Muscle Transplantation Research Articles

Direct extrusion of multifascicle prevascularized human skeletal muscle for volumetric muscle loss surgery

Skeletal muscle is composed of multiple fascicles, which are parallel bundles of muscle fibers surrounded by connective tissues that contain blood vessels and nerves. Here, we fabricated multifascicle human skeletal muscle scaffolds that mimic the natural structure of human skeletal muscle bundles using a seven-barrel nozzle. For the core material to form the fascicle structure, human skeletal myoblasts were encapsulated in Matrigel with calcium chloride. Meanwhile, the shell that plays a role as the connective tissue, human fibroblasts and human umbilical vein endothelial cells within a mixture of porcine muscle decellularized extracellular matrix and sodium alginate at a 95:5 ratio was used. We assessed four types of extruded scaffolds monolithic-monoculture (Mo-M), monolithic-coculture (Mo–C), multifascicle-monoculture (Mu-M), and multifascicle-coculture (Mu-C) to determine the structural effect of muscle mimicking scaffold. The Mu-C scaffold outperformed other scaffolds in cell proliferation, differentiation, vascularization, mechanical properties, and functionality. In an in vivo mouse model of volumetric muscle loss, the Mu-C scaffold effectively regenerated the tibialis anterior muscle defect, demonstrating its potential for volumetric muscle transplantation. Our nozzle will be further used to produce other volumetric functional tissues, such as tendons and peripheral nerves.

The Role of Length of Nerve Grafts in Combination with Free Functional Muscle Transplantation for Brachial Plexus Injury: A Single-Center Experience.

Extensive lesions of the brachial plexus, or late cases, require free functional muscle grafts because the expected recovery time exceeds the critical threshold of 1.5 years, beyond which irreversible damage may be expected in the distal nerve stump and in the muscle. The reconstructive concept consists of a two-stage procedure where, in the first step, a nerve transfer is performed (from ipsi- or contralateral donor nerves). In the second step, after successful axonal regeneration within the graft has been confirmed, a free muscle transfer is performed. These grafts often exceed 40 cm in length, particularly for contralateral transfers. The purpose of this study was to assess whether robust motor recovery could be supported by such long nerve grafts. From April 2004 to April 2023, a total of 327 free functional muscle transfers were performed, the nerve graft length ranging from 0 cm (direct coaptation) to 90 cm (serial grafts). Motor recovery was evaluated 1.5 years after surgery according to the MRC scale. A total of 208 patients were available for follow up. Direct coaptation yielded the best results, with 83% of patients reaching an M3 or M4 level of muscle strength. With the application of long (30-60 cm) grafts, 73% of the patients were classified as M3 or M4. The application of serial nerve grafts, however, only resulted in 18% of patients achieving a motor recovery rating of M3. These findings demonstrate that robust motor regeneration is supported by long (30-60 cm) nerve grafts, whereas serial nerve grafting results in a marked reduction in the quality of regeneration.

Current Methodologies for Inducing Aligned Myofibers in Tissue Constructs for Skeletal Muscle Tissue Regeneration.

Significance: Volumetric muscle loss (VML) results in the loss of large amounts of tissue that inhibits muscle regeneration. Existing therapies, such as autologous muscle transfer and physical therapy, are incapable of returning full function and force production to injured muscle. Recent Advances: Skeletal muscle tissue constructs may provide an alternative to existing therapies currently used to treat VML. Unlike autologous muscle transplants, muscle constructs can be cultured in vitro and are not reliant on intact muscle tissue. Skeletal muscle constructs can be generated from small muscle biopsies and could be used to generate skeletal muscle tissue constructs to replace injured tissues. Critical Issues: To serve as effective therapies, muscle constructs must be capable of generating contractile forces that can assist the function of host skeletal muscle. The contractile force of native muscle arises in part as a consequence of the highly aligned, bundled architecture of myofibers. Attempts to induce similar alignment include applications of tension/strain across hydrogels, inducing aligned architectures within scaffolds, casting tissues in straited molds, and 3D printing. While all these methods have demonstrated efficacy toward inducing myofiber alignment, the extent of myofiber alignment, tissue formation, and force production varies. This manusript critically reviews the advantages and limitations of these methods and specifically discusses their ability to impart mechanical and architectural cues to induce alignment within tissue constructs. Future Directions: As tissue-synthesizing techniques continue to improve, muscle constructs must include more cell types than simply myoblasts, such as the addition of neuronal and endothelial cells. Higher-level tissue organization is critical to the success of these constructs. Many of these technologies have yet to be implanted into host tissue to understand engraftment and how they can contribute to traumatic injury, and as such continued collaboration between surgeons and tissue engineers is necessary to ultimately result in clinical translation.

Dynamic Repair Surgery for Late-Stage Facial Paralysis: Advances in Restoring Movement and Function.

Purpose: Facial paralysis results from congenital or acquired facial nerve damage, leading to significant cosmetic and functional deficits. Surgical resection of parotid and midface tumors can cause facial paralysis, necessitating effective treatment strategies. This review addresses the challenge of restoring movement and function in late-stage facial paralysis, focusing on dynamic repair techniques involving nerve and muscle transplantation. Methods: The review encompasses studies on dynamic repair surgery for late facial paralysis, including techniques such as local muscle flap with pedicle transfer, vascularized nerve flap with pedicle transfer, and multiple muscle flap procedures. A systematic literature search was conducted using PubMed, Web of Science, and Google Scholar, covering studies from 2000 to 2024. Keywords included "dynamic repair", "late-stage facial paralysis", "nerve and muscle transplantation", "muscle flap", and "tendon transposition". Included were clinical studies, systematic reviews, and meta-analyses reporting surgical outcomes. Exclusion criteria included studies with insufficient data and non-peer-reviewed articles. Results: Dynamic repair techniques involving nerve and muscle transplantation are essential for treating late-stage facial paralysis. Each surgical method has strengths and limitations. The masseter muscle flap demonstrates high success rates, although it can cause horizontal tension and jaw contour issues. The temporalis muscle flap is effective for smile restoration but may lead to temporal concavity. The gracilis muscle flap is widely used, especially with dual nerve innervation, showing high success in spontaneous smiles but requiring a longer recovery period. The latissimus dorsi flap is effective but can cause edema and shoulder issues. The serratus anterior free flap offers flexibility with precise vector positioning but may not achieve adequate lip elevation and can cause cheek swelling. Combined multi-flap surgeries provide more natural facial expressions but increase surgical complexity and require advanced microsurgical skills. Conclusions: Dual nerve innervation shows promise for restoring spontaneous smiles. One-stage surgery offers faster recovery and reduced financial burden. Comprehensive patient evaluation is crucial to select the most suitable surgical method. Dynamic repair techniques involving nerve and muscle transplantation provide effective solutions for restoring function and aesthetics in late-stage facial paralysis. Future research should focus on long-term outcomes, patient satisfaction, and standardizing surgical protocols to optimize treatment strategies.

Extraocular Muscle Transplantation Surgery for Primary Treatment of Extra Large-angle Squint.

Large-angle horizontal ocular deviations will commonly require bilateral surgery to correct the primary ocular deviation. However, considering the need for full correction with one surgical procedure and patients' reluctance to be operated on the good eye, such large horizontal ocular deviations may be managed with true muscle transplantation. The authors present a case series of patients who underwent this procedure and develop a surgical table to guide management. Patients with horizontal squints measuring 80 prism diopters (PD) or larger in all age groups who underwent extraocular muscle transplantation surgery between January 2019 and June 2022 in Nigeria were included. Preoperative deviation of the squint, sensory evaluation, surgical dosage, and outcomes were documented. Part of the resected muscle was transplanted to give additional recession in the antagonist muscle. Success was defined as deviation corrected by 60% or more or postoperative ocular alignment within 10 PD or less, six weeks postoperatively. Fourteen patients with extra-large-angle strabismus were operated. Male/female ratio was 0.6:1. Mean preoperative deviation of 89.6 9.3 collapsed to 6.6 1.8 PD at six weeks and continued to improve to a mean deviation of 2.5 PD at six months postoperatively. When the subgroup of patients who were 18 years were analyzed, the outcome was equally successful; preoperative deviation of 89.4 PD collapsed to 1.4 PD, six months postoperatively. There were equal success rates when those with sensory strabismus were compared with those with binocular vision; preoperative deviation of 92.5 PD in the sensory group and 88.5 PD in the binocular group collapsed to 5.9 PD and 1 PD, respectively, six months after surgery. A viable alternative for treating extra-large-angle strabismus in adults and children in developing countries was described with good postoperative outcome. In addition, a new expanded surgical dosage table for muscle transplantation surgery corrections of up to 130 PD was developed.

Delayed nerve reconstruction for brachial plexus injuries: is the risk worth the reward?

Nerve reconstruction after 6 months of denervation time in brachial plexus injuries (BPIs) can be inconsistent. A dilemma exists when the use of critical donor nerves for nerve transfers may lead to unreliable outcomes that would waste the donor nerve. The purpose of this study was to evaluate the long-term outcomes of elbow and shoulder function in patients with BPIs receiving nerve reconstruction in the delayed setting (i.e., 6-12 months after injury). Data from patients with delayed BPIs who received a nerve transfer (including proximal and distal nerve transfer/grafting) at a tertiary medical center were retrospectively collected from January 1999 to March 2020. Demographics, extent of injury, mechanism of injury, and reconstructive methods were collected. Patients were categorized into two groups: non-pan-plexus BPI (C5-6, C5-7, and C5-8) and pan-plexus BPI (C5-T1). Acceptable outcome was defined as elbow flexion ≥ M3 status or shoulder abduction ≥ 60°. Sixty-four patients were included in the study. The average time from injury to nerve reconstruction was 236 (range 180-441) days, and the average follow-up time was 66 months. In the non-pan-plexus BPI group (n = 43 patients), 74.4% of patients demonstrated M3 elbow flexion, and 48.8% of patients demonstrated M4 elbow flexion. Double fascicular transfer yielded better results and faster recovery than a single fascicular transfer. In the pan-plexus BPI group (n = 21 patients), 38.1% of patients reached M3 elbow flexion and 23.8% attained M4 elbow flexion. In the non-pan-plexus BPI group, the recovery rate of acceptable shoulder abduction was 53.5%, but only 23.5% of pan-plexus patients with BPI achieved acceptable shoulder abduction. Nerve reconstruction can effectively restore functional elbow flexion and acceptable shoulder abduction in non-pan-plexus patients with BPI in the delayed setting. However, neither acceptable elbow flexion nor shoulder abduction could be consistently achieved in pan-plexus BPI. Judicious use of the donor nerves in pan-plexus injuries is required, in addition to preserving a donor nerve for a backup plan such as free-functioning muscle transplantation or tendon transfers.

SURGICAL OUTCOME OF MUSCLE TRANSPLANTATION AS A MONOCULAR SURGERY FOR LARGE ANGLE STRABISMUS

Introduction: The management of large-angle strabismus can be difficult for surgeons, and successful outcomes may require multiple surgeries. However, modern surgical techniques aim to achieve desired results with a single operation. Muscle transplantation is one such technique that increases the effective muscle length, allowing for a large correction in a one-stage surgery. Objective: To report the outcome of muscle transplantation surgery in large-angle strabismus. Case Illustration: Three patients presented with large-angle strabismus, of which two cases showed >50∆ ET and one case had >50∆XT. All patients had normal anterior and posterior segment findings and underwent muscle transplantation under general anaesthesia. The first and second cases showed good alignment post-surgery, with no limitations in ocular motility in all gaze directions and improved visual acuity. However, none of the cases achieved stereoscopic vision due to chronic strabismus. In the third case, improvement in the primary position was observed two weeks post-operative, but ocular motility still had limitations. Conclusion: Muscle transplantation is a good option to correct large-angle strabismus, specifically in the unilateral case in a single procedure.

Functional outcomes of reconstructive flap surgery for soft tissue sarcoma: Long-term outcomes of functional restoration using innervated muscle transplantation

Functional outcomes associated with prognostic factors and innervated muscle transplantation after wide soft tissue sarcoma resection remain unclear. We examined the functional outcomes of reconstructive flap surgery for soft tissue sarcoma retrospectively. Twenty patients underwent innervated muscle transplantation with pedicled or free flaps for functional reconstruction of resected muscles. Thirteen latissimus dorsi muscles and one vastus lateralis muscle combined with an anterolateral thigh flap were transferred as free flaps using the epi-perineural suture technique. Six latissimus dorsi muscles were transferred as pedicled flaps with neural continuity. Postoperative functional outcomes were assessed using the Musculoskeletal Tumor Society (MSTS) scores for the upper and lower extremities of 22 and 24 patients, respectively. The mean MSTS score for all patients was 82.3 at 12 months postoperatively. The mean scores for patients who underwent reconstruction with pedicled and free flaps were 89.2 and 77.1, respectively. The MSTS scores for the lower extremity, tumor size ≥5cm, and free flap reconstruction were significantly lower than those for the upper extremity, tumor size <5cm, and pedicled flap reconstruction (P=0.02, 0.37, and 0.008, respectively). The postoperative MSTS score for innervated muscle transplantation was 76.7 at 12 months and was significantly higher (83.7) at 24 months (P=0.003). Functional outcomes were significantly associated with tumor location, tumor size, and reconstructive flap type based on the MSTS scores. Innervated muscle transplantation improved functional outcomes at 24 months postoperatively via sufficient recovery of the innervated muscle, not the compensatory recovery of the remaining muscle.

Evaluation of the effects of ischemia-reperfusion injury in rat isogenic and allogeneic muscle and skin transplant models.

Ischemia-reperfusion injury (IRI) is a phenomenon that affects transplant survival. The aim of our study was to examine the effects of IRI in isogenic and allogeneic muscle and skin transplantation models exposed to prolonged warm ischemia. Forty-eight Lewis rats and 16 Brown-Norway rats were used to create four groups: Isogenic Inguinal Flap Transplantation (IST), Isogenic Gastrocnemius Muscle Flap Transplantation (IMT), Allogeneic Inguinal Flap Transplantation (AST), and Allogeneic Gastrocnemius Muscle Flap Transplantation (AMT). Malonyldialdehyde (MDA) and superoxide dismutase (SOD) levels were measured on postoperative days 1, 7, 21, 35, 63, 100, and 120 in all groups. Donor-specific chimerism (DSC) in peripheral blood was evaluated in the allogeneic groups on postoperative days 7, 21, 35, 63, 100, and 120. The microRNA-21 and microRNA-205 levels were evaluated on postoperative days 1, 7, and 120 in all groups. At the end of the study, a histopathological examination was performed. A statistically significant difference was found between the groups in terms of MDA and SOD levels. DSC was detected in the AMT group. A significant increase in microRNA-205 was observed, especially in the AMT group. There was no significant difference in the number of functional muscle units between the muscle transplantation groups. The presence of DSC in the AMT group and the lack of a significant difference in the number of functional muscle units in the IMT and AMT groups are noteworthy findings.

Gracilis Flap Restoring Quality of Life in a Patient with Non Functional Anal Sphincter

An excellent technique for reconstructing the perineum following extensive perineal resection for restoration of a traumatised anal sphincter is the Gracilis myocutaneous flap. Direct anal trauma or pelvic injuries can separate the anal sphincters. An overlapping sphincteroplasty has a fair possibility of regaining acceptable fecal continence if roughly half of the sphincter ring is still functional. A case of a 22-year-old male who underwent Gracilis myocutaneous flap reconstruction after being diagnosed with a non functioning anal sphincter is reported. A free muscle transplant was done to repair the sphincter, utilising denervated muscle with an intact blood supply. New muscle was attached to those sphincter muscles which were still functional. The transplanted muscle receives new muscular fibers, enabling the repaired sphincter to contract voluntarily in addition to reflexively. The surgical approach is determined based on the presented sphincter defect. Free muscle transplantation can be preferred in cases where the external sphincter has some degree of functionality.

Combining Surgical Innovations in Amputation Surgery-Robotic Harvest of the Rectus Abdominis Muscle, Transplantation and Targeted Muscle Reinnervation Improves Myocontrol Capability and Pain in a Transradial Amputee.

Adding robotic surgery to bionic reconstruction might open a new dimension. The objective was to evaluate if a robotically harvested rectus abdominis (RA) transplant is a feasible procedure to improve soft-tissue coverage at the residual limb (RL) and serve as a recipient for up to three nerves due to its unique architecture and to allow the generation of additional signals for advanced myoelectric prosthesis control. A transradial amputee with insufficient soft-tissue coverage and painful neuromas underwent the interventions and was observed for 18 months. RA muscle was harvested using robotic-assisted surgery and transplanted to the RL, followed by end-to-end neurroraphy to the recipient nerves of the three muscle segments to reanimate radial, median, and ulnar nerve function. The transplanted muscle healed with partial necrosis of the skin mesh graft. Twelve months later, reliable, and spatially well-defined Hoffmann-Tinel signs were detectable at three segments of the RA muscle flap. No donor-site morbidities were present, and EMG activity could be detected in all three muscle segments. The linear discriminant analysis (LDA) classifier could reliably distinguish three classes within 1% error tolerance using only the three electrodes on the muscle transplant and up to five classes outside the muscle transplant. The combination of these surgical procedure advances with emerging (myo-)control technologies can easily be extended to different amputation levels to reduce RL complications and augment control sites with a limited surface area, thus facilitating the usability of advanced myoelectric prostheses.

Treatment of Complete Brachial Plexus Injuries Using Double Free Muscle Transfer

The purpose of this study was to examine the surgical outcomes of double free muscle transfer (DFMT) performed in patients with complete brachial plexus injury (BPI). We retrospectively analyzed the outcomes of DFMT for 12 patients with complete BPI who were followed up for more than 2 years after the final muscle transplantation. Their mean age was 29 years (range, 18-41). Three patients underwent contralateral C7 nerve root transfer before the DFMT. The range of motion (ROM) of the shoulder, elbow, and fingers was measured. Patient-reported outcome measures, including Disability of the Shoulder, Arm, and Hand (DASH) scores and visual analog scale (VAS) scores for pain, were also examined. The mean shoulder ROM against gravity was 22° ± 8° in abduction and 33° ± 5° in flexion. Seven patients underwent phrenic nerve (PhN) transfer to the suprascapular nerves, and five exhibited asymptomatic lung impairment on spirography more than 2 years after PhN transfer. The mean elbow ROM against gravity was 111° ± 9° in flexion and -32° ± 7° in extension. All patients obtained elbow flexion >90° against a 0.5-kg weight. All patients obtained touch sensation and two recognized warm and cold sensations in the affected palm. The mean total active motion of the affected fingers was 44° ± 11°. All patients exhibited hook function of the hands. The mean preoperative and postoperative DASH scores were 70.3 ± 13.4 and 51.8 ± 15.9, respectively. The mean pain VAS score was 28 ± 31 at the final follow-up. Double free muscle transfer provided patients with complete brachial plexus palsy with good elbow flexion and hand hook functions. Therapeutic IV.

Correlation between preoperative MRI measurement of cross-sectional area of hamstring tendon and graft in anterior cruciate ligament reconstruction

To study the corretation between the cross-sectional area of hamstring tenden measured by MRI and gragt in anterior cruciate ligament rexonstruction. MRI data of 50 patients who planned to undergo anterior cruciate ligament reconstruction from November 2021 to March 2022 were collected, including 32 males and 18 females, aged from 19 to 48 years old with an average of(31.1±8.7) years. Before the operation, the semitendinosus and gracilis tendons were measured and recorded by MRI, and then the anterior cruciate ligament was reconstructed under arthroscope. During the operation, gracilis and semitendinosus tendons were taken to prepare the final tendon to be transplanted, and the diameter of the prepared final graft was measured during the operation. Finally, the data were analyzed by statistical software. The cross sectional areas of semitendinosus tendon, gracilis tendon, semitendinosus tendon and gracilis tendon measured by MRI were significantly and positively correlated with the diameter of grafts required in anterior cruciate ligament surgery, the r values were 0.858, 0.728, 0.842(P<0.001), respectively. The area under curre (AUC), sensitivity, and specificity of the sum of the cross sectional areas of semitendinosus tendon and gracilis tendon were 0.925, 90.48%, and 85.71%, respectively. In patients undergoing anterior cruciate ligament reconstruction, preoperative MRI measurement has a strong statistical correlation with the diameter of hamstring muscle transplantation during operation. The sum of the cross sectional areas of semitendinosus tendon and gracilis tendon has a high predictive value for the diameter of grafts during anterior cruciate ligament reconstruction, and can predict the size of grafts during operation.

Division of neuromuscular compartments and localization of the center of the intramuscular nerve-dense region in pelvic wall muscles based on Sihler's staining.

The innervation of the pelvic wall muscles is not very clear. This study aimed to reveal the division of neuromuscular compartments and localize the surface position and depth of the center of the intramuscular nerve-dense region (CINDR) of the pelvic wall muscles based on Sihler's staining. Twenty-four adult cadavers were used. To localize the CINDR of the pelvic wall muscles, horizontal (H) and longitudinal (L) reference lines were drawn, and Sihler's staining was used to reveal the intramuscular nerve distribution. The CINDR projection points (P and P' points) behind and in front of the body surface, the positions of the P points projected onto the H and L lines (PH and PL points), and the depth of CINDR were determined by spiral computed tomography scanning. The piriformis and obturator internus muscles can be divided into two and three neuromuscular compartments, respectively. The PH of CINDR of the piriformis muscle was located at 22.61 ± 2.66% of the H line, the PL was at 28.53 ± 6.08% of the L line, and the puncture depth of the piriformis muscle was at 24.64 ± 2.16% of the PP' line. The PH of CINDR of the obturator internus muscle was at 16.49 ± 1.20% of the H line, the PL was at 10.94 ± 1.09% of its L line, and the puncture depth was 6.26 ± 0.38cm. These findings may guide the design of the compartmentalized transplantation of the pelvic wall muscles and improve the target localization efficiency and efficacy for injecting botulinum toxin A to treat pelvic wall muscle spasm.

A pilot randomized clinical trial comparing muscle transplant versus hang back recession in extra-large angle exotropia

ABSTRACT Purpose For extra-large angle exotropia (>60 prism diopters, PD), single-setting surgical alternatives are scarce; frequently, more than two muscle or two eye procedures are indicated. To evaluate the viability of single eye surgery, a current randomized comparative trial is undertaken. Methods Twenty adult patients with extra-large angle exotropia underwent a thorough orthoptic evaluation before being divided into two groups at random. Ten patients in group 1 underwent medial rectus resection (5.5–7.5 mm), followed by transplant-aided lateral rectus recession (effective length: 4–5.5 mm) (9 mm). In group two, ten different patients underwent medial rectus resection (5.5–7 mm), but this time, the lateral rectus recession (9 mm) was aided with a hang-back suture (5–7 mm). The two procedures were compared at baseline and six months post-operatively. Results There was no significant difference in the groups’ median ages (P = .95). In groups one and two, the median corrections achieved were 81.00 (79.50–85.50) PD and 81.00 (79.75–86.50) PD, respectively. The differences in corrections were statistically insignificant (p = .99). In all patients, abduction limitation was frequently noted in the immediate post-operative period, which improved over time. In each group, there were two patients (>90 prisms) with residual deviation of at least 30 PD, for which the contralateral eyes were operated. Conclusions The hang-back recession was as successful as muscle transplant procedure in correcting 80–90 PD of exotropia with notable clinical benefits and ease.

Oral administration of a locally isolated Lactobacillus rhamnosus (NR_113332.1) improves regeneration of extensor digitorum longus muscle in mice

ObjectiveThe aim of this study was to examine the effects of probiotic supplementation on extensor digitorum longus (EDL) regeneration after grafting in mice. MethodsEDL muscles were ortho-transplanted in mice. The experimental group was given 1 × 108 colony-forming units/g body weight of Lactobacillus rhamnosus daily after EDL muscle transplantation surgeries. EDL muscle transplants were recovered after 3, 5, 7, and 14 d post-transplantation from the control as well as the experimental animals and processed for histologic analysis. ResultsAt day 3 post-transplantation, the inflammatory cells had infiltrated into the grafted EDL muscles and the central section of the grafted tissue contained necrotic fibers. At day 5 post-transplantation, the concentration of inflammatory cells increased further and degenerative muscle fibers were being replaced with centrally nucleated muscle cells. The average cross-sectional area non-grafted EDL and grafted muscle in the probiotic supplemented mice at day 7 increased to 48% and 23% (P = 0.002), respectively, compared with the respective values in the control animals. Whereas in non-grafted and grafted EDL muscle it could approach 8% and 36% (P = 0.008), respectively at 14 d compared with the corresponding values of the control EDL muscle transplants. The number of muscle fibers in the non-grafted and grafted probiotic-supplemented groups increased to12% and 20% (P = 0.045) at day 7 compared with the control EDL muscle. In non-grafted and grafted EDL muscle, the number of regenerated muscle fibers increased to 73% and 64% (P = 0.110) at day 14 compared with control EDL grafted muscle. ConclusionResults of the present study regarding better regeneration of skeletal muscle fibers in the probiotic-supplemented mice than the control grafts warrant further molecular-level investigation to understand the underlying mechanism mediating the process of skeletal muscle fiber regeneration. Probiotics possibly modulate the process of muscle fiber regeneration by adjusting the composition of gut microbiota.

Transposition of functioning muscles in complex treatment of adult patients with injuries of the bracheric plexus (literature review)

Introduction. Injuries to the brachial plexus are one of the most severe types of injuries to the nerves of the upper limb, and variants with the separation of the roots from the spinal cord represent a very difficult category of injuries to treat. Among patients who have received such injuries, there is a very high incidence of disability, since it is possible to achieve only partial restoration of the function of the upper limb. Recently, the method of transposition of functioning muscles has been growing in popularity due to its reliability and relatively short recovery time of function.The purpose of the work is to analyze the literature data on the possibility of using the method of transposition of functioning muscles in the complex treatment of victims with brachial plexus injuries.The authors have searched PubMed and RSCI databases over the past 25 years for keywords: peripheral nerve damage, tendon transposition, transposition of functioning muscles, nerve injury, brachial plexus injury, spinal cord root avulsion. In the selected 23 most relevant papers, the muscles used for transposition, indications and timing of operations, results and complications were analyzed, compared with other methods of surgical treatment of brachial plexus injuries. The analysis of studies has shown that the transposition of functioning muscles allows in most cases to restore the target movement to the useful level of M3–M4 on the MRC scale, is a more reliable method and allows achieving better results, especially in patients with severe complete injuries of the brachial plexus. An important disadvantage of free hip thin muscle transplantation operations is the risk of microanastomosis thrombosis, which requires detailed preoperative planning and good microsurgical technique of the operating team.Conclusion. Free transplantation of 2 functioning muscles is currently the method of choice for restoring upper limb movements in patients with complete brachial plexus injuries.

Bioprinted Notch ligand to function as stem cell niche improves muscle regeneration in dystrophic muscle.

299In Duchenne muscular dystrophy, dystrophic muscle phenotypes are closely associated with the exhaustion of muscle stem cells. Transplantation of muscle stem cells has been widely studied for improving muscle regeneration, but poor cell survival and self-renewal, rapid loss of stemness, and limited dispersion of grafted cells following transplantation have collectively hindered the overall success of this strategy. Optimized mechanisms for maintaining and improving stem cell function are naturally present in the microenvironment of the stem cell niche in healthy muscles. Therefore, one logical strategy toward improving stem cell function and efficiency of stem cell transplantation in diseased muscles would be the establishment of a microenvironment mimicking some key aspects of healthy native stem cell niches. Here, we applied inkjet-based bioprinting technology to engineer a mimicked artificial stem cell niche in dystrophic muscle, comprising stem cell niche regulating factors (Notch activator DLL1) bioprinted onto 3D DermaMatrix construct. The recombinant DLL1 protein, DLL1 (mouse): Fc (human) (rec), was applied here as the Notch activator. Bioprinted DermaMatrix construct was seeded with muscle stem cells in vitro, and increased stem cell maintenance and repressed myogenic differentiation process was observed. DLL1 bioprinted DermaMatrix construct was then engrafted into dystrophic muscle of mdx/scid mice, and the improved cell engraftment and progression of muscle regeneration was observed 10 days after engraftment. Our results demonstrated that bioprinting of Notch activator within 3D construct can be applied to serve as muscle stem cell niche and improve the efficacy of muscle stem cell transplantation in diseased muscle.

Resolving Co-Contraction of the Elbow in Patient with Sequelae of Obstetric Brachial Plexus Palsy: A Cohort Study.

Obstetric brachial plexus palsy can cause deformities of the upper extremity in up to 92% of patients. Elbow reconstruction is difficult because co-contraction of the elbow flexor (EF) and elbow extensor (EE) muscles makes the traditional treatment strategy ineffective. The authors propose a novel strategy to minimize the effect of co-contraction, comprising transfer of an EF to the triceps and a staged gracilis muscle transplantation [functioning free muscle transplantation (FFMT)] to augment EF. The authors hypothesize this will lead to improved elbow flexion and extension, as well as decreased elbow flexion contracture. A single-center retrospective review of patients who received a gracilis FFMT for EF after EF-to-EE transfer was performed. EF/EE strength and range of motion data were collected from the last clinical visit. Patients were excluded if they had fewer than 1.5 years of follow-up. A control group with sequelae of obstetric brachial plexus palsy and nonsurgical treatment was used for comparison. Twenty-one patients were included. Average age at muscle transfer was 7.6 ± 5.5 years (range, 3 to 22 years) and at gracilis FFMT was 10.4 ± 6.0 years (range, 5 to 26 years). Average follow-up was 7.3 ± 6.5 years (range, 1.5 to 14.8 years). After EF-to-EE transfer, EE strength increased significantly from Medical Research Council grade 2.2 ± 0.4 to 3.4 ± 0.5 ( P < 0.0001) and EF decreased from 3.2 ± 1.1 to 1.1 ± 1.1 ( P < 0.0001) and recovered to grade 3.3 ± 0.7 after gracilis FFMT. EF contracture was significantly lower compared with that in the nonsurgical cohort ( P = 0.029). Patients who undergo EF-to-EE transfer followed by gracilis FFMT have equivalent EF strength with significantly improved EE and improved elbow flexion contracture. Therapeutic, IV.

Algal-derived macromolecules and their composites: From synthetic biology to biomedical applications in bone and cardiovascular tissue engineering

Algae have shown numerous advantages as biofunctional and bioactive material sources. The development of biosynthetic or synthetic materials has enabled algal-derived macromolecules and their derivatives to be used in biomedical applications. This review examines and analyzes the most recent developments in the production of biomaterials from algal-derived macromolecules and their composites and their potential applications in bone and cardiovascular tissue engineering. Several macromolecules derived from algal polysaccharides, including sulfated polysaccharides, fucoidans, and fucans, have been developed for cartilage, intervertebral disc, bone, and skeletal muscle transplants because of their stable structures. Alginates, fucoidans, chitin, porphyrin, and other algal polysaccharide derivatives have been investigated for engineering blood vessels, heart valves, and even the liver. One advantage of algal-derived macromolecules and composites is their safe immunity properties. This review also highlights cutting-edge developments in applying algal-derived macromolecules with a broader biomedical scope to encourage in-depth research into their potential as biomaterial scaffolds in medical applications.