Capsiate ameliorates secondary hyperparathyroidism by improving insulin sensitivity and inhibiting angiogenesis.

Secondary hyperparathyroidism has a significant impact on the overall well-being of the body. Capsiates, known for their antioxidant and metabolic properties, have emerged as a promising alternative treatment for secondary hyperparathyroidism. This study aims to evaluate the effects and mechanisms of capsiates in the treatment of secondary hyperparathyroidism. To achieve our research objectives, we conducted a study on patients' serum and examined changes in metabolic markers using serum metabolomics. We induced secondary hyperparathyroidism in rat through dietary intervention and divided them into four groups. The first group, referred to as the Parathyroid Hormone (PTH) group, received a low-calcium and high-phosphate diet (0.2% calcium, 1.2% phosphorus). The second group served as the control group, receiving a standard phosphate and calcium diet (0.6% calcium, 0.6% phosphorus). The third group, called the capsiates group, consisted of rat from the control group treated with capsiates (intraperitoneal injection of 2 mg/kg capsiates for 2 weeks after 2 weeks of dietary intervention). The fourth group was the capsiates-treated PTH group. Subsequently, we conducted ribose nucleic acid (RNA) sequencing on parathyroid gland cells and evaluated serum thyroxine levels, oxidative stress, expression of proteins associated with vascular neogenesis, measurement of SOD, GSH and 3-nitrotyrosine, micro-CT and histological staining. The serum metabolomic data revealed a significant decrease in capsiate levels in the secondary hyperparathyroidism group. Administration of capsiates to PTH rat resulted in increased calcium levels compared to the PTH group. Additionally, the PTH + Capsiates group showed significantly lower levels of PTH and phosphate compared to the PTH group. The PTH group exhibited a notable increase in the quantity and size of mitochondria compared to the control group. Following capsiates administration to the PTH group, there was a significant reduction in the number of mitochondria and length of microvilli, but an increase in the size of mitochondria compared to the PTH group. Sequencing analysis revealed that vascular endothelial growth factor (VEGF) and Vascular Endothelial Growth Factor Receptor 1 (VEGFR1) play crucial roles in this process. Vascular-related variables and downstream signalling were significantly elevated in hyperthyroidism and were alleviated with capsaicin treatment. Finally, combining capsiates with the PTH group improved bone mineral density, Tb.N, BV.TV, Cs.Th, Tt.Ar, OPG, Ob.TV and Oc.TV, as well as the mineral apposition rate, but significantly decreased Tb.Sp and Receptor Activator for Nuclear Factor-κ B Ligand (RANKL) compared to the PTH group. The findings suggest that capsiates can improve secondary hyperparathyroidism and ameliorated osteoporosis outcomes by inhibiting angiogenesis and reducing oxidative stress.

Analysis of neutrophil-to-lymphocyte and platelet-to-lymphocyte ratios as inflammatory biomarkers in chronic kidney disease: impact of parathyroidectomy.

INTRODUCTION: Secondary hyperparathyroidism (SHPT) is one of the causes for inflammation in CKD. We assessed the impact of parathyroidectomy (PTX) on neutrophil-to-lymphocyte (N/L) and platelet-to-lymphocyte (P/L) ratios in SHPT patients. METHODS: A total of 118 patients [hemodialysis (HD, n = 81), and transplant recipients (TX, n = 37)] undergoing PTX between 2015 and 2021 were analyzed. RESULTS: There was a significant reduction in calcium and PTH levels in both groups, in addition to an increase in vitamin D. In the HD group, PTX did not alter N/L and P/L ratios. In the TX group, there was a reduction in N/L and P/L ratios followed by a significant increase in total lymphocyte count. CONCLUSION: N/L and P/L ratios are not reliable biomarkers of inflammation in SHPT patients undergoing PTX. Uremia, which induces a state of chronic inflammation in dialysis patients, and the use of immunosuppression in kidney transplant recipients are some of the confounding factors that prevent the use of this tool in clinical practice.

Association of Coronary Calcium Score on Cardiac PET During Pre-Kidney Transplant Assessment with Persistent Hyperparathyroidism: A Retrospective Study.

BACKGROUND Secondary hyperparathyroidism and coronary calcifications are common complications in chronic kidney disease. However, the relation between coronary calcium score (CCS) and persistent hyperparathyroidism (pHPT) after kidney transplantation (KT) remains unknown. MATERIAL AND METHODS This was a single-center retrospective study of KT candidates from January 2017 to May 2020. We collected patients' demographics, cardiovascular (CV) risk factors, and the findings of pre-KT CV imaging. We also collected parathyroid hormone (PTH) values before KT, at 1-6 months, 6-12 months, and 12-24 months after KT. We defined pHPT as PTH ≥25.5 pmol/L after 12 months post-KT. RESULTS A total of 111 KT recipients (KTRs) with a mean age of 50.4 years were included, of which 62.2% were men and 77.5% were living-donor KTRs. Dialysis modality used before KT was peritoneal dialysis in 9.9% and hemodialysis in 82.9%. Dialysis vintage was 3±2.9 years. The prevalence of pHPT was 24.3% (n=27), and the prevalence of severe coronary calcifications (CCS >400 Agatston units) was 19.8% (n=22). PTH values at baseline, 1-6 months, 6-12 months, and 12-24 months were not different among between CCS >400 or CCS <400 groups. However, pHPT after KT was significantly more prevalent in KTRs with severe CCS (37% vs 14.3%, p=0.014). Severe CCS was associated with less improvement of PTH values after KT (r=0.288, p=0.020). Otherwise, the findings of cardiac PET and coronary angiogram were not significantly different between pHPT and non-pHPT patients. CCS >400 was independently associated with pHPT after transplant (aOR=18.8, P=0.012). CONCLUSIONS Severe CCS on pre-KT cardiac assessment is associated with pHPT after KT.

Outcome of surgical parathyroidectomy for tertiary hyperparathyroidism in kidney transplant recipients: tertiary hyperparathyroidism should not be ignored, for the sake of precious allografts.

Tertiary hyperparathyroidism is a complication of kidney transplantation. This complicated condition carries over from the dialysis period and varies according to the function of the transplanted allograft. Treatments include pharmacotherapy (mainly using calcimimetics) and parathyroidectomy, but calcimimetics are currently not covered by the national insurance system in Japan. Two types of parathyroidectomy can be performed: subtotal parathyroidectomy; and total parathyroidectomy with partial autograft. Both types can be expected to improve hypercalcemia. Concerns about the postoperative deterioration of allograft function are influenced by preoperative allograft function, which is even more likely to be affected by early surgery after kidney transplantation. In general, transient deterioration of allograft function after surgery is not expected to affect graft survival rate in the medium to long term. Tertiary hyperparathyroidism in kidney transplant recipients negatively impacts allograft and patient survival rates, and parathyroidectomy can be expected to improve prognosis in both kidney recipients and dialysis patients. However, studies offering high levels of evidence remain lacking.

Moderate salt restriction in primary aldosteronism improves bone metabolism through attenuation of urinary calcium and phosphate losses.

Accumulating evidence links osteoporosis and dietary salt consumption. Primary aldosteronism (PA) is a model disease with increased dietary salt intake and constitutes an independent risk factor for osteoporosis. We, thus, assessed whether a short-term moderate reduction in salt intake in PA results in detectable osteoanabolic effects. Forty-one patients with PA on stable mineralocorticoid receptor antagonist therapy were subjected to a 12-week salt restriction. Serum and urinary electrolytes, markers of bone turnover, and a 15 steroids plasma profile were registered. After 12 weeks, urinary calcium and phosphate decreased, while plasma testosterone, serum phosphate, and bone alkaline phosphatase (BAP) all increased significantly. Longitudinal changes in BAP were independently correlated with changes in serum phosphate, parathyroid hormone, and urinary calcium in multivariate analysis. Salt restriction in PA limits urinary calcium and phosphate losses and may confer favorable osteoanabolic effects. Our findings suggest that salt restriction should be considered in patients with PA to improve bone health.

Parathyroid fine needle aspiration with PTH washout: Can it lead to parathyroid cell seeding in primary hyperparathyroidism?

Although parathyroid fine-needle aspiration (P-FNA) with parathyroid hormone (PTH) washout is effective in detecting preoperative parathyroid lesions, it also presents risks such as fibrosis, hematoma, and, in rare cases, tumor seeding. This study aimed to investigate whether P-FNA with PTH washout leads to the seeding of parathyroid cells along the path of the needle. A retrospective analysis was conducted on patients undergoing minimally invasive parathyroidectomy guided by preoperative PTH washout. Permanent pathology reports, imaging data, and postoperative serum parathyroid hormone and calcium levels were assessed to determine the effectiveness and safety of the procedure. Complications following P-FNA with PTH washout were also reviewed using data from the patient registration system of Bulent Ecevit University. The procedure accurately localized parathyroid adenomas in 87 patients who underwent ultrasound-guided parathyroidectomy following preoperative P-FNA and PTH washout. Postoperatively, 75 patients showed normal parathyroid hormone and calcium levels. Two patients required secondary surgery for contralateral adenomas. Critically, there was no evidence of P-FNA with PTH washout-induced parathyromatosis or seeding during the follow-up. Effective adenoma localization is crucial for successful minimally invasive surgery of hyperparathyroidism. Our study indicates that combining preoperative P-FNAB with PTH washout and imaging enhances adenoma detection, especially when intraoperative PTH measurements are not available, thus improving surgical outcomes. Notably, we found no evidence of cell implantation after P-FNA, suggesting the safety and efficacy of this method for preventing parathyroid cell seeding.

Vitamin D metabolism in critically ill patients with acute kidney injury: a prospective observational study.

BACKGROUND: Vitamin D deficiency in critically ill patients is associated with poor outcomes, and vitamin D supplementation is recommended for patients with chronic kidney disease. Whether acute kidney injury (AKI) is associated with altered Vitamin D metabolism is unknown. We aimed to compare the longitudinal profiles of serum 25(OH)D and 1,25(OH)2D concentrations in critically ill patients with and without moderate to severe AKI and explore the impact of renal recovery and parathyroid hormone (PTH). METHODS: In this prospective, observational study in two centres in the UK, critically ill patients with and without AKI underwent serial measurement of serum 25(OH)D and 1,25(OH)2D and plasma PTH concentrations for 5 days. Linear mixed model analysis and sensitivity analyses were performed. RESULTS: Serial data of 137 patients were analysed. Seventy-one patients had AKI stage II/III of whom 23 recovered kidney function during the 5-day study period; 66 patients did not have AKI at enrolment of whom 14 developed new AKI. On day of enrolment, patients' serum 25(OH)D concentrations were low (median 18 nmol/L) but there was no significant difference between patients with and without AKI. Median serum 1,25(OH)2D levels were significantly lower in patients with AKI II/III (41 pmol/L [IQR 26, 58]) compared to similarly unwell patients without AKI (54 pmol/L [IQR 33, 69]) during the 5-day period. Recovery of kidney function in patients with AKI was associated with a rise in 1,25(OH)2D concentrations. Plasma PTH results were impacted by serum calcium and magnesium levels but not associated with 1,25(OH)2D levels. CONCLUSIONS: Critically ill patients with moderate-to-severe AKI have significantly lower serum 1,25(OH)2D concentrations than similarly sick patients without AKI but there was no difference in serum 25(OH)D concentrations. Recovery of AKI was associated with a rise in serum 1,25(OH)2D concentrations. More research is needed to investigate the health benefits and safety of supplementation with active vitamin D in critically ill patients with moderate-to-severe AKI. Trial registration Clinicaltrials.gov (NCT02869919), registered on 16 May 2016.

Predictive analysis of severe hypocalcemia following total parathyroidectomy for renal secondary hyperparathyroidism.

OBJECTIVE: This study aimed to evaluate the incidence and identify risk factors for severe hypocalcemia following total parathyroidectomy (TPTX) in patients with renal secondary hyperparathyroidism (SHPT). PATIENTS AND METHODS: We included patients undergoing maintenance hemodialysis or peritoneal dialysis who underwent TPTX from January 1, 2018, to April 30, 2023. Participants were categorized into groups based on postoperative corrected serum calcium levels: severe hypocalcemia (<1.8 mmol/L) and non-severe hypocalcemia (≥1.8 mmol/L). We conducted univariate analyses of demographic and laboratory data to identify potential risk factors, which were further analyzed using a binary logistic regression model. RESULTS: Significant associations were observed with age, dialysis duration exceeding five years, type of dialysis (peritoneal dialysis), lower preoperative corrected serum calcium, elevated preoperative intact parathyroid hormone (iPTH), and increased preoperative alkaline phosphatase (ALP) levels (all p<0.05). Age, preoperative iPTH, and ALP levels were identified as independent risk factors for severe hypocalcemia post-TPTX. CONCLUSIONS: Younger patients with renal SHPT who have elevated preoperative iPTH and ALP levels are at an increased risk of experiencing severe hypocalcemia following TPTX. These findings underscore the importance of careful preoperative assessment and monitoring to mitigate the risk of this complication.

Fibroblast growth factor-23 and Alpha-Klotho concentrations in dogs with canine Leishmaniasis.

This study aimed to assess the concentrations of Fibroblast Growth Factor-23 (FGF-23) and α-Klotho in healthy dogs and dogs at different stages of Canine Leishmaniasis (CanL), and investigate the changes of these parameters in relation to renal function and calcium­phosphorus metabolism. A total of 74 dogs (22 healthy and 52 with CanL) of varying ages, sexes, and medium-sized breeds were included. Dogs with CanL were categorized into different stages (Stage I-IV) based on Leishvet recommendations. In addition to routine hematological parameters, plasma FGF-23, serum α-Klotho, urea, creatinine, phosphorus, calcium, parathormone, vitamin D concentrations, and urine protein/creatinine ratio were measured. Data from healthy dogs were compared to dogs with CanL overall and by stage. Dogs with CanL exhibited higher concentrations of FGF-23 (p < 0.05), α-Klotho, and parathormone (p < 0.001), as well as lower concentrations of vitamin D and calcium (p < 0.001). FGF-23 concentration was particularly elevated in Stage IV compared to other stages. However, no significant differences in α-Klotho levels were observed among the stages. FGF-23 levels showed a weak positive correlation with urea and creatinine concentrations and a moderate positive correlation with urine protein/creatinine ratio. This study demonstrated increased levels of FGF-23 and α-Klotho in dogs with CanL for the first time. The increase in FGF-23 levels was more prominent in advanced stages of the disease and correlated with higher urea and creatinine concentrations. These findings may serve as a basis for future diagnostic and therapeutic investigations, contributing to the understanding of the pathophysiology of kidney disease in CanL.

Determinants of hyperparathyroidism in children after kidney transplantation.

INTRODUCTION: Hyperparathyroidism (HPT) can contribute to metabolic bone disease following kidney transplantation. We evaluated post-transplant trends in intact parathyroid hormone (iPTH) and determined predictors of HPT in pediatric kidney transplant (KTx) recipients. METHODS: In this single-center study, retrospective data were collected on 88 children from 2013 to 2019. Data collected included dialysis vintage, biochemical parameters, post-transplant trends in iPTH, 25(OH)Vitamin D levels and estimated glomerular filtration rate (eGFR ml/min/1.73 m2 ). Pre-transplant treatment for HPT was quantified with a Treatment Burden score (TB, score range: 0-100). After log-transforming skewed variables (iPTH and eGFR), multivariable linear regression was performed to determine predictors of log {iPTH} at 6 and 36 months (mo) post-transplant. RESULTS: Median age was 12.8 (range: 1.9-20.5) years, and dialysis vintage was 11.2 (range: 0.0-112.9) months. The majority were of Hispanic and African Ancestry (77.3%). Median post-transplant iPTH was 69.5 (range: 1.8-306.8) pg/ml at 6 mo with a gradual downward trend to 59.0 (range: 28.0-445.0) pg/ml at 36 mo. Significant multivariable predictors of higher log {iPTH} post-transplant included longer dialysis vintage, higher TB, and lower log{eGFR} at 6 mo, and higher TB, lower log{eGFR}, and deceased donor transplant at 36 mo. CONCLUSIONS: Recognition of risk factors for HPT and monitoring iPTH post-transplant may facilitate timely interventions to mitigate cardiovascular and bone disease in pediatric KTx recipients. KEY MESSAGE: Describe serial trends in intact PTH after kidney transplantation. Pre- and post-transplant factors that contribute to persistence or re-occurrence of hyperparathyroidism after kidney transplantation in children include longer dialysis vintage, high pre-transplant treatment burden and decreased post-transplant GFR. Recognition of these factors, and monitoring intact PTH after kidney transplantation, could facilitate timely interventions to mitigate cardiovascular and bone disease in children.

PTH and the Regulation of Mesenchymal Cells within the Bone Marrow Niche.

Parathyroid hormone (PTH) plays a pivotal role in maintaining calcium homeostasis, largely by modulating bone remodeling processes. Its effects on bone are notably dependent on the duration and frequency of exposure. Specifically, PTH can initiate both bone formation and resorption, with the outcome being influenced by the manner of PTH administration: continuous or intermittent. In continuous administration, PTH tends to promote bone resorption, possibly by regulating certain genes within bone cells. Conversely, intermittent exposure generally favors bone formation, possibly through transient gene activation. PTH's role extends to various aspects of bone cell activity. It directly influences skeletal stem cells, osteoblastic lineage cells, osteocytes, and T cells, playing a critical role in bone generation. Simultaneously, it indirectly affects osteoclast precursor cells and osteoclasts, and has a direct impact on T cells, contributing to its role in bone resorption. Despite these insights, the intricate mechanisms through which PTH acts within the bone marrow niche are not entirely understood. This article reviews the dual roles of PTH-catabolic and anabolic-on bone cells, highlighting the cellular and molecular pathways involved in these processes. The complex interplay of these factors in bone remodeling underscores the need for further investigation to fully comprehend PTH's multifaceted influence on bone health.

The application of autofluorescence system contributes to the preservation of parathyroid function during thyroid surgery.

PURPOSE: The purpose of this study was to investigate the impact of autofluorescence technology on postoperative parathyroid function and short-term outcomes in patients undergoing thyroid surgery. METHODS: A total of 546 patients were included in the study, with 287 in the conventional treatment group and 259 in the autofluorescence group. Both groups underwent central lymph node dissection, which is known to affect parathyroid function. Short-term outcomes, including rates of postoperative hypocalcemia and parathyroid dysfunction, serum calcium and PTH levels on the first postoperative day, as well as the need for calcium supplementation, were analyzed. A multivariable analysis was also conducted to assess the impact of autofluorescence on postoperative parathyroid dysfunction, considering factors such as age, BMI, and preoperative calcium levels. RESULTS: The autofluorescence group demonstrated significantly lower rates of postoperative hypocalcemia and parathyroid dysfunction compared to the conventional treatment group. The autofluorescence group also had better serum calcium and PTH levels on the first postoperative day, and a reduced need for calcium supplementation. Surprisingly, the use of autofluorescence technology did not prolong surgical time; instead, it led to a shorter hospitalization duration. The multivariable analysis showed that autofluorescence significantly reduced the risk of postoperative parathyroid dysfunction, while factors such as age, BMI, and preoperative calcium levels did not show a significant correlation. CONCLUSION: This study provides evidence that autofluorescence technology can improve the preservation of parathyroid function during thyroid surgery, leading to better short-term outcomes and reduced postoperative complications. The findings highlight the potential of autofluorescence as a valuable tool in the management of parathyroid hypofunction. Further research and validation are needed to establish the routine use of autofluorescence technology in the thyroid.

ß-Receptor blocker enhances the anabolic effect of PTH after osteoporotic fracture.

The autonomic nervous system plays a crucial role in regulating bone metabolism, with sympathetic activation stimulating bone resorption and inhibiting bone formation. We found that fractures lead to increased sympathetic tone, enhanced osteoclast resorption, decreased osteoblast formation, and thus hastened systemic bone loss in ovariectomized (OVX) mice. However, the combined administration of parathyroid hormone (PTH) and the ß-receptor blocker propranolol dramatically promoted systemic bone formation and osteoporotic fracture healing in OVX mice. The effect of this treatment is superior to that of treatment with PTH or propranolol alone. In vitro, the sympathetic neurotransmitter norepinephrine (NE) suppressed PTH-induced osteoblast differentiation and mineralization, which was rescued by propranolol. Moreover, NE decreased the PTH-induced expression of Runx2 but enhanced the expression of Rankl and the effect of PTH-stimulated osteoblasts on osteoclastic differentiation, whereas these effects were reversed by propranolol. Furthermore, PTH increased the expression of the circadian clock gene Bmal1, which was inhibited by NE-ßAR signaling. Bmal1 knockdown blocked the rescue effect of propranolol on the NE-induced decrease in PTH-stimulated osteoblast differentiation. Taken together, these results suggest that propranolol enhances the anabolic effect of PTH in preventing systemic bone loss following osteoporotic fracture by blocking the negative effects of sympathetic signaling on PTH anabolism.

The biological variation of serum 1,25-dihydroxyvitamin D and parathyroid hormone, and plasma fibroblast growth factor 23 in healthy individuals.

BACKGROUND AND AIMS: Measuring 1,25-dihydroxyvitamin D (1,25(OH)2D), parathyroid hormone 1-84 (PTH 1-84) and intact FGF23 (iFGF23) is crucial for diagnosing a variety of diseases affecting bone and mineral homeostasis. Biological variability (BV) data are important for defining analytical quality specifications (APS), the usefulness of reference intervals, and the significance of variations in serial measurements in the same subject. The aim of this study was to pioneer the provision of BV estimates for 1,25(OH)2D and to improve existing BV estimates for iFGF23 and PTH 1-84. MATERIALS AND METHODS: Serum and plasma-EDTA samples of sixteen healthy subjects have been collected for seven weeks and measured in duplicate by chemiluminescent immunoassay on the DiaSorin Liaison platform. After variance verification, within-subject (CVI) and between-subject (CVG) BV estimates were assessed by either standard ANOVA, or CV-ANOVA. The APSs were calculated according to the EFLM-BV-model. RESULTS: We found the following CVI estimates with 95% confidence intervals:1,25(OH)2D, 22.2% (18.9-26.4); iFGF23, 16.1% (13.5-19.5); and PTH 1-84, 17.9% (14.8-21.8). The CVG were: 1,25(OH)2D, 21.2% (14.2-35.1); iFGF23, 21.1% (14.5-35.8); and PTH 1-84, 31.1% (22.1-50.8). CONCLUSIONS: We report for the first time BV estimates for 1,25(OH)2D and enhance existing data about iFGF23-BV and PTH 1-84-BV through cutting-edge immunometric methods.

Don't chase the adenoma: A probabilistic approach to imaging before parathyroidectomy.

BACKGROUND: Preoperative imaging before parathyroidectomy can localize adenomas and reduce unnecessary bilateral neck explorations. We hypothesized that (1) the utility of preoperative imaging varies substantially depending on the preoperative probability of having adenoma(s) and (2) that a selective imaging approach based on this probability could avoid unnecessary patient costs and radiation. METHODS: We analyzed 3,577 patients who underwent parathyroidectomy for primary hyperparathyroidism from 2001 to 2022. The predicted probability of patients having single or double adenoma versus hyperplasia was estimated using logistic regression. We then estimated the relationship between the predicted probability of single/double adenoma and the likelihood that sestamibi or 4-dimensional computed tomography was helpful for operative planning. Current Medicare costs and published data on radiation dosing were used to calculate costs and radiation exposure from non-helpful imaging. RESULTS: The mean age was 62 ± 13 years; 78% were women. Adenomas were associated with higher mean calcium (11.2 ± 0.74 mg/dL) and parathyroid hormone levels (140.6 ± 94 pg/mL) than hyperplasia (9.8 ± 0.52 mg/dL and 81.4 ± 66 pg/mL). The probability that imaging helped with operative planning increased from 12% to 65%, as the predicted probability of adenoma increased from 30% to 90%. For every 10,000 patients, a selective approach to imaging that considered the preoperative probability of having adenomas could save patients up to $3.4 million and >239,000 millisieverts of radiation. CONCLUSION: Rather than imaging all patients with primary hyperparathyroidism, a selective strategy that considers the probability of having adenomas could reduce costs and avoid excess radiation exposure.

Surgical treatment of secondary hyperparathyroidism in children with chronic kidney disease. Experience in 19 patients.

OBJECTIVES: Secondary hyperparathyroidism (sHPT) is an important contributor to bone disease and cardiovascular calcifications in children with chronic kidney disease (CKD). When conservative measures are ineffective, parathyroidectomy is indicated. The aim of our study was to evaluate the efficacy and safety of subtotal parathyroidectomy (sPTX) in pediatric and adolescent patients, and to provide a rationale for considering this aggressive treatment in CKD patients with uncontrolled sHPT. METHODS: We retrospectively analyzed the medical records of 19 pediatric CKD patients on dialysis with refractory sHPT who underwent sPTX at our institution between 2010 and 2020. All patients had clinical, radiological, and biochemical signs of renal osteodystrophy. RESULTS: One year after sPTX, parathyroid hormone (PTH) levels (median and interquartile range (IQR)) dropped from 2073 (1339-2484) to 164 (93-252) pg/mL (p=0.0001), alkaline phosphatase (ALP) levels from 1166 (764-2373) to 410 (126-421) IU/L (p=0.002), and the mean (±SDS) calcium-phosphate (Ca*P) product from 51±11 to 41±13 mg2/dL2 (p=0.07). Postoperatively, all patients presented with severe hungry bone syndrome (HBS) and required intravenous and oral calcium and calcitriol supplementation. None of them had other postoperative complication. Histological findings had a good correlation with preoperative parathyroid ultrasound imaging (n: 15) in 100 % and with technetium-99m (99mTc) sestamibi scintigraphy (n: 15) in 86.6 %. Clinical and radiological signs of bone disease improved in all patients. CONCLUSIONS: Pediatric sPTX is effective and safe to control sHPT and calcium-phosphate metabolism in children with CKD on dialysis and may mitigate irreversible bone deformities and progression of cardiovascular disease.

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.

The molecular sociology of NHERF1 PDZ proteins controlling renal hormone-regulated phosphate transport.

Parathyroid hormone (PTH) and fibroblast growth factor-23 (FGF23) control extracellular phosphate levels by regulating renal NPT2A-mediated phosphate transport by a process requiring the PDZ scaffold protein NHERF1. NHERF1 possesses two PDZ domains, PDZ1 and PDZ2, with identical core-binding GYGF motifs explicitly recognizing distinct binding partners that play different and specific roles in hormone-regulated phosphate transport. The interaction of PDZ1 and the carboxy-terminal PDZ-binding motif of NPT2A (C-TRL) is required for basal phosphate transport. PDZ2 is a regulatory domain that scaffolds multiple biological targets, including kinases and phosphatases involved in FGF23 and PTH signaling. FGF23 and PTH trigger disassembly of the NHERF1-NPT2A complex through reversible hormone-stimulated phosphorylation with ensuing NPT2A sequestration, down-regulation, and cessation of phosphate absorption. In the absence of NHERF1-NPT2A interaction, inhibition of FGF23 or PTH signaling results in disordered phosphate homeostasis and phosphate wasting. Additional studies are crucial to elucidate how NHERF1 spatiotemporally coordinates cellular partners to regulate extracellular phosphate levels.

A nomogram prediction model for hungry bone syndrome in dialysis patients with secondary hyperparathyroidism after total parathyroidectomy.

OBJECTIVE: Secondary hyperparathyroidism (SHPT) is a common complication of chronic kidney disease (CKD). Hungry bone syndrome (HBS) after parathyroidectomy (PTX) is a serious complication, which can lead to diarrhea, convulsion, arrhythmia and even death. This study was aimed to determine the risk factors for HBS after PTX in dialysis patients with SHPT and construct a nomogram prediction model to predict the incidence of postoperative complications. METHODS: Clinical data were collected from 80 maintenance hemodialysis (MHD) patients with SHPT who received total PTX in the Second Hospital of Jilin University from January 2018 to September 2021. In line with the inclusion and exclusion criteria, totally 75 patients were finally enrolled for analysis. Patients were divided into two groups for retrospective analysis according to the severity of postoperative HBS, including HBS group and non-HBS (N-HBS) group. Univariate and multivariate logistic regression analyses were conducted to determine the risk factors for postoperative HBS. Afterwards, the receiver operating characteristic (ROC) curves were plotted based on the statistical analysis results, aiming to compare the prediction effects of different predicting factors. Finally, the nomogram was established to evaluate the occurrence probability of postoperative complications predicted by the risk factors. RESULTS: Among the 75 patients, 32 had HBS (HBS group), while 43 did not have HBS (N-HBS group). Univariate analysis results indicated that, the preoperative intact parathyroid hormone (iPTH) and serum alkaline phosphatase (ALP) levels in HBS group were significantly higher than those in N-HBS group, while preoperative hemoglobin and preoperative albumin (Alb) levels were significantly lower than those in N-HBS group. As discovered by multivariate logistic regression analysis, preoperative iPTH (OR = 1.111, P = 0.029) and ALP (OR = 1.010, P < 0.001) were the independent risk factors for postoperative HBS. ROC curve analysis suggested that the area under the curve (AUC) values of these two indicators were 0.873 and 0.926, respectively (P < 0.0001). Subsequently, the nomogram model for predicting HBS was constructed. The model verification results indicated that the predicted values were basically consistent with the measured values, with the C-index of 0.943 (95% CI 0.892-0.994). Besides, the calibration curve was consistent with the ideal curve, demonstrating the favorable accuracy and discrimination of the model. CONCLUSIONS: Preoperative iPTH and preoperative ALP are the risk factors for postoperative HBS, which can be used to guide the early clinical intervention.