Phosphatidylserine exposing-platelets and microparticles promote procoagulant activity in colon cancer patients

Background: Colon cancer is invariably accompanied by altered coagulation activity; however, the precise role of phosphatidylserine (PS) in the hypercoagulable state of colon cancer patients remains unclear. We explored the exposure of PS on platelets and microparticles (MPs), and evaluate its role in procoagulant activity in colon cancer patients. Methods: PS-positive platelets and MPs, mainly from platelets and endothelial cells, were detected by flow cytometry and confocal microscopy, and their procoagulant activity was assessed with purified coagulation complex assays, clotting time, and fibrin turbidity. Results: Plasma levels of PS-positive platelets increased gradually from stage I to IV and were higher in all stages of the patients than in the healthy control, while PS-positive platelet-derived MPs only increased significantly in stage III/IV patients. Meanwhile, PS-positive MPs and endothelial-derived MPs in stage II/III/IV patients were markedly higher than ones in controls but no difference with stage I. Tissue factor positive MPs were higher in all 4 stages of colon cancer patients than in the healthy control. Platelets and MPs from the patients demonstrated significantly enhanced intrinsic/extrinsic FXa and thrombin generation, greatly shortened coagulation time, and increased fibrin formation. Combined treatment with PS antagonist lactadherin, strongly prolonged the coagulation time and reduced fibrin formation by inhibiting factor tenase and prothrombinase complex activity. In contrast, pretreatment with anti tissue factor antibody played a lesser role in suppression of procoagulant activity. Conclusion: Our results suggest that PS-positive platelets and MPs contribute to hypercoagulability and represent a potential therapeutic target to prevent coagulation in patients with colon cancer

Genetic characterization of human-derived hydatid cysts of Echinococcus granulosus sensu lato in Heilongjiang Province and the first report of G7 genotype of E. canadensis in humans in China.

Cystic echinococcosis (CE) caused by the larval stage of Echinococcus granulosus sensu lato (s.l.) is one of the most important zoonotic parasitic diseases worldwide and 10 genotypes (G1-G10) have been reported. In China, almost all the epidemiological and genotyping studies of E. granulosus s.l. are from the west and northwest pasturing areas. However, in Heilongjiang Province of northeastern China, no molecular information is available on E. granulosus s.l. To understand and to speculate on possible transmission patterns of E. granulosus s.l., we molecularly identified and genotyped 10 hydatid cysts from hepatic CE patients in Heilongjiang Province based on mitochondrial cytochrome c oxidase subunit I (cox1), cytochrome b (cytb) and NADH dehydrogenase subunit 1 (nad1) genes. Two genotypes were identified, G1 genotype (n = 6) and G7 genotype (n = 4). All the six G1 genotype isolates were identical to each other at the cox1 locus; three and two different sequences were obtained at the cytb and nad1 loci, respectively, with two cytb gene sequences not being described previously. G7 genotype isolates were identical to each other at the cox1, cytb and nad1 loci; however, the cytb gene sequence was not described previously. This is the first report of G7 genotype in humans in China. Three new cytb gene sequences from G1 and G7 genotypes might reflect endemic genetic characterizations. Pigs might be the main intermediate hosts of G7 genotype in our investigated area by homology analysis. The results will aid in making more effective control strategies for the prevention of transmission of E. granulosus s.l

Difference in bases and amino acids at the <i>cytb</i> locus of <i>E. granulosus s.l.</i>

a<p>Nucleotide position numbers according to AB235847, with the beginning of the coding region of the <i>cytb</i> gene as position no. 1.</p><p>Difference in bases and amino acids at the <i>cytb</i> locus of <i>E. granulosus s.l.</i></p

Comparison of Phylogenies of different genotypes within <i>E. granulosus s. l.</i> based on <i>cox1, cytb</i> and <i>nad1</i> sequences.

<p>Three phylogenetic trees were constructed using the Neighbor-joining distance method analysis with a Kimura-2-parameter model. The reliability of these trees was assessed using the bootstrap analysis with 1000 replicates. The GenBank accession number, the genotype and the country of origin were given for each isolate of <i>E. granulosus s.l.</i> when available. The squares indicate the sequences of <i>E. granulosus s.l.</i> from the present study.</p

Genotypes of <i>E. granulosus s.l.</i> in humans and animals in China.

<p>*No specific description on geographical source of hydatid cysts in the two provinces.</p><p>Genotypes of <i>E. granulosus s.l.</i> in humans and animals in China.</p

Distribution of G7 genotype of <i>E. canadensis</i> in humans and animals worldwide.

<p>Distribution of G7 genotype of <i>E. canadensis</i> in humans and animals worldwide.</p