Mécanismes de la dénutrition chez l'enfant et l'adolescent

Malnutrition in child and adolescent is observed in various situations where there is an imbalance between the food intakes and caloric and proteic needs. Child is particularly vulnerable because its reserves are weak and its high caloric and proteic needs because of its growth. Various mechanisms leading to malnutrition were brought back and correspond to distinct clinical entities. The situations of malnutrition by exclusive mechanism of intake deficiency meet primarily in third world where they can take the form of starvation, extreme adaptive situation with prolonged fast. During situations known as of aggression like severe sepsis, polytraumatism, extended burn, surgery, malnutrition can settle quickly. Mechanism brought back in situation of acute aggression is defined classically like related to hypermetabolism with hypercatabolism. Kwashiorkor, another type of caloric and proteic malnutrition concerning child in third world, cannot be regarded as a simple caloric and proteic deficiency. It currently seems that a deficiency at the same time in macronutriments and micronutriments plays a part in genesis of this pathology. The glutathion seems in particular, to play a fundamental part in the kwashiorkor's pathophysiology. The most documented hypothesis relates imbalance between production of free radicals and mechanisms of defence. Mechanisms of repair would be insufficient, and persistence of membrane deteriorations would cause anomalies observed in kwashiorkor like oedema, hepatic overload, neurological disorders and diarrhoea.     

État nutritionnel des patients avec maladies du foie : épidémiologie et pronostic

Malnutrition is generally defined as protein-energy malnutrition (PEM) in patients with chronic liver disease, because the depletion of muscle mass and body fat is associated with protein depletion. Deficiencies of vitamins and minerals often coexist. PEM represents a common complication of advanced liver disease, both of alcoholic and nonalcoholic etiology. It is related to the severity of the liver disease more than to its etiology.Malnutrition negatively affects liver function, complications of the liver disease, and survival. Malnourished patients have an increased surgical risk and decreased survival after liver transplantation. The assessment of nutritional status in patients with chronic liver disease may be helpful in providing better prognostic information and more precise targeting of potential nutrition intervention.     

Rôle du foie dans le métabolisme des nutriments en nutrition artificielle

The liver is a prominent organ in nutritional homeostasis. Due to unique metabolic properties, it plays a main role in the metabolism of the three macronutrients ‘as well as the micronutrients’ (vitamins and minerals) storage. Although it represents only 2.5% of the body mass, it consumes 20% of total resting energy expenditure and a similar percentage of the amino acid mixture absorbed via the gut during and after a meal. Due to a peculiar vascularization (portal vein, the entire gastrointestinal venous flux is directed towards the liver with all hydrosoluble nutrients, only water-unsoluble lipids being excluded from this obligatory ‘first-pass mechanism’). Since it is the location for glycogen storage, VLDL synthesis and ketogenesis, the liver is crucial in the fed-to-fasted metabolic alternation. While fat is not physiologically stored in the liver, it is a very important organ in lipid metabolism. Except immunoglobulins, all plasma proteins are synthetised by the liver together with the constitutive proteins, explaining that it is a very powerful organ for protein synthesis. Finally, due to a very active amino acid metabolism, the liver can reshape the amino acid-mixture coming from the gut in the absorptive state. Such a phenomenon has a major implication in the nutritional physiology of amino acid metabolism according to the route: enteral or parenteral. Indeed, in the latter case the remodelling by the liver does not occurs.     

Stratégies de dépistage de la dénutrition chez l''enfant hospitalisé

Metabolic stress modifies homeostasis, therefore nutrient's metabolism and nutritional needs. Stress is a risk factor of malnutrition, which increases morbidity and short-term mortality, and, in the child, can threaten long-term growth. Nutritional assessment is difficult in critically ill children. Nutritional support must be undertaken early as possible, especially in malnourished children and with severe agression. Enteral nutrition must be privileged. Parenteral nutrition is indicated when enteral nutrition is impossible, badly supported or insufficient to satisfy needs. Monitoring must be rigorous because aggression increases the risk of metabolic complications.     

Éléments traces, stress oxydant et hépatopathies alcooliques

Marked disorders in trace-element homeostasis occurred following various experimental conditions of ethanol administration. A decrease in zinc, copper and selenium, and an increase in non-heme iron are often observed at the hepatic level. Some of these alterations may contribute to collagen accumulation and to the decrease in the major enzymatic antioxidants such as superoxide dismutase (Cu, Zn-SOD) and glutathion peroxidase (Se-GPx). The decrease in the antioxidant defense associated with the increase in the low molecular weight non-heme iron complexes or redox active iron, a pro-oxidant factor, may play a prominent role in the occurrence of oxidative stress, which leads to enhanced lipid peroxidation. The severity of inflammatory and fibrotic disorders, which has been reproduced in rats by long-term ethanol administration associated with a high fat diet, is correlated to the intensity of oxidative stress. Clinical studies report alterations in trace elements and in some parameters of oxidative stress in patients suffering from alcohol-dependent liver disease. Supplementation with selenium and/or zinc may be considered in the prevention of the progressive alcoholic liver injury.     

Comparaison du mode entéral et parentéral de nutrition artificielle en pneumologie

Malnutrition is a common complication of chronic or acute respiratory insufficiencies. It can justify resorting to nutritional support. Very few studies have compared enteral and parenteral modes of artificial nutrition in respiratory diseases. However several theoretical arguments plead on behalf of the preferential use of enteral nutrition, most particularly in patients with chronic pulmonary disease in stable condition or in acute exacerbation, in adult respiratory distress syndrome and in cystic fibrosis patients.     

Outils et procédures de dépistage de la dénutrition et de son risque en milieu hospitalierTools and procedures for screening for malnutrition and its associated in risks in hospital

Malnutrition affects on average 20–50% of hospital inpatients and its negative repercussions in terms of morbi-mortality have been fully documented. Although this state of affairs is well known, there is little screening for malnutrition in hospitals. There is no single parameter indicating malnutrition, which instead has to be diagnosed based on anthropometric and biological data, and by multi-factorial indices of nutritional risk. Screening adapted to each of the four main classes of hospital care, acute medicine and surgery, intensive care, geriatrics and paediatrics needs to be systematically performed for every inpatient. To make malnutrition screening a natural part of the practice of care, we need to design training courses, which highlight the benefits in terms of length of stay, morbi-mortality and cost.     

Conséquences de la dénutrition chez l'enfant et l'adolescent. Mortalité, morbidité, conséquences médicoéconomiques

In the developed countries, the sick children are at risk of protein-energy malnutrition (PEM). Marasmus is the most common form of severe PEM in such children. Its major characteristics are low muscle and fat masses with the presence of marked facial, axillary and inguinal skinfolds. Furthermore the marastic children are irritable and depressed. When the PEM is moderate, which is more frequent, the affected children present a failure to thrive. Severe and moderate PEM have multiple functional consequences on different systems and organs with an impact on mortality, morbidity and costs. In this paper, the functional consequences on the immune system, digestive tract, liver, lung, heart, kidney, skin, bone and brain are passed in review. To end, some comments are done about the particularities of PEM in mental anorexia and obesity.     

Manifestations digestives et nutritionnelles des déficits immunitaires congénitaux et acquis chez l'enfant

The gastrointestinal and nutritional impact of congenital immunodeficiencies is varied and non-specific (serious refractory diarrhea, exsudative enteropathy, enterocolitis and chronic infections by Cryptosporidium, Giardia, rotavirus, Candida, etc.). Ulcerative colitis and autoimmune diseases are less frequent. Available therapeutic tools (immunoglobulins, implantable venous accesses and BMT) are reasonably effective. AIDS in children can be either rapidly or slowly progressive, and is usually due to maternofetal transmission. Gastrointestinal lesions are non-specific (candidiasis, chronic malabsorptive diarrhea, hepatitis, cryptosporidiosis, CMV, giardiasis, herpes) and cause overall malnutrition. Early nutritional support is indicated, but the modalities and results remain to be determined.     

Vieillissement humain : évolution démographique et implications médicales

French population ageing is constant since 1960. Even if elderly people quality of life keeps on improvement, population ageing leads to increasing consumption of care. Dementia, dependencies, are more frequent, and lead to many diseases, especially through malnutrition. This phenomenon have to be anticipate with global and coordinated agreement of sanitary, medical and psycho-social organization.     

Nutrition, démences vasculaires et maladie d’Alzheimer

Approximately 770,000 persons in France suffer from dementia. Alzheimer’s disease is the most frequent cause of dementia, followed by the vascular and mixed forms of dementia. In mixed dementia, the vascular lesions contribute to the severity of the cognitive impairment linked to neurodegenerative lesions. In fact, although the prevalence of cerebrovascular disease and Alzheimer’s disease are both high, some data suggest that their association is not fortuitous. Some vascular risk factors, that also represent risk factors for the development of dementia, are liable to be modified, and especially by nutrition. The question is to what extent nutritional factors may de implicated in the risk of developing dementia, and thus to estimate the possibility of modulating this risk by environmental measures. Cognitively impaired patients lose weight and present many nutritional deficiencies, but transversal studies do not allow to establish a causal link between nutrition and the risk of developing dementia. Longitudinal and cohort studies show an association between diabetes, hyperhomocysteinemia, hypercholesterolemia, low intake in n-3 fatty acids and oxidative stress and the risk of dementia. These nutritional factors contribute to the process of atherosclerosis, but also seem implicated in the physiopathology of neurodegenerative lesions by complex mechanisms. On the whole, few interventional studies have been conducted. Only these studies will help propose specific nutritional recommendations for the prevention of the risk of dementia, and/or to develop a new therapeutic approach. Meanwhile, the priority seems to prevent vascular risk factors, in accordance with the objectives of the Programme National Nutrition et Santé.     

Aspects métaboliques de la dénutrition au cours de la maladie VIH

The Wasting Syndrome (WS) is one of the major aspects of the acquired immunodeficiency syndrome (AIDS). Fat free mass, the amount of functionnal protoplasm in non adipose tissue is an independent predictor of death in AIDS patients.The deficit of the energy balance could be the result of decreased caloric intake and/or increased energy expenditure. Elevated Resting Energy Expenditure (REE) has been reported in the early stage of the HIV infection. Patients with AIDS who had active secondary infection had a striking average weight loss resulting of the combination of anorexia and dramatic elevated REE. The role of cytokines in the WS was proposed in reason of the in vitro and in vivo metabolic disturbances induced by these cytokines. The difference studies suggest that synergistic interactions between cytokines may be necessary for developping the WS.     

Place de l'impédancemétrie dans le dépistage de la dénutrition à l'hôpitalBio-impedance analysis: Screening of denutrition in hospitalized patients

The prevalence of malnutrition is high in patients and tends to worsen during the hospital stay. In the absence of one reliable method to evaluate patients, the assessment of nutritional status is based on a global approach. Body composition measurement by bio-impedance analysis (BIA) is one of these approaches. Body composition measurements can detect malnutrition or abnormal hydration. Fat free mass, fat mass, and total body water are the main body compartments that are evaluated. Determination of abnormal body composition can then guide nutritional support. The reliability of BIA depends on the equation used to predict body composition and the parameters included in the formula (weight, height, sex, age, race, etc.). These parameters allow to minimize measurement errors. Thus, formula developed for specific populations allow to evaluate the nutritional status with reasonable error rates. BIA has been found to be inaccurate with abnormal distribution of body compartments (ascites, dialysis, lypodystrophy, etc.) or extreme weights (cachexia, obesity). Multi-frequency or segmental BIA was developed to overcome hydration abnormalities and variations in body geometry. However, these techniques require further validation. The BIA seems to have some limitations. This review aims to assess the reliability of BIA to detect protein-calorie malnutrition at hospital admission or during nutritional follow-up of patients.     

Définition et évolution du statut nutritionnel au cours d'une greffe osseuse allogénique (15 malades): Rôle de la nutrition parentérale et de l'apport azoté

Our work concerned 15 patients (9 males, 6 females) with a mean age of 29.5 years, having a hematologic malignant disease and undergoing allogenic bone marrow transplantation.We studied :

1. The metabolic disorders induced by the conditioning regimen (chemotherapy and total body irradiation) pregraft accompanying cytolysis (day −7, −5, −2).

2. The corrective effect of a total parenteral nutrition introduced 2 days before the transplantation and pursued during 30 days post-graft (day −2 to day 30).

3. The interest of a high calorie intake (BEE × 2) and, after randomisation, of a variable nitrogen intake (24% of the total calorie intake for group A [8 patients] and 14% for group B [7 patients]). The patient characteristics of these two groups were closely comparable. Urinary parameters were studied daily (3-methylhistidine, cratinine, nitrogen) and blood parameters weekly (transferrin, pre-albumin, albumin, retinol binding protein).

We observed globally :

-- An excellent result of the nutritional support without significant weight loss;

-- protein catabolism stopped with a recovery of synthesis of RBP after day 7 and pre-albumin from day 7;

-- a decrease in muscle catabolism.

The randomized study showed :

-- a significant difference in nitrogen excretion between group A and group B;

-- earlier and better protein synthesis recovery in group A, particularly with regard to RBP and pre-albumin.

In conclusion, we recommend for the patients undergoing bone marrow transplantation :

-- nutritional support should be introduced before the conditioning regimen;

-- a high calorie intake (BEE × 2) with a nitrogen intake between 14% and 24% of the total calorie intake;

-- cyclic parenteral nutrition should be pursued during the second and third month post-graft.

Étude de la cytotoxicitéin vitro de dérivés du carbazole III. 3-Amino et 3-nitro-1,4-diméthyl-9H-carbazoles diversement substitués en position 6

La synthèse d'une série de 3-nitro et 3-amino-1,4-diméthyl-9H-carbazoles diversement substitués en positions 6 et 8 est décrite. Leur activité cytotoxique, évaluée in vitro au moyen de la culture clonogénique de la leucémie L1210, dépend fortement de la nature et de la position des substituants. Le plus cytotoxique d'entre eux, le dérivé 3-amino 6-hydroxy, présente une cytotoxicité comparable à celle de l'acétate de N2-méthyl-9-hydroxy ellipticinium (NMHE). Ces résultats et ceux présentés dans les deux publications précédentes, permettent une discussion détaillée des relations structure-activité dans la série du 9H-carbazole et du 1,4-diméthyl 9H-carbazole et suggèrent, pour les dérivés du 3-amino 1,4-diméthyl 9H-carbazole, un mécanisme d'action proche de celui des dérivés de l'ellipticine.