TRPC3 Is Downregulated in Primary Hyperparathyroidism.

Transient receptor potential canonical sub-family channel 3 (TRPC3) is considered to play a critical role in calcium homeostasis. However, there are no established findings in this respect with regard to TRPC6. Although the parathyroid gland is a crucial organ in calcium household regulation, little is known about the protein distribution of TRPC channels-especially TRPC3 and TRPC6-in this organ. Our aim was therefore to investigate the protein expression profile of TRPC3 and TRPC6 in healthy and diseased human parathyroid glands. Surgery samples from patients with healthy parathyroid glands and from patients suffering from primary hyperparathyroidism (pHPT) were investigated by immunohistochemistry using knockout-validated antibodies against TRPC3 and TRPC6. A software-based analysis similar to an H-score was performed. For the first time, to our knowledge, TRPC3 and TRPC6 protein expression is described here in the parathyroid glands. It is found in both chief and oxyphilic cells. Furthermore, the TRPC3 staining score in diseased tissue (pHPT) was statistically significantly lower than that in healthy tissue. In conclusion, TRPC3 and TRPC6 proteins are expressed in the human parathyroid gland. Furthermore, there is strong evidence indicating that TRPC3 plays a role in pHPT and subsequently in parathyroid hormone secretion regulation. These findings ultimately require further research in order to not only confirm our results but also to further investigate the relevance of these channels and, in particular, that of TRPC3 in the aforementioned physiological functions and pathophysiological conditions.

Thoracoscopic treatment of mediastinal ectopic parathyroid adenomas: a Latinamerica experience case series and literature review.

BACKGROUND: Hyperparathyroidism (HPT) is a disease caused by hypersecretion of one or more parathyroid glands, it can be associated with ectopic mediastinal parathyroid glands (MEPA) in 2% of cases. The use of video-assisted thoracoscopic surgery (VATS) for the surgical resection of these glands is a safe, cost-effective, and low morbidity option for patients with MEPA. We report a case series of patients with this disease managed with VATS, the first in Mexico and Latinamerica. METHODS: From 2008 to 2022, a retrospective study involving patients with MEPA and treated by VATS approach was performed in a tertiary hospital in Mexico city. Relevant biochemical and clinical variables such as imaging studies, pre and postoperative laboratory results, surgical strategy, outcomes and pathological analysis were analyzed. RESULTS: Four cases of mediastinal parathyroid adenomas causing HPT were included. All patients were female with a median age of 52.5 years-old (range 46-59 years), half of the patients had primary HPT and the others tertiary HPT after kidney transplant. 75% of cases had a MEPA in the medium mediastinum, all had a preoperative positive SPECT-CT 99mTc Sestamibi scan. Mean preoperative PTH was 621.3pg/mL (182-1382pg/mL). All patients successfully underwent parathyroidectomy with a VATS approach, no deaths were reported. CONCLUSIONS: VATS is a minimally invasive surgery that provides adequate access to mediastinal located glands, optimal visualization of mediastinal structures and has a high resection success rate with less complications and morbidity than open approaches.

Atypical parathyroid adenoma with severe bone manifestations in early adolescence.

This is a case of primary hyperparathyroidism in a female teenager with multiple fractures and severe bone manifestations. The histopathology revealed atypical parathyroid adenoma, an exceedingly rare form of hyperparathyroidism; its main differential diagnosis is parathyroid carcinoma, as it shares both clinical and histological characteristics with it, in addition to its still uncertain malignant potential.

Transplantation and Noninvasive Longitudinal In Vivo Imaging of Parathyroid Cells: A Proof-of-Concept Study.

The parathyroid cell is a vital regulator of extracellular calcium levels, operating through the secretion of parathyroid hormone (PTH). Despite its importance, the regulation of PTH secretion remains complex and not fully understood, representing a unique interplay between extracellular and intracellular calcium, and hormone secretion. One significant challenge in parathyroid research has been the difficulty in maintaining cells ex vivo for in-depth cellular investigations. To address this issue, we introduce a novel platform for parathyroid cell transplantation and noninvasive in vivo imaging using the anterior chamber of the eye as a transplantation site. We found that parathyroid adenoma tissue transplanted into the mouse eye engrafted onto the iris, became vascularized, and retained cellular composition. Transplanted animals exhibited elevated PTH levels, indicating a functional graft. With in vivo confocal microscopy, we were able to repetitively monitor parathyroid graft morphology and vascularization. In summary, there is a pressing need for new methods to study complex cellular processes in parathyroid cells. Our study provides a novel approach for noninvasive in vivo investigations that can be applied to understand parathyroid physiology and pathology under physiological and pathological conditions. This innovative strategy can deepen our knowledge on parathyroid function and disease.

High lymphocyte signature genes expression in parathyroid endocrine cells and its downregulation linked to tumorigenesis.

BACKGROUND: To date, because of the difficulty in obtaining normal parathyroid gland samples in human or in animal models, our understanding of this last-discovered organ remains limited. METHODS: In the present study, we performed a single-cell transcriptome analysis of six normal parathyroid and eight parathyroid adenoma samples using 10 × Genomics platform. FINDINGS: We have provided a detailed expression atlas of parathyroid endocrine cells. Interestingly, we found an exceptional high expression levels of CD4 and CD226 in parathyroid endocrine cells, which were even higher than those in lymphocytes. This unusual expression of lymphocyte markers in parathyroid endocrine cells was associated with the depletion of CD4 T cells in normal parathyroid glands. Moreover, CD4 and CD226 expression in endocrine cells was significantly decreased in parathyroid adenomas, which was associated with a significant increase in Treg counts. Finally, along the developmental trajectory, we discovered the loss of POMC, ART5, and CES1 expression as the earliest signature of parathyroid hyperplasia. INTERPRETATION: We propose that the loss of CD4 and CD226 expression in parathyroid endocrine cells, coupled with an elevated number of Treg cells, could be linked to the pathogenesis of parathyroid adenoma. Our data also offer valuable information for understanding the noncanonical function of CD4 molecule. FUNDING: This work was supported by the National Key R&D Program of China (2022YFA0806100), National Natural Science Foundation of China (82130025, 82270922, 31970636, 32211530422), Shandong Provincial Natural Science Foundation of China (ZR2020ZD14), Innovation Team of Jinan (2021GXRC048) and the Outstanding University Driven by Talents Program and Academic Promotion Program of Shandong First Medical University (2019LJ007).

Imaging Characteristics and Interpretation Strategy for Renal Hyperparathyroidism: A Retrospective 4-Dimensional Computed Tomography Study.

OBJECTIVE: Parathyroidectomy treats uncontrolled renal hyperparathyroidism (RHPT), requiring identification of all glands. Three types of enhancement are proposed. Type A lesions have higher arterial phase attenuation than the thyroid, type B lesions lack higher arterial phase attenuation but have lower venous phase attenuation, and type C lesions have neither higher arterial phase attenuation nor lower venous phase attenuation than the thyroid. We aimed to outline the image features of problematic parathyroid glands in RHPT and propose a 4-dimensional computed tomography (4DCT) interpretation algorithm. METHODS: This retrospective study involved data collection from patients with RHPT who underwent preoperative 4DCT for parathyroidectomy between January and November 2022. Pathologically confirmed parathyroid lesions were retrospectively identified on 4DCT according to the location and size described in the surgical notes. The attenuation of parathyroid lesions and the thyroid glands was assessed in 3 phases, and demographic data of the patients were collected. RESULTS: Ninety-seven pathology-proven parathyroid glands from 27 patients were obtained, with 86 retrospectively detected on 4DCT. In the arterial phase, the attenuation of parathyroid lesions in RHPT did not exceed that of the thyroid gland (P < .001). In the venous phase, parathyroid lesions demonstrated lower attenuation than the thyroid gland (P < .001). A total of 81 parathyroid lesions (94.2%) exhibited type B patterns. CONCLUSION: Unlike primary hyperparathyroidism, lesions in RHPT exhibited more type B enhancement, making them less readily identifiable in the arterial phase. Therefore, we propose a distinct imaging interpretation strategy to locate these problematic glands more efficiently.

[Effect of dual fluorescence imaging in identifying central lymph nodes and parathyroid glands during thyroid cancer surgery].

Objective: To investigate the effect of dual fluorescence imaging in identifying central lymph nodes and parathyroid glands during thyroid cancer surgery. Methods: This study was a cross-sectional study. Patients who underwent surgery for papillary thyroid cancer (PTC) at the Department of Head and Neck Surgery, Beijing Tongren Hospital, Capital Medical University between January 2022 and September 2023 were included. All patients underwent thyroid lobectomy or total resection, and central lymph node dissection was performed at the same time. During the operation, tracing injection of mitoxantrone hydrochloride and 785 nm and 660 nm dual fluorescence imaging technique were used to measure the fluorescence intensity (FI) of parathyroid glands, central lymph nodes and background. After correcting to obtain the standardized FI, the paired t-test was used to compare the standardized FI of the parathyroid glands and central lymph nodes, and the Spearman's rank correlation analysis was used to analyze the relationship between the standardized FI and various clinical indicators. Results: The study included 30 patients (8 males and 22 females), with a mean age of (41.8±10.4) years. A total of 76 parathyroid glands and 234 central lymph nodes were identified under dual fluorescence imaging, and the standardized FI of parathyroid glands was less than that of central lymph nodes (44.7±16.8 vs 99.5±28.4, P<0.001). The visualization rate, false rate and miscut rate of parathyroid glands under 785 nm wavelength excitation light were 98.7% (76/77), 0 (0/77) and 1.3% (1/77), respectively (one case with no visualization and miscutting parathyroid gland was the encapsulated type). The visualization rate of central lymph nodes under 660 nm wavelength excitation light was 98.7% (234/237). There was no significant correlation between FI and clinical indicators such as gender, age, height, weight, body mass index, preoperative thyroid stimulating hormone, thyroglobulin antibody, thyroid microsomal antibody, serum calcium, parathyroid hormone level and surgical procedure (all P>0.05). Conclusion: Dual fluorescence imaging of central lymph nodes and parathyroid glands can improve the ability to identify parathyroid gland while assisting central lymph node dissection.

Diagnostic Performance of 99mTc-Sestamibi SPECT/CT and 18F-Choline PET/CT in Locating Hyperfunctioning Parathyroid Glands in Patients with Primary Hyperparathyroidism.

OBJECTIVE: This study aimed to assess the diagnostic performance of 99mTc-sestamibi SPECT/CT and 18F-choline PET/CT in detecting hyperfunctioning parathyroid glands in patients undergoing surgery for primary hyperparathyroidism (PHPT). METHODS: A retrospective analysis was conducted on patients who underwent PHPT-related surgery between April 2019 and May 2022. The study focused on patients undergoing either 99mTc-sestamibi SPECT/CT (81 patients) or 18F-choline PET/CT (33 patients) scans before surgery to pinpoint hyperfunctioning parathyroid gland(s). In the majority of patients, 18F-choline PET/CT was performed after negative or inconclusive findings on 99mTc-sestamibi SPECT/CT. Pathohistological reports were utilized as the reference standard for evaluating the accuracy of the imaging findings. RESULTS: The study encompassed 83 patients (70 females, 84.3%) with an average age of 57.2 years (24-80 years). The pathohistological analysis identified a total of 98 glands. In a per-lesion analysis, the detection rate of 99mTc-sestamibi SPECT/CT was 57% (95% CI 45.3-68.1), while the detection rate of 18F-choline PET/CT was 90.3% (95% CI 74.3-98.0). CONCLUSION: The results of our study showed the significant usefulness of 18F-choline PET/CT in patients with negative or inconclusive results of 99mTc-sestamibi SPECT/CT in accurately locating hyperfunctioning parathyroid glands in PHPT patients.

Fine needle aspiration biopsy of parathyroid; is it meaningful? A cytologic study of 81 cases with histological and clinical correlations.

BACKGROUND: Recognizing the parathyroid gland and distinguishing the parathyroid from thyroid lesions in fine needle aspiration (FNA) is challenging. This study aimed to identify cytomorphologic features suggestive of parathyroid origin and to assess the utility of cytopathology in conjunction with ancillary tests in the identification of parathyroid glands. MATERIALS AND METHODS: Ultrasound (US) guided FNA of parathyroid gland and lesions in 81 patients were reviewed concerning clinical history and correlated to histopathologic findings in available cases. FNA smears were evaluated for cellularity, architectural patterns, cellular and nuclear features, and background of the smears. In 78 cases, FNA was supplemented by a measurement of parathormone (PTH) levels in the needle washout fluid (FNA-PTH assay) and/or GATA3/PTH/chromogranin-A immunostainings. RESULTS: Sixty-four cases were diagnosed cytologically as parathyroid lesions in conjunction with FNA-PTH assay and/or immunocytochemical examinations. In an additional nine cases, a diagnosis of parathyroid lesions was rendered after repeated FNA with FNA-PTH assay. The histolopathologic diagnosis of surgically excised cases (n = 75) included parathyroid adenoma (60 cases), atypical parathyroid adenoma (4 cases), parathyroid hyperplasia (10 cases), and parathyroid carcinoma (1 case). Major cytological findings of parathyroid tissue included high cellularity, scattered naked nuclei, cribriform and three-dimensional clusters, stippled chromatin, and oxyphilic cytoplasm while papillary pattern or colloid-like material was identified in three cases respectively. No nuclear grooves or inclusions were seen in any case. CONCLUSIONS: High cellularity scattered naked nuclei, cribriform and three-dimensional patterns, stippled chromatin and oxyphilic cytoplasm are cytomorphologic features that favour parathyroid origin. A combination of these features with FNA-PTH assay and/or GATA3, PTH, and chromogranin-A immunostainings on cytologic specimens aid in the identification of parathyroid glands and the distinguishing of parathyroid from thyroid lesions.

How often are intrathyroidal parathyroid glands a cause of primary hyperparathyroidism, and how should they be managed?

BACKGROUND: The purpose of our study was to determine the frequency and management of intrathyroidal parathyroid glands in patients with primary hyperparathyroidism and evaluate whether intrathyroidal parathyroid glands were more often superior or inferior glands. METHODS: A retrospective review of the prospective parathyroid database was completed to determine the number of patients with primary hyperparathyroidism and an intrathyroidal parathyroid gland. Demographic data, laboratory and localization studies, operative management, pathology, and outcome were determined for patients with an intrathyroidal parathyroid gland and were compared with patients with an extrathyroidal parathyroid gland. RESULTS: From 1990-2023, 808 patients were operated on for primary hyperparathyroidism; 17 (2%) patients had an intrathyroidal parathyroid gland, an adenoma in 15 (88.2%), and a hyperplastic gland in 2 (11.8%). The mean age was 53 years; 16 (94%) patients were female. Mean calcium and parathyroid hormone was 12 mg/dL and 150 pg/mL, and there were no differences from the extrathyroidal parathyroid group. Ultrasound and Sestamibi imaging were valuable in identifying an intrathyroidal parathyroid gland in 10 of 13 patients and 13 of 17 patients, respectively. Local excision was performed in 9 (53%) patients and lobectomy in 8 (47%) patients. Intraoperative parathyroid hormone was measured and predictive of cure in 12 patients. The location of intrathyroidal parathyroid glands was determined in 15 patients and was inferior in 11 (73%). All patients were cured. No patient developed recurrent disease after a median 54-month follow-up. CONCLUSION: Intrathyroidal parathyroid glands are the cause of primary hyperparathyroidism in 2% of patients and are most often inferior glands. Local excision was accomplished in 53% of our patients.

Comparison of incidental parathyroid tissue detection rates on pathology after total thyroidectomy performed with or without near-infrared autofluorescence imaging.

BACKGROUND: Near-infrared autofluorescence imaging is an adjunct to parathyroid identification. As it does not show perfusion, it is important to study its impact during thyroidectomy by measuring quantifiable data on parathyroid detection rather than function. The aim of this study was to compare incidental parathyroidectomy rates in patients undergoing total thyroidectomy with or without near-infrared autofluorescence. METHODS: Retrospective study of patients who underwent total thyroidectomy between 2014 and 2022 at one center. Clinical parameters, including rates of incidental parathyroid tissue on pathology reports, were compared between near-infrared autofluorescence and non-near-infrared autofluorescence groups. Near-infrared autofluorescence was used to guide dissection (identification) and/or to confirm tissue as parathyroid (confirmation). Statistical analysis was done with Wilcoxon rank sum test and χ2 analysis. RESULTS: There were 300 patients in the near-infrared autofluorescence and 750 patients in the non-near-infrared autofluorescence group. The rate of incidental parathyroid tissue detection on final pathology was 13.3% (n = 40) in the near-infrared autofluorescence and 23.2% (n = 174) in the non-near-infrared autofluorescence group (P < .001). The rate of incidental parathyroid tissue detected on pathology with near-infrared autofluorescence decreased when used for identification and confirmation of parathyroid tissue (30.0% to 13.4%, P < .001), but not when used for confirmation only (19.6% to 18.5%, P = .89). Impact of near-infra red autofluorescence in decreasing the rate of incidental parathyroid tissue was more profound for early (38.5% to 17.1%) versus mid-late career surgeons (20% to 13%). CONCLUSION: Our results suggest that the use of near-infrared autofluorescence may help decrease the rate of incidental parathyroid tissue detected on final pathology if used for both identification and confirmation of parathyroid glands during thyroidectomy.

Molecular Genetic Aspects of Sporadic Multiglandular Primary Hyperparathyroidism.

Multiglandular primary hyperparathyroidism (MGD) represents a rare form of primary hyperparathyroidism (PHPT). MGD is associated with hereditary PHPT, but the sporadic MGD is more common and affects a similar patient profile as single gland parathyroid disease (SGD). The distinction between SGD and MGD is of great clinical importance, especially for the strategy of parathyroidectomy. Based on the limited knowledge available, MGD is likely to be a genetically heterogeneous disease resulting from the interaction of germline and somatic DNA mutations together with epigenetic alterations. Furthermore, these events may combine and occur independently in parathyroid tumors within the same individual with MGD. Gene expression profiling has shown that SGD and MGD may represent distinct entities in parathyroid tumorigenesis. We are waiting for studies to analyze exactly which genes are different in SGD and MGD in order to identify potential biomarkers that can distinguish between the two forms of the disease.

Ultrasound-guided microwave ablation in the treatment of recurrent primary hyperparathyroidism in a patient with MEN1: a case report.

Background: Multiple endocrine neoplasia type 1 (MEN1) is an inherited endocrine syndrome caused by the mutation in the tumor suppressor gene MEN1. The recurrence rate of primary hyperparathyroidism (PHPT) in patients with MEN1 after parathyroidectomy remains high, and the management of recurrent hyperparathyroidism is still challenging. Case presentation: We reported a 44-year-old woman with MEN1 combined with PHPT who was diagnosed through genetic screening of the patient and her family members. After parathyroidectomy to remove one parathyroid gland, the patient suffered from persistent high levels of serum calcium and parathyroid hormone, which returned to normal at up to 8 months after ultrasound-guided microwave ablation (MWA) for bilateral parathyroid glands, suggesting an acceptable short-term prognosis. Conclusion: Ultrasound-guided MWA for parathyroid nodules may be an effective therapeutic strategy for recurrent PHPT in MEN1 patients.

Recurrence hyperparathyroidism caused by synchronous parathyroid carcinoma and parathyromatosis in a patient with long-term hemodialysis.

BACKGROUND: Parathyroid carcinoma and parathyromatosis are very rare diseases in patients on hemodialysis. Its pathogenesis, clinical features, preoperative diagnosis, and surgery are challenging. We describe a rare case of recurrent hyperparathyroidism due to synchronous parathyroid carcinoma and parathyromatosis. CASE PRESENTATION: A 46-year-old Chinese woman was diagnosed with end-stage renal disease and received regular hemodialysis. Four years later, she experienced discomfort due to itching and was diagnosed with drug-resistant secondary hyperparathyroidism. Parathyroidectomy was performed, and her parathyroid hormone (PTH) levels were reduced. The pathology also revealed that the four nodules were parathyroid nodular hyperplasia without evidence of malignancy. Five years after surgery, the right subcutaneous nodule and left inferior nodule were detected by multiple imaging modalities, and the nodules were accompanied by recurrence itching and elevation of PHT. A complete resection of two nodules was performed, and the patient was diagnosed with parathyroid carcinoma and parathyromatosis. At 8 months postsurgery, her PHT and serum calcium levels were stable, and there were no signs of recurrence. CONCLUSIONS: This is a rare case of synchronous parathyroid carcinoma and parathyromatosis in a patient with secondary hyperparathyroidism after parathyroidectomy. We suggest meticulous handling of parathyroid hyperplasia to avoid rupture and spillage during surgery, and precise pro-operation location by multiple imaging modalities is crucial for successful parathyroidectomy.

The Induction of Parathyroid Cell Differentiation from Human Induced Pluripotent Stem Cells Promoted Via TGF-α/EGFR Signaling.

The parathyroid gland plays an essential role in mineral and bone metabolism. Cultivation of physiological human parathyroid cells has yet to be established and the method by which parathyroid cells differentiate from pluripotent stem cells remains uncertain. Therefore, it has been hard to clarify the mechanisms underlying the onset of parathyroid disorders, such as hyperparathyroidism. In this study, we developed a new method of parathyroid cell differentiation from human induced pluripotent stem (iPS) cells. Parathyroid cell differentiation occurred in accordance with embryologic development. Differentiated cells, which expressed the parathyroid hormone, adopted unique cell aggregation similar to the parathyroid gland. In addition, these differentiated cells were identified as calcium-sensing receptor (CaSR)/epithelial cell adhesion molecule (EpCAM) double-positive cells. Interestingly, stimulation with transforming growth factor-α (TGF-α), which is considered a causative molecule of parathyroid hyperplasia, increased the CaSR/EpCAM double-positive cells, but this effect was suppressed by erlotinib, which is an epidermal growth factor receptor (EGFR) inhibitor. These results suggest that TGF-α/EGFR signaling promotes parathyroid cell differentiation from iPS cells in a similar manner to parathyroid hyperplasia.

Spontaneous resolution of primary hyperparathyroidism post-biopsy-related neck haematoma.

Spontaneous or fine-needle aspiration (FNA)-induced remission of primary hyperparathyroidism (PHPT) is an extremely rare phenomenon with variable outcomes. We report a 75-year-old Male who initially presented with left ureteric calculi and was found to have PHPT. Imaging studies including ultrasound neck, parathyroid sestamibi scan and computed tomography of thorax, abdomen, and pelvis failed to identify the culprit lesion and exploratory parathyroidectomy was planned. Before surgery, he underwent FNA for cytology of a right cold thyroid nodule which was complicated with a large neck haematoma and dysphagia. The cytology of the aspirated fluid was consistent with a benign cyst. One month after the procedure, serum calcium and phosphate normalised along with resolution of haematoma. He remained in biochemical remission at 1-year follow-up with the latest ultrasound of neck showing resolution of a large colloid nodule that was previously seen occupying the right thyroid lobe.

Incremental value of 99m Tc-MIBI single-photon emission computed tomography/computed tomography fusion imaging for the diagnosis of secondary hyperparathyroidism.

PURPOSE: To assess the added value of 99m Tc-MIBI single-photon emission computed tomography/computed tomography (SPECT/CT) fusion imaging over dual-phase scintigraphy in the diagnosis of secondary hyperparathyroidism (SHPT). METHODS: This retrospective study included 23 patients with SHPT. The diagnostic efficacy of 99m Tc-MIBI dual-phase scintigraphy and SPECT/CT fusion imaging was analyzed and compared based on the result of postoperative pathology and follow-up. To evaluate the diagnostic ability of 99m Tc-MIBI dual-phase scintigraphy, the volume and radioactive count of parathyroid lesions were assessed using the region of interest method. RESULTS: A total of 79 hyperplastic parathyroid glands and two thyroid tissues were surgically removed from 23 SHPT patients and 13 normal parathyroid glands were preserved. 99m Tc-MIBI SPECT/CT fusion imaging showed higher sensitivity and accuracy than 99m Tc-MIBI dual-phase scintigraphy [sensitivity, 77.2% (61/79) vs 46.8% (37/79); accuracy, 80.4% (74/92) vs 54.3% (50/92), respectively], but comparable specificity [100% (13/13)). Among 61 positive lesions detected by 99m Tc-MIBI SPECT/CT fusion imaging, 37 were dual-phase scintigraphy positive and 24 were dual-phase scintigraphy false negative. The radioactivity counts and radioactivity per unit volume in dual-phase scintigraphy positive were higher than that in dual-phase scintigraphy false negative ( P  < 0.05), but the volume of parathyroid lesions between the two groups had no significant difference ( P  > 0.05). CONCLUSION: Compared with 99m Tc-MIBI dual-phase scintigraphy, 99m Tc-MIBI SPECT/CT fusion imaging has incremental value in the diagnosis of SHPT. The low uptake of MIBI in the whole gland and low MIBI uptake per unit volume are easy to cause dual-phase scintigraphy false negative.

Identification of key biomarkers based on the proliferation of secondary hyperparathyroidism by bioinformatics analysis and machine learning.

Objective: Secondary hyperparathyroidism (SHPT) is a frequent complication of chronic kidney disease (CKD) associated with morbidity and mortality. This study aims to identify potential biomarkers that may be used to predict the progression of SHPT and to elucidate the molecular mechanisms of SHPT pathogenesis at the transcriptome level. Methods: We analyzed differentially expressed genes (DEGs) between diffuse and nodular parathyroid hyperplasia of SHPT patients from the GSE75886 dataset, and then verified DEG levels with the GSE83421 data file of primary hyperparathyroidism (PHPT) patients. Candidate gene sets were selected by machine learning screens of differential genes and immune cell infiltration was explored with the CIBERSORT algorithm. RcisTarget was used to predict transcription factors, and Cytoscape was used to construct a lncRNA-miRNA-mRNA network to identify possible molecular mechanisms. Immunohistochemistry (IHC) staining and quantitative real-time polymerase chain reaction (qRT-PCR) were used to verify the expression of screened genes in parathyroid tissues of SHPT patients and animal models. Results: A total of 614 DEGs in GSE75886 were obtained as candidate gene sets for further analysis. Five key genes (USP12, CIDEA, PCOLCE2, CAPZA1, and ACCN2) had significant expression differences between groups and were screened with the best ranking in the machine learning process. These genes were shown to be closely related to immune cell infiltration levels and play important roles in the immune microenvironment. Transcription factor ZBTB6 was identified as the master regulator, alongside multiple other transcription factors. Combined with qPCR and IHC assay of hyperplastic parathyroid tissues from SHPT patients and rats confirm differential expression of USP12, CIDEA, PCOLCE2, CAPZA1, and ACCN2, suggesting that they may play important roles in the proliferation and progression of SHPT. Conclusion: USP12, CIDEA, PCOLCE2, CAPZA1, and ACCN2 have great potential both as biomarkers and as therapeutic targets in the proliferation of SHPT. These findings suggest novel potential targets and future directions for SHPT research.