Connective Tissue Research最新文献

{"title":"The BMP and FGF pathways reciprocally regulate odontoblast differentiation.","authors":"Karo Parsegian","doi":"10.1080/03008207.2022.2094789","DOIUrl":"10.1080/03008207.2022.2094789","url":null,"abstract":"<p><strong>Purpose: </strong>Previous studies demonstrated that the exposure of primary dental pulp (DP) cultures to fibroblast growth factor 2 (FGF2) between days 3-7 exerted significant and long-lasting stimulatory effects on odontoblast differentiation and <i>Dspp</i> expression. These effects involved the increased expression of components of bone morphogenetic protein (BMP) signaling and were reverted by a BMP inhibitor noggin. FGF2 also transiently stimulated osteoblast differentiation and the expression of <i>Ibsp</i> and <i>Dmp1</i>. The present study aimed to further explore interactions between BMP and FGF signaling during odontoblast and osteoblast differentiation in DP cultures.</p><p><strong>Materials and methods: </strong>Cultures were established using DP tissue isolated from non-transgenic and fluorescent reporter (DSPP-Cerulean, BSP-GFP, and DMP1-mCherry) transgenic mice and exposed to BMP2, FGF2, SU5402 (an FGF receptor inhibitor), and noggin between days 3-7. Mineralization, gene expression, fluorescent protein expression, and odontoblast formation were examined using xylenol orange, quantitative PCR, fluorometric analysis, and immunocytochemistry, respectively.</p><p><strong>Results: </strong>BMP2 activated SMAD1/5/8 but not ERK1/2 signaling, whereas FGF2 exerted opposite effects. BMP2 did not affect mineralization, the expression of <i>Ibsp</i> and <i>Dmp1</i>, and the percentage of DSPP-Cerulean+ odontoblasts but significantly increased <i>Dspp</i> and DSPP-Cerulean. In cultures exposed to BMP2 and FGF2, respectively, both SU5402 and noggin led to long-lasting decreases in <i>Dspp</i> and DSPP-Cerulean and transient decreases in <i>Dmp1</i> and DMP1-mCherry without affecting <i>Ibsp</i> and BSP-GFP.</p><p><strong>Conclusion: </strong>BMP2 and FGF2 exerted reciprocal stimulatory effects on odontoblast differentiation, whereas their effects on osteoblast differentiation were mediated independently. These data will further elucidate the perspectives of using BMP2 and FGF2 for dentin regeneration/repair.</p>","PeriodicalId":10661,"journal":{"name":"Connective Tissue Research","volume":"64 1","pages":"53-63"},"PeriodicalIF":2.9,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9832171/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9383642","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The adaptive response of the mandibular condyle to increased load is disrupted by ADAMTS5 deficiency.","authors":"Sarah C Porto, Alexandra Rogers-DeCotes, Emmaline Schafer, Christine B Kern","doi":"10.1080/03008207.2022.2102491","DOIUrl":"10.1080/03008207.2022.2102491","url":null,"abstract":"<p><strong>Objective: </strong>To determine the impact of increased load on the temporomandibular joint (TMJ) from mice deficient in the extracellular matrix protease ADAMTS5.</p><p><strong>Materials and methods: </strong>Wire springs exerting 0.5 N for 1 h/day for 5 days (Adamts5^+/+ -<i>n</i> = 18; Adamts5^-/- <i>n</i> = 19) or 0.8 N for 1 h/day for 10 days (Adamts5^+/+-<i>n</i> = 18; Adamts5^-/- <i>n</i> = 17) were used to increase murine TMJ load. Safranin O-staining was used to determine mandibular condylar cartilage (MCC) morphology. Chondrogenic factors Sox9 and aggrecan were immunolocalized. Microcomputed topography was employed to evaluate mineralized tissues, and Tartrate-Resistant Acid Phosphatase staining was used to quantify osteoclasts.</p><p><strong>Results: </strong>Increased load on the mandibular condyle of <i>Adamts5</i>^<i>-/-</i> mice resulted in an increase in the hypertrophic zone of mandibular condylar cartilage (MCC) compared to normal load (NL) (<i>P</i> < 0.01). In the trabecular bone of the mandibular condyle, the total volume (TV), bone volume (BV), trabecular thickness (TbTh), and trabecular separation (TbSp) of the mandibular condyles in <i>Adamts5</i>^<i>-/-</i> mice (<i>n</i> = 27) did not change significantly with increased load, compared to <i>Adamts5</i>^<i>+/+</i> (<i>n</i> = 38) that exhibited significant responses (TV-<i>P</i> < 0.05; BV-<i>P</i> < 0.001; TbTh-<i>P</i> < 0.01; TbSp-<i>P</i> < 0.01). The bone volume fraction (BV/TV) was significantly reduced in response to increased load in both <i>Adamts5</i>^<i>-/-</i> (<i>P</i> < 0.05) and <i>Adamts5</i>^<i>+/+</i> mandibular condyles (P < 0.001) compared to NL. Increased load in <i>Adamts5</i>^<i>-/-</i> mandibular condyles also resulted in a dramatic increase in osteoclasts compared to <i>Adamts5</i>^<i>-/-</i> NL (<i>P</i> < 0.001) and to <i>Adamts5</i>^<i>+/+</i> with increased load (<i>P</i> < 01).</p><p><strong>Conclusion: </strong>The trabeculated bone of the <i>Adamts5</i>^<i>-/-</i> mandibular condyle was significantly less responsive to the increased load compared to <i>Adamts5</i>^<i>+/+</i>. ADAMTS5 may be required for mechanotransduction in the trabeculated bone of the mandibular condyle.</p>","PeriodicalId":10661,"journal":{"name":"Connective Tissue Research","volume":"64 1","pages":"93-104"},"PeriodicalIF":2.9,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9852085/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9328623","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of non-steroidal anti-inflammatory drug (ibuprofen) in low and high dose on stemness and biological characteristics of human dental pulp-derived mesenchymal stem cells.","authors":"Hasan Salkın,&nbsp;Kemal Erdem Basaran","doi":"10.1080/03008207.2022.2083613","DOIUrl":"https://doi.org/10.1080/03008207.2022.2083613","url":null,"abstract":"<p><strong>Purpose: </strong>The effect of ibuprofen, an NSAID, on biological characteristics such as proliferation, viability, DNA damage and cell cycle in dental pulp derived stem cells (DPSCs) can be important for regenerative medicine. Our aim is to investigate how low and high doses of ibuprofen affect stem cell characteristics in DPSCs.</p><p><strong>Materials and methods: </strong>DPSCs were isolated from human teeth and characterized by flow cytometry and differentiation tests. Low dose (0.1 mmol/L) and high dose (3 mmol/L) ibuprofen were administered to DPSCs. Surface markers between groups were analyzed by immunofluorescence staining. Membrane depolarization, DNA damage, viability and cell cycle analysis were performed between groups using biological activity test kits. Cellular proliferation was measured by the MTT and cell count kit. Statistical analyzes were performed using GraphPad Prism software.</p><p><strong>Results: </strong>High dose ibuprofen significantly increased CD44 and CD73 expression in DPSCs. High-dose ibuprofen significantly reduced mitochondrial membrane depolarization in DPSCs. It was determined that DNA damage in DPSCs decreased significantly with high dose ibuprofen. Parallel to this, cell viability increased significantly in the ibuprofen applied groups. High-dose ibuprofen was found to increase mitotic activity in DPSCs. Proliferation in DPSCs increased in parallel with the increase in mitosis stage because of high-dose ibuprofen administration compared to the control and low-dose ibuprofen groups. Our proliferation findings appeared to support cell cycle analyses.</p><p><strong>Conclusion: </strong>High dose ibuprofen improved the immunophenotypes and biological activities of DPSCs. The combination of ibuprofen in the use of DPSCs in regenerative medicine can make stem cell therapy more effective.</p>","PeriodicalId":10661,"journal":{"name":"Connective Tissue Research","volume":"64 1","pages":"14-25"},"PeriodicalIF":2.9,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9683125","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of aging on tendon homeostasis, tendinopathy development, and impaired healing.","authors":"Antonion Korcari, Samantha J Przybelski, Anne Gingery, Alayna E Loiselle","doi":"10.1080/03008207.2022.2102004","DOIUrl":"10.1080/03008207.2022.2102004","url":null,"abstract":"<p><p>Aging is a complex and progressive process where the tissues of the body demonstrate a decreased ability to maintain homeostasis. During aging, there are substantial cellular and molecular changes, with a subsequent increase in susceptibility to pathological degeneration of normal tissue function. In tendon, aging results in well characterized alterations in extracellular matrix (ECM) structure and composition. In addition, the cellular environment of aged tendons is altered, including a marked decrease in cell density and metabolic activity, as well as an increase in cellular senescence. Collectively, these degenerative changes make aging a key risk factor for the development of tendinopathies and can increase the frequency of tendon injuries. However, inconsistencies in the extent of age-related degenerative impairments in tendons have been reported, likely due to differences in how \"old\" and \"young\" age-groups have been defined, differences between anatomically distinct tendons, and differences between animal models that have been utilized to study the impact of aging on tendon homeostasis. In this review, we address these issues by summarizing data by well-defined age categories (young adults, middle-aged, and aged) and from anatomically distinct tendon types. We then summarize in detail how aging affects tendon mechanics, structure, composition, and the cellular environment based on current data and underscore what is currently not known. Finally, we discuss gaps in the current understanding of tendon aging and propose key avenues for future research that can shed light on the specific mechanisms of tendon pathogenesis due to aging.</p>","PeriodicalId":10661,"journal":{"name":"Connective Tissue Research","volume":"64 1","pages":"1-13"},"PeriodicalIF":2.9,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9851966/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9683143","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Post-injury tendon mechanics are not affected by tamoxifen treatment.","authors":"Zakary M Beach, Ashley K Fung, Stephanie N Weiss, Louis J Soslowsky","doi":"10.1080/03008207.2022.2097907","DOIUrl":"10.1080/03008207.2022.2097907","url":null,"abstract":"<p><strong>Purpose: </strong>A growing interest in the mechanisms that govern tendon healing has resulted in the develop-ment of tools, such as the tamoxifen-inducible mouse knockdown model, to address these questions. However, tamoxifen is a selective estrogen receptor modulator and may interfere with the tendon healing process. The objective of this study was to evaluate the effects of tamoxifen on post-injury tendon mechanics in wild-type mice.</p><p><strong>Methods: </strong>The mice underwent treatment at the time of injury using an established mouse injury model and the injured tendons were evaluated 3 weeks post-injury. The treatment contained tamoxifen suspended in corn oil and was compared to a treatment with only corn oil, as well as mice with no treatment. Tendons were evaluated by measuring the quasi-static and viscoelastic mechanics, collagen fiber realignment, cellularity, and nuclear morphology.</p><p><strong>Results: </strong>Mechanical testing of the tendons post-injury revealed no changes to viscoelastic mechanics, quasi-static mechanics, or collagen realignment during loading after tamoxifen treatment with the dosage regimen utilized (three daily injections of 4.5 mg/40 g body weight). Additionally, histological analysis revealed no changes to cellularity or cell nuclear shape.</p><p><strong>Conclusion: </strong>Overall, this study revealed that tamoxifen treatment at the time of tendon injury did not result in changes to tendon mechanics or the histological parameters at 3 weeks post-injury.</p>","PeriodicalId":10661,"journal":{"name":"Connective Tissue Research","volume":"64 1","pages":"75-81"},"PeriodicalIF":2.9,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9832173/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9383640","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Proanthocyanidins inhibit the apoptosis and aging of nucleus pulposus cells through the PI3K/Akt pathway delaying intervertebral disc degeneration.","authors":"Hai-Wei Chen,&nbsp;Ming-Qiang Liu,&nbsp;Guang-Zhi Zhang,&nbsp;Cang-Yu Zhang,&nbsp;Zhao-Heng Wang,&nbsp;Ai-Xin Lin,&nbsp;Ji-He Kang,&nbsp;Wen-Zhao Liu,&nbsp;Xu-Dong Guo,&nbsp;Yi-Dian Wang,&nbsp;Xue-Wen Kang","doi":"10.1080/03008207.2022.2063121","DOIUrl":"https://doi.org/10.1080/03008207.2022.2063121","url":null,"abstract":"<p><strong>Background: </strong>Low back pain is a common symptom of intervertebral disc degeneration (IDD), which seriously affects the quality of life of patients. The abnormal apoptosis and senescence of nucleus pulposus (NP) cells play important roles in the pathogenesis of IDD. Proanthocyanidins (PACs) are polyphenolic compounds with anti-apoptosis and anti-aging effects. However, their functions in NP cells are not yet clear. Therefore, this study was performed to explore the effects of PACs on NP cell apoptosis and aging and the underlying mechanisms of action.</p><p><strong>Methods: </strong>Cell viability was evaluated by cell counting kit-8 (CCK-8) assay. The apoptosis rate was determined TUNEL assays. Levels of apoptosis-associated molecules (Bcl-2, Bax, C-caspase-3 and Caspase-9) were evaluated via western blot. The senescence was observed through SA-β-gal staining and western blotting analysis was performed to observe the expression of senescence-related molecules (p-P53, P53, P21 and P16).</p><p><strong>Results: </strong>Pretreatment with PACs exhibited protective effects against IL-1β-induced NP cell apoptosis including apoptosis rate, expressions of proapoptosis and antiapoptosis related genes and protein. PACs could also alleviate the increase of p-p53, P21, and P16 in IL-1β-treated NP cells. SA-β-gal staining showed that IL-1β-induced senescence of NP cells was prevented by PACs pertreatment. In addition, PACs activated PI3K/Akt pathway in IL-1β-stimulated NP cells. However, these protected effects were inhibited after LY294002 treatment.</p><p><strong>Conclusion: </strong>The results of the present study showed that PACs inhibit IL-1β-induced apoptosis and aging of NP cells by activating the PI3K/Akt pathway, and suggested that PACs have therapeutic potential for IDD.</p>","PeriodicalId":10661,"journal":{"name":"Connective Tissue Research","volume":"63 6","pages":"650-662"},"PeriodicalIF":2.9,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10219820","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Clinical and laboratory findings following transplantation of allogeneic adipose-derived mesenchymal stromal cells in knee osteoarthritis, a brief report.","authors":"Bahareh Sadri,&nbsp;Atena Tamimi,&nbsp;Shirin Nouraein,&nbsp;Abolfazl Bagheri Fard,&nbsp;Javad Mohammadi,&nbsp;Mehdi Mohammadpour,&nbsp;Mohammad Hassanzadeh,&nbsp;Amir Bajouri,&nbsp;Hoda Madani,&nbsp;Maryam Barekat,&nbsp;Shahedeh Karimi Torshizi,&nbsp;Mahrooz Malek,&nbsp;Maede Ghorbani Liastani,&nbsp;Alireza Beheshti Maal,&nbsp;Maryam Niknejadi,&nbsp;Massoud Vosough","doi":"10.1080/03008207.2022.2074841","DOIUrl":"https://doi.org/10.1080/03008207.2022.2074841","url":null,"abstract":"<p><strong>Background: </strong>Mesenchymal stromal cells (MSCs) injection has been proposed as an innovative treatment for knee osteoarthritis (KOA). Since, allogeneic MSCs can be available as off-the-shelf products, they are preferable in regenerative medicine. Among different sources for MSCs, adipose-derived MSCs (AD-MSCs) appear to be more available.</p><p><strong>Methods: </strong>Three patients with KOA were enrolled in this study. A total number of 100 × 10⁶ AD-MSCs was injected intra-articularly, per affected knee. They were followed up for 6 months by the assessment of clinical outcomes, magnetic resonance imaging (MRI), and serum inflammatory biomarkers.</p><p><strong>Results: </strong>The primary outcome of this study was safety and feasibility of allogeneic AD-MSCs injection during the 6 months follow-up. Fortunately, no serious adverse events (SAEs) were reported. Assessment of secondary outcomes of visual analogue scale (VAS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and knee osteoarthritis outcome score (KOOS) indicated improvement in all patients. Comparison between baseline and endpoint findings of MRI demonstrated a slight improvement in two patients. In addition, decrease in serum cartilage oligomeric matrix protein (COMP) and hyaluronic acid (HA) indicated the possibility of reduced cartilage degeneration. Moreover, quantification of serum interleukin-10 (IL-10) and interleukin-6 (IL-6) levels indicated that the host immune system immunomodulated after infusion of AD-MSCs.</p><p><strong>Conclusion: </strong>Intra-articular injection of AD-MSCs is safe and could be effective in cartilage regeneration in KOA. Preliminary assessment after six-month follow-up suggests the potential efficacy of this intervention which would need to be confirmed in randomized controlled trials on a larger population.</p><p><strong>Trial registration: </strong>This study was registered in the Iranian registry of clinical trials (https://en.irct.ir/trial/46) in 24 April 2018 with identifier IRCT20080728001031N23.</p>","PeriodicalId":10661,"journal":{"name":"Connective Tissue Research","volume":"63 6","pages":"663-674"},"PeriodicalIF":2.9,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10469267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cyclic mechanical stretch regulates the AMPK/Egr1 pathway in tenocytes via Ca2+-mediated mechanosensing.","authors":"Yu-Ting Huang,&nbsp;Yu-Fu Wu,&nbsp;Hsing-Kuo Wang,&nbsp;Chung-Chen Jane Yao,&nbsp;Yi-Heng Chiu,&nbsp;Jui-Sheng Sun,&nbsp;Yuan-Hung Chao","doi":"10.1080/03008207.2022.2044321","DOIUrl":"https://doi.org/10.1080/03008207.2022.2044321","url":null,"abstract":"<p><strong>Purpose: </strong>Mechanical stimuli are essential for the maintenance of tendon tissue homeostasis. The study aims to elucidate the mechanobiological mechanisms underlying the maintenance of tenocyte homeostasis by cyclic mechanical stretch under high-glucose (HG) condition.</p><p><strong>Materials and methods: </strong>Primary tenocytes were isolated from rat Achilles tendon and 2D-cultured under HG condition. The <i>in vitro</i> effects of a single bout, 2-h cyclic biaxial stretch session (1 Hz, 8%) on primary rat tenocytes were explored through Flexcell system. Cell viability, tenogenic gene expression, intracellular calcium concentration, focal adhesion kinase (FAK) expression, and signaling pathway activation were analyzed in tenocytes with or without mechanical stretch.</p><p><strong>Results: </strong>Mechanical stretch increased tenocyte proliferation and upregulated early growth response protein 1 (Egr1) expression. An increase in intracellular calcium was observed after 30 min of stretching. Mechanical stretch phosphorylated FAK, calmodulin-dependent protein kinase kinase 2 (CaMKK2), and 5' adenosine monophosphate-activated protein kinase (AMPK) in a time-dependent manner, and these effects were abrogated after blocking intracellular calcium. Inhibition of FAK, CaMKK2, and AMPK downregulated the expression of Egr1. In addition, mechanical stretch reinforced cytoskeletal organization via calcium (Ca2+)/FAK signaling.</p><p><strong>Conclusions: </strong>Our study demonstrated that mechanical stretch-induced calcium influx activated CaMKK2/AMPK signaling and FAK-cytoskeleton reorganization, thereby promoting the expression of Egr1, which may help maintain tendon cell characteristics and homeostasis in the context of diabetic tendinopathy.</p>","PeriodicalId":10661,"journal":{"name":"Connective Tissue Research","volume":"63 6","pages":"590-602"},"PeriodicalIF":2.9,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10757517","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of cells on spatial quantification of proteoglycans in articular cartilage of small animals.","authors":"Kalle Karjalainen, Petri Tanska, Scott C Sibole, Santtu Mikkonen, Walter Herzog, Rami K Korhonen, Eng Kuan Moo","doi":"10.1080/03008207.2022.2048827","DOIUrl":"10.1080/03008207.2022.2048827","url":null,"abstract":"<p><strong>Objective: </strong>Histochemical characterization of proteoglycan content in articular cartilage is important for the understanding of osteoarthritis pathogenesis. However, cartilage cells may interfere with the measurement of matrix proteoglycan content in small animal models (e.g. mice and rats) due to the high cell volume fraction (38%) in mice compared to human tissue (~1%). We investigated whether excluding the cells from image analysis affects the histochemically measured proteoglycan content of rat knee joint cartilage and assessed the effectiveness of a deep learning algorithm-based tool named U-Net in cell segmentation.</p><p><strong>Design: </strong>Histological sections were stained with Safranin-O, after which optical densities were measured using digital densitometry to estimate proteoglycan content. U-Net was trained with 600 annotated Safranin-O cartilage images for exclusion of cells from the cartilage extracellular matrix. Optical densities of the ECM with and without cells were compared as a function of normalized tissue depth.</p><p><strong>Results: </strong>U-Net cell segmentation was accurate, with the measured cell area fraction following largely that of ground-truth images (average difference: 4.3%). Cell area fraction varied as a function of tissue depth and took up 8-21% of the tissue area. The exclusion of cells from the analysis led to an increase in the analyzed depth-dependent optical density of cartilage by approximately 0.6-1.8% (<i>p</i> < 0.01).</p><p><strong>Conclusions: </strong>Although the effect of cells on the analyzed proteoglycan content is small, it should be considered for improved sensitivity, especially at the onset of the disease during which cells may proliferate in small animals.</p>","PeriodicalId":10661,"journal":{"name":"Connective Tissue Research","volume":"63 6","pages":"603-614"},"PeriodicalIF":2.9,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10774449","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Oral mucosa equivalents, prevascularization approaches, and potential applications.","authors":"Daniela S Masson-Meyers, Luiz E Bertassoni, Lobat Tayebi","doi":"10.1080/03008207.2022.2035375","DOIUrl":"10.1080/03008207.2022.2035375","url":null,"abstract":"<p><strong>Background: </strong>Oral mucosa equivalents (OMEs) have been used as <i>in vitro</i> models (eg, for studies of human oral mucosa biology and pathology, toxicological and pharmacological tests of oral care products), and clinically to treat oral defects. However, the human oral mucosa is a highly vascularized tissue and implantation of large OMEs can fail due to a lack of vascularization. To develop equivalents that better resemble the human oral mucosa and increase the success of implantation to repair large-sized defects, efforts have been made to prevascularize these constructs.</p><p><strong>Purpose: </strong>The aim of this narrative review is to provide an overview of the human oral mucosa structure, common approaches for its reconstruction, and the development of OMEs, their prevascularization, and <i>in vitro</i> and clinical potential applications.</p><p><strong>Study selection: </strong>Articles on non-prevascularized and prevascularized OMEs were included, since the development and applications of non-prevascularized OMEs are a foundation for the design, fabrication, and optimization of prevascularized OMEs.</p><p><strong>Conclusions: </strong>Several studies have reported the development and <i>in vitro</i> and clinical applications of OMEs and only a few were found on prevascularized OMEs using different approaches of fabrication and incorporation of endothelial cells, indicating a lack of standardized protocols to obtain these equivalents. However, these studies have shown the feasibility of prevascularizing OMEs and their implantation in animal models resulted in enhanced integration and healing. Vascularization in tissue equivalents is still a challenge, and optimization of cell culture conditions, biomaterials, and fabrication techniques along with clinical studies is required.</p>","PeriodicalId":10661,"journal":{"name":"Connective Tissue Research","volume":"63 5","pages":"514-529"},"PeriodicalIF":2.9,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9357199/pdf/nihms-1823920.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10131613","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}