Innate differences in the molecular signature of normal inferior & superior human parathyroid glands: potential implications for parathyroid adenoma.

Primary hyperparathyroidism is a common endocrine disorder. Interestingly, the majority (75%) of parathyroid tumors are localized to the inferior parathyroid glands. To date, the reason for this natural bias has not been investigated. We assessed the global gene expression profile of superior and inferior glands obtained from forensic autopsies. The genes with significant differential expression between superior and inferior parathyroids were further assessed by RT-PCR in 19 pairs. As an iterative approach, additional genes with an established role in parathyroid disorders, i.e., CASR, MAFB, PAX9, TBCE, TBX1, VDR, MEN1, CCND1, and CDC73 were also evaluated by RT-PCR in all 19 pairs of superior and inferior parathyroid glands. Seven homeobox genes, namely HOXA4, HOXA5, HOXBAS3, HOXB4, HOXB6, HOXB9, IRX1, and one encoding for ALDH1A2 showed a lower expression in the inferior parathyroid glands than in the superior. Conversely, SLC6A1 showed a higher expression in the inferior glands. Of the nine genes with significant differential mRNA expression among superior and inferior glands HOXB9, HOXB4 and IRX1 could be detected by western blotting/mass spectrometry. The study is the first to show the differential expression of nine genes HOXA4, HOXA5, HOXBAS3, HOXB4, HOXB6, HOXB9, IRX1, ALDH1A2, and SLC6A1 in inferior versus the superior parathyroid glands. This could have potential implications for the preferential localization of parathyroid tumors to the inferior parathyroid glands as observed in patients with primary hyperparathyroidism.

Parathyroid hormone in situ measurement in patients with hyperparathyroidism: single-centre experience of 179 patients.

Context: The measurement of parathyroid hormone(PTH) in situ (PTHis) by fine-needle aspiration (FNA) has been proposed as a tool to preoperatively help localize parathyroid glands detected on ultrasound. However, the accuracy of PTHis is highly variable according to the few available studies. Aim: We aimed to develop and validate the PTHis procedure and assessed the performance of PTHis in a large series of patients with hyperparathyroidism and/or undetermined cervical lesions. Patients and methods: The technique set-up consisted of PTHis measurement in thyroid samples from patients with thyroid nodules and patients with high circulating PTH levels (tertiary hyperparathyroidism). Consecutive patients were recruited at one tertiary referral centre from 2017 to 2020 and submitted to ultrasound-guided FNA-PTHis determination. Results: During the method set-up, we obtained undetectable PTHis levels in all non-parathyroid tissues after sample dilutions. PTHis was higher in patients with hyperparathyroidism (n = 145; 1817 ± 3739 ng/L; range: <4.6-31 140) than in those with thyroid or undetermined cervical lesions (n= 34; <4.6 ng/mL; P < 0.0001). When evaluating PTHis performance in histologically proven samples (158 lesions from 121 patients), PTHis was detectable in 85/97 parathyroid lesions (87%; range: 22-31;140 ng/L) and undetectable in all non-parathyroid lesions (n = 61; P < 0.0001). The specificity and positive predictive value were 100%, and the sensitivity was 87.6%. False-negative lesions (n= 12) were smaller (9.4 ± 5.9 mm) and more often consisted of hyperplasias (75%) than true-positive lesions (16.1 ± 8.4 mm and 33%, P = 0.009 and P = 0.0089, respectively). The method was safe and well tolerated. Four educational cases are also provided. Conclusions: PTHis determination is a safe and well-tolerated procedure that enhances the specificity of ultrasound-detected lesions. If accurately set-up, it confirms the parathyroid origin of uncharacterized cervical lesions.

Characterization of Glycosphingolipids in the Human Parathyroid and Thyroid Glands.

As part of a systematic investigation of the glycosphingolipids in human tissues, acid and non-acid glycosphingolipids from human thyroid and parathyroid glands were isolated and characterized with mass spectrometry and binding of carbohydrate-recognizing ligands, with a focus on complex compounds. The glycosphingolipid patterns of the human parathyroid and thyroid glands were very similar. The major acid glycosphingolipids were sulfatide and the gangliosides GM3, GD3, GD1a, GD1b, GT1b and Neu5Ac-neolactotetraosylceramide, and the major non-acid glycosphingolipids were globotriaosylceramide and globoside. We also found neolactotetra- and neolactohexaosylceramide, the x2 glycosphingolipid, and complex glycosphingolipids with terminal blood group O and A determinants in both tissues. A glycosphingolipid with blood group Leb determinant was identified in the thyroid gland, and the parathyroid sample had a glycosphingolipid with terminal blood group B determinant. Immunohistochemistry demonstrated the expression of blood group A antigens in both the thyroid and parathyroid glands. A weak cytoplasmatic expression of the GD1a ganglioside was present in the thyroid, while the parathyroid gland had a strong GD1a expression on the cell surface. Thus, the glycosylation of human thyroid and parathyroid glands is more complex than previously appreciated. Our findings provide a platform for further studies of alterations of cell surface glycosphingolipids in thyroid and parathyroid cancers.

Local NF-κB Activation Promotes Parathyroid Hormone Synthesis and Secretion in Uremic Patients.

Secondary hyperparathyroidism (SHPT) in uremic patients is characterized by parathyroid gland (PTG) hyperplasia and parathyroid hormone (PTH) elevation. Previously, we demonstrated that NF-κB activation contributed to parathyroid cell proliferation in rats with chronic kidney disease. Although vitamin D inhibits inflammation and ameliorates SHPT, the contribution of vitamin D deficiency to SHPT via local NF-κB activation remains to be clarified. PTGs collected from 10 uremic patients with advanced SHPT were used to test the expressions of vitamin D receptor (VDR), NF-κB, and proliferating cell nuclear antigen (PCNA). Freshly excised PTG tissues were incubated for 24 hours in vitro with VDR activator (VDRA) calcitriol or NF-κB inhibitor pyrrolidine thiocarbamate (PDTC). Chromatin immunoprecipitation (ChIP) and luciferase reporter assays were performed to investigate the regulation of PTH transcription by NF-κB. We found higher levels of activated NF-κB and lower expression of VDR in nodular hyperplastic PTGs than in diffuse hyperplasia. In cultured PTG tissues, treatment with VDRA or PDTC inhibited NF-κB activation and PCNA expression, and downregulated preproPTH mRNA and intact PTH levels. ChIP assays demonstrated the presence of NF-κB binding sites in PTH promoter. Furthermore, in luciferase reporter assays, addition of exogenous p65 significantly increased PTH luciferase activity by 2.4-fold (P < 0.01), while mutation of NF-κB binding site at position -908 of the PTH promoter suppressed p65-induced PTH reporter activity (P < 0.01). In summary, local NF-κB activation contributes to SHPT and mediates the transcriptional activation of PTH directly in uremic patients. Vitamin D deficiency may be involved in SHPT via the activation of NF-κB pathway.

Environmental chemicals and metabolic disruption in primary and secondary human parathyroid tumors.

BACKGROUND: The incidence of primary hyperparathyroidism has increased 300% in the United States in the past 30 years, and secondary hyperparathyroidism is almost universal in patients with end-stage renal disease. We assessed the presence of environmental chemicals in human hyperplastic parathyroid tumors as possible contributing factors to this increase. METHODS: Cryopreserved hyperplastic parathyroid tumors and normal human parathyroids were analyzed by gas chromatography and liquid chromatography coupled to ultra-high-resolution mass spectrometry, bioinformatics, and biostatistics. RESULTS: Detected environmental chemicals included polychlorinated biphenyls, polybrominated diphenyl ethers, dichloro-diphenyl-trichloroethane derivatives, and other insecticides. A total of 99% had p,p'-dichlorodiphenyldichloroethylene. More than 50% contained other environmental chemicals, and many classified as endocrine disruptors. Polychlorinated biphenyl-28 and polychlorinated biphenyl-49 levels correlated positively with parathyroid tumor mass. Polybrominated diphenyl ether-47 concentrations in tumors were inversely correlated with patients' serum calcium levels. Cellular metabolites in pathways of purine and pyrimidine synthesis and mitochondrial energy production were associated with tumor growth and with p,p'-dichlorodiphenyldichloroethylene in primary hyperparathyroidism tumors. In normal parathyroids, p,p'-dichlorodiphenyldichloroethylene , polychlorinated biphenyl-28, polychlorinated biphenyl-74, and polychlorinated biphenyl-153, but not p,p'-dichlorodiphenyldichloroethylene or polychlorinated biphenyl-49, were detected. CONCLUSION: Environmental chemicals are present in human parathyroid tumors and warrant detailed epidemiologic and mechanistic studies to test for causal links to the growth of human parathyroid tumors.

[Uso de los valores de hormona paratiroidea intranodular obtenidos por punción con aguja fina como factor predictivo de hipoparatiroidismo posoperatorio]. / Use of intranodular parathyroid hormone values obtained by fine needle aspiration as a predictive factor of postoperative hypoparathyroidism.

OBJETIVO: Análisis de los valores de hormona paratiroidea (PTH) intranodular obtenidos por punción con aguja fina como factor predictivo de hipoparatiroidismo posoperatorio. MÉTODO: De los 157 pacientes a los que se realizó la medición de la PTH intranodular, se estudiaron 37 que fueron intervenidos quirúrgicamente, estableciendo 15 variables para analizar: edad, sexo, tiempo de evolución, tamaño, cirugía de tiroides asociada, tratamiento preoperatorio con calcimiméticos, litiasis renal, densitometría ósea, aclaramiento de creatinina, calcio y PTH preoperatorios, PTH determinada tras punción con aguja fina, descenso de la PTH intraoperatoria, calcio posoperatorio y malignidad de la tumoración. Estas se compararon con la prueba de ji al cuadrado o el test exacto de Fisher, siendo significativa una p < 0.05, construyéndose así un análisis de regresión logística. RESULTADOS: El uso de calcimiméticos previo a la cirugía, la PTH preoperatoria > 88 pg/dl, el calcio preoperatorio > 12 mg/dl, los valores de PTH intranodular > 2700 pg/dl, el descenso de la PTH intraoperatoria a < 15 pg/dl y el calcio posoperatorio < 8,5 mg/dl fueron variables independientes significativas en el análisis univariante (p < 0.05) para la predicción del hipoparatiroidismo posoperatorio. CONCLUSIONES: Los valores de PTH intranodular pueden predecir qué pacientes tienen mayor riesgo de sufrir un hipoparatiroidismo posoperatorio. Este factor debe tenerse en cuenta durante el estudio y el seguimiento de los pacientes para identificar precozmente posibles complicaciones. OBJECTIVE: To analize if parathyroid hormone (PTH) washout levels can be considered a predictive factor of postoperative hypoparathyroidism and determine its importance relative to other features already known as intraoperative PTH, Ca and PTH preoperative, and others. METHOD: Of the 157 patients to whom a fine needle aspiration (FNA) biopsy with intranodular parathyroid hormone level measurement was performed (washout PTH) 37 who underwent surgery were studied. 15 variables were taken into account when selecting patients for this study: age, gender, evolution length, size, associated thyroid surgery, preoperative treatment with calcimimetics, presence of renal lithiasis, bone densitometry alterations, creatine clearance, preoperative calcium and PTH levels, PTH scores obtained by fine needle aspiration, intraoperative PTH decrease, postoperative calcium levels and tumour malignancy. We compare the nominal values, using the Chi squared or the exact Fisher test, where p < 0.05 was considered statistically significant and perform a logistic regression analysis. RESULTS: The use of calcimimetics prior to surgery, the preoperative PTH level above 88 pg/dl, the preoperative calcium above 12 mg/dl, washout PTH above 2700 pg/dl, intraoperative PTH level decrease below 15 pg/dl, and postoperative calcium levels under 8.5 mg/dl were all independently significant variables in the univariant analysis (p < 0.05) in order to establish an early postoperative hypoparathyroidism. The rest of the variables were not statistically significative. CONCLUSION: The PTH washout levels can predict the appearance of postoperative hypoparathyroidism. This factor must be taken into account during the study and follow-up to identify possible complications and establish an adequate treatment on time.

5-Hydroxymethylcytosine discriminates between parathyroid adenoma and carcinoma.

BACKGROUND: Primary hyperparathyroidism is characterized by enlarged parathyroid glands due to an adenoma (80-85 %) or multiglandular disease (~15 %) causing hypersecretion of parathyroid hormone (PTH) and generally hypercalcemia. Parathyroid cancer is rare (<1-5 %). The epigenetic mark 5-hydroxymethylcytosine (5hmC) is reduced in various cancers, and this may involve reduced expression of the ten-eleven translocation 1 (TET1) enzyme. Here, we have performed novel experiments to determine the 5hmC level and TET1 protein expression in 43 parathyroid adenomas (PAs) and 17 parathyroid carcinomas (PCs) from patients who had local invasion or metastases and to address a potential growth regulatory role of TET1. RESULTS: The global 5hmC level was determined by a semi-quantitative DNA immune-dot blot assay in a smaller number of tumors. The global 5hmC level was reduced in nine PCs and 15 PAs compared to four normal tissue samples (p < 0.05), and it was most severely reduced in the PCs. By immunohistochemistry, all 17 PCs stained negatively for 5hmC and TET1 showed negative or variably heterogeneous staining for the majority. All 43 PAs displayed positive 5hmC staining, and a similar aberrant staining pattern of 5hmC and TET1 was seen in about half of the PAs. Western blotting analysis of two PCs and nine PAs showed variable TET1 protein expression levels. A significantly higher tumor weight was associated to PAs displaying a more severe aberrant staining pattern of 5hmC and TET1. Overexpression of TET1 in a colony forming assay inhibited parathyroid tumor cell growth. CONCLUSIONS: 5hmC can discriminate between PAs and PCs. Whether 5hmC represents a novel marker for malignancy warrants further analysis in additional parathyroid tumor cohorts. The results support a growth regulatory role of TET1 in parathyroid tissue.

Clinicopathological correlates of hyperparathyroidism.

Hyperparathyroidism is a common endocrine disorder with potential complications on the skeletal, renal, neurocognitive and cardiovascular systems. While most cases (95%) occur sporadically, about 5% are associated with a hereditary syndrome: multiple endocrine neoplasia syndromes (MEN-1, MEN-2A, MEN-4), hyperparathyroidism-jaw tumour syndrome (HPT-JT), familial hypocalciuric hypercalcaemia (FHH-1, FHH-2, FHH-3), familial hypercalciuric hypercalcaemia, neonatal severe hyperparathyroidism and isolated familial hyperparathyroidism. Recently, molecular mechanisms underlying possible tumour suppressor genes (MEN1, CDC73/HRPT2, CDKIs, APC, SFRPs, GSK3ß, RASSF1A, HIC1, RIZ1, WT1, CaSR, GNA11, AP2S1) and proto-oncogenes (CCND1/PRAD1, RET, ZFX, CTNNB1, EZH2) have been uncovered in the pathogenesis of hyperparathyroidism. While bi-allelic inactivation of CDC73/HRPT2 seems unique to parathyroid malignancy, aberrant activation of cyclin D1 and Wnt/ß-catenin signalling has been reported in benign and malignant parathyroid tumours. Clinicopathological correlates of primary hyperparathyroidism include parathyroid adenoma (80-85%), hyperplasia (10-15%) and carcinoma (<1-5%). Secondary hyperparathyroidism generally presents with diffuse parathyroid hyperplasia, whereas tertiary hyperparathyroidism reflects the emergence of autonomous parathyroid hormone (PTH)-producing neoplasm(s) from secondary parathyroid hyperplasia. Surgical resection of abnormal parathyroid tissue remains the only curative treatment in primary hyperparathyroidism, and parathyroidectomy specimens are frequently encountered in this setting. Clinical and biochemical features, including intraoperative PTH levels, number, weight and size of the affected parathyroid gland(s), are crucial parameters to consider when rendering an accurate diagnosis of parathyroid proliferations. This review provides an update on the expanding knowledge of hyperparathyroidism and highlights the clinicopathological correlations of this prevalent disease.

The vascular secret of Klotho.

Klotho is an evolutionarily highly conserved protein related to longevity. Increasing evidence of a vascular protecting effect of the Klotho protein has emerged and might be important for future treatments of uremic vascular calcification. It is still disputed whether Klotho is locally expressed in the vasculature or whether its vascular effects arise uniquely from its presence in the circulation.

Differential expression and regulation of Klotho by paricalcitol in the kidney, parathyroid, and aorta of uremic rats.

Klotho plays an important role in the pathogenesis of cardiovascular disease in chronic kidney disease (CKD). Klotho is highly expressed in the kidney and parathyroid glands, but its presence in the vasculature is debated. Renal Klotho is decreased in CKD, but the effect of uremia on Klotho in other tissues is not defined. The effect of vitamin D receptor activator therapy in CKD on the expression of Klotho in various tissues is also in debate. In uremic rats (surgical 5/6th nephrectomy model), we compared 3 months of treatment with and without paricalcitol on Klotho immunostaining in the kidney, parathyroid glands, and aorta. With uremia, Klotho was unchanged in the parathyroid, significantly decreased in the kidney (66%) and the intimal-medial area of the aorta (69%), and significantly increased in the adventitial area of the aorta (67%) compared with controls. Paricalcitol prevented the decrease of Klotho in the kidney, increased expression in the parathyroid (31%), had no effect in the aortic media, but blunted the increase of Klotho in the aortic adventitia. We propose that fibroblasts are responsible for the expression of Klotho in the adventitia. In hyperplastic human parathyroid tissue from uremic patients, Klotho was higher in oxyphil compared with chief cells. Thus, under our conditions of moderate CKD and mild-to-moderate hyperphosphatemia in rats, the differential expression of Klotho and its regulation by paricalcitol in uremia is tissue-dependent.

Utility of birefringent crystal identification by polarized light microscopy in distinguishing thyroid from parathyroid tissue on intraoperative frozen sections.

Differentiating parathyroid with pseudofollicular architecture from thyroid tissue can be challenging on intraoperative frozen sections. Birefringent calcium oxalate crystals are present in colloid of normal thyroid follicles, whereas crystals are rare in parathyroid tissue. It has been suggested that crystal identification using polarized microscopy could aid in distinguishing thyroid from parathyroid tissue on frozen sections when other ancillary studies are not available. However, the actual clinical utility of crystal detection on frozen sections has not been assessed. We reviewed all deferred or discrepant parathyroid versus thyroid intraoperative frozen section diagnoses over a 12.5-year period (17 cases). For comparison, we also reviewed 20 cases each of hypercellular parathyroid glands with pseudofollicular architecture, follicular adenomas, follicular carcinomas, follicular variant of papillary thyroid carcinomas, and nodular hyperplasias with a microfollicular pattern. These are diagnoses that could be difficult to differentiate tissue of origin (thyroid vs. parathyroid) on frozen section biopsies. Crystals were more common in thyroid (60/80) than in parathyroid (2/20) microfollicular/pseudofollicular lesions (75% vs. 10%, P<0.001). In 9 of 12 cases (75%) for which the frozen section was interpreted as or favored to be parathyroid but permanent sections showed only thyroid tissue, identification of crystals on the actual frozen section slides would have aided interpretation. This included 1 case of papillary thyroid carcinoma that was reimplanted into the patient's neck after a frozen section misdiagnosis of "parathyroid tissue" was made. We recommend examination of difficult follicular patterned parathyroid frozen sections by polarizing microscopy and deferring the diagnosis if crystals are found.

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.

[Fine-needle aspiration with measurement of parathyroid hormone levels in thyroidectomy].

OBJECTIVE: Hypoparathyroidism is one of the most serious complications of thyroidectomy. It is important to identify the parathyroid glands during thyroidectomy. In order to find an economic, simple and less traumatic way to identify the parathyroid glands and testify its feasibility, fine-needle aspiration of suspected parathyroid tissue was used to measure the parathyroid hormone (PTH) levels during the surgical procedure. METHODS: From Nov. 2011 to Apr. 2012, 50 patients were recruited for thyroid surgery in the Sun Yat-sen University Cancer Centre. During surgery, fine-needle aspiration of suspected tissues, including parathyroid gland, thyroid gland, muscle, fat tissue, and lymph node, was performed, the PTH levels were measured. In addition, the tissues above-mentioned were taken to pathological examination. Statistical processing was adopted to determine the sensitivity and specificity of intraoperative fine-needle aspiration with measurement of PTH level in finding the pathology of the parathyroid gland. RESULTS: There were 237 tissues from 50 patients in total, and 45 of them were certified as the parathyroid glands by pathology. Intra-operative PTH (ioPTH) of the tissues in forty-four cases were higher than 600 ng/L, ioPTH of the tissues in one case was lower than 600 ng/L, and it was 160 ng/L. The highest ioPTH in other cases was 537.7 ng/L. The sensitivity was 97.8%. The specificity was 100%. The difference between the sensitivity and the specificity of two groups was not statistically significant, and P > 0.05. The level of PTH of parathyroid gland were much higher than other tissues, and P < 0.001. CONCLUSIONS: The level of ioPTH of parathyroid gland were far higher than thyroid, muscle, fat, lymph node. It is an economic, fast and less traumatic way to identify the parathyroid gland by using the fine-needle aspiration of the parathyroid tissue with measurement of PTH levels. The sensitivity and the specificity are high. It can be used in the thyroidectomy to identify the parathyroid glands.

Morphological evaluation of parathyroid adenomas and immunohistochemical analysis of PCNA and Ki-67 proliferation markers.

OBJECTIVE: Parathyroid adenomas are the most common cause of primary hyperparathyroidism. Biological studies have shown that parathyroid adenomas are monoclonal proliferations. Up to date, five cell types have been identified in normal parathyroid tissues; chief cells, vacuolated chief cells, dark chief cells, oxyphil cells and transitional oxyphil cells. Most parathyroid adenomas are predominantly composed of chief cells. In this study, we aimed to indicate the relationship between the predominant cell type in parathyroid adenomas and proliferating cell nuclear antigen, Ki-67 antigen, and serum parathormone levels and the gland weight. MATERIAL AND METHOD: 15 cases who had a diagnosis of parathyroid adenomas were included in the study. Histopathologically, the predominant cell type was determined in all the cases. Paraffin blocks were immunohistochemically stained with proliferating cell nuclear antigen and Ki-67. RESULTS: The average parathormone level of the cases was 239.52 ± 36.61 pg/ml before surgery. Mean gland weight was 1.69 ± 0.49 g. Two of the cases showed atypical adenoma characteristics. The predominant cell type was vacuolated chief cell. Immunohistochemical investigation showed that the mean average Ki-67 index value was 4.26 ± 0.86%. The mean proliferating cell nuclear antigen index was 93.20± 45.72/10³. There was a meaningful relationship between gland weights and serum parathormone levels. There was no meaningful relationship between predominant cell types and serum parathormone levels, proliferating cell nuclear antigen index, and Ki-67 index. The chief cell was identified as the predominant cell type. CONCLUSION: It can be concluded that parathyroid adenomas come into existence as a result of neoplastic proliferation of chief cells, especially vacuolated chief cells.

Near-infrared autofluorescence for the detection of parathyroid glands.

A major challenge in endocrine surgery is the intraoperative detection of parathyroid glands during both thyroidectomies and parathyroidectomies. Current localization techniques such as ultrasound and sestamibi scan are mostly preoperative and rely on an abnormal parathyroid for its detection. In this paper, we present near-infrared (NIR) autofluorescence as a nonintrusive, real-time, automated in vivo method for the detection of the parathyroid gland. A pilot in vivo study was conducted to assess the ability of NIR fluorescence to identify parathyroid glands during thyroid and parathyroidectomies. Fluorescence measurements at 785 nm excitation were obtained intra-operatively from the different tissues exposed in the neck region in 21 patients undergoing endocrine surgery. The fluorescence intensity of the parathyroid gland was found to be consistently greater than that of the thyroid and all other tissues in the neck of all patients. In particular, parathyroid fluorescence was two to eleven times higher than that of the thyroid tissues with peak fluorescence occurring at 820 to 830 nm. These results indicate that NIR fluorescence has the potential to be an excellent optical tool to locate parathyroid tissue during surgery.

Study of parathyroid transcription factor Gcm2 expression in parathyroid lesions.

Glial cells missing 2 (Gcm2) is a master regulatory gene of parathyroid gland development, and it is exclusively expressed in the parathyroid gland. Diagnostic application of anti-Gcm2 antibody has not been reported yet. In this study, a total of 58 cases of parathyroid lesions including 40 adenomas, 2 atypical adenomas, 2 carcinomas, 9 hyperplastic lesions, 4 parathyroid cysts, and 1 case of recurrent hyperplasia of an autograft gland were stained with anti-Gcm2 antibody. Anti-Gcm2 was also applied to a variety of endocrine tumors, including thyroid tumors and nonendocrine tumors, and normal tissues from a variety of organs, including the parathyroid and thyroid glands. Gcm2 nuclear expression was seen in all the normal parathyroid glands, and cystic, hyperplastic, and neoplastic parathyroid lesions in a diffuse manner, whereas no Gcm2 expression was seen in any other normal tissues and tumors, including those of the thymus and thyroid gland. Anti-Gcm2 antibody is a highly sensitive and specific marker for parathyroid lesions. Although the immunohistochemistry stain for parathyroid hormone is a useful marker, its reaction tends to be variable in extent and intensity in parathyroid neoplasia, and it is often negative in parathyroid cysts, and Gcm2 would serve as a useful adjunct marker.

A proteomic approach to study parathyroid glands.

Parathyroid tumours are heterogeneous and in some cases the diagnosis may be difficult using histological features. In this study we used a two-dimensional electrophoresis (2D)/mass spectrometry (MS)-based approach to examine the global changes of parathyroid adenoma tissues protein profile compared to the parathyroid normal tissues. Validation of protein expression was performed by immunoblotting using specific antibodies. Ingenuity software was used to identify the biological processes to which these proteins belong and to construct a potential network. A total of 30 proteins were found to be differentially expressed, of which 22 resulted in being over-expressed. Proteins identified by 2D/MS/MS proteomics were classified into functional categories and a major change (≥ 2-fold) in terms of expression was found in proteins involved in response to biotic stimuli, cell organization and signal transduction. After Ingenuity analysis, 14-3-3 ζ/δ appears to be a key protein in the network of parathyroid adenoma, where it is linked to other proteins such as annexin A2, B box and SPRY domain-containing protein (BSPRY), p53 and epidermal growth factor receptor (EGFR). Our results suggest that the proteomic approach was able to differentiate the protein profiles of normal parathyroid and parathyroid adenoma and identify a panel of proteins which are differentially expressed. The functional role of these proteins in the network of intracellular pathways is discussed.

The number of needle passes affects the accuracy of parathyroid hormone assay with intraoperative parathyroid aspiration.

INTRODUCTION: Intraoperative aspiration of a nodule and parathyroid hormone (PTH) assay has been shown to accurately confirm parathyroid tissue. However, the reported aspiration technique varies in the literature. We sought to determine if the number of passes affected the accuracy of PTH analysis. METHODS: A prospective analysis was performed on 25 consecutive patients who underwent a parathyroidectomy for primary hyperparathyroidism. The excised parathyroid gland was aspirated using 1, 3, and 5 passes. The data were analyzed using the Wilcoxon rank, chi-square, and Fisher exact tests to calculate the 2-tailed P value. RESULTS: Of the 26 glands aspirated, the mean PTH value varied with the number of passes, 2,073 pg/mL for 1 pass, 2,347 for 3 passes, and 2,695 for 5 passes (P = .02). Accuracy was dependent on the number of passes, with 5 passes (P = .018) having less PTH variation than 1 or 3 passes. CONCLUSIONS: Aspiration of nodules to determine the PTH level helps confirm the presence of parathyroid tissue. The number of needle passes affects the accuracy of the PTH level, with 5 passes being the optimal number of passes to attain no false-negative results.

Rapid intraoperative parathyroid hormone assay in fine needle aspiration for differential diagnosis in thyroid and parathyroid surgery.

BACKGROUND: The purpose of our study was to investigate the efficacy of rapid intraoperative parathyroid hormone (rIO-PTH) analysis performed using material collected by fine needle aspiration as a parameter to distinguish anatomical structures which the surgeon is not able to identify clearly as parathyroid or lymph node during thyroid/parathyroid surgery. Before surgery, all patients gave written, informed consent. METHODS: We measured the rIO-PTH on 50 anatomical structures, 32 presumed parathyroids and 18 presumed lymph nodes from 22 patients, who underwent thyroid/parathyroid surgery between May and September 2009. RESULTS: The rIO-PTH values obtained on parathyroids ranged from 85.4 pmol/L to more than 2106 pmol/L, with a rIO-PTH median of 263.25 pmol/L. Results obtained on lymph nodes ranged from <0.52 pmol/L up to 20.4 pmol/L, with a rIO-PTH median equal to 1.31 pmol/L. Results of the Mann-Whitney test showed a rIO-PTH median significantly different (p<0.0001) between samples obtained from parathyroid glands and lymph node tissue. CONCLUSIONS: We demonstrated that rapid intraoperative measurement of parathyroid hormone is a good parameter for the differential diagnosis of parathyroid vs. lymph node tissue. We suggest extending the use of this technique to the field of parathyroid preservation during thyroid/parathyroid surgery in those cases where the parathyroids prove difficult to recognize on the basis of topographic or morphologic criteria.

[High retention of (99m)Tc-MIBI in delayed phase as a pitfall in the combined parathyroid-thyroid scintigraphy]. / Intensa retención de (99m)Tc-MIBI en la fase tardía como causa de error diagnóstico en la gammagrafía combinada paratiroides-tiroides.

Dual phase parathyroid scintigraphy with (99m)Tc-sestaMIBI is a very sensitive technique in the preoperative localization and diagnosis of parathyroid adenoma. However, pitfalls have been reported in patients with thyroid nodules with MIBI uptake or with previous thyroid surgery. To solve this problem, a thyroid scintigraphy with (99m)Tc-pertechnetate is usually performed following the parathyroid study. Occasionally, as in our patient the parathyroid lesion may show high MIBI uptake and delayed washout that interfere with the subsequent thyroid scintigraphy giving the false appearance of a pertechnetate avid lesion. This has been called the «shine through¼ effect. To avoid it, the parathyroid and thyroid scintigraphies can be performed on separate days. We have also found it useful to compare our results with that of ultrasound and fine needle aspiration puncture with measurement of the parathyroid hormone (PTH) and thyroglobulin in the aspirated material.