Endocrine Abstracts

Acquired lipodystrophies (AL) are syndromes characterized by an irreversible loss of subcutaneous adipose tissue and are conventionally distinct in partial (Barraquer-Simons) or generalized forms (Lawrence Syndrome) based on the pattern of adipose tissue disappearance. Alike to congenital forms, AL exhibit metabolic abnormalities that include insulin resistance, diabetes mellitus, hypertliglycerdidemia, reduced leptin levels, hepatomegaly and steatosis. While in most cases of congenital forms of lipodystrophy a genetic alteration can be identified, the pathogenic mechanism responsible for the acquired disease are unknown. Based on the evidence of increased association between AL and autoimmune disorders a reaction against yet-to-be identified white adipose tissue antigens is postulated but the association with autoimmune diseases is variable and any attempt of classification in this context is challenging. Barraquer-Simons syndrome has usually a milder metabolic derangement that may be associated with hypocomplementemia and presence of a ‘C3 nefritic factor’ auto-antibody, Lawrence syndrome is frequently characterized by the development of severe metabolic complications sometimes difficult to be controlled by standard medical therapies. Other forms of acquired lipodystrophy are iatrogenic. One example being AL secondary to combination anti-retroviral HIV drug treatment. These drugs affect the health of adipose tissue by different mechanisms: generating mitochondrial toxicity, increasing local inflammation, perturbing adipocyte differentiation or impairing hormonal production or signal transduction. Lipodystrophy may also develop after complex treatment related to bone marrow transplant occurring during childhood. Cytotoxic treatments primarily total body irradiation or graft-versus-host disease by taking place during a window of time very sensitive for the commitment of adipose stem cells may affect the normal development of fat mass causing later on lipodystrophy. Bone marrow transplant-induced lipodystrophy is frequently underestimated. Finally, even rarer forms of paraneoplastic, acquired lipodystrophies have been described.