Severe insulin resistance contrasting with mild anthropometric changes in the adipose tissue of HIV-infected children with lipohypertrophy.

BACKGROUND

The HIV-associated lipodystrophic syndrome (HIV-LDS) combines redistribution of fat mass with insulin resistance and hyperlipidemia. We have previously reported that HIV-LDS prevails in children in a comparable pattern as in adults. The metabolic activity itself of the lipodystrophic adipose tissue in HIV infection has been poorly studied.

AIM AND

METHODS

To assess in situ the insulin sensitivity of the lipohypertrophic subcutaneous abdominal adipose tissue using the microdialysis technique in HIV-infected children. Insulin sensitivity, assessed by the inhibition of glycerol release, was measured in the abdominal subcutaneous adipose tissue during a standard oral glucose tolerance test (OGTT) in six HIV-infected children under multi-therapy with abdominal lipohypertrophy (supra-iliac skinfold thickness >97th percentile) (HIV/LH+), in six obese children (obese group) and in eight HIV-infected children without lipodystrophy (HIV/LH-).

RESULTS

Glucose tolerance was normal in all subjects. Mean insulin areas under the curve (IAUC) were significantly higher in the obese and HIV/LH+ groups than in HIV/LH- (8769+/-5429, 8161+/-4552 and 3618+/-2222 mU min l(-1), respectively; P=0.04 for the three groups comparison by the Kruskal-Wallis test), reflecting insulin resistance in the two former groups independent of a significant difference in percentage fat mass (37.2+/-4.7, 22.8+/-10.9 and 20.7+/-7.1%, respectively; P= 0.006). The crude inhibition of glycerol release, expressed as the relative change in dialysate glycerol concentration between baseline and 120 min, was not statistically different between the three groups (14% in obese, -38+/-14% in HIV/LH+ and -51+/-17% in HIV/LH- groups; P=0.3). The inhibition of glycerol release with respect to the circulating insulin level (expressed by IAUC) was similar in HIV/LH+ and obese groups (-6+/-5 x 10(-3) and -7+/-5 x 10(-3) l mU(-1) min(-1), respectively, P=0.4 for two-groups comparison by the U-Mann-Whitney test) and four-fold less than in the HIV/LH- group (-24+/-25 x 10(-3) l mU(-1) min(-1); P=0.02).

CONCLUSION

These data argue in favor of insulin resistance in the adipose tissue of lipohypertrophies associated with HIV infection.