Regenerative Medicine Strategies Research Articles

Research Progress in Hydrogels for Cartilage Organoids.

The repair and regeneration of cartilage has always been a hot topic in medical research. Cartilage organoids (CORGs) are special cartilage tissue created using tissue engineering techniques outside the body. These engineered organoids tissues provide models that simulate the complex biological functions of cartilage, opening new possibilities for cartilage regenerative medicine and treatment strategies. However, it is crucial to establish suitable matrix scaffolds for the cultivation of CORGs. In recent years, utilizing hydrogel to culture stem cells and induce their differentiation into chondrocytes has emerged as a promising method for the in vitro construction of CORGs. In this review, the methods for establishing CORGs are summarized and an overview of the advantages and limitations of using matrigel in the cultivation of such organoids is provided. Furthermore, the importance of cartilage tissue ECM and alternative hydrogel substitutes for Matrigel, such as alginate, peptides, silk fibroin, and DNA derivatives is discussed, and the pros and cons of using these hydrogels for the cultivation of CORGs are outlined. Finally, the challenges and future directions in hydrogel research for CORGs are discussed. It is hoped that this article provides valuable references for the design and development of hydrogels for CORGs.

Insight into the Functional Dynamics and Challenges of Exosomes in Pharmaceutical Innovation and Precision Medicine.

Of all the numerous nanosized extracellular vesicles released by a cell, the endosomal-originated exosomes are increasingly recognized as potential therapeutics, owing to their inherent stability, low immunogenicity, and targeted delivery capabilities. This review critically evaluates the transformative potential of exosome-based modalities across pharmaceutical and precision medicine landscapes. Because of their precise targeted biomolecular cargo delivery, exosomes are posited as ideal candidates in drug delivery, enhancing regenerative medicine strategies, and advancing diagnostic technologies. Despite the significant market growth projections of exosome therapy, its utilization is encumbered by substantial scientific and regulatory challenges. These include the lack of universally accepted protocols for exosome isolation and the complexities associated with navigating the regulatory environment, particularly the guidelines set forth by the U.S. Food and Drug Administration (FDA). This review presents a comprehensive overview of current research trajectories aimed at addressing these impediments and discusses prospective advancements that could substantiate the clinical translation of exosomal therapies. By providing a comprehensive analysis of both the capabilities and hurdles inherent to exosome therapeutic applications, this article aims to inform and direct future research paradigms, thereby fostering the integration of exosomal systems into mainstream clinical practice.

Efficacy of Engraftment and Safety of Human Umbilical Di-Chimeric Cell (HUDC) Therapy after Systemic Intraosseous Administration in an Experimental Model.

Cell-based therapies hold promise for novel therapeutic strategies in regenerative medicine. We previously characterized in vitro human umbilical di-chimeric cells (HUDCs) created via the ex vivo fusion of human umbilical cord blood (UCB) cells derived from two unrelated donors. In this in vivo study, we assessed HUDC safety and biodistribution in the NOD SCID mouse model at 90 days following the systemic intraosseous administration of HUDCs. Twelve NOD SCID mice (n = 6/group) received intraosseous injection of donor UCB cells (3.0 × 106) in Group 1, or HUDCs (3.0 × 106) in Group 2, without immunosuppression. Flow cytometry assessed hematopoietic cell surface markers in peripheral blood and the presence of HLA-ABC class I antigens in lymphoid and non-lymphoid organs. HUDC safety was assessed by weekly evaluations, magnetic resonance imaging (MRI), and at autopsy for tumorigenicity. At 90 days after intraosseous cell administration, the comparable expression of HLA-ABC class I antigens in selected organs was found in UCB control and HUDC therapy groups. MRI and autopsy confirmed safety by no signs of tumor growth. This study confirmed HUDC biodistribution to selected lymphoid organs following intraosseous administration, without immunosuppression. These data introduce HUDCs as a novel promising approach for immunomodulation in transplantation.

First person – Femke (Fen) van Rhijn-Brouwer

ABSTRACT First Person is a series of interviews with the first authors of a selection of papers published in Disease Models & Mechanisms, helping researchers promote themselves alongside their papers. Fen van Rhijn-Brouwer is first author on ‘ Systematic review and meta-analysis of the effect of bone marrow-derived cell therapies on hind limb perfusion’, published in DMM. Fen is a PhD candidate in the lab of Marianne Verhaar at the University Medical Center Utrecht, The Netherlands, investigating how to use cell-based regenerative medicine strategies to treat vascular inflammation.

Understanding the multi-functionality and tissue-specificity of decellularized dental pulp matrix hydrogels for endodontic regeneration

Dental pulp is the only soft tissue in the tooth which plays a crucial role in maintaining intrinsic multi-functional behaviors of the dentin-pulp complex. Nevertheless, the restoration of fully functional pulps after pulpitis or pulp necrosis, termed endodontic regeneration, remained a major challenge for decades. Therefore, a bioactive and in-situ injectable biomaterial is highly desired for tissue-engineered pulp regeneration. Herein, a decellularized matrix hydrogel derived from porcine dental pulps (pDDPM-G) was prepared and characterized through systematic comparison against the porcine decellularized nerve matrix hydrogel (pDNM-G). The pDDPM-G not only exhibited superior capabilities in facilitating multi-directional differentiation of dental pulp stem cells (DPSCs) during 3D culture, but also promoted regeneration of pulp-like tissues after DPSCs encapsulation and transplantation. Further comparative proteomic and transcriptome analyses revealed the differential compositions and potential mechanisms that endow the pDDPM-G with highly tissue-specific properties. Finally, it was realized that the abundant tenascin C (TNC) in pDDPM served as key factor responsible for the activation of Notch signaling cascades and promoted DPSCs odontoblastic differentiation. Overall, it is believed that pDDPM-G is a sort of multi-functional and tissue-specific hydrogel-based material that holds great promise in endodontic regeneration and clinical translation. Statement of significanceFunctional hydrogel-based biomaterials are highly desirable for endodontic regeneration treatments. Decellularized extracellular matrix (dECM) preserves most extracellular matrix components of its native tissue, exhibiting unique advantages in promoting tissue regeneration and functional restoration. In this study, we prepared a porcine dental pulp-derived dECM hydrogel (pDDPM-G), which exhibited superior performance in promoting odontogenesis, angiogenesis, and neurogenesis of the regenerating pulp-like tissue, further showed its tissue-specificity compared to the peripheral nerve-derived dECM hydrogel. In-depth proteomic and transcriptomic analyses revealed that the activation of tenascin C-Notch axis played an important role in facilitating odontogenic regeneration. This biomaterial-based study validated the great potential of the dental pulp-specific pDDPM-G for clinical applications, and provides a springboard for research strategies in ECM-related regenerative medicine.

SDIMMMER: A propaedeutic approach in regenerative medicine

SDIMMMER is a proposed acronym for use in medical interviews. It serves as a mnemonic for key areas to focus on during patient assessments. SDIMMMER stands for Sleep, Diet, Microbiome, Metabolism, Medications, Examination, and Rehabilitation. This approach is designed to assist physicians in efficiently evaluating a patient's metabolic profile as a priority and only then implementing suitable interventional regenerative medicine strategies, ensuring precise clinical diagnosis and increased treatment success rates. This acronym represents a pioneering propaedeutic technique in regenerative medicine. The primary goal of SDIMMMER is to monitor the patient's metabolic status and reduce low-grade chronic systemic inflammation, a prominent feature of metabolic syndrome (MS). This inflammatory state is marked by elevated levels of circulating inflammatory cytokines and increased macrophage infiltration in peripheral tissues. The objective of this propaedeutic proposal is to address and treat the patient holistically, enhancing metabolic function and consequently promoting better health of tissues and organ systems. Ultimately, SDIMMMER aims to increase the efficacy of orthobiological treatments by boosting the levels of growth factors, thereby achieving improved outcomes with patients. Beyond specific treatments, the focus is on guiding patients towards positive lifestyle changes, ultimately enhancing overall quality of life and fostering a healthier metabolism.

Stimuli-Mediated Macrophage Switching, Unraveling the Dynamics at the Nanoplatforms-Macrophage Interface.

Macrophages play an essential role in immunotherapy and tissue regeneration owing to their remarkable plasticity and diverse functions. Recent bioengineering developments have focused on using external physical stimuli such as electric and magnetic fields, temperature, and compressive stress, among others, on micro/nanostructures to induce macrophage polarization, thereby increasing their therapeutic potential. However, it is difficult to find a concise review of the interaction between physical stimuli, advanced micro/nanostructures, and macrophage polarization. This review examines the present research on physical stimuli-induced macrophage polarization on micro/nanoplatforms, emphasizing the synergistic role of fabricated structure and stimulation for advanced immunotherapy and tissue regeneration. We provide a concise overview of the research advancements investigating the impact of physical stimuli-including electric fields, magnetic fields, compressive forces, fluid shear stress, photothermal stimuli, and multiple stimulations on the polarization of macrophages within complex engineered structures. The prospective implications of these strategies in regenerative medicine and immunotherapeutic approaches have been highlighted. This review will aid in creating stimuli-responsive platforms for immunomodulation and tissue regeneration. This article is protected by copyright. All rights reserved.

CpG methylation changes in human mesenchymal and neural stem cells in response to in vitro niche modifications

Stem cell therapies hold promise in addressing the burden of neurodegenerative diseases with human embryonic neural stem cells (hNSC-H9s) and bone marrow-derived human mesenchymal stem cells (hMSCs) as viable candidates. The induction of hMSC neurospheres (hMSC-IN) generate a more lineage-restricted common neural progenitor-like cell population, potentially tunable by heparan sulfate proteoglycans (HSPGs). We examined CpG (5mC) site methylation patterns using Illumina Infinium 850K EPIC arrays in hNSC-H9, hMSCs and hMSC-IN cultures with HSPG agonist heparin at early and late phases of growth. We identified key regulatory CpG sites in syndecans (SDC2; SDC4) that potentially regulate gene expression in monolayers. Unique hMSC-IN hypomethylation in glypicans (GPC3; GPC4) underscore their significance in neural lineages with Sulfatase 1 and 2 (SULF1 &2) CpG methylation changes potentially driving the neurogenic shift. hMSC-INs methylation levels at SULF1 CpG sites and SULF2:cg25401628 were more closely aligned with hNSC-H9 cells than with hMSCs. We further suggest SOX2 regulation governed by lcSOX2-Overall Transcript (lncSOX2-OT) methylation changes with preferential activation of ENO2 over other neuronal markers within hMSC-INs. Our findings illuminate epigenetic dynamics governing neural lineage commitment of hMSC-INs offering insights for targeted mechanisms for regenerative medicine and therapeutic strategies.

Biomaterial-mediated intracellular control of macrophages for cell therapy in pro-inflammatory and pro-fibrotic conditions

Macrophages are key modulators of all inflammatory diseases and essential for their resolution, making macrophage cell therapy a promising strategy for regenerative medicine. However, since macrophages change rapidly in response to microenvironmental cues, their phenotype must be controlled post-administration. We present a tunable biomaterial-based strategy to control macrophages intracellularly via small molecule-releasing microparticles. Poly(lactic-co-glycolic acid) microparticles encapsulating the anti-inflammatory and anti-fibrotic drug dexamethasone were administered to macrophages in vitro, with uptake rates controlled by different loading regimes. Microparticle dose and dexamethasone content directly affected macrophage phenotype and phagocytic capacity, independent of particle content per cell, leading to an overall pro-reparative, anti-inflammatory, anti-fibrotic phenotype with increased phagocytic and ECM degrading functionality. Intracellularly controlled macrophages partially maintained this phenotype in vivo in a murine pulmonary fibrosis model, with more prominent effects in a pro-fibrotic environment compared to pro-inflammatory. These results suggest that intracellular control using biomaterials has the potential to control macrophage phenotype post-administration, which is essential for successful macrophage cell therapy.

Cholangiocyte Organoids: The New Frontier in Regenerative Medicine for the Study and Treatment of Cholangiopathies.

Cholangiopathies include a group of chronic progressive disorders, affecting the cholangiocytes, the epithelial cells that line the biliary tree, leading to liver parenchymal fibrosis and eventually end-stage liver disease necessitating transplantation. Experimental modeling of these multifactorial cholestatic diseases faces challenges due to the lack of adequate experimental in vitro and in vivo models. A novel approach employs three-dimensional organoid systems that offer several advantages for modeling disease and testing drug response in vitro. Organoids mimic intercellular communication, replicate the architecture of organs, and maintain the cell's original phenotype. Cholangiocyte organoids provide an in vitro model to study the pathogenesis and pharmacotherapeutic treatment of cholangiopathies and show great promise for regenerative therapies. In particular, patient-derived organoids allow personalized medicine approaches and the study of individual disease characteristics. This review highlights the significance of cholangiocyte organoid models in advancing our understanding of cholangiopathies and driving advancements in regenerative medicine strategies.

Single-cell guided prenatal derivation of primary fetal epithelial organoids from human amniotic and tracheal fluids

Isolation of tissue-specific fetal stem cells and derivation of primary organoids is limited to samples obtained from termination of pregnancies, hampering prenatal investigation of fetal development and congenital diseases. Therefore, new patient-specific in vitro models are needed. To this aim, isolation and expansion of fetal stem cells during pregnancy, without the need for tissue samples or reprogramming, would be advantageous. Amniotic fluid (AF) is a source of cells from multiple developing organs. Using single-cell analysis, we characterized the cellular identities present in human AF. We identified and isolated viable epithelial stem/progenitor cells of fetal gastrointestinal, renal and pulmonary origin. Upon culture, these cells formed clonal epithelial organoids, manifesting small intestine, kidney tubule and lung identity. AF organoids exhibit transcriptomic, protein expression and functional features of their tissue of origin. With relevance for prenatal disease modeling, we derived lung organoids from AF and tracheal fluid cells of congenital diaphragmatic hernia fetuses, recapitulating some features of the disease. AF organoids are derived in a timeline compatible with prenatal intervention, potentially allowing investigation of therapeutic tools and regenerative medicine strategies personalized to the fetus at clinically relevant developmental stages.

Exploring regenerative medicine strategies for osteoporosis treatment: Progress, potential, and hurdles

A major worldwide health problem is osteoporosis, particularly in older people. There are restrictions on current therapies, such as anti-resorptive medications. Promising techniques including stem cell treatment, gene therapy, and growth factors are available in regenerative medicine. Preclinical and clinical research indicate promise for mesenchymal stem cells derived from bone marrow, adipose tissue, and umbilical cord blood. Enhancing bone regeneration with gene therapy that targets osteogenic factors such as BMPs is a promising approach. In order to mend bones, growth factors, cytokines, and scaffold materials are essential. Realising the benefits of regenerative medicine in treating osteoporosis requires cooperation and ongoing research, despite obstacles such limited clinical acceptability and regulatory barriers.

Bioprinting: Mechanical Stabilization and Reinforcement Strategies in Regenerative Medicine.

Bioprinting describes the printing of biomaterials and cell-laden or cell-free hydrogels with various combinations of embedded bioactive molecules. It encompasses the precise patterning of biomaterials and cells to create scaffolds for different biomedical needs. There are many requirements that bioprinting scaffolds face, and it is ultimately the interplay between the scaffold's structure, properties, processing, and performance that will lead to its successful translation. Among the essential properties that the scaffolds must possess - adequate and appropriate application-specific chemical, mechanical, and biological performance, the mechanical behavior of hydrogel-based bioprinted scaffolds is the key to their stable performance in vivo at the site of implantation. Hydrogels that typically constitute the main scaffold material and the medium for the cells and biomolecules are very soft and often lack sufficient mechanical stability, which reduces their printability and, therefore, the bioprinting potential. The aim of this review paper is to highlight the reinforcement strategies that are used in different bioprinting approaches to achieve enhanced mechanical stability of the bioinks and the printed scaffolds. Enabling stable and robust materials for the bioprinting processes will lead to the creation of truly complex and remarkable printed structures that could accelerate the application of smart, functional scaffolds in biomedical settings.

Recent Advances in Pharmaceutical Design: Unleashing the Potential of Novel Therapeutics.

Pharmaceutical design has made significant advancements in recent years, leading to the development of novel therapeutics with unprecedented efficacy and safety profiles. This review highlights the potential of these innovations to revolutionize healthcare and improve patient outcomes. The application of cutting-edge technologies like artificial intelligence, machine learning, and data mining in drug discovery and design has made it easier to find potential drug candidates. Combining big data and omics has led to the discovery of new therapeutic targets and personalized medicine strategies. Nanoparticles, liposomes, and microneedles are examples of advanced drug delivery systems that allow precise control over drug release, better bioavailability, and targeted delivery to specific tissues or cells. This improves the effectiveness of the treatment while reducing side effects. Stimuli-responsive materials and smart drug delivery systems enable drugs to be released on demand when specific internal or external signals are sent. Biologics and gene therapies are promising approaches in pharmaceutical design, offering high specificity and potency for treating various diseases like cancer, autoimmune disorders, and infectious diseases. Gene therapies hold tremendous potential for correcting genetic abnormalities, with recent breakthroughs demonstrating successful outcomes in inherited disorders and certain types of cancer. Advancements in nanotechnology and nanomedicine have paved the way for innovative diagnostic tools and therapeutics, such as nanoparticle-based imaging agents, targeted drug delivery systems, gene editing technologies, and regenerative medicine strategies. Finally, the review emphasizes the importance of regulatory considerations, ethical challenges, and future directions in pharmaceutical design. Regulatory agencies are adapting to the rapid advancements in the field, ensuring the safety and efficacy of novel therapeutics while fostering innovation. Ethical considerations regarding the use of emerging technologies, patient privacy, and access to advanced therapies also require careful attention.

Immunomodulatory Strategies for Cartilage Regeneration in Osteoarthritis.

Osteoarthritis (OA) is the most prevalent musculoskeletal disorder and a leading cause of disability globally. Although many efforts have been made to treat this condition, current tissue engineering (TE) and regenerative medicine strategies fail to address the inflammatory tissue environment that leads to the rapid progression of the disease and prevents cartilage tissue formation. First, this review addresses in detail the current anti-inflammatory therapies for OA with a special emphasis on pharmacological approaches, gene therapy, and mesenchymal stromal cell (MSC) intra-articular administration, and discusses the reasons behind the limited clinical success of these approaches at enabling cartilage regeneration. Then, we analyze the state-of-the-art TE strategies and how they can be improved by incorporating immunomodulatory capabilities such as the optimization of biomaterial composition, porosity and geometry, and the loading of anti-inflammatory molecules within an engineered structure. Finally, the review discusses the future directions for the new generation of TE strategies for OA treatment, specifically focusing on the spatiotemporal modulation of anti-inflammatory agent presentation to allow for tailored patient-specific therapies. Impact statement Osteoarthritis (OA) is a prevalent and debilitating musculoskeletal disorder affecting millions worldwide. Despite significant advancements in regenerative medicine and tissue engineering (TE), mitigating inflammation while simultaneously promoting cartilage tissue regeneration in OA remains elusive. In this review article, we discuss current anti-inflammatory therapies and explore their potential synergy with cutting-edge cartilage TE strategies, with a special focus on novel spatiotemporal and patient-specific anti-inflammatory strategies.

Neuromodulation to guide circuit reorganization with regenerative therapies in upper extremity rehabilitation following cervical spinal cord injury.

Spinal cord injury (SCI) is a profoundly debilitating condition with no effective treatment to date. The complex response of the central nervous system (CNS) to injury and its limited regeneration capacity pose bold challenges for restoring function. Cervical SCIs are the most prevalent and regaining hand function is a top priority for individuals living with cervical SCI. A promising avenue for addressing this challenge arises from the emerging field of regenerative rehabilitation, which combines regenerative biology with physical medicine approaches. The hypothesis for optimizing gains in upper extremity function centers on the integration of targeted neurorehabilitation with novel cell- and stem cell-based therapies. However, the precise roles and synergistic effects of these components remain poorly understood, given the intricate nature of SCI and the diversity of regenerative approaches. This perspective article sheds light on the current state of regenerative rehabilitation for cervical SCI. Notably, preclinical research has yet to fully incorporate rehabilitation protocols that mimic current clinical practices, which often rely on neuromodulation strategies to activate spared circuits below the injury level. Therefore, it becomes imperative to comprehensively investigate the combined effects of neuromodulation and regenerative medicine strategies in animal models before translating these therapies to individuals with SCI. In cases of severe upper extremity paralysis, the advent of neuromodulation strategies, such as corticospinal tract (CST) and spinal cord stimulation, holds promise as the next frontier in enhancing the effectiveness of cell- and stem cell-based therapies. Future preclinical studies should explore this convergence of neuromodulation and regenerative approaches to unlock new possibilities for upper extremity treatment after SCI.

Reprogramming methods for induced pluripotent stem cells generation

Regenerative medicine expects to replace the function of tissue or organs damaged by disease, trauma, or congenital issues. The tools used to realize these outcomes are tissue engineering and cellular therapies. Cellular therapy is considered a regenerative medicine strategy based on the use of stem cells. Pluripotent stem cells are the hotspots of cellular therapy due to their features that have been showed promising results. Embryonic stem cells (ESCs) are pluripotent, self-renewing cells that are derived from the inner cell mass (ICM) of the developing blastocyst. Pluripotency is the main feature that lead single cell to generate all cell lineages of the developing and adult organism. The use of human ESC (hESC) is ethically controversial, to overcome this problem the induced pluripotent stem cells (iPSCs) were developed. The aim of the present mini-review is to report a comprehensive summary of the different cellular reprogramming techniques from its initial conception to the present day.

Designing Hydrogels for Immunomodulation in Cancer Therapy and Regenerative Medicine.

The immune system not only acts as a defense against pathogen and cancer cells, but also plays an important role in homeostasis and tissue regeneration. Targeting immune systems is a promising strategy for efficient cancer treatment and regenerative medicine. Current systemic immunomodulation therapies are usually associated with low persistence time, poor targeting to action sites, and severe side effects. Due to their extracellular matrix-mimetic nature, tunable properties and diverse bioactivities, hydrogels are intriguing platforms to locally deliver immunomodulatory agents and cells, as well as provide an immunomodulatory microenvironment to recruit, activate, and expand host immune cells. In this review, the design considerations, including polymer backbones, crosslinking mechanisms, physicochemical nature, and immunomodulation-related components, of the hydrogel platforms, are focused on. The immunomodulatory effects and therapeutic outcomes in cancer therapy and tissue regeneration of different hydrogel systems are emphasized, including hydrogel depots for delivery of immunomodulatory agents, hydrogel scaffolds for cell delivery, and immunomodulatory hydrogels depending on the intrinsic properties of materials. Finally, the remained challenges in current systems and future development of immunomodulatory hydrogels are discussed.

Epitranscriptomic modifications in mesenchymal stem cell differentiation: advances, mechanistic insights, and beyond.

RNA modifications, known as the "epitranscriptome", represent a key layer of regulation that influences a wide array of biological processes in mesenchymal stem cells (MSCs). These modifications, catalyzed by specific enzymes, often termed "writers", "readers", and "erasers", can dynamically alter the MSCs' transcriptomic landscape, thereby modulating cell differentiation, proliferation, and responses to environmental cues. These enzymes include members of the classes METTL, IGF2BP, WTAP, YTHD, FTO, NAT, and others. Many of these RNA-modifying agents are active during MSC lineage differentiation. This review provides a comprehensive overview of the current understanding of different RNA modifications in MSCs, their roles in regulating stem cell behavior, and their implications in MSC-based therapies. It delves into how RNA modifications impact MSC biology, the functional significance of individual modifications, and the complex interplay among these modifications. We further discuss how these intricate regulatory mechanisms contribute to the functional diversity of MSCs, and how they might be harnessed for therapeutic applications. The review also highlights current challenges and potential future directions in the study of RNA modifications in MSCs, emphasizing the need for innovative tools to precisely map these modifications and decipher their context-specific effects. Collectively, this work paves the way for a deeper understanding of the role of the epitranscriptome in MSC biology, potentially advancing therapeutic strategies in regenerative medicine and MSC-based therapies.

Histological characteristics of hair follicles at different hair cycle and in vitro modeling of hair follicle-associated cells of yak (Bos grunniens).

To adapt to the extreme conditions of plateau environments, yaks have evolved thick hair, making them an ideal model for investigating the mechanisms involved in hair growth. We can gain valuable insights into how hair follicles develop and their cyclic growth in challenging environments by studying yaks. However, the lack of essential data on yak hair follicle histology and the absence of in vitro cell models for hair follicles serve as a limitation to such research objectives. In this study, we investigated the structure of skin tissue during different hair follicle cycles using the yak model. Additionally, we successfully established in vitro models of hair follicle-associated cells derived from yak skin, including dermal papilla cells (DPCs), preadipocytes, and fibroblasts. We optimized the microdissection technique for DPCs culture by simplifying the procedure and reducing the time required. Furthermore, we improved the methodology used to differentiate yak preadipocytes into mature adipocytes, thus increasing the differentiation efficiency. The introduction of yak as a natural model provides valuable research resources for exploring the mechanisms of hair growth and contributes to a deeper understanding of hair follicle biology and the development of regenerative medicine strategies.