SummaryMany nephrotoxic effects of drugs have been described, whereas the effect on renal development has received less attention. Nephrogenesis ceases at approximately 36 weeks of gestation, indicating that drugs administered to pregnant women and to preterm-born neonates may influence kidney development. Such an effect on renal development may lead to a wide spectrum of renal malformations (congenital anomalies of the kidney and urinary tract [CAKUT]), ranging from renal agenesis to a reduced nephron number. Any of these anomalies may have long-term sequelae, and CAKUT is the primary cause for renal replacement therapy in childhood. This review focuses on research into the effect of drug treatment during active nephrogenesis during pregnancy and in preterm-born infants. Because the effects of many widely used drugs have not been unraveled thus far, more research is needed to study the effect on renal development and long-term renal sequelae after drug treatment during nephrogenesis.

The kidney plays a central role in the clearance of drugs. However, renal drug handling entails more than glomerular filtration and includes tubular excretion and reabsorption, and intracellular metabolization by cellular enzyme systems, such as the Cytochrome P450 isoenzymes. All these processes show maturation from birth onwards, which is one of the reasons why drug dosing in children is not simply similar to dosing in small adults. As kidney development normally finishes around the 36th week of gestation, being born prematurely will result in even more immature renal drug handling. Environmental effects, such as extra-uterine growth restriction, sepsis, asphyxia, or drug treatments like caffeine, aminoglycosides, or non-steroidal anti-inflammatory drugs, may further hamper drug handling in the kidney. Dosing in preterm neonates is therefore dependent on many factors that need to be taken into account. Drug treatment may significantly hamper postnatal kidney development in preterm neonates, just like renal immaturity has an impact on drug handling. The restricted kidney development results in a lower number of nephrons that may have several long-term sequelae, such as hypertension, albuminuria, and renal failure. This review focuses on the interplay between drugs and the kidney in premature neonates.

The kidneys play an important role in many processes, including urine formation, water conservation, acid-base equilibrium, and elimination of waste. The anatomic and functional development of the kidney has different maturation time points in humans versus animals, with critical differences between species in maturation before and after birth. Absorption, distribution, metabolism, and excretion (ADME) of drugs vary depending on age and maturation, which will lead to differences in toxicity and efficacy. When neonate/ juvenile laboratory animal studies are designed, a thorough knowledge of the differences in kidney development between newborns/ children and laboratory animals is essential. The human and laboratory animal data must be combined to obtain a more complete picture of the development in the kidneys around the neonatal period and the complexity of ADME in newborns and children. This review examines the ontogeny and cross-species differences in ADME processes in the developing kidney in preterm and term laboratory animals and children. It provides an overview of insights into ADME functionality in the kidney by identifying what is currently known and which gaps still exist. Currently important renal function properties such as glomerular filtration rate, renal blood flow, and ability to concentrate are generally well known, while detailed knowledge about transporter and metabolism maturation is growing but is still lacking. Preclinical data in those properties is limited to rodents and generally covers only the expression levels of transporter or enzyme-encoding genes. More knowledge on a functional level is needed to predict the kinetics and toxicity in neonate/juvenile toxicity and efficacy studies. SIGNIFICANCE STATEMENTThis review provides insight in cross-species developmental differences of absorption, distribution, metabolism, and excretion properties in the kidney, which should be considered in neonate/juvenile study interpretation, hypotheses generation, and experimental design.dependent on the specialized subcellular structural and functional properties of renal tubule epithelium, including their various transporters, metabolic activity, and membrane integrity. Therefore, the development and maturation of these processes in pediatric patients or in animals can have a profound effect on the disposition and fate of administered drug therapies that depend on the kidney for filtration, uptake, secretion, and/or metabolism.

Appropriate control of cell death is a fundamental biological process which is frequently dysregulated during tumor development and therapeutic resistance. Apoptosis is a form of regulated cell death initiated by either the extracellular environment (extrinsic) or following internal cellular damage (intrinsic). It is controlled by the BCL-2 family which includes anti-apoptotic regulators like BCL-2, BCL-XL and MCL-1 that bind and sequester various pro-apoptotic BH3-only proteins (BIM, BAD, BID, NOXA, PUMA, etc.), and the pro-apoptotic effectors (BAK, BAX, etc.) responsible for mitochondrial pore formation and MOMP (mitochondrial outer membrane permeabilization). MOMP results in intermembrane space protein release, leading to caspase activation in an irreversible path to programmed cell death. Of the anti-apoptotic regulators, MCL-1 is one of the most frequently and highly amplified genes in human cancers such as myeloid leukemia making it a compelling therapeutic target. Since BCL-2 proteins interact through protein-protein interactions, they have long been elusive targets. The success of selective BCL-2 protein inhibitor Venetoclax in the treatment of various hematological cancers, however spurred interest in MCL-1 as an oncology target. Using structure-based drug design, major breakthroughs were made in the development of MCL-1 inhibitors, with several candidates entering clinical studies in the past five years. JNJ-4355, a highly potent 1,4-indolyl macrocycle (MCL-1 Ki = 18 pM, Cell (MOLP8) AC50 = 8.7 nM) was optimized to address shortcomings from first generation MCL-1 inhibitors: it has improved physicochemical properties (CHI LogD7.4 = 2.35, EPSA = 151 Å2), resulting in greatly improved equilibrium solubility (3.14 mM in buffer pH 7) and reduced protein binding (99.93%). JNJ-4355 showed promising in vitro potency data in cancer cell lines and AML patient-derived samples (cell killing AC50 0.29-75 nM in 25/27 evaluable samples). In vivo MCL-1:BAK complex disruption was confirmed in a mouse MOLM13 (AML) xenograft. Efficacy was demonstrated in a mouse MOLP8 (multiple myeloma) xenograft resulting in complete tumor regression after a single IV dose of JNJ-4355. Citation Format: Frederik J. Rombouts, Lento William, Ingrid Velter, Ann Vos, Aldo Peschiulli, Reuillon Tristan, Maria Dominguez Blanco, Matthieu Jouffroy, Lisa McQueen, Helena Steyvers, Mariette Bekkers, Cristina Altrocchi, Beth Pietrak, Seong Joo Koo, Lawrence Szewczuk, David Walker, Kathryn Packman, Ruud Bueters, Petra Vinken, Amy Johnson, Ricardo Attar, Ulrike Philippar. In pursuit of MCL-1 inhibitors with improved therapeutic window for the treatment of hematological malignancies: Discovery of JNJ-4355 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2133.

Background: Renal size is often used as a marker for nephron numbers as estimation of glomerular numbers is not yet possible in vivo. However, the validity of an association between the two is questionable. As a proper marker for nephron number in an individual is needed in clinical practice, this study was designed to assess the association between renal size and nephron numbers. Methods: An individual patient data meta-analysis was performed on data retrieved with a PubMed and Embase search. Only studies were included that described individual human data on kidney size and nephron numbers determined by stereology, the gold standard methodology to estimate nephron numbers. As renal size increases until the end of puberty, and nephron numbers decline after the age of 60 years, only data from individuals aged 18-60 years without renal disease were included. Results: Six papers were identified that provided data on renal weight and nephron numbers from 114 individuals. Backward linear regression identified kidney weight and race as the only 2 significant factors explaining nephron numbers (R square 0.085, p=0.007). Controlling for race, there was a significant correlation between nephron number and kidney weight (r=0.231, r square=0.053, p=0.01). Conclusion: These data indicate that only ∼5% of the variation in nephron numbers is explained by differences in renal size. Renal size in adulthood should not be used as a marker for nephron numbers in an individual.

Avoidance of apoptosis is critical for the development and sustained growth of tumors. The pro-survival protein myeloid cell leukemia 1 (Mcl-1) is an anti-apoptotic member of the Bcl-2 family of proteins which is overexpressed in many cancers. Upregulation of Mcl-1 in human cancers is associated with high tumor grade, poor survival, and resistance to chemotherapy. Therefore, pharmacological inhibition of Mcl-1 is regarded as an attractive approach to treating relapsed or refractory malignancies. Herein, we disclose the design, synthesis, optimization, and early preclinical evaluation of a potent and selective small-molecule inhibitor of Mcl-1. Our exploratory design tactics focused on structural modifications which improve the potency and physicochemical properties of the inhibitor while minimizing the risk of functional cardiotoxicity. Despite being in the "non-Lipinski" beyond-Rule-of-Five property space, the developed compound benefits from exquisite oral bioavailability in vivo and induces potent pharmacodynamic inhibition of Mcl-1 in a mouse xenograft model.

A clinical Ibuprofen dose showed potential to inhibit kidney development in neonatal rats. FR did not modulate these effects.

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...