ABSTRACT
BACKGROUND: The performance of latest iteration transcatheter aortic valve replacement platforms in patients with small aortic anatomy remains underexplored. OBJECTIVES: The aim of this study was to evaluate effectiveness and performance between the self-expanding (SE) Evolut PRO and PRO+ and the balloon-expandable (BE) SAPIEN ULTRA in patients with small aortic annuli. METHODS: Data from the OPERA-TAVI (Comparative Analysis of Evolut PRO vs. SAPIEN 3 ULTRA Valves for Transfemoral Transcatheter Aortic Valve Implantation) registry were used, with 1:1 propensity score matching. Primary endpoints included 1-year effectiveness composite (all-cause mortality, disabling stroke, or heart failure hospitalization) and 30-day device-related (hemodynamic structural valve dysfunction and nonstructural valve dysfunction) outcomes. RESULTS: Among 3,516 patients, 251 matched pairs with aortic annular area <430 mm2 were assessed. The 1-year primary effectiveness outcome did not differ significantly between cohorts (SE 10.8% vs BE 11.2%; P = 0.91). The 30-day device-oriented composite outcome was more favorable in the Evolut PRO group (SE 4.8% vs BE 10.4%; P = 0.027). Notably, SE valve recipients showed higher rates of disabling stroke (SE 4.0% vs BE 0.0%; P < 0.01) and paravalvular leaks (mild or greater: SE 48.5% vs BE 18.6% [P < 0.001]; moderate: SE 4.5% vs BE 1.2% [P = 0.070]). The BE group had higher rates of prosthesis-patient mismatch (moderate or greater: SE 16.0% vs BE 47.1% [P < 0.001]; severe: SE 1.3% vs BE 5.7% [P = 0.197]) and more patients with residual mean gradients >20 mm Hg (SE 1.0% vs BE 13.5%; P < 0.001). CONCLUSIONS: In patients with small aortic annuli, transcatheter aortic valve replacement with latest iteration devices is safe. SE platforms are associated with more favorable device performance in terms of hemodynamic structural and nonstructural dysfunction. Randomized data are needed to validate these findings and guide informed device selection.
Subject(s)
Aortic Valve Stenosis , Heart Valve Prosthesis , Stroke , Transcatheter Aortic Valve Replacement , Humans , Aortic Valve/diagnostic imaging , Aortic Valve/surgery , Aortic Valve Stenosis/diagnostic imaging , Aortic Valve Stenosis/surgery , Prosthesis Design , Treatment Outcome , Registries , Stroke/etiologyABSTRACT
Evidence regarding gender-related differences in response to transcatheter aortic valve implantation according to the valve type is lacking. This study aimed to evaluate the impact of gender on the treatment effect of Evolut PRO/PRO+ (PRO) or SAPIEN 3 Ultra (ULTRA) devices on clinical outcomes. The Comparative Analysis of Evolut PRO vs SAPIEN 3 Ultra Valves for Transfemoral Transcatheter Aortic Valve Implantation (OPERA-TAVI) is a multicenter, multinational registry including patients who underwent the latest-iteration PRO or ULTRA implantation. Overall, 1,174 of 1,897 patients were matched based on valve type and compared according to gender, whereas 470 men and 630 women were matched and compared according to valve type. The 30-day and 1-year outcomes were evaluated. In the PRO and ULTRA groups, men had a higher co-morbidity burden, whereas women had smaller aortic root. The 30-day (device success [DS], early safety outcome, permanent pacemaker implantation, patient-prosthesis mismatch, paravalvular regurgitation, bleedings, vascular complications, and all-cause death) and 1-year outcomes (all-cause death, stroke, and heart failure hospitalization) did not differ according to gender in both valve groups. However, the male gender decreased the likelihood of 30-day DS with ULTRA versus PRO (p for interaction = 0.047). A higher risk of 30-day permanent pacemaker implantation and 1-year stroke and a lower risk of patient-prosthesis mismatch was observed in PRO versus ULTRA, regardless of gender. In conclusion, gender did not modify the treatment effect of PRO versus ULTRA on clinical outcomes, except for 30-day DS, which was decreased in men (vs women) who received ULTRA (vs PRO).
Subject(s)
Aortic Valve Stenosis , Heart Valve Prosthesis , Prosthesis Design , Registries , Transcatheter Aortic Valve Replacement , Humans , Transcatheter Aortic Valve Replacement/methods , Male , Female , Aortic Valve Stenosis/surgery , Sex Factors , Aged, 80 and over , Aged , Treatment Outcome , Postoperative Complications/epidemiology , Aortic Valve/surgeryABSTRACT
BACKGROUND: Midterm comparative analyses of the latest iterations of the most used Evolut and SAPIEN platforms for transcatheter aortic valve implantation (TAVI) are lacking. AIMS: We aimed to compare 1-year clinical outcomes of TAVI patients receiving Evolut PRO/PRO+ (PRO) or SAPIEN 3 Ultra (ULTRA) devices in current real-world practice. METHODS: Among patients enrolled in the OPERA-TAVI registry, patients with complete 1-year follow-up were considered for the purpose of this analysis. One-to-one propensity score matching was used to compare TAVI patients receiving PRO or ULTRA devices. The primary endpoint was a composite of 1-year all-cause death, disabling stroke and rehospitalisation for heart failure. Five prespecified subgroups of patients were considered according to leaflet and left ventricular outflow tract calcifications, annulus dimensions and angulation, and leaflet morphology. RESULTS: Among a total of 1,897 patients, 587 matched pairs of patients with similar clinical and anatomical characteristics were compared. The primary composite endpoint did not differ between patients receiving PRO or ULTRA devices (Kaplan-Meier [KM] estimates 14.0% vs 11.9%; log-rank p=0.27). Patients receiving PRO devices had higher rates of 1-year disabling stroke (KM estimates 2.6% vs 0.4%; log-rank p=0.001), predominantly occurring within 30 days after TAVI (1.4% vs 0.0%; p=0.004). Outcomes were consistent across all the prespecified subsets of anatomical scenarios (all pinteraction>0.10). CONCLUSIONS: One-year clinical outcomes of patients undergoing transfemoral TAVI and receiving PRO or ULTRA devices in the current clinical practice were similar, but PRO patients had higher rates of disabling stroke. Outcomes did not differ across the different anatomical subsets of the aortic root.
Subject(s)
Aortic Valve Stenosis , Heart Valve Prosthesis , Stroke , Transcatheter Aortic Valve Replacement , Humans , Transcatheter Aortic Valve Replacement/adverse effects , Aortic Valve/diagnostic imaging , Aortic Valve/surgery , Aortic Valve Stenosis/surgery , Heart Valve Prosthesis/adverse effects , Treatment Outcome , Registries , Stroke/etiology , Prosthesis DesignABSTRACT
BACKGROUND: Transcatheter aortic valve implantation (TAVI) is a minimally invasive procedure used to treat patients with severe aortic valve stenosis. However, there is limited knowledge on the material properties of the aortic root in TAVI patients, and this can impact the credibility of computer simulations. This study aimed to develop a non-invasive inverse approach for estimating reliable material constituents for the aortic root and calcified valve leaflets in patients undergoing TAVI. METHODS: The identification of material parameters is based on the simultaneous minimization of two cost functions, which define the difference between model predictions and cardiac-gated CT measurements of the aortic wall and valve orifice area. Validation of the inverse analysis output was performed comparing the numerical predictions with actual CT shapes and post-TAVI measures of implanted device diameter. RESULTS: A good agreement of the peak systolic shape of the aortic wall was found between simulations and imaging, with similarity index in the range in the range of 83.7% to 91.5% for n.20 patients. Not any statistical difference was observed between predictions and CT measures of orifice area for the stenotic aortic valve. After TAVI simulations, the measurements of SAPIEN 3 Ultra (S3) device diameter were in agreement with those from post-TAVI angio-CT imaging. A sensitivity analysis demonstrated a modest impact on the S3 diameters when altering the elastic material property of the aortic wall in the range of inverse analysis solution. CONCLUSIONS: Overall, this study demonstrates the feasibility and potential benefits of using non-invasive imaging techniques and computational modeling to estimate material properties in patients undergoing TAVI.
Subject(s)
Aortic Valve Stenosis , Heart Valve Prosthesis , Transcatheter Aortic Valve Replacement , Humans , Aortic Valve/diagnostic imaging , Aortic Valve/surgery , Aorta, Thoracic , Aortic Valve Stenosis/diagnostic imaging , Aortic Valve Stenosis/surgery , Tomography, X-Ray Computed , Treatment OutcomeABSTRACT
Transcatheter aortic valve replacement (TAVR) is increasingly being considered for use in younger patients having longer life expectancy than those who were initially treated. The TAVR-in-TAVR procedure represents an appealing strategy to treat failed transcatheter heart valves (THV) likely occurring in young patients. However, the permanent displacement of first THV can potentially compromise the coronary access and ultimately inhibit the blood flow circulation. The objective of this study was to use finite-element analysis (FEA) to quantify coronary flow in a patient who underwent TAVR-in-TAVR. A parametric investigation was carried out to determine the impact of both the implantation depth and device size on coronary flow for several deployment configurations. The FEAs consisted of first delivering the SAPIEN 3 Ultra THV and then positioning the Evolut PRO device. Findings indicates that high implantation depth and device undersize of the second THV could significantly reduce coronary flow to 20% of its estimated level before TAVR. Additionally, a positive correlation was observed between coronary flow and the valve-to-coronary distance (R = 0.86 and p = 0.032 for the left coronary artery, and R = 0.93 and p = 0.014 for the right coronary artery). This study demonstrated that computational modeling can provide valuable insights to improve the pre-procedural planning of TAVR-in-TAVR.
ABSTRACT
BACKGROUND: Volumetric Muscle Loss (VML), resulting from severe trauma or surgical ablation, is a pathological condition preventing myofibers regeneration, since skeletal muscle owns the remarkable ability to restore tissue damage, but only when limited in size. The current surgical therapies employed in the treatment of this pathology, which particularly affects military personnel, do not yet provide satisfactory results. For this reason, more innovative approaches must be sought, specifically skeletal muscle tissue engineering seems to highlight promising results obtained from preclinical studies in VML mouse model. Despite the great results obtained in rodents, translation into human needs a comparable animal model in terms of size, in order to validate the efficacy of the tissue engineering approach reconstructing larger muscle mass (human-like). In this work we aim to demonstrate the validity of a porcine model, that has underwent a surgical ablation of a large muscle area, as a VML damage model. RESULTS: For this purpose, morphological, ultrasound, histological and fluorescence analyses were carried out on the scar tissue formed following the surgical ablation of the peroneus tertius muscle of Sus scrofa domesticus commonly called mini-pig. In particular, the replenishment of the damaged area, the macrophage infiltration and the vascularization at different time-points were evaluated up to the harvesting of the scar upon six months. CONCLUSION: Here we demonstrated that following VML damage, there is an extremely poor regenerative process in the swine muscle tissue, while the formation of fibrotic, scar tissue occurs. The analyses performed up to 180 days after the injury revealed the development of a stable, structured and cellularized tissue, provided with vessels and extracellular matrix acquiring the status of granulation tissue like in human.
Subject(s)
Cicatrix , Muscular Diseases , Humans , Mice , Animals , Swine , Cicatrix/pathology , Longitudinal Studies , Swine, Miniature , Muscle, Skeletal/injuries , Muscle, Skeletal/pathology , Muscle, Skeletal/physiology , Muscular Diseases/pathologyABSTRACT
In human dystrophies, progressive muscle wasting is exacerbated by ectopic deposition of fat and fibrous tissue originating from fibro/adipogenic progenitors (FAPs). In degenerating muscles, the ability of these cells to promote successful healing is attenuated, and FAPs aberrantly expand and differentiate into adipocytes and fibroblasts. Thus, arresting the fibro/adipogenic fate of FAPs, without affecting their physiological role, represents a valuable therapeutic strategy for patients affected by muscle diseases. Here, using a panel of adipose progenitor cells, including human-derived FAPs, coupled with pharmacological perturbations and proteome profiling, we report that LY2090314 interferes with a genuine adipogenic program acting as WNT surrogate for the stabilization of a competent ß-catenin transcriptional complex. To predict the beneficial impact of LY2090314 in limiting ectopic deposition of fat in human muscles, we combined a poly-ethylene-glycol-fibrinogen biomimetic matrix with these progenitor cells to create a miniaturized 3D model of adipogenesis. Using this scalable system, we demonstrated that a two-digit nanomolar dose of this compound effectively represses adipogenesis at higher 3D scale, thus indicating the potential for LY2090314 to limit FAP-derived fat infiltrates in dystrophic muscles.
Subject(s)
Adipogenesis , Muscular Dystrophies , Humans , Muscles , Stem Cells , Muscle, Skeletal , Cell DifferentiationABSTRACT
Introduction: Tricuspid regurgitation (TR) is a relatively common valvular disease, which can result from structural abnormalities of any anatomic part of the tricuspid valve. Severe TR is linked to congestive heart failure and hemodynamic impairment, resulting in high mortality when repaired by elective surgery. This study was undertaken to quantify the structural and hemodynamic performance of the novel Transcatheter Bicaval Valves System (TricValve) percutaneously implanted in the superior vena cava (SVC) and inferior vena cava (IVC) of two patients with severe TR and venous congestion. Methods: After developing the SVC and IVC device models, the contact pressure exerted on the vena cava wall was obtained by computational analysis. Both smoothed-particle hydrodynamics (SPH) and computational fluid dynamics were carried out to quantify caval reflux in the right atrium and the pressure field of pre- and post-TricValve scenarios, respectively. Results: Analysis of contact pressure highlighted the main anchoring area of the SVC device occurring near the SVC device belly, while the IVC device exerted pronounced forces in the device's proximal and distal parts. SPH-related flow velocities revealed the absence of caval reflux, and a decrease in time-averaged pressure was observed near the SVC and IVC after TricValve implantation. Discussion: Findings demonstrated the potential of computational tools for enhancing our understanding of the biomechanical performance of structural tricuspid valve interventions and improving the way we design next-generation transcatheter therapies to treat the tricuspid valve with heterotopic caval valve implantation.
ABSTRACT
BACKGROUND: Initial data about the performance of the new-generation SAPIEN 3 Ultra (S3U) valve are highly promising. However, evidence about the longer-term performance and safety of the S3U is scarce. AIMS: We aimed to investigate the 1-year clinical and echocardiographic outcomes of transcatheter aortic valve implantation (TAVI) using the S3U compared with its predecessor, the SAPIEN 3 valve (S3). METHODS: The SAPIEN 3 Ultra registry included consecutive patients who underwent transfemoral TAVI at 12 European centres with the S3U or S3 between October 2016 and December 2020. One-to-one propensity score (PS) matching was performed to account for differences in baseline characteristics. The primary outcomes of interest were all-cause death and the composite of all-cause death, disabling stroke and hospitalisation for heart failure at 1 year. RESULTS: The overall study cohort encompassed 1,692 patients treated with either the S3U (n=519) or S3 (n=1,173). The PS-matched population had a total of 992 patients (496 per group). At 1 year, the rate of death from any cause was 4.9% in the S3U group and 6.3% in the S3 group (p=0.743). Similarly, there were no significant differences in the rates of the primary composite outcome (9.5% in the S3 group and 6.6% in the S3U group; p=0.162). The S3U was associated with lower rates of mild paravalvular leak (PVL) compared with the S3 (odds ratio 0.63, 95% confidence interval: 0.44 to 0.88; p<0.01). No significant differences in transprosthetic gradients were observed between the two groups. CONCLUSIONS: Compared with the S3, the S3U transcatheter heart valve was associated with similar 1-year clinical outcomes but reduced rates of mild PVL.
Subject(s)
Aortic Valve Stenosis , Heart Valve Prosthesis , Transcatheter Aortic Valve Replacement , Humans , Transcatheter Aortic Valve Replacement/adverse effects , Aortic Valve Stenosis/surgery , Heart Valve Prosthesis/adverse effects , Treatment Outcome , Registries , Aortic Valve/diagnostic imaging , Aortic Valve/surgery , Prosthesis DesignABSTRACT
BACKGROUND: The DISRUPT-CAD study series demonstrated feasibility and safety of intravascular lithotripsy (IVL) in selected patients, but applicability across a broad range of clinical scenarios remains unclear. AIMS: This study aims to evaluate the procedural and clinical outcomes of IVL in a high-risk real-world cohort, compared to a regulatory approval cohort. METHODS: Consecutive patients treated with IVL and percutaneous coronary intervention at our center from May 2016 to April 2020 were included. Comparison was made between those enrolled in the DISRUPT-CAD series of studies to those with calcified lesions but an exclusion criteria. RESULTS: Among 177 patients treated with IVL, 142 were excluded from regulatory trials due to acute coronary syndrome presentation (47.2%), left ventricular ejection fraction <40% (22.5%), chronic renal failure (12.0%), or use of mechanical circulatory support (8.5%). This clinical cohort had a higher SYNTAX score (22.6 ± 12.1 vs. 17.4 ± 9.9, p = 0.019), and more treated ACC/AHA C lesions (56.3% vs. 37.1%, p = 0.042). Rates of device success (93.7% vs. 100.0%, p = 0.208), procedural success (96.5% vs. 100.0%, p = 0.585), and minimal lumen area gain (221.2 ± 93.7% vs. 198.6 ± 152.0%, p = 0.807) were similar in both groups. The DISRUPT-CAD cohort had no in-hospital mortality, 30-day major adverse cardiac events (MACE), or 30-day target vessel revascularization (TVR). The clinical cohort had an in-hospital mortality of 4.2%, 30-day MACE of 7.8%, and 30-day TVR of 1.5%. There was no difference in 12-month TVR (2.9% vs. 2.2%; p = 0.825). Twelve-month MACE was higher in the clinical cohort (21.1% vs. 8.6%, p = 0.03). CONCLUSION: IVL use remains associated with high clinical efficacy, procedural success, and low complication rates in a real-world population previously excluded from regulatory approving trials.
ABSTRACT
Transcatheter mitral valve replacement (TMVR) has been used for "off-label" treatment when annuloplasty band ring for mitral repair fails. However, the complex anatomy and function of the mitral valve may lead to fatal complications as a result of the left ventricular outflow tract (LVOT) obstruction in TMVR. We report the structural and hemodynamic response of LVOT obstruction resulting from TMVR with the Edwards SAPIEN 3 Ultra (S3) device. We modified the original Living Heart Human Model (LHHM) to account for a failed mitral valve with an annuloplasty band ring and simulated the cardiac beating condition in the setting of S3 device implantation. Findings demonstrated a high dynamic behavior of the newly formed LVOT (neoLVOT) as confined by the displaced mitral valve and the interventricular septum. During the cardiac beat, the neoLVOT area oscillated from a maximum of 472.1â¯mm2 at early systole to the minimum of 183â¯mm2 at end-systole. The profile of both anchoring force and contact pressure revealed that the band ring serves as the anchoring zone while mitral valve is primally displaced by the deployed device. At early systole, computational flow dynamics highlighted hemodynamic disturbances associated with the LVOT obstruction, with a skewed flow towards the septum and a pressured drop of 4.5â¯mmHg between the left ventricular apex and the neoLVOT region. This study can lead to a more accurate assessment of the risk induced by the LVOT obstruction when stratifying patient anatomic suitability for TMVR.
Subject(s)
Heart Defects, Congenital , Heart Valve Prosthesis Implantation , Heart Valve Prosthesis , Mitral Valve Insufficiency , Ventricular Outflow Obstruction , Humans , Mitral Valve/surgery , Heart Valve Prosthesis Implantation/methods , Heart Valve Prosthesis/adverse effects , Cardiac Catheterization/adverse effects , Cardiac Catheterization/methods , Ventricular Outflow Obstruction/etiology , Ventricular Outflow Obstruction/surgery , Risk Factors , Treatment OutcomeABSTRACT
BACKGROUND: The latest iterations of devices for transcatheter aortic valve replacement (TAVR) have brought refinements to further improve patient outcomes. OBJECTIVES: This study sought to compare early outcomes of patients undergoing TAVR with the self-expanding (SE) Evolut PRO/PRO+ (Medtronic, Inc) or balloon-expandable (BE) Sapien 3 ULTRA (Edwards Lifesciences) devices. METHODS: The OPERA-TAVI (Comparative Analysis of Evolut PRO vs Sapien 3 Ultra Valves for Transfemoral Transcatheter Aortic Valve Implantation) registry collected data from 14 high-volume centers worldwide on patients undergoing TAVR with SE or BE devices. After excluding patients who were not eligible for both devices, patients were compared using 1:1 propensity score matching. The primary efficacy and safety outcomes were Valve Academic Research Consortium-3 device success and early safety, respectively. RESULTS: Among 2,241 patients eligible for the present analysis, 683 pairs of patients were matched. The primary efficacy outcome did not differ between patients receiving SE or BE transcatheter aortic valves (SE: 87.4% vs BE: 85.9%; P = 0.47), but the BE device recipients showed a higher rate of the primary safety outcome (SE: 69.1% vs BE: 82.6%; P < 0.01). This finding was driven by the higher rates of permanent pacemaker implantation (SE: 17.9% vs BE: 10.1%; P < 0.01) and disabling stroke (SE: 2.3% vs BE: 0.7%; P = 0.03) in SE device recipients. On post-TAVR echocardiography, the rate of moderate to severe paravalvular regurgitation was similar between groups (SE: 3.2% vs BE: 2.3%; P = 0.41), whereas lower mean transvalvular gradients were observed in the SE cohort (median SE: 7.0 vs BE: 12.0 mm Hg; P < 0.01). CONCLUSIONS: The OPERA-TAVI registry showed that SE and BE devices had comparable Valve Academic Research Consortium-3 device success rates, but the BE device had a higher rate of early safety. The higher permanent pacemaker implantation and disabling stroke rates in SE device recipients drove this composite endpoint.
Subject(s)
Heart Valve Prosthesis , Stroke , Transcatheter Aortic Valve Replacement , Humans , Stroke/etiology , Transcatheter Aortic Valve Replacement/adverse effects , Treatment OutcomeABSTRACT
Skeletal muscle is a very dynamic and plastic tissue, being essential for posture, locomotion and respiratory movement. Muscle atrophy or genetic muscle disorders, such as muscular dystrophies, are characterized by myofiber degeneration and replacement with fibrotic tissue. Recent studies suggest that changes in muscle metabolism such as mitochondrial dysfunction and dysregulation of intracellular Ca2+ homeostasis are implicated in many adverse conditions affecting skeletal muscle. Accumulating evidence also suggests that ER stress may play an important part in the pathogenesis of inflammatory myopathies and genetic muscle disorders. Among the different known proteins regulating ER structure and function, we focused on RTN-1C, a member of the reticulon proteins family localized on the ER membrane. We previously demonstrated that RTN-1C expression modulates cytosolic calcium concentration and ER stress pathway. Moreover, we recently reported a role for the reticulon protein in autophagy regulation. In this study, we found that muscle differentiation process positively correlates with RTN-1C expression and UPR pathway up-regulation during myogenesis. To better characterize the role of the reticulon protein alongside myogenic and muscle regenerative processes, we performed in vivo experiments using either a model of muscle injury or a photogenic model for Duchenne muscular dystrophy. The obtained results revealed RTN-1C up-regulation in mice undergoing active regeneration and localization in the injured myofibers. The presented results strongly suggested that RTN-1C, as a protein involved in key aspects of muscle metabolism, may represent a new target to promote muscle regeneration and repair upon injury.
ABSTRACT
Bicuspid aortic valve (BAV) patients are conventionally not treated by transcathether aortic valve implantation (TAVI) because of anatomic constraint with unfavorable outcome. Patient-specific numerical simulation of TAVI in BAV may predict important clinical insights to assess the conformability of the transcathether heart valves (THV) implanted on the aortic root of members of this challenging patient population. We aimed to develop a computational approach and virtually simulate TAVI in a group of n.6 stenotic BAV patients using the self-expanding Evolut Pro THV. Specifically, the structural mechanics were evaluated by a finite-element model to estimate the deformed THV configuration in the oval bicuspid anatomy. Then, a fluid-solid interaction analysis based on the smoothed-particle hydrodynamics (SPH) technique was adopted to quantify the blood-flow patterns as well as the regions at high risk of paravalvular leakage (PVL). Simulations demonstrated a slight asymmetric and elliptical expansion of the THV stent frame in the BAV anatomy. The contact pressure between the luminal aortic root surface and the THV stent frame was determined to quantify the device anchoring force at the level of the aortic annulus and mid-ascending aorta. At late diastole, PVL was found in the gap between the aortic wall and THV stent frame. Though the modeling framework was not validated by clinical data, this study could be considered a further step towards the use of numerical simulations for the assessment of TAVI in BAV, aiming at understanding patients not suitable for device implantation on an anatomic basis.
ABSTRACT
Volumetric muscle loss (VML) is the massive wasting of skeletal muscle tissue due to traumatic events or surgical ablation. This pathological condition exceeds the physiological healing process carried out by the muscle itself, which owns remarkable capacity to restore damages but only when limited in dimensions. Upon VML occurring, the affected area is severely compromised, heavily influencing the affected a person's quality of life. Overall, this condition is often associated with chronic disability, which makes the return to duty of highly specialized professional figures (e.g., military personnel or athletes) almost impossible. The actual treatment for VML is based on surgical conservative treatment followed by physical exercise; nevertheless, the results, in terms of either lost mass and/or functionality recovery, are still poor. On the other hand, the efforts of the scientific community are focusing on reconstructive therapy aiming at muscular tissue void volume replenishment by exploiting biomimetic matrix or artificial tissue implantation. Reconstructing strategies represent a valid option to build new muscular tissue not only to recover damaged muscles, but also to better socket prosthesis in terms of anchorage surfaces and reinnervation substrates for reconstructed mass.
ABSTRACT
The importance of skeletal muscle tissue is undoubted being the controller of several vital functions including respiration and all voluntary locomotion activities. However, its regenerative capability is limited and significant tissue loss often leads to a chronic pathologic condition known as volumetric muscle loss. Here, we propose a biofabrication approach to rapidly restore skeletal muscle mass, 3D histoarchitecture, and functionality. By recapitulating muscle anisotropic organization at the microscale level, we demonstrate to efficiently guide cell differentiation and myobundle formation both in vitro and in vivo. Of note, upon implantation, the biofabricated myo-substitutes support the formation of new blood vessels and neuromuscular junctions-pivotal aspects for cell survival and muscle contractile functionalities-together with an advanced muscle mass and force recovery. Altogether, these data represent a solid base for further testing the myo-substitutes in large animal size and a promising platform to be eventually translated into clinical scenarios.