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The clinical translation of bone tissue engineering for reconstructing large bone defects has not advanced without hurdles. The in vivo bioreactor (IVB) concept may therefore bridge between bone tissue engineering and reconstructive surgery by employing the patient body for prefabricating new prevascularized tissues. Ideally, IVB should minimize the need for exogenous growth factors/cells. Periosteal tissues are promising for IVB approaches to prefabricate tissue-engineered bone (TEB) flaps. However, the significance of preserving the periosteal vascular supply has not been adequately investigated. This study assessed muscle IVB with and without periosteal/pericranial grafts and flaps for prefabricating TEB flaps to reconstruct mandibular defects in sheep. The sheep (n = 14) were allocated into 4 groups: muscle IVB (M group; n M = 3), muscle + periosteal graft (MP group; n MP = 4), muscle + periosteal flap (MVP group; n MVP = 4), and control group (n Control = 3). In the first surgery, alloplastic bone blocks were implanted in the brachiocephalic muscle (M) with a periosteal graft (MP) or with a vascularized periosteal flap (MVP). After 9 wk, the prefabricated TEB flaps were transplanted to reconstruct a mandibular angle defect. In the control group, the defects were reconstructed by non-prevascularized bone blocks. Computed tomography (CT) scans were performed after 13 wk and after 23 wk at termination, followed by micro-CT (µCT) and histological analyses. Both CT and µCT analysis revealed enhanced new bone formation and decreased residual biomaterial volume in the MVP group compared with control and MP groups, while the M group showed less new bone formation and more residual biomaterial. The histological analysis showed that most of the newly formed bone emerged from defect edges, but larger areas of new bone islands were found in MP and MVP groups. The MVP group showed enhanced vascularization and higher biomaterial remodeling rates. The periosteal flaps boosted the reconstructive potential of the prefabricated TEB flaps. The regenerative potential of the periosteum was manifested after the transplantation into the mechanically stimulated bony defect microenvironment. [ABSTRACT FROM AUTHOR]

A major challenge with extensive craniomaxillofacial bone reconstruction is the limited donor-site availability to reconstruct defects predictably and accurately according to the anatomical shape of the patient. Here, patient-specific composite bioimplants, consisting of cross-linked poly(trimethylene carbonate) (PTMC) networks and β-tricalcium phosphate (β-TCP), are tested in vivo in twelve Göttingen minipigs in a large mandibular continuity defect model. The 25 mm defects are supported by patient-specific titanium reconstruction plates and receive either osteoconductive composite bioimplants (PTMC+TCP), neat polymer network bioimplants (PTMC), autologous bone segments (positive control), or are left empty (negative control). Postoperatively, defects treated with bioimplants show evident ossification at 24 weeks. Histopathologic evaluation reveals that neat PTMC bioimplant surfaces are largely covered with fibrous tissue, while in the PTMC+TCP bioimplants, bone attached directly to the implant surface shows good osteoconduction and histological signs of osteoinductivity. However, PTMC+TCP bioimplants are associated with high incidence of necrosis and infection, possibly due to rapid resorption and/or particle size of the used β-TCP. The study highlights the importance of testing bone regeneration implants in a clinically relevant large animal model and at the in situ reconstruction site, since results on small animal models and studies in nonloadbearing areas do not translate directly., (© 2022 The Authors. Macromolecular Bioscience published by Wiley-VCH GmbH.)

It was hypothesized that premedication with vatinoxan, a peripheral α 2 -adrenoceptor antagonist, would mitigate xylazine-induced pulmonary alterations in sheep. Fourteen adult sheep were allotted into two equal groups and premedicated with either vatinoxan (750 µg/kg IV) or saline and sedated 10 min later with xylazine (500 µg/kg IV). Arterial oxygen saturation (SpO 2 ) was measured and respiratory rate (RR) counted at intervals. The sheep were euthanized with IV pentobarbital 10 min after xylazine administration. The severity of pulmonary parenchymal alterations was assessed and graded grossly and histologically and correlations of the morphological changes with SpO 2 evaluated. Following xylazine injection, SpO 2 was significantly higher and RR significantly lower with vatinoxan than with saline and the sheep administered vatinoxan exhibited significantly smaller quantities of tracheal foam than those receiving saline. No significant differences in macroscopic oedema scores were detected between treatments. In contrast, the vatinoxan-treated animals exhibited significantly graver microscopic interstitial alveolar oedema and haemorrhage than saline-treated animals. The histological severity scores did not correlate with changes in SpO 2 . In conclusion, xylazine induced a marked reduction in SpO 2 which was abolished by the prior administration of vatinoxan. The histologically detected alterations after pentobarbital euthanasia with vatinoxan premedication need to be studied further., (© 2021 The Authors. Journal of Veterinary Pharmacology and Therapeutics published by John Wiley & Sons Ltd.)

Objectives: To investigate the extent of vatinoxan distribution into sheep brain, and whether vatinoxan influences brain concentrations of xylazine; and to examine the utility of cerebrospinal fluid (CSF) as a surrogate of brain tissue concentrations for vatinoxan and xylazine., Study Design: Randomised, blinded, experimental study., Animals: A total of 14 adult female sheep., Methods: Sheep were randomly allocated into two equal groups and premedicated with either intravenous (IV) vatinoxan (750 μg kg -1 , VX) or saline (SX) administered 10 minutes before IV xylazine (500 μg kg -1 ). Sedation was subjectively assessed at selected intervals before and after treatments. At 10 minutes after xylazine administration, a venous blood sample was collected and the sheep were immediately euthanised with IV pentobarbital (100 mg kg -1 ). Plasma, CSF and brain tissues were harvested, and concentrations of vatinoxan and xylazine were quantified using liquid chromatography-tandem mass spectrometry. Drug ratios were then calculated and the data were analysed as appropriate., Results: The brain-to-plasma and CSF-to-plasma ratios of vatinoxan were 0.06 ± 0.013 and 0.05 ± 0.01 (mean ± standard deviation), respectively. Xylazine brain concentrations were not significantly different (835 ± 262 versus 1029 ± 297 ng g -1 in groups VX and SX, respectively) and were approximately 15-fold higher than those in plasma. The CSF-to-brain ratio of vatinoxan was 0.8 ± 0.2, whereas xylazine concentrations in the brain were approximately 17-fold greater than those in CSF, with and without vatinoxan., Conclusions and Clinical Relevance: Vatinoxan did not significantly affect sedation with xylazine or the concentrations of xylazine in the brain. CSF is not a good predictor of xylazine concentrations in the brain, whereas vatinoxan concentrations were concordant between the brain and CSF, using the dosages in this study., (Copyright © 2021 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Osteosarcoma (OS) is an aggressive bone tumor that mainly affects children and adolescents. OS has a strong tendency to relapse and metastasize, resulting in poor prognosis and survival. The high heterogeneity and genetic complexity of OS make it challenging to identify new therapeutic targets. Mesenchymal stem cells (MSCs) are multipotent stem cells that can differentiate into adipocytes, osteoblasts, or chondroblasts. OS is thought to originate at some stage in the differentiation process of MSC to pre-osteoblast or from osteoblast precursors. MSCs contribute to OS progression by interacting with tumor cells via paracrine signaling and affect tumor cell proliferation, invasion, angiogenesis, immune response, and metastasis. Extracellular vesicles (EVs), secreted by OS cells and MSCs in the tumor microenvironment, are crucial mediators of intercellular communication, driving OS progression by transferring miRNAs/RNA and proteins to other cells. MSC-derived EVs have both pro-tumor and anti-tumor effects on OS progression. MSC-EVs can be also engineered to deliver anti-tumor cargo to the tumor site, which offers potential applications in MSC-EV-based OS treatment. In this review, we highlight the role of MSCs in OS, with a focus on EV-mediated communication between OS cells and MSCs and their role in OS pathogenesis and therapy.

Mesenchymal stem cells (MSCs) are commonly isolated from bone marrow and adipose tissue. Depending on the tissue of origin, MSCs have different characteristics and physiological effects. In various cancer studies, MSCs have been found to have either tumor-promoting or tumor-inhibiting action. This study investigated the effect of adipose tissue-MSCs (AT-MSCs) and bone marrow-MSCs (BM-MSCs) on global long interspersed nuclear element-1 (LINE-1) methylation, the expression level of microenvironment remodeling genes and cell proliferation, migration and invasion of oral tongue squamous cell carcinoma (OTSCC). Additionally, we studied the effect of human tongue squamous carcinoma (HSC-3)-conditioned media on LINE-1 methylation and the expression of microenvironment remodeling genes in AT-MSCs and BM-MSCs. Conditioned media from HSC-3 or MSCs did not affect LINE-1 methylation level in either cancer cells or MSCs, respectively. In HSC-3 cells, no effect of MSCs-conditioned media was detected on the expression of ICAM1, ITGA3 or MMP1 . On the other hand, HSC-3-conditioned media upregulated ICAM1 and MMP1 expression in both types of MSCs. Co-cultures of AT-MSCs with HSC-3 did not induce proliferation, migration or invasion of the cancer cells. In conclusion, AT-MSCs, unlike BM-MSCs, seem not to participate in oral cancer progression.

Background: Insufficient vascularization hampers bone tissue engineering strategies for reconstructing large bone defects. Delivery of prolyl-hydroxylase inhibitors (PHIs) is an interesting approach to upregulate vascular endothelial growth factor (VEGF) by mimicking hypoxic stabilization of hypoxia-inducible factor-1alpha (HIF-1α). This study assessed two PHIs: dimethyloxalylglycine (DMOG) and baicalein for their effects on human adipose tissue-derived mesenchymal stem/stromal cells (AT-MSCs)., Methods: Isolated AT-MSCs were characterized and treated with PHIs to assess the cellular proliferation response. Immunostaining and western-blots served to verify the HIF-1α stabilization response. The optimized concentrations for long-term treatment were tested for their effects on the cell cycle, apoptosis, cytokine secretion, and osteogenic differentiation of AT-MSCs. Gene expression levels were evaluated for alkaline phosphatase (ALPL), bone morphogenetic protein 2 (BMP2), runt-related transcription factor 2 (RUNX2), vascular endothelial growth factor A (VEGFA), secreted phosphoprotein 1 (SPP1), and collagen type I alpha 1 (COL1A1). In addition, stemness-related genes Kruppel-like factor 4 (KLF4), Nanog homeobox (NANOG), and octamer-binding transcription factor 4 (OCT4) were assessed., Results: PHIs stabilized HIF-1α in a dose-dependent manner and showed evident dose- and time dependent antiproliferative effects. With doses maintaining proliferation, DMOG and baicalein diminished the effect of osteogenic induction on the expression of RUNX2, ALPL, and COL1A1, and suppressed the formation of mineralized matrix. Suppressed osteogenic response of AT-MSCs was accompanied by an upregulation of stemness-related genes., Conclusion: PHIs significantly reduced the osteogenic differentiation of AT-MSCs and rather upregulated stemness-related genes. PHIs proangiogenic potential should be weighed against their longterm direct inhibitory effects on the osteogenic differentiation of AT-MSCs.

Methylation-specific probe amplification (MSPA) is a simple and robust technique that can be used to detect relative differences in methylation levels of DNA samples. It is resourceful, requires small amounts of DNA, and takes around 4-5 h of hands-on work. In the presented technique, DNA samples are first denatured then hybridized to probes that target DNA at either methylated or reference sites as a control. Hybridized DNA is separated into parallel reactions, one undergoing only ligation and the other undergoing ligation followed by HhaI-mediated digestion at unmethylated GCGC sequences. The resultant DNA fragments are amplified by PCR and separated by capillary electrophoresis. Methylated GCGC sites are not digested by HhaI and produce peak signals, while unmethylated GCGC sites are digested and no peak signals are generated. Comparing the control-normalized peaks of digested and undigested versions of each sample provides the methylation dosage ratio of a DNA sample. Here, MSPA is used to detect the effects of osteosarcoma-derived extracellular vesicles (EVs) on the methylation status of long interspersed nuclear element-1 (LINE-1) in mesenchymal stem cells. LINE-1s are repetitive DNA elements that typically undergo hypomethylation in cancer and, in this capacity, may serve as a biomarker. Ultracentrifugation is also used as a cost-effective method to separate extracellular vesicles from biological fluids (i.e., when preparing EV-depleted fetal bovine serum [FBS] and isolating EVs from osteosarcoma conditioned media [differential centrifugation]). For methylation analysis, custom LINE-1 probes are designed to target three methylation sites in the LINE-1 promoter sequence and seven control sites. This protocol demonstrates the use of MSPA for LINE-1 methylation analysis and describes the preparation of EV-depleted FBS by ultracentrifugation.

In the research field of extracellular vesicles (EVs), the use of fetal bovine serum (FBS) depleted of EVs for in vitro studies is advocated to eliminate the confounding effects of media derived EVs. EV-depleted FBS may either be prepared by ultracentrifugation or purchased commercially. Nevertheless, these preparations do not guarantee an RNA-free FBS for in vitro use. In this study we address the RNA contamination issue, of small non-coding (nc)RNA in vesicular or non-vesicular fractions of FBS, ultracentrifugation EV-depleted FBS, commercial EV-depleted FBS, and in our recently developed filtration based EV-depleted FBS. Commercially available serum- and xeno-free defined media were also screened for small ncRNA contamination. Our small ncRNA sequencing data showed that all EV-depleted media and commercially available defined media contained small ncRNA contaminants. Out of the different FBS preparations studied, our ultrafiltration-based method for EV depletion performed the best in depleting miRNAs. Certain miRNAs such miR-122 and miR-203a proved difficult to remove completely and were found in all media. Compared to miRNAs, other small ncRNA (snRNA, Y RNA, snoRNA, and piRNA) were difficult to eliminate from all the studied media. Additionally, our tested defined media contained miRNAs and other small ncRNAs, albeit at a much lower level than in serum preparations. Our study showed that no media is free of small ncRNA contaminants. Therefore, in order to screen for baseline RNA contamination in culturing media, RNA sequencing data should be carefully controlled by adding a media sample as a control. This should be a mandatory step before performing cell culture experiments in order to eliminate the confounding effects of media.

Extracellular vesicles (EVs) are central to intercellular communication and play an important role in cancer progression and development. Osteosarcoma (OS) is an aggressive bone tumour, characterized by the presence of malignant mesenchymal cells. The specific tumour-driving genetic alterations that are associated with OS development are currently poorly understood. Mesenchymal stem cells (MSCs) of osteogenic lineage have been postulated as likely candidates as the cells of origin for OS, thus indicating that MSCs and OS stroma cells may be related cell types. Therefore, this study set out to examine the EV-mediated intercellular crosstalk of MSCs and OS. MSCs and pre-osteoblasts were treated with OS-EVs at different time points, and the epigenetic signature of OS-EVs was assessed by methylation analysis of LINE-1 (long interspersed element) and tumour suppressor genes. In addition, surface markers and expression of specific genes were also evaluated. Our data indicated that OS-EVs mediated LINE-1 hypomethylation in MSCs, whereas an opposite effect was seen in pre-osteoblasts, indicating that MSCs but not pre-osteoblasts were susceptible to epigenetic transformation. Thus, OS-EVs modulated the fate of MSCs by modulating the epigenetic status, and also influenced the expression of genes related to bone microenvironment remodelling. Overall, this study provided evidence that epigenetic regulation appears to be an early event in the transformation of MSCs during the development of OS. Elucidating the mechanisms of EV-mediated communication may lead to new avenues for therapeutic exploitation.

Extracellular vesicles (EVs) are reported to be involved in stem cell maintenance, self-renewal, and differentiation. Due to their bioactive cargoes influencing cell fate and function, interest in EVs in regenerative medicine has rapidly increased. EV-derived small non-coding RNA mimic the functions of the parent stem cells, regulating the maintenance and differentiation of stem cells, controlling the intercellular regulation of gene expression, and eventually affecting the cell fate. In this study, we used RNA sequencing to provide a comprehensive overview of the expression profiles of small non-coding transcripts carried by the EVs derived from human adipose tissue stromal/stem cells (AT-MSCs) and human pluripotent stem cells (hPSCs), both human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSC). Both hPSCs and AT-MSCs were characterized and their EVs were extracted using standard protocols. Small non-coding RNA sequencing from EVs showed that hPSCs and AT-MSCs showed distinct profiles, unique for each stem cell source. Interestingly, in hPSCs, most abundant miRNAs were from specific miRNA families regulating pluripotency, reprogramming and differentiation (miR-17-92, mir-200, miR-302/367, miR-371/373, CM19 microRNA cluster). For the AT-MSCs, the highly expressed miRNAs were found to be regulating osteogenesis (let-7/98, miR-10/100, miR-125, miR-196, miR-199, miR-615-3p, mir-22-3p, mir-24-3p, mir-27a-3p, mir-193b-5p, mir-195-3p). Additionally, abundant small nuclear and nucleolar RNA were detected in hPSCs, whereas Y- and tRNA were found in AT-MSCs. Identification of EV-miRNA and non-coding RNA signatures released by these stem cells will provide clues towards understanding their role in intracellular communication, and well as their roles in maintaining the stem cell niche.

Intercellular communication is essential in bone remodelling to ensure that new bone is formed with only temporary bone loss. Monocytes (MCs) and osteoclasts actively take part in controlling bone remodelling by providing signals that promote osteogenic differentiation of mesenchymal stem/stromal cells (MSCs). Extracellular vesicles (EVs) have attracted attention as regulators of bone remodelling. EVs facilitate intercellular communication by transferring a complex cargo of biologically active molecules to target cells. In the present study, we evaluated the potency of EVs from MCs and osteoclasts to induce a lineage-specific response in MSCs. We analysed gene expression and protein secretion by both adipose tissue-derived MSCs and bone marrow-derived MSCs after stimulation with EVs from lipopolysaccharide-activated primary human MCs and (mineral-resorbing) osteoclasts. Isolated EVs were enriched in exosomes (EVs of endosomal origin) and were free of cell debris. MC- and osteoclast-derived EVs were taken up by adipose tissue-derived MSCs. EVs from activated MCs promoted the secretion of cytokines by MSCs, which may represent an immunomodulatory mechanism. MC-derived EVs also upregulated the expression of genes encoding for matrix metalloproteinases. Therefore, we hypothesize that MCs facilitate tissue remodelling through EV-mediated signalling. We did not observe a significant effect of osteoclast-derived EVs on gene expression or protein secretion in MSCs. EV-mediated signalling might represent an additional mode of cell-cell signalling during the transition from injury and inflammation to bone regeneration and play an important role in the coupling between bone resorption and bone formation., Database: Gene expression data are available in the GEO database under the accession number GSE102401., (© 2018 Federation of European Biochemical Societies.)

Fetal bovine serum (FBS) is the most commonly used supplement in studies involving cell-culture experiments. However, FBS contains large numbers of bovine extracellular vesicles (EVs), which hamper the analyses of secreted EVs from the cell type of preference and, thus, also the downstream analyses. Therefore, a prior elimination of EVs from FBS is crucial. However, the current methods of EV depletion by ultracentrifugation are cumbersome and the commercial alternatives expensive. In this study, our aim was to develop a protocol to completely deplete EVs from FBS, which may have wide applicability in cell-culture applications. We investigated different EV-depleted FBS prepared by our novel ultrafiltration-based protocol, by conventionally used overnight ultracentrifugation, or commercially available depleted FBS, and compared them with regular FBS. All sera were characterized by nanoparticle tracking analysis, electron microscopy, Western blotting and RNA quantification. Next, adipose-tissue mesenchymal stem cells (AT-MSCs) and cancer cells were grown in the media supplemented with the three different EV-depleted FBS and compared with cells grown in regular FBS media to assess the effects on cell proliferation, stress, differentiation and EV production. The novel ultrafiltration-based protocol depleted EVs from FBS clearly more efficiently than ultracentrifugation and commercial methods. Cell proliferation, stress, differentiation and EV production of AT-MSCs and cancer cell lines were similarly maintained in all three EV-depleted FBS media up to 96 h. In summary, our ultrafiltration protocol efficiently depletes EVs, is easy to use and maintains cell growth and metabolism. Since the method is also cost-effective and easy to standardize, it could be used in a wide range of cell-culture applications helping to increase comparability of EV research results between laboratories., Competing Interests: No potential conflict of interest was reported by the authors.

Urethral defects are normally reconstructed using a patient's own genital tissue; however, in severe cases, additional grafts are needed. We studied the suitability of poly(l-lactide-co-ɛ-caprolactone) (PLCL) and poly(trimethylene carbonate) (PTMC) membranes for urethral reconstruction in vivo. Further, the compatibility of the materials was evaluated in vitro with human urothelial cells (hUCs). The attachment and viability of hUCs and the expression of different urothelial cell markers (cytokeratin 7, 8, 19, and uroplakin Ia, Ib, and III) were studied after in vitro cell culture on PLCL and PTMC. For the in vivo study, 32 rabbits were divided into the PLCL (n = 15), PTMC (n = 15), and control or sham surgery (n = 2) groups. An oval urethral defect 1 × 2 cm in size was surgically excised and replaced with a PLCL or a PTMC membrane or urethral mucosa in sham surgery group. The rabbits were followed for 2, 4, and 16 weeks. After the follow-up, urethrography was performed to check the patency of the urethra. The defect area was excised for histological examination, where the epithelial integrity and structure, inflammation, and fibrosis were observed. There was no notable difference on hUCs attachment on PLCL and PTMC membranes after 1 day of cell seeding, further, the majority of hUCs were viable and maintained their urothelial phenotype on both biomaterials. Postoperatively, animals recovered well, and no severe strictures were discovered by urethrography. In histological examination, the urothelial integrity and structure developed toward a normal urothelium with only mild signs of fibrosis or inflammation. According to these results, PLCL and PTMC are both suitable for reconstructing urethral defects. There were no explicit differences between the PLCL and PTMC membranes. However, PTMC membranes were more flexible, easier to suture and shape, and developed significant epithelial integrity.

Objective: Oral lichen planus (OLP) and lichenoid lesions (OLL) are regarded as precursor lesions of oral squamous cell carcinoma (OSCC) with potential for malignant transformation. This potential is not clear due to difficulties in diagnosis of OLP and OLL. Our aim was therefore to evaluate previously identified OLP and OLL as precursor lesions in OSCC and to identify cancer related etiological factors such as smoking and alcohol consumption., Material and Methods: We retrospectively reviewed all cases (total 323, comprising 164 females and 159 males) with OSCC treated at the Department of Oral and Maxillofacial Diseases and Surgery, Helsinki University Hospital during 2015. Confirmed by histopathological biopsy, 58 (17.9%) had OLP and 13 had OLL (4.0%) as precursor lesion., Results: Patients with OLP were slightly older than those without it. OLP was more common in females than in males (p < .0001). TN class 1 tumors were more prevalent among patients with OLP or OLL (p = .006) and cancer relapses less common (p = .005). Smoking was less frequent in patients with OLP and OLL (p < .0001). Also alcohol abuse was less frequent among these patients (p < .001)., Conclusion: Our findings confirm the importance of active follow-up of all patients with OLP and OLL even in patients who do not fit a traditional high-risk category for OSCC.

Several alternative techniques exist to reconstruct skull defects. The complication rate of the cranioplasty procedure is high and the search for optimal materials and techniques continues. To report long-term results of patients who have received a cranioplasty using autologous adipose-derived stem cells (ASCs) seeded on beta-tricalcium phosphate (betaTCP) granules. Between 10/2008 and 3/2010, five cranioplasties were performed (four females, one male; average age 62.0 years) using ASCs, betaTCP granules and titanium or resorbable meshes. The average defect size was 8.1 × 6.7 cm 2 . Patients were followed both clinically and radiologically. The initial results were promising, with no serious complications. Nevertheless, in the long-term follow-up, three of the five patients were re-operated due to graft related problems. Two patients showed marked resorption of the graft, which led to revision surgery. One patient developed a late infection (7.3 years post-operative) that required revision surgery and removal of the graft. One patient had a successfully ossified graft, but was re-operated due to recurrence of the meningioma 2.2 years post-operatively. One patient had an uneventful clinical follow-up, and the cosmetic result is satisfactory, even though skull x-rays show hypodensity in the borders of the graft. Albeit no serious adverse events occurred, the 6-year follow-up results of the five cases are unsatisfactory. The clinical results are not superior to results achieved by conventional cranial repair methods. The use of stem cells in combination with betaTCP granules and supporting meshes in cranial defect reconstruction need to be studied further before continuing with clinical trials. Stem Cells Translational Medicine 2017;6:1576-1582., (© 2017 The Authors Stem Cells Translational Medicine published by Wiley Periodicals, Inc. on behalf of AlphaMed Press.)

We investigated the use of polypyrrole (PPy)-coated polymer scaffolds and electrical stimulation (ES) to differentiate adipose stem cells (ASCs) towards smooth muscle cells (SMCs). Since tissue engineering lacks robust and reusable 3D ES devices we developed a device that can deliver ES in a reliable, repeatable, and cost-efficient way in a 3D environment. Long pulse (1 ms) or short pulse (0.25 ms) biphasic electric current at a frequency of 10 Hz was applied to ASCs to study the effects of ES on ASC viability and differentiation towards SMCs on the PPy-coated scaffolds. PPy-coated scaffolds promoted proliferation and induced stronger calponin, myosin heavy chain (MHC) and smooth muscle actin (SMA) expression in ASCs compared to uncoated scaffolds. ES with 1 ms pulse width increased the number of viable cells by day 7 compared to controls and remained at similar levels to controls by day 14, whereas shorter pulses significantly decreased viability compared to the other groups. Both ES protocols supported smooth muscle expression markers. Our results indicate that electrical stimulation on PPy-coated scaffolds applied through the novel 3D ES device is a valid approach for vascular smooth muscle tissue engineering.

Growing number of musculoskeletal defects increases the demand for engineered tendon. Our aim was to find an efficient strategy to produce tendon-like matrix in vitro. To allow efficient differentiation of human adipose stem cells (hASCs) toward tendon tissue, we tested different medium compositions, biomaterials, and scaffold structures in preliminary tests. This is the first study to report that medium supplementation with 50 ng/mL of growth and differentiation factor-5 (GDF-5) and 280 μM l-ascorbic acid are essential for tenogenic differentiation of hASCs. Tenogenic medium (TM) was shown to significantly enhance tendon-like matrix production of hASCs compared to other tested media groups. Cell adhesion, proliferation, and tenogenic differentiation of hASCs were supported on braided poly(l/d)lactide (PLA) 96l/4d copolymer filament scaffolds in TM condition compared to foamed poly(l-lactide-co-ɛ-caprolactone) (PLCL) 70L/30CL scaffolds. A uniform cell layer formed on braided PLA 96/4 scaffolds when hASCs were cultured in TM compared to maintenance medium (MM) condition after 14 days of culture. Furthermore, total collagen content and gene expression of tenogenic marker genes were significantly higher in TM condition after 2 weeks of culture. The elastic modulus of PLA 96/4 scaffold was more similar to the elastic modulus reported for native Achilles tendon. Our study showed that the optimized TM is needed for efficient and rapid in vitro tenogenic extracellular matrix production of hASCs. PLA 96/4 scaffolds together with TM significantly stimulated hASCs, thus demonstrating the potential clinical relevance of this novel and emerging approach to tendon injury treatments in the future.

Epigenetic alterations such as DNA methylation, histone modifications and non-coding RNA (including microRNA) associated gene silencing have been identified as a major characteristic in human cancers. These alterations may occur more frequently than genetic mutations and play a key role in silencing tumor suppressor genes or activating oncogenes, thereby affecting multiple cellular processes. In recent years, studies have shown that microRNAs, that act as posttranscriptional regulators of gene expression are frequently deregulated in colorectal cancer (CRC), via aberrant DNA methylation. Over the past decade, technological advances have revolutionized the field of epigenetics and have led to the identification of numerous epigenetically dysregulated miRNAs in CRC, which are regulated by CpG island hypermethylation and DNA hypomethylation. In addition, aberrant DNA methylation of miRNA genes holds a great promise in several clinical applications such as biomarkers for early screening, prognosis, and therapeutic applications in CRC.