Health and Heparan Sulfate Circulation — Connective Tissue is Alive

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Arthritis, Alzheimer’s, diabetes, cardiovascular disease, osteoporosis, cancer, etc. are all diseases of cellular metabolism and secretion.  What goes on inside cells and on their surfaces explains a lot about health and why we get sick.  Cells feed off of what’s around them, use some of those materials to replicate and package up cell-made materials for export.  Eat, replicate and secrete.  Symptoms of disease result if those processes are compromised.

Cell that make Cartilage, Eat Cartilage

The connective tissue that makes up the cartilage of tendons and the non-mineral parts of bones, as well as a layers of skin, is made up of proteins (collagen) and polysaccharides (glycosaminoglycans, GAGs), e.g. heparan sulfate, hyaluronan and chondroitin sulfate, produced by  chondrocytes or fibroblasts.  These proteins and polysaccharides are synthesized and then secreted by cells.  This process goes on continuously, since the connective tissue is alive and literally crawling with cells that make the cartilage.  To keep the connective tissue healthy, the old tissue has to be digested, so that new material can replace it.  Thus, the cells that live in cartilage also eat cartilage.  These cells get all of their nutrients, e.g. protein and carbs, from eating cartilage.  They don’t get glucose and amino acids, or even oxygen (they ferment), from the blood, because there are no blood vessels in cartilage.  The photomicrograph at left shows the red chondrocytes surrounded by a light capsule of heparan sulfate as they burrow through the purple cartilage.  The next micrograph shows the cytoskeleton of actin filaments (stained with a red fluorescent dye, that lies under the cytoplasm of a chondrocyte.  Motor proteins move other proteins, such as syndecans, the proteins to which the heparan sulfate chains are attached, through the  cell membrane (see the animations below.)  The last micrograph shows the green stained microtubule network on which vesicles move to carry heparan sulfate products from one end of the cell to the other (under the actin and past the orange-dyed nucleus) during synthesis and digestion.

Chondrocytes Burrow Through Cartilage

Chondrocytes are the cells that eat and make cartilage, but all of this eating and making goes on at the same time that the cartilage is also holding everything together, i.e. it is still strong.  If cartilage is cut and the cut ends are held tightly together, the chondrocytes will knit the cartilage together and it will become as strong as it was. 

Heparan Sulfate Circulates over the Surface of Cells

Chondrocytes are not actually rigidly embedded in the cartilage, but rather maintain a capsule of heparan sulfate around themselves.  Thus, they continue to secrete a mixture of heparan sulfate, chondroitin sulfate and collagen, but the heparan sulfate is recycled through the capsule and the other molecules merge into the existing cartilage.  Thus, the heparan sulfate is a kind of carrier that keeps the cartilage from “setting up” while it is being made and transported.  Other cells of the body, such as neurons, don’t make cartilage, but they still have heparan sulfate (HS) circulation that is intimately involved in many other processes, such as the action of hormones.  Disruption of HS circulation causes the symptoms of Alzheimer’s or type 1 diabetes, for example, since amyloids assemble as filaments on threads of HS, and the amyloid filaments jam essential HS circulation.  Plaque in atherosclerotic vessels is high in HS content.  HS is also a major component surrounding vessels to form the blood brain barrier and the barrier to protein loss from kidneys into urine or loss into the gut lumin.  Heparin (fragments of HS) is continually released from mast cells in the lining of the gut to prevent pathogens from binding to cell HSPGs. 

HS Sweep the Cell Surface

There is a constant flow of heparan sulfate proteoglycans (HSPGs) through the cell membrane from the rear of the chondrocyte to the front where the HS is digested again and the protein that was embedded in the membrane, syndecan, is recycled to the Golgi for another trip.  HSPGs (animation to left with blue protein and yellow HS) are attached to motor proteins that propel them through the membrane along microfilaments of actin that form the cyctoskeleton just under the membrane in the cortical region of the cell.  Thus, the heparan sulfate of the HSPGs stick out like hair from the cell surface and sweep continuously from the back to the front of the cell.  At the front of the cell, the HS sweeps through the intact cartilage and reverses the process of cartilage assembly.  The chondroitin sulfate, collagen and HSPGs are dragged into the cell and digested.  The protein parts of the HSPGs are transported to the Golgi  and the HS is synthesized along with other cartilage components and moved in vesicles along microtubules before it is secreted.

HS is Secreted at One End and Eaten at the Other

The animation left shows 1) the initial digestion of the cartilage proteins and polysaccharides on the left.  These cartilage components of amino acids and sugars, are used by the chondrocytes as their sole nutrients 2), and to produce new proteoglycans 3) HS and chondroitin sulfate proteoglycans, in the Golgi, are 4) packaged into secretory vesicles and are 5) secreted on the right.  The HS chains, attached to proteins, are 6) swept through the membrane (see the first animation above) toward the front of the cell, leaving the collagen and chondroitin sulfate for form cartilage behind.  In the process, the heparan sulfate proteoglycans 7) disrupt and solublilize old cartilage ahead as the chondrocytes 8) move through the connective tissue like moles digging through soil.

Other Cell Processes Involving Heparan Sulfate:

• Amyloids of Alzheimer’s and type I diabetes assemble bound to HS.
• Hormones bind to receptors wrapped around HS.
• Blood clotting is controlled by HS.
• Complement is controlled by HS.
• Blood brain barrier is composed of HS.
• Kidney protein barrier is composed of HS.
• Inflammation blocks HS synthesis and promotes heparanase synthesis.
• GAGs are animal soluble fiber when eaten and feed gut flora.
• Pathogens bind to HS.
• HIV-TAT is transported between cells by HS circulation.
• Heparin is made by heparanase fragmentation of HSPG in mast cells and is secreted along with histamine. 
• NFkB activation inhibits HSPG production and stimulates heparanase production.
• Heparan sulfate proteoglycans organize nerve synapses and acetylcholine esterase binds to HS. 
• Gastric proteases cleave around heparin binding domains of proteins, e.g. milk, consist of clusters of basic amino acids.  Peptides with heparin binding domain are antimicrobial; all of the heparin binding peptides are subsequently degraded by pancreatic proteases.
• Heparanase is initially secreted inactive and bound to HSPGs, but it remains bound and is internalized again along with the recycling HSPGs, and is activated before being secreted again.
• Allergens and autoantigens are unusual proteins with sequences of three adjacent basic amino acids (arginine or lysine) that require HSPG circulation for presentation of the immune system.  Nuclear proteins that interact with nucleic acids have sequences of four basic amino acids, the nuclear translocation signal, and are therefore common antinuclear auto antigens.

Health Diagrams

Transglutaminase, Gluten, Celiac, Inflammation, Autoimmunity

The point of this post is that the intestines produce an enzyme, transglutaminase (TG) that normally protects the gut from toxic plant proteins, such as grain gluten, but modern food processing and antibiotics corrupt digestion of gluten to produce intestinal inflammation and a series of related autoimmune diseases including celiac, thyroiditis, diabetes, baldness and atherosclerosis. 

Transglutaminase Links Proteins Enzymatically

Transglutaminase is a ubiquitous enzyme produced in the intestines, thyroid, heart, skin, hair follicles, etc.  This enzyme attaches to a protein (TG + ProA ~~> TG-ProA) via amino groups extending from some of the protein's amino acids, e.g. lysine or glutamine, and then the enzyme replaces itself by another protein leaving the two proteins crosslinked (TG-ProA + ProB ~~> TG + ProA-ProB).  Another alternative reaction is to leave the original glutamine without its amino group to yield glutamic acid residues.

Linking Proteins Makes Connective Tissue Tough

Transglutaminase is useful to crosslink the proteins in connective tissue.  Proteins in basement membranes form a matrix by binding to the heparan sulfate sidechains of another basement protein, perlecan.  The heparin-binding domains consist of basic amino acids that TG can react with to crosslink the proteins.

Linking Pathogen Proteins

Transglutaminase is also produced to crosslink the DNA/heparin/matrix polysaccharide-binding domains of pathogenic bacteria leading to aggregation, localization and death of the bacteria.  Inflammation resulting from activation of the inflammatory transcription factor, NFkB, stimulates production of TG.

Gluten is a Plant's Way of Saying "Don't Eat Me!"

Gliadin is a protein component of gluten that contains long stretches of glutamine residues, i.e. it is a polyglutamine protein similar to the protein that causes Huntington's disease.  Gliadin is an advantage as a storage protein for grain, because it is aggregated by the TG that protects the lining of the intestines of herbivores, such as humans, makes the animal sick and thereby discourages eating the grain.  Aggregation of gliadin/gluten inhibits digestion of the grain protein and can leave TG bound to gliadin.  Conversion of the polyglutamine stretches to polyglutamic acid stretches that are negatively charged, produces proteins that will bind to the positively charged heparan sulfates that circulate along the surface of intestinal cells leading to damage and inflammation.

Basic Triplet Leads to Antibody Production

Transglutaminase is also transported into cells, because it contains a region with a triplet of basic amino acids (...EPKQKRKLVA...).  This internalization probably contributes to enhanced presentation of TG to the immune system for subsequent antibody production.

Transglutaminase is Inflammatory

Transglutaminase interaction on the surface of cells also activates, NFkB, the transcription factor responsible for inflammation. Thus, TG turns on inflammation and part of inflammation is the activation of the innate immune system that includes production of TG.  This circular activation may produce autoinflammation that is associated with various forms of inflammatory bowel diseases.

Gluten Sensitivity is Normally Controlled By Gut Flora

Gluten sensitivity expressed by most people, is the intestinal response to the toxicity of gluten as it interacts with TG and causes inflammation.  This inflammation will also result in immune presentation of both gliadin and TG, and production of antibodies to both. Antibody production will normally be controlled by regulatory T cells of the immune system, unless spreading inflammation in the gut and/or antibiotics destabilizes the gut flora and compromises regulatory T cell development in the intestines.  

Anti-Glutaminase Antibodies Attack the Gut

Celiac results from uncontrolled production of antibodies to gliadin and TG with attack by the immune system on the aggregated gliadin/TG on the surface of the intestinal epithelium.  Celiac flare ups in response to eating even small quantities of gluten lead to further inflammation of the gut and further disruption and simplification of gut flora.

Celiac Leads to Thyroiditis and Much More

Transglutaminase is also produced by the thyroid and celiac will develop into a more generalized autoimmune disease that results in Hashimoto's thyroiditis.   TG production in the skin can result in skin rashes and may contribute to rosacea.  The base of hair follicles contains TG involved in hair production, and may contribute to some forms of hair loss.  Another substantial worry about the sequelae of celiac and gluten intolerance is the presence of TG in coronary arteries.

Antibiotics are Part of the Gluten Problem

Celiac and gluten sensitivity seem to be increasing with modern processing of grains and increased use of antibiotics.  Wheat has been gradually changed by traditional breeding, but genetic engineering has not yet been developed for wheat.  So, at least in this case, GM wheat cannot be part of the problem.  Many recent studies show that antibiotics profoundly and permanently alter gut flora.  As a result, the immune system, which is dependent on gut flora diversity is compromised, and various forms of autoimmunity and allergies develop.

Super Fine Flour Damages Gut Flora

Germ and bran are removed from all wheat before it is ground.  This is true even for whole grain flours, which have some of the germ and bran added back after milling.  Modern milling may be part of the gluten problem, because the flour is ground so fine that the grains of starch are broken.  Broken starch grains are digested by pancreatic amylases in the upper intestines, whereas some of the starch from intact grains is digested by gut flora in the colon.  Thus, modern wheat flour fails to feed gut flora like soluble fiber to produce short chain fatty acids, e.g. proprionic acid that supports Treg development; modern superfine flour supports autoimmune diseases and allergies.

Cultural Practices Make Gluten Safe

Wheat has been bred to produce bread as fast as possible from superfine flour.  This rapid bread production eliminates the exposure of gluten to enzymes from both germinating wheat seed and fermenting bacteria, which are part of traditional bread making.  Coarsely milled, traditional flour responds to soaking in water by activating enzymes that partially digest gluten, since gluten is a storage form of amino acids destined for the seedling.  Sour dough starter, a mixture of bacteria that can ferment the starch and gluten into short chain fatty acids and bubbles of carbon dioxide, has been used traditionally to provide leavening and flavor to bread.  Both flour and bacterial enzymes modify the structure of gluten to render it less toxic to the intestines.  Cultural traditions insured that gluten would be systematically detoxified by enzymes during hydration and fermentation of dough prior to baking.  Modern processing leaves wheat gluten in bread unmodified and toxic.

Prevention and Cure:  Eliminate or Detoxify Wheat and Add Bacteria

Preventing and curing diseases associated with gluten and transglutaminase is simple.  Eliminating wheat would do the trick.  Unfortunately, wheat is the mainstay in many parts of the world.  Fortunately, gluten intolerance is not uniformly observed where wheat is eaten.  This indicates that there are potentially safe ways to eat wheat and bread.  I gained insight into how to eat wheat safely from two books that were recently published:  Cooked by Michael Pollan and Artisan Bread in Five Minutes a Day by Jeff Hertzberg, MD and Zoë François.

Michael Pollan has recently become interested in gut flora and his book revealed how he built up a healthy gut flora eating homemade fermented food and compromised his work with antibiotics.  The major breakthrough that I made by reading Cooked was based on his experiments in baking whole wheat bread.  He hydrated the flour first and then used sour dough starter for lengthy fermentation.  This was the same process that I had used to make great loaves of bread (photo above) using Jeff Hertzberg’s directions in Artizan Bread in Five Minutes a Day.

The answer to gluten intolerance and most autoimmune diseases amounts to eliminating wheat or treating wheat in a safe, traditional process that inactivates the toxic properties of gluten; and maintaining a healthy gut flora (probiotics are not enough) with hundreds of different species of bacteria that promote the development of the suppressive immune system mediated by regulatory T cells:

Safe Traditional Bread 

• Remove bran and discard as toxic insoluble fiber.
• Grind wheat to retain starch grain structure.
• Soak flour to hydrate and activate wheat enzymes to start digestion/detox of gluten.
• Ferment dough with bacteria (sour dough starter) to continue digestion/detox of gluten.
• Bake.

Develop Healthy Gut Flora and Suppressive Immune System

• Avoid antibiotics that kill bacteria.
• Avoid hygiene practices, e.g. antibacterial soaps, bleaching surfaces, closing toilet covers, etc. that eliminate sources of healthy bacteria.
• Kiss your loved ones and pets, and encourage everyone to garden/play in the soil (an excellent source of thousands of different species of bacteria.)
• Recruit healthy gut bacteria by eating a variety of homemade fermented vegetables. My most highly recommended source is my friends at: http://www.fermentista.us
• Remember that cooked or pasteurized foods do not contain useful bacteria.
• Remember that dairy probiotic bacteria cannot live in the human gut and can only provide a temporary help to the immune system.
• Limit the variety of foods that are consumed and gradually change with the seasons to avoid rapid changes in nutrients to which gut flora cannot adapt.  Food intolerances indicate maladapted gut flora.
• Constipation indicates dysfunctional gut flora and a compromised immune system.

Allergy, Asthma, Autoimmunity Start the Same Way

Inflammation is the current medical buzzword. Name the disease and inflammation is there.

Reproduction Requires Controlled Inflammation
Aspirin blocks many of the steps in triggering inflammation and thus, aspirin administration can be used to reveal a role of inflammation in many unexpected places. Aspirin is effective in blocking some forms of infertility, inhibiting miscarriages and ameliorating postpartum depression. So inflammation is a critical part of reproduction. But, also notice that depression is a symptom of chronic inflammation.

Cancer Requires Inflammation
High dose (IV) aspirin has been successfully used to treat cancer. Inflammation is required for cancer growth, because both use the same transcription factor, NFkB. The aberrant signaling of cancer cells would normally lead to programed cell death, apoptosis, but inflammation blocks apoptosis. Aspirin can in turn block NFkB and in the absence of inflammation, cancer cells die by apoptosis.

Inflammation is Self-Limiting
Aspirin also transforms the COX/lipoxidase system to produce anti-inflammatory prostaglandins/eicosinoids. Inflammation normally progresses into anti-inflammation. Blocking this progression leads to chronic inflammation and a shift from local to systemic inflammation with the rise of inflammatory interleukins in the blood stream.

Immune Response Requires Inflammation
The signal molecules (IL-1, IL-6, TNF) and transcription factor, NFkB, associated with inflammation were all initially identified in the development of lymphocytes. Hence, IL stands for interleukin, a hormone that triggers leukocyte (literally white blood cells or cells associated with the lymphatic immune system, i.e. lymphocytes) development. The nuclear factor, i.e. transcription factor, involved in expression of the large chain, kappa, of immunoglobulins in B cells, was called NFkB.

Genes Expressed by NFkB Cause Symptoms of Inflammation
About five dozen genes are under control of NFkB. Among these are COX-2, the enzyme that converts omega-6 arachidonic acid to inflammatory prostaglandins; iNOS, the enzyme that produces nitric oxide that dilates blood vessels to produce hot, red skin; and the inflammatory interleukins, IL-1, IL-6 and TNF, associated with autoimmune disease, fatigue and cachexia (wasting).

Autoimmunity and Allergy Start with Inflammation
Medical treatments focus on symptom abatement and ignore cause. What causes obesity, allergy or autoimmune disease? The answer appears to be chronic systemic inflammation plus exposure to unusual proteins. The unusual proteins are immunogenic, i.e. interact with the immune system to produce antibodies or reactive T-cell receptors, and are subsequently recognized as autoantigens or allergens, that are the targets for immune attack. Inspection of these autoantigens and allergens shows that they all have one thing in common, they bind to heparin via a strong heparin-binding protein domain that is typically a triplet of adjacent basic amino acids.

Heparin is a Short, Highly Sulfated Fragment of Heparan Sulfate
Commercial heparin is purified from the intestines of hogs and cattle. Heparin is released from mast cells (made fluorescent for microscopy using berberine) along with histamine and is released into the intestines to block pathogens from binding to the heparan sulfate that is part of the intestine surface. The heparin is anti-inflammatory and it contributes to minimizing the inflammatory response of the intestines to food.

Inflammation Reduces Heparan Sulfate Production
Pathogen-generated inflammation of the intestines reduces heparan sulfate production and increases immune response to food antigens. NFkB activation by inflammation turns off the production of some genes needed for heparan sulfate proteoglycan (HSPG) synthesis. Since HSPG is a major component of the basement membrane that holds tissues together, the reduction of HSPG results in protein loss (proteinuria) from kidneys, leaking of intestines, and disruption of the blood/brain barrier.

Reduction of HSPG Results in Immunological Presentation of Autoantigens/Allergens
Proteins are brought into cells by specific binding to protein receptors. In many cases, particularly involving signaling or growth factors, both the signal molecules and the receptors bind to heparin. In addition, there is a robust circulation of HSPG, which is secreted and internalized with a half-life of approximately six hours. The sweep of the HSPGs take heparin-binding proteins with them for internalization, e.g. HIV-TAT, heparanase, tissue transglutaminase. I think that this HSPG sweep under inflammatory conditions also internalizes basic autoantigens and allergens with strong heparin-binding domains. This internalization is the first step toward immunological presentation and the immune response to autoantigens and allergens.

Autoantigen/autoantibody/HSPG Complexes Kill Cells
Antibodies against self-antigens, autoantigens form antigen/antibody complexes that also bind to and cross-link HSPGs, because of the heparin-binding domains of the autoantigens. The large complexes may disrupt HSPG circulation and trigger apoptosis or abnormal physiology. There are many other examples of heparin-based complexes that are toxic, e.g. Alzheimer’s amyloid plaque, diabetic beta cell antibody complexes, celiac gluten/tRG antibody complexes, multiple sclerosis myelin antibody complexes, atherosclerotic plaque.

Anti-Inflammatory Diet and Lifestyle Protects
Dietary and lifestyle adjustments that minimize inflammation, e.g. low starch, no HFCS, low vegetable oil (except olive) and supplements of vitamins D & C, fish oil (omega-3) and glucosamine, reduce the risk of allergies/asthma, degenerative diseases and cancers. Simple, high level supplements with fish oil reduce numerous mental disorders, e.g. depression, ADHD; infertility, pre-eclampsia and postpartum depression; allergies, asthma; arthritis, atherosclerosis; burn recovery, septicemia and head injury.

Reducing Inflammation is a Panacea for Modern Diseases
Most modern diseases have an inflammatory component, because modern diets are rich in inflammatory components, e.g. starch/sugar, corn/soy oil, HFCS, trans fats, and exercise is minimal. The medical industry has not successfully promoted healthy eating and exercise; and in fact has promoted the devastating replacement of saturated fats with inflammatory polyunsaturated vegetable oils. Meat production has moved away from grazing on omega-3-rich plant vegetation to omega-6-rich corn and soy. Replacement of the corn/soy based agricultural economy would have predictably immense beneficial impact in reducing inflammation-based degenerative autoimmune diseases and cancers.

Inflammation Causes Disease

Human diets have changed dramatically over the last few hundred years, and as a consequence so have our diseases. The most recent shift in diet over the last hundred years has resulted in a shift from infectious diseases to degenerative diseases. This trend is summarized in the following Wikipedia entry.

Lifestyle diseases, from Wikipedia:

"Lifestyle diseases (also called diseases of longevity or diseases of civilization) are diseases that appear to increase in frequency as countries become more industrialized and people live longer. They include Alzheimer's disease, atherosclerosis, asthma, cancer, chronic liver disease or cirrhosis, Chronic Obstructive Pulmonary Disease, Type 2 diabetes, heart disease, nephritis or chronic renal failure, osteoporosis, acne, stroke, depression and obesity.

Death statistics in the United States
In 1900, the top three causes of death in the United States were pneumonia/influenza, tuberculosis, and diarrhea/enteritis. Communicable diseases accounted for about 60 percent of all deaths. In 1900, heart disease and cancer were ranked number four and eight respectively. Since the 1940s, the majority of deaths in the United States have resulted from heart disease, cancer, and other degenerative diseases. And, by the late 1990s, degenerative diseases accounted for more than 60 percent of all deaths.
Reference:
National Center for Health Statistics, National Office of Vital Statistics, 1947 for the year 1900 (page 67), for the year 1938 (page 55)."

My point here is that all of the so-called lifestyle diseases are also based on inflammation. I checked the research literature for studies of the response of each of these diseases to diets supplemented with omega-3 fish oils. Studies had been performed in each case. Reduction of inflammation by fish oil treatment was uniformly effective in reducing symptoms of all of the degenerative diseases. Other diseases that can be added to the inflammatory list are spinal disc problems and hypertension. It is interesting that disc dislocations are associated with coeliac, an inflammatory/autoimmune disease. It is also interesting that acne and depression are listed. Acne is indirectly associated with diet, but if sufferers shift to an anti-inflammatory diet, acne symptoms disappear. Depression associated with childbirth is particularly responsive to anti-inflammatory drugs, diet and exercise. Most of the symptoms associated with aging are just due to inflammation and are similarly responsive to anti-inflammatory lifestyle changes

To summarize:

• Modern degenerative diseases are caused by modern inflammatory diets (and insufficient exercise.)
• Anti-inflammatory diet and lifestyle reduce degenerative diseases.
• Aging is predominantly mismanaged inflammation.
  

Statins and Atherosclerosis

A recent study (JUPITER) on the statin Crestor was ended prematurely when the drug was shown to dramatically reduce vascular events. The statin was tested on patients with chronic inflammation as judged by elevated C-reactive protein, but with low LDL. These patients would not normally be treated with statins and therefore represent an immense new market for statins.

Statins are supposed to act by interfering with the synthesis of cholesterol and thereby lowering the serum concentration of the lipid carrier LDL. Lowered LDL is supposed to decrease vascular disease that is aggravated by accumulation of cholesterol at sites of inflammation on the surface of blood vessels.

Unfortunately the data linking cholesterol production, LDL levels and vascular disease is weak. Thus, it is possible to lower LDL and have no impact on cardiovacular disease statistics. The recent study on Crestor was interpreted as being support for the link between LDL levels and vascular disease, but I think it shows something very different.

There is increasing evidence that vascular disease is based on diet-based chronic inflammation and that statins have a mild impact on reducing inflammation. It follows then that statins will reduce inflammation enough to have an impact on vascular disease, independent of effects on LDL levels. The Crestor study actually showed that patients with low levels of LDL but chronic inflammation benefited from lowering of inflammation. The LDL levels were unimportant. Reducing inflammation was the point and using statins to reduce inflammation is unnecessarily expensive and ineffective. Adjusting diet makes a lot more sense.

Drug companies are already pushing for increased use of statins on larger segments of the US population to provide prevention from atherosclerosis, stroke and heart disease. This would be immensely expensive with marginal returns. It is also just treating the symptoms without addressing the cause.

The solution to cardiovascular disease is dietary. Omega-6 oils and low availability of omega-3 fish oils is the major cause of the chronic inflammation that is the major risk factor for cardiovascular disease. The major US vegetable oils, corn, soybean, cottonseed, safflower, need to be drastically restricted and olive oil needs to be encouraged. We need to recognize that saturated fats are safer than the omega-6 polyunsaturated fats that have replaced them. Elimination of omega-6 vegetable oils and use of fish oil supplements are cheap and effective ways of lowering chronic inflammation.

Cardiovascular disease is also based on decreasing muscle mass, sarcopenia, which is also the basis for increasing chronic inflammation inappropriately attributed to aging. People get less physical exercise as couch potatoes or with decreasing activity as they age. The result is replacement of muscle by fat, and fat is inflammatory. Obesity is an extreme of this trend that leads to high chronic inflammation identified as metabolic syndrome, the prelude to a suite of nasty degenerative diseases: diabetes, atherosclerosis, allergies, cancer, Alzheimer’s, etc.

The obvious bottom line is to avoid all of these problems with an anti-inflammatory diet and lifestyle.

Palmitoleate: omega-7 lipokine

Palmitoleic acid is responsible for keeping people healthy (lipokine) and for the smell of old people (nonenal). Overproduction of this lipid by blocking uptake of fats results in resistance to type II diabetes and atherosclerosis.

If you listen to the commercials on television, you know that there are two sources of fats/cholesterol; you either make it in your cells or take from your diet. Recent research shows that mice that have been genetically modified to lack cytoplasmic lipid carriers, can’t store dietary fat, so they make more of their own lipids. Specifically, they make more palmitoleic acid (C16:1n7). By U.S. standards, those defective mice are very healthy. It turns out that palmitoleic acid acts as a lipid hormone that communicates between fat tissue and other organs, and maintains a healthy metabolic balance.

Lipids are hydrophobic and require protein carriers to be moved from their source, such as the intestines, through the blood and to be offloaded into tissues. Most of the lipids enter the diet as triglycerides, i.e. a three carbon glycerol with three fatty acids attached. Those fats are extracted from food with bile, which is a mixture of modified cholesterol salts that acts as a detergent to dissolve fats. The dissolved fats, in the form of chylomicrons (big fat droplets coated with a lipid layer and proteins) are produced by intestinal cells and released into the blood stream. During transit, a lipase removes the fatty acids from the triglycerides. As in all of the lipid transport systems, the protein carriers determine how the lipid contents are distributed.

If a fatty acid or triglyceride is added to a cell membrane, the lipid would get stuck in the membrane's double layer of phospholipids. Fat droplets in cells are nothing more than fats that are loaded into the membrane of a cellular vesicle until a droplet covered by a half membrane forms. The alternatives for lipid transport are the HDL and LDL (protein coated lipids of the blood), and the intracellular fatty acid-binding proteins. The proteins bound to the surface of LDLs and HDLs bind to receptors on cell surfaces and control transfer of lipids to and from cells. One example is apolipoprotein E4. This protein is intimately involved in determining risk for athersclerosis and Alzheimer’s. ApoE4 binds to its cell surface receptor via heparin. Note the blue basic amino acids that form a massive heparin-binding domain down one side of the protein.

Fatty acid-binding proteins (FABPs) are just globular proteins, with hydrophobic amino acids arranged in the center and hydrophilic, water-bonding, amino acids on the surface. I have drawn the structure of a FABP using a graphics program called Chimera to visualize X-ray crystallographic data in the National Center for Biomedical Information (NCBI) database. The continuous chain of amino acids is shown as a white ribbon and the surface of the protein is shown as a transparent overlay. The protein chain makes a cage with the hydrophobic parts of the protein pointing toward the center to make a hydrophobic-lined container for the trapped fatty acid (pink). The two ends of the protein vessel are held closed by interdigitation of tryptophans (yellow) and basic amino acids (arginine and lysine, dark and light blue). The FABP also has a nuclear translocation signal, a group of four basic amino acids and other concentrations of basic amino acids displayed linearly across the surface of the cage (not shown), that probably are involved in transport of the trapped fatty acid from the cell surface to the surface of the nuclear envelope, which is involved in phospholipid assembly.

Mice engineered to have the human ApoE4 gene develop atherosclerosis and type II diabetes. If the FABPs of the fat cells of these mutant mice have also been removed, then the mice are essentially normal. Removal of the FABPs blocks the uptake of dietary fatty acids and stimulates the production of endogenous lipids, including the omega-7 fatty acid palmitoleic acid. This fatty acid is a lipid hormone, lipokine that stimulates normal metabolism and provides protection against several inflammation-based diseases. Interestingly, palmitoleic acid accumulates abundantly in the skin of old people and is converted to nonenal that has the smell of old books.

Cao H, Gerhold K, Mayers JR, Wiest MM, Watkins SM, Hotamisligil GS. 2008. Identification of a lipokine, a lipid hormone linking adipose tissue to systemic metabolism.Cell. 134(6):933-44.