Oral salmon calcitonin reduces Lequesne's algofunctional index scores and decreases urinary and serum levels of biomarkers of joint metabolism in knee osteoarthritis

Transcript-dependent effects of the CALCA gene on the progression of post-traumatic osteoarthritis in mice

Osteoarthritis represents a chronic degenerative joint disease with exceptional clinical relevance. Polymorphisms of the CALCA gene, giving rise to either a procalcitonin/calcitonin (PCT/CT) or a calcitonin gene-related peptide alpha (αCGRP) transcript by alternative splicing, were reported to be associated with the development of osteoarthritis. The objective of this study was to investigate the role of both PCT/CT and αCGRP transcripts in a mouse model of post-traumatic osteoarthritis (ptOA). WT, αCGRP-/- and CALCA-/- mice were subjected to anterior cruciate ligament transection (ACLT) to induce ptOA of the knee. Mice were sacrificed 4 and 8 weeks post-surgery, followed by micro-CT and histological evaluation. Here we show that the expression of both PCT/CT and αCGRP transcripts is induced in ptOA knees. CALCA-/- mice show increased cartilage degeneration and subchondral bone loss with elevated osteoclast numbers compared to αCGRP-/- and WT mice. Osteophyte formation is reduced to the same extent in CALCA-/- and αCGRP-/- mice compared to WT controls, while a reduced synovitis score is noticed exclusively in mice lacking CALCA. Our data show that expression of the PCT/CT transcript protects from the progression of ptOA, while αCGRP promotes osteophyte formation, suggesting that CALCA-encoded peptides may represent novel targets for the treatment of ptOA.

Emerging microfluidics-enabled platforms for osteoarthritis management: from benchtop to bedside

Osteoarthritis (OA) is a prevalent debilitating age-related joint degenerative disease. It is a leading cause of pain and functional disability in older adults. Unfortunately, there is no cure for OA once the damage is established. Therefore, it promotes an urgent need for early detection and intervention of OA. Theranostics, combining therapy and diagnosis, emerges as a promising approach for OA management. However, OA theranostics is still in its infancy. Three fundamental needs have to be firstly fulfilled: i) a reliable OA model for disease pathogenesis investigation and drug screening, ii) an effective and precise diagnostic platform, and iii) an advanced fabrication approach for drug delivery and therapy. Meanwhile, microfluidics emerges as a versatile technology to address each of the needs and eventually boost the development of OA theranostics. Therefore, this review focuses on the applications of microfluidics, from benchtop to bedside, for OA modelling and drug screening, early diagnosis, and clinical therapy. We first introduce the basic pathophysiology of OA and point out the major unfilled research gaps in current OA management including lack of disease modelling and drug screening platforms, early diagnostic modalities and disease-modifying drugs and delivery approaches. Accordingly, we then summarize the state-of-the-art microfluidics technology for OA management from in vitro modelling and diagnosis to therapy. Given the existing promising results, we further discuss the future development of microfluidic platforms towards clinical translation at the crossroad of engineering and biomedicine.

Blood and urine biomarkers in osteoarthritis - an update on cartilage associated type II collagen and aggrecan markers

PURPOSE OF REVIEW

Osteoarthritis (OA) is a painful disease for which drug development has proven difficult. One major reason for this is the heterogeneity of the disease and the current lack of operationalized means to distinguish various disease endotypes (molecular subtypes). Biomarkers measured in blood or urine, reflecting joint tissue turnover, have been developed and tested during the last decades. In this narrative review, we provide highlights on biomarkers derived from the two most studied and abundant cartilage proteins - type II collagen and aggrecan.

RECENT FINDINGS

Multiple biomarkers assessing type II collagen degradation and formation, and aggrecan turnover have been developed. Several markers, such as uCTX-II, have been validated for their association with disease severity and prognosis, as well as pharmacodynamically used to describe the mode of action and efficacy of drugs in development. There is a great need for biomarkers for subdividing patients (i.e., endotyping) and recent scientific advances have not yet come closer to achieving this goal.

SUMMARY

There is strong support for using biomarkers for understanding OA, reflecting degradation and formation of the joint tissues, focused on type II collagen and aggrecan. There is still a lack of in vitro diagnostics, in all contexts of use.

Drug delivery in intervertebral disc degeneration and osteoarthritis: Selecting the optimal platform for the delivery of disease-modifying agents

Osteoarthritis (OA) and intervertebral disc degeneration (IVDD) as major cause of chronic low back pain represent the most common degenerative joint pathologies and are leading causes of pain and disability in adults. Articular cartilage (AC) and intervertebral discs are cartilaginous tissues with a similar biochemical composition and pathophysiological aspects of degeneration. Although treatments directed at reversing these conditions are yet to be developed, many promising disease-modifying drug candidates are currently under investigation. Given the localized nature of these chronic diseases, drug delivery systems have the potential to enhance therapeutic outcomes by providing controlled and targeted release of bioactives, minimizing the number of injections needed and increasing drug concentration in the affected areas. This review provides a comprehensive overview of the currently most promising disease-modifying drugs as well as potential drug delivery systems for OA and IVDD therapy.

Clinical effect of intramuscular calcitonin compared with oral celecoxib in the treatment of knee bone marrow lesions: a retrospective study

BACKGROUND

Bone marrow lesions (BMLs) are a common finding in patients with osteoarthritis (OA), which are predictors of progression and pain related to cartilage damage in OA. The objective of the present research was to compare the short-term clinical effect of intramuscular calcitonin and oral celecoxib in treating knee BMLs.

PATIENTS AND METHODS

Between January 2016 and December 2018, the medical records of patients with knee BMLs treated by intramuscular calcitonin or oral celecoxib were reviewed. Visual analog scale (VAS) and the Western Ontario and McMaster University Osteoarthritis Index (WOMAC) were used to assess knee pain and function, respectively. BMLs were assessed by MRI scans and were scored by the modified Whole-Organ MRI Score (WORMS). The safety of these two medications was also evaluated.

RESULTS

A total of 123 eligible patients who received calcitonin treatment (n = 66) or celecoxib treatment (n = 57) were included. All patients were followed up clinically and radiographically for 3 months. The VAS and WOMAC scores were lower statistically in calcitonin group than celecoxib group at 4-week and 3-month follow-up. For BMLs, the WORMS scores in the calcitonin group were significantly lower than the celecoxib group. Besides, statistically higher MRI improvement rates were found in the calcitonin group compared with the celecoxib group at 4-week follow-up (21.21% vs. 7.01%; P = 0.039) and 3-month follow-up (37.88% vs. 15.79%; P = 0.006).

CONCLUSION

Intramuscular calcitonin 50 IU once daily demonstrated a better short-term effect for knee BML patients compared with oral celecoxib 200 mg twice per day.

Blood and urinary collagen markers in osteoarthritis: markers of tissue turnover and disease activity

Introduction: The need for diagnostic markers in osteoarthritis (OA) is acute and immediate, as sensitive and precise tools that monitor disease activity and treatment response are lacking. Collagens - types I, II, and III - are the skeleton of the extracellular matrix of joint tissues. Joint collagens are generally turned over at a low rate, but the balance between formation and degradation is disturbed, leading to the loss of, for example, cartilage.Areas covered: We discuss the markers reflecting collagen turnover and provide examples of how they have been applied in OA research, as well as how we believe these should be used in the future. We have searched PubMed for full-text articles written in English using different combinations of the following terms: OA, biomarker, and collagen. The result is a narrative review that gives examples from the literature.Expert opinion: Collagen markers show promise, as they are direct measures of tissue balance. Until now, collagen markers have mainly been tested in observational cohorts, which may provide insights into the association between the candidate marker and clinical variables; however, these do not advance the development of qualified markers that can be used for drug development or in clinical practice.

Salmon calcitonin exerts better preventive effects than celecoxib on lumbar facet joint degeneration and long-term tactile allodynia in rats

OBJECTIVE

To evaluate and compare the effects of salmon calcitonin (sCT) and celecoxib (CLX) on cartilage, subchondral bone and tactile allodynia in a rat model of lumbar facet joint (FJ) osteoarthritis (OA).

METHOD

Forty 3-month-old male Sprague-Dawley rats were randomly divided into four groups: 30 received surgical collagenase (type II) injections in the right L3-L6 facet joints followed by 8 weeks of treatment with normal saline, CLX or sCT, and the other 10 received sham surgery. Tactile allodynia, changes of cartilage and subchondral bone of the L4-L5 FJs, and serum biomarkers were analyzed for all rats.

RESULTS

Both sCT and CLX ameliorated cartilage lesions, significantly increased aggrecan expression and decreased caspase-3 expression. sCT also decreased the expression of a disintegrin and metalloproteinase with thrombospondin motifs 4 (ADAMTS-4). According to the micro-computed tomography (micro-CT) analysis, sCT significantly improved microarchitecture parameters of subchondral bone and micro-CT score; and inhibited articular process hypertrophy. CLX showed better antihyperalgesic effects than sCT on days 3 and 7 postoperatively despite no statistical differences, whereas sCT possessed better analgesic effects than CLX on days 42 and 56. Besides, the sCT treatment reduced the elevated cartilage oligomeric matrix protein (COMP) concentration in rats injected with collagenase (type II).

CONCLUSIONS

Both sCT and CLX exerted preventive effects on FJ OA caused by collagenase (type II), but sCT showed more protective effects, particularly on maintaining cartilage metabolism, restraining the deterioration of the subchondral bone microarchitecture and tactile allodynia, and reducing serum COMP concentrations.

A dual amylin and calcitonin receptor agonist inhibits pain behavior and reduces cartilage pathology in an osteoarthritis rat model

OBJECTIVES

Pain and disability are the main clinical manifestations of osteoarthritis, for which only symptomatic therapies are available. Hence, there is a need for therapies that can simultaneously alter disease progression and provide pain relief. KBP is a dual amylin- and calcitonin-receptor agonist with antiresorptive and chondroprotective properties. In this study we investigated the effect of KBP in a rat model of osteoarthritis.

METHODS

Medial meniscectomy (MNX) was performed in 39 rats, while 10 underwent sham surgery. Rats were treated with KBP and/or naproxen. Nociception was assessed by mechanical and cold allodynia, weight bearing asymmetry, and burrowing behavior. Blood samples were collected for biomarker measurements, and knees for histology. Cartilage histopathology was evaluated according to the advanced Osteoarthritis Research International (OARSI) score and KBPs in vitro antiresorptive effects were assessed using human osteoclasts cultured on bone.

RESULTS

The MNX animals displayed an increased nociceptive behavior. Treatment with KBP attenuated the MNX-induced osteoarthritis-associated joint pain. The cartilage histopathology was significantly lower in rats treated with KBP than in MNX animals. Bone and cartilage degradation, assessed by CTX-I and CTX-II plasma levels, were decreased in all KBP-treated groups and KBP potently inhibited bone resorption in vitro.

CONCLUSIONS

Our study demonstrates the effectiveness of KBP in ameliorating osteoarthritis-associated joint pain and in protecting the articular cartilage, suggesting KBP as a potential drug candidate for osteoarthritis.

Combining naproxen and a dual amylin and calcitonin receptor agonist improves pain and structural outcomes in the collagen-induced arthritis rat model

Background

Pain is a debilitating symptom of rheumatoid arthritis (RA), caused by joint inflammation and cartilage and bone destruction. Nonsteroidal anti-inflammatory drugs (NSAIDs) are used to treat pain and inflammation in RA, but are not disease-modifying and do not prevent joint destruction when administered alone. KBPs (Key Bioscience peptides) are synthetic peptides based on salmon calcitonin and are expected to inhibit bone resorption and to be chondroprotective. In this study, we investigated if combining a standard of care NSAID (naproxen) with a KBP resulted in improvement in pain scores, as well as disease activity and structural damage in a rat model of RA.

Methods

Collagen-induced arthritis (CIA) was induced in 40 female Lewis rats by immunization with porcine type II collagen; 10 rats were given sham injections. CIA rats were treated with KBP and/or naproxen. Health scores and joint scores were evaluated daily. Mechanical and cold allodynia tests and burrowing tests were used to assess pain-like behaviors. Blood samples were collected for biomarker testing, and paws were collected for histology and microcomputed tomography.

Results

Naproxen monotherapy increased the time until humane endpoints was reached, and improved health score, pain assessments, and trabecular thickness, while KBP monotherapy did not result in improvements. Combination therapy had improved efficacy over naproxen monotherapy; combination therapy resulted in improved health scores, and importantly reduced mechanical and cold allodynia assessment. Furthermore, protection of articular cartilage structure and preservation of bone structure and bone volume were also observed.

Conclusions

This study demonstrates that combining KBP and naproxen may be a relevant therapeutic strategy for RA, resulting in improvements to the overall health, pain, inflammation, and joint structure.

Electronic supplementary material

The online version of this article (10.1186/s13075-019-1819-9) contains supplementary material, which is available to authorized users.

The Activity of Peptides of the Calcitonin Family in Bone

Calcitonin was discovered over 50 yr ago as a new hormone that rapidly lowers circulating calcium levels. This effect is caused by the inhibition of calcium efflux from bone, as calcitonin is a potent inhibitor of bone resorption. Calcitonin has been in clinical use for conditions of accelerated bone turnover, including Paget's disease and osteoporosis; although in recent years, with the development of drugs that are more potent inhibitors of bone resorption, its use has declined. A number of peptides that are structurally similar to calcitonin form the calcitonin family, which currently includes calcitonin gene-related peptides (αCGRP and βCGRP), amylin, adrenomedullin, and intermedin. Apart from being structurally similar, the peptides signal through related receptors and have some overlapping biological activities, although other activities are peptide specific. In bone, in vitro studies and administration of the peptides to animals generally found inhibitory effects on osteoclasts and bone resorption and positive effects on osteoblasts and bone formation. Surprisingly, studies in genetically modified mice have demonstrated that the physiological role of calcitonin appears to be the inhibition of osteoblast activity and bone turnover, whereas amylin inhibits osteoclast activity. The review article focuses on the activities of peptides of the calcitonin family in bone and the challenges in understanding the relationship between the pharmacological effects and the physiological roles of these peptides.

CTX-II and YKL-40 in early diagnosis and treatment evaluation of osteoarthritis

This study investigated the value of C-terminal telopeptides of collagen type II (CTX-II) and YKL-40 in early diagnosis and treatment evaluation of osteoarthritis (OA). A total of 90 patients with OA diagnosed and treated in The First Affiliated Hospital, Guangzhou Medical University from March 2015 to January 2018 were selected as the study group. At the same time, 50 healthy elderly were included as the control group. The study group was divided into three subgroups including group A (29 cases, 500 mg glucosamine sulfate), group B (29 cases, 50 mg diacerein) and group C (32 cases, 500 mg glucosamine sulfate and 50 mg diacerein). Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) was used to assess the severity and treatment of arthritis. Enzyme-linked immunosorbent assay was used to measure the concentration of CTX-II and YKL-40 in serum. WOMAC scores in the study A, B and C groups were significantly higher than those in the control group (P<0.001). Serum CTX-II and YKL-40 concentrations were higher in the study group than in the control group (P<0.001). Sensitivity of serum CTX-II combined with YKL-40 in the diagnosis of OA was 90% and the specificity was 78%. CTX-II and YKL-40 levels in different Kellgren Lawrence (K-L) grades were significantly different (P<0.001), and increased with the increase of K-L grade. Concentrations of serum CTX-II and YKL-40 before treatment in the study group was positively correlated with WOMAC score (P<0.001). At 3, 6 and 9 weeks after the beginning of treatment, serum concentrations of CTX-II and YKL-40 decreased significantly (P<0.001). At 3 weeks of treatment, CTX-II was positively correlated with YKL-40 concentration and WOMAC score (r=0.406, P<0.001; r=0.430, P<0.001); CTX-II was positively correlated with YKL-40 concentration and WOMAC score at 6 weeks of treatment (r=0.350, P<0.001; r=0.358, P<0.001); CTX-II was positively correlated with YKL-40 concentration and WOMAC score at 9 weeks after treatment (r=0.370, P<0.001; r=0.394, P<0.001). Combined detection of serum CTX-II and YKL-40 can improve the sensitivity of early OA diagnosis, and it has an important diagnostic value for early OA patients. Therefore, it can be used as a biological indicator for early OA diagnosis, severity assessment, and evaluation of treatment effects.

Nonclinical and clinical pharmacological characterization of the potent and selective cathepsin K inhibitor MIV-711

BACKGROUND

Cathepsin K is an attractive therapeutic target for diseases in which bone resorption is excessive such as osteoporosis and osteoarthritis (OA). The current paper characterized the pharmacological profile of the potent and selective cathepsin K inhibitor, MIV-711, in vitro and in cynomolgus monkeys, and assessed translation to human based on a single dose clinical study in man.

METHODS

The potency and selectivity of MIV-711 were assessed in vitro using recombinant enzyme assays and differentiated human osteoclasts. MIV-711 was administered to healthy cynomolgus monkeys (3-30 µmol/kg, p.o.). Plasma levels of MIV-711 and the bone resorption biomarker CTX-I were measured after single dose experiments, and urine levels of CTX-I, NTX-I and CTX-II biomarkers were measured after repeat dose experiments. The safety, pharmacokinetics and pharmacodynamics (serum CTX-I) of MIV-711 were assessed in human healthy subjects after single ascending doses from 20 to 600 mg.

RESULTS

MIV-711 was a potent inhibitor of human cathepsin K (K_i: 0.98 nmol/L) with > 1300-fold selectivity towards other human cathepsins. MIV-711 inhibited human osteoclast-mediated bone resorption with an IC₅₀ value of 43 nmol/L. Single oral doses of MIV-711 to monkeys reduced plasma levels of CTX-I in a dose-dependent fashion by up to 57% at trough. The effect on CTX-I was linearly correlated to the plasma exposure of MIV-711, while the efficacy duration outlasted plasma exposure. Repeat oral dosing with MIV-711 also reduced urinary levels of the bone resorption biomarkers CTX-I (by 93%) and NTX-I (by 71%) and the cartilage degradation biomarker CTX-II (by 71%). MIV-711 was safe and well-tolerated when given as single ascending doses to healthy subjects. MIV-711 reduced serum CTX-I levels in a dose-dependent manner by up to 79% at trough. The relationship between MIV-711 exposure and effects on these biomarkers in humans was virtually identical when compared to the corresponding monkey data.

CONCLUSIONS

MIV-711 is a potent and selective cathepsin K inhibitor with dose-dependent effects on biomarkers of bone and cartilage degradation in monkey and human. Taken together, MIV-711 shows promise for the treatment of bone and cartilage related disorders in humans, such as OA. Trial Registration EudraCT number 2011-003024-12, registered on June 22nd 2011.

Salmon Calcitonin Attenuates Degenerative Changes in Cartilage and Subchondral Bone in Lumbar Facet Joint in an Experimental Rat Model

Background

Facet joint degeneration (FJD) is one of the common causes of low back pain (LBP), and estrogen deficiency is one of the triggers for FJD. Calcitonin may possess the potential for treating osteoarthritis, but to date the hormone has not been studied in the treatment of FJD. Therefore, the aim of this study was to investigate the effects of salmon calcitonin (sCT) on FJD induced by estrogen deficiency after ovariectomy (OVX).

Material/Methods

Thirty female Sprague-Dawley rats were randomly assigned to 3 groups: the OVX group received bilateral OVX, the OVX + sCT group received subcutaneous administration of sCT (16 IU/kg/2 days) following bilateral OVX, and the Sham group received sham surgery. All rats were euthanized at 12 weeks post-OVX. Serum COMP level, cartilage degradation, and subchondral bone micro-architecture were evaluated.

Results

sCT relieved cartilage surface lesions, reduced histological score, and significantly increased cartilage thickness. The OVX + sCT group exhibited significantly increased expression of aggrecan, as well as significantly decreased levels of ADAMTS-4, MMP-13, and caspase-3. The results of micro-computed tomography analysis revealed that the OVX + sCT group exhibited higher BMD, BV/TV, and Tb.Th values but a lower Tb.Sp value than that of the OVX group. Serum COMP concentrations were significantly correlated with histological score and cartilage thickness.

Conclusions

sCT can inhibit the progression of FJD in OVX rats, which is attributed to its inhibitory effects on cartilage metabolism imbalance, chondrocyte apoptosis, and subchondral bone remodeling. Serum COMP has diagnostic potential for FJD.

Acute- and late-phase matrix metalloproteinase (MMP)-9 activity is comparable in female and male rats after peripheral nerve injury

BACKGROUND

In the peripheral nerve, pro-inflammatory matrix metalloproteinase (MMP)-9 performs essential functions in the acute response to injury. Whether MMP-9 activity contributes to late-phase injury or whether MMP-9 expression or activity after nerve injury is sexually dimorphic remains unknown.

METHODS

Patterns of MMP-9 expression, activity and excretion were assessed in a model of painful peripheral neuropathy, sciatic nerve chronic constriction injury (CCI), in female and male rats. Real-time Taqman RT-PCR for MMP-9 and its endogenous inhibitor, tissue inhibitor of metalloproteinase-1 (TIMP-1) of nerve samples over a 2-month time course of CCI was followed by gelatin zymography of crude nerve extracts and purified MMP-9 from the extracts using gelatin Sepharose-beads. MMP excretion was determined using protease activity assay of urine in female and male rats with CCI.

RESULTS

The initial upsurge in nerve MMP-9 expression at day 1 post-CCI was superseded more than 100-fold at day 28 post-CCI. The high level of MMP-9 expression in late-phase nerve injury was accompanied by the reduction in TIMP-1 level. The absence of MMP-9 in the normal nerve and the presence of multiple MMP-9 species (the proenzyme, mature enzyme, homodimers, and heterodimers) was observed at day 1 and day 28 post-CCI. The MMP-9 proenzyme and mature enzyme species dominated in the early- and late-phase nerve injury, consistent with the high and low level of TIMP-1 expression, respectively. The elevated nerve MMP-9 levels corresponded to the elevated urinary MMP excretion post-CCI. All of these findings were comparable in female and male rodents.

CONCLUSION

The present study offers the first evidence for the excessive, uninhibited proteolytic MMP-9 activity during late-phase painful peripheral neuropathy and suggests that the pattern of MMP-9 expression, activity, and excretion after peripheral nerve injury is universal in both sexes.

The selective cathepsin K inhibitor MIV-711 attenuates joint pathology in experimental animal models of osteoarthritis

BACKGROUND

MIV-711 is a highly potent and selective cathepsin K inhibitor. The current article summarizes the therapeutic effects of MIV-711 on joint pathology in rabbits subjected to anterior cruciate ligament transection (ACLT), and the prophylactic effects on joint pathology in dogs subjected to partial medial meniscectomy, two surgical models of osteoarthritis (OA).

METHODS

Starting 1 week after surgery, rabbits were dosed daily via oral gavage with either MIV-711 or vehicle (n = 7/group) for 7 weeks. The four treatment groups were: (1) sham + vehicle; (2) ACLT + vehicle; (3) ACLT + MIV-711, 30 µmol/kg and (4) ACLT + MIV-711, 100 µmol/kg. Subchondral bone and articular cartilage structures were assessed by µCT, histomorphometry, and scoring. Dogs subjected to partial medial meniscectomy received either MIV-711 (30 µmol/kg) or vehicle (n = 15/group) via oral gavage once daily, starting 1 day before meniscectomy, for 28 days. Cartilage degradation was assessed at the macroscopic and microscopic levels. The exposures of MIV-711 were assessed in both studies and biomarkers reflecting bone resorption (HP-1 in rabbits, CTX-I in dogs) and cartilage degradation (CTX-II) were measured.

RESULTS

In ACLT rabbits, MIV-711 decreased HP-1 levels by up to 72% (p < 0.001) and CTX-II levels by up to 74% (p < 0.001) compared to ACLT vehicle controls. ACLT surgery significantly reduced the total thickness of the subchondral bone plate and reduced trabecular bone volume in the femur and tibia. These effects were reversed by MIV-711. ACLT resulted in cartilage thickening, which was attenuated by MIV-711. MIV-711 did not affect osteophyte formation or Mankin scores. In dogs, MIV-711 reduced CTX-I and CTX-II levels by 86% (p < 0.001) and 80% (p < 0.001), respectively. Synovial CTX-II levels were reduced by 55-57% (p < 0.001) compared to baseline. MIV-711-treated animals had 25-37% lower macroscopic scores in the femur condyles and 13-33% lower macroscopic scores in the tibial plateaus.

CONCLUSIONS

MIV-711 prevents subchondral bone loss and partially attenuates cartilage pathology in two animal models of OA. These beneficial effects of MIV-711 on joint pathology are observed in conjunction with decreases in bone and cartilage biomarkers that have been shown to be clinically attainable in human. The data support the further development of MIV-711 for the treatment of OA.

Strawberries Improve Pain and Inflammation in Obese Adults with Radiographic Evidence of Knee Osteoarthritis

Osteoarthritis (OA), the most common form of arthritis, is a significant public health burden in U.S. adults. Among its many risk factors, obesity is a key player, causing inflammation, pain, impaired joint function, and reduced quality of life. Dietary polyphenols and other bioactive compounds in berries, curcumin, and tea have shown effects in ameliorating pain and inflammation in OA, but few clinical studies have been reported. The purpose of the present study was to examine the effects of dietary strawberries on pain, markers of inflammation, and quality of life indicators in obese adults with OA of the knee. In a randomized, double-blind cross-over trial, adults with radiographic evidence of knee OA (n = 17; body mass index (BMI): (mean ± SD) 39.1 ± 1.5; age (years): 57 ± 7) were randomized to a reconstituted freeze-dried strawberry beverage (50 g/day) or control beverage daily, each for 12 weeks, separated by a 2-week washout phase (total duration, 26 weeks). Blood draws and assessments of pain and quality of life indicators were conducted using the Visual Analog Scale for Pain (VAS Pain), Measures of Intermittent and Constant Osteoarthritis Pain (ICOAP), and Health Assessment Questionnaire-Disability Index (HAQ-DI) questionnaires, which were completed at baseline and at weeks 12, 14, and 26 of the study. Among the serum biomarkers of inflammation and cartilage degradation, interleukin (IL)-6, IL-1β, and matrix metalloproteinase (MMP)-3 were significantly decreased after strawberry vs. control treatment (all p < 0.05). Strawberry supplementation also significantly reduced constant, intermittent, and total pain as evaluated by the ICOAP questionnaire as well as the HAQ-DI scores (all p < 0.05). No effects of treatment were noted on serum C-reactive protein (CRP), nitrite, glucose, and lipid profiles. Dietary strawberries may have significant analgesic and anti-inflammatory effects in obese adults with established knee OA.

Disease-modifying treatments for osteoarthritis (DMOADs) of the knee and hip: lessons learned from failures and opportunities for the future

Osteoarthritis (OA) is the biggest unmet medical need among the many musculoskeletal conditions and the most common form of arthritis. It is a major cause of disability and impaired quality of life in the elderly. We review several ambitious but failed attempts to develop joint structure-modifying treatments for OA. Insights gleaned from these attempts suggest that these failures arose from unrealistic hypotheses, sub-optimal selection of patient populations or drug dose, and/or inadequate sensitivity of the trial endpoints. The long list of failures has prompted a paradigm shift in OA drug development with redirection of attention to: (1) consideration of the benefits of localized vs systemic pharmacological agents, as indicated by the increasing number of intra-articularly administered compounds entering clinical development; (2) recognition of OA as a complex disease with multiple phenotypes, that may each require somewhat different approaches for optimizing treatment; and (3) trial enhancements based on guidance regarding biomarkers provided by regulatory agencies, such as the Food and Drug Administration (FDA), that could be harnessed to help turn failures into successes.

Intestinal permeation enhancers for oral peptide delivery

Intestinal permeation enhancers (PEs) are one of the most widely tested strategies to improve oral delivery of therapeutic peptides. This article assesses the intestinal permeation enhancement action of over 250 PEs that have been tested in intestinal delivery models. In depth analysis of pre-clinical data is presented for PEs as components of proprietary delivery systems that have progressed to clinical trials. Given the importance of co-presentation of sufficiently high concentrations of PE and peptide at the small intestinal epithelium, there is an emphasis on studies where PEs have been formulated with poorly permeable molecules in solid dosage forms and lipoidal dispersions.

Impact of physical activity and mechanical loading on biomarkers typically used in osteoarthritis assessment: current concepts and knowledge gaps

There is an ongoing need to develop prognostic and diagnostic biomarkers for osteoarthritis (OA). Understanding how biomarkers change in response to physical activity may be vital for understanding if a patient has a joint that is failing to adapt to a given loading stimulus. The purpose of this review is to describe how biomarker changes after joint loading may help detect early OA and determine prognosis. This may help to inform and more specifically target interventions and clinical trials. We conducted a critical review of the relevant literature that was published to January 2016. There is extensive OA biomarker research, specifically basal biomarker concentrations; however, there is limited research surrounding biomarker response to load. Some of this limited research includes the response of minimal biomarkers reflecting bone, synovium, inflammatory, and cartilage responses to load. Biomarker changes occur in bone and cartilage in response to a variety of activities and are influenced by variables such as body weight, load, vibration, and activity time. Biomarker responses to loading tasks may serve as a measure of overall joint health and be predictive of structural changes. Biomarkers adapt to training over time, and this may indicate a need for a gradual return to physical activity after an injury to allow time for joint tissues to adapt to load. Biomarker responses to physical activity may be monitored to determine appropriate loading levels and safety for return to activity.

Meniscal biology in health and disease

The knee is a fascinating yet complex joint. Researchers and clinicians agree that the joint is an organ comprised of highly specialized intrinsic and extrinsic tissues contributing to both health and disease. Key to the function and movement of the knee are the menisci, exquisite fibrocartilage structures that are critical structures for maintaining biological and biomechanical integrity of the joint. The biological/physiological functions of the menisci must be understood at the tissue, cellular and even molecular levels in order to determine clinically relevant methods for assessing it and influencing it. By investigating normal and pathological functions at the basic science level, we can begin to translate data to patients. The objective of this article is to provide an overview of this translational pathway so that progression toward improved diagnostic, preventative, and therapeutic strategies can be effectively pursued. We have thoroughly examined the pathobiological, biomarker, and imaging aspects of meniscus research. This translational approach can be effective toward optimal diagnosis, prevention, and treatment for the millions of patients who suffer from meniscal disorders each year.

Predictive validity of biochemical biomarkers in knee osteoarthritis: data from the FNIH OA Biomarkers Consortium

OBJECTIVE

To investigate a targeted set of biochemical biomarkers as predictors of clinically relevant osteoarthritis (OA) progression.

METHODS

Eighteen biomarkers were measured at baseline, 12 months (M) and 24 M in serum (s) and/or urine (u) of cases (n=194) from the OA initiative cohort with knee OA and radiographic and persistent pain worsening from 24 to 48 M and controls (n=406) not meeting both end point criteria. Primary analyses used multivariable regression models to evaluate the association between biomarkers (baseline and time-integrated concentrations (TICs) over 12 and 24 M, transposed to z values) and case status, adjusted for age, sex, body mass index, race, baseline radiographic joint space width, Kellgren-Lawrence grade, pain and pain medication use. For biomarkers with adjusted p<0.1, the c-statistic (area under the curve (AUC)), net reclassification index and the integrated discrimination improvement index were used to further select for hierarchical multivariable discriminative analysis and to determine the most predictive and parsimonious model.

RESULTS

The 24 M TIC of eight biomarkers significantly predicted case status (ORs per 1 SD change in biomarker): sCTXI 1.28, sHA 1.22, sNTXI 1.25, uC2C-HUSA 1.27, uCTXII, 1.37, uNTXI 1.29, uCTXIα 1.32, uCTXIβ 1.27. 24 M TIC of uCTXII (1.47-1.72) and uC2C-Human Urine Sandwich Assay (HUSA) (1.36-1.50) both predicted individual group status (pain worsening, joint space loss and their combination). The most predictive and parsimonious combinatorial model for case status consisted of 24 M TIC uCTXII, sHA and sNTXI (AUC 0.667 adjusted). Baseline uCTXII and uCTXIα both significantly predicted case status (OR 1.29 and 1.20, respectively).

CONCLUSIONS

Several systemic candidate biomarkers hold promise as predictors of pain and structural worsening of OA.

A reduced graphene oxide-based fluorescence resonance energy transfer sensor for highly sensitive detection of matrix metalloproteinase 2

A novel fluorescence nanoprobe (reduced nano-graphene oxide [nrGO]/fluorescein isothiocyanate-labeled peptide [Pep-FITC]) for ultrasensitive detection of matrix metalloproteinase 2 (MMP2) has been developed by engineering the Pep-FITC comprising the specific MMP2 substrate domain (PLGVR) onto the surface of nrGO particles through non-covalent linkage. The nrGO was obtained by water bathing nano-graphene oxide under 90°C for 4 hours. After mixing the nrGO and Pep-FITC for 30 seconds, the fluorescence from Pep-FITC was almost completely quenched due to the fluorescence resonance energy transfer between fluorescein isothiocyanate (FITC) and nrGO. Upon cleavage of the amide bond between Leu and Gly in the Pep-FITC by protease-MMP2, the FITC bound to nrGO was separated from nrGO surface, disrupting the fluorescence resonance energy transfer process and resulting in fluorescence recovery of FITC. Under optimal conditions, the fluorescence recovery of nrGO/Pep-FITC was found to be directly proportional to the concentration of MMP2 within 0.02–0.1 nM. The detection limit of the nrGO/Pep-FITC was determined to be 3 pM, which is approximately tenfold lower than that of the unreduced carboxylated nano-graphene oxide/Pep-FITC probe.

Wolff's law in action: a mechanism for early knee osteoarthritis

There is growing interest in the role of bone in knee osteoarthritis. Bone is a dynamic organ, tightly regulated by a multitude of homeostatic controls, including genetic and environmental factors. One such key environmental regulator of periarticular bone is mechanical stimulation, which, according to Wolff’s law, is a key determinant of bone properties. Wolff’s law theorizes that repetitive loading of bone will cause adaptive responses enabling the bone to better cope with these loads. Despite being an adaptive response of bone, the remodeling process may inadvertently trigger maladaptive responses in other articular structures. Accumulating evidence at the knee suggests that expanding articular bone surface area is driven by mechanical stimulation and is a strong predictor of articular cartilage loss. Similarly, fractal analysis of bone architecture provides further clues that bone adaptation may have untoward consequences for joint health. This review hypothesizes that adaptations of periarticular bone in response to mechanical stimulation cause maladaptive responses in other articular structures that mediate the development of knee osteoarthritis. A potential disease paradigm to account for such a hypothesis is also proposed, and novel therapeutic targets that may have a bone-modifying effect, and therefore potentially a disease-modifying effect, are also explored.

Emerging drugs for the treatment of knee osteoarthritis

INTRODUCTION

Osteoarthritis (OA) is the most prevailing form of joint disease, with symptoms affecting 10 - 12% of the adult population with a projection of a 50% increase in prevalence in the next two decades. The disease characteristics are defined by articular cartilage damage, low-grade synovial inflammation and hypertrophic bone changes, leading to pain and functional deterioration. To date, available pain treatments are limited in their efficacy and have associated toxicities. No structural disease modification agents have been approved by regulatory agencies for this indication.

AREAS COVERED

We reviewed drugs in Phase II - III for OA pain and joint structure modification. Different aspects of structure modification are divided into targets of inflammatory pathway, cartilage catabolism and anabolism, and subchondral bone remodeling.

EXPERT OPINION

Further insight into the pathophysiology of the disease will allow for development of novel target classes focusing on the link between symptomatology and structural changes. Given the complexity of OA, one single therapy is unlikely to be universally and uniformly effective. Promising therapies are under development, but there are obstacles in the translation of treatment from preclinical models and trial designs need to be cognizant of the complex reasons for previous trial failures.

Lessons learned from the clinical development of oral peptides

The oral delivery of peptides and proteins has been hampered by an array of obstacles. However, several promising novel oral delivery systems have been developed. This paper reviews the most advanced oral formulation technologies, and highlights key lessons and implications from studies undertaken to date with these oral formulations. Special interest is given to oral salmon calcitonin (CT), glucagon-like peptide-1 (GLP-1), insulin, PYY-(3-36), recombinant human parathyroid hormone (rhPTH(1-31)-NH2) and PTH(1-34), by different technologies. The issues addressed include (i) interaction with water, (ii) interaction with food, (iii) diurnal variation, (iv) inter- and intra-subject variability, (v) correlation between efficacy and exposure and (vi) key deliverables of different technologies. These key lessons may aid research in the development of other oral formulations.

Treatment of symptomatic knee osteoarthritis with oral salmon calcitonin: results from two phase 3 trials

PURPOSE

To evaluate the structure-modifying and symptom efficacy, as well as safety and tolerability of oral salmon calcitonin (sCT) formulated with a 5-CNAC carrier (a molecule based on Eligen(®) technology), in osteoarthritis (OA) patients with moderate to severe knee pain and joint structural damage classified as Kellgren and Lawrence (KL)2-3.

METHODS AND DESIGN

This is the combined reporting of two randomized, double-blind, multi-center, placebo-controlled trials (CSMC021C2301 and CSMC021C2302), evaluating the efficacy and safety of oral sCT in patients with painful knee OA with structural manifestations, enrolling 1176 and 1030 patients, respectively. Study subjects were randomized (1:1) to oral sCT 0.8 mg twice daily or placebo (PBO) for 24 months. The primary efficacy objectives were to examine the treatment effect compared to placebo on change over 24 months in joint space width (JSW) in the signal knee measured by X-ray, and to examine the change in pain and function using the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) questionnaire. Other study parameters included patient and physician global assessment, and biochemical markers of bone (CTX-I) and cartilage degradation (CTX-II).

RESULTS

At the 24 month endpoint there was no statistically significant treatment effect on joint space narrowing (JSN) in any of the two studies. In CSMC021C2301 there was a treatment effect on WOMAC (sum of pain, function, stiffness, and total scores) as well as on the biomarkers of bone and joint metabolism, but due to the hierarchical testing procedure the treatment effect was not claimed statistically significant.

CONCLUSIONS

The present formulation of oral sCT did not provide reproducible clinical benefits in patients with symptomatic knee OA (NCT00486434, NCT00704847).

Bone-cartilage interface crosstalk in osteoarthritis: potential pathways and future therapeutic strategies

Currently, osteoarthritis (OA) is considered a disease of the entire joint, which is not simply a process of wear and tear but rather abnormal remodelling and joint failure of an organ. The bone-cartilage interface is therefore a functioning synergistic unit, with a close physical association between subchondral bone and cartilage suggesting the existence of biochemical and molecular crosstalk across the OA interface. The crosstalk at the bone-cartilage interface may be elevated in OA in vivo and in vitro. Increased vascularisation and formation of microcracks associated with abnormal bone remodelling in joints during OA facilitate molecular transport from cartilage to bone and vice versa. Recent reports suggest that several critical signalling pathways and biological factors are key regulators and activate cellular and molecular processes in crosstalk among joint compartments. Therapeutic interventions including angiogenesis inhibitors, agonists/antagonists of molecules and drugs targeting bone remodelling are potential candidates for this interaction. This review summarised the premise for the presence of crosstalk in bone-cartilage interface as well as the current knowledge of the major signalling pathways and molecular interactions that regulate OA progression. A better understanding of crosstalk in bone-cartilage interface may lead to development of more effective strategies for treating OA patients.

Effects of Elaeagnus angustifolia L. supplementation on serum levels of inflammatory cytokines and matrix metalloproteinases in females with knee osteoarthritis

OBJECTIVE

In an attempt to investigate new strategies aimed at reducing inflammation in osteoarthritis, the anti-inflammatory effect of Elaeagnus angustifolia L. as a complementary treatment was evaluated in females with knee osteoarthritis.

METHOD

In this clinical trial, 90 females with mild to moderate osteoarthritis were assigned to two intervention and one placebo groups. In addition to the conventional therapy, the patients in intervention groups received 15g/day of E. angustifolia L. medulla and whole fruit powders respectively for 8 weeks. The levels of tumor necrosis factor-alpha (TNF-α), interleukine-1β (IL-1β), interleukine-10 (IL-10), matrix metalloproteinase-1 (MMP-1) and -13 (MMP-13) were measured with human ELISA kits. Paired t-test and ANOVA were used for statistical analysis.

RESULTS

The statistically significant decrease was observed in the mean levels of serum TNF-α in the medulla (0.004) and whole fruit (0.001) groups after 8 weeks of supplementation. In contrast to the placebo group, there was a significant rise in the mean levels of serum IL-10 in medulla (p-value=0.01) and whole fruit groups (p-value=0.009) at the end of study. The interventions resulted in significant decrease in the mean levels of serum MMP-1 in the medulla (0.001) and whole fruit (0.002) groups. After the interventions, no significant changes were observed in the serum IL-1β and MMP-13 levels.

CONCLUSION

Daily supplementation with E. angustifolia L. in both forms of medulla and whole fruit powders appeared to be effective for decreasing inflammatory cytokines (TNF-α and MMP-1) and enhancing anti-inflammatory cytokines (IL-10).

The future of osteoarthritis therapeutics: emerging biological therapy

Biological therapy is a thriving area of research and development, and is well established for chronic forms of rheumatoid arthritis (RA) and ankylosing spondylitis (AS). However, there is no clinically validated biological therapy for osteoarthritis (OA). Chronic forms of OA are increasingly viewed as an inflammatory disease. OA was largely regarded as a “wear and tear disease”. However, the disease is now believed to involve “low grade” inflammation and the growth of blood vessels and nerves from the subchondral bone into articular cartilage. This realization has focused research effort on the development and evaluation of biological therapy that targets proinflammatory mediators, angiogenic factors and cytokines in articular cartilage, subchondral bone and synovium in chronic forms of OA. This review article provides an overview of emerging biological therapy for OA, and discusses recent molecular targets implicated in angiogenesis and neurogenesis and progress with antibody-based therapy, calcitonin, and kartogenin, the small molecule stimulator of chondrogenesis.

New and emerging treatments for osteoarthritis management: will the dream come true with personalized medicine?

INTRODUCTION

Osteoarthritis (OA) is a dynamic process involving the main tissues of the joint for which a global approach should be considered. No disease-modifying OA drug (DMOAD) has yet been approved. New therapeutic strategies are needed that would be cost effective by reducing the need for pharmacological interventions and surgical management while targeting specific pathways leading to OA. The treatment landscape of OA is about to change based on new agents having shown some structural effects and emerging therapies with DMOAD effects.

AREAS COVERED

In this review based on a Medline (via PubMed) search, promising new and emerging therapies with a potential structural effect (DMOAD) will be discussed including growth factors, platelet-rich plasma, autologous stem cells, bone remodeling modulators, cytokine inhibition, gene therapy, and RNA interference.

EXPERT OPINION

DMOAD development should focus on targeting some phenotypes of OA patients evidenced with sensitive techniques such as magnetic resonance imaging, as a single treatment will unlikely be appropriate for all OA patients. This will allow the development of DMOADs based on personalized medicine. An exciting new era in DMOAD development is within reach, provided future clinical trials are sufficiently powered, systematically designed, use the appropriate evaluation tools, and target the appropriate categories of OA patients.

The coupling of bone and cartilage turnover in osteoarthritis: opportunities for bone antiresorptives and anabolics as potential treatments?

Osteoarthritis (OA) is the most common form of arthritic disease, and a major cause of disability and impaired quality of life in the elderly. OA is a complex disease of the entire joint, affecting bone, cartilage and synovium that thereby presents multiple targets for treatment. This manuscript will summarise emerging observations from cell biology, preclinical and preliminary clinical trials that elucidate interactions between the bone and cartilage components in particular. Bone and cartilage health are tightly associated. Ample evidence has been found for bone changes during progression of OA including, but not limited to, increased turnover in the subchondral bone, undermineralisation of the trabecular structure, osteophyte formation, bone marrow lesions and sclerosis of the subchondral plate. Meanwhile, a range of investigations has shown positive effects on cartilage health when bone resorption is suppressed, or deterioration of the cartilage when resorption is increased. Known bone therapies, namely oestrogens, selective oestrogen receptor modifiers (SERMs), bisphosphonates, strontium ranelate, calcitonin and parathyroid hormone, might prove useful for treating two critical tissue components of the OA joint, the bone and the cartilage. An optimal treatment for OA likely targets at least these two tissue components. The patient subgroups for whom these therapies are most appropriate have yet to be fully defined but would likely include, at a minimum, those with high bone turnover.

Salmon calcitonin use and associated cancer risk

OBJECTIVE

To evaluate the strength of evidence supporting a possible association between salmon calcitonin (SCT) use and cancer incidence.

DATA SOURCES

Searches of MEDLINE/PubMed, MEDLINE/OVID, and EMBASE (January 1973 to September 2013) were performed using the key search terms salmon calcitonin, humans, nasal calcitonin, and (for EMBASE only) randomized controlled trial. We also performed a manual review of data reviewed by the US Food and Drug Administration (FDA) committee in 2013.

STUDY SELECTION AND DATA EXTRACTION

All articles identified from the data sources were evaluated and all information deemed relevant was included for this review.

DATA SYNTHESIS

Intranasal and injectable SCT are FDA-approved for the treatment of postmenopausal osteoporosis. After a safety signal suggested a possible link between SCT use and prostate cancer, the European Medicines Agency and FDA regulatory agencies conducted analyses of SCT randomized controlled trial data to assess cancer-related adverse events and to readdress the approval status of SCT. Eighteen studies were found that compared nasal or oral SCT and placebo. In 15 of the 18 studies, the percentage of malignancy was greater in the SCT arm. The studies varied in quality, outcomes, and length. Most of the studies had poor-quality methods to assess new cancer cases.

CONCLUSIONS

Current evidence may suggest an association between SCT use and cancer incidence based on studies with poor-quality cancer assessment methods. However, considering the lack of demonstrated efficacy of SCT to reduce fractures, clinicians should consider discontinuing its use for osteoporosis treatment regardless of the FDA's final approval decision.

Mucoadhesive intestinal devices for oral delivery of salmon calcitonin

One of the major challenges faced by therapeutic polypeptides remains their invasive route of delivery. Oral administration offers a potential alternative to injections; however, this route cannot be currently used for peptides due to their limited stability in the stomach and poor permeation across the intestine. Here, we report mucoadhesive devices for oral delivery that are inspired by the design of transdermal patches and demonstrate their capabilities in vivo for salmon calcitonin (sCT). The mucoadhesive devices were prepared by compressing a polymeric matrix containing carbopol, pectin and sodium carboxymethylcellulose (1:1:2), and were coated on all sides but one with an impermeable and flexible ethyl cellulose (EC) backing layer. Devices were tested for in vitro dissolution, mucoadhesion to intestinal mucosa, enhancement of drug absorption in vitro (Caco-2 monolayer transport) and in vivo in rats. Devices showed steady drug release with ≈75% cumulative drug released in 5h. Devices also demonstrated strong mucoadhesion to porcine small intestine to withstand forces up to 100 times their own weight. sCT-loaded mucoadhesive devices exhibited delivery of sCT across Caco-2 monolayers and across the intestinal epithelium in vivo in rats. A ≈52-fold (pharmacokinetic) and ≈44-fold (pharmacological) enhancement of oral bioavailability was observed with mucoadhesive devices when compared to direct intestinal injections. Oral delivery of devices in enteric coated capsules resulted in significant bioavailability enhancement.

An OA phenotype may obtain major benefit from bone-acting agents

BACKGROUND

Osteoarthritis (OA) joints display relevant microstructure alterations associated to an increase in remodeling at subchondral bone, which supports its crucial role in OA pathogenesis. Despite this, the treatment of knee OA patients with antiresorptive drugs has given discordant results, suggesting the existence of a particular patient subset with good response to halting high subchondral remodeling.

OBJECTIVE

To identify an OA phenotype that may obtain major benefit from therapy with bone-acting agents.

METHODS

A systematic review of the literature was performed by searching the Medline and PubMed databases from 1990 to April 2013 using the following keywords: subchondral bone, articular cartilage, and osteoarthritis in various combinations with bone agents, bone mineral density, and scintigraphy.

RESULTS

Early animal and human studies provided the rationale for the beneficial use of bone agents on OA cartilage damage. Several bone-acting agents have reduced low back pain and likely spondylosis progression. Recently, strontium ranelate has been reported to exert both structural and clinical benefits in knee OA patients with radiological progression. However, other antiresorptives have shown divergent results. Human studies suggest that these contradictory results may be due to the lack of well-defined OA phenotypes and an accurate methodology to recruit and follow up these patients.

CONCLUSIONS

A particular subset of postmenopausal patients with high remodeling and/or low subchondral bone density may benefit from the treatment with bone-acting agents hindering OA progression. This OA population could be identified with the simultaneous use of subchondral bone dual-energy X-ray absorptiometry and scintigraphy.

Osteoarthritis and osteoporosis: what is the overlap?

Osteoarthritis (OA) and osteoporosis (OP) are highly prevalent health problems, associated with considerable morbidity. In the past, attention was focused on a supposed inverse relationship between OA and OP, since both disorders usually affect the elderly, but were regarded to rarely coexist in a single person. However, recent studies have revealed several factors which contribute to the pathogenesis of both disorders. These insights might contribute to the development of shared new treatment options in the near future. Increased subchondral bone loss is a characteristic feature of OP and the early stage of OA, and this finding is the rationale for studies on the effect of anti-osteoporotic drugs in OA. In addition, inflammation and unfavourable body composition have been recognized as contributing factors for both disorders. Underweight is a risk factor for OP, while obesity stimulates the development of OA, by mechanical overloading of weight-bearing joints but also by supposed unfavourable effects of adipokines.

Nutraceuticals for older people: facts, fictions and gaps in knowledge

In the last decades nutraceuticals have entered the health market as an easy and attractive means of preventing diseases. These products are of interest for an increasingly health-concerned society and may be especially relevant for preventing or delaying a number of age-related diseases, i.e. arthritis, cancer, metabolic and cardiovascular diseases, osteoporosis, cataracts, brain disorders, etc. Nutraceuticals are marketed in a variety of forms, composition and potential applications which have made their definition ambiguous and their use uncontrolled and poorly funded. Although epidemiological, animal and in vitro studies have given evidence of the potential benefits of some of these nutraceuticals or of their components, definitive proof of their effects in appropriate human clinical trials is still lacking in most cases, more critically among people above 65 years of age. We cover the well-established nutraceuticals (polyvitamins, omega-3 fatty acids, etc.) and will focus on many other 'novel' commercial nutraceuticals where the scientific evidence is more limited (food extracts, polyphenols, carotenoids, etc.). Solid scientific evidence has been reported only for a few nutraceuticals, which have some health claims approved by the European Food Safety Authority (EFSA). Further well-designed trials are needed to improve the current knowledge on the health benefits of nutraceuticals in the elderly. Overall, there are some facts, a lot of fiction and many gaps in the knowledge of nutraceutical benefits.

New horizons in osteoarthritis

Osteoarthritis (OA) is the most common type of arthritis worldwide and rapidly increasing with ageing populations. It is a major source of pain and disability for individuals and economic burden for health economies. Modern imaging, in particular magnetic resonance imaging (MRI), has helped us to understand that OA is a dynamic remodelling process involving all the structures within the joint. Inflammation is common in OA, with a high prevalence of synovitis seen on imaging, and this has been associated with joint pain. MRI detected changes within the subchondral bone are also common and associated with pain and structural progression. Targeting individual pathologies may offer potential new therapeutic options for OA; this is particularly important given the current treatments are often limited by side effects or lack of efficacy. New approaches to understanding the pathology and pain pathways in OA offer hope of novel analgesic options, for example, monoclonal antibodies against nerve growth factor and centrally acting drugs such as duloxetine, tapentadol and bradykinin receptor antagonists have all recently undergone trials in OA. While treatment for OA has until now relied on symptom management, for the first time, recent trials suggest that structure modification may be possible by treating the subchondral bone.

The potential protective effects of calcitonin involved in coordinating chondrocyte response, extracellular matrix, and subchondral trabecular bone in experimental osteoarthritis

Previous reports indicate a potential role for calcitonin (CT) in the treatment of osteoarthritis (OA). To evaluate this potential therapeutic role, we investigated the effect of CT pretreatment on the activation of mitogen-activated protein kinase (MAPK) signaling and the expression of matrix metalloproteinase-13 (MMP-13) in interleukin-1β (IL-1β)-induced chondrocytes, and further assessed its protective effect in a rat model of anterior cruciate ligament transection (ACLT), using sham-operated and saline-treated controls. Using western blotting in vitro, we found that CT pretreatment inhibited the IL-1β-induced phosphorylation of 38,000-dalton protein (p38) and extracellular regulated protein 1/2 (ERK1/2) and reduced the expression of MMP-13 protein. For the in vivo experiment, 30 male rats were randomly divided into three groups of 10, subjected to bilateral ACLT or sham surgery, and then treated for 12 weeks with subcutaneous injections of CT or normal saline. Histological observations showed that CT treatment reduced the severity of the cartilage lesions stemming from the ACLT surgery and provided a lower Mankin score when compared with that determined for rats in the saline-treated ACLT group. Immunohistochemical staining revealed that CT treatment increased type II collagen expression and decreased MMP-3 and a disintegrin and metalloproteinase with thrombospondin motifs-4 (ADAMTS-4) expression when compared with the saline-treated group. Subchondral bone analysis indicated that CT treatment inhibited the reduction in bone mineral density observed in the saline-treated ACLT group and reduced the ACLT-induced destruction to the subchondral trabecular microstructure. Our data demonstrate that CT induces its protective effects by reducing the chondrocyte response to inflammatory stimuli, cartilage extracellular matrix degradation, and subchondral trabecular microstructure damages brought on by OA.

Disease-modifying osteoarthritis drugs: in vitro and in vivo data on the development of DMOADs under investigation

INTRODUCTION

Osteoarthritis is a disabling affliction, and disease-modifying osteoarthritis drugs (DMOADs) would be highly desirable adjuncts to symptomatic relief as they may delay the disease process.

AREAS COVERED

This study is a comprehensive review of the recent literature on the efficacy of DMOADs in the treatment of OA. In vitro and in vivo evidence was collected using MEDLINE® (1950 to November 2012) and EMBASE (1980 to November 2012) databases. Several drugs have demonstrated DMOAD effects in OA. They can be divided into three groups based on their predominant mode of action: those targeting cartilage, inflammatory pathways and subchondral bone. OARSI guidelines recommend glucosamine and chondroitin sulphates and diacerein as DMOADS, and NICE will recommend glucosamine sulphate in the next update of guidelines. Exploration of improved outcome measures and identification of subgroups of patients most likely to benefit from different DMOADs are likely to be the most important areas of development over the coming years.

EXPERT OPINION

It is expected that a wider range of prospective clinical studies will be embarked upon in the coming years. Trials including MRI as well as joint space narrowing (JSN) should be designed in a systematic manner, powered with sufficient numbers to demonstrate clinical benefit at different stages of disease.

An intra-articular salmon calcitonin-based nanocomplex reduces experimental inflammatory arthritis

Prolonged inappropriate inflammatory responses contribute to the pathogenesis of rheumatoid arthritis (RA) and to aspects of osteoarthritis (OA). The orphan nuclear receptor, NR4A2, is a key regulator and potential biomarker for inflammation and represents a potentially valuable therapeutic target. Both salmon calcitonin (sCT) and hyaluronic acid (HA) attenuated activated mRNA expression of NR4A1, NR4A2, NR4A3, and matrix metalloproteinases (MMPs) 1, 3 and 13 in three human cell lines: SW1353 chondrocytes, U937 and THP-1 monocytes. Ad-mixtures of sCT and HA further down-regulated expression of NR4A2 compared to either agent alone at specific concentrations, hence the rationale for their formulation in nanocomplexes (NPs) using chitosan. The sCT released from NP stimulated cAMP production in human T47D breast cancer cells expressing sCT receptors. When NP were injected by the intra-articular (I.A.) route to the mouse knee during on-going inflammatory arthritis of the K/BxN serum transfer model, joint inflammation was reduced together with NR4A2 expression, and local bone architecture was preserved. These data highlight remarkable anti-inflammatory effects of sCT and HA at the level of reducing NR4A2 mRNA expression in vitro. Combining them in NP elicits anti-arthritic effects in vivo following I.A. delivery.

Colonic absorption of salmon calcitonin using tetradecyl maltoside (TDM) as a permeation enhancer

Calcitonin is used as a second line treatment of postmenopausal osteoporosis, but widespread acceptance is somewhat limited by subcutaneous and intranasal routes of delivery. This study attempted to enable intestinal sCT absorption in rats using the mild surfactant, tetradecyl maltoside (TDM) as an intestinal permeation enhancer. Human Caco-2 and HT29-MTX-E12 mucus-covered intestinal epithelial monolayers were used for permeation studies. Rat in situ intestinal instillation studies were conducted to evaluate the absorption of sCT with and without 0.1 w/v% TDM in jejunum, ileum and colon. TDM significantly enhanced sCT permeation across intestinal epithelial monolayers, most likely due to combined paracellular and transcellular actions. In situ, TDM caused an increased absolute bioavailability of sCT in rat colon from 1.0% to 4.6%, whereas no enhancement increase was observed in ileal and jejunal instillations. Histological analysis suggested mild perturbation of colonic epithelia in segments instilled with sCT and TDM. These data suggest that the membrane composition of the colon is different to the small intestine and that it is more amenable to permeation enhancement. Thus, formulations designed to release payload in the colon could be advantageous for systemic delivery of poorly permeable molecules.

Impact of treatments for osteoporosis on cartilage biomarkers in humans

The rationale to target bone for treating osteoarthritis (OA) relies on the known cross-talk between subchondral bone and cartilage and the demonstration that subchondral bone resorption occurs at an early stage in the development of OA. Therefore, the possible OA disease-modifying effects of bone antiresorptive agents are of interest. This paper aims to review the published data on the effect of estrogens, selective estrogen receptor modulators, calcitonin, strontium ranelate, and bisphosphonates on cartilage biomarkers levels used as surrogate endpoints in clinical trials. Except for findings for tibolone, most observations indicated that these antiresorptive therapies decreased the urinary levels of CTX-II, a biomarker of type II collagen degradation. These data, which should be cautiously interpreted, suggest that these drugs might favorably affect cartilage homeostasis.

Inhalation therapy of calcitonin relieves osteoarthritis of the knee

This study was conducted to determine if nasal salmon calcitonin has additional beneficial effects on clinical symptoms, serum NO, IL-1β, matrix metalloproteinase 3, urinary C-terminal telopeptide type II collagen (CTX-II) levels and MRI findings in knee osteoarthritis (OA) when used concomitantly with exercise therapy. Fifty female patients with knee OA were randomized into two groups. The first group (n = 30) received 200 IU/day nasal salmon calcitonin and a home exercise program; the second group (n = 20) received a home exercise program for 6 months. Compared with baseline,while significant improvements were observed in visual analogue scale (VAS), WOMAC pain, physical function scores, 20-m walking time (P < 0.001) and WOMAC stiffness score (P = 0.041) in the first group, walking and resting VAS, and WOMAC physical function scores were improved (P = 0.029) in the second group after treatment. Significantly increased levels of serum NO and urinary CTX-II (P < 0.001) and significant improvements in the area of medial femoral condyle (P < 0.05) were noted only in the first group. There were significant differences in VAS activation values (P = 0.032) and NO levels (P < 0.001) in the favor of the first group. In conclusion, nasal salmon calcitonin may have possible chondroprotective effects besides its known effects on symptoms in patients with knee OA.

Bone health and associated metabolic complications in neuromuscular diseases

This article reviews the recent literature regarding bone health as it relates to the patient living with neuromuscular disease (NMD). Studies defining the scope of bone-related disease in NMD are scant. The available evidence is discussed, focusing on abnormal calcium metabolism, increased fracture risk, and the prevalence of both scoliosis and hypovitaminosis D in Duchenne muscular dystrophy, amyotrophic lateral sclerosis, and spinal muscular atrophy. Future directions are discussed, including the urgent need for studies both to determine the nature and extent of poor bone health, and to evaluate the therapeutic effect of available osteoporosis treatments in patients with NMD.

The pathogenesis of osteoarthritis involves bone, cartilage and synovial inflammation: may estrogen be a magic bullet?

The female predominance of polyarticular osteoarthritis (OA), and in particular the marked increase of OA in women after the menopause points to a likely involvement of female sex hormones in the maintenance of cartilage homeostasis. This perception has inspired many research groups to investigate the role of estrogens in the modulation of cartilage homeostasis with the ultimate aim to clarify whether estrogen replacement therapy (ERT) could provide benefits in preventing the rapid rise in the prevalence of OA in postmenopausal women. The effects of ERT and selective estrogen-receptor modulators on the joint in various experimental models have been investigated. Clinically, the effects of estrogens have been evaluated by post hoc analysis in clinical trials using biochemical markers of cartilage and bone degradation. Lastly, the Women's Health Initiative trial (WHI) investigated the effects of estrogens on the joint and joint replacements. Even though the exact mode of action still needs to be elucidated, the effect involves both direct and indirect mechanisms on the whole joint pathophysiology. Several animal models have demonstrated structural benefits of estrogens, as well as significant effects on joint inflammation. This is in complete alignment with clinical data using biochemical markers of joint degradation which demonstrated approximately 50% inhibition of cartilage destruction. These finding were recently validated in WHI, where women taking estrogens had significantly less joint replacement. In conclusion, the pleiotropic effect of estrogens on several different tissues may match the complicated aetiology of OA in some important aspects.

Oral calcitonin

Calcitonin is a hormone secreted by the C-cells of the thyroid gland in response to elevations of the plasma calcium level. It reduces bone resorption by inhibiting mature active osteoclasts and increases renal calcium excretion. It is used in the management of postmenopausal osteoporosis, Paget’s disease of bone, and malignancy-associated hypercalcemia. Synthetic and recombinant calcitonin preparations are available; both have similar pharmacokinetic and pharmacodynamic profiles. As calcitonin is a peptide, the traditional method of administration has been parenteral or intranasal. This hinders its clinical use: adherence with therapy is notoriously low, and withdrawal from clinical trials has been problematic. An oral formulation would be more attractive, practical, and convenient to patients. In addition to its effect on active osteoclasts and renal tubules, calcitonin has an analgesic action, possibly mediated through β-endorphins and the central modulation of pain perception. It also exerts a protective action on cartilage and may be useful in the management of osteoarthritis and possibly rheumatoid arthritis. Oral formulations of calcitonin have been developed using different techniques. The most studied involves drug-delivery carriers such as Eligen^® 8-(N-2hydroxy-5-chloro-benzoyl)-amino-caprylic acid (5-CNAC) (Emisphere Technologies, Cedar Knolls, NJ). Several factors affect the bioavailability and efficacy of orally administered calcitonin, including amount of water used to take the tablet, time of day the tablet is taken, and proximity to intake of a meal. Preliminary results looked promising. Unfortunately, in two Phase III studies, oral calcitonin (0.8 mg with 200 mg 5-CNAC, once a day for postmenopausal osteoporosis and twice a day for osteoarthritis) failed to meet key end points, and in December 2011, Novartis Pharma AG announced that it would not pursue further clinical development of oral calcitonin for postmenopausal osteoporosis or osteoarthritis. A unique feature of calcitonin is that it is able to uncouple bone turnover, reducing bone resorption without affecting bone formation and therefore increasing bone mass and improving bone quality. This effect, however, may be dose-dependent, with higher doses inhibiting both resorption and formation. Because so many factors affect the pharmacokinetics and pharmacodynamics of calcitonin, especially orally administered calcitonin, much work remains to be done to explore the full pharmacologic spectrum and potential of calcitonin and determine the optimum dose and timing of administration, as well as water and food intake.