Release of Platelet Factor 4 in Vivo during Intravascular Coagulation and in Thrombotic States

1968 ◽  
Vol 19 (03/04) ◽  
pp. 578-583 ◽  
Author(s):  
R Farbiszewski ◽  
S Niewiarowski ◽  
K Worowski ◽  
B Lipiński
Keyword(s):  
Coronary Thrombosis ◽  
Laboratory Diagnosis ◽  
Tolerance Test ◽  
Platelet Factor 4 ◽  
Thrombin Time ◽  
Significant Elevation ◽  
Platelet Factor ◽  
Thrombotic Diseases ◽  
Disseminated Intravascular Clotting

SummaryPlatelet factor 4 released from platelets into the circulating blood was determined using both the heparin thrombin time and paracoagulation methods. It has been found that thrombin injected intravenously into rabbits releases large amounts of this factor. Infusion of plasmin does not release this factor and this finding may be of importance for the differential diagnosis between disseminated intravascular clotting and primary fibrinolysis. PF4 is not released during the hyper coagulable condition induced by HgCl2 intoxication. Only small amounts of this factor are released after contact factor infusion.A significant elevation of extraplatelet PF4 was found in 23 patients with fresh coronary thrombosis and in 9 patients with thrombophlebitis and thromboembolic complications.The significance of the above findings for the pathogenesis, treatment and laboratory diagnosis of thrombotic diseases with particular reference to heparin tolerance test is discussed.

Half-Life of Platelet Factor 4 (PF-4) in Plasma and Platelets from Macaca Mulatta

1977 ◽  
Vol 37 (01) ◽  
pp. 073-080 ◽  
Author(s):  
Knut Gjesdal ◽  
Duncan S. Pepper
Keyword(s):  
Macaca Mulatta ◽  
Half Life ◽  
Human Platelet ◽  
Gel Filtration ◽  
Platelet Factor 4 ◽  
Active Protein ◽  
Platelet Factor ◽  
Membrane Bound

SummaryHuman platelet factor 4 (PF-4) showed a reaction of complete identity with PF-4 from Macaca mulatta when tested against rabbit anti-human-PF-4. Such immunoglobulin was used for quantitative precipitation of in vivo labelled PF-4 in monkey serum. The results suggest that the active protein had an intra-platelet half-life of about 21 hours. In vitro 125I-labelled human PF-4 was injected intravenously into two monkeys and isolated by immuno-precipita-tion from platelet-poor plasma and from platelets disrupted after gel-filtration. Plasma PF-4 was found to have a half-life of 7 to 11 hours. Some of the labelled PF-4 was associated with platelets and this fraction had a rapid initial disappearance rate and a subsequent half-life close to that of plasma PF-4. The results are compatible with the hypothesis that granular PF-4 belongs to a separate compartment, whereas membrane-bound PF-4 and plasma PF-4 may interchange.

Clearance and In Vivo Release by Heparin of Human Platelet Factor 4 (PF4) in the Rabbit

1984 ◽  
Vol 52 (02) ◽  
pp. 157-159 ◽  
Author(s):  
M Prosdocimi ◽  
N Scattolo ◽  
A Zatta ◽  
F Fabris ◽  
F Stevanato ◽  
...  
Keyword(s):  
Half Life ◽  
Human Platelet ◽  
Slow Component ◽  
Platelet Factor 4 ◽  
Platelet Factor ◽  
In Vivo Release ◽  
Partial Release ◽  
Different Doses ◽  
New Zealand Rabbits

Summary13 male New Zealand rabbits were injected with two different doses (25 μg/Kg and 100 μg/Kg) of human platelet factor 4 antigen (PF4). The disappearance of the protein was extremely fast with an half-life for the fast component of 1.07 ± 0.16 and 1.76 ± 0.11 min respectively. The half-life for the slow component, detectable only with the highest dosage, was 18.8 min.The administration of 2500 I.U. of heparin 30 min after PF4 administration induced a partial release of the injected protein and its clearance from plasma was slow, with half-life of 23.3 ± 5.9 min and 30.9 ± 2.19 min respectively.

Detection of Enhanced In Vivo Platelet α-Granule Release in Different Patient Groups - Comparison of β-Thromboglobulin, Platelet Factor 4 and Thrombospondin Assays

1984 ◽  
Vol 52 (02) ◽  
pp. 183-187 ◽  
Author(s):  
D A Lane ◽  
H Ireland ◽  
S Wolff ◽  
E Ranasinghe ◽  
J Dawes
Keyword(s):  
Platelet Factor 4 ◽  
Renal Elimination ◽  
Elevated Plasma ◽  
Platelet Factor ◽  
Release Reaction ◽  
Heparin Anticoagulation ◽  
Patient Groups ◽  
Granule Release ◽  
Sensitive Marker

SummaryDuring the platelet release reaction β-thromboglobulin (βTG), platelet factor 4 (PF4) and thrombospondin (TSP) are released from the platelet into plasma and assays of these proteins can be used to monitor in vivo platelet activation. We have assessed their relative merits as markers of the in vivo platelet α-granule release reaction in a number of patient groups which have previously been shown to have elevated plasma βTG and/or PF4 levels. It is concluded that in diseases or conditions not complicated by its reduced clearance, βTG is the most sensitive marker of in vivo platelet α-granule release. However, the TSP assay may be the least ambiguous when monitoring the platelet α-granule release reaction in patients with renal failure who are undergoing haemodialysis with heparin anticoagulation. Under these circumstances plasma βTG, but not PF4 or TSP, levels are elevated because of impaired renal catabolism, and the presence of a heparin-releasable reservoir of PF4 on the endothelium complicates the use of the PF4 assay. In liver failure none of these assays may accurately reflect platelet α-granule release because of impaired hepatic or renal elimination of the proteins.

In vivo effect of platelet factor 4 (PF4) and tetrapeptide AcSDKP on haemopoiesis of mice treated with 5‐fluorouracil

1996 ◽  
Vol 94 (3) ◽  
pp. 443-448 ◽  
Author(s):  
Sallouha Aidoudi ◽  
Martine Guigon ◽  
Isabelle Lebeurier ◽  
Jacques P. Caen ◽  
Zhong Chao Han
Keyword(s):  
Platelet Factor 4 ◽  
Platelet Factor

Release Of Platelet Factor-4 In Vivo After Heparin Injection

1981 ◽  
Author(s):  
A Koneti Rao ◽  
John C Holt ◽  
Pranee James ◽  
Stefan Niewiarowski
Keyword(s):  
Molecular Weight ◽  
Gel Electrophoresis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Human Platelets ◽  
Platelet Factor 4 ◽  
Plasma Samples ◽  
Platelet Factor ◽  
Immunoreactive Material ◽  
Elution Pattern

A single bolus of heparin administered to 8 normal volunteers resulted in a significant increase in levels in platelet poor plasma (PPP) of platelet factor-4 (PF4) but not low-affinity platelet factor-4/β-thromboglobulin (LA-PF4/βTG). However, the presence of heparin interfered with the binding of 125I-PF4 to antibody in radioimmunoassay (RIA). This effect was overcome by increasing the concentration of NaCl from 0.15 to 0.5 M in the buffer used for RIA. In order to establish that the increased amount of immunoreactive material present in PPP was indeed PF4, the protein was isolated from postheparin plasma. A bolus of 5000 units of porcine lung heparin (Upjohn) was administered intravenously to 2 volunteers and plasma samples obtained before and 5 minutes after the injection. The levels of PF4 in PPP rose from 18 and 10 ng/ml before to 185 and 454 ng/ml at 5 minutes after injection in the two volunteers, respectively. The 5 minute samples were adsorbed to heparin agarose columns and PF4 levels decreased to 16 and 10 ng/ml respectively. The immunoreactive material was eluted with 1.2 M NaCl from the heparin agarose columns, showing typical elution pattern for PF4. This material was applied to SDS-polyacrylamide gel electrophoresis in parallel with purified PF4 obtained from human platelets. RIA carried out on eluates from gel slices revealed a species of the same molecular weight as standard PF4. Thus, heparin injection results in appearance in the circulation of a material identical to PF4. LA-PF4/βTG and PF4 are located in same granules and released in parallel during platelet stimulation. Further, LA-PF4 is cleared from plasma 4 times slower than PF4. Therefore, the elevation of PF4alone suggests release from sites other than platelets.

Localization of distal regulatory domains in the megakaryocyte-specific platelet basic protein/platelet factor 4 gene locus

Blood ◽  
2001 ◽  
Vol 98 (3) ◽  
pp. 610-617 ◽  
Author(s):  
Chunyan Zhang ◽  
Michael A. Thornton ◽  
M. Anna Kowalska ◽  
Bruce S. Sachis ◽  
Michael Feldman ◽  
...  
Keyword(s):  
Gene Locus ◽  
Basic Protein ◽  
Regulatory Region ◽  
Platelet Factor 4 ◽  
Specific Gene ◽  
Sufficient Information ◽  
Specific Expression ◽  
Platelet Factor ◽  
High Level

Abstract The genes for the related human (h) chemokines, PBP (platelet basic protein) and PF4 (platelet factor 4), are within 5.3 kilobases (kb) of each other and form a megakaryocyte-specific gene locus. The hypothesis was considered that the PBP and PF4 genes share a common distal regulatory region(s) that leads to their high-level megakaryocyte-specific expression in vivo. This study examined PBP and PF4 expression in transgenic mice using 4 distinct humanPBP/PF4 gene locus constructs. These studies showed that within the region studied there was sufficient information to regulate tissue-specific expression of both hPBP and hPF4. Indeed this region contained sufficient DNA information to lead to expression levels of PBP and PF4 comparable to the homologous mouse genes in a position-independent, copy number–dependent fashion. These studies also indicated that the DNA domains that led to this expression were distinct for the 2 genes; hPBP expression is regulated by a region that is 1.5 to 4.4 kb upstream of that gene. Expression of hPF4 is regulated by a region that is either intergenic between the 2 genes or immediately downstream of the hPF4 gene. Comparison of the available human and mouse sequences shows conserved flanking region domains containing potential megakaryocyte-related transcriptional factor DNA-binding sites. Further analysis of these regulatory regions may identify enhancer domains involved in megakaryopoiesis that may be useful in the selective expression of other genes in megakaryocytes and platelets as a strategy for regulating hemostasis, thrombosis, and inflammation.

scholarly journals Primary Structure of Human Platelet Factor 4.

1977 ◽  
Author(s):  
F.J. Morgan ◽  
G.S. Begg ◽  
C.N. Chesterman
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Structural Information ◽  
Human Platelet ◽  
Specific Protein ◽  
Platelet Factor 4 ◽  
Platelet Factor ◽  
Tryptic Peptides

The amino acid sequence of human platelet factor 4 (PF4) has been studied. PF4 is a platelet specific protein with antiheparin activity, released from platelets as a proteoglycan complex, whose measurement may provide an important index of platelet activation both in vivo and in vitro. These studies were undertaken to characterize fully the PF4 molecule. PF4 is a stable tetramer, composed of identical subunits, each with a molecular weight based on the sequence studies of approx. 7,770. Each PF4 subunit contains 69 amino acids, including 4 half-cystine (# 10, 12, 36, 37), one tyrosine (# 59), 3 arginine and 8 lysine, but no methionine, phenylalanine or tryptophan residues. The basic residues are predominantly in the C-terminal region. The tryptic peptides were aligned after studies which included tryptic digestion of citraconylated RCM-PF4, and automated Edman degradation of RCM-PF4 and citraconylated tryptic peptides. No glycopeptides were detected. This structural information should enable clear distinction to be made between PF4 and other platelet proteins such as β thromboglobulin. The provisional amino acid sequence of each subunit is:Glu-Ala-Glu-Glu-Asp-Gly-Asp-Leu-Gln-Cys-Leu-Cys-Val-Lys-Thr-Thr-Ser-Gln-Val-Arg-Pro-Arg-His-Ile-Thr-Ser-Leu-Glu-Val-Ile-Lys-Ala-Gly-Pro-His-Cys-Cys-Pro-Thr-Ala-Gln-Ile-Leu-Ala-Thr-Leu-Lys-Asn-Gly-Arg-Lys-Ile-Pro-Leu-Asp-Leu-Gln-Ala-Tyr-Leu-Lys-Ile-Lys(Lys, Lys, Ser, Glx, Leu, Leu)

The Variability of β Thromboglobulin and Platelet Factor 4 in Healthy Subjects

1979 ◽  
Author(s):  
J. Zahavi ◽  
N.A.G. Jones ◽  
M. Dubiel ◽  
J. Leyton ◽  
V.V. Kakkar
Keyword(s):  
Platelet Activation ◽  
Healthy Subjects ◽  
Platelet Factor 4 ◽  
Vascular Changes ◽  
Platelet Activity ◽  
Platelet Factor ◽  
Platelet Concentration ◽  
The Mean ◽  
Age Range

Plasma β TC was measured by radioimmunoassay (RIA)in 202 healthy subjects (age range 12-103); 111 young (mean age 25.2) 34 middle aged (MA) (mean age 55.6) and 57 old (mean age 82.2). Their mean ±1SE plasma β TG levels in ng/ml were 28.3 ± 1.5 (range 3-74), 31.9-2-70 (range 7-65) and 49.99 ± 2.9 (range 14-95) respectively. Plasma βTG level was significantly raised in the old subjects compared to young or MA (p ⩽ 0.0005). Furthermore the ratio of plasma β TG to platelet concentration in whole blood (PC) was higher in the MA subjects compared to the young (p ⩽ 0.009). Plasma platelet factor 4 (PF4) was measured by RIA in 4l healthy subjects, 11 young and 30 old and correlated to plasma βTG. A significant correlation between the 2 proteins was found in the 2 groups (r = 0.8337 in the young and r = 0.0602 in the old subjects), indicating that both proteins are released in-vivo from the same pool and presumably at the same rate. The mean plasma PF4 level in ng/ml was 14.6 (range 6-48) in the young and 18.2 (range 7.7-50) in the old and the ratio of the plasma PF4 to PC was higher in the old subjects (p ⩽ 0.04), These results suggest that in-vivo platelet activation and “release reaction” are increased in old and MA subjects compared to young, presumably due to atherosclerotic vascular changes. This enhanced platelet activity may reflect a pre-thtombotic state.

scholarly journals Lipolysis generates platelet dysfunction after in vivo heparin administration

2002 ◽  
Vol 103 (4) ◽  
pp. 433-440 ◽  
Author(s):  
Elijah W. MURIITHI ◽  
Philip R. BELCHER ◽  
Stephen P. DAY ◽  
Mubarak A. CHAUDHRY ◽  
Muriel J. CASLAKE ◽  
...  
Keyword(s):  
Superoxide Dismutase ◽  
Cardiopulmonary Bypass ◽  
Lipoprotein Lipase ◽  
Whole Blood ◽  
Ex Vivo ◽  
Hepatic Lipase ◽  
Platelet Factor 4 ◽  
Platelet Factor

Heparin, when administered to patients undergoing operations using cardiopulmonary bypass, induces plasma changes that gradually impair platelet macroaggregation, but heparinization of whole blood in vitro does not have this effect. The plasma changes induced by heparin in vivo continue to progress in whole blood ex vivo. Heparin releases several endothelial proteins, including lipoprotein lipase, hepatic lipase, platelet factor-4 and superoxide dismutase. These enzymes, which remain active in plasma ex vivo, may impair platelet macroaggregation after in vivo heparinization and during cardiopulmonary bypass. In the present study, proteins were added in vitro to hirudin (200units·ml-1)-anticoagulated blood from healthy volunteers, and the platelet macroaggregatory responses to ex vivo stimulation with collagen (0.6μg·ml-1) were assessed by whole-blood impedance aggregometry. Over a 4h period, human lipoprotein lipase and human hepatic lipase reduced the platelet macroaggregatory response from 17.0±2.3 to 1.5±1.3 and 1.2±0.6Ω respectively (means±S.D.) (both P<0.01; n = 6). Other lipoprotein lipases also impaired platelet macroaggregation, but platelet factor-4 and superoxide dismutase did not. Platelet macroaggregation showed an inverse linear correlation with plasma concentrations of non-esterified fatty acids (r2 = 0.69; two-sided P<0.0001; n = 8), suggesting that heparin-induced lipolysis inhibits platelet macroaggregation. Lipoprotein degradation products may cause this inhibition by interfering with eicosanoids and other lipid mediators of metabolism.

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