Comparative vascular responses three months after paclitaxel and everolimus-eluting stent implantation in streptozotocin-induced diabetic porcine coronary arteries

Drug-Coated Balloon-Oriented Angioplasty for Severe Symptomatic Atherosclerotic MCA Stenosis in Young Adults

Purpose

The clinical significance of endovascular therapy in young patients with symptomatic intracranial atherosclerotic stenosis is not clear. We aimed to report our preliminary findings on the safety and effectiveness of a new endovascular treatment strategy, drug-coated balloon (DCB)-oriented angioplasty for young adults with severe symptomatic atherosclerotic middle cerebral artery (MCA) stenosis.

Methods

We retrospectively retrieved the data of seven young patients aged 21–32 years old with severe symptomatic atherosclerotic MCA stenosis treated with DCB-oriented angioplasty from January 2018 to October 2020. We collected clinical presentations, perioperative complications, and clinical and radiological outcomes.

Results

The DCB was successfully dilated at the lesions in all seven patients and good antegrade perfusion was achieved in five. The other two patients underwent remedial stent implantation due to residual stenosis >50% and unstable antegrade perfusion after DCB dilatation. However, none of the patients had perioperative complications. There were no recurrent ischemic symptoms after a mean clinical follow-up period of 15.4 ± 6.9 months. Repeat vascular images of the patients showed no restenosis at 3- or 6-month imaging follow-up periods. High-resolution MRI (HRMRI) was completed in all the patients before the angioplasty procedure and at follow-up. Focal eccentric wall thickening was present at the site of stenosis preoperatively; however, the plaques had disappeared by the time of follow-up for all patients.

Conclusion

DCB-oriented angioplasty may be safe and effective for young patients with severe symptomatic atherosclerotic MCA stenosis.

Assessment of Vascular Patency and Inflammation with Intravascular Optical Coherence Tomography in Patients with Superficial Femoral Artery Disease Treated with Zilver PTX Stents

PURPOSE

Zilver PTX nitinol self-expanding drug-eluting stent with paclitaxel coating is effective for treatment of superficial femoral artery (SFA) disease. However, as with any stent, it induces a measure of vascular inflammatory response. The current clinical trial (NCT02734836) aimed to assess vascular patency, remodeling, and inflammatory markers with intravascular optical coherence tomography (OCT) in patients with SFA disease treated with Zilver PTX stents.

METHODS

Serial OCT examinations were performed in 13 patients at baseline and 12-month follow-up. Variables evaluated included neointimal area, luminal narrowing, thrombus area, stent expansion as well as measures of inflammation including, peri-strut low-intensity area (PLIA), macrophage arc, neovascularization, stent strut apposition and coverage.

RESULTS

Percentage of malapposed struts decreased from 10.3 ± 7.9% post-intervention to 1.1 ± 2.2% at 12-month follow-up, but one patient showed late-acquired stent malapposition (LASM). The percent of uncovered struts at follow-up was 3.0 ± 4.5%. Average expansion of stent cross-sectional area from baseline to follow-up was 35 ± 19%. The average neointimal area was 7.8 ± 3.8 mm². Maximal luminal narrowing was 61.1 ± 25.0%, and average luminal narrowing was 35.4 ± 18.2%. Average peri-strut low-intensity area (PLIA) per strut was 0.017 ± 0.018 mm². Average number of neovessels per mm of stent was 0.138 ± 0.181. Average macrophage angle per frame at follow-up was 7 ± 11°. Average thrombus area at follow-up was 0.0093 ± 0.0184 mm².

CONCLUSION

At 12-month follow-up, OCT analysis of Zilver PTX stent shows outward remodeling and minimal neointimal growth, but evidence of inflammation including PLIA, neovessels, thrombus and macrophages.

SUMMARY

Thirteen patients with PAD had paclitaxel-coated stents implanted in their SFAs and were then imaged with OCT at baseline and 12-month follow-up. OCT proxy metrics of inflammation were quantified.

Serial Morphological and Functional Assessment of the Paclitaxel-coated Balloon for de Novo Lesions

INTRODUCTION AND OBJECTIVES

There is limited data on the serial morphological and functional assessment of paclitaxel-coated balloon treatment using coronary angiography, optical coherence tomography, and fractional flow reserve.

METHODS

In this prospective, single-center observational study, patients with de novo lesions were treated with the paclitaxel-coated balloon. Serial angiographic, optical coherence tomography and fractional flow reserve measurements were performed before and after plain old balloon angioplasty, as well as at 9-month follow-up.

RESULTS

Twenty patients (21 lesions) were enrolled in this study. The reference vessel diameter was 2.68±0.34mm and late luminal loss was 0.01±0.21mm. The median changes in the minimal lumen area between pre- and postplain old balloon angioplasty, and postplain old balloon angioplasty and follow-up were an increase of 75.2% [interquartile range of 37.2 to 164.7] and 50.0% [interquartile range of 1.1% to 64.5%], respectively. Intimal dissections were seen in all postprocedural optical coherence tomography images, and 66.6% of them were sealed on follow-up optical coherence tomography (median 278 days). The fractional flow reserve distal to the target lesion was 0.71±0.14 predilatation, 0.87±0.04 postdilatation, and 0.83±0.08 at follow-up.

CONCLUSIONS

The paclitaxel-coated balloon restores coronary blood flow by means of plaque modification, causing an increment in minimal lumen area. At 9-month follow-up, coronary flow was sustained and the luminal patency was the result of suppressed luminal narrowing progression from local drug effects on the de novo coronary lesions.

Optical coherence tomography and histopathology assessment after implantation of first- and second-generation drug-eluting stents in a porcine coronary model

BACKGROUND

This study directly compared optical coherence tomography (OCT) and histopathology for the assessment of vascular response to first- and second-generation drug-eluting stents. METHODS AND RESULTS: Sirolimus-, everolimus-, and biolimus-eluting stents (SES, EES, and BES, respectively) were randomly implanted into the coronary arteries of 12 porcine. OCT was conducted after implantation: at 1, 3, and 6 months; histopathology was assessed at 3 and 6 months. At 1-month OCT, EES had the highest neointimal area (NA) and lowest neointimal unevenness score (NUS). At 6 months, NA and NUS were equivalent among the stent types. ∆NA from 1 to 6 months was lowest for EES, and ∆NA correlated with the histopathological inflammation score at 6 months, which was highest for SES (P<0.001). The mean signal intensity (MSI) and the attenuation were different for the stent types at 3 months, and were associated with inflammation score. Moderate diagnostic efficiency for measuring MSI was found, with an optimal cut-off of 6.88 predicting a high (≥grade 3) inflammation score.

CONCLUSIONS

EES had the greatest uniformity and the least neointimal proliferation and were associated with less persistent inflammation. OCT provides accurate morphometric data; furthermore, quantitative measurement of the optical properties may help assess histological inflammation, which was more predominantly associated with SES than with EES and BES.

Polymeric stent materials dysregulate macrophage and endothelial cell functions: implications for coronary artery stent

BACKGROUND

Biodegradable polymers have been applied as bulk or coating materials for coronary artery stents. The degradation of polymers, however, could induce endothelial dysfunction and aggravate neointimal formation. Here we use polymeric microparticles to simulate and demonstrate the effects of degraded stent materials on phagocytic activity, cell death and dysfunction of macrophages and endothelial cells.

METHODS

Microparticles made of low molecular weight polyesters were incubated with human macrophages and coronary artery endothelial cells (ECs). Microparticle-induced phagocytosis, cytotoxicity, apoptosis, cytokine release and surface marker expression were determined by immunostaining or ELISA. Elastase expression was analyzed by ELISA and the elastase-mediated polymer degradation was assessed by mass spectrometry.

RESULTS

We demonstrated that poly(D,L-lactic acid) (PLLA) and polycaprolactone (PCL) microparticles induced cytotoxicity in macrophages and ECs, partially through cell apoptosis. The particle treatment alleviated EC phagocytosis, as opposed to macrophages, but enhanced the expression of vascular cell adhesion molecule (VCAM)-1 along with decreased nitric oxide production, indicating that ECs were activated and lost their capacity to maintain homeostasis. The activation of both cell types induced the release of elastase or elastase-like protease, which further accelerated polymer degradation.

CONCLUSIONS

This study revealed that low molecule weight PLLA and PCL microparticles increased cytotoxicity and dysregulated endothelial cell function, which in turn enhanced elastase release and polymer degradation. These indicate that polymer or polymer-coated stents impose a risk of endothelial dysfunction after deployment which can potentially lead to delayed endothelialization, neointimal hyperplasia and late thrombosis.

Modeling and imaging cardiac sympathetic neurodegeneration in Parkinson's disease

Parkinson's disease (PD) is currently recognized as a multisystem disorder affecting several components of the central and peripheral nervous system. This new understanding of PD helps explain the complexity of the patients' symptoms while challenges researchers to identify new diagnostic and therapeutic strategies. Cardiac neurodegeneration and dysautonomia affect PD patients and are associated with orthostatic hypotension, fatigue, and abnormal control of electrical heart activity. They can seriously impact daily life of PD patients, as these symptoms do not respond to classical anti-parkinsonian medications and can be worsened by them. New diagnostic tools and therapies aiming to prevent cardiac neurodegeneration and dysautonomia are needed. In this manuscript we critically review the relationship between the cardiovascular and nervous system in normal and PD conditions, current animal models of cardiac dysautonomia and the application of molecular imaging methods to visualize cardiac neurodegeneration. Our goal is to highlight current progress in the development of tools to understand cardiac neurodegeneration and dysautonomia and monitor the effects of novel therapies aiming for global neuroprotection.

Propofol protects against high glucose-induced endothelial adhesion molecules expression in human umbilical vein endothelial cells

BACKGROUND

Hyperglycemia could induce oxidative stress, activate transcription factor nuclear factor kappa B (NF-κB), up-regulate expression of endothelial adhesion molecules, and lead to endothelial injury. Studies have indicated that propofol could attenuate oxidative stress and suppress NF-κB activation in some situations. In the present study, we examined whether and how propofol improved high glucose-induced up-regulation of endothelial adhesion molecules in human umbilical vein endothelial cells (HUVECs).

METHODS

Protein expression of endothelial adhesion molecules, NF-κB, inhibitory subunit of NF-κBα (IκBα), protein kinase Cβ2 (PKCβ2), and phosphorylation of PKCβ2 (Ser(660)) were measured by Western blot. NF-κB activity was measured by electrophoretic mobility shift assay. PKC activity was measured with SignaTECT PKC assay system. Superoxide anion (O(2)(.-)) accumulation was measured with the reduction of ferricytochrome c assay. Human peripheral mononuclear cells were prepared with Histopaque-1077 solution.

RESULTS

High glucose induced the expression of endothelial selectin (E-selectin), intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1), and increased mononuclear-endothelial adhesion. High glucose induced O(2)(.-) accumulation, PKCβ2 phosphorylation and PKC activation. Further, high glucose decreased IκBα expression in cytoplasm, increased the translocation of NF-κB from cytoplasm to nuclear, and induced NF-κB activation. Importantly, we found these high glucose-mediated effects were attenuated by propofol pretreatment. Moreover, CGP53353, a selective PKCβ2 inhibitor, decreased high glucose-induced NF-κB activation, adhesion molecules expression, and mononuclear-endothelial adhesion.

CONCLUSION

Propofol, via decreasing O(2)(.-) accumulation, down-regulating PKCβ2 Ser(660) phosphorylation and PKC as well as NF-κB activity, attenuated high glucose-induced endothelial adhesion molecules expression and mononuclear-endothelial adhesion.

Animal models of diabetes mellitus for islet transplantation

Due to current improvements in techniques for islet isolation and transplantation and protocols for immunosuppressants, islet transplantation has become an effective treatment for severe diabetes patients. Many diabetic animal models have contributed to such improvements. In this paper, we focus on 3 types of models with different mechanisms for inducing diabetes mellitus (DM): models induced by drugs including streptozotocin (STZ), pancreatomized models, and spontaneous models due to autoimmunity. STZ-induced diabetes is one of the most commonly used experimental diabetic models and is employed using many specimens including rodents, pigs or monkeys. The management of STZ models is well established for islet studies. Pancreatomized models reveal different aspects compared to STZ-induced models in terms of loss of function in the increase and decrease of blood glucose and therefore are useful for evaluating the condition in total pancreatomized patients. Spontaneous models are useful for preclinical studies including the assessment of immunosuppressants because such models involve the same mechanisms as type 1 DM in the clinical setting. In conclusion, islet researchers should select suitable diabetic animal models according to the aim of the study.

Detecting DNA synthesis of neointimal formation after catheter balloon injury in GK and in Wistar rats: using 5-ethynyl-2'-deoxyuridine

Background

Neointimal formation plays an important role in the pathogenesis of coronary restenosis after percutaneous coronary intervention (PCI), especially in patients with diabetes mellitus. Recently, some studies have shown that 5-ethynyl-2'-deoxyuridine (EdU) incorporation can serve as a novel alternative to the 5-bromo-2'-deoxyuridine (BrdU) antibody detection method for detection of DNA synthesis in regenerating avian cochlea, chick embryo and the adult nervous system. However, few studies have been performed to assess the suitability of EdU for detecting DNA synthesis in vascular neointima.

Methods

The carotid artery balloon injury model was established in Goto-Kakizaki (GK) and Wistar rats. A Cell-Light^TM EdU Kit was used to detect EdU-labeled cell nuclei of common carotid arteries at day 7 after catheter balloon injury. Different methods of injecting EdU were tested. The protein levels of proliferating cell nuclear antigen (PCNA) and p-Akt (Ser473), as well as the mRNA levels of PCNA were evaluated by Western blotting and quantitative real-time PCR (qRT-PCR), respectively. Immunohistochemical staining was also employed to visualize PCNA-positive cells.

Results

At day 7 after catheter balloon injury, far more EdU-positive and PCNA-positive cells were observed in GK rats. When comparing groups that received different EdU doses, it was found that the percentage of EdU-positive cells at a dose of 100 mg/kg body weight was than at doses of 25 mg/kg and 50 mg/kg. The number of positive cells was significantly higher in the repeated injection group compared to the single injection group. Further, after balloon injury DNA synthesis in GK rats was more notable than in Wistar rats. Neointimal formation in GK rats was more obvious than in Wistar rats. The protein levels of PCNA and p-Akt (Ser473) and the mRNA levels of PCNA were increased in injured rats as compared to uninjured rats, and were significantly higher in GK rats than in Wistar rats.

Conclusion

By intraperitoneal injections of EdU at a dose of 100 mg/kg three times, EdU incorporation can detect carotid arterial DNA synthesis caused by neointimal formation in GK rats and Wistar rats at day 7 after balloon injury by the EdU click reaction quickly and effectively. Moreover, more obvious DNA synthesis in the vascular neointima could be observed in GK rats than in Wistar rats.