Weibel-Palade bodies: function and role in thrombotic thrombocytopenic purpura and in diarrhea phase of STEC-hemolytic uremic syndrome.

Vascular endothelial cells are equipped with numerous specialized granules called Weibel-Palade bodies (WPBs). They contain a cocktail of proteins that can be rapidly secreted (3-5 min) into the vascular lumen after an appropriate stimulus such as thrombin. These proteins are ready without synthesis.

Hyporeninemic hypoaldosteronism in RMND1-related mitochondrial disease.

Background: RMND1 is a nuclear gene needed for proper function of mitochondria. A pathogenic gene will cause multiple oxidative phosphorylation defects. A renal phenotype consisting of hyponatremia, hyperkalemia, and acidosis is frequently reported, previously considered to be due to aldosterone insensitivity.

The cause of eyelid ptosis, orthostatic hypotension and exercise intolerance.

To provide more insight in the delay in diagnosis and expectation of treatment adapted for the paediatrician, the data were collected from patients described with dopamine beta-hydroxylase deficiency are evaluated. More insight in clinical features of dopamine beta-hydroxylase deficiency consisting mainly of eyelid ptosis, orthostatic hypotension, hypoglycaemia and exercise intolerance, explains the delay in diagnosis of this congenital disorder, although all symptoms some more concealed are present. An increasing experience by L-DOPS, a resurrection for the patient, allows recommendations for early treatment.

Human and animal fertility studies in cystinosis reveal signs of obstructive azoospermia, an altered blood-testis barrier and a subtherapeutic effect of cysteamine in testis.

Cystinosis is an inherited metabolic disorder caused by autosomal recessive mutations in the CTNS gene leading to lysosomal cystine accumulation. The disease primarily affects the kidneys followed by extra-renal organ involvement later in life. Azoospermia is one of the unclarified complications which are not improved by cysteamine, which is the only available disease-modifying treatment.

Blood, urine and cerebrospinal fluid analysis in TH and AADC deficiency and the effect of treatment.

Background: Aromatic L-amino acid decarboxylase (AADC) deficiency and tyrosine hydroxylase (TH) deficiency are rare inherited disorders of monoamine neurotransmitter synthesis which are typically diagnosed using cerebrospinal fluid examination of monoamine neurotransmitter metabolites. Until now, it has not been systematically studied whether analysis of monamine neurotransmitter metabolites in blood or urine has diagnostic value as compared to cerebrospinal fluid examination, or whether monoamine neurotransmitter metabolites in these peripheral body fluids is useful to monitor treatment efficacy.

Methods: Assessment, both by literature review and retrospective analysis of our local university hospital database, of monoamine neurotransmitter metabolites in urine, blood and cerebrospinal fluid, and serum prolactin levels, before and during treatment in patients with AADC and TH deficiency.

Clinical presentation and long-term follow-up of dopamine beta hydroxylase deficiency.

Dopamine beta hydroxylase (DBH) deficiency is an extremely rare autosomal recessive disorder with severe orthostatic hypotension, that can be treated with L-threo-3,4-dihydroxyphenylserine (L-DOPS). We aimed to summarize clinical, biochemical, and genetic data of all world-wide reported patients with DBH-deficiency, and to present detailed new data on long-term follow-up of a relatively large Dutch cohort. We retrospectively describe 10 patients from a Dutch cohort and 15 additional patients from the literature.

Serum Shiga toxin 2 values in patients during acute phase of diarrhoea-associated haemolytic uraemic syndrome.

Aim: Shiga toxins are delivered via systemic circulation and are considered to be the cause of diarrhoea-associated haemolytic uraemic syndrome (HUS), as they injure endothelial cells, particularly in the glomeruli. This study measured Shiga toxin 2 (Stx2) in the serum of children affected in by HUS due to Stx2 producing Escherichia coli.

Methods: The concentration of free Stx2 was measured in the serum of 16 children, collected immediately after admission to the clinic in the acute phase of HUS, using a sandwich enzyme-linked immunosorbent assay.

Urinary excretion of polyols and sugars in children with chronic kidney disease.

Background: The urinary concentrations of monosaccharides and polyols are used for diagnosing inborn errors of metabolism and renal tubular disorders. Reference values are age-related and depend on the method of detection. However, the influence of the renal function is often still neglected.

Segmental transport of Ca²⁺ and Mg²⁺ along the gastrointestinal tract.

Calcium (Ca(2+)) and magnesium (Mg(2+)) ions are involved in many vital physiological functions. Since dietary intake is the only source of minerals for the body, intestinal absorption is essential for normal homeostatic levels. The aim of this study was to characterize the absorption of Ca(2+) as well as Mg(2+) along the gastrointestinal tract at a molecular and functional level.

The effect of shiga toxin on weibel-palade bodies in primary human endothelial cells.

Background/aims: Diarrhea-associated hemolytic uremic syndrome is associated with the presence of Shiga toxin (Stx1, Stx2 and several variants) in the circulation. The aim of this study is to examine the possible triggering effect of Stx1 on the exocytosis of Weibel-Palade bodies (WPbs).

Methods: Cultured human umbilical venous endothelial cells (HUVECs) and glomerular microvascular endothelial cells (GMVECs) were stimulated by thrombin and Stx1 in both static and flowing conditions.

Switch in FGFR3 and -4 expression profile during human renal development may account for transient hypercalcemia in patients with Sotos syndrome due to 5q35 microdeletions.

Context: Sotos syndrome is a rare genetic disorder with a distinct phenotypic spectrum including overgrowth and learning difficulties. Here we describe a new case of Sotos syndrome with a 5q35 microdeletion, affecting the fibroblast growth factor receptor 4 (FGFR4) gene, presenting with infantile hypercalcemia.

Objective: We strove to elucidate the evanescent nature of the observed hypercalcemia by studying the ontogenesis of FGFR3 and FGFR4, which are both associated with fibroblast growth factor (FGF) 23-mediated mineral homeostasis, in the developing human kidney.

Pre-treatment of dairy and breast milk with sevelamer hydrochloride and sevelamer carbonate to reduce phosphate.

Introduction: Young children and infants with chronic kidney disease are at increased risk of hyperphosphatemia because of high intake of dairy products. Hyperphosphatemia leads to metastatic calcifications and an increased risk of cardiovascular complications. Sevelamer is an effective phosphate binder, but for children it has important practical disadvantages: it clogs enteral feeding tubes and can cause gastrointestinal complaints.

The paradox of hyperdopaminuria in aromatic L-amino Acid deficiency explained.

Aromatic L-amino acid decarboxylase (AADC) decarboxylates 3,4-L-dihydroxylphenylalanine (L-dopa) to dopamine, and 5-hydroxytryptophan to serotonin. In AADC deficiency, dopamine and serotonin deficiency leads to a severe clinical picture with mental retardation, oculogyric crises, hypotonia, dystonia, and autonomic dysregulation. However, despite dopamine deficiency in the central nervous system, urinary dopamine excretion in AADC-deficient patients is normal to high.

Evaluation of hypomagnesemia: lessons from disorders of tubular transport.

Hypomagnesemia is a highly prevalent clinical condition affecting a large number of hospitalized patients. A decrease in systemic magnesium concentration may lead to impaired function of both neurologic and cardiovascular systems. The kidney has a pivotal role in magnesium handling by adjusting the urinary excretion of this ion in order to maintain systemic concentrations within a narrow range.

Drug-induced alterations in Mg2+ homoeostasis.

Magnesium (Mg2+) balance is tightly regulated by the concerted actions of the intestine, bone and kidneys. This balance can be disturbed by a broad variety of drugs. Diuretics, modulators of the EGFR (epidermal growth factor receptor), proton pump inhibitors, antimicrobials, calcineurin inhibitors and cytostatics may all cause hypomagnesaemia, potentially leading to tetany, seizures and cardiac arrhythmias.

Apparent mineralocorticoid excess: time of manifestation and complications despite treatment.

Here we describe the case of a patient followed from birth because of a positive family history for apparent mineralocorticoid excess (AME) in an older brother. The patient, a girl, had normal serum electrolyte and blood pressure measurements in the first months after birth. Not until the age of 11 months did she develop anorexia and failure to thrive in combination with hypertension, hypokalemia, and metabolic alkalosis, which are consistent with the diagnosis of AME.

Renal transplantation for fibromuscular dysplasia.

This is the first report that presents renal transplantation after bilateral nephrectomy as the final treatment for severe renovascular hypertension due to fibromuscular dysplasia (FMD). We describe the history of a 1-year-old girl who suffered from renovascular hypertension due to FMD. Imaging revealed multiple bilateral stenoses of the renal artery extending into the distal branches.

Cysteamine restores glutathione redox status in cultured cystinotic proximal tubular epithelial cells.

Recent evidence implies that impaired metabolism of glutathione has a role in the pathogenesis of nephropathic cystinosis. This recessive inherited disorder is characterized by lysosomal cystine accumulation and results in renal Fanconi syndrome progressing to end stage renal disease in the majority of patients. The most common treatment involves intracellular cystine depletion by cysteamine, delaying the development of end stage renal disease by a yet elusive mechanism.

Immunosuppression and renal outcome in congenital and pediatric steroid-resistant nephrotic syndrome.

Background And Objectives: Mutations in podocyte genes are associated with steroid-resistant nephrotic syndrome (SRNS), mostly affecting younger age groups. To date, it is unclear whether these patients benefit from intensified immunosuppression with cyclosporine A (CsA). The aim of this study was to evaluate the influence of podocyte gene defects in congenital nephrotic syndrome (CNS) and pediatric SRNS on the efficacy of CsA therapy and preservation of renal function.

Nephrogenic syndrome of inappropriate antidiuresis.

The nephrogenic syndrome of inappropriate antidiuresis (NSIAD) is a rare, recently recognized disorder in water balance affecting not only infants but also adults. A new molecular mechanism responsible for NSIAD has recently been identified: a gain of function of the arginine vasopressin (AVP) receptor type 2 (V2R), causing the constitutive activation of the receptor. Clinical presentation and laboratory findings of NSIAD resemble those of the syndrome of inappropriate secretion of antidiuretic hormone and consist of hyponatraemia, seizures and the lack of urinary dilution; however, the AVP levels in plasma are undetectable or very low.