[Effect of dexamethasone and spironolactone therapy in calcium and phosphate homeostasis in premature infants with a birth weight under 1,500 g]

Aqueous extract of pomegranate seed attenuates glucocorticoid-induced bone loss and hypercalciuria in mice: A comparative study with alendronate

The present study was performed in order to examine bone loss and calcium homeostasis in mice with glucocorticoid (GC)-induced osteoporosis (GIOP) following treatment with the aqueous extract of pomegranate seed (AE-PS). In addition, a comparative study with alendronate was performed. Biomarkers in the serum and the urine were measured. The tibias, kidney and duodenum were removed in order to measure the levels of bone calcium, protein expression as well as to perform histomorphological analysis of the bone. GC treatment facilitated the induction of hypercalciuria in the mice, and the AE-PS‑treated mice exhibited a greater increase in serum calcium and a decrease in urine calcium. The AE-PS reversed the deleterious effects on the trabecular bone induced by DXM and stimulated bone remodeling, including an increase in bone calcium and alkaline phosphatase‑b (ALP-b) and a decrease in a the critical bone resorption markers C-terminal telopeptide of type I collagen (CTX) and tartrate‑resistant acid phosphatase-5b (TRAP-5b). Hematoxylin and eosin (H&E) staining revealed the increased disconnections and separation between the growth plate and the trabecular bone network as well as the reduction in the trabecular bone mass of the primary and secondary spongiosa throughout the proximal metaphysis of the tibia in the DXM group. Moreover, the decreased protein expression of transient receptor potential vanilloid (TRPV)5, TRPV6 and calbindin‑D9k (CaBP‑9k) was reversed by the AE-PS or alendronate supplementation in the kidneys and the duodenum as well as plasma membrane Ca2+‑ATPase1 (PMCA1) expression in the kidneys of mice with GIOP. There was no marked difference in pharmacological effectiveness between alendronate and the AE-PS. Taken together, these findings suggest that the AE-PS may be an alternative therapy suitable for use in the management of secondary osteoporosis.

Diuretics acting on the distal renal tubule for preterm infants with (or developing) chronic lung disease

BACKGROUND

Lung disease in preterm infants is often complicated with lung edema.

OBJECTIVES

To assess the risks and benefits of diuretics acting on distal segments of the renal tubule (distal diuretics) in preterm infants with or developing chronic lung disease (CLD).

SEARCH STRATEGY

The standard method of the Cochrane Neonatal Review Group were used. Initially, MEDLINE (1966 to November 2001), EMBASE (1974 to November 2001) and the Cochrane Controlled Trials Register (CENTRAL,The Cochrane Library, Issue 4, 2001) were searched. In addition, several abstract books of national and international American and European Societies were hand searched. Updated searches in April 2003, April 2007, and December 2010 did not yield any additional trials.

SELECTION CRITERIA

Included in this analysis are trials in which preterm infants with or developing CLD and at least five days of age were randomly allocated to receive a diuretic acting on the distal renal tubule. Eligible studies needed to assess at least one of the outcome variables defined a priori for this systematic review.

DATA COLLECTION AND ANALYSIS

The standard method for the Cochrane Collaboration described in the Cochrane Collaboration Handbook were used. Two investigators extracted, assessed and coded separately all data for each study. Any disagreement was resolved by discussion. Parallel and cross-over trials were combined. Whenever possible, baseline and final outcome data measured on a continuous scale was transformed into change scores using Follmann's formula.

MAIN RESULTS

Of the six studies fulfilling entry criteria, most focused on pathophysiological parameters and did not assess effects on important clinical outcomes defined in this review, or the potential complications of diuretic therapy.In preterm infants > 3 weeks of age with CLD, a four week treatment with thiazide and spironolactone improved lung compliance and reduced the need for furosemide. A single study showed thiazide and spironolactone decreased the risk of death and tended to decrease the risk for remaining intubated after eight weeks in infants who did not have access to corticosteroids, bronchodilators or aminophylline.

AUTHORS' CONCLUSIONS

In preterm infants > 3 weeks of age with CLD, acute and chronic administration of distal diuretics improve pulmonary mechanics. However, positive effects should be interpreted with caution as the numbers of patients studied are small in surprisingly few randomized controlled trials.

Does citrate prevent nephrocalcinosis in preterm neonates?

Nephrocalcinosis (NC) occurs frequently in preterm neonates. A high U-calcium/citrate is one of the contributing factors to the development of NC. In stone-forming children and adults citrate supplementation is a successful preventive therapy. In this randomized controlled trial the effect of citrate therapy was studied on the development of NC in preterm neonates with a gestational age <32 weeks. Thirty-eight preterm neonates (mean gestational age 29.8 weeks (SD 1.6), mean birth weight 1,300 g (SD 351) were treated with sodium citrate (0.52 mmol/kg/day in four doses) from day 8 of life until at term and 36 preterm neonates (mean gestational age 29.6 weeks (SD 1.6), mean birth weight 1,282 g (SD 256) were not treated. U-calcium, U-creatinine, U-citrate and U-pH were measured at day 7, 14, 21, 28 of life and at term. Renal ultrasonography (US) was performed at term. U-citrate/creatinine and U-pH were significantly higher and U-calcium/citrate was significantly lower in the citrate group at day 14, 21 and 28 compared with the control group (P<0.05). Complications of citrate administration were not encountered, however the incidence of NC was not significantly different in the treated (34%) compared with the control group (44%), P=0.37. Preterm neonates treated with citrate in the first months of life have higher U-citrate/creatinine and lower U-calcium/citrate compared with controls. Sodium citrate therapy in a dosage of 0.52 mmol/kg/day is safe but does not prevent NC. Whether a higher dose or potassium citrate decreases the incidence of NC should be evaluated in further studies.

Diurétiques et prématuré

Diuretics are frequently used in preterm infants in various situations such as patent ductus arteriosus, respiratory distress syndrome, bronchopulmonary dysplasia or neonatal renal insufficiency. However, the beneficial effects reported in the literature are usually transient, without any obvious effect on important parameters such as duration of oxygen dependency, ventilator dependency, length of hospital stay, long-term outcome, or mortality. Moreover, these drugs may induce water-electrolyte disorders especially when used for a long-term period. Thus, we recommend a systematic analysis of the beneficial/risk ratio before any use of these drugs.

Clinical Experience with Spironolactone in Pediatrics

BACKGROUND:

In 2003, the Food and Drug Administration placed spironolactone on its list of drugs needing pediatric studies.

OBJECTIVE:

To describe the use of spironolactone in a large group of children and evaluate its safety, focusing on its effects on potassium.

METHODS:

A prospective observational study was conducted. Patient demographic information was collected, as well as dosing regimens, use of other medications, and potassium concentrations. Patients were grouped by diagnosis. Comparisons were made with unpaired t-tests.

RESULTS:

One hundred consecutive patients were evaluated. The average age was 20.8 months and weight was 9.5 kg. Sixty-two patients had heart disease (HD), 29 had chronic lung disease (CLD), and 9 had other conditions. The initial dose was 1.8 ± 0.7 mg/kg/day. Patients with CLD received a higher dose than those with HD (2 ± 0.8 vs 1.7 ± 0.5 mg/kg/day; p = 0.04). Sixty-six patients received furosemide and 37 received thiazides (12 received both). The average potassium concentration after initiation was 4.3 ± 0.8 mEq/L, with higher values in patients with CLD versus HD (4.7 ± 0.7 vs 4.2 ± 0.7 mEq/L; p = 0.007). Twenty-six patients required potassium supplementation, including 16 with CLD and 8 with HD; no other adverse effects were noted. Average length of treatment was 16 days, with a length of stay of 38 days. Of the 92 patients surviving to discharge, 66 continued on spironolactone.

CONCLUSIONS:

This sample demonstrates that spironolactone is a common component of diuretic regimens in pediatric patients. The only adverse effects were alterations in potassium. While hyperkalemia was more common initially, hypokalemia was more frequent with long-term use. Potassium concentrations should be carefully monitored, particularly in children receiving multiple diuretics. Additional research is needed to define the pharmacokinetics and optimal dosing interval of spironolactone, as well as determine its long-term effects on potassium.

High incidence of nephrocalcinosis in extremely preterm infants treated with dexamethasone

BACKGROUND

The use of postnatal corticosteroids to treat or prevent chronic lung disease is common in very preterm infants. Medullary nephrocalcinosis has been noted as a possible side effect.

OBJECTIVE

This prospective study was designed to assess the incidence of nephrocalcinosis in extremely preterm infants exposed to dexamethasone.

PATIENTS AND METHODS

A prospective study of extremely preterm infants, recruited to a randomized trial of dexamethasone treatment for chronic lung disease, was initiated. Infants had US of the renal tract scheduled on entry into the study, at day 28 and at discharge or at the corrected gestational age of 36 weeks.

RESULTS

Thirty-three infants were enrolled in the study. Birth weight ranged between 440 and 990 g and gestation between 24 and 28 weeks. Nine infants died and six had incomplete data. Because there was no difference in incidence of calcification between those on the short course and those on the long course of dexamethasone, analysis was made on the entire cohort. One infant had nephrocalcinosis at the time of the initial US examination on day 26 of life. By day 28, nephrocalcinosis was present in 31% of those with complete data. By discharge, or corrected gestational age of 36 weeks, US evidence of nephrocalcinosis was present in 15 (83%) of 18 infants. All infants had at least one course of an aminoglycoside antibiotic during the study. All infants had parenteral nutrition. Only four infants received furosemide more regularly than single doses. The longest course was 10 days, received by an infant who did not develop nephrocalcinosis.

CONCLUSION

The incidence of nephrocalcinosis is high in this group of sick, extremely preterm infants. Dexamethasone may be a factor in the development of nephrocalcinosis. Future research should focus on the natural history of nephrocalcinosis in extremely preterm infants.

The use of quantitative ultrasound in assessing bone status in newborn preterm infants

OBJECTIVE

Quantitative ultrasound is increasingly used to assess bone status in adults and children; however, few studies have been carried out in neonates. Our objective was to determine if tibial bone speed of sound (SOS) correlates with gestational age and birth anthropometrics, and if bone SOS is related to maternal factors.

STUDY DESIGN

We prospectively studied 95 preterm infants to assess factors related to bone status as measured by quantitative ultrasound.

RESULTS

We found significant (p< or =0.001) positive correlations between SOS and gestational age, birth weight, length, head circumference and tibial length. There was no significant relationship between SOS and prenatal steroid use, gestational diabetes, pre-eclampsia, race or parity.

CONCLUSIONS

Quantitative ultrasound is an easy to use and inexpensive tool for assessing bone status in preterm neonates. Tibial SOS correlated with gestational age and birth anthropometrics, and was not related by few maternal factors.

Calcium, phosphorus and magnesium balance: FM 85 fortification of human milk does not meet mineral needs of extremely low birthweight infants

OBJECTIVE

Extremely low birthweight (<1000 g) infants are growing rapidly and their nutritional requirements for calcium, phosphorus, magnesium are high.

DESIGN

Prospective, mineral balance.

SETTING

The study was carried out at the Department of Neonatology, Virchow-Hospital, Charité Berlin and the Department of Molecular Trace Element Research, Hahn-Meitner-Institute Berlin.

SUBJECTS

Nineteen infants <1000 g birthweight were admitted, nine infants dropped out and 10 infants (birthweight 730-995 g), fed fortified human milk were included.

INTERVENTION

We collected infant's urine and feces for 72 h, a sample of human milk and infant's blood at 7 and 12 weeks of age. Elements were measured by inductively coupled plasma atomic emission spectrophotometry.

RESULTS

Mean (s.d.) mineral concentration in milk was low especially at 12 weeks: calcium 9.88 (+/-3.58) mmol/l, phosphorus 7.02 (+/-3.81) mmol/l, magnesium 1.59 (+/-0.54) mmol/l. Calcium retention was minimal or negative during the study, whereas phosphorus and magnesium balances were positive. Caffeine and diuretics increased mineral excretion. Serum alkaline phosphatase was mostly <800 U/l, and 162 U/l in one infant with zinc deficiency at 12 weeks. Alkaline phosphatase correlated with absorption and retention of phosphorus, and with longitudinal growth.

CONCLUSIONS

Infants <1000 g have high nutritional needs for calcium, phosphorus and magnesium, which are not met by a human milk fortifier widely used in Europe. Controlled trials are needed to assess requirements, duration and risks of mineral supplementation.

Diuretics acting on the distal renal tubule for preterm infants with (or developing) chronic lung disease

OBJECTIVES

The aim of this review is to assess the risks and benefits of diuretics acting on distal segments of the renal tubule (distal diuretics) in preterm infants with or developing chronic lung disease (CLD). Primary objectives are to assess changes in need for oxygen or ventilatory support and effects on long-term outcome, and secondary objectives are to assess changes in pulmonary mechanics and potential complications of therapy.

SEARCH STRATEGY

We used the standard method of the Cochrane Neonatal Review Group. We searched MEDLINE (1966-November 2001), EMBASE (1974-November 2001) and the Cochrane Controlled Trials Register (CCTR) (Cochrane Library Issue 4, 2001). In addition, we hand searched several abstract books of national and international American and European Societies.

SELECTION CRITERIA

We included in this analysis trials in which preterm infants with or developing CLD and at least five days of age were all randomly allocated to receive a distal diuretic (i.e., a diuretic acting on the distal renal tubule). Eligible studies needed to assess at least one of the outcome variables defined a priori for this systematic review. Primary outcome variables included changes in need for respiratory support and oxygen supplementation, mortality, bronchopulmonary dysplasia (BPD), death or BPD, chronic lung disease at 36 weeks of postconceptional age (gestational age + postnatal age), length of stay, and number of rehospitalizations during the first year of life. Secondary outcome variables included pulmonary mechanics and potential complications of therapy.

DATA COLLECTION AND ANALYSIS

We used the standard method for the Cochrane Collaboration which is described in the Cochrane Collaboration Handbook. Two investigators extracted, assessed and coded separately all data for each study, using a form that was designed specifically for this review. Any disagreement was resolved by discussion. We combined parallel and cross-over trials and, whenever possible, transformed baseline and final outcome data measured on a continuous scale into change scores using Follmann's formula.

MAIN RESULTS

Of six studies fulfilling entry criteria, most focused on pathophysiological parameters and did not assess effects on important clinical outcomes defined in this review, or the potential complications of diuretic therapy. In preterm infants > 3 weeks of age with CLD, a four-week treatment with thiazide and spironolactone improved lung compliance and reduced the need for furosemide. Thiazide and spironolactone decreased the risk of death and tended to decrease the risk for lack of extubation after 8 weeks in intubated infants who did not have access to corticosteroids, bronchodilators or aminophylline. However, there is little or no evidence to support any benefit of diuretic administration on need for ventilatory support, length of hospital stay, or long-term outcome in patients receiving current therapy. There is no evidence to support the hypothesis that adding spironolactone to thiazide or that adding metolazone to furosemide improves the outcome of preterm infants with CLD.

REVIEWER'S CONCLUSIONS

In preterm infants > 3 weeks of age with CLD, acute and chronic administration of distal diuretics improve pulmonary mechanics. Studies are needed to assess (1) whether thiazide administration improves mortality, duration of oxygen dependency, ventilator dependency, length of hospital stay and long-term outcome in patients exposed to corticosteroids and bronchodilators (2) whether adding spironolactone to thiazides or adding metolazone to furosemide has any beneficial effect.

Nephrocalcinosis in preterm babies

OBJECTIVES

To determine prospectively the incidence and cause of nephrocalcinosis in preterm infants.

STUDY DESIGN

Inborn babies of gestation less than 32 weeks or birth weight less than 1500 g were eligible to be entered into a prospective observational study. Two renal ultrasound scans were performed, the first at 1 month postnatal age and the second at term or discharge. Data were collected on gestation, birth weight, sex, race, family history of renal calculi, oliguria on first day, respiratory support (ventilation, steroid, and oxygen dependency), and use of nephrotoxic drugs (gentamicin, vancomycin, and frusemide). Intake of fluid, calcium, and phosphate and plasma urea, creatinine, calcium, and phosphate were recorded for the first 6 weeks of life. Random urinary calcium/creatinine, oxalate/creatinine, and urate/creatinine ratios and tubular absorption of phosphate were measured once at term.

RESULTS

A total of 101 preterm infants were studied. Twenty three (23%) had abnormal ultrasound scans. Sixteen (16%) had nephrocalcinosis. On univariate analysis, gestational age, male sex, duration of ventilation, oxygen dependency, duration and frequency of gentamicin treatment, toxic gentamicin/vancomycin levels, and postnatal dexamethasone were significantly associated with nephrocalcinosis. In addition, babies with nephrocalcinosis had a lower intake of fluid, calcium, and phosphate, longer duration of total parenteral nutrition, and higher urinary oxalate/creatinine and urate/creatinine ratios than infants who did not have the condition. There was also a significant association with plasma urea and creatinine but not with plasma calcium or phosphate or urinary calcium. Multivariate analysis showed that the strongest predictors of nephrocalcinosis were duration of ventilation, toxic gentamicin/vancomycin levels, low fluid intake, and male sex.

CONCLUSION

16% of babies born at less than 32 weeks gestation developed nephrocalcinosis. The multifactorial origin, in particular, the association with extreme prematurity and severity of respiratory disease, is confirmed. In addition, an association with male sex, frequency and duration of gentamicin use, and high urinary oxalate and urate excretion is shown.

Etiology of nephrocalcinosis in preterm neonates: association of nutritional intake and urinary parameters

BACKGROUND

Nephrocalcinosis (NC) in preterm neonates has been described frequently, and small-scale studies suggest an unfavorable effect on renal function. The etiologic factors have not yet been fully clarified. We performed a prospective observational study to identify factors that influence the development of NC.

METHODS

The study population consisted of 215 preterm neonates with a gestational age <32 weeks. Clinical characteristics and intake in the first four weeks of calcium, phosphorus, vitamin D, protein, and ascorbic acid were noted. Serum calcium, phosphate, vitamin D, magnesium, uric acid, creatinine, urea and urinary calcium, phosphate, oxalate, citrate, magnesium, uric acid, and creatinine were assessed at four weeks of age and at term. Renal ultrasonography (US) was performed at four weeks and at term. At term was defined as a postconceptional age of 38 to 42 weeks.

RESULTS

NC was diagnosed by means of US in 33% at four weeks and in 41% at term. Patients with NC at four weeks had a significantly higher mean intake of calcium (P < 0.05), phosphorus (P < 0.05), and ascorbic acid (P < 0.01) than patients without NC. They had a higher mean serum calcium (2.55 vs. 2.46 mmol/L, P < 0.01) and a higher mean urinary calcium/creatinine ratio (2.6 vs. 2.1 mmol/mmol, P < 0.05). Patients with NC at term had a lower birth weight (1142 vs. 1260 g, P < 0.05) and a lower gestational age (28.8 vs. 29.4 weeks, P < 0.05), were treated significantly longer with furosemide, dexamethasone, theophylline, and thiazides, developed chronic lung disease more frequently (40 vs. 16%, P < 0.001), and had a higher mean urinary calcium/creatinine ratio (2.7 vs. 2.3 mmol/mmol, P < 0.05) and a lower mean urinary citrate/calcium ratio (1.1 vs. 1.7 mmol/mmol, P = 0.005).

CONCLUSIONS

NC develops as a result of an imbalance between stone-inhibiting and stone-promoting factors. A high intake of calcium, phosphorus, and ascorbic acid, a low urinary citrate/calcium ratio, a high urinary calcium/creatinine ratio, immaturity, and medication to prevent or treat chronic lung disease with hypercalciuric side effects appear to contribute to the high incidence of NC in preterm neonates.