Endocrine Abstracts

JOINT1398

Background: Lipodystrophies are a group of rare disorders characterised by loss of subcutaneous adipose tissue with alterations in its function and distribution. From a clinical viewpoint, an early onset of severe insulin resistance, cardiovascular diseases and neuromuscular abnormalities have been documented. To date, neuromuscular manifestations of lipodystrophy are under-investigated. The aim of this study was to investigate muscle ultrasound (US) alterations in a cohort of patients with lipodystrophy and their association with metabolic characteristics. This report presents preliminary results after the initial patients’ recruitment.

Methods: This is a monocentric prospective cohort study. Patients underwent muscle US (bilateral brachial biceps and rectus femoris) with the evaluation of the following variables for each muscle group: thickness, cross-sectional area (CSA), US-pattern and echogenicity assessed using Heckmatt scale (1, normal muscle; 2, increase in muscle echogenicity with normal bone echo; 3, moderate increase in muscle echogenicity with decreased bone echo; 4, severe increase in muscle echogenicity with shadowing obscuring the underlying bone echo). For each patient, clinical, metabolic and muscle functional parameters, and cutaneous Advanced Glycation End products (AGEs) were also evaluated.

Results: Five patients with familial partial lipodystrophy (FPLD) (3 patients with type 1 FPLD and 2 patients with LMNA-associated type 2 FPLD) and one patient with congenital generalized lipodystrophy (CGL) were currently included (M/F 1/5; median age 54, IQR 45-62 years; BMI 22, IQR 21-27). Muscle hypotrophy was found only in the patient with CGL, while a condition of normo/pseudohypertrophy was detected in the remaining patients. According to the Heckmatt scale, all patients presented an increased muscle echogenicity (3 patients with score 2 and 3 patients with score 3). Two main different US-patterns have been recognized: A) homogenously increased echogenicity of the entire muscle with partial loss of architectural features, compatible with muscle fibrosis and steatosis (4 patients); B) focal areas of markedly increased echogenicity, oftentimes obscuring bone echo, that could suggest fibrosis with associated inflammation (2 patients). Patients with higher muscle echogenicity (Heckmatt score 3) had higher BMI, fat mass, HbA1c, triglycerides levels and AGEs than subjects with lower muscle echogenicity (Heckmatt score 2). Further, US-pattern B was associated with higher AGEs, suggesting that muscle inflammatory US pattern could reflect systemic inflammation.

Conclusions: Lipodystrophy is associated with specific muscle US alterations that reflects a condition of muscle fibrosis/steatosis, sometimes accompanied by inflammation. These alterations could reflect metabolic dysregulation and systemic inflammation, thus representing an indirect marker of increased cardiovascular risk.