SUBSTANCE P AND THE PATHOGENESIS OF CRYPTOSPORIDIOSIS IN AIDS

这个子项目是利用由NIH/NCRR资助的中心拨款提供的资源的许多研究子项目之一。子项目和调查员(PI)可能从另一个NIH来源获得了主要资金，因此可能会出现在其他CRISE条目中。列出的机构是针对中心的，而不一定是针对调查员的机构。隐孢子虫病是由原生动物寄生虫微小隐孢子虫引起的，会导致艾滋病患者出现自限性腹泻。目前还没有针对隐孢子虫病的具体预防或治疗方法。因此，迫切需要创新的药物来治疗这种疾病。隐孢子虫感染引起肠道生理改变，如葡萄糖吸收不良、氯离子(CI)分泌增加和上皮屏障破坏，从而导致疾病的发生。为了开发工具来对抗这种机会性病原体，了解参与疾病发病机制的介质是至关重要的。P物质(SP)是一种神经肽和痛觉递质，位于胃肠道。SP可引起人胃肠外植体分泌CI。然而，它在隐孢子虫病中的作用还没有得到充分的研究。分别用RT-PCR、免疫组织化学和ELISA法检测短小衣原体感染前后猕猴空肠组织中P物质及其受体、神经激肽1(NK1)基因和蛋白的表达水平。用Ussing小室技术研究了微小弧菌感染猕猴的生理途径改变，如CI分泌和葡萄糖吸收不良，以及SP在这些改变中的作用。微小隐孢子虫感染后空肠组织中SP和NK1基因和蛋白表达增加，并伴有CI分泌增加和葡萄糖吸收不良。用SP受体拮抗剂体外处理感染猕猴的样本，完全逆转了CI-分泌的增加，纠正了葡萄糖吸收不良。我们的发现增加了使用SP受体拮抗剂治疗与该疾病相关的症状的可能性。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Cryptosporidiosis, caused by the protozoan parasite Cryptosporidium parvum causes self-limited diarrhea in AIDS patients. There is no specific prevention or therapy available for cryptosporidiosis. Therefore, there is an urgent need for innovative drugs to treat this disease. Cryptosporidium infection results in intestinal path physiologic changes such as glucose-malabsorption, increased chloride-ion (CI^-) 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 CI^- secretion in human gastrointestinal-explants. However, its role in cryptosporidiosis has not been fully studied. Jejunal samples from macaques before and after C. parvum infection were assayed for SP and SP receptor, NK1 (neurokinin 1) mRNA and protein levels by RT-PCR and by immunohistochemistry and ELISA, respectively. Path physiologic alterations, such as CI^- secretion and glucose-malabsorption and the role of SP in these alterations was also studied using tissues derived from macaques infected with C. parvum by the Ussing chamber technique. SP and NK1 mRNA and protein expression were increased in jejunal samples following C. parvum infection and were accompanied by increased CI^- secretion and glucose-malabsorption. In vitro treatment of samples obtained from infected macaques with SP receptor antagonist, Emend completely reversed the increase in CI^- secretion and corrected the glucose-malabsorption. Our findings raise the possibility of using SP receptor antagonists for treatment of syptoms associated with this disease.