Plasma concentrations of soluble CD40 ligand in smokers with acute myocardial infarction: a pilot study

Differential Responsiveness of the Platelet Biomarkers, Systemic CD40 Ligand, CD62P, and Platelet-Derived Growth Factor-BB, to Virally-Suppressive Antiretroviral Therapy

Systemic biomarkers of inflammation, including cytokines and chemokines, are potentially useful in the management of both HIV infection and non-AIDS-defining disorders. However, relatively little is known about the utility of measurement of circulating biomarkers of platelet activation as a strategy to monitor the efficacy of combination antiretroviral therapy (cART), as well as the persistence of systemic inflammation following virally-suppressive therapy in HIV-infected persons. These issues have been addressed in the current study to which a cohort consisting of 199 HIV-infected participants was recruited, 100 of whom were cART-naïve and the remainder cART-treated and virally-suppressed. Fifteen healthy control participants were included for comparison. The study focused on the effects of cART on the responsiveness of three biomarkers of platelet activation, specifically soluble CD40 ligand (sCD40L), sCD62P (P-selectin), and platelet-derived growth factor-BB (PDGF-BB), measured using multiplex suspension bead array technology. Most prominently sCD40L in particular, as well as sCD62P, were significantly elevated in the cART-naïve group relative to both the cART-treated and healthy control groups. However, levels of PDGF-BB were of comparable magnitude in both the cART-naïve and -treated groups, and significantly higher than those of the control group. Although remaining somewhat higher in the virally-suppressed group relative to healthy control participants, these findings identify sCD40L, in particular, as a potential biomarker of successful cART, while PDGF-BB may be indicative of persistent low-level antigenemia.

Evaluation of plasma levels of neopterin and soluble CD40 ligand in patients with acute ischemic stroke in upper Egypt: can they surrogate the severity and functional outcome?

BACKGROUND

Inflammation constitutes a major component of ischemic stroke pathology. The prognostic value of "neopterin" and soluble CD40 ligand (sCD40L), as a potential biomarker of ischemic stroke, has been less extensively studied.

OBJECTIVES OF THE STUDY

This study aims at assessing the serum levels of neopterin and sCD40L in acute ischemic stroke (AIS), to clarify its association with the severity, etiology, and risk factors of stroke, and to evaluate their relationship with the stroke functional outcome in our study sample within 90 days of follow-up.

STUDY SAMPLE

This case-control study was conducted on 100 patients with first-ever acute onset ischemic stroke and 25 control subjects.

METHODS

Participants were subjected to full history taking and detailed clinical and neurological examination. Brain imaging was performed after hospital admission. Blood tests were drawn for assessment of neopterin and sCD40L on the first day of admission.

RESULTS

High levels of neopterin and sCD40L was reported. Their levels were significantly higher in relation with survival status. There was a relationship between AIS and sCD40L levels and the severity of the stroke. Within 3 months of follow-up, these biomarkers were associated significantly with poor functional outcome, within a 90-day follow-up period, and mortality. These biomarkers were highly associated in patients with small vessel occlusion as an etiology for AIS.

CONCLUSION

Neopterin and sCD40L levels increased after AIS. Both biomarkers were strong and independent predictors of 90-day unfavorable clinical outcome and death in patients after AIS.

Anti-inflammatory and antithrombotic effects of nicotine exposure in oral contraceptive-induced insulin resistance are glucocorticoid-independent

BACKGROUND

Reports showed that estrogen-progestin oral contraceptive (COC) or tobacco smoking causes increased risk of cardiovascular diseases (CVD) in premenopausal women. Studies also suggest that nicotine, a major tobacco alkaloid, may worsen or improve atherothrombotic CVD. Altered hemorheology, prothrombotic and pro-inflammatory biomarkers, have been implicated in the development of atherothrombotic CVD events. However, the effect of non-smoking nicotine exposure on these biomarkers during COC treatment is not yet established. We therefore sought to determine the effects of nicotine exposure during COC treatment on these biomarkers, and also tested the hypothesis that the nicotine effects would be glucocorticoid-dependent.

METHODS

Female Sprague-Dawley rats aged 10 weeks were given (po) vehicle, low-dose nicotine (0.1mg/kg) or high-dose nicotine (1.0mg/kg) with or without COC steroids (5.0μg/kg ethinylestradiol and 25.0μg/kg levonorgestrel) daily for 6 weeks.

RESULTS

COC treatment or nicotine exposure led to increased insulin resistance (IR), hemorheological (blood viscosity, hematocrit and plasma viscosity), prothrombotic (plasminogen activator inhibitor-1), pro-inflammatory (uric acid, C-reactive protein, neutrophil/lymphocyte and platelet/lymphocyte ratios) biomarkers and corticosterone. However, these effects except that on corticosterone were abrogated by nicotine exposure during COC treatment.

CONCLUSIONS

Our study indicates that nicotine- or COC-induced IR may be mediated via inflammatory/thrombotic pathway. The results imply that nicotine exposure could impact negatively on atherothrombotic biomarkers in COC non-users, whereas the impact in COC users could be positive. The results also suggest that the anti-inflammatory, antithrombotic and blood viscosity-lowering effects of nicotine exposure during COC use is circulating glucocorticoid-independent.

Pooled Analysis Comparing the Efficacy of Intracoronary Versus Intravenous Abciximab in Smokers Versus Nonsmokers Undergoing Primary Percutaneous Coronary Revascularization for Acute ST-Elevation Myocardial Infarction

Cigarette smokers with ST-segment elevation myocardial infarction (STEMI) may present different response to potent antithrombotic therapy compared to nonsmokers. We assessed the impact of smoking status and intracoronary abciximab in patients with STEMI undergoing primary percutaneous coronary intervention (PCI). We pooled data from 5 randomized trials comparing intracoronary versus intravenous abciximab bolus in patients undergoing primary PCI. The primary end point was the composite of death or reinfarction at a mean follow-up of 292 ± 138 days. Of 3,158 participants, 1,369 (43.3%) were smokers, and they had a lower risk of the primary end point in crude, but not in adjusted analyses (hazard ratio [HR] 0.87, 95% confidence interval [CI] 0.63 to 1.21, p = 0.405). Intracoronary versus intravenous abciximab was associated with a significant reduction in the risk of primary end point among smokers (3.6% vs 8.0%; HR 0.43, 95% CI 0.26 to 0.72, p = 0.001), but not in nonsmokers (10.2% vs 9.9%; HR 0.99, 95% CI 0.72 to 1.36, p = 0.96), with a significant interaction (p = 0.009). Furthermore, intracoronary abciximab decreased the risk of reinfarction in smokers (HR 0.30, 95% CI 0.15 to 0.62, p = 0.001), with no difference in nonsmokers (HR 1.20, 95% CI 0.71 to 2.01, p = 0.50). Stent thrombosis was lowered by intracoronary abciximab in smokers (HR 0.28, 95% CI 0.06 to 0.66, p = 0.009), but was ineffective in nonsmokers (HR 1.04, 95% CI 0.54 to 2.00, p = 0.903). Interaction testing showed heterogeneity in treatment effect for reinfarction (p = 0.002) and stent thrombosis (p = 0.018) according to smoking status. In conclusion, among patients with STEMI undergoing primary PCI, smoking status did not affect the adjusted risk of clinical events. Intracoronary abciximab bolus improved clinical outcomes by reducing the risk of death or reinfarction.

Monocyte CD40 expression in young healthy female smokers and/or oral contraceptives users without additional risk factors for atherosclerosis

OBJECTIVE

Atherosclerosis, as an inflammatory disease, is characterized by pathologically altered levels of cytokines. We investigated whether smoking and/or oral contraceptives (OCs) affect the CD40/CD40L plasma levels and expression in young females without other risk factors for atherosclerosis.

PATIENTS AND METHODS

A case-control single-center design was used. Expression levels of CD40/CD40L were analyzed in healthy non-pregnant, pre-menopausal, non-smoking women who did not take OCs (n=49), women who currently smoke and take OCs (n=40), and women who are only smokers (n=40) or currently take OCs (n=42).

RESULTS

In OC users, there was a significant increase in CD40 mRNA expression in circulating monocytes as compared with smokers and control group. However, there were no significant differences in CD40 mRNA expression in monocytes between smokers and non-smokers. Interestingly, CD40 mRNA expression in women taking OCs and currently smoking was significantly decreased compared to only OC users (p<0.001). With regard to plasma CD40 levels there were significant differences between OC-users and control group. However, contrary to our expectations, there were no significant differences in expression levels of CD40L between four groups. In vitro experiments demonstrated enhanced CD40 mRNA and surface expression in human monocyte-derived macrophages stimulated with estrogens. Furthermore, nicotine pretreatment led to a suppression of estrogens stimulated CD40 induction.

CONCLUSIONS

In young healthy females without additional risk factors for atherosclerosis, OCs, but not smoking, are associated with dramatic changes in CD40 gene and plasma levels. These findings may be providing an important link between OCs and enhancement of pro-inflammatory and atherothrombotic conditions in healthy women.

PPARγ ligands decrease hydrostatic pressure-induced platelet aggregation and proinflammatory activity

Hypertension is known to be associated with platelet overactivity, but the direct effects of hydrostatic pressure on platelet function remain unclear. The present study sought to investigate whether elevated hydrostatic pressure is responsible for platelet activation and to address the potential role of peroxisome proliferator-activated receptor-γ (PPARγ). We observed that hypertensive patients had significantly higher platelet volume and rate of ADP-induced platelets aggregation compared to the controls. In vitro, Primary human platelets were cultured under standard (0 mmHg) or increased (120, 180, 240 mmHg) hydrostatic pressure for 18 h. Exposure to elevated pressure was associated with morphological changes in platelets. Platelet aggregation and PAC-1 (the active confirmation of GPIIb/IIIa) binding were increased, CD40L was translocated from cytoplasm to the surface of platelet and soluble CD40L (sCD40L) was released into the medium in response to elevated hydrostatic pressure (180 and 240 mmHg). The PPARγ activity was up-regulated as the pressure was increased from 120 mmHg to 180 mmHg. Pressure-induced platelet aggregation, PAC-1 binding, and translocation and release of CD40L were all attenuated by the PPARγ agonist Thiazolidinediones (TZDs). These results demonstrate that platelet activation and aggregation are increased by exposure to elevated pressure and that PPARγ may modulate platelet activation induced by high hydrostatic pressure.

Study of association of CD40-CD154 gene polymorphisms with disease susceptibility and cardiovascular risk in Spanish rheumatoid arthritis patients

Objective

Rheumatoid arthritis (RA) is a chronic inflammatory disease associated with increased cardiovascular (CV) mortality. Since CD40-CD154 binding has direct consequences on inflammation process initiation, we aimed to replicate previous findings related to disease susceptibility in Spanish RA population. Furthermore, as the major complication in RA disease patients is the development of CV events due to accelerated atherosclerosis, and elevated levels of CD40L/CD154 are present in patients with acute myocardial infarction, we assessed the potential association of CD40 and CD154/CD40L gene variants with CV risk in Spanish RA patients.

Methods

One thousand five hundred and seventy-five patients fulfilling the 1987 ACR classification criteria for RA and 1600 matched controls were genotyped for the CD40 rs1883832, rs4810485 and rs1535045 and CD154 rs3092952 and rs3092920 gene polymorphisms, using predesigned TaqMan single nucleotide polymorphism genotyping assays. Afterwards, we investigated the influence of CD40-CD154 gene variants in the development of CV events. Also, in a subgroup of 273 patients without history of CV events, we assessed the influence of these polymorphisms in the risk of subclinical atherosclerosis determined by carotid ultrasonography.

Results

Nominally significant differences in the allele frequencies for the rs1883832 CD40 gene polymorphism between RA patients and controls were found (p = 0.038). Although we did not observe a significant association of CD40-CD154 gene variants with the development of CV events, an ANCOVA model adjusted for sex, age at the time of the ultrasonography assessment, follow-up time, traditional CV risk factors and anti-cyclic citrullinated peptide antibodies disclosed a significant association (p = 0.0047) between CD40 rs1535045 polymorphism and carotid intima media thickness, a surrogate marker of atherosclerosis.

Conclusion

Data from our pilot study indicate a potential association of rs1883832 CD40 gene polymorphism with susceptibility to RA. Also, the CD40 rs1535045 gene variant may influence development of subclinical atherosclerosis in RA patients.

Platelet and monocyte activity markers and mediators of inflammation in Takotsubo cardiomyopathy

Patients with Takotsubo cardiomyopathy (TC) often present with symptoms similar to those of myocardial infarction (MI). We analyzed blood concentrations of mediators of inflammation and platelet- and monocyte-activity markers in patients with TC and MI for significant differences. Clinical data of patients with TC (n = 16) and acute MI (n = 16) were obtained. Serial blood samples were taken at the time of hospital admission (t(0)), after 2-4 days (t(1)) and after 4-7 weeks (t(2)), respectively. Plasma concentrations of interleukin (IL)-6, IL-7, soluble CD40 ligand (sCD40L), and monocyte chemotactic protein 1 (MCP-1) were determined with an ELISA. Tissue factor binding on monocytes, platelet-activation marker CD62P, platelet CD40-ligand (CD40L), and platelet-monocyte aggregates were measured using flow cytometry. Expression of CD62P on platelets and IL-6 plasma levels were significantly lower in patients with TC compared to MI at the time of hospital admission. IL-7 plasma levels were significantly elevated in patients with TC compared to patients with MI at 2-4 days after hospital admission. No significant differences were observed concerning sCD40L and MCP-1 plasma levels, tissue factor binding on monocytes, CD40L expression on platelets, and platelet-monocyte aggregates at any point in time. Our results indicate that inflammatory mediators and platelet-activity markers contribute to the differences in the pathogenesis of MI and TC.