Improved yields of factor VIII from heparinized plasma

Preparation of Cryoprecipitate and Cryo-depleted Plasma for Proteomic Research Analysis

When frozen plasma is slowly thawed in cold conditions (1-6 °C), high-molecular-weight plasma proteins precipitate forming a concentrate known as cryoprecipitate. The concentrate is enriched with several important coagulation proteins, including fibrinogen, antihemophilic factor (factor VIII), von Willebrand factor, fibrin stabilizing factor (factor XIII), fibronectin, and small amounts of other plasma proteins. In current medical practice, clinical-grade preparations of cryoprecipitate are used mostly to correct fibrinogen deficiency caused by acute blood loss or due to functional abnormalities of the fibrinogen protein. In the past, cryoprecipitate was used to treat von Willebrand disease and hemophilia A (factor VIII deficiency), but the availability of more highly purified coagulation factor concentrates or recombinant protein preparations has superseded the use of cryoprecipitate for these coagulopathies. Cryo-depleted plasma (also called cryosupernatant) is the plasma supernatant remaining following removal of the cryoprecipitate from frozen-thawed plasma and contains all the remaining soluble plasma proteins. This protocol describes the research-scale preparation of cryoprecipitate and cryo-depleted plasma suitable for proteomic studies and is based on the procedures used to prepare clinical-grade cryoprecipitate.

A Protocol for the Preparation of Cryoprecipitate and Cryo-depleted Plasma for Proteomic Studies

Cryoprecipitate is a concentrate of high-molecular-weight plasma proteins that precipitate when frozen plasma is slowly thawed at 1-6 °C. The concentrate contains factor VIII (antihemophilic factor), von Willebrand factor (vWF), fibrinogen, factor XIII, fibronectin, and small amounts of other plasma proteins. Clinical grade preparations of cryoprecipitate are mainly used to treat fibrinogen deficiency caused by acute bleeding or functional abnormalities of the fibrinogen protein. In the past, cryoprecipitate was used to treat von Willebrand disease and hemophilia A (factor VIII deficiency), but the availability of more highly purified coagulation factor concentrates or recombinant protein preparations has superseded the use of cryoprecipitate for these coagulopathies. Cryo-depleted plasma ("cryosupernatant") is the plasma supernatant remaining following removal of the cryoprecipitate from frozen-thawed plasma. It contains all the other plasma proteins and clotting factors present in plasma that remain soluble during cold-temperature thawing of the plasma. This protocol describes the clinical-scale preparation of cryoprecipitate and cryo-depleted plasma for proteomic studies.

Enhanced cryoprecipitate for skin graft and donor site wound healing in pigs

Due to similarities in skin characteristics, the authors hypothesise that a pig model would most accurately show the ability of autologous, enhanced cryoprecipitate (eCryo) to improve the wound healing of split-thickness skin grafts (STSGs) and corresponding donor sites. Fifty-two STSGs (5 × 5 cm) were fashioned and treated according to a randomised protocol with an autologous eCryo-treated and a control group. Macroscopic assessment, histological evaluation and cellular composition were completed at days 7, 14, 21 and 28. Thirty-two donor sites were also created and assessed in a similar manner. Histologic analysis showed enhancement of healing over all time points for eCryo-treated donor sites. All other results showed no statistically significant improvement with the use of eCryo. Autologous cryoprecipitate appears to be a safe, inexpensive and easy-to-use alternative to fibrin glue, which carries risks and is, in many cases, prohibitively expensive. Further studies are necessary to evaluate the full potential of eCryo. Interestingly, eCryo application may improve donor site aesthetic appearance. We believe that a pig model most reliably simulates eCryo's behaviour in humans to accurately reflect its future clinical applicability.

A protocol for the preparation of cryoprecipitate and cryodepleted plasma

Cryoprecipitate is a concentrate of high-molecular-weight plasma proteins that precipitate when frozen plasma is slowly thawed at 1-6°C. The concentrate contains factor VIII (antihemophilic factor), von Willebrand factor (vWF), fibrinogen, factor XIII, fibronectin, and small amounts of other plasma proteins. Clinical-grade preparations of cryoprecipitate are mainly used to treat fibrinogen deficiency caused by acute bleeding or functional abnormalities of the fibrinogen protein. In the past, cryoprecipitate was used to treat von Willebrand disease and hemophilia A (factor VIII deficiency), but the availability of more highly purified coagulation factor concentrates or recombinant protein preparations has superseded the use of cryoprecipitate for these coagulopathies. Cryodepleted plasma ("cryosupernatant") is the plasma supernatant that remains following removal of the cryoprecipitate from frozen-thawed plasma. It contains all the other plasma proteins and clotting factors present in plasma that remain soluble during cold-temperature thawing of the plasma.

Novel cryoprecipitate for wound healing and skin grafts in rats

The authors sought to evaluate the ability of locally administered enhanced cryoprecipitate (eCryo) to improve the wound healing of split thickness skin grafts (STSG) and their donor sites. An STSG (5 x 5 cm) was harvested on the back of 30 rats and divided into four areas that were then treated in one of the following groups: A: 'standard' dressing without STSG; B: eCryo without STSG; C: eCryo with STSG coverage and D: STSG alone. Macroscopic and histological assessments (histomorphometric grading scale and cellular composition) were evaluated at days 7, 14, 21 and 28 for wound healing. All wound beds as well as STSGs healed well without any complications. Eighty per cent of the STSG showed a histological graft take of >75% after 28 days. There were no statistically significant differences of macroscopic or histological results between the groups at any time point. Preparation of eCryo is easy and effective. Its use as an adhesive for STSGs is safe and shows similar results as controls. The theoretical benefits of eCryo did not show significant differences. Possible reasons as well as important findings for future research on wound healing are discussed.

Cryoprecipitate production: the use of additives to enhance the yield

Cryoprecipitate is still widely used to treat hemophilia A in developing countries. However, the yield of factor VIII is relatively low averaging, i.e. only 50%. We have attempted to enhance the yield by adding sodium citrate to the plasma following the method of Shanbrom and Owens (Blood 98, 2001, 60a). Fresh-frozen plasma (FFP) units were processed either as control plasma or after the addition of 10% sodium citrate. Cryoprecipitate was produced from both. After resuspension, calcium chloride was added to the citrated cryoprecipitate to correct for excess citrate prior to testing. The levels of FVIII and fibrinogen were determined in both preparations. The citrated cryoprecipitates had varying yields of fibrinogen and FVIII in the cryoprecipitate. The FVIII levels varied from 34% to 215% recovery. Fibrinogen ranged from 55.5% to 121.4%. We found that the addition of increasing amounts of CaCl2 to normal plasma raised the FVIII values from 1.0 to 4 U/ml. To determine the possibility of assay influence we added different quantities of CaCl2 to control plasma and measured the FVIII and activated partial thromboplastin time levels. Addition of citrate to plasma resulted in an increased total amount of cryoprecipitate much of which was citrate. Assays showed considerable ranges in the quantity of FVIII and fibrinogen. Activation of FVIII can be caused by addition of excess calcium.

The quality of red blood cells

The evolving practice of medicine has required a number of changes in red cell product manufacture to ensure that the final product is more specifically tailored to the needs of the individual patient. As a result of the increasing concern over the risks of transfusion pharmaceutical standards of manufacture are now applied to blood component preparation. Studies have been undertaken to define the optimum method of blood processing, and newer technologies are emerging to allow acquisition of a more consistent dose of red cells in a fashion which may minimize the lesion of collection. Use of high efficiency 3+ generation filter technologies reduces leukokine build up during storage and improves the quality and purity of the stored blood product. The combination of new plasticizers for packaging and improved red cell additive solutions should allow the blood center to supply a more functional red cell with longer storage shelf life. Overall these developments should result in the provision of a more consistent dose of fully functional red cells to the recipient who will be less exposed to the undesirable sequelae of transfusion than previously.

Characterization of factors affecting the stability of frozen heparinized plasma

The use of heparin rather than citrate as primary anticoagulant has been shown to significantly improve the initial activity, stability and recovery of factor VIII:C from human plasma, cryoprecipitates or factor VIII concentrates if the plasma was initially frozen at -80 degrees C and subsequently stored at this temperature. If frozen and stored at progressively warmer temperatures however, increasing amounts of insoluble protein aggregates, termed storage precipitates (SPs), were recovered in the thawed plasma and cryoprecipitate fractions. Plasma recovery by centrifugation at 7,000 g for 7 min [Method I (MI)], 2 x 10 min (MII) or 15 min (MIII) had little effect on SP formation after 1 month at any storage temperature. After 4 months at -20 degrees C, more SP was recovered from MIII plasma whereas at -40 degrees C, more SP was recovered from MI plasma. Also, the preparation method had little or no effect on factor VIII:C activity at equivalent storage times or temperatures. A trend towards improved factor VIII recoveries was noted at lower freezing and storage temperatures however. SP formation was associated with reduced fibrinogen levels in the recovered plasma without loss of antithrombin-III or increased fibrinopeptide-A. Western blots showed polymerization of A alpha or gamma-chains of fibrinogen. SP formation was reduced or eliminated with factor XIII inhibitors, antibody to the active factor XIII a subunit or adjustment of heparinized plasma to 5-10 mM sodium citrate before initial freezing and storage. Although plasma factor VIII:C recoveries were only slightly affected at these citrate concentrations under most conditions, its recovery in cryoprecipitates was substantially improved owing to the reduction or absence of SPs.

Half-strength citrate CPD and new additive solutions for improved blood preservation. I. Studies of six experimental solutions

Poor stability of plasma factor VIII in whole blood and loss of erythrocyte 2,3-bis-phosphoglycerate (BPG) during red cell storage are limitations with systems for blood component preparation in current use. This study presents attempts to improve post-collection storage conditions in both these respects using half-strength citrate CPD solution (0.5CPD) for blood collection, which has been shown by others to improve the stability of factor VIII, and some compositions of hypotonic additive solutions for red cell storage containing citrate, adenine, mannitol, and phosphate. Guanosine was also included in some of the media. The erythrocyte BPG concentration was maintained at a normal level for 3-4 weeks with the best of the tested compositions. Total adenine nucleotide concentration was maintained at the original level for 49 days and adenosine triphosphate for 28 days. Spontaneous storage haemolysis was low, 0.31% (mean) +/- 0.08-0.10% (SD) after 49 days in the two best compositions. The intracellular pH was 0.2-0.3 pH units higher than the extracellular pH at the beginning of storage, but this difference gradually diminished and disappeared after 4-5 weeks. We suggest two likely explanations of the effects: the maintenance of intracellular pH at a level sufficiently high not to impair BPG synthesis until after several weeks of storage, and a sufficient supply of phosphate needed in the synthesis of organic phosphate compounds. The content of citrate was selected such that the total amount supplied to a patient in a massive transfusion, when using a combination of 0.5CPD plasma and red cell suspension, would be smaller than that provided by a transfusion of CPD whole blood.

Red cell and platelet concentrates from blood collected into half-strength citrate anticoagulant: improved maintenance of red cell 2,3-diphosphoglycerate in half-citrate red cells

This study confirms previous work suggesting equivalent in vitro properties in blood components prepared from donations collected into half-citrate preservative (HCPD) compared to components derived from donations collected into standard citrate-phosphate-dextrose (CPD) preservatives. In addition, red cell products harvested from HCPD donations showed significantly improved maintenance of pH over storage, and this was reflected in improved maintenance of intracellular 2,3-diphosphoglycerate (2,3-DPG). This effect was observed in whole blood and in red cells suspended in a phosphate-containing additive solution (Tuta AAS). Collection into HCPD also improved 2,3-DPG maintenance in red cell concentrates processed following an 18-hour hold at 22 degrees C. These improvements were less pronounced in red cells suspended in a non-phosphate-containing medium (Fenwal Adsol) in which a higher pH was maintained even in units collected in CPD. Platelets harvested from HCPD blood and suspended in plasma showed equivalent quality to platelets from standard donations. Some deterioration of platelet properties was observed when HCPD platelets were stored in a non-citrate synthetic medium. Together with data indicating improved coagulation factor stability, these results suggest that collection into HCPD improves stored blood quality and may also allow logistical benefits in blood component preparation.

A simple plasma anticoagulant-exchange method to increase the recovery of factor VIII in therapeutic concentrates

Donor blood, primarily anticoagulated by acid citrate dextrose formula A (ACD-A), was separated by means of the HemaScience Autopheresis C plasmapheresis device. The citrated plasma was collected directly into a solution of heparin and calcium chloride to achieve a final plasma-ionised calcium concentration of approximately 2 mM, and a heparin concentration of 1.0 IU/ml. Heparin at this concentration provided adequate anticoagulation, and did not result in insoluble cryoprecipitates. Three pairs of donor-matched 4-kg plasma pools (anticoagulant-exchanged variant and ACD-A-anticoagulated control) were constructed and subsequently fractionated to an intermediate stage. The mean recovery of factor VIII from 3 anticoagulant-exchanged pools (394 IU/kg) was 23% greater than the mean recovery from the matched control pools (319 IU/kg). This increased recovery was not achieved at the expense of specific activity.

Studies on the stability of VIII:C during the manufacture of a factor VIII concentrate for clinical use

The stability of VIII:C was investigated by monitoring samples taken at different points from a routine process for the manufacture of factor VIII concentrate and by examining the stabilising influence of a number of product formulations. Loss of VIII:C over process-finishing procedures (formulation, 0.22 micron filtration, dispensing) was associated with a citrate-induced inactivation which could be prevented by controlling the ionised calcium concentration of the solution. These results were obtained using a one-stage clotting assay but were not observed using a two-stage assay. No evidence for activation was found in vitro (e.g. by FPA generation and VIII:C stability) and the yield increase suggested by the one-stage assay was supported by results from a controlled clinical evaluation.

Human factor VIII from heparinized plasma. Purification and characterization of a single-chain form

Human factor VIII was purified from heparinized blood by cryoprecipitation, poly(ethyleneglycol) precipitation, Affi-Gel blue, aminohexyl, polyelectrolyte E5 and immunoaffinity chromatography. A purification of 280,000-fold over plasma with a specific activity over 5300 units/mg was achieved. Analyses of factor VIII using HPLC indicated a molecular mass of 280-340 kDa. Variation in the native mass may reflect heterogeneity of the protein due to associated lipid since structural analysis confirmed that factor VIII contained variable amounts of free fatty acids and diglycerides and triglycerides, but no phospholipids. Additional characterization by denaturing polyacrylamide gel electrophoresis under reducing conditions, followed by silver staining, showed a major single-chain polypeptide of factor VIII with a mass of approximately 260 kDa. To determine whether proteolyzed forms of factor VIII were present during fractionation, we analysed earlier steps in purification. This revealed additional species of factor VIII eluting faster than the single-chain form during chromatography on polyelectrolyte E5. Gel electrophoresis showed that these species of factor VIII consisted of multiple polypeptide chains, and partial peptide mapping using Staphylococcus aureus V8 protease indicated that they were structurally related. Monoclonal and hemophilic antibodies were used in immunoadsorption experiments to demonstrate that the purified factor VIII was composed predominantly of the 260-kDa factor VIII chain.

Influence of the primary anticoagulant on the recovery of factor VIII in cryoprecipitate

The influence of anticoagulant on overall factor VIII-yield was measured by drawing blood from one donor simultaneously in three bags containing ACD, CPD and heparin, respectively. After parallel processing factor VIII:C and factor VIII:CAg were measured. It is concluded that, under the circumstances used in this experiment, CPD gives the highest yield of factor VIII.

Preparation of high purity factor VIII concentrates

An improved process for producing high purity Factor VIII concentrate has been developed. The improvement was based on the combination of three precipitating agents (polyethylene glycol, glycine and sodium chloride) which heretofore have been used alone in a single step or in separate and distinct steps in a multi-step process. The product was pasteurized in solution (60 degrees C, 10 hrs) to reduce possible risks of virus transmission. The purified product has significantly higher specific activity and lower fibrinogen and immunoglobulin levels when compared to other commercial concentrates.

Small-pool high-yield factor VIII production

Hemophilia care depends on several factors for the production of purified FVIII: plasma procurement, plasma logistics, production method, and efficacy. The latter two are restrictive factors, both for the supply and the safety of FVIII preparations. Conventional production methodology unavoidably recovers only 10 to 20% of usable protein, therefore requiring large pools of source plasma. Related to pool size is the transmission of diseases, which poses unnecessary risks for patients. The development of new technologies to better recover FVIII allows reduction of the pool size: crush-thaw, controlled pore-glass chromatography, and heparin double-cold precipitation techniques. This review will reflect on current production methods, pool size concept, small-pool approaches in FVIII production, and future developments.

Influence of heparin and calcium chloride on assay, stability, and recovery of factor VIII

The influence of heparin alone or in conjunction with calcium chloride on the coagulation assay for factor VIII, on the stability of factor VIII in blood and in plasma, and on the recovery of factor VIII in cryoprecipitate and in an intermediate purity concentrate was investigated. A stabilizing effect of heparin and calcium on factor VIII activity in blood and plasma could be confirmed. We were, however, unable to make use of the higher activity that can, under certain circumstances, be recovered in the cryoprecipitates; this was mainly due to the poor solubility of cryoprecipitates prepared from heparinized blood. Heparin (or the absence of a calcium chelator) also interferes with the recovery of plasma components other than factor VIII.

A process for preparation of 'high-purity' factor VIII by controlled pore glass treatment

A simple process for large-scale manufacture of 'high-purity' factor VIII is described in detail. A crude concentrate prepared from washed cryo is treated with controlled pore glass (CPG, 500 A pore diameter) in proportion of 20-30 ml of CPG to 1 g input of protein. The slurry is poured into a separation column and the effluent purified concentrate collected. The remaining factor VIII in the void volume is displaced by a wash solution. After passage through a 0.2 micron membrane filter the product is dispensed and lyophilized. Maintaining the operating pH at 6.5-6.7 and adding synthetic amino acids improved the yield and solubility. The current concentrate contains 1 unit of factor VIII per mg protein (10 units mg fibrinogen) with a recovery of 250 units/kg plasma. The CPG stage is non-destructive, yielding more than 90% of the input factor VIII. In 1980-1983, more than 3 X 10(6) units have been used in New South Wales, mostly for massive cover in surgical patients. In collaboration with the Commonwealth Serum Laboratories, it is intended to expand production for use in other Australian States.

Pilot study for large-scale plasma procurement using automated plasmapheresis

A pilot study for large-scale automated plasmapheresis using the Haemonetics Model 50 machine was undertaken in the Yorkshire Region of the United Kingdom to determine the viability of such a programme for national self-sufficiency in fresh plasma procurement for factor VIII concentrate production. The study was designed to resolve three areas of concern: donor safety and recruitment; a cost analysis, and the choice of anticoagulant for optimum factor VIII yields. The results show that large-scale automated plasmapheresis could safely and economically produce high-quality source plasma necessary for national self-sufficiency.

The antithrombin III content of cryoprecipitate prepared from blood collected with and without heparin

Antithrombin III (AT III) is a plasma protein which acts as the principal inhibitor of thrombin and is a major modulator of intravascular coagulation. Hereditary deficiency of AT III leads to recurrent episodes of thromboembolism. Acquired deficiency of AT III occurs in persons with a variety of conditions, including severe liver disease and disseminated intravascular coagulation. Replacement of AT III may be important in some deficient persons. To determine if cryoprecipitate is a useful source of AT III, we measured the AT III content of cryoprecipitate prepared from citrate phosphate dextrose blood using coagulation and fluorogenic assays and immunoassays. Using the fluorogenic assay, we also determined the effect of adding heparin to blood on the cryoprecipitation of AT III. Functional and antigenic AT III levels were similar to those of normal plasma in all citrate phosphate dextrose blood units tested, indicating that AT III is not concentrated in cryoprecipitate. Heparin had no effect on the cryoprecipitation of AT III.

Accumulative effect of DDAVP and heparin in increasing plasma factor VIII levels

DDAVP (l-desaminocysteine-(8-D-arginine)-vasopressin) produces a marked increase in plasma factor VIII procoagulant (F VIII:C) levels. Previously, we have reported that blood collected into heparin rather than into CPD anticoagulant results in higher starting levels of plasma F VIII:C activity. We therefore wished to determine whether the effects of these two agents were accumulative and whether they would result in any difference in the relative molecular distribution of F VIII:C. Blood was collected into CPD or heparin immediately before and 15 min after an intravenous dose of 0.2 micrograms/kg body weight of DDAVP. Pre-stimulation factor VIII levels were approximately 36% higher in heparinized plasma than in CPD plasma. Following DDAVP stimulation, the final factor VIII activity was increased 3.9-fold when either of the anticoagulants was used, with the heparin sample maintaining a 37% increase over the CPD sample. Column chromatography on Sepharose CL-6B of pre- and post-DDAVP plasma samples collected into either heparin or CPD indicated that there was no change in the relative distribution of the high and low molecular weight forms of F VIII:C. The heparinized sample showed the typical distribution of approximately 60% F VIII:C at void volume (Vo) and 40% at 2.3 Vo, suggesting that DDAVP-stimulated increases of plasma F VIII:C are equally distributed between the carrier and non-carrier associated F VIII:C activities.