Substance P is responsible for physiological alterations such as increased chloride ion secretion and glucose malabsorption in cryptosporidiosis

Julio Hernandez, Andrew Lackner, Pyone Aye, Kakali Mukherjee, David J. Tweardy, Mary Ann Mastrangelo, Joel Weinstock, Jeffrey Griffiths, Melinda D'Souza, Shantu Dixit, Prema Robinson

Research output: Contribution to journalArticlepeer-review

26 Scopus citations

Abstract

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.

Original languageEnglish (US)
Pages (from-to)1137-1143
Number of pages7
JournalInfection and Immunity
Volume75
Issue number3
DOIs
StatePublished - Mar 2007

ASJC Scopus subject areas

  • Parasitology
  • Microbiology
  • Immunology
  • Infectious Diseases

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