Comparison of Profile of Primary Hyperparathyroidism With and Without Type 2 Diabetes Mellitus: Retrospective Analysis From the Indian Primary Hyperparathyroidism Registry.

OBJECTIVE: To describe the prevalence and compare the clinicobiochemical profile of patients with primary hyperparathyroidism (PHPT) with and without type 2 diabetes mellitus (T2DM). METHODS: We conducted a retrospective observational study wherein the details of patients with PHPT with T2DM (PHPT-T2DM) and without T2DM were retrieved from the Indian PHPT Registry (www.indianphptregistry.com) between 2005 and 2019. We compared the clinical, biochemical, and postoperative findings of patients with PHPT-T2DM with age-, sex-, and body mass index-matched patients with PHPT without T2DM (in 1:2 ratio). RESULTS: Of the 464 patients with PHPT, 54 (11.6%) had T2DM. We observed an increase in the prevalence of PHPT-T2DM cases over time; only 7 (7.1%) of the total patients with PHPT had T2DM between 2005 and 2009 that increased to 31 (12.8%) in the last half decade (2015-2019). Patients with PHPT-T2DM had a significantly lower prevalence of nephrolithiasis (18.5% vs 36.1%, respectively; P = .03) and a higher prevalence of pancreatitis (22.2% vs 5.6%, respectively; P = .007) than those without T2DM. Furthermore, intact parathyroid hormone (203 pg/mL [139.8-437.3 pg/mL] vs 285 pg/mL [166-692 pg/mL], respectively; P = .04) and serum creatinine (0.90 mg/dL [0.67-1.25 mg/dL] vs 1.10 mg/dL [0.73-1.68 mg/dL], respectively; P = .03) levels were significantly lower in patients with PHPT-T2DM than those without T2DM. Also, tumor weight tended to be lower in patients with PHPT-T2DM than in the non-T2DM counterparts (1.05 g [0.5-2.93 g] vs 2.16 g [0.81-7.0 g], respectively; P = .06). CONCLUSION: The prevalence of T2DM in Asian Indians with PHPT is 11.6%. Patients with PHPT-T2DM are characterized by a higher prevalence of pancreatitis, a lower prevalence of nephrolithiasis, and lower levels of intact parathyroid hormone/creatinine. Part of the clinical picture can possibly be explained by early detection of PHPT in patients with T2DM consequent to more frequent screening.

Aberrant Epigenetic Alteration of PAX1 Expression Contributes to Parathyroid Tumorigenesis.

CONTEXT: Primary hyperparathyroidism (PHPT) results from the hypersecretion of parathyroid hormone from parathyroid tumors. A transcription factor, namely Paired box1 (PAX1), is active in parathyroid gland development. OBJECTIVE: We aimed to study potential epigenetic-mediated mechanism of PAX1 gene in sporadic parathyroid adenomas. METHODS: In parathyroid adenomas tissues, we analyzed the DNA methylation via bisulfite-specific polymerase chain reaction (BSP) and histone modifications via chromatin immunoprecipitation in regulating the differential expression of PAX1. RESULTS: The results showed that mRNA and protein expression of PAX1 was significantly reduced in parathyroid adenomas. Bisulfite sequencing demonstrated hypermethylation in the promoter region of PAX1 (35%; 14/40) and lower levels of histone 3 lysine 9 acetylation (H3K9ac) were observed on the promoter region of PAX1 (6-fold; P < .004) in parathyroid adenomas. Furthermore, upon treatment with a pharmacologic inhibitor, namely 5'aza-2 deoxycytidine, in rat parathyroid continuous cells, we found re-expression of PAX1 gene. CONCLUSION: Our study not only reveals expression of PAX1 is epigenetically deregulated but also paves a way for clinical and therapeutic implications in patients with PHPT.

GCM2 Silencing in Parathyroid Adenoma Is Associated With Promoter Hypermethylation and Gain of Methylation on Histone 3.

CONTEXT: Glial cells missing 2 (GCM2), a zinc finger-transcription factor, is essentially required for the development of the parathyroid glands. OBJECTIVE: We sought to identify whether the epigenetic alterations in GCM2 transcription are involved in the pathogenesis of sporadic parathyroid adenoma. In addition, we examined the association between promoter methylation and histone modifications with disease indices. METHODS: Messenger RNA (mRNA) and protein expression of GCM2 were analyzed by reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR) and immunohistochemistry in 33 adenomatous and 10 control parathyroid tissues. DNA methylation and histone methylation/acetylation of the GCM2 promoter were measured by bisulfite sequencing and chromatin immunoprecipitation-qPCR. Additionally, we investigated the role of epigenetic modifications on GCM2 and DNA methyltransferase 1 (DNMT1) expression in parathyroid (PTH)-C1 cells by treating with 5-aza-2'-deoxycytidine (DAC) and BRD4770 and assessed for GCM2 mRNA and DNMT1 protein levels. RESULTS: mRNA and protein expression of GCM2 were lower in sporadic adenomatous than in control parathyroid tissues. This reduction correlated with hypermethylation (P < .001) and higher H3K9me3 levels in the GCM2 promoter (P < .04) in adenomas. In PTH-C1 cells, DAC treatment resulted in increased GCM2 transcription and decreased DNMT1 protein expression, while cells treated with the BRD4770 showed reduced H3K9me3 levels but a nonsignificant change in GCM2 transcription. CONCLUSION: These findings suggest the concurrent association of promoter hypermethylation and higher H3K9me3 with the repression of GCM2 expression in parathyroid adenomas. Treatment with DAC restored GCM2 expression in PTH-C1 cells. Our results showed a possible epigenetic landscape in the tumorigenesis of parathyroid adenoma and also that DAC may be a promising avenue of research for parathyroid adenoma therapeutics.

Differences in Primary Hyperparathyroidism Between Pre- and Postmenopausal Women in India.

OBJECTIVE: Primary hyperparathyroidism (PHPT) is a common endocrine disorder in women which becomes more prevalent after menopause. In this study, we compared the demographic, clinical, and biochemical variables between premenopausal (pre-M) and postmenopausal (post-M) women with PHPT. METHODS: A retrospective analysis (from 2005 to 2019) of enrolled women PHPT patients from an online Indian PHPT registry. RESULTS: Of the women with PHPT, 232 and 122 were pre-M and post-M, respectively. The number of post-M PHPT cases registered had a 3.3-fold increase in 2015-2019 from 2005-2009 compared with only a 2.5-fold increase in pre-M cases in the same duration. The majority were symptomatic (90%), although pre-M had a higher proportion of symptomatic than post-M (92% vs 85%; P = .04). Pre-M women showed more prevalence of osteitis fibrosa cystica than post-M women (28% vs 13%; P = .03), although hypertension and gallstone disease were seen more frequently in post-M PHPT women. Pre-M women had a significantly higher median PTH (403 vs 246 pg/mL; P = .02) and median alkaline phosphatase (202 vs 145 pg/mL; P = .02) than post-M women, and vitamin D deficiency was more common in pre-M women (58% vs 45%; P = .03). Gland localization, tumor weight, and disease cure rates did not differ according to menopausal status. CONCLUSION: PHPT was more prevalent in pre-M women, although the number of post-M cases had significantly increased in the last 10 years. Pre-M women had generally more severe clinical and biochemical variables than post-M PHPT women.

Parathyroid Carcinoma: An Experience from the Indian Primary Hyperparathyroidism Registry.

OBJECTIVE: To describe the details of widely invasive parathyroid carcinoma (WIPC) patients admitted in the Endocrinology department of our institute during the last 22 years and to compare their clinical, biochemical, and hormonal profile with minimally invasive parathyroid carcinoma (MIPC) and sporadic parathyroid adenoma patients. METHODS: This is a retrospective analysis of data from the Indian primary hyperparathyroidism registry. RESULTS: Of the 547 primary hyperparathyroidism patients in the registry, 5 (2 men and 3 women) had WIPC (0.9%) and 7 (1 man and 6 women) had MIPC (1.3%), with median ages of 45 (interquartile range, 41-51) years and 47 (interquartile range, 28-48) years, respectively. Among the patients with WIPC, renal manifestations were present in 5 patients, skeletal manifestations in 4 patients, and palpable neck masses in 4 patients. Three patients had distant metastases and 2 had cervical lymph node involvement. All 5 patients had surgical resection of their cancers, with persistent disease in 4 patients, but all patients died within 2 years after surgery. One patient with MIPC had a palpable parathyroid nodule; none had lymph nodal or distant metastases. None of the patients with MIPC died during the median follow-up of 18 (interquartile range, 12-18) months. Patients with WIPC had significantly higher serum calcium level compared with sporadic parathyroid adenoma patients with skeletal and renal manifestations. CONCLUSION: Accurate histopathologic classification of parathyroid carcinoma is important as WIPC is associated with a more aggressive clinical course and a higher risk of mortality than MIPC.

Progressive rise in the prevalence of asymptomatic primary hyperparathyroidism in India: Data from PHPT registry.

INTRODUCTION: Primary hyperparathyroidism (PHPT), a third common endocrine disorder, varies from asymptomatic disease, mostly seen in the West where routine biochemical screening is practiced, to the classical symptomatic disease mostly seen in the Eastern countries. We aimed to compare the demographic, clinical, biochemical measurements in patients with asymptomatic and symptomatic PHPT from the Indian PHPT registry. MATERIAL AND METHODS: Data of PHPT patients from the last 25 years (1995-2019) were analyzed for demographic, clinical presentation and biochemical measurements, and compared these characteristics between asymptomatic and symptomatic PHPT patients. RESULTS: Of the 554 patients, 54 (10%) patients had asymptomatic PHPT. There was a sharp rise in the proportion of asymptomatic PHPT patients of 3% in the first decade to 13% in the second decade of the century (p = 0.003). Patients with asymptomatic PHPT were significantly older (50 vs. 42 years; p < 0.0001) and had higher mean body mass index (27.8 vs. 23.5 kg/m2; p < 0.0001) compared to the symptomatic PHPT group. In addition, asymptomatic PHPT patients had significantly lower median plasma iPTH (180 vs. 370 pg/mL; p < 0.0001), serum alkaline phosphatase (119 vs. 172 IU/L; p < 0.0001), and parathyroid adenoma weight (1.0 vs. 2.62 g; p = 0.006) compared to the symptomatic PHPT group. CONCLUSION: Although symptomatic PHPT is still most prevalent (> 90%) in India with higher indices of the disease and tumor weights, there is a progressive rise in the prevalence of asymptomatic PHPT patients in the last decade. Improvements in calcium and vitamin D nutrition might account for this change as in the Western series.

A detailed appraisal of renal manifestations in primary hyperparathyroidism from Indian PHPT registry: Before and after curative parathyroidectomy.

BACKGROUND: Primary hyperparathyroidism (PHPT) is a systemic disorder characterized by hypercalcaemia and inappropriately elevated parathyroid hormone (PTH). Renal manifestations are one of the main presenting features both in symptomatic and asymptomatic PHPT patients. OBJECTIVES: We aimed to compare demographic, clinical and biochemical parameters of PHPT patients with and without renal manifestations and also analysed the influence of curative parathyroidectomy on renal functions. METHODS: We retrospectively analysed the data of PHPT patients from the last 25 years (1995- March 2019) and compared the demographic and clinical presentation and biochemical measurements between patients with and without renal manifestations and evaluated the changes in renal functions after 1 year of curative parathyroidectomy. RESULTS: Of the total 544 PHPT patients, 299 (55%) including 91 out of 141 (65%) males had renal manifestations. Among renal manifestations, nephrolithiasis and nephrocalcinosis were found in 41.7% and 27.6% PHPT patients, respectively. PHPT patients with renal manifestations had significantly higher creatinine (109.7 vs 79.6 µmol/L; P < .0001) and lower eGFR level (78.8 vs 93.9 mL/min/1.73 m2 ; P < .0001) compared to patients without renal manifestations. Parathyroidectomy resolved the clinical symptoms with biochemical cure in the patients from both the groups. Patients with renal manifestations showed improvement in creatinine and eGFR levels after 1 year of curative parathyroidectomy; however, patients without renal manifestations showed no change in creatinine and eGFR levels. CONCLUSION: Young age and male gender are predictors of renal manifestations in PHPT. Curative parathyroidectomy improves renal functions in PHPT patients with renal manifestations compared to PHPT patients without renal manifestation.

Reduced Calcium Sensing Receptor (CaSR) Expression Is Epigenetically Deregulated in Parathyroid Adenomas.

AIM: Reduced calcium sensing receptor (CaSR) expression has been implicated in parathyroid tumorigenesis, but the underlying mechanism remains elusive. Accordingly, we aimed to explore the epigenetic changes (DNA methylation and histone modifications) involved in CaSR regulation in sporadic parathyroid adenomas and correlate epigenetic state with disease indices. EXPERIMENTAL DESIGN: Forty sporadic parathyroid adenomas and 10 control parathyroid tissues were studied. Real-time quantitative PCR (qPCR) for mRNA and immunohistochemistry for protein expression of CaSR were performed. The methylation status of the CaSR promoter 2 was determined by bisulphite sequencing analysis of sodium bisulphite-converted DNA. To determine the role of histone modifications in the CaSR regulation, chromatin immunoprecipitation-qPCR assay was performed. RESULTS: Real-time qPCR revealed reduced CaSR mRNA expression with a fold reduction of 0.12 (P < 0.0001) in parathyroid adenomas. Immunohistochemistry revealed reduced protein expression of CaSR in 90% (36/40) of adenomas. The promoter 2 region of CaSR displayed significant hypermethylation in 45% (18/40) of the adenomas compared with the controls (6.7%; 1 of 10) (P < 0.002). Bisulphite sequencing analysis revealed maximum methylated CpG at glial cell missing 2 binding site on the CaSR promoter 2 compared to other CpG sites. The methylation status of CaSR correlated directly with plasma intact parathyroid hormone levels in patients with parathyroid adenoma. With chromatin immunoprecipitation-qPCR analysis, H3K9me3 levels showed increased enrichment by 10-fold in adenomas and correlated with CaSR-mRNA expression (r = 0.61; P < 0.003). Treatment with 5-aza-2'deoxycytidine restored the expression of CaSR in a parathyroid cell line. CONCLUSION: Our data suggest that hypermethylation and increased H3K9me3 of the CaSR promoter 2 are involved in silencing CaSR expression in sporadic parathyroid adenoma.

Minimally invasive parathyroid carcinoma-A missing entity between parathyroid adenoma and carcinoma: Scintigraphic and histological features.

PURPOSE: Minimally invasive parathyroid carcinoma (MIPC) is clinically and biochemically comparable with parathyroid adenoma (PA) though histopathologically differ from PA. MIPC is an intermediate of PA and parathyroid carcinoma (PC). In literature, there is no definite criterion to diagnose MIPC. Our aim was to evaluate and characterize the imaging and biochemical parameters with histological characteristics of MIPC. METHODOLOGY: Ten patients with MIPC were recruited from (single centre) Indian PHPT registry (www.indianphptregistry.com) from January 2014 to July 2018. Clinical, biochemical, imaging and histological features of MIPC patients were reviewed. RESULTS: The mean age of MIPC patients (n = 10; 3 males) was 39.9 ± 11.3 years (range: 17-50). All patients had an elevated preoperative parathyroid hormone (iPTH) level ranging from 427 to 2138 pg/mL (median: 1328). MIBI scan showed intensely avid and enlarged parathyroid tumours in all patients; LIPT in 6, RIPT in 3 and ectopic mediastinal in 1 with mean size of the tumours was 2.8 ± 1.1 cm. The mean of maximum standardized uptake value (SUVmax) of MIPC in F-18 fluorocholine PET/CT was 6.7 ± 1.1 (range 6.0-8.3). The mean tumour weight was 12 ± 9.5 g (range: 1.09-28). All MIPC patients had identified capsular invasion in 80% and vascular invasion in 50% only but there was no local invasion, lymph nodal or distant metastasis. The mean Ki-67 labelling index was 3.2 ± 2.7 (range 1.1-10). CONCLUSION: The study concluded that MIPC patients are less aggressive (on the basis of imaging and histopathological findings) and should be differentiated from parathyroid adenoma and carcinoma.

Deficiency in the secreted protein Semaphorin3d causes abnormal parathyroid development in mice.

Primary hyperparathyroidism (PHPT) is a common endocrinopathy characterized by hypercalcemia and elevated levels of parathyroid hormone. The primary cause of PHPT is a benign overgrowth of parathyroid tissue causing excessive secretion of parathyroid hormone. However, the molecular etiology of PHPT is incompletely defined. Here, we demonstrate that semaphorin3d (Sema3d), a secreted glycoprotein, is expressed in the developing parathyroid gland in mice. We also observed that genetic deletion of Sema3d leads to parathyroid hyperplasia, causing PHPT. In vivo and in vitro experiments using histology, immunohistochemistry, biochemical, RT-qPCR, and immunoblotting assays revealed that Sema3d inhibits parathyroid cell proliferation by decreasing the epidermal growth factor receptor (EGFR)/Erb-B2 receptor tyrosine kinase (ERBB) signaling pathway. We further demonstrate that EGFR signaling is elevated in Sema3d-/- parathyroid glands and that pharmacological inhibition of EGFR signaling can partially rescue the parathyroid hyperplasia phenotype. We propose that because Sema3d is a secreted protein, it may be possible to use recombinant Sema3d or derived peptides to inhibit parathyroid cell proliferation causing hyperplasia and hyperparathyroidism. Collectively, these findings identify Sema3d as a negative regulator of parathyroid growth.

PRIMARY HYPERPARATHYROIDISM IN THE YOUNG: COMPARISON WITH ADULT PRIMARY HYPERPARATHYROIDISM.

OBJECTIVE: Primary hyperparathyroidism (PHPT) is relatively common among adults but rarely encountered in children and adolescents. According to the western literature, young PHPT is different from adult PHPT and is associated with more severe hypercalcemia. PHPT in the adult Indian population is different from its western counterpart. Here we present the clinical, biochemical, and surgical characteristics of young patients with PHPT treated at our tertiary care center. METHODS: PHPT patients were divided into adult (≥25 years) and young (<25 years) groups. The clinical, biochemical, hormonal, and histopathologic characteristics and treatment outcomes in the groups were compared. RESULTS: Out of 358 patients, 47 patients were young and 311 patients were adults. The mean ages of the groups were 19 ± 4 and 45 ± 12 years, respectively. The corresponding female-to-male ratios were 1.24:1 and 3.38:1 ( P<.05). The nature and frequency of presenting symptoms were comparable between the 2 groups. The most common symptom in young patients with PHPT was bone pain and was not significantly different from adults (57% vs. 61%, respectively). The most common symptom in adult PHPT was fatigue, which was also not significantly different from young patients (63% vs. 53%, respectively), The serum calcium, phosphate, 25-hydroxyvitamin D levels; alkaline phosphatase Z-score; and parathyroid hormone levels were comparable between the 2 groups. Parathyroid adenoma was the most common histopathologic finding, while hyperplasia was rare in both groups. CONCLUSION: We observed that young PHPT is not markedly different from its adult counterpart in an Indian population. ABBREVIATIONS: ALP = alkaline phosphatase; Ca = calcium; Cr = creatinine; iPTH = intact parathyroid hormone; 25(OH)D = 25-hydroxyvitamin D; P = phosphate; PHPT = primary hyperparathyroidism; PTH = parathyroid hormone; RR = reference range; 99mTc sestamibi = technetium sestamibi; USG = ultrasonography.

Primary hyperparathyroidism: insights from the Indian PHPT registry.

The presentation of primary hyperparathyroidism (PHPT) is variable throughout the world. The present study explored retrospective data submitted to the Indian PHPT registry ( http://www.indianphptregistry.com ) between July 2005 and June 2015 from 5 centres covering four different geographical regions. The clinical, biochemical, radiological and histopathological characteristics of PHPT patients across India were analysed for similarity and variability across the centres. A total of 464 subjects (137 men and 327 women) with histopathologically proven PHPT were analysed. The mean age was 41 ± 14 years with a female:male ratio of 2.4:1. The majority (95%) of patients were symptomatic. Common clinical manifestations among all the centres were weakness and fatigability (58.7%), bone pain (56%), renal stone disease (31%), pancreatitis (12.3%) and gallstone disease (11%). Mean serum calcium, parathyroid hormone and inorganic phosphorus levels were 11.9 ± 1.6 mg/dL, 752.4 ± 735.2 pg/mL and 2.8 ± 0.9 mg/dL, respectively. Sestamibi scanning had better sensitivity than ultrasonography in the localisation of parathyroid adenoma; however, when these two modalities were combined, 93% of the cases were correctly localised. Mean parathyroid adenoma weight was 5.6 ± 6.5 g (0.1-54 g). It was concluded that the majority of PHPT patients within India are still mainly symptomatic with >50% of patients presenting with bone disease and one-third with renal impairment. Compared to Western countries, Indian patients with PHPT are younger, biochemical abnormalities are more severe, and adenoma weight is higher. As our observation is largely derived from a tertiary care hospital (no routine screening of serum calcium level), the results do not reflect racial differences in susceptibility to PHPT.

Frequency & predictors of pancreatitis in symptomatic primary hyperparathyroidism.

BACKGROUND & OBJECTIVES: The frequency and predictors of pancreatitis in primary hyperparathyroidism (PHPT) are not well understood. The objective of the present study was to evaluate the frequency of pancreatitis in patients with PHPT and its association with clinical and biochemical parameters of the disease. METHODS: In this retrospective study all consecutive patients with PHPT registered in the PHPT registry (www.indianphptregistry.com) from the year 2004 to 2013 were included. The clinical, biochemical and radiological parameters related to pancreatitis were evaluated in histologically proven PHPT patients. RESULTS: A total of 218 patients (63 men; mean age: 40.6±14.4 yr) underwent surgery for PHPT during the study. Pancreatitis occurred in 35 [16%, 18 acute and 17 chronic pancreatitis (CP)] patients and male:female ratio was 1:0.94. Skeletal manifestations were seen less frequently in PHPT with pancreatitis as compared to that of PHPT without pancreatitis. PHPT with pancreatitis had significantly higher serum calcium (12.4±2.0 vs. 11.7±1.5 mg/dl, P <0.05) in comparison to PHPT without pancreatitis. PHPT with acute pancreatitis (AP) had higher serum calcium (P <0.05) and parathyroid hormone (PTH) (P <0.05) levels than PHPT with CP. Curative parathyroidectomy improved the symptoms associated with pancreatitis as there was no recurrence in AP group, whereas recurrence was observed only in about 10 per cent patients of the CP group. INTERPRETATION & CONCLUSIONS: Pancreatitis was observed in 16 per cent of PHPT patients with male predominance in the study population. No recurrence of AP was observed after curative surgery. It may be proposed that serum amylase with calcium and PTH should be measured in all patients of PHPT with pain abdomen to rule out pancreatitis.

Promoter hypermethylation inactivates CDKN2A, CDKN2B and RASSF1A genes in sporadic parathyroid adenomas.

Cyclin D1, a G1-S phase regulator, is upregulated in parathyroid adenomas. Since cyclin-dependent kinase (CDK) inhibitors, CDKN2A and CDKN2B, and RASSF1A (Ras-association domain family 1, isoform A) are involved in G1-S phase arrest and act as potential tumor suppressor genes, we aimed to study potential methylation-mediated inactivation of these genes in parathyroid adenomas. Gene expressions of cyclin D1 (CCND1) and regulatory molecules (CDKN2A, CDKN2B and RASSF1A) was analysed in parathyroid adenoma tissues (n = 30). DNA promoter methylation of cyclin D1 regulators were assessed and correlated with clinicopathological features of the patients. Gene expression analysis showed a relative fold reductions of 0.35 for CDKN2A (p = 0.01), 0.45 for CDKN2B (P = 0.02), and 0.39 for RASSF1A (p < 0.01) in adenomatous compared to normal parathyroid tissue. There was an inverse relationship between the expressions of CDKN2A and CDKN2B with CCND1. In addition, the promoter regions of CDKN2A, CDKN2B, and of RASSF1A were significantly hyper-methylated in 50% (n = 15), 47% (n = 14), and 90% (n = 27) of adenomas respectively. In contrast, no such aberrant methylation of these genes was observed in normal parathyroid tissue. So, promoter hypermethylation is associated with down-regulation of CCND1 regulatory genes in sporadic parathyroid adenomas. This dysregulated cell cycle mechanism may contribute to parathyroid tumorigenesis.

ANABOLIC BONE WINDOW WITH WEEKLY TERIPARATIDE THERAPY IN POSTMENOPAUSAL OSTEOPOROSIS: A PILOT STUDY.

OBJECTIVE: Osteoporosis is a major public health problem that reduces bone strength and increases fracture risk. Teriparatide is an established and the only currently available anabolic therapy for the treatment of postmenopausal osteoporosis (PMO) with a recommended daily dose of 20 µg given subcutaneously. However, there are limited data regarding the long-term effect of once-weekly teriparatide therapy on bone mineral density (BMD), bone turnover markers (BTMs), and anabolic bone window. METHODS: In this prospective observational study, 26 patients with PMO were treated with weekly teriparatide therapy (60 µg) for 2 years. BMD was measured at baseline, 12 months, and 24 months. The bone formation marker type 1 collagen C-terminal propeptide (P1NP) and the bone resorption marker C-terminal telopeptide of type 1 collagen (CTx) were measured at baseline; 6 weeks; and 6, 12, 18, and 24 months. RESULTS: BMDs at the lumbar spine increased by 3.1% and 10.8% after 1 and 2 years of weekly teriparatide therapy, respectively. The T-score increased significantly at the lumbar spine compared to baseline after 2 years of therapy (P = .015). Serum P1NP levels increased significantly at 6 months (P = .024), peaked at 1 year, and remained above the baseline even after 2 years. Serum CTx levels decreased significantly at 6 months (P = .025) and remained below baseline after 2 years of teriparatide therapy. CONCLUSION: Weekly teriparatide therapy (60 µg) appears to be as effective as daily teriparatide for the treatment of PMO by extending the anabolic bone window. ABBREVIATIONS: AE = adverse event; BMD = bone mineral density; BTM = bone turnover marker; CTx = C-terminal telopeptide of type 1 collagen; DXA = dual-energy X-ray absorptiometry; iPTH = intact parathyroid hormone; P1NP = type 1 collagen C-terminal propeptide; PMO = postmenopausal osteoporosis.

Changes in plasma intact parathyroid hormone levels following 24-hour incubation at room temperature as determined by Roche electrochemiluminescence PTH immunoassay.

BACKGROUND: Estimation of circulatory PTH is necessary for correct diagnosis of diseases related to the parathyroid gland, bone, and kidney. METHODS: Roche Electrochemiluminescence PTH immunoassay was used to measure changes in plasma iPTH concentration in 100 random samples following a 24 hours incubation at room temperature. RESULTS: Low to normal iPTH concentration individuals showed higher decrease in iPTH concentration as compared to individuals with elevated PTH and the rate of PTH degradation was significantly higher (p < 0.05) in the low to normal PTH group. CONCLUSIONS: Blood samples from suspected hypo- or normo-parathyroid subjects should be analyzed as soon as possible as a little degradation of PTH at room temperature could influence their clinical interpretation.

Changes in parathyroid proteome in patients with primary hyperparathyroidism due to sporadic parathyroid adenomas.

PURPOSE: The pathogenesis of parathyroid tumours is only partially understood. A direct approach using proteomics could be a promising tool to increase our understanding of parathyroid tumorigenesis. The aim of the study was to investigate differentially expressed proteins to explore the underlying molecular basis of the disease and identify potential target proteins responsible for the genesis of adenoma. METHODS: Proteins were extracted from adenomatous and normal parathyroid tissues. Differentially expressed proteins were separated by two-dimensional gel electrophoresis (2-D) and identified by matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry. Statistical analysis was performed using spss 10.01 software. RESULTS: Comparative analysis of the 2-D profiles of proteins isolated from adenomatous and normal parathyroid tissues showed 15 differentially expressed proteins, of which 11 were overexpressed. The characterized proteins were associated with diverse cellular functions including regulation of cell organization, programmed cell death, transcription and signal transduction. CONCLUSION: The differentially expressed proteins in parathyroid adenomas may potentially serve as new targets to investigate the mechanisms of parathyroid adenoma transformation.

Methylation status of the CpG islands in vitamin D and calcium-sensing receptor gene promoters does not explain the reduced gene expressions in parathyroid adenomas.

AIM: The exact mechanism causing decreased expression of the vitamin D receptor (VDR) and calcium-sensing receptor (CASR) genes in parathyroid adenoma is not known, but methylation of promoter regions is often detected during epigenetic downregulation of gene expression. We investigated whether epigenetic silencing is involved in the decreased expression of VDR and CASR. EXPERIMENTAL DESIGN: Real-time PCR and immunohistochemistry confirmed the downregulation of the VDR and CASR genes at transcriptional and translational levels. Bisulfite-converted DNA samples from parathyroid adenomas with control samples were analyzed for methylation in the promoter region of VDR and CASR genes. RESULTS: There was no significant methylation in the promoter regions of VDR and CASR genes in parathyroid adenomatous tissues. CONCLUSIONS: Methylation-mediated silencing of VDR and CASR promoter does not appear to be associated with reduced expression, indicating the involvement of other factors in specific suppression of VDR and CASR in parathyroid adenomas.

Simultaneous expression analysis of vitamin D receptor, calcium-sensing receptor, cyclin D1, and PTH in symptomatic primary hyperparathyroidism in Asian Indians.

BACKGROUND: To explore underlying molecular mechanisms in the pathogenesis of symptomatic sporadic primary hyperparathyroidism (PHPT). MATERIALS AND METHODS: Forty-one parathyroid adenomas from patients with symptomatic PHPT and ten normal parathyroid glands either from patients with PHPT (n=3) or from euthyroid patients without PHPT during thyroid surgery (n=7) were analyzed for vitamin D receptor (VDR), calcium-sensing receptor (CASR), cyclin D1 (CD1), and parathyroid hormone (PTH) expressions. The protein expressions were assessed semiquantitatively by immunohistochemistry, based on percentage of positive cells and staining intensity, and confirmed by quantitative real-time PCR. RESULTS: Immunohistochemistry revealed significant reductions in VDR (both nuclear and cytoplasmic) and CASR expressions and significant increases in CD1 and PTH expressions in adenomatous compared with normal parathyroid tissue. Consistent with immunohistochemistry findings, both VDR and CASR mRNAs were reduced by 0.36- and 0.45-fold change (P<0.001) and CD1 and PTH mRNAs were increased by 9.4- and 17.4-fold change respectively (P<0.001) in adenomatous parathyroid tissue. PTH mRNA correlated with plasma PTH (r=0.864; P<0.001), but not with adenoma weight, while CD1 mRNA correlated with adenoma weight (r=0.715; P<0.001). There were no correlations between VDR and CASR mRNA levels and serum Ca, plasma intact PTH, or 25-hydroxyvitamin D levels. In addition, there was no relationship between the decreases in VDR and CASR mRNA expressions and the increases in PTH and CD1 mRNA expressions. CONCLUSIONS: The expression of both VDR and CASR are reduced in symptomatic PHPT in Asian Indians. In addition, CD1 expression was greatly increased and correlated with adenoma weight, implying a potential role for CD1 in adenoma growth and differential clinical expression of PHPT.