Decreased D2-40 immunoreactivity in stored paraffin sections and methods for preserving it

Ectopic Expression of PCSK9 by Smooth Muscle Cells Contributes to Aortic Dissection

BACKGROUND

Acute aortic dissection (AAD) is a common disease among the elderly. Although several risk factors of AAD have been reported, the molecular mechanism underlying AAD development remains to be elucidated. Proprotein convertase subtilisin/kexin type 9 (PCSK9) increases low-density lipoprotein cholesterol levels in blood by preventing its clearance. Therefore, PCSK9 inhibition is a promising therapeutic approach to treat cardiovascular diseases (CVDs). The objective of this study was to elucidate the role of PCSK9 in the pathogenesis of AAD.

METHODS

We used fluorescence immunohistochemistry to assess PCSK9 expression in aortic tissues resected from 10 AAD patients and in the normal aorta from 5 autopsy samples as well as in spontaneously hyperlipidemic apolipoprotein E-deficient mice used as an experimental AD model.

RESULTS

We revealed a characteristic distribution pattern of PCSK9 in atherosclerotic plaques and the degenerated tunica media in AAD tissues, which was rarely observed in normal aortic tissues. Furthermore, PCSK9 was notably expressed around calcification areas formed by vascular smooth muscle cells, especially those of the synthetic phenotype. The results obtained in the animal model were consistent with PCSK9 expression in AAD tissues.

CONCLUSIONS

Our findings suggest that PCSK9 overexpression in the aorta may promote AAD. This study adds to the growing body of evidence supporting the use of PCSK9 inhibitors for the management of CVDs.

Bone morphogenetic protein-4 and bone morphogenetic protein receptors expressions in the adult rat eye

We investigated the expressions of bone morphogenetic protein-4 (BMP4) and its receptors, bone morphogenetic protein receptor IA (BMPRIA), bone morphogenetic protein receptor IB (BMPRIB) and bone morphogenetic protein receptor II (BMPRII) in the adult rat eye. Interesting differences in expression profile were observed between BMPRIA and BMPRIB in the retina. BMPRIA-like immunoreactivity (IR) was very intensely seen in the photoreceptor layer, while BMPRIB-IR was mainly observed in the other layers. In the cornea, BMP4, BMPRIA, BMPRIB and BMPRII-IRs were abundantly seen in the cell body of basal cells in the corneal epithelium, and endothelium. In the lens, BMP4, BMPRIA, BMPRIB and BMPRIIIRs were observed in epithelial cells, lens cortical fiber cells, however they were not seen in the capsule and the central region of the lens. In the iris and ciliary body, strong BMP4 and BMPRIB-IRs were observed in nonpigmented epithelium. These results suggest that different kinds of BMP signaling should be needed in different areas in the adult eye to keep the shapes, differentiation levels, and functions of various cells.