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1.
Open Life Sci ; 19(1): 20220870, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38840895

RESUMO

The microbiome is the synchronised congregation of millions of microbial cells in a particular ecosystem. The rhizospheric, phyllospheric, and endospheric microbial diversity of lower groups of plants like pteridophytes, which includes the Ferns and Fern Allies, have also given numerous alternative opportunities to achieve greener and sustainable agriculture. The broad-spectrum bioactivities of these microorganisms, including bioremediation of heavy metals (HMs) in contaminated soil, have been drawing the attention of agricultural researchers for the preparation of bioformulations for applications in climate-resilient and versatile agricultural production systems. Pteridophytes have an enormous capacity to absorb HMs from the soil. However, their direct application in the agricultural field for HM absorption seems infeasible. At the same time, utilisation of Pteridophyte-associated microbes having the capacity for bioremediation have been evaluated and can revolutionise agriculture in mining and mineral-rich areas. In spite of the great potential, this group of microbiomes has been less studied. Under these facts, this prospective review was carried out to summarise the basic and applied research on the potential of Pteridophyte microbiomes for soil bioremediation and other agricultural applications globally. Gaps have also been indicated to present scopes for future research programmes.

2.
Cureus ; 16(5): e59547, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38826955

RESUMO

Background Platelets are thin disc-shaped blood cells that play a major role in hemostasis, maintenance of vascular integrity, and blood coagulation. Large platelets are more reactive and seen in patients with cardiovascular disease. This study aims to analyze the changes in platelet size of ex vivo activated platelets which phenotypically simulates that of a patient at risk of cardiovascular disease and elucidate the calcium signaling pathway responsible for this change. Methodology Platelets were isolated from adult human blood by differential centrifugation. Calcium was mobilized into platelets by treatment with calcium ionophore A23187 in the presence of Ca2+. Platelet size distribution was analyzed using Coulter Counter Multisizer 4. The following signaling parameters were studied: intracellular Ca2+ measurement (using Fura-2/AM by fluorescence spectrophotometry), Ca2+-dependent thiol protease calpain assay (using fluorogenic substrate t-butoxycarbonyl-Leu-metchloromethylcoumarin in fluorescence microplate reader), platelet-derived microparticles (using FACS Calibur flow cytometry), and cytoskeletal protein talin expression (by western immunoblotting). Results When adult platelets were treated with A23187 and Ca2+, two subcellular populations (<2 µm and between 2-4 µm) were noted. The mean size of the second cell population was significantly higher than that of resting platelets (2.94 ± 0.13 µm vs. 2.82 ± 0.15 µm, t = 4.605, p = 0.00). A23187 treatment led to elevated intracellular Ca2+, release of platelet-derived microparticles, increase in calpain activity, and cytoskeletal talin degradation. These events were inhibited by calpeptin (a specific calpain inhibitor). Conclusions Elevated calcium caused talin degradation by calpain activity. Breakdown of this cytoskeletal protein leads to relative swelling of cells reflected by the increase in platelet size.

3.
Nanoscale Adv ; 6(5): 1497-1506, 2024 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-38419863

RESUMO

In-stent restenosis (ISR) and stent thrombosis (ST) are the most serious complications of coronary angioplasty and stenting. Although the evolution of drug-eluting stents (DES) has significantly restricted the incidence of ISR, they are associated with an enhanced risk of ST. In the present study, we explore the photothermal ablation of a thrombus using a nano-enhanced thermogenic stent (NETS) as a modality for revascularization following ST. The photothermal activity of NETS, fabricated by coating bare metal stents with gold nanorods generating a thin plasmonic film of gold, was found to be effective in rarefying clots formed within the stent lumen in various in vitro assays including those under conditions mimicking blood flow. NETS implanted in the rat common carotid artery generated heat following exposure to a NIR-laser that led to effective restoration of blood flow within the occluded vessel in a model of ferric chloride-induced thrombosis. Our results present a proof-of-concept for a novel photothermal ablation approach by employing coated stents in the non-invasive management of ST.

4.
Cell Commun Signal ; 22(1): 13, 2024 01 03.
Artigo em Inglês | MEDLINE | ID: mdl-38172855

RESUMO

Circulating platelets derived from bone marrow megakaryocytes play a central role in thrombosis and hemostasis. Despite being anucleate, platelets express several proteins known to have nuclear niche. These include transcription factors and steroid receptors whose non-genomic functions are being elucidated in platelets. Quite remarkably, components of some of the best-studied morphogen pathways, namely Notch, Sonic Hedgehog (Shh), and Wnt have also been described in recent years in platelets, which regulate platelet function in the context of thrombosis as well as influence their survival. Shh and Notch pathways in stimulated platelets establish feed-forward loops of autocrine/juxtacrine/paracrine non-canonical signaling that helps perpetuate thrombosis. On the other hand, non-canonical Wnt signaling is part of a negative feedback loop for restricting platelet activation and possibly limiting thrombus growth. The present review will provide an overview of these signaling pathways in general. We will then briefly discuss the non-genomic roles of transcription factors and steroid receptors in platelet activation. This will be followed by an elaborate description of morphogen signaling in platelets with a focus on their bearing on platelet activation leading to hemostasis and thrombosis as well as their potential for therapeutic targeting in thrombotic disorders.


Assuntos
Receptores de Esteroides , Trombose , Humanos , Proteínas Hedgehog/metabolismo , Plaquetas/metabolismo , Ativação Plaquetária , Trombose/metabolismo , Receptores de Esteroides/metabolismo
5.
Microvasc Res ; 152: 104642, 2024 03.
Artigo em Inglês | MEDLINE | ID: mdl-38070864

RESUMO

Filariasis is a chronic disease where parasitic worms survive in human hosts even for decades and lead to complications like lymphedema and elephantiasis. Despite the persistent existence of filarial parasites in human hosts, fatal and thrombotic complications are not known, unlike other parasitic diseases like malaria. This suggests that filarial parasites might be affecting the host's platelet functions. This study was conducted to examine platelet functions in confirmed filariasis patients and healthy controls. Results showed that filariasis patients had larger platelets, inhibited aggregation, and slower speed of aggregation, compared to controls. However, in vivo markers of platelet activation and degranulation (beta thromboglobulin and soluble P-selectin) were not affected. Observations suggested that there is increased platelet turnover, cellular apoptosis and inhibited platelet functions in filariasis patients compared to controls. Platelet function inhibition was not associated with the duration of disease, lymphedema-affected organs, or gender of patients. This study confirms that filarial parasites modulate platelet functions in human hosts.


Assuntos
Filariose Linfática , Linfedema , Humanos , Filariose Linfática/diagnóstico , Filariose Linfática/parasitologia , Doença Crônica
7.
Mol Pharm ; 21(1): 283-302, 2024 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-38126777

RESUMO

Nattokinase (NK), a potent thrombolytic enzyme that dissolves blood clots, is highly used in the treatment of cardiovascular disorders. However, its effective delivery remains demanding because of stability and bioavailability problems owing to its high molecular weight and proteineous nature. In this research, we have developed novel NK-loaded nontargeted liposomes (NK-LS) and targeted liposomes (RGD-NK-LS and AM-NK-LS) by the reverse phase evaporation method. The physiochemical characterizations (particle size, polydispersity index, zeta potential, and morphology) were performed by a Zetasizer, SEM, TEM, and AFM. The Bradford assay and XPS analysis confirmed the successful surface conjugation of the targeting ligands. Platelet interaction studies by CLSM, photon imager optima, and flow cytometry showed significantly higher (P < 0.05) platelet binding affinity of targeted liposomes. In vitro evaluations were performed using human blood and a fibrinolysis study by CLSM imaging demonstrating the potent antithrombotic efficacy of AM-NK-LS. Furthermore, bleeding and clotting time studies revealed that the targeted liposomes were free from any bleeding complications. Moreover, the in vivo FeCl3 model on Sprague-Dawley (SD) rats using a Doppler flow meter and ultrasound/photoacoustic imaging indicated the increased % thrombolysis and potent affinity of targeted liposomes toward the thrombus site. Additionally, in vitro hemocompatibility and histopathology studies demonstrated the safety and biocompatibility of the nanoformulations.


Assuntos
Fibrinolíticos , Técnicas Fotoacústicas , Ratos , Animais , Humanos , Fibrinolíticos/farmacologia , Fibrinolíticos/uso terapêutico , Fibrinólise , Lipossomos/química , Nanomedicina , Ratos Sprague-Dawley , Terapia Trombolítica
8.
Indian J Med Microbiol ; 46: 100432, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37945125

RESUMO

BACKGROUND: The CLSI annual update of its M100 document is eagerly awaited every year. This year's update, the M100-Ed33, was published in February, and will significantly affect clinical practices. OBJECTIVE: To highlight and explain the rationale of the changes and their clinical impact. CONTENT: The major changes this year are mostly focused on PK/PD data, selective and cascade reporting of the antibiotics and therapy related comments. The CLSI has moved away from its classical grouping of antibiotics (A, B, U, O) to a tier-based approach (Tier 1, 2, 3, 4) which will aid in cascade reporting during an antibiotic susceptibility testing (AST). Rather than non-fastidious, fastidious and anaerobe grouping, the tables have been made organism specific. The aminoglycosides breakpoints have been changed for both Enterobacterales and Pseudomonas aeruginosa while for P. aeruginosa, the breakpoints of piperacillin - tazobactam (TZP) are also updated. These updates are mostly based on attainment of drug plasma level for bacterial stasis rather than bactericidal effect of the antibiotics. It is noteworthy, that these breakpoint changes are made, keeping in view that the aminoglycosides for all organisms should be used in combination therapy. For P. aeruginosa, gentamicin has been removed, while amikacin has been restricted for urinary isolates only.


Assuntos
Amicacina , Antibacterianos , Humanos , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Amicacina/farmacologia , Pseudomonas aeruginosa , Combinação Piperacilina e Tazobactam/farmacologia , Testes de Sensibilidade Microbiana
9.
Indian J Med Microbiol ; 46: 100459, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37945132

RESUMO

OBJECTIVES: The purpose of this study was to determine the value of faecal calprotectin (f-CP) in distinguishing between bacterial and viral aetiologies of infective diarrhoea in children attending a tertiary care hospital in Central India. METHODS: Stool samples from children aged 3 months to 10 years who had acute or persistent diarrhoea were processed for microscopy, bacterial culture, and viral antigen detection (Rotavirus and Norovirus). The remaining samples, as well as stool samples from 20 healthy controls, were tested for f-CP using the enzyme linked immunosorbent assay. RESULTS: Among 48 patients, 21 (43.7%) had bacterial diarrhoea, 14 (29.2%) had viral diarrhoea, and 13 (27.1%) had an unidentified aetiology. The median f-CP values were significantly (p â€‹= â€‹0.004) higher in children with bacterial diarrhoea (75.2 â€‹µg/g; IQR-18.75-239.15) than in children with viral diarrhoea (75.2 â€‹µg/g; IQR-123.5-1987.5). Bacterial aetiology could be reliably predicted at the optimum f-CP concentrations of >541 â€‹µg/g and >238.4 â€‹µg/g in children aged 1 and 1-4 years, with an area under the curve of 0.767 and 0.867, respectively, using receiver-operator characteristic analysis. CONCLUSIONS: Faecal calprotectin could reliably distinguish between bacterial and viral aetiologies of diarrhoea in children aged up to four years, but at relatively higher age-specified cut off values.


Assuntos
Infecções Bacterianas , Infecções por Enterovirus , Rotavirus , Criança , Humanos , Complexo Antígeno L1 Leucocitário/análise , Diarreia/diagnóstico , Diarreia/microbiologia , Ensaio de Imunoadsorção Enzimática , Fezes/microbiologia , Biomarcadores
10.
Biomolecules ; 13(11)2023 11 03.
Artigo em Inglês | MEDLINE | ID: mdl-38002291

RESUMO

Two of the most prevalent neurodegenerative disorders (NDDs), Alzheimer's disease (AD) and Parkinson's disease (PD), present significant challenges to healthcare systems worldwide. While the etiologies of AD and PD differ, both diseases share commonalities in synaptic dysfunction, thereby focusing attention on the role of neurotransmitters. The possible functions that platelets may play in neurodegenerative illnesses including PD and AD are becoming more acknowledged. In AD, platelets have been investigated for their ability to generate amyloid-ß (Aß) peptides, contributing to the formation of neurotoxic plaques. Moreover, platelets are considered biomarkers for early AD diagnosis. In PD, platelets have been studied for their involvement in oxidative stress and mitochondrial dysfunction, which are key factors in the disease's pathogenesis. Emerging research shows that platelets, which release glutamate upon activation, also play a role in these disorders. Decreased glutamate uptake in platelets has been observed in Alzheimer's and Parkinson's patients, pointing to a systemic dysfunction in glutamate handling. This paper aims to elucidate the critical role that glutamate receptors play in the pathophysiology of both AD and PD. Utilizing data from clinical trials, animal models, and cellular studies, we reviewed how glutamate receptors dysfunction contributes to neurodegenerative (ND) processes such as excitotoxicity, synaptic loss, and cognitive impairment. The paper also reviews all current medications including glutamate receptor antagonists for AD and PD, highlighting their mode of action and limitations. A deeper understanding of glutamate receptor involvement including its systemic regulation by platelets could open new avenues for more effective treatments, potentially slowing disease progression and improving patient outcomes.


Assuntos
Doença de Alzheimer , Doença de Parkinson , Animais , Humanos , Doença de Parkinson/tratamento farmacológico , Doença de Parkinson/patologia , Doença de Alzheimer/patologia , Ácido Glutâmico , Receptores de Glutamato
11.
FEBS Open Bio ; 13(12): 2342-2355, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37787005

RESUMO

Ayurveda is considered to be one of the most ancient forms of medicine still practiced. The Ayurvedic preparation Raudra Rasa and its derivatives have been widely employed against cancer since the 12th century, but the effect of these traditional formulations on platelet function and signaling has not previously been examined. Here we demonstrate that Raudra Rasa and its derivatives significantly reduce thrombin-induced integrin activation and granule secretion in platelets, as observed by reduced PAC-1 binding and P-selectin externalization, respectively. These formulations also inhibited thrombin-stimulated phosphatidylserine exposure, mitochondrial reactive oxygen species generation, and mitochondrial transmembrane potential in platelets. Consistent with the above, Raudra Rasa significantly reduced thrombin-induced tyrosine phosphorylation of the platelet proteins, as well as phosphorylation of the enzymes AKT and GSK-3ß. In summary, Raudra Rasa inhibits agonist-mediated platelet activation without affecting cell viability, suggesting it may have therapeutic potential as an anti-platelet/anti-thrombotic agent.


Assuntos
Agregação Plaquetária , Trombina , Sobrevivência Celular , Glicogênio Sintase Quinase 3 beta , Ativação Plaquetária , Trombina/antagonistas & inibidores , Trombina/metabolismo , Trombina/farmacologia
12.
ACS Appl Mater Interfaces ; 15(29): 34343-34359, 2023 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-37433149

RESUMO

Breast cancer is the leading cause of death among women globally. Approximately 80% of all breast cancers diagnosed are overexpressed with estrogen receptors (ERs). In this study, we have developed an estrone (Egen)-grafted chitosan-based polymeric nanocarrier for the targeted delivery of palbociclib (PLB) to breast cancer. The nanoparticles (NPs) were prepared by solvent evaporation using the ionic gelation method and characterized for particle size, zeta potential, polydispersity, surface morphology, surface chemistry, drug entrapment efficiency, cytotoxicity assay, cellular uptake, and apoptosis study. The developed PLB-CS NPs and PLB-CS-g-Egen NPs had a particle size of 116.3 ± 1.53 nm and 141.6 ± 1.97 nm, respectively. The zeta potential of PLB-CS NPs and PLB-CS-g-Egen NPs was found to be 18.70 ± 0.416 mV and 12.45 ± 0.574 mV, respectively. The morphological analysis demonstrated that all NPs were spherical in shape and had a smooth surface. An in vitro cytotoxicity assay was performed in estrogen receptor (ER)-expressing MCF7 cells and T47D cells, which suggested that targeted NPs were 57.34- and 30.32-fold more cytotoxic compared to the pure PLB, respectively. Additionally, cell cycle analysis confirmed that cell cycle progression from the G1 into S phase was blocked more efficiently by targeted NPs compared to nontargeted NPs and PLB in MCF7 cells. In vivo pharmacokinetic studies demonstrated that entrapment of the PLB in the NPs improved the half-life and bioavailability by ∼2-3-fold. Further, ultrasound and photoacoustic imaging of DMBA induced breast cancer in the Sprague-Dawley (SD) rat showed that targeted NPs completely vanished breast tumor, reduced hypoxic tumor volume, and suppressed tumor angiogenesis more efficiently compared to the nontargeted NPs and free PLB. Further, in vitro hemocompatibility and histopathology studies suggested that NPs were biocompatible and safe for clinical use.


Assuntos
Quitosana , Nanopartículas , Técnicas Fotoacústicas , Ratos , Animais , Feminino , Estrona , Quitosana/química , Portadores de Fármacos/química , Ratos Sprague-Dawley , Nanopartículas/química , Tamanho da Partícula
13.
Cell Death Differ ; 30(8): 1886-1899, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37301927

RESUMO

Necroptosis is a form of programmed cell death executed by receptor-interacting serine/threonine protein kinase 1 (RIPK1), RIPK3, and mixed lineage kinase domain-like (MLKL). Platelets are circulating cells that play central roles in haemostasis and pathological thrombosis. In this study we demonstrate seminal contribution of MLKL in transformation of agonist-stimulated platelets to active haemostatic units progressing eventually to necrotic death on a temporal scale, thus attributing a yet unrecognized fundamental role to MLKL in platelet biology. Physiological agonists like thrombin instigated phosphorylation and subsequent oligomerization of MLKL in platelets in a RIPK3-independent but phosphoinositide 3-kinase (PI3K)/AKT-dependent manner. Inhibition of MLKL significantly curbed agonist-induced haemostatic responses in platelets that included platelet aggregation, integrin activation, granule secretion, procoagulant surface generation, rise in intracellular calcium, shedding of extracellular vesicles, platelet-leukocyte interactions and thrombus formation under arterial shear. MLKL inhibition, too, prompted impairment in mitochondrial oxidative phosphorylation and aerobic glycolysis in stimulated platelets, accompanied with disruption in mitochondrial transmembrane potential, augmented proton leak and drop in both mitochondrial calcium as well as ROS. These findings underscore the key role of MLKL in sustaining OXPHOS and aerobic glycolysis that underlie energy-intensive platelet activation responses. Prolonged exposure to thrombin provoked oligomerization and translocation of MLKL to plasma membranes forming focal clusters that led to progressive membrane permeabilization and decline in platelet viability, which was prevented by inhibitors of PI3K/MLKL. In summary, MLKL plays vital role in transitioning of stimulated platelets from relatively quiescent cells to functionally/metabolically active prothrombotic units and their ensuing progression to necroptotic death.


Assuntos
Plaquetas , Proteínas Quinases , Proteínas Quinases/metabolismo , Plaquetas/metabolismo , Necroptose , Cálcio/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Trombina/farmacologia , Trombina/metabolismo , Morte Celular , Proteína Serina-Treonina Quinases de Interação com Receptores/metabolismo
14.
JACC Asia ; 3(2): 185-197, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37181385

RESUMO

Intravascular lithotripsy can be used as an effective therapy for lesion preparation in severely calcified lesions. The mechanism, as shown by optical coherence tomography, is calcium fractures. The aforementioned modification is performed with minimal risk of perforation, no-reflow and a low incidence of flow-limiting dissection and myocardial infarctions. Other techniques, such as cutting or scoring balloons and rotational atherectomy have also been shown to increase luminal diameter, but other complications, such as distal embolization, induced by these treatment modalities, are a source of concern. This review describes a single-center study of all-comer patients, including those with complex characteristics. This therapy is very effective, with a very low risk of complications. In this article, we characterize the mechanism of action of the intravascular lithotripsy catheter, its optical coherence tomography validation, clinical applications, and comparison with other calcium-modifying technologies, as well as future directions, which can be used to improve the technology.

15.
Sci Rep ; 13(1): 7615, 2023 05 10.
Artigo em Inglês | MEDLINE | ID: mdl-37165007

RESUMO

Platelet-monocyte (PMA) and platelet-neutrophil aggregations (PNA) play critical roles in the evolution of acute ischemic stroke (AIS). The present study investigates the mechanistic basis of platelet responsiveness in cryptogenic stroke compared with cardioembolic stroke. Platelet from 16 subjects, each from cryptogenic and cardioembolic stroke groups and 18 age-matched healthy controls were subjected to different investigations. Compared to healthy controls, platelet-monocyte and platelet-neutrophil interactions were significantly elevated in cryptogenic (2.7 and 2.1 times) and cardioembolic stroke (3.9 and 2.4 times). P-selectin expression on platelet surface was 1.89 and 2.59 times higher in cryptogenic and cardioembolic strokes, respectively, compared to healthy control. Cell population with [Ca2+i] in either stroke group was significantly outnumbered (by 83% and 72%, respectively, in cryptogenic and cardioembolic stroke) in comparison to healthy controls. Noteworthy, TEG experiment revealed that the cryptogenic stroke exhibited significant decline in Reaction Time (R) and amplitude of 20 mm (K) (by 32% and 33%, respectively) while thrombin burst (α-angle) was augmented by 12%, which reflected substantial boost in thrombus formation in cryptogenic stroke. Although TEG analysis reveals a state of hypercoagulability in patients with cryptogenic stroke. However, platelets from both stroke subtypes switch to a 'hyperactive' phenotype.


Assuntos
AVC Embólico , AVC Isquêmico , Acidente Vascular Cerebral , Trombose , Humanos , AVC Isquêmico/complicações , Acidente Vascular Cerebral/complicações , Acidente Vascular Cerebral/genética , Trombose/complicações , Plaquetas , Fatores de Risco
16.
Metabolism ; 145: 155596, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37244415

RESUMO

Platelets are circulating cells central to haemostasis that follows vessel injury, as well as thrombosis that ensues as a consequence of pathological stasis or plaque rupture. Platelet responses to various stimuli that mediate these processes are all energy-intensive. Hence, platelets need to adapt their energy metabolism to fulfil the requirements of clot formation while overcoming the adversities of the thrombus niche such as restricted access to oxygen and nutrient. In the present review, we describe the changes in energy metabolism of platelets upon agonist challenge and their underlying molecular mechanisms. We briefly discuss the metabolic flexibility and dependency of stimulated platelets in terms of choice of energy substrates. Finally, we discuss how targeting the metabolic vulnerabilities of stimulated platelets such as aerobic glycolysis and/or beta oxidation of fatty acids could forestall platelet activation and thrombus formation. Thus, we present a case for modulating platelet energy metabolism using small-molecules as a novel anti-platelet strategy in the management of vaso-occlusive disorders like acute myocardial infarction, ischemic stroke, deep vein thrombosis and pulmonary embolism.


Assuntos
Plaquetas , Trombose , Humanos , Metabolismo Energético , Ácidos Graxos/metabolismo , Ativação Plaquetária , Agregação Plaquetária
17.
Artigo em Inglês | MEDLINE | ID: mdl-36965822

RESUMO

AIM: A simple and reliable method for diagnosing COVID 19 infections is the needed. The role of saliva in the transmission of the infection has already been established. METHOD: Saliva and nasopharyngeal swabs from patients suspected to have COVID 19 infections were taken simultaneously, and the results of the RT-PCR were compared. RESULT: Total 405 samples were collected, of which 250 males and 155 females. In the 391 samples included for analysis, 370 (94.63%) samples were found to have concordance results, and 21 (5.37%) samples had discordant results. CONCLUSION: The use of saliva to diagnose COVID 19 infection is reliable, and its use can be recommended.


Assuntos
COVID-19 , SARS-CoV-2 , Feminino , Masculino , Humanos , COVID-19/diagnóstico , Saliva , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Nasofaringe , Teste para COVID-19
18.
FASEB J ; 37(2): e22768, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36624703

RESUMO

Platelet mitochondria possess remarkable plasticity for oxidation of energy substrates, where metabolic dependency on glucose or fatty acids is higher than glutamine. Since platelets metabolize nearly the entire pool of glucose to lactate rather than fluxing through mitochondrial tricarboxylic acid cycle, we posit that majority of mitochondrial ATP, which is essential for platelet granule secretion and thrombus formation, is sourced from oxidation of fatty acids. We performed a comprehensive analysis of bioenergetics and function of stimulated platelets in the presence of etomoxir, trimetazidine and oxfenicine, three pharmacologically distinct inhibitors of ß-oxidation. Each of them significantly impaired oxidative phosphorylation in unstimulated as well as thrombin-stimulated platelets leading to a small but consistent drop in ATP level in activated cells due to a lack of compensation from glycolytic ATP. Trimetazidine and oxfenicine attenuated platelet aggregation, P-selectin externalization and integrin αIIb ß3 activation. Both etomoxir and trimetazidine impeded agonist-induced dense granule release and platelet thrombus formation on collagen under arterial shear. The effect of inhibitors on platelet aggregation and dense granule release was dose- and incubation time- dependent with significant inhibition at higher doses and prolonged incubation times. Neither of the inhibitors could protect mice from collagen-epinephrine-induced pulmonary embolism or prolong mouse tail bleeding times. However, mice pre-administered with etomoxir, trimetazidine and oxfenicine were protected from ferric chloride-induced mesenteric thrombosis. In conclusion, ß-oxidation of fatty acids sustains ATP level in stimulated platelets and is therefore essential for energy-intensive agonist-induced platelet responses. Thus, fatty acid oxidation may constitute an attractive therapeutic target for novel antiplatelet agents.


Assuntos
Trombose , Trimetazidina , Camundongos , Animais , Ácidos Graxos/metabolismo , Trimetazidina/efeitos adversos , Trimetazidina/metabolismo , Plaquetas/metabolismo , Ativação Plaquetária , Agregação Plaquetária , Trombose/induzido quimicamente , Trombose/prevenção & controle , Trombose/metabolismo , Complexo Glicoproteico GPIIb-IIIa de Plaquetas/efeitos adversos , Complexo Glicoproteico GPIIb-IIIa de Plaquetas/metabolismo , Fosforilação Oxidativa , Colágeno/metabolismo , Trifosfato de Adenosina/metabolismo , Glucose/metabolismo
20.
J. Transcatheter Interv ; 31: eA202302, 2023. ilus; tab
Artigo em Inglês, Português | LILACS-Express | LILACS | ID: biblio-1442691

RESUMO

Por várias décadas, a revascularização do miocárdio foi considerada o tratamento padrão-ouro de lesões não protegidas do tronco da coronária esquerda. No entanto, a acessibilidade anatômica e o grande calibre dos vasos tornam as lesões de tronco uma opção atraente para a intervenção coronária percutânea. A aplicação dessa intervenção nesse cenário foi expandida ainda mais como resultado da introdução de novos stents farmacológicos, com rápidos avanços em técnicas, dispositivos e farmacoterapias adjuvantes. As evidências atuais têm demonstrado que pacientes com complexidade coronariana baixa ou intermediária têm desfechos similares com a intervenção coronária percutânea ou a revascularização cirúrgica do miocárdio por até 10 anos. O tratamento das lesões da bifurcação do tronco da coronária esquerda continua tecnicamente complexo, apesar dos recentes avanços. A abordagem provisional é a estratégia padrão na maioria dos tipos de lesões da bifurcação do tronco da coronária esquerda. No entanto, algumas lesões complexas da bifurcação do tronco da coronária esquerda justificariam uma técnica eletiva com implante de dois stents. A abordagem integrada, que incorpora técnicas dedicadas, uma avaliação fisiológica e anatômica adjuvante e agentes farmacológicos, é fundamental para abordar com sucesso esse desafio ímpar e melhorar os desfechos clínicos.


For several decades coronary bypass grafting has been considered the gold standard treatment for unprotected left main coronary artery lesions. However, the anatomic accessibility and the large caliber of the vessel render the percutaneous coronary intervention a very attractive treatment option for left main coronary artery lesions. The use of percutaneous coronary intervention in this subset of lesions has been further expanded as a result of the introduction of newer drug-eluting stents along with rapid advancements in techniques, devices, and adjunctive pharmacotherapies. The current evidence has demonstrated that patients with low or intermediate coronary complexity treated with percutaneous coronary intervention or coronary bypass grafting have comparable outcomes, for up to 10 years. Treatment of left main bifurcation lesions remains technically demanding despite recent developments. The provisional approach is the default strategy in most types of left main bifurcation lesions. However, a few complex left main bifurcation lesions would warrant an elective two-stent technique. An integrated approach incorporating custom- tailored techniques, adjunctive physiological and morphologic evaluation, and pharmacologic agents is critical to tackle this unique challenge and improve clinical outcomes.

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