Tissue Failure Research Articles

Poster 254: Mechanical Response of ACL to Submaximal Fatigue Loading

Poster 254: Mechanical Response of ACL to Submaximal Fatigue Loading

Effect of epitendinous suture augmentation to a double Krackow suture pattern for canine gastrocnemius tendon repair.

To evaluate the effect of a double Krackow suture pattern (DK), with and without epitendinous suture augmentation (ES), in a canine gastrocnemius tendon (GT) model. Paired GTs from 12 adult dog cadavers and 4 control GT. GTs were assigned to 2 groups (n = 12/group). Transverse tenotomy was performed and repaired with a DK or DK + ES. Yield, peak, and failure force, stiffness, occurrence of 1-and 3-mm gapping, and failure mode were examined. Yield, peak, and failure loads were greater for DK + ES. Yield force was 48% greater for DK + ES (mean ± SD, 149.56 ± 53.26 N) versus DK (101.27 ± 37.17 N; P = 0.017). Peak force was 45% greater for DK + ES P < 0.001). Failure force was 47% greater for DK + ES (193.752 ± 31.43 N) versus DK (131.54 ± 22.28 N; P < 0.001). Construct stiffness was 36% greater for DK + ES (P = 0.04). All 12 DK and 10 of 12 DK + ES repairs produced a 1-mm gap, with all DK and 4 DK + ES repairs producing a 3-mm gap (P < 0.001). Loads required to create a 3-mm gap were significantly greater for DK + ES (P < 0.013). Suture breakage occurred in all DK repairs, which differed from DK + ES, where suture breakage (7/12) and tissue failure (5/12; P = 0.037) predominated. Augmentation of a primary DK repair with an ES significantly improved construct strength in canine GT constructs while increasing loads required to cause 1- and 3-mm gap formation, respectively. ES augmentation is a simple technique modification that can be used to significantly increase construct strength, compared with DK alone.

An evaluation of fiber-based damage for assessing the failure of aortic tissue: comparison between healthy and aneurysmal aortas

The decision of surgical intervention for an aortic aneurysm is usually associated with an assessment of risk of its rupture. Global rupture risk assessment parameters like wall diameter and growth of the aneurysm over time often fail at predicting the risk of rupture with accuracy. This paper will investigate the hypothesis that the tissue’s microstructure determines its macroscopic failure. To this aim, two different testing protocols have been implemented. Human ascending thoracic aortic aneurysm (ATAA) tissue samples were subjected to bulge-inflation testing until rupture coupled with multi-photon microscopy (MPM) imaging. Image stacks of the sample were acquired at different pressure levels. Additionally, porcine aorta samples were tested under uniaxial tension until failure and their response was recorded. Prior to mechanical testing, MPM image stacks were acquired at four different zones on the sample. The image stacks acquired at the load free state were used to extract morphological information relating to collagen fibers. Then, an inverse random sampling approach was used to generate pseudomorphological parameters for network reconstruction. A discrete model of the collagen network signifying its stochastic nature was then developed, including both prefailure and post-failure mechanics. The model was able to replicate the mechanical response and failure of the tissue, and demonstrated that fiber-based damage can strongly shape the macroscopic failure response of the tissue. Identified values of collagen fiber failure strain were in the range of 8.8 to 29.3% in the case of aneurysmal samples, and 18.7 to 25.5% in the case of porcine samples. A statistical analysis enabled the characterization of correlation between fiber morphology and tissue failure. The model may serve as a useful tool for predicting macroscale failure of the aortic wall based on the variations in microscale morphology.

A Brief Overview to Ageing-Related Organ Damage: A Light and Electron Microscopic Approach to Several Systems

Ageing is thought to be a degenerative process caused by accumulated damage leading to cellular dysfunction, tissue, and organ failure, and eventually death. Although aging-related skin changes are considered the most important indicator of ageing, morphological and functional changes occur in all of the internal organs. Most of those changes are directly or indirectly associated with age-related decline of life quality. Histopathological features of the organs of old people are examined in postmortem tissues which are probably affected by diseases alongside ageing itself. Recent studies principally report the cellular changes obtained from rodents. The most commonly reported ageing-related ultrastructural changes are mitochondrial damage, lysosome and lipofuscin accumulation and dilatation or proliferation of endoplasmic reticulum. Here I summarize ageing-related changes in various organs such as skin, brain, heart, kidney, intestines etc. that have been revealed by light and electron microscopic examinations so far. Understanding ageing-related cell and tissue-based changes and related molecular mechanisms will contribute to the development of new strategies to prevent or eliminate age-related organ damage.

Constitutive modeling of the mechanical response of arterial tissues

Despite the tremendous impact that a good constitutive relation for the response of arterial tissues can have with regard to advances in cardiovascular science and medicine, and notwithstanding the intense effort to put a felicitous constitutive relation into place, no reliable constitutive relation is available in the literature. In this review article, we provide a brief survey and assessment of the evolution of constitutive relations that have been developed to describe the response of arterial tissues, their inadequacies, and the various quintessential aspects of the response that need to be taken into consideration. We then fashion a nonlinear constitutive relation to describe an inhomogeneous anisotropic compressible viscoelastic solid, which while being grossly inadequate to describe the tissue in its entirety, makes it evident that what one ought to strive for is not in capturing the complexity of tissues, but rather the development of a simple global measure that can be a reliable predictor of the onset of tissue disease, and tissue damage and failure.

Physiologic Transdermal Estradiol Replacement Mimics Effects of Endogenous Estrogen on Bone Outcomes in Hypoestrogenic Women with Anorexia Nervosa.

Background: While physiologic estrogen replacement results in increases in areal bone mineral density (aBMD) in hypoestrogenic adolescent girls and young adult women with AN, data are lacking regarding its impact on measures of volumetric BMD (vBMD), bone geometry, and structure. Methods: 23 young women with anorexia nervosa (AN) and 27 normal-weight healthy controls (HC) between 14–25 years old were followed for 12 months. AN participants received transdermal 17β-estradiol (continuously) with 10 days of cyclic oral progesterone (100 mg daily) every month for the study duration (AN-E+). DXA was used to measure aBMD and body composition, high resolution peripheral quantitative CT (HRpQCT) to assess vBMD, bone geometry and structure at the distal radius and tibia, and microfinite element analysis to estimate strength. Results: Groups did not differ for age. Median baseline BMI z-scores were −1.13 (−1.58, −0.38) in AN-E+ vs. 0.08 (−0.40, 0.84) in HC (p < 0.0001). For most HRpQCT parameters and strength estimates, young women with AN receiving physiologic estrogen replacement demonstrated similar changes over 12 months as did normoestrogenic HC. Additionally, radial cortical tissue mineral density, cortical vBMD, and failure load increased (p = 0.01; p = 0.02; p = 0.004 respectively) over 12 months in AN-E+ compared to HC. Conclusions: With physiologic estrogen replacement, bone accrual improved in AN to approximate changes observed in normoestrogenic controls followed without any intervention, with additional benefits observed for cortical tissue mineral density, cortical vBMD, and failure load at the radius in AN vs. controls. Thus, this strategy for estrogen replacement effectively mimics the effects of endogenous estrogen on bone structure and estimated strength.

Arthroscopic Posterior Capsulolabral Reconstruction With Gracilis Allograft

Posterior shoulder instability is increasingly recognized and represents a complex continuum of pathology that can be challenging to diagnose and treat. Current surgical options involve posterior labral repair with or without capsular plication, as well as bony procedures, including glenoid bone grafting and glenoid osteotomy when indicated, often in the setting of revision. There is presently a dearth of surgical options to directly address the root cause of soft tissue failure, including a diminutive posterior labrum, chondrolabral retroversion, and thin or hyperelastic posterior capsule. This article presents a technique for arthroscopically augmenting the posterior capsulolabral complex in the setting of soft tissue insufficiency, laxity, or poor prognostic factors for failure. Secondarily, this technique provides a lower risk revision option for reconstruction in failed posterior instability without glenoid bone defect.

Nesfatin-1 - as a diagnosis regulatory peptide in type 2 diabetes mellitus.

One of the most common metabolic diseases, Type 2 Diabetes Mellitus (T2DM), is caused by a combination of two basic factors: insufficient insulin secretion by pancreatic -cells or a failure of insulin-sensitive tissues to respond adequately to insulin. The aim of this paper was to assess the diagnostic accuracy of serum nesfatin-1 in type 2 diabetes mellitus (T2DM). Sixty patients with T2DM were recruited from (Baquba Teaching Hospital) in Iraq during the period (from November 2021 - March 2022). T2DM group was classified into 30 newly diagnosis patients (without treatment) and 30 ongoing diabetic patients (with treatment) for comparison, as well 30 healthy individuals were included as a control. The ELISA Kit was used to measure serum nesfatin-1 and serum insulin, fasting serum glucose, and lipid profile test were measured through spectrophotometric, instead of HbA1c was determined using HPLC method. The concentration of serum nesfatin-1 in the T2DM group was significantly lower than that of the healthy subjects (p < 0.05). There was a significant difference in the serum nestafin-1 concentrations between newly diagnosis and ongoing T2DM patients. There were substantial negative connections between serum Nesfatin-1 concentration and HOMA-IR, as well as strong negative correlations between serum nesfatin-1 and serum insulin level. The concentration of serum Nesfatin-1, on the other hand, had no significant association with the anthropometries measurements and biochemical parameters. The area under the curve was excellent (AUC = 0.827, p = 0.0001), with high diagnostic accuracy (86.2) in differentiating newly diagnosis T2DM from the healthy subject group. Nesfatin-1 levels in the sera of diabetic patients was shown to be lower and nesfatin-1 levels were shown to be significantly linked to newly diagnosed patients.

Impact of First Metatarsal Hyperpronation on First Ray Alignment: A Study in Cadavers.

There is increased evidence of first metatarsal hyperpronation in patients with hallux valgus, but its impact on the stability of the first metatarsophalangeal and metatarsosesamoid joints is unknown. A previous biomechanical study showed that an increase in hallucal pronation might lead to medial soft tissue failure of the first metatarsophalangeal joint. Conversely, dynamic studies on hallux valgus have shown that the first tarsometatarsal joint moves in supination during weightbearing, and supination was associated with an increase in the intermetatarsal angle (IMA) and hallux valgus angle (HVA). (1) Does an increase in first metatarsal pronation cause an increase in hallucal pronation? (2) Can an intrinsic increase in first metatarsal pronation lead to first ray supination during weightbearing? (3) Can a combination of intrinsic first metatarsal hyperpronation and first metatarsophalangeal medial soft tissue failure increase supination of the first ray during weightbearing? (4) Is first ray supination during weightbearing associated with an increase in the IMA and HVA? Twelve transtibial, nonpaired cadaver specimens without deformities were used. Each specimen underwent six weightbearing CT scans under different conditions. The first three CT examinations were performed without any osteotomy of the first metatarsal. The first was a simulated nonweightbearing condition. The second was a simulated weightbearing condition. The third was a simulated weightbearing condition with medial soft tissue release. Subsequentially, a 30° pronation osteotomy of the first metatarsal was performed, and the same sequence of weightbearing CT images was obtained. On each weightbearing CT image, the HVA, IMA, sesamoid rotation angle, metatarsal pronation angle (MPA), metatarsosesamoid rotation angle, and hallucal pronation (HP) were measured. Motions were calculated based on the differential values of these angular measurements produced by the six different conditions (weightbearing, medial soft tissue release, 30° pronation osteotomy, and combinations of these conditions). We compared means using a t-test for normally distributed variables and the Mann-Whitney U test for nonnormally distributed variables. Correlations were assessed with Pearson product-moment correlation coefficients. We found that 30° pronation osteotomy of the first metatarsal increased the MPA and HP by 28° ± 4° and 26° ± 6°, respectively, in the nonweightbearing condition. No differences between the increase in MPA and the increase in HP were noted (mean difference 2° [95% CI -1° to 5°]; p = 0.20). Therefore, an increase in first metatarsal pronation caused an increase in hallucal pronation. When a 30° pronation osteotomy of the first metatarsal was performed, the first ray motion during weightbearing went from pronation to supination (4° ± 2° in pronation without osteotomy versus 4° ± 2° in supination after the osteotomy, mean difference 8° [95% CI 6° to 9°]; p < 0.001). Therefore, an intrinsic increase in pronation of the first metatarsal led to a first ray supination motion during weightbearing. When a first metatarsophalangeal medial soft tissue release was performed in addition to the 30° osteotomy of the first metatarsal, the supination motion of the first ray increased (4° ± 2° without medial soft tissue release versus 11° ± 7° after the release, mean difference 8° [95% CI 3° to 12°]; p = 0.003). Therefore, a combination of intrinsic first metatarsal hyperpronation and first metatarsophalangeal medial soft tissue failure increased supination of the first ray during weightbearing. Regarding static angular measurements, the HVA and IMA were not correlated with the MPA (ρ = 0.20; p = 0.09 and ρ = 0.22; p = 0.07, respectively). Regarding motions, as the HVA and IMA increased from nonweightbearing to weightbearing the pronation decreased, with strong correlations (ρ = -0.82; p < 0.001 and ρ = -0.77; p < 0.001, respectively). Therefore, a first ray supination during weightbearing was associated with an increase in the HVA and IMA. The combination of first metatarsal intrinsic hyperpronation and first metatarsophalangeal medial soft tissue failure led to a hallux valgus deformity in this cadaveric study. The static measurement of first metatarsal head pronation relative to the ground (MPA) did not reflect the real intrinsic pronation of the first ray, and foot and ankle specialists should be careful when interpreting these measurements. Hallux valgus is a dynamic condition, and the deformity could be more correlated with motions during weightbearing than with plain static measurements. First ray supination compensating for first metatarsal intrinsic hyperpronation might be an important factor in the hallux valgus pathogenesis. Further in vivo studies involving nonweightbearing and weightbearing comparative assessments of hallux valgus and controls should be performed to confirm this pathomechanism.

From Soft to Hard Biomimetic Materials: Tuning Micro/Nano-Architecture of Scaffolds for Tissue Regeneration.

Failure of tissues and organs resulting from degenerative diseases or trauma has caused huge economic and health concerns around the world. Tissue engineering represents the only possibility to revert this scenario owing to its potential to regenerate or replace damaged tissues and organs. In a regeneration strategy, biomaterials play a key role promoting new tissue formation by providing adequate space for cell accommodation and appropriate biochemical and biophysical cues to support cell proliferation and differentiation. Among other physical cues, the architectural features of the biomaterial as a kind of instructive stimuli can influence cellular behaviors and guide cells towards a specific tissue organization. Thus, the optimization of biomaterial micro/nano architecture, through different manufacturing techniques, is a crucial strategy for a successful regenerative therapy. Over the last decades, many micro/nanostructured biomaterials have been developed to mimic the defined structure of ECM of various soft and hard tissues. This review intends to provide an overview of the relevant studies on micro/nanostructured scaffolds created for soft and hard tissue regeneration and highlights their biological effects, with a particular focus on striated muscle, cartilage, and bone tissue engineering applications.

Tissue-engineered collagenous fibrous cap models to systematically elucidate atherosclerotic plaque rupture

A significant amount of vascular thrombotic events are associated with rupture of the fibrous cap that overlie atherosclerotic plaques. Cap rupture is however difficult to predict due to the heterogenous composition of the plaque, unknown material properties, and the stochastic nature of the event. Here, we aim to create tissue engineered human fibrous cap models with a variable but controllable collagen composition, suitable for mechanical testing, to scrutinize the reciprocal relationships between composition and mechanical properties. Myofibroblasts were cultured in 1 × 1.5 cm-sized fibrin-based constrained gels for 21 days according to established (dynamic) culture protocols (i.e. static, intermittent or continuous loading) to vary collagen composition (e.g. amount, type and organization). At day 7, a soft 2 mm ∅ fibrin inclusion was introduced in the centre of each tissue to mimic the soft lipid core, simulating the heterogeneity of a plaque. Results demonstrate reproducible collagenous tissues, that mimic the bulk mechanical properties of human caps and vary in collagen composition due to the presence of a successfully integrated soft inclusion and the culture protocol applied. The models can be deployed to assess tissue mechanics, evolution and failure of fibrous caps or complex heterogeneous tissues in general.

3D Tissue Constructs from the Ground Up for Game Changing New Applications in Tissue Engineering and Regenerative Medicine

In view of the very expensive modern healthcare system, sudden loss or failure of organs and tissues could pose a very difficult and costly medical problem to patients. Further, the limited supply of organs globally that a patient can afford for replacement in the event of an organ failure makes the problem even more challenging and complicated. These medical and healthcare challenges have triggered research and developments into tissue engineering to advance the field of regenerative medicine. Especially, the research focus has been on the design, development and optimization of a cell-scaffold-microenvironment to promote the regeneration of various types of tissue including skin, cartilage, bone, tendon and cardiac tissue, to name a few. Studies have been undertaken to produce functional three-dimensional (3D) tissue substitutes or constructs that are based on bio scaffolds from the ground up. To this end, bioprinting strategies have been considered for fabrication of complex 3D functional living tissues or artificial organs. Here, we describe some notable advances in laser bioprinting enabled tissue engineering, which is a rapidly emerging field in 3D bio fabrication technology for applications in regenerative medicine.

Research advances on stem cell therapy for diabetic foot wounds

Diabetic foot wound repair is a challenging issue in clinical practice. Due to the influence of multiple factors including the damage and regeneration failure of local tissue, the impaired pathways of wound repairing through blood vessels and nerve nutrition, and disorders of a variety of cellular factors, traditional treatment methods are often difficult to achieve good therapeutic effects. Stem cells are a type of cells with potentials of multidirectional differentiation, which also possess functions such as regulating immunity and paracrine to facilitate the comprehensive wound repair, so they have promising application prospect at present for the treatment of diabetic foot wounds. Because the relevant parameters of stem cell treatment are in the exploratory phase, there were no standardized data. This paper reviews the application of stem cells in the research of diabetic foot wound treatment over the past 6 years, analyzing and summarizing the contents in focused aspects including the types and sources of stem cells, effects of donor age and gender on stem cells, mode of administration, transplantation survival rate and safety, which may provide a reference for further application of stem cells in the clinical treatment of diabetic foot wound.

The effect of PRP-therapy on the development of impaired bile excretion under the influence of mechanical damage to the skin, skeletal trauma complicated by acute blood loss, and combined trauma

Introduction. Traumatism is considered to be one of the most topical problems. Its structure is predominated by multiple and combined traumas, which lead to organ and tissue failure remote from the site of the initial trauma. Mechanical damage to the skin is frequently experienced by victims as the result of increase in the number of traffic accidents and combat injuries. However, the hepatic function in the presence of mechanical skin damage is insufficiently studied. There is a paucity of scientific evidence attesting to the efficacy of platelet-rich plasma grafts (PRP - therapy), which play an important role in promoting the healing processes of damaged body tissues.&#x0D; Objective: to establish the effect of PRP-therapy on the development of impaired bile excretion under the influence of mechanical damage to the skin, skeletal trauma complicated by acute blood loss and combined trauma.&#x0D; Materials and methods. The experimental studies were conducted on 126 nonlinear white male rats weighing 180-200 g, which were divided into five groups: the control and four experimental ones. The control group consisted solely of the intact animals exposed to general anesthesia. In the first experimental group, the animals were simulated a mechanical damage to the skin, the rats of the second experimental group were subjected to a skeletal trauma complicated by acute blood loss, the third experimental group had both these lesions combined. In the fourth experimental group, the PRP-therapy was applied using allogeneic platelet-rich plasma injections to the animals with combined trauma. After 3, 7, 14, 21 and 28 days of the posttraumatic period, the common bile duct was catheterized in the control and experimental groups, the bile was collected and the rate of bile excretion was determined.&#x0D; The results and discussion. The conducted studies have evidenced that mechanical damage to the skin, skeletal trauma complicated by acute blood loss, and the combined trauma model were accompanied by a significant decrease in bile excretion rate, indicating the development of secondary liver failure and the deduced functional capacity of the liver. Consequently, the isolated damage to skin has systemic effects on the body and can aggravate impairments caused by skeletal trauma complicated by acute blood loss. The administration of the PRP-therapy injections to rats with combined trauma model resulted in less severe impairments of bile excretion compared to the animals without corrective medication, which was particularly noticeable in late manifestations of traumatic disease after 21 and 28 days. Hence, the PRP-therapy appears to be a promising medication in the presence of combined trauma in terms of decreasing the risk associated with the development of multiple organ failure, which substantiates the pertinence of further depth-in study.&#x0D; Conclusions. Mechanical damage to the skin results in an impaired hepatic function in rats, which is manifested by a diminished bile flow. An additional infliction of mechanical damage to the skin in the presence of skeletal trauma complicated by acute blood loss exacerbates the impairment of bile excretion with a maximum of abnormalities occurred after 7 and 21 days of the posttraumatic period. The administration of the PRP-therapy injections in the background of combined trauma model is accompanied by less abnormal rate of bile excretion, which is statistically significant after 21 and 28 days of the experimental period, as compared to the animals without corrective medication.

Inherited connective tissue diseases highlight macromolecular network interdependences in skin extracellular matrix: a histomorphometric study

ABSTRACT Mutation of just a single extracellular matrix protein, a receptor or enzyme involved in connective tissue metabolism is sufficient to cause systemic pathologies and failure of tissues that are subjected to strong mechanical stresses. Skin histological and computerized image analyses can provide a good qualitative and quantitative indication of these inherited connective tissue diseases. In this study, skin biopsies from young (10 to 25 years) and middle-aged patients (26 to 50 years) suffering from Ehlers-Danlos syndromes (EDS), Marfan syndrome (MS) or pseudoxanthoma elasticum (PXE) were studied after specific staining of both the collagen and elastic networks. Findings from the histomorphometric analyses conducted on skin sections of the patients with EDS, MS and PXE were compared to skin sections of healthy subjects from the same age groups. Our results show that both the collagen and the elastic networks were affected in all the studied pathological cases, but that the adverse changes to the elastic network in older patients were distinct from the physiological changes observed during aging process for healthy subjects. This degenerative process may be explained by an added phenomenon involving a general connective tissue proteolysis.

Strain Response in the Facet Joint Capsule During Physiological Joint Rotation and Translation Following a Simulated Impact Exposure: An In Vitro Porcine Model.

Low back pain (LBP) is frequently reported following rear impact collisions. Knowledge of how the facet joint capsule (FJC) mechanically behaves before and after rear impact collisions may help explain LBP development despite negative radiographic evidence of gross tissue failure. This study quantified the Green strain tensor in the facet joint capsule during rotation and translation range-of-motion tests completed before and following an in vitro simulation of a rear impact collision. Eight FSUs (4 C3-C4, 4 C5-C6) were tested. Following a preload test, FSUs were flexed and extended at 0.5 deg/s until an ±8 N·m moment was achieved. Anterior and posterior joint translation was then applied at 0.2 mm/s until a target ±400 N shear load was imposed. Markers were drawn on the facet capsule surface and their coordinates were tracked during pre- and postimpact range-of-motion tests. Strain was defined as the change in point configuration relative to the determined neutral joint posture. There were no significant differences (p > 0.05) observed in all calculated FJC strain components in rotation and translation before and after the simulated impact. Our results suggest that LBP development resulting from the initiation of strain-induced mechanoreceptors and nociceptors with the facet joint capsule is unlikely following a severe rear impact collision within the boundaries of physiological joint motion.

Hemolytic uremic syndrome associated with Streptococcus pneumoniae

Hemolytic uremic syndrome associated with Streptococcus pneumoniae is a rare disease that occurs in 5-10% of all cases of hemolytic uremic syndromes in childhood. Pneumonia and meningitis are among the main diseases that can be complicated by St. pneumoniae-associated hemolytic uremic syndrome. The widespread introduction of polymerase chain reaction into clinical practice has increased the frequency of detection of this pathology. The article presents the epidemiology, clinical picture, features of pathogenesis, diagnosis and treatment of St. pneumoniae-associated hemolytic uremic syndrome. The authors described 3 clinical cases of this syndrome in children with pneumonia. In 2 patients, pneumonia proceeded with destruction of lung tissue, pleural empyema, bacteremia, and severe renal failure, which required hemofiltration therapy to replace renal function. Outcomes of hemolytic uremic syndrome associated with St. pneumoniae is worse than in typical hemolytic uremic syndrome, and is associated with the severity of the underlying disease (pneumonia, meningitis).

Fifth metatarsal fractures: an update on management, complications, and outcomes

Even though fifth metatarsal fractures represent one of the most common injuries of the lower limb, there is no consensus regarding their classification and treatment, while the term ‘Jones’ fracture has been used inconsistently in the literature.In the vast majority of patients, Zone 1 fractures are treated non-operatively with good outcomes.Treatment of Zone 2 and 3 fractures remains controversial and should be individualized according to the patient’s needs and the ‘personality’ of the fracture.If treated operatively, anatomic reduction and intramedullary fixation with a single screw, with or without biologic augmentation, remains the ‘gold standard’ of management; recent reports however report good outcomes with open reduction and internal fixation with specifically designed plating systems.Common surgical complications include hardware failure or irritation of the soft tissues, refracture, non-union, sural nerve injury, and chronic pain.Patients should be informed of the different treatment options and be part of the decision process, especially where time for recovery and returning to previous activities is of essence, such as in the case of high-performance, elite athletes.

Fabrication of oxidized sodium alginate-collagen heterogeneous bilayer barrier membrane with osteogenesis-promoting ability

Guided bone regeneration technique is an effective approach to repair bone defects, in which a barrier membrane is essential. However, the collagen barrier membranes commonly used lose stability quickly, leading to connective tissue invasion and failure of osteogenesis. Herein, we presented an oxidized sodium alginate (OSA)-collagen heterogeneous bilayer barrier membrane with well-controlled pore size and osteogenesis-promoting ability. The OSA crosslinking significantly improved the structural stability, compressive strength, swelling behavior, and slowed down the biodegradation rate of collagen membranes. Meanwhile, the collagen-based membranes exhibited superior cytocompatibility, osteogenesis-promotion, and barrier function against fibroblasts. Especially, the osteogenic differentiation was most promoted on the membrane with a large pore size (240–310 μm), while the barrier function was most improved on the membrane with a small pore size (30–60 μm). Then the above two membranes were combined together to obtain a heterogeneous bilayer membrane. This bilayer barrier membrane showed excellent osteogenesis-promoting ability in rats.

FEATURES AND STRATEGIES FOR SCAFFOLD DESIGN AND PRODUCTION FOR TISSUE ENGINEERING

Failure or loss of human tissues and organs due to illness or injury requires the partial or even total transplantation. Although transplantation is a successful intervention, donor availability and immune rejections represent still the main drawbacks. In addition, the fast and proper recovery of the patient is nowadays more than necessary to prevent infection, chronic inflammation, and other complications during the tissue/organ healing process. There is still a tremendous interest of alternatives to transplantation, such as scaffold-based tissue engineering, that may contribute to practical outcomes for the worldwide health concern related to severe tissue injuries. Herein, we explore the features, benefits and scaffold designs applied for biotechnological sciences, particularly for tissue engineering. The great potential to transform biocompatible polymers in three-dimensional matrix, assimilating the extracellular matrix (ECM), makes them attractive for cells adhesion and proliferation. On the basic of relevant results recently reported in the literature, along with the pioneering works, we discuss specific issues and challenges such as matrix-cell interactions, strategies to design scaffolds with homogeneous nano/microscales using different techniques, e.g., hydrogels, electrospinning, and rotary jet spinning, as well as the combination of some of these techniques.