Age and gender effects on 15 platelet phenotypes in a Spanish population

Decreased serum PF4 levels correlate with cognitive decline and CSF biomarkers in Alzheimer's disease in a Chinese cohort

BACKGROUND

Platelet factor 4 (PF4), a chemotactic factor secreted from the α-granules of platelets, has recently been proved to mitigate neuroinflammation and improve aging-related cognition decline, which may be involved in Alzheimer's disease (AD).

OBJECTIVE

This study aims to investigate the alterations of serum PF4 levels in AD, the correlation between serum PF4 and β-amyloid (Aβ) and tau levels in cerebrospinal fluid (CSF), and the potential diagnostic utility of PF4 in AD.

METHODS

A cross-sectional study was conducted involving 38 amyloid-positive AD patients and 50 cognitively normal controls. The levels of serum PF4 were detected using the Human CXCL4/PF4 enzyme-linked immunosorbent assay (ELISA) Kit. The levels of CSF Aβ42, Aβ40, p-tau181, and t-tau were measured on the fully-automated Lumipulse G1200 platform via commercially available kits.

RESULTS

The levels of serum PF4 were significantly decreased in AD patients (5163.51 (3198.24-6301.15) vs. 5859.29 (4126.06-8006.70), Z = -2.30, P = 0.021). The negative correlation between AD diagnosis (β = -1972.292, P = 0.009) and PF4 levels retained after the adjustments of age, sex, APOE ε4 status, platelet count, platelet distribution width (PDW), and comorbidity of dyslipidemia in the multiple linear regression analysis. Further analysis showed that serum PF4 levels were positively correlated with CSF Aβ42 levels and Mini-Mental State Examination (MMSE) scores, and negatively correlated with CSF t-tau levels. Besides, the area under the curve (AUC) of serum PF4 for AD (AUC = 0.6437, P = 0.022) was comparable to that of CSF Aβ40 (AUC = 0.6400) yet lower than those of CSF Aβ42, ptau181, and t-tau. The AUC slightly increased when combining serum PF4 with other CSF AD biomarkers separately.

CONCLUSIONS

The serum levels of PF4 were decreased in AD patients and were significantly correlated with the cognitive function and CSF levels of Aβ42 and t-tau. PF4 may become a promising anti-aging and therapeutic target for AD, which is worthy of further study.

Identification of the changes in the platelet proteomic profile of elderly individuals

Background

Platelet hyperreactivity is a risk factor for thrombosis in elderly patients with cardiovascular diseases. However, the mechanism of platelet hyperactivation has not been elucidated. This study aims to investigate alterations in the proteomes of platelets and their correlation with platelet hyperreactivity among elderly individuals.

Methods

This study included 10 young (28.1 ± 1.9 years), 10 middle-aged (60.4 ± 2.2 years), and 10 old (74.2 ± 3.0 years) subjects. Washed platelets were used in the present study. Platelet samples were analysed by using data-independent acquisition (DIA) quantitative mass spectrometry (MS).

Results

The results showed that the platelet proteomic profile exhibited high similarity between the young and middle-aged groups. However, there were significant differences in protein expression profiles between the old group and the young group. By exploring the dynamic changes in the platelet proteome with ageing, clusters of proteins that changed significantly with ageing were selected for further investigation. These clusters were related to the initial triggering of complement, phagosome and haemostasis based on enrichment analysis. We found that platelet degranulation was the major characteristic of the differentially expressed proteins between the old and young populations. Moreover, complement activation, the calcium signalling pathway and the nuclear factor-κB (NF-κB) signalling pathway were enriched in differentially expressed proteins.

Conclusions

The present study showed that there are obvious differences in the protein profiles of the elderly compared with young and middle-aged populations. The results provide novel evidence showing changes in platelet hyperactivity and susceptibility to thrombosis in the elderly population.

Relation of Mean Platelet Volume (MPV) with Cancer: A Systematic Review with a Focus on Disease Outcome on Twelve Types of Cancer

Inflammatory proteins activate platelets, which have been observed to be directly related to cancer progression and development. The aim of this systematic review is to investigate the possible association between Mean Platelet Volume (MPV) and cancer (diagnostic capacity of MPV, relation to survival, the severity of the disease, and metastasis). A literature review was performed in the online database PubMed and Google Scholar for the period of 2010–2022. In total, 83 studies including 21,034 participants with 12 different types of cancer (i.e., gastric cancer, colon cancer, esophageal squamous cell carcinoma, renal cancer, breast cancer, ovarian cancer, endometrial cancer, thyroid cancer, lung cancer, bladder cancer, gallbladder cancer, and multiple myeloma) were identified. The role of MPV has been extensively investigated in several types of cancer, such as gastric, colon, breast, and lung cancer, while few data exist for other types, such as renal, gallbladder cancer, and multiple myeloma. Most studies in gastric, breast, endometrium, thyroid, and lung cancer documented an elevated MPV in cancer patients. Data were less clear-cut for esophageal, ovarian, and colon cancer, while reduced MPV was observed in renal cell carcinoma and gallbladder cancer. Several studies on colon cancer (4 out of 6) and fewer on lung cancer (4 out of 10) indicated an unfavorable role of increased MPV regarding mortality. As far as other cancer types are concerned, fewer studies were conducted. MPV can be used as a potential biomarker in cancer diagnosis and could be a useful tool for the optimization of treatment strategies. Possible underlying mechanisms between cancer and MPV are discussed. However, further studies are needed to elucidate the exact role of MPV in cancer progression and metastasis.

Platelet Abnormalities in Children with Laboratory-Confirmed Influenza

BACKGROUND

The role of platelets in the immune response against influenza has been raised, and a diagnostic or prognostic value of platelet parameter abnormalities, including platelet count (PLT), or mean platelet volume (MPV), has been suggested. The study aimed to analyze the prognostic value of platelet parameters in children hospitalized due to laboratory-confirmed influenza.

METHODS

We retrospectively verified the platelet parameters (PLT, MPV, MPV/PLT, and PLT/lymphocyte ratio regarding the influenza complications (acute otitis media, pneumonia, and lower respiratory tract infection-LRTI), and the clinical course (antibiotic treatment, tertiary care transfer, and death).

RESULTS

An abnormal PLT was observed in 84 out of 489 laboratory-confirmed cases (17.2%, 44 thrombocytopaenia cases, and 40 thrombocytoses). Patients' age correlated negatively with PLT (rho = -0.46) and positively with MPV/PLT (rho = 0.44), while MPV was not age-dependent. The abnormal PLT correlated with increased odds of complications (OR = 1.67), including LRTI (OR = 1.89). Thrombocytosis was related to increased odds of LRTI (OR = 3.64), and radiologically/ultrasound-confirmed pneumonia (OR = 2.15), mostly in children aged under 1 year (OR = 4.22 and OR = 3.79, respectively). Thrombocytopaenia was related to antibiotic use (OR = 2.41) and longer hospital stays (OR = 3.03). A lowered MPV predicted a tertiary care transfer (AUC = 0.77), while MPV/PLT was the most versatile parameter in predicting LRTI (AUC = 0.7 in <1 yo), pneumonia (AUC = 0.68 in <1 yo), and antibiotic treatment (AUC = 0.66 in 1-2 yo and AUC = 0.6 in 2-5 yo).

CONCLUSIONS

Platelet parameters, including PLT count abnormalities and MPV/PLT ratio, are related to the increased odds of complications and a more severe disease course, and may add important data in assessing pediatric influenza patients, but should be interpreted cautiously due to age-related specificities.

Preoperative risk factors for deep vein thrombosis in knee osteoarthritis patients undergoing total knee arthroplasty

BACKGROUND

To analyze the risk factors for preoperative deep vein thrombosis (DVT) in knee osteoarthritis (OA) patients undergoing total knee arthroplasty (TKA).

METHODS

In this retrospective study, a total of 584 knee OA patients undergoing TKA were enrolled. General information, medical records and preoperative laboratory examination results of the patients were collected. According to the results of Doppler ultrasonography for the lower extremities, the patients were divided into DVT group and non-DVT group. Univariate and multivariate logistic regression were used to identify independent risk factors for preoperative DVT in knee OA patients undergoing TKA.

RESULTS

The incidence of DVT before TKA was 6.85% (40 cases). The increase of ESR (Erythrocyte Sedimentation Rate), platelet crit, IL-6 (Interleukin-6), and PCT (Procalcitonin) were associated with the development of DVT before TKA. Factors as coronary heart disease (CHD), diabetes mellitus (DM), Chronic Kidney Disease (CKD), NLR (ratio of neutrophils to lymphocytes), lower limb venous blood stasis, the time from onset to admission, RBC, PLT were identified by multivariate logistic regression to be the independent risk factors for preoperative DVT in knee OA patients undergoing TKA.

CONCLUSIONS

DM, CKD, CHD, increased in ESR, IL-6 and PCT, blood stasis of the lower extremities, increased in PLT, platelet crit and the time from onset to admission, decreased in RBC, were high risk factors for preoperative DVT in knee OA patients undergoing TKA.

Association Between Platelet Indices and Preoperative Deep Vein Thrombosis in Elderly Patients Undergoing Total Joint Arthroplasty: A Retrospective Study

To investigate the association between platelet (PLT) indices and preoperative deep vein thrombosis (DVT) in elderly patients undergoing total joint arthroplasty (TJA). A total of 1391 patients were enrolled. We created receiver operator characteristic (ROC) curve using the ratio of PLT indices to DVT before TJA, divided the enrolled patients into groups based on the cut-off value, and then analyzed risk factors for DVT before TJA in the multivariate binary logistic regression analysis. Preoperative DVT occurred in 103 cases. Based on the ROC curve, we determined that the cut-off values for PLT, mean platelet volume (MPV), platelet distribution width (PDW), platelet large cell ratio (P-LCR), and plateletcrit (PCT) were 202 × 109/L, 11.4 fL, 13.2 fL, 34.6%, and 0.228%. And the areas under the curve were 0.606, 0.605, 0.617, 0.616, and 0.598. Multivariate binary regression analysis revealed that the risk of preoperative DVT in TJA patients with PLT≥202 × 109/L, MPV≤11.4 fL, PDW≤13.2 fL, P-LCR≤34.6%, and PCT≥0.228% increased by 2.32 (P < .001, 95% confidence interval [CI] [1.50-3.60]), 1.86 (P < .001, 95% CI [1.22-2.83]), 2.17 (P < .001, 95% CI [1.43-3.31]), 2.27 (P < .001, 95% CI [1.50-3.45]), and 1.76 times (P = .013, 95% CI [1.13-2.76]), respectively. Age, P < .001, odds ratio (OR) = 1.08, 95% CI [1.04-1.11]; corticosteroid use, P = .011, OR = 3.66, 95% CI [1.34-9.96]. We found that increased PLT count and PCT, decreased MPV, PDW, and P-LCR, old age, and corticosteroid use were independent risk factors for preoperative DVT in elderly TJA patients.

The postpartum uterine ultrasonographic scale in assessment of uterine involution after cesarean section in treated thrombophilia pregnant patients at term

Background

Pregnancy is a prothrombotic condition which can be abnormally exaggerated in women with thrombophilia.

Methods

In a prospective study, patients who delivered at term, by cesarean section, between 1 October 2017 and 1 December 2021, who already had a diagnosis of thrombophilia before coming to our hospital, were included in the study group (n = 80). A similar number of nonthrombophilia patients (n = 80) without any history of thrombotic events, age‐ and para‐matched with the study group, were included in the control group. The postpartum uterine ultrasonographic scale (PUUS) values, in the first 24–48 h, were correlated with the patients' data.

Results

The P‐LCR (platelet large cell ratio), was significantly higher in the treated thrombophilia group (p = 0.042). There was no correlation between PUUS and complete blood count values, coagulation factors, maternal characteristics, or fetal outcomes, except for postpartum neutrophils (p = 0.047) and postpartum platelet count (p = 0.046).

Conclusions

Postpartum uterine involution was not significantly different, after cesarean section, between treated thrombophilia patients and nonthrombophilia patients. Involution correlated only with postpartum neutrophils and postpartum platelet count.

Impact of aging on immature platelet count and its relationship with coronary artery disease

Despite the fact that elderly patients represent a prevalent and challenging population in the current practice, few data exist on the impact of platelet parameters on cardiovascular risk in these patients. Therefore, the aim of the present study was to evaluate the impact of age on the immature platelet count (IPC) and their relationship with CAD. We included a total of 2236 consecutive patients undergoing coronary angiography in a single center. Elderly patients (age ≥ 75 years) were 756 (33.7%). IPC was measured at admission. Elderly patients were more often females (p < .001), with lower BMI and prevalence of smokers (p < .001), and a more complex cardiovascular risk profile and coronary disease (p = .02). Platelet count decreased with aging (p = .05), whereas no difference in the mean IPC was found between patients < or ≥75 years. In fact, advanced age did not emerge as an independent predictor of IPC above III tertile (≥8.6*10^6/ml), (adjusted OR[95%CI] = 0.97[0.78-1.21], p = .79). When considering elderly patients according to tertiles values of IPC (<5.1,5.1-8.59; ≥8.6*10^6/ml), we found no impact of IPC on the prevalence of CAD (81.1% vs 84.5% vs 81.5%, p = .92; adjusted OR[95%CI] = 1.08[0.67-1.72], p = .75) and its extent (37.7% vs 34.5% vs 40.2%, p = .57; adjusted OR[95%CI] = 1.22[0.85-1.73], p = .28). However, we observed a higher rate of calcified and type C lesions in elderly patients with higher IPC (p = .03 and p < .001, respectively). Therefore, advanced age is not associated with higher immature platelet count and the prevalence and severity of CAD. Moreover, IPC does not contribute to explain the higher prevalence and extent of coronary artery disease observed in elderly patients.

Altered functions of platelets during aging

PURPOSE OF REVIEW

Platelets are specialized effector cells that rapidly respond to sites of vascular injury. However, emerging data demonstrate that platelets possess diverse functions that also mediate inflammatory responses and neurological diseases. These functions are relevant to disease processes prevalent among older adults and likely influence susceptibility to thrombotic and inflammatory disorders.

RECENT FINDINGS

Platelet counts decrease in aged individuals whereas platelet reactivity increases. The platelet transcriptome is altered in aged individuals resulting in altered platelet function and exaggerated inflammation. Platelet signaling to monocytes in aging results in significantly more cytokines because of increased platelet-derived granzyme A. Platelet activation in aging appears to be driven, in part, because of increased reactive oxygen species and activation of the mammalian target of rapamycin pathway. Increased platelet hyperactivity in diseases is associated with aging, such cardiovascular disease and sepsis, exaggerate inflammation and thrombosis. Noncanonical functions of platelets influence the development of neurological diseases including Alzheimer's disease.

SUMMARY

Although there have been advances dissecting the molecular mechanisms regarding aging-related changes in platelets, many knowledge gaps still remain. Studies filling these gaps are likely to identify new mechanisms driving aging-related changes in platelet gene expression and function, and contributing to injurious thrombo-inflammation in older adults.

Influence of ABO Locus on PFA-100 Collagen-ADP Closure Time Is Not Totally Dependent on the Von Willebrand Factor. Results of a GWAS on GAIT-2 Project Phenotypes

(1) Background: In a previous study, we found that two phenotypes related to platelet reactivity, measured with the PFA-100 system, were highly heritable. The aim of the present study was to identify genetic determinants that influence the variability of these phenotypes: closure time of collagen-ADP (Col-ADP) and of collagen-epinephrine (Col-Epi). (2) Methods: As part of the GAIT-2 (Genetic Analysis of Idiopathic Thrombophilia (2) Project, 935 individuals from 35 large Spanish families were studied. A genome-wide association study (GWAS) with ≈ 10 M single nucleotide polymorphisms (SNPs) was carried out with Col-ADP and Col-Epi phenotypes. (3) Results: The study yielded significant genetic signals that mapped to the ABO locus. After adjusting both phenotypes for the ABO genotype, these signals disappeared. After adjusting for von Willebrand factor (VWF) or for coagulation factor VIII (FVIII), the significant signals disappeared totally for Col-Epi phenotype but only partially for Col-ADP phenotype. (4) Conclusion: Our results suggest that the ABO locus exerts the main genetic influence on PFA-100 phenotypes. However, while the effect of the ABO locus on Col-Epi phenotype is mediated through VWF and/or FVIII, the effect of the ABO locus on Col-ADP phenotype is partly produced through VWF and/or FVIII, and partly through other mechanisms.

Adverse factors responsible for below-normal platelet count after laparoscopic splenectomy and azygoportal disconnection

BACKGROUND/AIMS

Splenectomy is regarded as an effective curative treatment for thrombocytopenia caused by hypersplenism in patients with cirrhosis. However, in clinical practice, thrombocytopenia is not resolved by splenectomy in all patients. This study aimed to evaluate the adverse factors responsible for platelet (PLT) counts below the normal lower limit following laparoscopic splenectomy and azygoportal disconnection (LSD).

MATERIALS AND METHODS

We retrospectively evaluated the outcomes of 123 cirrhotic patients with portal hypertensive bleeding and secondary hypersplenism, who underwent LSD and who had PLT counts <125×109/L (non-normal group) or >125×109/L (normal group) at the postoperative month (POM) 3, between April 2014 and March 2017.

RESULTS

Sixteen patients (13.01%) had PLT counts <125×109/L at POM 3 after LSD, while the remaining 107 patients had normal counts. We analyzed 25 perioperative variables in both groups. A logistic multivariate regression identified age (relative risk [RR] 1.082, 95% confidence interval [CI] 1.018-1.150) and longitudinal spleen diameter (RR 0.977, 95% CI 0.955-1.000) as significant independent factors for the PLT count <125×109/L at POM 3. Bivariate correlation analysis showed that age >50 years and longitudinal spleen diameter <160 mm were threshold values for an increased risk of the PLT count <125×109/L at POM 3 after LSD.

CONCLUSION

Age was an independent positive predictor and longitudinal spleen diameter an independent negative predictor of PLT count <125×109/L at POM 3 after LSD.

Dose-response effects of omega-3 on platelet aggregation: an observational study

OBJECTIVE

This study aimed to evaluate the dose-response effects of supplemental omega-3 fatty acids on platelet function in healthy volunteers.

METHODS

Twelve healthy volunteers ingested a normal supplemental dose of 1260 mg omega-3 fatty acids daily for 5 days, followed by a high dose of 2520 mg daily for another 5 days. Multiple electrode aggregometry (MEA) with four different agonists was used to measure platelet aggregation before and after the normal- and high-dose regimes. In vitro spiking using physiological doses of omega-3 fatty acids was also performed to determine whether MEA is capable of detecting a platelet-inhibiting effect due to omega-3 fatty acids.

RESULTS

There were no differences in platelet aggregation measured by the MEA assay in healthy volunteers after intake of either the normal or high dose of omega-3 fatty acids. In the in vitro experiment, a platelet-inhibiting effect of omega-3 fatty acids was shown by an arachidonic acid agonist in MEA .

CONCLUSIONS

Supplemental omega-3 fatty acids do not evoke their positive health effects through inhibition of platelet aggregation measurable with MEA.

Short closure time values in PFA-100® are related to venous thrombotic risk. Results from the RETROVE Study

INTRODUCTION

Platelets play a role in the pathophysiology of venous thromboembolism (VTE). Some studies have not found an association between VTE and platelet aggregation. The PFA-100® analyser is an in vitro assay for assessing primary haemostasis. But, there are no studies to evaluate its association with VTE. We investigated the contribution of the global platelet function and aggregation in the development of VTE.

MATERIAL AND METHODS

We analysed 800 individuals who were included in the RETROVE Study (Riesgo de Enfermedad TROmboembólica VEnosa). Global platelet function was evaluated as closure times (CT) with the agonists ADP and epinephrine using a PFA-100® analyser. Platelet aggregation was evaluated by Multiplate™ analyser. The VTE risk for all the parameters was calculated by unconditional logistic regression analyses considering the potential confounders: age, gender, body mass index (BMI), factor VIII (FVIII), the von Willebrand factor (vWF) and the ABO blood group system.

RESULTS

The unadjusted odds ratio (OR) values ≤10th percentile for the PFAadp and PFAepi were 4.02 (95% CI, 2.76-5.95) and 3.33 (2.27-4.97). Also, after adjusting for vWF, we obtained lower OR for the PFAadp and for PFAepi: 2.24 (1.44-3.49) and 1.63 (1.04-2.59). But, the whole blood aggregation parameters did not shown an association with VTE risk.

CONCLUSION

We demonstrated an association between short CT and VTE risk. Although, the whole blood aggregation parameters did not show an association with the VTE risk. This striking contrast suggests that there are other platelet function mechanisms (e.g. adhesion) that are responsible of VTE risk.

Lack of association between platelet indices and disease stage in osteosarcoma at diagnosis

Purpose

The purpose of this study was to investigate the relationship between platelet indices [mean platelet volume (MPV), platelet count (PLT), platelet distribution width (PDW) and plateletcrit (PCT)] at diagnosis in osteosarcoma.

Methods

The information of 233 patients with osteosarcoma at diagnosis between 2007 and 2015 was retrospectively reviewed. Clinical parameters such as gender, age, size and site of tumor, and tumor necrosis rate after neoadjuvant chemotherapy were analyzed.

Results

No significant difference was noted in the mean values of MPV, PLT, PDW and PCT among stage I, II and III patients. In localized patients, the median disease-free survival (DFS) values were 42 and 22 months in the PLT<300×10⁹/L and ≥300×10⁹/L groups, respectively, but the difference was not statistically significant (P = 0.2611). No difference in the DFS among the three different levels of MPV was observed.

Conclusion

No significantly different platelet indices were noted among the different stages. Although a shorter median DFS was found in localized patients with PLT≥300×10⁹/L, there was still a lack of strong evidence to demonstrate the association between platelet indices and osteosarcoma.