Heparin, Growth Factors and Rosacea

Knock-out Mice and FGF Receptor Inhibitors Mimic Rosacea
Heparin Nanofibers Loaded with VEGF and FGF Mimic Stem Cells

In previous articles, I have emphasized the mediation of extracellular signaling by heparan sulfate proteoglycans (HSPGs, polysaccharides attached to proteins) and heparin (HS fragments, oligosaccharides) and the sensitivity of HSPG expression and HS degradation by inflammation.  I return to that subject, spurred on by reading two articles that together show both the significance of heparin-mediated growth factors in general and in the specific case of symptom development in rosacea.

FGF Receptor Inhibitors Cause Symptoms Like Rosacea
Fibroblast growth factors stimulate the development of cancers, and antibodies against FGF receptors block cancer growth (see ref.)  FGF receptor inhibiting antibodies are now being used to stop cancers.  Unfortunately,  FGFR antibodies (e.g. cetuximab, panitumumab) also cause symptoms in the skin (telangiectasia, acneiform eruption) similar to the facial inflammation of rosacea.  Similarly, in knock-out mice, that lack the ability to produce FGFR, there are related symptoms.  It appears that lack of some FGF signaling may produce the symptoms of visible blood vessels and pus-filled (though lacking bacteria) follicles of rosacea.

FGF Mediated by HSPG
FGF binds to the heparan sulfate of membrane bound HSPG in pairs and these FGF dimer/heparan sulfate complexes activate a pair of FGF receptors.  The result is activation of protein phosphorylation activity (tyrosine kinase) and normal skin development.  HSPG synthesis is modified by inflammation and heparanase activity is increased.  This suggests that inflammation will decrease FGF signaling and could lead to symptoms of rosacea.

Growth Factors (VEGF, FGF) Bind to Heparin Nanofibers that Mimic Stem Cells
Stem cells produce lots of different growth factors and when stem cells are introduced into damaged cardiovascular tissue, more healing results (see ref.)  To determine if the growth factors produced by the transplanted stem cells was sufficient for the improved healing, fibers made of heparin were dipped into stem cell cultures and the resulting growth factor-coated fibers were injected into damaged tissue.  The heparin-binding growth factors were just as effective at enhancing healing as were the stem cells in previous experiments.  This demonstrated that heparin-binding growth factors were the key to normal repair/revascularization and function.

Rosacea Results from Inflammation and Aberrant Vascularization
Rosacea is poorly understood and is probably numerous diseases that have related symptoms and complex development.  As I indicated in previous articles, neurotransmitters from stimulated facial nerves, enzymes (kallikrein) and cytokines from intestinal interactions with gut flora, mast cell products (heparin, protease) and modified antimicrobial peptides (cathelicidins), as well as cryptic bacteria in facial tissues, may all be involved.  Inflammation in the skin of the face and in the intestines is involved.  Vitamin D, omega-3 fatty acids and anti-oxidants have a variety of responses (sometimes paradoxical) that differ from individual to individual and at different stages in the development of the disease.  Facial inflammation leads to abnormal development of blood vessels (telangiectasia) and in accumulation of lymphocytes and neutrophils (papulopustular rosacea).

Facial Inflammation May Depress HSPG Production and Disrupt FGF Function
One of the key ramifications of persistent facial inflammation may be the depletion of of HSPGs that normally coat cells.  HSPGs are continually produced, reabsorbed and degraded.  The half-life for HSPGs, even those that surround the cells that produce cartilage in connective tissue, is six hours.  HSPGs are also the source of heparin, that is produced as a counter ion bound to histamine and proteases in the secretory granules released by activated mast cells.  Thus, inflammation-based depression of HSPG production, which is also accompanied by heparanase activation, will remove the HSPG coating of cells.  This HSPG coating is needed for normal growth factor function.  Lack of an HSPG matrix on the surface of cells will also result in the migration of growth factors away from where they are normally functional and into adjacent tissue where they may stimulate aberrant development of blood vessels.  This may explain telangiectasia.

Is Topical Heparin a Rosacea Treatment?
Topical heparin does penetrate the skin.  It would appear to be a logical treatment, if HSPG depletion is contributing to symptom development in rosacea.  The length of the heparin fragments may be important.  I am unaware if anyone has tried the heparin lotions that are available for treatment of wounds to minimize scarring, on rosacea.  Heparin may be useful in combination with vitamin D3 and remediation of gut flora in a general scheme to treat rosacea.

refs:
Segaert S, Van Cutsem E.  Clinical signs, pathophysiology and management of skin toxicity during therapy with epidermal growth factor receptor inhibitors.  Ann Oncol. 2005 Sep;16(9):1425-33. Epub 2005 Jul 12.

Webber MJ, Han X, Prasanna Murthy SN, Rajangam K, Stupp SI, Lomasney JW.  Capturing the stem cell paracrine effect using heparin-presenting nanofibres to treat cardiovascular diseases.  J Tissue Eng Regen Med. 2010 Mar 10. [Epub ahead of print]

Rosacea, Brain Cooling and Niacin Flush

Other players include:  Cathelicidins, Prostaglandins, Cryptic Bacteria, Nerves, Gut

What does it take to make your face red?  Excessive solar exposure can lead to apoptosis of skin cells overloaded with DNA damage and trigger inflammation: vasodilation, recruitment of neutrophils, swelling, etc.  Similarly, a local infection can cause inflammation and the accumulation of neutrophils (see The Inner Life/Extravasation for slide show), lymphocytes, etc., that is observed as pus.  These are general responses that occur in skin anywhere, but the face also blushes in response to emotional cues and flushes with exercise.  Rosacea seems to involve all of these reactions to produce a variety of symptoms of wide severity.  Here I try to provide an overview of the complex physiological interactions involved in rosacea.

Rosacea is Persistent Vasodilation of the Face with Accumulation of Neutrophils

The nervous and circulatory systems of the face are unique and provide numerous triggers for inflammation.  Emotional blushing is a common trait among those who progress to rosacea, even though this type of vasodilation is not easily observed with some facial characteristics.  Thus, many rosaceans claim to have never flushed before their first outbreak, but tests of skin circulation indicate that these individuals had skin types that prohibited display of the blushing.  The face is also adapted to control brain temperature, so changes in body temperature, physical activity, etc. can also trigger flushing.

Facial Blood Circulation to Cool the Brain

The cooling of the blood as it traverses the facial skin is used to cool the brain during extensive exercise or in warm environments.  This unique adaptation also means that control of facial vasodilation can potentially be disrupted in disease and cause symptoms of pathology.  In rosacea,  the brain cooling response is disturbed (see reference below), resulting in persistent vasodilation and suggesting that the unique control of inflammation in the face is why rosacea is limited to the face.  The pattern of blood circulation in the face, however, only roughly approximates the inflammation pattern in rosacea.

Nerves to the Face

The face receives sensory branching from the trigeminal nerve.  The enervation pattern of the branches matches emotional blushing, but they also appear to approximate the pattern of reddening in rosacea.  It makes sense that rosacea involves nerve-triggered dilation of the blood vessels of the face.  One contrast between emotional blushing and rosacea is that emotional blushing does not lead to the offloading of lymphocytes, whereas rosacea produces localization of neutrophils that exacerbate and prolong inflammation.

Cathelicidin, Vitamin D Receptor, DNA Complexes, Autoinflammation

A major component of the innate immune system is the group of basic antimicrobial peptides, cathelicidins.  Cathelicidins are effective against bacteria and they are produced during inflammation and are partially controlled by the vitamin D receptor acting as a transcription factor.  Thus, part of the action of vitamin D in providing protection against disease is by enhancing cathelicidin production.  Cathelicidin action in the skin parallels the control of intestinal villi development by defensins, that are also basic antimicrobial peptides under the control of vitamin D.  Cathelicidins also form complexes with host DNA from damaged cells.  These cathelicin/DNA complexes bind to toll-like receptors (TLRs) and trigger inflammation.  This reaction has been associated with psoriasis and may explain how neutrophil damage can perpetuate inflammation in rosacea.

Niacin Flushing Implicates Arrestins

The unique circulatory system of the face also makes it susceptible to flushing with niacin, a.k.a. nicotinic acid or vitamin B3.  Niacin is cheaper and much more effective at raising HDL and lowering triglycerides and LDL than statins, but is not fully utilized because it also produces intense facial flushes.  A recent article (below) has demonstrated that the lipid benefits can be separated from the flushing and implicated beta-arrestin 1 activation by niacin binding to GPR109A (G-protein-coupled receptor) as the triggering event.  Arrestin, which is involved in clathrin-mediated endocytosis, activates phospholipase A2 that in turn releases arachidonic acid (ARA) from phospholipids.  The ARA (that got into the phospholipids as the omega-6 fatty acid in vegetable oils) is converted by COX-2 into the inflammatory prostaglandin D2.  This prostaglandin is what stimulates vasodilation.  It is possible to produce chemicals that will stimulate the lipid metabolism alterations of niacin, without producing the arrestin activation and inflammation.  Aspirin can be used to inhibit COX-2 and other parts of NFkB-mediated inflammation and eliminate the niacin flush.  It is also interesting that the modified lipid metabolism of schizophrenics also eliminates niacin flushing.  Salicylic acid, the same as the acetylsalicylic acid of Aspirin without the acetate, is also used in some topical applications to quiet the symptoms of rosacea.  Arrestin activation may be involved in rosacea.

Gut Flora, Biofilms and Cryptic Bacteria

The gut is probably involved in most cases of rosacea and bacteria are also implicated by the modification of rosacea symptoms by antibiotics.  This area has not been explored, but I suspect that gut flora controlled by diet, as well as pathogenic biofilms and cryptic bacteria, e.g. Clamydia pneumoneae, in facial tissue are involved in varying degrees in the panoply of pathologies called collectively, rosacea.  Since the bacteria in contact with the gut determine the development of the lymphocytes in the lining of the gut, e.g. Tregs vs. T cells that fight infections, pathogenic gut biofilms may disrupt the normal function of the immune system and support rosacea.  Die off and release of cell wall endotoxin from cryptic bacteria could explain the paradoxical inflammation in response to many treatments that are normally anti-inflammatory.  I have discussed in another article potential approaches to strip off biofilms.

Treatment with Anti-Inflammatory Diet

The Anti-Inflammatory Diet (AID) and Lifestyle that I advocate on this blog would seem to be a natural cure for rosacea.  It should eliminate the inflammatory background that supports rosacea and was probably essential for its development.  This diet also eliminates acne, which is directly related to the accumulation of lymphocytes to make pus.  Inflammation is also needed for the offloading of neutrophils that exacerbate inflammation in rosacea.  Vitamin D is instrumental in cathelicidin production to eliminate cryptic bacteria. 

In most cases of rosacea, the AID should be helpful.  Eliminating dietary sources of inflammation, especially vegetable oils (the source of omega-6 fatty acids that are converted into inflammatory prostaglandins), should reduce rosacea symptoms.

In advanced, severe cases, however, it appears that maintenance of the suppression of the response to cryptic bacteria is required to prevent endotoxin-based inflammation.  Thus, most treatments that decrease inflammation, e.g. omega-3 oils, vitamin D3, Vagal maneuvers, can paradoxically produce elevated inflammation.  These treatments may also inadvertantly contribute to inflammation by upsetting pathogenic interactions between bacteria and intestinal cells.  I have discussed these paradoxical ramifications in another article.

references:
Brinnel H, Friedel J, Caputa M, Cabanac M, Grosshans E.  1989.  Rosacea: disturbed defense against brain overheating.  Arch Dermatol Res. 281(1):66-72.
Walters RW, Shukla AK, Kovacs JJ, Violin JD, DeWire SM, Lam CM, Chen JR, Muehlbauer MJ, Whalen EJ, Lefkowitz RJ.  2009.  Beta-Arrestin1 mediates nicotinic acid-induced flushing, but not its antilipolytic effect, in mice.  J Clin Invest. 119(5):1312-21.

Vagus Nerve Controls Gut Inflammation II

Inflammatory Mast Cells Silenced

In a previous article, I outlined the role of the vagus nerve in responding to infection/damage signals by producing signals that inhibit inflammation. In a recent article (ref. below), the role of the vagus nerve in gut inflammation was examined using real-time biophotonic labeling. Basically that means that a video camera sensitive to infrared can be used to detect infrared dyes produced when NFkB is activated -- the camera is able to visualize regions of inflammation in living mice. Using this technique, researchers were able to demonstrate that cutting the vagus nerve produced heightened inflammation in gut treated with an irritant. The vagus nerve appears to stimulate regulatory T cells that lower the activity of inflammatory cells.

Inflammation/NFkB Activation Visualized in Live Mice

The studies were performed in a mouse line constructed to express an infrared fluorescent protein in cells in which the inflammation transcription factor, NFkB, is activated. Mice of this strain were prepared with and without the vagus nerve intact leading to the intestines. The mice were then exposed to sodium dextran sulfate (DSS) to simulate inflammatory bowel disease symptoms.

Cutting the Vagus Nerve Permits Inflammation

Mice with intact vagus nerves exhibited much less inflammation in their gut than those without vagus innervation. The cut vagus experiments demonstrated that the vagus nerve was responsible for suppressing inflammation. Further experiments were performed to determine if the inflammatory and anti-inflammatory reactions could be transferred to other mice by transferring cells from the treated mice.

Regulatory T Cells (CD4+, CD25+) Block Inflammation

Transfer experiments showed that inflammatory T cells (CD4+, CD25-) from cut vagus, DSS mice would cause bowel inflammation in other mice, but that did not happen with the same type of cells from mice with intact vagus nerves. Further tests showed that either cutting the vagus or adding inflammatory T cells from a mouse with a cut vagus, reduced the population of regulatory T cells (CD4+, CD25+) in control mice treated with DSS. So, without the vagus stimulation, the regulatory T cell population declined in the presence of inflammatory signals.

Absence of Regulatory T Cells Can Explain Many Inflammatory Diseases

In many inflammatory diseases, e.g. celiac, Crohn’s disease, rosacea, there appears to be a deficiency of regulatory T cells. In the absence regulatory T cells, signals from vagus nerves will no longer produce anti-inflammatory suppression. In fact the same nerve signals may become inflammatory. This would explain why rosaceans will become inflamed by hot or cold stimulation that would normally lead to anti-inflammatory stimulation of regulatory T cells. Similarly, capsaicin, castor oil and menthol, which normally produce an anti-inflammatory response, produce inflammation in rosaceans.

[Vagal stimulation exercise links:  here and here.]

reference:
O'Mahony C, van der Kleij HP, Bienenstock J, Shanahan F, O'Mahony L. 2009. Loss of vagal anti-inflammatory effect - in vivo visualization and adoptive transfer. Am J Physiol Regul Integr Comp Physiol. Aug 12. [Epub ahead of print]

Cure for Inflammatory Diseases

Destabilizing Gut Biofilms by Simple Remedies

The intercommunication between the gut flora biofilms, the cells of the immune system juxtaposed with the intestinal endothelium and cryptic bacteria/tissue biofilms produces stable chronic inflammatory disease. Disrupting the gut biofilms may permit a resumption of effective immunity and remission.

Disrupting Biofilms to Treat ASDs

Cristian Stremiz brought to my attention the work of Dr. Anju Usman on the treatment of autism spectrum diseases by attacking inflammatory gut biofilms.

A Panacea

This approach, based on the use of common food components, to attack the gut biofilm matrix of acid polysaccharides, cations and proteins, should be generalizable to most inflammatory diseases. The interventions also provide facile explanations for the utility of numerous traditional cures such as vinegar, fiber, glucosamine, pectin, whey, proteases and probiotics.

Cures Act via Gut Flora Biofilms

There are numerous anecdotal reports of traditional, simple remedies working for essentially all diseases. Tantalizingly, many of these diseases are also occasionally successfully treated with antibiotics. The common thread seems to be the involvement of inflammatory gut flora and perhaps cryptic bacteria residing in the tissues displaying symptoms. Glucosamine works sometimes for arthritis, but little of the glucosamine that is eaten reaches the blood stream and the aching joints that seem to become less inflamed. Vinegar, pectin, and fiber have also been attributed with curative powers, yet none is likely to impact inflamed joints directly. Impacting gut biofilms is much easier to explain.

Biofilms of Bacteria Attached to Acidic Polysaccharides and Divalent Cations

Acidic polysaccharides are produced by bacteria and divalent cations cross-link the polysaccharides into a matrix. The bacteria have agglutinins to attach to the matrix. Gut pathogens produce agglutinins that they use to attach to the heparan sulfate (HS), the predominant acid polysaccharide of the intestinal epithelium. Mast cells of the intestines normally release heparin, which is a mixture of HS fragments, to stick to the agglutinins and block attachment to the HS of the epithelium. Numerous bacterial species form complex communities on the polysaccharide matrix and prevent access by antibiotics. Biofilms require 100X the antibiotic concentrations and a cocktail of different antibiotics to eradicate the bacteria.

Biofilms Disrupted by Competing Acid Polysaccharide Fragments and Cation Chelators

The Achille’s heal of biofilms is the ionic interaction between the acidic polysaccharide and divalent cations. This interaction can be attacked by both small fragments of similar acid oligosaccharides, by organic acids that can solubilize the cations, e.g. acidic acid in vinegar, or by chelators, such as EDTA. All of these treatments can remove the calcium, magnesium and iron that is essential to the matrix. Small molecules, such as glucosamine, chondroitin sulfate fragments, heparin, and pectin, can disrupt biofilms. Molecules that bind to heparin or nucleic acids, e.g. berberine, quinine (tonic), methylene blue, should also be effective in disrupting biofilms. [Note that the similarity between amyloid production and biofilms, means that treatments should overlap.] Lactoferrin is effective, since it both binds iron and binds to acidic polysaccharides via its heparin-binding domains.

Proteases Cleave Agglutinins

Stomach proteases, e.g. pepsin, specifically cleave proteins to release heparin-binding, acidic polysaccharide-binding domains that inhibit biofilm production in the stomach. Subsequently, the basic, antimicrobial peptides and agglutinins are cleaved by proteases, e.g. trypsin, that hydrolyze the binding domains. Eating proteases, such as nattokinase present in fermented soybeans, dissolves intestinal biofilms by attacking the agglutinins. The pathogenic E. coli and avian H5N1 also have these agglutinins. It is, therefore, wise to avoid establishing gut biofilms that can immobilize pathogens.

Probiotics Protect Against Biofilms

Resident gut bacteria that produce organic acids, e.g. lactic acid or acetic acid, provide protection against biofilm formation. Examples are the bacteria present in common forms of fermentation and food preservation, e.g. Lactobacillus sp., and the bacterium present in exclusively breastfed babies, Bifidobacter sp. Formula fed babies rapidly develop inflammatory biofilms, which explains their high rates of intestinal and respiratory diseases, as well as increased rates of inflammatory diseases.

Biofilm Inflammation Results in Inflammatory Bowel Disease, etc.

Gut biofilms support system-wide chronic inflammation that leads to allergies, autoimmune diseases, degenerative diseases and probably cancers. This attach on the gut also produces a leaky gut that supplies the bacteria that a moved by macrophages of the gut to all parts of the body. This may be how Chlamydia pneumoniae colonizes sites of inflammation throughout the body.

Attacking Gut Biofilms Is the First Step in the Treatment of All Inflammatory Diseases

Many inflammtory diseases, e.g. chronic lyme disease, rosacea, may be refractory to treatment with antibiotics, because of the reservoir of bacteria in gut biofilms. Attacks on gut biofilms with relatively non-intrusive treatments, such as vinegar, EDTA, lactoferrin and proteases, may lower the total resident pathogen load and make subsequent antibiotic treatment more effective.