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).

A critical review of the applicability of serological screening for Leishmaniasis in blood banks in Brazil.

Leishmaniasis is a group of diseases caused by several species of protozoa. It is a major public health concern in its visceral form, accounting annually for 59,000 deaths, and an estimated 12 million infected patients per year. The importance of VL resides not only in its high incidence and wide distribution but also in the possibility of the disease progressing to the severe and lethal forms, especially in children and immunosuppressed individuals, when associated with malnutrition and concomitant infections. This study is a bibliographical review, aiming to understand the sensitivity and specificity parameters of the tests used to detect Leishmaniasis, as well as to understand if there is any relevance in proposing a serological screening for Leishmaniasis in blood banks. In general, we observed that there are currently several types of tests for detecting Leishmaniasis: parasitological, serological and molecular. In such tests, many serological methods and kits are available for the detection of asymptomatic visceral leishmaniasis, but there is variability in sensitivity and specificity among the methods. The gold standard for the diagnosis of visceral leishmaniasis is the parasitological method, through the aspiration of bone marrow, with higher sensitivity by splenic puncture. Due to the relevance of the disease and the available data from research centers, there is evidence to propose a transfusion serological screening for visceral Leishmaniasis, pointing to the need for further studies.

Therapy With Mesenchymal Stem Cells in Parkinson Disease: History and Perspectives.

BACKGROUND: Parkinson disease (PD) is a neurodegenerative disorder affecting the basal nuclei, causing motor and cognitive disorders. Bearing in mind that standard treatments are ineffective in delaying the disease progression, alternative treatments capable of eliminating symptoms and reversing the clinical condition have been sought. Possible alternative treatments include cell therapy, especially with the use of mesenchymal stem cells (MSC). REVIEW SUMMARY: MSC are adult stem cells which have demonstrated remarkable therapeutic power in parkinsonian animals due to their differentiation competence, migratory capacity and the production of bioactive molecules. This review aims to analyze the main studies involving MSC and PD in more than a decade of studies, addressing their different methodologies and common characteristics, as well as suggesting perspectives on the application of MSC in PD. CONCLUSIONS: The results of MSC therapy in animal models and some clinical trials suggest that such cellular therapy may slow the progression of PD and promote neuroregeneration. However, further research is needed to address the limitations of an eventual clinical application.