Tissue Engineering Therapy Research Articles

Heat Transfer of Casson Fluid in Poiseuille Flow of Carbon Nanotubes: A Power Series Approach

Combination of Carbon Nanotubes (CNTs) with Human blood as base fluid indicates the enhancement of heat transport in Poiseuille flow and this physical phenomenon could not possible in normal liquids. Usually, when blood cells get touch with external surfaces, the platelets of blood become activated and form blood clots. Therefore, we have considered blood compatible CNT, so that chosen base fluid (blood) can easily pass through it. Due to the higher thermal conductivity, CNTs play an important role to enhance the heat transport in blood flow. These features lead to the novelty of this investigation to study the heat transport of Casson fluid through CNTs in unsteady MHD free convective Poiseuille flow with thermal radiation. Such study consigns practical applications in manufacturing of drugs, biomedical and Tissue engineering, biosensor and other applications in myocardial therapy, neuronal and muscle regeneration. The non-dimensional governing equations are formulated and solved analytically through classical Perturbation Technique and the analysis of results are drawn in smooth curves via MATLAB code. Significant results for different implanted parameters are compared between SWCNT and MWCNT and their significant behaviours are plotted graphically. The obtained results indicate that Casson parameter accelerates the flow velocity for MWCNT and SWCNT. Furthermore, interesting behavior on the outlines of velocity for SWCNT and MWCNT due to the presence of Schmidt number, Peclet number and Reynolds number are detected. Comparison with previously published work has been inspected and originated excellent agreement.

Fascia Promotes Adipose Tissue Regeneration by Improving Early Macrophage Infiltration after Fat Grafting in a Mouse Model.

Low early macrophage fat graft infiltration (within a week of surgery) hinders tissue regeneration, suggesting that macrophages play a vital role in early angiogenesis and adipogenesis. However, the source of macrophages during this period is unclear. C57BL/6 mice were split into fascial removal (FR) group and control groups (CG). Mice had a piece of back fascia removed in the FR group, which was immediately replaced in the CG, and inguinal fat injected into the transplantation site of both groups. Separately, fascia was harvested from green fluorescent protein-expressing mice and transplanted into C57BL/6 mice for tracing macrophage infiltration after fat grafting. The number of capillaries in the FR group was lower than that in the CG at days 3 ( P < 0.01) and 7 ( P < 0.05). Moreover, the number of small adipocytes in the FR group was lower than in the CG on days 3, 7, and 14 (all P < 0.05), and the relative expression of several adipogenic proteins was significantly lower in the FR group than in the CG on days 14 and 30. The timeline of macrophage infiltration was consistent with angiogenesis and adipogenesis. The number of macrophages in the FR group was significantly lower than in the CG at days 3 and 7 ( P < 0.05), and there were more fascia-derived macrophages than circulation-derived macrophages infiltrated into fat grafts within 7 days. Finally, the graft retention was lower in the FR group than the CG at day 90 ( P < 0.05). In the early stage after fat grafting, fascial macrophage infiltration initiates tissue regeneration, thereby improving graft retention by promoting angiogenesis and adipogenesis. In the clinic, injecting fat close to the fascia may increase fat retention. Fascia is widespread and self-regenerating, which may be a promising alternative source of local macrophages, with implications for tissue-engineering therapies such as correction of soft-tissue defects and breast reconstruction.

A Case for Material Stiffness as a Design Parameter in Encapsulated Islet Transplantation.

Diabetes is a disease that plagues over 463 million people globally. Approximately 40 million of these patients have type 1 diabetes mellitus (T1DM), and the global incidence is increasing by up to 5% per year. T1DM is where the body's immune system attacks the pancreas, specifically the pancreatic beta cells, with antibodies to prevent insulin production. Although current treatments such as exogenous insulin injections have been successful, exorbitant insulin costs and meticulous administration present the need for alternative long-term solutions to glucose dysregulation caused by diabetes. Encapsulated islet transplantation (EIT) is a tissue-engineered solution to diabetes. Donor islets are encapsulated in a semipermeable hydrogel, allowing the diffusion of oxygen, glucose, and insulin but preventing leukocyte infiltration and antibody access to the transplanted cells. Although successful in small animal models, EIT is still far from commercial use owing to necessary long-term systemic immunosuppressants and consistent immune rejection. Most published research has focused on tailoring the characteristics of the capsule material to promote clinical viability. However, most studies have been limited in scope to biochemical changes. Current mechanobiology studies on the effect of substrate stiffness on the function of leukocytes, especially macrophages-primary foreign body response (FBR) orchestrators, show promise in tailoring a favorable response to tissue-engineered therapies such as EIT. In this review, we explore strategies to improve the clinical viability of EIT. A brief overview of the immune system, the FBR, and current biochemical approaches will be elucidated throughout this exploration. Furthermore, an argument for using substrate stiffness as a capsule design parameter to increase EIT efficacy and clinical viability will be posed.

Development of magnetic poly(L-lactic Acid) nanofibrous microspheres for transporting and delivering targeted cells

To avoid infection and other risks caused by large open-surgery incisions using scaffold transplants, it is very important to study injectable microcarrier-loaded cells for targeted therapy and tissue regeneration. In this study, on the one hand, to simulate the hierarchical structure of the extracellular matrix and carry cells, poly(L-lactic acid) (PLLA) nanofibrous microspheres (large microspheres) were initially fabricated as cell carriers. On the other hand, to precisely deliver cells through a magnetic field and promote stem cell differentiation, drug-loaded mesoporous Fe3O4@SiO2 microspheres (small microspheres) were prepared and coated on the surface PLLA nanofibrous microspheres. The coating conditions were systematically studied and optimized. The results showed that planetary-satellite-like cell carriers were successfully prepared and the carriers were capable of freely translocating under the influence of a magnetic field. It has been demonstrated in vitro experiments that the carriers are biocompatible and are capable of acting as drug carriers. Specifically, they were able to load and release cells in response to magnetic fields. In vivo experiments indicated that the carriers could successfully load and release GFP-labelled cells in nude mice. The study presented in this paper provides a versatile and promising platform for the cell-based therapy in tissue engineering and regenerative medicine.

Minimal invasiveness in vertical ridge augmentation.

Vertical ridge augmentation is one of the most challenging procedures in implant dentistry because of the advanced skills required by the operator and the fact that bone augmentation is aimed outside the bony contour, in an environment of reduced blood supply. What is more, the flap management required to ensure soft tissue closure frequently leads to associated comorbidities in terms of swelling and hematomas. For these reasons, and even if autologous onlay block grafts are still the gold standard, new techniques and biomaterials have favored the development of potentially less invasive approaches. The present work evaluates the most recent strategies in vertical ridge augmentation to reduce invasiveness and complications, including diagnostic/treatment planning considerations, surgical techniques, digital tools (eg, customized titanium meshes/membranes or bone blocks), and future trends in the field of tissue engineering and cell therapy.

Design and development of biodegradable POSS-PCL-Zeolite (β) nano-scaffold for potential applications in bone regeneration

Side effects caused by bone fractures and restrictions on bone regeneration impose an enormous economic burden on the health system of society. To overcome these limitations, tissue engineering and cell-based therapies have been proposed as alternatives to induce and promote bone healing. Still, bone regeneration disadvantages, such as limited and painful surgery, the risk of infection, nerve injury, bleeding, and function damage, have led investigators to find an alternative therapy. In some studies, bone stimulants have prompted scientists to design scaffolds with appropriate physical structure with the possibility of cell adhesion and proliferation, which plays an influential role in the regeneration and repair of bone tissue. PCL nanofiber is an absorbing candidate for the formulation of biocompatible scaffolds used in tissue engineering. To overcome these negative aspects, improve the properties of PCL nanofibers, and based on the biocompatibility and superior mechanical properties of POSS, Polyhedral Oligomeric Silsesquioxane-Polycaprolactone-Zeolite (POSS-PCL-Zeolite) nanocomposite electrospun nanofiber scaffolds were fabricated in the present study. Nanohybrids and nanofibers structures were characterized by FTIR, HNMR, XRD, SEM, EDX, and DSC techniques. We used cellular and molecular assays, including DCFH ROS detection system, gene expression (RUNX-2, Osteocalcin, Nrf2, BAX, VEGF gens), and apoptotic to demonstrate the biocompatibility and induce bone differentiation of formulated POSS-PCL-Zeolite scaffolds. The results showed the biodegradability of POSS-PCL-Zeolite Nano-scaffold and supported the nesting of mesenchymal stem cells (MSCs) and induced bone differentiation by POSS-PCL-Zeolite Nano-scaffold.

Engineered elastin-like polypeptides: An efficient platform for enhanced cancer treatment.

Drug delivery systems (DDSs) have recently gained widespread attention for improving drug loading and delivery efficiency in treating many cancers. Elastin-like polypeptides (ELPs) are synthetic peptides derived from a precursor of elastin (tropoelastin), reserving similar structural and physicochemical properties. ELPs have gained a variety of applications in tissue engineering and cancer therapy due to their excellent biocompatibility, complete degradability, temperature-responsive property, controllable sequence and length, and precisely tuned structure and function. ELPs-based drug delivery systems can improve the pharmacokinetics and biodistribution of therapeutic reagents, leading to enhanced antitumor efficacy. In this review, we summarize the recent application of ELPs in cancer treatment, focusing on the delivery of functional peptides, therapeutic proteins, small molecule drugs, and photosensitizers.

Method for manufacture and cryopreservation of cartilage microtissues

The financial viability of a cell and tissue-engineered therapy may depend on the compatibility of the therapy with mass production and cryopreservation. Herein, we developed a method for the mass production and cryopreservation of 3D cartilage microtissues. Cartilage microtissues were assembled from either 5000 human bone marrow-derived stromal cells (BMSC) or 5000 human articular chondrocytes (ACh) each using a customized microwell platform (the Microwell-mesh). Microtissues rapidly accumulate homogenous cartilage-like extracellular matrix (ECM), making them potentially useful building blocks for cartilage defect repair. Cartilage microtissues were cultured for 5 or 10 days and then cryopreserved in 90% serum plus 10% dimethylsulfoxide (DMSO) or commercial serum-free cryopreservation media. Cell viability was maximized during thawing by incremental dilution of serum to reduce oncotic shock, followed by washing and further culture in serum-free medium. When assessed with live/dead viability dyes, thawed microtissues demonstrated high viability but reduced immediate metabolic activity relative to unfrozen control microtissues. To further assess the functionality of the freeze-thawed microtissues, their capacity to amalgamate into a continuous tissue was assess over a 14 day culture. The amalgamation of microtissues cultured for 5 days was superior to those that had been cultured for 10 days. Critically, the capacity of cryopreserved microtissues to amalgamate into a continuous tissue in a subsequent 14-day culture was not compromised, suggesting that cryopreserved microtissues could amalgamate within a cartilage defect site. The quality ECM was superior when amalgamation was performed in a 2% O2 atmosphere than a 20% O2 atmosphere, suggesting that this process may benefit from the limited oxygen microenvironment within a joint. In summary, cryopreservation of cartilage microtissues is a viable option, and this manipulation can be performed without compromising tissue function.

Efficient Differentiation of Human Induced Pluripotent Stem Cell (hiPSC)-Derived Mesenchymal Progenitors Into Adipocytes and Osteoblasts.

Human induced pluripotent stem cells (hiPSCs) hold immense promise in regenerative medicine as they can differentiate into various cell lineages, including adipocytes, osteoblasts, and chondrocytes. Precisely guiding hiPSC-derived mesenchymal progenitor cells (iMSCs) towards specific differentiation pathways is crucial for harnessing their therapeutic potential in tissue engineering, disease modeling, and regenerative therapies. To achieve this, we present a comprehensive and reproducible protocol for effectively differentiating iMSCs into adipocytes and osteoblasts. The differentiation process entails culturing iMSCs in tailored media supplemented with specific growth factors, which act as cues to initiate adipogenic or osteogenic commitment. Our protocol provides step-by-step guidelines for achieving adipocyte and osteoblast differentiation, ensuring the generation of mature and functional cells. To validate the success of differentiation, key assessment criteria are employed. For adipogenesis, the presence of characteristic lipid droplets within the iMSC-derived cells is considered indicative of successful differentiation. Meanwhile, Alizarin Red staining serves as a marker for the osteogenic differentiation, confirming the formation of mineralized nodules. Importantly, the described method stands out due to its simplicity, eliminating the need for specialized equipment, expensive materials, or complex reagents. Its ease of implementation offers an attractive advantage for researchers seeking robust and cost-effective approaches to derive adipocytes and osteoblasts from iMSCs. Overall, this protocol establishes a foundation for exploring the therapeutic potential of hiPSC-derived cells and advancing the field of regenerative medicine. Key features • iMSC derivation in this protocol uses embryonic body formation technique. • Adipogenesis and osteogenesis protocols were optimized for human iPSC-derived iMSCs. • Derivation of iMSC from hiPSC was developed in a feeder-free culture condition. • This protocol does not include human iPSC reprogramming strategies.

How Much Do We Know About the Mouse Respiratory Epithelial Stem Cells?

Background-Purpose of this study: Tissue-specific stem cell lines are useful tools for cell biology studies. Information on respiratory tissue cell lines is limited. A doxycycline-regulated epithelial precursor cell line was established from the lung tissue of a tTAxSV40 Tag double transgenic mouse. In this study, we have characterized this cell line in vitro &amp; in vivo, and found to mimic a rare subpopulation of club- and pneumocyte type II-dual cells. Methods: It was partially characterized using cell viability and death assays, H3-thymidine incorporation assay, chloride efflux assay, Western blotting of proteins secreted, RT-PCR assays for RNA isolated. In addition, immune-deficient SCID mice were used as hosts for implantation of this precursor cell line, and feed with/without doxycycline containing water. Immunofluorescent typing using different antibodies were used to characterize the implanted lung. Results: This cell line was found to mimic a rare subpopulation of club- and pneumocyte type II- dual cells with multiple phenotypes. Cell growth was doxycycline-regulated and observed only when doxycycline was omitted from the medium or present at concentrations up to 1 µg/ml, higher concentrations were inhibitory. ACT+ ciliated cells were found upon implantation into immune-deficient mice, in addition. Cell growth was doxycycline-regulated in vitro. When transplanted subcutaneously into immune-deficient mice, these cells migrated to the lung to form organized chimeric structures of donor and host origins, with club cells in the terminal bronchioles, ACT+ ciliated cells along the epithelial lining, and pneumocyte type II-cells in the alveolar interstices. No such homing of donor cells to the lung was observed when the implanted mice were fed doxycycline-containing water. Discussions-Conclusions: This lung stem cell line might be able to provide us with an insight into the differentiation pathway of lung epithelial cells as well as with some understanding of the nature of air trophic-pulmonary epithelial cells. The results of this study underline the possibility of a future application for somatic (stem / precursor) cells in tissue replacement and tissue engineering of the damaged lung. Its ability to secrete and deliver soluble protein, might be a potential novel way for drug delivery. In addition, stem cells are thought to proliferate and differentiate in response to a deficiency or as a result of injury. Successful migration to the target organ and subsequent maturation of these precursors could be attributed to a requirement of lung stem cells to search for an aerated environment. Our findings challenge some current concepts of stem cell biology.This lung stem cell line may become a rich source of cells for tissue engineering and cell-based therapy for lung injury. The route and protocol established for cell introduction into the lung may provide a novel alternative to delivery of soluble protein substances through the airways. This lung stem cell line might also be modified to provide models for screening drugs against respiratory infection.

Dynamic changes in mechanical properties of the adult rat spinal cord after injury.

Spinal cord injury (SCI), a debilitating medical condition that can cause irreversible loss of neurons and permanent paralysis, currently has no cure. However, regenerative medicine may offer a promising treatment. Given that numerous regenerative strategies aim to deliver cells and materials in the form of tissue-engineered therapies, understanding and characterising the mechanical properties of the spinal cord tissue is very important. In this study, we have systematically characterised the spatiotemporal changes in elastic stiffness (elastic modulus, Pa) and viscosity (drop in peak force, %) of injured rat thoracic spinal cord tissues at distinct time points after crush injury using the indentation technique. Our results demonstrate that in comparison with uninjured spinal cord tissue, the injured tissues exhibited lower stiffness (median 3281 Pa versus 9632 Pa; P<0.001) but demonstrated elevated viscosity (median 80% versus 57%; P<0.001) at 3 days postinjury. Between 4 and 6 weeks after SCI, the overall viscoelastic properties of injured tissues returned to baseline values. At 12 weeks after SCI, in comparison with uninjured tissue, the injured spinal cord tissues displayed a significant increase in both elasticity (median 13698 Pa versus 9920 Pa; P<0.001) and viscosity (median 64% versus 58%; P<0.001). This work constitutes the first quantitative mapping of spatiotemporal changes in spinal cord tissue elasticity and viscosity in injured rats, providing a mechanical basis of the tissue for future studies on the development of biomaterials for SCI repair. STATEMENT OF SIGNIFICANCE: Spinal cord injury (SCI) is a devastating disease often leading to permanent paralysis. While enormous progress in understanding the molecular pathomechanisms of SCI has been made, the mechanical properties of injured spinal cord tissue have received considerably less attention. This study provides systematic characterization of the biomechanical evolution of rat spinal cord tissue after SCI using a microindentation test method. We find spinal cord tissue behaves significantly softer but more viscous immediately postinjury. As time passes, the lesion site gradually returns to baseline values and then displays pronounced increased viscoelastic properties. As host tissue mechanical properties are a crucial consideration for any biomaterial implanted into central nervous system, our results may have important implications for further studies of SCI repair.

Carbon Nanostructures as Therapeutic Cargoes: Recent Developments and Challenges

Recent developments in nanotechnology and process chemistry have expanded the scope of nanostructures to the biomedical field. The ability of nanostructures to precisely deliver drugs to the target site not only reduces the amount of drug needed but also reduces systemic adverse effects. Carbon nanostructures gained traction in pharmaceutical technology in the last decade due to their high stability, ease of synthesis, tunable surface chemistry, and biocompatibility. Fullerene, nanotubes, nanodiamonds, nanodots, and nanoribbons are among the major carbon nanostructures that have been extensively studied for applications in tissue engineering, biosensing, bioimaging, theranostics, drug delivery, and gene therapy. Due to the fluorescent properties of functionalized nanostructures, they have been extensively studied for use as probes in cellular imaging. Moreover, these nanostructures are promising candidates for delivering drugs to the brain, bones, and deep-seated tumors. Still, research gaps need to be addressed regarding the toxicity of these materials in animals as well as humans. This review highlights the physicochemical properties of carbon nanostructures and their categories, methods of synthesis, various techniques for surface functionalization, major biomedical applications, mechanisms involving the cellular uptake of nanostructures, pharmacokinetic considerations, recent patents involving carbon-based nanostructures in the biomedical field, major challenges, and future perspectives.

Efficient bone regeneration of BMP9-stimulated human periodontal ligament stem cells (hPDLSCs) in decellularized bone matrix (DBM) constructs to model maxillofacial intrabony defect repair

BackgroundBMP9-stimulated DPSCs, SCAPs and PDLSCs are effective candidates for repairing maxillofacial bone defects in tissue engineering, while the most suitable seed cell source among these three hDMSCs and the optimal combination of most suitable type of hDMSCs and BMP9 have rarely been explored. Moreover, the orthotopic maxillofacial bone defect model should be valuable but laborious and time-consuming to evaluate various candidates for bone regeneration. Thus, inspired from the maxillofacial bone defects and the traditional in vivo ectopic systems, we developed an intrabony defect repair model to recapitulate the healing events of orthotopic maxillofacial bone defect repair and further explore the optimized combinations of most suitable hDMSCs and BMP9 for bone defect repair based on this modified ectopic system.MethodsIntrabony defect repair model was developed by using decellularized bone matrix (DBM) constructs prepared from the cancellous part of porcine lumbar vertebral body. We implanted DBM constructs subcutaneously on the flank of each male NU/NU athymic nude mouse, followed by directly injecting the cell suspension of different combinations of hDMSCs and BMP9 into the central hollow area of the constructs 7 days later. Then, the quality of the bony mass, including bone volume fraction (BV/TV), radiographic density (in Hounsfield units (HU)) and the height of newly formed bone, was measured by micro-CT. Furthermore, the H&E staining and immunohistochemical staining were performed to exam new bone and new blood vessel formation in DBM constructs.ResultsBMP9-stimulated periodontal ligament stem cells (PDLSCs) exhibited the most effective bone regeneration among the three types of hDMSCs in DBM constructs. Furthermore, an optimal dose of PDLSCs with a specific extent of BMP9 stimulation was confirmed for efficacious new bone and new blood vessel formation in DBM constructs.ConclusionsThe reported intrabony defect repair model can be used to identify optimized combinations of suitable seed cells and biological factors for bone defect repair and subsequent development of efficacious bone tissue engineering therapies.

A Novel Perspective on Tissue Engineering Potentials of Periodontal Ligament Stem Cells

It is challenging to completely and predictably regenerate the missing periodontal tissues caused by the trauma or disease. To regenerate the periodontium, there is a need to consider several aspects that co-occur with periodontal development. This study provides an overview of the most up-to-date investigations on the characteristics and immunomodulatory features of Periodontal Ligament Stem Cells (PDLSCs) and the recent interventions performed using these cells, focusing on cell survival, proliferation, and differentiation. Keeping in mind the relationship between age and potency of PDLSCs, this work also demonstrates the necessity of establishing dental-derived stem cell banks for tissue regeneration applications. The data were collected from Pubmed and Google Scholar databases with the keywords of periodontal ligament stem cells, tissue engineering, characteristics, and stem cell therapy. The results showed the presence of wide-ranging research reports supporting the usability of PDLSCs for periodontal reconstruction. However, a better understanding of self-restoration for adequate regulation of adult stem cell growth is needed for various applied purposes.

Laser-Structured Si and PLGA Inhibit the Neuro2a Differentiation in Mono- and Co-Culture with Glia

Background:The first step towards a successful neural tissue engineering therapy is the development of an appropriate scaffold and the in vitro study of the cellular response onto it.Methods:Here, we fabricated nano- and micro- patterned Si surfaces via direct ultrafast laser irradiation, as well as their replicas in the biodegradable poly(lactide-co-glycolide), in order to use them as culture substrates for neuronal cells. The differentiation of neuro2a cells on the Si platforms and their replicas was studied both in a mono-culture and in a co-culture with glial cells (Schwann—SW10).Results:It was found that the substrate’s roughness inhibits the differentiation of the neuronal cells even in the presence of the differentiation medium, and the higher the roughness is, the more the differentiation gets limited.Conclusion:Our results highlight the importance of the substrate’s topography for the controlled growth and differentiation of the neuronal cells and their further study via protein screening methods could shed light on the factors that lead to limited differentiation; thus, contributing to the long standing request for culture substrates that induce cells to differentiate.

Differentiation of Human Adipose-Derived Mesenchymal Stromal/Stem Cells into Insulin-Producing Cells with A Single Tet-Off Lentiviral Vector System.

Human adipose-derived mesenchymal stromal/stem cells (hASC) constitute an attractive source of stem cells for cell-based therapies in regenerative medicine and tissue engineering as they are easy to acquire from lipoaspirate, expansion, and genetic modification ex vivo. The combination of Pdx-1, MafA, and NeuroD1 has been indicated to possess the ability to reprogram various types of cells into insulin-producing cells. The aim of this study is to investigate whether MafA and NeuroD1 would cooperate with Pdx-1 in the differentiation of hASC into insulin-producing cells. In this experimental study, we generated polycistronic expression vectors expressing Pdx1 and MafA/NeuroD1 with a reporter from a human EF-1α promoter using 2A peptides in a single tet-off lentiviral vector system. Briefly, hASC were transduced with the lentiviral vectors and allowed to differentiate into insulin-producing cells in vitro and in vivo. Thereafter, RNA expression, dithizone staining, and immunofluorescent analysis were conducted. Cleaved transcriptional factors from a single tet-off lentiviral vector were functionally equivalent to their native proteins and strictly regulated by doxycycline (Dox). Insulin gene expression in hASC transduced with Pdx1, Pdx1/ MafA, and Pdx1/NeuroD1 in differentiation medium were successfully increased by 1.89 ± 0.39, 4.81 ± 0.98, 5.51 ± 0.63, respectively, compared to venus-transduced, control hASC. These cells could form dithizone-positive cell clusters in vitro and were found to express insulin in vivo. Using our single tet-off lentiviral vector system, Pdx-1 and MafA/NeuroD1 could be simultaneously expressed in the absence of Dox. Further, this system allowed the differentiation of hASC into insulin-producing cells.

Regenerative medicine applications: An overview of clinical trials.

Insights into the use of cellular therapeutics, extracellular vesicles (EVs), and tissue engineering strategies for regenerative medicine applications are continually emerging with a focus on personalized, patient-specific treatments. Multiple pre-clinical and clinical trials have demonstrated the strong potential of cellular therapies, such as stem cells, immune cells, and EVs, to modulate inflammatory immune responses and promote neoangiogenic regeneration in diseased organs, damaged grafts, and inflammatory diseases, including COVID-19. Over 5,000 registered clinical trials on ClinicalTrials.gov involve stem cell therapies across various organs such as lung, kidney, heart, and liver, among other applications. A vast majority of stem cell clinical trials have been focused on these therapies' safety and effectiveness. Advances in our understanding of stem cell heterogeneity, dosage specificity, and ex vivo manipulation of stem cell activity have shed light on the potential benefits of cellular therapies and supported expansion into clinical indications such as optimizing organ preservation before transplantation. Standardization of manufacturing protocols of tissue-engineered grafts is a critical first step towards the ultimate goal of whole organ engineering. Although various challenges and uncertainties are present in applying cellular and tissue engineering therapies, these fields' prospect remains promising for customized patient-specific treatments. Here we will review novel regenerative medicine applications involving cellular therapies, EVs, and tissue-engineered constructs currently investigated in the clinic to mitigate diseases and possible use of cellular therapeutics for solid organ transplantation. We will discuss how these strategies may help advance the therapeutic potential of regenerative and transplant medicine.

Chlorogenic Acid Fractionation in Robusta Green Bean Extract as a Combination Agent of Dental Pulp Stem Cells in Periodontal Tissue Engineering

Background: Robusta coffee beans contain very high chlorogenic acid. In the last decade, chlorogenic acid was developed as an adjunct in stem cells to enhance the anti-inflammatory and antioxidant properties of stem cells when used as a therapeutic agent. Chlorogenic acid can increase proliferation and migration and inhibit the production of pro-inflammatory cytokines in stem cells thereby increasing the ability of stem cells to regenerate tissue. Purpose: To analyze the levels of chlorogenic acid in robusta coffee bean extract which can be used as a combination agent for Dental Pulp Stem Cells (DPSC) in periodontal tissue engineering therapy. Materials and Methods: Robusta coffee bean extract was obtained from the Coffee and Cocoa Research Center, Jember Regency which was processed and processed using the fractionation method. This study used DPSC with the extraction of premolar teeth of orthodontic patients. The toxicity test was performed on the coffee extract 0.0625%; 0.125%; 0.25%; 0.5% to determine the biocompatible concentration of DPSC. Results: The highest fractionation and measurement of chlorogenic acid content obtained was 30.49%. Robusta coffee bean extract with a chlorogenic acid content of 30.49% at concentrations of 0.125% and 0.0625% did not cause toxicity to DPSC. Conclusion: Chlorogenic acid in robusta coffee bean extract concentrations of 0.125% and 0.0625% are relatively biocompatible as a combination agent for DPSC in periodontal tissue engineering therapy.

Within or Without You? A Perspective Comparing In Situ and Ex Situ Tissue Engineering Strategies for Articular Cartilage Repair.

Human articular cartilage has a poor ability to self-repair, meaning small injuries often lead to osteoarthritis, a painful and debilitating condition which is a major contributor to the global burden of disease. Existing clinical strategies generally do not regenerate hyaline type cartilage, motivating research toward tissue engineering solutions. Prospective cartilage tissue engineering therapies can be placed into two broad categories: i) Ex situ strategies, where cartilage tissue constructs are engineered in the lab prior to implantation and ii) in situ strategies, where cells and/or a bioscaffold are delivered to the defect site to stimulate chondral repair directly. While commonalities exist between these two approaches, the core point of distinction-whether chondrogenesis primarily occurs "within" or "without" (outside) the body-can dictate many aspects of the treatment. This difference influences decisions around cell selection, the biomaterials formulation and the surgical implantation procedure, the processes of tissue integration and maturation, as well as, the prospects for regulatory clearance and clinical translation. Here, ex situ and in situ cartilage engineering strategies are compared: Highlighting their respective challenges, opportunities, and prospects on their translational pathways toward long term human cartilage repair.

The Future of Targeted Treatment of Primary Sjögren's Syndrome: A Focus on Extra-Glandular Pathology.

Primary Sjögren's syndrome (pSS) is a chronic, systemic autoimmune disease defined by exocrine gland hypofunction resulting in dry eyes and dry mouth. Despite increasing interest in biological therapies for pSS, achieving FDA-approval has been challenging due to numerous complications in the trials. The current literature lacks insight into a molecular-target-based approach to the development of biological therapies. This review focuses on novel research in newly defined drug targets and the latest clinical trials for pSS treatment. A literature search was conducted on ClinicalTrials.gov using the search term "Primary Sjögren's syndrome". Articles published in English between 2000 and 2021 were included. Our findings revealed potential targets for pSS treatment in clinical trials and the most recent advances in understanding the molecular mechanisms underlying the pathogenesis of pSS. A prominent gap in current trials is in overlooking the treatment of extraglandular symptoms such as fatigue, depression, and anxiety, which are present in most patients with pSS. Based on dryness and these symptom-directed therapies, emerging biological agents targeting inflammatory cytokines, signal pathways, and immune reaction have been studied and their efficacy and safety have been proven. Novel therapies may complement existing non-pharmacological methods of alleviating symptoms of pSS. Better grading systems that add extraglandular symptoms to gauge disease activity and severity should be created. The future of pSS therapies may lie in gene, stem-cell, and tissue-engineering therapies.