Effect of Tocilizumab on LDL and HDL Characteristics in Patients with Rheumatoid Arthritis. An Observational Study.

BACKGROUND: In patients with rheumatoid arthritis (RA), qualitative alterations of low and high-density lipoproteins (LDL and HDL, respectively) might partially explain their increased cardiovascular risk. Tocilizumab has been associated with an increase in lipids, including triglyceride (TG) and cholesterol levels. The aim of this study is to evaluate the effect of tocilizumab on certain LDL and HDL characteristics (oxidized LDL levels, HDL-associated enzymes, chemical composition of both total HDL and HDL3c subpopulation, and their capacity to promote cellular cholesterol efflux) at baseline and 3 months after the start of treatment in patients with RA. METHODS: Twenty-eight RA patients (ACR/EULAR 2010 criteria) with indication of treatment with tocilizumab were included in the present study. Clinical assessment [Health assessment questionnaire (HAQ)], disease activity score 28 (DAS28), high-sensitivity C reactive protein (hsCRP) concentration, lipid profile, and lipoprotein (a) [Lp(a)] levels were evaluated in all patients at baseline and after 3 months of treatment with tocilizumab. Lipoprotein characteristics were evaluated through the levels of oxidized LDL (OxLDL), the activity of paraoxonase (PON) 1, the composition of total HDL and small, dense HDL3c subpopulation, and their ability to promote cellular cholesterol efflux. RESULTS: After 3 months of treatment with tocilizumab, HAQ (- 23%, p < 0.05), DAS28 (- 49%, p < 0.001), and hsCRP (- 94%, p < 0.01) levels decreased significantly. Total cholesterol (TC), LDL-C, non-HDL-C, and apo B levels showed a significant increase after treatment (TC: + 7.0%, p < 0.01; LDL-C: + 10%, p < 0.01; non-HDL-C: + 9.9%, p < 0.01; and apo B: + 9.6%, p < 0.05). Decreases in Lp(a) and OxLDL levels were also observed after treatment [Lp(a): - 50%, p < 0.01; and oxLDL: - 5.4%, p < 0.05]. The latter was in accordance with the increment detected in PON activity. No changes were observed in HDL capacity to promote cholesterol efflux (p > 0.05) in the whole group. CONCLUSIONS: Treatment with tocilizumab reduced hsCRP levels and displayed positive effects on certain lipoprotein-related parameters, such as a potent decrease inLp(a) and a reduction in OxLDL levels. Moreover, HDL capacity to promote cellular cholesterol efflux was maintained after 3 months of treatment.