Long-term Repair Research Articles

Survival and Durability of Minimally Invasive Mitral Valve Repair: Insights from Different Repair Techniques.

This study evaluates the long-term outcomes of minimally invasive mitral valve repair (MIMVR) in patients with degenerative mitral regurgitation, focusing on survival, mitral valve repair failure, and re-operation rates. A cohort of patients undergoing three primary repair techniques-quadrangular resection, edge-to-edge repair, and artificial chordae implantation-was analyzed using time-to-event methods. The overall survival rates at 1, 10, and 20 years were high and comparable among the techniques, indicating effective long-term benefits of MIMVR. However, freedom from recurrence of moderate mitral regurgitation (MR) ≥ 2 was significantly higher in the quadrangular resection and edge-to-edge groups compared to the artificial chordae group. No significant differences were observed for recurrent MR ≥ 3. Re-operation rates were low and similar across all techniques, underscoring the durability of MIMVR. Pre-discharge residual MR ≥ 2 was identified as a strong predictor of long-term repair failure. These findings confirm the effectiveness of MIMVR, with all techniques demonstrating excellent long-term survival and durability.

A polyurea capturing both high strength and rapid self-healing tailored for intelligent barrier anti-corrosion system

The long-term repair of organic coatings in underwater environments is hindered by microcracks and their poor healing performance. In this study, a high-strength and rapidly self-healing polyurea (PU3) coating that combines asymmetric dense stacking of supramolecular units with mismatched rigid and flexible polymer chains was developed. By exploiting the interaction between a 2D sheet-like Ti3C2TX MXene and finely tailored hydrogen-bonded structures of PU3, a smart biomimetic anticorrosion composite coating (PU3-1.0 wt% MXene) was produced. This coating achieved rapid (15 s), specific, and repeatable in situ repair underwater when exposed to near infrared laser light. Electrochemical tests confirmed its excellent anticorrosion capability.

Mitral valve repair in ventricular functional mitral regurgitation: a simplified technique of papillary muscles relocation.

Mitral valve repair techniques in ventricular functional mitral regurgitation are controversial due to ongoing debates about long-term repair durability in the setting of left ventricular remodelling. To address the limitations of conventional annuloplasty, subannular techniques, such as papillary muscle relocation, have been developed. However, the limited reproducibility of these techniques has hindered their widespread adoption. In this context, we introduce a simplified and reproducible method for papillary muscle relocation. This method utilizes transoesophageal echocardiographic guidance and premeasured polytetrafluoroethylene loops to streamline the procedure.

Single dose of intravenous miR199a-5p delivery targeting ischemic heart for long-term repair of myocardial infarction

Long-term treatment of myocardial infarction is challenging despite medical advances. Tissue engineering shows promise for MI repair, but implantation complexity and uncertain outcomes pose obstacles. microRNAs regulate genes involved in apoptosis, angiogenesis, and myocardial contraction, making them valuable for long-term repair. In this study, we find downregulated miR-199a-5p expression in MI. Intramyocardial injection of miR-199a-5p into the infarcted region of male rats revealed its dual protective effects on the heart. Specifically, miR-199a-5p targets AGTR1, diminishing early oxidative damage post-myocardial infarction, and MARK4, which influences long-term myocardial contractility and enhances cardiac function. To deliver miR-199a-5p efficiently and specifically to ischemic myocardial tissue, we use CSTSMLKAC peptide to construct P-MSN/miR199a-5p nanoparticles. Intravenous administration of these nanoparticles reduces myocardial injury and protects cardiac function. Our findings demonstrate the effectiveness of P-MSN/miR199a-5p nanoparticles in repairing MI through enhanced contraction and anti-apoptosis. miR199a-5p holds significant therapeutic potential for long-term repair of myocardial infarction.

Pengelolaan Sarana Dan Prasarana di Sekolah Madrasah Aliyah Laboratorium UINSU

This research examines the management of facilities and infrastructure at the Madrasah Aliyah Laboratory of UIN North Sumatra (UIN SU) using quantitative and qualitative approaches. The aim of the research is to identify the main obstacles in facility management and provide strategic recommendations for improvement. Through a quantitative survey, it was found that there were significant differences in perceptions between teachers and students regarding the condition of school facilities, with teachers tending to be more critical. Further analysis shows that planned and routine maintenance plays an important role in preventing further damage and reducing long-term repair costs. In addition, the level of student satisfaction with facilities and infrastructure varies by grade level, with students in higher grades showing lower levels of satisfaction. A qualitative approach through in-depth interviews revealed that budget constraints were the main obstacle in facility management. Based on these findings, several strategic recommendations were proposed, including increasing budgets and resources through collaboration with external parties, implementing continuous training programs for teachers and staff, improving communication with parents, and implementing information technology in facility management. It is hoped that the implementation of these recommendations can improve the quality of management of facilities and infrastructure, which will ultimately have a positive impact on the quality of education in this madrasa. This research makes an important contribution to the education management literature, especially in the context of madrasas in Indonesia, and becomes a reference for future research and practice.

Current challenges in imaging the mechanical properties of tissue engineered grafts

The mechanical performance of tissue-engineered grafts is crucial in determining their functional properties, integration with native tissue and long-term repair outcome post-implantation. To date, most approaches for testing the mechanical properties of tissue-engineered grafts are non-sterile and invasive. There is an urgent need to develop novel sterile approaches for online monitoring mechanical properties of engineered tissues in order to ensure these engineered products meet the desired mechanical strength prior to implantation. In this paper, we overview various approaches for mechanical testing of engineered tissues, which span from traditional methods to medical imaging concepts in magnetic resonance elastography, ultrasound elastography, and optical coherence elastography. We focused on the applicability of these methods to the manufacturing of tissue-engineered products online, e.g., if such approach provides a sterile monitoring capacity and is capable of defining mechanical heterogeneity in engineered tissues throughout their growth in vitro in real-time. The review delves into various imaging modalities that employ distinct methods for inducing displacement within the sample, utilizing either strain-based or shear wave-based approaches. This displacement can be achieved through external stimulation or by harnessing ambient vibrations. Subsequently, the imaging process captures and visualizes the resultant displacement. We specifically highlight the advantages of novel non-invasive imaging methods such as ultrasound elastography and optical coherence elastography to assess the mechanical properties of engineered tissues in vitro, as well as their potential applications in cancer study, drug screening and the in vivo evaluation of the engineered tissues.

3D-printed biodegradable polycaprolactone rib implants with tissue-specific mechanical properties promote chest wall recovery by stimulating tissue fibrosis

ABSTRACT Here we developed a tripartite biodegradable rib implant with tissue-specific mechanical properties by employing polycaprolactone and a dual-structure-reinforced selective laser sintering (SLS) strategy. Computational simulation revealed that the tripartite rib implant, with a 9 mm diameter load-bearing structure, exhibited a rib-like three-point bending stiffness of 31.3 N/mm, can withstand a maximum force of 121.5 N, and restore similar respiration movements of natural ribs. The modified SLS enabled the fabrication of the as-designed rib implants with improved mechanical properties while maintaining structural fidelity compared to conventional SLS, and their mechanical properties were validated through three-point bending, impact, and flexural fatigue testing. The 3D-printed biodegradable tripartite rib implant effectively prevented abnormal breathing and significantly improved the chest wall's morphological and physiological functions in a large-scale canine rib defect model. This exploration provides a promising approach to engineer biodegradable rib implants with tissue-specific mechanical properties for the long-term repair of chest wall defects.

Antibiotic administration aggravates asthma by disrupting gut microbiota and the intestinal mucosal barrier in an asthma mouse model.

In humans, gut microbiota can determine the health status. The regulatory mechanisms of the gut microbiota in asthma must be elucidated. Although antibiotics (ABXs) can clear infections, they markedly alter the composition and abundance of gut microbiota. The present study used ABX-treated mice to examine the time-dependent effects of ABX administration on the gut microbiota and intestinal mucosal barrier. The mouse asthma model was established using ovalbumin (OVA) and gavaged with an ABX cocktail for different durations (1 or 2 weeks) and stacked sequences. The pathology of the model, model 2, OVA-ABX, OVA-ABX 2, ABX-OVA and ABX-OVA was severe when compared with the control group as evidenced by the following results: i) significantly increased pulmonary and colonic inflammatory cell infiltration; ii) enhanced pause values and iii) OVA-induced immunoglobulin E (IgE) and TGF-β expression levels, and significantly downregulated Tight Junction Protein 1 (TJP1), claudin 1 and Occludin expression levels. Furthermore, the intestinal bacterial load in the OVA-ABX and OVA-ABX 2 groups was significantly lower than that in the ABX-OVA and ABX-OVA 2 groups, respectively. The predominant taxa were as follows: phyla, Firmicutes and Proteobacteria, genera, Escherichia-Shigella, Lactobacillus and Lachnospira. The abundances of Lachnospira and Escherichia-Shigella were correlated with the expression of OVA-induced IgE and TJPs. These findings indicated that ABX administration, which modifies microbiome diversity and bacterial abundance, can disrupt colonic integrity, downregulate TJ proteins, damage the intestinal barrier, enhance enterocyte permeability, and promote the release of inflammatory factors, adversely affecting asthma alleviation and long-term repair.

Sevoflurane Postconditioning Protects From an Early Neurological Deficit After Subarachnoid Hemorrhage: Results of a Randomized Laboratory Study in Rats.

Subarachnoid hemorrhage (SAH) is associated with neurocognitive impairment. Recent data suggest that sevoflurane attenuates edema formation after SAH in rats. However, so far, no information is available about the long-term repair phase, nor if sevoflurane impacts functionality by increasing vascularity. This study tested whether sevoflurane postconditioning would improve long-term neurologic deficit through increased formation of new vessels close to the hemorrhage area. Fifty-three animals were subjected to SAH or sham surgery with or without a 2-hour sevoflurane postconditioning (versus propofol anesthesia). Animal survival, including dropout animals due to death or reaching termination criteria, as well as neurologic deficit, defined by the Garcia score, were assessed 2 hours after recovery until postoperative day 14. On day 14, blood samples and brain tissue were harvested. Vessel density was determined by the number of cluster of differentiation 31 (CD31)-positive vessels, and activated glial cells by glial fibrillary acidic protein (GFAP)-positive astrocytes per field of view. The survival rate for sham animals was 100%, 69% in the SAH-propofol and 92% in the SAH-sevoflurane groups. According to the log-rank Mantel-Cox test, survival curves were significantly different ( P = .024). The short-term neurologic deficit was higher in SAH-propofol versus SAH-sevoflurane animals 2 hours after recovery and on postoperative day 1 (propofol versus sevoflurane: 14. 6 ± 3.4 vs 15. 9 ± 2.7 points, P = .034, and 16. 2 ± 3.5 vs 17. 8 ± 0.9 points, P = .015). Overall complete recovery from neurologic deficit was observed on day 7 in both SAH groups (18. 0 ± 0.0 vs 18. 0 ± 0.0 points, P = 1.000). Cortical vascular density increased to 80. 6 ± 15.0 vessels per field of view in SAH-propofol animals (vs 71. 4 ± 10.1 in SAH-sevoflurane, P < .001). Activation of glial cells, an indicator of neuroinflammation, was assessed by GFAP-positive astrocytes GFAP per field of view. Hippocampal GFAP-positive cells were 201 ± 68 vs 179 ± 84 cells per field of view in SAH-propofol versus SAH-sevoflurane animals ( P < .001). Sevoflurane postconditioning improves survival by 23% (SAH-sevoflurane versus SAH-propofol). The sevoflurane intervention could attenuate the early neurologic deficit, while the long-term outcome was similar across the groups. A higher vascular density close to the SAH area in the propofol group was not associated with improved outcomes.

Revision Transtibial Medial Meniscal Root Repair With Concomitant Medial Opening-Wedge Proximal Tibial Osteotomy

Background: Complete meniscal root tears disrupt dispersion of axial loading forces through hoop stresses. This increases point-loading on tibiofemoral cartilage and leads to chondromalacia and accelerated osteoarthritis (OA). Posterior root tears may be treated successfully with a transtibial pullout repair. Varus malalignment also leads to increased medial compartment pressures, increasing the risk of early OA and putting increased stress on the meniscus and stabilizing knee ligaments. In particular, revision medial meniscal root repairs without correction of varus malalignment are at increased risk of failure. Genu varum may be corrected with a medial opening-wedge proximal tibial osteotomy (OW PTO). Indications: Meniscal root repairs are indicated for acute or chronic tears in active patients with healthy cartilage. OW PTO is indicated for varus malalignment in ambulatory patients with healthy cartilage, or who are at risk for failure of meniscal or ligamentous procedures. Technique Description: After exposure of the osteotomy site, arthroscopy is performed through the incision and the revision posterior meniscus root repair is performed via a double-tunnel transtibial pullout technique. The positioning of these tunnels is modified superiorly so as to not cross the planned osteotomy site. The osteotomy is then performed by drilling 2 guide pins under fluoroscopy to delineate the plane of the cut. An OW plate is placed, and the root repair is tensioned last. Results: Double-tunnel transtibial pullout repairs increase meniscal fixation contact surface and have been shown to be biomechanically superior to all-inside fixation techniques. Medial OW PTO restores knee alignment and reduces supra-anatomic stresses in the medial compartment, additionally decreasing the risk of a revision medial meniscus repair failure. Discussion: Biomechanical studies have shown that meniscal root tears are functionally equivalent to complete meniscectomy. Varus malalignment increases the risk of medial meniscal tears, and reduces the risk of a successful long-term repair. We describe a technique for a revision transosseous posterior root repair with concomitant proximal tibial osteotomy, with discussion of surgical pearls and pitfalls. This technique restores anatomic position and native function of the medial meniscus while correcting tibiofemoral malalignment that could jeopardize the repair. Patient Consent Disclosure Statement: The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form.

Novel Osteochondral Biotemplate Improves Long-term Cartilage Repair Compared With Microfracture in an Ovine Model

Background: Current cartilage repair therapies do not re-create the complex mechanical interface between cartilage and bone, which is critical for long-term repair durability. New biomaterial designs that include hard tissue–soft tissue interface structures offer promise to improve clinical outcomes. Purpose/Hypothesis: The purpose of this study was to evaluate the efficacy and safety of a naturally derived osteochondral biotemplate with a novel contiguous hard tissue–soft tissue interface in an ovine model as a regenerative solution for articular cartilage defects. It was hypothesized that the osteochondral biotemplate would produce structurally superior repair tissue compared with microfracture over a 13-month period. Study Design: Controlled laboratory study. Methods: Osteochondral biotemplates were manufactured from porcine cancellous bone. Skeletally mature sheep (N = 30) were randomly allocated to 3 groups: early healing stage (euthanasia at 4 months), 6-month treatment, and 13-month treatment. In the early healing stage group, an 8 mm–diameter by 5 mm–deep osteochondral defect was created on the medial femoral condyle and treated at the time of iatrogenic injury with an osteochondral biotemplate. The contralateral limb received the same treatment 2 months later. In the 6- and 13-month treatment groups, 1 limb received the same osteochondral procedure as the early healing stage group. In the contralateral limb, an 8 mm–diameter, full-thickness cartilage defect (1-2 mm deep) was created and treated with microfracture. Cartilage repair and integration were quantitatively and qualitatively assessed with gross inspection, histological evaluation, and magnetic resonance imaging (MRI). Wilcoxon signed-rank and McNemar tests were used to compare the treatments. Results: At 6 and 13 months after treatment, the biotemplate was not present histologically. At 13 months, the biotemplate treatment demonstrated statistically higher histological scores than microfracture for integration with surrounding cartilage (biotemplate: 74 ± 31; microfracture: 28 ± 39; P = .03), type 2 collagen (biotemplate: 72 ± 33; microfracture: 40 ± 38; P = .02), total cartilage (biotemplate: 71 ± 9; microfracture: 59 ± 9; P = .01), and total integration (biotemplate: 85 ± 15; microfracture: 66 ± 20; P = .04). The osteochondral biotemplate treatment produced a notable transient nonneutrophilic inflammatory response that appeared to approach resolution at 13 months. MRI results were not statistically different between the 2 treatments. Conclusion: Even with the inflammatory response, after 13 months, the osteochondral biotemplate outperformed microfracture in cartilage regeneration and demonstrated superiority in integration between the repair tissue and host tissue as well as integration between the newly formed cartilage and the underlying bone. Clinical Relevance: This work has demonstrated the clinical potential of a novel biomaterial template to regenerate the complex mechanical interface between cartilage and the subchondral bone.

Life Cycle Cost Method for Safe and Effective Infrastructure Asset Management

Existing maintenance management systems implement periodic inspections and diagnoses and perform maintenance to restore damaged facilities, making it difficult to establish a long-term and analytical budget plan. The Framework Act on Sustainable Infrastructure Management necessitates specific implementation plans for new implementation items. This study proposes a detailed method for estimating infrastructure management cost to overcome the limitations of the post-response maintenance system and establish a management plan for the Framework Act on Sustainable Infrastructure Management, considering the performance and cost effects in terms of the life cycle. The method was classified into the following stages: analysis of the performance degradation timing by deriving the performance degradation curve, analysis of proper construction methods by performance grade to establish a cost model for each member grade, representative life assessment of the establishment to determine the end-of-life of members, and analysis of optimal action timing for establishing short/mid- to long-term repair and reinforcement plans. The proposed method was applied to a water reservoir (99 reservoirs in Seoul, Korea). The performance degradation and cost prediction models for the target establishment were analyzed. The proposed method can be applied to the maintenance decision making of the management agency and is significant for efficient infrastructure maintenance.

Dual human iPSC-derived cardiac lineage cell-seeding extracellular matrix patches promote regeneration and long-term repair of infarcted hearts

Human pluripotent stem cell-derived cardiovascular progenitor cells (hCVPCs) and cardiomyocytes (hCMs) possess therapeutic potential for infarcted hearts; however, their efficacy needs to be enhanced. Here we tested the hypotheses that the combination of decellularized porcine small intestinal submucosal extracellular matrix (SIS-ECM) with hCVPCs, hCMs, or dual of them (Mix, 1:1) could provide better therapeutic effects than the SIS alone, and dual hCVPCs with hCMs would exert synergic effects in cardiac repair. The data showed that the SIS patch well supported the growth of hCVPCs and hCMs. Epicardially implanted SIS-hCVPC, SIS-hCM, or SIS-Mix patches at 7-day post-myocardial infarction significantly ameliorated functional worsening, ventricular dilation and scar formation at 28- and 90-day post-implantation in C57/B6 mice, whereas the SIS only mildly improved function at 90-day post-implantation. Moreover, the SIS and SIS-cell patches improved vascularization and suppressed MI-induced cardiomyocyte hypertrophy and expression of Col1 and Col3, but only the SIS-hCM and the SIS-Mix patches increased the ratio of collagen III/I fibers in the infarcted hearts. Further, the SIS-cell patches stimulated cardiomyocyte proliferation via paracrine action. Notably, the SIS-Mix had better improvements in cardiac function and structure, engraftments, and cardiomyocyte proliferation. Proteomic analysis showed distinct biological functions of exclusive proteins secreted from hCVPCs and hCMs, and more exclusive proteins secreted from co-cultivated hCVPCs and hCMs than mono-cells involving in various functional processes essential for infarct repair. These findings are the first to demonstrate the efficacy and mechanisms of mono- and dual-hCVPC- and hCM-seeding SIS-ECM for repair of infarcted hearts based on the side-by-side comparison.

Structural and biological investigation of alginate-nano-hydroxyapatite with chitosan-hyaluronic acid for potential osteochondral regeneration

Cartilage joint lesions have created a significant challenge in the field of durable reconstruction and recovery due to their limited long-term repair and reconstruction. In this study, a biphasic scaffold was obtained using chitosan (CS)-hyaluronic acid (HA) and alginate-nanohydroxyapatite (nHAP) for osteoarthritis diseases. The scaffolds revealed porous structures and hydrophilic chemical groups by scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR) methods, respectively. The resulting three-dimensional hydrogels were assembled by using fibrin glue and seeded with human chondrocytes cells (hCHCs) in the chondral layer and human adipose-derived mesenchymal stem cells (hAdMSCs) in the subchondral one. Then, the assessments including 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT), SEM, compressive assay, weight loss, alizarin red staining, alkaline phosphatase (ALP) activity, alcian blue staining and Real-Time PCR were performed. The associated cell viability confirmed that there were no interventions between the cell types and SEM illustrated cell attachment and spreading. The subchondral and chondral layers were investigated separately to detect their ability for cellular commitment. Finally, the Real-time PCR was carried out on the bilayer scaffold and the related observations approved the osteogenic/chondrogenic differentiation of both cell types. Taken together, the Alg-nHAP/CS-HA scaffold provided an appropriate environment for cartilage and bone regenerations and could be recommended for all aspects of osteochondral tissue engineering.

Chordal force profile after neochordal repair of anterior mitral valve prolapse: An ex vivo study

ObjectiveThis study aimed to biomechanically evaluate the force profiles on the anterior primary and secondary chordae after neochord repair for anterior valve prolapse with varied degrees of residual mitral regurgitation using an ex vivo heart simulator. MethodsThe experiment used 8 healthy porcine mitral valves. Chordal forces were measured using fiber Bragg grating sensors on primary and secondary chordae from A2 segments. The anterior valve prolapse model was generated by excising 2 primary chordae at the A2 segment. Neochord repair was performed with 2 pairs of neochords. Varying neochord lengths simulated postrepair residual mitral regurgitation with regurgitant fraction at >30% (moderate), 10% to 30% (mild), and <10% (perfect repair). ResultsRegurgitant fractions of baseline, moderate, mild, and perfect repair were 4.7% ± 0.8%, 35.8% ± 2.1%, 19.8% ± 2.0%, and 6.0% ± 0.7%, respectively (P < .001). Moderate had a greater peak force of the anterior primary chordae (0.43 ± 0.06 N) than those of baseline (0.19 ± 0.04 N; P = .011), mild (0.23 ± 0.05 N; P = .041), and perfect repair (0.21 ± 0.03 N; P = .006). In addition, moderate had a greater peak force of the anterior secondary chordae (1.67 ± 0.17 N) than those of baseline (0.64 ± 0.13 N; P = .003), mild (0.84 ± 0.24 N; P = .019), and perfect repair (0.68 ± 0.14 N; P = .001). No significant differences in peak and average forces on both primary and secondary anterior chordae were observed between the baseline and perfect repair as well as the mild and perfect repair. ConclusionsModerate residual mitral regurgitation after neochord repair was associated with increased anterior primary and secondary chordae forces in our ex vivo anterior valve prolapse model. This difference in chordal force profile may influence long-term repair durability, providing biomechanical evidence in support of obtaining minimal regurgitation when repairing mitral anterior valve prolapse.

Research progress of histone acetylation in prevention and treatment of heart failure and new ideas based on traditional Chinese medicine

Chronic heart failure(CHF) has become a worldwide public health problem due to its high morbidity and mortality, which seriously endangers people's lifespan and quality of life. In recent years, the treatment strategy of CHF has shifted its emphasis on short-term improvement and transformation of hemodynamics to long-term repair as well as improvement of the biological properties of heart failure. At present, with the continuous deepening of medical research, it has been found that histone acetylation is closely related to the occurrence and development of CHF. Traditional Chinese medicine, via regulating histone acetylation, delays ventricular remodeling, improves energy metabolism, inhibits fibrosis and cardiomyocyte hypertrophy, and intervenes in the development process of heart failure, thus reducing the mortality and the readmission rate and ultimately improving long-term prognosis. Therefore, this study reviewed the mechanism of histone acetylation in the treatment of heart failure as well as its prevention and treatment with traditional Chinese medicine, to provide reference for clinical treatment of CHF.

Effect of ascending aorta replacement on the long-term outcomes of bicuspid aortic valve repair

ObjectiveThe study objective was to determine the effect of sinutubular junction stabilization on long-term outcomes of bicuspid aortic valve repair. MethodsFrom January 1998 to January 2020, 419 patients underwent bicuspid aortic valve repair with ascending aorta replacement and 421 without (bicuspid aortic valve repair alone). Propensity score matching (97 pairs) was used to compare outcomes. ResultsBefore matching, prevalence of severe aortic regurgitation at 10 years was 5.4% after bicuspid aortic valve repair + ascending aorta replacement and 10% after bicuspid aortic valve repair alone; aortic valve gradient was 20 mm Hg after bicuspid aortic valve repair + ascending aorta replacement and 19 mm Hg after bicuspid aortic valve repair alone. Ten-year freedom from reoperation overall was 79% after bicuspid aortic valve repair + ascending aorta replacement and 75% after bicuspid aortic valve repair alone; freedom from late aortic regurgitation was 93% after bicuspid aortic valve repair + ascending aorta replacement and 92% after bicuspid aortic valve repair alone; and freedom from aortic stenosis was 87% after bicuspid aortic valve repair + ascending aorta replacement and 93% after bicuspid aortic valve repair alone. Ten-year survival was 95% after bicuspid aortic valve repair + ascending aorta replacement and 96% after bicuspid aortic valve repair alone. After matching, prevalence of severe aortic regurgitation at 10 years was 11% after bicuspid aortic valve repair + ascending aorta replacement and 9.1% after bicuspid aortic valve repair alone (P = .33); aortic valve gradient was 16 mm Hg after bicuspid aortic valve repair + ascending aorta replacement and 25 mm Hg after bicuspid aortic valve repair alone (P < .0001). Ten-year freedom from reoperation was 85% after bicuspid aortic valve repair + ascending aorta replacement and 72% after bicuspid aortic valve repair alone (P = .08) overall. Ten-year freedom from reoperation for late aortic regurgitation was 88% after bicuspid aortic valve repair + ascending aorta replacement and 86% after bicuspid aortic valve repair alone (P = .65). Freedom from aortic stenosis was 97% after bicuspid aortic valve repair + ascending aorta replacement and 91% after bicuspid aortic valve repair alone (P = .03). Ten-year survival was 96% after bicuspid aortic valve repair + ascending aorta replacement and 96% after bicuspid aortic valve repair alone (P = .16). ConclusionsBicuspid aortic valve repair with or without ascending aorta replacement is associated with good short- and long-term outcomes. Bicuspid aortic valve repair + ascending aorta replacement has a minimal effect on long-term repair durability. Sinutubular junction stabilization should not be performed for the sole purpose of long-term repair durability.

Development of a Long-Term Repair Allowance Estimation Model for Apartments Based on Multiple Regression Analysis in Korea

Buildings aged 20 years or older account for 63.34% of all edifices in Korea. To ensure sustainable construction, apartment managers must plan and allocate financial resources to maintain communal facilities. However, on the one hand, long-term repair allowances (LTRAs) can be underestimated relative to actual repair costs; consequently, apartments can rapidly deteriorate. On the other hand, the long-term allowance may exceed the actual repair expenditure, thus, wasting resources. Existing estimation methods do not consider the apartment management degree, equipment condition, time value, or the extent of building deterioration. Based on multiple regression, this study developed a repair budget estimation model that considers the influencing factors that include the main characteristics of apartments and the time value, thereby allowing apartment managers to estimate the appropriate long-term repair expenses. In the conducted experiments, the root mean square and mean absolute percentage errors of the estimation model were USD 144,587.38 and 25.6%, respectively. Further, ANOVA results showed a difference between the actual and estimated total long-term repair costs. The resulting model should support apartment managers in establishing reliable maintenance budgets and effectively prevent the functional degradation of buildings.

Engineered extracellular vesicles for ischemic stroke treatment

Engineered extracellular vesicles for ischemic stroke treatment

Bioprinted anisotropic scaffolds with fast stress relaxation bioink for engineering 3D skeletal muscle and repairing volumetric muscle loss.

Viscoelastic hydrogels can enhance 3D cell migration and proliferation due to the faster stress relaxation promoting the arrangement of the cellular microenvironment. However, most synthetic photocurable hydrogels used as bioink materials for 3D bioprinting are typically elastic. Developing a photocurable hydrogel bioink with fast stress relaxation would be beneficial for 3D bioprinting engineered 3D skeletal muscles in vitro and repairing volumetric muscle loss (VML) in vivo; however, this remains an ongoing challenge. This study aims to develop an interpenetrating network (IPN) hydrogel with tunable stress relaxation using a combination of gelatin methacryloyl (GelMA) and fibrinogen. These IPN hydrogels with faster stress relaxation showed higher 3D cellular proliferation and better differentiation. A 3D anisotropic biomimetic scaffold was further developed via a printing gel-in-gel strategy, where the extrusion printing of cell-laden viscoelastic FG hydrogel within Carbopol supported gel. The 3D engineered skeletal muscle tissue was further developed via 3D aligned myotube formation and contraction. Furthermore, the cell-free 3D printed scaffold was implanted into a rat VML model, and both the short and long-term repair results demonstrated its ability to enhance functional skeletal muscle tissue regeneration. These data suggest that such viscoelastic hydrogel provided a suitable 3D microenvironment for enhancing 3D myogenic differentiation, and the 3D bioprinted anisotropic structure provided a 3D macroenvironment for myotube organization, which indicated the potential in skeletal muscle engineering and VML regeneration. STATEMENT OF SIGNIFICANCE: The development of a viscoelastic 3D aligned biomimetic skeletal muscle scaffold has been focused on skeletal muscle regeneration. However, a credible technique combining viscoelastic hydrogel and printing gel-in-gel strategy for fabricating skeletal muscle tissue was rarely reported. Therefore, in this study, we present an interpenetrating network (IPN) hydrogel with fast stress relaxation for 3D bioprinting engineered skeletal muscle via a printing gel-in-gel strategy. Such IPN hydrogels with tunable fast stress relaxation resulted in high 3D cellular proliferation and adequate differentiation in vitro. Besides, the 3D hydrogel-based scaffolds also enhance functional skeletal muscle regeneration in situ. We believe that this study provides several notable advances in tissue engineering that can be potentially used for skeletal muscle injury treatment in clinical.