Independent anti-inflammatory effect of insulin in newly diagnosed type 2 diabetes.
BACKGROUND
Although insulin has been reported to have an anti-inflammatory effect, whether this effect is independent of its property to reduce blood glucose with insulin treatment in type 2 diabetes has not been investigated in detail. The purpose of this study was to evaluate the independent anti-inflammatory effect of insulin in patients with newly diagnosed type 2 diabetes.


METHODS
An 8-week, randomized, parallel-group study that enrolled 90 patients with newly diagnosed type 2 diabetes, who were randomly assigned to receive either insulin or metformin, was carried out. The doses of insulin and metformin were titrated according to fasting plasma glucose (FPG) and postprandial plasma glucose (PPG) during the 4 weeks; the target of FPG was 126 mg/dL and that of PPG was 160 mg/dL. The blood glucose levels were kept stabilized till the end of the study. The serum concentrations of high-sensitive C-reactive protein (hsCRP) and interleukin (IL)-6 were measured before starting the study and 4 and 8 weeks after initiation of insulin or metformin therapy.


RESULTS
After 4 weeks of dose titration, the levels of FPG were reduced in the two groups compared to baseline (p < 0.001), but there was no significant difference between the two groups (p > 0.05). During the next 4 weeks' treatment, the levels of FPG were stable, but the serum concentration of hsCRP and IL-6 was markedly reduced in the insulin-treated group compared with that in the metformin-treated group (p < 0.001).


CONCLUSIONS
Our data suggest that insulin has an anti-inflammatory effect that is independent of the reduction it causes in blood glucose.
Mao
Xiao-Ming
XM
Department of Endocrinology, Nanjing First Hospital, Nanjing Medical University, Jiangsu, China. maoxiaoming@medmail.com.cn
Liu
Hao
H
Tao
Xiao-Jun
XJ
Yin
Guo-Ping
GP
Li
Qian
Q
Wang
Shu-Kui
SK
D000328:Adult; D000368:Aged; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use*; D001786:Blood Glucose / Q000187:drug effects; D002097:C-Reactive Protein / Q000032:analysis*; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy / Q000276:immunology* / Q000378:metabolism; D005260:Female; D006801:Humans; D007004:Hypoglycemic Agents / Q000276:immunology / Q000627:therapeutic use*; D007328:Insulin / Q000276:immunology / Q000627:therapeutic use*; D015850:Interleukin-6 / Q000097:blood*; D008297:Male; D008687:Metformin / Q000627:therapeutic use; D008875:Middle Aged; D018709:Statistics, Nonparametric
D000893:Anti-Inflammatory Agents; D001786:Blood Glucose; D007004:Hypoglycemic Agents; D007328:Insulin; D015850:Interleukin-6; D002097:C-Reactive Protein; D008687:Metformin