PSUN12 Change of Computed Tomography-Based Body Composition After Adrenalectomy in Patients with Pheochromocytoma: Importance of Sympathetic Activity on Human Fat Metabolism

CONTEXT: Despite potential biological importance of sympathetic nervous system on fat and skeletal muscle metabolism in animal and in vitro experiments, its impact in humans remains questionable. OBJECTIVE: To clarify the influence of catecholamine excess on human body composition DESIGN: Retrospective longitudinal cohort study PATIENTS: 313 consecutive patients with histologically confirmed pheochromocytoma who underwent repeat abdomen computed tomography (CT) scans before and after adrenalectomy were included. Measurements: Changes in CT-determined visceral fat area (VFA), subcutaneous fat area (SFA), skeletal muscle area (SMA), and skeletal muscle index (SMI) measured at the level of third lumbar vertebra RESULTS: The mean age was 50.6X ± 13.6 years and 171 (54.6%) were women. A median follow-up duration of repeat CT was 25.0 months. VFA and SFA were 14.5% and 15.8% higher, respectively, after adrenalectomy, whereas SMA and SMI remain unchanged. Consistently, patients with visceral obesity significantly increased from 103 (32.9%) at baseline to 138 (44.1%) following surgery; however, the prevalence of sarcopenia was equivalent. Furthermore, higher baseline levels of blood metanephrine and urine normetanephrine were related to greater increases in SFA, but not in muscle parameters, after adrenalectomy. CONCLUSION: This study provides important clinical evidence that sympathetic hyperactivity can contribute to lipolysis in both visceral and subcutaneous adipose tissues, while its impact on human skeletal muscle is less clear. Presentation: Sunday, June 12, 2022 12:30 p.m. - 2:30 p.m.