Paricalcitol versus calcitriol in the treatment of secondary hyperparathyroidism

Persistent uncertainties in optimal treatment approaches of secondary hyperparathyroidism and hyperphosphatemia in patients with chronic kidney disease

PURPOSE OF REVIEW

This review is a critical analysis of treatment results obtained in clinical trials conducted in patients with chronic kidney disease (CKD) and secondary hyperparathyroidism (SHPT), hyperphosphatemia, or both.

RECENT FINDINGS

Patients with CKD have a high mortality rate. The disorder of mineral and bone metabolism (CKD-MBD), which is commonly present in these patients, is associated with adverse outcomes, including cardiovascular events and mortality. Clinical trials aimed at improving these outcomes by modifying CKD-MBD associated factors have most often resulted in disappointing results. The complexity of CKD-MBD, where many players are closely interconnected, might explain these negative findings. We first present an historical perspective of current knowledge in the field of CKD-MBD and then examine potential flaws of past and ongoing clinical trials targeting SHPT and hyperphosphatemia respectively in patients with CKD.

Therapeutic approaches and novel antifibrotic agents in renal fibrosis: A comprehensive review

Renal fibrosis (RF) is one of the underlying pathological conditions leading to progressive loss of renal function and end-stage renal disease (ESRD). Over the years, various therapeutic approaches have been explored to combat RF and prevent ESRD. Despite significant advances in understanding the underlying molecular mechanism(s), effective therapeutic interventions for RF are limited. Current therapeutic strategies primarily target these underlying mechanisms to halt or reverse fibrotic progression. Inhibition of transforming growth factor-β (TGF-β) signaling, a pivotal mediator of RF has emerged as a central strategy to manage RF. Small molecules, peptides, and monoclonal antibodies that target TGF-β receptors or downstream effectors have demonstrated potential in preclinical models. Modulating the renin-angiotensin system and targeting the endothelin system also provide established approaches for controlling fibrosis-related hemodynamic changes. Complementary to pharmacological strategies, lifestyle modifications, and dietary interventions contribute to holistic management. This comprehensive review aims to summarize the underlying mechanisms of RF and provide an overview of the therapeutic strategies and novel antifibrotic agents that hold promise in its treatment.

Microbial bile acid metabolite ameliorates mycophenolate mofetil-induced gastrointestinal toxicity through vitamin D3 receptor

Mycophenolate mofetil (MMF) is one of the most used immunosuppressive drugs in organ transplantation, but frequent gastrointestinal (GI) side effects through unknown mechanisms limit its clinical use. Gut microbiota and its metabolites were recently reported to play a vital role in MMF-induced GI toxicity, but the specific mechanism of how they interact with the human body is still unclear. Here, we found that secondary bile acids (BAs), as bacterial metabolites, were significantly reduced by MMF administration in the gut of mice. Microbiome data and fecal microbiota transfer model supported a microbiota-dependent effect on the reduction of secondary BAs. Supplementation of the secondary BA lithocholic acid alleviated MMF-induced weight loss, colonic inflammation, and oxidative phosphorylation damage. Genetic deletion of the vitamin D3 receptor (VDR), which serves as a primary colonic BA receptor, in colonic epithelial cells (VDRΔIEC) abolished the therapeutic effect of lithocholic acid on MMF-induced GI toxicity. Impressively, we discovered that paricalcitol, a Food and Drug Administration-approved VDR agonist that has been used in clinics for years, could effectively alleviate MMF-induced GI toxicity. Our study reveals a previously unrecognized mechanism of gut microbiota, BAs, and VDR signaling in MMF-induced GI side effects, offering potential therapeutic strategies for clinics.

Paricalcitol Has a Potent Anti-Inflammatory Effect in Rat Endothelial Denudation-Induced Intimal Hyperplasia

Neointimal hyperplasia is the main cause of vascular graft failure in the medium term. Vitamin D receptor activation modulates the biology of vascular smooth muscle cells and has been reported to protect from neointimal hyperplasia following endothelial injury. However, the molecular mechanisms are poorly understood. We have now explored the impact of the selective vitamin D receptor activator, paricalcitol, on neointimal hyperplasia, following guidewire-induced endothelial cell injury in rats, and we have assessed the impact of paricalcitol or vehicle on the expression of key cell stress factors. Guidewire-induced endothelial cell injury caused neointimal hyperplasia and luminal stenosis and upregulated the expression of the growth factor growth/differentiation factor-15 (GDF-15), the cytokine receptor CD74, NFκB-inducing kinase (NIK, an upstream regulator of the proinflammatory transcription factor NFκB) and the chemokine monocyte chemoattractant protein-1 (MCP-1/CCL2). Immunohistochemistry confirmed the increased expression of the cellular proteins CD74 and NIK. Paricalcitol (administered in doses of 750 ng/kg of body weight, every other day) had a non-significant impact on neointimal hyperplasia and luminal stenosis. However, it significantly decreased GDF-15, CD74, NIK and MCP-1/CCL2 mRNA expression, which in paricalcitol-injured arteries remained within the levels found in control vehicle sham arteries. In conclusion, paricalcitol had a dramatic effect, suppressing the stress response to guidewire-induced endothelial cell injury, despite a limited impact on neointimal hyperplasia and luminal stenosis. This observation identifies novel molecular targets of paricalcitol in the vascular system, whose differential expression cannot be justified as a consequence of improved tissue injury.

The comparison of paricalcitol and calcitriol effects on pulse wave velocity, osteocalcin, and fetuin-A in chronic hemodialysis patients

INTRODUCTION

Vascular calcification is an intervenable factor in the pathophysiology of cardiovascular disease. Treatment-related factors might worsen the arterial stiffness in chronic hemodialysis patients. The aim of the study is to compare the effects of 1-year treatment with paricalcitol or calcitriol on pulse wave velocity (PWV), which is an indicator of arterial stiffness and osteocalcin and fetuin-A levels.

METHODS

Seventy-six hemodialysis patients who had similar PWV1 at the beginning were evaluated after a 1-year treatment of paricalcitol or calcitriol. PWV2, serum osteocalcin, and fetuin-A levels were measured at the end of the study.

RESULTS

At the end of the study, PWV2 of paricalcitol group was statistically lower than the calcitriol group. Osteocalcin levels were statistically lower and fetuin-A levels were statistically higher in the paricalcitol group than the calcitriol group at the end of the study. The number of patients with PWV2 > 7 m/s and using paricalcitol was 16 (39%) but 25 (41%) patients were using calcitriol; the differences were statistically significant.

CONCLUSIONS

The long-term benefits of paricalcitol were superior to the benefits of calcitriol. Paricalcitol has protective effects from vascular calcification in chronic hemodialysis patients.

Vitamin D and Its Analogues: From Differences in Molecular Mechanisms to Potential Benefits of Adapted Use in the Treatment of Alzheimer’s Disease

Lifestyle habits and insufficient sunlight exposure lead to a high prevalence of vitamin D hypovitaminosis, especially in the elderly. Recent studies suggest that in central Europe more than 50% of people over 60 years are not sufficiently supplied with vitamin D. Since vitamin D hypovitaminosis is associated with many diseases, such as Alzheimer’s disease (AD), vitamin D supplementation seems to be particularly useful for this vulnerable age population. Importantly, in addition to vitamin D, several analogues are known and used for different medical purposes. These vitamin D analogues differ not only in their pharmacokinetics and binding affinity to the vitamin D receptor, but also in their potential side effects. Here, we discuss these aspects, especially those of the commonly used vitamin D analogues alfacalcidol, paricalcitol, doxercalciferol, tacalcitol, calcipotriol, and eldecalcitol. In addition to their pleiotropic effects on mechanisms relevant to AD, potential effects of vitamin D analogues on comorbidities common in the context of geriatric diseases are summarized. AD is defined as a complex neurodegenerative disease of the central nervous system and is commonly represented in the elderly population. It is usually caused by extracellular accumulation of amyloidogenic plaques, consisting of amyloid (Aβ) peptides. Furthermore, the formation of intracellular neurofibrillary tangles involving hyperphosphorylated tau proteins contributes to the pathology of AD. In conclusion, this review emphasizes the importance of an adequate vitamin D supply and discusses the specifics of administering various vitamin D analogues compared with vitamin D in geriatric patients, especially those suffering from AD.

Paricalcitol protects against hydrogen peroxide-induced injury in endothelial cells through suppression of apoptosis

The vascular endothelium is one of the main targets of oxidative stress which plays an important role in the pathophysiology of vascular damage. Recent studies show that vitamin D can positively regulate endothelial functions in various chronic diseases and in cases of increased oxidative stress. In our study, we investigated the restorative and protective potentials of paricalcitol which is frequently used in patients with chronic renal failure, a vitamin D analogue, in human umbilical vein endothelial cells (HUVEC) before and after H₂O₂-induced oxidative stress. Paricalcitol treatment after the oxidative stress induced by H₂O₂ increased cell viability in endothelial cells depending on the dose that was used. While paricalcitol (500 nM) decreased caspase-3 activity and mitochondrial membrane potential loss, it increased nitric oxide (NO) production and reduced glutathione (GSH) levels. Paricalcitol treatment before oxidative stress increased cell viability. It increased NO production and mitochondrial membrane potential while significantly reducing caspase-3 activity. While paricalcitol caused a significant inhibition of protein disulfide isomerase (PDI) reductase activity in healthy endothelial cells, it did not cause a significant change on the PDI reductase activity under oxidative stress conditions. Present study showed that paricalcitol has restorative and protective effects on endothelial cells against oxidative injury, but these effects occur at high concentrations of paricalcitol.

Effect of vitamin D analogues calcitriol and paricalcitol in a rat model of puromycin aminonucleoside-induced nephrotic syndrome

Background Renoprotective effects of vitamin D analogues have been shown in several experimental and clinical studies, the exact mechanism of the therapeutic effectiveness of these analogues in Nephrotic syndrome remains unclear, and these are relatively few studies on potential treatment roles for vitamin D analogues in nephrotic-range proteinuria. ?ndicate similar efficacy of the vitamin D analogues calcitriol and paricalcitol in time-limited amelioration of proteinuria in nephrotic syndrome, yet suggest the likelihood of mechanisms other than direct upregulation of nephrin and podocin in podocytes underlie the renoprotective effects of vitamin D analogues. Objective To investigate the effect of vitamin D (Vit D) analogues calcitriol and paricalcitol on urinary protein/creatinine ratio (UPCR) and renal podocin and nephrin expression in a rat model of puromycin aminonucleoside (PAN)-induced nephrotic syndrome (NS). Methods A total of 28 male Wistar Albino rats were separated into 4 groups (n=7 for each) including CON [control; intraperitoneal (IP) saline injection], PAN (NS + IP saline injection), PAN-C (NS + IP 0.4 µg/kg/day calcitriol injection), and PAN-P (NS + IP 240 ng/kg/day paricalcitol injection). Nephrotic syndrome was induced via intravenous (IV) administration of 10mg/100gr PAN. The UPCR as well as histopathological, immuno-histochemical, and real time PCR analyses of kidney tissue specimens were recorded and analyzed among the 4 groups. Results Median UPCR (Day 4) was significantly lower in both the PAN-C [1.45 (range 1.20-1.80)] and PAN-P [1.40 (range 1.10-1.80)] groups than in the PAN group [2.15 (range 2.00-2.40)] (P<0.01 for each). The PAN group had significantly higher mean UPCR than the CON group [1.75 (range 1.40-2.00); P<0.05].  No significant difference in UPCR was noted between groups on Day 7. Median podocin mRNA expression was significantly higher in the PAN-P group compared to the PAN group [22.55 (range 22.42-23.02) vs. 22.06 (range 21.81-22.06), respectively; (P<0.01)]. Conclusion Seven-day calcitriol and paricalcitol supplementation in a rat model of PAN-induced nephrotic syndrome had similar efficacy, in terms of temporary amelioration of proteinuria.

New Insights into Vitamin K-From Its Natural Sources through Biological Properties and Chemical Methods of Quantitative Determination

Vitamin K is one of the many health-promoting substances whose impact on the human body has been underestimated until recently. However, recently published research results have changed this situation, prompting some researchers to consider it a new panacea for diseases of old age. The result is a significant increase in interest in the accurate analysis of vitamin K in various types of samples, ranging from food, through dietary supplements, to biological matrices and clinical trials, both observational and interventional. This review summarizes the current state of knowledge about the proven and speculated biological activity of vitamin K and its importance for the world's aging societies, including the methods used for its isolation and analysis in various matrices types. Of all the analytical methods, the currently preferred methods of choice for the direct analysis of vitamin K are chromatographic methods, in particular liquid chromatography-tandem mass spectrometry. This technique, despite its sensitivity and selectivity, requires an appropriate stage of sample preparation. As there is still room for improvement in the efficiency of these methods, especially at the sample preparation stage, this review shows the directions that need to be taken to make these methods faster, more efficient and more environmentally friendly.

The American Association of Endocrine Surgeons Guidelines for the Definitive Surgical Management of Secondary and Tertiary Renal Hyperparathyroidism

OBJECTIVE

To develop evidence-based recommendations for safe, effective, and appropriate treatment of secondary (SHPT) and tertiary (THPT) renal hyperparathyroidism.

BACKGROUND

Hyperparathyroidism is common among patients with chronic kidney disease, end-stage kidney disease, and kidney transplant. The surgical management of SHPT and THPT is nuanced and requires a multidisciplinary approach. There are currently no clinical practice guidelines that address the surgical treatment of SHPT and THPT.

METHODS

Medical literature was reviewed from January 1, 1985 to present January 1, 2021 by a panel of 10 experts in SHPT and THPT. Recommendations using the best available evidence was constructed. The American College of Physicians grading system was used to determine levels of evidence. Recommendations were discussed to consensus. The American Association of Endocrine Surgeons membership reviewed and commented on preliminary drafts of the content.

RESULTS

These clinical guidelines present the epidemiology and pathophysiology of SHPT and THPT and provide recommendations for work-up and management of SHPT and THPT for all involved clinicians. It outlines the preoperative, intraoperative, and postoperative management of SHPT and THPT, as well as related definitions, operative techniques, morbidity, and outcomes. Specific topics include Pathogenesis and Epidemiology, Initial Evaluation, Imaging, Preoperative and Perioperative Care, Surgical Planning and Parathyroidectomy, Adjuncts and Approaches, Outcomes, and Reoperation.

CONCLUSIONS

Evidence-based guidelines were created to assist clinicians in the optimal management of secondary and tertiary renal hyperparathyroidism.

The efficacy and safety of cinacalcet in primary hyperparathyroidism: a systematic review and meta-analysis of randomized controlled trials and cohort studies

Cinacalcet, a positive allosteric modulator of the calcium sensing receptor (CaSR) reduces parathyroid hormone (PTH) secretion by increasing the sensitivity of the CaSR on parathyroid cells. We conducted a systematic review and meta-analysis on the safety and efficacy of cinacalcet in Primary Hyperparathyroidism (PHPT). MEDLINE, Embase, BIOSIS, and the Cochrane Library were searched for published articles (from database inception to Sept 2020). All double-blind RCTs and cohort studies that reported data on the efficacy and safety of cinacalcet therapy in individuals ≥ 18 with PHPT were included. Random effect meta-analysis was performed to estimate the efficacy of cinacalcet in lowering serum calcium and PTH levels compared with placebo. 4 RCTs (177 participants) and 17 cohort studies (763 participants) were eligible for final analysis. Pooled results from the RCTs suggest that, when compared to placebo and administered for up to 28 weeks, cinacalcet normalizes serum calcium (≤ 10.3 mg/dl) in patients with PHPT [RR 20 (95% CI 6.04 - 68.52, I² = 0%, p_{heterogeneity} < 0·00001)]. Serum PTH levels decreased significantly after 2 weeks and up to 28 weeks after treatment with cinacalcet. In the pooled analysis of the 17 cohort studies, serum calcium levels normalized in 76% (95% CI 66% to 86%; I² = 92%, p_{heterogeneity} < 0·00001) of patients regardless of the duration of treatment. In most studies, PTH levels decreased by 13% to 55%. No RCT reported on BMD as a primary or secondary outcome, and no improvement in BMD was noted in the 2 non-randomized studies that reported densitometric findings. No significant difference in urinary calcium was noted with cinacalcet therapy in either the RCTs or non-randomized studies. There was no significant difference in overall adverse events (AE) (RD 0.01, 95% CI -0.07 to 0.26) compared to placebo noted in the RCTs. In the non-randomized studies, pooled weighted AE rate was 45% (95% CI 32 to 59%). Risk of bias was low in 2/4 RCTs and 6/17cohort studies; risk was intermediate in 2/4 RCTs and 8/17 cohort studies, and risk was high in 3/17 cohort studies. In PHPT, cinacalcet lowers serum calcium and PTH with greater effects on calcium than on PTH in the short term. In the doses reported, the drug is safe with tolerable side effects. These findings can help inform targeted medical therapy of PHPT in those for whom lowering the serum calcium is indicated and for whom parathyroidectomy is not an option.

Paricalcitol versus Calcitriol + Cinacalcet for the Treatment of Secondary Hyperparathyroidism in Chronic Kidney Disease in China: A Cost-Effectiveness Analysis

Background: Chronic Kidney Disease (CKD) is a global chronic disease with increasing prevalence in recent years, particularly CKD accompanied by Secondary Hyperparathyroidism (SHPT) leads to reduced quality of life, increased mortality, a considerable economic burden for patients and society. The aim of this study was to investigate the cost-effectiveness analysis of paricalcitol vs. calcitriol + cinacalcet for CKD patients with SHPT in China in 2020.

Methods: A Markov model was conducted employing data derived from published literature, clinical trials, official sources, and tertiary public hospital data in China, based on a 10-year horizon from the perspective of the healthcare system. Calcitriol + Cinacalcet was used as the reference group. CKD stage 5 (CKD-5) dialysis patients suffering from SHPT were included in the study. Effectiveness was measured in quality-adjusted life years (QALYs). The discount rate (5%) was applied to costs and effectiveness. Sensitivity analysis was performed to confirm the robustness of the findings.

Results: The base case analysis demonstrated that Patients treated with paricalcitol could gain an increase in utility (0.183 QALYs) and require fewer expenditures (6925.612 yuan). One-way sensitivity analysis was performed to showed that impact factors were the price of cinacalcet, the hospitalization costs of patients with paricalcitol and calcitriol, the costs and utilities of hemodialysis and the costs of calcitriol, the costs of paricalcitol regardless of period. Probabilistic simulation analysis displayed when willingness-to-pay was ¥217113, the probability that Paricalcitol was dominant is 96.20%.

Conclusion: The results showed that paricalcitol administrated to treat patients diagnosed with Secondary hyperparathyroidism in Chronic Kidney Disease, compared to calcitriol and cinacalcet, might be dominant in China.

Effects of high- vs low-dose native vitamin D on albuminuria and the renin-angiotensin-aldosterone system: a randomized pilot study

BACKGROUND

Residual albuminuria is associated with an increased risk of progression to ESKD. We tested whether a supplementation with native vitamin D could reduce albuminuria in stable CKD patients under maximal renin-angiotensin system (RAS) blockade.

METHODS

We conducted a randomized controlled study of high (cholecalciferol 100 000 UI per 10 days over 1 month) vs low-dose (ergocalciferol 400 UI/days over 1 month) supplementation with native vitamin D on urinary albumin/creatinine ratio, blood pressure and the RAS over 1 month in stable CKD patients with albuminuria and maximum tolerated RAS blockade.

RESULTS

We included 31 patients, 21 in the high dose group and 10 in the low dose group. In contrast with a low dose, high dose vitamin D normalized plasma 25(OH)D, decreased iPTH but slightly increased plasma phosphate. High dose vitamin D decreased geometric mean UACR from 99.8 mg/mmol (CI 95% 60.4-165.1) to 84.7 mg/mmol (CI 95% 51.7-138.8, p = 0.046). In the low dose group, the change in geometric mean UACR was not significant. Blood pressure, urinary 24 h aldosterone and peaks and AUC of active renin concentrations after acute stimulation by a single dose of 100 mg captopril were unaffected by the supplementation in native vitamin D, irrespective of the dose. Native vitamin D supplementation was well tolerated.

CONCLUSIONS

We found a small (- 15%) but significant decrease in albuminuria after high dose vitamin D supplementation. We found no effect of vitamin D repletion on blood pressure and the systemic RAS, concordant with recent clinical studies.

Signaling Pathways Involved in Diabetic Renal Fibrosis

Diabetic kidney disease (DKD), as the most common complication of diabetes mellitus (DM), is the major cause of end-stage renal disease (ESRD). Renal interstitial fibrosis is a crucial metabolic change in the late stage of DKD, which is always considered to be complex and irreversible. In this review, we discuss the pathological mechanisms of diabetic renal fibrosis and discussed some signaling pathways that are closely related to it, such as the TGF-β, MAPK, Wnt/β-catenin, PI3K/Akt, JAK/STAT, and Notch pathways. The cross-talks among these pathways were then discussed to elucidate the complicated cascade behind the tubulointerstitial fibrosis. Finally, we summarized the new drugs with potential therapeutic effects on renal fibrosis and listed related clinical trials. The purpose of this review is to elucidate the mechanisms and related pathways of renal fibrosis in DKD and to provide novel therapeutic intervention insights for clinical research to delay the progression of renal fibrosis.

Neuroprotective effect of paricalcitol in a rat model of transient global cerebral ischemia

Background

Paricalcitol is known to attenuate ischemic-reperfusion injury of various organs. However, it is not known whether paricalcitol prevents neuronal injury after global cerebral ischemia. The purpose of this study is to investigate the neuroprotective effect of paricalcitol in a rat model of transient global cerebral ischemia.

Methods

This is a prospective, randomized experimental study. Male Sprague-Dawley rats that survived 10 min of four-vessel occlusion were randomly assigned to two treatment groups: one group was treated with paricalcitol 1 μg/kg IP, and the other was given an equivalent volume of normal saline IP. Drugs were administered at 5 min, 1 day, 2 days, and 3 days after ischemia. Neurologic function was assessed at 2 h, 1 day, 2 days, 3 days, and 4 days after ischemia. We tested motor function 3 days after ischemia using the rotarod test. Also, we tested memory function 4 days after ischemia using the passive avoidance test. We assessed neuronal degeneration in the hippocampus of surviving rats 4 days after ischemia.

Results

Eight rats were allocated to each group. No significant differences were found between the groups in terms of survival rate, motor coordination, or memory function. The neurological function score 2-h post-ischemia was significantly higher in the paricalcitol group (p = 0.04). Neuronal degeneration was significantly less in the paricalcitol group compared with the control group (p = 0.01).

Conclusions

Paricalcitol significantly attenuated neuronal injury in the hippocampus. Although motor coordination, memory function, and survival rate were not significantly improved by paricalcitol treatment in this study, paricalcitol remains a potential neuroprotective drug after global cerebral ischemia.

A comparative analysis of the efficacy and safety of paricalcitol versus other vitamin D receptor activators in patients undergoing hemodialysis: A systematic review and meta-analysis of 15 randomized controlled trials

Paricalcitol, a new vitamin D receptor activator (VDRA), is reported to be more effective than other VDRAs in reducing calcium and phosphorus levels in patients undergoing hemodialysis. However, the efficacy and safety of paricalcitol remain controversial. This analysis compares paricalcitol with other VDRAs in patients undergoing hemodialysis. We searched the Cochrane Library, PubMed, EMBASE, Web of Science, and CNKI up to April 22, 2019. Standardized mean difference (SMD), risk ratio (RR) and 95% confidence interval (CI) values were estimated to compare the outcomes of the groups. Two reviewers extracted data and assessed trial quality independently. All statistical analyses were performed using the standard statistical procedures of RevMan 5.2 and Stata 12.0. Fifteen studies (N = 110,544) were included in this meta-analysis. Of these studies, 11 were randomized controlled trials (RCTs) and 4 were non-randomized studies of interventions (NRSIs). Patients receiving paricalcitol experienced better overall survival (OS) than patients receiving other VDRAs, with a pooled hazard ratio of 0.86 (95% CI 0.80–0.91; P < 0.00001). Intact parathyroid hormone (iPTH) levels were significantly reduced in the paricalcitol group compared to the group receiving other VDRAs, with a pooled SMD of -0.53 (95% CI -0.89– -0.16; P = 0.004). There was a significant increase in serum calcium levels from baseline in the paricalcitol group compared to the other VDRAs group when limiting the analysis to RCTs, with a pooled SMD of 2.14 (95% CI 0.90–3.38; P = 0.0007). Changes in serum calcium levels were significantly lower in the paricalcitol group when the analysis was limited to NRSIs, with a pooled SMD of -0.85 (95% CI -1.34–-0.35; P = 0.0008). The NSRI analysis also showed a significant reduction in serum phosphorus levels in the paricalcitol group, with a pooled SMD of -0.57 (95% CI -1.00–-0.13; P = 0.01). No significant differences were observed in the incidence of hypercalcemia, hyperphosphatemia, or adverse events. Generally, paricalcitol seems superior to other VDRAs in reducing mortality and iPTH levels in patients undergoing hemodialysis. However, the comparative effectiveness of paricalcitol in reducing serum calcium and phosphorus levels needs further exploration. No significant difference was found in the rate of adverse events.

Relation Between Crystal Structures of Precursors and Final Products: Example of Vitamin D Intermediates

In this paper, we proved that the solid-state structure of vitamin D analog is well represented by the structures of its structural fragments. This is important in predicting the biological activity of vitamin D analogs that are not available in the solid form. The previously published crystal structure of advanced vitamin D intermediate provided additional insights into vitamin D properties. A similar analysis based on simple vitamin D intermediate analogues showed that precursors crystallized in the space groups typical for vitamins D; geometrical parameters were related to the corresponding parameters in the vitamin D analogues; and crystal structures of the basic intermediates and their final products contained similar intermolecular interactions, essential for the infinite hydrogen bond motif observed in the vitamin D analogues. The energy of these interactions is related as shown by theoretical calculations, that is, energy frameworks analysis. Moreover, analysis of the hydrogen bonds motifs revealed a relation between these motifs and the absolute configuration of basic intermediates as well as the space orientation of the exocyclic methylene group in the final structures.

The effect of vitamin D3 and paricalcitol on penicillin-induced epileptiform activity in rats

AIM

Epilepsy is a disease characterized by seizures which impair human life considerably. Vitamin D is of different systemic effects on metabolism and its deficiency is known to have a high prevalence among epilepsy patients. Paricalcitol, a vitamin D receptor agonist, has relatively fewer side effects. This study aimed to investigate the anticonvulsant effect of vitamin D₃ (cholecalciferol) and paricalcitol on penicillin-induced epileptiform activity.

METHOD

21 male Wistar rat weighing 180-240 g were used. After anesthetized by 1.25 g/kg urethane intraperitoneally (i.p.), rats were placed in the stereotaxic frame and tripolar electrodes were placed on the skull. The single microinjection of penicillin (2.5 μl, 500 IU, i.c.) into left sensorimotor cortex induced epileptiform activity. A single dose of 60.000 IU/kg (i.p.) vitamin D₃ was administered 14 days before intracortical penicillin (500 IU) injection. Paricalcitol (10 μg/kg, i.p.) was administered 30 min before intracortical penicillin (500 IU) administration and recorded for the following 180 min.

RESULTS

Vitamin D₃ pretreatment and paricalcitol diminished the frequency of epileptiform activity (p < 0.001) without changing the amplitude (p > 0.05) compared to the penicillin-injected group. Vitamin D₃ pretreatment and paricalcitol led to an important delay in the onset of penicillin-induced epileptiform activity (p < 0.001 and p < 0.05, respectively). Vitamin D₃ increased the latency of penicillin-induced epileptic activity compared to paricalcitol group (p < 0.001).

CONCLUSION

Results indicate that vitamin D₃ and paricalcitol decreased the frequency and increased the latency of the penicillin-induced epileptic activity. Vitamin D₃ was more effective than paricalcitol.

Antifibrotic effects of hypocalcemic vitamin D analogs in murine and human hepatic stellate cells and in the CCl4 mouse model

Liver cirrhosis is a life-threatening consequence of liver fibrosis. The aim of this study was to investigate the antifibrotic potential of clinically available vitamin D analogs compared to that of calcitriol in vitro and in vivo. Murine hepatic stellate cells, Kupffer cells, and human LX-2 cells were treated with vitamin D analogs, and the profibrotic behavior of these cells was studied. In vivo liver fibrosis was induced using CCl₄ until measurable fibrosis was established. Animals were then treated with calcitriol and paricalcitol. Vitamin D and its analogs showed antifibrotic effects in vitro. Treatment with active vitamin D (calcitriol, CAL) and its analogs reduced the protein expression of α-smooth muscle actin (α-SMA) in mHSC. In human LX-2 cells alfacalcidol reduced transforming growth factor-β (TGF-β) induced platelet-derived growth factor receptor-β protein expression and contractility while paricalcitol (PCT), in its equipotent dose to CAL, reduced TGF-β induced α-SMA protein expression, and ACTA2 and TGF-β mRNA expression. No effects of a treatment with vitamin D and its analogs were observed in Kupffer cells. In vivo, PCT-treated mice had significantly lower calcium levels than CAL-treated mice. CAL and PCT reduced the hepatic infiltration of CD11b-positive cells and alanine transaminase levels, while PCT but not CAL significantly inhibited fibrosis progression, with a favorable side effect profile in the CCl₄ model. We conclude that hypocalcemic vitamin D analogs should be considered in future studies investigating vitamin D for the treatment of liver fibrosis.

Considerations and controversies in managing chronic kidney disease: An update

PURPOSE

Current considerations and controversies surrounding the management of chronic kidney disease (CKD) are reviewed.

SUMMARY

Patients diagnosed with CKD require a unique clinical approach to prevent medication toxicities and ensure appropriate management of disease-progressing comorbidities, and they require attention to commonly occurring complications that may affect disease control and impact quality of life, including anemia and CKD-bone-mineral disorder (CKD-BMD). Many CKD-related comorbidities put patients at increased cardiovascular risk, including diabetes, hypertension, and hyperlipidemia. Although there are clinical guidelines to help clinicians manage CKD and its related complications and comorbidities, there are many clinical controversies surrounding optimal treatment. Recent literature and clinical studies bring into question multiple controversies regarding the optimal management approach to the patient living with CKD, including the appropriateness of iron and erythropoiesis-stimulating agents (ESAs) for the treatment of anemia and vitamin D supplementation for the prevention of CKD-BMD. While available guidelines can provide clinicians with guidance regarding the appropriate management of the patient with CKD, they often differ dramatically in the optimal approach to the management of comorbidities and complications. For a patient with CKD, the pharmacist has an important role to ensure optimal outcomes, by appropriately managing comorbid conditions and optimizing drug dosing.

CONCLUSION

Multiple controversies regarding the optimal management of patients with CKD, including the appropriateness of iron and ESAs for treatment of anemia and vitamin D supplementation for the prevention of CKD-BMD. Available guidelines differ dramatically in the optimal approach to the management of comorbidities and complications.

Active Vitamin D in Chronic Kidney Disease: Getting Right Back Where We Started from?

BACKGROUND

The vitamin D system is essential for optimal health in humans. Circulating calcitriol, a key metabolite in maintaining calcium and phosphorus homeostasis, is produced in the kidney. In kidney failure, calcitriol levels progressively decrease, contributing to the development of renal secondary hyperparathyroidism (SHPT).

SUMMARY

For years, SHPT had a central role in the disturbed mineral metabolism of renal patients. As calcitriol deficiency contributes to SHPT development, treatment with calcitriol or other compounds able to activate the vitamin D receptor (VDR) was one of the mainstays of therapy for renal patients in the last 40 years. In this review, we discuss how the treatment with VDR activators (VDRA) evolved during this time in the United States, as well as the main factors responsible for these changes.

KEY MESSAGES

Management of SHPT with VDRA in renal patients has undergone a few paradigm shifts over the last 40 years. When treating SHPT, the newly developed therapies as well as VDRA need to be carefully considered and used appropriately. Nephrologists need to use an integrated approach that avoids excessive use of VDRA, ensures replenishment of vitamin D stores, and avoids hypercalcemia and hyperphosphatemia.

Mineral bone disorders in chronic kidney disease

As the GFR loss aggravates, the disturbed mineral metabolism worsens the bone microstructure and remodelling - scenario, which is known as CKD-mineral bone disease (MBD). CKD-MBD is characterized by : (i) abnormal metabolism of calcium, phosphorus, parathyroid hormone (PTH), or vitamin D; (ii) abnormalities in bone turnover, mineralization, volume linear growth or strength; (iii) soft-tissue calcifications, either vascular or extra-osseous. Uremic vascular calcification and osteoporosis are the most common complications related to CKD-MBD. Disregulated bone turnover by uremic toxin or secondary hyperparathyroidism disturbed bone mineralization and makes it difficult for calcium and inorganic phosphate to enter into bone, resulting in increased serum calcium and inorganic phosphate. Vascular calcification worsens by hyperphosphatemia and systemic inflammation. Since vitamin D deficiency plays an important role in renal osteodystrophy, supplement of nutritional vitamin D is important in treating uremic osteoporosis and vascular calcification at the same time. Its pleotropic effect improves the bone remodeling initiated by osteoblast and alleviates the risk factors for vascular calcification with less hypercalcemia than vitamin D receptor analogs. Therefore, nutritional vitamin D should be considered in managing CKDMBD.

Secondary Hyperparathyroidism: Pathogenesis and Latest Treatment

The classic pathogenesis of secondary hyperparathyroidism (SHPT) began with the trade-off hypothesis based on parathyroid hormone hypersecretion brought about by renal failure resulting from a physiological response to correct metabolic disorder of calcium, phosphorus, and vitamin D. In dialysis patients with failed renal function, physiological mineral balance control by parathyroid hormone through the kidney fails and hyperparathyroidism progresses. In this process, many significant genetic findings have been established. Abnormalities of Ca-sensing receptor and vitamin D receptor are associated with the pathogenesis of SHPT, and fibroblast growth factor 23 has also been shown to be involved in the pathogenesis. Vitamin D receptor activators (VDRAs) are widely used for treatment of SHPT. However, VDRAs have calcemic and phosphatemic effects that limit their use to a subset of patients, and calcimimetics have been developed as alternative drugs for SHPT. Hyperphosphatemia also affects progression of SHPT, and control of hyperphosphatemia is, therefore, thought to be fundamental for control of SHPT. Currently, a combination of a VDRA and a calcimimetic is recognized as the optimal strategy for SHPT, and for other outcomes such as reduced cardiovascular disease and improved survival. The latest findings on the pathogenesis and treatment of SHPT are summarized in this review.

Updates in CKD-Associated Osteoporosis

PURPOSE OF REVIEW

Chronic kidney disease (CKD) is associated with bone loss and fractures. The purpose of this review is to provide clinicians with an overview of the underlying pathogenesis of CKD-associated osteoporosis, and a summary of the current diagnostic and therapeutic approaches to this disease.

RECENT FINDINGS

In 2017, the Kidney Disease Improving Global Outcomes Committee on Bone Quality updated their guidelines to include screening for osteoporosis and fracture risk by dual energy X-ray absorptiometry in patients with CKD. Once a diagnosis of osteoporosis and/or fracture risk is established, it is not clear how nephrologists should manage their patients. Patients with CKD should be screened for CKD-associated osteoporosis and considered for strategies that prevent bone loss and fractures. Assessment of bone turnover via imaging, biochemical testing, or bone biopsy can help guide the choice of therapy. Randomized controlled trials are needed to assess safety and efficacy of treatments to prevent bone loss and fractures.

A Bayesian network analysis on comparative efficacy of treatment strategies for dialysis patients with secondary hyperparathyroidism

For dialysis patients with end-stage kidney disease and secondary hyperparathyroidism (SHPT), there are three therapeutic treatment options: Cinacalcet, paricalcitol and cinacalcet plus low-dose vitamin D analogues. However, their comparative efficacy remains unclear at present. Thus, in the current study, a Bayesian network analysis was conducted to evaluate the relative efficacy and safety of these three therapeutic regimens. A comprehensive literature database query was performed. The primary outcome was the treatment effect on serum parathyroid hormone (PTH) levels. Secondary outcomes included the occurrence of nausea and hypocalcaemia. A total of 20 randomized clinical trials, including 5,390 dialysis patients, were entered into the analysis. Paricalcitol, cinacalcet plus vitamin D analogue and cinacalcet were significantly more efficacious in controlling PTH levels compared with conventional therapy (which comprises calcium-based phosphate binders, non-calcium-based phosphate binders and vitamin D analogues) [odds ratio (OR)=3.99, 2.91 and 2.47, respectively] and placebo (OR=20.32, 14.89 and 12.56, respectively). Paricalcitol was identified as the most efficacious of the three treatments. According to a ranking analysis, patients treated with cinacalcet had a higher possibility of frequently developing nausea and hypocalcaemia compared with patients treated with cinacalcet plus low-dose active vitamin D analogues. All three therapeutic treatment options were efficacious for the treatment of dialysis patients with SHPT in controlling PTH levels. Paricalcitol had the highest possibility of being the most optimal one. Thus, paricalcitol therapy may be the most optimal regimen in controlling PTH levels, but this should be confirmed by further study.

Comparison of Paricalcitol and Calcitriol in Dialysis Patients With Secondary Hyperparathyroidism: A Meta-Analysis of Randomized Controlled Studies

Paricalcitol and calcitriol are widely used for the treatment of secondary hyperparathyroidism in dialysis patients. We conducted a systematic review and meta-analysis to compare the efficacy and safety of paricalcitol and calcitriol for secondary hyperparathyroidism in dialysis patients. PubMed, EMbase, Web of Science, EBSCO, and Cochrane library databases were systematically searched. Randomized controlled trials (RCT) assessing the efficacy of paricalcitol and calcitriol for secondary hyperparathyroidism in dialysis patients are included. Two investigators independently searched articles, extracted data, and assessed the quality of included studies. Meta-analysis was carried out using the random-effect model. Six randomized controlled trials are included in the meta-analysis. Overall, compared with calcitriol treatment for secondary hyperparathyroidism in dialysis patients, paricalcitol treatment has comparable ≥50% reduction of parathyroid hormone (risk ratio [RR] = 1.33; 95% CI = 0.93-1.91; P = 0.12), calcium concentration (standard mean difference [Std. MD] = -0.21; 95% CI = -0.94 to 0.52; P = 0.58), phosphate concentration (Std. MD = -0.17; 95% CI = -0.58 to 0.24; P = 0.42), calcium phosphate (Std. MD = -0.08; 95% CI = -0.49-0.34; P = 0.71), alkaline phosphatase (Std. MD = -0.21; 95% CI = -0.73-0.31; P = 0.43), hypercalcemia (RR = 1.43; 95% CI = 0.51 to 3.98; P = 0.49), adverse events (RR = 0.79; 95% CI = 0.42-1.49; P = 0.47), and serious adverse events (RR = 0.78; 95% CI = 0.47-1.30; P = 0.33). Paricalcitol and calcitriol result in similar ≥50% reduction of parathyroid hormone, calcium concentration, phosphate concentration, calcium phosphate, alkaline phosphatase, hypercalcemia, adverse events, and serious adverse events for secondary hyperparathyroidism in dialysis patients.

A phase 1, open-label, dose escalation study of intravenous paricalcitol in combination with gemcitabine in patients with advanced malignancies

BACKGROUND

Calcitriol, the active analogue of vitamin D, is antiproliferative and enhances the cytotoxicity of several anticancer agents, including gemcitabine. The vitamin D receptor (VDR) is expressed in the tumor stroma and treatment with VDR ligands results in stromal remodeling and increased intratumoral gemcitabine delivery. Furthermore, calcitriol can decrease the activity of the gemcitabine deactivating enzyme cytidine deaminase (CDD). Because hypercalcemia has been the most worrisome calcitriol-related adverse event, the less hypercalcemic agent paricalcitol may be preferred for further investigation.

METHODS

The authors undertook a phase 1 study of gemcitabine in combination with escalating doses of paricalcitol administered weekly intravenously in patients with advanced cancers. A standard 3+3 dose escalation schema was used. Pharmacokinetic assessment of gemcitabine and its metabolite 2',2'-difluorodeoxyuridine (dFdU) was performed. Pharmacodynamic assessment of paricalcitol was performed by measurement of CDD activity in peripheral blood mononuclear cells.

RESULTS

A total of 44 patients were enrolled. Somnolence was the main dose-limiting toxicity. The highest dose of paricalcitol administered was 10.5 µg/kg. Hypercalcemia was infrequent and mild in severity. Paricalcitol did not appear to affect the pharmacokinetics of gemcitabine and dFdU. Evaluation of CDD activity was available for 9 patients; no clear trend for CDD activity after treatment with paricalcitol was established. The overall response rate was 4%; the rate of disease control was 67% in patients who were pretreated with gemcitabine. Progression-free and overall survival were 3.4 months and 6.5 months, respectively.

CONCLUSIONS

Paricalcitol can be administered safely in doses up to 7 µg/kg weekly with fixed dose rate gemcitabine without dose-limiting hypercalcemia. To the best of the authors' knowledge, the maximum tolerated dose has not been formally established to date. Preliminary clinical activity deserves further exploration.

Evidence-based complementary treatment of pancreatic cancer: a review of adjunct therapies including paricalcitol, hydroxychloroquine, intravenous vitamin C, statins, metformin, curcumin, and aspirin

Despite new and exciting research and renewed optimism about future therapy, current statistics of survival from pancreatic cancer remains dismal. Patients seeking alternative or complementary treatments should be warned to avoid the hype and instead look to real science. A variety of relatively safe and inexpensive treatment options that have shown success in preclinical models and/or retrospective studies are currently available. Patients require their physicians to provide therapeutic guidance and assistance in obtaining and administrating these various therapies. Paricalcitol, an analog of vitamin D, has been shown by researchers at the Salk Institute for Biological Studies to break though the protective stroma surrounding tumor cells. Hydroxychloroquine has been shown to inhibit autophagy, a process by which dying cells recycle injured organelles and internal toxins to generate needed energy for survival and reproduction. Intravenous vitamin C creates a toxic accumulation of hydrogen peroxide within cancer cells, hastening their death. Metformin inhibits mitochondrial oxidative metabolism utilized by cancer stem cells. Statins inhibit not only cholesterol but also other factors in the same pathway that affect cancer cell growth, protein synthesis, and cell cycle progression. A novel formulation of curcumin may prevent resistance to chemotherapy and inhibit pancreatic cancer cell proliferation. Aspirin therapy has been shown to prevent pancreatic cancer and may be useful to prevent recurrence. These therapies are all currently available and are reviewed in this paper with emphasis on the most recent laboratory research and clinical studies.

Evidence basis for integrated management of mineral metabolism in patients with end-stage renal disease

PURPOSE OF REVIEW

Treatment of mineral metabolism is a mainstay of dialysis care including some of its most widely used and costly pharmaceuticals. Although many mineral metabolites are associated with increased risk of mortality, cardiovascular disease, and other morbidities, few clinical trials are available to guide therapy and most focus on single drug approaches. In practice, providers manage many aspects of mineral metabolism simultaneously in integrated treatment approaches that incorporate multiple agents and changes in the dialysis prescription. The present review discusses the rationale and existing evidence for evaluating integrated, as opposed to single drug, approaches in mineral metabolism.

RECENT FINDINGS

Drugs used to treat mineral metabolism have numerous, and sometimes, opposing effects on biochemical risk factors, such as fibroblast growth factor 23 (FGF23), calcium, and phosphorus. Although vitamin D sterols raise these risk markers when lowering parathyroid hormone (PTH), calcimimetics lower them. Trials demonstrate that combined approaches best 'normalize' the mineral metabolism axis in end-stage renal disease (ESRD). Observations embedded within major trials of calcimimetics reveal that adjustment of calcium-based binders and dialysate calcium is a common approach to adverse effects of these drugs with some initial, but inconclusive, evidence that these co-interventions may impact outcomes.

SUMMARY

The multiple, and often opposing, biochemical effects of many mineral metabolism drugs provides a strong rationale for studying integrated management strategies that consider combinations of drugs and co-interventions as a whole. This remains a current gap in the field with opportunities for clinical trials.

Pharmacokinetics of a New Oral Vitamin D Receptor Activator (2-Methylene-19-Nor-(20S)-1α,25-Dihydroxyvitamin D3) in Patients with Chronic Kidney Disease and Secondary Hyperparathyroidism on Hemodialysis

Background

2-Methylene-19-nor-(20S)-1α,25-dihydroxyvitamin D₃ (DP001 or 2MD) is a novel, potent 1α-hydroxylated vitamin D analog that binds to the vitamin D receptor and suppresses parathyroid hormone synthesis and secretion with potential for an improved safety profile compared to existing active vitamin D analogs. The purpose of this study was to evaluate the pharmacokinetics of DP001 given orally after hemodialysis.

Methods

DP001 (550 ng) was given orally to 11 hemodialysis patients with secondary hyperparathyroidism after each dialysis session (3 times/week) for 4 weeks. Pharmacokinetic analyses were performed after the first and final dose.

Results

After the first and final dose, the half-life of DP001 was similar (55.8 ± 13.0 and 50.8 ± 8.2 h, respectively). At 4 weeks, the time to maximum plasma concentration was 4.0 ± 0.8 h, with a concentration maximum of 3.4 ± 0.3 pg/mL. The area under the curve (0 to infinity) after the final dose was 204.3 ± 23.9 pg h/mL, and apparent volume of distribution was 2.03 ± 0.22 L/kg. At week 4, mean intact parathyroid hormone was suppressed 33% from the baseline (pre-dose) value (313 ± 52 vs 462 ± 39 pg/mL, respectively). No clinically significant changes from baseline values were found for vital signs, electrocardiogram measurements, or other laboratory parameters, including serum calcium and phosphorus.

Conclusions

In hemodialysis patients, DP001 has a longer half-life than existing vitamin D therapies and enables control of parathyroid hormone when administered every 2–3 days on the day of dialysis. It is effective at a lower concentration maximum and area under the curve than other clinically available vitamin D compounds. DP001 may represent a therapeutic improvement over existing compounds due to rapid and extensive distribution to its target and its long half-life enabling sustained parathyroid hormone suppression. These studies support further evaluation of DP001 in longer-term treatment of secondary hyperparathyroidism.

Paricalcitol and Peritoneal Protein Loss in Peritoneal Dialysis: A Double-Center Study

BACKGROUND/AIMS

Peritoneal protein loss (PPL) is associated with cardiovascular disease and mortality in peritoneal dialysis (PD). Controversial results have been published about the effect of paricalcitol in PPL among PD patients. This study intends to analyze the relationship between paricalcitol and PPL in PD.

METHODS

In a retrospective study, prevalent PD patients were divided into 2 groups: "with paricalcitol" and "without paricalcitol". X2-test, Student's t test, Pearson correlation coefficient and Logistic Regression analysis were applied.

RESULTS

Eighty-two patients were included. PPL was lower among patients medicated with paricalcitol (5.17 ± 1.71 vs. 6.79 ± 2.10 g/24 h, p = 0.0001). In multivariate analysis, paricalcitol and dialysate/plasma ratio of creatinine (D/P creatinine) were independently related to PPL (OR 4.270 [1.437-12.684], p = 0.009 and OR 0.205 [0.064-0.659], p = 0.008, respectively), adjusted for diabetes.

CONCLUSION

Paricalcitol and D/P creatinine were independently related to PPL. Paricalcitol may have an effect on PPL in PD patients.

[Utilization of alfacalcidol and active vitamin D analogs in chronic kidney disease]

Secondary hyperparathyroidism (SHPT) is one of the most frequent and deleterious complication of chronic kidney disease (CKD). SHPT is also one of the principal components of the now called CKD-mineral and bone disorders (MBD) syndrome. It is usually prevented and treated by vitamin D derivatives. However, the rationale for the prescription of vitamin D sterols in those patients is still a matter of hotly debates, mainly because of unsatisfactory results from numerous observational and not well-controlled studies. Scanty clinical data on head-to-head comparisons between the multiple vitamin D sterols are currently available. Moreover, there is crescent expectations on nutritional vitamin D, as well as vitamin D receptor activators (VDRA), regarding their putative pleiotropic effects even in CKD patients, and the promising effects of VDRA against proteinuria and myocardial hypertrophy in diabetic CKD cohorts. Nevertheless, additional randomized controlled trials (RCT) are needed to answer to many open questions and incertitude considering the effect of nutritional vitamin D and VDRA on hard end points including the risk of skeletal fractures and of mortality in CKD patients. RCT comparing VDRA to calcimimetics in the control of SHPT are also needed in dialysis patients. The present review will visit these open questions that nephrologists should ask before starting a treatment by nutritional vitamin D or VDRA.

Vitamin D Receptor Activators

The fields for clinical employment of vitamin D analogs are growing and under active evaluation in different medical specialties, ranging from dermatology to immunology and oncology. In this review we provide a brief description of the drugs that have been developed more specifically for the treatment of secondary hyperparathyroidism (SH) associated with uremia.

Effects of oral paricalcitol therapy on arterial stiffness and osteopontin in hypertensive patients with chronic kidney disease and secondary hyperparathyroidism

BACKGROUND

Arterial stiffness is linked to the progression of atherosclerosis, while activation of vitamin D receptor exerts favorable cardiovascular effects in patients with renal insufficiency. In this study, we investigated the effects of oral treatment with paricalcitol, a potent vitamin D receptor activator, on arterial stiffness and osteopontin, a marker of atherosclerosis, in hypertensive patients with chronic kidney disease (CKD) and secondary hyperparathyroidism.

METHODS

We followed up 29 treated hypertensive patients (mean age: 74.1 years, 19 men, office blood pressure = 132/85 mmHg) with CKD stages 3-5 (mean glomerular filtration rate [GFR] = 19.4 ml/min/1.73 m²) who were on therapy with oral paricalcitol for 1 year. The control group consisted of 10 age-, sex-, and GFR-matched hypertensive patients with secondary hyperparathyroidism.

RESULTS

After 1 year of treatment with paricalcitol compared to baseline, there was no statistical difference in levels of GFR, office blood pressure, and osteopontin (p = NS for all), while carotid-femoral PWV was reduced from 11.8 ± 2.6 m/s to 11.2 ± 2.4 m/s (p < 0.05). The control group exhibited no significant changes in carotid-femoral PWV (p = NS).

CONCLUSIONS

Treatment with oral paricalcitol in hypertensive subjects suffering from CKD stages 3-5 and secondary hyperparathyroidism is accompanied by amelioration of arterial stiffness as reflected by the reduction of carotid-femoral PWV.

The Use of Vitamin D Metabolites and Analogues in the Treatment of Chronic Kidney Disease

Chronic kidney disease (CKD) and end-stage renal disease (ESRD) are associated with abnormalities in bone and mineral metabolism, known as CKD-bone mineral disorder. CKD and ESRD cause skeletal abnormalities characterized by hyperparathyroidism, mixed uremic osteodystrophy, osteomalacia, adynamic bone disease, and frequently enhanced vascular and ectopic calcification. Hyperparathyroidism and mixed uremic osteodystrophy are the most common manifestations due to phosphate retention, reduced concentrations of 1,25-dihydroxyvitamin D, intestinal calcium absorption, and negative calcium balance. Treatment with 1-hydroxylated vitamin D analogues is useful.

Comparison of the Pharmacological Effects of Paricalcitol Versus Calcitriol on Secondary Hyperparathyroidism in the Dialysis Population

Management of secondary hyperparathyroidism (SHPT) in dialysis population includes the use of active vitamin D forms, among which paricalcitol was shown to be more effective at reducing parathyroid hormone (PTH) concentrations. A prospective randomized study comparing the effectiveness and safety of peroral paricalcitol and calcitriol in suppressing PTH concentrations in 20 hemodialysis patients was performed comparing the influence of agents on PTH suppression, calcium (Ca) and phosphate (P) level and calcium-phosphorus product (C×P). The study was performed in an "intent to treat" manner with primary end point in reduction of PTH level in the target area of 150 > PTH < 300 ng/L after 3 months. At the time point 3 months after therapy induction paricalcitol and calcitriol were equally efficient at correcting PTH levels, with paricalcitol showing significantly less calcemic effect than calcitriol.

Comparative efficacy and safety of paricalcitol versus vitamin D receptor activators for dialysis patients with secondary hyperparathyroidism: a meta-analysis of randomized controlled trials

Background

Secondary hyperparathyroidism (SHPT) is a severe complication for dialysis patients. Vitamin D receptor activators (VDRAs) are used to treat SHPT, but the comparative efficacy and safety between paricalcitol and other vitamin D receptor activators for management of SHPT in dialysis patients has been unproven.

Methods

We searched PubMed, Embase, and the Cochrane Library for the time period through June 2017 to identify randomized controlled trials that evaluated paricalcitol compared with other VDRAs for treatment of SHPT. The primary outcome was the percentage of patients with target reduction of intact parathyroid hormone (iPTH) from baseline. Secondary outcomes included incidences of hypercalcemia and hyperphosphatemia. The random-effects model was used to estimate relative risks (RRs) with 95% confidence intervals (CIs).

Results

Eight studies (N = 759) were eligible for final inclusion. Compared with other VDRAs, no significant differences were found in the percentage of patients with target reduction of intact parathyroid hormone (iPTH) from baseline for paricalcitol treatment of SHPT in dialysis patients (RR, 1.01; 95% CI, 0. 87–1.18; p = 0.85). There were no differences in the incidence of hypercalcemia (RR, 0.95; 95% CI, 0.74–1.21; p = 0. 65) and hyperphosphatemia (RR, 0.94; 95% CI, 0.77–1.16; p = 0.58).

Conclusions

The presently available evidence is insufficient to draw a conclusion regarding whether paricalcitol therapy has a comparative efficacy and safety over other VDRAs for treating dialysis patients with SHPT. Large-sample, well-conducted, high-quality RCTs with patient-level outcomes (i.e., mortality) are urgently needed.

Electronic supplementary material

The online version of this article (10.1186/s12882-017-0691-6) contains supplementary material, which is available to authorized users.

Improved regeneration and de novo bone formation in a diabetic zebrafish model treated with paricalcitol and cinacalcet

Bone changes related to diabetes have been well stablished, but few strategies have been developed to prevent this growing health problem. In our work, we propose to investigate the effects of calcitriol as well as of a vitamin D analog (paricalcitol) and a calcimimetic (cinacalcet), in fin regeneration and de novo mineralization in a zebrafish model of diabetes. Following exposure of diabetic transgenic Tg(ins:nfsb-mCherry) zebrafish to calcitriol, paricalcitol and cinacalcet, caudal fins were amputated to assess their effects on tissue regeneration. Caudal fin mineralized and regenerated areas were quantified by in vivo alizarin red staining. Quantitative real-time PCR was performed using RNA from the vertebral column. Diabetic fish treated with cinacalcet and paricalcitol presented increased regenerated and mineralized areas when compared with non-treated diabetic group, while no significant increase was observed in non-diabetic fish treated with both drugs. Gene expression analysis showed an up-regulation for runt-related transcription factor 2b (runx2b), bone gamma-carboxyglutamic acid-containing protein (bglap), insulin a (insa) and insulin b (insb) and a trend of increase for sp7 transcription factor (sp7) in diabetic groups treated with cinacalcet and paricalcitol. Expression of insra and vdra was up-regulated in both diabetic and nondiabetic fish treated with cinacalcet. In nondiabetic fish treated with paricalcitol and cinacalcet a similar increase in gene expression could be observed but not so pronounced. The increased mineralization and regeneration in diabetic zebrafish treated with cinacalcet and paricalcitol can be explained by increased osteoblastic differentiation and increased insulin expression indicating pro-osteogenic potential of both drugs.

Pharmacological Management of Secondary Hyperparathyroidism in Patients with Chronic Kidney Disease

Secondary hyperparathyroidism (SHPT) is a common complication of chronic kidney disease (CKD) and is part of the CKD-mineral bone disorder (CKD-MBD). SHPT is associated with increased risk of fracture and mortality; thus, SHPT control is recommended as kidney function declines. Effective SHPT management becomes more difficult once skeletal and cardiovascular adverse effects associated with severe SHPT have become established. However, interventional studies to lower parathyroid hormone (PTH) have so far shown inconsistent results in improving patient-centred outcomes such as mortality, cardiovascular events and fracture. Pharmacological treatment effect on PTH level is also inconsistent between pre-dialysis CKD and dialysis patients, which adds to the complexity of SHPT management. This review aims to give an overview on the pathophysiology, pharmacological and non-pharmacological treatment for SHPT in CKD including some of the limitations of current therapeutic options.

CYP3A4 is a crosslink between vitamin D and calcineurin inhibitors in solid organ transplant recipients: implications for bone health

The use of calcineurin inhibitors (CNIs) and vitamin D deficiency may contribute to the pathogenesis of post-transplant bone disease. CNIs and 1,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃) are substrates of the drug-metabolizing enzyme CYP3A4. This review summarizes the indications for the use of activated vitamin D analogs in post-transplant care and the current knowledge on the impact of CNIs on bone. We searched for clinical evidence of the interaction between CNIs and 1,25(OH)₂D₃. We also provide an overview of the literature on the interplay between vitamin D metabolism and CYP3A4 in experimental and clinical settings and discuss its possible implications for solid organ transplant recipients. In conclusion, there is a body of evidence on the interplay between vitamin D and the drug-metabolizing enzyme CYP3A4, which may have therapeutic implications.

Secondary Hyperparthyroidism: Pathogenesis, Diagnosis, Preventive and Therapeutic Strategies

Uremic secondary hyperparathyroidism is a multifactorial and complex disease often present in advanced stages of chronic kidney disease. The accumulation of phosphate, the increased FGF23 levels, the reduction in active vitamin D production, and the tendency to hypocalcemia are persistent stimuli for the development and progression of parathyroid hyperplasia with increased secretion of PTH. Parathyroid proliferation may become nodular mainly in cases of advanced hyperparathyroidism. The alterations in the regulation of mineral metabolism, the development of bone disease and extraosseous calcifications are essential components of chronic kidney disease-mineral and bone disorder and have been associated with negative outcomes. The management of hyperparathyroidism includes the correction of vitamin D deficiency and control of serum phosphorus and PTH without inducing hypercalcemia. An update of the leading therapeutic tools available for the prevention and clinical management of secondary hyperparathyroidism, its diagnosis, and the main mechanisms and factors involved in the pathogenesis of the disease will be described in this review.

Secondary Hyperparathyroidism in Chronic Kidney Disease: Focus on Clinical Consequences and Vitamin D Therapies

Objective:

To assess vitamin D–based treatment approaches for secondary hyperparathyroidism and its complications.

Data Sources:

A literature search was performed using MEDLINE (1990–February 28, 2006). Key words used were chronic kidney disease and vitamin D to identify relevant papers published in English.

Study Selection and Data Extraction:

From the database of articles generated, 48 papers were identified. Titles and abstracts were examined to identify those directly related to the objective. Discussion was expanded through the bibliographies of cited articles.

Data Synthesis:

The increasing prevalence of chronic kidney disease (CKD) in the US indicates an urgent need for treatment strategies to delay or prevent disease progression. Abnormalities in phosphorus and calcium homeostasis, vitamin D levels, and the subsequent development of secondary hyperparathyroidism (SHPT) are secondary complications of CKD associated with increased morbidity and mortality. Management options include dietary phosphorus restriction, phosphate binders and/or calcium supplementation, vitamin D supplementation, and calcimimetics. Vitamin D supplementation has received increased attention given the prevalence of vitamin D deficiency in patients with CKD and the beneficial effect of correcting this deficiency.

Conclusions:

Early identification and intervention appropriate to the stage of CKD are likely to improve patient outcomes. Improved knowledge of interactions between vitamin D and vitamin D receptors has led to the development of vitamin D analogs and calcimimetics, which offer benefits in the management of SHPT. Integrating available treatment options into practice to achieve optimal therapeutic goals of SHPT based on the stage of CKD is a significant challenge for pharmacists managing patients with CKD.

Vitamin D-Mediated Hypercalcemia: Mechanisms, Diagnosis, and Treatment

Hypercalcemia occurs in up to 4% of the population in association with malignancy, primary hyperparathyroidism, ingestion of excessive calcium and/or vitamin D, ectopic production of 1,25-dihydroxyvitamin D [1,25(OH)₂D], and impaired degradation of 1,25(OH)₂D. The ingestion of excessive amounts of vitamin D₃ (or vitamin D₂) results in hypercalcemia and hypercalciuria due to the formation of supraphysiological amounts of 25-hydroxyvitamin D [25(OH)D] that bind to the vitamin D receptor, albeit with lower affinity than the active form of the vitamin, 1,25(OH)₂D, and the formation of 5,6-trans 25(OH)D, which binds to the vitamin D receptor more tightly than 25(OH)D. In patients with granulomatous disease such as sarcoidosis or tuberculosis and tumors such as lymphomas, hypercalcemia occurs as a result of the activity of ectopic 25(OH)D-1-hydroxylase (CYP27B1) expressed in macrophages or tumor cells and the formation of excessive amounts of 1,25(OH)₂D. Recent work has identified a novel cause of non-PTH-mediated hypercalcemia that occurs when the degradation of 1,25(OH)₂D is impaired as a result of mutations of the 1,25(OH)₂D-24-hydroxylase cytochrome P450 (CYP24A1). Patients with biallelic and, in some instances, monoallelic mutations of the CYP24A1 gene have elevated serum calcium concentrations associated with elevated serum 1,25(OH)₂D, suppressed PTH concentrations, hypercalciuria, nephrocalcinosis, nephrolithiasis, and on occasion, reduced bone density. Of interest, first-time calcium renal stone formers have elevated 1,25(OH)₂D and evidence of impaired 24-hydroxylase-mediated 1,25(OH)₂D degradation. We will describe the biochemical processes associated with the synthesis and degradation of various vitamin D metabolites, the clinical features of the vitamin D-mediated hypercalcemia, their biochemical diagnosis, and treatment.

Budget impact of secondary hyperparathyroidism treatment in chronic kidney disease in an Ecuadorian social security hospital

BACKGROUND

Chronic kidney disease (CKD) is a disorder with high morbidity and mortality worldwide whose complications generate multiple costs. In Ecuador, only a few healthcare institutions have implemented management protocols aimed to reduce costs and to improve the quality of life of patients. The aim of this study is to evaluate the short-term (1-year) and long-term (5-year) costs and savings in the management of secondary hyperparathyroidism (SHPT) of hemodialyzed CKD patients by comparing calcitriol and paricalcitol in a large social security hospital in Quito, Ecuador.

METHODS

The estimation model assessed the resources used in the management of SHPT by comparing prospectively the cost savings within 1-year and 5-year time horizon with calcitriol and paricalcitol. Hospitalization, erythropoietin (EPO), treatment doses, intravenous iron consumption, and medical supplies were estimated according international references, based on the initial parathormone level (iPTH) of patients. The Ecuadorian National Reference costs (2014-2015) and institutional costs were used to calculate treatment costs. A statistical sensitivity analysis was also performed.

RESULTS

The study was based on data from 354 patients of whom 147 (41.4 %) had a value of iPTH in the range 300-600 pg/ml, 45 (12.8 %) in the range 601-800 pg/ml, and 162 (45.7 %) over 800 pg/ml. The 1-year estimated costs per patient for calcitriol and paricalcitol, respectively, were: medication, 63.88 USD and 1,123.44 USD; EPO, 19,522.95 USD and 16,478 USD; intravenous iron 143.21 USD and 187.76 USD. Yearly hospitalization costs per patient were 11,647.99 USD with calcitriol and 8,019.41 USD with paricalcitol. Total yearly costs per patient amounted to 31,378.02 USD with calcitriol and 25,809.50 USD with paricalcitol. Total savings using paricalcitol were 5,568.52 USD per patient compared with calcitriol. The 5-year cumulative medication costs were 319 USD for calcitriol and 2,403 USD for paricalcitol; EPO with calcitriol was 97,615 USD and with paricalcitol 82,394 USD; intravenous iron with calcitriol was 716 USD and paricalcitol 939 USD. Hospitalization costs for patients with calcitriol and paricalcitol were 43,095 USD and 62,595 USD, respectively. Total savings using paricalcitol amounted 32,414 USD per patient compared with calcitriol.

CONCLUSIONS

Paricalcitol use generated more cost savings than calcitriol after 1 and 5 years.

Chronic Kidney Disease-Mineral and Bone Disorders (CKD-MBDs): What the Endocrinologist Needs to Know

OBJECTIVE

Chronic kidney disease-mineral and bone disorders (CKD-MBDs) are a spectrum of abnormalities involving skeletal hormones, minerals, and bone turnover and mineralization. This paper focuses on what the endocrinologist should know about the assessment and management of skeletal and metabolic disorders in CKD-MBDs.

METHODS

Relevant literature was reviewed to (1) define disturbances of minerals and hormones in the course of CKD; (2) identify the variable radiographic and histomorphometric changes of CKD-MBDs; (3) review the association among CKD-MBDs, vascular calcification, cardiovascular disease (CVD), and mortality; and (4) clarify issues in CKD-MBDs therapy.

RESULTS

Assessment and treatment of CKD-MBDs is complicated by progressive changes in bone minerals and skeletal regulatory hormones as kidney function declines. CKD-MBDs are associated with fracture risk, and studies demonstrate that bone mineral density can be used to assess bone loss and fracture risk in these patients. Treatment of CKD-MBDs continues to evolve. Use of calcium, phosphate binders, vitamin D, vitamin D-receptor analogs, and drugs for osteoporosis and CKD-MBDs treatment are discussed in the context of safety and efficacy for patients with CKD.

CONCLUSION

The association of CKD with bone disease, vascular calcification, CVD, and mortality mandates earlier recognition and treatment of CKD-MBDs. Osteoporosis as a distinct entity can be diagnosed and managed in CKD, although assessment of osteoporosis becomes challenging in late (stage 4 to 5) CKD. Diabetes is common in early (stage 1 to 3) CKD. In addition, 96% of all individuals identified as having CKD have early CKD. The endocrinologist is uniquely positioned to address and treat both diabetes and many of the metabolic and skeletal disorders associated with early CKD-MBDs, including osteoporosis.

Health economic evaluation of paricalcitol(®) versus cinacalcet + calcitriol (oral) in Italy. [corrected]

BACKGROUND AND OBJECTIVE

Chronic kidney disease (CKD) is a highly morbid disorder. The most severe form of CKD is end-stage renal disease (ESRD), in which the patient requires some form of renal replacement therapy to survive. The increasing incidence, prevalence, and costs of ESRD are major national healthcare concerns. The objective of this study was to determine the cost effectiveness of two innovative therapies, paricalcitol versus cinacalcet + calcitriol (oral) in patients with CKD stage 5 (CKD 5) in the healthcare setting in Italy in 2013.

METHODS

A Markov process model was developed employing data sources from the published literature, paricalcitol clinical trials, official Italian price/tariff lists, and national population statistics. The analysis is based on a comparison of treatment with paricalcitol versus cinacalcet + calcitriol (oral) in CKD 5. The perspective of the study was that of the payer [Italian National Health Service (INHS)]. The primary efficacy outcomes in the paricalcitol and cinacalcet + calcitriol (oral) clinical trials (reduction of secondary hyperparathyroidism, complications, and mortality) were extrapolated to effectiveness outcomes: number of life-years gained (LYG) and number of quality-adjusted life-years (QALYs). Clinical and economic outcomes were discounted at 3 %.

RESULTS

The base-case analysis is based on a 5-year time horizon. From the INHS perspective, the use of paricalcitol leads to a cost saving of €1,853 and an increase in LYG (0.136) and a gain in QALYs (0.089). Consequently, the use of paricalcitol is dominant over the use of combination cinacalcet + calcitriol (oral paricalcitol leads to cost savings and a higher effectiveness). Sensitivity analyses confirmed the robustness of the model.

CONCLUSION

The results showed that the favorable clinical benefit of paricalcitol results in positive health economic benefits. This study suggests that the use of paricalcitol in patients with ESRD may be cost effective from the perspective of the INHS.