Navigation Links
Estrogen fuels autoimmune liver damage
Date:4/30/2013

A life-threatening condition that often requires transplantation and accounts for half of all acute liver failures, autoimmune hepatitis is often precipitated by certain anesthetics and antibiotics. Researchers say these drugs contain tiny molecules called haptens that ever so slightly change normal liver proteins, causing the body to mistake its own liver cells for foreign invaders and to attack them. The phenomenon disproportionately occurs in women, even when they take the same drugs at the same doses as men.

Results of the new study, described in the April issue of the journal PLoS One, reveal that estrogen and a signaling molecule called interleukin-6 collude to form a powerful duo that leads to immune cell misconduct and fuels autoimmune liver damage.

The findings, the research team says, also suggest therapeutic strategies to curb damage in people who develop drug-induced liver inflammation.

"Our study shows that estrogen is not alone in its mischief but working with an accomplice to set off a cascade of events that leads to immune cell dysregulation and culminates in liver damage," says Dolores Njoku, M.D., a pediatric anesthesiologist and critical care expert at Johns Hopkins Children's Center.

In the study, led by Njoku, researchers induced liver inflammation in mice by injecting them with drug-derived haptens. Female mice developed worse liver damage than male mice, and castrated male mice fared worse than their intact brethren, likely due to loss of testosterone and altered estrogen-to-testosterone ratio, the researchers say. Female mice with missing ovaries the chief estrogen-secreting organs suffered milder forms of hepatitis than mice with intact ovaries.

Female mice produced more liver-damaging antibodies and more inflammation-triggering chemicals, specifically the inflammatory molecule interleukin-6, known to fuel autoimmunity. Liver damage was notably milder in female mice whose interleukin-6 receptors were blocked or missing compared with normal female mice. On the other hand, male mice and female mice with missing ovaries had nearly undetectable levels of interleukin-6, while castrated male mice showed simultaneous upticks in both estrogen and interleukin-6.

The research team further zeroed in on a class of cells known as regulatory T cells, whose main function is keeping tabs on other immune cells to ensure they don't turn against the body's own tissues. When researchers compared the number of regulatory T cells present in the spleens of male and female mice, they noticed far fewer regulatory T cells in the spleens of female mice. The spleen, the researchers explain, is the primary residence of mature immune cells.

"Deficiency of regulatory T cells effectively takes the reins off other immune cells, leading to overactive immunity," Njoku says.

In a final, dot-connecting move, the researchers immersed spleen-derived immune cells in estrogen. What they observed proved beyond doubt that estrogen, interleukin and regulatory T cells form a powerful triangle. Estrogen induced the immune cells of female mice to express more interleukin-6, which in turn diminished the expression of inflammation-taming regulatory T cells.

When the researchers injected sick female mice with a booster dose of regulatory T cells, their liver inflammation subsided to levels seen in male mice.

This powerful response, the researchers say, suggests that therapy with regulatory T cells may reduce estrogen-related liver damage in patients with autoimmune hepatitis. Such treatment, however, remains years away from human application.

One reason, the researchers say, is that regulatory T cells maintain the fine equilibrium between overactive and underactive immunity. Because an overactive immune system can lead to autoimmune diseases and an underactive one can promote tumor growth, any therapy with regulatory T cells must be precisely calibrated to avoid tipping this precarious balance.

"We first must figure out where the golden mean lies," Njoku says.


'/>"/>

Contact: Ekaterina Peshva
epeshev1@jhmi.edu
410-502-9433
Johns Hopkins Medicine
Source:Eurekalert

Related medicine news :

1. Estrogen Level in Pregnancy May Affect Breast Cancer Risk in Daughters
2. Estrogen plus progestin use linked with increased breast cancer incidence and mortality
3. Estrogen helps keep joint pain at bay after hysterectomy
4. Maturitas publishes clinical guide on low-dose vaginal estrogens for vaginal atrophy
5. Genetic markers for testosterone and estrogen level regulation identified
6. BUSM researchers identify genetic markers for testosterone, estrogen level regulation
7. Muscular Development Store Affirms Whey Protein Fuels Strong Workouts
8. 1 week and counting: Dont cut the research that fuels the US economy
9. Evidence on abortion figures overestimated in Mexico fuels scientific debate in medical journal
10. Autoimmune disease linked to pregnancy loss, stroke more often than you’d expect
11. Statins have potential to treat an autoimmune clotting disorder called antiphospholipid syndrome
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:2/8/2016)... Los Angeles, CA (PRWEB) , ... February 08, 2016 , ... ... autism conference held annually in this country. The AutismOne 2016 Conference, which is being ... the truth they often won’t hear elsewhere about helpful interventions and causes of chronic ...
(Date:2/7/2016)... ... February 07, 2016 , ... ... MyDecision™ empowers employers and organizations with the tools and information to lower the ... elements to cut the cost of providing employee healthcare benefits by as much ...
(Date:2/6/2016)... ... February 06, 2016 , ... With the FCPX LUT: Summer ... grades to their footage. A LUT is a Lookup Table that contains a mathematical ... color indicated by the table. By manipulating each pixel, LUT's can change each color ...
(Date:2/5/2016)... ... February 05, 2016 , ... Love is in the air at King Kullen! ... assortments and packaging. This staple for Valentine’s Day is a must-have, and can be ... Valentine’s Day, not only are long-stem roses available, but also other flower bouquets, elegantly ...
(Date:2/5/2016)... ... 2016 , ... The event is being held on April 7, 2016 from ... Triumph Over Parkinson’s will fund nearly $100,000 for research for the care and cure ... disease and is the architect of this informative event to raise awareness and funds ...
Breaking Medicine News(10 mins):
(Date:2/4/2016)... , Feb. 4, 2016 Summary Breast ... cancer and the most common cancer in women worldwide, ... disease exceedingly prevalent. The number of women diagnosed with ... but the number of deaths has declined due to ... treatment has been revolutionized in the past four decades, ...
(Date:2/4/2016)... VIEW, Calif., Feb. 4, 2016  Omnicell, Inc. (NASDAQ: ... management solutions to healthcare systems, today announced results for ... --> --> GAAP ... $130.3 million, up $5.1 million or 4.1% from the ... 7.2% from the fourth quarter of 2014. Revenue for ...
(Date:2/4/2016)... 4, 2016 In response to the opioid abuse ... Commissioner for Medical Products and Tobacco, along with other FDA ... agency,s approach to opioid medications. The plan will focus on ... in pain access to effective relief. ... , Re-examine the risk-benefit paradigm for opioids and ensure that ...
Breaking Medicine Technology: