Higher ratios of chondrocyte to mesenchymal stem cells elevate the therapeutic effects of extracellular vesicles harvested from chondrocyte/mesenchymal stem cell co-culture on osteoarthritis in a rat model.

Extracellular vesicles (EVs) may have a key therapeutic role and offer an innovative treatment for osteoarthritis (OA). Studies have shown that ratio of MSC/chondrocyte could affect their therapeutic outcomes. Here, we investigate the chondrogenic potential and therapeutic effect of EVs derived from MSCs and chondrocytes in the naïve, chondrogenically primed, and co-culture states to treat OA. EVs are isolated from naïve MSCs (M-EV), chondrogenically primed MSCs (cpM-EV), chondrocytes (C-EV), and co-cultures of chondrocytes plus MSCs at ratios of 1:1 (C/M-EV), 2:1 (2C/M-EV), and 4:1 (4C/M-EV). We characterized the isolated EVs in terms of surface markers, morphology, size, and zeta potential, and evaluated their chondrogenic potential in vitro by qRT-PCR and histological analyses. Next, these EVs were intra-articularly injected into osteoarthritic cartilage of a rat model and assessed by radiography, gait parameters, and histological and immunohistochemical analyses. EVs obtained from chondrocytes co-cultured with MSCs resulted in improved matrix production and functional differentiation. Our research showed that close proximity between the two cell types was essential for this response, and improved chondrogenesis and matrix formation were the outcomes of this interaction in vitro. Furthermore, in the in vivo rat OA model induced by a monoiodoacetate (MIA), we observed recovery from OA by increasing ratio of the C/M-derived EV group compared to the other groups. Our findings show that the increasing chondrocyte ratio to MSC leads to high chondrogenic induction and the therapeutic effect of harvested EVs for cartilage repair.

Human amniotic membrane extracellular matrix scaffold for dental pulp regeneration in vitro and in vivo.

AIM: In order to obtain a 3-dimentional scaffold with predictable clinical results for pulp regeneration, this study aims to fabricate and characterize a porous decellularized human amniotic membrane (HAM) extracellular matrix (ECM) scaffold, and evaluate its potential to promote pulp regeneration in vitro and in vivo. METHODOLOGY: The HAM was decellularized, and its histology and DNA content were analysed to confirm decellularization. The scaffolds were synthesized with 15, 22.5 and 30 mg/ml concentrations. The porosity, pore size, phosphate-buffered saline (PBS) absorption and degradation rate of the scaffolds were assessed. In vitro experiments were performed on human dental pulp stem cells (hDPSCs) to assess their viability, proliferation, adhesion and migration on the scaffolds. The optimal group was selected for in vivo immunogenicity assessment and was also used as the cell-free or cell-loaded scaffold in root segment models to evaluate pulp regeneration. All nonparametric data were analysed with the Kruskal-Wallis test followed by Dunn's post hoc test, whilst quantitative data were analysed with one-way anova. RESULTS: Decellularization of HAM was confirmed (p < .05). The porosity of all scaffolds was more than 95%, and the pore size decreased with an increase in ECM concentration (p < .01). PBS absorption was not significantly different amongst the groups, whilst 30 mg/ml ECM scaffold had the highest degradation rate (p < .01). The hDPSCs adhered to the scaffold, whilst their proliferation rate increased over time in all groups (p < .001). Cell migration was higher in 30 mg/ml ECM scaffold (p < .05). In vivo investigation with 30 mg/ml ECM scaffold revealed mild to moderate inflammatory response. In root segments, both cell-free and cell-loaded 30 mg/ml scaffolds were replaced with newly formed, pulp-like tissue with no significant difference between groups. Immunohistochemical assessments revealed high revascularization and collagen content with no significant difference amongst the groups. CONCLUSION: The 30 mg/ml HAM ECM scaffold had optimal physical properties and better supported hDPSC migration. The HAM ECM scaffold did not interfere with formation of pulp-like tissue and revascularization within the root canal when employed as both cell-free and cell-loaded scaffold. These results highlight the potential of HAM ECM membrane for further investigations in regenerative endodontics.

Role of bone 1stem cell-seeded 3D polylactic acid/polycaprolactone/hydroxyapatite scaffold on a critical-sized radial bone defect in rat.

Osteoconductive biomaterials were used to find the most reliable materials in bone healing. Our focus was on the bone healing capacity of the stem cell-loaded and unloaded PLA/PCL/HA scaffolds. The 3D scaffold of PLA/PCL/HA was characterized by scanning electron microscopy (SEM), rheology, X-ray diffraction (XRD), and Fourier transform-infrared (FT-IR) spectroscopy. Bone marrow stem cells (BMSCs) have multipotential differentiation into osteoblasts. Forty Wistar male rats were used to organize four experimental groups: control, autograft, scaffold, and BMSCs-loaded scaffold groups. qRT-PCR showed that the BMSCs-loaded scaffold had a higher expression level of CD31 and osteogenic markers compared with the control group (P < 0.05). Radiology and computed tomography (CT) scan evaluations showed significant improvement in the BMSCs-loaded scaffold compared with the control group (P < 0.001). Biomechanical estimation demonstrated significantly higher stress (P < 0.01), stiffness (P < 0.001), and ultimate load (P < 0.01) in the autograft and BMSCs-loaded scaffold groups compared with the untreated group and higher strain was seen in the control group than the other groups (P < 0.01). Histomorphometric and immunohistochemical (IHC) investigations showed significantly improved regeneration scores in the autograft and BMSCs-loaded scaffold groups compared with the control group (P < 0.05). Also, there was a significant difference between the scaffold and control groups in all tests (P < 0.05). The results depicted that our novel approach will allow to develop PLA/PCL/HA 3D scaffold in bone healing via BMSC loading.

Mesenchymal stem cells seeded onto tissue-engineered osteoinductive scaffolds enhance the healing process of critical-sized radial bone defects in rat.

Long bone defects comprise one of the most prevalent clinical problems worldwide and the current bone grafting materials have major limitations to repair them. Although tremendous efforts have been made to repair critical-sized long bone defects in animal models, designing an optimal bone tissue-engineered substitute remains one of the main challenges. Hence, this study aims to closely mimic a natural bone healing process by a tissue-engineered construct including osteoinductive materials pre-seeded with bone marrow-derived mesenchymal stem cells (BMSCs). Bioactive glass (BG) was incorporated into the gelatin/nano-hydroxyapatite (G/nHAp) scaffold (conventional one) to improve the bone regeneration process via its osteoinductivity and angiogenic activity. The fabricated G/nHAp and gelatin/nano-hydroxyapatite/bioactive glass (G/nHAp/BG) scaffolds were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) and analyzed for porosity and degradation rate. The osteogenic capability of fabricated scaffolds with or without BMSCs was then evaluated in vitro and in vivo. Critical-sized radial bone defects in rats were randomly filled with cell-free and BMSC-seeded scaffolds, autograft and a group left empty without any treatment. In vitro analysis showed that the G/nHAp/BG scaffold significantly increased the expression level of osteogenic and angiogenic markers in comparison to the G/nHAp-treated and control groups (P < 0.05). Moreover, the defects treated with the BMSC-seeded scaffolds showed superior bone formation and structural properties compared to the cell-free scaffolds 4 and 12 weeks post surgery. The radiological and histomorphological properties of defects treated by BMSC-seeded scaffolds, especially the BMSC-seeded G/nHAp/BG scaffold, were comparable to those of the autograft group. It is concluded that the combination of osteoconductive materials (i.e., nHAp) with the bioactive ones such as bioactive glass can effectively accelerate the bone regeneration process. In addition, our results demonstrated that the BMSCs have the potential to drastically increase the bone regeneration ability of osteoinductive scaffolds.

In vitro and in vivo investigation of PLA/PCL scaffold coated with metformin-loaded gelatin nanocarriers in regeneration of critical-sized bone defects.

Large bone defects constitute a major challenge in bone tissue engineering and usually fail to heal due to the incomplete differentiation of recruited mesenchymal stem cells (MSCs) into osteogenic precursor cells. As previously proposed, metformin (MET) induces differentiation of MSCs into osteoblastic lineages in vitro. We fabricated a Poly (lactic acid) and Polycaprolactone (PLA/PCL) scaffold to deliver metformin loaded gelatin nanocarriers (MET/GNs) to critical-sized calvarial bone defects in a rat model. The scaffolds were evaluated regarding their morphology, porosity, contact angle, degradation rate, blood compatibility, biomechanical, cell viability and their osteogenic differentiation. In animal study, the defects were filled with autograft, scaffolds and a group was left empty. qRT-PCR analyses showed the expression level of osteogenic and angiogenic markers considerably increased in MET/GNs-PLA/PCL. The in vivo results showed that MET/GNs-PLA/PCL improved bone ingrowth, angiogenesis and defect reconstruction. Our results represent the applicability of MET/GNs-PLA/PCL for successful bone regeneration.

Role of Mesenchymal Stem Cells in Bone Regenerative Medicine: What Is the Evidence?

Healing and regeneration of bone injuries, particularly those that are associated with large bone defects, are a complicated process. There is growing interest in the application of osteoinductive and osteogenic growth factors and mesenchymal stem cells (MSCs) in order to significantly improve bone repair and regeneration. MSCs are multipotent stromal stem cells that can be harvested from many different sources and differentiated into a variety of cell types, such as preosteogenic chondroblasts and osteoblasts. The effectiveness of MSC therapy is dependent on several factors, including the differentiating state of the MSCs at the time of application, the method of their delivery, the concentration of MSCs per injection, the vehicle used, and the nature and extent of injury, for example. Tissue engineering and regenerative medicine, together with genetic engineering and gene therapy, are advanced options that may have the potential to improve the outcome of cell therapy. Although several in vitro and in vivo investigations have suggested the potential roles of MSCs in bone repair and regeneration, the mechanism of MSC therapy in bone repair has not been fully elucidated, the efficacy of MSC therapy has not been strongly proven in clinical trials, and several controversies exist, making it difficult to draw conclusions from the results. In this review, we update the recent advances in the mechanisms of MSC action and the delivery approaches in bone regenerative medicine. We will also review the most recent clinical trials to find out how MSCs may be beneficial for treating bone defects.

Fabrication and characterization of a novel injectable human amniotic membrane hydrogel for dentin-pulp complex regeneration.

OBJECTIVE: Injectable biomaterials that can completely fill the root canals and provide an appropriate environment will have potential application for pulp regeneration in endodontics. This study aimed to fabricate and characterize a novel injectable human amniotic membrane (HAM) hydrogel scaffold crosslinked with genipin, enabling the proliferation of Dental Pulp Stem Cells (DPSCs) and optimizing pulp regeneration. METHODS: HAM extracellular matrix (ECM) hydrogels (15, 22.5, and 30 mg/ml) crosslinked with different genipin concentrations (0, 0.1, 0.5, 1, 5, and 10 mM) were evaluated for mechanical properties, tooth discoloration, cell viability, and proliferation of DPSCs. The hydrogels were subcutaneously injected in rats to assess their immunogenicity. The hydrogels were applied in a root canal model and subcutaneously implanted in rats to determine their regenerative potential for eight weeks, and histological and immunostaining analyses were performed. RESULTS: Hydrogels crosslinked with low genipin concentration demonstrated low tooth discoloration, but 0.1 mM genipin crosslinked hydrogels were excluded due to their unfavourable mechanical properties. The degradation ratio was lower in hydrogels crosslinked with 0.5 mM genipin. The 30 mg/ml-0.5 mM crosslinked hydrogel exhibited a microporous structure, and the modulus of elasticity was 1200 PA. In vitro, cell culture showed maximum viability and proliferation in 30 mg/ml-0.5 mM crosslinked hydrogel. All groups elicited minimum immunological responses, and highly vascularized pulp-like tissue was formed in human tooth roots in both groups with/without DPSCs. SIGNIFICANCE: Genipin crosslinking improved the biodegradability of injectable HAM hydrogels and conferred higher biocompatibility. Hydrogels encapsulated with DPSCs can support stem cell viability and proliferation. In addition, highly vascularized pulp-like tissue formation by this biomaterial displayed potential for pulp regeneration.

What are the risks accompanying the reduced wear benefit of low-clearance hip resurfacing?

BACKGROUND: Clearance is an important determinant of metal-metal bearing function. Tribologic theory and laboratory evidence suggest low clearance (LC) reduces wear but with a potential to increase friction and clinical reports show LC resurfacings have high implant failure rates. Thus, the role of LC is unclear. QUESTIONS/PURPOSES: We asked: is in vivo wear as reflected by cobalt (Co) and chromium (Cr) levels reduced in LC bearings, and if so, is this benefit offset by increased friction as assessed by implant-bone interface changes? METHODS: We retrospectively reviewed 26 patients with LC resurfacings. We assessed Co and Cr levels in blood and urine, hip function, and radiographic adverse features. These data were compared with those from 26 patients with a similar resurfacing but with conventional clearance (CC) from a previous study. Minimum followup was 4.0 years (mean, 4.1 years; range, 4.0-4.7 years). RESULTS: Co and Cr ion comparisons showed three phases: in the first 2 months, there was no difference between the cohorts; at 2 to 24 months, the CC group showed higher levels; and subsequently, levels in the two groups converged. A mean Oxford hip score of 13 and step activity of 1.9 million cycles per year in the LC group were similar to those of the CC group. Cup radiolucencies were seen in three patients in the LC group and none in the CC group. CONCLUSIONS: Lower Co and Cr levels suggest lower wear in the LC resurfacings in the intermediate term, but the presence of radiolucencies raises the concern that higher bearing friction is affecting implant fixation. A larger clearance than the theoretically predicted ideal may be required to allow for minor manufacturing imperfections, component deformation, and progressive changes in the in vivo lubricant. LEVEL OF EVIDENCE: Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

A discrete event simulation method for performance analysis of an additive manufacturing in the dental clinic.

Three-dimensional printing (3DP) is an evolutionary solution for making customize items for all sectors, but it has become more prominent in the healthcare sector. In this field, some solutions have to be adapted to patients. This is especially true for dentistry, where all the patients have their own unique mouth and tooth structure. It is now possible to provide an accurate model of the patient's mouth and teeth with solutions that are perfectly compatible with them, leading to the provision of a dental service with a high success rate. Even if there is a problem, it is enough to change the three-dimensional design. Therefore, it is a time-saving method, too. The purpose of this study is to investigate the role of 3DP in dentistry and to identify the processes and procedures resulting from the use of this technology. To do so, with the help of a case study, a 3DP-based dental clinic that provides implant, orthodontics, restoration and dentures services is simulated in Arena software. The current state of the system is assessed by defining appropriate evaluation criteria including net profit, utilization, waiting time, patients makespan and laboratory makespan. The simulation model is then developed with innovations such as adding an inventory control policy, creating rest time for resources and controlling the policy of sending products from laboratory to the clinic. After an extensive sensitivity analysis, improving the performance of the system is on the agenda of this paper by examining various scenarios. Results show that scenarios such as reducing some resources of the system or considering rest time in exchange for increasing the duration of the work shift can have a significant impact on clinic performance. Supplementary Information: The online version contains supplementary material available at 10.1007/s00170-021-08135-7.

Co-aggregation of MSC/chondrocyte in a dynamic 3D culture elevates the therapeutic effect of secreted extracellular vesicles on osteoarthritis in a rat model.

Extracellular vesicles (EVs) have therapeutic effects on osteoarthritis (OA). Some recent strategies could elevate EV's therapeutic properties including cell aggregation, co-culture, and 3D culture. It seems that a combination of these strategies could augment EV production and therapeutic potential. The current study aims to evaluate the quantity of EV yield and the therapeutic effect of EVs harvested from rabbit mesenchymal stem cells (MSCs) aggregates, chondrocyte aggregates, and their co-aggregates in a dynamic 3D culture in a rat osteoarthritis model. MSC and chondrocytes were aggregated and co-aggregated by spinner flasks, and their conditioned medium was collected. EVs were isolated by size exclusion chromatography and characterized in terms of size, morphology and surface markers. The chondrogenic potential of the MSC-ag, Cho-ag and Co-ag EVs on MSC micromass differentiation in chondrogenic media were assessed by qRT-PCR, histological and immunohistochemical analysis. 50 µg of MSC-ag-EVs, Cho-ag-EVs and Co-ag-EVs was injected intra-articularly per knee of OA models established by monoiodoacetate in rats. After 8 weeks follow up, the knee joints were harvested and analyzed by radiographic, histological and immunohistochemical features. MSC/chondrocyte co-aggregation in comparison to MSC or chondrocyte aggregation could increase EV yield during dynamic 3D culture by spinner flasks. Although MSC-ag-, Cho-ag- and Co-ag-derived EVs could induce chondrogenesis similar to transforming growth factor-beta during in vitro study, Co-ag-EV could more effectively prevent OA progression than MSC-ag- and Cho-ag-EVs. Our study demonstrated that EVs harvested from the co-aggregation of MSCs and chondrocytes could be considered as a new therapeutic potential for OA treatment.

Dexamethasone loaded injectable, self-healing hydrogel microspheresbased on UPy-functionalized Gelatin/ZnHAp physical network promotes bone regeneration.

Biopolymer-based injectable hydrogels provide great potential as bone tissue engineering (BTE) scaffolds on account of biocompatibility, and pore interconnectivity that enables delivery of cells and/or signaling molecules for bone repair. Recently, Gelatin hydrogels based on H-bonds were considered in response to concerns around the chemical crosslinking agents. In this study, a self-healing gelatin hydrogel with remarkable compressive and self-healing properties was prepared via formation of quadruple hydrogen bonds between ureidopyrimidinon functional groups, which were substituted on NH2 groups of gelatin(GelUPy). Degree of substitution controls properties of the resulting hydrogel from a shape- memory hydrogel (100% substitution), to a hydrogel (about 80%), to this self-healing hydrogel (about 40%). We report a strategy that adopts an emulsion synthesis approach to delivery of dexamethasone and Ca/Zn ions from injectable self-healing GelUPy hydrogel (GelUPy-ZnHApUPy-DEX), to induce osteogenic differentiation of adipose-derived stem cells, in vitro, and enhance bone regeneration in a cranial bone defect in a rat model. We show that key properties of the composite hydrogels, including mechanical properties, and release behavior of DEX are a match to the requirements of BTE. Overall, our results demonstrate that this self-healing gelatin approach is a promising strategy to enhance bone regeneration through a minimally invasive procedure.

Small molecules of herbal origin for osteoarthritis treatment: in vitro and in vivo evidence.

Osteoarthritis (OA) is one of the most common musculoskeletal degenerative diseases and contributes to heavy socioeconomic burden. Current pharmacological and conventional non-pharmacological therapies aim at relieving the symptoms like pain and disability rather than modifying the underlying disease. Surgical treatment and ultimately joint replacement arthroplasty are indicated in advanced stages of OA. Since the underlying mechanisms of OA onset and progression have not been fully elucidated yet, the development of novel therapeutics to prevent, halt, or reverse the disease is laborious. Recently, small molecules of herbal origin have been reported to show potent anti-inflammatory, anti-catabolic, and anabolic effects, implying their potential for treatment of OA. Herein, the molecular mechanisms of these small molecules, their effect on physiological or pathological signaling pathways, the advancement of the extraction methods, and their potential clinical translation based on in vitro and in vivo evidence are comprehensively reviewed.

Standard toxicity study of clinical-grade allogeneic human bone marrow-derived clonal mesenchymal stromal cells.

INTRODUCTION: Mesenchymal stromal cells (MSCs) have opened a new window to treat inflammatory and non-inflammatory diseases. Nonetheless, their clinical applications require rigorous control and monitoring procedures to ensure full compliance with the principles of good manufacturing practice (GMP). Various evaluations should be passed in conjunction with the development of these newly emerging therapeutic products from bench-to-bedside. These evaluations include in vitro characterization, preclinical studies, and clinical trials to ensure product safety and efficacy. Therefore, a robust and well-designed preclinical study is critical to confirm product safety. This study aims to determine the probable toxicity effects of local and systemic injections of cryopreserved human bone marrow-derived clonal MSCs (BM-cMSCs) during subacute and subchronic periods of time. METHODS: BM-cMSCs were characterized according to the International Society for Cell and Gene Therapy (ISCT) criteria for MSCs. Both safety and toxicity of the BM-cMSCs population produced under GMP-compatible conditions were assessed in both sexes of Sprague Dawley (SD) rats via systemic intravenous (IV) administration and local injection in intervertebral disc (IVD). Behavioral changes, clinical signs of toxicity, and changes in body weight, water and food consumption were the important variables for product toxicity testing over 14 consecutive days during the subacute period and 90 consecutive days during the subchronic period. At the end of the assessment periods, the rats were killed for histopathology analysis of the target tissues. The BM-cMSCs potential for tumorigenicity was checked in nude mice. RESULTS: Single IV and IVD injections of BM-cMSCs did not cause significant signs of clinical toxicity, or changes in laboratory and histopathology data during the subacute (14 day) and subchronic (90 day) periods. Ex vivo-expanded and cryopreserved BM-cMSCs did not induce tumor formation in nude mice. CONCLUSION: The results suggest that local and systemic administrations of xenogeneic BM-cMSCs in both sexes of SD rats do not cause toxicity during the subacute and subchronic periods of time. Also, BM-cMSCs were non-tumorigenic in nude mice.

Long-term passages of human clonal mesenchymal stromal cells can alleviate the disease in the rat model of collagen-induced arthritis resembling early passages of different heterogeneous cells.

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease of unknown cause. The interaction of immune system cells and the secretion of inflammatory cytokines with synovial cells leads to severe inflammation in the affected joints. Currently, medications, including non-steroidal anti-inflammatory drugs, glucocorticoids, and more recently, disease-modifying anti-rheumatic drugs, are used to reduce inflammation. However, long-term use of these drugs causes adverse effects or resistance in a considerable number of RA patients. Recent findings revealed the safety and efficacy of mesenchymal stromal cells (MSCs)-based therapies both in RA animal models and clinical trials. Here, the beneficial effects of bone marrow-derived heterogeneous MSCs (BM-hMSCs) and Wharton jelly-derived MSCs (WJ-MSCs) at early passages were compared to BM-derived clonal MSCs (BM-cMSCs) at high passage number on a rat model of collagen-induced arthritis. Results showed that systemic delivery of MSCs significantly reversed adverse changes in body weight, paw swelling, and arthritis score in all MSC-treated groups. Radiological images and histological evaluation demonstrated the therapeutic effects of MSCs. There was a decrease in serum level of anti-collagen type II immunoglobulin G and the inflammatory cytokines interleukin (IL)-1ß, IL-6, IL-17, and tumor necrosis factor-α in all MSC-treated groups. In contrast, an increase in inhibitory cytokines transforming growth factor-ß and IL-10 was seen. Notably, the long-term passages of BM-cMSCs could alleviate RA symptoms similar to the early passages of WJ-MSCs and BM-hMSCs. The importance of BM-cMSCs is the potential to establish cell banks with billions of cells derived from a single donor that could be a competitive cell-based therapy to treat RA.

Higher Chondrogenic Potential of Extracellular Vesicles Derived from Mesenchymal Stem Cells Compared to Chondrocytes-EVs In Vitro.

The inability of cartilage to self-repair necessitates an effective therapeutic approach to restore damaged tissues. Extracellular vesicles (EVs) are attractive options because of their roles in cellular communication and tissue repair where they regulate the cellular processes of proliferation, differentiation, and recruitment. However, it is a challenge to determine the relevant cell sources for isolation of EVs with high chondrogenic potential. The current study aims to evaluate the chondrogenic potential of EVs derived from chondrocytes (Cho-EV) and mesenchymal stem cells (MSC-EV). The EVs were separately isolated from conditioned media of both rabbit bone marrow MSCs and chondrocyte cultures. The isolated vesicles were assessed in terms of size, morphology, and surface marker expression. The chondrogenic potential of MSCs in the presence of different concentrations of EVs (50, 100, and 150 µg/ml) was evaluated during 21 days, and chondrogenic surface marker expressions were checked by qRT-PCR and histologic assays. The extracted vesicles had a spherical morphology and a size of 44.25 ± 8.89 nm for Cho-EVs and 112.1 ± 10.10 nm for MSC-EVs. Both groups expressed the EV-specific surface markers CD9 and CD81. Higher expression of chondrogenic specified markers, especially collagen type II (COL II), and secretion of glycosaminoglycans (GAGs) and proteoglycans were observed in MSCs treated with 50 and 100 µg/ml MSC-EVs compared to the Cho-EVs. The results from the use of EVs, particularly MSC-EVs, with high chondrogenic ability will provide a basis for developing therapeutic agents for cartilage repair.

Reduced Risk of Revision with Computer-Guided Versus Non-Computer-Guided THA: An Analysis of Manufacturer-Specific Data from the National Joint Registry of England, Wales, Northern Ireland and the Isle of Man.

Computer-assisted total hip arthroplasty (THA) is known to improve implantation precision, but clinical data demonstrating an improvement in survivorship and patient-reported outcome measures (PROMs) are lacking. Our aim was to compare the risk of revision, PROMs, and patient satisfaction between cohorts who underwent THA with and without the use of computer guidance. METHODS: We used the data set and linked PROM data of the National Joint Registry of England, Wales, Northern Ireland and the Isle of Man. Our sample included THAs performed for osteoarthritis using cementless acetabular components from a single manufacturer (cementless and hybrid THAs). An additional analysis was performed limiting the sample size to cementless-only THAs. The primary end point was revision (any component) for any reason. Kaplan-Meier survivorship analysis and an adjusted Cox proportional-hazards model were used. RESULTS: There were 41,683 non-computer-guided and 871 (2%) computer-guided cases included in our analysis of the cementless and hybrid group. There were 943 revisions in the non-computer-guided group and 7 in the computer-guided group. The cumulative revision rate at 10 years was 3.88% (95% confidence interval [CI]: 3.59% to 4.18%) for the non-computer-guided group and 1.06% (95% CI: 0.45% to 2.76%) for the computer-guided group. The Cox proportional-hazards model yielded a hazard ratio of 0.45 (95% CI: 0.21 to 0.96; p = 0.038). In the analysis of the cementless-only group, the cumulative revision rate at 10 years was 3.99% (95% CI: 3.62% to 4.38%) and 1.20% (95% CI: 0.52% to 3.12%) for the 2 groups, respectively. The Cox proportional-hazards model yielded a hazard ratio of 0.47 (95% CI: 0.22 to 1.01; p = 0.053). There was no significant difference in the 6-month Oxford Hip Score, the EuroQol-5 Dimension (EQ-5D) and EQ-VAS (Visual Analogue Scale) scores, and patient-reported success rates. Patient satisfaction (single-item satisfaction outcome measure) was higher in the computer-guided group, but this finding was limited by a reduced number of responses. CONCLUSIONS: In our analysis, the use of computer-guided surgery was associated with a lower rate of revision at mean follow-up of 5.6 years. This finding was upheld when the sample was restricted to cementless-only THAs. Causality cannot be inferred in view of the observational nature of the study, and additional studies are recommended to validate these findings. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Small molecule-based treatment approaches for intervertebral disc degeneration: Current options and future directions.

Low back pain (LBP) is a major reason for disability, and symptomatic intervertebral disc (IVD) degeneration (IDD) contributes to roughly 40% of all LBP cases. Current treatment modalities for IDD include conservative and surgical strategies. Unfortunately, there is a significant number of patients in which conventional therapies fail with the result that these patients remain suffering from chronic pain and disability. Furthermore, none of the current therapies successfully address the underlying biological problem - the symptomatic degenerated disc. Both spinal fusion as well as total disc replacement devices reduce spinal motion and are associated with adjacent segment disease. Thus, there is an unmet need for novel and stage-adjusted therapies to combat IDD. Several new treatment options aiming to regenerate the IVD are currently under investigation. The most common approaches include tissue engineering, growth factor therapy, gene therapy, and cell-based treatments according to the stage of degeneration. Recently, the regenerative activity of small molecules (low molecular weight organic compounds with less than 900 daltons) on IDD was demonstrated. However, small molecule-based therapy in IDD is still in its infancy due to limited knowledge about the mechanisms that control different cell signaling pathways of IVD homeostasis. Small molecules can act as anti-inflammatory, anti-apoptotic, anti-oxidative, and anabolic agents, which can prevent further degeneration of disc cells and enhance their regeneration. This review pursues to give a comprehensive overview of small molecules, focusing on low molecular weight organic compounds, and their potential utilization in patients with IDD based on recent in vitro, in vivo, and pre-clinical studies.

Optimizing Methods for Bovine Dental Pulp Decellularization.

INTRODUCTION: This study aimed to characterize the decellularization effects of different treatment protocols on the bovine dental pulp extracellular matrix (ECM) for tissue regeneration. METHODS: Seven different decellularization protocols consisting of trypsin/EDTA (for 1 hour, 24 hours, or 48 hours), sodium dodecyl sulfate (SDS, for 24 hours or 48 hours), Triton X-100 (for 1 hour), and deoxyribonuclease treatments were tested on bovine dental pulp tissue. The posttreatment samples were evaluated for remaining DNA and cellular contents, structural durability, immunofluorescence analysis, and in vivo immune responses. RESULTS: A complete decellularization process in all of the experimental groups was observed. The protocol that included 1 hour of Triton X-100 treatment and 12 hours of trypsin/EDTA treatment with no SDS treatment (P7 [12E-0S-1T]) showed the highest retention of glycosaminoglycan and the absence of nuclei in 4,6-diamidino-2-phenylindole. All groups showed significantly lower DNA content compared with native pulp tissue (P < .05), whereas compared with other protocols, protocols 1 (1 hour of EDTA/trypsin, 24 hours of SDS, and 1 hour of Triton X-100) and 4 (1 hour of EDTA/Trypsin, 48 hours of SDS, and no Triton X-100) resulted in the highest DNA contents (P < .05). Based on these results, P7 was further evaluated by immunofluorescence and in vivo immunogenicity. P7 specimens preserved collagen type I, whereas mononuclear cell infiltration along with neovascularization was observed in vivo. CONCLUSIONS: All tested treatments displayed the potential ability to decellularize pulp tissue and are viable options for a xenogeneic dental pulp ECM scaffold. The P7 (12E-0S-1T) protocol resulted in decellularized ECM with minimal organic matrix/ultrastructural detriments and an acceptable host immune response.

Uncovering the secretome of mesenchymal stromal cells exposed to healthy, traumatic, and degenerative intervertebral discs: a proteomic analysis.

BACKGROUND: Mesenchymal stromal cells (MSCs) have been introduced as promising cell source for regenerative medicine. Besides their multilineage differentiation capacity, MSCs release a wide spectrum of bioactive factors. This secretome holds immunomodulatory and regenerative capacities. In intervertebral disc (IVD) cells, application of MSC secretome has been shown to decrease the apoptosis rate, induce proliferation, and promote production of extracellular matrix (ECM). For clinical translation of secretome-based treatment, characterization of the secretome composition is needed to better understand the induced biological processes and identify potentially effective secretomes. METHODS: This study aimed to investigate the proteome released by bone marrow-derived MSCs following exposure to a healthy, traumatic, or degenerative human IVD environment by mass spectroscopy and quantitative immunoassay analyses. Exposure of MSCs to the proinflammatory stimulus interleukin 1ß (IL-1ß) was used as control. RESULTS: Compared to MSC baseline secretome, there were 224 significantly up- or downregulated proteins following healthy, 179 following traumatic, 223 following degenerative IVD, and 160 proteins following IL-1ß stimulus. Stimulation of MSCs with IVD conditioned media induced a more complex MSC secretome, involving more biological processes, compared to stimulation with IL-1ß. The MSC response to stimulation with IVD conditioned medium was dependent on their pathological status. CONCLUSIONS: The MSC secretome seemed to match the primary need of the IVD: homeostasis maintenance in the case of healthy IVDs, versus immunomodulation, adjustment of ECM synthesis and degradation disbalance, and ECM (re) organization in the case of traumatic and degenerative IVDs. These findings highlight the importance of cell preconditioning in the development of tailored secretome therapies. The secretome of human bone marrow-derived mesenchymal stromal cells (MSCs) stimulated with intervertebral disc (IVD) conditioned medium was analyzed by proteomic profiling. Depending on the pathological state of the IVD, the MSC secretome protein composition indicated immunomodulatory or anabolic activity of the secretome. These findings may have implications for tailored secretome therapy for the IVD and other tissues.