Endocytosis of peroxiredoxin 1 links sterile inflammation to immunoparalysis in pediatric patients following cardiopulmonary bypass

Cardiopulmonary bypass associated acute kidney injury: better understanding and better prevention

Cardiopulmonary bypass (CPB) is a common technique in cardiac surgery but is associated with acute kidney injury (AKI), which carries considerable morbidity and mortality. In this review, we explore the range and definition of CPB-associated AKI and discuss the possible impact of different disease recognition methods on research outcomes. Furthermore, we introduce the specialized equipment and procedural intricacies associated with CPB surgeries. Based on recent research, we discuss the potential pathogenesis of AKI that may result from CPB, including compromised perfusion and oxygenation, inflammatory activation, oxidative stress, coagulopathy, hemolysis, and endothelial damage. Finally, we explore current interventions aimed at preventing and attenuating renal impairment related to CPB, and presenting these measures from three perspectives: (1) avoiding CPB to eliminate the fundamental impact on renal function; (2) optimizing CPB by adjusting equipment parameters, optimizing surgical procedures, or using improved materials to mitigate kidney damage; (3) employing pharmacological or interventional measures targeting pathogenic factors.

T-cell lymphopenia is associated with an increased infecting risk in children after cardiopulmonary bypass

BACKGROUND

children who undergo CPB operations are at an elevated risk of infection due to immunosuppression. This study aims to investigate the association between lymphopenia following CPB and early postoperative infection in children.

METHODS

A retrospective analysis including 41 children under 2 years old underwent CPB. Among them, 9 subjects had an early postoperative infection, and 32 subjects were period-matched without infection. Inflammatory cytokines, serum CRP and PCT values were measured in plasma, additionally, circulating total leucocyte and lymphocyte subpopulations were counted.

RESULTS

Infected subjects exhibited significantly higher levels of inflammatory cytokines, including IL-6, IL-8, IL-10, IL-1β and TNF-α, than non-infected subjects after CPB. Additionally, lower absolute number of lymphocyte and their subpopulations CD3+ T cells, CD4+ T-helper cells and CD8+cytotoxic T-cells, were observed in infected subjects. The impairment of T-cells Immune was found to be associated with higher levels of inflammatory cytokines IL-10. The ROC demonstrated that the absolute number of CD3+ T-cells <1934/ul, CD4+ T helper cells <1203/ul and CD8+cytotoxic T-cells <327/ul were associated with early postoperative infection.

CONCLUSION

Higher levels of inflammatory cytokines resulted in T-cells lymphopenia after CPB, which significantly increasing the risk of postoperative infection in infants and young children.

IMPACT

Infection complications after cardiopulmonary bypass (CPB) in pediatric CHD patients are serious issues, identifing the infection from after CPB remains a challenging. CPB can release numerous inflammatory cytokines associated with T cells lymphopenia, which increases the risk of postoperative infection after surgery. Monitoring T cells lymphopenia maybe more beneficial to predict early postoperative infection than C-reactive protein and procalcitonin.

Lipid raft interacting galectin 8 regulates primary ciliogenesis

Primary cilium is a specialized sensory organelle that transmits environmental information into cells. Its length is tightly controlled by various mechanisms such as the frequency or the cargo size of the intraflagellar transport trains which deliver the building materials such as tubulin subunits essential for the growing cilia. Here, we show the sialoglycan interacting galectin 8 regulates the process of primary ciliogenesis. As the epithelia become polarized, there are more galectin 8 being apically secreted and these extracellular galectin 8 molecules apparently bind to a lipid raft enriched domain at the base of the primary cilia through interacting with lipid raft components, such as GD3 ganglioside and scaffold protein caveolin 1. Furthermore, the binding of galectin 8 at this critical region triggers rapid growth of primary cilia by perturbing the barrier function of the transition zone (TZ). Our study also demonstrates the functionality of this barrier depends on intact organization of lipid rafts at the cilia as genetically knockout of Cav1 and pharmacologically inhibition of lipid raft both phenocopy the effect of apical addition of recombinant galectin 8; that is, rapid elongation of primary cilia and redistribution of cilia proteins from TZ to the growing axoneme. Indeed, as cilia elongated, endogenous galectin 8, caveolin 1, and TZ component, TMEM231, also transited from the TZ to the growing axoneme. We also noted that the interaction between caveolin 1 and TMEM231 could be perturbed by exogenous galectin 8. Taken together, we proposed that galectin 8 promoted primary cilia elongation through impeding the barrier function of the TZ by interfering with the interaction between caveolin 1 and TMEM231.

Peroxiredoxin 1 regulates crosstalk between pyroptosis and autophagy in oral squamous cell carcinoma leading to a potential pro-survival

Peroxiredoxin 1 (Prdx1), a vital antioxidant enzyme, has been proven to play an important role in the occurrence and development of cancers, but its effects on oral squamous cell carcinoma (OSCC) remain unclear. Here, we performed bioinformatics analysis and immunohistochemical (IHC) staining to confirm that Prdx1 was higher in OSCC tissues than in normal tissues. Consistently, RT-PCR and Western blot showed elevated Prdx1 expression in OSCC cell lines compared to human oral keratinocytes (HOK), which could be knockdown by small interfering RNA (siRNA) and Lentiviral vector delivery of short hairpin RNA (shRNA). Prdx1 silencing significantly blocked OSCC cell proliferation and metastasis, as evidenced by the CCK8, colony formation, in vivo tumorigenesis experiment, wound healing, transwell assays, and changes in migration-related factors. siPrdx1 transfection increased intracellular reactive oxygen species (ROS) levels and provoked pyroptosis, proved by the upregulation of pyroptotic factors and LDH release. Prdx1 silencing ROS-independently blocked autophagy. Mature autophagosome failed to form in the siPrdx1 group. Up-regulated autophagy limited pyroptosis triggered by Prdx1 deficiency, and down-regulated pyroptosis partly reversed siPrdx1-induced autophagy defect. Collectively, Prdx1 regulated pyroptosis in a ROS-dependent way and modulated autophagy in a ROS-independent way, involving the crosstalk between pyroptosis and autophagy.

The multifaceted nature of peroxiredoxins in chemical biology

Peroxiredoxins (Prx), thiol-dependent peroxidases, were first identified as H2O2 detoxifiers, and more recently as H2O2 sensors, intermediates in redox-signaling pathways, metabolism modulators, and chaperones. The multifaceted nature of Prx is not only dependent on their peroxidase activity but also strongly associated with specific protein-protein interactions that are being identified, and where the Prx oligomerization dynamics plays a role. Their oxidation by a peroxide substrate forms a sulfenic acid that opens a route to channel the redox signal to diverse protein targets. Recent research underscores the importance of different Prx isoforms in the cellular processes behind disease development with potential therapeutic applications.

Extracellular H2O2, peroxiredoxin, and glutathione reductase alter Neospora caninum invasion and proliferation in Vero cells

Neospora caninum is a protozoan member of the Apicomplexa phylum and is closely connected with abortion in cattle. The development of the parasite in host cells is characterized by the active secretion of proteins, allied to the tight control of the redox status. In this sense, elucidating the mechanisms related to the role of the redox agents and enzymes during the invasion and proliferation of N. caninum may contribute to developing novel forms of neosporosis control. In this study we verified the effects of the recombinant forms of N. caninum glutathione reductase (rNcGR) and thioredoxin-dependent peroxide reductase (rNcPrx), as well as H₂O₂ in the tachyzoite invasion and proliferation. rNcPrx interfered in the N. caninum invasion in a redox state manner. Oxidized rNcPrx inhibited the N. caninum invasion and proliferation with no toxic effects observed in Vero cells. In contrast, lower concentrations of H₂O₂ (10 μM) stimulated the N. caninum invasion, which was reverted in higher doses (>100 μM). H₂O₂ inhibited the parasite proliferation in lower concentrations than cytotoxicity in host cells, resulting in a positive selectivity index (1.8). Besides, rNcPrx (reduced and non-reduced) and rNcGR inhibited the parasite proliferation without affecting the host cell. Our results indicate the connection between the N. caninum development and the redox state, contributing to the elucidation of parasite propagation and control mechanisms.

Risk factors for venoarterial-extracorporeal membrane oxygenation related nosocomial infection in children after cardiac surgery

OBJECTIVES

Extracorporeal membrane oxygenation (ECMO) is an extracorporeal life support strategy for the treatment of critically ill children with reversible heart and lung failure, increasingly being used in patients with low cardiac output after cardiac surgery. However, the mortality of patients is closely related to the complications of ECMO, especially bleeding, thrombosis, and infection, ECMO-related nosocomial infection has become a challenge to the success of ECMO. This study aims to analyze the incidence and risk factors for venoarterial-ECMO (VA-ECMO)-related nosocomial infections in children after cardiac surgery.

METHODS

We retrospectively collected the data of patients who underwent VA-ECMO treatment after pediatric cardiac surgery in the Second Xiangya Hospital of Central South University from July 2015 to March 2021, and divided them into an infected group and a non-infected group. The clinical characteristics of the 2 groups of patients, VA-ECMO-related nosocomial infection factors, pathogenic microorganisms, and patient mortality were compared. Logistic regression was used to analyze the risk factors for nosocomial infection related to VA-ECMO after cardiac surgery.

RESULTS

Of the 38 pediatric patients, 18 patients (47.37%) had VA-ECMO related nosocomial infection, served as the infected group, including 7 patients with blood infections and 11 respiratory tract infections. Gram-negative pathogens (16 strains, 88.9%) were the main bacteria, such as Acinetobacter baumannii (6 strains), Klebsiella pneumoniae (3 strains), and Stenotrophomonas maltophilia (3 strains). Compared with the non-infected group (n=20), the infection group had longer time of cardiopulmonary bypass, time of myocardial block, and time of VA-ECMO assistance (All P<0.05). Multivariate logistic regression analysis showed that time of cardiopulmonary bypass (OR=1.012, 95% CI 1.002 to 1.022; P=0.021) was an independent risk factor for ECMO-related nosocomial infection. The number of surviving discharges in the infected group was less than that in the non-infected group (1 vs 11, P<0.05).

CONCLUSIONS

Cardiopulmonary bypass time is an independent risk factor for VA-ECMO-related nosocomial infection in children after cardiac surgery. Shortening the duration of extracorporeal circulation may reduce the incidence of VA-EMCO-related nosocomial infections in children after cardic surgery. The occurrence of VA-ECMO-related nosocomial infections affects the number of patient's discharge alive.