Fluoxetine Essay in Children With Autism

Autism is a severe neurodevelopmental disorder characterized by impaired social interaction and communication, and by a markedly restricted repertoire of activities and interests. The population prevalence of autism is approximately 1 in 1000 (GILLBERG and WING, 1999) and the ratio of affected males to females is 4:1 (FOMBONNE, 1999). Although typically considered a childhood disorder, most persons with autism experience marked functional impairment throughout their lives. Follow-up studies of children with autism show that only 5%-10% become independent as adults, 25% progress but still require supervision, and the remaining continue to be severely impaired and in need of institutionalized care (WING, 1989). Thus, the syndrome represents a substantial public health problem with tragic cost to the individual, the family, and the community.

It is a randomized, double blind flexible dose study with parallel groups, controlled, fluoxetine versus placebo.

The final efficacy evaluation will be done after 6 months of treatment; Nine obligatory visits are planned Patients will be assessed at the following visits: base-line inclusion (D-15), and 2, 4, ,12, ,20, 22, 24 25, 26 weeks. At the 24 W visit, the final efficacy will be performed and medication will be tapered over a maximum period of 2 weeks. The final safety assessment will be performed at 26W.

BRAIN IMAGING PROTOCOL :

We will assess the resting state regional cerebral blood flow (rCBF) in autistic children using labeled water and PET, as it is still the most reliable and least invasive method. In addition, an anatomical and functional MRI will be performed in all children, the same day. Brain imaging studies will be performed at the Service HOSPITALIER Frederic JOLIOT (ORSAY, France) under Dr Monica ZILBOVICIUS responsibility.

Each brain imaging examination will be performed twice: 1) at time zero (T0) - before the beginning of the treatment and 2) six month later, after placebo or sertraline treatment.

Functional imaging in the resting state - Positron emission tomography :

Regional cerebral blood flow (rCBF) will be measured on a Siemens ECAT HR+ camera. Attenuation-corrected data are reconstructed into 63 slices, with a resulting resolution of 4.5 mm full-width-at-half-maximum. Fifteen seconds before each scan, 7 mCi of H215O is administrated by bolus injection. Data are collected during 80 s. All rCBF examinations will be performed at rest during sleep induced by premedication (4 mg/kg of pentobarbital). We have previously reported that this premedication has no effects on absolute rCBF values and regional distribution.

Anatomical MRI:

A high resolution MRI of the brain will be obtained in all children witg a 1.5 Tesla Signa General Electric scanner using a 3D T1-weighted FSPGR sequence (TR/TE/TI/NEX: 10.5/2.2/600/1, flip angle 10°, matrix size 256 x 192, yielding 124 axial slices and a thickness of 1.2 mm, field of view 22 cm). The acquisition duration is 6 minutes. In addition, FLAIR and T2 axial and coronal sequences will be also acquired.

Biological measures:

Blood sample procedure for whole blood serotonin: patients must follow a diet poor in tryptophan during two days before the blood sampling. Blood sample will be performed without premedication between nine and 11 AM. Blood will be withdrawn into tubes containing EDTA acid and aprotinin. Platelet- poor plasma (containing up to 0.1% of the original platelet count as assessed by contrast phase microscopy) is obtained within 2 hours by centrifugation (2000g, 4C, 15 mn) and frozen as 0.5mL aliquots at -80C until assess (blind procedures will be used). The whole blood content will by measured by radio-enzymology.