Organoides de cérebro como modelos de doenças de Alzheimer e Parkinson: uma revisão narrativa sobre as perspectivas para medicina regenerativa e personalizada / Brain organoids as models of Alzheimer's and Parkinson's diseases: a narrative review on perspectives for regenerative and personalized medicine

Há muitos anos a cultura celular bidimensional (2D) é utilizada como modelo de estudo de doenças, possuindo grande importância na medicina regenerativa, apesar de ainda conter limitações significativas. A fim de contornar essas limitações, a cultura celular tridimensional (3D) propõe uma organização mais complexa e sustentável que pode ser produzida a partir de células-tronco adultas (ASCs), células-tronco embrionárias (ESCs) ou células-tronco pluripotentes induzidas (iPSCs). A cultura 3D possibilitou o cultivo de células em um ambiente mais próximo do fisiológico, levando à formação de distintos tecidos órgãos-específicos. Em outras palavras, a cultura de células 3D possibilita a criação de estruturas orgânicas muito semelhantes aos órgãos de um ser humano, tanto estruturalmente, quanto funcionalmente. Desse modo, tem-se o que é chamado de organoides. O uso dos organoides tem crescido exponencialmente em ambientes in vitro, permitindo a análise e observação dos diversos fenômenos fisiológicos existentes. Como exemplo, pode-se citar os organoides cerebrais ("mini-brains") reproduzidos in vitro buscando delinear as peculiaridades e complexidades do cérebro humano, com o objetivo de compreender algumas disfunções neurológicas que acometem esse sistema, como as duas principais doenças neurodegenerativas: Doenças de Alzheimer e Parkinson. Portanto, os organoides cerebrais podem permitir notável avanço da medicina regenerativa aplicada a doenças neurodegenerativas, já que esses "mini-brains" podem ser produzidos a partir de células do próprio paciente. Isso permitirá intervenções personalizadas, como testagens farmacológicas, a fim de definir qual seria o melhor tratamento medicamentoso. Consequentemente, essa tecnologia pode permitir terapias mais eficientes e individualizadas - o que é fundamental para a Medicina Personalizada (AU).

For many years, two-dimensional (2D) cell culture has been used as a model to study diseases, having great importance in regenerative medicine, despite still having significant limitations. In order to circumvent these limitations, three-dimensional (3D) cell culture proposes a more complex and sustainable organization that can be produced from adult stem cells (ASCs), embryonic stem cells (ESCs) or induced pluripotent stem cells (iPSCs). The 3D culture enabled the cultivation of cells in an environment closer to the physiological one, leading to the formation of different organ-specific tissues. In other words, 3D cell culture makes it possible to create organic structures very similar to the organs of a human being, both structurally and functionally. In this way, we have what are called organoids. The use of organoids has grown exponentially in in vitro environments, allowing the analysis and observation of the various existing physiological phenomena. As an example, we can mention the brain organoids ("mini-brains") reproduced in vitro, seeking to delineate the peculiarities and complexities of the human brain, in order to understand some neurological dysfunctions that affect this system, such as the two main neurodegenerative diseases: Alzheimer's and Parkinson's Diseases. Therefore, brain organoids may allow a remarkable advance in regenerative medicine applied to neurodegenerative diseases, as these "mini-brains" can be produced from the patient's own cells. This will allow for personalized interventions, such as drug testing, in order to define what would be the best drug treatment. Consequently, this technology can enable more efficient and individualized therapies - which is fundamental for Personalized Medicine (AU).

Chronic Lymphocytic Leukemia (CLL): evaluation of AKT protein kinase and microRNA gene expression related to disease pathogenesis

Abstract The present study evaluated 56 patients diagnosed with Chronic Lymphocytic Leukemia (CLL) and a control group of 44 clinically healthy subjects with no previous history of leukemia. Genetic expressions of AKT and microRNAs were evaluated by quantitative PCR (qPCR). A significant increase in AKT gene expression in patients when compared to controls was observed (p = 0.017). When the patients were stratified according to Binet subgroups, a significant difference was observed between the subgroups, with this protein kinase appearing more expressed in the B+C subgroup (p = 0.013). Regarding miRNA expression, miR-let-7b and miR-26a were reduced in CLL patients, when compared to controls. However, no significant differences were observed in these microRNA expressions between the Binet subgroups (A versus B+C). By contrast, miR-21 to miR-27a oncogenes showed no expression difference between CLL patients and controls. AKT protein kinase is involved in the signaling cascade that occurs with BCR receptor activation, leading to increased lymphocyte survival and protection against the induction of cell death in CLL. Thus, increased AKT protein kinase expression and the reduction of miR-let-7b and miR-26a, both tumor suppressors, may explain increased lymphocyte survival in CLL patients and may be promising markers for the prognostic evaluation of this disease.