Platelet indices as quality markers of platelet concentrates during storage

An evaluation of diethylhexyl phthalate free top & bottom in-line blood collection set with a new soft housing filter

BACKGROUND AND OBJECTIVES

Di (2-ethylhexyl) phthalate (DEHP) plasticizer must be removed from polyvinylchloride (PVC) medical devices due to toxicity. DEHP/PVC blood bags were shown to provide stable quality under blood component production and to create good storage conditions for red blood cells concentrate (RBC). It is important that substitution of the DEHP maintains the RBC quality during storage, which should be achieved with Di (isononyl) cyclohexane-1,2-dicarboxylate (DINCH), although substitution of the plasticizer has been challenging.

MATERIALS AND METHODS

A DEHP-free Top & Bottom in-line RBC set was validated in a tertiary hospital blood bank facility. Volunteer blood donors were randomly allocated for blood collection into DINCH/PVC or DEHP/PVC set. The groups were additionally divided according to additive solution/filter combination: PAGGS-M + DINCH/PVC filter (only with DINCH/PVC set), and SAG-M + DINCH/PVC filter and SAG-M + DEHP/PVC filter (only with DEHP/PVC set). Processing and storage effects were assessed in all components.

RESULTS

RBC concentrates, platelet concentrates and plasma that was processed and stored in DEHP-free set fulfilled European requirements for quality. The cells stored in PAGGS-M after filtration through DEHP-free PVC filter showed the same low haemolysis compared with conventional set at 49 days of storage. Platelets stored in DINCH/PVC bag provided a sufficient quality of platelets after 7 days of storage. Plasma maintained the coagulation factors during 12 months of storage.

CONCLUSION

A new DINCH/PVC set allows production of blood components of satisfactory quality in DEHP-free environment.

Platelet additive solution suspended apheresis platelets in a tertiary care hospital: A step toward universal single donor platelets

BACKGROUND

Transfusion of ABO-compatible single donor platelets (SDP) is preferable for better outcomes over group switchover SDP. The use of SDP containing ABO-incompatible plasma is associated with a risk of allergic and acute hemolytic transfusion reactions. Moreover, high titer O group donors SDP impose a further threat to patient safety. Platelet additive solution (PAS) is used worldwide for the storage of platelets which reduces plasma volume available in SDP. SSP + (Macopharma) is one such PAS which can provide improved availability, logistical management, decrease wastage, and improvement in patient safety. The aim of this study was to assess the feasibility of using PAS to obtain low titer SDP units which can be utilized across a larger patient population and to study quality control parameters of these units.

MATERIALS AND METHODS

The study was performed in the department of Transfusion Medicine from June 2017 to January 2018 after clearance from the Institutional Review Board. The study design comprised two cohorts (A and B). In cohort A, the temporal trend of in-vitro changes in the quality parameters was tested and analyzed for PAS modified and unmodified products on days 1, 5 and 7. In cohort B, the original plasma from the SDP donors of all blood group donors except the AB group was tested for antibody titers before (prepreparation) and after modification (postpreparation) by PAS.

RESULTS

In cohort A, in the control group, there was a significant change in the mean platelet volume, potassium, and bicarbonate levels from day 1 to day 7, whereas no significant change in the biochemical parameters was noted in the study group where PAS was used. In cohort B, on comparing the anti-A and anti-B, before and after modification of SDP with PAS, there was a significant reduction in the median titers across all the groups studied.

CONCLUSION

PAS added SDP is an efficient strategy to reduce the ABO-antibody levels significantly. PAS added SDP also helps in the better inventory management of available groups.

Effects of whole blood storage in a polyolefin blood bag on platelets for acute normovolemic hemodilution

Acute normovolemic hemodilution (ANH) is a potential transfusion method for platelets, as well as for red blood cells. However, previous studies have shown that whole blood storage in ANH decreases platelet aggregability by 14.7–76.3% and that this decrease is not recovered by reinfusion. We investigated whether a new whole blood storage method for 6 h using a polyolefin bag, based on the platelet concentrates storage method, would maintain platelet function better than the conventional method using a polyvinyl chloride bag. We demonstrated that storage of whole blood in a polyolefin bag maintained ADP-induced aggregation rates at more than twofold higher than those in a polyvinyl chloride bag, and also significantly suppressed P-selectin expression, a platelet activation marker (ADP-induced aggregation rates: 24.6 ± 5.1% vs. 51.7 ± 11.5%, p = 0.002; P-selectin expression; 50.3 ± 8.4MFI vs. 31.6 ± 9.3MFI, p = 0.018). These results could be attributed to the high gas permeability of polyolefin, which lowered PCO₂ and maintained a high pH with or without agitation. There were no significant changes in platelet count and red blood cell parameters due to the storage methods. Our results suggest that ANH using polyolefin bags is advantageous in improving hemostatic function compared to the conventional method.

Quality control in veterinary blood banks: evaluation of canine platelet concentrates stored for five days

Background

Platelets undergo structural, biochemical and functional alterations when stored, and platelet storage lesions reduce platelet function and half-life after transfusion. The objective of this study was to evaluate stored canine platelet concentrates with platelet aggregation, flow cytometry and biochemistry assays. Twenty-two bags of canine platelet concentrates were obtained by the platelet-rich plasma method and were assessed on days 1, 3 and 5 after collection. Parameters such as platelet counts, residual leukocytes, platelet swirling, glucose, lactate, pH, CD62P expression (platelet activation), JC-1 (mitochondrial function) and annexin V (apoptosis and cell death) were assessed.

Results

Over the five days of storage there was a significant decrease in glucose, HCO₃, pCO₂, ATP, pH, swirling and mitochondrial function, associated with a significant increase in lactate levels and pO₂. At the end of storage pH was 5.9 ± 0.6 and lactate levels were 2.8 ± 1.2 mmol/L. Results of the quality parameters evaluated were similar to those reported in human platelets studies. The deleterious effects of storage were more pronounced in bags with higher platelet counts (> 7.49 × 10¹⁰/unit), suggesting that canine platelet concentrates should not contain an excessive number of platelets.

Conclusions

Quality parameters of canine platelets under standard storage conditions were similar to those observed in human platelets. Our results have potential to be used for the routine evaluation and quality control in veterinary blood banks.

Comprehensive metabolomic study of platelets reveals the expression of discrete metabolic phenotypes during storage

BACKGROUND

Platelet (PLT) concentrates are routinely stored for 5 to 7 days. During storage they exhibit what has been termed PLT storage lesion (PSL), which is evident by a loss of hemostatic function when transfused into patients. The overall goal of this study was to obtain a comprehensive data set describing PLT metabolism during storage.

STUDY DESIGN AND METHODS

The experimental approach adopted to achieve this goal combined a series of standard assays to monitor the quality of stored PLTs and a deep-coverage metabolomics study using liquid chromatography coupled with mass spectrometry performed on both the extracellular and the intracellular environments. During storage we measured 174 different variables in 6 PLT units, collected by apheresis. Samples were collected at eight different time points resulting in a data set containing more than 8000 measurements.

RESULTS

Stored PLTs did not undergo a monotonic decay, but experienced systematic changes in metabolism reflected in three discrete metabolic phenotypes: The first (Days 0-3) was associated with active glycolysis, pentose phosphate pathway, and glutathione metabolism and down regulation of tricarboxylic acid (TCA) cycle. The second (Days 4-6) was associated with a more active TCA cycle as well as increased purine metabolism. A third metabolic phenotype of less clinical relevance (Days 7-10) was associated with a faster decay of cellular metabolism.

CONCLUSION

PSL is not associated with a linear decay of metabolism, but rather with successive metabolic shifts. These findings may give new insight into the mechanisms underlying PSL and encourage the deployment of systems biology methods to PSL.

Increased platelet storage time is associated with mitochondrial dysfunction and impaired platelet function

BACKGROUND

Hemorrhagic shock is a leading cause of death following severe trauma, and platelet transfusions are frequently necessary to achieve hemostasis. Platelets, however, require special storage conditions, and storage time has been associated with loss of platelet quality. We hypothesized that standard storage conditions have a deleterious effect on platelet mitochondrial function and platelet activation.

MATERIALS AND METHODS

Platelet donations were collected from healthy donors (n = 5) and stored in gas-permeable collection bags according to American Association of Blood Bank recommendations. Platelet units were sampled from day of collection (day 0) until day 7. High-resolution respirometry was used to assess baseline mitochondrial respiration, maximal oxygen utilization, and individual mitochondrial complex-dependent respiration. Fluorescence-activated cell sorting was performed to analyze mitochondrial content, mitochondrial reactive oxygen species, the expression of P-selectin (both before and after challenge with thrombin receptor-activating peptide), and apoptosis. Data were analyzed using analysis of variance and Pearson correlation (P < 0.05 significant).

RESULTS

Mitochondrial respiration decreased significantly in platelets stored longer than 2 d (P < 0.05). Platelets also demonstrated a persistent decrease in response to stimulation with thrombin receptor-activating peptide by the third day of storage (P < 0.05) as well as an increase in mitochondrial reactive oxygen species and apoptosis (P < 0.05). Mitochondrial respiration significantly correlated with platelet capacity to activate (r = 0.8, P < 0.05).

CONCLUSIONS

Platelet mitochondrial respiratory function and activation response decrease significantly in platelets stored for 3 d or more. Because platelet transfusions almost universally occur between the third and fifth day of storage, our findings may have significant clinical importance and warrant further in vivo analysis.

Platelet activation in chronic urticaria and its correlation with disease severity

Chronic urticaria (CU) is characterized by the occurrence of wheals lasting for more than 6 weeks. The role of platelet activation in the pathophysiology of this condition has not been clearly studied. We undertook a cross-sectional study among 45 patients with CU and 45 age- and gender-matched healthy controls. The severity of the disease was assessed using the urticaria severity score. The autologous plasma skin test (APST) was done in all cases of CU. The platelet count and indices were estimated by an automated haematological laser optical analyzer. Platelet aggregation and soluble P-selectin levels were estimated in all study participants. It was observed that there was a significantly higher mean platelet volume (MPV) and platelet distribution width (PDW) in patients with CU when compared to controls. Platelet aggregation and soluble P-selectin levels were significantly higher in patients with CU, as compared to controls. Urticaria severity score correlated positively with platelet aggregability and soluble P-selectin levels. APST-positive patients had significantly higher platelet aggregation and higher soluble P-selectin levels, when compared to the APST-negative patients, indicating more platelet activation in the autoimmune group. There is significant platelet activation in patients with CU, especially in those with autoreactivity.

Canine reference intervals for the Sysmex XT-2000iV hematology analyzer

BACKGROUND

The laser-based Sysmex XT-2000iV hematology analyzer is increasingly used in veterinary clinical pathology laboratories, and instrument-specific reference intervals for dogs are not available.

OBJECTIVE

The purpose of this study was to establish canine hematologic reference intervals according to International Federation of Clinical Chemistry and Clinical and Laboratory Standards Institute guidelines using the Sysmex XT-2000iV hematology analyzer.

METHODS

Blood samples from 132 healthy purebred dogs from France, selected to represent the most prevalent canine breeds in France, were analyzed. Blood smears were scored for platelet (PLT) aggregates. Reference intervals were established using the nonparametric method. PLT and RBC counts obtained by impedance and optical methods were compared. Effects of sex and age on reference intervals were determined.

RESULTS

The correlation between impedance (I) and optical (O) measurements of RBC and PLT counts was excellent (Pearson r=.99 and .98, respectively); however, there were significant differences between the 2 methods (Student's paired t-test, P<.0001). Differences between sexes were not significant except for HCT, PLT-I, and PLT-O. WBC, lymphocyte, and neutrophil counts decreased significantly with age (ANOVA, P<.05). Median eosinophil counts were higher in Brittany Spaniels (1.87 × 10(9) /L), Rottweilers (1.41 × 10(9) /L), and German Shepherd dogs (1.38 × 10(9) /L) than in the overall population (0.9 × 10(9) /L). PLT aggregates were responsible for lower PLT counts by the impedance, but not the optical, method.

CONCLUSION

Reference intervals for hematologic analytes and indices were determined under controlled preanalytical and analytical conditions for a well-characterized population of dogs according to international recommendations.

Noninvasive pH measurement to monitor changes during suboptimal storage of platelet concentrates

BACKGROUND

Noninvasive pH measurement of platelet concentrates (PCs) was evaluated as a tool for the quality control of PC storage by simulating worst-case conditions.

STUDY DESIGN AND METHODS

PCs from pooling four buffy coats in 70% PAS-3M were both stored in bags wrapped to impair gas permeability and agitated or not until Day 9 of storage. pH values measured both in samples (electrode, blood gas analyzer) and noninvasively by fluorimetry (BCSI pH1000, Blood Cell Storage, Inc.) were compared groupwise and to changes in platelet (PLT) size and biochemical variables.

RESULTS

The noninvasive pH measurements agreed well with the results from each of the two reference methods (R(2) >0.9) in a wide range of pH values between 6.4 and 7.5. Changes of the pH of PCs (n=64) by all interventions (agitation or resting plus occlusion by 0, 25, 50, or 100%; n=8/group) were subtle but already significant after 20 to 24 hours of treatment in comparison to the controls. A steady state after Day 6 and reductions up to a mean pH of approximately 6.5 were observed. The extent of manipulation determined both the absolute pH differences to the controls and the interindividual variation of pH changes. Termination of the agitation significantly enhanced pH reduction by surface blockade. Significant changes were also observed for the mean PLT volume, β-thromboglobulin, and soluble P-selectin.

CONCLUSION

Noninvasive pH measurement in PCs using this technique reliably detects pH changes of 0.1 or more. Storage of PLTs in buffered additive solution requires profound impairment of gas exchange to trigger a substantial decline in pH.

Diagnostic value of platelet indices in children with leukemia

The purpose of this study was to investigate whether platelet indices [mean platelet volume (MPV) and platelet distribution width (PDW)] could serve as diagnostic tools for screening or as surrogate marker for follow-up in children with leukemia. Blood samples were obtained from 47 patients with leukemia at diagnosis before chemotherapy (mean age: 67 mo; 30 males and 17 females) and from 47 healthy controls (mean age: 59 mo; 27 males and 20 females). We measured the blood platelet indices using an automated counter. MPV was higher in the leukemia group, but it was not statistically significant. However, PDW was significantly lower (P<0.001) in leukemia group. There was no significant difference in the MPV or PDW in patients with acute lymphoblastic leukemia versus acute myeloblastic leukemia. In conclusion, we found no significant difference in the MPV between the 2 groups. PDW proposed as indicators of certain pathologic conditions and it seems possible to use PDW as screening. However, platelet indices (MPV and PDW) cannot be used as indicator to discriminate between the subtypes of leukemia in children. The potential role of platelet indices in leukemia remains to be investigated by a multi-institutional level to verify the possible clinical significance of this finding.

Platelet count, mean platelet volume, platelet distribution width, and plateletcrit do not correlate with optical platelet aggegation responses in healthy volunteers

BACKGROUND

Recent advances in technology have made it possible to record various platelet indices. There have been many reports about platelet indices and platelet disorders. The aim of this study is to investigate whether anatomical indices have a correlation with functional aggregation responses using optical method in healthy adults and to evaluate the predictive significance of platelet indices over platelet aggregation responses.

METHODS

This study was carried on 31 adults whose ages ranging between 20 and 42. Platelet parameters, including platelet count, mean platelet volume, platelet distribution width and plateletcrit were determined in platelet rich plasma using Abbott Cell-Dyn 4.000. Platelet aggregation was induced by adenosine diphosphate, collagen and epinephrine. Optical aggregation was performed using a turbidometric method.

RESULTS

We have observed no correlation between any of platelet indices measured and platelet aggregation responses.

CONCLUSIONS

As a result, we found no correlation between platelet aggregation responses obtained with optical method and platelet indices proposed as indicators of certain pathologic conditions, and it does not seem possible to use platelet indices as a direct indicator of platelet activation. In conditions where platelet functions should have been assessed, platelet indices alone are inappropriate and further evaluation is necessary with different methods.

Evaluation of platelet parameters in healthy apheresis donors using the ADVIA 120™

Platelet apheresis is accepted as a safe procedure and no clinically important change is observed after apheresis. The ADVIA 120 provides both an accurate platelet count and parameters describing platelet morphology and function. We studied the changes in platelet parameters of 35 healthy apheresis donors using the ADVIA 120. The mean platelet component value did not change after apheresis but the value of the platelet count was low and this reduction could be due to activation of platelets. We conclude that no remarkable changes were noted except the reduction in platelet numbers and plateletcrit which were expected to return to normal values in a few days.