Inhibitory effects of pentosan polysulfate sodium on MAP-kinase pathway and NF-κB nuclear translocation in canine chondrocytes in vitro

Research advances in the treatment of bone marrow edema syndrome

Bone marrow edema syndrome (BMES) is a relatively uncommon clinical condition. It has been poorly reported in the literature. Hence, doctors are not sufficiently aware of the disease and are prone to misdiagnosis and mistreatment, which can undoubtedly prolong the course of the disease, reduce the quality of life of patients and even affect their function. This paper reviews the literature and summarizes the treatment options for bone marrow edema syndrome, such as symptomatic treatment, extracorporeal shock waves therapy (ESWT), pulsed electromagnetic fields (PEFs), hyperbaric oxygen (HBO), vitamin D, iloprost, bisphosphonates, denosumab, and surgery, etc. This informs clinicians in treating bone marrow edema syndrome, hopefully improving patients' quality of life and shortening the duration of their disease.

Anti-inflammatory actions of Pentosan polysulfate sodium in a mouse model of influenza virus A/PR8/34-induced pulmonary inflammation

Introduction

There is an unmet medical need for effective anti-inflammatory agents for the treatment of acute and post-acute lung inflammation caused by respiratory viruses. The semi-synthetic polysaccharide, Pentosan polysulfate sodium (PPS), an inhibitor of NF-kB activation, was investigated for its systemic and local anti-inflammatory effects in a mouse model of influenza virus A/PR8/1934 (PR8 strain) mediated infection.

Methods

Immunocompetent C57BL/6J mice were infected intranasally with a sublethal dose of PR8 and treated subcutaneously with 3 or 6 mg/kg PPS or vehicle. Disease was monitored and tissues were collected at the acute (8 days post-infection; dpi) or post-acute (21 dpi) phase of disease to assess the effect of PPS on PR8-induced pathology.

Results

In the acute phase of PR8 infection, PPS treatment was associated with a reduction in weight loss and improvement in oxygen saturation when compared to vehicle-treated mice. Associated with these clinical improvements, PPS treatment showed a significant retention in the numbers of protective SiglecF+ resident alveolar macrophages, despite uneventful changes in pulmonary leukocyte infiltrates assessed by flow cytometry. PPS treatment in PR8- infected mice showed significant reductions systemically but not locally of the inflammatory molecules, IL-6, IFN-g, TNF-a, IL-12p70 and CCL2. In the post-acute phase of infection, PPS demonstrated a reduction in the pulmonary fibrotic biomarkers, sICAM-1 and complement factor C5b9.

Discussion

The systemic and local anti-inflammatory actions of PPS may regulate acute and post-acute pulmonary inflammation and tissue remodeling mediated by PR8 infection, which warrants further investigation.

Advances in the pharmaceutical treatment options for canine osteoarthritis

Canine osteoarthritis is a significant cause of pain in many dogs and can therefore compromise animal welfare. As the understanding of the biology and pain mechanisms underpinning osteoarthritis grows, so do the number of treatments available to manage it. Over the last decade, there have been a number of advances in the pharmaceutical treatment options available for dogs with osteoarthritis, as well as an increasing number of clinical trials investigating the efficacy of pre-existing treatments. This review aims to examine the current evidence behind pharmaceutical treatment options for canine osteoarthritis, including non-steroidal anti-inflammatory drugs, piprants, monoclonal antibodies, adjunctive analgesics, structure modifying osteoarthritis drugs and regenerative therapies.

Pentosan Polysulphate (PPS), a Semi-Synthetic Heparinoid DMOAD With Roles in Intervertebral Disc Repair Biology emulating The Stem Cell Instructive and Tissue Reparative Properties of Heparan Sulphate

This review highlights the attributes of pentosan polysulphate (PPS) in the promotion of intervertebral disc (IVD) repair processes. PPS has been classified as a disease modifying osteoarthritic drug (DMOAD) and many studies have demonstrated its positive attributes in the countering of degenerative changes occurring in cartilaginous tissues during the development of osteoarthritis (OA). Degenerative changes in the IVD also involve inflammatory cytokines, degradative proteases and cell signalling pathways similar to those operative in the development of OA in articular cartilage. PPS acts as a heparan sulphate (HS) mimetic to effect its beneficial effects in cartilage. The IVD contains small cell membrane HS-proteoglycans (HSPGs) such as syndecan, and glypican and a large multifunctional HS/chondroitin sulphate (CS) hybrid proteoglycan (HSPG2/perlecan) that have important matrix stabilising properties and sequester, control and present growth factors from the FGF, VEGF, PDGF and BMP families to cellular receptors to promote cell proliferation, differentiation and matrix synthesis. HSPG2 also has chondrogenic properties and stimulates the synthesis of extracellular matrix (ECM) components, expansion of cartilaginous rudiments and has roles in matrix stabilisation and repair. Perlecan is a perinuclear and nuclear proteoglycan in IVD cells with roles in chromatin organisation and control of transcription factor activity, immunolocalises to stem cell niches in cartilage, promotes escape of stem cells from quiescent recycling, differentiation and attainment of pluripotency and migratory properties. These participate in tissue development and morphogenesis, ECM remodelling and repair. PPS also localises in the nucleus of stromal stem cells, promotes development of chondroprogenitor cell lineages, ECM synthesis and repair and discal repair by resident disc cells. The availability of recombinant perlecan and PPS offer new opportunities in repair biology. These multifunctional agents offer welcome new developments in repair strategies for the IVD.

Pentosan polysulfate sodium prevents functional decline in chikungunya infected mice by modulating growth factor signalling and lymphocyte activation

Chikungunya virus (CHIKV) is an arthropod-borne virus that causes large outbreaks world-wide leaving millions of people with severe and debilitating arthritis. Interestingly, clinical presentation of CHIKV arthritides have many overlapping features with rheumatoid arthritis including cellular and cytokine pathways that lead to disease development and progression. Currently, there are no specific treatments or vaccines available to treat CHIKV infections therefore advocating the need for the development of novel therapeutic strategies to treat CHIKV rheumatic disease. Herein, we provide an in-depth analysis of an efficacious new treatment for CHIKV arthritis with a semi-synthetic sulphated polysaccharide, Pentosan Polysulfate Sodium (PPS). Mice treated with PPS showed significant functional improvement as measured by grip strength and a reduction in hind limb foot swelling. Histological analysis of the affected joint showed local inflammation was reduced as seen by a decreased number of infiltrating immune cells. Additionally, joint cartilage was protected as demonstrated by increased proteoglycan staining. Using a multiplex-immunoassay system, we also showed that at peak disease, PPS treatment led to a systemic reduction of the chemokines CXCL1, CCL2 (MCP-1), CCL7 (MCP-3) and CCL12 (MCP-5) which may be associated with the reduction in cellular infiltrates. Further characterisation of the local effect of PPS in its action to reduce joint and muscle inflammation was performed using NanoString™ technology. Results showed that PPS altered the local expression of key functional genes characterised for their involvement in growth factor signalling and lymphocyte activation. Overall, this study shows that PPS is a promising treatment for alphaviral arthritis by reducing inflammation and protecting joint integrity.

Molecular modification, structural characterization, and biological activity of xylans

The differences in the source and structure of xylans make them have various biological activities. However, due to their inherent structural limitations, the various biological activities of xylans are far lower than those of commercial drugs. Currently, several types of molecular modification methods have been developed to address these limitations, and many derivatives with specific biological activity have been obtained. Further research on structural characteristics, structure-activity relationship and mechanism of action is of great significance for the development of xylan derivatives. Therefore, the major molecular modification methods of xylans are introduced in this paper, and the primary structure and conformation characteristics of xylans and their derivatives are summarized. In addition, the biological activity and structure-activity relationship of the modified xylans are also discussed.

Pentosan polysulfate sodium for Ross River virus-induced arthralgia: a phase 2a, randomized, double-blind, placebo-controlled study

Background

Alphaviruses, such as Ross River (RRV) and chikungunya virus (CHIKV), cause significant global morbidity, with outbreaks of crippling joint inflammation and pain, leaving patients incapacitated for months to years. With no available vaccine or specific therapeutic for any alphaviral disease, and a growing economic and public health burden, there is a serious need for the development of specific therapies.

Methods

This study evaluated the safety and efficacy of pentosan polysulfate sodium (PPS) in subjects with RRV-induced arthralgia in a double-blind, placebo-controlled trial. Twenty subjects were randomized 2:1 to subcutaneous PPS (2 mg/kg) or placebo (sodium chloride 0.9%) twice weekly for 6 weeks. Safety evaluation included physical examination, concomitant medications, and laboratory findings. Efficacy assessments included change from baseline in joint function (hand grip strength and RAPID3) and quality of life (SF-36) at Days 15, 29, 39 and 81 after treatment initiation. Inflammatory and cartilage degradation biomarkers were exploratory endpoints.

Results

PPS was well tolerated, with a similar proportion of subjects reporting at least one treatment-emergent adverse event (TEAE) in the treatment and placebo groups. Injection site reactions were the most common TEAE and occurred more frequently in the PPS group. Dominant hand grip strength and SF-36 scores improved with PPS at all time points assessed, with hand grip strength improvement of 6.99 kg (p = 0.0189) higher than placebo at Day 15. PPS showed significant improvements versus placebo in adjusted mean relative change from baseline for RAPID3 Pain (p = 0.0197) and Total (p = 0.0101) scores at Day 15. At the conclusion of the study overall joint symptoms, assessed by RAPID3, showed near remission in 61.5% of PPS subjects versus 14.3% of placebo subjects. Additionally, PPS treatment improved COMP, CTX-II, CCL1, CXCL12, CXCL16 and CCL17 biomarker levels versus placebo.

Conclusions

Overall, the improvements in strength and joint symptoms warrant further evaluation of PPS as a specific treatment for RRV-induced and other forms of arthritis.

Trial registration

This trial is registered at the Australian New Zealand Clinical Trials Registry #ACTRN12617000893303.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04123-w.

Effects of pentosan polysulfate on cell proliferation, cell cycle progression and cyclin-dependent kinases expression in canine articular chondrocytes

Pentosan polysulfate (PPS) is a semi-synthetic sulfated polysaccharide compound which has been shown the benefits on therapeutic treatment for osteoarthritis (OA) and has been proposed as a disease modifying osteoarthritis drugs (DMOADs). This study investigated the effects of PPS on cell proliferation, particularly in cell cycle modulation and phenotype promotion of canine articular chondrocytes (AC). Canine AC were treated with PPS (0–80 µg/ml) for 24, 48 and 72 hr. The effect of PPS on cell viability, cell proliferation and cell cycle distribution were analyzed by MTT assay, DNA quantification and flow cytometry. Chondrocyte phenotype was analyzed by quantitative real-time PCR (qPCR) and glycosaminoglycan (GAG) quantification. PPS significantly reduced AC proliferation through cell cycle modulation particularly by maintaining a significantly higher proportion of chondrocytes in the G1 phase and a significantly lower proportion in the S phase of the cell cycle in a concentration- and time-dependent manner. While the proportion of chondrocytes in G1 phase corresponded with the significant downregulation of cyclin-dependent kinase (CDK) 1 and 4. Furthermore, the study confirms that PPS promotes a chondrogenic phenotype of AC through significant upregulation of collagen type II (Col2A1) mRNA and GAG synthesis. The effect of PPS on the inhibition of chondrocyte proliferation while promoting a chondrocyte phenotype could be beneficial in the early stages of OA treatment, which transient increase in proliferative activity of chondrocytes with subsequent phenotypic shift and less productive in an essential component of extracellular matrix (ECM) is observed.

Human osteocyte expression of Nerve Growth Factor: The effect of Pentosan Polysulphate Sodium (PPS) and implications for pain associated with knee osteoarthritis

Pentosan polysulphate sodium (PPS) is a promising therapeutic agent for blocking knee pain in individuals with knee osteoarthritis (KOA). The mode of action of PPS in this context is unknown. We hypothesised that the osteocyte, being the principal cell type in the sub-chondral bone, was capable of expressing the pain mediator Nerve Growth Factor (NGF), and that this may be altered in the presence of PPS. We tested the expression of NGF and the response to PPS in the presence or absence of the proinflammatory cytokine tumour necrosis factor-alpha (TNFα), in human osteocytes. For this we differentiated human primary osteoblasts grown from subchondral bone obtained at primary knee arthroplasty for KOA to an osteocyte-like stage over 28d. We also tested NGF expression in fresh osteocytes obtained by sequential digestion from KOA bone and by immunofluorescence in KOA bone sections. We demonstrate for the first time the production and secretion of NGF/proNGF by this cell type derived from patients with KOA, implicating osteocytes in the pain response in this pathological condition and possibly others. PPS inhibited TNFα-induced levels of proNGF secretion and TNFα induced NGF mRNA expression. Together, this provides evidence that PPS may act to suppress the release of NGF in the subchondral bone to ameliorate pain associated with knee osteoarthritis.

Improved clinical outcome measures of knee pain and function with concurrent resolution of subchondral Bone Marrow Edema Lesion and joint effusion in an osteoarthritic patient following Pentosan Polysulphate Sodium treatment: a case report

Background

At present, there are no registered products for the treatment of subchondral Bone Marrow Edema Lesion (BML) and associated knee pain. Patients who do not respond to current anti-inflammatory therapies are left with limited treatment options, and may resort to operative management with Total Knee Arthroplasty (TKA). We report the use of Pentosan Polysulphate Sodium (PPS) for the treatment of BMLs of the knee.

Case presentation

We report the case of a 70-year-old female with knee osteoarthritis presenting with a high level of knee pain, scoring 8 on the Numerical Rating Scale (NRS), and functional limitation demonstrating a poor Lysholm Knee Score of 37. MRI scans of the knee revealed subchondral BML in the medial femoral condyle and medial tibial plateau. The patient was administered a course of Pentosan Polysulphate Sodium (PPS) intramuscularly twice weekly, for 3 weeks. MRI scans 2 weeks post-treatment showed complete resolution of the bone marrow edema at the medial femoral condyle and medial tibial plateau with concomitant recovery from pain (NRS pain score of 0), and a 43% improvement of the Lysholm Knee Score. In addition, marked reduction in joint effusion was also demonstrated in the MRI scan post PPS therapy.

Conclusion

The MRI interpretations demonstrate improved clinical outcome measures ensuing therapeutic intervention with PPS, and warranting further investigation into the efficacy of PPS in the treatment of BML associated pain and dysfunction in the osteoarthritic population via randomized controlled trial, or equivalent rigorous methodological technique.

Effects of pentosan polysulfate and polysulfated glycosaminoglycan on chondrogenesis of canine bone marrow-derived mesenchymal stem cells in alginate and micromass culture

Mesenchymal stem cells (MSC) are a potential alternative source of differentiated chondrocytes for cartilage tissue regeneration and repair of osteoarthritic (OA) joints. We investigated the effects of pentosan polysulfate (PPS) and polysulfated glycosaminoglycan (PSGAG) on chondrogenesis of canine bone marrow-derived mesenchymal stem cells (cBMSC) in alginate and micromass cultures (MMC). Chondrogenic differentiation medium (CDM) was supplemented with PPS or PSGAG at concentrations of 0 (positive control; PC), 1, 3 and 5 µg/ml. 10% DMEM was used as negative control. Chondrocyte phenotype was analyzed by quantitative real-time PCR (qPCR) for alginate cultures and Alcian blue staining for proteoglycan (PG) synthesis for MMC. In alginate culture, PPS and PSGAG showed no significant effect on type II collagen, aggrecan and HIF-2α mRNA expression. PPS had no significant effect on type I collagen whereas PSGAG significantly upregulated (P<0.05) it at all concentrations relative to other treatments. PPS demonstrated a dose-dependent inhibitory effect on type X collagen mRNA with significant inhibition observed at 5 µg/ml compared to the NC. PSGAG showed an inverse effect on type X collagen with 1 µg/ml significantly inhibiting its expression while increase in the concentration correspondingly increased type X collagen expression. In MMC, PPS significantly enhanced chondrogenesis and PG deposition whereas PSGAG inhibited chondrogenesis and promoted a fibrocartilage-like phenotype with reduced PG deposition. While PPS enhances chondrogenesis of cBMSC in MMC, the response of MSC to chondroinductive factors is culture system-dependent and varies significantly between alginate and MMC.

Pentosan polysulfate inhibits IL-1β-induced iNOS, c-Jun and HIF-1α upregulation in canine articular chondrocytes

Osteoarthritic (OA) chondrocytes are shown to express inducible nitric oxide synthase (iNOS) which produces high concentrations of nitric oxide (NO), particularly when stimulated with proinflammatory cytokines. NO is involved in OA cartilage degradation. On the other hand, c-Jun N-terminal Kinase (JNK) pathway mediates the activation and transcription of c-Jun, which is required for interleukin-1 (IL-1)-induction of matrix metalloproteinases-13 (MMP-13) in OA pathogenesis. Therefore, the selective inhibition of iNOS and c-Jun is a promising target for treatment and prevention of OA. The purpose of the study was to investigate the inhibitory effects of pentosan polysulfate (PPS) on IL-1β-induced iNOS, c-Jun and HIF-α isoforms upregulation in canine articular chondrocytes (CACs). Primary (P0) chondrocytes were isolated and cultured from femoral head cartilages of three (3) dogs. First passage (P1) chondrocytes were preincubated with 0, 1, 5, 15 and 40 μg/mL of PPS for 4 hr before treatment with 10 ng/mL rhIL-1β for a further 8 hr. In addition, we evaluated the effects of single and multiple cytokine with or without LPS on iNOS protein induction. PPS significantly inhibited (P < 0.05) IL-1β-induced iNOS, c-Jun and HIF-1α mRNA upregulation in a dose-dependent pattern. iNOS mRNA was significantly inhibited at 15 and 40 μg/mL whereas c-Jun and HIF-1α were significantly downregulated at 5, 15 and 40 μg/mL of PPS compared to chondrocytes treated with only rhIL-1β. Intriguingly, CACs were recalcitrant to single IL-1β, TNF-α or LPS-induction of iNOS protein including to a combination of IL-1β+TNF-α, IL-1β+LPS except to TNF-α+LPS and IL-1β+TNF-α+LPS suggestive of a protective mechanism from iNOS detrimental effects on perpetuating OA. IL-1β+TNF-α+LPS-induced iNOS protein expression was significantly abrogated by PPS. We demonstrate for the first time that PPS is a novel inhibitor of IL-1β-induced iNOS, c-Jun, and HIF-1α mRNA upregulation and iNOS protein induction which may be beneficial for prevention and treatment OA.

Systems Based Study of the Therapeutic Potential of Small Charged Molecules for the Inhibition of IL-1 Mediated Cartilage Degradation

Inflammatory cytokines are key drivers of cartilage degradation in post-traumatic osteoarthritis. Cartilage degradation mediated by these inflammatory cytokines has been extensively investigated using in vitro experimental systems. Based on one such study, we have developed a computational model to quantitatively assess the impact of charged small molecules intended to inhibit IL-1 mediated cartilage degradation. We primarily focus on the simplest possible computational model of small molecular interaction with the IL-1 system-direct binding of the small molecule to the active site on the IL-1 molecule itself. We first use the model to explore the uptake and release kinetics of the small molecule inhibitor by cartilage tissue. Our results show that negatively charged small molecules are excluded from the negatively charged cartilage tissue and have uptake kinetics in the order of hours. In contrast, the positively charged small molecules are drawn into the cartilage with uptake and release timescales ranging from hours to days. Using our calibrated computational model, we subsequently explore the effect of small molecule charge and binding constant on the rate of cartilage degradation. The results from this analysis indicate that the small molecules are most effective in inhibiting cartilage degradation if they are either positively charged and/or bind strongly to IL-1α, or both. Furthermore, our results showed that the cartilage structural homeostasis can be restored by the small molecule if administered within six days following initial tissue exposure to IL-1α. We finally extended the scope of the computational model by simulating the competitive inhibition of cartilage degradation by the small molecule. Results from this model show that small molecules are more efficient in inhibiting cartilage degradation by binding directly to IL-1α rather than binding to IL-1α receptors. The results from this study can be used as a template for the design and development of more pharmacologically effective osteoarthritis drugs, and to investigate possible therapeutic options.

Mori folium inhibits interleukin-1β-induced expression of matrix metalloproteinases and inflammatory mediators by suppressing the activation of NF-κB and p38 MAPK in SW1353 human chondrocytes

The pro-inflammatory cytokine interleukin-1β (IL-1β) is known to play a crucial role in the pathogenesis of osteoarthritis (OA) by stimulating several mediators that contribute to cartilage degradation. Mori folium, the leaves of Morus alba L., has long been used in traditional medicine to treat diabetes, protect the liver, and lower blood pressure; however, the role of Mori folium in OA is not yet fully understood. Therefore, in the present study, we investigated whether Mori folium water extract (MF) inhibited the catabolic effects of IL-1β in vitro, and also whether it inhibited the matrix metalloproteinases (MMPs), inducible nitric oxide (NO) synthase (iNOS) and cyclooxygenase-2 (COX-2) through the attenuation of nuclear factor-κB (NF-κB) and mitogen activated protein kinase (MAPK) pathways in SW1353 human chondrocytes. MMP proteins in culture medium were determined using a cytokine‑specific enzyme-linked immunosorbent assay (ELISA). The production of NO and prostaglandin E2 (PGE2) were evaluated using Griess reagent and ELISA. Subsequently, the mRNA and protein levels of MMPs, iNOS, COX-2, NF-κB and MAPKs were examined by RT-qPCR and/or western blot analysis. The results indicate that MF significantly reduced the IL-1β‑induced release of MMP-1 and -13 in SW1353 cells, which was associated with the inhibition of MMP-1 and -13 mRNA and protein expression in a concentration‑dependent manner at concentrations with no cytotoxicity. MF also attenuated the IL-1β-induced production of NO and PGE2, and reduced iNOS and COX-2 expression. Furthermore, we noted that MF markedly suppressed the IL-1β‑induced nuclear translocation of NF-κB, which correlated with the inhibitory effects of MF on inhibitor-κB (IκB) degradation, and the phosphorylation of p38 MAPK was selectively restored by MF upon IL-1β stimulation. These results indicate that MF inhibited the production and expression of MMP-1 and -13 and inflammatory mediators, at least in part, through suppressing the activation of either NF-κB or p38 MAPK in IL-1β-treated SW1353 chondrocytes. Therefore, the novel findings of the present study suggest that MF is a potential therapeutic choice for chondroprotection against the collagen matrix breakdown in the cartilage of diseased tissues, such as those found in patients with arthritic disorders.

Taraxasterol inhibits IL-1β-induced inflammatory response in human osteoarthritic chondrocytes

Osteoarthritis (OA), a chronic degenerative joint disease, is a leading cause of disability among elderly patients. Taraxasterol, a pentacyclic-triterpene isolated from Taraxacum officinale, has been shown to have anti-inflammatory effects. However, the protective effect of taraxasterol on OA remains unclear. In order to provide a scientific basis for the applicability of taraxasterol in OA, the anti-inflammatory effects of taraxasterol on IL-1β-stimulated osteoarthritic chondrocytes were investigated. Chondrocytes were pretreated with taraxasterol 1h before IL-1β treatment. The productions of MMP-1, MMP3, MMP13, PGE2 and NO were measured by ELISA and Griess reaction. The expression of COX-2, iNOS, and NF-κB was detected by western blot analysis. Our results demonstrated that taraxasterol dose-dependently suppressed MMP-1, MMP3, MMP13, PGE2 and NO production induced by IL-1β. The expression of COX-2 and iNOS was also inhibited by taraxasterol. Western blot analysis showed that taraxasterol suppressed IL-1β-induced NF-κB activation in a dose-dependent manner. Taken together, we found that taraxasterol protected human chondrocytes by inhibiting MMPs, NO and PGE2 production. Taraxasterol may be a useful agent for prevention and treatment of OA.

Mesenchymal progenitor cells combined with pentosan polysulfate mediating disc regeneration at the time of microdiscectomy: a preliminary study in an ovine model

OBJECT

Following microdiscectomy, discs generally fail to undergo spontaneous regeneration and patients may experience chronic low-back pain and recurrent disc prolapse. In published studies, formulations of mesenchymal progenitor cells combined with pentosan polysulfate (MPCs+PPS) have been shown to regenerate disc tissue in animal models, suggesting that this approach may provide a useful adjunct to microdiscectomy. The goal of this preclinical laboratory study was to determine if the transplantation of MPCs+PPS, embedded in a gelatin/fibrin scaffold (SCAF), and transplanted into a defect created by microdiscectomy, could promote disc regeneration.

METHODS

A standardized microdiscectomy procedure was performed in 18 ovine lumbar discs. The subsequent disc defects were randomized to receive either no treatment (NIL), SCAF only, or the MPC+PPS formulation added to SCAF (MPCs+PPS+SCAF). Necropsies were undertaken 6 months postoperatively and the spines analyzed radiologically (radiography and MRI), biochemically, and histologically.

RESULTS

No adverse events occurred throughout the duration of the study. The MPC+PPS+SCAF group had significantly less reduction in disc height compared with SCAF-only and NIL groups (p < 0.05 and p < 0.01, respectively). Magnetic resonance imaging Pfirrmann scores in the MPC+PPS+SCAF group were significantly lower than those in the SCAF group (p = 0.0213). The chaotropic solvent extractability of proteoglycans from the nucleus pulposus of MPC+PPS+SCAF-treated discs was significantly higher than that from the SCAF-only discs (p = 0.0312), and using gel exclusion chromatography, extracts from MPC+PPS+SCAF-treated discs also contained a higher percentage of proteoglycan aggregates than the extracts from both other groups. Analysis of the histological sections showed that 66% (p > 0.05) of the MPC+PPS+SCAF-treated discs exhibited less degeneration than the NIL or SCAF discs.

CONCLUSIONS

These findings demonstrate the capacity of MPCs in combination with PPS, when embedded in a gelatin sponge and sealed with fibrin glue in a microdiscectomy defect, to restore disc height, disc morphology, and nucleus pulposus proteoglycan content.

The regulation of the expression of ABCG2 gene through mitogen-activated protein kinase pathways in canine lymphoid tumor cell lines

Treatments for canine lymphoma often fail, because tumor cells acquire multidrug resistance (MDR). MDR can develop through several mechanisms, among which the overexpression of drug transporters in tumor cells is a well-studied mechanism. ATP-binding cassette sub-family G member 2 (ABCG2) belongs to the ABC-transporters, that are representative drug efflux pumps associated with MDR in human tumor cells. However, the regulation of ABCG2 gene expression in canine tumors is not well understood. The purpose of the present study was to reveal the regulatory mechanism of ABCG2 gene expression in 4 canine lymphoid tumor cell lines, GL-1, CLBL-1, UL-1 and Ema. Treatment with phorbol 12-myristate 13-acetate (PMA), the protein kinase C (PKC) activator, stimulated MAPK/ERK pathway in GL-1, UL-1 and Ema cells and JNK pathway in UL-1 and Ema cells. When GL-1 and UL-1 cells were treated with PMA and the MAPK/ERK kinase inhibitor U0126, ABCG2 gene expression levels were elevated above those in untreated cells. Similarly, ABCG2 gene expression increased above control levels in UL-1 and Ema cells treated with PMA and the JNK inhibitor SP600125. However, ABCG2 gene expression was unaffected by U0126 exposure in CLBL-1 cells, in which activation of MAPK/ERK pathway was observed in non-treated cells. These results suggested that MAPK/ERK and JNK pathways downregulate ABCG2 gene expression, which is upregulated by unidentified but possibly PKC-dependent pathways, in several types of canine lymphoid tumor cells.