In this work, sodium percarbonate and calcium peroxide were utilized as an oxygen source to improve islet viability and functionality.

Objective Our study aim was to determine encapsulated islet graft viability in an omentum pouch and the effect of fibroblast growth factor 1 (FGF-1) released from our redesigned alginate microcapsules on the function of the graft. Methods Isolated rat islets were encapsulated in an inner core made with 1.5% low-viscosity–high-mannuronic-acid alginate followed by an external layer made with 1.25% low-viscosity high-guluronic acid alginate with or without FGF-1, in microcapsules measuring 300 to 400 µm in diameter. The 2 alginate layers were separated by a perm-selective membrane made with 0.1% poly-l-ornithine, and the inner low-viscosity–high-mannuronic-acid core was partially chelated using 55 mM sodium citrate for 2 minutes. Results A marginal mass of encapsulated islet allografts (∼2000 islets/kg) in streptozotocin-diabetic Lewis rats caused significant reduction in blood glucose levels similar to the effect observed with encapsulated islet isografts. Transplantation of alloislets coencapsulated with FGF-1 did not result in better glycemic control, but induced greater body weight maintenance in transplant recipients compared with those that received only alloislets. Histological examination of the retrieved tissue demonstrated morphologically and functionally intact islets in the microcapsules, with no signs of fibrosis. Conclusions We conclude that the omentum is a viable site for encapsulated islet transplantation.

Safe clinical hormone replacement (HR) will likely become increasingly important in the growing populations of aged women and cancer patients undergoing treatments that ablate the ovaries. Cell-based HRT (cHRT) is an alternative approach that may allow certain physiological outcomes to be achieved with lower circulating hormone levels than pharmacological means due to participation of cells in the hypothalamus-pituitary-ovary feedback control loop. Here we describe the in vivo performance of 3D bioengineered ovarian constructs that recapitulate native cell–cell interactions between ovarian granulosa and theca cells as an approach to cHRT. The constructs are fabricated using either Ca⁺⁺ or Sr⁺⁺ to crosslink alginate. Following implantation in ovariectomized (ovx) rats, the Sr⁺⁺-cross-linked constructs achieve stable secretion of hormones during 90 days of study. Further, we show these constructs with isogeneic cells to be effective in ameliorating adverse effects of hormone deficiency, including bone health, uterine health, and body composition in this rat model.