Interictal ghrelin levels in adult patients with epilepsy

Purpose: In vitro or in animal models of epilepsy, ghrelin showed a clear anticonvulsant action, whose mechanisms are somewhat obscure. In humans however, a controversial relation exists between ghrelin and epilepsy. Yet most studies investigated just total ghrelin levels, without a proper distinction between acylated (AG) or unacylated ghrelin (UAG). We thus evaluated separately AG and UAG interictal levels in adult patients with epilepsy, and their relation to clinical features. Method: Cross-sectional study in a tertiary referral centre. Fifty-six patients were recruited: 19 with idiopathic generalized epilepsy, 18 with cryptogenic focal epilepsy and 19 with symptomatic focal epilepsy. Twenty-six healthy subjects of similar age, sex and body mass index (BMI) acted as controls. AG and UAG levels were measured following an overnight fasting and contrasted to the clinical and biometric features. Results: AG and UAG levels were similar between patients and controls. The AG/UAG ratio was higher in patients, also when weighted for covariates (age, BMI, gender, and drugs). Splitting patients according to their epileptic syndrome, drug-resistance or antiepileptic drug number/type resulted in no significant difference in AG, UAG or their ratio. Yet, AG and UAG levels were positively predicted by disease duration, independently by confounders. Conclusion: In adult patients with epilepsy, interictal ghrelin levels did not differ from controls, though the AG/UAG ratio was imbalanced. Interpretation of the latter phenomenon is uncertain. Further, levels of AG and UAG were in direct proportion to disease duration, which may represent a long-term compensatory mechanism, antagonistic to the epileptic process.