Tendon Decellularized Matrix Modified Fibrous Scaffolds with Porous and Crimped Microstructure for Tendon Regeneration.

Current engineered synthetic scaffolds fail to functionally repair and regenerate ruptured native tendon tissues, partly because they cannot satisfy both the unique biological and biomechanical properties of these tissues. Ideal scaffolds for tendon repair and regeneration need to provide porous topographic structures and biological cues necessary for the efficient infiltration and tenogenic differentiation of embedded stem cells. To obtain crimped and porous scaffolds, highly aligned poly(l-lactide) fibers were prepared by electrospinning followed by postprocessing. Through a mild and controlled hydrogen gas foaming technique, we successfully transformed the crimped fibrous mats into three-dimensional porous scaffolds without sacrificing the crimped microstructure. Porcine derived decellularized tendon matrix was then grafted onto this porous scaffold through fiber surface modification and carbodiimide chemistry. These biofunctionalized, crimped, and porous scaffolds supported the proliferation, migration, and tenogenic induction of tendon derived stem/progenitor cells, while enabling adhesion to native tendons. Together, our data suggest that these biofunctionalized scaffolds can be exploited as promising engineered scaffolds for the treatment of acute tendon rupture.

Silencing of transient receptor potential canonical channel 4 inhibits endothelial progenitor cell angiogenesis by suppressing VEGF and SDF-1.

OBJECTIVES: Endothelial progenitor cells (EPCs) play a crucial role in acquired angiogenesis and endothelial injury repair. Transient receptor potential canonical channel 4 (TRPC4), a key component of store-operated calcium channels, is essential for EPC function. While the role of TRPCs has been clarified in vascular diseases, the relationship between TRPC4 and EPC function, along with the underlying molecular mechanisms, remains unclear and requires further elucidation. METHODS: EPCs were isolated from canine bone marrow and identified by morphology and flow cytometry. TRPC4 was transfected into EPCs using lentivirus or negative control, and its expression was assessed using real-time polymerase chain reaction (RT-PCR). Proliferation, migration, and tube formation were evaluated using Cell Counting Kit-8 (CCK-8), Transwell, and Matrigel assays, respectively. Levels of vascular endothelial growth factor (VEGF) and stromal cell-derived factor-1 (SDF-1) were measured using enzyme-linked immunosorbent assay (ELISA). RESULTS: TRPC4 mRNA expression was significantly reduced in TRPC4-short hairpin RNA (shRNA) transfected EPCs compared to the normal control (NC)-shRNA groups. Migration and tube formation were significantly decreased after TRPC4 silencing, while proliferation showed no difference. Additionally, levels of SDF-1 and VEGF in EPCs were markedly reduced following TRPC4 silencing. CONCLUSION: TRPC4 plays a crucial role in regulating angiogenesis in EPCs. Silencing of TRPC4 can lead to decreased angiogenesis by inhibiting VEGF and SDF-1 expression, suggesting that TRPC4 knockdown might be a novel therapeutic strategy for vascular diseases.

Upregulation of FABP4 induced inflammation in the pathogenesis of chronic tendinopathy.

Objectives: Excessive inflammation contributes to the pathogenesis of tendinopathy. Fatty acid binding protein 4 (FABP4) is a pro-inflammatory adipokine mediating various metabolic and inflammatory diseases. This study aimed to examine the expression of FABP4 and its association with the expressions of inflammatory cytokines in tendinopathy. The effects of a single injection of FABP4 on tendon pathology and inflammation were examined. The effect of FABP4 on the expressions of inflammatory cytokines and the effect of IL-1ß on the expression of FABP4 in tendon-derived stem/progenitor cells (TDSCs) were also investigated. Methods: 1) Clinical patellar tendinopathy samples, healthy hamstring tendon samples, and healthy patellar tendon samples, 2) rotator cuff tendinopathy samples and healthy hamstring tendon samples; and 3) Achilles tendons of mice after saline or collagenase injection (CI) were stained for FABP4, IL-1ß, IL-6, TNF-α and IL-10 by immunohistochemistry (IHC). For the rotator cuff tendinopathy samples, co-localization of FABP4 with IL-1ß and TNF-α was done by immunofluorescent staining (IF). Mouse Achilles tendons injected with FABP4 or saline were collected for histology and IHC as well as microCT imaging post-injection. TDSCs were isolated from human and mouse tendons. The mRNA expressions of inflammatory cytokines in human and mouse TDSCs after the addition of FABP4 was quantified by qRT-PCR. The expression of FABP4 in TDSCs isolated from rotator cuff tendinopathy samples and healthy hamstring tendon samples was examined by IF. Mouse Achilles TDSCs were treated with IL-1ß. The mRNA and protein expressions of FABP4 were examined by qRT-PCR and IF, respectively. Results: There was significant upregulation of FABP4 in the patellar tendinopathy samples and rotator cuff tendinopathy samples compared to their corresponding controls. FABP4 was mainly expressed in the pathological areas including blood vessels, hypercellular and calcified regions. The expressions of IL-1ß and TNF-α increased in human rotator cuff tendinopathy samples and co-localized with the expression of FABP4. Collagenase induced tendinopathic-like histopathological changes and ectopic calcification in the mouse Achilles tendinopathy model. The expressions of inflammatory cytokines (IL-1ß, IL-6, TNF-α, IL-10) and FABP4 increased in hypercellular region, round cells chondrocyte-like cells and calcified regions in the mouse Achilles tendons post-collagenase injection. A single injection of FABP4 in mouse Achilles tendons induced histopathological changes resembling tendinopathy, with increased cell rounding, loss of collagen fiber alignment, and additionally presence of chondrocyte-like cells and calcification post-injection. The expressions of IL1-ß, IL-6, TNF-α and IL-10 increased in mouse Achilles tendons post-FABP4 injection. FABP4 increased the expressions of IL10, IL6, and TNFa in human TDSCs as well as the expressions of Il1b, Il6, and Il10 in mouse TDSCs. Human tendinopathy TDSCs expressed higher level of FABP4 compared to healthy hamstring TDSCs. Besides, IL-1ß increased the expression of FABP4 in mouse TDSCs. Conclusion: In conclusion, an upregulation of FABP4 is involved in excessive inflammation and pathogenesis of tendinopathy. TDSCs is a potential source of FABP4 during tendon inflammation. Translation potential of this article: FABP4 can be a potential treatment target of tendinopathy.

Transcriptional Control: A Directional Sign at the Crossroads of Adult Hepatic Progenitor Cells' Fates.

Hepatic progenitor cells (HPCs) have a bidirectional potential to differentiate into hepatocytes and bile duct epithelial cells and constitute a second barrier to liver regeneration in the adult liver. They are usually located in the Hering duct in the portal vein region where various cells, extracellular matrix, cytokines, and communication signals together constitute the niche of HPCs in homeostasis to maintain cellular plasticity. In various types of liver injury, different cellular signaling streams crosstalk with each other and point to the inducible transcription factor set, including FoxA1/2/3, YB-1, Foxl1, Sox9, HNF4α, HNF1α, and HNF1ß. These transcription factors exert different functions by binding to specific target genes, and their products often interact with each other, with diverse cascades of regulation in different molecular events that are essential for homeostatic regulation, self-renewal, proliferation, and selective differentiation of HPCs. Furthermore, the tumor predisposition of adult HPCs is found to be significantly increased under transcriptional factor dysregulation in transcriptional analysis, and the altered initial commitment of the differentiation pathway of HPCs may be one of the sources of intrahepatic tumors. Related transcription factors such as HNF4α and HNF1 are expected to be future targets for tumor treatment.

Modern advances in spinal cord regeneration: hydrogel combined with neural stem cells.

Severe spinal cord injuries (SCI) lead to loss of functional activity of the body below the injury site, affect a person's ability to self-care and have a direct impact on performance. Due to the structural features and functional role of the spinal cord in the body, the consequences of SCI cannot be completely overcome at the expense of endogenous regenerative potential and, developing over time, lead to severe complications years after injury. Thus, the primary task of this type of injury treatment is to create artificial conditions for the regenerative growth of damaged nerve fibers through the area of the SCI. Solving this problem is possible using tissue neuroengineering involving the technology of replacing the natural tissue environment with synthetic matrices (for example, hydrogels) in combination with stem cells, in particular, neural/progenitor stem cells (NSPCs). This approach can provide maximum stimulation and support for the regenerative growth of axons of damaged neurons and their myelination. In this review, we consider the currently available options for improving the condition after SCI (use of NSC transplantation or/and replacement of the damaged area of the SCI with a matrix, specifically a hydrogel). We emphasise the expediency and effectiveness of the hydrogel matrix + NSCs complex system used for the reconstruction of spinal cord tissue after injury. Since such a complex approach (a combination of tissue engineering and cell therapy), in our opinion, allows not only to creation of conditions for supporting endogenous regeneration or mechanical reconstruction of the spinal cord, but also to strengthen endogenous regeneration, prevent the spread of the inflammatory process, and promote the restoration of lost reflex, motor and sensory functions of the injured area of spinal cord.

Establishment of a humanized mouse model using steady-state peripheral blood-derived hematopoietic stem and progenitor cells facilitates screening of cancer-targeted T-cell repertoires.

Background: Cancer-targeted T-cell receptor T (TCR-T) cells hold promise in treating cancers such as hematological malignancies and breast cancers. However, approaches to obtain cancer-reactive TCR-T cells have been unsuccessful. Methods: Here, we developed a novel strategy to screen for cancer-targeted TCR-T cells using a special humanized mouse model with person-specific immune fingerprints. Rare steady-state circulating hematopoietic stem and progenitor cells were expanded via three-dimensional culture of steady-state peripheral blood mononuclear cells, and then the expanded cells were applied to establish humanized mice. The human immune system was evaluated according to the kinetics of dendritic cells, monocytes, T-cell subsets, and cytokines. To fully stimulate the immune response and to obtain B-cell precursor NAML-6- and triple-negative breast cancer MDA-MB-231-targeted TCR-T cells, we used the inactivated cells above to treat humanized mice twice a day every 7 days. Then, human T cells were processed for TCR ß-chain (TRB) sequencing analysis. After the repertoires had been constructed, features such as the fraction, diversity, and immune signature were investigated. Results: The results demonstrated an increase in diversity and clonality of T cells after treatment. The preferential usage and features of TRBV, TRBJ, and the V-J combination were also changed. The stress also induced highly clonal expansion. Tumor burden and survival analysis demonstrated that stress induction could significantly inhibit the growth of subsequently transfused live tumor cells and prolong the survival of the humanized mice. Conclusions: We constructed a personalized humanized mouse model to screen cancer-targeted TCR-T pools. Our platform provides an effective source of cancer-targeted TCR-T cells and allows for the design of patient-specific engineered T cells. It therefore has the potential to greatly benefit cancer treatment.

Single-cell sequencing unveils the impact of aging on the progenitor cell diversity in the telencephalon of the female killifish N. furzeri.

The African turquoise killifish (Nothobranchius furzeri) combines a short lifespan with spontaneous age-associated loss of neuro-regenerative capacity, an intriguing trait atypical for a teleost. The impact of aging on the cellular composition of the adult stem cell niches, leading to this dramatic decline in the postnatal neuro- and gliogenesis, remains elusive. Single-cell RNA sequencing of the telencephalon of young adult female killifish of the short-lived GRZ-AD strain unveiled progenitors of glial and non-glial nature, different excitatory and inhibitory neuron subtypes, as well as non-neural cell types. Sub-clustering of the progenitors identified four radial glia (RG) cell types, two non-glial progenitor (NGP) and four intermediate (intercell) cell states. Two astroglia-like, one ependymal, and one neuroepithelial-like (NE) RG subtype were found at different locations in the forebrain in line with their role, while proliferative, active NGPs were spread throughout. Lineage inference pointed to NE-RG and NGPs as start and intercessor populations for glio- and neurogenesis. Upon aging, single-cell RNA sequencing revealed major perturbations in the proportions of the astroglia and intercell states, and in the molecular signatures of specific subtypes, including altered MAPK, mTOR, Notch, and Wnt pathways. This cell catalog of the young regeneration-competent killifish telencephalon, combined with the evidence for aging-related transcriptomic changes, presents a useful resource to understand the molecular basis of age-dependent neuroplasticity. This data is also available through an online database (killifishbrain_scseq).

Hsa-miR-134-5p predicts cardiovascular risk in circulating mononuclear cells and improves angiogenic action of senescent endothelial progenitor cells.

This research explores the role of microRNA in senescence of human endothelial progenitor cells (EPCs) induced by replication. Hsa-miR-134-5p was found up-regulated in senescent EPCs where overexpression improved angiogenic activity. Hsa-miR-134-5p, which targeted transforming growth factor ß-activated kinase 1-binding protein 1 (TAB1) gene, down-regulated TAB1 protein, and inhibited phosphorylation of p38 mitogen-activated protein kinase (p38) in hsa-miR-134-5p-overexpressed senescent EPCs. Treatment with siRNA specific to TAB1 (TAB1si) down-regulated TAB1 protein and subsequently inhibited p38 activation in senescent EPCs. Treatment with TAB1si and p38 inhibitor, respectively, showed angiogenic improvement. In parallel, transforming growth factor Beta 1 (TGF-ß1) was down-regulated in hsa-miR-134-5p-overexpressed senescent EPCs and addition of TGF-ß1 suppressed the angiogenic improvement. Analysis of peripheral blood mononuclear cells (PBMCs) disclosed expression levels of hsa-miR-134-5p altered in adult life, reaching a peak before 65 years, and then falling in advanced age. Calculation of the Framingham risk score showed the score inversely correlates with the hsa-miR-134-5p expression level. In summary, hsa-miR-134-5p is involved in the regulation of senescence-related change of angiogenic activity via TAB1-p38 signalling and via TGF-ß1 reduction. Hsa-miR-134-5p has a potential cellular rejuvenation effect in human senescent EPCs. Detection of human PBMC-derived hsa-miR-134-5p predicts cardiovascular risk.

Purinosomes and Purine Metabolism in Mammalian Neural Development: A Review.

Neural stem/progenitor cells (NSPCs) in specific brain regions require precisely regulated metabolite production during critical development periods. Purines-vital components of DNA, RNA, and energy carriers like ATP and GTP-are crucial metabolites in brain development. Purine levels are tightly controlled through two pathways: de novo synthesis and salvage synthesis. Enzymes driving de novo pathway are assembled into a large multienzyme complex termed the "purinosome." Here, we review purine metabolism and purinosomes as spatiotemporal regulators of neural development. Notably, around postnatal day 0 (P0) during mouse cortical development, purine synthesis transitions from the de novo pathway to the salvage pathway. Inhibiting the de novo pathway affects mTORC1 pathway and leads to specific forebrain malformations. In this review, we also explore the importance of protein-protein interactions of a newly identified NSPC protein-NACHT and WD repeat domain-containing 1 (Nwd1)-in purinosome formation. Reduced Nwd1 expression disrupts purinosome formation, impacting NSPC proliferation and neuronal migration, resulting in periventricular heterotopia. Nwd1 interacts directly with phosphoribosylaminoimidazole-succinocarboxamide synthetase (PAICS), an enzyme involved in de novo purine synthesis. We anticipate this review will be valuable for researchers investigating neural development, purine metabolism, and protein-protein interactions.

Hematopoietic Stem Cells and Their Niche in Bone Marrow.

Extensive research has explored the functional correlation between stem cells and progenitor cells, particularly in blood. Hematopoietic stem cells (HSCs) can self-renew and regenerate tissues within the bone marrow, while stromal cells regulate tissue function. Recent studies have validated the role of mammalian stem cells within specific environments, providing initial empirical proof of this functional phenomenon. The interaction between bone and blood has always been vital to the function of the human body. It was initially proposed that during evolution, mammalian stem cells formed a complex relationship with the surrounding microenvironment, known as the niche. Researchers are currently debating the significance of molecular-level data to identify individual stromal cell types due to incomplete stromal cell mapping. Obtaining these data can help determine the specific activities of HSCs in bone marrow. This review summarizes key topics from previous studies on HSCs and their environment, discussing current and developing concepts related to HSCs and their niche in the bone marrow.

Umbilical Cord Blood Hematopoietic Cells: From Biology to Hematopoietic Transplants and Cellular Therapies.

Umbilical cord blood (UCB) is a rich source of hematopoietic stem and progenitor cells that are biologically superior to their adult counterparts. UCB cells can be stored for several years without compromising their numbers or function. Today, public and private UCB banks have been established in several countries around the world. After 35 years since the first UCB transplant (UCBT), more than 50,000 UCBTs have been performed worldwide. In pediatric patients, UCBT is comparable to or superior to bone marrow transplantation. In adult patients, UCB can be an alternative source of hematopoietic cells when an HLA-matched unrelated adult donor is not available and when a transplant is urgently needed. Delayed engraftment (due to reduced absolute numbers of hematopoietic cells) and higher costs have led many medical institutions not to consider UCB as a first-line cell source for hematopoietic transplants. As a result, the use of UCB as a source of hematopoietic stem and progenitor cells for transplantation has declined over the past decade. Several approaches are being investigated to make UCBTs more efficient, including improving the homing capabilities of primitive UCB cells and increasing the number of hematopoietic cells to be infused. Several of these approaches have already been applied in the clinic with promising results. UCB also contains immune effector cells, including monocytes and various lymphocyte subsets, which, together with stem and progenitor cells, are excellent candidates for the development of cellular therapies for hematological and non-hematological diseases.

Identification and Characterization of ATOH7-Regulated Target Genes and Pathways in Human Neuroretinal Development.

The proneural transcription factor atonal basic helix-loop-helix transcription factor 7 (ATOH7) is expressed in early progenitors in the developing neuroretina. In vertebrates, this is crucial for the development of retinal ganglion cells (RGCs), as mutant animals show an almost complete absence of RGCs, underdeveloped optic nerves, and aberrations in retinal vessel development. Human mutations are rare and result in autosomal recessive optic nerve hypoplasia (ONH) or severe vascular changes, diagnosed as autosomal recessive persistent hyperplasia of the primary vitreous (PHPVAR). To better understand the role of ATOH7 in neuroretinal development, we created ATOH7 knockout and eGFP-expressing ATOH7 reporter human induced pluripotent stem cells (hiPSCs), which were differentiated into early-stage retinal organoids. Target loci regulated by ATOH7 were identified by Cleavage Under Targets and Release Using Nuclease with sequencing (CUT&RUN-seq) and differential expression by RNA sequencing (RNA-seq) of wildtype and mutant organoid-derived reporter cells. Additionally, single-cell RNA sequencing (scRNA-seq) was performed on whole organoids to identify cell type-specific genes. Mutant organoids displayed substantial deficiency in axon sprouting, reduction in RGCs, and an increase in other cell types. We identified 469 differentially expressed target genes, with an overrepresentation of genes belonging to axon development/guidance and Notch signaling. Taken together, we consolidate the function of human ATOH7 in guiding progenitor competence by inducing RGC-specific genes while inhibiting other cell fates. Furthermore, we highlight candidate genes responsible for ATOH7-associated optic nerve and retinovascular anomalies, which sheds light to potential future therapy targets for related disorders.

SRSF10 regulates migration of neural progenitor cells and granule cells and affects the formation of dentate gyrus during the development of mouse hippocampus.

Hippocampus is a critical component of the central nervous system. SRSF10 is expressed in central nervous system and plays important roles in maintaining normal brain functions. However, its role in hippocampus development is unknown. In this study, using SRSF10 conditional knock-out mice in neural progenitor cells (NPCs), we found that dysfunction of SRSF10 leads to developmental defects in the dentate gyrus of hippocampus, which manifests as the reduced length and wider suprapyramidal blade and infrapyramidal blade.Furthermore, we proved that loss of SRSF10 in NPCs caused inhibition of the differentiation activity and the abnormal migration of NPCs and granule cells, resulting in reduced granule cells and more ectopic granule cells dispersed in the molecular layer and hilus. Finally, we found that the abnormal migration may be caused by the radial glia scaffold and the reduced DISC1 expression in NPCs. Together, our results indicate that SRSF10 is required for the cell migration and formation of dentate gyrus during the development of hippocampus.

Early heart development: examining the dynamics of function-form emergence.

During early embryonic development, the heart undergoes a remarkable and complex transformation, acquiring its iconic four-chamber structure whilst concomitantly contracting to maintain its essential function. The emergence of cardiac form and function involves intricate interplays between molecular, cellular, and biomechanical events, unfolding with precision in both space and time. The dynamic morphological remodelling of the developing heart renders it particularly vulnerable to congenital defects, with heart malformations being the most common type of congenital birth defect (∼35% of all congenital birth defects). This mini-review aims to give an overview of the morphogenetic processes which govern early heart formation as well as the dynamics and mechanisms of early cardiac function. Moreover, we aim to highlight some of the interplay between these two processes and discuss how recent findings and emerging techniques/models offer promising avenues for future exploration. In summary, the developing heart is an exciting model to gain fundamental insight into the dynamic relationship between form and function, which will augment our understanding of cardiac congenital defects and provide a blueprint for potential therapeutic strategies to treat disease.

Proteomic profiling of regenerated urinary bladder tissue in a non-human primate augmentation model.

Urinary bladder dysfunction can be caused by environmental, genetic, and developmental insults. Depending upon insult severity, the bladder may lose its ability to maintain volumetric capacity and intravesical pressure resulting in renal deterioration. Bladder augmentation enterocystoplasty (BAE) is utilized to increase bladder capacity to preserve renal function using autologous bowel tissue as a "patch." To avoid the clinical complications associated with this procedure, we have engineered composite grafts comprised of autologous bone marrow mesenchymal stem cells (MSCs) co-seeded with CD34+ hematopoietic stem/progenitor cells (HSPCs) onto a pliable synthetic scaffold [poly(1,8-octamethylene-citrate-co-octanol)(POCO)] or a biological scaffold (SIS; small intestinal submucosa) to regenerate bladder tissue in our baboon bladder augmentation model. We set out to determine the global protein expression profile of bladder tissue that has undergone regeneration with the aforementioned stem cell seeded scaffolds along with baboons that underwent BAE. Data demonstrate that POCO and SIS grafted animals share high protein homogeneity between native and regenerated tissues while BAE animals displayed heterogeneous protein expression between the tissues following long-term engraftment. We posit that stem cell-seeded scaffolds can recapitulate tissue that is nearly indistinguishable from native tissue at the protein level and may be used in lieu of procedures such as BAE.

Integrative Analysis of Long Isoform Sequencing and Functional Data Identifies Distinct Cortical Layer Neuronal Subtypes Derived from Human iPSCs.

Generation of human induced pluripotent stem cells (iPSCs) through reprogramming was a transformational change in the field of regenerative medicine that led to new possibilities for drug discovery and cell replacement therapy. Several protocols have been established to differentiate hiPSCs into neuronal lineages. However, low differentiation efficiency is one of the major drawbacks of these approaches. Here, we compared the efficiency of two methods of neuronal differentiation from iPSCs cultured in two different culture media, StemFlex Medium (SFM) and Essential 8 Medium (E8M). The results indicated that iPSCs cultured in E8M efficiently generated different types of neurons in a shorter time and without the growth of undifferentiated non-neuronal cells in the culture as compared to those generated from iPSCs in SFM. Furthermore, these neurons were validated as functional units immunocytochemically by confirming the expression of mature neuronal markers (i.e., NeuN, Beta tubulin, and Synapsin I), and whole-cell patch-clamp recordings. Long-read single-cell RNA sequencing confirms the presence of upper and deep layer cortical layer excitatory and inhibitory neuronal subtypes in addition to small populations of GABAergic neurons in day 30 neuronal cultures. Pathway analysis indicated that our protocol triggers the signaling transcriptional networks important for the process of neuronal differentiation in vivo.

Tissue-Engineered Implant for Hemilaryngectomy Reconstruction with Recurrent Laryngeal Nerve Injury.

OBJECTIVE: Laryngeal cancer resections often require excision of portions of the larynx along with sacrifice of the ipsilateral recurrent laryngeal nerve (RLN). In such cases, there are no reconstructive options that reliably restore laryngeal function, rendering patients with severe functional impairment. To address this unmet clinical need, we extend our evaluation of a 3-implant mucosal, muscle, cartilage reconstruction approach aimed at promoting functional laryngeal restoration in a porcine hemilaryngectomy model with ipsilateral RLN transection. METHODS: Six Yucatan mini-pigs underwent full-thickness hemilaryngectomies with RLN transection followed by transmural reconstruction using fabricated collagen polymeric mucosal, muscle, and cartilage replacements. To determine the effect of adding therapeutic cell populations, subsets of animals received collagen muscle implants containing motor-endplate-expressing muscle progenitor cells (MEEs) and/or collagen cartilage implants containing adipose stem cell (ASC)-derived chondrocyte-like cells. Acoustic vocalization and laryngeal electromyography (L-EMG) provided functional assessments and histopathological analysis with immunostaining was used to characterize the tissue response. RESULTS: Five of six animals survived the 4-week postoperative period with weight gain, airway maintenance, and audible phonation. No tracheostomy or feeding tube was required. Gross and histological assessments of all animals revealed implant integration and regenerative remodeling of airway mucosa epithelium, muscle, and cartilage in the absence of a material-mediated foreign body reaction or biodegradation. Early voice and L-EMG data were suggestive of positive functional outcomes. CONCLUSION: Laryngeal reconstruction with collagen polymeric mucosa, muscle, and cartilage replacements may provide effective restoration of function after hemilaryngectomy with RLN transection. Future preclinical studies should focus on long-term functional outcomes. LEVEL OF EVIDENCE: NA Laryngoscope, 2024.

Bone marrow-fibroblast progenitor cell-derived small extracellular vesicles promote cardiac fibrosis via miR-21-5p and integrin subunit αV signalling.

Cardiac fibrosis is the hallmark of cardiovascular disease (CVD), which is leading cause of death worldwide. Previously, we have shown that interleukin-10 (IL10) reduces pressure overload (PO)-induced cardiac fibrosis by inhibiting the recruitment of bone marrow fibroblast progenitor cells (FPCs) to the heart. However, the precise mechanism of FPC involvement in cardiac fibrosis remains unclear. Recently, exosomes and small extracellular vesicles (sEVs) have been linked to CVD progression. Thus, we hypothesized that pro-fibrotic miRNAs enriched in sEV-derived from IL10 KO FPCs promote cardiac fibrosis in pressure-overloaded myocardium. Small EVs were isolated from FPCs cultured media and characterized as per MISEV-2018 guidelines. Small EV's miRNA profiling was performed using Qiagen fibrosis-associated miRNA profiler kit. For functional analysis, sEVs were injected in the heart following TAC surgery. Interestingly, TGFß-treated IL10-KO-FPCs sEV increased profibrotic genes expression in cardiac fibroblasts. The exosomal miRNA profiling identified miR-21a-5p as the key player, and its inhibition with antagomir prevented profibrotic signalling and fibrosis. At mechanistic level, miR-21a-5p binds and stabilizes ITGAV (integrin av) mRNA. Finally, miR-21a-5p-silenced in sEV reduced PO-induced cardiac fibrosis and improved cardiac function. Our study elucidates the mechanism by which inflammatory FPC-derived sEV exacerbate cardiac fibrosis through the miR-21a-5p/ITGAV/Col1α signalling pathway, suggesting miR-21a-5p as a potential therapeutic target for treating hypertrophic cardiac remodelling and heart failure.

Endothelial Progenitor Cells: A Review of Molecular Mechanisms in the Pathogenesis and Endovascular Treatment of Intracranial Aneurysms.

This comprehensive review explores the multifaceted role of endothelial progenitor cells (EPCs) in vascular diseases, focusing on their involvement in the pathogenesis and their contributions to enhancing the efficacy of endovascular treatments for intracranial aneurysms (IAs). Initially discovered as CD34+ bone marrow-derived cells implicated in angiogenesis, EPCs have been linked to vascular repair, vasculogenesis, and angiogenic microenvironments. The origin and differentiation of EPCs have been subject to debate, challenging the conventional notion of bone marrow origin. Quantification methods, including CD34+ , CD133+ , and various assays, reveal the influence of factors, like age, gender, and comorbidities on EPC levels. Cellular mechanisms highlight the interplay between bone marrow and angiogenic microenvironments, involving growth factors, matrix metalloproteinases, and signaling pathways, such as phosphatidylinositol-3-kinase (PI3K) and mitogen-activated protein kinase (MAPK). In the context of the pathogenesis of IAs, EPCs play a role in maintaining vascular integrity by replacing injured and dysfunctional endothelial cells. Recent research has also suggested the therapeutic potential of EPCs after coil embolization and flow diversion, and this has led the development of device surface modifications aimed to enhance endothelialization. The comprehensive insights underscore the importance of further research on EPCs as both therapeutic targets and biomarkers in IAs.