GDF15 linked to maternal risk of nausea and vomiting during pregnancy.

GDF15, a hormone acting on the brainstem, has been implicated in the nausea and vomiting of pregnancy, including its most severe form, hyperemesis gravidarum (HG), but a full mechanistic understanding is lacking1-4. Here we report that fetal production of GDF15 and maternal sensitivity to it both contribute substantially to the risk of HG. We confirmed that higher GDF15 levels in maternal blood are associated with vomiting in pregnancy and HG. Using mass spectrometry to detect a naturally labelled GDF15 variant, we demonstrate that the vast majority of GDF15 in the maternal plasma is derived from the feto-placental unit. By studying carriers of rare and common genetic variants, we found that low levels of GDF15 in the non-pregnant state increase the risk of developing HG. Conversely, women with ß-thalassaemia, a condition in which GDF15 levels are chronically high5, report very low levels of nausea and vomiting of pregnancy. In mice, the acute food intake response to a bolus of GDF15 is influenced bi-directionally by prior levels of circulating GDF15 in a manner suggesting that this system is susceptible to desensitization. Our findings support a putative causal role for fetally derived GDF15 in the nausea and vomiting of human pregnancy, with maternal sensitivity, at least partly determined by prepregnancy exposure to the hormone, being a major influence on its severity. They also suggest mechanism-based approaches to the treatment and prevention of HG.

Maternal serum concentrations of bisphenol A and propyl paraben in early pregnancy are associated with male infant genital development.

STUDY QUESTION: Are maternal serum phthalate metabolite, phenol and paraben concentrations measured at 10-17 weeks of gestation associated with male infant genital developmental outcomes, specifically cryptorchidism, anogenital distance (AGD), penile length and testicular descent distance, at birth and postnatally? SUMMARY ANSWER: Maternal serum bisphenol A (BPA) concentration at 10-17 weeks of gestation was positively associated with congenital or postnatally acquired cryptorchidism, and n-propyl paraben (n-PrP) concentration was associated with shorter AGD from birth to 24 months of age. WHAT IS KNOWN ALREADY: Male reproductive disorders are increasing in prevalence, which may reflect environmental influences on foetal testicular development. Animal studies have implicated phthalates, BPA and parabens, to which humans are ubiquitously exposed. However, epidemiological studies have generated conflicting results and have often been limited by small sample size and/or measurement of chemical exposures outside the most relevant developmental window. STUDY DESIGN, SIZE, DURATION: Case-control study of cryptorchidism nested within a prospective cohort study (Cambridge Baby Growth Study), with recruitment of pregnant women at 10-17 postmenstrual weeks of gestation from a single UK maternity unit between 2001 and 2009 and 24 months of infant follow-up. Of 2229 recruited women, 1640 continued with the infancy study after delivery, of whom 330 mothers of 334 male infants (30 with congenital cryptorchidism, 25 with postnatally acquired cryptorchidism and 279 unmatched controls) were included in the present analysis. PARTICIPANTS/MATERIALS, SETTING, METHODS: Maternal blood was collected at enrolment, and serum levels of 16 phthalate metabolites, 9 phenols (including BPA) and 6 parabens were measured using liquid chromatography/tandem mass spectrometry. Logistic regression was used to model the association of cryptorchidism with serum chemical concentrations, adjusting for putative confounders. Additionally, offspring AGD, penile length and testicular descent distance were assessed at 0, 3, 12, 18 and 24 months of age, and age-specific Z scores were calculated. Associations between serum chemical levels and these outcomes were tested using linear mixed models. MAIN RESULTS AND THE ROLE OF CHANCE: Maternal serum BPA concentration was associated with offspring all-type cryptorchidism both when considered as a continuous exposure (adjusted odds ratio per log10 µg/l: 2.90, 95% CI 1.31-6.43, P = 0.009) and as quartiles (phet = 0.002). Detection of n-PrP in maternal serum was associated with shorter AGD (by 0.242 standard deviations, 95% CI 0.051-0.433, P = 0.01) from birth to 24 months of age; this reduction was independent of body size and other putative confounders. We did not find any consistent associations with offspring outcomes for the other phenols, parabens, and phthalate metabolites measured. LIMITATIONS, REASONS FOR CAUTION: We cannot discount confounding by other demographic factors or endocrine-disrupting chemicals. There may have been misclassification of chemical exposure due to use of single serum measurements. The cohort was not fully representative of pregnant women in the UK, particularly in terms of smoking prevalence and maternal ethnicity. WIDER IMPLICATIONS OF THE FINDINGS: Our observational findings support experimental evidence that intrauterine exposure to BPA and n-PrP during early gestation may adversely affect male reproductive development. More evidence is required before specific public health recommendations can be made. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by a European Union Framework V programme, the World Cancer Research Fund International, the Medical Research Council (UK), Newlife the Charity for Disabled Children, the Mothercare Group Foundation, Mead Johnson Nutrition and the National Institute for Health Research Cambridge Comprehensive Biomedical Research Centre. Visiting Fellowship (J.M.): Regional Programme 'Jiménez de la Espada' for Research Mobility, Cooperation and Internationalization, Seneca Foundation-Science and Technology Agency for the Region of Murcia (No. 20136/EE/17). K.O. is supported by the Medical Research Council (UK) (Unit Programme number: MC_UU_12015/2). The authors declare no conflict of interest.

Which infancy growth parameters are associated with later adiposity? The Cambridge Baby Growth Study.

Background: Highly consistent positive associations are reported between infancy growth and later obesity risk. However, it is unclear whether infancy growth parameters beyond body weight add to the prediction of later obesity risk.Aim: To assess whether infancy length and skinfold thicknesses add to infancy weight in the prediction of childhood adiposity.Subjects and methods: This analysis included 254 children with available data on infant growth from birth to 24 months and childhood adiposity at age 6-11 years measured by DXA. Multilevel linear regression was used to examine the predictors of childhood percent body fat (%BF), with adjustment for sex and age at follow-up visit.Results: Birth weight and weight gain (modelled as changes in z-score) between 0-3 months and 3-24 months showed independent positive relationships with childhood %BF. The addition of gains in infant length and skinfolds between 0-3 months, but not 3-24 months, improved overall model prediction, from 18.7% to 20.7% of the variance in childhood %BF (likelihood ratio test, p < 0.0001), although their independent effect estimates were small (infant length gain: negative trend, partial R-square 0.6%, p = 0.2; skinfolds: positive trend, 1.3%, p = 0.09).Conclusion: Infancy length and skinfolds contribute significantly, but only modestly, to the prediction of childhood adiposity.

The EndoPredict score provides prognostic information on late distant metastases in ER+/HER2- breast cancer patients.

BACKGROUND: ER+/HER2- breast cancers have a proclivity for late recurrence. A personalised estimate of relapse risk after 5 years of endocrine treatment can improve patient selection for extended hormonal therapy. METHODS: A total of 1702 postmenopausal ER+/HER2- breast cancer patients from two adjuvant phase III trials (ABCSG6, ABCSG8) treated with 5 years of endocrine therapy participated in this study. The multigene test EndoPredict (EP) and the EPclin score (which combines EP with tumour size and nodal status) were predefined in independent training cohorts. All patients were retrospectively assigned to risk categories based on gene expression and on clinical parameters. The primary end point was distant metastasis (DM). Kaplan-Meier method and Cox regression analysis were used in an early (0-5 years) and late time interval (>5 years post diagnosis). RESULTS: EP is a significant, independent, prognostic parameter in the early and late time interval. The expression levels of proliferative and ER signalling genes contribute differentially to the underlying biology of early and late DM. The EPclin stratified 64% of patients at risk after 5 years into a low-risk subgroup with an absolute 1.8% of late DM at 10 years of follow-up. CONCLUSION: The EP test provides additional prognostic information for the identification of early and late DM beyond what can be achieved by combining the commonly used clinical parameters. The EPclin reliably identified a subgroup of patients who have an excellent long-term prognosis after 5 years of endocrine therapy. The side effects of extended therapy should be weighed against this projected outcome.

EndoPredict improves the prognostic classification derived from common clinical guidelines in ER-positive, HER2-negative early breast cancer.

BACKGROUND: In early estrogen receptor (ER)-positive/HER2-negative breast cancer, the decision to administer chemotherapy is largely based on prognostic criteria. The combined molecular/clinical EndoPredict test (EPclin) has been validated to accurately assess prognosis in this population. In this study, the clinical relevance of EPclin in relation to well-established clinical guidelines is assessed. PATIENTS AND METHODS: We assigned risk groups to 1702 ER-positive/HER2-negative postmenopausal women from two large phase III trials treated only with endocrine therapy. Prognosis was assigned according to National Comprehensive Cancer Center Network-, German S3-, St Gallen guidelines and the EPclin. Prognostic groups were compared using the Kaplan-Meier survival analysis. RESULTS: After 10 years, absolute risk reductions (ARR) between the high- and low-risk groups ranged from 6.9% to 11.2% if assigned according to guidelines. It was at 18.7% for EPclin. EPclin reassigned 58%-61% of women classified as high-/intermediate-risk (according to clinical guidelines) to low risk. Women reclassified to low risk showed a 5% rate of distant metastasis at 10 years. CONCLUSION: The EPclin score is able to predict favorable prognosis in a majority of patients that clinical guidelines would assign to intermediate or high risk. EPclin may reduce the indications for chemotherapy in ER-positive postmenopausal women with a limited number of clinical risk factors.

RNA-based determination of ESR1 and HER2 expression and response to neoadjuvant chemotherapy.

BACKGROUND: Hormone and human epidermal growth factor receptor 2 (HER2) receptors are the most important breast cancer biomarkers, and additional objective and quantitative test methods such as messenger RNA (mRNA)-based quantitative analysis are urgently needed. In this study, we investigated the clinical validity of RT-PCR-based evaluation of estrogen receptor (ESR1) and HER2 mRNA expression. PATIENTS AND METHODS: A total of 1050 core biopsies from two retrospective (GeparTrio, GeparQuattro) and one prospective (PREDICT) neoadjuvant studies were evaluated by quantitative RT-PCR for ESR1 and HER2. RESULTS: ESR1 mRNA was significantly predictive for reduced response to neoadjuvant chemotherapy in univariate and multivariate analysis in all three cohorts. The complete pathologically documented response (pathological complete response, pCR) rate for ESR1+/HER2- tumors was 7.3%, 8.0% and 8.6%; for ESR1-/HER2- tumors it was 34.4%, 33.7% and 37.3% in GeparTrio, GeparQuattro and PREDICT, respectively (P < 0.001 in each cohort). In the Kaplan-Meier analysis in GeparTrio patients with ESR1+/HER2- tumors had the best prognosis, compared with ESR1-/HER2- and ESR1-/HER2+ tumors [disease-free survival (DFS): P < 0.0005, overall survival (OS): P < 0.0005]. CONCLUSIONS: Our results suggest that mRNA levels of ESR1 and HER2 predict response to neoadjuvant chemotherapy and are significantly associated with long-term outcome. As an additional option to standard immunohistochemistry and gene-array-based analysis, quantitative RT-PCR analysis might be useful for determination of the receptor status in breast cancer.

Fetally-encoded GDF15 and maternal GDF15 sensitivity are major determinants of nausea and vomiting in human pregnancy.

Human pregnancy is frequently accompanied by nausea and vomiting that may become severe and life-threatening, as in hyperemesis gravidarum (HG), the cause of which is unknown. Growth Differentiation Factor-15 (GDF15), a hormone known to act on the hindbrain to cause emesis, is highly expressed in the placenta and its levels in maternal blood rise rapidly in pregnancy. Variants in the maternal GDF15 gene are associated with HG. Here we report that fetal production of GDF15, and maternal sensitivity to it, both contribute substantially to the risk of HG. We found that the great majority of GDF15 in maternal circulation is derived from the feto-placental unit and that higher GDF15 levels in maternal blood are associated with vomiting and are further elevated in patients with HG. Conversely, we found that lower levels of GDF15 in the non-pregnant state predispose women to HG. A rare C211G variant in GDF15 which strongly predisposes mothers to HG, particularly when the fetus is wild-type, was found to markedly impair cellular secretion of GDF15 and associate with low circulating levels of GDF15 in the non-pregnant state. Consistent with this, two common GDF15 haplotypes which predispose to HG were associated with lower circulating levels outside pregnancy. The administration of a long-acting form of GDF15 to wild-type mice markedly reduced subsequent responses to an acute dose, establishing that desensitisation is a feature of this system. GDF15 levels are known to be highly and chronically elevated in patients with beta thalassemia. In women with this disorder, reports of symptoms of nausea or vomiting in pregnancy were strikingly diminished. Our findings support a causal role for fetal derived GDF15 in the nausea and vomiting of human pregnancy, with maternal sensitivity, at least partly determined by pre-pregnancy exposure to GDF15, being a major influence on its severity. They also suggest mechanism-based approaches to the treatment and prevention of HG.

Animal and translational models of SARS-CoV-2 infection and COVID-19.

COVID-19 is causing a major once-in-a-century global pandemic. The scientific and clinical community is in a race to define and develop effective preventions and treatments. The major features of disease are described but clinical trials have been hampered by competing interests, small scale, lack of defined patient cohorts and defined readouts. What is needed now is head-to-head comparison of existing drugs, testing of safety including in the background of predisposing chronic diseases, and the development of new and targeted preventions and treatments. This is most efficiently achieved using representative animal models of primary infection including in the background of chronic disease with validation of findings in primary human cells and tissues. We explore and discuss the diverse animal, cell and tissue models that are being used and developed and collectively recapitulate many critical aspects of disease manifestation in humans to develop and test new preventions and treatments.

[Predictive and prognostic markers of breast cancer. Molecular biological analysis of fixed tumor tissue]. / Prädiktive und prognostische Brustkrebsmarker. Molekularbiologische Analyse von fixiertem Tumorgewebe als Basis.

A multitude of prognostic and predictive multiparameter algorithms based on the analysis of mRNA have been published in recent years. Many of the algorithms require fresh or fresh frozen tissue as a source of the mRNA. However, practical considerations suggest formalin-fixed paraffin-embedded tissue (FFPE tissue) to be a more suitable starting material for routine diagnostic applications. Therefore, Siemens Healthcare Diagnostics is developing a fully automated method to extract mRNA and DNA from FFPE tissue for use in pathology laboratories. Initially, the method will be used as part of a prognosis assay to predict the likelihood of distant metastasis and death for node-negative breast cancer patients.

Associations between a fetal imprinted gene allele score and late pregnancy maternal glucose concentrations.

AIM: We hypothesised that some of the genetic risk for gestational diabetes (GDM) is due to the fetal genome affecting maternal glucose concentrations. Previously, we found associations between fetal IGF2 gene variants and maternal glucose concentrations in late pregnancy. METHODS: In the present study, we tested associations between SNP alleles from 15 fetal imprinted genes and maternal glucose concentrations in late pregnancy in the Cambridge Baby Growth and Wellbeing cohorts (1160 DNA trios). RESULTS: Four fetal SNP alleles with the strongest univariate associations: paternally-transmitted IGF2 rs10770125 (P-value=2×10-4) and INS rs2585 (P-value=7×10-4), and maternally-transmitted KCNQ1(OT1) rs231841 (P-value=1×10-3) and KCNQ1(OT1) rs7929804 (P-value=4×10-3), were used to construct a composite fetal imprinted gene allele score which was associated with maternal glucose concentrations (P-value=4.3×10-6, n=981, r2=2.0%) and GDM prevalence (odds ratio per allele 1.44 (1.15, 1.80), P-value=1×10-3, n=89 cases and 899 controls). Meta-analysis of the associations including data from 1367 Hyperglycaemia and Adverse Pregnancy Outcome Study participants confirmed the paternally-transmitted fetal IGF2/INS SNP associations (rs10770125, P-value=3.2×10-8, rs2585, P-value=3.6×10-5) and the composite fetal imprinted gene allele score association (P-value=1.3×10-8), but not the maternally-transmitted fetal KCNQ1(OT1) associations (rs231841, P-value=0.4; rs7929804, P-value=0.2). CONCLUSION: This study suggests that polymorphic variation in fetal imprinted genes, particularly in the IGF2/INS region, contribute a small but significant part to the risk of raised late pregnancy maternal glucose concentrations.

Biomonitoring the genotoxic potential of the air on Tradescantia pallida var. purpurea under climatic conditions in the Sinos River basin, Rio Grande do Sul, Brazil.

The present study evaluated the genotoxic effects of the atmospheric air on Tradescantia pallida var. purpurea in urban areas with different intensities of vehicular traffic and in riparian forest fragments in the Sinos River Basin (Rio Grande do Sul, Brazil), considering the influence of climatic conditions prevailing in these environments. Bimonthly, from May 2012 to March 2013, cuttings with flower buds were exposed for 8 h in urban and riparian forest environments in the municipalities of Caraá, Taquara and Campo Bom in the upper, middle and lower sections, respectively, of the Sinos River Basin. Simultaneously, negative controls were made and climatic data were recorded. Micronuclei (MCN) frequencies were determined in young tetrads of pollen mother cells and expressed as MCN/100 tetrads. Significantly higher MCN frequencies were observed in buds exposed in urban and riparian forest environments in Taquara (up to 7.23 and 4.80, respectively) and Campo Bom (up to 4.90 and 4.23, respectively) than in buds exposed in Caraá (up to 2.90 and 2.50, respectively), in the majority of samplings, and in relation to the negative control (up to 1.93) in all months. Over the course of the period monitored, there were significant variations in MCN frequencies at all sampling points, with the exception of the urban environment in Caraá. For the urban environments, relation between the MCN frequency, vehicular traffic and mean temperature was observed. For the riparian forest fragments, there was no association between MCN frequency and climatic factors. Tradescantia pallida var. purpurea can be considered a useful tool to point out areas with increased atmospheric pollution, since the exposure of plants under severe climatic conditions is avoided to minimize their negative influence on the formation of micronuclei.

Integrated Environmental Assessment of streams in the Sinos River basin in the state of Rio Grande do Sul, Brazil.

The deterioration of environmental quality in the Sinos River basin is directly associated with the impacts of intense industrialization and urbanization. An integrated environmental assessment (IEA) was conducted in July and September of 2012, in areas along the sources of the EstânciaVelha/Portão, Pampa and Schmidt streams using physical, chemical and biological methods. The water in the three sampling sites was not proper for human consumption, presented a low toxic contamination index (TCI) and mesotrophic characteristics. One site was included in Class 4, and two, in Class 3, according to current legislation. The rapid assessment protocol (RAP) indicated a natural environmental condition for habitat diversity and environmental impact in the three sites. The Tradescantia pallida (Rose) D.R. Hunt var. purpurea Boom biomarker showed water genotoxicity in two of the sites. The integrated diagnosis of water quality in these streams is fundamentally important to ensure the sustainable management of water resources and their multiple uses, as well to estimate their contribution to pollution in this river basin.

Dissection of the metabolic actions of insulin in adipocytes from early growth-retarded male rats.

Numerous studies have shown a relationship between early growth restriction and Type 2 diabetes. Studies have shown that offspring of rats fed a low protein (LP) diet during pregnancy and lactation have a worse glucose tolerance in late adult life compared with controls. In contrast, in young adult life LP offspring have a better glucose tolerance which is associated with increased insulin-stimulated glucose uptake into skeletal muscle. The aim of the present study was to compare the regulation of glucose uptake and lipolysis in adipocytes by insulin in control and LP offspring. LP adipocytes had increased basal and insulin-stimulated glucose uptake compared with controls. There was no difference in basal rates of lipolysis. Isoproterenol stimulated lipolysis in both groups, but it was more effective on LP adipocytes. Insulin reduced lipolytic rates in controls to basal levels but had a reduced effect in LP adipocytes. Protein kinase B activity matched glucose uptake, with LP adipocytes having elevated activities. These results suggest that early growth retardation has long-term effects on adipocyte metabolism. In addition, they show selective resistance to different metabolic actions of insulin and provide insight into the mechanisms by which insulin regulates glucose uptake and lipolysis.

Early growth restriction leads to down regulation of protein kinase C zeta and insulin resistance in skeletal muscle.

Epidemiological studies have revealed a relationship between early growth restriction and the subsequent development of type 2 diabetes. A rat model of maternal protein restriction has been used to investigate the mechanistic basis of this relationship. This model causes insulin resistance and diabetes in adult male offspring. The aim of the present study was to determine the effect of early growth restriction on muscle insulin action in late adult life. Rats were fed either a 20% or an isocaloric 8% protein diet during pregnancy and lactation. Offspring were weaned onto a 20% protein diet and studied at 15 Months of age. Soleus muscle from growth restricted offspring (LP) (of dams fed 8% protein diet) had similar basal glucose uptakes compared with the control group (mothers fed 20% protein diet). Insulin stimulated glucose uptake into control muscle but had no effect on LP muscle. This impaired insulin action was not related to changes in expression of either the insulin receptor or glucose transporter 4 (GLUT 4). However, LP muscle expressed significantly less (P<0.001) of the zeta isoform of protein kinase C (PKC zeta) compared with controls. This PKC isoform has been shown to be positively involved in GLUT 4-mediated glucose transport. Expression levels of other isoforms (betaI, betaII, epsilon, theta) of PKC were similar in both groups. These results suggest that maternal protein restriction leads to muscle insulin resistance. Reduced expression of PKC zeta may contribute to the mechanistic basis of this resistance.

Increased N-glycosylation and reduced transferrin-binding capacity of transferrin receptor isolated from placentae of diabetic women.

Infants of diabetic mothers are frequently born iron deficient because their fetal iron demand exceeds placental iron transport capacity. Although transferrin receptor (TfR) expression is increased, binding to diferric transferrin is decreased proportionately to the severity of maternal disease. It is hypothesized that TfR isolated from diabetic placentae has altered N-glycosylation since proper glycosylation of N-linked oligosaccharides is important for normal TfR binding kinetics to diferric transferrin. TfR was obtained from syncytiotrophoblastic membranes of six diabetic and six non-diabetic human placentae. Competitive binding to 125I-transferrin demonstrated a higher Kd in the diabetic TfR (P = 0.04), directly correlated to cord serum C-peptide concentration (r = 0.81, P < 0.001). The molecular weight of the monomeric form of TfR prior to treatment with glycopeptidase F (PNG-F) was greater in the diabetic group (P < 0.001) was directly related to the Kd (r = 0.77, P = 0.002). Treatment with PNG-F eliminated the molecular weight difference between the two groups. Increased glycosylation of the N-linked oligosaccharides of TfR isolated from diabetic placentae may alter the three-dimensional structure or charge of the receptor, thus reducing its binding affinity for transferrin.

Programming of intermediary metabolism.

Studies of animal models were carried out to explore mechanisms that might underlie epidemiological findings linking indices of poor early (fetal and early postnatal) growth to an increased risk of developing poor glucose tolerance, including the metabolic syndrome, in adult life. Adult obesity was also seen to play an important role in adding to these risks. We proposed the 'thrifty phenotype' hypothesis to provide a conceptual and mechanistic framework that could be tested by experimentation in animal models. Our main approach has been to feed a reduced protein diet to pregnant and/or lactating rat dams as a means of reducing growth in the fetal and/or preweaning stages of pup growth. Animals were weaned onto either a normal diet or an obesity-inducing highly palatable, cafeteria-style diet. Alterations in intermediary metabolism were noted in the rats with early growth restriction, which provide support for our hypothesis and clues to the mechanism.

Ketosis resistance in the male offspring of protein-malnourished rat dams.

Plasma beta-hydroxybutyrate concentrations were measured in the offspring of rats that were fed either a control (20% protein) diet or low-protein (8% protein) diet during pregnancy and lactation. Low-protein offspring had significantly lower plasma beta-hydroxybutyrate compared with controls in the fed state (P < .04) and after fasting for 24 hours (P < .001) and 48 hours (P < .04). There were no differences in blood glucose, acetoacetate, plasma glucagon, cholesterol, or glycerol between control and low-protein offspring. However, plasma nonesterified fatty acids (NEFAs) were significantly higher in low-protein offspring in the fed state (P < .05). In contrast, plasma triglycerides and insulin were significantly lower in low-protein offspring compared with controls when fed (P < .001) and after a 24-hour fast (P < .001). These results suggest that poor maternal and early postnatal nutrition can have long-term effects on ketone body metabolism in the offspring during adulthood. This apparent ketosis resistance is similar to that observed in some forms of human diabetes.

Effects of maternal iron restriction in the rat on blood pressure, glucose tolerance, and serum lipids in the 3-month-old offspring.

Epidemiologic studies have demonstrated associations between low birth weight and increased rates of adult diseases such as hypertension and diabetes. Maternal iron restriction in the rat has been reported to both reduce birth weight and to elevate blood pressure at 40 days of age. The aim of the present study was to extend these findings to investigate the effects of maternal iron restriction on glucose tolerance and serum lipids, 2 important components of the metabolic syndrome, in adult offspring. Blood pressure, glucose tolerance, and serum lipids were measured in the 3-month-old offspring of iron-restricted dams. Rats were placed on control or iron-restricted diets 1 week before mating. At term, dams on the iron-restricted diet were anemic with decreased haemoglobin, red blood cell (RBC) count, hematocrit, and mean RBC volume compared with controls. Neonates from iron-restricted litters were more severely anemic than the dams. At birth, body weight was lower in the offspring of iron-restricted dams than in controls and was still decreased at 3 months of age. At this same age, systolic blood pressure was significantly elevated in the offspring of iron-restricted dams. Glucose tolerance was improved in the maternal iron-restricted group. Fasting serum insulin levels were not different between the control and maternal iron-restricted groups. Fasting serum triglyceride was decreased in the offspring of iron-restricted dams compared with controls. Fasting serum cholesterol and free fatty acid concentrations were similar in both groups. These results suggest that maternal iron restriction has long-term effects on physiology and metabolism in the offspring. Some of these findings are comparable to those reported for the maternal protein-restriction model. It is thus speculated that the long-term effects of maternal dietary restriction may result from common fetal metabolic responses to this restriction.

Early growth restriction, membrane phospholipid fatty acid composition, and insulin sensitivity.

An animal model of protein restriction during pregnancy and lactation with subsequent dietary fatty acid manipulation was used to investigate the association between poor early growth, defective unsaturated fatty acid handling, and later disease. Both control and early growth-restricted animals fed a diet rich in saturated fatty acids showed a doubling of the plasma insulin levels as well as a reduced degree of unsaturation in liver and skeletal muscle membrane phospholipids compared with animals fed diets rich in unsaturated fatty acids. The skeletal muscle of early growth-restricted animals weaned onto a saturated fat diet had reduced proportions of 22:6n-3 and increased proportions of 18:1n-9. This reduction in 22:6n-3 is similar to that observed in Pima Indians, a population with a high prevalence of type 2 diabetes.

Contraction-induced increase in Vmax of palmitate uptake and oxidation in perfused skeletal muscle.

To evaluate the effects of contractions on the kinetics of uptake and oxidation of palmitate in a physiological muscle preparation, rat hindquarters were perfused with glucose (6 mmol/l), albumin-bound [1-14C]palmitate, and varying amounts of albumin-bound palmitate (200-2,200 micro mol/l) at rest and during muscle contractions. When plotted against the unbound palmitate concentration, palmitate uptake and oxidation displayed simple Michaelis-Menten kinetics with estimated maximal velocity (Vmax) and Michaelis-Menten constant (Km) values of 42.8 +/- 3.8 (SE) nmol . min-1 . g-1 and 13.4 +/- 3.4 nmol/l for palmitate uptake and 3.8 +/- 0.4 nmol . min-1 . g-1 and 8.1 +/- 2.9 nmol/l for palmitate oxidation, respectively, at rest. Whereas muscle contractions increased the Vmax for both palmitate uptake and oxidation to 91.6 +/- 10.1 and 16.5 +/- 2.3 nmol . min-1 . g-1, respectively, the Km remained unchanged. Vmax and Km estimates obtained from Hanes-Woolf plots (substrate concentration/velocity vs. substrate concentration) were not significantly different. In the resting perfused hindquarter, an increase in palmitate delivery from 31.9 +/- 0.9 to 48.7 +/- 1.2 micro mol . g-1 . h-1 by increasing perfusate flow was associated with a decrease in the fractional uptake of palmitate so that the rates of uptake and oxidation of palmitate remained unchanged. It is concluded that the rates of uptake and oxidation of long-chain fatty acids (LCFA) saturate with an increase in the concentration of unbound LCFA in perfused skeletal muscle and that muscle contractions, but not an increase in plasma flow, increase the Vmax for LCFA uptake and oxidation. The data are consistent with the notion that uptake of LCFA in muscle may be mediated in part by a transport system.