ultraviolet-C irradiation at 222 nm. In vitro experiments optimized the fluid conditions for bacterial or protein concentrations prior to in vivo evaluation. In vivo efficacy was assessed in a rat peritonitis model induced by Escherichia coli, measuring intra-abdominal bacterial concentration, blood cytokine levels, and mortality rates. Safety was evaluated by analyzing cyclobutane pyrimidine dimers as markers of DNA damage in five abdominal organs: stomach, small intestine, colon, liver, and spleen. Statistical analyses employed parametric methods for normally distributed data and non-parametric methods for data without normality. Optimal in vitro conditions included 106 CFU/mL bacteria, 0.5 mW/cm2 irradiation, and 10-3 mg/mL protein. In the rat model, far ultraviolet-C irradiation at 222 nm significantly decreased intra-abdominal bacteria, reduced blood cytokines (interleukin-1β and interleukin-6), and elevated survival rates from 20% to 60%, compared to lavage alone. The formation of cyclobutane pyrimidine dimers was significantly lower with 222 nm irradiation than with 254 nm, suggesting reduced DNA damage. These findings indicate that far ultraviolet-C irradiation at 222 nm, when combined with lavage, represents a promising therapeutic strategy for bacterial peritonitis, providing effective bacterial reduction and a favorable safety profile. Further research is needed to verify these findings and investigate long-term safety and potential clinical applications.

Hepcidin Exacerbates Iron Metabolism Imbalance in Septic Mice.

Sepsis is a life-threatening condition associated with acute organ dysfunction. Iron is an essential trace element for multicellular organisms and almost all microorganisms, and its role in sepsis has been increasingly recognized. The aim of this study was to investigate the changes in iron metabolism in caecal ligation and puncture solution (CLP) -induced septic mice and the effects of hepcidin pretreatment on serum inflammatory marker levels and liver iron metabolism in CLP-induced septic mice. C57BL/6 mice were given normal saline, CLP (peritonitis model) or 100μg of hepcidin via intraperitoneal injection. The experimental animals were divided into 4 groups: the control group, model group (CLP), hepcidin pretreatment Groups CLP+hepcidin-2h and CLP+hepcidin-24h. Blood samples were collected at 6, 12 and 24hours after CLP surgery, and the mice were euthanized and livers were obtained. ELISA revealed that hepcidin pretreatment, especially 2hours in advance (p<0.01), increased the serum hepcidin, TNF-a and IL-6 in CLP-induced septic mice; the serum iron content of CLP-related septic mice decreased (P<0.01), while the liver iron content increased (P<0.01); Hepcidin pretreatment reduced the serum iron (P<0.05) at 6h and 12h and liver iron concentrations (P<0.01) at 6h, 12h and 24h in CLP-related septic mice. Western blotting revealed that the hepatic iron absorption-related proteins transferrin receptor-2 (TFR2), ZRT/IRT-like protein 14 (ZIP14) and divalent meta lion transporter-1 (DMT1) were elevated (P<0.01); The iron-exporting protein ferroportin (SLC40A1) was decreased (P<0.01) throughout CLP and CLP+hepcidin sepsis. Compared with CLP group, the protein expressions in the CLP+ hepcidin-2h group were more obvious than that in the CLP+ hepcidin-24h group. Hepcidin has proinflammatory effect. Hepcidin exacerbates iron metabolism imbalances in sepsis by influencing the expression of iron absorption-related proteins and iron export-related proteins.