Menopausal Age of Females with Hypercalcaemia

Prolactin receptor in primary hyperparathyroidism--expression, functionality and clinical correlations

Background

Primary hyperparathyroidism (PHPT) is an endocrine disorder most commonly affecting women, suggesting a role for female hormones and/or their receptors in parathyroid adenomas. We here investigated the prolactin receptor (PRLr) which is associated with tumours of the breast and other organs.

Methodology/Principal Findings

PRLr expression was investigated in a panel of 37 patients with sporadic parathyroid tumours and its functionality in cultured parathyroid tumour cells. In comparison with other tissues and breast cancer cells, high levels of prolactin receptor gene (PRLR) transcripts were demonstrated in parathyroid tissues. PRLr products of 60/70 kDa were highly expressed in all parathyroid tumours. In addition varying levels of the 80 kDa PRLr isoform, with known proliferative activity, were demonstrated. In parathyroid tumours, PRLr immunoreactivity was observed in the cytoplasm (in all cases, n = 36), cytoplasmic granulae (n = 16), the plasma membrane (n = 12) or enlarged lysosomes (n = 4). In normal parathyroid rim (n = 28), PRLr was uniformly expressed in the cytoplasm and granulae. In in vitro studies of short-term cultured human parathyroid tumour cells, prolactin stimulation was associated with significant transcriptional changes in JAK/STAT, RIG-I like receptor and type II interferon signalling pathways as documented by gene expression profiling. Moreover, PRLR gene expression in parathyroid tumours was inversely correlated with the patients’ plasma calcium levels.

Conclusions

We demonstrate that the prolactin receptor is highly abundant in human parathyroid tissues and that PRLr isoforms expression and PRLr subcellular localisation are altered in parathyroid tumours. Responsiveness of PRLr to physiological levels of prolactin was observed in the form of increased PTH secretion and altered gene transcription with significant increase of RIG-I like receptor, JAK-STAT and Type II interferon signalling pathways. These data suggest a role of the prolactin receptor in parathyroid adenomas.

Parathyroidectomy improves concentration and retentiveness in patients with primary hyperparathyroidism

BACKGROUND

Many patients with primary hyperparathyroidism (PHPT) show symptoms of hypercalcemia syndrome, including psychologic and psychiatric disorders. The aim of this study was to find out whether parathyroidectomy improves cognitive performance with regard to concentration and retentiveness in patients with PHPT.

METHODS

. Twenty patients with PHPT underwent psychologic testing preoperatively as well as 6 and 12 weeks postoperatively. Concentration under stress (timing) was proved by the d2-Test of Attention. To evaluate retentiveness, parts of the Wilde Intelligence Test were used. Patients were tested under identical circumstances with regard to time, location, and tester to minimize exterior influences.

RESULTS

The patients' concentration enhanced significantly postoperatively (P <.001). The same applied to the total number of items processed (P <.01). Improvement of patients' ability to memorize numbers reached statistical significance when comparing the preoperative with the postoperative result (P =.0396); furthermore, there was a tendency to perform the tests more carefully and accurately (P =.069).

CONCLUSIONS

Parathyroidectomy not only betters physical symptoms of PHPT but can also positively influence the patients' cognitive performance. These findings reflect the clinical observation of the patients' improved mental capacity after parathyroidectomy.

Childbearing and the risk of parathyroid adenoma--a dominant cause for primary hyperparathyroidism

OBJECTIVES

To explore possible associations between the reproductive history amongst women and the risk of parathyroid adenoma (PA).

DESIGN

Two nationwide Swedish registries. The Fertility Register included data on more than 3.4 million livebirths between 1943 and 1992 amongst Swedish females born 1925-72. The Cancer Register encompasses more than 1800 women with a diagnosis of PA 1960 until 1992.

SETTING

All women resident in Sweden 1960-92.

SUBJECTS

Cases were all 1800 women born 1925-72 reported to the Swedish Cancer Registry with a histopathological diagnosis of PA. Five controls were selected at random for each case by matching for the month and year of birth. Conditional logistic regression was used to estimate relative risks of PA.

MAIN OUTCOMES

Parathyroid adenoma.

RESULTS

High parity (four or more live births) was associated with an increased risk of PA. Amongst women with a diagnosis of PA before menopause (i.e. the age of 50 years) there was an increased risk of PA with younger age at first childbirth. Nulliparous women were at increased risk for PA before menopause, and at decreased risk after menopause.

CONCLUSIONS

There is an association between childbearing and the risk of PA, which has not previously been demonstrated, but the underlying biological mechanisms remain to be determined.

Premature death in patients operated on for primary hyperparathyroidism

To investigate long-term survival after operation for primary hyperparathyroidism, a follow-up study was performed on 896 consecutive patients in whom this diagnosis had been clinically and microscopically verified. These patients were operated on in the years 1953-1982. Their mean age at operation was 57.3 years [standard deviation (SD) 13.1], overall cure rate was 97.0%, and postoperative mortality was 0.89%. Follow-up was 99.8% complete by the end of 1986. Mean follow-up time was 12.9 years (SD: 6.1). Two-hundred ninety-four patients were deceased, which was 118 more than in a control group (p less than 0.001). The latter was based on Swedish population statistics, matched for age, sex, and calendar year. Each year, the control group was the same size as the hyperparathyroid population. The risk of premature death remained increased (p less than 0.001) even after exclusion of poor-risk patients having their hyperparathyroidism diagnosed when being treated or followed because of other serious diseases. The main causes of premature death for the hyperparathyroid patients were cardiovascular and malignant diseases. Both occurred more often than in the control group (p less than 0.001). The results demonstrate that primary hyperparathyroidism causes damage that is not reversed by surgery.