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Background: Tylophorine (TYL) is an alkaloid with antiproliferative action in cancer cells. Vascular smooth muscle cell (VSMC) proliferation and neointima formation contribute to restenosis after percutaneous coronary interventions., Hypothesis/purpose: Our goal was to examine the potential of TYL to inhibit VSMC proliferation and migration, and to dissect underlying signaling pathways., Study Design and Methods: TYL was administered to platelet-derived growth factor (PDGF-BB)-stimulated, serum-stimulated, quiescent and unsynchronized VSMC of rat and human origin. BrdU incorporation and resazurin conversion were used to assess cell proliferation. Cell cycle progression was analyzed by flow cytometry of propidium iodide-stained nuclei. Expression profiles of proteins and mRNAs were determined using western blot analysis and RT-qPCR. The Click-iT OPP Alexa Fluor 488 assay was used to monitor protein biosynthesis., Results: TYL inhibited PDGF-BB-induced proliferation of rat aortic VSMCs by arresting cells in G1 phase of the cell cycle with an IC 50 of 0.13 µmol/l. The lack of retinoblastoma protein phosphorylation and cyclin D1 downregulation corroborated a G1 arrest. Inhibition of proliferation and cyclin D1 downregulation were species- and stimulus-independent. TYL also decreased levels of p21 and p27 proteins, although at later time points than observed for cyclin D1. Co-treatment of VSMC with TYL and MG132 or cycloheximide (CHX) excluded proteasome activation by TYL as the mechanism of action. Comparable time-dependent downregulation of cyclin D1, p21 and p27 in TYL- or CHX-treated cells, together with decreased protein synthesis observed in the Click-iT assay, suggests that TYL is a protein synthesis inhibitor. Besides proliferation, TYL also suppressed migration of PDGF-activated VSMC. In a human saphenous vein organ culture model for graft disease, TYL potently inhibited intimal hyperplasia., Conclusion: This unique activity profile renders TYL an interesting lead for the treatment of vasculo-proliferative disorders, such as restenosis., (Copyright © 2019 Elsevier GmbH. All rights reserved.)

Inhibition of vascular smooth muscle cell (VSMC) proliferation is of substantial interest in combating cardiovascular disease. A dichloromethane extract from the rhizomes of Peucedanum ostruthium, a traditionally used Austrian medicinal plant with anti-inflammatory properties, was examined for a putative antiproliferative activity in rat aortic VSMC. This extract inhibited serum (10%)-induced VSMC proliferation concentration dependently. Further identification and biological testing of its major constituents revealed that the coumarin ostruthin (7) is the major antiproliferative substance. In summary, a new bioactivity of P. ostruthium rhizomes is described, and 7 has been identified as the responsible compound.

Aims: Resveratrol (RV), an antioxidant, inhibits angiotensin II (Ang II)-induced hypertrophy and Ang II- or epidermal growth factor (EGF)-induced Akt phosphorylation in rat vascular smooth muscle cells (VSMCs). Both signalling pathways are reported to utilize reactive oxygen species (ROS). The aim of this study was to show whether RV reduces the ROS level in Ang II- or EGF-activated VSMCs and whether reduction of ROS causes the impeded signalling towards Akt in the presence of RV., Methods and Results: We show here that RV reduces intracellular ROS and extracellular H₂O₂ release from VSMCs as measured using 2',7'-dichlorodihydrofluorescein-diacetate and Amplex Red™. Since NADPH oxidases (Nox) 1 and 4 are major ROS sources in VSMCs, we examined their need for Akt phosphorylation in response to Ang II or EGF. Experiments using the blocking peptide gp91ds-tat verified a role for Nox1 in Ang II signalling towards Akt, but excluded a role for Nox1 in the respective EGF signalling. A small interfering RNA-mediated knock-down of Nox4 showed that Nox4 was not required for Ang II- or EGF-induced Akt phosphorylation. Use of the flavoprotein inhibitor diphenyleneiodonium, N-acetyl-cysteine, and non-antioxidant RV derivatives revealed that the antioxidant capacity of RV is not required for the inhibition of Akt phosphorylation, in both rat and human VSMCs., Conclusion: Thus, although RV acts as an antioxidant, the antihypertrophic response of RV in VSMCs and the signalling downstream of the EGF receptor towards Akt seem to be largely redox independent.

A low density of macular pigment may represent a risk factor for age-related macular degeneration (AMD) by permitting greater blue light damage. This study was carried out to determine the effects on macular pigment optical density of dietary supplementation with lutein, one of the pigment constituents. Two subjects consumed lutein esters, equivalent to 30 mg of free lutein per day, for a period of 140 days. Macular pigment optical density was determined by heterochromatic flicker photometry before, during, and after the supplementation period. Serum lutein concentration was also obtained through the analysis of blood samples by high-performance liquid chromatography. Twenty to 40 days after the subjects commenced taking the lutein supplement, their macular pigment optical density began to increase uniformly at an average rate of 1.13+/-0.12 milliabsorbance units/day. During this same period, the serum concentration of lutein increased roughly tenfold, approaching a steady state plateau. The optical density curve eventually levelled off 40 to 50 days after the subjects discontinued the supplement. During the same 40 to 50 days, the serum concentration returned to baseline. Thereafter, little or no decrease in optical density was observed. The mean increases in the macular pigment optical density were 39% and 21% in the eyes of the two subjects respectively. In conclusion, the modest period of supplementation has been estimated to have produced in the subjects a 30 to 40% reduction in blue light reaching the photoreceptors, Bruch's membrane, and the retinal pigment epithelium, the vulnerable tissues affected by AMD.