Lipodystrophy-like features after total body irradiation among survivors of childhood acute leukemia.

BACKGROUND/OBJECTIVE: The number of long-term survivors of childhood acute leukemia (AL) is substantially growing. These patients are at high risk for metabolic syndrome (MS), especially those who received total body irradiation (TBI). The consequences of children's irradiation on adipose tissue (AT) development in adulthood are currently unknown. The objective of this study is to assess the impact of TBI on AT of childhood AL survivors.

DESIGN: We compared the morphological and functional characteristics of AT among survivors of childhood AL who developed MS and received (n= 12) or not (n=12) TBI.

SUBJECTS/METHODS: Body fat distribution and ectopic fat stores (abdominal visceral and liver fat) were evaluated by DEXA, MRI and 1H-spectroscopy. Functional characteristics of subcutaneous AT were investigated by studying gene expression and pre-adipocyte differentiation in culture.

RESULTS: Patients who have received TBI exhibited a lower BMI (minus 5 kg/m²) and a lower waist circumference (minus 14 cm), especially irradiated women. Despite the lower quantity of intra-abdominal AT, irradiated patient displayed a nearly two-fold greater content of liver fat when compared to non-irradiated patient (17 vs. 9%, p=0.008). These lipodystrophic-like features are supplemented by molecular abnormalities in subcutaneous AT of irradiated patients: decrease of gene expression of SREBP1 (minus 39%, p=0.01) and CIDEA (minus 36%, p=0.004), and a clear alteration of pre-adipocyte differentiation.

CONCLUSIONS: These results strongly support the direct effect of irradiation on AT, especially in women, leading to specific non-alcoholic fatty liver disease, despite lower BMI. A long-term appropriate follow-up is necessary for these patients.