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We used the radial artery as a second target conduit for coronary artery bypass grafting since 1971. However, randomized clinical studies have demonstrated differences in clinical outcomes between the radial artery and other grafts because these trials are underpowered. As we proceed toward 50 years of experience with radial artery grafting, we examined the literature to define the best second-best target vessel for coronary artery bypass grafting. The literature was reviewed with emphasis, and a large number of randomized controlled trials, propensity-matched observational series, and meta-analyses were identified with a large patient population who received arterial conduit and saphenous vein grafts. The radial artery has been shown to be effective and safe when used as a second target conduit for coronary artery bypass grafting. Results and patency rates were superior to those for saphenous vein grafting. It has also been shown that the radial artery is a safe and effective graft as a third conduit into the territory of the artery right coronary artery. However, there is little evidence based on a few comparable series limiting the use of the gastroepiploic artery. In its fifth decade of use, we can finally deduced that the aorto-to-coronary radial bypass graft is the conduit of choice for coronary operations after the left internal thoracic artery to the left anterior descending artery.

Aortic stenosis is a disease that is increasing in prevalence and manifests as decreased cardiac output, which if left untreated can result in heart failure and ultimately death. It is primarily a disease of the elderly who often have multiple comorbidities. The advent of transcatheter aortic valve therapies has changed the way we treat these conditions. However, long-term results of these therapies remain uncertain. Recently, there has been an increasing number of studies examining the role of both surgical aortic valve replacement and transcatheter aortic valve replacement. We therefore performed a systematic review using Ovid MEDLINE, Ovid Embase, and the Cochrane Library. Two investigators searched papers published between January 1, 2007, and to date using the following terms: “aortic valve stenosis,” “aortic valve operation,” and “transcatheter aortic valve therapy.” Both strategies in aortic stenosis treatment highlighted specific indications alongside the pitfalls such as structural valve degeneration and valve thrombosis which have a bearing on clinical outcomes. We propose some recommendations to help clinicians in the decision-making process as technological improvements make both surgical and transcatheter therapies viable options for patients with aortic stenosis. Finally, we assess the role of finite element analysis in patient selection for aortic valve replacement. THVT and AVR-S are both useful tools in the armamentarium against aortic stenosis. The decision between the two treatment strategies should be best guided by a strong robust evidence base, ideally with a long-term follow-up. This is best performed by the heart team with the patient as the center of the discussion.

The Ross procedure has long been seen as an optimal operation for a select few. The detractors of it highlight the issue of an additional harvesting of the pulmonary artery, subjecting the native PA to systemic pressures and the need for reintervention as reasons to avoid it. However, the PA is a living tissue and capable of adapting and remodeling to growth. We therefore review the current evidence available to discuss the indications, contraindications, harvesting techniques, and modifications in a state-of-the-art narrative review of the PA as an aortic conduit. Due to the lack of substantial well-designed randomized controlled trials (RCTs), we also highlight the areas of need to reiterate the importance of the Ross procedure as part of the surgical armamentarium.

Major target for prosthetic constructs of bone is the ability to elicit osteoinduction, osteoconduction and osteointegration. Promising constructs are represented by composite scaffolds made of biodegradable natural polysaccharides endowed with biocompatibility and mechanical properties. Alginate is a good candidate when its limits - weak mechanical properties and lack of cellular interactions - are overcome by reinforcing with inorganic components. In the present study an innovative strategy was developed to obtain three-dimensional scaffolds made up of alginate (Alg) and Hydroxyapatite (HAp). Scanning electron microscopy (SEM) observations, confocal laser scanning microscopy (CLSM) and micro-computed tomography (µ-CT) analysis of the scaffolds showed an optimal interconnected porous structure with pore sizes ranging between 100 µm and 300 µm and over 88% porosity. Proliferation assay and SEM observations demonstrated that human osteosarcoma cell lines seeded onto the scaffolds were able to proliferate, maintain osteoblast-like phenotype and massively colonize the structure. Overall, these combined results indicate that the novel alginate based composites efficiently support the adhesion and proliferation of cells showing at the same time adequate structural and physical-chemical properties for being used as scaffolds in bone tissue engineering strategies. Biocompatibility and bioactivity of the scaffolds were tested both in vitro and in vivo.

Skin absorption and toxicity on keratinocytes of cobalt oxide nanoparticles (Co3O4NPs) have been investigated. Co3O4NPs are commonly used in industrial products and biomedicine. There is evidence that these nanoparticles can cause membrane damage and genotoxicity in vitro, but no data are available on their skin absorption and cytotoxicity on keratinocytes. Two independent 24 h in vitro experiments were performed using Franz diffusion cells, using intact (experiment 1) and needle-abraded human skin (experiment 2). Co3O4NPs at a concentration of 1000 mg/L in physiological solution were used as donor phase. Cobalt content was evaluated by Inductively Coupled–Mass Spectroscopy. Co permeation through the skin was demonstrated after 24 h only when damaged skin protocol was used (57 ± 38 ng·cm−2), while no significant differences were shown between blank cells (0.92 ± 0.03 ng cm−2) and those with intact skin (1.08 ± 0.20 ng·cm−2). To further investigate Co3O4NPs toxicity, human-derived HaCaT keratinocytes were exposed to Co3O4NPs and cytotoxicity evaluated by MTT, Alamarblue® and propidium iodide (PI) uptake assays. The results indicate that a long exposure time (i.e., seven days) was necessary to induce a concentration-dependent cell viability reduction (EC50 values: 1.3 × 10−4 M, 95% CL = 0.8–1.9 × 10−4 M, MTT essay, 3.7 × 10−5 M, 95% CI = 2.2–6.1 × 10−5 M, AlamarBlue® assay) that seems to be associated to necrotic events (EC50 value: 1.3 × 10−4 M, 95% CL = 0.9–1.9 × 10−4 M, PI assay). This study demonstrated that Co3O4NPs can penetrate only damaged skin and is cytotoxic for HaCat cells after long term exposure.

In this study nano-composite scaffolds to be used as bone grafts have been endowed with antibacterial properties owing to the presence of silver nanoparticles. The alginate/hydroxyapatite composite scaffolds were prepared by internal gelation followed by a freeze-drying procedure to obtain a porous structure. The nanoparticles were prepared in presence of a lactose modified-chitosan and this colloidal solution was adsorbed on the scaffolds by exploiting electrostatic interactions. The adsorption and release of the silver from the composite scaffold was measured by ICP-AES and spectrofluorimetry measurements. Micro-computed tomography analysis of the scaffolds showed a homogeneous porous structure with average pore sizes of 341.5 μm and porosity of 80 %. In vitro biological tests (MTS and killing kinetics assays) demonstrated that silver does not affect the ability of the scaffolds to promote osteoblasts proliferation and that at the same time it exerts a strong bactericidal effect against both Gram+ and Gram- bacterial strains. Overall, the combined results indicate that these biocompatible antimicrobial scaffolds possess ideal characteristics for tissue engineering applications.

Alginate/hydroxyapatite composite scaffolds were developed using a novel production design. Hydroxyapatite (HAp) was incorporated into an alginate solution and internal gelling was induced by addition of slowly acid hydrolyzing d-gluconic acid delta-lactone (GDL) for the direct release of calcium ions from HAp. Hydrogels were then freeze-casted to produce a three-dimensional isotropic porous network. Scanning electron microscopy (SEM) observations, confocal laser scanning microscopy (CLSM) and microcomputed tomography (micro-CT) analysis of the scaffolds showed an optimal interconnected porous structure with pore sizes ranging between 100 and 300 microm and over 88% porosity. Proliferation assay and SEM observations demonstrated that human osteosarcoma cell lines were able to proliferate, maintain osteoblast-like phenotype and massively colonize the scaffold structure. Overall, these combined results indicate that the novel alginate based composites efficiently support the adhesion and proliferation of cells showing at the same time adequate structural and physical-chemical properties for being used as scaffolds in bone tissue engineering strategies.

Bisphenol A glycidylmethacrylate (BisGMA)/triethyleneglycol dimethacrylate (TEGDMA) thermosets and composites are well-known examples of biomaterials for dental applications that are receiving growing interest for orthopedic applications. While mechanical bulk properties are guaranteed by the presence of reinforcing fibers, in vitro and in vivo performances of these materials are ultimately driven by their ability to establish proper interactions between their surface and the surrounding tissues. Hence, the development of novel chemical processes enabling the introduction of bioactive molecules on the surface of these methacrylate-based thermosets is of particular interest. In the present work, we have devised a chemical strategy to expose carboxylic groups on the surface of the BisGMA/TEGDMA thermoset. The presence of negative charges was confirmed by Fourier transform infrared-attenuated total reflectance and by UV-vis spectrophotometry. Bulk mechanical properties and surface morphology of the thermoset were only slightly affected upon chemical functionalization. The activated material was further refined by the deposition of a lactose-modified chitosan (chitlac) driven by strong electrostatic interactions. The presence of the bioactive polysaccharide was confirmed by fluorescence spectroscopy and by confocal laser scanning microscopy measurements. Scratch tests were performed to evaluate the mechanical behavior of the coating. Finally, in vitro tests revealed that the presence of chitlac led to a slight enhancement of cell proliferation with respect to the unmodified BisGMA/TEGDMA thermoset. This effect was more pronounced when chitlac decorated with an arginine-glycine-aspartic acid (RGD) peptide was used in the preparation of the coating. In the latter case, the in vitro performance of the coated BisGMA/TEGDMA thermoset became comparable with that of clinically used roughened titanium.