Please read the abstract in the pdf. / Thesis (PhD)--University of Pretoria, 2013. / gm2013 / Food Science / unrestricted

This study assessed aspects of targeting of the PEM scheme in Gauteng province. This food supplementation scheme targets beneficiaries including children 0-6 years, using largely anthropometric criteria. Routine provincial intervention data was analysed and related to available data cm expenditure, population and indices of socio-economic need. Only 28% were children in the critical 7-36 month age group; and coverage was very low, with no correlation between indices of need and programme implementation by area. An exit interview to a sample of caretakers of 0-6 year old children in four clinics (two Local Authority, two provincial) examined the process of identification of beneficiaries. Low attendance by children over 1 year and 40% errors in growth monitoring, more frequent among sick children, effectively reduced screening coverage among the most at-risk. Health worker misclassification resulted in an 81% exclusion error among those meeting entry criteria, while 4% of the total were wrongly enrolled. Advice and nutrition promotion to caregivers was inadequate. Recommendations include service re-organisation, community-based initiatives and better monitoring.

Little is known about the effects of protein-energy malnutrition (PEM) developing after stroke on brain recovery. The goal of this project was to develop two experimental models in the adult rat to allow evaluation of nutritional effects on post-stroke recovery: (1) a PEM model, and (2) a photothrombotic stroke model. Experiment 1 examined the hypothesis that a diet containing either 1% or 0.5% protein will produce an acute state of mild-moderate PEM in adult rats. Male, Sprague-Dawley rats (16 wk) were trained in the Montoya staircase before being randomized to diets containing 0.5% (n=8), 1% (n=8), or 12.5% protein (n=10 [CON]) for 31d. Both low protein diets increased liver lipid content (p< 0.001) and decreased food intake (p= 0.005) and body weight (p< 0.001) compared to the 12.5% protein diet. The 0.5% protein group best mimicked the stroke patient, as judged by decreased serum albumin (p= 0.018) and an acute decrease in mean (±SEM) body weight (g) by d7 (0.5%= 424±15; 1%= 428±14; CON= 477±10; p = 0.011). Increased concentrations of the positive acute phase proteins, alpha-2-macroglobulin and alpha-1-acid glycoprotein, were greatest in the 0.5% group (p< 0.001). No differences were observed in the Montoya test on d3, 15, or 30 (p= 0.26). Values on d30 were: 0.5%= 109.5±4.4% of pre-diet performance; 1%= 97.2±5.5%; CON= 98.5±10.2%. Experiment 2 tested the hypothesis that targeted laser irradiation and 30 mg/kg of rose Bengal injection will cause an infarct in the forepaw region of the cortex with accompanying functional deficits. Male adult rats trained in the Montoya staircase were randomized to ISCHEMIA (n=15) or SHAM (n=3) surgery. A cortical infarct occurred in 86% of rats, with some misplacement and variability in volume (5.7-12.8 mm3). Forepaw impairments were confirmed by decreased performance in the staircase at d3 (34.3±7.3 % of pre-stroke performance, p<0.001) and diminished use in the cylinder test (30.3±4.0% affected limb use versus 53.9±1.93% prestroke, p< 0.001). At d30, mean recovery was incomplete in the staircase (p< 0.001). These experimental models, with additional refinements, can be used to address the hypothesis that deteriorating nutritional status after a stroke interferes with brain recovery.

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Primary brain injury in stroke is followed by oxidative stress and further neural damage. Glutathione (GSH) is critical in antioxidant defense. Since cysteine is limiting in GSH synthesis, Phase 1 of this study investigated the effect of a dietary sulphur amino acid deficiency (-SAA) on neural damage in global hemispheric hypoxia-ischemia (GHHI). Rats were fed a -SAA or control diet for 6 days, and subjected to GHHI after 3 days. Histologically evaluated neural damage at 7 days post hypoxia-ischemia was greater in -SAA rats. Brain GSH concentration was decreased in -SAA rats 3 days after ischemia. A cysteine precursor, L-2-oxothiazolidine-4-carboxylic acid (OTC) administered to -SAA rats did not ameliorate neural damage. GSH is decreased by protein-energy malnutrition (PEM) in some tissues. Phase 2 investigated the effect of PEM on brain oxidative stress, neural damage and behaviour after global ischemia in adult male gerbils. In a 2x2 factorial design, gerbils were fed an adequate protein (12%; C) or low protein (2%; PEM) diet for 4 weeks, then subjected to transient ischemia (I) or sham surgery (S). After 12 hours of reperfusion, brain from half the gerbils was collected for biochemical analyses. Remaining gerbils were fed pre-surgery diets for 10 more days. To assess functional consequences of ischemia, gerbils were placed in an open field on Days 3, 7 and 10 after surgery. On Day 10, viable hippocampal CA1 neurons were counted. C-I gerbils did not habituate as readily in the open field on day 3 as C-S, but normalized by day 7. PEM-I gerbils failed to habituate by day 10, traveled greater distance than other gerbils and 7 of 12 displayed thigmotaxis, a <i>wall-hugging</i> preference for the outer perimeter of the open field. CA1 neuron loss in I was 61.5% of S, but unaffected by PEM. Four of 12 PEM-I gerbils had marked increases in hippocampal glia. Hippocampus protein thiols were reduced by PEM and by ischemia, consistent with oxidative stress. GSH concentration, glutathione reductase activity and thiobarbituric acid reactive substances were not significantly affected by PEM or ischemia. Findings from these two studies suggest well-nourished but not nutritionally-deficient rodents tolerate a mild brain insult. This is clinically relevant because many elderly stroke victims suffer from PEM at the time of ischemia, which may compromise recovery.

Our laboratory previously found that protein-energy malnutrition (PEM) existing prior to brain ischemia impaired functional outcome measured in an open field test, and one-third of animals showed a marked increase in reactive gliosis. It was hypothesized that PEM worsened stroke outcome by increasing inflammation via increased activation of the transcription factor, nuclear factor kappa B (NFκB). Mongolian gerbils (11-12 wk old) were randomly assigned to a control diet (12.5% protein) or a protein-deficient diet (2%) for 28 days. The control group on average gained 4.9g and the PEM group lost 7.4g. PEM gerbils had significantly decreased food intake (P<0.001; unpaired t-test). Animals were then subjected to global ischemia or sham surgery, resulting in four experimental groups. Global ischemia was achieved by a 5 min bilateral common carotid artery occlusion with tympanic temperature regulated at 36.5 ± 0.2C. PEM independently increased hippocampal NFκB activation by three times higher than control diet animals at 6hr after surgery (p=0.014; 2-factor ANOVA) detected by electrophoretic mobility shift assay (EMSA). There was no significant effect of ischemia on NFκB activation and there was no interaction of diet and ischemia. Serum glucose and serum cortisol were also measured since both variables can be affected by PEM and can influence stroke outcome, but there was no significant effect of diet or ischemia. Because of the increased NFκB activation observed in PEM-Sham animals, a second experiment investigated if PEM also increased NFκB activation in the absence of surgery. Gerbils of the same age were randomly assigned to either control diet or PEM for 28 days but did not receive any surgery. PEM consistently increased NFκB activation. Since PEM exists in 16% of elderly stroke patients at admission, the data suggest that PEM may worsen stroke outcome through increased activation of NFκB. Because increased NFκB activation was also observed in PEM independent of ischemia, the data also have implications for the inflammatory response of protein-energy malnourished elderly in general.

Primary brain injury in stroke is followed by oxidative stress and further neural damage. Glutathione (GSH) is critical in antioxidant defense. Since cysteine is limiting in GSH synthesis, Phase 1 of this study investigated the effect of a dietary sulphur amino acid deficiency (-SAA) on neural damage in global hemispheric hypoxia-ischemia (GHHI). Rats were fed a -SAA or control diet for 6 days, and subjected to GHHI after 3 days. Histologically evaluated neural damage at 7 days post hypoxia-ischemia was greater in -SAA rats. Brain GSH concentration was decreased in -SAA rats 3 days after ischemia. A cysteine precursor, L-2-oxothiazolidine-4-carboxylic acid (OTC) administered to -SAA rats did not ameliorate neural damage. GSH is decreased by protein-energy malnutrition (PEM) in some tissues. Phase 2 investigated the effect of PEM on brain oxidative stress, neural damage and behaviour after global ischemia in adult male gerbils. In a 2x2 factorial design, gerbils were fed an adequate protein (12%; C) or low protein (2%; PEM) diet for 4 weeks, then subjected to transient ischemia (I) or sham surgery (S). After 12 hours of reperfusion, brain from half the gerbils was collected for biochemical analyses. Remaining gerbils were fed pre-surgery diets for 10 more days. To assess functional consequences of ischemia, gerbils were placed in an open field on Days 3, 7 and 10 after surgery. On Day 10, viable hippocampal CA1 neurons were counted. C-I gerbils did not habituate as readily in the open field on day 3 as C-S, but normalized by day 7. PEM-I gerbils failed to habituate by day 10, traveled greater distance than other gerbils and 7 of 12 displayed thigmotaxis, a <i>wall-hugging</i> preference for the outer perimeter of the open field. CA1 neuron loss in I was 61.5% of S, but unaffected by PEM. Four of 12 PEM-I gerbils had marked increases in hippocampal glia. Hippocampus protein thiols were reduced by PEM and by ischemia, consistent with oxidative stress. GSH concentration, glutathione reductase activity and thiobarbituric acid reactive substances were not significantly affected by PEM or ischemia. Findings from these two studies suggest well-nourished but not nutritionally-deficient rodents tolerate a mild brain insult. This is clinically relevant because many elderly stroke victims suffer from PEM at the time of ischemia, which may compromise recovery.

Our laboratory previously found that protein-energy malnutrition (PEM) existing prior to brain ischemia impaired functional outcome measured in an open field test, and one-third of animals showed a marked increase in reactive gliosis. It was hypothesized that PEM worsened stroke outcome by increasing inflammation via increased activation of the transcription factor, nuclear factor kappa B (NFκB). Mongolian gerbils (11-12 wk old) were randomly assigned to a control diet (12.5% protein) or a protein-deficient diet (2%) for 28 days. The control group on average gained 4.9g and the PEM group lost 7.4g. PEM gerbils had significantly decreased food intake (P<0.001; unpaired t-test). Animals were then subjected to global ischemia or sham surgery, resulting in four experimental groups. Global ischemia was achieved by a 5 min bilateral common carotid artery occlusion with tympanic temperature regulated at 36.5 ± 0.2C. PEM independently increased hippocampal NFκB activation by three times higher than control diet animals at 6hr after surgery (p=0.014; 2-factor ANOVA) detected by electrophoretic mobility shift assay (EMSA). There was no significant effect of ischemia on NFκB activation and there was no interaction of diet and ischemia. Serum glucose and serum cortisol were also measured since both variables can be affected by PEM and can influence stroke outcome, but there was no significant effect of diet or ischemia. Because of the increased NFκB activation observed in PEM-Sham animals, a second experiment investigated if PEM also increased NFκB activation in the absence of surgery. Gerbils of the same age were randomly assigned to either control diet or PEM for 28 days but did not receive any surgery. PEM consistently increased NFκB activation. Since PEM exists in 16% of elderly stroke patients at admission, the data suggest that PEM may worsen stroke outcome through increased activation of NFκB. Because increased NFκB activation was also observed in PEM independent of ischemia, the data also have implications for the inflammatory response of protein-energy malnourished elderly in general.

Made available in DSpace on 2014-06-11T19:30:57Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-03-08Bitstream added on 2014-06-13T20:21:28Z : No. of bitstreams: 1 000739144.pdf: 33924077 bytes, checksum: 26a331637fe3fc03cecbf7d8dfd983e6 (MD5) / A programação fetal por restrição proteica materna durante a gestação (PFG) torna o feto exposto a altas concentrações de hormônios maternos, predispõe o indivíduo a desenvolver síndrome metabólica, diminui a taxa de fertilidade e altera o tempo de instalação da puberdade. No entanto, pouca atenção tem sido destinada ao estudo dos efeitos da PFG sobre o desenvolvimento do sistema reprodutor masculino, particularmente a próstata que além de sua importância para a fertilidade apresenta alta incidência de doenças na idade adulta e senil. Assim, este projeto teve por objetivo investigar os impactos da PFG sobre o desenvolvimento da próstata e se a PFG promove o imprinting estrogênico na próstata. Para isso, ratos Wistar nascidos de ratas alimentadas com dieta padrão (grupo NP, dieta AIN93G contendo 17% de proteína) ou dieta com restrição proteica (grupo RP, dieta AIN93G modificada contendo 6% de proteína) foram divididos em três experimentos. Experimento 1: os lobos prostáticos ventral (PV) e dorsolateral (PDL) foram coletados de animais NP e RP sacrificados com 30, 120 e 360 dias para a padronização do modelo experimental e a descrição dos efeitos da PFG sobre o desenvolvimento, crescimento, maturação e envelhecimento da próstata. Experimento 2: as PV e PDL de animais NP e RP (17 semanas de idade) expostos durante 17 semanas aos hormônios testosterona e estradiol (implante subcutâneo com liberação diária de 0,08 mg de 17b-estradiol e 0,8 mg de propionato de testosterona) foram coletadas no intuito de avaliar se a PFG desencadeou imprinting hormonal e tornou a próstata mais susceptível a afecções na idade adulta. Experimento 3: animais NP e RP submetidos a castração cirúrgica ou castração química (0,08 mg/kg/dia de 17b-estradiol) ou suplementação androgênica (4 mg/kg/dia de cipionato de testosterona) tiveram a PV coletada para investigar se o imprinting hormonal desencadeado... / The fetal programming by maternal protein malnutrition (MPM) makes the fetus exposed to high concentrations of maternal hormones, predisposes individuals to develop metabolic syndrome, reduces the fertility rate and changes the time of onset of puberty. However, little attention has been devoted to studying the effects of MPM on the development of the male reproductive system, particularly the prostate that besides its importance for fertility, it has high incidence of disease in adulthood and senile. In this sence, the study aimed to investigate the impacts of MPM on development of the prostate and if the MPM is able to promote the estrogen imprinting in the prostate. For this, Wistar rats born from rats fed with standard diet (NP group, AIN93G diet = 17% protein) or a restricted protein diet (RP group, AIN93G modified diet = 6% protein) were divided into three experiments. Experiment 1: ventral prostate (VP) and dorsolateral (DLP) were collected from NP and RP animals sacrificed with 30, 120 and 360 days for the standardization of the experimental model and description of the PFG effects on prostate development, growth and maturation aging. Experiment 2: VP and the DLP from NP and RP animals (17 weeks-old) that were exposed for 17 weeks to hormones testosterone plus estradiol (subcutaneous implant of 0.08 mg of 17b-estradiol and 0.8 mg propionate testosterone day-release) were collected in order to assess whether the MPM triggered hormonal imprinting and become more susceptible to prostate disorders in adulthood. Experiment 3: VP from NP and RP animals underwent to surgical castration or chemical castration (0.08 mg/kg/day 17b-estradiol) or androgen supplementation (4 mg/kg/day of testosterone cypionate) were collected to investigate whether hormonal imprinting triggered by PFG changed the pattern of glandular response to these manipulations. Once dissected, the prostates were processed for ...

The overarching aim of the thesis research was to investigate mechanisms altered by protein-energy malnutrition (PEM), a common stroke co-morbidity factor that could affect the extent of brain damage and recovery following stroke. To model stroke, the rat 2-vessel occlusion model of global brain ischemia was employed. To characterize the effects of PEM, three states of malnutrition were assessed: PEM co-existing with brain ischemia (Study 1), effects of PEM independent of brain ischemia (Study 2), and PEM developing after brain ischemia (Study 3). The first hypothesis tested was co-existing PEM triggers an exacerbated glial response to global brain ischemia. The failure to achieve a consistent model of global ischemia prevented us from drawing conclusions on whether co-existing PEM exacerbates reactive gliosis. Nonetheless, this study demonstrated that mean temperature and temperature fluctuation are increased within the first 24hr of exposure to a low protein diet. The second hypothesis tested was PEM causes sustained changes in core temperature that are associated with an inflammatory response. Exposure to a low protein diet caused an immediate small and transient increase in mean temperature and a larger sustained increase in temperature amplitude. As malnutrition evolved, mean temperature declined. PEM stimulated an acute-phase response, characterized by an increase in the positive acute-phase protein, alpha-2-macroglobulin (A2M), and a decrease in the negative acute-phase protein, albumin. This response appeared to be aberrant, since the positive acute-phase protein, alpha-1-acid glycoprotein (AGP), was decreased with PEM. The final hypothesis tested was PEM developing after global brain ischemia exacerbates systemic and hippocampal inflammation, which is associated with diminished neuroplasticity. The effects of PEM on the acute-phase response are persistent following brain ischemia, as demonstrated by decreased serum albumin and increased serum A2M. A decrease in the positive acute-phase protein, haptoglobin, strengthened the evidence that PEM triggers an atypical reaction. The strong glial response elicited by global ischemia was unaltered by PEM. However, PEM influenced hippocampal neuroplasticity mechanisms, as GAP-43 and synaptophysin were significantly lower at d21. In summary, it has been demonstrated that PEM affects core temperature, the systemic acute-phase reaction and the neuroplasticity response to global brain ischemia.