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1.
J Hazard Mater ; 421: 126690, 2022 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-34315019

RESUMO

Shellfish toxins are derived from harmful algae and are easily accumulated in environment and marine food through the food chain, exposing high risks on human health. Preliminary rapid screening is one of the most effective monitoring ways to reduce the potential risks; however, the traditional methods encounter with many limitations, such as complicated procedures, low sensitivity and specificity, and ethical problems. Alternatively, bioaffinity sensors are proposed and draw particular attention. Among them, the aptasensors are springing up and emerging as superior alternatives in recent years, exhibiting high practicability to analyze shellfish toxins in real samples in the marine food chain. Herein, the latest research progresses of aptasensors towards shellfish toxins in the marine food chain in the past five years was reviewed for the first time, in terms of the aptamers applied in these aptasensors, construction principles, signal transduction techniques, response types, individual performance properties, practical applications, and advantages/disadvantages of these aptasensors. Synchronously, critical discussions were given and future perspectives were prospected. We hope this review can serve as a powerful reference to promote further development and application of aptasensors to monitor shellfish toxins, as well as other analytes with similar demands.


Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Contaminação de Alimentos/análise , Toxinas Marinhas/análise , Cadeia Alimentar , Humanos , Frutos do Mar
2.
Talanta ; 238(Pt 1): 123032, 2022 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-34857350

RESUMO

Herein, the split aptamers, chitosan oligosaccharide, and AuNPs were combined as nanocomposites that present different formations to develop a label-free colorimetric aptasensor for rapid detection of small molecules. Kanamycin was chosen as a model target. Computational studies were performed to assist in the design of orientated immobilization of the split aptamers onto the AuNPs surface. Chitosan oligosaccharide was initially applied as an aggregation inducer of AuNPs, and chitopentaose was screened as the optimal. Under optimized conditions, the proposed aptasensor showed high sensitivity and selectivity, with a limit of detection of 20.58 nM, a linear range of 25-800 nM, and good recoveries of 98.49-104.9% and 85.69-107.0% when employed to detect kanamycin in tap water and milk samples, respectively. Only 55 min was needed for the whole assay. More importantly, this study can serve as a novel and robust reference for the aptasensing detection of other small molecules.


Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Quitosana , Nanopartículas Metálicas , Nanocompostos , Colorimetria , Ouro , Canamicina , Limite de Detecção , Oligossacarídeos
3.
J Healthc Eng ; 2021: 5230666, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34900193

RESUMO

Early screening is an important way to reduce the incidence and mortality of colorectal cancer (CRC). Fecal DNA testing stands out among many screening methods due to its high sensitivity. However, at this stage, researchers have not found a high-efficiency method for fecal DNA extraction. To this end, this work carried out a new round of exploration. Here, this experiment synthesized a kind of nanomagnetic beads (NH2-SiO2@Fe3O4) with good stability for nucleic acid extraction. A comparative study with the centrifugal adsorption column method revealed the significant advantages of the magnetic bead method in extracting fecal DNA. The DNA extracted by the magnetic bead method is of high purity, can also achieve high-throughput tests, and is more suitable for polymerase chain reaction detection, greatly simplifying the stool DNA detection process and providing a basis for the widespread promotion of early screening.


Assuntos
Neoplasias Colorretais , Ácidos Nucleicos , Neoplasias Colorretais/diagnóstico , Detecção Precoce de Câncer , Humanos , Óxidos , Dióxido de Silício
4.
J Immunol Res ; 2021: 6880036, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34646889

RESUMO

Tobacco smoke is an established risk factor for thoracic aortic aneurysms and dissections (TAAD). However, little is known about its underlying mechanisms due to the lack of validated animal models. The present study developed a mouse model that may be utilized to investigate exacerbation of TAAD formation by mimetics of tobacco smoke. TAADs were created via inducible deletion of smooth muscle cell-specific Tgfbr2 receptors. Using this model, the first set of experiments evaluated the efficacy of nicotine salt (34.0 mg/kg/day), nicotine free base (NFB, 5.0 mg 90-day pellets), and cigarette smoke extract (0.1 ml/mouse/day). Compared with their respective control groups, only NFB pellets promoted TAAD dilation (23 ± 3% vs. 12 ± 2%, P = 0.014), and this efficacy was achieved at a cost of >50% acute mortality. Infusion of NFB with osmotic minipumps at extremely high, but nonlethal, doses (15.0 or 45.0 mg/kg/day) failed to accelerate TAAD dilation. Interestingly, costimulation with ß-aminopropionitrile (BAPN) promoted TAAD dilation and aortic rupture at dosages of 3.0 and 45.0 mg/kg/day, respectively, indicating that BAPN sensitizes the response of TAADs to NFB. In subsequent analyses, the detrimental effects of NFB were associated with clustering of macrophages, neutrophils, and T-cells in areas with structural destruction, enhanced matrix metalloproteinase- (MMP-) 2 production, and pathological angiogenesis with attenuated fibrosis in the adventitia. In conclusion, modeling nicotine exacerbation of TAAD formation requires optimization of chemical form, route of delivery, and dosage of the drug as well as the pathologic complexity of TAADs. Under the optimized conditions of the present study, chronic inflammation and adventitial mal-remodeling serve as critical pathways through which NFB exacerbates TAAD formation.

7.
PLoS Comput Biol ; 17(6): e1009137, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-34191797

RESUMO

The pig is commonly used as an experimental model of human heart disease, including for the study of mechanisms of arrhythmia. However, there exist differences between human and porcine cellular electrophysiology: The pig action potential (AP) has a deeper phase-1 notch, a longer duration at 50% repolarization, and higher plateau potentials than human. Ionic differences underlying the AP include larger rapid delayed-rectifier and smaller inward-rectifier K+-currents (IKr and IK1 respectively) in humans. AP steady-state rate-dependence and restitution is steeper in pigs. Porcine Ca2+ transients can have two components, unlike human. Although a reliable computational model for human ventricular myocytes exists, one for pigs is lacking. This hampers translation from results obtained in pigs to human myocardium. Here, we developed a computational model of the pig ventricular cardiomyocyte AP using experimental datasets of the relevant ionic currents, Ca2+-handling, AP shape, AP duration restitution, and inducibility of triggered activity and alternans. To properly capture porcine Ca2+ transients, we introduced a two-step process with a faster release in the t-tubular region, followed by a slower diffusion-induced release from a non t-tubular subcellular region. The pig model behavior was compared with that of a human ventricular cardiomyocyte (O'Hara-Rudy) model. The pig, but not the human model, developed early afterdepolarizations (EADs) under block of IK1, while IKr block led to EADs in the human but not in the pig model. At fast rates (pacing cycle length = 400 ms), the human cell model was more susceptible to spontaneous Ca2+ release-mediated delayed afterdepolarizations (DADs) and triggered activity than pig. Fast pacing led to alternans in human but not pig. Developing species-specific models incorporating electrophysiology and Ca2+-handling provides a tool to aid translating antiarrhythmic and arrhythmogenic assessment from the bench to the clinic.


Assuntos
Modelos Cardiovasculares , Miócitos Cardíacos/fisiologia , Potenciais de Ação , Animais , Arritmias Cardíacas/fisiopatologia , Sinalização do Cálcio , Biologia Computacional , Simulação por Computador , Fenômenos Eletrofisiológicos , Ventrículos do Coração/citologia , Humanos , Técnicas In Vitro , Modelos Animais , Técnicas de Patch-Clamp , Sus scrofa
8.
Food Chem ; 364: 130361, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34153597

RESUMO

The residual tetracyclines in food are frequently applied as the model compounds to develop aptasensors. Until now, more than 100 advanced aptasensors towards tetracyclines have been developed and published in English. This review summarizes and discusses comprehensively these advanced aptasensors, in terms of the principle designs, applied frontier transducers/materials, working performance, and advantages/disadvantages. The aptasensors are classified according to the inherent transduction techniques, i.e., optics, optics-electricity, optics-mass, and electricity-mass. Moreover, the present challenges such as the limited specificity and limited affinity of the aptamers, the future prospects and trends such as further combination with other advanced materials and technologies, and the urgent need of expanding the practical application were discussed and prospected. We hope this review can serve as a powerful tool for both tracing the development progresses of aptasensors and providing adequate references for further development of aptasensing methods for food-related analytes.


Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Antibacterianos , Análise de Alimentos , Tetraciclinas
9.
Anal Chim Acta ; 1173: 338710, 2021 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-34172145

RESUMO

Saxitoxin (STX) is a small molecule toxin (Mw. ca. 299 g/mol) with high acute toxicity, and it has urgent need of facile analytical methods. Herein, a competitive colorimetric aptasensor was developed for highly sensitive detection of STX. An anti-STX aptamer was hybridized with a complementary strand on the magnetic beads and was competitively bound by STX. The supernatant containing the aptamer binding to STX was obtained by magnetic separation, which could trigger hybridization chain reaction (HCR) to generate rigid double stranded DNAs (dsDNAs) with sticky end and variable length. These HCR-dsDNAs were found to be able to facilitate significant enhancement on the peroxidase-like catalytic capability of AuNPs nanozyme towards 3,3,5,5-tetramethylbenzidine (TMB). The concentration of STX was responded in a "turn on" mode, based on the amplified colorimetric transduction thereof. The aptasensor realized high sensitivity, with a limit of detection (LOD) as low as 42.46 pM. Moreover, a wide linear detection range of 78.13-2500 pM, good selectivity, as well as good recovery rates of 106.2-113.5% when analyzing STX in real shellfish samples were obtained. This strategy could be referred to develop robust aptasensors for simple and highly sensitive detection of other small molecules and toxins.


Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Nanopartículas Metálicas , Catálise , Colorimetria , Ouro , Limite de Detecção , Saxitoxina
10.
Nat Commun ; 12(1): 2551, 2021 05 05.
Artigo em Inglês | MEDLINE | ID: mdl-33953173

RESUMO

Endogenous cardiac pacemaker function regulates the rate and rhythm of cardiac contraction. The mutation p.Lys23Glu in the cohesin protein Shugoshin-1 causes severe heart arrhythmias due to sinoatrial node dysfunction and a debilitating gastrointestinal motility disorder, collectively termed the Chronic Atrial and Intestinal Dysrhythmia Syndrome, linking Shugoshin-1 and pacemaker activity. Hyperpolarization-activated, cyclic nucleotide-gated cation channel 4 (HCN4) is the predominant pacemaker ion-channel in the adult heart and carries the majority of the "funny" current, which strongly contributes to diastolic depolarization in pacemaker cells. Here, we study the mechanism by which Shugoshin-1 affects cardiac pacing activity with two cell models: neonatal rat ventricular myocytes and Chronic Atrial and Intestinal Dysrhythmia Syndrome patient-specific human induced pluripotent stem cell derived cardiomyocytes. We find that Shugoshin-1 interacts directly with HCN4 to promote and stabilize cardiac pacing. This interaction enhances funny-current by optimizing HCN4 cell-surface expression and function. The clinical p.Lys23Glu mutation leads to an impairment in the interaction between Shugoshin-1 and HCN4, along with depressed funny-current and dysrhythmic activity in induced pluripotent stem cell derived cardiomyocytes derived from Chronic Atrial and Intestinal Dysrhythmia Syndrome patients. Our work reveals a critical non-canonical, cohesin-independent role for Shugoshin-1 in maintaining cardiac automaticity and identifies potential therapeutic avenues for cardiac pacemaking disorders, in particular Chronic Atrial and Intestinal Dysrhythmia Syndrome.


Assuntos
Proteínas de Ciclo Celular/metabolismo , Proteínas Cromossômicas não Histona/metabolismo , Canais Disparados por Nucleotídeos Cíclicos Ativados por Hiperpolarização/metabolismo , Proteínas Musculares/metabolismo , Canais de Potássio/metabolismo , Animais , Arritmias Cardíacas , Proteínas de Ciclo Celular/genética , Linhagem Celular , Sobrevivência Celular , Proteínas Cromossômicas não Histona/genética , Técnicas de Silenciamento de Genes , Canais Disparados por Nucleotídeos Cíclicos Ativados por Hiperpolarização/genética , Células-Tronco Pluripotentes Induzidas/metabolismo , Transporte de Íons/fisiologia , Proteínas Musculares/genética , Contração Miocárdica , Miócitos Cardíacos/metabolismo , Marca-Passo Artificial , Canais de Potássio/genética , Ratos
11.
Int J Endocrinol ; 2021: 6622129, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33747078

RESUMO

Objective: Asprosin, a new adipocytokine, has reportedly been associated with glucose release, dyslipidemia, and insulin resistance (IR). However, the relationship of asprosin with metabolic syndrome (MetS) remains unknown. This study aimed to investigate serum asprosin levels in MetS as well as their association with various metabolic parameters in humans. Methods: A total of 131 consecutive patients with MetS, and 162 age-matched, healthy subjects were recruited for this study. Serum asprosin concentrations were determined using the enzyme-linked immunosorbent assay. Lipid profile, glucose, insulin, and inflammatory markers were also measured. Results: Serum asprosin levels were higher in subjects with MetS (23.52 [16.70, 32.05] ng/mL) than in controls (16.70 [12.87, 22.38] ng/mL; P < 0.01), and they showed an increasing trend with increasing numbers of metabolic components (P for trend < 0.01). In all studied subjects, serum asprosin levels were positively correlated with body mass index, waist circumference, triglycerides, fasting plasma glucose, 2-hour plasma glucose, fasting insulin, homeostatic model assessment of insulin resistance (HOMA-IR) index, interleukin-6, and monocyte chemoattractant protein-1 and negatively correlated with high-density lipoprotein cholesterol (P < 0.05). In multiple linear regression, asprosin was independently and positively correlated with triglyceride and HOMA-IR (P < 0.05). Binary logistic regression revealed that asprosin was independently and positively correlated with the occurrence of MetS and IR, even after controlling for anthropometric variables, lipid profiles, and inflammatory markers. Conclusion: Asprosin is a potential metabolic-related adipokine and may be related to IR and MetS. This trial was registered with ChiCTR, ChiCTR1800018347.

12.
Circ Res ; 128(5): 619-635, 2021 03 05.
Artigo em Inglês | MEDLINE | ID: mdl-33375812

RESUMO

RATIONALE: The mechanisms underlying atrial fibrillation (AF), the most common clinical arrhythmia, are poorly understood. Nucleoplasmic Ca2+ regulates gene expression, but the nature and significance of nuclear Ca2+-changes in AF are largely unknown. OBJECTIVE: To elucidate mechanisms by which AF alters atrial-cardiomyocyte nuclear Ca2+ ([Ca2+]Nuc) and CaMKII (Ca2+/calmodulin-dependent protein kinase-II)-related signaling. METHODS AND RESULTS: Atrial cardiomyocytes were isolated from control and AF dogs (kept in AF by atrial tachypacing [600 bpm × 1 week]). [Ca2+]Nuc and cytosolic [Ca2+] ([Ca2+]Cyto) were recorded via confocal microscopy. Diastolic [Ca2+]Nuc was greater than [Ca2+]Cyto under control conditions, while resting [Ca2+]Nuc was similar to [Ca2+]Cyto; both diastolic and resting [Ca2+]Nuc increased with AF. IP3R (Inositol-trisphosphate receptor) stimulation produced larger [Ca2+]Nuc increases in AF versus control cardiomyocytes, and IP3R-blockade suppressed the AF-related [Ca2+]Nuc differences. AF upregulated nuclear protein expression of IP3R1 (IP3R-type 1) and of phosphorylated CaMKII (immunohistochemistry and immunoblot) while decreasing the nuclear/cytosolic expression ratio for HDAC4 (histone deacetylase type-4). Isolated atrial cardiomyocytes tachypaced at 3 Hz for 24 hours mimicked AF-type [Ca2+]Nuc changes and L-type calcium current decreases versus 1-Hz-paced cardiomyocytes; these changes were prevented by IP3R knockdown with short-interfering RNA directed against IP3R1. Nuclear/cytosolic HDAC4 expression ratio was decreased by 3-Hz pacing, while nuclear CaMKII phosphorylation was increased. Either CaMKII-inhibition (by autocamtide-2-related peptide) or IP3R-knockdown prevented the CaMKII-hyperphosphorylation and nuclear-to-cytosolic HDAC4 shift caused by 3-Hz pacing. In human atrial cardiomyocytes from AF patients, nuclear IP3R1-expression was significantly increased, with decreased nuclear/nonnuclear HDAC4 ratio. MicroRNA-26a was predicted to target ITPR1 (confirmed by luciferase assay) and was downregulated in AF atrial cardiomyocytes; microRNA-26a silencing reproduced AF-induced IP3R1 upregulation and nuclear diastolic Ca2+-loading. CONCLUSIONS: AF increases atrial-cardiomyocyte nucleoplasmic [Ca2+] by IP3R1-upregulation involving miR-26a, leading to enhanced IP3R1-CaMKII-HDAC4 signaling and L-type calcium current downregulation. Graphic Abstract: A graphic abstract is available for this article.


Assuntos
Fibrilação Atrial/metabolismo , Cálcio/metabolismo , Receptores de Inositol 1,4,5-Trifosfato/metabolismo , Miócitos Cardíacos/metabolismo , Potenciais de Ação , Animais , Fibrilação Atrial/fisiopatologia , Canais de Cálcio Tipo L/metabolismo , Sinalização do Cálcio , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Núcleo Celular/metabolismo , Células Cultivadas , Cães , Histona Desacetilases/metabolismo , Humanos , Receptores de Inositol 1,4,5-Trifosfato/genética , MicroRNAs/genética , MicroRNAs/metabolismo , Miócitos Cardíacos/fisiologia
13.
J Ethnopharmacol ; 269: 113705, 2021 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-33346025

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Hard antler extract (HAE) is a traditional Chinese medicine and has potent antitumor, antioxidative, anti-inflammatory, and immunomodulatory activities. Previous studies have demonstrated that HAE can inhibit human prostate cancer metastasis and murine breast cancer proliferation. However, the effect of HAE on human breast cancer cells has not been clarified. AIM OF THE STUDY: To investigate the effects and underlying mechanism of HAE on self-renewal of stem-like cells and spontaneous and transforming growth factor (TGF)-ß1-enhanced wound healing, invasion and epithelial-mesenchymal transition (EMT) in breast cancer cells. METHODS: HAE was prepared from sika deer by sequential enzymatic digestions and the active compounds were determined by HPLC. The effects of HAE on the viability, mammosphere formation, wound healing and invasion of MDA-MB-231 and SK-BR3 cells were determined. The impact of HAE treatment on spontaneous and TGF-ß1-promoted EMT and the nuclear factor (NF)-κB signaling in breast cancer cells was examined by quantitative RT-PCR and western blotting. RESULTS: Treatment with HAE at varying concentrations did not change the viability of breast cancer cells. However, HAE at 0.25 or 0.5 mg/mL significantly reduced the number and size of formed mammospheres, and inhibited spontaneous and TGF-ß1-enhanced wound healing, invasion and EMT in MDA-MB-231 and SK-BR3 cells in a dose-dependent manner. TGF-ß1 treatment significantly decreased IκBα expression and increased NF-kBp65 phosphorylation in breast cancer cells, indicating that TGF-ß1 enhanced NF-κB signaling. In contrast, HAE treatment attenuated the spontaneous and TGF-ß1-enhanced NF-κB signaling in breast cancer cells. CONCLUSION: Our data indicated that HAE inhibited the self-renewal of stem-like cells and spontaneous and TGF-ß1-enhanced wound healing, invasion and EMT in breast cancer cells by attenuating the NF-κB signaling in vitro.


Assuntos
Chifres de Veado/química , Neoplasias da Mama/metabolismo , Transição Epitelial-Mesenquimal/efeitos dos fármacos , Subunidade p50 de NF-kappa B/antagonistas & inibidores , Extratos de Tecidos/química , Extratos de Tecidos/farmacologia , Neoplasias de Mama Triplo Negativas/metabolismo , Animais , Chifres de Veado/metabolismo , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Cervos , Etnopsicologia , Feminino , Humanos , Células-Tronco Neoplásicas/efeitos dos fármacos , Receptor ErbB-2/metabolismo , Transdução de Sinais/efeitos dos fármacos , Esferoides Celulares/efeitos dos fármacos , Esferoides Celulares/patologia , Extratos de Tecidos/isolamento & purificação , Fator de Crescimento Transformador beta1/toxicidade , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Neoplasias de Mama Triplo Negativas/patologia , Cicatrização/efeitos dos fármacos
14.
Cardiovasc Res ; 117(2): 462-471, 2021 01 21.
Artigo em Inglês | MEDLINE | ID: mdl-31977017

RESUMO

AIMS: No studies have assessed the specific contributions of atrial fibrillation (AF)-related atrial vs. associated ventricular arrhythmia to remodelling. This study assessed the roles of atrial arrhythmia vs. high ventricular rate in AF-associated remodelling. METHODS AND RESULTS: Four primary dog-groups (12/group) were subjected to 3-week pacing: 600-b.p.m. atrial tachypacing maintaining AF [AF w/o- atrioventricular block (AVB)]; atrial tachypacing with atrioventricular-node ablation (AF+AVB) and ventricular-demand pacing (80 b.p.m.); 160-b.p.m. ventricular-tachypacing (V160) reproducing the response rate during AF; and sinus rhythm with AVB/ventricular-pacing at 80-b.p.m. (control group). At terminal study, left-atrial (LA) effective refractory period (ERP) was reduced equally in both AF groups (w/o-AVB and AF+AVB). AF-inducibility was increased strongly in AF groups (w/o-AVB and AF+AVB) and modestly in V160. AF duration was significantly increased in AF w/o-AVB but not in AF+AVB or V160. Conduction velocity was decreased in AF w/o-AVB, to a greater extent than in AF+AVB and V160. Atrial fibrous-tissue content was increased in AF w/o-AVB, AF+AVB and V160, with collagen-gene up-regulation only in AF w/o-AVB. Connexin43 gene expression was reduced only in AF w/o-AVB. An additional group of 240-b.p.m. ventricular tachypacing dogs (VTP240; to induce heart failure) was studied: vs. other tachypaced groups, VTP240 caused greater fibrosis, but no change in LA-ERP or AF-inducibility. VTP240 also increased AF duration, strongly decreased left ventricular ejection fraction, and was the only group with LA natriuretic-peptide activation. CONCLUSION: The atrial tachyarrhythmia and rapid ventricular response during AF produce distinct atrial remodelling; both contribute to the arrhythmogenic substrate, providing new insights into AF-related remodelling and novel considerations for ventricular rate-control.

15.
Physiol Rep ; 8(22): e14631, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-33242364

RESUMO

Fewer females develop AADs (ascending aortic aneurysms and dissections) and the reasons for this protection remain poorly understood. The present study seeks to develop a mouse model that may be utilized to address this sexual dimorphism. Adult normolipidemic mice were challenged with BAPN (ß-aminopropionitrile), AngII (angiotensin II), or BAPN + AngII. An initial protocol optimization found that 0.2% BAPN in drinking water plus AngII-infusion at 1,000 ng kg-1  min-1 produced favorable rates of AAD rupture (~50%) and dilation (~40%) in 28 days. Using these dosages, further experiments revealed that BAPN is toxic to naïve mature aortas and it acted synergistically with AngII to promote aortic tears and dissections. BAPN + AngII provoked early infiltration of myeloid cells and subsequent recruitment of lymphoid cells to the aortic wall. AADs established with BAPN + AngII, but not AngII alone, continued to expand after the cessation of AngII-infusion. This indefinite growth precipitated a 61% increase in the AAD diameter in 56 days. More importantly, with the optimized protocol, significant differences in AAD dilation (p = .012) and medial degeneration (p = .036) were detected between male and female mice. Treatment of ovariectomized mice with estradiol protected AAD formation (p = .014). In summary, this study developed a powerful mouse AAD model that can be used to study the sexual dimorphism in AAD formation.


Assuntos
Aneurisma Dissecante/patologia , Aneurisma Aórtico/patologia , Modelos Animais de Doenças , Estradiol/uso terapêutico , Estrogênios/uso terapêutico , Aminopropionitrilo/administração & dosagem , Aminopropionitrilo/toxicidade , Aneurisma Dissecante/etiologia , Aneurisma Dissecante/prevenção & controle , Angiotensina II/administração & dosagem , Angiotensina II/toxicidade , Animais , Aorta/efeitos dos fármacos , Aorta/patologia , Aneurisma Aórtico/etiologia , Aneurisma Aórtico/prevenção & controle , Feminino , Linfócitos/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Células Mieloides/metabolismo
16.
J Am Coll Cardiol ; 76(4): 374-388, 2020 07 28.
Artigo em Inglês | MEDLINE | ID: mdl-32703507

RESUMO

BACKGROUND: Atrial flutter (AFL) and atrial fibrillation (AF) are associated with AF-promoting atrial remodeling, but no experimental studies have addressed remodeling with sustained AFL. OBJECTIVES: This study aimed to define the atrial remodeling caused by sustained atrial flutter (AFL) and/or atrial fibrillation (AF). METHODS: Intercaval radiofrequency lesions created a substrate for sustained isthmus-dependent AFL, confirmed by endocavity mapping. Four groups (6 dogs per group) were followed for 3 weeks: sustained AFL; sustained AF (600 beats/min atrial tachypacing); AF superimposed on an AFL substrate (AF+AFLs); sinus rhythm (SR) with an AFL substrate (SR+AFLs; control group). All dogs had atrioventricular-node ablation and ventricular pacemakers at 80 beats/min to control ventricular rate. RESULTS: Monitoring confirmed spontaneous AFL maintenance >99% of the time in dogs with AFL. At terminal open-chest study, left-atrial (LA) effective refractory period was reduced similarly with AFL, AF+AFLs and AF, while AF vulnerability to extrastimuli increased in parallel. Induced AF duration increased significantly in AF+AFLs and AF, but not AFL. Dogs with AF+AFLs had shorter cycle lengths and substantial irregularity versus dogs with AFL. LA volume increased in AF+AFLs and AF, but not dogs with AFL, versus SR+AFLs. Optical mapping showed significant conduction slowing in AF+AFLs and AF but not AFL, paralleling atrial fibrosis and collagen-gene upregulation. Left-ventricular function did not change in any group. Transcriptomic analysis revealed substantial dysregulation of inflammatory and extracellular matrix-signaling pathways with AF and AF+ALs but not AFL. CONCLUSIONS: Sustained AFL causes atrial repolarization changes like those in AF but, unlike AF or AF+AFLs, does not induce structural remodeling. These results provide novel insights into AFL-induced remodeling and suggest that early intervention may be important to prevent irreversible fibrosis when AF intervenes in a patient with AFL.


Assuntos
Fibrilação Atrial , Flutter Atrial , Remodelamento Atrial , Átrios do Coração , Animais , Fibrilação Atrial/complicações , Fibrilação Atrial/patologia , Fibrilação Atrial/fisiopatologia , Flutter Atrial/complicações , Flutter Atrial/patologia , Flutter Atrial/fisiopatologia , Ablação por Cateter/métodos , Cães , Eletrocardiografia/métodos , Fibrose/etiologia , Fibrose/patologia , Fibrose/prevenção & controle , Átrios do Coração/patologia , Átrios do Coração/fisiopatologia
18.
JCI Insight ; 5(8)2020 04 07.
Artigo em Inglês | MEDLINE | ID: mdl-32255765

RESUMO

Atrial fibrillation (AF) alters atrial cardiomyocyte (ACM) Ca2+ handling, promoting ectopic beat formation. We examined the effects of AF-associated remodeling on Ca2+-related action potential dynamics and consequences for AF susceptibility. AF was maintained electrically in dogs by right atrial (RA) tachypacing. ACMs isolated from AF dogs showed increased Ca2+ release refractoriness, spontaneous Ca2+ spark frequency, and cycle length (CL) threshold for Ca2+ and action potential duration (APD) alternans versus controls. AF increased the in situ CL threshold for Ca2+/APD alternans and spatial dispersion in Ca2+ release recovery kinetics, leading to spatially discordant alternans associated with reentrant rotor formation and susceptibility to AF induction/maintenance. The clinically available agent dantrolene reduced Ca2+ leak and CL threshold for Ca2+/APD alternans in ACMs and AF dog right atrium, while suppressing AF susceptibility; caffeine increased Ca2+ leak and CL threshold for Ca2+/APD alternans in control dog ACMs and RA tissues. In vivo, the atrial repolarization alternans CL threshold was increased in AF versus control, as was AF vulnerability. Intravenous dantrolene restored repolarization alternans threshold and reduced AF vulnerability. Immunoblots showed reduced expression of total and phosphorylated ryanodine receptors and calsequestrin in AF and unchanged phospholamban/SERCA expression. Thus, along with promoting spontaneous ectopy, AF-induced Ca2+ handling abnormalities favor AF by enhancing vulnerability to repolarization alternans, promoting initiation and maintenance of reentrant activity; dantrolene provides a lead molecule to target this mechanism.


Assuntos
Potenciais de Ação , Fibrilação Atrial/metabolismo , Sinalização do Cálcio , Cálcio/metabolismo , Miócitos Cardíacos/metabolismo , Animais , Fibrilação Atrial/fisiopatologia , Cães , Átrios do Coração/metabolismo , Átrios do Coração/fisiopatologia , Masculino
19.
J Endocrinol ; 245(1): 93-100, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32027602

RESUMO

Remodeling of energy-storing white fat into energy-consuming beige fat has led to a promising new approach to alleviate adiposity. Several studies have shown adipokines can induce white adipose tissue (WAT) beiging through autocrine or paracrine actions. Betatrophin, a novel adipokine, has been linked to energy expenditure and lipolysis but not clearly clarified. Here, we using high-fat diet-induced obesity to determine how betatrophin modulate beiging and adiposity. We found that betatrophin-knockdown mice displayed less white fat mass and decreased plasma TG and NEFA levels. Consistently, inhibition of betatrophin leads to the phenotype change of adipocytes characterized by increased mitochondria contents, beige adipocytes and mitochondria biogenesis-specific markers both in vivo and in vitro. Of note, blocking AMP-activated protein kinase (AMPK) signaling pathway is able to abolish enhanced beige-like characteristics in betatrophin-knockdown adipocytes. Collectively, downregulation of betatrophin induces beiging in white adipocytes through activation of AMPK signaling pathway. These processes suggest betatrophin as a latent therapeutic target for obesity.


Assuntos
Adipócitos Bege/metabolismo , Adipócitos Brancos/metabolismo , Tecido Adiposo Branco/metabolismo , Proteínas Semelhantes a Angiopoietina/metabolismo , Mitocôndrias/metabolismo , Células 3T3-L1 , Proteínas Quinases Ativadas por AMP/metabolismo , Adipócitos Bege/citologia , Adipócitos Brancos/citologia , Tecido Adiposo Branco/citologia , Adiposidade/genética , Proteínas Semelhantes a Angiopoietina/genética , Animais , Dieta Hiperlipídica/efeitos adversos , Metabolismo Energético/genética , Ácidos Graxos não Esterificados/sangue , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Obesidade/etiologia , Obesidade/genética , Obesidade/metabolismo , Interferência de RNA , Transdução de Sinais , Triglicerídeos/sangue
20.
J Biomol Struct Dyn ; 38(7): 2068-2079, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31204596

RESUMO

S100A4 is a multiple-function protein highly expressed in tumor or stem cells. We found S100A4 was a novel protein partner for heat shock protein 47 (HSP47) in deer antlerogenic periosteum cells (AP cells), indicating that S100A4 could bind with HSP47. S100A4 had both calcium-dependent and calcium-independent patterns (labeled as SCd and SCi, respectively) to execute different biological activities. Homology models of HSP47, SCd and SCi were constructed. HSP47:collagen model, HSP47:collagen I-V, HSP47:SCd and HSP47:SCi complexes were built using ZDOCK software. Together with free SCd and SCi, 200 ns molecular dynamic (MD) simulations were performed to analyze binding free energies and SCi/SCd conformational changes. The energetic results showed that SCi had the strongest affinity to HSP47, and followed by collagens. SCd had little interaction with HSP47. Decomposition energy results showed that collagen model interacted with HSP47 mainly though neutral amino acids. When SCi bound with HSP47, the majority of mediated amino acids were charged. These results indicated that SCi could compete with collagen on the binding site of HSP47. Root mean square fluctuation (RMSF) values and cross-correlation matrices of principal component analysis (PCA) were calculated to evaluate the SCi/SCd structural variation during MD simulation. Both HSP47 and Ca2+ could stabilize the conformation of SCi/SCd. The loops interacting with Ca2+s and linking the two EF-hand motifs were impacted particularly. The relative moving directions of α-helices in EF-hands were distinct by the binding effect of HSP47 and Ca2+. We found that SCi may regulate the differentiation of AP cells by disturbing the interaction between HSP47 and collagen. Communicated by Ramaswamy H. Sarma.


Assuntos
Chifres de Veado , Cálcio/química , Proteínas de Choque Térmico HSP47/química , Proteína A4 de Ligação a Cálcio da Família S100/química , Células-Tronco , Animais , Chifres de Veado/citologia , Cervos
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