Characterizing the metabolic phenotype of intestinal villus blunting in Zambian children with severe acute malnutrition and persistent diarrhea

Background

Environmental enteric dysfunction (EED) is widespread throughout the tropics and in children is associated with stunting and other adverse health outcomes. One of the hallmarks of EED is villus damage. In children with severe acute malnutrition (SAM) the severity of enteropathy is greater and short term mortality is high, but the metabolic consequences of enteropathy are unknown. Here, we characterize the urinary metabolic alterations associated with villus health, classic enteropathy biomarkers and anthropometric measurements in severely malnourished children in Zambia.

Methods/Principal findings

We analysed 20 hospitalised children with acute malnutrition aged 6 to 23 months in Zambia. Small intestinal biopsies were assessed histologically (n = 15), anthropometric and gut function measurements were collected and the metabolic phenotypes were characterized by ¹H nuclear magnetic resonance (NMR) spectroscopy.

Endoscopy could not be performed on community controls children. Growth parameters were inversely correlated with enteropathy biomarkers (p = 0.011) and parameters of villus health were inversely correlated with translocation and permeability biomarkers (p = 0.000 and p = 0.015). Shorter villus height was associated with reduced abundance of metabolites related to gut microbial metabolism, energy and muscle metabolism (p = 0.034). Villus blunting was also related to increased sucrose excretion (p = 0.013).

Conclusions/Significance

Intestinal villus blunting is associated with several metabolic perturbations in hospitalized children with severe undernutrition. Such alterations include altered muscle metabolism, reinforcing the link between EED and growth faltering, and a disruption in the biochemical exchange between the gut microbiota and host. These findings extend our understanding on the downstream consequences of villus blunting and provide novel non-invasive biomarkers of enteropathy dysfunction. The major limitations of this study are the lack of comparative control group and gut microbiota characterization.

Effects of neonatal programming on hypothalamic mechanisms controlling energy balance

The prevalence of overweight and obesity in most developed countries has markedly increased during the last decades. In addition to genetic, hormonal, and metabolic influences, environmental factors like fetal and neonatal nutrition play key roles in the development of obesity. Interestingly, overweight during critical developmental periods of fetal and/or neonatal life has been demonstrated to increase the risk of obesity throughout juvenile life into adulthood. In spite of this evidence, the specific mechanisms underlying this fetal/neonatal programming are not perfectly understood. However, it is clear that circulating hormones such as insulin and leptin play a critical role in the development and programming of hypothalamic circuits regulating energy balance. Here, we review what is currently known about the impact of perinatal malnutrition on the mechanisms regulating body weight homeostasis. Understanding these molecular mechanisms may provide new targets for the treatment of obesity.

Validation of mid upper arm circumference cut offs to diagnose severe wasting in Indian children

This study aimed to assess the sensitivity, specificity, predictive values, and Youden index for mid-upper-arm-circumference cut-off of 115 mm to diagnose severe wasting (as defined by the revised WHO standards) in 346 underweight children aged 6 months to 5 years from an outpatient setting. A cut-off of 115 mm had a better performance (sensitivity 43.2%, specificity 90%, Youden index 0.32) than 110 mm (sensitivity 26.4%, specificity 95.9%, Youden index 0.22) in diagnosing severe wasting. The best performance in terms of a balance between sensitivity and specificity was that of 120 mm (sensitivity 74.4%, specificity 77.8%, Youden index 0.52).

Undernutrition & risk of infections in preschool children

BACKGROUND & OBJECTIVE

It is well documented that in preschool children undernutrition is associated with immune depression and increased risk of infections; infections aggravate undernutrition. Underweight is the most widely used indicator for assessment of undernutrition for investigating undernutrition and infection interactions. In India, nearly half the children are stunted and underweight; but majority of children have appropriate weight for their height and less than a fifth are wasted. The present study was undertaken to explore which of the five anthropometric indices for assessment of undernutrition (weight for age, height for age, wasting, BMI for age, and wasting and stunting with low BMI) is associated with more consistent and higher risk of morbidity due to infection in preschool children.

METHODS

The National Family Health Survey-3 (NFHS-3) database provided the following information in 56,438 preschool children: age, sex, weight, height, infant and young child feeding practices and morbidity due to infections in the last fortnight. Relative risk (RR) of morbidity due to infections was computed in infants and children with stunting, underweight, low BMI for age, wasting and stunting with low BMI (< mean-2SD of WHO 2006 standards).

RESULTS

Comparison of the RR for infections in undernourished children showed that the relative risk of morbidity due to infections was higher and more consistently seen in children with low BMI and wasting as compared to stunting or underweight. The small group of children who had stunting with wasting had the highest relative risk of morbidity due to infection.

INTERPRETATION & CONCLUSION

In Indian preschool children, RR for infection was more consistently associated with BMI for age and wasting as compared to weight for age and height for age. Low BMI for age and wasting indicate current energy deficit; early detection and correction of the current energy deficit might reduce the risk of infection and also enable the child to continue in his/her growth trajectory for weight and height.

Clinical features of selenium deficiency in infants receiving long-term nutritional support

OBJECTIVE

Selenium deficiency is a known complication in patients requiring long-term nutritional support; however, the clinical features of selenium deficiency in infants have not been completely described. We describe the clinical features of selenium deficiency in infants.

METHODS

Six infants with selenium deficiency were studied retrospectively, with a focus on the period of nutritional support, the clinical symptoms, and the chronologic changes in serum selenium concentrations before and after the administration of selenite.

RESULTS

The onset of selenium deficiency in five patients occurred at <6 mo of age; selenium deficiency occurred in one patient 14 mo after birth. One patient received parenteral nutrition for 15 mo after birth; the other five patients primarily received an elemental diet for 2-6 mo. In all patients, growth retardation and alopecia with pseudoalbinism were the characteristic symptoms of selenium deficiency. At the time of diagnosis, the serum selenium level in four patients was <2.0 microg/dL and serum selenium levels in two patients were 3.2 and 3.3 microg/dL, respectively. The resolution of hair symptoms corresponded to the level of serum selenium after 1-2 mo and a rapid improvement in growth occurred in all patients after the administration of selenite.

CONCLUSION

The early clinical symptoms of selenium deficiency in infants include growth retardation and alopecia with pseudoalbinism, which are reversible if the patients are treated with adequate amounts of selenite. Clinicians who manage infants receiving long-term nutritional support, including an elemental diet, should be aware of the symptoms associated with selenium deficiency.

Neonatal enteropathies: defining the causes of protracted diarrhea of infancy

The underlying causes of chronic diarrhea beginning early in life are increasingly well defined. Infectious and post-infectious enteropathies and food sensitive/allergic enteropathy account for the majority of cases. Recent attention has focused on characterizing defined entities, which cause protracted diarrhea in infants and young children. Disorders of intestinal ion transport usually present at birth following a pregnancy complicated by polyhydramnios. Intestinal mucosal biopsies show normal architect with intact villus-crypt axis. Neonatal enteropathies, by contrast, are characterized by blunting of the villi. These include microvillus inclusion disease, tufting enteropathy, autoimmune enteropathy and IPEX syndrome - and it is these conditions that are the subject of the current review.

Development of impaired cell-mediated immunity in mild and moderate malnutrition

The development of moderate malnutrition and cell-mediated immune function was studied in 71 Colombian infants from birth through 2 yr of age. Based upon weight-for-age criteria 31 remained normal, 33 were classified as grade I, and seven were grade II malnourished at the end of their 2nd yr of life. Delayed hypersensitivity reactions to purified protein derivative were significantly reduced in all malnourished children 8 wk after Bacille Calmette-Guerin vaccination at birth, and also at 2 yr in the Grade II group. Nearly half of the latter group could not be sensitized to dinitrochlorobenzene at 2 yr of age. A 50% reduction in the blastogenic response of peripheral blood lymphocytes to phytohemagglutinin in vitro was detected in grade II children. Both mildly and moderately malnourished infants exhibited a significant reduction in tonsil size at 2 yr of age. These results indicate that a majority of newborns in this poor, urban setting will develop measurable malnutrition associated with impaired cell-mediated immune function before their 2nd birthday.

Growth of muscle fibres during recovery from severe malnutrition in Jamaican infants

1. The growth of muscle fibres was analysed by light microscopy in biopsies from subjects when malnourished, during nutritional rehabilitation, and after clinical recovery. 2. Muscle fibres from malnourished subjects were extremely atrophic (cross-sectional area, 110 micrometers2). The fibres doubled in size during the early period of rehabilitation. Growth of muscle fibres during later periods of rehabilitation occurred at a slower rate. 3. The absolute rates of change in fibre sizes differed considerably between subjects, but the rates of change relative to the rate of gain of total body-weight (expressed as % recovery or % expected weight-for height (Nelson, 1975)) were similar between subjects after the initial growth spurt. The pattern of recovery appeared to differ between older and younger subjects. 4. Fibre sizes correlated with body-weight but not with age in the malnourished subjects. A significant correlation between fibre areas and either weight or age was observed during rehabilitation and after clinical recovery. 5. Fibre sizes of clinically-recovered subjects (mean age, 13.8 months; weight, 8.7 kg) were only approximately 60% of that for a well-nourished 6-month-old control subject (6.4 kg). These results suggest that a longer period of time is required for fibres to reach their expected size. Therefore, when the child has regained body-weight to that of a normal child of the same height, his muscles have not yet recovered and his body composition is abnormal.

Familial enteropathy: a syndrome of protracted diarrhea from birth, failure to thrive, and hypoplastic villus atrophy

We have studied 5 infants with persistent severe diarrhea from birth and marked abnormalities of absorption associated with failure to thrive leading to death in 4 infants. Three had siblings who died and a sibling of a 4th is ill at present, all with a similar illness; 2 were the products of consanguinous marriages. Exhaustive investigation failed to identify a recognized disease entity in any patient. Steatorrhea, sugar malabsorption, dehydration, and acidosis were severe in all patients, whatever the diet fed. Total parenteral nutrition was used, but excessive stool water and electrolyte losses persisted even when nothing was fed by mouth. There was no evidence of a hematological or consistent immunological defect in any infant and no abnormalities of intestinal hormones were noted. In the duodenal mucosa of all infants we saw similar abnormalities characterized by villus atrophy, crypt hypoplasia without an increase in mitoses or inflammatory cell infiltrate in the lamina propria and in villus enterocytes absence of a brush border, increase in lysosome-like inclusions, and autophagocytosis. In 3 infants studied by marker perfusion of the proximal jejunum we found abnormal glucose absorption and a blunted response of Na+ absorption to actively transported nonelectrolytes; in 2 there was net secretion of Na+ and H2O in the basal state. Our patients evidently suffered from a congenital enteropathy which caused profound defects in their capacity to assimilate nutrients. The similar structural lesion seen in the small intestinal epithelium of all of our cases undoubtedly contributed to their compromised intestinal function, but the pathogenesis of this disorder, if indeed it is a single disease, remains obscure.

Fine structure of the small intestinal mucosa in infantile marasmic malnutrition

The jejunal mucosa was studied in infantile marasmic malnutrition in the early phase after treatment was begun and before the onset of significant weight gain. In 7 infants light microscopy before recovery showed that the mucosa was normal or mildly abnormal in 4, and moderately abnormal in 3 cases. The electron microscope disclosed abnormalities of the brush border, large autophagosomes and residual bodies, and the deposition of collagen, filaments, and a dense, finely granular material below the basal lamella. Three of the infants were studied again during recovery. Although the histology remained unchanged, electron microscopy revealed improvement of the brush border, disappearance of the autophagosomes, and smaller and fewer residual bodies. The dense material below the basal lamella was absent whereas the fibrillar components remained. It is postulated that the fine structural lesions observed may be due to the derangements in cell metabolism caused by the severe, prolonged restriction of protein and caloric intake.

[Experimental malnutrition: biochemical and anatomic-pathological results of feeding a protein-deficient diet to young albino rats]

Na tentativa de reproduzir experimentalmente os achados morfológicos e eletroforéticos (proteínas no soro) observados na desnutrição infantil, dois grupos de experiências foram realizados em ratos albinos jovens, submetendo-os a uma dieta pobre em proteínas (2%) por períodos de 41 a 88 dias. O modelo experimental reproduz em linhas gerais os principais danos estruturais vistos na patologia humana, ficando num meio termo entre kwashiorkor e marasmo. Alterações atróficas tegumentares foram assinaladas como achado tardio. O achado mais conspícuo foi metamorfose gordurosa hepática do tipo perilobular. A regeneração hepatocelular foi abortiva, aparecendo nos estágios finais das experiências ao lado dos fenômenos regressivos. Foi possível estabelecer seqüência lesional nas alterações estruturais do pâncreas, desde mofificações da quantidade de grânulos de zimogênio nos estágios iniciais até a atrofia acinosa acentuada, subvertendo a arquitetura do órgão, nos estágios finais. As alterações intestinais culminaram com o quadro de atrofia, não comparável em intensidade com a patologia humana, correspondem à diminuição da altura do epitélio mucoso, hipocelularidade da lâmina própria, criptas pequenas, pobreza em mitoses, que encurtam as vilosidades, assemelhando-se ao padrão mucoso dos chamados animais "germ-free". Além disso, os autores chamam a atenção para a intensa dimuição das célular muco-secretoras ao nível do epitélio do intestino delgado e grosso. No modelo surpreende-se também uma depleção linfo-histiocitária, representada por atrofia das placas de Peyer, diminuição das célular de Kupffer, atrofia do timo e depleção linfóide ganglionar e esplênica. O estudo bioquímico do soro revelou baixa das proteínas totais e do colesterol. A eletroforese de proteínas demonstrou acentuada baixa da fração albumina, com inversão A/G. Entre as globulinas, as frações alfa1 e alfa2 estão aumentadas no grupo desenutrido. Estes achados podem ser atribuídos à carência protéica, porquanto os controles utilizados, mesmo aqueles com restrição calórica, não apresentaram alterações histológicas ou hipoalouminemia.

Hardness of finger nails in well-nourished and malnourished populations

1. The Knoop test of hardness applied to samples of finger nails from 334 healthy and 147 malnourished individuals showed statistically significant differences in the mean hardness of the nails of the two groups.

2. The hardest nails were those of Filipino infants and children suffering from protein-energy deficiency. The softest nails were those of children in Guatemala recovering from protein-energy deficiency. Ranking of hardness appeared to be related to the severity and duration of protein-energy depletion.

3. In children up to 12 years of age, hardness did not appear to be influenced by the age, sex, and racial origins of individuals or the environmental conditions to which nail specimens were exposed.

4. Further studies are required to correlate hardness with clinical, biochemical and anthropometric measurements of nutritional status during protein-energy deprivation and during recovery. The causes of the differences in hardness need to be explored.

A paediatric tube and capsule for suction biopsy of the small intestinal mucosa designed for direct nasogastric intubation

The use of a modified paediatric tube and capsule for suction biopsy of the mucosa of the small intestine is discussed. The tube is small in diameter and can be introduced through the nose without local trauma and with minimal discomfort. The intubation technique was followed in 72 instances to obtain suction biopsies from the proximal mucosa of the small intestine in protein-calorie malnourished children, and the results obtained with this instrument are also presented.

The thyroid in malnutrition

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