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Redefining hyponatremia could be necessary for successful COVID-19 prevention and treatment

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Abstract

Would serum sodium levels below 141 mmol/L looked at and treated as hyponatremia, maybe called "COVID-19-specific hyponatremia", it could significantly improve survival rates. A similar effect is hypothesized for intensive salt inhalation. To date, the suggested inhalation methods have been voluntarily tested by 26 COVID-19 positive patients (some combining it with higher salt intake). No serious problems breathing was experienced. Hospital treatment was not necessary except 1 immunodeficient person, who needed hospitalization because of prolonged fever and pneumonia, but recovered without oxygenisation. One 90+ patient already with pneumonia at the start of using the "simple" method also recovered without hospitalization.
Redefining hyponatremia could be
necessary for successful COVID-19
prevention and treatment
Tamás Kókai, tkokai@premiere.hu
ABSTRACT
Inhaled NaCl (common salt) may help in preventing SARS-Cov-2 coronavirus infection (COVID-19) and
relieving respiratory symptoms:
In vivo, NaCl has shown an antiviral effect in the airways.
In vivo, elevated extracellular NaCl concentration has been shown to reduce cellular ACE2
expression by up to 60 percent. ACE2 is considered to be the binding site for SARS-CoV2.
Elevated extracellular NaCl has been shown in vitro to block intracellular viral replication by nearly
100 percent
Inhaled NaCl has been shown to help mucociliary clearance.
There is a strong correlation between the negative deviation of serum Na
+
levels from the median at
patient admission, especially 141 mmol / L and below and the later severity of the disease.
The current study hypothesizes that inhaled NaCl reduces ACE-2 expression in airway epithelial cells,
reducing virus binding, and blocks viral replication within infected cells. Improved mucociliary clearance helps
in preventing infection and a milder course of the disease in the lungs. A clinical trial is considered
necessary.
A related hypothesis of the current study is that salt deficiency, and therefore low sNa
+
(and ultimately, low
intercellular Na
+
) due to heavy sweating may explain why people doing exhausting high-profile sports are
infected by the virus at an unexpectedly high proportion. Low sNa
+
may also play a key role in obese people
because of a combination of factors, including sweating and elevated urine Na
+
excretion. The high
prevalence of fatalities among patients with hypertension may also be explained by a low-salt diet and the
use of (thiazide) diuretics.
The current study also hypothesizes that serum Na-levels - because of the ACE2-expression downregulating
role of NaCl/Na
+
- should be regarded as a key factor in the prevention and treatment of COVID-19 and that
the elevated ACE2-expression caused by lower than average sNa
+
explains most COVID-19 phenomena
experienced. Consequently, it would be essential to look at sNa
+
levels of 141 mmol / L and below as
hyponatremia, at least as a work hypothesis for further investigation, and to consider sNa
+
levels of 142-145
mmol / L as ideal in terms of coronavirus prevention and treatment.
Pre-COVID-19 normals may have to be overridden by new normals for a successful COVID-19
management, especially in the light that the virus is most probably of zoonotic - bat - origin where the virus is
essentially non-lethal, and healthy bat sNa
+
- levels are 146 ± 5 mmol / L, just outside of the range in patients
with elevated danger of serious or lethal complications.
INTRODUCTION
COVID-19 has become a pandemic since its first outbreak in Wuhan, China in 2019. This writing was started
in March, 2020, concentrating on the potential applicability of inhaled NaCl in the prevention and treatment of
a SARS-CoV-2 infection. During the course of writing, so many pieces of the puzzle pointing to a (relative)
salt deficiency have emerged, that it was extended to cover the role of Na(Cl) related to COVID-19 in
general, in order to provide a consistent explanation.
INTEREST
The author refers to experience with LibAirator, a salt therapy device invented and developed by himself. It
generates dry salt nanoparticles, which can arguably be the most suitable solution for the purpose of
COVID-19 prevention and alleviation of symptoms in the airways, provided the present hypothesis is valid.
However, the author also suggests an alternative device (LibAirNose) which is simple, easy to make in a
home-made version, and easily applicable anywhere. It is arguably more efficient than known solutions
based on wet aerosolization and safer as far as potential virus transmission is concerned, and can be used
in a clinical setting.
The author also declares that his thoughts on the necessity of maintaining higher serum Na
+
-levels and the
eventual suspension of a low-salt diet do not serve any business interest.
APPLIED DEVICE AND METHOD
LibAirator is a device that has been used successfully to prevent and alleviate respiratory symptoms by
inhalation of dry salt nanoparticles (of about 1 nm size) released into the immediate environment of the user.
LibAirator is a Class I medical device (OGYÉI HU / CA01 / 12001/2018), a European patent (EP3240530),
patent pending in the United States, and has been on the market since 2018 with nearly 10,000 users. The
device is not based on conventional wet aerosol generation, therefore, there is no risk of virus transmission
by the emitted particles. It only requires natural inhalation and exhalation; it moves less air than human
respiration (315 liters / hour), so any concerns about the device extensively moving air in a clinical
environment are unfounded. The inlet side of the device can be hermetically sealed with a HEPA filter to
prevent internal contamination. Its effect depends on the user’s distance from the device. In everyday use,
the device is placed within arm's reach, with a typical duration of 8 hours per day. In addition, intensive use
(“shock therapy”) from close for up to 30 minutes is recommended, as needed. Based on the results of study
cited in point 2 below which describes how NaCl reduces / blocks intracellular replication of SARS-Cov2
virus, this shock therapy may be particularly effective.
SUGGESTED ALTERNATIVE DEVICE AND METHOD USABLE WIDELY AND IMMEDIATELY
The device is a small container held or fixed with a strap under the nose containing salt grains wrapped in a
thin absorbent material. It is to be moistened with a few drops of water before the first use, so that it acts as a
single salty block afterward. The salt(bag) is cyclically wetted by exhalation and desorbed by inhalation,
resulting in the inhaled air being enriched with salt. The dose is comparable to that of a bather sitting up to
their neck in the Dead Sea, therefore, it can be considered safe. The device is patent pending and is
expected to be marketed as LibAirNose, but the idea can be freely used for non-commercial purposes with
non-industrial manufacturing methods (a homemade version can be a beverage cap deformed oval).
Suggested application: 3x60 or 6x15 minutes per day; additional maintenance application depending on the
effect experienced. (The taste of sputum should taste at least as salty as a 1.5% NaCl solution).
RESEARCH RESULTS TO DATE
1. NaCl has an antiviral effect in the airways, as confirmed and theoretically substantiated by ELVIS
(Edinburgh & Lothians Viral Intervention Study ([1] Ramalingam et al., Sci Rep 9, 1015 (2019)) : [2]
Ramalingam et al., Sci Rep 8, 13630 (2018). In this clinical trial, although only regular saline gargling
and saline nasal rinsing were applied, significant improvement in viral upper respiratory tract
infection (URTI) indicators could be achieved compared to the control group: 1.9 days sooner
recovery, 36% lower OTC drug use. It was further experienced that people living in the same
household were 35 % less likely to get infected, meaning the antiviral effect works both ways. in
2020, a re-analysis of the data collected in the study revealed that those infected with coronaviruses
causing common cold recovered 2.5 days sooner (5.6 days instead of 8.1 days), based on which the
authors considered it necessary to repeat the trial as soon as possible, focusing on COVID-19: [3]
Ramalingam et al., J Glob Health. 2020, which has started.
As the dry salt nanoparticles emitted by LibAirator reach the airways and sinuses entirely , it can be
assumed that the device can be used to achieve even better results than those found in the ELVIS
study. Our questionnaire survey on infectious respiratory diseases (see later) is consistent with the
hypothesis. A further supporting evidence which can be considered objective, is that according to
user feedback on LibAirator use, among preschoolers, the number of days spent at home with
respiratory illnesses is typically reduced by half or to a third.
2. The study by [4] Rafael et al., BioRxiv, 2020 shows in detail how NaCl reduces intracellular
replication of the SARS-Cov2 virus in vitro in Vero cells, depending on extracellular salt
concentration. Above the concentration of 0.8%, intracellular viral replication is significantly reduced,
and at 1.5%, it is practically blocked. This concentration can presumably be achieved on the surface
of the airways using inhaled NaCl. Based on the article, regular shock therapy appears to be the
most suitable for blocking viral replication, given that a high-concentration shock causes
depolarization in airway epithelial cells for a day, presumably in close association with viral
replication blocking. The authors suggest that inhaled NaCl may be suitable for both prophylaxis and
therapy, and therefore a clinical trial is considered necessary.
3. Inhaled NaCl may be suitable for reducing ACE2 expression in airway epithelial cells, reducing the
possibility and pace of an infection. The expression of ACE2, which is considered to be the binding
site for SARS-CoV-2, can be reduced by NaCl, which has been demonstrated in kidney in vivo: [5]
Guy et al., Biochemistry 2003, [6] Elased et al., Hypertension, 2006, [7] Bernardi et al., Nephrology
Dialysis Transplantation, 2012. In the latter study, a diet containing 1.2% salt reduced ACE2 gene
expression in the glomeruli of the experimental animals by 60%. The discussion of the study [4]
Rafael et al., BioRxiv, 2020 cited above analyzes in detail the relevant similarities between kidneys
and the lungs, suggesting that the effect is similar in airway epithelial cells.
4. A very strong negative correlation can be observed between serum Na
+
levels measured at
admission and the later severity of the disease, as demonstrated by [8] Yi Luo et al., MedRxiv, 2020,
analyzing data of thousands of Chinese and more than 2,000 American patients. Of all ions, only Na
+
showed a prominent (negative) correlation. The correlation is particularly striking if we examine not
the averaged data of a region but the data of a particular institution where the laboratory tests have
been likely made under the same conditions.
A typical data set:
- average serum sodium level at time of admission of patients with the most severe progress is 137
mmol / l or below
- average level of patients with moderately serious progress is 138.7 mmol / L
- average level of patients with mild progress is 140.8 mmol / L
- while the healthy average is 142 mmol / L and that of asymptomatic bats is 146 mmol / L.
It may be assumed that low Na
+
level is a consequence of the disease, but according to the authors
this is unlikely and they find it much more associated with a low-salt diet or age. The close
association with disease severity is attributed to the effect of salt (deficiency) on ACE-2 expression.
According to the authors, the revealed interrelation may serve as a basis for the development of new
COVID-19 prevention and therapeutic procedures.
In their opinion piece [9] Post et al., EJIM, 2020 suggest increasing salt intake at the onset of
symptoms and pausing a low-salt diet for the duration of the COVID-19 epidemic. In September, in
the possession of more data, many of them referred to in this writing, suggest that sodium intake and
status should be monitored carefully during severe COVID-19 infections and low sodium intake be
treated early in its course, despite a potential conflict regarding common dietary recommendations:
[10] Post et al. ., VirusRes, 2020.
Several other publications also deal with the correlation between electrolyte levels in severe vs.
non-severe coronavirus patients, but only in relation to the systematic discrepancy experienced, and
only with the conclusion that it is worth paying attention to electrolyte levels, such as [11] Lippi et al.,
Ann. Clin. Biochem., 2020. This study, summarizing data from 36 studies and tested for bias,
obtained a WMD of -0.91 mmol / L [95% CI: –1.33 to –0.50 mmol / L] by comparing severe vs.
non-severe cases. Analyzing the data, it is apparent that above the median value of 142 mmol / L,
hardly any patients became seriously ill. For other electrolytes, no such strong correlation can be
found.
Low Na
+
levels may also explain why people in top-class strenuous sports, especially athletes can
get unexpectedly easily infected. It is well known that heavy sweating due to strenuous exercising for
several hours can cause a serious drop in serum Na
+
level. The phenomenon even has a name:
Exercise Associated Hyponatremia (EAH) [12]. Overweight people tend to have elevated urine Na
+
excretion and also sweat excessively, which may partly explain their high vulnerability on top of the
extra risk posed by the high ACE2-expression level of the adipose tissue. The high prevalence of
fatalities among patients with hypertension may also be explained by keeping a recommended
low-salt diet and possibly the use of (thiazide) diuretics.
Pieces of information in 1-4. on COVID-19 seem to fit together:
- ACE2 is considered to be the binding site for SARS-CoV2
- Organs with high ACE2 expression ([13] Lei et al., Infect Dis Poverty 9, 45 ,2020) seem to be the
most affected.
- High NaCl salt intake is known to downregulate ACE2, but the exact relationship is not known
- However, there is convincing evidence that 141 (or 142, for that matter) mmol / L serum Na
+
is a
critical level in this respect, no matter the underlying reason.
- Therefore, it can be concluded that “sufficient” dowregulation of ACE2 takes place above 141 mmol
/ L, and that by maintaining serum Na
+
levels above 141 mmol / L, serious complications related to
COVID-19 could likely be avoided.
It can be assumed that by a reasonable increase of salt intake or other measures (e.g. giving up a
low salt diet, replacing - suspected - thiazide diuretics with other substances, stopping
overconsumption of water, etc.), and thus an increase in serum Na
+
to at least 142 mmol / L, which
corresponds to the healthy average, a significant potential risk factor could be eliminated. The risk is
negligible on the population scale: statistically, the cost of health care for patients with too low serum
Na
+
levels is much higher than for those with too high serum Na
+
levels ([14] Shea et al., J Am Soc
Nephrol. 2008, Corona et al., AJM, 2016).
5. Mucociliary clearance is the number one antiviral defense mechanism of the airways ([15] Li et al.,
FEBS J., 2020). If self-cleansing is inadequate, the infection can get easier deep in the airways. In
the worst case, the infection destroys the cilia of the ciliated epithelium responsible for mucociliary
clearance ([14] Li et al., FEBS J., 2020) and surfactant production of type 2 pneumocytes ([16]
Mason, AJP-Lung, 2020), therefore, it may be particularly important to aid in the removal of
secretion, especially the hyaluronic acid based hydrogel accumulating in the alveolar region [17]
Garvin et al., eLIfe, 2020, [18] Hellman et al., J. of Biochem., 2020
Efficient support of mucociliary clearance can be a key factor behind the positive experiences with
LibAirator in the treatment of other respiratory diseases. During the development of LibAirator, it was
concluded* that the NaCl particles produced by LibAirator partly act as an exogenous surfactant,
more precisely, as "patcher" of the existing surfactant layer. This may be explained by the fact that
one Na
+
ion binds to the carbonyl oxygen of an average of 3 lipids with a strong bond, leading to
larger complexes ([19] Böckmann et al., Biophys. J., 2003). In addition to improving mucociliary
clearance, this "surfactant-patching" effect may play a key role in preventing alveolar surfactant
deficiency in severe (ARDS) cases.
QUESTIONNAIRE RESULTS
To put the idea of potential suitability of the LibAirator to the test, in March 2020, we asked users to complete
a targeted online questionnaire on respiratory infections in order to find out how the incidence and course of
infectious respiratory diseases had changed by using LibAirator. A brief summary of the first 108 responses
that have been processed:
Changes in general but relevant respiratory problems:
Secretion clearance: 28.7% “It has become much easier”, 36.1% “It has become easier”, even with
limited compliance. The proportion of a positive change can be approx. 80% because unfortunately
there was no “I’m not involved” answer. (The effect can be significantly increased in a short time with
intensive use.)
Dry cough: 10.7% “Completely gone”, 34.7% “Became much rarer”, 29.3% “Became rarer”. The
share of positive change is 74.7%.
Respiratory allergy symptoms: 4.8% “They are completely gone”, 39.7% “They have become much
rarer”, 25.4% “They have become rarer”. The proportion of a positive change is 69.9%. A similar
positive change in the duration and severity of symptoms has been reported.
Changes in viral respiratory infections:
Common cold symptoms: 5.3% “Completely gone”, 29.8% “Much rarer”, 37.2% “Rarer”. The
proportion of a positive change is 72.3%. A similar positive change in the duration and severity of
symptoms has been reported.
Influenza symptoms: 33.3% “They have not been since”, 13.7% “They have become much rarer”,
17.6% “They have become rarer”. The proportion of a positive change is 64.6%. A positive change in
the duration and severity of symptoms has also been reported.
Since the device has been on the market only since 2018 and the flu is not an everyday disease,
there is more uncertainty, it is more difficult to compare with previous periods.
Croup: It does not affect the most vulnerable age groups in terms of coronavirus, but since it is of
viral origin, we asked about it under 14 years of age. The sample is small, but in most cases the
symptoms were completely gone or have become less frequent. A similar positive change in the
duration and severity of symptoms has been reported.
COVID-19: There was no one diagnosed with coronavirus among the respondents (March 2020).
Those who chose “Maybe” or “I don’t know” as an answer, reported “More severe” or “I don’t know”,
but not “Much more severe” conditions compared to an average flu. Feedback from confirmed
coronavirus patients came as a message from the United States stating that, despite severe other
symptoms, no severe respiratory symptoms were experienced. The devices were only used after the
diagnosis.
Detailed questionnaire results are available here: [20]
LibAirator_Infectious_Airway_Diseases_Questionnaire_March_2020_Results.pdf
CONCLUSION
Inhalation of NaCl may provide a combined effect that can prevent or significantly reduce the severity of
respiratory disease caused by SARS-CoV-2.
It has an antiviral effect, reducing the possibility and pace of infection (see 1. and 2.)
It has an ACE2 expression downregulating effect, reducing the possibility and pace of infection (see
2. and 3.)
As a result of the above two effects, it helps to prevent a decrease in surfactant production (see 5.)
By improving mucociliary clearance, it slows down the pace of infection spreading through the
airways, leaving time for the build-up defense (see 5 .)
It helps in the removal of hyaluronic acid-based hydrogels that are difficult to release from the
alveolar region, which can be critical. (see 5.)
It helps to prevent surfactant deficiency in the alveolar region by "patching" the existing surfactant
layer. (see 5.)
A related hypothesis is that the risks of COVID-19 to other organs, especially the kidney, can be greatly
reduced by setting the recommended serum Na
+
level at 142-145 mmol / L at least for the duration of the
COVID-19 epidemic, with consideration of individual risks and appropriate control. (see 4.)
Also knowing that the virus is most probably of zoonotic - bat - origin where the virus is essentially non-lethal,
and healthy bat serum Na
+
- levels are 146 ± 5 mmol / L, just outside of the range in patients with elevated
risk of serious or lethal complications, it is hypothesized that serum Na
+
- levels considered healthy and the
definition of hyponatremia set in pre-COVID-19 times are invalid, and an immediate revision is to be
considered for a successful COVID-19 management.
EXPECTED RESULTS
Based on the research results and our questionnaire survey on respiratory infections, the presumed effect of
prophylactic use of inhaled NaCl against COVID-19 is 50 to 60 percent less frequent and significantly milder
respiratory symptoms. If treatment is started only after diagnosis but as soon as possible, the presumed
effect is a significantly milder course of respiratory symptoms, a less than 50 percent reduction in surfactant
production due to the infection, effective removal of the hydrogel from the alveolar region, and thus the
avoidance of mechanical ventilation.
The effect expected from increased dietary sodium intake or other measures (e.g. giving up a low salt diet,
replacing - suspected - thiazide diuretics with other substances, stopping overconsumption of water, etc.),
and thus an increase in serum Na
+
to at least 142 mmol / L, a much milder course can be expected in other
affected organs, especially the kidneys.
SUGGESTED TEST PROTOCOLS
The effect of inhaled (dry) NaCl must be tested under conditions that allow a clear assessment of its
suitability for the purpose. It must be noted that the LibAirator was designed to be placed within arm's length
from the patient, it emits only dry salt particles, moves air only as much as (approximately) human breathing
does, therefore, there is no conceivable risk for the device to foster the spread of viruses within an institution,
and the internal contamination of the device can be prevented by placing a HEPA pre-filter on the backplate.
The sterilization procedure to which the device can be subjected is being examined. Gamma, UV and ozone
sterilization appear to be trouble-free; it is also possible to blow the inside of the device with 96% alcohol
after removing the removable front plate. The simple device proposed as an alternative is disposable or can
be disinfected by any sterilization procedure.
In a study suitable for testing the alleviation of the course of the disease, it would be advisable to use the
devices as part of home / hospital therapy in patients newly diagnosed with COVID-19, and to compare their
experience and course with those who do not use the devices. The test protocol is an adapted version of the
aforementioned [21] Hypertonic Saline Nasal Irrigation and Gargling in Suspected or Confirmed COVID-19
(ELVIS COVID-19), which is largely based on the validated Wisconsin Upper Respiratory Symptom
Survey-24 (WURSS-24 ) questionnaire and patient diary, and a record of other indicators.
As an indicator of a reduction in the risk of infection, changes in airway ACE2 levels can also be examined in
healthy individuals based on airway samples if we accept that a decrease in ACE2 levels is closely
correlated (negatively) with the risk of disease. Endobronchial biopsy is required for execution ([22] Wark et
al, medRxiv, 2020), but nasal mucosa sampling may be sufficient for a first estimate. A small sample size (10
people) would be sufficient, no control group is required. Selection criteria: no inhaled NaCl use, serum Na
+
under141, COVID-19 infection negativity. Exclusion criteria: Inhaled or systemic corticosteroid use. Protocol:
2 samples prior to treatment followed by daily samples for 5 consecutive days. LibAirator use: normal use +
3x15 minutes per day shock therapy application; possibly 5 people 3x15 minutes, 5 people 3x30 minutes.
Use of the device attached under the nose: 6x30 or 3x60 minutes per day.
RESEARCH IDEA
A simple - although not conclusive - test of the concept would be to observe if asymptomatic, COVID-19
infected bats would show serious symptoms experienced in humans if they are kept on a low-salt diet so that
their serum Na
+
decreases to 135 mmol / L, which is the lower end of the range labelled as healthy in
humans.
DISCUSSION
If the presumed effect is confirmed, the suggested NaCl inhalation methods can be used for therapeutic
purposes in both clinical and non-clinical settings, and for preventive purposes especially in places where the
risk of respiratory infection is always present, such as hospitals and nursing homes.
According to the author’s experience, there seems to be a mental block in the way of thinking beyond
protocols and healthy levels set under pre-COVID-19 circumstances. A critical revision may help in fulfilling
the immediate need for more efficient COVID-19 treatment practices.
With the emergence of more and more viruses of zoonotic origin, it may be worth further consideration if the
change in our chemical composition due to dietary and medication practices of the past decades is a factor
that makes us more vulnerable to the new viral challenges of the present.
* Logical steps:
The effect of improved secretion clearance is known (see questionnaire, effective in cystic fibrosis,
etc.)
It is known that the amount of inhaled NaCl is on a scale of micrograms per hour (the emission of the
LibAirator device measured by absorption followed by laboratory Na
+
measurement is approx. 10
micrograms / hour)
The question is how a few micrograms can be sufficient on a surface as big as a tennis court
most probably acts in a very thin layer
It is known that surfactants are only present in a layer of molecular thickness and improve clearance
What amount of NaCl is sufficient to cover the surface of airways as big as a tennis court with a
saturated (36%) saline solution (as an extreme) in a nanometer-thick layer? - only 2 micrograms
Can NaCl influence the behaviour of surfactants? - yes
Is there a more precise explanation? Yes: An Na
+
ion binds to the carbonyl oxygen of an average of
3 lipids with a strong bond, creating larger contiguous lipid groups ([19] Böckmann et al., Biophys. J.,
2003). Within the lipid-protein ratio range of ¼ to 4/1, the respiratory surfactant represents 4/1 of the
lipid-protein complexes in favour of lipids, therefore NaCl can particularly influence its behaviour.
Conclusion: this is probably the mechanism of the mucociliary-clearance-helping effect of inhaled
NaCl
REFERENCES
[1] Ramalingam, S., Graham, C., Dove, J. et al.: A pilot, open labelled, randomised controlled trial of
hypertonic saline nasal irrigation and gargling for the common cold. Sci Rep 9, 1015 (2019).
https://doi.org/10.1038/s41598-018-37703-3
[2] Ramalingam, S., Cai, B., Wong, J. et al.: Antiviral innate immune response in non-myeloid cells is
augmented by chloride ions via an increase in intracellular hypochlorous acid levels. Sci Rep 8, 13630
(2018). https://doi.org/10.1038/s41598-018-31936-y
[3] Ramalingam S, Graham C, Dove J, Morrice L, Sheikh A.: Hypertonic saline nasal irrigation and gargling
should be considered as a treatment option for COVID-19. J Glob Health 2020;10(1):010332. doi:
https://doi.org/10.7189/jogh.10.010332
[4] Rafael R. G. Machado, Talita Glaser, Danielle B. Araujo, Lyvia Lintzmaier Petiz, Danielle B. L. Oliveira,
Giuliana S. Durigon, Alessandra L. Leal, João Renato R. Pinho, Luis Carlos S. Ferreira, Henning Ulrich,
Edison L. Durigon, Cristiane R. Guzzo: Hypertonic saline solution inhibits SARS-CoV-2 in vitro assay bioRxiv
2020.08.04.235549; doi: https://doi.org/10.1101/2020.08.04.235549
[5] Jodie L. Guy, Richard M. Jackson, K. Ravi Acharya, Edward D. Sturrock, Nigel M. Hooper, and Anthony
J. Turner Angiotensin-Converting Enzyme-2 (ACE2):Comparative Modeling of the Active Site, Specificity
Requirements, and Chloride Dependence. Biochemistry 2003 42 (45), 13185-13192
DOI: https://doi.org/10.1021/bi035268s
[6] Khalid M. Elased, Tatiana S. Cunha, Susan B. Gurley, Thomas M. Coffman, and Mariana Morris: New
Mass Spectrometric Assay for Angiotensin-Converting Enzyme 2 Activity. Hypertension 2006;47:1010–1017
https://doi.org/10.1161/01.HYP.0000215588.38536.30
[7] Stella Bernardi, Barbara Toffoli, Cristina Zennaro, Christos Tikellis, Silvia Monticone, Pasquale Losurdo,
Giuseppe Bellini, Merlin C. Thomas, Francesco Fallo, Franco Veglio, Colin I. Johnston, Bruno Fabris,
High-salt diet increases glomerular ACE/ACE2 ratio leading to oxidative stress and kidney damage,
Nephrology Dialysis Transplantation, Volume 27, Issue 5, May 2012, Pages 1793–1800,
https://doi.org/10.1093/ndt/gfr600
[8] Low blood sodium increases risk and severity of COVID-19: a systematic review, meta-analysis and
retrospective cohort study. Yi Luo, Yirong Li, Jiapei Dai medRxiv 2020.05.18.20102509; doi:
https://doi.org/10.1101/2020.05.18.20102509
[9] Adrian Post, Robin P.F. Dullaart, Stephan J.L. Bakker: Letter to the Editor, Is low sodium intake a risk
factor for severe and fatal COVID-19 infection? European Journal of Internal Medicine, 08 April 2020,
https://doi.org/10.1016/j.ejim.2020.04.003
[10] Adrian Post, Robin P.F. Dullaart, Stephan J.L. Bakker: Sodium status and kidney involvement during
COVID-19 infection, Virus Research, Volume 286, 2020, 198034, ISSN 0168-1702,
https://doi.org/10.1016/j.virusres.2020.198034
[11] Lippi G, South AM, Henry BM.: Electrolyte imbalances in patients with severe coronavirus disease 2019
(COVID-19). Annals of Clinical Biochemistry. 2020;57(3):262-265. doi:
https://doi.org/10.1177/0004563220922255
[12] Hew-Butler, T., Loi, V., Pani, A., & Rosner, M. H. (2017). Exercise-Associated Hyponatremia: 2017
Update. Frontiers in medicine, 4, 21. https://doi.org/10.3389/fmed.2017.00021
[13] Li, MY., Li, L., Zhang, Y. et al.: Expression of the SARS-CoV-2 cell receptor gene ACE2 in a wide variety
of human tissues. Infect Dis Poverty 9, 45 (2020). https://doi.org/10.1186/s40249-020-00662-x
[14] Corona G, Giuliani C, Parenti G, Colombo GL, Sforza A, Maggi M, Forti G, Peri A.: The Economic
Burden of Hyponatremia: Systematic Review and Meta-Analysis. Am J Med. 2016 Aug;129(8):823-835.e4.
Epub 2016 Apr 5. PMID: 27059386 doi: https://doi.org/10.1016/j.amjmed.2016.03.007.
[15] Li, W., Li, M. and Ou, G.:COVID19, cilia, and smell. FEBS J (2020), 287: 3672-3676.
https://doi.org/10.1111/febs.15491
[16] Robert J. Mason: Thoughts on the alveolar phase of COVID-19 American Journal of Physiology-Lung
Cellular and Molecular Physiology 2020 319:1, L115-L120 https://doi.org/10.1152/ajplung.00126.2020
[17] Michael R Garvin, Christiane Alvarez, J Izaak Miller, Erica T Prates, Angelica M Walker, B Kirtley Amos,
Alan E Mast, Amy Justice, Bruce Aronow, Daniel Jacobson A mechanistic model and therapeutic
interventions for COVID-19 involving a RAS-mediated bradykinin storm eLife 2020;9:e59177 DOI:
https://doi.org/10.7554/eLife.59177
[18] Urban Hellman, Mats G. Karlsson, Anna Engström-Laurent, Sara Cajander, Luiza Dorofte, Clas Ahlm,
Claude Laurent, and Anders Blomberg: Presence of hyaluronan in lung alveoli in severe Covid-19: An
opening for new treatment options? J. Biol. Chem. 2020 295: 15418-. doi:
https://doi.org/10.1074/jbc.AC120.015967
[19] Rainer A. Böckmann, Agnieszka Hac, Thomas Heimburg, and Helmut Grubmüller Effect of Sodium
Chloride on a Lipid Bilayer, Biophysical journal, Volume 85, Issue 3, P1647-1655, September 01, 2003
DOI:https://doi.org/10.1016/S0006-3495(03)74594-9
[20] Tamás Kókai LibAirator_Infectious_Airway_Diseases_Questionnaire_March_2020_Results.pdf March
2020
https://www.libairator.com/custom/liblib/image/data/Kerdoiv2020mar/LibAirator_Infectious_Airway_Diseases
_Questionnaire_March_2020_Results.pdf
[21] Hypertonic Saline Nasal Irrigation and Gargling in Suspected or Confirmed COVID-19 (ELVIS
COVID-19) https://clinicaltrials.gov/ct2/show/NCT04382131
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