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Open access

Jukka Koffert, Henri Honka, Jarmo Teuho, Saila Kauhanen, Saija Hurme, Riitta Parkkola, Vesa Oikonen, Andrea Mari, Andreas Lindqvist, Nils Wierup, Leif Groop and Pirjo Nuutila

Objective

Meal ingestion is followed by a redistribution of blood flow (BF) within the splanchnic region contributing to nutrient absorption, insulin secretion and glucose disposal, but factors regulating this phenomenon in humans are poorly known. The aim of the present study was to evaluate the organ-specific changes in BF during a mixed-meal and incretin infusions.

Design

A non-randomized intervention study of 10 healthy adults to study splanchnic BF regulation was performed.

Methods

Effects of glucose-dependent insulinotrophic polypeptide (GIP) and glucagon-like peptide 1 (GLP-1) infusions and mixed-meal were tested in 10 healthy, glucose tolerant subjects using PET-MRI multimodal imaging technology. Intestinal and pancreatic BF and blood volume (BV) were measured with 15O-water and 15O-carbon monoxide, respectively.

Results

Ingestion of a mixed-meal led to an increase in pancreatic and jejunal BF, whereas duodenal BF was unchanged. Infusion of GIP and GLP-1 reduced BF in the pancreas. However, GIP infusion doubled blood flow in the jejunum with no effect of GLP-1.

Conclusion

Together, our data suggest that meal ingestion leads to increases in pancreatic BF accompanied by a GIP-mediated increase in jejunal but not duodenal blood flow.

Open access

Henri Honka, Jukka Koffert, Saila Kauhanen, Nobuyuki Kudomi, Saija Hurme, Andrea Mari, Andreas Lindqvist, Nils Wierup, Riitta Parkkola, Leif Groop and Pirjo Nuutila

Aims/hypothesis

The mechanisms for improved glycemic control after bariatric surgery in subjects with type 2 diabetes (T2D) are not fully known. We hypothesized that dynamic hepatic blood responses to a mixed-meal are changed after bariatric surgery in parallel with an improvement in glucose tolerance.

Methods

A total of ten morbidly obese subjects with T2D were recruited to receive a mixed-meal and a glucose-dependent insulinotropic polypeptide (GIP) infusion before and early after (within a median of less than three months) bariatric surgery, and hepatic blood flow and volume (HBV) were measured repeatedly with combined positron emission tomography/MRI. Ten lean non-diabetic individuals served as controls.

Results

Bariatric surgery leads to a significant decrease in weight, accompanied with an improved β-cell function and glucagon-like peptide 1 (GLP-1) secretion, and a reduction in liver volume. Blood flow in portal vein (PV) was increased by 1.65-fold (P = 0.026) in response to a mixed-meal in subjects after surgery, while HBV decreased in all groups (P < 0.001). When the effect of GIP infusion was tested separately, no change in hepatic arterial and PV flow was observed, but HBV decreased as seen during the mixed-meal test.

Conclusions/interpretation

Early after bariatric surgery, PV flow response to a mixed-meal is augmented, improving digestion and nutrient absorption. GIP influences the post-prandial reduction in HBV thereby diverting blood to the extrahepatic sites.