Vesnarinone is a selective inhibitor of macrophage TNF(alpha) release

Pathologic role of stressed-induced glucocorticoids in drug-induced liver injury in mice

We previously reported that acetaminophen (APAP)-induced liver injury (AILI) in mice is associated with a rise in serum levels of the glucocorticoid (GC), corticosterone. In the current study, we provide evidence that endogenous GC play a pathologic role in AILI. Specifically, pretreatment of mice with the GC receptor (GCR) inhibitor, RU486 (mifepristrone), protected normal but not adrenalectomized mice from AILI, while pretreatment with dexamethasone, a synthetic GC, exacerbated AILI. RU486 did not affect the depletion of whole liver reduced GSH or the formation of APAP-protein adducts. It also had no effects on the formation of reactive oxygen species or the depletion of mitochondrial GSH or ATP. While RU486 pretreatment also protected against halothane-induced liver injury, it exacerbated concanavalin A (ConA)- and carbon tetrachloride (CCl(4))-induced liver injury, demonstrating the complexity of GC effects in different types of liver injury.

CONCLUSION

These results suggest that under certain conditions, elevated levels of GC might represent a previously unappreciated risk factor for liver injury caused by APAP and other drugs through the diverse biological processes regulated by GCR.

Cardiac cachexia: a systematic overview

Cardiac cachexia as a terminal stage of chronic heart failure carries a poor prognosis. The definition of this clinical syndrome has been a matter of debate in recent years. This review describes the ongoing discussion about this issue and the complex pathophysiology of cardiac cachexia and chronic heart failure with particular focus on immunological, metabolic, and hormonal aspects at the intracellular and extracellular level. These include regulators such as neuropeptide Y, leptin, melanocortins, ghrelin, growth hormone, and insulin. The regulation of feeding is discussed as are nutritional aspects in the treatment of the disease. The mechanisms of wasting in different body compartments are described. Moreover, we discuss several therapeutic approaches. These include appetite stimulants like megestrol acetate, medroxyprogesterone acetate, and cannabinoids. Other drug classes of interest comprise angiotensin-converting enzyme inhibitors, beta-blockers, anabolic steroids, beta-adrenergic agonists, anti-inflammatory substances, statins, thalidomide, proteasome inhibitors, and pentoxifylline.

Future prospects of anticytokine therapy in chronic heart failure

Several lines of evidence suggest that chronic heart failure is a state of chronic inflammation. Indeed, various pro-inflammatory markers, including the cytokines TNF-alpha, and interleukin 6 and 1, are activated in the course of the disease. In chronic heart failure, these substances are frequently induced even before the classical neurohormones angiotensin II and noradrenaline. Although the recently published anti-TNF-alpha trials with etanercept and infliximab have called the beneficial effects of targeting single cytokines into question, the overactive immune system remains a promising target for therapeutic interventions, which aim at slowing down disease progression. Broader approaches are required. These comprise targeting bacterial lipopolysaccharide (endotoxin) that enters the circulation through the oedematous gut wall, immune modulation therapy with patient-derived whole blood exposed to oxidative stress, 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors (the so-called statins) and a number of other substances including pentoxifylline and thalidomide.

Clinical characteristics of vesnarinone

Congestive heart failure is a common condition with a poor prognosis. Its high rates of morbidity and mortality produce a huge societal burden. Current pharmacological treatment approaches are based on angiotensin-converting enzyme inhibitors, diuretics and digoxin, but up to 5% of patients may have refractory disease with persistent symptoms at rest. Such patients with advanced-stage disease may be candidates for treatment with the novel agent vesnarinone, a mixed phosphodiesterase inhibitor and ion-channel modifier that has modest, dose-dependent, positive inotropic activity, but minimal negative chronotropic activity. Vesnarinone improves ventricular performance most in patients with the worst degree of heart failure. However, before the initiation of vesnarinone therapy, risk-benefit profiles in individual patients should be considered, because in two large-scale studies [i.e. of the high dosage used in the Vesnarinone Study Group Trial (VSGT), and of both dosages used in the Vesnarinone Trial (VEST)] a dose-dependent increase in mortality was identified for vesnarinone 30-120 mg/day. The two studies also found significant vesnarinone-induced, short-term improvements in quality of life (QOL) in patients with refractory end-stage heart failure. Such patients are the most willing to trade-off a slightly increased risk of mortality for improved QOL. It is thus in these patients with refractory end-stage heart failure that vesnarinone may ultimately establish an important treatment role. However, detailed further investigation of the overall place of vesnarinone in heart failure management, with particular reference to the clinical potential of vesnarinone plus beta-blocker combination therapy, for example, is certainly warranted.

Vesnarinone: a differentiation-inducing anti-cancer drug

Vesnarinone has been shown to be a unique anti-proliferating, differentiation-inducing and apoptosis inducing drug against several human malignancies, including leukemia and several solid tumors. Furthermore, vesnarinone potentiates the effect of conventional cytotoxic chemotherapy or radiation therapy. Combination of differentiation-inducing therapy by vesnarinone with conventional chemotherapy or radiation therapy might be second- or third-line therapy in patients with advanced cancer. Analysis of the molecular mechanisms of the tumor differentiation therapy by vesnarinone might provide selective and targeted molecules for novel tumor dormancy therapy.

Interferon-alpha 2b and vesnarinone influence levels of tumor necrosis factor-alpha, apoptosis, or interleukin 6 in ESKOL, a hairy cell leukemic cell line. A potential cytokine and oncogene relationship regulating apoptosis is suggested

The in vitro effects of interferon-alpha (IFN) on levels of secreted interleukin 6 (IL-6), tumor necrosis factor-alpha (TNF alpha), and nuclear matrix proteins (NMP) were examined in ESKOL, a B-lymphoblastoid cell line resembling hairy cell leukemia (HCL). IFN enhances differentiation in ESKOL, decreases TNF alpha levels, decreases apoptosis, increases IL-6 levels, and down regulates the expression of several oncogenes. Vesnarinone (Ves), a TNF alpha repressor, lowers TNF-alpha and decreases apoptosis in the same cell line. ESKOL exhibits enhanced apoptosis and reduced B-cell lymphomas (Bcl-2) levels over WIL-2. IL-6 and TNFalpha have been shown to decrease and increase apoptosis in B-cells respectively; however, treatment of ESKOL with these cytokines had no significant effect on apoptosis. We suggest that IFN decreases apoptosis by mechanisms involving enhanced IL-6 and Bcl-2 levels, decreased TNF alpha and the down regulation of apoptotic oncogenes, including c-myc.

Vesnarinone suppresses TNF-induced activation of NF-kappa B, c-Jun kinase, and apoptosis

Vesnarinone, a synthetic quinolinone derivative used in the treatment of cardiac failure, exhibits immunomodulatory, anti-inflammatory, and cell growth regulatory properties. The mechanisms underlying these properties are not understood, but due to the critical role of nuclear transcription factor NF-kappa B in these responses, we hypothesized that vesnarinone must modulate NF-kappa B activation. We investigated the effect of vesnarinone on NF-kappa B activation induced by inflammatory agents. Vesnarinone blocked TNF-induced activation of NF-kappa B in a concentration- and time-dependent manner. This effect was mediated through inhibition of phosphorylation and degradation of I kappa B alpha, an inhibitor of NF-kappa B. The effects of vesnarinone were not cell type specific, as it blocked TNF-induced NF-kappa B activation in a variety of cells. NF-kappa B-dependent reporter gene transcription activated by TNF was also suppressed by vesnarinone. The TNF-induced NF-kappa B activation cascade involving TNF receptor 1-TNF receptor associated death domain-TNF receptor associated factor 2 NF-kappa B-inducing kinase-IKK was interrupted at the TNF receptor associated factor 2 and NF-kappa B-inducing kinase sites by vesnarinone, thus suppressing NF-kappa B reporter gene expression. Vesnarinone also blocked NF-kappa B activation induced by several other inflammatory agents, inhibited the TNF-induced activation of transcription factor AP-1, and suppressed the TNF-induced activation of c-Jun N-terminal kinase and mitogen-activated protein kinase kinase. TNF-induced cytotoxicity, caspase activation, and lipid peroxidation were also abolished by vesnarinone. Overall, our results indicate that vesnarinone inhibits activation of NF-kappa B and AP-1 and their associated kinases. This may provide a molecular basis for vesnarinone's ability to suppress inflammation, immunomodulation, and growth regulation.

The effect of vesnarinone on TNF alpha production in human peripheral blood mononuclear cells and microglia: a preclinical study for the treatment of multiple sclerosis

Vesnarinone (OPC-8212) is a synthetic quinolinone derivative with inotropic and immunomodulatory effects. Vesnarinone has been shown to inhibit tumor necrosis factor-alpha (TNF alpha) produced by mitogen stimulated macrophages, and to inhibit phosphodiesterase (PDE) type III in cardiac muscle. TNF alpha and interferon-gamma (IFNgamma) have been implicated in the pathogenesis of autoimmune diseases, and both cytokines are targets for therapeutic intervention. IFNgamma can enhance autoimmune disease through direct effects, and indirectly by priming macrophages to produce TNF alpha. In this study, we demonstrate that while vesnarinone enhances basal TNF alpha levels, it inhibits TNF alpha production in peripheral blood mononuclear cells from multiple sclerosis (MS) patients and healthy donors stimulated with lipopolysaccharide (LPS) or primed with IFNgamma and stimulated with suboptimal doses of LPS. In addition, vesnarinone inhibited TNF alpha production in primary adult human microglial cultures. However, in contrast to rolipram, another TNF alpha inhibiting agent, vesnarinone failed to inhibit TNF alpha production by myelin basic protein specific T-cell lines. As oral TNF inhibitors are currently being considered in the USA for clinical application in MS, the implications of our findings on the development of vesnarinone for treatment of MS are discussed.

Effects of vesnarinone on cytokine production and activation of murine microglia

Tumor necrosis factor alpha (TNF alpha) is considered to play a critical role in the development of various pathological processes in the central nervous system (CNS), such as neuronal degeneration, demyelination and gliosis. In order to search for agents which suppress TNF alpha production in the CNS for future treatment of these pathological conditions, the effects of a synthetic oral inotropic agent, vesnarinone, on murine microglia were examined. Vesnarinone significantly suppressed TNF alpha production by microglia in a dose-dependent manner, without affecting their viability, enzyme activity or expression of the major histocompatibility complex. Since the reported maximum serum concentration is high enough to suppress TNF alpha production in vitro (about 20 microM) after oral administration of the therapeutic dose of vesnarinone, this drug will be useful to treat intractable neurological diseases such as neurodegenerative disorders, multiple sclerosis or HIV-related neurological disorders.

Association of tumour necrosis factor alpha and its receptors with thymidine phosphorylase expression in invasive breast carcinoma

Angiogenesis is an essential requirement for tumour growth and metastasis and is regulated by a complex network of factors produced by both stromal cells and neoplastic cells within solid tumours. The cytokine tumour necrosis factor alpha (TNF-alpha) and the enzyme thymidine phosphorylase (TP) are two factors known to promote tumour angiogenesis. We have demonstrated recently that high numbers of tumour-associated macrophages (TAMs) are significantly associated with increased tumour angiogenesis and poor prognosis in invasive carcinoma of the breast. We have also shown that TAMs are a major source of TNF-alpha in invasive breast carcinomas, and that macrophage-like stromal cells as well as tumour cells synthesize TP in such tumours. However, little is known of the factors that regulate the production or activity of these factors in the tumour microenvironment. As TNF-alpha has been shown to up-regulate TP expression in tumour cells in vitro we performed an immunohistochemical study to investigate the possibility that TNF-alpha may be involved in the regulation of TP expression by malignant breast epithelial cells in vivo. To do this, we used a cocktail of non-neutralizing monoclonal anti-TNF-alpha antibodies to visualize both TNF-alpha-expressing macrophages and TNF-alpha bound to its receptors on tumour cells and endothelial cells in a series of 93 invasive carcinomas of the breast. A semiquantitative grading system was then used to compare these staining patterns with that for TP in the same biopsies. TNF-alpha immunoreactivity was also compared with various important tumour variables known to relate to outcome in this disease (microvessel density, node status, grade, stage, receptor status and macrophage infiltration), as well as relapse-free and overall survival data for these patients. Our data show significant positive correlations between TNF-alpha bound to its receptors on tumour cells and: (1) TP protein production by tumour cells, and (2) axillary lymph node status (i.e. metastasis). These results suggest that tumour cell responsiveness to TNF-alpha produced by neighbouring TAMs may play a part in the regulation of TP expression by tumour cells as well as their metastatic behaviour. This may explain, in part, the relationship between increased macrophage infiltration and angiogenesis in breast cancer, and further supports the contention that TAMs may represent an important target for future anti-angiogenic therapies.

Down-regulation of tumor necrosis factor-alpha, moderate reduction of interleukin-1beta, but not interleukin-6 or interleukin-10, by glucan immunomodulators curdlan sulfate and lentinan

The effects of glucan-based immunomodulators curdlan sulfate (CRDS) and lentinan on cytokine production stimulated by lipopolysaccharide (LPS) in bacillus Calmette-Guerin (BCG)-primed mice were investigated. Pretreatment with CRDS or lentinan before LPS administration induced a striking inhibition of up to 89% of circulating tumor necrosis factor-alpha (TNF), a moderate reduction of 25% of interleukin (IL)-1beta, no significant differences in IL-6 or IL-10 levels, and a marked depression of chemiluminescence activity. Animals receiving CRDS prior to infection with alpha-hemolysin positive Escherichia coli inhibited measurable TNF production by 63%. The ability of CRDS and lentinan to significantly reduce the TNF production in vivo indicates the potential of glucans in possible therapeutic strategies that are based on down-regulation of TNF.