Ensayos aleatorizados publicados por instituciones ubicadas en Perú: estudio bibliométrico del periodo 2000 a 2022

Objetivo: Caracterizar la producción científica de ensayos aleatorizados por instituciones ubicadas en Perú del 01 de enero de 2000 al 30 de diciembre de 2022. Materiales y Métodos: Estudio bibliométrico, se revisaron dos bases de datos (MEDLINE y SciELO). Se incluyeron artículos originales en la que al menos un autor consignó como filiación una institución ubicada en Perú. Se caracterizó la producción científica según: área temática, participación de instituciones ubicadas en Perú, revistas científicas en las que se publicaron los artículos, y aprobación de los estudios por un Comité de Ética en Investigación (CEI). Resultados: Se analizó un total de 402 artículos, se evidenció una tendencia creciente de la producción científica, pasando de seis en el año 2000 a 39 en el año 2021, el área temática predominante es la infecciosa, las dos primeras instituciones con mayor número de ensayos aleatorizados pertenecen al sector educación, 189 (47,0%) artículos fueron publicados en revistas de Estados Unidos, en 37 (9,2%) artículos no se consigna información de aspectos éticos o no se declara explícitamente si fue o no aprobado por un CEI. Conclusión: Hay una tendencia creciente de la producción científica sobre este diseño de estudio, el área temática predominante es la infecciosa, las instituciones peruanas más productivas pertenecen al sector educación, cerca de la mitad de los artículos fueron publicados en revistas de Estados Unidos, y en una décima parte de los artículos no se señala explícitamente si el estudio fue o no aprobado por un CEI.

Objetive: To characterize the scientific production of randomized trials by institutions located in Peru from January 1, 2000 to December 30, 2022. Materials and methods: Bibliometric study, two databases (MEDLINE and SciELO) were reviewed. Original articles were included in which at least one author stated an institution located in Peru as affiliation. Scientific production was characterized according to: thematic area, participation of institutions located in Peru, scientific journals in which the articles were published, and approval of the studies by a Research Ethics Committee (REC). Results: A total of 402 articles were analyzed, a growing trend in scientific production was evidenced, going from six in the year 2000 to 39 in the year 2021, the predominant thematic area is infectious, the first two institutions with the highest number of randomized trials belong to the education sector, 189 (47.0%) articles were published in journals in the United States, in 37 (9.2%) articles there is no information on ethical aspects or it is not explicitly stated whether or not it was approved by a CEI. Conclusions: There is a growing trend of scientific production on this study design, the predominant thematic area is infectious, the most productive Peruvian institutions belong to the education sector, about half of the articles were published in journals in the United States, and in a tenth part of the articles do not explicitly state whether or not the study was approved by an REC.

Gangliosides interact with synaptotagmin to form the high-affinity receptor complex for botulinum neurotoxin B.

Botulinum neurotoxin type B (BoNT/B) recognizes nerve terminals by binding to 2 receptor components: a polysialoganglioside, predominantly GT1b, and synaptotagmin 1/2. It is widely thought that BoNT/B initially binds to GT1b then diffuses in the plane of the membrane to interact with synaptotagmin. We have addressed the hypothesis that a GT1b-synaptotagmin cis complex forms the BoNT/B receptor. We identified a consensus glycosphingolipid-binding motif in the extracellular juxtamembrane domain of synaptotagmins 1/2 and confirmed by Langmuir monolayer, surface plasmon resonance, and circular dichroism that GT1b interacts with synaptotagmin peptides containing this sequence, inducing α-helical structure. Molecular modeling and tryptophan fluorescence spectroscopy were consistent with the intertwining of GT1b and synaptotagmin, involving cis interactions between the oligosaccharide and ceramide moieties of GT1b and the juxtamembrane and transmembrane domains of synaptotagmin, respectively. Furthermore, a point mutation on synaptotagmin, located outside of the BoNT/B-binding segment, inhibited GT1b binding and blocked GT1b-induced potentiation of BoNT/B binding to synaptotagmin-expressing cells. Our findings are consistent with a model in which a preassembled GT1b-synaptotagmin complex constitutes the high-affinity BoNT/B receptor.

Common molecular mechanism of amyloid pore formation by Alzheimer's ß-amyloid peptide and α-synuclein.

Calcium-permeable pores formed by small oligomers of amyloid proteins are the primary pathologic species in Alzheimer's and Parkinson's diseases. However, the molecular mechanisms underlying the assembly of these toxic oligomers in the plasma membrane of brain cells remain unclear. Here we have analyzed and compared the pore-forming capability of a large panel of amyloid proteins including wild-type, variant and truncated forms, as well as synthetic peptides derived from specific domains of Aß1-42 and α-synuclein. We show that amyloid pore formation involves two membrane lipids, ganglioside and cholesterol, that physically interact with amyloid proteins through specific structural motifs. Mutation or deletion of these motifs abolished pore formation. Moreover, α-synuclein (Parkinson) and Aß peptide (Alzheimer) did no longer form Ca(2+)-permeable pores in presence of drugs that target either cholesterol or ganglioside or both membrane lipids. These results indicate that gangliosides and cholesterol cooperate to favor the formation of amyloid pores through a common molecular mechanism that can be jammed at two different steps, suggesting the possibility of a universal therapeutic approach for neurodegenerative diseases. Finally we present the first successful evaluation of such a new therapeutic approach (coined "membrane therapy") targeting amyloid pores formed by Aß1-42 and α-synuclein.

Comparison of the amyloid pore forming properties of rat and human Alzheimer's beta-amyloid peptide 1-42: Calcium imaging data.

The data here consists of calcium imaging of human neuroblastoma SH-SY5Y cells treated with the calcium-sensitive dye Fluo-4AM and then incubated with nanomolar concentrations of either human or rat Alzheimer's ß-amyloid peptide Aß1-42. These data are both of a qualitative (fluorescence micrographs) and semi-quantitative nature (estimation of intracellular calcium concentrations of cells probed by Aß1-42 peptides vs. control untreated cells). Since rat Aß1-42 differs from its human counterpart at only three amino acid positions, this comparative study is a good assessment of the specificity of the amyloid pore forming assay. The interpretation of this dataset is presented in the accompanying study "Broad neutralization of calcium-permeable amyloid pore channels with a chimeric Alzheimer/Parkinson peptide targeting brain gangliosides" [1].

Broad neutralization of calcium-permeable amyloid pore channels with a chimeric Alzheimer/Parkinson peptide targeting brain gangliosides.

Growing evidence supports a role for brain gangliosides in the pathogenesis of neurodegenerative diseases including Alzheimer's and Parkinson's. Recently we deciphered the ganglioside-recognition code controlling specific ganglioside binding to Alzheimer's ß-amyloid (Aß1-42) peptide and Parkinson's disease-associated protein α-synuclein. Cracking this code allowed us to engineer a short chimeric Aß/α-synuclein peptide that recognizes all brain gangliosides. Here we show that ganglioside-deprived neural cells do no longer sustain the formation of zinc-sensitive amyloid pore channels induced by either Aß1-42 or α-synuclein, as assessed by single-cell Ca(2+) fluorescence microscopy. Thus, amyloid channel formation, now considered a key step in neurodegeneration, is a ganglioside-dependent process. Nanomolar concentrations of chimeric peptide competitively inhibited amyloid pore formation induced by Aß1-42 or α-synuclein in cultured neural cells. Moreover, this peptide abrogated the intracellular calcium increases induced by Parkinson's-associated mutant forms of α-synuclein (A30P, E46K and A53T). The chimeric peptide also prevented the deleterious effects of Aß1-42 on synaptic vesicle trafficking and decreased the Aß1-42-induced impairment of spontaneous activity in rat hippocampal slices. Taken together, these data show that the chimeric peptide has broad anti-amyloid pore activity, suggesting that a common therapeutic strategy based on the prevention of amyloid-ganglioside interactions is a reachable goal for both Alzheimer's and Parkinson's diseases.