Characterization of Factors Associated with Tissue Immunity, Cellular Activity and Angiogenesis in Children with Unilateral Cleft Lip and Palate Before and During Primary Dentition: A Comparative Cross-Sectional Study

<b>Introduction</b>: Unilateral cleft lip and palate (CLP) is a severe orofacial birth defect characterized by improper fusion of facial parts and disturbed orofacial functions. The defect manifests as a gap in the orofacial tissues that is accompanied by defective healing patterns and chronic inflammation. The immune system's defense factors modulate immunity, inflammation, and healing. Angiogenesis factors control blood-vessel formation. Therefore, these factors are vital in the immunological assessment and understanding of CLP morphopathogenesis. The aim of the study is to assess the distribution of vascular endothelial growth factor (VEGF), transforming growth factor beta 1 (TGF- β1), the total macrophage population and the M2 subtype, heat-shock proteins (HSP) 60 and 70, and nuclear factor kappa B (NF-κB) p50 and p65 subtypes in the affected tissue of children with CLP before and during primary dentition. <b>Materials and Methods</b>: Tissue samples were obtained from 15 patients aged from 3 to 8 months during veloplastic surgery. Five controls were used for comparison of data. Immunohistochemistry, light microscopy, semi-quantitative evaluation (from 0 to ++++), and statistics (Mann-Whitney U test and Spearman's rank correlation) were used to evaluate the data for statistically significant differences and correlations between the groups. <b>Results</b>: Epithelial tissues affected by CLP presented with statistically significant increases in levels of VEGF (<i>p</i> = 0.007), total macrophages (<i>p</i> = 0.007), HSP60 (<i>p</i> = 0.001), NF-κB p65 (<i>p</i> = 0.000), and p50 (<i>p</i> = 0.045), but with a decrease in M2 macrophages (<i>p</i> = 0.025). Blood vessels in CLP-affected tissues showed a statistically significant increase in levels of NF-κB p65 (<i>p</i> = 0.003) and a statistically significant decrease in M2 numbers (<i>p</i> = 0.014). Connective tissue presented with no statistically significant differences. Spearman's rank correlation revealed multiple statistically significant correlations-26 positive and 5 negative. <b>Conclusions</b>: Statistically significant changes in levels of VEGF and both NF-κB subtypes and numbers of total macrophages and M2 macrophages suggest a possible alteration of variable immune and inflammatory reactions and macrophage functions associated with the initiation and maintenance of the chronic process and the resulting damage.