Featured Research

from universities, journals, and other organizations

Famous French Artist's Genetic Disorder Sheds Light On Enzyme's Role In Bone Metabolism

Date:
November 6, 2008
Source:
Wiley-Blackwell
Summary:
Pycnodysostosis, a condition from which the painter Henri de Toulouse-Lautrec suffered, is a genetic disease characterized by short stature. This rare disease, surprisingly, provides a window into how joints are destroyed by arthritis.

Pycnodysostosis, a condition from which the painter Henri de Toulouse-Lautrec suffered, is a genetic disease characterized by short stature. This rare disease, surprisingly, provides a window into how joints are destroyed by arthritis. It is caused by deficiency of an enzyme known as cathepsin K which hampers osteoclasts (the cells that break down bone in bone modeling and repair), leading to poor bone resorption and dense, brittle bones.

Cathepsin K's role in bone metabolism has largely been studied using mouse models, but a new study examines the enzyme's role in bone resorption in a human patient and shows that it is not required to break down bone. The study was published in the November issue of Arthritis & Rheumatism.

Led by Professor Yrjö T. Konttinen of Helsinki University Central Hospital in Helskinki, Finland , the study involved a 55-year-old female patient with pycnodysostosis who also developed psoriatic arthritis. Since the patient lacked cathepsin K due to her condition, researchers hypothesized that this would protect her from the bone erosions in the hands and feet normally seen in psoriatic arthritis. However, she did in fact develop extensive erosions and destructive bone changes in her hands. Blood analysis was conducted to examine the proteinases (enzymes that break down proteins) responsible for bone degradation as well as the cellular mechanisms of bone resorption.

The analyses showed that the osteoclasts formed by the patient lacked cathepsin K, which was expected. Surprisingly, however, this deficiency did not prevent cells from resorbing bone, although the resorption was abnormal. In bone resorption, osteoclasts attach to the bone and dissolve bone mineral in the matrix, a process that appears to proceed normally even in pycnodysostosis. In a second step, known as collagenolysis, peptide bonds in the collagen of the demineralized bone matrix are broken down. The authors expected that this step would be defective in the cells of a patient who lacked cathepsin K, but instead found that it was not, since the patient's osteoclasts showed evidence of bone resorption.

"The results of our study indicate that, against the dogma, cathepsin K is not necessary for osteoclast-mediated bone resorption," the authors state. "The present results and some very recent findings suggest that even total inhibition of cathepsin K does not protect against pathologic bone destruction in arthritis."

This indicates that other proteinases may play a role in bone collagen destruction when cathepsin K is not present. The authors conclude: "These findings may be pertinent to our understanding of the functions of cathepsin K inhibitors, which are currently being developed as drugs to treat metabolic bone diseases.


Story Source:

The above story is based on materials provided by Wiley-Blackwell. Note: Materials may be edited for content and length.


Journal Reference:

  1. Ainola et al. Erosive arthritis in a patient with pycnodysostosis: An experiment of nature. Arthritis & Rheumatism, 2008; 58 (11): 3394 DOI: 10.1002/art.23996

Cite This Page:

Wiley-Blackwell. "Famous French Artist's Genetic Disorder Sheds Light On Enzyme's Role In Bone Metabolism." ScienceDaily. ScienceDaily, 6 November 2008. <www.sciencedaily.com/releases/2008/11/081104132911.htm>.
Wiley-Blackwell. (2008, November 6). Famous French Artist's Genetic Disorder Sheds Light On Enzyme's Role In Bone Metabolism. ScienceDaily. Retrieved October 21, 2014 from www.sciencedaily.com/releases/2008/11/081104132911.htm
Wiley-Blackwell. "Famous French Artist's Genetic Disorder Sheds Light On Enzyme's Role In Bone Metabolism." ScienceDaily. www.sciencedaily.com/releases/2008/11/081104132911.htm (accessed October 21, 2014).

Share This



More Health & Medicine News

Tuesday, October 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

CDC Revamps Ebola Guidelines After Criticism

CDC Revamps Ebola Guidelines After Criticism

Newsy (Oct. 21, 2014) — The Centers for Disease Control and Prevention have issued new protocols for healthcare workers interacting with Ebola patients. Video provided by Newsy
Powered by NewsLook.com
WHO: Ebola Vaccine Trials to Start a in January

WHO: Ebola Vaccine Trials to Start a in January

AP (Oct. 21, 2014) — Tens of thousands of doses of experimental Ebola vaccines could be available for "real-world" testing in West Africa as soon as January as long as they are deemed safe in soon to start trials, the World Health Organization said Tuesday. (Oct. 21) Video provided by AP
Powered by NewsLook.com
First-Of-Its-Kind Treatment Gives Man Ability To Walk Again

First-Of-Its-Kind Treatment Gives Man Ability To Walk Again

Newsy (Oct. 21, 2014) — A medical team has for the first time given a man the ability to walk again after transplanting cells from his brain onto his severed spinal cord. Video provided by Newsy
Powered by NewsLook.com
CDC Issues New Ebola Guidelines for Health Workers

CDC Issues New Ebola Guidelines for Health Workers

Reuters - US Online Video (Oct. 21, 2014) — The U.S. Centers for Disease Control and Prevention has set up new guidelines for health workers taking care of patients infected with Ebola. Linda So reports. Video provided by Reuters
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