Soluble but not platelet P-selectin correlates with spontaneous platelet aggregation: a pilot study

Platelet-Rich Plasma-Embedded Porous Polycaprolactone Film with a Large Surface Area for Effective Hemostasis

BACKGROUND

Uncontrollable and widespread bleeding caused by surgery or sudden accidents can lead to death if not treated with appropriate hemostasis. To prevent excessive life-threatening bleeding, various hemostatic agents based on polymeric biomaterials with various additives for accelerated blood coagulation have been adopted in clinical fields. In particular, platelet-rich plasma (PRP), which contains many blood coagulation factors that can accelerate blood clot formation, is considered as one of the most effective hemostatic additives.

METHODS

We investigated a PRP-embedded porous film using discarded (expired) PRP and a film with a leaf-stacked structure (FLSS), as a hemostatic agent to induce rapid hemostasis. The film, which contained an LSS on one side (PCL-FLSS), was fabricated by a simple heating-cooling technique using tetraglycol and polycaprolactone (PCL) film. Activated PRP was obtained by the thawing of frozen PRP at the end of its expiration date (the platelet cell membrane is disrupted during the freezing and thawing of PRP, thus releasing various coagulation factors) and embedded in the PCL-FLSS (PRP-FLSS).

RESULTS

From in vitro and in vivo experiments using a rat hepatic bleeding model, it was recognized that PRP-FLSS is not only biocompatible but also significantly accelerates blood clotting and thus prevents rapid bleeding, probably due to a synergistic effect of the sufficient supply of various blood coagulants from activated PRP embedded in the LSS layer and the large surface area of the LSS itself.

CONCLUSION

The study suggests that PRP-FLSS, a combination of a porous polymer matrix with a unique morphology and discarded biofunctional resources, can be an advanced hemostatic agent as well as an upcycling platform to avoid the waste of biofunctional resources.

The Role of Platelet-Selectin as a Marker of Thrombocyte Aggregation on Cerebral Sinus Venous Thrombosis

Cerebral sinus venous thrombosis (CVST) is a disease caused by occlusion of intracranial venous structures, including the cerebral sinuses, cortical veins, and the proximal jugular vein. Delay in diagnosis and therapy can lead to complications such as bleeding infarction and even death. Thrombosis that causes CVST is the process of forming a blood clot in a blood vessel. Thrombosis occurs when the balance between thrombogenic factors and the protective mechanisms of thrombogenesis is disturbed. Platelet function abnormalities in CVST cases can be in the form of impaired adhesion function, impaired release or secretion reactions, and impaired aggregation function. Dysfunction and disruption of endothelial structure due to inflammation causes platelet adhesion so that platelets stick together with collagen in endothelial cells. Platelet-selectin is a type 1 transmembrane protein in platelet granules and megakaryocytes and plays a role in mediating interactions between leukocytes and ligands that help the adhesion process of leukocytes and platelets so that they can be used as predictors of thrombosis in patients with CVST.

Increased Soluble VCAM-1 and Normal P-Selectin in Cystic Fibrosis: a Cross-Sectional Study

Purpose

As life expectancy in cystic fibrosis (CF) increases, questions regarding its potential impact on cardiovascular health arise. Soluble vascular cell adhesion molecule 1 (sVCAM-1), P-selectin (sP-selectin) are proposed as biomarkers of cardiovascular disease. We aimed to: compare their concentrations in clinically stable CF patients and healthy subjects (HS) and verify whether they independently correlate with CF characteristics.

Methods

Serum sVCAM-1 and sP-selectin levels were measured using ELISA. CF was characterized using: forced expiratory volume in 1 s, exocrine pancreatic and CF-related liver disease status, Pseudomonas aeruginosa colonization, serum high-sensitivity C-reactive protein, and body mass index (BMI). CFTR genotypes were classified as severe (classes I and II) or other.

Results

108 CF patients and 51 healthy subjects volunteered for the study. In the CF group BMI was lower (median [IQR]: 20.5 kg/m² [18.4–22.2] vs. 21.6 kg/m² [19.9–23.4], p = 0.02) and hsCRP levels were higher (3.6 mg/L [1.1–7.1] vs. 0.5 mg/dL [0.3–1.0], p < 10⁻¹⁰). While sVCAM-1 concentrations were greater in CF patients (1018 ng/mL [851–1279] vs. 861 ng/mL [806–979], p < 10⁻⁴), sP-selectin levels did not differ (155 ng/mL [129–188] vs. 156 ng/mL [144–177], p = 0.48). None of the multivariable regression models was valid for the prediction of sVCAM-1 and sP-selectin in CF.

Conclusions

We found higher sVCAM-1 concentrations in CF patients than in healthy subjects, which were not explained by CF characteristics. Further research is required to check whether sVCAM-1 is a marker of microangiopathy in CF.

Bioprofiling of platelets in medicated patients with depression

BACKGROUND

Changes in platelet bioactivity and aggregation are of interest when studying patients with depression as this could help to explain the statistically observed association of depression and chronic somatic, especially cardiovascular disease. This link could potentially be mediated through serotonergic signaling or immunological changes.

METHODS

38 medicated patients with major depressive disorder (MDD) and 30 mentally healthy controls, both without a diagnosis of cardiovascular disease, were included in this naturalistic study. Demographic and psychometric data were obtained. Platelet aggregability was measured by PFA-100 and bioactive compounds and serotonin levels were quantified in platelet sonicate.

RESULTS

The comparison of patients with controls revealed no changes in platelet aggregability, but significant differences in platelet content of several bioactive compounds. In a second analysis, patients were grouped according to the receptors and transporters influenced by their medication and again compared to controls. A significant effect of MDD was found for platelet content of serotonin, CD40L, interleukin-1β, and platelet factor-4, independent of medication. These markers can thus be classified as sensitive to MDD. The effect of medication on platelet parameters was also evaluated. Platelet content of matrix metalloproteinase-2 and β-thromboglobulin was normalized in MDD patients by medication acting on the serotonin transporter.

LIMITATIONS

Owing to the naturalistic study design, patients were on a variety of different medications and combination therapies. This was accounted for by a novel analysis method.

CONCLUSION

Platelet serotonin levels and content of immunomodulatory compounds are significantly altered in patients with MDD, even if treatment effects are taken into account.

Platelet activity and cardiovascular risk in apparently healthy individuals: a review of the data

Cardiovascular disease is a major cause of morbidity and mortality. Numerous risk scores exist to identify healthy individuals at increased risk of developing cardiovascular disease. Although platelets are a key mediator in the pathogenesis of cardiovascular disease, the role of platelet activity measurements and the incidence of cardiovascular disease are uncertain. Platelet aggregometry-the most well studied method of platelet function testing-is associated with risk factors for cardiovascular disease. However, data supporting platelet aggregation and incident cardiovascular disease is conflicting. Plasma markers of platelet activation are promising candidates. Soluble CD40L and P-selectin are easily measured with a standardized ELISA, and there is some data to suggest an association with cardiovascular disease, but further studies are required. While mean platelet volume is a promising candidate, platelet count and bleeding time are not specific for platelet activity nor are they associated with cardiovascular disease in a healthy population. For this field to progress, we recommend large-scale, prospective studies that measure a battery of these platelet function tests in individuals without cardiovascular disease to better understand the associations, if any, between platelet activity and cardiovascular disease.

Increased serum levels of microvesicles in nonvalvular atrial fibrillation determinated by ELISA using a specific monoclonal antibody AD-1

BACKGROUND

Microvesicles are involved in different pathological processes such as inflammation, coagulation and tumor progression. We intended to establish an immunoaffinity capture method for detecting microvesicles and bioactive effectors carried on them using a specific homemade monoclonal antibody AD-1. By this method we investigated the association of inflammation with platelet activation in patients with nonvalvular atrial fibrillation (NVAF).

METHODS

A case-control study of 90 Chinese subjects selected in 3 groups: control, paroxysmal AF, and persistent AF. After capturing the microvesicles of serum using a specific monoclonal antibody AD-1, the amounts of LAP, IL-1β and P-selectin loaded on these microvesicles were quantified by either enzyme activity assay (LAP) or ELISA respectively.

RESULTS

Compared with normal controls, the patients with persistent AF showed significantly increased serum levels of microvesicles (P<0.001), microvesicle-bound IL-1 β (P=0.019) and microvesicle-bound P-selectin (P=0.001). The latter two were significantly correlated with each other (r(2)=0.371, r=0.616, P<0.001). The microvesicle-bound IL-1β (β=0.570, P<0.001) and body weight (β=0.427, P=0.002) were as independent predictors of platelet activation.

CONCLUSIONS

The method was easy and reproducible. Inflammation may be involved in the activation of platelets in NVAF.

Increased circulating soluble P-selectin in polycystic ovary syndrome

OBJECTIVE

To determine whether the P-selectin-von Willebrand factor (vWF) pathway is altered in patients with polycystic ovary syndrome (PCOS).

DESIGN

Case-control study.

SETTING(S)

Tertiary care academic medical center.

PATIENT(S)

Thirty-two normal glucose-tolerant patients with PCOS and 21 age- and body mass index-matched healthy women were prospectively enrolled. All the patients with PCOS had clinical and/or biochemical hyperandrogenism and chronic oligoanovulation, and 89% had polycystic ovaries on ultrasound.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Soluble P-selectin (sP-selectin), vWF, total T, sex hormone-binding globulin, total cholesterol, high-density lipoprotein cholesterol, triglycerides, fasting glucose and insulin, 2-hour glucose, and homeostatic model assessment-insulin resistance.

RESULT(S)

Soluble P-selectin levels were significantly higher in patients with PCOS compared with controls (58.7 +/- 19.0 vs. 45.3 +/- 15.0 ng/mL), whereas PCOS and control groups had similar vWF levels (46.7 +/- 24.2 vs. 39.5 +/- 22.3, respectively). There was no correlation between sP-selectin and anthropometric measurements or any of the androgen, lipid, or insulin resistance parameters.

CONCLUSION(S)

Our results suggest increments in the circulating sP-selectin concentrations associated with unaltered vWF levels in PCOS. Increased sP-selectin might potentially contribute to the future risk of cardiovascular disease in patients with PCOS.