iPSC-derived mesenchymal stromal cells stimulate neovascularization less than their primary counterparts.

Aims: Mesenchymal stromal cells (MSCs) are being tested and accepted as a source for cell therapy worldwide. However, the advanced age of the patients, together with the difficulties in achieving the required cell amounts, impede autologous treatments. Reprogramming of MSCs into induced pluripotent stem cells (iPSCs), followed by re-differentiation to MSCs has emerged as a promising and safe method to facilitate the cell expansion and the removal of aging-associated characteristics.

Novel Bioreactor Design for Non-invasive Longitudinal Monitoring of Tissue-Engineered Heart Valves in 7T MRI and Ultrasound.

The development of cardiovascular implants is abundant, yet their clinical adoption remains a significant challenge in the treatment of valvular diseases. Tissue-engineered heart valves (TEHV) have emerged as a promising solution due to their remodeling capabilities, which have been extensively studied in recent years. However, ensuring reproducible production and clinical translation of TEHV requires robust longitudinal monitoring methods.

In vitro and in vivo evaluation of biohybrid tissue-engineered vascular grafts with transformative H/F MRI traceable scaffolds.

Biohybrid tissue-engineered vascular grafts (TEVGs) promise long-term durability due to their ability to adapt to hosts' needs. However, the latter calls for sensitive non-invasive imaging approaches to longitudinally monitor their functionality, integrity, and positioning. Here, we present an imaging approach comprising the labeling of non-degradable and degradable TEVGs' components for their in vitro and in vivo monitoring by hybrid H/F MRI.

The Challenge of E-Spinning Sub-Millimeter Tubular Scaffolds-A Design-of-Experiments Study for Fiber Yield Improvement.

In tissue engineering, electrospinning has gained significant interest due to its highly porous structure with an excellent surface area to volume ratio and fiber diameters that can mimic the structure of the extracellular matrix. Bioactive substances such as growth factors and drugs are easily integrated. In many applications, there is an important need for small tubular structures (I.

Multiphoton Imaging of Maturation in Tissue Engineering.

Donor cell-specific tissue-engineered (TE) implants are a promising therapy for personalized treatment of cardiovascular diseases, but current development protocols lack a stable longitudinal assessment of tissue development at subcellular resolution. As a first step toward such an assessment approach, in this study we establish a generalized labeling and imaging protocol to obtain quantified maturation parameters of TE constructs in three dimensions (3D) without the need of histological slicing, thus leaving the tissue intact. Focusing on intracellular matrix (ICM) and extracellular matrix (ECM) networks, multiphoton laser scanning microscopy (MPLSM) was used to investigate TE patches of different conditioning durations of up to 21 days.

A Dexamethasone-Loaded Polymeric Electrospun Construct as a Tubular Cardiovascular Implant.

Cardiovascular tissue engineering is providing many solutions to cardiovascular diseases. The complex disease demands necessitating tissue-engineered constructs with enhanced functionality. In this study, we are presenting the production of a dexamethasone (DEX)-loaded electrospun tubular polymeric poly(l-lactide) (PLA) or poly(d,l-lactide--glycolide) (PLGA) construct which contains iPSC-CMs (induced pluripotent stem cell cardiomyocytes), HUVSMCs (human umbilical vein smooth muscle cells), and HUVECs (human umbilical vein endothelial cells) embedded in fibrin gel.

Bio-Inspired Fiber Reinforcement for Aortic Valves: Scaffold Production Process and Characterization.

The application of tissue-engineered heart valves in the high-pressure circulatory system is still challenging. One possible solution is the development of biohybrid scaffolds with textile reinforcement to achieve improved mechanical properties. In this article, we present a manufacturing process of bio-inspired fiber reinforcement for an aortic valve scaffold.

Influence of Diameter and Cyclic Mechanical Stimulation on the Beating Frequency of Myocardial Cell-Laden Fibers.

Atrioventricular block (AVB) is a severe disease for pediatric patients. The repetitive operations needed in the case of the pacemaker implantation to maintain the electrical signal at the atrioventricular node (AVN) affect the patient's life quality. In this study, we present a method of biofabrication of multi-cell-laden cylindrical fibrin-based fibers that can restore the electrical signal at the AVN.

Self-crosslinked polyvinyl alcohol/cellulose nanofibril cryogels loaded with synthesized aminophosphonates as antimicrobial wound dressings.

Microbial infection is the most common obstacle in the wound healing process, leading to wound healing impairment and complications and ultimately increasing morbidity and mortality. Due to the rising number of pathogens evolving resistance to the existing antibiotics used for wound care, alternative approaches are urgently required. In this study, α-aminophosphonate derivatives as antimicrobial agents were synthesized and incorporated into self-crosslinked tri-component cryogels composed of fully hydrolyzed polyvinyl alcohol (PVA-F), partially hydrolyzed polyvinyl alcohol (PVA-P), and cellulose nanofibrils (CNFs).

Biomechanical evaluation of a novel biomimetic artificial intervertebral disc in canine cervical cadaveric spines.

Background Context: Cervical disc replacement (CDR) aims to restore motion of the treated level to reduce the risk of adjacent segment disease (ASD) compared with spinal fusion. However, first-generation articulating devices are unable to mimic the complex deformation kinematics of a natural disc. Thus, a biomimetic artificial intervertebral CDR (bioAID), containing a hydroxyethylmethacrylate (HEMA)-sodium methacrylate (NaMA) hydrogel core representing the nucleus pulposus, an ultra-high-molecular-weight-polyethylene fiber jacket as annulus fibrosus, and titanium endplates with pins for primary mechanical fixation, was developed.

Transformative Materials to Create 3D Functional Human Tissue Models In Vitro in a Reproducible Manner.

Recreating human tissues and organs in the petri dish to establish models as tools in biomedical sciences has gained momentum. These models can provide insight into mechanisms of human physiology, disease onset, and progression, and improve drug target validation, as well as the development of new medical therapeutics. Transformative materials play an important role in this evolution, as they can be programmed to direct cell behavior and fate by controlling the activity of bioactive molecules and material properties.

Lifelike Transformative Materials for Biohybrid Implants: Inspired by Nature, Driven by Technology.

Today's living world is enriched with a myriad of natural biological designs, shaped by billions of years of evolution. Unraveling the construction rules of living organisms offers the potential to create new materials and systems for biomedicine. From the close examination of living organisms, several concepts emerge: hierarchy, pattern repetition, adaptation, and irreducible complexity.

Mechanical characterization of a novel biomimetic artificial disc for the cervical spine.

A novel biomimetic artificial intervertebral disc (bioAID) replacement implant has been developed containing a swelling hydrogel representing the nucleus pulposus, a tensile strong fiber jacket as annulus fibrosus and titanium endplates with pins to primarily secure the device between the vertebral bodies. In this study, the design safety of this novel implant was evaluated based on several biomechanical parameters, namely compressive strength, shear-compressive strength, risk of subsidence and device expulsion as well as identifying the diurnal creep-recovery characteristics of the device. The bioAID remained intact up to 1 kN under static axial compression and only 0.

Bioglues Based on an Elastin-Like Recombinamer: Effect of Tannic Acid as an Additive on Tissue Adhesion and Cytocompatibility.

More than 260 million surgical procedures are performed worldwide each year. Although sutures and staples are widely used to reconnect tissues, they can cause further damage and increase the risk of infection. Bioadhesives have been proposed as an alternative to reconnect tissues.

Influence of Aerosolization on Endothelial Cells for Efficient Cell Deposition in Biohybrid and Regenerative Applications.

The endothelialization of gas exchange membranes can increase the hemocompatibility of extracorporeal membrane oxygenators and thus become a long-term lung replacement option. Cell seeding on large or uneven surfaces of oxygenator membranes is challenging, with cell aerosolization being a possible solution. In this study, we evaluated the endothelial cell aerosolization for biohybrid lung application.

Long-Term Degradation Assessment of a Polyurethane-Based Surgical Adhesive-Assessment and Critical Consideration of Preclinical In Vitro and In Vivo Testing.

Tissue adhesives constitute a great possibility to improve conventional wound closure. In contrast to sutures, they enable nearly immediate hemostasis and can prevent fluid or air leaks. In the present study, a poly(ester)urethane-based adhesive was investigated which already proved to be suitable for different indications, such as reinforcing vascular anastomosis and sealing liver tissue.

Thermoresponsive nanofibers loaded with antimicrobial α-aminophosphonate-o/w emulsion supported by cellulose nanocrystals for smart wound care patches.

Long-term topical application of antibiotics on wounds has led to the emergence of drug-resistant bacterial infections. Antibiotic incorporation into the wound dressing requires enormous advancement of the field to ensure that the needed dose is released when the infection arises. This study synthesized a series of antimicrobial α-aminophosphonate derivatives, and the most effective compound was incorporated into thermoresponsive wound dressing patches.

Influence of polypropylene mesh degradation on tissue inflammatory reaction.

Polypropylene degradation in vivo appears as mesh surface cracking and peeling. This aging process of the mesh, resulting in the lack of bio-stability, contradicts the requirement of biocompatibility. However, to date, it is still not clearly established how much this mesh degradation influences the local tissue response with subsequent clinical consequences.

Bioprinting-Associated Shear Stress and Hydrostatic Pressure Affect the Angiogenic Potential of Human Umbilical Vein Endothelial Cells.

Bioprinting-associated shear stress and hydrostatic pressure can negatively affect the functionality of dispensed cells. We hypothesized that these mechanical stimuli can potentially affect the angiogenic potential of human umbilical vein endothelial cells (HUVECs). A numerical simulation model was used to calculate the shear stress during microvalve-based droplet ejection.

Effervescent Atomizer as Novel Cell Spray Technology to Decrease the Gas-to-Liquid Ratio.

Cell spraying has become a feasible application method for cell therapy and tissue engineering approaches. Different devices have been used with varying success. Often, twin-fluid atomizers are used, which require a high gas velocity for optimal aerosolization characteristics.

Biohybrid elastin-like venous valve with potential for tissue engineering.

Chronic venous insufficiency (CVI) is a leading vascular disease whose clinical manifestations include varicose veins, edemas, venous ulcers, and venous hypertension, among others. Therapies targeting this medical issue are scarce, and so far, no single venous valve prosthesis is clinically available. Herein, we have designed a bi-leaflet transcatheter venous valve that consists of (i) elastin-like recombinamers, (ii) a textile mesh reinforcement, and (iii) a bioabsorbable magnesium stent structure.

From In Vitro to Perioperative Vascular Tissue Engineering: Shortening Production Time by Traceable Textile-Reinforcement.

Background: The production of tissue-engineered vascular graft (TEVG) usually involves a prolonged bioreactor cultivation period of up to several weeks to achieve maturation of extracellular matrix and sufficient mechanical strength. Therefore, we aimed to substantially shorten this conditioning time by combining a TEVG textile scaffold with a recently developed copolymer reinforced fibrin gel as a cell carrier. We further implemented our grafts with magnetic resonance imaging (MRI) contrast agents to allow the in-vitro monitoring of the TEVG's remodeling process.

Towards technically controlled bioreactor maturation of tissue-engineered heart valves.

Bioreactors are important tools for the pre-conditioning of tissue-engineered heart valves. The current state of the art mostly provides for timed, physical and biochemical stimulation in the bioreactor systems according to standard protocols (SOP). However, this does not meet to the individual biological variability of living tissue-engineered constructs.