PURPOSE: The secretion mechanism of peptide YY involves systemic factors, such as humoral and neural stimuli, and local factors, such as intestinal peristalsis and intraluminal nutrients. This study was designed to su...PURPOSE: The secretion mechanism of peptide YY involves systemic factors, such as humoral and neural stimuli, and local factors, such as intestinal peristalsis and intraluminal nutrients. This study was designed to survey the impact of local stimuli on the secretion of peptide YY under circumstances in which systemic stimuli are identical. METHODS: Ileostomies were repaired within three months in a short-term group (14 patients)- and after six months in a long-term group (14 patients). Mucosal peptide YY concentrations and cytomorphologic change, such as villus height, crypt depth, mucosal thickness, and villus index, were compared between proximal functioning ileum and a distal nonfunctioning ileal loop during ileostomy repair. In a control group of patients undergoing right hemicolectomy (21 cases), the normal distribution of pept-ide YY was measured in the mucosa throughout the distal ileum. RESULTS: The peak of peptide YY concentration in the terminal ileum was 307.4 ± 21 pmol/g, 25cm from the ileocecal valve, with lower levels both proximally and distally. The mucosa of the functioning ileum in the short-term group showed hypertrophy, but had returned to preoperative levels in the long-term group. The nonfunctioning mucosa in both groups underwent atrophic changes. The mucosal peptide YY content in functioning ileum in the short-term group was higher than that of distal nonfunctioning mucosa (363.9 ± 25.5 pmol/g vs. 284.1 ± 13 pmol/g, P < 0.05), suggesting adaptive upregulation. The increments of mucosal peptide YY content in this short-term group compared with the control group were 45.6 and 4.7 percent in the proximal and distal segments, respectively. In the long-term group, proximal and distal mucosal peptide YY were similar (256.6 ± 31.9 pmol/g vs. 254.9 ± 27.1 pmol/g, P > 0.05), and there was no increment in either (1.3 vs. 4.4 percent, P > 0.05). CONCLUSIONS: The peak concentrations of PYY in the ileal mucosa are found 20 to 25 cm proximal to the ileocecal valve. In the short-term response of ileostomy, local stimulatory factors play a major role in the adaptation of mucosal PYY. In the defunctioned bowel without luminal stimulation, systemic stimulation was important for maintenance of mucosal PYY.展开更多
Proctocolectomy modifies the enterohepatic circulation and activity of bacteri al enzymes depending on the structure of the stoma and function of the terminal ileum. We evaluated in our comparative study effects of di...Proctocolectomy modifies the enterohepatic circulation and activity of bacteri al enzymes depending on the structure of the stoma and function of the terminal ileum. We evaluated in our comparative study effects of different colectomy cons tructions on cholesterol metabolism. Levels of lipoprotein cholesterol and trigl ycerides, noncholesterol sterols, and squalene in serum, fecal fat, and bile aci ds, cholesterol absorption efficiency, and cholesterol metabolism by sterol bala nce technique were analyzed in human subjects with ileal pouch-anal anastomosis (n=34), conventional ileostomy (n =8), ileorectostomy (n =6), and controls (n = 29). Malabsorption of bile acids, but not of fat, and low serum levels of total and low-density lipoprotein cholesterol, but high levels of high-density lipop rotein cholesterol and increased cholesterol synthesis were evident in the colec tomy groups. In contrast to the ileorectostomy group, expressing high absorption and biliary secretion of cholesterol, a low cholesterol absorption percentage a ccompanied by elevated serum proportions of cholesterol precursor sterols and ph ytosterols characterized the ileal pouch-anal anastomosis and conventional ileo stomy groups. After colectomy, fecal excretion of secondary bile acids was low, wher eas relative proportions of identifiable bile acids remained the same in each st udy group. Low serum levels of total and lowdensity lipoprotein cholesterol of c olectomized subjects may decrease the risk of premature atherosclerosis. The fav orable serum lipid profile was due to enhanced fecal loss of cholesterol as bile acids despite abnormally high cholesterol synthesis. Ileal dysfunction probably diminished cholesterol absorption in subjects with ileal pouch-anal anastomosi s and conventional ileostomy, with no explanation for those with ileorectostomy with no clinical gastrointestinal dysfunction. Relative synthesis of identifiabl e primary bile acids remained unchanged postoperatively, but formation of second ary bile acids was weak due to scarce bacterial flora.展开更多
文摘PURPOSE: The secretion mechanism of peptide YY involves systemic factors, such as humoral and neural stimuli, and local factors, such as intestinal peristalsis and intraluminal nutrients. This study was designed to survey the impact of local stimuli on the secretion of peptide YY under circumstances in which systemic stimuli are identical. METHODS: Ileostomies were repaired within three months in a short-term group (14 patients)- and after six months in a long-term group (14 patients). Mucosal peptide YY concentrations and cytomorphologic change, such as villus height, crypt depth, mucosal thickness, and villus index, were compared between proximal functioning ileum and a distal nonfunctioning ileal loop during ileostomy repair. In a control group of patients undergoing right hemicolectomy (21 cases), the normal distribution of pept-ide YY was measured in the mucosa throughout the distal ileum. RESULTS: The peak of peptide YY concentration in the terminal ileum was 307.4 ± 21 pmol/g, 25cm from the ileocecal valve, with lower levels both proximally and distally. The mucosa of the functioning ileum in the short-term group showed hypertrophy, but had returned to preoperative levels in the long-term group. The nonfunctioning mucosa in both groups underwent atrophic changes. The mucosal peptide YY content in functioning ileum in the short-term group was higher than that of distal nonfunctioning mucosa (363.9 ± 25.5 pmol/g vs. 284.1 ± 13 pmol/g, P < 0.05), suggesting adaptive upregulation. The increments of mucosal peptide YY content in this short-term group compared with the control group were 45.6 and 4.7 percent in the proximal and distal segments, respectively. In the long-term group, proximal and distal mucosal peptide YY were similar (256.6 ± 31.9 pmol/g vs. 254.9 ± 27.1 pmol/g, P > 0.05), and there was no increment in either (1.3 vs. 4.4 percent, P > 0.05). CONCLUSIONS: The peak concentrations of PYY in the ileal mucosa are found 20 to 25 cm proximal to the ileocecal valve. In the short-term response of ileostomy, local stimulatory factors play a major role in the adaptation of mucosal PYY. In the defunctioned bowel without luminal stimulation, systemic stimulation was important for maintenance of mucosal PYY.
文摘Proctocolectomy modifies the enterohepatic circulation and activity of bacteri al enzymes depending on the structure of the stoma and function of the terminal ileum. We evaluated in our comparative study effects of different colectomy cons tructions on cholesterol metabolism. Levels of lipoprotein cholesterol and trigl ycerides, noncholesterol sterols, and squalene in serum, fecal fat, and bile aci ds, cholesterol absorption efficiency, and cholesterol metabolism by sterol bala nce technique were analyzed in human subjects with ileal pouch-anal anastomosis (n=34), conventional ileostomy (n =8), ileorectostomy (n =6), and controls (n = 29). Malabsorption of bile acids, but not of fat, and low serum levels of total and low-density lipoprotein cholesterol, but high levels of high-density lipop rotein cholesterol and increased cholesterol synthesis were evident in the colec tomy groups. In contrast to the ileorectostomy group, expressing high absorption and biliary secretion of cholesterol, a low cholesterol absorption percentage a ccompanied by elevated serum proportions of cholesterol precursor sterols and ph ytosterols characterized the ileal pouch-anal anastomosis and conventional ileo stomy groups. After colectomy, fecal excretion of secondary bile acids was low, wher eas relative proportions of identifiable bile acids remained the same in each st udy group. Low serum levels of total and lowdensity lipoprotein cholesterol of c olectomized subjects may decrease the risk of premature atherosclerosis. The fav orable serum lipid profile was due to enhanced fecal loss of cholesterol as bile acids despite abnormally high cholesterol synthesis. Ileal dysfunction probably diminished cholesterol absorption in subjects with ileal pouch-anal anastomosi s and conventional ileostomy, with no explanation for those with ileorectostomy with no clinical gastrointestinal dysfunction. Relative synthesis of identifiabl e primary bile acids remained unchanged postoperatively, but formation of second ary bile acids was weak due to scarce bacterial flora.
