Mabry Syndrome in a Child of South Asian Descent.

Mabry syndrome is the triad of seizures, hyperphosphatasia, and mental disability. It usually manifests in first year of life and has an autosomal recessive mode of inheritance. Besides the usual triad, other manifestations of Mabry syndrome include hypoplasia of distal phalanges, brachytelencepahly, gastrointestinal malformations and constipation, hypertelorism, short nose with a broad nasal bridge and dip, and thin upper lip with down turned corners of the mouth. More than 20 cases of Mabry syndrome have been reported in medical literature. Herein, we report the case of a six-month child with Mabry syndrome that presented with decreased neck holding, hypotonia and delayed motor milestones. The child also had a high-arched palate and hyperplastic malar eminences. Constipation was present but had a delayed onset, starting at 19 months of age. This is the first case of Mabry syndrome occurring in a child of South Asian descent.

Cómo estimar la eficacia de un captor del fósforo / How to assess the efficacy of phosphate binders

Antecedentes y objetivos: Es difícil estimar clínicamente la eficacia de los captores de fósforo (CP). Este estudio analiza los cambios que se producen en la fosfatemia y excreción urinaria de fósforo tras la administración de CP a pacientes con enfermedad renal crónica, y la utilidad de la relación entre la excreción urinaria de fósforo y la tasa de catabolismo proteico (Po/TCP) en la estimación de la eficacia de estos fármacos. Métodos: Estudio retrospectivo de observación en una cohorte de pacientes adultos con enfermedad renal crónica en estadios 4-5. Se compararon parámetros bioquímicos basales y 45-60 días después de un tratamiento con dieta baja en fósforo más CP (subgrupo «captor»=260 pacientes) o solo con los consejos dietéticos (subgrupo «control»=79 pacientes). Resultados: La carga de fósforo (excreción urinaria total) por unidad de función renal (Po/GFR) fue el parámetro mejor relacionado con la fosfatemia (R2=0,61). La cifra media de Po/TCP fue de 8,2±2,3mg de fósforo por gramo de proteína. Tras la administración de CP, la fosfatemia descendió un 11%, la fosfaturia un 22%, la tasa de catabolismo proteico un 7% y la Po/TCP un 15%. En el subgrupo control la Po/TCP se incrementó un 20%. La excreción urinaria de fósforo y de nitrógeno ureico se correlacionaron fuertemente de forma lineal antes y después del tratamiento con CP o tras los consejos dietéticos en el subgrupo control. Conclusiones: La Po/TCP es un parámetro que podría reflejar la absorción intestinal de fósforo y, por tanto, sus variaciones tras la administración de CP podrían servir para estimar la eficacia de estos fármacos (AU)

Background and aims: The efficacy of phosphate binders is difficult to be estimated clinically. This study analyzes the changes in serum phosphate and urinary phosphate excretion after the prescription of phosphate binders (PB) in patients with chronic kidney disease stage 4-5 pre-dialysis, and the usefulness of the ratio between total urinary phosphate and protein catabolic rate (Pu/PCR) for estimating the efficacy of PB. Methods: This retrospective observational cohort study included adult chronic kidney disease patients. Biochemical parameters were determined baseline and after 45-60 days on a low phosphate diet plus PB (‘binder’ subgroup=260 patients) or only with dietary advice (‘control’ subgroup=79 patients). Results: Phosphate load (total urinary excretion) per unit of renal function (Pu/GFR) was the best parameter correlated with serum phosphate levels (R2=0.61). Mean±SD level of Pu/PCR was 8.2±2.3mg of urinary phosphate per each g of estimated protein intake. After treatment with PB, serum phosphate levels decreased by 11%, urinary phosphate 22%, protein catabolic rate 7%, and Pu/PCR 15%. In the control subgroup, Pu/PCR increased by 20%. Urinary phosphate and urea nitrogen excretion correlated strongly, both baseline and after PB or dietary advice. Conclusions: The proposed parameter Pu/PCR may reflect the rate of intestinal phosphate absorption, and therefore, its variations after PB prescription may be a useful tool for estimating the pharmacological efficacy of these drugs (AU)

[Experience with active vitamin D metabolites in phosphorus-calcium metabolic disorders in patients with predialysis chronic kidney disease].

AIM: To evaluate the efficacy and safety of alfacalcidol and paracalcitol used to correct impaired phosphorus-calcium metabolism (PCM) in patients with predialysis chronic kidney disease (CKD). SUBJECTS AND METHODS: Examinations were made in 128 patients with Stages III-V CKD, including 89 (69.5%) patients with chronic glomerulonephritis, 30 (23.4%) with chronic tubulointerstitial nephritis, and 9 (7.1%) with hypertensive nephrosclerosis. Impaired PCM was detected in 90 (70.3%) of the examined patients. According to the pattern of the previous therapy, all the 90 CKD patients with PCM disorders were divided into 3 groups: 1) 32 patients with Stages IIIB-V CKD who had taken oral alfacalcidol 0.25 microg/day; 2) 28 patients with Stages IIIB-V CKD who had used oral paricalcitol 1 microg/day; 3) 30 patients with Stages IIIB-V CKD who had not received, as self- motivated, active vitamin D metabolites at the predialysis stage. RESULTS: Alfacalcidol and paricalcitol were quite satisfactorily tolerated by the patients. After 3 months of initiation of the use of these agents, Groups 1 and 2 patients with predialysis CKD and baseline elevated blood intact parathyroid hormone (iPTH) levels could not only achieve, but also maintain target blood iPTH levels. In the patients taking paricalcitol, the urinary protein level decreased more promptly; moreover, by the end of month 6 the reduction in blood pressure (BP) was more significant than in those using alfacalcidol (p < 0.05). Comparison of the effects of angiotensin-converting enzyme inhibitors in combination with alfacalcidol or paricalcitol on BP changes and left ventricular mass index indicated that the most pronounced positive changes occurred when angiotensin-converting enzyme inhibitors were used in combination with paricalcitol. CONCLUSION: The use of paricalcitol in predialysis CKD with PTH hyperproduction results in not only normalization of the levels of both PTH and osseous isoenzyme of alkaline phosphatase, but also in significantly reduced daily proteinuria and regression of left ventricular hypertrophy and chronic heart failure.

Efecto en el control del fósforo sérico tras la sustitución de hidróxido de aluminio por acetato cálcico/carbonato magnésico en pacientes en hemodiálisis / The effect of replacing aluminium hydroxide with calcium acetate/magnesium carbonate on serum phosphorus control in haemodialysis patients

Introducción: El acetato cálcico/carbonato magnésico (MgCO3) es un quelante de fósforo con ventajas en cuanto a coste, seguridad y tolerancia, con similar eficacia a la de otros fármacos. El objetivo del estudio es evaluar los efectos sobre el metabolismo fosfocálcico al sustituir hidróxido de aluminio [Al(OH3)] por MgCO3 en una cohorte de pacientes en hemodiálisis. Material y métodos: Se incluyen 21 pacientes con fósforo < 5 mg/dl, con Al(OH3) como único quelante. La conversión a MgCO3 se realizó sin variar el número de comprimidos. Se registraron características clínico-demográficas, tratamiento para hiperparatiroidismo secundario y parámetros analíticos antes de la conversión, y mensualmente durante cuatro meses. Resultados: La fosforemia disminuyó de 4,52 ± 0,99 a 4,02 ± 1,07 mg/dl (p = 0,027), con una reducción del producto calcio-fósforo de 40,20 ± 10,44 a 35,16 ± 11,06 mg2/dl2 (p = 0,037). No encontramos variaciones significativas en los niveles de calcio, hormona paratiroidea o 25-OH-vitamina D3. El número prescrito de comprimidos diarios se redujo de 3,33 ± 2,29 a 2,15 ± 2,21 (p = 0,020). Los tratamientos concomitantes no variaron. Observamos un aumento significativo inicial de la magnesemia de 2,21 ± 0,24 a 2,43 ± 0,39 mg/dl (p = 0,001), que posteriormente se mantuvo estable. Encontramos una disminución del aluminio sérico de 14,91 ± 8,55 a 8,47 ± 3,98 µg/l (p = 0,004), con niveles en rango recomendado en todos los pacientes. Conclusiones: El MgCO3 permite un buen control del fósforo sérico en pacientes en hemodiálisis previamente bien controlados con Al(OH)3, con menos comprimidos diarios. Se produce un ligero aumento en el magnesio sérico, sin significado clínico a corto plazo. Desconocemos los efectos de este aumento a más largo plazo (AU)

Introduction: Calcium acetate/magnesium carbonate (MgCO3) is a phosphorus binder with advantages in terms of cost, safety and tolerance and it has a similar efficacy to other drugs. The objective of the study is to assess the effects of replacing aluminium hydroxide [Al(OH3)] with MgCO3 on phosphorus and calcium metabolism in a cohort of haemodialysis patients. Materials and methods: We included 21 patients with phosphorus <5mg/dl, with Al(OH3) as the only binder. The conversion to MgCO3 was carried out without changing the number of pills. We recorded clinical-demographic characteristics, treatment for secondary hyperparathyroidism and laboratory parameters before conversion and every month for four months. Results: Phosphataemia decreased from 4.52±0.99 to 4.02±1.07mg/dl (p=.027), and there was a decrease in the calcium-phosphorus product from 40.20±10.44 to 35.16±11.06mg2/dl2 (p=.037). We did not observe significant changes in levels of calcium, parathyroid hormone or 25-OH-vitamin D3. The daily number of pills prescribed was reduced from 3.33±2.29 to 2.15±2.21 (p=.020). Concomitant treatments were not altered. We observed an initial significant increase in magnesaemia from 2.21±0.24 to 2.43±0.39mg/dl (p=.001), which subsequently remained stable. We found a decrease in serum aluminium from 14.91±8.55 to 8.47±3.98µg/l (p=.004), with levels within the recommended range in all patients. Conclusions: MgCO3 allowed good control of serum phosphorus in haemodialysis patients who were previously well controlled with Al(OH)3, using fewer daily pills. There was a slight increase in serum magnesium, without short-term clinical significance. We do not know the effects of this increase in the longer term (AU)

Phosphorus metabolic disorder of Guizhou semi-fine wool sheep.

Guizhou semi-fine wool sheep are affected by a disease, characterized by emaciation, lameness, stiffness in the gait, enlargement of the costochondral junctions, and abnormal curvature in the long bones. The objective of this study was to determine possible relationships between the disease and mineral deficiencies. Samples of tissue and blood were collected from affected and unaffected sheep. Samples of soil and forage were collected from affected and unaffected areas. The samples were used for biochemical analyses and mineral nutrient measurements. Results showed that phosphorus (P) concentrations in forage samples from affected areas were significantly lower than those from unaffected areas (P < 0.01) and the mean ratio of calcium (Ca) to P in the affected forage was 12:1. Meanwhile, P concentrations of blood, bone, tooth, and wool from the affected sheep were also significantly lower than those from the unaffected group (P < 0.01). Serum P levels of the affected animals were much lower than those of the unaffected ones, whereas serum alkaline phosphatase levels from the affected were significantly higher than those from the unaffected (P < 0.01). Inorganic P levels of the affected sheep were about half of those in the control group. Oral administration of disodium hydrogen phosphate prevented and cured the disease. The study clearly demonstrated that the disease of Guizhou semi-fine wool sheep was mainly caused by the P deficiency in forage, as a result of fenced pasture and animal habitat fragmentation.

Captores del fósforo: preferencias de los pacientes en hemodiálisis y su repercusión sobre el cumplimiento del tratamiento y el control del fósforo / Phosphorus binders: preferences of patients on haemodialysis and its impact on treatment compliance and phosphorus control

Introducción: En la actualidad disponemos de un amplio abanico de captores del fósforo (CF), pero sabemos poco acerca de las preferencias de los pacientes y de su repercusión sobre el cumplimiento del tratamiento y el control de los niveles de fósforo. Objetivo: Estudiar las preferencias y creencias de los pacientes respecto a los CF, y su influencia sobre el cumplimiento del tratamiento y el control de los niveles de fósforo. Pacientes y métodos: Estudio observacional transversal. Se incluyeron 121 pacientes que respondieron un cuestionario genérico de cumplimiento del tratamiento (SMAQ) y a un cuestionario específico sobre cumplimiento del tratamiento con CF, tipo de CF preferido y razones de dicha preferencia. Todos los pacientes entrevistados habían probado dos o tres CF. Las consecuencias de la falta de cumplimiento del tratamiento con CF se estimaron indirectamente analizando los valores promedio de fósforo sérico. Resultados: El 40% de los pacientes era incumplidor según el cuestionario SMAQ; se encontró una asociación estadísticamente significativa entre la falta de cumplimiento en general y no alcanzar el objetivo de fósforo sérico promedio <5,5 mg/dl (OR = 4,8; IC 95%, 1,0-6,6; p = 0,02). El 21,4% de los pacientes reconocía un incumplimiento específico para los CF; estos pacientes presentaban una mayor probabilidad de tener cifras medias de fósforo >5,5 mg/dl (OR = 4,7; IC 95%, 1,1-6,5; p = 0,03). Un 43,8% de los pacientes no refirió tener preferencias entre los diferentes tipos de CF; para el resto de pacientes, el CF preferido fue Royen(R), seguido de Fosrenol(R), Renagel(R) y Pepsamar(R). Las razones expresadas para el desagrado con el Renagel® fueron las siguientes: incomodidad en la toma por su gran tamaño (28,8%), necesidad de tomar muchos comprimidos y gran consumo de agua (57,7%) e intolerancia gástrica (13,3%). En el caso del Fosrenol(R) incómodo de tomar (72,7%) e intolerancia gástrica (27,2%); para el Pepsamar(R): mal sabor (54,5%) e intolerancia gástrica (45,4%). Sólo al 9,4% no le gustaba el Royen(R). Al analizar los conocimientos de los pacientes respecto a la utilidad de los CF, un 42% sabía que servían para controlar el fósforo; un 52% no lo sabía y un 6% tenía ideas equivocadas. En cuanto a su importancia: un 47% no conocía por qué son importantes; un 2% tenía ideas erróneas; un 9% creía que era beneficioso para la salud; un 11% creía que era bueno «porque lo dice el medico»; un 26% porque controla el fósforo y un 5% lo relacionaba con el hueso. Ningún paciente relacionó los CF con la enfermedad cardiovascular. Un 24,4% no se llevaba los CF cuando salía fuera de casa o estaba con los amigos; eran pacientes más jóvenes a quienes se les habían prescrito un mayor número de comprimidos de CF y que presentaban un mayor riesgo de no cumplir el objetivo de fósforo (OR = 10,5; IC 95%, -1,8 a -16,4; p <0,001). El porcentaje de pacientes a quienes no les gustaba el CF prescrito fue del 54,5%; dichos pacientes presentaban un mayor riesgo de tener niveles séricos de fósforo >5,5 mg/dl (OR = 13.3; IC 95%, 1,1-1,5; p = 0,0001). Paradójicamente, los pacientes que no cumplían con el tratamiento demostraban un mejor conocimiento de su uso (OR = 17,3; IC 95%, 2,2-10,1; p <0.0001) e importancia (OR = 10,4; IC 95%, 1,5-6,6; p = 0,001). Conclusión: Los pacientes a los que se les habían prescrito CF que no les gustaban tenían un peor control de los niveles de fósforo sérico y se les habían recomendado dosis más altas de los fármacos. El conocimiento de las preferencias de los pacientes acerca de las medicaciones que se les prescriben puede ser un factor esencial para conseguir un mayor cumplimiento del tratamiento y, por ende, lograr mejores resultados en la consecución de los objetivos terapéuticos (AU)

Introduction: Non-adherence to phosphate binding (PB) medication may play a role in the difficulty in achieving the targets for phosphorus. We have a wide spectrum of PB but preferences of patients are poorly understood. Objective: to study the patients’ preferences and beliefs regarding PB and their influence on adherence and serum phosphate. Methods: A cross-sectional cohort study was performed. A total of 121 hemodialysis patients answered a specific questionnaire in which they were questioned about adherence, the type of PB they preferred and the reasons for their choice. All patients questioned tasted two or three PB. The consequence of non-adherence to PB was estimated indirectly by determination of serum phosphorus. Results: Specific noncompliance with PB medication was recognized by 21.4% of patients. Patients non-adherent specifically to PB were more likely to have P levels >5.5 mg/dl (χ2: 4.7; 95% CI 1.07-6.5; p = 0.03). Paradoxically, non-adherent patients showed greater knowledge of the use (χ2: 17.3; 95% CI -2.2-10.1; p <0.0001) and importance of the drug (χ2: 10.4; 95% CI -1.5-6.6; p = 0.001). The percentage of patients prescribed binders that they did not like was 54.5%. Patients who were taking PB that they did not like had a greater risk of having P levels >5.5 mg/dl) (χ2: 13.3; 95% CI -1.1-1.5; p = 0.0001). Calcium acetate was the prefered PB in 47.1% of patients, lanthanum carbonate in 40%, sevelamer in 20.6% and aluminum hydroxide in 19.4%. The reasons claimed by patients for their negative ratings of PB were the type of dosage form, the taste, the number of tablets and gastric intolerance. Gastric intolerance and bad taste were more frequent in aluminum hydroxide patients (19.4% and 22.2%, respectively). Sevelamer received complaints about its dosage form because the tablets were too large and a large number of tablets were required (27.2%). 17.7% of patient who were taking lanthanum carbonate did not like the chewable tablets. Conclusion: patients who were taking binders that they did not like had worse serum P levels and were prescribed higher doses of binders. Knowing patients' preferences about the drugs prescribed may be a key factor in achieving adequate adherence to treatment (AU)

[Phosphatonins: novel insights and clinical perspectives]. / Le fosfatine: recenti acquisizioni e possibili evoluzioni nella clinica.

Phosphate plays a vital role in several biological processes including energy and nucleic acid metabolism, cell signaling and bone mineralization. Several endocrine factors coordinately act on the intestine, kidney and bone to maintain their physiological homeostasis. A number of peptides, collectively known as phosphatonins, have recently been identified as regulators of phosphate metabolism in physiological and pathological conditions. These factors--fibroblast growth factors (FGF) 23 and 7, secreted frizzled related protein 4 (sFRP-4), and matrix extracellular phosphoglycoprotein (MEPE)--primarily regulate tubular phosphate reabsorption by acting on the transmembrane expression of SLC34 sodium-phosphate cotransporters. FGF- 23, FGF-7 and sFRP-4 also inhibit the biosynthesis of 1,25(OH)2D3, leading to decreased intestinal phosphate absorption. In this review, we discuss the biological properties of these peptides, their physiological roles, and the alterations in their concentrations in various hypophosphatemic and hyperphosphatemic clinical disorders.

Phosphate binders in chronic kidney disease and end-stage renal disease: a patient-centered approach.

Disorders of calcium and phosphorus metabolism are associated with significant morbidity and mortality in patients with advanced chronic kidney disease. These patients typically require oral phosphate binders to maintain phosphorus homeostasis, but the choice of which among several agents to use has been actively investigated and debated. Recent debate has been polarized between those who favor calcium-based binders for their proven efficacy and relatively low cost and those who favor sevelamer for its putative beneficial effects on inflammatory biomarkers and vascular calcification. This review summarizes the current state of the art of prescribing phosphate binders, ranging from large-scale clinical trials to focused mechanistic studies, and proposes that the available evidence does not conclusively prove the relative superiority of any one binder.

Avances experimentales en metabolismo mineral / No disponible

Uno de los problemas más importantes a los que se enfrentan los nefrólogos es el alto grado de mortalidad cardiovascular de los pacientes en diálisis. Este aumento de la enfermedad cardiovascular se ha asociado a varios factores, pero entre ellos, la hiperfosfatemia brilla con luz propia. Los ni-veles plasmáticos de fósforo considerados normales en estos pacientes se han ido bajando paulatinamente en los últimos años. Por tanto, el control del fósforo en el paciente con enfermedad renal crónica se ha convertido en un retoque ha incentivado la investigación básica en los últimos años. La siguiente revisión pretende reunir los resultados más novedosos presentados en el último año, haciendo énfasis en los métodos de control de la absorción de fósforo, de su eliminación renal y en las calcificaciones vasculares, que son una de las consecuencias directas más graves de la hiperfosfatemia (AU)

One of the most important problems faced by nephrologists is the high degree of cardiovascular mortality in patients on dialysis. This increase in cardiovascular disease has been associated with various factors, but, among them, hyperphosphatemia stands out particularly. The serum phosphate levels considered normal in these patients have gradually decreased in recent years. Therefore, phosphate control in the chronic kidney disease patient has become a challenge that has stimulated basic research in recent years. The aim of the following review is to bring together the most novel results presented in the last year, with emphasis on the methods for control of phosphate absorption, its elimination by the kidneys and vascular calcifications, which are one of the most serious direct consequences of hyperphosphatemia (AU)

[Therapeutic options for mineral metabolism disorders in dialysis patients: a case report]. / Opzioni terapeutiche per la gestione clinica delle alterazioni del metabolismo minerale in dialisi: un caso clinico.

Mineral metabolism disorders are well-recognized complications in patients with chronic kidney disease (CKD). Furthermore, hyperphosphatemia and secondary hyperparathyroidism are associated with both renal osteodystrophy and cardiovascular disease. During the last 5 years, new therapeutic options have become available to treat these conditions in CKD. We describe the case of a 70-year-old lady with a dialysis history of 5 years and a number of cardiovascular risk factors (hypertension, hypercholesterolemia and obesity). Unfortunately, the patient was poorly compliant with any pharmaceutical treatment. After 2 years, a pharmacological approach with a low dosage of calcium salts and sevelamer HCl, subsequently changed to lanthanum carbonate, intravenous paricalcitol, and cinacalcet HCl reached the goals suggested by the current guidelines. Every nephrologist should look at the pathogenesis and treatment of hyperphosphatemia and secondary hyperparathyroidism. New options are now available and may help the clinician to obtain satisfactory short- and long-term outcomes in the treatment of this disease.

Magnesium carbonate is an effective phosphate binder for chronic hemodialysis patients: a pilot study.

OBJECTIVE: This study was designed to evaluate the efficacy of magnesium carbonate as a phosphate binder in hemodialysis patients. DESIGN: This study was a prospective, randomized, open-label trial comparing magnesium carbonate/calcium carbonate versus calcium acetate as a sole phosphate binder. SETTING: This study involved outpatient hemodialysis. PARTICIPANTS: We recruited 30 stable hemodialysis patients without a history of frequent diarrhea. INTERVENTION: After receiving informed consent, we randomized patients 2:1 to magnesium carbonate versus calcium acetate. The dose of each binder was titrated to achieve the Kidney Disease Outcomes Quality Initiative (K/DOQI) phosphate target of <5.5 mg/dL. MAIN OUTCOME MEASURE: The efficacy-phase serum phosphorus concentration and the percentage of patients meeting K-DOQI targets for phosphorus, along with the daily elemental calcium intake, were the primary outcome measures. RESULTS: Magnesium carbonate provided equal control of serum phosphorus (70.6% of the magnebind group and 62.5% of the calcium acetate group had their average serum phosphorus within the K-DOQI target during the efficacy phase), while significantly reducing daily elemental calcium ingestion from phosphate binders (908 +/- 24 vs. 1743 +/- 37 mg/day, P < .0001). CONCLUSION: Magnesium carbonate was generally well-tolerated in this selected patient population, and was effective in controlling serum phosphorus while reducing elemental calcium ingestion.

Optimising the treatment of hyperphosphatemia and vascular calcification in chronic kidney disease.

Accelerated atherosclerosis and vascular calcifications (VC) play a central role in the pathogenesis of cardiovascular disease in chronic kidney disease (CKD) patients. Mineral metabolism disorders and increased serum calcium-phosphate product have been recently investigated as inducing factors of cardiovascular calcification. In fact, cardiovascular disease in renal failure appears greatly associated with bone metabolism alterations. Recently, the treatment of hyperphosphatemia in CKD patients changed from either calcium- or aluminium-based phosphate-binders to new free-calcium and aluminium phosphate binders, such as sevelamer hydrochloride and lanthanum carbonate. Therefore, control of serum phosphate in CKD patients becomes crucial in preventing increases in calcium-phosphate product, secondary hyperparathyroidism and ultimately VC.

Emerging drugs for hyperphosphatemia.

Cardiovascular mortality is the leading cause of death in the uremic patient. Hyperphosphatemia is considered an independent risk factor associated with cardiovascular morbidity and mortality in dialysis patients. As phosphate control is not efficient with diet or dialysis, phosphate binders are commonly prescribed in patients with chronic renal failure. Aluminum salts, the first phosphate binders, even if effective, have several side effects due to their deposition in CNS, bone and hematopoietic cells. Calcium-containing phosphate binders, used in the last 15 years, increase total body calcium load and may exacerbate metastatic calcification, thus, increasing the risk of cardiovascular mortality. Recently two new compounds non-aluminum and non-calcium phosphate binders, sevelamer hydrochloride and lanthanum carbonate, have been introduced. Sevelamer, besides the effect on phosphate, has been associated with reduction of coronary and aortic calcification and with other pleiotropic effects especially on lipid metabolism. Lanthanum carbonate has similar phosphate control to calcium-based binders with less incidence of hypercalcemia but long-term clinical studies are needed for testing long-term exposure. Recently the authors found in dialysis patients, that salivary phosphorus correlated with serum phosphorus. Therefore, they supposed that the use of salivary phosphate binders could reduce its absorption and represent a chance for reducing the serum phosphate concentration in uremic patients.

[New management of phosphocalcic abnormalities in dialysis patient]. / Nouveautés dans la prise en charge des anomalies du bilan phosphocalcique chez le patient dialysé.

Disorders of the phosphocalcic metabolism are frequent in dialysis patients. Such disorders are difficult to treat and have negative impact on bone health, but also on cardiovascular mortality. Hyperphosphoremia is a strong predictor of cardiovascular mortality. New phosphate binders are now available in Belgium. A new molecule acting on the calcium receptor of the parathyroid glands is able to control secondary and tertiary hyperparathyroidism in dialysis patients. These new therapies, specific for dialysis patients, will be reviewed in this article.

Lanthanum carbonate--a first line phosphate binder?

Hyperphosphatemia is associated with increased morbidity and mortality in dialysis patients. Oral phosphate binders are necessary to control serum phosphate in patients eating a normal diet and undergoing peritoneal dialysis or thrice weekly hemodialysis. Until recently, none of the available drugs came close to the model of an ideal oral binder, which would demonstrate high affinity, rapid binding regardless of pH, low solubility and absorption, lack of toxicity, palatability, and reasonable cost. Lanthanum carbonate is a safe and effective binder with data demonstrating no toxic effects after continuous exposure up to 6 years. Suggestions that absorption and accumulation of lanthanum is significant and of clinical importance do not stand up to close scrutiny and recommended it as a first line treatment for dialysis patients, particularly if they have evidence of vascular calcification.

Lanthanum carbonate as a first-line phosphate binder: the "cons".

Controlling serum phosphorus levels in patients with renal failure is critical. The use of oral phosphate-binding agents is universal for patients with end-stage kidney disease to reduce phosphate absorption. The therapeutic goal is to reduce serum phosphorus levels without disturbing calcium homeostasis or promoting accumulation of potentially toxic elements from the medication. Aluminum hydroxide effectively reduces serum phosphorus, but has largely been abandoned as a first-line phosphate binder because of hazards associated with metal absorption and tissue accumulation. Traditional calcium-based phosphate binders tend to promote hypercalcemia and calcium overloading, and are linked to accelerated cardiovascular calcification. Interest in aluminum-free, calcium-free phosphate-binding agents continues to grow. Sevelamer hydrochloride, a metal-free, calcium-free hydrogel, is not absorbed, has been proven safe and efficacious in controlling serum phosphorus, and is associated with attenuated progression of cardiovascular calcification. Lanthanum carbonate is a newer aluminum-free, calcium-free phosphate-binding agent. Lanthanum is a rare-earth trace metal with industrial and agricultural applications. As a therapeutic, this metal-based binder appears effective in reducing serum phosphorus, yet concerns remain about lanthanum accumulation in tissues during long-term oral administration. Similar to the metal aluminum, lanthanum is absorbed in the intestine and accumulates in body tissues, especially in the liver, bone, muscle, kidney, and brain. Moreover, the rate of intestinal absorption of lanthanum is enhanced in chronic renal failure. Our experience with aluminum hydroxide suggests caution regarding the long-term use of another metal-based agent that displays enhanced absorption in the uremic state and progressive tissue accumulation.

The role of magnesium binders in chronic kidney disease.

Magnesium is predominantly an intracellular cation that plays a critical role in cellular physiology. Serum levels are often slightly elevated in patients on chronic hemodialysis and older reports suggests that total body stores may also be increased, based on bone biopsies in patients treated with higher dialysate magnesium levels than are currently in use today. Several studies have shown that magnesium, particularly in the form of magnesium carbonate, is an effective phosphate binder and can decrease patients' exposure to calcium. Retrospective studies suggest that magnesium may prevent vascular calcification in dialysis patients, although this remains controversial and has not been evaluated prospectively. Magnesium may reduce arrhythmias postoperatively and, while it may theoretically reduce arrhythmic death in dialysis patients, this hypothesis has never been tested. While short-term or adjuvant use of magnesium carbonate appears safe and effective as a phosphate binder, more studies are needed to evaluate the long-term effects on vascular calcification, bone histology, and mortality.

New developments in the management of hyperphosphatemia in chronic kidney disease.

Hyperphosphatemia is a characteristic complication of significant chronic kidney disease. Elevated serum phosphorous is associated with reduced survival. Hyperphosphatemia has long been recognized as predisposing to uremic bone disease and disorders of parathyroid function. Furthermore, elevated serum phosphate has been implicated particularly in the development of cardiovascular structural and functional abnormalities. Given the limitations of restricting phosphate in the diet and the inadequate removal by conventional dialysis regimes, nephrologists rely on the use of additional medications to control serum levels (currently oral phosphate binders). This review focuses on new agents and therapeutic approaches dealing with hyperphosphatemia in chronic kidney disease, that are not currently licensed and available in routine clinical practise. This article attempts to review therapies under development and considers additional effects that the next generation of agents may bring over and above those already within the therapeutic armamentarium.