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UltraViolet (UV) Therapy for IBD and Crohn's Disease

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Ultraviolet Light (UV)

UltraViolet (UV) light therapy has been used to successfully treat skin conditions, such as psoriasis and eczema. UV therapy has also shown improvement for sleep disorders, dementia, as well as seasonal affective disorder (SAD). UV radiation is defined as electromagnetic radiation with wavelengths between 40nm and 400nm. The two types of UV light of import to health are UVA (320nm - 400nm) and UVB (290nm - 320nm). [1]

UV Light and Crohn's Disease

Crohn's Disease (CD) and Inflammatory Bowel Disease (IBD) can often cause malabsorbtion and lead to Nutrient Deficiencies. One condition, Hypovitamintosis D, or low serum levels of Vitamin D, is of particular importance to CD and IBD patients due to its myriad of health-related effects, including proper immune system functioning. Studies have shown a regional effect in number of Crohns disease cases and suggest the UV light exposure (or lack of UV light exposure) could be a contributing factor to low levels of Vitamin D and may be a risk factor for Crohn's disease. [7]

Low serum levels of Vitamin D have been shown to increase, and can even normalize, with skin exposure to UV light sources, via solar radiation (the Sun) or UV Lamps (i.e. Tanning booths). Health Physics Society. Specialists in Radiation Safety][1]

Potential Risks With Skin Exposure to UV Light

Increasing skin exposure to UV light is not without it's risks. Although UV exposure can increase Vitamin D levels in the body, it can be damaging to DNA and protein in skin cells. Tanning beds have been shown to increase the risk of skin melanoma, basal cell carcnoma (BCC), and squamous cell carcinomas (SCC) and can damage the skinís immune response. There also may be increased risk in melanoma of the eyes.[6]

The damaging effects of UVA and UVB exposure is due to liberation of Reactive Oxygen Species (ROS) within the skin. ROS can damage cell proteins or DNA leading to cell death, gene mutations or cancer. UVB acts directly on all layers of the epidermis, whereas UVA is lower energy and primarily damaging in highly pigmented skin areas (i.e. freckles and moles).

UV is a known carcinogen (cancer-causing agent) due to DNA damage and is a leading cause of melanoma (UVA), or skin cancers in general (UVB).

Read About Miss Maryland's Battle with Melanoma

UV exposure can lead to direct DNA damage or may induce cross-linking of thymidine moleculeswithin the DNA (TT - Dimers). DNA damage can be repaired by multiple cellular DNA - Damage Repair Mechanisms. Sometimes, the damaged DNA is not repaired and may be due to a genetic mutation within the DNA - Damage Repair pathway, multiple of which are well-known to increase the likelihood of developing cancers (i.e. gene mutations in BRCA1, BRCA2, p53, p21)[5].

Tanning beds have been shown to cause DNA damage and DNA strand breaks in skin cells. UV from tanning bed sources can also cause p53 mutations at the gene and at the protein level. Aberrant or nonfunctional p53 is known to correlate with aggressive cancers and can be poor prognostic indicator.

UV light penetrates through the epidermis to the basal layer, to keratinocyte stem cells and melanocytes. Mutations have been shown in all of these cell types causing squamous cell carcinoma (scc), basal cell carcinoma(bcc), and melanoma(an aggressive form os skin cancer).

- BCC and SCC have low risk of mortality when caught early but have high rates of recurrance and double the risk of getting cancer in non-skin regions of the body (lung, colon, breast) [2].

- Recently, a variant of BCC and SCC has been described, called "aggressive non-melanoma". These lesions grow large and have increased invasive behavior. A study at The University of Pennsylvania (Philadelphia, PA) showed that following their removal, nearly half of these "aggressive" non-melanoma lesions returned and more than 22% metastasized into lymph nodes. [3]

Diseases that cause immunosuppression or drug-induced immunosuppression (i.e. prednisone) can increase the likelihood on a person developing cancer (skin cancers and non-skin cancers). The risk of skin cancer is further amplified by UV radiation exposure. [4]

One physician at The Skin Cancer Foundation recommends all of her immune suppressed patients adopt a "complete sun protection program" consisting of sunblock and clothing UV protection. She adds that if patients are worried about health related effects of lowering serum levels of Vitamin D, they should take Vitamin D supplements and eat a Vitamin D - rich diet, including such examples as salmon, egg yolk and fortefied milk. [4]
- These supplement and food-related nutritional suggestions may be of help to immunosuppressed patients in general; however, Crohn's and IBD patients, especially with severe symptoms leading to malabsorbtion may receive little help in alleviating Hypovitamintosis D if adopting these dietary and UV-limiting measures, and may instead further exacerbate their disease.

References

1. Health Physics Society. Specialists in Radiation Safety

2. Nonmelanoma Skin Cancer Incidence Jumps by Approximately 300 Percent.[www.skincancer.org].

3. Melanomas Aren't the Only Dangerous Skin Cancers. Sun & Skin News, 2001; 18(4). [www.skincancer.org]

4. "Immunosuppression & Skin Cancer." The Skin Cancer Foundation

5. Rastogi RP, Richa, Kumar A, et al. Molecular Mechanisms of Ultraviolet Radiation-Induced DNA Damage and Repair. J Nucleic Acids. 2010; Article ID 592980. http://www.ncbi.nlm.nih.gov/pmc/arti...010-592980.pdf

6. Exposure to Artificial UV Radiation and Skin Cancer. World Health Organization, International Agency for Research on Cancer.

7. http://www.news-medical.net/news/201...onditions.aspx

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