Development of 3D cell-printed tissue-specific multiple- organ on-a-chip for type 2 diabetes and its complication

Abstract

Type 2 diabetes (T2D) is a metabolic disease impacting various organs and giving rise to numerous complications, contributing to over 1.6 million annual deaths. Diabetic retinopathy (DR), a consequential complication of diabetes, stands out as a leading cause of blindness and is increasingly prevalent, escalating by approximately 30% each year among diabetes patients. The causes of T2D are diverse, with obesity emerging as a prominent factor. The incidence of T2D has shown a significant uptick, paralleling the swift rise in the obese population. Obesity stems from the excessive buildup of adipose tissue (AT), categorized into subcutaneous AT (sAT) and visceral AT (vAT), each possessing distinct attributes. Notably, there is heightened paracrine communication between adipocytes and macrophages in vAT compared to sAT. This dynamic leads to an amplified representation of inflammatory molecules in macrophages within vAT. These heightened molecules stop the intracellular insulin signaling network (IISN), consequently contributing to the pathology of T2D. Multiple clinical studies have substantiated this process. Therefore, the primary pathogenic mechanism of T2D is linked to the excessive accumulation of vAT, inducing inflammation. Presently, there is a notable absence of in vitro models that precisely replicate the molecular intricacies of T2D pathophysiology. In response to this gap, there is an active pursuit of creating in vitro models through various tissue engineering methods. Among these, decellularized extracellular matrix (dECM) bioinks have garnered attention as they can mimic tissue-specific microenvironments. Additionally, three-dimensional (3D) printing technology is extensively employed for creating precise and reproducible platforms. The amalgamation of these technologies has resulted in the development of 3D cell-printing technique using cell-encapsulated bioink. This innovative approach enables the production of organ mimicry by orchestrating the generation of functional tissues through the regulation of cell functions and proliferation. Consequently, this technology has facilitated the creation of disease on-a-chip and singular organ on-a-chip models, featuring organ and organ mimicry closely resembling real organs. The majority of research on T2D on-a-chip has concentrated on individual organs like the AT to induce an inflammatory response or pancreas to replicate insulin secretion. However, existing single organ related-in vitro models face limitations in faithfully reproducing the complex micro pathophysiological of T2D, where pathophysiology involves multi-organs. These models are able to simulate specific aspects of T2D pathology, offering a partial representation. Furthermore, there are only a limited number of models that concurrently integrate a damaged glucose metabolism and inflammatory response to investigate T2D complications. Consequently, there is a compelling need to advance the creation of a multiple-organ on-a-chip capable of depicting the diverse biological interplays inherent in T2D pathophysiology, encompassing both inflammatory responses and damaged glucose metabolism. In this research, we engineered a multiple-organ on-a-chip model to replicate T2D pathophysiology using 3D cell-printing, running as a unified perfusion system. This T2D on-a-chip comprises liver, vAT, and pancreas compartments, with bioinks obtained from each organ to recreate their explicit microenvironments. The manufactured chip incorporates various pathological features observed in T2D patients. Notably, it was verified that hyperglycemia led to glucose metabolism disorders, the interaction between vAT and macrophages induced inflammation, and ultimately, disruptions occurred in the insulin signaling pathway. Additionally, the model simulated retinal complications, affirming its relevance for studying T2D-related complications. Finally, the precision of pharmaceutical reactions on the T2D on-a-chip was validated via a drug test specifically designed for T2D. These findings underscore the significant potential of developed multiple-organ on-a-chip as a high-level in vitro model. It effectively reproduces the intricate biological communication among multiple organs, offering a comprehensive understanding of the pathophysiology of T2D.