Intranasal Inhalations of M2 Macrophage Soluble Factors in Children With Developmental Speech Disorders

Neuroinflammation plays a central role in the pathogenesis of any damage to the central nervous system (CNS) profoundly affecting the ability of neural cells to survive and to regenerate. Macrophages play a key role in the regulation of neuroinflammation, but their role is ambiguous. In fact, macrophages can both induce neuronal and glial toxicity and promote tissue repair. The opposite effects of macrophages are largely due to their plasticity and functional heterogeneity. Thus, classical pro-inflammatory macrophages (M1) are tissue-destructive, while anti-inflammatory (M2) macrophages mediate tissue repair. In addition, M2 predominantly induce the Th2 response, which is particularly beneficial in CNS repair. Using low serum conditions the investigators have generated M2-like macrophages and evaluated their phenotypic and functional features \[1\]. The data indicate that M2, in contrast to pro-inflammatory M1, produced significantly lower levels of pro-inflammatory cytokines (IL-1β, tumor necrosis factor-α, IL-6, IL-18, IL-12), chemokines (IL-8, monocyte chemoattractant protein 1-1) and Th1/Th2-cytokines (interferon-γ, IL-2, IL-4) coupled with a high IL-10 level. M2 were capable of producing neurotrophic (brain-derived neurotrophic factor, insulin-like growth factor-1), angiogenic (vascular endothelial growth factor), and other growth factors (erythropoietin, granulocyte-colony stimulating factor, basic fibroblast growth factor, epidermal growth factor) with neuroprotective and regenerative activity. Pilot clinical trials have demonstrated the safety and clinical efficacy of intrathecal administration of M2 in children with severe cerebral palsy \[2, 3\] and in nonacute stroke patients \[4\]. Moreover, intranasal delivery of M2 macrophage-derived soluble products reduces neuropsychological deficit in patients with cerebrovascular disease \[5\]. Given this data, the investigators expect that intranasal administration of the M2-BFs (Bioactive Factors) will reduce the severity of speech disorders in children, including improving speech understanding, sensorimotor speech level, word formation skills, as well as the formation of the grammatical structure of speech and coherent speech. Of note, intranasal administration of M2 soluble factors allow to delivery bioactive agents to brain through the olfactory and trigeminal ways across brain-blood barrier.