The in vitro and in vivo evaluation of whole blood and red cell concentrates drawn on CPDA-1 and stored in a non-DEHP plasticized PVC container

A method to preserve low parasitaemia Plasmodium-infected avian blood for host and vector infectivity assays

Background

Avian malaria vector competence studies are needed to understand more succinctly complex avian parasite-vector-relations. The lack of vector competence trials may be attributed to the difficulty of obtaining gametocytes for the majority of Plasmodium species and lineages. To conduct avian malaria infectivity assays for those Plasmodium spp. and lineages that are refractory to in vitro cultivation, it is necessary to obtain and preserve for short periods sufficient viable merozoites to infect naïve donor birds to be used as gametocyte donors to infect mosquitoes. Currently, there is only one described method for long-term storage of Plasmodium spp.—infected wild avian blood and it is reliable at a parasitaemia of at least 1 %. However, most naturally infected wild-caught birds have a parasitaemia of much less that 1 %. To address this problem, a method for short-term storage of infected wild avian blood with low parasitaemia (even ≤0.0005 %) has been explored and validated.

Methods

To obtain viable infective merozoites, blood was collected from wild birds using a syringe containing the anticoagulant and the red blood cell preservative citrate phosphate dextrose adenine solution (CPDA). Each blood sample was stored at 4 °C for up to 48 h providing sufficient time to determine the species and parasitaemia of Plasmodium spp. in the blood by morphological examination before injecting into donor canaries. Plasmodium spp.—infected blood was inoculated intravenously into canaries and once infection was established, Culex stigmatosoma, Cx. pipiens and Cx. quinquefasciatus mosquitoes were then allowed to feed on the infected canaries to validate the efficacy of this method for mosquito vector competence assays.

Results

Storage of Plasmodium spp.—infected donor blood at 4 °C yielded viable parasites for 48 h. All five experimentally-infected canaries developed clinical signs and were infectious. Pathologic examination of three canaries that later died revealed splenic lesions typical of avian malaria infection. Mosquito infectivity assays demonstrated that Cx. stigmatosoma and Cx. pipiens were competent vectors for Plasmodium cathemerium.

Conclusions

A simple method of collecting and preserving avian whole blood with malaria parasites of low parasitaemia (≤0.0005 %) was developed that remained viable for further experimental bird and mosquito infectivity assays. This method allows researchers interested in conducting infectivity assays on target Plasmodium spp. to collect these parasites directly from nature with minimal impact on wild birds.

Blood Bag Plasticizers Influence Red Blood Cell Vesiculation Rate without Altering the Lipid Composition of the Vesicles

BACKGROUND

Polyvinyl chloride (PVC) plasticized with di(2-ethylhexyl) phthalate (DEHP) is commonly used for blood collection and storage. DEHP has protective effects on RBC membranes, but is also a toxin.

METHODS

A paired study was conducted to investigate the influence of DEHP and two alternative plasticizers, 1,2-cyclohexane-dicarboxylic acid diisononyl ester (DINCH) and n-butyryl-tri-n-hexyl citrate (BTHC), on the preservation of RBCs stored for 42 days in PVC pediatric bags. The RBC membrane was evaluated for supernatant hemoglobin (Hb), release of extracellular microvesicles (EVs), osmotic fragility, deformability, and lipid composition.

RESULTS

In BTHC-plasticized bags, the supernatant Hb increase during storage was 2 times greater than in DINCH- and DEHP-plasticized bags. By day 21, EV concentrations had doubled from day-5 levels in DINCH- and DEHP-, and trebled in BTHC-plasticized bags. RBC mean cell volumes were greater in BTHC- than in DINCH- or DEHP-plasticized bags (p < 0.001). Osmotic fragility differed significantly among plasticizers (p < 0.01). After day 21, RBC deformability decreased in all, but to a greater extent in the bags with BTHC. Phospholipid composition of RBCs and EVs was not different among plasticizers.

CONCLUSION

Membrane stabilization capacity differed among the plasticizers. RBC in BTHC bags stored more poorly, while DEHP and DINCH bags offered better protection against vesiculation, osmotic stress, and Hb loss.

Biochemical and structural changes in RBCs stored with different plasticizers: the role of hexanol

BACKGROUND

PVC containers are plasticized with di(2-ethyl)hexylphthalate (DEHP) or a related phthalate. The toxicity of DEHP has been questioned. It has been proposed to use butyryltrihexylcitrate (BTHC) as the plasticizer. The purpose of this study was to determine if hexanol, a component of BTHC, plays a role in the preservation of RBCs stored in BTHC-plasticized PVC bags.

STUDY DESIGN AND METHODS

WBC-reduced RBCs of ABO- and D-matched blood groups were prepared in 1-L polyolefin (PO) bags (PL732). Six 60-g aliquots were transferred to transfer packs made of PL146 (DEHP-plasticized) and PL2209 (BTHC-plasticized) and four PO (PL732) packs. To the PL146 and PL2209 packs, 30 mL of AS-1 was added. To three of the PO packs, 30 mL of AS-1 with sufficient DEHP, BTHC, or hexanol to achieve a final concentration of 3 mM was added, and to the final PO pack, 30 mL of AS-1 only was added (control). The units were stored for 6 weeks at 1 to 6 degrees C. RBC ATP, hemolysis, morphology, membrane lipids, deformability, and fluidity were measured.

RESULTS

ATP levels were not significantly different in any of the systems after 6 weeks. Compared to the PO bags, hemolysis was lowest in the PL146 containers and was also significantly lower (p < 0.006) in the PO bags with added DEHP, BTHC, or hexanol. The accumulation of vesicles was significantly less in the units stored in the PL146 and PL2209 than in the PO plastic with or without added plasticizers or hexanol (p < or = 0.004). There was no significant difference in the formation of vesicles in any of the PO units (p > 0.05). There was no demonstrable change in the membrane fluidity of the RBCs during storage in any of the systems. The decrease in deformability was the same, and the losses of cholesterol and phospholipid during storage were similar in all the studies.

CONCLUSIONS

The hexanol component of the BHTC plasticizer in a concentration of 144.6 microg per mL concentration suppresses hemolysis and vesiculation of RBCs during storage. The hexanol and DEHP that are slowly leached during storage have a greater effect in suppressing hemolysis and vesicle formation than when added extraneously to AS-1 in PO containers.

Hepatocarcinogenic potential of di(2-ethylhexyl)phthalate in rodents and its implications on human risk

The plasticizer di(2-ethylhexyl) phthalate (DEHP), to which humans are extensively exposed, was found to be hepatocarcinogenic in rats and mice. DEHP is potentially set free from objects made of synthetic materials (e.g., those used in medicine). Chronically, the greatest amounts are transferred to persons undergoing hemodialysis (up to 3.1 mg/kg b.w. per day) who would thus be considered the individuals most endangered by tumorigenesis. Although toxicokinetics seem to play a certain unclear role in the course of DEHP-related toxicity, toxicodynamic factors appear more decisive. DEHP is a representative of "peroxisome proliferators" (PP), a distinct group of substances that, in rodents, do not only induce peroxisomes but also specific enzymes in other organelles, organ growth, and DNA synthesis. The cluster of the characteristic effects of PP is generally, although perhaps not quite appropriately summarized as "peroxisome proliferation," and is strongest in the liver. The lowest observed effect level (LOEL) and the no observed effect level (NOEL) of peroxisome proliferation in the rat, as determined by the induction of specific enzymes (peroxisomal beta-oxidation, carnitine-acetyl-transferase, cytochrome P-452), DNA synthesis, and hepatomegaly, may be assumed as 50 and 25 mg/kg b.w. per day, respectively. DEHP and other carcinogenic PP are neither genotoxic nor tumor initiators, but they appear to be tumor promoters, also implicating a threshold level for the carcinogenic effect. Although a causal relationship between a particular effect of peroxisome proliferation and hepatocarcinogenesis is as yet unknown, peroxisome proliferation as a whole phenomenon appears to be associated with the potential of tumor induction, as shown by comparison of the relative strength of individual PP and by comparison of species and organ specificities. Likewise, LOEL and NOEL of rodent carcinogenesis, that is, 300 and 50 to 100 mg/kg b.w. per day, respectively, are above but not too far from the corresponding values for the investigated parameters of peroxisome proliferation. Thus, with respect to dose alone, worst-case exposure in hemodialysis patients is at least 16-fold below the LOEL of any characterized PP-specific effect of DEHP and approximately 100-fold below that of DEHP-related tumorigenesis. Also, primates are less responsive to PP than rats with respect to the investigated biochemical and morphological parameters. If this lower primate responsiveness is extrapolated to estimate carcinogenicity in humans, we might thus arrive at an even larger safety margin than when based on exposure alone. Doses of PP hypolipidemics that had clearly induced several indicators of peroxisome proliferation in rats did not cause any clear-cut enhancements in the peroxisomes of patients, even though most of these hypolipidemics were considerably stronger PP than DEHP. Thus, an actual threat to humans by DEHP seems rather unlikely. Accordingly, hepatocarcinogenesis was neither enhanced in workers exposed to DEHP nor in patients treated with hypolipidemics.

Selection of anticoagulant-preservatives for canine and feline blood storage

Blood or blood component transfusions have become a well recognized, lifesaving form of therapy in veterinary medicine. Blood used for small animal transfusions may be collected and prepared with a variety of anticoagulants, anticoagulant-preservatives, or additive solutions. Selection of the most appropriate of these collection or storage solutions requires a knowledge of their formulations and of the shelf-lives previously established for storage of canine or feline red blood cells. Other factors that should be considered in the selection process are based on the specific transfusion needs of a clinic and its patients, including whether the blood will be used fresh or stored, the length of storage time desired, and whether components will be prepared. New products and techniques for blood storage continue to be developed, offering exciting new possibilities for the future practice of veterinary transfusion medicine.

Characteristics of white cell-reduced red cells stored in tri-(2-ethylhexyl)trimellitate plastic

BACKGROUND

Standard blood storage containers contain extractable plasticizers that accumulate in blood during storage and are an unintended transfusion product. However, extractable plasticizers have a protective effect on the red cell membrane and improve red cell storage variables. Prestorage white cell reduction also improves selected red cell storage variables.

STUDY DESIGN AND METHODS

The study evaluated whether the beneficial effect of prestorage white cell reduction would offset the negative effect of the absence of extractable plasticizer in red cells stored in AS-3 for 42 days at 4 degrees C. Filtered red cells stored in polyvinylchloride containers with the nonextracting plasticizer, tri-(2-ethylhexyl)trimellitate (TEHTM), were compared to unfiltered red cells stored in polyvinylchloride containers with the extractable plasticizer di-(2-ethylhexyl)phthalate (DEHP).

RESULTS

Poststorage supernatant potassium and red cell osmotic fragility were significantly higher in white cell-reduced TEHTM units than in unfiltered DEHP units. The mean 24-hour recovery of the filtered TEHTM red cells was significantly lower than that of the unfiltered DEHP red cells (69.1 +/- 7.4% vs. 77.1 +/- 5.1%, p < 0.05, n = 8).

CONCLUSION

These data demonstrate that white cell reduction before 42-day storage in TEHTM containers with currently approved preservatives does not yield an acceptable red cell component.

Storage of saline-adenine-glucose-mannitol suspended red cells in diethylhexyl phtalate and butyryl-n-trihexyl-citrate plasticized polyvinyl chloride containers. An in vitro comparative study

Units of whole blood collected into butyryl-n-trihexyl-citrate (BTHC) and diethylhexyl phtalate (DEHP) plasticized polyvinylchloride (PVC) blood storage containers and processed by means of an 'Optipress', which allows automated removal of the buffy coat, were compared. Units collected into standard PVC containers processed by the traditional method (no buffy coat removal) were used as a control group. The red cell concentrates were suspended in saline-adenine-glucose-mannitol (SAGM) and stored 42 days at 2-6 degrees C. Comparison of the buffy coat depleted red cell concentrates showed that red cell energy and oxygen delivery capacity, as evidenced by ATP and 2,3-DPG values, were slightly better preserved in the BTHC plasticized container, compared to the DEHP container. The red cell membrane, however, was slightly less well preserved, (the hemolysis at day 42 with BTHC ww 0.39%; with DEHP, 0.20%) in this container. The higher ATP levels might lead to a better in vivo recovery of stored red cells. In vivo studies comparing both plastic containers, therefore are indicated in order to determine if these differences have practical significance. A longer holding time of the whole blood at room temperature before processing reduced the hemolysis (42 days stored RCC as 0.26%). Slightly more fibrinopeptide A (FPA) generation and marginally lower pH and 2,3-DPG values were observed in this situation. This finding suggests an effect of higher plasticizer levels on the red cell membrane.

Five-day storage of platelets in a non-diethylhexyl phthalate-plasticized container

A non-diethylhexyl phthalate (DEHP)-plasticized blood bag for 5-day storage of random-donor platelet concentrates has been developed. The plastic bag is composed of polyvinylchloride plastic with a butyryl trihexyl citrate plasticizer. The suitability of this plastic for the storage of platelet concentrates for use in clinical transfusion practice was evaluated. In vitro storage studies showed no significant differences at Day 5 for a series of in vitro assays (test plastic vs. control plastic) including pH (7.31 vs. 7.44), lactate dehydrogenase discharge (21.8 vs. 17.1%), pO2 (103 vs. 120 torr), osmotic recovery (52 vs. 57%), and morphology score (527 vs. 516). For paired radiolabeled recovery and survival data from autologous blood donors, results showed equivalence between the test plastic and two control plastics. A small but significant difference between test and control plastics in regard to survival was found by using a linear computer model, but not with a gamma function (multiple-hit) model. For paired transfusions to thrombocytopenic patients, the corrected count increments at 1 to 4 hours (test vs. control) were 13,534 versus 15,494 (p > 0.05, NS). Similar results were seen for corrected count increments determined at 12 to 24 hours. It can be concluded that platelets stored in the test plastic are acceptable for use in clinical practice.