Heparan sulfate-dependent phase separation of CCL5 and its chemotactic activity.

Secreted chemokines form concentration gradients in target tissues to control migratory directions and patterns of immune cells in response to inflammatory stimulation; however, how the gradients are formed is much debated. Heparan sulfate (HS) binds to chemokines and modulates their activities. In this study, we investigated the roles of HS in the gradient formation and chemoattractant activity of CCL5 that is known to bind to HS. CCL5 and heparin underwent liquid-liquid phase separation and formed gradient, which was confirmed using CCL5 immobilized on heparin-beads. The biological implication of HS in CCL5 gradient formation was established in CHO-K1 (wild-type) and CHO-677 (lacking HS) cells by Transwell assay. The effect of HS on CCL5 chemoattractant activity was further proved by Transwell assay of human peripheral blood cells. Finally, peritoneal injection of the chemokines into mice showed reduced recruitment of inflammatory cells either by mutant CCL5 (lacking heparin-binding sequence) or by addition of heparin to wild-type CCL5. Our experimental data propose that co-phase separation of CCL5 with HS establishes a specific chemokine concentration gradient to trigger directional cell migration. The results warrant further investigation on other heparin-binding chemokines and allows for a more elaborate insight into disease process and new treatment strategies.

Heparin is an effective treatment for preventing liver failure after hepatectomy.

BACKGROUND: Posthepatectomy liver failure (PHLF) is one of the most important causes of death following liver resection. Heparin, an established anticoagulant, can protect liver function through a number of mechanisms, and thus, prevent liver failure. AIM: To look at the safety and efficacy of heparin in preventing hepatic dysfunction after hepatectomy. METHODS: The data was extracted from Multiparameter Intelligent Monitoring in Intensive Care III (MIMIC-III) v1. 4 pinpointed patients who had undergone hepatectomy for liver cancer, subdividing them into two cohorts: Those who were injected with heparin and those who were not. The statistical evaluations used were unpaired t-tests, Mann-Whitney U tests, chi-square tests, and Fisher's exact tests to assess the effect of heparin administration on PHLF, duration of intensive care unit (ICU) stay, need for mechanical ventilation, use of continuous renal replacement therapy (CRRT), incidence of hypoxemia, development of acute kidney injury, and ICU mortality. Logistic regression was utilized to analyze the factors related to PHLF, with propensity score matching (PSM) aiming to balance the preoperative disparities between the two groups. RESULTS: In this study, 1388 patients who underwent liver cancer hepatectomy were analyzed. PSM yielded 213 matched pairs from the heparin-treated and control groups. Initial univariate analyses indicated that heparin potentially reduces the risk of PHLF in both matched and unmatched samples. Further analysis in the matched cohorts confirmed a significant association, with heparin reducing the risk of PHLF (odds ratio: 0.518; 95% confidence interval: 0.295-0.910; P = 0.022). Additionally, heparin treatment correlated with improved short-term postoperative outcomes such as reduced ICU stay durations, diminished requirements for respiratory support and CRRT, and lower incidences of hypoxemia and ICU mortality. CONCLUSION: Liver failure is an important hazard following hepatic surgery. During ICU care heparin administration has been proved to decrease the occurrence of hepatectomy induced liver failure. This indicates that heparin may provide a hopeful option for controlling PHLF.

Heparin-Induced Thrombocytopenia in Patients Suffering Cardiogenic Shock.

OBJECTIVES: Cardiogenic shock (CS) is associated with high mortality. Patients treated for CS mostly require heparin therapy, which may be associated with complications such as heparin-induced thrombocytopenia (HIT). HIT represents a serious condition associated with platelet decline and increased hypercoagulability and remains a poorly researched field in intensive care medicine. Primary purpose of this study was to: 1) determine HIT prevalence in CS, 2) assess the performance of common diagnostic tests for the workup of HIT, and 3) compare outcomes in CS patients with excluded and confirmed HIT. DESIGN: Retrospective dual-center study including adult patients 18 years old or older with diagnosed CS and suspected HIT from January 2010 to November 2022. SETTING: Cardiac ICU at the Ludwig-Maximilians University hospital in Munich and the university hospital of Bonn. PATIENTS AND INTERVENTIONS: In this retrospective analysis, adult patients with diagnosed CS and suspected HIT were included. Differences in baseline characteristics, mortality, neurologic and safety outcomes between patients with excluded and confirmed HIT were evaluated. MEASUREMENTS AND MAIN RESULTS: In cases of suspected HIT, positive screening antibodies were detected in 159 of 2808 patients (5.7%). HIT was confirmed via positive functional assay in 57 of 2808 patients, corresponding to a prevalence rate of 2.0%. The positive predictive value for anti-platelet factor 4/heparin screening antibodies was 35.8%. Total in-hospital mortality (58.8% vs. 57.9%; p > 0.999), 1-month mortality (47.1% vs. 43.9%; p = 0.781), and 12-month mortality (58.8% vs. 59.6%; p > 0.999) were similar between patients with excluded and confirmed HIT, respectively. Furthermore, no significant difference in neurologic outcome among survivors was found between groups (Cerebral Performance Category [CPC] score 1: 8.8% vs. 8.8%; p > 0.999 and CPC 2: 7.8% vs. 12.3%; p = 0.485). CONCLUSIONS: HIT was a rare complication in CS patients treated with unfractionated heparin and was not associated with increased mortality. Also, HIT confirmation was not associated with worse neurologic outcome in survivors. Future studies should aim at developing more precise, standardized, and cost-effective strategies to diagnose HIT and prevent complications.

Heparin-Induced Thrombocytopenia in Patients Suffering Cardiogenic Shock.

OBJECTIVES: Cardiogenic shock (CS) is associated with high mortality. Patients treated for CS mostly require heparin therapy, which may be associated with complications such as heparin-induced thrombocytopenia (HIT). HIT represents a serious condition associated with platelet decline and increased hypercoagulability and remains a poorly researched field in intensive care medicine. Primary purpose of this study was to: 1) determine HIT prevalence in CS, 2) assess the performance of common diagnostic tests for the workup of HIT, and 3) compare outcomes in CS patients with excluded and confirmed HIT. DESIGN: Retrospective dual-center study including adult patients 18 years old or older with diagnosed CS and suspected HIT from January 2010 to November 2022. SETTING: Cardiac ICU at the Ludwig-Maximilians University hospital in Munich and the university hospital of Bonn. PATIENTS AND INTERVENTIONS: In this retrospective analysis, adult patients with diagnosed CS and suspected HIT were included. Differences in baseline characteristics, mortality, neurologic and safety outcomes between patients with excluded and confirmed HIT were evaluated. MEASUREMENTS AND MAIN RESULTS: In cases of suspected HIT, positive screening antibodies were detected in 159 of 2808 patients (5.7%). HIT was confirmed via positive functional assay in 57 of 2808 patients, corresponding to a prevalence rate of 2.0%. The positive predictive value for anti-platelet factor 4/heparin screening antibodies was 35.8%. Total in-hospital mortality (58.8% vs. 57.9%; p > 0.999), 1-month mortality (47.1% vs. 43.9%; p = 0.781), and 12-month mortality (58.8% vs. 59.6%; p > 0.999) were similar between patients with excluded and confirmed HIT, respectively. Furthermore, no significant difference in neurologic outcome among survivors was found between groups (Cerebral Performance Category [CPC] score 1: 8.8% vs. 8.8%; p > 0.999 and CPC 2: 7.8% vs. 12.3%; p = 0.485). CONCLUSIONS: HIT was a rare complication in CS patients treated with unfractionated heparin and was not associated with increased mortality. Also, HIT confirmation was not associated with worse neurologic outcome in survivors. Future studies should aim at developing more precise, standardized, and cost-effective strategies to diagnose HIT and prevent complications.

Reduced Radial Artery Occlusion in Transradial Cerebral Angiography: Key Predictive Factors and Preventive Measures from a Single-Center Study of 543 Patients.

BACKGROUND The transradial approach (TRA) for cerebral angiography and neurointerventional treatment has gained popularity, but the narrow diameter and weak pulsation of the radial artery lower the initial puncture success rate compared to femoral artery puncture. This retrospective study from a single center evaluated the incidence of and factors associated with radial artery occlusion (RAO) in 543 patients who underwent transradial approach (TRA) for cerebral angiography. MATERIAL AND METHODS We included 543 patients who underwent TRA from July 2021 to February 2024. Ultrasound was used to determine whether the radial artery was occluded. Relevant clinical data were recorded to assess the incidence of and factors affecting RAO. RESULTS At 24 h after DSA, we performed ultrasound imaging. The patients were divided into an RAO group (n=32) and a non-RAO group (n=511). Results showed that RAO was significantly higher in patients who did not have add heparin to the antispasmodic agents, and they were more likely to have needed more than 3 radial artery puncture attempts, and tended to have received an 11-cm radial artery sheath with the Cordis puncture needles (all P<0.05). Multiple regression logistic analysis showed that adding heparin to the antispasmodic agents (OR=0.076, 95% CI: 0.018-0.321, P<0.001), having fewer than 3 radial artery puncture attempts (OR=0.245, 95% CI: 0.111-0.541, P<0.001), using a 16-cm radial artery sheath (OR=0.195, 95% CI: 0.067-0.564, P=0.003), and using Terumo puncture needles (OR=0.325, 95% CI: 0.148-0.717, P=0.005) can reduce the incidence of radial artery occlusion. CONCLUSIONS Our center found that adding heparin to the antispasmodic agents reduced the number of radial artery punctures attempts, and using a 16-cm radial artery sheath significantly lowered the incidence of early RAO after transradial cerebral angiography.

Identification of heparin-binding amino acid residues in antibody HS4C3 with the potential to design antibodies against heparan sulfate domains.

Heparan sulfate (HS) is a linear polysaccharide with high structural and functional diversity. Detection and localization of HS in tissues can be performed using single chain variable fragment (scFv) antibodies. Although several anti-HS antibodies recognizing different sulfation motifs have been identified, little is known about their interaction with HS. In this study the interaction between the scFv antibody HS4C3 and heparin was investigated. Heparin-binding lysine and arginine residues were identified using a protect and label methodology. Site-directed mutagenesis was applied to further identify critical heparin-binding lysine/arginine residues using immunohistochemical and biochemical assays. In addition, computational docking of a heparin tetrasaccharide towards a 3-D homology model of HS4C3 was applied to identify potential heparin-binding sites. Of the 12 lysine and 15 arginine residues within the HS4C3 antibody, 6 and 9, respectively, were identified as heparin-binding. Most of these residues are located within one of the complementarity determining regions (CDR) or in their proximity. All basic amino acid residues in the CDR3 region of the heavy chain were involved in binding. Computational docking showed a heparin tetrasaccharide close to these regions. Mutagenesis of heparin-binding residues reduced or altered reactivity towards HS and heparin. Identification of heparin-binding arginine and lysine residues in HS4C3 allows for better understanding of the interaction with HS and creates a framework to rationally design antibodies targeting specific HS motifs.

The association between heparin sensitivity index and postoperative blood loss in Chinese patients undergoing elective off-pump coronary artery bypass grafting: a single center retrospective study.

BACKGROUND: The heparin sensitivity index (HSI) is closely associated with perioperative ischemic events and increased blood loss in cardiac surgery. Previous studies have produced conflicting results. Therefore, this study aimed to investigate the relationship between HSI and postoperative blood loss specifically in Chinese patients undergoing elective off-pump coronary artery bypass grafting (OPCAB). METHODS: Patients underwent OPCAB between March 2021 and July 2022 were retrospectively included. Enrolled patients were classified into Low-HSI (HSILOW; HSI < 1.3) and Normal-HSI (HSINORM; HSI ≥ 1.3) groups. HSI = [(activated clotting time (ACT) after heparin) - (baseline ACT)] / [loading dose of heparin (IU/kg)]. Primary outcome included postoperative blood loss at 24 h. Secondary outcomes were total postoperative blood loss, transfusion requirement of red blood cell (RBC), fresh frozen plasma (FFP), platelet concentrates (PC), and other complications. RESULTS: We retrospectively analyzed 303 Chinese OPCAB patients. HSILOW group had higher preoperative platelet (PLT) count (221 × 109/L vs. 202 × 109/L; P = 0.041) and platelet crit (PCT) value (0.23% vs. 0.22%; P = 0.040) compared to HSINORM group. Two groups showed no significant differences in postoperative blood loss at 24 h (460 mL vs. 470 mL; P = 0.252), total blood loss (920 mL vs. 980 mL; P = 0.063), RBC transfusion requirement (3.4% vs. 3.1%; P = 1.000), FFP transfusion requirement (3.4% vs. 6.2%; P = 0.380), and other complications. Preoperative high PLT count was associated with low intraoperative HSI value (odds ratio: 1.006; 95% confidence interval: 1.002, 1.011; P = 0.008). CONCLUSIONS: Intraoperative HSI value was not associated with postoperative blood loss in Chinese patients undergoing OPCAB. Preoperative high PLT count was an independent predictor of low intraoperative HSI value.

Preventing adverse events during paediatric cancer treatment: protocol for a multi-site hybrid randomised controlled trial of catheter lock solutions (the CLOCK trial).

INTRODUCTION: Central venous access devices (CVADs) are commonly used for the treatment of paediatric cancer patients. Catheter locking is a routine intervention that prevents CVAD-associated adverse events, such as infection, occlusion and thrombosis. While laboratory and clinical data are promising, tetra-EDTA (T-EDTA) has yet to be rigorously evaluated or introduced in cancer care as a catheter lock. METHODS AND ANALYSIS: This is a protocol for a two-arm, superiority type 1 hybrid effectiveness-implementation randomised controlled trial conducted at seven hospitals across Australia and New Zealand. Randomisation will be in a 3:2 ratio between the saline (heparinised saline and normal saline) and T-EDTA groups, with randomly varied blocks of size 10 or 20 and stratification by (1) healthcare facility; (2) CVAD type and (3) duration of dwell since insertion. Within the saline group, there will be a random allocation between normal and heparin saline. Participants can be re-recruited and randomised on insertion of a new CVAD. Primary outcome for effectiveness will be a composite of CVAD-associated bloodstream infections (CABSI), CVAD-associated thrombosis or CVAD occlusion during CVAD dwell or at removal. Secondary outcomes will include CABSI, CVAD-associated-thrombosis, CVAD failure, incidental asymptomatic CVAD-associated-thrombosis, other adverse events, health-related quality of life, healthcare costs and mortality. To achieve 90% power (alpha=0.05) for the primary outcome, data from 720 recruitments are required. A mixed-methods approach will be employed to explore implementation contexts from the perspective of clinicians and healthcare purchasers. ETHICS AND DISSEMINATION: Ethics approval has been provided by Children's Health Queensland Hospital and Health Service Human Research Ethics Committee (HREC) (HREC/22/QCHQ/81744) and the University of Queensland HREC (2022/HE000196) with subsequent governance approval at all sites. Informed consent is required from the substitute decision-maker or legal guardian prior to participation. In addition, consent may also be obtained from mature minors, depending on the legislative requirements of the study site. The primary trial and substudies will be written by the investigators and published in peer-reviewed journals. The findings will also be disseminated through local health and clinical trial networks by investigators and presented at conferences. TRIAL REGISTRATION NUMBER: ACTRN12622000499785.

Protamine and Heparin Interactions: A Narrative Review.

ABSTRACT: Protamine, first isolated from salmon fish sperm and now produced through recombinant biotechnology, is an antidote that neutralizes the anticoagulant properties of heparin. Protamine function is based on the capacity to dissociate the heparin-antithrombin III (AT III) complex (an important link that promotes blood fluidification by inhibiting coagulation), forming the inactive heparin-protamine complex. Protamine has itself dose-dependent anticoagulant properties: It interferes with coagulation factors and platelet function; it stimulates fibrinolysis; it can lead to thrombocytopenia and reduction in thrombin-related platelet aggregation; it decreases platelet response to thrombin receptor agonist in a dose-dependent manner. In this review, we will focus on protamine and its interaction with heparin. Notably, protamine is able to antagonize not only unfractionated heparin (UFH) but also low molecular weight heparins to various degrees. Protamine-allergic and anaphylactoid systemic reactions may affect up to 1 in 10 people and should be prevented and treated early.

Analysis of arterial blood gas values when discarding different volumes of blood samples in an arterial heparin blood collector during thoracoscopic surgery.

BACKGROUND: Arterial blood gas analysis (ABGA) plays a vital role in emergency and intensive care, which is affected by many factors, such as different instrumentation, temperature, and testing time. However, there are still no relevant reports on the difference in discarding different blood volumes on ABGA values. METHODS: We enrolled 54 patients who underwent thoracoscopic surgery and analysed differences in blood gas analysis results when different blood volumes were discarded from the front line of the arterial heparin blood collector. A paired t test was used to compare the results of the same patient with different volumes of blood discarded from the samples. The difference was corrected by Bonferroni correction. RESULTS: Our results demonstrated that the PaO2, PaCO2, and THbc were more stable in the 4th ml (PaO2 = 231.3600 ± 68.4878 mmHg, PaCO2 = 41.9232 ± 7.4490 mmHg) and 5th ml (PaO2 = 223.7600 ± 12.9895 mmHg, PaCO2 = 42.5679 ± 7.6410 mmHg) blood sample than in the 3rd ml (PaO2 = 234.1000 ± 99.7570 mmHg, PaCO2 = 40.6179 ± 7.2040 mmHg). CONCLUSION: It may be more appropriate to discard the first 3 ml of blood sample in the analysis of blood gas results without wasting blood samples.

Fault in Our Genes: A Case of Pulmonary Thromboembolism in Young.

Methylenetetrahydrofolate reductase (MTHFR) enzyme is one of the key enzymes involved in the metabolism of folate. Mutations in this enzyme can lead to a procoagulant state. We present a case of a 20-year-old male with no known comorbidities, who presented with fever and hemoptysis and was diagnosed as a case of pulmonary embolism. He was found to have a homozygous mutation in the MTHFR gene that was responsible for his disease state. He was started on unfractionated heparin infusion and underwent catheter-directed thrombolysis. He showed marked improvement in his condition and was discharged on oral anticoagulants with an advice to follow-up.

RésuméL'enzyme méthylènetétrahydrofolate réductase (MTHFR) est l'une des enzymes clés impliquées dans le métabolisme du folate. Les mutations de cette enzyme peuvent conduire à un état procoagulant. Nous présentons le cas d'un homme de 20 ans sans comorbidités connues, qui s'est présenté avec de la fièvre et une hémoptysie et a été diagnostiqué comme un cas d'embolie pulmonaire. Il s'est avéré qu'il présentait une mutation homozygote du gène MTHFR responsable de son état pathologique. Il a commencé une perfusion d'héparine non fractionnée et a subi une thrombolyse dirigée par cathéter. Il a montré une nette amélioration de son état et a été libéré sous anticoagulants oraux avec un conseil de suivi.

[Heparin Resistance After Administration of Andexanet Alfa:Report of a Case].

The management of patients on direct oral anticoagulants (DOACs) who require an emergency cardiac surgery has been disputed in Japan. Recently, the use of andexanet alfa as an antidote for apixaban and rivaroxaban, is approved in the setting of life-threating or uncontrollable major bleeding. However, the efficacy and safety of andexanet alfa have been investigated. We report a case of 72-year-old man taking rivaroxaban who required the emergency coronary artery bypass grafting. He received andexanet alfa prior to the operation. Heparin resistance was noted before starting cardiopulmonary bypass. Consideration should be given to the use of andexanet alfa before or during cardiopulmonary bypass.

Heparin as a Potential Therapeutic Substance for Post-Traumatic Stress Disorder.

In sexually mature male Wistar rats with modeled post-traumatic stress disorder, personalized characteristics of neurobiological reactions in the population of predator-induced stress-resilient and stress-susceptible heparinized animals were determined. Characteristics of the systemic response of immune mechanisms, hypothalamic-pituitary-adrenal axis, behavioral manifestations, as well as basic properties of the CNS (excitation/inhibition) are presented. The study demonstrated encouraging positive results of the course administration of unfractionated heparin at a dose below the therapeutic and prophylactic doses. The inclusion of heparin drugs into the clinical practice for the treatment of post-traumatic stress disorder will not require large-scale clinical trials, because many effects of heparin as a nonspecific adaptogen are well studied. Moreover, these properties were confirmed at a higher technological level during the COVID-19 pandemic.

The Effects of Different Blood Sample and Anticoagulant Types on Quantitative Tests of B-Type Natriuretic Peptide.

BACKGROUND: BNP is a sensitive and widely used biomarker for an early diagnosis of heart failure. Currently, most commercial BNP detection products use EDTA plasma samples. The aim of this study was to evaluate the clinical performance of the BNP test by using whole blood samples compared to plasma samples, and to evaluate the effect of the anticoagulant type on the BNP test result. METHODS: In total, 106 patients with different BNP levels from the Dahua Hospital volunteered for this study. Clinically homogenous samples, including EDTA anticoagulant plasma, EDTA whole blood, and heparin anticoagulant plasma, were collected and analyzed by using i-Reader S automatic immuno-analyzer and its supporting reagent kits. Pearson's correlation and weighted least squares linear regression analysis, Bland-Altman plotting, and Kappa test were used for statistical analysis. RESULTS: Correlation analysis showed that BNP concentrations, measured from EDTA anticoagulated plasma samples, had a good linear regression relationship with BNP from whole blood samples, with a slope of 0.9477, r = 0.9978, p < 0.05. A similar correlation was observed between EDTA anticoagulated plasma samples and heparin anticoagulant plasma, with a slope of 0.8413, r = 0.9793, p < 0.05. The BNP concentration measured from the heparin plasma samples were lower than of the EDTA plasma samples. Bland-Altman analysis for assessing BNP concentration agreement showed there was no outlier ratio between EDTA whole blood and EDTA plasma within the range of the detection system, as well as no outlier between EDTA anticoagulated and heparin anticoagulant plasma. Kappa coefficient of BNP concentration between homologous EDTA anticoagulated and heparin anticoagulant plasma was 0.8553 (p < 0.001), and for EDTA anticoagulated plasma and homologous whole blood it was 0.8941 (p < 0.001). CONCLUSIONS: The diagnostic performance of EDTA anticoagulated whole blood samples did not differ significantly from EDTA anticoagulated plasma samples for the BNP test. This study showed no big significant difference between EDTA anticoagulated and heparin anticoagulated plasma measurements within 2 hours. The type of anticoagulant should be carefully chosen when performing the BNP test if BNP samples were in vitro for a long time.

Overview of the current procedures in synthesis of heparin saccharides.

Natural heparin, a glycosaminoglycan consisting of repeating hexuronic acid and glucosamine linked by 1 â†’ 4 glycosidic bonds, is the most widely used anticoagulant. To subvert the dependence on animal sourced heparin, alternative methods to produce heparin saccharides, i.e., either heterogenous sugar chains similar to natural heparin, or structurally defined oligosaccharides, are becoming hot subjects. Although the success by chemical synthesis of the pentasaccharide, fondaparinux, encourages to proceed through a chemical approach generating homogenous product, synthesizing larger oligos is still cumbersome and beyond reach so far. Alternatively, the chemoenzymatic pathway exhibited exquisite stereoselectivity of glycosylation and regioselectivity of modification, with the advantage to skip the tedious protection steps unavoidable in chemical synthesis. However, to a scale of drug production needed today is still not in sight. In comparison, a procedure of de novo biosynthesis in an organism could be an ultimate goal. The main purpose of this review is to summarize the current available/developing strategies and techniques, which is expected to provide a comprehensive picture for production of heparin saccharides to replenish or eventually to replace the animal derived products. In chemical and chemoenzymatic approaches, the methodologies are discussed according to the synthesis procedures: building block preparation, chain elongation, and backbone modification.

Therapeutic Potentials of Medicinal Leech in Chinese Medicine.

The use of medicinal leeches in clinical therapy has been employed for a long time, as it was originally recognized for exerting antithrombin effects. These effects were due to the ability of the leech to continuously suck blood while attached to human skin. According to Chinese Pharmacopoei, leeches used in traditional Chinese medicine mainly consist of Whitmania pigra Whitman, Hirudo nipponia Whitman, and Whitmania acranulata, but the latter two species are relatively scarce. The main constituents of leeches are protein and peptide macromolecules. They can be categorized into two categories based on their pharmacological effects. One group consists of active ingredients that directly target the coagulation system, such as hirudin, heparin, and histamine, which are widely known. The other group comprises protease inhibitor components like Decorsin and Hementin. Among these, hirudin secreted by the salivary glands of the leech is the most potent thrombin inhibitor and served as the sole remedy for preventing blood clotting until the discovery of heparin. Additionally, leeches play a significant role in various traditional Chinese medicine formulations. In recent decades, medicinal leeches have been applied in fields including anti-inflammatory treatment, cardiovascular disease management, antitumor treatment, and many other medical conditions. In this review, we present a comprehensive overview of the historical journey and medicinal applications of leeches in various medical conditions, emphasizing their pharmaceutical significance within traditional Chinese medicine. This review offers valuable insights for exploring additional therapeutic opportunities involving the use of leeches in various diseases and elucidating their underlying mechanisms for future research.

Distinct antithrombin activation modes for fondaparinux and natural heparins detected using millisecond hydrogen deuterium exchange and collision induced unfolding.

Low molecular weight heparin and synthetic mimetics such as fondaparinux show different binding kinetics, protease specificity, and clinical effects. A combination of allosteric and template-mediated bridging mechanisms have been proposed to explain the differences in rate acceleration and specificity. The difficulty in working with heterogeneous heparin species has rendered a crystallographic interpretation of the differences in antithrombin activation between mimetics and natural heparin inaccessible. In this study, we examine the allosteric changes in antithrombin caused by binding fondaparinux, enoxaparin and depolymerized natural heparins using millisecond hydrogen deuterium exchange mass spectrometry (TRESI-HDX MS) and relate these conformational changes to complex stability in the gas phase using collision induced unfolding (CIU). This exploration reveals that in addition to the dynamic changes caused by fondaparinux, long chain heparins reduce structural flexibility proximal to Arg393, the cleavable residue in the reactive centre loop of the protein. These local changes in protein dynamics are associated with an increase in overall complex stability that increases with heparin chain length. Ultimately, these results shed light on the molecular mechanisms underlying differences in activity and specificity between heparin mimetics and natural heparins.

Design of "Off-On-Off" fluorescence sensors for Heparin detection by precise modulation of molecular structure.

In this strategy, the fluorescence sensor Nap-Co-T1 employing the fluorescence resonance energy transfer (FRET) mechanism was designed and synthesized to have an efficient response to Heparin, and the FRET mechanism was explored for different excitation-emission wavelengths with different distances between the energy acceptor and the energy donor (comparing with fluorescence sensor Nap-TPA-T2). Upon the addition of Heparin, the fluorescence emission of Nap-Co-T1 was turned on at 565 nm, and the fluorescence color changed of the solution from colorless to bright yellow. The limit of detection (LOD) was as low as 0.04 µg/mL. With the addition of antagonistic protamine (PRTM) to the sensor complex with Heparin, the fluorescence emission was turned off to a certain extent, and the reversibility of the "off-on-off" system was maintained for five cycles or more. In addition, Nap-Co-T1 provides rapid and sensitive detection of Heparin in human serum albumin solution and artificial urine and is highly sensitive to environmental viscosity.