Antiaggregatory Activity Research Articles

Platelet antiaggregant activity of Hypericum perforatum extracts

BackgroundIn addition to its potential use as an antidepressant, different studies have shown that Hypericum perforatum (HP) can have antibacterial, antioxidant, and antiviral properties. Despite this potential, most of the therapeutic bioactivities attributed to HP need further scientific support. In a previous study we found an inhibitory effect of HP in platelet activation markers. So, in the present work we investigate the effect of HP in another aspect of platelet function, platelet aggregation. MethodsFirst, the effect of different concentrations of the total alcoholic extract of HP on platelet aggregation was studied in 9 healthy donors by aggregometry methods using collagen as agonist. After that, to obtain dose-effect curves, 3 experiments were carried out independently in a single individual using collagen, adenosine diphosphate and epinephrine as agonists. ResultsOur results reveal a marked inter-individual variability and a significant dose-dependent decrease of aggregation responses induced by collagen in the presence of HP extracts (mean of minimum inhibition: 8% at a dose of 0.068 mg es/ml and mean of maximum inhibition: 43% at a dose of 0.456 mg es/ml). With the results obtained it was possible to obtained a IC50 value of 0.34 mg es/ml. ConclusionsWe can conclude that HP has a dose-dependent inhibitory effect on platelet function (activation and aggregation responses), therefore, our results suggest that HP may be recognized as an herbal medicine with anti-platelet properties.

Synthesis and Evolution of Antioxidant, Anticoagulation, and Antiaggregation Activities of Levoglucosenone Adducts Containing Methyl-Substituted Phenyl Fragments

Synthesis and Evolution of Antioxidant, Anticoagulation, and Antiaggregation Activities of Levoglucosenone Adducts Containing Methyl-Substituted Phenyl Fragments

Localization and Aggregation of Honokiol in the Lipid Membrane.

Honokiol, a biphenyl lignan extracted from bark extracts belonging to Magnolia plant species, is a pleiotropic compound which exhibits a widespread range of antioxidant, antibacterial, antidiabetic, anti-inflammatory, antiaggregant, analgesic, antitumor, antiviral and neuroprotective activities. Honokiol, being highly hydrophobic, is soluble in common organic solvents but insoluble in water. Therefore, its biological effects could depend on its bioactive mechanism. Although honokiol has many impressive bioactive properties, its effects are unknown at the level of the biological membrane. Understanding honokiol's bioactive mechanism could unlock innovative perspectives for its therapeutic development or for therapeutic development of molecules similar to it. I have studied the behaviour of the honokiol molecule in the presence of a plasma-like membrane and established the detailed relation of honokiol with membrane components using all-atom molecular dynamics. The results obtained in this work sustain that honokiol has a tendency to insert inside the membrane; locates near and below the cholesterol oxygen atom, amid the hydrocarbon membrane palisade; increases slightly hydrocarbon fluidity; does not interact specifically with any membrane lipid; and, significantly, forms aggregates. Significantly, aggregation does not impede honokiol from going inside the membrane. Some of the biological characteristics of honokiol could be accredited to its aptitude to alter membrane biophysical properties, but the establishment of aggregate forms in solution might hamper its clinical use.

Tau Protein and Tauopathies: Exploring Tau Protein-Protein and Microtubule Interactions, Cross-Interactions and Therapeutic Strategies.

Tau, a microtubule-associated protein (MAP), is essential to maintaining neuronal stability and function in the healthy brain. However, aberrant modifications and pathological aggregations of Tau are implicated in various neurodegenerative disorders, collectively known as tauopathies. The most common Tauopathy is Alzheimer's Disease (AD) counting nowadays more than 60 million patients worldwide. This comprehensive review delves into the multifaceted realm of Tau protein, puzzling out its intricate involvement in both physiological and pathological roles. Emphasis is put on Tau Protein-Protein Interactions (PPIs), depicting its interaction with tubulin, microtubules and its cross-interaction with other proteins such as Aβ1-42, α-synuclein, and the chaperone machinery. In the realm of therapeutic strategies, an overview of diverse possibilities is presented with their relative clinical progresses. The focus is mostly addressed to Tau protein aggregation inhibitors including recent small molecules, short peptides and peptidomimetics with specific focus on compounds that showed a double anti aggregative activity on both Tau protein and Aβ amyloid peptide. This review amalgamates current knowledge on Tau protein and evolving therapeutic strategies, providing a comprehensive resource for researchers seeking to deepen their understanding of the Tau protein and for scientists involved in the development of new peptide-based anti-aggregative Tau compounds.

The mechanistic interaction, aggregation and neurotoxicity of α-synuclein after interaction with glycyrrhizic acid: Modulation of synucleinopathies

This article reveals the binding mechanism between glycyrrhizic acid (GA) and α-synuclein to may provide further information for the modulation of synucleinopathies using bioactive compounds. Therefore, the inhibitory activities of GA against α-synuclein aggregation and induced neurotoxicity were evaluated using different assays. Results showed that α-synuclein–GA binding was mediated by intermolecular hydrogen bonds leading to the formation of a slightly folded complex. Theoretical studies revealed that GA binds to the N-terminal domain of α-synuclein and triggers a compact structure around a major part of the N-terminal and the NAC regions along with fluctuations in the C-terminal domain, which are prerequisites for the inhibition of α-synuclein aggregation. Then, the cellular assays showed that GA as a potential small molecule can inhibit the oligomerization of α-synuclein and relevant neurotoxicity through modulation of neural viability, membrane leakage, and ROS formation in a concentration-dependent manner. As a result, the primary mechanism of GA's anti-aggregation and neuroprotective activities is the reorganized α-synuclein structure and fluctuating C-terminal domain, which promotes long-range transient intramolecular contacts between the N-terminal and the C-terminal domain.

Biotransformation of bitter gourd (Momordica charantia) by Lactobacillus plantarum and its bioactivities

Bitter gourd is renowned for its various bioactivities, including antioxidant, antiglycation, and antiplatelet aggregation. However, the bioactivity and bioavailability of plant extracts could be low. Biotransformation through Lactobacillus plantarum fermentation is capable of enhancing these beneficial properties. Therefore, the present work aimed to investigate the physical and pH profiles, total phytochemical contents, bioactive contents, and bioactivities of the juices of unfermented bitter gourd (UBG) and fermented bitter gourd at 48 (FBG-48) and 96 (FBG-96) h. Fermentation gradually altered the physical and pH profile of bitter gourd, while non-significant decrease was seen in the total flavonoid content (p > 0.05). The highest total phenolic content was observed in FBG-48, followed by UBG and FBG-96. UBG exhibited the highest total triterpenoid content, followed by FBG-48 and FBG-96. Interestingly, fermentation increased the antioxidant, antiglycation, and anti-aggregation activities of bitter gourd. FBG-48 demonstrated the highest antioxidant and antiglycation activities, with 10.77 and 8.68% higher activity, respectively, compared to UBG and FBG-96. Meanwhile, FBG-96 exhibited the highest antiglycation activity, with 60% increase. These could have been attributed to the biotransformation of tannic acid into syringic acid, and momordicoside Q into kuguacin P, along with the potential release of p-coumaric acid and caffeic acid from the cell walls. These findings demonstrated bitter gourd’s promising role in type-II diabetes complication treatment, particularly through its protein aggregation inhibition activity, and that fermentation could increase its bioactivities.

Modulating the aggregation of human prion protein PrP106-126 by an indole-based cyclometallated palladium complex.

The spontaneous aggregation of infectious or misfolded forms of prion protein is known to be responsible for neurotoxicity in brain cells, which ultimately leads to the progression of prion disorders. Bovine spongiform encephalopathy (BSE) in animals and Creutzfeldt-Jakob disease (CJD) in humans are glaring examples in this regard. Square-planar complexes with labile ligands and indole-based compounds are found to be efficiently inhibitory against protein aggregation. Herein, we report the synthesis of an indole-based cyclometallated palladium complex. The ligand and complex were characterized by various spectroscopic techniques such as UV-visible, NMR, IR, and HRMS. The molecular structure of the complex was confirmed by single-crystal X-ray crystallography. The interaction of the complex with PrP106-126 was studied using UV-visible spectroscopy, CD spectroscopy, MALDI-TOF MS, and molecular docking. The inhibition effects of the complex on the PrP106-126 aggregation, fibrillization and amyloid formation phenomena were analysed through the ThT assay, CD, TEM and AFM. The effect of the complex on the aggregation process of PrP106-126 was determined kinetically through the ThT assay. The complex presented high binding affinity with the peptide and influenced the peptide's conformation and aggregation in different modes of binding. Furthermore, the MTT assay on neuronal HT-22 cells showed considerable protective properties of the complex against PrP106-126-mediated cytotoxicity. These findings suggest that the compound influences peptide aggregation in different ways, and the anti-aggregation action is primarily associated with the metal's physicochemical properties and the reactivity rather than the ligand. As a result, we propose that this compound be investigated as a potential therapeutic molecule in metallopharmaceutical research to treat prion disease (PD).

Cilostazol niosomes-loaded transdermal gels: An in vitro and in vivo anti-aggregant and skin permeation activity investigations towards preparing an efficient nanoscale formulation

Cilostazol niosomes-loaded transdermal gels: An <i>in vitro</i> and <i>in vivo</i> anti-aggregant and skin permeation activity investigations towards preparing an efficient nanoscale formulation

Unraveling the Mechanism of Platelet Aggregation Suppression by Thioterpenoids: Molecular Docking and In Vivo Antiaggregant Activity.

Natural monoterpenes and their derivatives are widely considered the effective ingredients for the design and production of novel biologically active compounds. In this study, by using the molecular docking technique, we examined the effects of two series of "sulfide-sulfoxide-sulfone" thioterpenoids containing different (e.g., bornane and pinane) monoterpene skeletons on the platelet's aggregation. Our data revealed that all the synthesized compounds exhibit inhibitory activities on platelet aggregation. For example, compound 1 effectively inhibited platelet activation and demonstrated direct binding with CD61 integrin, a well-known platelet GPIIb-IIIa receptor on platelets. We further examined the antiaggregant activity of the most active compound, 1, in vivo and compared its activity with that of acetylsalicylic acid and an oral GPIIb-IIIa blocker, orbofiban. We found that compound 1 demonstrates antiaggregant activity in rats when administered per os and its activity was comparable with that of acetylsalicylic acid and orbofiban. Moreover, similarly, tirofiban, a well-known GPIIb-IIIa blocker, compound 1, effectively decreased the expression of P-selectin to the values similar to those of the intact platelets. Collectively, here, we show, for the first time, the potent antiaggregant activity of compound 1 both in vitro and in vivo due to its ability to bind with the GPIIb-IIIa receptor on platelets.

Human platelets and megakaryocytes express the BPIFB4 protein and their stimulation with the recombinant Longevity-associated variant LAV-BPIFB4 displays anti-aggregating activity

Abstract Platelets are not only the main players in primary haemostasis and cardiovascular disease, but recent advances attribute them a key role in immune defence mechanisms via the release of plasma mediators of potential clinical relevance. The bactericidal/permeability-increasing fold-containing family B, member 4 (BPIFB4) belongs to a family protein participating in the innate mechanism of host defence. It is a secreted protein and its plasma levels inversely correlated with COVID-19 and coronary artery disease (CAD) severity and the degree of carotid stenosis and intima media thickness in human patient cohorts. Interestingly, Long Living Individuals (LLIs) displayed high BPIFB4 circulating levels and an enrichment of the 4 SNPs missense haplotype at BPIFB4 locus, the Longevity-Associated Variant (LAV). LAV-BPIFB4 genotype correlate with higher BPIFB4 plasma levels and the transfer of LAV-BPIFB4 gene delayed major age-related diseases, mainly rescuing the immunesenescence and the endothelial and cardiac dysfunctions, yet the critical assessment of the BPIFB4 protein as a platelet release product is lacking. Herein we observed BPIFB4 release by calcium activated human platelets, a process that is amplified in LAV allele carriers donors. Furthermore, LAV gene transfer resulted in an enhanced protein enrichment in bone marrow megakaryocyte precursor cells and in a more efficient process of platelets formation in vitro. At functional level, LAV genotype was mimicked by the rhLAV-BPIFB4 platelet stimulation that induced endogenous BPIFB4 release similarly to calcium stimuli. In a small cohort of treatment-naive patients with type 2 diabetes, while ADP and Collagene agonist stimulation induced high aggregation, the co-treatment with the rhLAV-BPIFB4 significantly reduced the activation capacity of patients’ platelets. Accordingly, an administration of rhLAV-BPIFB4 24 hours before tromboembolism induction partly protected from mortality in a murine model of lethal pulmonary thromboembolism in vivo. As a result of reduced platelets’ activation, lower level of circulating leukocyte-platelets aggregates (LPA) was found in rhLAV-BPIFB4-treated mice compared to control. In summary, our data report for the first time that both, human platelets and megakaryocytes, can express BPIFB4 and unravel a novel rhLAV-BPIFB4 therapeutic action in platelet iperaggregation and thrombocytopenia.

Novel Substituted Azoloazines with Anticoagulant Activity

Hypercytokinemia, or cytokine storm, often complicates the treatment of viral and bacterial infections, including COVID-19, leading to the risk of thrombosis. However, the use of currently available direct anticoagulants for the treatment of COVID-19 patients is limited due to safety reasons. Therefore, the development of new anticoagulants remains an urgent task for organic and medicinal chemistry. At the same time, new drugs that combine anticoagulant properties with antiviral or antidiabetic activity could be helpfull in the treatment of COVID-19 patients, especially those suffering from such concomitant diseases as arterial hypertension or diabetes. We have synthesized a number of novel substituted azoloazines, some of which have previously been identified as compounds with pronounced antiviral, antibacterial, antidiabetic, antiaggregant, and anticoagulant activity. Two compounds from the family of 1,2,4-triazolo[1,5-a]pyrimidines have demonstrated anticoagulant activity at a level exceeding or at least comparable with that of dabigatran etexilate as the reference compound. 7,5-Di(2-thienyl)-4,5-dihydro-[1,2,4]triazolo[1,5-a]pyrimidine has shown the highest ability to prolong the thrombin time, surpassing this reference drug by 2.2 times. This compound has also exhibited anticoagulant activity associated with the inhibition of thrombin (factor IIa). Moreover, the anticoagulant effect of this substance becomes enhanced under the conditions of a systemic inflammatory reaction.

New Biotinylated GHK and Related Copper(II) Complex: Antioxidant and Antiglycant Properties In Vitro against Neurodegenerative Disorders.

Neurodegenerative diseases affect millions of people worldwide. The failure of the enzymatic degradation, the oxidative stress, the dyshomeostasis of metal ions, among many other biochemical events, might trigger the pathological route, but the onset of these pathologies is unknown. Multi-target and multifunctional molecules could address several biomolecular issues of the pathologies. The tripeptide GHK, a bioactive fragment of several proteins, and the related copper(II) complex have been largely used for many purposes, from cosmetic to therapeutic applications. GHK derivatives were synthesized to increase the peptide stability and improve the target delivery. Herein we report the synthesis of a new biotin-GHK conjugate (BioGHK) through orthogonal reactions. BioGHK is still capable of coordinating copper(II), as observed by spectroscopic and spectrometric measurements. The spectroscopic monitoring of the copper-induced ascorbate oxidation was used to measure the antioxidant activity Cu(II)-BioGHK complex, whereas antiglycant activity of the ligand towards harmful reactive species was investigated using MALDI-TOF. The affinity of BioGHK for streptavidin was evaluated using a spectrophotometric assay and compared to that of biotin. Finally, the antiaggregant activity towards amyloid-β was evaluated using a turn-on fluorescent dye. BioGHK could treat and/or prevent several adverse biochemical reactions that characterize neurodegenerative disorders, such as Alzheimer's disease.

Synthesis, Structure, and Properties of the Iron Nitrosyl Complex with 2-Ethyl-4-pyridinecarbothioamide

The synthesis and data on the physicochemical characteristics and biological activity of the newiron nitrosyl complex (Q+)2[Fe2(S2O3)2(NO)4]2– (I), where Q+ is protonated 2-ethyl-4-pyridinecarbothioamide(C8H11N2S), are presented. The structure and properties of the complex were studied by X-ray diffraction,elemental analysis, IR and Mössbauer spectroscopy, and amperometry. The complex showed antibacterialactivity and efficiently inhibited cyclic guanosine monophosphate phosphodiesterase (cGMP PDE),which may suggest its antihypertensive, anti-aggregation, and vasodilator activities.

Fluorogenic sensing of amorphous aggregates, amyloid fibers, and chaperone activity via a near‐infrared aggregation‐induced emission‐active probe

AbstractThe presence of protein aggregates in numerous human diseases underscores the significance of detecting these aggregates to comprehend disease mechanisms and develop novel therapeutic approaches for combating these disorders. Despite the development of various biosensors and fluorescent probes that selectively target amyloid fibers or amorphous aggregates, there is still a lack of tools capable of simultaneously detecting both types of aggregates. Herein, we demonstrate the quantitative discernment of amorphous aggregates by QM‐FN‐SO3, an aggregation‐induced emission (AIE) probe initially designed for detecting amyloid fibers. This probe easily penetrates the membranes of the widely‐used prokaryotic model organism Escherichia coli, enabling the visualization of both amorphous aggregates and amyloid fibers through near‐infrared fluorescence. Notably, the probe exhibits sensitivity in distinguishing the varying aggregation propensities of proteins, regardless of whether they form amorphous aggregates or amyloid fibers in vivo. These properties contribute to the successful application of the QM‐FN‐SO3 probe in the subsequent investigation of the antiaggregation activities of two outer membrane protein (OMP) chaperones, both in vitro and in their physiological environment. Overall, our work introduces a near‐infrared fluorescent chemical probe that can quantitatively detect amyloid fibers and amorphous aggregates with high sensitivity in vitro and in vivo. Furthermore, it demonstrates the applicability of the probe in chaperone biology and its potential as a high‐throughput screening tool for protein aggregation inhibitors and folding factors.

KLVFF Conjugated Curcumin Microemulsion-Based Hydrogel for Transnasal Route: Formulation Development, Optimization, Physicochemical Characterization, and Ex Vivo Evaluation.

Curcumin is a potent natural compound used to treat Alzheimer's disease (AD). However, the clinical usefulness of curcumin to treat AD is restricted by its low oral bioavailability and difficulty permeating the blood-brain barrier. To overcome such drawbacks, various alternative strategies have been explored, including the transnasal route. However, rapid mucociliary clearance in the nasal cavity is a major hindrance to drug delivery. Thus, designing a delivery system for curcumin to lengthen the contact period between the drug and nasal mucosa must be employed. This study describes the optimization of KLVFF conjugated curcumin microemulsion-base hydrogel (KCMEG) to formulate a prototype transnasal preparation using the response surface method to improve a mucoadhesive property. A central composite design was employed to optimize and evaluate two influencing factors: the concentration of carbopol 940 and the percentage of KLVFF conjugated curcumin microemulsion (KCME). The physicochemical properties, anti-cholinesterase activity, and anti-aggregation activities of KCME were investigated in this study. The studied factors, in terms of main and interaction effects, significantly (p < 0.05) influenced hardness and adhesiveness. The optimized KCMEG was evaluated for pH, spreadability, and mucoadhesive properties. Ex vivo nasal ciliotoxicity to optimize KCMEG was performed through the porcine nasal mucosa. KCME was transparent, with a mean globule size of 70.8 ± 3.4 nm and a pH of 5.80 ± 0.02. The optimized KCMEG containing 2% carbopol 940 showed higher in vitro mucoadhesive potential (9.67 ± 0.13 min) compared with microemulsion and was also found to be free from nasal ciliotoxicity during histopathologic evaluation of the porcine nasal mucosa. The result revealed that both the concentration of carbopol 940 and the percentage of KCME play a crucial role in mucoadhesive properties. In conclusion, incorporating a mucoadhesive agent in a microemulsion can increase the retention time of the formulation, leading to enhanced brain delivery of the drug. Findings from the investigation revealed that KCMEG has the potential to constitute a promising approach to treating AD via transnasal administration.

Antioxidant and antithrombotic activities of the Distichochlamys citrea leaves extract

Distichochlamys citrea (DC) is an endemic ginger species used in treating associated-heart diseases in traditional medicine in Vietnam. However, scientific evidence to support the local use of this plant was limited. The present study aimed to investigate the antioxidant and antithrombotic activities of D. citrea extracts for the first time. The antioxidant activity of DC extracts was assessed by scavenging DPPH radical and measuring their total phenolic content (TPC). The antithrombotic activity was evaluated by inhibiting platelet aggregation and prolonging blood coagulation. Volatile components elucidated by GC-MS were docked with typical platelet receptors, including COX-1 and P2Y12. Results showed that the methanol extract of D. citrea exhibited a stronger DPPH scavenging ability (IC50 = 0.33 ± 0.00 mg/mL) and a higher TPC (8.09 ± 0.21%) than other extracts (p &lt; 0.05). On the other hand, the hexane extract of D. citrea (DC-HX) had a remarkable inhibiting impact on ADP-, collagen- and ristocetin–induced platelet aggregation in a dose-dependent manner (Pearson’s correlation, r &gt; 0.90, p &lt; 0.05). In contrast, this extract did not lengthen the clotting time through any factors, such as PT (prothrombin time), and TT (thrombin time), except for APTT (activated partial thromboplastin time) at 4 mg/mL of the extract. GC-MS revealed that oxygenated hydrocarbons (54.45%) dominated the volatile profile of DC-HX, followed by sesquiterpens (37.18%) and diterpenes (6.66%). In the platelet aggregation process, several compounds in DC-HX were firmly bound to COX-1 and P2Y12, which might partly explain the significant antiaggregatory activity of this fraction. In conclusion, Distichochlamys citrea may be a potential source of active phytoconstituents for treating radicals- and cardiovascular-associated diseases.

The Therapeutic Potential of Novel Carnosine Formulations: Perspectives for Drug Development.

Carnosine (beta-alanyl-L-histidine) is an endogenous dipeptide synthesized via the activity of the ATP-dependent enzyme carnosine synthetase 1 and can be found at a very high concentration in tissues with a high metabolic rate, including muscles (up to 20 mM) and brain (up to 5 mM). Because of its well-demonstrated multimodal pharmacodynamic profile, which includes anti-aggregant, antioxidant, and anti-inflammatory activities, as well as its ability to modulate the energy metabolism status in immune cells, this dipeptide has been investigated in numerous experimental models of diseases, including Alzheimer's disease, and at a clinical level. The main limit for the therapeutic use of carnosine is related to its rapid hydrolysis exerted by carnosinases, especially at the plasma level, reason why the development of new strategies, including the chemical modification of carnosine or its vehiculation into innovative drug delivery systems (DDS), aiming at increasing its bioavailability and/or at facilitating the site-specific transport to different tissues, is of utmost importance. In the present review, after a description of carnosine structure, biological activities, administration routes, and metabolism, we focused on different DDS, including vesicular systems and metallic nanoparticles, as well as on possible chemical derivatization strategies related to carnosine. In particular, a basic description of the DDS employed or the derivatization/conjugation applied to obtain carnosine formulations, followed by the possible mechanism of action, is given. To the best of our knowledge, this is the first review that includes all the new formulations of carnosine (DDS and derivatives), allowing a decrease or complete prevention of the hydrolysis of this dipeptide exerted by carnosinases, the simultaneous blood-brain barrier crossing, the maintenance or enhancement of carnosine biological activity, and the site-specific transport to different tissues, which then offers perspectives for the development of new drugs.

Ex vivo STUDY OF THE ACTION OF INTEGRIN RECEPTORS ANTAGONIST FROM ECHIS MULTISQUAMATIS SNAKE VENOM ON PLATELETS OF PREGNANT WOMEN WITH COMPICATIONS DURING GESTATION

Aim. In our work, we studied platelet aggregation in blood plasma of pregnant women and estimated the possibility of ex vivo normalization of aggregation rate using a polypeptide from the Echis multisquamatus snake venom. Previous reports demonstrated that it directly interacts with glycoprotein IIb/IIIa receptors on the surface of platelets, preventing their adhesion, thereby affecting the degree of aggregation. Methods. chromatography followed by size-exclusion chromatography on Superdex 75 using the FPLC system (ӒKTA, GE Healthcare, USA). Analysis of molecular weight of protein components was performed using SDS-PAGE. The concentration of protein was measured using spectrophotometer Optizen POP (Korea) at 280 nm. The ability of obtained protein to inhibit platelet aggregation was measured directly by aggregometry. Blood samples of women with placental disfunction during pregnancy (n = 28) were kindly provided by “Perinatal Center of Kyiv”. This study was approved by the Ethics Commission of the Shupyk National Medical Academy of Postgraduate Education and the Ethics Commission of the Kyiv Perinatal Center (# 3 from 05/05/2020). Aggregation of platelet-rich plasma (PRP) induced by ADP was investigated using aggregometry on the AP 2110 (Solar, Belarus). We compared the rate of platelet aggregation in the presence vs absence of platelet aggregation inhibitor. Results. Two-step chromatography protocol allowed us to obtain the polypeptide from the venom of Echis multisquamatus that possessed the anti-aggregatory action. SDS-PAGE analysis confirmed the homogeneity of obtained polypeptide with apparent molecular weight 14 kDa that corresponds to the platelet aggregation inhibitor reported earlier. Initial studies of ADPinduced platelet aggregation allowed selecting active concentration for the effective inhibitory action as 0.02 mg/ml. Conclusions. Platelet aggregation inhibitor from Echis multisquamatis snake venom of can be assumed as the effective agent that reduce the rate of platelet aggregation. We demonstrated it efficacy in platelet rich plasma of pregnant women that had placenta dysfunction. The use of direct antagonist of platelet integrin receptors was assumed as the prospective approach for suppressing of platelet reactivity in particular during complicated pregnancy.

Hyperhomocysteinemia and pregnancy: about a case and literature review

Homocysteine ​​(Hct) is a substance produced in the metabolism of methionine that can be found in our daily diet. Mutation of the methylenetetrahydrofolate reductase (MTHFR) gene, especially in women with low folate intake. Hyperhomocysteinemia (HHct) can be caused by several factors, such as lack of folic acid, vitamin B6 and B12 deficiency, hypothyroidism, medications, genetic abnormalities, aging and kidney dysfunction. Increased homocysteine ​​in peripheral blood can lead to vascular disease, coronary artery dysfunction, atherosclerotic changes, and embolic disease. Thus, upstream of the trophoblastic plugs, any increase in the thrombogenic power of pregnant women will lead to the formation of a clot and the termination of pregnancy. Recent studies have reported that hyperhomocysteinemia is associated with numerous pregnancy complications, including abortion disease, preeclampsia, preterm birth, hematoma placentae, fetal growth restriction, and gestational diabetes. To avoid thrombosis, the treatment will therefore be based on anticoagulants, sometimes combined with low-dose aspirin because of the anti-aggregating action of the latter. In this article, we report the case of a patient with a history of abortive disease on hyperhomocysteinemia who carried a pregnancy to term, while recalling the metabolism of homocysteine, its impact on pregnancy, and the interest of supplementation folic acid to prevent complications due to hyperhomocysteinemia.

Effects of Walnut Bark Extract on the Human Platelet Aggregation, Adhesion, and Plasmatic Coagulation In Vitro.

Thrombosis is the formation of a clot within a blood vessel. Antithrombotic drugs are used for treating thrombosis, which can be the cause of hemorrhage. Currently, there is a need to discover novel antithrombotic drugs. Walnut is widely used to treat a wide range of health complaints. In this study, walnut bark extract was tested in hemostasis parameters: platelets adhesion, aggregation, and plasmatic coagulation in human blood. The crude aqueous extract of walnut bark was prepared by infusion and tested in vitro on hemostasis. Through blood collection from healthy volunteer donors, we studied different parameters of the primary hemostasis: platelet adhesion on the collagen-coated surface under flow, ADP, collagen, thrombin, and arachidonic acid-induced platelet aggregation, and of the secondary hemostasis by measuring prothrombin time (PT) and activated partial thromboplastin (APTT) parameters. All experiments are realized in the absence and presence of the extract and repeated at least twice. The obtained data showed that the extract (1 and 2 mg/mL) significantly (p < 0.001) reduced the activated platelet adhesion on the collagen-coated surface. In the same way, the effect of the extract on platelet aggregation seems to depend on its concentration and on the nature of the agonist. The strongest inhibition of aggregation was observed in the case of collagen at 1 mg/mL, while there was no observed effect on arachidonic acid-induced aggregation. Moreover, the extract (1 mg/mL) affects the extrinsic, intrinsic, and common pathways of the human blood coagulation cascade by extending significantly (p < 0.001), both PT and APTT times. This study provides evidence that walnut bark extract, by its antiadhesive, antiaggregant, and anticoagulant activities, could be considered as a serious source of biological compounds for the prevention and treatment of thrombosis.