Surgery for hyperparathyroidism: does morphology or function matter most?
BACKGROUND
With minimally invasive parathyroidectomy (MIP) not all enlarged parathyroid glands are necessarily removed, and intraoperative measurement of parathyroid hormone levels (IO-PTH) does not necessarily predict multiple enlarged glands. The aim of this study was to compare morphology with function, using Ca(2+)-regulated PTH secretion.


METHODS
PTH secretion was determined by perifusion: (1) cells from 12 normal parathyroids were compared with 14 parathyroid adenomas; (2) functional characteristics (PTH secretion, sestamibi uptake, IO-PTH decrease) were correlated with morphologic characteristics; (3) PTH secretion as a predictor of IO-PTH decrease was determined in 7 patients with 2 enlarged parathyroids.


RESULTS
(1) There were significant differences between normal and pathological parathyroid cells consistent with reduced sensitivity to Ca(2+). Maximum secretion rates for normal and adenomatous cells were, respectively, 3.9 +/- 0.4 fg min(-1) cell(-1) and 2.0 +/- 0.4 fg min(-1) cell(-1) (P = .002) and minimum secretion rates, 0.7 +/- 0.1 fg min(-1) cell(-1) and 0.4 +/- 0.1 fg min(-1) cell(-1) (P = .008). However, the IC(50) value for Ca(2+) was elevated in adenomatous cells indicating an apparent loss of extracellular Ca(2+) sensitivity being 1.1 +/- 0.02 mmol/L for normal and 1.2 +/- 0.02 mmol/L for adenomatous cells (P = .02). (2) There was no overall correlation between PTH secretion and gland morphology. (3) In 5 of 7 cases, PTH secretion correctly predicted the decrease in IO-PTH.


CONCLUSIONS
Parathyroid adenomas generally exhibit abnormal PTH secretory function; however, enlarged parathyroid glands that do not contribute to the biochemical changes of hyperparathyroidism do exist, and, in these cases, cellular secretory function is a useful predictor of IO-PTH dynamics.
Mun
Hee-Chang
HC
School of Molecular and Microbial Biosciences, University of Sydney, Australia.
Conigrave
Arthur
A
Wilkinson
Margaret
M
Delbridge
Leigh
L
D000236:Adenoma / Q000378:metabolism* / Q000473:pathology* / Q000601:surgery; D016022:Case-Control Studies; D006801:Humans; D006961:Hyperparathyroidism / Q000209:etiology / Q000601:surgery; D019060:Minimally Invasive Surgical Procedures; D010280:Parathyroid Glands / Q000378:metabolism* / Q000473:pathology*; D010281:Parathyroid Hormone / Q000378:metabolism*; D010282:Parathyroid Neoplasms / Q000378:metabolism* / Q000473:pathology* / Q000601:surgery; D016105:Parathyroidectomy; D046509:Tissue Culture Techniques
D010281:Parathyroid Hormone