Leptin receptor is elevated in carotid plaques from neurologically symptomatic patients and positively correlated with augmented macrophage density

A, Differences in the level of ObR_long, ObR_common, vascular endothelial growth factor 165 (VEGF₁₆₅), and macrophage antigen complex-1 (Mac-1) messenger RNA (mRNA) expression between symptomatic (S, black bars) and asymptomatic (AS, gray bars) plaques were examined using real-time polymerase chain reaction analysis. For each gene, the mean transcript level ± standard error is presented at the top of the bar. Values are expressed in arbitrary units. B, Correlation graphs between ObR_long and VEGF₁₆₅ messenger mRNAs, and between ObR_long and Mac-1 mRNAs.

Immunohistochemical detection of the leptin receptor in symptomatic and asymptomatic carotid plaques. Expression of the leptin receptor was analyzed on paraffin sections through atherosclerotic lesions at the carotid bifurcation. Representative examples of findings in lesions from (A and B) 13 symptomatic patients and (C and D) 12 asymptomatic are shown. Arrows point to ObR-positive cells (red-brown signal). Inserts highlight differences in the signal intensity of ObR-positive cells lining the luminal border (compare A and C) or within the medial portion of the vessel (compare B and D). Scale bars, 25 μm. E, Quantitative analysis of the ObR-immunopositive area is presented with the standard error (error bars). The statistical significance after comparison of both groups using the t test is indicated in the graph.

Immunofluoresence analysis for von Willebrand factor (vWF) in symptomatic and asymptomatic carotid plaques. The presence of blood vessels is demonstrated in three different microscopic fields of carotid specimens from (A) one representative symptomatic patient and (B) one representative asymptomatic patient. The arrows show exemplary blood vessels. Each specimen was stained using fluorescein isothiocyanate-labeled vWF antibodies and counterstained with 4',6-diamidino-2-phenylindole (DAPI). Scale bars, 50 μm. Note that multiple blood vessels are present in specimens from both patient groups. C, Quantitative analysis of blood vessels comparing symptomatic with asymptomatic plaques is presented with the standard error (error bars). The Wilcoxon rank test used for this analysis revealed no statistically significant differences between the two groups.

Immunohistochemical detection of macrophages in symptomatic and asymptomatic plaques. The presence of CD68-immunopositive macrophages in paraffin sections through atherosclerotic carotid artery lesions was analyzed. Representative findings in lesions from (A and B) 13 symptomatic patients and (C and D) 12 asymptomatic patients are shown. Arrows point at CD68 antigen-positive cells (red-brown signal). Scale bars, 25 μm. E, Quantitative analysis of the CD68-immunopositive area is presented with the standard error (error bars). The statistical significance after comparison of both groups using the t test is indicated.