WO2017211780A1

WO2017211780A1 - Kaempferol for the treatment of cardiac diseases

Info

Publication number: WO2017211780A1
Application number: PCT/EP2017/063647
Authority: WO
Inventors: Johann SCHREDELSEKER; Fabiola WILTING; Maria DREXLER
Original assignee: Ludwig-Maximilians-Universitaet Muenchen
Priority date: 2016-06-06
Filing date: 2017-06-06
Publication date: 2017-12-14

Abstract

The present invention relates to the field of pharmaceutics and treatment of cardiac diseases. Specifically, the present invention provides activators of the mitochondrial calcium uniporter (MCU), in particular Kaempferol and its derivatives, for use in treatment of various cardiac diseases. Further provided herein are pharmaceutical compositions and kits that are useful for treating cardiac diseases.

Description

KAEMPFEROL FOR THE TREATMENT OF CARDIAC

DISEASES

BACKGROUND

[1] Cardiovascular diseases (CVDs) are a group of disorders of the heart and blood vessels that account for millions of deaths worldwide per year and cause significant costs to the healthcare system. In Germany alone, cardiovascular diseases caused the death of 350,000 people and lead to hospital costs in the amount of 37 billion Euros.

[2] Although the death rates of cardiovascular diseases in general have decreased due to better supply in recent years, morbidity and death rates due to cardiac arrhythmia and congestive heart failure is still increasing. The new German Heart Report of the German Society of Cardiology in 2014 estimated the death rate for cardiac arrhythmias to be 28.9 per 100,000 people and for heart failure to be 55.5 per 100,000 people, wherein approximately half of all heart failure patients die due to cardiac arrhythmia.

[3] The main reason for this alarming state is that the drugs currently available for the treatment of cardiac arrhythmia, i.e. antiarrhythmics, are extremely problematic in their application due to significant side effects. With the exception of beta-blockers, all antiarrhythmics have pro-arrhythmic side-effects and therefore cannot be administered in the long-term. Beta blockers are however ineffective for treatment of many types of arrhythmia and limit the patient's physical activity. Major reasons for the severe side effects of antiarrhythmic drugs are their pharmacological target structures, which, throughout, are ion channels in the cell membrane of heart cells. By blocking these channels, transmission of the arrhythmic signal in heart tissue should be inhibited and thus suppressed. However, inhibiting these channels, which are essential for stimulus transmission, also leads to an impairment of systolic depolarizing stimulus and thus promotes development of arrhythmia. [4] For treatment of congestive heart failure, medications to lower blood pressure, such as ACE inhibitors and diuretics are commonly used in order to reduce preload and afterload on the damaged heart. A heart-specific treatment is only possible by using cardiac glycosides. However, due to their strong pro-arrhythmic side effects in conjunction with a very narrow therapeutic index, these medicaments can only be used under observation in a hospital. [5] There is thus a need in the art to explore new substances and drug targets that overcome the disadvantages set out above.

SUMMARY

[6] The present invention provides kaempferol or a kaempferol derivative for use in a method of treatment of a cardiac disease in a subject, wherein the cardiac disease can preferably be prevented, attenuated or alleviated by activating mitochondrial calcium uniporter (MCU). The cardiac disease is preferably selected from arrhythmia, in particular tachycardia such as atrial, supraventricular or ventricular tachycardia, or congestive heart failure. [7] Further provided herein is a pharmaceutical composition comprising kaempferol or a kaempferol derivative for use in the treatment of a cardiac disease as described herein. A kit comprising Kaempferol or a Kaempferol derivative or a pharmaceutical composition comprising the same; and at least one active agent useful for treatment of said cardiac disease is also provided herein. [8] Kaempferol or the Kaempferol derivative used according to the invention is envisaged to be of the following general formula (I):

(I) wherein -i , R₂, ₃, and R₄ are identical or different and independently selected from hydrogen, alkyl, acyl, aliphatic acyl, araliphatic or aromatic acyl group or a sugar or sugar acid; or a pharmaceutically acceptable salt thereof. Exemplary Kaempferol derivatives envisioned for the use according to the invention include Astragalin, Kaempferol 3-0- neohesperidoside, Kaempferitrin, Tiliroside, Robinin, and Afzelin.

In a further aspect, the present invention also relates to a method for the treatment or prevention of a cardiac disease, wherein the cardiac disease can preferably be prevented, attenuated or alleviated by activating mitochondrial calcium uniporter (MCU), comprising administering a MCU activator, preferably kaempferol or a kaempferol derivative, to a subject in need thereof.

DESCRIPTION OF THE FIGURES

[9] Figure 1 : Kaempferol amplifies the transfer of Calcium from the sarcoplasmic reticulum into mitochondria. Mitochondrial calcium was measured in cultured cardiomyocytes (cell line HL-1 ) via the mitochondrial calcium indicator rhod-2 (A, black line; B, dark bars). After inducing release of calcium from the sarcoplasmic reticulum by administering of caffeine, an increase in mitochondrial calcium was observed, and was enhanced by Kaempferol in a dose-dependent manner. MCU blocker RuR suppressed this effect (A, gray line; B, light bars), proving a specific effect of Kaempferol on MCU.

[10] Figure 2: Kaempferol suppresses arrhythmogenic signals in heart muscle cells.

Calcium measurements in freshly isolated cells from a mouse model of catecholamine- induced polymorphic ventricular tachycardia, a calcium-induced cardiac arrhythmia, indicated that the catecholamine isoproterenol triggers an increased spontaneous calcium release in these cells in the diastolic phase after electrical stimulation with 0.5 Hz. Treatment of these cells with Kaempferol suppressed these spontaneous signals which can lead to cardiac arrhythmias in the healthy heart.

[11] Figure 3: Kaempferol suppresses ventricular fibrillation in mice. In a mouse model for catecholamine-induced polymorphic ventricular tachycardia, a calcium-induced cardiac arrhythmia, administration of epinephrine/caffeine resulted in bidirectional ventricular fibrillation (B). Administration of Kaempferol did not influence parameters of the ECG (A); but resulted in significant suppression of ventricular fibrillation (B).

[12] Figure 4: Kaempferol suppresses arrhythmogenic calcium signals in human iPSC cardiomyocytes. In cardiomyocytes differentiated from human induced pluripotent stem cells (IPSCs) from a CPVT patient and a healthy control, Kaempferol suppressed spontaneous diastolic calcium waves.

[13] Figure 5: Kaempferol reinforces calcium release into cardiomyocytes. In murine electrically stimulated cardiomyocytes, Kaempferol treatment results in an increased systolic calcium release (amplitude). Furthermore, release (time to peak) and inactivation (tau decay) of systolic calcium release were significantly accelerated.

[14] Figure 6: Kaempferol reinforces the contractile force in failing heart tissue.

Kaempferol effected an increase in contractile force in organotypic heart sections obtained from mice having developed congestive heart failure after transverse aortic constriction. Kaempferol (or DMSO as a vehicle) were added after 15 min (grey arrow) to the organ bath.

[15] Figure 7: Kaempferol reinforces the contractile force and accelerates relaxation velocity in failing heart tissue. Kaempferol effected an increase in contractile force and acceleration of relaxation in organotypic heart sections obtained from mice having developed congestive heart failure after transverse aortic constriction. Kaempferol (or DMSO as a vehicle) were added after 15 min (grey arrow) to the organ bath.

DETAILED DESCRIPTION

[16] The inventors of the present application have surprisingly found out that the mitochondrial calcium uniporter (MCU) is a potential target molecule for the treatment of several cardiac diseases. MCU is an intracellular calcium channel located in the inner membrane of the mitochondrion. Without wishing to be bound to theory it is believed targeting a protein other than a receptor on the cellular membrane will at most marginally influence the action potential of a heart muscle cell. It is thus assumed that targeting MCU will only have a small or no impact on transmission of electric stimuli in the heart. Therefore, it is believed that pro-arrhythmic side effects can be significantly reduced when treating a patient with a compound that targets MCU as compared to using a conventional drug such as, for example, a class I or III antiarrhythmic agent.

[17] The "mitochondrial calcium uniporter" or "MCU" as used herein is a transmembrane protein that allows the passage of calcium ions from a cell's cytosol into mitochondria. It is one of the primary sources of mitochondria uptake of calcium, and is dependent on membrane potential of the inner mitochondrial membrane and the concentration of calcium in the cytosol relative to the concentration in the mitochondria. MCU is known to be present in several species, including, for example, human, mouse, rat, bovine, or zebrafish, just no name a few. A human MCU is the protein of the UniProt accession number Q8NE86 (version 1 of 1 October 2002).

[18] A compound that targets MCU may for example be a compound that is an activator of MCU. An "activator of MCU" as used herein may be a compound that increases the biological activity of MCU, such as increasing the rate of mitochondrial uptake of calcium by MCU, e.g. by binding to the mitochondrial calcium uniporter complex, such as by binding to MCU. Such an activator for MCU can for example be a flavonoid. In particular, such an activator of MCU may be kaempferol or a kaempferol derivative. [19] The present invention thus envisions kaempferol or a kaempferol derivative for use in a method of treatment of a cardiac disease in a subject. It is understood that such a cardiac disease can be alleviated by activating mitochondrial calcium uniporter (MCU).

[20] The term "treatment" in all its grammatical forms includes therapeutic or prophylactic treatment of a subject in need thereof. A "therapeutic or prophylactic treatment" comprises prophylactic treatments aimed at the complete prevention of clinical and/or pathological manifestations or therapeutic treatment aimed at amelioration or remission of clinical and/or pathological manifestations. The term "treatment" thus also includes the amelioration or prevention of diseases. [21] A "cardiac disease" as used herein refers to a disease that affects the heart. The term "cardiac disease" generally includes heart arrhythmia, congestive heart failure, coronary artery diseases (CAD) such as angina and myocardial, hypertensive heart disease, rheumatic heart disease, cardiomyopathy, congenital heart disease, valvular heart disease, or carditis. [22] In the context of the invention, the cardiac disease may preferably be arrhythmia. As used herein, "arrhythmia", "heart arrhythmia" or "cardiac arrhythmia", which are used synonymously and interchangeably herein, refer to an irregular heartbeat, being either too fast or too slow. A heartbeat may be considered to be too fast if it is above 100 beats per minute in a human adult in resting state whereas a heartbeat may be considered to be too slow if it is below 60 beats per minute in a human adult in resting state. Sick sinus syndrome (also referred to as sinus dysfunction (SND), or sinoatrial node disease), a group of abnormal heart rhythms (arrhythmias) caused by a malfunction of the sinus node, is not envisioned for treatment according to the diseases and is thus preferably excluded from the scope of the invention. [23] The invention envisions that preferred arrhythmias to be treated include tachycardia. As used herein, the term "tachycardia" generally refers to any fast abnormal rhythm of the heart. In general, a resting heart rate over 100 beats per minute is accepted as tachycardia in human in adults. However, heart rates above the resting rate may be normal (such as with exercise) or abnormal (such as with electrical problems within the heart). However, heart rate should be considered in the context of the prevailing clinical picture. For example: in sepsis >90 bp may be considered tachycardia. Tachycardia specifically includes sinus tachycardia, atrial tachycardia, ventricular tachycardia or supraventricular tachycardia. As used herein, "sinus tachycardia" refers to a sinus rhythm with an elevated rate of impulses. As used herein, "atrial tachycardia" refers to a type of atrial arrhythmia in which the heart's electrical impulse comes from ectopic atrial pacemaker, that is to say an abnormal site in the upper chambers of the heart or atria, rather than from the SA node which is the normal site of origin of the heart's electrical activity. As used herein, "ventricular tachycardia" refers to a type of tachycardia, or a rapid heartbeat that arises from improper electrical activity of the heart presenting as a rapid heart rhythm, that starts in the ventricles. As used herein, "supraventricular tachycardia" refers to an abnormally elevated heart rhythm arising from improper electrical activity of the heart, which originates at or above the atrioventricular node.

[24] The invention envisions that preferred arrhythmias to be treated include atrial arrhythmia, ventricular arrhythmia, or supraventricular arrhythmia. An "atrial arrhythmia" as used herein refers to an arrhythmia originating from the atria. It may include premature atrial contractions, wandering atrial pacemaker, atrial tachycardia, atrial flutter and atrial fibrillation. A "ventricular arrhythmia" as used herein refers to an arrhythmia originating from the ventricle. It may include premature ventricular contractions, accelerated idioventricular rhythms, ventricular tachycardia or ventricular fibrillation. A "supraventricular arrhythmia" as used herein refers to an arrhythmia originating from the areas above the ventricle. It may include supraventricular tachycardia or paroxysmal supraventricular tachycardia, atrial fibrillation, Wolff-Parkinson-White syndrome, atrial flutter, or premature atrial contractions.

[25] A preferred arrhythmia to be treated according to the invention is a calcium-induced arrhythmia, such as catecholaminergic polymorphic ventricular tachycardia (CPVT), also called familial polymorphic ventricular tachycardia (FPVT) or catecholamine-induced polymorphic ventricular tachycardia. It is an inherited disorder in individuals with structurally- normal hearts. CPVT is due to a mutation in a gene encoding a calcium channel or proteins related to this channel. All mutated proteins participate in the regulation of calcium ion flow in and out of the sarcoplasmatic reticulum of cardiac cells. CPVT is characterized by stress- induced ventricular tachycardia. In subjects with CPVT, physical exertion and/or stress may induce bidirectional and/or polymorphic ventricular tachycardia that may lead to sudden cardiac death in the absence of detectable structural heart disease.

[26] In the context of the invention, the cardiac disease may also preferably be congestive heart failure. "Congestive heart failure" or "heart failure", as used herein refers to a state where the heart is unable to pump sufficiently to maintain blood flow to meet the body's needs. In the context of the invention, "congestive heart failure" may refer to a state, in which the heart is still able to pump blood, which may however be insufficient. A state in which the heart is not able to pump blood at all may be excluded from the meaning of "congestive heart failure" or "heart failure" in the context of the invention.

[27] Heart failure or congestive heart failure may include a systolic dysfunction or a diastolic dysfunction. A "diastolic dysfunction" as used herein generally refers to a backward failure of the ventricle to adequately relax and typically denotes a stiffer ventricular wall. This may cause inadequate filling of the ventricle, and therefore may result in an inadequate stroke volume. A "systolic dysfunction" as used herein, generally refers to a failure of the pump function of the heart, such as an insufficient contraction. It may be characterized by a decreased ejection fraction. The strength of ventricular contraction may be attenuated and inadequate for creating an adequate stroke volume, which may result in inadequate cardiac output. In general, a systolic dysfunction may be caused by dysfunction or destruction of cardiac myocytes or their molecular components. It is envisioned that systolic dysfunction may be a preferred condition to be treated according to the invention. [28] The state of heart failure or congestive heart failure may further be functionally classified. The New York Heart Association functional classification provides an established way of classifying the extent of congestive heart failure (The Criteria Committee of the New York Heart Association. (1994). Nomenclature and Criteria for Diagnosis of Diseases of the Heart and Great Vessels. (9th ed.). Boston: Little, Brown & Co. pp. 253-256.;. It places patients in one of four categories based on how much they are limited during physical activity; the limitations/symptoms are in regard to normal breathing and varying degrees in shortness of breath and/or angina pain. The classes (l-IV) are defined as follows:

[29] Class I: Cardiac disease, but no symptoms and no limitation in ordinary physical activity, e.g. no shortness of breath when walking, climbing stairs etc. [30] Class II: Mild symptoms (mild shortness of breath and/or angina) and slight limitation during ordinary activity.

[31] Class III: Marked limitation in activity due to symptoms, even during less-than- ordinary activity, e.g. walking short distances (20-100 m). Comfortable only at rest.

[32] Class IV: Severe limitations. Experiences symptoms even while at rest. Mostly bedbound patients.

[33] It is envisioned by the present invention that heart failure or congestive heart failure to be treated is preferably a heart failure or congestive heart failure selected from the group consisting of class I, class II, class III, and class IV according to the New York Heart Association Functional Classification. Preferably, the heart failure is selected from the group consisting of class I, class II, and class III heart failure according to the New York Heart Association Functional Classification. Preferably the heart failure is class I or class II heart failure according to the New York Heart Association Functional Classification. Preferably, the heart failure is class I heart failure according to the New York Heart Association Functional Classification. It is further envisioned by the present invention that the heart failure to be treated may be selected from the group consisting of left-sided heart failure, including heart failure with reduced ejection fraction or systolic heart failure and heart failure with preserved ejection fraction or diastolic heart failure, right-sided heart failure, biventricular heart failure, congestive heart failure, acute heart failure, chronic heart failure, and acute decompensated heart failure.

[34] It is envisioned by the invention that the "subject" or "patient", which is used synonymously and interchangeably throughout the application, may be an animal, preferably a vertebrate, preferably a mammal. Preferred subjects include human, mouse, rat, rabbit, hamster, pig, dog, cat, cattle, sheep, goat, camel, monkey, or ape. It is envisioned by the invention that a human may be most preferred.

Kaempferol and derivatives thereof

[35] As set out previously herein, the present inventors surprisingly identified Kaempferol as a promising agent for treatment of various cardiac diseases. Kaempferol is commonly known for its anti-cancer properties and has also been shown to have an array of antioxidant effects in vitro and in vivo. However, its beneficial effects in treatment of various cardiac diseases that can be alleviated by activating mitochondrial calcium uniporter (MCU) was unexpected.

[36] "Kaempferol" (lUPAC name: 3,5,7-trihydroxy-2-(4-hydroxyphenyl)chromen-4-one; PubChem CID 5280863 (Modify date: 2016-04-30)) is also known as Kempferol, obigenin, Rhamnolutein or Kaempherol and is a flavonol naturally occurring as a secondary metabolite in a variety of plants. It has the following general formula (II):

that is commercially available from various suppliers, e.g. Sigma-Aldrich Germany, product number 60010 (web catalogue of 31 May 2016), or can be prepared using methods well- known in the art. "Kaempferol derivatives" are also envisaged for the uses of the present invention; i.e. compounds structurally related to, and derivable from, Kaempferol, such as salts, esters, and the like. Kaempferol derivatives include chemical modifications, for instance different or additional side groups. The derivatives intended for the use according to the present invention are preferably pharmaceutically acceptable, i.e. capable of eliciting the desired therapeutic effect without causing any undesirable local or systemic effects in the recipient, and have the following general formula (I)

(I) wherein R-i , R₂, R₃, and R₄ are identical or different and independently selected from hydrogen, alkyl, acyl, or a sugar or sugar acid.

[37] As used herein, the term "alkyl" refers to a straight-chain, or branched alkyl group having 1 to 8 carbon atoms, preferably from 1 to 6, with 1 to 4 more preferred. Exemplary alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isoamyl, neopentyl, 1 -ethylpropyl, 3-methylpentyl, 2,2-dimethylbutyl, 2,3- dimethylbutyl, hexyl, octyl, etc. The alkyl moiety of alkyl-containing groups, such as alkoxy, alkoxycarbonyl, and alkylaminocarbonyl groups, has the same meaning as alkyl defined above. Lower alkyl groups, which are preferred, are alkyl groups as defined above which contain 1 to 4 carbons. A designation such as "C1 -C4 alkyl" refers to an alkyl radical containing from 1 to 4 carbon atoms. Alkyl groups may be optionally substituted.

[38] As used herein, the term "acyl" refers to a group of the formula R₅CO-, wherein R₅ is H or substituted or unsubstituted alkyl as defined above ("aliphatic acyl") or substituted or unsubstituted cycloalkyl ("aromatic acyl"), i.e. a saturated or partially saturated mono- or bicyclic alkyl ring system containing 3 to 10 carbon atoms, examples of which include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl and cyclooctyl.

[39] As used herein, the term "sugar" refers to known saccharides, such as sucrose (saccharose), glucose, fructose, maltose, lactose, rhamnose, arabinose, neohesperidose galactose, or robinose; or di- or oligosaccharides thereof. [40] As used herein, the term "sugar acid" refers to saccharides with a carboxyl group and includes, for instance, glyceric acid, xylonic acid, gluconic acid, ascorbic acid, glucuronic acid, iduronic acid, galacturonic acid, tartaric acid, mucic acid, or saccharic acid. [41] The skilled person will readily be able to select suitable Kaempferol derivatives based on their ability to activate the MCU as ascertainable using routine experiments as shown in the appended examples. The selected Kaempferol derivative will further preferably be pharmaceutically acceptable and elicit the desired therapeutic effect described elsewhere herein.

[42] Exemplary Kaempferol derivatives that are contemplated for the use according to the invention include:

[43] Astragalin (lUPAC name: 5,7-dihydroxy-2-(4-hydroxyphenyl)-3-[(2S_!3R_!4S_!5S,6R)- 3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxychromen-4-one; PubChem CID: 5282102 (Modify date: 2016-04-30)) also referred to as Kaempferol 3-O-glucoside;

[44] Kaempferol 3-O-neohesperidoside (lUPAC name: 3-[(2S,3R_!4S_!5S_!6R)-4,5- dihydroxy-6-(hydroxymethyl)-3-[(2R,3S_!4S_!5S_!6R)-3_!4,5-trihydroxy-6-methyloxan-2- yl]oxyoxan-2-yl]oxy-5,7-dihydroxy-2-(4-hydroxyphenyl)chromen-4-one; PubChem CID: 44575467 (Modify date: 2016-04-30)); [45] Kaempferitrin (lUPAC name: 5-hydroxy-2-(4-hydroxyphenyl)-3,7- bis[[(2S,3R,4R,5R,6S)-3,4,5-trihydroxy-6-methyloxan-2-yl]oxy]chromen-4-one; PubChem CID: 5486199 (Modify date: 2016-04-30)), also referred to as Lespenephril or Kaempferol- dirhamnoside;

[46] Tiliroside (lUPAC name: [(2R,3S_!4S_!5R_!6S)-6-[5,7-dihydroxy-2-(4-hydroxyphenyl)-4- oxochromen-3-yl]oxy-3,4,5-trihydroxyoxan-2-yl]methyl (E)-3-(4-hydroxyphenyl)prop-2- enoate; PubChem CID: 5320686 (Modify date: 2016-04-30));

[47] Robinin (lUPAC name: 5-hydroxy-2-(4-hydroxyphenyl)-7-[(2S,3R_!4R_!5R_!6S)-3_!4,5- trihydroxy-6-methyloxan-2-yl]oxy-3-[(2S,3R,4S,5R,6R)-3,4,5-trihydroxy-6- [[(2S,3R,4R,5R,6S)-3,4,5-trihydroxy-6-methyloxan-2-yl]oxymethyl]oxan-2-yl]oxychromen-4- one; PubChem CID: 5281693 (Modify date: 2016-04-30)), also referred to as Kaempferol-3- O-robinoside-7-O-rhamnoside; and

[48] Afzelin (lUPAC name: 5,7-dihydroxy-2-(4-hydroxyphenyl)-3-[(2S_!3R_!4R_!5R_!6S)-3_!4,5- trihydroxy-6-methyloxan-2-yl]oxychromen-4-one; PubChem CID 5316673 (Modify date 2016- 04-30)), also referred to as Kaempferin or Kaempferol 3-rhamnoside. Pharmaceutical composition

[49] Kaempferol or Kaempferol derivatives used for treatment of cardiac diseases and conditions as described herein will typically be administered in the form of a pharmaceutical composition. The present invention thus further provides a pharmaceutical composition comprising, as an active agent, Kaempferol or a derivative thereof, and, optionally, one or more pharmaceutically excipient(s). Accordingly, the use of Kaempferol or a Kaempferol derivative for the manufacture of a pharmaceutical composition or medicament is also envisaged herein.

[50] The term "pharmaceutical composition" particularly refers to a composition suitable for administering to a human. However, compositions suitable for administration to non- human animals are generally also encompassed by the term.

[51] The pharmaceutical composition and its components (i.e. active agents and optional excipients) are preferably pharmaceutically acceptable, i.e. capable of eliciting the desired therapeutic effect without causing any undesirable local or systemic effects in the recipient. Pharmaceutically acceptable compositions of the invention may for instance be sterile or non-sterile. Specifically, the term "pharmaceutically acceptable" may mean approved by a regulatory agency or other generally recognized pharmacopoeia for use in animals, and more particularly in humans.

[52] Kaempferol or the Kaempferol derivative is preferably present in the pharmaceutical composition in a therapeutically effective amount. By "therapeutically effective amount" is meant an amount of the active agent that elicits the desired therapeutic effect. Therapeutic efficacy and toxicity can be determined by standard procedures, e.g. in cell culture or in test 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, ED₅₀/LD₅o. Pharmaceutical compositions that exhibit large therapeutic indices are preferred.

Excipients

[53] The term "excipient" includes fillers, binders, disintegrants, coatings, sorbents, antiadherents, glidants, preservatives, antioxidants, flavoring, coloring, sweeting agents, solvents, co-solvents, buffering agents, chelating agents, viscosity imparting agents, surface active agents, diluents, humectants, carriers, diluents, preservatives, emulsifiers, stabilizers and tonicity modifiers. It is within the knowledge of the skilled person to select suitable excipients for preparing the desired pharmaceutical composition of the invention. Exemplary carriers for use in the pharmaceutical composition of the invention include saline, buffered saline, dextrose, and water. Typically, choice of suitable excipients will inter alia depend on the specific active agent used, the disease to be treated, and the desired formulation of the pharmaceutical composition. Additional active agents

[54] The present invention further provides pharmaceutical compositions comprising one or more of the active agents specified above and one or more additional active agents that are suitable for treatment of the disease to be treated. Examples of active ingredients suitable for combinations include Na+ channel blockers such as Quinidine, Ajmaline, Procainamide, Disopyramide, Lidocaine, Phenytoin, Mexiletine, Tocainide, Encainide, Flecainide, Propafenone, Moricizine, beta blockers such as Carvedilol, Propranolol, Esmolol, Timolol, Metoprolol, Atenolol, Bisoprolol; K+ channel blockers such as Amiodarone, Sotalol, Ibutilide, Dofetilide, Dronedarone; Ca+ channel blockers such as Verapamil, Diltiazem; or other agents such as Adenosine, Digoxin, or Magnesium Sulfate.

Dosage

[55] The exact dosage of Kaempferol or its derivative (or the pharmaceutical composition comprising the same) will be ascertainable by one skilled in the art using known techniques. Suitable dosages provide sufficient amounts of Kaempferol or its derivative and are preferably therapeutically effective.

[56] As is known in the art, adjustments for purpose of the treatment (e.g. remission maintenance vs. acute flare of disease), route, time and frequency of administration, time and frequency of administration formulation, age, body weight, general health, sex, diet, severity of the disease state, drug combination(s), reaction sensitivities, and tolerance/response to therapy may be required. Suitable dosage ranges for Kaempferol or its derivatives can be determined using data obtained from cell culture assays and animal studies and may include the ED₅₀. Typically, dosage amounts may vary from 0.1 to 100000 micrograms, up to a total dose of about 2 g, depending upon the route of administration. Exemplary dosages are in the range from about 0.01 mg/kg to about 10 mg/kg, from about 0.1 mg/kg to about 10 mg/kg, from about 1 mg/kg to about 10 mg/kg, from about 1 mg/kg to about 5 mg/kg, from about 0.01 mg/kg to about 1 mg/kg, or from about 0.1 mg/kg to about 1 mg/kg. Guidance as to particular dosages and methods of delivery is provided in the literature. It is recognized that treatment may require a single administration of a therapeutically effective dose or multiple administrations of a therapeutically effective dose of Kaempferol or its derivative. E.g., Kaempferol or its derivative (or a pharmaceutical composition comprising the same) might be administered daily, every 3 to 4 days, every week, or once every two weeks, or once within a month depending on formulation, half-life and clearance rate of the particular compound or composition. Administration

[57] A variety of routes are applicable for administration of the pharmaceutical composition according to the present invention. Typically, administration may be accomplished enterally. Methods of enteral delivery include oral application, for example as a tablet or capsule or int the form of powder or granulate. However, administration can also be accomplished parenterally. Methods of parenteral delivery include topical, intra-arterial, intramuscular, subcutaneous, intramedullary, intrathecal, intraventricular, intravenous, intraperitoneal, intrauterine, intravaginal, sublingual or intranasal administration.

Formulation

[58] The pharmaceutical compositions of the invention can be formulated in various forms, e.g. in solid, liquid, gaseous or lyophilized form and may be, for instance, in the form of a tablet, a pill, a capsule, a powder, a granule, a solution, an ointment, a cream, transdermal patches, a gel, an aerosol, suspensions, emulsions, syrups, liquids, elixirs, extracts, tincture or fluid extracts or in a form which is particularly suitable for the desired method of administration. Processes known per se for producing medicaments are indicated in 22nd edition of Remington's Pharmaceutical Sciences (Ed. Maack Publishing Co, Easton, Pa., 2012) and may include, for instance conventional mixing, dissolving, granulating, dragee- making, levigating, emulsifying, encapsulating, entrapping or lyophilizing processes. After pharmaceutical compositions of the invention have been prepared, they can be placed in an appropriate container and labeled for treatment of an indicated condition. Such labeling would for instance include amount, frequency and method of administration.

Kit

[59] The invention further provides a kit comprising kaempferol or a kaempferol derivative and at least one further active agent suitable for treatment of a cardiac disease as described herein as exemplified in the context of the pharmaceutical composition. The components are preferably provided in one or more containers or vials which may be associated with a notice in the form prescribed by a governmental agency regulating the manufacture, use or sale of pharmaceuticals or biological products, reflecting approval by the agency of the manufacture, use or sale of the product for human administration. [60] The present invention further envisions to an MCU activator, preferably kaempferol or a kaempferol derivative for use in a method of activating MCU in a patient suffering from a cardiac disease. Said cardiac disease may be any cardiac disease defined herein. Preferred cardiac diseases are also described herein. The preferred cardiac diseases may include cardiac arrhythmia, preferably tachydardia, or preferably atrial arrhythmia, ventricular arrhythmia, or supraventricular arrhythmia, preferably CPVT. These preferred cardiac diseases may also include congestive heart failure, preferably caused by systolic dysfunction. The congestive heart failure may be one selected from the group consisting of class I, class II, class III, and class IV according to the New York Heart Association Functional Classification, preferably class I, class II, or class III, preferably class I or class II, preferably class I.

[61] It must be noted that as used herein, the singular forms "a", "an", and "the", include plural references unless the context clearly indicates otherwise. Thus, for example, reference to "a reagent" includes one or more of such different reagents and reference to "the method" includes reference to equivalent steps and methods known to those of ordinary skill in the art that could be modified or substituted for the methods described herein.

[62] Unless otherwise indicated, the term "at least" preceding a series of elements is to be understood to refer to every element in the series. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. Such equivalents are intended to be encompassed by the present invention.

[63] The term "and/or" wherever used herein includes the meaning of "and", "or" and "all or any other combination of the elements connected by said term". [64] The term "about" or "approximately" as used herein means within 20%, preferably within 10%, and more preferably within 5% of a given value or range. It includes, however, also the concrete number, e.g., about 20 includes 20.

[65] The term "less than" or "greater than" includes the concrete number. For example, less than 20 means less than or equal to. Similarly, more than or greater than means more than or equal to, or greater than or equal to, respectively.

[66] Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integer or step. When used herein the term "comprising" can be substituted with the term "containing" or "including" or sometimes when used herein with the term "having". [67] When used herein "consisting of" excludes any element, step, or ingredient not specified in the claim element. When used herein, "consisting essentially of" does not exclude materials or steps that do not materially affect the basic and novel characteristics of the claim. [68] In each instance herein any of the terms "comprising", "consisting essentially of" and "consisting of" may be replaced with either of the other two terms.

[69] It should be understood that this invention is not limited to the particular methodology, protocols, material, reagents, and substances, etc., described herein and as such can vary. The terminology used herein is for the purpose of describing particular embodiments only, and is not intended to limit the scope of the present invention, which is defined solely by the claims.

[70] All publications and patents cited throughout the text of this specification (including all patents, patent applications, scientific publications, manufacturer's specifications, instructions, etc.), whether supra or infra, are hereby incorporated by reference in their entirety. Nothing herein is to be construed as an admission that the invention is not entitled to antedate such disclosure by virtue of prior invention. To the extent the material incorporated by reference contradicts or is inconsistent with this specification, the specification will supersede any such material.

[71] A better understanding of the present invention and of its advantages will be obtained from the following example, offered for illustrative purposes only. The example is not intended to limit the scope of the present invention in any way.

EXAMPLES

Example 1 : SR-mitochondria calcium transfer

[72] Transfer of calcium from sarcoplasmatic reticulum (SR) into mitochondria was measured in cultured HL-1 cardiomyocytes. HL-1 cells were cultured as described previously (Claycomb, PNAS, 1998). For the measurement of SR-mitochondria calcium transfer cells were plated at 20,000 cells per well in a 96-well plate one day prior to experiments. Cells were stained with 6μΜ rhod-2 AM ester and 0.12% (w/v) pluronic F-127 for 30 min at 37 'C. Afterwards cells were washed with external solution containing (in mM) 140 NaCI, 6 KCI, 1 MgCI, 10 Glucose, 20 HEPES, 1 EGTA (pH 7.4) and incubated at 37°C for 20 min to allow complete intracellular de-esterification of the dye. An additional washing step with calcium- free external solution was performed before permeabilizing the cells with 100 mM digitonin in internal solution containing (in mM) 1 BAPTA, 20 HEPES, 100 L-Aspartic acid potassium salt, 40 KCI, 0.5 MgCI, 2 maleic acid, 2 glutamic acid, 5 pyruvic acid, 0.5 KH2P04, 5 MgATP, 0.46 CaCI2 (pH 7.2) for 1 min. Next, cells were washed 3-times for 1 .5 min with internal solution. The internal solution was supplemented with different concentrations of either Kaempferol or DMSO as a vehicle control. Measurements were performed with the Tecan Reader Infinite 200 PRO at excitation wavelength 540(±9) nm and emission wavelength 580(±20) nm. The measurement period was 1.5 minutes with a sampling rate of 650ms. After 30 seconds 10mM caffeine was added to open RyRs (= ryanodine receptors) and release Ca2+ from the internal stores of the SR.

[73] Kaempferol induced release of calcium from the sarcoplasmic reticulum in a dose- dependent manner (Figure 1 ).

Example 2: Murine model of catecholamine-induced polymorphic ventricular tachycardia (CPVT)

[74] Mice harboring the CPVT-associated RyR2^R4496C mutation serve as the most commonly used murine model system for autosomal dominant CPVT and were housed in the animal facility of the Walther Straub Institute under standard breeding conditions. Animals heterozygous for the aforementioned RyR2 mutation where mated with RyR2 wild type mice to obtain heterozygous RyR2^R4496C/WT mice. These CPVT mice were used for experiments and healthy mice with two wild type alleles of RyR2 served as a control. Animals of either sex aged 8 to 16 weeks were subjected to experiments. The breeding facilities and all experimental protocols were approved by the Bavarian Government (Regierung von Oberbayern) and Austrian Government (Bundesministerium fur Wissenschaft, Forschung und Wirtschaft), respectively.

Example 3: Isolation of murine ventricular myocytes

[75] Ventricular cardiomyocytes from RyR2 mutant mice and their wildtype littermates were isolated by retrograde perfusion through the aorta using a standardized enzymatic digestion protocol (O'Connel et al. 2003) with minor modifications. After cervical dislocation, the heart was quickly excised and arrested in ice-cold Tyrode's solution supplemented with 10 lU/ml heparin to avoid clogging of blood during the isolation process. To free the coronaries of blood, hearts were flushed with Tyrode's solution by means of a blunt needle inserted into the aorta. The heart attached to the needle and secured by a suture was then placed on a Langendorff mode perfusion system and retrogradely perfused at constant 37°C. After being perfused with oxygenated Tyrode's solution containing 20 mM creatine for 5 minutes, the heart was digested by perfusion with Liberase TM dissolved in creatine- containing Tyrode's solution at a final concentration of 0.0375 μg ml for 0.7 sec/mg heart weight. The ventricles were cut away from the perfusion setup and transferred to calcium Tyrode's solution containing 12.5 μΜ CaCI₂ and 10% FCS to stop digestion and cut into small pieces. After mechanical separation by trituration, the suspension was filtered through a 200μηι nylon mesh and myocytes were allowed to settle/sediment by gravity for 10 minutes. This procedure ensures fibroblasts to remain in the supernatant with concentration of cardiomyocytes mainly in the pellet. Cells were then transferred into Tyrode's solution with 1 .5 mM CaCI₂ to reintroduce nearly physiological calcium concentrations and sort out calcium-intolerant cardiomyocytes displaying spontaneous contractions. Only rod-shaped cells, quiescent when unstimulated and excitable were used for experiments.

Example 4: Human model of CPVT

[76] iPS cells carrying the Ry 2^S406L-mutation were obtained from a 24-year old Caucasian female CPVT patient and have been characterized before (Jung et al. 2012). Cells obtained from a 32-year-old female Caucasian control without history of cardiac disease scheduled for plastic surgery to undergo dermal biopsy served as a healthy control.

[77] Human iPSC generation via reprogramming of primary skin fibroblasts and cardiomyocyte differentiation was performed as described previously (Moretti et al, 2010a,b). Briefly, dermal-biopsy specimens were minced and placed on culture dishes. Fibroblasts migrating out of the explants were passaged twice and infected with a combination of retroviruses encoding human transcription factors OCT4, SOX2, KLF4 and c-MYC and cultured on murine embryonic feeder cells until iPSC colonies could be picked. Differentiation of embryonic bodies was achieved by aggregating the cells on low-attachment plates and embryonic bodies were plated on gelatin-coated dishes at day 7. Between days 20 and 30, areas that exhibited spontaneous contraction, indicative of cardiac differentiation, were microdissected, plated on fibronectin-coated plates, and maintained in culture in differentiation medium containing 2% fetal-calf serum for 3-12 months. For single cell experiments microdissected areas were enzymatically dissociated with 250 μΙ_ of type II collagenase (Worthington) for 1 h at 37°C and 700 rpm. Depending on dissociation, up to 4 further digestion steps (for a maximum of 30 min each) were performed. Afterwards, remaining cell clumps were subjected to a 10 min digestion step with Accumax in DPBS (Millipore, Merck KGaA). Single cells were plated on glass bottom dishes (MatTek) coated with 10% fibronectin over night and subjected to further experiments after incubation at 37°C and 5% C02 on an average time of 7 days.

Example 5: Confocal microscopy

[78] Cardiomyocytes were loaded with 3 μΜ of the calcium indicator Fluo-4 AM (Life technologies) and 0.06 % (w/v) pluronic F-127 (Sigma-Aldrich) under protection from light for 40 minutes at RT in external solution containing (in mM) 140 NaCI, 4 KCI, 1 MgCI₂, 1 CaCI₂, 10 glucose, 5 HEPES, 10 BDM for murine ventricular cardiomyocytes or external solution containing (in mM) 140 NaCI, 4 KCI, 1 MgCI₂, 1 .8 CaCI₂, 10 glucose, 5 HEPES for human iPSC-derives cardiomyocytes respectively. For subsequent de-esterification of the dye, cells were incubated in external solution without Fluo-4 AM for 20 minutes. Calcium transients in fluo-4 loaded cardiomyocytes were elicited by field stimulation using a Stimulator S48 (Grass) to apply 5ms test pulses at 0.5 Hz with 30 V/cm electrode distance and visualized by confocal microscopy on a LEICA TCS SP5 inverted microscope equipped with a HCX PL APO CS 63x/1.4 oil immersion objective. Fluorescence was excited with the 488 nm line of an Arg laser with 20% of laser power further reduced to 8% intensity by an acusto optic tunable filter (AOTF). Emission was collected between 498 and 627 nm. Spectral settings were kept constant throughout all experiments. Line scan series were generated by recording lines of 512px spanning the entire myocyte for 2 minutes at 400Hz (one line/2.5msec). In both, murine and human cardiomyocytes, treatment with kaempferol significantly reduced the number of spontaneous arrhythmogenic Ca²⁺ waves during diastole (Figure 2, Figure 4).

[79] Calcium transient kinetics were further analyzed using pClamp 10.4 software (Molecular Devices LLC, California, USA). The amount of calcium released from the SR is expressed as AF/F₀, the activation time of the aforementioned release is expressed as time to peak and calcium clearance from the cytosol was analyzed by calculating the inactivation constant Tau of a monoexponential fit of the decay phase of the calcium transient. Treatment of murine cardiomyocytes with kaempferol significantly enhances systolic Ca²⁺ release and accelerated Ca²⁺ removal from the cytosol, indicating positive inotropy and lusitropy (Figure 5).

Example 6: In vivo administration of kaempferol

[80] RyR2^R4496C+/" mice of either sex at a mean age of 1 1 .7 ± 3.3 weeks were treated with 12 mg/kg bodyweight of kaempferol via 1003D osmotic minipumps (ALZET, DURECT Corporation, Cupertino, California). Filling of the pumps was accomplished with a small syringe and a blunt-tipped 27 gauge filling tube. To achieve sterility of the respective solutions, a 0.22μηι filter (Millex -GV, Millipore, Merck KGaA) was interposed between syringe and filling tube. Before implantation, pumps are wiped with isopropanol and primed in 0.9% NaCI solution until surgery. During the whole procedure, pumps were only handled with surgical gloves to avoid contact with skin oils. Pumps were implanted subcutaneously between scapulae under general anesthesia (Avertin 0.025 mg/kg, 1.25 % tribromoethanol in NaCI) whilst implanter was blinded to the content administered by the mini-osmotic pumps. For determination of the filling volume and verification of correct filling, pumps were weighed before and after filling with the drug solution. Difference in weights thereby gives the net volume of the solution loaded. Following implantation, interstitial fluid enters the pump via the semipermeable outer membrane thereby swelling the osmotic layer. This swelling results in a defined compression of the impermeable inner drug reservoir leading to a strictly rate- controlled drug release. [81] Mice were constantly monitored for signs of pain and distress during and after surgery. To screen for arrhythmias a one-lead ECG according to Einthoven was performed on day 3. Under inhalation anaesthesia with 0.5 mL/h isoflurane (Baxter), positive and negative electrodes were positioned on the mouse's left and right hind legs, respectively. A third electrode placed on the right hind leg served as grounding. Body temperature was maintained at 37°C by a thermostatically regulated heating pad (Harvard Apparatus, Mass) and was constantly controlled by a rectal thermometer. After baseline ECG for an average of 15 min, mice were injected IP with suprarenin/L-adrenaline (2 mg/kg; Fresenius) and caffeine (120 mg/kg; Sigma-Aldrich), continuously monitored for episodes of ventricular tachycardia for 20 mins and sacrificed subsequently. [82] Administration of Kaempferol did not influence parameters of the ECG but significantly reduced arrhythmias (Figure 3).

Example 7: Murine heart failure model

[83] To induce pressure-overload induced heart failure in mice, CPVT mice received transverse aortic constriction. To this aim, mice were anesthetized (0.5 mg/kg medetomidin, 5 mg/kg midazolam, 0.05 mg/kg fentanyl) and the thorax was opened by a small incision of the skin and sternum. The aortic arch was localized and constricted around a 27G needle between the brachiocephalic artery and the left common carotid artery. After surgery mice were constantly monitored for 3 weeks for signs of pain or distress. Success of the aortic constriction was controlled by determining the heart weight to tibia length ratio after 3 weeks prior to experiments, since pressure-overload leads to cardiac hypertrophy.

Example 8: Measurement of inotropy in organotypic heart slices.

[84] TAC-operated CPVT mice were killed by cervical dislocation and hearts were excised quickly, before being stored in ice-cold Tyrode's solution containing (in mM) 136 NaCI, 5.4 KCI, 1 MgH₂P0₄, 10 glucose, 0.9 CaCI₂, 30 2,3-butanedione-monoxime (BDM), 5 HEPES (pH 7.4). Prior to slicing, the tissue was embedded in 4% low-melting agarose dissolved in glucose-free Tyrode's solution at 37°C and subsequently bonded (Super Bond, Kent Germany) to the vibratome's (VT1200S, Leica, Germany) sample holder. The sample was quickly covered with ice-cold Tyrode's solution and cut into 300 μηη thick tissue slices using steel blades (Wilkinson, Germany). After preparation, the slices were kept in ice-cold Tyrode's solution for 30 min before they were used for further experiments. Functional measurements were carried out in horizontal organ baths (Mayflower, Hugo Sachs Elektronik (HSE), Germany). The slices were bonded (Super Bond) to triangular vessel holders and connected to isometric force transducers (F30, HSE). The slices were continuously perfused with pre-warmed (37°C) and pre-gassed Tyrode's solution and pulsed by external field stimulation at 0.5Hz to record contractile force before and after addition of kaempferol.

[85] An increase in contractile force and acceleration of relaxation was observed after addition of kaempferol (Figures 6 and 7).

Example 9: Statistical Analysis

[86] Data are presented as mean ± S.E.M. Statistical analysis was performed with Excel/graphpad. Statistical significance was evaluated with unpaired Student's t-test or Fisher's exact test. P<0.05 was considered statistically significant, where (^*) represents P<0.05,(^**) P<0.01 and (^***) PO.001 .

Claims

1 . Kaempferol or a kaempferol derivative for use in a method of treatment of a cardiac disease in a subject, wherein the cardiac disease can be alleviated by activating mitochondrial calcium uniporter (MCU).

2. The kaempferol or kaempferol derivative for use according to claim 1 , wherein the disease is arrhythmia.

3. The kaempferol or kaempferol derivative for use according to claim 2, wherein the disease is tachycardia.

4. The kaempferol or kaempferol derivative for use according to claim 2 or 3, wherein the disease is atrial arrhythmia, ventricular arrhythmia, or supraventricular arrhythmia.

5. The kaempferol or kaempferol derivative for use according to any one of claims 2 to 4, wherein the disease is catecholaminergic polymorphic ventricular tachycardia (CPVT).

6. The kaempferol or kaempferol derivative for use according to claim 1 , wherein the disease is congestive heart failure.

7. The kaempferol or kaempferol derivative for use according to claim 6, wherein the heart failure is caused by systolic dysfunction.

8. The kaempferol or kaempferol derivative for use according to claim 6 or 7, wherein the heart failure is one selected from the group consisting of class I, class II, class III, and class IV according to the New York Heart Association Functional Classification, preferably class I, class II, or class III, preferably class I or class II, preferably class I.

9. The kaempferol or kaempferol derivative for use according to any one of claims 6 to 8, wherein the heart failure is selected from the group consisting of left-sided heart failure, including heart failure with reduced ejection fraction or systolic heart failure and heart failure with preserved ejection fraction or diastolic heart failure, right-sided heart failure, biventricular heart failure, congestive heart failure, acute heart failure, chronic heart failure, and acute decompensated heart failure.

10. The kaempferol or kaempferol derivative for use according to any one of the preceding claims, wherein said kaempferol or kaempferol derivative has the following general formula (I):

(I) wherein R1 , R2, R3, and R4 are identical or different and independently selected from hydrogen, alkyl, acyl, aliphatic acyl, araliphatic or aromatic acyl group or a sugar or sugar acid; or a pharmaceutically acceptable salt thereof.

1 1 . The kaempferol or kaempferol derivative for use according to claim 10, wherein the kaempferol derivative is selected from Astragalin, Kaempferol 3-O-neohesperidoside, Kaempferitrin, Tiliroside, Robinin, and Afzelin.

12. The kaempferol or kaempferol derivative for use according to claim 3, wherein the kaempferol or kaempferol derivative is kaempferol.

13. The kaempferol or kaempferol derivative for use according to claim 4, wherein the kaempferol or kaempferol derivative is kaempferol.

14 The kaempferol or kaempferol derivative for use according to claim 5, wherein the kaempferol or kaempferol derivative is kaempferol.

15. The kaempferol or kaempferol derivative for use according to claim 7, wherein the kaempferol or kaempferol derivative is kaempferol.

16. The kaempferol or kaempferol derivative for use according to claim 8, wherein the kaempferol or kaempferol derivative is kaempferol.

17. The kaempferol or kaempferol derivative for use according to claim 9, wherein the kaempferol or kaempferol derivative is kaempferol.

18. The kaempferol or kaempferol derivative for use according to any one of the preceding claims, wherein the subject is a human.

19. A pharmaceutical composition comprising kaempferol or a kaempferol derivative for use in the treatment of a cardiac disease in a subject, wherein the cardiac disease can be alleviated by activating the mitochondrial calcium uniporter (MCU).

20. The pharmaceutical composition for use according to claim 19, wherein the cardiac disease is a disease as defined in any one of claims 2 to 9.

21 . Kaempferol or a kaempferol derivative for use in a method of activating MCU in a patient suffering from a cardiac disease.

22. A kit comprising kaempferol or a kaempferol derivative and at least one further active agent suitable for treatment of a cardiac disease, wherein the cardiac disease can be alleviated by activating mitochondrial calcium uniporter (MCU).

23. A method for the treatment or prevention of a cardiac disease, wherein the cardiac disease can be prevented or alleviated by activating mitochondrial calcium uniporter (MCU), comprising administering kaempferol or a kaempferol derivative to a subject in need thereof.

24. Use of kaempferol or a kaempferol derivative for the manufacture of a medicament for the treatment or prevention of a cardiac disease, wherein the cardiac disease can be alleviated by activating mitochondrial calcium uniporter (MCU).