Original investigation
Does insulin resistance co-exist with glucocorticoid resistance in the metabolic syndrome? Studies comparing skin sensitivity to glucocorticoids in individuals with and without acanthosis nigricans
1 Department of Clinical Medical Sciences, The University of the West Indies. St Augustine, Trinidad & Tobago.W.I
2 Department of Pre-Clinical Medical Sciences, The University of The West Indies. St Augustine, Trinidad & Tobago.W.I
3 Department of Para-Clinical Medical Sciences, The University of the West Indies. St Augustine, Trinidad and Tobago.W.I
Cardiovascular Diabetology 2012, 11:31 doi:10.1186/1475-2840-11-31
Published: 30 March 2012Abstract
Background
The metabolic syndrome is associated with increased risk for both diabetes and coronary artery disease, which insulin resistance alone does not satisfactorily explain. We propose an additional and complementary underlying mechanism of glucocorticoid resistance.
Results
Using acanthosis nigricans (AN) and skin vasoconstrictor (SVC) response to topically applied beclomethasone dipropionate as markers of insulin and glucocorticoid resistance, respectively, we compared anthropometric, biochemical, pro-inflammatory markers and the SVC response in subjects with AN in two studies: STUDY 1 was used to compare subjects with AN (Grade 4, n = 32), with those without AN (n = 68) while STUDY 2 compared these responses among a cross-section of diabetic patients (n = 109) with varying grades of AN (grade 0, n = 30; grade 1, n = 24; grade 2, n = 18; grade 3, n = 25; grade 4, n = 12).
Findings
In both studies there was an inverse relationship between AN Grade 4 and the SVC response, (P < 0.001). In STUDY 1, AN Grade 4 was associated with age, waist circumference, BMI, fasting blood glucose, plasma lipids and hs-CRP (P < 0.05). SVC was an independent predictor of CRP and those with combined AN and a negative SVC response, CRP levels were highest. In Study 2 when the SVC response in subjects with type 2 diabetes mellitus with varying degrees of AN was studied, it showed that for any degree of AN, the SVC response is more likely to be negative and was independent of gender and ethnicity.
Conclusion
An absent SVC response represents a new biomarker for the metabolic syndrome and the exaggerated inflammatory response, which characterizes the metabolic syndrome, may be an outcome of deficient glucocorticoid action in vascular tissue.
