An update on stem cell and stem cell-derived extracellular vesicle-based therapy in the management of Alzheimer's disease

Globally, neurological diseases pose a major burden to healthcare professionals in terms of the management and prevention of the disorder. Among neurological diseases, Alzheimer's disease (AD) accounts for 50%-70% of dementia and is the fifth leading cause of mortality worldwide. AD is a progressive, degenerative neurological disease, with the loss of neurons and synapses in the cerebral cortex and subcortical regions. The management of AD remains a debate among physicians as no standard and specific "disease-modifying" modality is available. The concept of 'Regenerative Medicine' is aimed at regenerating the degenerated neural tissues to reverse the pathology in AD. Genetically modified engineered stem cells modify the course of AD after transplantation into the brain. Extracellular vesicles (EVs) are an emerging new approach in cell communication that involves the transfer of cellular materials from parental cells to recipient cells, resulting in changes at the molecular and signaling levels in the recipient cells. EVs are a type of vesicle that can be transported between cells. Many have proposed that EVs produced from mesenchymal stem cells (MSCs) may have therapeutic promise in the treatment of AD. The biology of AD, as well as the potential applications of stem cells and their derived EVs-based therapy, were explored in this paper.

Mesenchymal stromal cell therapy for patients with rheumatoid arthritis

Management of relapses and refractory rheumatoid arthritis (RA) patients is complex and difficult. Even after the administration of new biological disease-modifying anti-rheumatic drugs (DMARDs), only a few patients achieve the complete remission phase. DMARDs help only in modifying the disease activity, which sooner or later fails. They do not manage the disease at the patho-etiological level. There are some serious side effects as well as drug interaction with DMARDs. There are few subsets of RA patients who do not respond to DMARDs, reasons unknown. Mesenchymal stem cells (MSCs) provide a promising alternative, especially in such cases. This review elaborates on the studies pertaining to the application of MSCs in rheumatoid arthritis over the last two decades. A total of 14 studies (one review article) including 447 patients were included in the study. Most of the studies administered MSCs in refractory RA patients through the intravenous route with varied dosages and frequency of administration. MSCs help in RA treatment via various mechanisms including paracrine effects. All the studies depicted a better clinical outcome with minimal adverse events. The functional scores including the VAS scores improved significantly in all studies irrespective of dosage and source of MSCs. The majority of the studies depicted no complications. Although the use of MSCs in RA is still in the early stages requiring further refinement in the source of MSCs, dosage, and frequency. The role of MSCs in the management of RA has a promising prospect. MSCs target the RA at the molecular level and has the potential to manage refractory RA cases not responding to conventional treatment. Multicentric, large sample populations, and long-term studies are required to ascertain efficacy and safety.

Comparative effectiveness of adipose-derived mesenchymal stromal cells in the management of knee osteoarthritis: A meta-analysis

BACKGROUND

Osteoarthritis (OA) is the most common joint disorder, is associated with an increasing socioeconomic impact owing to the ageing population.

AIM

To analyze and compare the efficacy and safety of bone-marrow-derived mesenchymal stromal cells (BM-MSCs) and adipose tissue-derived MSCs (AD-MSCs) in knee OA management from published randomized controlled trials (RCTs).

METHODS

Independent and duplicate electronic database searches were performed, including PubMed, EMBASE, Web of Science, and Cochrane Library, until August 2021 for RCTs that analyzed the efficacy and safety of AD-MSCs and BM-MSCs in the management of knee OA. The visual analog scale (VAS) score for pain, Western Ontario McMaster Universities Osteoarthritis Index (WOMAC), Lysholm score, Tegner score, magnetic resonance observation of cartilage repair tissue score, knee osteoarthritis outcome score (KOOS), and adverse events were analyzed. Analysis was performed on the R-platform using OpenMeta (Analyst) software. Twenty-one studies, involving 936 patients, were included. Only one study compared the two MSC sources without patient randomization; hence, the results of all included studies from both sources were pooled, and a comparative critical analysis was performed.

RESULTS

At six months, both AD-MSCs and BM-MSCs showed significant VAS improvement (P = 0.015, P = 0.012); this was inconsistent at 1 year for BM-MSCs (P < 0.001, P = 0.539), and AD-MSCs outperformed BM-MSCs compared to controls in measures such as WOMAC (P < 0.001, P = 0.541), Lysholm scores (P = 0.006; P = 0.933), and KOOS (P = 0.002; P = 0.012). BM-MSC-related procedures caused significant adverse events (P = 0.003) compared to AD-MSCs (P = 0.673).

CONCLUSION

Adipose tissue is superior to bone marrow because of its safety and consistent efficacy in improving pain and functional outcomes. Future trials are urgently warranted to validate our findings and reach a consensus on the ideal source of MSCs for managing knee OA.

Current Role of Intra-Articular Injections of Platelet-Rich Plasma in Adhesive Capsulitis of Shoulder: A Systematic Review

Adhesive capsulitis shoulder is a common problem of patients presenting with shoulder pain and disability. The approach to such patients includes a variety of modalities. This systematic review evaluates the efficacy of intra-articular injections of platelet-rich plasma (PRP) in the treatment. A literature search was performed between January 2010 and 30 May 2022. MeSH terms used were 'Platelet-rich plasma' OR 'PRP' AND 'Frozen shoulder' OR 'Adhesive capsulitis shoulder' OR 'Periarthritis shoulder'. The search included published articles in the English language involving human subjects. Studies evaluating other types of shoulder disorders, in vitro studies, review articles, animal-model studies, and pre-clinical trials were excluded. The data regarding study characteristics, efficacy, and safety outcomes were analyzed. A total of 11 studies with 347 patients over 10 years were finally included in this review. Most publications were in 2019 and 2020, mostly from India. This review included seven comparative studies, three case series, and one case report. In seven studies, a single intra-articular PRP injection was administered, whereas in the rest of the studies two or multiple injections were given. Only one study demonstrated an equivocal efficacy of PRP and steroid intra-articular injection. The rest all depicted better clinical and functional outcomes with the PRP injection. Only one study compared the outcomes of hydro-dissection treatment in adhesive capsulitis with the intra-articular PRP injection. The rest all either examined PRP alone or compared it with the steroid intra-articular injection. None of the studies showed any major side effects. The intra-articular injections of PRP in the management of adhesive capsulitis of the shoulder provide a new treatment approach. Further studies are required to ascertain the efficacy and safety of the PRP intraarticular injection as a management alternative in adhesive capsulitis.

Current understanding of MSC-derived exosomes in the management of knee osteoarthritis

Mesenchymal stem cell-derived exosomes (MSC-Exos) have been utilized as medicinal agents or as delivery vehicles in cartilage injuries and cartilage-based diseases. Given the ongoing emergence of evidence on the effector mechanisms and methods of the utility of the MSC-Exos in knee osteoarthritis, a comprehensive review of the current evidence is the need of the hour. Hence, in this article, we review the current understanding of the role of MSC-Exos in the management of knee osteoarthritis in view of their classification, characterization, biogenesis, mechanism of action, pathways involved in their therapeutic action, in-vitro evidence on cartilage regeneration, in-vivo evidence in OA knee models and recent advances in using MSC-Exos to better streamline future research from bench to bedside for OA knee.

Application of extracellular vesicles from mesenchymal stem cells promotes hair growth by regulating human dermal cells and follicles

BACKGROUND

Dermal papillae (DP) and outer root sheath (ORS) cells play important roles in hair growth and regeneration by regulating the activity of hair follicle (HF) cells.

AIM

To investigate the effects of human mesenchymal stem cell-derived extracellular vesicles (hMSC-EVs) on DP and ORS cells as well as HFs. EVs are known to regulate various cellular functions. However, the effects of hMSC-EVs on hair growth, particularly on human-derived HF cells (DP and ORS cells), and the possible mechanisms underlying these effects are unknown.

METHODS

hMSC-EVs were isolated and characterized using transmission electron microscopy, nanoparticle tracking analysis, western blotting, and flow cytometry. The activation of DP and ORS cells was analyzed using cellular proliferation, migration, western blotting, and real-time polymerase chain reaction. HF growth was evaluated ex vivo using human HFs.

RESULTS

Wnt3a is present in a class of hMSC-EVs and associated with the EV membrane. hMSC-EVs promote the proliferation of DP and ORS cells. Moreover, they translocate β-catenin into the nucleus of DP cells by increasing the expression of β-catenin target transcription factors (Axin2, EP2 and LEF1) in DP cells. Treatment with hMSC-EVs also promoted the migration of ORS cells and enhanced the expression of keratin (K) differentiation markers (K6, K16, K17, and K75) in ORS cells. Furthermore, treatment with hMSC-EVs increases hair shaft elongation in cultured human HFs.

CONCLUSION

These findings suggest that hMSC-EVs are potential candidates for further preclinical and clinical studies on hair loss treatment.

CAR T-Cell-Based gene therapy for cancers: new perspectives, challenges, and clinical developments

Chimeric antigen receptor (CAR)-T cell therapy is a progressive new pillar in immune cell therapy for cancer. It has yielded remarkable clinical responses in patients with B-cell leukemia or lymphoma. Unfortunately, many challenges remain to be addressed to overcome its ineffectiveness in the treatment of other hematological and solidtumor malignancies. The major hurdles of CAR T-cell therapy are the associated severe life-threatening toxicities such as cytokine release syndrome and limited anti-tumor efficacy. In this review, we briefly discuss cancer immunotherapy and the genetic engineering of T cells and, In detail, the current innovations in CAR T-cell strategies to improve efficacy in treating solid tumors and hematologic malignancies. Furthermore, we also discuss the current challenges in CAR T-cell therapy and new CAR T-cell-derived nanovesicle therapy. Finally, strategies to overcome the current clinical challenges associated with CAR T-cell therapy are included as well.

Application of Sygen® in Diabetic Peripheral Neuropathies—A Review of Biological Interactions

This study investigates the role of Sygen^® in diabetic peripheral neuropathy, a severe disease that affects the peripheral nervous system in diabetic individuals. This disorder often impacts the lower limbs, causing significant discomfort and, if left untreated, progresses into more serious conditions involving chronic ulcers and even amputation in many cases. Although there are management strategies available, peripheral neuropathies are difficult to treat as they often present multiple causes, especially due to metabolic dysfunction in diabetic individuals. Gangliosides, however, have long been studied and appreciated for their role in neurological diseases. The monosialotetrahexosylganglioside (GM1) ganglioside, popularly known as Sygen, provides beneficial effects such as enhanced neuritic sprouting, neurotrophism, neuroprotection, anti-apoptosis, and anti-excitotoxic activity, being particularly useful in the treatment of neurological complications that arise from diabetes. This product mimics the roles displayed by neurotrophins, improving neuronal function and immunomodulation by attenuating exacerbated inflammation in neurons. Furthermore, Sygen assists in axonal stabilization and keeps nodal and paranodal regions of myelin fibers organized. This maintains an adequate propagation of action potentials and restores standard peripheral nerve function. Given the multifactorial nature of this complicated disorder, medical practitioners must carefully screen the patient to avoid confusion and misdiagnosis. There are several studies analyzing the role of Sygen in neurological disorders. However, the medical literature still needs more robust investigations such as randomized clinical trials regarding the administration of this compound for diabetic peripheral neuropathies, specifically.

Prebiotic Potential and Value-Added Products Derived from Spirulina laxissima SV001—A Step towards Healthy Living

Lately, microalgae-based value-added products have been gaining market value because they moderate the dependency on fossil fuel and high-value chemical products. To this end, the purpose of this study was to develop prebiotic products from the microalgae Spirulina sp. The microalgae were isolated from the fresh water and characterized at the molecular level. The dry biomass, chlorophyll content, phycocyanin, cytotoxicity and antimicrobial and antioxidant properties of the isolated strains were analyzed. Moreover, value-added products like Spirulina cake, chocolate, tea, vermicelli and Spirulina juice were made for a vulnerable population due to high nutritive value.

Targeting GLI1 Transcription Factor for Restoring Iodine Avidity with Redifferentiation in Radioactive-Iodine Refractory Thyroid Cancers

Simple Summary

Thyroid cancers have an excellent prognosis by standard therapy of surgery followed by radioactive-iodine therapy. However, metastatic thyroid cancers do not response to radioactive-iodine therapy by losing iodine avidity. Therefore, reversing iodine avidity to metastatic thyroid cancers gives a new chance of applying radioactive-iodine therapy to the cancers. In the current study, we found that GLI1 knockdown can revert iodine non-avid thyroid cancers to iodine avid cancers by increasing expression of thyroid-specific proteins. Restoration of iodine avidity in thyroid cancers makes the cancers sensitive to radioactive-iodine therapy again. Therefore, the GLI1 can be a potential therapeutic target of radioactive-iodine resistant thyroid cancers.

Abstract

Radioactive-iodine (RAI) therapy is the mainstay for patients with recurrent and metastatic thyroid cancer. However, many patients exhibit dedifferentiation characteristics along with lack of sodium iodide symporter (NIS) functionality, low expression of thyroid-specific proteins, and poor RAI uptake, leading to poor prognosis. Previous studies have demonstrated the effect of GLI family zinc finger 1 (GLI1) inhibition on tumor growth and apoptosis. In this study, we investigated the role of GLI1 in the context of redifferentiation and improvement in the efficacy of RAI therapy for thyroid cancer. We evaluated GLI1 expression in several thyroid cancer cell lines and selected TPC-1 and SW1736 cell lines showing the high expression of GLI. We performed GLI1 knockdown and evaluated the changes of thyroid-specific proteins expression, RAI uptake and I-131-mediated cytotoxicity. The effect of GANT61 (GLI1 inhibitor) on endogenous NIS expression was also assessed. Endogenous NIS expression upregulated by inhibiting GLI1, in addition, increased expression level in plasma membrane. Also, GLI1 knockdown increased expression of thyroid-specific proteins. Restoration of thyroid-specific proteins increased RAI uptake and I-131-mediated cytotoxic effect. Treatment with GANT61 also increased expression of endogenous NIS. Targeting GLI1 can be a potential strategy with redifferentiation for restoring RAI avidity in dedifferentiated thyroid cancers.

Lineage Differentiation Potential of Different Sources of Mesenchymal Stem Cells for Osteoarthritis Knee

Tissue engineering and regenerative medicine (TERM) have paved a way for treating musculoskeletal diseases in a minimally invasive manner. The regenerative medicine cocktail involves the usage of mesenchymal stem/stromal cells (MSCs), either uncultured or culture-expanded cells along with growth factors, cytokines, exosomes, and secretomes to provide a better regenerative milieu in degenerative diseases. The successful regeneration of cartilage depends on the selection of the appropriate source of MSCs, the quality, quantity, and frequency of MSCs to be injected, and the selection of the patient at an appropriate stage of the disease. However, confirmation on the most favorable source of MSCs remains uncertain to clinicians. The lack of knowledge in the current cellular treatment is uncertain in terms of how beneficial MSCs are in the long-term or short-term (resolution of pain) and improved quality of life. Whether MSCs treatments have any superiority, exists due to sources of MSCs utilized in their potential to objectively regenerate the cartilage at the target area. Many questions on source and condition remain unanswered. Hence, in this review, we discuss the lineage differentiation potentials of various sources of MSCs used in the management of knee osteoarthritis and emphasize the role of tissue engineering in cartilage regeneration.

Advancing Regenerative Cellular Therapies in Non-Scarring Alopecia

Alopecia or baldness is a common diagnosis in clinical practice. Alopecia can be scarring or non-scarring, diffuse or patchy. The most prevalent type of alopecia is non-scarring alopecia, with the majority of cases being androgenetic alopecia (AGA) or alopecia areata (AA). AGA is traditionally treated with minoxidil and finasteride, while AA is treated with immune modulators; however, both treatments have significant downsides. These drawbacks compel us to explore regenerative therapies that are relatively devoid of adverse effects. A thorough literature review was conducted to explore the existing proven and experimental regenerative treatment modalities in non-scarring alopecia. Multiple treatment options compelled us to classify them into growth factor-rich and stem cell-rich. The growth factor-rich group included platelet-rich plasma, stem cell-conditioned medium, exosomes and placental extract whereas adult stem cells (adipose-derived stem cell-nano fat and stromal vascular fraction; bone marrow stem cell and hair follicle stem cells) and perinatal stem cells (umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs), Wharton jelly-derived MSCs (WJ-MSCs), amniotic fluid-derived MSCs (AF-MSCs), and placental MSCs) were grouped into the stem cell-rich group. Because of its regenerative and proliferative capabilities, MSC lies at the heart of regenerative cellular treatment for hair restoration. A literature review revealed that both adult and perinatal MSCs are successful as a mesotherapy for hair regrowth. However, there is a lack of standardization in terms of preparation, dose, and route of administration. To better understand the source and mode of action of regenerative cellular therapies in hair restoration, we have proposed the "À La Mode Classification". In addition, available evidence-based cellular treatments for hair regrowth have been thoroughly described.

Application of Orthobiologics in Achilles Tendinopathy: A Review

Orthobiologics are biological materials that are intended for the regeneration of bone, cartilage, and soft tissues. In this review, we discuss the application of orthobiologics in Achilles tendinopathy, more specifically. We explain the concepts and definitions of each orthobiologic and the literature regarding its use in tendon disorders. The biological potential of these materials can be harnessed and administered into injured tissues, particularly in areas where standard healing is disrupted, a typical feature of Achilles tendinopathy. These products contain a wide variety of cell populations, cytokines, and growth factors, which have been shown to modulate many other cells at local and distal sites in the body. Collectively, they can shift the state of escalated inflammation and degeneration to reestablish tissue homeostasis. The typical features of Achilles tendinopathy are failed healing responses, persistent inflammation, and predominant catabolic reactions. Therefore, the application of orthobiologic tools represents a viable solution, considering their demonstrated efficacy, safety, and relatively easy manipulation. Perhaps a synergistic approach regarding the combination of these orthobiologics may promote more significant clinical outcomes rather than individual application. Although numerous optimistic results have been registered in the literature, additional studies and clinical trials are still highly desired to further illuminate the clinical utility and efficacy of these therapeutic strategies in the management of tendinopathies.

Evolution of Mesenchymal Stem Cell Therapy as an Advanced Therapeutic Medicinal Product (ATMP)-An Indian Perspective

Stem cells can be defined as the cells that have the capacity to both self-renew and give rise to differentiated cells. Under the right conditions and signals, depending on their origin and bio-plasticity, stem cells can differentiate into multiple cell lineages and develop into various mature cells. Stem cell therapy is a fast-developing branch of medicine that includes the most innovative regenerative therapies for the restoration of cell and tissue function in individuals with severe diseases. Stem cell research has resulted in the emergence of cell-based therapies for disorders that are resistant to conventional drugs and therapies, and they are considered under the category of an Advanced Therapeutic Medicinal Product (ATMP). The FDA and the European Medicines Agency (EMA) devised a new strategy in 2017 with the aim of unifying the standards for development of ATMPs such that it is easy to exchange information at the international level. In this review, we discuss the evolution of mesenchymal stem cell-based therapy as an ATMP in the global and Indian scenarios, along with the guidelines governing their usage and clinical application of these therapeutics.

Impact of the Process Variables on the Yield of Mesenchymal Stromal Cells from Bone Marrow Aspirate Concentrate

Human bone marrow (BM) has been highlighted as a promising source of mesenchymal stromal cells (MSCs) containing various growth factors and cytokines that can be potentially utilized in regenerative procedures involving cartilage and bone. However, the proportion of MSCs in the nucleated cell population of BM is only around 0.001% to 0.01% thereby making the harvesting and processing technique crucial for obtaining optimal results upon its use in various regenerative processes. Although several studies in the literature have given encouraging results on the utility of BM aspiration concentrate (BMAC) in various regenerative procedures, there is a lack of consensus concerning the harvesting variables such as choice of anesthetic agent to be used, site of harvest, size of the syringe to be used, anticoagulant of choice, and processing variables such as centrifugation time, and speed. In this review article, we aim to discuss the variables in the harvesting and processing technique of BMAC and their impact on the yield of MSCs in the final concentrate obtained from them.

An Update on the Effectiveness of Probiotics in the Prevention and Treatment of Cancer

Probiotics are living microbes that play a significant role in protecting the host in various ways. Gut microbiota is one of the key players in maintaining homeostasis. Cancer is considered one of the most significant causes of death worldwide. Although cancer treatment has received much attention in recent years, the number of people suffering from neoplastic syndrome continues to increase. Despite notable improvements in the field of cancer therapy, tackling cancer has been challenging due to the multiple properties of cancer cells and their ability to evade the immune system. Probiotics alter the immunological and cellular responses by enhancing the epithelial barrier and stimulating the production of anti-inflammatory, antioxidant, and anticarcinogenic compounds, thereby reducing cancer burden and growth. The present review focuses on the various mechanisms underlying the role of probiotics in the prevention and treatment of cancer.

Is Culture Expansion Necessary in Autologous Mesenchymal Stromal Cell Therapy to Obtain Superior Results in the Management of Knee Osteoarthritis?-Meta-Analysis of Randomized Controlled Trials

Study Design: Meta-analysis. Objectives: We aimed to analyze the impact of cultured expansion of autologous mesenchymal stromal cells (MSCs) in the management of osteoarthritis of the knee from randomized controlled trials (RCTs) available in the literature. Materials and Methods: We conducted independent and duplicate electronic database searches including PubMed, Embase, Web of Science, and Cochrane Library until August 2021 for RCTs analyzing the efficacy and safety of culture-expanded compared to non-cultured autologous MSCs in the management of knee osteoarthritis. The Visual Analog Score (VAS) for pain, Western Ontario McMaster University's Osteoarthritis Index (WOMAC), Lysholm score, Knee Osteoarthritis Outcome Score (KOOS), and adverse events were the analyzed outcomes. Analysis was performed in R-platform using OpenMeta [Analyst] software. Results: Overall, 17 studies involving 767 patients were included for analysis. None of the studies made a direct comparison of the culture expanded and non-cultured MSCs, hence we pooled the results of all the included studies of non-cultured and cultured types of MSC sources and made a comparative analysis of the outcomes. At six months, culture expanded MSCs showed significantly better improvement (p < 0.001) in VAS outcome. Uncultured MSCs, on the other hand, demonstrated significant VAS improvement in the long term (12 months) in VAS (p < 0.001), WOMAC (p = 0.025), KOOS score (p = 0.016) where cultured-expanded MSCs failed to demonstrate a significant change. Culturing of MSCs did not significantly increase the complications noted (p = 0.485). On sub-group analysis, adipose-derived uncultured MSCs outperformed culture-expanded MSCs at both short term (six months) and long term (12 months) in functional outcome parameters such as WOMAC (p < 0.001, p = 0.025), Lysholm (p < 0.006), and KOOS (p < 0.003) scores, respectively, compared to their controls. Conclusions: We identified a void in literature evaluating the impact of culture expansion of MSCs for use in knee osteoarthritis. Our indirect analysis of literature showed that culture expansion of autologous MSCs is not a necessary factor to obtain superior results in the management of knee osteoarthritis. Moreover, while using uncultured autologous MSCs, we recommend MSCs of adipose origin to obtain superior functional outcomes. However, we urge future trials of sufficient quality to validate our findings to arrive at a consensus on the need for culture expansion of MSCs for use in cellular therapy of knee osteoarthritis.

Osteogenic and Chondrogenic Potential of Periosteum-Derived Mesenchymal Stromal Cells: Do They Hold the Key to the Future?

The periosteum, with its outer fibrous and inner cambium layer, lies in a dynamic environment with a niche of pluripotent stem cells for their reparative needs. The inner cambium layer is rich in mesenchymal progenitors, osteogenic progenitors, osteoblasts, and fibroblasts in a scant collagen matrix environment. Their role in union and remodeling of fracture is well known. However, the periosteum as a source of mesenchymal stem cells has not been explored in detail. Moreover, with the continuous expansion of techniques, newer insights have been acquired into the roles and regulation of these periosteal cells. From a therapeutic standpoint, the periosteum as a source of tissue engineering has gained much attraction. Apart from its role in bone repair, analysis of the bone-forming potential of periosteum-derived stem cells is lacking. Hence, this article elucidates the role of the periosteum as a potential source of mesenchymal stem cells along with their capacity for osteogenic and chondrogenic differentiation for therapeutic application in the future.

Where Do We Stand in Stem Cell Therapy for the Management of Diabetes Mellitus?-A Scientometric Research Trend Analysis from 1990 to 2020

Stem cell therapy has been considered a promising strategy in the management of both type I and type II diabetes mellitus (DM) because of its immunomodulatory and regenerative capability to restore the beta cell number and function. Various modalities of cellular therapy like transplantation of pancreatic islet cells, transplantation of pancreatic ductal stem cells, and mesenchymal stromal cell transplantation have been tried, and the modality is undergoing rapid advancements that may become the reality in the near future. In the course of its evolution, it is essential to have a comprehensive summary of the progress for a greater capacity to refine our future directives. With technological developments like data mining, graphic drawing, and information analytics combined with computational statistics, visualization of scientific metrology has become a reality. With a newer perspective, we intend to use scientometric tools including text mining, co-word analysis, word frequency analysis, co-citation analysis, cluster network analysis, to perform a systematic and comprehensive analysis of the research trend in stem cell therapy in the management of DM over the past three decades (1990-2020) and to identify the future research hotspots.

Extracellular Vesicles Act as Nano-Transporters of Tyrosine Kinase Inhibitors to Revert Iodine Avidity in Thyroid Cancer

A new approach for using extracellular vesicles (EVs) to deliver tyrosine kinase inhibitors (TKIs) to enhance iodine avidity in radioactive iodine-refractory thyroid cancer is needed. We isolated and characterized primary human adipose-derived stem cells (ADSCs) and isolated their EVs. The EVs were characterized by transmission electron microscopy, nanoparticle tracking analysis, and western blotting. A new TKI was loaded into the EVs by incubation (37 °C; 10 min) or sonication (18 cycles; 4 s per cycle) with 2 s intervals and a 2 min ice bath every six cycles. TKI loading was confirmed and measured by mass spectrometry. EV uptake into radioactive iodine-refractory thyroid cancer cells (SW1736 cells) was confirmed by microscopy. We treated the SW1736 cells with vehicle, TKI, or TKI-loaded EVs (sonication TKI-loaded EVs [EVs^TKI(S)]) and examined the expression of iodide-metabolizing proteins and radioiodine uptake in the SW1736 cells. ADSCs cells showed >99% of typical stem cell markers, such as CD90 and CD105. The EVs displayed a round morphology, had an average size of 211.4 ± 3.83 nm, and were positive for CD81 and Alix and negative for cytochrome c. The mass spectrometry results indicate that the sonication method loaded ~4 times more of the TKI than did the incubation method. The EVs^TKI(S) were used for further experiments. Higher expression levels of iodide-metabolizing mRNA and proteins in the EVs^TKI(S)-treated SW1736 cells than in TKI-treated SW1736 cells were confirmed. EVs^TKI(S) treatment enhanced ¹²⁵I uptake in the recipient SW1736 cells compared with free-TKI treatment. This is the first study that demonstrated successful delivery of a TKI to radioactive iodine-refractory thyroid cancer cells using EVs as the delivery vehicle. This approach can revert radioiodine-resistant thyroid cancer cells back to radioiodine-sensitive thyroid cancer cells.

Noninvasive in vivo cell tracking using molecular imaging: A useful tool for developing mesenchymal stem cell-based cancer treatment

Mounting evidence has emphasized the potential of cell therapies in treating various diseases by restoring damaged tissues or replacing defective cells in the body. Cell therapies have become a strong therapeutic modality by applying noninvasive in vivo molecular imaging for examining complex cellular processes, understanding pathophysiological mechanisms of diseases, and evaluating the kinetics/dynamics of cell therapies. In particular, mesenchymal stem cells (MSCs) have shown promise in recent years as drug carriers for cancer treatment. They can also be labeled with different probes and tracked in vivo to assess the in vivo effect of administered cells, and to optimize therapy. The exact role of MSCs in oncologic diseases is not clear as MSCs have been shown to be involved in tumor progression and inhibition, and the exact interactions between MSCs and specific cancer microenvironments are not clear. In this review, a multitude of labeling approaches, imaging modalities, and the merits/demerits of each strategy are outlined. In addition, specific examples of the use of MSCs and in vivo imaging in cancer therapy are provided. Finally, present limitations and future outlooks in terms of the translation of different imaging approaches in clinics are discussed.

Application of In Vivo Imaging Techniques for Monitoring Natural Killer Cell Migration and Tumor Infiltration

In recent years, the use of natural killer (NK) cell-based immunotherapy has shown promise against various cancer types. To some extent therapeutic potential of NK cell-based immunotherapy depends on migration of NK cells towards tumors in animal models or human subjects and subsequent infiltration. Constant improvement in the pharmacological and therapeutic properties of NK cells is driving the performance and use of NK cell-based immunotherapies. In this review, we summarize the molecular imaging techniques used in monitoring the migration and infiltration of NK cells in vivo at preclinical and clinical levels. A review of pros and cons of each molecular imaging modality is done. Finally, we provide our perception of the usefulness of molecular imaging approaches for in vivo monitoring of NK cells in preclinical and clinical scenarios.

Extracellular Vesicle- and Extracellular Vesicle Mimetics-Based Drug Delivery Systems: New Perspectives, Challenges, and Clinical Developments

Extracellular vesicles (EVs) are small membrane-based nanovesicles naturally released from cells. Extracellular vesicles mimetics (EVMs) are artificial vesicles engineered from cells or in combination with lipid materials, and they mimic certain characteristics of EVs. As such, EVs facilitate intracellular communication by carrying and delivering biological materials, such as proteins, lipids, and nucleic acids, and they have been found to find organ tropism in preclinical studies. Because of their native structure and characteristics, they are considered promising drug carriers for future clinical use. This review outlines the origin and composition of natural EVs and EVM engineering and internalization. It then details different loading approaches, with examples of the drug delivery of therapeutic molecules. In addition, the advantages and disadvantages of loading drugs into EVs or EVMs as a drug delivery system are discussed. Finally, the advantages of EVMs over EVs and the future clinical translation of EVM-based drug delivery platforms are outlined.

Regulated Mesenchymal Stem Cells Mediated Colon Cancer Therapy Assessed by Reporter Gene Based Optical Imaging

Colorectal cancer is the most common cancer in both men and women and the second most common cause of cancer-related deaths. Suicide gene-based therapy with suicide gene-transduced mesenchymal stem cells (MSCs) is a promising therapeutic strategy. A tetracycline-controlled Tet-On inducible system used to regulate gene expression may be a useful tool for gene-based therapies. The aim of this study was to develop therapeutic MSCs with a suicide gene that is induced by an artificial stimulus, to validate therapeutic gene expression, and to monitor the MSC therapy for colon cancer using optical molecular imaging. For our study, we designed the Tet-On system using a retroviral vector and developed a response plasmid RetroX-TRE (tetracycline response element) expressing a mutant form of herpes simplex virus thymidine kinase (HSV1-sr39TK) with dual reporters (eGFP-Fluc2). Bone marrow-derived MSCs were transduced using a RetroX-Tet3G (Clontech, CA, USA) regulatory plasmid and RetroX-TRE-HSV1-sr39TK-eGFP-IRES-Fluc2, for a system with a Tet-On (MSC-Tet-TK/Fluc2 or MSC-Tet-TK) or without a Tet-On (MSC-TK/Fluc2 or MSC-TK) function. Suicide gene engineered MSCs were co-cultured with colon cancer cells (CT26/Rluc) in the presence of the prodrug ganciclovir (GCV) after stimulation with or without doxycycline (DOX). Treatment efficiency was monitored by assessing Rluc (CT26/Rluc) and Fluc (MSC-Tet-TK and MSC-TK) activity using optical imaging. The bystander effect of therapeutic MSCs was confirmed in CT26/Rluc cells after GCV treatment. Rluc activity in CT26/Rluc cells decreased significantly with GCV treatment of DOX(+) cells (p < 0.05 and 0.01) whereas no significant changes were observed in DOX(-) cells. In addition, Fluc activity in also decreased significantly with DOX(+) MSC-Tet-TK cells, but no signal was observed in DOX(-) cells. In addition, an MSC-TK bystander effect was also confirmed. We assessed therapy with this system in a colon cancer xenograft model (CT26/Rluc). We successfully transduced cells and developed a Tet-On system with the suicide gene HSV1-sr39TK. Our results confirmed the therapeutic efficiency of a suicide gene with the Tet-On system for colon cancer. In addition, our results provide an innovative therapeutic approach using the Tet-On system to eradicate tumors by administration of MSC-Tet-TK cells with DOX and GCV.

Extracellular vesicles from mesenchymal stem cells activates VEGF receptors and accelerates recovery of hindlimb ischemia

Extracellular vesicles (EVs) derived from mesenchymal stem cells (MSCs) are potential therapies for various diseases, but their angiogenic mechanisms of therapeutic efficacy remain unclear. Here, we describe how MSC-EVs, activates VEGF receptors and downstream angiogenesis pathways. Mouse MSC-EVs were isolated from cell culture medium and characterized using transmission electron microscopy, nanoparticle analysis, and western blotting. In vitro migration, proliferation, and tube formation assays using endothelial cells were used to assess the angiogenic potential of MSC-EVs, and revealed higher levels of cellular migration, proliferation, and tube formation after treatment. qRT-PCR and western blotting (WB) revealed higher protein and mRNA expression of the angiogenic genes VEGFR1 and VEGFR2 in mouse SVEC-4 endothelial cells after MSC-EVs treatment. Additionally, other vital pro-angiogenic pathways (SRC, AKT, and ERK) were activated by in vitro MSC-EV treatment. WB and qRT-PCR revealed enriched presence of VEGF protein and miR-210-3p in MSC-EV. The hindlimb ischemia mouse model was established and MSC-EVs with or without Matrigel (EV-MSC+Gel) were injected into the ischemic area and blood reperfusion was monitored using molecular imaging techniques. The in vivo administration of MSC-EVs increased both blood reperfusion and the formation of new blood vessels in the ischemic limb, with the addition of matrigel enhancing this effect further by releasing EVs slowly. MSC-EVs enhance angiogenesis in ischemic limbs, most likely via the overexpression of VEGFR1 and VEGFR2 in endothelial cells. These findings reveal a novel mechanism of activating receptors by MSC-EVs influence the angiogenesis.