Nogueira, L. P. | bioRxiv Science

bioRxiv2022

Adipose-derived stromal cells preserve pancreatic islet function in a transplantable 3D bioprinted scaffold

Intra-portal islet transplantation is the method of choice for treatment of insulin dependent type 1 diabetes, but its outcome is hindered by limited islet survival due to the immunological and metabolic stress post transplantation. Adipose-derived stromal cells (ASCs) promise to improve significantly the islet micro-environment but an efficient long-term delivery method has not been achieved. We therefore explore the potential of generating ASC enriched islet transplant structure by 3D bioprinting. Here, we fabricate a double-layered 3D bioprinted scaffold for islets and ASCs by using alginate-nanofibrillated cellulose bioink. We demonstrate the diffusion properties of the scaffold and report that human ASCs increase the islet viability, preserve the endocrine function, and reduce pro-inflammatory cytokines secretion in vitro. Intraperitoneal implantation of the ASCs and islets in 3D bioprinted scaffold improve the long-term function of islets in diabetic mice. Our data reveals an important role for ASCs on the islet micro-environment. We suggest a novel cell therapy approach of ASCs combined with islets in a 3D structure with a potential for clinical beta cell replacement therapies at extrahepatic sites.

cell biology↗

bioRxiv2021

3D imaging reveals potential anticipatory responses to increasing intraspecific competition in the Drosophila male reproductive system

Ecological conditions shape (adaptive) responses at the molecular, anatomical, and behavioural levels. Understanding these responses is key to predict the outcomes of intra- and inter-specific competitions and the evolutionary trajectory of populations. Recent technological advances have enabled large-scale molecular (e.g., RNAseq) and behavioural (e.g., computer vision) studies, but the study of anatomical responses to ecological conditions has lagged behind. Here, we highlight the role of X-Ray micro-computed tomography (micro-CT) in generating in vivo and ex vivo 3D imaging of anatomical structures, which can enable insights into adaptive anatomical responses to ecological environments. To demonstrate the application of this method, we manipulated the larval density of Drosophila melanogaster flies and applied micro-CT to investigate the anatomical responses of the male reproductive organs to varying intra-specific competition levels during development. Our data is suggestive of two classes of anatomical responses which broadly agree with sexual selection theory: increasing larval density led to testes and ejaculatory duct to be overall larger (in volume), while the volume of accessory glands and, to a lesser extent, ejaculatory duct decreased. These two distinct classes of anatomical responses might reflect shared developmental regulation of the structures of the male reproductive system. Overall, we show that micro-CT can be an important tool to advance the study of anatomical (adaptive) responses to ecological environments.

evolutionary biology↗