Expression of extracellular matrix-proteins in perisellar connective tissue and dura mater

Objectives: To describe the pattern of expression of matrix proteins (ECM) in perisellar connective tissue as possible targets for proteinases derived from invasive pituitary adenomas.

Methods: Post mortem specimens obtained from 10 individuals without endocrinological disease (4 fem., 6 mal., mean age 70yrs, range 47–81yrs): anterior pituitary boundary n=9, diaphragma sellae n=2, medial wall of the cavernous sinus (CS) n=19, lateral wall of the CS n=20, convexity dura n=9, tentorial dura n=10, temporal fascia n=10, intracavernous ICA n=14, internal jugular vein n=8. The material was formalin-fixed and embedded in paraffine. Routine HE-staining and immunohistochemical detection using commercially available antibodies against collagen I, II, III, and IV, as well as tenascin, fibronectin, elastin, laminin, and vitronectin was performed using the streptavidine-biotin method.

Results: Collagen I and III were strongly, collagen II weakly, and collagen IV moderately expressed in the medial and lateral as well as anterior boundaries of the sella and the CS. Fibronectin was strongly expressed in the edge of the sellar compartment and dura mater. Tenascin and vitronectin showed moderate expression in these structures, whereas expression of elastin and laminin was weak or absent. In 6 of 9 specimen derived from the anterior boundary of the sella (pituitary capsule) two different layers could be detected by the expression of collagen I (n=1), collagen II (n=1), collagen III (n=2), collagen IV (n=3), tenascin (n=4), fibronectin (n=3), vitronectin (n=1), and elastin (n=1). In 11 of 19 specimen derived from the lateral boundary of the sella (medial wall of the CS) two different layers could be detected by the expression of collagen I (n=5), collagen II (n=3), collagen III (n=3), collagen IV (n=4), tenascin (n=8), fibronectin (n=4), vitronectin (n=7), and elastin (n=1).

Conclusion: Our observations indicate that the pituitary boundary may be composed as a single or a double layer, and it may in part be differentiated from dura by expression pattern of ECM proteins.