Vitrification cryopreservation of ligaments based on zwitterionic betaine

Ligament cryopreservation enables a prolonged shelf life of allogeneic ligament grafts,which is fundamentally important to ligament reconstruction.However,conventional cryopreservation techniques fail to eliminate the damage caused by ice crystal growth and the toxicity of cryopreservation agents(CPAs).Here,we report a novel CPA vitrification formulation primarily composed of betaine for ligament cryopreservation.Comprehensive optimization was conducted on the methods for vitrification and rewarming,as well as the loading and unloading conditions,based on the critical cooling rate(CCR),critical warming rate(CWR),and permeation properties of the CPA.Using biomechanical and histological level tests,we demonstrate the superior performance of our method in ligament cryopreservation.After 30 days of vitrification cryopreservation,parameters such as the Young's modulus,tensile stress,denaturation temperature,and glycosaminoglycans content of the ligament remained essentially unchanged.This work pioneers the application of ice-free cryopreservation for ligament and holds great potential for improving the long-term storage of ligament,providing valuable insights for future cryopreservation technique development.

A novel mesenchymal stem cell-targeting dual-miRNA delivery system based on aptamer-functionalized tetrahedral framework nucleic acids:Application to endogenous regeneration of articular cartilage

Articular cartilage injury(ACI)remains one of the key challenges in regenerative medicine,as current treatment strategies do not result in ideal regeneration of hyaline-like cartilage.Enhancing endogenous repair via micro-RNAs(miRNAs)shows promise as a regenerative therapy.miRNA-140 and miRNA-455 are two key and promising candidates for regulating the chondrogenic differentiation of mesenchymal stem cells(MSCs).In this study,we innovatively synthesized a multifunctional tetrahedral framework in which a nucleic acid(tFNA)-based targeting miRNA codelivery system,named A-T-M,was used.With tFNAs as vehicles,miR-140 and miR-455 were connected to and modified on tFNAs,while Apt19S(a DNA aptamer targeting MSCs)was directly integrated into the nanocomplex.The relevant results showed that A-T-M efficiently delivered miR-140 and miR-455 into MSCs and subsequently regulated MSC chondrogenic differentiation through corresponding mechanisms.Interestingly,a synergistic effect between miR-140 and miR-455 was revealed.Furthermore,A-T-M successfully enhanced the endogenous repair capacity of articular cartilage in vivo and effectively inhibited hypertrophic chondrocyte formation.A-T-M provides a new perspective and strategy for the regeneration of articular cartilage,showing strong clinical application value in the future treatment of ACI.

Anatomy of the lateral ligaments of the rectum: A controversial point of view

The existence and composition of the lateral ligaments of the rectum (LLR) are still the subjects of anatomical confusion and surgical misconception up to now. Since Miles proposed abdominoperineal excision as radical surgery for rectal cancer, the identification by "hooking them on the finger" has been accepted by many surgeons with no doubt; clamping, dividing and ligating are considered to be essential procedures in mobilization of the rectum in many surgical textbooks. But in cadaveric studies, many anatomists could not find LLR described by the textbooks, and more and more surgeons also failed to find LLR during the proctectomy according to the principle of total mesorectal excision. The anatomy of LLR has diverse descriptions in literatures. According to our clinical observations, the traditional anatomical structures of LLR do exist; LLR are constant dense connective bundles which are located in either lateral side of the lower part of the rectum, run between rectal visceral fascia and pelvic parietal fascia above the levator ani, and covered by superior fascia of pelvic diaphragm. They are pathways of blood vessels and nerve fibers toward the rectum and lymphatic vessels from the lower rectum toward the iliac lymph nodes.

Serum Metabonomics of Articular Cartilage Destruction Induced by T-2 Toxin in Wistar Rats

The molecular pathogenesis of T-2 toxin-induced cartilage destruction has not been fully unraveled yet. The aim of this study was to detect changes in serum metabolites in a rat anomaly model with articular cartilage destruction. Thirty healthy male Wistar rats were fed a diet containing T-2 toxin （300 ng/kg chow） for 3 months. Histopathological changes in femorotibial cartilage were characterized in terms of chondrocyte degeneration/necrosis and superficial cartilage defect, and the endogenous metabolite profile of serum was determined by UPLC/Q-TOF MS. Treated rats showed extensive areas of chondrocyte necrosis and superficial cartilage defect in the articular cartilage. In addition, 8 metabolites were found to change significantly in these rats compared to the control group, including lyso PE （18：0/0：0）, lyso PC（14：0）, lyso PC[18：4 （6Z,9Z,12Z,15Z）], lyso PC[（16：1（9Z）], lyso PC（16：0）, L-valine, hippuric acid, and asparaginyl-glycine. These 8 metabolites associated with cartilage injury are mainly involved in phospholipid and amino acid metabolic pathways.

A non-linear finite element model of human L4-L5 lumbar spinal segment with three-dimensional solid element ligaments

This paper establishes a non-linear finite element model (NFEM) of L4-L5 lumbar spinal segment with accurate three-dimensional solid ligaments and intervertebral disc. For the purpose, the intervertebral disc and surrounding ligaments are modeled with four-nodal three-dimensional tetrahedral elements with hyper-elastic material properties. Pure moment of 10 N·m without preload is applied to the upper vertebral body under the loading conditions of lateral bending, backward extension, torsion, and forward flexion, respectively. The simulate relationship curves between generalized forces and generalized displacement of the NFEM are compared with the in vitro experimental result curves to verify NFEM. The verified results show that: (1) The range of simulated motion is a good agreement with the in vitro experimental data; (2) The NFEM can more effectively reffect the actual mechanical properties than the FE model using cable and spring elements ligaments; (3) The NFEM can be used as the basis for further research on lumbar degenerative diseases.

Abnormal subchondral bone remodeling and its association with articular cartilage degradation in knees of type 2 diabetes patients

Type 2 diabetes （T2D） is associated with systemic abnormal bone remodeling and bone loss. Meanwhile, abnormal subchondral bone remodeling induces cartilage degradation, resulting in osteoarthritis （OA）. Accordingly, we investigated alterations in subchondral bone remodeling, microstructure and strength in knees from T2D patients and their association with cartilage degradation. Tibial plateaus were collected from knee OA patients undergoing total knee arthroplasty and divided into non-diabetic （n---70） and diabetes （n = 51） groups. Tibial plateaus were also collected from cadaver donors （n = 20） and used as controls. Subchondral bone microstructure was assessed using micro-computed tomography. Bone strength was evaluated by micro-finite-element analysis. Cartilage degradation was estimated using histology. The expression of tartrate-resistant acidic phosphatase （TRAP）, osterix, and osteocalcin were calculated using immunohistochemistry. Osteoarthritis Research Society International （OARSI） scores of lateral tibial plateau did not differ between non-diabetic and diabetes groups, while higher OARSI scores on medial side were detected in diabetes group. Lower bone volume fraction and trabecular number and higher structure model index were found on both sides in diabetes group. These microstructural alterations translated into lower elastic modulus in diabetes group. Moreover, diabetes group had a larger number of TRAP~ osteoclasts and lower number of Osterix~ osteoprogenitors and Osteocalcin~ osteoblasts. T2D knees are characterized by abnormal subchondral bone remodeling and microstructural and mechanical impairments, which were associated with exacerbated cartilage degradation. In regions with intact cartilage the underlying bone still had abnormal remodeling in diabetes group, suggesting that abnormal bone remodeling may contribute to the early pathogenesis of T2D-associated knee OA.

Ligaments disruption:a new perspective in the prognosis of spinal cord injury

The worldwide prevalence of spinal cord injury （SCI） ranges from 233 to 755 per million inhabitants, whereas the report- ed incidence lies between 10.4 and 83 per million inhabitants annually （Wyndaele and Wyndaele, 2006）. Thus, the socio- economic impact of SCI associated with cervical trauma is high enough that it could become an important concern in the vast majority of developed countries.

Three-dimensional finite element analysis of ligaments of lumbar spine

The lumbar ligaments play an important role in spinal biomechanics.The results ofthree-dimensional finite dement analysis showed that one of the functions of lumbar ligaments istransmission of the tensile load between the lumbar vertebrae.The anterior longitudinal ligament isloaded in extension of lumbar spine and the resistance to the tensile load in flexion is providedby other ligaments.These ligaments are subject to much more tension with degeneration of theintervertebral disc so that a series of pathological changes occur.Relevant significance in clinical as-pect is also discussed.

Magnetic resonance imaging of the ligaments of the craniocervical region at 3Tesla magnetic resonance unit: Quantitative and qualitative assessment

Purpose: The assessment of the morphology and dimensions of the craniocervical ligaments using a 3 Tesla (T) Magnetic Resonance (MR) scanner, the correlatation of our results with those from cadaveric and other MR studies and the detection of the most appropriate sequence for the best imaging of the craniovertebral junction ligaments. Methods: 58 healthy volunteers (mean age 45 years) underwent a Magnetic Resonance Imaging (MRI) of the cervical spine at 3T MR unit. The MRI protocol included axial, coronal and sagittal Proton-Density (PD) sequences and sagittal T1 Fluid Attenuated Inversion Recovery (FLAIR) and T2 sequences. The images were evaluated by two radiologists and the posterior atlantoocipital ligament, the anterior atlantoocipital ligament, the transverse ligament and the apical ligament were anatomically detected, described and measured. Results: The transverse ligament was identified at 93.1%, the apical ligament was identified at 60.34%, the posterior at- lantooccipital membrane was identified at 94.8% and the anterior atlantooccipital membrane was identified at 96.5% of the cases. All ligaments appeared with low signal intensity, except the anterior atlantooc-cipital ligament which appeared with intermediate signal intensity. Their length, width and thickness were measured and, in general, correlated well with other anatomic and MR studies. Conclusion: Reliable assessment of the morphology and signal intensity of the craniocervical ligaments can be achieved with PD sequence at 3T MR imaging. The sagittal plane provides better delineation of the craniocervical (CC) ligaments but the axial and coronal planes are of paramount importance in the assessment of the transverse and apical ligaments.

Ligament augmentation reconstruction system artificial ligaments in patellar tendon reconstruction-a chronic patellar tendon rupture after multiple operations: A case report

BACKGROUND Patellar tendon rupture is a rare disease,and reports regarding patellar tendon reconstruction with ligament augmentation reconstruction system(LARS)ligaments are limited,with only three reports available in the literature.LARS ligaments are made of polyethylene terephthalate and have been certified as a more favorable option than other tendon transplants.To our knowledge,this is the first report of patellar tendon reconstruction with LARS for suture fixation due to poor quality of the tendon after multiple operations to enable early mobilization and quick rehabilitation.CASE SUMMARY A 65-year-old woman had limited ability in extending her leg and an inability to perform a straight leg raise after multiple operations due to patella fracture.The patient underwent patellar tendon reconstruction with LARS artificial ligaments.After 12 mo of follow-up,the patient was able to perform a straight leg raise,and the incision healed well without complications.The Lysholmscore was 95 and the range of motion of the knee was 0-130°.CONCLUSION This study revealed that patellar tendon reconstruction with LARS artificial ligaments is possible in a patient with a patellar tendon rupture who required rapid postoperative recovery.

Bilateral papilledema caused by chronic infantile neurological cutaneous and articular syndrome in a child with a novel (p. D305N) mutation in NLRP3 gene: a case report

The rare disease of chronic infantile neurological cutaneous and articular(CINCA)syndrome,is caused by the over-secretion of interleukin(IL)-1βdue to a gain-of-function NLRP3 gene mutation in the autosomal chromosome which often involves in eyes.In this report,we studied a 9-year-old girl with CINCA.The eyes were also involved and presented bilateral papilledema.Genetic testing revealed that the symptoms were caused by a novel gene mutation site(c.913G>A,p.D305N)in conservative domain exon-3 of NLRP3 which is gain-function gene of CINCA.The patient had the characteristic facial features,frontal fossa and saddle nose,manifested the generalized urticaria-like skin rash at two weeks after birth,periodic fever 6 months after birth,sensorineural deafness at 7 years old,and bilateral papilledema,aseptic meningitis and knee arthropathy at 9 years old.White cell counts,C-reactive protein increased and intracranial pressure raised to 300 mmH2O.The meningeal thickening enhanced by gadolinium in magnetic resonance imaging(MRI).Based on clinical features and genetic test,the girl was diagnosed bilateral papilledema secondary to CINCA and administered prednisone and lowered intracranial pressure medicine to resolve symptoms.With 3-year follow-up,patient had no inflammatory flare-up with visual acuity improvement.The finding of novel genetic mutation site(p.D305N)in NLRP3 gene expanded genotype spectrum associated with CINCA.This case also expanded the cause spectrum of papilledema and it highlighted systemic disease history for patients with bilateral papilledema.

Mechanical properties of 65Mn chiral structure with three ligaments

Chiral honeycomb structures have been developed in recent years, showing excellent mechanical properties, including in-plane deformation and out-of-plane bearing and vibration isolation. In this study, the 65Mn chiral structure with three ligaments was modeled and analyzed using the finite element (FE) method. The effects of the dimensionless ligament length and dimensionless ligament thickness on the in-plane equivalent elastic modulus, equivalent Poisson's ratio, and out-of-plane shear modulus were studied. The numerical results indicate that increase of the dimensionless ligament length leads to decrease of the equivalent elastic modulus and increase of the equivalePoisson's ratio, whereas the out-of-plane equivalent shear modulus decreases. The results also indicate that increase of the dimensionless ligament thickness leads to in crease of the equivalent elastic modulus, whereas the equivalent Poisson's ratio remains nearly unchanged and the out-of-plane equivalent shear modulus shows a linear in crease. The numerical results are verified by comparis on with published experime ntal data. These results will provide a reference for the application of chiral structures with three ligaments in the aerospace field.

Optimization of Material Coefficients in the Holzapfel-Gasser-Ogden Material Model for the Main Four Ligaments of the Knee Joint-A Finite Element Study

Accurate representation of soft tissue material properties plays a crucial role in computational biomechanics. Several material models have been used for knee ligaments in finite element (FE) studies, including the neo-Hookean model (widely used) and the Holzapfel-Gasser-Ogden (HGO) model (seldom used). While the coefficients of neo-Hookean models for the knee ligaments are available in the literature, limited data exists for the HGO model. Furthermore, no peer-reviewed comparison of these two material models for the knee ligaments while including the 3D representation of the ligaments for both material models is present in the literature. We used mechanical properties from the tensile test experiments in the literature for each ligament to obtain the HGO material coefficients while accounting for the ligaments’ viscoelastic behavior. Resultant coefficients were then used in an Abaqus/explicit knee model to simulate bipedal landing from a jump. The simulations were repeated with neo-Hookean values from the literature. Knee kinematics plus ACL and MCL strains were evaluated and compared for these two material models. The outputs from the simulations with HGO properties were predominantly within 1.5 standard deviations from the mean in-vitro data. When the material properties changed to Neo-Hookean, the outputs for kinematics and strain values were higher than the HGO case, and in most instances, they were outside the experimental range for ACL and MCL strains (by up to 11.35 SD) as well as some ITR angles (by up to 2.86 SD). Reported HGO material model with optimized coefficients produces a more realistic representation of the ligaments’ material properties, and will help improve the outcomes of FE models for more accurate predictions of knee behavior.

Altered Gene Expression in Articular Chondrocytes of Smad3^(ex8/ex8) Mice, Revealed by Gene Profiling Using Microarrays

It has been previously reported that small mother against decapentaplegic 3 （Smad3） gene knockout （Smad3^ex8/ex8） mice displays phenotypes similar to human osteoarthritis, as characterized by abnormal hypertrophic differentiation of articular chondrocytes. To further clarify the crucial target genes that mediate transformation growth factor-β （TGF-β）/Smad3 signals on articular chondrocytes differentiation and investigate the underlying molecular mechanism of osteoarthritis, microarrays were used to perform comparative transcriptional profiling in the articular cartilage between Smad3^ex8/ex8and wild-type mice on day five after birth. The gene profding results showed that the activity of bone morphogenetic protein （BMP） and TGF-β/cell division cycle 42 （Cdc42） signaling pathways were enhanced in Smad3^ex8/ex8 chondrocytes. Moreover, there was altered gene expression in growth hormone/insulin-like growth factor 1 （Igfl） axis and fibroblast growth factor （Fgf） signaling pathway. Notably, protein synthesis related genes and electron transport chain related genes were upregulated in Smad3^ex8/ex8 chondrocytes, implying that accelerated protein synthesis and enhanced cellular respiration might contribute to hypertrophic differentiation of articular chondrocytes and the pathogenesis of osteoarthritis.

The finite element analysis of articular cartilage fiber-reinforced composite model under rolling load

Articular cartilage is a layer of low-friction,load-bearing soft hydrated tissue covering bone-ends in diarthrosis,which plays an important role in spreading the load,reducing the joint contact stress,joint friction and wear during exercise.The vital mechanical function

Mesenchymal stem cells as a potent cell source for articular cartilage regeneration

Since articular cartilage possesses only a weak capac-ity for repair, its regeneration potential is considered one of the most important challenges for orthopedic surgeons. The treatment options, such as marrow stimulation techniques, fail to induce a repair tissue with the same functional and mechanical properties of native hyaline cartilage. Osteochondral transplantation is considered an effective treatment option but is as-sociated with some disadvantages, including donor-site morbidity, tissue supply limitation, unsuitable mechani-cal properties and thickness of the obtained tissue. Although autologous chondrocyte implantation results in reasonable repair, it requires a two-step surgical pro-cedure. Moreover, chondrocytes expanded in culture gradually undergo dedifferentiation, so lose morpho-logical features and specialized functions. In the search for alternative cells, scientists have found mesenchymal stem cells(MSCs) to be an appropriate cellular mate-rial for articular cartilage repair. These cells were origi-nally isolated from bone marrow samples and further investigations have revealed the presence of the cells in many other tissues. Furthermore, chondrogenic dif-ferentiation is an inherent property of MSCs noticedat the time of the cell discovery. MSCs are known to exhibit homing potential to the damaged site at which they differentiate into the tissue cells or secrete a wide spectrum of bioactive factors with regenerative proper-ties. Moreover, these cells possess a considerable im-munomodulatory potential that make them the general donor for therapeutic applications. All of these topics will be discussed in this review.

Benefits of Ilizarov automated bone distraction for nerves and articular cartilage in experimental leg lengthening

AIM To determine peculiarities of tissue responses to manual and automated Ilizarov bone distraction in nerves and articular cartilage.METHODS Twenty-nine dogs were divided in two experimental groups: Group M-leg lengthening with manual distraction(1 mm/d in 4 steps), Group A-automated distraction(1 mm/d in 60 steps) and intact group. Animals were euthanized at the end of distraction, at 30 th day of fixation in apparatus and 30 d after the fixator removal. M-responses in gastrocnemius and tibialis anterior muscles were recorded, numerical histology of peronealand tibialis nerves and knee cartilage semi-thin sections, scanning electron microscopy and X-ray electron probe microanalysis were performed.RESULTS Better restoration of M-response amplitudes in leg muscles was noted in A-group. Fibrosis of epineurium with adipocytes loss in peroneal nerve, subperineurial edema and fibrosis of endoneurium in some fascicles of both nerves were noted only in M-group, shares of nerve fibers with atrophic and degenerative changes were bigger in M-group than in A-group. At the end of experiment morphometric parameters of nerve fibers in peroneal nerve were comparable with intact nerve only in A-group. Quantitative parameters of articular cartilage(thickness, volumetric densities of chondrocytes, percentages of isogenic clusters and empty cellular lacunas, contents of sulfur and calcium) were badly changed in M-group and less changed in A-group.CONCLUSION Automated Ilizarov distraction is more safe method of orthopedic leg lengthening than manual distraction in points of nervous fibers survival and articular cartilage arthrotic changes.

A new method for computing the uniaxial modulus of articular cartilages using modified inhomogeneous triphasic model

It is well known that subtle changes in structure and tissue composition of articular cartilage can lead to its degeneration. The present paper puts forward a modified layered inhomogeneous triphasic model with four parameters based on the inhomogeneous triphasic model proposed by Narmoneva et al. Incorporating a piecewise fitting optimization criterion, the new model was used to obtain the uniaxial modulus Ha, and predict swelling pattern for the articular cartilage based on ultrasound-measured swelling strain data. The results show that the new method can be used to provide more accurate estimation on the uniaxial modulus than the inhomogeneous triphasic model with three parameters and the homogeneous mode, and predict effectively the swell- ing strains of highly nonuniform distribution of degenerated articular cartilages. This study can provide supplementary information for exploring mechanical and material properties of the cartilage, and thus be helpful for the diagnosis of osteoarthritis-related diseases.