Investigation of insulin resistance through a multiorgan microfluidic organ-on-chip.

The development of hepatic insulin resistance (IR) is a critical factor in developing type 2 diabetes (T2D), where insulin fails to inhibit hepatic glucose production but retains its capacity to promote hepatic de novo lipogenesis leading to hyperglycemia and hypertriglyceridemia. Improving insulin sensitivity can be effective in preventing and treating T2D. However, selective control of glucose and lipid synthesis has been difficult. It is known that excess white adipose tissue is detrimental to insulin sensitivity, whereas brown adipose tissue transplantation can restore it in diabetic mice. However, challenges remain in our understanding of liver-adipose communication because the confounding effects of hypothalamic regulation of metabolic function cannot be ruled out in previous studies. There is a lack of in vitro models that use primary cells to study cellular-crosstalk under insulin resistant conditions. Building upon our previous work on the microfluidic primary liver and adipose organ-on-chips, we report for the first time, the development of an integrated insulin resistant liver-adipose (white and brown) organ-on-chip. The design of the microfluidic device was carried out using computational fluid dynamics; the experimental studies were conducted by carrying out detailed biochemical analysis RNA-seq analysis on both cell types. Further, we tested the hypothesis that brown adipocytes (BAC) regulated both hepatic insulin sensitivity and de novo lipogenesis. Our results show that BAC effectively restored insulin sensitivity and supressed hepatic glucose production and de novo lipogenesis suggesting that the experimental platform could be useful for identifying potential therapeutics to treat IR and diabetes.