[Isolation, purification, and functional evaluation of human pancreatic islet].
OBJECTIVE
To isolate and purify human islet according to the method established by Ricordi and to evaluate the function and safety of these isolated human islets.


METHODS
Six pancreases were obtained from human corpses. The islets were isolated by liberase digestion and purificated by Ficoll density gradient centrifugation. The numbers, purity and vitality of the islets were analyzed. The various endocrine cell composition and distribution of the islets were checked by immunofluorescence staining. The glucose-induced insulin secretion was detected by chemiluminescence method. The isolated islets were transplanted under the left renal capsules of 10 streptozocin-induced diabetic nude mice. Twenty days later the left kidneys with transplanted islets of 2 mice with normal blood sugar were resected, and then blood sugar level was observed. An isolated human islet was suspended in RPMI-1066 culture medium for 72 h, then culture of pathogenic micro-organisms, endotoxin and procoagulant activity were detected so as to evaluate the security of the islet products.


RESULTS
The mean number of the isolated islets was (229 000 +/- 31 000) islet equivalents (IEQs)/pancreas or (4970 +/- 1620) IEQs/g pancreatic tissue, the mean purity was (59.0 +/- 8.9)%, and the mean vitality was (89 +/- 3)% for the purified islets. Immunofluorescence staining showed that there were 4 types of endocrine cells normally distributed in the islets. The mean insulin stimulation index was 8.1 +/- 4.0 (3.8 - 10.2). The glycemia found in the diabetic nude mice decreased to normal levels from the third day after islet transplantation and maintained normal for over 30 days. The parameters of security in these islet products were under the standard scope.


CONCLUSIONS
Human islets obtained according to Ricordi's method reach the standard for clinical islet transplantation in number, purity, vitality, function, and security.
Cai
Han-Qing
HQ
Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing 100029, China.
Xu
Shi-Qing
SQ
Men
Xiu-Li
XL
Sui
Wei-Guo
WG
Zhang
Wen-Jian
WJ
Li
Qi-Dong
QD
Yang
Wen-Ying
WY
Lou
Jin-Ning
JN
D000818:Animals; D018929:Cell Culture Techniques; D002469:Cell Separation / Q000379:methods*; D003921:Diabetes Mellitus, Experimental / Q000601:surgery; D006801:Humans; D007515:Islets of Langerhans / Q000166:cytology*; D016381:Islets of Langerhans Transplantation; D008297:Male; D051379:Mice; D008819:Mice, Nude