A beta cell subset with enhanced insulin secretion and glucose metabolism is reduced in type 2 diabetes.

The pancreatic islets are composed of discrete hormone-producing cells that orchestrate systemic glucose homeostasis. Here we identify subsets of beta cells using a single-cell transcriptomic approach. One subset of beta cells marked by high CD63 expression is enriched for the expression of mitochondrial metabolism genes and exhibits higher mitochondrial respiration compared with CD63lo beta cells. Human and murine pseudo-islets derived from CD63hi beta cells demonstrate enhanced glucose-stimulated insulin secretion compared with pseudo-islets from CD63lo beta cells. We show that CD63hi beta cells are diminished in mouse models of and in humans with type 2 diabetes. Finally, transplantation of pseudo-islets generated from CD63hi but not CD63lo beta cells into diabetic mice restores glucose homeostasis. These findings suggest that loss of a specific subset of beta cells may lead to diabetes. Strategies to reconstitute or maintain CD63hi beta cells may represent a potential anti-diabetic therapy.

Testosterona y homicidio: aspectos neuroendocrines de la agresión / Testosterone and homicide: neuroendocrine aspects of aggression

Resumen Introducción. Las tasas de homicidio, suicidio y agresión son mayores en el sexo masculino; la testosterona podría desempeñar un papel importante en el desarrollo de estos comportamientos. Objetivo. Realizar una revisión de los aspectos endocrinos y neurobiológicos de la testosterona y su relación con comportamientos agresivos, homicidas y suicidas. Materiales y métodos. Se realizó una revisión narrativa con diferentes estrategias de búsqueda en PubMed, SpringerLink, ScienceDirect y SciELO. Se incluyeron artículos de investigación, revisiones y reportes de caso publicados en español y en inglés entre 2002 y 2018. Resultados. De los 66 estudios incluidos en la revisión, más del 50% asociaron el comportamiento agresivo u homicida con niveles elevados de testosterona, hormona que podría modular la actividad de las vías cerebrales serotoninérgicas y dopaminérgicas involucradas en el comportamiento agresivo por medio de receptores androgénicos y estrogénicos. Se encontraron relaciones entre uso de esteroides anabólicos y homicidio, y entre testosterona circulante en mujeres y rasgos de personalidad antisocial. Asimismo, se observaron cambios de concentraciones séricas de testosterona en sujetos con tendencias suicidas. Conclusión. La información encontrada en la revisión sugiere que sí existe una asociación entre los niveles de testosterona y el desarrollo de comportamientos agresivos, homicidas y suicidas.

Abstract Introduction: Homicide, suicide, and assault rates are higher in males. Testosterone may play an important role in the development of these behaviors. Objective: To review the endocrine and neurobiological aspects of testosterone and its relationship with aggressive, homicidal and suicidal behaviors. Materials and methods: A literature review was conducted using different search strategies in the PubMed, SpringerLink, ScienceDirect and SciELO databases. Research articles, reviews and case reports published in Spanish and English between 2002 and 2018 were included. Results: Out of the 66 studies included in the review, over 50% reported an association between aggressive or homicidal behavior with high levels of testosterone, a hormone that may modulate the activity of serotonergic and dopaminergic brain pathways involved in aggressive behavior via androgen and estrogen receptors. Associations between anabolic steroid use and homicide, and between circulating testosterone in women and antisocial personality traits were found. Changes in serum testosterone concentrations were also observed in individuals with suicidal tendencies. Conclusion: The information found in this review suggests that there is indeed an association between testosterone levels and the development of aggressive, homicidal and suicidal behaviors.