Featured Research

from universities, journals, and other organizations

How Bad Is Malaria Anemia? It May Depend On Your Genes

Date:
May 11, 2006
Source:
Johns Hopkins Medical Institutions
Summary:
Cell and animal studies conducted jointly by scientists at Johns Hopkins, Yale and other institutions have uncovered at least one important contributor to the severe anemia that kills almost half of the 2 million people worldwide who die each year of malaria. The culprit is a protein cells make in response to inflammation called MIF, which appears to suppress red blood cell production in people whose red blood cells already are infected by malaria parasites.

Cell and animal studies conducted jointly by scientists at Johns Hopkins, Yale and other institutions have uncovered at least one important contributor to the severe anemia that kills almost half of the 2 million people worldwide who die each year of malaria. The culprit is a protein cells make in response to inflammation called MIF, which appears to suppress red blood cell production in people whose red blood cells already are infected by malaria parasites.

Related Articles


The parasite that causes malaria - known as plasmodium - is carried through blood by mosquito bites, and in parts of the world where mosquitoes thrive, millions are infected, most of them by early childhood. Once in the bloodstream, plasmodium invades liver and red blood cells and makes more copies of itself. Eventually, as red cells break and free plasmodium to infect other cells, and as the body's immune system works to kill infected cells, the total number of red blood cells drops, causing anemia.

But not everyone infected with malaria develops severe, lethal anemia. And there are cases where patients who have been cured of infection still develop severe anemia.

This report provides the rationale for a simple, genetic test to sort out which children may be most susceptible to this lethal complication of malarial infection and to identify treatments targeted to them especially, the study's authors suggest.

"This is important because in places where malaria is endemic, drug treatment resources are scarce," says the study's primary author, Michael A. McDevitt, M.D., Ph.D., an assistant professor of medicine and hematology at the Johns Hopkins School of Medicine.

"There are many difficulties with blood transfusion safety and access in Africa, especially in rural areas where most of the malaria-related deaths occur," says McDevitt. "That led us to search for a better way to identify those most at risk and a better way to treat the disease," he says.

The study, published online April 24 in the Journal of Experimental Medicine, adds to a growing amount of evidence that an individual's unique genetic makeup can affect the prevalence and outcome of diseases, in this case the individual risk of malarial anemia.

A number of human proteins, including MIF (which stands for migration inhibitory factor), were long suspected to cause malarial anemia because they are known to reduce red blood cell counts as part of the body's normal response to such inflammatory conditions as rheumatoid arthritis or some cancers.

Using immature blood cell precursors grown in a dish, the research team showed that adding MIF to the cells decreases both the final number and maturity of red blood cells. The researchers believe this effect can lead to anemia.

When infected with plasmodium, mice genetically engineered to lack MIF experience less severe anemia and are more likely to survive. Without MIF around to prevent blood cells from maturing, the mice appear better able to maintain their oxygen carrying capacity and don't lose as much hemoglobin, the protein found in red blood cells responsible for binding to oxygen molecules.

"Demonstrating that MIF clearly contributes to severe anemia suggests new ideas for therapies that can block MIF in malaria patients," says the study's senior author, Richard Bucala, M.D., Ph.D., a professor of medicine at Yale University School of Medicine.

The research team also found different versions of "promoter" DNA sequences next to the MIF gene that control how much MIF protein a cell makes in response to infection. One version of the MIF promoter leads to less MIF protein made, while cells containing another version of the MIF promoter make much more MIF protein. Differences in the MIF promoter also have been linked to the severity of other inflammatory diseases.

The researchers continue to collaborate in an effort to develop drugs that might block MIF and treat severe anemia in malaria patients.

The researchers were funded by the National Institutes of Health, the Office of Research on Minority Health, a Howard University General Clinical Research Center grant, and the Department of Medicine at Johns Hopkins.

Authors on the paper are McDevitt, Ganapathy Shanmugasundaram and Jeffrey Keefer of Johns Hopkins; Jianlin Xie and Christine Metz of the Feinstein Institute for Medical Research; Jason Griffith, Aihua Liu, Courtney McDonald, Lin Leng and Bucala of Yale; Philip Thuma of the Macha Malaria Research Institute in Choma, Zambia, a field unit of the Johns Hopkins Bloomberg School of Public Health; Victor Gordeuk of Howard University; Robert Mitchell of the James Graham Brown Cancer Center; and John David of Harvard School of Public Health.

On the Web: http://www.jem.org/cgi/content/full/jem.2035iti1v1


Story Source:

The above story is based on materials provided by Johns Hopkins Medical Institutions. Note: Materials may be edited for content and length.


Cite This Page:

Johns Hopkins Medical Institutions. "How Bad Is Malaria Anemia? It May Depend On Your Genes." ScienceDaily. ScienceDaily, 11 May 2006. <www.sciencedaily.com/releases/2006/05/060511185749.htm>.
Johns Hopkins Medical Institutions. (2006, May 11). How Bad Is Malaria Anemia? It May Depend On Your Genes. ScienceDaily. Retrieved December 19, 2014 from www.sciencedaily.com/releases/2006/05/060511185749.htm
Johns Hopkins Medical Institutions. "How Bad Is Malaria Anemia? It May Depend On Your Genes." ScienceDaily. www.sciencedaily.com/releases/2006/05/060511185749.htm (accessed December 19, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Friday, December 19, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Kids Die While Under Protective Services

Kids Die While Under Protective Services

AP (Dec. 18, 2014) As part of a six-month investigation of child maltreatment deaths, the AP found that hundreds of deaths from horrific abuse and neglect could have been prevented. AP's Haven Daley reports. (Dec. 18) Video provided by AP
Powered by NewsLook.com
Dads-To-Be Also Experience Hormone Changes During Pregnancy

Dads-To-Be Also Experience Hormone Changes During Pregnancy

Newsy (Dec. 18, 2014) A study from University of Michigan researchers found that expectant fathers see a decrease in testosterone as the baby's birth draws near. Video provided by Newsy
Powered by NewsLook.com
Prenatal Exposure To Pollution Might Increase Autism Risk

Prenatal Exposure To Pollution Might Increase Autism Risk

Newsy (Dec. 18, 2014) Harvard researchers found children whose mothers were exposed to high pollution levels in the third trimester were twice as likely to develop autism. Video provided by Newsy
Powered by NewsLook.com
UN: Up to One Million Facing Hunger in Ebola-Hit Countries

UN: Up to One Million Facing Hunger in Ebola-Hit Countries

AFP (Dec. 17, 2014) Border closures, quarantines and crop losses in West African nations battling the Ebola virus could lead to as many as one million people going hungry, UN food agencies said on Wednesday. Duration: 00:52 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins