The relation between carotid plaque echogenicity and oxidative stress marker 8-iso-prostaglandin F2α

Urinary biomarkers of oxidative and nitrosative stress and the risk for incident stroke: a nested case-control study from a community-based cohort

BACKGROUND

Oxidative and nitrosative stress has suggested to be involved in the pathophysiology of cardiovascular diseases, but has unclear relationship with the risk for incident stroke.

METHODS

In this nested case-control study, cases consisted of 131 participants who were free of stroke at screening and experienced incident stroke during the follow-up period. Controls were 1:1 frequency-matched for age and sex. Baseline levels of urinary creatinine-indexed biomarkers were measured using liquid chromatography-tandem mass spectrometry, including 8-iso-prostaglandin F₂α (8-iso-PGF₂α), 4-hydroxynonenal conjugate with mercapturic acid, 8-hydroxydeoxyguanosine and 8-nitroguanine.

RESULTS

The levels of urinary 8-iso-PGF₂α in stroke cases were higher than in controls [median (interquartile range), 1.13 (2.23-4.36) μg/g creatinine versus 0.71 (1.34-3.02) μg/g creatinine, p=0.004]. After adjusting cardiovascular risk factors, the association remained that higher level of urinary 8-iso-PGF₂α entailed the greater risk for incident stroke [per 1 standard deviation increase in log-transformed value, adjusted odds ratio, 1.40; 95% confidence interval (CI), 1.06-1.85; p=0.005] with a significant increasing trend across its quartiles (p for trend=0.016). After adding urinary 8-iso-PGF₂α, the prediction model not only improved discrimination between participants with or without incident stroke (integrated discrimination improvement, 0.025; 95% CI, 0.006-0.045; p=0.005), but enhanced stroke risk stratification (net reclassification improvement, 19.8%; 95% CI, 4.6-35.1%; p=0.011). In contrast, the relationships were non-significant among the other three biomarkers.

CONCLUSIONS

Our findings demonstrated that urinary 8-iso-PGF₂α could be an independent biomarker of oxidative stress for prediction of the risk for incident stroke.

Preoperative prediction of macrophage infiltration by 3-D tomographic ultrasound in endoarterectomized carotid plaques in elderly patients

AIM

Assessment of plaque characteristics is important for the optimal treatment of carotid stenosis, particularly in elderly patients. Macrophage infiltration is reported to be involved in carotid plaque instability. However, immunohistochemical assessment of the detailed localization of macrophage infiltration in carotid plaques remains limited. We attempted to elucidate this using 3-D ultrasonography (3D-US). We compared findings of the detailed localization of macrophage infiltration with findings from the newly developed tomographic ultrasound imaging (TUI).

METHODS

We obtained specimens of carotid arteries from 18 patients undergoing carotid endarterectomy (CEA), and investigated the localization of macrophages and vascular smooth muscle cells. Their localization obtained from 11 patients was compared with their preoperative TUI findings.

RESULTS

We classified the localization of macrophage infiltration into four types: (i) focal infiltration in the thick fibrous cap (12 cases); (ii) subendothelial zonal infiltration (2 cases); (iii) peripheral infiltration around the lipid core (8 cases); and (iv) local infiltration near the shoulder of the fibrous cap (2 cases). Among them, preoperative TUI was available in 11 CEA cases for histological comparison. We identified two sites of focal macrophage infiltration that corresponded to local echogenic lesions without an acoustic shadow on TUI. The proliferation of smooth muscle cells failed to show an apparent echogenicity.

CONCLUSIONS

TUI could not only evaluate the morphological features, but also showed the two types of focal macrophage infiltration relevant to plaque instability as an echogenic focus. TUI carried out by 3D-US is an easily applicable and non-invasive method that is considered useful for evaluating carotid plaques in elderly patients.