Showing posts with label SLOS. Show all posts
Showing posts with label SLOS. Show all posts

Thursday 17 May 2018

Statins, SLOS and Hypocholesteraemia – Going Nowhere Fast

Today’s post is about cholesterol, statins and autism. There is a well-documented condition associated with autism called SLOS (Smith-Lemli-Opitz Syndrome). It is caused by mutations in the DHCR7 gene encoding the enzyme that catalyzes the final step in cholesterol biosynthesis.

Toe syndactyly (webbed toes), one symptom of SLOS

Reduced activity of the enzyme 7DHCR typically leads to low levels of cholesterol, but markedly increased levels of precursor 7DHC (and its isomer, 8DHC) in blood and tissues. Typical SLOS manifestations include intellectual disability, growth retardation, minor craniofacial anomalies, microcephaly and 2-3 toe syndactyly (webbed toes).
SLOS is rare, but some cases do get missed because you can have a DHCR7 mutation and have normal levels of cholesterol and have normal cognitive function.

Cholesterol and the blood brain barrier (BBB)
You do have a lot of cholesterol in your brain, but it does not cross the blood brain barrier (BBB), it was made in the brain.  Eating more cholesterol can have no direct effect on cholesterol levels in the brain.
The standard treatment for SLOS has long been oral cholesterol supplementation, but there is no conclusive research to show it helps. There is plenty of anecdotal evidence.

Simvastatin and SLOS
Simvastatin is a drug widely used drug to treat people with elevated cholesterol.
There has been anecdotal evidence that Simvastatin improves SLOS and recently a very thorough study was carried out to establish whether or not it really has a benefit.
In reality the study was comparing:

Simvastatin + cholesterol supplement  vs  cholesterol supplement

The study was carried out by researchers including Dr Richard Kelley (“Dr Mitochondria”) and Dr Elaine Tierney (“Dr Cholesterol”)

Currently, most SLOS patients are treated with dietary cholesterol supplementation. Although cholesterol therapy reduces serum 7-DHC concentrations to a degree, significant amounts of 7-DHC persist even after years of therapy.  Anecdotal case studies and case series support the idea that cholesterol supplementation benefits the overall well-being of SLOS patients; however, the effects of dietary cholesterol supplementation on cognitive or behavioral aspects of this disorder have not been reported by others or substantiated in a limited controlled trial. The efficacy of dietary cholesterol supplementation is probably limited by the inability of dietary cholesterol to cross the blood–brain barrier. Moreover, increased concentrations of 7-DHC or 7-DHC-derived oxysterol could have toxic effects. Specialists have hypothesized that, in patients with mild to classic SLOS, many aspects of the abnormal behavioral and cognitive phenotype could be the result of altered sterol composition in the central nervous system. Thus, interventions that ameliorate the central nervous system biochemical disturbances in SLOS are critical to understanding the pathological processes that underlie this inborn error of cholesterol synthesis and to developing effective therapies to treat the neurological deficits.

Expression of DHCR7 is regulated by SREBP2, which, when activated by low levels of cholesterol in the endoplasmic reticulum, increases the transcription of most genes of the cholesterol synthetic pathway. Having shown that DHCR7 expression is increased in SLOS fibroblasts treated with simvastatin,31 we hypothesized that the paradoxical increase in serum cholesterol could be the result of increased expression of a DHCR7 allele with residual enzymatic function, and we demonstrated that many DHCR7 alleles encode an enzyme with residual activity. Furthermore, both in vitro experiments with human  fibroblasts and in vivo experiments using hypomorphic Dhcr7T93M/delta mice support the hypothesis that increased expression of DHCR7 alleles with residual enzymatic activity can significantly improve plasma and tissue sterol concentrations. Because residual DHCR7 activity varies among patients with SLOS, this hypothesis could explain the paradoxical increase in cholesterol in some patients and the adverse reactions observed in others.

In this study we also evaluated the potential of simvastatin to alter specific aspects of the SLOS behavioral phenotype. Our secondary outcome measures were the CGI-I and ABC-C irritability scores. Although we observed no significant effect on the CGI-I, we did observe significant improvement in the ABC-C irritability score (Figure 4). This article therefore represents the first controlled study to demonstrate improved behavior in subjects with SLOS in response to a therapeutic intervention.

In summary, this study represents the first controlled trial of simvastatin therapy in SLOS and the first controlled trial demonstrating the potential of drug therapy to modulate sterol composition and to improve behavior in SLOS. We have established that treatment with simvastatin is relatively safe, can decrease DHC levels, and can improve at least one aspect of the behavioral phenotype. These data support continued efforts to identify and rigorously evaluate potential therapies that may have clinically meaningful benefits for patients with SLOS.

Plasma sterol levels

Cholesterol and dehydrocholesterol (7DHC + 8DHC) levels were measured at baseline (B), washout (W, 14 mo) as well as at 1, 3, 6, 9 and 12 months in both the placebo and simvastatin treatment phase. Plasma cholesterol levels (A, B) and DHC (C, D) decreased significantly during the simvastatin phase compared to the placebo phase. The plasma DHC/Total Sterol ratio (E, F), which was the primary outcome measure of this study, also decreased significantly. Data expressed as mean ± SEM.

Hypocholesterolemia (low cholesterol) and some Autism
Ten years ago, Tierney and Kelley published research showing that about 20% of autism is associated with very low cholesterol levels (less than the 5th centile for typical young people) but in their sample of 100, none had an abnormally increased level of 7DHC consistent with the diagnosis of SLOS or abnormal level of any other sterol precursor of cholesterol.

Tierney went on to patent cholesterol as a therapy for autism.

The present invention relates to the field of autism. More specifically, the present invention provides methods for treating individuals with autism spectrum disorder. Accordingly, in one aspect, the present invention provides methods for treating patients with autism spectrum disorder. In one embodiment, a method for treating an autism spectrum disorder (ASD) in a patient comprises the step of administering a therapeutically effective amount of cholesterol to the patient. In more specific embodiments, the ASD is autism, Asperger's disorder, pervasive developmental disorder-not otherwise specified (PDD-NOS), Rett's syndrome and childhood disintegrative disorder. In one embodiment, the patient has autism. 

Tierney has a clinical trial registered that was to start in 2009.

Three sites (Kennedy Krieger Institute [KKI], Ohio State University [OSU], and the National Institutes of Health [NIH]) will collaborate to accomplish the objectives of this study. In addition to defining the frequency of altered cholesterol homeostasis in ASD, 60 youths (20 at each site) with ASD plus hypocholesterolemia will enter a 12-week, double-blind, placebo-controlled trial immediately followed by a 12-week open-label cholesterol trial to test the efficacy of dietary cholesterol supplementation. Outcome measures will include standard tests of behavior, communication, and other autism features.

It appears that the study has not been completed.

Dr. Elaine Tierney and her colleagues are studying different metabolic disorders that can present with autism spectrum disorder through the Autism Metabolic Research Program at Kennedy Krieger. In 2000 and 2001, this group of researchers identified that Smith-Lemli-Opitz-Syndrome (SLOS) is associated with autism spectrum disorder. Since SLOS is known to be caused by a defect in the body's biosynthesis of cholesterol, SLOS may provide clues to the biochemistry of other autism spectrum disorders (ASD).

Dr. Tierney and colleagues published a paper in 2006, in the American Journal of Medical Genetics Part B (Neuropsychiatric Genetics), in which they describe finding that a subgroup of children with ASD have abnormally low cholesterol levels. The children's low cholesterol levels were apparently due to a limited ability to make cholesterol. This finding, in concert with their work with SLOS, has led them to believe that cholesterol may play a role in the cause of some cases of autism spectrum disorder. Dr. Tierney and colleagues at Kennedy Krieger, the National Institutes of Health and Ohio State University are performing a double-blind placebo-controlled study of cholesterol in individuals with ASD.

Cholesterol as a marker of inflammation
Nowadays, hypercholesterolemia and inflammation are considered as “partners in crime”.  Statins do lower bad cholesterol, but they also have broad anti-inflammatory effects.

Arteries do clog up with cholesterol, but a big part of why this happens is inflammation. Cholesterol deposits are initially a protective mechanism, like a band-aid. Treat the inflammation and cholesterol will not need to be deposited.
An altered immune response is a feature of many people’s autism, and you can measure it.
As Paul Ashwood’s research has shown, there are different immune sub-groups that people with autism fall into, and so you could treat each cluster with a specific therapy.

Cholesterol and Thyroid Hormones
Your thyroid produces hormones that control your metabolism. Metabolism is the process your body uses to convert food and oxygen into energy.

Your body converts the circulating pro-hormone T4 into the active hormone T3 locally. So, in your brain T4 has to be converted to T3. If you lack enough T4 coming from your thyroid gland or the special enzyme called D2 you are going to feel lethargic.
Your body needs thyroid hormones to make cholesterol and to get rid of the cholesterol it doesn’t need. When thyroid hormone levels are low (hypothyroidism), your body doesn’t break down and remove LDL (“bad”) cholesterol as efficiently as usual. Elevated LDL cholesterol will show up in your blood tests.
Hyperthyroidism has the opposite effect on cholesterol. It causes cholesterol levels to drop to abnormally low levels.
So best to check thyroid function and cholesterol levels.

My main interest is autism with a tendency to big heads (hyperactive growth signalling pathways) and an overactive immune system. This is the opposite of SLOS and hypocholesterolemia (low cholesterol).
For the 20% with low cholesterol, I think this is a very important biomarker.

.Is supplemental cholesterol the answer? I am not so sure it is.
Hopefully one day soon Dr Tierney, at Kennedy Krieger, will publish her results of cholesterol as a therapy for people with autism and low cholesterol.
For me it is good to see that Simvastatin was well tolerated in a 12 month long trial in children from 4 to 18 years of age. I have the very similar drug, Atorvastatin, in my Polypill.
Interestingly, in a paper that I will cover in later post, increasing HDL (good cholesterol), a feature of Atorvastatin and Simvastatin, was one marker of behavioral improvement in the Ketogenic Diet.

Thursday 30 October 2014

Statins for Cancer and Autism? Another case for PTEN?

When I first started this blog and my investigation into the biology of autism, I did shy away from the more complex areas like genetics.  I assumed that this would be best left to the “experts” and be beyond the powers of those without fancy laboratory tools.

My literature review took me early on to oxidative stress and then neuroinflammation.  I deduced that in the case of neuroinflammation, it might be possible to control inflammatory cytokines using statins.  I also noted the use of statins in TBI (Traumatic Brain Injury). I thought it would be harmless to do a quick trial, not really expecting anything to happen; but it did, and from the very first dose.

The literature is full of references to lipid dysfunction in autism and one large sub-group in autism is known to have high cholesterol.  Cholesterol and inflammation are now known to go hand in hand.  When inflammation is present, the body can react by laying down a protective layer of cholesterol.  The problem is that too much cholesterol is not good for you either.  The real culprit is not the cholesterol, it is the inflammation.

If you are in the high cholesterol autism group, a cholesterol lowering drug that is also anti-inflammatory may be “just what the doctor ordered”.

Be warned that another subgroup in autism has very low cholesterol.  In a study at the Kennedy Krieger Institute, 19% of children had extremely low cholesterol, meaning lower than 99% of typical children.

There is a rare condition, leading to autism called Smith-Lemli Opitz syndrome (SLOS).  SLOS is caused by a mutation in an enzyme involved in cholesterol synthesis; the resulting biochemical characteristics may be predictable. Most patients have lowered plasma cholesterol levels.

Since cholesterol testing is cheap and widely available, you can easily determine which group you are in.

This post is for the high cholesterol cohort.

Note well how meaningless a figure for the "average cholesterol level" in autism would be. In the autism literature they frequently take the mean average for all data, thus missing the point. 

Why Statins for Autism?

My initial logic was that since inflammatory markers are often elevated in autism and that oxidative stress and inflammation are self-reinforcing, it would be logical to find an effective anti-inflammatory agent.  Steroids might fit the bill, but they cause plenty of side effects in long term use; their short term use in autism can be remarkably effective.  So I looked further, and having screened the literature, ended up convincing myself of the potential of statins.  Read all about cytokine storms in the old posts, if you are interested.

I choose  Atorvastatin (also known as Lipitor or Sortis), since it freely crosses the blood brain barrier (BBB) and is safely used my tens of millions of people around the world.

It worked.

Explaining Statin Therapy to others.

The most important thing is to have a therapy that works;  but then you have to explain it to others.

I was recently explaining it again to a doctor relative, who was asking how I could be sure it works.  I explained that every time I stop using it, within a day behaviour changes in the same predictable way.  It is as if people with autism have an inhibitory barrier; there are things they can do, want to do, but something is blocking them from doing them.

Examples are numerous.  Speech being one.  Plenty of kids with autism are non-verbal, everything is physically functional, yet they do not talk, even when they want to communicate.

At the age Monty, now aged 11 with ASD, tried the statin he was relatively verbal.  The immediate change in him was that he suddenly started to play the piano, by himself.  Odd it may sound.

In his earlier years he would often get “stuck”.  He would be upstairs and unable to come downstairs, somebody had to go up and get him.

When I now stop the statin, he will again get “stuck”.  He will stand in the kitchen and want to leave and just say “go that way”, but not move.  You have to take his hand, so that he can “go that way”.

A Better Explanation?

Now I have another explanation of why statins may be effective in one large sub-group of autism.

Statins up-regulate a known key dysfunctional autism gene, and protein, called PTEN.  I mentioned PTEN in a previous post, since one chemical released by eating broccoli also up-regulates PTEN.

Science has already shown that things that down-regulate PTEN (like seizures) make autism worse.

The full science behind PTEN will come in a later post.

Statins and Cancer

Regular readers will recall that PTEN is also a tumor suppressor gene and is therefore a target for cancer research.

Thinking the way I do, I know that statins increase PTEN and that this should slow cancer growth.  Hundreds of millions of people take statins and many millions get cancer, so what about people on statins getting cancer?

A quick check on google and there we have studies showing that people on statins get less cancer and that in common cancers like that of the prostate, the outcome is better when statins are taken.

Now this is not a cancer blog, but you do not have to dig very deep to uncover a wealth of supporting evidence.

In this retrospective cohort of men undergoing RP, post-RP statin use was significantly associated with reduced risk of BCR. Whether the association between post-RP statin use and BCR differs by race requires further study. Given these findings, coupled with other studies suggesting that statins may reduce risk of advanced prostate cancer, randomized controlled trials are warranted to formally test the hypothesis that statins slow prostate cancer progression.

 Conclusions This meta-analysis suggests that statin is associated with a significant risk reduction of liver cancer when taken daily for cardiovascular event prevention. However, this preventive effect might be overestimated due to the exposure period, the indication and contraindication of statins and other confounders. Statins might be considered as an adjuvant in the treatment of liver cancer.

Statins and PTEN

I am no cancer expert, but I can read the literature and the evidence is pretty compelling to me.  It is not enough, however, for doctors to prescribe statins to avoid cancer.  They are so busy prescribing statins to over 50s for other reasons, it does not really matter.

We came across PPAR previously.  PPAR gamma is a pathway to treat type 2 diabetes and the old type 2 diabetes drug Pioglitazone has shown promise in an autism study.

 Effect of pioglitazone treatment on behavioral symptoms in autistic children

At that time I was more interested in PPAR-alpha, due to its role in mast cell stabilization.

It is via PPAR-gamma, that statins up regulate PTEN.

You do not want to overdo it, because at very high doses too much PPAR gamma protein will be produced and you risk causing type 2 diabetes.

Low doses of statins are trouble free for most people, but high doses are associated with increased risk of diabetes and all kinds of aches and pains.

The statin effect in autism does not increase with higher doses, only a small dose is required.

Germline mutations in the tumor-suppressor gene PTEN predispose to heritable breast cancer. The transcription factor peroxisome proliferator-activated receptor-gamma (PPARgamma) has also been implicated as a tumor suppressor pertinent to a range of neoplasias, including breast cancer. We previously demonstrated that lovastatin may signal through PPARgamma and directly upregulate PTEN expression at the transcriptional level. In our current study, we show that simvastatin, pravastatin and fluvastatin can induce PTEN expression in a dose-dependent manner. This resulted from an increase in PTEN mRNA indicating transcriptional upregulation. In addition, we observed, for the first time, that upregulation of sterol response element-binding protein (SREBP), known to induce PPARgamma expression, can increase PTEN expression. Using reporter assays, we observed that both the statins and SREBP could specifically induce PPARgamma-mediated transcription. However, the statins do not appear to signal through SREBP. Furthermore, our results indicate that SREBP utilizes PPARgamma's transcriptional activity to induce PTEN transcription, whereas the statins signal through PPARgamma's protein activity to upregulate PTEN expression. Overall, our observations suggest that statins signal through another transcription factor, in a PPARgamma-dependent manner, which in turn induces PTEN transcription. We, therefore, studied the full-length PTEN promoter through serial deletion reporter assays and electromobility shift assays and identified a region between -854 and -791 that binds an as-yet-unidentified transcription factor, through which the statins induce PTEN expression. Since PTEN is constitutively active, our data indicate it may be worthwhile to examine statin and SREBP stimulation as mechanisms to increase PTEN expression for therapeutic and preventative strategies in cancer, diabetes mellitus and cardiovascular disease

PTEN dysfunction in Cancer and Autism

I will cover this point in more detail in the post on PTEN, but note that the PTEN gene dysfunctions found in 10% of people with autism are generally different to the ones found in cancer.  We also have the difference between whether the PTEN gene is mutated or there is PTEN loss.

There should be two identical copies of the PTEN gene. When one copy is mutated, the protein it produces was found to inhibit the protein produced by the good copy. In other cases, one copy of the PTEN gene is OK, but the other got deleted.   This turned out to be better than having one mutant version.

Different mutations in PTEN are linked to different outcomes.  The known autism mutations are called H118P, H93R and H123Q.  If you have a C124S mutation you would be at risk of something called thyroid follicular carcinoma and not autism.

It is all very complicated and I have to say some conclusions in the research are contradictory.

But it is reported that about 10% of people with autism have an identifiable PTEN mutation.  I am more interested in whether PTEN is an interesting protein in the other 90%.

We saw in the fragile X research that even though this affects only 1% of cases with autism, some experimental therapies for fragile X worked on people with autism, but without fragile X.  At the time I thought that very odd.

My assumption is that PTEN is interesting for more than the 10%.


So there are now 2 plausible reasons why statin therapy may be effective in people with classic autism and elevated cholesterol:-

·        Reduction in inflammatory cytokines 
·        Up-regulation of PTEN

Maybe it is both.

It may be that in people with autism and low cholesterol, and so not suited to statins, they may also have low levels of PTEN.

We saw in a recent post that when you eat fresh broccoli in addition to Sulforaphane, you also produce Indole-3-carbinol (I3C).   I3C also up-regulates  PTEN.

Using Peter logic, if statins have an immediate effect then quite likely so would I3C.

Whatever Next?

Well, for those few of you who have discovered the “magical” beneficial effects of mast cell stabilizers, like Verapamil and Cromolyn Sodium, on both autistic behaviours and severe allergies, here is a preview of what is coming next:-

Recent studies have indicated that PPAR-gamma plays an important role in anti-inflammatory responses and that PPAR-gamma signaling is associated with regulation of PTEN expression. It is known that up-regulation of PTEN expression reduces asthmatic pathogenesis.

These findings suggest that PPAR-gamma uses PTEN to modulate asthmatic responses The signaling mechanism by which stimulation of PPAR-gamma with the agonists regulates PTEN expression as well as Akt phosphorylation remains to be lucidated. However, our results agree with the observation that the anti-inflammatory action of PPAR-gamma agonists is mediated via up-regulation of PTEN.

In other words, increasing PTEN minimizes allergies.  Perhaps, via feedback loops, increasing allergies reduces PTEN?

Seizures also reduce PTEN.

Reduced PTEN leads to increased autistic behaviours.

Not surprisingly we will come back, yet again, to mast cells.

For us, it really does seem that PTEN is a key piece in the puzzle;  but a puzzle with a solution.