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Features of the reparative osteogenesis of the distraction of the tibial regenerate and osteotropic growth factors in patients with achondroplasia at the age of 9–12 years

BACKGROUND: Despite studies on various issues of distraction osteosynthesis, many morphological aspects of this problem are still insufficiently studied and remained debatable. 
AIM: To determine the features of the reparative activity of the regenerate and analyze the content of some osteotropic growth factors in children with achondroplasia. 
MATERIALS AND METHODS: Growth factors were determined in serum and blood plasma using equipment from Thermo Fisher (USA). Factor concentrations were determined using ELISA kits: PDGF-AA (RD Systems, USA), PDGF-BB (RD Systems, USA), IGF-1 (Immunodiagnostic systems, USA), IGF-2 (Mediagnost, Germany), TGF-1 (eBioscience, USA), and TGF-2 (eBioscience, USA). The structural state of the tibial regenerate was determined using by ultrasonography (HITACHI, Japan). Patients with achondroplasia aged 912 years (n = 32) were examined at the beginning of distraction (1020 days), in the middle of distraction (2140 days), and at the end of distraction (4163 days). 
RESULTS: The ultrasound method showed the dynamic formation of the structural state of the distraction regenerate at the studied stages of distraction. At the same stages of distraction, the concentration of osteotropic growth factors was assessed. 
CONCLUSIONS: The serum content of osteotropic growth factors in the blood of children with achondroplasia differs from age-normative values. Growth factors that play a key role in osteogenesis, IGF-1, BMP-4, TGF-1, and TGF-2 were reduced, whereas the expressions of IGF-2 and BMP-6 were compensatory increased. At the end of the distraction period, the values of all studied growth factors exceeded the initial values, regardless of their preoperative values and their dynamics at the stages of distraction. The assessment of the dynamics of the concentration of osteotropic growth factors in the blood of patients with achondroplasia during the distraction period and natural growth period indicate the presence of a commonality of processes during the distraction period and prenatal growth of the tibia. Our comprehensive ultrasound study of the structural state of the distraction regenerate of the tibia and biochemical studies of growth factors in the blood of patients with achondroplasia at the age of 912 years made it possible to identify the features of reparative osteogenesis of the distraction regenerate of the tibia and the physiological effect of osteotropic growth factors from the viewpoint of the process of reparative regeneration.