An endogenous regulator of inflammation, resolvin E1, modulates osteoclast differentiation and bone resorption

Background and purpose:

The inflammation-resolving lipid mediator resolvin E1 (RvE1) effectively stops inflammation-induced bone loss in vivo in experimental periodontitis. It was of interest to determine whether RvE1 has direct actions on osteoclast (OC) development and bone resorption.

Experimental approach:

Primary OC cultures derived from mouse bone marrow were treated with RvE1 and analysed for OC differentiation, cell survival and bone substrate resorption. Receptor binding was measured using radiolabelled RvE1. Nuclear factor (NF)-κB activation and Akt phosphorylation were determined with western blotting. Lipid mediator production was assessed with liquid chromatography tandem mass spectrometry.

Key results:

OC growth and resorption pit formation were markedly decreased in the presence of RvE1. OC differentiation was inhibited by RvE1 as demonstrated by decreased number of multinuclear OC, a delay in the time course of OC development and attenuation of receptor activator of NF-κB ligand-induced nuclear translocation of the p50 subunit of NF-κB. OC survival and apoptosis were not altered by RvE1. Messenger RNA for both receptors of RvE1, ChemR23 and BLT₁ is expressed in OC cultures. Leukotriene B₄ (LTB₄) competed with [³H]RvE1 binding on OC cell membrane preparations, and the LTB₄ antagonist {"type":"entrez-nucleotide","attrs":{"text":"U75302","term_id":"1857248","term_text":"U75302"}}U75302 prevented RvE1 inhibition of OC growth, indicating that BLT₁ mediates RvE1 actions on OC. Primary OC synthesized the RvE1 precursor 18R-hydroxy-eicosapentaenoic acid and LTB₄. Co-incubation of OC with peripheral blood neutrophils resulted in transcellular RvE1 biosynthesis.

Conclusions and implications:

These results indicate that RvE1 inhibits OC growth and bone resorption by interfering with OC differentiation. The bone-sparing actions of RvE1 are in addition to inflammation resolution, a direct action in bone remodelling.     

The rush to adrenaline: drugs in sport acting on the beta-adrenergic system

Athletes attempt to improve performance with drugs that act on the beta-adrenergic system directly or indirectly. Of three beta-adrenoceptor (AR) subtypes, the beta(2)-AR is the main target in sport; they have bronchodilator and anabolic actions and enhance anti-inflammatory actions of corticosteroids. Although demonstrable in animal experiments and humans, there is little evidence that these properties can significantly improve performance in trained athletes. Their actions may also be compromised by receptor desensitization and by common, naturally occurring receptor mutations (polymorphisms) that can influence receptor signalling and desensitization properties in individuals. Indirectly acting agents affect release and reuptake of noradrenaline and adrenaline, thereby influencing all AR subtypes including the three beta-ARs. These agents can have potent psychostimulant effects that provide an illusion of better performance that does not usually translate into improvement in practice. Amphetamines and cocaine also have considerable potential for cardiac damage. beta-AR antagonists (beta-blockers) are used in sports that require steadiness and accuracy, such as archery and shooting, where their ability to reduce heart rate and muscle tremor may improve performance. They have a deleterious effect in endurance sports because they reduce physical performance and maximum exercise load. Recent studies have identified that many beta-AR antagonists not only block the actions of agonists but also activate other (mitogen-activated PK) signalling pathways influencing cell growth and fate. The concept that many compounds previously regarded as 'blockers' may express their own spectrum of pharmacological properties has potentially far-reaching consequences for the use of drugs both therapeutically and illicitly.     

The selectivity of ��-adrenoceptor agonists at human ��1-, ��2- and ��3-adrenoceptors

Background and purpose:

There are two important properties of receptor–ligand interactions: affinity (the ability of the ligand to bind to the receptor) and efficacy (the ability of the receptor–ligand complex to induce a response). Ligands are classified as agonists or antagonists depending on whether or not they have efficacy. In theory, it is possible to develop selective agonists based on selective affinity, selective intrinsic efficacy or both. This study examined the affinity and intrinsic efficacy of 31 β-adrenoceptor agonists at the three human β-adrenoceptors to determine whether the current agonists are subtype selective because of affinity or intrinsic efficacy.

Experimental approach:

Stable clonal CHO-K1 cell lines, transfected with either the human β₁, β₂ or β₃-adrenoceptor, were used, and whole-cell [³H]-CGP 12177 radioligand binding and [³H]-cAMP accumulation were measured.

Key results:

Several agonists were found to be highly subtype selective because of selective affinity (e.g. salmeterol and formoterol, for the β₂-adrenoceptor over the β₁ or β₃), while others (e.g. isoprenaline) had little affinity–selectivity. However, the intrinsic efficacy of salmeterol, formoterol and isoprenaline was similar across all three receptor subtypes. Other ligands (e.g. denopamine for β₁; clenbuterol, AZ 40140d, salbutamol for β₂) were found to have subtype-selective intrinsic efficacy. Several ligands appeared to activate two agonist conformations of the β₁- and β₃-adrenoceptors.

Conclusions and implications:

There are agonists with subtype selectivity based upon both selective affinity and selective intrinsic efficacy. Therefore, there is scope to develop better selective agonists based upon both selective affinity and selective intrinsic efficacy.This article is commented on by Kenakin, pp. 1045–1047 of this issue. To view this commentary visit http://dx.doi.org/10.1111/j.1476-5381.2010.00764.x     

Inhibition of osteoclast differentiation and bone resorption by a novel lysophosphatidylcholine derivative, SCOH

Osteoclasts are multinucleated cells formed by multiple steps of cell differentiation from progenitor cells of hematopoietic origin. Intervention in osteoclast differentiation is considered as an effective therapeutic approach to the treatment for bone diseases involving osteoclasts. In this study, we found that the organic compound (S)-1-lyso-2-stearoylamino-2-deoxy-sn-glycero-3-phosphatidylcholine (SCOH) inhibited osteoclast differentiation. The inhibitory effect of SCOH was observed in mouse bone marrow cell cultures supported either by coculturing with osteoblasts or by adding macrophage colony stimulating factor (M-CSF) and receptor activator of nuclear factor kappaB ligand (RANKL). M-CSF and RANKL activate the ERK, Akt, and NF-kappaB signal transduction pathways, and SCOH suppressed this activation. SCOH also inhibited the bone resorptive activity of differentiated osteoclasts. It attenuated bone resorption, actin ring formation, and survival of mature osteoclasts. Reduced activation of Akt and NF-kappaB and decreased induction of XIAP were observed in mature osteoclasts treated with SCOH. Thus, this novel phosphatidylcholine derivative may be useful for treating bone-resorption diseases.     

Blockade of β-adrenoceptors restores the GRK2-mediated adrenal α(2) -adrenoceptor-catecholamine production axis in heart failure

BACKGROUND AND PURPOSE

Sympathetic nervous system (SNS) hyperactivity is characteristic of chronic heart failure (HF) and significantly worsens prognosis. The success of β-adrenoceptor antagonist (β-blockers) therapy in HF is primarily attributed to protection of the heart from the noxious effects of augmented catecholamine levels. β-Blockers have been shown to reduce SNS hyperactivity in HF, but the underlying molecular mechanisms are not understood. The GPCR kinase-2 (GRK2)–α₂adrenoceptor–catecholamine production axis is up-regulated in the adrenal medulla during HF causing α₂-adrenoceptor dysfunction and elevated catecholamine levels. Here, we sought to investigate if β-blocker treatment in HF could lower SNS activation by directly altering adrenal GRK2 levels.

EXPERIMENTAL APPROACH

Four weeks after myocardial infarction-induced HF, adult rats were randomized to 10-week treatment with vehicle (HF/C) or bisoprolol (HF/B). Cardiac function and dimensions were measured. In heart and adrenal gland, GRK2 levels were assessed by RT-PCR and Western blotting and adrenoceptors studied with radioligand binding. Catecholamines and α₂adrenoceptors in adrenal medulla chromaffin cell cultures were also measured.

KEY RESULTS

Bisoprolol treatment ameliorated HF-related adverse cardiac remodelling and reduced plasma catecholamine levels, compared with HF/C rats. Bisoprolol also attenuated adrenal GRK2 overexpression as observed in HF/C rats and increased α₂adrenoceptor density. In cultures of adrenal medulla chromaffin cells from all study groups, bisoprolol reversed HF-related α₂adrenoceptor dysfunction. This effect was reversed by GRK2 overexpression.

CONCLUSION AND IMPLICATIONS

Blockade of β-adrenoceptors normalized the adrenal α₂adrenoceptor-catecholamine production axis by reducing GRK2 levels. This effect may contribute significantly to the decrease of HF-related sympathetic overdrive by β−blockers.     

Inhibition of osteoclast differentiation and bone resorption by tanshinone IIA isolated from Salvia miltiorrhiza Bunge

Osteoclasts, multinuclear cells specialized for bone resorption, differentiate from the monocyte/macrophage lineage of hematopoietic cells. Intervention in osteoclast differentiation is considered an effective therapeutic approach to the treatment of bone diseases involving osteoclasts. In this study, we found that tanshinone IIA, originating from Salvia miltiorrhiza Bunge, inhibited the differentiation of osteoclasts. Addition of tanshinone IIA to the osteoclast precursor culture caused a significant decrease in the level of calcitonin receptor, c-Src, and integrin beta3 mRNA, which are normally upregulated during the osteoclast differentiation dependent on RANKL (receptor activator of nuclear factor kappa B ligand). RANKL activated the ERK, Akt, and NF-kappaB signal transduction pathways in osteoclast precursor cells, and tanshinone IIA suppressed this activation. Tanshinone IIA also inhibited the bone resorptive activity of differentiated osteoclasts, which was accompanied with the disruption of the actin ring. Thus, tanshinone IIA has the potential to ameliorate bone-resorption diseases in vivo by reducing both the number and activity of osteoclasts.     

Tanshinone IIA therapeutically reduces LPS-induced acute lung injury by inhibiting inflammation and apoptosis in mice

Aim:

To study the effects of tanshinone IIA (TIIA) on lipopolysaccharide (LPS)-induced acute lung injury in mice and the underlying mechanisms.

Methods:

Mice were injected with LPS (10 mg/kg, ip), then treated with TIIA (10 mg/kg, ip). Seven hours after LPS injection, the lungs were collected for histological study. Protein, LDH, TNF-α and IL-1β levels in bronchoalveolar lavage fluid (BALF) and myeloperoxidase (MPO) activity in lungs were measured. Cell apoptosis and Bcl-2, caspase-3, NF-κB and HIF-1α expression in lungs were assayed.

Results:

LPS caused marked histological changes in lungs, accompanied by significantly increased lung W/D ratio, protein content and LDH level in BALF, and Evans blue leakage. LPS markedly increased neutrophil infiltration in lungs and inflammatory cytokines in BALF. Furthermore, LPS induced cell apoptosis in lungs, as evidenced by increased TUNEL-positive cells, decreased Bcl-2 content and increased cleaved caspase-3 content. Moreover, LPS significantly increased the expression of NF-κB and HIF-1α in lungs. Treatment of LPS-injected mice with TIIA significantly alleviated these pathological changes in lungs.

Conclusion:

TIIA alleviates LPS-induced acute lung injury in mice by suppressing inflammatory responses and apoptosis, which is mediated via inhibition of the NF-κB and HIF-1α pathways.     

Blockade of adipocyte differentiation by cordycepin

BACKGROUND AND PURPOSE

Cordyceps militaris has the potential to suppress differentiation of pre-adipocytes. However, the active entities in the extract and the underlying mechanisms of its action are not known. Hence, we investigated whether and how cordycepin (3′-deoxyadenosine), a constituent of C. militaris, inhibits adipogenesis.

EXPERIMENTAL APPROACH

Differentiation of 3T3-L1 pre-adipocytes and pre-adipocytes in primary cultures was induced by Insulin, dexamethasone and IBMX, and these were used as in vitro models of adipogenesis. The effects of cordycepin on adipogenesis were examined with particular focus on the regulation of CCAAT/enhancer-binding protein β (C/EBPβ) and PPARγ.

KEY RESULTS

Cordycepin suppressed the lipid accumulation and induction of adipogenic markers that occurred on differentiation of pre-adipocytes and also blocked the down-regulation of a pre-adipocyte marker. This anti-adipogenic effect was reversible and mediated by an adenosine transporter, but not A₁, A₂ or A₃ adenosine receptors. This effect of cordycepin was not reproduced by other adenosine-related substances, including ATP, ADP and adenosine. Early induction of the adipogenic C/EBPβ–PPARγ pathway was suppressed by cordycepin. Blockade of mTORC1 via inhibition of PKB (Akt) and activation of AMP kinase was identified as the crucial upstream event targeted by cordycepin. In addition to its negative effect on adipogenesis, cordycepin suppressed lipid accumulation in mature adipocytes.

CONCLUSIONS AND IMPLICATIONS

These results suggest that the anti-adipogenic effects of cordycepin occur through its intervention in the mTORC1-C/EBPβ–PPARγ pathway. Cordycepin, by blocking both adipogenesis and lipid accumulation, may have potential as a therapeutic agent for effective treatment of obesity and obesity-related disorders.     

Testosterone protects rat hearts against ischaemic insults by enhancing the effects of alpha(1)-adrenoceptor stimulation

BACKGROUND AND PURPOSE: Testosterone alleviates symptoms in patients with ischaemic heart disease. Androgen receptors are present in the heart, and testosterone upregulates gene expression of cardiac beta(1)-adrenoceptors. We hypothesize that testosterone may confer cardioprotection by interacting with adrenoceptors.EXPERIMENTAL APPROACH: In isolated perfused hearts and ventricular myocytes from orchidectomized rats without or with testosterone (200 microg/100 g) replacement, we first determined the effect of ischaemia/reperfusion in the presence of noradrenaline (10(-7) M). Then we determined the contribution of interactions between testosterone and alpha(1)- or beta(1)-adrenoceptors in cardiac injury/protection (infarct size, release of lactate dehydrogenase, viability of myocytes, recovery of contractile function and incidence of arrhythmias) upon ischaemia/reperfusion by pharmacological manipulation using selective adrenoceptor agonists (alpha(1)-adrenoceptor agonist: phenylephrine 10(-6) M; non-selective beta-adrenoceptor agonist: isoprenaline 10(-7) M) and antagonists (alpha(1): prazosin or benoxathian 10(-6) M; beta(1): CGP 20712A 5 x 10(-7) M). We also determined the expression of alpha(1) and beta(1)-adrenoceptor in the hearts from rats with and without testosterone.KEY RESULTS: Testosterone reduced injury induced by ischaemia/reperfusion and noradrenaline. This was achieved by enhancing the beneficial effect of alpha(1)-adrenoceptor stimulation, which was greater than the deleterious effect of beta(1)-adrenoceptor stimulation (also enhanced by testosterone). The effects of testosterone were abolished or attenuated by blockade of androgen receptors. Testosterone also enhanced the expression of alpha(1A) and beta(1)-adrenoceptor.CONCLUSIONS AND IMPLICATIONS: Testosterone conferred cardioprotection by upregulating the cardiac alpha(1)-adrenoceptor and enhancing the effects of stimulation of this adrenoceptor. The effect of testosterone was at least partly mediated by androgen receptors.     

Z-ligustilide attenuates lipopolysaccharide-induced proinflammatory response via inhibiting NF-KB pathway in primary rat microglia

Aim:

To investigate the anti-inflammatory effect of Z-ligustilide (LIG) on lipopolysaccharide (LPS)-activated primary rat microglia.

Methods:

Microglia were pretreated with LIG 1 h prior to stimulation with LPS (1 μg/mL). After 24 h, cell viability was tested with MTT, nitric oxide (NO) production was assayed with Griess reagent, and the content of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and monocyte chemoattractant protein (MCP-1) was measured with ELISA. Protein expression of the nuclear factor-κB (NF-κB) p65 subunit, cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS) was detected with immunocytochemistry 1 h or 24 h after LPS treatment.

Results:

LIG showed a concentration-dependent anti-inflammatory effect in LPS-activated microglia, without causing cytotoxicity. Pretreatment with LIG at 2.5, 5, 10, and 20 μmol/L decreased LPS-induced NO production to 75.9%, 54.4%, 43.1%, and 47.6% (P<0.05 or P< 0.01), TNF-α content to 86.2%, 68.3%, 40.1%, and 39.9% (P<0.01, with the exception of 86.2% for 2.5 μmol/L LIG), IL-1β content to 31.5%, 27.7%, 0.6%, and 0% (P<0.01), and MCP-1 content to 84.4%, 50.3%, 45.1%, and 42.2% (P<0.05 or P<0.01), respectively, compared with LPS treatment alone. LIG (10 μmol/L) significantly inhibited LPS-stimulated immunoreactivity of activated NF-κB, COX-2, and iNOS (P<0.01 vs LPS group).

Conclusion:

LIG exerted a potent anti-inflammatory effect on microglia through inhibition of NF-κB pathway. The data provide direct evidence of the neuroprotective effects of LIG and the potential application of LIG for the treatment of the neuroinflammatory diseases characterized by excessive microglial activation.     

Both alpha1 and alpha2-adrenoceptors mediate the cardiovascular responses to noradrenaline microinjected into the bed nucleus of the stria terminal of rats

BACKGROUND AND PURPOSE: We have previously shown that noradrenaline microinjected into the bed nucleus of stria terminalis (BST) elicited pressor and bradycardiac responses in unanaesthetized rats. In the present study, we investigated the subtype of adrenoceptors that mediates the cardiovascular response to noradrenaline microinjection into the BST. EXPERIMENTAL APPROACH: Cardiovascular responses following noradrenaline microinjection into the BST of male Wistar rats were studied before and after BST pretreatment with different doses of the selective alpha(1)-adrenoceptor antagonist WB4101, the alpha(2)-adrenoceptor antagonist RX821002, the combination of WB4101 and RX821002, the non-selective beta-adrenoceptor antagonist propranolol, the selective beta(1)-adrenoceptor antagonist CGP20712 or the selective beta(2)-adrenoceptor antagonist ICI118,551. KEY RESULTS: Noradrenaline microinjected into the BST of unanaesthetized rats caused pressor and bradycardiac responses. Pretreatment of the BST with different doses of either WB4101 or RX821002 only partially reduced the response to noradrenaline. However, the response to noradrenaline was blocked when WB4101 and RX821002 were combined. Pretreatment with this combination also shifted the resulting dose-effect curve to the left, clearly showing a potentiating effect of this antagonist combination. Pretreatment with different doses of either propranolol or CGP20712 increased the cardiovascular responses to noradrenaline microinjected into the BST. Pretreatment with ICI118,551 did not affect cardiovascular responses to noradrenaline. CONCLUSION AND IMPLICATIONS: The present results indicate that alpha(1) and alpha(2)-adrenoceptors mediate the cardiovascular responses to noradrenaline microinjected into the BST. In addition, they point to an inhibitory role played by the activation of local beta(1)-adrenoceptors in the cardiovascular response to noradrenaline microinjected into the BST.     

Alpha-4/beta-1 and alpha-L/beta-2 integrins mediate cytokine induced lung leukocyte-epithelial adhesion and injury

BACKGROUND AND PURPOSE: Injury to the alveolar epithelium is a critical feature of acute lung injury (ALI). Using a cytokine model of ALI we demonstrated previously that newly recruited mononuclear phagocytes (MNP) contributed to lung inflammation and injury. We hypothesized that cytokines delivered into the alveolar airspace would have multiple effects on the lung that may contribute to lung injury. EXPERIMENTAL APPROACH: Intratracheal cytokine insufflation and leukocyte adoptive transfer in vivo were combined with in vitro analyses of lung epithelial cell-MNP adhesion and injury. Lung inflammatory injury was assessed by histology, leukocyte infiltration, and release of LDH and RAGE. KEY RESULTS: Cytokine insufflation was associated with apparent MNP-epithelial adhesion, up-regulation of alveolar ICAM-1 and VCAM-1, and the release of LDH and RAGE into the bronchoalveolar lavage. Insufflation of small molecule integrin antagonists suppressed adhesion of MNP and modulated release of LDH and RAGE. Adoptive transfer of MNP purified from cytokine insufflated lungs into leukopenic rats demonstrated the requirement of MNP for release of LDH that was not induced by cytokine alone. Corroboration that disrupting the ICAM/LFA1 interaction or the VCAM/VLA4 interaction blocked MNP-epithelial cell interaction and injury was obtained in vitro using both blocking monoclonal antibodies and the small molecule integrin antagonists, BIO5192 and XVA143. CONCLUSIONS AND IMPLICATIONS: MNP recruited following cytokine insufflation contributed to lung injury. Further, integrin antagonists reduced alveolar epithelial cell injury induced during lung inflammation. Intratracheal delivery of small molecule antagonsists of leukocyte-epithelial adhesion that prevent lung injury may have significant clinical utility.     

Chronic treatment in vivo with β-adrenoceptor agonists induces dysfunction of airway β(2) -adrenoceptors and exacerbates lung inflammation in mice

BACKGROUND AND PURPOSE

Inhalation of a β-adrenoceptor agonist (β-agonist) is first-line asthma therapy, used for both prophylaxis against, and acute relief of, bronchoconstriction. However, repeated clinical use of β-agonists leads to impaired bronchoprotection and, in some cases, adverse patient outcomes. Mechanisms underlying this β₂-adrenoceptor dysfunction are not well understood, due largely to the lack of a comprehensive animal model and the uncertainty as to whether or not bronchorelaxation in mice is mediated by β₂-adrenoceptors. Thus, we aimed to develop a mouse model that demonstrated functional β-agonist-induced β₂-adrenoceptor desensitization in the context of allergic inflammatory airway disease.

EXPERIMENTAL APPROACH

We combined chronic allergen exposure with repeated β-agonist inhalation in allergen-treated BALB/C mice and examined the contribution of β₂-adrenoceptors to albuterol-induced bronchoprotection using FVB/NJ mice with genetic deletion of β₂-adrenoceptors (KO). Associated inflammatory changes – cytokines (ELISA), cells in bronchoalevolar lavage and airway remodelling (histology) and β₂-adrenoceptor density (radioligand binding) – were also measured.

KEY RESULTS

β₂-Adrenoceptors mediated albuterol-induced bronchoprotection in mice. Chronic treatment with albuterol induced loss of bronchoprotection, associated with exacerbation of the inflammatory components of the asthma phenotype.

CONCLUSIONS AND IMPLICATIONS

This animal model reproduced salient features of human asthma and linked loss of bronchoprotection with airway pathobiology. Accordingly, the model offers an advanced tool for understanding the mechanisms of the effects of chronic β- agonist treatment on β-adrenoceptor function in asthma. Such information may guide the clinical use of β-agonists and provide insight into development of novel β-adrenoceptor ligands for the treatment of asthma.     

Pleiotropic action(s) of the bradycardic agent ivabradine: cardiovascular protection beyond heart rate reduction

The bradycardic agent ivabradine has proved to be of benefit in experimental models with the end points of ischaemic myocardial blood flow and contractile function, infarct size, post-infarct remodelling and atherosclerosis. The benefits to ischaemic myocardial blood flow and contractile function are strictly heart rate dependent; those on infarct size are partly heart rate independent. The heart rate dependency of ivabradine's benefit for atherosclerotic vascular function is contradictory, and that on post-infarct remodelling is entirely unclear.     

Improvement of solubility and dissolution properties of clotrimazole by solid dispersions and inclusion complexes

Solid dispersions of a slightly water-soluble drug, clotrimazole, were prepared in different weight ratios using polyethyleneglycol 4000 and different molecular weight polyvinyl pyrrolidones as carriers. Moreover, binary and ternary β-cyclodextrin complexes were prepared in different molar ratios. Both solid dispersions and β-cyclodextrin complexes were prepared by solvent evaporation technique. A phase solubility method was used to evaluate the effect of the tested carriers on the aqueous solubility of clotrimazole. The dissolution of all the preparations was tested using the USP paddle method. The selected solid dispersions and inclusion complexes were characterized by differential scanning calorimetry and X-ray powder diffractometry studies, and results clarified the role of the tested carriers in decreasing the crystallinity of clotrimazole and complexing abilities. Based on physical characters and in vitro drug release pattern, polyvinylpyrrolidone solid dispersions (1:1 weight ratio) and ternary cyclodextrin complexes (clotrimazole-β-cyclodextrin complexes with either polymer, 1:1 molar ratio) were selected as ideal batches for suppositories. Suppocire AM/50 mg carbopol 940, was chosen as a suppository base and the suppositories were prepared by molding technique. The prepared suppositories were characterized for weight variation, softening time and drug content. All these properties were found to be ideal. The in vitro drug release pattern was determined in citrate buffer (pH 4.5) containing 1% sodium lauryl sulfate. The in vitro release of clotrimazole from its solid dispersions and inclusion complexes incorporated suppositories was markedly improved when compared to the intact drug incorporated suppositories. Polyvinyl pyrrolidone solid dispersions incorporated suppositories were found to possess excellent antifungal activity.     

Quercetin suppresses bone resorption by inhibiting the differentiation and activation of osteoclasts

Although quercetin has suppressed bone resorption in several animal studies, its target cells and the mechanism of its action related to bone resorption has not been fully elucidated. We investigated the effect of quercetin on the differentiation and activation of osteoclasts. We used cocultures of mouse spleen cells and ST2 cells, and cultures of osteoclast progenitor cells [M-CSF-dependent (MD) cells from mouse bone marrow and murine monocytic RAW 264 (RAW) cells]. Quercetin dose-dependently inhibited osteoclast-like (OCL) cell formation at 2-5 microM concentration in both the coculture and MD cell culture. Quercetin inhibited the increase of tartrate-resistant acid phosphatase (TRAP) activity of mononuclear preosteoclasts (pOCs) induced by receptor activator of nuclear factor-kappaB (NF-kappaB) ligand (RANKL) in both MD and RAW cell cultures. Quercetin reversely induced the disruption of actin rings in OCLs. Quercetin also suppressed both pit formation induced by osteoclasts on dentine slices and PTH-stimulated (45)Ca release in mouse long bone cultures. These results suggest that osteoclast progenitors as well as mature osteoclasts, are quercetin's target cells in relation to bone resorption, and that quercetin's suppressive effect on bone resorption results from both its inhibitory effect on the differentiation of osteoclast progenitor cells into pOCs and from its disruptive effect on actin rings in mature osteoclasts.