Xenogenic Material Research Articles

LiQD Cornea: Pro-regeneration collagen mimetics as patches and alternatives to corneal transplantation.

Transplantation with donor corneas is the mainstay for treating corneal blindness, but a severe worldwide shortage necessitates the development of other treatment options. Corneal perforation from infection or inflammation is sealed with cyanoacrylate glue. However, the resulting cytotoxicity requires transplantation. LiQD Cornea is an alternative to conventional corneal transplantation and sealants. It is a cell-free, liquid hydrogel matrix for corneal regeneration, comprising short collagen-like peptides conjugated with polyethylene glycol and mixed with fibrinogen to promote adhesion within tissue defects. Gelation occurs spontaneously at body temperature within 5 min. Light exposure is not required-particularly advantageous because patients with corneal inflammation are typically photophobic. The self-assembling, fully defined, synthetic collagen analog is much less costly than human recombinant collagen and reduces the risk of immune rejection associated with xenogeneic materials. In situ gelation potentially allows for clinical application in outpatient clinics instead of operating theaters, maximizing practicality, and minimizing health care costs.

Composition of spherules and lower mantle minerals, isotopic and geochemical characteristics of zircon from volcaniclastic facies of the Mriya lamproite pipe

The article presents the results of studying the rocks of the pyroclastic facies of the Mriya lamproite pipe, located on the Priazovsky block of the Ukrainian shield. In them the rock's mineral composition includes a complex of exotic mineral particles formed under extreme reduction mantle conditions: silicate spherules, particles of native metals and intermetallic alloys, oxygen-free minerals such as diamond, qusongite (WC), and osbornite (TiN). The aim of the research is to establish the genesis of volcaniclastic rocks and to develop ideas of the highly deoxidized mantle mineral association (HRMMA), as well as to conduct an isotopic and geochemical study of zircon. As a result, groups of minerals from different sources are identified in the heavy fraction: HRMMA can be attributed to the juvenile magmatic component of volcaniclastic rocks; a group of minerals and xenoliths that can be interpreted as xenogenic random material associated with mantle nodules destruction (hornblendite, olivinite and dunite xenoliths), intrusive lamproites (tremolite-hornblende) and crystalline basement rocks (zircon, hornblende, epidote, and granitic xenoliths). The studied volcaniclastic rocks can be defined as intrusive pyroclastic facies (tuffisites) formed after the lamproites intrusion. Obviously, the HRMMA components formed under extreme reducing conditions at high temperatures, which are characteristic of the transition core-mantle zone. Thus, we believe that the formation of primary metal-silicate HRMMA melts is associated with the transition zone D".

Ridge preservation of compromised extraction sockets applying a soft cortical membrane: A canine proof-of-principle evaluation

ObjectivesTo explore whether placement of a soft cortical membrane can restore and regenerate the original alveolar ridge contour in deficient sockets. Materials and methodsOne Beagle dog was used in this proof-of-principle evaluation. In a first intervention, a standardized buccal dehiscence defect was artificially created at the distal roots of the 3rd and 4th mandibular premolars. Four weeks later, following endodontic treatment of the mesial roots, teeth were hemisected and the distal roots were extracted without raising a flap. A cortical membrane (Lamina®, Osteobiol) was placed outside of the bony envelope of the extraction socket to rebuild the buccal bone contour. Afterwards, sockets were filled with a collagen-modified porcine bone graft material (Gen-Os®, Osteobiol) to the level of the surrounding bone height. The socket orifice was closed with a porcine dermal matrix (Derma®). After four months, block specimens containing the socket-sites and remaining roots were retrieved, histologically processed and analyzed. ResultsSurgery and post-operative healing were uneventful. Histologically, bone formation under the membrane was found, i.e. bony protrusions and ossicles by osteoblasts could be identified. Concomitantly, the membrane showed clear signs of degradation. Bone substitute was well integrated in newly formed bone and resorption of particles was found. ConclusionThree major observations were made in the present proof-of-principle study: (i) regeneration of a compromised socket seems possible when applying the presented approach, (ii) the soft cortical membrane was sufficiently stable to allow for the establishment of the contour and to inhibit soft tissue invasion and (iii) the applied xenogenic graft material was undergoing remodelling processes while allowing adequate bone regeneration.

Anticipating Xenogenic Pollution at the Source: Impact of Sterilizations on DNA Release From Microbial Cultures.

The dissemination of DNA and xenogenic elements across waterways is under scientific and public spotlight due to new gene-editing tools, such as do-it-yourself (DIY) CRISPR-Cas kits deployable at kitchen table. Over decades, prevention of spread of genetically modified organisms (GMOs), antimicrobial resistances (AMR), and pathogens from transgenic systems has focused on microbial inactivation. However, sterilization methods have not been assessed for DNA release and integrity. Here, we investigated the fate of intracellular DNA from cultures of model prokaryotic (Escherichia coli) and eukaryotic (Saccharomyces cerevisiae) cells that are traditionally used as microbial chassis for genetic modifications. DNA release was tracked during exposure of these cultures to conventional sterilization methods. Autoclaving, disinfection with glutaraldehyde, and microwaving are used to inactivate broths, healthcare equipment, and GMOs produced at kitchen table. DNA fragmentation and PCR-ability were measured on top of cell viability and morphology. Impact of these methods on DNA integrity was verified on a template of free λ DNA. Intense regular autoclaving (121°C, 20 min) resulted in the most severe DNA degradation and lowest household gene amplification capacity: 1.28 ± 0.11, 2.08 ± 0.03, and 4.96 ± 0.28 logs differences to the non-treated controls were measured from E. coli, S. cerevisiae, and λ DNA, respectively. Microwaving exerted strong DNA fragmentation after 100 s of exposure when free λ DNA was in solution (3.23 ± 0.06 logs difference) but a minor effect was observed when DNA was released from E. coli and S. cerevisiae (0.24 ± 0.14 and 1.32 ± 0.02 logs differences with the control, respectively). Glutaraldehyde prevented DNA leakage by preserving cell structures, while DNA integrity was not altered. The results show that current sterilization methods are effective on microorganism inactivation but do not safeguard an aqueous residue exempt of biologically reusable xenogenic material, being regular autoclaving the most severe DNA-affecting method. Reappraisal of sterilization methods is required along with risk assessment on the emission of DNA fragments in urban systems and nature.

Re-endothelization of human saphenous vein scaffold surfaces for bioprosthesis fabrication

Various in vitro methods have been used for biological and synthetic scaffold fabrication. Some use polymers such as expanded polytetrafluoroethylene (ePTFE), polytetrafluoroethylene (PTFE), and polyethylene terephthalate (PET), while others use allogeneic or xenogeneic biological materials (e.g. blood vessels). While fabricating a biological scaffold, the first step is complete decellularization by enzymes (e.g. trypsin, collagenase, etc.) or chemicals (e.g. SDS, Triton-X, etc.), and the scaffolds should maintain its extracellular matrix (ECM). The second step involves re-endothelization so as to get fully biomimetic graft. In this study, we focused (concentrated) on the fabrication of a human saphenous vein scaffold by using various chemicals. We observed that cationic 1% SDS solution (Group B) performed excellent decellularization without altering the extracellular matrix as compared to the other chemicals like 0.25% trypsin and 70% ethanol (Groups C and D). Decellularization percentage and intactness of ECM (in all tunicae – intima, media, and adventitia) were confirmed based on histology. The PicoGreen assay showed that Group B (1% SDS decellularized scaffold, n = 3) had no detectable residual DNA. Re-endothelization on the complete decellularized scaffold (Group B) was done in both ways, without initial fibrin glue application (Group E) and with prior fibrin glue application (Group F). The vWF and lectin expressions suggested that endothelial cells did not alter their phenotype on human saphenous vein scaffolds. Uniaxial tensile testing revealed no significant differences in strain characteristics and modulus between native tissue and decellularized scaffolds. The live-dead (FDA/PI) and MTT assays confirmed the endothelial cell proliferation and viability, and the scanning electron microscope (SEM) data showed that the cells adhered to the scaffold matrix (Group F). We concluded that an allogeneic human saphenous vein scaffold with desirable properties can be fabricated and re-endothelialized to form a non-thrombogenic intimal surface in vitro using this protocol.

P.651 Mood congruent helplessness associates with prefrontal Intrinsic connectivity in major depression

In this work we have proposed to use multifractal analysis to evaluate the effectiveness of the healing process in postresectal and postcystal bone loss using the guided bone regeneration (GBR).The material of the study consists of 19 radiographic images obtained from patients (13 females and 6 males), observed within 1-year-long period, who had undergone bone augmentation with xenogenic material. Using radiographic images (RVG) made with digital radiography set Kodak RVG 6100 on the day of the procedure (Group A) and 12 months later (Group B), the degree of reconstruction of intraosseous defects were compared. A visual subjective evaluation of the healing process based on RVG images may not be sufficient. For this purpose, modern computer image analysis methods can be used. Pre-processing of radiographic images consisted of separating areas of interest (ROI) and binarization. The resulting images were analyzed using multifractals. The properties of biological structures cannot be sufficiently described in the Euclidean space, but they can be characterized by a parameter called the fractal dimension.Significant increase (p < 0.0001) of multifractal features were found in patients from group B. Individual parameters may characterize bone structure, which had undergone bone augmentation with xenogenic material. Finally, we showed that the properly selected multifractal quantificators obtained for those images could be used to assign those images to the appropriate group.The proposed analysis based on RVG images could help to evaluate the healing process after bone loss. The analysis and interpretation of the healing process after bone loss using monofractal and multifractal analysis as a multi-steps process quantify a stable (good) clinical result.

The Influence of Different Grafting Materials on Alveolar Ridge Preservation: a Systematic Review.

ABSTRACTObjectivesThe purpose of the present review was to evaluate the effect of different bone substitutes used for alveolar ridge preservation on the post extraction dimensional changes.Material and MethodsAn electronic literature search in MEDLINE (PubMed), EMBASE (OVID) and Cochrane (CENTRAL) were performed, in addition to a manual search through all periodontics and implantology-related journals, up to December 2018. Inverse variance weighted means were calculated for all the treatment arms of the included trials for the quantitative analysis.ResultsForty randomized controlled trials were included in the quantitative analysis. Dimensional changes were obtained from clinical measurements and three-dimensional imaging. The average amount of horizontal ridge resorption was 1.52 (SD 1.29) mm (allograft), 1.47 (SD 0.92) mm (xenograft), 2.31 (SD 1.19) mm (alloplast) and 3.1 (SD 1.07) mm for unassisted healing. Similarly, for all the evaluated parameters, the spontaneous healing of the socket led to higher bone loss rate than the use of a bone grafting material.ConclusionsThe utilization of a bone grafting material for alveolar ridge preservation reduces the resorption process occurring after tooth extraction. However, minimal differences in resorption rate were observed between allogeneic, xenogeneic and alloplastic grafting materials.

Surgical Treatment of Periodontal Diseases—a Review of Current Clinical Research

This manuscript reviews the literature concerning the surgical treatment of periodontal diseases focusing on studies published within the last three years (2016–2019). A thorough review of four databases was completed including clinical human research studies and systematic reviews. Several recent studies have focused on evaluating the effects of combining alloplastic materials with autologous platelet-rich products and growth factors. The results of most of these studies are similar to those with traditionally used allografts. New membranes of human, animal, stem cell, or alloplastic origin, used for guided tissue regeneration procedures, perform similarly to the traditionally used resorbable collagen membranes. Addition of pharmacologic agents to regenerative procedures presents moderately favorable results. Tissue engineering and stem cell research are also expanding, although most of these studies are in vitro or in animal models. Newer minimally invasive surgical techniques and equipment that allow for better visibility and less invasive surgical approach have shown favorable results. Finally, systematic reviews conclude that there is lack of evidence to support LASERs as an alternative to more traditional surgical periodontal treatment. The focus of many recent human clinical studies has been to evaluate the combination of alloplastic and xenogeneic materials with autologous platelet-rich products, growth factors, and pharmacologic agents. The results of these combinations are similar to traditionally used allografts. The great variability between study design, materials, and techniques highlights the need for well-designed randomized controlled trials and longitudinal studies.

Human cell-derived tissue-engineered heart valve with integrated Valsalva sinuses: towards native-like transcatheter pulmonary valve replacements

Transcatheter valve replacement indication is currently being extended to younger and lower-risk patients. However, transcatheter prostheses are still based on glutaraldehyde-fixed xenogeneic materials. Hence, they are prone to calcification and long-term structural degeneration, which are particularly accelerated in younger patients. Tissue-engineered heart valves based on decellularized in vitro grown tissue-engineered matrices (TEM) have been suggested as a valid alternative to currently used bioprostheses, showing good performance and remodeling capacity as transcatheter pulmonary valve replacement (TPVR) in sheep. Here, we first describe the in vitro development of human cell-derived TEM (hTEM) and their application as tissue-engineered sinus valves (hTESVs), endowed with Valsalva sinuses for TPVR. The hTEM and hTESVs were systematically characterized in vitro by histology, immunofluorescence, and biochemical analyses, before they were evaluated in a pulse duplicator system under physiological pulmonary pressure conditions. Thereafter, transapical delivery of hTESVs was tested for feasibility and safety in a translational sheep model, achieving good valve performance and early cellular infiltration. This study demonstrates the principal feasibility of clinically relevant hTEM to manufacture hTESVs for TPVR.

Efficacy of Xenogeneic Collagen Matrix to Augment Peri-Implant Soft Tissue Thickness Compared to Autogenous Connective Tissue Graft: A Systematic Review and Meta-Analysis.

Several approaches for increasing peri-implant mucosal thickness have been proposed, including autogenous, allogeneic, and xenogeneic grafts. The objective of this meta-analysis was to analyze whether xenogeneic matrices are viable alternatives to autogenous soft tissue grafts in peri-implant soft tissue augmentation. A systematic search was performed to select randomized clinical trials that compared connective tissue grafts and xenogeneic collagen matrices. The primary outcomes were the mucosal thickness and keratinized mucosa changes, while the secondary outcomes were patient morbidity, painkiller consumption, and surgical time required for the procedure. Seven randomized clinical trials were included for the final evaluation with a total number of 218 implant sites (108 in the connective tissue graft group, 110 in the collagen matrix group) with 3 to 12 months (mean: 6 months) follow-up period. Results showed mucosal thickness increase in both buccal and crestal sites, but it did not yield statistical significance. The keratinized mucosa gain difference was only -0.06 mm (95% CI [-30.0, 0.18]) between the treatments. The postsurgical discomfort, increased consumption of painkillers, and reduction of treatment time (15.46 minutes less) differed significantly in favor of the collagen matrix group. Within the limits of this study, it can be concluded that collagen matrix and connective tissue graft are equivalent in peri-implant soft tissue augmentation.

Efficacy of lateral bone augmentation performed simultaneously with dental implant placement: A systematic review and meta-analysis.

To analyse the evidence regarding the efficacy of lateral bone augmentation procedures in terms of defect resolution in cases of horizontal ridge deficiencies after implant placement. Included studies met the following inclusion criteria: randomized controlled trials (RCTs) or controlled clinical trials (CCTs), re-entry procedure to assess defect resolution, minimum of 10 patients (5 per group). Meta-analyses were performed whenever possible, including subgroup analysis based on membranes and grafting materials. Twenty-eight publications (20 short-term, 8 follow-up studies) were included. The most often used type of intervention was a xenogeneic particulated grafting material (XE) and a resorbable collagen membrane (CM). The mean defect height at baseline amounted to 5.1mm (range 2.4-7.8) and decreased to a mean of 0.9mm (range 0.2-2.2) at re-entry, and the mean defect resolution was 81.3% (range 56.4%-97.1%). Defect height reduction was not significantly different using CM+XE as control treatment compared to the combined data of the respective test groups [n=11; weighted mean difference (WMD)=-0.006mm; 95% CI, -0.61, 0.60; p=0.985]. The absence of any lateral bone augmentation was less favourable than the conjunction of a membrane and a bone grafting material (n=1; MD=-1.96mm; 95% CI, -3.48, -0.44; p=0.011). The lack of a grafting material was less favourable than the conjunction of grafting material and membrane (n=1; MD=-2.44mm; 95% CI, -4.53, -0.35; p=0.022), and the addition of a membrane compared to a grafting material alone was more favourable (n=3; WMD=0.97mm; 95% CI, 0.31, 1.64; p=0.004). Lateral bone augmentation is a successful treatment modality. For optimal defect height reduction, a barrier membrane and a grafting material should be combined.

Effect of alveolar ridge preservation interventions following tooth extraction: A systematic review and meta-analysis.

The aim of this systematic review was to critically analyse the available evidence on the effect of different modalities of alveolar ridge preservation (ARP) as compared to tooth extraction alone in function of relevant clinical, radiographic and patient-centred outcomes. A comprehensive search aimed at identifying pertinent literature for the purpose of this review was conducted by two independent examiners. Only randomized clinical trials (RCTs) that met the eligibility criteria were selected. Relevant data from these RCTs were collated into evidence tables. Endpoints of interest included clinical, radiographic and patient-reported outcome measures (PROMs). Interventions reported in the selected studies were clustered into ARP treatment modalities. All these different ARP modalities were compared to the control therapy (i.e. spontaneous socket healing) in each individual study after a 3- to 6-month healing period. Random-effects meta-analyses were conducted if at least two studies within the same ARP treatment modality reported on the same outcome of interest. A combined database, grey literature and hand search identified 3,003 records, of which 1,789 were screened after removal of duplicates. Following the application of the eligibility criteria, 25 articles for a total of 22 RCTs were included in the final selection, from which nine different ARP treatment modalities were identified: (a) bovine bone particles (BBP)+socket sealing (SS), (b) construct made of 90% bovine bone granules and 10% porcine collagen (BBG/PC)+SS, (c) cortico-cancellous porcine bone particles (CPBP)+SS, (d) allograft particles (AG)+SS, (e) alloplastic material (AP) with or without SS, (f) autologous blood-derived products (ABDP), (g) cell therapy (CTh), (h) recombinant morphogenic protein-2 (rhBMP-2) and (i) SS alone. Quantitative analyses for different ARP modalities, all of which involved socket grafting with a bone substitute, were feasible for a subset of clinical and radiographic outcomes. The results of a pooled quantitative analysis revealed that ARP via socket grafting (ARP-SG), as compared to tooth extraction alone, prevents horizontal (M=1.99mm; 95% CI 1.54-2.44; p<0.00001), vertical mid-buccal (M=1.72mm; 95% CI 0.96-2.48; p<0.00001) and vertical mid-lingual (M=1.16mm; 95% CI 0.81-1.52; p<0.00001) bone resorption. Whether there is a superior ARP or SS approach could not be determined on the basis of the selected evidence. However, the application of particulate xenogenic or allogenic materials covered with an absorbable collagen membrane or a rapidly absorbable collagen sponge was associated with the most favourable outcomes in terms of horizontal ridge preservation. A specific quantitative analysis showed that sites presenting a buccal bone thickness >1.0mm exhibited more favourable ridge preservation outcomes (difference between ARP [AG+SS] and control=3.2mm), as compared to sites with a thinner buccal wall (difference between ARP [AG+SS] and control=1.29mm). The effect of other local and systemic factors could not be assessed as part of the quantitative analyses. PROMs were comparable between the experimental and the control group in two studies involving the use of ABDP. The effect of other ARP modalities on PROMs could not be investigated, as these outcomes were not reported in any other clinical trial included in this study. Alveolar ridge preservation is an effective therapy to attenuate the dimensional reduction of the alveolar ridge that normally takes place after tooth extraction.

Human platelet lysate is suitable for the propagation of human bone marrow derived mesenchymal stromal cells

Background & Aim To evaluate the suitability of human platelet lysate (HPL) as a replacement for foetal bovine serum (FBS) for the propagation of human bone marrow derived mesenchymal stromal cells (MSCs). Background FBS is used universally as a cell culture supplement. Currently the use of FBS is still tolerated, however its use in clinical trials is tightly regulated and the US Food and Drug Administration (FDA) is moving towards adopting European guidelines, requiring that xenogeneic materials be eliminated in the preparation of any human therapeutic product containing cultured cells. Therefore, the use of HPL as a replacement for FBS in MSC expansion was evaluated. Methods, Results & Conclusion Methods Two types of HPL were produced by freeze-thawing and pooling either 12 units of expired apheresis platelet concentrates or 10 units of expired pooled platelet concentrates (n=3 batches each). MSCs from two donors were seeded at 5000 cells/cm2 and cultured to approximately 75-80% confluency using DMEM supplemented with either apheresis HPL, pooled HPL or FBS. Similar to FBS, HPL was heat-inactivated for 60 min at 56°C prior to addition to DMEM. The optimum concentration of HPL was determined by titration (2.5%, 5%, 7.5%, or 10%) against MSC culture expansion. Cell proliferation rates and doubling time were determined. Post-thaw immunophenotype and viability (7AAD) of BM-MSCs were determined by flow cytometry. Tri-lineage differentiation capacity was confirmed by microscopy after in vitro stimulation for either 14 days (chondrogenic and adipogenic) or 28 days (osteogenic). Results All 3 batches of HPL demonstrated an optimal culture concentration of 5% for apheresis HPL and 7.5 % for pooled HPL. Both types of HPL induced faster MSC proliferation when compared with matched 10% FBS controls. Apheresis HPL consistently outperformed pooled HPL, presumably as it is richer in growth factors. MSCs expanded under optimum conditions showed >90% expression of CD73, CD90 and CD105, and all were negative for CD45, CD34, CD19, CD11b, and HLA-DR. Mean 7AAD viability was 90% for MSCs grown in apheresis HPL, 88% for pooled HPL, and 84% for FBS. One batch of each type of HPL was used for tri-lineage differentiation capacity analysis. All MSCs were able to differentiate into either chondrogenic, osteogenic, or adipogenic lineages. Conclusion Apheresis and pooled HPL induced higher MSC expansion than FBS. The use of HPL as a substitute for FBS in MSC propagation warrants further investigation.

Multifractal characterization of healing process after bone loss

ObjectiveIn this work we have proposed to use multifractal analysis to evaluate the effectiveness of the healing process in postresectal and postcystal bone loss using the guided bone regeneration (GBR). MethodsThe material of the study consists of 19 radiographic images obtained from patients (13 females and 6 males), observed within 1-year-long period, who had undergone bone augmentation with xenogenic material. Using radiographic images (RVG) made with digital radiography set Kodak RVG 6100 on the day of the procedure (Group A) and 12 months later (Group B), the degree of reconstruction of intraosseous defects were compared. A visual subjective evaluation of the healing process based on RVG images may not be sufficient. For this purpose, modern computer image analysis methods can be used. Pre-processing of radiographic images consisted of separating areas of interest (ROI) and binarization. The resulting images were analyzed using multifractals. The properties of biological structures cannot be sufficiently described in the Euclidean space, but they can be characterized by a parameter called the fractal dimension. ResultsSignificant increase (p < 0.0001) of multifractal features were found in patients from group B. Individual parameters may characterize bone structure, which had undergone bone augmentation with xenogenic material. Finally, we showed that the properly selected multifractal quantificators obtained for those images could be used to assign those images to the appropriate group. ConclusionThe proposed analysis based on RVG images could help to evaluate the healing process after bone loss. The analysis and interpretation of the healing process after bone loss using monofractal and multifractal analysis as a multi-steps process quantify a stable (good) clinical result.

Long‐term culture of human pluripotent stem cells on coverslips coated with peptide‐poly(styrene‐co‐vinyl benzoic acid) copolymer

Human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs) have the potential to grow indefinitely (self‐renewal) in culture and differentiate into any cell type in adult human body. The hESCs and hiPSCs represent important resources for regenerative medicine and for disease modeling. Therefore, growing stem cells in undifferentiated state is important. The human pluripotent stem cells are expanded traditionally using either mitotically inactivated mouse embryonic fibroblasts (feeder cells) or Matrigel (MG). Both feeder cells and MG are prepared using mouse tissues that have several disadvantages. These manufactured expensive biological materials that have limited scalability also have high batch‐to‐batch variability. In addition, the animal‐derived (xenogenic) materials have potential to spread inter‐species pathogens. Thus, in order to replace these animal based biological materials, great efforts have been invested to develop synthetic materials that could be used for long‐term pluripotent stem cell growth and proliferation. As a consequence, materials such as poly [2‐(methacryloyloxy) ethyl dimethyl‐(3‐sulfopropyl) ammonium hydroxide] (PMEDSAH) and UV treated peptide‐acrylate materials have been used to culture hESCs. Since these synthetic materials are polymerized directly on the surface of cell culture dish, its application in broad sector and large‐scale expansion of stem cells for downstream applications has limitation. Thus, in the present study, we used a copolymer system containing poly (vinyl benzoic acid‐co‐styrene) (PVBA‐St), which could be coated onto various cell culture surfaces, such as glass, polystyrene cell culture plate etc. We synthesized PVBA‐St via nitroxide‐mediated polymerization to obtain polymer with narrow polydispersity index (PDI) and controlled molecular weight. In this study, we tested the stem cell growth on glass coverslips coated with peptide (extracellular matrix related) conjugated‐PVBA‐St. Up on initial screening, three active peptides were identified suitable for pluripotent stem cells expansion and self‐renewal. The long‐term culture of three pluripotent stem cell lines (H7, HUES‐7 and DF699) further confirmed the applicability and robustness of the copolymer system.Support or Funding InformationFunding was provided by the Institute of Bioengineering and Nanotechnology (Biomedical Research Council, Agency for Science, Technology and Research, Singapore). VMR was supported by funding from National Institutes of Health grant (NIH/NIDDK RO1DK104791)This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Improved Adipocyte Viability in Autologous Fat Grafting With Ascorbic Acid-Supplemented Tumescent Solution.

In reconstructive surgery, fat volume augmentation is often necessary for esthetic or functional reasons. As an alternative to synthetic and xenogeneic materials, autologous fat grafting (AFG) based on liposuction is gaining popularity, yet successful transplantation and long-term volume maintenance are difficult. Standard tumescent solution formulations neglect adipocyte and stromal vascular fraction (SVF) cell survival during extraction, as well as SVF differentiation into adipocytes thereafter, all of which are crucial for the success of AFG. Here we hypothesized that addition of ascorbic acid (AA) to the tumescent solution could prevent liposuction-induced cell damage. The effect of 0.1 mmol/L AA in tumescent solution was investigated in a previously described ex vivo model of AFG. Briefly, excision fat was infiltrated with tumescent solution, with or without AA, and incubated for 20 minutes at 37°C. Hand-assisted liposuction was then performed with a blunt cannula. Total cell viability, clonogenicity, and differentiation capacity of the SVF cells were assessed. With AA, 10.3% more cells and in particular 14.9% more adipocytes survived liposuction. Clonogenicity, adipocyte and osteoblast differentiation by SVF cells remained unchanged. Addition of AA successfully improved survival of adipocytes during liposuction without affecting SVF growth and differentiation. This study therefore identified a useful supplement to the tumescent solution which may lead to improving AFG success.

Development of xenogeneic decellularized biotubes for off-the-shelf applications.

In earlier studies, we developed in vivo tissue-engineered, autologous, small-caliber vascular grafts, called "biotubes," which withstand systemic blood pressure and exhibit excellent performance as small-caliber vascular prostheses in animal models. However, biotube preparation takes 4weeks; therefore, biotubes cannot be applied in emergency situations. Moreover, for responses to various types of surgery, grafts should ideally be readily available in advance. The aim of this study was to develop novel, off-the-shelf, small-caliber vascular grafts by decellularizing in vivo tissue-engineered xenogeneic tubular materials. Silicone rod molds (diameter: 2mm, length: 70mm) placed in subcutaneous pouches of a beagle dog for 4weeks were harvested with their surrounding connective tissues. Tubular connective tissues were obtained after pulling out the impregnated molds. Subsequently, they were decellularized by perfusion with sodium dodecyl sulfate and Triton X-100. They were stored as off-the-shelf grafts at -20°C for 1week. The decellularized grafts derived from the beagle dog were xenogeneically transplanted to the abdominal aortas of rats (n=3). No signs of abnormal inflammation or immunological problems due to the xenogeneic material were observed. Echocardiography confirmed the patency of the grafts at 1month after implantation. Histological evaluation revealed that the grafts formed neointima on the luminal surface, and that the graft walls had cell infiltration. Little accumulation of CD68-positive macrophages in the graft wall was observed. Xenogeneic decellularized tubular tissues functioned as small-caliber vascular grafts, as well as autologous biotubes. This technology enables the easy fabrication of grafts from xenogeneic animals in advance and their storage for at least a week, satisfying the conditions for off-the-shelf grafts.

Invited commentary

Mirza and colleagues present outcomes of upper extremity access (UEA) for complex aortic repair of thoracoabdominal aortic aneurysms (TAAAs).1Mirza A.K. Oderich G.S. Sandri G.A. Tenorio E.R. Davila V.J. Kärkkäinen J.M. et al.Outcomes of upper extremity access during fenestrated-branched endovascular aortic repair.J Vasc Surg. 2019; 69: 635-644Abstract Full Text Full Text PDF PubMed Scopus (36) Google Scholar To date, this is by far the largest retrospective study on the topic, and the authors are to be congratulated for their results and this important effort to cast some light on a frequently neglected topic. Except for a few reports, UEA for complex aortic repair has rarely been focused on and can be controversially discussed with a diversity of approaches.2Fiorucci B. Kölbel T. Rohlffs F. Heidemann F. Debus S.E. Tsilimparis N. Right brachial access is safe for branched endovascular aneurysm repair in complex aortic disease.J Vasc Surg. 2017; 66: 360-366Abstract Full Text Full Text PDF PubMed Scopus (38) Google Scholar, 3Knowles M. Nation D.A. Timaran D.E. Gomez L.F. Baig M.S. Valentine R.J. et al.Upper extremity access for fenestrated endovascular aortic aneurysm repair is not associated with increased morbidity.J Vasc Surg. 2015; 61: 80-87Abstract Full Text Full Text PDF PubMed Scopus (41) Google Scholar The complication rate for UEA in the presented large study from a center of excellence is exceptionally low. However, the majority are strokes, and real-world data would presumably show a significantly higher rate of serious neurologic complications. Operator-reported neurologic outcomes without examination by a neurologist and diffusion-weighted magnetic resonance imaging have a tendency to underestimate the issue. Therefore, reported outcomes, as the authors mention, do not take into account silent brain injury, which is a frequent magnetic resonance finding in thoracic endovascular aortic repair and a growing concern because of induced neurocognitive decline.4Perera A.H. Rudarakanchana N. Monzon L. Bicknell C.D. Modarai B. Kirmi O. et al.Cerebral embolization, silent cerebral infarction and neurocognitive decline after thoracic endovascular aortic repair.Br J Surg. 2018; 105: 366-378Crossref PubMed Scopus (39) Google Scholar The superb illustrations in the article provide excellent visualization of the authors' preferred repair technique for dissected brachial arteries using xenogenic material in one of eight patients with UEA. Whereas the additional time required for UEA closure and patch angioplasty may prolong some of the procedures, reduced catheterization times for the target vessels seem to justify the effort. The absence of secondary procedures needed is an impressive result supporting the group's strategy of open UEA and a low threshold for patch angioplasty. In a significant proportion of complex endovascular repairs, UEA is optional, namely, when solely fenestrations are used to connect target vessels to the main graft (fenestrated endovascular aneurysm repair). Fenestrations can be connected from femoral access, although UEA may provide advantages when target vessels are caudally oriented. Differences in utilization of UEA are mostly due to tradition and surgical teaching. Mirza et al now give us valid information at what cost this frequently used optional step comes in endovascular TAAA repair. For endografts with directional branches (branched endovascular aneurysm repair), such as the t-Branch (Cook Medical, Bloomington, Ind), UEA has been judged unavoidable, and discussions have focused on the preferred side of UEA.1Mirza A.K. Oderich G.S. Sandri G.A. Tenorio E.R. Davila V.J. Kärkkäinen J.M. et al.Outcomes of upper extremity access during fenestrated-branched endovascular aortic repair.J Vasc Surg. 2019; 69: 635-644Abstract Full Text Full Text PDF PubMed Scopus (36) Google Scholar, 2Fiorucci B. Kölbel T. Rohlffs F. Heidemann F. Debus S.E. Tsilimparis N. Right brachial access is safe for branched endovascular aneurysm repair in complex aortic disease.J Vasc Surg. 2017; 66: 360-366Abstract Full Text Full Text PDF PubMed Scopus (38) Google Scholar However, recent experience has demonstrated that with the use of steerable sheaths, even four-branched repairs in challenging anatomy of TAAA could be performed from femoral access alone (Fig). Whereas some operators prefer left-sided UEA with the argument of reduced manipulation in the aortic arch and assumed reduced stroke risk, other operators prefer right-sided UEA because of the assumed better workflow and lower radiation dose. The authors conclude that left-sided UEA is associated with a lower stroke rate in their study but acknowledge a significant selection bias and describe a trend in their practice toward right-sided UEA for better workflow and lower radiation dose. Convincing evidence about the better access side is still lacking, and the authors' conclusion should be taken with caution as data do not support a recommendation for left-sided access in general. Outcomes of upper extremity access during fenestrated-branched endovascular aortic repairJournal of Vascular SurgeryVol. 69Issue 3PreviewUpper extremity (UE) access is frequently used during fenestrated-branched endovascular aortic repair (F-BEVAR) to facilitate catheterization of downgoing vessels. Limitations include risk of cerebral embolization and of UE arterial or peripheral nerve injury. The aim of this study was to assess outcomes of F-BEVAR using UE access. Full-Text PDF Open Archive

Хирургическое лечение пациентов с хроническим перфоративным гайморитом с применением различных форм ксеногенного материала на основе коллагена

Хирургическое лечение пациентов с хроническим перфоративным гайморитом с применением различных форм ксеногенного материала на основе коллагена

Regenerative properties of human extraembryonal organs in tissue engineering

The characteristics of the umbilical cord extracellular matrix are discussed relatively of their potential use for tissue engineering. The purpose of this review is to assess the current knowledge about using of homologous biomaterials with regenerative properties to create bioengineered structures. One of the most important components of tissue engineering - matrix (scaffold), resident cells can migrate, attach to it and function. Due to their structure, matrices should be easily integrated into the patient’s tissue and provide conditions for cell growth and differentiation. The cells that populate the matrix in the bioreactor before the transplantation of this construction, or resident cells recruited into the transplanted extracellular matrix), and cell- matrix interactions are absolutely necessary components of tissue engineering. Available commercial bioengineering products made from mammalian tissues have certain advantages and significant disadvantages due to the risks of immunological reactions and transmission of infectious agents. The transplantation of products from xenogenic materials is prohibited by law in the Russian Federation. The donor material is limited, receipt of human cadaver material requires a long period of legal registration, which has a detrimental effect on the biomaterial. Therefore, finding a suitable homologous biomaterial is ongoing. Due to the peculiarities of the embryonic phenotype, extraembryonic tissues have special biological properties, one of which is the scarless healing of wounds. Low immunogenicity, optimal mechanical properties of extracellular matrix, presence of cell adhesion molecules and growth factors promoting regeneration provide anti-inflammatory, anti-fibrotic, anti- scarring properties for tissue engineering structures from umbilical cord and amniotic membrane. Umbilical cord and amnion due to the availability and non-invasiveness of obtaining from healthy young donors are an excellent source of homologous biomaterial for extracting matrices, cells and hydrogels for tissue engineering and regenerative medicine.