Artificial Organs Research Articles

Bio-inspired circular soft actuators for simulating defecation process of human rectum.

Soft robots have found extensive applications in the medical field, particularly in rehabilitation exercises, assisted grasping, and artificial organs. Despite significant advancements in simulating various components of the digestive system, the rectum has been largely neglected due to societal stigma. This study seeks to address this gap by developing soft circular muscle actuators (CMAs) and rectum models to replicate the defecation process. Using soft materials, both the rectum and the actuators were fabricated to enable seamless integration and attachment. We designed, fabricated, and tested three types of CMAs and compared them to the simulated results. A pneumatic system was employed to control the actuators, and simulated stool was synthesized using sodium alginate and calcium chloride. Experimental results indicated that the third type of actuator exhibited superior performance in pressure generation, enabling the area contraction to reach a maximum value of 1. The successful simulation of the defecation process highlights the potential of these soft actuators in biomedical applications, providing a foundation for further research and development in the field of soft robotics.

The Role of the Pancreatic Extracellular Matrix as a Tissue Engineering Support for the Bioartificial Pancreas.

Type 1 diabetes mellitus (T1DM) is a chronic condition primarily managed with insulin replacement, leading to significant treatment costs. Complications include vasculopathy, cardiovascular diseases, nephropathy, neuropathy, and reticulopathy. Pancreatic islet transplantation is an option but its success does not depend solely on adequate vascularization. The main limitations to clinical islet transplantation are the scarcity of human pancreas, the need for immunosuppression, and the inadequacy of the islet isolation process. Despite extensive research, T1DM remains a major global health issue. In 2015, diabetes affected approximately 415 million people, with projected expenditures of USD 1.7 trillion by 2030. Pancreas transplantation faces challenges due to limited organ availability and complex vascularization. T1DM is caused by the autoimmune destruction of insulin-producing pancreatic cells. Advances in biomaterials, particularly the extracellular matrix (ECM), show promise in tissue reconstruction and transplantation, offering structural and regulatory functions critical for cell migration, differentiation, and adhesion. Tissue engineering aims to create bioartificial pancreases integrating insulin-producing cells and suitable frameworks. This involves decellularization and recellularization techniques to develop biological scaffolds. The challenges include replicating the pancreas's intricate architecture and maintaining cell viability and functionality. Emerging technologies, such as 3D printing and advanced biomaterials, have shown potential in constructing bioartificial organs. ECM components, including collagens and glycoproteins, play essential roles in cell adhesion, migration, and differentiation. Clinical applications focus on developing functional scaffolds for transplantation, with ongoing research addressing immunological responses and long-term efficacy. Pancreatic bioengineering represents a promising avenue for T1DM treatment, requiring further research to ensure successful implementation.

Tough gelatine hydrogels reinforced with silk fibroin nanofiber

Gelatine hydrogels exhibit potential as biomaterials such as wound-healing materials, artificial organs, scaffolds for cell culture and drug delivery systems because of their good biocompatibility. However, their practical applications are limited by their poor mechanical properties and high degradability. In this study, mechanically fibrillated silk fibroin (fibroin nanofibers; FNF) was used to reinforce gelatine hydrogels. The resulting gelatine hydrogels with FNF exhibited enhanced toughness compared to those reinforced with conventional aqueous regenerated fibroin (RF), which were prepared by treatment with a highly concentrated LiBr solvent or a neat gelatine hydrogel while retaining their softness. The average pore size of the gelatine hydrogel was 2.2 μm, while the gelatine hydrogel containing 25 % FNF expanded to 6.7 μm. A web-like network was formed between the pores. The addition of FNF increased the relative β-sheet contents in the hydrogels to 60.3 %, suggesting that this may have caused structural changes such as increased crystallinity for gelatine-derived proteins. Furthermore, the addition of FNF inhibited the rapid enzymatic degradation of gelatine hydrogels. FNF, which can be easily prepared in water, is a safe material for both the environment and living organisms and holds promise as a biomaterial in the future.

Specific features of anesthesia management in a patient with a transplanted heart

Background. The number of heart transplant patients makes 1 per 100,000 in the Russian Federation, 1.2 per 100,000 population in the Tambov Region. The medical community is poorly informed about the specific features of managing such patients during non-cardiac surgical interventions. The article presents a case report of the management of a patient with a transplanted heart undergoing surgery for acute appendicitis. Preoperative preparation, anesthesia management, surgery, and postoperative care and rehabilitation were provided taking into account the presence of a transplanted heart in the patient, according to the Guidelines developed by the experts of the V.I. Shumakov Federal Research Center of Transplantology and Artificial Organs where the heart transplant had been performed to the patient, and standard clinical recommendations.Case Report. An 18-year-old patient diagnosed with acute phlegmonous appendicitis with a heart transplanted in 2021 for dilated cardiomyopathy underwent laparoscopic appendectomy 3 years after heart transplantation. Anesthesia was provided taking into account the presence of a denervated donor heart, a high risk of myocardial ischemia and heart ailure (low cardiac output syndrome), and the need for a timely correction of hypovolemia and hypotension. Anesthesia management was a general combined multicomponent anesthesia.Conclusion. This clinical case has shown the possibility of providing medical care to a patient with a transplanted heart at a modern level in an urban multidisciplinary hospital. Non-cardiac surgery was performed in accordance with recommendations of specialists of V.I. Shumakov Federal Research Center of Transplantology and Artificial Organs and clinical recommendations in order to achieve optimal results and the fastest possible rehabilitation in the postoperative period.

3D bioprinting technology and equipment based on microvalve control.

3D bioprinting technology is widely used in biomedical fields such as tissue regeneration and constructing pathological model. The prevailing printing technique is extrusion-based bioprinting. In this printing method, the bioink needs to meet both printability and functionality, which are often conflicting requirements. Therefore, this study has developed an innovative microvalve-based equipment, incorporating components such as pressure control, a three-dimensional motion platform, and microvalve. Here, we present a droplet-based method for constructing complex three-dimensional structures. By leveraging the rapid switching characteristics of the microvalve, this equipment can achieve precise printing of bio-materials with viscosities as low as 10mPa·s, significantly expanding the biofabrication window for bioinks. This technology is of great significance for 3D bioprinting in tissue engineering and lays a solid foundation for the construction of complex artificial organ tissues.

Dr. Willem Kolff: The Father of the Artificial Kidney.

Dr. Willem J. Kolff(February 14, 1911-February 11, 2009) is widely considered the father of dialysis. In addition, his innovations also included the artificial heart and lung, which earned him the title "the Father of Artificial Organs". In due course, his artificial kidney evolved into modern dialysis, a procedure that filters and purifies blood using an extracorporeal circuit, now a life-sustaining treatment for patients with end-stage kidney failure. Furthermore, his membrane oxygenator, which provided a method to add oxygen to blood as it passed through a machine, is still used in heart-lung machines during open-heart surgery. He is also known for his work in developing the artificial heart (although it now carries the name of his student, Dr. Robert Jarvik), which was used in subsequent designs, as a bridge to heart transplantation.Thanks to his work on the artificial kidney, millions of patients worldwide have benefited from life-sustaining hemodialysis. It can also be argued that Dr. Kolff's introduction of dialysis in 1943 marks the dawn of modern nephrology.

A polymer-like ultrahigh-strength metal alloy

Futuristic technologies such as morphing aircrafts and super-strong artificial muscles depend on metal alloys being as strong as ultrahigh-strength steel yet as flexible as a polymer1–3. However, achieving such ‘strong yet flexible’ alloys has proven challenging4–9 because of the inevitable trade-off between strength and flexibility5,8,10. Here we report a Ti–50.8 at.% Ni strain glass alloy showing a combination of ultrahigh yield strength of σy ≈ 1.8 GPa and polymer-like ultralow elastic modulus of E ≈ 10.5 GPa, together with super-large rubber-like elastic strain of approximately 8%. As a result, it possesses a high flexibility figure of merit of σy/E ≈ 0.17 compared with existing structural materials. In addition, it can maintain such properties over a wide temperature range of −80 °C to +80 °C and demonstrates excellent fatigue resistance at high strain. The alloy was fabricated by a simple three-step thermomechanical treatment that is scalable to industrial lines, which leads not only to ultrahigh strength because of deformation strengthening, but also to ultralow modulus by the formation of a unique ‘dual-seed strain glass’ microstructure, composed of a strain glass matrix embedded with a small number of aligned R and B19′ martensite ‘seeds’. In situ X-ray diffractometry shows that the polymer-like deformation behaviour of the alloy originates from a nucleation-free reversible transition between strain glass and R and B19′ martensite during loading and unloading. This exotic alloy with the potential for mass producibility may open a new horizon for many futuristic technologies, such as morphing aerospace vehicles, superman-type artificial muscles and artificial organs.

Formation of interfaces responsive and adaptive to environment via the sol-gel method

Smart devices, such as soft robots, artificial organs, and soft actuators, require materials that adapt their morphologies and properties in response to their environment. These materials can be obtained through the composition of different types of materials that exhibit different responses to environmental stimuli, arranged in a rational spatial configuration. We achieved unique responsive materials by forming interfaces and surfaces of appropriate materials using the sol–gel method. In recent decades, we have proposed the use of wrinkles and nano-brushes on sol–gel-derived materials for various sophisticated applications, such as micropattern fabrication, wettability control, and linear actuators for size-selective transportation. This account introduces environment-responsive materials with rational interfaces via the sol–gel method, particularly those characterized by surface morphology.Graphical Materials with unique environmental responsiveness such as micropattern fabrication, wettability control, and linear actuating can be achieved by forming interfaces and surfaces using the sol–gel method.

High-resolution 3D spatial distribution of complex microbial colonies revealed by mass spectrometry imaging

IntroductionBacterial living states and the distribution of microbial colony signaling molecules are widely studied using mass spectrometry imaging (MSI). However, current approaches often treat 3D colonies as flat 2D disks, inadvertently omitting valuable details. The challenge of achieving 3D MSI in biofilms persists due to the unique properties of microbial samples. ObjectivesThe study aimed to develop a new biofilm sample preparation method that can realize high-resolution 3D MSI of bacterial colonies to reveal the spatial organization of bacterial colonies. MethodsThis article introduces the moisture-assisted cryo-section (MACS) method, enabling embedding-free sectioning parallel to the growth plane. The MACS method secures intact sections by controlling ambient humidity and slice thickness, preventing molecular delocalization. ResultsCombined with matrix-assisted laser desorption ionization mass spectrometry (MALDI)-MSI, the MACS method provides high-resolution insights into endogenic and exogenous molecule distributions in Pseudomonas aeruginosa (P. aeruginosa) biofilms, including isomeric pairs. Moreover, analyzed colonies are revived into 3D models, vividly depicting molecular distribution from inner to outer layers. Additionally, we investigated metabolite spatiotemporal dynamics in multiple colonies, observing changes over time and distinct patterns in single versus merged colonies. These findings shed light on the repel-merge process for multi-colony formation. Furthermore, our study monitored chemical responses inside biofilms after antibiotic treatment, showing increased antibiotic levels in the outer biofilm layer over time while maintaining low levels in the inner region. Moreover, the MACS method demonstrated its universality and applicability to other bacterial strains. ConclusionThese results unveil complex cell activities within biofilm colonies, offering insights into microbe communities. The MACS method is universally applicable to loosely packed microorganism colonies, overcoming the limitations of previously reported MSI methods. It has great potential for studying bacterial-infected cancer tissues and artificial organs, making it a valuable tool in microbiological research.

Optimising Bioprinting Nozzles through Computational Modelling and Design of Experiments.

3D bioprinting is a promising technique for creating artificial tissues and organs. One of the main challenges of bioprinting is cell damage, due to high pressures and tensions. During the biofabrication process, extrusion bioprinting usually results in low cell viability, typically ranging from 40% to 80%, although better printing performance with higher cell viability can be achieved by optimising the experimental design and operating conditions, with nozzle geometry being a key factor. This article presents a review of studies that have used computational fluid dynamics (CFD) to optimise nozzle geometry. They show that the optimal ranges for diameter and length are 0.2 mm to 1 mm and 8 mm to 10 mm, respectively. In addition, it is recommended that the nozzle should have an internal angle of 20 to 30 degrees, an internal coating of ethylenediaminetetraacetic acid (EDTA), and a shear stress of less than 10 kPa. In addition, a design of experiments technique to obtain an optimal 3D bioprinting configuration for a bioink is also presented. This experimental design would identify bioprinting conditions that minimise cell damage and improve the viability of the printed cells.

Single/Multi-Network Conductive Hydrogels-A Review.

Hydrogels made from conductive organic materials have gained significant interest in recent years due to their wide range of uses, such as electrical conductors, freezing resistors, biosensors, actuators, biomedical engineering materials, drug carrier, artificial organs, flexible electronics, battery solar cells, soft robotics, and self-healers. Nevertheless, the insufficient level of effectiveness in electroconductive hydrogels serves as a driving force for researchers to intensify their endeavors in this domain. This article provides a concise overview of the recent advancements in creating self-healing single- or multi-network (double or triple) conductive hydrogels (CHs) using a range of natural and synthetic polymers and monomers. We deliberated on the efficacy, benefits, and drawbacks of several conductive hydrogels. This paper emphasizes the use of natural polymers and innovative 3D printing CHs-based technology to create self-healing conductive gels for flexible electronics. In conclusion, advantages and disadvantages have been noted, and some potential opportunities for self-healing single- or multi-network hydrogels have been proposed.

Liver bioprinting within a novel support medium with functionalized spheroids, hepatic vein structures, and enhanced post-transplantation vascularization

Cell-laden bioprinting is a promising biofabrication strategy for regenerating bioactive transplants to address organ donor shortages. However, there has been little success in reproducing transplantable artificial organs with multiple distinctive cell types and physiologically relevant architecture. In this study, an omnidirectional printing embedded network (OPEN) is presented as a support medium for embedded 3D printing. The medium is state-of-the-art due to its one-step preparation, fast removal, and versatile ink compatibility. To test the feasibility of OPEN, exceptional primary mouse hepatocytes (PMHs) and endothelial cell line-C166, were used to print hepatospheroid-encapsulated-artificial livers (HEALs) with vein structures following predesigned anatomy-based printing paths in OPEN. PMHs self-organized into hepatocyte spheroids within the ink matrix, whereas the entire cross-linked structure remained intact for a minimum of ten days of cultivation. Cultivated HEALs maintained mature hepatic functions and marker gene expression at a higher level than conventional 2D and 3D conditions in vitro. HEALs with C166-laden vein structures promoted endogenous neovascularization in vivo compared with hepatospheroid-only liver prints within two weeks of transplantation. Collectively, the proposed platform enables the manufacture of bioactive tissues or organs resembling anatomical architecture, and has broad implications for liver function replacement in clinical applications.

"Kyushu-style" collaboration between the implantable ventricular assist device implantation and management centers: a republication of the article published in Japanese journal of artificial organs.

Collaboration between the implantation centers, management centers, and regional core hospitals is a key factor in securing long-term implantable ventricular assist device (VAD) management. In Kyushu, a management system for patients with implantable VADs has been established at the prefectural and regional levels. Presently, six implantable VAD implantation centers and seven management centers exists in the eight prefectures of Kyushu and Okinawa, with at least one specialized VAD centers in each prefecture. This collaborative management system allows patients with VADs to receive seamless treatment based on the same management concept wherever they live. In fact, approximately half of the present outpatients treated at our center reside outside the prefecture and are managed in collaboration with management centers and regional core hospitals. Among our patients, there were no significant differences in survival or rehospitalization-free rates between patients with VADs in and out of the prefecture, suggesting that the place of residence did not affect the outcome. With the increase in the number of patients with VADs and the diversification of patients, patient management has become more complex. Mutual collaboration between the implantation centers, management centers, and regional core hospitals, is essential to improve the quality of VAD management. This review was created based on a translation of the Japanese review written in the Japanese Journal of Artificial Organs in 2023 (Vol. 52, No. 1, pp. 85-88), with some modifications.

Current trends in additive manufacturing of selective laser melting for biomedical implant applications

Additive manufacturing (AM) has obtained great attentions in the productions of customizable implants with complex shapes and good mechanical properties. AM fabricated implants of Ti alloy (Ti), stainless steel (SS), cobalt chromium (CoCr), iron (Fe) have been revolutionized in the productions of medical instruments, such as in artificial organs, including heart stents, drug delivery, scaffolds and orthopedic implants. However, high Young's modulus, superior mechanical characteristic, lack of surface integration, high corrosions, failed bone remodeling, and antibacterial performance are still incomparable to be used in anatomical structure. This review studied the issue of metallic implants designed by powder bed fusion of selective laser melting (SLM) techniques on the surface morphology, stress shielding effects, osseointegration, and antibacterial capabilities owing to implant failure. The rate of degradation and corrosion resistance of the metallic SLM implant, which would have an impact on cell proliferation and bone remodeling between the surrounding tissue, were discussed. The current review article also highlighted the various SLM parameters, like mechanical, chemical, and biological modifications, that might enhance the implant. Finally, applications, challenges, opportunities, and future developments of metallic implants using SLM techniques were addressed.

3D-bioprinted bone for regenerative medicine: Current concepts and future perspectives

The shortages in human tissue and organ donors have made clinical therapy relatively challenging. Therefore, research has been initiated over the last decades to develop artificial tissues and organs, particularly from cell and tissue cultures. Three-dimensional (3D) bioprinting is a recent technology capable of building structures for implantation, and these constructs closely resemble native tissues, such as skin, liver, connective tissues, and supportive tissues (bone and cartilage). In this review, we briefly introduce the structure, function, and development of bone tissues, followed by a detailed discussion on 3D bioprinting techniques, materials, and their recent advancements for clinical applications.

Best-in-class modeling: A novel strategy to discover constitutive models for soft matter systems

The ability to automatically discover interpretable mathematical models from data could forever change how we model soft matter systems. For convex discovery problems with a unique global minimum, model discovery is well-established. It uses a classical top-down approach that first calculates a dense parameter vector, and then sparsifies the vector by gradually removing terms. For non-convex discovery problems with multiple local minima, this strategy is infeasible since the initial parameter vector is generally non-unique. Here we propose a novel bottom-up approach that starts with a sparse single-term vector, and then densifies the vector by systematically adding terms. Along the way, we discover models of gradually increasing complexity, a strategy that we call best-in-class modeling. To identify and select successful candidate terms, we reverse-engineer a library of sixteen functional building blocks that integrate a century of knowledge in material modeling with recent trends in machine learning and artificial intelligence. Yet, instead of solving the NP hard discrete combinatorial problem with 216=65,536 possible combinations of terms, best-in-class modeling starts with the best one-term model and iteratively repeats adding terms, until the objective function meets a user-defined convergence criterion. Strikingly, for most practical purposes, we achieve good convergence with only one or two terms. We illustrate the best-in-class one- and two-term models for a variety of soft matter systems including rubber, brain, artificial meat, skin, and arteries. Our discovered models display distinct and unexpected features for each family of materials, and suggest that best-in-class modeling is an efficient, robust, and easy-to-use strategy to discover the mechanical signatures of traditional and unconventional soft materials. We anticipate that our technology will generalize naturally to other classes of natural and man made soft matter with applications in artificial organs, stretchable electronics, soft robotics, and artificial meat.

Extracorporeal organ support for critically ill patients: Overcoming the past, achieving the maximum at present, and redefining the future

Extracorporeal organ support (ECOS) has made remarkable progress over the last few years. Renal replacement therapy, introduced a few decades ago, was the first available application of ECOS. The subsequent evolution of ECOS enabled the enhanced support to many other organs, including the heart [veno-arterial extracorporeal membrane oxygenation (ECMO), slow continuous ultrafiltration], the lungs (veno-venous ECMO, extracorporeal carbon dioxide removal), and the liver (blood purification techniques for the detoxification of liver toxins). Moreover, additional indications of these methods, including the suppression of excessive inflammatory response occurring in severe disorders such as sepsis, coronavirus disease 2019, pancreatitis, and trauma (blood purification techniques for the removal of exotoxins, endotoxins, or cytokines), have arisen. Multiple organ support therapy is crucial since a vast majority of critically ill patients present not with a single but with multiple organ failure (MOF), whereas, traditional therapeutic approaches (mechanical ventilation for acute respiratory failure, antibiotics for sepsis, and inotropes for cardiac dysfunction) have reached the maximum efficacy and cannot be improved further. However, several issues remain to be clarified, such as the complexity and cost of ECOS systems, standardization of indications, therapeutic protocols and initiation time, choice of the patients who will benefit most from these interventions, while evidence from randomized controlled trials supporting their use is still limited. Nevertheless, these methods are currently a part of routine clinical practice in intensive care units. This editorial presents the past, present, and future considerations, as well as perspectives regarding these therapies. Our better understanding of these methods, the pathophysiology of MOF, the crosstalk between native organs resulting in MOF, and the crosstalk between native organs and artificial organ support systems when applied sequentially or simultaneously, will lead to the multiplication of their effects and the minimization of complications arising from their use.

Nanomaterials-Based Hybrid Bioink Platforms in Advancing 3D Bioprinting Technologies for Regenerative Medicine.

3D bioprinting is recognized as the ultimate additive biomanufacturing technology in tissue engineering and regeneration, augmented with intelligent bioinks and bioprinters to construct tissues or organs, thereby eliminating the stipulation for artificial organs. For 3D bioprinting of soft tissues, such as kidneys, hearts, and other human body parts, formulations of bioink with enhanced bioinspired rheological and mechanical properties were essential. Nanomaterials-based hybrid bioinks have the potential to overcome the above-mentioned problem and require much attention among researchers. Natural and synthetic nanomaterials such as carbon nanotubes, graphene oxides, titanium oxides, nanosilicates, nanoclay, nanocellulose, etc. and their blended have been used in various 3D bioprinters as bioinks and benefitted enhanced bioprintability, biocompatibility, and biodegradability. A limited number of articles were published, and the above-mentioned requirement pushed us to write this review. We reviewed, explored, and discussed the nanomaterials and nanocomposite-based hybrid bioinks for the 3D bioprinting technology, 3D bioprinters properties, natural, synthetic, and nanomaterial-based hybrid bioinks, including applications with challenges, limitations, ethical considerations, potential solution for future perspective, and technological advancement of efficient and cost-effective 3D bioprinting methods in tissue regeneration and healthcare.

Introduction of Hybrid Additive Manufacturing for Producing Multi-Material Artificial Organs for Education and In Vitro Testing

The evolution of 3D printing has ushered in accessibility and cost-effectiveness, spanning various industries including biomedical engineering, education, and microfluidics. In biomedical engineering, it encompasses bioprinting tissues, producing prosthetics, porous metal orthopedic implants, and facilitating educational models. Hybrid Additive Manufacturing approaches and, more specifically, the integration of Fused Deposition Modeling (FDM) with bio-inkjet printing offers the advantages of improved accuracy, structural support, and controlled geometry, yet challenges persist in cell survival, interaction, and nutrient delivery within printed structures. The goal of this study was to develop and present a low-cost way to produce physical phantoms of human organs that could be used for research and training, bridging the gap between the use of highly detailed computational phantoms and real-life clinical applications. To this purpose, this study utilized anonymized clinical Computed Tomography (CT) data to create a liver physical model using the Creality Ender-3 printer. Polylactic Acid (PLA), Polyvinyl Alcohol (PVA), and light-bodied silicone (Polysiloxane) materials were employed for printing the liver including its veins and arteries. In brief, PLA was used to create a mold of a liver to be filled with biocompatible light-bodied silicone. Molds of the veins and arteries were printed using PVA and then inserted in the liver model to create empty channel. In addition, the PVA was then washed out by the final product using warm water. Despite minor imperfections due to the printer’s limitations, the final product imitates the computational model accurately enough. Precision adjustments in the design phase compensated for this variation. The proposed novel low-cost 3D printing methodology successfully produced an anatomically accurate liver physical model, presenting promising applications in medical education, research, and surgical planning. Notably, its implications extend to medical training, personalized medicine, and organ transplantation. The technology’s potential includes injection training for medical professionals, personalized anthropomorphic phantoms for radiation therapy, and the future prospect of creating functional living organs for organ transplantation, albeit requiring significant interdisciplinary collaboration and financial investment. This technique, while showcasing immense potential in biomedical applications, requires further advancements and interdisciplinary cooperation for its optimal utilization in revolutionizing medical science and benefiting patient healthcare.

Caregivers of patients with long-term implantable ventricular assist device: a republication of the article published in the Japanese Journal of Artificial Organs.

Implantable ventricular assist device (VAD) has enabled patients with severe heart failure to be discharged from the hospital and to continue their care at home. The presence of caregivers is essential to maintain home care of patients with VAD. The caregivers are mainly the family members who live with the patient with VAD. The caregivers need to be trained (1) VAD device management, (2) disinfection of driveline skin punctures, (3) medication management, and (4) responding to sudden changes. The caregivers' lifestyle is also forced to change. In this article, we discuss the role of caregivers in the VAD era, where long-term support beyond 5years is now possible. This review was created based on a translation of the Japanese review written in the Japanese Journal of Artificial Organs in 2023 (Vol. 52, No. 1, pp. 81-84), with some modifications.