Indomethacin treatment decreases renal blood flow velocity in human neonates

Nifuroxazide attenuates indomethacin-induced renal injury by upregulating Nrf2/HO-1 and cytoglobin and suppressing NADPH-oxidase, NF-κB, and JAK-1/STAT3 signals

Indomethacin (INDO) is an NSAID with remarkable efficacy and widespread utilization for alleviating pain. Nevertheless, renal function impairment is an adverse reaction linked to INDO usage. Nifuroxazide (NFX), an oral nitrofuran antibiotic, is frequently employed as an intestinal anti-infective agent. Our study aimed to investigate the renoprotective effects of NFX against INDO-induced nephrotoxicity and explore the protection mechanisms. Four groups of rats were allocated to (I) the normal control, (II) the NFX-treated (50 mg/kg), (III) INDO control (20 mg/kg), and (IV) NFX + INDO. NFX attenuates renal impairment in INDO-induced renal injury, proved by decreasing serum levels of urea, creatinine, uric acid, and NGAL while the albumin was elevated. NFX mitigates renal oxidative stress by decreasing MDA levels and restoring the antioxidants' GSH and SOD levels mediated by upregulating Nrf2, HO-1, and cytoglobin pathways. NFX mitigated renal inflammation and effectively decreased MPO, IL-1β, and TNF-α levels in the rat's kidney mediated by significant downregulation of NADPH-oxidase and NF-κB expression and suppression of JAK-1 and STAT3 phosphorylation. NFX mitigates renal apoptosis by decreasing the expression of cleaved caspase-3 expression. In conclusion, NFX treatment prevents INDO nephrotoxicity by regulating Nrf2/HO-1, cytoglobin, NADPH-oxidase, NF-κB, and JAK-1/STAT3 signals.

Organic Anion Transporter 2: An Enigmatic Human Solute Carrier

As a member of the solute carrier 22A (SLC22A) family, organic anion transporter 2 (OAT2; SLC22A7) is emerging as an important drug transporter because of its expression in both the liver and kidney, two major eliminating organs, and its ability to transport not only a wide variety of xenobiotics but also numerous physiologically important endogenous compounds, like creatinine and cGMP. However, OAT2 has received relatively little attention compared with other OATs and solute carriers (SLCs), like organic cation transporters, sodium-dependent taurocholate cotransporting polypeptide, multidrug and toxin extrusion proteins, and organic anion-transporting polypeptides. Overall, the literature describing OAT2 is rapidly evolving, with numerous publications contradicting each other regarding the transport mechanism, tissue distribution, and transport of creatinine and cGMP, two important endogenous OAT2 substrates. Despite its status as a liver and kidney SLC, tools for assessing its activity and inhibition are lacking, and its role in drug disposition and elimination remains to be defined. The current review focuses on the available and emerging literature describing OAT2. We envision that OAT2 will gain more prominence as its expression, substrate, and inhibitor profile is investigated further and compared with other SLCs.

Characterization of Organic Anion Transporter 2 (SLC22A7): A Highly Efficient Transporter for Creatinine and Species-Dependent Renal Tubular Expression

The contribution of organic anion transporter OAT2 (SLC22A7) to the renal tubular secretion of creatinine and its exact localization in the kidney are reportedly controversial. In the present investigation, the transport of creatinine was assessed in human embryonic kidney (HEK) cells that stably expressed human OAT2 (OAT2-HEK) and isolated human renal proximal tubule cells (HRPTCs). The tubular localization of OAT2 in human, monkey, and rat kidney was characterized. The overexpression of OAT2 significantly enhanced the uptake of creatinine in OAT2-HEK cells. Under physiologic conditions (creatinine concentrations of 41.2 and 123.5 µM), the initial rate of OAT2-mediated creatinine transport was approximately 11-, 80-, and 80-fold higher than OCT2, multidrug and toxin extrusion protein (MATE)1, and MATE2K, respectively, resulting in approximately 37-, 1850-, and 80-fold increase of the intrinsic transport clearance when normalized to the transporter protein concentrations. Creatinine intracellular uptake and transcellular transport in HRPTCs were decreased in the presence of 50 µM bromosulfophthalein and 100 µM indomethacin, which inhibited OAT2 more potently than other known creatinine transporters, OCT2 and multidrug and toxin extrusion proteins MATE1 and MATE2K (IC50: 1.3 µM vs. > 100 µM and 2.1 µM vs. > 200 µM for bromosulfophthalein and indomethacin, respectively) Immunohistochemistry analysis showed that OAT2 protein was localized to both basolateral and apical membranes of human and cynomolgus monkey renal proximal tubules, but appeared only on the apical membrane of rat proximal tubules. Collectively, the findings revealed the important role of OAT2 in renal secretion and possible reabsorption of creatinine and suggested a molecular basis for potential species difference in the transporter handling of creatinine.

Long-term renal consequences of preterm birth

The normal development of the kidney may be affected by several factors, including abnormalities in placental function, resulting in fetal growth restriction, exposure to maternal disease states, including hypertension and diabetes, antenatal steroids, chorioamnionitis, and preterm delivery. After preterm birth, several further insults may occur that may influence nephrogenesis and renal health, including exposure to nephrotoxic medications, postnatal growth failure, and obesity after growth restriction. In this review article, common clinical neonatal scenarios are used to highlight these renal risk factors, and the animal and human evidence on which these risk factors are based are discussed.

Effects of prophylactic indomethacin on renal and intestinal blood flows in premature infants

BACKGROUND

Prophylactic indomethacin reduces severe intraventricular hemorrhage and symptomatic patent ductus arteriosus in premature infants. The purpose of this study was to investigate the effects of prophylactic low-dose indomethacin on renal and intestinal blood flow.

METHODS

Subjects were 19 extremely low-birthweight infants admitted to our hospital and enrolled in a multicenter randomized control trial to study the efficacy and complications of prophylactic low-dose indomethacin in the reduction of severe intraventricular hemorrhage and patent ductus arteriosus (indomethacin and placebo groups, ten and nine infants, respectively). We measured blood flow velocity in the right renal artery (right RA) and superior mesenteric artery (SMA) with pulsed Doppler ultrasound before and after the administration of the first dose of 0.1 mg/kg indomethacin or placebo.

RESULTS

End-diastolic blood flow velocity (EDV) in the right RA and SMA increased significantly after the administration of indomethacin (P = 0.0414 and 0.0284, respectively), although the time-averaged mean blood flow velocity (TAV) did not change significantly in either artery. In the placebo group, the pre- and postadministration values for TAV and EDV in the right RA and SMA did not differ. Neither group showed a significant change in the relative vascular resistance (mean blood pressure/TAV) in the right RA or SMA. EDV in the left pulmonary artery was significantly reduced only after the administration of indomethacin (P = 0.0284).

CONCLUSIONS

Prophylactic low-dose indomethacin increases the diastolic blood flow in the RA and SMA via a reduction in the ductal shunt volume, with no change in the regional vascular resistance.

Effects of ibuprofen treatment on the developing preterm baboon kidney

Preterm neonates are commonly exposed postnatally to pharmacological treatments for a patent ductus arteriosus. Exposure of the developing kidney to nephrotoxic medications may adversely impact renal development. This study aimed to determine the effect of early postnatal ibuprofen treatment, both alone and in combination with a nitric oxide synthase inhibitor (NOSi), on renal development and morphology. Baboon neonates were delivered prematurely at 125-day (125d) gestation (term = 185d) and were euthanized at birth or postnatal day 6. Neonates were divided into four groups: 125d gestational controls (n = 8), Untreated (n = 8), Ibuprofen (n = 6), and ibuprofen (Ibu)+NOSi (n = 4). Animals in the Ibuprofen and Ibu+NOSi groups received five doses of ibuprofen, with the Ibuprofen+NOSi animals additionally administered a NOS inhibitor (N(G)-monomethyl-l-arginine). There was no difference among groups in body weight, kidney weight, or glomerular generation number. Nephrogenic zone width was significantly reduced in the Ibuprofen group (123.5 ± 7.4 μm) compared with the 125d gestational control (176.1 ± 6.9 μm) and Untreated animals (169.7 ± 78.8 μm). In the Ibu+NOSi group, nephrogenic zone width averaged 152.7 ± 3.9 μm, which was not significantly different from any other group. Morphologically abnormal glomeruli were present at a range of 0.0-22.9% in the Untreated group, 0.0-6.1% in the Ibuprofen group, and 0.0-1.4% in the Ibu+NOSi group. In conclusion, early postnatal ibuprofen exposure is associated with a reduced nephrogenic zone width, which may suggest the early cessation of nephrogenesis following treatment. Ultimately, this may impact the number of nephrons formed in the preterm kidney.

Effects of ibuprofen treatment on the developing preterm baboon kidney

Preterm neonates are commonly exposed postnatally to pharmacological treatments for a patent ductus arteriosus. Exposure of the developing kidney to nephrotoxic medications may adversely impact renal development. This study aimed to determine the effect of early postnatal ibuprofen treatment, both alone and in combination with a nitric oxide synthase inhibitor (NOSi), on renal development and morphology. Baboon neonates were delivered prematurely at 125-day (125d) gestation (term = 185d) and were euthanized at birth or postnatal day 6. Neonates were divided into four groups: 125d gestational controls (n = 8), Untreated (n = 8), Ibuprofen (n = 6), and ibuprofen (Ibu)+NOSi (n = 4). Animals in the Ibuprofen and Ibu+NOSi groups received five doses of ibuprofen, with the Ibuprofen+NOSi animals additionally administered a NOS inhibitor (N(G)-monomethyl-l-arginine). There was no difference among groups in body weight, kidney weight, or glomerular generation number. Nephrogenic zone width was significantly reduced in the Ibuprofen group (123.5 ± 7.4 μm) compared with the 125d gestational control (176.1 ± 6.9 μm) and Untreated animals (169.7 ± 78.8 μm). In the Ibu+NOSi group, nephrogenic zone width averaged 152.7 ± 3.9 μm, which was not significantly different from any other group. Morphologically abnormal glomeruli were present at a range of 0.0-22.9% in the Untreated group, 0.0-6.1% in the Ibuprofen group, and 0.0-1.4% in the Ibu+NOSi group. In conclusion, early postnatal ibuprofen exposure is associated with a reduced nephrogenic zone width, which may suggest the early cessation of nephrogenesis following treatment. Ultimately, this may impact the number of nephrons formed in the preterm kidney.

Preterm birth and the kidney: implications for long-term renal health

Although the majority of preterm neonates now survive infancy, there is emerging epidemiological evidence to demonstrate that individuals born preterm exhibit an elevated risk for the development of hypertension and renal impairment later in life, thus supporting the developmental origins of health and disease hypothesis. The increased risk may potentially be attributed to a negative impact of preterm birth on nephron endowment. Indeed, at the time when most preterm neonates are delivered, nephrogenesis in the kidney is still ongoing with the majority of nephrons normally formed during the third trimester of pregnancy. A number of clinical studies have provided evidence of altered renal function during the neonatal period, but to date there have been limited studies describing the consequences of preterm birth on kidney structure. Importantly, studies in the preterm baboon have shown that nephrogenesis is clearly ongoing following preterm birth; however, the presence of abnormal glomeruli (up to 18% in some cases) is of concern. Similar glomerular abnormalities have been described in autopsied preterm infants. Prenatal and postnatal factors such as exposure to certain medications, hyperoxia and intrauterine and/or extrauterine growth restriction are likely to have a significant influence on nephrogenesis and final nephron endowment. Further studies are required to determine the factors contributing to renal maldevelopment and to identify potential interventional strategies to maximize nephron endowment at the start of life, thereby optimizing long-term renal health for preterm individuals.

Smokers report more psoriasis, but not atopic dermatitis or hand eczema: results from a Norwegian population survey among adults

BACKGROUND

Many reports indicate that skin diseases are affected by lifestyle factors.

OBJECTIVE

To examine the relationship between reported skin diagnoses, smoking and alcohol consumption in an urban population.

METHODS

Cross-sectional questionnaire-based health study among 18,747 adults in Oslo.

RESULTS

For current smokers, odds ratio for reporting psoriasis was 1.49 (95% CI 1.11-2.00) for males, and 1.48 (95% CI 1.15-1.91) for females, as compared to never smokers. There was no association between reported atopic dermatitis or hand eczema and smoking. High consumption of cigarettes was associated with an increased reporting of psoriasis in men, but not women. Reporting drinking alcohol 4-7 times per week was crudely associated with reporting psoriasis in men, but not in the adjusted model.

CONCLUSION

Cigarette smoking was associated with reported psoriasis, but not with atopic dermatitis or hand eczema.

Management of the neonate with patent ductus arteriosus

Care of the preterm infant with a suspected or confirmed diagnosis of patent ductus arteriosus (PDA) is a frequent challenge for the neonatal nurse. Management of term infants with cardiac lesions dependent upon a PDA can be even more challenging. It is vital for neonatal nurses to understand the normal cardiovascular and pulmonary changes that occur at birth so they can anticipate pathological processes influencing the clinical course of an infant with a PDA. In addition, knowledge of current and effective treatment approaches is essential to providing optimal care for these vulnerable infants, as well as in guiding their parents. The purpose of this article is to review current information about PDA, including physiology, pathophysiology, pharmacological approaches, surgical considerations, complications and outcomes, parental support, and areas for future research.

Nonsteroidal anti-inflammatory agents in neonates

The use of NSAIDs has become routine for adults and children in the management of pain. NSAIDs (other than aspirin [acetylsalicylic acid]) are also enjoying greater popularity as antipyretics since the recognition of Reye's syndrome's putative association with aspirin. In neonates, NSAIDs have been used for many years in an attempt to pharmacologically close the ductus arteriosus. This review examines the various NSAIDs and their potential and real applications in the neonatal population. For completeness, acetaminophen (paracetamol), which has weak NSAID activity and is a widely used analgesic and antipyretic in this patient group, was also included. The prostaglandin system is important for healthy development, and conversely there are unique risks posed by pharmacologic interference with this system in the neonatal period. The prostanoid system in neonates has the capacity to modulate nociception, but comes at the expense of interfering with nearly every organ system. Physiologic effects of inhibition of prostaglandin synthesis applicable to neonates include disruption of the sleep cycle, increased risk of pulmonary hypertension, alterations in cerebral blood flow, decreased renal function, disrupted thermoregulation, and alterations in hemostasis balance, among others. Prostaglandins are also important for the normal development of the central nervous, cardiovascular, and renal systems, and there is evidence that the proper genesis of these systems may be adversely effected by NSAID exposure in utero and in the neonatal period. Gastrointestinal adverse effects have provided the impetus for the development and marketing of selective cyclo-oxygenase type 2 (COX-2) inhibitors. These agents' reputation for safety in adults may not be applicable to neonates. COX-2 is involved in the development of several organ systems, and its inhibition may induce a prothrombotic state. The advent of parenteral formulations of cyclo-oxygenase inhibitors, including COX-2-selective agents, increases the therapeutic flexibility of NSAIDs. However, objective data on the safety of these agents have not kept pace with their clinical availability.

Indomethacin for asymptomatic patent ductus arteriosus in preterm infants

BACKGROUND

Patent Ductus Arteriosus (PDA remains a significant cause of mortality and morbidity in premature infants. Indomethacin is an effective treatment to close a PDA, and has been used for many years with several treatment regimes, including prophylactic use in all at risk premature infants. There are however concerns regarding adverse side effects of indomethacin. By targeting a group of infants with an asymptomatic PDA, rather than treating all VLBW infants prophylactically, indomethacin use would be restricted, limiting the possibility of significant side effects to those with greater chance of benefit.

OBJECTIVES

To assess whether in premature neonates with asymptomatic PDA, treatment with indomethacin improves short and long term outcomes; in particular: incidence of symptomatic PDA, mortality, chronic neonatal lung disease (CLD), intraventricular haemorrhage (IVH), retinopathy of prematurity (ROP), neurodevelopmental outcome, length of ventilation.

SEARCH STRATEGY

Standard strategies of the Cochrane Neonatal Review Group were used. Searches were made of the Oxford Database of Perinatal Trials, MEDLINE and EMBASE from 1966 to September 2002, CINAHL from 1982 to September 2002, and the Cochrane Controlled Trials Register (CENTRAL/CCTR) in The Cochrane Library, Issue 3, 2002. Searches were also made of previous reviews including cross-referencing, abstracts, and conference and symposia proceedings published in Pediatric Research.

SELECTION CRITERIA

All randomised controlled trials of indomethacin compared with placebo or no intervention for the treatment of asymptomatic PDA in premature infants were eligible.

DATA COLLECTION AND ANALYSIS

Standard methods of the Cochrane Neonatal Review Group were used. Trials identified by the search strategy were independently reviewed by each author and assessed for eligibility and trial quality. Data were then extracted independently by each author and compared, with any differences resolved following discussion. Any additional information required was requested from trial authors. Only published data was available for review. Results are expressed as typical relative risk and typical risk difference for dichotomous outcomes, and weighted mean difference for continuous variables.

MAIN RESULTS

Three small trials involving a total of 97 infants were included. Meta analysis of combined data was possible for seven outcomes. Treatment of an asymptomatic PDA with indomethacin significantly reduced the incidence of symptomatic PDA (RR 0.36, 95% CI 0.19, 0.68) and duration of supplemental oxygen (WMD -12.5, 95% CI -23.8, -1.26). There was no evidence of effect on mortality (RR 1.32, 95% CI 0.45, 3.86), CLD (RR 0.91, 95% CI 0.62, 1.35), IVH (RR 1.21, 95% CI 0.62, 2.37), ROP (RR 0.68, 95% CI 0.26, 1.78), or length of ventilation (WMD -7.00 days, 95%CI -17.33, 3.34). Long term neurodevelopmental outcomes were not reported. One trial reported a significant reduction in the duration of supplemental oxygen following treatment with indomethacin in the subgroup of infants with birth weight less than 1000g.

REVIEWER'S CONCLUSIONS

This review demonstrates a significant decrease in the incidence of symptomatic PDA following treatment of an asymptomatic PDA with indomethacin. There is also a small but statistically significant decrease in the duration of requirement for supplemental oxygen. There are no reported long term outcomes in the included trials, and so it is not possible to comment on possible long term effects. Further studies are required to determine the long term benefits or harms of closing a PDA prior to the onset of symptoms.