摘要
Objectives: To test the hypothesis that a controlled-release preparation of cysteamine, with fewer daily administrations,would improve the quality of life for patients with cystinosis.Study design: A specifically designed nasoenteric tube was used to administer cysteamine directly into the stomach,small intestine (SI) and colon and serial plasma cysteamine,serum gastrin and leukocyte cystine levels were measured.Results: Eight control subjects (mean age 23.2 years) and 6 subjects with cystinosis (mean age 15.2 years) were studied.Cysteamine absorption (maximum concentration and area under the curve of the concentration-time gradient) was greater from the SI than stomach or cecum (P < 0.01). Leukocyte cystine depletion was greater after delivery of cysteamine into the SI than stomach or cecum; this effect was associated with the plasma cysteamine maximum concentration and area under the curve (P < 0.001 and < 0.02, respectively)-. Gastrin levels were not affected by site of drug delivery and were elevated only in patients with cystinosis with gastrointestinal symptoms. Conclusions: The absorption of cysteamine and the effect of this agent on leukocyte cystine depletion are more profound after SI administration. Enteric-coated cysteamine, targeted for SI release, may require fewer daily dosages. Not all patients with cystinosis require acid-suppression therapy.
Objectives: To test the hypothesis that a controlled-release preparation of cysteamine, with fewer daily administrations,would improve the quality of life for patients with cystinosis.Study design: A specifically designed nasoenteric tube was used to administer cysteamine directly into the stomach,small intestine (SI) and colon and serial plasma cysteamine,serum gastrin and leukocyte cystine levels were measured.Results: Eight control subjects (mean age 23.2 years) and 6 subjects with cystinosis (mean age 15.2 years) were studied.Cysteamine absorption (maximum concentration and area under the curve of the concentration-time gradient) was greater from the SI than stomach or cecum (P < 0.01). Leukocyte cystine depletion was greater after delivery of cysteamine into the SI than stomach or cecum; this effect was associated with the plasma cysteamine maximum concentration and area under the curve (P < 0.001 and < 0.02, respectively)-. Gastrin levels were not affected by site of drug delivery and were elevated only in patients with cystinosis with gastrointestinal symptoms. Conclusions: The absorption of cysteamine and the effect of this agent on leukocyte cystine depletion are more profound after SI administration. Enteric-coated cysteamine, targeted for SI release, may require fewer daily dosages. Not all patients with cystinosis require acid-suppression therapy.
