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1.
Int. j. med. surg. sci. (Print) ; 9(2): 1-10, June 2022. ilus
Artigo em Espanhol | LILACS | ID: biblio-1512565

RESUMO

The receptor for advanced glycation end products (RAGE) is implicated in the pathogenesis of several chronic diseases including diabetes. The interaction between RAGE and advanced glycation end products (AGEs) promotes gene expression, enhances the release of proinflammatory molecules and causes the generation of oxidative stress in numerous cell types. The aim of this investigation was to evaluate the effect of enalapril and losartan on RAGE expression in abdominal aortic endothelium of rats with experimentally induced diabetes. Male Sprague-Dawley rats, weighing approximately 150 - 200 g, were used. Diabetes was induced in 30 rats by intravenous administration of a single dose of 55 mg/kg body weight of streptozotocin (ETZ). The following groups were studied: control (n=10), diabetic (n=10), losartan-treated diabetic (n=10) and enalapril-treated diabetic (n=10) rats. RAGE expression in aortic endothelium was determined by indirect immunofluorescence. A significant increase in RAGE expression was observed in diabetic animals versus controls (p<0.001), there was a decrease in RAGE expression, in animals treated with losartan versus controls (p<0.01) and in those treated with enalapril (p<0.05) versus control and versus diabetes + vehicle. In conclusion, in the experimental model of ETZ-induced diabetes, there is an increase in RAGE expression at the level of the abdominal aortic endothelium, which can be reversed by treatment with losartan and/or enalapril, two drugs that block the renin-angiotensin system, suggesting its involvement in the molecular events related to vascular damage during diabetes.


El receptor para productos finales de glicación avanzada (RAGE) está implicado en la patogénesis de varias enfermedades crónicas incluyendo la diabetes. La interacción entre RAGE y los productos finales de glicación avanzada (AGEs), promueve la expresión génica, potencia la liberación de moléculas proinflamatorias y provoca la generación de estrés oxidativo en numerosos tipos de células. El objetivo de esta investigación fue evaluar el efecto del enalapril y el losartán sobre la expresión de RAGE en el endotelio de la aorta abdominal de ratas con diabetes inducida experimentalmente. Se utilizaron ratas Sprague-Dawley machos, con un peso aproximado de entre 150 - 200 g. La diabetes se indujo en 30 ratas mediante la administración intravenosa de una sola dosis de 55 mg/Kg de peso corporal de estreptozotocina (ETZ). Se estudiaron los siguientes grupos: ratas control (n=10), diabéticas (n=10), diabéticas tratadas con losartán (n=10) y diabéticas tratadas con enalapril (n=10). La expresión de RAGE en el endotelio aórtico se determinó por inmunofluorescencia indirecta. Se observó un incremento significativo en la expresión de RAGE en los animales diabéticos versus los controles (p<0.001), hubo una disminución en la expresión de RAGE, en los animales tratados con losartán versus los controles (p<0.01) y en los tratados con enalapril (p<0.05) versus control y versus diabetes + vehículo. En conclusión, en el modelo experimental de diabetes inducida por ETZ, existe un incremento en la expresión de RAGE a nivel del endotelio de la aorta abdominal, la cual puede revertirse mediante el tratamiento con losartán y/o enalapril, dos fármacos bloqueadores del sistema renina-angiotensina, lo cual sugiere la participación del mismo en los acontecimientos moleculares relacionados con el daño vascular durante la diabetes.


Assuntos
Animais , Masculino , Ratos , Enalapril/farmacologia , Losartan/farmacologia , Diabetes Mellitus Experimental , Receptor para Produtos Finais de Glicação Avançada/efeitos dos fármacos , Aorta Abdominal , Inibidores da Enzima Conversora de Angiotensina/farmacologia , Imuno-Histoquímica , Ratos Sprague-Dawley , Bloqueadores do Receptor Tipo 1 de Angiotensina II/farmacologia , Endotélio , Receptor para Produtos Finais de Glicação Avançada/metabolismo
2.
Rev. Assoc. Med. Bras. (1992, Impr.) ; 67(9): 1251-1255, Sept. 2021. tab, graf
Artigo em Inglês | LILACS | ID: biblio-1351480

RESUMO

SUMMARY OBJECTIVE: To investigate the associations of high-mobility group box 1 and its specific receptor, receptor for advanced glycation end products with acute lung injury in patients with acute aortic dissection. METHODS: A total of 96 acute aortic dissection patients were divided into acute aortic dissection with acute lung injury group (38 cases) and acute aortic dissection without acute lung injury group (58 cases), according to partial pressure of oxygen/fraction of inspired oxygen. In addition, 44 healthy individuals were selected for the control group. The blood samples were taken. The serum high-mobility group box 1 and receptor for advanced glycation end products levels were detected by enzyme-linked immunosorbent assay, and the partial pressure of oxygen/fraction of inspired oxygen was measured. RESULTS: 24 h after admission, the high-mobility group box 1 and receptor for advanced glycation end products levels in acute aortic dissection with acute lung injury and acute aortic dissection without acute lung injury groups were significantly higher than those in the control group, respectively (p<0.05), and each index in acute aortic dissection with acute lung injury group was significantly higher than that in acute aortic dissection without acute lung injury group (p<0.05). At each time point within 96 h after admission, compared with acute aortic dissection without acute lung injury group, in acute aortic dissection with acute lung injury group, the high-mobility group box 1 and receptor for advanced glycation end products levels were increased, respectively, and the partial pressure of oxygen/fraction of inspired oxygen was decreased. The correlation analysis showed that, in acute aortic dissection patients, the high-mobility group box 1 and receptor for advanced glycation end products levels were negatively correlated with partial pressure of oxygen/fraction of inspired oxygen, respectively (p<0.05). CONCLUSIONS: The serum high-mobility group box 1 and receptor for advanced glycation end products levels may be associated with the occurrence of acute lung injury in acute aortic dissection patients. Monitoring the high-mobility group box 1 and receptor for advanced glycation end products levels can evaluate the risk of acute aortic dissection with acute lung injury.


Assuntos
Humanos , Proteína HMGB1/metabolismo , Lesão Pulmonar Aguda/etiologia , Receptor para Produtos Finais de Glicação Avançada/metabolismo , Dissecção Aórtica , Produtos Finais de Glicação Avançada
3.
Clinics ; 76: e2348, 2021. graf
Artigo em Inglês | LILACS | ID: biblio-1153978

RESUMO

OBJECTIVES: TTP488, an antagonist of the receptor for advanced glycation end-products, was evaluated as a potential treatment for patients with mild-to-moderate Alzheimer's disease (AD). However, the mechanism underlying the protective action of TTP488 against AD has not yet been fully explored. METHODS: Healthy male rats were exposed to aberrant amyloid β (Aβ) 1-42. Lipopolysaccharide (LPS) and the NOD-like receptor family pyrin domain containing 1 (NLRP1) overexpression lentivirus were injected to activate the NLRP1 inflammasome and exacerbate AD. TTP488 was administered to reverse AD injury. Finally, tofacitinib and fludarabine were used to inhibit the activity of Janus tyrosine kinase (JAK) and signal transducer and activator of transcription (STAT) to prove the relationship between the JAK/STAT signaling pathway and TTP488. RESULTS: LPS and NLRP1 overexpression significantly increased the NLRP1 levels, reduced neurological function, and aggravated neuronal damage, as demonstrated by the impact latency time of, time spent by, and length of the platform covered by, the mice in the Morris water maze assay, Nissl staining, and immunofluorescence staining in rats with AD. CONCLUSIONS: TTP488 administration successfully reduced AD injury and reversed the aforementioned processes. Additionally, tofacitinib and fludarabine administration could further reverse AD injury after the TTP488 intervention. These results suggest a new potential mechanism underlying the TTP488-mediated alleviation of AD injury.


Assuntos
Animais , Masculino , Camundongos , Ratos , Janus Quinases/metabolismo , Doença de Alzheimer/tratamento farmacológico , Tirosina , Transdutores , Transdução de Sinais , Peptídeos beta-Amiloides , Janus Quinase 2 , Receptor para Produtos Finais de Glicação Avançada , Imidazóis
4.
Rio de Janeiro; s.n; 2019. 71 p. ilus.
Tese em Português | LILACS | ID: biblio-1053042

RESUMO

A doença hepática gordurosa não alcoólica (DHGNA) afeta um terço da população adulta e é definida como o acúmulo de gordura no fígado de indivíduos que não consomem excessiva quantidade de álcool. No entanto, os mecanismos moleculares responsáveis pela progressão da doença ainda não foram completamente elucidados. Estudos anteriores do nosso grupo e outros autores demonstraram que o aumento nos níveis de produtos finais de glicação avançada (AGEs) e distúrbios da microcirculação estão presentes na DHGNA, mas nenhuma evidência direta da ligação entre os níveis de AGEs, estresse oxidativo, inflamação e alterações microcirculatórias hepáticas foi demonstrada. No presente trabalho, nós investigamos os efeitos protetores da piridoxamina (PirPM), um inibidor da formação de AGEs, nas complicações metabólicas e microcirculatórias na DHGNA. A DHGNA foi induzida por uma dieta hiperlipídica (HFD) em ratos Wistar durante 28 semanas. O tratamento com Pir (60 mg/Kg/dia, i.p.) foi administrado entre as semanas 20 e 28. Na microcirculação do fígado, o recrutamento de leucócitos e o número de células estreladas hepáticas (HSC´s) ativadas foram examinados por microscopia intravital.


A perfusão tecidual foi acessada por fluxometria utilizando o laser speckle. O estresse oxidativo e o marcador de inflamação foram avaliados pela dosagem de substâncias reativas ao ácido tiobarbitúrico (TBARs) e RT-PCR, respectivamente. Os AGEs no fígado foram avaliados por espectroscopia de fluorescência. Foi observado que a alteração no metabolismo da glicose e aumento do peso corporal, hepático e de tecido adiposo e esteatose no grupo DHGNA foi revertido pelo tratamento com Pir. Em relação aos parâmetros microcirculatórios hepáticos, ratos com DHGNA apresentaram aumento do rolamento e adesão de leucócitos, da ativação de HSCs e diminuição da perfusão tecidual. A Pir mostrou um efeito vasoprotetor nas alterações da microcirculação hepática induzidas pela DHGNA. O fígado de grupo DHGNA apresentou níveis elevados de peroxidação lipídica, que foram parcialmente revertidos pelo tratamento com Pir. Em conclusão, a Pir apresenta importante efeito vasoprotetor e antioxidante, além de modular os distúrbios metabólicos, sendo, portanto, um potencial tratamento para complicações microcirculatórias e metabólicas associadas à DHGNA. (AU)


Assuntos
Humanos , Animais , Piridoxamina , Síndrome Metabólica , Fígado Gorduroso , Hepatopatia Gordurosa não Alcoólica , Receptor para Produtos Finais de Glicação Avançada , Fígado
5.
Rev. Assoc. Med. Bras. (1992, Impr.) ; 63(11): 971-977, Nov. 2017. tab, graf
Artigo em Inglês | LILACS | ID: biblio-896309

RESUMO

Summary Objective: Interaction between advanced glycation end-products (AGEs) and receptor for AGEs (RAGE) in cells could affect both extracellular and intracellular structure and function, which plays a pivotal role in diabetic microvascular complications. The results from previous epidemiological studies on the association between RAGE gene -374T/A polymorphism and diabetic retinopathy (DR) risk were inconsistent. Thus, we conducted this meta-analysis to summarize the possible association between RAGE -374T/A polymorphism and DR risk. Method: We searched all relevant articles on the association between RAGE -374T/A polymorphism and DR risk from PubMed, Cochrane Library, ScienceDirect, Wanfang, VIP and Chinese National Knowledge Infrastructure (CNKI) web databases up to August 2016. Odds ratio (OR) with 95% confidence interval (CI) were calculated to assess those associations. All analyses were performed using the Review Manager software. Results: Nine case-control studies, including 1,705 DR cases and 2,236 controls were enrolled, and the results showed that the A allele of RAGE -374T/A polymorphism was significantly associated with increased DR risk in dominant model (TA/AA vs. TT: OR=1.22, 95CI 1.05-1.41, p=0.006) and heterozygote model (TA vs. TT: OR=1.26, 95CI 1.07-1.47, p=0.005). The subgroup analysis by ethnicity showed that significantly increased DR risk was found in both Asian and Caucasian populations. Conclusion: This meta-analysis reveals that the A allele of RAGE -374T/A polymorphism probably increase DR risk.


Assuntos
Humanos , Polimorfismo Genético , Diabetes Mellitus Tipo 2/genética , Retinopatia Diabética/genética , Fatores de Risco , Predisposição Genética para Doença , Diabetes Mellitus Tipo 2/complicações , Retinopatia Diabética/etiologia , Alelos , Receptor para Produtos Finais de Glicação Avançada , Genótipo
6.
Biol. Res ; 50: 23, 2017. graf
Artigo em Inglês | LILACS | ID: biblio-950874

RESUMO

BACKGROUND: Airway remodeling is a key feature of asthma, characterized by increased proliferation of airway smooth muscle cells (ASMCs). S100A8 is a calcium-binding protein with a potential to regulate cell proliferation. Here, the effect of exogenous S100A8 protein on the proliferation of ASMCs induced by platelet-derived growth factor (PDGF) and the underlying molecular mechanism was investigated. METHODS: Rat ASMCs were cultured with or without a neutralizing antibody to the receptor for advanced glycation end-products (RAGE), a potential receptor for S100A8 protein. Purified recombinant rat S100A8 protein was then added into the cultured cells, and the proliferation of ASMCs induced by PDGF was detected by colorimetric-based WST-8 assay and ampedance-based xCELLigence proliferation assay. The expression levels of RAGE in ASMCs were analyzed using western blotting assay. RESULTS: Results showed that exogenous S100A8 inhibited the PDGF-induced proliferation of rat ASMCs in a dose- dependent manner with the maximal effect at 1 µg/ml in vitro. Furthermore, when ASMCs was pre-treated with anti-RAGE neutralizing antibody, the inhibitory effect of S100A8 on PDGF-induced proliferation was significantly suppressed. In addition, neither the treatment with S100A8 or PDGF alone nor the pre-treatment with rS100A8 followed by PDGF stimulation affected the expression levels of RAGE. CONCLUSIONS: Our study demonstrated that S100A8 inhibits PDGF-induced ASMCs proliferation in a manner dependent on membrane receptor RAGE.


Assuntos
Animais , Ratos , Fator de Crescimento Derivado de Plaquetas/agonistas , Miócitos de Músculo Liso/efeitos dos fármacos , Calgranulina A/administração & dosagem , Proliferação de Células/efeitos dos fármacos , Receptor para Produtos Finais de Glicação Avançada/efeitos dos fármacos , Células Cultivadas
7.
Braz. j. med. biol. res ; 48(6): 545-552, 06/2015. tab, graf
Artigo em Inglês | LILACS | ID: lil-748222

RESUMO

Abnormal high mobility group protein B1 (HMGB1) activation is involved in the pathogenesis of pulmonary fibrosis. Pulmonary rehabilitation mixture (PRM), which combines extracts from eight traditional Chinese medicines, has very good lung protection in clinical use. However, it is not known if PRM has anti-fibrotic activity. In this study, we investigated the effects of PRM on transforming growth factor-β1 (TGF-β1)-mediated and bleomycin (BLM)-induced pulmonary fibrosis in vitro and in vivo. The effects of PRM on TGF-β1-mediated epithelial-mesenchymal transition (EMT) in A549 cells, on the proliferation of human lung fibroblasts (HLF-1) in vitro, and on BLM-induced pulmonary fibrosis in vivo were investigated. PRM treatment resulted in a reduction of EMT in A549 cells that was associated with attenuating an increase of vimentin and a decrease of E-cadherin. PRM inhibited the proliferation of HLF-1 at an IC50 of 0.51 µg/mL. PRM ameliorated BLM-induced pulmonary fibrosis in rats, with reduction of histopathological scores and collagen deposition, and a decrease in α-smooth muscle actin (α-SMA) and HMGB1 expression. An increase in receptor for advanced glycation end-product (RAGE) expression was found in BLM-instilled lungs. PRM significantly decreased EMT and prevented pulmonary fibrosis through decreasing HMGB1 and regulating RAGE in vitro and in vivo. PRM inhibited TGF-β1-induced EMT via decreased HMGB1 and vimentin and increased RAGE and E-cadherin levels. In summary, PRM prevented experimental pulmonary fibrosis by modulating the HMGB1/RAGE pathway.


Assuntos
Animais , Humanos , Masculino , Medicamentos de Ervas Chinesas/farmacologia , Fibrose Pulmonar/tratamento farmacológico , Fibrose Pulmonar/prevenção & controle , Antibióticos Antineoplásicos , Receptor para Produtos Finais de Glicação Avançada/efeitos dos fármacos , Apoptose/efeitos dos fármacos , Bleomicina , Western Blotting , Células Cultivadas , Colágeno/efeitos dos fármacos , Misturas Complexas/farmacologia , Medicamentos de Ervas Chinesas/uso terapêutico , Transição Epitelial-Mesenquimal/efeitos dos fármacos , Fibroblastos/efeitos dos fármacos , Proteína HMGB1/efeitos dos fármacos , Hidroxiprolina/análise , Imuno-Histoquímica , Pulmão/efeitos dos fármacos , Pulmão/patologia , Fator de Crescimento Derivado de Plaquetas/efeitos dos fármacos , Fibrose Pulmonar/patologia , Distribuição Aleatória , Ratos Sprague-Dawley , Reprodutibilidade dos Testes , Fator de Crescimento Transformador beta1/efeitos dos fármacos
8.
São Paulo; s.n; s.n; 2015. 158 p. graf, tab, ilus.
Tese em Português | LILACS | ID: biblio-881862

RESUMO

Concentrações séricas basais da proteína amiloide sérica A (SAA) estão significativamente aumentadas em pacientes com câncer e alguns autores sugerem uma relação causal. Trabalho anterior do grupo mostrou que a SAA induz a proliferação de duas linhagens de glioblastoma humano e afeta os processos de invasividade in vitro, sustentando um papel pró-tumoral para esta proteína. Com base nesse trabalho, investigamos a abrangência dos efeitos de SAA para outro tipo de célula tumoral e para isso escolhemos um painel de linhagens de melanoma humano e uma linhagem primária obtida a partir de aspirado de linfonodo de paciente com melanoma, por nós isolada. Observamos que apesar da célula precursora de melanomas, isto é, melanócito, não produzir SAA, todas as linhagens de melanoma produziram a proteína e expressaram alguns dos seus receptores. Além disso, quando estas células foram estimuladas com SAA houve uma inibição da proliferação em tempos curtos de exposição (48 horas) e efeitos citotóxicos após um tempo maior (7 dias). A SAA também afetou processos de invasividade e a produção das citocinas IL-6, IL-8 e TNF-α. Aos avaliarmos o efeito da SAA na interação das células de melanoma com células do sistema imune, vimos que a SAA ativou uma resposta imune anti-tumoral aumentando a expressão de moléculas co-estumolatórias, como CD69 e HLA-DR, e sua função citotóxica. Ainda, vimos que a produção de TNF-α, IFN-γ, IL-10, IL-1ß e IL-8 estimuladas por SAA podem contribuir com os efeitos desta. De forma geral estes resultados nos levam a crer que a SAA tem atividade anti-tumoral em melanomas. Finalizando, com base na importância do desenvolvimento da resistência às terapias atuais para o melanoma, observamos que em células resistentes ao PLX4032, um inibidor de BRAF, os efeitos imunomodulatórios induzidos pela SAA estão abolidos, possivelmente identificando um novo componente da resistência


Basal serum concentrations of the protein serum amyloid A are significantly increased in cancer patients and some authors suggest a causal relationship. Previous work of our research group showed that SAA induces proliferation of two cell lines of human glioblastoma and affects invasiveness processes in vitro, supporting a pro-tumor role for this protein. Based on this work, we investigated the extent of SAA effects to another type of tumor cell and we chose a panel of human melanoma cell lines and primary line obtained from a patient with melanoma by lymph node aspirate. Melanoma cells were isolated by us. We observed that while the precursor cells of melanoma, melanocytes, do not produce SAA, all melanoma cell lines expressed the protein and produced some of their receptors. Moreover, when these cells were stimulated with SAA there was an inhibition of proliferation in short exposure times (48 hours) and cytotoxic effects after a longer period (7 days). SAA also affected invasive procedures and the production of the cytokines IL-6, IL-8 and TNF-α. To evaluate the SAA effect in the interaction of melanoma cells with immune system cells, we found that SAA activated an anti-tumor immune response by increasing the expression of co-estimulatory molecules such as CD69 and HLA-DR, and their cytotoxic function. Furthermore, we found that the production of TNF-α, IFN-γ, IL-10, IL-1ß and IL-8 stimulated by SAA can contribute to this effect. In general these results lead us to believe that the SAA has anti-tumor activity in melanomas. Finally, based on the importance of the resistance development to current therapies for melanoma we observed that in cells resistant to PLX4032, a BRAF inhibitor, the immunomodulatory effects induced by SAA are abolished, possibly identifying a new resistance component


Assuntos
Proteína Amiloide A Sérica/análise , Proteína Amiloide A Sérica/efeitos adversos , Melanoma/fisiopatologia , Expressão Gênica , Proteínas Proto-Oncogênicas B-raf/efeitos adversos , Receptor 2 Toll-Like/genética , Receptor 4 Toll-Like/genética , Ensaios de Migração Celular/instrumentação , Receptor para Produtos Finais de Glicação Avançada/genética
9.
Rev. bras. ter. intensiva ; 26(4): 392-396, Oct-Dec/2014. tab, graf
Artigo em Português | LILACS | ID: lil-732925

RESUMO

Objetivo: Avaliar e compreender as implicações clínicas dos níveis plasmáticos de uma isoforma solúvel de um receptor de produtos finais de glicação avançada (do inglês receptor for advanced glycation end products - sRAGE) em diferentes fases da sepse. Métodos: Os valores do sRAGE sérico em pacientes divididos nos grupos controle na unidade de terapia intensiva, sepse grave, choque séptico e recuperação de choque séptico foram analisados do ponto de vista estatístico para avaliar a quantidade (Kruskal-Wallis), variabilidade (teste de Levine) e correlação (teste Spearman rank) em relação a certos mediadores inflamatórios (IL-1 α, IL-6, IL-8, IL-10, IP-10, G-CSF, MCP-1, IFN-γ e TNF-α). Resultados: Não se observaram modificações nos níveis de sRAGE entre os grupos; contudo o grupo com choque séptico demonstrou diferenças na variabilidade do sRAGE em comparação aos demais grupos. Foi relatada, no grupo com choque séptico, uma correlação positiva com todos os mediadores inflamatórios. Conclusão: Os níveis de sRAGE se associaram com desfechos piores nos pacientes com choque séptico. Entretanto, uma análise de correlação estatística com outras citocinas pró-inflamatórias indicou que as vias que levam a esses desfechos são diferentes, dependendo dos níveis de sRAGE. ...


Objective: To evaluate and understand the clinical implications of the plasma levels of a soluble isoform of a receptor for advanced glycation end products (sRAGE) in different stages of sepsis. Methods: Serum sRAGE values in patients who were divided into intensive care unit control, severe sepsis, septic shock and recovery from septic shock groups were statistically analyzed to assess quantity (Kruskal-Wallis), variability (Levine test) and correlation (Spearman rank test) with certain inflammatory mediators (IL-1 α, IL-6, IL-8, IL-10, IP-10, G-CSF, MCP-1, IFN-γ and TNF-α). Results: No changes in sRAGE levels were observed among the groups; however, the septic shock group showed differences in the variability of sRAGE compared to the other groups. A positive correlation with all the inflammatory mediators was reported in the septic shock group. Conclusion: sRAGE levels are associated with worse outcomes in patients with septic shock. However, a statistical correlation analysis with other proinflammatory cytokines indicated that the pathways leading to those outcomes are different depending on the sRAGE levels. Future studies to elucidate the pathophysiological mechanisms involving sRAGE in models of sepsis are of great clinical importance for the safe handling of this biomarker. .


Assuntos
Humanos , Receptor para Produtos Finais de Glicação Avançada/sangue , Mediadores da Inflamação/metabolismo , Choque Séptico/sangue , Biomarcadores/sangue , Estudos de Coortes , Estudos Prospectivos , Choque Séptico/mortalidade , Choque Séptico/fisiopatologia
10.
Acta bioquím. clín. latinoam ; 43(4): 579-587, oct.-dic. 2009. graf, tab
Artigo em Espanhol | LILACS | ID: lil-633089

RESUMO

En los pacientes diabéticos, las lipoproteínas presentan frecuentemente cambios cualitativos y cuantitativos en su composición y varios pasos del metabolismo están alterados. Estas anormalidades contribuyen al incremento del riesgo de enfermedad cardiovascular y se la conoce como "dislipemia aterogénica". En este trabajo se estudiaron en una población de pacientes diabéticos las modificaciones fisicoquímicas por glicación de sus lipoproteínas de baja densidad (LDL), los resultados se compararon con una población control y con ensayos de glicación in vitro. Las LDL se aislaron por precipitación selectiva y las modificaciones se evaluaron por el incremento de fructosamina, el consumo de los residuos e-amino de lisina, guanidinio de arginina y la disminución de la fluorescencia del grupo indol del triptofano. Los procedimientos seleccionados resultan accesibles al laboratorio clínico. Los valores medios para todos los analitos medidos fueron significativamente diferentes de los de la población control (p0,0001); de la comparación del ensayo in vitro pudo deducirse que las alteraciones de los residuos de arginina serían un marcador temprano de las modificaciones por glicación, en tanto que las producidas en los residuos de lisina y triptofano representarían indicadores de las alteraciones de mediano plazo. Vale considerar la utilidad de evaluar simultáneamente en una misma molécula, indicadores de control glucémico tanto de corto como de mediano plazo, teniendo en cuenta su relevancia en la fisiopatología de la ateroesclerosis.


In diabetic patients, lipoproteins usually show qualitative and quantitative changes in their composition and as a consequence, severa! metabolic pathways are altered. These alterations contribute to an increase in the risk of cardiovascular disease, also known as "atherogenic dyslipidemia". The present workstudied the physicochemical modifications by glycation of low density lipoproteins (LDL) in a population of diabetic patients. The results were compared with a control population and with the results obtained from an in vitro glycation assay. LDL were isolated byselective precipitation and the modifications were assessed by the increase in fructosamine level, the decrease of e-amino group of lysine, guanidinio of arginine and indol fluorescence of tryptophan residues. The select methods are available for clinical laboratories. The mean valúes for all the measured analytes were significantly different from those obtained for the control population (p< 0.0001). Taking into account the results of the in vitro kinetlcs assays, it can be assumed that the modifications of the arginine residues would be an early glycation marker while the changes in the lysine and triptophan residues may be considered middle term alterations. It is worth remarking the usefulness of evaluating, early and middle term ¡ndicators of glycaemic control simultaneously in the same molecule. These findings are relevant for the pathophysiology of atherogenesis.


Assuntos
Humanos , Masculino , Feminino , Adulto , Pessoa de Meia-Idade , Diabetes Mellitus/metabolismo , Lipoproteínas LDL/metabolismo , Lipoproteínas LDL/sangue , Complicações do Diabetes , Diabetes Mellitus/sangue , Receptor para Produtos Finais de Glicação Avançada
11.
Acta bioquím. clín. latinoam ; 41(3): 337-346, jul.-sep. 2007. ilus, graf
Artigo em Espanhol | LILACS | ID: lil-633016

RESUMO

La hiperglucemia sostenida incrementa la glicación de proteínas. En particular, las modificaciones en las lipoproteínas de baja densidad (LDL) aumentan su potencial aterogénico. En este trabajo se comparan las modificaciones producidas por la glicación in vitro de LDL aisladas por dos métodos: precipitación selectiva (PS) y ultracentrifugación (UC). Para ello, se determinó el incremento de fructosamina, el consumo de los grupos e-amino de lisina, guanidinio de arginina y la disminución de residuos de triptofano. Para todos los analitos, los resultados cinéticos indicaron diferencias significativas con relación al basal (p<0,05), coincidentes para ambos métodos en el tiempo de aparición y en el porcentaje de variación. La aterogenicidad de las LDL glicadas separadas por PS fue estudiada en cultivos de macrófagos RAW 264.7 evaluando la formación de células espumosas y cuantificando la incorporación de LDL por tinción de los depósitos lipídicos con Oil Red. Los resultados indican que la captación de LDL modificadas aumentó con el tiempo de incubación, siendo mayor la aterogenicidad de las LDL glicadas respecto de las nativas (p<0,001, 1 h a 37 °C). El procedimiento de PS seleccionado, accesible al laboratorio bioquímico clínico, permite evaluar las modificaciones por glicación que sufren las LDL en pacientes diabéticos.


Long-term hyperglycemia increases protein glycation. In particular, modifications in the low-density lipoproteins (LDL) increase their atherogenic potential. In this study, the modifications caused by in vitro glycation of LDL separated by two methods: selective precipitation (SP) and ultracentrifugation (UC) were compared. Increase fructosamine level, decrease of e-amino group of lysine, guanidinio of arginine and triptophan fluorescence were determined. Results showed significant differences vs. basal (p<0.05) for all the tested parameters, with coincidence for the two separation methods both in time and grade of modifications. The atherogenicity of glycated LDL separated by SP was studied in macrophages RAW 264.7 in culture, through the formation of foam cells and the quantification of the dye taken up by the cellular storage lipids. Results show that the uptake of modified LDL by macrophages increased with the time of incubation, being the atherogenicity of glycated LDL greater than native LDL (p<0.001, 1 h at 37 °C). The selected SP procedure, within the facilities of routine biochemical laboratory, enables the evaluation of the modifications caused by glycation in the LDL of diabetic patients.


Assuntos
Humanos , Masculino , Feminino , Adulto , Receptor para Produtos Finais de Glicação Avançada , Lipoproteínas LDL/sangue , Apolipoproteínas , Ultracentrifugação/métodos , Técnicas de Química Analítica/métodos , Técnicas de Cultura de Células/métodos
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