Parathyroid Hormone Secretion Research Articles

Metabolic syndrome in parathyroid diseases

Metabolic syndrome is a cluster of metabolic abnormalities, including central obesity, insulin resistance, dyslipidemia, and hypertension. Parathyroid diseases are a group of disorders that affect the parathyroid glands’ function, which regulates the body’s calcium and phosphorus levels. There is growing evidence that parathyroid diseases may be associated with metabolic syndrome. There is a growing body of evidence suggesting a possible association between parathyroid diseases and metabolic syndrome. Hyperparathyroidism and secondary hyperparathyroidism are associated with insulin resistance and dyslipidemia, while hypoparathyroidism is associated with hypocalcemia-induced metabolic abnormalities. Further studies are needed better to understand the relationship between parathyroid diseases and metabolic syndrome and to develop effective treatment strategies. Hyperparathyroidism is a common parathyroid disease characterized by excessive secretion of parathyroid hormone (PTH). Parathormone plays a crucial role in calcium homeostasis and bone metabolism. However, excessive PTH secretion can lead to hypercalcemia, which can cause metabolic abnormalities such as insulin resistance and dyslipidemia. Studies have shown that patients with primary hyperparathyroidism have a higher metabolic syndrome prevalence than the general population. Secondary hyperparathyroidism is another parathyroid disease in patients with chronic renal failure. Chronic kidney disease leads to impaired renal function, which results in decreased vitamin D synthesis and increased PTH secretion. Secondary hyperparathyroidism is associated with bone mineral disorders and cardiovascular disease. Studies have also shown that secondary hyperparathyroidism is associated with metabolic abnormalities such as insulin resistance and dyslipidemia.

Construction of a circRNA- lincRNA-lncRNA-miRNA-mRNA ceRNA regulatory network identifies genes and pathways linked to goat fertility.

Background: There is growing interest in the genetic improvement of fertility traits in female goats. With high-throughput genotyping, single-cell RNA sequencing (scRNA-seq) is a powerful tool for measuring gene expression profiles. The primary objective was to investigate comparative transcriptome profiling of granulosa cells (GCs) of high- and low-fertility goats, using scRNA-seq. Methods: Thirty samples from Ji'ning Gray goats (n = 15 for high fertility and n = 15 for low fertility) were retrieved from publicly available scRNA-seq data. Functional enrichment analysis and a literature mining approach were applied to explore modules and hub genes related to fertility. Then, interactions between types of RNAs identified were predicted, and the ceRNA regulatory network was constructed by integrating these interactions with other gene regulatory networks (GRNs). Results and discussion: Comparative transcriptomics-related analyses identified 150 differentially expressed genes (DEGs) between high- and low-fertility groups, based on the fold change (≥5 and ≤-5) and false discovery rate (FDR <0.05). Among these genes, 80 were upregulated and 70 were downregulated. In addition, 81 mRNAs, 58 circRNAs, 8 lincRNAs, 19 lncRNAs, and 55 miRNAs were identified by literature mining. Furthermore, we identified 18 hub genes (SMAD1, SMAD2, SMAD3, SMAD4, TIMP1, ERBB2, BMP15, TGFB1, MAPK3, CTNNB1, BMPR2, AMHR2, TGFBR2, BMP4, ESR1, BMPR1B, AR, and TGFB2) involved in goat fertility. Identified biological networks and modules were mainly associated with ovary signature pathways. In addition, KEGG enrichment analysis identified regulating pluripotency of stem cells, cytokine-cytokine receptor interactions, ovarian steroidogenesis, oocyte meiosis, progesterone-mediated oocyte maturation, parathyroid and growth hormone synthesis, cortisol synthesis and secretion, and signaling pathways for prolactin, TGF-beta, Hippo, MAPK, PI3K-Akt, and FoxO. Functional annotation of identified DEGs implicated important biological pathways. These findings provided insights into the genetic basis of fertility in female goats and are an impetus to elucidate molecular ceRNA regulatory networks and functions of DEGs underlying ovarian follicular development.

Metabolism of parathyroid organoids.

We successfully developed a broad spectrum of patient-derived endocrine organoids (PDO) from benign and malignant neoplasms of thyroid, parathyroid, and adrenal glands. In this study, we employed functionally intact parathyroid PDOs from benign parathyroid tissues to study primary hyperparathyroidism (PHPT), a common endocrine metabolic disease. As proof of concept, we examined the utility of parathyroid PDOs for bioenergetic and metabolic screening and assessed whether parathyroid PDO metabolism recapitulated matched PHPT tissues. Our study methods included a fine-needle aspiration (FNA)-based technique to establish parathyroid PDOs from human PHPT tissues (n=6) in semi-solid culture conditions for organoid formation, growth, and proliferation. Mass spectrometry metabolomic analysis of PHPT tissues and patient-matched PDOs, and live cell bioenergetic profiling of parathyroid PDOs with extracellular flux analyses, were performed. Functional analysis cryopreserved and re-cultured parathyroid PDOs for parathyroid hormone (PTH) secretion was performed using ELISA hormone assays. Our findings support both the feasibility of parathyroid PDOs for metabolic and bioenergetic profiling and reinforce metabolic recapitulation of PHPT tissues by patient-matched parathyroid PDOs. Cryopreserved parathyroid PDOs exhibited preserved, rapid, and sustained secretory function after thawing. In conclusion, successful utilization of parathyroid PDOs for metabolic profiling further affirms the feasibility of promising endocrine organoid platforms for future metabolic studies and broader multiplatform and translational applications for therapeutic advancements of parathyroid and other endocrine applications.

Cellular and molecular mechanisms of the organogenesis and development, and function of the mammalian parathyroid gland.

Serum calcium homeostasis is mainly regulated by parathormone (PTH) secreted by the parathyroid gland. Besides PTH and Gcm2, a master gene for parathyroid differentiation, many genes are expressed in the gland. Especially, calcium-sensing receptor (CaSR), vitamin D receptor (VDR), and Klotho function to prevent increased secretion of PTH and hyperplasia of the parathyroid gland under chronic hypocalcemia. Parathyroid-specific dual deletion of Klotho and CaSR induces a marked enlargement of the glandular size. The parathyroid develops from the third and fourth pharyngeal pouches except murine species in which the gland is derived from the third pouch only. The development of the murine parathyroid gland is categorized as follows: (1) formation and differentiation of the pharyngeal pouches, (2) appearance of parathyroid domain in the third pharyngeal pouch together with thymus domain, (3) migration of parathyroid primordium attached to the top of thymus, and (4) contact with the thyroid lobe and separation from the thymus. The transcription factors and signaling molecules involved in each of these developmental stages are elaborated. In addition, mesenchymal neural crest cells surrounding the pharyngeal pouches and parathyroid primordium and invading the parathyroid parenchyma participate in the development of the gland.

The vitamin D receptor in osteoblastic cells but not secreted parathyroid hormone is crucial for soft tissue calcification induced by the proresorptive activity of 1,25(OH)2D3

The vitamin D receptor (VDR) is expressed most abundantly in osteoblasts and osteocytes (osteoblastic cells) in bone tissues and regulates bone resorption and calcium (Ca) and phosphate (P) homeostasis in association with parathyroid hormone (PTH). We previously reported that near-physiological doses of vitamin D compounds suppressed bone resorption through VDR in osteoblastic cells. We also found that supra-physiological doses of 1α,25-dihydroxyvitamin D3 [1,25(OH)2D3] induced bone resorption and hypercalcemia via VDR in osteoblastic cells. Here, we report that the latter, a proresorptive dose of 1,25(OH)2D3, causes soft tissue calcification through VDR in osteoblastic cells. High concentrations of vitamin D affect multiple organs and cause soft tissue calcification, with increases in bone resorption and serum Ca levels. Such a variety of symptoms is known as hypervitaminosis D, which is caused by not only high doses of vitamin D but also impaired vitamin D metabolism and diseases that produce 1,25(OH)2D3 ectopically. To clarify the biological process hierarchy in hypervitaminosis D, a proresorptive dose of 1,25(OH)2D3 was administered to wild-type mice in which bone resorption had been suppressed by neutralizing anti-receptor activator of NF-κB ligand (RANKL) antibody. 1,25(OH)2D3 upregulated the serum Ca x P product, concomitantly induced calcification of the aorta, lungs, and kidneys, and downregulated serum PTH levels in control IgG-pretreated wild-type mice. Pretreatment of wild-type mice with anti-RANKL antibody did not affect the down-regulation of PTH levels by 1,25(OH)2D3, but inhibited the increase of the serum Ca x P product and soft tissue calcification induced by 1,25(OH)2D3. Consistent with the effects of anti-RANKL antibody, VDR ablation in osteoblastic cells also did not affect the down-regulation of PTH levels by 1,25(OH)2D3, but suppressed the 1,25(OH)2D3-induced increase of the serum Ca x P product and calcification of soft tissues. Taken together with our previous results, these findings suggest that bone resorption induced by VDR signaling in osteoblastic cells is critical for the pathogenesis of hypervitaminosis D, but PTH is not involved in hypervitaminosis D.

Robotic resection of ectopic mediastinal parathyroid adenoma in multiple endocrine neoplasia 1

BackgroundHyperparathyroidism in patients with multiple endocrine neoplasia 1 is attributed to the excessive secretion of parathyroid hormone (PTH) from multiple parathyroid glands. This can be successfully treated through complete resection of the parathyroid glands; however, subsequent surgery is often required because of the presence of supernumerary or ectopic parathyroid glands. Therefore, identifying the locations of all functional glands is crucial for precise resection. Here, we report a case of ectopic mediastinal parathyroid adenoma that was successfully resected using robot-assisted thoracoscopic surgery.Case presentationA 53-year-old woman underwent a total parathyroidectomy with autotransplantation for multiple endocrine neoplasia 1-associated primary hyperparathyroidism. The patient previously underwent laparoscopic distal pancreatectomy for a pancreatic neuroendocrine tumor. She also presented with a mediastinal tumor and nonfunctional pituitary adenoma that could be followed up. Blood tests before total parathyroidectomy showed high levels of intact PTH (183 pg/mL) and calcium (Ca; 10.3 mg/dL); however, postoperative blood tests still revealed high levels of intact PTH (103 pg/mL) and Ca (11.4 mg/dL). Computed tomography and magnetic resonance imaging revealed a 45-mm-sized mass in the right upper mediastinum as a well-defined solid and cystic lesion, whereas 99mTc-methoxyisobutylisonitrile scintigraphy indicated a strong accumulation of tracers, suggesting an ectopic lesion in the mediastinum. Persistent hyperparathyroidism after total parathyroidectomy via neck incision was attributed to an ectopic parathyroid tumor in the mediastinum. Thus, we decided to resect the tumor using robot-assisted thoracoscopic surgery to perform the procedure gently and carefully. During surgery, a mediastinal tumor was identified as it was detected radiographically. Because it did not invade the surrounding tissues, it could be completely resected without injuring the capsule. The patient was discharged without complications. Postoperatively, Ca and intact PTH levels decreased back to normal. The final pathological diagnosis confirmed that the mass was an ectopic mediastinal parathyroid adenoma.ConclusionsMinimally invasive surgical resection of a remnant ectopic lesion was successfully performed in a patient with multiple endocrine neoplasia 1 using robot-assisted thoracoscopic surgery.

High sodium promotes the secretion and synthesis of PTH through PiT-1-IKKβ pathway in parathyroid gland in vitro.

Parathyroid hormone (PTH) is secreted by the parathyroid glands (PTGs) and is an important hormone regulating mineral metabolism. Previous studies reported that high sodium diet will cause the increase in serum PTH, but the specific mechanism is unknown. Consequently, the present study aims to investigate the effects and mechanisms of high sodium on PTH synthesis and secretion from PTGs. We developed a tissue culture model using normal rat PTGs, discovered that sodium elicited and promoted concentration-dependent and time-dependent PTH secretion. Changes in sodium-associated transporters from PTGs incubated with high sodium were thoroughly examined. Increased expression of sodium-phosphate cotransporter Slc20a1 (also known as PiT-1) was observed. Further tests revealed that PiT-1 activated the NF-κB signaling pathway, resulting in increased IKKβ phosphorylation, IKBα degradation, and increased p65 phosphorylation followed by nuclear entry, which led to increased PTH transcription. Meanwhile, IKKβ phosphorylated SNAP23, promoting exocytosis and eventually led to increased PTH secretion. In conclusion, our findings indicate that PiT-1 plays an important role in the increased secretion and synthesis of PTH directly induced by high sodium under physiological conditions, and may provide a potential therapeutic target for secondary hyperparathyroidism (SHPT).

Preservation of parathyroid glands during thyroid and neck surgery.

The parathyroid glands are situated in close proximity to the thyroid gland. They have an important endocrine function maintaining calcium and phosphate homeostasis in the body by the secretion of parathormone (PTH), which is responsible for this function. The parathyroid glands are commonly damaged during thyroid surgeries. This could lead to transient or permanent hypoparathyroidism in 30% of cases. Preservation of the parathyroid glands, is an important and integral part of thyroidectomy and other surgical interventions in the neck. The main principle underlying this is a thorough understanding of parathyroid anatomy in relation to the thyroid gland and other important structures in the area. There can also be significant variation in the anatomical location of the glands. Various techniques and methods have been described for parathyroid preservation. They include intraoperative identification utilizing indocyanine green (ICG) fluorescence, carbon nanoparticles, loupes, and microscopes. The techniques of surgery (meticulous capsular dissection), expertise, central compartment neck dissection, preoperative vitamin D deficiency, extent and type of thyroidectomy are the risk factors associated with damaged thyroids, inadvertent parathyroidectomy and subsequent hypoparathyroidism. Parathyroid Autotransplantation is a treatment option for inadvertent parathyroidectomy. Ultimately, the best way to assure normal parathyroid function is to preserve them in situ intraoperatively undamaged.

Dentoalveolar Alterations in an Adenine-Induced Chronic Kidney Disease Mouse Model.

Chronic kidney disease (CKD) is characterized by kidney damage and loss of renal function. CKD mineral and bone disorder (CKD-MBD) describes the dysregulation of mineral homeostasis, including hyperphosphatemia and elevated parathyroid hormone (PTH) secretion, skeletal abnormalities, and vascular calcification. CKD-MBD impacts the oral cavity, with effects including salivary gland dysfunction, enamel hypoplasia and damage, increased dentin formation, decreased pulp volume, pulp calcifications, and altered jaw bones, contributing to clinical manifestations of periodontal disease and tooth loss. Underlying mechanisms are not fully understood, and CKD mouse models commonly require invasive procedures with high rates of infection and mortality. We aimed to characterize the dentoalveolar effects of an adenine diet (AD)-induced CKD (AD-CKD) mouse model. Eight-week-old C57BL/6J mice were provided either a normal phosphorus diet control (CTR) or adenine and high-phosphorus diet CKD to induce kidney failure. Mice were euthanized at 15 weeks old, and mandibles were collected for micro-computed tomography and histology. CKD mice exhibited kidney failure, hyperphosphatemia, and hyperparathyroidism in association with porous cortical bone in femurs. CKD mice showed a 30% decrease in molar enamel volume compared to CTR mice. Enamel wear was associated with reduced ductal components, ectopic calcifications, and altered osteopontin (OPN) deposition in submandibular salivary glands of CKD mice. Molar cusps in CKD mice were flattened, exposing dentin. Molar dentin/cementum volume increased 7% in CKD mice and pulp volume decreased. Histology revealed excessive reactionary dentin and altered pulp-dentin extracellular matrix proteins, including increased OPN. Mandibular bone volume fraction decreased 12% and bone mineral density decreased 9% in CKD versus CTR mice. Alveolar bone in CKD mice exhibited increased tissue-nonspecific alkaline phosphatase localization, OPN deposition, and greater osteoclast numbers. AD-CKD recapitulated key aspects reported in CKD patients and revealed new insights into CKD-associated oral defects. This model has potential for studying mechanisms of dentoalveolar defects or therapeutic interventions. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Submandibular Ectopic Parathyroid Adenoma: A Case Report.

Primary hyperparathyroidism (PHPT) is a common endocrine disorder characterized by hypercalcemia and elevated or abnormally normal parathyroid hormone (PTH) levels, due to excessive secretion of PTH by 1 or more parathyroid glands. In this report, we discuss the diagnostic and therapeutic challenges posed by ectopic parathyroid adenomas, a rare but atypical presentation of PHPT. We present the case of a 36-year-old female with PHPT due to an ectopic parathyroid adenoma located in the submandibular region. The patient presented with bone pain and was initially evaluated with routine imaging studies, which were negative. [18F] F-choline positron emission tomography (PET)/Computed tomography revealed the ectopic adenoma, leading to successful surgical management. Ectopic parathyroid adenomas are rare but can occur in various locations, and functional imaging modalities such as choline PET can aid in their detection. Surgical resection remains the definitive treatment for parathyroid adenomas, with intraoperative PTH monitoring guiding the extent of resection. Proper evaluation and management of PHPT is essential to avoid significant morbidity. Our case adds to the growing body of literature on the importance of considering ectopic locations of parathyroid adenomas in patients with PHPT.

Parathyroid cyst-An unusual presentation

Parathyroid cyst is one of the least common causes of neck and mediastinal mass and often mistaken be thyroid cyst. Despite advancement in radiological and cytological investigations diagnosing a parathyroid cyst had always been a clinical challenge and mistaken for thyroid pathology and it is only diagnosed during histopathological examination post-surgical resection. The pathogenesis of parathyroid cyst includes the embryological remnant of the 3 or 4 branchial arch with accumulation of colloid material within it. These are classified into functioning and non -functioning depending on whether they are secreting parathyroid hormone and resulting in hypercalcemia. Surgery is indicated in all functioning Parathyroid cysts to alleviate the symptoms of hypercalcemia, larger Parathyroid cysts, and recommended in Parathyroid cysts that recur following more conservative approaches.

Establishment and characterization of long-term human primary parathyroid tumor subclones derived from Indian PHPT.

The continuous cell line of epithelial human parathyroid cells has been proven difficult. Previously, PTH-C1 cell line was only established rat parathyroid tissue cell line known to express the parathyroid hormone-related peptide (Pthrp) gene. The paucity of continuous cell line of human parathyroid cells secreting parathyroid hormone (PTH) has imposed hurdle in in vitro assessment of the mechanisms involved in the control of parathyroid cell function and proliferation. The primary cell cultures of human parathyroid cells were derived from parathyroid adenoma tissue biopsy (n = 5). The cells were subsequently subcultured to maintained primary subclones. Karyotyping analysis was performed to analyze the genotypic identity of derived subclones. The expression of calcium-sensing receptor (CaSR) and intact parathyroid hormone (iPTH) were analyzed using immunocytochemistry and immunofluorescence. In the present study, we have used a defined condition medium to generate the continuous culture of human parathyroid cells derived from patients with parathyroid adenoma due to primary hyperparathyroidism. The subcultured primary subclones were maintained epithelial and polygonal morphology, doubling time of approximately 25h, displaying a diploid chromosome number, and secretion of PTH. This cell line produces PTH and expresses the calcium-sensing receptor (CaSR) known to be involved in parathyroid function. Altogether these findings indicate the uniqueness of the human parathyroid cell line as an in vitro model for cellular and molecular studies on parathyroid physiopathology.

3D printed hydrogel scaffold promotes the formation of hormone-active engineered parathyroid tissue

The parathyroid glands are localized at the back of the thyroid glands in the cervical region and are responsible for regulation of the calcium level in the blood, through specialized cells that sense Ca2+ and secrete parathyroid hormone (PTH) in response to a decline in its serum level. PTH stimulates the skeleton, kidneys and intestines and controls the level of Ca2+ through specialized activities. Iatrogenic removal of the parathyroid gland, as well as damage to its vascular integrity during cauterization are some of the common complications of thyroid surgery. Therefore, regeneration and/or replacement of malfunctioning parathyroid tissue is required. Tissue engineering is an emerging and promising field for patients with organ failure with recent pioneering clinical applications. The success of tissue engineering strategy depends on the use of proper cells, bioactive factors that stimulate the activities of these cells and scaffolds that are produced to recapitulate the tissue structure and support the function of the engineered tissues. 3D printing is a developing strategy for the production of these scaffolds by providing a delicate control over their structure and properties. In this study, human primary parathyroid cells were successfully isolated and their viability and ability to secrete PTH upon stimulation with different levels of Ca2+ were shown in vitro. These cells were then seeded onto 3D printed alginate scaffolds and 3D bioprinted within alginate bioink, and cell viability as well as the ability to secrete PTH upon stimulation were also demonstrated. Therefore, functional hormone-active parathyroid tissue substitute was engineered in vitro through 3D printed hydrogels and autologous cells.

Transcriptome Analysis Identifies Tumor Immune Microenvironment Signaling Networks Supporting Metastatic Castration-Resistant Prostate Cancer.

Prostate cancer (PCa) is the second most common cause of cancer death in American men. Metastatic castration-resistant prostate cancer (mCRPC) is the most lethal form of PCa and preferentially metastasizes to the bones through incompletely understood molecular mechanisms. Herein, we processed RNA sequencing data from patients with mCRPC (n = 60) and identified 14 gene clusters (modules) highly correlated with mCRPC bone metastasis. We used a novel combination of weighted gene co-expression network analysis (WGCNA) and upstream regulator and gene ontology analyses of clinically annotated transcriptomes to identify the genes. The cyan module (M14) had the strongest positive correlation (0.81, p = 4 × 10-15) with mCRPC bone metastasis. It was associated with two significant biological pathways through KEGG enrichment analysis (parathyroid hormone synthesis, secretion, and action and protein digestion and absorption). In particular, we identified 10 hub genes (ALPL, PHEX, RUNX2, ENPP1, PHOSPHO1, PTH1R, COL11A1, COL24A1, COL22A1, and COL13A1) using cytoHubba of Cytoscape. We also found high gene expression for collagen formation, degradation, absorption, cell-signaling peptides, and bone regulation processes through Gene Ontology (GO) enrichment analysis.

Inhibition of the calcium-sensing receptor by extracellular phosphate ions and by intracellular phosphorylation.

As both a sensor of extracellular calcium (Ca2+ o) concentration and a key controller of Ca2+ o homeostasis, one of the most interesting properties of the calcium-sensing receptor (CaR) is its sensitivity to, and modulation by, ions and small ligands other than Ca2+. There is emerging evidence that extracellular phosphate can act as a partial, non-competitive CaR antagonist to modulate parathyroid hormone (PTH) secretion, thus permitting the CaR to integrate mineral homeostasis more broadly. Interestingly, phosphorylation of certain intracellular CaR residues can also inhibit CaR responsiveness. Thus, negatively charged phosphate can decrease CaR activity both extracellularly (via association with arginine) and intracellularly (via covalent phosphorylation).

Effects of PTH glandular and external dosing patterns on bone cell activity using a two-state receptor model-Implications for bone disease progression and treatment.

Temporal aspects of ligand specificity have been shown to play a significant role in the case of pulsatile hormone secretion, as exemplified by parathyroid hormone (PTH) binding to its receptor (PTH1R), a G-protein-coupled receptor expressed on surfaces of osteoblasts and osteocytes. The latter binding reaction regulates intracellular signalling and subsequently modulates skeletal homeostasis via bone remodelling. PTH glandular secretion patterns dictate bone cellular activity. In healthy humans, 70% of PTH is secreted in a tonic fashion, whereas 30% is secreted in low-amplitude and high-frequency bursts occurring every 10-20 min, superimposed on the tonic secretion. Changes in the PTH secretion patterns have been associated with various bone diseases. In this paper, we analyse PTH glandular secretion patterns for healthy and pathological states and their link to bone cellular responsiveness (αR). We utilise a two-state receptor ligand binding model of PTH to PTH1R together with a cellular activity function which is able to distinguish various aspects of the stimulation signal including peak dose, time of ligand exposure, and exposure period. Formulating and solving several constrained optimisation problems, we investigate the potential of pharmacological manipulation of the diseased glandular secretion and via clinical approved external PTH injections to restore healthy bone cellular responsiveness. Based on the mean experimentally reported data, our simulation results indicate cellular responsiveness in healthy subjects is sensitive to the tonic baseline stimulus and it is 28% of the computed maximum responsiveness. Simulation results for pathological cases of glucocorticoid-induced osteoporosis, hyperparathyroidism, initial and steady state hypocalcemia clamp tests indicate αR values significantly larger than the healthy baseline (1.7, 2.2, 4.9 and 1.9-times, respectively). Manipulation of the pulsatile glandular secretion pattern, while keeping the mean PTH concentration constant, allowed restoration of healthy baseline values from these catabolic bone diseases. Conversely, PTH glandular diseases that led to maximum bone cellular responsiveness below the healthy baseline value can't be restored to baseline via glandular manipulation. However, external PTH injections allowed restoration of these latter cases.

Brown tumor of the rib associated with primary hyperparathyroidism misdiagnosed as metastatic deposit - A case report

Brown tumor is a rare skeletal manifestation where multiple giant cell rich bony lesions, arise as a direct result of either primary or secondary hyperparathyroidism. It is caused by excess osteoclastic activity and hemosiderin deposition because of uncontrolled parathormone secretion. Brown tumors usually involve mandible, maxilla, clavicle, ribs, and pelvic bones. Our case report describes the case of a 42-year-old lady who consulted our hospital for multiple bony lesions in ribs suspicious of metastasis and summarizes our experience in diagnosis of similar cases that we might come across in the future.

Digital spatial profiling of human parathyroid tumors reveals cellular and molecular alterations linked to vitamin D deficiency.

Primary hyperparathyroidism (PHPT) is a common endocrine neoplastic disorder characterized by disrupted calcium homeostasis secondary to inappropriately elevated parathyroid hormone (PTH) secretion. Low levels of serum 25-hydroxyvitamin D (25OHD) are significantly more prevalent in PHPT patients than in the general population (1-3), but the basis for this association remains unclear. We employed a spatially defined in situ whole-transcriptomics and selective proteomics profiling approach to compare gene expression patterns and cellular composition in parathyroid adenomas from vitamin D-deficient or vitamin D-replete PHPT patients. A cross-sectional panel of eucalcemic cadaveric donor parathyroid glands was examined in parallel as normal tissue controls. Here, we report that parathyroid tumors from vitamin D-deficient PHPT patients (Def-Ts) are intrinsically different from those of vitamin D-replete patients (Rep-Ts) of similar age and preoperative clinical presentation. The parathyroid oxyphil cell content is markedly higher in Def-Ts (47.8%) relative to Rep-Ts (17.8%) and normal donor glands (7.7%). Vitamin D deficiency is associated with increased expression of electron transport chain and oxidative phosphorylation pathway components. Parathyroid oxyphil cells, while morphologically distinct, are comparable to chief cells at the transcriptional level, and vitamin D deficiency affects the transcriptional profiles of both cell types in a similar manner. These data suggest that oxyphil cells are derived from chief cells and imply that their increased abundance may be induced by low vitamin D status. Gene set enrichment analysis reveals that pathways altered in Def-Ts are distinct from Rep-Ts, suggesting alternative tumor etiologies in these groups. Increased oxyphil content may thus be a morphological indicator of tumor-predisposing cellular stress.

Immunohistochemical characterization of a steroid secreting oncocytic adrenal carcinoma responsible for paraneoplastic hyperparathyroidism.

We report a unique case of a 44-year-old man with paraneoplastic hyperparathyroidism due to an oncocytic adrenocortical carcinoma (stage pT3N0R0M0, ENSAT 2 with a 4% Ki-67). Paraneoplastic hyperparathyroidism was associated with mild ACTH-independent hypercortisolism and increased estradiol secretion responsible for gynecomastia and hypogonadism. Biological investigations performed in blood samples from peripheral and adrenal veins revealed that the tumor secreted PTH and estradiol. Ectopic PTH secretion was confirmed by abnormally high expression of PTH mRNA and clusters of PTH immunoreactive cells in the tumor tissue. Double-immunochemistry studies and analysis of contiguous slides for the expression of PTH and steroidogenic markers (SRB-1, 3β-HSD and aromatase) were performed. The results suggested the presence of two tumor cells subtypes with large cells with voluminous nuclei producing only PTH and that were distinct from steroid producing cells.

What do we know about lithium associated hypercalcemia?

IntroductionLithium associated with hypercalcemia may mimic a psychiatric condition and be confused for a relapse of bipolar disorder. The etiology seems to be due to a reduced sensitivity of the parathyroid cells to calcium, altering the parathyroid hormone (PTH) response. Lithium as an essential monovalent cation has some structural similarity to calcium (Ca) and can interact with protein receptors. This leads to changes in the inhibitory configuration of PTH and increased serum calcium concentrations, rising the threshold necessary to suppress hormone secretion.Lithium-induced hyperparathyroidism (HIL) is the main cause of hypercalcemia in these patients.ObjectivesBased on a clinical case of lithium-associated hypercalcemia in a patient with bipolar disorder, review the existing literature and state the needs for periodic monitoring protocols.MethodsCase report and bibliographical review.ResultsA 38-year-old woman, diagnosed with bipolar affective disorder at the age of 18, has been treated with lithium during which she developed secondary tubulointerstitial nephropathy as an adverse effect. Recently, she requested medical evaluation for constitutional syndrome associated with deterioration of general condition with loss of strength and difficulty in walking. Analytically, mild hypercalcemia was detected, and the study was extended to include Ca and PTH.Chronic lithium therapy often develops mild hypercalcemia (approximately 10 to 20 percent of patients taking lithium), most likely due to increased secretion of PTH. Lithium can also unmask previously unrecognized mild hyperparathyroidism in patients with adenomas within a few years of starting therapy or induce parathyroid hyperplasia with a chronic use.The hypercalcemia usually, but not always, subsides when the lithium is stopped. Normalization of serum calcium is more likely to occur one to four weeks post-lithium withdrawal in patients with a relatively short duration of lithium use. It is less likely in patients receiving lithium for more than 10 years.Regarding the case to be presented, a review of the literature is carried out and the need to propose periodic calcium monitoring protocols is exposed.ConclusionsRecommendations include determination of serum calcium every 6 months, urinary calcium and creatinine every 12 months, and bone mineral density monitoring every 1 to 3 years. Regular analytical monitoring including total calcium, PTH and vitamin D, would identify patients with a tendency to hypercalcemia so that appropriate measures could be taken. So as chronic treatment with lithium can develop mild hypercalcemia, I consider it necessary to develop periodic monitoring protocols for this adverse effect.Disclosure of InterestNone Declared