Eucommia ulmoides extract attenuates angiotensin II-induced cardiac microvascular endothelial cell dysfunction by inactivating p53

Abstract Angiotensin II (AngII) causes endothelial dysfunction. Eucommia ulmoides extract (EUE) is documented to manipulate AngII, but its impact on cardiac microvascular endothelial cell (CMVEC) function remains unknown. This study determines the effects of EUE on AngII-treated CMVECs. CMVECs were treated with different concentrations of AngII or EUE alone and/or the p53 protein activator, WR-1065, before AngII treatment, followed by examinations of the apoptotic, migratory, proliferative, and angiogenic capacities and nitric oxide (NO), p53, von Willebrand factor (vWF), endothelin (ET)-1, endothelial NO synthase (eNOS), manganese superoxide dismutase (MnSOD), hypoxia-inducible factor (HIF)-1α, and vascular endothelial growth factor (VEGF) levels. AngII induced CMVEC dysfunction in a concentration-dependent manner. EUE enhanced the proliferative, migratory, and angiogenic capacities and NO, MnSOD, and eNOS levels but repressed apoptosis and vWF and ET-1 levels in AngII-induced dysfunctional CMVECs. Moreover, AngII increased p53 mRNA levels, p-p53 levels in the nucleus, and p53 protein levels in the cytoplasm and diminishes HIF-1α and VEGF levels in CMVECs; however, these effects were counteracted by EUE treatment. Moreover, WR-1065 abrogated the mitigating effects of EUE on AngII-induced CMVEC dysfunction by activating p53 and decreasing HIF-1α and VEGF expression. In conclusion, EUE attenuates AngII-induced CMVEC dysfunction by upregulating HIF-1α and VEGF levels via p53 inactivation

Sunitinib induced resistance of endothelial cells by up-regulating P-glycoprotein and PI3K/Akt pathway

Abstract Drug resistance is a crucial obstacle to achieve satisfactory chemotherapeutic effects. Numerous studies have shown that the PI3K/Akt signaling pathway plays a significant role in various processes of cellular events and tumor progression, while few studies have focused on the PI3K/Akt signaling pathway in drug resistance of endothelial cells. The present study aims to explore the relationship of PI3K/Akt signaling and cellular resistance to anticancer drugs in human microvessel endothelial cells (HMEC-1). We established stable sunitinib-resiatant human microvessel endothelial cells (HMEC-su) after long-term exposure to sunitinib (a small-molecule tyrosine kinase receptor inhibitor) for 12 months. HMEC-su showed significant alternations of cell morphology and exhibited a 2.32-fold higher IC50 of sunitinib than parental HMEC-1 cells. Expression of P-glycoprotein (P-gp) and breast cancer-resistance protein (ABCG2) which mediates drug efflux, increased significantly in HMEC-su lines compared with HMEC-1 cells by western blots assay. Our study further demonstrates that LY294002 (blocking the PI3K/Akt pathway) enhances the sensibility of HMEC-su to suntinib and inhibits the gene transcription and protein expression of P-gp, ABCG2 in HMEC-su cells. In conclusion, these results indicate that LY294002 could reverse P-gp and ABCG2 mediated-drug resistance to sunitinib in HMEC-su cells by inhibiting PI3K/Akt signaling.

Quantitative analysis of effects of salvianic acid a combined with hydroxy safflower yellow a on rat endothelial cells after hypoxic injury using the combination index method

Abstract Cerebrovascular disease is the second most serious disease in the world. It has the features of high morbidity, high mortality and recurrence rate. Numerous research on the compatibility of Chinese medicine with effective ingredients of cerebral ischemia has been made during the past decades. The purpose of this study is to quantitatively analyze the combined pharmacological effect of effective ingredients in Danshen and Honghua (Dan Hong) on rat microvascular endothelial cells after gradually oxygen-glucose deprivation. The experimental concentration range for the compatibility of two effective ingredients were determined in the preliminary experiments by Cell Counting kit-8 (CCK-8) method. Drugs were added to rat brain microvascular endothelial cells at a non-toxic dose level. After that, the cells were cultured for 12 h, and placed in a hypoxic environment. Finally, the cell survival rate was used as a measure of drug effect. In order to determine synergism or antagonism, the combination index (CI)-isobologram method was performed to analyze the data from the experiments. Based on this theory, the potencies of each drug and the shapes of their does-effect curves are both taken into account. The results show that the synergism or the antagonism between two effective ingredients compatibility change with different proportion and dosage. Furthermore, it can be seen from the results of these experiments that when these drugs are used in combination, the dosage required to achieve the same therapeutic effects is greatly reduced compared with the case of single one. It is worth mentioning that our experiments also prove that the median-effect equation and the CI method can be applied in the field of traditional Chinese medicine.

Protein malnutrition effects of perivascular bone marrow microenvironment on the regulation of hematopoiesis / Efeitos da desnutrição proteica sobre o microambiente perivascular medular na regulação da hematopoese

Protein malnutrition (PM) causes anemia and leukopenia by reduction of hematopoietic precursors and impaired production of mediators that induce hematopoiesis, as well as structural and ultrastructural changes in the bone marrow (BM) extracellular matrix. Hematopoiesis occurs in the bone marrow (BM) in distinct regions called niches, which modulate the processes of differentiation, proliferation and self-renewal of the hematopoietic stem cell (HSC). The perivascular niche, composed mainly by mesenchymal stem cells (MSC) and endothelial cells (EC), is the major modulator of HSC and its function extends to the migration of mature hematopoietic cells into the peripheral blood through the production of cytokines and growth factors. Thus, our hypothesis is that PM changes the perivascular niche and our objective is to evaluate whether PM affects the modulatory capacity of MSC and EC on hematopoiesis. C57BL/6 male mice were divided into Control and Malnourished groups, which received for 5 weeks, respectively, a normal protein diet (12% casein) and a low protein diet (2% casein). After this period, animals were euthanized, nutritional and hematological evaluations were performed, featuring the PM. We performed leukemic myelo-monoblasts cells transplantation and observed that these cells have a lower proliferation rate and are rather in the cell cycle G0/G1 phases in malnourished mice, indicating that the BM microenvironment is compromised in PM. MSC were isolated, characterized and differentiated in vitro into EC cells, which were evidenced by CD31 and CD144 markers. We performed the quantification of HSC and hematopoietic progenitors, as well as some regulators of proliferation and differentiation, ex vivo and after cultures with MSC or EC. We observed that PM reduces HSC and hematopoietic progenitors ex vivo. In PM, MSC promote increase in HSC and suppress hematopoietic differentiation, whereas ECs induce cell cycle arrest. Additionally, we verified that PM affects granulopoesis by decreasing the expression of G-CSFr in granule-monocytic progenitors. Thus, we conclude that PD compromises hematopoiesis due to intrinsic alterations in HSC, as well as alterations in the medullary perivascular niche

A desnutrição proteica (DP) provoca anemia e leucopenia decorrente da redução de precursores hematopoéticos e comprometimento da produção de mediadores indutores da hematopoese. A hematopoese ocorre na medula óssea (MO) em regiões distintas chamadas de nichos, que modulam os processos de diferenciação, proliferação e auto renovação da célula tronco hematopoiética (CTH). O microambiente perivascular, composto principalmente por células tronco mesenquimais (CTM) e células endoteliais (CE), é o principal modulador das CTH e sua função se estende até a migração das células hematopoiéticas maduras para o sangue periférico, através da produção de citocinas e fatores de crescimento. Dessa forma, nossa hipótese é que a DP altera o microambiente perivascular e objetivamos avaliar se a DP afeta a capacidade modulatória das CTM e CE sobre a hematopoese. Utilizamos camundongos C57BL/6 machos, divididos em grupos Controle e Desnutrido, sendo que o grupo Controle recebeu ração normoproteica (12% caseína) e o grupo Desnutrido recebeu ração hipoproteica (2% caseína), ambos durante 5 semanas. Após este período, os animais foram eutanasiados, foi realizada a avaliação nutricional e hematológica, caracterizando a DP. Realizamos transplantes de mielomonoblastos leucêmicos e observamos que estas células apresentam menor taxa de proliferação e se encontram em maior quantidade nas fases G0/G1 do ciclo celular em camundongos desnutridos, indicando que o microambiente medular está comprometido. Isolamos CTM, que foram caracterizadas e diferenciadas in vitro em CE, o que foi evidenciado pelos marcadores CD31 e CD144. Quantificamos CTH e progenitores hematopoéticos, bem como reguladores de proliferação e diferenciação, ex vivo e após culturas com CTM ou CE. Observamos que a DP reduz CTH e progenitores hematopoéticos ex vivo. Na DP, as CTM promovem incremento de CTH e suprimem a diferenciação hematopoética, enquanto que as CE induzem parada no ciclo celular. Adicionalmente, observamos que a DP afeta a granulopoese por diminuição da expressão de G-CSFr nos progenitores grânulo-monocíticos. Dessa forma, concluímos que a DP compromete a hematopoese por alterações intrínsecas na CTH, como também por alterações ocasionadas no microambiente perivascular medular

Aspectos fisiopatológicos e estruturais da vasculopatia pulmonar / Structure and pathophysiology of pulmonary vascular disease

A patogenia da doença vascular pulmonar é multifatorial, sendo o produto da interação de aspectos genéticos, celulares e moleculares, que são individuais , com fatores externos de risco, como a estímulos injuriantes diversos. O remodelamento da circulação pulmonar compreende alterações nas células das tres túnicas arteriais(íntima, média e adventícia), que culminam com proliferação celular e oclusão da luz vascular. Outros elementos participam do processo, como células inflamatórias e plaquetas, que liberam substâncias promotoras de proliferação celular e com ação no tônus vascular. As células endoteliais têm papel-chave no processo patogenético, apresentando disfunção que interfere na homeostase vascular. A trombose é também um fator importante na evolução das lesões morfológicas. Dentre as substâncias que influênciam o remodelamento, muitas são produzidas pelas próprias células da parede(como endotelina, prostaciclinas, etc).) e outras têm receptores nos diferentes tipos celulares. Contrapõe-se à proliferação celular induzida por fatores de crescimento (fator de crescimento e fator de crescimento derivado das plaquetas - PDGF e fator de crescimento do endotelio vascular - VEGF) e facilitada por enzimas que degradam a matriz extracelular, o mecanismo de apoptose ou a morte celular programada.

A terapia celular no tratamento da isquemia crítica dos membros inferiores / Cell therapy for the treatment of critical ischemia of the lower limbs

Os autores fazem um histórico sobre as pesquisas com células-tronco embrionárias e do cordão umbilical, suas respectivas vantagens e desvantagens. Seguem com as discussões sobre células-tronco adultas, sua definição, histórico, fontes e participação nos processos de regeneração tecidual, particularmente no endotélio. Ressaltam a importância de fatores que mobilizam as células-tronco adultas a partir da medula óssea: citocinas, angiopoietinas e outros fatores de crescimento. As células-tronco adultas mobilizam-se sob a forma de células endoteliais progenitoras, que têm origem comum com as células endoteliais a partir dos hemangioblastos. Os fatores de mobilização manifestam-se em condições de hipoxia e fazem com que as células endoteliais progenitoras se localizem nos locais de isquemia para produzir a neovasculogênese, que se faz por três possíveis mecanismos: a angiogênese (formação de novos capilares a partir de brotos de capilares já existentes), a arteriogênese (relacionada à circulação colateral) e a vasculogênese (vasos realmente novos). Fazem, a seguir, uma análise da literatura relativa à experimentação animal e aos estudos clínicos. Concluem ressaltando que as células-tronco adultas, embora tenham um grande potencial de uso, ainda demandam muito estudo e pesquisa para se firmar como método terapêutico.