This Article Full Text Full Text (PDF) Other Versions of this Article: IAI.01738-05v1 75/3/1137    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Hernandez, J. Articles by Robinson, P. Search for Related Content PubMed PubMed Citation Articles by Hernandez, J. Articles by Robinson, P.

Substance P Is Responsible for Physiological Alterations Such as Increased Chloride Ion Secretion and Glucose Malabsorption in Cryptosporidiosis

Department of Medicine, Section of Infectious Diseases,¹ Department of Pathology, Baylor College of Medicine, One Baylor Plaza, Rm. 535EB, Houston, Texas 77030,⁵ Tulane National Primate Research Center, Division of Microbiology and Immunology, 18703 Three Rivers Road, Covington, Louisiana 70433,² Division of Gastroenterology,³ Department of Public Health and Family Medicine, Tufts New England Medical Center, 750 Washington St., Box 233, Boston, Massachusetts 02111⁴

Received 25 October 2005/ Returned for modification 8 January 2006/ Accepted 3 December 2006

Cryptosporidiosis, caused by the protozoan parasite Cryptosporidium, causes self-limited diarrhea in immunocompetent hosts and severe life-threatening diarrhea in AIDS patients. Highly active antiretroviral therapy has been used to effectively treat cryptosporiosis in some but not all AIDS patients. Therefore, there is an urgent need for innovative drugs to treat this disease. Cryptosporidium infection results in intestinal pathophysiological changes such as glucose malabsorption, increased chloride ion (Cl^–) secretion, and epithelial barrier disruption, leading to disease pathogenesis. In order to develop tools to combat this opportunistic pathogen, it is vital to understand mediators involved in disease pathogenesis. Substance P (SP), a neuropeptide and pain transmitter, is located in the gastrointestinal tract. SP can cause Cl^– secretion in human gastrointestinal explants. However, its role in cryptosporidiosis has not been fully studied. Jejunal samples from macaques before and after Cryptosporidium parvum infection were assayed for SP and SP receptor mRNA and protein levels by reverse transcription-PCR and by immunohistochemistry and enzyme-linked immunosorbent assay, respectively. The role of SP in pathophysiological alterations, such as Cl^– secretion and glucose malabsorption, was studied using tissues derived from macaques infected with C. parvum by the Ussing chamber technique. SP and SP receptor mRNA and protein expression levels were increased in jejunal samples following C. parvum infection and were accompanied by increased basal ion secretion and glucose malabsorption. In vitro treatment of samples obtained from infected macaques with the SP receptor antagonist aprepitant (Emend; Merck, Whitehouse Station, NJ) completely reversed the increase in basal ion secretion and corrected the glucose malabsorption. Our findings raise the possibility of using SP receptor antagonists for the treatment of symptoms associated with cryptosporidiosis.

Published ahead of print on 11 December 2006.

Editor: J. F. Urban, Jr.

This article has been cited by other articles:

• Pantenburg, B., Dann, S. M., Wang, H.-C., Robinson, P., Castellanos-Gonzalez, A., Lewis, D. E., White, A. C. Jr. (2008). Intestinal Immune Response to Human Cryptosporidium sp. Infection. Infect. Immun. 76: 23-29 [Full Text]