Changes in bone metabolism during cerebral palsy

Abstract

Introduction. Patients with cerebral palsy (CP) are especially vulnerable to the development of osteopenia. Skeletal deformities caused by immobility (prolonged bed rest, limited exercise, immobilization), antiepileptic drugs, hormonal and genetic factors can lead to significant bone loss. Diagnosis of osteoporosis includes densitometry and the study of biochemical markers to assess the state of bone mineralization at the time of the examination. However, densitometry in patients with cerebral palsy may present certain difficulties. Purpose is to determine changes in the content of bone tissue metabolism markers in CP patients depending on the severity of movement disorders. Materials and methods. We examined 32 CP patients aged 2 to 15 years for 3 months who were in rehabilitation in 2019-2021. The patients were divided into 2 groups: 18 children in the main group with motor dysfunctions of level IV-V and 14 children in the comparisons group - with disorders of I-III levels. All children underwent an analysis of anthropometric parameters using the program “WHO AnthroPlus (2009)”, determination of the blood levels of biochemical markers of bone tissue metabolism: calcium, phosphorus, alkaline phosphatase, osteocalcin, vitamin D, parathyroid hormone, bone resorption marker β-CrossLaps. Results. The indices of alkaline phosphatase, calcium and phosphorus in the majority of CP patients (88%) were within the reference values. The average concentrations of these compounds did not differ significantly in CP patients in the main group and the comparison group, including between children who received and did not receive antiepileptic drugs. There were no significant differences in 25(OH)D concentrations in patients of these groups. CP patients from the main group were found to be supplemented with vitamin D less frequently than children from the comparison group. Indicators of bone tissue resorption (β-CrossLaps) in patients with cerebral palsy increased significantly more than in patients of the comparison group, which indicates a pronounced loss of bone mass in severe impairment of motor functions. More than half of CP patients have high values of the bone resorption marker β-CrossLaps, which, together with an increase in the level of osteocalcin, indicates active osteoreparation, which is higher in children with severe motor disorders. At the same time, a close correlation (r = 0.596; p < 0.05) between the levels of osteocalcin and β-CrossLaps in patients may indicate activation of bone tissue repair in response to pronounced resorption. However, it should be noted that the determination of biomarkers of bone tissue metabolism in children with cerebral palsy is not indicative in the detection of osteopenia and osteoporosis due to the characteristics of these patients: reduced motor activity, growth retardation and psychophysical development.