Featured Research

from universities, journals, and other organizations

Protein offers new clue to cause and treatment for kidney disease

Date:
December 17, 2010
Source:
University of Alabama at Birmingham
Summary:
Researchers have pinpointed a protein that compromises the kidney's filtering ability, causing nephrotic syndrome, and demonstrated that a naturally occurring precursor of an acid in the body offers potential for treating some forms of the condition.

University of Alabama at Birmingham researchers have pinpointed a protein that compromises the kidney's filtering ability, causing nephrotic syndrome, and demonstrated that a naturally occurring precursor of an acid in the body offers potential for treating some forms of the condition.

The research was published online Dec. 12 in Nature Medicine.

"This is a major breakthrough in understanding the development and treatment of kidney disease associated with proteinuria, the leakage of protein in the urine," said the study's lead author Sumant Singh Chugh, M.D., associate professor of medicine in the UAB Division of Nephrology.

Nephrotic syndrome is characterized by the presence of excessive protein in the urine, low blood-protein levels, high cholesterol, high triglycerides and swelling. Common causes include diabetic nephropathy, minimal change disease, focal and segmental glomerulosclerosis and membranous nephropathy. It also can be caused by infections, certain drugs, cancer, genetic disorders, immune disorders or diseases that affect multiple body systems including lupus, multiple myeloma and amyloidosis.

Chugh said his research team, studying transgenic rats, discovered that in some forms of nephrotic syndrome, a protein called Angiopoietin-like 4 is over-produced in specialized cells called podocytes. Podocytes are found in the glomerular filter, which cleans the blood to produce urine. As a result of the over-production, the efficiency of this filter is compromised, resulting in the loss of blood proteins in the urine. When this dysfunction is severe, it causes nephrotic syndrome.

Chugh said the researchers also determined that the Angiopoietin-like 4 protein lacks the attachment of adequate amounts of sialic acid, a modified carbohydrate that affects the protein's adhesive properties. By feeding sialic acid precursor ManNAc to transgenic rats that over-produce Angiopoietin-like 4 in podocytes, the researchers were able to increase the amount of protein-bound sialic acid, and reduce the amount of protein leakage into the urine by more than 40 percent.

"These findings, at present, most directly relate to minimal change disease, a form of nephrotic syndrome commonly seen in children, but are also likely to be relevant to common causes of proteinuria and nephrotic syndrome in adults, including those with diabetes," Chugh said.

He added that this study is important because traditional forms of therapy, which include the use of glucocorticoids, for example prednisone, and other immunosuppressive drugs can have significant toxicity, especially after prolonged use or repeated cycles of treatment. However, sialic acid and ManNAc are naturally occurring substances in the body, and toxicity is likely to be limited. The investigators, he said, believe that relatively small doses of the sialic acid may be effective for nephrotic syndrome, since, unlike most other cells in the body, the target cell in the kidney does not divide under most conditions and is likely to accumulate these compounds even at low doses.

"The major known toxicity of sialic acid therapy observed by other investigators in a mouse model of the human muscle disease, hereditary inclusion body myopathy, was the development of ovarian cysts at very high doses," Chugh said. "These doses are approximately 20-fold higher than those used to reduce proteinuria in rats in the current study; knowing that, we believe sialic acid repletion has potential in the future treatment of Minimal Change Disease and some other forms of nephrotic syndrome."


Story Source:

The above story is based on materials provided by University of Alabama at Birmingham. Note: Materials may be edited for content and length.


Journal Reference:

  1. Lionel C Clement, Carmen Avila-Casado, Camille Macé, Elizabeth Soria, Winston W Bakker, Sander Kersten & Sumant S Chugh. Podocyte-secreted angiopoietin-like-4 mediates proteinuria in glucocorticoid-sensitive nephrotic syndrome. Nature Medicine, 12 December 2010 DOI: 10.1038/nm.2261

Cite This Page:

University of Alabama at Birmingham. "Protein offers new clue to cause and treatment for kidney disease." ScienceDaily. ScienceDaily, 17 December 2010. <www.sciencedaily.com/releases/2010/12/101212145233.htm>.
University of Alabama at Birmingham. (2010, December 17). Protein offers new clue to cause and treatment for kidney disease. ScienceDaily. Retrieved April 16, 2014 from www.sciencedaily.com/releases/2010/12/101212145233.htm
University of Alabama at Birmingham. "Protein offers new clue to cause and treatment for kidney disease." ScienceDaily. www.sciencedaily.com/releases/2010/12/101212145233.htm (accessed April 16, 2014).

Share This



More Health & Medicine News

Wednesday, April 16, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Could Even Casual Marijuana Use Alter Your Brain?

Could Even Casual Marijuana Use Alter Your Brain?

Newsy (Apr. 16, 2014) — A new study conducted by researchers at Northwestern and Harvard suggests even casual marijuana use can alter your brain. Video provided by Newsy
Powered by NewsLook.com
Formerly Conjoined Twins Released From Dallas Hospital

Formerly Conjoined Twins Released From Dallas Hospital

Newsy (Apr. 16, 2014) — Conjoined twins Emmett and Owen Ezell were separated by doctors in August. Now, nearly nine months later, they're being released from the hospital. Video provided by Newsy
Powered by NewsLook.com
Ebola Outbreak Now Linked To 121 Deaths

Ebola Outbreak Now Linked To 121 Deaths

Newsy (Apr. 15, 2014) — The ebola virus outbreak in West Africa is now linked to 121 deaths. Health officials fear the virus will continue to spread in urban areas. Video provided by Newsy
Powered by NewsLook.com
Cognitive Function: Is It All Downhill From Age 24?

Cognitive Function: Is It All Downhill From Age 24?

Newsy (Apr. 15, 2014) — A new study out of Canada says cognitive motor performance begins deteriorating around age 24. Video provided by Newsy
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:
from the past week

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