Cellulite is a common complex cosmetic problem for many post-adolescent women. It mainly affects the buttocks and thighs, although other areas of the body, such as the abdomen, may also be affected. It has been deemed unattractive and undesired by many as it gives the skin an orange-peel-like, dimpled appearance. Many people with severe cellulite seek effective treatment options and wish to know how to prevent the condition. However, the pathology of the condition is not fully understood, making it more difficult to cure or prevent its development.
Previously, it has been suggested that the presence of excess subcutaneous fat may be a major cause of cellulite, but recent research indicates that the formation of cellulite is more complex than we thought. Hormonal factors, the microcirculatory system, the extracellular matrix, subtle inflammatory alterations and possibly factors produced by adipocytes (fat cells) may play important roles in the formation of cellulite. To more thoroughly understand the pathophysiology of this widespread cosmetic issue, researchers investigated genetic factors that may contribute to its development.
In this study, 200 lean women with cellulite (cases) were enrolled and matched by age and BMI to an additional 200 lean women without cellulite (controls). All participants were of Italian descent. There were 6 groups of genes investigated, including 15 candidate genes that were selected due to their biological relevance. The target polymorphisms of these genes were further selected based on prior evidence of potential functionality and validated allele frequency. The severity of cellulite in this study was measured by the 4-stage Nurnberger–Muller scale (grade ≥ 2 for cases, grade 0 for controls). When genotype distribution and allele frequency were compared between groups, the polymorphisms of two genes showed significant associations with cellulite development. One of these polymorphisms, the rare T allele of rs11549465 in the hypoxia-inducible factor-1 alpha (HIF1A) gene, was associated with a reduced risk of cellulite. The alpha-subunit of HIF1, a transcription factor, is known to be directly regulated by oxygen tension. During times of excess caloric intake and in early stages of adipose tissue expansion, the microenvironment of the adipose tissue rapidly becomes hypoxic because of the lack of an adequate vascular network. Under hypoxic conditions, the level of HIF1A increases, promoting adipose tissue fibrosis and a local state of inflammation. Intriguingly, HIF1A mRNA has been reported to be upregulated in the fat of obese humans and is positively correlated with BMI. The HIF1A mutation has shown a significantly reduced HIF1A activity for the mutant (T) allele compared to the wild type.
Although cellulite tends to be a gender-specific condition, no significant differences in the oestrogen receptor gene polymorphisms were shown in this study. It is thus possible that the differences in the prevalence of cellulite among females may not be chiefly influenced by polymorphic variation in the oestrogen receptor system, but rather in genes influencing local adipose tissue microcirculation and fibrogenic response to hypoxia. Based on the role of HIF1A on development of this condition, strategies aiming to improve the adipose oxygen saturation may also be worthy of investigation. Read more about the study here: https://www.ncbi.nlm.nih.gov/pubmed/20059631
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