ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Endocrine Abstracts (2008) 16 P550

Endocrine and metabolic alterations in narcoleptic patients as result of orexin-A reduction

Guido Dalmazi1, Francesca Poli2, Danilo Ribichini1, Flaminia Fanelli1, Valentina Vicennati1, Rosaria de Iasio1, Pasquale Montagna2, Renato Pasquali1, Giuseppe Plazzi2 & Uberto Pagotto1

1Endocrinology Unit, Department of Internal Medicine and Gastroenterology, and Center for Applied Biomedical Research S Orsola-Malpighi Hospital, Alma Mater Bologna University, Bologna, Italy; 2Department of Neurological Sciences, Alma Mater Bologna University, Bologna, Italy.

Aims: Narcolepsy with cataplexy (NC) is a rare, chronic disease, characterized by excessive daytime sleepiness, cataplexy, disrupted nocturnal sleep and manifestations of abnormal REM (Rapid Eye Movement) sleep. Human NC is probably caused by environmental and genetic factors, leading to dysfunctions in hypothalamic orexigenic neurons. Recent studies showed that NC was associated with an increase in Body Mass Index, despite a reduction in food intake. In the current study we investigated hormonal and metabolic patterns in patients with NC to determine whether an association between NC and hormonal and metabolic disorders may occur.

Methods: This was a case–control study approved by local Ethical Committee. We enrolled 23 patients with NC and two groups of control subjects, matched for age and BMI: in the first group we included 21 patients with other sleep disorders, while the second group composed by 19 patients was drawn from general population.

Results: In patients with NC we found a decrease in CSF orexin–A (NC=13 pg/ml, controls=109 pg/ml; P=0), and a statistical significant increase in BMI and waist circumference; in the same patients an increase in plasma leptin levels, total and LDL cholesterol, and oestradiol, and a reduction in HDL cholesterol and plasma cortisol were also detected. These alterations, however, were detected only in male group. Our results confirm that NC is a disease due to low CSF orexin–A levels, and it is associated not only with metabolic disorders, such as perturbations in lipid profile, leptin secretion and body fat distribution, but also with endocrine alterations, especially regarding cortisol and estradiol secretion.

Conclusions: Studies on narcolepsy may provide interesting clues about the peripheral role of orexin-A in modulating hormones and metabolic processes.