Microglia Depletion Attenuates the Pro-Resolving Activity of the Formyl Peptide Receptor 2 Agonist AMS21 Related to Inhibition of Inflammasome NLRP3 Signalling Pathway: A Study of Organotypic Hippocampal Cultures.

Microglial cells have been demonstrated to be significant resident immune cells that maintain homeostasis under physiological conditions. However, prolonged or excessive microglial activation leads to disturbances in the resolution of inflammation (RoI). Formyl peptide receptor 2 (FPR2) is a crucial player in the RoI, interacting with various ligands to induce distinct conformational changes and, consequently, diverse biological effects. Due to the poor pharmacokinetic properties of endogenous FPR2 ligands, the aim of our study was to evaluate the pro-resolving effects of a new ureidopropanamide agonist, compound AMS21, in hippocampal organotypic cultures (OHCs) stimulated with lipopolysaccharide (LPS). Moreover, to assess whether AMS21 exerts its action via FPR2 specifically located on microglial cells, we conducted a set of experiments in OHCs depleted of microglial cells using clodronate. We demonstrated that the protective and anti-inflammatory activity of AMS21 manifested as decreased levels of lactate dehydrogenase (LDH), nitric oxide (NO), and proinflammatory cytokines IL-1ß and IL-6 release evoked by LPS in OHCs. Moreover, in LPS-stimulated OHCs, AMS21 treatment downregulated NLRP3 inflammasome-related factors (CASP1, NLRP3, PYCARD) and this effect was mediated through FPR2 because it was blocked by the FPR2 antagonist WRW4 pre-treatment. Importantly this beneficial effect of AMS21 was only observed in the presence of microglial FPR2, and absent in OHCs depleted with microglial cells using clodronate. Our results strongly suggest that the compound AMS21 exerts, at nanomolar doses, protective and anti-inflammatory properties and an FPR2 receptor located specifically on microglial cells mediates the anti-inflammatory response of AMS21. Therefore, microglial FPR2 represents a promising target for the enhancement of RoI.

Monocyte-derived macrophages contribute to the deterioration of immunological liver injury in mice.

BACKGROUND & AIMS: Autoimmune hepatitis (AIH) is characterized by hepatocyte destruction, leading to lymphocyte and macrophage accumulation in the liver. However, the specific mechanisms of how macrophages participate in the occurrence and development of AIH are still unclear. In this study, we investigated the effect of monocyte-derived macrophages on Con A-induced immunological liver injury in mice and we hypothesized that inhibition of CCR2 with the dual CCR2/5 inhibitor, cenicriviroc (CVC), would attenuate Con A-induced hepatitis in mice by reducing the recruitment of monocytes into the liver. METHODS: Murine experimental AIH was established by concanavalin A (Con A) injection intravenously. Macrophages were depleted by injection of clodronate liposomes in Con A-treated mice. Moreover, inhibition of the CCR2/5 signaling pathway in Con A mice is achieved by CVC. Liver injury and infiltration of monocyte-derived macrophages were assessed by serum transaminase levels, histopathology, immunohistochemistry, flow cytometry, RT-qPCR, ELISA, TUNEL assay and dihydroethidium staining. RESULTS: The number of macrophages in the mouse livers increased in the Con A-induced hepatitis mouse model, and flow cytometry showed a significant increase in the proportion of F4/80loCD11bhi monocyte-derived macrophages, while there was no significant change in the proportion of F4/80hiCD11blo Kupffer cells. After the depletion of liver macrophages by clodronate liposomes, the levels of serum ALT and AST, and the degree of liver tissue damage were alleviated in Con A-treated mice. Furthermore, Con A leaded an increase in the expression of a group of CC chemokines in mouse livers, and the elevation of CCL2 was prevented with the depletion of macrophages. Additionally, CVC reduced macrophage infiltration in the liver and ameliorated Con A-induced liver injury. Meanwhile, CVC reduced the apoptosis and oxidative damage of hepatocytes caused by Con A. CONCLUSIONS: Our research demonstrates that there is an increase in monocyte-derived macrophages in the livers due to the monocyte infiltration resulted from the activation of the CCL2-CCR2 axis in Con A-induced liver injury mouse model. Pharmacological inhibition of CCR2 monocyte recruitment by CVC efficiently ameliorates the hepatic inflammation, indicating the therapeutic potential of CVC in patients with AIH.

Retrospective evaluation of acute kidney injury in horses treated with nonnitrogenous bisphosphonates (2013-2020): 8 cases.

OBJECTIVE: To describe a population of horses with acute kidney injury (AKI) following administration of bisphosphonates including clinical signs, clinicopathologic data, treatment, and outcome. DESIGN: Retrospective study from August 2013 to July 2020. SETTING: Veterinary university teaching hospital. ANIMALS: Eight adult horses with AKI following administration of nonnitrogenous bisphosphonates. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Five horses received intramuscular clodronate (5/8; 62.5%) and 3 horses received intravenous tiludronate (3/8; 37.5%). Six horses (6/8; 75%) received concurrent nonsteroidal anti-inflammatory drugs. The most common initial presenting complaint was poor appetite (6/8; 75%), followed by abnormal urination (2/8; 25%). At the time of initial evaluation, the mean serum or plasma creatinine was 451.72 ± 190.06 µmol/L (5.11 ± 2.15 mg/dL) and BUN was 18.84 ± 8.85 mmol/L (52.75 ± 24.77 mg/dL). Five horses (5/6; 83.3%) had either an increased number of red blood cells (n = 4) or hemoprotein (n = 1) in the urine. All horses were treated with IV isotonic, balanced crystalloids either as a bolus, continuous rate infusion, or a combination of the 2. Seven horses (7/8; 87.5%) survived the initial episode of AKI and 1 horse (1/8; 12.5%) was euthanized. Of the 7 surviving horses, 2 horses (2/7; 28.5%) went on to develop chronic renal dysfunction. Warmblood breeds were overrepresented in the AKI group (P = 0.008; odds ratio: 11.5, 95% confidence interval: 1.8-72.1), when compared to horses that received bisphosphonates during the study period and did not develop AKI. CONCLUSIONS: Bisphosphonate administration, with or without concurrent nonsteroidal anti-inflammatory drugs, can be associated with AKI in horses. Serum creatinine should be monitored prior to and following bisphosphonate treatment to minimize this risk. Further evaluation of renal function is warranted in horses that develop clinical signs of poor appetite, lethargy, or altered urination in the days following bisphosphonate treatment.

Intra-articular clodronate in patients with knee osteoarthritis non-responder to intra-articular hyaluronic acid - a case report series of 9 patients with 8-month follow-up.

Background: Osteoarthritis (OA) is a common disease in the elderly people, inducing pain and functional limitations. Clodronate (CLO) a first generation non-nitrogen containing bisphosphonate has been purposed as a treatment of OA, being effective on pain, inflammation, bone marrow oedema, osteophytosis and cartilage regeneration. Intra-muscular routes of CLO showed efficacy in the treatment of Knee OA (KOA) and erosive OA of the hand. In KOA intraarticular CLO at low doses (0.5-2 mg) showed efficacy as well as hyaluronic acid (HA), being able to improve the effectiveness if associated to HA. Methods: Nine Consecutive patients (4 female, 5 male, mean age 78,22) with KOA at 2nd or 3rd degree following Kellgren-Lawrance scale, non responder to HA and unintended to surgery. They were treated with intraarticular CLO at the weekly dose of 20 mg, plus lidocaine 1% in 5 cc of saline solution for a route of 5 weekly infil-trations, followed by a second route of 5 intraarticular infiltrations 3 months after the first course. Visual analog score (VAS) pain and Tegner-Lysholm Score (TLS) were used to assess changes following CLO treatment. Results: Baseline pain was 6,77/10, reduced to 1,09 at day 150 (after second course) and to 2,3/10 at day 240. TLS at baseline was 56,7/100, improved to 96,7 at day 150 and to 84,1 at day 240. At day 240 only 2 out of 9 patients had a negative judgement of the treatment and decided to stop it, while 7 were satisfied and available to a further course. There was no increase of consumption of anti-inflammatory or analgesic drugs. A short time lasting pain after the injections was registered in all patients. Conclusions: In a small cohort of patients affected by KOA, non responders to intraarticular HA a higher dose of intraarticular CLO in KOA showed good compliance, amelioration of pain and functionality.

Characteristics of activation of monocyte-derived macrophages versus microglia after mouse experimental intracerebral hemorrhage.

Both monocyte-derived macrophages (MDMs) and brain resident microglia participate in hematoma resolution after intracerebral hemorrhage (ICH). Here, we utilized a transgenic mouse line with enhanced green fluorescent protein (EGFP) labeled microglia (Tmem119-EGFP mice) combined with a F4/80 immunohistochemistry (a pan-macrophage marker) to visualize changes in MDMs and microglia after ICH. A murine model of ICH was used in which autologous blood was stereotactically injected into the right basal ganglia. The autologous blood was co-injected with CD47 blocking antibodies to enhance phagocytosis or clodronate liposomes for phagocyte depletion. In addition, Tmem119-EGFP mice were injected with the blood components peroxiredoxin 2 (Prx2) or thrombin. MDMs entered the brain and formed a peri-hematoma cell layer by day 3 after ICH and giant phagocytes engulfed red blood cells were found. CD47 blocking antibody increased the number of MDMs around and inside the hematoma and extended MDM phagocytic activity to day 7. Both MDMs and microglia could be diminished by clodronate liposomes. Intracerebral injection of Prx2 but not thrombin attracted MDMs into brain parenchyma. In conclusion, MDMs play an important role in phagocytosis after ICH which can be enhanced by CD47 blocking antibody, suggesting the modulation of MDMs after ICH could be a future therapeutic target.

Pentoxifylline and tocopherol (vitamin E) with/without clodronate for the management of osteoradionecrosis: A scoping review.

BACKGROUND: Treatment of osteoradionecrosis (ORN) is not a straightforward task, and it is unpredictable. However, a combination of pentoxifylline; an antioxidant drug, and tocopherol (vitamin E) works as a potent antifibrotic agent and have shown recently both significant and impressive results. AIMS: This scoping review aims to investigate the most prescribed regimen of pentoxifylline and tocopherol with/without clodronate for the management of ORN. METHODS: Ovid MEDLINE and EMBASE databases were used to retrieve eligible studies using planned search keywords. PROSPERO and Cohcarne library were also searched for ongoing or published systematic reviews, respectively. Included articles were grouped thematically according to the type of studies and accordingly they were summarized. RESULTS: A total of 27 articles met the inclusion criteria and included in the data analyses. All the included articles were published between 1997 and 2020. Of these 27 included studies, two were randomized control trials, two were systematic reviews, six were retrospective studies, five were observational studies, seven were narrative reviews, four were case reports, and lastly one was an in-vitro study. CONCLUSIONS: Treatment by PENTO (800 mg of pentoxifylline + 1000 IU of tocopherol) once daily for an early established ORN or PENTOCLO (PENTO regimen + 1600 mg of clodronate) once daily for the refractory/severe cases of ORN appears to be the most prescribed regimen used for the treatment of ORN using these drugs. These drugs appear safe, effective and inexpensive for the treatment of ORN.

Clodronate detection and effects on markers of bone resorption are prolonged following a single administration to horses.

BACKGROUND: Clodronate is a potent antiresorptive agent labelled for use in horses over 4 years of age, for the treatment of navicular syndrome. Concerns regarding the extra-label use of clodronate in equine athletes, such as racehorses, have been raised as inhibition of osteoclast activity by clodronate has been postulated to interfere with normal bone healing, which is imperative to the repair of microfractures. The paucity of data describing the long-term pharmacokinetics of clodronate and effects on biomarkers of bone resorption necessitates further study. OBJECTIVES: (1) To determine clodronate concentrations in blood and urine over a 6-month period in horses undergoing treadmill exercise and (2) to assess the effects of clodronate on protein biomarkers of bone remodelling in this same group of horses. STUDY DESIGN: Randomised controlled experimental study. METHODS: Seven exercised Thoroughbred horses received a single im administration of 1.8 mg/kg clodronate and four horses received an equivalent volume of saline. Blood and urine samples were collected prior to, during and for 182 days post drug administration for drug concentration determination using liquid chromatography-tandem mass spectrometry, and determination of protein biomarker (CTX-1 and TRAcP5B) concentrations. RESULTS: Clodronate was detectable in blood for 14-175 days and for up to 175 days in urine. For some horses, concentrations were nondetectable at one time point but detectable at a subsequent time point. The terminal serum half-life ranged from 1.80 to 283.9 days. CTX-1 concentrations were significantly higher, relative to baseline, in both treated and control groups while concentrations of TRAcP5B were significantly lower in the treated group. MAIN LIMITATIONS: Relatively small number of horses studied. CONCLUSIONS: Based on assessment of protein biomarkers, clodronate appears to influence osteoclasts at label doses. Furthermore, results of this study support racing regulations that preclude horses administered bisphosphonates for medical reasons, from racing for a prolonged period of time.

CONTEXTO: Clodronato é um agente antirreabsortivo potente e recomendado para o uso em cavalos com mais de 4 anos de idade, para o tratamento da síndrome do navicular. Há preocupação com o uso indiscriminado de clodronato em equinos atletas, como cavalos de corrida, já que a inibição da atividade dos osteoclastos pelo clodronato tem sido postulada em interferir na cicatrização óssea normal, o que é essencial para a cicatrização de microfraturas. A escassez de informação quanto às ações prolongadas do uso de clodronato e seus efeitos nos biomarcadores de reabsorção óssea requere mais estudos. OBJETIVOS: (1) Determinar a concentração de clodronato no sangue e urina por um período de 6 meses em cavalos submetidos ao exercício em esteira e (2) acessar os efeitos de clodronato nos biomarcadores de remodelação óssea no mesmo grupo de cavalos. DELINEAMENTO DO ESTUDO: Estudo controlado randomizado. METODOLOGIA: Sete cavalos Puro-Sangue Inglês em exercício receberam uma única dose im de 1.8 mg/kg de clodronato e 4 cavalos receberam um volume equivalente de solução fisiológica. Amostras de sangue e urina foram coletadas antes, durante e por 182 dias após a administração de clodronato. Valores de concentração da droga foram determinados utilizando cromatografia líquida-espectrometria de massa (LC-MS/MS), e determinação da concentração de biomarcadores (CTX-1 e TRAcP5B) também foi realizada. RESULTADOS: Clodronato foi detectado no sangue por 14-175 dias e por até 175 dias na urina. Para alguns equinos, a concentração foi não-detectável em um momento, mas detectável no próximo momento. O valor terminal da vida-média em soro foi 1.80-283.9 dias. A concentração de CTX-1 foi significativamente elevada, relativo às amostras iniciais, em ambos os grupos (tratamento e controle), enquanto as concentrações de TRAcP5B foram significativamente menores no grupo de cavalos tratados. PRINCIPAIS LIMITAÇÕES: Número relativamente pequenos de cavalos no estudo. CONCLUSÕES: Baseado nos resultados dos biomarcadores, clodronato parece influencia osteoclastos na dose recomendada. Além disso, os resultados deste estudo suportam o regulamento de cavalos de corrida que impedem que cavalos que receberam bifosfonatos por razão médica de competir por um período de tempo prolongado.

A systematic review and meta-analysis of interventional studies of bisphosphonates and denosumab in multiple myeloma and future perspectives.

Bisphosphonates (BPs) and denosumab (DENOS), due to their ability to inhibit osteoclast activity, are used to prevent skeletal complications in multiple myeloma (MM) patients. The NCBI PubMed, Web of Science, Scopus and ClinicalTrials.gov databases, were systematically searched for interventional studies, assessing the use of BP and DENOS in MM patients. Overall survival, disease progression, skeletal-related events, bone pain, osteonecrosis of the jaw (ONJ) and renal toxicity were the outcomes of interest. A total of 993 studies were retrieved and 43 were used for qualitative synthesis. Clodronate (CLOD) and zoledronic acid (ZOL) were effective in reducing skeletal complications compared to placebo. Results are mixed regarding the efficacy of pamidronate in reducing skeletal related events. ONJ rates were higher for ZOL, but under 5%, with CLOD having the safest profile. DENOS demonstrated non-inferiority to ZOL, in improving overall survival [pooled Hazard Ratio(HR) 1.02(95% CI 0.72,1.44)], progression free survival [pooled HR 0.92(95% CI 0.76,1.11)] and in reducing skeletal related events [pooled HR 1.03(95% CI 0.92,1.16)], with similar rates of ONJ and better safety profile regarding renal toxicity. Denosumab has comparable efficacy and safety with ZOL and may even replace BPs in the future, in the management of myeloma bone disease.

Doxorubicin-liposome combined with clodronate-liposome inhibits hepatocellular carcinoma through the depletion of macrophages and tumor cells.

Macrophages in the liver have capacities of capturing and phagocytosing nanocarriers. Macrophages also play an important role in the inflammatory microenvironment and in the tumorigenesis, development and progression of hepatocellular carcinoma (HCC). Several studies have shown that depletion of macrophages is a viable strategy for drug delivery and tumor microenvironment regulation. We prepared liposomes containing doxorubicin and clodronate using an ammonium sulfate gradient and thin film hydration method. The repressive therapeutic effects of liposomes were compared by intrasplenic injection at different stages of a primary HCC model induced by diethylnitrosamine (DEN) in rats. Doxorubicin-liposome (DOX-LIP) and clodronate-liposome (CL-LIP) about 180-200 nm were successfully prepared and characterized. We found that DOX-LIP combined with CL-LIP could effectively inhibit the occurrence and development of liver cancer without major organ damage and side effects. The combination of doxorubicin and clodronate liposomes notably decreased hepatic CD68 + macrophages, enriched DOX in plasma and accumulated it for a long time in the liver and spleen, thus improving the tumor microenvironment, inhibiting the activation of hepatic progenitor cells (HPCs) and promoting the apoptosis of tumor cells, and finally producing the inhibitory and therapeutic effects of HCC in rats. Results of this study were expected to provide a new prospect for the chemotherapy of HCC.

HMGA1 Promotes Macrophage Recruitment via Activation of NF-κB-CCL2 Signaling in Hepatocellular Carcinoma.

Background: Tumor-associated macrophages (TAMs) are known to generate an immune-suppressive tumor microenvironment (TME) and promote tumor progression. Hepatocellular carcinoma (HCC) is a devastating disease that evolves in the background of chronic inflammatory liver damage. In this study, we aimed to uncover the mechanism by which HCC cells recruit macrophages into the TME. Methods: Bioinformatic analysis was performed to identify differentially expressed genes related to macrophage infiltration. An orthotopic HCC xenograft model was used to determine the role of macrophages in HCC tumor growth. Clodronate liposomes were used to delete macrophages. Western blotting analysis, quantitative real-time PCR, and enzyme-linked immunosorbent assay were performed to determine the underlying mechanisms. Results: The high mobility group A1 (HMGA1) gene was identified as a putative modulator of macrophage infiltration in HCC. Deletion of macrophages with clodronate liposomes significantly abrogated the tumor-promoting effects of HMGA1 on HCC growth. Mechanistically, HMGA1 can regulate the expression of C-C Motif Chemokine Ligand 2 (CCL2), also referred to as monocyte chemoattractant protein 1 (MCP1), which is responsible for macrophage recruitment. Moreover, NF-κB was required for HMGA1-mediated CCL2 expression. Pharmacological or genetic inhibition of NF-κB largely blocked CCL2 levels in HMGA1-overexpressing HCC cells. Conclusions: This study reveals HMGA1 as a crucial regulator of macrophage recruitment by activating NF-κB-CCL2 signaling, proves that HMGA1-induced HCC aggressiveness dependents on the macrophage, and provide an attractive target for therapeutic interventions in HCC.

Tumor-associated macrophages (TAMs) modulate response to HER2-targeted agents in a humanized mouse model of breast cancer

PurposeTumor-associated macrophages (TAM) may participate to antitumor activity of anti-HER2-targeted therapies (Pertuzumab, Trastuzumab) in breast cancers harbouring HER-2 overexpression through antibody-dependent phagocytosis. Additive antitumor effect of concurrent cytotoxic chemotherapies, including Paclitaxel, may be counterbalanced by alteration in TAM infiltrate. The aim of this study is to evaluate the role of TAM in tumor response to anti-HER2-targeted therapies and chemotherapy in an experimental model of HER2-amplified breast cancer.MethodsA xenograft mouse model was built by subcutaneous injection of the SKBR-3 human HER2-amplified breast cancer cell line in Hu-CD34+ mice. Animals were randomized to receive weekly administration of Cremophor (control), Trastuzumab+Pertuzumab (TP), and Paclitaxel+Trastuzumab+Pertuzumab (PTP) with or without macrophage depletion with clodronate (C). At week 4, mice were euthanised and tumors were harvested for immunohistochemical analysis of TAM infiltration (RBP-J CD163 and CD68 for M1, M2, and overall TAM, respectively).ResultsTumor size was significantly lower in mice treated with TP, PTP, and PTP+C as compared to control, while no meaningful difference was observed in the TP+C arm. Analysis of TAM infiltrate showed significantly lower CD68 and CD163 expression in PTP, TP+C, and PTP+C as compared to TP and control arm. RBP-J expression was significantly decreased in mice treated with clodronate depletion.ConclusionsActivity of TP is modulated by TAM infiltrate, that is inhibited by concurrent administration of Paclitaxel. To enhance the effect of anti-HER2-targeted therapies and minimize chemotherapy-related side effects, modulation of TAM should be considered in novel therapeutic combinations.

Tumor-associated macrophages (TAMs) modulate response to HER2-targeted agents in a humanized mouse model of breast cancer.

PURPOSE: Tumor-associated macrophages (TAM) may participate to antitumor activity of anti-HER2-targeted therapies (Pertuzumab, Trastuzumab) in breast cancers harbouring HER-2 overexpression through antibody-dependent phagocytosis. Additive antitumor effect of concurrent cytotoxic chemotherapies, including Paclitaxel, may be counterbalanced by alteration in TAM infiltrate. The aim of this study is to evaluate the role of TAM in tumor response to anti-HER2-targeted therapies and chemotherapy in an experimental model of HER2-amplified breast cancer. METHODS: A xenograft mouse model was built by subcutaneous injection of the SKBR-3 human HER2-amplified breast cancer cell line in Hu-CD34+ mice. Animals were randomized to receive weekly administration of Cremophor (control), Trastuzumab+Pertuzumab (TP), and Paclitaxel+Trastuzumab+Pertuzumab (PTP) with or without macrophage depletion with clodronate (C). At week 4, mice were euthanised and tumors were harvested for immunohistochemical analysis of TAM infiltration (RBP-J CD163 and CD68 for M1, M2, and overall TAM, respectively). RESULTS: Tumor size was significantly lower in mice treated with TP, PTP, and PTP+C as compared to control, while no meaningful difference was observed in the TP+C arm. Analysis of TAM infiltrate showed significantly lower CD68 and CD163 expression in PTP, TP+C, and PTP+C as compared to TP and control arm. RBP-J expression was significantly decreased in mice treated with clodronate depletion. CONCLUSIONS: Activity of TP is modulated by TAM infiltrate, that is inhibited by concurrent administration of Paclitaxel. To enhance the effect of anti-HER2-targeted therapies and minimize chemotherapy-related side effects, modulation of TAM should be considered in novel therapeutic combinations.

18F-FDG PET/CT for early response assessment of jaw osteoradionecrosis after the PENTOCLO protocol: A promising imaging modality.

INTRODUCTION: The Pentoxifylline, Tocopherol and Clodronate protocol (PENTOCLO) showed promising results for jaw osteoradionecrosis (ORN) management. However, the clinical and radiological improvements are often delayed, leading to unwanted long-term treatment, with potential loss of opportunity for more radical surgical treatments. Our objective was to assess the diagnosis performance of 18F-FDG PET/CT to early predict ORN response to the PENTOCLO protocol. MATERIALS AND METHODS: All patients from our center who were treated with the PENTOCLO protocol and with a 18F-FDG PET/CT performed at diagnosis and three months after the end of antibiotherapy were retrospectively included. The PENTOCLO protocol was always combined with prior appropriate antibiotherapy for six weeks. The healing endpoint was divided into healing, stability or worsening, according to the combination of clinical and radiological assessments at the date of last follow-up. For each patient, the difference between the maximal standardized uptake value (ΔSUVmax) of the ORN lesion at three months and baseline were computed. Diagnostic performance of 18F-FDG PET/CT was evaluated by sensitivity, specificity and the area under the receiver operating characteristic curve (ROC-AUC) of ΔSUVmax. RESULTS: 24 patients were included with an average follow-up of 29.3 months. The healing, stability and worsening rate were 25%, 62.5% and 12.5% respectively. The AUC for discriminating worsening vs stability or healing was 0.92 (IC95 [0.81-1.00]). A ΔSUVmax greater than or equal to 0 was predictive of a worsening with a sensitivity and specificity of 84 and 66% respectively. CONCLUSION: 18F-FDG PET/CT imaging could be useful for early prediction of PENTOCLO treatment resistance with appropriate antibiotherapy.

Role of the Osteochondral Unit in the Pathogenesis of Osteoarthritis: Focus on the Potential Use of Clodronate.

Osteoarthritis (OA) is a chronic disease characterized by inflammation and progressive deterioration of the joint. The etiology of OA includes genetic, phlogistic, dismetabolic and mechanical factors. Historically, cartilage was considered the target of the disease and therapy was aimed at protecting and lubricating the articular cartilage. The osteochondral unit is composed of articular cartilage, calcified cartilage, and subchondral and trabecular bone, which work synergistically to support the functional loading of the joint. Numerous studies today show that OA involves the osteochondral unit, with the participation therefore of the bone in the starting and progression of the disease, which is associated with chondropathy. Cytokines involved in the process leading to cartilage damage are also mediators of subchondral bone edema. Therefore, OA therapy must be based on the use of painkillers and bisphosphonates for both the control of osteometabolic damage and its analgesic activity. Monitoring of the disease of the osteochondral unit must be extensive, since bone marrow edema can be considered as a marker of the evolution of OA. In the present review, we discuss some of the pathogenetic mechanisms associated with osteoarthritis, with a particular focus on the osteochondral unit and the use of clodronate.

[VNUT Is a Therapeutic Target for Type 2 Diabetes and NASH].

ATP, used in cells as an energy currency, also acts as an extracellular signaling molecule. Studies of purinergic receptor subtypes have revealed that purinergic chemical transmission plays important roles in various cell types. The vesicular nucleotide transporter (VNUT), the ninth transporter in the SLC17 organic anion transporter family, is essential for vesicular ATP storage and its subsequent release. The VNUT is localized on the membrane of secretory vesicles and actively transports ATP into vesicles using an electrochemical gradient of protons supplied by vacuolar proton ATPase (V-ATPase) as a driving force. ATP acts as a damage-associated molecular pattern (DAMPs), contributing to the persistence of chronic inflammation. Chronic inflammation induces systemic insulin resistance, which is the underlying pathology of type 2 diabetes and non-alcoholic fatty liver disease (NAFLD), ranging from simple steatosis to non-alcoholic steatohepatitis (NASH). We previously demonstrated that ATP transported in insulin granules via the VNUT negatively regulates insulin secretion. We also found that hepatocytes release ATP in a VNUT-dependent manner, which elicits hepatic insulin resistance and inflammation. VNUT-knockout mice exhibited improved glucose tolerance and were resistant to the development of high fat diet-induced NAFLD. In this article, we summarize recent advances in our understanding of the mechanism of the VNUT, the development of inhibitors, and its pathological involvement in type 2 diabetes and NAFLD. The pharmacological inhibition of the VNUT may represent a potential therapeutic approach for the treatment of metabolic diseases.

The Rationale for the Intra-Articular Administration of Clodronate in Osteoarthritis.

BACKGROUND: Several pharmacological therapeutic approaches have been proposed to manage osteoarthritis (OA), including intra-articular (IA) injections. Although the discovery of clodronate, a bisphosphonate, dates back to the 1960s and the effects of its IA administration have been investigated for decades in animal models, mechanisms of action of this drug are not quite clear, particularly in OA. This scoping review is an overview of the biological as well as the clinical role of clodronic acid in OA. METHOD: A scoping review based on the PRISMA-ScR (Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews) model was performed to characterize the mechanisms of action of IA clodronate in OA and to evaluate its efficacy from a clinical point of view. RESULTS: Several effects of clodronate have been observed in animal models of OA, including depletion of synovial lining cells that results in reduced production of chemokines (IL-1, TNF- α), growth factors (TGF-ß, BMP 2/4), and metalloproteases (MMP 2/3/9); prevention of cartilage damage, synovial hyperplasia, and proteoglycans loss; reduction in joint inflammation, joint swelling, and osteophyte formation. From a clinical perspective, patients with knee OA treated with IA clodronate experienced improvements in pain and joint mobility. CONCLUSION: Clodronate appears to have different mechanisms of action interfering with the pathogenic processes contributing to OA development and progression. This intervention demonstrated positive effects for patients affected by knee OA.

[Predictive factors for mandibular osteoradionecrosis after irradiation of head and neck cancers]. / Facteurs prédictifs de l'ostéoradionécrose mandibulaire après irradiation des cancers des voies aérodigestives supérieures.

The identification of the different risk factors for mandibular osteoradionecrosis (ORN) must be done before and after the management of patients with head and neck cancer. Various clinical criteria for this severe radiation-induced complication are related to the patient (intrinsic radiosensitivity, malnutrition associated with thin weight loss, active smoking intoxication, microcapillary involvement, precarious oral status, hyposalivation) and/or related to the disease (oral cavity, large tumor size, tumor mandibular invasion). Therapeutic risk factors are also associated with a higher risk of ORN (primary tumor surgery, concomitant radio-chemotherapy, post-irradiation dental avulsion, preventive non-observance with the absence of stomatological follow-up and daily installation of gutters fluoride and, non-observance curative healing treatments). Finally, various dosimetric studies have specified the parameters in order to target the dose values distributed in the mandible, which increases the risk of ORN. An mean mandibular dose greater than 48-54Gy and high percentages of mandibular volume receiving 40 to 60Gy appear to be discriminating in the risk of developing an ORN.

The use of pentoxifylline, tocopherol and clodronate in the management of osteoradionecrosis of the jaws.

AIMS: Medical management of osteoradionecrosis (ORN) via pentoxifylline, tocopherol (PENTO) and clodronate (PENTOCLO) has shown both promise and early positive outcomes. We aimed to determine clinical outcomes for patients with established ORN managed solely via PENTO or PENTOCLO. METHODS: The study retrospectively reviewed and collected data from the medical records of 169 patients diagnosed with ORN and treated via medical management. Patients that received any additional interventions such as surgery or hyperbaric oxygen were not included. RESULTS: Medical management led to healed ORN in 54.4% (n = 92/169) of patients after an average of 12.9 months. Outcome comparison between PENTO and PENTOCLO identified the former regime to be significantly superior (p = 0.0001). There is an inverse relationship with increasing ORN severity and healing with medical management (p < 0.0001) with oropharyngeal cancer (p = 0.0347) patients responding favourably via this approach. Infection had a critical role in the final outcome with those healing requiring 1.3 antibiotic prescriptions, while those that had disease progression requiring 4.3 prescriptions. CONCLUSION: Medical management is a viable treatment option for ORN. It appears to be most effective in Notani I and non-infected ORN. When healing was not achieved the regime was able to stabilise the condition.

Clodronate Treatment Prevents Vaginal Hypersensitivity in a Mouse Model of Vestibulodynia.

INTRODUCTION: Improved understanding of vestibulodynia pathophysiology is required to develop appropriately targeted treatments. Established features include vulvovaginal hyperinnervation, increased nociceptive signalling and hypersensitivity. Emerging evidence indicates macrophage-neuron signalling contributes to chronic pain pathophysiology. Macrophages are broadly classified as M1 or M2, demonstrating pro-nociceptive or anti-nociceptive effects respectively. This study investigates the impact of clodronate liposomes, a macrophage depleting agent, on nociceptive signalling in a mouse model of vestibulodynia. METHODS: Microinjection of complete Freund's adjuvant (CFA) at the vaginal introitus induced mild chronic inflammation in C57Bl/6J mice. A subgroup was treated with the macrophage depleting agent clodronate. Control mice received saline. After 7 days, immunolabelling for PGP9.5, F4/80+CD11c+ and F4/80+CD206+ was used to compare innervation density and presence of M1 and M2 macrophages respectively in experimental groups. Nociceptive signalling evoked by vaginal distension was assessed using immunolabelling for phosphorylated MAP extracellular signal-related kinase (pERK) in spinal cord sections. Hyperalgesia was assessed by visceromotor response to graded vaginal distension. RESULTS: CFA led to increased vaginal innervation (p < 0.05), increased pERK-immunoreactive spinal cord dorsal horn neurons evoked by vaginal-distension (p < 0.01) and enhanced visceromotor responses compared control mice (p < 0.01). Clodronate did not reduce vaginal hyperinnervation but significantly reduced the abundance of M1 and M2 vaginal macrophages and restored vaginal nociceptive signalling and vaginal sensitivity to that of healthy control animals. CONCLUSIONS: We have developed a robust mouse model of vestibulodynia that demonstrates vaginal hyperinnervation, enhanced nociceptive signalling, hyperalgesia and allodynia. Macrophages contribute to hypersensitivity in this model. Macrophage-sensory neuron signalling pathways may present useful pathophysiological targets.

Clodronate.

Two early observations about the first generation bisphosphonate, clodronate, suggested that it would likely have clinical utility; specifically, it was a more potent anti-resorptive but a less potent inhibitor of mineralisation than its predecessor etidronate. The known mechanism of action differs from that of the later nitrogen-containing bisphosphonates, as clodronate is metabolised intracellularly to a toxic analog of adenosine triphosphate, AppCCl2p, which causes mitochondrial dysfunction, impaired cellular energy metabolism and osteoclast apoptosis. For pre-clinical studies in a variety of disease models, liposomal clodronate has become the agent of choice for macrophage depletion, for example in a recent study to enhance haematopoietic chimerism and donor-specific skin allograft tolerance in a mouse model. For clinical use, clodronate was developed in oral and injectable formulations; while poorly absorbed from the gastro-intestinal tract, its absorption at 1-3% of the administered dose is approximately three-fold higher than for nitrogen-containing bisphosphonates. Following an early setback due to an erroneous association with toxic adverse events, a number of successful clinical studies have established clodronate, predominantly in its oral formulations, as a highly successful treatment in Paget's disease, hypercalcaemia (benign and malignant), multiple myeloma, and early or metastatic breast cancer. Novel uses in other disease areas, including veterinary use, continue to be explored.