A new study has found that estrogen was responsible for slower wound healing in females than males. The researchers from University of California Berkeley tested this theory by causing a mild injury to the cornea layer in the eyes of mice.
They analyzed and monitored their wound healing through image analysis and the formation of a protective lipid pathway.
“To test the role of estrogen, they gave the male mice estrogen eye drops or drugs to activate specific estrogen receptors.” The researchers found that estrogen negatively affected the internal lipid circuit of two important components, 15-lipoxgenase and Lipoxin A4, which have been determined to provide a protective pathway in many diseases.
“This pathway balances the activity of pro-inflammatory signals to promote wound healing and to keep inflammation with safe ranges,” according to Science Daily.
The researchers reported that “our results demonstrated the first time a sex-specific difference in corneal reparative response ...” and, “these findings may provide novel insights into the etiology of sex-specific ocular inflammatory diseases.”
The study was published in the April edition of The FASEB Journal. The Editor-in-Chief of the journal, Gerald Weissmann, M.D., commented to Science Daily that "this study goes a long way to explaining gender differences in inflammation and its resolution.”
He went on to say, "It's long been known that women suffer more than men from chronic inflammatory diseases such as lupus or rheumatoid arthritis; this study suggests that estrogen itself is responsible for that difference and pinpoints the molecular pathways that estrogen affects.”
While it is true that diseases such as lupus have a much greater incidence in women than men by nine to one, it has yet to be determined exactly what the role estrogen has in this systemic disease.
It seems premature to apply knowledge gained from this single study on mice to understanding the immune responses of men and women in these types of diseases.
Dr. Michael D. Lockshin, Attending Rheumatologist from The Hospital for Special Surgery wrote, “If women are more likely to develop lupus because they produce estrogen, they could be expected to become more seriously ill. But, overall, men and women with lupus experience the disease with the same range of severity.”
In addition, older studies reported in Medscape have shown that estrogen improved skin healing as tested in men and women. In mice, testosterone impaired healing.
One study showed that “systemic HRT significantly accelerates acute wound healing in the elderly, and topical estrogen treatment accelerates the rate of healing in both men and women.”
Another study cited, “In contrast to estrogen, androgens (testosterone) inhibit healing. Castrated mice with reduced systemic testosterone display accelerated healing.”
How exactly estrogen comes into play in wound healing and in autoimmune diseases that have a hormonal component is still uncertain. This effect may be different in different parts of the body.
The study researchers only inferred that estrogen might be involved in ocular inflammation and healing. Many more studies will be needed before estrogen’s role in other immune diseases can be determined.
Sources:
Estrogen Is Responsible for Slow Wound Healing in Women, Study Finds. Science Daily. Retreived April 22, 2012. http://www.sciencedaily.com/releases/2012/04/120402094341.htm
Wang SB et al. FASEB J. 2012 Apr;26(4):1506-16. Epub 2011 Dec 20.
Estrogen negatively regulates epithelial wound healing and protective lipid mediator circuits in the cornea. Abstract: http://www.ncbi.nlm.nih.gov/pubmed/22186873
Hormonal Influences on Wound Healing: Estrogen Accelerates Healing. Medscape Nurses News. Matthew J. Hardman, PhD; Gillian S. Ashcroft, MA, MRCP, PhD
Posted: 12/09/2005; Wounds. 2005;17(11):313-320. © 2005. Retrieved April 22, 2012.
http://www.medscape.com/viewarticle/518427_3
Autoimmune Disease: Does Sex Matter? Hospital for Special Surgery.
Retrieved April 22, 2012.
http://www.hss.edu/conditions_autoimmune-disease-sex.asp
Michele is an R.N. freelance writer with a special interest in woman’s healthcare and quality of care issues. Other articles by Michele are at www.helium.com/users/487540/show_articles
Edited by Jody Smith