Bioresorbable Vascular Scaffolds - Are We Facing a Time of Crisis or One of Breakthrough?

A Nature-Derived, Hetero-Structured, Pro-Healing Bioadhesive Patch for High-Performance Sealing of Wet Tissues

Tissue adhesives are promising alternatives to sutures and staples to achieve wound closure and hemostasis. However, they often do not work well on tissues that are soaked in blood or other biological fluids, and organs that are typically exposed to a variety of harsh environments such as different pH values, nonhomogeneous distortions, continuous expansions and contractions, or high pressures. In this study, a nature-derived multilayered hetero-bioadhesive patch (skin secretion of Andrias davidianus (SSAD)-Patch) based on hydrophilic/hydrophobic pro-healing bioadhesives derived from the SSAD is developed, which is designed to form pressure-triggered strong adhesion with wet tissues. The SSAD-Patch is successfully applied for the sealing and healing of tissue defects within 10 s in diverse extreme injury scenarios in vivo including rat stomach perforation, small intestine perforation, fetal membrane defect, porcine carotid artery incision, and lung lobe laceration. The findings reveal a promising new type of self-adhesive regenerative SSAD-Patch, which is potentially adaptable to broad applications (under different pH values and air or liquid pressures) in sutureless wound sealing and healing.

Effects of extract solution from magnesium alloys supplemented with different compositions of rare earth elements on in vitro epithelial and osteoblast progenitor cells

Background: Magnesium alloys (Mg-alloys) have gained significant attention in recent years as a potential bioactive material for clinical applications. The incorporation of rare earth elements (REEs) into Mg-alloys has been of particular interest due to their potential to improve both mechanical and biological properties. Although there are diverse results in terms of cytotoxicity and biological effects of REEs, investigating the physiological benefits of Mg-alloys supplemented with REEs will help in the transition from theoretical to practical applications. Methods: In this study, two culture systems were used to evaluate the effects of Mg-alloys containing gadolinium (Gd), dysprosium (Dy), and yttrium (Y): human umbilical vein endothelial cells (HUVEC) and mouse osteoblastic progenitor cells (MC3T3-E1). Different compositions of Mg-alloys were assessed, and the effects of the extract solution on cell proliferation, viability, and specific cell functions were analyzed. Results: Within the range of weight percentages tested, the Mg-REE alloys did not exhibit any significant negative impacts on either cell line. Interestingly, moderate compositions (Mg-1.5Gd-1.5Dy-0.825Y-0.5Zr and Mg-2Gd-2Dy-1.1Y-0.5Zr) demonstrated a tendency to enhance osteoblastic activity and promote the vascularization process in both HUVEC and MC3T3-E1 cell lines. Discussion: The results of this study provide valuable insights into the potential benefits of REE-supplemented Mg-alloys for clinical applications. The observed enhancement in osteoblastic activity and promotion of vascularization processes suggest that optimizing the compositions of REEs in Mg-alloys could lead to the development of novel, more effective bioactive materials. Further investigations are required to understand the underlying mechanisms and to refine the alloy compositions for improved biocompatibility and performance in clinical settings.

Systems, Properties, Surface Modification and Applications of Biodegradable Magnesium-Based Alloys: A Review

In recent years, biodegradable magnesium (Mg) alloys have attracted the attention of many researchers due to their mechanical properties, excellent biocompatibility and unique biodegradability. Many Mg alloy implants have been successfully applied in clinical medicine, and they are considered to be promising biological materials. In this article, we review the latest research progress in biodegradable Mg alloys, including research on high-performance Mg alloys, bioactive coatings and actual or potential clinical applications of Mg alloys. Finally, we review the research and development direction of biodegradable Mg alloys. This article has a guiding significance for future development and application of high-performance biodegradable Mg alloys, promoting the future advancement of the magnesium alloy research field, especially in biomedicine.

Crimping-induced structural gradients explain the lasting strength of poly l-lactide bioresorbable vascular scaffolds during hydrolysis

Biodegradable polymers open the way to treatment of heart disease using transient implants (bioresorbable vascular scaffolds, BVSs) that overcome the most serious complication associated with permanent metal stents-late stent thrombosis. Here, we address the long-standing paradox that the clinically approved BVS maintains its radial strength even after 9 mo of hydrolysis, which induces a ∼40% decrease in the poly l-lactide molecular weight (Mn). X-ray microdiffraction evidence of nonuniform hydrolysis in the scaffold reveals that regions subjected to tensile stress during crimping develop a microstructure that provides strength and resists hydrolysis. These beneficial morphological changes occur where they are needed most-where stress is localized when a radial load is placed on the scaffold. We hypothesize that the observed decrease in Mn reflects the majority of the material, which is undeformed during crimping. Thus, the global measures of degradation may be decoupled from the localized, degradation-resistant regions that confer the ability to support the artery for the first several months after implantation.

Two-year longitudinal evaluation of a second-generation thin-strut sirolimus-eluting bioresorbable coronary scaffold with hybrid cell design in porcine coronary arteries

BACKGROUND

The first commercially available bioresorbable scaffold (BRS) had a strut thickness of 156 microns. As such, it had the potential for delivery challenges and higher thrombogenicity. The aim herein, is to evaluate biomechanical performance, pharmacokinetics and vascular healing of a novel thin strut (100 μm) sirolimus eluting BRS (MeRes-100, Meril Life Sciences, Gujarat, India) against the once clinically used BRS (Absorb BVS, Abbott, Santa Clara, CA) in porcine coronary arteries.

METHODS

Following device implantation, angiographic and optical coherence tomography (OCT) evaluation were performed at 45, 90, 180 days, 1 year and 2 years. Histological evaluation was per-formed at 30, 90 and 180 days.

RESULTS

At 2 years, both lumen (MeRes-100 7.07 ± 1.82 mm² vs. Absorb BVS 7.57 ± 1.39 mm2, p = NS) and scaffold areas (MeRes-100 9.73 ± 1.80 mm² vs. Absorb BVS 9.67 ± 1.25 mm², p = NS) were comparable between tested and control scaffolds. Also, the late lumen area gain at 2 years was similar in both groups tested (MeRes-100 1.03 ± 1.98 mm² vs. Absorb BVS 0.85 ± 1.56 mm², p = NS). Histologic examination up to 6 months showed comparable healing and inflammation profiles for both devices.

CONCLUSIONS

The novel sirolimus-eluting BRS with thinner struts and hybrid cell design showed similar biomechanical durability and equivalent inhibition of neointimal proliferation when compared to the first-ever Absorb BVS up to 2 years in normal porcine coronary arteries.