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Chronic, non-healing, dermal wounds form a worldwide medical problem with limited and inadequate treatment options and high societal burden and costs. With the advent of regenerative therapies exploiting extracellular matrix (ECM) components, its efficacy to augment wound healing is to be explored. This systematic review was performed to assess and compare the current therapeutic efficacy of ECM hydrogels on dermal wound healing. The electronic databases of Embase, Medline Ovid, and Cochrane Central were searched for in vivo and clinical studies on the therapeutic effect of ECM-composed hydrogels on dermal wound healing (April 13, 2021). Two reviewers selected studies independently. Studies were assessed based on ECM content, ECM hydrogel composition, additives, and wound healing outcomes, such as wound size, angiogenesis, and complications. Of the 2102 publications, 9 rodent-based studies were included while clinical studies were not published at the time of the search. Procedures to decellularize tissue or cultured cells and subsequently generate hydrogels were highly variable and in demand of standardization. ECM hydrogels with or without additives reduced wound size and also seem to enhance angiogenesis. Serious complications were not reported. To date, preclinical studies preclude to draw firm conclusions on the efficacy and working mechanism of ECM-derived hydrogels on dermal wound healing. The use of ECM hydrogels can be considered safe. Standardization of decellularization protocols and implementation of quality and cytotoxicity controls will enable obtaining a generic and comparable ECM product. Impact statementExtracellular matrix (ECM)-based hydrogels are biocompatible and harbor growth factors that can instruct tissue healing. Their application is a novelty in (pre)clinical wound healing treatment. This systematic review provides an overview of the current evidence for ECM hydrogels in enhancing wound healing and an extensive overview of the decellularization procedures used. Lastly, challenges and future directions to standardize decellularization procedures and implement quality controls are proposed.

Background Chronic obstructive pulmonary disease (COPD) is characterized by irreversible lung tissue damage. Novel regenerative strategies are urgently awaited. Cultured mesenchymal stem/stromal cells (MSCs) have shown promising results in experimental models of COPD, but differences between sources may impact on their potential use in therapeutic strategies in patients. Aim To assess the transcriptome of lung-derived MSCs (LMSCs), bone marrow-derived MSCs (BM-MSC) and adipose-derived MSCs (AD-MSCs) from COPD patients and non-COPD controls. Methods We studied differences in gene expression profiles between the MSC-subtypes, as well as between COPD and control using RNA sequencing (RNA-seq). Results We show that besides heterogeneity between donors, MSCs from different sources have strongly divergent gene signatures. The growth factors FGF10 and HGF were predominantly expressed in LMSCs. MSCs from all sources displayed altered expression profiles in COPD, with most pronounced significantly up- and downregulated genes in MSCs from adipose tissue. Pathway analysis revealed that the most differentially expressed genes in COPD-derived AD-MSCs are involved in extracellular matrix (ECM) binding and expression. In LMSCs, the gene that differed most strongly between COPD and control was CSGALNACT1, an ECM modulating gene. Conclusion Autologous MSCs from COPD patients display abnormalities with respect to their transcriptome, which were surprisingly most profound in MSCs from extrapulmonary sources. LMSCs may be optimally equipped for lung tissue repair because of the expression of specific growth factor genes.

Background Autologous lipofilling is an emerging procedure to treat and possibly reverse dermal scars and to reduce scar-related pain, but its efficacy and mechanisms are poorly understood. Objectives The aim of this study was to test the hypothesis that repeated lipografts reverse dermal scars by reinitiation of wound healing. Methods In a prospective, non-placebo-controlled clinical study, 27 adult patients with symptomatic scars were given 2 lipofilling treatments at 3-month intervals. As primary outcome, clinical effects were measured with the Patient and Observer Scar Assessment Scale (POSAS). Scar biopsies were taken before and after treatments to assess scar remodeling at a cellular level. Results Twenty patients completed the study. Patients’ scars improved after lipofilling. The total POSAS scores (combined patient and observer scores) decreased from 73.2 [14.7] points (mean [standard deviation]) pretreatment to 46.1 [14.0] and 32.3 [13.2] points after the first and second lipofilling treatment, respectively. Patient POSAS scores decreased from 37.3 [8.8] points to 27.2 [11.3] and 21.1 [11.4] points, whereas observer POSAS scores decreased from 35.9 [9.5] points to 18.9 [6.0] and 11.3 [4.5] points after the first and second treatment, respectively. After each lipofilling treatment, T lymphocytes, mast cells, and M2 macrophages had invaded scar tissue and were associated with increased vascularization. In addition, the scar-associated epidermis showed an increase in epidermal cell proliferation to levels similar to that normal in skin. Moreover, lipofilling treatment caused normalization of the extracellular matrix organization towards that of normal skin. Conclusions Autologous lipofilling improves the clinical outcome of dermal scars through the induction of a pro-regenerative immune response, increased vascularization, and epidermal proliferation and remodeling of scar tissue extracellular matrix. Level of Evidence: 4

In recent decades, adipose tissue transplantation has become an essential treatment modality for tissue (volume) restoration and regeneration. The regenerative application of adipose tissue has only recently proven its usefulness; for example, the method is useful in reducing dermal scarring and accelerating skin-wound healing. The therapeutic effect is ascribed to the tissue stromal vascular fraction (tSVF) in adipose tissue. This consists of stromal cells, the trophic factors they secrete and the extracellular matrix (ECM), which have immune-modulating, pro-angiogenic and anti-fibrotic properties. This concise review focused on dermal regeneration using the following adipose-tissue components: adipose-tissue-derived stromal cells (ASCs), their secreted trophic factors (ASCs secretome), and the ECM. The opportunities of using a therapeutically functional scaffold, composed of a decellularized ECM hydrogel loaded with trophic factors of ASCs, to enhance wound healing are explored as well. An ECM-based hydrogel loaded with trophic factors combines all regenerative components of adipose tissue, while averting the possible disadvantages of the therapeutic use of adipose tissue, e.g., the necessity of liposuction procedures with a (small) risk of complications, the impossibility of interpatient use, and the limited storage options.

Background In the last decades, autologous fat grafting has been used to treat adherent dermal scars. The observed regenerative and scar-reducing properties have been mainly ascribed to the tissue-derived stromal vascular fraction (tSVF) in adipose tissue. Adipose tissue’s components augment local angiogenesis and mitosis in resident tissue cells. Moreover, it promotes collagen remodeling. We hypothesize that tSVF potentiates fat grafting-based treatment of adherent scars. Therefore, this study aims to investigate the effect of tSVF-enriched fat grafting on scar pliability over a 12-month period. Methods and design A clinical multicenter non-randomized early phase trial will be conducted in two dedicated Dutch Burn Centers (Red Cross Hospital, Beverwijk, and Martini Hospital, Groningen). After informed consent, 46 patients (≥18 years) with adherent scars caused by burns, necrotic fasciitis, or degloving injury who have an indication for fat grafting will receive a sub-cicatricic tSVF-enriched fat graft. The primary outcome is the change in scar pliability measured by the Cutometer between pre- and 12 months post-grafting. Secondary outcomes are scar pliability (after 3 months), scar erythema, and melanin measured by the DSM II Colormeter; scar quality assessed by the patient and observer scales of the Patient and Observer Scar Assessment Scale (POSAS) 2.0; and histological analysis of scar biopsies (voluntary) and tSVF quality and composition. This study has been approved by the Dutch Central Committee for Clinical Research (CCMO), NL72094.000.20. Conclusion This study will test the clinical efficacy of tSVF-enriched fat grafting to treat dermal scars while the underlying working mechanism will be probed into too. Trial registration Dutch Trial Register NL 8461. Registered on 16 March 2020

Tissue engineering of skeletal muscle aims to replicate the parallel alignment of myotubes on the native tissue. Directional topography gradients allow the study of the influence of topography on cellular orientation, proliferation, and differentiation, resulting in yield cues and clues to develop a proper in vitro environment for muscle tissue engineering. In this study, we used a polydimethylsiloxane-based substrate containing an aligned topography gradient with sinusoidal features ranging from wavelength (lambda) = 1,520 nm and amplitude (A) =176 nm to lambda = 9,934 nm and A = 2,168 nm. With this topography gradient, we evaluated the effect of topography on human myoblasts distribution, dominant orientation, cell area, nuclei coverage, cell area per number of nuclei, and nuclei area of myotubes. We showed that human myoblasts aligned and differentiated irrespective of the topography section. In addition, aligned human myotubes showed functionality and maturity by contracting spontaneously and nuclei peripheral organization resembling natural myotubes.

Background Adipose tissue has been widely used in regenerative surgery for its therapeutic potential. This potential is often ascribed to the stromal vascular fraction (SVF), which can be mechanically isolated. Mechanical isolation results in an SVF that retains intact cell-cell communication including extracellular matrix and is therefore named tissue-SVF (tSVF). Objectives The aim of this study was to evaluate a new disposable 1-hole fractionator for fractionation of adipose tissue (FAT), and compare this new device with the existing reusable 3-hole fractionator. Methods The composition of tSVF obtained via the 1-hole fractionator was histologically and histochemically compared to unprocessed adipose tissue. The number of viable nuclear cells in tSVF obtained by the 1-hole and 3-hole fractionators as well as unprocessed adipose tissue were compared after enzymatic isolation and tested for colony-forming capacity. Flow cytometry was used to compare different cell compositions based on surface marker expression between tSVF isolated by the two types of fractionators. Results Fractionation of adipose tissue with the 1-hole fractionator condenses vasculature and extracellular matrix by disrupting adipocytes. The number of viable nuclear cells in tSVF obtained with the two fractionators was comparable and significantly higher than unprocessed lipoaspirate. Furthermore, tSVF isolated by both fractionators showed similar cell compositions and comparable colony-forming capacities. Conclusions FAT with a disposable 1-hole fractionator effectively isolates tSVF with a cell count and cell composition comparable to the fraction obtained with the 3-hole reusable fractionator. The disposable 1-hole fractionator, however, is safer and more user friendly.

In teeth with an injured pulp, dentin matrix orchestrates hard tissue repair through the release of dentin extracellular matrix components (dEMCs). dEMCs regulate the differentiation of resident mesenchymal stromal cells (MSCs), thereby affecting mineral deposition. In this study, we show that low-concentration solubilized dEMCs in osteogenic cultures of human umbilical cord mesenchymal stromal cells (UC-MSCs) and dental pulp stromal cells (DPSCs) enhanced mineral deposition, while adipose stromal cells (ASCs) were barely affected. Interestingly, UC-MSCs displayed significantly greater hydroxyapatite formation compared with DPSCs. UC-MSCs and DPSCs showed a dose-dependent viability and proliferation, whereas proliferation of ASCs remained unaffected. Qualitative analysis of the dEMC-supplemented osteogenic cultures through scanning electron microscopy demonstrated differences in the architecture of the deposited mineralized structures. Large-sized mineral accretions on a poorly organized collagen network were the prominent feature of UC-MSC cultures, while mineral nodules interspersed throughout a collagen mesh were observed in the respective DPSC cultures. The ability of dEMCs to induce mineralization varies between different human MSC types in terms of total mineral formation and architecture. Mineral formation by UC-MSCs exposed to low-concentration dEMCs proved to be the most efficient and therefore could be considered a promising combination for mineralized tissue engineering. Impact Statement This research has been conducted with the aim to contribute to the development of treatment modalities for the reconstruction of lost/damaged mineralized tissues. Currently, determining the most appropriate stromal cell population and signaling cues stands at the core of developing effective treatments. We provide new insights into the effect of innate inductive cues found in human dentin matrix components, on the osteogenic differentiation of various human stromal cell types. The effects of dentin extracellular matrix components on umbilical cord mesenchymal stromal cells have not been investigated before. The findings of this study could underpin translational research based on the development of techniques for mineralized tissue engineering and will be of great interest for the readership of Tissue Engineering Part A.

Endothelial-mesenchymal transition occurs during intimal hyperplasia and neointima formation via mechanisms that are incompletely understood. Endothelial MAPK7 signaling is a key mechanosensitive factor that protects against endothelial-mesenchymal transition, but its signaling activity is lost in vessel areas that are undergoing pathological remodeling. At sites of vascular remodeling in mice and pigs, endothelial MAPK7 signaling was lost. The TGFβ-induced microRNA-374b targets MAPK7 and its downstream effectors in endothelial cells, and its expression induces endothelial-mesenchymal transition. Gain-of-function experiments, where endothelial MAPK7 signaling was restored, precluded endothelial-mesenchymal transition. In human coronary artery disease, disease severity is associated with decreased MAPK7 expression levels and increased miR-374b expression levels. Endothelial-mesenchymal transition occurs in intimal hyperplasia and early lesion formation and is governed in part by microRNA-374b-induced silencing of MAPK7 signaling. Restoration of MAPK7 signaling abrogated these pathological effects in endothelial cells expressing miR-374b. Thus, our data suggest that the TGFβ-miR-374b-MAPK7 axis plays a key role in the induction of endothelial-mesenchymal transition during intimal hyperplasia and early lesion formation and might pose an interesting target for antiatherosclerosis therapy. © 2018 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Rationale: The airways in chronic obstructive pulmonary disease (COPD) are characterized by inflammation, goblet cell hyperplasia, decreased ciliated cell numbers and airway remodeling with an altered composition/deposition of the extracellular matrix (ECM). We aimed to develop a lung ECM hydrogel-based spatiotemporal model to investigate bidirectional interactions with fibroblasts and epithelial cells in relation to ECM changes. Methods: Porcine lungs were decellularized, lyophilized, ground into a powder, porcine pepsin-solubilized for 48h, buffered with PBS, pH neutralized and gelated at 37°C for 30min. Non-diseased primary lung fibroblasts (250,000 per ml) were mixed with hydrogels in transwells. After 24h the hydrogels were coated with Matrigel®, Collagen type IV or left uncoated. After 24h, 90,000 non-diseased primary bronchial epithelial cells (PBEC) were seeded on top. The hydrogels were imaged using light microscopy, stained for live and dead cells and paraffin embedded for histology. Results: The fibroblasts inside the ECM hydrogels were viable for up to 5 days, displaying a spindle-shaped morphology. The Matrigel and Collagen IV formed a thin layer on top of the ECM hydrogel which was visualized by a collagen IV immunohistochemical staining. The PBECs grew to a confluent layer in 3-5 days on top of the coated and non-coated ECM hydrogels with no apparent difference in the PBEC layer between them. Conclusions: The lung ECM hydrogel in combination with a basement membrane like coating allowed for the co-culture of primary lung fibroblasts and PBECs in their correct dimensionality resembling the airway in vivo. The next step is to expose the apical surface of the PBEC layer to air to stimulate the development of a mucociliated epithelial layer.

Magnesium (Mg) is a material widely used in industrial applications due to its low weight, ductility, and excellent mechanical properties. For non-permanent implants, Mg is particularly well-suited because of its biodegradability, while its degradation products are not harmful. However, Mg is chemically reactive, and cytotoxic hydrogen gas is released as part of the degradation. This adverse degradation can be tuned using plasma electrolytic oxidation (PEO). With PEO, a surface layer of MgO/Mg(OH)(2) is deposited on the surface of Mg in a controlled way. The electrolytes used during PEO influence the surface's chemistry and topography and thus expectedly the biological response of adhered cells. In this study, thin samples of commercial pure of Mg (c.p Mg) were modified by PEO guided by different electrolytes, and the biological activity was assessed on vascular cells, immune cells, and repair cells (adipose tissue-derived stromal cells, ASCs). Vascular cells were more vulnerable than ASCs for compounds released by surface-coated Mg. All surface coatings supported the proliferation of adhered ASC. Released compounds from surface-coated Mg delayed but did not block in vitro wound closure of fibroblasts monolayers. Preformed endothelial tubes were vulnerable for released compounds, while their supporting ASC was not. We conclude that PEO-based surface-coating of Mg supports adhesion and future delivery of therapeutic vascular repair cells such as ASC, but that the observed vulnerability of vascular cells for coated Mg components warrants investigations in vivo.

One of the most common magnesium (Mg) applications in the biomedical field is in cardiovascular stents. Although Mg is an essential element for homeostasis, Mg is highly reactive, and locally high Mg concentrations can have toxic effects on the surrounding tissue. One strategy to circumvent the Mg toxicity is using coatings or surface modifications that prevent the leaching of excessive Mg ions. In the current study, commercially pure magnesium (c.p Mg) was modified through plasma electrolytic oxidation (PEO) to produce a protective coating primarily composed of Mg oxide (MgO) and Mg hydroxide (Mg(OH)2), which limits leaching of free Mg ions from the base material. As we intend to use this material to produce vascular stents, a biological evaluation of its performance is warranted. Primary human umbilical vein endothelial cells (HUVECs) and smooth muscle cells (SMCs) were the study object. The leaching of free Mg ions from the oxidized materials was investigated, as was its effect on local pH changes. We also investigated the influence of corrosion products, the effects of elevated free Mg concentrations and pH on the cellular behavior on the integrity of monolayers of HUVECs was studied in a static and dynamic model. Results showed that the harmful effect of Mg on cells due to changes in pH and a high concentration of Mg ions could decrease with the influence of flow diffusing corrosion products such as MgO, Mg(OH)2, and H2 among the system. Independently, Mg concentration and pH affected the cell activity of SMCs and HUVECs. Finally, to investigate the influence of leachables on vasomotor function, we exposed porcine aortic rings to PEO-modified Mg stents and assessed endothelial-dependent relaxation. Pure Mg reduced vasorelaxation from 100% in control samples to 30%. Oppositely, PEO-modified Mg did not affect the vasomotor function. Overall, we conclude from this study that the use of PEO coatings reduces the degradation rate of the material reducing the Mg release resulting in better cell viability and vessel function compared to the bare material.

Abdominal aortic aneurysm (AAA) is the pathological dilation and weakening of the abdominal aorta wall. Inflammation, degradation of the extracellular matrix (ECM) and loss of smooth muscle cells and skewing of their function are pivotal in AAA pathology. We developed a recombinant collagen-based patch (RCP) to provide structural integrity and deliver Adipose tissue-Derived Stromal Cells (ASC) for repair. Patches supported adhesion and function as well as proliferation of ASC. ASC-loaded RCPs or bare patches, applied around the aorta after AAA induction in rats, both maintained structural integrity of the aortic wall at time of explant (2w). However, wall thinning, accompanied by loss of elastin fibers and loss of medial SMC, was only attenuated in ASC-loaded RCP-treated AAA rats. Interestingly, this coincided with migration of ASC into the media and a reduced influx of macrophages. We hypothesize that the medially-migrated ASC dampened or skewed the adverse innate immunity and thus suppressed SMC apoptosis, phenotypic skewing and elastin degradation. We conclude that the periadventitial delivery of ASC with RCP suppresses development and progression of AAA, which is has an expected future clinical benefit in combination with an appropriate early screening program of patients at risk for aneurysms. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A:2494-2506, 2018.

Atherosclerosis is an inflammatory disease resulting in the hardening and thickening of the wall of arteries and the formation of plaques, which comprise immune cells, mesenchymal cells, lipids, and extracellular matrix. The source of mesenchymal cells in the atherosclerotic plaques has been under scrutiny for years. Current endothelial-lineage tracing studies indicate that the endothelium is a source for plaque-associated mesenchymal cells. Endothelial cells can acquire a mesenchymal phenotype through endothelial-mesenchymal transition (EndMT), wherein the expression of endothelial markers and functions is lost and the expression of mesenchymal cell marker and functions acquired. Furthermore, EndMT can result in delamination and migration of endothelial cell-derived mesenchymal cells into the underlying tissue. Here, we review the contribution of EndMT in vascular disease focusing on atherosclerosis and describe the major biochemical and biomechanical signalling pathways in EndMT during atherosclerosis progression. Furthermore, we address how the well-established systemic atherosclerosis risk factors might facilitate EndMT during atherosclerosis.

Animal experimentation requires a solid and rational moral foundation. Objective and emphatic decision-making and protocol evaluation by researchers and ethics committees remain a difficult and sensitive matter. This article presents three perspectives that facilitate a consideration of the minimally acceptable standard for animal experiments, in particular, in tissue engineering (TE) and regenerative medicine. First, we review the boundaries provided by law and public opinion in America and Europe. Second, we review contemporary moral theory to introduce the Neo-Rawlsian contractarian theory to objectively evaluate the ethics of animal experiments. Third, we introduce the importance of available reduction, replacement, and refinement strategies, which should be accounted for in moral decision-making and protocol evaluation of animal experiments. The three perspectives are integrated into an algorithmic and graphic harm-benefit analysis tool based on the most relevant aspects of animal models in TE. We conclude with a consideration of future avenues to improve animal experiments.

Long-term diabetes leads to macrovascular and microvascular complication. In diabetic retinopathy (DR), persistent hyperglycemia causes permanent loss of retinal pericytes and aberrant proliferation of microvascular endothelial cells (ECs). Adipose tissue-derived stromal cells (ASCs) may serve to functionally replace retinal pericytes and normalize retinal microvasculature during disease progression. We hypothesized that Notch signaling in ASC underlies regulation and stabilization of dysfunctional retinal microvascular networks such as in DR. ASC prominently and constitutively expressed NOTCH2. Genetic knockdown of NOTCH2 in ASC (SH-NOTCH2) disturbed the formation of vascular networks of human umbilical cord vein endothelial cells both on monolayers of ASC and in organotypical three-dimensional cocultures with ASC. On ASC SH-NOTCH2, cell surface platelet-derived growth factor receptor beta was downregulated which disrupted their migration toward the chemoattractant platelet-derived growth factor beta subunits (PDGF-BB) as well as to conditioned media from EC and bovine retinal EC. This chemoattractant is secreted by pro-angiogenic EC in newly formed microvascular networks to attract pericytes. Intravitreal injected ASC SH-NOTCH2 in oxygen-induced retinopathy mouse eyes did not engraft in the preexisting retinal microvasculature. However, the in vivo pro-angiogenic capacity of ASC SH-NOTCH2 did not differ from controls. In this respect, multifocal electroretinography displayed similar b-wave amplitudes in the avascular zones when either wild type ASC or SH-NOTCH2 ASC were injected. In conclusion, our results indicate that NOTCH2 is essential to support in vitro vasculogenesis via juxtacrine interactions. In contrast, ongoing in vivo angiogenesis is influenced by paracrine signaling of ASC, irrespective of Notch signaling.

Intraoperative application of the stromal vascular fraction (SVF) of adipose tissue requires a fast and efficient isolation procedure of adipose tissue. This review was performed to systematically assess and compare procedures currently used for the intraoperative isolation of cellular SVF (cSVF) and tissue SVF (tSVF) that still contain the extracellular matrix. Pubmed, EMBASE and the Cochrane central register of controlled trials databases were searched for studies that compare procedures for intraoperative isolation of SVF (searched 28 September 2016). Outcomes of interest were cell yield, viability of cells, composition of SVF, duration, cost and procedure characteristics. Procedures were subdivided into procedures resulting in a cSVF or tSVF. Thirteen out of 3038 studies, evaluating 18 intraoperative isolation procedures, were considered eligible. In general, cSVF and tSVF intraoperative isolation procedures had similar cell yield, cell viability and SVF composition compared to a nonintraoperative (i.e. culture laboratory-based collagenase protocol) control group within the same studies. The majority of intraoperative isolation procedures are less time consuming than nonintraoperative control groups, however. Intraoperative isolation procedures are less time-consuming than nonintraoperative control groups with similar cell yield, viability of cells and composition of SVF, and therefore more suitable for use in the clinic. Nevertheless, none of the intraoperative isolation procedures could be designated as the preferred procedure to isolate SVF. Copyright © 2017 John Wiley & Sons, Ltd.

Lipofilling or lipografting is a novel and promising treatment method for reduction or prevention of dermal scars after injury. Ample anecdotal evidence from case reports supports the scar-reducing properties of adipose tissue grafts. However, only a few properly controlled and designed clinical trials have been conducted thus far on this topic. Also, the underlying mechanism by which lipofilling improves scar aspect and reduces neuropathic scar pain remains largely undiscovered. Adipose-derived stromal or stem cells (ADSC) are often described to be responsible for this therapeutic effect of lipofilling. We review the recent literature and discuss anticipated mechanisms that govern anti-scarring capacity of adipose tissue and its ADSC. Both clinical and animal studies clearly demonstrated that lipofilling and ADSC influence processes associated with wound healing, including extracellular matrix remodelling, angiogenesis and modulation of inflammation in dermal scars. However, randomized clinical trials, providing sufficient level of evidence for lipofilling and/or ADSC as an anti-scarring treatment, are lacking yet warranted in the near future. © 2017 The Authors Journal of Tissue Engineering and Regenerative Medicine Published by John Wiley & Sons Ltd.

The number of diabetic patients in Europe and world-wide is growing. Diabetes confers a 2-fold higher risk for vascular disease. Lack of insulin production (Type 1 diabetes, T1D) or lack of insulin responsiveness (Type 2 diabetes, T2D) causes systemic metabolic changes such as hyperglycemia (HG) which contribute to the pathology of diabetes. Monocytes and macrophages are key innate immune cells that control inflammatory reactions associated with diabetic vascular complications. Inflammatory programming of macrophages is regulated and maintained by epigenetic mechanisms, in particular histone modifications. The aim of our study was to identify the epigenetic mechanisms involved in the hyperglycemia-mediated macrophage activation. Using Affymetrix microarray profiling and RT-qPCR we identified that hyperglycemia increased the expression of S100A9 and S100A12 in primary human macrophages. Expression of S100A12 was sustained after glucose levels were normalized. Glucose augmented the response of macrophages to Toll-like receptor (TLR)-ligands Palmatic acid (PA) and Lipopolysaccharide (LPS) i.e., pro-inflammatory stimulation. The abundance of activating histone Histone 3 Lysine 4 methylation marks (H3K4me1, H3K4me3) and general acetylation on histone 3 (AceH3) with the promoters of these genes was analyzed by chromatin immunoprecipitation. Hyperglycemia increased acetylation of histones bound to the promoters of S100A9 and S100A12 in M1 macrophages. In contrast, hyperglycemia caused a reduction in total H3 which correlated with the increased expression of both S100 genes. The inhibition of histone methyltransferases SET domain-containing protein (SET)7/9 and SET and MYND domain-containing protein (SMYD)3 showed that these specifically regulated S100A12 expression. We conclude that hyperglycemia upregulates expression of S100A9, S100A12 via epigenetic regulation and induces an activating histone code on the respective gene promoters in M1 macrophages. Mechanistically, this regulation relies on action of histone methyltransferases SMYD3 and SET7/9. The results define an important role for epigenetic regulation in macrophage mediated inflammation in diabetic conditions.

Introduction Endothelial cells play a pivotal role in the formation of neointimal lesions by the acquisition of a fibro-proliferative phenotype through endothelial-to-mesenchymal transition (EndMT). Uniform laminar shear stress activates the mitogen-activated protein kinase 7 (MAPK7) which suppresses EndMT. It is elusive how MAPK7 activity is regulated in fibroproliferative disease. We recently found in intimal hyperplasia the signaling activity of MAPK7 is rapidly lost through the activation microRNA-374b. The histone methyltransferase Enhancer of Zeste Homolog 2 (EZH2), which is the catalytic subunit of the Polycomb Repressive Complex 2, plays a pivotal role in endothelial dysfunction. EZH2 trimethylates lysine 27 on histone 3, which silences gene expression and is elevated in endothelial cells in atherosclerotic lesions. Here, we found the reciprocity that exists between MAPK7 and EZH2 in the regulation of EndMT and in human coronary artery stenosis. Materials and results In endothelial cells, activation of MAPK7 increases the expression of microRNA-101, which represses the expression of EZH2. Reciprocally, the loss of EZH2 coincides with a decreased expression of the Dual Specificity Phosphatase (DUSP)-1 and DUSP-6 – the phosphatases responsible for the dephosphorylation of MAPK7 - which facilitates the activation of MAPK7. H3K27Me3, the repressive histone mark placed by EZH2, is abundantly present in the promoter regions of the miR-200b/a/429 and miR-200c/141 gene clusters, which are responsible for the loss of DUSP-1 and DUSP-6 expression. Endothelial cells deficient in EZH2 have reduced levels of H3K27Me3 at these gene promoters, which associates with the increased expression of miR-200b and miR-200c and concurrent increased MAPK7 activation. In endothelial cells with constitutively active MAPK7 signaling (MEK5D), the enrichment of H3K27Me3 at the promoter regions of miR-200b/a/429 (1.6-fold, p=0.034) and miR-200c/141 (1.9-fold, p=0.035) is decreased, suggesting that MAPK7 activation results in a decreased EZH2 activity. Disbalances in this reciprocal signaling circuit culminate in the induction of EndMT and associate to the severity of human coronary artery stenosis. Conclusion In summary, we show that in endothelial cells there is reciprocity between MAPK7 signaling and EZH2 expression and that disturbances in this reciprocal signaling circuit associate with the induction of EndMT and severity of human coronary artery stenosis. The reciprocity between MAPK7 and EZH2 is governed by a complex mechanism involving microRNAs and the phosphatases DUSP-1 and DUSP-6. Our study contributes to a better understanding of the molecular and epigenetic cascades that underlie EndMT during coronary artery stenosis and might identify novel targets for therapy. Acknowledgement/Funding Mongolian Government Scholarship #621

Rationale: The biomechanics of human lung tissue is strongly influenced by the composition of the extracellular matrix (ECM). The effect of storage (freezing and subsequent thawing) on biomechanics and ECM in lung tissue is as yet not known. The aim of this study was to evaluate if storing human lung tissue frozen or frozen in Tissue-Tek® O.C.T.™ changed its mechanical properties. Methods: Pieces of human explanted lung (nondiseased n=4, COPD IV n=3 and pulmonary fibrosis n=1) were stored cooled (4°C), frozen fresh, or frozen in Tissue-Tek® O.C.T.™ (-20°C) for 24 to 48h. Tissues were warmed to room temperature, washed 3x with HBSS and mechanical properties assessed using a low load compression tester measuring stiffness and viscoelastic stress relaxation. Measurements were obtained from 3 locations per tissue piece with 1 piece per storage method per donor. Results: No differences in stiffness and stress relaxation were found between the fresh tissue and tissue frozen either fresh or in O.C.T. (Table 1). Conclusions: The stiffness and viscoelasticity of human nondiseased and diseased lung tissue were unaltered by freeze-thawing. These findings open up the possibility to use human lung tissue stored in biobanks in order to study the involvement of ECM and biomechanics in lung disease.

Lipofilling, the transplantation of adipose tissue, has already been used since the end of the 19th century. For decades, lipofilling was used to restore loss of volume due to aging, trauma, or congenital defects. Later on, the indications for the use of lipofilling expanded by treating aged skin, scars, and improving wound healing. The expansion was caused by the discovery of adipose derived stromal cells (ASCs) in adipose tissue and the development of very fine harvesting and injection cannulas which made it possible to inject small adipose tissue particles in small volume areas, such as the face. ASCs are multipotent stromal cells which reside in the stromal vascular fraction (SVF) of adipose tissue and are able to differentiate in multiple cell lineages and secrete a plurality of growth factors with regenerative potentials. The discovery of ASCs led toward more experimental cell-based therapies, that is, ASCs or SVF isolated by means of enzymatic isolation procedures. Later on, enzymatic isolation procedures were forbidden in many countries by legislation and were replaced by mechanical isolation procedures, such as the Nanofat and Fractionation of Adipose Tissue (FAT) procedures. The Nanofat procedure has been extensively investigated, especially as treatment for skin rejuvenation in the face. Though, substantial evidence is lacking for using facial lipofilling or any therapeutic component, that is, ASCs or SVF for skin rejuvenation to date. In contrast, facial lipofilling to restore loss of volume seems to be promising.

Adipose tissue-derived stromal cells (ASCs) are a promising candidates for cellular therapy in the field of regenerative medicine. ASCs are multipotent mesenchymal stem cell-like and reside in the stromal vascular fraction (SVF) of adipose tissue with the capacity to secrete a plethora of pro-regenerative growth factors. Future applications of ASCs may be restricted through (trans)national governmental policies that do not allow for use of nonhuman-derived (non-autologous) enzymes to isolate ASC. Besides, enzymatic isolation procedures are also time consuming. To overcome this issue, nonenzymatic isolation procedures to isolate ASCs or the SVF are being developed, such as the fractionation of adipose tissue procedure (FAT). This standardized procedure to isolate the stromal vascular fraction can be performed within 10-12 min. The short procedure time allows for intraoperative isolation of 1 mL of stromal vascular fraction derived from 10 mL of centrifuged adipose tissue. The stromal vascular fraction mostly contains blood vessels, extracellular matrix, and ASCs. However, based on the histological stainings an interdonor variation exists which might result in different therapeutic effects. The existing interdonor variations can be addressed by histological stainings and flow cytometry.

BACKGROUND: Autologous lipografting for improvement of facial skin quality was first described by Coleman in 2006. The current dogma dictates that adipose tissue-derived stromal cells that reside in the stromal vascular fraction of lipograft contribute to skin rejuvenation (e.g., increased skin elasticity), a more homogenous skin color, and softening of skin texture. Nowadays, many studies have been reported on this "skin rejuvenation" effect of autologous fat grafting. This systematic review was undertaken to assess the efficacy of autologous lipografting on skin quality.METHODS: The MEDLINE, Embase, Cochrane Central, Web of Science, and Google Scholar databases were searched for studies evaluating the effect of autologous lipografting on facial skin quality (May 11, 2018). Outcomes of interest were skin texture, color, and elasticity in addition to histologic outcomes and number of complications.RESULTS: Nine studies were included, with 301 patients treated in total. No meta-analysis could be performed because of heterogeneity of the metrics and outcomes. Eight studies reported increased skin elasticity; improvement in skin texture; and a more homogeneous skin color after treatment with lipografting, cellular stromal vascular fraction, or nanofat. One study reported no increased skin elasticity after lipografting. Histologic improvement was seen after lipografting and adipose tissue-derived stromal cell injections. However, in general, the level of evidence of the included studies was low. No serious complications were reported.CONCLUSION: Autologous facial lipografting and cellular stromal vascular fraction and adipose tissue-derived stromal cell injections hardly seem to improve facial skin quality but can be considered a safe procedure.

To mitigate pretransplantation injury in organs of potential donors, N-octanoyl dopamine (NOD) treatment might be considered as it does not affect hemodynamic parameters in braindead (BD) donors. To better assess optimal NOD concentrations for donor treatment, we report on the fast and facile radiofluorination of the NOD-derivative [F-18]F-NOD [F-18]5 for in vivo assessment of NOD's elimination kinetics by means of PET imaging. [F-18]5 was synthesized in reproducibly high radiochemical yields and purity (>98%) as well as high specific activities (>20 GBq/mu mol). Stability tests showed no decomposition of [F-18]5 over a period of 120 min in rat plasma. In-vitro, low cell association was found for [F-18]5, indicating no active transport mechanism into cells. In vivo, [F-18]5 exhibited a fast blood clearance and a predominant hepatobiliary elimination. As these data suggest that also NOD might be cleared fast, further pharmacokinetic evaluation is warranted.

Autologous adipose tissue transplantation is clinically used to reduce dermal scarring and to restore volume loss. The therapeutic benefit on tissue damage more likely depends on the stromal vascular fraction of adipose tissue than on the adipocyte fraction. This stromal vascular fraction can be obtained by dissociation of adipose tissue, either enzymatically or mechanical. Enzymatic dissociation procedures are time-consuming and expensive. Therefore, we developed a new inexpensive mechanical dissociation procedure to obtain the stromal vascular fraction from adipose tissue in a time sparing way, which is directly available for therapeutic injection. This mechanical dissociation procedure is denoted as the fractionation of adipose tissue (FAT) procedure. The FAT procedure was performed in eleven patients. The composition of the FAT-stromal vascular fraction was characterized by immunohistochemistry. Adipose derived stromal cells isolated from the FAT-stromal vascular fraction were compared with adipose derived stromal cells isolated from nondissociated adipose tissue (control) for their CD-surface marker expression, differentiation and colony forming unit capacity. Case reports demonstrated the therapeutic effect of the FAT-stromal vascular fraction. The FAT-stromal vascular fraction is an enrichment of extracellular matrix containing a microvasculature and culturable adipose derived stromal cells. Adipose derived stromal cells isolated from FAT-stromal vascular fraction did not differ from adipose derived stromal cells isolated from the control group in CD-surface marker expression, differentiation and colony forming unit capacity. The FAT procedure is a rapid effective mechanical dissociation procedure to generate FAT-stromal vascular fraction ready for injection with all its therapeutic components of adipose tissue: it contains culturable adipose derived stromal cells embedded in their natural supportive extracellular matrix together with the microvasculature.

Diabetic retinopathy (DR) is a hyperglycemia (HG)-mediated microvascular complication. In DR, the loss of pericytes and subsequently endothelial cells leads to pathologic angiogenesis in retina. Adipose-derived stromal cells (ASC) are a promising source of therapeutic cells to replace lost pericytes in DR. To date, knowledge of the influence of HG on the bioenergetics and pericytic function of ASC is negligible. Human ASC were cultured in normoglycemia medium (5mM d-glucose) or under HG (30mM D-glucose) and assessed. Our data showed that HG increased the level of apoptosis and reactive oxygen species production in ASC, yet their proliferation rate was not affected. HG induced alterations in mitochondrial function and morphology in ASC. HG also strongly affected the bioenergetic status of ASC in which both the maximum oxygen consumption rate and extracellular acidification rate were decreased. This was corroborated by a reduced uptake of glucose under HG. In spite of these observations, in vitro, ASC promoted the formation of vascular-like networks of human umbilical vein endothelial cells on monolayers of ASC under HG with minimally affected.

Female mice from independently bred lines previously selected over 50 generations for increased voluntary wheel-running behavior (S1, S2) resist high energy (HE) diet-induced obesity (DIO) at adulthood, even without actual access to running wheels, as opposed to randomly bred controls (CON). We investigated whether adult S mice without wheels remain DIO-resistant when exposed - via the mother - to the HE diet during their perinatal stage (from 2 weeks prior to conception until weaning on post-natal day 21). While S1 and S2 females subjected to HE diet either perinatally or from weaning onwards (post-weaning) resisted increased adiposity at adulthood (as opposed to CON females), they lost this resistance when challenged with HE diet during these periods combined over one single cycle of breeding. When allowed one-week access to wheels (at week 6-8 and at 10 months), however, tendency for increased wheel-running behavior of S mice was unaltered. Thus, the trait for increased wheel-running behavior remained intact following combined perinatal and post-weaning HE exposure, but apparently this did not block HE-induced weight gain. At weaning, perinatal HE diet increased adiposity in all lines, but this was only associated with hyperleptinemia in S lines irrespective of gender. Because leptin has multiple developmental effects at adolescence, we argue that a trait for increased physical activity may advance maturation in times of plenty. This would be adaptive in nature where episodes of increased nutrient availability should be exploited maximally. Associated disturbances in glucose homeostasis and related co-morbidities at adulthood are probably pleiotropic side effects. (C) 2016 Elsevier Inc. All rights reserved.

Understanding how endothelial cell phenotype is affected by topography could improve the design of new tools for tissue engineering as many tissue engineering approaches make use of topography-mediated cell stimulation. Therefore, we cultured human pulmonary microvascular endothelial cells (ECs) on a directional topographical gradient to screen the EC vascular-like network formation and alignment response to nano to microsized topographies. The cell response was evaluated by microscopy. We found that ECs formed unstable vascular-like networks that aggregated in the smaller topographies and flat parts whereas ECs themselves aligned on the larger topographies. Subsequently, we designed a mixed topography where we could explore the network formation and proliferative properties of these ECs by live imaging for three days. Vascular-like network formation continued to be unstable on the topography and were only produced on the flat areas and a fibronectin coating did not improve the network stability. However, an instructive adipose tissue-derived stromal cell (ASC) coating provided the correct environment to sustain the vascular-like networks, which were still affected by the topography underneath. It was concluded that large microsized topographies inhibit vascular endothelial network formation but not proliferation and flat and nano/microsized topographies allow formation of early networks that can be stabilized by using an ASC instructive layer., Bioengineering; Biophysics; Cell biology; Biomedical engineering; Regenerative medicine; Directional topography; Endothelial cells; Vascular-like networks; Contact guidance; Vascularization

Metal stents are used as base material for fabrication of medical devices to support and improve the quality of life of patients with cardiovascular diseases such as arterial stenoses. Permanently present implants may induce responses that resemble adverse wound healing that compromise tissue function. A similar process namely restenosis, frequently may occur after the use of this kind of implants. However, the use of non-permanent, resorbable stents are a promising option to avoid this problem. The advantage of these implants is that they can degraded upon vascular repair. The most common metal used for this application, is magnesium (Mg) which is an interesting material due its biological properties and because it is an essential element for human life. However, Mg-based resorbable biomaterial have some restrictions in clinical applications because its corrosion resistance, and mechanical properties. As solutions of this problem, the material can be modified in its composition (Mg-based alloys) or by surface treatments. This review shows and discusses recent challenges in the improvement of Mg-based biomaterials to be used to treat vascular disease and novel approaches at design-based biomaterials engineering of the same. Design-based methodologies are introduced and discussed in the context of balancing multi-functional properties against adaptation to the complex extreme in vivo environment. Traditional alloying approaches of Mg-based biomaterials are also discussed in the context of corrosion resistance controlled by surface modification strategies including conversion techniques: physicochemical or electrochemical transformation such as anodization, plasma and electrophoretic deposition.

Stem cell therapy is a promising approach for repair, remodeling and even regenerate tissue of otherwise irreparable damage, such as after myocardial infarction (aMI). A severe limitation of cardiac stem cell therapy is the generally poor retention of administered cells in the target tissue. In tissue repair the main mode of action of adipose tissue-derived stem cells (ADSC) is the production of various growth factors, cytokines, anti-inflammatory and anti-apoptotic factors that together augment repair, remodeling, and regeneration. In this experiment, we used recombinant collagen peptide (RCP) with additional integrin-binding motives and different crosslinkers. Formulated as 50-100 μm microspheres with bound ADSC, we hypothesized that this would improve ADSC retention and function. Crosslinking was performed with chemical crosslinkers (EDC and HMDIC) at high and low concentrations or by thermal treatment (DHT). ADSC adhesion, proliferation, apoptosis/necrosis, and gene expressions in two-dimensional and three-dimensional were analyzed. In addition, the effect of ADSC conditioned medium (ADSC-CM) on proapoptotic/sprouting HUVEC was examined. Our results show that all materials support cell adhesion in short time point, however, EDC-High crosslinker induced ADSC apoptosis/necrosis. Gene expression results revealed lower expression of proinflammatory genes in chemical crosslinked materials, despite EDC-High the proinflammatory genes expressions were similar or higher than TCPS. In addition, cultured ADSC on DHT crosslinked RCP showed a proinflammatory phenotype compared to TCPS. Sprouting assay results confirmed the protective effect of ADSC-CM derived from TCPS and HMDIC-High crosslinked RCP proapoptotic HUVEC. We conclude that ADSC adhere to the materials and maintain their therapeutic profile.

Smooth muscle-22 alpha (SM22 alpha), encoded by transgelin (TAGLN), is expressed in mesenchymal lineage cells, including myofibroblasts and smooth muscle cells. It is an F-actin binding protein that regulates the organization of actin cytoskeleton, cellular contractility and motility. SM22 alpha is crucial for the maintenance of smooth muscle cell phenotype and its function. SM22 alpha is also expressed in the processes of mesenchymal transition of epithelial (EMT) or endothelial cells (EndMT). The expression of TAGLN/SM22 alpha is induced by transforming growth factor-beta (TGF beta) signaling and enhanced by concomitant interleukin-1 beta (IL-1 beta) signaling. We investigated the epigenetic regulation of TAGLN expression by enhancer of zeste homolog-2 (EZH2), the methyltransferase of Polycomb, in the context of TGF beta and IL-1 beta signaling in endothelial cells. We demonstrate that the expression of EZH2 in endothelial cells was regulated by the inflammatory cytokine IL-1 beta. A decrease in both expression and activity of EZH2 led to an increase in TAGLN expression. Inhibition of EZH2 augmented TGF beta 2-induced SM22 alpha expression. The decrease of EZH2 levels in endothelial cells co-stimulated with IL-1 beta and TGF beta 2 correlated with decreased H3K27me3 levels at the TAGLN proximal promoter. Moreover, the SM22 alpha expression increased. Taken together, this suggests that EZH2 regulates the chromatin structure at the TAGLN promoter through tri-methylation of H3K27. EZH2 therefore acts as an epigenetic integrator of IL-1 beta and TGF beta 2 signaling, providing an example of how cellular signaling can be resolved at the level of epigenetic regulation. Since IL-1 beta and TGF beta 2 represent the pro-inflammatory and pro-fibrotic conditions during vascular fibroproliferative disease, we surmise that EZH2, as the molecule that integrates their signaling, could also be a promising target for development of future therapy. (C) 2015 Elsevier Inc. All rights reserved.

Nanotubular structures were generated on the surface of titanium c.p. by anodization technique in an aqueous solution of acetic acid (14% v/v) with different sources of fluoride ion (HF, NaF, NH

Diabetic retinopathy (DR) is a multifactorial microvascular disease induced by hyperglycemia and subsequent metabolic abnormalities. The resulting cell stress causes a sequela of events that ultimately can lead to severe vision impairment and blindness. The early stages are characterized by activation of glia and loss of pericytes, endothelial cells (EC) and neuronal cells. The integrity of the retinal microvasculature becomes affected, and, as a possible late response, macular edema may develop as a common reason for vision loss in patients with non-proliferative DR. Moreover, the local ischemia can trigger vasoproliferation leading to vision-threating proliferative DR (PDR) in humans. Available treatment options include control of metabolic and hemodynamic factors. Timely intervention of advanced DR stages with laser photocoagulation, intraocular anti–vascular endothelial growth factor (VEGF) or glucocorticoid drugs can reduce vision loss. As the pathology involves cell loss of both the vascular and neuroglial compartments, cell replacement strategies by stem and progenitor cells have gained considerable interest in the past years. Compared to other disease entities, so far little is known about the efficacy and potential mode of action of cell therapy in treatment of DR. In preclinical models of DR different cell types have been applied ranging from embryonic or induced pluripotent stem cells, hematopoietic stem cells, and endothelial progenitor cells to mesenchymal stromal cells (MSC). The latter cell population can combine various modes of action (MoA), thus they are among the most intensely tested cell types in cell therapy. The aim of this review is to discuss the rationale for using MSC as potential cell therapy to treat DR. Accordingly, we will revise identified MoA of MSCs and speculate how these may support the repair of the damaged retina.

Monocytes are actively recruited at sites of chronic inflammation. However, molecular factors involved in this process are not fully elucidated. Here, we show that cytokine IL-4 which is implicated in the development of chronic inflammatory disease atopic dermatitis (AD) induces expression of transcription factor FoxQ1 in human monocytes and macrophages. FoxQ1 mRNA levels were elevated in monocytes of AD patients compared to healthy donors. Overexpression of FoxQ1 in RAW 264.7 monocytic cells facilitated their migration towards MCP-1 and was associated with decreased expression of migration-regulating genes (claudin 11 and plexin C1). Furthermore, FoxQ1 overexpression in RAW cells accelerated TNFα secretion after LPS challenge. Overall, our results indicate that FoxQ1 stimulates monocyte motility, increases pro-inflammatory potential, and directs monocyte migration towards MCP-1 that is crucial for monocyte influx into inflammatory sites. This mechanism could contribute to the pathogenesis of chronic inflammatory disorders such as AD.

Adipose derived stromal cells (ADSC) are relevant therapeutic agents to treat myocardial infarction (MI) in clinical trials. Soluble factors secreted by ADSC, such as growth factors and cytokines, suppress inflammation and apoptosis while promoting angiogenesis and the proliferation of cardiomyocytes (CM). Moreover, ADSC synthesize extracellular matrix (ECM) components into the intercellular space which might contribute to their therapeutic capacity. Thus, ADSC might directly modulate the post-MI microenvironment through a combination of paracrine and juxtacrine signaling. In this study, the juxtacrine role of ADSC and ADSC-derived ECM on the organization and maturation of CM was investiagated. Human ADSC synthesized and deposited a heterogenous and complex mixture of ECM components such as collagen I, III, IV, fibronectin, elastin as well as the matricellular protein periostin. Cocultures of rodent CM with human ADSC or with human ADSC-derived ECM components enhanced the cardiomyocyte alignment, their intercellular connections and the maturation of their sarcomeres, while the proliferation rate of the CM was increased and their level of hypertrophy reduced. The use of human ADSC-derived ECM could serve both to augment in vitro tissue-engineered myocardial constructs and to improve myocardial remodeling after infarction. (c) 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 1840-1848, 2015.

The pandemic of cardiovascular disease is continuously expanding as the result of changing life styles and diets throughout the Old and New World. Immediate intervention therapy saves the lives of many patients after acute myocardial infarction (MI). However, for many this comes at the price of adverse cardiac remodeling and heart failure. Currently, no conventional therapy can prevent the negative aftermath of MI and alternative treatments are warranted. Therefore, cardiac stem cell therapy has been put forward over the past decade, albeit with modest successes. Mesenchymal Stem Cells (MSC) are promising because these are genuine cellular factories of a host of secreted therapeutic factors. MSC are obtained from bone marrow or adipose tissue (ADSC). However, the heart itself also contains mesenchymal- like stem cells, though more difficult to acquire than ADSC. Interestingly, mesenchymal cells such as fibroblasts can be directly or indirectly reprogrammed to all myocardial cell types that require replacement after MI. To date, the paracrine and juxtacrine mechanisms of ADSC and other MSC on vessel formation are best understood. The preconditioning of, otherwise naive, stem cells is gaining more interest: previously presumed deleterious stimuli such as hypoxia and inflammation, i.e. causes of myocardial damage, have the opposite effect on mesenchymal stem cells. MSC gain a higher therapeutic capacity under hypoxia and inflammatory conditions. In this review, mesenchymal stem cells and their working mechanisms are put into the perspective of clinical cardiac stem cell therapy.

Pericytes in the retina differ from pericytes in many other organs by their high density and their cooperative role in the neurovascular unit. Their diverse ontogeny and the fact that not one pericyte marker identifies the entire population suggest also functional plurality in the retina, including invading cells of mesenchymal origin. Further, to establish factors determining pericyte recruitment, modifiers of pericyte adhesion and homeostasis, such as notch-3 and angptl-4, have been recently identified, expanding the understanding of pericyte function in the retina. Also, the role of pericytes as part of the neurovascular unit has been appreciated, given that the neuroglia determines pericyte survival and motility under disease conditions. Pericyte dropout is not unique in the diabetic retina, and non-diabetic animal models may prove useful in the search for mechanisms involved in disease-associated dysfunction of the neurovascular unit.

Form-stable resorbable networks are prepared by gamma irradiating trimethylene carbonate (TMC)- and e-caprolactone (CL)-based (co)polymer films. To evaluate their suitability for biomedical applications, their physical properties and erosion behavior are investigated. Homopolymer and copolymer networks that are amorphous at room temperature are flexible and rubbery with elastic moduli ranging from 1.8 ± 0.3 to 5.2 ± 0.4 MPa and permanent set values as low as 0.9% strain. The elastic moduli of the semicrystalline networks are higher and range from 61 ± 3 to 484 ± 34 MPa. The erosion behavior of (co)polymer networks is investigated in vitro using macrophage cultures, and in vivo by subcutaneous implantation in rats. In macrophage cultures, as well as upon implantation, a surface erosion process is observed for the amorphous (co)polymer networks, while an abrupt decrease in the rate and a change in the nature of the erosion process are observed with increasing crystallinity. These resorbable and form-stable networks with tuneable properties may find application in a broad range of biomedical applications.

To mitigate pretransplantation injury in organs of potential donors, N-octanoyl dopamine (NOD) treatment might be considered as it does not affect hemodynamic parameters in braindead (BD) donors. To better assess optimal NOD concentrations for donor treatment, we report on the fast and facile radiofluorination of the NOD-derivative [

Intraoperative application of the stromal vascular fraction (SVF) of adipose tissue requires a fast and efficient isolation procedure of adipose tissue. This review was performed to systematically assess and compare procedures currently used for the intraoperative isolation of cellular SVF (cSVF) and tissue SVF (tSVF) that still contain the extracellular matrix. Pubmed, EMBASE and the Cochrane central register of controlled trials databases were searched for studies that compare procedures for intraoperative isolation of SVF (searched 28 September 2016). Outcomes of interest were cell yield, viability of cells, composition of SVF, duration, cost and procedure characteristics. Procedures were subdivided into procedures resulting in a cSVF or tSVF. Thirteen out of 3038 studies, evaluating 18 intraoperative isolation procedures, were considered eligible. In general, cSVF and tSVF intraoperative isolation procedures had similar cell yield, cell viability and SVF composition compared to a nonintraoperative (i.e. culture laboratory-based collagenase protocol) control group within the same studies. The majority of intraoperative isolation procedures are less time consuming than nonintraoperative control groups, however. Intraoperative isolation procedures are less time-consuming than nonintraoperative control groups with similar cell yield, viability of cells and composition of SVF, and therefore more suitable for use in the clinic. Nevertheless, none of the intraoperative isolation procedures could be designated as the preferred procedure to isolate SVF. Copyright © 2017 John WileySons, Ltd.