Bisphosphonates beyond their anti-osteoclastic properties

Bone Turnover Markers and Wnt Signaling Modulators in Early Complex Regional Pain Syndrome. A Pre-specified Observational Study

To explore serum levels of some bone turnover markers and the involvement of the Wnt signaling in CRPS-1. Query ID="Q1" Text="Please check and confirm whether the edit made to the article title is in order." We conducted an observational study on patients with early CRPS-1 recruited before any treatment. Clinical measures were assessed together with biochemical evaluation. Values of sclerostin, DKK1, CTX-I, and P1NP were compared with sex-age-matched healthy controls (HCs). We enrolled 34 patients diagnosed with CRPS-1 (mean age 59.3 ± 10.6 years, Male/Female 10/24), median disease duration = 2 weeks (IQR 1-5); median VAS score = 76 (IQR 68-80). Foot localization was slightly more frequent than hand localization (18/16). No statistically significant difference was found between CRPS-1 patients and HCs for CTX-I (0.3 ± 0.1 ng/ml vs 0.3 ± 0.1, p = 0.140), while mean serum values of P1NP were significantly higher in CRPS-1 patients compared to HCs (70.0 ± 38.8 ng/ml vs 50.1 ± 13.6, p = 0.005). Mean levels of sclerostin and DKK1 were lower in CRPS-1 patients vs HCs (sclerostin 28.4 ± 10.8 pmol/l vs 34.1 ± 11.6, p = 0.004; DKK1 12.9 ± 10.8 pmol/l vs 24.1 ± 11.9, p = 0.001). No statistically significant difference was found for all biochemical assessments in a subgroup of fracture-induced CRPS-1. No statistically significant differences were observed according to disease localization, disease duration, presence of hyperalgesia, allodynia, sudomotor alterations, and mild or moderate/severe swelling. No significant correlation emerged between sclerostin, DKK1 levels, baseline VAS score, or McGill Pain Questionnaire score. Bone involvement in early CRPS-1 does not seem to rely on increased osteoclast activity. Conversely, a serum marker of bone formation resulted increased. Both Sclerostin and DKK1 showed decreased values, probably suggesting a widespread osteocyte loss of function.Trial registration number: Eudract Number: 2014-001156-28.

Long-term efficacy and safety of neridronate treatment in patients with complex regional pain syndrome type 1: a pre-specified, open-label, extension study

Background

No data on the permanent and curative effect of bisphosphonate treatment in patients with complex regional pain syndrome type-1 (CRPS-1) are currently available. The aim of this pre-specified, open-label, observational study was to evaluate the long-term efficacy and safety of neridronate treatment.

Design

A pre-specified, open-label, extension study.

Methods

Patients treated with intramuscular (IM) placebo in the double-blind phase of the study were assigned to 100 mg intravenous (IV) neridronate treatment administered 4 times over 10 days. These patients, together with those previously treated with 400 mg IM neridronate, were followed for 1 year. Efficacy was assessed using a visual analogue scale (VAS) pain score. Changes in clinical signs and symptoms, quality of life (QoL) using the Short Form Health Survey (SF-36), and the McGill Pain Questionnaire were also assessed.

Results

Benefits on pain, clinical and functional measures were maintained and further improved over 12 months in most patients treated with neridronate administered either IM or IV. In IM-treated patients, the percentage of those defined as responders (VAS score reduction ≥ 50%) progressively increased up to day 360 to 32 of 35 patients (91.4%). Among the 27 patients referred to as responders at the end of the double-blind phase, 26 reported the same result at day 360 (96.3%). In IV-treated patients, a responder rate of 88% (22 out 25) was found at day 360 (p = 0.66 between groups). Consistent improvements were also observed for all clinical signs and functional questionnaire. No drug-related adverse events were reported during the study.

Conclusion

In patients with acute CRPS-1, the benefit in pain, clinical, and functional measures observed a few weeks after neridronate treatment administered either IM or IV is maintained and further improved over 12 months. Parenteral neridronate induces permanent disease remission preventing chronic pain and motor dysfunction.

Trial registration

EU Clinical Trials Register (EudraCT Number): 2014-001156-28.

In vitro evidence for the involvement of H2S pathway in the effect of clodronate during inflammatory response

Clodronate is a bisphosphonate agent commonly used as anti-osteoporotic drug. Throughout its use, additional anti-inflammatory and analgesic properties have been reported, although the benefits described in the literature could not solely relate to their inhibition of bone resorption. Thus, the purpose of our in vitro study is to investigate whether there are underlying mechanisms explaining the anti-inflammatory effect of clodronate and possibly involving hydrogen sulphide (H₂S). Immortalised fibroblast-like synoviocyte cells (K4IM) were cultured and treated with clodronate in presence of TNF-α. Clodronate significantly modulated iNOS expression elicited by TNF-α. Inflammatory markers induced by TNF-α, including IL-1, IL-6, MCP-1 and RANTES, were also suppressed following administration of clodronate. Furthermore, the reduction in enzymatic biosynthesis of CSE-derived H₂S, together with the reduction in CSE expression associated with TNF-α treatment, was reverted by clodronate, thus rescuing endogenous H₂S pathway activity. Clodronate displays antinflammatory properties through the modulation of H₂S pathway and cytokines levels, thus assuring the control of the inflammatory state. Although further investigation is needed to stress out how clodronate exerts its control on H₂S pathway, here we showed for the first the involvement of H₂S in the additive beneficial effects observed following clodronate therapy.

Intramuscular neridronate for the treatment of complex regional pain syndrome type 1: a randomized, double-blind, placebo-controlled study

Background:

Complex regional pain syndrome type-1 (CRPS-1) is a severely disabling painful disease challenging to treat. This multicenter, randomized, double-blind placebo-controlled trial examined the efficacy of intramuscular (i.m.) neridronate in CRPS-1 patients.

Methods:

A total of 78 patients diagnosed with CRPS-1 (aged 59.5 ± 10.3, 66.7% female) were randomly assigned to 25 mg (i.m.) neridronate (N = 41) given once daily for 16 consecutive days or placebo control (N = 37). Efficacy was assessed after 30 days using a visual analogue scale (VAS) pain score and the number of patients achieving ⩾50% reduction in VAS score. Change in clinical signs and symptoms, quality of life (QoL) using Short Form Health Survey (SF-36) and the McGill Pain Questionnaire were also assessed.

Results:

After 30 days, VAS score decreased significantly to a greater extent in neridronate-treated patients versus placebo (31.9 ± 23.3 mm versus 52.3 ± 27.8 mm, p = 0.0003). Furthermore, the proportion of patients achieving a VAS reduction of ⩾50% was greater in the neridronate group (65.9% versus 29.7%, p = 0.0017). Clinical signs and symptoms were improved significantly in the neridronate group versus placebo for edema (72.5% versus 79.9%, p = 0.03), pain during motion (70% versus 83.3%, p = 0.0009), allodynia (20% versus 63.3%, p = 0.0004), and hyperalgesia (20% versus 56.7%, p = 0.0023). Whereas no difference was observed for QoL measures using the SF-36 questionnaire, three of the four pain variables using the McGill Pain Questionnaire improved significantly in the neridronate group. No serious drug-related adverse events were reported during the study.

Conclusion:

In patients with acute CRPS-1, i.m. injections of 25 mg neridronate were associated with clinically relevant benefit compared with placebo controls.

Trial registration:

EU Clinical Trials Register: https://www.clinicaltrialsregister.eu/ctr-search/search?query=2014-001156-28

Complex regional pain syndrome and bone marrow oedema syndrome: family ties potentially closer than expected

Complex regional pain syndrome (CRPS) and bone marrow edema syndrome (BMES) are two rare conditions that are still being discussed. They are generally considered as two distinct entities, yet they share similarities such as a homogeneous bone marrow edema is also often found in the early phase of CRPS. We present the case of a 41-year-old man with CRPS after a foot fracture followed by the development of painful BMES of the ipsilateral knee and hip a few weeks later. The search for another pathology was negative. After pamidronate infusions, the evolution was spectacular: the disappearance of hip pain at 1 month and more than 50% reduction in knee and foot pain at 2 months. At final follow-up (1 year), the patient was asymptomatic. This case reinforces the idea of a possible link between CRPS and BMES probably through similar trabecular bone involvement. Imaging remains useful in diagnosis of CRPS.

Synthesis, antiinflammatory activity, and molecular docking studies of bisphosphonic esters as potential MMP-8 and MMP-9 inhibitors

Bisphosphonic acids (or bisphosphonates) have been successfully used in the clinic treatment of bone diseases for over decades. Additionally, the antiinflammatory activity of these compounds has been gaining attention. In our previous work, we synthesized and in vivo evaluated the bisphosphonic esters 1 and 2, finding a moderate edema inhibition upon oral and topical administration on BALB/c mice. Thus, in this work, the bioisosteric replacement of an amide functional group for an ester afforded the new bisphosphonates 3-6, which had a moderate oral edema inhibition (25 mg/kg dose) and a significant topical antiinflammatory activity (2 mg/ear) on BALB/c mice, with 6 being the most active hit (55.9% edema inhibition), comparable to the positive control (55.5% edema inhibition) on a TPA topical model. Next, to assess the acute toxicity of the synthesized derivatives, test animals were administered with 50-100 mg/kg of 3-6, respectively, by an oral route, and after 14 days, neither lethality nor a significative weight loss were observed. Finally, a structure-activity relationship (SAR) and a molecular docking analysis of 3-6 helped us to explain the trend observed in biological tests. Considering all these aspects, we propose the inhibition of MMP-8 and MMP-9 as a possible action mechanism of the synthesized derivatives.

Pharmacology of bisphosphonates in pain

The treatment of pain, in particular, chronic pain, remains a clinical challenge. This is particularly true for pain associated with severe or rare conditions, such as bone cancer pain, vulvodynia, or complex regional pain syndrome. Over the recent years, there is an increasing interest in the potential of bisphosphonates in the treatment of pain, although there are few papers describing antinociceptive and anti-hypersensitizing effects of bisphosphonates in various animal models of pain. There is also increasing evidence for clinical efficacy of bisphosphonates in chronic pain states, although the number of well-controlled studies is still limited. However, the mechanisms underlying the analgesic effects of bisphosphonates are still largely elusive. This review provides an overview of preclinical and clinical studies of bisphosphonates in pain and discusses various pharmacological mechanisms that have been postulated to explain their analgesic effects. LINKED ARTICLES: This article is part of a themed issue on The molecular pharmacology of bone and cancer-related bone diseases. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v178.9/issuetoc.

Bone microstructure is significantly altered in CRPS-affected distal tibiae as detected by HR-pQCT: a retrospective cross-sectional study

In the course of complex regional pain syndrome (CRPS), local osteopenia in the subchondral/subcortical areas of the affected limb represents a central manifestation. Mechanistic aspects of CRPS-associated pathologies remain unclear, and knowledge about bone morphology in CRPS-affected areas is rare. The aim of this study was to assess trabecular and cortical bone microstructure in patients with CRPS of the distal tibiae. We retrospectively analysed 14 women diagnosed with unilateral CRPS type I of the lower limb whose affected and unaffected distal tibiae were examined by high-resolution peripheral quantitative computed tomography (HR-pQCT). Laboratory tests included serum levels of calcium, phosphate, 25-hydroxyvitamin D, bone alkaline phosphatase, parathyroid hormone, osteocalcin and urinary levels of deoxypyridinoline (DPD). Bone mineral density was measured by dual-energy X-ray absorptiometry (DXA) at the lumbar spine and both proximal femurs. Average urinary DPD levels, a biochemical marker of bone resorption, were elevated in the examined patient cohort (7.1 ± 1.9 nmol/mmol, reference 3.0-7.0 nmol/mmol). According to HR-pQCT, CRPS-affected distal tibiae showed significantly lower values of cortical BMD and cortical thickness compared to the unaffected contralateral side. Also, bone volume relative to total volume was significantly lower. Trabecular number and trabecular thickness tended to be lower in the affected tibiae. CRPS is associated with significant alterations in bone microstructure of the affected tibiae. Increased bone resorption seems to play a crucial role within a multifactorial process of CRPS-mediated bone atrophy. HR-pQCT could possibly serve as a diagnostic tool in specific CRPS therapy.

Bisphosphonates in the treatment of complex regional pain syndrome: is bone the main player at early stage of the disease?

Complex Regional Pain Syndrome type 1 (CRPS-1) is a disabling painful disease whose hallmark is pain disproportionate to inciting event. CRPS is also characterized by symptoms and signs, such as vasomotor, sudomotor, trophic and motor changes. Therapeutic approach of CRPS-1 still remains a challenge for clinicians treating a disease with potential heavy consequences on patient prognosis. In the past years, the treatment with bisphosphonates (BPs) has gained some success as confirmed by the results of a number of meta-analyses. The aim of this paper is to point out the pivotal role of bone in CRPS pathogenesis. The efficacy of BPs is likely to be related to bone tissue involvement in the early pathophysiological steps of the disease, as demonstrated by evidences highlighting the central role of bone in the initial phases. Bone can become a source of inflammatory cytokines when triggered by a direct injury. Moreover, peptidergic fibers that innervate both mineralized bone and bone marrow can play a role in triggering or maintaining the microvascular disturbance at bone level. Indeed, bone involvement is consistent with the mineralization disturbance as well as the results of instrumental investigations (e.g., MRI, bone scan). In this regard, an intriguing issue relies on the excellent therapeutic response to BPs treatment of other diseases (e.g., Transient Osteoporosis of the Hip and Regional Migratory Osteoporosis) that share with CRPS-1 some clinical and instrumental features.

Evaluation of bone microstructure in CRPS-affected upper limbs by HR-pQCT

INTRODUCTION

Complex regional pain syndrome (CRPS) is a major complication after trauma, surgery, and/or immobilization of an extremity. The disease often starts with clinical signs of local inflammation and develops into a prolonged phase that is characterized by trophic changes and local osteoporosis and sometimes results in functional impairment of the affected limb. While the pathophysiology of CRPS remains poorly understood, increased local bone resorption plays an undisputed pivotal role. The aim of this retrospective clinical study was to assess the bone microstructure in patients with CRPS.

METHODS

Patients with CRPS type I of the upper limb whose affected and unaffected distal radii were analyzed by high-resolution peripheral quantitative computed tomography (HR-pQCT) were identified retrospectively. The osteology laboratory data and dual-energy X-ray absorptiometry (DXA) images of the left femoral neck and lumbar spine, which were obtained on the same day as HR-pQCT, were extracted from the medical records.

RESULTS

Five patients were identified. The CRPS-affected upper limbs had significantly lower trabecular numbers and higher trabecular thicknesses than the unaffected upper limbs. However, the trabecular bone volume to total bone volume and cortical thickness values of the affected and unaffected sides were similar. Trabecular thickness tended to increase with time since disease diagnosis.

DISCUSSION

CRPS associated with significant alterations in the bone microstructure of the affected upper limb that may amplify as the duration of disease increases.

Zoledronic acid and alendronate sodium and the implications in orthodontic movement

OBJECTIVE

To evaluate orthodontic tooth movement (OTM) in rats treated with two types of bisphosphonates (BPs), alendronate sodium (A) and zoledronic acid (Z).

DESIGN

In all, 15 male Wistar rats were randomly divided into three groups. Group OTM+A: orthodontic tooth movement and subcutaneous administration of alendronate sodium (2.5 mg/kg); Group OTM+Z: orthodontic tooth movement and subcutaneous administration of zoledronic acid (0.02 mg/kg), and Group OTM: orthodontic tooth movement and subcutaneous injection of saline. The BPs were administered once a day during 25 days before OTM started and during 10 days of OTM. The left upper first molar was moved with a stainless-steel closed coil spring which delivered an initial force of 0.4N. OTM was measured with a digital caliper comparing the moved and the contralateral side. The histomorphometric analysis counted the number of osteoclasts, inflammatory cells, blood vessels and fibroblasts (n/10⁴  m² ) in periodontal ligament (PDL) of the distobuccal root.

RESULTS

A reduction of 58.3% of OTM was found in Group OTM+A and 99.6% in Group OTM+Z, when compared with Group OTM. There was a significant decrease of osteoclasts and inflammatory cells in BP-treated groups. Blood vessels and fibroblastic cells decreased mainly in Group OTM+Z.

CONCLUSION

Alendronate sodium and zoledronic acid have similar effects on the periodontal tissue during orthodontic treatment in rats. Especially, zoledronic acid can affect orthodontic tooth movement.

Three-Component Reaction of Benzylamines, Diethyl Phosphite and Triethyl Orthoformate: Dependence of the Reaction Course on the Structural Features of the Substrates and Reaction Conditions

The reaction between benzyl amines, triethyl orthoformate, and diethyl phosphite affords either bisphosphonic (compound 1) or N-benzylaminobenzylphosphonic (compound 2) acid depending on the reaction conditions. The final output of the reaction can be manipulated by the choice of reaction conditions, particularly the molar ratio of substrates.

Zoledronic Acid Treatment in Primary Bone Marrow Edema Syndrome

Primary bone marrow edema syndrome (BMES) is characterized by the combination of joint pain and distinctive magnetic resonance imaging changes. It has been suggested that the use of bisphosphonate drugs reduce symptom severity. Our objective was to review cases of patients diagnosed with BMES in the last 7 years who had been treated with zoledronic acid. Access to a pharmaceutical database was gained in order to obtain a list of zoledronic acid prescriptions. Based on clinical and MRI criteria for BMES, patients were selected. Baseline pain intensity was evaluated on a scale of 0 to 3 and was also assessed after 3 and 12 months. Functional recovery was evaluated by noting if a patient had returned to carrying out his or her normal daily activities. Out of 633 patients, 17 cases of BMES were identified (8 men), with a median age of 54 ± 14.1 years. The most frequently affected joint was the ankle (9), followed by the hip. Sixteen patients presented with moderate to severe pain initially. Of those patients, 13 had no pain after 12 months. Zoledronic acid is a option in the management of BMES, since 75% of patients treated with it presented with a complete response.

Treatment of complex regional pain syndrome type I with bisphosphonates

Complex regional pain syndrome type I (CRPS-I) is a common and disabling disorder affecting a peripheral limb, usually developing after a trauma to an extremity. CRPS-I is characterised by presence of spontaneous pain, allodynia and hyperalgesia, disproportionate to the inciting event and by a variety of autonomic disturbances and trophic abnormalities. The pathophysiology of CRPS-I has not been fully understood. Experimental models have suggested that an initial triggering event may produce the release of proinflammatory neuropeptides and cytokines, generating a sort of neurogenic inflammation. Thereafter, increased microvascular permeability and intramedullary pressure, reduced oxygen extraction and cellular hypoxia maintain and make the disease worse, producing metabolic tissue acidosis. In this context, it is probable that, far from being a key player, the sympathetic nervous system contributes interacting with these mechanisms and producing vasomotor disturbances. Bisphosphonates (BPs) are potent inhibitors of osteoclastic activity widely used for the management of osteoporosis and other metabolic bone diseases. Their primary pharmacological action is the reduction of bone turnover. An enhanced osteoclastic activity has never been clearly demonstrated in CRPS-I. Therefore, it is likely that the positive effects of BPs in this condition are not related to their antiresorptive properties, but to a more complex interaction between these pharmacological agents and the pathophysiological mechanisms underlying CRPS-I. Results of several clinical trials have suggested the potential beneficial effects of BPs in CRPS-I. In five randomised controlled trials, oral and intravenous alendronate and intravenous clodronate, pamidronate and neridronate demonstrated to be effective in reducing pain and improving physical function in patients presenting with CRPS-I, with a good profile of safety and tolerability. Although these trials have a number of limitations, including the small samples enrolled, there is sufficient evidence to support the use of BPs as agents of choice in the management of CRPS-I.

One-pot and highly regio-selective 1,3-dipole cycloaddition of azomethine ylide generated in situ to tetraethyl vinylidenebisphosphonate (VBP) catalyzed by cerium(iv) oxide

Higly regio-selective heterocyclic bisphosphonates are obtained in moderate yields (30–70%). The structures of the targeted molecules are characterized by NMR (such as COSY, HSQC, and HMBC), IR and MS.