Bone Tissue Remodeling Features in Patients with Systemic Lupus Erythematosus Depending on the Degree of Bone Tissue Mineral Density Reduction

Introduction. Osteoporosis is a systemic disease of the skeleton characterized by a decrease in bone mass and a violation of the microarchitectonics of bone tissue, which leads to increased bone fragility and fractures. Today, osteoporosis is one of the priority health problems due to the high prevalence and severe complications that cause disability and increased mortality among the population. Epidemiological studies have shown that the distribution of low bone mineral density in patients with systemic lupus erythematosus (CLE) is higher in comparison with the general population. Osteopenia in patients with SLE is found in 25.0-75.0% of the cases, and osteoporosis – in 1.4-68.0 %. In a retrospective population study, 702 patients with SLE have shown that the risk of symptomatic transient events caused by osteoporosis in the experimental group is 5 times higher than the control group of healthy women of the same age. Aim. To find out the features of bone remodeling in patients with SLE, depending on the degree of bone mineral density reduction, based on the study of the biochemical bone markers in blood serum. Materials and methods. 68 patients with SLE with reduced bone mineral density by the ultrasound densitometry were randomized into the study. The average duration of the SLE was 10.19 ± 0.84 years; All the women at the time of the survey were in pre-menopausal status. 100.0 % of the patients received methylprednisolone at a dose of 4.0-32.0 mg/day (mean dose – 12.12 ± 0.91 mg/day) and calcium supplements (daily dose of 1000.0 mg) in combination with vitamin D (daily dose – 400.0 IU). Results. The indicators of bone tissue remodeling (β-crossLaps, P1NP, osteocalcin) in the serum of the patients with SLE are significantly higher in patients with SLE compared to the group of healthy individuals that may be caused by both – disease activity and long-term reception of steroids. In patients with SLE in combination with osteoporosis, according to the results of ultrasound densitometry, there were significantly increased markers of the formation of bone tissue – P1NP and osteocalcin, compared with both physically healthy subjects and patients with SLE who have osteopenia of II and III degrees. β-CrossLaps statistically significantly differed only in the groups of practically healthy persons and those with osteopenia of the II degree, which may be due both to the activity of the disease and the long-term use of glucocorticoids. Сonclusions. In patients with SLE there are bone remodeling features depending on the degree of bone tissue mineral density reduction, namely, – in case of osteoporosis, diagnosed by the ultrasound densitometry, remodeling is caused by the significant disorders of osteoblasts and osteoclasts functions, in case of III degree osteopenia – of osteoblasts function.