Methotrexate loaded SAE coated coronary stents reduce neointimal hyperplasia in a porcine coronary model

Methotrexate Therapy Promotes Cell Coverage and Stability in in-Stent Neointima

PURPOSE

Anti-proliferative drugs released from drug-eluting stents delay cell coverage and vascular healing, which increases the risk of late stent thrombosis. We assessed the potential effects of systemic methotrexate (MTX) on cell coverage, vascular healing and inflammation activation in vivo and in vitro.

METHODS

We applied MTX in the right common carotid artery in a rabbit stenting model to determine the impact on cell coverage and inflammation activation using a serial optical coherence tomography (OCT) analysis and elucidated the molecular mechanism of MTX in human umbilical vein endothelial cells (HUVECs).

RESULTS

Low-dose MTX promoted the development of cell coverage and vascular healing, which was associated with fewer uncovered struts (%) and cross-sections with any uncovered struts (%) at 4 weeks of stenting. The MTX group also exhibited lower rates of heterogeneity, microvessels and per-strut low-signal-intensity layers, indicating neointimal instability at 12 weeks of stenting. In vitro, low-dose MTX strongly inhibited HUVEC apoptosis, promoted proliferation and inhibited inflammatory activation by targeting the phosphoinositide 3-kinase (PI3K)/AKT signalling pathway.

CONCLUSION

Low-dose MTX may be a key means of promoting early cell coverage via the inhibition of the inflammatory response and stability of neointima by targeting inflammatory pathways after stent implantation.

Effects of Methotrexate in a Rabbit Model of In-Stent Neoatherosclerosis: An Optical Coherence Tomography Study

This study used optical coherence tomography (OCT) to investigate the effects of systemic methotrexate, in combination with a drug-eluting stent, on in-stent neoatherosclerosis in a rabbit model. Sirolimus-eluting stents were surgically implanted in the right common carotid arteries of 200 male New Zealand White rabbits; the animals received a high-fat diet, beginning one week before stent implantation. Each animal was randomly assigned to 1 of 4 groups, receiving intravenous injections of either methotrexate (0.4 mg/kg) or placebo weekly for 4 or 12 weeks. Stented arterial segments were harvested after stenting for 4 or 12 weeks, and processed for OCT and histological analysis. Prior to harvesting the arterial segments, blood was collected for the determinations of cytokine levels. Compared with the control animals, the methotrexate-treated animals showed lower rates of lipid-rich intima and per-strut low-signal intensity layers, smaller neointimal areas, and reduced neointimal thickness; larger fibrous cap thicknesses and smaller lumen areas were also seen in the animals receiving methotrexate. The levels of serum interleukin, adhesion molecules, and nuclear factor-κB p65 decreased and IL-10 level increased in the methotrexate-treated animals. Targeting the pro-inflammatory pathways may be an effective way to prevent restenosis without the long-term risk of late thrombosis.

Percutaneous Coronary Intervention: Safety of Methotrexate and Its Possible Benefits on Restenosis After Bare-Metal Stent Deployment

Background

Percutaneous coronary intervention (PCI) revolutionized treatment of coronary artery disease. Drug-eluting stents are effective and safe but their cost is high, especially for some countries. The primary objective was to evaluate the safety of methotrexate (MTX) in patients who underwent PCI and the secondary goal was to evaluate the possibility that MTX has an impact on restenosis.

Methods

This was a transversal, prospective and descriptive study that recruited 16 patients in whom PCI was planned. MTX was administered to patients at a dose of 5 mg/week for 2 weeks before PCI and 8 weeks after PCI. Bare-metal stent (BMS) deployment was performed according to standard practice. Patients were monitored clinically every 15 days during the first 2 months after the procedure and monthly until 9 months after PCI.

Results

There were no immediate or late complications associated with PCI. Adverse events and side effects due to MTX occurred in three patients (prevalence 18.7%). These side effects are classified as minor complications. MTX was not discontinued due to these side effects. There were no reported cases of clinical restenosis.

Conclusions

MTX was safe in the study population and raised the possibility that a low-cost drug may have positive effects on restenosis after BMS implantation. However, studies with larger sample sizes and other imagine modalities (intravascular ultrasound and/or optical coherence tomography) are required to confirm this hypothesis.

Magnetic chondroitin targeted nanoparticles for dual targeting of montelukast in prevention of in-stent restenosis

Magnetic nanoparticles and sodium montelukast encapsulated in rosin gum nanoparticles were targeted by chondroitin sulfate coated on their surface. They showed adhesion to endothelial cells and efficiently suppressed the VCAM-1 expression.

Most important chronic complications of arteriovenous fistulas for hemodialysis

The aim of this review was to highlight the most important complications of arteriovenous fistulas (AVFs) for hemodialysis (HD). The quality of vascular access for HD should be suitable for repeated puncture and allow a high blood flow rate for high-efficiency dialysis with minimal complications. The dialysis staff must be well versed in manipulation of the AVF, and there should be a minimal need for corrective interventions. Construction of an AVF creates conditions for increasing the flow of blood through the venous system. Fulfillment of these conditions reduces the risk of turbulence and endothelium injury, which, in turn, minimizes the potential for stenosis. An AVF is closest to the ideal model of vascular access. The most important complications of fistulae for HD are lymphedema, infection, aneurysm, stenosis, congestive heart failure, steal syndrome, ischemic neuropathy and thrombosis. In HD patients, the most common cause of vascular access failure is neointimal hyperplasia. It is important to gain information about early clinical symptoms of AVF dysfunction in order to prevent and adequately treat potential complications.

[Early pathohistological changes in dysfunction of arteriovenous fistula for hemodialysis]

BACKGROUND

In hemodialysis patients the most common cause of vascular access failure is neointimal hyperplasia of vascular smooth muscle cells at the venous anastomosis of arteriovenous fistulas.

CASE REPORT

We presented a 76-year old patient who had developed fistula thrombosis without the presence of known risk factors the eighth day after the initial function. A histopathological finding pointed to a significant rate of neointimal proliferation, as an initial reasons for the fistula stenosis and trombosis.

CONCLUSION

Early pathohistological changes observed in arteriovenous fistula dysfunction are response to hemodynamic changed conditions.

Drug-coated Stents

Since its introduction in 1977, the success of percutaneous interventional cardiology has been limited by the occurrence of restenosis. Drug-eluting stents, particularly sirolimus- and paclitaxel-coated stents, have been shown in randomized controlled trials to dramatically reduce restenosis in single, de novo, native coronary arteries. Over the last 2 years, investigators have reported that these stents can also reduce restenosis in more complex patient situations such as in diabetics, during acute coronary syndromes, in long atherosclerotic lesions and small arteries, and even after in-stent restenosis. These outcomes increase the clinical value of this technology to "real world" practice. This article reviews the current state of our knowledge regarding drug-eluting stents and identifies areas for further research.