Introduction:The therapeutic application of adipose-derived stem cells (ASCs) for wound healing has been reported. However, consistently controlling ASC secretory-factor levels, scaling up, and their mechanism of action have been poorly understood, which are critical steps for developing biological drugs to treat second-degree burns. Objective:Our goal is to develop a biological product, named consortia factors-δ2 (CFx-δ2), derived from cell-to-cell interactions between human immortalized ASCs using our patented technology and to evaluate the product consistency and in vitro biological effects to enhance the wound healing process. Methods:To assess product consistency, three batches of CFx-δ2 were analyzed and compared using immunomicroarray and metabolomics. The biological effects of these batches were studied using an in vitro wound healing assay and ex vivo human skin explants subjected to burn wounds. Anti-inflammatory effects were analyzed by inhibition of Nuclear Factor- κB (NF-κB) nuclear translocation in human dermal endothelial cells (HMEC-1). Finally, pro-angiogenesis was evaluated by the induction of tube-like structures and capillary networks in HMEC-1 cells promoted by CFx-δ2. Results:Our technology enabled the production of CFx-δ2 with enhanced efficiency and quality. When the three batches were compared, we found high consistency in the pattern and levels of cytokines as well as a strong correlation in the metabolite pattern. Accelerated wound healing was observed after in vitro and ex vivo wound treatment with CFx-δ2 in comparison to controls. The nuclear translocation of NF-κB, induced by Lipopolysaccharides (LPS), was 50% inhibited by CFx-δ2. Induction of more tube-like structures and networks was observed in endothelial cells treated with CFx-δ2 in comparison to controls. Discussion:These findings demonstrate that our technology is efficient to derive and scale up consistent levels of CFx-δ2 from immortalized adipose stem cells. The product accelerates wound healing by increasing fibroblast proliferation and migration, inhibiting inflammation, and promoting angiogenesis.
Introduction:Mesenchymal stem cells (MSCs) have a paracrine impact and may regenerate a variety of tissues. This represents a new prospect in cell-based stroke treatment. Several in vitro and in vivo investigations have demonstrated the neuroprotective and neurogenesis properties of MSCs and their secretome. Purpose:This review provides a comprehensive analysis of the therapeutic effects of MSCs and their secretome on stroke models in vitro and in vivo. Methods:A coverage evaluation is undertaken in accordance with PRISMA-ScR principles. The selection procedure includes the identification of items. Scopus site, PubMed and ScienceDirect, are used for in vitro and in vitro research, including electronic searches. The search terms include "ischemic stroke" or "MCAO", "MSC", "secretome", and "neurogenesis" or "angiogenesis". The searches are limited to English-language articles with full text availability. Results:After selecting 390 papers from two search engines, 94 publications satisfied the review criteria for using MSCs and secretomes for ischemic stroke treatment. We comprehensively review both in vitro and in vivo studies, analyzing aspects such as the source and treatment of MSCs and secretomes, as well as administration, dosage, and mechanisms of therapeutic effects in stroke models. Conclusion:MSC and secretome therapy for stroke have shown promising results in both in vitro and in vivo models. Exploration of alternative MSC sources, refining of isolation techniques, transfection of various proteins, and combination with herbal medicine are all efforts to improve the preclinical model. This work can be used as a reference for preclinical researchers to help with research design and translational research in clinical trials.
Background:Chronic tendon injuries often lead to diminished healing capacity, necessitating innovative treatments. Mesenchymal stem cells (MSCs) secretome has emerged as a promising option for enhancing tendon repair through paracrine signaling. This study evaluates the effectiveness of MSC secretome, derived from tendon-derived stem cells (TDSCs) and adipose-derived stem cells (ASCs) in healing chronic Achilles tendon injuries in a rat model. The focus is on Procollagen Type I N-Terminal Peptide (PINP) and Procollagen Type III N-Terminal Peptide (PIIINP) levels, and histopathological changes. Methods:Fourteen adult male rats were divided into four groups: Group I (TDSC secretome), Group II (ASC secretome), Group III (combination of TDSC and ASC secretome), and Group IV (control). The healing response was assessed through PINP and PIIINP immunoserological markers, and histopathological changes were analyzed. The study adhered to ARRIVE and ICLAS guidelines and followed the National Institutes of Health (NIH) Guide for the Care and Use of Laboratory Animals. Results:The combination group showed significantly higher PINP levels compared to the control group (p = 0.004), suggesting enhanced Type I collagen synthesis. However, no significant differences in PIIINP levels were observed among the groups. Histopathological analysis showed no significant differences in collagen alignment or angiogenesis between treatment and control groups. Conclusion:The MSC secretome, particularly the combination of TDSCs and ASCs, may accelerate collagen Type I synthesis and improve tendon microstructure. This suggests their potential for treating chronic tendon injuries. However, further research with longer observation periods and clinical trials is crucial to confirm these findings and advance our understanding of tendon healing.
The mammalian oocyte is pivotal in reproductive biology, acting as a central hub for cellular reprogramming and stemness. It uniquely contributes half of the zygotic nuclear genome and the entirety of the mitochondrial genome, ensuring individual development and health. Oocyte-mediated reprogramming, exemplified by nuclear transfer, resets somatic cell identity to achieve pluripotency and has transformative potential in regenerative medicine. This process is critical for understanding cellular differentiation, improving assisted reproductive technologies, and advancing cloning and stem cell research. During fertilization, the maternal-zygotic transition shifts developmental control from maternal factors to zygotic genome activation, establishing totipotency. Oocytes also harbor reprogramming factors that guide nuclear remodeling, epigenetic modifications, and metabolic reprogramming, enabling early embryogenesis. Structures like mitochondria, lipid droplets, and cytoplasmic lattices contribute to energy production, molecular regulation, and cellular organization. Recent insights into oocyte components, such as ooplasmic nanovesicles and endolysosomal vesicular assemblies (ELVAS), highlight their roles in maintaining cellular homeostasis, protein synthesis, and reprogramming efficiency. By unraveling the reprogramming mechanisms inherent in oocytes, we advance our understanding of cloning, cell differentiation, and stem cell therapy, highlighting their valuable significance in developmental biology and regenerative medicine.
Objective: Chronic wounds are a common clinical problem that necessitate the exploration of novel regenerative therapies. We report a method to investigate the in vitro wound healing capacity of an innovative biomaterial, which is based on amniotic membrane- derived stem cells (AMSCs) embedded in an alginate hydrogel matrix. The aim of this study was to prepare an sodium alginate-based hydrogel, cross-linked calcium chloride (CaCl2) with the active ingredient AMSC (AMSC/Alg-H) and to evaluate its in vitro effectiveness for wound closure. Methods: This hydrogel preparation involved combining sterile solutions of AMSC, sodium alginate, and CaCl2, followed by rinsing with serum-free media. The cells were cultured in different 6-well plates, namely sodium alginate, calcium chloride, AMSC, Alg-H, and AMSC/Alg-H, in complete medium with 10% FBS. The hydrogel was successfully formulated, as confirmed by characterization techniques including Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR) spectroscopy, Differential Scanning Calorimetry (DSC), Cytotoxicity Studies, TGF-beta 1 Level Measurement by ELISA, and Cell Scratch Wound Assay. Results: Cryo-EM characterization of the Alg-H preparation successfully demonstrated the encapsulation of MSCs. FTIR and DSC analyses indicate that crosslinking transpires in Alg-H encapsulating AMSC. The AMSC/Alg-H preparation showed no significant difference in toxicity compared to HaCaT cells (p < 0.05), indicating it was not toxic to HaCaT cells. Furthermore, in the scratch wound assay test at 24 hours, the AMSC/Alg-H preparation achieved 100% wound closure, outperforming both AMSC and Alg-H alone. In vitro assessment revealed that AMSC/Alg-H significantly enhanced key wound healing processes, including cell proliferation and migration, compared to Alg-H. Conclusion: Our study demonstrated the promising potential of AMSC/Alg-H as an enhanced regenerative therapy for in vitro wound healing. AMSC/Alg-H was able to maintain the viability of AMSCs and facilitate the formation of tissue-like structures.
Biobanking has emerged as a transformative concept in advancing the medical field, particularly with the exponential growth of umbilical cord (UC) biobanking in recent decades. UC blood and tissue provide a rich source of primitive hematopoietic stem cells (HSCs) and mesenchymal stem cells (MSCs) for clinical transplantation, offering distinct advantages over alternative adult stem cell sources. However, to fully realize the therapeutic potential of UC-derived stem cells and establish a comprehensive global UC-biobanking network, it is imperative to optimize and standardize UC processing, cryopreservation methods, quality control protocols, and regulatory frameworks, alongside developing effective consent provisions. This review aims to comprehensively explore recent advancements in UC biobanking, focusing on the establishment of rigorous safety and quality control procedures, the standardization of biobanking operations, and the optimization and automation of UC processing and cryopreservation techniques. Additionally, the review examines the expanded clinical applications of UC stem cells, addresses the challenges associated with umbilical cord biobanking and UC-derived stem cell therapies, and discusses the promising role of artificial intelligence (AI) in enhancing various operational aspects of biobanking, streamlining data processing, and improving data analysis accuracy while ensuring compliance with safety and quality standards. By addressing these critical areas, this review seeks to provide insights into the future direction of UC biobanking and its potential to significantly impact regenerative medicine.
Background and Objective: Non-obstructive azoospermia (NOA) is an important cause of male infertility. This study is being proposed to assess the efficacy of autologous bone marrow-derived mesenchymal stem cells (MSCs) in the reversal of busulfaninduced NOA in rats. Methods: Twenty adult 3-month-old male rats were divided into two groups: a control group and a study group. In the study group, bone marrow was aspirated to culture MSCs. NOA was created by stopping endogenous spermatogenesis in all the animals by injecting two doses of busulfan 10 mg/kg body weight with a 3 week interval. Four weeks after the last dose of busulfan, two animals were euthanized and the testes were studied histologically to confirm complete azoospermia. In the study group, five million MSCs in 1 mL normal saline were injected into seminiferous tubules; and in the control group, 1 mL of normal saline was injected. After 4 weeks of MSC injection, all the rats were euthanized and epididymis tails and testes were harvested and sent for measurement of serological indices, including luminal, cellular, and total diameters, luminal, cellular, and cross-sectional areas, number of tubules per unit area of testis, numerical density of the tubules, and spermatogenesis index, pre- and post-MSC transplantation. Results: The effect of busulfan on the testicular tissue was universally devastating. In the control group, there was variable length and width of markedly necrotic seminiferous tubules, whereas in the group treated with autologous bone marrow-derived MSCs there was variable height of germinal epithelium in seminiferous tubules, with active spermatogenesis, showing spermatogonia, spermatocytes, and sperm. Conclusion: MSC injection in the testis has the potential to reverse the testicular function of spermatogenesis after cytotoxic therapy. Human trials should be undertaken to confirm our findings and bring the results into clinical practice.
Introduction:Mesenchymal stem/stromal cells (MSCs)-based products have unique characteristics compared to other drugs because of their inherently variable effects depending on culture conditions and microenvironment. In some cases, cells can be produced individually, one batch at a time, for personalized therapy. Therefore, it is very important to optimize both culture conditions and medium composition under Good Manufacturing Practice (GMP) standards. MSCs properties have been exploited as potential cell therapies in regenerative medicine. The main mechanism of their protective and regenerative effect is based on their secretory activity. Simultaneously, their secretome is highly variable and sensitive to any change in environmental conditions. Depending on the type of damage and the target application, it is desirable to enhance the secretion of therapeutic factors. Changes in the modulation of environmental conditions can affect survival, migration ability, and both proliferative and clonogenic potentials. Materials and Methods:This study cultured Wharton's jelly-derived MSCs (WJ-MSCs) in media with varying concentrations of human platelet lysate (hPL). Two groups were created: one with low hPL concentration and another with a high hPL concentration. The effects of these different hPL concentrations were analyzed by assessing mesenchymal phenotype retention, secretory activity, clonogenic potential, proliferation, and migration capabilities. Additionally, the secretion levels of key therapeutic factors, such as Hepatocyte Growth Factor (HGF), Brain-Derived Neurotrophic Factor (BDNF), and Chemokine Ligand 2 (CCL-2), were measured. Results:WJ-MSCs maintained their mesenchymal phenotype regardless of hPL concentration. However, a higher concentration of hPL promoted cell clonogenic potential, proliferation, migration, and increased secretion of therapeutic factors. Conclusion:Adjusting the hPL concentration in the culture medium modulates the response of WJ MSCs and enhances their therapeutic potential. Higher hPL concentration promotes increased secretory activity and improves the regenerative capacity of WJ-MSCs, suggesting a promising strategy to optimize MSC-based therapies.
Ayatulloh Alquraisy,1 Gofarana Wilar,2 Ahmed Fouad Abdelwahab Mohammed,3 Ali El-Rayyes,4 Cecep Suhandi,1 Nasrul Wathoni1 1Department of Pharmaceutics and Pharmaceutical Technology, Faculty of Pharmacy, University of Padjadjaran, Sumedang, 45363, Indonesia; 2Department of Pharmacology and Clinical Pharmacy, Faculty of Pharmacy, University of Padjadjaran, Sumedang, 45363, Indonesia; 3Department of Pharmaceutics, Faculty of Pharmacy, Minia University, Minia, 61519, Egypt; 4Department of Chemistry, College of Science, Northern Border University, Arar, Saudi ArabiaCorrespondence: Nasrul Wathoni, Email nasrul@unpad.ac.idAbstract: Various studies have been widely conducted on conditioned medium for the development of anti-aging preparations, including the utilization of stem cells, which present a promising alternative solution. This narrative review aims to understand the latest developments in various conditioned medium stem cell applications for anti-aging on the skin. A search of the Scopus database yielded publications of interest. The research focused on articles published without restrictions on the year. After finding 68 articles in the search results, they moved on to the checking phase. Upon comprehensive literature review, 23 articles met the inclusion criteria, while 45 articles were deemed ineligible for participation in this research. The results of the review indicate that conditioned medium from various stem cells has demonstrated success in reducing risk factors for skin aging, as proven in various tests. The successful reduction of the risk of skin aging has been established in vitro, in vivo, and in clinical trials. Given the numerous studies on the progress of exploring and utilizing conditioned medium, it is expected to provide a solution to the problem of skin aging.Keywords: conditioned medium, stem cell, anti-aging, skin aging
Rilianawati,1 Ratih Rinendyaputri,2,3 Yoggi Ramadhani Purwaningtyas2 1Vaccine and Drug Research Center, National Research and Innovation Agency, Serpong, Indonesia; 2Center for Biomedical Research, Research Organization for Health, National Research and Innovation Agency, Bogor, Indonesia; 3Graduate School of Biomedical, Sciences, Doctoral Program, Faculty of Medicine, Universitas Padjadjaran, Bandung, IndonesiaCorrespondence: Rilianawati, Email rili001@brin.go.id
Wanjala Ferdinand Nang’ole Department of Surgery, University of Nairobi, Nairobi, KenyaCorrespondence: Wanjala Ferdinand Nang’ole, Department of Surgery, University of Nairobi, PO Box 30197-00100, Nairobi, Kenya, Tel +254-71-4342-214, Email nangole2212@gmail.com
Aim:The relationship between ligaments and bone is a complex and heterogeneous junction involving bone, mineralized fibro cartilage, non-mineralized fibro cartilage and ligaments. Mesenchymal stem cells (MSC) can be used in vivo to control inflammation and aid in tissue repair, according to studies. This review focused on using exosomes as an alternative to MSC, as a cell-free therapy for modulating the remodelling process.Methods:To conduct a systematic review of the literature, the phrases "exosome" and "ligament" or "tendon" and "extracellular vesicle" and "stem cells" were used as the search keywords in PubMed (MEDLINE), OVID, the Cochrane Library, and Science Direct. From the literature, 73 studies in all were found. Six studies were included in this systematic review after full-text evaluation.Results:Six included studies covered a range of MSC types, isolation techniques, animal models, and interventions. Biomechanical results consistently indicated the beneficial impact of conditioned media, vesicles, and exosomes on treating tendons and ligaments. Noteworthy findings were the reduction of inflammation by iMSC-IEVs, chondrocyte protection by iPSC-EVs (extracellular vesicles generated by inflammation-primed adipose-derived stem cells), osteolysis treatment using DPSC-sEVs (small extracellular vesicles derived from dental pulp stem cells), and the contribution of exosome-educated macrophages to ligament injury wound healing.Conclusion:Exosomes may serve as a cell-free therapeutic substitute for modulating the remodelling process, particularly in ligament healing.
Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive lung disease with no known cure, characterized by the formation of scar tissue in the lungs, leading to respiratory failure. Although the exact cause of IPF remains unclear, the condition is thought to result from a combination of genetic and environmental factors. One of the most widely used animal models to study IPF is the bleomycin-induced lung injury model in mice. In this model, the administration of the chemotherapeutic agent bleomycin causes pulmonary inflammation and fibrosis, which closely mimics the pathological features of human IPF. Numerous recent investigations have explored the functions of various categories of stem cells in the healing process of lung injury induced by bleomycin in mice, documenting the beneficial effects and challenges of this approach. Differentiation of stem cells into various cell types and their ability to modulate tissue microenvironment is an emerging aspect of the regenerative therapies. This review article aims to provide a comprehensive overview of the role of stem cells in repairing bleomycin-induced lung injury. It delves into the mechanisms through which various types of stem cells, including mesenchymal stem cells, embryonic stem cells, induced pluripotent stem cells, and lung resident stem cells, exert their therapeutic effects in this specific model. We have also discussed the unique set of intermediate markers and signaling factors that can influence the proliferation and differentiation of alveolar epithelial cells both during lung repair and homeostasis. Finally, we highlight the challenges and opportunities associated with translating stem cell therapy to the clinic for IPF patients. The novelty and implications of this review extend beyond the understanding of the potential of stem cells in treating IPF to the broader field of regenerative medicine. We believe that the review paves the way for further advancements in stem cell therapies, offering hope for patients suffering from this debilitating and currently incurable disease.
Objectives: To assess the effectiveness of adipocyte-derived mesenchymal stem cells-conditioned media (ADSC-CM) formulation in telogen efiuvium patients.Methods: A retrospective cohort study was conducted at a dermatology clinic in Jeddah, Saudi Arabia. The study included 50 consecutive patients aged 20-70 years, who were diagnosed with telogen efiuvium. All patients received five monthly sessions of the same commercial ADSC-CM formulation, using a standardized application protocol. Pre-and post-intervention changes in trichometry parameters were analyzed.Results: There was a significant increase in mean hair density (up to 29.01 hair/cm(2); effect size 0.7-1.0), cumulative hair thickness (up to 2.67 units; effect size 0.7-1.4), and the number of follicular hair units (up to 19.96%; effect size 1.0-1.3) in all scalp regions (p < 0.001), associated with a decrease in mean trichometry-derived Sinclair scale by 0.8-1.3 (p < 0.001). Positive outcomes were observed in 70%-92% of the patients depending on the parameter and scalp region. There was no impact of the patient's age on ADSC-CM efficacy. Conclusion: ADSC-CM was successfully applied as a new treatment option for patients with telogen efiuvium. These findings provide another therapeutic and research area for dermatologists to optimize the management of telogen efiuvium and reduce its impact on patients.
Purpose:Two-dimensional (2D)-based cell culture systems, limited by their inherent heterogeneity and scalability, are a bottleneck in the production of high-quality cells for downstream biomedical applications. Finding the optimal conditions for large-scale stem cell culture while maintaining good cellular status is challenging. The aim of this study was to assess the effects of three-dimensional (3D) culture on the viability, proliferation, self-renewal, and differentiation of human induced pluripotent stem cells (IPSCs).Patients and Methods:Various culture conditions were evaluated to determine the optimal conditions to maintain the viability and proliferation of human IPSCs in a 3D environment: static versus dynamic culture, type of adhesion protein added to alginate (Matrigel™ versus gelatin), and the addition of Y-27632t on long-term 3D culture. The proliferation ability of the cells was evaluated via the MTS proliferation assay; the expression levels of the pluripotency markers Nanog and Oct3/4, PAX6 as an ectoderm marker, and laminin-5 and fibronectin as markers of extracellular matrix synthesis were assessed; and HIF1α and HIF2α levels were measured using quantitative reverse transcription polymerase chain reaction.Results:Using a high-aspect-ratio vessel bioreactor with a gentle, low-sheer, and low-turbulence environment with sufficient oxygenation and effective mass transfer of nutrients and waste, we verified its ability to promote cell proliferation and self-renewal. The findings showed that human IPSCs have the ability to maintain pluripotency in a feeder-free system and by inhibiting ROCK signaling and using hypoxia to improve single-cell viability in 3D culture. Furthermore, these cells demonstrated increased self-renewal and proliferation when inoculated as single cells in 3D alginate beads by adding RI during the culture period.Conclusion:Dynamic 3D culture is desirable for the large-scale expansion of undifferentiated human IPSCs.
Introduction: Cells collected from Wharton's jelly are a rich source of mesenchymal stem cells. They can be easily obtained and grown using the adhesive method. They produce many types of proteins, including VEGF. Their role is to participate in angiogenesis, vasodilation, stimulation of cells to migrate, and chemotactic activity. The aim of this study was to evaluate expression of genes from the vascular endothelial growth factor family: VEGFA, VEGFB and VEGFC in MSC and the analysis of dependence of the expression of the studied genes on clinical factors related to the course of pregnancy and childbirth, and health of mother and child. Material and Methods: The research material was an umbilical cord obtained from 40 patients hospitalized in the Department of Obstetrics and Pathology of Pregnancy of the Independent Public Clinical Hospital No.1 in Lublin. The age of the women was 21-46, all gave birth by cesarean section. Some of the patients suffered from hypertension and hypothyroidism. Material collected from patients immediately after delivery was subjected to enzymatic digestion with type I collagenase. The isolated cells were then cultured in adherent conditions, and then gene expression was assessed using qPCR and the immunophenotype of the cells was assessed cytometrically. Results: Conducted studies have shown significant differences in expression of VEGF family genes depending on clinical condition of mother and child. Significant differences in VEGF-family gene expression level in umbilical cord MSC collected from women with hypothyroidism, hypertension, time of labor and birth weight of the baby were shown. Conclusion: Probably due to hypoxia (caused, for example, by hypothyroidism or hypertension), the MSCs found in the umbilical cord may react with an increased expression of VEGF and a compensatory increase in the amount of secreted factor, the aim of which is, i.a., vasodilation and increase of blood supply to the fetus through the umbilical vessels.
Cancer continues to rank among the world's leading causes of mortality despite advancements in treatment. Cancer stem cells, which can self-renew, are present in low abundance and contribute significantly to tumor recurrence, tumorigenicity, and drug resistance to various therapies. The drug resistance observed in cancer stem cells is attributed to several factors, such as cellular quiescence, dormancy, elevated aldehyde dehydrogenase activity, apoptosis evasion mechanisms, high expression of drug efflux pumps, protective vascular niche, enhanced DNA damage response, scavenging of reactive oxygen species, hypoxic stability, and stemness-related signaling pathways. Multiple studies have shown that mitochondria play a pivotal role in conferring drug resistance to cancer stem cells, through mitochondrial biogenesis, metabolism, and dynamics. A better understanding of how mitochondria contribute to tumorigenesis, heterogeneity, and drug resistance could lead to the development of innovative cancer treatments.
Background This study aimed to investigate the effects of hypoxia and normoxia preconditioning in rabbit intervertebral disc-derived stem cells (IVDSCs) and discus-derived conditioned medium (DD-CM)/secretomes in vitro. Transforming growth factor (TGF)-β1, platelet-derived growth factor (PDGF), fibroblast growth factor (FGF), and vascular endothelial growth factor (VEGF) have a role in the proliferation, development, differentiation, and migration of MSCs. Materials and Methods Intervertebral discs were isolated from rabbit and incubated in normoxia and hypoxia 1%, 3%, and 5% (hypoxia groups) condition. Cell counting was performed after 24 hours of manipulation, then analyzed using one-way ANOVA. TGF-β1, PDGF, FGF, and VEGF were measured using the ELISA. Results The highest number of cells was in the hypoxia 3% preconditioning compared to the normoxia, hypoxia 1%, and hypoxia 5% groups. Hypoxia 3% also had the highest increase in PDGF protein production compared to normoxia, with hypoxia 1% and 5%. Among hypoxia groups, the highest secretions of VEGF and FGF proteins were in the hypoxia 3% group. Based on TGF-β1 protein measurement, the hypoxia 1% group was the highest increase in this protein compared to other groups. Conclusion Oxygen level in hypoxia preconditioning has a role in the preparation of IVDSCs and secretome preparation in vitro. The highest cell numbers were found in the treatment group with 3% hypoxia, and 3% hypoxia was significantly related to support IVDSCs preparation. Preconditioning with 3% hypoxia had higher PDGF and VEGF levels than other hypoxia groups.
