On 2018 Jan 15, Hauke Fürstenwerth commented:

Blaustein’s attemps to disqualify Vogeser’s studies started with the false assertion that the analytical protocol did not assess the degree of recovery of the extraction step [1]. Now he presents imaginative speculations about unknown compounds and on a low level of noise in Vogeser’s chromatograms. Blaustein’s defamatory accusations are unfounded. They do not change the fact that Ouabain can not be detected in human serum by using state-of-the-art analytical methods. In the e-pub-first version of his article, Blaustein reports that Clin Chim Acta has refused to retract the Vogeser publication, with good reason. In the assessment of experts in analytical chemistry there is no doubt on the validity of Vogeser’s measurements.

[1] http://hyper.ahajournals.org/content/64/4/680/tab-e-letters

On 2018 Jan 13, Mordecai P Blaustein commented:

Response to Dr. Füerstenwerth:

The case for a ouabain-Na pump endocrine system has been laid out in [1] and my previous response to Dr. Fürstenwerth. All the original reports are cited so that readers can verify my statements.

I must, however, refute Fürstenwerth’s false claim that I made an “unfounded accusation of data manipulation” by stating that Baecher et al. [2] “’edited’ their raw data”. Fürstenwerth apparently has not read Vogeser and Baecher’s Letter to the Editor [3] in which they admit that “In… Fig. 2 of our article ([2])… at a retention time (RT)… of… 5.0 min… the trace signal is broken… This inconsistency was introduced by editing the… (mass spectrum) raw data.” They show (Fig. 2, top, in [3]) that they originally (Fig. 2, top, in [2]) edited out an ion current peak at 4.99 min, and they present a second example (Fig. 1, top, in [3]) in which a similar peak is seen at that same RT (4.98 min) (see [4] Data Supplement). They do not mention the other 28 plasma samples they tested [2]; how many of them exhibited the same peak? Why didn’t they show/describe all their data? (The “broken” trace signal in Fig. 2 of [2] is very difficult to see on the original journal page. Dr. Hamlyn suspected that the spectrum was 'unusually flat'. When he enlarged the image he discovered the discontinuity.) We suggest [4] that the ion current peak at the 5.0 min RT, which has the same mass/charge ratio as ouabain, may correspond to the more polar of two ouabain isomers that have previously been described [5, 6]. Other flaws in the Baecher et al. study [2] are discussed elsewhere [1, 4, 7].

References:

[1] Blaustein MP, 2018

[2] Baecher S, 2014

[3] Vogeser M, 2015

[4] Hamlyn JM, 2016

[5] Jacobs BE, 2012

[6] Hamlyn JM, 2014

[7] Blaustein MP, 2015

On 2018 Jan 12, Hauke Fürstenwerth commented:

Final response to Dr. Blaustein

<p>@ 1: yes, S. kombé contains a mixture of steroids, but contrary to Blaustein’s assertion no ouabain. Kirk discovered the effects of k-strophanthin.</p>

<p>@ 2: yes, inactivating mutation of the mouse alpha-2 Na+ pump ouabain binding site has physiologic consequences. This is no evidence that the endogenous inhibitor of the NaK-pump is ouabain.</p>

<p>@ 3: unfounded accusation of data manipulation (”edited their raw data”, “scientific misconduct”) does not refute the fact that in various laboratories it has not been possible to detect ouabain in human serum with highly specific analytical methods.</p>

<p>@ 4: With the admission that ”ouabain can be expected to have both beneficial and … detrimental effects” Blaustein refutes assertions he has made in his article: “ouabain is a key factor in the pathogenesis of hypertension and heart failure" and “ouabain and its receptor site participate in the pathogenesis of hypertension, cardiac hypertrophy and HF“. Provided ouabain is the endogenous inhibitor of the NaK-pump that at low levels has positive but at elevated levels has detrimental effects, then it remains puzzling why infusion of plant derived ouabain (elevating serum concentration!) in clinical practice lowers blood pressure and is life-saving in acute heart failure. (Oh yes, common sense can be annoying.)</p>

<p>@ 5: With highly specific analytical methods it is not possible to detect “endogenous ouabain”. (Blaustein admits that there is no ”convenient EO assay.”) However, concentrations of plant derived ouabain can be measured even in extreme low concentrations. From such measurements the therapeutic levels of ouabain serum concentrations are known and have been validated by decades of clinical experience. Thus, effective therapeutic dosing of ouabain is a well established procedure.</p>

<p>@ 6: The sophisticated total syntheses of ouabain are high-lights in synthetic chemistry. These masterpieces allow the preparation of a few mg on laboratory scale, but they are not suited for large scale production of ouabain.</p>

Finally, I do agree with Blaustein that in science many notions have landed in the trash bin of history. I dare to predict that ”endogenous ouabain” , too, will suffer that fate.

On 2018 Jan 12, Mordecai P Blaustein commented:

Response to Dr. Fürstenwerth

I thank Dr. Fürstenwerth for his comments about my article. His exuberant advocacy for the clinical use of ouabain is refreshingly entertaining. As he states, however, his views are based largely on “applying common sense”; he appears to ignore the experimental method and actual data. (“Common sense” also led to such ideas as, “the earth is flat,” and “the sun revolves around the earth” – notions that landed in the trash bin of history.)

1. Fürstenwerth correctly asserts that k-strophanthin is the predominant cardenolide extracted from Strophanthus kombé, but this plant produces a mixture of related steroids [1].

2. He states that the “endogenous ouabain-Na+ pump endocrine system… is… wishful thinking.” Data from multiple laboratories, summarized in my article, demonstrate that an inactivating mutation of the mouse alpha-2 Na+ pump ouabain binding site, or infusion of anti-ouabain antibodies to immuno-neutralize endogenous ouabain (EO) in rats, induces a clear phenotype. This loss of EO-Na+ pump interaction is manifested by specific disturbances of (e.g.) behavior and learning, exercise endurance, fetal development and basal blood pressure. In my view, these data trump Fürstenwerth’s “common sense”.

3. He claims that “There is no endogenous ouabain.” Has he read (or understood) the articles listed in Table 2A? Rather than relying on “common sense”, I prefer the mass spectra and NMR spectra published by such distinguished chemists/biochemists as Prof. Wilhelm Schoner [2], Prof. Tadashi Inagami [3], and Prof. Koji Nakanishi [4], a member of the National Academy of Sciences USA and one of the world’s leading natural product chemists. Moreover, the very detailed original mass spectroscopy report included all the original, rigorous purification data [5-7]. In contrast, the few investigators who were unable to detect EO (Table 2C) cut methodological corners (see text and [8]) and even “edited” their raw data [9,10] (and see [8]).

4. Fürstenwerth claims that my review “neglects” the “beneficial” effects of ouabain and “does not discuss (the)... obvious contradictions” that “ouabain lowers blood pressure, (but also) produces hypertension”. His statement is not true. Table 3 shows that mutation (inactivation) of the alpha-2 Na+ pump ouabain binding site elevates basal blood pressure; this implies that EO is normally needed to help keep blood pressure low (i.e., ‘normal’). On the other hand, Yuan et al. [11] were just the first of numerous investigators to show that prolonged, high ouabain levels elevate blood pressure. Like all hormones, ouabain can be expected to have both beneficial and, if greatly elevated for a prolonged period, detrimental effects (see Fig. 4 and pages C14 and C16 of my article).

5. I do not dispute Fürstenwerth’s assertion that the “decisive factor is the (ouabain) serum concentration”. But, in that case, given the aforementioned data, his opposition to my call for “solid information” about plasma EO/ouabain levels before and during ouabain therapy makes no sense. Drug treatment based simply on “common sense” must give way to effective therapeutic dosing that utilizes all the available scientific information to optimize treatment and patient safety.

6. Finally, Fürstenwerth states that “production of Strophanthus glycosides is… restricted to collection of wild plants.” This is not true. The complete chemical synthesis of ouabain was achieved by Deslongchamps [12] and a more concise method has now been developed [13].

In conclusion, as Withering wrote in 1785 [14], “After all, in spite of opinion, prejudice or error, Time will fix the real value upon this discovery, and determine whether I have imposed upon myself and others, or contributed to the benefit of science and mankind”.

References:

[1] Jacobs & Hoffman, J Biol Chem 69: 153-163, 1926.

[2] Schneider R, 1998

[3] Tamura M, 1994

[4] Kawamura A, 1999

[5] Hamlyn JM, 1991

[6] Ludens JH, 1991

[7] Mathews WR, 1991

[8] Hamlyn JM, 2016

[9] Baecher S, 2014

[10] Vogeser M, 2015

[11] Yuan CM, 1993

[12] Reddy MS, 2009

[13] Renata H, 2015

[14] Withering, “An Account of the Foxglove and Some of its Medical Uses”, M. Swinney for G.G.J. and J. Robinson, Birmingham, 1785.

On 2018 Jan 12, Mordecai P Blaustein commented:

None

On 2018 Jan 08, Hauke Fürstenwerth commented:

the mistreated gift from paradise

In the final version of his article Blaustein again reveals his ignorance of the history of Ouabain and Strophanthus glycosides. It is not true that Ouabain is found in Strophanthus kombé. The glycoside occurring in S. kombé is k-strophanthin. Ouabain is found in both Acokanthera ouabaio and Strophanthus gratus. Herman Thoms isolated the pure glycosides from S. kombé and S. gratus in 1904 and has unambiguously assigned them with the names k- and g-strophanthin [1].

Based on the work of Thomas Fraser, Burroughs, Wellcome & Co in 1886 introduced a S. kombé extract called "Tincture of Strophanthus". This was sold at seven shillings per ounce. In America, E.R. Squibb and Sons was one of the first suppliers of Strophanthus preparations. Particularly popular was a chocolate coated tablet of a mixture of Digitalis and Strophanthus extracts, which was sold at 16 cents per one hundred pieces [2]. In 1889, Boehringer Mannheim introduced pure k-strophanthin to the market. In cooperation with Albert Fraenkel Boehringer in 1907 introduced a solution of k-strophanthin for intravenous administration under the brand name “Kombetin”.

In 1904 E. Merck, Darmstadt, commercialized a standardized solution of pure g-strophanthin as "g-Strophanthin crystallisatum after Thoms". In 1906, also Kali-Chemie began marketing a g-strophanthin solution under the trade name “Purostrophan”. In the following years, several suppliers offered Strophanthus glycosides preparations for oral and intravenous use. In contrast to Blaustein's assertion orally administered ouabain products over the decades of their use have been given as standard medication to millions of patients. The database of the German Institute for Medical Documentation and Information records more than 20 orally administered ouabain preparations that were used in Germany after 1950. Decades of clinical experience with dozens of ouabain based preparations (i.e. treatment of millions of patients) can not be disqualified as „anecdotal“.

Blaustein's core hypothesis is that “ouabain is a key factor in the pathogenesis of hypertension and heart failure". At the same time he states that ouabain is “equipotent to digoxin” and has been used “for acute iv administration in heart failure emergencies“. By applying common sense, it can be ruled out that a substance that has been used successfully for decades as an emergency drug in the treatment of heart failure will cause heart failure. Equally excluded is that ouabain, which in clinical practice lowers blood pressure, produces hypertension. Already Fraser had pointed out that “strophanthin increases the action of the heart without raising blood pressure.” Blaustein does not discuss these obvious contradictions nor does he suggest an explanation. He as well neglects current reports on cardio protection induced by ouabain as well as conclusions by Lijune Liu and co-workers that ouabain can be beneficial to various stages of heart failure.

Based on all available data it can be ascertained that the mutually exclusive effects of plant derived ouabain and the inhibitor of the Na/K-ATPase observed in mammalian tissues do not support the hypothesis that this inhibitor is identical with ouabain, but favor the interpretation that “endogenous ouabain” is something different. Hence, Blaustein's request to establish "solid information about the normal plasma EO level under a variety of conditions" is unfounded. There is no endogenous ouabain.

African healers have long recognized the medical value of Strophanthus extracts. The medical application relied on alcoholic decotions made by steeping roots in a fermented, alcoholic beverage. The resulting bitter tasting solution would be taken in small sips over a period of days or weeks [2]. The healers knew that the effect of Strophanthus as a potent plant with both healing and highly toxic capabilities, crucially depends on the method of preparation of the drug. In 1971 this observation found a decisive scientific confirmation. Lindenbaum et al published findings that different batches of digoxin from the same manufacturer resulted in different serum concentrations [3]. This publication and subsequent studies lead to the transformation of the art of galenics from a trial-and-error exercise into a scientific discipline. Contrary to Blaustein's assertion, today we know from progress in pharmacology and galenics that absolute bioavailability is not decisive for the therapeutic effect. The only decisive factor is the serum concentration, which enables a sustained therapeutic effect. This is achieved by a correspondingly optimized galenic formulation of the active substance. Different formulations require different dosages to produce the same serum concentration. This is the explanation for the different concentrations of ouabain preparations cited by Blaustein. Contrary to Blaustein's assertion the therapeutic serum concentrations of ouabain are well known: 0.5 ng/ml in steady-state after iv administration and 0.4-0.9 ng/ml on oral administration of suitable galenic preparations.

Blaustein argues on the basis of outdated knowledge that does not take into account the effects of galenics. Today drugs such as Aliskiren, whose absorption rate is about 3%, will not be rejected just because the absorption rate is too low. Aliskiren’s therapeutic effects derive from sufficiently high serum concentrations, not from the total amount absorbed. The same is true for drugs like Nisoldipine (5%), Dabigatranetextilat (6.5%), or Ramipril (15%), which have absorption rates comparable to that of ouabain. For ouabain, absorption rates of up to 10% have been measured.

Blaustein falsely assumes that Ouabain has been withdrawn from the market because there has been a death following intravenous administration. The anecdotal evidence he refers to is a patient with multiple co-morbidities. It is outright medical malpractice to inject 0.75 mg ouabain in such a patient when the standard dose should not exceed 0.25 mg.

Ouabain preparations are no longer available because no company was willing to fund the required clinical trials. The historical preference of Digitalis glycosides over Strophanthus glycosides is due to two factors. 1. Digitalis glycosides can be produced at low cost on an industrial scale from commercial Digitalis plantations. The production of Strophanthus glycosides is and was restricted to collection of wild plants and is correspondingly expensive. 2. Cardiac glycosides were used with the aim of strengthening the contraction force of the heart muscle. Since digitalis glycosides have a stronger inotropic effect than Strophanthus glycosides, the former were preferred. Additionally, false ideas about the importance of galenics have certainly contributed to the uncertainty of clinicians.

For the locals in Africa, Strophanthus was poison and remedy in one. In the mythology of the tribe of the Wilé in Upper Volta, this plant was sent from paradise to the earth to heal or punish people according to their merit [4]. Hence, it is an ethical obligation when studying Strophanthus glycosides to apply generally accepted principles in science. Otherwise hubris and personal vanity will hinder finding the truth. Mordecai P. Blaustein breaks with this generally accepted principles in science. He ignores ideas and data that don’t fit his preconceptions and neglects conflicting results that don’t support his hypotheses. Blaustein’s narrative about the construction of an "endogenous ouabain-Na+ pump endocrine system" lacks a necessary critical perspective. It is guided by wishful thinking and not by facts.

References

[1] https://link.springer.com/chapter/10.1007/978-3-662-40381-5_7

[2] Osseo-Asare AD, Bitter roots: the search for healing plants in Africa, The University of Chicago Press, 2014

[3] Lindenbaum J, 1971

[4] Leuenberger H, Gesund durch Gift, Deutsche Verlagsanstalt Stuttgart, 1972

On 2017 Dec 13, Hauke Fürstenwerth commented:

None

On 2017 Nov 15, Hauke Fürstenwerth commented:

None

On 2017 Nov 14, Mordecai P Blaustein commented:

The topic of "ouabain as a therapeutic agent" is discussed in the print version of this article ("The Pump, the Exchanger and the Holy Spirit..."). The print version will be published in the December 2017 issue of Am J Physiol Cell Physiol.

On 2017 Nov 06, Hauke Fürstenwerth commented:

Are clinical experiences not relevant?<br> In medical research, decisive results are obtained by clinical experiences. Hence, new hypotheses need to be checked for clinical findings and observations. Ouabain and the related Strophanthus glycoside k-strophanthin by default have been used for more than a century to treat heart diseases. Cymarin and convallatoxin have also been used. As early as 1904, a standardized solution of pure ouabain was commercialized by E. Merck, Darmstadt as “g-Strophanthin crystallisatum nach Thoms”. This ouabain solution was used both intravenously [7] and orally administered in the treatment of heart diseases. In 1909, the French physician Henri Vaquez introduced the intravenous application of ouabain (“Ouabain-Arnaud”) in France. In World War I medical personnel in the German army by order of the ambulance corps exclusively used ouabain solutions to treat heart failure [4]. The therapeutic profile and the disease profiles for which the use of Strophanthus glycosides is appropriate are documented in many reports on clinical experiences and have been summarized in numerous reviews, preferably in the German literature [10]. As early as the first half of the 20th century distinguished scientists such as Albert Fraenkel, University of Heidelberg, and Ernst Edens, University of Dusseldorf, have published monographs [8,5] that document in detail the clinical effects of Strophanthus glycosides. In textbooks ouabain has been praised as "the biggest advance in cardiac therapy since Withering in 1785" [6]. Decades of clinical experience with ouabain provide a yardstick by which all research results and hypotheses related to ouabain have to be measured. Observations at the bedside are more meaningful than speculative hypotheses based on experimental research.

In his article Mordecai P. Blaustein gives no reference to the comprehensive literature on clinical experience with ouabain. Although he concludes from his hypotheses that “ouabain and its receptor site participate in the pathogenesis of hypertension, cardiac hypertrophy and HF“ he does not even mention the fact that ouabain has been used successfully in medical therapy of heart failure.

Contrary to well-documented positive clinical experience in the treatment of heart disease with ouabain, Blaustein asserts that ouabain damages the cardio-vascular system. He neglects current reports on cardio protection induced by ouabain [13,15,19] as well as conclusions by Lijune Liu and co-workers that ouabain can be beneficial to various stages of heart failure [14]. Blaustein asserts that ouabain raises blood pressure in humans, but at the same time admits that ouabain increases blood pressure only in selected rodents strains, because the susceptibility to ouabain-induced hypertension is genetically-determined. Thus there is no evidence to suggest that ouabain is hypertensinogenic in humans. In clinical experience a reduction of high blood pressure in patients is observed on treatment with ouabain [9].

Blaustein asserts that in more than two centuries of clinical use of digoxin no hints have been found that digoxin is hypertensinogenic. However, it is common knowledge that Digitalis as well as Strophanthus glycosides in high enough concentration increase blood pressure [1,8]. The effects of cardiac glycosides are very sensitive to the applied dosage. Cardiac glycosides are prototypical examples of hormetic substances [10]. The hormetic nature of ouabain is also observed in the effect on signal transduction. According to the studies quoted by Blaustein in his article, low concentrations of ouabain activate signaling cascades, while high concentrations inhibit them.

Ouabain has been used in clinical application to treat digitalis intoxication in patients. Corresponding reports are documented as early as 1902. Recent in vitro and in vivo studies confirm this well-known clinical observation [16]. So contrary to Blaustein’s hypothesis that digoxin prevents negative effects of ouabain, in clinical practise ouabain has been shown to prevent damage from digoxin. It is a frequently reported observation that Strophanthus glycosides also work in patients in whom digitalis glycosides have no effect, see for example the publication of the renowned cardiologists Franz Groedel and Bruno Kisch [11].

The therapeutic effects of k-and g-strophanthin are largely identical, ouabain being slightly more potent than k-strophanthin [8,17]. In a double blind cross-over study Agostoni compared the effects of k-strophanthin and digoxin in 22 patients with advanced congestive heart failure [2]. K-strophanthin improved functional performance while digoxin failed to provide such results. Norepinephrine plasma level at rest was significantly lowered by k-strophanthin but not by digoxin.

Based on all available data it can be ascertained that the mutually exclusive effects of ouabain and the inhibitor of the Na/K-ATPase observed in mammalian tissues do not support the hypothesis that this inhibitor is identical with ouabain, but favor the interpretation that “endogenous ouabain” is something different.

Blaustein asserts that Hamlyn identified two ouabain isomers in rodent plasma that are absent from commercial (plant) ouabain. This assertion is not backed by the corresponding Hamlyn publication [12]. Therein Hamlyn reports the presence of several substances in plasma of pregnant rats that show immunoreactivity. Two substances are chromatographically slightly different from ouabain and have different mass spectra. Hamlyn does not provide any data for the elucidation of the chemical structure. The chemical structure of these products is unknown. So it is not justified to claim that these substances are isomers of ouabain.

Nor does the existence of these unknown compounds in plasma of rats suggest that endogenous ouabain is of animal origin. A comparison of substances found in unpurified plasma with purified ouabain - ie free from impurities - is meaningless. Provided that these substances will be identified by structural analysis as isomers of ouabain then it still has to be examined whether these substances are also found in Strophanthus or Acokanthera extracts.

References

[1] Abelmann WH, 1973<br> [2] Agostoni PG, 1994<br> [4] https://sites.google.com/a/aryapa.faith/iosifpravin/albert-fraenkel-ein-arztleben-in-licht-und-schatten-1864-1938-reihe-ecomed-biographien-3609162600

[5] Edens E, Die Digitalisbehandlung [Digitalis treatment] , Third edition, Berlin-München, Verlag Urban&Schwarzenberg, 1948

[6] Eichholtz F, Lehrbuch der Pharmakologie [Textbook of Pharmacology], fifth edition, Berlin und Heidelberg, Springer Verlag, 1947.

[7] Fleischmann P, Wjasmensky H. Ü̈ber intravenöse Strophanthintherapie bei Verwendung von gratus-Strophanthinum crystallisatum Thoms. Deutsche Medizinische Wochenschrift 35: 918–921, 1909

[8] https://books.google.de/books?id=iq-kBgAAQBAJ&printsec=frontcover&hl=de&source=gbs_ge_summary_r&cad=0#v=onepage&q&f=false

[9] https://doi.org/10.9734/BJMMR/2015/17042

[10] Fürstenwerth H, 2016

[11] https://doi.org/10.1016/S0025-7125(16)36725-6

[12] Jacobs BE, 2012

[13] Lagerstrom CF, 1988

[14] Liu L, 2016

[15] Morgan EE, 2010

[16] Nesher M, 2010

[17] PFEIFER E, 1960

[19] Wu J, 2015

On 2017 Nov 06, Hauke Fürstenwerth commented:

Are clinical experiences not relevant?<br> In medical research, decisive results are obtained by clinical experiences. Hence, new hypotheses need to be checked for clinical findings and observations. Ouabain and the related Strophanthus glycoside k-strophanthin by default have been used for more than a century to treat heart diseases. Cymarin and convallatoxin have also been used. As early as 1904, a standardized solution of pure ouabain was commercialized by E. Merck, Darmstadt as “g-Strophanthin crystallisatum nach Thoms”. This ouabain solution was used both intravenously [7] and orally administered in the treatment of heart diseases. In 1909, the French physician Henri Vaquez introduced the intravenous application of ouabain (“Ouabain-Arnaud”) in France. In World War I medical personnel in the German army by order of the ambulance corps exclusively used ouabain solutions to treat heart failure [4]. The therapeutic profile and the disease profiles for which the use of Strophanthus glycosides is appropriate are documented in many reports on clinical experiences and have been summarized in numerous reviews, preferably in the German literature [10]. As early as the first half of the 20th century distinguished scientists such as Albert Fraenkel, University of Heidelberg, and Ernst Edens, University of Dusseldorf, have published monographs [8,5] that document in detail the clinical effects of Strophanthus glycosides. In textbooks ouabain has been praised as "the biggest advance in cardiac therapy since Withering in 1785" [6]. Decades of clinical experience with ouabain provide a yardstick by which all research results and hypotheses related to ouabain have to be measured. Observations at the bedside are more meaningful than speculative hypotheses based on experimental research.

In his article Mordecai P. Blaustein gives no reference to the comprehensive literature on clinical experience with ouabain. Although he concludes from his hypotheses that “ouabain and its receptor site participate in the pathogenesis of hypertension, cardiac hypertrophy and HF“ he does not even mention the fact that ouabain has been used successfully in medical therapy of heart failure.

Contrary to well-documented positive clinical experience in the treatment of heart disease with ouabain, Blaustein asserts that ouabain damages the cardio-vascular system. He neglects current reports on cardio protection induced by ouabain [13,15,19] as well as conclusions by Lijune Liu and co-workers that ouabain can be beneficial to various stages of heart failure [14]. Blaustein asserts that ouabain raises blood pressure in humans, but at the same time admits that ouabain increases blood pressure only in selected rodents strains, because the susceptibility to ouabain-induced hypertension is genetically-determined. Thus there is no evidence to suggest that ouabain is hypertensinogenic in humans. In clinical experience a reduction of high blood pressure in patients is observed on treatment with ouabain [9].

Blaustein asserts that in more than two centuries of clinical use of digoxin no hints have been found that digoxin is hypertensinogenic. However, it is common knowledge that Digitalis as well as Strophanthus glycosides in high enough concentration increase blood pressure [1,8]. The effects of cardiac glycosides are very sensitive to the applied dosage. Cardiac glycosides are prototypical examples of hormetic substances [10]. The hormetic nature of ouabain is also observed in the effect on signal transduction. According to the studies quoted by Blaustein in his article, low concentrations of ouabain activate signaling cascades, while high concentrations inhibit them.

Ouabain has been used in clinical application to treat digitalis intoxication in patients. Corresponding reports are documented as early as 1902. Recent in vitro and in vivo studies confirm this well-known clinical observation [16]. So contrary to Blaustein’s hypothesis that digoxin prevents negative effects of ouabain, in clinical practise ouabain has been shown to prevent damage from digoxin. It is a frequently reported observation that Strophanthus glycosides also work in patients in whom digitalis glycosides have no effect, see for example the publication of the renowned cardiologists Franz Groedel and Bruno Kisch [11].

The therapeutic effects of k-and g-strophanthin are largely identical, ouabain being slightly more potent than k-strophanthin [8,17]. In a double blind cross-over study Agostoni compared the effects of k-strophanthin and digoxin in 22 patients with advanced congestive heart failure [2]. K-strophanthin improved functional performance while digoxin failed to provide such results. Norepinephrine plasma level at rest was significantly lowered by k-strophanthin but not by digoxin.

Based on all available data it can be ascertained that the mutually exclusive effects of ouabain and the inhibitor of the Na/K-ATPase observed in mammalian tissues do not support the hypothesis that this inhibitor is identical with ouabain, but favor the interpretation that “endogenous ouabain” is something different.

Blaustein asserts that Hamlyn identified two ouabain isomers in rodent plasma that are absent from commercial (plant) ouabain. This assertion is not backed by the corresponding Hamlyn publication [12]. Therein Hamlyn reports the presence of several substances in plasma of pregnant rats that show immunoreactivity. Two substances are chromatographically slightly different from ouabain and have different mass spectra. Hamlyn does not provide any data for the elucidation of the chemical structure. The chemical structure of these products is unknown. So it is not justified to claim that these substances are isomers of ouabain.

Nor does the existence of these unknown compounds in plasma of rats suggest that endogenous ouabain is of animal origin. A comparison of substances found in unpurified plasma with purified ouabain - ie free from impurities - is meaningless. Provided that these substances will be identified by structural analysis as isomers of ouabain then it still has to be examined whether these substances are also found in Strophanthus or Acokanthera extracts.

References

[1] Abelmann WH, 1973<br> [2] Agostoni PG, 1994<br> [4] https://sites.google.com/a/aryapa.faith/iosifpravin/albert-fraenkel-ein-arztleben-in-licht-und-schatten-1864-1938-reihe-ecomed-biographien-3609162600

[5] Edens E, Die Digitalisbehandlung [Digitalis treatment] , Third edition, Berlin-München, Verlag Urban&Schwarzenberg, 1948

[6] Eichholtz F, Lehrbuch der Pharmakologie [Textbook of Pharmacology], fifth edition, Berlin und Heidelberg, Springer Verlag, 1947.

[7] Fleischmann P, Wjasmensky H. Ü̈ber intravenöse Strophanthintherapie bei Verwendung von gratus-Strophanthinum crystallisatum Thoms. Deutsche Medizinische Wochenschrift 35: 918–921, 1909

[8] https://books.google.de/books?id=iq-kBgAAQBAJ&printsec=frontcover&hl=de&source=gbs_ge_summary_r&cad=0#v=onepage&q&f=false

[9] https://doi.org/10.9734/BJMMR/2015/17042

[10] Fürstenwerth H, 2016

[11] https://doi.org/10.1016/S0025-7125(16)36725-6

[12] Jacobs BE, 2012

[13] Lagerstrom CF, 1988

[14] Liu L, 2016

[15] Morgan EE, 2010

[16] Nesher M, 2010

[17] PFEIFER E, 1960

[19] Wu J, 2015

On 2017 Nov 14, Mordecai P Blaustein commented:

The topic of "ouabain as a therapeutic agent" is discussed in the print version of this article ("The Pump, the Exchanger and the Holy Spirit..."). The print version will be published in the December 2017 issue of Am J Physiol Cell Physiol.

On 2018 Jan 08, Hauke Fürstenwerth commented:

the mistreated gift from paradise

In the final version of his article Blaustein again reveals his ignorance of the history of Ouabain and Strophanthus glycosides. It is not true that Ouabain is found in Strophanthus kombé. The glycoside occurring in S. kombé is k-strophanthin. Ouabain is found in both Acokanthera ouabaio and Strophanthus gratus. Herman Thoms isolated the pure glycosides from S. kombé and S. gratus in 1904 and has unambiguously assigned them with the names k- and g-strophanthin [1].

Based on the work of Thomas Fraser, Burroughs, Wellcome & Co in 1886 introduced a S. kombé extract called "Tincture of Strophanthus". This was sold at seven shillings per ounce. In America, E.R. Squibb and Sons was one of the first suppliers of Strophanthus preparations. Particularly popular was a chocolate coated tablet of a mixture of Digitalis and Strophanthus extracts, which was sold at 16 cents per one hundred pieces [2]. In 1889, Boehringer Mannheim introduced pure k-strophanthin to the market. In cooperation with Albert Fraenkel Boehringer in 1907 introduced a solution of k-strophanthin for intravenous administration under the brand name “Kombetin”.

In 1904 E. Merck, Darmstadt, commercialized a standardized solution of pure g-strophanthin as "g-Strophanthin crystallisatum after Thoms". In 1906, also Kali-Chemie began marketing a g-strophanthin solution under the trade name “Purostrophan”. In the following years, several suppliers offered Strophanthus glycosides preparations for oral and intravenous use. In contrast to Blaustein's assertion orally administered ouabain products over the decades of their use have been given as standard medication to millions of patients. The database of the German Institute for Medical Documentation and Information records more than 20 orally administered ouabain preparations that were used in Germany after 1950. Decades of clinical experience with dozens of ouabain based preparations (i.e. treatment of millions of patients) can not be disqualified as „anecdotal“.

Blaustein's core hypothesis is that “ouabain is a key factor in the pathogenesis of hypertension and heart failure". At the same time he states that ouabain is “equipotent to digoxin” and has been used “for acute iv administration in heart failure emergencies“. By applying common sense, it can be ruled out that a substance that has been used successfully for decades as an emergency drug in the treatment of heart failure will cause heart failure. Equally excluded is that ouabain, which in clinical practice lowers blood pressure, produces hypertension. Already Fraser had pointed out that “strophanthin increases the action of the heart without raising blood pressure.” Blaustein does not discuss these obvious contradictions nor does he suggest an explanation. He as well neglects current reports on cardio protection induced by ouabain as well as conclusions by Lijune Liu and co-workers that ouabain can be beneficial to various stages of heart failure.

Based on all available data it can be ascertained that the mutually exclusive effects of plant derived ouabain and the inhibitor of the Na/K-ATPase observed in mammalian tissues do not support the hypothesis that this inhibitor is identical with ouabain, but favor the interpretation that “endogenous ouabain” is something different. Hence, Blaustein's request to establish "solid information about the normal plasma EO level under a variety of conditions" is unfounded. There is no endogenous ouabain.

African healers have long recognized the medical value of Strophanthus extracts. The medical application relied on alcoholic decotions made by steeping roots in a fermented, alcoholic beverage. The resulting bitter tasting solution would be taken in small sips over a period of days or weeks [2]. The healers knew that the effect of Strophanthus as a potent plant with both healing and highly toxic capabilities, crucially depends on the method of preparation of the drug. In 1971 this observation found a decisive scientific confirmation. Lindenbaum et al published findings that different batches of digoxin from the same manufacturer resulted in different serum concentrations [3]. This publication and subsequent studies lead to the transformation of the art of galenics from a trial-and-error exercise into a scientific discipline. Contrary to Blaustein's assertion, today we know from progress in pharmacology and galenics that absolute bioavailability is not decisive for the therapeutic effect. The only decisive factor is the serum concentration, which enables a sustained therapeutic effect. This is achieved by a correspondingly optimized galenic formulation of the active substance. Different formulations require different dosages to produce the same serum concentration. This is the explanation for the different concentrations of ouabain preparations cited by Blaustein. Contrary to Blaustein's assertion the therapeutic serum concentrations of ouabain are well known: 0.5 ng/ml in steady-state after iv administration and 0.4-0.9 ng/ml on oral administration of suitable galenic preparations.

Blaustein argues on the basis of outdated knowledge that does not take into account the effects of galenics. Today drugs such as Aliskiren, whose absorption rate is about 3%, will not be rejected just because the absorption rate is too low. Aliskiren’s therapeutic effects derive from sufficiently high serum concentrations, not from the total amount absorbed. The same is true for drugs like Nisoldipine (5%), Dabigatranetextilat (6.5%), or Ramipril (15%), which have absorption rates comparable to that of ouabain. For ouabain, absorption rates of up to 10% have been measured.

Blaustein falsely assumes that Ouabain has been withdrawn from the market because there has been a death following intravenous administration. The anecdotal evidence he refers to is a patient with multiple co-morbidities. It is outright medical malpractice to inject 0.75 mg ouabain in such a patient when the standard dose should not exceed 0.25 mg.

Ouabain preparations are no longer available because no company was willing to fund the required clinical trials. The historical preference of Digitalis glycosides over Strophanthus glycosides is due to two factors. 1. Digitalis glycosides can be produced at low cost on an industrial scale from commercial Digitalis plantations. The production of Strophanthus glycosides is and was restricted to collection of wild plants and is correspondingly expensive. 2. Cardiac glycosides were used with the aim of strengthening the contraction force of the heart muscle. Since digitalis glycosides have a stronger inotropic effect than Strophanthus glycosides, the former were preferred. Additionally, false ideas about the importance of galenics have certainly contributed to the uncertainty of clinicians.

For the locals in Africa, Strophanthus was poison and remedy in one. In the mythology of the tribe of the Wilé in Upper Volta, this plant was sent from paradise to the earth to heal or punish people according to their merit [4]. Hence, it is an ethical obligation when studying Strophanthus glycosides to apply generally accepted principles in science. Otherwise hubris and personal vanity will hinder finding the truth. Mordecai P. Blaustein breaks with this generally accepted principles in science. He ignores ideas and data that don’t fit his preconceptions and neglects conflicting results that don’t support his hypotheses. Blaustein’s narrative about the construction of an "endogenous ouabain-Na+ pump endocrine system" lacks a necessary critical perspective. It is guided by wishful thinking and not by facts.

References

[1] https://link.springer.com/chapter/10.1007/978-3-662-40381-5_7

[2] Osseo-Asare AD, Bitter roots: the search for healing plants in Africa, The University of Chicago Press, 2014

[3] Lindenbaum J, 1971

[4] Leuenberger H, Gesund durch Gift, Deutsche Verlagsanstalt Stuttgart, 1972

On 2018 Jan 12, Mordecai P Blaustein commented:

None

On 2018 Jan 12, Mordecai P Blaustein commented:

Response to Dr. Fürstenwerth

I thank Dr. Fürstenwerth for his comments about my article. His exuberant advocacy for the clinical use of ouabain is refreshingly entertaining. As he states, however, his views are based largely on “applying common sense”; he appears to ignore the experimental method and actual data. (“Common sense” also led to such ideas as, “the earth is flat,” and “the sun revolves around the earth” – notions that landed in the trash bin of history.)

1. Fürstenwerth correctly asserts that k-strophanthin is the predominant cardenolide extracted from Strophanthus kombé, but this plant produces a mixture of related steroids [1].

2. He states that the “endogenous ouabain-Na+ pump endocrine system… is… wishful thinking.” Data from multiple laboratories, summarized in my article, demonstrate that an inactivating mutation of the mouse alpha-2 Na+ pump ouabain binding site, or infusion of anti-ouabain antibodies to immuno-neutralize endogenous ouabain (EO) in rats, induces a clear phenotype. This loss of EO-Na+ pump interaction is manifested by specific disturbances of (e.g.) behavior and learning, exercise endurance, fetal development and basal blood pressure. In my view, these data trump Fürstenwerth’s “common sense”.

3. He claims that “There is no endogenous ouabain.” Has he read (or understood) the articles listed in Table 2A? Rather than relying on “common sense”, I prefer the mass spectra and NMR spectra published by such distinguished chemists/biochemists as Prof. Wilhelm Schoner [2], Prof. Tadashi Inagami [3], and Prof. Koji Nakanishi [4], a member of the National Academy of Sciences USA and one of the world’s leading natural product chemists. Moreover, the very detailed original mass spectroscopy report included all the original, rigorous purification data [5-7]. In contrast, the few investigators who were unable to detect EO (Table 2C) cut methodological corners (see text and [8]) and even “edited” their raw data [9,10] (and see [8]).

4. Fürstenwerth claims that my review “neglects” the “beneficial” effects of ouabain and “does not discuss (the)... obvious contradictions” that “ouabain lowers blood pressure, (but also) produces hypertension”. His statement is not true. Table 3 shows that mutation (inactivation) of the alpha-2 Na+ pump ouabain binding site elevates basal blood pressure; this implies that EO is normally needed to help keep blood pressure low (i.e., ‘normal’). On the other hand, Yuan et al. [11] were just the first of numerous investigators to show that prolonged, high ouabain levels elevate blood pressure. Like all hormones, ouabain can be expected to have both beneficial and, if greatly elevated for a prolonged period, detrimental effects (see Fig. 4 and pages C14 and C16 of my article).

5. I do not dispute Fürstenwerth’s assertion that the “decisive factor is the (ouabain) serum concentration”. But, in that case, given the aforementioned data, his opposition to my call for “solid information” about plasma EO/ouabain levels before and during ouabain therapy makes no sense. Drug treatment based simply on “common sense” must give way to effective therapeutic dosing that utilizes all the available scientific information to optimize treatment and patient safety.

6. Finally, Fürstenwerth states that “production of Strophanthus glycosides is… restricted to collection of wild plants.” This is not true. The complete chemical synthesis of ouabain was achieved by Deslongchamps [12] and a more concise method has now been developed [13].

In conclusion, as Withering wrote in 1785 [14], “After all, in spite of opinion, prejudice or error, Time will fix the real value upon this discovery, and determine whether I have imposed upon myself and others, or contributed to the benefit of science and mankind”.

References:

[1] Jacobs & Hoffman, J Biol Chem 69: 153-163, 1926.

[2] Schneider R, 1998

[3] Tamura M, 1994

[4] Kawamura A, 1999

[5] Hamlyn JM, 1991

[6] Ludens JH, 1991

[7] Mathews WR, 1991

[8] Hamlyn JM, 2016

[9] Baecher S, 2014

[10] Vogeser M, 2015

[11] Yuan CM, 1993

[12] Reddy MS, 2009

[13] Renata H, 2015

[14] Withering, “An Account of the Foxglove and Some of its Medical Uses”, M. Swinney for G.G.J. and J. Robinson, Birmingham, 1785.

On 2018 Jan 12, Hauke Fürstenwerth commented:

Final response to Dr. Blaustein

<p>@ 1: yes, S. kombé contains a mixture of steroids, but contrary to Blaustein’s assertion no ouabain. Kirk discovered the effects of k-strophanthin.</p>

<p>@ 2: yes, inactivating mutation of the mouse alpha-2 Na+ pump ouabain binding site has physiologic consequences. This is no evidence that the endogenous inhibitor of the NaK-pump is ouabain.</p>

<p>@ 3: unfounded accusation of data manipulation (”edited their raw data”, “scientific misconduct”) does not refute the fact that in various laboratories it has not been possible to detect ouabain in human serum with highly specific analytical methods.</p>

<p>@ 4: With the admission that ”ouabain can be expected to have both beneficial and … detrimental effects” Blaustein refutes assertions he has made in his article: “ouabain is a key factor in the pathogenesis of hypertension and heart failure" and “ouabain and its receptor site participate in the pathogenesis of hypertension, cardiac hypertrophy and HF“. Provided ouabain is the endogenous inhibitor of the NaK-pump that at low levels has positive but at elevated levels has detrimental effects, then it remains puzzling why infusion of plant derived ouabain (elevating serum concentration!) in clinical practice lowers blood pressure and is life-saving in acute heart failure. (Oh yes, common sense can be annoying.)</p>

<p>@ 5: With highly specific analytical methods it is not possible to detect “endogenous ouabain”. (Blaustein admits that there is no ”convenient EO assay.”) However, concentrations of plant derived ouabain can be measured even in extreme low concentrations. From such measurements the therapeutic levels of ouabain serum concentrations are known and have been validated by decades of clinical experience. Thus, effective therapeutic dosing of ouabain is a well established procedure.</p>

<p>@ 6: The sophisticated total syntheses of ouabain are high-lights in synthetic chemistry. These masterpieces allow the preparation of a few mg on laboratory scale, but they are not suited for large scale production of ouabain.</p>

Finally, I do agree with Blaustein that in science many notions have landed in the trash bin of history. I dare to predict that ”endogenous ouabain” , too, will suffer that fate.

On 2018 Jan 13, Mordecai P Blaustein commented:

Response to Dr. Füerstenwerth:

The case for a ouabain-Na pump endocrine system has been laid out in [1] and my previous response to Dr. Fürstenwerth. All the original reports are cited so that readers can verify my statements.

I must, however, refute Fürstenwerth’s false claim that I made an “unfounded accusation of data manipulation” by stating that Baecher et al. [2] “’edited’ their raw data”. Fürstenwerth apparently has not read Vogeser and Baecher’s Letter to the Editor [3] in which they admit that “In… Fig. 2 of our article ([2])… at a retention time (RT)… of… 5.0 min… the trace signal is broken… This inconsistency was introduced by editing the… (mass spectrum) raw data.” They show (Fig. 2, top, in [3]) that they originally (Fig. 2, top, in [2]) edited out an ion current peak at 4.99 min, and they present a second example (Fig. 1, top, in [3]) in which a similar peak is seen at that same RT (4.98 min) (see [4] Data Supplement). They do not mention the other 28 plasma samples they tested [2]; how many of them exhibited the same peak? Why didn’t they show/describe all their data? (The “broken” trace signal in Fig. 2 of [2] is very difficult to see on the original journal page. Dr. Hamlyn suspected that the spectrum was 'unusually flat'. When he enlarged the image he discovered the discontinuity.) We suggest [4] that the ion current peak at the 5.0 min RT, which has the same mass/charge ratio as ouabain, may correspond to the more polar of two ouabain isomers that have previously been described [5, 6]. Other flaws in the Baecher et al. study [2] are discussed elsewhere [1, 4, 7].

References:

[1] Blaustein MP, 2018

[2] Baecher S, 2014

[3] Vogeser M, 2015

[4] Hamlyn JM, 2016

[5] Jacobs BE, 2012

[6] Hamlyn JM, 2014

[7] Blaustein MP, 2015