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S Makhija, P-Y von der Weid, J Meddings, PL Beck

GI and Mucosal Inflammation Research Groups, University of Calgary, Calgary, Alberta

We present two patients with intestinal lymphangiectasia. Intestinal lymphangiectasia is rare cause of protein losing enteropathy. Management is often ineffective and generally includes a low fat diet and medium chain triglyceride (MCT) oil. Several medications have also been tried without success. Recently octreotide has been used in a small number of patients with mixed results. It is unclear why octreotide was used in these cases for there have been no studies to date assessing the actions of this agent on lymphatic function.

AIM: Assess the role of octreotide on lymphatic function.

METHODS: To investigate whether octreotide directly affects lymphatic pumping function, we assessed its effect on lymphatic vessels of the ileal portion of the guinea-pigs mesentery. This intra-vital preparation is a well-established model that has been used to characterize physiological and pharmacological properties of lymphatic pumping. The contractile activity of lymphatic vessels was monitored via video microscopy and vessel diameter was analyzed in real time using a video-dimension analyzer. A 5 min control period of contractile activity was recorded before octreotide (Sandostatin, Novartis, Basle, CH) was applied for 4 min, at various concentrations.

RESULTS: Octreotide had no effect on lymphatic vessel pumping activity over a wide range of concentrations (20 nM to 10 µM). Despite the absence of response to octreotide, the same vessels responded to treatments with 5-HT with a decrease in constriction frequency (47.3±10.5% of control) and to application of histamine with an increase in pumping (125.3±20.9% of control). Thus, although pumping of guinea-pig mesenteric lymphatic vessels could be altered by known modulatory agents, it was not affected by octreotide. Of our two clinical cases, one patient was managed with MCT oil with a good response while the second patient failed MCT oil therapy and was then tried empirically on octreotide without clinical response.

CONCLUSION: In a bedside-to-bench approach we could not find any evidence that octreotide enhanced lymphatic function in our animal model nor did the one patient that empirically received octreotide respond to this intervention.

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