Glycosaminoglycan polymerization may enable osmotically inactive Na+ storage in the skin

• Published in: American journal of physiology. Heart and circulatory physiology Vol. 287; no. 1; pp. H203 - H208
• Main Authors: Titze, Jens, Shakibaei, Mehdi, Schafflhuber, Markus, Schulze-Tanzil, Gundula, Porst, Markus, Schwind, Karl H, Dietsch, Peter, Hilgers, Karl F
• Format: Journal Article
• Language: English
• Published: United States 01.07.2004
• Subjects: Animals; Enzymes - metabolism; Extracellular Matrix Proteins - metabolism; Female; Glycosaminoglycans - metabolism; In Vitro Techniques; Osmosis; Polymers - metabolism; Rats; Rats, Sprague-Dawley; Skin - metabolism; Sodium - metabolism
• ISSN: 0363-6135; 1522-1539
• DOI: 10.1152/ajpheart.01237.2003

1 Department of Medicine IV, Friedrich-Alexander-University Erlangen-Nürnberg, D-90471 Nürnberg; Departments of 2 Anatomy and 4 Biochemistry, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, D-14195 Berlin; and 3 Department of Chemistry and Physics, Federal Center for Meat Research, D-95326 Kulmbach, Germany Submitted 29 December 2003 ; accepted in final form 13 February 2004 Osmotically inactive skin Na + storage is characterized by Na + accumulation without water accumulation in the skin. Negatively charged glycosaminoglycans (GAGs) may be important in skin Na + storage. We investigated changes in skin GAG content and key enzymes of GAG chain polymerization during osmotically inactive skin Na + storage. Female Sprague-Dawley rats were fed a 0.1% or 8% NaCl diet for 8 wk. Skin GAG content was measured by Western blot analysis. mRNA content of key dermatan sulfate polymerization enzymes was measured by real-time PCR. The Na + concentration in skin was determined by dry ashing. Skin Na + concentration during osmotically inactive Na + storage was 180–190 mmol/l. Increasing skin Na + coincided with increasing GAG content in cartilage and skin. Dietary NaCl loading coincided with increased chondroitin synthase mRNA content in the skin, whereas xylosyl transferase, biglycan, and decorin content were unchanged. We conclude that osmotically inactive skin Na + storage is an active process characterized by an increased GAG content in the reservoir tissue. Inhibition or disinhibition of GAG chain polymerization may regulate osmotically inactive Na + storage. hypertension; extracellular matrix; chondroitin synthase; elongation enzymes Address for reprint requests and other correspondence: J. Titze, Nephrologische Forschungslaboratorien Medizinische Klinik IV, Loschgestrasse 8, D-91054 Erlangen, Germany (E-mail: jus.titze{at}t-online.de ).