A number of afflictions of humans in the modern era are a result of the fact that natural selection adapted us to environments so different than the environments of modern industrial societies. Obesity was not much of a problem in the past because for most of human history there was rarely much surplus food. The same is the case with salt cravings where, again, in the past there was usually not enough sodium in the foods our ancestors had to eat. Similarly, drug and alcohol addiction are obviously the result of the lack of human adaptiveness to substances they rarely encountered in the past. However, alcoholism susceptibility is less frequent among Mediterranean populations that have been growing grapes and making wine for centuries. So there are human populations that have developed at least partial genetic adaptations to ethanol consumption.
Some scientists have been advancing theories to explain some auto-immune disorders as being the result of lack of exposure to diseases that used to be common in the human past. Among the diseases suspected as being a consequence of lack of exposure to diseases are the painful digestive tract disorders inflammatory bowel disorder (IBD) and Crohn's Disease. Joel Weinstock MD, a professor of internal medicine at University of Iowa, and colleagues have demonstrated that eggs of pig whipworm, when consumed by suffers of Crohn's Disease (CD) and Ulcerative Colitis (UC), greatly reduce symptoms of those diseases.
). To assess safety and efficacy with repetitive doses, two patients with CD and two with UC were given 2500 ova at 3-wk intervals as maintenance treatment using the same evaluation parameters. RESULTS: During the treatment and observation period, all patients improved clinically without any adverse clinical events or laboratory abnormalities. Three of the four patients with CD entered remission according to the Crohn's Disease Activity Index; the fourth patient experienced a clinical response (reduction of 151) but did not achieve remission. Patients with UC experienced a reduction of the Clinical Colitis Activity Index to 57% of baseline. According to the IBD Quality of Life Index, six of seven patients (86%) achieved remission. The benefit derived from the initial dose was temporary. In the maintenance period, multiple doses again caused no adverse effects and sustained clinical improvement in all patients treated every 3 wk for >28 wk. CONCLUSIONS: This open trial demonstrates that it is safe to administer eggs from the porcine whipworm, Trichuris suis, to patients with CD and UC. It also demonstrates improvement in the common clinical indices used to describe disease activity. The benefit was temporary in some patients with a single dose, but it could be prolonged with maintenance therapy every 3 wk. The study suggests that it is possible to downregulate aberrant intestinal inflammation in humans with helminths.
At the moment the concoction cannot be stored for long, so doctors or hospitals would have to prepare fresh batches of the eggs for their patients. But a new German company called BioCure, whose sister company BioMonde sells leeches and maggots for treating wounds, hopes it will soon solve the storage problem.
If you find this idea completely revolting and perversely want to be even more revolted then see a picture of these worms or see this other picture of the worms so you can intensify your feelings of being grossed out by the idea of eating digestive tract worm eggs. Yes, picture worms wriggling around in your guts and say "Oh that is so gross! That is so disgusting!"
Okay, are you done imagining swallowing slimy worms that wriggle around in your mouth? Back to the science.
A pair of researchers at Scripps Research Institute, Nora Sarvetnick and Cecile King, are proposing a mechanism by which a lack of expsoure to pathogens causes autoimmune responses that cause diseases such as type I diabetes and rheumatoid arthritis.
According to the new hypothesis that Nora Sarvetnick and her colleague Cecile King are proposing, the root cause of autoimmunity is a failure to make an adequate response to an infection—in other words, an immune system that is not working hard enough (one that is hyporesponsive). This hyporesponsiveness creates a condition known as lymphopenia, where there is a reduction in the number of T cells in the body. Often people with autoimmune diseases like Type 1 diabetes, lupus, and rheumatoid arthritis have low T cell numbers.
If the body detects low levels of T cells, it resorts to homeostatic expansion, a mechanism that has never been associated with autoimmunity before. Under homeostatic expansion, growth signals stimulate the existing T cells in the body to divide and multiply.
This homeostatic process should normally fill the body, but sometimes that does not happen due to disrupted growth signals or a viral infection that causes the number of T cells to go down even as the body is trying to increase their numbers. These are the conditions that lead to autoimmunity, says Sarvetnick.
Sarvetnick, King, and colleagues Alex Ilic and Kersten Koelsch have shown that in a mouse strain genetically engineered to develop type I diabetes that they can prevent the development of the diabetes by feeding them bacterial cell wall components that keep up their T cell counts.
In their paper, Sarvetnick and her colleagues showed that NOD mice can be protected against diabetes by challenging them with a swill of bacterial cell wall components called CFA, which increased the T cell count and curtailed the development of diabetes in the mice.
To show that this effect was due to the increase in T cell count following the CFA administration and not some other cause, they passively stimulated the immune systems of NOD mice by infusing them with T cells. These infusions also prevented the NOD mice from developing diabetes.
According to Sarvetnick's and King's hypothesis, the protection against diabetes results from exposure to these pathogens because it keeps the body full of immune cells. Increased numbers of T cells act as a buffer against the emergence of self-reactive T cells by shutting down homeostatic expansion.
This hypothesis could explain a discrepancy in the number of cases of autoimmune disease in developed and developing countries. Disease rates have been on the rise in developed countries in the last 50 years compared to their developing neighbors, presumably because people in less developed countries are exposed to more pathogens.
Now, some of you may rather eat worm eggs or even wriggling worm eggs to treat your autoimmune disorders. But I think Sarvetnick, King, and company are performing a useful public service by searching for a treatment based on bacterial cell wall components.
In the longer run expect to see the development of vaccines that stimulate the immune system in ways that greatly decrease the odds of development of autoimmune disorders. Some of these future vaccines may even cure existing autoimmune disorders.
|Share |||Randall Parker, 2004 April 22 12:29 PM Biotech Therapies|