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Artificial cartilage with the help of 3D printing

A new approach to producing artificial tissue has been developed at TU Wien: Cells are grown in microstructures created in a 3D printer.

Is it possible to grow tissue in the laboratory, for example to replace injured cartilage? At TU Wien (Vienna), an important step has now been taken towards creating replacement tissue in the lab – using a technique that differs significantly from other methods used around the world.

A special high-resolution 3D printing process is used to create tiny, porous spheres made of biocompatible and degradable plastic, which are then colonized with cells. These spheroids can then be arranged in any geometry, and the cells of the different units combine seamlessly to form a uniform, living tissue. Cartilage tissue, with which the concept has now been demonstrated at TU Wien, was previously considered particularly challenging in this respect.

Tiny spherical cages as a scaffold for the cells

“Cultivating cartilage cells from stem cells is not the biggest challenge. The main problem is that you usually have little control over the shape of the resulting tissue,” says Oliver Kopinski-Grünwald from the Institute of Materials Science and Technology at TU Wien, one of the authors of the current study. “This is also due to the fact that such stem cell clumps change their shape over time and often shrink.”

To prevent this, the research team at TU Wien is working with a new approach: specially developed laser-based high-resolution 3D printing systems are used to create tiny cage-like structures that look like mini footballs and have a diameter of just a third of a millimeter. They serve as a support structure and form compact building blocks that can then be assembled into any shape.

Stem cells are first introduced into these football-shaped mini-cages, which quickly fill the tiny volume completely. “In this way, we can reliably produce tissue elements in which the cells are evenly distributed and the cell density is very high. This would not have been possible with previous approaches,” explains Prof. Aleksandr Ovsianikov, head of the 3D Printing and Biofabrication research group at TU Wien.

Growing together perfectly

The team used differentiated stem cells – i.e. stem cells that can no longer develop into any type of tissue, but are already predetermined to form a specific type of tissue, in this case cartilage tissue. Such cells are particularly interesting for medical applications, but the construction of larger tissue is challenging when it comes to cartilage cells. In cartilage tissue, the cells form a very pronounced extracellular matrix, a mesh-like structure between the cells that often prevents different cell spheroids from growing together in the desired way.

If the 3D-printed porous spheroids are colonized with cells in the desired way, the spheroids can be arranged in any desired shape. The crucial question is now: do the cells of different spheroids also combine to form a uniform, homogeneous tissue?

“This is exactly what we have now been able to show for the first time,” says Kopinski-Grünwald. “Under the microscope, you can see very clearly: neighboring spheroids grow together, the cells migrate from one spheroid to the other and vice versa, they connect seamlessly and result in a closed structure without any cavities – in contrast to other methods that have been used so far, in which visible interfaces remain between neighboring cell clumps.”

The tiny 3D-printed scaffolds give the overall structure mechanical stability while the tissue continues to mature. Over a period of a few months, the plastic structures degrade, they simply disappear, leaving behind the finished tissue in the desired shape.

First step towards medical application

In principle, the new approach is not limited to cartilage tissue, it could also be used to tailor different kinds of larger tissues such as bone tissue. However, there are still a few tasks to be solved along the way – after all, unlike in cartilage tissue, blood vessels would also have to be incorporated for these tissues above a certain size.

“An initial goal would be to produce small, tailor-made pieces of cartilage tissue that can be inserted into existing cartilage material after an injury,” says Oliver Kopinski-Grünwald. “In any case, we have now been able to show that our method for producing cartilage tissue using spherical micro-scaffolds works in principle and has decisive advantages over other technologies.”

Original publication

O. Kopinski-Grünwald et al., Scaffolded spheroids as building blocks for bottom-up cartilage tissue engineering show enhanced bioassembly dynamics, Acta Biomaterialia, 174, 163 (2024).

Promising target for CAR T-cell therapy leads to potent antitumor responses against cutaneous and rare melanomas

UCLA researchers identified the protein TYRP1 as a potential target for CAR T-cell immunotherapy

Scientists at the UCLA Health Jonsson Comprehensive Cancer Center have built and demonstrated the potential efficacy of a new chimeric antigen receptor (CAR) T-cell-based immunotherapy specifically designed to treat patients with cutaneous and rare subtypes of melanoma.

CAR T-cell therapy uses genetically engineered versions of a patient’s immune cells to target and destroy cancer cells. This type of treatment has transformed the field of cancer, especially for people with challenging-to-treat cancers.

The new approach, described in the journal Nature Communications, uses an engineered CAR T-cell that is designed to recognize and attack cells with high levels of TYRP1, a protein found on the surface of melanoma cells. The team found these engineered CAR T-cells can effectively eliminate cancer cells in preclinical tests without causing severe side effects.

“One of the biggest challenges in CAR T-cell therapies is the scarcity of suitable tumor targets,” said Cristina Puig-Saus, PhD, assistant professor of medicine at the David Geffen School of Medicine at UCLA and senior author of the study. “While TYRP1 has previously been targeted in clinical trials using monoclonal antibodies, this new approach harnesses the power of CAR T-cell therapy and has led to very good anti-tumor responses, improving the treatment’s overall effectiveness.”

Despite the success of immune checkpoint blockade, a considerable number of patients with melanoma either do not respond well or experience relapse after initial success. Scientists are exploring new ways to create more precise and effective treatments. Moreover, rare subtypes of melanoma present additional challenges due to their resistance to standard therapies, including immunotherapies like immune checkpoint blockade.

To find better ways to use CAR T-cell immunotherapy to treat melanoma, the team first looked to find an antigen that could be used to target a protein that is expressed on the surface of the cancer cells, but presents lower expression in normal cells.

Through analyzing three different melanoma datasets, they identified TYRP1, which plays a key role in melanin synthesis, and its surface expression is more prominent in melanoma cells than in normal tissues.

They found approximately 30% of patients with cutaneous melanoma present high overexpression of TYRP1. Importantly, the percentage of overexpression was even higher in patients with rare melanomas. The authors showed that 60% of patients with acral and mucosal melanoma and around 90% of patients with uveal melanoma overexpress TYRP1.

“This protein is intracellular, but a small portion gets to the plasma membrane as part of the vesicular transport of the cell, and gets endocytosed again after a short period of time. While in the cell surface, it becomes a target for the CAR T-cells,” said Puig-Saus, who is a member of the UCLA Health Jonsson Comprehensive Cancer Center and the Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research at UCLA.

To investigate the potential new target, the team designed a CAR construct that specifically targeted cells with elevated TYRP1 expression and then tested the newly engineered CAR T-cell in different types of melanoma models.

With this design, they found the CAR T-cells completely eradicated cancer cells in both cell lines and animal models, showcasing promising results without inducing toxicity or causing adverse effects related to the treatment.

“These preclinical results pave the way for clinical trials, where the TYRP1-targeting CAR T-cell therapy can be tested in patients with all different types of melanomas,” said Puig-Saus. “If proven safe and effective in human trials, this treatment presents an exciting prospect for future advancements in the fight against cancer.”

The research team is planning to move forward with a clinical trial to assess the therapy’s safety and effectiveness in treating patients with melanoma.

The study’s co-first authors are Sameeha Jilani, Justin Saco and Edurne Mugarza in the department of hematology/oncology at the David Geffen School of Medicine at UCLA. Other UCLA study authors include Aleida Pujol-Morcillo, Jeffrey Chokry, Clement Ng, Gabriel Abril-Rodriguez, David Berger-Manerio, Ami Pant, Jane Hu, Rubi Gupta, Agustin Vega-Crespo, Ignacio Baselga-Carretero, Jia Chen, Daniel Sanghoon Shin, Philip Scumpia, Roxana Radu, Yvonne Chen and Antoni Ribas.

The work was supported in part by the Parker Institute for Cancer Immunotherapy, Department of Defense, California Institute for Regenerative Medicine, Melanoma Research Alliance and the National Institutes of Health.

A “heart on a chip”

Developed in Montreal, the device – a 3D-bioprinted, miniaturized chip – promises to advance understanding of cardiovascular disease and aid in the development of new precision treatments.

Scientists at the Centre de recherche Azrieli du CHU Sainte-Justine, affiliated with Université de Montreal, have developed a device that accurately simulates the electrical activity, mechanics and physiology of a human heart.

Dubbed a “heart on a chip,” it’s been 3D-bioprinted using a bioink and promises to aid in better understanding the specific nature of individual cases of heart disease, as well as develop new treatments and accurately assess their efficacy in an automated, high-throughput manner.

Developed by a team led by UdeM pharmacology professor Houman Savoji and doctoral student Ali Mousavi, the device and its bioink are described in a study published in the journal Applied Materials Today.

Since the heart is a vital organ, its activity can’t be directly analyzed “live” at the cellular level. Hence the usefulness of the “heart on a chip,” a sort of ring-shaped tissue made up of the patient’s own cells, mimicking as closely as possible the complexity of the human heart.

These devices are usually produced individually in laboratories in a non-standardized way.

“Our research has made it possible to combine 3D bioprinting technology to produce standard hearts-on-a-chip much more quickly and precisely,” said Savoji. “What’s more, our results show that printed devices perform better than those produced manually.”

The ring-shaped heart tissues are printed with a bioink containing a patient’s stem cells.

“We’ve formulated a bioink that best reproduces the properties of the heart, such as elasticity and electrical conductivity, and has suitable properties required for 3D bioprinting,” said Mousavi, the study’s first author, who’s doing his PhD at the Institute of Biomedical Engineering.

The device opens up new prospects for the identification of new drugs, he added.

“The next step will be to compare healthy and diseased heart cells to develop solid cardiac pathology models. That will also let us safely and accurately test the effect of new therapeutic molecules on cells.”

The ultimate goal is to be able to use the cells of cardiac patients to model their heart disease and validate the efficacy of treatments available for their condition – a big step towards personalized medicine.

 

About this study

“Development of photocrosslinkable bioinks with improved electromechanical properties for 3D bioprinting of cardiac BioRings,” by Ali Mousavii et al, is published in the February 2024 issue of Applied Materials Today. The project was funded by the Natural Sciences and Engineering Research Council, the Fonds de recherche du Québec – Santé and TransMedTech Institute. Ali Mousavi is also the recipient of a doctoral research grant from Fonds de recherche du Québec – Santé.

Engineered cartilage could turn the tide for patients with osteoarthritis

Team is studying how pluripotent stem cells develop into cartilage tissues. By replicating that process, they are developing a procedure to engineer tissues that could be used to repair damaged cartilage and stop disease progression.

Key takeaways

  • Treatments for degenerative joint disease are limited because articular cartilage doesn’t heal efficiently after injury or as people age.
  • A team at Boston Children’s is studying how pluripotent stem cells develop into cartilage tissues.
  • By replicating that process, they are developing a procedure to engineer tissues that could be used to repair damaged cartilage and stop disease progression.

 

About one in seven adults live with degenerative joint disease, also known as osteoarthritis (OA). In recent years, as anterior cruciate ligament (ACL) injury and other joint injuries have become more common among adolescent athletes, a growing number of 20- and 30-somethings have joined the ranks of aging baby boomers living with chronic OA pain.

Treatments for degenerative joint disease are limited, largely because the cartilage that protects the joints doesn’t regenerate after birth. Without a way to stimulate regrowth of damaged cartilage, most treatments focus on managing symptoms. And with few curative treatment options, OA remains one of the leading causes of pain and disability in the United States.

Boston Children’s researcher April Craft, PhD, and her team want to change that. Their approach: “grow” cartilage in the lab that could be used to replace damaged articular tissues in patients’ joints.

Lessons in cartilage and degenerative disease

The team first set out to understand how cartilage and joint tissues develop naturally and how stem cells differentiate into cartilage cells, or chondrocytes. The next step was to replicate that process in the lab, putting cells through the same stages of development.

In a study published in BMJ, members of the Craft Lab described their approach for generating cartilage from induced pluripotent stem cells (iPSC). Derived from patients’ own cells, iPSCs can give rise to virtually any type of cell in the body, including chondrocytes. The team generated cartilage-like tissues from two patients with progressive pseudorheumatoid arthropathy of childhood (PPAC), a genetic condition that causes severe premature joint degeneration.

“We chose to study PPAC because joint degeneration in this condition progresses rapidly toward a state that is indistinguishable from end-stage OA,” says Craft. “Our iPSC model of PPAC cartilage will help us learn about this devastating disease.” Their findings may possibly apply more broadly to OA from acute injuries or chronic overuse, as well as provide the basis for future therapeutics development.

Generating treatment options for degenerative joint disease

Using cartilage engineered in the Craft Lab, the team has successfully repaired damaged joint tissues in rats and is preparing to test the procedure in large animals.

Because joint-lining cartilage is avascular and the implanted chondrocytes will be encased by the cartilage tissue itself, there is a reduced likelihood of implant rejection. Because of this, Craft believes that someday “off-the-shelf” cartilage for human patients could be created using one cell line. If so, live cartilage tissues could be produced, stored, and delivered to surgical teams as needed to replace damaged cartilage.

In some ways, the procedure resembles the most advanced cell therapy for cartilage: autologous chondrocyte implantation. In this two-procedure process, chondrocytes are harvested from one area of the body, expanded in number, and then implanted into the damaged area.

Off-the-shelf cartilage implants would allow patients to undergo just one surgical procedure rather than two. Replacing damaged cartilage with a piece of new cartilage that was generated ahead of time would omit the delay in manufacturing associated with autologous cartilage harvesting, reduce the rehabilitation time, and allow patients to return to their normal activities sooner after surgery.

The first humans to receive this novel implant would likely be patients who have pain and joint damage but haven’t yet progressed to severe degeneration. And eventually, it could be tried in others, such as athletes with joint damage.

“This could have a profound impact on people as they age as well as athletes experiencing joint pain,” says Craft.

Study describes five cutting-edge advances in biomedical engineering

The paper was written by a consortium of 50 researchers from 34 universities around the world and laid the foundation for a concerted worldwide effort to achieve technological and medical breakthroughs.

Original Source: Medical Xpress

IEEE, the world’s largest technical professional organization dedicated to advancing technology for humanity, and the IEEE Engineering in Medicine and Biology Society (IEEE EMBS), published a detailed position paper on the field of biomedical engineering titled “Grand Challenges at the Interface of Engineering and Medicine.”

The paper, published in the IEEE Open Journal of Engineering in Medicine and Biology (IEEE OJEMB), was written by a consortium of 50 researchers from 34 universities around the world and laid the foundation for a concerted worldwide effort to achieve technological and medical breakthroughs.

“What we’ve accomplished here will serve as a roadmap for groundbreaking research to transform the landscape of medicine in the coming decade,” said Dr. Michael Miller, senior author of the paper and professor and director of the Department of Biomedical Engineering at Johns Hopkins University. “The outcomes of the task force, featuring significant research and training opportunities, are poised to resonate in engineering and medicine for decades to come.”

The position paper was the result of a two-day workshop organized by IEEE EMBS and the Department of Biomedical Engineering at Johns Hopkins University and the Department of Bioengineering at the University of California San Diego. Through the course of the workshop, the researchers identified five primary medical challenges that have yet to be addressed, but, by solving them with advanced biomedical engineering approaches, can greatly improve human health.

One of the participants in the workshop was Paolo Bonato, Ph.D., director of the Motion Analysis Laboratory at Spaulding Rehabilitation, a member of Mass General Brigham, and associate professor of Physical Medicine and Rehabilitation at Harvard Medical School.

“This manuscript is a unique contribution by 50 key players in the field of biomedical engineering highlighting areas of future technical developments that are expected to enable advanced precision medicine interventions,” said Bonato.

“The future of medicine is expected to heavily rely on advances in biology and technology, and we can achieve this goal by collecting an unprecedented amount of high-quality data that will inform digital twin models and, hence, develop patient-specific therapy plans or even predict and prevent the development of diseases.”

“This paper represents a major milestone in the advancement of biomedical engineering, which could only have been achieved through close collaboration rather than the work of many siloed individuals,” added consortium member Dr. Metin Akay, founding chair of the Biomedical Engineering Department at the University of Houston and Ambassador of IEEE EMBS.

“We have a shared commitment to advancing patient-centric technologies, and health care efficacy and accessibility—which extends beyond —and elevating health care quality, reducing costs and improving lives worldwide.”

By focusing on these five medical challenges facing biomedical engineering, the consortium has laid out a roadmap for future research and funding:

Bridging precision engineering and precision medicine for personalized physiology avatars

In an increasingly digital age, we have technologies that gather immense amounts of data on patients, which clinicians can add to or pull from. Making use of this data to develop accurate models of physiology, called “avatars”—which take into account multimodal measurements and comorbidities, concomitant medications, potential risks, and costs—can bridge individual patient data to hyper-personalized care, diagnosis, risk prediction, and treatment.

Advanced technologies, such as wearable sensors and digital twins, can provide the basis of a solution to this challenge.

The pursuit of on-demand tissue and organ engineering for human health

Tissue engineering is entering a pivotal period in which developing tissues and organs on demand, either as permanent or temporary implants, is becoming a reality.

To shepherd the growth of this modality, key advancements in stem cell engineering and manufacturing—along with ancillary technologies such as gene editing—are required. Other forms of stem cell tools, such as organ-on-a-chip technology, can soon be built using a patient’s own cells and can make personalized predictions and serve as “avatars.”

Revolutionizing neuroscience using artificial intelligence (AI) to engineer advanced brain-interface systems

Using AI, we have the opportunity to analyze the various states of the brain through everyday situations and real-world functioning to pinpoint pathological brain function noninvasively. Creating technology that does this is a monumental task, but one that is increasingly possible. Brain prosthetics, which supplement, replace, or augment functions, can relieve the disease burden caused by neurological conditions.

Additionally, AI modeling of brain anatomy, physiology, and behavior, along with the synthesis of neural organoids, can unravel the complexities of the brain and bring us closer to understanding and treating these diseases.

Engineering the immune system for health and wellness

With a heightened understanding of the fundamental science governing the immune system, we can strategically make use of the  to redesign human cells as therapeutic and medically invaluable technologies.

The application of immunotherapy in cancer treatment provides evidence of the integration of engineering principles with innovations in vaccines, genome, epigenome, and protein engineering, along with advancements in nanomedicine technology, functional genomics, and synthetic transcriptional control.

Designing and engineering genomes for organism repurposing and genomic perturbations

Despite the rapid advances in genomics in the past few decades, there are obstacles remaining in our ability to engineer genomic DNA. Understanding the design principles of the human genome and its activity can help us create solutions to many different diseases that involve engineering new functionality into human cells, effectively leveraging the epigenome and transcriptome, and building new cell-based therapeutics.

Beyond that, there are still major hurdles in gene delivery methods for in vivo gene engineering, in which we see biomedical engineering as a component of the solution to this problem.

“These grand challenges offer unique opportunities that can transform the practice of engineering and medicine,” remarked Dr. Shankar Subramaniam, lead author of the task force, distinguished professor of Shu Chien-Gene Lay Department of Bioengineering at the University of California San Diego and past President of IEEE EMBS.

“Innovations in the form of multi-scale sensors and devices, creation of humanoid avatars, and the development of exceptionally realistic predictive models driven by AI can radically change our lifestyles and response to pathologies. Institutions can revolutionize education in biomedical and engineering, training the greatest minds to engage in the most important problem of all times—human health.”

 

More information: Shankar Subramaniam et al, Grand Challenges at the Interface of Engineering and Medicine, IEEE Open Journal of Engineering in Medicine and Biology (2024). DOI: 10.1109/OJEMB.2024.3351717

3D in vitro human atherosclerosis model for high-throughput drug screening

3D, three-layer nanomatrix vascular sheet that possesses multiple features of atherosclerosis has been applied for developing a high-throughput functional assay of drug candidates to treat this disease

A groundbreaking 3D, three-layer nanomatrix vascular sheet that possesses multiple features of atherosclerosis has been applied for developing a high-throughput functional assay of drug candidates to treat this disease, University of Alabama at Birmingham researchers report in the journal Biomaterials.

“Current in vitro atherosclerosis models have significant limitations, including the lack of three-layer vascular architecture and limited atherosclerotic features,” said Ho-Wook Jun, Ph.D., a professor in the UAB Department of Biomedical Engineering and the corresponding author. “Moreover, no scalable 3D atherosclerosis model is available for the evaluation of potential therapeutics via high-throughput assays.”

Cardiovascular disease — primarily caused by atherosclerosis — is the leading cause of death in the United States. In the development of effective therapies for atherosclerosis, in vitro models are commonly utilized to assess the efficacy and safety of novel therapeutics before proceeding to complex in vivo and clinical studies.

Recently, the United States Food and Drug Agency Modernization Act 2.0 has permitted the use of alternative models other than animals for drug testing before progressing to human trials. This transformative change in regulations serves as a driving force, inspiring the pursuit of advanced in vitro models, such as cell-based assays and organoid- or artificial intelligence-based models that are capable of replacing or reducing animal use in assessing drug efficacy and safety. The goal is to expedite progression from preclinical research to human clinical trials via a more efficient and cost-effective drug development process.

The novel in vitro 3D, three-layer nanomatrix vascular sheet with critical atherosclerosis multi-features, or VSA, includes endothelial cell dysfunction, monocyte recruitment, presence of macrophages, extracellular matrix remodeling, smooth muscle cell phenotype transition, inflammatory cytokine secretion, foam cells and calcification initiation. The VSA thus provides a human atherosclerosis-mimicking environment for drug evaluation.

The three layers of the robust vascular sheet, or VS, structure are composed of: 1) human aortic endothelial cells, 2) human aortic smooth muscle cells and 3) human aortic adventitial fibroblasts layers. These mimic the layered structure of the native vascular wall, which, from inside out, is composed of the tunica intima, tunica media and tunica adventitia tissues. The researchers created the critical atherosclerosis multi-features by adding monocytes and various pro-atherosclerotic cytokines, colony-stimulating factors and oxidized low-density lipoprotein to stimulate atherogenesis on the 3D, layered nanomatrix vascular sheet.

Co-first author Jun Chen, Ph.D., and colleagues used this VSA system to create high-throughput functional assays by fabricating multiple VSAs in 48-well plates. The VSAs were subjected to drug treatments and then were comprehensively characterized, with a focus on evaluating foam cells, inflammation and atherosclerosis-associated genes.

High-throughput functional assays were validated using two classic atherosclerosis drugs, rosuvastatin and sirolimus, and were used to evaluate two drug candidates, curcumin and colchicine, and a potential gene therapy candidate, microRNA-146a-loaded liposomes, for treating atherosclerosis. The researchers found that the VSAs replicated a number of results seen by others in in vivo tests of these treatments. “The high efficiency and scalability of the VSA-evaluated functional assays should facilitate drug discovery and development for atherosclerosis,” Chen said.

“Our study focuses on demonstrating the use of VSAs as a cost-effective and efficient way to investigate therapeutic effectiveness,” Jun said. “The VSAs offer a high-throughput methodology and allow for a relatively large number of biological replicates, also making them ideal for mechanistic research. For instance, VSAs can be customized to induce atherosclerosis on single-, double- or three-layer structures, which provides insights into the effect of discrete layers on atherogenesis, particularly the fibroblast layer. Furthermore, the vascular sheets can be scaled up to develop high-throughput assays for drug safety testing, helping determine pharmacological and toxicological parameters for use in animal models.”

The Birmingham-based Endomimetics, LLC, has licensed the new 3D, three-layer nanomatrix vascular sheet atherosclerosis model technology through UAB’s Bill L. Harbert Institute for Innovation and Entrepreneurship, which manages university intellectual property.

“The atherosclerosis drug market is a large and growing segment of the pharmaceutical industry,” said Joseph Garner, Ph.D., CEO of Endomimetics. “This market is experiencing significant growth due to the rising prevalence of cardiovascular diseases, advancements in pharmaceutical research and the development of innovative atherosclerosis treatments. By 2032, this market is projected to reach $26.9 billion with a 2.8 percent compound annual growth rate from 2023 to 2032. North America currently holds the dominant market share at more than 41 percent.”

Brigitta Brott, M.D., a co-author and an interventional cardiologist and professor in the UAB Department of Medicine Division of Cardiovascular Disease, said, “Endomimetics and UAB will collaborate with pharmaceutical companies to evaluate potential candidates for atherosclerosis treatment, utilizing our VSA-based efficacy and safety assays. This approach can also be extended to assess other drugs for conditions such as diabetes, obesity and liver-related diseases, where atherosclerosis is prevalent among many patients.”

Endomimetics anticipates providing this innovative atherosclerosis model this spring for evaluating various types of potential therapeutics. “Our atherosclerosis assays will pave the way for therapeutic candidates directly targeting human plaque and the atherosclerotic artery wall, and they will generate extensive predictive data on their responses, which is crucial for defining the therapeutic window of these candidates and providing essential groundwork for future studies,” Jun said.

At Endomimetics, Jun is chief scientific officer and Brott is chief medical officer.

Co-authors with Jun, Chen and Brott in the study, “Atherosclerotic three-layer nanomatrix vascular sheets for high-throughput therapeutic evaluation,” are Xixi Zhang, Robbie Cross Jr., Yujin Aha, Gillian Huskin, UAB Department of Biomedical Engineering; Will Evans, Augusta University/University of Georgia Medical Partnership, Athens, Georgia; Patrick Taejoon Hwang, Endomimetics; Jeong-a Kim, UAB Department of Medicine Division of Endocrinology and Metabolism; Hanjoong Jo, Georgia Institute of Technology and Emory University, Atlanta, Georgia; and Young-sup Yoon, School of Medicine, Emory University. Zhang is a co-first author.

Support came from National Institutes of Health grant HL163802.

“The successful private-public collaboration between Endomimetics and UAB demonstrates how UAB provides potential collaborators a great environment to research and develop innovative ideas to tackle clinically significant problems,” Jun said. “The Endomimetics team appreciates the excellent working relationship that exists among the company, the UAB School of Engineering, the Marnix E. Heersink School of Medicine, and the Bill L. Harbert Institute for Innovation and Entrepreneurship at UAB.”

At UAB, Medicine is a department in the Heersink School of Medicine, and Biomedical Engineering is a joint department in the schools of Engineering and Medicine.

Ultrasound-activated sono-inks could print 3D structures inside the human body

A novel technique that uses ultrasound to create objects from sonically cured inks could enable 3D printing at deep penetration depths, potentially including inside the body

Original Source: Physics World

A team of US-based researchers has pioneered an innovative 3D printing technique that uses ultrasound waves to create objects from sonically cured inks. The new approach, dubbed deep-penetrating acoustic volumetric printing (DAVP), could potentially enable printing to be carried out inside the human body – paving the way for a range of minimally invasive procedures such as tissue engineering or targeted localized drug delivery.

Publishing their findings in Science, the researchers describe how they successfully used DAVP to perform 3D printing at centimetre depths through biological tissue and create intricate structures within a variety of different materials – thus demonstrating its effectiveness with materials like hydrogels and nanocomposites, which are crucial in biomedical applications.

As co-senior author Junjie Yao from Duke University’s Photoacoustic Imaging Lab (PI-Lab) explains, the newly created sonicated ink (or sono-ink) contains a mixture of polymers, particles and chemical initiators specifically designed to form a gel when the ink absorbs sound waves. When exposed to high-intensity focused ultrasound, these self-enhancing fluids solidify in precise patterns, enabling the creation of complex structures.

“This is achieved through the unique properties of the sono-inks, which are formulated for optimal response to ultrasound, enabling a deeper penetration at higher resolution compared to conventional light-based printing methods,” he says.

According to Yao, a key finding of the research is the discovery that the new technique overcomes the physical and optical limits of existing approaches to additive manufacturing, and enables users to “print at depths and in materials previously unachievable by other 3D printing methods”, in particular light-based approaches that are ineffective in opaque or optically scattering media.

The team also speculates that, amongst other things, the technique could help to treat bone defects through the in situ fabrication of artificial bone – and that printed materials formed with sono-ink could elute drugs, thus facilitating localized chemotherapy to prevent the recurrence of tumours after resection.

“[The technique] opens up significant potential applications in clinical and healthcare settings, such as creating scaffolds for tissue engineering, or targeted localized drug delivery systems within the body,” says Yao.

Improved patient outcomes

Elsewhere, co-senior author Yu Shrike Zhang, at Brigham and Women’s Hospital, Harvard Medical School, points out that the primary advantage of DAVP in clinical settings is its minimally invasive nature. In particular, he draws attention to the fact that the new technique can “potentially print biocompatible materials directly inside the body” and thus help mitigate the “invasive and risky” nature of many traditional surgical procedures.

“This could revolutionize treatments by allowing for precise, targeted interventions without traditional surgery, significantly reducing recovery times and improving patient outcomes. Additionally, the versatility in materials and the ability to work in opaque environments make it particularly suitable for varied medical applications,” he says.

Moving forward, Zhang confirms that the team plans to further refine the DAVP technique, with a particular focus on optimizing the sono-inks and the ultrasound printing technology to deliver even greater precision, versatility and biocompatibility.

“Collaborations with medical researchers are planned to explore the practical application of this technology in clinical and healthcare settings,” he adds. “We aim to develop prototypes for specific medical applications, such as regenerative medicine and targeted localized drug delivery, and conduct trials to evaluate their effectiveness and safety in a clinical environment.”

3D bioprinting sheds light on why blood vessel curvature may foster brain cancer metastasis

The team developed a specialized bioink tailored explicitly for creating brain blood vessels.

Original Source: Medical Xpress

Recent research suggests that the winding paths of blood vessels might trigger the development of metastatic cancers, a topic gaining considerable attention in academia. A collaborative team utilized 3D bioprinting technology to reproduce intricate brain blood vessel structures in the laboratory.

Their primary focus was on uncovering the impact of  vessel curvature on the movement of tumor cells circulating within the brain. The research findings are published in Nature Communications.

Brain metastasis, often categorized as terminal due to its grim prognosis and the challenges in treatment, occurs when , having detached from other tissues, navigate the intricate maze of blood vessels deep within the brain to initiate the disease.

While several in vitro models have been developed to study its onset mechanisms, understanding the impact of physiological factors within brain blood vessels and their anatomical structures on metastatic  development has been a significant hurdle.

The team developed a specialized bioink tailored explicitly for creating brain blood vessels. The models 3D-printed using conventional ink faced challenges in accurately replicating intricate cerebral vasculature, as they encountered difficulty in preserving the structure until complete solidification.

To tackle this issue, the team created a hybrid brain-derived decellularized extracellular matrix (BdECM) by blending decellularized extracellular matrix sourced from the brain with alginate extracted from seaweed. This innovative hybrid BdECM, comprising collagen and some 2,000 other protein types, rapidly stabilizes after printing, enabling the precise replication of more intricate brain blood vessel structures than previously achievable.

The team utilized this advanced technology to engineer functional brain blood vessels comprising multiple cellular layers—endothelial, surrounding, and astrocyte/neuron layers—with varying curvatures. Their analysis of how circulating tumor cells responded to the cerebral vascular structure revealed a crucial finding: an increase in blood vessel curvature can correlate with a heightened adherence of cancer cells to the vessel walls.

Furthermore, the team investigated the molecular-level mechanisms underlying metastatic cancer development through the interactions between cancer cells and brain vascular tissues.

Subsequently, the researchers employed  with the brain blood  model to examine factors like blood flow velocity and wall shear stress and biophysically explored the correlation between cerebral vascular curvature and cancer cell extravasation.

The research team was led by Professor Dong-Woo Cho and Ph.D. candidate Wonbin Park from the Department of Mechanical Engineering at Pohang University of Science and Technology (POSTECH), along with Professor Byoung Soo Kim and Ph.D. candidate Jae-Seong Lee from the School of Biomedical Convergence Engineering at Pusan National University, and Professor Ge Gao from the School of Medical Technology at Beijing Institute of Technology.

Professor Dong-Woo Cho explained, “By examining the molecular and dynamic elements of cancer extravasation through bioprinted cerebrovascular models, we’ve delved into the disease’s onset mechanisms. We envision leveraging this technology for drug development aimed at treating  metastasis.”

More information: Wonbin Park et al, 3D bioprinted multilayered cerebrovascular conduits to study cancer extravasation mechanism related with vascular geometry, Nature Communications (2023). DOI: 10.1038/s41467-023-43586-4

Drugs of the future will be easier and faster to make, thanks to mRNA – after researchers work out a few remaining kinks

Better understanding how mRNA-based drugs interact with the immune system and how they are degraded in human cells can help lead to safe, durable and effective treatments for a wide range of diseases.

Original Source: Li Li, The Conversation

Vaccines have been reliably and affordably protecting people from diseases worldwide for centuries. Until the COVID-19 pandemic, however, vaccine development was still a long and idiosyncratic process. Traditionally, researchers had to tailor manufacturing processes and facilities for each vaccine candidate, and the scientific knowledge gained from one vaccine was often not directly transferable to another.

But the COVID-19 mRNA vaccines brought a new approach to vaccine development that has far-reaching implications for how researchers make drugs to treat many other diseases.

I am a biochemist, and my lab at UMass Chan Medical School focuses on developing better ways to use mRNA as a drug. Although there are many possibilities for what researchers can use mRNA to treat, some important limitations remain. Better understanding how mRNA-based drugs interact with the immune system and how they are degraded in human cells can help lead to safe, durable and effective treatments for a wide range of diseases.

Some basics of mRNA drugs

Messenger RNA, or mRNA, is made of four building blocks denoted by the letters A, C, G and U. The sequence of letters in an mRNA molecule conveys genetic information that directs how a protein is made.

An mRNA drug comprises two essential components: mRNA molecules, which code for desired proteins, and the lipid molecules – such as phospholipids and cholesterol – that encapsulate them. These mRNA-lipid nanoparticles, or LNPs, are tiny spheres about 100 nanometers in diameter that protect mRNA from degradation and facilitate its delivery into target cells.

Once inside cells, mRNA molecules instruct the cell’s machinery to produce the target protein required for a desired therapeutic effect. For example, the mRNA in the Pfizer-BioNTech and Moderna COVID-19 vaccines directs cells to produce a harmless version of the virus’ spike protein that trains the immune system to recognize and better prepare for potential infection.

From a drug development perspective, mRNA drugs offer significant advantages over traditional drugs because they are easily programmable. Hundreds of pounds of mRNA can be made from readily available DNA templates, such that producing a different mRNA drug is as simple as changing the corresponding DNA templates.

More importantly, different mRNA drugs produced by the same set of methods will have similar properties. They will be delivered to the same tissues, trigger similar levels of immune responses and degrade in similar ways. This predictability significantly reduces the development risks and financial costs of developing mRNA drugs.

In addition to being easy to program, mRNA drugs have several other unique properties. For example, just like the mRNAs your body naturally produces, therapeutic mRNAs have a short half-life in cells: about one day. As a result, current mRNA technology is ideal for treatments that aren’t meant to last long in the body.

This is why vaccines are popular candidates for mRNA technology: They provide long-term protection against disease after brief exposure to the drug with few side effects. There are currently more than 30 mRNA vaccine candidates, not including vaccines for COVID-19, in clinical trials.

Self vs. nonself

Another critical feature of mRNA drugs is their intrinsic ability to stimulate the immune system. This may sound paradoxical – after all, your cells already contain large amounts of mRNAs. Why would other mRNAs activate your immune system? How does your immune system distinguish between self and nonself mRNAs?

The first reason involves location. Therapeutic mRNAs enter cells using endosomes – sacs made of the cell’s membrane that take in materials from the cell’s environment. Your immune system can detect mRNA in endosomes because this is usually a sign of an RNA virus infection – cellular mRNAs normally don’t enter endosomes. When your immune system labels therapeutic mRNAs as viral material, it triggers a strong inflammatory response that can lead to severe side effects.

One solution to this problem is to modify mRNA’s building blocks – specifically, changing the U, or uridine, to its chemical cousins, pseudouridine and N1-methylpseudouridine. This subtle chemical change prevents the unwanted immune response while allowing the therapeutic mRNA to direct the cell to make the protein it encodes. The 2023 Nobel Prize in physiology or medicine was awarded to the scientists who made this breakthrough discovery. Both the Pfizer-BioNTech and Moderna COVID-19 mRNA vaccines use this technique.

The second source of unwanted immune response is impurities from mRNA production. To prepare mRNA from a DNA template, scientists use a protein called RNA polymerase that tends to make a small amount of side product called double-stranded RNA. Unlike mRNA, which is single-stranded, double-stranded RNA has two chains that form a double helix. RNA viruses also form double-stranded RNA when they replicate, and exposing cells to double-stranded RNA can lead to a strong immune response.

Removing double-stranded RNA is challenging, especially at the industrial scale. Fortuitously, for mRNA vaccines, the residual amount of double-stranded RNA can stimulate the immune system to enhance antibody responses. However, for applications other than vaccines, a cleaner RNA product is necessary to reduce side effects.

Moving beyond vaccines

Although mRNA has the potential to transform drug development for various medical purposes, careful consideration is required to identify targets that align with the technology’s strengths.

For example, because there is currently a limit to how long mRNA can last in the body, treatments that need a protein to be present for only a short period of time to achieve a lasting therapeutic effect are ideal. One promising example in development is using mRNA that encodes CRISPR-Cas9 gene-editing proteins to knock out genes that cause specific diseases.

Researchers are exploring this strategy to develop a single-dose treatment for hereditary transthyretin amyloidosis, a rare genetic disease caused by the accumulation of misfolded proteins in the heart and nerves. This disease is an ideal target for mRNA-based CRISPR gene therapy because the target protein is produced by the liver. Because most drugs pass through the liver, this makes it easier to deliver CRISPR-Cas9 mRNA to its target. In the next few years, a new generation of more precise mRNA-based genome editing therapies will enter clinical trials.

For treatments that need a specific protein to be present in the body for long periods of time or need to prompt little to no immune reaction, further advancements in mRNA technology are necessary to extend mRNA’s half-life and eliminate immune-triggering contaminants. Notable new developments in these areas include using computational algorithms to optimize mRNA sequences in ways that enhance their stability and engineering RNA polymerases that introduce fewer side products that may cause an immune response.

Further advancements have the potential to enable a new generation of safe, durable and effective mRNA therapeutics for applications beyond vaccines.

New heart treatment helps the body grow a replacement valve

Replacement heart valves that grow inside the body are a step closer to reality following studies led by researchers.

Surgery to replace faulty heart valves has been possible for more than 60 years, but the treatment has medical drawbacks, both with mechanical or biological valves. But what if the body’s natural repair mechanisms could be harnessed to build a living heart valve, right where it is needed? Recent studies led by researchers at Harefield Hospital and Imperial’s National Heart and Lung Institute suggest that this approach is entirely possible.

Heart valve replacement is a life-saving treatment, but it is rarely a long-term solution. Both mechanical and biological valves have their own drawbacks. Patients with mechanical valves must take drugs for the rest of their lives to prevent blood clotting. Biological valves, on the other hand, only last between 10 to 15 years. The treatment is particularly challenging for children with congenital heart defects, as the valves do not grow along with their bodies and must be replaced several times before they reach adulthood.

The new approach developed by Sir Magdi Yacoub’s team at Harefield and Imperial is much more adaptable. “The aim of the concept we’ve developed is to produce a living valve in the body, which would be able to grow with the patient,” says Dr Yuan-Tsan Tseng, a biomaterials scientist working at the National Heart and Lung Institute and the Harefield Heart Science Centre.

The procedure begins with a nanofibrous polymeric valve, but made from a biodegradable polymer scaffold rather than a durable plastic. “Once this is inside the body, the scaffold recruits cells and instructs their development, so that the body works as a bioreactor to grow new tissue,” Dr Tseng explains. “The scaffold gradually degrades and is replace by our body’s own tissues.”

The scaffold material used to make the valve is the key innovation. “It has the capability to attract, house, and instruct appropriate cells from the patient’s own body, thereby facilitating tissue generation and maintaining valve function.”

Building up, breaking down

The design and manufacture of the valve is set out in a recent academic paper*, along with validation of its performance in the laboratory and the first results of animal tests. The valves were transplanted into sheep and monitored for up to six months. “The valves performed very well,” says Dr Tseng. “They continued to function for the six months of the trial, and also showed good cellular regeneration.”

In particular, the study shows that the scaffold was able to attract cells from the blood stream which then developed into functional tissues, a process known as endothelial-to-mesenchymal transformation (EndMT). “We’ve also seen nerves and fatty tissues growing in the scaffold, as we might expect in a normal valve.”

Meanwhile, the polymer could be seen degrading to make way for the new tissue. This degradation process was followed with the help of gel permeability chromatography (GPC) in the Agilent Measurement Suite (AMS), a facility in Imperial’s Molecular Sciences Research Hub in White City fitted out with advanced analytical instrumentation provided by Agilent.

“GPC was able to tell us the molecular weight of the polymer in samples taken from the valves at various time points during the in-vivo study,” Dr Tseng says. This showed that the structure was gradually being broken down, but without affecting the valve’s performance.

“If there was no regeneration, the valve would fall apart as the polymer degrades. But what we see is continuing functionality, and that means cell regeneration is taking place over time. That proves that our idea of in-vivo regeneration is working.”

More work is required to determine exactly which processes are causing the polymer to degenerate and how closely it is linked to tissue regeneration. “But the tissue regeneration is definitely sufficient to cover the structural integrity and functionality of the valve,” says Dr Tseng.

On to clinical trials

The next step is to continue the animal studies, to follow the tissue regeneration process for longer. This data will be essential in order to get regulatory approval for the first clinical trials, hopefully in the next five years or so.

Further work will also be required on the processes used to manufacture the valves. “There are various improvements to make on the manufacturing side, and we will potentially use the Agilent Measurement Suite again to help us optimise the polymer, so that it is performing in the desired way,” Dr Tseng says.

This demonstrates the continuing role that the facilities Imperial can play advancing innovation. “At the Agilent Measurement Suite we have a wide range of the state-of-the-art analytical instrumentation and expertise that can serve medical and biological research communities,” says Professor Marina Kuimova, Director of the AMS. “The work of Dr Tseng and his colleagues presents an excellent example of the kind of contribution the Suite can make.”

As work on the replacement valves progresses, the team will also start looking for commercial partners to help them in the later stages of clinical trials. “That requires a different kind of expertise, which we don’t have in academia.”

While the focus at present is replacement heart valves, the approach could have many other applications. “Once you have the scaffold, it becomes a platform technology that you can use to engineer other tissues,” says Dr Tseng. Possibilities include addressing vascular conditions, such as repairing blood vessels damaged in dialysis, and building cardiac patches to repair damage to the heart.

*Yacoub, MH, Tseng, YT, Kluin, J et al. Valvulogenesis of a living, innervated pulmonary root induced by an acellular scaffold. Communications Biology 6, 1017 (2023). https://doi.org/10.1038/s42003-023-05383-z