FUDAN UNIVERSITY Asthma. eczema Mechanism and genetics Michael widjaja 1/20/2010 Asthma and eczema are two diseases that are affected by allergies. In this paper, we will learn of the respective symptoms and treatment of each disease. Furthermore, we will attempt to divulge the mechanism and origins of both diseases. Following the understanding of both diseases we will examine any links between the two
FUDAN UNIVERSITY Asthma,Eczema Mechanism and Genetics Michael Widjaja 1/20/2010 Asthma and eczema are two diseases that are affected by allergies. In this paper, we will learn of the respective symptoms and treatment of each disease. Furthermore, we will attempt to divulge the mechanism and origins of both diseases. Following the understanding of both diseases we will examine any links between the two
Asthma is a disease in which expiration of the lungs is obstructed by two parts One part is by overstimulation of the smooth muscles of the bronchioles, causing the smooth muscles to contract, constricting the airways. The other part of asthma is overproduction of mucus. It is often stimulated by allergies, drastic change in temperature, exercise, and sickness While there is no direct gene linked to asthma, family history tends to show that genetics do play an important factor Eczema' s symptoms consist of dry itchy skin, redness, cracking, oozing and bleeding. Several causes of eczema include allergies, skin irritants, dry weather, and sweat. Similar to asthma, there is also no direct gene linked to asthma, however family history can show that genetics also play an important factor Allergies Both diseases are stimulated by allergies. Allergies is when the human body responds to a harmless foreign particle as a harmful antigen. When an antigen enters a body the plasma cell produces Immunoglobulin e(ge). ige binds to the surface of mast cells. Future exposures to antigen results in binding of antigen to surface bound E. This then leads to mast cells degranulation, releasing steroids histamine and leukotriene Leukotriene promotes contraction the bronchioles, narrowing the air pathway. Histamine increases permeability causing capillary leakage and edema. this causes swelling and greater production of mucus within the air pathways. Histamine
Symptoms Asthma is a disease in which expiration of the lungs is obstructed by two parts. One part is by overstimulation of the smooth muscles of the bronchioles, causing the smooth muscles to contract, constricting the airways. The other part of asthma is overproduction of mucus. It is often stimulated by allergies, drastic change in temperature, exercise, and sickness. While there is no direct gene linked to asthma, family history tends to show that genetics do play an important factor. Eczema’s symptoms consist of dry itchy skin, redness, cracking, oozing and bleeding. Several causes of eczema include allergies, skin irritants, dry weather, and sweat. Similar to asthma, there is also no direct gene linked to asthma, however family history can show that genetics also play an important factor. Allergies Both diseases are stimulated by allergies. Allergies is when the human body responds to a harmless foreign particle as a harmful antigen. When an antigen enters a body, the plasma cell produces Immunoglobulin E(IgE). IgE binds to the surface of mast cells. Future exposures to antigen results in binding of antigen to surface bound IgE. This then leads to mast cells degranulation, releasing steroids histamine and leukotriene. Leukotriene promotes contraction the bronchioles, narrowing the air pathway. Histamine increases permeability causing capillary leakage and edema. This causes swelling and greater production of mucus within the air pathways. Histamine
is also involved in allergic reactions for eczema. In this case, it causes a swelling itchy Treatments of asthma involve two pathways. One is to treat inflammation of the airways by using inhaled corticosteroids. this pathway is considered preventive medicine, as the patient is administered the drug even when symptoms of asthma are not displayed. The other pathway is the inhalation of bronchodilators which relax the smooth muscles of the bronchioles this is used in cases of asthma attacks for immediate relief Genetic and environmental factors of asthma Through studies examining parent child relationships it was determined that a childs chance of getting asthma increased when both parents had asthma. this indicated there were hereditary factors in play. In a different study it was observed that in cases where one twin had asthma the other did not necessarily develop asthma as well. This demonstrates that not only are there are hereditary factors, but there are environmental factors as well, because if it was just hereditary then both twins must either develop asthma or not develop asthma. this is not the case As there is no one gene that is related to asthma, there are multiple genes inked to asthma. most of these genes are related to the immune system or inflammation. One such gene would be tGFB1 which plays an important role in control of expression of antibodies. Another gene would be aDAM33, which causes the bronchiole smooth muscles to be hypersensitive. Studies however have been
is also involved in allergic reactions for eczema. In this case, it causes a swelling itchy redness. Treatments of asthma involve two pathways. One is to treat inflammation of the airways by using inhaled corticosteroids. This pathway is considered preventive medicine, as the patient is administered the drug even when symptoms of asthma are not displayed. The other pathway is the inhalation of bronchodilators which relax the smooth muscles of the bronchioles. This is used in cases of asthma attacks for immediate relief. Genetic and environmental factors of asthma Through studies examining parent child relationships it was determined that a child’s chance of getting asthma increased when both parents had asthma. This indicated there were hereditary factors in play. In a different study, it was observed that in cases where one twin had asthma the other did not necessarily develop asthma as well. This demonstrates that not only are there are hereditary factors, but there are environmental factors as well, because if it was just hereditary, then both twins must either develop asthma or not develop asthma. This is not the case. As there is no one gene that is related to asthma, there are multiple genes linked to asthma. Most of these genes are related to the immune system or inflammation. One such gene would be TGFB1 which plays an important role in control of expression of antibodies. Another gene would be ADAM33, which causes the bronchiole smooth muscles to be hypersensitive. Studies however have been
inconsistent. Where in same cases of asthmatic patients certain genes are a factor in other asthmatic patients certain genes are a nonfactor Environmental factors that can trigger asthma consist of a two parts. One part includes tobacco smoke, dust, and air pollutants, which would irritate the lungs. The other factors are of which would affect the immune system this includes caesarean section and psychological stress Genetic and environmental factors of eczema Similar to asthma, no one gene affects eczema However one gene that certainly play portant role in eczema is the filaggrin gene this gene encodes the protein that forms a protective barrier that keeps moisture in and infectious organisms out. Another gene is SPiNK5 which plays a role in anti-inflammatory and antimicrobial protection of mucous epithelia. one gene plays a role in keeping the antigen out of the body while the other gene affects how the body would respond to said antigen As with asthma, environmental factors also play a factor in the development of eczema. this also stems from a wide range of allergens and immune system changing factors Link between asthma and eczema There has been an established link between asthma and eczema. Fifty to seventy percent of children with severe eczema will develop asthma this is known as
inconsistent. Where in same cases of asthmatic patients certain genes are a factor, in other asthmatic patients certain genes are a nonfactor. Environmental factors that can trigger asthma consist of a two parts. One part includes tobacco smoke, dust, and air pollutants, which would irritate the lungs. The other factors are of which would affect the immune system. This includes caesarean section and psychological stress. Genetic and environmental factors of eczema Similar to asthma, no one gene affects eczema. However one gene that certainly plays an important role in eczema is the Filaggrin gene. This gene encodes the protein that forms a protective barrier that keeps moisture in and infectious organisms out. Another gene is SPINK5 which plays a role in anti-inflammatory and antimicrobial protection of mucous epithelia. One gene plays a role in keeping the antigen out of the body, while the other gene affects how the body would respond to said antigen. As with asthma, environmental factors also play a factor in the development of eczema. This also stems from a wide range of allergens and immune system changing factors. Link between asthma and eczema There has been an established link between asthma and eczema. Fifty to seventy percent of children with severe eczema will develop asthma. This is known as
atopic march. Recent research done by Washington University School of Medicine found a cause to atopic march Research was done on mice examining TSLP(thymic stromal lymphopoietin) The gene that encodes for tslP is found on chromosome 5 Mice engineered to have defective skin similar to eczema in humans produced TSLP and eventually developed asthma. Another batch of mice with normal skin was engineered to overproduce TSLP yet also developed asthma TSLP is secreted into the blood stream when the skin is damaged indicating that there has been a breach in the protective barrier and further protections are necessary. Thus it helps bring about inflammation of the skin. Both lung and skin come in contact with the open environment. When tSLP flows in the bloodstream to the lungs it also causes inflammation. tslP thus causes lungs to be extremely sensitive to allergens. Conclusion While tsLP gene plays an important factor in the development of eczema and asthma, it is not the only factor. We have learned that the nature of eczema and asthma is an overactive immune system responding to allergens. thus any genes that have a factor in the hypersensitivity of the immune system may play a strong role in the development of eczema and asthma. While multiple genes play a factor in this environmental factors also play a strong role in triggering asthma and eczema
atopic march. Recent research done by Washington University School of Medicine found a cause to atopic march. Research was done on mice examining TSLP(thymic stromal lymphopoietin). The gene that encodes for TSLP is found on chromosome 5. Mice engineered to have defective skin similar to eczema in humans produced TSLP and eventually developed asthma. Another batch of mice with normal skin was engineered to overproduce TSLP yet also developed asthma. TSLP is secreted into the blood stream when the skin is damaged, indicating that there has been a breach in the protective barrier and further protections are necessary. Thus it helps bring about inflammation of the skin. Both lung and skin come in contact with the open environment. When TSLP flows in the bloodstream to the lungs, it also causes inflammation. TSLP thus causes lungs to be extremely sensitive to allergens. Conclusion While TSLP gene plays an important factor in the development of eczema and asthma, it is not the only factor. We have learned that the nature of eczema and asthma is an overactive immune system responding to allergens. Thus any genes that have a factor in the hypersensitivity of the immune system may play a strong role in the development of eczema and asthma. While multiple genes play a factor in this, environmental factors also play a strong role in triggering asthma and eczema
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Bibliography http://acc6.its.brooklyn.cuny.edu/~scintech/asthma/Genetics2.htm http://www.mamashealth.com/allergies/breathbet.asp http://en.wikipedia.org/wiki/Asthma http://en.wikipedia.org/wiki/Eczema http://www.blisstree.com/articles/filaggrin-gene-and-eczema/ http://www.thetech.org/genetics/ask.php?id=161 http://www.blisstree.com/articles/filaggrin-gene-and-eczema/ http://news.bbc.co.uk/2/hi/health/8055038.stm http://www.news-medical.net/news/2009/05/18/Researchers-look-at-eczemaasthma-link.aspx