Custom-Made Articulating Spacer (CUMARS): The Resolution of Periosteal Reaction and Femur Remodelling in Periprosthetic Hip Infection.

Periprosthetic joint infection (PJI) is one of the most common complications after total hip arthroplasty (THA). Two-stage revision surgery is one of the treatment options for PJI, however, it has been associated with poor patient tolerance, reduced patient mobility, and periarticular tissue contracture leading to difficulty during second-stage reconstruction. The custom-made articulating spacer (CUMARS) was developed to provide an alternative that is better tolerated and to reduce the complexity of second-stage reconstruction. This study details the treatment of a patient with PJI post-THA with significant periosteal reaction using a CUMARS construct, which enabled immediate post-operative weight bearing, eventual eradication of infection, restoration of femoral bone stock, and avoidance of second-stage reconstruction.

Topical nonsteroidal anti-inflammatory drugs for management of osteoarthritis pain: A consensus recommendation.

Osteoarthritis (OA) contributes to significant medical and socioeconomic burden in many populations. Its prevalence is expected to rise continuously owing to the combined effects of aging and increase in risk factors, including obesity, physical inactivity, and joint injuries. Pain is a hallmark presentation of OA. Topical nonsteroidal anti-inflammatory drugs (NSAIDs) are recommended by many international guidelines as an early treatment option of the management of osteoarthritic pain. However, the use of topical NSAIDs remains low in Malaysia and appears not to be a preferred agent in managing OA pain by prescribers. There is also limited guidance from local medical bodies on the use of topical NSAIDs to manage OA pain. This consensus recommendation is intended to serve as a practical guide for healthcare practitioners on the use of topical NSAIDs in the management of OA pain. Eight statements and recommendations were finalized covering the areas of OA burden, topical NSAIDs formulations, safety and efficacy of topical NSAIDs, and patient education. Robust evidence is available to support the efficacy and safety of topical NSAIDs, with its benefits further strengthened by ease of use and access. Taking these into consideration, we recommend that healthcare practitioners advocate for the early use of topical NSAIDs over oral NSAIDs for mild-to-moderate OA pain, while engaging in a shared decision-making process with patients for optimal clinical outcomes.

Gender differences in the associations between knee pain and urinary incontinence in older adults: Cross-sectional analysis from the Malaysian Elders Longitudinal Research Study (MELoR).

INTRODUCTION: The common assumption that urinary incontinence occurs in osteoarthritis (OA) due to poor mobility is supported by limited evidence. The influence of gender in such associations is also yet to be elucidated. OBJECTIVE: This study, therefore, identified any potential associations between knee OA symptoms and urinary incontinence and further explore sex differences in the associations. DESIGN: Cross-sectional study. SETTING: University Hospital. PARTICIPANTS: This was a cross-sectional study from a longitudinal research study comprising 1221 community-dwelling older persons (57% women), mean age (SD) 68.95 (7.49) years. MAIN OUTCOME MEASURE(S): Presence of urinary incontinence: mixed, stress and urge symptoms. Physical performance and C-reactive protein levels were also assessed. RESULTS: Two hundred and seventy-seven (22.83%) individuals reported the presence of urinary incontinence: mixed (41.5%), stress (30%), and urge (28.5%) symptoms. In an unadjusted analysis, stratified by gender, the association between knee pain and urinary incontinence was only present in women with mixed symptoms. After further adjustment of demographics differences and body mass index, the association between knee pain with any urinary incontinence and mixed symptoms remained significant with the odds ratios (95% confidence interval): 1.48 (1.02-2.15) and 1.73 (1.06-2.83), respectively. This relationship was attenuated after further adjustment for waist circumference and impaired lower limb mobility. CONCLUSION: Our study refutes previous assumptions that urinary incontinence in individuals with OA is attributed to impaired mobility alone, but introduces the role of abdominal obesity in this relationship, particularly in women. Future studies should assess the temporal relationship between body fat distribution and OA with urinary incontinence.

Mechanical compression controls the biosynthesis of human osteoarthritic chondrocytes in vitro.

BACKGROUND: Cartilage damage, which can potentially lead to osteoarthritis, is a leading cause of morbidity in the elderly population. Chondrocytes are sensitive to mechanical stimuli and their matrix-protein synthesis may be altered when chondrocytes experience a variety of in vivo loadings. Therefore, a study was conducted to evaluate the biosynthesis of isolated osteoarthritic chondrocytes which subjected to compression with varying dynamic compressive strains and loading durations. METHODS: The proximal tibia was resected as a single osteochondral unit during total knee replacement from patients (N = 10). The osteoarthritic chondrocytes were isolated from the osteochondral units, and characterized using reverse transcriptase-polymerase chain reaction. The isolated osteoarthritic chondrocytes were cultured and embedded in agarose, and then subjected to 10% and 20% uniaxial dynamic compression up to 8-days using a bioreactor. The morphological features and changes in the osteoarthritic chondrocytes upon compression were evaluated using scanning electron microscopy. Safranin O was used to detect the presence of cartilage matrix proteoglycan expression while quantitative analysis was conducted by measuring type VI collagen using an immunohistochemistry and fluorescence intensity assay. FINDINGS: Gene expression analysis indicated that the isolated osteoarthritic chondrocytes expressed chondrocyte-specific markers, including BGN, CD90 and HSPG-2. Moreover, the compressed osteoarthritic chondrocytes showed a more intense and broader deposition of proteoglycan and type VI collagen than control. The expression of type VI collagen was directly proportional to the duration of compression in which 8-days compression was significantly higher than 4-days compression. The 20% compression showed significantly higher intensity compared to 10% compression in 4- and 8-days. INTERPRETATION: The biosynthetic activity of human chondrocytes from osteoarthritic joints can be enhanced using selected compression regimes.

Modulation of the mechanical responses of synovial fibroblasts by osteoarthritis-associated inflammatory stressors.

OBJECTIVES: To compare mechanobiological response of synovial fibroblasts (SFb) from OA patient cohorts under mechanical load and inflammatory stressors for better understanding of SFb homeostatic functions. METHODS: Primary SFb isolated from knee synovium of OA obese (OA-ob:SFb), OA-pre-obese (OA-Pob:SFb), non-OA arthroscopic (scope:SFb), and non-OA arthroscopic with cartilage damage (scope-CD:SFb) were exposed to OA-conditioned media (OACM), derived from OA obese (OA-ob:CM), OA-pre-obese (OA-Pob:CM), and mechanical stretch at either 0 %, 6 % or 10 % for 24 h. Differences in the mRNA levels of genes involved in extracellular matrix production, inflammation and secretory activity were measured. RESULTS: Despite the significant BMI differences between the OA-ob and OA-Pob groups, OA-Pob has more patients with underlying dyslipidaemia, and low-grade synovitis with higher levels of secreted proteins, CXCL8, COL4A1, CCL4, SPARC and FGF2 in OA-Pob:CM. All primary SFb exhibited anti-proliferative activity with both OA-CM. Mechanical stretch stimulated lubricin production in scope:SFb, higher TGFß1 and COL1A1 expressions in scope-CD:SFb. OA-Pob:CM stimulated greater detrimental effects than the OA-ob:CM, with higher pro-inflammatory cytokines, IL1ß, IL6, COX2 and proteases such as aggrecanases, ADAMTS4 and ADAMTS5, and lower ECM matrix, COL1A1 expressions in all SFb. OA-ob:SFb were unresponsive but expressed higher pro-inflammatory cytokines under OA-Pob:CM treatment. CONCLUSION: Both mechanical and inflammatory stressors regulate SFb molecular functions with heterogeneity in responses that are dependent on their pathological tissue of origins. While mechanical stretch promotes a favorable effect with enhanced lubricin production in scope:SFb and TGFß1 and COL1A1 in scope-CD:SFb, the presence of excessively high OA-associated inflammatory mediators in OA-Pob:CM, predominantly SPARC, CXCL8 and FGF2 drive all SFb regardless of pathology, towards greater pro-inflammatory activities.

Factors Determining the Increased Risk of Falls in Individuals With Knee Pain in the Malaysian Elders Longitudinal Research (MELoR) Study.

Objectives: While the negative impact of falls in older persons has been recognized, the association between knee pains and falls remains inconclusive due to underreporting and undertreatment of knee pain. This study was conducted to evaluate the relationship between knee pain and knee pain severity with falls risk and to further determine factors which influence this potential relationship. Design: This was cross-sectional study from the Malaysian Elders Longitudinal Research (MELoR) study. Setting: Urban community dwellers in a middle-income South East Asian country. Participants: One thousand two hundred twelve of a representative sample of community dwelling older persons aged 55 years and older. Outcome measures: Falls in the preceding 12 months and knee pain were collected during a home-based computer-assisted interview. Physical and functional performance were measured using the Timed Up and Go test and the Katz and Lawton scales, respectively. Psychological status was determined using the Depression Anxiety and Stress Scale (DASS-21). Results: Of the 1,212 participants included in this analysis, knee pain was present in 402 (33.17%) individuals (124 (30.85%) mild, 210 (52.24%) moderate, 68 (16.92%) severe). The presence of knee pain was associated with increased risk of falls [odds Ratio, OR(95% confidence interval, CI): 1.81 (1.37-2.38)]. Severe knee pain was an independent predictor for falls after adjustment for functional impairment and psychological status. Mild, moderate, and severe knee pain had a specific indirect effect on falls through reducing functional impairment, which in turn increases their psychological concern. Conclusion: Future studies should explore this relationship prospectively and evaluate whether interventions which alleviate psychological concerns and improve function will reduce falls risk in those with mild to moderate knee pain.

Ethnic differences in the prevalence, socioeconomic and health related risk factors of knee pain and osteoarthritis symptoms in older Malaysians.

Knee pain is often underreported, underestimated and undertreated. This study was conducted to estimate the prevalence, burden and further identify socioeconomic factors influencing ethnic differences in knee pain and symptoms of OA among older adults aged 55 years and over in Greater Kuala Lumpur (the capital city of Malaysia). The sample for the Malaysian Elders Longitudinal Research (MELoR) was selected using stratified random sampling, by age and ethnicity from the electoral rolls of three parliamentary constituencies. Information on knee pain was available in 1226 participants, mean age (SD) 68.96 (1.57) years (409 Malay, 416 Chinese, 401 Indian). The crude and weighted prevalence of knee pain and self-reported knee OA symptoms were 33.3% and 30.8% respectively. There were significant ethnic differences in knee pain (crude prevalence: Malays 44.6%, Chinese 23.5% and Indians 31.9%, p<0.001). The presence of two or more non-communicable diseases (NCD) attenuated the increased risk of knee pain among the ethnic Indians compared to the ethnic Chinese. The prevalence of knee pain remained significantly higher among the ethnic Malays after adjustment for confounders. While the prevalence of knee pain in our older population appears similar to that reported in other published studies in Asia, the higher prevalence among the ethnic Malays has not previously been reported. Further research to determine potential genetic susceptibility to knee pain among the ethnic Malays is recommended.

APSIC guidelines for the prevention of surgical site infections.

Background: The Asia Pacific Society of Infection Control (APSIC) launched the APSIC Guidelines for the Prevention of Surgical Site Infections in 2018. This document describes the guidelines and recommendations for the setting prevention of surgical site infections (SSIs). It aims to highlight practical recommendations in a concise format designed to assist healthcare facilities at Asia Pacific region in achieving high standards in preoperative, perioperative and postoperative practices. Method: The guidelines were developed by an appointed workgroup comprising experts in the Asia Pacific region, following reviews of previously published guidelines and recommendations relevant to each section. Results: It recommends that healthcare facilities review specific risk factors and develop effective prevention strategies, which would be cost effective at local levels. Gaps identified are best closed using a quality improvement process. Surveillance of SSIs is recommended using accepted international methodology. The timely feedback of the data analysed would help in the monitoring of effective implementation of interventions. Conclusions: Healthcare facilities should aim for excellence in safe surgery practices. The implementation of evidence-based practices using a quality improvement process helps towards achieving effective and sustainable results.

Uniaxial Cyclic Tensile Stretching at 8% Strain Exclusively Promotes Tenogenic Differentiation of Human Bone Marrow-Derived Mesenchymal Stromal Cells.

The present study was conducted to establish the amount of mechanical strain (uniaxial cyclic stretching) required to provide optimal tenogenic differentiation expression in human mesenchymal stromal cells (hMSCs) in vitro, in view of its potential application for tendon maintenance and regeneration. Methods. In the present study, hMSCs were subjected to 1 Hz uniaxial cyclic stretching for 6, 24, 48, and 72 hours; and were compared to unstretched cells. Changes in cell morphology were observed under light and atomic force microscopy. The tenogenic, osteogenic, adipogenic, and chondrogenic differentiation potential of hMSCs were evaluated using biochemical assays, extracellular matrix expressions, and selected mesenchyme gene expression markers; and were compared to primary tenocytes. Results. Cells subjected to loading displayed cytoskeletal coarsening, longer actin stress fiber, and higher cell stiffness as early as 6 hours. At 8% and 12% strains, an increase in collagen I, collagen III, fibronectin, and N-cadherin production was observed. Tenogenic gene expressions were highly expressed (p < 0.05) at 8% (highest) and 12%, both comparable to tenocytes. In contrast, the osteoblastic, chondrogenic, and adipogenic marker genes appeared to be downregulated. Conclusion. Our study suggests that mechanical loading at 8% strain and 1 Hz provides exclusive tenogenic differentiation; and produced comparable protein and gene expression to primary tenocytes.

Vitamin D deficiency is associated with ethnicity and knee pain in a multi-ethnic South-East Asian nation: Results from Malaysian Elders Longitudinal Research (MELoR).

AIM: To determine the association between vitamin D and knee pain among participants of the Malaysian Elders Longitudinal Research (MELoR) study. METHOD: This was a cross-sectional study from the MELoR study consisting of a representative group of 1011 community-dwelling older persons (57% female), mean age 86.5 (54-94) years; 313 were Malays, 367 Chinese and 330 Indians. Participants were asked if they had knee pain. Levels of serum 25-hydroxy cholecalciferol (25-[OH]D), an indicator of vitamin D status, were measured using routine laboratory techniques. RESULTS: In unadjusted analysis, presence of knee pain was significantly associated with vitamin D deficiency (odds ratio [OR] 1.42; 95% confidence interval (CI) 1.08-1.85, P 0.011). Vitamin D levels were significantly associated with ethnicity differences where Malays (OR 7.08; 95% CI 4.94-10.15) and Indians (OR 6.10; 95% CI 4.28-9.71) have lower levels of vitamin D compared to Chinese. Subsequent multivariate analysis revealed that the association between vitamin D deficiency and knee pain was confounded by ethnic differences. CONCLUSION: A previous study suggested that vitamin D deficiency was associated with knee pain. This relationship was reproduced in our study, but we further established that the association was explained by ethnic variations. As vitamin D status is dependent on skin tone, diet and sunlight exposure, which are all effected by ethnicity, future studies are now required to determine whether a true relationship exists between vitamin D and knee pain.

Factors Influencing the Successful Isolation and Expansion of Aging Human Mesenchymal Stem Cells.

Most studies highlight mesenchymal stem cells (MSCs) extracted primarily from bone marrow (BM), very few report the use of peripheral blood (PB), often due to the associated low seeding density and difficulties with extraction techniques. As ageing populations are becoming more predominant globally, together with escalating demands for MSC transplantation and tissue regeneration, obtaining quality MSCs suitable for induced differentiation and biological therapies becomes increasingly important. In this study, BM and PB were obtained from elderly patients and extracted MSCs grown in vitro to determine their successful isolation and expansion. Patients' socio-demographic background and other medical information were obtained from medical records. Successful and failed cultures were correlated with key demographic and medical parameters. A total of 112 samples (BM or PB) were used for this study. Of these, 50 samples (44.6%) were successfully cultured according to standardised criteria with no signs of contamination. Our comparative analyses demonstrated no statistical correlation between successful MSC cultures and any of the six demographic or medical parameters examined, including sample quantity, age, sex, race, habits and underlying comorbidities of sample donors. In conclusion, the present study demonstrates that typical demographics and comorbidities do not influence successful MSC isolation and expansion in culture.

Enhancement of mesenchymal stem cell chondrogenesis with short-term low intensity pulsed electromagnetic fields.

Pulse electromagnetic fields (PEMFs) have been shown to recruit calcium-signaling cascades common to chondrogenesis. Here we document the effects of specified PEMF parameters over mesenchymal stem cells (MSC) chondrogenic differentiation. MSCs undergoing chondrogenesis are preferentially responsive to an electromagnetic efficacy window defined by field amplitude, duration and frequency of exposure. Contrary to conventional practice of administering prolonged and repetitive exposures to PEMFs, optimal chondrogenic outcome is achieved in response to brief (10 minutes), low intensity (2 mT) exposure to 6 ms bursts of magnetic pulses, at 15 Hz, administered only once at the onset of chondrogenic induction. By contrast, repeated exposures diminished chondrogenic outcome and could be attributed to calcium entry after the initial induction. Transient receptor potential (TRP) channels appear to mediate these aspects of PEMF stimulation, serving as a conduit for extracellular calcium. Preventing calcium entry during the repeated PEMF exposure with the co-administration of EGTA or TRP channel antagonists precluded the inhibition of differentiation. This study highlights the intricacies of calcium homeostasis during early chondrogenesis and the constraints that are placed on PEMF-based therapeutic strategies aimed at promoting MSC chondrogenesis. The demonstrated efficacy of our optimized PEMF regimens has clear clinical implications for future regenerative strategies for cartilage.

Three-Dimensional Computed Tomography Analysis of the Posterior Tibial Slope in 100 Knees.

BACKGROUND: The posterior tibial slope (PTS) is an important consideration in knee arthroplasty. However, there is still no consensus for the optimal slope. The objectives of this study were (1) to reliably determine the native PTS in this population using 3-dimensional computed tomography scans and (2) to determine the normal reference range for PTS in this population. METHODS: One hundred computed tomography scans of disease-free knees were analyzed. A 3-dimensional reconstructed image of the tibia was generated and aligned to its anatomic axis in the coronal and sagittal planes. The tibia was then rotationally aligned to the tibial plateau (tibial centroid axis) and PTS was measured from best-fit planes on the surface of the proximal tibia and individually for the medial and lateral plateaus. This was then repeated with the tibia rotationally aligned to the ankle (transmalleolar axis). RESULTS: When rotationally aligned to the tibial plateau, the mean PTS, medial PTS, and lateral PTS were 11.2° ± 3.0 (range, 4.7°-17.7°), 11.3° ± 3.2 (range, 2.7°-19.7°), and 10.9° ± 3.7 (range, 3.5°-19.4°), respectively. When rotationally aligned to the ankle, the mean PTS, medial PTS, and lateral PTS were 11.4° ± 3.0 (range, 5.3°-19.3°), 13.9° ± 3.7 (range, 3.1°-24.4°), and 9.7° ± 3.6 (range, 0.8°-17.7°), respectively. CONCLUSION: The PTS in the normal Asian knee is on average 11° (mean) with a reference range of 5°-17° (mean ± 2 standard deviation). This has implications to surgery and implant design.

Fate of tenogenic differentiation potential of human bone marrow stromal cells by uniaxial stretching affected by stretch-activated calcium channel agonist gadolinium.

The role for mechanical stimulation in the control of cell fate has been previously proposed, suggesting that there may be a role of mechanical conditioning in directing mesenchymal stromal cells (MSCs) towards specific lineage for tissue engineering applications. Although previous studies have reported that calcium signalling is involved in regulating many cellular processes in many cell types, its role in managing cellular responses to tensile loading (mechanotransduction) of MSCs has not been fully elucidated. In order to establish this, we disrupted calcium signalling by blocking stretch-activated calcium channel (SACC) in human MSCs (hMSCs) in vitro. Passaged-2 hMSCs were exposed to cyclic tensile loading (1 Hz + 8% for 6, 24, 48, and 72 hours) in the presence of the SACC blocker, gadolinium. Analyses include image observations of immunochemistry and immunofluorescence staining from extracellular matrix (ECM) production, and measuring related tenogenic and apoptosis gene marker expression. Uniaxial tensile loading increased the expression of tenogenic markers and ECM production. However, exposure to strain in the presence of 20 µM gadolinium reduced the induction of almost all tenogenic markers and ECM staining, suggesting that SACC acts as a mechanosensor in strain-induced hMSC tenogenic differentiation process. Although cell death was observed in prolonged stretching, it did not appear to be apoptosis mediated. In conclusion, the knowledge gained in this study by elucidating the role of calcium in MSC mechanotransduction processes, and that in prolonged stretching results in non-apoptosis mediated cell death may be potential useful for regenerative medicine applications.

The Combined Effect of Substrate Stiffness and Surface Topography on Chondrogenic Differentiation of Mesenchymal Stem Cells.

Stem cell differentiation is guided by contact with the physical microenvironment, influence by both topography and mechanical properties of the matrix. In this study, the combined effect of substratum nano-topography and mechanical stiffness in directing mesenchymal stem cell (MSC) chondrogenesis was investigated. Three polyesters of varying stiffness were thermally imprinted to create nano-grating or pillar patterns of the same dimension. The surface of the nano-patterned substrate was coated with chondroitin sulfate (CS) to provide an even surface chemistry, with cell-adhesive and chondro-inductive properties, across all polymeric substrates. The surface characteristic, mechanical modulus, and degradation of the CS-coated patterned polymeric substrates were analyzed. The cell morphology adopted on the nano-topographic surfaces were accounted by F-actin distribution, and correlated to the cell proliferation and chondrogenic differentiation outcomes. Results show that substratum stiffness and topographical cues affected MSC morphology and aggregation, and influenced the phenotypic development at the earlier stage of chondrogenic differentiation. Hyaline-like cartilage with middle/deep zone cartilage characteristics was generated on softer pillar surface, while on stiffer nano-pillar material MSCs showed potential to generate constituents of hyaline/fibro/hypertrophic cartilage. Fibro/superficial zone-like cartilage could be derived from nano-grating of softer stiffness, while stiffer nano-grating resulted in insignificant chondrogenesis. This study demonstrates the possibility of refining the phenotype of cartilage generated from MSCs by manipulating surface topography and material stiffness.

Platelet-rich concentrate in serum free medium enhances osteogenic differentiation of bone marrow-derived human mesenchymal stromal cells.

Previous studies have shown that platelet concentrates used in conjunction with appropriate growth media enhance osteogenic differentiation of human mesenchymal stromal cells (hMSCs). However, their potential in inducing osteogenesis of hMSCs when cultured in serum free medium has not been explored. Furthermore, the resulting osteogenic molecular signatures of the hMSCs have not been compared to standard osteogenic medium. We studied the effect of infrequent supplementation (8-day interval) of 15% non-activated platelet-rich concentrate (PRC) in serum free medium on hMSCs proliferation and differentiation throughout a course of 24 days, and compared the effect with those cultured in a standard osteogenic medium (OM). Cell proliferation was analyzed by alamar blue assay. Gene expression of osteogenic markers (Runx2, Collagen1, Alkaline Phosphatase, Bone morphogenetic protein 2, Osteopontin, Osteocalcin, Osteonectin) were analyzed using Q-PCR. Immunocytochemical staining for osteocalcin, osteopontin and transcription factor Runx2 were done at 8, 16 and 24 days. Biochemical assays for the expression of ALP and osteocalcin were also performed at these time-points. Osteogenic differentiation was further confirmed qualitatively by Alizarin Red S staining that was quantified using cetylpyridinium chloride. Results showed that PRC supplemented in serum free medium enhanced hMSC proliferation, which peaked at day 16. The temporal pattern of gene expression of hMSCs under the influence of PRC was comparable to that of the osteogenic media, but at a greater extent at specific time points. Immunocytochemical staining revealed stronger staining for Runx2 in the PRC-treated group compared to OM, while the staining for Osteocalcin and Osteopontin were comparable in both groups. ALP activity and Osteocalcin/DNA level were higher in the PRC group. Cells in the PRC group had similar level of bone mineralization as those cultured in OM, as reflected by the intensity of Alizarin red stain. Collectively, these results demonstrate a great potential of PRC alone in inducing proliferation of hMSCs without any influence from other lineage-specific growth media. PRC alone has similar capacity to enhance hMSC osteogenic differentiation as a standard OM, without changing the temporal profile of the differentiation process. Thus, PRC could be used as a substitute medium to provide sufficient pool of pre-differentiated hMSCs for potential clinical application in bone regeneration.

Three dimensional alginate-fucoidan composite hydrogel augments the chondrogenic differentiation of mesenchymal stromal cells.

Presence of sulfated polysaccharides like heparan sulphate has often been implicated in the regulation of chondrogenesis. However, recently there has been a plethora of interest in the use of non-animal extracted analogs of heparan sulphate. Here we remodeled alginate (1.5%) by incorporating fucoidan (0.5%), a natural sulphated polysaccharide extracted from seaweeds to form a composite hydrogel (Al-Fu), capable of enhancing chondrogenesis of human mesenchymal stromal cells (hMSCs). We confirmed the efficiency of fucoidan incorporation by FTIR and EDX analysis. Further, its ability to support hMSC attachment and chondrogenic differentiation was confirmed by SEM, biochemical glycosaminoglycan quantification, real-time quantitative PCR and immunocytochemical analyses of chondrogenic markers Sox-9, Collagen II, Aggrecan and COMP. Effect of Al-Fu hydrogel on hMSC hypertrophy was also confirmed by the downregulation of hypertrophic genes Collagen X and Runx2. This composite scaffold can hence be used as a cartilage biomimetic biomaterial to drive hMSC chondrogenesis and for other cartilage repair based therapies.

Proliferation and osteogenic differentiation of mesenchymal stromal cells in a novel porous hydroxyapatite scaffold.

AIM: To compare the effect of bovine bone derived porous hydroxyapatite (BDHA) scaffold on proliferation and osteogenic differentiation of human bone marrow-derived mesenchymal stromal cells (hMSCs) compared with commercial hydroxyapatite (CHA) scaffold. MATERIALS AND METHODS: The porosity and pore size were analyzed using micro-CT. The biocompatibility was demonstrated by alamar blue assay, and cell attachment through SEM and Hoechst staining. The osteogenic differentiation was demonstrated using biochemical assay and osteogenic gene expression. RESULTS: BDHA and CHA scaffolds showed porosity of 76.6 ± 0.6 and 64.3 ± 0.3% and pore size diameter of 0.04-0.25 and 0.1-2.6 mm, respectively. hMSCs proliferation, ALP activity, osteocalcin secretion and osteogenic gene expression are comparable in both the scaffolds. CONCLUSION: These results demonstrated that BDHA is biocompatible, supports cell adhesion and promotes proliferation and osteogenic differentiation.

The proliferation and tenogenic differentiation potential of bone marrow-derived mesenchymal stromal cell are influenced by specific uniaxial cyclic tensile loading conditions.

It has been previously demonstrated that mechanical stimuli are important for multipotent human bone marrow-derived mesenchymal stromal cells (hMSCs) to maintain good tissue homeostasis and even to enhance tissue repair processes. In tendons, this is achieved by promoting the cellular proliferation and tenogenic expression/differentiation. The present study was conducted to determine the optimal loading conditions needed to achieve the best proliferation rates and tenogenic differentiation potential. The effects of mechanical uniaxial stretching using different rates and strains were performed on hMSCs cultured in vitro. hMSCs were subjected to cyclical uniaxial stretching of 4, 8 or 12 % strain at 0.5 or 1 Hz for 6, 24, 48 or 72 h. Cell proliferation was analyzed using alamarBlue[Formula: see text] assay, while hMSCs differentiation was analyzed using total collagen assay and specific tenogenic gene expression markers (type I collagen, type III collagen, decorin, tenascin-C, scleraxis and tenomodulin). Our results demonstrate that the highest cell proliferation is observed when 4 % strain [Formula: see text] 1 Hz was applied. However, at 8 % strain [Formula: see text] 1 Hz loading, collagen production and the tenogenic gene expression were highest. Increasing strain or rates thereafter did not demonstrate any significant increase in both cell proliferation and tenogenic differentiation. In conclusion, our results suggest that 4 % [Formula: see text] 1 Hz cyclic uniaxial loading increases cell proliferation, but higher strains are required for superior tenogenic expressions. This study suggests that selected loading regimes will stimulate tenogenesis of hMSCs.

PVA-chitosan composite hydrogel versus alginate beads as a potential mesenchymal stem cell carrier for the treatment of focal cartilage defects.

PURPOSE: To investigate whether mesenchymal stem cells (MSCs) seeded in novel polyvinyl alcohol (PVA)-chitosan composite hydrogel can provide comparable or even further improve cartilage repair outcomes as compared to previously established alginate-transplanted models. METHODS: Medial femoral condyle defect was created in both knees of twenty-four mature New Zealand white rabbits, and the animals were divided into four groups containing six animals each. After 3 weeks, the right knees were transplanted with PVA-chitosan-MSC, PVA-chitosan scaffold alone, alginate-MSC construct or alginate alone. The left knee was kept as untreated control. Animals were killed at the end of 6 months after transplantation, and the cartilage repair was assessed through Brittberg morphological score, histological grading by O'Driscoll score and quantitative glycosaminoglycan analysis. RESULTS: Morphological and histological analyses showed significant (p < 0.05) tissue repair when treated with PVA-chitosan-MSC or alginate MSC as compared to the scaffold only and untreated control. In addition, safranin O staining and the glycosaminoglycan (GAG) content were significantly higher (p < 0.05) in MSC treatment groups than in scaffold-only or untreated control group. No significant difference was observed between the PVA-chitosan-MSC- and alginate-MSC-treated groups. CONCLUSION: PVA-chitosan hydrogel seeded with mesenchymal stem cells provides comparable treatment outcomes to that of previously established alginate-MSC construct implantation. This study supports the potential use of PVA-chitosan hydrogel seeded with MSCs for clinical use in cartilage repair such as traumatic injuries.