Drug-eluting coronary stents: insights from preclinical and pathology studies

Drug-coated balloon angioplasty versus drug-eluting stent implantation in ACS patients with different angiographic patterns of in-stent restenosis

BACKGROUND

Drug-coated balloon (DCB) angioplasty and drug-eluting stents (DES) are two widely used treatments for in-stent restenosis (ISR). Focal and non-focal types of ISR affect the clinical outcomes. The present study aims to compare DES reimplantation versus DCB angioplasty in acute coronary syndrome (ACS) patients with focal ISR and non-focal ISR lesions.

METHODS

Patients with ISR lesions underwent percutaneous coronary intervention (PCI) were retrospectively evaluated and divided into DES group and DCB group. The primary endpoint was the incidence of target lesion failure (TLF) at 24 months follow up. Propensity score matching (PSM) was conducted to balance the baseline characteristics.

RESULTS

For focal ISR, TLF was comparable in the DES and DCB groups at 24 months of follow-up (Before PSM, hazard ratio [HR]: 0.70; 95% confidence interval [CI]: 0.39-1.27; p = 0.244; After PSM, HR: 0.83; 95% CI: 0.40-1.73; p = 0.625). For non-focal ISR, TLF was significantly decreased in DES compared with DCB group (Before PSM, HR: 0.43; 95% CI: 0.29-0.63; p < 0.001; After PSM, HR: 0.33; 95% CI: 0.19-0.59; p < 0.001), which was mainly attributed to the lower incidence of clinically indicated target lesion revascularization (CD-TLR) (Before PSM, HR: 0.39; 95% CI: 0.26-0.59; p < 0.001; After PSM, HR: 0.28; 95% CI: 0.15-0.54; p < 0.001).

CONCLUSIONS

The clinical outcomes for DES and DCB treatment are similar in focal type of ISR lesions. For non-focal ISR, the treatment of DES showed a significant decrease in TLF which was mainly attributed to a lower incidence of CD-TLR.

Identification of endothelial protein C receptor as a novel druggable agonistic target for reendothelialization promotion and thrombosis prevention of eluting stent

The commercially available drug-eluting stent with limus (rapamycin, everolimus, etc.) or paclitaxel inhibits smooth muscle cell (SMC), reducing the in-stent restenosis, whereas damages endothelial cell (EC) and delays stent reendothelialization, increasing the risk of stent thrombosis (ST) and sudden cardiac death. Here we present a new strategy for promoting stent reendothelialization and preventing ST by exploring the application of precise molecular targets with EC specificity. Proteomics was used to investigate the molecular mechanism of EC injury caused by rapamycin. Endothelial protein C receptor (EPCR) was screened out as a crucial EC-specific effector. Limus and paclitaxel repressed the EPCR expression, while overexpression of EPCR protected EC from coating (eluting) drug-induced injury. Furthermore, the ligand activated protein C (APC), polypeptide TR47, and compound parmodulin 2, which activated the target EPCR, promoted EC functions and inhibited platelet or neutrophil adhesion, and enhanced rapamycin stent reendothelialization in the simulated stent environment and in vitro. In vivo, the APC/rapamycin-coating promoted reendothelialization rapidly and prevented ST more effectively than rapamycin-coating alone, in both traditional metal stents and biodegradable stents. Additionally, overexpression or activation of the target EPCR did not affect the cellular behavior of SMC or the inhibitory effect of rapamycin on SMC. In conclusion, EPCR is a promising therapeutical agonistic target for pro-reendothelialization and anti-thrombosis of eluting stent. Activation of EPCR protects against coating drugs-induced EC injury, inflammatory cell, or platelet adhesion onto the stent. The novel application formula for APC/rapamycin-combined eluting promotes stent reendothelialization and prevents ST.

Pathological evaluation of predictors for delayed endothelial coverage after currently available drug-eluting stent implantation in coronary arteries: Impact of lesions with acute and chronic coronary syndromes

BACKGROUND

The optimal duration of dual antiplatelet therapy after currently available drug-eluting stent (DES) implantation to prevent stent thrombosis (ST) remains controversial. Delayed healing is frequently identified as a leading cause of ST in the early phase. However, a thorough pathological investigation into strut coverage after currently available DES implantation is lacking-a gap addressed in the current study.

METHODS

From our autopsy registry of 199 stented lesions, 4,713 struts from 66 currently available DES-stented lesions with an implant duration ≤370 days were histologically evaluated. Endothelial coverage was defined as the presence of luminal endothelial cells overlying struts and an underlying smooth muscle cell layer. The stented lesions were classified into acute coronary syndrome (ACS) (n = 40) and chronic coronary syndrome (CCS) (n = 26) groups and were compared. Endothelial coverage predictors were identified through logistic analysis.

RESULTS

Although ACS and CCS lesions presented comparable clinical characteristics, including age, sex, and cause of death, the latter exhibited a significantly higher prevalence of chronic kidney disease and hemodialysis than the former (33.3% vs. 65.2%; P = .02, 7.7% vs. 30.4%; P = .02). The poststent implant median duration was significantly shorter in ACS lesions than in CCS lesions (13 [IQR 5-26 days] vs. 40 [IQR 16-233 days]; P < .01). The endothelial coverage percentage was 3.5% at 30 days and 27.7% at 90 days after currently available DES implantation. Multivariable logistic regression analysis implicated implant duration of ≤90 days (odds ratio [OR], 0.009; 95% confidence interval [CI], 0.006-0.012; P < .01), superficial calcification (OR, 0.11; 95% CI, 0.07-0.17; P < .01), ACS culprit site (OR, 0.29; 95% CI, 0.09-0.94; P = .039), and circumferentially durable polymer-coated DES (OR, 0.32; 95% CI, 0.24-0.41; P < .01) as delayed endothelial coverage predictors.

CONCLUSIONS

Endothelial coverage was limited at 90 days after currently available DES implantation, and the ACS culprit site and circumferentially durable polymer-coated DES were identified as independent predictors of delayed endothelial coverage. Our findings suggest the importance of underlying plaque morphology and stent technology for vessel healing after such implantation.

Unravelling the progress and potential of drug-eluting stents and drug-coated balloons in cardiological insurgencies

AIM

Coronary artery disease (CAD) is the leading cause of mortality. Though percutaneous transluminal angioplasty followed by stenting is still the default treatment of choice for revascularization of obstructive CAD, the high rate of restenosis compromises the outcomes of endovascular procedures. To overcome restenosis, drug-eluting stents (DES) and drug-coated balloons (DCB) are designed that release antiproliferative drugs like sirolimus, paclitaxel, everolimus, etc., over time to inhibit cell growth and proliferation. Our review aims to summarize the challenges and progress of DES/DCBs in clinical settings.

MATERIAL AND METHODS

The comprehensive review, search and selection encompasses in relevant articles through Google Scholar, Springer online, Cochrane library and PubMed that includes research articles, reviews, letters and communications, various viewpoints, meta-analyses, randomized trials and quasi-randomized trials. Several preclinical and clinical data have been included from National Institutes of Health and clinicaltrials.gov websites.

KEY FINDINGS

Challenges like delayed endothelialization, stent thrombosis (ST), and inflammation was prominent in first-generation DES. Second-generation DES with improved designs and drug coatings enhanced biocompatibility with fewer complications. Gradual absorption of bioresorbable DES over time mitigated long-term issues associated with permanent implants. Polymer-free DES addressed the inflammation concerns but still, they leave behind metallic stents in the vasculature. As an alternative therapeutic strategy, DCB were developed to minimize inflammation in the vessel. Although both DES and DCBs have shown considerable progress, challenges persist.

SIGNIFICANCE

This review illustrates the advancements in the designs, preparation technologies, biodegradable materials, and drugs used as well as challenges associated with DES and DCBs in clinical settings.

Clinical outcomes with biodegradable versus durable polymer drug-eluting stents in patients with ST-elevation myocardial infarction

BACKGROUND

Coronary drug-eluting stents (DES) built with either durable (DP) or biodegradable (BP) polymeric coatings have been largely tested and are extensively available for routine use. However, their comparative performance remains an open question, particularly in more complex subsets of patients.

AIMS

We evaluated the outcomes of patients with ST-elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (pPCI) using DP-DES versus BP-DES in a large multicenter real-world registry.

METHODS

The population comprised patients with STEMI treated with pPCI within 12 h of symptoms onset. Those treated with more than one DES who received different polymer types were excluded. The final cohort for analysis was selected after propensity score matching (PSM), computed to generate similar groups of DP DES versus BP DES. Primary endpoint was the incidence of major adverse cardiac events (MACE), defined as the composite of total death, myocardial infarction and target lesion revascularization at 2 years.

RESULTS

From January 2017 to April 2022, a total of 1527 STEMI patients underwent pPCI with a single DES type (587 DP-DES; 940 BP-DES). After PSM, 836 patients (418 patients in the DP-DES and 418 patients in the BP-DES groups), comprised the final study population. Both study groups had a similar baseline profile. Patients treated with BP-DES group had similar rates of MACE (15.3 % vs. 19.4 %, HR 0.69, 95 % CI 0.50-0.94, p = 0.022). Rates of target lesion revascularization was lower in BP DES group (0.7 % vs. 3.8 %, HR 0.17, 95 % CI 0.05-0.51, p = 0.006).

CONCLUSION

In a cohort of STEMI patients submitted to pPCI, BP and DP DES had similar rates of the primary outcome. Patients treated with BP DES, however, had a decreased incidence of TLR at after 2-year follow-up.

Research Progress on the Pathogenesis and Treatment of Neoatherosclerosis

Neoatherosclerosis (NA) within stents has become an important clinical problem after coronary artery stent implantation. In-stent restenosis and in-stent thrombosis are the two major complications following coronary stent placement and seriously affect patient prognosis. As the common pathological basis of these two complications, NA plaques, unlike native atherosclerotic plaques, often grow around residual oxidized lipids and stent struts. The main components are foam cells formed by vascular smooth muscle cells (VSMCs) engulfing oxidized lipids at lipid residue sites. Current research mainly focuses on optical coherence tomography (OCT) and intravascular ultrasound (IVUS), but the specific pathogenesis of NA is still unclear. A thorough understanding of the pathogenesis and pathological features of NA provides a theoretical basis for clinical treatment. This article reviews the previous research of our research group and the current situation of domestic and foreign research.

Degradation of a novel magnesium alloy-based bioresorbable coronary scaffold in a swine coronary artery model

The objective of the study is to investigate the safety, feasibility, and degradation profile of a novel Mg alloy-based bioresorbable coronary scaffold (JFK-PRODUCT BRS) with thin struts (110 μm). Polymer- or Mg alloy-based BRSs have not replaced nondegradable metal stents because of the higher prevalence of scaffold thrombosis and restenosis in clinical practice; these poor clinical outcomes were due to inadequate scaffold designs, including thick struts (more than 150 μm) and their inappropriate degradation processes. Fourteen healthy pigs received 17 JFK-PRODUCT BRSs in the coronary arteries and were sacrificed at 1, 6, 12, 18, and 26 months after implantation. Angiography, optical coherence tomography, microfocus X-ray computed tomography (µCT), scanning electron microscopy with energy-dispersive X-ray spectrometry (SEM-EDX), and histopathological evaluation were performed. The JFK-PRODUCT had a median percent late recoil of 11.28% at 1 month. The µCT observation confirmed that scaffold discontinuity reached 64.8% at 12 months with increased scaffold inner area thereafter, suggesting artery positive remodeling. The inflammation was mild, peaked at 18 months, and decreased thereafter. The SEM-EDX analysis demonstrated gradual degradation of the scaffold with formation of inorganic deposits, presumed to be calcium phosphates. It also revealed the disappearance of calcium phosphates at 26 months, achieving almost complete replacement of the scaffold by biocomponents. The current study demonstrated the safety and feasibility of JFK-PRODUCT with a lower acute recoil rate despite its thin struts. The scaffolds were almost completely disappeared at 26 months after implantation.

Bioelectronic Neural Interfaces: Improving Neuromodulation Through Organic Conductive Coatings

Integration of bioelectronic devices in clinical practice is expanding rapidly, focusing on conditions ranging from sensory to neurological and mental health disorders. While platinum (Pt) electrodes in neuromodulation devices such as cochlear implants and deep brain stimulators have shown promising results, challenges still affect their long-term performance. Key among these are electrode and device longevity in vivo, and formation of encapsulating fibrous tissue. To overcome these challenges, organic conductors with unique chemical and physical properties are being explored. They hold great promise as coatings for neural interfaces, offering more rapid regulatory pathways and clinical implementation than standalone bioelectronics. This study provides a comprehensive review of the potential benefits of organic coatings in neuromodulation electrodes and the challenges that limit their effective integration into existing devices. It discusses issues related to metallic electrode use and introduces physical, electrical, and biological properties of organic coatings applied in neuromodulation. Furthermore, previously reported challenges related to organic coating stability, durability, manufacturing, and biocompatibility are thoroughly reviewed and proposed coating adhesion mechanisms are summarized. Understanding organic coating properties, modifications, and current challenges of organic coatings in clinical and industrial settings is expected to provide valuable insights for their future development and integration into organic bioelectronics.

Durable-polymer versus biodegradable-polymer drug-eluting stents in acute coronary syndromes: three-year outcomes of the HOST REDUCE POLYTECH RCT Trial

BACKGROUND

Long-term follow-up is essential to evaluate the impact of polymer degradation in drug-eluting stents (DES).

AIMS

We aimed to compare durable-polymer DES (DP-DES) and biodegradable-polymer DES (BP-DES) during a 3-year follow-up to evaluate the entire period of polymer resolution (before, during, and after degradation).

METHODS

The HOST REDUCE POLYTECH RCT Trial was a randomised clinical trial enrolling patients with acute coronary syndrome (ACS) and comparing the efficacy and safety of DP-DES and BP-DES. The primary outcome was a patient-oriented composite outcome (POCO), and the key secondary outcome was a device-oriented composite outcome (DOCO).

RESULTS

A total of 3,413 ACS patients were randomised to either the DP-DES (1,713 patients) or BP-DES (1,700 patients) group. During the 3-year follow-up, the risk of the POCO was similar between the DP-DES and BP-DES groups (14.8% vs 15.4%, hazard ratio [HR] 0.96, 95% confidence interval [CI]: 0.80-1.14; p=0.613). However, the risk of the DOCO was lower in the DP-DES group (6.0% vs 8.0%, HR 0.73, 95% CI: 0.57-0.95; p=0.020). In a landmark analysis, the lower risk of the DOCO for the DP-DES group was evident during the transition from the early to the late period after percutaneous coronary intervention (PCI) (from 8 to 16 months post-PCI; 1.8% vs 3.3%, HR 0.54, 95% CI: 0.34-0.84; p=0.007), which was mainly driven by a risk reduction of target lesion revascularisation.

CONCLUSIONS

In ACS patients, DP-DES showed similar results to BP-DES regarding the POCO up to 3 years. For the DOCO, DP-DES were superior to BP-DES; this was due to the higher event rate during the period of polymer degradation.

Optimizing the Biocompatibility of PLLA Stent Materials: Strategy with Biomimetic Coating

Background

Poly-L-lactic acid (PLLA) stents have broad application prospects in the treatment of cardiovascular diseases due to their excellent mechanical properties and biodegradability. However, foreign body reactions caused by stent implantation remain a bottleneck that limits the clinical application of PLLA stents. To solve this problem, the biocompatibility of PLLA stents must be urgently improved. Albumin, the most abundant inert protein in the blood, possesses the ability to modify the surface of biomaterials, mitigating foreign body reactions-a phenomenon described as the "stealth effect". In recent years, a strategy based on albumin camouflage has become a focal point in nanomedicine delivery and tissue engineering research. Therefore, albumin surface modification is anticipated to enhance the surface biological characteristics required for vascular stents. However, the therapeutic applicability of this modification has not been fully explored.

Methods

Herein, a bionic albumin (PDA-BSA) coating was constructed on the surface of PLLA by a mussel-inspired surface modification technique using polydopamine (PDA) to enhance the immobilization of bovine serum albumin (BSA).

Results

Surface characterization revealed that the PDA-BSA coating was successfully constructed on the surface of PLLA materials, significantly improving their hydrophilicity. Furthermore, in vivo and in vitro studies demonstrated that this PDA-BSA coating enhanced the anticoagulant properties and pro-endothelialization effects of the PLLA material surface while inhibiting the inflammatory response and neointimal hyperplasia at the implantation site.

Conclusion

These findings suggest that the PDA-BSA coating provides a multifunctional biointerface for PLLA stent materials, markedly improving their biocompatibility. Further research into the diverse applications of this coating in vascular implants is warranted.

Efficacy and Safety of Sirolimus-Eluting Stent With Biodegradable Polymer Ultimaster™ in Unselected Korean Population: A Multicenter, Prospective, Observational Study From Korean Multicenter Ultimaster Registry

BACKGROUND AND OBJECTIVES

Ultimaster™, a third-generation sirolimus-eluting stent using biodegradable polymer, has been introduced to overcome long term adverse vascular events, such as restenosis or stent thrombosis. In the present study, we aimed to evaluate the 12-month clinical outcomes of Ultimaster™ stents in Korean patients with coronary artery disease.

METHODS

This study is a multicenter, prospective, observational registry across 12 hospitals. To reflect real-world clinical evidence, non-selective subtypes of patients and lesions were included in this study. The study end point was target lesion failure (TLF) (the composite of cardiac death, target vessel myocardial infarction [MI], and target lesion revascularization [TLR]) at 12-month clinical follow up.

RESULTS

A total of 576 patients were enrolled between November 2016 and May 2021. Most of the patients were male (76.5%), with a mean age of 66.0±11.2 years. Among the included patients, 40.1% had diabetes mellitus (DM) and 67.9% had acute coronary syndrome (ACS). At 12 months, the incidence of TLF was 4.1%. The incidence of cardiac death was 1.5%, MI was 1.0%, TLR was 2.7%, and stent thrombosis was 0.6%. In subgroup analysis based on the presence of ACS, DM, hypertension, dyslipidemia, or bifurcation, there were no major differences in the incidence of the primary endpoint.

CONCLUSIONS

The present registry shows that Ultimaster™ stent is safe and effective for routine real-world clinical practice in non-selective Korean patients, having a low rate of adverse events at least up to 12 months.

3D printing technology and its revolutionary role in stent implementation in cardiovascular disease

Cardiovascular disease (CVD), exemplified by coronary artery disease (CAD), is a global health concern, escalating in prevalence and burden. The etiology of CAD is intricate, involving different risk factors. CVD remains a significant cause of mortality, driving the need for innovative interventions like percutaneous coronary intervention and vascular stents. These stents aim to minimize restenosis, thrombosis, and neointimal hyperplasia while providing mechanical support. Notably, the challenges of achieving ideal stent characteristics persist. An emerging avenue to address this involves enhancing the mechanical performance of polymeric bioresorbable stents using additive manufacturing techniques And Three-dimensional (3D) printing, encompassing various manufacturing technologies, has transcended its initial concept to become a tangible reality in the medical field. The technology's evolution presents a significant opportunity for pharmaceutical and medical industries, enabling the creation of targeted drugs and swift production of medical implants. It revolutionizes medical procedures, transforming the strategies of doctors and surgeons. Patient-specific 3D-printed anatomical models are now pivotal in precision medicine and personalized treatment approaches. Despite its ongoing development, additive manufacturing in healthcare is already integrated into various medical applications, offering substantial benefits to a sector under pressure for performance and cost reduction. In this review primarily emphasizes stent technology, different types of stents, highlighting its application with some potential complications. Here we also address their benefits, potential issues, effectiveness, indications, and contraindications. In future it can potentially reduce complications and help in improving patients' outcomes. 3DP technology offers the promise to customize solutions for complex CVD conditions and help or fostering a new era of precision medicine in cardiology.

Clinical Value of the Quantitative Flow Ratio to Predict Long-term Target Vessel Failure in Patients with In-stent Restenosis after Drug-coated Balloon Angioplasty

OBJECTIVE

The study sought to investigate the clinical predictive value of quantitative flow ratio (QFR) for the long-term target vessel failure (TVF) outcome in patients with in-stent restenosis (ISR) by using drug-coated balloon (DCB) treatment after a long-term follow-up.

METHODS

This was a retrospective study. A total of 186 patients who underwent DCB angioplasty for ISR in two hospitals from March 2014 to September 2019 were enrolled. The QFR of the entire target vessel was measured offline. The primary endpoint was TVF, including target vessel-cardiac death (TV-CD), target vessel-myocardial infarction (TV-MI), and clinically driven-target vessel revascularization (CD-TVR).

RESULTS

The follow-up time was 3.09±1.53 years, and 50 patients had TVF. The QFR immediately after percutaneous coronary intervention (PCI) was significantly lower in the TVF group than in the no-TVF group. Multivariable Cox regression analysis indicated that the QFR immediately after PCI was an excellent predictor for TVF after the long-term follow-up [hazard ratio (HR): 5.15×10-5 (6.13×10-8-0.043); P<0.01]. Receiver-operating characteristic (ROC) curve analysis demonstrated that the optimal cut-off value of the QFR immediately after PCI for predicting the long-term TVF was 0.925 (area under the curve: 0.886, 95% confidence interval: 0.834-0.938; sensitivity: 83.40%, specificity: 88.00; P<0.01). In addition, QFR≤0.925 post-PCI was strongly correlated with the TVF, including TV-MI and CD-TVR (P<0.01).

CONCLUSION

The QFR immediately after PCI showed a high predictive value of TVF after a long-term follow-up in ISR patients who underwent DCB angioplasty. A lower QFR immediately after PCI was associated with a worse TVF outcome.

Two-Year Outcomes for Patients with Non-ST-Elevation Acute Coronary Syndrome Treated with Magmaris and Absorb Bioresorbable Scaffolds in Large-Vessel Lesions

BACKGROUND

The acute coronary syndrome (ACS) continues to be a fundamental indication for revascularization by percutaneous coronary intervention (PCI). Drug-eluting stent (DES) implantation remains a part of contemporary practice but permanent caging of the vascular structure with the metallic stent structure may increase the rate of device-related adverse clinical events. As an alternative to classic metallic DESs, the bioresorbable scaffolds (BRSs) have emerged as a temporary vascular support technology. We evaluated the mid-term outcomes of two generations of bioresorbable scaffolds-Absorb (Abbott-Vascular, Chicago, IL, USA) and Magmaris (Biotronik, Germany)-in patients with non-ST-elevation ACS.

METHODS

The study cohort consisted of 193 subjects after Magmaris implantation and 160 patients following Absorb implantation in large-vessel lesions.

RESULTS

At 2 years, a significantly lower rate of a primary outcome (cardiac death, myocardial infarction, stent thrombosis) was observed with Magmaris (5.2% vs. 15%; p = 0.002). In addition, we observed a significantly lower rate of MI in the target vessel (2.6% vs. 9.4%; p = 0.009) and a lower rate of scaffold thrombosis (0% vs. 3.7%; p = 0.008). The TLF rate between the two groups was not significantly different.

CONCLUSION

Magmaris demonstrated a good safety profile and more favorable clinical outcomes when compared to Absorb in patients with non-ST-elevation ACS.

A unique mechanism of restenosis after drug-coated balloon in peripheral artery: Insight from optical frequency domain imaging

Drug-coated balloons (DCBs) have been widely used in endovascular therapy for femoropopliteal arteries with atherosclerotic lesions. Vascular response after DCBs remains unclear. This mini-review proposes a possible mechanism of restenosis after the DCB strategy. Balloon dilatation including DCBs expands the vascular lumen by producing dissections, which is composed of the original vascular lumen and the cavity surrounded by dissected flaps. The cavity surrounded by dissected flaps is eventually replaced with the thrombus in the healing process after balloon dilatation. However, the thrombus may propagate to the expanded vascular lumen through the entry point of the dissection. Subsequently, the thrombus both in the cavity and the expanded lumen would be organized over time. The vascular lumen in the chronic-phase after DCBs may be influenced by the propagated thrombus from the cavity surrounded by dissected flaps.

Current Management of In-Stent Restenosis

In-stent restenosis (ISR) remains the primary cause of target lesion failure following percutaneous coronary intervention (PCI), resulting in 10-year incidences of target lesion revascularization at a rate of approximately 20%. The treatment of ISR is challenging due to its inherent propensity for recurrence and varying susceptibility to available strategies, influenced by a complex interplay between clinical and lesion-specific conditions. Given the multiple mechanisms contributing to the development of ISR, proper identification of the underlying substrate, especially by using intravascular imaging, becomes pivotal as it can indicate distinct therapeutic requirements. Among standalone treatments, drug-coated balloon (DCB) angioplasty and drug-eluting stent (DES) implantation have been the most effective. The main advantage of a DCB-based approach is the avoidance of an additional metallic layer, which may otherwise enhance neointimal hyperplasia, provide the substratum for developing neoatherosclerosis, and expose the patient to a persistently higher risk of coronary ischemic events. On the other hand, target vessel scaffolding by DES implantation confers relevant mechanical advantages over DCB angioplasty, generally resulting in larger luminal gain, while drug elution from the stent surface ensures the inhibition of neointimal hyperplasia. Nevertheless, repeat stenting with DES also implies an additional permanent metallic layer that may reiterate and promote the mechanisms leading to ISR. Against this background, the selection of either DCB or DES on a patient- and lesion-specific basis as well as the implementation of adjuvant treatments, including cutting/scoring balloons, intravascular lithotripsy, and rotational atherectomy, hold the potential to improve the effectiveness of ISR treatment over time. In this review, we comprehensively assessed the available evidence from randomized trials to define contemporary interventional treatment of ISR and provide insights for future directions.

Robust, Sprayable, and Multifunctional Hydrogel Coating through a Polycation Reinforced (PCR) Surface Bridging Strategy

The sprayable hydrogel coatings that can establish robust adhesion onto diverse materials and devices hold enormous potential; however, a significant challenge persists due to monomer hydration, which impedes even coverage during spraying and induces inadequate adhesion post-gelation. Herein, a polycation-reinforced (PCR) surface bridging strategy is presented to achieve tough and sprayable hydrogel coatings onto diverse materials. The polycations offer superior wettability and instant electrostatic interactions with plasma-treated substrates, facilitating an effective spraying application. This PCR-based hydrogel coatings demonstrate tough adhesion performance to inert PTFE and silicone, including remarkable shear strength (161 ± 49 kPa for PTFE), interfacial toughness (198 ± 27 J m-2 for PTFE), and notable tolerance to cyclic tension (10 000 cycles, 200% strain, silicone). Meanwhile, this method can be applied to various hydrogel formulations, offering diverse functionalities, including underwater adhesion, lubrication, and drug delivery. Furthermore, the PCR concept enables the conformal construction of durable hydrogel coatings onto sophisticated medical devices like cardiovascular stents. Given its simplicity and adaptability, this approach paves an avenue for incorporating hydrogels onto solid surfaces and potentially promotes untapped applications.

Efficacy and safety of durable versus biodegradable polymer drug-eluting stents in patients with acute myocardial infarction complicated by cardiogenic shock

The clinical impact of different polymer technologies in newer-generation drug-eluting stents (DESs) for patients with acute myocardial infarction (AMI) complicated by cardiogenic shock (CS) remains poorly understood. We investigated the efficacy and safety of durable polymer DESs (DP-DESs) compared with biodegradable polymer DESs (BP-DESs). A total of 620 patients who underwent percutaneous coronary intervention with newer-generation DESs for AMI complicated by CS was divided into two groups based on polymer technology: the DP-DES group (n = 374) and the BP-DES group (n = 246). The primary outcome was target vessel failure (TVF) during a 12-month follow-up, defined as a composite of cardiac death, myocardial infarction, or target vessel revascularization. Both the DP-DES and BP-DES groups exhibited low stent thrombosis rates (1.3% vs. 1.6%, p = 0.660). The risk of TVF did not significantly differ between the two groups (34.2% vs. 28.5%, hazard ratio [HR] 0.94, 95% confidence interval [CI] 0.69-1.29, p = 0.721). This finding remained consistent after adjustment with inverse probability of treatment weighting (28.1% vs. 25.1%, HR 0.98, 95% CI 0.77-1.27, p = 0.899). In AMI patients complicated by CS, the risk of a composite of cardiac death, myocardial infarction, or target vessel revascularization was not significantly different between those treated with DP-DESs and those treated with BP-DESs.Trial registration: RESCUE registry, https://clinicaltrials.gov/ct2/show/NCT02985008 , NCT02985008.

P2Y12 Inhibitor Monotherapy vs Dual Antiplatelet Therapy After Deployment of a Drug-Eluting Stent: The SHARE Randomized Clinical Trial

Importance

P2Y12 inhibitor monotherapy after dual antiplatelet therapy (DAPT; a P2Y12 inhibitor plus aspirin) for a brief duration has recently emerged as an attractive alternative for patients undergoing percutaneous coronary intervention (PCI) with a drug-eluting stent.

Objective

To investigate whether P2Y12 inhibitor monotherapy after 3 months of DAPT was noninferior to 12 months of DAPT following PCI with a drug-eluting stent.

Design, Setting, and Participants

The Short-Term Dual Antiplatelet Therapy After Deployment of Bioabsorbable Polymer Everolimus-Eluting Stent (SHARE) open-label, noninferiority randomized clinical trial was conducted from December 15, 2017, through December 14, 2020. Final 1-year clinical follow-up was completed in January 2022. This study was a multicenter trial that was conducted at 20 hospitals in South Korea. Patients who underwent successful PCI with bioabsorbable polymer everolimus-eluting stents were enrolled.

Interventions

Patients were randomly assigned to receive P2Y12 inhibitor monotherapy after 3 months of DAPT (n = 694) or 12 months of DAPT (n = 693).

Main Outcomes and Measures

The primary outcome was a net adverse clinical event, a composite of major bleeding (based on Bleeding Academic Research Consortium type 3 or type 5 bleeding) and major adverse cardiac and cerebrovascular events (cardiac death, myocardial infarction, stent thrombosis, stroke, or ischemia-driven target lesion revascularization) between 3 and 12 months after the index PCI. The major secondary outcomes were major adverse cardiac and cerebrovascular events and major bleeding. The noninferiority margin was 3.0%.

Results

Of the total 1452 eligible patients, 65 patients were excluded before the 3-month follow-up, and 1387 patients (mean [SD] age, 63.0 [10.7] years; 1055 men [76.1%]) were assigned to P2Y12 inhibitor monotherapy (n = 694) or DAPT (n = 693). Between 3 and 12 months of follow-up, the primary outcome (using Kaplan-Meier estimates) occurred in 9 patients (1.7%) in the P2Y12 inhibitor monotherapy group and in 16 patients (2.6%) in the DAPT group (absolute difference, -0.93 [1-sided 95% CI, -2.64 to 0.77] percentage points; P < .001 for noninferiority). For the major secondary outcomes (using Kaplan-Meier estimates), major adverse cardiac and cerebrovascular events occurred in 8 patients (1.5%) in the P2Y12 inhibitor monotherapy group and in 12 patients (2.0%) in the DAPT group (absolute difference, -0.49 [95% CI, -2.07 to 1.09] percentage points; P = .54). Major bleeding occurred in 1 patient (0.2%) in the P2Y12 inhibitor monotherapy group and in 5 patients (0.8%) in the DAPT group (absolute difference, -0.60 [95% CI, -1.33 to 0.12] percentage points; P = .10).

Conclusions and Relevance

In patients with coronary artery disease undergoing PCI with the latest generation of drug-eluting stents, P2Y12 inhibitor monotherapy after 3-month DAPT was not inferior to 12-month DAPT for net adverse clinical events. Considering the study population and lower-than-expected event rates, further research is required in other populations.

Trial Registration

ClinicalTrials.gov Identifier: NCT03447379.

The lysine methyltransferase SMYD2 facilitates neointimal hyperplasia by regulating the HDAC3-SRF axis

Coronary restenosis is an important cause of poor long-term prognosis in patients with coronary heart disease. Here, we show that lysine methyltransferase SMYD2 expression in the nucleus is significantly elevated in serum- and PDGF-BB-induced vascular smooth muscle cells (VSMCs), and in tissues of carotid artery injury-induced neointimal hyperplasia. Smyd2 overexpression in VSMCs (Smyd2-vTg) facilitates, but treatment with its specific inhibitor LLY-507 or SMYD2 knockdown significantly inhibits VSMC phenotypic switching and carotid artery injury-induced neointima formation in mice. Transcriptome sequencing revealed that SMYD2 knockdown represses the expression of serum response factor (SRF) target genes and that SRF overexpression largely reverses the inhibitory effect of SMYD2 knockdown on VSMC proliferation. HDAC3 directly interacts with and deacetylates SRF, which enhances SRF transcriptional activity in VSMCs. Moreover, SMYD2 promotes HDAC3 expression via tri-methylation of H3K36 at its promoter. RGFP966, a specific inhibitor of HDAC3, not only counteracts the pro-proliferation effect of SMYD2 overexpression on VSMCs, but also inhibits carotid artery injury-induced neointima formation in mice. HDAC3 partially abolishes the inhibitory effect of SMYD2 knockdown on VSMC proliferation in a deacetylase activity-dependent manner. Our results reveal that the SMYD2-HDAC3-SRF axis constitutes a novel and critical epigenetic mechanism that regulates VSMC phenotypic switching and neointimal hyperplasia.

Comparative efficacy of different Chinese patent medicines in preventing restenosis after percutaneous coronary intervention: a systematic review and Bayesian network meta-analysis of randomized clinical trials

Background: Chinese patent medicines (CMPs) have curative effectiveness in preventing coronary restenosis. However, the relative efficacy between different CPMs has not been sufficiently investigated. Methods: Randomized clinical trials were searched from electronic databases including PubMed, Web of Science, Cochrane Library, Embase, CNKI, VIP, WanFang, SinoMed, Chinese Clinical Trial Registry, and ClinicalTrials.gov. Bayesian network meta-analysis was performed to analyze CPMs' efficacy in preventing angiographic restenosis, recurrence angina, acute myocardial infarction, and target lesion revascularization after percutaneous coronary intervention. Results: This network meta-analysis included 47 trials with 5,077 patients evaluating 11 interventions. Regarding angiographic restenosis, the efficacy of CPMs (except Xuezhikang capsule) combined with standard treatment (Std) was superior to Std alone, and Guanxin Shutong capsule plus Std reduced the risk of angiographic restenosis by 76% (relative risk 0.24, 95% confidence interval 0.11-0.45, and very low to moderate certainty of evidence), most likely the best intervention. Fufang Danshen dripping pill combined with Std showed superiority over other interventions for relieving recurrence angina, which can reduce the risk by 83% (RR 0.17, 95% CI 0.04-0.51, very low to moderate certainty of evidence) compared to Std alone. In acute myocardial infarction after percutaneous coronary intervention, compared with Std alone, Danhong injection plus Std displayed a significant effect (RR 0.11, 95% CI 0.00-0.69, very low to moderate certainty of evidence) and was the best treatment probably. Chuanxiongqin tablet plus Std was the most effective treatment for reducing target lesion revascularization by 90% (RR 0.10, 95% CI 0.00-0.60, very low to moderate certainty of evidence) compared with Std alone. Conclusion: The results indicated that CPMs combined with Std reduced the risk of coronary restenosis after percutaneous coronary intervention. However, the results should be interpreted cautiously due to significant data limitations.

Hybrid interpenetrating network of polyester coronary stent with tunable biodegradation and mechanical properties

Poly(l-lactide) (PLLA) is an important candidate raw material of the next-generation biodegradable stent for percutaneous coronary intervention, yet how to make a polyester stent with sufficient mechanical strength and relatively fast biodegradation gets to be a dilemma. Herein, we put forward a hybrid interpenetrating network (H-IPN) strategy to resolve this dilemma. As such, we synthesize a multi-functional biodegradable macromer of star-like poly(d,l-lactide-co-ɛ-caprolactone) with six acrylate end groups, and photoinitiate it, after mixing with linear PLLA homopolymer, to trigger the free radical polymerization. The resultant crosslinked polymer blend is different from the classic semi-interpenetrating network, and partial chemical crosslinking occurs between the linear polymer and the macromer network. Combined with the tube blow molding and the postprocessing laser cutting, we fabricate a semi-crosslinked-polyester biodegradable coronary stent composed of H-IPN, which includes a physical network of polyester spherulites and a chemical crosslinking network of copolyester macromers and a part of homopolymers. Compared with the currently main-stream PLLA stent in research, this H-IPN stent realizes a higher and more appropriate biodegradation rate while maintaining sufficient radial strength. A series of polymer chemistry, polymer physics, polymer processing, and in vitro and in vivo biological assessments of medical devices have been made to examine the H-IPN material. The interventional implanting of the H-IPN stent into aorta abdominalis of rabbits and the follow-ups to 12 months have confirmed the safety and effectiveness.

Engineering Immunomodulatory Stents Using Zinc Ion-Lysozyme Nanoparticle Platform for Vascular Remodeling

Rapid endothelialization of cardiovascular materials can enhance the vascular remodeling performance. In this work, we developed a strategy for amyloid-like protein-assembly-mediated interfacial engineering to functionalize a biomimetic nanoparticle coating (BMC). Various groups (e.g., hydroxyl and carboxyl) on the BMC are responsible for chelating Zn2+ ions at the stent interface, similar to the glutathione peroxidase-like enzymes found in vivo. This design could reproduce the release of therapeutic nitric oxide gas (NO) and an aligned microenvironment nearly identical with that of natural vessels. In a rabbit abdominal aorta model, BMC-coated stents promoted vascular healing through rapid endothelialization and the inhibition of intimal hyperplasia in the placement sites at 4, 12, and 24 weeks. Additionally, better anticoagulant activity and immunomodulation in the BMC stents were also confirmed, and vascular healing was mainly dependent on cell signaling through the cyclic guanosine monophosphate-protein kinase G (cGMP-PKG) cascade. Overall, a metal-polypeptide-coated stent was developed on the basis of its detailed molecular mechanism of action in vascular remodeling.

In Situ Deposition of Drug and Gene Nanoparticles on a Patterned Supramolecular Hydrogel to Construct a Directionally Osteochondral Plug

The integrated repair of bone and cartilage boasts advantages for osteochondral restoration such as a long-term repair effect and less deterioration compared to repairing cartilage alone. Constructing multifactorial, spatially oriented scaffolds to stimulate osteochondral regeneration, has immense significance. Herein, targeted drugs, namely kartogenin@polydopamine (KGN@PDA) nanoparticles for cartilage repair and miRNA@calcium phosphate (miRNA@CaP) NPs for bone regeneration, were in situ deposited on a patterned supramolecular-assembled 2-ureido-4 [lH]-pyrimidinone (UPy) modified gelation hydrogel film, facilitated by the dynamic and responsive coordination and complexation of metal ions and their ligands. This hydrogel film can be rolled into a cylindrical plug, mimicking the Haversian canal structure of natural bone. The resultant hydrogel demonstrates stable mechanical properties, a self-healing ability, a high capability for reactive oxygen species capture, and controlled release of KGN and miR-26a. In vitro, KGN@PDA and miRNA@CaP promote chondrogenic and osteogenic differentiation of mesenchymal stem cells via the JNK/RUNX1 and GSK-3β/β-catenin pathways, respectively. In vivo, the osteochondral plug exhibits optimal subchondral bone and cartilage regeneration, evidenced by a significant increase in glycosaminoglycan and collagen accumulation in specific zones, along with the successful integration of neocartilage with subchondral bone. This biomaterial delivery approach represents a significant toward improved osteochondral repair.

Pathological Analysis of Medial and Intimal Calcification in Lower Extremity Artery Disease: Impact of Hemodialysis

Background

The prevalence and degree of lower extremity artery disease in hemodialysis (HD) patients is higher than in the general population. However, the pathological features have not yet been evaluated.

Objectives

The aim of the study was: 1) to compare lesion characteristics of lower extremity artery disease in HD vs non-HD patients; and 2) to determine factors associated with severe medial calcification.

Methods

Seventy-seven lower limb arteries were assessed from 36 patients (median age 77 years; 23 men; 21 HD and 15 non-HD) who underwent autopsy or lower limb amputation. Arteries were serially cut at 3- to 4-mm intervals creating 2,319 histological sections. Morphometric analysis and calcification measurements were performed using ZEN software. Calcification with a circumferential angle (arc) ≥180° was defined as severe calcification. Multivariable logistic regression was used to identify risk factors for severe medial calcification.

Results

The degree of the medial calcification arc was significantly higher in the HD group compared to the non-HD group (P < 0.0001). In the multivariable analysis, HD was associated with severe medial calcification in below-the-knee lesions (OR: 17.1; P = 0.02). The degree of intimal calcification in above-the-knee lesions was also significantly higher in HD patients with a higher prevalence of advanced atherosclerotic plaque (P = 0.02). The prevalence of severe bone formation was more common in the HD patients (P = 0.01).

Conclusions

Hemodialysis patients demonstrated a higher degree of medial and intimal calcification compared with non-HD patients. The difference was more prominent in the medial calcification of below-the-knee lesions.

Poor Below Knee Runoff Impacts Femoropopliteal Stent Failure and Fluoropolymer Antithrombotic Effect in Healthy Swine Model

OBJECTIVE

Poor below knee (BTK) runoff is a predictor of stent failure after endovascular femoropopliteal artery treatment; however, lack of pathological evaluation has prevented characterisation of stent failure. The study aimed to investigate the impact of poor BTK runoff and the antithrombotic effect of the polymer of fluoropolymer coated paclitaxel eluting stents (FP-PESs) in a healthy swine femoropopliteal artery model.

METHODS

FP-PESs and bare metal stents (BMSs) and FP-PES and polymer free paclitaxel coated stents (PF-PCSs) were implanted in the bilateral femoral arteries of healthy swine (n = 6, respectively) following coil embolisation in both tibial arteries to induce poor BTK runoff. Histological assessment and intravascular imaging device evaluation were performed at one month. The Japanese Association for Laboratory Animal Science approved the study protocol (reference number: IVT22-90).

RESULTS

Optical coherence tomography showed significantly lower percent area stenosis in FP-PES compared with BMS (37.3%, [interquartile range (IQR), 25.6 - 54.3] % vs. 92.5% [IQR, 75.5 - 96.1] %, respectively, p = .031), and PF-PCS (8.3% [IQR, 4.5 - 27.0] % vs. 31.2% [IQR, 23.3 - 52.2] %, respectively, p = .031). Histopathological evaluation demonstrated that thin fibrin attachment without re-stenosis was the most dominant neointimal tissue characteristic in FP-PES. On the other hand, neointimal tissue characteristics with significant restenosis of BMS and PF-PCS were mainly organising or organised thrombus.

CONCLUSION

Organising and or organised thrombus attachment due to poor BTK runoff was the main cause of in stent restenosis of the swine femoral artery. FP-PES demonstrated the least percent area stenosis, suggesting the importance of the antithrombotic effect of polymer.

A novel noble metal stent coating reduces in vitro platelet activation and acute in vivo thrombosis formation: a blinded study

Inherent to any stenting procedure is the prescription of dual antiplatelet therapy (DAPT) to reduce the platelet response. Clinical guidelines recommend 6-12 months of DAPT, depending on stent type, clinical picture and patient factors. Our hypothesis is that a nanostructured noble metal coating has the potential to reduce protein deposition and platelet activation. These effects would reduce subsequent thrombo-inflammatory reactions, potentially mitigating the need for an extensive DAPT in the acute phase. Here, a noble metal nanostructure coating on stents is investigated. Twelve pigs underwent endovascular implantation of coated and non-coated stents for paired comparisons in a blinded study design. The non-coated control stent was placed at the contralateral corresponding artery. Volumetric analysis of angiographic data, performed by a treatment blinded assessor, demonstrated a significant thrombus reduction for one of the coatings compared to control. This effect was already seen one hour after implantation. This finding was supported by in vitro data showing a significant reduction of coagulation activation in the coated group. This novel coating shows promise as an implant material addition and could potentially decrease the need for DAPT in the early phases of stent implementation.

Phase-transited lysozyme nanofilm with co-immobilized copper ion and heparin as cardiovascular stent multifunctional coating

Cardiovascular metal stents have shown potential in the treatment of coronary artery disease using percutaneous coronary intervention. However, thrombosis, endothelialization, and new atherosclerosis after stent implantation remain unsolved problems. Herein, a multifunctional coating material based on phase-transited lysozyme was developed to promote stent endothelialization and simultaneously reduce thrombus events by embedding moieties of heparin and co-immobilized copper ions for in-situ catalyzing nitric oxide (NO) generation. The lysozyme-based biomimetic coating is compatible with blood and enables facile loading and sustainable release of copper ions to produce NO with donors via catalytic reaction. The novel coating strategy displayed several bio-effects of anti-thrombosis; it synergistically promoted endothelial cell growth and inhibited smooth muscle cell growth. Thus, this systemic in vitro study will provide a foundation for developing multifunctional cardiovascular stents in clinical settings.

Biosynthetic Plastics as Tunable Elastic and Visible Stent with Shape-Memory to Treat Biliary Stricture

Common biliary tract is ≈4 mm in diameter to deliver bile from liver to small intestine to help digestion. The abnormal narrowing leads to severe symptoms such as pain and nausea. Stents are an effective treatment. Compared with non-degradable stents which require repeated removal, biodegradable stents have the advantage of reducing secondary injury related to endoscopic operation and patient burden. However, current biodegradable materials may cause tissue hyperplasia and the treatment method does not target etiology of stricture. So recurrence rates after biodegradable stent implantation are still high. Here, a biodegradable helical stent fabricated from biosynthetic P(3HB-co-4HB) is reported. Tunable properties can be acquired through altering culture substrates. Stent shows shape memory in various solvents. The stent has an optimized design with helical structure and outer track. The self-expanding of helical structure and double drainage realized by outer track greatly improve drainage of bile. Importantly, stent-loading triamcinolone acetonide can inhibit proliferation of fibroblasts and reduce incidence of restricture. Therapeutic effect is also demonstrated in minipigs with biliary stricture. The results of minipig experiments show that biliary duct in treatment group is unobstructed and tissue hyperplasia is effectively inhibited.

Non-Psychoactive Phytocannabinoids Inhibit Inflammation-Related Changes of Human Coronary Artery Smooth Muscle and Endothelial Cells

Atherosclerosis is associated with vascular smooth muscle cell proliferation, chronic vascular inflammation, and leukocyte adhesion. In view of the cardioprotective effects of cannabinoids described in recent years, the present study investigated the impact of the non-psychoactive phytocannabinoids cannabidiol (CBD) and tetrahydrocannabivarin (THCV) on proliferation and migration of human coronary artery smooth muscle cells (HCASMC) and on inflammatory markers in human coronary artery endothelial cells (HCAEC). In HCASMC, CBD and THCV at nontoxic concentrations exhibited inhibitory effects on platelet-derived growth factor-triggered proliferation (CBD) and migration (CBD, THCV). When interleukin (IL)-1β- and lipopolysaccharide (LPS)-stimulated HCAEC were examined, both cannabinoids showed a concentration-dependent decrease in the expression of vascular cell adhesion molecule-1 (VCAM-1), which was mediated independently of classical cannabinoid receptors and was not accompanied by a comparable inhibition of intercellular adhesion molecule-1. Further inhibitor experiments demonstrated that reactive oxygen species, p38 mitogen-activated protein kinase activation, histone deacetylase, and nuclear factor κB (NF-κB) underlie IL-1β- and LPS-induced expression of VCAM-1. In this context, CBD and THCV were shown to inhibit phosphorylation of NF-κB regulators in LPS- but not IL-1β-stimulated HCAEC. Stimulation of HCAEC with IL-1β and LPS was associated with increased adhesion of monocytes, which, however, could not be significantly abolished by CBD and THCV. In summary, the results highlight the potential of the non-psychoactive cannabinoids CBD and THCV to regulate inflammation-related changes in HCASMC and HCAEC. Considering their effect on both cell types studied, further preclinical studies could address the use of CBD and THCV in drug-eluting stents for coronary interventions.

Faster smooth muscle cell coverage in ultrathin-strut drug-eluting stent leads to earlier re-endothelialization

Background: The ultrathin-strut drug-eluting stent (DES) has shown better clinical results than thin- or thick-strut DES. We investigated if re-endothelialization was different among three types of DES: ultrathin-strut abluminal polymer-coated sirolimus-eluting stent (SES), thin-strut circumferential polymer-coated everolimus-eluting stent (EES), and thick-strut polymer-free biolimus-eluting stent (BES) to gain insight into the effect of stent design on promoting vascular healing. Methods: After implanting three types of DES in the coronary arteries of minipigs, we performed optical coherence tomography (OCT) at weeks 2, 4, and 12 (n = 4, each). Afterward, we harvested the coronary arteries and performed immunofluorescence for endothelial cells (ECs), smooth muscle cells (SMCs), and nuclei. We obtained 3D stack images of the vessel wall and reconstructed the en face view of the inner lumen. We compared re-endothelialization and associated factors among the different types of stents at different time points. Results: SES showed significantly faster and denser re-endothelialization than EES and BES at weeks 2 and 12. Especially in week 2, SES elicited the fastest SMC coverage and greater neointimal cross-sectional area (CSA) compared to EES and BES. A strong correlation between re-endothelialization and SMC coverage was observed in week 2. However, the three stents did not show any difference at weeks 4 and 12 in SMC coverage and neointimal CSA. At weeks 2 and 4, SMC layer morphology showed a significant difference between stents. A sparse SMC layer was associated with denser re-endothelialization and was significantly higher in SES. Unlike the sparse SMC layer, the dense SMC layer did not promote re-endothelialization during the study period. Conclusion: Re-endothelialization after stent implantation was related to SMC coverage and SMC layer differentiation, which were faster in SES. Further investigation is needed to characterize the differences among the SMCs and explore methods for increasing the sparse SMC layer in order to improve stent design and enhance safety and efficacy.

A technology evaluation of the Onyx Frontier drug-eluting stent

INTRODUCTION

Onyx FrontierTM represents the latest iteration within the family of zotarolimus-eluting stents (ZES), designed for the treatment of coronary artery disease. Approval by the Food and Drug Administration was granted in May 2022, and Conformité Européenne marking followed in August 2022.

AREAS COVERED

We hereby review the principal design features of Onyx Frontier, highlighting differences and similarities with other currently available drug-eluting stents. In addition, we focus on the refinements of this newest platform as compared with previous ZES versions, including the attributes yielding its exceptional crossing profile and deliverability. The clinical implications related to both its newest and inherited characteristics will be discussed.

EXPERT OPINION

The nuances of the latest Onyx Frontier, together with the continuous refinement previously witnessed throughout the development of ZES, lead to a latest generation device ideal for a diverse spectrum of clinical and anatomical scenarios. In particular, its peculiarities will be of benefit in the settings often offered by a progressively aging population, such as high bleeding risk patients and complex coronary lesions.

Mechanisms of Xuefu Zhuyu Decoction in the treatment of coronary heart disease based on integrated metabolomics and network pharmacology approach

Coronary heart disease (CHD) has become the leading cause of mortality, morbidity, and disability worldwide. Though the therapeutic effect of Xuefu Zhuyu Decoction (XFZY) on CHD has been demonstrated in China, the active ingredients and molecular mechanisms of XFZY have not been elucidated. The purpose of the current study is to explore the molecular mechanisms of XFZY in the treatment of CHD via network pharmacology, metabolomics, and experimental validation. First, we established a CHD rat model by permanently ligating the left anterior descending coronary artery (LAD), and evaluated the therapeutic effect of XFZY by hemorheology and histopathology. Second, network pharmacology was employed to screen the active ingredients and potential targets of XFZY for the treatment of CHD. Metabolomic was applied to identify the molecules present in the serum after XFZY treatment. Third, the results of network pharmacology and metabolomics were further analyzed by Cytoscape to elucidate the core ingredients and pathways. Finally, the obtained key pathways were verified by transmission electron microscopy and immunofluorescence assay. The results showed that XFZY was effective in the treatment of CHD in the rat model, and the highest dose exerted the best effect. Network pharmacology analysis revealed 215 active ingredients and 129 key targets associated with XFZY treatment of CHD. These targets were enriched in pathways of cancer, lipid and atherosclerosis, fluid shear stress and atherosclerosis, proteoglycans in cancer, chemical carcinogenesis - receptor activation, HIF-1 signaling, et al. Serum metabolomic identified 1081 metabolites involved in the therapeutic effect of XFZY on CHD. These metabolites were enriched in taurine and hypotaurine metabolism, histidine metabolism, retrograde endocannabinoid signaling pathways, et al. Cytoscape analysis combining the data from serum metabolomic and network pharmacology revealed that energy metabolism as the core pathway for XFZY treatment of CHD. Electron microscope observation identified changes in the level of autophagy in the mitochondrial structure of cardiomyocytes. Immunofluorescence assay showed that the expression levels of autophagy-related proteins LC3-B and P62/SQSTM1 were consistent with the levels of autophagy observed in mitochondria. In conclusion, our findings suggest that the possible mechanisms of XFZY in the treatment of CHD are reducing the level of autophagy, improving energy metabolism, and maintaining mitochondrial homeostasis in cardiomyocytes. Our study also shows that the combined strategies of network pharmacology, metabolomics, and experimental validation may provide a powerful approach for TCM pharmacology study.

Biopolymeric Coatings for Local Release of Therapeutics from Biomedical Implants

The deployment of structures that enable localized release of bioactive molecules can result in more efficacious treatment of disease and better integration of implantable bionic devices. The strategic design of a biopolymeric coating can be used to engineer the optimal release profile depending on the task at hand. As illustrative examples, here advances in delivery of drugs from bone, brain, ocular, and cardiovascular implants are reviewed. These areas are focused to highlight that both hard and soft tissue implants can benefit from controlled localized delivery. The composition of biopolymers used to achieve appropriate delivery to the selected tissue types, and their corresponding outcomes are brought to the fore. To conclude, key factors in designing drug-loaded biopolymeric coatings for biomedical implants are highlighted.

Histological evaluation of vascular changes after excimer laser angioplasty for neointimal formation after bare-metal stent implantation in rabbit iliac arteries

BACKGROUND

Excimer laser is used to treat coronary artery disease, especially in case of lesions with thrombus and in-stent restenosis (ISR). However, there are no in vivo preclinical studies that have evaluated the pathological reactions of the vessel wall after excimer laser ablation.

METHODS

Bare-metal stents were placed in the external iliac arteries of six healthy rabbits. Twenty-eight days later, excimer laser ablation was performed with low-power (45 (fluency)/25 (rate)) in one side, and high-power (60/40) in the opposite side, followed by optical coherence tomography (OCT) evaluation. Rabbits were sacrificed 15 min after the procedure, and histological assessment was performed.

RESULTS

Morphometry analysis of OCT showed similar stent and lumen size between low-power and high-power group. Histological evaluation suggested endothelial cell loss, fibrin deposition, and tissue loss. The low-power group showed significantly less pathological changes compared with the high-power group: angle of endothelial cell loss, 32.4° vs. 191.7° (interquartile range, 8.8°-131.7° vs. 125.7°-279.5°; p < 0.01); fibrin deposition, 1.1° vs. 59.6° (0.0°-70.4° vs. 31.4°-178.4°; p = 0.03); and tissue loss 0.0° vs. 18.2° (0.0°-8.7° vs. 0.0°-42.7°; p = 0.03).

CONCLUSIONS

The pathological changes in neointima were more prominent after high-power excimer laser ablation than after low-power excimer laser. To improve safety in clinical practice, understanding the pathological changes of tissues after excimer laser in lesions with ISR is essential.

"Spongy skin" as a robust strategy to deliver 4-octyl itaconate for conducting dual-regulation against in-stent restenosis

The valid management of inflammation and precise inhibition of smooth muscle cells (SMCs) is regarded as a promising strategy for regulating vascular responses after stent implantation, yet posing huge challenges to current coating constructions. Herein, we proposed a spongy cardiovascular stent for the protective delivery of 4-octyl itaconate (OI) based on a "spongy skin" approach, and revealed the dual-regulation effects of OI for improving vascular remolding. We first constructed a "spongy skin" onto poly-l-lactic acid (PLLA) substrates, and realized the protective loading of OI with the highest dosage of 47.9 μg/cm². Then, we verified the remarkable inflammation mediation of OI, and surprisingly revealed that the OI incorporation specifically inhibited SMC proliferation and phenotype switching, which contributed to the competitive growth of endothelial cells (EC/SMC ratio ∼ 5.1). We further demonstrated that OI at a concentration of 25 μg/mL showed significant suppression of the TGF-β/Smad pathway of SMCs, leading to the promotion of contractile phenotype and reduction of extracellular matrix. In vivo evaluation indicated that the successful delivery of OI fulfilled the inflammation regulation and SMCs inhibition, therefore suppressing the in-stent restenosis. This "spongy skin" based OI eluting system may serve as a new strategy for improving vascular remolding, and provides a potential concept for the treatment of cardiovascular diseases.

Evaluation of coronary stents: A review of types, materials, processing techniques, design, and problems

In the world, one of the leading causes of death is coronary artery disease (CAD). There are several ways to treat this disease, and stenting is currently the most appropriate way in many cases. Nowadays, the use of stents has rapidly increased, and they have been introduced in various models, with different geometries and materials. To select the most appropriate stent required, it is necessary to have an analysis of the mechanical behavior of various types of stents. The purpose of this article is to provide a complete overview of advanced research in the field of stents and to discuss and conclude important studies on different topics in the field of stents. In this review, we introduce the types of coronary stents, materials, stent processing technique, stent design, classification of stents based on the mechanism of expansion, and problems and complications of stents. In this article, by reviewing the biomechanical studies conducted in this field and collecting and classifying their results, a useful set of information has been presented to continue research in the direction of designing and manufacturing more efficient stents, although the clinical-engineering field still needs to continue research to optimize the design and construction. The optimum design of stents in the future is possible by simulation and using numerical methods and adequate knowledge of stent and artery biomechanics.

A Biocompatible 4D Printing Shape Memory Polymer as Emerging Strategy for Fabrication of Deployable Medical Devices

The rapid development of 4D printing provides a potential strategy for the fabrication of deployable medical devices (DMD). The minimally invasive surgery to implant the DMD into the body is critical, 4D printing DMD allows the well-defined device to be implanted with a high-compacted shape and transformed into their designed shape to meet the requirement. Herein, a 4D printing tissue engineering material is developed with excellent biocompatibility and shape memory effect based on the photocrosslinked polycaprolactone (PCL). The fast thiol-acrylate click reaction is applied for photocrosslinking of the acrylates capped star polymer (s-PCL-MA) with poly-thiols, that enable the 3D printing for the DMD fabrication. The cell viability, erythrocyte hemolysis, and platelet adhesion results indicate the excellent biocompatibility of the 4D printing polymer, especially the biological subcutaneous implantation results confirm the promote tissue growth and good histocompatibility. A 4D printing stent with deformable shape and recovery at a temperature close to human body temperature demonstrated the potential application as DMD. In addition, the everolimus is loaded to the polymer (ps1-PCL) through host-guest coordination with β-cyclodextrin as the core of the star polymer, which shows sustained drug release and improved body's inflammatory response.

Early vascular healing after neXt-generation drug-eluting stent implantation in Patients with non-ST Elevation acute Coronary syndrome based on optical coherence Tomography guidance and evaluation (EXPECT): study protocol for a randomized controlled trial

Background

There is limited evidence about vessel wall healing response following implantation of next-generation drug-eluting stents (DES) in patients admitted with a non-ST elevation acute coronary syndrome (NSTE-ACS). Cumulative data indicate that optical coherence tomography (OCT) imaging can optimize percutaneous coronary intervention results and expedite stent endothelialization in the general population but there is lack of data in NSTE-ACS patients.

Methods

The EXPECT study is an investigator-initiated, prospective, randomized trial to assess early vascular healing response following next-generation DES implantation in patients admitted with NSTE-ACS based on OCT guidance and evaluation. Sixty patients are randomized at 1:1:1 ratio to OCT-guided percutaneous coronary intervention (PCI) with 3-month follow-up OCT imaging (O3 group, n = 20), to angiography-guided PCI with 3-month follow-up OCT imaging (A3 group, n = 20) and to angiography-guided PCI with 6-month follow-up OCT imaging (A6 group, n = 20). The primary endpoint of the study is stent strut coverage rate at 3- or 6- month follow-up in the studied groups. The secondary endpoints of the study include OCT imaging endpoints, clinical endpoints, and molecular biology endpoints at the different time points. The clinical endpoints comprised of major cardiovascular adverse events and individual components. The molecular biology endpoints comprised of lipid levels and the levels of inflammatory indicators.

Discussion

The findings of the EXPECT study are anticipated to provide novel insights into vessel wall healing in NSTE-ACS population following implantation of next-generation DES, underscore the value of OCT imaging in expediting strut coverage in this setting, and explore the potential of an early discontinuation of dual antiplatelet therapy (DAPT) in this population.

Clinical Trial Registration

ClinicalTrials.gov, NCT04375319.

A word of caution: Early failure of Magmaris® bioresorbable stent after pulmonary artery stenting

Bioresorbable scaffolds (BRS) have been advocated as the fourth revolution in interventional cardiology medical devices with promising technology to improve the treatment of coronary artery disease with an event-free future. We describe the first reported use and early collapse of the Magmaris® Resorbable Magnesium Scaffold (RMS) stent (BIOTRONIK AG, Switzerland) to relieve left pulmonary artery severe stenosis in a newborn after the Norwood procedure. The stent collapse was detected 2 weeks after implantation and urgently treated with a balloon-expandable stent. This complication raises the alarm about the need to keep implanted RMS under scrutiny. The possibility of faster scaffold resorption in small babies or lack of sufficient radial force of RMS to resist acute vessel recoil has led to ineffective relief of branch pulmonary artery stenosis and failure to enable a safe short-term bridge to Stage II palliation.

Neointimal characteristic changes following drug-coated balloons in lesions with repeated revascularization

BACKGROUND

Since their emergence, drug-coated balloons (DCBs) have been used widely to treat in-stent lesions with coronary artery disease (CAD). However, despite their superior efficacy to balloon angioplasty, how DCBs affect neointimal characteristics is poorly understood.

OBJECTIVES

We aimed to assess the neointimal characteristic changes following DCB treatment.

METHODS

Using optical frequency domain imaging (OFDI), we serially observed the in-stent lesion site just after and 1 year after DCB angioplasty in 12 lesions of 11 patients with repeated revascularization. Neoatherosclerosis was defined as lipid-laden neointima with or without calcification in the stented lesion. Progression or regression of neoatherosclerosis, newly formed neointimal calcification, newly formed uncovered strut and newly formed evagination were assessed. Tiny tissue protrusion was also recorded as mushroom-like protrusion.

RESULTS

Underlying stents were first-generation (n = 5) or newer (n = 7) drug-eluting stents (DESs) with implantation durations ranging from 1 to 15 years (median 8 years). Surprisingly, two-thirds of the lesions (67%, 8 of 12) showed progression of neoatherosclerosis, while a quarter of lesions (25%, 3 of 12) showed regression of neoatherosclerosis. The maximal lipid arc increased from 122° to 174°. Newly formed neointimal calcification was observed in 2 of 12 lesions (16%). Newly formed uncovered struts (33%; 4 of 12) and newly formed evaginations (33%; 4 of 12) were not rare. Mushroom-like protrusion was found in a quarter of lesions (25%; 3 of 12).

CONCLUSION

Our study demonstrated that a considerable number of lesions showed varied neointimal characteristic changes in a small number of patients. Further studies in a larger population are needed to understand the clinical impact of these findings.

Recent advances in regenerative biomaterials

Nowadays, biomaterials have evolved from the inert supports or functional substitutes to the bioactive materials able to trigger or promote the regenerative potential of tissues. The interdisciplinary progress has broadened the definition of 'biomaterials', and a typical new insight is the concept of tissue induction biomaterials. The term 'regenerative biomaterials' and thus the contents of this article are relevant to yet beyond tissue induction biomaterials. This review summarizes the recent progress of medical materials including metals, ceramics, hydrogels, other polymers and bio-derived materials. As the application aspects are concerned, this article introduces regenerative biomaterials for bone and cartilage regeneration, cardiovascular repair, 3D bioprinting, wound healing and medical cosmetology. Cell-biomaterial interactions are highlighted. Since the global pandemic of coronavirus disease 2019, the review particularly mentions biomaterials for public health emergency. In the last section, perspectives are suggested: (i) creation of new materials is the source of innovation; (ii) modification of existing materials is an effective strategy for performance improvement; (iii) biomaterial degradation and tissue regeneration are required to be harmonious with each other; (iv) host responses can significantly influence the clinical outcomes; (v) the long-term outcomes should be paid more attention to; (vi) the noninvasive approaches for monitoring in vivo dynamic evolution are required to be developed; (vii) public health emergencies call for more research and development of biomaterials; and (viii) clinical translation needs to be pushed forward in a full-chain way. In the future, more new insights are expected to be shed into the brilliant field-regenerative biomaterials.

Durable polymer versus biodegradable polymer drug-eluting stents in patients with acute coronary syndrome undergoing complex percutaneous coronary intervention: a post hoc analysis of the HOST-REDUCE-POLYTECH-ACS trial

BACKGROUND

Comparative data of durable polymer (DP) versus biodegradable polymer (BP) drug-eluting stents (DES) are limited in patients presenting with acute coronary syndrome (ACS) undergoing complex percutaneous coronary intervention (PCI).

AIMS

We sought to evaluate the efficacy and safety of DP-DES and BP-DES in ACS patients receiving complex PCI.

METHODS

This study was a post hoc analysis of the HOST-REDUCE-POLYTECH-ACS trial. ACS patients were randomly assigned 1:1 to DP-DES or BP-DES in the HOST-REDUCE-POLYTECH-ACS trial. Complex PCI was defined as having at least 1 of the following features: ≥3 stents implanted, ≥3 lesions treated, total stent length ≥60 mm, bifurcation PCI with 2 stents, left main PCI, or heavy calcification. Patient-oriented (POCO, a composite of all-cause death, non-fatal myocardial infarction, and any repeat revascularisation) and device-oriented composite outcomes (DOCO, a composite of cardiac death, target vessel myocardial infarction, or target lesion revascularisation) were evaluated at 12 months.

RESULTS

Among 3,301 patients for whom full procedural data were available, 1,140 patients received complex PCI. Complex PCI was associated with higher risks of POCO and DOCO. The risks of POCO were comparable between DP-DES and BP-DES in both the complex (HR 0.87, 95% confidence interval [CI]: 0.57-1.33; p=0.522) and non-complex (HR 0.83, 95% CI: 0.56-1.24; p=0.368; p for interaction=0.884) PCI groups. DOCO was also not significantly different between DP-DES and BP-DES in both the complex (HR 0.74, 95% CI: 0.43-1.27; p=0.278) and non-complex (HR 0.67, 95% CI: 0.38-1.19; p=0.175; p for interaction=0.814) PCI groups.

CONCLUSIONS

In ACS patients, DP-DES and BP-DES showed similar clinical outcomes irrespective of PCI complexity.

Advances in the development of biodegradable coronary stents: A translational perspective

Implantation of cardiovascular stents is an important therapeutic method to treat coronary artery diseases. Bare-metal and drug-eluting stents show promising clinical outcomes, however, their permanent presence may create complications. In recent years, numerous preclinical and clinical trials have evaluated the properties of bioresorbable stents, including polymer and magnesium-based stents. Three-dimensional (3D) printed-shape-memory polymeric materials enable the self-deployment of stents and provide a novel approach for individualized treatment. Novel bioresorbable metallic stents such as iron- and zinc-based stents have also been investigated and refined. However, the development of novel bioresorbable stents accompanied by clinical translation remains time-consuming and challenging. This review comprehensively summarizes the development of bioresorbable stents based on their preclinical/clinical trials and highlights translational research as well as novel technologies for stents (e.g., bioresorbable electronic stents integrated with biosensors). These findings are expected to inspire the design of novel stents and optimization approaches to improve the efficacy of treatments for cardiovascular diseases.

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Bioresorbable stents can overcome the limitations of non-degradable stents.

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3D printing of shape-memory polymeric stents can lead to better clinical outcomes.

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Advances in Mg-, Fe- and Zn-based stents from a translational perspective.

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Electronic stents integrated with biosensors can covey stent status in real time.

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Development in the assessment of stent performance in vivo.

Multimodal effects of asymmetric coating of coronary stents by electrospinning and electrophoretic deposition

Drug-eluting stents (DESs) are drug-coated vascular implants that inhibit smooth muscle cell proliferation and limit in-stent re-stenosis. However, traditional DESs release a single drug into the blood and cannot cope with complex mechanisms in atherosclerosis and body responses. The present study aimed to develop a novel multimodal stent by fabricating asymmetric coating with electrophoretic deposition and electrospinning. Herein, we use heparin-loaded alginate (Hep/Alg) and atorvastatin calcium-loaded polyurethane (AtvCa/PU) coatings on the stent luminal and abluminal surfaces, respectively. Scanning electron microscopy (SEM) micrographs showed that the alginate coatings had uniformity and thin thickness. Meanwhile, the PU fibers were formed without beads, with an acceptable diameter and suitable mechanical properties. PU nanofiber revealed minimal degradation in a 1-month study. The release of AtvCa and Hep continued for 8 days without a significant initial burst release. None of the stent coatings were cytotoxic or hemolytic, and PU nanofibers supported the survival of human umbilical endothelial cells (HUVEC) with high adhesion and flattened morphologies. The results indicate that electrophoretic deposition and electrospinning have significant potential for achieving asymmetric coating on stents and a promising approach for dual drug release for multimodal effects in vascular stent applications.

Bioresorbable scaffolds vs. drug-eluting stents for patients with myocardial infarction: A systematic review and meta-analysis of randomized clinical trials

Objective

To compare the efficacy and safety of bioresorbable scaffolds (BRS) with drug-eluting stents (DES) in patients with myocardial infarction undergoing percutaneous coronary interventions (PCI).

Methods

We performed a systematic review and meta-analysis of randomized controlled trials (RCTs) comparing BRS with DES on clinical outcomes with at least 12 months follow-up. Electronic databases of PubMed, CENTRAL, EMBASE, and Web of Science from inception to 1 March 2022 were systematically searched to identify relevant studies. The primary outcome of this study was the device-oriented composite endpoint (DOCE) consisting of cardiac death, target-vessel myocardial infarction, and target lesion revascularization. Secondary outcomes were a composite of major adverse cardiac events (MACE, all-cause death, target-vessel myocardial infarction, or target vessel revascularization) and the patient-oriented composite endpoint (POCE, defined as a composite of all-cause death, myocardial infarction, or revascularization). The safety outcomes were definite/probable device thrombosis and adverse events.

Results

Four randomized clinical trials including 803 participants with a mean age of 60.5 ± 10.8 years were included in this analysis. Patients treated with BRS had a higher risk of the DOCE (RR 1.62, 95% CI: 1.02–2.57, P = 0.04) and MACE (RR 1.77, 95% CI: 1.02–3.08, P = 0.04) compared with patients treated with DES. No significant difference on the POCE (RR 1.33, 95% CI: 0.89–1.98, P = 0.16) and the definite/probable device thrombosis (RR 1.31, 95% CI: 0.46–3.77, P = 0.61) were observed between BRS and DES. No treatment-related serious adverse events were reported.

Conclusion

BRS was associated with a higher risk of DOCE and MACE compared with DES in patients undergoing PCI for myocardial infarction. Although this seems less effective in preventing DOCE, BRS appears as safe as DES.

Systematic review registration

[https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=321501], identifier [CRD 42022321501].

Aptamer-based applications for cardiovascular disease

Cardiovascular disease (especially atherosclerosis) is a major cause of death worldwide, and novel diagnostic tools and treatments for this disease are urgently needed. Aptamers are single-stranded oligonucleotides that specifically recognize and bind to the targets by forming unique structures in vivo, enabling them to rival antibodies in cardiac applications. Chemically synthesized aptamers can be readily modified in a site-specific way, so they have been engineered in the diagnosis of cardiac diseases and anti-thrombosis therapeutics. Von Willebrand Factor plays a unique role in the formation of thrombus, and as an aptamer targeting molecule, has shown initial success in antithrombotic treatment. A combination of von Willebrand Factor and nucleic acid aptamers can effectively inhibit the progression of blood clots, presenting a positive diagnosis and therapeutic effect, as well as laying a novel theory and strategy to improve biocompatibility paclitaxel drug balloon or implanted stent in the future. This review summarizes aptamer-based applications in cardiovascular disease, including biomarker discovery and future management strategy. Although relevant applications are relatively new, the significant advancements achieved have demonstrated that aptamers can be promising agents to realize the integration of diagnosis and therapy in cardiac research.

Biofunctionalization of cardiovascular stents to induce endothelialization: Implications for in- stent thrombosis in diabetes

Stent thrombosis remains one of the main causes that lead to vascular stent failure in patients undergoing percutaneous coronary intervention (PCI). Type 2 diabetes mellitus is accompanied by endothelial dysfunction and platelet hyperactivity and is associated with suboptimal outcomes following PCI, and an increase in the incidence of late stent thrombosis. Evidence suggests that late stent thrombosis is caused by the delayed and impaired endothelialization of the lumen of the stent. The endothelium has a key role in modulating inflammation and thrombosis and maintaining homeostasis, thus restoring a functional endothelial cell layer is an important target for the prevention of stent thrombosis. Modifications using specific molecules to induce endothelial cell adhesion, proliferation and function can improve stents endothelialization and prevent thrombosis. Blood endothelial progenitor cells (EPCs) represent a potential cell source for the in situ-endothelialization of vascular conduits and stents. We aim in this review to summarize the main biofunctionalization strategies to induce the in-situ endothelialization of coronary artery stents using circulating endothelial stem cells.