MMP-2, MMP-9, TNF-α levels in relation to subtypes of attention deficit hyperactivity disorder

Abstract

Many authors have suggested the association between Attention Deficit Hyperactivity Disorder (ADHD) and inflammation through various mechanisms among which increased serum cytokines. 30 newly diagnosed ADHD children, aged 6-12 and of both sexes were collected from outpatient clinic, Psychiatry Department, Al Zahraa University Hospital and a matched control group of 30 children. They were subjected to Clinical assessment, Whechsler Intelligence Scale for children (WISC), Conners' Parent Rating Scale-Revised & serum MMP-2, MMP-9, TNF-a levels were determined. There was statistical significant difference between patient and control groups regarding MMP-2 level (648.50 ± 81.94 vs 344.13 ± 32.02), MMP-9 level (143.00±16.98 vs 102.90 ± 4.13) & TNF-a level (345 ± 7.1.vs 202 ± 22.3). Hyperactive/ impulsive subtype represented 16(53.3%), Inattentive subtype represented 6(20%), Combined subtype represented 8(26.7%) of the ADHD group. MMP-2, MMP-9, TNF-a levels were all higher among the Hyperactive/impulsive subtype, followed by the combined subtype then the Inattentive subtype with high statistical significant difference. A high statistical significant difference was found in all subscales of Conners' scale among the 3 subtypes of ADHD. A positive correlation was found between TNF-a level and age, whereas, a negative correlation exists between MMP-2, MMP-9, TNF-a level and IQ. In addition, correlation was found between MMP-2, MMP-9 levels and cognitive problems, TNF-a level and inattention. Our study illustrates the co-occurrence of inflammatory process and ADHD, but further studies on larger sample are needed.