Adolfo Llanos

The Mechanism of Excessive Intestinal Inflammation in Necrotizing Enterocolitis: An Immature Innate Immune Response

Necrotizing enterocolitis (NEC) is a devastating neonatal intestinal inflammatory disease, occurring primarily in premature infants, causing significant morbidity and mortality. The pathogenesis of NEC is associated with an excessive inflammatory IL-8 response. In this study, we hypothesized that this excessive inflammatory response is related to an immature expression of innate immune response genes. To address this hypothesis, intestinal RNA expression analysis of innate immune response genes was performed after laser capture microdissection of resected ileal epithelium from fetuses, NEC patients and children and confirmed in ex vivo human intestinal xenografts. Changes in mRNA levels of toll-like receptors (TLR)-2 and -4, their signaling molecules and transcription factors (MyD88, TRAF-6 and NFκB1) and negative regulators (SIGIRR, IRAK-M, A-20 and TOLLIP) and the effector IL-8 were characterized by qRT-PCR. The expression of TLR2, TLR4, MyD88, TRAF-6, NFκB1 and IL-8 mRNA was increased while SIGIRR, IRAK-M, A-20 and TOLLIP mRNA were decreased in fetal vs. mature human enterocytes and further altered in NEC enterocytes. Similar changes in mRNA expression were observed in immature, but not mature, human intestinal xenografts. Confirmation of gene expression was also validated with selective protein measurements and with suggested evidence that immature TRL4 enterocyte surface expression was internalized in mature enterocytes. Cortisone, an intestinal maturation factor, treatment corrected the mRNA differences only in the immature intestinal xenograft. Using specific siRNA to attenuate expression of primary fetal enterocyte cultures, both TOLLIP and A-20 were confirmed to be important when knocked down by exhibiting the same excessive inflammatory response seen in the NEC intestine. We conclude that the excessive inflammatory response of the immature intestine, a hallmark of NEC, is due to a developmental immaturity in innate immune response genes.

Community-based randomized double-blind study of gastrointestinal effects and copper exposure in drinking water

We assessed gastrointestinal effects in 1,365 adults exposed to either < 0.01 (controls), 2, 4, or 6 mg copper/L of drinking water for 2 months in a randomized, double-blind community-based study. The risk of symptoms increased with increasing Cu exposure and decreased with time. The best model by counting-process analysis included Cu concentration and sex. The risk of symptoms remained significantly higher in women than in men during weeks 1–4 for all concentrations tested; at week 1 comparison with the < 0.01-mg/L group showed that differences became significant in women at 4 mg/L [relative risk (RR) = 1.53; 95% confidence interval (CI), 1.02–2.05), and in men at 6 mg/L (RR = 1.9; 95% CI, 1.02–2.79). At week 2 for men and week 4 in women, the Cu concentration required to obtain significant differences on symptom report was > 6 mg Cu/L. We conclude that exposure to Cu in drinking water results in gastrointestinal symptoms, which are modulated by Cu concentration, time, and sex.

Compartmental analyses of 2H5-α-linolenic acid and C-U-eicosapentaenoic acid toward synthesis of plasma labeled 22:6n−3 in newborn term infants

BACKGROUND During early postnatal development, the nervous system accretes docosahexaenoic acid (DHA; 22:6n-3), a highly unsaturated n-3 (omega-3) fatty acid (FA) used in the formation of neural cell membranes. DHA, which is present in human breast milk, may also be biosynthesized from n-3 FAs such as 18:3n-3 [alpha-linolenic acid (ALA)] or 20:5n-3 [eicosapentaenoic acid (EPA)]. An important concern is to what extent these precursors can supply DHA to the developing infant. OBJECTIVE We analyzed measurements of fractional percentages of plasma (2)H(5)-ALA and (13)C-U-EPA directed toward the synthesis of labeled 22:6n-3 in 11 newborn infants by using compartmental modeling procedures. DESIGN One-week-old infants received doses of (2)H(5)-ALA and (13)C-U-EPA ethyl esters enterally. We drew blood from the infants periodically and analyzed the plasma for endogenous and labeled n-3 FAs. From the time-course concentrations of the labeled FAs, we determined rate constant coefficients, fractional synthetic rates, and plasma turnover rates of n-3 FAs. RESULTS In infants, approximately 0.04% of the (2)H(5)-ALA dose converted to plasma (2)H(5)-EPA. Plasma (2)H(5)-EPA and (2)H(5)-22:5n-3 [docosapentaenoic acid (DPA)] efficiently converted to (2)H(5)-DPA and (2)H(5)-DHA, respectively. The percentage of plasma (13)C-U-EPA directed toward the synthesis of (13)C-DHA was lower than the percentage of plasma (2)H(5)-EPA that originated from (2)H(5)-ALA. CONCLUSIONS Endogenously synthesized EPA was efficiently converted to DHA. In comparison, preformed EPA was less efficiently used for DHA biosynthesis, which suggests a differential metabolism of endogenous EPA compared with exogenous EPA. However, on a per mole basis, preformed EPA was 3.6 times more effective toward DHA synthesis than was ALA. Newborns required an intake of approximately 5 mg preformed DHA. kg(-1) x d(-1) to maintain plasma DHA homeostasis.

Infants with intrauterine growth restriction have impaired formation of docosahexaenoic acid in early neonatal life: a stable isotope study.

This study evaluated the arachidonic acid (AA) and docosahexaenoic acid (DHA) formation from d5-labeled linoleic acid (d5-LA) and α-linolenic acid (d5-LNA) precursors in infants with intrauterine growth restriction (IUGR) compared with control groups matched by gestational age (GA) or birth weight. We compared DHA and AA formation from deuterated precursors d5-LA and d5-LNA in 11 infants with IUGR with 13 and 25 control subjects who were appropriate for GA and matched by GA and by birth weight, respectively. After an enteral administration of d5-LA and d5-LNA, we determined unlabeled and d5-labeled fatty acids at 24, 48, and 96 h in plasma. Absolute concentrations and area under the curve (AUC) over the 96-h study were used for analysis. Absolute concentration of d5-DHA and the product/precursor ratio of the d5-labeled AUCs indicated a less active DHA formation from LNA in infants with IUGR compared with their GA-matched (2-fold) and birth weight–matched (3-fold) control subjects. The ratios of eicosapentaenoic and n-3 docosapentaenoic acid to DHA were also affected. Similar evaluation for the n-6 series was not significant. DHA metabolism is affected in infants with IUGR; the restricted DPA to DHA conversion step seems to be principally responsible for this finding.

Compartmental Analyses of Plasma 13C- and 2H-Labeled n-6 Fatty Acids Arising from Oral Administrations of 13C-U-18:2n-6 and 2H5-20:3n-6 in Newborn Infants

Efficacy of 13C-U-18:2n-6 and 2H5-20:3n-6 toward synthesis of labeled-20:4n-6 was studied in newborn infants utilizing compartmental models of plasma labeled n-6 fatty acids (FA). Ten infants received oral doses of 13C-U-18:2n-6 and 2H5-20:3n-6 ethyl esters (100 and 2 mg/kg, respectively). Rate constant coefficients and half-lives (t½) of n-6 FA were determined from the time-course concentrations of labeled-FA. Plasma n-6 FA values approximated steady state concentrations. Synthetic and utilization rates were calculated. Eight percent (range, 2–21%) of plasma 13C-U-18:2n-6 was used for synthesis of 13C-18:3n-6, -20:2n-6, and -20:3n-6. Seventy percent of 13C-20:3n-6 (mean, CV: 0.26) was available for synthesis of 13C-20:4n-6. The percentage of 2H5-20:3n-6 converted to 2H5-20:4n-6 was lower (mean: 26%, p < 0.02) than the 13C-labeled analogue. Turnover of 18:2n-6 in subjects and of 20:4n-6 in plasma was 4.2 g/kg/d (CV: 0.58) and 4.3 mg/kg/d (CV: 0.81), respectively. Intake of 18:2n-6 and 20:4n-6 were estimated to be 3.0 g/kg/d (±1.7) and 2.8 mg/kg/d (± 2.2), respectively. Infants required additional 18:2n-6 and 20:4n-6 (mean: 1.2 g and 1.5 mg/kg/d) above predicted intake amounts to maintain plasma concentrations of 18:2n-6 and 20:4n-6, in order to spare FA from fat stores.

Are research priorities in Latin America in line with the nutritional problems of the population

OBJECTIVE Concordance of nutritional research priorities with the related burden of disease is essential to develop cost-effective interventions to address the nutritional problems of populations. The present study aimed to evaluate whether nutrition research priorities are in agreement with the populations nutritional problems in Latin America. DESIGN The epidemiological profile was contrasted with the research priorities and research produced by academic institutions for each country. Qualitative analysis of research production by type of contribution to problem solving was also conducted. SETTINGS Nine Latin American countries. RESULTS Obesity (high body mass index (BMI)) and micronutrient deficiencies (anaemia) emerged as key problems, followed by stunting, breast-feeding/lactation and low birth weight. Wasting in children and women (low BMI) was uncommon. Concordance of ranked research priorities with the epidemiological profile of the country was generally good for nutrition-related chronic diseases, micronutrients and low birth weight, but not for undernutrition, stunting and breast-feeding. Studies on the efficacy and effectiveness of interventions were uncommon. CONCLUSIONS The present research agenda insufficiently supports the goal of public health nutrition, which is to ensure the implementation of cost-effective nutrition programmes and policies. A more rational approach to define research priorities is needed.

Dietary Essential Fatty Acids in Early Postnatal Life: Long-Term Outcomes

The formation of long-chain (LC) polyunsaturated fatty acids (PUFAs) from the parent essential fatty acids (EFAs) in early life is limited, thus infants are dependent on the exogenous provision of LC-PUFAs from human milk or supplemented formula. LC-PUFAs are structural components of all tissues, they are indispensable for cell membrane synthesis and for the function of key organelles such as mitochondria, endoplasmic reticulum and synaptic vesicles; and also for membrane receptors and signal transduction systems. The brain, retina and other neural tissues are particularly rich in LC-PUFAs; if diet is deficient in LC-PUFAs during early life, neural structural development and function are affected. LC-PUFAs also serve as specific precursors for 20-carbon eicosanoid production (prostaglandins, prostacyclins, thromboxanes, and leukotrienes). Recently docosanoids derived from 22-carbon LC-PUFAs have been identified and their capacity to protect neural tissue from hypoxia-reperfusion injury characterized. Eicosanoids and docosanoids act as autocrine and paracrine mediators. They are powerful regulators of numerous cell and tissue functions (e.g. thrombocyte aggregation, inflammatory reactions and leukocyte functions, cytokine release and action, vasoconstriction and vasodilatation, blood pressure control, bronchial constriction, and uterine contraction). Hornstra G, Uauy R, Yang X (eds): The Impact of Maternal Nutrition on the Offspring. Nestlé Nutrition Workshop Series Pediatric Program, vol 55, pp 101–136, Nestec Ltd., Vevey/S. Karger AG, Basel,

Cost-Effectiveness of a Folic Acid Fortification Program in Chile: TL018

Background: Periconceptional intakes of folic acid (FA) reduce the risk of having a fetus affected anencephaly and spina bifida by 50-70%. The Chilean Ministry of Health mandated fortification of wheat flour at a level of 2.2 mg/FA/kg starting January 2000. This fortification policy served to increase intake of FA by 427 mcg/d that was associated to an overall 43% reduction in the incidence of neural tube defects (NTD) affected pregnancies. An economic evaluation of the program should provide useful information.Methods: We compared the strategy of fortification with no fortification. Estimation of incremental cost per case averted (C/E ratios) were done extrapolating the incidence risk reduction from program evaluation to the total number of live births and fetal deaths occurring in 2001. C/E ranges were presented for the 95% confidence interval of risk reduction. Economic benefits to the averted costs resulting from preventing births with NTDs (medical and rehabilitation long term cost) in a one-year birth cohort were calculated.Results: The one year program cost was I

Epidemiology of Neonatal Necrotizing Enterocolitis in the Post-Surfactant Era:A Population-Based Study

447.700.Case averted and cost (expressed in International Dollars (I

Term infant studies of DHA and ARA supplementation on neurodevelopment: results of randomized controlled trials

) per case averted were:The cost per DALYs averted without and with 3% discount was 46 (44-67) and 119 (109 -166) I