NO friend or foe

I am so curious about the diverse roles of NO. While discussing the stimulated production of NO by cytokines in osteoarthritis, the B. Dozin et al in the article, Response of young, aged and osteoarthritic human articular chondrocytes to inflammatory cytokines, mentioned NO as a signaling molecule. NO acts on Gproteins activating the second messenger cyclic GMP to stimulate countlesss down stream effects. The little molecule also binds in the mitochondria matrix inhibiting oxidative phosphorylation. The general role is to kill bacteria but the host cells are often targeted too.Turns out this little radical is even qualified as a neurotransmitter. Important in developing long term memory, NO is also implemented in neuronal cell death. In addition, NO is the main signaler of vasodialation in the periphery.

My question pertains to all of the literature we have read so far in these inflammation patholgies. So often the effective treatments involve suppressing NO sythesis. How can we suppress the destructive functions of this essential molecule while maintaining the beneficial? How do we determine what role NO is playing in the tissue being studied?

The IgA Deficiency, Celiac Disease, and CVID Link

It is known that patients with celiac disease have a higher incidence of IgA deficiency (IgAD) than the general population. This made me wonder why? Going to the literature, I found an article published earlier this year that has shed some light on the association of the two, as well as, interestingly, common variable immunodeficiency (CVID).

As a review, IgAD is the most common primary immunodeficiency (~1 in 500) and often is asymptomatic. There is a higher risk of autoimmune diseases in these people, however, including 10-fold risk of celiac disease. CVID is a disorder of unknown cause that may manifest at various ages with recurrent bacterial infection. Those with CVID have normal numbers of B cells, but are difficult to induce antibody production. IgAD and CVID have been said to be part of a spectrum of defects in antibody production, and IgAD patients can progress to CVID. Celiac disease is a chronic intestinal inflammatory disorder due to gluten intolerance (gluten is an antigen found in wheat, barley and rye) that can only be treated currently with gluten avoidance (which usually works remarkably well when strictly avoided). Its prevalence is quite high in European populations (1%), and celiac disease is strongly associated with HLA DQ2 and DQ8. CVID has been reported in patients with celiac disease (Béchade D, et al. Common variable immunodeficiency and celiac disease. Gastroenterol Clin Biol. 2004 Oct;28(10 Pt 1):909-12.)

Inducible co-stimulator (ICOS) is a T-cell co-stimulatory receptor that, through its interaction with B-cells, influences immunoglobulin class switching and cytokine secretion. Cytotoxic T-lymphocyte-associated protein-4 (CTLA4) is a negative regulator of T-cell function by interacting with B7-1 and B7-2 on an antigen presenting cell. It may have an important role in tolerance induction. Previously, there has been evidence that CTLA4-ICOS is associated with celiac disease. It would make sense that malfunction of these co-stimulators could also play a role in IgAD and CVID given the nature of these immunodeficiencies. If you can’t class switch from IgG to IgA, for instance, you are IgA deficient.

In this European study, 1600 families or patients with celiac disease, IgAD, or CVID were genotyped for 14-18 genetic markers in the CTLA4-ICOS region. The markers are called SNPs, or single nucleotide polymorphisms. An SNP is “a small genetic change, or variation, that can occur within a person's DNA sequence… [that] serve as biological markers for pinpointing a disease on the human genome map, because they are usually located near a gene found to be associated with a certain disease.”
(http://www.ncbi.nlm.nih.gov/About/primer/snps.html).
They used the prevalence of these SNPs to uncover statistically significant associations between CTLA4-ICOS and IgAD (p = 0.0015), CVID (p = 0.0064), and celiac disease (p = 0.0009). The authors theorize that this association may result because of lower expression of ICOS and/or comparatively higher levels of CTLA4 or soluble CTLA4.

This was the first study to report shared risk gene variants other than HLA among people with IgAD, CVID and celiac disease. Gene “hits” to this region could theoretically lead to development of any or a combination of these disorders, thus, at least in part, answering my question as to why people with celiac disease also get IgA deficiency.

The article is found in Genes and Immunity:
Haimila K, et al. The shared CTLA4-ICOS risk locus in celiac disease, IgA deficiency and common variable immunodeficiency. Genes Immun. 2009 Mar;10(2):151-61.

Why More Women Have Osteoarthritis

Women tend to have osteoarthritis at much higher rates than men. According to Alexander Shikhman, MD, PhD, founder of the Institute for Specialized Medicine in Del Mar, CA., and medical director of Restorative Remedies, joints affected by osteoarthritis also vary by gender --- men are more prone to have arthritis in their hips and women tend to have it in the knees or hands.

There are several potential reasons:

1. Biology/anatomy Women’s bodies are designed to give birth and that means the tendons in their lower body are more elastic than men’s. The joints move around more with less stability and therefore more prone to injury. In addition, women’s hips are wider than their knees, their knees are not aligned as straight as men’s which leads to a higher rate of knee injuries, and injuries lead to osteoarthritis later in life.

2. Genetics Osteoarthritis seems to run in families and there appears to be a genetic link among women. Women whose mothers developed osteoarthritis tend to find that they will develop it in the same joints at around the same age as she did.

3. Hormones Researchers believe that female hormones have an effect on the cartilage that locates between the bones of the joints and cushions the bones to prevent pain and allow the joints to move smoothly. Experts in laboratory studies of cells that form cartilage have found that the female hormones estrogen protects cartilage from inflammation and lead to osteoarthritis. Women’s estrogen levels go down after menopause and they lose that protection.

4. Obesity Statistics show that more women than men are obese or severely obese. Extra weight put more pressure on joints and can cause the cartilage between joints wear away faster.

Just Keep Swimming…

For anyone that hasn’t figured it out yet… I might be a little fitness obsessed…

We all know that exercise is good for us and it is important to our day to day health. Well a few years ago when I started looking at the differences between high impact and low impact exercise, I was a swimmer at the time and I was given a pamphlet by my swim coach (who also happened to be my physiology teacher in high school funnily enough) that was all about the health benefits of swimming in the short and long term. The benefit that always stuck in my mind is that swimming helps delay the onset of arthritis later in life. This is due to the perceived difference of gravity when submerged in water the supine position and the very low impact on the joints (big surprise right?)

As I was doing a little research on the disease this week I came across a few articles and reviews that also talk about the positive effects of swimming, in both preventing and treating arthritis. What I have found is that there is truth behind the conjecture that swimming helps delay the onset of arthritis, as well as, it can be used to treat arthritis to a certain extent. The exercise itself can be used to help reduce the inflammation and keep the joint from becoming too stiff. Aside from these benefits the arthritic patients also receive all the same benefits as one would from doing cardiovascular exercise.

Cool huh? So maybe a little lesson from the regal tang Dory would not go amiss, “just keep swimming” to delay the onset of arthritis.

If you are interested: Danneskiold-Samsoe, B., K. Lyngberg, T. Risum, and M. Telling. "The effect of water exercise therapy given to patients with rheumatoid arthritis." Scand J Rehabil Med. 19.1 (1987): 31-35.

Adjuvant Produces 200-Fold Increase in Antibody Responses

The San Diego based biopharmaceutical company (Vical Inc) recently published a couple of articles (1,2) in a special edition of the Journal "Vaccine" regarding the company's patented adjuvant Vaxfectin (R). They managed to demonstrate in mice that when commercially acquired Sanofi-Pasteur Fluzone (R) - a seasonal trivalent influenza vaccine (TIV) - is formulated with Vaxfectin(R) it managed to produce antibody responses that are 200-fold higher than unadjuvanted seasonal (TIV). Furthermore they also successfully registered a remarkable 10-fold dose-sparing effect. The publication of these data came less than a week after information emerged about apparent hiccups in the manufacturing process of the H1N1 vaccine, during a meeting of experts on the Advisory Committee on Immunization Practices, which makes recommendations to CDC. Production of H1N1 vaccine lagged behind schedule due to vaccine immunogen harvested from chicken eggs falling short of expected yields, with some manufacturers experiencing a 3-to-4-fold yield, less than expected. CDC director Thomas Frieden MD,MPH emphasized at a press conference that the agency, despite the shortage of vaccine, will not be switching H1N1 vaccine production techniques from the traditional "antiquated" chicken egg approach, to a more modern - and touted as a faster means of production - "cell culture" method. His reasoning which makes sense to me was that the H1N1 pandemic has a level of severity similar to the seasonal flu, even though the age-specific risk categories are strikingly different. Therefore while the publication of Vical Inc's results is indeed exciting, the US Food and Drug Admisnitration (FDA) is yet to approve the addition of adjuvant and subsequent modification of vaccine in order to amplify immune response. It is also important to note that these were preclinical data of studies conducted in mice.
(1) Hartikka Jet al. Vaxfectin(R), a cationic lipid-based adjuvant for protein-based influenza vaccines. Vaccine 2009;27:6399-6403
(2) Shlapobersky M et al. Vaxfectin(R)-adjuvanted seasonal influenza protein vaccine: Correlation of systemic and local immunological markers with formulation parameters. Vaccine 2009; 27:6404-6410
(3) Lowes, R. CDC defends reliance on "antiquated" H1N1 vaccine production despite shortages. http://www.medscape.com/viewarticle/711245

Rheumatoid arthritis,canabis

The first study to use a cannabis-based medicine for treating rheumatoid arthritis has found that it has a significant effect on easing pain and on suppressing the disease.
There is anecdotal evidence that cannabis can provide pain relief for people with rheumatoid arthritis (RA).The researchers found that in comparison with the placebo, patients who had taken the cannabis had statistically significant improvements in pain on movement, pain at rest, quality of sleep, inflammation

Gold salts for rheumatoid arthritis

It is not understood exactly how gold works to treat rheumatoid arthritis. But gold salts appear to accumulate slowly in the body and, over time, they reduce inflammation and slow the progression of rheumatoid arthritis.Gold injections are given every week for the first 22 weeks. After that, gold may be given less often if it is working.Gold is used to reduce inflammation and slow disease progression in people with rheumatoid arthritis. Gold is not usually the first treatment given to people with rheumatoid arthritis, since methotrexate and other disease-modifying antirheumatic drugs are available. Gold salts taken by mouth (oral) have not been found to be as effective as gold injections, and it can take up to 6 months before benefits are noticed from oral gold salts.

Side effects may develop after a significant amount of gold has accumulated in the body.

Oral gold has fewer side effects than gold injected into the muscle. Common side effects of oral gold include:

• Decreased appetite, nausea, and diarrhea.
• Problems with the skin, blood, kidneys, or lungs (rare).

Common side effects of injected gold include:

• An itchy skin rash.
• Mouth sores.

Rarer side effects include:

• Kidney problems (kidney damage that causes loss of protein in the urine).
• Suppression of blood cell production, which may increase the risk of infection or serious bleeding. (A return to normal blood cell production may take several weeks after the drug is no longer taken.)

Extremely rare side effects include bowel or lung inflammation.

Age At Virus Acquisition and Progression to a Chronic State

In areas where HBV infection is endemic, transmission from mother to child during the birthing process is a major source of virus acquisition. Infants living in such areas also face a high risk of infection during the first year of life, through contact with HBV positive household members. 

 Interestingly, one of the major factors that influences the transition of HBV from an acute to a chronic infection is based on age at acquisition of the virus. In areas where the HBV virus is acquired perinatally, the immune system is not able to distinguish a difference between the virus and the host. Because of this, there is no immunologic response to hepatocyte-membrane HBV proteins – which are associated with acute hepatitis infections. Instead, chronic, lifelong HBV infections are established in 90% of perinatally infected individuals.

 In these perinatally infected individuals, low-level liver injury occurs, and accounts for approximately 40% of lifetime death in HBV positive men. For unknown reasons, the lifetime risk of death due to HBV-related liver injury is slightly lower in women.

 Dienstag, Jules L.

 2008            Hepatitis B Virus Infection. New England Journal of Medicine 359(14):1486-1503.

Immunosuppression post 1 follow up

As queries by some very intelligent readers have come in, I would like to explain further the points that I may have missed on earlier. when I mentioned biomarkers I meant for example in kidney transplantation, after the procedure when on long term immunosuppression there is kidney injury (either due to drug nephrotoxicity or chronic rejection caused by insufficient immunosuppression)the current marker used in clinic fail to detect it until aproximately more than 50% damage to the organ is done much of which can be irreversible. If we catch the injury early on as its happening we can modulate immunosuppressant dosage accordingly. we can increase the dose if there is less immunosuppression causing chronic rejection and decrease the dosage if there is immunosuppression drug toxicity. Unfortunately in clinic right now, first the detection is late second due to similar injury manifestation by both chronic rejection and drug nephrotoxicity, there isn't yet a measure to find out which one of them is causing the injury, where detection means totally different preventive measure as I mentioned earlier. So to find biomarkers that can detect organ injury early on post transplantation is one of the things that can change the graft and patient survival rates. An ideal biomarker should be non-invasive (lets say from urine / blood. Invasive would be a tissue biopsy), it should be inherently involved in the biochemical pathways that result in the disease symptom so that if there is a slight change in the state of the disease we are readily able to detect it via change in concentration/state of this biomarker. Considering kidney transplanation, some biomolecule in urine will be an ideal candidate because it will be intimately associated with the kidney (because organ in question produces the biomarker directly). Today creatinine in blood and urine (along with tissue biopsy and histology to see damage)is used as a gold standard in transplantation related kidney injury, but even for kidney injury it has shown be quite insensitive. Addressing local immunosuppression, yes it seems almost sci-fi to think about something like that given the complexity and exposure to everything in the body, but it may not be as far fetched. Though I have very limited knowledge about this but I have heard of some very interesting theories people are working on but it may be too preliminary to mention it here. our best bet is still a system-wide efficient and non toxic immunosuppression along with very sensitive biomarkers to detect any adverse effects. The success of a transplant is based on tons of factors because anything in body is everything and anything is connected to everything. for example if there is a liver transplant and popular immunosuppressants are in effect then there are very high chances there will be kidney specific injury. if kidney is injured it wont be able to do its various jobs (filtering, BP etc.) and we will have system wide effects where it will be hard to pinpoint what caused it. While there maybe no such thing as ideal immunosuppression (because we are doing something that nature did not intend upon happening) with very diligent patient monitoring with current day immunosuppressants (please don't quote me on this), in cases people have lived with their kidney grafts for as long as 20-25 years. Majority of kidney transplants see anywhere from 10-14 years until they need a retransplant.

Immunotoxin and Cancer Therapy

I recently became aware of a class of cancer pharmaceuticals which are generally called immunotoxins. Immunotoxins consist of a cancer specific antibody attached to a bacterial or plant toxin. The mechanism of action is via interacting with a surface receptor or protein, the toxin can then be internalized into the cancer cell and eventually reach the cytosol where protein synthesis can be stopped. Immunotoxins are also better suited for use of cancer treatment for B and T-cell malignancies because in these patients the immune system is suppressed and therefore neutralizing antibodies are not made against the toxin. Current FDA approved drugs are Bevacizumab, Cetuximab, and Panitumumab, so the overall diversity of available drugs is limited. Some of the apparent reason's for the lack of drugs is immunogenicity and toxicity issues.

A paper I recently read from a group at the National Institutes of Health, has addressed the immunogenicity issues as they relate to the toxin via mutating large hydrophilic amino acids on the surface of their toxin. This group used an immunotoxin BL22, which was previously shown by their group in clinical trials to be successful in inducing remission in patients with drug-resistant Hairy cell leukemia. "BL22 targets CD22 positive malignancies and is composed of an anti-CD22 Fv fused to a 38-kDa fragment of Psudomonas exotoxin A."

The group found that they could mutate eight residues of the toxin and still maintain the cytotoxicity of the drug, but decrease the immunogenicity and antigenicity in mice ( I have further read in the literature this drug is now in clinical trials as well). Overall, this appears to be a better drug than the parent BL22 and still retains the efficacious cytotoxicity desired for a a cancer drug.

Questions that I have regarding immunotoxins are:

Now that the immunogenicity and antigenicity issues regarding the toxin have been somewhat addressed, will these drugs be more effective in patients with solid tumors? Patients with solid tumors were previously reported to not have successful outcomes with immunotoxin drugs due to their ability to elicit neutralizing antibodies, whereas patients with B and T-cell malignancies were unable to do this because their immune systems are suppressed.

There does not appear to be a consensus between the current FDA approved drugs regarding the type of monoclonal antibody used

Bevacizumab--humanized monoclonal

Cetuximab--chimeric monoclonal

Panitumumab--fully human

BL22 or HA22--unable to find

I am wondering if any of you think that by using the least foreign monoclonal antibody ("fully human") and a toxin where the epitopes have been removed to the degree that the antigenicity and immunogenicity is minimized, but the toxin retains full cytotoxicity, could these drugs be more suitable for treatment of solid tumors?

Onda, M., R. Beers, L. Xiang, S. Nagata, Q. Wang, and I. Pastan. An immunotoxin with greatly reduced immunogenicity by identification and removal of B cell epitopes. PNAS (2008) 32(105): 11311-11316.

Ankylosing spondylitis

Ankylosing spondylitis (AS); also known as Bechterew disease; Marie Strumpell disease), an autoimmune seronegative spondyloarthropathy, is a painful chronic inflammatory arthritis punctuated by exacerbations (‘flares’) and quiescent periods. It primarily affects the spine and sacroiliac joints and eventually causes fusion and rigidity of the spine (‘bamboo spine’). Ankylosing spondylitis varies widely in prognosis and outcome. It is also associated with ulcerative colitis, Crohn’s disease, psoriasis and Reiter’s syndrome (uveitis).
Ankylosing spondylitis occurs in 1% of men and 0.5% of women in Caucasians. It is more prevalent in males with a peak age onset of 20–30 years. Men tend to have more severe spinal and pelvic disease, whereas women have peripheral joint (knees, wrists, ankles, hips) involvement. Symptoms develop before the third decade of life in 80% of patients with AS. Less than 5% of patients develop AS in the fourth decade. Juvenile onset (age 10–16 years) AS is a more severe disease and occurs in 4%of AS.
The initiating cause of AS is not known but environmental factors (unidentified bacterial or viral agents), susceptibility genes (HLA-B27), gender, age and ethnicity play a role. Overall, sporadic AS is more severe than familial disease. Although only 5% of HLA-B27 positive individuals develop AS, 90–95% of patients with AS possess HLA-B27 alleles.
Ankylosing spondylitis is characterised by sacroilitis, peripheral arthropathy, enthesopathy (pathological changes at the sites of insertion of ligaments and tendons), and the absence of rheumatoid factor. The symptoms of AS usually begin between the ages of 15 and 40 years with persistent pain and morning stiffness (worse at rest but improves with exercise) in the lower spine and the sacroiliac joints.
Extra-articular manifestations are associated with more severe AS and those relevant to anaesthesia involve the cardiovascular system, lungs and skin.