Showing posts with label KCa3.1. Show all posts
Showing posts with label KCa3.1. Show all posts

Monday, 23 February 2015

Nystatin in autism - a potent Potassium Channel Kv1.3 blocker (anti-inflammatory) or an antifungal/candida treatment?

Today’s post will go against some people’s understanding of autism and inflammatory bowel disease.

Just as there is a belief that heavy metals are a problem in autism there is another is another belief that candida is involved in autism and indeed inflammatory bowel disease (IBD).  Various types of IBD are highly comorbid with autism, but most people with IBD do not have autism.
The most common treatment for candida is an antifungal medicine called nystatin.  This drug is a cheap and widely available.

But nystatin has another property, it is a highly effective blocker of the potassium channel Kv1.3.

Regular readers will recall that this ion channel is key mediator in the inflammatory process, it is a target in many inflammatory conditions such as IBD and indeed autism.  Those little helminths (TSO) parasites that are being researched for both autism and IBD were found to reduce inflammation by releasing their own Kv1.3 blocker which stops the host (human or animal) from rejecting them.

Abstract: Background: Autism children were reported to have gastrointestinal problems that are more frequent and more severe than in children from the general population. Although many studies demonstrate that GI symptoms are common in autism, the exact percentage suffering from gastrointestinal (GI) problems is not well known, but there is a general consensus that GI problems are common in autism. The observation that antifungal medications improve the behavior of autism children, encourage us to investigate their intestinal colonization with yeasts. Aim of the work: The purpose of this work was to investigate the intestinal colonization with yeasts in autistic patients and to assess the role of yeast as a risk factor to cause autism behavior. Patients and methods: The study included 83 cases diagnosed as autistic children referred from the neuro-pediatric clinic and 25 normal children as a control group. All children under the study came to Phoniatric clinic, during the period from 2010 to 2012, complaining of delayed language development with autistic features. Children in this study were classified into 2 groups; control and study groups. All children were subjected to interview, E.N.T examination, language assessment, Childhood Autistic Rating Score (CARS), stool culture for Candida albicans, complete audiological and psychometric evaluation. Results: There was significant relation between the autistic children and heavy growth of Candida albicans in stool culture. Conclusion: The high rate of Candida albicans intestinal infection in autistic children may be a part of syndrome related to immune system disorders in these patients.

Conclusion: Candida albicans infection may be a part of syndrome related to the immune system and depends on genetic basis of autism, or Candida albicans may be etiological factor lead to excessive ammonia in gut which is responsible of autistic behavior in children. More researches are needed to clarify the exact mechanism by which Candida albicans affects autistic children.

In another study the results were not so clear:-

This study was done by James Adams (of the Autism Research Institute, former home of DAN).  According to Wikipedia, Adams' research has been described as "a laundry list of autism woo"; I think he is well intentioned.

You would have expected him to find Candida, but he did not. 

Note that they did not find any parasites either, although they did give up testing after the first 20 results were negative (not very scientific, I think).  Regular readers will know that some “holistic doctors” insist that parasites are the cause of autism.


The presence of yeast was determined by both culture and by microscopic observation. Yeast was only rarely observed by culture in the autism or typical groups, and the difference between the two groups was not significant, as shown in Table Table5.5. Yeast was more commonly observed microscopically, but again the difference between the two groups was not significant.


The parasitology test was used on the first 20 autism samples only, which were all negative. It was then decided to do no additional testing on other samples

The finding that yeast levels were similar in both the autistic and control group is interesting, as there has been a great deal of speculation that yeast infections are a major problem in autism. Our data indicates that yeast is present at normal levels in the stool of this group of children with autism. A study by Horvath and Perman [21] reported that 43% of children with autism undergoing endoscopies had a positive fungal culture for yeast in their duodenal juice, vs. 23% of age-matched controls with other gastrointestinal problems requiring endoscopies. Since their study involved children with severe enough symptoms to warrant endoscopies, the greater symptom severity may explain some of the difference with our study. Since the survey by the Autism Research Institute of over 25,000 parents' reports that parents find antifungals to be one of the most effective medications for improving behavior [44], our findings are puzzling. It is possible that children with autism are more sensitive to even a normal level of yeast. Also, it is possible that antifungals have other effects, such as reducing inflammation.

Which Study to believe?

I have to say that I give more credence to the first study, which is from Egypt.

I think that autism in Egypt is likely to be the “real deal”.  People with severe autism will likely have associated auto-immune/inflammatory conditions and this will include abnormal GI conditions.

Also, the more severe the autism, the more restrictive the diet is likely to be, which will affect what grows inside the intestines.   

Ion Channels and Channelopathies

Ion channels are complex, but fortunately there are not that many of them, unlike genes.

A good source of information is provided by École polytechnique fédérale de Lausanne, on the banks of lake Geneva.  On their Channelpedia site you can see a nice entry on the potassium channel Kv1.3.  It may all look rather too complicated, but there under the Scorpion toxin, is a very common drug, Nystatin.



MbCD and MbCD/C


Leukocyte Subunits effect Kv1.3

Cluster at C-terminus

Kv1.3 associates with Kv1.5

Kv1.3 forms heteromeric channels

Scorpion toxin ADWX-1 is a pore blocker of Kv1.3 channel without affecting its kinetics


The concentrations for nystatin and its structural analog, amphotericin B, required to produce half maximal inhibition (IC50) of the current were estimated to be about 3 and 60 microM, respectively. The effects of nystatin on the amplitude and inactivation of Kv1.3 currents were not voltage-dependent. In inside-out patches, tetraethylammonium (TEA) produced a rapid block of Kv1.3 currents upon the onset of a voltage pulse, while the inhibition by nystatin developed slowly. When co-applied with TEA, nystatin potentiated the extent of the TEA-dependent block, and the kinetic effect of nystatin was slowed by TEA. In summary, nystatin, a compound frequently used in perforated patch recordings to preserve intracellular dialyzable components, specifically inhibited the potassium channel Kv1.3 at concentrations well below those required for perforation

KCa3.1 is related to acute immune responses and Kv1.3 is related to chronic immune responses, the combined administration with Kv1.3 and KCa3.1 inhibitors is likely to enhance their effects in autoimmune disorders or graft rejection

We know that Kv1.3 is widely expressed in the brain, but is it expressed in the intestines of people with inflammatory/auto-immune conditions?

We do not have far to look and since we know that ulcerative colitis is comorbid with autism, we can stick with that



Potassium channels, KV1.3 and KCa3.1, have been suggested to control T-cell activation, proliferation, and cytokine production and may thus constitute targets for anti-inflammatory therapy. Ulcerative colitis (UC) is a chronic inflammatory bowel disease characterized by excessive T-cell infiltration and cytokine production. It is unknown if KV1.3 and KCa3.1 in the inflamed mucosa are markers of active UC. We hypothesized that KV1.3 and KCa3.1 correlate with disease activity and cytokine production in patients with UC.


Mucosal biopsies were collected from patients with active UC (n=33) and controls (n=15). Protein and mRNA expression of KV1.3 and KCa3.1, immune cell markers, and pro-inflammatory cytokines were determined by quantitative-real-time-polymerase-chain-reaction (qPCR) and immunofluorescence, and correlated with clinical parameters of inflammation. In-vitro cytokine production was measured in human CD3(+) T-cells after pharmacological blockade of KV1.3 and KCa3.1.


Active UC KV1.3 mRNA expression was increased 5-fold compared to controls. Immunofluorescence analyses revealed that KV1.3 protein was present in inflamed mucosa in 57% of CD4(+) and 23% of CD8(+) T-cells. KV1.3 was virtually absent on infiltrating macrophages. KV1.3 mRNA expression correlated significantly with mRNA expression of pro-inflammatory cytokines TNF-α (R(2)=0.61) and IL-17A (R(2)=0.51), the mayo endoscopic subscore (R(2)=0.13), and histological inflammation (R(2)=0.23). In-vitro blockade of T-cell KV1.3 and KCa3.1 decreased production of IFN-γ, TNF-α, and IL-17A.


High levels of KV1.3 in CD4 and CD8 positive T-cells infiltrates are associated with production of pro-inflammatory IL-17A and TNF-α in active UC. KV1.3 may serve as a marker of disease activity and pharmacological blockade might constitute a novel immunosuppressive strategy.

So now we have some evidence that Kv1.3 is involved in the inflammatory response within the intestines of people with inflammatory bowel disease (IBD).

Now we just need to look at what happens when you give Nystatin to people with IBD.

Since we do have to link all this back to Candida, let us look for people with IBD claiming that the problem was all about Candida.

If you google Crohns disease (a type of ulcerative colitis/IBD) you will find numerous reference to the benefit of Nystatin and again the assumption that “yeast overgrowth” is somehow the cause of the disease.  Lots of "holistic" doctors etc.

Why do so many people with autism benefit from Nystatin?

We have seen why some people with GI inflammation should find Nystatin very helpful, it will act locally as an immuno-suppressant.  

By reducing this inflammation there will be a reduction in inflammatory cytokines like IL-6.  But the whole idea of Nystatin being safe for children with autism is that it does not enter the blood stream, in stays inside the intestines.

Leaky Gut

Many people subscribe to the notion of the “leaky gut” in autism.  If indeed the gut was leaky, the Nystatin might leak out.  It would then act as a Kv1.3 blocker elsewhere in the body.  It may, or may not, be able to cross the blood brain barrier.

There is now some scientific evidence to show that  “leaky gut” is a real phenomenon.

In people with ulcerative colitis, of course the gut is leaking.  Blood is coming in and therefore other things can flow the other way.

In healthy people, Nystatin will stay almost entirely where it should, within the intestines.  In people with “leaks” it would seem likely that some will leak out.  In these people we might expect a greater effect.

We do know that inflammatory activity within the gut can transmitted elsewhere in the body via the vagus nerve.  This means that reducing inflammation within the GI will reduce the pro-inflammatory signalling sent around the body via the vagus nerve, even with no "leaky gut".  

This may indeed sound very odd, but very promising results are now being found in treating people with arthritis (an inflammatory condition, where IL-6 plays a key role) using implanted electrical devices that affect the vagus nerve.  Vagus nerve stimulation is not pseudoscience, even though it does sound like it should be.

My conclusion

The “father” of ARI and the DAN movement, Dr Bernard Rimland, a research psychologist, suggested that a small proportion of people diagnosed with autism had nothing more than an overgrowth of candida, caused by the frequent use of antibiotics.

It does seem that very many things can lead to “autism” and this diagnosis is now equally applied to people with very mild symptoms and those with debilitating ones.  I imagine that Bernie may indeed have been right; in a small number of people the problem may indeed be yeast.  However, given the relatively large number of people with autism (and IBD) who find Nystatin very helpful, I think the real issue is inflammation and  KV1.3.  The people who respond to Nystatin would very likely also respond to those TSO helminths, and even Stichodactyla toxin (see later).

One problem with regular use of antifungal medication is that you are going to kill off not just the candida.  A healthy gut is supposed have all sorts of things living in it.   

For me, the conclusion is to go back to the ion channels and look not just for KV1.3 blockers but also KCa3.1.  There are plenty of people doing just this, but not for autism, for example:-

Kv1.3 blockers do exist and they include:-

·        Curcumin (problem is low bioavailability)

·        Acacetin (rarely studied and mainly used by bodybuilders)


Under normal conditions in the brain, microglia play roles in homeostasis regulation and defense against injury. However, over-activated microglia secrete proinflammatory and cytotoxic factors that can induce progressive brain disorders, including Alzheimer's disease, Parkinson's disease and ischemia. Therefore, regulation of microglial activation contributes to the suppression of neuronal diseases via neuroinflammatory regulation. In this study, we investigated the effects of acacetin (5,7-dihydroxy-4'-methoxyflavone), which is derived from Robinia pseudoacacia, on neuroinflammation in lipopolysaccharide (LPS)-stimulated BV-2 cells and in animal models of neuroinflammation and ischemia. Acacetin significantly inhibited the release of nitric oxide (NO) and prostaglandin E(2) and the expression of inducible NO synthase and cyclooxygenase-2 in LPS-stimulated BV-2 cells. The compound also reduced proinflammatory cytokines, tumor necrosis factor-α and interleukin-1β, and inhibited the activation of nuclear factor-κB and p38 mitogen-activated protein kinase. In an LPS-induced neuroinflammation mouse model, acacetin significantly suppressed microglial activation. Moreover, acacetin reduced neuronal cell death in an animal model of ischemia. These results suggest that acacetin may act as a potential therapeutic agent for brain diseases involving neuroinflammation.

·        Progesterone (as a hormone, has many other effects)

·        Verapamil (already in the PolyPill)

The most unusual/interesting comes from Cuba:-

Stichodactyla toxin

In humans, a polymorphism in the Kv1.3 promoter is associated with impaired glucose tolerance and with lower insulin sensitivity (11). These results suggest that selective Kv1.3 blockers might have use in the management of obesity and insulin resistance

Because pancreatic beta cells, which have Kv3.2 channels, are thought to play a role in glucose-dependent firing, ShK, as a Kv3.2 blocker, might be useful in the treatment of type-2 diabetes.
You may recall we already saw in this blog the older people taking Verapamil (for heart problems) did not develop type 2 diabetes. According to the table below, ShK toxin is a Kv3.2 blocker in humans, but Verapamil only works in rats.

Since it looks like selective Kv1.3 blockers may prevent/treat obesity, you can expect them to be attractive targets for pharmaceutical companies.  This is a disease of the 21st century.

The spin-off might later be a cost-effective treatment for inflammatory conditions like IBD and autism.

The clever new arthritis treatments, that could be used in autism, are hugely expensive.