Motor Activity-Induced White Matter Repair in White Matter Stroke.

Subcortical white matter stroke (WMS) is a progressive disorder which is demarcated by the formation of small ischemic lesions along white matter tracts in the CNS. As lesions accumulate, patients begin to experience severe motor and cognitive decline. Despite its high rate of incidence in the human population, our understanding of the cause and outcome of WMS is extremely limited. As such, viable therapies for WMS remain to be seen. This study characterizes myelin recovery following stroke and motor learning-based rehabilitation in a mouse model of subcortical WMS. Following WMS, a transient increase in differentiating oligodendrocytes occurs within the peri-infarct in young male adult mice, which is completely abolished in male aged mice. Compound action potential recording demonstrates a decrease in conduction velocity of myelinated axons at the peri-infarct. Animals were then tested on one of three distinct motor learning-based rehabilitation strategies (skilled reach, restricted access to a complex running wheel, and unrestricted access to a complex running wheel) for their capacity to induce repair. These studies determined that unrestricted access to a complex running wheel alone increases the density of differentiating oligodendrocytes in infarcted white matter in young adult male mice, which is abolished in aged male mice. Unrestricted access to a complex running wheel was also able to enhance conduction velocity of myelinated axons at the peri-infarct to a speed comparable to naive controls suggesting functional recovery. However, there was no evidence of motor rehabilitation-induced remyelination or myelin protection.SIGNIFICANCE STATEMENT White matter stroke is a common disease with no medical therapy. A form of motor rehabilitation improves some aspects of white matter repair and recovery.

Experimental structure based drug design (SBDD) applications for anti-leishmanial drugs: A paradigm shift?

Leishmaniasis is a group of neglected tropical diseases caused by at least 20 species of Leishmania protozoa, which are spread by the bite of infected sandflies. There are three main forms of the disease: cutaneous leishmaniasis (CL, the most common), visceral leishmaniasis (VL, also known as kala-azar, the most serious), and mucocutaneous leishmaniasis. One billion people live in areas endemic to leishmaniasis, with an annual estimation of 30,000 new cases of VL and more than 1 million of CL. New treatments for leishmaniasis are an urgent need, as the existing ones are inefficient, toxic, and/or expensive. We have revised the experimental structure-based drug design (SBDD) efforts applied to the discovery of new drugs against leishmaniasis. We have grouped the explored targets according to the metabolic pathways they belong to, and the key achieved advances are highlighted and evaluated. In most cases, SBDD studies follow high-throughput screening campaigns and are secondary to pharmacokinetic optimization, due to the majoritarian belief that there are few validated targets for SBDD in leishmaniasis. However, some SBDD strategies have significantly contributed to new drug candidates against leishmaniasis and a bigger number holds promise for future development.

GIST is not all that it seems.

We present a 41-year-old female who was admitted to our hospital with a history of 2-month epigastric pain and vomiting. Physical examination was normal. Upper gastrointestinal endoscopy showed a sessile submucosal tumor with central ulceration in the gastric body-antrum. Biopsies revealed a gastric mucosa without changes. Nevertheless, endoscopic ultrasound-guided biopsies showed interlacing bundles of spindle cells. The immunohistochemical study was negative for CD117 and smooth muscle actin and positive for S100 protein. A CT scan identified a heterogeneous mass in the stomach wall.

Lumen-apposing metal stent deployment failure.

Endoscopic ultrasound-guided transmural drainage has become a first-line therapy for pancreatic fluid collections (1). The appearance of lumen-apposing metal stents has resulted in an authentic revolution, due to their efficacy (clinical success rate of 93%) and easy deployment (technical success rate of 98%) (2). They are associated with a shorter procedure time, lower risk of migration and a wider lumen, which could provide a more effective drainage (3). We report the case of a 78-year-old male who developed an infected pancreatic pseudocyst as a late complication of an acalculous severe acute pancreatitis. An endoscopic ultrasound-guided transmural drainage was performed after a failed computed tomography-guided percutaneous drainage with placement of a pig-tail catheter. A gastrocystic fistula was created and an AxiosTM lumen-apposing metal stent (Boston Scientific; Massachusetts, United States) was inserted. Nevertheless, it remained lodged in the pancreatic pseudocyst at the time of deployment. A computed tomography scan confirmed stent placement inside the collection (Figure 1). After endoscopic balloon dilatation of gastrocystic fistulous tract, removal was unsuccessful with proximal traction of the lumen stent flange using biopsy forceps. Surgical treatment was decided and a gastrotomy was performed, the fistula was identified in the posterior gastric wall and the stent was removed. Endoscopic ultrasound-guided transmural drainage of pancreatic fluid collections using lumen-apposing metal stents is a safe procedure. However, it is not exempt of complications such as stent migration, bleeding, gastrointestinal perforation and air embolism (4). Technical failure of lumen-apposing metal stents deployment is a rare complication that may require surgical treatment if endoscopic removal is not possible.

White Matter Stroke Induces a Unique Oligo-Astrocyte Niche That Inhibits Recovery.

Subcortical white matter stroke is a common stroke subtype. White matter stroke stimulates adjacent oligodendrocyte progenitor cells (OPCs) to divide and migrate to the lesion, but stroke OPCs have only a limited differentiation into mature oligodendrocytes. To understand the molecular systems that are active in OPC responses in white matter stroke, OPCs were virally labeled and laser-captured in the region of partial damage adjacent to the infarct in male mice. RNAseq indicates two distinct OPC transcriptomes associated with the proliferative and limited-regeneration phases of OPCs after stroke. Molecular pathways related to nuclear receptor activation, ECM turnover, and lipid biosynthesis are activated during proliferative OPC phases after stroke; inflammatory and growth factor signaling is activated in the later stage of limited OPC differentiation. Within ECM proteins, Matrilin-2 is induced early after stroke and then rapidly downregulated. Prediction of upstream regulators of the OPC stroke transcriptome identifies several candidate molecules, including Inhibin A-a negative regulator of Matrilin-2. Inhibin A is induced in reactive astrocytes after stroke, including in humans. In functional assays, Matrilin-2 induces OPC differentiation, and Inhibin A inhibits OPC Matrilin-2 expression and inhibits OPC differentiation. In vivo, Matrilin-2 promotes motor recovery after white matter stroke, and promotes OPC differentiation and ultrastructural evidence of remyelination. These studies show that white matter stroke induces an initial proliferative and reparative response in OPCs, but this is blocked by a local cellular niche where reactive astrocytes secrete Inhibin A, downregulating Matrilin-2 and blocking myelin repair and recovery.SIGNIFICANCE STATEMENT Stroke in the cerebral white matter of the brain is common. The biology of damage and recovery in this stroke subtype are not well defined. These studies use cell-specific RNA sequencing and gain-of-function studies to show that white matter stroke induces a glial signaling niche, present in both humans and mice, between reactive astrocytes and oligodendrocyte progenitor cells. Astrocyte secretion of Inhibin A and downregulation of oligodendrocyte precursor production of Matrilin-2 limit OPC differentiation, tissue repair, and recovery in this disease.

Bioselection Reveals miR-99b and miR-485 as Enhancers of Adenoviral Oncolysis in Pancreatic Cancer.

Oncolytic viruses are designed for cancer treatment. Cell-virus interactions are key determinants for successful viral replication. Therefore, the extensive reprogramming of gene expression that occurs in tumor cells might create a hurdle for viral propagation. We used a replication-based approach of a microRNA (miRNA) adenoviral library encoding up to 243 human miRNAs as a bioselection strategy to identify miRNAs that facilitate adenoviral oncolytic activity in pancreatic ductal adenocarcinoma. We identify two miRNAs, miR-99b and miR-485, that function as enhancers of adenoviral oncolysis by improving the intra- and extracellular yield of mature virions. An increased adenoviral activity is the consequence of enhanced E1A and late viral protein expression, which is probably mediated by the downregulation of the transcriptional repressors ELF4, MDM2, and KLF8, which we identify as miR-99b or miR-485 target genes. Arming the oncolytic adenovirus ICOVIR15 with miR-99b or miR-485 enhances its fitness and its antitumoral activity. Our results demonstrate the potential of this strategy to improve oncolytic adenovirus potency, and they highlight miR-99b and miR-485 as sensitizers of adenoviral replication.

Mechanisms of demyelination and remyelination in the young and aged brain following white matter stroke.

Subcortical white matter stroke (WMS) accounts for 25% of all incidences of stroke and results in severe motor and cognitive disability. WMS stands as the second leading cause of dementia and is immensely prevalent in older adults. In a startlingly statistic, a majority of human beings will present WMS by 80 years of age. Early ischemic lesions produced by WMS are asymptomatic and termed "silent strokes". WMS is, however, progressive with both the size of the lesions and their distribution, increasing as patients age. Pathological analyses in both postmortem human tissue samples and mouse models of WMS demonstrate myelin degeneration as a chief hallmark of WMS. This suggests that the development of rehabilitative strategies in human WMS will necessitate an understanding of the pathophysiology of demyelination and remyelination following ischemic injury. This review will address our current understanding of WMS from human imaging studies, the development of rodent models of WMS, the mechanistic underpinning of myelin degeneration following WMS as well as remyelination dynamics in the adult brain.

The Masked Polar Group Incorporation (MPGI) Strategy in Drug Design: Effects of Nitrogen Substitutions on Combretastatin and Isocombretastatin Tubulin Inhibitors.

Colchicine site ligands suffer from low aqueous solubility due to the highly hydrophobic nature of the binding site. A new strategy for increasing molecular polarity without exposing polar groups-termed masked polar group incorporation (MPGI)-was devised and applied to nitrogenated combretastatin analogues. Bulky ortho substituents to the pyridine nitrogen hinder it from the hydrophobic pocket while increasing molecular polarity. The resulting analogues show improved aqueous solubilities and highly potent antiproliferative activity against several cancer cell lines of different origin. The more potent compounds showed moderate tubulin polymerization inhibitory activity, arrested the cell cycle of treated cells at the G2/M phase, and subsequently caused apoptotic cell death represented by the cells gathered at the subG0/G1 population after 48 h of treatment. Annexin V/Propidium Iodide (PI) double-positive cells observed after 72 h confirmed the induction of apoptosis. Docking studies suggest binding at the colchicine site of tubulin in a similar way as combretastatin A4, with the polar groups masked by the vicinal substituents. These results validate the proposed strategy for the design of colchicine site ligands and open a new road to increasing the aqueous solubility of ligands binding in apolar environments.

Is prophylactic gastrectomy indicated for healthy carriers of CDH1 gene mutations associated with hereditary diffuse gastric cancer?

INTRODUCTION: hereditary diffuse gastric cancer (HDGC) is a recently reported hereditary cancer syndrome. Patients with suspected HDGC must be under surveillance via endoscopy and multiple biopsies. As an alternative, some studies suggest prophylactic gastrectomy (PG) for disease carriers. The goal of this article was to report our experience with a CDH1 mutation positive family who underwent PG. PATIENTS AND METHODS: the index case was a 34-year-old female diagnosed with diffuse gastric adenocarcinoma and massive carcinomatosis. There was a family history of gastric adenocarcinoma in seven family members. A genetic study identified the c.1577G>A mutation, in exon 11 of the CDH1 gene via sequencing analysis. RESULTS: this mutation was also present in other six family members, who subsequently underwent prophylactic gastrectomy. The pathology study of resected gastric segments revealed multiple microscopic foci of adenocarcinoma in five of these individuals. These foci were not detected in the multiple endoscopies performed before surgery. CONCLUSIONS: we recommend prophylactic gastrectomy for CDH1 mutation carriers even in the absence of lesions during endoscopic screening.

Gluteus maximus contraction velocity assessed by tensiomyography improves following arthroscopic treatment of femoroacetabular impingement.

PURPOSE: Muscular impairment, particularly for the gluteus maximus (GM), has been observed in femoroacetabular impingement (FAI). The purpose of this study was to evaluate the tensiomyographic changes of the GM, rectus femoris (RF) and adductor longus (AL) before and after arthroscopic surgery for FAI. It was hypothesized that arthroscopic treatment of FAI would improve the preoperative muscular impairment. METHODS: All patients undergoing arthroscopic treatment of FAI between January and July 2015 were approached for eligibility. Patients included had a tensiomyography (TMG) evaluation including maximal displacement (Dm) and contraction time (Tc) of these muscles in both lower extremities. TMG values between the injured and healthy sides were compared at the preoperative and post-operative (3, 6 and 12 months after surgery) periods. RESULTS: There were no significant differences for the RF and AL, and Dm of the GM for any of the comparisons (n.s.). However, GM Tc was significantly lower at 3 (p = 0.016), 6 (p = 0.008), and 12 (p = 0.049) months after surgery in the injured side compared to preoperatively. GM Tc of the healthy side was significantly lower than the injured side at the preoperative period (p = 0.004) and at 3 (p = 0.024) and 6 (p = 0.028) months after surgery, but these significant differences were no longer observed at 12 months after surgery (n.s.). There was a significant reduction of pain in the GM area at 1 year after surgery compared to preoperatively (p < 0.0001). CONCLUSIONS: Arthroscopic treatment of FAI and the subsequent rehabilitation improves contraction velocity of the GM of the injured side. Despite Tc is elevated in the GM of the injured compared to the healthy side preoperatively and at 3 and 6 months after surgery, differences in Tc between both sides are no longer significant at 12 months. Athletes with FAI participating in sports with great involvement of GM may benefit from arthroscopic treatment and its subsequent rehabilitation. TMG can be used as an objective measurement to monitor muscular improvements of the GM after surgery in these patients. LEVEL OF EVIDENCE: II.

Clinical and radiographic comparison of a single LP-PRP injection, a single hyaluronic acid injection and daily NSAID administration with a 52-week follow-up: a randomized controlled trial.

BACKGROUND: Knee osteoarthritis (OA) is a disease with a high prevalence in the adult population. Nonsteroidal anti-inflammatory drugs (NSAID) or intra-articular injections [hyaluronic acid (HA) or platelet-rich plasma (PRP)] can provide clinical benefit. Magnetic resonance imaging (MRI) has proven to be useful for the evaluation of cartilage volume and thickness in knee osteoarthritis. The purpose of this study was to evaluate the benefit provided by PRP injection in comparison with hyaluronic acid and NSAID in knee OA patients and to compare the radiographic evolution at the 52-week follow-up. METHODS: One hundred and six patients were enrolled and randomized according to the Spanish Rheumatology Society knee osteoarthritis diagnosis criteria. Ninety-eight patients completed the study (33 received NSAID treatment, 32 a single hyaluronic acid injection and 33 a single PRP injection). Patients were prospectively evaluated at baseline, 26 and 52 weeks using the Western Ontario McMaster Universities osteoarthritis index (WOMAC) and the visual analogue scale (VAS), and at baseline and 52 weeks with X-ray and MRI. RESULTS: A 20% decrease in WOMAC pain and increase in physical function was found in 30 and 24%, respectively, of those patients who received PRP treatment, at the 52-week follow-up. WOMAC pain and VAS improved in the hyaluronic acid and NSAID groups. However, better results were obtained in the PRP group compared to hyaluronic acid and NSAIDs (P < 0.05). No differences in Kellgren-Lawrence or cartilage thickness progression were found. CONCLUSIONS: Leukocyte-poor platelet-rich plasma (LP-PRP) injections are better in terms of clinical improvement with respect to HA injections or oral NSAID treatment in knee osteoarthritis patients at the 52-week follow-up. Moreover, a single LP-PRP injection is effective. However, LP-PRP has no influence on cartilage progression. LEVEL OF EVIDENCE: Level II.

Reassembly of Excitable Domains after CNS Axon Regeneration.

UNLABELLED: Action potential initiation and propagation in myelinated axons require ion channel clustering at axon initial segments (AIS) and nodes of Ranvier. Disruption of these domains after injury impairs nervous system function. Traditionally, injured CNS axons are considered refractory to regeneration, but some recent approaches challenge this view by showing robust long-distance regeneration. However, whether these approaches allow remyelination and promote the reestablishment of AIS and nodes of Ranvier is unknown. Using mouse optic nerve crush as a model for CNS traumatic injury, we performed a detailed analysis of AIS and node disruption after nerve crush. We found significant disruption of AIS and loss of nodes within days of the crush, and complete loss of nodes 1 week after injury. Genetic deletion of the tumor suppressor phosphatase and tensin homolog (Pten) in retinal ganglion cells (RGCs), coupled with stimulation of RGCs by inflammation and cAMP, dramatically enhanced regeneration. With this treatment, we found significant reestablishment of RGC AIS, remyelination, and even reassembly of nodes in regions proximal, within, and distal to the crush site. Remyelination began near the retina, progressed distally, and was confirmed by electron microscopy. Although axons grew rapidly, remyelination and nodal ion channel clustering was much slower. Finally, genetic deletion of ankyrinG from RGCs to block AIS reassembly did not affect axon regeneration, indicating that preservation of neuronal polarity is not required for axon regeneration. Together, our results demonstrate, for the first time, that regenerating CNS axons can be remyelinated and reassemble new AIS and nodes of Ranvier. SIGNIFICANCE STATEMENT: We show, for the first time, that regenerated CNS axons have the capacity to both remyelinate and reassemble the axon initial segments and nodes of Ranvier necessary for rapid and efficient action potential propagation.

Takotsubo cardiomyopathy after cesarean section: A case report and literature review.

Takotsubo cardiomyopathy (TCM) is clinically identical to acute myocardial infarction. We report an unusual case of TCM and review similar cases in pregnant women. A young woman with no pre-existing cardiovascular risk factors suffered sudden dyspnea during a cesarean section. Electrocardiography (ECG) showed T-wave inversion. We observed acute lung edema and left ventricular systolic dysfunction on echocardiography. A cardiac catheterization diagnosed TCM. We reviewed 20 cases of TCM; 17 cases occurred during the post-partum period and three during pregnancy. Five of these cases had vaginal deliveries and the remaining cases had cesarean sections. Within the latter group, five cases appeared intraoperatively. With the exception of one patient with normal ECG results, all other patients progressed, with changes in ECG readings and elevation of cardiac enzyme serum levels. However, cardiac catheterization revealed that coronary arterial damage did not occur in any of the cases. After three months, each patient fully recovered.

Axon initial segment-associated microglia.

Microglia are the brain's resident immune cells and function as the main defense against pathogens or injury. However, in the absence of disease, microglia have other functions in the normal brain. For example, previous studies showed that microglia contribute to circuit refinement and synaptic plasticity in the developing and adult brain, respectively. Thus, microglia actively participate in regulating neuronal excitability and function. Here, we report that in the cortex, but not other brain regions, a subset of microglia extend a single process that specifically associates and overlaps with the axon initial segment (AIS), the site where action potentials are generated. Similar associations were not observed with dendrites or distal axons. Microglia-AIS interactions appear early in development, persist throughout adulthood, and are conserved across species including mice, rats, and primates. However, these interactions are lost after microglial activation following brain injury, suggesting that such interactions may be part of healthy brain function. Loss of microglial CX3CR1 receptors, or the specialized extracellular matrix surrounding the AIS, did not disrupt the interaction. However, loss of AIS proteins by the neuron-specific deletion of the master AIS scaffold AnkyrinG disrupted microglia-AIS interactions. These results reveal a unique population of microglia that specifically interact with the AIS in the adult cortex.

Comparison of tensiomyographic neuromuscular characteristics between muscles of the dominant and non-dominant lower extremity in male soccer players.

PURPOSE: Tensiomyography (TMG) has been used to assess neuromuscular characteristics of muscles of the lower extremity in soccer players. However, the effects of lower extremity dominance on TMG characteristics in this population have not been reported to date. The purpose of this study was to compare the TMG neuromuscular characteristics between the dominant and non-dominant lower extremity in male soccer players. METHODS: Thirty-eight consecutive healthy male soccer players underwent resting TMG assessment of vastus medialis (VM), vastus lateralis (VL), rectus femoris (RF), semitendinosus (ST), biceps femoris (BF), gastrocnemius medialis (GM), and gastrocnemius lateralis (GL) in both lower extremities. The maximal displacement, delay time, contraction time, sustained time, and half-relaxation time were obtained and compared between both sides. RESULTS: There were no significant differences in the vast majority of the TMG parameters between both lower extremities. The dominant side demonstrated higher VM contraction time (p = 0.008), RF sustained time (p = 0.009), RF half-relaxation time (p = 0.01), and BF sustained time (p = 0.04), but lower VL contraction time (p = 0.03) and VL delay time (p = 0.02) compared to the non-dominant side. CONCLUSION: In general, TMG-assessed neuromuscular characteristics of the VM, VL, RF, ST, BF, GM, and GL were not affected by lower extremity dominance in male soccer players. Therefore, there is no need to assess both sides when using TMG to monitor the response to training or muscles at risk of injury in soccer players unless there is a specific reason. LEVEL OF EVIDENCE: Prognostic study, Level II.

Effects of anterior cruciate ligament injury on neuromuscular tensiomyographic characteristics of the lower extremity in competitive male soccer players.

PURPOSE: To investigate the effects of anterior cruciate ligament injury on mechanical and contractile characteristics of the skeletal muscles of the lower extremity in competitive soccer players through tensiomyography (TMG). METHODS: All competitive male soccer players with confirmed acute anterior cruciate ligament tear included underwent resting TMG assessment of muscles of both lower extremities before anterior cruciate ligament reconstruction. The same values were obtained from a sex- and sports level-matched control group. The maximal displacement, delay time, contraction time, sustained time, and half-relaxation time were obtained for the following muscles in all subjects: vastus medialis, vastus laterals, rectus femoris, semitendinosus, biceps femoris, gastrocnemius medialis, and gastrocnemius lateralis. RESULTS: The majority of TMG parameters were higher in the injured compared to the control group. The contraction time of the vastus medialis, vastus lateralis, and rectus femoris was significantly higher in the injured compared to the control group (p = 0.003, p = 0.001, and p < 0.001, respectively). The biceps femoris was the only hamstring muscle with significant differences between groups, with increased contraction time and maximal displacement in the injured compared to the control group (p = 0.002 and p < 0.001, respectively). The gastrocnemius medialis was clearly more affected than the gastrocnemius lateralis, with contraction time, half-relaxation time, and maximal displacement significantly higher (p = 0.01, p = 0.03, and p < 0.001, respectively), and the sustained time significantly lower (p = 0.01), in the injured compared to the control group. The contraction time of the vastus medialis, vastus lateralis, rectus femoris, semitendinosus, and biceps femoris was significantly higher in the injured compared to non-injured side in the anterior cruciate ligament-injured group (p = 0.007, p = 0.04, p = 0.004, p = 0.02, and p = 0.02, respectively). CONCLUSIONS: Anterior cruciate ligament injury caused a decrease in contraction velocity (in quadriceps, hamstrings and gastrocnemius medialis), resistance to fatigue (in quadriceps and gastrocnemius medialis), and muscle tone/stiffness (in hamstrings and gastrocnemius medialis). Overall, it was demonstrated that these effects were worst in the quadriceps and gastrocnemius medialis compared to the hamstring and gastrocnemius lateralis. These findings may contribute to a better design of rehabilitation programs in order to optimize the recovery and potentially increase sport performance at return to sport. LEVEL OF EVIDENCE: Prognostic study, Level II.

Gluteus maximus impairment in femoroacetabular impingement: a tensiomyographic evaluation of a clinical fact.

INTRODUCTION: the aim of the present study is to evaluate the mechanical and contractile properties of the gluteus maximus (GM) muscle in patients with femoroacetabular impingement (FAI). Our hypothesis is that the clinical observation of GM pain would be evidenced by tensiomyographic impairment in muscle function. MATERIALS AND METHODS: A prospective, cross-sectional, intra-group comparative study was conducted to assess the neuromuscular changes of lower extremity muscles in patients with FAI. Fifty-one patients with clinical and radiographic diagnosis of FAI for at least 3 months were included. The rectus femoris (RF), adductor magnus (AM), and GM of both lower extremities of all patients were evaluated with tensiomyography (TMG). The values of TMG of the affected lower extremity were compared to those of the healthy contralateral side. The parameters obtained in this study were maximal displacement (Dm), and contraction time (Tc). RESULTS: The Tc of the injured GM was significantly higher compared to the healthy side (p = 0.01). There were no significant side-to-side differences in the Dm of the GM (p = 0.13), either in the Tc and Dm of the RF (p = 0.15 and p = 0.8, respectively) and AM (p = 0.25 and p = 0.75, respectively). CONCLUSIONS: FAI is associated with impairment of contraction time in the GM of the injured compared to the healthy side. Impairment of the GM may be monitored to evaluate response to conservative or surgical treatment.

Small bowel mesenchymal tumors: description of two unusual cases.

We present two cases of intestinal ileal GIST who developed complications of nonspecific signs and required to be operated urgently, providing unusual images of tumors because of its characteristics.

Effects of anterior cruciate ligament reconstruction on neuromuscular tensiomyographic characteristics of the lower extremity in competitive male soccer players.

PURPOSE: To investigate the effects of anterior cruciate ligament (ACL) reconstruction on mechanical and contractile properties of the skeletal muscles of the lower extremities in soccer players through tensiomyography (TMG). METHODS: All soccer players with acute ACL tear included underwent resting TMG assessment of muscles of both lower extremities before and 1 year after ACL reconstruction. The muscles assessed were vastus medialis (VM), vastus laterals (VL), rectus femoris (RF), semitendinosus (ST), biceps femoris (BF), gastrocnemius medialis (GM), and gastrocnemius lateralis (GL). The TMG parameters obtained for each muscle were maximal displacement (D m), delay time (T d), contraction time (T c), sustained time (T s), and half-relaxation time (T r). RESULTS: The injured leg had a significant decrease in VL-T c, ST-T c, GM-T c, GL-T r, and GL-T d, and a significant increase in VM-T r and GM-T s in the postoperative compared to preoperative period. The non-injured leg demonstrated significant preoperative-postoperative changes in the VL, RF, and BF, but not in VM, ST, GM, and GL The magnitude of preoperative-postoperative differences in the injured leg was significantly higher in RF-T c, ST-T c, BF-D m, and GL-T r, but lower in RF-T r and GM-T s, compared to the non-injured leg. Both groups improved their symmetry between the quadriceps and hamstring muscle groups in both sides. CONCLUSIONS: The quadriceps muscles improved their resistance to fatigue and contraction velocity in both sides, and the hamstring muscles improved their contraction velocity and muscle tone in both sides as well. Improvements in contraction velocity and muscle tone were more evident in the quadriceps and hamstrings of the injured compared to the uninjured side. In addition, the intervention increased the percentage of symmetry between both sides in the TMG of the quadriceps muscles and the balance between ACL-agonist (hamstrings) and ACL-antagonist (quadriceps) muscle groups in both sides. This study shows how ACL reconstruction (and subsequent rehabilitation) can positively impact neuromuscular characteristics of the quadriceps and hamstrings. LEVEL OF EVIDENCE: Therapeutic, Level II.