Platelets: a potential role in chronic respiratory diseases?

Relationship between systemic immune response index (SIRI) and COPD: a cross-sectional study based on NHANES 2007-2012

Although the link between inflammation and chronic obstructive pulmonary disease (COPD) is increasingly recognized, the correlation between systemic immune response index (SIRI), a novel marker of inflammation, and COPD is unknown. This cross-sectional study used data from patients with complete lung function in NHANES 2007-2012 to explore the relationship between SIRI and COPD. We performed a series of statistical analyses on a total of 5056 participants, including multiple linear regression, smoothed curve fitting, ROC curve analysis, and subgroup analysis. In the fully corrected model, the logistic multiple regression showed that SIRI was associated with a high risk of COPD (OR1.350, 95% CI:1.220,1.493). The ROC curve showed that SIRI (AUC = 0.596) was significantly more efficient than other inflammatory factors in predicting COPD. Smoothed curve fit effect and threshold effect analyses showed a linear correlation between SIRI COPD prevalence, and subgroup analyses showed that the effect of SIRI on COPD was more pronounced in still smokers (OR 1.58, 95% CI: 1.34, 1.86) versus men (OR 1.62, 95% CI: 1.44, 1.83). The results of the interaction test provide evidence supporting SIRI as an independent risk factor for COPD.

Platelet and IL-33 count as biomarkers for lung function impairment: An 11-year follow-up study on populations exposed to hexavalent chromium

Recent research has highlighted the crucial role of immune regulation in lung function impairment due to exposure to hazardous materials. This study aimed to identify dynamic network biomarkers for lung function damage caused by hexavalent chromium inhalation exposure, using immune-related indicators in blood. An 11-year follow-up longitudinal study was conducted on a population occupationally exposed to hexavalent chromate (Cr [VI]) from 2010 to 2020, consisting of sixty-one subjects with 328 repeat measurements. Quantitative analysis of immune-related indicators, including white blood cells, cytokines, and platelet count, was performed. The concentration of urinary Cr served as an indicator of internal exposure, confirming its association with lung function impairment. Dynamic network analysis revealed that platelet count was connected to neutrophils, IL-8, IL-6, and IL-33 when the exposure time was equal to or longer than 9.2 years (the median exposure time). Notably, the association between platelet count and IL-33 was specific to long-term (≥ 9.2 years) exposure. The areas under the receiver operating characteristic (ROC) curves (AUCs) for platelet count combined with IL-33 to predict lung function impairment in the long-term and short-term Cr [VI]-exposed populations were 80.5 % and 55.4 %, respectively. These findings provide evidence that the combination of platelets and IL-33 holds significant promise as biomarkers for predicting lung function impairment. Moreover, they shed light on the potential mechanism involving immune and hematopoiesis functions in the context of environmental hazardous exposure.

Research progress of megakaryocytes and platelets in lung injury

The lung is an important site of extramedullary platelet formation, and megakaryocytes in the lung participate in immune responses in addition to platelet production. In acute lung injury and chronic lung injury, megakaryocytes and platelets play a promoting or protective role through different mechanisms. The authors reviewed the role of megakaryocytes and platelets in common clinical lung injuries with different course of disease and different pathogenic factors in order to provide new thinking for the diagnosis and treatment of lung injuries.

Seroprevalence and prognostic value of Aspergillus-specific IgG among non-neutropenic invasive pulmonary aspergillosis patients: a prospective multicenter study

BACKGROUND

This study aimed to assess the diagnostic and prognostic value of Aspergillus-specific IgG (Asp-IgG) for invasive pulmonary aspergillosis (IPA) in non-neutropenic non-hematologic patients.

METHODS

Between November 2019 and February 2022, we recruited 40 non-neutropenic, non-hematologic IPA patients from Taiwan and measured serum Asp-IgG levels using Phadia, Thermofisher. A positive Asp-IgG test was defined as a level > 40 mgA/L. We evaluated the association between Asp-IgG levels and overall survival, as well 90-day mortality rate of IPA patients.

RESULTS

Of the 40 participants, 11 (27.5%) tested positive for Asp-IgG, while 16 (40%) had positive galactomannan antigen (optical density > 1). Higher Asp-IgG levels were associated with improved overall survival (HR: 0.22, 95% CI: 0.05-0.99, p = 0.035) in multivariable Cox regression. The overall 90-day mortality rate was 65% (26/40). We found that patients with low Asp-IgG levels (≤ 40 mgA/L) had a borderline higher 90-day mortality rate compared to patients with high Asp-IgG levels (OR: 3.15, 95% CI: 0.75-13.28, p = 0.118). Stratifying by serum galactomannan and Aspergillus IgG levels, patients with elevated serum GM and low Asp-IgG had the highest 90-day mortality (80%, 8/10), followed by patients with low serum GM and low Asp-IgG (68.4%, 13/19).

CONCLUSIONS

Asp-IgG was positive in approximately one-fourth of non-neutropenic IPA patients. Asp-IgG may hold potential as a clinical prognostic factor for IPA. Further studies are required to validate this finding.

Associations of Platelet to High-Density Lipoprotein Cholesterol Ratio with Chronic Obstructive Pulmonary Disease: A Cross-Sectional Study from the US National Health and Nutrition Examination Survey

Background

The platelet to high-density lipoprotein cholesterol ratio (PHR) is a novel biomarker for inflammation and hypercoagulability. This study aimed to explore the potential association between PHR and prevalence of chronic obstructive pulmonary disease (COPD).

Methods

Participants aged between 40 and 85 years from the 1999-2018 US National Health and Nutrition Examination Survey with COPD were included. Multivariable logistic regression and restricted cubic spline analysis were applied to evaluate the associations between PHR and COPD. Propensity score matching (PSM) was performed to reduce the impact of potential confounding factors.

Results

A total of 25751 participants, including 753 with COPD, at a mean age of 57.19 years and 47.83% men, were included. The multivariable-adjusted model showed that the odds ratio (OR) and 95% confidence interval (CI) for PHR to predict COPD was 1.002 (1.001-1.003). Compared with the lowest quartile, the ORs and 95% CIs for the Q2, Q3, and Q4 PHR quartile were 1.162 (0.874-1.546), 1.225 (0.924-1.625), and 1.510 (1.102-2.069), respectively (P for trend = 0.012). Restricted cubic spline analysis demonstrated a linear association between PHR and COPD prevalence both before and after PSM. Significant association between PHR and COPD prevalence was observed only in participants without hypertension. Receiver-operating characteristic curves showed significantly higher area under the curve for distinguishing COPD from non-COPD by PHR than platelet count and high-density lipoprotein cholesterol.

Conclusion

PHR is significantly associated with COPD prevalence in US adults aged 40 to 85 years without hypertension, supporting the effectiveness of PHR as a potential biomarker for COPD.

Asthma and Cardiovascular Diseases: Navigating Mutual Pharmacological Interferences

Asthma and cardiovascular disease (CVD) often co-exist. When a patient has both conditions, management requires an approach that addresses the unique challenges of each condition separately, while also considering their potential interactions. However, specific guidance on the management of asthma in patients with CVD and on the management of CVD in patients with asthma is still lacking. Nevertheless, health care providers need to adopt a comprehensive approach that includes both respiratory and CVD health. The management of CVD in patients with asthma requires a delicate balance between controlling respiratory symptoms and minimising potential cardiovascular (CV) risks. In the absence of specific guidelines for the management of patients with both conditions, the most prudent approach would be to follow established guidelines for each condition independently. Careful selection of asthma medications is essential to avoid exacerbation of CV symptoms. In addition, optimal management of CV risk factors is essential. However, close monitoring of these patients is important as there is evidence that some asthma medications may have adverse effects on CVD and, conversely, that some CVD medications may worsen asthma symptoms. On the other hand, there is also increasing evidence of the potential beneficial effects of asthma medications on CVD and, conversely, that some CVD medications may reduce the severity of asthma symptoms. We aim to elucidate the potential risks and benefits associated with the use of asthma medications in patients with CVD, and the potential pulmonary risks and benefits for patients with asthma who are prescribed CVD medications.

Urinary eicosanoid levels in early life and risk of atopic disease in childhood

BACKGROUND

Eicosanoids are lipid mediators including thromboxanes (TXs), prostaglandins (PGs), and leukotrienes with a pathophysiological role in established atopic disease. However, their role in the inception of disease is unclear. This study aimed to investigate the association between urinary eicosanoids in early life and development of atopic disease.

METHODS

This study quantified the levels of 21 eicosanoids in urine from children from the COPSAC2010 (Copenhagen Prospective Studies on Asthma in Childhood 2010) (age 1 year, n = 450) and VDAART (Vitamin D Antenatal Asthma Reduction Trial) (age 3 years, n = 575) mother-child cohorts and analyzed the associations with development of wheeze/asthma, atopic dermatitis, and biomarkers of type-2 inflammation, applying false discovery rate of 5% (FDR5%) multiple testing correction.

RESULTS

In both cohorts, analyses adjusted for environmental determinants showed that higher TXA2 eicosanoids in early life were associated with increased risk of developing atopic dermatitis (P < FDR5%) and type-2 inflammation (P < .05). In VDAART, lower PGE2 and PGI2 eicosanoids and higher isoprostanes were also associated with increased risk of atopic dermatitis (P < FDR5%). For wheeze/asthma, analyses in COPSAC2010 showed that lower isoprostanes and PGF2 eicosanoids and higher PGD2 eicosanoids at age 1 year associated with an increased risk at age 1-10 years (P < .05), whereas analyses in VDAART showed that lower PGE2 and higher TXA2 eicosanoids at age 3 years associated with an increased risk at 6 years (P < FDR5%).

CONCLUSIONS

This study suggests that early life perturbations in the eicosanoid metabolism are present before the onset of atopic disease in childhood, which provides pathophysiological insight in the inception of atopic diseases.

Cell-Free DNA Maps Tissue Injury and Correlates with Disease Severity in Lung Transplant Candidates

Rationale: Plasma cell-free DNA levels correlate with disease severity in many conditions. Pretransplant cell-free DNA may risk stratify lung transplant candidates for post-transplant complications. Objectives: To evaluate if pretransplant cell-free DNA levels and tissue sources identify patients at high risk of primary graft dysfunction and other pre- and post-transplant outcomes. Methods: This multicenter, prospective cohort study recruited 186 lung transplant candidates. Pretransplant plasma samples were collected to measure cell-free DNA. Bisulfite sequencing was performed to identify the tissue sources of cell-free DNA. Multivariable regression models determined the association between cell-free DNA levels and the primary outcome of primary graft dysfunction and other transplant outcomes, including Lung Allocation Score, chronic lung allograft dysfunction, and death. Measurements and Main Results: Transplant candidates had twofold greater cell-free DNA levels than healthy control patients (median [interquartile range], 23.7 ng/ml [15.1-35.6] vs. 12.9 ng/ml [9.9-18.4]; P < 0.0001), primarily originating from inflammatory innate immune cells. Cell-free DNA levels and tissue sources differed by native lung disease category and correlated with the Lung Allocation Score (P < 0.001). High pretransplant cell-free DNA increased the risk of primary graft dysfunction (odds ratio, 1.60; 95% confidence interval [CI], 1.09-2.46; P = 0.0220), and death (hazard ratio, 1.43; 95% CI, 1.07-1.92; P = 0.0171) but not chronic lung allograft dysfunction (hazard ratio, 1.37; 95% CI, 0.97-1.94; P = 0.0767). Conclusions: Lung transplant candidates demonstrate a heightened degree of tissue injury with elevated cell-free DNA, primarily originating from innate immune cells. Pretransplant plasma cell-free DNA levels predict post-transplant complications.

Investigating the role of platelets and platelet-derived transforming growth factor-β in idiopathic pulmonary fibrosis

Transforming growth factor-β1 (TGFβ1) is the key profibrotic cytokine in idiopathic pulmonary fibrosis (IPF), but the primary source of this cytokine in this disease is unknown. Platelets have abundant stores of TGFβ1, although the role of these cells in IPF is ill-defined. In this study, we investigated whether platelets, and specifically platelet-derived TGFβ1, mediate IPF disease progression. Patients with IPF and non-IPF patients were recruited to determine platelet reactivity, and separate cohorts of patients with IPF were followed for mortality. To study whether platelet-derived TGFβ1 modulates pulmonary fibrosis (PF), mice with a targeted deletion of TGFβ1 in megakaryocytes and platelets (TGFβ1fl/fl.PF4-Cre) were used in the well-characterized bleomycin-induced pulmonary fibrosis (PF) animal model. In a discovery cohort, we found significantly higher mortality in patients with IPF who had elevated platelet counts within the normal range. However, our validation cohort did not confirm this observation, despite significantly increased platelets, neutrophils, active TGFβ1, and CCL5, a chemokine produced by inflammatory cells, in the blood, lung, and bronchoalveolar lavage (BAL) of patients with IPF. In vivo, we showed that despite platelets being readily detected within the lungs of bleomycin-treated mice, neither the degree of pulmonary inflammation nor fibrosis was significantly different between TGFβ1fl/fl.PF4-Cre and control mice. Our results demonstrate for the first time that platelet-derived TGFβ1 does not significantly mediate inflammation or fibrosis in a PF animal model. Furthermore, our human studies revealed blood platelet counts do not consistently predict mortality in IPF but other platelet-derived mediators, such as C-C chemokine ligand 5 (CCL5), may promote neutrophil recruitment and human IPF.NEW & NOTEWORTHY Platelets are a rich source of profibrotic TGFβ; however, the role of platelets in idiopathic pulmonary fibrosis (IPF) is unclear. We identified that patients with IPF have significantly more platelets, neutrophils, and active TGFβ in their airways than control patients. Using an animal model of IPF, we demonstrated that platelet-derived TGFβ does not significantly drive lung fibrosis or inflammation. Our findings offer a better understanding of platelets in both human and animal studies of IPF.

Cardiovascular diseases or type 2 diabetes mellitus and chronic airway diseases: mutual pharmacological interferences

Chronic airway diseases (CAD), mainly asthma and chronic obstructive pulmonary disease (COPD), are frequently associated with different comorbidities. Among them, cardiovascular disease (CVD) and type 2 diabetes mellitus (T2DM) pose problems for the simultaneous treatment of CAD and comorbidity. Indeed, there is evidence that some drugs used to treat CAD negatively affect comorbidity, and, conversely, some drugs used to treat comorbidity may aggravate CAD. However, there is also growing evidence of some beneficial effects of CAD drugs on comorbidities and, conversely, of the ability of some of those used to treat comorbidity to reduce the severity of lung disease. In this narrative review, we first describe the potential cardiovascular risks and benefits for patients using drugs to treat CAD and the potential lung risks and benefits for patients using drugs to treat CVD. Then, we illustrate the possible negative and positive effects on T2DM of drugs used to treat CAD and the potential negative and positive impact on CAD of drugs used to treat T2DM. The frequency with which CAD and CVD or T2DM are associated requires not only considering the effect that drugs used for one disease condition may have on the other but also providing an opportunity to develop therapies that simultaneously favorably impact both diseases.

Influence of the At-Arrival Host Transcriptome on Bovine Respiratory Disease Incidence during Backgrounding

Bovine respiratory disease (BRD) remains the leading disease within the U.S. beef cattle industry. Marketing decisions made prior to backgrounding may shift BRD incidence into a different phase of production, and the importance of host gene expression on BRD incidence as it relates to marketing strategy is poorly understood. Our objective was to compare the influence of marketing on host transcriptomes measured on arrival at a backgrounding facility on the subsequent probability of being treated for BRD during a 45-day backgrounding phase. This study, through RNA-Seq analysis of blood samples collected on arrival, evaluated gene expression differences between cattle which experienced a commercial auction setting (AUCTION) versus cattle directly shipped to backgrounding from the cow–calf phase (DIRECT); further analyses were conducted to determine differentially expressed genes (DEGs) between cattle which remained clinically healthy during backgrounding (HEALTHY) versus those that required treatment for clinical BRD within 45 days of arrival (BRD). A profound difference in DEGs (n = 2961) was identified between AUCTION cattle compared to DIRECT cattle, regardless of BRD development; these DEGs encoded for proteins involved in antiviral defense (increased in AUCTION), cell growth regulation (decreased in AUCTION), and inflammatory mediation (decreased in AUCTION). Nine and four DEGs were identified between BRD and HEALTHY cohorts in the AUCTION and DIRECT groups, respectively; DEGs between disease cohorts in the AUCTION group encoded for proteins involved in collagen synthesis and platelet aggregation (increased in HEALTHY). Our work demonstrates the clear influence marketing has on host expression and identified genes and mechanisms which may predict BRD risk.

Mobilisation of HLA-F on the surface of bronchial epithelial cells and platelets in asthmatic patients

Uncontrolled inflammation of the airways in chronic obstructive lung diseases leads to exacerbation, accelerated lung dysfunction and respiratory insufficiency. Among these diseases, asthma affects 358 million people worldwide. Human bronchial epithelium cells (HBEC) express both anti-inflammatory and activating molecules, and their deregulated expression contribute to immune cell recruitment and activation, especially platelets (PLT) particularly involved in lung tissue inflammation in asthma context. Previous results supported that HLA-G dysregulation in lung tissue is associated with immune cell activation. We investigated here HLA-F expression, reported to be mobilised on immune cell surface upon activation and displaying its highest affinity for the KIR3DS1-activating NK receptor. We explored HLA-F transcriptional expression in HBEC; HLA-F total expression in PBMC and HBEC collected from healthy individuals at rest and upon chemical activation and HLA-F membrane expression in PBMC, HBEC and PLT collected from healthy individuals at rest and upon chemical activation. We compared HLA-F transcriptional expression in HBEC from healthy individuals and asthmatic patients and its surface expression in HBEC and PLT from healthy individuals and asthmatic patients. Our results support that HLA-F is expressed by HBEC and PLT under healthy physiological conditions and is retained in cytoplasm, barely expressed on the surface, as previously reported in immune cells. In both cell types, HLA-F reaches the surface in the inflammatory asthma context whereas no effect is observed at the transcriptional level. Our study suggests that HLA-F surface expression is a ubiquitous post-transcriptional process in activated cells. It may be of therapeutic interest in controlling lung inflammation.

Platelets Purification Is a Crucial Step for Transcriptomic Analysis

Platelets are small anucleate cells derived from the fragmentation of megakaryocytes and are involved in different biological processes especially hemostasis, thrombosis, and immune response. Despite their lack of nucleus, platelets contain a reservoir of megakaryocyte-derived RNAs and all the machinery useful for mRNA translation. Interestingly, platelet transcriptome was analyzed in health and diseases and led to the identification of disease-specific molecular signatures. Platelet contamination by leukocytes and erythrocytes during platelet purification is a major problem in transcriptomic analysis and the presence of few contaminants in platelet preparation could strongly alter transcriptome results. Since contaminant impacts on platelet transcriptome remains theoretical, we aimed to determine whether low leukocyte and erythrocyte contamination could cause great or only minor changes in platelet transcriptome. Using microarray technique, we compared the transcriptome of platelets from the same donor, purified by common centrifugation method or using magnetic microbeads to eliminate contaminating cells. We found that platelet transcriptome was greatly altered by contaminants, as the relative amount of 8274 transcripts was different between compared samples. We observed an increase of transcripts related to leukocytes and erythrocytes in platelet purified without microbeads, while platelet specific transcripts were falsely reduced. In conclusion, serious precautions should be taken during platelet purification process for transcriptomic analysis, in order to avoid platelets contamination and result alteration.

Atypical Roles of the Chemokine Receptor ACKR3/CXCR7 in Platelet Pathophysiology

The manifold actions of the pro-inflammatory and regenerative chemokine CXCL12/SDF-1α are executed through the canonical GProteinCoupledReceptor CXCR4, and the non-canonical ACKR3/CXCR7. Platelets express CXCR4, ACKR3/CXCR7, and are a vital source of CXCL12/SDF-1α themselves. In recent years, a regulatory impact of the CXCL12-CXCR4-CXCR7 axis on platelet biogenesis, i.e., megakaryopoiesis, thrombotic and thrombo-inflammatory actions have been revealed through experimental and clinical studies. Platelet surface expression of ACKR3/CXCR7 is significantly enhanced following myocardial infarction (MI) in acute coronary syndrome (ACS) patients, and is also associated with improved functional recovery and prognosis. The therapeutic implications of ACKR3/CXCR7 in myocardial regeneration and improved recovery following an ischemic episode, are well documented. Cardiomyocytes, cardiac-fibroblasts, endothelial lining of the blood vessels perfusing the heart, besides infiltrating platelets and monocytes, all express ACKR3/CXCR7. This review recapitulates ligand induced differential trafficking of platelet CXCR4-ACKR3/CXCR7 affecting their surface availability, and in regulating thrombo-inflammatory platelet functions and survival through CXCR4 or ACKR3/CXCR7. It emphasizes the pro-thrombotic influence of CXCL12/SDF-1α exerted through CXCR4, as opposed to the anti-thrombotic impact of ACKR3/CXCR7. Offering an innovative translational perspective, this review also discusses the advantages and challenges of utilizing ACKR3/CXCR7 as a potential anti-thrombotic strategy in platelet-associated cardiovascular disorders, particularly in coronary artery disease (CAD) patients post-MI.