Anti-Inflammatory Diet

All health care starts with diet. My recommendations for a healthy diet are here:
Anti-Inflammatory Diet and Lifestyle.
There are over 190 articles on diet, inflammation and disease on this blog
(find topics using search [upper left] or index [lower right]), and
more articles by Prof. Ayers on Suite101 .

Friday, February 26, 2010

ABO Oligosaccharides, RBCs, VWF, Endothelial Cells, Megakaryocytes

Blood Group Antigens Are Synthesized in the Golgi by Glycosyl Transferases A or B

This is another rant about poor teaching and false text book information.  I have been trying to summarize some of the key points of genetics and cell biology that I think should shape the minds of young biologists.  To make my point, I want to outline where the common ABO blood group antigens are made and displayed.

ABO Antigens Are Oligosaccharides, Not Proteins

Red blood cells that are type A will clump together with antibodies that bind to A antigens.  At this point many instructors leap ahead and say that the expression of the A gene results in the production of the A protein, that is displayed on the surface of RBCs.  Wrong.  The antigens are carbohydrates, short chains of sugars called oligosaccharides, attached to a lipid embedded in the RBC membrane.

Glycosyl Transferases - Enzymes that Assemble ABO Oligosaccharides

Oligosaccharides are synthesized by adding one sugar at a time onto a growing chain.  Information-rich oligosaccharides, such as the ABO antigens, are made of several different sugars and are linked in a variety of ways to other sugars, so each sugar is added by a different enzyme.  The sugar-adding-enzymes are called glycosyl transferases.  Similar to other macromolecular polymerizations, e.g. protein and nucleic acid synthesis, the monomer sugars are first activated by bonding to a nucleotide phosphate (typically UDP) and the sugar is transferred from this activated intermediate to the growing sugar chain, in this case the H antigen. 

The glycosyl transferase coded by A allele transfers an N-acetylgalactosamine to the end of the H antigen oligosaccharide, whereas the glycosyl transferase coded by the B allele transfers a galactose residue.

Dominance Means Functional Enzyme, Recessive Means Dysfunctional

The ABO blood group system provides a simple molecular interpretation of genetic dominance.  An allele is dominant if it produces a functional enzyme that gives the phenotype, in this case a particular glycolipid attached to an RBC.  A or B alleles that have mutated to yield dysfunctional proteins that no longer function as glycosyl transferases are recessive.  Recessive alleles don’t impact phenotype.  O antigen is nothing more than the original unmodified H oligossacharide.

ABO Is Bizarre because A and B Code for Two Alternative Functional Enzymes - Codominance

Multiple mutations converted an allele that coded for a glycosyl transferse into a second allele that transferred a different sugar.  A and B alleles code for two different glycosyl transferases that transfer two different sugars.  The result is codominance.  AB individual have both enzymes and produce both A and B antigens on their RBCs.  This is very unusual and inconsistent with Mendelian genetics.

AB Glycosyl Transferases Are in the Golgi to Produce Oligosaccharides for Export

Part of the peculiarity of the ABO system derives from the action of the A and B glycosyl transferases in the Golgi.  Proteins destined for secretion have a hydrophobic group of amino acids, the signal peptide, that is synthesized first as a messenger RNA is translated into protein on a ribosome.  The signal peptide orchestrates binding of the ribosome to the endoplasmic reticulum (ER) and the growing polypeptide is extruded into the ER.  A series of vesicle budding and fusing events transfers proteins to the lamina of the Golgi apparatus and a final fusion event with the cytoplasmic membrane results in secretion.

Specific enzymes retained in the ER and the Golgi recognize particular amino acid sequences and attach sugars to exposed hydroxyl of amino groups (O or N glycosylations).  The ABO antigens are a little unusual in that the oligosaccharide is attached to a lipid anchor, so that the A and B glycosyl transferases localized in the Golgi attach terminal sugars and the glycolipid remains bound to the cytoplasmic membrane and is displayed on the surface of the RBC.

RBCs Don’t Have Nuclei, ER or Golgi, but Normoblasts Do

Mammalian RBC’s don’t have nuclei, because the nuclei were expelled during RBC development.  Since the ER is an extension of the outer membrane of the nucleus and the Golgi is derived from the ER, it follows that RBCs don’t have any of these structures.  RBCs are just collapsed bags of ribosomes, hemoglobin mRNA, cytoplasmic enzymes, a few mitochondria, lots of hemoglobin and stiffened membranes displaying ABO oligosaccharide antigens.  The ABO antigens were assembled and displayed on the membrane before the loss of the nucleus.

ABO Antigens Are Also on von Willebrand Factor of Endothelial Cells and Platelets

I have never heard a good explanation of why a transfusion from a universal, type O donor to recipients with type A, B or AB blood doesn’t cause clumping of RBCs.  The galactose and galactosamine sugars that decorate B and A RBCs also commonly decorate the surfaces of bacteria.  The immune system is prevented from making antibodies against its own antigens and so it only produces antibodies against A or B antigens found in bacteria, if they are not own self RBCs.  Type O individuals lack A and B antigens of their own, so they produce anti-A and Anti-B against bacterial oligosaccharides.  So why don’t the anti-A and anti-B antibodies in type O blood serum clump type A or type B blood?

The answer is that a serum protein, von Willebrand Factor (vWF) is also decorated with the ABO oligosaccharides.  A type A person has type A vWF and a type B person has type A vWF.  Thus, the antibodies against A and B oligosaccharide antigens that are present in type O blood will be inactivated by binding to the A or B oligosaccharides of the recipients vWF.

vWF is synthesized by endothelial cells that line veins and arteries.  It is present in the secretory Weibel-Palade bodies of endothelial cells.  It is also present for secretion by platelets.

So, the ABO blood group antigens are very strange examples that are not protein, not Mendelian and are not even predominantly found on RBCs.  The AB oligosaccharides do provide good examples of the use of activated intermediates in macromolecular synthesis, the origin of organelles, secretion, erythropoiesis and immunology.

Tuesday, February 16, 2010

Last Week of the Eades Cure

Week 6 of The 6 Week Cure for the Middle-Aged Middle

It feels like I have established a new set point ten pounds lower than my start.  I dropped ten pounds easily in the first two weeks and then bounced around plus or minus two pounds for the next month.  The Cure is simple and effective.

The First Weeks of The Cure

The 6 Week Cure for the Middle-Aged Middle was written by Drs. Mary Dan and Michael Eades to efficiently lose abdominal visceral fat and tone the abs.  It starts with two weeks of three whey protein/cream/leucine shakes and one high fat/protein-low carb veggie meal per day.  This surprisingly tolerable regime (without all but essential medications, no alcohol and no grains) helps to reduce fatty liver and use up visceral fat around the abdominal organs.  I noticed the impact immediately and lost about a pound a day.  This also eliminated hunger and exposed snacking habits.

The Middle Weeks of The Cure

The second two weeks of The Cure permits occasional alcoholic beverages and three low carb meals per day, but without dairy.  That is basically meat/fish/eggs and low carb veggies for each meal.  Most calories were from fat rather than carbs.  Portion control became a new issue, but hunger was still not a problem.  The meals were very satisfying.  Energy for exercise returned, but weight loss ebbed.  It was harder to stay away from old snacking habits, since meals were back to a more normal pattern.

The Last Weeks of The Cure

During the last weeks of The Cure there is a final turn to what may be for some a new, low carb, higher fat eating style.  I chose The Cure, because I already knew that the eating philosophy of the Drs. Eades was consistent with my own anti-inflammatory diet and lifestyle.  I did not expect to be surprised by The Cure, but I was.  I learned a lot about my own eating habits.

Gut Flora Matter

I started The Cure, because I thought that the progression of dietary components would destabilize my gut flora and simultaneously destabilize my weight set point.  I anticipated that my gut flora would reorient, and they did.  There were all kinds of changes and some of the weight loss and gain was probably elimination of a pound of gut flora and reestablishment of a new bacterial order.  The new order also came with a lower body weight.

Hunger Comes with Carbs

For the first month of the diet, I was only hungry if I went longer than six hours without eating or if I slipped on the diet and introduced some extra carbs.  Straight protein early in the morning can cause an insulin rise and a blood sugar dip that leads to a little hypoglycemia, but it produces dullness, rather than hunger.  The only problem with the easy weight loss first two weeks, was that there was less energy with the protein shakes.

BMs Are Bacterial Motivated

The noticeable changes in bowel movements during The Cure, should have been expected, but they forced me to contemplate stools.  When I first realized the absurdity of eating breakfast cereals, because of their high carb/grain content, I went in search of alternative day-starters in other cultures.  At that time, I was still hesitant to embrace saturated fats, so I ran across salsas and stewed tomatoes.  The addition of stewed tomatoes to my breakfast (usually stewed tomatoes on a poached egg) made my gut happy and regular. 

The point in this context, is that my studies of BMs and constipation brought pectin to my attention again.  I had previously considered pectin (poly galacturonic acid) as a competitor for biofilm acidic polysaccharides, but in this context pectin is also recommended to aid the development of probiotic biofilms.  Thus, I added apples to The Cure, to help the establishment of a new bacterial order.  The rapid result was a return to a happy, regular gut.  This was the duh moment.  Apples = pectin, tomatoes = pectin, and pectin = happy gut flora.  Adding either apples or tomatoes to your diet can make your gut flora happy.  An apple (or tomato) a day keeps the antibiotics away.

The Cure Works

The Cure did what I expected and more.  My wife was also pleased with the rapid initial weight loss and an ongoing loss of about a pound per week.  The continued loss is due to alteration of diet with a further reduction in carbs.  The Cure makes the connection between weight retention and a high carb diet.  Elimination of grains/starch makes weight loss much easier.  Absence of sugar, high fructose corn syrup and other sources of fructose also makes weight loss easier.  The inclusion of saturated fats and elimination of omega-6 vegetable oils is anti-inflammatory and provides an improved sense of well being.  I recommend The Cure, because it simply works.

Saturday, February 6, 2010

Arthritis, Autoimmunity and Arginine Deimidation

Celiac and Antibody Production Against Tissue Transglutaminase as a Model

Arthritis is an autoimmune disease in which the immune system attacks and degrades the connective tissue of joints.  Antibodies against modified amino acids, arginine converted to citrulline, and proteins commonly found in joints, mediate the arthritis disease process.  The development of arthritis mimics the development of gluten intolerance, celiac, in which another enzyme, transglutaminase ( tissue transglutaminase, tTG or TG2) modifies the major gluten protein, gliadin, and antibodies are produced against both modified gliadin and TG2 autoantigen.

Arthritis of Joints Is Like Coeliac of Intestines;  Autoantibodies to Protein Modifying Enzymes

In other articles, I outlined the pathology of gluten intolerance:
  • The major protein of wheat gluten, gliadin, contains long stretches of glutamines.
  • An intestinal enzyme, TG2, converts the glutamines to glutamates by deamination.
  • As TG2 works it binds to gliadin.
  • In celiac, the TG2-gliadin complexes are internalized and fragmented to stimulate antibody production against both TG2 and gliadin.
  • I think that the internalization and processing for antibody stimulation is dependent on the basic triplet found in TG2.

Arthritis Is Mediated by Autoantibodies to Peptidylarginine Deiminase and Citrullinated Proteins

Parallel to the celiac example, in some forms of arthritis, antibodies are produced against an enzyme that modifies proteins.  In arthritis, the enzyme involved, peptidylarginine deiminase (PAD) removes the terminal nitrogen from arginine (deimination) to produce citrullinated proteins.  Antibodies are produced to both PAD and citrullinated proteins.

PAD Also Has a Triplet of Basic Amino Acids for Internalization

I of course wondered if PAD had the same triplet of basic amino acids, e.g. RRK, that I had found on all other autoantigens and allergens.  Examining the sequence of human PAD in the NCBI sequence databases and comparing to other sequences, I found the basic triplet near the carboxy terminus.  The same or an alternative basic triplet was found in PADs from other mammals.

Autoantigens and Predicted Basic Triplets of Amino Acids Reveal the Cause of Arthritis

Arthritis is an inflammatory disease.  That means that without inflammation, arthritis cannot start and if inflammation is inhibited, arthritis cannot progress.  It is likely that arthritis is the result of chronic inflammation plus a precipitating event, such as joint injury or joint infection.  Alternatively, in a manner similar to Hashimoto’s thyroiditis, in which celiac produces anti-TG2 antibodies that attack the TG2 also produced in the thyroid gland, arthritis may be produced by autoantibodies stimulated in the inflammation of other tissues and spreading to the joints.  Celiac is also a risk factor for arthritis.  Trauma-based inflammation of a joint can also result in migration of Clamydia pneumonia (Cpn)-infected macrophages to the site of inflammation.  Cpn could contribute to joint inflammation and promote immunological presentation of autoantigens and autoantibody production.

Stenberg P, Roth B, Wollheim FA.  Peptidylarginine deiminases and the pathogenesis of rheumatoid arthritis: a reflection of the involvement of transglutaminase in coeliac disease.  Eur J Intern Med. 2009 Dec;20(8):749-55. Epub 2009 Sep 19.

Tuesday, February 2, 2010

The Eades Cure Week 4

Meals, Alcohol, Caffeine, but no Dairy

I embarked on The 6 Week Cure for the Middle-Aged Middle to drop ten pounds and reveal my 6-pack.  Now in week 4, I am half way there.  I lost ten pounds (from 188 to 178 lbs) and the visceral fat under the muscle of my belly is greatly diminished, but my 6-pack is yet to be revealed.  My wife dropped a couple of more pounds.  Her blood stats also improved: glucose dropped 10, total cholesterol dropped 30, LDL dropped 20 and triglycerides dropped 26.

The Cure Weeks 3&4
The middle third of The 6-Week Cure is more like a normal low carb diet.  There are three meals a day, but dairy is excluded.  Alcohol, limited to two drinks a week and caffeine (dash of cream, no sugar) are OK.  Plenty of no/low carb veggies, but minimal fruit.  I enjoyed the eggs and bacon for breakfast and popped a whole chicken in the crock pot, after slipping some herb-saturated butter under the skin of the breast.  The second day I pierced the surface of a couple of thick steaks with slivers of garlic and grilled them to produce some lusciously browned edges of fat.

Bad Habits and Portion Control
Alas, I had forgotten that the main reason for going on this gut transition diet, was to destabilize my gut flora, so that I could more easily change my metabolic set point to lose some visceral fat.  I apparently succeeded, because after a couple of days my weight had very easily increased again.  I was clearly taking in too many calories and there was little resistance to weight loss or gain.  During the first two weeks on protein shakes, it was easy to eliminate bad snacking habits and carbs, but the return of normal meals in the 3rd and 4th weeks, made portion control harder.  Before the diet, I would have a poached egg with two strips of bacon.  The Cure version had crept up to two fried eggs, two strips of bacon and a sausage patty.  I was satisfied, but it wasn’t a cure for the middle-aged middle.  The harsh lesson, was that portion sizes still matter.

Energy for Exercise
More normal meals also meant a return of energy and an interest in exercise.  I had only a few times when I felt that my low carb/ high protein & fat meals, stimulated some insulin and lowered my blood sugar.  Common sense prevailed.  I limited my portion sizes, enjoyed coffee and occasional drinks.  I also started walking three miles a day watching the construction for the new community college along Indian Creek.  Another interesting result was my weight training.  I started testing my strength and found that for the first time in forty years I could bench press and crunch my weight, and I could squat twice my weight.  Hand stands and pull ups were also much easier with less weight and more strength.

Altered Gut Flora
Absent PCR tests of my gut flora rRNA genes, I have to settle for empirical changes.  My diet is still predominantly protein and fat, and I haven’t put back as many veggies as The Cure recommends.  [It is winter in Idaho and the veggies in the market are not that appealing.]  That also means that my gut flora are not getting very large meals either, so my stool volume has been cut about in half, compared to before The Cure.  The largest impact is the impression that I can gain or lose weight with each meal.  That makes further weight loss to remove the baby fat covering my 6-pack very approachable.  Unfortunately, I can just reach out and ... feel it jiggle.