Clotrimazole inhibits smooth muscle cell proliferation and has a vasodilator effect on resistance arteries

PRP significantly promotes the adhesion and migration of vascular smooth muscle cells on stent material

BACKGROUND

The adhesion and survival state of cells on scaffold material is a major problem in tissue-engineered blood vessel (TEBV) culture. Platelet-rich plasma (PRP) contains a large amount of biologically active factors and fibrin, which is expected to play an important role in TEBV culture.

PURPOSE

To combine PRP with cells and scaffold material to promote cell adhesion and biological activity on the scaffold material.

METHODS

The adhesion status and migration of SMCs under the optimal concentration suitable for SMC growth and the optimal concentration of PRP were examined by scanning electron microscopy, HE staining, CCK-8 assays, qPCR, WB, and other experimental methods and compared with those under the conventional culture (20% FBS); finally, the effect of PRP on the deposition of ECM in vascular tissue engineering culture was verified by three-dimensional culture.

RESULTS

PRP at 20% is a suitable concentration for SMCs. Compared with the control group, the 20% PRP group had better migration, and the number of SMC adhesions was significantly higher than that of the control group. In addition, collagen deposition in the experimental group was significantly higher than that in the control group.

CONCLUSION

PRP (20%) can promote SMC adhesion, migration, and collagen deposition on the scaffold material.

The intermediate conductance calcium-activated potassium channel KCa3.1 regulates vascular smooth muscle cell proliferation via controlling calcium-dependent signaling

The intermediate conductance calcium-activated potassium channel KCa3.1 contributes to a variety of cell activation processes in pathologies such as inflammation, carcinogenesis, and vascular remodeling. We examined the electrophysiological and transcriptional mechanisms by which KCa3.1 regulates vascular smooth muscle cell (VSMC) proliferation. Platelet-derived growth factor-BB (PDGF)-induced proliferation of human coronary artery VSMCs was attenuated by lowering intracellular Ca(2+) concentration ([Ca(2+)]i) and was enhanced by elevating [Ca(2+)]i. KCa3.1 blockade or knockdown inhibited proliferation by suppressing the rise in [Ca(2+)]i and attenuating the expression of phosphorylated cAMP-response element-binding protein (CREB), c-Fos, and neuron-derived orphan receptor-1 (NOR-1). This antiproliferative effect was abolished by elevating [Ca(2+)]i. KCa3.1 overexpression induced VSMC proliferation, and potentiated PDGF-induced proliferation, by inducing CREB phosphorylation, c-Fos, and NOR-1. Pharmacological stimulation of KCa3.1 unexpectedly suppressed proliferation by abolishing the expression and activity of KCa3.1 and PDGF β-receptors and inhibiting the rise in [Ca(2+)]i. The stimulation also attenuated the levels of phosphorylated CREB, c-Fos, and cyclin expression. After KCa3.1 blockade, the characteristic round shape of VSMCs expressing high l-caldesmon and low calponin-1 (dedifferentiation state) was maintained, whereas KCa3.1 stimulation induced a spindle-shaped cellular appearance, with low l-caldesmon and high calponin-1. In conclusion, KCa3.1 plays an important role in VSMC proliferation via controlling Ca(2+)-dependent signaling pathways, and its modulation may therefore constitute a new therapeutic target for cell proliferative diseases such as atherosclerosis.

Effects of the antifungal antibiotic clotrimazole on human cardiac repolarization potassium currents

The antifungal antibiotic clotrimazole (CLT) shows therapeutic effects on cancer, sickle cell disease, malaria, etc. by inhibiting membrane intermediate-conductance Ca2+ -activated K+ channels (IKCa). However, it is unclear whether this drug would affect human cardiac K+ currents. The present study was therefore designed to investigate the effects of CLT on transient outward K+ current (Ito1), and ultra-rapid delayed rectifier K+ current (IKur) in isolated human atrial myocytes, and cloned hERG channel current (IhERG) and recombinant human cardiac KCNQ1/KCNE1 channel current (IKs) expressed in HEK 293 cells. It was found that CLT inhibited Ito1 with an IC50 of 29.5 microM, accelerated Ito1 inactivation, and decreased recovery of Ito1 from inactivation. In addition, CLT inhibited human atrial I(Kur) in a concentration-dependent manner (IC50 = 7.6 microM). CLT substantially suppressed IhERG (IC50 = 3.6 microM), and negatively shifted the activation conductance of IhERG. Moreover, CLT inhibited IKs (IC50 = 15.1 microM), and positively shifted the activation conductance of the current. These results indicate that the antifungal antibiotic CLT substantially inhibits human cardiac repolarization K+ currents including Ito1, IKur, IhERG, and IKs. However, caution is recommended when correlating the observed in vitro effects on cardiac ion currents to the clinical relevance.

Bradykinin receptor antagonists attenuate neointimal proliferation postangioplasty

Bradykinin has been linked to the development of restenosis in response to vascular injury. We therefore examined the effect of bradykinin on vascular smooth muscle cell growth and neointimal formation in organ culture. Bradykinin stimulated both RNA and DNA synthesis (by 175%) in smooth muscle cells from either porcine or human coronary arteries and increased cell number in a concentration-dependent manner. Both p42/44 mitogen-activated protein kinase (MAPK) and p38 kinase were also activated. Treatment with [Hyp(3),Tyr(Me)(8)]bradykinin, a B(2) receptor agonist, stimulated thymidine incorporation by 146%, whereas B(1)-selective Lys-des-Arg(9)-bradykinin had no effect. Addition of the B(2) antagonist HOE-140 reduced the stimulation by 56%, whereas B(1)-selective des-Arg-HOE-140 had no significant effect. Similarly, HOE-140 attenuated angioplasty-induced neointimal formation in organ culture with an efficacy approaching 100% inhibition. These experiments suggest that bradykinin promotes smooth muscle proliferation after vascular injury, presumably via B(2) receptor-dependent activation of MAPK family pathways, and may explain the negative outcome of angiotensin converting enzyme inhibitor therapy on restenosis in nonrodent models.