Prevalence of secondary hyperparathyroidism in patients with stage 3 and 4 chronic kidney disease seen in internal medicine

Large library docking identifies positive allosteric modulators of the calcium-sensing receptor

Positive allosteric modulator (PAM) drugs enhance the activation of the calcium-sensing receptor (CaSR) and suppress parathyroid hormone (PTH) secretion. Unfortunately, these hyperparathyroidism-treating drugs can induce hypocalcemia and arrhythmias. Seeking improved modulators, we docked libraries of 2.7 million and 1.2 billion molecules against the CaSR structure. The billion-molecule docking found PAMs with a 2.7-fold higher hit rate than the million-molecule library, with hits up to 37-fold more potent. Structure-based optimization led to nanomolar leads. In ex vivo organ assays, one of these PAMs was 100-fold more potent than the standard of care, cinacalcet, and reduced serum PTH levels in mice without the hypocalcemia typical of CaSR drugs. As determined from cryo-electron microscopy structures, the PAMs identified here promote CaSR conformations that more closely resemble the activated state than those induced by the established drugs.

Impact of successful secondary hyperparathyroidism treatment on cardiovascular morbidity in patients with chronic kidney disease KDIGO stages G3b-5

INTRODUCTION

Chronic kidney disease is common, with a projected increase to 5.4 million people in need of kidney replacement therapy by 2030. As many as 61.7% of patients on hemodialysis have secondary hyperparathyroidism (SHPT). This has been associated with high cardiovascular morbidity. The present study investigates the effect of SHPT treatment success on cardiovascular morbidity in patients with CKD KDIGO stages G3b, 4, and 5.

METHODS

A retrospective single center analysis of 211 chronic kidney disease stages G3b-5 patients undergoing computed tomography for coronary artery calcium (CAC) scoring at the University Hospital of Zurich between 2015 and 2019 was performed. The presence of and control of SHPT was assessed at the timepoint of CAC scoring and 6-12 months prior. Information on left ventricular ejection fraction (LVEF), left ventricular hypertrophy (LVH), and left ventricular myocardial mass index (LVMMI) were calculated from echocardiography values obtained at the timepoint of CAC scoring. Occurrence of major acute cardiovascular events, including acute coronary syndrome (ACS), within 1 year of CAC scoring was drawn from the charts. Independent predictive factors for ACS and LVH were assessed by multivariable analysis.

RESULTS

Thirty-four percent (n=72) of the patients had uncontrolled SHPT, whereas 66% (n=139) had either no (n=18%, n=39) or a controlled SHPT (n=48%, n=100). The CKD stage G3b-5 patients with uncontrolled SHPT had a significantly lower LVEF (p=0.028) and significantly more pronounced LVH (p=0.003) and a higher LVMMI (p=0.002) than the group with either no SHPT or well-controlled SHPT. Uncontrolled SHPT in the observed CKD cohort had a significantly higher risk for developing ACS (p=0.011, HR 2.76, 95%CI 1.26-6.05) compared to no or controlled SHPT patients (41.7% vs 31.7%). While patients with uncontrolled SHPT showed a median CAC score of 290 (IQR 18-866), those with no or controlled SHPT had a lower median CAC score of 194 (IQR 14-869), although not significant (p=0.490). Patients with CAC scores >400 displayed a significantly higher incidence of ACS (56.8% vs 33.1%, p=0.010).

CONCLUSIONS

SHPT is common (82%) in advanced CKD (≥G3b) patients and insufficiently controlled in one-third of patients. Insufficient control of SHPT is associated with higher cardiovascular morbidity, lower LVEF, increased LVH, and a higher incidence of ACS. Thus, increased focus on SHPT control in CKD patients may have a beneficial impact on cardiovascular outcomes.

Parathyroid hormone-PTH1R signaling in cardiovascular disease and homeostasis

Primary hyperparathyroidism (pHPT) afflicts our aging population with an incidence approaching 50 per 100 000 patient-years at a female:male ratio of ~3:1. Decisions surrounding surgical management are currently driven by age, hypercalcemia severity, presence of osteoporosis, renal insufficiency, or hypercalciuria with or without nephrolithiasis. Cardiovascular (CV) disease (CVD) is not systematically considered. This is notable since the parathyroid hormone (PTH) 1 receptor (PTH1R) is biologically active in the vasculature, and adjusted CV mortality risk is increased almost threefold in individuals with pHPT who do not meet contemporary recommendations for surgical cure. We provide an overview of epidemiology, pharmacology, and physiology that highlights the need to: (i) identify biomarkers that establish a healthy 'set point' for CV PTH1R signaling tone; (ii) better understand the pharmacokinetic-pharmacodynamic (PK-PD) relationships of PTH1R ligands in CV homeostasis; and (iii) incorporate CVD risk assessment into the management of hyperparathyroidism.

Persisting Hypercalcemia and Hyperparathyroidism after Kidney Transplantation Have a Negative Impact on Graft and Patient Survival

Hyperparathyroidism (HPT) with hypercalcemia, often deemed irreversible and detrimental to graft survival post-kidney transplantation (KT), prompts pre-transplant parathyroidectomy in hypercalcemic patients. In this retrospective analysis of 1212 kidney transplant recipients (KTRs) between 2006 and 2019, the incidence and effect of persistent HPT and hypercalcemia on graft and patient survival, and risk factors for persistence were analyzed until 60 months of follow up (FU). At KT, 5.7% (n = 69) had no HPT, 32.7% (n = 396) had HPT without hypercalcemia and 37.0% (n = 448) had HPT with hypercalcemia. At 2 years FU, 26.4% (n = 320) of patients had no HPT and 6% (n = 73) had HPT with hypercalcemia. Dialysis and dialysis duration were linked to HPT development, while dialysis, KT waiting time and donor type correlated with persisting hypercalcemia after KT. KTRs with normalized PTH and recovered hypercalcemia had improved death-censored graft survival (p < 0.001) and overall patient survival (p < 0.001). HPT with hypercalcemia is frequent at time of KT with normalization of PTH and calcium in a substantial proportion of patients after a KT. These findings question the routine pre-KT parathyroidectomy for suspected parathyroid autonomy. Persisting HPT, especially with hypercalcemia, adversely affects graft and patient survival, suggesting the need for more aggressive treatment of HPT, especially in cases of persisting hypercalcemia.

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.

Comparative analysis of clinicopathologic features between adenoma and hyperplasia in surgically treated patients for hyperparathyroidism: A retrospective study

BACKGROUND

Hyperparathyroidism (HPT) is a common endocrine disorder resulting from overproduction of parathyroid hormone (PTH). Usually HPT is caused by parathyroid adenoma (PA) or parathyroid hyperplasia (PH). Our aim is to assess clinicopathologic features associated with PA and PH in patients with HPT.

METHODS

We retrospectively collected 29 cases of HPT recorded at the Department of Pathology of Hassan II University Hospital of Fes, Morocco, from 2013 to 2016.

RESULTS

The mean age was 52.14 ± 15.7 years (range of 22-76 years), 13 patients (44.8%) had primary HPT, 16 (55.2%) had secondary HPT. The largest size of the resected parathyroid specimens ranged from 1 to 3.6 cm (mean of 2.26 ± 0.66 cm). Seventeen patients (58.6%) had PA, the remaining cases were diagnosed as PH. There were no significant statistical differences between PA and PH in age, sex, clinical presentation, preoperative serum PTH, or in parathyroid gland size (P > 0.05). However compared to PH, PA is more often a single-gland disease, found in primary HPT with higher preoperative calcium level (P ˂ 0.05).

CONCLUSIONS

In patients surgically treated for HPT, PA is associated with some distinctive clinicopathologic features. These findings could be helpful to pathologists and clinicians for appropriate clinicopathologic management.

Secondary hyperparathyroidism and adverse health outcomes in adults with chronic kidney disease

BACKGROUND

Secondary hyperparathyroidism (sHPT) develops frequently in patients with chronic kidney disease (CKD). However, the burden and long-term impact of sHPT on the risk of adverse health outcomes are not well studied.

METHODS

We evaluated all adults receiving nephrologist care in Stockholm during 2006-11 who were not undergoing kidney replacement therapy and had not developed sHPT. Incident sHPT was identified by using clinical diagnoses, initiated medications or two consecutive parathyroid hormone (PTH) measurements ≥130 pg/mL. We characterized sHPT incidence by estimated glomerular filtration rate (eGFR) strata, evaluated clinical predictors and quantified the association between incident sHPT (time-varying exposure) and the risk of fractures, CKD progression, major adverse cardiovascular events (MACEs) and death.

RESULTS

We identified 2556 adults with CKD Stages 1-5 (mean age 66 years, 38% women), of whom 784 developed sHPT during follow-up. The incidence of sHPT increased with advancing CKD: from 57 cases/1000 person-years in CKD Stage G3 to 230 cases/1000 person-years in Stage G5. In multivariable analyses, low eGFR was the strongest sHPT predictor, followed by young age, male sex and diabetes. Incident sHPT was associated with a 1.3-fold (95% confidence interval 1.1-1.8) increased risk of death, a 2.2-fold (1.42-3.28) higher risk of MACEs, a 5.0-fold (3.5-7.2) higher risk of CKD progression and a 1.3-fold (1.5-2.2) higher risk of fractures. Results were consistent in stratified analyses and after excluding early events.

CONCLUSIONS

Our findings illustrate the burden of sHPT in advanced CKD and highlight the susceptibility for adverse outcomes of patients developing sHPT. This may inform clinical decisions regarding pre-sHPT risk stratification, PTH monitoring and risk-prevention strategies post-sHPT development.

Inhibition of autophagy with Chloroquine enhanced apoptosis induced by 5-aminolevulinic acid-photodynamic therapy in secondary hyperparathyroidism primary cells and organoids

Secondary hyperparathyroidism (SHPT), the most common complication in the later stage of chronic kidney disease (CKD), seriously affects quality of life and the survival time of patients. At present, the conventional drugs and surgical methods still cannot fully meet the needs of clinical treatment. It is quite significant to develop effective and minimally invasive treatment methods. 5-Aminolevulinic acid-mediated photodynamic therapy (5-ALA-PDT), an alternative treatment relying on light irradiation, photosensitizer, and oxygen to produce a series of cytotoxic effects on tissue, is a promising technique for treating SHPT. We have successfully cultivated SHPT primary cells and organoids, and further proved that the amount of 5-ALA transformed into protoporphyrin IX in a time- and concentration-dependent manner. Also, 5-ALA-PDT exerted a cytotoxic effect on both primary cells and organoids by the cell counting kit (CCK-8) assay. Mechanically, 5-ALA-PDT increased the number of autophagosomes, and autophagy- and apoptosis-related proteins were upregulated markedly by western-blotting. The autophagy inhibitor Chloroquine (CQ) significantly increased the proportion of apoptotic cells, while the autophagy inducer rapamycin decreased the inhibitory ability of 5-ALA-PDT in SHPT primary cells. In brief, 5-ALA-PDT exhibits a phototoxic effect on SHPT primary cells and organoids. Autophagy and apoptosis are involved in the mechanism, and autophagy plays a role in promoting survival and inhibiting apoptosis. Therefore, the use of autophagy inhibitors can increase the sensitivity of SHPT cells and organoids treated with 5-ALA-PDT.

Surgical Management of Secondary Hyperparathyroidism

Secondary hyperparathyroidism (SHPT) affects a majority of patients with chronic kidney disease (CKD) of stage 3 or worse. Despite the development of calcimimetics and their effectiveness in treating SHPT, many patients continue to fail medical management and should be referred to a parathyroid surgeon. In this narrative review, we summarize the indications for surgical referral, preoperative planning, intraoperative strategies to guide resection, and postoperative management. In the absence of universal guidelines, it can be difficult to determine when it is appropriate to make this referral. The majority of studies evaluating parathyroidectomy (PTX) for SHPT use the criteria of parathyroid hormone level (PTH) >800 pg/ml with hypercalcemia and/or hyperphosphatemia, which may be accompanied by symptoms such as bone pain and pruritis that can improve after surgery. Although the reported utility of the various imaging modalities (i.e., 99m-technetium-sestamibi scintigraphy with computed tomography [SPECT/CT], CT, or ultrasound) is highly variable in SHPT, SPECT/CT appears to be the most sensitive. Intraoperatively, PTH monitoring is effective in predicting long-term cure of SHPT but not in predicting hypoparathyroidism. Ectopic and supernumerary parathyroid glands are common in these patients and are often implicated in persistent or recurrent disease. Postoperatively, patients are at risk of severe hypocalcemia and hungry bone syndrome requiring close monitoring and replenishment.

The Emerging Role of Nutritional Vitamin D in Secondary Hyperparathyroidism in CKD

In chronic kidney disease (CKD), hyperphosphatemia induces fibroblast growth factor-23 (FGF-23) expression that disturbs renal 1,25-dihydroxy vitamin D (1,25D) synthesis; thereby increasing parathyroid hormone (PTH) production. FGF-23 acts on the parathyroid gland (PTG) to increase 1α-hydroxylase activity and results in increase intra-gland 1,25D production that attenuates PTH secretion efficiently if sufficient 25D are available. Interesting, calcimimetics can further increase PTG 1α-hydroxylase activity that emphasizes the demand for nutritional vitamin D (NVD) under high PTH status. In addition, the changes in hydroxylase enzyme activity highlight the greater parathyroid 25-hydroxyvitmain D (25D) requirement in secondary hyperparathyroidism (SHPT); the higher proportion of oxyphil cells as hyperplastic parathyroid progression; lower cytosolic vitamin D binding protein (DBP) content in the oxyphil cell; and calcitriol promote vitamin D degradation are all possible reasons supports nutritional vitamin D (NVD; e.g., Cholecalciferol) supplement is crucial in SHPT. Clinically, NVD can effectively restore serum 25D concentration and prevent the further increase in PTH level. Therefore, NVD might have the benefit of alleviating the development of SHPT in early CKD and further lowering PTH in moderate to severe SHPT in dialysis patients.

Secondary hyperparathyroidism prevalence and profile, between diabetic and non-diabetic patients with stage 3 to 4 chronic kidney disease attended in internal medicine wards. MiPTH study

AIMS

Secondary hyperparathyroidism (SHPTH) is a leading cause of renal osteodystrophy, and an independent risk factor for all-cause and cardiovascular mortality. Our aim is to establish differences in prevalence and profile of SHPTH, regarding diabetics or non-diabetics with chronic kidney disease (CKD).

METHODS

Cross-sectional multicenter study which included patients with stages 3 to 4 CKD. SHPTH was considered when the intact PTH levels (iPTH) were equal or higher than 70pg/ml. We divided the sample into two groups (diabetics and non-diabetics). We used robust statistical methods.

RESULTS

409 patients (214 diabetics) were studied. HPTH was found in 60.4% of diabetics vs 65% of non-diabetics (P=0.42). Diabetics with HPTH were younger (79.5 vs 82.3 years-old, P=0.005), and had more hypertension (P=0.0014), dyslipidemia (P=0.0001) and comorbidities. In multivariate analysis, we found a significant relationship in case of diabetics, with age (OR: 1.04, 95%CI 1.005-1.09 P=0.02 ), and with statins treatment (OR 2.3, 95%CI 1.17-4.54, P=0.01).

DISCUSSION

The prevalence of SHPTH between the groups was similar, however, diabetics had more presence of hypertension and dyslipidemia, and SHPTH in this case was also related with moderate microalbuminuria and lower levels of vitamin D. An association with statins was also found in this group.