Therapeutic Effects of Add-On Tenapanor for Hemodialysis Patients with Refractory Hyperphosphatemia

INTRODUCTION

Phosphate binders are used to treat hyperphosphatemia. Some patients have inappropriately controlled serum phosphorus levels, which may occur for many reasons, including a high pill burden and adverse events (AEs). Tenapanor selectively inhibits the passive paracellular transfer of phosphate in the gastrointestinal tract, thereby reducing serum phosphorus levels. This novel mechanism of action may contribute to improved phosphate management. The efficacy and safety of tenapanor have not been evaluated in Japanese patients with high serum phosphorus levels despite treatment with phosphate binders. This study aimed to assess the efficacy and safety of add-on tenapanor therapy for reducing serum phosphorus levels in this population.

METHODS

This multicenter, double-blind, randomized, placebo-controlled trial enrolled patients with refractory hyperphosphatemia undergoing hemodialysis. Patients were randomly assigned in a 1:1 ratio to receive tenapanor or placebo as an add-on to their phosphate binder regimen for 6 weeks. Change in serum phosphorus levels at week 6 (day 43) compared with the baseline value (day 1, week 0) (primary endpoint), achievement of target serum phosphorus levels (serum phosphorus level ≤6.0 or ≤5.5 mg/dL), and safety, based on all AEs and drug-related AEs, were among the outcomes evaluated.

RESULTS

In total, 24 patients were randomly assigned to the placebo group and 23 to the tenapanor group. The mean serum phosphorus level decreased from 7.01 mg/dL on day 1 to 6.69 mg/dL on day 43 in the placebo group and from 6.77 mg/dL on day 1 to 4.67 mg/dL on day 43 in the tenapanor group. In the placebo and tenapanor groups (modified intent-to-treat population), the mean (standard deviation) change in the serum phosphorus level at day 43 (last observation carried forward [LOCF]) was 0.08 (1.52) mg/dL and -1.99 (1.24) mg/dL, respectively, with a between-group difference of -2.07 (95% confidence interval: -2.89, -1.26; p < 0.001). The target achievement rate (serum phosphorus level ≤6.0 mg/dL at week 6 [LOCF]) was 37.5 and 87.0% in the placebo and tenapanor groups, respectively. Diarrhea was the most common drug-related AE, and it occurred in 8.3 and 65.2% of patients in the placebo and tenapanor groups, respectively. No specific AEs were observed with add-on tenapanor or with phosphate binders.

DISCUSSION/CONCLUSION

Therapy with existing phosphate binders and add-on tenapanor resulted in a significant decrease in serum phosphorus level compared with the placebo group in patients with refractory hyperphosphatemia despite treatment with phosphate binders. No new safety signals were raised, and add-on tenapanor was generally well tolerated.

The Importance of Phosphate Control in Chronic Kidney Disease

A series of problems including osteopathy, abnormal serum data, and vascular calcification associated with chronic kidney disease (CKD) are now collectively called CKD-mineral bone disease (CKD-MBD). The pathophysiology of CKD-MBD is becoming clear with the emerging of αKlotho, originally identified as a progeria-causing protein, and bone-derived phosphaturic fibroblast growth factor 23 (FGF23) as associated factors. Meanwhile, compared with calcium and parathyroid hormone, which have long been linked with CKD-MBD, phosphate is now attracting more attention because of its association with complications and outcomes. Incidentally, as the pivotal roles of FGF23 and αKlotho in phosphate metabolism have been unveiled, how phosphate metabolism and hyperphosphatemia are involved in CKD-MBD and how they can be clinically treated have become of great interest. Thus, the aim of this review is reconsider CKD-MBD from the viewpoint of phosphorus, its involvement in the pathophysiology, causing complications, therapeutic approach based on the clinical evidence, and clarifying the importance of phosphorus management.

The effects of L-carnitine on renal function and gene expression of caspase-9 and Bcl-2 in monosodium glutamate-induced rats

BACKGROUND

Monosodium glutamate (MSG) is frequently consumed as a flavor enhancer or food additive. Possible damages induced by MSG effects on some organs have been stated in experimental animal models. The aim of the present study was to evaluate the protective effects of L-carnitine (L-ca) on the renal tissue in MSG-Induced Rats.

METHODS

In this regard, 60 male rats were randomly divided into six groups (n = 10/each): 1 (Control); 2 (sham); 3 (L-carnitine 200 mg/kg b.w); 4 (MSG 3 g/kg b.w); 5 (MSG + L-carnitine 100 mg/kg); and 6 (MSG + L-carnitine 200 mg/kg). After 6 months, the rats were sacrificed, the blood sample collected and the kidneys harvested for evaluation of biochemical analytes, genes expression, and histopathological changes.

RESULTS

MSG significantly increased the serum level of MDA, BUN, creatinine, uric acid and renal Caspase-9, NGAL and KIM-1 expression, but it decreased the serum activity also renal expression of SOD, catalase, GPX, and Bcl-2 expression compared to the control group. Treatment with L-ca significantly reduced the serum BUN, creatinine, uric acid and MDA level and increased catalase, GPX and SOD compared to the MSG group. However, only administration of L-ca 200 significantly decreased the caspase-9, NGAL and KIM-1; also, it increased the Bcl-2 expression in the kidney compared to the MSG group.

CONCLUSIONS

Our findings indicated that L-carnitine had a major impact on the cell protection and might be an effective therapy in ameliorating the complications of the kidney induced by MSG via its antioxidant and anti-apoptotic properties.

Pharmacokinetics and safety of TCMCB07, a melanocortin-4 antagonist peptide in dogs

The melanocortin-4 receptor (MC4R) antagonistic peptide TCMCB07 was developed for the treatment of cachexia. The objectives of this study were to examine pharmacokinetics and safety of TCMCB07 administered subcutaneously to healthy dogs. Dogs were treated with high- (2.25 mg kg-1 ) (n = 5) and low-dose TCMCB07 (0.75 mg kg-1 ) (n = 5) once daily for 28 days with a 14-day washout period between groups. Histamine levels, complete blood count, chemistry panel, blood pressure, 24-hour Holter recording, and pharmacokinetic parameters were monitored in the high-dose group. Physical examination changes were limited to weight gain and darkening of the coat color. There was no elevation of plasma histamine within 24 hours of injection but there was a significant elevation of plasma histamine across time. An approximately doubled eosinophil count and an approximately 25% increase, and then 25% decrease back to pre-treatment plasma phosphorous were also found, although both remained within the reference interval. Serial blood pressure and 24-hour Holter monitors revealed no clinically relevant changes. A difference was found in the AUC between dosing groups and a significant effect of dose, time, and interaction was noted for Vd . Low-dose TCMCB07 had a Cmax of 2.1 ug ml-1 at day 28, compared to high-dose TCMCB07 which had a Cmax 3.6 ug ml-1 at day 28. Once-daily subcutaneous administration of TCMCB07 was well-tolerated for up to 28 days in dogs when administered at doses one and three times (0.75 mg kg-1 and 2.25 mg kg-1 ) the predicted therapeutic dose and pharmacokinetic parameters are described. SIGNIFICANCE STATEMENT: Melanocortin-4 receptor (MC4R) antagonistic peptide TCMCB07 is safe at both low and high doses in dogs. Therapy was tolerated well as determined by physical examination, clinical pathology, and cardiovascular parameters; darkening of the coat was noted with treatment and resolved with discontinuation. Pharmacokinetics are described and further study in the naturally occurring canine model is warranted.

Incidence rate of vitamin D deficiency and FGF23 levels in 12- to 13-year-old adolescents in Japan

INTRODUCTION

The incidence rate of vitamin D deficiency is increasing throughout the world. We measured the incidence rate of vitamin D deficiency and fibroblast growth factor 23 (FGF23) levels in 12- to 13-year-old adolescents in Japan.

MATERIALS AND METHODS

A total of 492 adolescents (247 boys and 245 girls) from Japanese community enrolled in this study. 25 hydroxyvitamin D (25(OH)D) was measured with radioimmunoassay. In the subjects with low 25(OH)D levels (≦ 20 ng/ml), intact parathyroid hormone (iPTH), calcium (Ca), phosphorus (P), albumin (Alb), alkaline phosphatase (ALP) and FGF23 were measured.

RESULTS

25(OH)D levels were significantly lower in girls (20.9 ± 3.1 ng/ml) than in boys (22.2 ± 3.3 ng/ml) (p < 0.0001). Fifty-five boys (22.3%) and 83 (33.9%) girls showed vitamin D deficiency (< 20 ng/ml). One-hundred eighty-six (75.3%) boys and 162 (66.1%) girls showed vitamin D insufficiency (≧ 20 ng/ml, < 30 ng/ml). In the subjects whose 25(OH)D levels were ≦ 20 ng/ml, the levels of iPTH, Ca, P, Alb, ALP and FGF23 were 22.3 ± 9.0 pg/ml, 9.5 ± 0.4 mg/dl, 4.7 ± 0.6 mg/dl, 4.6 ± 0.3 g/dl, 920.8 ± 339.3 U/l and 42.6 ± 26.0 pg/ml, respectively. There was a significant negative association between serum 25(OH)D levels and iPTH [r =  - 0.290 (p < 0.0001)]. There was no significant association between serum 25(OH)D levels and FGF23.

CONCLUSION

We show that 28% of Japanese 12- to 13-year-old early adolescents suffer from vitamin D deficiency. Findings from this study indicate that vitamin D deficiency requires close oversight in public health during adolescence to ensure proper bone health.

Spectroscopic Signature of Red Blood Cells in a D-Galactose-Induced Accelerated Aging Model

This work presents a semi-quantitative spectroscopic approach, including FTIR-ATR and Raman spectroscopies, for the biochemical analysis of red blood cells (RBCs) supported by the biochemical, morphological and rheological reference techniques. This multi-modal approach provided the description of the RBC alterations at the molecular level in a model of accelerated aging induced by administration of D-galactose (D-gal), in comparison to natural aging. Such an approach allowed to conclude that most age-related biochemical RBC membrane changes (a decrease in lipid unsaturation and the level of phospholipids, or an increase in acyl chain shortening) as well as alterations in the morphological parameters and RBC deformability are well reflected in the D-gal model of accelerated aging. Similarly, as in natural aging, a decrease in LDL level in blood plasma and no changes in the fraction of glucose, creatinine, total cholesterol, HDL, iron, or triglycerides were observed during the course of accelerated aging. Contrary to natural aging, the D-gal model led to an increase in cholesterol esters and the fraction of total esterified lipids in RBC membranes, and evoked significant changes in the secondary structure of the membrane proteins. Moreover, a significant decrease in the phosphorous level of blood plasma was specific for the D-gal model. On the other hand, natural aging induced stronger changes in the secondary structures of the proteins of the RBCs' interior. This work proves that research on the aging mechanism, especially in circulation-related diseases, should employ the D-gal model with caution. Nonetheless, the D-gal model enables to imitate age-related rheological alterations in RBCs, although they are partially derived from different changes observed in the RBC membrane at the molecular level.

Dietary Phosphorus as a Marker of Mineral Metabolism and Progression of Diabetic Kidney Disease

Phosphorus is an essential nutrient that is critically important in the control of cell and tissue function and body homeostasis. Phosphorus excess may result in severe adverse medical consequences. The most apparent is an impact on cardiovascular (CV) disease, mainly through the ability of phosphate to change the phenotype of vascular smooth muscle cells and its contribution to pathologic vascular, valvular and other soft tissue calcification. Chronic kidney disease (CKD) is the most prevalent chronic disease manifesting with the persistent derangement of phosphate homeostasis. Diabetes and resulting diabetic kidney disease (DKD) remain the leading causes of CKD and end-stage kidney disease (ESRD) worldwide. Mineral and bone disorders of CKD (CKD-MBD), profound derangement of mineral metabolism, develop in the course of the disease and adversely impact on bone health and the CV system. In this review we aimed to discuss the data concerning CKD-MBD in patients with diabetes and to analyze the possible link between hyperphosphatemia, certain biomarkers of CKD-MBD and high dietary phosphate intake on prognosis in patients with diabetes and DKD. We also attempted to clarify if hyperphosphatemia and high phosphorus intake may impact the onset and progression of DKD. Careful analysis of the available literature brings us to the conclusion that, as for today, no clear recommendations based on the firm clinical data can be provided in terms of phosphorus intake aiming to prevent the incidence or progression of diabetic kidney disease.

Genetically predicted circulating concentrations of micronutrients and risk of breast cancer: A Mendelian randomization study

The epidemiological literature reports inconsistent associations between consumption or circulating concentrations of micronutrients and breast cancer risk. We investigated associations between genetically predicted concentrations of 11 micronutrients (beta-carotene, calcium, copper, folate, iron, magnesium, phosphorus, selenium, vitamin B6 , vitamin B12 and zinc) and breast cancer risk using Mendelian randomization (MR). A two-sample MR study was conducted using 122 977 women with breast cancer and 105 974 controls from the Breast Cancer Association Consortium. MR analyses were conducted using the inverse variance-weighted approach, and sensitivity analyses were conducted to assess the impact of potential violations of MR assumptions. A value of 1 SD (SD: 0.08 mmol/L) higher genetically predicted concentration of magnesium was associated with a 17% (odds ratio [OR]: 1.17, 95% confidence interval [CI]: 1.10-1.25, P value = 9.1 × 10-7 ) and 20% (OR: 1.20, 95% CI: 1.08-1.34, P value = 3.2 × 10-6 ) higher risk of overall and ER+ve breast cancer, respectively. An inverse association was observed for a SD (0.5 mg/dL) higher genetically predicted phosphorus concentration and ER-ve breast cancer (OR: 0.84, 95% CI: 0.72-0.98, P value = .03). There was little evidence that any other nutrient was associated with breast cancer. The results for magnesium were robust under all sensitivity analyses and survived correction for multiple comparisons. Higher circulating concentrations of magnesium and potentially phosphorus may affect breast cancer risk. Further work is required to replicate these findings and investigate underlying mechanisms.

Effects of repeated increasing doses of cisplatin as models of acute kidney injury and chronic kidney disease in rats

Cisplatin (CP) is nephrotoxic, and this side effect is used as an animal model for acute kidney injury (AKI). Earlier research has been focused on CP-induced AKI, with relatively little attention being paid to its ability to progress to chronic kidney disease (CKD) on repeated administration. We aimed here to test the dose dependency of its nephrotoxic actions by comparing various physiological, biochemical, molecular, and histopathological indices using repeated increasing doses of CP in rats. Furthermore, we investigated whether these doses of CP would result in the development of CKD. Biochemical, molecular, and histopathological measurements were conducted in plasma, urine, and/or kidneys of rats treated with increasing doses of CP at 1.6, 3.2, and 4.8 mg kg-1 weekly for four consecutive weeks. These doses induced significant and dose-dependent elevations in most of the measured renal indices. These included increased renal fibrosis, as suggested histopathologically and biochemically by the significant increase in transforming growth factor-β1, significant decrease in actin alpha 2, and variable actions of collagen I and IV. CP also dose-dependently increased nuclear factor (erythroid-derived 2)-like 2 and caspase-3. Multiple repeated doses of CP (1.6 to 4.8 mg kg-1) induced multiple episodes of AKI, leading to CKD after the 4th weekly dose and confirmed that this dosage regimen could be used as an experimental animal model of AKI progressing to CKD. These actions were driven by inflammation, oxidative, and nitrosative stress.

Micronutrients in Multiple Pregnancies-The Knowns and Unknowns: A Systematic Review

Maternal diet and nutritional status are of key importance with regard to the short- and long-term health outcomes of both the mother and the fetus. Multiple pregnancies are a special phenomenon in the context of nutrition. The presence of more than one fetus may lead to increased metabolic requirements and a faster depletion of maternal macro- and micro- nutrient reserves than in a singleton pregnancy. The aim of this systematic review was to gather available knowledge on the supply and needs of mothers with multiple pregnancies in terms of micronutrients and the epidemiology of deficiencies in that population. It was constructed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses Statement (PRISMA). The authors conducted a systematic literature search with the use of three databases: PubMed/MEDLINE, Scopus and Embase. The last search was run on the 18 October 2020 and identified 1379 articles. Finally, 12 articles and 1 series of publications met the inclusion criteria. Based on the retrieved studies, it may be concluded that women with multiple pregnancies might be at risk of vitamin D and iron deficiencies. With regard to other microelements, the evidence is either inconsistent, scarce or absent. Further in-depth prospective and population studies are necessary to determine if nutritional recommendations addressed to pregnant women require adjustments in cases of multiple gestations.

Parathyroid Changes After RAI in Patients With Differentiated Thyroid Carcinoma

OBJECTIVE

The purpose of this study was to investigate parathyroid hormone (PTH), serum calcium, phosphorus, and 25-hydroxyvitamin D (25-OH-VD) changes before and after radioactive iodine (RAI) in differentiated thyroid carcinoma (DTC) patients at different time points.

METHODS

A total of 259 DTC patients who received RAI were prospectively enrolled. We evaluated PTH, serum calcium, phosphorus, and 25-OH-VD levels at baseline pre-RAI, five days, six weeks, and six months post-RAI, respectively. We analyzed the risk factors of hypocalcemia at five days post-RAI.

RESULTS

The mean PTH, serum calcium and phosphorus values decreased five days post-RAI compared with pre-RAI (PTH 4.18 ± 1.23 pmol/L vs. 3.95 ± 1.41 pmol/L; calcium 2.27 ± 0.09 mmol/L vs. 2.20 ± 0.11 mmol/L; phosphorus 1.25 ± 0.17 vs. 0.98 ± 0.20 mmol/L, P < 0.05), and the differences were statistically significant. The mean 25-OH-VD levels did not significantly decrease at five days post-RAI. 21.2% (55/259) of patients had hypocalcemia at five days post-RAI, and all of them were given oral calcium supplements. At six weeks post-RAI, all of the above parameters were higher than those at five days post-RAI. Multivariate regression analysis showed that baseline pre-RAI serum calcium < 2.27 mmol/L, PTH < 4.18 pmol/L and negative ^99mTcO₄^- thyroid imaging were risk factors for hypocalcemia at five days post-RAI.

CONCLUSION

For DTC patients with normal PTH and serum calcium levels at pre-RAI, their PTH, serum calcium, and phosphorus levels decreased at five days post-RAI. About one-fifth of patients could have hypocalcemia at five days post-RAI. Lower baseline pre-RAI serum calcium and PTH levels and negative ^99mTcO₄^- thyroid imaging were risk factors for hypocalcemia five days post-RAI.

Murine Fetal Serum Phosphorus is Set Independent of FGF23 and PTH, Except in the Presence of Maternal Phosphate Loading

Fibroblast growth factor 23 (FGF23) appears to play no role until after birth, given unaltered phosphate and bone metabolism in Fgf23- and Klotho-null fetuses. However, in those studies maternal serum phosphorus was normal. We studied whether maternal phosphate loading alters fetal serum phosphorus and invokes a fetal FGF23 or parathyroid hormone (PTH) response. C57BL/6 wild-type (WT) female mice received low (0.3%), normal (0.7%), or high (1.65%) phosphate diets beginning 1 week prior to mating to WT males. Fgf23+/- female mice received the normal or high-phosphate diets 1 week before mating to Fgf23+/- males. One day before expected birth, we harvested maternal and fetal blood, intact fetuses, placentas, and fetal kidneys. Increasing phosphate intake in WT resulted in progressively higher maternal serum phosphorus and FGF23 during pregnancy, while PTH remained undetectable. Fetal serum phosphorus was independent of the maternal phosphorus and PTH remained low, but FGF23 showed a small nonsignificant increase with high maternal serum phosphorus. There were no differences in fetal ash weight and mineral content, or placental gene expression. High phosphate intake in Fgf23+/- mice also increased maternal serum phosphorus and FGF23, but there was no change in PTH. WT fetuses remained unaffected by maternal high-phosphate intake, while Fgf23-null fetuses became hyperphosphatemic but had no change in PTH, skeletal ash weight or mineral content. In conclusion, fetal phosphate metabolism is generally regulated independently of maternal serum phosphorus and fetal FGF23 or PTH. However, maternal phosphate loading reveals that fetal FGF23 can defend against the development of fetal hyperphosphatemia.

The risk of medically uncontrolled secondary hyperparathyroidism depends on parathyroid hormone levels at haemodialysis initiation

BACKGROUND

Optimal parathyroid hormone (PTH) control during non-dialysis chronic kidney disease (ND-CKD) might decrease the subsequent risk of parathyroid hyperplasia and uncontrolled secondary hyperparathyroidism (SHPT) on dialysis. However, the evidence for recommending PTH targets and therapeutic strategies is weak for ND-CKD. We evaluated the patient characteristics, treatment patterns and PTH control over the first year of haemodialysis (HD) by PTH prior to HD initiation.

METHODS

We studied 5683 incident HD patients from 21 countries in Dialysis Outcomes and Practice Patterns Study Phases 4-6 (2009-18). We stratified by PTH measured immediately prior to HD initiation and reported the monthly prescription prevalence of active vitamin D and calcimimetics over the first year of HD and risk of PTH >600 pg/mL after 9-12 months on HD.

RESULTS

The 16% of patients with PTH >600 pg/mL prior to HD initiation were more likely to be prescribed active vitamin D and calcimimetics during the first year of HD. The prevalence of PTH >600 pg/mL 9-12 months after start of HD was greater for patients who initiated HD with PTH >600 (29%) versus 150-300 (7%) pg/mL (adjusted risk difference: 19%; 95% confidence interval : 15%, 23%). The patients with sustained PTH >600 pg/mL after 9-12 months on HD were younger, more likely to be black, and had higher serum phosphorus and estimated glomerular filtration rates at HD initiation.

CONCLUSIONS

Increased PTH before HD start predicted a higher PTH level 9-12 months later, despite greater use of active vitamin D and calcimimetics. More targeted PTH control during ND-CKD may influence outcomes during HD, raising the need for PTH target guidelines in these patients.

Renoprotective effects of sucroferric oxyhydroxide in a rat model of chronic renal failure

Introduction

Sucroferric oxyhydroxide (PA21) is an efficacious, well-tolerated iron-based phosphate binder and a promising alternative to existing compounds. We compared the effects of PA21 with those of a conventional phosphate binder on renal function, mineral homeostasis and vascular calcification in a chronic kidney disease–mineral and bone disorder (CKD-MBD) rat model.

Methods

To induce stable renal failure, rats were administered a 0.25% adenine diet for 8 weeks. Concomitantly, rats were treated with vehicle, 2.5 g/kg/day PA21, 5.0 g/kg/day PA21 or 3.0 g/kg/day calcium carbonate (CaCO₃). Renal function and calcium/phosphorus/iron metabolism were evaluated during the study course. Renal fibrosis, inflammation, vascular calcifications and bone histomorphometry were quantified.

Results

Rats treated with 2.5 or 5.0 g/kg/day PA21 showed significantly lower serum creatinine and phosphorus and higher ionized calcium levels after 8 weeks of treatment compared with vehicle-treated rats. The better preserved renal function with PA21 went along with less severe anaemia, which was not observed with CaCO₃. Both PA21 doses, in contrast to CaCO₃, prevented a dramatic increase in fibroblast growth factor (FGF)-23 and significantly reduced the vascular calcium content while both compounds ameliorated CKD-related hyperparathyroid bone.

Conclusions

PA21 treatment prevented an increase in serum FGF-23 and had, aside from its phosphate-lowering capacity, a beneficial impact on renal function decline (as assessed by the renal creatinine clearance) and related disorders. The protective effect of this iron-based phosphate binder on the kidney in rats, together with its low pill burden in humans, led us to investigate its use in patients with impaired renal function not yet on dialysis.

Is vitamin D deficiency a risk factor for COVID-19 in children?

OBJECTIVE

Coronavirus disease 2019 (COVID-19) is a global health problem that can result in serious complications. The aim of this study was to investigate the prevalence and clinical importance of vitamin D deficiency in children with COVID-19.

MATERIAL AND METHODS

This study includes 40 patients who were diagnosed to have COVID-19 and hospitalized with the real-time reverse transcription polymerase chain reaction method, 45 healthy matched control subjects with vitamin D levels. The age of admission, clinical and laboratory data, and 25-hydroxycholecalciferol (25-OHD) levels were recorded. Those with vitamin D levels which are below 20 ng/ml were determined as Group 1 and those with ≥20 ng/ml as Group 2.

RESULTS

Patients with COVID-19 had significantly lower vitamin D levels 13.14 μg/L (4.19-69.28) than did the controls 34.81 (3.8-77.42) μg/L (p < .001). Patients with COVID-19 also had significantly lower serum phosphorus (4.09 ± 0.73 vs. 5.06 ± 0.93 vs. (U/L) (p < .001)) values compared with the controls. The symptom of fever was significantly higher in COVID- 19 patients who had deficient and insufficient vitamin D levels than in patients who had sufficient vitamin D levels (p = .038). There was a negative correlation found between fever symptom and vitamin D level (r = -0.358, p = .023).

CONCLUSION

This is the first to evaluate vitamin D levels and its relationship with clinical findings in pediatric patients with COVID-19. Our results suggest that vitamin D values may be associated with the occurrence and management of the COVID-19 disease by modulating the immunological mechanism to the virus in the pediatric population.

Effect of a maximal exercise test on serum and urinary concentrations of magnesium, phosphorous, rubidium and strontium in athletes

AIM

This study aims to determine the changes induced by a maximal exercise test until exhaustion on the serum and urinary concentrations of Magnesium (Mg), Phosphorous (P), Rubidium (Rb) and Strontium (Sr) in athletes (AG) and sedentary students (SG).

METHODS

Fifty subjects participated in the study divided into two groups. In AG there were twenty-five male athletes and in SG there were twenty-five male sedentary students. Both groups performed an exercise test until exhaustion, starting at 8 or 10 km/h respectively, and increasing the speed at 1 km/h every 400 m. Serum and urine samples were obtained from all participants before and after the test.

RESULTS

Regarding the basal status, AG showed lower values of Mg in serum (p < 0.05) and urine (p < 0.01), but higher concentrations of serum P (p < 0.05) in comparison to SG. Comparing the pre and post-test values, corrected or non-corrected for hemoconcentration in serum and for creatinine in urine, AG showed a decrease in serum Mg (p < 0.05), in serum P (p < 0.01) and in urinary Sr (p < 0.01) while an increase was observed in urinary P (p < 0.05) and in urinary Rb (p < 0.05).

CONCLUSIONS

It can be concluded that a treadmill test until exhaustion leads to changes in serum and urinary concentrations of minerals in both AG and SG males. This may reflect an adaptive response of the body to overcome the physical stress and, in some cases, to avoid loss of these elements.

Serum magnesium, bone-mineral metabolism markers and their interactions with kidney function on subsequent risk of peripheral artery disease: the Atherosclerosis Risk in Communities Study

BACKGROUND

Few studies have investigated the association of magnesium levels with incident peripheral artery disease (PAD) despite emerging evidence of magnesium contributing to vascular calcification. Moreover, no data are available on whether the magnesium-PAD relationship is independent of or modified by kidney function.

METHODS

A cohort of 11 839 participants free of PAD in the Atherosclerosis Risk in Communities Study at Visit 2 (1990-92) was studied. We investigated the association of serum magnesium and other bone-mineral metabolism markers [calcium, phosphorus, intact parathyroid hormone (iPTH) and intact fibroblast growth factor-23] with incident PAD using multivariable Cox proportional hazards regression.

RESULTS

Over a median of 23 years, there were 471 cases of incident PAD. The hazard ratio for incident PAD in Quartile 1 (<1.5 mEq/L) versus Quartile 4 (>1.7 mEq/L) of magnesium was 1.96 (95% confidence interval 1.40-2.74) after adjustment for potential confounders. Lower magnesium levels were associated with greater incidence of PAD, particularly in those with estimated glomerular filtration rate (eGFR) ≥60 mL/min/1.73 m2 (n = 11 606). In contrast, the association was largely flat in those with eGFR <60 mL/min/1.73 m2 (n = 233) with P-for-interaction 0.03. Among bone-mineral metabolism markers, only higher iPTH showed an interaction with kidney function (P-for-interaction 0.01) and iPTH >65 pg/mL was significantly related to PAD only in those with eGFR <60 mL/min/1.73 m2.

CONCLUSIONS

Lower magnesium was independently associated with incident PAD, but this association was significantly weaker in those with reduced kidney function. In contrast, higher iPTH levels were particularly related to PAD risk in this clinical population.

Blood Metabolic and Estradiol Level of Repeat Breeder and Fertile in Friesian Holstein Cross Breed Cows in the Tropic

BACKGROUND AND OBJECTIVE

The repeat breeding becomes the major reproduction problem in tropic area especially in Indonesia. It relates to blood metabolic and hormonal level. This research was conducted to investigate the level of blood metabolic and estradiol between the repeat breeder Friesian Holstein Cross Breed Cows (FHCB) and the fertile FHCB cows.

MATERIALS AND METHODS

Twenty FHCB cows in luteal phase on 2nd to 3rd lactation were used in this research. Group I consist of 10 repeat breeder FHCB cows and group II consist of 10 fertile FHCB cows. Blood samples were collected through jugular vein prior to feeding. The level of total protein, phosphorus, glucose, cholesterol and estradiol in serum were calculated. The data were analyzed by using the independent samples t-test for comparing the blood metabolic and estradiol between the repeat breeder FHCB cows and the fertile FHCB cows.

RESULTS

The results showed that repeat breeder FHCB cows were found to have lower level of all of the parameters of blood metabolic and estradiol descriptively, however, only the serum cholesterol and serum phosphorus had the significant difference (p<0.05) between the repeat breeder FHCB cows and the fertile FHCB cows.

CONCLUSION

It could be concluded that level of serum cholesterol and serum phosphorus played a role in repeat breeding.

Changes in 3-month mineral and bone disorder patterns were associated with all-cause mortality in prevalent hemodialysis patients with secondary hyperparathyroidism

BACKGROUND

There is limited evidence on the association between short-term changes in mineral and bone disorder parameters and survival in maintenance hemodialysis patients.

METHODS

We investigated the association between changing patterns of phosphorus, calcium and intact parathyroid hormone levels and all-cause mortality in hemodialysis patients with secondary hyperparathyroidism. Each parameter was divided into three categories (low [L], middle [M] and high [H]), and the changing patterns between two consecutive visits at 3-month intervals were categorized into nine groups (e.g., L-L and M-H). The middle category was defined as 4.0-7.0 mg/dL for phosphorous, 8.5-9.5 mg/dL for calcium and 200-500 pg/mL for intact parathyroid hormone. Adjusted incidence rates and rate ratios were analyzed by weighted Poisson regression models accounting for time-dependent exposures.

RESULTS

For phosphorus, shifts from low/high to middle category (L-M/H-M) were associated with a lower mortality compared with the L-L and H-H groups, whereas shifts from middle to low/high category (M-L/M-H) were associated with a higher mortality compared with the M-M group. For calcium, shifts from low/middle to high category (L-H/M-H) were associated with a higher mortality compared with the L-L and M-M groups, whereas shifts from high to middle category (H-M) were associated with a lower mortality compared with the H-H group. For intact parathyroid hormone, shifts from low to middle category (L-M) were associated with a lower mortality compared with the L-L group.

CONCLUSIONS

Changes in the 3-month patterns of phosphorus and calcium toward the middle category were associated with lower mortality. Our study also suggests the importance of avoiding hypercalcemia.

Vitamin D Receptor Polymorphisms in Sex-Frailty Paradox

The “male-female health-survival paradox” evidences that the survival advantage observed in women is linked to higher rates of disability and poor health status compared to men, a phenomenon also called the “sex-frailty paradox”. The depletion of vitamin D seems to play a role in the fragilization of old persons, and genetic polymorphisms of the vitamin D receptor (VDR) gene seem to be involved in regulating the vitamin D pathway. This study correlated the VDR gene polymorphisms (FokI, ApaI, BsmiI, and TaqI) with frailty, computed by frailty index (FI), in 202 persons (127 women and 75 men, aged from 60 to 116 years), aiming to capture the involvement of vitamin D in the sex-frailty paradox. The results showed slightly higher FI (p = 0.05), lower levels of 25(OH)D (p = 0.04), and higher levels of parathyroid hormone PTH (p = 0.002) and phosphorus (p < 0.001) in women than in men. Interestingly, the ApaI minor allele (Aa + aa) showed a significant positive association with FI (p = 0.03) and a negative association with inorganic phosphorus values (p = 0.04) compared to AA genotype only in women, regardless of age. The exact mechanism and the causal role that, in old women, links ApaI polymorphism with frailty are still unclear. However, we could speculate that a specific genetic profiling, other than 25(OH)D levels, play a role in the sex-frailty paradox.

Recent advances in understanding and managing secondary hyperparathyroidism in chronic kidney disease

Secondary hyperparathyroidism is a complex pathology that develops as chronic kidney disease progresses. The retention of phosphorus and the reductions in calcium and vitamin D levels stimulate the synthesis and secretion of parathyroid hormone as well as the proliferation rate of parathyroid cells. Parathyroid growth is initially diffuse but it becomes nodular as the disease progresses, making the gland less susceptible to be inhibited. Although the mechanisms underlying the pathophysiology of secondary hyperparathyroidism are well known, new evidence has shed light on unknown aspects of the deregulation of parathyroid function. Secondary hyperparathyroidism is an important feature of chronic kidney disease-mineral and bone disorder and plays an important role in the development of bone disease and vascular calcification. Thus, part of the management of chronic kidney disease relies on maintaining acceptable levels of mineral metabolism parameters in an attempt to slow down or prevent the development of secondary hyperparathyroidism. Here, we will also review the latest evidence regarding several aspects of the clinical and surgical management of secondary hyperparathyroidism.

Development of evocalcet for unmet needs among calcimimetic agents

INTRODUCTION

The calcium-sensing receptor is an important treatment target for secondary hyperparathyroidism (SHPT) in patients undergoing dialysis. In addition to vitamin D receptor activator, cinacalcet has recently been widely used for SHPT management, and the significant suppression of parathyroid hormone (PTH) with better control of serum calcium and phosphorus has been reported. However, low adherence and insufficient dose escalation mainly due to frequent gastrointestinal adverse events, still remain as major issues. To overcome these unmet needs, we have developed a new oral calcimimetic agent evocalcet, which has recently been approved by the Pharmaceutical Affairs Act in Japan.

AREAS COVERED

PubMed was searched from inception until April 2020 with the word evocalcet to summarize the development of this new calcimimetic agent, its pharmacokinetics, and the results of clinical trials, along with an overview of the differences among calcimimetic agents. This review also includes the management of SHPT with a focus on calcimimetics.

EXPERT OPINION

Evocalcet evoked fewer gastrointestinal-related adverse events while suppressing PTH at a lower dose than cinacalcet. These data suggest evocalcet may contribute to better adherence and sufficient dose escalation in patients with SHPT. Whether or not evocalcet improves clinical outcomes remains to be elucidated.

Mineral Intake and Clinical Symptoms in Adult Patients with Hypophosphatasia

BACKGROUND

Hypophosphatasia (HPP) is a rare inherited metabolic disorder characterized by deficient activity of the tissue-nonspecific alkaline phosphatase entailing impaired turnover of phosphorus metabolites. Dietary mineral intake is suspected to influence clinical symptoms of HPP, but scientific evidence is missing.

METHODS

Cross-sectional matched-pairs study collecting comprehensive data on nutrient intake in 20 HPP patients and 20 unaffected, age- and gender-matched controls. Dietary information and clinical symptoms were documented in detail over 7 consecutive days using structured diaries.

RESULTS

Baseline data and type of energy-supplying nutrients were balanced between both groups. Median nutritional intake of phosphorus and calcium were significantly lower in HPP patients versus controls, which is partially attributable to lower energy consumption in HPP patients. Differences regarding phosphorus and calcium (Ca/P) ratio and uptake of magnesium, zinc, and vitamin B6 were not statistically significant. Both high (≥ 1375 mg/d) and low intakes (< 1100 mg/d) of phosphorus were significantly associated with an increased frequency of neuropsychiatric symptoms (P = 0.02). Similarly, very high and very low intake of calcium was significantly associated with musculoskeletal (P < 0.01), gastrointestinal (P = 0.02), and neuropsychiatric (P < 0.001) symptoms. An increased Ca/P ratio was associated with increased tiredness/fatigue (P < 0.01), whereas a decreased Ca/P was associated with gastrointestinal issues (P = 0.01).

CONCLUSION

Phosphorus and calcium intake seem reduced in HPP patients along with reduced total energy consumption. Particularly high as well as very low absolute or unbalanced phosphorus and calcium intake are associated with an increased frequency of clinical symptoms.