| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 4345816 | Neuroscience Letters | 2010 | 4 Pages |
The lack of simple, non-invasive tests for a sub-clinical decline in insulin production hampers detection of early-stage type 1 pre-diabetes. Pressure pain withdrawal threshold (PPT) is a sensitive index of insulinopenia in diabetic and ‘pre-diabetic’ rats, but its ability to detect human insulin insufficiency is not known; if predictive, PPT testing of those at risk for diabetes would be warranted. To address this question, we used meta-analyses to demonstrate (i) a similar relationship between blood glucose and insulin levels in humans and diabetic rats and (ii) the predictive value of PPT for insulinopenia in a composite group (n = 53) of control, streptozotocin (STZ)-diabetic (STZ-HG), and normoglycemic (STZ-NG) rats. The frequency distributions of pooled insulin levels (ng/ml) consisted of three sub-populations, with peak values of <0.5, 1.5 ± 0.05, and 3.2 ± 0.04. Using the 2.3rd percentile of the sub-population with the highest insulin level (2.81 ng/ml) as a cut-off to define insulinopenia, 40 animals (98% of STZ and 25% of controls) were identified with compromised insulin production. The frequency distribution of pooled PPT values also consisted of three sub-populations (peaks at 75.9 ± 0.6 g, 97 ± 0.3 g and 122 ± 0.8 g), and when 106 g (the 2.3rd percentile of the most pressure-tolerant sub-population) was used as a cut-off, PPT measurements identified 92% of STZ-injected rats and 83% of rats with insulinopenia, as defined by 2.81 ng/ml insulin cut-off. Assuming similar between-species pain mechanisms, these findings support the potential usefulness of PPT measurements for detection of early-stage human type 1 diabetes.
