Phosphorus Regulation in Chronic Kidney Disease

Changes in Bone Mineral Density in Patients With Non-dialysis-Dependent Chronic Kidney Disease Are Associated With Body Composition

OBJECTIVE

Chronic kidney disease (CKD) and low bone mineral density (BMD) are highly prevalent and can co-exist. Parameters of mineral metabolism are associated with BMD in CKD, but other contributing factors may contribute. The aim of this study was to assess changes in BMD and its determinants in patients with nondialysis-dependent CKD (NDD-CKD).

METHODS

Body composition and biochemical profiles were assessed in a retrospective hospital-based cohort study of patients with NDD-CKD. BMD, lean soft tissue (LST), appendicular LST (ALST), and percentage fat mass were assessed by dual-energy X-ray absorptiometry. The ALST index (ALSTI, ALST/height2) and load-capacity index (LCI, fat mass/LST) were calculated. Low BMD was defined as T-score ≤ -1.0.

RESULTS

The mean time between assessments was 2.8 ± 1.3 years; 46 patients were included. A reduction in renal function was observed. Changes in body composition included reductions in ALST (P = .031), ALSTI (P = .021), a trend for BMD (P = .053), and an increase in percentage fat mass (P = .044) and LCI (P = .032). Females had a reduction in BMD (P = .034), ALST (P = .026), and ALSTI (P = .037). Patients with low BMD at baseline had lower LST (P = .013), ALST (P = .023), and percentage fat mass (P = .037) than those with normal BMD. Additionally, reductions in LST (P = .041), ALST (P = .006), and ALSTI (P = .008) were observed in patients who had low BMD at baseline, while no significant changes in body composition were observed in those with normal BMD at baseline. The following body composition parameters at baseline were determinants of BMD status at follow-up: LST (odds ratio [OR]: 0.899, 95% confidence interval [CI]: 0.829-0.976, P = .010), ALST (OR: 0.825, 95% CI: 0.704-0.967, P = .017), and ALSTI (OR: 0.586, 95% CI: 0.354-0.968, P = .037), independent of fat mass and LCI.

CONCLUSIONS

Detrimental body composition changes were observed without changes in body weight; these were more significant in females. Moreover, this is the first longitudinal study showing a protective effect of LST against BMD loss in patients with NDD-CKD.

Exposome and Metabolome Analysis of Sugarcane Workers Reveals Predictors of Kidney Injury

Introduction

Sugarcane workers are exposed to potentially hazardous agrochemicals, including pesticides, heavy metals, and silica. Such occupational exposures present health risks and have been implicated in a high rate of kidney disease seen in these workers.

Methods

To investigate potential biomarkers and mechanisms that could explain chronic kidney disease (CKD) among this worker population, paired urine samples were collected from sugarcane cutters at the beginning and end of a harvest season in Guatemala. Workers were then separated into 2 groups, namely those with or without kidney function decline (KFD) across the harvest season. Urine samples from these 2 groups underwent elemental analysis and untargeted metabolomics.

Results

Urine profiles demonstrated increases in silicon, certain pesticides, and phosphorus levels in all workers, whereas heavy metals remained low. The KFD group had a reduction in estimated glomerular filtration rate (eGFR) across the harvest season; however, kidney injury marker 1 did not significantly change. Cross-harvest metabolomic analysis found trends of fatty acid accumulation, perturbed amino acid metabolism, presence of pesticides, and other known signs of impaired kidney function.

Conclusion

Silica and certain pesticides were significantly elevated in the urine of sugarcane workers with or without KFD. Future work should determine whether long-term occupational exposure to silica and pesticides across multiple seasons contributes to CKD in these workers. Overall, these results confirmed that multiple exposures are occurring in sugarcane workers and may provide insight into early warning signs of kidney injury and may help explain the increased incidence of CKD among agricultural workers.

Calcium/phosphate ratio: an additional tool for the clinical management of asymptomatic primary hyperparathyroidism?

PURPOSE

Serum calcium/phosphate ratio (Ca/P) has been recently proposed as an additional tool to identify primary hyperparathyroidism (PHPT), especially in patients with subclinical presentation, with a proposed cut-off of 3.3 when both values are expressed in mg/dL. No data are available on the relationship between Ca/P and the clinical presentation of PHPT. We thus evaluated this relationship in a large, single-center, unselected series.

METHODS

515 consecutive PHPT patients (mean age 65 ± 13.15 years, 77.1% females) were retrospectively evaluated at diagnosis.

RESULTS

Mean Ca/P was 4.54 ± 1.5 (range 2.36-13.9), being higher than 3.3 in 88.5% of patients. Ca/P was significantly higher in (1) males, (2) symptomatic PHPT, (3) patients with 25-hydroxy vitamin D levels lower than 20 μg/L, (4) patients with osteitis fibrosa cystica, (5) patients with T score < - 2.5 at the radial site. In a multivariate regression analysis, Ca/P resulted significantly associated with PTH levels. After the exclusion of 57 patients with asymptomatic PHPT (aPHPT) patients and serum Ca higher than 1 mg/dL above the upper limit of normal range, no differences were found in Ca/P between aPHPT meeting or not surgical criteria.

CONCLUSIONS

In PHPT Ca/P ratio is associated with increased biochemical and clinical severity of disease and represents a direct indicator of clinical bone damage. However, it does not seem an additional tool to identify aPHPT patients reaching surgical indication.

Evaluation of laboratory values affecting mortality of end-stage renal disease patients: a competing risks approach

BACKGROUND

Chronic Kidney Disease (CKD) is a prevalent and life-threatening situation recognized as an emerging health issue. The present study aimed to evaluate the effect of demographic and laboratory parameters on the survival of patients with End-Stage Renal Disease (ESRD) in a hemodialysis (HD) center in Iran.

MATERIALS AND METHODS

This study was conducted on patients receiving chronic HD in Iran Helal Pharmaceutical and Clinical Complex between 2014 and 2018. The survival time was considered as the time interval between HD initiation and death. Receiving kidney transplantation was regarded as a competing risk, and an improper form of two-parameter Weibull distribution was utilized to simultaneously model the time to both death and renal transplantation. The Bayesian approach was conducted for parameters estimation.

RESULTS

Overall, 29 (26.6%) patients expired, and 19 (17.4%) received kidney transplants. The male gender was related to poor survival, having nearly 4.6 folds higher hazard of mortality (90% HPD region: 1.36-15.49). Moreover, Serum calcium levels [Formula: see text]9.5 mg/dL (adjusted Sub-hazard ratio (S-HR)=2.33, 90% HPD region: 1.05-5.32) and intact parathyroid hormone (iPTH) [Formula: see text]150 pg/mL (adjusted S-HR = 2.56, 90% HPD region: 1.09-6.15) were associated with an elevated hazard of mortality. The cumulative incidence function (CIF) for transplantation was greater than death in the first two years of the study. Subsequently, the CIF for death exceeded transplantation in the following two years. The 4-year cumulative incidence of death and kidney transplantation was 63.7% and 36.3%, respectively.

CONCLUSION

Male gender, hypercalcemia, and hypoparathyroidism were associated with worse outcomes. Correcting mentioned laboratory parameters may improve patients' survival in the HD population.

Comparison of the Health Status of Vegetarians and Omnivores Based on Biochemical Blood Tests, Body Composition Analysis and Quality of Nutrition

Many vegetarians are motivated by the health aspect of starting a plant-based diet. This diet can offer many health benefits. The study aimed to check whether people on a vegetarian diet are in good health, have a good nutritional intake, and follow the principles of healthy eating compared with omnivores. Twenty-two vegetarians on a vegetarian diet for more than five years and 22 omnivores aged 18-45 were interviewed. Each of them was given a food questionnaire, body composition analysis (BIA), and biochemical blood analysis, and their 7-day diet was analyzed. Polish vegetarians exhibit similar health statuses and tend towards better health than omnivores. They have an adequate body composition. Biochemical blood analysis showed no significant differences in blood parameters between vegetarians and omnivores, despite specific deficiencies such as vitamin B₁₂, vitamin D and elevated homocysteine levels in vegetarians. They have a better nutritional status and follow good dietary principles. However, they were more likely to consume alcohol, add salt to their meals and sweeten hot drinks. In addition, the lifestyle of vegetarians can be described as healthier, as they are more likely to engage in leisure-time physical activity and get enough sleep.

High Phosphate-Binding Capacity of Oxylanthanum Carbonate with a Low Medication Volume: Comparison with Commercially Available Phosphate Binders

BACKGROUND

A key focus for chronic kidney disease management is phosphate control, but currently available binders have suboptimal phosphate-binding capacity, and their characteristics result in low adherence and poor phosphate regulation. Oxylanthanum carbonate, a novel compound that uses proprietary nanoparticle technology to deliver lanthanum, has the potential to combine high phosphate-binding capacity with good intake convenience, thus improving adherence and patient quality of life. The goal of this study was to assess the volume of oxylanthanum Carbonate required to bind 1 g of phosphate and compare it with other currently available phosphate binders to determine which binder allows for the highest normalized potency with the lowest daily medication volume.

METHODS

Six phosphate binders were assessed: ferric citrate, calcium acetate, lanthanum carbonate, sevelamer carbonate, sucroferric oxyhydroxide, and oxylanthanum carbonate. Table volume measurements were taken using fluid displacement in corn oil or water. Mean daily dose volume to bind 1 g of phosphate was calculated as volume per tablet multiplied by the mean number of tablets taken per day. Volume to bind 1 g of phosphate was calculated by dividing the volume per tablet by its in vivo binding capacity.

RESULTS

Oxylanthanum carbonate had the lowest mean volume, daily phosphate binder dose volume, and equivalent phosphate-binding dose volume (volume to bind 1 g of phosphate for each binder).

CONCLUSIONS

Oxylanthanum carbonate has the lowest daily phosphate binder dose volume and the smallest volume required to bind 1 g of phosphate compared to all other commercially available phosphate binders. A randomized trial that compares gastrointestinal tolerability across binders would be warranted to demonstrate acceptability and adherence in the target population.

Association of Early Serum Phosphate Levels and Mortality in Patients with Sepsis

BACKGROUND

Metabolic derangements in sepsis influence phosphate levels, which may predict mortality outcomes. We investigated the association between initial phosphate levels and 28-day mortality in patients with sepsis.

METHODS

We conducted a retrospective analysis of patients with sepsis. Initial (first 24 hours) phosphate levels were divided into phosphate quartile groups for comparisons. We used repeated-measures mixed-models to assess differences in 28-day mortality across the phosphate groups, adjusting for other predictors identified by the Least Absolute Shrinkage and Selection Operator variable selection technique.

RESULTS

A total of 1,855 patients were included with 13% overall 28-day mortality (n=237). The highest phosphate quartile (>4.0 milligrams per deciliter [mg/dL]) had a higher mortality rate (28%) than the three lower quartiles (P<0.001). After adjustment (age, organ failure, vasopressor administration, liver disease), the highest initial phosphate was associated with increased odds of 28-day mortality. Patients in the highest phosphate quartile had 2.4 times higher odds of death than the lowest (≤2.6 mg/dL) quartile (P<0.01), 2.6 times higher than the second (2.6-3.2 mg/dL) quartile (P<0.01), and 2.0 times higher than the third (3.2-4.0 mg/dL) quartile (P=0.04).

CONCLUSION

Septic patients with the highest phosphate levels had increased odds of mortality. Hyperphosphatemia may be an early indicator of disease severity and risk of adverse outcomes from sepsis.

Bone fragility during the COVID-19 pandemic: the role of macro- and micronutrients

Bone fragility is the susceptibility to fracture due to poor bone strength. This condition is usually associated with aging, comorbidities, disability, poor quality of life, and increased mortality. International guidelines for the management of patients with bone fragility include a nutritional approach, mainly aiming at optimal protein, calcium, and vitamin D intakes. Several biomechanical features of the skeleton, such as bone mineral density (BMD), trabecular and cortical microarchitecture, seem to be positively influenced by micro- and macronutrient intake. Patients with major fragility fractures are usually poor consumers of dairy products, fruit, and vegetables as well as of nutrients modulating gut microbiota. The COVID-19 pandemic has further aggravated the health status of patients with skeletal fragility, also in terms of unhealthy dietary patterns that might adversely affect bone health. In this narrative review, we discuss the role of macro- and micronutrients in patients with bone fragility during the COVID-19 pandemic.

Protein-Bound Uremic Toxins Lowering Effect of Sevelamer in Pre-Dialysis Chronic Kidney Disease Patients with Hyperphosphatemia: A Randomized Controlled Trial

P-cresyl sulfate and indoxyl sulfate are strongly associated with cardiovascular events and all-cause mortality in chronic kidney disease (CKD). This randomized controlled trial was conducted to compare the effects between sevelamer and calcium carbonate on protein-bound uremic toxins in pre-dialysis CKD patients with hyperphosphatemia. Forty pre-dialysis CKD patients with persistent hyperphosphatemia were randomly assigned to receive either 2400 mg of sevelamer daily or 1500 mg of calcium carbonate daily for 24 weeks. A significant decrease of total serum p-cresyl sulfate was observed in sevelamer therapy compared to calcium carbonate therapy (mean difference between two groups −5.61 mg/L; 95% CI −11.01 to −0.27 mg/L; p = 0.04). There was no significant difference in serum indoxyl sulfate levels (p = 0.36). Sevelamer had effects in terms of lowering fibroblast growth factor 23 (p = 0.01) and low-density lipoprotein cholesterol levels (p = 0.04). Sevelamer showed benefits in terms of retarding CKD progression. Changes in vascular stiffness were not found in this study.

Efficacy of continuous ambulatory peritoneal dialysis combined with hemodialysis versus single hemodialysis in patients with end-stage renal disease

OBJECTIVE

This study aimed to compare the efficacy of single hemodialysis (HD) and continuous ambulatory peritoneal dialysis (CAPD) combined with HD in the treatment of end-stage renal disease.

METHODS

Seventy patients with end-stage renal disease in our hospital from January 2019 to December 2020 were included and divided into 35 patients in the single group (SG) and 35 patients in the combination group (CG) according to a random number table. The SG received HD treatment and the CG received CAPD combined with HD treatment.

RESULTS

Hemoglobin and serum albumin levels were higher, blood urea nitrogen (BUN) and serum creatinine (Scr) levels were lower, and interleukin-6 (IL-6), C-reactive protein (CRP), and tumor necrosis factor-α (TNF-α) levels were lower in the CG than in SG at the end of treatment (P < 0.05). Ca²⁺ levels were higher and P³⁺ levels were decreased at the end of treatment in both groups compared with those before treatment (P < 0.05), and Ca²⁺ and P³⁺ levels at the end of treatment in the CG were not different from those in the SG (P > 0.05). The complication rate in the CG was 5.71%, which was lower than 25.71% in the SG (P < 0.05). Quality of life scores were higher in the CG than in the SG at the end of treatment (P < 0.05).

CONCLUSION

CAPD combined with HD can improve renal function and nutritional levels more significantly, control inflammatory responses more effectively, and reduce complications compared to single HD treatment in patients with end-stage renal disease.

Ophiocordyceps lanpingensis polysaccharides alleviate chronic kidney disease through MAPK/NF-κB pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Ophiocordyceps lanpingensis (O. lanpingensis) is a traditional ethno-medicine distributed in Eastern Himalayas, which has been used by local minorities to prevent and treat urinary diseases for hundreds of years. However, the corresponding active components and related pharmacological mechanism of such medication are not clear yet.

AIMS OF THE STUDY

This study was performed to investigate the effects and potential mechanisms of O. lanpingensis polysaccharides (OLP) in the treatment of chronic kidney disease (CKD) based on our previous research results.

MATERIALS AND METHODS

Methylation analysis was used to investigate the monosaccharide composition and glycosidic linkages in OLP. The animals were divided into the control group, CKD model group, losartan group and three different doses of OLP groups. The CKD mouse model was established by the adenine gavage. The histological changes of renal tissue were observed by Hematoxylin-eosin and Masson staining. Biochemical indicators, including blood urea nitrogen (BUN), serum creatinine (Scr), serum phosphorus (P), plasma calcium (Ca), reactive oxygen species (ROS), superoxide dismutase (SOD), glutathione peroxidase (GSH-PX) and malondialdehyde (MDA) were measured to evaluate the alleviation of CKD by OLP. Moreover, the expression levels of a series of cytokines related to the inflammation, apoptosis and fibrosis were analyzed to explore the possible mechanisms of OLP to treat CKD.

RESULTS

OLP is composed of three kinds of monosaccharides. There are eight kinds of glycosidic linkages in OLP, among which →4)-Glcp-(1→ is the main linkage. OLP could significantly attenuate CKD in mice and the tubulointerstitial damage was recovered to almost normal after the treatment of OLP. Compared with the CKD model group, the levels of Scr, BUN, MDA, P in OLP treatment groups were significantly decreased; and the levels of SOD and Ca were increased after OLP treatment. Furthermore, OLP could reduce the oxidative stress of the renal tissues, decrease the expression levels of pro-inflammatory factors through TLR4-mediated MAPK and NF-κB pathway, inhibit the apoptosis of renal cells by MAPK pathway, and relieve the renal fibrosis by down-regulating the expression of TGF-β1.

CONCLUSIONS

OLP is composed of three kinds of monosaccharides and →4)-Glcp-(1→ is the main glycosidic linkage in the polysaccharide. OLP could ameliorate CKD in mice by declining the oxidative stress, inflammation, apoptosis and fibrosis in the kidneys. The study provided some evidences for the potential application of OLP in alleviating CKD.

Phosphate Control: The Next Frontier in Dialysis Cardiovascular Mortality

BACKGROUND

Cardiovascular disease (CVD) is a major cause of death in patients with chronic kidney disease (CKD) on dialysis. Mortality rates are still unacceptably high even though they have fallen in the past 2 decades. Hyperphosphatemia (elevated serum phosphate levels) is seen in almost all patients with advanced CKD and is by far the largest remaining modifiable contributor to CKD mortality.

SUMMARY

Phosphate retention drives multiple physiological mechanisms linked to increased risk of CVD. Fibroblast growth factor 23 and parathyroid hormone (PTH) levels, both of which have been suggested to have direct pathogenic CV effects, increase in response to phosphate retention. Phosphate, calcium, and PTH levels are linked in a progressively worsening cycle. Maladaptive upregulation of phosphate absorption is also likely to occur further exacerbating hyperphosphatemia. Even higher phosphate levels within the normal range may be a risk factor for vascular calcification and, thus, CV morbidity and mortality. A greater degree of phosphate control is important to reduce the risk of CV morbidity and mortality. Improved phosphate control and regular monitoring of phosphate levels are guideline-recommended, established clinical practices. There are several challenges with the current phosphate management approaches in patients with CKD on dialysis. Dietary restriction of phosphate and thrice-weekly dialysis alone are insufficient/unreliable to reduce phosphate to <5.5 mg/dL. Even with the addition of phosphate binders, the only pharmacological treatment currently indicated for hyperphosphatemia, the majority of patients are unable to achieve and maintain phosphate levels <5.5 mg/dL (or more normal levels) [PhosLo® gelcaps (calcium acetate): 667 mg (prescribing information), 2011, VELPHORO®: (Sucroferric oxyhydroxide) (prescribing information), 2013, FOSRENAL®: (Lanthanum carbonate) (prescribing information), 2016, AURYXIA®: (Ferric citrate) tablets (prescribing information), 2017, RENVELA®: (Sevelamer carbonate) (prescribing information), 2020, RealWorld dynamix. Dialysis US: Spherix Global Insights, 2019]. Phosphate binders do not target the primary pathway of phosphate absorption (paracellular), have limited binding capacity, and bind nonspecifically [PhosLo® gelcaps (calcium acetate): 667 mg (prescribing information). 2013, VELPHORO®: (Sucroferric oxyhydroxide) (prescribing information), 2013, FOSRENAL®: (Lanthanum carbonate) (prescribing information), 2016, AURYXIA®: (Ferric citrate) tablets (prescribing information), 2017, RENVELA®: (Sevelamer carbonate) (prescribing information) 2020]. Key Messages: Despite current phosphate management strategies, most patients on dialysis are unable to consistently achieve target phosphate levels, indicating a need for therapeutic innovations [RealWorld dynamix. Dialysis US: Spherix Global Insights, 2019]. Given a growing evidence base that the dominant mechanism of phosphate absorption is the intestinal paracellular pathway, new therapies are investigating ways to reduce phosphate levels by blocking absorption through the paracellular pathway.

Prediction of 72-hour mortality in patients with extremely high serum C-reactive protein levels using a novel weighted average of risk scores

The risk factors associated with mortality in patients with extremely high serum C-reactive protein (CRP) levels are controversial. In this retrospective single-center cross-sectional study, the clinical and laboratory data of patients with CRP levels ≥40 mg/dL treated in Saitama Medical Center, Japan from 2004 to 2017 were retrieved from medical records. The primary outcome was defined as 72-hour mortality after the final CRP test. Forty-four mortal cases were identified from the 275 enrolled cases. Multivariate logistic regression analysis (MLRA) was performed to explore the parameters relevant for predicting mortality. As an alternative method of prediction, we devised a novel risk predictor, “weighted average of risk scores” (WARS). WARS features the following: (1) selection of candidate risk variables for 72-hour mortality by univariate analyses, (2) determination of C-statistics and cutoff value for each variable in predicting mortality, (3) 0–1 scoring of each risk variable at the cutoff value, and (4) calculation of WARS by weighted addition of the scores with weights assigned according to the C-statistic of each variable. MLRA revealed four risk variables associated with 72-hour mortality—age, albumin, inorganic phosphate, and cardiovascular disease—with a predictability of 0.829 in C-statistics. However, validation by repeated resampling of the 275 records showed that a set of predictive variables selected by MLRA fluctuated occasionally because of the presence of closely associated risk variables and missing data regarding some variables. WARS attained a comparable level of predictability (0.837) by combining the scores for 10 risk variables, including age, albumin, electrolytes, urea, lactate dehydrogenase, and fibrinogen. Several mutually related risk variables are relevant in predicting 72-hour mortality in patients with extremely high CRP levels. Compared to conventional MLRA, WARS exhibited a favorable performance with flexible coverage of many risk variables while allowing for missing data.

Metabonomic analysis of hypophosphatemic laying fatigue syndrome in laying hens

Laying fatigue syndrome (LFS) is a common disease in poultry, which is characterized by low egg laying rate, increased broken and soft shell egg rate and osteoporosis, and even death of poultry. Insufficient phosphorus content in feed is one of the major causes of LFS. In this study, a total of 22-week-old Roman white shell hens were randomly divided into two groups, including control (group C) and low dietary phosphorus (group P) groups. The hens of groups C and P were fed with a full mixed diet and a mixed diet containing 0.18% available phosphorus content, respectively. At 25, 29 and 34 weeks, the production performance of hens was detected and the serum samples of hens were collected to detect the changes of serum phosphorus, calcium, osteopelectin (OPG), parathyroid hormone (PTH), estradiol (E₂), tartaric acid-resistant phosphatase (TRACP) and alkaline phosphatase (ALP). The keels were removed and x-rayed. In addition, all serum samples were tested by LC-MS metabolomics. Our results showed that low dietary phosphorus decreased the production performance, phosphorus content, and E₂ and OPG levels, while increased calcium and PTH levels, and ALP and TRACP activities in laying hens. The hens of group P had bent keels. Besides, small molecular metabolites in serum were enriched in 10 pathways and 17 metabolites were significantly different according to the area under the receiver operating characteristic curve (AUC) analysis. Our results showed that low phosphorus diet could induce LFS. Also, 17 metabolites detected by metabonomics can be used as biomarkers for clinical diagnosis and early warning of hypophosphatemic laying fatigue syndrome (HLFS). This study provides a scientific basis for the early prevention and treatment of HLFS.

DAXX mediates high phosphate-induced endothelial cell apoptosis in vitro through activating ERK signaling

BACKGROUD AND PURPOSE

Hyperphosphatemia, which is a high inorganic phosphate (Pi) level in the serum, promotes endothelial cells dysfunction and is associated with cardiovascular diseases in patients with chronic kidney diseases (CKD). However, the underlying mechanism of high Pi-induced endothelia cell apoptosis remains unclear.

METHODS

Human umbilical vein endothelial cells (HUVECs) were treated with normal Pi (1.0 mM) and high Pi (3.0 mM), and then cell apoptosis, abnormal gene expression and potential signaling pathway involvement in simulated hyperphosphatemia were examined using flow cytometry, quantitative PCR (qPCR) and western blot analysis. A two-step 5/6 nephrectomy was carried out to induce CKD and biochemical measurements were taken.

RESULTS

The rat model of CKD revealed that hyperphosphatemia is correlated with an increased death-domain associated protein (DAXX) expression in endothelial cells. In vitro, high Pi increased the mRNA and protein expression level of DAXX in HUVECs, effects that were reversed by additional phosphonoformic acid treatment. Functionally, high Pi resulted in a significantly increased apoptosis in HUVECs, whereas DAXX knockdown markedly repressed high Pi-induced cell apoptosis, indicating that DAXX mediated high Pi-induced endothelial cell apoptosis. High Pi treatment and DAXX overexpression induced the activation of extracellular regulated protein kinases (ERKs), while DAXX knockdown inhibited high Pi-induced ERKs activation. Finally, we demonstrated that DAXX overexpression induced HUVECs apoptosis in the presence of normal Pi, whereas additional treatment with U0126 (a specific ERK inhibitor) reversed that effect.

CONCLUSION

Upregulated DAXX promoted high Pi-induced HUVECs apoptosis by activating ERK signaling and indicated that the DAXX/ERK signaling axis may be served as a potential target for CKD therapy.

Can Helicobacter pylori Colonization Affect the Phosphate Binder Pill Burden in Dialysis Patients?

Phosphate binder pill (PBP) burden is a significant problem in dialysis patients. Phosphate absorption through the paracellular pathway increases in relatively acidic pH. In this study, we evaluated the effect of factors contributing to duodenal pH-Helicobacter pylori (HP), proton pump inhibitors (PPIs), and NaHCO₃ capsules-on PBP burden. We evaluated 255 dialysis patients with gastric biopsies and excluded patients with low Kt/V, gastrectomy, and parathyroidectomy. Patients were divided into groups and subgroups regarding HP existence, use of PPI, or NaHCO₃ capsules. HP+ group had significantly higher PBP burden and PBP equivalent doses (P < 0.001; both). HP+ subgroup not using daily PPIs or NaHCO₃ capsules had the highest PBP burden and PBP equivalent doses (P < 0.001; both). HP- subgroups had similar PBP and PBP equivalent doses (P = 0.446 and P = 0.382; respectively). HP colonization might affect the PBP burden in dialysis patients due to a decrease of duodenal pH.

Recirculating peritoneal dialysis system using urease-fixed silk fibroin membrane filter with spherical carbonaceous adsorbent

The chronic kidney disease (CKD) patients are undergoing continuous ambulatory peritoneal dialysis (CAPD). However, there are some constraints, the frequent exchange of the dialysate and limitation of outside activity, associated with CAPD remain to be solved. In this study, we designed the wearable artificial kidney (WAK) system for peritoneal dialysis (PD) using urease-immobilized silk fibroin (SF) membrane and polymer-based spherical carbonaceous adsorbent (PSCA). We evaluated this kit's removal abilities of uremic toxins such as urea, creatinine, uric acid, phosphorus, and β2-microglobulin from the dialysate of end-stage renal disease (ESRD) patients in vitro. The uremic toxins including urea, creatinine, uric acid, and phosphorus were removed about 99% by immobilized SF membrane and PSCA filter after 24 h treatment. However, only 50% of β2-microglobulin was removed by this filtering system after 24 h treatment. In vivo study result shows that our filtering system has more uremic toxins removal efficiency than exchanged dialysate at every 6 h. We suggest that recirculating PD system using urease-immobilized SF membrane with PSCA could be more efficient than traditional dialysate exchange system for a WAK for PD.

Hypophosphatemia in the setting of metabolic bone disease: case reports and diagnostic algorithm

Osteoporosis is the most commonly encountered metabolic bone disease, and metabolic bone-disease clinics have been established to assist in the diagnosis and treatment of uncommon causes of low bone-mineral density. Hypophosphatemia leading to metabolic bone disease may be encountered, and an understanding of phosphate homeostasis can aid in the diagnosis. Two cases of hypophosphatemia leading to low bone-mineral densities were seen at the University of Alabama at Birmingham Osteoporosis Clinic. We developed a diagnostic algorithm, and the laboratory values of each patient were tested with the algorithm. The algorithm, incorporating the use of a spot urine phosphate and spot urine creatinine level at the time of initial serum metabolic profile evaluation, accurately determined the cause of hypophosphatemia in each case.

Exploring the Link between Serum Phosphate Levels and Low Muscle Strength, Dynapenia, and Sarcopenia

Emerging evidences addressed an association between phosphate and muscle function. Because little attention was focused on this issue, the objective of our study was to explore the relationship of phosphate with muscle strength, dynapenia, and sarcopenia. From the National Health and Nutrition Examination Survey, a total of 7421 participants aged 20 years or older were included in our study with comprehensive examinations included anthropometric parameters, strength of the quadriceps muscle, and appendicular lean masses. Within the normal range of serum phosphate, we used quartile-based analyses to determine the potential relationships of serum phosphate with dynapenia, and sarcopenia through multivariate regression models. After adjusting for the pertinent variables, an inverse association between the serum phosphate quartiles and muscle strength was observed and the linear association was stronger than other anthropometric parameters. Notably, the significant association between phosphate and muscle strength was existed in >65 years old age group, not in 20-65 years old. The higher quartiles of phosphate had higher likelihood for predicting the presence of dynapenia rather than sarcopenia in entire population. Our study highlighted that higher quartiles of phosphate had significant association with lower muscle strength and higher risks for predicting the presence of dynapenia.

Hyperparathyroidism Caused by Coexisting Parathyroid Hyperplasia and Ectopic Parathyroid Adenomas

Tc sestamibi parathyroid scan was performed in a 35-year-old man with chronic renal failure to evaluate the cause of increased serum parathyroid hormone. Both early and delayed images showed intense activity overlapping the left upper pole of the thyroid, which was proven to be nodular parathyroid hyperplasia after parathyroidectomy. However, the levels of serum parathyroid hormone remained elevated postsurgically. A repeat sestamibi study revealed abnormal activity in the left upper mediastinum, which could also be subtly seen on initial sestamibi study. A retrosternal lesion was resected, which was confirmed as an ectopic parathyroid adenoma by pathological examination.