Search Results (921)

Thrombosis is a cardiovascular disease characterized by the pathological formation of a fibrin clot in blood vessels. Currently available fibrinolytic enzymes have some limitations, including severe side effects, high cost, short half-life, and low fibrin specificity. Proteins from microalgae and cyanobacteria have various biological effects and are emerging as promising sources for fibrinolytic enzymes. In this study, bioinformatics tools were used to evaluate the intrinsic disorder predisposition of microalgal fibrinolytic proteins, their capability to undergo liquid–liquid phase separation (LLPS), and the presence of disorder-based functional regions, and short linear motifs (SLiMs). Analysis revealed that these proteins are predominantly hydrophilic and exhibit acidic (pI 3.96–6.49) or basic (pI 8.05–11.0) isoelectric points. Most of them are expected to be moderately (61.4%) or highly disordered proteins (6.8%) and associated with LLPS, with nine proteins being predicted to behave as droplet drivers (i.e., being capable of spontaneous LLPS), and twenty-five proteins being expected to be droplet clients. These observations suggest that LLPS may be related to the regulation of the functionality of microalgal fibrinolytic proteins. The majority of these proteins belong to the blood coagulation inhibitor (disintegrin) 1 hit superfamily, which can inhibit fibrinogen binding to integrin receptors, preventing platelet aggregation. Furthermore, the SLiM-centered analysis indicated that the main motifs found in these proteins are MOD_GlcNHglycan and CLV_PCSK_SKI1_1, which can also play different roles in thrombolytic activity. Finally, Fisher and conservation analysis indicated that CLV_NRD_NRD_1, CLV_PCSK_FUR_1, CLV_PCSK_PC7_1, and MOD_Cter_Amidation motifs are enriched in intrinsically disordered regions (IDRs) of these proteins, showing significant conservation and suggesting compatibility with proteolytic activation and post-translational processing. These data provide important information regarding microalgal proteins with potential thrombolytic effects, which can be realized through protein–protein interactions mediated by SLiMs present in intrinsically disordered regions (IDRs). Additional analyses should be conducted to confirm these observations using experimental in vitro and in vivo approaches. Full article

In this work, kaolin/chitin (K/Ch) composite aerogels with different mass ratios were successfully fabricated via a freeze–drying approach. The influence of kaolin content on the microstructure, properties and hemostatic performance of the composite aerogels was systematically investigated. The results demonstrated that the incorporation of kaolin endowed the chitin-based aerogels with tunable porous structures, excellent water absorption capacity (up to 4282% for K_0.25/Ch₂), and enhanced water retention (73.7% for K₂/Ch₂ at 60 min). Moreover, the K/Ch composite aerogels exhibited good biodegradability, no cytotoxicity (cell viability > 91.9%), and no hemolysis (hemolysis rate < 1.5% at all test concentrations). In vitro hemostatic evaluations revealed that the composite aerogels exhibited rapid blood coagulation (blood clotting time of 16 s for K₂/Ch₂) with a blood coagulation index (BCI) as low as 0.5%, which was attributed to the synergistic effect of the physical adsorption of chitin and the coagulation cascade activation by kaolin. These findings indicated that the K/Ch composite aerogels could be used as novel natural hemostatic materials for potential effective and rapid hemostasis. Full article

Blood-sucking organisms produce various anticoagulant proteins that prevent blood clotting in their prey. Even in well-studied species like Hirudo medicinalis, many such proteins remain unidentified. We previously described a novel cysteine-rich anticoagulant (CRA), a distant homolog of antistasin. Later, we discovered another, much larger homolog in the medicinal leech. Its amino acid sequence is also highly cysteine-rich. Analysis of cysteine patterns showed four antistasin-like domain motifs, with one of them strongly disrupted. Since both antistasin and CRA contain two such domains, the new protein represents a duplicated antistasin-like structure. We cloned its cDNA, expressed the recombinant protein in Escherichia coli, purified it by metal-chelate chromatography, refolded it, and tested its anticoagulant properties. Using standard clinical assays—activated partial thromboplastin time, prothrombin time, and thrombin time—we found that the protein inhibited coagulation in all tests, though to varying degrees. These findings suggest that different antistasin-like anticoagulants in the leech enable it to block both intrinsic and extrinsic coagulation pathways, while hirudin inhibits the final step of clot formation. The combination of different anticoagulant proteins allows the leech to effectively prevent the prey’s blood from clotting during feeding. Full article

A facile and single-step synthesis of poly(L-Cysteine) (p(L-Cys)) particles through microemulsion polymerization using tetrakis(hydroxymethyl) phosphonium chloride (THPC) as crosslinker is accomplished for the first time. The L-Cys:THPC ratio in p(L-Cys) particles was calculated as 80:20% (by weight) with elemental analyses, and the generation of p(L-Cys) particles was confirmed. SEM imaging revealed a popcorn-like morphology of the p(L-Cys) particles with a 1–20 µm particle size range. The isoelectric point of p(L-Cys) particles was determined at pH 1.15 via zeta potential measurements. The hydrolytic degradation of p(L-Cys) particles was determined as about 85% within 3 h (by weight). The p(L-Cys) particles displayed excellent blood compatibility with a hemolysis % ratio of <2.3% and a blood clotting index of 95% at 1 mg/mL concentration. Moreover, cell compatibility tests up to 50 mg/mL against L929 fibroblast cells exhibited about 90% cell viability for p(L-Cys) particles versus 58% for L-Cys molecule. The antimicrobial efficacy of the L-Cys molecules was notably enhanced in p(L-Cys) particles, exhibiting a 5-fold reduction in minimal bactericidal concentration (MBC) values against E. coli (Gram-negative, ATCC 8739) and a 2-fold reduction against S. aureus (Gram-positive, ATCC 6538). Additionally, the antioxidant capacity of p(L-Cys) particles was retained somewhat, measured as 0.14 ± 0.01 µM versus 2.25 ± 0.03 µM Trolox equivalent/g for L-Cys. Therefore, p(L-Cys) particles are versatile and offer a unique avenue for immense biomedical use. Full article

Background: Submacular hemorrhage (SMH) is a vision-threatening condition most associated with neovascular age-related macular degeneration (nAMD), although it may also arise from polypoidal choroidal vasculopathy, pathological myopia, retinal vascular diseases, trauma, and systemic factors. Rapid management is essential because subretinal blood induces photoreceptor toxicity, clot organization, and fibroglial scarring, leading to irreversible visual loss. The choice and urgency of treatment depend on hemorrhage size, duration, and underlying pathology, and the patient’s surgical risk category, which can influence the invasiveness of the selected procedure. This review aims to provide an updated synthesis of recent advances in the surgical and pharmacological management of SMH, focusing on evidence from the past five years and comparing outcomes across major interventional approaches. Methods: A narrative review of 27 recent clinical and multicentre studies was conducted. The included literature evaluated pneumatic displacement (PD), pars plana vitrectomy (PPV), subretinal or intravitreal recombinant tissue plasminogen activator (rtPA), anti-VEGF therapy, and hybrid techniques. Studies were analyzed about indications, surgical methods, timing of intervention, anatomical and functional outcomes, and complication and patient risk stratification. Results: Outcomes varied depending on the size and duration of hemorrhage, as well as the activity of underlying macular neovascularization. PD with intravitreal rtPA was reported as effective for small and recent SMH. PPV combined with subretinal rtPA, filtered air, and anti-VEGF therapy demonstrated favorable displacement and visual outcomes in medium to large hemorrhages or those associated with active nAMD. Hybrid techniques further improved clot mobilization in selected cases. Across studies, delayed intervention beyond 14 days correlated with reduced visual recovery due to blood organization and photoreceptor loss. Potential risks, including recurrent bleeding and rtPA-associated toxicity, were reported but varied across studies. Conclusions: Management should be individualized, considering hemorrhage characteristics and surgical risk. Laser therapy, including PDT, may serve as an adjunct in the perioperative or postoperative period, particularly in PCV patients. Early, tailored intervention typically yields the best functional outcomes. Full article

A promising application of smart materials based on natural polymers is the potential to solve problems related to hemostasis in cases of severe bleeding caused by injury or surgery. This can be a life-threatening situation. Cellulose and its modified derivatives represent one of the most promising sources for creating effective hemostatic systems, as well as for various sensing applications related to disease detection, infection diagnosis, chronic condition monitoring, and blood analysis. The aim of this review was to identify key criteria for the efficiency of cellulose-based gels with hemostatic activity. Experimental studies aimed at evaluating new hemostatic devices were analyzed based on international sources using the PRISMA methodology. A total of 111 publications were identified. Following the identification and screening stages, 20 articles were selected for the final qualitative synthesis. The analyzed publications include experimental studies focused on the development and analysis of highly porous cellulose-based scaffolds in the form of aerogels and cryogels. The type and origin of cellulose, as well as the influence of additional components and synthesis conditions on gel formation, were investigated. Three major groups of key criteria that should be considered when developing new cellulose-based highly porous scaffolds with hemostatic functionality were identified: (I) physicochemical and mechanical properties (pore size distribution, compressive strength, and presence of functional groups); (II) in vitro tests (blood clotting index, red blood cell adhesion rate, hemolysis, cytocompatibility, and antibacterial activity); (III) in vivo hemostatic efficiency (hemostasis time and blood loss) in compliance with the 3Rs policy (replacement, reduction, refinement). The prospects for the development of highly porous cellulose-based scaffolds are not only focused on their hemostatic properties, but also on the development of smart platforms. Full article

Biomaterials derived from natural-origin polymers often lack the desired functionality and additional features, such as antibacterial properties, which could be beneficial in the design of modern wound dressings. Our research aimed to fabricate biosafe antibacterial dressings through the modification of curdlan-based hydrogels with triangle-shaped silver nanoparticles (AgTNPs) and poly(L-DOPA) (PL). The prepared hydrogels, including physicochemical, structural, biological, and antibacterial assessments, were thoroughly characterized. All formulations were confirmed to be non-toxic toward eukaryotic cells. The presence of PL in the hydrogels significantly reduced mortality in the zebrafish larvae model, highlighting the improved biocompatibility of the hydrogels. The three-component hydrogel (CUR-PL-AgT) demonstrated a high antibacterial effectiveness against Staphylococcus aureus and Pseudomonas aeruginosa. Additionally, the same three-component material outperformed a hydrogel containing only AgTNPs in promoting blood clot formation. Furthermore, PL enhanced the heat generating capability of hydrogels, showing their potential in medical applications where the temperature effects can stimulate biological processes of different natures. Full article

Background/Objectives: Menstrual blood, a periodic uterine discharge, represents a non-invasive source for an indication of the functional status of the endometrium. While menstrual blood-derived stem cells have been extensively characterized and menstrual blood is considered a diagnostic material for the analysis of gynecologic pathology in research studies, it is not routinely used in clinical settings. To develop novel noninvasive diagnostic tools for endometrial status assessment, we aimed to characterize the morphological and molecular markers of menstrual blood. Methods: Menstrual blood samples were obtained from healthy volunteers and characterized macroscopically and microscopically using smears (May-Grunwald-Giemsa staining), confocal microscopy, and imaging flow cytometry (cluster of differentiation [CD]90, CD45, fibrin). Clot dissociation was performed to analyze the cellular composition of clots. Results: We morphologically characterized menstrual blood cells and identified three uterine-derived cells and cell cluster types (endometrial stromal, endometrial epithelial, and vaginal epithelial). Additionally, we confirmed the specificity of CD90 for endometrial stromal cell populations, which were separately characterized in the supernatant and menstrual blood clots using light and confocal microscopy, and we analyzed the composition of the menstrual blood supernatant and dissociated clots using imaging flow cytometry. Conclusions: The results of this study may serve as a foundation for the development of new non-invasive diagnostic tools for endometrial pathology for the potential support or replacement of highly invasive procedures, such as diagnostic dilation and curettage. Full article

Vascular endothelium balances antithrombotic and anti-inflammatory activity to control blood vessel tone under physiological conditions. However, endothelial dysfunction impairs these processes, causing a state that promotes clotting and inflammation. Eicosanoids are a major class of bioactive lipid mediators crucial for modulating endothelial and platelet function. Research has highlighted the roles of eicosanoids in vascular diseases, showing pro-inflammatory, prothrombotic, and protective activities. Specifically, prostaglandin E₂ (PGE₂) is crucial because of its major role in atherosclerosis development and progression, acting via EP receptors involved in forming, maintaining, and stabilizing atherosclerotic lesions, thereby making PGE₂-EP signalling a specific target for treating cardiovascular diseases. This review will explore the evidence on eicosanoids and the role of their receptor modulation in platelet and vascular dysfunction in atherothrombosis. The studies included in this scoping review were retrieved from PubMed, Web of Science, Cochrane, and Scopus in accordance with the Preferred Reporting Items for Scoping Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) statement and the Population Intervention Comparison Outcome Population (PICO) framework. Eight clinical studies were found, which highlighted the crucial role of eicosanoids, like prostaglandins and their receptors, in endothelial and platelet dysfunction, and also how pharmacological mechanisms affect atherothrombosis. A new therapeutic approach for cardiovascular dysfunction is indicated by the recent findings, specifically against atherothrombosis, focusing on eicosanoids, their receptors, and processes like oxidative stress. Despite this evidence, there is a lack of comprehensive research results from scientific databases; therefore, further in vitro, in vivo, and clinical studies should be promoted to validate the preliminary results. Full article

Background/Objectives: The timely evaluation of blood clot formation and breakdown is essential in the care of patients with severe bleeding or critical illness. Resonant acoustic rheometry is a novel, non-contact ultrasound method that measures changes in the viscoelastic properties of blood in a standard microplate format. Here, we present the first clinical description of whole blood coagulation and fibrinolysis assessed with resonant acoustic rheometry, with paired thromboelastography measurements for comparison. Methods: In this retrospective analysis, whole blood samples from three critically ill patients were divided and tested under four different conditions that included a control mixture, kaolin activation, tissue factor activation, and a tissue factor mixture supplemented with tissue plasminogen activator. The resonant acoustic rheometry system obtained real time measurements of resonant surface waves and displacements from the samples. Heat maps and spectrograms of the resonant surface waves were analyzed to determine the onset of clotting, the rate of viscoelastic stiffening, the time to maximum rigidity, and the onset as well as magnitude of fibrinolysis. These measurements were compared with thromboelastography reaction time, clot strength, fibrinogen contribution, and lysis values. Results: Resonant acoustic rheometry detected reproducible transitions from liquid to clot and from clot to lysis in all samples. Activator-dependent changes in clot initiation and propagation matched the expected hierarchy observed in thromboelastography. Significantly, samples exposed to tissue plasminogen activator demonstrated a clear fall in resonant frequency and a corresponding rise in surface displacement that reflected fibrinolysis. The technique also reproduced clinically meaningful patterns of hemostasis that aligned with each patient’s underlying disease. Conclusions: Whole blood clotting can be measured with resonant acoustic rheometry in a manner that aligns with established clinical assays. These results suggest strong potential for future use of resonant acoustic rheometry as a cost-effective, complementary platform for rapid, scalable, and clinically informative hemostatic assessment. Full article

Tooth extraction induces changes in both hard and soft tissues, which may compromise implant placement. Leukocyte- and platelet-rich fibrin (L-PRF) is used to promote tissue healing, either alone or in combination with other grafting materials. Objective: This study aimed to compare post-extraction socket healing using L-PRF alone or combined with a biphasic calcium phosphate graft (HA/β-TCP) after eight weeks. Materials and Methods: 15 patients, both sexes, mean age 56.7 ± 8.2 years, requiring alveolar ridge preservation after single-rooted tooth extraction for subsequent implant placement, were included. Sockets were randomly assigned to four groups: control with blood clot only (CTR), autogenous bone graft (AB), L-PRF membrane (LPRF), and L-PRF combined with HA/β-TCP (LPRFHA). The protocol consisted of tooth extraction and immediate graft placement, followed by bone biopsy at 8 weeks for histomorphometric analysis and implant installation. New Bone Formation (NBF) was quantified from ten photomicrographs per sample using ImageJ software (version 1.54, 5 February 2025). One-way ANOVA with Bonferroni post hoc tests was applied, with statistical significance set at p ≤ 0.05. Results: A significant difference in NBF (%) was observed between the control and LPRFHA groups (p = 0.014), with greater bone formation in the control group (62.4 ± 18.6%) compared with LPRFHA (55.8 ± 17.2%; p = 0.012). No significant differences were found among AB, LPRF, and LPRFHA groups. LPRF and AB showed comparable bone formation (60.2 ± 17.5% and 60.1 ± 20.0%, respectively). Conclusions: L-PRF, either alone or combined with HA/β-TCP, can be used for alveolar ridge preservation in maxillary sockets. L-PRF, alone or with synthetic HA/β-TCP graft, effectively preserves the anterior maxillary ridge for early loading at eight weeks. All treatments achieved bone formation for implant placement, with the blood clot alone showing superior results. Full article

Fibrinolysis is a natural component of hemostasis in which a no-longer-needed clot is gradually dissolved to restore blood flow. Under pathological thrombotic conditions, this process can be pharmacologically enhanced to promote clot removal. However, thrombolytic therapy has limited efficacy and is associated with a risk of bleeding complications, including intracranial hemorrhage. Fibrinolysis targets only the fibrin-rich part of the thrombus, whereas a substantial fraction of the clot is enriched with non-fibrin components such as extracellular DNA, von Willebrand factor, and extracellular matrix proteins, including collagen, fibronectin, and laminin. These structural regions, which may constitute half or more of the clot volume, remain resistant to classical fibrinolytic agents. To overcome these limitations, recent therapeutic strategies aim to degrade these non-fibrin elements to improve thrombolytic efficacy and reduce adverse effects. In this review, we summarize current trends in pharmacological clot dissolution, discuss novel agents in clinical use and development, and outline how targeting non-fibrin components may influence the future of thrombolytic therapy. Full article

Immunothrombosis can substantially affect the course and outcomes of severe infections and immune-mediated diseases. While inflammatory thrombi are neutrophil-rich, impact of neutrophils on clot contraction, a key modulator of thrombus stability and obstructiveness, was unknown. This study investigated how neutrophils and neutrophil extracellular traps (NETs) affect the rate and extent of platelet-driven clot contraction. Isolated human neutrophils were stimulated with phorbol-12-myristate-13-acetate (PMA) to induce NETosis, confirmed by fluorescence microscopy and scanning electron microscopy. Thrombin-induced clots, formed from whole blood or platelet-rich plasma, were supplemented with non-activated or PMA-activated neutrophils. Clot contraction kinetics and viscoelasticity were analyzed. PMA-activated neutrophils significantly enhanced the rate and final extent of clot contraction compared to controls. This promoting effect was abolished by deoxyribonuclease (DNAse) I, confirming that it was mediated by NETs embedded in the fibrin network. The factor Xa inhibitor rivaroxaban also abrogated this effect, indicating a role for NET-induced endogenous thrombin generation and platelet hyperactivation. Thromboelastography revealed that NETs made clots softer and more deformable. We conclude that activated neutrophils promote clot contraction via NETs embedded in the fibrin network, which enhance platelet contractility via endogenous thrombin production and increase clot deformability, suggesting that inflammatory thrombosis may require treatments addressing this enhanced contractility. Full article

Haemonchus contortus is a blood-feeding gastrointestinal nematode that significantly impacts the health and productivity of small ruminants. The burden of parasitism and the escalating incidence of anthelmintic resistance necessitate alternative control methods. Here, we characterize the enzymatic activities of five mammalian cell-expressed recombinant H. contortus cysteine proteases (HcCPs), which include two cathepsin B-like proteins (HcCBP1 and HcCBP2) and three cysteine protease 1 proteins (HcCP1a, HcCP1b, and HcCP1c). We hypothesize that these enzymes degrade host blood proteins, thereby facilitating the parasite’s nutrient acquisition and survival. Using synthetic cathepsin (cat) substrates, we show that HcCBP2 was the only protein that exhibited high catB/L but low catB or catK activity, which was inhibited by the cysteine protease inhibitor E-64. All mHcCPs degraded fibrinogen (Fg), which led to delayed plasma clotting, reduced clot density, and lysed plasma clots. All HcCPs partially degraded hemoglobin (Hb), except for mHcCBP2, which degraded Hb and bovine serum albumin completely and bovine IgG partially in the presence of a reducing agent. In conclusion, by sustaining blood feeding and facilitating immune evasion and nutrient acquisition, the HcCPs may play an essential role in the parasite’s survival. Thus, vaccines or cysteine protease inhibitors targeting these parasitic enzymes may mitigate or prevent infections. Full article

Estrogen deficiency is a primary cause of osteoporosis, compromising bone mineral density that may impair peri-implant healing. Given the compromised bone environment associated with estrogen deficiency, strategies such as particle reduction via sonochemistry are promising approaches to enhance regenerative outcomes. However, its effects in promoting bone formation remain insufficiently explored. Therefore, this study evaluated the potential of two sonicated biomaterials to improve peri-implant repair in ovariectomized rats. Fifty female rats were allocated into five groups: blood clot (CLOT), Biogran^® (BGN), sonicated Biogran^® (BGS), Bio-Oss^® (BON), and sonicated Bio-Oss^® (BOS). Tibial peri-implant defects were created 30 days after ovariectomy and analyzed 28 days later by removal torque, microcomputed tomography, and confocal microscopy. BGS exhibited the highest removal torque (6.28 Ncm), followed by BON (5.37 Ncm), BOS (3.92 Ncm), BGN (3.15 Ncm), and CLOT (2.58 Ncm). Micro-CT revealed bone volume fraction (BV/TV) values of 8.07% (CLOT), 6.47% (BOS), 6.02% (BGS), 5.55% (BGN), and 2.84% (BON). For the trabecular number (Tb.N), BGS (1.11 mm⁻¹) showed a significant increase compared with BGN (0.69 mm⁻¹), p < 0.05. These findings show that sonochemically modified bioactive glass improves mechanical stability and trabecular microarchitecture under estrogen-deficient conditions. However, further studies are needed to standardize sonication parameters for different biomaterials and expand their translational applicability. Full article