Apple Cider Vinegar (ACV), Phloretin, Phloridzin, Chlorogenic Acid, OAT3, Autism and Colon Cancer

Today’s post is only marginally related to autism, but does again show how some common food products have potential medical benefits.

Where I currently live people have been using apple cider vinegar (ACV) as a home remedy for generations. It is the apple part, rather than the vinegar part that is most interesting. I think they should continue with this home remedy, just be careful not to dissolve the enamel on their teeth. 

Rather surprisingly we can link ACV to improving Bumetanide effectiveness in autism and the chemoprotective effect of statins.

I have read so much research about statins, I do take Atorvastatin myself. The only downside is that research shows it does increase fasting glucose levels by about 0.4 mmol/L, exactly why nobody is quite sure.

If you want to further boost the chemoprotective power of statins it seems you may need a little help from something called Phloretin. Phloretin is a phenol that occurs in apples and the leaves of apple trees.  Apple cider vinegar (ACV) is rich in Phloretin.

Synergistic inhibition of colon cancer cell growth by a combination of atorvastatin and phloretin

Viability of HCT 116 colon cancer cells 48 hours after treatment with:-

PT = Phloretin

ATST = Atorvastatin

PT+ATST =  Phloretin + Atorvastatin

The closer to zero the better the result.  

If you want to improve insulin sensitivity and reduce fasting glucose levels it looks like it is the Phloridzin, a close relative of Phloretin, in apple cider vinegar that is useful.

If you want to improve the pharmacokinetics (how a drug is absorbed, distributed, metabolized, and excreted) of bumetanide you may also be able to use apple cider vinegar (ACV).  ACV also contains Chlorogenic acid which we we saw in an earlier post inhibits excretion of bumetanide through OAT3 (Organic acid transporter 3). Chlorogenic acid is also found in coffee.

In theory ACV will cause the level of bumetanide in blood to be higher, which might increase the amount that crosses the blood brain barrier and so make bumetanide a more potent autism drug. 

One odd proposed benefit of ACV is on GERD/reflux. You might have thought taking an acid would be the last thing that would help.

You would have thought that strong alcohol (also low pH, so very acidic) would also upset people with GERD/esophagitis, but some people I know swear that it is very beneficial.

In the case of GERD/esophagitis rather bizarrely I think it is the acetic acid (low pH) that is the reason why ACV seems to help some people.  I think it may help via feedback loops to trick the body into reducing its own acid production.

The drawbacks of Apple Cider Vinegar (ACV)

The acetic acid in apple cider vinegar can damage your teeth and your esophagus.  People avoid these problems by diluting ACV in a glass of water and rinsing their mouth with clean water afterwards.

ACV can lower potassium levels and it will lower blood glucose levels, which is good thing for most people, but diabetics would need to take care. Low potassium seems to worsen behaviour and increase sound sensitivity.

The Phloridzin in ACV is likely to reduce appetite, which for most people is a good thing, but for those few who struggle to gain weight it might be an issue.

ACV should lower triglycerides significantly, which might be bad for somebody. 

Apple phytochemicals and their health benefits

Synergistic inhibition of colon cancer cell growth by a combination of atorvastatin and phloretin

The results of the present study demonstrated that the antitumor efficacy of ATST could be enhanced at a relatively low dosage through the synergistic action with PT, which suggested the potential interaction of statins with other compounds in the food matrix. This interaction affects the efficacy of statins, and may explain the controversial results obtained in prior studies regarding the associations between statin use and the risk of colon cancer-associated mortality (27,28). As the dietary composition is different for each individual, this can result in varying statin efficacy. Conversely, different statins have different antitumor effects. In six colorectal cancer cell lines, including DLD1, HT29, SW620, HCT116, LoVo and colo320, simvastatin and fluvastatin showed strong growth suppressive effects. Atorvastatin demonstrated a relatively weak growth suppressive effect, whereas no growth suppressive effect was observed with pravastatin (29). This may be another reason for the paradoxical results regarding the antitumor effects of statins.

Therefore, the p21 gene may be the potential regulatory target underlying the G₂/M phase arrest following the synergistic action of ATST and PT; more in depth future investigations are warranted.

In summary, the present study demonstrated that PT and ATST produce a powerful synergistic interaction in suppressing colon cancer cell growth. This process was accomplished via the synergistic induction of apoptosis and the arrest of the cell cycle at the G₂/M checkpoint, which resulted from downregulated cdc2 activation following combined treatment.

Polyphenols: food sources and bioavailability

Screening of bioactive components in grape and apple vinegars: Antioxidant and antimicrobial potential

Vinegars contain several bioactive compounds that are characterized according to the type of the raw material, such as grape vinegars and apple vinegars. Liquid chromatography coupled to diode array detection and electrospray ionization tandem mass spectrometry was used for identification and quantification of phenolic compounds. Antioxidant properties of vinegars were determined by 2,2‐diphenyl‐1‐picrylhydrazyl and 2,2′‐azino‐bis‐3‐ethylbenzthiazoline‐6‐sulphonic acid assays. Antimicrobial activities of vinegars were examined with an agar disc diffusion method with Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. Gallic acid and chlorogenic acid were found to be the major phenolic acids accounting for the largest proportion of the total phenolic acid contents in grape vinegars and apple vinegars. Within the flavonols, quercetin‐3‐O‐galactoside and quercetin were detected as the major compounds in grape vinegars. Apple vinegars were characterized by phloridzin, phloretin and high chlorogenic acid content. Antimicrobial activity results indicated that grape vinegars exhibited higher antimicrobial activity against tested bacterial strains correlated with their higher antioxidant capacity.

In conclusion, gallic acid, tyrosol, protocatechuic acid, caftaric acid, catechin, epicatechin and syringic acid constituted the highest proportion of the total phenolic contents in GV. Chlorogenic acid, phloridzin and phloretin were found to be the major phenolic compounds in AV. With respect to antimicrobial and antioxidant activity results, GV showed higher antimicrobial and antioxidant activity than AV. With regard to phenolic composition of vinegars with their antioxidant capacities, two separate groups were obtained and characterized the vinegars with PCA based on the type of raw material. The results we obtained in this study extend our knowledge about the composition of vinegars obtained from different raw materials consumed in Turkey and allow the consumer to compare vinegar brands with the highest contents of beneficial compounds.

OAT3 inhibitors for Bumetanide - Probenecid, but also Aspirin, Chlorogenic acid (Coffee), Epicatechin (Cocoa, Cinnamon) and more.

Coffee = chlorogenic acids  = 1,3- and 1,5-dicaffeoylquinic acid

Interaction of Natural Dietary and Herbal Anionic Compounds and Flavonoids with Human Organic Anion Transporters 1 (SLC22A6), 3 (SLC22A8), and 4 (SLC22A11)

Five compounds, 1,3- and 1,5-dicaffeoylquinic acid, ginkgolic acids (15 : 1) and (17 : 1), and epicatechin, significantly inhibited hOAT3 transport under similar conditions

3.2. Inhibition of hOAT3 by Natural Anionic Compounds and Flavonoids

Human OAT3 expressing cells showed about 4-fold greater accumulation of ES as compared to background control cells ( versus  pmol mg 10  , resp.). Similar to hOAT1, hOAT3-mediated ES uptake was completely (>96% inhibition) blocked by probenecid (Figure 4). Five of the compounds, 1,3- and 1,5-dicaffeoylquinic acid, epicatechin, and ginkgolic acids (15 : 1) and (17 : 1), significantly inhibited hOAT3-mediated transport at 50-fold excess (Figure 4). 1,3-Dicaffeoylquinic acid and ginkgolic acid (17 : 1) exhibited 41% inhibition, while 30–35% reduction of hOAT3-mediated ES uptake was observed for 1,5-dicaffeoylquinic acid, epicatechin, and ginkgolic acid (15 : 1). Catechin, 18β-glycyrrhetinic acid, and ursolic acid failed to produce significant inhibition. Based on the level of inhibition observed, values for all of these compounds would be greater than 50 μM, much higher than clinically relevant concentrations (Table 1). Therefore, further dose-response studies were not performed.

Phloridzin reduces blood glucose levels and improves lipids metabolism in streptozotocin-induced diabetic rats.

Abstract

Phloridzin is the specific and competitive inhibition of sodium/glucose cotransporters in the intestine (SGLT1) and kidney (SGLT2). This property which could be useful in the management of postprandial hyperglycemia in diabetes and related disorders. Phloridzin is one of the dihydrochalcones typically contained in apples and in apple-derived products. The effect of phloridzin orally doses 5, 10, 20 and 40 mg/kg body weight on diabetes was tested in a streptozotocin-induced rat model of diabetes type 1. From beneficial effect of this compound is significant reduction of blood glucose levels and improve dyslipidemia in diabetic rats. As a well-known consequence of becoming diabetic, urine volume and water intake were significantly increased. Administration of phloridzin reduced urine volume and water intake in a dose-dependent manner. Phloretin decreases of food consumption, as well as a marked lowering in the weight. In conclusion, this compound could be proposed as an antihyperglycemic and antihyperlipidemic agent in diabetes and potential therapeutic in obesity.  

Harvard Medical School vs the BBC?

You might expect when it comes to investigating health claims about apple cider vinegar (ACV) that Harvard would give you the science and the BBC would be just superficial.

While neither actually bother to use google to find what the active constituents of ACV might be, the BBC do actually make a trial in humans and measure the results in a lab.                                                                                             

https://www.health.harvard.edu/blog/apple-cider-vinegar-for-heartburn-2018032813530

https://www.bbc.com/news/magazine-37229792

It looks like if you have high triglycerides, or indeed high blood glucose, ACV is a potentially interesting non-drug therapy.

The guys at Harvard should watch the BBC and try a little harder next time.

Conclusion

Apple cider vinegar (ACV) is one home remedy that now has some science to support it. It is cheap and easy to access.

It is perhaps not relevant to many people with autism, but does show how medicine turns a blind eye to some old treatments that were stumbled upon as being effective hundreds of years ago.

When it comes to chemoprevention, the majority of cancers in males (prostate, colon, esophagus, bladder etc) have been shown in the research to be inhibited by statins. Some people know they have a familial risk of one or more of these cancers, would it not make sense that they be informed about chemoprevention?  It is much better to avoid cancer than to have to try to treat it.  In colon cancer it appears that phloretin from ACV might even be helpful.

We also saw that people with type 2 diabetes often find the beta cells in their pancreas die and so they stop making insulin, and yet a cheap calcium channel blocker can protect those insulin-producing cells and put off the day that insulin injections are required.

I did actually borrow my “polypill” name for my son’s autism therapy from another polypill that was designed to extend the healthy life expectancy of older people. Their pill has not been a huge success.

What is needed is a personalized polypill, whether it is for people with autism or typical adults from the age of 50.

I imagine, in 50 years time, when your family doctor has your genome on file, you probably will have a personalized little pill to help you minimize the risk of developing preventable disease. 

Modulation of IP3 receptors in Autism – Pancreatitis and Caffeine?

This post stems from our Greek reader Petra's original observations about the combined effects of coffee and bumetanide.

In earlier posts we learned that one likely nexus in autism is the IP3 receptor that releases calcium from a store within each cell.

It turns out that too little/too much activity from IP3 receptors is a feature of a wide range of disease, some of which you may not have heard of, including:-

·      Gillespie syndrome, a genetic condition leading to MR/ID, ataxia and notably part of the iris to be missing

·      Spinocerebellar ataxias, genetic conditions that cause loss of movement control

·      Glioblastoma, an aggressive and “untreatable” brain cancer

·      Alzheimer’s disease

·      Huntington’s disease

·      Pancreatitis, inflammation of the pancreas where your body makes its digestive enzymes and insulin 

For detail, refer to this Japanese paper:- 

IP3 receptor mutations and brain diseases in human and rodents

Of the three types of IP₃Rs, the type 1 receptor (IP₃R1) is dominantly expressed in the brain and is important for brain function. Recent emerging evidence suggests that abnormal Ca²⁺ signals from the IP₃R1 are closely associated with human brain pathology. In this review, we focus on the recent advances in our knowledge of the regulation of IP₃R1 and its functional implication in human brain diseases, as revealed by IP₃R mutation studies and analysis of human disease‐associated genes. 

I suspect that both hyper and hypo-active IP3 receptors will be found in different types of autism. I assume the variant I deal with in my son is more likely to be hyperactive. The research by Gargus suggested “dysregulated IP3R” in autism in 3 single gene autisms; he found depressed Ca²⁺ release through inositol trisphosphate receptors (IP₃Rs) in patient-derived fibroblasts.

Shared functional defect in IP3R-mediated calcium signaling in diverse monogenic autism syndromes

Your body contains a lot of calcium, but almost all of it is in your bones, as calcium phosphate.  Only the residual amount (about 1%) of calcium is present in solution as the ion Ca²⁺. Ca²⁺ plays an important role in many physiological functions.  An excessive elevation of Ca²⁺ inside cells will kill them. Cells must maintain the intracellular Ca²⁺ concentration at the low level of ~10⁻⁷ mol/L, against the much higher extracellular Ca²⁺ concentration (~10⁻³ mol/L).

Cells must be able to rapidly and dynamically change the intracellular Ca²⁺ concentration in response to extracellular stimuli to regulate physiological functions such as cell proliferation, fertilization, immune response, and brain functioning.

To dynamically change the intracellular Ca²⁺ level, cells use two sources of Ca²⁺:

·      Ca²⁺ influx from outside (the extracellular space)

·      Ca²⁺ release from inside (the intracellular Ca²⁺ store, the endoplasmic reticulum – ER)

Many Ca²⁺ handling molecules (Ca²⁺ ion channels, Ca²⁺ pumps, Ca²⁺ sequester proteins) work to maintain the correct balance. The IP3 receptor is a key protein in the regulation of the intracellular Ca²⁺ dynamics, because it  controls the release of intracelluar Ca²⁺.

If IP3R is left open, Ca²⁺ levels inside cells become too high; if it is left shut Ca²⁺ becomes too low.

No medical therapy currently exists to inhibit/block IP3 receptors, but today’s post considers one potential therapy – caffeine. 

Caffeine

Caffeine is a drug, although it is not regulated as one.  At high doses caffeine is toxic, but at non-toxic doses caffeine does have some potent medical effects and it does protect against certain diseases.

It protects against pancreatitis, for example.

It would be very hard to drink yourself to death with coffee. Just like eating numerous bananas does not cause death by having too much potassium in your blood. Supplements have more risks than food. 

Pancreatitis IP3R and Caffeine 

Caffeine protects against experimental acute pancreatitis by inhibition of inositol 1,4,5-trisphosphatereceptor-mediated Ca2+ release 

Significance of this study

What is already known on this subject?

·       Acute pancreatitis is a major health problem without specific drug therapy.

·       Coffee consumption reduces the incidence of acute alcoholic pancreatitis.

·       Caffeine blocks physiological intracellular Ca²⁺ oscillations by inhibition of inositol 1,4,5-trisphosphate receptor-(IP₃R)-mediated signalling.

·       Sustained cytosolic Ca²⁺ overload from abnormal Ca²⁺ signalling is implicated as a critical trigger in the pathogenesis of acute pancreatitis.

What are the new findings?

·       Caffeine and its dimethylxanthine metabolites inhibit IP₃R-mediated, sustained cytosolic Ca²⁺ elevations, loss of mitochondrial membrane potential and necrotic cell death pathway activation in pancreatic acinar cells.

·       Neither specific phosphodiesterase inhibitors nor cyclic adenosine monophosphate and cyclic guanosine monophosphate inhibit sustained Ca²⁺ elevations in pancreatic acinar cells.

·       Serum levels of xanthines after 25 mg/kg caffeine administration are sufficient to inhibit IP₃R-mediated Ca²⁺ overload in experimental acute pancreatitis.

·       Caffeine but not theophylline or paraxanthine administered at 25 mg/kg significantly ameliorated pancreatic injury in experimental acute pancreatitis through IP₃R-mediated signalling inhibition.

How might it impact on clinical practice in the foreseeable future?

·       These findings support an approach of inhibition of Ca²⁺ overload and of its consequences as novel potential therapy for acute pancreatitis.

·       Methylxanthine-based structures are suitable starting points for drug discovery and development to treat acute pancreatitis. 

The Pancreas and Autism

The biomarker proposed by Joan Fallon/Curemark for her autism treatment (CM-AT) is low fecal chymotrypsin level. Chymotrypsin is a digestive enzyme produced in the pancreas and it can be used as a test for early cystic fibrosis. In adults low chymotrypsin indicates a pancreatic disease like pancreatitis.

Many people with autism have GI problems, but there are several distinct sub-groups. Some people have inflammatory bowel disease (IBD) potentially leading to ulcerative colitis, but most do not. Some people with autism have GI dysfunctions that remain undiagnosed, for some it is as if they do not digest food the same way as other people.

If IP3R hyperactivity is a feature of some autism and IP3R hyperactivity is inherent in pancreatitis, is it a surprise that some people with autism do not seem to digest their food properly? Or is it just a coincidence?

Brain Cancer

We did come across glioblastoma in a previous post that looked at off-label therapies for some cancers. In that post we came across an academic from San Diego, who decided to read the research and try and reverse his incurable aggressive brain cancer. This involved driving across the border to Mexico to freely acquire the prescription drugs he used to treat himself.  Two decades later he is still very much alive. 

More Wnt Modulation for Autism and More Inexpensive Potential Cancer Therapies

According to the study below, a hot cup of strong Greek coffee might be a good choice to maintain Professor Williams in good health.

Caffeine-mediated inhibition of calcium release channel inositol 1,4,5-trisphosphate receptor subtype 3 blocks glioblastoma invasion and extends survival.

IP₃Rs are known to be difficult to study especially due to the lack of suitable inhibitors and subtype specific blockers. We found that caffeine paradoxically inhibited IP₃R-mediated Ca²⁺ responses in a subtype 3 specific manner (Figure 5). Using caffeine as a tool to inhibit IP₃R3-mediate Ca²⁺ release, we have demonstrated that inhibiting IP₃R3 effectively reduced the migration, invasion, and survival of glioblastoma cells (Figure 2). The gene silencing of IP₃R3 by shRNA also effectively reduced the caffeine sensitivity of Ca²⁺ signaling and invasiveness in the Matrigel invasion assay (Figure 5). Our results are the first to demonstrate the involvement of IP₃R3 in glioblastoma Ca²⁺ signaling and invasion. Furthermore, we suggest that IP₃R3 can be specifically targeted for therapeutic intervention in glioblastoma patients with minimal influence on normal glial as well as neuronal functions.

Whether caffeine can directly affect the gating of IP₃R3 channels or not is still unknown. However, according to previous studies demonstrating that caffeine can compete with ATP binding to IP₃Rs (21) at millimolar concentrations (20), caffeine could selectively bind to IP₃R3 and affect the gating of IP₃R3. Further work is required to investigate the direct role of caffeine on IP₃R3 gating in comparison to other subtypes of IP₃R.

In summary our study provides IP₃R3 as a novel therapeutic target for glioblastoma treatment. Our study also provides new insights into the detailed molecular mechanism of caffeine action on migration and invasion of glioblastoma. The apparent beneficial effect of caffeine suggested by our study should trigger future investigations of the therapeutic potential for caffeine to treat this deadly disease that otherwise has no cure. 

Conclusion

Caffeine is the most obvious modulator of IP3R in your kitchen or at the local pharmacy.

cAMP plays a complex role in IP3R, PKA is involved so PDE4 should be. Parathyroid hormone (PTH) is also important. PTH is secreted to tell your bones to release Ca²⁺ into the bloodstream, but it has multiple roles. PTH causes the release of IP3 and DAG and hence release of calcium from the store within cells (the ER). PTH release is stimulated when Ca²⁺ is low but also by other things, such as notably by histamine. PTH also is reported to increase the sensitivity of IP3R receptors, so too much PTH would clearly be a bad idea.

Primary Hyperparathyroidism (PHPT) is characterized by hypercalcaemia and elevation of parathyroid hormone.  Children with PHPT may present with non-specific complaints such as behavioural change and deteriorating school performance.  As we know, behavioural change in the form of aggression sometimes occurs in autism, ADHD and various other mood disorders. It may also present as a psychiatric manifestation of an endocrine disorder such as Primary Hyperparathyroidism (PHPT).

It is not surprising that histamine can cause aggression in the same way that Primary Hyperparathyroidism does. Aggression in all psychiatric disorders very likely has a biological cause, you just have to look for it. 

Aggression and Homicidal Thoughts in a Patient with Primary Hyperparathyroidism: A Case Report.

How about checking kids with aggression/SIB for PHPT, or just high levels of calcium (hypercalcaemia). Or perhaps:-

Going Loco? Think histamine, calcium and hyper-parathyroidism, before taking antipsychotics.

Back to caffeine.

In people with hyperactive IP3 receptors, such as those who damaged their pancreas by drinking too much alcohol, caffeine looks a smart therapy. The same would apply to people with autism and hyperactive IP3 receptors. So for those people, drink coffee, preferably Greek coffee (or Turkish coffee, which is the same thing). Some Latin American countries also make potent coffee drinks. Your cup of instant coffee, or chain store coffee is not going to do much.

There are numerous interesting substances in less processed coffee, not just caffeine. The key is to process it as little as possible, as we saw cocoa. In instant coffee only the caffeine is going to have much effect.

Chlorogenic acid, an OAT3 inhibitor, that should enhance bumetanide, is there in coffee.

Coffee contains small amounts of Caffeic acid. What we would really like is Caffeic Acid Phenethyl Ester (CAPE), which is a substance found in some bee propolis. CAPE acts as a PAK1 inhibitor, among other potentially beneficial effects.

Catechin, epicatechin, and surprisingly vanillin are present in coffee.

Roasting coffee makes big changes to its chemical composition and of course to its taste. Green coffee bean extract, used as a supplement for weight loss, is a rich source of chlorogenic acid.

Perhaps someone should do a study on adults with autism using 2 cups of Greek coffee a day.  Alternatively you could just use caffeine pills, with or without coffee bean extract for those interesting flavanols.

OAT3 inhibitors for Bumetanide - Probenecid, but also Aspirin, Chlorogenic acid (Coffee), Epicatechin (Cocoa, Cinnamon) and more.

Today’s post is about OAT3, highlighted by the green lines.
The interventions reduce renal excretion and raise plasma
concentration rather than directly improving transport across the BBB

Today’s post is a collaboration. Our reader Ling pointed out research trying to boost the bioavailability of bumetanide using something clever called an OAT3 inhibitor.  This would reduce the rate at which the body excretes bumetanide and thus potentially improve its therapeutic effect.

Petra, our reader from Greece, pointed out that in her son Bumetanide seemed to work better when taken with Greek coffee and that that Greek Grandpas like to take their diuretics with a steaming Greek coffee.

Most people, me included, automatically think caffeine when someone mentions coffee.

So I assumed that caffeine might be an OAT3 inhibitor and I did make some experiments on that basis. There is no research data to support caffeine as an OAT3 inhibitor.

Recently I was again looking for other potential Bumetanide boosters.  The obvious one is called Probenecid.  Probenecid is used to treat gout because it lowers uric acid.

Aspirin has some odd effects; low dose aspirin will raise uric acid, but high dose aspirin will lower it. Aspirin is an OAT3 inhibitor.

OATs are a very niche subject, to add to the confusion sometimes you are better looking for SLC22A8, the gene that encodes the transporter. 

There was an earlier post on this subject, which showed that many NSAIDs inhibit OAT3, including Knut’s favourite Ponstan. They are not so well suited to continued use.

Boosting Bumetanide with an OAT3 Inhibitor?

At the end of my little investigation I figured it out; there are many OAT3 inhibitors available, including some in your kitchen.  

Key points on OAT3 (Organic Anion Transporter 3)

If you want to increase the peak concentration and indeed the half-life of a drug that is excreted from the body by OAT3 (organic anion transporter 3), an OAT inhibitor is what you need.

The drug Probenecid is by far the best known OAT3 inhibitor and it is very potent. It has long been to boost the performance of penicillin type antibiotics to treat tough bacterial infections.

Probenecid, if available, may very well be the ideal bumetanide booster.

For adults a simple option is Greek/Turkish coffee. I see little downside as long as you can handle the caffeine. The Greeks live a long time and drink plenty of coffee.

For those who do not like caffeine you can go to active components within the coffee, which seem to be the chlorogenic acids (1,3- and 1,5-dicaffeoylquinic acid). They are sold as a weight loss supplement, the long established version is the French-made Svetol, but there are now others. They still contain 2- 3% caffeine.

Epicatechin, found in cinnamon, dark chocolate and high flavanol cocoa is another OAT3 inhibitor. Cocoavia, made by Mars, is used by some readers of this blog. Cocoa flavanols do clever things with nitric oxide (NO) and have been shown to improve mild cognitive impairment (MCI) and heart health by improving blood vessel elasticity.

Catechins are flavanols belonging to a family of closely related compounds, such as epicatechin, epigallocatechin, epicatechin gallate (EGC), and epigallocatechin gallate (EGCG). They are all slightly different. Catechin itself is not an OAT3 inhibitor; EGCG may or may not be.

Low dose aspirin is likely the cheapest OAT3 inhibitor. It also increases peripheral circulation, which could benefit some. Low dose aspirin has the downside of a small bleeding risk, mainly in old people, and there is a risk of Reye’s syndrome if given during/after a viral infection.

I think for adults a Greek coffee may be the best. For people who have a profound benefit from Bumetanide, I think they should look into Probenecid.

Personally I think Svetol is worth a try.

Coffee that has been extensively processed (just as we saw with cocoa) may not have the same chlorogenic acid content as the more gritty coffee used in the Balkans. Coffee consumption is actually associated with many neurological benefits, reducing the incidence of Parkinson’s and Alzheimer’s; the common mistake in research is the assumption that the effect must be from caffeine.

Source: Can coffee consumption lower the risk of Alzheimer’s disease and Parkinson’s disease? A literature review

  

The health effects of decaffeinated Coffee

My eureka moment in this post was reading about gout and coffee and then decaffeinated coffee. 

Coffee Itself, Not Caffeine, Reduces Risk of Gout 

Dietary supplementation with decaffeinated green coffee improves diet-induced insulin resistance and brain energy metabolism in mice. 

Decaffeinated Green Coffee Bean Extract Attenuates Diet-Induced Obesity and Insulin Resistance in Mice

So then it was a question of finding what in coffee could be the OAT3 inhibitor. At which point I found a very insightful paper that tells you everything, once you realise that:

Coffee = chlorogenic acids  = 1,3- and 1,5-dicaffeoylquinic acid

Interaction of Natural Dietary and Herbal Anionic Compounds and Flavonoids with Human Organic Anion Transporters 1 (SLC22A6), 3 (SLC22A8), and 4 (SLC22A11)

Five compounds, 1,3- and 1,5-dicaffeoylquinic acid, ginkgolic acids (15 : 1) and (17 : 1), and epicatechin, significantly inhibited hOAT3 transport under similar conditions

3.2. Inhibition of hOAT3 by Natural Anionic Compounds and Flavonoids

Human OAT3 expressing cells showed about 4-fold greater accumulation of ES as compared to background control cells ( versus  pmol mg 10  , resp.). Similar to hOAT1, hOAT3-mediated ES uptake was completely (>96% inhibition) blocked by probenecid (Figure 4). Five of the compounds, 1,3- and 1,5-dicaffeoylquinic acid, epicatechin, and ginkgolic acids (15 : 1) and (17 : 1), significantly inhibited hOAT3-mediated transport at 50-fold excess (Figure 4). 1,3-Dicaffeoylquinic acid and ginkgolic acid (17 : 1) exhibited 41% inhibition, while 30–35% reduction of hOAT3-mediated ES uptake was observed for 1,5-dicaffeoylquinic acid, epicatechin, and ginkgolic acid (15 : 1). Catechin, 18β-glycyrrhetinic acid, and ursolic acid failed to produce significant inhibition. Based on the level of inhibition observed, values for all of these compounds would be greater than 50 μM, much higher than clinically relevant concentrations (Table 1). Therefore, further dose-response studies were not performed.

Lay off the Lycopene?

Lycopene does the opposite of what we want. Too much lycopene may lower the effectiveness of a drug that is excreted via OAT3. 

2.29. Lycopene

Lycopene is a carotenoid pigment found in tomato [94]. Lycopene from dietary sources has been shown to reduce the risk of some chronic diseases including cancer and cardiovascular disorders [95]. The administration of lycopene significantly normalized the kidney function and antioxidant status of CSP-treated animals. Furthermore, lycopene also increased the expression of the organic anion and cation transporters (OAT and OCT, resp.) including OAT1, OAT3, OCT1, and OCT2 in the renal tissues [96–98]. In addition, lycopene also decreased the renal efflux transporters (multidrug resistance-associated protein [MRP]-2 and MRP4) levels and induced Nrf2 activation, which activated the antioxidant defense system [99]. Furthermore, lycopene protected against CSP-induced renal injury by modulating proapoptotic Bax and antiapoptotic Bcl-2 expressions and enhancing heat shock protein (HSP) expression [97].

https://www.hindawi.com/journals/omcl/2016/4320374/                                                                                                                  

Aspirin

I actually started out this post by looking at what dose of aspirin might be effective in inhibiting OAT3.  We do know that Aspirin is indeed an OAT3 inhibitor.  

Aspirin and probenecid inhibit organic anion transporter 3

I did find the answer, but along the way you do end up having to look at uric acid. 

Uric acid is taken up by OAT1 and OAT3 from the blood and reabsorbed into renal tubular cells via URAT1 Uric acid is taken up by OAT1 and OAT3 from the blood and reabsorbed into renal tubular cells via URAT1Uric acid is taken up by OAT1 and OAT3 from the blood and reabsorbed into renal tubular cells via URAT1. 

Uricosuric drugs increase the excretion of uric acid in the urine, thus reducing the concentration of uric acid in blood plasma. 

In general, uricosuric drugs act on as urate transporter 1 (URAT1). URAT1 is the central mediator in the transport of uric acid from the kidney into the blood.  By their mechanism of action, some uricosurics (such as  probenecid) increase the blood plasma concentration of certain other drugs and their metabolic products  – this is their effect on OAT3.

Probenecid is a medication that increases uric acid excretion in the urine.

Atorvastatin is a so-called secondary uricosuric. High dose aspirin should also be called a secondary uricosuric.

Antiuricosuric drugs raise serum uric acid levels and lower urine uric acid levels. These drugs include all diuretics and low dose aspirin. 

Low dose aspirin inhibits OAT1 and OAT3 which reduces urate secretion, but high dose aspirin inhibits URAT1 and reduces urate re absorption. This is sometimes known as the biphasic effect.

So low dose aspirin will increase plasma uric acid, but high dose aspirin has the same effect as Probenecid, it lowers plasma uric acid levels.

So Aspirin and Probenecid both affect URAT1 and OAT3. 

Source: Effects on Uric Acid Metabolism of the Drugs except the Antihyperuricemics

At what dose is Aspirin an OAT3 inhibitor?

If we just want aspirin to inhibit OAT3 and not inhibit URAT1, what dose is effective? Fortunately this has been answered in the research. The typical low dose of aspirin (75mg) used preventatively in older people is OAT3 inhibiting, it raises plasma uric acid.  

THE EFFECT OF MINI-DOSE ASPIRIN ON RENAL FUNCTION AND URIC ACID HANDLING IN ELDERLY PATIENTS

Salicylate

Salicylic acid and its derivatives are the most prescribed analgesic, antipyretic, and anti-inflammatory agents. Salicylates have a “paradoxical effect” on the handling of uric acid by the kidney. The action of salicylates on uric acid excretion depends on the dose of salicylates. At doses of less than 2.5 g/day, salicylates cause the retention of uric acid by blocking the tubular secretion of uric acid, while at dose of higher than 3 g/day, they cause increased urinary excretion of uric acid [70]. Mini-dose aspirin, even at a dosage of 75 mg/day, caused a decrease in uric acid excretion and raised serum uric acid level [71]. It has been suggested that the “paradoxical effect” of salicylate can be explained by two modes of salicylate interaction with URAT1: (1) acting as an exchange substrate to facilitate uric acid reabsorption, and (2) acting as an inhibitor for uric acid reabsorption [72]. Low dose of salicylate interact with OAT1/OAT3, the uric acid secreters [73].

Low dose aspirin leads to decreased renal excretion of uric acid and raised serum uric acid levels, which can cause a gout attack in those predisposed to this condition.

High doses of aspirin lower serum uric acid concentration.

Reye’s Syndrome

In children aspirin is very rarely used because of the risk of Reye’s syndrome. Reye’s syndrome causes severe liver and brain damage. It is a type of severe mitochondrial failure that can occur after a viral infection like flu or chickenpox, but it almost only occurs when aspirin has been prescribed. Nobody knows for sure the exact mechanism of the disease.

So do not give aspirin to children with a viral infection.  We already know to avoid paracetamol/acetaminophen (Tylenol in the US) in babies/children and people with autism. Paracetamol/acetaminophen depletes the body’s key antioxidant GSH. 

If someone overdoses on Paracetamol/acetaminophen you give them a high dose of NAC to prevent death. 

Conclusion

Given how long it takes to develop new drugs, I think that improving the pharmokinetics of bumetanide is a pretty obvious thing to do. 

Diamox is an OAT3 inhibitor and our reader Agnieszka found it beneficial only when administered along with Bumetanide.

Strong coffee is an OAT3 inhibitor and this was found to enhance bumetanide by Petra’s son with Asperger’s.

Cinnamon which contains epicatechin, another OAT3 inhibitor, did seem to be helpful in Monty who also takes bumetanide.

I suspect Diamox may be the most potent OAT3 inhibitor of those three

The interesting OAT3 inhibitors seem to be:-

·        Probenecid

·        Low dose aspirin

·        Epicatechin (cocoa, cinnamon ..)

·        Chlorogenic acids (coffee and decaffeinated green coffee extracts) 

Cinnamon, high flavanol cocoa and indeed coffee (minus the caffeine) have numerous health benefits.

Note that Catechin has no effect on OAT3. EGCG was not tested but in other studies has been shown it does affect.

Interactions of green tea catechins with organic anion-transporting polypeptides.

The logical next step would be to improve bumetanide transport across the blood brain barrier.