Post-weaning protein malnutrition induces myocardial dysfunction associated with oxidative stress and altered calcium handling proteins in adult rats.

Hypercaloric low-protein diet may lead to a state of malnutrition found in the low-income population of Northeastern Brazil. Although malnutrition during critical periods in the early life is associated with cardiovascular diseases in adulthood, the mechanisms of cardiac dysfunction are still unclear. Here we studied the effects of post-weaning malnutrition due to low protein intake induced by a regional basic diet on the cardiac contractility of young adult rats. In vivo arterial hemodynamic and in vitro myocardial contractility were evaluated in 3-month-old rats. Additionally, protein content of the sarcoplasmic reticulum Ca(2+)-ATPase (SERCA), total phospholamban (PLB) and phosphorylated at serine 16 (p-Ser(16)-PLB), α2-subunit of the Na(+)/K(+)-ATPase (α2-NKA), and Na(+)/Ca(2+) exchanger (NXC) and in situ production of superoxide anion (O2(-)) were measured in the heart. Blood pressure and heart rate increased in the post-weaning malnourished (PWM) rats. Moreover, malnutrition decreased twitch force and inotropic responses of the isolated cardiac muscle. Protein expression of SERCA, PLB/SERCA, and p-Ser(16)-PLB/PLB ratios and α2-NKA were decreased without changing NCX. The contraction dependent on transsarcolemmal calcium influx was unchanged but responsiveness to Ca(2+) and tetanic peak contractions were impaired in the PWM group. Myocardial O2(-) production was significantly increased by PWM. Our data demonstrated that this hypercaloric low-protein diet in rats is associated with myocardial dysfunction, altered expression of major calcium handling proteins, and increased local oxidative stress. These findings reinforce the attention needed for pediatric care, since chronic malnutrition in early life is related to increased cardiovascular risk in adulthood. Graphical Abstract.

Nutritional recovery with a soybean diet impaired the glucagon response but did not alter liver gluconeogenesis in the adult offspring of rats deprived of protein during pregnancy and lactation.

Nutritional recovery of early malnutrition with a soybean diet reduces liver glycogen stores in the fed state and produces liver insulin resistance. We investigated whether nutritional recovery on a soybean flour diet alters hepatic gluconeogenesis in the adult offspring of rats deprived of protein during pregnancy and lactation. Male rats from mothers that were fed either 17% (C) or 6% (L) protein during pregnancy and lactation were maintained on a 17% casein (CC, n = 16 and LC, n = 17), 17% soybean flour (CS, n = 10 and LS, n = 10), or 6% casein (LL, n = 10) diet after weaning. The soybean diet reduced basal serum glucose (soybean diet, 5.6 ± 0.6 mmol/L vs. casein diet, 6.2 ± 0.6 mmol/L; p < 0.05) but increased alanine aminotransferase mRNA/GAPDH (soybean diet, 0.062 ± 0.038 vs. casein diet, 0.024 ± 0.011; p < 0.01), phosphoenolpyruvate carboxykinase mRNA/GAPDH (soybean diet, 1.53 ± 0.52 vs. casein diet, 0.95 ± 0.43; p < 0.05), and glycerokinase protein content (soybean diet, 0.86 ± 0.08 vs. casein diet, 0.75 ± 0.11; p < 0.05). The serum glucose concentration (recovered groups, 5.6 ± 0.5 mmol/L vs. control groups, 6.2 ± 0.7 mmol/L; p < 0.05) and phosphoenolpyruvate carboxykinase activity (recovered groups, 2.8 ± 0.6 µU/mg vs. control groups, 3.6 ± 0.6 µU/mg; p < 0.05) were decreased in rats subjected to protein restriction in early life. The glucose area under the curve during the pyruvate tolerance test did not differ among groups, whereas glucose area under the curve after glucagon infusion was reduced by early malnutrition (recovered groups, 4210 ± 572 mg/dL·40 min vs. control groups, 4493 ± 688 mg/dL·40 min; p < 0.001) and by the soybean diet (soybean diet, 3995 ± 500 mg/dL·40 min vs. casein diet, 4686 ± 576 mg/dL·40 min; p < 0.05). Thus, the soybean diet impaired the response to glucagon but did not alter gluconeogenesis.

Reduced glucose-induced insulin secretion in low-protein-fed rats is associated with altered pancreatic islets redox status.

In the present study, we investigated the relationship between early life protein malnutrition-induced redox imbalance, and reduced glucose-stimulated insulin secretion. After weaning, male Wistar rats were submitted to a normal-protein-diet (17%-protein, NP) or to a low-protein-diet (6%-protein, LP) for 60 days. Pancreatic islets were isolated and hydrogen peroxide (H2 O2 ), oxidized (GSSG) and reduced (GSH) glutathione content, CuZn-superoxide dismutase (SOD1), glutathione peroxidase (GPx1) and catalase (CAT) gene expression, as well as enzymatic antioxidant activities were quantified. Islets that were pre-incubated with H2 O2 and/or N-acetylcysteine, were subsequently incubated with glucose for insulin secretion measurement. Protein malnutrition increased CAT mRNA content by 100%. LP group SOD1 and CAT activities were 50% increased and reduced, respectively. H2 O2 production was more than 50% increased whereas GSH/GSSG ratio was near 60% lower in LP group. Insulin secretion was, in most conditions, approximately 50% lower in LP rat islets. When islets were pre-incubated with H2 O2 (100 µM), and incubated with glucose (33 mM), LP rats showed significant decrease of insulin secretion. This effect was attenuated when LP islets were exposed to N-acetylcysteine.

DNA Methylation Signatures of Early Childhood Malnutrition Associated With Impairments in Attention and Cognition.

BACKGROUND: Early childhood malnutrition affects 113 million children worldwide, impacting health and increasing vulnerability for cognitive and behavioral disorders later in life. Molecular signatures after childhood malnutrition, including the potential for intergenerational transmission, remain unexplored. METHODS: We surveyed blood DNA methylomes (~483,000 individual CpG sites) in 168 subjects across two generations, including 50 generation 1 individuals hospitalized during the first year of life for moderate to severe protein-energy malnutrition, then followed up to 48 years in the Barbados Nutrition Study. Attention deficits and cognitive performance were evaluated with the Connors Adult Attention Rating Scale and Wechsler Abbreviated Scale of Intelligence. Expression of nutrition-sensitive genes was explored by quantitative reverse transcriptase polymerase chain reaction in rat prefrontal cortex. RESULTS: We identified 134 nutrition-sensitive, differentially methylated genomic regions, with most (87%) specific for generation 1. Multiple neuropsychiatric risk genes, including COMT, IFNG, MIR200B, SYNGAP1, and VIPR2 showed associations of specific methyl-CpGs with attention and IQ. IFNG expression was decreased in prefrontal cortex of rats showing attention deficits after developmental malnutrition. CONCLUSIONS: Early childhood malnutrition entails long-lasting epigenetic signatures associated with liability for attention and cognition, and limited potential for intergenerational transmission.

Protein-energy malnutrition contributes to increased structural chromosomal alteration frequencies in Argentinean children.

The relationship between protein-energy malnutrition and genetic damage has been studied in human beings and laboratory animals, but results are still conflicting. The aim of the present study was to assess the induction of structural chromosomal aberrations in peripheral blood lymphocytes of children with primary protein-energy malnutrition. A case-control study was performed. Samples were obtained from 25 primary malnourished infants (mean age, 22 months; range, 1-66 months). The control group consisted of 25 eutrophic children from the same population who were matched 1:1 by age and sex. Anthropometric and clinic evaluations were performed to assess nutritional condition. Before blood collection, we interviewed each individual's parent to complete a semi-structural survey specifying age, dietary habits, viral or bacterial diseases; previous exposure to diagnostic x-rays; and use of therapeutic drugs. After 48 hours, 100 cultured lymphocytes were analyzed per patient. Statistical analysis was performed using the Epi Dat 3.0 program (P < or = .05). The chromosomal aberration frequency was nearly 7 times higher in malnourished infants than in controls (14.61% vs 2.2%, respectively). This difference was statistically significant (P < .001) and may be explained by the occurrence of achromatic lesions, breaks, and telomeric associations. DNA damage could be attributed to several factors: severe deficiency of essential nutrients (ie zinc, iron, and vitamin A) required in the synthesis of DNA maintenance factors; deterioration of repair mechanisms allowing the persistence of an unusually high number of structural chromosomal aberrations; and/or the absence of specific factors needed to protect the cell against oxidative DNA damage.

Glutathione S-transferase polymorphisms may be associated with risk of oedematous severe childhood malnutrition.

It has been estimated that more than 50 % of deaths before the age of 5 years have undernutrition as an underlying cause. Severe childhood malnutrition, an extreme form of undernutrition, occurs as oedematous and non-oedematous syndromes. The reasons why only some children develop oedematous severe childhood malnutrition (OSCM) have remained elusive, but the heterogeneity of clinical appearances among children from relatively homogeneous backgrounds suggests that interindividual variation in susceptibility to OSCM may exist. We investigated variants of four glutathione S-transferase (GST) genes in a retrospective study among subjects (n 136) previously admitted to the Tropical Metabolism Research Unit, Jamaica, for the treatment of either OSCM (cases) or non-oedematous severe childhood malnutrition (controls). We found that GSTP1 Val(105) homozygotes were significantly more common among the cases (odds ratio (OR) 3.5; 95 % CI 1.1, 10.8). We also found an association of borderline significance between non-deletion GSTT1 genotypes (i.e. +/+ or +/0) and OSCM (OR 2.4; 95 % CI 1.0, 5.9). There was no significant association between OSCM and any of the other GST variants. These preliminary findings suggest that genetic variation within the GST superfamily may contribute to the risk of OSCM. Additional, larger data sets and studies of variants in other candidate genes are required in order to properly assess the true contribution, if any, of genetic variation to risk of OSCM. Such studies may improve our understanding of the causes of clinical heterogeneity in malnutrition.

Sister-chromatid exchange (SCE) and cell proliferation in lymphocytes from infected and non-infected children with severe protein calorie malnutrition (PCM).

The frequency of sister-chromatid exchanges (SCE) and the rate of cell proliferation were evaluated through differential staining of sister chromatids in mitogen-stimulated cultured lymphocytes sampled from five well-nourished children, from seven severely malnourished children infected with bacterium, and from 10 severely malnourished children following treatment for infection with antimicrobial drugs 2 weeks before blood sampling. The replication indices at 48 h of culture were higher in both groups of malnourished children than in the well-nourished children, indicating either a faster response to PHA and/or a shorter cell cycle in lymphocytes of these patients. The average frequency of SCE per mitosis was also significantly higher than in the control group. The mitotic index was similar in the three groups of children. The lack of significant difference in response between the two groups of malnourished children suggests that the effects observed at the cytogenetic level are caused by severe malnutrition per se, and not by any associated infection.

The effect of a hypoproteic diet and ethanol consumption on the yield of chromosomal damage detected in bone marrow cells of mice.

The relationship between protein malnutrition and ethanol consumption as modulating factors of the genetic response to xenobiotics was studied. BALB/c mice of both sexes were fed for three weeks after weaning either with a normal diet containing 25% protein or a hypoproteic diet containing 5% protein. Half of the animals received 20% ethanol in drinking water. Cytogenetic analysis was performed in bone marrow cells. Slides were stained for C-banding in order to assure the accurate scoring of dicentric chromosomes. Results obtained showed an increased frequency of dicentric chromosomes in mice fed with the hypoproteic diet (5.45 dicentrics per 100 cells) in contrast to mice fed with the normal diet (0.61 dicentrics per 100 cells). Ethanol consumption increased the frequency of chromosomal damage, but no differences in the effect of ethanol between mice fed with the normal diet and mice fed with the hypoproteic diet (16.33 and 16.80 dicentrics per 100 cells respectively). The enhanced frequency of dicentric chromosomes in animals fed with the hypoproteic diet might have been originated from the increase or the improper repair of chromosome breaks. The similarity in the response to ethanol consumption in animals fed either with the normal or the hypoproteic diet might have been provoked by a decrease of alcohol dehydrogenase (ADH) level in undernourished mice. The chromosomal damage due to ethanol may be lower in undernourished mice than in mice fed with the normal diet due to the reduced amount of circulating acetaldehyde able to induce chromosomal damage. The results obtained are an evidence of the role played by the diet in the modulation of the genetic response to xenobiotics.

Genetic and environmental determinants of growth of school-aged children in a rural Colombian population.

Parent-offspring correlations and heritabilities of body measurements from midparent-offspring regressions are presented for school-aged children from the village of Tenza, Colombia (N = 403 families). Parent-child correlations and midparent regressions in this subsistence farming sample, are similar in magnitude to those for well nourished, urban industrial samples, suggesting that the environmental component of variability in body size is the same regardless of the environment. Tenza children are significantly shorter and lighter than upper class Bogota children, and Tenza parents have mean heights and weights similar to those of other lower class Colombian samples. Thus, chronic undernutrition has affected the growth of parents and continues to affect the growth of the present generation. Although it has been hypothesized that heritability of growth might be reduced in samples experiencing malnutrition and its sequelae, such a reduction may only be observable where environment of parents during their development is different from that of their offspring, which is not the case here. The pattern of heritabilities with respect to different body measurements in Tenza, is similar to that seen in well nourished samples, except that measurements of breadth (biacromial, bicristal, bicondylar) have heritabilities similar in magnitude to those of linear measurements (height, sitting-height, subischial length) especially in males; and heritabilities of some measurements related to adiposity are significantly higher in daughters than in sons.