Anti-proinflammatory effects of sirolimus on human islet preparations.
BACKGROUND
Sirolimus plays a critical role in facilitating steroid-free immunosuppression, in conjunction with low dose tacrolimus, in current islet transplantation. Although several studies have investigated the effects of sirolimus on islet cells, conflicting results have been reported. In this study, we assessed the effects of sirolimus supplementation in culture media on human islet preparations, focusing on the anti-proinflammatory aspects.


METHODS
Human islet preparations were divided into four groups: pure (purity >90%) sirolimus (30 ng/mL); pure control (0 ng/mL); impure (purity 40%-60%) sirolimus; and impure control. All groups were cultured for 3 days and assessed regarding glucose stimulated insulin release, fractional beta-cell viability, beta-cell, and macrophage content. Cytokine and chemokine production from islet preparations and sorted pancreatic ductal cells were also examined.


RESULTS
Stimulated insulin release in the impure sirolimus group was significantly increased (P=0.024), as previously reported. Although fractional beta-cell viability showed no significant differences, beta-cell survival during culture significantly increased in impure sirolimus group when compared with the impure control group (P=0.015). Tumor necrosis factor-alpha, interleukin-1beta, monocyte chemotactic protein-1, and macrophage inflammatory protein-1beta production from the impure sirolimus group significantly decreased (P<0.05). Furthermore, tumor necrosis factor-alpha and macrophage inflammatory protein-1beta production from sorted ductal cells significantly decreased in the sirolimus group (P<0.05). The number of macrophages contained in islet preparations significantly decreased in the impure sirolimus group when compared with the impure control group (P<0.05).


CONCLUSIONS
Sirolimus improved not only stimulated insulin release, but also beta-cell survival during culture. The antiinflammatory effects of sirolimus also appear beneficial to islet cells in culture and may be a useful strategy in improving islet transplantation outcomes.
Mita
Atsuyoshi
A
Cell Transplant Center, Diabetes Research Institute, Miami, FL, USA.
Ricordi
Camillo
C
Miki
Atsushi
A
Barker
Scott
S
Haertter
Ross
R
Hashikura
Yasuhiko
Y
Miyagawa
Shin-Ichi
S
Burke
George W
GW
Inverardi
Luca
L
Ichii
Hirohito
H
D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D002470:Cell Survival; D018932:Chemokine CCL2 / Q000378:metabolism; D054407:Chemokine CCL4 / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D006801:Humans; D007166:Immunosuppressive Agents / Q000494:pharmacology*; D018836:Inflammation Mediators / Q000378:metabolism*; D007328:Insulin / Q000378:metabolism; D050417:Insulin-Secreting Cells / Q000187:drug effects / Q000378:metabolism; D053583:Interleukin-1beta / Q000378:metabolism; D007515:Islets of Langerhans / Q000187:drug effects* / Q000378:metabolism; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism; D010183:Pancreatic Ducts / Q000187:drug effects / Q000378:metabolism; D020123:Sirolimus / Q000494:pharmacology*; D013997:Time Factors; D046509:Tissue Culture Techniques; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D000893:Anti-Inflammatory Agents; C111835:CCL2 protein, human; C066507:CCL4 protein, human; D018932:Chemokine CCL2; D054407:Chemokine CCL4; D007166:Immunosuppressive Agents; D018836:Inflammation Mediators; D007328:Insulin; D053583:Interleukin-1beta; D014409:Tumor Necrosis Factor-alpha; D005947:Glucose; D020123:Sirolimus