Diseases of the parathyroid gland in chronic kidney disease

Teriparatide and etelcalcetide improve bone, fibrosis, and fat parameters in chronic kidney disease model rats

Objectives

Chronic kidney disease (CKD) complicated by secondary hyperparathyroidism (SHPT) is associated with an increased risk of fragility fractures. Etelcalcetide (EC) is a treatment for SHPT that reduces serum parathyroid hormone (PTH) levels. However, the effects of combined treatment with osteoporosis drugs such as teriparatide (TPTD) remain unclear. This study investigates the combined effects of EC and TPTD on bone in CKD model rats.

Methods

The CKD model was established in 8-week-old male Wistar rats by feeding them a 0.75% adenine diet for 4 weeks. At 20 weeks of age, the rats were divided into 4 groups (N = 9-10 in each group): CKD group (vehicle administration), TPTD group (30 μg/kg, 3 times/week), EC group (0.6 mg/kg, daily), and Comb group (TPTD and EC combined). EC was injected for 12 weeks starting at 20 weeks of age, and TPTD was injected for 8 weeks starting at 24 weeks of age. After treatment, the followings were evaluated: bone mineral density, bone strength, biochemical tests, bone and fat histomorphometry, and micro-computed tomography.

Results

In CKD model rats, the combination of EC and TPTD was more effective in increasing cortical bone thickness and bone strength and inhibiting porosity. In addition, the combined treatment decreased bone marrow adiposity and fibrosis, and it increased bone mass and improved bone microstructure in trabecular bone.

Conclusions

With the observed benefits such as improved bone mass, bone strength, structural properties, and bone marrow adiposity, combination therapy may be a potential way to improve bone fragility in CKD.

RNA-Seq-based transcriptomics analysis during the photodynamic therapy of primary cells in secondary hyperparathyroidism

BACKGROUND

The aim of this study was to identify changes in gene expression before and after 5-aminolevulinic acid-mediated photodynamic therapy (5-ALA-PDT) and to investigate the potential mechanism of 5-ALA-PDT based on ribonucleic acid sequencing (RNA-Seq) analysis.

METHODS

Secondary hyperparathyroidism (SHPT) primary cells were isolated from surgically excised specimens and exposed to laser light. The transcription profiles of SHPT primary cells were identified through RNA-Seq. Differentially expressed genes (DEGs) were identified. Enrichment of functions and signaling pathway analysis were performed based on Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. Quantitative real-time polymerase chain reaction (RT-qPCR) and western blot analysis were used to validate genes based on RNA-Seq results.

RESULTS

In total, 1320 DEGs were identified, of which 1019 genes were upregulated and 301 genes were downregulated. GO and KEGG pathway analyses identified significantly enriched pathways in DEGs, including TGF beta in extracellular matrix (ECM), negative regulation of triglyceride biosynthetic process, protein heterodimerization activity, systemic lupus erythematosus, ECM-receptor interaction, focal adhesion and protein digestion and absorption. Protein-protein interaction (PPI) network analyses identified potential heat shock protein (HSP) interactions among the DEGs. Eight HSP genes were also identified that were most likely involved in 5-ALA-PDT, which were further validated by RT-qPCR and western blotting.

CONCLUSIONS

The findings of this descriptive study reveal changes in the transcriptome profile during 5-ALA-PDT, suggesting that gene expression and mutation, signaling pathways, and the molecular network are altered in SHPT primary cells. The above findings provide new insight for further studies on the mechanisms underlying 5-ALA-PDT in SHPT.

A retrospective case series of the treatment of spontaneous quadriceps tendon rupture in patients with uremia and secondary hyperparathyroidism

Background

Spontaneous quadriceps tendon rupture (QTR) is a rare complication of uremia. Secondary hyperparathyroidism (SHPT) is considered the leading cause of QTR in uremia patients. QTR in patients with uremia and SHPT are treated with active surgical repair along with the treatment of SHPT using medication or parathyroidectomy (PTX). The impact of PTX for SHPT on tendon healing remains unclear. The purpose of this study was to introduce surgical procedures for QTR and to determine the functional recovery of the repaired quadriceps tendon (QT) after PTX.

Methods

Between Jan 2014 and Dec 2018, eight uremia patients underwent PTX after a ruptured QT was repaired by figure-of-eight trans-osseous sutures with an overlapping tightening suture technique. Biochemical indices were measured before and one year after PTX to evaluate the control of SHPT. The changes in bone mineral density (BMD) were determined by comparing x-ray images at pre-PTX and during follow-up. The assessment of the functional recovery of the repaired QT was conducted at the last follow-up using multiple functional parameters.

Results

Eight patients (fourteen tendons) were retrospectively evaluated at an average follow-up of 3.46 ± 1.37 years after PTX. ALP and iPTH levels one year after PTX were significantly lower than at pre-PTX (P = 0.017, P < 0.001, respectively). Although there was no statistical differences compared to pre-PTX, serum phosphorus levels decreased and returned to normal one year after PTX (P = 0.101). BMD significantly increased at the last follow-up compared to pre-PTX. The average Lysholm score was 73.5 ± 11.07 and the average Tegner activity score was 2.63 ± 1.06. The active knee ROM after repair averaged an extension of 2.85 ± 3.78° to a flexion angle of 113.21 ± 10.12°. The quadriceps muscle strength was grade IV and the mean Insall-Salvati index was 0.93 ± 0.10 in all of the knees with tendon ruptures. All patients were able to walk without external help.

Conclusions

Figure-of-eight trans-osseous sutures with an overlapping tightening suture technique is an economical and effective treatment for spontaneous QTR in patients with uremia and SHPT. PTX may promote tendon-bone healing in patients with uremia and SHPT.

Predictive factors requiring high-dose evocalcet in hemodialysis patients with secondary hyperparathyroidism

The dosage of evocalcet required to control serum parathyroid hormone (PTH) levels varies among secondary hyperparathyroidism (SHPT) patients. This post hoc analysis evaluated the dose-dependent efficacy of evocalcet on serum intact PTH (iPTH) levels, corrected calcium (Ca) and phosphate (P) levels, and safety, in an evaluation period (week 28 to week 30) by stratifying the previous phase 3 data with the final evocalcet dosages (low 1-2 mg [131 patients], medium 3-4 mg [90 patients], high 5-8 mg [92 patients]), and identified pre-treatment patient characteristics predicting the use of higher final evocalcet dosages via univariate and multivariate logistic regression models. At the end of the study at week 30, the median serum iPTH level was higher and the achievement ratio for the target range of Japanese Society for Dialysis Therapy (60-240 pg/mL) was lower in the final high-dose subgroup (216 pg/mL and 58%, respectively) than in the other subgroups (low: 149 pg/mL and 79%; medium: 149 pg/mL and 73%, respectively). Among the three subgroups, the mean serum corrected Ca and P levels demonstrated similar trends, and similar ratio of patients achieved the target range (corrected Ca, 8.4-10 mg/dL; P, 3.5-6.0 mg/dL) from week 28 to week 30. No dose-dependent safety concerns were identified. Younger age, prior cinacalcet use, higher serum levels of iPTH and corrected Ca, procollagen type 1 N-terminal propeptide, intact fibroblast growth factor-23, and larger maximum parathyroid gland volume were significantly associated with final high-dose evocalcet (p < 0.05 in all cases). Patients requiring final high-dose evocalcet had pre-treatment characteristics indicating severe SHPT, leading to a lower final achievement rate for the target PTH levels of Japanese Society for Dialysis Therapy. Therefore, the early initiation of evocalcet treatment for SHPT is critical. Trial registration: This trial was registered as follows: ClinicalTrials.gov: NCT02549391 and JAPIC: JapicCTI-153013.

First-in-Human Phase I Study of the Novel Injectable Calcimimetic Agent Upacicalcet in Healthy Adult Japanese Participants

Background and Objective

Upacicalcet sodium hydrate is a novel small-molecule calcimimetic and has potential as a therapeutic agent for secondary hyperparathyroidism. We assessed the pharmacokinetics, pharmacodynamics, safety, and tolerability of a single intravenous dose of upacicalcet in Japanese healthy adults.

Method

This was a single-center, double-blinded, randomized, placebo-controlled, dose-escalation study. For each cohort, eight subjects were randomly assigned at a ratio of 3:1 to receive a single injection of placebo or upacicalcet 0.01, 0.1, 1.0, or 2.5 mg.

Result

The plasma concentration of upacicalcet increased in a dose-dependent manner. Upacicalcet rapidly disappeared from plasma after administration. The half-life of upacicalcet was approximately 1–2 h. The major excretion route of upacicalcet was via urine. Serum intact parathyroid hormone decreased in accordance with the upacicalcet dose, from the lowest dose of 0.01 mg. Gastrointestinal disorders occurred in one patient in the 1.0 mg group and in five patients in the 2.5 mg group. All adverse events were nonserious, and no symptomatic hypocalcemia occurred.

Conclusion

This study showed that upacicalcet acted as a calcimimetic and was excreted in the urine unchanged with little metabolism. Moreover, upacicalcet is a small molecule and has a small volume of distribution. In addition, less than 50% of upacicalcet binds to human plasma proteins. These findings suggest that upacicalcet administered to patients undergoing hemodialysis might be expected to have a long excretion period and sustained pharmacological effect.

Efficacy of Evocalcet in Previously Cinacalcet-Treated Secondary Hyperparathyroidism Patients

Introduction

Evocalcet is a recently approved calcimimetic agent for secondary hyperparathyroidism (SHPT). In this study, the efficacy and safety of once-daily oral evocalcet were evaluated in patients without prior cinacalcet use (nonusers) and previously treated patients (users).

Methods

This post hoc analysis of a previous phase III head-to-head comparison study included SHPT patients treated with evocalcet with or without prior cinacalcet use. Endpoints included trends in the median intact and whole parathyroid hormone (PTH), mean corrected calcium, phosphate, and bone metabolic markers, and whole-to-intact PTH ratios throughout the 30-week study period; proportions of patients achieving target intact PTH, corrected calcium, and phosphate at weeks 28 to 30; and adverse drug reactions (ADRs).

Results

This study included 127 nonusers and 190 users with significant differences in age; duration of dialysis; use of intravenous vitamin D receptor activators; levels of intact PTH, corrected calcium, tartrate-resistant acid phosphatase 5b, procollagen type 1 N-terminal-propeptide; and largest parathyroid gland volume (P < 0.05 for all characteristics) between 2 groups at baseline. Users required higher evocalcet dosages than nonusers. Similar efficacy results were found in the 2 groups except for a significantly higher proportion of nonusers achieving the intact PTH target (81.6% vs 67.1%, difference [95% confidence interval], −14.5% [−24.59, −3.34]), and a significant reduction in largest parathyroid gland volume from week 0 to week 30 (−120.6 [567.2] mm³, P = 0.043). No difference was found in ADRs between the 2 groups.

Conclusion

Treatment with evocalcet is effective and safe irrespective of prior cinacalcet treatment in SHPT patients.

Calcium-mediated parathyroid hormone suppression test in uraemic secondary hyperparathyroidism

AIM

The present study aimed to investigate the value of calcium-mediated parathyroid hormone (PTH) suppression test in evaluating the autonomic secretory function of parathyroid, and the management of uraemic secondary hyperparathyroidism (SHPT).

METHODS

Calcium-mediated PTH suppression test was performed in dialysis with SHPT, who were candidates for parathyroidectomy from June 2017 to December 2019 in our hospital. The PTH inhibition rate (PTH-IR) was calculated, and the correlation between PTH-IR and clinical indicators was explored.

RESULTS

Fifty-one subjects were included. PTH-IR was negatively correlated with baseline PTH (r = -0.35, P = .012), it was also correlated with dialysis years, coronary artery calcification score (CACS) and parathyroid mass (r = -0.397, P = .004; r = -0.327, P = .028; r = -0.363, P = .015), which were not found for baseline PTH. Forty-four patients underwent surgical treatment. According to the histological results, 26 patients presented with parathyroid non-nodular hyperplasia, and 18 patients presented with parathyroid nodular hyperplasia. The mass of parathyroid of patients with nodular hyperplasia was higher than that of patients with non-nodular hyperplasia (ρ = 0.01). The difference of the PTH-IR was not found between the two groups (ρ = 0.296). During the test, the highest serum calcium was 2.9 ± 0.4 mmol/L, which dropped to normal at the end of the test.

CONCLUSION

Parathyroid hormone inhibition rate might be a useful indicator in evaluating the autonomic secretory function of parathyroid and the progression of SHPT on top of intact PTH. Calcium-mediated PTH suppression test was safe in uraemic SHPT patients, but need to monitor for transient hypercalcaemia.

Secondary hyperparathyroidism is associated with postpartum blood pressure in preeclamptic women and normal pregnancies

BACKGROUND

Preeclampsia has been associated with features of secondary hyperparathyroidism. In this study, we examine the relationships of calcium metabolism with blood pressure (BP) in preeclamptic women and in a control group of normal (NORM) pregnancies in the postpartum.

METHODS

Sixty-three consecutive preeclamptic women (age 35 ± 6 years) were studied 4 weeks after delivery. We collected clinical and lab information on pregnancy and neonates and measured plasma and urinary calcium and phosphate, plasma parathyroid hormone (PTH) and 25-hydroxy vitamin D [25(OH)D], and performed 24-h ambulatory BP monitoring. BP and calcium metabolism of 51 preeclamptic were compared with 17 NORM pregnant women that matched for age, race, and postpartum BMI.

RESULTS

25(OH)D deficiency (<10 ng/ml) was found in 3% of preeclamptic women, insufficiency (10-30 ng/ml) in 67%, and NORM values (31-100 ng/ml) in the remaining 30%. Elevated plasma PTH (≥79 pg/ml) was found in 24% of preeclamptic women who had 25(OH)D plasma levels of 21.4 ± 8.3 ng/ml. In these women, PTH levels was independently associated with 24-h SBP and DBP and daytime and night-time DBP. Prevalence of nondippers and reverse dippers was elevated (75% and 33%, respectively). No associations between calcium metabolism and neonates' characteristics of preeclamptic women were observed. Prevalence of vitamin D deficiency and insufficiency and of elevated plasma PTH levels were comparable in matched groups. Considering preeclamptic women and matched controls as a whole group, office SBP and DBP levels were associated with PTH independently of preeclampsia and other confounders.

CONCLUSION

Features of secondary hyperparathyroidism are common in the postpartum. Preeclampsia and increased PTH levels were both independent factors associated with increased BP after delivery, and both might affect the future cardiovascular risk of these women.

Critical analysis of the intraoperative parathyroid hormone decrease during parathyroidectomy for secondary and tertiary hyperparathyroidism

BACKGROUND

This study aims to determine whether intraoperative parathyroid hormone monitoring helps to predict early surgical outcomes in patients with renal hyperparathyroidism and evaluate the impact on decision making during surgery.

METHODS

A prospective study was conducted. Serial samples of the intraoperative parathyroid hormone were collected; 2 of these were taken before the excision, and 2 were taken after the planned parathyroid resection (10 minutes and 15 minutes). We tested the criterion of an intraoperative parathyroid hormone percentage decay ≥80% of the highest value of the basal samples as a predictor of success.

RESULTS

Of the 228 patients, parathyroidectomy achieved success in 92.1%. In patients with secondary hyperparathyroidism, the failure group showed a tendency to stabilize or even increase the intraoperative parathyroid hormone values from the 10-minute measure (577 pg/mL) to the 15-minute measure (535 pg/mL) (P = .903). Conversely, intraoperative parathyroid hormone continued to drop in those with a successful outcome: 245 pg/mL (10 minutes) and 206 pg/mL (15 minutes) (P < .001). The failure group had a significantly lower percentage decay (P < .001) from baseline when compared with the success group. The intraoperative parathyroid hormone influenced the surgical management in up to 7% of the cases. The intraoperative parathyroid hormone dosage method showed an accuracy of 86%, a sensitivity of 88%, and specificity of 67%.

CONCLUSION

In patients with renal hyperparathyroidism undergoing parathyroidectomy, the use of intraoperative parathyroid hormone may help to predict an early therapeutic outcome with high sensitivity and accuracy by indicating the operation's success when there is an 80% reduction of baseline intraoperative parathyroid hormone 15 minutes after removal of the enlarged glands, an associated continuous decrease in serum intraoperative parathyroid hormone levels between 10 and 15 minutes, and achievement of plasma target values <500 pg/mL.

Efficacy and Safety of Evocalcet Evaluated by Dialysate Calcium Concentration in Patients with Secondary Hyperparathyroidism Undergoing Hemodialysis

Purpose

Evocalcet is a novel oral calcimimetic drug that has demonstrated similar efficacy to cinacalcet in regulating serum parathyroid hormone (PTH), calcium, and phosphate levels, with fewer upper gastrointestinal tract-related adverse drug reactions (ADRs) in patients with secondary hyperparathyroidism undergoing hemodialysis in Japan. We investigated the efficacy and safety of once-daily oral evocalcet under different dialysate calcium concentrations.

Patients and Methods

A post hoc analysis by dialysate calcium concentration (2.5, 2.75, and 3.0 mEq/L) was performed using data from a previous Phase 3 study that included cinacalcet as an active control. Efficacy endpoints were the proportion of patients who achieved the target intact PTH levels of ≥60 and ≤240 pg/mL between Week 28 and Week 30; time-course changes in serum intact PTH; calcium and phosphorus levels, bone turnover markers, and fibroblast growth factor 23 (FGF23) over the 30-week study period. Safety endpoints were overall ADRs and hypocalcemia- and upper gastrointestinal tract-related ADRs.

Results

A total of 634 patients were included in the analysis. Levels of intact PTH, calcium, phosphate, bone turnover markers, and FGF23 showed improvement in all sub-groups, irrespective of dialysate calcium concentration. The incidence of upper gastrointestinal tract-related ADRs was significantly lower in the evocalcet group than the cinacalcet group with dialysate calcium concentrations of 2.75 and 3.0 mEq/L (p<0.05 for both concentrations).

Conclusion

Evocalcet was effective and safe in regulating the levels of serum intact PTH, calcium, and phosphate in patients with secondary hyperparathyroidism undergoing hemodialysis, irrespective of dialysate calcium concentration.

Parathyroid hormone-producing cells exist in adipose tissues surrounding the parathyroid glands in hemodialysis patients with secondary hyperparathyroidism

Possible ectopic parathyroid hormone (PTH) production in adipose tissues surrounding hyperplastic parathyroid glands was examined in patients with secondary hyperparathyroidism (SHPT). In vitro culture of adipose tissues from 31 patients excised during parathyroidectomy showed PTH secretion in 23 (74.2%) patients. In vitro PTH secretion was detected in adipose tissues adhered to the parathyroid glands from 22 (71.0%) patients, in not-adhered adipose from 11 (35.5%) and in the thymus from four (28.6%) patients. Immunohistochemistry revealed colonies of PTH- and GCM2-positive cells intricately intertwined with adipocytes in excised adipose tissues prior to culture. When pieces of parathyroid parenchyma from SHPT patients were transplanted into the thyroid of immunodeficient nude rats with induced SHPT, the transplants secreted human PTH for one to three-and-half months after transplantation and expressed adipocyte markers, PPARγ2 and perilipin A, that the transplants did not express prior to transplantation. These findings indicate the importance of thoroughly removing adipose tissues surrounding the parathyroid glands when performing parathyroidectomy. We speculate that these ectopic PTH-producing cells are parathyroid parenchymal cells pushed out from the glands along with adipocyte progenitors during nodular growth of hyperplastic parenchymal cells and that these cells proliferate in SHPT, forming colonies PTH-producing cells intricately intertwined with adipocytes.

Evocalcet: A New Oral Calcimimetic for Dialysis Patients With Secondary Hyperparathyroidism

Patients with chronic kidney disease often develop secondary hyperparathyroidism (SHPT), marked by high levels of circulating parathyroid hormone (PTH) and increased risk of morbidity and mortality. Patients with SHPT are treated with a therapeutic combination that commonly includes calcimimetics, which have recently become popular in clinical settings, and other agents such as vitamin D preparations. Calcimimetics are a drug class that reduces PTH levels by targeting the calcium‐sensing receptor. Cinacalcet, a representative calcimimetic, is widely used; however, a high incidence of upper gastrointestinal (GI) tract‐related adverse events (AEs) can result in insufficient dosage and poor long‐term compliance. The newly approved evocalcet has equivalent efficacy to cinacalcet at a lower clinical dose, with improved bioavailability, fewer upper GI tract‐related AEs, and fewer safety concerns. This review gives an overview of calcimimetic agents, with a special focus on evocalcet, and describes the clinical advantages of evocalcet in the treatment of dialysis patients with SHPT.

Effectiveness of cinacalcet treatment for secondary hyperparathyroidism on hospitalization: Results from the MBD-5D study

OBJECTIVES

To elucidate the effect of cinacalcet use on all-cause and cause-specific hospitalization outcomes using a prospective cohort of maintenance hemodialysis patients.

METHODS

We used data from a prospective cohort of Japanese hemodialysis patients with secondary hyperparathyroidism and examined baseline characteristics as well as longitudinal changes. All patients were cinacalcet-naïve at study enrollment. Further, we used a marginal structural model to account for time-varying confounders on cinacalcet initiation and hospitalization outcomes, and an Andersen-Gill-type recurrent event model to account for any recurring events of hospitalization in the outcome analysis using the weighted dataset.

RESULTS

Among the 3,276 patients, cinacalcet treatment was initiated in 1,384 patients during the entire follow-up. Cinacalcet users were slightly younger, included more patients with chronic glomerulonephritis and fewer patients with diabetes, were more likely to have a history of parathyroidectomy, and were more often used receiving vitamin D receptor activator, phosphate binders, and iron supplements. The overall hospitalization analysis yielded a hazard ratio (HR) of 0.97 (95% confidence interval [CI]: 0.80, 1.18). A trend toward a mild protective association was observed for cardiovascular-related hospitalizations (HR: 0.85; 95% CI: 0.64, 1.14). In the subgroup analysis, a protective association was seen due to cinacalcet use for infection-related hospitalizations in the lowest intact parathyroid hormone group (HR: 0.36; 95% CI: 0.14, 0.95).

CONCLUSIONS

Cinacalcet initiation in patients on maintenance hemodialysis had no effect on all-cause and cause-specific hospitalizations. Although the overall association was statistically not significant, cinacalcet may have a protective association on cardiovascular-related hospitalization in all patients and infection-related hospitalization in patient with low intact parathyroid hormone.

Pharmacokinetics of evocalcet in secondary hyperparathyroidism patients receiving hemodialysis: first-in-patient clinical trial in Japan

Purpose

Cinacalcet is a positive allosteric modulator of calcium-sensing receptors in the parathyroid gland and an effective treatment for secondary hyperparathyroidism. However, this agent has considerable side effects and dosage limitations, which impair effective treatment. Therefore, we investigated the pharmacokinetics, pharmacodynamics, and safety of the novel calcimimetic, evocalcet.

Patients and methods

This was a multicenter, open-label study of single oral doses of 1, 4, and 12 mg evocalcet using an intrapatient dose escalation protocol in 29 Japanese secondary hyperparathyroidism patients receiving hemodialysis. Pharmacokinetics was assessed by plasma evocalcet concentrations. Pharmacodynamic evaluations consisted of measuring intact parathyroid hormone, serum corrected calcium, and fibroblast growth factor 23 concentrations. Safety and tolerability were evaluated by the analysis of adverse events (AEs).

Results

After a single 1-, 4-, or 12-mg dose, plasma evocalcet levels increased dose proportionally in a linear manner. Pharmacodynamic analyses showed that evocalcet effectively reduced intact parathyroid hormone and serum corrected calcium levels in a dose-dependent manner. AEs occurred in 31.0%, 28.6%, and 38.5% of patients receiving a single dose of 1, 4, or 12 mg, respectively. Most AEs were mild in severity.

Conclusion

Evocalcet is effective in the short term, has linear pharmacokinetics, and is well tolerated as observed by the low incidence of AEs.

Pharmacodynamics of evocalcet for secondary hyperparathyroidism in Japanese hemodialysis patients

BACKGROUND

This study investigated the pharmacokinetics, pharmacodynamics, and safety of multiple doses of evocalcet in Japanese secondary hyperparathyroidism (SHPT) patients receiving hemodialysis.

METHODS

In this multicenter, open-label study, conducted between August 2013 and March 2014, 27 patients received multiple doses of 1 and 4 mg evocalcet for 14 days, followed by an extension period of multiple doses of 8 and 12 mg evocalcet for 7 days using an intra-patient dose escalation protocol. Pharmacodynamic parameters consisted of measurement of intact parathyroid hormone (PTH), serum-corrected calcium, serum phosphorus and intact fibroblast growth factor 23 concentrations. Safety was assessed by analysis of adverse events.

RESULTS

Plasma evocalcet levels reached steady state 3 days after the first day of administration. Pharmacodynamic analyses showed that evocalcet effectively reduced intact PTH and serum-corrected calcium levels. Adverse events (AEs) occurred in 29.6 and 62.5% of patients receiving multiple doses of 1 or 4 mg, respectively. The AE 'blood calcium decreased' occurred in eight patients (33.0%) after multiple doses of 4 mg. All events were mild, except for one patient with a moderate AE (abnormal liver function) and one patient with a severe adverse drug reaction (blood calcium decreased).

CONCLUSION

Multiple doses of evocalcet reduced intact PTH levels with a concomitant decrease in serum calcium levels. Evocalcet was well tolerated in SHPT patients receiving hemodialysis.

Total parathyroidectomy versus total parathyroidectomy with autotransplantation for secondary hyperparathyroidism: systematic review and meta-analysis

Background: Total parathyroidectomy (tPTX) and total parathyroidectomy with autotransplantation (tPTX + AT) are effective and inexpensive treatments for secondary hyperparathyroidism (sHPT), but we do not know which one is the optimal approach. Therefore, we undertook a meta-analysis to compare the safety and efficacy of these two surgical procedures.

Methodology: Studies published in English on PubMed, Embase and the Cochrane Library from inception to 27 September 2016 were searched systematically. Eligible studies comparing tPTX with tPTX + AT for sHPT were included and Review Manager v5.3 was used.

Results: Eleven studies were included in this meta-analysis. Ten cohort studies and one randomized controlled trial (RCT) involving 1108 patients with sHPT were identified. There was no significant difference in the prevalence of surgical complications (relative risk [RR], 1.71; 95% confidence interval [CI], 0.77–3.79; p = .19), all-cause mortality (RR, 0.68; 95% CI, 0.33–1.39; p = .29), sHPT persistence (RR, 3.81; 95% CI, 0.56–25.95; p = .17) or symptomatic improvement (RR, 1.02; 95% CI, 0.91–1.13; p = .79). tPTX could reduce the risk of sHPT recurrence (RR, 0.19; 95% CI, 0.09–0.41; p < .0001) and reoperation because of recurrence or persistence of sHPT (RR, 0.46; 95% CI 0.24–0.86; p = .01) compared with tPTX + AT. Simultaneously, tPTX increased the risk of hypoparathyroidism (RR, 2.63; 95% CI, 1.06–6.51; p = .04).

Conclusions: We found tPTX and tPTX + AT to be useful methods for sHPT treatment. tPTX was superior for reducing the risk of sHPT recurrence and reoperation than tPTX + AT but, due to a lack of high statistical-power RCTs, comparative studies will be needed in the future.

Critical Governance Issue of Parathyroid Hormone Assays and its Selection in the Management of Chronic Kidney Disease Mineral and Bone Disorders

Measurement of circulating parathyroid hormone (PTH) levels is essential for optimal management of mineral and bone disorders (MBD) in chronic kidney disease (CKD) patients. There are two major types of PTH assays currently in use: intact parathyroid hormone (i-PTH) and whole PTH (w-PTH) assays. The i-PTH assay is the current standard, and considerable information regarding the management of CKD-MBD has been obtained with this method. However, several limitations have been found with the i-PTH assay. One limitation is that i-PTH assay also measures fragments other than full-length PTH (1-84). Another limitation is the existence of multiple readout methods of the i-PTH assay. The w-PTH assay is theoretically ideal because it exclusively detects full-length PTH (1-84). However, clinical data proving the advantages of w-PTH measurement are not sufficient. For uremic patients, Kidney Disease Improving Global Outcomes suggest that PTH levels should be maintained within approximately two to nine times the upper normal limit of the i-PTH assays. The most critical issue in the evaluation of PTH levels is the lack of definitive PTH assay method. Evidence-based recommendations on clinical management goals of PTH are warranted.

Effects of parathyroidectomy on bone metabolism in haemodialysis patients with secondary hyperparathyroidism

OBJECTIVE

To evaluate the outcome of bone metabolism and bone mineral density (BMD) in haemodialysis patients after parathyroidectomy (PTX).

METHODS

A total of 31 haemodialysis patients with secondary hyperparathyroidism (SHPT) were treated with PTX. BMD of lumbar spine (LS) and femoral neck (FN) was determined by dual energy X-ray absorptiometry.

RESULTS

Parathyroidectomy ledds to significant decrease of serum β-crosslaps (β-CTX), osteocalcin (OC) and procollagen type I amino-terminal propeptide (PINP) while serum sclerostin (SOST) increased after surgery. BMD was markedly improved in both LS and FN after PTX. Z-scores analysis further confirmed that PTX significantly benefited bone metabolism in haemodialysis patients, which well correlated with the improvement of serum iPTH and OC.

CONCLUSIONS

Parathyroidectomy leads to significant improvement of serum OC, PINP, β-CTX and SOST, which may beneficially modify calcium-phosphorus metabolism and BMD in haemodialysis patients with SHPT.

Impact of Different Levels of iPTH on All-Cause Mortality in Dialysis Patients with Secondary Hyperparathyroidism after Parathyroidectomy

Background

Secondary hyperparathyroidism (SHPT) usually required parathyroidectomy (PTX) when drugs treatment is invalid. Analysis was done on the impact of different intact parathyroid hormone (iPTH) after the PTX on all-cause mortality.

Methods

An open, retrospective, multicenter cohort design was conducted. The sample included 525 dialysis patients with SHPT who had undergone PTX.

Results

404 patients conformed to the standard, with 36 (8.91%) deaths during the 11 years of follow-up. One week postoperatively, different levels of serum iPTH were divided into four groups: A: ≤20 pg/mL; B: 21–150 pg/mL; C: 151–600 pg/mL; and D: >600 pg/mL. All-cause mortality in groups with different iPTH levels appeared as follows: A (8.29%), B (3.54%), C (10.91%), and D (29.03%). The all-cause mortality of B was the lowest, with D the highest. We used group A as reference (hazard ratio (HR) = 1) compared with the other groups, and HRs on groups B, C, and D appeared as 0.57, 1.43, and 3.45, respectively.

Conclusion

The all-cause mortality was associated with different levels of iPTH after the PTX. We found that iPTH > 600 pg/mL appeared as a factor which increased the risk of all-cause mortality. When iPTH levels were positively and effectively reducing, the risk of all-cause mortality also decreased. The most appropriate level of postoperative iPTH seemed to be 21–150 pg/mL.

The impact of calcineurin inhibitors on neutrophil gelatinase-associated lipocalin and fibroblast growth factor 23 in long-term kidney transplant patients

BACKGROUND

Neutrophil gelatinase-associated lipocalin (NGAL), a protein with bacteriostatic functions rapidly excreted from stimulated or damaged epithelial cells, is elevated in acute and chronic kidney disease. A calcineurin dependent signaling pathway for fibroblast growth factor 23 (FGF23) has been revealed, but the effect of calcineurin inhibitors (CNIs) on the levels of NGAL and markers of mineral metabolism in long-term kidney transplant patients has not been explored.

METHODS

In a cross-sectional study, 39 patients who received a first kidney transplant more than 10 years ago were split into two groups based on whether (n=28) or not (n=11) they used CNIs. Only patients with well-functioning grafts defined as an estimated glomerular filtration rate ≥45 mL/min per 1.73 m² were included.

RESULTS

The median levels of NGAL, intact parathyroid hormone (iPTH), and iFGF23 were significantly higher in CNI users vs CNI nonusers, 167.0 (134.0-235.0) ng/mL vs 105.0 (91.3-117.0) ng/mL, P<.001, 13.8 (10.0-17.3) pmol/L vs 8.4 (6.4-9.9) pmol/L, P=.003, and 81.6 (56.4-116.5) pg/mL vs 61.8 (43.3-72.1) pg/mL, P=.04 respectively.

CONCLUSIONS

The median levels of iFGF23 were higher in CNI users compared to CNI nonusers giving support to the notion of a CNI induced FGF23 resistance in the parathyroid. The net result of CNIs side effects needs to be further explored.

Compared effects of calcium and sodium polystyrene sulfonate on mineral and bone metabolism and volume overload in pre-dialysis patients with hyperkalemia

BACKGROUND

Hyperkalemia is prevalent in end-stage renal disease patients, being involved in life-threatening arrhythmias. Although polystyrene sulfonate (PS) is commonly used for the treatment of hyperkalemia, direct comparison of effects between calcium and sodium PS (CPS and SPS) on mineral and bone metabolism has not yet been studied.

METHODS

In a randomized and crossover design, 20 pre-dialysis patients with hyperkalemia (>5 mmol/l) received either oral CPS or SPS therapy for 4 weeks.

RESULTS

After 4-week treatments, there was no significant difference of changes in serum potassium (K) from the baseline (ΔK) between the two groups. However, SPS significantly decreased serum calcium (Ca) and magnesium (Mg) and increased intact parathyroid hormone (iPTH) values, whereas CPS reduced iPTH. ΔiPTH was inversely correlated with ΔCa and ΔMg (r = -0.53 and r = -0.50, respectively). Furthermore, sodium (Na) and atrial natriuretic peptide (ANP) levels were significantly elevated in patients with SPS, but not with CPS, whereas ΔNa and ΔANP were significantly correlated with each other in all the patients. We also found that ΔNa and Δ(Na to chloride ratio) were positively correlated with ΔHCO₃^-. In artificial colon fluid, CPS increased Ca and decreased Na. Furthermore, SPS greatly reduced K, Mg, and NH₃.

CONCLUSION

Compared with SPS, CPS may be safer for the treatment of hyperkalemia in pre-dialysis patients, because it did not induce hyperparathyroidism or volume overload.

Chronic Kidney Disease-Mineral and Bone Disorder in Asia

BACKGROUND

Chronic kidney disease-mineral and bone disorder (CKD-MBD) is one of the most common complications in patients with CKD. As CKD-MBD is a systemic syndrome, prevention and management should be aimed at achieving better survival and less risk of cardiovascular events and fractures.

SUMMARY

Although target ranges for serum markers of mineral metabolism have been proposed in several global or local guidelines, these were mostly based on data from non-Asian patients. Additionally, there remain differences in medical and social systems as well as in economic status, even among Asian countries and areas.

KEY MESSAGE

Asian CKD patient data needs to be analyzed, published, and shared to establish optimal local strategies for CKD-MBD management.

Management of secondary hyperparathyroidism: how and why?

Secondary hyperparathyroidism (SHPT) is a common complication in chronic kidney disease. Currently, various treatment options are available, including vitamin D receptor activators, cinacalcet hydrochloride, and parathyroidectomy. These treatment options have contributed to the successful control of SHPT, and recent clinical studies have provided evidence suggesting that effective treatment of SHPT leads to improved survival. Although bone disease is the most widely recognized consequence of SHPT and remains a major target for treatment of SHPT, there is increasing evidence that parathyroid hormone (PTH) and fibroblast growth factor 23 (FGF23), both of which are markedly elevated in SHPT, have multiple adverse effects on extraskeletal tissues. These actions may lead to the pathological development of left ventricular hypertrophy, renal anemia, immune dysfunction, inflammation, wasting, muscle atrophy, and urate accumulation. Given that treatment of SHPT leads to decreases in both PTH and FGF23, these data provide an additional rationale for treating SHPT. However, definitive evidence is still lacking, and future research should focus on whether treatment of SHPT prevents the adverse effects of PTH and FGF23.

Feasibility of photodynamic therapy for secondary hyperparathyroidism in chronic renal failure rats

BACKGROUND

Feasibility of photodynamic therapy (PDT) for secondary hyperparathyroidism (SHPT) was examined in a rat model of SHPT.

METHODS

A photosensitizer, 5-aminolevulinic acid (5-ALA), was injected intraperitoneally, and the parathyroid glands were irradiated either after surgical exposure with 385-nm light or transdermally with 630-nm light from a light-emitting diode (LED) lamp.

RESULTS

PDT with high 5-ALA and irradiation doses caused severe hypoparathyroidism in SHPT rats within two days. Low-dose invasive PDT reduced intact parathyroid hormone (iPTH) levels in all rats from 748.9 ± 462.6 pg/mL at baseline to 138.7 ± 117.5 pg/mL at week 6, followed by a further decrease to 80.5 ± 54.0 pg/mL at week 9 in 60 % of rats or an increase to 970.0 ± 215.6 pg/mL at week 9 in 40 % of rats. Low-dose noninvasive PDT reduced iPTH levels from 1612.5 ± 607.8 pg/mL at baseline to 591.9 ± 480.1 pg/mL at week 4 in all rats. Thereafter, iPTH levels remained low in 43 % of rats and were 233.7 ± 51.6 pg/mL at week 9, whereas 57 % showed an increase, reaching 3305.9 ± 107.3 pg/mL at week 9. Control SHPT rats had iPTH levels of 2487.8 ± 350.9 and 2974.6 ± 372.1 pg/mL at week 4 and 9, respectively. The parathyroid glands of the rats with low iPTH levels were atrophied and had few parathyroid cells surrounded by fibrotic materials and no recognizable blood vessels. Those of the rats with high iPTH levels showed well-preserved gland structure, clusters of parathyroid cells, and blood vessels.

CONCLUSION

These results demonstrate that 5-ALA-mediated PDT for SHPT is feasible.

Once-weekly teriparatide in hemodialysis patients with hypoparathyroidism and low bone mass: a prospective study

Once-weekly 56.5-μg teriparatide treatment was significantly associated with the increase in lumbar spine bone mineral density at 48 weeks among hemodialysis patients with hypoparathyroidism and low bone mass; however, discontinuation of treatment because of adverse events was frequently observed. Careful monitoring for adverse events should be required.

INTRODUCTION

Once-weekly 56.5-μg teriparatide is reportedly effective for treating osteoporotic patients without renal insufficiency. However, little is known about the efficacy and safety of once-weekly teriparatide in hemodialysis patients.

METHODS

We conducted a 48-week prospective, observational cohort study including 22 hemodialysis patients aged 20 years or older with hypoparathyroidism and low bone mass who received once-weekly teriparatide at 56.5 μg at a tertiary care hospital between January 2013 and January 2015. Primary outcomes were within-subject percent changes of bone mineral density (BMD) at the lumbar spine, femoral neck, and distal one-third radius at 24 and 48 weeks. Secondary outcomes included percent changes of serum bone turnover markers (osteocalcin, bone-specific alkaline phosphatase (BAP), N-terminal propeptide of procollagen type 1 (P1NP), and tartrate-resistant acid phosphatase 5b (TRAP-5b)). Adverse events were evaluated.

RESULTS

The BMD increased at the lumbar spine by 3.3 ± 1.9 % (mean ± SEM) and 3.0 ± 1.8 % at 24 and 48 weeks but not in the femoral neck and distal one-third radius. Serum osteocalcin, BAP, and P1NP increased significantly at 4 weeks, maintaining higher concentrations up to 48 weeks, although TRAP-5b decreased gradually during treatment. The baseline BAP was significantly associated with the 48-week percent change in lumbar spine BMD. Transient hypotension was the most common adverse event. Ten patients discontinued treatment because of adverse events.

CONCLUSIONS

Once-weekly teriparatide was associated with increased lumbar spine BMD in hemodialysis patients with hypoparathyroidism and low bone mass. Careful monitoring should be required for treatment of such patients.

Comparative Proteome Analysis of hAT-MSCs Isolated from Chronic Renal Failure Patients with Differences in Their Bone Turnover Status

The relationship between the stem cells and the bone turnover in uremic bone disease due to chronic renal failure (CRF) is not described. The aim of this study was to investigate the effect of bone turnover status on stem cell properties. To search for the presence of such link and shed some light on stem-cell relevant mechanisms of bone turnover, we carried out a study with mesenchymal stem cells. Tissue biopsies were taken from the abdominal subcutaneous adipose tissue of a CRF patient with secondary hyperparathyroidism with the high turnover bone disease. This patient underwent parathyroidectomy operation (PTX) and another sample was taken from this patient after PTX. A CRF patient with adynamic bone disease with low turnover and a healthy control were also included. Mesenchymal stem cells isolated from the subjects were analyzed using proteomic and molecular approaches. Except ALP activity, the bone turnover status did not affect common stem cell properties. However, detailed proteome analysis revealed the presence of regulated protein spots. A total of 32 protein spots were identified following 2D gel electrophoresis and MALDI-TOF/TOF analyzes. The identified proteins were classified into seven distinct groups and their potential relationship to bone turnover were discussed. Distinct protein expression patterns emerged in relation to the bone turnover status indicate a possible link between the stem cells and bone turnover in uremic bone disease due to CRF.

Two Years of Cinacalcet Hydrochloride Treatment Decreased Parathyroid Gland Volume and Serum Parathyroid Hormone Level in Hemodialysis Patients With Advanced Secondary Hyperparathyroidism

The long-term effect of cinacalcet hydrochloride treatment on parathyroid gland (PTG) volume has been scarcely investigated in patients with moderate to advanced secondary hyperparathyroidism (SHPT). The present study was a prospective observational study to determine the effect of cinacalcet treatment on PTG volume and serum biochemical parameters in 60 patients with renal SHPT, already treated with intravenous vitamin D receptor activator (VDRA). Measurement of biochemical parameters and PTG volumes were performed periodically, which were analyzed by stratification into tertiles across the baseline parathyroid hormone (PTH) level or PTG volume. We also determined the factors that can estimate the changes in PTG volume and the achievement of the target PTH range by multivariable analyses. Two years of cinacalcet treatment significantly decreased the serum levels of PTH, calcium, and phosphate, followed by the improvement of achieving the target ranges for these parameters recommended by the Japanese Society for Dialysis Therapy. Cinacalcet decreased the maximal and total PTG volume by about 30%, and also decreased the serum PTH level independent of the baseline serum PTH level and PTG volume. Ten out of 60 patients showed 30% increase in maximal PTG after 2 years. Multivariable analysis showed that patients with nodular PTG at baseline and patients with higher serum calcium and PTH levels at 1 year were likely to exceed the target range of PTH at two years. In conclusion, cinacalcet treatment with intravenous VDRA therapy decreased both PTG volume and serum intact PTH level, irrespective of the pretreatment PTG status and past treatment history.

Parathyroid hormone and clinical outcome in kidney transplant patients with optimal transplant function

BACKGROUND

The aim of the study was to investigate whether serum levels of intact parathyroid hormone (iPTH) are associated with an increased risk of cardiovascular events, graft loss, or mortality in kidney transplant patients with optimal transplant function.

METHODS

From the Norwegian Renal Registry, we identified 522 patients who received a first kidney transplant from 2001 to 2008 with optimal transplant function defined as an estimated glomerular filtration rate (eGFR)≥60 mL/min/1.73 m2, more than one yr after transplantation. Cox's proportional hazard models were used to assess the association between iPTH measured 10 wk after transplantation and the composite endpoint. The estimates were adjusted for age, gender, serum calcium, serum phosphate, diabetes mellitus, cardiovascular disease, and time on dialysis prior to transplantation.

RESULTS

Median follow-up time was 3.9 yr (interquartile range, IQR: 2.0-6.0 yr). Patients in the third iPTH quartile (9.3-14.4 pM) had the lowest risk for reaching the composite endpoint. Patients in the fourth iPTH quartile (>14.4 pM) had an increased risk compared to those in the third quartile (HR: 2.60, 95% CI: 1.10-6.16, p=0.03).

CONCLUSION

In patients with optimal transplant function, iPTH levels are associated with a clinical outcome consisting of cardiovascular events, graft loss, and all-cause mortality.

Hyperparathyroidism in chronic kidney disease patients: an update on current pharmacotherapy

INTRODUCTION

Secondary hyperparathyroidism is the most common abnormalities of mineral metabolism in chronic kidney disease (CKD), which causes bone disease and vascular calcification, leading to increased risk of mortality.

AREAS COVERED

The aim of this review is to provide an overview of pharmacological therapies for secondary hyperparathyroidism, based on current understanding of the disease.

EXPERT OPINION

The initial event in the pathogenesis of secondary hyperparathyroidism is the phosphorus overload per nephron that lead to the secretion of a new phosphaturic hormone, fibroblast growth factor 23 from the bone. Such an abnormality develops very early in CKD, even without hyperphosphatemia. When hyperphosphatemia develops, phosphate binders are prescribed in many CKD patients. Non-calcium containing binders are gaining popularity because of less risk of excess calcium load; however, no specific superiority in patient-level outcomes has been fully established yet. For the direct control of parathyroid hormone secretion, cinacalcet hydrochloride has become widespread in addition to vitamin D receptor activators. As adverse events related to these therapeutic agents occur occasionally, however, and better adherence is one of the most important determinants of the benefits of the drugs, fewer adverse events as well as more potent therapeutic effects should be aimed in the development of new agents in future.

Efficacy of intraoperative parathyroid hormone monitoring to predict success of parathyroidectomy for secondary hyperparathyroidism

Purpose

In secondary hyperparathyroidism (sHPT), it is unclear which criterion for intraoperative parathyroid hormone (ioPTH) decline performs best and whether ioPTH monitoring is sufficiently efficacious in predicting postoperative surgical cure by retrospective review.

Methods

In 80 parathyroidectomies for sHPT, patients with ioPTH monitoring and follow-up PTH assay were categorized into physiologically accepted and failed groups. Receiver operating characteristic (ROC) curves were used to identify the criterion with the best performance and to determine the regression equation for prediction of surgical success.

Results

There was a statistically significant difference in the percentage reduction of ioPTHs between the two groups (P < 0.05). With our criterion, cure was predicted with a sensitivity of 86% and specificity that could be improved to 60% using an 85% ioPTH decrease as cut-off level when this value was compared to the Miami Criterion. There was a slightly negative correlation between the natural logarithm of percentage reduction of ioPTH and percentage reduction of PTH at follow-up (R² = 0.109, P = 0.003).

Conclusion

ioPTH measurements are a useful tool for improvement of the cure rate of operations for sHPT. Because this study aimed at 40 minutes (ioPTH3) as an optimal process in the operation, we recommend using a criterion of more than 85% ioPTH decline at 40 minutes by use of the ROC curve, and the use of the presently calculated regression equation may enable prediction of success.

Hypophosphatemic Osteomalacia Associated with Tenofovir: a Multidisciplinary Approach is Required

Tenofovir is widely used as first-line treatment of HIV infection, although its use is sometimes complicated by a reversible proximal renal tubulopathy.We report the case of a 45-year-old woman with chronic HIV infection and personality disorder, who after 12 months of tenofovir, complained of fatigue, diffuse bone pain and gait disturbances. The elevated level of alkaline phosphatase, hypophosphatemia and inappropriate phosphaturia suggested the diagnosis of hypophosphatemic osteomalacia secondary to proximal renal tubulopathy. A dual-energy x-ray absorptiometry showed a bone mineral density below the expected range for age (lumbar spine Z-score -3.3, femoral neck Z-score -2.1). A whole body (99m)Tc-methylene diphosphonate bone scan showed multiple areas of increased focal activity in the lumbar and thoracic spine and in sacroiliac and hip joints consistent with pseudofractures. Two months after tenofovir discontinuation and administration of vitamin D and phosphate, osteomalacia-related symptoms disappeared. Eleven months later, bone and mineral metabolism data were normal and bone scintigraphy did not show any pathological findings.This report highlights the importance of considering the diagnosis of osteomalacia in patients treated with tenofovir and emphasizes the need for monitoring alkaline phosphatase, blood and urinary phosphate and creatinine, especially in patients with risk factors for bone disease.