Analytical review: host defense mechanisms in protein-energy malnutrition

Plasma proteome profiling reveals metabolic and immunologic differences between Anorexia Nervosa subtypes

AIMS/HYPOTHESIS

Anorexia Nervosa (AN) is a severe psychiatric disorder of an unknown etiology with a crude mortality rate of about 5 % per decade, making it one of the deadliest of all psychiatric illnesses. AN is broadly classified into two main subtypes, restricting and binge/purging disorder. Despite extensive research efforts during several decades, the underlying pathophysiology of AN remains poorly understood. In this study, we aimed to identify novel protein biomarkers for AN by performing a proteomics analysis of fasting plasma samples from 78 females with AN (57 restrictive and 21 binge/purge type) and 70 healthy controls.

METHODS

Using state-of-the-art mass spectrometry-based proteomics technology in conjunction with an advanced bioinformatics pipeline, we quantify >500 plasma proteins.

RESULTS

Differential expression analysis and correlation of proteomics data with clinical variables led to identification of a panel of novel protein biomarkers with potential pathophysiological significance for AN. Our findings demonstrate evidence of a humoral immune system response, altered lipid metabolism and potential alteration of plasma cells in AN patients. Additionally, we stratified AN patients based on the quantified proteins and suggest a potential autoimmune nature in the restrictive subtype of AN.

CONCLUSIONS/INTERPRETATION

In summary, on top of biomarkers of AN subtypes, this study provides a comprehensive map of plasma proteins that constitute a resource for further studies of the pathophysiology of AN.

Anorexia Nervosa and the Immune System-A Narrative Review

The pathogenesis of an increasing number of chronic diseases is being attributed to effects of the immune system. However, its role in the development and maintenance of anorexia nervosa is seemingly under-appreciated. Yet, in examining the available research on the immune system and genetic studies in anorexia nervosa, one becomes increasingly suspicious of the immune system’s potential role in the pathophysiology of anorexia nervosa. Specifically, research is suggestive of increased levels of various pro-inflammatory cytokines as well as the spontaneous production of tumor necrosis factor in anorexia nervosa; genetic studies further support a dysregulated immune system in this disorder. Potential contributors to this dysregulated immune system are discussed including increased oxidative stress, chronic physiological/psychological stress, changes in the intestinal microbiota, and an abnormal bone marrow microenvironment, all of which are present in anorexia nervosa.

The effects of malnutrition on murine peritoneal macrophages

Differences were detected between peritoneal macrophages (both resident and elicited) from mice on a low protein diet and from normal animals. The concentration of resident peritoneal macrophages was lower in animals on low protein diets than in normal controls. Although total protein (and therefore cell mass) of resident macrophages from malnourished mice was increased, their contents of thiamine pyrophosphatase, succinate dehydrogenase, and non-specific esterase were disproportionately reduced. In addition they did not ingest as many glutaraldehyde-fixed sheep erythrocytes or attach to as many adherent C3b sensitized sheep red blood cells as those from normal animals, although reduction of nitroblue tetrazolium was unaffected. Initially (24 hr after thioglycollate), elicited macrophages from malnourished mice did not divide as frequently as those from normal mice but by 48 hr the differences were insignificant. The elicited macrophage possessed lower levels of total protein (indicating a reduced cell mass); the levels of acid phosphatase, thiamine pyrophosphatase, succinate dehydrogenase, and nonspecific esterase and nitroblue reducing activity were also proportionately reduced. They ingested fewer glutaraldehyde-fixed erythrocytes and reacted with fewer C3b sensitised sheep red blood cells than those from normal mice; ingestion of IgG-coated sheep erythrocytes, on the other hand, was somewhat increased. These abnormalities may influence adversely the efficiency of early phlogistic responses and favor the establishment of infection in malnourished animals.

Follow-up of a randomized trial for oat cell carcinoma evaluating the efficacy of peripheral intravenous nutrition (PIVN) as adjunct treatment

A randomized trial was initiated to compare the effects of peripheral i.v. nutrition (PIVN)-associated chemotherapy (adriamycin, vincristine, VP-16-213, and cyclophosphamide) versus a chemotherapy control group in patients with oat cell lung carcinoma. Thirty-nine evaluable patients were randomized. The test group included 19 patients, whereas 20 were followed in the control group. PIVN was scheduled each day the patient underwent chemotherapy. Each patient received 1,550 kcal day which included 10% glucose, 20% lipids, and amino acids which may or may not have been mixed in the same infusion bottle. The results show ten PIVN patients presently in complete remission at the end of three courses of treatment, compared to nine over the same time period in the chemotherapy control group. Thirty-three percent of patients are still alive after 15 months after the beginning of treatment. There was no significant difference in either general health or side effects, frequency or duration of complete remission, or survival time. After 1 year of treatment, 8 of 19 PIVN patients are still in complete remission, compared to 7 of 20 patients in the control groups.

The effects of malnutrition on secretory and cellular immune processes

About 15 million children under 5 years of age die each year due to suppressed immunity and the resulting increased infection. In severely malnourished children and animals some immune systems such as T-cell function, secretory IgA and complement are significantly suppressed. Other systems, such as the serum IgG or IgA, are normal or even elevated. Some of these changes are apparently caused by nutritional stress while others may be due to stimulation by increased incidence of infection and antigen load. On the other hand, marginal malnutrition stimulates increased phagocytosis and T-cell function with increased immunity to cancer but decreased resistance to certain microbial agents. The mechanisms of immune suppression by malnutrition, persistence of these effects after renutrition, and the effect of maternal malnutrition on newborn immunity are critically reviewed. Possible non-nutritional means of rapid immunological restoration of malnourished children are described.

[Nestlé Foundation studies of nutritional problems in the 3d world]

An outline is given of the aims and activities of the Nestlé Foundation, notably the inquiries performed at the Study center at Adiopodoumé (Ivory Coast) about the nutrition situation, and the efforts made there to improve the protein intake by introducing new food-stuffs of high protein content.

Chemotactic defects in severe combined immunodeficiency

Cellular and humoral components of leukotaxis were studied serially in four male infants with severe combined immunodeficiency disease. Two of the four, both lacking B and T cells initially, had a significant defect in neutrophil and monocyte chemotaxis. The other two, who had a high number of immunoglobulin-bearing cells (B cells), did not have these cellular abnormalities. It contrast, defective generation of chemotactic factor following endotoxin activation was observed in all patients. The defects were corrected coincident with or soon after successful engraftment of either bone marrow or fetal tissues. The reported deficiencies may be another manifestation of the heterogeneity in SCID.