Antibiotics and renal branching morphogenesis: comparison of toxicities

Abstract

Background: Many premature born neonates receive antibiotic drugs to treat infections, which are applied during active nephrogenesis. We studied the impact of clinical concentrations of gentamicin and alternatives, ceftazidime and meropenem, on ureteric branching. Methods: Mice metanephroi were dissected at embryonic day 13 and cultured in media with or without various concentrations of gentamicin, ceftazidime, or meropenem. Zero and 24 h kidney size were assessed by surface area measurements, and the ureteric tree was visualized by whole mount staining and confocal microscopy. Branching was evaluated by counting and gene expression levels of Wt1, Sox9, Bmp7, Fgf8, and Gdnf were investigated. results: A concentration of 2,000 μmol/l ceftazidime impaired ureteric development. In addition, a 4.5-fold and a 2.5-fold downregulation was noted in Fgf8 and Gdnf, respectively. No adverse effects were noted after gentamicin or meropenem treatment. No relationship was noted between surface area expansion and ureteric bud formation, but surface area at explantation related to bud count after 24 h of culture. conclusion: Ceftazidime, but not gentamicin or meropenem reduced ureteric branching in mice and suggest a role for Fgf8 and Gdnf in its mechanism. Metanephros surface area measurements can be used to reduce intra-and inter-litter variation. k idney development, leading to the formation of nephrons, starts around the 5th wk of gestation and terminates before term birth, around the 34th-36th wk of gestation. Many factors have been described to disturb this developmental process, leading to long-term problems such as hypertension and chronic kidney disease (1).One such disturbing factor may be the use of (nephrotoxic) drugs during kidney development, such as in pregnant women or neonates born before termination of nephrogenesis. Gentamicin, as well as other aminoglycosides, is widely used as part of the first line treatment of (suspected) bacterial infection in neonates to combat Gram-negative infections. Based on data from the Netherlands Perinatal Registry, 62% of neonates born before 32 wk, who can be considered the most vulnerable group, are treated with aminoglycosides (2). However, due to the fact that gentamicin is classified as a nephrotoxic drug, controversy remains on its safety as aminoglycosides have been shown to disturb kidney development and lead to a reduced nephron number in some experimental animals (3-6) and organ culture studies (7).The aim of our research was to study the impact of antibiotic treatments on nephrogenesis in a model of early nephrogenesis. Gentamicin was studied as well as clinically relevant, alternative drug treatments to compare the toxic potentials of these drugs in a clinical dose range. As alternative treatments, we chose a third generation cephalosporin, ceftazidime, and the carbapenem meropenem. These two drugs both have properties to deal with Gram-negative bacteria and have different mechanisms of action compared to gentamicin. Although beta-lactams have their own potencies to...

Early postnatal gentamicin and ceftazidime treatment in normal and food restricted neonatal wistar rats: Implications for kidney development

“…Whether potential effects on kidney development would be more C max or AUC driven is currently unknown. The ceftazidime toxicity described by our group in an ex vivo model (Bueters et al, 2014) was not confirmed in this in vivo study based on unaffected glomerular numbers. The nephrogenesis inhibiting effect may, therefore, be limited to the stage of very early kidney development, which holds more relevance to pregnant women than to preterm born neonates.…”

“…PND 8 left kidneys were pulverized in deep frozen state by a microdismembrator (Sartorius‐Stedim, the Netherlands), processed according to methods earlier described (Bueters et al, ), and 1 μg of RNA was used in a subsequent reverse transcriptase reaction. Quantitative PCR (qPCR) was performed on a Bio‐Rad CFX96 using gene expression mix and hydrolysis probes (Table ) as ordered from Applied Biosystems (Pleasanton, CA) or Biolegio (Nijmegen, the Netherlands).…”

“…An alternative for gentamicin treatment in daily clinical practice may be found in ceftazidime, a drug from the cephalosporin drug class. Ceftazidime is a less potent drug regarding acute nephrotoxicity (Tune, ), but one of our earlier studies identified it as a possible kidney development disruptor (Bueters et al, ). In that study, ceftazidime affected Gdnf and Fgf8 , two important genes involved in the ureteric bud growth process of kidney development.…”

“…Indeed some studies have shown aminoglycosides to disturb kidney development in vivo or ex vivo (Gilbert et al, 1987(Gilbert et al, , 1991(Gilbert et al, , 1996Schwedler et al, 1999); however, other in vivo and ex vivo studies could not find an effect (Kent et al, 2009;Bueters et al, 2014). In the studies that did find a toxic effect, dose levels were high and one can argue that the level of acute toxicity had already been reached.…”

Quantitative clinical pharmacology practice for optimal use of antibiotics during the neonatal period

“…Term neonates have a rapid increase in GFR during the first 2 weeks of life and reach adult values by the first year of life, while premature infants show similar trends with a slower initial rise in GFR because nephrogenesis is not completed before 34 weeks of gestation [28,29]. Furthermore, exposure to drugs during the neonatal period might jeopardize the full development of the potential pool of glomeruli and that might have consequences later in life [30,31]. Interestingly, the postnatal maturation results in at least a twofold increase in GFR in the first weeks of life and is due to shifts in intra-renal blood flow [24].…”