Novel Multifunctional Nanomatrix Reduces Inflammation in Dynamic Conditions in Vitro and Dilates Arteries ex Vivo

Alexander, Grant C.,Vines, Jeremy B.,Hwang, Patrick,Kim, Teayoun,Kim, Jeong-a,Brott, Brigitta C.,Yoon, Young-Sup,Jun, Ho-Wook American Chemical Society 2016 ACS APPLIED MATERIALS & INTERFACES Vol.8 No.8

<P>Inflammatory responses play a critical role in tissue implant interactions, often limiting current implant utility. This is particularly true for cardiovascular devices. Existing stent technology does little to avoid or mitigate inflammation or to influence the vasomotion of the artery after implantation. We have developed a novel endothelium-mimicking nanomatrix composed of peptide amphiphiles that enhances endothelialization while decreasing both smooth muscle cell proliferation and platelet adhesion. Here, we evaluated whether the nanomatrix could prevent inflammatory responses under static and physiological flow conditions. We found that the nanomatrix reduced monocyte adhesion to endothelial cells and expression of monocyte inflammatory genes (TNF-alpha, MCP-1, IL-1 beta, and IL-6). Furthermore, the nitric-oxide releasing nanomatrix dramatically attenuated TNF-alpha-stimulated inflammatory responses as demonstrated by significantly reduced monocyte adhesion and inflammatory gene expression in both static and physiological flow conditions. These effects were abolished by addition of a nitric oxide scavenger. Finally, the nanomatrix stimulated vasodilation in intact rat mesenteric arterioles after constriction with phenylephrine, demonstrating the bioavailability and bioactivity of the nanomatrix, as well as exhibiting highly desired release kinetics. These results demonstrate the clinical potential of this nanomatrix by both preventing inflammatory responses and promoting vasodilation, critical improvements in stent and cardiovascular device technology.</P>

Biomimetic Prohealing Nanomatrix for Stent and Atherosclerosis Model

Xixi Zhang,Jun Chen,Grant C. Alexander,Patrick TJ. Hwang,Peter G. Anderson,Young-Sup Yoon,Brigitta C. Brott,Ho-Wook Jun(전호욱) 한국고분자학회 2021 한국고분자학회 학술대회 연구논문 초록집 Vol.46 No.1

Topic 1 for Stent coating: Cardiovascular disease is the number one cause of death worldwide. Stents are the most commonly implanted devices to effectively treat cardiovascular disease. However, bare metal stent (BMS) remains limited by relatively high rates of in-stent restenosis and the accompanying extracellular matrix deposition. Thus, drug-eluting stents (DES) have been developed to reduce restenosis. Although these efforts were successful, DES has its own set of shortcomings: late stent thrombosis, inflammation and delayed re-endothelialization. To address these issues, we developed a novel prohealing multifunctional stent coating: a nitric oxide (NO)-releasing endothelium-mimicking nanomatrix composed of the biomaterial- Peptide Amphiphile (PA). We evaluated the safety and efficacy of the novel coated stent in the rabbit iliac artery balloon injury model and compared with commercially available BMS and DES. The goal is to demonstrate the advantages of the nanomatrix coating which could enhance re-endothelialization, while reduce restenosis, inflammation, and thrombosis. We hypothesize that the prohealing multifunctional nanomatrix coated stent has several strengths compared with BMS and DES: 1) promoted re-endothelialization; 2) less restenosis than BMS; and 3) less inflammation and thrombosis than DES. Topic 2 for atherosclerosis model: Atherosclerosis is the main cause of cardiovascular disease. To evaluate therapeutics for treating atherosclerosis, in vivo and in vitro atherosclerosis models are developed. However, those atherosclerosis models have their own limitations. In vivo models, like pig and non-human primates, can develop lesions in coronary arteries, however, inducing atherosclerosis in them requires high cholesterol intake, long induction time, gene knock-out, and high expense. Although mouse models are the predominant models used in the labs, however, most of the currently mouse models show different plaque structure and genome from that of human. In vitro models are also used for evaluation due to their low cost; however, most of the those models are not generated following the pathogenesis of human atherosclerosis and are two-dimensional (2D) models which are limited to static culture in tissue culture plate and unable to provide three-dimensional (3D) tissue structures with proper functions. Thus, the main goal of this proposal is to develop an innovative biologically inspired 3D in vitro platform – tissue engineered atherosclerosis model (TEAM), featured with endothelial dysfunction, macrophages, and foam cells, following the pathogenesis of human atherosclerosis with low cost.

Evaluation of ciprofloxacin and metronidazole encapsulated biomimetic nanomatrix gel on Enterococcus faecalis and Treponema denticola

Sagar N Kaushik,Jessica Scoffield,Adinarayana Andukuri,Grant C Alexander,Taneidra Walker,김석곤,최성철,Brigitta C Brott,Paul D Eleazer,이진용,Hui Wu,Noel K Childers,Ho-Wook Jun,박재홍,Kyounga Cheon 한국생체재료학회 2015 생체재료학회지 Vol.19 No.2

Background: A triple antibiotic mixture (ciprofloxacin; CF, metronidazole; MN, and minocycline; MC) has been used for dental root canal medicaments in pulp regeneration therapy. However, tooth discolorations, cervical root fractures, and inadequate pulp-dentin formation have been reported due to the triple antibiotic regimen. Therefore, an antibiotic encapsulated biomimetic nanomatrix gel was developed to minimize the clinical limitations and maximize a natural healing process in root canal infections. In this study, minimal bacterial concentrations (MBC) of the selected antibiotics (CF and MN) were tested in 14 representative endodontic bacterial species. Then MBC of each CF and MN were separately encapsulated within the injectable self-assembled biomimetic nanomatrix gel to evaluate antibacterial level on Enterococcus faecalis and Treponema denticola. Results: Antibiotic concentrations lower than 0.2 μg/mL of CF and MN demonstrated antibacterial activity on the 14 endodontic species. Furthermore, 6 different concentrations of CF and MN separately encapsulated with the injectable self-assembled biomimetic nanomatrix gel demonstrated antibacterial activity on Enterococcus faecalis and Treponema denticola at the lowest tested concentration of 0.0625 μg/mL. Conclusions: These results suggest that each CF and MN encapsulated within the injectable self-assembled biomimetic nanomatrix gel demonstrated antibacterial effects, which could be effective for the root canal disinfection while eliminating MC. In the long term, the antibiotic encapsulated injectable self-assembled biomimetic nanomatrix gel can provide a multifunctional antibiotic delivery method with potential root regeneration. Further studies are currently underway to evaluate the effects of combined CF and MN encapsulated within the injectable self-assembled biomimetic nanomatrix gel on clinical samples.

Evaluation of the effect of expansion and shear stress on a self-assembled endothelium mimicking nanomatrix coating for drug eluting stents <i>in vitro</i> and <i>in vivo</i>

Andukuri, Adinarayana,Min, IlJae,Hwang, Patrick,Alexander, Grant,Marshall, Lauren E,Berry, Joel L,Wick, Timothy M,Joung, Yoon Ki,Yoon, Young-Sup,Brott, Brigitta C,Han, Dong Keun,Jun, Ho-Wook IOP Publishing 2014 Biofabrication Vol.6 No.3

<P>Coating stability is increasingly recognized as a concern impacting the long-term effectiveness of drug eluting stents (DES). In particular, unstable coatings have been brought into focus by a recently published report (Denardo et al 2012 J. Am. Med. Assoc. 307 2148-50). Towards the goal of overcoming current challenges of DES performance, we have developed an endothelium mimicking nanomatrix coating composed of peptide amphiphiles that promote endothelialization, but limit smooth muscle cell proliferation and platelet adhesion. Here, we report a novel water evaporation based method to uniformly coat the endothelium mimicking nanomatrix onto stents using a rotational coating technique, thereby eliminating residual chemicals and organic solvents, and allowing easy application to even bioabsorbable stents. Furthermore, the stability of the endothelium mimicking nanomatrix was analyzed after force experienced during expansion and shear stress under simulated physiological conditions. Results demonstrate uniformity and structural integrity of the nanomatrix coating. Preliminary animal studies in a rabbit model showed no flaking or peeling, and limited neointimal formation or restenosis. Therefore, it has the potential to improve the clinical performance of DES by providing multifunctional endothelium mimicking characteristics with structural integrity on stent surfaces.</P>

A multi-targeting bionanomatrix coating to reduce capsular contracture development on silicone implants

Patrick Hwang,Chung Min Shin,Jennifer A. Sherwood,김동호,Vineeth M. Vijayan,Krishna C. Josyula,Reid C. Millican,Donald Ho,Brigitta C. Brott,Vinoy Thomas,Chul Hee Choi,Sang‑Ha Oh,김동운,Ho‑Wook Jun 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

Background Capsular contracture is a critical complication of silicone implantation caused by fibrotic tissue formation from excessive foreign body responses. Various approaches have been applied, but targeting the mechanisms of capsule formation has not been completely solved. Myofibroblast differentiation through the transforming growth factor beta (TGF-β)/p-SMADs signaling is one of the key factors for capsular contracture development. In addition, biofilm formation on implants may result chronic inflammation promoting capsular fibrosis formation with subsequent contraction. To date, there have been no approaches targeting multi-facted mechanisms of capsular contracture development. Methods In this study, we developed a multi-targeting nitric oxide (NO) releasing bionanomatrix coating to reduce capsular contracture formation by targeting myofibroblast differentiation, inflammatory responses, and infections. First, we characterized the bionanomatrix coating on silicon implants by conducting rheology test, scanning electron microcsopy analysis, nanoindentation analysis, and NO release kinetics evaluation. In addition, differentiated monocyte adhesion and S. epidermidis biofilm formation on bionanomatrix coated silicone implants were evaluated in vitro. Bionanomatrix coated silicone and uncoated silicone groups were subcutaneously implanted into a mouse model for evaluation of capsular contracture development for a month. Fibrosis formation, capsule thickness, TGF-β/SMAD 2/3 signaling cascade, NO production, and inflammatory cytokine production were evaluated using histology, immunofluorescent imaging analysis, and gene and protein expression assays. Results The bionanomatrix coating maintained a uniform and smooth surface on the silicone even after mechanical stress conditions. In addition, the bionanomatrix coating showed sustained NO release for at least one month and reduction of differentiated monocyte adhesion and S. epidermidis biofilm formation on the silicone implants in vitro. In in vivo implantation studies, the bionanomatrix coated groups demonstrated significant reduction of capsule thickness surrounding the implants. This result was due to a decrease of myofibroblast differentiation and fibrous extracellular matrix production through inhibition of the TGF-β/p-SMADs signaling. Also, the bionanomatrix coated groups reduced gene expression of M1 macrophage markers and promoted M2 macrophage markers which indicated the bionanomatrix could reduce inflammation but promote healing process. Conclusions In conclusion, the bionanomatrix coating significantly reduced capsular contracture formation and promoted healing process on silicone implants by reducing myfibroblast differentiation, fibrotic tissue formation, and inflammation. Graphical Abstract A multi-targeting nitric oxide releasing bionanomatrix coating for silicone implant can reduce capsular contracture and improve healing process. The bionanomatrix coating reduces capsule thickness, α-smooth muscle actin and collagen synthesis, and myofibroblast differentiation through inhibition of TGF-β/SMADs signaling cascades in the subcutaneous mouse models for a month.