SOMATOSTATIN RECEPTORS SSTR2 AND SSTR5 ARE EXPRESSED IN THE HUMAN THORACIC DUCT

Abstract

Somatostatin and its analog octreotidehave been used successfully to treatpostoperative chylothorax, and it has beenshown that octreotide binds with high affinityto somatostatin receptor (SSTR) subtypes 2and 5. Therefore, we investigated expressionof SSTR2 and SSTR5 in the human thoracicduct by immunohistochemistry. Normal ratpancreas was used as a positive control forantibodies against SSTR2 and SSTR5, andFactor VIII-related antigen, SMA, actin,elastin, or collagen type II, III, IV or Vantibodies were used to identify cell types andstructures within the human thoracic duct.The antibodies against SSTR2 and SSTR5worked well and yielded positive staining incontrol rat islets. In the human thoracic duct,SSTR2 was present in smooth muscle cellsand some scattered structures which werestained by antibodies against Factor VIIIrelatedantigen, SMA, actin, elastin orcollagen type II, III, IV or V. SSTR5 was alsopresent in smooth muscle cells. The presenceof SSTR2 and SSTR5 in the human thoracicduct sheds light on the mechanism of somatostatinand octreotide use in the successfultreatment of chylothorax and offers newmolecular pathways to explore for potentialfuture therapies.