Mice deleted for cell division cycle 73 gene develop parathyroid and uterine tumours: model for the hyperparathyroidism-jaw tumour syndrome.

The hyperparathyroidism-jaw tumour (HPT-JT) syndrome is an autosomal dominant disorder characterized by occurrence of parathyroid tumours, often atypical adenomas and carcinomas, ossifying jaw fibromas, renal tumours and uterine benign and malignant neoplasms. HPT-JT is caused by mutations of the cell division cycle 73 (CDC73) gene, located on chromosome 1q31.2 and encodes a 531 amino acid protein, parafibromin. To facilitate in vivo studies of Cdc73 in tumourigenesis we generated conventional (Cdc73+/-) and conditional parathyroid-specific (Cdc73+/L/PTH-Cre and Cdc73L/L/PTH-Cre) mouse models. Mice were aged to 18-21 months and studied for survival, tumour development and proliferation, and serum biochemistry, and compared to age-matched wild-type (Cdc73+/+ and Cdc73+/+/PTH-Cre) littermates. Survival of Cdc73+/- mice, when compared to Cdc73+/+ mice was reduced (Cdc73+/-=80%; Cdc73+/+=90% at 18 months of age, P<0.05). Cdc73+/-, Cdc73+/L/PTH-Cre and Cdc73L/L/PTH-Cre mice developed parathyroid tumours, which had nuclear pleomorphism, fibrous septation and increased galectin-3 expression, consistent with atypical parathyroid adenomas, from 9 months of age. Parathyroid tumours in Cdc73+/-, Cdc73+/L/PTH-Cre and Cdc73L/L/PTH-Cre mice had significantly increased proliferation, with rates >fourfold higher than that in parathyroid glands of wild-type littermates (P<0.0001). Cdc73+/-, Cdc73+/L/PTH-Cre and Cdc73L/L/PTH-Cre mice had higher mean serum calcium concentrations than wild-type littermates, and Cdc73+/- mice also had increased mean serum parathyroid hormone (PTH) concentrations. Parathyroid tumour development, and elevations in serum calcium and PTH, were similar in males and females. Cdc73+/- mice did not develop bone or renal tumours but female Cdc73+/- mice, at 18 months of age, had uterine neoplasms comprising squamous metaplasia, adenofibroma and adenomyoma. Uterine neoplasms, myometria and jaw bones of Cdc73+/- mice had increased proliferation rates that were 2-fold higher than in Cdc73+/+ mice (P<0.05). Thus, our studies, which have established mouse models for parathyroid tumours and uterine neoplasms that develop in the HPT-JT syndrome, provide in vivo models for future studies of these tumours.

Bilateral adrenalectomy: a review of 10 years' experience.

INTRODUCTION The 2012 British Association of Endocrine and Thyroid Surgeons audit report showed that only 86 of 1359 patients who underwent adrenalectomy had a bilateral operation; thus the experience with this procedure remains limited. METHODS Retrospective review of patients undergoing bilateral adrenalectomy in a tertiary referral centre. RESULTS Between November 2005 and January 2016, bilateral adrenalectomy was performed in 23 patients (6 male, 17 female, age 43 ± 4 years) diagnosed with Cushing's disease (n = 13), hereditary phaeochromocytomas (n = 6), adrenocortical cancer (n = 2), colorectal metastatic disease (n = 1) and adrenocortical adenomas (n = 1). A laparoscopic transperitoneal approach was used in 17 patients, with one conversion to open. Three patients had open adrenalectomies for adrenocortical cancer and for simultaneous phaeochromocytomas and pancreatic neuroendocrine tumours in a patient with Von Hippel-Lindau syndrome. Three patients with Cushing's had a bilateral retroperitoneoscopic operation. The mean operating time was 195 ± 16 minutes for laparoscopic operations (n = 16), 243 ± 44 minutes for open adrenalectomies (n = 4) and 151 ± 12 minutes for retroperitoneal operations. It was significantly shorter for Cushing's disease than for phaeochromocytomas (162 ± 8 vs. 257 ± 39 minutes, P < 0.01). Median length of hospital stay was 5 days. Postoperative complications (Clavien-Dindo classification) included one chest infection (level 2), one postoperative haemorrhage and two chest drains for pneumothorax (level 3), two postoperative cardiac arrests (level 4) and one late cancer death from complications related to uncontrolled hypercortisolism (level 5). DISCUSSION Synchronous bilateral adrenalectomy remains an infrequent operation. The laparoscopic approach is feasible in the majority of patients. It is likely that the retroperitoneoscopic adrenalectomy will become the standard approach for bilateral operations.

The long lifespan and low turnover of human islet beta cells estimated by mathematical modelling of lipofuscin accumulation.

AIMS/HYPOTHESIS: Defects in pancreatic beta cell turnover are implicated in the pathogenesis of type 2 diabetes by genetic markers for diabetes. Decreased beta cell neogenesis could contribute to diabetes. The longevity and turnover of human beta cells is unknown; in rodents <1 year old, a half-life of 30 days is estimated. Intracellular lipofuscin body (LB) accumulation is a hallmark of ageing in neurons. To estimate the lifespan of human beta cells, we measured beta cell LB accumulation in individuals aged 1-81 years. METHODS: LB content was determined by electron microscopical morphometry in sections of beta cells from human (non-diabetic, n = 45; type 2 diabetic, n = 10) and non-human primates (n = 10; 5-30 years) and from 15 mice aged 10-99 weeks. Total cellular LB content was estimated by three-dimensional (3D) mathematical modelling. RESULTS: LB area proportion was significantly correlated with age in human and non-human primates. The proportion of human LB-positive beta cells was significantly related to age, with no apparent differences in type 2 diabetes or obesity. LB content was low in human insulinomas (n = 5) and alpha cells and in mouse beta cells (LB content in mouse <10% human). Using 3D electron microscopy and 3D mathematical modelling, the LB-positive human beta cells (representing aged cells) increased from >or=90% (<10 years) to >or=97% (>20 years) and remained constant thereafter. CONCLUSIONS/INTERPRETATION: Human beta cells, unlike those of young rodents, are long-lived. LB proportions in type 2 diabetes and obesity suggest that little adaptive change occurs in the adult human beta cell population, which is largely established by age 20 years.