Metabolic Dysregulation in Adult Survivors of Pediatric Hematopoietic Stem Cell Transplantation: The Role of Incretins

CONTEXT: Survivors of pediatric hematopoietic stem cell transplantation (HSCT) have increased risk of developing metabolic syndrome (MetS), but the mechanisms are poorly understood.

OBJECTIVE: We aimed to test the hypothesis that insufficient secretion of glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) plays a pathogenetic role in HSCT survivors with MetS.

METHODS: This cross-sectional cohort study, conducted at the Danish national referral center for HSCT, studied 42 male HSCT survivors (median age 28.9 years) for a median 21.2 years from HSCT, along with 15 age- and sex-matched healthy controls. Main outcome measures were glucose metabolism and incretin hormones (by oral glucose tolerance test [OGTT]) and MetS criteria. The hypothesis was formulated before data collection.

RESULTS: GLP-1, GIP, and glucagon during an OGTT were similar in patients and controls, with no overall difference between survivors with (24%) and without MetS. However, fasting glucagon was significantly higher in patients with hypertriglyceridemia (mean difference [MD]: 6.1 pmol/L; 95% CI, 1.5-10.8; P = 0.01), and correlated with HDL (MD: 4.7 mmol/L; 95% CI, -0.6 to 9.9; P = 0.08), android-gynoid ratio (correlation coefficient [r] = 0.6, P = 0.0001) and waist-hip ratio (r = 0.5, P = 0.002). A similar pattern was seen for GIP, correlating positively with triglyceride (MD: 60%; 95% CI, 44-82; P = 0.002). GIP levels were significantly increased in patients treated with total body irradiation (TBI) (MD: 165%; 95% CI, 118-230; P = 0.004), which was found to be a significant risk factor for MetS.

CONCLUSION: This study demonstrates an altered production of incretin hormones in HSCT survivors previously treated with TBI, developing dyslipidemia and abdominal adiposity.