# Differential stress responses of immunoisolated human islets embedded in pancreatic extracellular matrix under static and free-fall dynamic conditions

## TL;DR

This study shows that culturing human pancreatic islets in a dynamic, low-shear environment with extracellular matrix improves their survival and function under stress.

## Contribution

The study introduces a novel combination of dynamic culture and ECM enrichment to enhance islet resilience during ex vivo conditions.

## Key findings

- Dynamic culture improved islet viability and glucose responsiveness under ER-stress.
- ECM-containing capsules reduced inflammatory markers and supported adaptive matrix remodeling.
- Combining dynamic culture with ECM significantly reduced cell death and improved stress adaptation.

## Abstract

Pancreatic islet transplantation offers great promise for the treatment of type 1 diabetes, yet the functional decline of islets after isolation remains a major obstacle. Increasing evidence highlights the endoplasmic reticulum (ER) as a critical regulator of islet cell survival under stress. We explored how ex vivo culture conditions affect encapsulated islet resilience under ER-stress. Two conditions were assessed: (i) incorporation of decellularized porcine pancreatic extracellular matrix (ECM) into alginate microcapsules, and (ii) free-fall dynamic pre-conditioning culture. Human islets were encapsulated in alginate with or without ECM, cultured under static or dynamic conditions, and exposed to acute ER-stress followed or not by a recovery period. Dynamic culture preserved viability and enhanced glucose responsiveness. ECM-containing capsules showed reduced inflammatory marker expression, while encapsulation in alginate-only capsules led to more pronounced changes associated with ECM remodeling. Under ER-stress, the dynamic culture, especially combined with ECM, maintained cell function and reduced cell death. Gene profiles indicated improved stress adaptation and ECM remodeling. These results highlight ECM enrichment and dynamic culture as good strategies to maintain islet survival and functionality.

Graphical AbstractEncapsulated human pancreatic islets were cultured in a free-fall dynamic system that simulates a low-shear environment, enhancing nutrient and oxygen exchange. Upon exposure to endoplasmic reticulum (ER)-stress, dynamic culture promoted a protective and adaptive cellular response, either in alginate-only or in extracellular matrix (ECM)-containing microcapsules. Dynamic culture enhanced insulin secretion, indicating improved β-cell glucose responsiveness. It reduced the expression of inflammatory chemokines, particularly CXCL1, suggesting lower immunogenic signaling. Contributed to reduced cell death, reflecting enhanced islet viability and survival. Additionally, matrix remodeling activity was elevated, as shown by increased MMP2 and MMP9 expression, indicating an adaptive extracellular matrix turnover. Created in BioRender. Silva, I. (2025) https://BioRender.com/nf8b3yv

Encapsulated human pancreatic islets were cultured in a free-fall dynamic system that simulates a low-shear environment, enhancing nutrient and oxygen exchange. Upon exposure to endoplasmic reticulum (ER)-stress, dynamic culture promoted a protective and adaptive cellular response, either in alginate-only or in extracellular matrix (ECM)-containing microcapsules. Dynamic culture enhanced insulin secretion, indicating improved β-cell glucose responsiveness. It reduced the expression of inflammatory chemokines, particularly CXCL1, suggesting lower immunogenic signaling. Contributed to reduced cell death, reflecting enhanced islet viability and survival. Additionally, matrix remodeling activity was elevated, as shown by increased MMP2 and MMP9 expression, indicating an adaptive extracellular matrix turnover. Created in BioRender. Silva, I. (2025) https://BioRender.com/nf8b3yv