Journal of Lipid Research, Vol 37, 1766-1775, Copyright © 1996 by Lipid Research, Inc.
Adaptation of cholesterol absorption after proximal resection of porcine small intestine
M Pakarinen, TA Miettinen, J Lauronen, P Kuusanmaki, P Raivio, T Kivisto and J Halttunen
Department of Gastrointestinal Surgery, Helsinki University Central Hospital, Finland.
Cholesterol absorption occurs primarily in the upper small intestine. Our
aim was to assess absorption of cholesterol during ileal adaptation after
proximal small intestinal resection. In vivo absorption and elimination of
cholesterol, plasma cholesterol, cholesterol precursors, and plant sterols
were related to intestinal morphology and transit 4 (n = 5), 8 (n = 5), and
14 (n = 5) weeks after a 75% proximal resection of porcine small intestine,
and compared to preoperative (n = 5) and transected (n = 5) control
animals. Fractional cholesterol absorption, the daily amount of cholesterol
absorbed, plasma cholesterol, and plant sterol to cholesterol proportions
were significantly (P < 0.05 or less) decreased, whereas fecal loss of
cholesterol as neutral steroids, less so as bile acids, plasma cholesterol
precursor proportions, and ileal mass and villus height were significantly
increased (P < 0.05 or less) after 8 weeks of the resection. Cholesterol
absorption efficiency, decreased by the resection, was gradually increased
from 5.4 +/- 2.2 to 26.9 +/- 3.9% during the 14 postoperative weeks (P <
0.0001) simultaneously with a 46% increase in villus height compared with
transection (P < 0.0001), but absorption remained still below control
levels (80.4 +/- 2.5%, P < 0.0001). In resected and control animals,
villus height correlated positively with cholesterol absorption efficiency
(r = 0.85, P < 0.0001; r = 0.76, P = 0.01) and plasma plant sterol
proportions (r = 0.94-0.95, P < 0.0001; r = 0.78-0.85, P < 0.008),
respectively. In conclusion, after massive proximal small bowel resection,
adaptation of intestinal cholesterol absorption efficiency occurs in the
distal ileum closely parlleling villus hypertrophy.