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Sunday 24 March 2013

More lessons from Naltrexone and TLR4; Astragalus

The naltrexone story I covered in the last post has turned up other insights into its mode of action in Hepatitis C.

(music: Steely Dan live from 1974)

Most importantly, naltrexone is antifibrotic. TLR4 agonism stimulates the activation of hepatic stellate cells (HSC) into myofibroblasts that lay down collagen-rich matrix all over the place like a one-armed plasterer on meth. A little of this is part of the repair process but excess is like DIY repairs gone bad. Sooner or later there's so much plaster you can't get in or out of your own cells. Hilarity doesn't ensue.

Mechanisms of Hepatic Fibrogenesis

Among the most compelling pathways of injury are those recently uncovered for innate immune signaling in liver. Specifically, the discovery of TLRs has led to major advances in understanding how the human organism responds to pathogens. The identification of TLR4, the receptor for bacterial lipopolysaccharide, on Kupffer cells, was therefore not a surprise, but its expression on stellate cells was unexpected. Moreover, although TLR4 signaling in macrophages may be essential for inflammatory responses, recent studies have indicated that signaling by stellate cells in response to lipopolysaccharide and possibly endogenous ligands of TLR4 (eg, high-mobility group box 1, biglycan, and heparan sulfate) may be more important than in Kupffer cells in eliciting a fibrogenic response by down-regulating bone morphogenic protein (BMP) and activin membrane-bound inhibitor, a transmembrane suppressor of transforming growth factor β1 (TGFβ1), which is the major fibrogenic cytokine in the liver. This finding has converged with evidence that specific single-nucleotide polymorphisms of TLR4 contribute to the rate of fibrosis progression in HCV infection, thereby linking a genetic risk marker to disease pathogenesis.

Naltrexone prevents gliosis (inflammation of neuroglial cells) caused by opiates through TLR4 agonism. HSCs are hepatic glial cells. Glial cells are "caretaker" cells that protect and repair nerves, blood vessels and the like and maintain the appropriate spaces between cells and the extra-cellular matrix. So this link between gliosis and fibrosis doesn't surprise me. Even in the dizzying and scarcely ever linear world of immunology, sometimes the correct answer can be the simplest.

What are the relevant TLR4 agonists in liver fibrosis? Lipopolysaccharide (LPS) from gram-negative bacteria, and alcohol. Opiates too maybe (methadone use is associated with fibrosis in Whites Only in this study, but methadone can always be either substituting for, or encouraging the use of, something worse).

Naltrexone antagonizes TLR4 and increases receptor numbers (decreasing sensitivity).

Naltrexone, an opioid receptor antagonist, attenuates liver fibrosis in bile duct ligated rats

This is the first study to demonstrate that administration of an opioid antagonist prevents the development of hepatic fibrosis in cirrhosis. Opioids can influence liver fibrogenesis directly via the effect on HSCs and regulation of the redox sensitive mechanisms in the liver.
Comparative Study between the Effect of Atorvastatin and Naltrexone on Hepatic Fibrosis Induced by Bile Duct Ligation in Rats (pdf)
Another TLR4 antagonist seems to be the polysaccharide-A from astragalus root. Astragalus is a common Chinese herb which is well-tolerated and used in many anti-inflammatory preparations including liver-protecting and immune-boosting formulas. I like it myself and have had good results with either astragalus alone, or a mixture of astragalus and the super-weird cordyceps fungus, which also contains an active polysaccharide but much else besides.

TLR4 expression in chronic UTI patients after astragalus treatment was higher than pre-treatment.
The pattern with these agents seems to be that sensitivity to "bad" LPS is reduced, but that macrophage activity is enhanced. This should see some clearing of the immune complexes (cryoglobulinaemia) associated with hepatitis C and a reduction in the various extra-hepatic autoimmune symptoms they cause. Hepatic LPS sensitivity is also reduced by the presence of highly-saturated fats in the diet (beef tallow, coconut oil, etc) and the restriction of polyunsaturated fatty acids.

Probiotics (such as the anti-inflammatory Rhamnosus LGG) have a comparable  effect on TLR4: activation after LPS exposure is decreased.
LGG attenuates LPS induced inflammation, and this may be associated with TLR4/NF-κB down-regulation.

Lactobacillus GG Treatment Ameliorates Alcohol-induced Intestinal Oxidative Stress, Gut Leakiness, and Liver Injury in a Rat Model of Alcoholic Steatohepatitis

I think it's a good idea to take probiotics if you have hepatitis C, and the L. Rhamnosus plus Reuterii combination was my favourite long before I knew this TLR immunology stuff.
J Am Coll Nutr. 2012 Feb;31(1):14-23.
Probiotics in the treatment of the liver diseases.
Kirpich IA, McClain CJ.


Division of Gastroenterology, Hepatology and Nutrition, Department of Medicine, University of Louisville, KY 40202, USA.


The concept that interactions between the gut, the liver, and the immune system play an important role in liver diseases is an old concept that has recently seen a resurgence in interest. Altered intestinal bacterial flora and gut-associated endotoxemia are increasingly recognized as critical components in both nonalcoholic fatty liver disease (NAFLD) and alcoholic liver disease (ALD). Probiotics have been proposed in the treatment and prevention of many conditions, including the liver diseases. Probiotics are live microorganisms that, when consumed in adequate amounts, confer a health benefit to the host. There are many mechanisms by which probiotics enhance intestinal health and influence the gut-liver axis, including modulation of the intestinal microflora, modification of intestinal barrier function, and immunomodulation. The present review summarizes the recent studies highlighting the role of the intestinal microflora in the development of NAFLD and ALD and the potential efficacy of probiotics as a therapeutic strategy for liver diseases.

Oh, BTW, what's another TLR4 antagonist? Niacinamide (nicotinamide). I've told you that's antifibrotic in an earlier post, for quite different reasons.
I could go on all day, all year maybe, but I have stuff to do now.
Cordyceps in action (The one in this video is a relative of C. Sinensis, the herbal one, which parasitizes Tibetan moth larvae):


Thursday 21 March 2013

Naltrexone has TLR-4 activity - is it an "Old Friends" mimic?

(Our first song for today is appropriately Junk by The Puddle, a early post on this topic from 1985.)

Naltrexone is a mu-endorphin antgonist that is used as an opioid antagonist. It will reverse intoxication from opioid analgesics and has a longer duration of action than naloxone. Naloxone is preferred in emergency settings because of its faster onset of action, but naltrexone, unlike naloxone, is effective given by mouth, and its long duration of action (10 hrs) makes it a safer treatment for overdose with long-acting opioids such as methadone (24 hrs, but the half-life of methadone can be significantly decreased by urinary acidifiers such as ascorbic acid or citric acid, and is increased by urinary alkalizers such as sodium bicarbonate as methadone has low solubility at high urinary pH). Naltrexone's most common clinical use is in doses of 50mg daily as a maintenance treatment to blockade the addictive effects of both opiates and alcohol. Recently I spoke to an AOD patient using naltrexone in this way and was surprised that they reported that the drug had an anti-depressant effect. This isn't what would we'd expect under the old endorphin receptor model from a full-time blockade; dysphoria would be the predicted side-effect.


A clue lies in the popular off-label use of naltrexone at low doses (3-4.5 mg nocte) as an immune-modulating agent. The Low Dose Naltrexone homepage claims
"FDA-approved naltrexone, in a low dose, can normalize the immune system — helping those with HIV/AIDS, cancer, autoimmune diseases, and central nervous system disorders."
This is not quackery; read the NOLA Hepper blog in the blogroll to your right for a case study of LDN in the treatment of hepatitis C. Naltrexone is some potent juju, but the results have been hard to explain till recently. The mechanism that was originally stated is as followed; endorphin synthesis is highest at night. Blocking receptors for a few hours while the patient sleeps has the effect of elevating endorphin levels; these elevated endorphins have mood and immune-modulating effects. Hormesis in other words.
"The brief blockade of opioid receptors between 2 a.m. and 4 a.m. that is caused by taking LDN at bedtime each night is believed to produce a prolonged up-regulation of vital elements of the immune system by causing an increase in endorphin and enkephalin production. Normal volunteers who have taken LDN in this fashion have been found to have much higher levels of beta-endorphins circulating in their blood in the following days. Animal research by I. Zagon PhD. and his colleagues has shown a marked increase in metenkephalin levels as well."
The endorphin effects of naltrexone are significant of course, but the much higher dose taken by the patient I spoke to could not work in this way; also, both opioid drugs like morphine, and morphine withdrawal states have been found to stimulate HCV replication in vitro.
Recently (c. 2007) studies started to appear showing that opioids and opoid antagonists have TLR-4 activity. TLR-4 is a PAMP (pathogen associated molecular pattern) receptor. TLRs tell  immune cells what type of pathogens they may (or may not) need to get agitated about. In the case of TLR-4 this is gram-negative bacteria, and the ligand is lipopolysaccharide (LPS).
Except that pathogens aren't the only organisms to produce TLR-4 ligands; probiotics, saprophytes and other benign or beneficial bacteria can also have TLR-4 activity, and this exposure is associated with lower rates of auto-immune disease, allergies, depression, cancer and great deal else besides through the "Hygiene hypothesis" or "Old Friends hypothesis" (there are some good articles on this at Emily Deans' Evolutionary Psychiatry blog linked in my blogroll on the right hand side of the page).
The effects we would expect to see from TLR-4 activation by what I might term FAMPs (friend associated molecular patterns) if the Old Friends hypothesis is correct are the same ones attributed to LDN (which increases TLR-4 expression). The illnesses LDN is claimed to treat are all diseases that have come into prominence in the wake of microbiotal extinctions. In many cases they barely seem to have existed prior to the widespread use of antibiotics, disinfectants, and antithelmetics.
2012 Mar;26(3):480-8. doi: 10.1016/j.bbi.2011.12.010. Epub 2012 Jan 5.

Mu opioid receptor activation modulates Toll like receptor 4 in murine macrophages.


Dipartimento di Farmacologia Chemioterapia e Tossicologia medica, Università degli Studi di Milano, Via Vanvitelli 32, 20129 Milano, Italy.


Opioids have been shown to affect both innate and adaptive immunity. We previously showed that morphine affects the macrophage production of pro-inflammatory cytokines after LPS in a NFkB dependent manner.
Toll like receptors (TLRs) play a crucial role in the signaling pathways which lead to NFkB activation. TLR4 is considered the Lipopolysaccaride (LPS) receptor.
The data here presented show that, in murine macrophages, morphine impacts on the immune function acting on the early step of pathogen recognition. Morphine, when added to RAW 264.7 cells and when injected into mice (s.c. 20mg/kg) is in fact able to decrease TLR4 both at mRNA and protein level in RAW cells and peritoneal macrophages. In the same cells, the mu opioid receptor (MOR) antagonist Naltrexone increases TLR4 levels, thus suggesting a role of the endogenous opioid system in TLR4 regulation. The effect of the two drugs is moreover lost in case of co-administration.
Experiments with MOR KO mice and with DAMGO (MOR specific agonist) confirm that the effect of morphine on TLR4 mRNA in peritoneal macrophages is due to the MOR activation. Moreover the effect on TLR4 is blocked by PTX thus indicating the involvement of a G(i) protein after MOR binding. This work unveils a clear link between MOR activation and TLR4, suggesting a new possible mechanism at the basis of the peripheral immunosuppressive effect of opioids.

Make no mistake, this is edge-of-your seat scientific stuff that for my money is predictive of rapid medical progress in unexpected directions. For example: Recent evidence implicates toll-like receptor 4 (TLR4) in opioid analgesia, tolerance, conditioned place preference, and self-administration. In other words, some of the anti-addictive effect of naltrexone blockade is due to its TLR-4 agonism, not its mu-endorphin antagonism (though the two are probably indirectly connected). One obvious implication of this research is that the dose range for both LDN and addiction treatment should probably be much wider. Some people will need larger doses or more frequent dosing for LDN to work, or even smaller doses; VLDN, (0.125-0.250mg) treatment has been used to suport methadone withdrawal; while AOD patients who do not tolerate 50mg naltrexone may well benefit from lower doses. The dose thresholds for endorphin and TLR-4 effects are likely to be different and to vary between indviduals.
Exciting - nay, exhilarating. Sometimes you just gotta love science. It's one of those gifts that just keeps on giving.

(more music - Steely Dan "My Old School")

Thursday 7 March 2013

More Junk Epidemiology - Cataracts and Vitamin C

This study on supplement use hasn't come up on the paleo radar, but it's a good example of how to expose junk epidemiology. It's from the Orthomolecular Medicine News Service - you can subscribe here and it's well worth doing, they don't mail often and are in the process of becoming  accepting of low-carb science (such as ketogenic diets for cancer) while trying to cling to the saturated fat is bad, only vegetables and supplements are healthy message. Because these are not stupid people, and they already have methods that work, it's an interesting struggle to follow. Their archives link is here.
It's another junk study from Sweden - what is it about those Swedes? Is it a case of scientific suevism?
I love that he refers to Bayesian analysis as the way to proceed in these cases. I'm no mathematician, but it makes sense to me.

At the foot of the page I've included an abstract from a review of vitamin C for prevention of Complex Regional Pain Syndrome. This is an impressive result; 0.22 relative risk of this debilitating after-effect of fracture surgery from supplementing 500mg or more ascorbic acid daily for 45-50 days. An unusually effective clinical use for any supplement.
While the authors of the various trials cite the antioxidant effect of ascorbic acid and the toxicity of ROS as a mechanism, I suspect that improved integrity of the collagen matrix in the early stages of bone regrowth might also account for these benefits. After all, that's why ascorbic acid is a vitamin.

Music; Intermezzo from Cavalleria Rusticana by Pietro Mascagni.

Cataracts and Vitamins: The Real Story

by Damien Downing, MBBS, MSB, and Robert G. Smith, PhD
(OMNS Mar 5, 2013) "Hidden danger of everyday supplements is revealed" blared the headline in the UK Daily Mail [1] - a newspaper that is well known for declaring that, for example, "coffee causes cancer" and "coffee reduces cancer risk" on different pages of the same issue. This time it is reporting on a study out of Sweden that appears to show that taking vitamin C or vitamin E supplements increases your risk of developing a cataract - by about 20% for C and 60% for E. [2] It makes a good headline, but does it make sense?

Is this research?

No. They didn't give anybody anything, or do anything to them, This was just a computer exercise in which they re-analyzed postal questionnaires sent to the entire male population aged between 45 and 79 in an area of Sweden, and matched the responses to another database of cataract operations. Although the title says that it is "a population-based prospective cohort study," prospective would really mean that they followed the group of subjects, the cohort, closely over a period of time, without losing many of them. In fact they simply had their computer go through some old electronic records. Nobody was interviewed, and no checks or validation exercises were carried out. No researcher met any of the men in the study, ever.

Is it reliable?

No. The first really serious shortcoming of this paper, the gorilla in the room, is that half the men never replied in the first place, and then the authors deliberately excluded a lot more for reasons such as diabetes - one of the other main "outcomes" of the study and a big risk factor for cataracts. Finally, they omitted to account for another few thousand people, so that in the end they were only studying 27 percent of the original population. If they had randomly selected this sample of the population that would be fine, but in fact the subjects selected themselves by bothering to fill in and return the questionnaire, or not. What were their reasons? We know not. That means that already several types of selection bias have been introduced, and all the results are now meaningless.
There could even be what's known as indication bias - when cause and effect get mixed up. So, for instance, cataracts can take decades rather than years to develop, and people with early symptoms might be more likely to take supplements to ease their eyestrain. If the study goes on entirely in a computer, there's no way of telling.

Is it scientifically plausible?

No. The study contradicts many other studies that have shown either no effect or actual benefits of vitamin C and E for preventing cataracts and other eye diseases. Cataracts are common among older people, and it is well known that antioxidants can reduce the risk of developing them if taken long-term. Smoking, obesity, and diabetes are well-known risk factors for cataracts, and antioxidants are known to prevent the damage caused by these factors. [References below]. In one study, vitamin C supplements taken over 10 years or more reduced the risk of cataracts by about 80%.This is a huge dose-related effect, strongly suggesting the benefit of antioxidants in preventing cataracts. The effect was not apparent for short-term use, suggesting that any shorter-term study may not identify the benefit. (Jacques et al, 1997).
Studies should not be viewed in isolation, because that leads to the "coffee causes cancer" and "coffee reduces cancer risk" absurdity. The effect of a discrepant study such as this is to marginally adjust the current information about risk. Let's say that based on previous studies, as listed below, we thought there was an 80 percent probability that taking vitamins would help to prevent cataracts; after this one we might revise that to 75 percent. This is known as Bayesian probability [after an English minister 300 years ago] and makes a whole lot more sense than the supposedly black-and-white, 95% confidence-interval type of statistics used here. If a gambler isn't a Bayesian he's an idiot; every hand, every throw, alters the odds. So does every study.
The conclusions here are also dodgy because there is no real data on the amounts of the vitamins taken - only a guesstimate from an earlier study of 248 men - and even occasional use was tabulated as use of supplements. For this to make a substantial difference to the health outcome isn't really plausible.

So, in real life?

To prevent age-related diseases of the eye including cataracts, the best current advice is to lower oxidative stress by stopping smoking, reduce excess weight (diabetes again), eat an excellent diet along with a multivitamin supplement and additional supplements of vitamin C (3,000 - 6,000 mg/day in divided doses), vitamin E (400-1,200 IU of natural mixed tocoperols and tocotrienols). This will greatly help prevent oxidation of the tissues of the eye. Artificial forms of vitamin E (dl-alpha-tocopherol) are only 50% as biologically active as the natural form (d-alpha-tocopherol). Taking alpha-tocopherol alone is thought to lower the effective uptake of the other beneficial forms of vitamin E, so it's important to take the natural form of mixed (alpha-, beta-, gamma-, delta-) tocopherols.
(Dr. Damien Downing is a practicing physician specializing in orthomolecular medicine in London, UK, and Dr. Robert G. Smith is a neurophysiologist specializing in eye research at the University of Pennsylvania.)

(I don't have a picture of a Swedish epidemiologist, so here's a Swedish battleship. Technically a Sverige class coastal defense ship, a small battleship of limited speed and range built for defending Sweden's shoreline and harbours.)


2. Selin JZ, Rautiainen S, Lindblad BE, Morgenstern R, Wolk A High-Dose Supplements of Vitamins C and E, Low-Dose Multivitamins, and the Risk of Age-related Cataract: A Population-based Prospective Cohort Study of Men (2013) American Journal of Epidemiology, published online. DOI: 10.1093/aje/kws279

Vitamin C lowers cataract risk:

Head KA. Natural therapies for ocular disorders, part two: cataracts and glaucoma. Altern Med Rev. 2001 Apr;6(2):141-66. [vitamin C alone or with vitamin E reduces risk of cataracts]
Jacques PF, Taylor A, Hankinson SE, Willett WC, Mahnken B, Lee Y, Vaid K, Lahav M. Long-term vitamin C supplement use and prevalence of early age-related lens opacities. Am J Clin Nutr. 1997 Oct;66(4):911-6. [Huge effect, 77% - 83% decrease in lens opacities]

Vitamin E lowers cataract risk:

Rouhiainen P, Rouhiainen H, Salonen JT. Association between low plasma vitamin E concentration and progression of early cortical lens opacities. Am J Epidemiol. 1996 Sep 1;144(5):496-500.
Nourmohammadi I, Modarress M, Khanaki K, Shaabani M. Association of serum alpha-tocopherol, retinol and ascorbic acid with the risk of cataract development. Ann Nutr Metab. 2008;52(4):296-8. doi: 10.1159/000148189.
Seth RK, Kharb S. Protective function of alpha-tocopherol against the process of cataractogenesis in humans. Ann Nutr Metab. 1999;43(5):286-9.
Engin KN. Alpha-tocopherol: looking beyond an antioxidant. Mol Vis. 2009;15:855-60. [ vitamin E likely plays a role in preventing cataracts]

Smoking increases risk:

Mosad SM, Ghanem AA, El-Fallal HM, El-Kannishy AM, El Baiomy AA, Al-Diasty AM, Arafa LF. Lens cadmium, lead, and serum vitamins C, E, and beta carotene in cataractous smoking patients. Curr Eye Res. 2010 Jan;35(1):23-30. doi: 10.3109/02713680903362880.
Hiller R, Sperduto RD, Podgor MJ, Wilson PW, Ferris FL 3rd, Colton T, D'Agostino RB, Roseman MJ, Stockman ME, Milton RC. Cigarette smoking and the risk of development of lens opacities. The Framingham studies. Arch Ophthalmol. 1997 Sep;115(9):1113-8.

Healthy diet prevents cataracts:

Mares JA, Voland R, Adler R, Tinker L, Millen AE, Moeller SM, Blodi B, Gehrs KM, Wallace RB, Chappell RJ, Neuhouser ML, Sarto GE; CAREDS Group. Healthy diets and the subsequent prevalence of nuclear cataract in women. Arch Ophthalmol. 2010 Jun;128(6):738-49. doi: 10.1001/archophthalmol.2010.84.
Williams DL. Oxidation, antioxidants and cataract formation: a literature review. Vet Ophthalmol. 2006 Sep-Oct;9(5):292-8.

 2013 Jan-Feb;52(1):62-6. doi: 10.1053/j.jfas.2012.08.003. Epub 2012 Sep 15.

Efficacy and safety of high-dose vitamin C on complex regional pain syndrome in extremity trauma and surgery--systematic review and meta-analysis.


Texas A&M Health and Science Center, College of Medicine, Temple, TX, USA.


Complex regional pain syndrome (CRPS) is a devastating condition often seen after foot and ankle injury and surgery. Prevention of this pathology is attractive not only to patients but also to surgeons, because the treatment of this condition can be difficult. We evaluated the effectiveness of vitamin C in preventing occurrence of CRPS in extremity trauma and surgery by systematically reviewing relevant studies. The databases used for this review included: Ovid EMBASE, Ovid MEDLINE, CINAHL, and the Cochrane Database. We searched for comparative studies that evaluated the efficacy of more than 500 mg of daily vitamin C. After screening for inclusion and exclusion criteria, we identified 4 studies that were relevant to our study question. Only 1 of these 4 studies was on foot and ankle surgery; the rest concerned the upper extremities. All 4 studies were in favor of this intervention with minimal heterogeneity (Tau(2) = 0.00). Our quantitative synthesis showed a relative risk of 0.22 (95% confidence interval = 0.12, 0.39) when daily vitamin C of at least 500 mg was initiated immediately after the extremity surgery or injury and continued for 45 to 50 days. A routine, daily administration of vitamin C may be beneficial in foot and ankle surgery or injury to avoid CRPS. Further foot and ankle specific and dose-response studies are warranted.