Estimating the time of infection for African swine fever in pig farms in Korea.

African swine fever (ASF) is a highly contagious and lethal disease with characteristics of hemorrhagic fever. ASF outbreaks in pig farms significantly damage the entire pork industry. Understanding the transmission dynamics of ASF is crucial to effectively respond. Notably, it is important to know when the infection started on the outbreak farm. This study aimed at establishing a procedure for estimating the time of infection on pig farms affected by the ASF outbreak in Korea. The protocol for sampling to detect ASF virus infection, the estimation of the time interval between infection and detection, and the estimation of the infection stage parameters for the simulation model were described. After infection, fattening sheds (9.8 days in median) had the longest detection time compared with pregnant (8.6 days) or farrowing sheds (8.0 days). The intervals were 8.8 days for farrow-to-finisher farms, 7.0 days for farrow-to-weaning farms, and 9.5 days for fattening farms. The findings of this study provide valuable insights into ASF outbreaks in pig farms thus, improving the disease control ability.

Umbilical cord-derived mesenchymal stem cell sheets transplanted subcutaneously enhance cell retention and survival more than dissociated stem cell injections.

BACKGROUND: Human umbilical cord-derived mesenchymal stem cell (hUC-MSC) sheets have recently attracted attention as an alternative approach to injected cell suspensions for stem cell therapy. However, cell engraftment and cytokine expression levels between hUC-MSC sheets and their cell suspensions in vivo have not yet been compared. This study compares hUC-MSC in vivo engraftment efficacy and cytokine expression for both hUC-MSC sheets and cell suspensions. METHODS: hUC-MSC sheets were prepared using temperature-responsive cell culture; two types of hUC-MSC suspensions were prepared, either by enzymatic treatment (trypsin) or by enzyme-free temperature reduction using temperature-responsive cell cultureware. hUC-MSC sheets and suspensions were transplanted subcutaneously into ICR mice through subcutaneous surgical placement and intravenous injection, respectively. hUC-MSC sheet engraftment after subcutaneous surgical transplantation was investigated by in vivo imaging while intravenously injected cell suspensions were analyzing using in vitro organ imaging. Cytokine levels in both transplant site tissues and blood were quantified by enzyme-linked immunosorbent assay. RESULTS: After subcutaneous transplant, hUC-MSC sheets exhibited longer engraftment duration than hUC-MSC suspensions. This was attributed to extracellular matrix (ECM) and cell-cell junctions retained in sheets but enzymatically altered in suspensions. hUC-MSC suspensions harvested using enzyme-free temperature reduction exhibited relatively long engraftment duration after intravenous injection compared to suspensions prepared using trypsin, as enzyme-free harvest preserved cellular ECM. High HGF and TGF-ß1 levels were observed in sheet-transplanted sites compared to hUC-MSC suspension sites. However, no differences in human cytokine levels in murine blood were detected, indicating that hUC-MSC sheets might exert local paracrine rather than endocrine effects. CONCLUSIONS: hUC-MSC sheet transplantation could be a more effective cell therapeutic approach due to enhanced engraftment and secretion of therapeutic cytokines over injected hUC-MSC suspensions.

Rapid and effective preparation of clonal bone marrow-derived mesenchymal stem/stromal cell sheets to reduce renal fibrosis.

Allogeneic "off-the-shelf" mesenchymal stem/stromal cell (MSC) therapy requires scalable, quality-controlled cell manufacturing and distribution systems to provide clinical-grade products using cryogenic cell banking. However, previous studies report impaired cell function associated with administering freeze-thawed MSCs as single cell suspensions, potentially compromising reliable therapeutic efficacy. Using long-term culture-adapted clinical-grade clonal human bone marrow MSCs (cBMSCs) in this study, we engineered cBMSC sheets in 24 h to provide rapid preparation. We then sought to determine the influence of cBMSC freeze-thawing on both in vitro production of pro-regenerative factors and in vivo ability to reduce renal fibrosis in a rat model compared to freshly harvested cBMSCs. Sheets from freeze-thawed cBMSCs sheets exhibited comparable in vitro protein production and gene expression of pro-regenerative factors [e.g., hepatocyte growth factor (HGF), vascular endothelial growth factor (VEGF), and interleukin 10 (IL-10)] to freshly harvested cBMSC sheets. Additionally, freeze-thawed cBMSC sheets successfully suppressed renal fibrosis in vivo in an established rat ischemia-reperfusion injury model. Despite previous studies reporting that freeze-thawed MSCs exhibit impaired cell functions compared to fresh MSC single cell suspensions, cell sheets engineered from freeze-thawed cBMSCs do not exhibit impaired cell functions, supporting critical steps toward future clinical translation of cBMSC-based kidney disease treatment.

Engineered Bone Marrow Stem Cell-Sheets Alleviate Renal Damage in a Rat Chronic Glomerulonephritis Model.

Although mesenchymal stem cell (MSC)-based regenerative therapy is being developed for the treatment of kidney diseases, cell delivery and engraftment still need to be improved. Cell sheet technology has been developed as a new cell delivery method, to recover cells as a sheet form retaining intrinsic cell adhesion proteins, which promotes its transplantation efficiency to the target tissue. We thus hypothesized that MSC sheets would therapeutically reduce kidney disease with high transplantation efficiency. When the chronic glomerulonephritis was induced by two injections of the anti-Thy 1.1 antibody (OX-7) in rats, the therapeutic efficacy of rat bone marrow stem cell (rBMSC) sheet transplantation was evaluated. The rBMSC-sheets were prepared using the temperature-responsive cell-culture surfaces and transplanted as patches onto the surface of two kidneys of each rat at 24 h after the first injection of OX-7. At 4 weeks, retention of the transplanted MSC-sheets was confirmed, and the animals with MSC-sheets showed significant reductions in proteinuria, glomerular staining for extracellular matrix protein, and renal production of TGFß1, PAI-1, collagen I, and fibronectin. The treatment also ameliorated podocyte and renal tubular injury, as evidenced by a reversal in the reductions of WT-1, podocin, and nephrin and by renal overexpression of KIM-1 and NGAL. Furthermore, the treatment enhanced gene expression of regenerative factors, and IL-10, Bcl-2, and HO-1 mRNA levels, but reduced TSP-1 levels, NF-kB, and NAPDH oxidase production in the kidney. These results strongly support our hypothesis that MSC-sheets facilitated MSC transplantation and function, and effectively retarded progressive renal fibrosis via paracrine actions on anti-cellular inflammation, oxidative stress, and apoptosis and promoted regeneration.

Fear of COVID-19 and social distancing on the health behavior of coronary heart disease patients.

PURPOSE: This study aimed to provide basic data to improve the health behavior of patients diagnosed with coronary artery disease during pandemics such as that caused by coronavirus disease 2019 (COVID-19) by identifying the fear of COVID-19 and the degree of social distancing behavior of coronary patients. METHODS: In this study, 162 patients diagnosed with coronary artery disease who received follow-up care at the cardiovascular center of Dong-A University Hospital in Busan were selected. The variables examined in this study included subjects' general characteristics and disease-related characteristics, fear of COVID 19, social distancing behavior, and health behavior. Data were collected from June 8-25, 2021, and data analysis was performed using the IBM SPSS26.0 program. RESULTS: The results showed that older participants, those who were religious, those with cohabitants, and those who showed better compliance with social distancing showed better health behavior practice. Factor with the greatest influence on the health behavior of patients with coronary artery disease was social distancing behavior (ß = 0.299, p < .001). CONCLUSION: After the COVID-19 pandemic, it is necessary to develop a health care program to promote the health behavior of high-risk patients, including coronary artery disease, in preparation for the COVID-19 era. The younger the patient, the fewer health activities are undertaken when living alone, so appropriate education and support for these individuals should increase the rate of implementation of health activities for coronary artery disease.

Mesenchymal Stem Cell Sheet Centrifuge-Assisted Layering Augments Pro-Regenerative Cytokine Production.

A focal advantage of cell sheet technology has been as a scaffold-free three-dimensional (3D) cell delivery platform capable of sustained cell engraftment, survival, and reparative function. Recent evidence demonstrates that the intrinsic cell sheet 3D tissue-like microenvironment stimulates mesenchymal stem cell (MSC) paracrine factor production. In this capacity, cell sheets not only function as 3D cell delivery platforms, but also prime MSC therapeutic paracrine capacity. This study introduces a "cell sheet multilayering by centrifugation" strategy to non-invasively augment MSC paracrine factor production. Cell sheets fabricated by temperature-mediated harvest were first centrifuged as single layers using optimized conditions of rotational speed and time. Centrifugation enhanced cell physical and biochemical interactions related to intercellular communication and matrix interactions within the single cell sheet, upregulating MSC gene expression of connexin 43, integrin ß1, and laminin α5. Single cell sheet centrifugation triggered MSC functional enhancement, secreting higher concentrations of pro-regenerative cytokines vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF), and interleukin-10 (IL-10). Subsequent cell sheet stacking, and centrifugation generated cohesive, bilayer MSC sheets within 2 h, which could not be accomplished within 24 h by conventional layering methods. Conventional layering led to H1F-1α upregulation and increased cell death, indicating a hypoxic thickness limitation to this approach. Comparing centrifuged single and bilayer cell sheets revealed that layering increased VEGF production 10-fold, attributed to intercellular interactions at the layered sheet interface. The "MSC sheet multilayering by centrifugation" strategy described herein generates a 3D MSC-delivery platform with boosted therapeutic factor production capacity.

Adverse drug events leading to emergency department visits: A multicenter observational study in Korea.

Adverse drug events are significant causes of emergency department visits. Systematic evaluation of adverse drug events leading to emergency department visits by age is lacking. This multicenter retrospective observational study evaluated the prevalence and features of adverse drug event-related emergency department visits across ages. We reviewed emergency department medical records obtained from three university hospitals between July 2014 and December 2014. The proportion of adverse drug events among total emergency department visits was calculated. The cause, severity, preventability, and causative drug(s) of each adverse drug event were analyzed and compared between age groups (children/adolescents [<18 years], adults [18-64 years], and the elderly [≥65 years]). Of 59,428 emergency department visits, 2,104 (3.5%) were adverse drug event-related. Adverse drug event-related emergency department visits were more likely to be female and older. Multivariate logistic regression analysis revealed that compared to non- adverse drug event-related cases, adverse drug event-related emergency department visitors were more likely to be female (60.6% vs. 53.6%, p<0.001, OR 1.285, 95% CI 1.025-1.603) and older (50.8 ± 24.6 years vs. 37.7 ± 24.4 years, p<0.001, OR 1.892, 95% CI: 1.397-2.297). Comorbidities such as diabetes, chronic kidney disease, chronic liver disease, and malignancies were also significantly associated with adverse drug event-related emergency department visits. Side effects were the most common type of adverse drug events across age groups, although main types differed substantially depending on age. Serious adverse drug events, hospitalizations, and adverse drug event-related deaths occurred more frequently in the elderly than in adults or children/adolescents. The proportion of adverse drug event-related emergency department visits that were preventable was 15.3%. Causative drugs of adverse drug events varied considerably depending on age group. Adverse drug event features differ substantially according to age group. The findings suggest that an age-specific approach should be adopted in the preventive strategies to reduce adverse drug events.

Big data-based risk assessment of poultry farms during the 2020/2021 highly pathogenic avian influenza epidemic in Korea.

Outbreaks of H5-type highly pathogenic avian influenza (HPAI) in poultry have been reported in various parts of the world. To respond to these continuous threats, numerous surveillance programs have been applied to poultry raising facilities as well as wild birds. In Korea, a surveillance program was developed aimed at providing a preemptive response to possible outbreaks at poultry farms. The purpose of this study is to comprehensively present the risks of HPAI evaluated by this program in relation to actual outbreak farms during the epidemic of 2020/2021. A deep learning-based risk assessment program was trained based on the pattern of livestock vehicles visiting poultry farms and HPAI outbreaks to calculate the risk of HPAI for farms linked by the movement of livestock vehicles (such farms are termed "epidemiologically linked farms"). A total of 7,984 risk assessments were conducted, and the results were categorized into four groups. The proportion of the highest risk level was greater in duck farms (13.6%) than in chicken farms (8.8%). Among the duck farms, the proportion of the highest risk level was much greater in farms where breeder ducks were raised (accounting for 26.4% of the risk) than in farms where ducks were raised to obtain meat (12.8% of the risk). A higher risk level was also found in cases where the species of the outbreak farm and epidemiologically linked farms were the same (proportion of the highest risk level = 13.2%) compared to that when the species between the two farms were different (7.9%). The overall proportion of farms with HPAI outbreaks among epidemiologically linked farms (attack rate, AR) was 1.7% as HPAI was confirmed on 67 of the 3,883 epidemiologically linked farms. The AR was highest for breeder ducks (15.3%) among duck farms and laying hens (4.8%) among chicken farms. The AR of the pairs where livestock vehicles entered the inner farm area was 1.3 times (95% confidence interval: 1.4-2.9) higher than that of all pairs. With the risk information provided, customized preventive measures can be implemented for each epidemiologically linked farm. The use of this risk assessment program would be a good example of information-based surveillance and support decision-making for controlling animal diseases.

Enhancing chondrogenic potential via mesenchymal stem cell sheet multilayering.

Advanced tissue engineering approaches for direct articular cartilage replacement in vivo employ mesenchymal stem cell (MSC) sources, exploiting innate chondrogenic potential to fabricate hyaline-like constructs in vitro within three-dimensional (3D) culture conditions. Cell sheet technology represents one such advanced 3D scaffold-free cell culture platform, and previous work has shown that 3D MSC sheets are capable of in vitro hyaline-like chondrogenic differentiation. The present study aims to build upon this understanding and elucidate the effects of an established cell sheet manipulation technique, cell sheet multilayering, on fabrication of MSC-derived hyaline-like cartilage 3D layered constructs in vitro. To achieve this goal, multilayered MSC sheets are prepared and assessed for structural and biochemical transitions throughout chondrogenesis. Results support MSC multilayering as a means of increasing construct thickness and 3D cellular interactions related to in vitro chondrogenesis, including N-cadherin, connexin 43, and integrin ß-1. Data indicate that increasing construct thickness from 14 µm (1-layer construct) to 25 µm (2-layer construct) increases these cellular interactions and subsequent in vitro MSC chondrogenesis. However, a clear initial thickness threshold (33 µm - 3-layer construct) is evident that decreases the rate and extent of in vitro chondrogenesis, specifically chondrogenic gene expressions (Sox9, aggrecan, type II collagen) and sulfated proteoglycan accumulation in deposited extracellular matrix (ECM). Together, these data support the utility of cell sheet multilayering as a platform for tailoring construct thickness and subsequent MSC chondrogenesis for future articular cartilage regeneration applications.

Safety and efficacy of human juvenile chondrocyte-derived cell sheets for osteochondral defect treatment.

Knee cartilage does not regenerate spontaneously after injury, and a gold standard regenerative treatment algorithm has not been established. This study demonstrates preclinical safety and efficacy of scaffold-free, human juvenile cartilage-derived-chondrocyte (JCC) sheets produced from routine surgical discards using thermo-responsive cultureware. JCCs exhibit stable and high growth potential in vitro over passage 10, supporting possibilities for scale-up to mass production for commercialization. JCC sheets contain highly viable, densely packed cells, show no anchorage-independent cell growth, express mesenchymal surface markers, and lack MHC II expression. In nude rat focal osteochondral defect models, stable neocartilage formation was observed at 4 weeks by JCC sheet transplantation without abnormal tissue growth over 24 weeks in contrast to the nontreatment group showing no spontaneous cartilage repair. Regenerated cartilage was safranin-O positive, contained type II collagen, aggrecan, and human vimentin, and lacked type I collagen, indicating that the hyaline-like neocartilage formed originates from transplanted JCC sheets rather than host-derived cells. This study demonstrates the safety of JCC sheets and stable hyaline cartilage formation with engineered JCC sheets utilizing a sustainable tissue supply. Cost-benefit and scaling issues for sheet fabrication and use support feasibility of this JCC sheet strategy in clinical cartilage repair.

Trends in Articular Cartilage Tissue Engineering: 3D Mesenchymal Stem Cell Sheets as Candidates for Engineered Hyaline-Like Cartilage.

Articular cartilage defects represent an inciting factor for future osteoarthritis (OA) and degenerative joint disease progression. Despite multiple clinically available therapies that succeed in providing short term pain reduction and restoration of limited mobility, current treatments do not reliably regenerate native hyaline cartilage or halt cartilage degeneration at these defect sites. Novel therapeutics aimed at addressing limitations of current clinical cartilage regeneration therapies increasingly focus on allogeneic cells, specifically mesenchymal stem cells (MSCs), as potent, banked, and available cell sources that express chondrogenic lineage commitment capabilities. Innovative tissue engineering approaches employing allogeneic MSCs aim to develop three-dimensional (3D), chondrogenically differentiated constructs for direct and immediate replacement of hyaline cartilage, improve local site tissue integration, and optimize treatment outcomes. Among emerging tissue engineering technologies, advancements in cell sheet tissue engineering offer promising capabilities for achieving both in vitro hyaline-like differentiation and effective transplantation, based on controlled 3D cellular interactions and retained cellular adhesion molecules. This review focuses on 3D MSC-based tissue engineering approaches for fabricating "ready-to-use" hyaline-like cartilage constructs for future rapid in vivo regenerative cartilage therapies. We highlight current approaches and future directions regarding development of MSC-derived cartilage therapies, emphasizing cell sheet tissue engineering, with specific focus on regulating 3D cellular interactions for controlled chondrogenic differentiation and post-differentiation transplantation capabilities.

3D cell sheet structure augments mesenchymal stem cell cytokine production.

Mesenchymal stem cells (MSCs) secrete paracrine factors that play crucial roles during tissue regeneration. An increasing body of evidence suggests that this paracrine function is enhanced by MSC cultivation in three-dimensional (3D) tissue-like microenvironments. Toward this end, this study explored scaffold-free cell sheet technology as a new 3D platform. MSCs cultivated on temperature-responsive culture dishes to a confluent 2D monolayer were harvested by temperature reduction from 37 to 20 °C that induces a surface wettability transition from hydrophobic to hydrophilic. Release of culture-adherent tension induced spontaneous cell sheet contraction, reducing the diameter 2.4-fold, and increasing the thickness 8.0-fold to render a 3D tissue-like construct with a 36% increase in tissue volume. This 2D-to-3D transition reorganized MSC actin cytoskeleton from aligned to multidirectional, corresponding to a cell morphological change from elongated in 2D monolayers to rounded in 3D cell sheets. 3D culture increased MSC gene expression of cell interaction proteins, ß-catenin, integrin ß1, and connexin 43, and of pro-tissue regenerative cytokines, vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF), and interleukin-10 (IL-10), and increased VEGF secretion per MSC 2.1-fold relative to 2D cultures. Together, these findings demonstrate that MSC therapeutic potency can be enhanced by 3D cell sheet tissue structure.

Cell cycle regulation in human hair follicle dermal papilla cells using nonthermal atmospheric pressure plasma-activated medium.

ABSTRACT: Nonthermal atmospheric pressure (NAP) plasmas have recently been developed and have been used for wound healing, blood coagulation, and cancer therapy. NAP plasmas can induce either cell proliferation or cell death, depending on the dose. Due to their efficacy and application easily, plasma activated mediums (PAMs) have been used in human cells recently.In atmosphere, NAP plasmas react with molecular content of air such as N2, O2, H2O vapor, etc, and generate a variety of reactive oxygen and nitrogen species. High reactive oxygen species (ROS) levels promote damage of cellular DNA, proteins, and lipids. Such damage can lead to cell-cycle arrest, and cellular death. However, low levels of ROS have been caused an increase in cell cycle progression.Human skin is arranged in 3 layers, including (from top to bottom) the epidermis (and its appendages), the dermis, and the hypodermis. Human dermal papilla cells (DPCs) are located in the middle or even deep part of the dermis. DPCs play a key role in hair regeneration, and a lot of effort have been made to promote DPC hair formation ability. DPC is increased proliferation, delayed senescence, and enhanced hair by depending on the amount of ROS through the NAP-PAM treatment.In this study, we used NAP plasmas to the human hair follicle DPCs exposed from 0 to 20 minutes, so we were investigated the effects of PAM on cell proliferation and cell cycle progression. After NAP-PAM treatment for 24 hours, cell cycle was arrested in the G0/G1 phase. The NAP-PAM-treated human hair follicle DPCs recovered gradually after 48 hours of the treatment compared to the untreated cells.Therefore, this approach offers promising results for further application of NAP-PAM in clinical dermatology. In future, it can be applied clinically in the form of active water that can delay the progression of baldness and alopecia areata.

Characterization of the Percival detector with soft X-rays.

In this paper the back-side-illuminated Percival 2-Megapixel (P2M) detector is presented, along with its characterization by means of optical and X-ray photons. For the first time, the response of the system to soft X-rays (250 eV to 1 keV) is presented. The main performance parameters of the first detector are measured, assessing the capabilities in terms of noise, dynamic range and single-photon discrimination capability. Present limitations and coming improvements are discussed.

Allogeneic mesenchymal stem cell sheet therapy: A new frontier in drug delivery systems.

The evolution of drug discovery exploded in the early 20th century with the advent of critical scientific advancements in organic chemistry, chemical analysis, and purification. Early drug generations focused largely on symptom control and pain management, effective targets for small-molecule drugs. Recently, the attention in drug discovery has shifted to pursuit of radical cures. Cell therapy presents the ideal attributes of a promising new drug, targeting specific tissues based on chemotactic cues and modulating secretion of instructive regenerative molecules in response to dynamic signaling from disease environments. To actuate the therapeutic potential of cell therapy toward worldwide clinical use, cell delivery methods that can effectively localize and engraft mesenchymal stem cells (MSCs) with high disease-site fidelity and enable dynamic MSC bioactive function are paramount. In this review, we discuss the evolution of cell therapies with a focus on stem cell advantages, as well as the limitations to these therapies. This review aims to introduce cell sheet technology as a breakthrough cell therapy with demonstrated therapeutic success across indications for heart, liver, and kidney tissue regeneration. Opportunities and anticipated clinical impacts of cell sheet technology using MSCs are discussed.

Cell Sheets Restore Secretory Function in Wounded Mouse Submandibular Glands.

Thermoresponsive cell culture plates release cells as confluent living sheets in response to small changes in temperature, with recovered cell sheets retaining functional extracellular matrix proteins and tight junctions, both of which indicate formation of intact and functional tissue. Our recent studies demonstrated that cell sheets are highly effective in promoting mouse submandibular gland (SMG) cell differentiation and recovering tissue integrity. However, these studies were performed only at early time points and extension of the observation period is needed to investigate duration of the cell sheets. Thus, the goal of this study was to demonstrate that treatment of wounded mouse SMG with cell sheets is capable of increasing salivary epithelial integrity over extended time periods. The results indicate that cell sheets promote tissue organization as early as eight days after transplantation and that these effects endure through Day 20. Furthermore, cell sheet transplantation in wounded SMG induces a significant time-dependent enhancement of cell polarization, differentiation and ion transporter expression. Finally, this treatment restored saliva quantity to pre-wounding levels at both eight and twenty days post-surgery and significantly improved saliva quality at twenty days post-surgery. These data indicate that cell sheets engineered with thermoresponsive cell culture plates are useful for salivary gland regeneration and provide evidence for the long-term stability of cell sheets, thereby offering a potential new therapeutic strategy for treating hyposalivation.

Fabrication of hyaline-like cartilage constructs using mesenchymal stem cell sheets.

Cell and tissue engineering approaches for articular cartilage regeneration increasingly focus on mesenchymal stem cells (MSCs) as allogeneic cell sources, based on availability and innate chondrogenic potential. Many MSCs exhibit chondrogenic potential as three-dimensional (3D) cultures (i.e. pellets and seeded biomaterial scaffolds) in vitro; however, these constructs present engraftment, biocompatibility, and cell functionality limitations in vivo. Cell sheet technology maintains cell functionality as scaffold-free constructs while enabling direct cell transplantation from in vitro culture to targeted sites in vivo. The present study aims to develop transplantable hyaline-like cartilage constructs by stimulating MSC chondrogenic differentiation as cell sheets. To achieve this goal, 3D MSC sheets are prepared, exploiting spontaneous post-detachment cell sheet contraction, and chondrogenically induced. Results support 3D MSC sheets' chondrogenic differentiation to hyaline cartilage in vitro via post-contraction cytoskeletal reorganization and structural transformations. These 3D cell sheets' initial thickness and cellular densities may also modulate MSC-derived chondrocyte hypertrophy in vitro. Furthermore, chondrogenically differentiated cell sheets adhere directly to cartilage surfaces via retention of adhesion molecules while maintaining the cell sheets' characteristics. Together, these data support the utility of cell sheet technology for fabricating scaffold-free, hyaline-like cartilage constructs from MSCs for future transplantable articular cartilage regeneration therapies.

Femoral Head Chondrocyte Viability at the Cam Deformity in Patients With Femoroacetabular Impingement Syndrome.

BACKGROUND: Patients with hip pathology, such as femoroacetabular impingement (FAI) or hip dysplasia, are known to sustain chondral delamination injuries identifiable during hip arthroscopy, with an incidence of 44% to 75%. There are studies focused on understanding acetabular chondral flap viability, but there is a dearth of research regarding the viability of femoral head cartilage overlying the cam deformity in FAI. PURPOSE: To describe the viability and immunohistochemistry staining patterns of femoral head cartilage in the setting of FAI. STUDY DESIGN: Descriptive laboratory study. METHODS: Between September 2018 and August 2019, a single surgeon prospectively collected full-thickness femoral cartilage from cam deformities in 14 patients with FAI undergoing osteoplasty. Samples were assessed for viability and underwent immunohistochemistry staining for collagen type I, collagen type II, and aggrecan. RESULTS: The data set included 14 patients. Twelve samples were assessed for viability and 14 for immunohistochemistry straining. The mean patient age was 34.1 years, and the mean body mass index was 24.69. Mean ± SD chondrocyte viability per patient was 52% ± 11%. At the time of cell isolation, 8 of the 12 patients had viability >50%, with a maximum of 68.2%. This viability increased after a primary culture period, varying from 9 to 13 days, with 10 of 12 samples having viability >90%. The viability mean after the culture period was 94.54% ± 4.89%. Harvested cartilage showed expressions of type I cartilage, type II collagen, and aggrecan in a pattern that is predictable for native cartilage. CONCLUSION: These data reveal that the cartilage in femoral head cartilage overlying cam deformity-much like that from acetabular chondral flaps-not only has baseline viability >50% (51.99% ± 10.83%) but the ability to increase in viability >90% after a culture period. There may be a role for use of femoral head cartilage as autograft to repair full-thickness cartilage defects of the acetabulum and femoral head, either at the time of osteochondroplasty or after a period of cell culture to improve cell viability. CLINICAL RELEVANCE: A dearth of information is available regarding the viability of femoral head cartilage. This study provides insight into the cartilage viability and response to culture.

Cell sheet tissue engineering for scaffold-free three-dimensional (3D) tissue reconstruction.

Three-dimensional (3D) reconstruction of highly functional tissues is of great importance in advancing the clinical benefit of tissue engineering and regenerative medicine. In the last quarter century, many studies have found that by engineering a 3D microenvironment that resembles the in vivo tissue condition, cells exhibit behaviors and functions that reflect those of native tissue. Biomaterial scaffolds are a central technology for providing 3D microenvironments in vitro, and, in conjunction with diverse design and cell seeding advents, have produced highly functional and complex 3D tissues. Here, we describe a new approach to creating 3D cell-dense tissue-like constructs without a biomaterial scaffold. Cell sheet technology with cell sheet layering strategies generates highly cell dense, engineered tissue capable of direct crosstalk with the tissue-engraftment surface, in addition to paracrine-mediated signaling. In this chapter, we will introduce methods of reconstructing 3D tissue using cell sheet technology and the advantages of a scaffold-free design.