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JBRA Assisted Reproduction Jun 2024To evaluate if it possible to improve ovarian reserve parameters and oocyte retrieval in poor responders who undergo intraovarian injection of platelet-rich plasma (PRP).
OBJECTIVE
To evaluate if it possible to improve ovarian reserve parameters and oocyte retrieval in poor responders who undergo intraovarian injection of platelet-rich plasma (PRP).
METHODS
Prospective cohort study. We included 148 poor responders who underwent PRP injection between October 2021 and December 2022 in our institution, comparing pre and post PRP ovarian function. In addition, the IVF outcomes of a subgroup of patients was studied after the intervention in contrast with the previous treatment.
RESULTS
An improvement in ovarian reserve was observed in relation to previous values: FSH (13.57 vs. 11.32, p=0.11), AMH (0.39 vs. 0.48, p=0.06), antral follicle count (3.98 vs. 5.75, p<0.001); as well as a higher number of oocytes retrieved (2.63 vs. 3.65, p=0.01) and produced embryos (1.64 vs. 2.22, p=0.03); without a great impact on pregnancy rates.
CONCLUSIONS
Although experimental, intraovarian PRP could restore ovarian function and be postulated as an alternative to oocyte donation in patients with low ovarian reserve who do not accept this treatment. There is a lack of randomized controlled trials to support these findings.
PubMed: 38838163
DOI: 10.5935/1518-0557.20240031 -
Open Biology Jun 2024Platelets are blood cells derived from megakaryocytes that play a central role in regulating haemostasis and vascular integrity. The microtubule cytoskeleton of... (Review)
Review
Platelets are blood cells derived from megakaryocytes that play a central role in regulating haemostasis and vascular integrity. The microtubule cytoskeleton of megakaryocytes undergoes a critical dynamic reorganization during cycles of endomitosis and platelet biogenesis. Quiescent platelets have a discoid shape maintained by a marginal band composed of microtubule bundles, which undergoes remarkable remodelling during platelet activation, driving shape change and platelet function. Disrupting or enhancing this process can cause platelet dysfunction such as bleeding disorders or thrombosis. However, little is known about the molecular mechanisms underlying the reorganization of the cytoskeleton in the platelet lineage. Recent studies indicate that the emergence of a unique platelet tubulin code and specific pathogenic tubulin mutations cause platelet defects and bleeding disorders. Frequently, these mutations exhibit dominant negative effects, offering valuable insights into both platelet disease mechanisms and the functioning of tubulins. This review will highlight our current understanding of the role of the microtubule cytoskeleton in the life and death of platelets, along with its relevance to platelet disorders.
Topics: Humans; Blood Platelets; Megakaryocytes; Cytoskeleton; Microtubules; Tubulin; Animals; Blood Platelet Disorders; Mutation
PubMed: 38835242
DOI: 10.1098/rsob.240041 -
Platelets Dec 2024The purpose of this study is to investigate the molecular interactions and potential therapeutic uses of Eltrombopag (EPAG), a small molecule that activates the cMPL...
The purpose of this study is to investigate the molecular interactions and potential therapeutic uses of Eltrombopag (EPAG), a small molecule that activates the cMPL receptor. EPAG has been found to be effective in increasing platelet levels and alleviating thrombocytopenia. We utilized computational techniques to predict and confirm the complex formed by the ligand (EPAG) and the Thrombopoietin receptor (TPO-R) cMPL, elucidating the role of RAS, JAK-2, STAT-3, and other essential elements for downstream signaling. Molecular dynamics (MD) simulations were employed to evaluate the stability of the ligand across specific proteins, showing favorable characteristics. For the first time, we examined the presence of TPO-R in human umbilical cord mesenchymal stem cells (hUCMSC) and human gingival mesenchymal stem cells (hGMSC) proliferation. Furthermore, treatment with EPAG demonstrated angiogenesis and vasculature formation of endothelial lineage derived from both MSCs. It also indicated the activation of critical factors such as RUNX-1, GFI-1b, VEGF-A, MYB, GOF-1, and FLI-1. Additional experiments confirmed that EPAG could be an ideal molecule for protecting against UVB radiation damage, as gene expression (JAK-2, ERK-2, MCL-1, NFkB, and STAT-3) and protein CD90/cMPL analysis showed TPO-R activation in both hUCMSC and hGMSC. Overall, EPAG exhibits significant potential in treating radiation damage and mitigating the side effects of radiotherapy, warranting further clinical exploration.
Topics: Humans; Pyrazoles; Benzoates; Receptors, Thrombopoietin; Hydrazones; Mesenchymal Stem Cells; Hydrazines; Molecular Dynamics Simulation; Angiogenesis
PubMed: 38832545
DOI: 10.1080/09537104.2024.2359028 -
Frontiers in Veterinary Science 2024Physical exercise has an activating effect on platelet function that differs between trained and untrained subjects, depending on the type of exercise and training...
Physical exercise has an activating effect on platelet function that differs between trained and untrained subjects, depending on the type of exercise and training status. In humans, soluble P-selectin (sP-sel) and platelet-derived extracellular vesicles (PEVs) are considered reliable markers of platelet activation during exercise. In untrained humans, they increase after transient physical exercise, whereas long-term training induces a decrease in their resting levels due to an improved ability to adapt to hemodynamic changes. The aim of this study was to assess whether circulating levels of sP-sel and PEVs may be useful markers to explore platelet function in never-trained Thoroughbreds during their first 4 months of incremental training. A total of 29 clinically healthy, untrained Thoroughbreds (17 males and 12 females) were enrolled. All horses were trained with the same training schedule (90 days). Blood samples were collected on the day the training program began (T0), 30 days (T30), and 90 days (T90) after its incremental increase to quantify platelet count, sP-sel (horse enzyme-linked immunosorbent assay) and PEVs (flow cytometry). Statistical analysis was performed using RM one-way analysis of variance with the Geisser-Greenhouse correction. Soluble P-selectin tended to increase at T30 compared with T0, while T90 levels returned to baseline values. Significantly higher circulating levels of PEVs CD61/AnnV were observed at T30 and T90 compared to baseline confirming platelet hyperactivity. The detection and quantification of sP-sel and PEVs in equine racehorses during the training period appears to be a promising tool to study exercise-induced primary hemostatic changes and may provide an important marker for exercise selection.
PubMed: 38831955
DOI: 10.3389/fvets.2024.1395423 -
ESC Heart Failure Jun 2024Left ventricular assist device (LVAD) implantation, a therapy for end-stage heart failure, is associated with platelet (PLT) activation. This study aims to evaluate the...
AIMS
Left ventricular assist device (LVAD) implantation, a therapy for end-stage heart failure, is associated with platelet (PLT) activation. This study aims to evaluate the prognostic impact of PLT count in patients with LVAD implantation.
METHODS AND RESULTS
Data from the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) registry were investigated, and patients were divided into three groups according to tertiles. The dynamic change of PLT counts and its associations with long-term outcomes were analysed. The primary outcome was long-term mortality. A total of 19 517 patients who received the first continuous-flow LVAD were identified from the INTERMACS registry. The PLT count underwent a dynamic change towards normalization after LVAD implantation. Compared with intermediate, both high (hazard ratio [HR], 1.09, 95% confidence interval [CI]: 1.01 to 1.17, P = 0.033) and low (HR, 1.18, 95% CI: 1.10 to 1.27, P < 0.001) pre-implant PLT counts were associated with an increased risk of 2 year mortality. Compared with intermediate, a high post-implant PLT count was associated with an increased risk of 4 year mortality (HR, 1.38, 95% CI: 1.26 to 1.52, P < 0.001). Besides, both pre- and post-implant PLT counts exhibit a U-shaped association with the risk of mortality.
CONCLUSIONS
LVAD implantation could improve the PLT count towards normalization. Abnormal pre-/post-implant PLT counts were independently associated with increased risks of long-term mortality.
PubMed: 38831637
DOI: 10.1002/ehf2.14856 -
Archives of Razi Institute Dec 2023Snake venoms are rich in valuable substances that have medical potential in the diagnosis and treatment of hemostatic diseases. The present paper was aimed at the...
Snake venoms are rich in valuable substances that have medical potential in the diagnosis and treatment of hemostatic diseases. The present paper was aimed at the purification and functional characterization basis of a thrombin-like enzyme and its role in the functioning of the coagulation cascade and platelet aggregation pathway. A thrombin-like serine protease was purified from the Iranian venom (TLIECV), employing a one-step chromatographic procedure. This peptide was collected in high yield and purity by a single chromatographic step using RP-HPLC equipped with a C column. This peptide showed a 3000 Da molecular weight in gel-electrophoresis. Evidence in the SDS-PAGE gel has confirmed high recovery of fraction in optimal terms. Subsequently, this peptide was identified via its intact molecular mass and peptide mass fingerprint (PMF) using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/MS). Multiple sequence alignments were performed by ClustalW, the Bioedit software. Molegro Data Modeller (MDM) 3.0 software was used to predict the putative tertiary structure of the peptide. The enzyme possessed fibrinogenolytic, procoagulant, and aggregation inducer properties. Moreover, the SDS-PAGE (12%) was applied to examine fibrinogenolytic function. The purified enzyme degraded the Aα chain of fibrinogen while the Bβ and γ chains were not digested. According to that, the deficient human plasma in factor X and normal human plasma were also coagulated by TLIECV, it takes part in the common and intrinsic routes of the coagulation cascade. These findings proved that TLIECV is a serine protease identical to procoagulant thrombin-like snake venom proteases; however, it specifically releases the Aα chain of bovine fibrinogen. Because of its function to make up for the deficiency of factor X and its platelet aggregation inducer property, TLIECV could be considered a molecular impact to reveal the hemostasis mechanisms.
Topics: Viperidae; Animals; Viper Venoms; Iran; Thrombin; Platelet Aggregation; Humans; Electrophoresis, Polyacrylamide Gel; Amino Acid Sequence; Echis; Venomous Snakes
PubMed: 38828174
DOI: 10.32592/ARI.2023.78.6.1822 -
Neural Regeneration Research Feb 2025Subretinal fibrosis is the end-stage sequelae of neovascular age-related macular degeneration. It causes local damage to photoreceptors, retinal pigment epithelium, and...
Subretinal fibrosis is the end-stage sequelae of neovascular age-related macular degeneration. It causes local damage to photoreceptors, retinal pigment epithelium, and choroidal vessels, which leads to permanent central vision loss of patients with neovascular age-related macular degeneration. The pathogenesis of subretinal fibrosis is complex, and the underlying mechanisms are largely unknown. Therefore, there are no effective treatment options. A thorough understanding of the pathogenesis of subretinal fibrosis and its related mechanisms is important to elucidate its complications and explore potential treatments. The current article reviews several aspects of subretinal fibrosis, including the current understanding on the relationship between neovascular age-related macular degeneration and subretinal fibrosis; multimodal imaging techniques for subretinal fibrosis; animal models for studying subretinal fibrosis; cellular and non-cellular constituents of subretinal fibrosis; pathophysiological mechanisms involved in subretinal fibrosis, such as aging, infiltration of macrophages, different sources of mesenchymal transition to myofibroblast, and activation of complement system and immune cells; and several key molecules and signaling pathways participating in the pathogenesis of subretinal fibrosis, such as vascular endothelial growth factor, connective tissue growth factor, fibroblast growth factor 2, platelet-derived growth factor and platelet-derived growth factor receptor-β, transforming growth factor-β signaling pathway, Wnt signaling pathway, and the axis of heat shock protein 70-Toll-like receptors 2/4-interleukin-10. This review will improve the understanding of the pathogenesis of subretinal fibrosis, allow the discovery of molecular targets, and explore potential treatments for the management of subretinal fibrosis.
PubMed: 38819041
DOI: 10.4103/NRR.NRR-D-23-01642 -
Journal of Thrombosis and Haemostasis :... May 2024COVID-19 can cause profound inflammation and coagulopathy, and while many mechanisms have been proposed, there is no known common pathway leading to a prothrombotic...
BACKGROUND
COVID-19 can cause profound inflammation and coagulopathy, and while many mechanisms have been proposed, there is no known common pathway leading to a prothrombotic state.
OBJECTIVES
From the beginning of the COVID-19 pandemic, elevated levels of extracellular histones have been found in plasma of patients infected with SARS-CoV-2. We hypothesized that platelet activation triggered by extracellular histones might represent a unifying mechanism leading to increased thrombin generation and thrombosis.
METHODS
We utilized blood samples collected from an early clinical trial of hospitalized COVID-19 patients (NCT04360824) and recruited healthy subjects as controls. Using plasma samples, we measured the procoagulant and prothrombotic potential of circulating extracellular histones and extracellular vesicles (EVs). Platelet prothrombotic activity was assessed via thrombin generation potential and platelet thrombus growth. Circulating EVs were assessed for thrombin generation potential in vitro in plasma and enhancement of thrombotic susceptibility in vivo in mice.
RESULTS
Compared with controls, COVID-19 patients had elevated plasma levels of citrullinated histone H3, cell-free DNA, nucleosomes, and EVs. Plasma from COVID-19 patients promoted platelet activation, platelet-dependent thrombin generation, thrombus growth under venous shear stress, and release of platelet-derived EVs. These prothrombotic effects of COVID-19 plasma were inhibited by an RNA aptamer that neutralizes both free and DNA-bound histones. EVs isolated from COVID-19 plasma enhanced thrombin generation in vitro and potentiated venous thrombosis in mice in vivo.
CONCLUSION
We conclude that extracellular histones and procoagulant EVs drive the prothrombotic state in COVID-19 and that histone-targeted therapy may prove beneficial.
PubMed: 38815756
DOI: 10.1016/j.jtha.2024.05.019 -
The role of PALLD-STAT3 interaction in megakaryocyte differentiation and thrombocytopenia treatment.Haematologica May 2024Impaired differentiation of megakaryocytes constitutes the principal etiology of thrombocytopenia. The signal transducer and activator of transcription 3 (STAT3) is a...
Impaired differentiation of megakaryocytes constitutes the principal etiology of thrombocytopenia. The signal transducer and activator of transcription 3 (STAT3) is a crucial transcription factor in regulating megakaryocyte differentiation, yet the precise mechanism of its activation remains unclear. PALLD, an actin-associated protein, has been increasingly recognized for its essential functions in multiple biological processes. This study revealed that megakaryocyte/plateletspecific knockout of PALLD in mice exhibited thrombocytopenia due to diminished platelet biogenesis. In megakaryocytes, PALLD deficiency led to impaired proplatelet formation and polyploidization, ultimately weakening their differentiation for platelet production. Mechanistic studies demonstrated that PALLD bound to STAT3 and interacted with its DNA-binding domain (DBD) and Src homology 2 (SH2) domain via Immunoglobulin domain 3 (Ig3). Moreover, the absence of PALLD attenuated STAT3 Y705 phosphorylation and impeded STAT3 nuclear translocation. Based on the PALLD-STAT3 binding sequence, we designed a peptide C-P3, which can facilitate megakaryocyte differentiation and accelerate platelet production in vivo. In conclusion, this study highlights the pivotal role of PALLD in megakaryocyte differentiation and proposes a novel approach for treating thrombocytopenia by targeting the PALLD-STAT3 interaction.
PubMed: 38813732
DOI: 10.3324/haematol.2024.285242 -
Research and Practice in Thrombosis and... Mar 2024Assessment of platelet function is key in diagnosing bleeding disorders and evaluating antiplatelet drug efficacy. However, there is a prevailing "one-size-fits-all"...
BACKGROUND
Assessment of platelet function is key in diagnosing bleeding disorders and evaluating antiplatelet drug efficacy. However, there is a prevailing "one-size-fits-all" approach in the interpretation of measures of platelet reactivity, with arbitrary cutoffs often derived from healthy volunteer responses.
OBJECTIVES
Our aim was to compare well-used platelet reactivity assays.
METHODS
Blood and platelet-rich plasma obtained from the Framingham Heart Study ( = 3429) were assayed using a range of agonists in 5 platelet assays: light transmission aggregometry, Optimul aggregometry, Multiplate impedance aggregometry (Roche Diagnostics), Total Thrombus-Formation Analysis System, and flow cytometry. Using linear mixed-effect models, we determined the contribution of preanalytical and technical factors that modulated platelet reactivity traits.
RESULTS
A strong intra-assay correlation of platelet traits was seen in all assays, particularly Multiplate velocity ( = 0.740; ristocetin vs arachidonic acid). In contrast, only moderate interassay correlations were observed ( = 0.375; adenosine diphosphate Optimul E vs light transmission aggregometry large area under the curve). As expected, antiplatelet drugs strongly reduced platelet responses, with aspirin use primarily targeting arachidonic acid-induced aggregation, and explained substantial variance (β = -1.735; = 4.59 × 10; variance proportion = 46.2%) and P2Y antagonists blocking adenosine diphosphate responses (β = -1.612; = 6.75 × 10; variance proportion = 2.1%). Notably, female sex and older age were associated with enhanced platelet reactivity. Fasting status and deviations from standard venipuncture practices did not alter platelet reactivity significantly. Finally, the agonist batch, phlebotomist, and assay technician (more so for assays that require additional sample manipulation) had a moderate to large effect on measured platelet reactivity.
CONCLUSION
Caution must be exercised when extrapolating findings between assays, and the use of standard ranges must be medication-specific and sex-specific at a minimum. Researchers should also consider preanalytical and technical variables when designing experiments and interpreting platelet reactivity measures.
PubMed: 38813256
DOI: 10.1016/j.rpth.2024.102406