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1.
Environ Toxicol ; 36(4): 520-529, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33166055

RESUMO

Colorectal cancer stem cell (CSC) has been regarded to be the root of colorectal cancer progression. However, there is still no effective therapeutic method targeting colorectal CSC in clinical application. Here, we investigated the effects of dichloroacetate (DCA) on colorectal cancer cell stemness. We showed that DCA could reduce colorectal cancer cell stemness in a dose-dependent manner, which is evident by the decreased expression of stemness markers, tumor cell sphere-formation and cell migration ability. In addition, it was found that DCA trigerred the ferroptosis of colorectal CSC, which is characterized as the upregulation of iron concentration, lipid peroxides, and glutathione level, and decreased cell viability. Mechanistic studies demonstrated that DCA could sequester iron in lysosome and thus trigger ferroptosis, which is necessary for DCA-mediated attenuation on colorectal cancer cell stemness. Taken together, this work suggests that DCA might be a colorectal CSC-killer.


Assuntos
Neoplasias Colorretais/patologia , Ácido Dicloroacético/farmacologia , Ferroptose/efeitos dos fármacos , Ferro/metabolismo , Lisossomos/efeitos dos fármacos , Células-Tronco Neoplásicas/efeitos dos fármacos , Sequestrantes/farmacologia , Movimento Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Neoplasias Colorretais/metabolismo , Relação Dose-Resposta a Droga , Células HCT116 , Células HT29 , Humanos , Lisossomos/metabolismo , Células-Tronco Neoplásicas/metabolismo , Células-Tronco Neoplásicas/patologia
2.
J Dairy Sci ; 103(2): 1559-1565, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31785870

RESUMO

Aflatoxin is a potent carcinogen commonly found in animal feeds that can impair rumen fermentation at high concentrations; however, its effects at physiologically relevant concentrations are unknown. This study examined the effects of aflatoxin B1 (AFB1), with or without bentonite clay (CL) and Saccharomyces cerevisiae fermentation product (SCFP)-based sequestering agents on in vitro rumen fermentation and digestibility of a dairy cow TMR. Corn silage-based TMR (0.5 g, 17.3% crude protein and 1.67 Mcal/kg of net energy for lactation) was incubated in a rumen fluid-buffer inoculum (1:2 ratio; 50 mL) with the following treatments: (1) no additives (control); (2) control + 0.75 µg/L AFB1 (T); (3) T + 80 mg/L sodium bentonite clay (CL; Astra-Ben-20, Prince Agri Products Inc., Quincy, IL); or (4) CL + 14 mg/L SCFP (CL+SCFP; Diamond V, Cedar Rapids, IA). Ruminal fluid was collected 3 h after the morning feeding from 3 cannulated cows fed the same TMR, and rumen fluid from individual cows was used to prepare separate inocula. Each treatment was incubated in duplicate at 39°C for 0, 4, 8, 16, and 24 h in each of 3 runs. Adding T reduced total volatile fatty acid (VFA) concentration after 4 and 8 h and molar proportion of propionate after 4 and 24 h of incubation relative to control. Adding sequestering agents (CL and CL+SCFP) with T did not affect total VFA concentration after 4 or 8 h, but increased total VFA after 16 h and tended to increase molar proportion of propionate after 24 h compared with T. At 24 h, T had lower DM digestibility and higher NH3-N concentration compared with the control. Thus, AFB1, even at very low concentration (0.75 µg/L), had detrimental effects on rumen fermentation and subsequently DM digestibility of the TMR. Adding sequestering agents did not prevent negative effects of T on rumen fermentation within 8 h of incubation; however, sequestering agents were effective after 16 h of incubation.


Assuntos
Aflatoxina B1/toxicidade , Ração Animal , Bovinos , Venenos/toxicidade , Rúmen/efeitos dos fármacos , Aflatoxina B1/metabolismo , Ração Animal/análise , Animais , Bentonita/farmacologia , Dieta/veterinária , Feminino , Fermentação/efeitos dos fármacos , Lactação/fisiologia , Rúmen/metabolismo , Saccharomyces cerevisiae/metabolismo , Sequestrantes/farmacologia , Silagem/análise , Zea mays
3.
Int J Mol Sci ; 20(19)2019 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-31554226

RESUMO

Selenocompounds (SeCs) are well-known nutrients and promising candidates for cancer therapy; however, treatment efficacy is very heterogeneous and the mechanism of action is not fully understood. Several SeCs have been reported to have albumin-binding ability, which is an important factor in determining the treatment efficacy of drugs. In the present investigation, we hypothesized that extracellular albumin might orchestrate SeCs efficacy. Four SeCs representing distinct categories were selected to investigate their cytotoxicity, cellular uptake, and species transformation. Concomitant treatment of albumin greatly decreased cytotoxicity and cellular uptake of SeCs. Using both X-ray absorption spectroscopy and hyphenated mass spectrometry, we confirmed the formation of macromolecular conjugates between SeCs and albumin. Although the conjugate was still internalized, possibly via albumin scavenger receptors expressed on the cell surface, the uptake was strongly inhibited by excess albumin. In summary, the present investigation established the importance of extracellular albumin binding in determining SeCs cytotoxicity. Due to the fact that albumin content is higher in humans and animals than in cell cultures, and varies among many patient categories, our results are believed to have high translational impact and clinical implications.


Assuntos
Albuminas/química , Sequestrantes/química , Sequestrantes/farmacologia , Albuminas/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Estrutura Molecular , Espécies Reativas de Oxigênio/metabolismo , Análise Espectral
4.
Toxins (Basel) ; 11(10)2019 09 26.
Artigo em Inglês | MEDLINE | ID: mdl-31561495

RESUMO

In warm agricultural areas across the globe, maize, groundnut, and other crops become frequently contaminated with aflatoxins produced primarily by the fungus Aspergillus flavus. Crop contamination with those highly toxic and carcinogenic compounds impacts both human and animal health, as well as the income of farmers and trade. In Nigeria, poultry productivity is hindered by high prevalence of aflatoxins in feeds. A practical solution to decrease crop aflatoxin content is to use aflatoxin biocontrol products based on non-toxin-producing strains of A. flavus. The biocontrol product Aflasafe® was registered in 2014 for use in maize and groundnut grown in Nigeria. Its use allows the production of aflatoxin-safe maize and groundnut. A portion of the maize treated with Aflasafe in Nigeria is being used to manufacture feeds used by the poultry industry, and productivity is improving. One of the conditions to register Aflasafe with the national regulator was to demonstrate both the safety of Aflasafe-treated maize to avian species and the impact of Aflasafe as a public good. Results presented here demonstrate that the use of maize colonized by an atoxigenic strain of Aflasafe resulted in superior (p < 0.05) broiler performance in all evaluated parameters in comparison to broilers fed with toxigenic maize. Use of an aflatoxin-sequestering agent (ASA) was not sufficient to counteract the harmful effects of aflatoxins. Both the safety and public good value of Aflasafe were demonstrated during our study. In Nigeria, the availability of aflatoxin-safe crops as a result of using Aflasafe allows poultry producers to improve their productivity, their income, and the health of consumers of poultry products.


Assuntos
Aflatoxinas/metabolismo , Aspergillus flavus/patogenicidade , Agentes de Controle Biológico/farmacologia , Galinhas , Produtos Agrícolas/microbiologia , Sequestrantes/farmacologia , Zea mays/microbiologia , Aflatoxinas/toxicidade , Animais , Contaminação de Alimentos/análise
5.
J Am Coll Cardiol ; 70(14): 1785-1822, 2017 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-28886926

RESUMO

In 2016, the American College of Cardiology published the first expert consensus decision pathway (ECDP) on the role of non-statin therapies for low-density lipoprotein (LDL)-cholesterol lowering in the management of atherosclerotic cardiovascular disease (ASCVD) risk. Since the publication of that document, additional evidence and perspectives have emerged from randomized clinical trials and other sources, particularly considering the longer-term efficacy and safety of proprotein convertase subtilisin/kexin 9 (PCSK9) inhibitors in secondary prevention of ASCVD. Most notably, the FOURIER (Further Cardiovascular Outcomes Research with PCSK9 Inhibition in Subjects with Elevated Risk) trial and SPIRE-1 and -2 (Studies of PCSK9 Inhibition and the Reduction of Vascular Events), assessing evolocumab and bococizumab, respectively, have published final results of cardiovascular outcomes trials in patients with clinical ASCVD and in a smaller number of high-risk primary prevention patients. In addition, further evidence on the types of patients most likely to benefit from the use of ezetimibe in addition to statin therapy after acute coronary syndrome has been published. Based on results from these important analyses, the ECDP writing committee judged that it would be desirable to provide a focused update to help guide clinicians more clearly on decision making regarding the use of ezetimibe and PCSK9 inhibitors in patients with clinical ASCVD with or without comorbidities. In the following summary table, changes from the 2016 ECDP to the 2017 ECDP Focused Update are highlighted, and a brief rationale is provided. The content of the full document has been changed accordingly, with more extensive and detailed guidance regarding decision making provided both in the text and in the updated algorithms. Revised recommendations are provided for patients with clinical ASCVD with or without comorbidities on statin therapy for secondary prevention. The ECDP writing committee judged that these new data did not warrant changes to the decision pathways and algorithms regarding the use of ezetimibe or PCSK9 inhibitors in primary prevention patients with LDL-C <190 mg/dL with or without diabetes mellitus or patients without ASCVD and LDL-C ≥190 mg/dL not due to secondary causes. Based on feedback and further deliberation, the ECDP writing committee down-graded recommendations regarding bile acid sequestrant use, recommending bile acid sequestrants only as optional secondary agents for consideration in patients intolerant to ezetimibe. For clarification, the writing committee has also included new information on diagnostic categories of heterozygous and homozygous familial hypercholesterolemia, based on clinical criteria with and without genetic testing. Other changes to the original document were kept to a minimum to provide consistent guidance to clinicians, unless there was a compelling reason or new evidence, in which case justification is provided.


Assuntos
Anticolesterolemiantes/farmacologia , Cardiologia/métodos , Doença da Artéria Coronariana/prevenção & controle , Ezetimiba/farmacologia , Hipercolesterolemia/tratamento farmacológico , Conduta do Tratamento Medicamentoso/organização & administração , Quimioprevenção/métodos , LDL-Colesterol/análise , Consenso , Inibidores Enzimáticos/farmacologia , Humanos , Hipercolesterolemia/diagnóstico , Sequestrantes/farmacologia , Estados Unidos
6.
Ren Fail ; 37(1): 7-15, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25350834

RESUMO

AIM: To assess the effects and safety of iron-based phosphate binders in adult patients receiving dialysis. METHODS: We electronically searched MEDLINE, EMBASE, CENTRAL, and CBM for randomized controlled trials about iron-based phosphate binders in adult dialysis patients. Study quality was assessed using the criteria outlined in the Cochrane Handbook for Systematic Reviews of intervention. Meta-analysis was conducted by RevMan 5.3. RESULTS: Eight studies with 2018 participants were eligible for our meta-analysis. Iron-based phosphate binders were superior to placebo (MD = -2.43 mg/dL, 95% CI: -3.18 to -1.68, p < 0.00001) and as efficient as sevelamer (MD = 0.04 mg/dL, 95% CI: -0.29 to 0.36, p = 0.83) in reducing serum phosphorus in dialysis patients. No significant differences were found in all adverse events (OR = 1.30, 95% CI: 0.77 to 2.20, p = 0.32) between iron-based phosphate binders and placebo. Iron-based phosphate binders were associated with significant higher serum iron (MD = 9.39 ng/mL, 95% CI 1.48 to 17.30, p = 0.02), higher serum transferring saturation (MD = 6.29%, 95% CI 2.72 to 9.87, p = 0.0006) and lower serum total iron binding capacity (MD = -23.13 µg/dL, 95% CI -35.69 to -10.58, p = 0.0003) in comparison to placebo. CONCLUSION: Iron-based phosphate binders are as effective as sevelamer and well tolerated for hyperphosphatemia in dialysis patients. Iron-based phosphate binders appear to have a beneficial effect on renal anemia in patients receiving dialysis. Therefore, iron-based phosphate binders may represent a new treatment option for dialysis patients.


Assuntos
Hiperfosfatemia , Fosfatos/metabolismo , Diálise Renal/efeitos adversos , Sequestrantes/farmacologia , Humanos , Hiperfosfatemia/tratamento farmacológico , Hiperfosfatemia/etiologia , Hiperfosfatemia/metabolismo , Ferro/farmacologia , Poliaminas/farmacologia , Ensaios Clínicos Controlados Aleatórios como Assunto , Sevelamer
8.
J Periodontol ; 84(12): 1858-68, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23510146

RESUMO

BACKGROUND: The use of antimicrobial peptides (AMPs) as therapeutic agents for periodontal infections has great advantages, such as broad spectrum of action, low toxicity, and limited bacterial resistance. However, their practical use is limited because of the large amount of peptide required to exercise the microbicidal function. METHODS: LyeTxI, LL37f, and KR12 cationic peptides were prepared with ß-cyclodextrin (ßCD) at 1:1 molar ratios. The susceptibility of Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, and Fusobacterium nucleatum were assessed in anaerobic conditions. Cytotoxicity assays were performed using osteoblast and Caco-2 epithelial cells, and hemolytic activity was assessed on rabbit erythrocytes at an absorbance of 414 nm. Parameters of surface roughness and electrical charge were established by atomic force microscopy and zeta (ζ) potential, respectively. RESULTS: AMP/ßCDs drastically decreased the peptide concentration required for activity against the bacteria tested. Moreover, AMPs associated with ßCD were able to modify cell-surface parameters, such as roughness and ζ potential. On the other hand, AMP/ßCD did not alter the degree of hemolysis induced by the pure AMPs. The effective concentration at half-maximum values of the peptides and compounds on osteoblasts were greater than the concentrations required to achieve inhibition of bacterial growth in all the species tested. AMP/ßCDs inhibited the proliferation of Caco-2 epithelial cells in a more efficient manner than AMPs alone. CONCLUSION: AMP/ßCD compounds more effectively inhibit periodontopathogenic bacteria than AMPs alone, with the additional ability of inhibiting the proliferation of epithelial cells at concentrations that are non-cytotoxic for osteoblasts and erythrocytes.


Assuntos
Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Antimitóticos/farmacologia , Sequestrantes/farmacologia , beta-Ciclodextrinas/farmacologia , Aggregatibacter actinomycetemcomitans/efeitos dos fármacos , Animais , Antibacterianos/administração & dosagem , Peptídeos Catiônicos Antimicrobianos/administração & dosagem , Antimitóticos/administração & dosagem , Células CACO-2/efeitos dos fármacos , Catelicidinas/farmacologia , Proliferação de Células/efeitos dos fármacos , Eletroquímica , Células Epiteliais/efeitos dos fármacos , Eritrócitos/efeitos dos fármacos , Fusobacterium nucleatum/efeitos dos fármacos , Hemólise/efeitos dos fármacos , Humanos , Microscopia de Força Atômica , Osteoblastos/efeitos dos fármacos , Fragmentos de Peptídeos/farmacologia , Porphyromonas gingivalis/efeitos dos fármacos , Coelhos , Sequestrantes/administração & dosagem , beta-Ciclodextrinas/administração & dosagem
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