Acute suppression of parathyroid activity during hemofiltration.
Hemofiltration (HF) induces a significant reduction in parathormone (PTH). This effect is related not only to the convective removal of PTH molecules but also to the biological suppression of parathyroid glands by plasma-ionized calcium (iCa) increase. The acute inhibitory effect on parathyroid gland activity, ionized calcium mass balance, phosphate kinetics and intact PTH (PTHi) dialytic removal during post-dilution polyamide HF were studied in 31 chronic uremic patients. HF ensures good phosphate removal (from 2.54 +/- 1.19 to 1.27 +/- 0.35 mEq/l; p < 0.01), a positive iCa mass balance (8 +/- 4 mmol/session) with a iCa plasma increase and negligible convective PTHi removal (9 +/- 2 pg/ml). Study of the PTHi profile during HF characterized two different parathyroid responses: 26/31 patients showed a physiological parathyroid gland response to the iCa increase (from 1.17 +/- 0.09 to 1.42 +/- 0.07 mmol/l; p = 0.002) with a significant PTHi decrease (from 123 +/- 111 to 35 +/- 28 pg/ml; p = 0.01) and a maximal PTH inhibition of 88%. In 5 patients, with more severe hyperparathyroidism, in spite of a comparable increase in iCa (from 1.28 +/- 0.12 to 1.46 +/- 0.08 mmol/l; p = 0.02), this physiological calcium-PTHi feedback was lost, revealing an autonomization of the gland (maximal inhibition of 45%). In our experience, study of the PTHi profile during a single HF session may represent a clinical test for the functional exploration of parathyroid glands, suggesting future (medical or surgical) clinical strategy.
Panichi
V
V
Second Medical Clinic Institute, University of Pisa, Italy.
Bianchi
A M
AM
Andreini
B
B
Casarosa
L
L
Migliori
M
M
De Pietro
S
S
Ferdeghini
M
M
Palla
R
R
D000208:Acute Disease; D000328:Adult; D000368:Aged; D000469:Alkaline Phosphatase / Q000097:blood; D002117:Calcitriol / Q000097:blood; D002118:Calcium / Q000097:blood*; D006440:Hemofiltration / Q000009:adverse effects*; D006801:Humans; D007011:Hypoparathyroidism / Q000097:blood / Q000209:etiology*; D007700:Kinetics; D008875:Middle Aged; D015675:Osteocalcin / Q000097:blood; D010710:Phosphates / Q000097:blood*; D011347:Procollagen / Q000097:blood; D006435:Renal Dialysis / Q000009:adverse effects
D010710:Phosphates; D011347:Procollagen; D015675:Osteocalcin; D000469:Alkaline Phosphatase; D002117:Calcitriol; D002118:Calcium