WO2005079767A2 - Means for modulation of the effects of opioid-like substances - Google Patents

Abstract

The present invention relates to the use of an opiate-receptor antagonist for the preparation of a pharmaceutical composition for treating or preventing heart failure in a human subject or multi-organ dysfunction syndrome in a subject. The invention also relates to a method for treating a human subject suffering from heart failure or multi-organ dysfunction syndrome comprising the step of administering to said subject an opiate-receptor antagonist in a thera­peutically effective dosage.

Description

New PCT application Universitatsklinikum Mϋnster Our ref.: 1019-03

Means for modulation ofthe effects of opioid-like substances

The present invention relates to the use of an opioid receptor antagonist for the preparation of a pharmaceutical composition for treating or preventing heart failure in a human subject or multi-organ dysfunction syndrome in a subject. The invention also relates to a method for treating a human subject suffering from heart failure or multi-organ dysfunction syndrome comprising the step of administering to said subject an opioid receptor antagonist in a thera- peutically effective dosage.

Heart failure (HF) is a major world wide public health problem. Heart failure is primarily a disease of the elderly. Heart failure is the most common Medicare diagnosis-related group (DRG), and more Medicare dollars are spent for the diagnosis and treatment of HF than for any other diagnosis. The ACC and the AHA first published guidelines for the evaluation and management of HF in 1995. Since that time, a great deal of progress has been made in development of both pharmacological and nonpharmacological approaches to treatment for this common, costly, disabling, and generally fatal disorder. Heart failure is a complex clinical syndrome that can result from any structural or functional cardiac disorder that impairs the ability ofthe ventricle to fill with or eject blood. The cardinal manifestations of HF are dyspnea and fatigue, which may limit exercise tolerance, and fluid retention, which may lead to pulmonary congestion and peripheral edema. Both abnormalities can impair the functional capacity and quality of life of affected individuals, but they do not necessarily dominate the clinical picture at the same time. Some patients have exercise intolerance but little evidence of fluid retention, whereas others complain primarily of edema and report few symptoms of dyspnea or fatigue. Because not all patients have volume overload at the time of initial or subsequent evaluation, the term "heart failure" is preferred over the older term "congestive heart failure." The clinical syndrome of HF may result from disorders of the pericardium, myocardium, endocardium, or great vessels, but the majority of patients with HF have symptoms due to an impairment of left ventricular function. Heart failure may be associated with a wide spectrum of left ventricular functional abnormalities, which may range from the predominantly diastolic dysfunction of a normal-sized chamber with normal emptying but impaired filling to the predominantly systolic dysfunction of a markedly dilated chamber with reduced wall motion but preserved filling. In many patients, abnormalities of systolic and diastolic dysfunction coexist. The principal hallmark of patients with predominant systolic dysfunction is a depressed left ventricular ejection fraction (generally less than 40%); in contrast, patients with predominant diastolic dysfunction typically have an impairment of 1 or more indices of ventricular filling. Patients with predominant diastolic dysfunction have a different natural history and require different treatment strategies than patients with predominant systolic dysfunction. Coronary artery disease is the cause of HF in about two thirds of patients with left ventricular systolic dysfunction. The remainder have a nonischemic cardiomyopathy, which may have an identifiable cause (e.g., hypertension, thyroid disease, valvular disease, alcohol use, or myocarditis) or may have no known cause (e.g., idiopathic dilated cardiomyopathy). It should be emphasized that HF is not equivalent to cardiomyopathy or to left ventricular dysfunction; these latter terms describe possible structural reasons for the development of HF. Instead, HF is a clinical syndrome that is characterized by specific symptoms (dyspnea and fatigue) and signs (fluid retention). There is no diagnostic test for HF, because it is largely a clinical diagnosis that is based on a careful history and physical examination. The approach that is most commonly used to- quantify the degree of functional limitation imposed by HF is one first developed by the NYHA. This system assigns patients to 1 of 4 functional classes, depending on the degree of effort needed to elicit symptoms: patients may have symptoms of HF at rest (class IN), on less-than-ordinary exertion (class III), on ordinary exertion (class II), or only at levels of exertion that would limit normal individuals (class I). Although the functional class tends to deteriorate over periods of time, most patients with HF do not typically show an uninterrupted and inexorable worsening of symptoms. Instead, the severity of symptoms characteristically fluctuates even in the absence of changes in medications, and changes in medications and diet can have marked favorable or adverse effects on functional capacity in the absence of measurable changes in ventricular function. The mechanisms responsible for the exercise intolerance of patients with chronic HF have not been clearly defined. Although HF is generally regarded as a hemodynamic disorder, many studies have indicated that there is a poor relation between cardiac performance and the symptoms produced by the disease. Patients with a very low ejection fraction are frequently asymptomatic, whereas patients with preserved left ventricular systolic function may have severe disability. The apparent discordance between the severity of systolic dysfunction and the degree of functional impairment is not well understood but may be explained in part by alterations in ventricular distensibility, valvular regurgitation, pericardial restraint, and right ventricular function. In addition, in ambulatory patients, many noncardiac factors may contribute importantly to exercise intolerance. These factors include but are not limited to changes in peripheral vascular function, skeletal muscle physiology, pulmonary dynamics, and neurohormonal and reflex autonomic activity. The existence of these noncardiac factors may explain why the hemodynamic improvement produced by therapeutic agents in patients with chronic HF may not be immediately or necessarily translated into clinical improvement. Although pharmacological interventions may produce rapid changes in hemodynamic variables, signs and symptoms may improve slowly over weeks or months or not at all. Left ventricular dysfunction begins with some injury to or stress on the myocardium and is generally a progressive process, even in the absence of a new identifiable insult to the heart. The principal manifestation of such progression is a change in the geometry of the left ventricle such that the chamber dilates, hypertrophies, and becomes more spherical — a process referred to as cardiac remodeling. This change in chamber size not only increases the hemodynamic stresses on the walls of the failing heart and depresses its mechanical performance but also increases the magnitude of regurgitant flow through the mitral valve. These effects, in turn, serve to sustain and exacerbate the remodeling process. Cardiac remodeling generally precedes the development of symptoms (occasionally by months or even years), continues after the appearance of symptoms, and contributes importantly to worsening of symptoms despite treatment. What factors can accelerate the process of left ventricular remodeling? Although many mechanisms may be involved, there is substantial evidence that the activation of endogenous neurohormonal systems may play an important role in cardiac remodeling and thereby in the progression of HF. Patients with HF have elevated circulating or tissue levels of norepinephrine, angiotensin II, aldosterone, endothelin, vasopressin, and cytokines, which can act (alone or in concert) to adversely affect the structure and function of the heart. These neurohormonal factors not only increase the hemodynamic stresses on the ventricle by causing sodium retention and peripheral vasoconstriction, but may also exert direct toxic effects on cardiac cells and stimulate myocardial fibrosis, which can further alter the architecture and impair the performance of the failing heart. The evolution and progression of HF can be appropriately characterized by considering 4 stages of the disease as described in the Introduction and:

Stage A: Patients at high risk of developing HF because of the presence of conditions which are strongly associated with the development of HF. Such patients have no identified structural or functional abnormalities ofthe pericardium, myocardium, or cardiac valves and have never shown signs or symptoms of HF. (Examples; Systemic hypertension; coronary artery disease; diabetes mellitus; history of cardiotoxic drug or alcohol abuse; personal history of rheumatic fever; family history of cardiomyopathy)

Stage B: Patients who have developed structural heart disease that is strongly associated with the development of HF but who have never shown signs or symptoms of HF. (Examples; Left ventricular hypertrophy or fibrosis; left ventricular dilatation or hypocontractility; asymptomatic valvular heart disease; previous myocardial infarction)

Stage C: Patients who have current or prior symptoms of HF associated with underlying structural heart systolic disease. (Examples; Dyspnea or fatigue due to left ventricular dysfunction; asymptomatic patients who are undergoing treatment for prior symptoms of HF. Stage D: Patients with advanced structural heart disease and marked symptoms of HF at rest despite maximal medical therapy and who require specialized interventions. (Examples; Patients who are frequently hospitalized for HF and cannot be safely discharged from the hospital; patients in the hospital awaiting heart transplantation; patients at home receiving continuous intravenous support for symptom relief or being supported with a mechanical circulatory assist device; patients in a hospice setting for the management of HF.

This staging system recognizes that HF, like coronary artery disease, has established risk factors and structural prerequisites; that the evolution of HF has asymptomatic and symptomatic phases; and that specific treatments targeted at each stage can reduce the morbidity and mortality of HF. In general, patients with left ventricular dysfunction or HF present to the physician in 1 of 3 ways:

(1) With a syndrome of decreased exercise tolerance. Most patients with HF seek medical attention with complaints of a reduction in their effort tolerance due to dyspnea and/or fatigue. These symptoms, which may occur at rest or during exercise, may be attributed inappropriately by the patient and/or physician to aging, to other physiological abnormalities (e.g., deconditioning), or to other disorders (e.g., pulmonary disease). Therefore, in a patient whose exercise capacity is limited by dyspnea or fatigue, the physician must determine whether the principal cause is HF or another abnormality. Elucidation of the precise reason for exercise intolerance can be difficult because these disorders may coexist in the same patient. A clear distinction can sometimes be made only by measurements of gas exchange or blood oxygen saturation or by invasive hemodynamic measurements during graded levels of exercise [see ACC/AHA Guidelines for Exercise Testing].

(2) With a syndrome of fluid retention. Patients may present with complaints of leg or abdominal swelling as their primary (or only) symptom. In these patients, the impairment of exercise tolerance may occur so gradually that it may not be noted unless the patient is questioned carefully and specifically about a change in activities of daily living.

(3) With no symptoms or symptoms of another cardiac or noncardiac disorder. During their evaluation for a disorder other than HF (e.g., an acute myocardial infarction, an arrhythmia, or a pulmonary or systemic thromboembolic event), these patients are found to have evidence of cardiac enlargement or dysfunction.

Most patients with HF should be routinely managed with a combination of 4 types of drugs: a diuretic, an ACE inhibitor, a beta-adrenergic blocker, and (usually) digitalis. The value of these drugs has been established by the results of numerous large-scale clinical trials, and the evidence supporting a central role for their use is compelling and persuasive. Patients with evidence of fluid retention should take a diuretic until a euvolemic state is achieved, and diuretic therapy should be continued to prevent the recurrence of fluid retention. Even if the patient has responded favorably to the diuretic, treatment with both an ACE inhibitor and a beta-blocker should be initiated and maintained in patients who can tolerate them, because they have been shown to favorably influence the long-term prognosis of HF. Therapy with digoxin may be initiated at any time to reduce symptoms and enhance exercise tolerance. Controlled clinical trials have shown some interventions to be useful in a limited cohort of patients with HF. Several of these agents like Aldosterone Antagonists, Angiotensin Receptor Blockers,Hydralazines and Isosorbide Dinitrates are undergoing active investigation in large scale trials to determine whether their role in the management of HF might be justifiably expanded. Several drugs like Nasopeptidase Inhibitors, Cytokine Antagonists and Endothelin Antagonists are under active evaluation in long-term large-scale trials because they showed promise in pilot studies that involved small numbers of patients. Until the results of definitive trials are available, none of these interventions can be recommended for use in patients with HF. Patients presenting to the emergency department (ED) with acutely decompensated heart failure (ADHF) pose a major health care problem. These patients are often hemodynamically unstable and have disabling symptoms of dyspnea secondary to pulmonary edema. Rapid application of effective interventions is frequently required to achieve clinical stability and avoid the need for mechanical ventilation. After evaluation and stabilization in the ED, most patients will require hospital admission, although a subset of low-risk patients may be appropriate for discharge home following a period of observation. The in-hospital mortality rate for ADHF is 5%— 8%.1,2 Patients with ADHF face a median 6-day duration of hospitalization and a rehospitalization rate over the next 6 months as high as 50%.1,2 ED visits and subsequent hospitalizations for ADHF continue to constitute a major public health burden, with hospitalizations for heart failure having increased from 577,000 in 1985 to 970,000 in 1998 in the United States. The major expenditure for heart failure care is on hospitalizations, with an estimated $23 billion spent on the inpatient management of ADHF. Advances in the understanding ofthe pathophysiology of ADHF and recent clinical trials have provided new insight into successful treatment strategies to reverse ADHF rapidly. The therapeutic goals in patients presenting with ADHF are to reverse acute hemodynamic abnormalities, rapidly relieve symptoms, and initiate treatments that will decrease disease progression and improve survival. In the past, ADHF was often viewed as merely a disorder of volume overload and low cardiac output. Focus on acute maximization of cardiac output led to therapies that increased mortality. Use of intravenous diuretics alone led to further increases in systemic vascular resistance and further deleterious neurohumoral activation. More recently, it has become apparent that in most cases ADHF/pulmonary edema is related to a marked increase in systemic vascular resistance superimposed on insufficient systolic and diastolic myocardial functional reserve. Therefore the emphasis in treating ADHF has shifted from diuretic monotherapy and/or intravenous inotropic agents to intravenous vasodilators. This more physiologic approach to ADHF has been shown to relieve symptoms more rapidly and reduce patient morbidity, and thus has the potential to help control rising health care costs by reducing admissions, length of stay, and rehospitalization. Treatment strategies are using Intravenous Loop Diuretics, Inotropic Agents, Intravenous Vasodilators, and Morphine sulfate. For many decades morphine has been a commonly used medication for treating ADHF in the emergency medicine setting. Morphine exerts effects that may be favorable in patients with ADHF. It reduces preload and to a lesser extent afterload (systemic vascular resistance) and heart rate. Morphine results in venodilation, decreases the sensation of dyspnea, and reduces sympathetic nervous system activation. These effects may result in a significant reduction of myo- cardial oxygen demand. Accordingly, the currently available therapies for HF have many undesired site effects and drawbacks which makes them less effective, cost intensive and inconvenient for the patients.

Thus, the technical problem underlying the present invention is to provide means and methods for treating or preventing more efficiently heart failure and multi-organ dysfunction syndrome, which often accompanies said heart failure. The solution to said technical problem is provided by the embodiments characterized in the claims.

Accordingly, the present invention relates to the use of an opioid receptor antagonist for the preparation of a pharmaceutical composition for treating or preventing heart failure in a human subject.

The term "opioid receptor antagonist" relates to compounds which are capable to block or even reverse the biological responses induced by the opioid receptor activity. The opioid receptor is activated by the opioid like substances of the body. The term "opioid like substances" and the term "opioids" are used interchangeable throughout the text. These opioid like substances are peptides which are capable of binding to the opioid receptors, e.g., the endorphins, endomorphins, enkephalines, dynorphins, and deltorphins, as well as nociceptine, β-casomorphin-5, morphiceptin, and dermorphin. The structure of said substances is well known in the art and described in detail in Meunier 1995, Nature 377, 532; Zadina, 1997, Nature 386, 499; Corbett, A.D.; Paterson, S.J.; Kosterlitz, H.W.; in: Herz, A. (Ed.) 1993, Opioids I, 645, Springer-Nerlag, Berlin, Heidelberg, New York.

The opioid like substances suppress pain and block tachycardia, hypertension, hyperthermia, mydriasis, hyperventilation, anxiety, coughing, dysuria, and urgent need to empty the bowels in emergency situation for the body. The activation ofthe opioid receptors can also be measured in vitro. Suitable assays are well known in the art and are described in detail by Dhawan et al. (Dhawan 1996, Pharmacol Rev 48: 567-592). A screening method for determining an opioid receptor antagonist, preferably, comprises the following steps: (a) contacting cells known to comprise a given opioid receptor, preferably mammalian cells, with an opioid known to activate the said receptor and a potential opioid receptor antagonist, and (b) determining the response of said cells upon administration ofthe potential opioid receptor antagonist whereby an antagonist prevents the biological response induced by the opioid. Preferred responses to be determined are described by Dhawan (loc. cit.) or other responses referred to above. The mammalian cells are more preferably cells of the nervous system, such as neurons, dendritic cells, or precursors thereof. Moreover, suitable mammalian cells may be obtained by genetically engineering cell lines, such as COS-7 cells or Neuro2a cells, with a vector allowing expression of the opioid receptor (Zaki 1996, Annu. Rev. Pharmacol. Toxicol. 36:379-401; Arvidsson 1995, J. Neuroscience 15: 3328-3341; Kieffer 1995, Cell Mol Neuro- biol 15: 615-635; Pan 2003, Methods Mol Med.84:3-16. Pan 2003, Methods Mol Med. 84:17-28). Alternatively, an opioid receptor antagonist can be determined by an assay comprising the steps of (a) contacting an opioid receptor, an opioid known to bind to said receptor and a potential opioid receptor antagonist and (b) determining competition between the opioid and said antagonist for receptor binding. For determination of the competition it is preferred that either the potential antagonist or the opioid will be linked to a detectable label, such as a radioisotope or a chromogenic chemical entity. Opioid receptor antagonists may be selected of a diversity of compounds consisting of different types of chemical entities. A first group of compounds interfere with binding of opioid like substances to their respective receptors. Such compounds comprise chemical entities which are capable of interacting with the ligand binding sites of the receptor but which do not activate the receptor. Such compounds may be peptides, peptide analogues, peptidomimetics, PNAs, nucleic acids, small organic molecules or antibodies exhibiting said properties. Peptid antagonist may be obtained by modifying the well known opioid peptide agonists by 2',6'-Dimethyl substitution of the Tyr(l) residue of the opioid agonist peptides and deletion of the positively charged N- terminal amino group or its replacement with a methyl group. This has been recently shown to represent a general structural modification to convert opioid peptide agonists into antagonists. This conversion requires the syntheses of opioid peptide analogues containing either 3- (2,6-dimethyl-4-hydroxyphenyl)propanoic acid (Dhp) or (2S)-2-methyl-3-(2,6-dimethyl-4- hydroxyphenyl)propanoic acid [(2S)-Mdp] in place of Tyr(l). Using this approach, delta-, kappa- and mu-selective opioid peptide agonist peptides can successfully be converted into corresponding delta-, kappa- and mϋ-selective antagonists, whereby receptor selectivity is maintained or even improved. Preferably, two (2S)-Mdp(l)-analogues of the delta-selective cyclic enkephalin analogue H-Tyr-c[D-Pen-Gly-Phe(pF)-Pen]-Phe-OH are potent and selective delta antagonists. Most successful is the development of kappa antagonists derived from dynorphin A (Dyn A), including the highly potent and selective kappa-antagonist [(2S)- Mdp(l)]Dyn A(1-11)-NH(2) (dynantin) and the enzymatically stable octapeptide analogue [(2S)-Mdp(l),MeArg(7),D-Leu(8)]Dyn A(l-8)-NH(2). The (2S)-Mdp(l)-analogues of dynorphin B and alpha-neoendorphin are also kappa antagonists. The Dhp(l)-analogues of the mϋ-selective cyclic enkephalin analogue H-Tyr-c[N(epsilon), N(beta)-carbonyl-D- Lys(2),Dap(5)]enkephalinamide and of endomorphin-2 are known to be moderately potent mϋ opioid antagonists (Schiller 2003, Life Sci. 73: 691-698). Specific peptide antagonist may be also obtained by way of molecular modelling. Appropriate computer programs can be used for the identification of interactive sites of a putative antagonist and the polypeptides of the invention by computer assistant searches for complementary structural motifs (Fassina 1994, Immunomethods 5:114-120). Further appropriate computer systems for the computer aided design of protein and peptides are described in the prior art, for example, in Berry 1994, Bio- chem. Soc. Trans. 22:1033-1036; Wodak 1987, Ann. N. Y. Acad. Sci. 501:1-13; Pabo 1986, Biochemistry 25:5987-5991. The results obtained from the above-described computer analysis can be used in combination with the method of the invention for, e.g., optimizing known antagonists or agonists. Appropriate peptidomimetics and other antagonists can also be identified by the synthesis of peptidomimetic combinatorial libraries through successive chemical modification and testing the resulting compounds, e.g., according to the methods described herein. Methods for the generation and use of peptidomimetic combinatorial libraries are described in the prior art, for example in Ostresh 1996, Methods in Enzymology 267:220-234 and Dorner 1996, Bioorg. Med. Chem. 4:709-715. Furthermore, the three-dimensional and/or crystallographic structure of said compounds and the polypeptides of the invention can be used for the design of peptidomimetic drugs (Rose 1996, Biochemistry 35:12933-12944; Rutenber 1996, Bioorg. Med. Chem. 4:1545-1558). It is very well known how to obtain said compounds, e.g. by chemical or biochemical standard techniques. Antibodies which are suitable as opioid receptor antagonists must specifically recognize an epitope of the receptor which allows upon binding of the antibody to block the binding of the opioid like substance which is the ligand of said receptor. The epitope-antibody complex may alternatively induce changes of the conformation ofthe receptor whereby the receptor is unable to bind its ligand in the induced conformation. Antibodies against such epitopes ofthe receptor can be prepared by well known methods using a (natural or synthetic) fragment comprising the said epitope derived from the receptor as an antigen. Monoclonal antibodies can be prepared, for example, by the techniques as originally described in Kδhler and Milstein 1975, Nature 256:495, and Galfre 1981, Meth. Enzymol. 73:3, which comprise the fusion of mouse myeloma cells to spleen cells derived from immunized mammals. In a preferred embodiment ofthe invention, said antibody is a monoclonal antibody, a polyclonal antibody, a single chain antibody, human or humanized antibody, primatized, chimerized or fragment thereof that specifically binds the epitope of the opioid receptor. Such fragments include bispecific antibody, synthetic antibody, antibody fragment, such as Fab, Fv or scFv fragments etc., or a chemically modified derivative of any of these. Furthermore, antibodies or fragments thereof to the aforementioned polypeptides can be obtained by using methods which are described, e.g., in Harlow and Lane 1988, Antibodies, A Laboratory Manual, CSH Press, Cold Spring Harbor. These antibodies can be used, for example, for the immunoprecipitation and immunolocaliza- tion ofthe variant polypeptides ofthe invention as well as for the monitoring ofthe presence of said variant polypeptides, for example, in recombinant organisms, and for the identification of compounds interacting with the proteins according to the invention. For example, surface plasmon resonance as employed in the BIAcore system can be used to increase the efficiency of phage antibodies which bind to an epitope of the protein of the invention (Schier 1996, Human Antibodies Hybridomas 7:97-105; Malmborg 1995, J. Immunol. Methods 183:7-13). Small organic molecules may be obtained by a screening method as referred to above. Preferably, compounds to be screened are those disclosed in Williams 2001, Physiol Rev 81: 299-343; Boehm 2002, Pharmacol Rev, 54: 43-99; Mogil 2001, Pharmacol Rev 53: 381-415, Bryant 1997, Biol Chem 378: 107-114; Temussi 1994, Biochem Biophys Res Commun 198: 933-939; and Zaki loc. cit. More preferably, the compounds are dike- topiperazines as disclosed in Bryant, loc. cit., or peptide derivatives comprising tetrahydro-3- isoquinoline carboxylic acid as disclosed in Temussi, loc. cit.. A second group of compounds interfere with the expression or translation of the opioid receptors. Such group comprises, e.g., RNAi molecules, antisense RNA, interfereing oligonucleotides or triple helix forming agents. Methods how to generate such molecules are well known in the art and are described in detail below. The structure for such molecules can be easily designed based on the sequence information available for the opioid receptors referred to in detail below. Preferably, the opioid receptor antagonist ofthe use of the present invention exerts its effects in the central nervous sytem. Thus, a preferred opioid receptor antagonist for treating heart failure must pass the blood brain barrier or must be a P-gylcoprotein (P-gp) substrate to exhibit its effects on the central nervous system. It is well known in the art how a compound must be designed to be capable of passing the blood brain barrier or must be a P-gp substrate (Adenot 2004, J Chem Inf Comput Sci. 44:239-48). The term "pharmaceutical composition" as used herein comprises the opioid receptor antagonists ofthe present invention and optionally one or more pharmaceutically acceptable carrier. The substances of the present invention may be formulated as pharmaceutically acceptable salts. Acceptable salts comprise acetate, methylester, HC1, sulfate, chloride and the like. The pharmaceutical compositions can be conveniently administered by any of the routes conventionally used for drug administration, for instance, orally, topically, parenterally or by inhalation. The substances may be administered in conventional dosage forms prepared by combining the drugs with standard pharmaceutical carriers according to conventional procedures. These procedures may involve mixing, granulating and compressing or dissolving the ingredients as appropriate to the desired preparation. It will be appreciated that the form and character of the pharmaceutically acceptable character or diluent is dictated by the amount of active ingredient with which it is to be combined, the route of administration and other well- known variables. The carrier(s) must be "acceptable" in the sense of being compatible with the other ingredients of the formulation and not deleterious to the recipient thereof. The pharmaceutical carrier employed may be, for example, either a solid or a liquid. Exemplary of solid carriers are lactose, terra alba, sucrose, talc, gelatin, agar, pectin, acacia, magnesium stearate, stearic acid and the like. Exemplary of liquid carriers are phosphate buffered saline solution, syrup, oil such as peanut oil and olive oil, water, emulsions, various types of wetting agents, sterile solutions and the like. Similarly, the carrier or diluent may include time delay material well known to the art, such as glyceryl mono-stearate or glyceryl distearate alone or with a wax. The substance according to the present invention can be administered in various manners to achieve the desired effect. Said substance can be administered either alone or in the formulated as pharmaceutical preparations to the subject being treated either orally, topically, parenterally or by inhalation. Moreover, the substance can be administered in combination with other substances either in a common pharmaceutical composition or as separated pharmaceutical compositions. The diluent is selected so as not to affect the biological activity of the combination. Examples of such diluents are distilled water, physiological saline, Ringer's solutions, dextrose solution, and Hank's solution. In addition, the pharmaceutical composition or formulation may also include other carriers, adjuvants, or nontoxic, nonthera- peutic, nonimmunogenic stabilizers and the like. A therapeutically effective dose refers to that amount of the substance according to the invention which ameliorate the symptoms or condition. Therapeutic efficacy and toxicity of such compounds can be determined by standard pharmaceutical procedures in cell cultures or experimental animals, e.g., ED50 (the dose therapeutically effective in 50%) of the population) and LD50 (the dose lethal to 50% of the population). The dose ratio between therapeutic and toxic effects is the therapeutic index, and it can be expressed as the ratio, LD50/ED50. The dosage regimen will be determined by the attending physician and other clinical factors; preferably in accordance with any one of the above described methods. As is well known in the medical arts, dosages for any one patient depends upon many factors, including the patient's size, body surface area, age, the particular compound to be administered, sex, time and route of administration, general health, and other drugs being administered concurrently. Progress can be monitored by periodic assessment. A typical dose can be, for example, in the range of 1 to 1000 μg; however, doses below or above this exemplary range are envisioned, especially considering the aforementioned factors. Generally, the regimen as a regular administration of the pharmaceutical composition should be in the range of 1 μg to 10 mg units per day. If the regimen is a continuous infusion, it should also be in the range of 1 μg to 10 mg units per kilogram of body weight per minute, respectively. Progress can be monitored by periodic assessment. However, depending on the subject and the mode of administration, the quantity of substance administration may vary over a wide range to provide from about 0.01 mg per kg body mass to about 10 mg per kg body mass, usually. The pharmaceutical compositions and formulations referred to herein are administered at least once in accordance with the use of the present invention. However, the said pharmaceutical compositions and formulations may be administered more than one time, for example from one to four times daily up to a non-limited number of days. Specific formulations of the substance according to the invention are prepared in a manner well known in the pharmaceutical art and usually comprise at least one active substance referred to herein above in admixture or otherwise associated with a pharmaceutically acceptable carrier or diluent thereof. For making those formulations the active substance(s) will usually be mixed with a carrier or diluted by a diluent, or enclosed or encapsulated in a capsule, sachet, cachet, paper or other suitable containers or vehicles. A carrier may be solid, semisolid, gel-based or liquid material which serves as a vehicle, excipient or medium for the active ingredients. Said suitable carriers comprise those mentioned above and others well known in the art, see, e.g., Remington's Pharmaceutical Sciences, Mack Publishing Company, Easton, Pennsylvania. The formulations can be adopted to the mode of administration comprising the forms of tablets, capsules, suppositories, solutions, suspensions or the like. The dosing recommendations will be indicated in product labeling by allowing the prescriber to anticipate dose adjustments depending on the considered patient group, with information that avoids prescribing the wrong drug to the wrong patients at the wrong dose.

The term "treating" as used herein means that the degree of severity ofthe symptoms accompanied by a disease is reduced, i.e. amelioration, or the symptoms are even absent by a significant number of subjects treated as described herein. A significant difference can be determined by standard statistical methods, such as Student's t-test, chi²-test or the U-test according to Mann and Whitney. Moreover, the person skilled in the art can adopt these and other statistical method known in the art individually without an undue burden. The term "preventing" as used herein means that symptoms accompanied by a disease do not or less often appear in subjects which have been subjected to the use of the invention while they will appear with a statistically higher frequency in subjects which have not been subjected to the use ofthe invention. A significant difference can be determined by standard statistical methods as described above.

The term "heart failure" as used in accordance with the present invention is well known in the art. Symptoms and clinical parameters have been described above. Specifically, the heart failure referred to in the context of the present invention is a disorder accompanied by structural damages of the myocardium, in particular on the level of the heart muscle cells. The term "heart failure" is clearly distinguishable for the skilled practitioner from a similar phenomenon, the myocardial stunning. The latter one is a reperfussion disorder (Bolli 1999, Physiological Rev 79: 609-635). Preferably, the heart failure is terminal heart failure accompanied by multi-organ dysfunction syndrome or is heart failure resulting from sepsis. Most preferably, the terminal heart failure is caused by Chagas disease. In another preferred embodiment of the use of the present invention, the patient to be treated suffering from heart failure is free of pain or has been treated with a selective μ (mil) agonist, preferably β-FNA, M-CAM, CTAP, CTOP, or Cyprodime.

Surprisingly, it has been found in accordance with the present invention that opioid receptor antagonists such as Naloxone or Naltrexone are suitable drugs to efficiently treat or prevent heart failure and diseases conditions accompanied therewith, such as multi-organ dysfunction syndrome. This finding is particularly a surprise because patients suffering from the aforementioned diseases, in principle, suffer from pain and need pain blocking drugs, i.e. opioid receptor agonists such as the opioids. Accordingly, administration of opioid receptor antagonists was thought to be contraindicative for such patients in the prior art (Crit Care Med 31: 1250-1256; Barr, Complications in Anesthesia, John L, Atlee, M.D., W.B. Saunders Com- pany, ISBN 0-7216-7161-6, Chapter 30, Reversal Agents: 114-116; Information onNaloxone by CuraMED Pharma GmbH 1999, drug approval number 6990.00.00).

The interpretation of the terms and the explanations made hereinabove and below apply mutatis mutandis for all embodiments described herein.

Moreover, encompassed by this is invention is the use of an opioid receptor antagonist for the preparation of a pharmaceutical composition for treating or preventing multi-organ dysfunction syndrome in a subject, most preferably a human subject.

The term "subject" as used in the sense of the present invention comprises animals and humans. Animals in accordance with the invention are, preferably, mammals, most preferably dogs, cats or horses.

The term "multi-organ dysfunction syndrome" refers to a disease condition in which the function of various organs of the body is impaired. The condition may comprise failures of the kidney, the liver, the gastrointestinal system, the nervous system, the cardiovascular system including the heart, the immune system, and the endocrine organs. The disease condition as referred to in accordance with the invention is preferably accompanied by the following disorders: (a) dysfunction of the unspecific immune system particular of the macrophages, and activation of the blood clotting cascade, the complement system and the kalikrein-kinin system, (b) failure ofthe cardio-vascular system, endothelial dysfunction, tissue ischemia, (c) impaired mucosal barrier function in the gut accompanied with invasion of bacteria or bacterial products into the lymphatic or blood circulation, (d) impaired cellular functions including signal transduction and stress gene expression. Further details are summarized in Rensing 2001, Anaesthesist 50: 819-841. Moreover, the term "multi-organ dysfunction syndrome" also includes sepsis -associated organ dysfunction. Sepsis and sepsis-associated syndrome are discussed in detail in Mitchell loc. cit.

As discussed for heart failure, surprisingly, it has been found that opioid receptor antagonist can effectively ameliorate, treat, and prevent the disease condition. Patients suffering from multi-organ dysfunction syndrome are usually also in need of pain blocking medicaments such as opioids. Therefore, administering a opioid receptor antagonist which infers with opioid signalling, is also, in principle, contraindicative for such patients. In a preferred embodiment of the use of the present invention said multi-organ dysfunction syndrome comprises paralytic ileus and/or kidney failure.

The symptoms of paralytic ileus and kidney failure are known to those skilled in the art and are described in detail in standard medical text books such as Stedman or Pschyrembel.

In a further preferred embodiment of the use of the present invention, said opioid antagonist is capable of binding to at least one opioid receptor having an amino acid sequence encoded by a polynucleotide selected from the group consisting of:

(a) a polynucleotide comprising the nucleic acid sequence as shown in SEQ ID NO:l (δ(delta)), SEQ ID NO:3 (κ(kappa)), SEQ ID NO:5, 7, 9, 11, or 13 (σ(sigma)) or encoding the ε(epsilon) opioid receptor;

(b) a polynucleotide encoding an amino acid sequence as shown in SEQ ID NO:2 (δ(delta)), SEQ ID NO:4 (κ(kappa)), SEQ ID NO:6, 8, 10, 12 or 14 (σ(sigma)) or the amino acid ofthe ε(epsilon) opioid receptor; and

(c) a polynucleotide which has a nucleic acid sequence being at least 70%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98% or at least 99% identical to the nucleic acid sequence ofthe polynucleotide of (a) or (b), whereby the opioid antagonist does not bind to the μ(mϋ) opioid receptor (SEQ ID NO: 9). The term "capable of binding to at least one opioid receptor" encompasses selective antagonists which solely bind to any one of the aforementioned opioid receptors and antagonists which bind to more than one of those receptors with different affinities. Whether an antagonist is capable of binding capable of binding to a receptor can be determined by standard techniques including those discussed in context with screening methods for antagonists above. The binding affinity for the opioid antagonist should be high enough to prevent receptor activation by the opioid ligands of the receptor in order to prevent activation when the receptor is exposed to both substances. Such binding affinities are preferably in the range of K; 1-lOOOnM, more preferably, 1-lOOnM, and most preferably 1-1 OnM. The binding of the antagonist to the receptor(s) shall be selective in that the antagonist must not bind to the μ(mϋ) opioid receptor (SEQ ID NO: 9) in a way as described before. Selectivity of binding is preferably 10 times, more preferably 100 times, most preferably 1000 times calculated as ratio of Ki value of the antagonist for the δ(delta), κ(kappa), σ(sigma) or ε(epsilon) opioid receptor to the K; value of the antagonist for the μ(mϋ) opioid receptor. Suitable assays for determing antagonist binding and for measuring the affinity of an antagonist are disclosed in Williams 2001, Physiol Rev 81: 299-343; Boehm 2002 Pharmacol Rev, 54: 43-99; Mogil 2001 Pharmacol Rev 53: 381-415 and references referred to therein.

The term "polynucleotide" relates to polynucleotides encoding a opioid receptor as specified above. The structure of polynucleotides encoding the opioid receptors is known in the art and shown, e.g., in SEQ ID NO:l (δ(delta) receptor), SEQ ID NO:3 (κ(kappa) receptor), SEQ ID NO:5, 7, 9, 11, or 13 (σ(sigmal-5) receptors). Moreover, polypeptides of the invention are those encoding the opioid receptors having an amino acid sequence as shown in SEQ ID NO:2 (δ(delta) receptor), SEQ ID NO:4 (κ(kappa) receptor), SEQ ID NO:6, 8, 10, 12 or 14 (σ(sigmal-5) receptor). The invention further encompasses polynucleotides which are capable to hybridize under stringent conditions to the polynucleotides having the aforementioned nucleic acid sequences or encoding polypetides having the aforementioned amino acid sequences. Such stringent conditions are hybridization in 300mM sodiumhydrogenphos- phate/dihydrogenphosphate, pH 6.8, 20% SDS, ImM EDTA for one hour at 68°C followed by three to five washing steps in 5mM sodiumhydrogenphosphate/dihydrogenphosphate, pH 6.8, 0.1% SDS, ImM EDTA for 30 minutes each step at 68°C. Said polynucleotides are most preferably at least 70%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%o, at least 98% or at least 99%) identical to the polynucleotides having the aforementioned nucleic acid sequences or encoding polypetides having the aforementioned amino acid sequences. Also encompassed by the polynucleotides referred to in connection with the present invention are biologically active fragments of the polynucleotides specified before. Said fragments may be obtained by deletion of one or more nucleotides of the respective nucleic acid sequences. The fragments can be generated by standard techniques well known to the person skilled in the art. Moreover, said fragments may be obtained as the result of naturally occurring alternative splicing of the opioid receptor mRNAs. The fragments referred to in accordance with the invention must comprise the binding or interaction sites for the opioid receptor antagonists. This interaction sites are known in the art or can be determined by standard techniques (Bryant loc. cit; Zaki loc. Cit).

Selective antagonists for some of the aforementioned opioid receptors are indicated in the following Table 1.

Table!: receptor δ(delta) κ(kappa) σ(sigma) selective BNTX: (E)-7- Nor-BNI: nor- 3-C4-chlorobenzvlV8- Benzylidenenaltrexone antagonist Binaltorphimine (^"llClmethoxv-1.2.3.4- DALCE: TD- tetrahvdro- Ala2,Leu5,Cys6]- GNTI: 5'- chromeno[3,41pvrifin-5- Enkephalin Guanidinylnaltrindole one Naltriben U-50488H 5'-NTII: Naltrindole 5'- Haloperidol isothiocyanate TIPPm: H-Tvr-Ticv- NE-100: N,N-dipropvl-2. [CH2NH]Phe-Phe-OH [4-methoxy-3-(2- Naltrindole phenylenoxy)-phenyl] - ethylamine monohydπ ICI- 174,864: N,N- Diallyl-Tyr-Aib-Aib- chloride Phe-Leu TIPP: H-Tyr-Tic-Phe- Metaphit Phe-OH Ibogaine

T+Vpentazocine

BMY 14802: a-(4^ Fluorophenyl)-4-(5- fluoro-2-pyrimidinyl)- 1 - piperazinebutanol hydro' chloride

IPAG: l-(4-Iodophenyl> 3-(2- adamantyl)guanidine,

4-PPBP maleate: - Phenyl-l-(4- phenylbutyl)piperidine maleate,

SM-21 maleate: (±)- Tropanyl 2-(4- chlorophenoxy)butanoate maleate,

Rimcazole dihvdrochlo- ride BW 234U: 9-[3-(cis- 3,5-Dimethyl-l- piperazinyl)propyl] -9H- carbazole dihydrochlo- ride,

BD 1063 dihvdrochlo- ride: l-[2-(3,4- Dichlorophenyl)ethyl] -4- methylpiperazine dihy- drochloride,

BD 1063 dihvdrochlo- ride: l-[2-(3,4- Dichlorophenyl)ethyl] -4- methylpiperazine dihy- drochloride

Thus, more preferably, the opioid antagonist of the embodiment describe before is BNTX: (E)-7-Benzylidenenaltrexone, DALCE: [D-Ala2,Leu5,Cys6]-Enkephalin, Naltriben, 5 '-NTH: Naltrindole 5'-isothiocyanate, TIPP(Ψ): H-Tyr-Ticψ-[CH2NH]Phe-Phe-OH, Naltrindole, ICI- 174,864: N,N-Diallyl-Tyr-Aib-Aib-Phe-Leu, TIPP: H-Tyr-Tic-Phe-Phe-OH specific for the δ(delta) opioid receptor or Nor-BNI: nor-Binaltorphimine, GNTI: 5'-Guanidinylnaltrindole, U-50488H specific for the κ(kappa) opioid receptor, or 3-(4-chlorobenzyl)-8-[l lC]methoxy- l,2,3,4-tetrahydrochromeno[3,4]pyrifιn-5-one, Haloperidol, NE-100: N,N-dipropyl-2-[4- methoxy-3-(2-phenylenoxy)-phenyl]-ethylamine monohydrochloride, Metaphit, Ibogaine, (+)-pentazocine, BMY 14802: a-(4-Fluorophenyl)-4-(5-fluoro-2-pyrimidinyl)-l- piperazinebutanol hydrochloride, IPAG: l-(4-Iodophenyl)-3-(2-adamantyl)guanidine, 4- PPBP maleate: 4-Phenyl-l-(4-phenylbutyl)piperidine maleate, SM-21 maleate: (±)-Tropanyl 2-(4-chlorophenoxy)butanoate maleate, Rimcazole dihydrochloride BW 234U: 9-[3-(cis-3,5- Dimethyl-l-piperazinyl)propyl]-9H-carbazole dihydrochloride, BD 1063 dihydrochloride: 1- [2-(3,4-Dichlorophenyl)ethyl]-4-methylpiperazine dihydrochloride, BD 1063 dihydrochloride: l-[2-(3,4-Dichlorophenyl)ethyl]-4-methylpiperazine dihydrochloride specific for the σ (sigma) receptor.

In another preferred embodiment, said opioid antagonist is Naloxone, Naltrexone, β- Chlornaltrexamine, Diprenorphine, β-Chlornaltrexamine, Methocinnamox, D-Phe-Cys-Tyr- D-Trp-Arg-Thr-Pen-Thr-NH₂, D-Phe-Cys-Tyr-D-Trp-Orn-Thr-Phe-Thr-NH₂, C prodime, SMS-201995, or CTP.

In another preferred embodiment of the use of this invention said opioid antagonist is a polynucleotide capable of interacting specifically with a polynucleotide as defined in any one of (a) to (c) referred to above and is selected from the group consisting of: RNAi molecules, antisense RNA molecules, oligonucleotides, and triple helix forming agents. The term "of interacting specifically with a polynucleotide" means that the polynucleotide interacts via hybridization, i.e. base pairing, to a polynucleotide having the complementary sequence thereto. A complete base pair match is preferred.

The term "RNAi molecules" refers to small interfering RNA molecules. Double-stranded RNA-mediated interference (RNAi) is a simple and rapid method of silencing gene expression in a range of organisms. The silencing of a gene is a consequence of degradation of RNA into short RNAs that activate ribonucleases to target homologous mRNA. The resulting phe- notypes either are identical to those of genetic null mutants or resemble an allelic series of mutants. Extensive genetic and biochemical analysis revealed a two-step mechanism of RNAi-induced gene silencing. The first step involves degradation of dsRNA into small inter- fering RNAs (siRNAs), 21 to 25 nucleotides long, by an RNase Ill-like activity. In the second step, the siRNAs join an RNase complex, RISC (RNA-induced silencing complex), which acts on the cognate mRNA and degrades it. Several key components such as Dicer, RNA- dependent RNA polymerase, helicases, and dsRNA endonucleases have been identified in different organisms for their roles in RNAi. Some of these components also control the development of many organisms by processing many noncoding RNAs, called micro-RNAs. The biogenesis and function of micro-RNAs resemble RNAi activities to a large extent. Recent studies indicate that in the context of RNAi, the genome also undergoes alterations in the form of DNA methylation, heterochromatin formation, and programmed DNA elimination. As a result of these changes, the silencing effect of gene functions is exercised as tightly as possible. Because of its exquisite specificity and efficiency, RNAi is being considered as an important tool not only for functional genomics, but also for gene-specific therapeutic activities that target the rnRNAs of disease-related genes (Agrawal 2003, Microbiol Mol Biol Rev. 67:657-85). The specificity is also achieved by selecting a fragment resembling a nucleic acid fragment of the polynucleotide encoding an opioid receptor. Such a fragment comprises at least 20, at least 100, at least 200, at least 500 or at least 1000 contiguous nucleotides of the full length opioid receptor sequence in length. By interfering with its expression as set forth above, RNAi molecules act as specific antagonists of opioid receptors. The term "antisense RNA molecules" refers to RNA which has the reverse complementary sequence to the messenger RNA encoding the opioid receptors referred to in accordance with the present invention. Accordingly, such an antisense RNA shall be capable of forming a double stranded RNA molecule with the messenger RNA via hybridization. The double stranded RNA molecule including the messenger RNA will be subsequently degraded in a cell. Thus, no opioid receptor proteins are produced. It might be sufficient to produce an antisense RNA which is reverse complementary merely to a fragment ofthe full length messenger RNA. Preferably, such a fragment comprises at least 50, at least 100, at least 200, at least 500 or at least 1000 contiguous nucleotides of the opioid receptor sequence in length. It is well known how antisense RNA can be manufactured. For instance, a polynucleotide encoding an opioid receptor could be introduced in a plasmid in reverse orientation with respect to a promoter element present in said plasmid. The promoter induces expression of an antisense RNA instead of the normal messenger RNA. Such a plasmid can be used for in vitro or in vivo transcription of RNA. The term "oligonucleotides" encompasses oligonucleotides which are complementary to a fragment ofthe nucleic acid sequence encoding the opioid receptors referred to in accordance with the present invention and chemically modified derivatives thereof. The oligonucleotides comprise at least 10, at least 15, at least 20 or at least 25 contiguous nucleic acids of the opioid receptor sequence in length. Chemical modifications for oligonucleotides are well known in the art. Upon administration ofthe oligonucleotide to the messenger RNA, a complex is formed which will be subsequently degraded in a cell. These modifications may increase the degradation of the complex of oligonucleotide and messenger RNA which forms upon administration ofthe oligonucleotide to the messenger RNA.

The term "triple helix forming agents" refers to oligonucleotides and polynucleotides which are capable of interacting with a DNA double strand resulting in formation of a triple helix. As for the other means interfering with opioid receptor expression, specificity can be achieved by using a triple helix forming polynucleotide which has a nucleic acid sequence complementary or identical to the target opioid receptor sequence specified above. Specific gene expression involves the binding of natural ligands to the DNA base pairs. Among the compounds rationally designed for artificial regulation of gene expression, oligonucleotides can bind with a high specificity of recognition to the major groove of double helical DNA by forming Hoogsteen type bonds with purine bases ofthe Watson-Crick base pairs, resulting in triple helix formation. Although the potential target sequences were originally restricted to polypurine-polypyrimidine sequences, considerable efforts were devoted to the extension of the repertoire by rational conception of appropriate derivatives. Efficient tools based on triple helices were developed for various biochemical applications such as the development of highly specific artificial nucleases. Recent developments in the area of triple helix technology have brought about new bases that specifically recognize pyrimidine-purine inversion sites as well as sugar modifications, for example, the 2'-aminoethoxy-oligonucleotides or oligonucleotides based on the locked nucleic acid sugar unit, which greatly enhance triplex stability and alleviate in part the sequence restriction constraints. With this, sequence-specific ge- nomic DNA manipulation is starting to become a useful tool in biotechnology (Praseuth 1999, Biochim Biophys Acta. 1489:181-206; Buchini 2003, Curr Opin Chem Biol. 7:717-26 and references cited therein).

The opioid receptor antagonist referred in accordance with the present invention may be administered in combination with one or more opioid agonists as long as theses agonists have positive myocardial influences. Accordingly, in a further embodiment any one of the aforementioned κ(kappa) opioid receptor antagonists may be administered in combination with an agonist, preferably, a δ(delta) opioid receptor agonist. Most preferably, said agonist is selected from the group consisting of: [DPDPE: [D-Pen2,5]-Enkephalin, (-)-TAN-67: (-)-2- Methyl-4aα-(3-hydroxyphenyl)-l,2,3,4,4a,5,12,12aα-octahydroquinolino[2,3,3-g]isoqui- noline, [D-Ala2,Glu4]-Deltrophin, DSLET: [D-Ser2,Leu5,Thr6]-Enkephalin, BW373U86: (±)-(l[S*]2α,5β)-4-([2,5-Dimethyl-4-(2-ρropenyl)-l-piperazinyl][3-hydroxyphenyl]methyl)- N,N-diethylbenzamide], and SNC80: (+)-4-[(αR)-α-((2S,5R)-4-allyl-2,5-dimethyl-l- piperazinyl)-3-methoxybenzyl]-N,N-diethylbenzamide. The antagonist and agonist may be administered to the subject simultaneously or sequentially. For simultaneous administration, the compounds may be mixed prior to administration and the mixture comprising both compounds is to be administered. Said mixture may also comprise further drugs such as antibiotics, or pain-blocking agents.

Moreover, the invention relates to a method for treating a human subject suffering from heart failure comprising the step of inhibiting opioid receptor signalling by administering to said subject an opioid receptor antagonist in a therapeutically effective dosage.

Furthermore, the invention encompasses a method for treating a subject suffering from multi- organ dysfunction syndrome comprising the step of inhibiting opioid receptor signalling by administering to said subject an opioid receptor antagonist in a therapeutically effective dosage.

In a preferred embodiment of the method ofthe invention, said multi-organ dysfunction syndrome comprises paralytic ileus and/or kidney failure.

In a more preferred embodiment of the method of the invention, the opioid receptor antagonist is administered in combination with an opioid receptor agonist having positive myocardial influence, preferably a δ (delta) opioid receptor agonist as specified above.

Moreover, the preferred embodiments of the uses of the present invention apply mutatis mutandis for the methods ofthe invention. The disclosure content of each document cited herein (including any manufacturer's specifications, instructions, etc.) is hereby incorporated by reference.

The figure shows a schematic drawing of an opioid receptor.

Claims

Claims

1. Use of an opioid receptor antagonist for the preparation of a pharmaceutical composition for treating or preventing heart failure in a human subject.

2. Use of an opioid receptor antagonist for the preparation of a pharmaceutical composition for treating or preventing multi-organ dysfunction syndrome in a subject.

3. The use of claim 2, wherein said multi-organ dysfunction syndrome comprises paralytic ileus and/or kidney failure.

4. The use of claim 2 or 3, wherein said subject is human.

5. The use of any one of claims 1 to 4, wherein said opioid antagonist is capable of binding to at least one opioid receptor having an amino acid sequence encoded by a polynucleotide selected from the group consisting of: (a) a polynucleotide comprising the nucleic acid sequence as shown in SEQ ID NO:l (δ(delta)), SEQ ID NO:3 (κ(kappa)), SEQ ID NO:5, 7, 9, 11 or 13 (σ(sigma)) or encoding the ε(epsilon) opioid receptor; (b) a polynucleotide encoding an amino acid sequence as shown in SEQ ID NO:2 (δ(delta)), SEQ ID NO:4 (κ(kappa)), SEQ ID NO:6, 8, 10, 12 or 14 (σ(sigma)) or the amino acid sequence ofthe ε(epsilon) opioid receptor; and (c) a polynucleotide which has a nucleic acid sequence being at least 70%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98% or at least 99% identical to the nucleic acid sequence of the polynucleotide of (a) or (b), whereby the opioid antagonist does not bind to the μ(mϋ) opioid receptor (SEQ ID NO: 15).

6. The use of claim 5, wherein said opioid receptor antagonist is BNTX: (E)-7- Benzylidenenaltrexone, DALCE: [D-Ala2,Leu5,Cys6]-Enkephalin, Naltriben, 5'- NTII: Naltrindole 5'-isothiocyanate, TIPP(Ψ): H-Tyr-Ticψ-[CH2NH]Phe-Phe-OH, Naltrindole, ICI-174,864: N,N-Diallyl-Tyr-Aib-Aib-Phe-Leu, TIPP: H-Tyr-Tic-Phe- Phe-OH specific for the δ(delta) opioid receptor or Nor-BNI: nor-Binaltorphimine, GNTI: 5'-Guanidinylnaltrindole, U-50488H specific for the κ(kappa) opioid receptor, or 3-(4-chlorobenzyl)-8-[l lC]methoxy-l,2,3,4-tetrahydrochromeno[3,4]pyrifin-5- one, Haloperidol, NE-100: N,N-dipropyl-2-[4-methoxy-3-(2-phenylenoxy)-phenyl]- ethylamine monohydrochloride, Metaphit, Ibogaine, (+)-pentazocine, BMY 14802: a- (4-Fluorophenyl)-4-(5-fluoro-2-pyrimidinyl)-l-piperazinebutanol hydrochloride, IPAG: l-(4-Iodophenyl)-3-(2-adamantyl)guanidine, 4-PPBP maleate: 4-Phenyl-l-(4- phenylbutyl)piperidine maleate, SM-21 maleate: (±)-Tropanyl 2-(4- chlorophenoxy)butanoate maleate, Rimcazole dihydrochloride BW 234U: 9-[3-(cw- 3,5-Dimethyl-l-piperazinyl)propyl]-9H-carbazole dihydrochloride, BD 1063 dihydrochloride: l-[2-(3,4-Dichlorophenyl)ethyl]-4-methylpiperazine dihydrochloride, BD 1063 dihydrochloride: l-[2-(3,4-Dichlorophenyl)ethyl]-4-methylpiperazine dihydrochloride specific for the σ (sigma) receptor.

7. The use of any one of claims 1 to 4, wherein said opioid antagonist is Naloxone, Naltrexone, nor-Binaltorphimine, U-50,488Η, β-Chlornaltrexamine, Diprenorphine, β-Chlornaltrexamine, Methocinnamox, D-Phe-Cys-Tyr-D-Trp-Arg-Thr-Pen-Thr-NH , D-Phe-Cys-Tyr-D-Trp-Orn-Thr-Phe-Thr-NH₂, Cyprodime, SMS-201995, or CTP.

8. The use of any one of the claims 1 to 4, wherein said opioid antagonist is a polynucleotide capable of interacting specifically with the polynucleotide as defined in any one of (a) to (c) of claim 5 and is selected from the group consisting of: RNAi molecules, antisense RNA molecules, oligonucleotides, and triple helix forming agents.

9. Use as described in any one of claims 1 to 8, wherein said opioid antagonist is to be administered in combination with an opioid agonist having positive myocardial influence.

10. The use of claim 9, wherein said agonist is a δ (delta) opioid receptor (SEQ ID NO: 2) agonist.

11. The use of claim 10, wherein said agonist is selected from the group consisting of: [DPDPE: [D-Pen2,5]-Enkephalin, (-)-TAN-67: (-)-2-Methyl-4aα-(3-hydroxyphenyl)- l,2,3,4,4a,5,12,12aα-octahydroquinolino[2,3,3-g]isoqui-noline, [D-Ala2,Glu4]- Deltrophin, DSLET: [D-Ser2,Leu5,Thr6]-Enkephalin, BW373U86: (±)-(l [S*]2α,5β 4-([2,5-Dimethyl-4-(2-propenyl)-l-piperazinyl][3-hydroxyphenyl]methyl)-N,N- diethylbenzamide], and SNC80: (+)-4-[(αR)-α-((2S,5R)-4-allyl-2,5-dimethyl-l- piperazinyl)-3 -methoxybenzyl] -N,N-diethylbenzamide

12. Method for treating a human subject suffering from heart failure comprising the step of inhibiting opioid receptor signalling by administering to said subject an opioid receptor antagonist in a therapeutically effective dosage.

13. Method for treating a subject suffering from multi-organ dysfunction syndrome comprising the step of inhibiting opioid receptor signalling by administering to said subject an opioid receptor antagonist in a therapeutically effective dosage.

14. The method of claim 10, wherein said multi-organ dysfunction syndrome comprises paralytic ileus and/or kidney failure.

15. The method of any one of claims 12 to 14, wherein the opioid receptor antagonist is administered in combination with an opioid receptor agonist having positive myocardial influence.