Growth-related structural, biochemical, and mechanical properties of the functional bone-cartilage unit

Fixation of an Osteochondral Lesion of the Femoral Intercondylar Groove Using Autogenous Osteochondral Grafts and Bioabsorbable Pins in a Patient with Open Physes: A Case Report

Osteochondral lesion (OCL) of the patellofemoral (PF) joint is not an uncommon cause of knee pain, and surgery is needed when conservative treatment fails. However, there is a lack of evidence regarding the optimal surgical treatment for OCL of the PF joint. Fixation of OCLs using autogenous osteochondral grafts has been reported to be effective for OCL of the knee. However, in this surgical technique, the biomechanical strength of osteochondral grafts may not be sufficient in patients with open physes due to the specific quality of the cartilage and subchondral bone given their age. There is a lack of studies reporting fixation of the OCL located in the PF joint using autogenous osteochondral grafts. We herein report a case of OCL of the femoral intercondylar groove where autogenous osteochondral grafts augmented with bioabsorbable pins were used to fix the lesion in a 14-year-old patient with open physes. Preoperative MRI revealed a completely detached OCL of the intercondylar groove (36 mm × 20 mm). Although a total of four osteochondral grafts were harvested from the non-weightbearing area of the lateral femoral condyle, cartilage detached from one of the grafts. The quality of the osteochondral grafts was considered to be insufficient for stabilization of the OCL; thus, two bioabsorbable pins were additionally inserted following fixation of the lesion using three osteochondral grafts. After two years of follow-up, postoperative functional scores were favorable without knee pain. The present case suggests that fixation of the OCL using autogenous osteochondral grafts may not be appropriate for young patients with open physes.

Ontogenetic Patterning of Human Subchondral Bone Microarchitecture in the Proximal Tibia

High-resolution computed tomography images were acquired for 31 proximal human tibiae, age 8 to 37.5 years, from Norris Farms #36 cemetery site (A.D. 1300). Morphometric analysis of subchondral cortical and trabecular bone architecture was performed between and within the tibial condyles. Kruskal−Wallis and Wilcoxon signed-rank tests were used to examine the association between region, age, body mass, and each morphometric parameter. The findings indicate that age-related changes in mechanical loading have varied effects on subchondral bone morphology. With age, trabecular microstructure increased in bone volume fraction (p = 0.033) and degree of anisotropy (p = 0.012), and decreased in connectivity density (p = 0.001). In the subchondral cortical plate, there was an increase in thickness (p < 0.001). When comparing condylar regions, only degree of anisotropy differed (p = 0.004) between the medial and lateral condyles. Trabeculae in the medial condyle were more anisotropic than in the lateral region. This research represents an innovative approach to quantifying both cortical and trabecular subchondral bone microarchitecture in archaeological remains.

Properties of Cartilage-Subchondral Bone Junctions: A Narrative Review with Specific Focus on the Growth Plate

OBJECTIVE

The purpose of this narrative review is to summarize what is currently known about the structural, chemical, and mechanical properties of cartilage-bone interfaces, which provide tissue integrity across a bimaterial interface of 2 very different structural materials. Maintaining these mechanical interfaces is a key factor for normal bone growth and articular cartilage function and maintenance.

MATERIALS AND METHODS

A comprehensive search was conducted using Google Scholar and PubMed/Medline with a specific focus on the growth plate cartilage-subchondral bone interface. All original articles, reviews in journals, and book chapters were considered. Following a review of the overall structural and functional characteristics of the physis, the literature on histological studies of both articular and growth plate chondro-osseous junctions is briefly reviewed. Next the literature on biochemical properties of these interfaces is reviewed, specifically the literature on elemental analyses across the cartilage-subchondral bone junctions. The literature on biomechanical studies of these junctions at the articular and physeal interfaces is also reviewed and compared.

RESULTS

Unlike the interface between articular cartilage and bone, growth plate cartilage has 2 chondro-osseous junctions. The reserve zone of the mature growth plate is intimately connected to a plate of subchondral bone on the epiphyseal side. This interface resembles that between the subchondral bone and articular cartilage, although much less is known about its makeup and formation.

CONCLUSION

There is a notably paucity of information available on the structural and mechanical properties of reserve zone-subchondral epiphyseal bone interface. This review reveals that further studies are needed on the microstructural and mechanical properties of chondro-osseous junction with the reserve zone.

Biochemical and Morphological Abnormalities of Subchondral Bone and Their Association with Cartilage Degeneration in Spontaneous Osteoarthritis

This study aims to investigate how biochemical composition in subchondral bone (SB) relates to the sulfated glycosaminoglycan (sGAG) content of articular cartilage (AC) in the knee joint of guinea pigs from the early to moderate osteoarthritis (OA). Male Dunkin Hartley strain guinea pigs were grouped according to age (1, 3, 6, and 9 months, with 10 guinea pigs in each group). The biochemical properties of the AC and SB in the tibial plateau of the guinea pigs were determined through histology and Raman spectroscopy, respectively. Furthermore, the microstructures of the SB were investigated using micro-computed tomography (micro-CT) and histology. Increased thickness and bone mineral density (BMD) and decreased porosity were observed in the subchondral plate (SP) with the progression of spontaneous OA, accompanied by a decreasing trend in sGAG integrated optical density (IOD) of AC. Compared with the changes in the microstructure of subchondral bone, the content of sGAG was more correlated to the changes in the mineral/matrix ratio of subchondral bone. The mineralization of the matrix was significantly correlated to the content of sGAG compared with crystallinity/maturity and Type B carbonate substitution. PO₄^3- ν1/Amide III was more correlated to the content of sGAG than PO₄^3- ν1/Amide I, PO₄^3- ν1/CH₂ wag during the progression of spontaneous osteoarthritis. This study demonstrated that the mineralization of subchondral bone plays a crucial role in the pathogenesis of OA. Future studies may access to the mineralization of subchondral bone in addition to its microstructure in the study for pathogenesis and early diagnosis of osteoarthritis.

Development and validation of a novel high performance liquid chromatography-coupled with Corona charged aerosol detector method for quantification of glucosamine in dietary supplements

Introduction

Glucosamine dietary supplements are commonly used for the management of osteoarthritis (OA). However, clinical trials have reported varying outcomes with regard to joint function and disease progression. One of the possible reasons for variability in observed effects of glucosamine could be that, unlike prescription drugs, the quality of manufactured dietary supplements is not closely monitored in many countries. Therefore, there is the possibility that the actual amount of glucosamine present in a dietary supplement is different from that claimed on the label. The quality control of glucosamine supplements is further complicated by the unavailability of a simple and effective analytical method for the analysis of glucosamine. Therefore, the aim of this study was to develop a simple analytical method that could be easily adapted by the pharmaceutical industry for routine analysis of glucosamine.

Aims

To develop a novel high-performance liquid chromatography (HPLC) method for the quantification of glucosamine, and determine the amount of glucosamine present in a sample of dietary supplements commercially available in Australia and India.

Methods

Chromatographic separation of glucosamine was achieved using a zwitter-ionic hydrophilic interaction liquid chromatography column with a mobile phase consisting of 60% acetonitrile and 40% of 85 mM ammonium acetate, at a flow rate of 0.3 mL/min and column temperature 40°C. The developed method was validated for intra- and inter-day linearity, accuracy, precision, and reproducibility. The newly-developed method was subsequently used to analyse 12 glucosamine supplements.

Results

The developed method was selective for glucosamine, which had a retention time of 5.9 min. The standard curve was linear with a correlation coefficient (r²) exceeding 0.99, over the range of 10–200 μg/mL for glucosamine. The relative standard deviations for intra- and inter-day accuracy, precision and reproducibility were all less than 4%. The amount of glucosamine determined in six Australian and six Indian glucosamine supplements ranged between 98.7–101.7% and 85.9–101.8% of the labelled values, respectively.

Discussion

Unlike previous HPLC methods, this newly-developed HPLC technique does not require pre-derivatisation and can separate glucosamine from both hydrochloride and sulphate salts, and from other amino sugars, such as chondroitin sulphate present in dietary supplements. This simple and effective technique can be employed by analytical laboratories for the quality control of glucosamine dietary supplements.

Conclusion

The current study has developed a new analytical technique using HPLC-Corona CAD, which can analyse underivatised glucosamine hydrochloride and sulphate within 6 minutes. Using the novel assay, we confirmed that unlike the tested Australian dietary supplements, only half of the tested Indian products had a glucosamine content within ±10% of what was claimed on the label.

Morphological, biochemical and mechanical properties of articular cartilage and subchondral bone in rat tibial plateau are age related

The purpose of this study was to investigate age-related changes in the morphological, biochemical and mechanical properties of articular cartilage (AC) and subchondral bone in the rat tibial plateau. Female Wistar rats were grouped according to age (1, 3, 5, 7, 9, 11, 13, 15, 16 and 17 months, with 10 rats in each group). The ultrastructures, surface topographies, and biochemical and mechanical properties of the AC and subchondral bone in the knee joints of the rats were determined through X-ray micro-tomography, histology, immunohistochemistry, scanning electron microscopy (SEM), atomic force microscopy and nanoindentation. We found that cartilage thickness decreased with age. This decrease was accompanied by functional condensation of the underlying subchondral bone. Increased thickness and bone mineral density and decreased porosity were observed in the subchondral plate (SP). Growth decreased collagen II expression in the tibial cartilage. The arrangement of trabeculae in the subchondral trabecular bone became disordered. The thickness and strength of the fibers decreased with age, as detected by SEM. The SP and trabeculae in the tibial plateau increased in roughness in the first phase (1-9 months of age), and then were constant in the second phase (11-17 months of age). Meanwhile, the roughness of the AC changed significantly in the first phase (1-9 months of age), but the changes were independent of age thereafter. This study gives a comprehensive insight into the growth-related structural, biochemical and mechanical changes in the AC and subchondral bone. The results presented herein may contribute to a new understanding of the pathogenesis of age-related bone diseases.

THE MARKERS OF BONE METABOLISM AND SYSTEM INFLAMMATION IN PATIENTS WITH OSTEOARTHRITIS DEPENDING ON BODY MASS, THE INFLUENCE OF SYMPTOMATIC SLOW ACTING DRUGS

Aim. To assess the levels of markers of the bone synthesis and system inflammation in patients with osteoarthritis (OA) in combination with obesity and their dynamic under the influence of basic treatment. Materials and methods. The research included 40 women with OA, 46–78 years old (mean age – 59,8±1,5 years). Duration of the disease varied from 3 to 36 years (mean duration – 10,0±1,1 years). Mean body mass index (BMI) among patients was 30,6±0,7 [22,3; 39,5]kg/m2, according to which patients were divided in 3 groups: patients with OA without obesity (n=17), patients with OA with 1 degree of obesity (n=14), patients with OA with 2 degree of obesity (n=9). The level of osteochondral metabolism was assessed using quantitative measuring of the levels of procollagen IC-terminal propeptide (РІСР), (Cloud-CloneCorp. “procollagen IC-Terminal Propeptide”, USA) and osteocalcin (Roche Diagnostics «N-MID Osteocalcin», Switzerland) on analyzer «ELECSYS 2010» by the method of immune-enzyme analysis; the level of the system inflammation was assessed by the level of C-reactive protein (CRP) by the method of immunoturbidimetry. The clinical efficacy was assessed by the dynamics of intensity levels of pain syndromes at physical load and at rest by the visual-analogue scale (VAS). The measuring of РІСР, osteocalcin and CRP levels and also the assessment of clinical efficacy as to the decrease of pain syndrome were carried out twice – at the beginning and at the end of observation. The period of observation is 2 months. Results. The presence of direct correlation between РІСР and BMI (r=0,62; р=0,008) among patients with OA in combination with the normal body weight was established at the research, whereas among patients with OA in combination with obesity the analogous correlation was demonstrated between SRP and BMI (r=0,43; р=0,04) on the background of correlation of PICP and OC levels (r=0,46; р=0,03). Obesity in patients with OA was associated with the reliably higher levels of pain at both rest and physical load from the side of knee joints, with maximal intensity of the pain syndrome among patients with OA and 1 degree of obesity. Statistical analysis did not reveal the reliable dependence of РІСР and OC in patients with OA from the initial CRP level on the background of tendency to the higher РІСР level and lower OC level among patients with initially increased CRP level comparing with ones with normal CRP level. The therapy with basic preparations at OA during 2 months among patients with OA with increased CRP level led to the reliable decrease of РІСР level (р=0,0076) and the tendency to increase of OC level (р˃0,05), without the reliably significant difference between the initial and final РІСР and OC levels among patients with OA and normal CRP level. At the end of observation period the maximal analgesic effect was demonstrated as to the articulate pain at rest from the side of knee joints (р˂0,001) among patients with OA, who received diacerein, with clinically comparable effect from the side of other aticulate zones (р˂0,05), that was associated with reliable decrease of CRP level (р=0,013). Discussion. The received results testify that the control of the system inflammation level at OA is a target not only relative to the decrease of pain syndrome but also conditions the stable state of subchondral bone (SCB), providing the compensation of processes of destruction and synthesis in bone tissue. The significance of procollagen IC-terminal propeptide (РІСР) and osteocalcin (OC) as the markers of bone synthesis that are able to reflect metabolic processes in SCB at OA, and also the discordant influence of CRP level on PICP level at the relative stability of OC level were demonstrated at the research. The received results allow consider the inflammatory process at OA as a target for preservance of the bone tissue, conditioning the expedience of taking into account the ability of OA basic preparations to realize the control influence on the level of system inflammation. Diacerein that in ESCEO recommendations (2014) is related to the preparations of the 1 step of treatment of patients with OA provides the control on inflammation and stability of osteocalcin level that testifies to the balance of catabolic processes in SCB. Conclusions. At OA the levels of procollagen IC-terminal propeptide (РІСР) and osteocalcin (OC) were not associated with obesity and did not depend on the initial CRP level at the presence of correlation between РІСР level and BMI among patients with OA with the normal body weight and BMI and CRP level among patients with OA in combination with obesity. The absence of reliable dynamics from РІСР side and maintenance of the stable OC level on the background of the reliable anti-inflammatory effect at using diacerein in patients with OA can testify to the compensatory adequacy of reparation processes in SCB.

Acute exercise modifies titin phosphorylation and increases cardiac myofilament stiffness

Titin-based myofilament stiffness is largely modulated by phosphorylation of its elastic I-band regions N2-Bus (decreases passive stiffness, PT) and PEVK (increases PT). Here, we tested the hypothesis that acute exercise changes titin phosphorylation and modifies myofilament stiffness. Adult rats were exercised on a treadmill for 15 min, untrained animals served as controls. Titin phosphorylation was determined by Western blot analysis using phosphospecific antibodies to Ser4099 and Ser4010 in the N2-Bus region (PKG and PKA-dependent. respectively), and to Ser11878 and Ser 12022 in the PEVK region (PKCα and CaMKIIδ-dependent, respectively). Passive tension was determined by step-wise stretching of isolated skinned cardiomyocytes to sarcomere length (SL) ranging from 1.9 to 2.4 μm and showed a significantly increased PT from exercised samples, compared to controls. In cardiac samples titin N2-Bus phosphorylation was significantly decreased by 40% at Ser4099, however, no significant changes were observed at Ser4010. PEVK phosphorylation at Ser11878 was significantly increased, which is probably mediated by the observed exercise-induced increase in PKCα activity. Interestingly, relative phosphorylation of Ser12022 was substantially decreased in the exercised samples. Surprisingly, in skeletal samples from acutely exercised animals we detected a significant decrease in PEVK phosphorylation at Ser11878 and an increase in Ser12022 phosphorylation; however, PKCα activity remained unchanged. In summary, our data show that a single exercise bout of 15 min affects titin domain phosphorylation and titin-based myocyte stiffness with obviously divergent effects in cardiac and skeletal muscle tissues. The observed changes in titin stiffness could play an important role in adapting the passive and active properties of the myocardium and the skeletal muscle to increased physical activity.