Gastric emptying is a complex and highly coordinated process that remains poorly understood. Several nutrient stimulated neuro-hormonal signals emanating from the gastro-duodenal control gastric emptying. Since we lack the tools to measure in-vivo gastric emptying James Brasseur, a bio-engineer, at the university of Pennsylvania, developed a computer simulation model of the stomach. Using this model, Brasseur et al were able to numerically calculate intra-gastric fluid motions. In 2006, they published an interesting study, in the journal of Biomechanics, titled “A Stomach Road or Magenstrasse for Gastric Emptying”. In this study, Brasseur demonstrates the existence of early post-prandial rapid emptying. The emptying pattern occurs along the lesser curvature and channels food particles from the fundus into the duodenum before any significant digestion has occurred. The researchers found that gastric fundus contractions in coordination with gastric antrum contractions results in Magenstrasse emptying pattern.
Why does the Magenstrasse exist? The authors of this interesting article explain that a “spot of highly concentrated lipid or glucose in liquid or semi-solid form… rather than waiting patiently in the fundus while the antrum and corpus empties… moves rapidly along the Magenstrasse, bypassing most of the fundus, corpus and antrum, and enters the bowels rapidly in highly concentrated form and leaving behind 77% of gastric content”. This sounds like a Roux-en-Y gastric bypass procedure or sleeve gastrectomy mechanism of action. For Brasseur el al, however, the only potential usage of the Magenstrasse is rapid drug delivery into the intestines. In fact, in 2006, the mechanism of action of bariatric surgery was still unknown. Accelerated gastric emptying and dumping to stimulate neuro-endocrine hormones like GLP-1 were not described at that time.
In my opinion, dysfunction in the Magenstrasse gastric emptying results in diseases like obesity, type 2 diabetes, gastroparesis and GERD. Weight loss surgery in the form of gastric bypass and sleeve gastrectomy restores the dumping function of the Magenstrasse. The Magenstrasse emptying pattern is crucial to maintaining healthy gut to food interaction. Brasseur el al have found that “The strength of antral motility relative to fundus-induced contractions affects the extent and density of the Magenstrasse”. The coordination of contractile waves between gastric fundus, where food is received, and gastric antrum, where food is ground and mixed, determines the magnitude of the Magenstrasse. Surgical manipulation of the gastric fundus in the form of sleeve gastrectomy seems to restore the Magenstrasse emptying leading to resolution of obesity and diabetes.
Gastric fundus invagination or sleeve gastrotomy brings the gastric fundus in close proximity to the antrum. It would be interesting to apply Brasseur’s mathematical gastric model to study the effect of sleeve gastrotomy on fundic and antral contractions and their effect on the Magenstrasse. I predict that gastric fundus invagination restores the Magenstrasse leading to weight loss, diabetes resolution and possibly curing gastroparesis similar to sleeve gastrectomy.