Polymyxin B, scavenger of endotoxin, enhances isolation yield and in vivo function of islets.
Collagenase purified from bacteria has been used to isolate islets for transplantation. However, collagenase is contaminated with small amounts of endotoxin, which induces dysfunction or apoptosis of islets. In this study, we investigated the effects of polymyxin B, endotoxin scavenger, on the yield and quality of isolated islets. It is revealed that polymyxin B neutralized endotoxin in vitro and inhibited endotoxin-mediated decreases of the glucose stimulation index. Additionally, adenosine triphosphate (ATP) quantitation, islet regression assay, and caspase-3 activation assay demonstrated that polymyxin B efficiently blocked the toxic effects induced by endotoxin. Thereafter, we isolated mouse islets both with and without polymyxin B and compared total islet equivalents (IEQs), glucose-stimulated insulin release, and ATP content. Polymyxin B enhanced islet recovery, and ATP content of islets, and glucose stimulation index, and reduced TNF-alpha expression of islets. Marginal transplantation (200 IEQs/mouse) under the kidney capsule of diabetic mice induced normoglycemia in 30% of the polymyxin B group, but not in any mouse of control group. This result suggests that islets isolated with polymyxin B more effectively lower blood glucose levels as compared with control islets. Thus, polymyxin B could serve as a useful agent in the protection of islets from endotoxin-induced inflammation and apoptosis.
Park
Sang G
SG
Department of Biomedical Science, CHA University, Yeoksam-dong, Kangnam-gu, Seoul, Korea. sgpark@cha.ac.kr
Kim
Jae H
JH
Oh
Ji H
JH
Lee
Han N
HN
Park
Ho S
HS
Chung
Sung S
SS
Lee
Ye J
YJ
Lee
Yeon Y
YY
Jung
Hye S
HS
Park
Kyong S
KS
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001483:Base Sequence; D001786:Blood Glucose / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000235:genetics / Q000503:physiopathology / Q000601:surgery; D004731:Endotoxins / Q000037:antagonists & inhibitors* / Q000633:toxicity; D066298:In Vitro Techniques; D007249:Inflammation / Q000517:prevention & control; D007328:Insulin / Q000378:metabolism; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D016381:Islets of Langerhans Transplantation / Q000379:methods* / Q000473:pathology / Q000502:physiology; D008070:Lipopolysaccharides / Q000037:antagonists & inhibitors / Q000633:toxicity; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D011112:Polymyxin B / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014185:Transplantation, Isogeneic; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics
D001786:Blood Glucose; D004731:Endotoxins; D007328:Insulin; D008070:Lipopolysaccharides; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D011112:Polymyxin B