Forecasting Fetal Buprenorphine Exposure through Maternal-Fetal Physiologically Based Pharmacokinetic Modeling.

Buprenorphine readily crosses the placenta, and with greater prenatal exposure, neonatal opioid withdrawal syndrome (NOWS) likely grows more severe. Current dosing strategies can be further improved by tailoring doses to expected NOWS severity. To allow the conceptualization of fetal buprenorphine exposure, a maternal-fetal physiologically based pharmacokinetic (PBPK) model for sublingual buprenorphine was developed using Simcyp (v21.0). Buprenorphine transplacental passage was predicted from its physicochemical properties. The maternal-fetal PBPK model integrated reduced transmucosal absorption driven by lower salivary pH and induced metabolism observed during pregnancy. Maternal pharmacokinetics was adequately predicted in the second trimester, third trimester, and postpartum period, with the simulated area under the curve from 0 to 12 h, apparent clearance, and peak concentration falling within the 1.25-fold prediction error range. Following post hoc adjustment of the likely degree of individual maternal sublingual absorption, umbilical cord blood concentrations at delivery (n = 21) were adequately predicted, with a geometric mean ratio between predicted and observed fetal concentrations of 1.15 and with 95.2% falling within the 2-fold prediction error range. The maternal-fetal PBPK model developed in this study can be used to forecast fetal buprenorphine exposure and would be valuable to investigate its correlation to NOWS severity.

Physiologically-Based Pharmacokinetic Modeling to Investigate the Effect of Maturation on Buprenorphine Pharmacokinetics in Newborns with Neonatal Opioid Withdrawal Syndrome.

Neonatal opioid withdrawal syndrome (NOWS) is a major public health concern whose incidence has paralleled the opioid epidemic in the United States. Sublingual buprenorphine is an emerging treatment for NOWS, but given concerns about long-term adverse effects of perinatal opioid exposure, precision dosing of buprenorphine is needed. Buprenorphine pharmacokinetics (PK) in newborns, however, is highly variable. To evaluate underlying sources of PK variability, a neonatal physiologically-based pharmacokinetic (PBPK) model of sublingual buprenorphine was developed using Simcyp (version 19.1). The PBPK model included metabolism by cytochrome P450 (CYP) 3A4, CYP2C8, UDP-glucuronosyltransferase (UGT) 1A1, UGT1A3, UGT2B7, and UGT2B17, with additional biliary excretion. Maturation of metabolizing enzymes was incorporated, and default CYP2C8 and UGT2B7 ontogeny profiles were updated according to recent literature. A biliary clearance developmental profile was outlined using clinical data from neonates receiving sublingual buprenorphine as NOWS treatment. Extensive PBPK model validation in adults demonstrated good predictability, with geometric mean (95% confidence interval (CI)) predicted/observed ratios (P/O ratios) of area under the curve from zero to infinity (AUC0-∞ ), peak concentration (Cmax ), and time to reach peak concentration (Tmax ) equaling 1.00 (0.74-1.33), 1.04 (0.84-1.29), and 0.95 (0.72-1.26), respectively. In neonates, the geometric mean (95% CI) P/O ratio of whole blood concentrations was 0.75 (95% CI 0.64-0.87). PBPK modeling and simulation demonstrated that variability in biliary clearance, sublingual absorption, and CYP3A4 abundance are likely important drivers of buprenorphine PK variability in neonates. The PBPK model could be used to guide development of improved buprenorphine starting dose regimens for the treatment of NOWS.

A review of pregnancy-induced changes in opioid pharmacokinetics, placental transfer, and fetal exposure: Towards fetomaternal physiologically-based pharmacokinetic modeling to improve the treatment of neonatal opioid withdrawal syndrome.

Physiologically-based pharmacokinetic (PBPK) modeling has emerged as a useful tool to study pharmacokinetics (PK) in special populations, such as pregnant women, fetuses, and newborns, where practical hurdles severely limit the study of drug behavior. PK in pregnant women is variable and everchanging, differing greatly from that in their nonpregnant female and male counterparts typically enrolled in clinical trials. PBPK models can accommodate pregnancy-induced physiological and metabolic changes, thereby providing mechanistic insights into maternal drug disposition and fetal exposure. Fueled by the soaring opioid epidemic in the United States, opioid use during pregnancy continues to rise, leading to an increased incidence of neonatal opioid withdrawal syndrome (NOWS). The severity of NOWS is influenced by a complex interplay of extrinsic and intrinsic factors, and varies substantially between newborns, but the extent of prenatal opioid exposure is likely the primary driver. Fetomaternal PBPK modeling is an attractive approach to predict in utero opioid exposure. To facilitate the development of fetomaternal PBPK models of opioids, this review provides a detailed overview of pregnancy-induced changes affecting the PK of commonly used opioids during gestation. Moreover, the placental transfer of these opioids is described, along with their disposition in the fetus. Lastly, the implementation of these factors into PBPK models is discussed. Fetomaternal PBPK modeling of opioids is expected to provide improved insights in fetal opioid exposure, which allows for prediction of postnatal NOWS severity, thereby opening the way for precision postnatal treatment of these vulnerable infants.

Utility of Repeat Testing for Congenital Hypothyroidism in Infants with Very Low Birth Weight.

OBJECTIVE: To assess for possible missed hypothyroidism in infants of very low birth weight (VLBW) whose initial newborn screening (NBS) was within normal reference range. STUDY DESIGN: We analyzed serum thyroid-stimulating hormone (TSH) obtained at 36 weeks of corrected gestational age or at hospital discharge if earlier (retest TSH) in infants with VLBW in the neonatal intensive care unit to determine the prevalence and factors associated with retest TSH ≥5 mU/L, a concentration requiring close follow-up for hypothyroidism. Utility of alternative cut-offs for NBS TSH also was assessed. RESULTS: A total of 398 infants, median gestational age 29 (range 22-36) weeks, birth weight 1138 (470-1498) g, were included in this study. Retest TSH was obtained at 49.5 (12-137) days after birth. Median retest TSH was 3.1 (0.5-27.9) mU/L. Seventy-three (18.3%) of the cohort had retest TSH ≥5 mU/L. Adjusting NBS cut-off to ≥15 or ≥10 mU/L identified <50% of infants with TSH ≥5 mU/L, resulting in 6% false positives and >70% false negatives. Multiple regression modeling indicated that 35% of variance in retest TSH value was explained by NBS TSH concentration, birth weight, and gestational age, all P < .01. CONCLUSIONS: Retesting for hypothyroidism at 36 weeks of corrected gestational age in infants with VLBL and normal NBS could identify infants who require ongoing surveillance until thyroid function has been definitively ascertained. Adjusting NBS TSH cutoffs is not a valid option for identifying potential hypothyroidism in infants with VLBW because of lack of sensitivity and unacceptable false-positive and false-negative rates.

Pharmacotherapy of neonatal opioid withdrawal syndrome: a review of pharmacokinetics and pharmacodynamics.

INTRODUCTION: Neonatal opioid withdrawal syndrome (NOWS) often arises in infants born to mothers who used opioids during pregnancy. Morphine, methadone, and buprenorphine are the most common first-line treatments, whereas clonidine and phenobarbital are generally reserved for adjunctive therapy. These drugs exhibit substantial pharmacokinetic (PK) and pharmacodynamic (PD) variability. Current pharmacological treatments for NOWS are based on institutional protocols and largely rely on empirical treatment of patient symptoms. AREAS COVERED: This article reviews the PK/PD of NOWS pharmacotherapies with a focus on the implication of physiological development and maturation. Body size-standardized clearance is consistently low in neonates, except for methadone. This can be ascribed to underdeveloped metabolic and elimination pathways. The effects of pharmacogenetics have been clarified especially for morphine. The PK/PD relationship of medications used in the treatment of NOWS is generally understudied. EXPERT OPINION: Providing an appropriate opioid dose in neonates is challenging. Advancements in quantitative pharmacology and PK/PD modeling approaches facilitate identification of key factors driving PK/PD variability and characterization of exposure-response relationships. PK/PD model-informed simulations have been widely employed to define age-appropriate pediatric dosing regimens. The model-informed approach holds promise to aid more rational use of medications in the treatment of NOWS.

Physiologic Indirect Response Modeling to Describe Buprenorphine Pharmacodynamics in Newborns Treated for Neonatal Opioid Withdrawal Syndrome.

BACKGROUND AND OBJECTIVE: Buprenorphine has been shown to be effective in treating infants with neonatal opioid withdrawal syndrome. However, an evidence-based buprenorphine dosing strategy has not been established in the treatment of neonatal opioid withdrawal syndrome because of a lack of exposure-response data. The aim of this study was to develop an integrated pharmacokinetic and pharmacodynamic model to predict buprenorphine treatment outcomes in newborns with neonatal opioid withdrawal syndrome. METHODS: Clinical data were obtained from 19 newborns with a median (range) gestational age of 37 (34-41) weeks enrolled in a pilot pharmacokinetic study of buprenorphine. Sparse blood sampling, comprising three specimens obtained around the second dose of buprenorphine, was performed using heel sticks with dried blood spot technology. Standardized neonatal opioid withdrawal syndrome severity scores (Finnegan scores) were collected every 3-4 h based on symptoms by bedside nursing staff. Mean Finnegan scores were used as a pharmacodynamic marker in the exposure-response modeling. The blood concentration-Finnegan score relationship was described using a physiologic indirect response model with inclusion of natural disease remission. RESULTS: A total of 52 buprenorphine blood concentrations and 780 mean Finnegan scores were available for the pharmacokinetic/pharmacodynamic modeling and exposure-response analysis. A one-compartment model with first-order absorption adequately described the pharmacokinetic data. The buprenorphine blood concentration at 50% of maximum effect for the inhibition of disease progression was 0.77 ng/mL (95% confidence interval 0.32-1.2). The inclusion of natural disease remission described as a function of postnatal age significantly improved the model fit. CONCLUSIONS: A buprenorphine pharmacokinetic/pharmacodynamic model was successfully developed. The model could facilitate model-informed optimization of the buprenorphine dosing regimen in the treatment of neonatal opioid withdrawal syndrome.

Surfactant phospholipids act as molecular switches for premature induction of quorum sensing-dependent virulence in Pseudomonas aeruginosa.

The virulence behaviors of many Gram-negative bacterial pathogens are governed by quorum-sensing (QS), a hierarchical system of gene regulation that relies on population density by producing and detecting extracellular signaling molecules. Although extensively studied under in vitro conditions, adaptation of QS system to physiologically relevant host environment is not fully understood. In this study, we investigated the influence of lung environment on the regulation of Pseudomonas aeruginosa virulence factors by QS in a mouse model of acute pneumonia. When cultured under laboratory conditions in lysogeny broth, wild-type P. aeruginosa strain PAO1 began to express QS-regulated virulence factors elastase B (LasB) and rhamnolipids (RhlA) during transition from late-exponential into stationary growth phase. In contrast, during acute pneumonia as well as when cultured in mouse bronchial alveolar lavage fluids (BALF), exponential phase PAO1 bacteria at low population density prematurely expressed QS regulatory genes lasI-lasR and rhlI-rhlR and their downstream virulence genes lasB and rhlA. Further analysis indicated that surfactant phospholipids were the primary components within BALF that induced the synthesis of N-(3-oxododecanoyl)-L-homoserine lactone (C12-HSL), which triggered premature expression of LasB and RhlA. Both phenol extraction and phospholipase A2 digestion abolished the ability of mouse BALF to promote LasB and RhlA expression. In contrast, provision of the major surfactant phospholipid dipalmitoylphosphatidylcholine (DPPC) restored the expression of both virulence factors. Collectively, our study demonstrates P. aeruginosa modulates its QS to coordinate the expression of virulence factors during acute pneumonia by recognizing pulmonary surfactant phospholipids.

Suggestions for Model-Informed Precision Dosing to Optimize Neonatal Drug Therapy.

Evidence for dosing, efficacy, and safety of most medications used to treat neonates is sparse. Thus, dosing is usually derived by extrapolation from adult and pediatric pharmacologic data with scaling by body weight or body surface area. This may lead to drug dosing that is unsafe or ineffective. However, new strategies are being developed and studied to dose medications in critically ill neonates. Mass spectroscopy technology capable of quickly analyzing drug levels is readily available. Software that integrates population pharmacokinetics and pharmacodynamics with data from sparse samples from neonates allows for timely adjustments of dosing to achieve the desired effect while minimizing adverse outcomes. Some genetic polymorphisms that affect drug response in neonates have also been reported. This review highlights aspects of drug response and how it is impacted by prematurity, assesses pharmacogenomic studies in neonates, and offers suggestions for innovative pharmacokinetic/pharmacodynamic model-based approaches that combine population- or physiology-based pharmacology data, Bayesian analysis, and electronic decision support tools for precision dosing in neonates while illustrating examples where this approach can be used to optimize medical therapy in neonates. Barriers to implementing precision dosing in neonates and how to overcome them are also discussed.

Buprenorphine pharmacotherapy for the management of neonatal abstinence syndrome in methadone-exposed neonates.

We aimed to compare the outcomes of pharmacotherapy with either buprenorphine or methadone in infants treated for neonatal abstinence syndrome (NAS) secondary to intrauterine exposure to methadone. This is a multi-center, retrospective cohort study to assess length of treatment (LOT), hospital length of stay (LOS), and cumulative opioid exposure between infants treated with either methadone or buprenorphine for NAS secondary to in utero exposure to methadone. Infants delivered at a gestational age ≥35 weeks and a maternal history of opioid-use disorder and/or urine drug screen positive for methadone, and postnatal pharmacotherapy for NAS with either buprenorphine or methadone as first-line opioid replacement therapy, were eligible. Median LOT, LOS, and cumulative opioid exposure were compared between buprenorphine- and methadone-treated infants. A total of 156 infants (48 treated with buprenorphine and 108 with methadone) were identified. The median LOT and LOS for buprenorphine-treated infants was 8 and 13 days compared with 15 and 20 days for methadone-treated infants, respectively, P < .001 for both outcomes. Median cumulative opioid dose in morphine equivalents was 0.6 mg/kg for buprenorphine-treated infants vs 1.05 mg/kg for methadone-treated infants, P < .001. No adverse effects were noted among either group. Of infants treated with buprenorphine, 34 (71%) required the addition of adjunctive pharmacotherapy during the NICU stay, compared with 31 (32%) in the methadone-treated group, P = .0008. However, significantly fewer infants treated with buprenorphine required continuation of therapy beyond discharge as compared with those treated with methadone. The difference is most likely a reflection of the protocols used by the sites. In infants that required pharmacotherapy for NAS secondary to intrauterine exposure to methadone, treatment with buprenorphine, compared with methadone therapy, was associated with better outcomes. If confirmed with prospective data, buprenorphine could be considered first-line therapy for the two medication-assisted treatment regimens recommended by the American College of Obstetricians and Gynecologists.

Decreasing birth asphyxia: utility of statistical process control in a low-resource setting.

The neonatal period is a critical time for survival of the child. A disproportionate amount of neonatal deaths occur in low-resource countries and are attributable to perinatal events, especially birth asphyxia. This project aimed to reduce the incidence of birth asphyxia by 20% by June 2014 through training in neonatal resuscitation and improving the availability of resuscitation equipment in the delivery room in the National Hospital Abuja, Nigeria. A prospective, longitudinal study using statistical process control analytical methods was done enrolling babies delivered at the National Hospital Abuja. Low Apgar scores or birth asphyxia (defined a priori as any score <7 at 1, 5 and/or at 10 min) was assessed. To ensure reliability and validity of Apgar scoring, trainings on scoring were held for labour and delivery staff. Interventions included provision of additional equipment and trainings on neonatal resuscitation. Apgar scores were aggregated weekly over 25 months. Control charts with three SE confidence limits were used to monitor the proportion of scores ≤7. The baseline incidence of low Apgar scores, as defined a priori, was 33%, 17% and 10% while postintervention the incidence was 18%, 17% and 6% at 1, 5 and 10 min, respectively-a reduction of 45% and 40% in the 1-min and 10-min low Apgar scores. Increased communication, additional resuscitation equipment and training of delivery personnel on neonatal resuscitation are associated with reductions in measures of birth asphyxia. These improvements have been sustained and efforts are ongoing to spread our interventions to other special care delivery units/nursery in adjoining states. Our study demonstrates the feasibility and utility of using improvement science methods to assess and improve perinatal outcome in low-resource settings.

Lysozyme and bilirubin bind to ACE and regulate its conformation and shedding.

Angiotensin I-converting enzyme (ACE) hydrolyzes numerous peptides and is a critical participant in blood pressure regulation and vascular remodeling. Elevated tissue ACE levels are associated with increased risk for cardiovascular and respiratory disorders. Blood ACE concentrations are determined by proteolytic cleavage of ACE from the endothelial cell surface, a process that remains incompletely understood. In this study, we identified a novel ACE gene mutation (Arg532Trp substitution in the N domain of somatic ACE) that increases blood ACE activity 7-fold and interrogated the mechanism by which this mutation significantly increases blood ACE levels. We hypothesized that this ACE mutation disrupts the binding site for blood components which may stabilize ACE conformation and diminish ACE shedding. We identified the ACE-binding protein in the blood as lysozyme and also a Low Molecular Weight (LMW) ACE effector, bilirubin, which act in concert to regulate ACE conformation and thereby influence ACE shedding. These results provide mechanistic insight into the elevated blood level of ACE observed in patients on ACE inhibitor therapy and elevated blood lysozyme and ACE levels in sarcoidosis patients.

A Cohort Comparison of Buprenorphine versus Methadone Treatment for Neonatal Abstinence Syndrome.

OBJECTIVES: To compare the duration of opioid treatment and length of stay among infants treated for neonatal abstinence syndrome (NAS) by using a pilot buprenorphine vs conventional methadone treatment protocol. STUDY DESIGN: This retrospective cohort analysis evaluated infants who received pharmacotherapy for NAS at 6 hospitals in Southwest Ohio from January 2012 through August 2014. A single neonatology provider group used a standardized methadone protocol across all 6 hospitals. However, at one of the sites, infants were managed with a buprenorphine protocol unless they had experienced chronic in utero exposure to methadone. Linear mixed models were used to calculate adjusted mean duration of opioid treatment and length of inpatient hospitalization with 95% CIs in infants treated with oral methadone compared with sublingual buprenorphine. The use of adjunct therapy was examined as a secondary outcome. RESULTS: A total of 201 infants with NAS were treated with either buprenorphine (n = 38) or methadone (n = 163) after intrauterine exposure to short-acting opioids or buprenorphine. Buprenorphine therapy was associated with a shorter course of opioid treatment of 9.4 (CI 7.1-11.7) vs 14.0 (12.6-15.4) days (P < .001) and decreased hospital stay of 16.3 (13.7-18.9) vs 20.7 (19.1-22.2) days (P < .001) compared with methadone therapy. No difference was detected in the use of adjunct therapy (23.7% vs 25.8%, P = .79) between treatment groups. CONCLUSION: The choice of pharmacotherapeutic agent is an important determinant of hospital outcomes in infants with NAS. Sublingual buprenorphine may be superior to methadone for management of NAS in infants with select intrauterine opioid exposures.

Natural Anti-Infective Pulmonary Proteins: In Vivo Cooperative Action of Surfactant Protein SP-A and the Lung Antimicrobial Peptide SP-BN.

The anionic antimicrobial peptide SP-B(N), derived from the N-terminal saposin-like domain of the surfactant protein (SP)-B proprotein, and SP-A are lung anti-infective proteins. SP-A-deficient mice are more susceptible than wild-type mice to lung infections, and bacterial killing is enhanced in transgenic mice overexpressing SP-B(N). Despite their potential anti-infective action, in vitro studies indicate that several microorganisms are resistant to SP-A and SP-B(N). In this study, we test the hypothesis that these proteins act synergistically or cooperatively to strengthen each other's microbicidal activity. The results indicate that the proteins acted synergistically in vitro against SP-A- and SP-B(N)-resistant capsulated Klebsiella pneumoniae (serotype K2) at neutral pH. SP-A and SP-B(N) were able to interact in solution (Kd = 0.4 µM), which enabled their binding to bacteria with which SP-A or SP-B(N) alone could not interact. In vivo, we found that treatment of K. pneumoniae-infected mice with SP-A and SP-B(N) conferred more protection against K. pneumoniae infection than each protein individually. SP-A/SP-B(N)-treated infected mice showed significant reduction of bacterial burden, enhanced neutrophil recruitment, and ameliorated lung histopathology with respect to untreated infected mice. In addition, the concentrations of inflammatory mediators in lung homogenates increased early in infection in contrast with the weak inflammatory response of untreated K. pneumoniae-infected mice. Finally, we found that therapeutic treatment with SP-A and SP-B(N) 6 or 24 h after bacterial challenge conferred significant protection against K. pneumoniae infection. These studies show novel anti-infective pathways that could drive development of new strategies against pulmonary infections.

Vitamin D status of early preterm infants and the effects of vitamin D intake during hospital stay.

OBJECTIVES: To evaluate vitamin D (vitD) status in early preterm infants (EPTIs) at birth and during birth hospitalisation on current vitD intake. DESIGN/METHODS: Serum 25-hydroxyvitamin-D [25(OH)D] concentrations, vitD intake and risk factors for low vitD status were assessed in 120 infants born at ≤32 weeks gestation. RESULTS: Mean (SD) serum 25(OH)D at birth was 46.2 (14.0) nmol/L with lower concentrations in infants born <28 weeks than at 28-32 weeks gestation, p=0.02. Serum 25(OH)D was <50 nmol/L in 63% of mothers, 64% of infants at birth and 35% of infants at discharge. Mean daily vitD intake was 289±96 IU at 4 weeks of age and 60% achieved 400 IU/day intake at discharge. CONCLUSIONS: Serum 25(OH)D <50 nmol/L was widespread in parturient women and in EPTIs at birth and at discharge. Optimising maternal vitD status during pregnancy and improving postnatal vitD intake may enhance infant vitD status during hospitalisation.

Persistence of LPS-induced lung inflammation in surfactant protein-C-deficient mice.

Pulmonary surfactant protein-C (SP-C) gene-targeted mice (Sftpc(-/-)) develop progressive lung inflammation and remodeling. We hypothesized that SP-C deficiency reduces the ability to suppress repetitive inflammatory injury. Sftpc(+/+) and Sftpc(-/-) mice given three doses of bacterial LPS developed airway and airspace inflammation, which was more intense in the Sftpc(-/-) mice at 3 and 5 days after the final dose. Compared with Sftpc(+/+)mice, inflammatory injury persisted in the lungs of Sftpc(-/-) mice 30 days after the final LPS challenge. Sftpc(-/-) mice showed LPS-induced airway goblet cell hyperplasia with increased detection of Sam pointed Ets domain and FoxA3 transcription factors. Sftpc(-/-) type II alveolar epithelial cells had increased cytokine expression after LPS exposure relative to Sftpc(+/+) cells, indicating that type II cell dysfunction contributes to inflammatory sensitivity. Microarray analyses of isolated type II cells identified a pattern of enhanced expression of inflammatory genes consistent with an intrinsic low-level inflammation resulting from SP-C deficiency. SP-C-containing clinical surfactant extract (Survanta) or SP-C/phospholipid vesicles blocked LPS signaling through the LPS receptor (Toll-like receptor [TLR] 4/CD14/MD2) in human embryonic kidney 293T cells, indicating that SP-C blocks LPS-induced cytokine production by a TLR4-dependent mechanism. Phospholipid vesicles alone did not modify the TLR4 response. In vivo deficiency of SP-C leads to inflammation, increased cytokine production by type II cells, and persistent inflammation after repetitive LPS stimulation.

Fatty acids regulate stress resistance and virulence factor production for Listeria monocytogenes.

Fatty acids (FAs) are the major structural component of cellular membranes, which provide a physical and chemical barrier that insulates intracellular reactions from environmental fluctuations. The native composition of membrane FAs establishes the topological and chemical parameters for membrane-associated functions and is therefore modulated diligently by microorganisms especially in response to environmental stresses. However, the consequences of altered FA composition during host-pathogen interactions are poorly understood. The food-borne pathogen Listeria monocytogenes contains mostly saturated branched-chain FAs (BCFAs), which support growth at low pH and low temperature. In this study, we show that anteiso-BCFAs enhance bacterial resistance against phagosomal killing in macrophages. Specifically, BCFAs protect against antimicrobial peptides and peptidoglycan hydrolases, two classes of phagosome antimicrobial defense mechanisms. In addition, the production of the critical virulence factor, listeriolysin O, was compromised by FA modulation, suggesting that FAs play a key role in virulence regulation. In summary, our results emphasize the significance of FA metabolism, not only in bacterial virulence regulation but also in membrane barrier function by providing resistance against host antimicrobial stress.

Proteomic analysis of lamellar bodies isolated from amniotic fluid: implications for function.

Lamellar body count (LBC) in amniotic fluid is a well-established method for assessing fetal lung maturity. However, the biogenesis and function of lamellar bodies (LBs) secreted into the amniotic fluid have not been formally assessed. We purified LBs from amniotic fluids obtained from term gestation pregnancies that had been determined to have mature LBC. Using tandem mass spectrometry, we identified 122 unique proteins in the LB preparations from the amniotic fluids. There was minimal overlap between the proteins identified in amniotic fluid LB and those reported for human epidermis LB. In contrast, there was >40% concordance with the proteome of rat lung LBs despite species differences. Classification of the identified proteins into functional bins demonstrated that the preponderance of amniotic fluid LB proteins was associated with host defense or anti-inflammatory functions. These data suggest that amniotic fluid LBs are derived from lung secretions and may play an important role in innate host defense of the fetus.

Simvastatin is protective during Staphylococcus aureus pneumonia.

Epidemiologic studies suggest that the incidence and severity of sepsis are ameliorated in patients on statins (3- hydroxy-3-methylglutaryl coenzyme A reductase inhibitors) for cholesterol lowering indications. We sought to understand the mechanism underlying such protection and hypothesized that simvastatin would be protective in mice against acute infection with Staphylococcus aureus, the primary etiologic agent in sepsis. Mice were treated with simvastatin or buffer for two weeks and were subsequently challenged with S. aureus intratracheally or intravenously. Relative to buffer-treated mice, bacterial killing was enhanced 4-fold (p=0.02), systemic dissemination was reduced, and lethality was decreased (hazard ratio 8.8, 95% CI 2.5 to 31.3, p=0.001) in mice that were pretreated with simvastatin for two weeks. Systemic inflammatory response was abrogated and the local elaboration of inflammatory mediators was diminished. Serum concentrations of pro-fibrinolytic protein C were elevated (p=0.034), while the concentration of pro-coagulant tissue factor in bronchoalveolar lavage fluids was attenuated (reduced 25%), p=0.001, in simvastatin-treated mice. Taken together, these data indicate that extended treatment with simvastatin is protective during infection with S. aureus through enhanced bacterial clearance, anti-inflammatory, and anti-coagulant activities. These studies provide insights into the mechanism by which statins confer protection in acute infection, support the notion that statins may be effective adjuncts in the treatment of sepsis, and provide a rationale for randomized control trials in patients that are at a high risk for infection characterized by coagulopathy.

The Pseudomonas aeruginosa flagellum confers resistance to pulmonary surfactant protein-A by impacting the production of exoproteases through quorum-sensing.

Surfactant protein-A (SP-A) is an important antimicrobial protein that opsonizes and permeabilizes membranes of microbial pathogens in mammalian lungs. Previously, we have shown that Pseudomonas aeruginosa flagellum-deficient mutants are preferentially cleared in the lungs of wild-type mice by SP-A-mediated membrane permeabilization, and not by opsonization. In this study, we report a flagellum-mediated mechanism of P. aeruginosa resistance to SP-A. We discovered that flagellum-deficient (ΔfliC) bacteria are unable to produce adequate amounts of exoproteases to degrade SP-A in vitro and in vivo, leading to its preferential clearance in the lungs of SP-A(+/+) mice. In addition, ΔfliC bacteria failed to degrade another important lung antimicrobial protein lysozyme. Detailed analyses showed that ΔfliC bacteria are unable to upregulate the transcription of lasI and rhlI genes, impairing the production of homoserine lactones necessary for quorum-sensing, an important virulence process that regulates the production of multiple exoproteases. Thus, reduced ability of ΔfliC bacteria to quorum-sense attenuates production of exoproteases and limits degradation of SP-A, thereby conferring susceptibility to this major pulmonary host defence protein.

The effects of gestational age and birth weight on false-positive newborn-screening rates.

OBJECTIVE: Newborn-screening false-positive rates (FPRs) are disproportionately increased in preterm infants. The objective of this study was to determine variation in newborn screening FPRs according to birth weight and gestational age. Our secondary objective was to examine the effect of postnatal age on FPRs in preterm infants. METHODS: The Ohio State Newborn Screening Program Database was analyzed to determine the overall and birth weight-specific FPRs for 18 analytes. Data were stratified into birth weight categories (<1000 g, 1000-1499 g, 1500-2499 g, 2500-3999 g, and >4000 g). In addition, to examine the effect of postnatal age on FPRs, we examined the 2 analytes with the highest FPRs, thyrotropin with back-up thyroxine and 17-hydroxyprogesterone, in infants whose gestational age was <32 weeks, determined on the basis of postnatal age at screening. RESULTS: Data from 448 766 neonates were reviewed. Infants with very low birth weight (VLBW) comprised 1.9% of the study cohort, but accounted for 18% of false-positive results. For 14 of 18 analytes studied, FPRs increased with decreasing birth weight/gestational age and were significantly increased in infants with VLBW compared with infants who weighed 2500 to 3999 g (P < .001). Thyrotropin/back-up thyroxine and 17-hydroxyprogesterone accounted for 62% of total false-positive results in VLBW infants. When blood specimens were collected at a postnatal age of ≥ 48 hours in infants born at <32 weeks, a 44% relative reduction in 17-hydroxyprogesterone false-positive results was detected. CONCLUSIONS: False-positive newborn-screening rates are disproportionately increased in VLBW infants. FPRs may be reduced by delaying screening of <32 weeks' gestation, preterm infants until 24 to 48 hours' postnatal age.