Human Serum Is an Advantageous Supplement for Human Dermal Fibroblast Expansion: Clinical Implications for Tissue Engineering of Skin

Fabrication and Characterization of an Electro-Compacted Collagen/Elastin/Hyaluronic Acid Sheet as a Potential Skin Scaffold

The development of biomimetic structures with integrated extracellular matrix (ECM) components represents a promising approach to biomaterial fabrication. Here, an artificial ECM, comprising the structural protein collagen I and elastin (ELN), as well as the glycosaminoglycan hyaluronan (HA), is reported. Specifically, collagen and ELN are electrochemically aligned to mimic the compositional characteristics of the dermal matrix. HA is incorporated into the electro-compacted collagen-ELN matrices via adsorption and chemical immobilization, to give a final composition of collagen/ELN/HA of 7:2:1. This produces a final collagen/ELN/hyaluronic acid scaffold (CEH) that recapitulates the compositional feature of the native skin ECM. This study analyzes the effect of CEH composition on the cultivation of human dermal fibroblast cells (HDFs) and immortalized human keratinocytes (HaCaTs). It is shown that the CEH scaffold supports dermal regeneration by promoting HDFs proliferation, ECM deposition, and differentiation into myofibroblasts. The CEH scaffolds are also shown to support epidermis growth by supporting HaCaTs proliferation, differentiation, and stratification. A double-layered epidermal-dermal structure is constructed on the CEH scaffold, further demonstrating its ability in supporting skin cell function and skin regeneration.

Quality management overview for the production of a tissue-engineered human skin substitute in Malaysia

Treatments for skin injuries have recently advanced tremendously. Such treatments include allogeneic and xenogeneic transplants and skin substitutes such as tissue-engineered skin, cultured cells, and stem cells. The aim of this paper is to discuss the general overview of the quality assurance and quality control implemented in the manufacturing of cell and tissue product, with emphasis on our experience in the manufacturing of MyDerm®, an autologous bilayered human skin substitute. Manufacturing MyDerm® requires multiple high-risk open manipulation steps, such as tissue processing, cell culture expansion, and skin construct formation. To ensure the safety and efficacy of this product, the good manufacturing practice (GMP) facility should establish a well-designed quality assurance and quality control (QA/QC) programme. Standard operating procedures (SOP) should be implemented to ensure that the manufacturing process is consistent and performed in a controlled manner. All starting materials, including tissue samples, culture media, reagents, and consumables must be verified and tested to confirm their safety, potency, and sterility. The final products should also undergo a QC testing series to guarantee product safety, efficacy, and overall quality. The aseptic techniques of cleanroom operators and the environmental conditions of the facility are also important, as they directly influence the manufacturing of good-quality products. Hence, personnel training and environmental monitoring are necessary to maintain GMP compliance. Furthermore, risk management implementation is another important aspect of QA/QC, as it is used to identify and determine the risk level and to perform risk assessments when necessary. Moreover, procedures for non-conformance reporting should be established to identify, investigate, and correct deviations that occur during manufacturing. This paper provides insight and an overview of the QA/QC aspect during MyDerm® manufacturing in a GMP-compliant facility in the Centre for Tissue Engineering and Regenerative Medicine, Faculty of Medicine, Universiti Kebangsaan Malaysia.

The dark side of foetal bovine serum in extracellular vesicle studies

Extracellular vesicles (EVs) have been shown to be involved in cell-cell communication and to take part in both physiological and pathological processes. Thanks to their exclusive cargo, which includes proteins, lipids, and nucleic acids from the originating cells, they are gaining interest as potential biomarkers of disease. In recent years, their appealing features have been fascinating researchers from all over the world, thus increasing the number of in vitro studies focused on EV release, content, and biological activities. Cultured cell lines are the most-used source of EVs; however, the EVs released in cell cultures are influenced by the cell culture conditions, such as the use of foetal bovine serum (FBS). FBS is the most common supplement for cell culture media, but it is also a source of contaminants, such as exogenous bovine EVs, RNA, and protein aggregates, that can contaminate the cell-derived EVs and influence their cargo composition. The presence of FBS contaminants in cell-derived EV samples is a well-known issue that limits the clinical applications of EVs, thus increasing the need for standardization. In this review, we will discuss the pros and cons of using FBS in cell cultures as a source of EVs, as well as the protocols used to remove contaminants from FBS.

Allogeneic Dermal Fibroblasts Improve Tendon-to-Bone Healing in a Rabbit Model of Chronic Rotator Cuff Tear Compared With Platelet-Rich Plasma

PURPOSE

To compare the effects of allogeneic dermal fibroblasts (ADFs) and platelet-rich plasma (PRP) on tendon-to-bone healing in a rabbit model of chronic rotator cuff tear.

METHODS

Thirty-two rabbits were divided into 4 groups (8 per group). In 2 groups, the supraspinatus tendon was detached and was left as such for 6 weeks. At 6 weeks after creating the tear model, we performed transosseous repair with 5 × 10⁶ ADFs plus fibrin injection in the left shoulder and PRP plus fibrin in the right shoulder. The relative expression of the COL1, COL3, BMP2, SCX, SOX9, and ACAN genes was assessed at 4 weeks (group A) and 12 weeks (group B) after repair. Histologic and biomechanical evaluations of tendon-to-bone healing at 12 weeks were performed with ADF injection in both shoulders in group C and PRP injection in group D.

RESULTS

At 4 weeks, COL1 and BMP2 messenger RNA expression was higher in ADF-injected shoulders (1.6 ± 0.8 and 1.0 ± 0.3, respectively) than in PRP-injected shoulders (1.0 ± 0.3 and 0.6 ± 0.3, respectively) (P = .019 and P = .013, respectively); there were no differences in all genes in ADF- and PRP-injected shoulders at 12 weeks (P > .05). Collagen continuity, orientation, and maturation of the tendon-to-bone interface were better in group C than in group D (P = .024, P = .012, and P = .013, respectively) at 12 weeks, and mean load to failure was 37.4 ± 6.2 N/kg and 24.4 ± 5.2 N/kg in group C and group D, respectively (P = .015).

CONCLUSIONS

ADFs caused higher COL1 and BMP2 expression than PRP at 4 weeks and showed better histologic and biomechanical findings at 12 weeks after rotator cuff repair of the rabbit model. ADFs enhanced healing better than PRP in the rabbit model.

CLINICAL RELEVANCE

This study could serve as a transitional study to show the effectiveness of ADFs in achieving tendon-to-bone healing after repair of chronic rotator cuff tears in humans.

Safety and Efficacy of Autologous Dermal Fibroblast Injection to Enhance Healing After Full-Thickness Rotator Cuff Repair: First-in-Human Pilot Study

Background:

There is growing interest in various biological supplements to improve tendon healing in patients after arthroscopic rotator cuff repair. The ideal biological supplement to strengthen rotator cuff remains unknown.

Purpose:

To assess the safety and efficacy of autologous cultured dermal fibroblast (ADF) injection on tendon-to-bone healing in patients after arthroscopic rotator cuff repair.

Study Design:

Case series; Level of evidence, 4.

Methods:

Included were 6 patients who underwent arthroscopic rotator cuff repair between June 2018 and March 2020; all patients had a full-thickness rotator cuff tear (>2 cm) involving the supraspinatus and infraspinatus tendons. The patients were injected with ADF between the repaired tendon and footprint during arthroscopic rotator cuff repair using the suture bridge technique. The safety of ADFs and the procedure was evaluated at 5 weeks postoperatively, and the anatomical healing of the repaired tendon was accessed at 6 months postoperatively using magnetic resonance imaging and at 12 months using ultrasonography. Outcomes including shoulder range of motion (ROM), visual analog scale (VAS) for pain, and functional scores were measured at 6 and 12 months postoperatively.

Results:

Adverse reactions to ADF injection were not observed at 6 months after surgery. VAS and functional scores at 6 and 12 months postoperatively were significantly improved compared with preoperative scores (all P < .05). However, there was no significant difference on any ROM variable between preoperative and postoperative measurements at 6 and 12 months (all P > .05). No healing failure was found at 6 and 12 months postoperatively.

Conclusion:

There was no adverse reaction to ADF injection, and all patients had successful healing after rotator cuff repair. A simple and easily accessible ADF injection may be a novel treatment option for increasing the healing capacity of torn rotator cuff tendons. Further clinical research is needed to verify the study results.

Engineering Advanced In Vitro Models of Systemic Sclerosis for Drug Discovery and Development

Systemic sclerosis (SSc) is a complex multisystem disease with the highest case-specific mortality among all autoimmune rheumatic diseases, yet without any available curative therapy. Therefore, the development of novel therapeutic antifibrotic strategies that effectively decrease skin and organ fibrosis is needed. Existing animal models are cost-intensive, laborious and do not recapitulate the full spectrum of the disease and thus commonly fail to predict human efficacy. Advanced in vitro models, which closely mimic critical aspects of the pathology, have emerged as valuable platforms to investigate novel pharmaceutical therapies for the treatment of SSc. This review focuses on recent advancements in the development of SSc in vitro models, sheds light onto biological (e.g., growth factors, cytokines, coculture systems), biochemical (e.g., hypoxia, reactive oxygen species) and biophysical (e.g., stiffness, topography, dimensionality) cues that have been utilized for the in vitro recapitulation of the SSc microenvironment, and highlights future perspectives for effective drug discovery and validation.

Let's Talk About Sex-Biological Sex Is Underreported in Biomaterial Studies

Precision medicine aims to better individualize healthcare. It requires that biomaterials be designed for the physiological characteristics of a specific patient. To make this a reality, biomaterials research and development must address differences of biological sex. More specifically, biomaterials should be designed with properties optimized and appropriate for male and female patients. In analyzing research articles from seven prominent biomaterials journals, sex as a biological variable is missing from an overwhelming majority of in vitro biomaterial studies. From the survey, the reporting of the sex of primary cell cultures happened only 10.3% of the time. Contributing to this trend is that commercial vendors bias cell lines toward one sex or another by not disclosing information of cell line sex at the time of purchase; researchers do not communicate this pertinent information in published studies; and many journal policies have little to no requirements for reporting cell line characteristics. Omitting this valuable information leads to a gap in the understanding of sex-specific cell-biomaterial interactions and it creates a bias in research findings towards one sex or another. To curb this concerning trend and make precision biomaterials a reality will require the biomaterials field to "talk about sex" by reporting cell sex more broadly.

Macrophages significantly enhance wound healing in a vascularized skin model

Tissue-engineered dermo-epidermal skin grafts could be applied for the treatment of large skin wounds or used as an in vitro wound-healing model. However, there is currently no skin replacement model that includes both, endothelial cells to simulate vascularization, and macrophages to regulate wound healing and tissue regeneration. Here, we describe for the first time a tissue-engineered, fully vascularized dermo-epidermal skin graft based on a fibrin hydrogel scaffold, using exclusively human primary cells. We show that endothelial cells and human dermal fibroblasts form capillary-like structures within the dermis whereas keratinocytes form the epithelial cell layer. Macrophages played a key role in controlling the number of epithelial cells and their morphology after skin injury induced with a CO₂ laser. The activation of selected cell types was confirmed by mRNA analysis. Our data underline the important role of macrophages in vascularized skin models for application as in vitro wound healing models or for skin replacement therapy. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 1340-1350, 2019.

Effects of Allogenic Dermal Fibroblasts on Rotator Cuff Healing in a Rabbit Model of Chronic Tear

BACKGROUND

The failure of rotator cuffs to heal after repair is an unresolved surgical issue. There have been substantial efforts, including the use of biological supplements, to enhance tendon healing. Dermal fibroblasts are a good candidate for tendon tissue engineering because they are similar to the tenocytes used for collagen synthesis. In addition, they are easily accessible because autologous dermal fibroblasts can be obtained from individual skin without major skin defects and allogenic dermal fibroblasts (ADFs) have already been commercialized in the field of skin engineering.

PURPOSE

To determine the effects of dermal fibroblasts on tendon-to-bone healing in a rabbit model of a chronic rotator cuff tear.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 33 rabbits were randomly allocated into 3 groups (n = 11 each). Supraspinatus tendons were detached and left for 6 weeks to establish a chronic rotator tear model. Torn tendons were repaired in a transosseous manner with the injection of 5 × 10⁶ ADFs with fibrin in group A, fibrin only in group B, and saline only in group C. At 12 weeks after repair, the mechanical test and histological evaluation were performed.

RESULTS

Seven rabbits died before the evaluation (1 in group A, 2 in group B, 4 in group C). In the final evaluation, the mean ± SD load to failure was 48.1 ± 13.3 N/kg for group A, 34.5 ± 8.9 N/kg for group B, and 31.1 ± 8.3 N/kg for group C, and group A showed significantly higher load-to-failure values than the other groups ( P = .011). The midsubstance tear rate, which presented stronger tendon-to-bone healing than insertional tear, was 50.0% in group A, 22.2% in group B, 28.6% in group C, but the differences were not statistically significant ( P = .413). In the histological evaluation, group A showed greater collagen fiber continuity and better orientation than the other groups.

CONCLUSION

This controlled laboratory study verified, on the basis of biomechanics and histology, the potential for the use of ADFs in rotator cuff healing. The current results suggest a new biological supplement to increase the rate of rotator cuff healing.

CLINICAL RELEVANCE

The most important finding of this study was the potential for a new biological supplement to enhance rotator cuff healing-a continuing challenge.

Correcting Nasojugal Groove with Autologous Cultured Fibroblast Injection: A Pilot Study

BACKGROUND

A new commercial drug that contains autologous cultured fibroblasts has been developed and approved by the United States Food and Drug Administration for improving the appearance of nasolabial folds. However, the treatment requires three sessions every 3-6 weeks. It is known that the skin overlying the nasojugal groove is thinner, and the wrinkle is generally shallower than nasolabial folds. Therefore, we hypothesized that the nasojugal groove could be improved by just one treatment session. Therefore, the purpose of this study was to evaluate the efficacy and safety of autologous cultured fibroblast injection to correct nasojugal grooves.

METHODS

Forty-six subjects with nasojugal grooves were enrolled in this study. They were injected with autologous cultured fibroblasts or placebo in one session. Blinded evaluators and subjects assessed the efficacy using a validated wrinkle assessment scale at 4, 12, and 24 weeks after the injection. Information of adverse events was collected at each visit.

RESULTS

Based on the evaluators' assessment at 24 weeks after the injection, 76% of subjects treated with autologous cultured fibroblasts showed improvement whereas 0% of subjects treated with placebo showed improvement (P < 0.0001). Based on self-assessment at 24 weeks after the injection, 72% of subjects treated with autologous cultured fibroblasts and 45% of subjects treated with placebo showed improvement (P = 0.0662). There were no serious adverse events related to autologous cultured fibroblast injection.

CONCLUSIONS

Autologous cultured fibroblast injection might be effective and safe to correct nasojugal grooves.

LEVEL OF EVIDENCE I

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Massive Traumatic Skin Defect Successfully Treated with Autologous, Bilayered, Tissue-Engineered MyDerm Skin Substitute: A Case Report

CASE

A 22-year-old man sustained a laceration that measured 180 cm, after debridement, over the anterolateral aspect of the right leg following a road traffic accident. The wound was treated with MyDerm (Universiti Kebangsaan Malaysia), a cell-based, bilayered, bioengineered dermal substitute that contains no animal-derived components and is fully autologous. For its construction, only a small area of skin was harvested from the left groin, which was closed primarily with absorbable sutures.

CONCLUSION

MyDerm is an alternative option for the treatment of a massive skin defect in patients who desire removal of only a negligible amount of skin from the donor site and when use of an autograft is insufficient.

Human serum alters cell culture behavior and improves spheroid formation in comparison to fetal bovine serum

BACKGROUND

The use of fetal bovine serum (FBS) as growth supplement for human cell and tissue culture is widely spread in basic research as well as in clinical approaches, although several limitations must be considered, such as unstable composition and availability, biosafety and ethical aspects. Regarding interspecies differences, xenogeneic growth factors may evoke incompatibilities and non-desired interactions with human cells resulting in imprecise outcome of human-relevant data.

METHODS

In this study the functionality of human serum (HS) has been investigated in comparison to FBS by assessing proliferation, migration and invasion of the human cervical cancer cell lines SiHa and HeLa. The effects of both sera on spheroid formation were analyzed microscopically.

RESULTS

Both, FBS and HS, stimulate cell proliferation and migration similarly, whereas HS significantly enhanced cell invasion. The spheroid formation assay revealed remarkable differences between both sera, especially for SiHa cells. While in FBS supplemented medium cells only formed loose aggregates, HS induced regularly shaped spheroids under all tested conditions.

CONCLUSION

We were able to demonstrate that HS and FBS differently influence behavior of cells in culture which may have an impact on experimental results, especially in 3D cultures.

Tissue-Engineered Skin Substitute Enhances Wound Healing after Radiation Therapy

OBJECTIVE

When given in conjunction with surgery for treating cancer, radiation therapy may result in impaired wound healing, which, in turn, could cause skin ulcers. In this study, bilayer and monolayer autologous skin substitutes were used to treat an irradiated wound.

MATERIALS AND METHODS

A single dose of 30 Gy of linear electron beam radiation was applied to the hind limb of nude mice before creating the skin lesion (area of 78.6 mm). Monolayer tissue-engineered skin substitutes (MTESSs) were prepared by entrapping cultured keratinocytes in fibrin matrix, and bilayer tissue-engineered skin substitutes (BTESSs) were prepared by entrapping keratinocytes and fibroblasts in separate layers. Bilayer tissue-engineered skin substitute and MTESS were implanted to the wound area. Gross appearance and wound area were analyzed to evaluate wound healing efficiency. Skin regeneration and morphological appearance were observed via histological and electron microscopy. Protein expressions of transforming growth factor β1 (TGF-β1), platelet-derived growth factor BB (PDGF-BB), and vascular endothelial growth factor (VEGF) in skin regeneration were evaluated by immunohistochemistry (IHC).

RESULTS

Macroscopic observation revealed that at day 13, treatments with BTESS completely healed the irradiated wound, whereas wound sizes of 1.1 ± 0.05 and 6.8 ± 0.14 mm were measured in the MTESS-treated and untreated control groups, respectively. Hematoxylin-eosin (H&E) analysis showed formation of compact and organized epidermal and dermal layers in the BTESS-treated group, as compared with MTESS-treated and untreated control groups. Ultrastructural analysis indicates maturation of skin in BTESS-treated wound evidenced by formation of intermediate filament bundles in the dermal layer and low intercellular space in the epidermal layer. Expressions of TGF-β1, PDGF-BB, and VEGF were also higher in BTESS-treated wounds, compared with MTESS-treated wounds.

CONCLUSIONS

These results indicate that BTESS is the preferred treatment for irradiated wound ulcers.

A 3D-psoriatic skin model for dermatological testing: The impact of culture conditions

Background

Inadequate representation of the human tissue environment during a preclinical screen can result in inaccurate predictions of compound effects. Consequently, pharmaceutical investigators are searching for preclinical models that closely resemble original tissue for predicting clinical outcomes.

Methods

The current research aims to compare the impact of using serum-free medium instead of complete culture medium during the last step of psoriatic skin substitute reconstruction. Skin substitutes were produced according to the self-assembly approach.

Results

Serum-free conditions have no negative impact on the reconstruction of healthy or psoriatic skin substitutes presented in this study regarding their macroscopic or histological appearances. ATR-FTIR results showed no significant differences in the CH₂ bands between psoriatic substitutes cultured with or without serum, thus suggesting that serum deprivation did not have a negative impact on the lipid organization of their stratum corneum. Serum deprivation could even lead to a better organization of healthy skin substitute lipids. Percutaneous analyses demonstrated that psoriatic substitutes cultured in serum-free conditions showed a higher permeability to hydrocortisone compared to controls, while no significant differences in benzoic acid and caffeine penetration profiles were observed.

Conclusions

Results obtained with this 3D-psoriatic skin substitute demonstrate the potential and versatility of the model. It could offer good prediction of drug related toxicities at preclinical stages performed in order to avoid unexpected and costly findings in the clinic.

General significance

Together, these findings offer a new approach for one of the most important challenges of the 21st century, namely, prediction of drug toxicity.

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Impact of serum-free conditions during psoriatic skin substitutes reconstruction.

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Lipids disorganization of healthy and psoriatic skin substitutes.

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Permeation profiles of healthy skin substitutes.

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Permeation profiles of psoriatic skin substitutes.

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Potential and veratility of a 3d-reconstructed model to perform dermatological testing.

Accelerated Development of Supramolecular Corneal Stromal-Like Assemblies from Corneal Fibroblasts in the Presence of Macromolecular Crowders

Tissue engineering by self-assembly uses the cells' secretome as a regeneration template and biological factory of trophic factors. Despite the several advantages that have been witnessed in preclinical and clinical settings, the major obstacle for wide acceptance of this technology remains the tardy extracellular matrix formation. In this study, we assessed the influence of macromolecular crowding (MMC)/excluding volume effect, a biophysical phenomenon that accelerates thermodynamic activities and biological processes by several orders of magnitude, in human corneal fibroblast (HCF) culture. Our data indicate that the addition of negatively charged galactose derivative (carrageenan) in HCF culture, even at 0.5% serum, increases by 12-fold tissue-specific matrix deposition, while maintaining physiological cell morphology and protein/gene expression. Gene analysis indicates that a glucose derivative (dextran sulfate) may drive corneal fibroblasts toward a myofibroblast lineage. Collectively, these results indicate that MMC may be suitable not only for clinical translation and commercialization of tissue engineering by self-assembly therapies, but also for the development of in vitro pathophysiology models.

Hepatectomised patient sera promote hepatocyte differentiation of human-induced pluripotent stem cells

BACKGROUND

Human induced pluripotent stem cells, which can be differentiated into hepatocyte-like cells, could provide a source for liver regeneration and bio-artificial liver devices. However, the functionality of hepatocyte-like cells is significantly lower than that of primary hepatocytes.

AIMS

To investigate whether serum from patients undergoing hepatectomy might promote differentiation from human induced pluripotent stem cells to hepatocyte-like cells.

METHODS

Serum from patients undergoing hepatectomy (acquired pre-hepatectomy and 3 hours, 1 day and 3 days post-hepatectomy) was used to replace foetal bovine serum when differentiating human induced pluripotent stem cells into hepatocyte-like cells. Properties of hepatocyte-like cells were assessed and compared with cells cultured in foetal bovine serum.

RESULTS

The differentiation efficiency and functionality of hepatocyte-like cells cultured in human serum 3 hours and 1 day post-hepatectomy were superior to those cultured in foetal bovine serum and human serum pre-hepatectomy. Human serum 3 days post-hepatectomy had an equal effect to that of human serum pre-hepatectomy. Some cytochrome P450 isozyme transcript levels of hepatocyte-like cells cultured in human serum were higher than those cultured in foetal bovine serum.

CONCLUSION

Human serum, particularly that acquired relatively soon after hepatectomy, can enhance the differentiation efficiency and functionality of hepatocyte-like cells derived from human induced pluripotent stem cells.

Alteration of skin properties with autologous dermal fibroblasts

Dermal fibroblasts are mesenchymal cells found between the skin epidermis and subcutaneous tissue. They are primarily responsible for synthesizing collagen and glycosaminoglycans; components of extracellular matrix supporting the structural integrity of the skin. Dermal fibroblasts play a pivotal role in cutaneous wound healing and skin repair. Preclinical studies suggest wider applications of dermal fibroblasts ranging from skin based indications to non-skin tissue regeneration in tendon repair. One clinical application for autologous dermal fibroblasts has been approved by the Food and Drug Administration (FDA) while others are in preclinical development or various stages of regulatory approval. In this context, we outline the role of fibroblasts in wound healing and discuss recent advances and the current development pipeline for cellular therapies using autologous dermal fibroblasts. The microanatomic and phenotypic differences of fibroblasts occupying particular locations within the skin are reviewed, emphasizing the therapeutic relevance of attributes exhibited by subpopulations of fibroblasts. Special focus is provided to fibroblast characteristics that define regional differences in skin, including the thick and hairless skin of the palms and soles as compared to hair-bearing skin. This regional specificity and functional identity of fibroblasts provides another platform for developing regional skin applications such as the induction of hair follicles in bald scalp or alteration of the phenotype of stump skin in amputees to better support their prosthetic devices.

The effects of human serum to the morphology, proliferation and gene expression level of the respiratory epithelium in vitro

The culture of human airway epithelial cells has played an important role in advancing our understanding of the metabolic and molecular mechanisms underlying normal function and disease pathology of airway epithelial cells. The present study focused on investigating the effects of human serum (HS) on the qualitative and quantitative properties of the human respiratory epithelium compared to the fetal bovine serum (FBS), as a supplement in culture. Respiratory epithelial (RE) cells derived from human nasal turbinate were co-cultured with fibroblasts, subsequently separated at 80-90% confluency by differential trypsinization. RE cells were then sub-cultured into 2 different plates containing 5% allogenic HS and FBS supplemented media respectively up to passage 1 (P1). Cell morphology, growth rate, cell viability and population doubling time were assessed under light microscope, and levels of gene expression were measured via real time reverse transcriptase-polymerase chain reaction (qRT-PCR). RE cells appeared as polygonal shape and expanded when cultured in HS whereas RE cells in FBS were observed to be easily matured thus limit the RE cells expansion. Proliferation rate of RE cells in HS supplemented media (7673.18 ± 1207.15) was 3 times higher compared to RE in FBS supplemented media (2357.68 ± 186.85). Furthermore, RE cells cultured in HS-supplemented media required fewer days (9.15 ± 1.10) to double in numbers compared to cells cultured in FBS-supplemented media (13.66 ± 0.81). Both the differences were significant (p<0.05). However, there were no significant differences in the viability of RE cells in both groups (p=0.105). qRT-PCR showed comparable expressions of gene Cytokeratin-14 (CK-14), Cytokeratin-18 (CK-18) and Mucin-5 subtype B (MUC5B) in RE cells cultured in both groups (p>0.05). In conclusion, HS is a comparatively better choice of media supplement in accelerating growth kinetics of RE cells in vitro thus producing a better quality of respiratory epithelium for future tracheal reconstruction.

Thyrotropin-releasing hormone (TRH) promotes wound re-epithelialisation in frog and human skin

There remains a critical need for new therapeutics that promote wound healing in patients suffering from chronic skin wounds. This is, in part, due to a shortage of simple, physiologically and clinically relevant test systems for investigating candidate agents. The skin of amphibians possesses a remarkable regenerative capacity, which remains insufficiently explored for clinical purposes. Combining comparative biology with a translational medicine approach, we report the development and application of a simple ex vivo frog (Xenopus tropicalis) skin organ culture system that permits exploration of the effects of amphibian skin-derived agents on re-epithelialisation in both frog and human skin. Using this amphibian model, we identify thyrotropin-releasing hormone (TRH) as a novel stimulant of epidermal regeneration. Moving to a complementary human ex vivo wounded skin assay, we demonstrate that the effects of TRH are conserved across the amphibian-mammalian divide: TRH stimulates wound closure and formation of neo-epidermis in organ-cultured human skin, accompanied by increased keratinocyte proliferation and wound healing-associated differentiation (cytokeratin 6 expression). Thus, TRH represents a novel, clinically relevant neuroendocrine wound repair promoter that deserves further exploration. These complementary frog and human skin ex vivo assays encourage a comparative biology approach in future wound healing research so as to facilitate the rapid identification and preclinical testing of novel, evolutionarily conserved, and clinically relevant wound healing promoters.

Suitability of autologous serum for expanding rabbit adipose-derived stem cell populations

Adipose-derived stem cells (ASCs) are believed to have potential use for treating many illnesses. Most cells, including ASCs, are generally cultured in medium containing fetal bovine serum (FBS). However, FBS, which could induce an immune response or infection, is not recommended for clinical applications. In the present study, we evaluated the morphology, proliferation rate, and characterization of rabbit ASCs grown in medium containing autologous serum (AS) and compared these cells to ones cultured with FBS. Morphological changes were monitored by microscopy and flow cytometry. Proliferation rates were assessed with cell counting and ASC phenotypes were characterized by flow cytometry using representative surface markers (CD44 and CD45). Expression of epidermal growth factor, brain-derived neurotrophic factor, and vascular endothelial growth factor was measured by reverse transcription-polymerase chain reaction. Results of our study showed that ASCs had a greater expansion rate in AS without developing morphological heterogeneity than cells grown in FBS. AS-cultured ASCs expressed representative growth factors, CD44 but not CD45, similar to cells cultured in FBS. Expression levels of some growth factors were different between AS and FBS. In conclusion, our findings indicated that AS could potentially be used as a culture medium supplement for the expansion of autologous ASCs.

Comparison of the effects between animal-derived trypsin and recombinant trypsin on human skin cells proliferation, gene and protein expression

Animal-derivative free reagents are preferred in skin cell culture for clinical applications. The aim of this study was to compare the performance and effects between animal-derived trypsin and recombinant trypsin for skin cells culture and expansion. Full thickness human skin was digested in 0.6 % collagenase for 6 h to liberate the fibroblasts, followed by treatment with either animal-derived trypsin; Trypsin EDTA (TE) or recombinant trypsin; TrypLE Select (TS) to liberate the keratinocytes. Both keratinocytes and fibroblasts were then culture-expanded until passage 2. Trypsinization for both cell types during culture-expansion was performed using either TE or TS. Total cells yield was determined using a haemocytometer. Expression of collagen type I, collagen type III (Col-III), cytokeratin 10, and cytokeratin 14 genes were quantified via RT-PCR and further confirmed with immunocytochemical staining. The results of our study showed that the total cell yield for both keratinocytes and fibroblasts treated with TE or TS were comparable. RT-PCR showed that expression of skin-specific genes except Col-III was higher in the TS treated group compared to that in the TE group. Expression of proteins specific to the two cell types were confirmed by immunocytochemical staining in both TE and TS groups. In conclusion, the performance of the recombinant trypsin is comparable with the well-established animal-derived trypsin for human skin cell culture expansion in terms of cell yield and expression of specific cellular markers.

Shelf-life evaluation of bilayered human skin equivalent, MyDerm™

Skin plays an important role in defense against infection and other harmful biological agents. Due to its fragile structure, skin can be easily damaged by heat, chemicals, traumatic injuries and diseases. An autologous bilayered human skin equivalent, MyDerm™, was engineered to provide a living skin substitute to treat critical skin loss. However, one of the disadvantages of living skin substitute is its short shelf-life, hence limiting its distribution worldwide. The aim of this study was to evaluate the shelf-life of MyDerm™ through assessment of cell morphology, cell viability, population doubling time and functional gene expression levels before transplantation. Skin samples were digested with 0.6% Collagenase Type I followed by epithelial cells dissociation with TrypLE Select. Dermal fibroblasts and keratinocytes were culture-expanded to obtain sufficient cells for MyDerm™ construction. MyDerm™ was constructed with plasma-fibrin as temporary biomaterial and evaluated at 0, 24, 48 and 72 hours after storage at 4°C for its shelf-life determination. The morphology of skin cells derived from MyDerm™ remained unchanged across storage times. Cells harvested from MyDerm™ after storage appeared in good viability (90.5%±2.7% to 94.9%±1.6%) and had short population doubling time (58.4±8.7 to 76.9±19 hours). The modest drop in cell viability and increased in population doubling time at longer storage duration did not demonstrate a significant difference. Gene expression for CK10, CK14 and COL III were also comparable between different storage times. In conclusion, MyDerm™ can be stored in basal medium at 4°C for at least 72 hours before transplantation without compromising its functionality.

Effects of epidermal growth factor on the proliferation and cell cycle regulation of cultured human amnion epithelial cells

Human amnion epithelial cells (HAECs) hold great promise in tissue engineering for regenerative medicine. Large numbers of HAECs are required for this purpose. Hence, exogenous growth factor is added to the culture medium to improve epithelial cells proliferation. The aim of the present study was to determine the effects of epidermal growth factor (EGF) on the proliferation and cell cycle regulation of cultured HAECs. HAECs at P1 were cultured for 7 days in medium containing an equal volume mix of HAM's F12: Dulbecco's Modified Eagles Medium (1:1) supplemented with different concentrations of EGF (0, 5, 10, 20, 30 and 50 ng/ml EGF) in reduced serum. Morphology, growth kinetics and cell cycle analysis using flow cytometry were assessed. Quantitative gene expression for cell cycle control genes, pluripotent transcription factors, epithelial genes and neuronal genes were also determined. EGF enhanced HAECs proliferation with optimal concentration at 10 ng/ml EGF. EGF significantly increased the proportion of HAECs at S- and G2/M-phase of the cell cycle compared to the control. At the end of culture, HAECs remained as diploid cells under cell cycle analysis. EGF significantly decreased the mRNA expression of p21, pRb, p53 and GADD45 in cultured HAECs. EGF also significantly decreased the pluripotent genes expression: Oct-3/4, Sox2 and Nanog; epithelial genes expression: CK14, p63, CK1 and Involucrin; and neuronal gene expression: NSE, NF-M and MAP 2. The results suggested that EGF is a strong mitogen that promotes the proliferation of HAECs through cell cycle regulation. EGF did not promote HAECs differentiation or pluripotent genes expression.

The high affinity IgE receptor (FcεRI) expression and function in airway smooth muscle

The airway smooth muscle (ASM) is no longer considered as merely a contractile apparatus and passive recipient of growth factors, neurotransmitters and inflammatory mediators signal but a critical player in the perpetuation and modulation of airway inflammation and remodeling. In recent years, a molecular link between ASM and IgE has been established through Fc epsilon receptors (FcεRs) in modulating the phenotype and function of these cells. Particularly, the expression of high affinity IgE receptor (FcεRI) has been noted in primary human ASM cells in vitro and in vivo within bronchial biopsies of allergic asthmatic subjects. The activation of FcεRI on ASM cells suggests a critical yet almost completely ignored network which may modulate ASM cell function in allergic asthma. This review is intended to provide a historical perspective of IgE effects on ASM and highlights the recent updates in the expression and function of FcεRI, and to present future perspectives of activation of this pathway in ASM cells.

Sequential use of human-derived medium supplements favours cardiovascular tissue engineering

For clinical application of tissue engineering strategies, the use of animal-derived serum in culture medium is not recommended, because it can evoke immune responses in patients. We previously observed that human platelet-lysate (PL) is favourable for cell expansion, but generates weaker tissue as compared to culture in foetal bovine serum (FBS). We investigated if human serum (HS) is a better human supplement to increase tissue strength. Cells were isolated from venous grafts of 10 patients and expanded in media supplemented with PL or HS, to determine proliferation rates and expression of genes related to collagen production and maturation. Zymography was used to assess protease expression. Collagen contraction assays were used as a two-dimensional (2D) model for matrix contraction. As a prove of principle, 3D tissue culture and tensile testing was performed for two patients, to determine tissue strength. Cell proliferation was lower in HS-supplemented medium than in PL medium. The HS cells produced less active matrix metallo-proteinase 2 (MMP2) and showed increased matrix contraction as indicated by gel contraction assays and 3D-tissue culture. Tensile testing showed increased strength for tissues cultured in HS when compared to PL. This effect was more pronounced if cells were sequentially cultured in PL, followed by tissue culture in HS. These data suggest that sequential use of PL and HS as substitutes for FBS in culture medium for cardiovascular tissue engineering results in improved cell proliferation and tissue mechanical properties, as compared to use of PL or HS apart.

[Influence of Aloe polysaccharide on proliferation and hyaluronic acid and hydroxyproline secretion of human fibroblasts in vitro]

OBJECTIVE

To investigate the effect of Aloe polysaccharide on proliferation and hyaluronic acid and hydroxyproline secretion of human fibroblasts in vitro.

METHODS

The fibroblasts were treated with different doses of polysaccharide (0, 25, 50, 100, 200, 400 mg/L). Subsequently, cell proliferation was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, cell cycle by flow cytometry, evaluation of the Aloe polysaccharide toxic effect by acridine orange-ethidium bromide staining, evaluation of the cell injury by lactate dehydrogenase (LDH) assay, and the collagen synthesis by (3)H-proline incorporation. In addition, hyaluronic acid and hydroxyproline levels in the supernatants of cultured fibroblasts were measured by enzyme-linked immunosorbent assay.

RESULTS

The proliferation of fibroblasts was induced with polysaccharide in a dose-dependent manner, reaching its highest level on 5th day. Meanwhile, the percentage of cells at phase G(0)/G(1) was decreased, while that at phases G(2)/M and S was increased significantly in Aloe polysaccharide-treated groups as compared with those in the control group (P<0.05). Additionally, the apoptosis of the fibroblasts showed no differences among all groups. The collagen synthesis was increased and cell injury decreased in polysaccharide-treated groups as compared with those in control group (P<0.05), while the levels of hyaluronic acid and hydroxyproline in the supernatants of fibroblasts treated with polysaccharide were significantly higher than those in the control group (P<0.05).

CONCLUSION

The Aloe polysaccharide promotes both the proliferation of fibroblasts and the production of hyaluronic acid and hydroxyproline in fibroblasts. This indicates that the Aloe polysaccharide may play an important role in the extracellular matrix remodeling during wound healing.

Autologous fibroblast culture in the repair of aging skin

BACKGROUND

Human cell cultures are being developed to replace various body tissues.

OBJECTIVE

To assess the safety and efficacy of dermal regeneration with the injection of young autologous fibroblasts obtained from culture containing serum from patients themselves.

MATERIALS AND METHODS

Dermal tissue from the groin of five patients was cultivated in M199 medium supplemented with 10% human serum. Four population doublings were obtained. The fibroblasts were injected intradermally into forehead wrinkles and periorbital and paranasal areas.

RESULT

At the fourth population doubling, a mean of 3.85 × 10(6) cells/mL was obtained; viability was 98%. Sixty days after completing treatment, with four injections given at 15-day intervals, periorbital tonicity had improved significantly, although the quantity of fibroblasts used resulted in little improvement to surface lines and no improvement at all in deeper wrinkles. After 6 months, no further changes were found beyond the initial results obtained.

CONCLUSION

Injection of skin fibroblasts cultivated in medium supplemented with human serum is a viable technique and provokes no side effects. Four injections given at 15-day intervals containing a total of 6.4 × 10(6) fibroblasts/mL resulted in significant improvement in periorbital skin flaccidity. Further studies should be conducted with larger sample sizes.

Clinical grade cultivation of human Schwann cell, by the using of human autologous serum instead of fetal bovine serum and without growth factors

Clinical grade cultivation of human schwann cell by the utilization of human autologous serum instead of fetal bovine serum, and also avoiding any growth factors, can increase safety level of this procedure in cases of clinical cell transplantation. The aim of this study was demonstration of the feasibility of clinical grade schwann cell cultivation. In this experimental study after obtaining consent from close relatives we harvested 10 sural nerves from brain death donors and then cultured in 10 seperated culture media plus autologous serum. We also prepared autologous serum from donor's whole blood. Then cultured cells were evaluated by S100 antibody staining for both morphology and purity. Cell purity range was from 97% to 99% (mean=98.11 ± 0.782%). Mean of the cell count was 14,055.56 ± 2,480.479 per micro liter. There was not significant correlation between cell purity and either the culture period or the age of donors (P>0.05). The spearman correlation coefficient for the cell purity with the period or the age of donors was 0.21 and 0.09, respectively. We demonstrated the feasibility of clinical grade schwann cell cultivation by the using of human autologous serum instead of fetal bovine serum and also without the using of growth factors. We also recommended all cell preparation facilities to adhere to the GMP and other similar quality disciplines especially in the preparation of clinically-used cell products.

Fetal bovine serum xenoproteins modulate human monocyte adhesion and protein release on biomaterials in vitro

Monocyte-derived macrophages are critical in the host-foreign body response to biomaterials and have been studied extensively in various culture conditions in vitro, such as medium supplemented with fetal bovine serum (FBS) or autologous human serum (AHS). Since monocyte maturation into macrophages is highly plastic and may vary considerably depending on the surface, isolation procedures and in vitro culture conditions, we hypothesize that variations in protein adsorption and serum type will greatly impact monocyte behavior in a surface-dependent manner. The impact of xenoproteins on monocyte-surface interactions has not been well studied methodically and the use of AHS rather than FBS for macrophage-biomaterials studies in vitro is far from universal. The commonly used reference materials - tissue culture polystyrene (TCPS), polyethylene glycol (PEG) and polydimethylsiloxane (PDMS) - were employed in this study and we found a 3-fold higher adherent monocyte density on TCPS when AHS was used vs. FBS-supplemented medium. On PEG hydrogels, an 8- to 10-fold higher adhesion density was observed when AHS was employed vs. FBS, while on PDMS no difference in adhesion density was observed between the two sera conditions. Additionally, the presence of lipopolysaccharide abrogated the serum-dependent effect on cell adhesion on TCPS. Significantly different variations in protein release were observed between the serum conditions on these surfaces; in particular, there was a 100-fold higher concentration of growth-related oncogene for the AHS condition on PDMS even though the adhesion levels were comparable between the two serum conditions. These results emphasize the combined impact of the surface type and FBS xenoproteins in mediating the observed monocyte response to biomaterials in vitro.