Decreased nitric oxide serum level after pituitary adenoma resection.

BACKGROUND: Nitric oxide (NO) is synthesized by the conversion of Arginine (Arg) into the NO and Citrulline (Cit). Although the NO is involved into the pathogenesis of several physiological and pathological processes, the role of NO in pituitary adenomas (PA) progression is not determined. Our purpose was to evaluate the relationship between NO and PA as well as the effect of tumor resection on NO metabolites level in serum. METHODS: The study group consisted of 21 patients with PA, 18 patients with macroadenomas and 3 with microadenomas. Venous blood samples were collected at two time-points; 1) before the surgery and 2) 3-5 days after PA resection. Arg and Cit levels were determined by the automated ion-exchange chromatography with usage of Amino Acids Analyser (AAA 400). Commercially available kit for the evaluation of nitrate/nitrite serum levels was applied for indirect assessment of serum NO level. RESULTS: Significant decrease in NO concentration after the surgery was observed in comparison with the time-point 1. Arg level did not significantly change during the study period. Cit level was ranged below the detection limit of applied method. CONCLUSIONS: The decrease of NO level after the pituitary adenoma resection indicates the relationship between NO synthesis and PA occurrence.

Different patterns of gelatinolytic activity in pituitary macro- and microadenomas.

OBJECTIVE: Gelatinases, Matrix MetalloProteinase(MMP)-2 and MMP-9, belong to zinc-dependent endopeptidases involved in several physiological and pathological processes including inflammation and tumor development. Because the information about the involvement of gelatinases in pituitary adenoma (PA) development are scant, our objective was the analysis of MMP-2 and MMP-9 activity in serum and tumor tissue of PA patients. PATIENTS AND METHODS: Twenty one patients with PA (macroadenoma n=18, microadenoma n=3), qualified to the endoscopic resection of tumors were enrolled. Venous blood samples were collected before the surgery and PA tissue was collected during the surgery. Tissue material was homogenized in a buffer containing 0.1M Tris-HCl pH 7.4 and centrifuged. The supernatant was set to the equal protein content 18µg/sample. Protein level in tissue samples was estimated with Bradford method. MMP-2 and MMP-9 analysis in serum and tissue was performed with gelatin zymography. RESULTS: The proteolytically activated forms of MMPs were not observed in the analyzed sera. Serum activities of MMP-2 and MMP-9 did not statistically differ between patients with micro and macroadenomas. The analysis of material obtained from tissue of microadenomas showed slightly lower activities of both forms of MMP-9 (pro-MMP-9 and MMP-9/lipokalin heterodimer). Simultaneously the increased activity of pro-MMP-2 in comparison to macroadenomas was observed. Although differences observed did not reach statistical significance, only in the case of microadenomas the presence of the active form of MMP-2 (molecular weight 65kDa band) was observed. CONCLUSION: In the course of PA growth the change the biochemical profile of the gelatinolytic activity within the tumor tissue is observed. Initially, the higher activity of MMP-2 in microadenomas and elevated activity of MMP-9 in macroadenomas were detected.

Actylise treatment does not influence nitric oxide metabolites serum level.

BACKGROUND: Nitric oxide (NO) is synthesized by Nitric Oxide Synthases (NOS), the family of enzymes capable to conduct the conversion of Arginine (Arg) into the NO and Citrulline (Cit). Currently, only the administration of recombinant tissue plasminogen activator (rtPA) is recommended for acute ischemic stroke (AIS) treatment. To allow solubility of rtPA, Arg is added as a constituent of the drug. Our purpose was to check the effect of alteplase administration on NO metabolites concentration in the blood. METHODS: Eighteen AIS patients were selected into the study. Nine of them received thrombolytic therapy (rtPA group). The serum samples were obtained at 3 time-points for rtPA group (time-point 0: 1st-4th hour of stroke; time-point 1: immediately after rtPA administration; time-point 3: on day 5-7 from stroke onset). Remaining patients (non-rtPA group) had blood collection at two time-points: time-point 1: 1st-10th hour of stroke and time-point 2: on day 5-7 of stroke. Arg and Cit were determined by the automated ion-exchange chromatography using Amino Acids Analyzer. NO serum level was indirectly evaluated with the usage of commercially available kits that measuring the nitrate/nitrite level. RESULTS: Significant increase of Arg serum level was noticed at time-point 1, directly after the iv thrombolysis in comparison to non-rtPA group. However, the products of the reaction catalyzed by NOS (NO and Cit) did not rise after the thrombolysis. CONCLUSIONS: Current study showed that Arg administration simultaneously with rtPA, as a constituent of Actylise, does not affect serum NO metabolites level.