Relevance of pre-analytical blood management on the emerging cardiovascular protein biomarkers TWEAK and HMGB1 and on miRNA serum and plasma profiling.

BACKGROUND: Disease-independent sources of biomarker variability include pre-analytical, analytical and biological variance. The aim of the present study was to evaluate whether the pre-analytical phase has any impact on the emerging heart disease TWEAK and HMGB1 protein markers and miRNA biomarkers, and whether peptidome profiling allows the identification of pre-analytical quality markers. METHODS: An assessment was made of sample type (serum, EDTA-Plasma, Citrate-Plasma, ACD-plasma, Heparin-plasma), temperature of sample storage (room temperature or refrigerated), time of sample storage (0.5, 3, 6 and 9h) and centrifugation (one or two-step). Aliquots of all processed samples were immediately frozen (-80°C) before analysis. Proteins were assayed by ELISAs, miRNA expression profile by microarray and peptidome profiling by MALDI-TOF/MS. RESULTS: Temperature, time and centrifugation had no impact on TWEAK and HMGB1 results, which were significantly influenced by matrix type, TWEAK levels being significantly higher (F=194.7, p<0.0001), and HMGB1 levels significantly lower (F=36.32, p<0.0001) in serum than in any other plasma type. Unsuitable miRNA results were obtained using Heparin-plasma. Serum miRNA expression profiles depended mainly on temperature, while EDTA-plasma miRNA expression profiles were strongly affected by the centrifugation method used. MALDI-TOF/MS allowed the identification of seven features as indices of pre-analytical serum (m/z at 1206, 1350, 1865 and 2021) or EDTA-plasma (m/z 1897, 2740 and 2917) degradation. CONCLUSIONS: Serum and EDTA-plasma allow the analysis of both proteins and miRNA emerging biomarkers of heart diseases. Refrigerated storage prevents an altered miRNA expression profile also in cases of a prolonged time-interval between blood drawing and processing.

Erythropoietin therapy and acute preoperative normovolaemic haemodilution in infants undergoing craniosynostosis surgery.

BACKGROUND: A retrospective study was performed to evaluate whether pretreatment with erythropoietin and iron combined with acute preoperative normovolaemic haemodilution (APNH) could decrease homologous blood transfusion in craniosynostosis (CS) surgery. A treated group was compared with a historical group of infants who underwent surgery with no pretreatment. METHODS: The charts of 25 healthy infants who underwent CS surgery were reviewed. Nine of them underwent surgery with no treatment beforehand. Sixteen infants were given erythropoietin at a dosage of 300 U.kg -1 two times per week and iron (elemental iron 10 mg.kg-1.day-1) for 3 weeks before surgery. On the day of surgery APNH was performed after induction of general anaesthesia; a precalculated amount of autologous blood was withdrawn and replaced by hydroxyethyl starch 6%. RESULTS: Eleven of the 16 infants of the study group received only autologous blood. Five of 16 received homologous blood transfusion vs seven of nine infants in the control group. CONCLUSIONS: APNH combined with erythropoietin was effective in reducing homologous blood requirements during CS surgery. Further studies are necessary on a larger scale to assess the role of this technique in avoiding homologous blood transfusion and to evaluate how infants can benefit from this combined approach.