Effect of Etanercept Concentration on Human Islet Integrity.

BACKGROUND: Etanercept is widely used as an antiinflammatory drug to improve engraftment after intraportal islet transplantation. In contrast to other immunosuppressive agents, very little is known about detrimental effects of etanercept on islets. The aim of this pilot study was to define the toxic range of etanercept. METHODS: Human islets isolated from 8 donors were cultured for 4-5 days at 37°C in culture medium supplemented with etanercept at concentrations from 2.5 to 40 µg/mL, corresponding to potential in vivo levels within the portal vein. After culture, islet equivalent (IEQ) yield, fragmentation index (islet number/IEQ), purity, viability, and stimulated insulin release (2 vs 20 mmol/L) were assessed and normalized to islets before culture. RESULTS: Yield (73 ± 8%) and viability (91 ± 4%) were highest with 5 µg/mL etanercept. Islet loss was evident when etanercept was ≥10 µg/mL (55 ± 7%; P < .05 vs control). Fragmentation (154 ± 34%; P < .05) was markedly increased and viability (81 ± 4%, P < .05) markedly decreased with etanercept >10 µg/mL. The accumulation of cell debris at concentrations ≥20 µg/mL resulted in a significant reduction of islet purity (84 ± 3%; P < .05). Etanercept did not interfere with stimulated insulin secretion at concentrations ≤10 µg/mL. The maximum stimulation index was noted at 2.5 µg/mL (1.8 ± 0.1). CONCLUSIONS: Etanercept is tolerated by isolated human islets at concentrations <10 µg/mL. Our data suggest that the tight range between benefit and toxicity should be considered for dosage and administration of etanercept.

Hypoxia-Induced Damage in Human Islets Is Reduced With the Use of Mesenchymal Stem Cell-Preconditioned Medium.

BACKGROUND: Mesenchymal stem cells (MSCs) are protective for islets when cotransplanted in a hypoxic environment. However, the risk of neoplasia is increased when MSCs are transplanted into immunosuppressed patients. This initial study aimed to investigate whether the production of protective factors from MSC can be stimulated by different culture conditions to benefit human islets cultured in hypoxia. METHODS: MSC were isolated from human adipose tissue and cultured for 2 days in supplemented Minimum Essential Media α (MEMα) and 21% (21%-MEMα) or 1% oxygen (1%-MEMα). Native MEMα served as control. After MSC harvesting, cell-depleted media were frozen at -20°C until use for human islet culture in 2% oxygen for 72-96 hours before islet characterization. Data were normalized to control islets cultured in native MEMα and 2% oxygen (mean ± SEM). RESULTS: After culture in 21%- or 1%-MEMα, islet recovery increased to 117 ± 12% (NS) and 138 ± 12% (P < .05), respectively. Viability did not change after culture in native MEMα (59 ± 2%), 21%-MEMα (59 ± 3%), or 1%-MEMα (61 ± 3%). Compared with control samples, the glucose stimulation index was increased after culture in 21%-MEMα (P < .05) or 1%-MEMα (P < .05). Overall survival was higher in 1%-MEMα (143 ± 14%) than in 21%-MEMα (119 ± 14%; NS) or native MEMα (P < .05). CONCLUSIONS: This study demonstrates that MSC-preconditioned MEMα increases survival and in vitro function of hypoxic human islets. These findings indicate that hypoxic MSCs seem to produce factors that improve survival of islets suffering from hypoxia.

Developing practice in cancer rehabilitation.

This module explores the concept of rehabilitation and supportive care in a cancer context. It examines policy and practice that inform rehabilitation in cancer care in England and considers how rehabilitation and supportive care issues can be addressed in clinical practice.