Secretory unit of islet transplant objects (SUITO) index can predict outcome of intravenous glucose tolerance test.
BACKGROUND
Simple monitoring of engrafted islet function is important for follow-up of recipients after islet transplantation. We previously developed a simple assessment tool for islet graft function; the secretory unit of islet transplant objects (SUITO) index. The aim of this study was to clarify the relationship between the SUITO index and the outcomes of intravenous glucose tolerance tests (IVGTT).


METHODS
Fifteen series of blood samples from 6 islet recipients were collected before 3, 5, 10, 20, and 30 minutes after injection of 0.5 g/kg 50% dextrose. The SUITO index was calculated using plasma C-peptide and glucose level at fasting baseline. Samples were divided into the following 3 groups; low-SUITO (SUITO index <10; n = 3); middle-SUITO (SUITO index > or =10 to <26; n = 4); and high-SUITO (SUITO index > or =26; n = 8).


RESULTS
A threshold SUITO index of 26 showed good sensitivity (85.7%) and specificity (75.0%) to predict a blood glucose level of >10 mmol/L at 30 minutes. Blood glucose levels in the low-SUITO group were significantly higher than among the other 2 groups at baseline and 10, 20 and 30 minutes (P < .05). Glucose-level areas under the receiver-operating characteristic curve during IVGTT in the low-SUITO group were also significantly larger than among the other 2 groups (P < .05).


CONCLUSIONS
The SUITO index, using only a fasting blood sample, predicted IVGTT outcomes.
Takita
M
M
Baylor All Saints, Islet Cell Laboratory, Fort Worth, Dallas, Texas 76104, USA.
Matsumoto
S
S
Noguchi
H
H
Shimoda
M
M
Chujo
D
D
Itoh
T
T
Sugimoto
K
K
Tamura
Y
Y
Olsen
G S
GS
Naziruddin
B
B
Onaca
N
N
Levy
M F
MF
D001786:Blood Glucose / Q000378:metabolism*; D002096:C-Peptide / Q000097:blood; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000601:surgery*; D004784:Environmental Monitoring / Q000379:methods; D005215:Fasting; D005951:Glucose Tolerance Test; D006801:Humans; D016381:Islets of Langerhans Transplantation / Q000502:physiology*; D012372:ROC Curve; D012680:Sensitivity and Specificity
D001786:Blood Glucose; D002096:C-Peptide