Screening platelet function in blood donors.

BACKGROUND: Transfusion of defective platelets could contribute to the inefficiency of platelet transfusion in preventing or stopping bleeding. STUDY DESIGN AND METHODS: This single-center prospective study aimed to determine the prevalence of functional platelet abnormalities in a population of blood donors with a clinical history of bleeding diathesis or with history of hematoma (>4 cm) during blood donation. Donors with positive bleeding screening questionnaire were referred to the reference center for rare platelet diseases at La Timone University Hospital (Marseille) to confirm the bleeding tendency using a more extensive bleeding questionnaire (MCMDMscore) and to assess hemostasis, including a comprehensive platelet analysis. RESULTS: One hundred and ninety-five donors identified based on a history of hematoma and 2434 blood donors were included in the study. Eighty-eight donors (3.6%) had a bleeding score indicating a potential bleeding disorder. Five donors with a history of hematoma (2.5%) and 15 (17%) donors with a confirmed bleeding score underwent hemostatic analysis, including two men and 18 women with average age of 33.9 years. Minor hemostatic abnormalities were observed in three donors. Two donors exhibited accelerated fibrinolysis with reduced euglobulin lysis time and increased D-dimer levels in serum. Two donors had a platelet granule defect, without identification of genetic abnormality. CONCLUSION: The bleeding questionnaire proved to be a valuable tool to screen blood donors for potential platelet defects. Platelet dysfunction was rare in the blood donor population assessed. Additional studies are necessary to understand the clinical impact that the transfusion of platelets with qualitative defects has on recipients.

Qualitative and quantitative comparison of cell-free DNA and cell-free fetal DNA isolation by four (semi-)automated extraction methods: impact in two clinical applications: chimerism quantification and noninvasive prenatal diagnosis.

BACKGROUND: Non-invasive molecular analysis of cell-free DNA (cfDNA) became a sensitive biomarker for monitoring organ transplantation or for detection of fetal DNA (cffDNA) in noninvasive prenatal test. In this study, we compared the efficiencies of four (semi)-automated cfDNA isolation instruments using their respective isolation kit: MagNA Pure 24 (Roche®), IDEAL (IDSolution®), LABTurbo 24 (Taigen®) and Chemagic 360 (Perkin Elmer®). The cfDNA was isolated from 5 plasma samples and the Rhesus D (RhD)-cffDNA from 5 maternal plasmas. The cfDNA were quantified by digital droplet PCR (ddPCR), BIABooster system and QUBIT fluorometer. The cfDNA fragment size profiles were assessed by BIABooster system. Chimerism were quantified by home-made ddPCR and Devyser NGS kit. RhD-cffDNA in maternal plasma were detected between weeks 14 and 24 of amenorrhea using free DNA Fetal RHD Kit® (Biorad®). RESULTS: Statistical tests have shown differences in DNA yield depending on the isolation procedure and quantification method used. Magna Pure isolates smaller cfDNA fragment size than other extraction methods (90% ± 9% vs. 74% ± 8%; p = 0.009). Chimerism was only reliable from LABTurbo 24 extractions using the NGS but not with ddPCR whatever extraction methods. RhD-cffDNA were detected by all isolation methods, although IDEAL and LABTurbo 24 systems seemed more efficient. CONCLUSIONS: This comparative study showed a dependency of cfDNA yield depending on isolation procedure and quantification method used. In total, these results suggest that the choice of pre-analytical isolation systems needs to be carefully validated in routine clinical practice.

Evidence of metabolic imbalance and oxidative stress among patients suffering from pressure ulcers.

Background: Pressure ulcers (PU) are serious medical problems that involve several factors. Recent studies suggest that oxidative stress along with chronic inflammation may cause and develop PU. However, the metabolic disturbances underlying PU are not totally known. The purpose of this study is to evaluate biochemical oxidative stress markers in Tunisian patients suffering from PU. Methods: A total of 100 adult patients with PU and 213 healthy adult controls were selected for the study. Biochemical parameters related to immune profiles, and biomarkers of the liver, kidney, and inflammatory proteins were evaluated using recently developed automated measurement methods. Oxidant-antioxidant system markers (malondialdehyde (MDA), carbonyl proteins, total antioxidant potential, total oxidant status (TOS), catalase, and glutathione-S-transferase) were studied using appropriate methods. Results: Patients with PU showed, remarkably, abnormal levels of biochemical markers and relatively higher systemic oxidative stress compared to healthy subjects. This provides the first evidence that alterations in biochemical parameters and oxidative stress are features of PU. Conclusions: Understanding the signaling pathways involved in the development of PU will provide experts with additional knowledge for therapeutic strategies aimed at limiting the oxidative and inflammatory reactions in affected patients. ClinicalTrials.gov ID: NCT0257800.

The Impacts of Ramadan Intermittent Fasting on Oxidant/Antioxidant Stress Biomarkers of Stable Chronic Obstructive Pulmonary Disease Male Patients.

No prior study has evaluated the impacts of Ramadan intermittent fasting (RIF) on oxidant/antioxidant stress (OS/AOS) biomarkers in patients with chronic obstructive pulmonary disease (COPD). The aim of this study was to assess the impacts of RIF on some OS/AOS biomarkers measured in male patients with stable COPD. Fifteen COPD patients (mean age: 71 ± 6 years) fasting Ramadan in 2017 volunteered to take part in the study. Three sessions (before Ramadan [BR], end Ramadan [ER], after Ramadan [AR]) were selected. Blood samples of OS (homocysteine [µmol/L], thiobarbituric acid reactive substances [TBARS, µmol/L]) and AOS (catalase [U/ml], ceruloplasmin [g/L], superoxide dismutase [SOD, ng/ml], zinc [µmol/L], albumin [g/L]) biomarkers were consistently taken 4.5 to 2.5 hr before the iftar. Findings were analyzed by applying Friedman or Kruskal-Wallis ANOVA. Comparisons of the number of patients with high OS [high homocysteine and/or TBARS] and low AOS (low catalase and/or ceruloplasmin and/or SOD and/or zinc and/or albumin) blood values between the three sessions were performed using the Cochran test. The median ± interquartile of homocysteine (BR: 21.48 [18.98-24.49], ER: 23.15 [21.77-26.45], AR: 24.87 [21.91-37.12]), ceruloplasmin (BR: 0.27 [0.24-0.30], ER: 0.28 [0.26-0.33], AR: 0.28 [0.25-0.32]), SOD (BR: 288.00 [112.00-400.00], ER: 182.00 [152.00-386.00], AR: 234.00 [190.00-420.00]) and the mean ± SD of TBARS (BR: 5.66 ± 1.26, ER: 4.59 ± 0.78, AR: 5.29 ± 1.69), catalase (BR: 120.97 ± 54.62, ER: 106.73 ± 50.92, AR: 137.39 ± 40.88), zinc (BR: 11.85 ± 2.01, ER: 12.47 ± 2.34, AR: 12.21 ± 2.58) and albumin (BR: 39.78 ± 3.19, ER: 40.74 ± 2.26, AR: 40.56 ± 2.38) were not significantly affected by RIF. The number of patients with high OS (BR [ n = 13], ER [ n = 15], AR [ n = 14]) or low AOS (BR [ n = 12], ER [ n = 13], AR [ n = 13]) statuses were not significantly influenced by RIF. In conclusion, RIF did not induce any significant statistical or clinical changes in OS/AOS biomarkers or statuses in COPD patients.

Use of platelet-rich plasma in regenerative medicine: technical tools for correct quality control.

BACKGROUND/AIMS: Platelet-rich plasma (PRP) injections are used in sports medicine and have been the subject of increased clinical interest. However, there have been very few reports of the composition of initial whole blood and the final PRP product. The objective of this study was to provide technical tools to perform a correct characterisation of platelets, leucocytes and red blood cells (RBCs) from whole blood and PRP. METHODS: Blood and PRP were obtained from 26 healthy volunteers and prepared according to the varying parameters encountered within PRP process preparation and quantification (harvesting method, anticoagulant used, sampling method, counting method). Concentrations were measured at t=0, t=1, t=6 and t=24 hours. RESULTS: Sampling of blood in Eppendorf tubes significantly decreased platelet concentration over time, whereas sampling in Microvette EDTA-coated tube kept platelet concentration stable until 24 hours. A non-significant difference was observed in platelet counts in PRP with impedance (median (IQR): 521.8 G/L (505.3-524.7)) and fluorescence (591.5 G/L (581.5-595.8)) methods. Other studied parameters did not influence platelet concentrations in blood or PRP samples. Leucocytes and RBC counts were similar whatever the anticoagulant, sampling, harvesting and counting methods used for both blood and PRP samples. CONCLUSIONS: Systematic sampling of blood and PRP in EDTA-coated tubes for quality control is recommended. The use of a validated counter for PRP sample should also be taken into account.