Acoustophoretic purification of platelets: feasibility and impact on platelet activation and function.

Purity, limited platelet activation, and preservation of platelet function are important stakes of preparation of platelet concentrates (PC) for clinical use. In fact, contaminating red blood cells and leukocytes, as well as activated and/or poorly functional platelets in PC, represents a risk of poor efficiency and adverse side effects during platelet transfusion. Therefore, optimization of preparation and storage of PC is still an active field of research. Shear-induced platelet activation is an unwanted side effect of the hard-spin (up to 5000g) step of centrifugation-based methods currently used in blood banks to prepare PC from whole blood samples. Here, we evaluated the effectiveness of an acoustic-based fractionation device for the isolation of human platelets from whole blood bags. The purity, activation status, and functionality of platelets isolated by acoustopheresis were compared with those of platelets isolated using a reference protocol known to produce limited platelet activation and consisting of two consecutive soft-spin centrifugations (120g and 1200g). Platelet concentration and purity were determined using an automated hematology analyzer. Platelet activation status and platelet reactivity to collagen and thrombin were assessed in flow cytometry by measurement of surface expression of P-selectin and activated integrin αIIbß3. The ability of isolated platelets to incorporate into a thrombus when transfused to NOD/SCID mice was investigated by intravital microscopy using the ferric chloride-induced thrombosis model. Blood fractionation by acoustophoresis led to the elimination of more than 80% of red blood cells and leukocytes from the platelet fraction, whose mean purity was of 92.8 ± 12.8%. The activation status and reactivity to collagen and thrombin of acoustophoresis-isolated platelets were similar to those of platelets isolated by soft-spin centrifugation. Finally, acoustophoresis-isolated platelets were tethered, adhered to the vessel wall, and incorporated into a growing thrombus following ferric chloride-induced vascular injury. Together, our results indicate that acoustophoresis is a suitable method for the isolation of human platelets with minimal platelet activation and preservation of platelet function.

Vitrification of human ovarian tissue: a practical and relevant alternative to slow freezing.

BACKGROUND: Cryopreservation of ovarian tissue can be used to preserve the fertility of patients who are about to receive treatment(s) that could compromise their future ovarian function. Here we evaluate the effectiveness of a vitrification protocol by carrying out a systematic comparison with a conventional slow-freezing method on human ovarian tissue. METHODS: Human ovarian samples (mean age 28.0 ± 1.1 years) were processed in parallel for each cryopreservation procedure: vitrification and slow-freezing. Following warming/thawing, histological observations and a TUNEL assay in ovarian follicles were performed and compared to unfrozen control. RESULTS: Both cryopreservation protocols gave comparable histological outcomes. Percentage of intact follicles was 83.6 % following vitrification in a 1.5 M 1,2-propanediol (PrOH), 1.5 M ethylene glycol (EG) and 0.5 M raffinose solution, 80.7 % after slow-freezing in 1.5 M PrOH and 0.025 M raffinose, and 99.6 % in fresh tissue. Follicle density was unchanged by vitrification (0.6 follicles/mm2) or slow-freezing (0.5 follicles/mm2) compared to fresh tissue (0.7 follicles/mm2). Percentage of follicles with DNA fragmentation was not statistically different in vitrified (20.8 %) or slow-frozen (31.3 %) tissues compared to the unfrozen control (35.0 %). There was no difference in proportion of stroma cells with DNA fragmentation in vitrified (6.4 %) and slow-frozen (3.7 %) tissues compared to unfrozen tissue (4.2 %). CONCLUSIONS: This vitrification protocol enables good preservation of ovarian quality post-warming. The evaluation of endocrine function after vitrification need to be perform in a higher cohort to evaluate if this protocol may offer a relevant alternative to conventional slow-freezing for the cryopreservation of human ovarian tissue.

Quality and functionality of human ovarian tissue after cryopreservation using an original slow freezing procedure.

PURPOSE: To evaluate the efficiency of an original slow freezing protocol on the quality and function of human ovarian cortex. METHODS: Human ovarian tissues were cryopreserved using a freezing medium supplemented with propanediol and raffinose as cryoprotectants and antioxidants (L-glutamine, taurine). Samples were then frozen using a faster cooling rate than the usual one. Viability and morphology of follicles, DNA fragmentation in follicles and stroma as well as histology of the vascular endothelium were analyzed before and after freezing/thawing. Moreover, a functional analysis was performed based on the evaluation of follicular growth and development in thawed ovarian tissues that were cultured in vitro. RESULTS: Our freezing/thawing protocol allows preservation of a high proportion of viable follicles and the preservation of the different follicle developmental stages (p>0.05 versus fresh control). 70.5 ± 5.2 % of follicles retained an intact morphology after cryopreservation (p=0.04). Stroma cells but not follicles exhibited a slight increase of DNA fragmentation after thawing (p<0.05). Microvessel endothelium within thawed tissues appeared to be preserved. Granulosa cells showed signs of proliferation in follicles cultured for 12 days. Secretion of 17ß-oestradiol significantly increased during in vitro culture. CONCLUSIONS: This protocol leads to good preservation of ovarian integrity and functionality post-thawing and thus appears as a suitable technique of ovarian tissue cryopreservation in clinical settings. Further research could be extended to optimize conditions of in vitro culture.

The qLabs® FIB system, a novel point-of-care technology for a rapid and accurate quantification of functional fibrinogen concentration from a single drop of citrated whole blood.

Hypofibrinogenemia is often associated with excessive bleeding and requires immediate treatment. The qLabs FIB® is a handheld and easy-to-use point-of-care (POC) device designed for the rapid measurement of functional fibrinogen concentration from a single drop of citrated whole blood. The aim of this study was to evaluate the analytical performances of the qLabs FIB system. Fibrinogen concentrations from 110 citrated whole blood specimen were measured by both the qLabs FIB and the Clauss laboratory reference methods (STA®-Liquid Fib assay on STA-R® Max from Stago). A three-laboratories comparison study was conducted to assess reproducibility and repeatability of the qLabs FIB using plasma quality control material. In addition, single-site assays were conducted to assess the repeatability from citrated whole blood specimen covering the qLabs FIB reportable range. A very strong correlation between the qLabs FIB and the Clauss laboratory reference method was observed (r = 0.95). Using a clinical cut-off value of 2.0 g/L, the area under the receiver operating characteristic curve (ROC) of citrated whole blood was 0.99 and sensibility and specificity were 100 % and 93.5 %, respectively. Percent CVs for reproducibility and repeatability assessed from quality control material, were both <5 %. Repeatability assessed from citrated whole blood specimen showed a CV of 2.6 to 6.5 %. In conclusion, the qLabs FIB system enables a rapid and reliable measurement of functional fibrinogen levels from citrated whole blood and exhibits a strong prediction power at the 2 g/L clinical cut-off when compared to the Clauss laboratory reference. Further clinical studies should demonstrate its ability to quickly confirm the diagnosis of acquired hypofibrinogenemia and help identify patients who may benefit from targeted hemostatic treatment.

Viability assessment of fresh and frozen/thawed isolated human follicles: reliability of two methods (Trypan blue and Calcein AM/ethidium homodimer-1).

PURPOSE: To assess the reliability of trypan blue (TB) and calcein AM/ethidium homodimer-1 (CaAM/EthD-1) staining to evaluate the viability of fresh and thawed human ovarian follicles. METHODS: Isolated follicles from fresh and thawed cortex were stained using TB versus CaAM/EthD-1 methods (n = 10 patients). Measurements were performed by two independent observers. The reliability was evaluated by intraclass correlation coefficient (ICC) and the differences between paired measurements were tested by the Wilcoxon test. RESULTS: Inter-observer reliability was excellent for each method. Nevertheless, it was even better with the TB method (ICC = 0.83) compared with CaAM/EthD-1 (ICC = 0.75). Moreover, the ICCs for viability measurements using the two methods were good for each observer (observer 1: ICC = 0.49; observer 2: ICC = 0.40). CONCLUSION: Compared with CaAM/EthD-1, TB appears to be more reliable as a staining method for follicle viability evaluation. TB staining is a quick and useful method, complementary to histological analysis for quality control in ovarian tissue cryopreservation.

Sensitive and Specific Detection of Ewing Sarcoma Minimal Residual Disease in Ovarian and Testicular Tissues in an In Vitro Model.

Ewing sarcoma (EWS) is a common pediatric solid tumor with high metastatic potential. Due to toxic effects of treatments on reproductive functions, the cryopreservation of ovarian tissue (OT) or testicular tissue (TT) is recommended to preserve fertility. However, the risk of reintroducing residual metastatic tumor cells should be evaluated before fertility restoration. Our goal was to validate a sensitive and specific approach for EWS minimal residual disease (MRD) detection in frozen germinal tissues. Thawed OT (n = 12) and TT (n = 14) were contaminated with tumor RD-ES cells (10, 100, and 1000 cells) and EWS-FLI1 tumor-specific transcript was quantified with RT-qPCR. All contaminated samples were found to be positive, with a strong correlation between RD-ES cell numbers and EWS-FLI1 levels in OT (r = 0.93) and TT (r = 0.96) (p < 0.001). No transcript was detected in uncontaminated control samples. The invasive potential of Ewing cells was evaluated using co-culture techniques. After co-culturing, tumor cells were detected in OT/TT with histology, FISH, and RT-qPCR. In addition, four OT and four TT samples from children with metastatic EWS were tested, and no MRD was found using RT-qPCR and histology. We demonstrated the high sensitivity and specificity of RT-qPCR to detect EWS MRD in OT/TT samples. Clinical trial: NCT02400970.

Studies in an Early Development Window Unveils a Severe HSC Defect in both Murine and Human Fanconi Anemia.

Fanconi anemia (FA) causes bone marrow failure early during childhood, and recent studies indicate that a hematopoietic defect could begin in utero. We performed a unique kinetics study of hematopoiesis in Fancg-/- mouse embryos, between the early embryonic day 11.5 (E11.5) to E12.5 developmental window (when the highest level of hematopoietic stem cells [HSC] amplification takes place) and E14.5. This study reveals a deep HSC defect with exhaustion of proliferative and self-renewal capacities very early during development, together with severe FA clinical and biological manifestations, which are mitigated at E14.5 due to compensatory mechanisms that help to ensure survival of Fancg-/- embryos. It also reports that a deep HSC defect is also observed during human FA development, and that human FA fetal liver (FL) HSCs present a transcriptome profile similar to that of mouse E12.5 Fancg-/- FL HSCs. Altogether, our results highlight that early mouse FL could represent a good alternative model for studying Fanconi pathology.

Large-scale analysis by SAGE reveals new mechanisms of v-erbA oncogene action.

BACKGROUND: The v-erbA oncogene, carried by the Avian Erythroblastosis Virus, derives from the c-erbAalpha proto-oncogene that encodes the nuclear receptor for triiodothyronine (T3R). v-ErbA transforms erythroid progenitors in vitro by blocking their differentiation, supposedly by interference with T3R and RAR (Retinoic Acid Receptor). However, v-ErbA target genes involved in its transforming activity still remain to be identified. RESULTS: By using Serial Analysis of Gene Expression (SAGE), we identified 110 genes deregulated by v-ErbA and potentially implicated in the transformation process. Bioinformatic analysis of promoter sequence and transcriptional assays point out a potential role of c-Myb in the v-ErbA effect. Furthermore, grouping of newly identified target genes by function revealed both expected (chromatin/transcription) and unexpected (protein metabolism) functions potentially deregulated by v-ErbA. We then focused our study on 15 of the new v-ErbA target genes and demonstrated by real time PCR that in majority their expression was activated neither by T3, nor RA, nor during differentiation. This was unexpected based upon the previously known role of v-ErbA. CONCLUSION: This paper suggests the involvement of a wealth of new unanticipated mechanisms of v-ErbA action.