PRODUCTION OF PLATELETS FOR TRANSFUSION - CURRENT METHODS AND PROBLEMS TO BE SOLVED

1987 ◽  
Author(s):  
M K Elias ◽  
C Th Smit Sibinga
Keyword(s):  
Whole Blood ◽  
Platelet Rich Plasma ◽  
Synthetic Medium ◽  
Buffy Coat ◽  
Cotton Wool ◽  
Single Donor ◽  
Increased Risk ◽  
Multiple Donors ◽  
And Storage ◽  
Selection Of

Initially, whole blood or platelet rich plasma were used as sources of platelets. Nowadays the methods of platelet concentrates (pc) production adopted in Blood Banks include the traditional method of platelet preparation by differential centrifugation of units of whole blood, besides the much more sophisticated technique of extracorporeal collection of pc with improved immunological compatibility.Manually pc are produced by the platelet rich plasmamethod, the buffy coat method and multiple bag plateletapheresis. The machine collection of pc is done by plateletapheresis or platelet elutriation, with different degrees of automation.The standard manual method remains quantitatively the most important source of platelets.However, there are major concerns:-the need of multiple donors-The high contamination with white cells, predominantly lymphocytes-these pc are depleted from larger and more active platelets, as these are sedimented with the red cells-increased risk of bacterial contamination. To solve these problems there are some potention solutions:-use of single donor collectioon techniques-depletion of leucocytes by:a.elutriation of platelets from the buffy coatb.filtration of random pc through cotton wool columnc. prostacyclin inhibition of platelet aggregation followed by cellulose acetate filtrationd.filtration on elutriated platelets through cotton wool-use of a platelet synthetic medium void of glucose for resuspension and storage of pc to prevent lactate accumulation and pH fall-use of closed sterile harness systems to collect platelets by surge plateletapheresis, which allows extended storage of leucocyte depleted pc.Selection of the most appropriate platelet concentrate depends on the interrelationship of many factors:1) yield 2) function 3) viability after storage 4) afety 5) purity 6) potency 7) efficacy (recovery, survival and haemostatic capacity).

WHOLE BLOOD AGGREGOMETER IN THE ASSESSMENT OF PLATELET HYPER-AGGREGABILITY

1987 ◽  
Author(s):  
R Abbate ◽  
M Boddi ◽  
S Favilla ◽  
G Costanzo ◽  
R Paniccia ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Whole Blood ◽  
Platelet Rich Plasma ◽  
Vascular Complications ◽  
Thromboembolic Complications ◽  
Significant Difference ◽  
Platelet Number ◽  
Patient Groups ◽  
Clinical Conditions ◽  
Selection Of

The aim of this study has been to investigate the reliability of platelet aggregation in whole blood in some clinical conditions associated to thromboembolic complications.18 healthy subjects, 15 patients affected by ischemic heart disease (IHD) and 15 patients affected by insulin independent diabetes, free of vascular complications, were studied. Collagen induced (2.5 mg/L f.c.) platelet aggregation was evaluated both in whole blood (WB) by using impedance whole blood aggregometer (Chrono-Log) and in platelet rich plasma (PRP) by Born aggregometer. Aggregation was significantly higher in whole blood than in PRP in all the groups investigated (p < 0.01). No significant difference was found in PRP aggregation among the three groups, whereas WB aggregation was significantly higher in the two patient groups (IHD 79.5 + 14.2%, Diabetes 81.3 + 17.6%) than in controls (64.8 ± 14.1%) (p < 0.01 for both comparisons). No relationship was found between WB aggregation and Hct or platelet number in any of the groups studied. A slight relationship was found between megathrombocyte count and WE aggregation values (r=0.31, p < 0.05).Collagen platelet aggregation in WB seems to be provided with higher sensibility than PRP aggregation in detecting hyper-aggregability, probably because it does not imply the selection of platelet populations with loss of larger platelets and of other blood cells.

The Association of Platelet and Red Cell Count with Platelet Impedance Changes in Whole Blood and Light-Scattering Changes in Platelet Rich Plasma: Evidence from the Caerphilly Collaborative Heart Disease Study

1990 ◽  
Vol 64 (02) ◽  
pp. 211-215 ◽  
Author(s):  
Dan S Sharp ◽  
Andrew D Beswick ◽  
John R O'Brien ◽  
Serge Renaud ◽  
John W G Yarnell ◽  
...  
Keyword(s):  
Platelet Count ◽  
Heart Disease ◽  
Platelet Aggregation ◽  
Ischaemic Heart Disease ◽  
Whole Blood ◽  
Platelet Rich Plasma ◽  
Plasma Viscosity ◽  
Red Cell ◽  
Increased Risk ◽  
Rbc Count

SummaryThis epidemiological study was undertaken to explore possible relationships among various haematological indices, prevalent ischaemic heart disease and platelet “function” as measured by two rather different methods. ADP-induced platelet impedance changes in whole blood were strongly associated with prevalent ischaemic heart disease in a general population of 49-66 year men at increased risk. Adenosine diphosphate (ADP) induced platelet aggregation in platelet rich plasma (PRP) at a constant platelet count and also the whole blood platelet count and red cell (RBC) count were strongly and independently related to ADP-induced platelet impedance changes. Both platelet count and platelet aggregation in PRP assessed by changes in optical density were directly related to increasing platelet “sensitivity” as measured by impedance changes in whole blood but RBC count was inversely related. Positive independent relationships between platelet impedance changes and plasma viscosity and fibrinogen were markedly attenuated when platelet count was taken into account, but this finding does not discount a role for these factors in platelet aggregation. No relationship was noted between white blood cell (WBC) count and platelet impedance changes; however, a significant inverse relationship was noted with platelet aggregation in PRP. These findings indicate that laboratory-based experimental findings can be observed in population based studies, and that these haematological factors may be important indicators of ischaemic disease in the population.

Generation of Kinins during Preparation and Storage of Leukoreduced Platelet Concentrates.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 947-947
Author(s):  
Marie Eve Moreau ◽  
Louis Thibault ◽  
Anik Désormeaux ◽  
François Marceau ◽  
Marie-Joëlle de Grandmont ◽  
...  
Keyword(s):  
Whole Blood ◽  
Platelet Rich Plasma ◽  
Storage System ◽  
Reference Population ◽  
Storage Conditions ◽  
Blood Collection ◽  
Converting Enzyme Inhibitors ◽  
Pharmacological Characterization ◽  
And Storage

Abstract BACKGROUND. Severe hypotensive reactions can occur following transfusion of blood components, particularly with platelets concentrates (PCs) leukoreduced with negatively- charged filters. Bradykinin (BK)-related peptides were proposed as a possible cause of this side-effect. This study evaluated the effects of leukoreduction and storage conditions on the levels of two kinins (BK and des-Arg9-BK) in PCs. METHODS. Whole blood donations (n=35) were processed using current PRP (platelet-rich plasma) procedure to prepare leukoreduced and unfiltered components by Leukotrap® RC-PL Whole Blood Collection, Filtration and Storage System. PCs and plasma were stored for 7 days at 20–24°C with agitation. Levels of BK and des-Arg9-BK were measured by specific enzyme immunoassays and HPLC at day 0, 2, 5 and 7 of storage. Mechanisms potentially responsible for accumulation of BK and des-Arg9-BK were studied. RESULTS. On day 0, kinins were measured in significantly higher concentrations in leukoreduced (BK: 101 ± 157 pg/mL; des-Arg9-BK: 194 ± 191 pg/mL) vs unfiltered PCs (BK: 71 ± 121 pg/mL; des-Arg9-BK: 98 ± 114 pg/mL). During storage, both kinins peaked on day 5, with concentrations higher than 1 ng/mL in 22% of leukoreduced as well as unfiltered PCs. Physicochemical and pharmacological characterization of immunoreactive kinins confirmed their nature. In vitro activation of the contact system of the corresponding platelet-poor plasma (PPP) showed that a high kinin concentration on day 5 of the storage corresponded to a low kinin-forming capacity of plasma. On day 7, BK was no longer elevated presumably due to its degradation and the depletion of kinin-forming capacity of the plasma in stored PCs. The activity of metallopeptidases that metabolize BK-related peptides in plasma from PCs were at levels similar to those recorded in the plasma of a normal reference population and were unaffected by storage. CONCLUSIONS. Our results indicate that filtration and storage conditions of PCs contribute to generation of pharmacologically relevant bradykinin levels that might pose a risk in susceptible patients. The clinical relevance of such high concentrations of kinins in PCs remains to be established but could potentially be significant especially in patients treated with angiotensin I-converting enzyme-inhibitors that affect the pathway of BK degradation.

Sensitivity and Efficacy in Measurement of Anti-Platelet Medications.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 1253-1253
Author(s):  
Rachelle Blain ◽  
Peggy Nakagawa ◽  
Melissa Belvedere ◽  
Monika Scherer ◽  
Diane Nugent
Keyword(s):  
Vascular Disease ◽  
Platelet Function ◽  
Whole Blood ◽  
Platelet Rich Plasma ◽  
Large Population ◽  
Adenosine Diphosphate ◽  
Full Effect ◽  
Normal Individuals ◽  
Coagulation Assay ◽  
Selection Of

Abstract INTRODUCTION: Large prospective studies must be performed to measure the true effect of clopidogrel (Plavix) or aspirin (ASA) in prevention of vascular disease. An easy and accurate point of service instrument will facilitate these studies and confirm effectiveness and compliance with medications. With such a variety of equipment available for analysis of platelet dysfunction, it is important to understand the sensitivity and efficacy of each assay when evaluating patients. We have found significant differences in our comparative studies of the PFA-100, optical aggregation, and Thrombelastograph (TEG) platelet coagulation in normal individuals using Plavix or ASA. METHODS: We have compared these three techniques to evaluate their effectiveness in assessing ASA and Plavix inhibition of platelet function. Eighteen normal individuals, who had been examined previously for ASA effect on these instruments, were studied at baseline and after three days of Plavix 75mg daily. All samples were drawn and run simultaneously. The TEG platelet coagulation assay used whole blood in a sodium heparin tube instead of a 3.2 % citrate tube which was used for aggregation and the PFA-100. The PFA-100 whole blood assays included both collagen-epinephrine (EPI) and collagen-adenosine diphosphate (ADP) cartridges. The TEG platelet coagulation assays were run with arachidonic acid (AA) and adenosine diphosphate (ADP) as agonists. The optical aggregation used platelet rich plasma with AA and ADP agonists. RESULTS: We found significant differences between the PFA-100, TEG platelet function, and standard optical aggregation in measurement of Plavix effect. Optical aggregation and the TEG platelet assay did show the effects of Plavix, with the aggregometer being more sensitive than the TEG platelet assay although much more time consuming. In additional studies, the Plavix inhibition became more striking in the TEG by extending treatment to 6 days, suggesting that future studies should be done after a week (rather than 3 days) to see full effect. In contrast, Plavix effect was absent on the PFA-100. All three assays did show the effects of ASA in previously identified aspirin- responsive individuals. Ideally, one instrument could be used to assess response to both agents. However, the sensitivity of the instrument and the pharmacology of these and future medications must play an important role in the selection of which assay will be most informative for these large population studies in the prevention of vascular disease. Figure Figure

scholarly journals The Influence of Low Platelet Count on Whole Blood Aggregometry Assessed by Multiplate

2011 ◽  
Vol 17 (6) ◽  
pp. E211-E217 ◽  
Author(s):  
Trine Stissing ◽  
Nadia P. Dridi ◽  
Sisse R. Ostrowski ◽  
Louise Bochsen ◽  
Pär I. Johansson
Keyword(s):  
Platelet Count ◽  
Platelet Aggregation ◽  
Whole Blood ◽  
Platelet Rich Plasma ◽  
Autologous Plasma ◽  
Platelet Function Test ◽  
Increased Risk ◽  
Platelet Concentration ◽  
Low Platelet Count ◽  
Whole Blood Aggregometry

The Multiplate, a whole blood (WB) platelet function test, has shown promising results identifying patients on antiplatelet therapy at increased risk of rethrombosis. In the present study, the influence of low platelet count on platelet aggregation was analyzed and compared with aggregation results in an artificial matrix, platelet-rich plasma (PRP). Heparinized and citrated blood was diluted with autologous plasma to platelet concentrations 200 to 25 × 109/L in WB samples (n = 10) and 200 to 100 × 109/L in PRP samples (n = 7). The platelet aggregation was investigated by the ADP-, ASPI-, COL-, and TRAP-test. The WB responses decreased at platelet concentration of ≤100 × 109/L (all P < .03), except for heparin-TRAP (50 × 109/L, P = .008) and citrate-ASPI (150 × 109/L, P = .03). In general, WB samples demonstrated higher aggregation than PRP samples at platelet concentrations 200 to 100 × 109/L ( P < .05). In conclusion, platelet concentration of <150 × 109/L may influence Multiplate which should be considered in clinical settings. Furthermore, the findings emphasize the importance of evaluating haemostasis in its natural matrix, WB.

scholarly journals Procoagulant imbalance in Klinefelter syndrome assessed by thrombin generation assay and whole blood thromboelastometry

2020 ◽  
Author(s):  
Indirli Rita ◽  
Emanuele Ferrante ◽  
Erica Scalambrino ◽  
Eriselda Profka ◽  
Marigrazia Clerici ◽  
...  
Keyword(s):  
Whole Blood ◽  
Protein C ◽  
Thrombin Generation ◽  
Klinefelter Syndrome ◽  
Platelet Rich Plasma ◽  
Coagulation Factors ◽  
Cross Sectional Study ◽  
Cross Sectional ◽  
Thrombin Generation Assay ◽  
Increased Risk

Abstract Context Klinefelter syndrome (KS) is a condition at increased risk of thrombosis compared to 46,XY men. Objective To investigate the coagulation balance of KS patients by thrombin generation assay (TGA) and thromboelastometry. Design Observational, cross-sectional study. Setting Three tertiary endocrinological centers in Milan, Italy. Patients or other participants 58 KS patients and 58 age-matched healthy controls were included. Anticoagulant or antiplatelet therapy and known coagulation disorders were exclusion criteria. Interventions TGA was performed in platelet-poor plasma (PPP) and platelet-rich plasma (PRP). Whole-blood thromboelastometry and activities of coagulation factors were assessed. Main Outcome Measures Endogenous thrombin potential (ETP), i.e. the area under the thrombin generation curve, assessed with and without thrombomodulin (ETP-TM + and ETP-TM -), and their ratio (ETP-ratio) were considered as indexes of procoagulant imbalance. Results Patients with KS displayed higher PPP-ETP-TM + (mean 1528vs.1315nMxmin; p&lt;0.001), PPP-ETP-ratio (0.78vs.0.70, p&lt;0.001), factor (F)VIII (135%vs.107%; p=0.001), fibrinogen (283vs.241 mg/dL; p&lt;0.001) and FVIII/protein C ratio (1.21vs.1.06; p&lt;0.05) compared to controls. Protein C was comparable in the two groups. Similar results were observed in PRP. ETP-ratio was positively associated with FVIII (rho=0.538, p&lt;0.001) in KS. Thromboelastometry parameters confirmed evidence of hypercoagulability in KS. Conclusions Patients with KS display a procoagulant imbalance expressed by increased thrombin generation both in PPP and PRP, which is at least in part explained by increased FVIII levels. The procoagulant imbalance, which was confirmed by thromboelastometry, may be responsible for the thrombotic events observed in these patients. Further investigation on the benefit/risk ratio of antithrombotic prophylaxis is warranted.

Time Dependence of Whole Blood Aggregation in Response to Platelet Activating Factor (PAF)

1988 ◽  
Vol 59 (02) ◽  
pp. 162-163 ◽  
Author(s):  
R R Taylor ◽  
J Strophair ◽  
M Sturm ◽  
R Vandongen ◽  
L J Beilin
Keyword(s):  
Time Dependence ◽  
Whole Blood ◽  
Platelet Rich Plasma ◽  
Platelet Activating Factor ◽  
Sampling Time ◽  
Blood Sampling ◽  
Impedance Aggregometry

SummaryThe aggregation/adhesion response to platelet activating factor (PAF) was studied in diluted whole blood by impedance aggregometry. The extent of aggregation varied directly with the interval between blood sampling and aggregation measurement over the first 30 minutes from sampling, then remained stable for the next 60 minutes of observation. This is an effect opposite to that described for aggregation to PAF in platelet rich plasma which, however, cannot be studied soon after sampling. Time dependence of aggregation is important and comparative measurements should be made during the period of stable aggregability.

Macroaggregation of Platelets in Plasma, as Distinct from Microaggregation in Whole Blood (and Plasma), as Determined Using Optical Aggregometry and Platelet Counting respectively, is Specifically Impaired following Cardiopulmonary Bypass in Man

1994 ◽  
Vol 72 (04) ◽  
pp. 511-518 ◽  
Author(s):  
Valentine C Menys ◽  
Philip R Belcher ◽  
Mark I M Noble ◽  
Rhys D Evans ◽  
George E Drossos ◽  
...  
Keyword(s):  
Cardiac Surgery ◽  
Platelet Count ◽  
Cardiopulmonary Bypass ◽  
Whole Blood ◽  
Platelet Rich Plasma ◽  
Interquartile Range ◽  
Contributory Factor ◽  
Platelet Aggregability ◽  
Aggregate Growth

SummaryWe determined changes in platelet aggregability following cardiopulmonary bypass, using optical aggregometry to assess macroaggregation in platelet-rich plasma (PRP), and platelet counting to assess microaggregation both in whole blood and PRP. Hirudin was used as the anticoagulant to maintain normocalcaemia.Microaggregation (%, median and interquartile range) in blood stirred with collagen (0.6 µg/ml) was only marginally impaired following bypass (91 [88, 93] at 10 min postbypass v 95 (92, 96] prebypass; n = 22), whereas macroaggregation (amplitude of response; cm) in PRP stirred with collagen (1.0µg/ml) was markedly impaired (9.5 [8.0, 10.8], n = 41 v 13.4 [12.7,14.3], n = 10; p <0.0001). However, in PRP, despite impairment of macroaggregation (9.1 [8.5, 10.1], n = 12), microaggregation was near-maximal (93 [91, 94]), as in whole blood stirred with collagen. In contrast, in aspirin-treated patients (n = 14), both collagen-induced microaggregation in whole blood (49 [47, 52]) and macroaggregation in PRP (5.1 [3.8, 6.6]) were more markedly impaired, compared with control (both p <0.001).Similarly, in PRP, macroaggregation with ristocetin (1.5 mg/ml) was also impaired following bypass (9.4 [7.2, 10.7], n = 38 v 12.4 [10.0, 13.4]; p <0.0002, n = 20), but as found with collagen, despite impairment of macroaggregation (7.2 [3.5,10.9], n = 12), microaggregation was again near-maximal (96 [93,97]). The response to ristocetin was more markedly impared after bypass in succinylated gelatin (Gelo-fusine) treated patients (5.6 [2.8, 8.6], n = 17; p <0.005 v control), whereas the response to collagen was little different (9.3 v 9.5). In contrast to findings with collagen in aspirin-treated patients, the response to ristocetin was little different to that in controls (8.0 v 8.3). Impairment of macroaggregation with collagen or ristocetin did not correlate with the duration of bypass or the platelet count, indicating that haemodilution is not a contributory factor.In conclusion: (1) Macroaggregation in PRP, as determined using optical aggregometry, is specifically impaired following bypass, and this probably reflects impairment of the build-up of small aggregates into larger aggregates. (2) Impairment of aggregate growth and consolidation could contribute to the haemostatic defect following cardiac surgery.

Haemostatic Platelet Plug Formation in the Isolated Rabbit Mesenteric Preparation - An Analysis of Red Blood Cell Participation

1980 ◽  
Vol 44 (01) ◽  
pp. 006-008 ◽  
Author(s):  
D Bergqvist ◽  
K-E Arfors
Keyword(s):  
Whole Blood ◽  
Platelet Rich Plasma ◽  
Adenosine Diphosphate ◽  
In Vitro Test ◽  
Pharmacological Agents ◽  
Vitro Test ◽  
Releasing Effect ◽  
Plug Formation

SummaryIn a model using an isolated rabbit mesenteric preparation microvessels were transected and the time until haemostatic plugs formed was registered. Perfusion of platelet rich plasma gave no haemostasis whereas whole blood did. Addition of chlorpromazine or adenosine to the whole blood significantly prolonged the time for haemostasis, and addition of ADP to the platelet rich plasma significantly shortened it. It is concluded that red cells are necessary for a normal haemostasis in this model, probably by a combination of a haemodynamic and ADP releasing effect.The fundamental role of platelets in haemostatic plug formation is unquestionable but there are still problems concerning the stimulus for this process to start. Three platelet aggregating substances have been discussed – thrombin, adenosine diphosphate (ADP) and collagen. Evidence speaking in favour of thrombin is, however, very minimal, and the discussion has to be focused on collagen and ADP. In an in vitro system using polyethylene tubings we have shown that "haemostasis" can be obtained without the presence of collagen but against these results can be argued that it is only another in vitro test for platelet aggregation (1).To be able to induce haemostasis in this model, however, the presence of red blood cells is necessary. To further study this problem we have developed a model where haemostatic plug formation can be studied in the isolated rabbit mesentery and we have briefly reported on this (2).Thus, it is possible to perfuse the vessels with whole blood as well as with platelet rich plasma (PRP) and different pharmacological agents of importance.

Antiheparin Activity of Human Serum and Platelet Factor 4

1973 ◽  
Vol 30 (01) ◽  
pp. 093-105 ◽  
Author(s):  
C.H.J Sear ◽  
L Poller ◽  
F.R.C Path
Keyword(s):  
Molecular Weight ◽  
Ionic Strength ◽  
Blood Serum ◽  
Whole Blood ◽  
Platelet Rich Plasma ◽  
Gel Filtration ◽  
Normal Serum ◽  
Platelet Factor ◽  
Mean Values ◽  
Antiheparin Activity

SummaryThe antiheparin activity of normal serum has been studied by comparing the antiheparin activities of sera obtained from normal whole blood, platelet-rich plasma and platelet-’free’ plasma with a purified platelet extract during differential isoelectric precipitation and by gel filtration chromatography.The mean values for the activity of PRP-serum and PFP-serum were 106% (S.D. 11) and 10% (S.D. 3) of untreated whole blood respectively. The activity of whole blood serum, PRP serum and whole blood serum plus platelet extract precipitated under identical physical conditions, i.e. pH 7.0, I =0.008, indicating that the activities of the three samples are probably associated with PF4. PF4 precipitated from human platelet extract at pH 4.0, but this is probably due to the difference in the two biochemical environments investigated, i.e. serum and platelet extract.The gel filtration experiments revealed striking similarities between the major antiheparin activities of serum and platelet extract. At physiological pH and ionic strength both activities were associated with high molecular weight material, but at physiological pH and elevated ionic strength both activities behaved as much smaller entities of molecular weight between 25,000 and 30,000 daltons and it seems very likely that both activities are associated with the same molecule, i.e. PF4.

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