Biomechanical evaluation of different medial column fixation patterns for valgus pilon fractures.

BACKGROUND: The purpose of this study was to perform a biomechanical analysis to compare different medial column fixation patterns for valgus pilon fractures in a case-based model. METHODS: Based on the fracture mapping, 48 valgus pilon fracture models were produced and assigned into four groups with different medial column fixation patterns: no fixation (NF), K-wires (KW), intramedullary screws (IS), and locking compression plate (LCP). Each group contained wedge-in and wedge-out subgroups. After fixing each specimen on the machine, gradually increased axial compressive loads were applied with a load speed of one millimeter per minute. The maximum peak force was set at 1500 N. Load-displacement curves were generated and the axial stiffness was calculated. Five different loads of 200 N, 400 N, 600 N, 800 N, 1000 N were selected for analysis. The specimen failure was defined as resultant loading displacement over 3 mm. RESULTS: For the wedge-out models, Group-IS showed less displacement (p < 0.001), higher axial stiffness (p < 0.01), and higher load to failure (p < 0.001) than Group-NF. Group-KW showed comparable displacement under loads of 200 N, 400 N and 600 N with both Group-IS and Group-LCP. For the wedge-in models, no statistical differences in displacement, axial stiffness, or load to failure were observed among the four groups. Overall, wedge-out models exhibited less axial stiffness than wedge-in models (all p < 0.01). CONCLUSIONS: Functional reduction with stable fixation of the medial column is essential for the biomechanical stability of valgus pilon fractures and medial column fixation provides the enough biomechanical stability for this kind of fracture in the combination of anterolateral fixation. In detail, the K-wires can provide a provisional stability at an early stage. Intramedullary screws are strong enough to provide the medial column stability as a definitive fixation. In future, this technique can be recommended for medial column fixation as a complement for holistic stability in high-energy valgus pilon fractures.

SPARCL1 promotes chondrocytes extracellular matrix degradation and inflammation in osteoarthritis via TNF/NF-κB pathway.

Objectives: SPARCL1 is a matricellular protein that mediates the cell-matrix interactions and participates in physiological processes such as cell adhesion, differentiation and proliferation. However, its role in chondrocyte and osteoarthritis (OA) progression has not been fully characterized. We aimed to evaluate the effects of SPARCL1 on OA through in vitro and in vivo experiments. Methods: Expression of SPARCL1 was examined in 55 paired human OA samples. Effects of Sparcl1 on chondrocytes were identified in vitro. Intra-articular injection was performed in an anterior cruciate ligament transection (ACLT) mouse model. Alterations of SPARCL1-mediated signaling pathway were identified by RNA-seq analysis. qPCR and western-blot were used to demonstrate the potential signaling pathway. Results: SPARCL1 expression in the OA cartilage was increased compared with undamaged cartilage. Recombinant Sparcl1 protein induced extracellular matrix degradation in chondrocytes. Furthermore, intra-articular injection of recombinant Sparcl1 protein in ACLT mice could promote OA pathogenesis. Mechanistically, Sparcl1 activated TNF/NF-κB pathway and consequently led to increased transcription of inflammatory factors and catabolism genes of cartilage, which could be reversed by NF-κB inhibitor BAY 11-7082. Conclusion: SPARCL1 could promote extracellular matrix degradation and inflammatory response to accelerate OA progression via TNF/NF-κB pathway. The translational potential of this article: The current research could help to gain further insights into the underlying molecular mechanism in OA development, and provides a biological rationale for the use of SPARCL1 as a potential therapeutic target of OA.

1,3,5-triazines inhibit osteosarcoma and avert lung metastasis in a patient-derived orthotopic xenograft mouse model with favorable pharmacokinetics.

Objectives: Osteosarcoma is a major solid malignant tumor of bone, possessing significant burden on healthcare due to non-availability of specific anticancer agents. The current study was conducted to identify novel 1,3,5-triazine derivatives against osteosarcoma. Materials and Methods: The compounds were synthesized in a straight-forward two-step reaction and subsequently tested against PI3K and mTOR kinase and anticancer activity against osteosarcoma cells (MG-63, U2-OS, and Saos-2). The effect of the most potent compound was evaluated on apoptosis and cell phase of Saos-2 cells. The pharmacological activity was further established in the patient-derived orthotopic xenograft (PDOX) mouse model. Results: The developed compounds 8 (a-f) showed significant inhibitory activities against PI3K, mTOR, and OS cells. Among the tested series, compound 8a showed highly potent PI3K/mTOR inhibitory activity with significant anticancer activity against Saos-2 cells compared with Imatinib as standard. It also induces apoptosis and causes G2/M arrest in Saos-2 cells. Compound 8a significantly improved body weight, reduced tumor volume, and inhibited lung metastasis in athymic nude mice in a PDOX mouse model. It also showed optimal pharmacokinetic parameters in SD rats. Conclusion: In summary, 1,3,5-triazine analogs were identified as new PI3K/mTOR inhibitors against osteosarcoma.

Novel 1,3,5-triazine-nicotinohydrazide derivatives induce cell arrest and apoptosis in osteosarcoma cancer cells and inhibit osteosarcoma in a patient-derived orthotopic xenograft mouse model.

The present study deals with developing novel 1,3,5-triazine-nicotinohydrazide derivatives as potent CDK9 inhibitors in a straightforward synthetic route with potent anti-osteosarcoma activity. The most potent CDK9 inhibitor compound 5k inhibits proliferation of MG-63 cells via induction of apoptosis and G2/M cell cycle arrest. It reduces tumor progression in the patient-derived orthotopic xenograft (PDOX) mouse model with significant antioxidant and anti-inflammatory activity. In tumor tissue homogenates, it caused significant inhibition of CDK9 and inhibited the phosphorylation of RNAPII ser2 and reduced MCL-1 expression in Western blot analysis. Compound 5k also showed considerable bioavailability in SD mice. Our results demonstrated that compound 5k inhibits growth of OS in vitro and in vivo via inhibition of CDK9 which attenuated the downstream phosphorylation of RNAPII ser2 and represses expression of the anti-apoptotic protein, MCL-1 for the induction of apoptosis in OS.

Design and development of novel 1,2,3-triazole chalcone derivatives as potential anti-osteosarcoma agents via inhibition of PI3K/Akt/mTOR signalling pathway.

Osteosarcoma (OS) is an uncommon tumour that mainly affects bone in children and adolescents. The current treatment options of OS are of limited significance due to their immense side effects. In the present manuscript, we have developed a novel series of 1,2,3-triazole chalcone derivatives as potential agents against OS. The compounds were synthesized and evaluated for their PI3K and mTOR inhibitory activity using luminescent kinase assay, and Lance ultra assay, resp. The entire set of compounds showed significant to moderate inhibition of both kinases in the nanomolar range. The three most active compounds: 4e (N-(4-(3-(1-(4-bromophenyl)-1H-1,2,3-triazol-4-yl)acryloyl)phenyl)-4-nitrobenzamide), 4f (N-(4-(3-(1-(4-bromophenyl)-1H-1,2,3-triazol-4-yl)acryloyl)phenyl)-4-chlorobenzamide) and 4g (4-bromo-N-(4-(3-(1-(4-bromophenyl)-1H-1,2,3-triazol-4-yl)acryloyl)phenyl)benzamide), were evaluated for anticancer activity against human OS cancer cell line (MG-63), liver cancer cell line (HepG2), lung cancer cell line (A549) and cervical cancer (HeLa), using MTT assay. Among the tested series, compound 4e showed a better inhibitory profile than gedatolisib against PI3K and was approximately comparable to that of gedatolisib against mTOR. The most significant inhibitory activity was observed for compound 4e against all cell lines (MG-63, HepG2, A549 and HeLa), still somewhat lower to comparable to that of gedatolisib, but with the highest potency against MG-63 cells. Compound 4e was further tested for anti-cancer activity against other OS cells and showed to be equipo-tent to gedatolisib against U2OS and Saos-2 cells. Moreover, it was also found non-toxic to normal cells (BEAS-2B and MCF 10A). The effect of compound 4e was further determined on apoptosis of Saos-2 cells by Annexin-PI assay, where it significantly amplified the percentage of apoptotic cells. Novel 1,2,3-triazole chalcone derivatives are potential agents against OS.