Cyclosporin A Administration during Pregnancy Induces a Permanent Nephron Deficit in Young Rabbits

Three-dimensional morphometry of kidney in New Zealand rabbit using unbiased design-based stereology

The rabbit is widely used as a laboratory animal in experimental models of kidney diseases. This species is also important from a veterinary perspective as a companion animal. Stereology has been accepted as an accurate approach to kidney morphometry. The objective of the present project was to provide normal quantitative stereological parameters for adult rabbit kidneys. The left kidneys of five adult male New Zealand rabbits were used. Isotropic sections were obtained using the orientation method. Total kidney volume was calculated by the Cavalieri principle. The volume fraction of the renal structures was estimated using the point counting system. The lengths of the proximal convoluted tubule (PCT) and distal convoluted tubule (DCT) were calculated using counting frames. The total glomerular number was accounted for using the physical/fractionator technique. The mean glomerular volume was obtained by dividing the total volume of glomeruli by their total number. The total volume of rabbit kidneys calculated was 10.39 ± 1.98 cm3. The fractional volume of the kidney cortex and medulla accounted for 57.79 ± 0.65% and 42.2 ± 0.65%, respectively. The total glomerular volume was 2.18 ± 0.32% of the whole kidney. The total number of glomeruli in the rabbit kidney was estimated as 204.68 ± 12 × 103. The mean glomerular volume measured 1.07 ± 0.12 × 106 μm3. The total length of PCT and DCT was 2.96 ± 0.29 km and 1.38 ± 0.24 km, respectively. These findings can be used as a reference in experimental nephrology research and may help to expand the knowledge of nephrology in mammals by comparing with available data on humans and other species. RESEARCH HIGHLIGHTS: Three-dimensional morphometry of adult rabbit kidney structures was analyzed using quantitative stereology. Total volume of kidney, fractional volume of cortex and medulla, length of renal tubules and number of nephrons were estimated. These three-dimensional morphometrical data can be used as a reference in experimental nephrology research and may help to expand the knowledge of nephrology in mammals.

Translational insights into mechanisms and preventive strategies after renal injury in neonates

Adverse perinatal circumstances can cause acute kidney injury (AKI) and contribute to chronic kidney disease (CKD). Accumulating evidence indicate that a wide spectrum of perinatal conditions interferes with normal kidney development and ultimately leads to aberrant kidney structure and function later in life. The present review addresses the lack of mechanistic knowledge with regard to perinatal origins of CKD and provides a comprehensive overview of pre- and peri-natal insults, including genetic predisposition, suboptimal nutritional supply, obesity and maternal metabolic disorders as well as placental insufficiency leading to intrauterine growth restriction (IUGR), prematurity, infections, inflammatory processes, and the need for life-saving treatments (e.g. oxygen supplementation, mechanical ventilation, medications) in neonates. Finally, we discuss future preventive, therapeutic, and regenerative directions. In summary, this review highlights the perinatal vulnerability of the kidney and the early origins of increased susceptibility toward AKI and CKD during postnatal life. Promotion of kidney health and prevention of disease require the understanding of perinatal injury in order to optimize perinatal micro- and macro-environments and enable normal kidney development.

Comparison of pregnancy outcomes in Dutch kidney recipients with and without calcineurin inhibitor exposure: a retrospective study

Within pregnancies occurring between 1986 and 2017 in Dutch kidney transplant recipients (KTR), we retrospectively compared short‐term maternal and foetal outcomes between patients on calcineurin inhibitor (CNI) based (CNI+) and CNI‐free immunosuppression (CNI−). We identified 129 CNI+ and 125 CNI− pregnancies in 177 KTR. Demographics differed with CNI+ having higher body mass index (P = 0.045), shorter transplant‐pregnancy interval (P < 0.01), later year of transplantation and ‐pregnancy (P < 0.01). Serum creatinine levels were numerically higher in CNI+ in all study phases, but only reached statistical significance in third trimester (127 vs. 105 µm; P < 0.01), where the percentual changes from preconceptional level also differed (+3.1% vs. −2.2% in CNI−; P = 0.05). Postpartum both groups showed 11–12% serum creatinine rise from preconceptional level. Incidence of low birth weight (LBW) tended to be higher in CNI+ (52% vs. 46%; P = 0.07). Both groups showed equal high rates of preterm delivery. Using CNIs during pregnancy lead to a rise in creatinine in the third trimester but does not negatively influence the course of graft function in the first year postpartum or direct foetal outcomes. High rates of preterm delivery and LBW in KTR, irrespective of CNI use, classify all pregnancies as high risk.

Selected Biochemical Parameters in Children of Mothers After Kidney Transplantation

INTRODUCTION

The number of pregnant kidney graft recipients receiving immunosuppressive drugs is increasing yearly. All potentially nephrotoxic and hepatotoxic immunosuppressive drugs penetrate through the placenta, which raises questions about their long-term effects on offspring.

OBJECTIVES

The study aimed to evaluate the influence of immunosuppressive drugs used by pregnant women after kidney transplantation on the biochemical parameters of their children.

MATERIALS AND METHODS

Forty children born to mothers after kidney transplantation (KTx) and 40 children of healthy mothers from the control group were included in the study. All graft-recipient mothers received immunosuppressive treatment during pregnancy. The study compared biochemical parameters, including urea, creatinine, potassium, and sodium, in both groups.

RESULTS

Elevated creatinine level was observed in 1 newborn in the KTx group and none of the children from the control group (P = .500). All KTx children had normal urea levels, while in the control group, 2 newborns had an increased level of urea (P = .247). Elevated potassium levels were observed in 10% of children in the KTx group and 20% of children in the control group (χ² = 0.881; P = .348). Elevated sodium levels were observed in 22.5% of children in the KTx group and 32.5% of children in the control group (χ² = 1.001; P =.317). No child in the KTx group had hyponatremia; mild hyponatremia was observed in 5% of children in the control group (P = .247).

CONCLUSION

There was no increased risk of an abnormal concentration of urea, creatinine, sodium, and potassium in the offspring of mothers after kidney transplantation using immunosuppressive drugs during pregnancy.

Specific dermatoses of pregnancy other than pemphigoid gestationis

Specific dermatoses of pregnancy are skin disorders that occur specifically during or immediately after pregnancy and cannot be found in non-pregnant patients. According to the current consensus, they include atopic eruption of pregnancy (AEP), polymorphic eruption of pregnancy (PEP), pemphigoid gestationis (PG), and intrahepatic cholestasis of pregnancy (ICP). The diagnosis of specific dermatoses of pregnancy can be challenging due to their variation in clinical presentation; moreover, the tests currently available do not always provide the clue for the diagnosis. However, some distinctive features may be helpful to differentiate between such entities. Accordingly, the knowledge of specific dermatoses of pregnancy and of their management is critical, since their early recognition may allow to provide care for the mother and prevent potential increased fetal risk. In fact, while AEP and PEP do not affect maternal and fetal prognosis, PG and, mainly, ICP are associated to maternal complications as well as the risk of fetal loss. In this paper, the epidemiology, pathogenesis, clinical features as well as management of AEP and PEP are reviewed in detail, while PG is described in another article of this issue. Moreover, the main features of ICP, which cannot be considered a primarily skin disease but may be managed first by dermatologists, are reported.

Effects of Cyclosporine A on the Development of Metanephros in the Pregnant BALB/c Mice

Background:

Cyclosporine A (CsA) is a commonly used clinical immunosuppressant. However, CsA exposure in rabbits during the gestation period was shown to cause a postnatal decrease in the number of nephrons, with the effects remaining unknown. In this study, we aimed to explore the effects of CsA on metanephros development in the pregnant BALB/c mice.

Methods:

Pregnant mice were randomly divided into two groups, and CsA (10 mg·kg⁻¹·d⁻¹) was subcutaneously injected from gestation day 10.5 to day 16.5 in the CsA group, whereas a comparable volume of normal saline was given to the control group. All of the mice were sacrificed on gestation day 17.5 and serum CsA concentration was measured. The fetuses were removed and weighed, and their kidneys were prepared for histological assessment and polymerase chain reaction assay. In an in vitro experiment, embryo kidneys of fetal mice on gestation day 12.5 were used, and CsA (10 μmol/L) was added in the culture of the CsA group. The growth pattern of the ureteric bud and nephrons was assessed by lectin staining.

Results:

No significant differences in the weight of embryo (4.54 ± 1.22 vs. 3.26 ± 1.09 mg) were observed between the CsA and control groups, the thickness of the cortical (510.0 ± 30.3 vs. 350.0 ± 29.7 μm, P < 0.05) and nephrogenic zone (272.5 ± 17.2 vs. 173.3 ± 24.0 μm, P < 0.05), and the number of glomeruli (36.5 ± 0.7 vs. 27.5 ± 2.1, P < 0.05) were reduced in the CsA group when compared to the control group. The cell proliferation of Ki-67 positive index between control and CsA group (307.0 ± 20.0 vs. 219.0 ± 25.0, P < 0.05) in the nephrogenic zone was decreased with the increase of apoptotic cells (17.0 ± 2.0 vs. 159.0 ± 33.0, P < 0.05). The mRNA expression of WT-1, Pax2, and Pax8 was downregulated by CsA treatment. As for the in vitro CsA group, the branch number of the ureteric bud was decreased in the CsA-treated group with the nephrons missing in contrast to control after the incubation for 24 h and 72 h (all P < 0.0001).

Conclusion:

Treatment of CsA suppressed metanephros development in the pregnant mice; however, the potential action of mechanism needs to be further investigated.

Nephron number and its determinants in early life: a primer

Although there is wide variation, humans possess on average 900,000 nephrons per kidney. So far as is known, nephrons cannot regenerate; therefore, an individual's nephron endowment has profound implications in determining his or her long-term risk of developing chronic kidney disease. Most of the variability in human nephron number is determined early in life. Nephrogenesis is a complex and carefully orchestrated process that occurs during a narrow time window until 36 weeks gestation in humans, and disruption of any part of this sequence may lead to reduced nephron number. In utero, genetic abnormalities, toxic insults, and nutritional deficiencies can each alter final nephron number. Infants born prematurely must continue nephrogenesis in an ex utero environment where there may be multiple threats to successful nephrogenesis. Once the nephron endowment is determined, postnatal factors (such as acute kidney injury or chronic illnesses) can only decrease nephron number. Current techniques for estimating nephron number require an invasive procedure or complete destruction of the tissue, making noninvasive means for counting nephron surgently needed. A better understanding of nephron number and its determinants, particularly during growth and maturation, could allow the development of therapies to support, prolong, or resume nephrogenesis.

Renal teratogens

In utero exposure to certain drugs early in pregnancy may adversely affect nephrogenesis. Exposure to drugs later in pregnancy may affect the renin-angiotensin system, which could have an impact on fetal or neonatal renal function. Reduction in nephron number and renal function could have adverse consequences for the child several years later. Data are limited on the information needed to guide decisions for patients and providers regarding the use of certain drugs in pregnancy. The study of drug nephroteratogenicity has not been systematized, a large, standardized, global approach is needed to evaluate the renal risks of in utero drug exposures.

Proximal nephron

The kidney plays a fundamental role in maintaining body salt and fluid balance and blood pressure homeostasis through the actions of its proximal and distal tubular segments of nephrons. However, proximal tubules are well recognized to exert a more prominent role than distal counterparts. Proximal tubules are responsible for reabsorbing approximately 65% of filtered load and most, if not all, of filtered amino acids, glucose, solutes, and low molecular weight proteins. Proximal tubules also play a key role in regulating acid-base balance by reabsorbing approximately 80% of filtered bicarbonate. The purpose of this review article is to provide a comprehensive overview of new insights and perspectives into current understanding of proximal tubules of nephrons, with an emphasis on the ultrastructure, molecular biology, cellular and integrative physiology, and the underlying signaling transduction mechanisms. The review is divided into three closely related sections. The first section focuses on the classification of nephrons and recent perspectives on the potential role of nephron numbers in human health and diseases. The second section reviews recent research on the structural and biochemical basis of proximal tubular function. The final section provides a comprehensive overview of new insights and perspectives in the physiological regulation of proximal tubular transport by vasoactive hormones. In the latter section, attention is particularly paid to new insights and perspectives learnt from recent cloning of transporters, development of transgenic animals with knockout or knockin of a particular gene of interest, and mapping of signaling pathways using microarrays and/or physiological proteomic approaches.

Pregnancy management of diabetic renal transplant patients

Advances in medical care and options for medications for diabetic kidney transplant recipients have allowed for successful pregnancies to be carried to full term. End-stage renal disease leads to impaired fertility. Fertility is restored 1 to 6 months after a successful kidney transplant. Poor glycemic control near the conception period leads to a higher incidence of major fetal malformations and spontaneous abortion. Preconception counseling about risks of medications, control of comorbid conditions, stability of allograft function, and potential risks to mother, fetus, and allograft has to be done. Close and careful monitoring of mother, fetus, and allograft is important in ensuring a good outcome.

Double filtration plasmapheresis in different diseases in Thailand

Double filtration plasmapheresis (DFPP) was applied to the treatment of two different categories from 100 cases that had been collected over a 5 year period (2007-2011). These categories were allocated into groups by size of toxic substances, which were classified as two different kinds of diseases. Group I comprised diseases that were caused by alloimmunity in transplantation, autoimmune diseases, complicated nephrotic syndrome, pure red cell aplasia, and toxemia of pregnancy. This group was treated with a plasma separator (plasmaflow-05, Asahi Kasei) and plasma fractionators, EC-20W. The second group, which included hyperviscosity syndrome, was treated by the same plasma separator, but with different plasma fractionators using EC-40W. This group included diabetes nephropathy, hyperlipidemia, peripheral arterial diseases, and neurosensory hearing loss. Both groups used 1.5 plasma volumes in each treatment for three sessions in two consecutive weeks. The result of treatment in group I showed that plasma immunoglobulin G (IgG) was decreased substantially by 66% in either transplant or lupus nephritis patients after the third session. In the second group, IgM, fibrinogen, and lipid markedly responded to the treatment. Two diabetes nephropathy patients showed stable renal function for more than 12 months. Peripheral arterial disease was shown to benefit from significantly decreasing fibrinogen and IgM, which resulted in clinical tissue oxygenation. Neither bleeding diathesis nor membrane anaphylaxis were reported from the treatment. In summary, apheresis patients were shown to benefit in hypersensitized and hyperviscosity syndrome.

Calcineurin inhibitors and immunosuppression - a tale of two isoforms

Organ transplantation is the state of the art for treating end-stage organ failure. Over 25000 organ transplants are performed in the USA each year. Survival rates following transplantation are now approaching 90% for 1 year and 75% for 5 years. Central to this success was the introduction of drugs that suppress the immune system and prevent rejection. The most commonly used class of immunosuppressing drugs are calcineurin inhibitors (CNIs). Calcineurin is a ubiquitous enzyme that is important for T-cell function. With more people taking CNIs for longer and longer periods of time the consequences of calcineurin inhibition on other organ systems - particularly the kidney - have become a growing concern. Virtually all people who take a CNI will develop some degree of kidney toxicity and up to 10% will progress to kidney failure. In the past 15 years, research into calcineurin action has identified distinct actions of the two main isoforms of the catalytic subunit of the enzyme. The α-isoform is required for kidney function whereas the β-isoform has a predominant role in the immune system. This review will discuss the current state of knowledge about calcineurin isoforms and how these new insights may reshape post-transplant immunosuppression.

Atopic dermatitis in pregnancy: current status and challenges

Atopic dermatitis (AD) is the most common pregnancy dermatosis. This evidence-based review article provides an evaluation of AD in gestation. Our literature search revealed 4 epidemiologic studies on AD in pregnancy, and a total of 55 articles that provide the basis for this review. The limitations of epidemiologic studies included herein are critically reviewed. The management of AD in gestation is reviewed with an emphasis on drug safety. Further studies are required to determine whether it is the intrinsic ("nonallergic" or "atopiform dermatitis") and/or extrinsic (IgE-associated) AD that is affected by pregnancy, and to establish the postpartum prognosis of "new atopic dermatitis" (AD presenting for the first time in pregnancy). A revision of the diagnostic criteria will allow a more accurate confirmation of the prevalence of AD, and especially "new atopic dermatitis," in pregnancy as well as differentiation of AD from specific dermatoses of pregnancy, such as prurigo and pruritic folliculitis. Addressing the above issues and unraveling the etiopathogenesis of AD in pregnancy will help clarify a suggested overlap with the above specific dermatoses.

Molecular Diagnostics of Calcineurin-Related Pathologies

BACKGROUND

The Ca2+-dependent protein phosphatase enzyme calcineurin (Cn) (protein phosphatase 3) is best known for its role as director of the adaptive immune response. One of its principal substrates is the nuclear factor of activated T cells (NFAT), which translocates to the nucleus after dephosphorylation to mediate gene transcription. Drugs targeting Cn (the Cn inhibitors tacrolimus and cyclosporin A) have revolutionized posttransplantation therapy in allograft recipients by considerably reducing rejection rates.

CONTENT

Owing primarily to intensive study of the side effects of the Cn inhibitors, the unique importance of Cn and Cn/NFAT signaling in the normal physiological processes of many other cell and tissue types is becoming more evident. During the last decade, it has become clear that an extensive and diverse array of clinical conditions can be traced back, at least in part, to a disturbed Cn-signaling axis. Hence, both diagnostics and therapeutic monitoring could benefit from a technique that conveniently reads out Cn/NFAT operative status.

SUMMARY

This review outlines the current knowledge on the pathologic conditions that have calcineurin as a common denominator and reports on the progress that has been made toward successfully applying Cn and Cn/NFAT activity markers in molecular diagnostics.

Use of cyclosporine in uterine transplantation

Uterine transplantation has been proposed as a possible solution to absolute uterine factor infertility untreatable by any other option. Since the first human attempt in 2000, various teams have tried to clarify which immunosuppressant would be most suitable for protecting the allogeneic uterine graft while posing a minimal risk to the fetus. Cyclosporine A (CsA) is an immunosuppressant widely used by transplant recipients. It is currently being tested as a potential immunosuppressant to be used during UTn. Its effect on the mother and fetus and its influence upon the graft during pregnancy have been of major concern. We review the role of CsA in UTn and its effect on pregnant transplant recipients and their offspring.

Control of kidney development by calcium ions

From the formation of a simple kidney in amphibian larvae, the pronephros, to the formation of the more complex mammalian kidney, the metanephros, calcium is present through numerous steps of tubulogenesis and nephron induction. Several calcium-binding proteins such as regucalcin/SMP-30 and calbindin-D28k are commonly used to label pronephric tubules and metanephric ureteral epithelium, respectively. However, the involvement of calcium and calcium signalling at various stages of renal organogenesis was not clearly delineated. In recent years, several studies have pinpointed an unsuspected role of calcium in determination of the pronephric territory and for conversion of metanephric mesenchyme into nephrons. Influx of calcium and calcium transients have been recorded in the pool of renal progenitors to allow tubule formation, highlighting the occurrence of calcium-dependent signalling events during early kidney development. Characterization of nuclear calcium signalling is emerging. Implication of the non-canonical calcium/NFAT Wnt signalling pathway as an essential mechanism to promote nephrogenesis has recently been demonstrated. This review examines the current knowledge of the impact of calcium ions during embryonic development of the kidney. It focuses on Ca(2+) binding proteins and Ca(2+) sensors that are involved in renal organogenesis and briefly examines the link between calcium-dependent signals and polycystins.

Calcium/NFAT signalling promotes early nephrogenesis

A number of Wnt genes are expressed during, and are known to be essential for, early kidney development. It is typically assumed that their products will act through the canonical β-catenin signalling pathway. We have found evidence that suggests canonical Wnt signalling is not active in the early nephrogenic metanephric mesenchyme, but instead provide expressional and functional evidence that implicates the non-canonical Calcium/NFAT Wnt signalling pathway in nephrogenesis. Members of the NFAT (Nuclear Factor Activated in T cells) transcription factor gene family are expressed throughout murine kidney morphogenesis and NFATc3 is localised to the developing nephrons. Treatment of kidney rudiments with Cyclosporin A (CSA), an inhibitor of Calcium/NFAT signalling, decreases nephron formation — a phenotype similar to that in Wnt4^−/− embryos. Treatment of Wnt4^−/− kidneys with Ionomycin, an activator of the pathway, partially rescues the phenotype. We propose that the non-canonical Calcium/NFAT Wnt signalling pathway plays an important role in early mammalian renal development and is required for complete MET during nephrogenesis, potentially acting downstream of Wnt4.

Effect of drugs on renal development

Many 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.

Cyclosporine A exposure during pregnancy in mice: effects on reproductive performance in mothers and offspring

BACKGROUND

Pregnancies after organ transplantation and under immunosuppressive treatment are associated with slightly elevated risks for obstetric and post-natal complications but can usually be managed well. However, little is known about the effects of intrauterine exposure (IUE) to immunosuppressants in the growing and adult offspring. One major issue is the potentially negative effects of immunosuppressive medication on reproduction. This study investigates the effect of exposure during pregnancy to the most commonly used immunosuppressant in organ transplantation, cyclosporine A (CsA), on the reproductive outcome in mothers and offspring.

METHODS

Female C57CBA-F1 mice received 0, 10, 20 or 30 mg/kg bodyweight of CsA daily by subcutaneous mini-osmotic pumps during mating and pregnancy. Blood concentrations of CsA, implantation rates, resorption rates and fetal weights were analysed. In addition, female and male mice exposed to CsA in utero were mated to unexposed partners and pregnancy outcomes were analysed.

RESULTS

Direct maternal exposure to CsA at high doses reduced implantation rates and fetal survival. IUE to CsA reduced adolescent growth but did not affect fertility, although a reduction in birthweight was seen in offspring of females exposed to CsA in utero.

CONCLUSIONS

CsA exposure during pregnancy correlates with impaired reproductive outcome, but offspring fertility is not affected. The cause of reduction in adolescent weight gain and low birthweight in offspring of females exposed to CsA in utero need further investigation.

Calcineurin a-binding protein, a novel modulator of the calcineurin-nuclear factor of activated T-cell signaling pathway, is overexpressed in wilms' tumors and promotes cell migration

Current therapeutic strategies against Wilms' tumor (WT) reach 80% to 85% success rate. In spite of this, a remaining 15% to 20% of tumors relapse and are associated with increased metastasis and poor prognosis. To identify new regulators of WT progression, we screened for developmental target genes of Pax2, a key regulator of kidney development and a WT signature gene. We show that one of these target genes, calcineurin A-binding protein (CnABP), is coexpressed with Pax2 during kidney development and is overexpressed in >70% of WT samples analyzed. The CnABP gene encodes a novel protein product conserved in higher vertebrates. We show that CnABP promotes cell proliferation and migration in cell culture experiments. Biochemical analyses additionally identified an interaction between CnABP and calcineurin Abeta, the catalytic subunit of the calcium-responsive serine/threonine phosphatase calcineurin. We show that this interaction leads to the inhibition of calcineurin phosphatase activity and prevents nuclear factor of activated T-cell (NFAT) nuclear translocation. Inhibition of NFAT nuclear localization results in decreased NFAT transcriptional response. Together, these data identify a new modulator of calcineurin signaling up-regulated in WTs.

Developmental regulation of calcineurin isoforms in the rodent kidney: association with COX-2

Calcineurin (Cn)-Aα-deficient mice develop abnormalities of postnatal kidney development, similar to that of cyclooxygenase (COX)-2-deficient mice. The present study was undertaken to examine expression and regulation of Cn isoforms in the developing kidney during the postnatal period and further characterize the relationship between Cn and COX-2. The protein expressions of all three Cn isoforms, including Cn-Aα, -Aβ, and -B, as determined by immunoblotting, increased in parallel in the first postnatal week and declined gradually with age. Renal Cn-Aα and -Aβ mRNA expressions were both developmentally regulated in the same fashion as their protein expressions, whereas renal Cn-B1 mRNA was not obviously induced in the first postnatal week. Immunohistochemistry demonstrated colocalization of Cn-Aα, Cn-Aβ, and COX-2 in the same cells of thick ascending limb and macula densa. Administration with cyclosporine A (2.5 mg·kg−1·day−1) during the postnatal period remarkably suppressed renal COX-2 expression as assessed by both immunoblotting and immunohistochemistry. Deletion of Cn-Aα but not Cn-Aβ in mice significantly reduced renal COX-2 expression at the postnatal period. Together, these data suggest that renal Cn isoforms are subject to normal developmental regulation and they may play a role in postnatal kidney development via interaction with COX-2.

Ectopic expression of the homeobox gene Cux-1 rescues calcineurin inhibition in mouse embryonic kidney cultures

Cux-1 is a murine homeobox gene structurally related to Drosophila cut. Cux-1 is highly expressed in the nephrogenic zone of the developing kidney, where its expression coincides with cell proliferation. Cux-1 functions as a transcriptional repressor of the cyclin kinase inhibitors (CKI) p21 and p27. Cux-1 DNA binding activity is negatively regulated by phosphorylation, and dephosphorylation of Cux-1 results in increased DNA binding. Transgenic mice ectopically expressing Cux-1 develop renal hyperplasia associated with the down-regulation of the CKI p27. Calcineurin A (CnA) alpha (-/-) mice display renal hypoplasia associated with the ectopic expression of p27. CnA is a serine/threonine phosphatase activated by intracellular calcium. Inhibiting CnA with cyclosporin A (CsA) leads to nephron deficit in rat metanephric organ cultures and apoptosis in various renal cell lines. To determine whether the ectopic expression of p27 in CnA-alpha -/- kidneys results from the down-regulation of Cux-1, metanephroi from embryonic Cux-1 transgenic and wild-type mice were harvested and cultured with CsA for 5 days. CsA treatment significantly inhibited growth of wild-type metanephroi. In contrast, CsA-treated Cux-1 transgenic kidney cultures were not growth inhibited, but showed high levels of cell proliferation in the nephrogenic zone. Moreover, in CsA-treated Cux-1 transgenic kidney cultures, p27 was not expressed in the nephrogenic zone, but only up-regulated in maturing glomeruli and tubules. Taken together, our results demonstrate that ectopic expression of Cux-1 can rescue the effects of CsA inhibition of CnA and suggest that Cux-1 may be regulated by calcineurin A.

Cyclosporin-A augments respiratory burst of whole blood phagocytes in pregnant rats

Both pregnancy and cyclosporin A (CsA) are known to inhibit T-cell mediated immune response and to activate phagocytes against microbial infections as a compensatory mechanism. Pregnant women, either with organ transplantation or suffering from autoimmune diseases, are commonly managed with CsA therapy. This investigation was aimed to study effect of CsA on phagocytic activity of whole blood polymorphonuclear leukocytes (PMNs) in pregnant rats. Both pregnant and non-pregnant Sprague-Dawley rats (4 animals per group) were treated with CsA (40 mg/kg, oral) for 7 days starting from gestation day 7. Respective control groups of non-pregnant and pregnant rats received vehicle only. Luminol-dependent chemiluminescence (CL) was used to measure the generation of reactive oxygen species (ROS) in respiratory burst of whole blood PMNs stimulated by zymosan. The results showed a moderate and insignificant increase in CL response in non-pregnant rats with CsA treatment or pregnant rats without CsA treatment. Whereas the CL response of whole blood PMNs was significantly higher (ANOVA F = 35.66, P < 0.001) in pregnant rats treated with CsA. In conclusion, this preliminary study demonstrates synergistic effects of pregnancy and CsA on activation of PMNs resulting in massive and sustained generation of ROS that could be deleterious to both host and fetus.

Effects of maternally administered drugs on the fetal and neonatal kidney

The number of pregnant women and women of childbearing age who are receiving drugs is increasing. A variety of drugs are prescribed for either complications of pregnancy or maternal diseases that existed prior to the pregnancy. Such drugs cross the placental barrier, enter the fetal circulation and potentially alter fetal development, particularly the development of the kidneys. Increased incidences of intrauterine growth retardation and adverse renal effects have been reported. The fetus and the newborn infant may thus experience renal failure, varying from transient oligohydramnios to severe neonatal renal insufficiency leading to death. Such adverse effects may particularly occur when fetuses are exposed to NSAIDs, ACE inhibitors and specific angiotensin II receptor type 1 antagonists. In addition to functional adverse effects, in utero exposure to drugs may affect renal structure itself and produce renal congenital abnormalities, including cystic dysplasia, tubular dysgenesis, ischaemic damage and a reduced nephron number. Experimental studies raise the question of potential long-term adverse effects, including renal dysfunction and arterial hypertension in adulthood. Although neonatal data for many drugs are reassuring, such findings stress the importance of long-term follow-up of infants exposed in utero to certain drugs that have been administered to the mother.

Protective Role of Polyphenols in Cyclosporine A-induced Nephrotoxicity During Rat Pregnancy

The aim of this study was to evaluate the adverse effects of cyclosporine A (CsA) toward renal morphogenesis and to test the renoprotective natural antioxidants such as provinol (PV). Pregnant rats were divided into four groups. Group I was injected SC with olive oil. Group II was treated with oral administration of PV and was used as control. Group III animals were injected SC daily with CsA, and group IV animals were injected daily with CsA and PV for 21 days of pregnancy. Five pups per litter were killed and the kidneys removed and treated by morphological and immunohistochemical (IHC) methods. IHC analysis considered two proteins responsible for nephrotoxicity in adult rats: inducible nitric oxide (iNOS) and matrix metalloproteinase-2 (MMP2). Pregnancy outcomes among CsA-treated rats demonstrated a reduced number of pups. Pups that were exposed antenatally to CsA presented several pathologic findings in all immature parenchyma and an increase in iNOS and MMP2 expression. These side effects were not observed in kidney of litters born from CsA + PV-treated mothers. Our study indicates that CsA induces morphological alterations in renal parenchyma of neonates and that PV plays a protective role against these side effects.

An emerging role for calcineurin Aalpha in the development and function of the kidney

For many years, calcineurin has been a familiar molecule as a target of the immunosuppressive agents cyclosporin A and FK-506. Calcineurin inhibition interferes with T cell signaling by preventing activation of the transcription factor NFATc. However, calcineurin is expressed in most tissues in the body, and calcineurin inhibition undoubtedly alters many other cellular processes. As a result, serious side effects of calcineurin inhibitors regularly occur, including hypertension and renal dysfunction. Because nephrotoxicity is often a barrier to continued clinical use of calcineurin inhibitors, understanding the role of calcineurin in the kidney is of particular importance. Recent work has demonstrated that the two main isoforms of the catalytic subunit of calcineurin, Aalpha and Abeta, may have distinct functions, particularly in the kidney. Calcineurin isoforms may be differentially expressed, and/or the activity of each may be differentially regulated, leading to tissue-specific functions. Differences between the action of the two isoforms are most evident in knockout mice lacking each isoform. Mice lacking the beta-isoform are characterized principally by altered development and function of immune cells. alpha-Knockout mice, in contrast, can still be immune suppressed by cyclosporin A but display pervasive developmental defects, including renal dysfunction. Therefore, it is intriguing to consider that while the beta-isoform may be responsible for calcineurin action in T cells, the alpha-isoform may be the predominant catalytic isoform in the kidney. This conclusion, if correct, may have substantial clinical implication for novel strategies to selectively target calcineurin action in T cells without associated nephrotoxicity.

Myasthenia gravis: management issues during pregnancy

Myasthenia gravis (MG) often affects women in the second and third decades of life, overlapping with the childbearing years. The course of the disease is unpredictable during pregnancy; however, worsening of symptoms occurs more likely during the first trimester and postpartum. MG can be well managed during pregnancy with relatively safe and effective therapies. Anticholinesterase drugs are the mainstay of treatment, when MG symptoms are not satisfactorily controlled, corticosteroids, azathioprine and in some cases cyclosporin A can be used. Until information is available regarding safety, mycophenolate mofetil should be discontinued before pregnancy. Pregnancy should be avoided in women treated with methotrexate because of the risk of causing typical malformations. Plasmapheresis and intravenous immunoglobulins have been successfully used in the treatment of MG crisis during pregnancy. Caesarean section is recommended only for obstetric reasons; forceps delivery and vacuum extraction are sometimes required. Epidural anesthesia is advised to reduce physical and emotional stress. MG during pregnancy can lead to serious life-threatening conditions, including respiratory insufficiency; therefore, intensive checkups by a gynaecologist and a neurologist are necessary. Women with myasthenia gravis should not be discouraged from conceiving; however, they should discuss their plan for pregnancy with their neurologist and their gynaecologist.

Activation of Gαq-Coupled Signaling Pathways in Glomerular Podocytes Promotes Renal Injury

The glomerular podocyte plays a key role in maintaining the integrity of the glomerular filtration barrier. This function may be regulated by activation of cell surface G protein-coupled receptors (GPCR). Studies suggest that podocytes express GPCR that are implicated in the pathogenesis of glomerular diseases. Common to these GPCR systems is activation of phospholipase C through the Gq alpha-subunit (Galpha q). For investigating the role of Galpha q-coupled signaling pathways in promoting renal injury in podocytes, a constitutively active Galpha q subunit (Galpha qQ > L) was expressed in glomerular podocytes using the mouse nephrin promoter. Transgenic (TG) mice demonstrated albuminuria as well as a decrease in both kidney mass and nephron number. By light microscopy, a portion of the TG mice had glomerular abnormalities, including focal to diffuse hypercellularity and segmental sclerosis. Consistent with injury-promoting effects of Galpha qQ > L, there was a significant reduction in podocalyxin mRNA as well as nephrin mRNA and protein levels in glomeruli from TG mice compared with non-TG controls. Expression of the transgene also seemed to increase susceptibility to glomerular injury, because treatment with puromycin aminonucleoside enhanced proteinuria in TG mice compared with non-TG littermate controls (4.2 +/- 1.0 [TG] versus 1.6 +/- 0.3 [non-TG] mg/24 h; P = 0.0161). Thus, activation of Galpha q in glomerular podocytes caused alterations in glomerular histomorphology, albuminuria, decreased nephron mass, and reduced glomerular expression of both nephrin and podocalyxin as well as enhanced susceptibility to glomerular damage induced by puromycin aminonucleoside. It is speculated that Galpha q-coupled signaling cascades may be important effector pathways mediating renal injury.

Calcineurin A-alpha but not A-beta is required for normal kidney development and function

Calcineurin is an important signaling molecule in the kidney and may be involved in a variety of processes. The phosphatase subunit of calcineurin (CnA) has three isoforms, alpha, beta, and gamma. In this study, we investigated the effect of loss of calcineurin A-alpha (CnA-alpha) or calcineurin A-beta (CnA-beta) on the development and function of the kidney. Total calcineurin expression and activity was significantly reduced in whole kidney homogenates from both CnA-alpha -/- and CnA-beta -/- mice. Kidneys of CnA-beta -/- mice appear normal and the mice develop with no phenotypic abnormalities. In contrast, kidneys of CnA-alpha -/- animals fail to fully develop. In particular, postnatal maturation of the nephrogenic zone (NZ) is defective. Within the NZ, glomeruli also fail to mature and lack mesangial cells. In addition to alterations in development, there is an absence of proliferation and an increase of cell death in the NZ with loss of CnA-alpha. Finally, increased collagen deposition is observed and serum creatinine levels are significantly increased in CnA-alpha -/- animals compared to wild-type littermates, indicating that kidney function is impaired. In summary, absence of CnA-alpha but not CnA-beta leads to a defect in normal maturation of the NZ and glomeruli, alterations in the cell cycle, and impaired kidney function.