Patent Application
20160354359
The present invention relates to a method of handling a potential organ donor immediately after brain death and until organs are harvested, and a composition and an infusion solution.
It is well known that there is a great shortage of donor organs, which are suitable for transplantation.
Hemodynamic instability during and after brain death of a heart-beating donor is often associated with the deterioration of graft viability, leading to organ exclusion.
There is a need for a method of treating the potential organ donor after brain death and before harvesting of organs, which decreases the rejection rate of organs that are harvested from such donor.
Accordingly, an object of the present invention is to mitigate, alleviate or eliminate one or more of the above-identified deficiencies and disadvantages singly or in any combination.
According to an aspect of the invention, there is provided a composition for intravascular administration for treatment of a brain-dead, heart-beating, respirated potential organ donor, comprising: noradrenaline and a NET inhibitor.
In an embodiment, the NET inhibitor may be cocaine or a stimulating analogue thereof. In another embodiment, the NET inhibitor may be at least one tricyclic antidepressant included in the group comprising: Amitriptyline (ELAVIL®); Clomipramine (ANAFRANIL®); Doxepin (ADAPIN®, SINEQUAN®); Imipramine (TROFANIL®); Trimipramine (SURMONTIL®); Amoxapine (ASENDIN®); Desipramine (NORPRAMIN®); Maprotinile (LUDIOMIL®); Nortriptyline (PAMELOR®); and Protriptyline (VIVACTIL®). In a further embodiment, the NET inhibitor may be at least one agent included in the group comprising: Venlafaxin (EFFEXOR®); Atomexetine (WELLBUTRIN®); Duloxetine (CYMBALTA®); Mirtacapine (REMERON®); Norclomipramine; Oxaprotiline; Lofepramine; Reboxetine; Maprotiline; Nomifensine; Doxepin; Mianserin; Viloxazine; Mirtazapine; and Nisoxetine.
According to a still further embodiment, the composition may further comprise at least one of: adrenaline, hydrocortisone, thyroxin, insulin, triiodotyronine, a vasopressor agent, such as desmopressin, and methylprednisolone.
The NET inhibitor may be present in an amount of 0.2 to 5 times of the amount of noradrenaline. In the case of cocaine, the ratio between cocaine and noradrenaline may be about 1:1.
In another aspect, there is provided an infusion solution comprising the composition mentioned above and a pharmaceutically acceptable medium, such as pure water, Ringer's acetate solution or physiological sodium chloride solution. The composition may be dissolved in the pharmaceutically acceptable medium in an amount of about 1 mg of noradrenaline, and about 1 mg of cocaine in about 50 ml of fluid.
In a further aspect, there is provided a method for treatment of a brain dead, heart-beating, respirated potential organ donor, comprising: infusion of the infusion solution mentioned above, in an amount sufficient for maintaining a mean arterial pressure of about 60 mmHg.
In a still further aspect, there is provided a kit for intravenous administration for treatment of a brain dead, heart-beating, respirated potential organ donor, comprising: an infusion bag comprising an infusion solution as mentioned above; an infusion pump for pumping the infusion solution to a needle inserted into the vascular system of the donor for controlling the amount of infusion solution entered into the donor and tubings for interconnecting the bag, pump and needle. The kit may comprise several sets of infusion bags, infusion pumps and tubings. The kit may further comprise a computer for controlling the pump or pumps, whereby the computer is operated according to a predetermined control strategy.
In a yet further aspect, there is provided a method of infusing a solution into the circulation system of a brain dead, heart-beating, respirated potential organ donor, comprising: determining that the donor is brain dead; continuing or initiating respiration for oxygenation of the blood; infusion of an infusion solution as mentioned above; and controlling the infusion by means of a computer.
Further objects, features and advantages of the invention will become apparent from the following detailed description of embodiments of the invention with reference to the drawings, in which:
Below, several embodiments of the invention will be described. These embodiments are described in illustrating purpose in order to enable a skilled person to carry out the invention and to disclose the best mode. However, such embodiments do not limit the scope of the invention. Moreover, certain combinations of features are shown and discussed. However, other combinations of the different features are possible within the scope of the invention.
In the context of the present description and embodiments the following definitions apply: The term “cocaine analogue” is intended to mean an analogue, which acts in the same or a similar way as cocaine in preserving the organs in a brain-dead, heart-beating, respirated donor before harvesting of the organs. The term “pharmaceutically acceptable” means a non-toxic material that does not decrease the effectiveness of the biological activity of the active ingredients. Such pharmaceutically acceptable buffers, carriers or excipients are well-known in the art, see for example Remington's Pharmaceutical Sciences, 18th edition, A. R Gennaro, Ed., Mack Publishing Company (1990), and Handbook of Pharmaceutical Excipients, 3rd edition, A. Kibbe, Ed., Pharmaceutical Press (2000). The term “physiologically acceptable solution” means a solution that does not interfere substantially with the fluids in the body.
An object of the below described embodiments is to improve the outcome of organ harvesting and transplantation from a donor, which has been declared brain-dead but still has a beating heart and which is ventilated.
The process of becoming brain dead is a traumatic experience for the body and its organs. Thus, a thorough understanding of the endocrinal, hormonal and metabolic events before, during and after declaration of brain death would be of interest for determining intervention.
Brain death may be initiated by a massive necrosis of brain cells, which may be due to different causes. Such necrosis may result in increased osmotic pressure in the brain, resulting in water absorption via the blood-brain barrier. Since the skull cannot expand, the intracranial pressure rises considerably.
When the intracranial pressure exceeds the systolic blood pressure, the brain is exposed to an ischemic condition, because blood cannot enter the brain. The brain may react by increasing the heart rate and blood flow and by increasing the systemic vascular resistance. In addition, the adrenal gland increases the level of circulating adrenaline (also termed epinephrine or adrenalin) and noradrenaline (also termed norepinephrine, nor-adrenaline, or nor-epinephrine). This is called the Cushing reflex.
The heart rate may increase by several hundred percent, to a maximum heart rate. The blood pressure may increase to above 200 mmHg. This massive reaction is also called the “catecholamine storm” or “sympathetic autonomous storm”. The adrenaline and/or noradrenaline levels may increase by 70 times, as described in more detail below.
If this increase of systolic blood pressure is insufficient for delivering blood to the brain, the brain will maintain its ischemic state. However, the brain cannot sustain more than about 10 minutes without blood supply.
If the intracranial pressure, for example due to the increased osmotic pressure, rises to more than about 300 mmHg, the brain cannot withstand such high pressures but disintegrates. The end result will be a progressive brain swelling, and herniation of the hippocampal gyri with lateral pressure of the brainstem, with eventual loss of brainstem function and loss of spontaneous respiration. This may results in herniation of the brain stem through the foramen magnum.
Other causes of (brain) death may result in somewhat different processes.
In Sweden, brain death is defined as irreversible loss of function of the entire brain including the brainstem. There are several indicia of brain death, which are of less interest for the present embodiments. However, after brain death, there is no cerebral blood circulation and no spontaneous respiration. The body temperature should be above 33° C. and there should be no drug intoxication.
After brain death, the brain, including the brain stem, cannot retain its function, because it is permanently damaged.
During the “catecholamine storm,” the levels of adrenaline and noradrenaline may rise considerably. During experiments on dogs, an increase in blood concentration of adrenaline from about 0.40 to 75 nmol/L and an increase of noradrenaline from about 0.40 to 12 nmol/L were obtained within one to three minutes.
After occurrence of brain death, the hypothalamic-pituitary-adrenal axis is disrupted. However, necrosis is followed by a release of cytokines, especially IL-6, which stimulates the adrenal gland to produce adrenaline and noradrenaline. Eventually, the production of these inotropics will be reduced and after some 60 minutes, the levels of adrenaline and noradrenaline will be lower than normal. This will result in vasoplegia by loss of the sympathetic vasotonus.
The pituitary gland also produces antidiuretic hormone (ADH), or vasopressin, which acts on the kidneys in order to control the water resorption. ADH has a short half-life-time of about 15 minutes and a shortage of ADH will occur after some 60 minutes (with large individual variations). Depletion of ADH may result in diabetes insipidus, resulting in production of large quantities of urine in the order of several liters per hour. Unless replacement of fluid takes place, diabetes insipidus will result in hypovolemia, a further reduction of blood pressure and eventual loss of circulation, resulting in ischemic damage of all organs.
Moreover, the pituitary gland produces adrenocorticotropic hormone (ACTH), which stimulates secretion of glucocorticoids, which stimulates the synthesis of adrenaline and noradrenaline.
In addition, the pituitary gland produces thyroid-stimulating hormone (TSH), which stimulates the thyroid gland to secrete the hormones thyroxin (T4) and triiodotyronine (T3). Depletion of T4 and T3 may result in a change from aerobic to anaerobic metabolism in for example the heart, which may result in increased lactate and pyruvate levels.
Because the pituitary gland is dependent on the hypothalamus, the operation of the pituitary gland is reduced or ceases, resulting in decreased circulating levels of for example T3, T4, ADH, ACTH, cortisol and insulin. This results in impaired aerobic metabolism, increased anaerobic metabolism, depletion of high-energy phosphates and increased lactate production.
Side effects of high levels of catecholamines are tachycardia, atrial and ventricular arrhythmias as well as conduction abnormalities.
Pulmonary edema may result after high levels of catecholamines, especially adrenaline.
Because of vasoconstriction caused by catecholamines, the organs may lose perfusion.
Hypothalamus controls body temperature, and the failure of the hypothalamus may result in hypothermia.
There are a number of different strategies suggested in the literature for maintaining organs after brain death. The fact that it is possible with prolonged somatic support has been reported for a pregnant woman with brain death. By full ventilatory and nutritional support, vasoactive drugs, maintenance of normothermia, hormone replacement and other supportive measures, the fetus could be born several weeks after brain death of the mother, thereby improving the survival prognosis for the fetus.
A review article by Kenneth E. Wood and John McCartney entitled: “Management of the potential organ donor,” published in Transplantation Reviews 21 (2007), pages 204-218, and available online at the website “sciencedirect.com,” summarizes the state of the art in this field.
In Sweden, it is permitted to maintain the donor for 24 hours after brain death until organ harvesting is performed. After harvesting, the organs are examined for viability and stored, normally under hypothermic conditions until transplantation.
Since ADH decreases rapidly, it is necessary to address this issue. Depletion of ADH sooner of later results in diabetes insipidus with high urine volumes leading to hypovolemia. This has been counteracted by infusion of large volumes of colloidal or crystalloid fluid, such as Ringer's solution. Another approach is to add a vasopressor agent, such as arginine vasopressin, desmopressin, DDAVP or Minirin.
The decrease of thyroid hormone level should also be addressed in order not to aggravate metabolism. Thus, addition of T4 and/or T3 may be appropriate.
The reduction in ACTH and cortisol may be addressed by giving methylprednisolone, or a similar agent.
In order to maintain proper perfusion of the organs, especially the kidney, it is considered that a mean arterial pressure MAP of at least 60 mmHg should be upheld, see for example the above-mentioned review article. This may be done by adding catecholamines, such as noradrenaline and/or adrenaline. However, there is evidence that addition of adrenaline and/or noradrenaline may aggravate the conditions for some organs, and there is a tendency in the art to avoid the addition of catecholamines. Traditionally, dopamine has been the inotrope of choice in doses titrated to ensure cardiac output and vasoconstriction to ensure perfusion pressure gradients to the myocardium and the renal circulation.
Catecholamines have a half-life of approximately a few minutes when circulating in blood. Normal secretion in the adrenal medulla of adrenaline is 0.2 μg/kg/min and of noradrenaline 0.05 μg/kg/min.
It is reported in the literature that administration of noradrenaline has been associated with myocardial damage and initial nonfunctioning after cardiac transplantation. It is hypothesized that the “catecholamine storm” after brain death may cause myocardial ischemia or rapid desensitization of the beta-adrenergic signaling pathway. Administration of further noradrenaline after brain death may further desensitize the myocardial beta-adrenergic signaling.
Another possible explanation might be that, under massive catecholamine release, the uptake and inactivation metabolization systems may be saturated, resulting in a down-regulation of beta adrenergic cardiac receptors (BAR), i.e. a reduction of BAR density, which may be dose dependent. The recovery potential of BAR remains unknown, but may have an impact on organ function.
In addition, catecholamines may sulfoconjugate, which is regarded as an inactivation process by which the organism “pools” free plasma catecholamines into inactivated derivatives, which subsequently are deconjugated and released.
Thus, there is evidence that high levels of catecholamines may impair the alpha- and/or beta-receptors potency. In addition, the elimination system may be saturated, which may finally result in poor graft outcome.
A fundamental idea of the present embodiments is to replace at least some of the substances and/or hormones that are no longer excreted, or are excreted in substantially lower levels, by the brain dead body compared to a living body. The focus is to maintain hemodynamic stability by cardiovascular support because it may maintain all of the donor organs in the best possible condition.
The inventor has found that adrenaline and noradrenaline are two substances that would be beneficial to add, but the addition of either of the substances is controversial and may result in undesired side effects as mentioned above.
Although the exact mechanism is unknown today, it is believed that a high level of catecholamines, such as under the “catecholamine storm” will cause a depletion of the stores of catecholamine normally found in the nerve terminals and adrenal medulla. In addition, the vascular tonus is lost, because the nerve terminals receive no signals from the brain.
Noradrenaline is normally produced in the pre-synaptic nerve terminal from tyrosine, which is an amino acid present all over the body in large quantities.
Tyrosine is transported into the varicosity 11 via a transporter 15 and into the cytoplasm, wherein the tyrosine is converted to DOPA under the influence of an enzyme; tyrosine hydroxylase (TH). This step is considered to be the rate-limiting step in the synthesis of noradrenaline and adrenaline.
DOPA is transformed to dopamine in the cytoplasm under the influence of an enzyme; aromatic L-amino acid decarboxylase (AAADC).
Dopamine is taken up into vesicles 16 via an active transporter 17 called VMAT-2 (vesicular monoamine transporter), which is relatively non-specific and can transport different catecholamines, such as noradrenaline and dopamine, and other substances. Only about 50% of the dopamine produced is normally transported into the vesicles 16; the rest is metabolized by an enzyme called MAO (monoamine oxidase), see further below. There are a great number of vesicles in the nerve terminal.
Inside the vesicle, there is an enzyme; dopamine-β-hydroxylase (DβH), which converts the dopamine entering the vesicle into noradrenaline (NA). In addition, any noradrenaline present inside the varicosity 11 is transported into the vesicle 16 by the same transporter 17 VMAT-2. In this way, noradrenaline is reused. A portion of the noradrenaline inside the varicosity does not enter the vesicle 16 but is metabolized by the enzyme MAO. Thus, there is a competition between the enzyme MAO and the active transporter 17 VMAT-2, both with regard to dopamine and noradrenaline.
The concentration of noradrenaline inside the vesicle is very high. A concentration in the range of 1 mole/liter has been reported.
At depolarization of the nerve cell membrane at the arrival of a stimulation signal, several voltage dependent calcium ion channels 18 allow the passage of calcium ions through the varicosity membrane 12. Elevated levels of calcium ions promote the fusion of vesicular membrane with the membrane of the varicosity with subsequent exocytosis of noradrenaline, NA. The fusion process involves the interaction of specialized proteins associated with the vesicular membrane (VAMPs, vesicle-associated membrane proteins) and the membrane of the varicosity (SNAPs, synaptiosome-associated proteins). When the vesicle emits its content into the synaptic cleft, the noradrenaline passes into the synaptic cleft and may interact with alpha- and beta-receptors present at the effector cell membrane, as shown by arrows in
The released noradrenaline may also interact with presynaptic receptors of alpha-2-type and beta-type. The alpha-2-receptor may influence directly on the vesicle and diminish the release of noradrenaline. The beta-receptor may facilitate the release of noradrenaline. The mechanism is not clearly understood for such direct influence of the release of the noradrenaline.
After some time, noradrenaline attached to the receptors is released from the receptors in the synaptic cleft. The noradrenaline present in the synaptic cleft is transported into the adrenal varicosity by an active transporter 19, called NET (norepinephrine transporter, norepinephrine=noradrenaline). This transporter has a high affinity for noradrenaline. NET removes free noradrenaline from the synaptic cleft, often within 0.1 seconds. However, a small portion of the free noradrenaline in the synaptic cleft passes out to the surrounding interstitial fluid and subsequently to the blood circulation. Circulating noradrenaline is rapidly metabolized in the liver, normally within a few minutes.
Thus, most of the noradrenaline released during exocytosis is reused. A portion is lost to the circulation and a portion is lost inside the adrenergic varicosity due to metabolization by MAO before entering the vesicle 16. Such lost noradrenaline is replaced by newly produced noradrenaline from tyrosine as explained above.
There is a negative feed-back regulation of the synthesis of noradrenaline from tyrosine. Thus, a high concentration of noradrenaline at the presynaptic alpha-2-receptors seems to decrease the production of noradrenaline, probably via interference with the rate-limiting enzyme TH.
The distance from the synaptic cleft to the blood circulation may be about 0.1 mm to several millimeters and is thus very much larger than the synaptic cleft. Thus, it takes long time for noradrenaline to diffuse from the synaptic cleft to the blood circulation and vice versa. Consequently, the blood concentration of noradrenaline in a living human body is normally low. In addition, it takes a high concentration in the blood in order for some noradrenaline to diffuse to the synaptic cleft and influence upon the receptors of the effector cell membrane.
Adrenaline is produced from noradrenaline by an extra enzymatically driven step in the adrenal medulla. The enzyme is called phenylethanolamine N-methyltransferase (PNMT) and converts noradrenaline to adrenaline. This enzyme is present essentially only in the adrenal medulla. The adrenal medulla comprises nerve terminals similar to the adrenergic varicosity shown in
The above description is valid for a living body, such as the human being. When the body becomes brain dead, this condition is preceded by a catecholamine storm as explained above. Thus, as much noradrenaline as possible is released by exocytosis in the sympathetic nerve system, causing increase of the vascular system resistance by means of the alpha-receptors of the effector cells. Consequently, all vesicles 16 in the nerve terminal are emptied into the synaptic cleft. Possibly, the uptake mechanism of the NET transporter 19 is overloaded and the concentration of noradrenaline in the synaptic cleft will increase, probably by a factor above 100. This will cause a disturbance of the reuse of noradrenaline and the reuse of the vesicles after exocytosis. In addition, there will be a down-regulation of the release of the vesicles by the alpha-2-receptors. Furthermore, the new production of noradrenaline will be down-regulated by the high synaptic concentration of noradrenaline. Most of the produced noradrenaline will pass out into the blood circulation and be metabolized by the liver. Consequently, all stores of noradrenaline in the nerve terminals will be used up and the operation of the nerve terminals will be severely disturbed.
The adrenal medulla will also release all its storage of adrenaline as well as noradrenaline into the blood. The circulating catecholamines will be rapidly metabolized by the liver.
Consequently, after the catecholamine storm, all stores of catecholamines, particularly noradrenaline and adrenaline are exhausted. There is only a small new production of noradrenaline because the production from tyrosine takes several hours to adjust itself to the new situation.
Thus, according to an embodiment of the present invention, adrenaline may be added in concentrations similar to those normally encountered in the blood. The added adrenaline interacts with beta-receptors to promote for example cardiac output. Adrenaline has numerous other actions in the body as is well known to the skilled person.
According to another embodiment, noradrenaline may be added in concentrations sufficient to cause diffusion from the blood to the synaptic cleft and to the receptors present therein, normally alpha-receptors, in order to interact with for example alpha-receptors to cause vasoconstriction. Noradrenaline has numerous other actions in the body as is well known to the skilled person.
However, noradrenaline is normally produced and normally acts at sites different from the blood. This means that noradrenaline in the blood circulation may have a fast and direct effect at certain locations of the body, for example the kidney, while it may take longer time and have less effect at other locations, for example the vascular system. Thus, the consequence of adding noradrenaline to the blood circulation is very complex and incongruous.
One mechanism which may decrease the action of the noradrenaline circulating in the blood and diffusing to the synaptic cleft, may be the fact that any noradrenaline reaching the synaptic cleft will be rapidly taken up by the NET transporter and be entered into the presynaptic nerve terminal. Since the nerve terminal is depleted of noradrenaline, this action will be fast. Thus, the NET transporter will compete with the activation of the effector cell receptors and decrease the action of the added circulating noradrenaline. In order to obtain an effect, a high concentration of noradrenaline in the blood will be required, which is incompatible with other operations in the body.
If noradrenaline is added to the blood circulation, noradrenaline will be absorbed or soaked up by the nerve terminals. Thus, the state of depletion of the nerve terminals after the catecholamine storm may be reversed and normal operation of the nerve terminals may be resumed. However, because the brain dead body does not emit any nerve signals, the calcium channels remain unstimulated and no exocytosis and release of noradrenaline may take place.
The inventor has found that the addition of cocaine together with noradrenaline would permit the use of much lower levels of noradrenaline in the blood circulation and still obtain the desired effects of vasoconstriction. One hypothesis for explaining this result may be that the cocaine acts as NET inhibitor, which is previously known. By blocking the reuptake of the noradrenaline from the synaptic cleft, the NET transporter will no longer compete with the alpha-receptor and the noradrenaline diffusing from the blood to the synaptic cleft may cause the desired action. Other explanations may be relevant in combination.
In order to test this hypothesis, other NET inhibitors were tested, such as desipramine and imipramine, which both are known to be NET inhibitors. It was shown that similar results were obtained by these tricyclic antidepressants. However, cocaine has a much smaller half-life time of about 1 hour while imipramine has a half-life time of 12 hours and desipramine has a half-life time of 30 hours. It was also shown that Venlafaxine (half-life time of 5 hours) had a similar effect. Thus, it seems that NET inhibition is at least desirable in order to potentiate the effect of blood circulation noradrenaline.
The conclusion is that a combination of NET inhibitors and noradrenaline would produce a synergetic effect in a brain dead, respirated body, in order to maintain or increase the vascular resistance and potentiate the effect of blood circulating noradrenaline.
At least a combination of noradrenaline and tricyclic antidepressants (including cocaine) would have the synergistic effect.
The same substances also have influence upon the action of adrenaline in the brain-dead, respirated body. A hypothesis is that the tricyclic antidepressants have similar effect on beta-receptors as has cocaine, for example to prevent down regulation of beta adrenergic cardiac receptors (BAR), i.e. a reduction of BAR density, see above.
Typical NET inhibitors are the following substances:
Tertiary Amine Tricyclics, such as: Amitriptyline (ELAVIL®), Clomipramine (ANAFRANIL®), Doxepin (ADAPIN®, SINEQUAN®), Imipramine (TROFANIL®), Trimipramine (SURMONTIL®);
Secondary Amine Tricyclics, such as: Amoxapine (ASENDIN®); Desipramine (NORPRAMIN®); Maprotinile (LUDIOMIL®); Nortriptyline (PAMELOR®); Protriptyline (VIVACTIL®);
Venlafaxin (EFFEXOR®); Atomexetine (WELLBUTRIN®); Duloxetine (CYMBALTA®); Mirtacapine (REMERON®); Norclomipramine; Oxaprotiline; Lofepramine, Reboxetine, Maprotiline, Nomifensine, Doxepin, Mianserin, Viloxazine, Mirtazapine, Nisoxetine and cocaine.
The potency seems to be highest for Desipramine, Protriptylin and Norclomipramine.
In one embodiment, cocaine (benzoylmethyl ecgonine) has been used. Cocaine acts as a NET inhibitor of noradrenaline and dopamine. The neuronal terminals will be protected from the high systemic levels of catecholamines. The level of catecholamines in the circulating blood may be maintained by infusion of small amounts of adrenaline and/or noradrenaline. Thus, the neuronal action will be preserved in spite of exposure for high levels of circulating catecholamines both during the “storm” and subsequently during the next 24 hours before harvesting of the organs. By the addition of adrenaline and/or noradrenaline, the sympathetic and parasympathetic tones may be maintained, preventing for example uncontrolled vasodilatation and tachycardia.
Cocaine and NET inhibitors may also or alternatively act via further mechanisms not known today, and may have a beneficial effect for preserving organs before harvesting in a brain dead, respirated body.
Cocaine analogues may operate in the same way. Analogues may be any analogue as defined above. It is believed that it is the stimulant effect of cocaine that is active. Thus, cocaine analogues mean cocaine analogues with stimulating effect.
Cocaine-analogues with both stimulant & local anesthetic effects are: Dimethocaine or larocaine (DMC) ((3-diethylamino-2,2-dimethylpropyl)-4-aminobenzoate); and 3-(p-Fluorobenzoyl)tropane ((1R,5S)-(8-methyl-8-azabicyclo[3.2.1]octan-3-yl)-4-fluorobenzoate).
Cocaine-analogues for stimulant effects with local anesthetic effects removed are: 3-CIT (methyl (1R,2S,3S,5S)-3-(4-iodophenyl)-8-methyl-8-azabicyclo[3.2.1]octane-2-carboxylate); β-CPPIT (3β-(4′-chlorophenyl)-2β-(3′-phenylisoxazol-5′-yl)tropane); FE-β-CPPIT (N-(2′-fluoroethyl)-3β-(4′-chlorophenyl)-2β-(3′-phenylisoxazol-5′-yl)nortropane); FP-β-CPPIT (N-(3′-fluoropropyl)-3β-(4′-chlorophenyl)-2β-(3′-phenylisoxazol-5′-yl)nortropane); Altropane (methyl (1R,2S,3S,5S)-3-(4-fluorophenyl)-8-[(E)-3-iodoprop-2-enyl]-8-azabicyclo[3.2.1]octane-2-carboxylate); Brasofensine ((E)-1-[(1R,2R,3S,5S)-3-(3,4-dichlorophenyl)-8-methyl-8-azabicyclo[3.2.1]oct-2-yl]-N-methoxymethanimine); CFT (methyl (1R,2S,3S,5S)-3-(4-fluorophenyl)-8-methyl-8-azabicyclo[3.2.1]octane-2-carboxylate); Dichloropane (methyl (1R,2S,3S,5S)-3-(3,4-dichlorophenyl)-8-azabicyclo[3.2.1]octane-2-carboxylate); Difluoropine (methyl (1S,2S,3S,5R)-3-[bis(4-fluorophenyl)methoxy]-8-methyl-8-azabicyclo[3.2.1]octane-2-carboxylate); Ioflupane (123I) (methyl (1R,2S,3S,5S)-3-(4-iodophenyl)-8-(3-fluoropropyl)-8-azabicyclo[3.2.1]octane-2-carboxylate); Nocaine (methyl (3R,4S)-4-(4-chlorophenyl)-1-methylpiperidine-3-carboxylate); Tesofensine ((1R,2R,3S,5S)-3-(3,4-dichlorophenyl)-2-(ethoxymethyl)-8-methyl-8-azabicyclo[3.2.1]octane); Troparil (methyl (1R,2S,3S,5S)-8-methyl-3-phenyl-8-azabicyclo[3.2.1]octane-2-carboxylate); Tropoxane (methyl (1R,2S,3S,5S)-3-(3,4-dichlorophenyl)-8-oxabicyclo[3.2.1]octane-2-carboxylate); (−)-Methyl-1-methyl-4β-(2-naphthyl)piperidine-3β-carboxylate (methyl (3S,4S)-1-methyl-4-naphthalen-2-ylpiperidine-3-carboxylate); PIT (2-propanoyl-3-(4-isopropylphenyl)-tropane); PTT (2β-Propanoyl-3β-(4-tolyl)-tropane); RTI-121, IPCIT (propan-2-yl (1R,2S,3S)-3-(4-iodophenyl)-8-methyl-8-azabicyclo[3.2.1]octane-2-carboxylate); RTI-126 ((1R,2S,3S,5S)-8-methyl-2-(1,2,4-oxadiazol-5-methyl)-3-phenyl-8-azabicyclo[3.2.1]octane); RTI-150 (cyclobutyl (1R,2S,3S,5S)-8-methyl-3-(4-methylphenyl)-8-azabicyclo[3.2.1]octane-2-carboxylate); RTI-336 ((1R,2S,3S,5S)-8-methyl-2-(3-(4-methylphenyl)isoxazol-5-yl)-3-(4-chlorophenyl)-8-azabicyclo[3.2.1]octane); WF-23 (2β-propanoyl-3β-(2-naphthyl)-tropane); WF-33 (2α-(propanoyl)-3β-(2-(6-methoxynaphthyl))-tropane).
The use of a cocaine analogue with the stimulating effect removed and including a local anesthetic effect cannot be used for the purpose of the present embodiments. Lidocaine is a typical example. However, infusion of Lidocaine will result in vasodilatation and a lowering of the blood pressure. It is expected that other local anesthetic agents similar to Lidocaine will produce the same blood pressure lowering effect.
It has been found that by using a NET inhibitor, such as cocaine or a cocaine analogue (stimulating) or a tricyclic antidepressant, it is possible to maintain a brain-dead, heart-beating, respirated donor for 24 hours, with substantial maintenance of organ viability, by intravenous injection of the NET inhibitor and noradrenaline.
In particular, the heart will benefit by the NET inhibitor, which seems to decrease the cardiac irritability.
In addition, it has been found that pulmonary edema may decrease by the use of a NET inhibitor. This will improve the result of subsequent pulmonary transplantation.
By further addition of small amounts of a vasopressor agent, the operation of the kidney can be maintained and the outcome of kidney transplantation is expected to improve.
The same is true for the liver and other organs, such as pancreas, intestines, etc. This may be caused by the improved cardiovascular stability obtained.
The body is provided with proper respiratory ventilation to keep the partial pressures of oxygen and carbon dioxide at suitable levels. Normally the brain dead body has no spontaneous respiration, which means that active ventilation is required. Such ventilation may take place in any manner previously known, for example by a respirator, by external compression of thorax, by manual or mechanical means, etc.
The body is also provided with an infusion solution for maintaining fluid balance. The kidneys produce urine at a desired output level of at least 1.0 ml/kg/hour. Thus, a fluid, such as Kreb's Ringer's solution, is infused at a rate of about 1 to 5 ml/kg/hour to compensate for kidney output, sweat and fluid losses during respiration.
The composition may further contain additional components such as cortisone, thyroxin (T4), insulin, triiodotyronine (T3), a vasopressor agent, such as arginine vasopressin, desmopressin or Minirin, and methylprednisolone (cortisone).
In order to avoid diabetes insipidus, it may be proper to add desmopressin already as early as possible, for example a bolus at the start of the intervention and then a normal continuous dose as produced by the body. Desmopressin may be titrated in dependence of the urine output, in order to maintain the goal of for example 1.0 ml/kg/hour. Since the urine output immediately after the catecholamine storm is very small or even non-existent, it may be required to add a Diuretic agent, such as Furosemide (LASIX®) in order to start urine production.
In one example the composition comprises the NET inhibitor, such as cocaine, and in addition adrenaline, noradrenaline, cortisone, thyroxin, triiodotyronine, and desmopressin.
The ratio between the NET inhibitor:noradrenaline may be about 1:1.
In some embodiments, the adrenaline and/or noradrenaline may be partly or entirely replaced by an equivalent substance. For example, phenylephrine is an alpha-1-agonist and may replace noradrenaline. It seems that phenylephrine is about 5 times less potent as noradrenaline.
Dopamine may be added in quantities less than about 0.01 mg/kg/min.
The embodiments also relate to an infusion solution comprising the composition as defined above dissolved in a pharmaceutical acceptable medium. Examples of acceptable mediums are physiological sodium chloride solution, Hartmann's solution and Ringer's (acetate) solution. Since the added volume is very small, in the range of 1.7 ml/hour (=0.04 ml/kg/hour), the ingredients may be dissolved in sterile, non-ionic water, i.e. pure H2O.
The final amounts of the different components, which may be present in the infusion solution of a volume of 50 ml, are about 0.1 to about 10 mg of noradrenaline, for example 1 mg, 0.1 to about 10 mg of adrenaline, such as 1 mg, 0.1 to about 10 mg of the NET inhibitor, such as 1 mg. The other components, which may be present, may be in an amount of about 0.05 to about 3 mg of triiodotyronine, T3, about 100 to about 1000 mg hydrocortisone, insulin and desmopressin.
The following ingredients: 1 mg (1 ml) adrenaline, 1 mg (1 ml) noradrenaline, 0.3 mg (3 ml) T3, 300 mg (3 ml) cortisone, 36 mg (9 ml) Minirin and 1 mg (3 ml) cocaine were dissolved in 50 ml physiological sodium chloride solution. The solution was added to the brain-dead, heart-beating cadaver of a pig with a weight of 40 kg, by intravenous infusion at an initial rate of 1.7 ml/hour, which was subsequently decreased in a dose dependent manner in order to maintain the mean arterial pressure MAP above about 60 mmHg. The infusion rate could be reduced to about 0.4 ml/hour over 24 hours.
In order to maintain blood volume, Macrodex replacement fluid was added at 100 ml/hour (2.5 ml/kg/hour) to support a urine output of about 1.9 liters over 24 hours. The rest of the added fluid is removed from the body via lung respiration and sweat.
In order to counteract any tendency to form edema or any vascular instability, it may be proper to add dextran to the replacement fluid, such as Dextran 40 or Dextran 70.
For reducing the risk of diabetes insipidus, a bolus of 12 mg Minirin was given at the start of the treatment.
The cadaver showed no significant signs of organ dysfunction. The heart, lungs, liver, kidney, and other organs were proper for transplantation purpose.
The blood pressure in an experiment with the above solution at a pig with a weight of 40 kg is shown in
After 14 hours, the infusion rate was increased, resulting in a clear and immediate increase of blood pressure. The infusion rate was then lowered to obtain base-line pressures. As is shown in
During the harvesting of the organs after 24 hours, the infusion of the solution was again increased to baseline of 1.7 ml/hour during half an hour before harvesting and maintained until all organs were removed.
An infusion rate of 1.7 ml/hour corresponds to an infusion of 0.015 μg/kg/min of adrenaline and noradrenaline, which is less than the normal production rate of the adrenal medulla, which may be about 0.05 μg/kg/min. Such small infusion rate into the blood is believed to be tolerated by the organs and the system of the brain dead body.
A similar experiment was conducted wherein cocaine was replaced by desipramine. 3 mg of desipramine was added instead of 1 mg cocaine to 50 ml of physiological sodium chloride solution. In addition 1 mg of adrenaline and 1 mg of noradrenaline was included in the solution.
The desipramine solution was added to a pig similar to the pig in Experiment 1 at time instance 21 hours. The infusion rate was 1.7 ml/hour. The infusion rate was increased to 3.2 ml/hour at time instance 22 hours and the blood pressure started to rise. At time instance 26 hours, the infusion rate was decreased to 2.5 ml/hour. At time instance 28 hours, the infusion rate was decreased to 1.7 ml/hour.
The blood pressure during the time interval from 17 hours to 35 hours is shown in
As can be seen, the brain-dead body answered on the infusion of desipramine by increasing the blood pressure from a mean pressure of about 40 mmHg to a mean pressure of 80 mmHg. When the infusion rate was decreased, the blood pressure went down to about 60 mmHg, but never decreased further. It is believed that desipramine maintained its NET inhibitory effect over a long time because of its long half-life time. Thus, desipramine was active even when the infusion of desipramine was decreased and for several hours thereafter.
A similar experiment was conducted wherein cocaine was replaced by imipramine. In this experiment, adrenaline and noradrenaline was added at a constant rate of 0.4 ml/hour. At time instance 21 hours, a bolus of 2 mg cocaine was added and resulted in an increase of the blood pressure. The effect of the bolus of cocaine ceased after about 3 hours and a bolus of imipramine was added at time instance 24.5 hours. The bolus of imipramine resulted in an increase of blood pressure from about 80 mmHg to about 100 mmHg. This is shown in the diagram of
The infusion solution comprising the substances mentioned above is added to the blood circulation intravenously. The addition takes place by means of an electronically controlled infusion pump as shown in
In another embodiment, the volume of infusion solution is about 100 ml, which will be sufficient for a large patient of up to 100 kg during 24 hours. In this case, the entire procedure may take place fully automatically, without any need for manual intervention.
Each bag may comprise one or several of the ingredients mentioned above. For example, bag 31 may comprise adrenaline, bag 41 may comprise noradrenaline, bag 51 may comprise cocaine or a NET inhibitor, bag 61 may comprise Minirin, bag 71 may comprise a mixture of hormones, such as T3, T4, cortisone, etc., and bag 81 may comprise an infusion solution such as Kreb-Ringer solution, which is an isotonic infusion solution comprising glucose.
Each pump may be controlled by a computer 90 as shown in
The computer may operate according to several strategies. One strategy may be to add cocaine at a rate which is proportional to the addition rate of noradrenaline. Another strategy may be to add cocaine in proportion to the addition rate of adrenaline or the sum of adrenaline and noradrenaline. A further strategy would be to add cocaine in a constant rate independent of the addition of adrenaline and/or noradrenaline.
If another NET inhibitor is used having a long half-life, a bolus at the start of the intervention would be adequate, followed by a smaller bolus after six hours etc. The effect of the bolus will be present during a long time after the bolus injection and the hemodynamic stability can be controlled by small amounts of adrenaline and noradrenaline.
The treatment or intervention should start as soon as possible after determination of brain death. There may be time delays between the actual death and the time when the condition of brain death is determined and such time delays should be as short as possible. The treatment may start with a bolus injection, especially if there is a substantial time delay and the blood pressure already is below about 50 mmHg.
The treatment is continued as until it is determined that organ harvesting should be performed. Shortly before harvesting, the infusion is increased to prepare the organs for maintaining as proper condition as possible during harvesting and the time immediately following harvesting. The treatment is performed from immediately after brain death until organ harvesting.
The inventor has performed more than 20 experiments with pigs and using cocaine in combination with adrenaline and noradrenaline. In each case it has been possible to maintain the blood pressure at a constant level of for example 70 mmHg from the initiation of the intervention and over 24 hours. Usually, the dose required during the first hours has to be reduced, for example from 1.7 ml/hour during the first six hours and down to 0.4 ml/hour during the last six hours. However, there are large individual differences. By this action, the blood pressure immediately after the catecholamine storm can be maintained at a sufficient level, thereby avoiding a blood pressure below 40 mmHg, which normally occurs after the catecholamine storm if no intervention is performed.
In many cases, it is not required to control all parameters and use six (or more) individually controlled supplies. One versatile combination would be to have adrenaline and cocaine in bag 31, noradrenaline and cocaine in bag 41, Minirin in bag 51, infusion solution in bag 61 and the other ingredients in bag 71, and excluding bag 81.
A further embodiment would include adrenaline, noradrenaline and cocaine in bag 31, further ingredients in a second bag 41 and infusion solution in a third bag 51.
Alternatively, both the infusion solution, which comprises a NET inhibitor, and the replacement fluid may be arranged in the same bag, which in this case should have a volume of about 2.5 liter.
In the claims, the term “comprises/comprising” does not exclude the presence of other elements or steps. Furthermore, although individually listed, a plurality of means, elements or method steps may be implemented by e.g. a single unit. Additionally, although individual features may be included in different claims or embodiments, these may possibly advantageously be combined, and the inclusion in different claims does not imply that a combination of features is not feasible and/or advantageous. In addition, singular references do not exclude a plurality. The terms “a,” “an,” “first,” “second,” etc., do not preclude a plurality. Reference signs in the claims are provided merely as a clarifying example and shall not be construed as limiting the scope of the claims in any way.
Although the present invention has been described above with reference to specific embodiment and experiments, it is not intended to be limited to the specific form set forth herein. Rather, the invention is limited only by the accompanying claims and, other embodiments than those specified above are equally possible within the scope of these appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 0802678-3 | Dec 2008 | SE | national |
This application is a continuation of U.S. application Ser. No. 13/142,727, filed Jun. 29, 2011, which is a national stage application of International Appl. PCT/SE2009/000541, filed Dec. 30, 2009, which claims the benefit of provisional U.S. Application No. 61/210,444, filed Mar. 19, 2009, and which claims priority of Swedish Patent Appl. No. 0802678-3, filed Dec. 30, 2008, all of which are hereby incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| 61210444 | Mar 2009 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 13142727 | Jun 2011 | US |
| Child | 15241318 | US |
