Lithium protects against cartilage degradation in osteoarthritis

Lithium rescues cultured rat metatarsals from dexamethasone-induced growth failure

BACKGROUND

Glucocorticoids are commonly used in children with different chronic diseases. Growth failure represents a so far untreatable undesired side-effect. As lithium chloride (LiCl) is known to induce cell renewal in various tissues, we hypothesized that LiCl may prevent glucocorticoid-induced growth failure.

METHODS

We monitored growth of fetal rat metatarsals cultured ex-vivo with dexamethasone and/or LiCl, while molecular mechanisms were explored through RNA sequencing by implementing the differential gene expression and gene set analysis. Quantification of β-catenin in human growth plate cartilage cultured with dexamethasone and/or LiCl was added for verification.

RESULTS

After 14 days of culture, the length of dexamethasone-treated fetal rat metatarsals increased by 1.4 ± 0.2 mm compared to 2.4 ± 0.3 mm in control bones (p < 0.001). The combination of LiCl and dexamethasone led to bone length increase of 1.9 ± 0.3 mm (p < 0.001 vs. dexamethasone alone). By adding lithium, genes for cell cycle and Wnt/β-catenin, Hedgehog and Notch signaling, were upregulated compared to dexamethasone alone group.

CONCLUSIONS

LiCl has the potential to partially rescue from dexamethasone-induced bone growth impairment in an ex vivo model. Transcriptomics identified cell renewal and proliferation as candidates for the underlying mechanisms. Our observations may open up the development of a new treatment strategy for bone growth disorders.

IMPACT

LiCl is capable to prevent glucocorticoid-induced growth failure in rat metatarsals in vitro. The accompanying drug-induced transcriptomic changes suggested cell renewal and proliferation as candidate underlying mechanisms. Wnt/beta-catenin pathway could be one of those novel mechanisms.

Surface-modified titanium and titanium-based alloys for improved osteogenesis: A critical review

As implantable materials, titanium, and its alloys have garnered enormous interest from researchers for dental and orthopedic procedures. Despite their success in wide clinical applications, titanium, and its alloys fail to stimulate osteogenesis, resulting in poor bonding strength with surrounding bone tissue. Optimizing the surface topology and altered compositions of titanium and titanium-based alloys substantially promotes peri-implant bone regeneration. This review summarizes the utilization and importance of various osteogenesis components loaded onto titanium and its alloys. Further, different surface-modification methods and the release efficacy of loaded substances are emphasized. Finally, we summarize the article with prospects. We believe that further investigation studies must focus on identifying novel loading components, exploring various innovative, optimized surface-modification methods, and developing a sustained-release system on implant surfaces to improve peri-implant bone formation.

The exosomal secretomes of mesenchymal stem cells extracted via 3D-printed lithium-doped calcium silicate scaffolds promote osteochondral regeneration

The development of surface modification techniques has brought about a major paradigm shift in the clinical applications of bone tissue regeneration. Biofabrication strategies enable the creation of scaffolds with specific microstructural environments and biological components. Lithium (Li) has been reported to exhibit anti-inflammatory, osteogenic, and chondrogenic properties by promoting several intracellular signaling pathways. Currently, research focuses on fabricating scaffolds with simultaneous dual bioactivities to enhance osteochondral regeneration. In this study, we modified the surface of calcium silicate (CS) scaffolds with Li using a simple immersion technique and evaluated their capabilities for bone regeneration. The results showed that Li ions could be easily coated onto the surfaces of CS scaffolds without affecting the microstructural properties of CS itself. Furthermore, the modifications did not affect the printing capabilities of the CS, and porous scaffolds could be fabricated via extrusion. Moreover, the presence of Li improved the surface roughness and hydrophilicity, thus leading to enhanced secretion of osteochondral-related regeneration factors, such as alkaline phosphatase (ALP), bone sialoprotein (BSP), and collagen II (Col II) proteins. Subsequent in vivo studies, including histological and micro-CT analyses, confirmed that the Li-modified CS scaffolds promoted osteochondral regeneration. The transcriptome analysis suggested that the enhanced osteochondrogenic capabilities of our scaffolds were influenced by paracrine exosomes. We hope this study will inspire further research on osteochondral regeneration.

Lithium-Containing Biomaterials Stimulate Cartilage Repair through Bone Marrow Stromal Cells-Derived Exosomal miR-455-3p and Histone H3 Acetylation

The repair of damaged cartilage still remains a great challenge in clinic. It is demonstrated that bone marrow stromal cells (BMSCs)-chondrocytes communication is of great significance for cartilage repair. Moreover, BMSCs have been confirmed to enhance biological function of chondrocytes via exosome-mediated paracrine pathway. Lithium-containing scaffolds have been reported to effectively promote cartilage regeneration; however, whether lithium-containing biomaterial could facilitate cartilage regeneration through regulating BMSCs-derived exosomes has not been illustrated. In the study, the model lithium-substituted bioglass ceramic (Li-BGC) is selected and regulatory effects of BMSCs-derived exosomes after Li-BGC treatment (Li-BGC-Exo) are systemically evaluated. The data reveal that Li-BGC-Exo notably promotes chondrogenesis, which attributes to the upregulated exosomal miR-455-3p transfer, consequently leads to suppression of histone deacetylase 2 (HDAC2) and enhanced histone H3 acetylation in chondrocytes. Notably, BMSCs-derived exosomes after LiCl treatment (LiCl-Exo) exhibits the similar regulatory effect with Li-BGC-Exo, indicating that the pro-chondrogenesis capability of them is mainly owing to the lithium ions. Furthermore, the in vivo study proves that LiCl-Exo remarkably facilitates cartilage regeneration. The research may provide novel possibility for the intrinsic mechanism of chondrogenesis trigged by lithium-containing biomaterials, and suggests that application of lithium-containing scaffolds may be a promising strategy for cartilage regeneration.

Li-Doped Ti Surface for the Improvement of Osteointegration

Aseptic loosening is the main factor that leads to the failure of orthopedic implants. Enhancing the early osteointegration of a bone implant can lower the risk of aseptic loosening. Here, a Li-doped surface was constructed on a Ti surface via plasma electrolytic oxidation (PEO) to improve osteointegration. The prepared Li-doped PEO coating showed a porous morphology and the sustained release of Li ions. In vitro results of rat bone marrow mesenchymal stem cell (rBMSC) culture studies suggested that the Li-doped Ti surface significantly favored cell adhesion. Moreover, it was found that the Li-doped surface enhanced alkaline phosphatase activity and extracellular matrix mineralization of rBMSCs. In addition, the surface improved the expression of osteogenesis-related genes. Furthermore, a bone implantation model indicated that the Li-doped Ti surface showed improved osteointegration. The incorporation of Li into a Ti surface is a promising method for orthopedic applications.

miR-122 and the WNT/β-catenin pathway inhibit effects of both interleukin-1β and tumor necrosis factor-α in articular chondrocytes in vitro

Interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and WNT/β-catenin signaling cause dysregulation of rat primary articular chondrocytes (rArCs), resulting in cartilage extracellular matrix destruction and osteoarthritis (OA) progression. microRNA (miR) miR-122 represses these effects whereas miR-451 exacerbates IL-1β-stimulated matrix metalloproteinase-13 (MMP-13) and prostaglandin E2 (PGE2) production. The goals of this study were to evaluate crosstalk between these signaling pathways and determine if miR-122 and miR-451 exert their protective/destructive effects through these pathways in an in vitro model of OA. Primary rArCs were treated with IL-1β or TNF-α for 24 h and total DNA, MMP-13, and PGE2, as well as expression levels of miR-122 and miR-451 were measured. After 24-h transfection with miR-122, miR-451, miR-122-inhibitor, or miR-451-inhibitor, rArCs were treated with or without TNF-α for 24 h; total DNA, MMP-13, and PGE2 were measured. Similarly, cells were treated with WNT-agonist lithium chloride (LiCl), WNT-antagonist XAV-939 (XAV), or PKF-118-310 (PKF) with and without IL-1β or TNF-α stimulation. Both IL-1β and TNF-α-stimulation increased MMP-13 and PGE2 production. Transfection with miR-122 prevented TNF-α-stimulated increases in MMP-13 and PGE2 whereas transfection with miR-451 did not change these levels. No differences were found in MMP-13 or PGE2 production with miR-122 or miR-451 inhibitors. LiCl treatment decreased PGE2 production in cultures treated with TNF-α, but not MMP-13. XAV increased TNF-α-stimulated increases in PGE2 but not MMP-13. LiCl reduced IL-1β-stimulated increases in MMP-13 and PGE2. XAV and PKF increased IL-1β-stimulated increases in MMP-13 and PGE2. In this in vitro OA model, miR-122 protects against both IL-1β and TNF-α stimulated increases in MMP-13 and PGE2 production. miR-451 does not act through the TNF-α pathway. The WNT/β-catenin pathway regulates the effects of IL-1β and TNF-α stimulation. This study suggests that miR-122 can be used as a treatment or prevention for OA.

Exosomes derived from platelet-rich plasma administration in site mediate cartilage protection in subtalar osteoarthritis

Subtalar osteoarthritis (STOA) is often secondary to chronic ankle sprains, which seriously affects the quality of life of patients. Due to its etiology and pathogenesis was not studied equivocally yet, there is currently a lack of effective conservative treatments. Although they have been used for tissue repair, platelet-rich plasma-derived exosomes (PRP-Exo) have the disadvantage of low retention and short-lived therapeutic effects. This study aimed to determine whether incorporation of PRP-Exo in thermosensitive hydrogel (Gel) increased their retention in the joint and thereby playing a therapeutic role on STOA due to chronic mechanical instability established by transecting lateral ligaments (anterior talofibular ligament (ATFL)/calcaneal fibular ligament (CFL)). PRP-Exo incorporated Gel (Exo-Gel) system, composed of Poloxamer-407 and 188 mixture-based thermoresponsive hydrogel matrix in an optimal ratio, was determined by its release ability of Exo and rheology of Gel response to different temperature. The biological activity of Exo-Gel was evaluated in vitro, and the therapeutic effect of Exo-Gel on STOA was evaluated in vivo. Exo released from Exo-Gel continuously for 28 days could promote the proliferation and migration of mouse bone mesenchymal stem cells (mBMSCs) and chondrocytes, at the same time enhance the chondrogenic differentiation of mBMSCs, and inhibit inflammation-induced chondrocyte degeneration. In vivo experiments confirmed that Exo-Gel increased the local retention of Exo, inhibited the apoptosis and hypertrophy of chondrocytes, enhanced their proliferation, and potentially played the role in stem cell recruitment to delay the development of STOA. Thus, Delivery of PRP-Exo incorporated in thermosensitive Gel provides a novel approach of cell-free therapy and has therapeutic effect on STOA.

Graphical Abstract

Effects of lithium administration on vertebral bone disease in mucopolysaccharidosis I dogs

Mucopolysaccharidosis (MPS) I is a lysosomal storage disease characterized by deficient activity of the enzyme alpha-L-iduronidase, leading to abnormal accumulation of heparan and dermatan sulfate glycosaminoglycans in cells and tissues. Patients commonly exhibit progressive skeletal abnormalities, in part due to failures of endochondral ossification during postnatal growth. Previously, using the naturally-occurring canine model, we showed that bone and cartilage cells in MPS I exhibit elevated lysosomal storage from an early age and that animals subsequently exhibit significantly diminished vertebral trabecular bone formation. Wnts are critical regulators of endochondral ossification that depend on glycosaminoglycans for signaling. The objective of this study was to examine whether lithium, a glycogen synthase kinase-3 inhibitor and stimulator of Wnt/beta-catenin signaling, administered during postnatal growth could attenuate progression of vertebral trabecular bone disease in MPS I. MPS I dogs were treated orally with therapeutic levels of lithium carbonate from 14 days to 6 months-of-age. Untreated heterozygous and MPS I dogs served as controls. Serum was collected at 3 and 6 months for assessment of bone turnover markers. At the study end point, thoracic vertebrae were excised and assessed using microcomputed tomography and histology. Lithium-treated animals exhibited significantly improved trabecular spacing, number and connectivity density, and serum bone-specific alkaline phosphatase levels compared to untreated animals. Growth plates from lithium-treated animals exhibited increased numbers of hypertrophic chondrocytes relative to both untreated MPS I and heterozygous animals. These findings suggest that bone and cartilage cells in MPS I are still capable of responding to exogenous osteogenic signals even in the presence of significant lysosomal storage, and that targeted osteogenic therapies may represent a promising approach for attenuating bone disease progression in MPS I.

Hyperosmolar Ionic Solutions Modulate Inflammatory Phenotype and sGAG Loss in a Cartilage Explant Model

OBJECTIVE

The objective of this study was to compare the effects of hyperosmolar sodium (Na+), lithium (Li+) and potassium (K+) on catabolic and inflammatory osteoarthritis (OA) markers and sulfated glycosaminoglycan (sGAG) loss in TNF-α-stimulated cartilage explants.

METHODS

Explants from bovine stifle joints were stimulated with TNF-α for 1 day to induce cartilage degradation followed by supplementation with 50 mM potassium chloride (KCl), 50 mM lithium chloride (LiCl), 50 mM sodium chloride (NaCl), or 100 nM dexamethasone for an additional 6 days. We assessed the effect of TNF-α stimulation and hyperosmolar ionic treatment on sGAG loss and expression of OA-associated proteins: ADAMTS-5, COX-2, MMP-1, MMP-13, and VEGF.

RESULTS

TNF-α treatment increased sGAG loss (P < 0.001) and expression of COX-2 (P = 0.018), MMP-13 (P < 0.001), and VEGF (P = 0.017) relative to unstimulated controls. Relative to activated controls, LiCl and dexamethasone treatment attenuated sGAG loss (P = 0.008 and P = 0.042, respectively) and expression of MMP-13 (P = 0.005 and P = 0.036, respectively). In contrast, KCl treatment exacerbated sGAG loss (P = 0.032) and MMP-1 protein expression (P = 0.010). NaCl treatment, however, did not alter sGAG loss or expression of OA-related proteins. Comparing LiCl and KCl treatment shows a potent reduction (P < 0.05) in catabolic and inflammatory mediators following LiCl treatment.

CONCLUSION

These results suggest that these ionic species elicit varying responses in TNF-α-stimulated explants. Cumulatively, these findings support additional studies of hyperosmolar ionic solutions for potential development of novel intraarticular injections targeting OA.

Modified Simiaowan prevents articular cartilage injury in experimental gouty arthritis by negative regulation of STAT3 pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Modified Simiaowan (MSW) is a traditional Chinese medicine formula that is composed of six herbs. It has been widely used in the treatment of gouty arthritis.

AIM OF THE STUDY

This study was designed to investigate the effect of MSW on gouty arthritis and explore the possible mechanisms.

MATERIAL AND METHODS

The rat gouty arthritis model was established by intra-articular injection of Monosodium Urate (MSU) crystal, and then treated with MSW for 5 days. The perimeter of the knee joints was measured in a time-dependent manner and serum samples were collected for the detection of TNF-α, IL-1β, and IL-6 protein levels by ELISA. The protein expressions of MMP-3, TIMP-3, STAT3, and p-STAT3 in cartilage tissues and C28/I2 cells were detected by Western blot, and the levels of proteoglycan in primary chondrocytes and cartilage tissues were determined by toluidine blue staining. In addition, AG490 and IL-6 were used in vitro to explore the function of IL-6/STAT3 pathway in the protective effect of MSU.

RESULTS

MSW reduced the joint swelling rate in gouty arthritis model and inhibited MSU induced up-regulation of IL-1β, TNF-α, and IL-6 protein levels in serum and synovial fluid. IL-1β induced an increase in p-STAT3 and MMP-3 protein expression in C28/I2 cells, as well as a decrease in TIMP-3. MSW serum inhibited the protein expression changes induced by IL-1β in vitro. Furthermore, inhibition of STAT3 signaling negated the effect of MSW serum on p-STAT3, MMP-3, and TIMP-3 protein levels in C28/I2 cells. MSW also increased the content of proteoglycan significantly both in vivo and in vitro.

CONCLUSION

Our data indicated that MSW protected rats from MSU-induced experimental gouty arthritis and IL-1β/IL-6/STAT3 pathway played an essential role in the protective effect of MSU against GA.

Inhibition of GPR17 with pranlukast protects against TNF-α-induced loss of type II collagen in ATDC5 cells

Osteoarthritis (OA) is a common joint disease affecting millions of elderly people worldwide. However, the mechanism of OA is complicated and remains poorly understood. Thus, a safe and effective therapeutic strategy has yet to be developed. G protein-coupled receptor 17 (GPR17) is an orphan receptor that is widely distributed in the central nervous system (CNS). GPR17 has become a target for the treatment of inflammation in brain diseases. In this study, we demonstrate that GPR17 is expressed in ATDC5 cells and is increased in response to TNF-α exposure. We also found that antagonism of GPR17 with pranlukast significantly inhibited oxidative stress by downregulating the intracellular level of reactive oxygen species (ROS) and increasing the activity of super oxide dismutase (SOD) against TNF-α. Interestingly, treatment with pranlukast prevented TNF-α-induced reduction of type II collagen. Additionally, knockdown of GPR17 with siRNA ameliorated TNF-α-induced loss of type II collagen, suggesting the importance of the role of GPR17 in mediating the impairment of type II collagen. Blockage of GPR17 with pranlukast suppressed the expression of matrix metalloproteinases 3 (MMP-3) and matrix metalloproteinases 13 (MMP-13), which contribute to the degradation of type II collagen. Pranlukast also prevented the activation of the JAK2/STAT1/IRF-1 signaling pathway, thereby suppressing the expression of pro-inflammatory cytokines and enzymes. Furthermore, pranlukast rescued TNF-α-induced reduced SOX-9 expression. Together, our data indicate that GPR17 might be a potential target for the treatment of OA.

Lithium as a candidate treatment for COVID-19: Promises and pitfalls

The pandemic of respiratory illness caused by a novel coronavirus (SARS-nCoV-2) is a global health crisis. Despite numerous preliminary results, there is as yet no treatment of proven efficacy for this condition. In this context, the pharmacological properties of lithium, better known as a treatment for mood disorders, merit closer examination. Lithium has shown in vitro efficacy at inhibiting the replication of coronaviruses responsible for gastrointestinal and respiratory diseases in animals. It has immunomodulatory properties that may be of additional benefit in moderating the host inflammatory response to the novel coronavirus (SARS-CoV-2). Furthermore, there is evidence that lithium may exert a protective action against upper respiratory infections and influenza-like illnesses in patients taking it for other indications. These promising reports must be balanced against the narrow therapeutic index and high risk of toxicity associated with lithium therapy, its documented interactions with several commonly used drugs, and the absence of evidence of its efficacy against coronaviruses responsible for human disease. Nevertheless, naturalistic studies of the risk of COVID-19 in patients already receiving lithium could provide indirect evidence of its efficacy, and understanding the putative antiviral and immune-regulatory mechanisms of lithium in models of SARS-CoV-2 infection may provide leads for the development of safer and more effective treatments with a specific action against COVID-19.

A lithium-containing biomaterial promotes chondrogenic differentiation of induced pluripotent stem cells with reducing hypertrophy

Background

Induced pluripotent stem cells (iPSCs) exhibit limitless pluripotent plasticity and proliferation capability to provide an abundant cell source for tissue regenerative medicine. Thus, inducing iPSCs toward a specific differentiation direction is an important scientific question. Traditionally, iPSCs have been induced to chondrocytes with the help of some small molecules within 21–36 days. To speed up the differentiation of iPSCs, we supposed to utilize bioactive ceramics to assist chondrogenic-induction process.

Methods

In this study, we applied ionic products (3.125~12.5 mg/mL) of the lithium-containing bioceramic (Li₂Ca₄Si₄O₁₃, L2C4S4) and individual Li⁺ (5.78~23.73 mg/L) in the direct chondrogenic differentiation of human iPSCs.

Results

Compared to pure chondrogenic medium and extracts of tricalcium phosphate (TCP), the extracts of L2C4S4 at a certain concentration range (3.125~12.5 mg/mL) significantly enhanced chondrogenic proteins Type II Collagen (COL II)/Aggrecan/ SRY-Box 9 (SOX9) synthesis and reduced hypertrophic protein type X collagen (COL X)/matrix metallopeptidase 13 (MMP13) production in iPSCs-derived chondrocytes within 14 days, suggesting that these newly generated chondrocytes exhibited favorable chondrocytes characteristics and maintained a low-hypertrophy state. Further studies demonstrated that the individual Li⁺ ions at the concentration range of 5.78~23.73 mg/L also accelerated the chondrogenic differentiation of iPSCs, indicating that Li⁺ ions played a pivotal role in chondrogenic differentiation process.

Conclusions

These findings indicated that lithium-containing bioceramic with bioactive specific ionic components may be used for a promising platform for inducing iPSCs toward chondrogenic differentiation and cartilage regeneration.

Lithium Chloride-Releasing 3D Printed Scaffold for Enhanced Cartilage Regeneration

Background

We synthetized a 3D printed poly-ɛ-caprolactone (PCL) scaffold with polydopamine (PDA) coating and lithium chloride (LiCl) deposition for cartilage tissue engineering and analyzed its effect on promoting rabbit bone marrow mesenchymal stem cells (rBMSC) chondrogenesis in vitro.

Material/Methods

PCL scaffolds were prepared by 3D printing with a well-designed CAD digital model, then modified by PDA coating to produce PCL-PDA scaffolds. Finally, LiCl was deposited on the PDA coating to produce PCL-PDA-Li scaffolds. The physicochemical properties, bioactivity, and biocompatibility of PCL-PDA-Li scaffolds were accessed by comparing them with PCL scaffolds and PCL-PDA scaffolds.

Results

3D PCL scaffolds exhibited excellent mechanical integrity as designed. PDA coating and LiCl deposition improved surface hydrophilicity without sacrificing mechanical strength. Li⁺ release was durable and ion concentration did not reach the cytotoxicity level. This in vitro study showed that, compared to PCL scaffolds, PCL-PDA and PCL-PDA-Li scaffolds significantly increased glycosaminoglycan (GAG) formation and chondrogenic marker gene expression, while PCL-PDA-Li scaffolds showed far higher rBMSC viability and chondrogenesis.

Conclusions

3D printed PCL-PDA-Li scaffolds promoted chondrogenesis in vitro and may provide a good method for lithium administration and be a potential candidate for cartilage tissue engineering.

Cortistatin binds to TNF-α receptors and protects against osteoarthritis

Background

Osteoarthritis (OA) is a common degenerative disease, and tumor necrosis factor (TNF-α) is known to play a critical role in OA. Cortistatin (CST) is a neuropeptide discovered over 20  years ago, which plays a vital role in inflammatory reactions. However, it is unknown whether CST is involved in cartilage degeneration and OA development.

Methods

The interaction between CST and TNF-α receptors was investigated through Coimmunoprecipitation and Biotin-based solid-phase binding assay. Western blot, Real-time PCR, ELISA, immunofluorescence staining, nitrite production assay and DMMB assay of GAG were performed for the primary chondrocyte experiments. Surgically induced and spontaneous OA models were established and western blot, flow cytometry, Real-time PCR, ELISA, immunohistochemistry and fluorescence in vivo imaging were performed for in vivo experiments.

Findings

CST competitively bound to TNFR1 as well as TNFR2. CST suppressed proinflammatory function of TNF-α. Both spontaneous and surgically induced OA models indicated that deficiency of CST led to an accelerated OA-like phenotype, while exogenous CST attenuated OA development in vivo. Additionally, TNFR1- and TNFR2-knockout mice were used for analysis and indicated that TNFRs might be involved in the protective role of CST in OA. CST inhibited activation of the NF-κB signaling pathway in OA.

Interpretation

This study provides new insight into the pathogenesis and therapeutic strategy of cartilage degenerative diseases, including OA.

Fund

The National Natural Science Foundation of China, the Natural Science Foundation of Shandong Province, Key Research and Development Projects of Shandong Province and the Cross-disciplinary Fund of Shandong University.

Heat challenge influences serum metabolites concentrations and liver lipid metabolism in Japanese quail (Coturnix japonica)

High temperature induces various metabolic disturbances in animals. However, no comprehensive information is currently available on the metabolic pathway affected by high environmental temperature. The present study examined metabolite content in the serum of heat challenged quails using metabolomic analysis. In the present study, female quails with normal laying rate at 20 weeks kept in standard condition (control group) or exposed to 34°C 4 hr per day (12:00 to 16:00 hr)(heat group) for 10 consecutive days. The metabolomic analysis identified 165 metabolites in the serum, and significant differences were observed in the serum for 7 metabolites between two groups. An analysis by MetaboAnalyst, a web-based metabolome data tool, indicate that high temperature affect ketone body metabolism, butyrate metabolism, arginine and proline metabolism. Furthermore, histological examination of liver indicates a heat challenge induced abnormal lipid metabolism. Triglyceride and cholesterol level in the liver increased, however cholesterol level decreased in the serum. Genes related to lipid metabolism significantly increased in the liver after heat challenge. The present study demonstrated that high temperature cause liver damage, thus lipid metabolic was affected. Protect liver under high temperature could be one solution for coping with high temperatures in summer.

Scoparone prevents IL-1β-induced inflammatory response in human osteoarthritis chondrocytes through the PI3K/Akt/NF-κB pathway

Osteoarthritis (OA) is a degenerative joint disease that is commonly accompanied by inflammation. Scoparone is a biologically active constituent isolated from Artemisia capillaris and possesses anti-inflammatory activity. However, the effect of scoparone on inflammatory response in OA has not been authenticated. The aim of this study was to evaluate the role of scoparone in OA in vitro. Our results showed that IL-1β treatment significantly inhibited the cell viability of chondrocytes, whereas the inhibition effect was attenuated by scoparone in a dose-dependent manner. IL-1β also efficiently induced the production of nitric oxide (NO), prostaglandin E2 (PGE2), MMP-3, MMP-13, ADAMTS-4 and ADAMTS-5 in chondrocytes. However, scoparone dose-dependently suppressed the induction. In addition, scoparone repressed IL-1β-induced the expression of iNOS and COX-2 in chondrocytes. Furthermore, the activation of the PI3K/Akt/NF-κB pathway induced by IL-1β was diminished by scoparone treatment. Taken together, these findings indicated that scoparone inhibited the expression of inflammatory mediators in IL-1β-induced chondrocytes via regulating the PI3K/Akt/NF-κB pathway. Thus, scoparone may be used as a new therapeutic agent for the treatment of OA.

Downregulation of HS6ST2 by miR-23b-3p enhances matrix degradation through p38 MAPK pathway in osteoarthritis

Osteoarthritis (OA) is the most common form of arthritis involving major structural changes of peripheral joints and local or systemic inflammation and in lack of therapeutic approaches because of complexity of underlying molecular basis. Our previous work showed that HS6ST2, an enzyme involved in the transfer of sulfate, is downregulated in cartilage tissues of OA patients compared with normal donors, but little is known about its regulatory mechanism. In this study, we demonstrated that the expression of HS6ST2 was lower in OA-damaged cartilage than smooth cartilage from the same patient. In chondrocytes, HS6ST2 could be targeted by miR-23b-3p, which was higher expressed in OA-damaged cartilage. Under TNF-α stimulation, the expression of HS6ST2 was found inversely correlated with the expression of miR-23b-3p. Downregulation of HS6ST2 regulated by overexpression of miR-23b-3p and siRNAs against HS6ST2 could enhance the protein level of MMP13 and aggravate the matrix degradation in chondrocytes. Increased expression of MMP13 depended on activity of p38 MAPK rather than total p38 MAPK level and was abrogated by HS6ST2 overexpression. Together, the results indicated that downregulated HS6ST2 targeted by miR-23b-3p promotes matrix degradation by activating p38 MAPK in chondrocytes and OA cartilage.

3D printing of a lithium-calcium-silicate crystal bioscaffold with dual bioactivities for osteochondral interface reconstruction

It is difficult to achieve self-healing outcoming for the osteochondral defects caused by degenerative diseases. The simultaneous regeneration of both cartilage and subchondral bone tissues is an effective therapeutic strategy for osteochondral defects. However, it is challenging to design a single type of bioscaffold with suitable ionic components and beneficial osteo/chondral-stimulation ability for regeneration of osteochondral defects. In this study, we successfully synthesized a pure-phase lithium calcium silicate (Li₂Ca₄Si₄O₁₃, L₂C₄S₄) bioceramic by a sol-gel method, and further prepared L₂C₄S₄ scaffolds by using a 3D-printing method. The compressive strength of L₂C₄S₄ scaffolds could be well controlled in the range of 15-40 MPa when pore size varied from 170 to 400 μm. L₂C₄S₄ scaffolds have been demonstrated to possess controlled biodegradability and good apatite-mineralization ability. At a certain concentration range, the ionic products from L₂C₄S₄ significantly stimulated the proliferation and maturation of chondrocytes, as well as promoted the osteogenic differentiation of rBMSCs. L₂C₄S₄ scaffolds simultaneously promoted the regeneration of both cartilage and subchondral bone as compared to pure β-TCP scaffolds in rabbit osteochondral defects. These findings suggest that 3D-printed L₂C₄S₄ scaffolds with such specific ionic combination, high mechanical strength and good degradability as well as dual bioactivities, represent a promising biomaterial for osteochondral interface reconstruction.

Ghrelin prevents articular cartilage matrix destruction in human chondrocytes

Osteoarthritis (OA) is the most common form of arthritis worldwide. Excessive production of pro-inflammatory cytokines such as interleukin-1β (IL-1β) plays a key role in the pathogenesis of OA. OA is generally characterized by degradation of extracellular matrixes such as type II collagen and aggrecans mediated by matrix metalloproteinases (MMPs) and a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS). Ghrelin is a secreted peptide hormone regulating appetite and the distribution and rate of use of energy. However, the physiological and pharmacological roles of Ghrelin on the pathological progression of OA haven't been reported before. In the current study, our results indicate that Ghrelin reduced IL-1β-induced expression of MMP-3, MMP-13, ADAMTS-4 and ADAMTS-5 in a concentration-dependent manner. Notably, Ghrelin ameliorated IL-1β-induced degradation of type II collagen and aggrecan. Mechanistically, Ghrelin is able to inhibit the expression of IRF-1 mediated by inactivating the JAK2/STAT3 pathway. However, Ghrelin didn't have any impact on IL-1β induced activation of p38. Taken together, our findings identify a novel function of Ghrelin on inhibiting the degradation of type II collagen and aggrecan.

Lithium-containing biomaterials inhibit osteoclastogenesis of macrophagesin vitroand osteolysisin vivo

Li-containing bioceramics were promising biomaterials for inhibiting osteoclastogenesis of macrophages and osteolysisin vivo, potentially using for treating osteoporosis.

Glycogen Synthase Kinase-3β Inhibition Links Mitochondrial Dysfunction, Extracellular Matrix Remodelling and Terminal Differentiation in Chondrocytes

Following inflammatory stimuli, GSK3 inhibition functions as a hub with pleiotropic effects leading to cartilage degradation. However, little is known about the effects triggered by its direct inhibition as well as the effects on mitochondrial pathology, that contributes to osteoarthritis pathogenesis. To this aim we assessed the molecular mechanisms triggered by GSK3β inactivating stimuli on 3-D (micromass) cultures of human articular chondrocytes. Stimuli were delivered either at micromass seeding (long term) or after maturation (short term) to explore “late” effects on terminal differentiation or “early” mitochondrial effects, respectively. GSK3β inhibition significantly enhanced mitochondrial oxidative stress and damage and endochondral ossification based on increased nuclear translocation of Runx-2 and β-catenin, calcium deposition, cell death and enhanced remodelling of the extracellular matrix as demonstrated by the increased collagenolytic activity of supernatants, despite unmodified (MMP-1) or even reduced (MMP-13) collagenase gene/protein expression. Molecular dissection of the underlying mechanisms showed that GSK3β inhibition achieved with pharmacological/silencing strategies impacted on the control of collagenolytic activity, via both decreased inhibition (reduced TIMP-3) and increased activation (increased MMP-10 and MMP-14). To conclude, the inhibition of GSK3β enhances terminal differentiation via concerted effects on ECM and therefore its activity represents a tool to keep articular cartilage homeostasis.

Lithium chloride enhances bone regeneration and implant osseointegration in osteoporotic conditions

Osteoporotic patients have a high risk of dental and orthopedic implant failure. Lithium chloride (LiCl) has been reported to enhance bone formation. However, the role of LiCl in the success rate of dental and orthopedic implants in osteoporotic conditions is still unknown. We investigated whether LiCl enhances implant osseointegration, implant fixation, and bone formation in osteoporotic conditions. Sprague-Dawley female rats (n = 18) were ovariectomized (OVX) to induce osteoporosis, and another nine rats underwent sham surgery. Three months after surgery, titanium implants were implanted in the tibia of the OVX and sham group rats. After implantation, the OVX rats were gavaged with 150 mg/kg/2 days of LiCl (OVX + LiCl group) or saline (OVX group), and sham group rats were gavaged with saline for 3 months. Implant osseointegration and bone formation were analyzed using histology, biomechanical testing, and micro computed tomography (micro-CT). More bone loss was observed in the OVX group compared to the control, and LiCl treatment enhanced bone formation and implant fixation in osteoporotic rats. In the OVX group, bone-implant contact (BIC) was decreased by 81.2 % compared to the sham group. Interestingly, the OVX + LiCl group showed 4.4-fold higher BIC compared to the OVX group. Micro-CT data of tibia from the OVX + LiCl group showed higher bone volume, trabecular thickness, trabecular number, and osseointegration compared to the OVX group. Maximum push-out force and implant-bone interface shear strength were 2.9-fold stronger in the OVX + LiCl group compared to the OVX group. In conclusion, LiCl enhanced implant osseointegration, implant fixation, and bone formation in osteoporotic conditions, suggesting LiCl as a promising therapeutic agent to prevent implant failure and bone loss in osteoporotic conditions.

Anemonin attenuates osteoarthritis progression through inhibiting the activation of IL-1β/NF-κB pathway

The osteoarthritis (OA) progression is now considered to be related to inflammation. Anemonin (ANE) is a small natural molecule extracted from various kinds of Chinese traditional herbs and has been shown to inhibiting inflammation response. In this study, we examined whether ANE could attenuate the progression of OA via suppression of IL‐1β/NF‐κB pathway activation. Destabilization of the medial meniscus (DMM) was performed in 10‐week‐old male C57BL/6J mice. ANE was then intra‐articularly injected into joint capsule for 8 and 12 weeks. Human articular chondrocytes and cartilage explants challenged with interleukin‐1β (IL‐1β) were treated with ANE. We found that ANE delayed articular cartilage degeneration in vitro and in vivo. In particular, proteoglycan loss and chondrocyte hypertrophy were significantly decreased in ANE ‐treated mice compared with vehicle‐treated mice. ANE decreased the expressions of matrix metalloproteinase‐13 (MMP13), A disintegrin and metalloproteinase with thrombospondin motifs 5 (ADAMTS5), collagen X (Col X) while increasing Aggrecan level in murine with DMM surgery. ANE treatment also attenuated proteoglycan loss in human cartilage explants treated with IL‐1β ex vivo. ANE is a potent protective molecule for OA; it delays OA progression by suppressing ECM loss and chondrocyte hypertrophy partially by suppressing IL‐1β/NF‐κB pathway activation.

Sol–gel derived lithium-releasing glass for cartilage regeneration

Wnt-signalling cascade is one of the crucial pathways involved in the development and homeostasis of cartilage. Influencing this pathway can potentially contribute to improved cartilage repair or regeneration. One key molecular regulator of the Wnt pathway is the glycogen synthase kinase-3 enzyme, the inhibition of which allows initiation of the signalling pathway. This study aims to utilise a binary SiO2–Li2O sol–gel derived glass for controlled delivery of lithium, a known glycogen synthase kinase-3 antagonist. The effect of the dissolution products of the glass on chondrogenic differentiation in an in vitro 3D pellet culture model is reported. Dissolution products that contained 5 mM lithium and 3.5 mM silicon were capable of inducing chondrogenic differentiation and hyaline cartilaginous matrix formation without the presence of growth factors such as TGF-β3. The results suggest that sol–gel derived glass has the potential to be used as a delivery vehicle for therapeutic lithium ions in cartilage regeneration applications.

Systemic inhibition of IL-6/Stat3 signalling protects against experimental osteoarthritis

Objective

To investigate the impact of systemic inhibition of interleukin 6 (IL-6) or signal transducer and activator of transcription (Stat3) in an experimental model of osteoarthritis (OA).

Methods

Expression of major catabolic and anabolic factors of cartilage was determined in IL-6-treated mouse chondrocytes and cartilage explants. The anti-IL-6-receptor neutralising antibody MR16-1 was used in the destabilisation of the medial meniscus (DMM) mouse model of OA. Stat3 blockade was investigated by the small molecule Stattic ex vivo and in the DMM model.

Results

In chondrocytes and cartilage explants, IL-6 treatment reduced proteoglycan content with increased production of matrix metalloproteinase (MMP-3 and MMP-13) and a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS-4 and ADAMTS-5). IL-6 induced Stat3 and extracellular signal-regulated kinase (ERK) 1/2 signalling but not p38, c-Jun N-terminal kinase or Akt. In the DMM model, Stat3 was activated in cartilage, but neither in the synovium nor in the subchondral bone. Systemic blockade of IL-6 by MR16-1 alleviated DMM-induced OA cartilage lesions, impaired the osteophyte formation and the extent of synovitis. In the same model, Stattic had similar beneficial effects on cartilage and osteophyte formation. Stattic, but not an ERK1/2 inhibitor, significantly counteracted the catabolic effects of IL-6 on cartilage explants and suppressed the IL-6-induced chondrocytes apoptosis.

Conclusion

IL-6 induces chondrocyte catabolism mainly via Stat3 signalling, a pathway activated in cartilage from joint subjected to DMM. Systemic blockade of IL-6 or STAT-3 can alleviate DMM-induced OA in mice.

Lithium-silicate sol-gel bioactive glass and the effect of lithium precursor on structure-property relationships

ABSTRACT

This work reports the synthesis of lithium-silicate glass, containing 10 mol% of Li 2 O by the sol-gel process, intended for the regeneration of cartilage. Lithium citrate and lithium nitrate were selected as lithium precursors. The effects of the lithium precursor on the sol-gel process, and the resulting glass structure, morphology, dissolution behaviour, chondrocyte viability and proliferation, were investigated. When lithium citrate was used, mesoporous glass containing lithium as a network modifier was obtained, whereas the use of lithium nitrate produced relatively dense glass-ceramic with the presence of lithium metasilicate, as shown by X-ray diffraction, 29 Si and 7 Li MAS NMR and nitrogen sorption data. Nitrate has a better affinity for lithium than citrate, leading to heterogeneous crystallisation from the mesopores, where lithium salts precipitated during drying. Citrate decomposed at a lower temperature, where the crystallisation of lithium-silicate crystal is not thermodynamically favourable. Upon decomposition of the citrate, a solid-state salt metathesis reaction between citrate and silanol occurred, followed by the diffusion of lithium within the structure of the glass. Both glass and glass-ceramic released silica and lithium ions in culture media, but release rate was lower for the glass-ceramic. Both samples did not affect chondrocyte viability and proliferation.

Association between psychiatric disorders and osteoarthritis: a nationwide longitudinal population-based study

Although the association between depressive disorders and osteoarthritis (OA) has been studied, the association of other psychiatric disorders with OA remains unclear. Here, we investigated whether psychiatric disorders are risk factors for OA.The data were obtained from the Longitudinal Health Insurance Database 2005 of Taiwan. We collected the ambulatory care claim records of patients who were diagnosed with psychiatric disorders according to the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes between January 1, 2004 and December 31, 2008. The prevalence and adjusted hazard ratios (HRs) of osteoarthritis among patients with psychiatric disorders and the control cohort were estimated.Of 74,393 patients with psychiatric disorders, 16,261 developed OA during the 7-year follow-up period. The crude HR for OA was 1.44 (95% confidence interval [CI], 1.39-1.49), which was higher than that of the control cohort. The adjusted HR for OA was 1.42 (95% CI, 1.39-1.42) among patients with psychiatric disorders during the 7-year follow-up period. Further analysis revealed that affective psychoses, neurotic illnesses or personality disorders, alcohol and drug dependence or abuse, and other mental disorders were risk factors for OA.This large-scale longitudinal population-based study revealed that affective psychoses, personality disorders, and alcohol and drug dependence or abuse are risk factors for OA.

A novel fibroblast growth factor receptor 1 inhibitor protects against cartilage degradation in a murine model of osteoarthritis

The attenuated degradation of articular cartilage by cartilage-specific deletion of fibroblast growth factor receptor 1 (FGFR1) in adult mice suggests that FGFR1 is a potential target for treating osteoarthritis (OA). The goal of the current study was to investigate the effect of a novel non-ATP-competitive FGFR1 inhibitor, G141, on the catabolic events in human articular chondrocytes and cartilage explants and on the progression of cartilage degradation in a murine model of OA. G141 was screened and identified via cell-free kinase-inhibition assay. In the in vitro study, G141 decreased the mRNA levels of catabolic markers ADAMTS-5 and MMP-13, the phosphorylation of Erk1/2, JNK and p38 MAPK, and the protein level of MMP-13 in human articular chondrocytes. In the ex vivo study, proteoglycan loss was markedly reduced in G141 treated human cartilage explants. For the in vivo study, intra-articular injection of G141 attenuated the surgical destabilization of the medial meniscus (DMM) induced cartilage destruction and chondrocyte hypertrophy and apoptosis in mice. Our data suggest that pharmacologically antagonize FGFR1 using G141 protects articular cartilage from osteoarthritic changes, and intra-articular injection of G141 is potentially an effective therapy to alleviate OA progression.

Lithium Chloride Dependent Glycogen Synthase Kinase 3 Inactivation Links Oxidative DNA Damage, Hypertrophy and Senescence in Human Articular Chondrocytes and Reproduces Chondrocyte Phenotype of Obese Osteoarthritis Patients

Introduction

Recent evidence suggests that GSK3 activity is chondroprotective in osteoarthritis (OA), but at the same time, its inactivation has been proposed as an anti-inflammatory therapeutic option. Here we evaluated the extent of GSK3β inactivation in vivo in OA knee cartilage and the molecular events downstream GSK3β inactivation in vitro to assess their contribution to cell senescence and hypertrophy.

Methods

In vivo level of phosphorylated GSK3β was analyzed in cartilage and oxidative damage was assessed by 8-oxo-deoxyguanosine staining. The in vitro effects of GSK3β inactivation (using either LiCl or SB216763) were evaluated on proliferating primary human chondrocytes by combined confocal microscopy analysis of Mitotracker staining and reactive oxygen species (ROS) production (2',7'-dichlorofluorescin diacetate staining). Downstream effects on DNA damage and senescence were investigated by western blot (γH2AX, GADD45β and p21), flow cytometric analysis of cell cycle and light scattering properties, quantitative assessment of senescence associated β galactosidase activity, and PAS staining.

Results

In vivo chondrocytes from obese OA patients showed higher levels of phosphorylated GSK3β, oxidative damage and expression of GADD45β and p21, in comparison with chondrocytes of nonobese OA patients. LiCl mediated GSK3β inactivation in vitro resulted in increased mitochondrial ROS production, responsible for reduced cell proliferation, S phase transient arrest, and increase in cell senescence, size and granularity. Collectively, western blot data supported the occurrence of a DNA damage response leading to cellular senescence with increase in γH2AX, GADD45β and p21. Moreover, LiCl boosted 8-oxo-dG staining, expression of IKKα and MMP-10.

Conclusions

In articular chondrocytes, GSK3β activity is required for the maintenance of proliferative potential and phenotype. Conversely, GSK3β inactivation, although preserving chondrocyte survival, results in functional impairment via induction of hypertrophy and senescence. Indeed, GSK3β inactivation is responsible for ROS production, triggering oxidative stress and DNA damage response.

Lithium chloride prevents interleukin-1β induced cartilage degradation and loss of mechanical properties

Osteoarthritis is a chronic degenerative disease that affects the articular cartilage. Recent studies have demonstrated that lithium chloride exhibits significant efficacy as a chondroprotective agent, blocking cartilage degradation in response to inflammatory cytokines. However, conflicting literature suggests lithium may affect the physicochemical properties of articular cartilage and thus long-term exposure may negatively affect the mechanical functionality of this tissue. This study aims to investigate the effect of lithium chloride on the biomechanical properties of healthy and interleukin-1β treated cartilage in vitro and examines the consequences of long-term exposure to lithium on cartilage health in vivo. Bovine cartilage explants were treated with lithium chloride for 12 days. Chondrocyte viability, matrix catabolism and the biomechanical properties of bovine cartilage explants were not significantly altered following treatment. Consistent with these findings, long term-exposure (9 months) to dietary lithium did not induce osteoarthritis in rats, as determined by histological staining. Moreover, lithium chloride did not induce the expression of catabolic enzymes in human articular chondrocytes. In an inflammatory model of cartilage destruction, lithium chloride blocked interleukin-1β signaling in the form of nitric oxide and prostaglandin E2 release and prevented matrix catabolism such that the loss of mechanical integrity observed with interleukin-1β alone was inhibited. This study provides further support for lithium chloride as a novel compound for the treatment of osteoarthritis.

Elevated expression of periostin in human osteoarthritic cartilage and its potential role in matrix degradation via matrix metalloproteinase-13

We investigated the role of periostin, an extracellular matrix protein, in the pathophysiology of osteoarthritis (OA). In OA, dysregulated gene expression and phenotypic changes in articular chondrocytes culminate in progressive loss of cartilage from the joint surface. The molecular mechanisms underlying this process are poorly understood. We examined periostin expression by immunohistochemical analysis of lesional and nonlesional cartilage from human and rodent OA knee cartilage. In addition, we used small interfering (si)RNA and adenovirus transduction of chondrocytes to knock down and up-regulate periostin levels, respectively, and analyzed its effect on matrix metalloproteinase (MMP)-13, a disintegrin and MMP with thrombospondin motifs (ADAMTS)-4, and type II collagen expression. We found high periostin levels in human and rodent OA cartilage. Periostin increased MMP-13 expression dose [1-10 µg/ml (EC50 0.5-1 μg/ml)] and time (24-72 h) dependently, significantly enhanced expression of ADAMTS4 mRNA, and promoted cartilage degeneration through collagen and proteoglycan degradation. Periostin induction of MMP-13 expression was inhibited by CCT031374 hydrobromide, an inhibitor of the canonical Wnt/β-catenin signaling pathway. In addition, siRNA-mediated knockdown of endogenous periostin blocked constitutive MMP-13 expression. These findings implicate periostin as a catabolic protein that promotes cartilage degeneration in OA by up-regulating MMP-13 through canonical Wnt signaling.

Emerging targets in osteoarthritis therapy

Osteoarthritis (OA) is a destructive joint disease in which the initiation may be attributed to direct injury and mechanical disruption of joint tissues, but the progressive changes are dependent on active cell-mediated processes that can be observed or inferred during the generally long time-course of the disease. Based on clinical observations and experimental studies, it is now recognized a that it is possible for individual patients to exhibit common sets of symptoms and structural abnormalities due to distinct pathophysiological pathways that act independently or in combination. Recent research that has focused on the underlying mechanisms involving biochemical cross talk among the cartilage, synovium, bone, and other joint tissues within a background of poorly characterized genetic factors will be addressed in this review.