Cherry-red plasma: Beyond the assumption of hemolysis.

Hemolysis is the most prevalent pre-analytical interfering factor and a major source of error in laboratory analysis. The examination of samples post-centrifugation can provide valuable information regarding pre-analytical interferences. In this unusual case, a patient's plasma specimen was cherry-red after centrifugation, which is most usually indicative of hemolysis. However, subsequent investigations ruled out common hemolysis causes. We eventually determined that the patient's cherry-red plasma was most likely caused by other factors in the patient's medical history, including cancer treatment with PV-10 (rose bengal disodium 10%). We then conducted an interference study to comprehensively assess the effects of PV-10 on various biochemical tests, especially liver function tests and bilirubin levels. The findings indicate that PV-10 has varying effects on different biochemical assays and test results should be examined individually. This report underlines the need for awareness of potential drug interference on laboratory tests for better result interpretation and making clinical decisions.

Different behavior of food-related benzoic acids toward iron and copper.

Benzoic acids, which are commonly found in food, are also produced by human microbiota from other dietary phenolics. The aim was to investigate the interactions of 8 food-related benzoic acids with the physiological metals iron and copper under different (patho)physiologically relevant pH conditions in terms of chelation, reduction, impact on the metal-based Fenton chemistry, and copper-based hemolysis. Only 3,4-dihydroxybenzoic acid behaved as a protective substance under all conditions. It chelated iron, reduced both iron and copper, and protected against the iron and copper-based Fenton reaction. Conversely, 2,4,6-trihydroxybenzoic acid did not chelate iron and copper, reduced both metals, potentiated the Fenton reaction, and worsened copper-based hemolysis of rat red blood cells. The other tested compounds showed variable effects on the Fenton reaction. Interestingly, prooxidative benzoic acids mildly protected human erythrocytes against Cu-induced lysis. In conclusion, 3,4-dihydroxybenzoic acid seems to have a protective effect against copper and iron-based toxicity under different conditions.

Levofloxacin induces erythrocyte contraction leading to red cell death.

Background: Levofloxacin, a fluoroquinolone, is an extensively used antibiotic effective against both positively and negatively staining bacteria. It works by inhibiting bacterial topoisomerase type II and topoisomerase type IV, resulting in impaired DNA synthesis and bacterial cell death. Eryptosis is another term for apoptotic cell death of erythrocyte marked by cell shrinkage, phosphatidylserine (PS) flipping, and membrane blebbing. Methods: The intent of the present research was to look at the eryptotic effect of levofloxacin by exposing erythrocytes to therapeutical doses (7, 14 µM) of levofloxacin for 48 hours. Cell size evaluation, PS subjection to outside, and calcium channel inhibition were carried out to investigate eryptosis. Oxidative stress generated by levofloxacin was measured as a putative mechanism of eryptosis using glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase activities. Similarly, hemolysis measurements demonstrated levofloxacin's cytotoxic effect. Results: Our findings showed that therapeutic doses of levofloxacin can cause a considerable decline in antioxidant enzymes activities, as well as induce cell shrinkage, PS externalization, and hemolysis in erythrocytes. The role of calcium in triggering erythrocyte shrinkage was also confirmed. Conclusion: In conclusion, our findings showed that the indicated levofloxacin doses caused oxidative stress, which leads to erythrocyte death via eryptosis and hemolysis. These findings emphasize the importance of using levofloxacin with caution and the need for additional research to mitigate these side effects.

Blood trauma in veno-venous extracorporeal membrane oxygenation: low pump pressures and low circuit resistance matter.

BACKGROUND: Veno-venous extracorporeal membrane oxygenation (VV ECMO) has become standard of care in patients with the most severe forms of acute respiratory distress syndrome. However, hemolysis and bleeding are one of the most frequent side effects, affecting mortality. Despite the widespread use of VV ECMO, current protocols lack detailed, in-vivo data-based recommendations for safe ECMO pump operating conditions. This study aims to comprehensively analyze the impact of VV ECMO pump operating conditions on hemolysis by combining in-silico modeling and clinical data analysis. METHODS: We combined data from 580 patients treated with VV ECMO in conjunction with numerical predictions of hemolysis using computational fluid dynamics and reduced order modeling of the Rotaflow (Getinge) and DP3 (Xenios) pumps. Blood trauma parameters across 94,779 pump operating points were associated with numerical predictions of shear induced hemolysis. RESULTS: Minimal hemolysis was observed at low pump pressures and low circuit resistance across all flow rates, whereas high pump pressures and circuit resistance consistently precipitated substantial hemolysis, irrespective of flow rate. However, the lower the flow rate, the more pronounced the influence of circuit resistance on hemolysis became. Numerical models validated against clinical data demonstrated a strong association (Spearman's r = 0.8) between simulated and observed hemolysis, irrespective of the pump type. CONCLUSIONS: Integrating in-silico predictions with clinical data provided a novel approach in understanding and potentially reducing blood trauma in VV ECMO. This study further demonstrated that a key factor in lowering side effects of ECMO support is the maintenance of low circuit resistance, including oxygenators with the lowest possible resistance, the shortest feasible circuit tubing, and cannulae with an optimal diameter.

Oral complement factor D inhibitor danicopan for paroxysmal nocturnal hemoglobinuria.

INTRODUCTION: Paroxysmal nocturnal hemoglobinuria (PNH) is a rare hematological disorder characterized by episodic hemolysis, with additional clinical manifestations including thrombosis and bone marrow failure. The US FDA approved a complement factor D inhibitor, danicopan (Voydeya™), previously known as ACH-4471, for the treatment of extravascular hemolysis in adults with PNH on 29 March 2024. The primary purpose of this review is to examine the clinical efficacy and safety of danicopan. AREAS COVERED: We systematically searched for articles on PubMed, Web of Science, and three publishers Springer, Elsevier, Wiley up to 6 May 2024. EXPERT OPINION: Danicopan acts on the alternative pathway of the complement cascade, preferentially controlling C3 fragment-mediated extravascular hemolysis. Recommended dosage is 150 mg orally three times a day, which can be increased to 200 mg three times a day when necessary. Vaccination is required before administration to prevent infections by encapsulated bacteria. In a pivotal phase 3 trial ALPHA, danicopan significantly increased hemoglobin levels compared to placebo (p < 0.0001), 60% of patients experienced an increase in hemoglobin levels of at least 2 g/dL, compared to none in the placebo group (adjusted difference of 47%; p < 0.0001). Common adverse events during danicopan treatment include headache and upper respiratory tract infection.

Unmasking hemoglobin Köln: a rare cause of discrepancies between pulse oximetry and arterial oxygen saturation-a case report.

Discrepancies between pulse oximetry and arterial oxygen saturation can pose challenges in clinical assessment. Possible underlying causes include poor peripheral perfusion, skin pigmentation, motion artifacts, and conditions like unstable hemoglobin and methemoglobinemia. Unstable hemoglobin variants, such as hemoglobin Köln, are rare inherited mutations affecting globin genes, potentially disrupting the folding, assembly, or interactions among subunits in globin molecules and the essential interactions between heme and globin for oxygen-binding properties. In this case report, we present the case of a 44-year-old Arabic woman who underwent extensive investigations due to disparities in pulse oximetry and arterial oxygen saturation, ultimately leading to the diagnosis of the unstable hemoglobin variant, hemoglobin Köln.

Highly oxygenated antiplasmodial and non-hemolytic Δ7,9(11) stigmastane-type steroids from the twigs of Vernonia amygdalina Delile.

Chemical investigations of a methanolic extract of the twigs of Vernonia amygdalina Delile (Asteraceae) resulted in the isolation and identification of three previously undescribed highly oxygenated Δ7,9(11) stigmastane-type steroids namely vernonins U-W (1-3) along with six known compounds (4-9). The structural characterization of all the isolated compounds has been conducted via comprehensive 1D and 2D-NMR spectroscopy as well as HRMS. The seven steroidal derivatives 1-7 were evaluated for their antiplasmodial activity against the chloroquine-resistant strain P. falciparum Dd2 (PfDd2) and their hemolytic effect on human red blood cells (RBCs). Vernonins U (1), A (4) and stigmasterol-3-O-ß-d-glucopyranoside (7) showed the highest activity with IC50 values of (5.47 ± 0.01) µg/mL, (6.02 ± 0.13) µg/mL and (6.34 ± 0.80) µg/mL, respectively, against PfDd2, while vernonin W (3) showed moderate activity of (21.20 ± 0.40) µg/mL. None of the tested compounds displayed hemolytic effects on human RBCs up to 100 µg/mL indicating their safety. These results enrich the known chemistry of V. amygdalina and support its use in folk medicine for the treatment of malaria. This encourages further research towards new antiplasmodial drug candidates from this plant.

Autochthonous Human Babesia divergens Infection, England.

We describe a case of autochthonous human Babesia divergens infection in an immunocompetent woman in England. The patient had fever, hemolysis, multiorgan failure, and 18% parasitemia. We confirmed B. divergens by 18S rDNA PCR and sequencing. Clinicians should consider babesiosis as a differential diagnosis in patients with unexplained hemolysis.

Recent advances and clinical applications of red blood cell lifespan measurement.

The red blood cell (RBC) lifespan is a crucial indicator used in clinical diagnostics, treatment, and disease monitoring. This biomarker quantifies the duration that red blood cells (RBCs) circulate within the bloodstream after being released from the bone marrow, serving as a sensitive and direct indicator of red blood cell turnover. Conventional techniques for RBC lifespan measurement, including differential agglutination, 51Cr labeling, and 15N glycine labeling, each present their own set of challenges, such as complexity, radioactive exposure, and potential allergic reaction. The carbon monoxide (CO) breath test has emerged as an advanced and non-invasive alternative, indirectly assessing RBC lifespan through hemoglobin (Hb) renewal rates. This method is convenient, rapid, and lacks the drawbacks of traditional approaches. The CO breath test for RBC lifespan is widely utilized in benign anemia, malignant hematological disorders, neonatal hyperbilirubinemia, and diabetes mellitus, offering valuable insights into disease mechanisms, progression, and treatment outcomes.

Simulation of the effect of hemolysis on thrombosis in blood-contacting medical devices.

Heart failure, broadly characterized by the gradual decline of the ability of the heart to maintain adequate blood flow throughout the body's vascular network of veins and arteries, is one of the leading causes of death worldwide. Mechanical Circulatory Support is one of the few available alternative interventions for late-stage heart failure with reduced ejection fraction. A ventricular assist device is surgically implanted and connected to the left and or right heart ventricles to provide additional bloodflow, off-loading the work required by the heart to maintain circulation. Modern mechanical circulatory support devices generate non-physiological flow conditions that can lead to the damage and rupture of blood cells (hemolysis), and the formation of blood clots (thrombosis), which pose severe health risks to the patient. It is essential to improve prediction tools for blood damage to reduce the risk of hemolysis and thrombosis. A simulation-based approach examines the interaction between hemolysis and thrombosis. Incompressible finite-volume computational fluid dynamics simulations are executed on an open-hub axial flow ventricular assist device. A continuum model of thrombosis and the intrinsic coagulation process is extended to include the effect of hemolysis. The model accounts for the effect of activation of platelets by shear stress, paracrine signaling, adhesion, and hemoglobin and ADP released during hemolysis. The effect of hemolysis with thrombosis is modelled by accounting for the hyper-adhesivity of von-Willebrand Factor on extracellular hemoglobin, and the increased rate of platelet activation induced by ADP release. Thrombosis is assessed at varying inflow rates and rotor speeds, and cases are executed where thrombosis is affected by ADP release and Hb-induced hyper-adhesivity. It is found that there is a non-negligible effect from hemolysis on thrombosis across a range of rotor speeds, and that hyperadhesivity plays a dominant role in thrombus formation in the presence of hemolysis.

In Vitro Hemocompatibility of Arabinogalactan, Betulin, and Betulin Derivatives.

The hemocompatibility of arabinogalactan, betulin and its derivatives was evaluated in vitro and samples suitable for creation of nanostructures or materials in contact with blood were selected. The prospects of arabinogalactan as a component of the construct (nanostructure) for drug delivery are due to the fact that it did not affect blood/plasma coagulation (at concentrations of 0.0033-3.333 mg/ml and 0.00465-4.65 mg/ml, respectively), platelet aggregation (0.00182-0.182 mg/ml), and demonstrated the degree of erythrocyte hemolysis less than 3%. Sodium salt of betulin monosulfate, diarginine salt of betulin disulfate (up to 0.465 mg/ml), and especially betulin and allobetulin formate with procoagulant properties (degree of hemolysis less than 2%) can be used to create a material, for example, sponge, gel, active against blood coagulation.

Metallic nanoentities: Bio-engineered silver, gold, and silver/gold bimetallic nanoparticles for biomedical applications.

This present study reports the biogenic synthesis of silver nanoparticles (AgNPs), gold nanoparticles (AuNPs) and Ag/Au bimetallic nanoparticles (BNPs) using bark extract of plant Tamarix aphylla (T.A). The bark extract contained total polyphenolic compounds and total flavonoids as 0.0362 mg/mg and 0.2928 mg/mg of the dried bark extract respectively. Silver nitrate (AgNO3) and hydrogen tetra chloroaurate trihydrate (HAuCl4.3H2O) were used as precursors while deionised water and methanol (CH3OH) were used as solvents. Synthesized nanoparticles were characterized through UV-visible spectroscopy, SEM (scanning electron microscopy), TEM (transmission electron microscopy) and FTIR (Fourier transform infrared) for their morphology, structure, and identification of different functional groups. The UV-visible spectra of AgNPs, AuNPs and Ag/Au BNPs showed peaks at 436, 532 and 527 nm respectively due to the excitation of Surface Plasmon Resonance. SEM and TEM images showed spherical and well distributed nanoparticles (NPs) with particle size as 29 nm (AgNPs), 13 nm (AuNPs) and 26 nm (Ag/Au BNPs). The synthesized NPs are significantly active against inhibition of free radicals, α-amylase, α-glucosidase and have anti inflammatory potential with AgNPs having the highest percent activity at 400 µg/ml, followed by Ag/Au BNPs. The same trend (AgNPs > Ag/AuBNPs > AuNPs) has been observed at all concentrations i.e. 100 µg/ml, 200 µg/ml and 400 µg/ml. AuNPs have shown lowest activity at all concentrations. So the current study strongly confirms use of T.A bark extract as reducing agent for synthesis of metal NPs and opens up a new possibility of using these green synthesized NPs as biomedicines. We also suggest further in vivo investigation to report any side effects if present.

Antibacterial Activity and Prebiotic Properties of Six Types of Lamiaceae Honey.

Our work investigated the antimicrobial and prebiotic properties of basil, mint, oregano, rosemary, savory, and thyme honey. The potential antimicrobial action, assessed against the pathogens Acinetobacter baumannii, Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, and Staphylococcus aureus, evidenced the capacity of the honey to influence the pathogenic hydrophobicity and hemolytic activities. Honey inhibited pathogen biofilms, acting especially on the mature biofilms, with inhibition rates of up to 81.62% (caused by the presence of mint honey on L. monocytogenes). S. aureus biofilms were the most susceptible to the presence of honey, with inhibition rates up of to 67.38% in the immature form (caused by basil honey) and up to 80.32% in the mature form (caused by mint honey). In some cases, the amount of nuclear and proteic material, evaluated by spectrophotometric readings, if also related to the honey's biofilm inhibitory activity, let us hypothesize a defective capacity of building the biofilm scaffold or bacterial membrane damage or an incapability of producing them for the biofilm scaffold. The prebiotic potentiality of the honey was assessed on Lacticaseibacillus casei Shirota, Lactobacillus gasseri, Lacticaseibacillus paracasei subsp. paracasei, and Lacticaseibacillus rhamnosus and indicated their capacity to affect the whole probiotic growth and in vitro adhesive capacity, as well as the antioxidant and cytotoxic abilities, and to inhibit, mainly in the test performed with the L. casei Shirota, L. gasseri, and L. paracasei supernatants, the immature biofilm of the pathogens mentioned above.

In Vitro Evaluation of Anti-Hemolytic and Cytotoxic Effects of Traditional Mexican Medicinal Plant Extracts on Human Erythrocytes and Cell Cultures.

Plant extracts of fifteen plants of ethnomedicinal use in Mexico were analyzed to provide scientific knowledge of their medicinal properties through the evaluation of different biological activities such as anti-hemolytic, antioxidant, and cytotoxic effects in normal cells. Therefore, methanolic extracts were obtained from each of the plants by the Soxhlet extraction. The hemolytic activity in human erythrocytes was evaluated, as was their potential to protect the erythrocyte membrane against the 2,2'-azobis (2-methylpropionamidine) dihydrochloride (AAPH) and 1,1-diphenyl-2-picryl hydrazyl (DPPH) radicals. Finally, the toxicity of the extracts in normal cell cultures of African green monkey kidney cells (Vero) and peripheral blood mononuclear cells (PBMC) was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction method. Most of the extracts showed low hemolytic activity and high anti-hemolytic activity as well as high selectivity indices (SI) and antioxidant effects. Extracts of H. inuloides, J. dioica, and J. spicigera induced cell proliferation of the Vero cells. K. daigremontiana, A. adstringens, S. mexicanum, J. spicigera, L. tridentata, and M. tenuiflora extracts showed PBMC cell proliferation. In the present study, it was observed that the evaluated extracts did not present hemolytic activity, and some presented low toxicity when Vero and PBMC cell cultures were exposed. In conclusion, traditionally used plants possess beneficial health properties, and it is hoped that this study will serve as a basis for understanding the biological effects of traditionally used plants and may complement future studies.

Virulence Factors and Susceptibility to Ciprofloxacin, Vancomycin, Triclosan, and Chlorhexidine among Enterococci from Clinical Specimens, Food, and Wastewater.

Enterococcus faecalis and E. faecium are opportunistic pathogens commonly found in the microbiota of humans and other animals as well as in the environment. This article presents the results of antimicrobial susceptibility testing using phenotypic methods (broth microdilution and standardized disk diffusion) on selected clinical, food, and wastewater isolates of E. faecalis and E. faecium. The isolates were divided into subgroups based on their sensitivity to the following antibiotics: vancomycin (VAN) and ciprofloxacin (CIP), and biocides triclosan (TCL) and chlorhexidine (CHX). The study also investigated in vitro virulence factors, including biofilm formation ability, cell surface hydrophobicity (CSH) and ß-hemolysis, to explore aspects of pathogenesis. In our study, regardless of the isolation source, VAN-resistant (VAN-R) and CIP-resistant (CIP-R) E. faecalis and E. faecium were detected. The highest proportion of CIP-R strains was found among clinical isolates of E. faecalis and E. faecium, with clinical E. faecium also showing the highest proportion of VAN-R strains. But the highest proportion of VAN-R E. faecalis strains was found in wastewater samples. The highest TCL MIC90 values for E. faecalis were found in wastewater isolates, while for E. faecium, the highest TCL MIC90 values were observed in food isolates. The highest CHX MIC90 values for both E. faecalis and E. faecium were identified in clinical specimens. The results obtained for E. faecalis did not indicate differences in TCL MIC and CHX MIC values with respect to sensitivity to VAN and CIP. Higher CHX MIC50 and CHX MIC90 values were obtained for CIP-R and VAN-R E. faecium. Among the tested isolates, 97.75% of the E. faecalis isolates produced biofilm, while 72.22% of the E. faecium isolates did so as well. In biofilm-forming strength categories III and IV, statistically significantly higher proportions of CIP-susceptible (CIP-S) and VAN-susceptible (VAN-S) E. faecalis were determined. In category III, there is no statistically significant difference in E. faecium CIP sensitivity. In category IV, we had a significantly higher proportion of CIP-R strains. On the other hand, the association between the moderate or strong category of biofilm formation and E. faecium VAN susceptibility was not significant. E. faecalis isolated from wastewater had a CSH index (HI) ≥ 50%, categorizing them as "moderate", while all the other strains were categorized as "low" based on the CSH index. Among the E. faecalis isolates, cell surface hydrophobicity indices differed significantly across isolation sources. In contrast, E. faecium isolates showed similar hydrophobicity indices across isolation sources, with no significant difference found. Moreover, no correlation was found between the enterococcal cell surface hydrophobicity and biofilm formation in vitro. After anaerobic incubation, ß-hemolytic activity was confirmed in 19.10% of the E. faecalis and 3.33% of the E. faecium strains.

Therapeutics for sickle cell disease intravascular hemolysis.

Sickle cell disease (SCD) is a genetic disorder predominantly affecting individuals of African descent, with a significant global health burden. SCD is characterized by intravascular hemolysis, driven by the polymerization of mutated hemoglobin within red blood cells (RBCs), leading to vascular inflammation, organ damage, and heme toxicity. Clinical manifestations include acute pain crises, hemolytic anemia, and multi-organ dysfunction, imposing substantial morbidity and mortality challenges. Current therapeutic strategies mitigate these complications by increasing the concentration of RBCs with normal hemoglobin via transfusion, inducing fetal hemoglobin, restoring nitric oxide signaling, inhibiting platelet-endothelium interaction, and stabilizing hemoglobin in its oxygenated state. While hydroxyurea and gene therapies show promise, each faces distinct challenges. Hydroxyurea's efficacy varies among patients, and gene therapies, though effective, are limited by issues of accessibility and affordability. An emerging frontier in SCD management involves harnessing endogenous clearance mechanisms for hemolysis products. A recent work by Heggland et al. showed that CD-36-like proteins mediate heme absorption in hematophagous ectoparasite, a type of parasite that feeds on the blood of its host. This discovery underscores the need for further investigation into scavenger receptors (e.g., CD36, SR-BI, SR-BII) for their possible role in heme uptake and detoxification in mammalian species. In this review, we discussed current SCD therapeutics and the specific stages of pathophysiology they target. We identified the limitations of existing treatments and explored potential future developments for novel SCD therapies. Novel therapeutic targets, including heme scavenging pathways, hold the potential for improving outcomes and reducing the global burden of SCD.

Evaluation of a novel blood collection set for venipuncture in oncology patients with difficult venous access: Impact on sample quality, phlebotomist satisfaction and patient pain perception.

PURPOSE: Difficult venous access (DVA), characterized by non-visible and non-palpable veins, is common in oncology patients. The objectives of this study were to compare the performances of two blood collection sets in an oncology phlebotomy setting: BD Vacutainer® UltraTouch™ Push Button (UT-PBBCS) and BD Vacutainer® Safety-Lok™ Blood Collection Set (SLBCS). The two sets were evaluated to assess whether use of a smaller gauge (G) needle (down-gauging) may reduce patient pain and improve peripheral venous access experience during phlebotomy in oncology patients. METHODS: Questionnaires were used to record patient data (age, gender), phlebotomy procedural observations (venipuncture site, number of collected tubes, blood flow, needle repositioning, underfilled tubes), patient pain perception and phlebotomist difficulty perception scores (0-10 points scale). Specimen quality was evaluated by hemolysis index (HI) on Roche Cobas® 6000. RESULTS: Subject groups showed no statistical difference. SLBCS (21/23G) or UT-PBBCS (23/25G) were used in 264 (45.8%) and 313 (54.2%) subjects respectively. Lower gauge was preferred for DVA (hand venipuncture), and DVA was associated with tube underfilling but no with type of blood collection set. For UT-PBBCS, pain perception, patients' anxiety level and phlebotomists' difficulty grade were lower when compared to SLBCS (p < 0.001). Blood samples collected with UT-PBBCS showed less hemolysis compared to samples collected with SLBCS (p < 0.001). CONCLUSION: Provision of a smaller gauge UT-PBBCS option during phlebotomy in oncology patients with DVA reduces procedural pain and anxiety and improved phlebotomist' experience during sample collection. Despite the down-gauging, hemolysis was lower for UT-PBBCS, keeping sample quality while improving DVA patient comfort.

The phospholipase A of Neisseria gonorrhoeae lyses eukaryotic membranes and is necessary for survival in neutrophils and cervical epithelial cells.

Contact-dependent hemolysins are virulence factors in a number of human pathogens, including Helicobacter pylori, Rickettsia typhi, Bartonella bacilliformis, Mycobacterium tuberculosis, entero-invasive Escherichia coli, and Shigella. Here we demonstrate that Neisseria gonorrhoeae produces an outer membrane protein, phospholipase A, that exhibits contact-dependent lytic activity on host cell membranes. This enzyme can lyse human erythrocytes over a 3-day period, whereas a phospholipase A mutant cannot. We demonstrated phospholipase A activity in the parent strain but not in two, independent phospholipase A mutants. A gene for phospholipase A, pldA (hereafter referred to as pla to avoid confusion with the gene for phospholipase D, pld), is present in all sequenced gonococcal strains. Fluid phase, hemolytic activity assays showed that 25 of 29 gonococcal strains tested had hemolytic activity greater than 50% of the positive control. In support of PLA as a gonococcal outer membrane protein, supernatants from 24-, 48-, and 72-h cultures of N. gonorrhoeae strain 1291 did not contain hemolysin activity, and a monoclonal antibody specific for gonococcal phospholipase A failed to detect the enzyme in these supernatants. The organism must be viable for lysis to occur, and the inclusion of EDTA in the media removes all activity. Our studies have shown that a phospholipase A mutant has significantly reduced survival in human neutrophils and primary human cervical epithelial cells compared to the parent gonococcal strain after 3 h of incubation. Collectively, our data demonstrate that gonococcal PLA lyses host cell membranes, which is important for intracellular survival. IMPORTANCE: Intracellular survival is crucial to the success of Neisseria gonorrhoeae as a human pathogen. Multiple factors contribute to the intracellular survival of gonococci, including the ability to prohibit apoptosis of the epithelial cell the organism invades and mechanisms to evade host innate defense systems. The role of phospholipase A (PLA), an outer membrane protein, is important as it disrupts the host vacuolar and phagolysosomal membranes, preventing the effective delivery of innate immune factors that normally restrict organism growth within human cells. After cell entry, PLA disrupts the integrity of these host cell membranes, allowing the gonococcus to live free within disrupted vacuoles where it pilfers host cell nutrients that enable its survival and replication. A vaccine or drug that could neutralize PLA activity would disrupt the intracellular survival of the gonococcus.

Iptacopan Efficacy and Safety to Treat Paroxysmal Nocturnal Hemoglobinuria (PNH): A Systematic Review and Meta-Analysis.

Paroxysmal nocturnal hemoglobinuria (PNH) is an uncommon blood condition caused by complement-mediated hemolysis. In early clinical studies, iptacopan, an oral factor B inhibitor, showed promise in treating PNH. This systematic review aimed to compile information on the effectiveness and safety of iptacopan for PNH. A systematic review was performed using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) standards. The Medline, Embase, PubMed, and Cochrane Central databases were searched for randomized controlled trials (RCTs) and observational studies that evaluated iptacopan for PNH. The primary efficacy outcomes were hemoglobin and lactate dehydrogenase (LDH) changes. A fixed-effects model was used for the meta-analysis. Six studies (three prospective cohorts, two RCTs, and one non-randomized trial) were included, comprising 197 patients. Iptacopan therapy significantly increased hemoglobin levels (mean differences (MD) = 12.98 g/L; 95% CI: 11.82-14.13; p < 0.0001) and decreased LDH (MD = -83.55 IU/L; 95% CI: -83.77 to -83.34; p < 0.0001). Subgroup analyses revealed more significant hemoglobin increases in European vs. Asian populations, studies with baseline Hb > 10 g/dL vs. < 10 g/dL, and studies lasting > 24 weeks vs. ≤ 24 weeks. LDH decreases were more pronounced in studies with baseline LDH > 500 IU/L vs. < 500 IU/L. The incidence of adverse events ranged from 66% to 90%, with the most common being headache, nasopharyngitis, and diarrhea. Serious adverse events occurred in 0-20% of patients across studies. Only one patient withdrew because adverse effects were reported across all studies. Preliminary data support iptacopan's effectiveness in improving hemoglobin levels and lowering hemolysis in PNH, both as a monotherapy and in combination with usual treatment. The safety profile appears to be excellent, with a minimal incidence of major adverse events and treatment discontinuation. Further studies are needed to validate the effectiveness and safety of larger, longer-term trials. Iptacopan is a viable oral therapy option for PNH.