O uso dos inibidores do SGLT2 na insuficiência cardíaca - uma revisão de literatura

Introdução: Os inibidores de SGLT2 (iSGLT2) são medicamentos utilizados e indicados na terapia da diabetes mellitus tipo 2 (DM2). Recentemente, com o primeiro estudo em 2015, foram inseridos também no tratamento da insuficiência cardíaca (IC), apresentando benefícios na mortalidade, IC sintomática e com fração de ejeção reduzida (< 40%), sendo assim, justificado seu uso mesmo em pacientes não portadores da DM2. Objetivos: elucidar os benefícios do uso dos iSGLT2 na IC, apresentando estudos acerca de sua efetividade em tal patologia. Métodos: trata-se de uma revisão de literatura narrativa, na qual foram utilizados bancos de dados como Scielo, Pubmed e Medline, abrangendo o período entre 2015 e 2023, baseando-se em 18 fontes para o estudo. Resultados: os estudos realizados demonstraram efeitos benéficos acerca do uso dos iSGLT2 em portadores de IC, tanto no quesito de morte cardiovascular, quanto em hospitalizações pela doença. Mais recentemente (2022), o estudo DAPA-HF publicou que essa classe medicamentosa é benéfica em portadores de IC com ou sem DM2. Logo depois, o estudo DELIVER mostrou que tanto os portadores de ICFEr, quanto de ICFEp podem se beneficiar do uso dessa medicação. A justificativa da inserção dos iSGLT2 no tratamento e prevenção da IC se deve aos efeitos de inibição da remodelação cardíaca, natriurese e ematopoiese aumentadas, além da redução da pressão glomerular renal. Conclusão: o uso dos iSGLT2 apresentou benefício tanto na prevenção como no tratamento da IC, em pacientes portadores ou não do DM2. Diante disso, são medicamentos que podem ser considerados na rotina desses pacientes

Functional properties of a Brazilian derived mouse embryonic stem cell line

Pluripotent mouse embryonic stem cells (mESC) are cell lines derived from the inner cell mass of blastocyst-stage early mammalian embryos. Since ion channel modulation has been reported to interfere with both growth and differentiation process in mouse and human ESC it is important to characterize the electrophysiological properties of newly generated mESC and compare them to other lines. In this work, we studied the intercellular communication by way of gap junctions in a Brazilian derived mESC (USP-1, generated by Dr. Lygia Pereira's group) and characterized its electrophysiological properties. We used immunofluorescence and RT-PCR to reveal the presence of connexin 43 (Cx43), pluripotency markers and ion channels. Using a co-culture of neonatal mouse cardiomyocytes with mESC, where the heart cells expressed the enhanced Green Fluorescent Protein, we performed dye injections to assess functional coupling between the two cell types observing dye diffusion. The patch-clamp study showed outward currents identified as two types of potassium currents, transient outward potassium current (Ito) and delayed rectifier outward potassium current (Iks), by use of specific drug blockage. Calcium or sodium currents in undifferentiated mESC were not identified. We conclude that USP-1 mESC has functional Cx43 channels establishing intercellular communication among themselves and with cardiomyocytes and has a similar electrophysiological profile compared to other mESC cell lines

Human Menstrual Blood-Derived Mesenchymal Cells as New Human Feeder Layer System for Human Embryonic Stem Cells

Human embryonic stem cells (hESCs) in general require coculture with feeder layers in order to remain undifferentiated. However, the use of animal-derived feeder layers is incompatible with the clinical setting. The objective of this work was to investigate whether human menstrual blood-derived mesenchymal cells (MBMCs) can substitute mouse embryonic fibroblasts (MEFs) as a feeder layer for H9-hESCs. Both feeder cell types were isolated and cultured in DMEM F-12 and high glucose DMEM, respectively. After three passages, they were inactivated with mitomycin C. To test MBMC feeder layer capacity, hESCs were grown over MBMCs and MEFs under standard conditions. hESC growth, proliferation, survival, and maintenance of the undifferentiated state were evaluated. hESCs grown over MBMCs preserved their undifferentiated state presenting standard morphology, expressing alkaline phosphatase, transcription factors OCT3/4, SOX2, and NANOG by RT-PCR and SSEA-4 and OCT3/4 by immunofluorescence assays. It is noteworthy that none of the feeder cells expressed these proteins. The average colony size of the hESCs on MBMCs was higher when compared to MEFs ( p &lt; 0.05; mean ± SD, n = 3). Growth factor analysis revealed amplification of the transcripts for FGF-2, BMP4, TGF-β, VEGF, and PEDF by RT-PCR in MBMCs and MEFs before and after inactivation. Furthermore, similar embryoid body formation, size, and morphology were observed in both feeder layers. In addition, EBs expressed marker genes for the three germ layers cultured on both feeder cells. In conclusion, MBMCs are able to maintain hESCs in an undifferentiated state with comparable efficiency to MEFs. Therefore, MBMCs are a suitable alternative to animal-derived feeder layers for growing hESCs. </jats:p

Human Menstrual Blood-Derived Mesenchymal Cells as a Cell Source of Rapid and Efficient Nuclear Reprogramming

Induced pluripotent stem cells (iPSCs) were originally generated by forced ectopic expression of four transcription factors genes—OCT4, KLF4, SOX2, and c-MYC—in fibroblasts. However, the efficiency of iPSCs obtention is extremely low, and reprogramming takes about 20 days. We reasoned that adult cells showing basal expression of core embryonic stem (ES) cell regulator genes could be a better cell source for reprogramming. Menstrual blood-derived mesenchymal cells (MBMCs) are multipotent cells that show detectable levels of some of the core ES cells regulators. The aim of this study was to determine whether reprogramming efficiency could be increased by using MBMCs as a cell source to generate iPSCs. MBMCs were transduced with recombinant retroviruses expressing the coding regions of OCT4, SOX2, and KLF4 genes. Cells with high nucleus/cytoplasm ratio can be detected about 5 days of posttransduction, and colonies of typical ES-like cells begun to appear after 7 days. At day 15, colonies were picked up and expanded for characterization. Most of the clones were morphologically identical to ES cells and positive at the mRNA and protein levels for all pluripotency markers tested. The clones are capable of forming embryoid bodies and to differentiate in vitro into cells of the three germ cell layers. Our results show that the reprogramming was faster and with efficiency around 2–5%, even in the absence of ectopic expression of c-MYC. To date, this is the first study showing MBMCs as a cell source for nuclear reprogramming. </jats:p

Lycopene and beta-carotene induce growth inhibition and proapoptotic effects on ACTH-secreting pituitary adenoma cells.

Pituitary adenomas comprise approximately 10-15% of intracranial tumors and result in morbidity associated with altered hormonal patterns, therapy and compression of adjacent sella turcica structures. The use of functional foods containing carotenoids contributes to reduce the risk of chronic diseases such as cancer and vascular disorders. In this study, we evaluated the influence of different concentrations of beta-carotene and lycopene on cell viability, colony formation, cell cycle, apoptosis, hormone secretion, intercellular communication and expression of connexin 43, Skp2 and p27(kip1) in ACTH-secreting pituitary adenoma cells, the AtT20 cells, incubated for 48 and 96 h with these carotenoids. We observed a decrease in cell viability caused by the lycopene and beta-carotene treatments; in these conditions, the clonogenic ability of the cells was also significantly decreased. Cell cycle analysis revealed that beta-carotene induced an increase of the cells in S and G2/M phases; furthermore, lycopene increased the proportion of these cells in G0/G1 while decreasing the S and G2/M phases. Also, carotenoids induced apoptosis after 96 h. Lycopene and beta-carotene decreased the secretion of ACTH in AtT20 cells in a dose-dependent manner. Carotenoids blocked the gap junction intercellular communication. In addition, the treatments increased the expression of phosphorylated connexin43. Finally, we also demonstrate decreased expression of S-phase kinase-associated protein 2 (Skp2) and increased expression of p27(kip1) in carotenoid-treated cells. These results show that lycopene and beta-carotene were able to negatively modulate events related to the malignant phenotype of AtT-20 cells, through a mechanism that could involve changes in the expression of connexin 43, Skp2 and p27(kip1); and suggest that these compounds might provide a novel pharmacological approach to the treatment of Cushing's disease