Early Post-Transplant Changes in Lipoprotein(a), Autotaxin Activity, and Lipid Profile: A Prospective Observational Study of Tacrolimus-Treated Kidney Transplant Recipients in Poland

Kidney transplantation (KTx) corrects many uremia-related metabolic disturbances; however, dyslipidemia remains common in kidney transplant recipients and contributes to persistent cardiovascular risk. Lipoprotein(a) [Lp(a)] is a largely genetically determined proatherogenic lipoprotein that increases in advanced chronic kidney disease (CKD) and may decrease after restoration of renal function. Autotaxin (ATX), an enzyme involved in proinflammatory lipid signaling through the ATX-lysophosphatidic acid axis, has also been implicated in cardiovascular pathology, but its early post-transplant dynamics remain poorly characterized. In addition to quantitative lipid abnormalities, CKD is associated with high-density lipoprotein (HDL) dysfunction and reduced paraoxonase-1 (PON-1) activity; however, data on early post-transplant changes in PON-1 activity are limited. In this prospective observational study, lipid profile parameters, Lp(a) concentration, ATX activity, and PON-1 activity were assessed in 55 Caucasian patients with CKD stage 5, most of whom were dialysis-dependent, before and 2-3 weeks after KTx. All recipients received tacrolimus-based maintenance immunosuppression with corticosteroids and mycophenolate mofetil. After KTx, Lp(a) levels decreased by a median of 21% and ATX activity by 28% (both <i>p</i> < 0.001). Lp(a) and ATX showed no cross-sectional or longitudinal association either before or after transplantation, and their percentage changes were not correlated. In contrast, conventional lipid fractions increased significantly, including total cholesterol (+22%), LDL cholesterol (+27%), HDL cholesterol (+24%), and triglycerides (+55%) (all <i>p</i> < 0.001). PON-1 activity increased by approximately 13% after KTx (<i>p</i> < 0.001), and its percentage change correlated positively with the increase in HDL cholesterol. In exploratory analyses, the magnitude of Lp(a) reduction was associated with early graft function: patients with eGFR <45 mL/min/1.73 m² exhibited a significantly smaller decline in Lp(a) than those with better graft function (-4.8% vs. -26.7%, <i>p</i> = 0.009). Multivariable analysis showed that demographic characteristics, body mass index, tacrolimus exposure, and post-transplant eGFR did not independently predict the magnitude of Lp(a) reduction. Tacrolimus trough concentrations and cumulative corticosteroid exposure were not associated with lipid parameters or their changes, except for a single subgroup difference in PON-1 activity of uncertain clinical significance. In summary, in the early period after KTx under tacrolimus-based immunosuppression, Lp(a) concentration and ATX activity decrease, whereas conventional lipid fractions increase and PON-1 activity improves. These changes were not associated with tacrolimus exposure or cumulative corticosteroid dose. The reduction in Lp(a) was associated with early graft function in exploratory analyses, suggesting that recovery of renal function may contribute to early post-transplant Lp(a) dynamics; however, no independent causal relationship was established, and the findings should be interpreted cautiously given the limited sample size and exploratory design. The clinical significance of these changes for long-term cardiovascular and graft outcomes requires further investigation.