Immunoreactive endothelin in nodular pathology of the thyroid.
OBJECTIVE
Endothelins (ETs) can act as autocrine and/or paracrine regulators of thyroid homeostasis and growth. The aim of this study was to evaluate immunoreactive ET (i-ET) levels in a group of patients with nodular pathology of the thyroid and to correlate them with the cytomorphological features after fine-needle aspiration (FNA) and with hormonal and immunological status and blood pressure levels.


METHODS
Plasma and cystic i-ET were assayed in a group of patients with varying thyroid function, who underwent FNA for solid and cystic nodular pathology.


METHODS
47 patients (32-81 years) with nodular pathology of the thyroid and 18 controls (28-70 years) with normal thyroid function and morphology were studied.


METHODS
Fasting venous blood samples were collected and the plasma for i-ET was frozen at -80 degrees C until assayed. Sera were frozen at -20 degrees C for FT3, FT4, TSH, TPO autoantibodies and thyroglobulin autoantibodies assay. Cystic fluid was obtained by FNA, centrifuged, and the supernatant was stored at -20 degrees C until i-ET assay. FNA cytology was examined by light microscopy.


RESULTS
In patients with cystic nodules, plasma i-ET levels were significantly (P = 0.002) higher (5.7 +/- 1.1 ng/l, +/- SEM) than in both patients with solid nodules (2.6 +/- 0.4 ng/l) and (P = 0.02) controls (3.0 +/- 0.3 ng/l). In patients with cystic nodules, cystic i-ET levels (12.6 +/- 1.9 ng/l) were significantly (P = 0.003) higher than plasma levels (5.7 +/- 1.1 ng/l) and did not correlate with the percentage of FNA cellularity. i-ET levels in cystic fluid (12.6 +/- 1.9 ng/l) were significantly (P = 0.0001) higher than plasma i-ET levels in both patients with solid nodules and controls. No difference in either plasma or cystic i-ET levels was found in patients with cystic nodules in relation to differences in thyroid function. No difference in plasma i-ET levels was found between patients with solid nodules and controls. In controls, no significant difference in plasma i-ET levels was found between males and females. A negative correlation (r = -0.55, P = 0.02) was found between cystic i-ET levels and systolic and diastolic blood pressure. No correlation between cystic or plasma i-ET levels and FT3, FT4 or TSH was found in any of the subjects studied.


CONCLUSIONS
It seems that endothelins do not possess a primary role in determining thyroid function and that the increased levels in cystic fluid found in our subjects could be secondary to cystic nodule development.
Foppiani
L
L
DISEM, Cattedra di Endocrinologia, Università di Genova, Italy.
Porcella
E
E
Cuttica
C M
CM
Fazzuoli
L
L
Valenti
S
S
Giordano
G
G
Giusti
M
M
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001707:Biopsy, Needle; D001794:Blood Pressure; D016232:Endothelins / Q000032:analysis* / Q000097:blood / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis; D016606:Thyroid Nodule / Q000378:metabolism* / Q000473:pathology
D016232:Endothelins