Pharmacology of Heparin and Related Drugs: An Update

Tricarbonylrhenium(I) complexes with aggregation-induced phosphorescence emission (AIPE) properties: Application to the selective detection of heparin and its main contaminant

Phosphorescent tricarbonylrhenium(I) complexes that are more emissive in the aggregate state than in solution could be very valuable probes for biological analyses, but their development is delicate. The present work focuses on the synthesis and spectroscopic study of three new complexes that differ by the nature of their positively charged substituent. The dissolved complexes were very weakly emissive. Due to electrostatic interaction and aggregation, they showed a strong aggregation-induced phosphorescence enhancement (AIPE) effect in the presence of heparin, a polyanionic macromolecule of biological interest, and a weaker effect in the presence of chondroitin sulfate, which contains fewer negative charges. The magnitude of the AIPE effect depended on the nature and number of the cationic groups borne by the complex. However, it was weaker than expected from the behavior of the parent neutral complex studied in a conventional acetonitrile/water system, which highlights the challenge of accurately predicting solid-state emission properties for this class of molecules. This work introduces rhenium(I) complexes in the field of AIPE-active probes for the detection of polyanionic biomolecules.

Rationally designed chemoenzymatic synthesis of heparan sulfate oligosaccharides with neutralizable anticoagulant activity and low severe complications

The identification of enzymes involved in biosynthesis of heparan sulfate (HS) and heparin and their successful application in chemoenzymatic synthesis have provided great impetus to rationally design well-defined oligosaccharides as ideal alternatives to animal-derived heterogeneous heparin anticoagulants clinically to treat clotting disorders. Herein, we revisited the substrate specificity of recombinant 2-O-sulfotransferases produced in different expression systems for the highly efficient chemoenzymatic synthesis of HS oligosaccharides containing the rare 2-O-sulfated GlcA (GlcA2S) residues, followed by further assembly into the highly sulfated HS dodecasaccharide (12-mer) and decasaccharide (10-mer) containing the antithrombin-binding domain and the trisulfated disaccharide (GlcA2S-GlcNS6S) units rarely found in natural heparin. The GlcA2S-containing HS 10-mer demonstrated both the effectively reversible anticoagulant activity similar to that of unfractionated heparin and the lower potential risk for life-threatening heparin-induced thrombocytopenia compared with enoxaparin, indicating its promising prospect as the next-generation HS/heparin-like anticoagulant therapeutics.

A review of technical steps in the performance of arteriovenous fistula creation

Although it is accepted that a functional arteriovenous fistula (AVF) is the optimal vascular access for dialysis, achieving function is difficult as the outcomes of AVF creation are sub-optimal. Many technical steps have been proposed to improve outcomes, but the strength of evidence to support these is unclear. Thus, a systematic review of all randomised controlled trials (RCT) of operative strategies to optimise AVF outcomes was performed to summarise the evidence, review the overall level of standardisation in RCT and thus determine if there was an objective basis for the technical steps in AVF creation. A systematic review of all RCT was performed and studies categorised by intervention type. The rationale for each intervention, outcomes and limitations were described. Most importantly, the completeness of reporting procedural steps was compared for all RCT and the therapeutic impact considered by AVF site. Of 6741 records meeting the search criteria, 31 RCT were included. Most RCT did not control for all technical aspects or fully detail the operative methods, with a mean of 4 technical steps not reported for which other RCT have been performed. Of studies involving a surgical intervention in RCF, 10/13 reported a significant benefit compared to only 5/15 studies in BCF or larger vessels. Overall, the adequacy of reporting the technical details in all RCT of technical steps in AVF creation was poor. Despite this, there was a consistent patency benefit found in RCT performed in smaller vessels although the extent of interaction between these is uncertain. There remain gaps in the literature in defining the optimal steps in fistula creation that, if confirmed, could significantly improve AVF outcomes. This makes it essential that future studies of novel techniques, such as percutaneous AVF creation, incorporate a standardised operating procedure of optimal current practice of surgically created AVF as a meaningful comparator.

An Aggregation-Induced Room Temperature Phosphorescence Probe for the Efficient and Selective Detection of Heparin and Protamine

Heparin is a vital macromolecule that regulates blood coagulation, while protamine is an essential polypeptide clinically used to counteract heparin overdose. Detecting both heparin and its antidote protamine under physiological conditions is crucial for biological and clinical applications. This report introduces a cucurbituril[8] (CB[8])-based phosphorescent probe for their detection. The method employs a nanoassembly induced phosphorescence switch-on mechanism for heparin sensing and a disassembly induced phosphorescence switch-off approach for protamine detection. An arginine-rich guest forms a supramolecular complex with heparin, enhancing phosphorescence under secondary confinement and enabling its detection. Conversely, protamine sulfate, as a stronger competitor for heparin, disrupts the probe-heparin aggregates, leading to emission quenching and protamine sensing. This sensor demonstrated high selectivity in detecting both analytes in biological samples, such as human blood serum and urine. The detection limits for heparin and protamine were determined to be 61 and 82 ng/mL in 10% HBS, respectively.

Cationic liposomes as broad-spectrum antidotes for heparin-based anticoagulants

Heparin-based anticoagulants have been widely used for the prevention and treatment of venous thrombotic diseases, as well as for anticoagulation during cardiopulmonary bypass and hemodialysis. However, excessive heparin usage brings serious bleeding risk, necessitating immediate reversal of their anticoagulant activity. Additionally, to prevent bleeding during surgery and restore hemostatic function post-cardiopulmonary bypass and hemodialysis, it is also crucial to reverse heparin's anticoagulant effects. Currently, protamine sulfate (PS) is the only clinically approved antidote for heparin. However, its effectiveness against low molecular weight heparin (LMWH) and fondaparinux sodium is limited. Moreover, PS has great potential to trigger fatal allergic reactions. Despite these concerns, no successful clinical substitutes for PS have been developed. In the current work, drawing inspiration from the mechanism by which PS efficiently reverses heparin, we modified the cationic liposome with cationic amino acids, arginine and lysine, to serve as a broad-spectrum antidote (CRKRK-Lipo) for heparin-based anticoagulants. This modification not only enhances their reversal efficiency but also reduces the overall surface charge, potentially improving their biocompatibility. In the tail bleeding and liver injury mouse models, CRKRK-Lipo demonstrated reversal efficiency comparable to PS for heparin and superior reversal efficiency for LMWH and fondaparinux sodium. Notably, CRKRK-Lipo exhibited a wider therapeutic dose window and did not exhibit severe cytotoxicity or immunogenicity, in contrast to PS. It is worth noting that cationic liposomes without polypeptide modification also displayed a significant heparin reversal effect. Our findings not only offer a potential alternative for PS but also broaden the application fields of cationic liposome. STATEMENT OF SIGNIFICANCE: This study introduces the cationic liposomes as a novel and effective alternative to protamine sulfate (PS) for the functional reversal of heparin-based anticoagulants. The results reveal that both CRKRK-modified cationic liposomes (CRKRK-Lipo) and unmodified cationic liposomes (Lipo) showed comparable reversal efficiency to PS for UFH and superior reversal efficiency for LMWH and fondaparinux sodium, with a wider therapeutic dose window and reduced toxicity. This work offers an alternative strategy for detoxifying heparin-based anticoagulants and expands the biomedical applications of cationic liposomes.

Novel composite bone cement modulates inflammatory response in vitro

1. To evaluate the anti-inflammatory properties of enoxaparin sodium polymethylmethacrylate bone cement within the indirect co-culture model comprising endothelial cells and macrophages. 2. To investigate the impacts of inflammatory factors IL-6 and IL-10 on macrophage M2 polarisation and endothelial cell apoptosis. An indirect co-culture system of endothelial cells and macrophages was established by utilizing 1 µg/mL of lipopolysaccharide (LPS) to trigger an inflammatory response model. The experiment was categorized into 4 groups: blank control group, LPS-indicated group, PMMA + LPS group, and ES-PMMA + LPS group. Flow cytometry was performed to ascertain the apoptosis rate of endothelial cells and macrophage polarisation trend in the co-culture system. Meanwhile, ELISA, Western blotting, and immunofluorescence were adopted to measure the expression levels of Interleukin-6(IL-6), Tumour Necrosis Factor-α(TNF-α), Intercellular Cell Adhesion Molecule (ICAM), and Interleukin-10(IL-10) in cells and supernatants. In the detection of two typical polarisation proteins, CD86 and CD206, it was observed that the expression level of the CD86 protein, which indicates M1 polarisation, was elevated in the LPS-induced group in comparison to the blank control group (**P < 0.01). The expression level was found to be down-regulated in the ES-PMMA + LPS group (*P < 0.05). In contrast, the expression level of CD206 protein, which indicates the trend of M2-polarisation, was observed to be down-regulated in the LPS-induced group compared to the blank control group (***P < 0.001). Conversely, this expression level was up-regulated in the ES-PMMA + LPS group in comparison to the LPS-induced group (**P < 0.01). The expression of IL-6, TNF-α, IL-10, and ICAM was investigated in cell culture supernatants using the Elisa assay. The results showed that the LPS-induced group had higher levels of IL-6, TNF-α, and ICAM compared to the blank control group (***P < 0.001), while the LPS-induced group had lower levels of IL-10 (***P < 0.001). Additionally, the ES-PMMA + LPS-induced group showed lower levels of the aforementioned cytokines (**P < 0.01 or *P < 0.05) and higher levels of IL-10 (*P < 0.05). Western Blot and immunofluorescence results revealed that the expression of IL-6, TNF-α, and ICAM was up-regulated (***P < 0.001) and IL-10 was down-regulated (***P < 0.001) in the LPS-induced group compared with the blank control group. Compared with the LPS-induced group and PMMA + LPS group, in the ES-PMMA + LPS group, the expression of all three proteins was down-regulated (*P < 0.05 or **P < 0.01), whereas the expression of the IL-10 protein was up-regulated (***P < 0.001). The inflammatory proteins IL-6, TNF-α, and ICAM were shown to have higher fluorescence intensity in the LPS-induced group compared to the blank control group (***P < 0.001), the intensity of IL-10 was observed to be diminished (***P < 0.001). In contrast, the fluorescence intensity of IL-6, TNF-α, and ICAM was reduced in the ES-PMMA + LPS group relative to the LPS-induced group (***P < 0.001), the intensity of IL-10 was enhanced (***P < 0.001). In terms of endothelial cell apoptosis rate detection, the rate of apoptosis considerably reduced in the ES-PMMA + LPS-induced group when compared to the LPS-induced group (***P < 0.001) and rose noticeably in the LPS-induced group when compared to the blank control group (***P < 0.001). (1) In the co-culture system, ES-PMMA bone cement fulfills anti-inflammatory functions by impeding the expression of inflammatory factor IL-6 and promoting IL-10. (2) ES-PMMA bone cement facilitates the M2 polarisation response of macrophages and declines endothelial cell apoptosis within a co-culture system. (3) ES-PMMA bone cement can modify the local inflammatory environment by modulating the expression of inflammatory factors, which is potentially valuable for the application of cement-related surgery.

Quaternized Fe3O4@chitosan nanoparticles for efficient and selective isolation of heparin

Heparin, a highly sulfated polysaccharide, is industrially produced for clinical applications. To realize highly efficient and selective adsorption of heparin from complex biological components (e.g., proteins, nucleic acids) remains a challenge in the isolation process. This study reported a simple and green approach to fabricate heparin adsorbent of quaternized Fe3O4@chitosan nanoparticles (QFCNs) by using the natural polysaccharides of chitosan coated and cross-linked with glutaraldehyde on the Fe3O4 and further quaternized using glycidyltrimethylammonium chloride. The effects of adsorbent type, pH, initial heparin concentration, and temperature on the adsorption performance were investigated. The QFCNs demonstrated a high adsorption efficiency of 90.02 % and a remarkable adsorption capacity of 33.04 mg g-1, surpassing the performance of previously reported adsorbents, and the adsorption process was found to be more closely aligned with the pseudo-first-order model, Langmuir and Sips isotherm model. Furthermore, the QCNFs exhibited a distinct selectivity for heparin in the presence of BSA at pH 7.0 in 0.3 mol L-1 of NaCl. The adsorption capacity of QFCNs was 1.63 times that of the commercial Amberlite FPA98Cl resin in the adsorption process of crude heparin, and the purity of the crude heparin was enhanced from 37.10 % to 78.10 %. Besides, the adsorption capacity remained at an acceptable level after five cycles. The X-ray photoelectron spectroscopy results elucidated the heparin adsorption follows the mechanism of the electrostatic attraction with the quaternary ammonium groups of QCNFs. QFCNs could become an ideal adsorbent for the selective capture of heparin and other negatively charged natural polysaccharides, offering high efficiency, environmental friendliness, and facile recyclability.

The Effect of Heparin on Bone Metabolism and Orthodontic Tooth Movement in Rats

OBJECTIVES

Various attempts have been made to increase the rate of orthodontic tooth movement (OTM). The aim of this study was to determine the effect of different doses of heparin on OTM and paraclinical factors related to bone metabolism in rats.

METHODS AND MATERIALS

A total of 24 Sprague-Dawley rats were randomly divided into three groups of 8 animals each and injected with 0 (control), 3000, and 6000 U/Kg/d heparin sulfate for 4 weeks. Radiographs were obtained at the initiation and at the end of the study period. Orthodontic forces were applied on Day 14 and continued for the next 2 weeks, after which, OTM, optical density, parathyroid hormone (PTH) level, and histologic variables were assessed for each rat. The latter was performed on hematoxylin/eosin-stained sections of the mesial roots of the first molar and included calculation of the osteoclast number, and resorption lacunae depth and number. One-way analysis of variance, the Tukey test, and a paired-t-test were used for statistical analysis (p < 0.05).

RESULTS

A significant increase in OTM, the number of resorptive lacunae, and PTH secretion was observed in the group that received 6000 U/Kg/d compared with both the other groups. There was no significant difference in optical density, and, therefore, bone density, among the study groups (p > 0.05).

CONCLUSION

Heparin injection affects bone metabolism in rats, as shown by the increases in OTM and PTH and its impact on histologic parameters. These effects seem to be dose-dependent and may be a factor that should be taken into consideration during orthodontic treatment planning.

The structural features and anti-inflammatory properties of a glucogalactan from Holotrichia diomphalia Bates (Qi Cao)

ETHNOPHARMACOLOGICAL RELEVANCE

The dried larvae of Holotrichia diomphalia Bates, named Qi Cao, is a traditional Chinese medicine treat for liver diseases and arthritis. Polysaccharides is a principal component in Qi Cao, which exhibiting antioxidant and anti-inflammatory effects. However, the structural characteristics and underlying mechanisms of the polysaccharides remain inadequately elucidated.

AIM OF THE STUDY

To analyze the primary structure and elucidate the molecular anti-inflammatory mechanisms of the active polysaccharide in Qi Cao.

MATERIALS AND METHODS

The total polysaccharide was extracted by water extraction and alcohol precipitation, and further isolated and purified by DEAE Sephadex A-25 column and Sephadex G-100 column. The anti-inflammatory properties of four major fractions (HDPS-1, HDPS-2, HDPS-3, HDPS-4) and the pure homogeneous polysaccharides (HDPS-1I and HDPS-1II) were assessed using a RAW 264.7 cell model induced by lipopolysaccharide (LPS), and HDPS-1II was identified as the polysaccharide exhibiting significant anti-inflammatory activity in Qi Cao. The structural characteristics of HDPS-1II were subsequently analyzed using high-performance size-exclusion chromatography (HPSEC), fourier-transform infrared spectroscopy (FT-IR), gas chromatography-mass spectrometry (GC-MS), and nuclear magnetic resonance (NMR) spectroscopy. The TLR4, NF-κB, COX-2 and iNOS expressions were determined by Western blot analysis to investigate the anti-inflammatory mechanism of HDPS-1II in vitro. Finally, the in vivo anti-inflammatory activity of HDPS-1II were evaluated by measuring the serum levels of pro-inflammatory factors, inflammatory cell infiltration and organelle damage in the lung tissues of sepsis model mice.

RESULTS

A homogeneous polysaccharide (HDPS-1II) with molecular weight of 1.7 × 104 Da was isolated from Holotrichia diomphalia Bates. HDPS-1II contains a backbone of α-T-Glcp-(1 → 6)-α-Glcp-(1 → 4)-α-Galp-(1 → 4)-α-Galp-(1 → 6)-α-Galp-(1 → 3)-α-Galp-(1 → . It inhibited activation of the TLR4/NF-κB signaling and reduced pro-inflammatory factors and NO in LPS-stimulated macrophage. Moreover, HDPS-1II increased the survival rate, inhibited inflammatory cells infiltration, and ameliorated the lung tissue damage in septic mice.

CONCLUSIONS

HDPS-1II exhibits anti-inflammatory effects in vitro and in vivo, which is the active polysaccharide components of the anti-inflammatory activity of Qi Cao.

Heparin-azithromycin microparticles show anti-inflammatory effects and inhibit SARS-CoV-2 and bacterial pathogens associated to lung infections

Pulmonary infections are a leading cause of morbidity and mortality worldwide, a situation exacerbated by the COVID-19. Azithromycin (AZM) is used orally to treat pulmonary infections due to its ability to accumulate in lung tissues and immune cells after oral administration. Sulfated polysaccharides, such as heparin, are known to inhibit SARS-CoV-2 entry. This study presents a novel approach focused on developing a dry powder inhaler of AZM-loaded microparticles composed of either heparin or its derivatives. The microparticle formulations exhibited potent antiviral activity against SARS-CoV-2 (IC50 ≤ 95 nM) while retaining superior antibacterial efficacy against Streptococcus pneumoniae and Pseudomonas aeruginosa compared to free AZM (MIC ≤15 μg/mL). Importantly, at bactericidal concentrations, no cytotoxic effects were observed on mammalian cells, including Calu-3 cells and red blood cells. The formulations demonstrated effective alveolar aerodynamic deposition (MMAD ranging from 1 μm to 3 μm) with a Fine Particle Fraction below 5 μm close to 50 %. Adopting a conservative estimate of 20 mL for the pulmonary epithelial lining fluid volume in healthy adults, efficacious local concentrations of sulfated polysaccharides and AZM would be delivered to the lung using this multifaceted strategy which holds promise for the treatment of bacterial pulmonary infections associated with COVID-19.

Efficacy and safety of anticoagulants on venous thromboembolism: a systematic review and network meta-analysis of randomized controlled trials

Background

Anticoagulants are the primary means for the treatment and prevention of venous thromboembolism (VTE), but their clinical standardized application still remains controversial. The present study intends to comprehensively compare the efficacy and safety of various anticoagulants in VTE.

Methods

Medline, Embase, and Cochrane Library from their inception up to August 2023 were searched to compare the efficacy and safety of various anticoagulants in VTE. We extracted data on study settings, baseline characteristics, interventions, and outcomes, applying the intention-to-treat principle. Two researchers assessed study bias using the Cochrane tool, resolving disagreements through discussion or third-party adjudication. Network meta-analyses were performed based on Bayesian generalized linear models, and a frequentist framework with multivariate random effects was used to fit the model.

Results

In terms of treatment, 58 trials with 119,417 patients proved eligible, while 125 trials with 225,414 patients were included in terms of prevention. All anticoagulants were found to reduce the recurrence or incidence of VTE compared with Placebo, of which high-level evidence indicated that direct thrombin inhibitors (TIs) and novel oral anticoagulants (NOACs) were the two most effective drugs. For treatment, low molecular weight heparin (LMWH), unfractionated heparin (UFH), and vitamin K antagonists (VKAs) significantly increased the risk of major bleeding in comparison to Placebo. For prevention, only UFH (OR 2.0, 95% CI 1.2-3.3) and NOACs (OR 1.8, 95% CI 1.2-2.6) showed significant increased risks in major bleeding. Additionally, after an exhaustive analysis of NOACs, analysis showed that apixaban (RR 0.5, 95%CI 0.17-1.46) had a superior performance in major bleeding compared to rivaroxaban (RR 3.87, 95%CI 1.48-10.09).

Conclusion

TIs and NOACs were superior in efficacy with minimal side effects, making them pivotal choices for both prevention and treatment of VTE. Clinical practitioners must carefully weigh drug characteristics, indications, and contraindications to optimize treatment outcomes.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=466775.

Targeting HMGB1 and Its Interaction with Receptors: Challenges and Future Directions

High mobility group box 1 (HMGB1) is a nonhistone chromatin protein predominantly located in the nucleus. However, under pathological conditions, HMGB1 can translocate from the nucleus to the cytoplasm and subsequently be released into the extracellular space through both active secretion and passive release mechanisms. The distinct cellular locations of HMGB1 facilitate its interaction with various endogenous and exogenous factors, allowing it to perform diverse functions across a range of diseases. This Perspective provides a comprehensive overview of the structure, release mechanisms, and multifaceted roles of HMGB1 in disease contexts. Furthermore, it introduces the development of both small molecule and macromolecule inhibitors targeting HMGB1 and its interaction with receptors. A detailed analysis of the predicted pockets is also presented, aiming to establish a foundation for the future design and development of HMGB1 inhibitors.

Expanding the recognition of monosaccharides and glycans: A comprehensive analytical approach using chemical-nose/tongue technology and a comparison to lectin microarrays

Chemical-nose/tongue technologies are emerging as promising analytical tools for glycan analysis. After briefly introducing the importance of glycans and their analytical methods, including the lectin microarray (LMA) as one of the gold standards, the fundamental principles underlying chemical noses/tongues are explained and various applications for monosaccharides and glycans are introduced. Then, the similarities and differences of these two approaches are discussed. While both technologies aim to comprehensively profile biospecimens based on 'interaction patterns' between multiple recognition probes and analytes, each has its own strengths. LMAs excel at specific, targeted analysis based on defined lectin-glycan interactions, whereas chemical nose/tongue offers greater flexibility and expandability in terms of system design, making it well-suited for discovering unknown glycan profiles and detecting broader differences in glycan mixtures. In the future, chemical-nose/tongue technologies may be applied to niche areas in glycan analysis and become powerful tools that complement LMA techniques.

Bioengineered heparin: Advances in production technology

Heparin, a highly sulfated glycosaminoglycan, is considered an indispensable anticoagulant with diverse therapeutic applications and has been a mainstay in medical practice for nearly a century. Its potential extends beyond anticoagulation, showing promise in treating inflammation, cancer, and infectious diseases such as COVID-19. However, its current sourcing from animal tissues poses challenges due to variable structures and adulterations, impacting treatment efficacy and safety. Recent advancements in metabolic engineering and synthetic biology offer alternatives through bioengineered heparin production, albeit with challenges such as controlling molecular weight and sulfonation patterns. This review offers comprehensive insight into recent advancements, encompassing: (i) the metabolic engineering strategies in prokaryotic systems for heparin production; (ii) strides made in the development of bioengineered heparin; and (iii) groundbreaking approaches driving production enhancements in eukaryotic systems. Additionally, it explores the potential of recombinant Chinese hamster ovary cells in heparin synthesis, discussing recent progress, challenges, and future prospects, thereby opening up new avenues in biomedical research.

Guidelines for management of actual or suspected inadvertent intra-arterial injection of sclerosants

BACKGROUND

Inadvertent intra-arterial injection of sclerosants is an uncommon adverse event of both ultrasound-guided and direct vision sclerotherapy. This complication can result in significant tissue or limb loss and significant long-term morbidity.

OBJECTIVES

To provide recommendations for diagnosis and immediate management of an unintentional intra-arterial injection of sclerosing agents.

METHODS

An international and multidisciplinary expert panel representing the endorsing societies and relevant specialities reviewed the published biomedical, scientific and legal literature and developed the consensus-based recommendations.

RESULTS

Actual and suspected cases of an intra-arterial sclerosant injection should be immediately transferred to a facility with a vascular/interventional unit. Digital Subtraction Angiography (DSA) is the key investigation to confirm the diagnosis and help select the appropriate intra-arterial therapy for tissue ischaemia. Emergency endovascular intervention will be required to manage the risk of major limb ischaemia. This includes intra-arterial administration of vasodilators to reduce vasospasm, and anticoagulants and thrombolytic agents to mitigate thrombosis. Mechanical thrombectomy, other endovascular interventions and even open surgery may be required. Lumbar sympathetic block may be considered but has a high risk of bleeding. Systemic anti-inflammatory agents, anticoagulants, and platelet inhibitors and modifiers would complement the intra-arterial endovascular procedures. For risk of minor ischaemia, systemic oral anti-inflammatory agents, anticoagulants, vasodilators and antiplatelet treatments are recommended.

CONCLUSION

Inadvertent intra-arterial injection is an adverse event of both ultrasound-guided and direct vision sclerotherapy. Medical practitioners performing sclerotherapy must ensure completion of a course of formal training (specialty or subspecialty training, or equivalent recognition) in the management of venous and lymphatic disorders (phlebology), and be personally proficient in the use of duplex ultrasound in vascular (both arterial and venous) applications, to diagnose and provide image guidance to venous procedure. Expertise in diagnosis and immediate management of an intra-arterial injection is essential for all practitioners performing sclerotherapy.

The accomplices: Heparan sulfates and N-glycans foster SARS-CoV-2 spike:ACE2 receptor binding and virus priming

Although it is well established that the SARS-CoV-2 spike glycoprotein binds to the host cell ACE2 receptor to initiate infection, far less is known about the tissue tropism and host cell susceptibility to the virus. Differential expression across different cell types of heparan sulfate (HS) proteoglycans, with variably sulfated glycosaminoglycans (GAGs), and their synergistic interactions with host and viral N-glycans may contribute to tissue tropism and host cell susceptibility. Nevertheless, their contribution remains unclear since HS and N-glycans evade experimental characterization. We, therefore, carried out microsecond-long all-atom molecular dynamics simulations, followed by random acceleration molecular dynamics simulations, of the fully glycosylated spike:ACE2 complex with and without highly sulfated GAG chains bound. By considering the model GAGs as surrogates for the highly sulfated HS expressed in lung cells, we identified key cell entry mechanisms of spike SARS-CoV-2. We find that HS promotes structural and energetic stabilization of the active conformation of the spike receptor-binding domain (RBD) and reorientation of ACE2 toward the N-terminal domain in the same spike subunit as the RBD. Spike and ACE2 N-glycans exert synergistic effects, promoting better packing, strengthening the protein:protein interaction, and prolonging the residence time of the complex. ACE2 and HS binding trigger rearrangement of the S2' functional protease cleavage site through allosteric interdomain communication. These results thus show that HS has a multifaceted role in facilitating SARS-CoV-2 infection, and they provide a mechanistic basis for the development of GAG derivatives with anti-SARS-CoV-2 potential.

Multifaceted Heparin: Diverse Applications beyond Anticoagulant Therapy

Heparin, a naturally occurring polysaccharide, has fascinated researchers and clinicians for nearly a century due to its versatile biological properties and has been used for various therapeutic purposes. Discovered in the early 20th century, heparin has been a key therapeutic anticoagulant ever since, and its use is now implemented as a life-saving pharmacological intervention in the management of thrombotic disorders and beyond. In addition to its known anticoagulant properties, heparin has been found to exhibit anti-inflammatory, antiviral, and anti-tumorigenic activities, which may lead to its widespread use in the future as an essential drug against infectious diseases such as COVID-19 and in various medical treatments. Furthermore, recent advancements in nanotechnology, including nano-drug delivery systems and nanomaterials, have significantly enhanced the intrinsic biofunctionalities of heparin. These breakthroughs have paved the way for innovative applications in medicine and therapy, expanding the potential of heparin research. Therefore, this review aims to provide a creation profile of heparin, space for its utilities in therapeutic complications, and future characteristics such as bioengineering and nanotechnology. It also discusses the challenges and opportunities in realizing the full potential of heparin to improve patient outcomes and elevate therapeutic interventions.

Discordance between aPTT and anti-Xa in monitoring heparin anticoagulation in mechanical circulatory support

AIMS

It is unclear whether activated partial thromboplastin time (aPTT) or anti-Xa is more accurate for monitoring heparin anticoagulation in mechanical circulatory support (MCS) patients. This study investigates the relationship between aPTT and anti-Xa in MCS patients and identifies predictors of discordance.

METHODS AND RESULTS

aPTT and anti-Xa were simultaneously measured in a prospective cohort of MCS patients receiving unfractionated heparin at a tertiary academic medical centre. Therapeutic aPTT and anti-Xa levels were 60-100 s and 0.3-0.7 IU/mL, respectively, and concordance was defined as both levels being subtherapeutic, therapeutic, or supratherapeutic. To identify predictors of discordance, both a machine learning random forest model and a multivariate regression model were applied to patient demographics, device type, and 14 laboratory variables; 23 001 pairs of simultaneously measured aPTT/anti-Xa were collected from 699 MCS patients. aPTT and anti-Xa were concordant in 35.5% of paired observations and discordant in 64.5% (aPTT > antiXa 61.5%; aPTT < antiXa 3.0%). Discordance with a high aPTT relative to anti-Xa (aPTT > antiXa) was associated with high INR, eGFR, and total bilirubin, as well as low platelets, haemoglobin, pre-albumin, white blood cell count, and haptoglobin. Total artificial heart and durable ventricular assist devices were more likely to be associated with aPTT > anti-Xa than temporary MCS devices.

CONCLUSIONS

aPTT and anti-Xa were frequently discordant in MCS patients receiving heparin anticoagulation. Clinical conditions common in MCS patients such as concurrent warfarin use, malnutrition, haemolysis, and thrombocytopenia, as well as durable type of MCS devices were associated with a high aPTT relative to anti-Xa.

Interleukin-4-Loaded Heparin Hydrogel Regulates Macrophage Polarization to Promote Osteogenic Differentiation

In bone tissue engineering, biological scaffolds are designed with structural and functional properties that closely resemble the extracellular environment, aiming to establish a microenvironment conducive to osteogenesis. Macrophages hold significant potential for promoting osteogenesis and modulating the biological behavior of tumor cells. Multiple coculture experiments of macrophages and osteoblasts have demonstrated that macrophage polarization significantly impacts osteogenesis. Therefore, exploring bone biomaterials that can modulate macrophage polarization holds great clinical significance. In this study, heparin was modified with maleimide and was used as a raw material to form a hydrogel with 4-am-PEG-SH. The compound was used to polarize macrophages and promote osteogenesis after combining with interleukin 4 (IL-4) by taking advantage of the electronegativity of heparin. The results revealed overexpressed M2 macrophage-related phenotypic genes and cocultivation with MC3T3-E1 cells demonstrated the osteogenesis-promoting effect of the loaded IL-4 heparin hydrogel. Previous research reported that hydrogel loaded with IL-4 can be used as a biomaterial for osteogenesis promotion. Heparin materials used in this paper are derived from clinically anticoagulant drugs and feature a simple operation. The synthesized hydrogel effectively binds cytokines, regulates macrophages to induce osteogenesis and has many potential clinical applications.

Quality control, safety assessment and preparation approaches of low molecular weight heparin

Low Molecular Weight Heparins (LMWHs) are well-established for use in the prevention and treatment of thrombotic diseases, and as a substitute for unfractionated heparin (UFH) due to their predictable pharmacokinetics and subcutaneous bioavailability. LMWHs are produced by various depolymerization methods from UFH, resulting in heterogeneous compounds with similar biochemical and pharmacological properties. However, the delicate supply chain of UFH and potential contamination from animal sources require new manufacturing approaches for LMWHs. Various LMWH preparation methods are emerging, such as chemical synthesis, enzymatic or chemical depolymerization and chemoenzymatic synthesis. To establish the sameness of active ingredients in both innovator and generic LMWH products, the Food and Drug Administration has implemented a stringent scientific method of equivalence based on physicochemical properties, heparin source material and depolymerization techniques, disaccharide composition and oligosaccharide mapping, biological and biochemical properties, and in vivo pharmacodynamic profiles. In this review, we discuss currently available LMWHs, potential manufacturing methods, and recent progress for manufacturing quality control of these LMWHs.

A disproportionality analysis of low molecular weight heparin in the overall population and in pregnancy women using the FDA adverse event reporting system (FAERS) database

Background

Low molecular weight heparin (LMWH) is extensively utilized as an anticoagulant for the prevention and management of various thrombotic conditions. However, despite the widespread use of LMWH in clinical indications, its adverse events (AEs) have not received substantial attention, and there is a lack of systematic and comprehensive AE studies. This study aims to evaluate AE signals associated with LMWH in the overall population and in pregnancy women from the FDA Adverse Event Reporting System database.

Methods

We used the Standardized MedDRA Query to identify pregnancy-related AE reports. Disproportionality analyses were employed to identify LMWH-related AE by calculating the reporting odds ratios (ROR), proportional reporting ratios (PRR), bayesian confidence propagation neural network (BCPNN), and the empirical Bayesian geometric mean (EBGM).

Results

For the overall population, the significantly reported adverse signals in SOCs were pregnancy, puerperium, and perinatal conditions, vascular disorders, blood and lymphatic system disorders, and product issues. The five strongest AEs signal of LMWH-related were anti factor X antibody positive (n = 6, ROR 506.70, PRR 506.65, IC 8.31, EBGM 317.03), heparin-induced thrombocytopenia test positive (n = 19, ROR 263.10, PRR 263.02, IC 7.65, EBGM 200.79), anti factor X activity increased (n = 10, ROR 255.93, PRR 255.89, IC 7.62, EBGM 196.61), heparin-induced thrombocytopenia test (n = 14, ROR 231.85, PRR 231.80, IC 7.51, EBGM 182.09), and spontaneous heparin-induced thrombocytopenia syndrome (n = 3, ROR 230.31, PRR 230.30, IC 7.50, EBGM 181.16). For pregnancy women, the five strongest AEs signals of LMWH-related included sternal fracture (n = 3, ROR 243.44, PRR 243.35, IC 6.61, EBGM 97.94), syringe issue (n = 12, ROR 97.49, PRR 97.34, IC 5.94, EBGM 61.21), bleeding time prolonged (n = 3, ROR 97.38, PRR 97.34, IC 5.94, EBGM 61.21), spinal compression fracture (n = 10, ROR 90.24, PRR 90.13, IC 5.87, EBGM 58.30), and injection site haematoma (n = 19, ROR 79.23, PRR 79.04, IC 5.74, EBGM 53.47). Additionally, unexpected AEs associated with LMWH in pregnancy women were observed, including premature baby death, placental necrosis, abortion, antiphospholipid syndrome, systolic dysfunction, compartment syndrome, body height decreased, rubella antibody positive, and ultrasound doppler abnormal.

Conclusion

This study identified unexpected AE signals of LMWH-relate in pregnancy women. Our study could provide valuable evidence for the clinical practice of LMWH, especially for identifying AEs and ensuring safe usage in pregnancy women.

Nano-anticoagulant based on carrier-free low molecular weight heparin and octadecylamine with an albumin shuttling effect

Low-molecular-weight heparin (LMWH), derived from unfractionated heparin (UFH), has enhanced anticoagulant efficacy, long duration of action, and extended half-life. Patients receiving LMWH for preventive therapies would strongly benefit from its long-term effects, however, achieving this is challenging. Here, we design and evaluate a nanoengineered LMWH and octadecylamine conjugate (LMHO) that can act for a long time while maintaining close to 97 ± 3% of LMWH activity via end-specific conjugation of the reducing end of LMWH. LMHO can self-assemble into nanoparticles with an average size of 105 ± 1.7 nm in water without any nanocarrier and can be combined with serum albumin, resulting in a lipid-based albumin shuttling effect. Such molecules can circulate in the bloodstream for 4-5 days. We corroborate the self-assembly capability of LMHO and its interaction with albumin through molecular dynamics (MD) simulations and transmission electron microscopy (TEM) analysis. This innovative approach to carrier-free polysaccharide delivery, enhanced by nanoengineered albumin shuttling, represents a promising platform to address limitations in conventional therapies.

Relation between antithrombin-III activity and activated clotting time for cardiopulmonary bypass

Heparin resistance (HR) is observed before cardiopulmonary bypass (CPB), despite with normal antithrombin III (AT-III) levels. The relationships between preoperative AT-III activity and activated clotting time (ACT) after the first heparin dose should be clarified. We retrospectively analyzed the data of 818 patients who underwent CPB surgery, with the initial heparin of 300, 400, and 500 IU/kg, between 2017 and 2021. We defined HR as the failure to achieve ACT after the initial heparin dose (Post ACT) of > 480 s.There were no significant correlations between the AT-III activity and Post ACT in all patients, including 143 patients with AT-III activity < 80% and 675 patients with AT-III activity of ≥ 80%. Also, there were no significant correlations between the AT-III activity and Post ACT in 74 patients who received heparin of 300 IU/kg, in 186 patients with 400 IU/kg, and in 339 patients with 500 IU/kg. After identifying smoking, HR, activated partial thromboplastin time, fibrinogen degradation products (FDP), and ACT as influencing factors, multiple comparisons using the Steel-Dwass test showed significant difference in FDP and HR among the patients who received heparin of 300 IU/kg, 400 IU/kg, and 500 IU/kg. There is no association between preoperative AT-III activity and ACT after the first heparin administration for CPB, even in different dose of heparin. Rather, the higher the initial UFH dose is, the higher ACT may be, regardless of the AT-III activity.

Management of Therapeutic-intensity Unfractionated Heparin: A Narrative Review on Critical Points

Nowadays, unfractionated heparin (UFH) use is limited to selected patient groups at high risk of both bleeding and thrombosis (patients in cardiac surgery, in intensive care unit, and patients with severe renal impairment), rendering its management extremely challenging, with many unresolved questions despite decades of use. In this narrative review, we revisit the fundamental concepts of therapeutic anticoagulation with UFH and address five key points, summarizing controversies underlying the use of UFH and discussing the few recent advances in the field: (1) laboratory tests for UFH monitoring have significant limitations; (2) therapeutic ranges are not well grounded; (3) the actual influence of antithrombin levels on UFH's anticoagulant activity is not well established; (4) the concept of UFH resistance lacks supporting data; (5) scarce data are available on UFH use beyond acute venous thromboembolism. We therefore identified key issues to be appropriately addressed in future clinical research: (1) while anti-Xa assays are often considered as the preferred option, we call for a vigorous action to improve understanding of the differences between types of anti-Xa assays and to solve the issue of the usefulness of added dextran; (2) therapeutic ranges for UFH, which were defined decades ago using reagents no longer available, have not been properly validated and need to be confirmed or reestablished; (3) UFH dose adjustment nomograms require full validation.

Generalized Multifunctional Coating Strategies Based on Polyphenol-Amine-Inspired Chemistry and Layer-by-Layer Deposition for Blood Contact Catheters

Blood-contacting catheters play a pivotal role in contemporary medical treatments, particularly in the management of cardiovascular diseases. However, these catheters exhibit inappropriate wettability and lack antimicrobial characteristics, which often lead to catheter-related infections and thrombosis. Therefore, there is an urgent need for blood contact catheters with antimicrobial and anticoagulant properties. In this study, we employed tannic acid (TA) and 3-aminopropyltriethoxysilane (APTES) to create a stable hydrophilic coating under mild conditions. Heparin (Hep) and poly(lysine) (PL) were then modified on the TA-APTES coating surface using the layer-by-layer (LBL) technique to create a superhydrophilic TA/APTES/(LBL)4 coating on silicone rubber (SR) catheters. Leveraging the superhydrophilic nature of this coating, it can be effectively applied to blood-contacting catheters to impart antibacterial, antiprotein adsorption, and anticoagulant properties. Due to Hep's anticoagulant attributes, the activated partial thromboplastin time and thrombin time tests conducted on SR/TA-APTES/(LBL)4 catheters revealed remarkable extensions of 276 and 103%, respectively, when compared to uncoated commercial SR catheters. Furthermore, the synergistic interaction between PL and TA serves to enhance the resistance of SR/TA-APTES/(LBL)4 catheters against bacterial adherence, reducing it by up to 99.9% compared to uncoated commercial SR catheters. Remarkably, the SR/TA-APTES/(LBL)4 catheter exhibits good biocompatibility with human umbilical vein endothelial cells in culture, positioning it as a promising solution to address the current challenges associated with blood-contact catheters.

Advancements in heparosan production through metabolic engineering and improved fermentation

Heparin is one of the most widely used natural drugs, and has been the preferred anticoagulant and antithrombotic agent in the clinical setting for nearly a century. Heparin also shows increasing therapeutic potential for treating inflammation, cancer, and microbial and viral diseases, including COVID-19. With advancements in synthetic biology, heparin production through microbial engineering of heparosan offers a cost-effective and scalable alternative to traditional extraction from animal tissues. Heparosan serves as the starting carbon backbone for the chemoenzymatic synthesis of bioengineered heparin, possessing a chain length that is critically important for the production of heparin-based therapeutics with specific molecular weight (MW) distributions. Recent advancements in metabolic engineering of microbial cell factories have resulted in high-yield heparosan production. This review systematically analyzes the key modules involved in microbial heparosan biosynthesis and the latest metabolic engineering strategies for enhancing production, regulating MW, and optimizing the fermentation scale-up of heparosan. It also discusses future studies, remaining challenges, and prospects in the field.

Biomedical potency and mechanisms of marine polysaccharides and oligosaccharides: A review

Derived from bountiful marine organisms (predominantly algae, fauna, and microorganisms), marine polysaccharides and marine oligosaccharides are intricate macromolecules that play a significant role in the growth and development of marine life. Recently, considerable attention has been paid to marine polysaccharides and marine oligosaccharides as auspicious natural products due to their promising biological attributes. Herein, we provide an overview of recent advances in the miscellaneous biological activities of marine polysaccharides and marine oligosaccharides that encompasses their anti-cancer, anti-inflammatory, antibacterial, antiviral, antioxidant, anti-diabetes mellitus, and anticoagulant properties. Furthermore, we furnish a concise summary of the underlying mechanisms governing the behavior of these biological macromolecules. We hope that this review inspires research on marine polysaccharides and marine oligosaccharides in medicinal applications while offering fresh perspectives on their broader facets.

Glycosaminoglycans' Ability to Promote Wound Healing: From Native Living Macromolecules to Artificial Biomaterials

Glycosaminoglycans (GAGs) are important for the occurrence of signaling molecules and maintenance of microenvironment within the extracellular matrix (ECM) in living tissues. GAGs and GAG-based biomaterial approaches have been widely explored to promote in situ tissue regeneration and repair by regulating the wound microenvironment, accelerating re-epithelialization, and controlling ECM remodeling. However, most approaches remain unacceptable for clinical applications. To improve insights into material design and clinical translational applications, this review highlights the innate roles and bioactive mechanisms of native GAGs during in situ wound healing and presents common GAG-based biomaterials and the adaptability of application scenarios in facilitating wound healing. Furthermore, challenges before the widespread commercialization of GAG-based biomaterials are shared, to ensure that future designed and constructed GAG-based artificial biomaterials are more likely to recapitulate the unique and tissue-specific profile of native GAG expression in human tissues. This review provides a more explicit and clear selection guide for researchers designing biomimetic materials, which will resemble or exceed their natural counterparts in certain functions, thereby suiting for specific environments or therapeutic goals.

Control of tissue homeostasis by the extracellular matrix: Synthetic heparan sulfate as a promising therapeutic for periodontal health and bone regeneration

Proteoglycans are core proteins associated with carbohydrate/sugar moieties that are highly variable in disaccharide composition, which dictates their function. These carbohydrates are named glycosaminoglycans, and they can be attached to proteoglycans or found free in tissues or on cell surfaces. Glycosaminoglycans such as hyaluronan, chondroitin sulfate, dermatan sulfate, keratan sulfate, and heparin/heparan sulfate have multiple functions including involvement in inflammation, immunity and connective tissue structure, and integrity. Heparan sulfate is a highly sulfated polysaccharide that is abundant in the periodontium including alveolar bone. Recent evidence supports the contention that heparan sulfate is an important player in modulating interactions between damage associated molecular patterns and inflammatory receptors expressed by various cell types. The structure of heparan sulfate is reported to dictate its function, thus, the utilization of a homogenous and structurally defined heparan sulfate polysaccharide for modulation of cell function offers therapeutic potential. Recently, a chemoenzymatic approach was developed to allow production of many structurally defined heparan sulfate carbohydrates. These oligosaccharides have been studied in various pathological inflammatory conditions to better understand their function and their potential application in promoting tissue homeostasis. We have observed that specific size and sulfation patterns can modulate inflammation and promote tissue maintenance including an anabolic effect in alveolar bone. Thus, new evidence provides a strong impetus to explore heparan sulfate as a potential novel therapeutic agent to treat periodontitis, support alveolar bone maintenance, and promote bone formation.

A tick saliva serpin, IxsS17 inhibits host innate immune system proteases and enhances host colonization by Lyme disease agent

Lyme disease (LD) caused by Borrelia burgdorferi is among the most important human vector borne diseases for which there is no effective prevention method. Identification of tick saliva transmission factors of the LD agent is needed before the highly advocated tick antigen-based vaccine could be developed. We previously reported the highly conserved Ixodes scapularis (Ixs) tick saliva serpin (S) 17 (IxsS17) was highly secreted by B. burgdorferi infected nymphs. Here, we show that IxsS17 promote tick feeding and enhances B. burgdorferi colonization of the host. We show that IxsS17 is not part of a redundant system, and its functional domain reactive center loop (RCL) is 100% conserved in all tick species. Yeast expressed recombinant (r) IxsS17 inhibits effector proteases of inflammation, blood clotting, and complement innate immune systems. Interestingly, differential precipitation analysis revealed novel functional insights that IxsS17 interacts with both effector proteases and regulatory protease inhibitors. For instance, rIxsS17 interacted with blood clotting proteases, fXII, fX, fXII, plasmin, and plasma kallikrein alongside blood clotting regulatory serpins (antithrombin III and heparin cofactor II). Similarly, rIxsS17 interacted with both complement system serine proteases, C1s, C2, and factor I and the regulatory serpin, plasma protease C1 inhibitor. Consistently, we validated that rIxsS17 dose dependently blocked deposition of the complement membrane attack complex via the lectin complement pathway and protected complement sensitive B. burgdorferi from complement-mediated killing. Likewise, co-inoculating C3H/HeN mice with rIxsS17 and B. burgdorferi significantly enhanced colonization of mouse heart and skin organs in a reverse dose dependent manner. Taken together, our data suggests an important role for IxsS17 in tick feeding and B. burgdorferi colonization of the host.

Update on the Pharmacological Actions of Enoxaparin in Nonsurgical Patients

Low-molecular-weight heparins are a class of drugs derived from the enzymatic depolymerization of unfractionated heparin that includes enoxaparin. Several studies have been performed on enoxaparin in recent years, in particular for the prevention and treatment of venous thromboembolism and for the treatment of acute coronary syndrome. Furthermore, the use of enoxaparin has been extended to other clinical situations that require antithrombotic pharmacological prevention, such as hemodialysis and recurrent abortion. In this review, we report the main clinical experiences of using enoxaparin in the prevention of VTE in nonsurgical patients.

Block Synthesis and Step-Growth Polymerization of C-6-Sulfonatomethyl-Containing Sulfated Malto-Oligosaccharides and Their Biological Profiling

Highly sulfated malto-oligomers, similar to heparin and heparan-sulfate, have good antiviral, antimetastatic, anti-inflammatory and cell growth inhibitory effects. Due to their broad biological activities and simple structure, sulfated malto-oligomer derivatives have a great therapeutic potential, therefore, the development of efficient synthesis methods for their production is of utmost importance. In this work, preparation of α-(1→4)-linked oligoglucosides containing a sulfonatomethyl moiety at position C-6 of each glucose unit was studied by different approaches. Malto-oligomeric sulfonic acid derivatives up to dodecasaccharides were prepared by polymerization using different protecting groups, and the composition of the product mixtures was analyzed by MALDI-MS methods and size-exclusion chromatography. Synthesis of lower oligomers was also accomplished by stepwise and block synthetic methods, and then the oligosaccharide products were persulfated. The antiviral, anti-inflammatory and cell growth inhibitory activity of the fully sulfated malto-oligosaccharide sulfonic acids were determined by in vitro tests. Four tested di- and trisaccharide sulfonic acids effectively inhibited the activation of the TNF-α-mediated inflammatory pathway without showing cytotoxicity.

Triple Action of Lignosulfonic Acid Sodium: Anti-protease, Antioxidant, and Anti-inflammatory Effects of a Polymeric Heparin Mimetic

BACKGROUND

Heparins are sulfated glycosaminoglycans that are used as anticoagulants to treat thrombosis. Heparins exhibit other potential therapeutic effects, such as anti-inflammatory, anti-viral, and anti-malarial effects. However, the strong anticoagulant activity of heparins poses a risk of life-threatening bleeding, limiting their therapeutic use for other diseases beyond thrombosis. To exploit the other effects of heparins and eliminate the bleeding risk, we explored an alternative polymer called lignosulfonic acid sodium (LSAS), which acts as a sulfonated heparin mimetic. LSAS targets factor XIa to exert an anticoagulant effect, and thus, unlike heparins, it is unlikely to cause bleeding.

METHODS

This study investigated the multiple effects of LSAS to identify potential leads for complex pathologies treatment. A series of chromogenic substrate hydrolysis assays were used to evaluate the inhibition of three inflammation-related proteases by LSAS. Its chemical antioxidant activity against the system of ABTS/hydrogen peroxide/metmyoglobin was also determined. Lastly, the effect of LSAS on TNFα-induced activation of the NF-κB pathway in HEK-293 cells was also tested to determine its cellular anti-inflammatory activity.

RESULTS

The results showed that LSAS effectively inhibited human neutrophil elastase, cathepsin G, and plasmin, with IC50 values ranging from 0.73 to 212.5 μg/mL. Additionally, LSAS demonstrated a significant chemical antioxidant effect, with an IC50 value of 44.1 μg/mL. Furthermore, at a concentration of approximately 530 μg/mL, LSAS inhibited the TNFα-induced activation of the NF-κB pathway in HEK-293 cells, indicating a substantial anti-inflammatory effect. An essential advantage of LSAS is its high water solubility and virtual non-toxicity, making it a safe and readily available polymer.

CONCLUSION

Based on these findings, LSAS is put forward as a polymeric heparin mimetic with multiple functions, serving as a potential platform for developing novel therapeutics to treat complex pathologies.

Identification and characterization of a novel heparinase PCHepII from marine bacterium Puteibacter caeruleilacunae

Heparin (HP) and heparan sulfate (HS) are multifunctional polysaccharides widely used in clinical therapy. Heparinases (Hepases) are enzymes that specifically catalyse HP and HS degradation, and they are valuable tools for studying the structure and function of these polysaccharides and for preparing low molecular weight heparins. In this study, by searching the NCBI database, a novel enzyme named PCHepII was discovered in the genome of the marine bacterium Puteibacter caeruleilacuae. Heterologously expressed PCHepII in Escherichia coli (BL21) has high expression levels and good solubility, active in sodium phosphate buffer (pH 7.0) at 20°C. PCHepII exhibits an enzyme activity of 254 mU/mg towards HP and shows weak degradation capacity for HS. More importantly, PCHepII prefers to catalyse the high-sulfated regions of HP and HS rather than the low-sulfated regions. Although PCHepII functions primarily as an endolytic Hepase, it mainly generates disaccharide products during the degradation of HP substrates over time. Investigations reveal that PCHepII exhibits a preference for catalysing the degradation of small substrates, especially HP tetrasaccharides. The catalytic sites of PCHepII include the residues His199, Tyr254, and His403, which play crucial roles in the catalytic process. The study and characterization of PCHepII can potentially benefit research and applications involving HP/HS, making it a promising enzyme.

Heparan Sulfate-Mimicking Glycopolymers Bind SARS-CoV-2 Spike Protein in a Length- and Sulfation Pattern-Dependent Manner

Heparan sulfate-mimicking glycopolymers, composed of glucosamine (GlcN)-glucuronic acid (GlcA) repeating units, bind to the receptor-binding subunit (S1) and spike glycoprotein (S) domains of the SARS-CoV-2 spike protein in a length- and sulfation pattern-dependent fashion. A glycopolymer composed of 12 repeating GlcNS6S-GlcA units exhibits a much higher affinity to the S1 protein (IC50 = 13 ± 1.1 nM) compared with the receptor-binding domain (RBD). This glycopolymer does not interfere in angiotensin-converting enzyme 2 binding of the RBD. Although this compound binds strongly to the S1/membrane-fusion subunit (S2) junction (KD = 29.7 ± 4.18 nM), it does not shield the S1/S2 site from cleavage by furin-a behavior contrary to natural heparin. This glycopolymer lacks iduronic acid, which accounts for 70% of heparin. Further, this compound, unlike natural heparin, is well defined in both sulfation pattern and length, which results in fewer off-target interactions with heparin-binding proteins. The results highlight the potential of using polymeric heparan sulfate (HS) mimetics for the therapeutic agent development.

Extraction, Isolation, Characterization, and Biological Activity of Sulfated Polysaccharides Present in Ascidian Viscera Microcosmus exasperatus

Ascidians are marine invertebrates that synthesize sulfated glycosaminoglycans (GAGs) within their viscera. Ascidian GAGs are considered analogues of mammalian GAGs and possess great potential as bioactive compounds, presenting antitumoral and anticoagulant activity. Due to its worldwide occurrence and, therefore, being a suitable organism for large-scale mariculture in many marine environments, our main objectives are to study Microcosmus exasperatus GAGs regarding composition, structure, and biological activity. We also aim to develop efficient protocols for sulfated polysaccharides extraction and purification for large-scale production and clinical applications. GAGs derived from M. exasperatus viscera were extracted by proteolytic digestion, purified by ion-exchange liquid chromatography, and characterized by agarose gel electrophoresis and enzymatic treatments. Anticoagulant activity was evaluated by APTT assays. Antitumoral activity was assessed in an in vitro model of tumor cell culture using MTT, clonogenic, and wound healing assays, respectively. Our results show that M. exasperatus presents three distinct polysaccharides; among them, two were identified: a dermatan sulfate and a fucosylated dermatan sulfate. Antitumoral activity was confirmed for the total polysaccharides (TP). While short-term incubation does not affect tumor cell viability at low concentrations, long-term TP incubation decreases LLC tumor cell growth/proliferation at different concentrations. In addition, TP decreased tumor cell migration at different concentrations. In conclusion, we state that M. exasperatus presents great potential as an alternative GAG source, producing compounds with antitumoral properties at low concentrations that do not possess anticoagulant activity and do not enhance other aspects of malignancy, such as tumor cell migration. Our perspectives are to apply these molecules in future preclinical studies for cancer treatment as antitumoral agents to be combined with current treatments to potentiate therapeutic efficacy.

Venous Thromboembolism Prophylaxis in Major Orthopedic Surgeries and Factor XIa Inhibitors

Venous thromboembolism (VTE), comprising pulmonary embolism (PE) and deep vein thrombosis (DVT), poses a significant risk during and after hospitalization, particularly for surgical patients. Among various patient groups, those undergoing major orthopedic surgeries are considered to have a higher susceptibility to PE and DVT. Major lower-extremity orthopedic procedures carry a higher risk of symptomatic VTE compared to most other surgeries, with an estimated incidence of ~4%. The greatest risk period occurs within the first 7-14 days following surgery. Major bleeding is also more prevalent in these surgeries compared to others, with rates estimated between 2% and 4%. For patients undergoing major lower-extremity orthopedic surgery who have a low bleeding risk, it is recommended to use pharmacological thromboprophylaxis with or without mechanical devices. The choice of the initial agent depends on the specific surgery and patient comorbidities. First-line options include low-molecular-weight heparins (LMWHs), direct oral anticoagulants, and aspirin. Second-line options consist of unfractionated heparin (UFH), fondaparinux, and warfarin. For most patients undergoing knee or hip arthroplasty, the initial agents recommended for the early perioperative period are LMWHs (enoxaparin or dalteparin) or direct oral anticoagulants (rivaroxaban or apixaban). In the case of hip fracture surgery, LMWH is recommended as the preferred agent for the entire duration of prophylaxis. However, emerging factor XI(a) inhibitors, as revealed by a recent meta-analysis, have shown a substantial decrease in the occurrence of VTE and bleeding events among patients undergoing major orthopedic surgery. This discovery poses a challenge to the existing paradigm of anticoagulant therapy in this specific patient population and indicates that factor XI(a) inhibitors hold great promise as a potential strategy to be taken into serious consideration.

Approaches to Assure Similarity between Pharmaceutical Heparins from Two Different Manufacturers

Pharmaceutical heparins from different manufacturers may present heterogeneities due to particular extraction and purification procedures or even variations in the raw material manipulation. Heparins obtained from different tissues also differ in their structure and activity. Nevertheless, there is an increased demand for more accurate assessments to ensure the similarities of pharmaceutical heparins. We propose an approach to accurately assess the similarity of these pharmaceutical preparations based on well-defined criteria, which are verified with a variety of refined analytical methods. We evaluate six commercial batches from two different manufacturers which were formulated with Brazilian or Chinese active pharmaceutical ingredients. Biochemical and spectroscopic methods and analysis based on digestion with heparinases were employed to evaluate the purity and structure of the heparins. Specific assays were employed to evaluate the biological activity. We observed minor but significant differences between the constitutive units of the heparins from these two manufacturers, such as the content of N-acetylated α-glucosamine. They also have minor differences in their molecular masses. These physicochemical differences have no impact on the anticoagulant activity but can indicate particularities on their manufacturing processes. The protocol we propose here for analyzing the similarity of unfractionated heparins is analogous to those successfully employed to compare low-molecular-weight heparins.