Novel Biomarkers of Bone Metabolism.

Bone represents a metabolically active tissue subject to continuous remodeling orchestrated by the dynamic interplay between osteoblasts and osteoclasts. These cellular processes are modulated by a complex interplay of biochemical and mechanical factors, which are instrumental in assessing bone remodeling. This comprehensive evaluation aids in detecting disorders arising from imbalances between bone formation and reabsorption. Osteoporosis, characterized by a reduction in bone mass and strength leading to heightened bone fragility and susceptibility to fractures, is one of the more prevalent chronic diseases. Some epidemiological studies, especially in patients with chronic kidney disease (CKD), have identified an association between osteoporosis and vascular calcification. Notably, low bone mineral density has been linked to an increased incidence of aortic calcification, with shared molecules, mechanisms, and pathways between the two processes. Certain molecules emerging from these shared pathways can serve as biomarkers for bone and mineral metabolism. Detecting and evaluating these alterations early is crucial, requiring the identification of biomarkers that are reliable for early intervention. While traditional biomarkers for bone remodeling and vascular calcification exist, they suffer from limitations such as low specificity, low sensitivity, and conflicting results across studies. In response, efforts are underway to explore new, more specific biomarkers that can detect alterations at earlier stages. The aim of this review is to comprehensively examine some of the emerging biomarkers in mineral metabolism and their correlation with bone mineral density, fracture risk, and vascular calcification as well as their potential use in clinical practice.

Chronic kidney disease mineral bone disorder in childhood and young adulthood: a 'growing' understanding.

Chronic kidney disease (CKD) mineral and bone disorder (MBD) comprises a triad of biochemical abnormalities (of calcium, phosphate, parathyroid hormone and vitamin D), bone abnormalities (turnover, mineralization and growth) and extra-skeletal calcification. Mineral dysregulation leads to bone demineralization causing bone pain and an increased fracture risk compared to healthy peers. Vascular calcification, with hydroxyapatite deposition in the vessel wall, is a part of the CKD-MBD spectrum and, in turn, leads to vascular stiffness, left ventricular hypertrophy and a very high cardiovascular mortality risk. While the growing bone requires calcium, excess calcium can deposit in the vessels, such that the intake of calcium, calcium- containing medications and high calcium dialysate need to be carefully regulated. Normal physiological bone mineralization continues into the third decade of life, many years beyond the rapid growth in childhood and adolescence, implying that skeletal calcium requirements are much higher in younger people compared to the elderly. Much of the research into the link between bone (de)mineralization and vascular calcification in CKD has been performed in older adults and these data must not be extrapolated to children or younger adults. In this article, we explore the physiological changes in bone turnover and mineralization in children and young adults, the pathophysiology of mineral bone disease in CKD and a potential link between bone demineralization and vascular calcification.

Pediatric Renal Rickets at a Tertiary Center.

We report clinical and etiological profile of 19 children (10 males) with renal rickets managed in the years 2021-2022. Median (IQR) age of presentation was 60 (18-96) months. The commonest cause was renal tubular acidosis (n=8). Genetic analysis revealed the diagnosis in 83% subjects (5 out of 6 tested).

Cardiovascular calcifications in dialysis patients / Calcifications cardiovasculaires chez le patient dialysé

Patients with advanced chronic kidney disease and those already on dialysis have an increased prevalence of cardiovascular calcifications. They are the cause of severe complications and are associated with a reduced life expectancy in these patients. Recommendations and imaging scores have been developed to detect and assess their importance, to guide and improve the management of cardiovascular risk. However, despite these recommendations, current practice teaches us that they are only partially applied. The prevention and treatment of cardiovascular calcifications go through the correction of classic risk factors associated with atherosclerosis, mineral and bone metabolism disorders and by optimizing the dose and the efficiency of dialysis. New therapeutic strategies are beginning to emerge, others are being evaluated, such as sodium thiosulfate, rheopheresis, vitamin K, magnesium supplementation, and SNF-472.

Les patients atteints de maladie rénale chronique (MRC) avancée et ceux déjà traités par dialyse présentent une prévalence accrue de calcifications cardiovasculaires. Elles sont à l'origine des complications sévères et s'associent à une diminution de l'espérance de vie chez ces patients. Des recommandations et des scores radiographiques ont été développés pour dépister et évaluer leur importance, afin d'orienter et améliorer la prise en charge du risque cardiovasculaire. Cependant, en dépit de ces recommandations, la pratique courante nous enseigne qu'elles ne sont que partiellement appliquées. La prévention et le traitement de calcifications cardiovasculaires passent par la correction des facteurs de risque classiques associés à l'athérosclérose, des troubles du métabolisme minéral et osseux et en optimisant la dose et l'efficacité de la dialyse. Des nouvelles stratégies thérapeutiques commencent à voir le jour, d'autres sont en cours d'évaluation, comme le thiosulfate de sodium, la rhéophérèse, la vitamine K, la supplémentation en magnésium et le SNF-472.

Secondary hyperparathyroidism in chronic kidney disease: pathomechanism and current treatment possibilities.

Secondary hyperparathyroidism (SHPT) is one of the most common metabolic complications resulting from chronic kidney disease (CKD). The complexity of calcium and phosphate disorders associated with CKD is defined by the Kidney Disease Improvement Global Outcomes (KDIGO) working group as CKD-related mineral and bone disorders (CKD-MBD). The last update of the KDIGO guidelines on the conduct in CKD-MBD was published in 2017. The treatment of SHPT is based on 2 strategies: counteracting hyperphosphataemia and suppressing parathyroid hormone (PTH) secretion. Therapy should be based on optimally selected drugs, taking into account additional effects to reduce the risk of chronic complications and side effects. The creation of new drugs with a better safety profile, significant reduction of side effects, and greater efficiency in achieving target serum phosphorus and PTH values forces the gradual replacement of existing treatment with new pharmacotherapies. The aim of this study is to discuss the latest issues (in connection with the latest KDIGO guidelines) regarding the pathomechanism of secondary hyperparathyroidism and the current directions of the therapy in these disorders.

Mixed uremic osteodystrophy: an ill-described common bone pathology in patients with chronic kidney disease.

Renal osteodystrophy (ROD) starts early and progresses with further loss of kidney function in patients with chronic kidney disease (CKD). There are four distinct types of ROD based on undecalcified bone biopsy results. Adynamic bone disease and osteomalacia are the predominant forms of low bone turnover, while hyperparathyroid bone disease and mixed uremic osteodystrophy (MUO) are typically associated with high bone turnover. MUO is a prevalent but poorly described pathology that demonstrates evidence of osteomalacia on top of the high bone formation/resorption. The prevalence of MUO ranges from 5 to 63% among different studies. The pathogenesis of MUO is multi-factorial. Altered phosphate homeostasis, hypocalcemia, vitamin D deficiency, increased FGF-23, interleukins 1 and 6, TNF-α, amyloid, and heavy metal accumulation are the main inducers of MUO. The clinical findings of MUO are usually non-specific. The use of non-invasive testing such as bone turnover markers and imaging techniques might help to suspect MUO. However, it is usually impossible to precisely diagnose this condition without performing bone biopsy. The principal management of MUO is to control the maladaptive hyperparathyroidism along with correcting any nutritional mineral deficiencies that may induce mineralization defect. MUO is a common but still poorly understood bone pathology category; it demonstrates the complexity and difficulty in understanding ROD. A large prospective bone biopsy-based studies are needed for better identification as proper diagnosis and management would improve the outcome of patients with MUO.

A meta-analysis of randomized controlled trials of tonifying kidney and strengthen bone therapy on nondialysis patients with chronic kidney disease-mineral and bone disorder.

BACKGROUND: Correction of calcium, phosphorus, and parathyroid hormone disorders is the standard of treatment in nondialysis patients with chronic kidney disease-mineral and bone disorder (CKD-MBD). However, the side effects and adverse reactions are still the main problems. Moreover, the lack of protection of kidney function in the treatment dramatically affects patients' health. Although Traditional Chinese Medicine, specifically tonifying kidney and strengthen bone (TKSB) therapy, is wildly applied to patients with CKD-MBD in China, the evidence of TKSB therapy in the treatment of CKD-MBD is limited. Thus, we conducted this meta-analysis to evaluate the efficacy and safety of TKSB therapy combined with Western medicine (WM) for nondialysis patients with CKD-MBD. METHODS: Two investigators conducted systematic research of randomized controlled trials of TKSB therapy for CKD-MBD from 7 electronic databases. Methodological quality evaluations were performed using the Cochrane collaboration tool, and data analysis was conducted by RevMan v5.3 software and STATA v15.0. RESULTS: In total, 8 randomized controlled trials involving 310 patients met the criteria of meta-analysis. The complete results showed that compared with WM alone, TKSB treatment could improve the clinical efficacy rate (risk ratio = 4.49, 95% confidence interval [CI]: [2.64, 7.61], P  .00001), calcium (weighted mean difference [WMD] = 0.11, 95% CI: [0.08, 0.14], P < .00001), serum creatinine (WMD = 45.58, 95% CI: [32.35, 58.8], P < .00001) phosphorus (WMD = 0.11, 95% CI: [0.08, 0.13], P < .00001), parathyroid hormone (WMD = 16.72, 95% CI: [12.89, 20.55], P < .00001), blood urea nitrogen levels (WMD = 0.95, 95% CI: [0.26, 1.64], P = .007) on nondialysis patients with CKD-MBD, which was beneficial to improve the patients' bone metabolic state and renal function. In addition, evidence shows that, compared with WM alone, TKSB treatment is safe and does not increase side effects. CONCLUSION: The systematic review found that TKSB therapy combined with WM has a positive effect on improving renal function and correcting bone metabolism disorder in nondialysis patients with CKD-MBD, which shows that Traditional Chinese Medicine is effective and safe in treating CKD-MBD. However, more high-quality, large-sample, multicenter clinical trials should be conducted to assess the safety and efficacy of TKSB therapy in treating nondialysis patients with CKD-MBD.Systematic review registration: INPLASY2020120086.

Association of incidence rate of spontaneous tendon rupture and renal bone disease in end-stage renal disease patients' cohort.

INTRODUCTION: Spontaneous tendon rupture (STR) is one of the complications related to hyperparathyroidism. This study aims to verify this and to elucidate the feasibility of combined incidence rate of STR and bony fracture to assess clinical management of renal bone disease in dialysis cohort. METHOD: This is a clinical audit of cases of STR and fracture with 5504 patient-year dialysis vintage over 10 years. In order to verify the risk factor, comparison of cases of tendon rupture, the gender, and dialysis vintage matched patients without tendon rupture were done, followed by comparison with post-parathyroidectomy patients. RESULT: Six cases of STR involving eight tendons were identified, including a case of concurrent tendon rupture and bony fracture. These include two cases of double tendons ruptures. During this time, there were 15 cases of bony fracture without tendon rupture. The overall incidence rate for STR and fracture was of 0.0011 and 0.0029 incidence per year of dialysis vintage or one case per 917 and 344 patient-year dialysis vintage, respectively. For patients with PTH ≥ 600 pg/mL, the incidence rate of tendon rupture and fracture was 0.0199 and 0.0430 incidence per person-years or one case per 50 and 23 person-years, respectively. For patients with PTH < 600 pg/mL, the respective rate was 0 and 0.0006 incidence per person-years or one case per >5202 and 1734 person-years. There was significant difference for incidence rates of tendon rupture and fracture between these two groups, with six incidences of tendon rupture per 302 patient-dialysis-years of PTH ≥ 600 pg/mL versus 0 incidence per 5202 patient-year dialysis vintage of PTH < 600 pg/mL (p < 0.001). In similar comparison, there was also significant difference for incidence rate of fracture with 13/302 versus 2/5202 (p < 0.001). In the 5 yearly audit over 10 years, the incidence rates of tendon rupture and fracture have dropped from 0.0052 to 0.0028 or one incidence per 192 to 356 person-years. Among 35 patients post-parathyroidectomy, there was an incidence of tendon rupture in a patient with recurrence of hyperparathyroidism, 5 years after surgery. Comparing six survived patients with tendon rupture versus 12 age-gender-dialysis vintage matched patients, hyperparathyroidism has been shown to be most important risk factor. And subsequently, comparing them with six post-parathyroidectomy patients, reduction of alkaline phosphatase (ALP) has been shown to be associated with lower risk of tendon rupture. Median survival in patients with history of tendon rupture and those with history of fracture was 5.9 and 2.2 years, respectively (p = 0.192). CONCLUSION: Although rare, end-stage renal failure patients on dialysis with PTH > 600 pg/mL had high risk of tendon rupture and bony fracture. Parathyroidectomy might reduce the risk of tendon rupture and fracture with lowering ALP signifying reduction in bone turn over. Combined incidence rate of tendon rupture and fracture could be used to assess the control of hyperparathyroidism related issues in dialysis center.

Dentoalveolar Alterations in an Adenine-Induced Chronic Kidney Disease Mouse Model.

Chronic kidney disease (CKD) is characterized by kidney damage and loss of renal function. CKD mineral and bone disorder (CKD-MBD) describes the dysregulation of mineral homeostasis, including hyperphosphatemia and elevated parathyroid hormone (PTH) secretion, skeletal abnormalities, and vascular calcification. CKD-MBD impacts the oral cavity, with effects including salivary gland dysfunction, enamel hypoplasia and damage, increased dentin formation, decreased pulp volume, pulp calcifications, and altered jaw bones, contributing to clinical manifestations of periodontal disease and tooth loss. Underlying mechanisms are not fully understood, and CKD mouse models commonly require invasive procedures with high rates of infection and mortality. We aimed to characterize the dentoalveolar effects of an adenine diet (AD)-induced CKD (AD-CKD) mouse model. Eight-week-old C57BL/6J mice were provided either a normal phosphorus diet control (CTR) or adenine and high-phosphorus diet CKD to induce kidney failure. Mice were euthanized at 15 weeks old, and mandibles were collected for micro-computed tomography and histology. CKD mice exhibited kidney failure, hyperphosphatemia, and hyperparathyroidism in association with porous cortical bone in femurs. CKD mice showed a 30% decrease in molar enamel volume compared to CTR mice. Enamel wear was associated with reduced ductal components, ectopic calcifications, and altered osteopontin (OPN) deposition in submandibular salivary glands of CKD mice. Molar cusps in CKD mice were flattened, exposing dentin. Molar dentin/cementum volume increased 7% in CKD mice and pulp volume decreased. Histology revealed excessive reactionary dentin and altered pulp-dentin extracellular matrix proteins, including increased OPN. Mandibular bone volume fraction decreased 12% and bone mineral density decreased 9% in CKD versus CTR mice. Alveolar bone in CKD mice exhibited increased tissue-nonspecific alkaline phosphatase localization, OPN deposition, and greater osteoclast numbers. AD-CKD recapitulated key aspects reported in CKD patients and revealed new insights into CKD-associated oral defects. This model has potential for studying mechanisms of dentoalveolar defects or therapeutic interventions. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Role of Chronic Kidney Disease (CKD)-Mineral and Bone Disorder (MBD) in the Pathogenesis of Cardiovascular Disease in CKD.

Cardiovascular disease (CVD) is the leading cause of death in patients with chronic kidney disease (CKD). Multiple factors account for the increased incidence of cardiovascular morbidity and mortality in patients with CKD. Traditional risk factors for atherosclerosis and arteriosclerosis, including age, hypertension, dyslipidemia, diabetes mellitus, and smoking, are also risk factors for CKD. Non-traditional risk factors specific for CKD are also involved in CVD pathogenesis in patients with CKD. Recently, CKD-mineral and bone disorder (CKD-MBD) has emerged as a key player in CVD pathogenesis in the context of CKD. CKD-MBD manifests as hypocalcemia and hyperphosphatemia in the later stages of CKD; however, it initially develops much earlier in disease course. The initial step in CKD-MBD involves decreased phosphate excretion in the urine, followed by increased circulating concentrations of fibroblast growth factor 23 (FGF23) and parathyroid hormone (PTH), which increase urinary phosphate excretion. Simultaneously, the serum calcitriol concentration decreases as a result of FGF23 elevation. Importantly, FGF23 and PTH cause left ventricular hypertrophy, arrhythmia, and cardiovascular calcification. More recently, calciprotein particles, which are nanoparticles composed of calcium, phosphate, and fetuin-A, among other components, have been reported to cause inflammation, cardiovascular calcification, and other clinically relevant outcomes. CKD-MBD has become one of the critical therapeutic targets for the prevention of cardiovascular events and is another link between cardiology and nephrology. In this review, we describe the role of CKD-MBD in the pathogenesis of cardiovascular disorders and present the current treatment strategies for CKD-MBD.

Recommendations of the Spanish Society of Nephrology for the management of mineral and bone metabolism disorders in patients with chronic kidney disease: 2021 (SEN-MM).

As in 2011, when the Spanish Society of Nephrology (SEN) published the Spanish adaptation to the Kidney Disease: Improving Global Outcomes (KDIGO) universal Guideline on Chronic Kidney Disease-Mineral and Bone Disorder (CKD-MBD), this document contains an update and an adaptation of the 2017 KDIGO guidelines to our setting. In this field, as in many other areas of nephrology, it has been impossible to irrefutably answer many questions, which remain pending. However, there is no doubt that the close relationship between the CKD-MBD/cardiovascular disease/morbidity and mortality complex and new randomised clinical trials in some areas and the development of new drugs have yielded significant advances in this field and created the need for this update. We would therefore highlight the slight divergences that we propose in the ideal objectives for biochemical abnormalities in the CKD-MBD complex compared to the KDIGO suggestions (for example, in relation to parathyroid hormone or phosphate), the role of native vitamin D and analogues in the control of secondary hyperparathyroidism and the contribution of new phosphate binders and calcimimetics. Attention should also be drawn to the adoption of important new developments in the diagnosis of bone abnormalities in patients with kidney disease and to the need to be more proactive in treating them. In any event, the current speed at which innovations are taking place, while perhaps slower than we might like, globally drives the need for more frequent updates (for example, through Nefrología al día).

Association between CKD-MBD and mortality in older patients with advanced CKD-results from the EQUAL study.

BACKGROUND: Chronic kidney disease-mineral and bone disorder (CKD-MBD) is a common complication of CKD; it is associated with higher mortality in dialysis patients, while its impact in non-dialysis patients remains mostly unknown. We investigated the associations between parathyroid hormone (PTH), phosphate and calcium (and their interactions), and all-cause, cardiovascular (CV) and non-CV mortality in older non-dialysis patients with advanced CKD. METHODS: We used data from the European Quality study, which includes patients aged ≥65 years with estimated glomerular filtration rate ≤20 mL/min/1.73 m2 from six European countries. Sequentially adjusted Cox models were used to assess the association between baseline and time-dependent CKD-MBD biomarkers and all-cause, CV and non-CV mortality. Effect modification between biomarkers was also assessed. RESULTS: In 1294 patients, the prevalence of CKD-MBD at baseline was 94%. Both PTH [adjusted hazard ratio (aHR) 1.12, 95% confidence interval (CI) 1.03-1.23, P = .01] and phosphate (aHR 1.35, 95% CI 1.00-1.84, P = .05), but not calcium (aHR 1.11, 95% CI 0.57-2.17, P = .76), were associated with all-cause mortality. Calcium was not independently associated with mortality, but modified the effect of phosphate, with the highest mortality risk found in patients with both hypercalcemia and hyperphosphatemia. PTH level was associated with CV mortality, but not with non-CV mortality, whereas phosphate was associated with both CV and non-CV mortality in most models. CONCLUSIONS: CKD-MBD is very common in older non-dialysis patients with advanced CKD. PTH and phosphate are independently associated with all-cause mortality in this population. While PTH level is only associated with CV mortality, phosphate seems to be associated with both CV and non-CV mortality.

Effects of Plant-Based Protein Consumption on Kidney Function and Mineral Bone Disorder Outcomes in Adults With Stage 3-5 Chronic Kidney Disease: A Systematic Review.

INTRODUCTION: Plant-based protein is of growing interest for dietary management of chronic kidney disease (CKD) and is hypothesized to preserve kidney function and reduce CKD-mineral bone disorder (MBD) complications, among other benefits. This systematic review aimed to summarize the available clinical trial evidence for the effect of plant-based protein on kidney function and CKD-MBD outcomes in adults with stage 3-5 CKD not on dialysis. METHODS: Searches of Medline, Embase, Agricola, CAB abstracts, Web of Science, Scopus, and hand searching were performed. Clinical trials with ≥8 participants ≥18 years of age with an estimated glomerular filtration rate <60 mL/min/1.73 m2 but not on dialysis were included. Additionally, only clinical trials with ≥1-week interventions with ≥50% dietary protein from plant-based sources and reported at least one outcome for both kidney function and CKD-MBD outcomes were included. Of the 10,962 identified abstracts, 32 met inclusion criteria and were assessed for risk of bias. RESULTS: Results for kidney function and CKD-MBD outcomes were heterogenous, with most studies having suboptimal methodological quality. In most of the studies (27/32), protein source was altered only secondarily to low-protein diet interventions. Thus, data synthesis and interpretation were focused on a subset of five studies that investigated a change in protein source only (i.e., animal vs. plant). Of this subset, four studies reported no change in kidney function, while one study reported a decrease. Three studies reported no change in serum phosphorus, and one study reported lower serum phosphorus following a vegetarian diet. Further, limited data and inconclusive results were observed for phosphaturic hormones, parathyroid hormone, and fibroblast growth factor-23. CONCLUSION: Current clinical trial evidence on plant-based protein interventions for preserving kidney function and preventing CKD-MBD is limited to inform clinical guidelines at this time. This systematic review emphasizes the ongoing need to research the effects of plant-based protein on kidney function and CKD-MBD outcomes.

Impact of Cinacalcet and Etelcalcetide on Bone Mineral and Cardiovascular Disease in Dialysis Patients.

PURPOSES OF REVIEW: With chronic kidney disease (CKD) progression, secondary hyperparathyroidism (sHPT) and mineral and bone metabolism disease (MBD) almost inevitably develop and result in renal osteodystrophy and cardiovascular disease (CVD). Together with active vitamin D, calcimimetics are the main therapy for sHPT in CKD. This review provides an overview of the therapeutic effects of oral cinacalcet and intravenous etelcalcetide on CKD-MBD and vascular disease, with a focus on pediatric dialysis patients. RECENT FINDINGS: Randomized controlled trials in adults and children demonstrate efficient lowering of parathyroid hormone (PTH) by the calcimimetics together with a reduction in serum calcium and phosphate when combined with low-dose active vitamin D, while therapy with active vitamin D analogs alone increases serum calcium and phosphate. Cinacalcet and etelcalcetide both improve bone formation and correct adynamic bone, i.e., have a direct bone anabolic effect. They decrease serum calciprotein particles, which are involved in endothelial dysfunction, atherogenesis, and vascular calcification. Clinical trials in adults suggest a modest slowing of the progression of cardiovascular calcification with cinacalcet. Calcimimetic agents represent a major pharmacological tool for improved control of CKD-MBD, by efficiently counteracting sHPT and allowing for better control of calcium/phosphate and bone homeostasis. Albeit definite evidence is lacking, the beneficial effects of calcimimetics on CVD are promising. Routine use of cinacalcet has been suggested in children.

FGF23 Actions in CKD-MBD and other Organs During CKD.

Fibroblast growth factor 23 (FGF23) is a new endocrine product discovered in the past decade. In addition to being related to bone diseases, it has also been found to be related to kidney metabolism and parathyroid metabolism, especially as a biomarker and a key factor to be used in kidney diseases. FGF23 is upregulated as early as the second and third stages of chronic kidney disease (CKD) in response to relative phosphorus overload. The early rise of FGF23 has a protective effect on the body and is essential for maintaining phosphate balance. However, with the decline in renal function, eGFR (estimated glomerular filtration rate) declines, and the phosphorus excretion effect caused by FGF23 is weakened. It eventually leads to a variety of complications, such as bone disease (Chronic Kidney Disease-Mineral and Bone Metabolism Disorder), vascular calcification (VC), and more. Monoclonal antibodies against FGF23 are currently used to treat genetic diseases with increased FGF23. CKD is also a state of increased FGF23. This article reviews the current role of FGF23 in CKD and discusses the crosstalk between various organs under CKD conditions and FGF23. Studying the effect of hyperphosphatemia on different organs of CKD is important. The prospect of FGF23 for therapy is also discussed.

Target phosphate and calcium levels in patients undergoing hemodialysis: a post-hoc analysis of the LANDMARK study.

BACKGROUND: It is necessary to re-examine the optimal phosphate (P) and calcium (Ca) target values in the contemporary management of chronic kidney disease-mineral and bone disorder to reduce the risks of cardiovascular events in patients receiving hemodialysis. METHODS: We performed a post-hoc analysis of the LANDMARK study. The outcomes were defined as cardiovascular events and all-cause death. Data from 2135 patients receiving hemodialysis at risk of vascular calcification were analyzed using a time-dependent Cox proportional hazard model adjusted for background factors. RESULTS: On the hazard ratio (HR) curve, the ranges where the lower 95% confidence interval (CI) were below the minimum of HR (= 1.00) were as follows: P = 3.5-5.5 mg/dL; albumin-adjusted Ca < 9.1 mg/dL for cardiovascular events; and P = 3.6-5.3 mg/dL; albumin-adjusted Ca < 9.1 mg/dL for all-cause mortality. In stratified analysis, the HRs for cardiovascular events in P < 3.5 mg/dL and P ≥ 5.5 mg/dL were similar to that of P = 3.5-5.5 mg/dL (P ≥ 0.05), and albumin-adjusted Ca ≥ 9.1 mg/dL had higher HR than values < 9.1 mg/dL [1.30 (95% CI 1.00-1.68; P = 0.046)]. For all-cause mortality, the HR in P < 3.6 mg/dL was higher than that in P = 3.6-5.3 mg/dL [1.76 (95% CI 1.25-2.48; P = 0.001)], while the HRs between P ≥ 5.3 mg/dL and P = 3.6-5.3 mg/dL as well as those between albumin-adjusted Ca ≥ 9.1 and < 9.1 mg/dL were not significantly different (P ≥ 0.05). CONCLUSIONS: Managing albumin-adjusted Ca < 9.1 mg/dL may reduce the cardiovascular risk among patients undergoing hemodialysis. Hypophosphatemia < 3.6 mg/dL may be associated with mortality.

Treatment of secondary hyperparathyroidism in non-dialysis CKD: an appraisal 2022s.

The situation of secondary hyperparathyroidism (SHPT) in chronic kidney disease patients not on dialysis (ND-CKD) is probably best characterised by the Kidney Disease: Improving Global Outcomes Chronic Kidney Disease-Mineral and Bone Disorder Update 2017 guideline 4.2.1 stating that the optimal parathyroid hormone levels are not known in these stages. Furthermore, new caution became recommended with regard to the routine use of active vitamin D analogues in early CKD stages and moderate SHPT phenotypes, due to their potential risks for hypercalcaemia and hyperphosphataemia aggravation. Nevertheless, there is still a substantial clinical need to prevent the development of parathyroid gland autonomy, with its associated consequences of bone and vascular damage, including fracture risks and cardiovascular events. Therefore we now attempt to review the current guideline-based and clinical practice management of SHPT in ND-CKD, including their strengths and weaknesses, favouring individualised approaches respecting calcium and phosphate homeostasis. We further comment on extended-release calcifediol (ERC) as a new differential therapeutic option now also available in Europe and on a potentially novel understanding of a required vitamin D saturation in more advanced CKD stages. There is no doubt, however, that knowledge gaps will remain unless powerful randomised controlled trials with hard and meaningful endpoints are performed.

Roxadustat improves renal osteodystrophy by dual regulation of bone remodeling.

PURPOSE: Renal osteodystrophy (ROD), a component of chronic kidney disease-mineral and bone disorder (CKD-MBD) can lead to bone loss increasing fracture risks in CKD patients. Therefore, it is important to prevent and treat ROD. Activation of hypoxia-inducible factor-1α (HIF-1α) signaling was reported to prevent osteoporotic bone loss. Roxadustat, which is used to treat renal anemia in the clinic, is a novel HIF stabilizer. In our study, we aimed to investigate the effects of roxadustat on ROD. METHODS: We established an adenine-induced CKD rat model. Roxadustat was administered intragastrically to normal and CKD rats for 4 weeks. Hemoglobin concentrations and serum biochemical parameters were tested, and bone histomorphometric analysis was performed. RESULTS: CKD rats exhibited impaired renal function with anemia, secondary hyperparathyroidism and high-turnover ROD-induced significant bone loss. Roxadustat ameliorated renal anemia and attenuated the extreme increase in intact parathyroid hormone (iPTH) and fibroblast growth factor 23 (FGF23) in CKD rats. Bone histomorphometric analysis showed that roxadustat significantly alleviated bone loss and bone microarchitecture deterioration in CKD rats by increasing osteoblast activity and inhibiting osteoclast activity. We did not find that roxadustat had significant effects on bone metabolism in normal rats. CONCLUSION: Roxadustat can improve ROD via dual regulation of bone remodeling. The use of roxadustat may be a promising strategy to treat osteoporotic bone disorders, such as ROD.

Mechanistic insights into CKD-MBD-related vascular calcification and its clinical implications.

Chronic Kidney Disease (CKD) is linked to a rising prevalence of morbidity and mortality primarily from cardiovascular complications and is considered a high or very high-risk associated cardiovascular state. These poor outcomes are associated with CKD-mineral and bone disorders (CKD-MBD) in CKD patients, which are manifested by vascular calcification. Patients with chronic renal illness have not only accelerated intimal and medial calcification, but heart valves, and possibly the myocardium get also calcified, as well as the uncommon state of calcific uremic arteriolopathy (calciphylaxis). So the CKD-MBD associated vascular calcification might be a key mediator for an array of cardiovascular sequelae. Various routes link vascular calcification with CKD including the involvement of non-traditional risk factors but still, mechanisms are incompletely understood, and focused treatments have been slow to emerge. Major events and factors in vascular calcification involve the conversion of vascular smooth muscles cells into chondrocyte-like cells. Further dysregulation of calcium, phosphate, parathyroid hormone (PTH), Vitamin D hormonal system, phosphorous, and imbalance of promoters and inhibitors (Fetuin-A and Vitamin K dependent matrix Gla protein) plays the important role in promoting CKD-MBD associated vascular calcification. Fibroblast growth factor-23 (FGF-23), Sclerostin, and Klotho are thought to be the emerging factors involved in the CKD-MBD leading to vascular calcification process and cardiovascular mortality. This review summarizes the brief pathological basis of vascular calcification in CKD, current and emerging approaches including the vast arrangement of contributors and inhibitors for the early identification and treatment.

The current status of chronic kidney disease-mineral and bone disorder management in China.

Chronic kidney disease-mineral and bone disorder (CKD-MBD) is one of the most common complications of patients with chronic kidney disease (CKD). After considering updated international and domestic CKD-MBD management guidelines, the current management status of CKD-MBD in China remains unclear. We aimed to investigate the management status of CKD-MBD in China. A nationwide survey was combined with a real-world study from Sichuan. Targets recommended in KDIGO 2017 and Chinese 2019 guidelines were used as targets. We compared the data between Sichuan from western China and the eastern developed areas of China, and also compared the results of the real-world data from Sichuan with those of DOPPS5. In the questionnaire, a total of 51,039 maintenance hemodialysis (MHD) patients from 272 centers were involved. Estimated achievement rates for Ca (2.1-2.5 mmol/L), P (1.13-1.78 mmol/L), and iPTH (150-600 pg/mL) levels were 57.1%, 41.1% and 52.0%, respectively. Differences in MBD management between Sichuan from questionnaire and central region. In the real-world survey, a total of 7,053 patients were enrolled. Among them, 57.6%, 24.3%, and 55.0% of patients met corrected Ca, serum P, and iPTH targets specified in Chinese 2019 guidelines, respectively. The comprehensive achievement rate was 7.5%. There are differences in MBD management between Sichuan and DOPPS5 regions, with Sichuan being relatively poorer. The level of the above parameters varies among different genders, age groups, and hospital grades. The achievement rate of serum P was higher in tertiary hospitals and elderly patients (P < 0.05). Current MBD management is poor. Phosphate levels in patients treated in secondary and lower hospitals and young dialysis patients should be strengthened.