The pathobiology of osteoarthritis and the rationale for the use of pentosan polysulfate for its treatment

Efficacy and safety of pentosan polysulfate sodium in people with symptomatic knee osteoarthritis and dyslipidaemia: protocol of the MaRVeL trial

INTRODUCTION

Knee osteoarthritis (OA) is the most prevalent arthritis type and a leading cause of chronic mobility disability. While pain medications provide only symptomatic pain relief; growing evidence suggests pentosan polysulfate sodium (PPS) is chondroprotective and could have anti-inflammatory effects in knee OA. This study aims to explore the efficacy and safety of oral PPS in symptomatic knee OA with dyslipidaemia.

METHODS AND ANALYSIS

MaRVeL is a phase II, single-centre, parallel, superiority trial which will be conducted at Royal North Shore Hospital, Sydney, Australia. 92 participants (46 per arm) aged 40 and over with painful knee OA and mild to moderate structural change on X-ray (Kellgren and Lawrence grade 2 or 3) will be recruited from the community and randomly allocated to receive two cycles of either oral PPS or placebo for 5 weeks starting at baseline and week 11. Primary outcome will be the 16-week change in overall average knee pain severity measured using an 11-point Numeric Rating Scale. Main secondary outcomes include change in knee pain, patient global assessment, physical function, quality of life and other structural changes. A biostatistician blinded to allocation groups will perform the statistical analysis according to the intention-to-treat principle.

ETHICS AND DISSEMINATION

The protocol has been approved by the NSLHD Human Research Ethics Committee (HREC) (2021/ETH00315). All participants will provide written informed consent online. Study results will be disseminated through conferences, social media and academic publications.

TRIAL REGISTRATION NUMBERS

Australian New Zealand Clinical Trial Registry (ACTRN12621000654853); U1111-1265-3750.

Mechanical osteoarthritis of the hip in a one medicine concept: a narrative review

Human and veterinary medicine have historically presented many medical areas of potential synergy and convergence. Mechanical osteoarthritis (MOA) is characterized by a gradual complex imbalance between cartilage production, loss, and derangement. Any joint instability that results in an abnormal overload of the joint surface can trigger MOA. As MOA has a prevailing mechanical aetiology, treatment effectiveness can only be accomplished if altered joint mechanics and mechanosensitive pathways are normalized and restored. Otherwise, the inflammatory cascade of osteoarthritis will be initiated, and the changes may become irreversible. The management of the disease using non-steroidal anti-inflammatory drugs, analgesics, physical therapy, diet changes, or nutraceuticals is conservative and less effective. MOA is a determinant factor for the development of hip dysplasia in both humans and dogs. Hip dysplasia is a hereditary disease with a high incidence and, therefore, of great clinical importance due to the associated discomfort and significant functional limitations. Furthermore, on account of analogous human and canine hip dysplasia disease and under the One Medicine concept, unifying veterinary and human research could improve the well-being and health of both species, increasing the acknowledgement of shared diseases. Great success has been accomplished in humans regarding preventive conservative management of hip dysplasia and following One Medicine concept, similar measures would benefit dogs. Moreover, animal models have long been used to better understand the different diseases' mechanisms. Current research in animal models was addressed and the role of rabbit models in pathophysiologic studies and of the dog as a spontaneous animal model were highlighted, denoting the inexistence of rabbit functional models to investigate therapeutic approaches in hip MOA.

The effect of pentosan polysulfate sodium for improving dyslipidaemia and knee pain in people with knee osteoarthritis: A pilot study

Objective

To evaluate the efficacy and safety of pentosan polysulfate sodium (PPS, Elmiron®) for dyslipidaemia and knee osteoarthritis (OA) related symptoms.

Method

This was a single-arm, open-label, prospective, non-randomised pilot study. People with painful knee OA and a history of primary hypercholesterolemia were included. PPS was taken orally in a dosage of 10 ​mg/kg once every 4 days for 5 weeks for two cycles. There was 5 weeks of no medication between the cycles. The main outcomes included the change in lipidemia levels, the change in knee OA-related symptoms assessed by pain numerical rating scale (NRS) and Knee Osteoarthritis Outcome Score (KOOS), and knee MRI semi-quantitative score. The changes were analysed using paired t-tests.

Results

38 participants were included, with a mean age of 62.2 years. We found a statistically significant decrease in total cholesterol (from 6.23 ​± ​0.74 to 5.95 ​± ​0.77 ​mmol/L; P ​= ​0.01) and low-density lipoprotein (from 4.03 ​± ​0.61 to 3.82 ​± ​0.61 ​mmol/L; P ​= ​0.009) from baseline to week 16. Knee pain NRS was significantly reduced at weeks 6, 16 and 26 from 6.39 ​± ​1.33 to 4.18 ​± ​1.99, 3.63 ​± ​2.28 and 4.38 ​± ​2.55, respectively (P ​< ​0.001). However, there was no significant difference in terms of the primary outcome of triglyceride levels before and after treatment. The most common AEs were positive faecal occult blood tests, followed by headache and diarrhoea.

Conclusion

The findings suggest that PPS has promising effects on improving dyslipidaemia and symptomatic pain relief in people with knee OA.

HAM/TSP Pathogenesis: The Transmigration Activity of HTLV-1-Infected T Cells into Tissues

Slowly progressive spastic paraparesis with bladder dysfunction, the main clinical feature of human T-cell leukemia virus-1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP), is induced by chronic inflammation in the spinal cord, mainly the lower thoracic cord. A long-standing bystander mechanism, such as the destruction of surrounding tissues by inflammatory cytokines, etc., induced under the interaction between infiltrated HTLV-1-infected CD4⁺ T cells and HTLV-1-specific CD8⁺ cytotoxic T cells, has been considered implicated for the induction of chronic inflammation. As this bystander mechanism is triggered conceivably by the transmigration of HTLV-1-infected CD4⁺ T cells to the spinal cord, heightened transmigrating activity of HTLV-1-infected CD4⁺ T cells to the spinal cord might play a crucial role as the first responder in the development of HAM/TSP. This review evaluated the functions of HTLV-1-infected CD4⁺ T cells in HAM/TSP patients as the prerequisite for the acquisition of the activity such as adhesion molecule expression changes, small GTPases activation, and expression of mediators involved in basement membrane disruption. The findings suggest that HTLV-1-infected CD4⁺ T cells in HAM/TSP patients have enough potential to facilitate transmigration into the tissues. Future HAM/TSP research should clarify the molecular mechanisms leading to the establishment of HTLV-1-infected CD4⁺ T cells as the first responder in HAM/TSP patients. In addition, a regimen with an inhibitory activity against the transmigration of HTLV-1-infected CD4⁺ T cells into the spinal cord might be recommended as one of the therapeutic strategies against HAM/TSP patients.

Pentosan Polysulfate Affords Pleotropic Protection to Multiple Cells and Tissues

Pentosan polysulfate (PPS), a small semi-synthetic highly sulfated heparan sulfate (HS)-like molecule, shares many of the interactive properties of HS. The aim of this review was to outline the potential of PPS as an interventional therapeutic protective agent in physiological processes affecting pathological tissues. PPS is a multifunctional molecule with diverse therapeutic actions against many disease processes. PPS has been used for decades in the treatment of interstitial cystitis and painful bowel disease, it has tissue-protective properties as a protease inhibitor in cartilage, tendon and IVD, and it has been used as a cell-directive component in bioscaffolds in tissue engineering applications. PPS regulates complement activation, coagulation, fibrinolysis and thrombocytopenia, and it promotes the synthesis of hyaluronan. Nerve growth factor production in osteocytes is inhibited by PPS, reducing bone pain in osteoarthritis and rheumatoid arthritis (OA/RA). PPS also removes fatty compounds from lipid-engorged subchondral blood vessels in OA/RA cartilage, reducing joint pain. PPS regulates cytokine and inflammatory mediator production and is also an anti-tumor agent that promotes the proliferation and differentiation of mesenchymal stem cells and the development of progenitor cell lineages that have proven to be useful in strategies designed to effect repair of the degenerate intervertebral disc (IVD) and OA cartilage. PPS stimulates proteoglycan synthesis by chondrocytes in the presence or absence of interleukin (IL)-1, and stimulates hyaluronan production by synoviocytes. PPS is thus a multifunctional tissue-protective molecule of potential therapeutic application for a diverse range of disease processes.

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.

Transient Postoperative Hemorrhage from Elbow Arthroscopy Portals following Intra-Articular Pentosan Polysulfate Sodium Injection

Four adult, client owned dogs with diagnosed bilateral elbow dysplasia undergoing elbow arthroscopy for removal of fragmented medial coronoid process were identified via a retrospective database search, who also received intra-articular administration of pentosan polysulfate sodium (PPS) (Cartrophen Vet, Biopharm Australia Pty Ltd., Bondi Junction, New South Wales). Dogs had postoperative administration of 5 ml PPS injected into each elbow joint following elbow arthroscopy. Within 1-3 hours of administration, each dog experienced hemorrhage from arthroscopy incisions that was determined to be independent of surgical trauma given lack of hemorrhage intraoperatively. Pressure bandages were placed, and the hemorrhage and elevated coagulation parameters resolved 12-18 hours following intra-articular injection. No further intervention was required, and the dogs were discharged 20-26 hours postoperatively. The purpose of this case series is to describe 4 dogs who experienced transient and focal hemorrhage following off-label intra-articular administration of pentosan polysulfate sodium (PPS). While this case series is limited due to small number of cases, results following bilateral, intra-articular injection of PPS support a transient systemic coagulopathy. Though this report represents administration of PSS via a route and at doses beyond that recommended on the label, results suggest that administration of PSS in the manner described in this report should be avoided.

Xylan Prebiotics and the Gut Microbiome Promote Health and Wellbeing: Potential Novel Roles for Pentosan Polysulfate

This narrative review highlights the complexities of the gut microbiome and health-promoting properties of prebiotic xylans metabolized by the gut microbiome. In animal husbandry, prebiotic xylans aid in the maintenance of a healthy gut microbiome. This prevents the colonization of the gut by pathogenic organisms obviating the need for dietary antibiotic supplementation, a practice which has been used to maintain animal productivity but which has led to the emergence of antibiotic resistant bacteria that are passed up the food chain to humans. Seaweed xylan-based animal foodstuffs have been developed to eliminate ruminant green-house gas emissions by gut methanogens in ruminant animals, contributing to atmospheric pollution. Biotransformation of pentosan polysulfate by the gut microbiome converts this semi-synthetic sulfated disease-modifying anti-osteoarthritic heparinoid drug to a prebiotic metabolite that promotes gut health, further extending the therapeutic profile and utility of this therapeutic molecule. Xylans are prominent dietary cereal components of the human diet which travel through the gastrointestinal tract as non-digested dietary fibre since the human genome does not contain xylanolytic enzymes. The gut microbiota however digest xylans as a food source. Xylo-oligosaccharides generated in this digestive process have prebiotic health-promoting properties. Engineered commensal probiotic bacteria also have been developed which have been engineered to produce growth factors and other bioactive factors. A xylan protein induction system controls the secretion of these compounds by the commensal bacteria which can promote gut health or, if these prebiotic compounds are transported by the vagal nervous system, may also regulate the health of linked organ systems via the gut–brain, gut–lung and gut–stomach axes. Dietary xylans are thus emerging therapeutic compounds warranting further study in novel disease prevention protocols.

HIF-1α in Osteoarthritis: From Pathogenesis to Therapeutic Implications

Osteoarthritis is a common age-related joint degenerative disease. Pain, swelling, brief morning stiffness, and functional limitations are its main characteristics. There are still no well-established strategies to cure osteoarthritis. Therefore, better clarification of mechanisms associated with the onset and progression of osteoarthritis is critical to provide a theoretical basis for the establishment of novel preventive and therapeutic strategies. Chondrocytes exist in a hypoxic environment, and HIF-1α plays a vital role in regulating hypoxic response. HIF-1α responds to cellular oxygenation decreases in tissue regulating survival and growth arrest of chondrocytes. The activation of HIF-1α could regulate autophagy and apoptosis of chondrocytes, decrease inflammatory cytokine synthesis, and regulate the chondrocyte extracellular matrix environment. Moreover, it could maintain the chondrogenic phenotype that regulates glycolysis and the mitochondrial function of osteoarthritis, resulting in a denser collagen matrix that delays cartilage degradation. Thus, HIF-1α is likely to be a crucial therapeutic target for osteoarthritis via regulating chondrocyte inflammation and metabolism. In this review, we summarize the mechanism of hypoxia in the pathogenic mechanisms of osteoarthritis, and focus on a series of therapeutic treatments targeting HIF-1α for osteoarthritis. Further clarification of the regulatory mechanisms of HIF-1α in osteoarthritis may provide more useful clues to developing novel osteoarthritis treatment strategies.

Proposed Canadian Consensus Guidelines on Osteoarthritis Treatment Based on OA-COAST Stages 1–4

The Canadian consensus guidelines on OA treatment were created from a diverse group of experts, with a strong clinical and/or academic background in treating OA in dogs. The document is a summary of the treatment recommendations made by the group, with treatments being divided into either a core or secondary recommendation. Each treatment or modality is then summarized in the context of available research based support and clinical experience, as the treatment of OA continues to be a multimodal and commonly a multidisciplinary as well as individualized approach. The guidelines aim to help clinicians by providing clear and clinically relevant information about treatment options based on COAST defined OA stages 1–4.

Pentosan polysulfate regulates hepcidin 1-facilitated formation and function of osteoclast derived from canine bone marrow

Hepcidin which is the crucial regulator of iron homeostasis, produced in the liver in response to anemia, hypoxia, or inflammation. Recent studies have suggested that hepcidin and iron metabolism are involved in osteoporosis by inhibiting osteoblast function and promoting osteoclastogenesis. Pentosan polysulfate (PPS) is a heparin analogue and promising novel therapeutic for osteoarthritis (OA). This study was undertaken to determine whether PPS inhibits hepcidin-facilitated osteoclast (OC) differentiation and iron overload. Canine (n = 3) bone marrow mononuclear cells were differentiated to OC by macrophage colony-stimulating factor and receptor-activator of nuclear factor kappaB ligand with the treatment of hepcidin1 (200, 400, 800, 1200 nmol/L) and PPS (1, 5, 10, 20, 40 μg/mL). Differentiation and function of OC were accessed using tartrate-resistant acid phosphate staining and bone resorption assay while monitoring ferroportin1 (FPN1) and iron concentration by immunocytochemistry. Gene expression of OC for cathepsin K (CTK), matrix metallopeptidase-9, nuclear factor of activated-T-cells cytoplasmic 1 and FPN1 was examined. Hepcidin1 showed significant enhancement of OC number at 800 nmol/L (p<0.01). PPS impeded hepcidin-facilitated OC at 1, 5 and 10 μg/mL and reduction of resorption pits at 5 and 10 μg/mL (p< 0.01). All OC specific genes were downregulated with PPS, specifically in significant manner with CTK at higher concentrations. However, heparin induced FPN1 internalization and degradation was inhibited at higher concentrations of PPS while restoring iron-releasing capability of OC. We demonstrate for the first time that PPS is a novel-inhibitor of hepcidin-facilitated OC formation/function which might be beneficial for treatment of OA and osteoporosis.

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.

Acute and severe haemorrhage following pentosan polysulfate injection in a Cornish Rex

Case summary

A 14-year-old male castrated Cornish Rex cat was referred for lethargy progressing rapidly to collapse in the hours following a subcutaneous injection of a product containing 100 mg/ml pentosan polysulfate sodium and 168 mg/ml glucosamine. Physical examination revealed the cat to be in hypotensive shock with swelling and interstitial oedema around the cranial thorax and caudal cervical regions without cutaneous haemorrhage. Initial diagnostics revealed a severe anaemia (packed cell volume 11%) which later deteriorated further, necessitating a blood transfusion and aggressive fluid therapy. Post-transfusion, the patient remained dyspnoeic and subsequent diagnostics found evidence of pre-existing cardiomyopathy and congestive heart failure. The cat was euthanased 24 h following presentation due to increasing dyspnoea. Post-mortem findings were of severe subcutaneous and intermuscular haemorrhage over the neck and thorax, among other changes. There were no detectable levels of coumarin anticoagulants in the liver.

Relevance and novel information

This is the first reported case of acute subcutaneous and intermuscular haemorrhage of this severity suspected to be related to the off-label use of an injectable product containing pentosan polysulfate in a cat. Given the popularity of its use for feline arthritis, there is a need for large-scale clinical trials to evaluate the safety and efficacy of products containing pentosan polysulfate for cats, and any side effects to be reported.

Hip disease in Mucopolysaccharidoses and Mucolipidoses: A review of mechanisms, interventions and future perspectives

The hips are frequently involved in inheritable diseases which affect the bones. The clinical and radiological presentation of these diseases may be very similar to common hip disorders as developmental dysplasia of the hip, osteoarthritis and avascular necrosis, so the diagnosis may be easily overlooked and treatment may be suboptimal. Mucopolysaccharidosis (MPS) and Mucolipidosis (ML II and III) are lysosomal storage disorders with multisystemic involvement. Characteristic skeletal abnormalities, known as dysostosis multiplex, are common in MPS and ML and originate from intra-lysosomal storage of glycosaminoglycans in cells of the cartilage, bones and ligaments. The hip joint is severely affected in MPS and ML. Hip pathology results in limitations in mobility and pain from young age, and negatively affects quality of life. In order to better understand the underlying process that causes hip disease in MPS and ML, this review first describes the normal physiological (embryonic) hip joint development, including the interplay between the acetabulum and the femoral head. In the second part the factors contributing to altered hip morphology and function in MPS and ML are discussed, such as abnormal development of the pelvic- and femoral bones (which results in altered biomechanical forces) and inflammation. In the last part of this review therapeutic options and future perspectives are addressed.

Perlecan, a modular instructive proteoglycan with diverse functional properties

This study reviewed some new aspects of the modular proteoglycan perlecan, a colossal proteoglycan with a 467 kDa core protein and five distinct functional domains. Perlecan is a heparan sulphate proteoglycan that transiently displays native CS sulphation motifs 4-C-3 and 7-D-4 during tissue morphogenesis these are expressed by progenitor cell populations during tissue development. Perlecan is susceptible to fragmentation by proteases during tissue development and in pathological tissues particularly in domains IV and V. The fragmentation pattern of domain IV has been suggested as a means of grading prostate cancer. Domain V of perlecan is of interest due to its interactive properties with integrin α5β1 that promotes pericyte migration enhancing PDGF-BB-induced phosphorylation of PDGFRβ, Src homology region 2 domain-containing phosphatase-2, and focal adhesion kinase supporting the repair of the blood brain barrier following ischaemic stroke. Fragments of domain V can also interact with α2β1 integrin disrupting tube formation by endothelial cells. LG1-LG2, LG3 fragments can antagonise VEGFR2, and α2β1 integrin interactions preventing angiogenesis by endothelial cells. These domain V fragments are of interest as potential anti-tumour agents. Perlecan attached to the luminal surfaces of endothelial cells in blood vessels acts as a flow sensor that signals back to endothelial and smooth muscle cells to regulate vascular tone and blood pressure. Perlecan also acts as a flow sensor in the lacuno-canalicular space regulating osteocytes and bone homeostasis. Along with its biomechanical regulatory properties in cartilaginous tissues this further extends the functional repertoire of this amazingly diverse functional proteoglycan.

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.

Evaluation of the Release Kinetics of a Pharmacologically Active Substance from Model Intra-Articular Implants Replacing the Cruciate Ligaments of the Knee

Implants are readily applied as a convenient method of therapy. There is great interest in the prolonged release of active substances from implants. The objective of this work was to evaluate the dissolution kinetics of steroidal anti-inflammatory preparation (SAP) released from novel implants, and to test the influence of the technology on SAP release kinetics. The proposed long-acting preparations may overcome difficulties resulting from repeated injections and often visits to ambulatory clinic, as the stabilizing function of the artificial ligament would be enriched with pharmacological activity. The potential advantages provided by the new coatings of knee implants include the continuous, sustained, and prolonged release of an active substance. The study was carried out using a modified United States Pharmacopoeia (USP) apparatus 4. The amount of SAP was measured spectroscopically. It was revealed that the transport of the drug was mainly a diffusion process. The drug release kinetics was analyzed using zero-, first-, and second-order kinetics as well as Korsmeyer-Peppas, Higuchi, and Hixon-Crowell models. The highest values of the release rate constants were k0 = (7.49 ± 0.05) × 10-5 mg × min-1, k1 = (6.93 ± 0.05) × 10-6 min-1, and k2 = (7.70 ± 0.05) × 10-7 mg-1 × min-1 as calculated according to zero-, first-, and second-order kinetics equations, respectively. The values of the rate constants obtained for the slowest process were k0 = (3.63 ± 0.06) × 10-5 mg × min-1, k1 = (2.50 ± 0.03) × 10-6 min-1, and k2 = (2.80 ± 0.03) × 10-7 mg-1 × min-1. They may suggest the possibility of sustained release of betamethasone from the system. Due to the statistical analysis, differences were observed between most of the studied implants. Incubation, temperature, time of stabilization of layers, and the method of SAP deposition on the matrix affected the drug release.

Anti-arthritic effect of pentosan polysulfate in rats with collagen-induced arthritis

Pentosan polysulfate (PPS) is currently under investigation as a potential disease-modifying antiarthritic agent. In the present study the effects of PPS on arthritic profiles based on clinical score, ankle size, histological changes, and activity of inflammatory mediators using collagen-induced arthritic rat are reported. Model of arthritis was developed in Sprague Dawley rats by intradermal injection of bovine type II collagen emulsified with incomplete Freund's adjuvant. The rats were randomly divided into four groups: normal control, arthritic control, arthritic rats treated with PPS (at dose level 20 μg/g) and arthritic rats treated with meloxicam (2 μg/g). The treatment was continued daily until the day 30. Arthritic biomarkers (cartilage oligomeric matrix protein and tartrate-resistant acid phosphatase 5b) in synovial fluid, expression of inflammatory mediators (interleukin-1β, and tumor necrosis factor-α) and osteoclast marker genes (cathepsin K, tartrate-resistant acid phosphatase) in synovial membrane were measured. Daily administration of PPS to the arthritic rats significantly decreased the severity of arthritis by effectively suppressing the symptoms of arthritis and improving the functional recovery based on clinical score and histopathological evidence. Intriguingly, identical downregulation pattern of arthritis profiles, biological markers as well as relative mRNA levels of osteoclast markers and cytokines were monitored in arthritic rats treated with PPS. In conclusion, PPS exerted protective effects against collagen-induced arthritis in rats. The results suggest that PPS acts as an anti-inflammatory and anti-arthritic agent in decreasing the arthritic effects in collagen-induced arthritic rats.

Inhibitory effects of sodium pentosan polysulfate on formation and function of osteoclasts derived from canine bone marrow

BACKGROUND

Sodium pentosan polysulfate (NaPPS) was testified as a chondroprotective drug in with a detailed rationale of the disease-modifying activity. This study was undertaken to determine whether anti-osteoarthritis drug, NaPPS inhibited osteoclasts (OC) differentiation and function. Canine bone marrow mononuclear cells (n = 6) were differentiated to OC by maintaining with receptor activator of nuclear factor kappa B ligand (RANKL) and macrophage colony-stimulating factor (M-CSF) for up to 7 days with the treatment of NaPPS at concentration of 0, 0.2, 1 and 5 μg/mL. Differentiation and function of OC were accessed using tartrate-resistant acid phosphate (TRAP) staining and bone resorption assay, while monitoring actin ring formation. Invasion and colocalization patterns of fluorescence-labeled NaPPS with transcribed gene in OC were monitored. Gene expression of OC for cathepsin K (CTK), matrix metallopeptidase-9 (MMP-9), nuclear factor of activated T-cells cytoplasmic 1 (NFATc1), c-Fos, activator protein-1(AP-1) and carbonic anhydrase II was examined using real-time PCR.

RESULTS

Significant inhibition of OC differentiation was evident at NaPPS concentration of 1 and 5 μg/mL (p < 0.05). In the presence of 0.2 to 5 μg/mL NaPPS, bone resorption was attenuated (p < 0.05), while 1 and 5 μg/mL NaPPS achieved significant reduction of actin ring formation. Intriguingly, fluorescence-labeled NaPPS invaded in to cytoplasm and nucleus while colocalizing with actively transcribed gene. Gene expression of CTK, MMP-9 and NFATc1 were significantly inhibited at 1 and 5 μg/mL (p < 0.05) of NaPPS whereas inhibition of c-Fos and AP-1 was identified only at concentration of 5 μg/mL (p < 0.05).

CONCLUSIONS

Taken together, all the results suggest that NaPPS is a novel inhibitor of RANKL and M-CSF-induced CTK, MMP-9, NFATc1, c-Fos, AP-1 upregulation, OC differentiation and bone resorption which might be a beneficial for treatment of inflammatory joint diseases and other bone diseases associated with excessive bone resorption.

Mesenchymal progenitor cells primed with pentosan polysulfate promote lumbar intervertebral disc regeneration in an ovine model of microdiscectomy

BACKGROUND CONTEXT

Neural compression associated with lumbar disc herniation is usually managed surgically by microdiscectomy. However, 10%-20% of patients re-present with debilitating back pain, and approximately 15% require further surgery.

PURPOSE

Using an ovine model of microdiscectomy, the present study investigated the relative potential of pentosan polysulfate-primed mesenchymal progenitor cells (pMPCs) or MPC alone implanted into the lesion site to facilitate disc recovery.

STUDY DESIGN

An ovine model of lumbar microdiscectomy was used to compare the relative outcomes of administering MPCs or pMPCs to the injury site postsurgery.

METHODS

At baseline 3T magnetic resonance imaging (MRI) of 18 adult ewes was undertaken followed by annular microdiscectomy at two lumbar disc levels. Sheep were randomized into three groups (n=6). The injured controls received no further treatment. Defects of the treated groups were implanted with a collagen sponge and MPC (5×10⁵ cells) or pMPC (5×10⁵ cells). After 6 months, 3T MRI and standard radiography were performed. Spinal columns were dissected, individual lumbar discs were sectioned horizontally, and nucleus pulposus (NP) and annulus fibrosus (AF) regions were assessed morphologically and histologically. The NP and AF tissues were dissected into six regions and analyzed biochemically for their proteoglycans (PGs), collagen, and DNA content.

RESULTS

Both the MPC- and pMPC-injected groups exhibited less reduction in disc height (p<.05) and lower Pfirrmann grades (p≤.001) compared with the untreated injury controls, but morphologic scores for the pMPC-injected discs were lower (p<.05). The PG content of the AF injury site region (AF1) of pMPC discs was higher than MPC and injury control AF1 (p<.05). At the AF1 and contralateral AF2 regions, the DNA content of pMPC discs was significantly lower than injured control discs and MPC-injected discs. Histologic and birefringent microscopy revealed increased structural organization and reduced degeneration in pMPC discs compared with MPC and the injured controls.

CONCLUSIONS

In an ovine model 6 months after administration of pMPCs to the injury site disc PG content and matrix organization were improved relative to controls, suggesting pMPCs' potential as a postsurgical adjunct for limiting progression of disc degeneration after microdiscectomy.

Erosion of the medial compartment of the canine elbow: occurrence, diagnosis and currently available treatment options

Erosion of the medial compartment of the elbow joint refers to full thickness cartilage loss with exposure of the subchondral bone (modified Outerbridge grades 4–5) of the medial part of the humeral condyle (MHC) and the corresponding ulnar contact area. This finding may appear in the absence of an osteochondral fragment or a cartilage flap, or in combination with fragmentation of the medial coronoid process (MCP) or osteochondritis dissecans (OCD) of the MHC. With regard to the prognosis, it is important to diagnose these severe erosions. Imaging of cartilage lesions by means of radiography, ultrasonography, computed tomography or magnetic resonance imaging is challenging in dogs. In contrast, direct arthroscopic inspection provides detailed information about the cartilage.

The treatment of these severe erosions is difficult because of the limited regenerative capacity of cartilage and presumed mechanical or physical triggering factors. Several conservative and surgical treatment methods have been proposed to treat elbows with severe cartilage defects. However, due to irreversible loss of cartilage, the prognosis in these cases remains guarded.

Pentosan polysulfate binds to STRO-1+ mesenchymal progenitor cells, is internalized, and modifies gene expression: a novel approach of pre-programing stem cells for therapeutic application requiring their chondrogenesis

BACKGROUND

The pharmaceutical agent pentosan polysulfate (PPS) is known to induce proliferation and chondrogenesis of mesenchymal progenitor cells (MPCs) in vitro and in vivo. However, the mechanism(s) of action of PPS in mediating these effects remains unresolved. In the present report we address this issue by investigating the binding and uptake of PPS by MPCs and monitoring gene expression and proteoglycan biosynthesis before and after the cells had been exposed to limited concentrations of PPS and then re-established in culture in the absence of the drug (MPC priming).

METHODS

Immuno-selected STRO-1+ mesenchymal progenitor stem cells (MPCs) were prepared from human bone marrow aspirates and established in culture. The kinetics of uptake, shedding, and internalization of PPS by MPCs was determined by monitoring the concentration-dependent loss of PPS media concentrations using an enzyme-linked immunosorbent assay (ELISA) and the uptake of fluorescein isothiocyanate (FITC)-labelled PPS by MPCs. The proliferation of MPCs, following pre-incubation and removal of PPS (priming), was assessed using the Wst-8 assay method, and proteoglycan synthesis was determined by the incorporation of 35SO4 into their sulphated glycosaminoglycans. The changes in expression of MPC-related cell surface antigens of non-primed and PPS-primed MPCs from three donors was determined using flow cytometry. RNA sequencing of RNA isolated from non-primed and PPS-primed MPCs from the same donors was undertaken to identify the genes altered by the PPS priming protocol.

RESULTS

The kinetic studies indicated that, in culture, PPS rapidly binds to MPC surface receptors, followed by internalisation and localization within the nucleus of the cells. Following PPS-priming of MPCs and a further 48 h of culture, both cell proliferation and proteoglycan synthesis were enhanced. Reduced expression of MPC-related cell surface antigen expression was promoted by the PPS priming, and RNA sequencing analysis revealed changes in the expression of 42 genes.

CONCLUSION

This study has shown that priming of MPCs with low concentrations of PPS enhanced chondrogenesis and MPC proliferation by modifying their characteristic basal gene and protein expression. These findings offer a novel approach to re-programming mesenchymal stem cells for clinical indications which require the repair or regeneration of cartilaginous tissues such as in osteoarthritis and degenerative disc disease.

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.

Reconstitution of degenerated ovine lumbar discs by STRO-3-positive allogeneic mesenchymal precursor cells combined with pentosan polysulfate

OBJECTIVE Disc degeneration and associated low-back pain are major causes of suffering and disability. The authors examined the potential of mesenchymal precursor cells (MPCs), when formulated with pentosan polysulfate (PPS), to ameliorate disc degeneration in an ovine model. METHODS Twenty-four sheep had annular incisions made at L2-3, L3-4, and L4-5 to induce degeneration. Twelve weeks after injury, the nucleus pulposus of a degenerated disc in each animal was injected with ProFreeze and PPS formulated with either a low dose (0.1 million MPCs) or a high dose (0.5 million MPCs) of cells. The 2 adjacent injured discs in each spine were either injected with PPS and ProFreeze (PPS control) or not injected (nil-injected control). The adjacent noninjured L1-2 and L5-6 discs served as noninjured control discs. Disc height indices (DHIs) were obtained at baseline, before injection, and at planned death. After necropsy, 24 weeks after injection, the spines were subjected to MRI and morphological, histological, and biochemical analyses. RESULTS Twelve weeks after the annular injury, all the injured discs exhibited a significant reduction in mean DHI (low-dose group 17.19%; high-dose group 18.01% [p < 0.01]). Twenty-four weeks after injections, the discs injected with the low-dose MPC+PPS formulation recovered disc height, and their mean DHI was significantly greater than the DHI of PPS- and nil-injected discs (p < 0.001). Although the mean Pfirrmann MRI disc degeneration score for the low-dose MPC+PPS-injected discs was lower than that for the nil- and PPS-injected discs, the differences were not significant. The disc morphology scores for the nil- and PPS-injected discs were significantly higher than the normal control disc scores (p < 0.005), whereas the low-dose MPC+PPS-injected disc scores were not significantly different from those of the normal controls. The mean glycosaminoglycan content of the nuclei pulposus of the low-dose MPC+PPS-injected discs was significantly higher than that of the PPS-injected controls (p < 0.05) but was not significantly different from the normal control disc glycosaminoglycan levels. Histopathology degeneration frequency scores for the low-dose MPC+PPS-injected discs were lower than those for the PPS- and Nil-injected discs. The corresponding high-dose MPC+PPS-injected discs failed to show significant improvements in any outcome measure relative to the controls. CONCLUSIONS Intradiscal injections of a formulation composed of 0.1 million MPCs combined with PPS resulted in positive effects in reducing the progression of disc degeneration in an ovine model, as assessed by improvements in DHI and morphological, biochemical, and histopathological scores.

Survey of the therapeutic approach and efficacy of pentosan polysulfate for the prevention and treatment of equine osteoarthritis in veterinary practice in Australia

OBJECTIVE

To survey veterinary practitioners in Australia on how they administer pentosan polysulfate (PPS) to horses and their perceptions of the efficacy of PPS for: the prevention and treatment of osteoarthritis (OA), the treatment of OA when PPS is combined with other drugs, and the efficacy of PPS compared with other disease-modifying osteoarthritic drugs.

DESIGN

Practitioners were contacted by email, which contained a link to an online survey.

RESULTS

A total of 76 responses (34.5%) to the survey were received. Respondents most commonly used PPS as prophylactic therapy prior to competition (80.3%). As a prophylactic agent, PPS was considered by 48.2% of respondents to have high efficacy. The most common dose regimen for prevention and treatment of OA was 3 mg/kg, intramuscularly, once weekly for 4 weeks followed by monthly injections. Most respondents (78%) combined PPS with other drugs for treatment of OA. Intra-articular corticosteroids and hyaluronate (HA) was the most common drug combination used with PPS. PPS was preferred as a prophylactic agent when compared with HA (88.7% vs 11.3%). For treating OA, 83% of respondents considered a combination of PPS, HA and glucosamine to be more efficacious than PPS alone. However, the most common reason not to use this combination was cost (79.1%).

CONCLUSION

All respondents used PPS for prophylaxis and/or treatment of OA despite limited published scientific evidence proving its efficacy in horses. Further research is necessary to provide evidence of the clinical efficacy of PPS for the prevention and treatment of OA in horses.

Anti-Osteoarthritic Effects of the Litsea japonica Fruit in a Rat Model of Osteoarthritis Induced by Monosodium Iodoacetate

Osteoarthritis (OA) is a degenerative chronic disease that affects various tissues surrounding the joints, such as the subchondral bone and articular cartilage. The onset of OA is associated with uncontrolled catabolic and anabolic remodeling processes of the joints, including the cartilage and subchondral bone, to adapt to local biological and biochemical signals. In this study, we determined whether 70% ethanolic (EtOH) extract of Litsea japonica fruit (LJFE) had beneficial effects on the articular cartilage, including structural changes in the tibial subchondral bone, matrix degradation, and inflammatory responses, in OA by using a rat model of monosodium iodoacetate-induced OA. Our results showed that administration of LJFE increased the bone volume and cross-section thickness, but the mean number of objects per slice in this group was lower than that in the OA control (OAC) group. In addition, the LJFE decreased the expression of inflammatory cytokines. Compared to the OAC group, the group treated with high doses of LJFE (100 and 200 mg/kg) showed a more than 80% inhibition of the expression of matrix metalloproteinases and tissue inhibitors of metalloproteinases. Our results suggest that LJFE can be used as a potential anti-osteoarthritic agent.

Pentosan Polysulfate: a Novel Glycosaminoglycan-Like Molecule for Effective Treatment of Alphavirus-Induced Cartilage Destruction and Inflammatory Disease

Arthritogenic alphaviruses such as Ross River virus (RRV) and chikungunya virus (CHIKV) cause large-scale epidemics of severe musculoskeletal disease and have been progressively expanding their global distribution. Since its introduction in July 2014, CHIKV now circulates in the United States. The hallmark of alphavirus disease is crippling pain and inflammation of the joints, a similar immunopathology to rheumatoid arthritis. The use of glycans as novel therapeutics is an area of research that has increased in recent years. Here, we describe the promising therapeutic potential of the glycosaminoglycan (GAG)-like molecule pentosan polysulfate (PPS) to alleviate virus-induced arthritis. Mouse models of RRV and CHIKV disease were used to characterize the extent of cartilage damage in infection and investigate the potential of PPS to treat disease. This was assessed using histological analysis, real-time PCR, and fluorescence-activated cell sorting (FACS). Alphaviral infection resulted in cartilage destruction, the severity of which was alleviated by PPS therapy during RRV and CHIKV clinical disease. The reduction in cartilage damage corresponded with a significant reduction in immune infiltrates. Using multiplex bead arrays, PPS treatment was found to have significantly increased the anti-inflammatory cytokine interleukin-10 and reduced proinflammatory cytokines, typically correlated with disease severity. Furthermore, we reveal that the severe RRV-induced joint pathology, including thinning of articular cartilage and loss of proteoglycans in the cartilage matrix, was diminished with treatment. PPS is a promising new therapy for alphavirus-induced arthritis, acting to preserve the cartilage matrix, which is damaged during alphavirus infection. Overall, the data demonstrate the potential of glycotherapeutics as a new class of treatment for infectious arthritis.

IMPORTANCE

The hallmark of alphavirus disease is crippling pain and joint arthritis, which often has an extended duration. In the past year, CHIKV has expanded into the Americas, with approximately 1 million cases reported to date, whereas RRV continues to circulate in the South Pacific. Currently, there is no licensed specific treatment for alphavirus disease, and the increasing spread of infection highlights an urgent need for therapeutic intervention strategies. Pentosan polysulfate (PPS) is a glycan derivative that is orally bioavailable, has few toxic side effects, and is currently licensed under the name Elmiron for the treatment of cystitis in the United States. Our findings show that RRV infection damages the articular cartilage, including a loss of proteoglycans within the joint. Furthermore, treatment with PPS reduced the severity of both RRV- and CHIKV-induced musculoskeletal disease, including a reduction in inflammation and joint swelling, suggesting that PPS is a promising candidate for drug repurposing for the treatment of alphavirus-induced arthritis.

Dose responsive effects of subcutaneous pentosan polysulfate injection in mucopolysaccharidosis type VI rats and comparison to oral treatment

BACKGROUND

We previously demonstrated the benefits of daily, oral pentosan polysulfate (PPS) treatment in a rat model of mucopolysaccharidosis (MPS) type VI. Herein we compare these effects to once weekly, subcutaneous (s.c.) injection. The bioavailability of injected PPS is greater than oral, suggesting better delivery to difficult tissues such as bone and cartilage. Injected PPS also effectively treats osteoarthritis in animals, and has shown success in osteoarthritis patients.

METHODOLOGY/PRINCIPAL FINDINGS

One-month-old MPS VI rats were given once weekly s.c. injections of PPS (1, 2 and 4 mg/kg, human equivalent dose (HED)), or daily oral PPS (4 mg/kg HED) for 6 months. Serum inflammatory markers and total glycosaminoglycans (GAGs) were measured, as were several histological, morphological and functional endpoints. Overall, weekly s.c. PPS injections led to similar or greater therapeutic effects as daily oral administration. Common findings between the two treatment approaches included reduced serum inflammatory markers, improved dentition and skull lengths, reduced tracheal deformities, and improved mobility. Enhanced effects of s.c. treatment included GAG reduction in urine and tissues, greater endurance on a rotarod, and better improvements in articular cartilage and bone in some dose groups. Optimal therapeutic effects were observed at 2 mg/kg, s.c.. No drug-related increases in liver enzymes, coagulation factor abnormalities or other adverse effects were identified following 6 months of s.c. PPS administration.

CONCLUSIONS

Once weekly s.c. administration of PPS in MPS VI rats led to equal or better therapeutic effects than daily oral administration, including a surprising reduction in urine and tissue GAGs. No adverse effects from s.c. PPS administration were observed over the 6-month study period.

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.

Effects of pentosan polysulfate in osteoarthritis of the knee: A randomized, double-blind, placebo-controlled pilot study

BACKGROUND

Recent recommendations from the Group for the Respect of Excellence and Ethics in Science for the clinical assessment of the effects of disease-modifying osteoarthritis (OA) drugs suggest that improvement in joint space narrowing, pain, and function relative to a control group should be the primary end points.

OBJECTIVE

The aim of this study was to assess the ability of sodium pentosan polysulfate (NaPPS) to improve pain and function in patients with OA of the knee.

METHODS

This randomized, double-blind, placebo-controlled pilot study was performed at the Queen Elizabeth II Medical Centre, Perth, Australia. Patients aged ≥18 years with OA of the knee were randomly assigned to receive NaPPS 3 mg/kg or Ringer's solution (control), IM QW for 4 weeks. Efficacy was assessed at enrollment and weekly during the 4 weeks of treatment and at weeks 8, 12, 16, and 24. Seven direct clinical assessments were made, including intensity of early morning joint stiffness, pain at rest, and pain on walking. A 10-cm visual analog scale (VAS) was used to assess pain at rest and on walking and early morning joint stiffness. Response was defined as a change from baseline in VAS score ≥2 cm. Function was assessed using the 10-cm VAS to rate 13 activities of daily living (ADLs), including stair climbing and domestic chores. Patient global assessment of the overall effectiveness of the study drug comprised a 4-point Likert scale (0 = not effective to 3 = maximally effective). An aggregate score for all ADL functions was calculated as the mean change from baseline score of all of the ADLs as determined at 4, 8, 12, 16, and 24 weeks after commencement of the study. For tolerability monitoring, hematology and biochemistry were used, and patients were questioned about adverse events at each visit.

RESULTS

A total of 114 patients were enrolled (83 women, 31 men; mean [SD] age, 63.3 [1.5] years; NaPPS group, 54 patients; control group, 60 patients). Significant differences in scores of 3 of the 7 direct clinical assessments were found between the 2 groups (duration of joint stiffness at 4, 8, 12, and 16 weeks [all, P:5 0.015]; pain at rest at 8, 12, 16, and 24 weeks [all, P ≤ 0.017]; and patient global assessment at 4, 8, 12, 16, and 24 weeks [all, P <- 0.006]). The rates of trial continuation were higher in the NaPPS group compared with those in the control group at 8, 12, and 24 weeks (all, P < 0.05). Mean scores for 3 of 13 ADLs were significantly higher in the NaPPS group compared with those in the control group at weeks 8 and 12 (all, P ≤ 0.03). On combining all of the ADL scores, functional improvement from baseline was found at weeks 8 and 12 in the NaPPS group (both, P = 0.02). Mild bruising at the injection site occurred in <1% of patients in both treatment groups.

CONCLUSIONS

In this pilot study, 4 weekly injections of NaPPS were associated with significantly improved duration of joint stiffness and pain at rest compared with controls for 20 weeks after the cessation of treatment, and significantly improved pain on walking and overall function for 8 weeks after the cessation of treatment in these patients with OA of the knee.

Therapeutic options for the treatment of chronic pain in dogs

Chronic pain is a widely recognised problem in humans and is being increasingly recognised as a significant problem in dogs. Whilst a large number of therapies are described and utilised to treat chronic pain in dogs, there is a severe shortage of evidence to guide practitioners in selection of treatments. Until more evidence becomes available, practitioners should adopt a cautious approach, utilising licensed treatments first when possible. Non-pharmacological therapies should be incorporated into the chronic pain management plan whenever possible. Given the probable prevalence of chronic pain in dogs there is an urgent need for research to identify effective treatments.

Pentosan polysulfate: a novel therapy for the mucopolysaccharidoses

Background

Pentosan polysulfate (PPS) is an FDA-approved, oral medication with anti-inflammatory and pro-chondrogenic properties. We have previously shown that animal models of the mucopolysaccharidoses (MPS) exhibit significant inflammatory disease, contributing to cartilage degeneration. Enzyme replacement therapy (ERT) only partly reduced inflammation, and anti-TNF-alpha antibody therapy significantly enhanced clinical and pathological outcomes. Here we describe the use of PPS for the treatment of MPS type VI rats.

Methodology/Principal Findings

Treatment began during prenatal development and at 1 and 6 months of age. All animals were treated until they were 9 months old. Significant reductions in the serum and tissue levels of several inflammatory markers (e.g., TNF-alpha, MIP-1alpha and RANTES/CCL5) were observed, as was reduced expression of inflammatory markers in cultured articular chondrocytes. ADAMTS-5/aggrecanase-2 levels also were reduced in chondrocytes, consistent with an elevation of serum tissue inhibitor of metalloproteinase 1. Marked improvements in motility and grooming behavior occurred, along with a reduction in eye and nasal secretions and a lessening of the tracheal deformities. MicroCT and radiographic analyses further revealed that the treated MPS skulls were longer and thinner, and that the teeth malocclusions, misalignments and mineral densities were improved. MicroCT analysis of the femurs and vertebrae revealed improvements in trabecular bone mineral densities, number and spacing in a subset of treated MPS animals. Biomechanical assessments of PPS-treated spines showed partially restored torsional behaviors, suggesting increased spinal stability. No improvements were observed in cortical bone or femur length. The positive changes in the PPS-treated MPS VI rats occurred despite glycosaminoglycan accumulation in their tissues.

Conclusions

Based on these findings we conclude that PPS could be a simple and effective therapy for MPS that might provide significant clinical benefits alone and in combination with other therapies.

Chondrogenesis on sulfonate-coated hydrogels is regulated by their mechanical properties

Many studies have demonstrated that sulfur-containing acidic groups induce chondrogenesis in vitro and in vivo. Recently, it is increasingly clear that mechanical properties of cell substrates largely influence cell differentiation. Thus, the present study investigated how mechanical properties of sulfonate-coated hydrogels influences chondrogenesis of mesenchymal stem cells (MSCs). Sulfonate-coated polyacrylamide gels (S-PAAm gels) which have the elastic modulus, E, of about 1, 15 and 150 kPa, were used in this study. MSCs cultured on the high stiffness S-PAAm gels (E=∼150 kPa) spread out with strong expression of stress fibers, while MSCs cultured on the low stiffness S-PAAm gels (E=∼1 kPa) had round shapes with less stress fibers but more cortical actins. Importantly, even in the absence of differentiation supplements, the lower stiffness S-PAAm gels led to the higher mRNA levels of chondrogenic markers such as Col2a1, Agc and Sox9 and the lower mRNA levels of an undifferentiation marker Sca1, indicating that the mechanical properties of S-PAAm gels strongly influence chondrogenesis. Blebbistatin which blocks myosin II-mediated mechanical sensing suppressed chondrogenesis induced by the low stiffness S-PAAm gels. The present study demonstrates that the soft S-PAAm gels effectively drive MSC chondrogenesis even in the absence of soluble differentiation factors and thus suggests that sulfonate-containing hydrogels with low stiffness could be a powerful tool for cartilage regeneration.

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

Pentosan polysulfate sodium (PPS) has a heparin-like structure and is purificated from the plant of European beech wood. PPS has been used for the treatment of interstitial cystitis for human patients. Recent years, it was newly recognised that PPS reduce pain and inflammation of OA. The molecular biological mechanism of PPS to express its clinical effects is not fully understood. The purpose of the present study is to investigate a mechanism of action of PPS on inflammatory reaction of chondrocytes in vitro. It was evaluated that effects of PPS on interleukin (IL)-1β-induced phosphorylation of mitogen-actiated protein kinases (MAPKs), such as p38, extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK), nuclear translocation of nuclear factor-kappa B (NF-κB), and matrix metalloproteinase (MMP)-3 production in cultured articular chondrocytes. As a result, in the presence of PPS existence, IL-1β-induced phosphorylation of p38 and ERK were certainly inhibited, while JNK phosphorylation was not affected. Nuclear translocation of NF-κB and MMP-3 production were suppressed by PPS pretreatment prior to IL-1β stimulation. In conclusion, it is strongly suggested that PPS treatment prevents inflammatory intracellular responses induced by IL-1 β through inhibition of phosphorylation of certain MAPKs, p38 and ERK and then nuclear translocation of NF-κB in cultured chondrocytes. These PPS properties may contribute to suppressive consequence of catabolic MMP-3 synthesis. These data might translate the clinical efficacy as PPS treatment could inhibit the cartilage catabolism and related clinical symptoms of OA in dogs.

Xylan and Xylan Derivatives – Basis of Functional Polymers for the Future

This review highlights xylan and xylan derivatives. It depicts the occurrence and structural diversity of the biopolymer, followed by a presentation of different ways of isolation from biomass. The determination of characteristics, i.e., molecular weight, interaction with other polysaccharides, thermal behaviour, and the biological activity of xylan are reviewed. The application potential arising from the structural features of the unmodified xylan is pointed out. Special attention is concentrated on the possibilities of the modification of functional properties by chemical functionalization of the biopolymers in order to design advanced materials. Within this review recent results in the field are accompanied with selected results of our own work.

Pentosan reduces osteonecrosis of femoral head in SHRSP

Increased oxidative stress is considered one of the main causes of steroid-induced osteonecrosis of the femoral head (ONFH). The aim of this study was to evaluate the effects of a steroid hormone and pentosan polysulfate sodium (pentosan), a heparin analog, in stroke-prone spontaneously hypertensive rats (SHRSP) as a model of ONFH. One hundred twenty-three 13-week-old male SHRSP/Izm rats were divided into four groups: a control group (group C), pentosan-administered group (group P), steroid-administered group (group S), and group administered pentosan plus steroid (group PS). Methylprednisolone acetate, as the steroid hormone, at a dose of 4 mg (15 mg/kg) was administered at 15 weeks of age. Pentosan at a dose of 3 mg/day/kg was continuously administered intraperitoneally from 13 weeks of age for 4 weeks. Rats were sacrificed at 17 weeks of age, and heart blood and both femora were collected. Triglyceride levels were significantly lower in group PS than in group S, indicating that pentosan improves lipid metabolism. The incidence of histologic ONFH was significantly lower in group P, at 14.8% (10/71 femoral heads), than in group C, at 30.4% (17/56 femoral heads), and significantly lower in group PS, at 40.8% (29/71 femoral heads), than in group S, at 91.3% (42/46 femoral heads), indicating that pentosan markedly inhibits ONFH. Immunohistochemical staining for oxidative stress showed that the stainability was significantly lower in group PS than in group S. Pentosan seems to reduce the incidence of ONFH in SHRSP by improving lipid metabolism and decreasing oxidative stress.

Calcium pentosan polysulfate and sodium pentosan polysulfate may be used to treat intervertebral disc degeneration

Intervertebral disc degeneration (IDD) is a major health problem world-wide, and several spinal disorders are closely associated with it. Although people have invested a great deal of time and effort, how to prevent and reverse the IDD for the researchers is still a difficult and hot issue. Intervertebral disc belongs to cartilage tissue, and IDD also is the cartilage degeneration disease. A large quantity of studies have shown that Calcium pentosan polysulfate (CaPPS) and sodium pentosan polysulfate (NaPPS) possess chondroprotective activities and play an important role in maintaining cartilage integrity. We reasonably hypothesize that NaPPS and CaPPS may be used to treat IDD. The possible mechanism may include that: (1) the significant effects of NaPPS and CaPPS in improving capillary blood flow could maintain nutritional supply to intervertebral disc, and preserve intervertebral disc tissue against degeneration; (2) CaPPS and NaPPS preserve cartilage integrity, proteoglycan synthesis, and improve cartilage biomechanical properties; (3) as the multifaceted exosite inhibitors of proteinases NaPPS and CaPPS strongly impede the activity and production of proteinases; (4) promotion of the balance between proteinases and TIMPs also may be involved in treating IDD; (5) NaPPS and CaPPS exhibit potent anti-inflammatory effects, and then reduce inflammation-induced IDD. If the hypothesis were conformed, the symptoms caused by IDD and its related diseases would be a corresponding alleviation or even disappearance, which could greatly alleviate the suffering of patients from disc degeneration diseases. Certainly, many roles of CaPPS and NaPPS, such as effectiveness, safety and side effects, need to be tested, and further works such as animal model and clinical trial, need to be done to prove this hypothesis.

Chondrogenesis of human mesenchymal stem cells in fibrin constructs evaluated in vitro and in nude mouse and rabbit defects models

In this study, hMSCs encapsulated in a fibrin hydrogel containing heparinized NPs loaded with TGF-β3 (100 ng/ml), or TGF-β3 (100 ng/ml) alone, were subjected to growth factor release and denaturation tests at one, two and four weeks in in vitro culture systems. Additionally, stem cell differentiation was assessed via RT-PCR, real-time quantitative PCR (qPCR), histology, and immunohistochemical assays. In the in vivo studies with nude mouse, when transplanted into nude mice, hMSCs embedded in fibrin hydrogels survived and proliferated more readily in those samples containing TGF-β3-loaded NPs, or TGF-β3 alone, compared to those containing only NPs or the fibrin hydrogel alone. Additionally, RT-PCR, real-time qPCR, histology, Western blotting, and immunohistochemistry analyses revealed that chondrocyte-specific extracellular matrix (ECM) genes and their proteins were expressed at high levels by hMSCs embedded in hydrogels containing TGF-β3-loaded NPs. Finally, the results observed in the rabbit animal model treated with hMSCs embedded in a fibrin hydrogel containing TGF-β3-loaded NPs were also evaluated by the RT-PCR, real-time qPCR, histology, Western blotting, and immunohistochemistry analyses. The in vitro and in vivo results indicated that transplanted hMSCs together with TGF-β3 may constitute a clinically efficient method for the regeneration of hyaline articular cartilage.

Cervical motion preservation using mesenchymal progenitor cells and pentosan polysulfate, a novel chondrogenic agent: preliminary study in an ovine model

Object

There is an unmet need for a procedure that could generate a biological disc substitute while at the same time preserving the normal surgical practice of achieving anterior cervical decompression. The objective of the present study was to test the hypothesis that adult allogeneic mesenchymal progenitor cells (MPCs) formulated with a chondrogenic agent could synthesize a cartilaginous matrix when implanted into a biodegradable carrier and cage, and over time, might serve as a dynamic interbody spacer following anterior cervical discectomy (ACD).

Methods

Eighteen ewes were divided randomly into 3 groups of 6 animals. Each animal was subjected to C3–4 and C4–5 ACD followed by implantation of bioresorbable interbody cages and graft containment plates. The cage was packed with 1 of 3 implants. In Group A, the implant was Gelfoam sponge only. In Group B, the implant consisted of Gelfoam sponge with 1 million MPCs only. In Group C, the implant was Gelfoam sponge with 1 million MPCs formulated with the chondrogenic agent pentosan polysulfate (PPS). In each animal the cartilaginous endplates were retained intact at 1 level, and perforated in a standardized manner at the other level. Allogeneic ovine MPCs were derived from a single batch of immunoselected and culture-expanded MPCs isolated from bone marrow of outbred sheep (mixed stock). Radiological and histological measures were used to assess cartilage formation and the presence or absence of new bone formation.

Results

The MPCs with or without PPS were safe and well-tolerated in the ovine cervical spine. There was no significant difference between groups in the radiographic or histological outcome measures, regardless of whether endplates were perforated or retained intact. According to CT scans obtained at 3 months after the operation, new bone formation within the interbody space was observed in the Gelfoam only group (Group A) in 9 (75%) of 12 interbody spaces, and 11 (92%) of 12 animals in the MPC cohort (Group B) had new bone formation within the interbody space. Significantly, in the MPC & PPS group (Group C), there were only 1 (8%) of 12 levels with new bone formation (p = 0.0009 vs Group A; p = 0.0001 vs Group B). According to histological results, there was significantly more cartilaginous tissue within the interbody cages of Group C (MPC & PPS) compared with both the control group (Group A; p = 0.003) and the MPC Group (p = 0.017).

Conclusions

This study demonstrated the feasibility of using MPCs in combination with PPS to produce cartilaginous tissue to replace the intervertebral disc following ACD. This biological approach may offer a means preserving spinal motion and offers an alternative to fusion to artificial prostheses.