Atrial Fibrillation Ablation Increases Inflammation-Chemokine Modulation Suppresses Activation of Leukocytes Isolated after Ablation.

AIMS: Atrial fibrillation (AF) ablation is associated with increased circulating markers of inflammation. Innate immune or inflammation pathways up-regulate mononuclear cell responses and may increase the risk for recurrent arrhythmia. Chemokines and serine protease coagulation pathways both activate innate immune responses. Here, we measured inflammatory markers in peripheral blood samples from patients after cryoballoon and/or radiofrequency pulmonary vein isolation and assessed the capacity for the inhibition of chemokine and serine protease pathways to block cell activation. METHODS: Markers of inflammation were measured in 55 patients immediately before and one day after AF ablation. Peripheral blood mononuclear cells (PBMCs) isolated from 19 patients were further tested for responsiveness to two anti-inflammatory proteins ex vivo using fluorescence assays and RT-qPCR analysis of gene expression. RESULTS: White blood cells (WBC), C-reactive protein, fibrinogen and troponin T levels were significantly elevated after ablation. PBMCs isolated from the circulating blood had increased activation with Phorbol 12-myristate 13-acetate. Cell activation, as measured by membrane fluidity, was blunted after treatment with a broad-spectrum chemokine modulating protein, M-T7, which interferes with chemokine/glycosaminoglycan (GAG) interactions, but not by Serp-1, a serine protease inhibitor (serpin) that targets both thrombotic and thrombolytic pathway proteases. Differential gene expression changes in the apoptotic pathway were identified with M-T7 and Serp-1. CONCLUSIONS: Patients undergoing AF ablation have significantly increased inflammatory markers. Inhibition of chemokine signaling, but not serine proteases, reduced the activation of monocytes isolated from patients, in vitro. Targeting chemokines have the potential to reduce post-ablation activation of circulating leukocytes.

Long-term comparison of tacrolimus- and cyclosporine-induced nephrotoxicity in pediatric heart-transplant recipients.

Nephrotoxicity is an adverse effect of cyclosporine and tacrolimus. Studies comparing their long-term nephrotoxicities are lacking. This study evaluates the nephrotoxicity of these agents over a 7-year period following heart transplantation. Pediatric heart-transplant recipients receiving cyclosporine or tacrolimus as primary immunosuppression were evaluated at two centers from 1982 to 1998. Data collected included serum creatinine, height and weight prior to transplantation, at 1 and 6 months and 1 years post transplantation, and at yearly intervals thereafter. Creatinine clearance was calculated and compared between the two groups. Glomerular filtration rate was measured using Tc-99m diethylenetriaminepentacetic acid. In total, 123 patients were evaluated. Demographic data of the two groups were comparable. Creatinine clearance demonstrated a steady decline. This decline did not differ statistically between the two groups: tacrolimus 98.9 and 90.7mL/min/1.73 m2 at 1 month and 5 years, respectively; cyclosporine 110.7 and 81.7 mL/min/ 1.73 m2 at 1 month and 5 years, respectively. Four patients developed end-stage renal failure. Calculated creatinine clearance consistently overestimated glomerular filtration rate, the latter being greater than 2 standard deviations below the mean normal in 38% of patients. We conclude that the nephrotoxicities of tacrolimus and cyclosporine are comparable over the medium- to long-term in pediatric heart-transplant recipients.