Limited value of serum ferritin in evaluating iron status in children with protein-energy malnutrition

Anemia in infancy is associated with alterations in systemic metabolism and microbial structure and function in a sex-specific manner: an observational study

Background

Anemia is a term that describes low hemoglobin concentrations and can result from micronutrient deficiencies, infection, or low birth weight. Early-life anemia, particularly iron-deficiency anemia (IDA) is associated with several negative metabolic, developmental, and cognitive outcomes, some of which persist into adulthood.

Objective

The aim of this study was to investigate alterations in systemic metabolism and fecal microbial diversity and functionality associated with anemia and IDA in male and female infants from Iquitos, Peru.

Design

Cross-sectional stool and serum samples were collected from 95 infants (53 boys and 42 girls) at 12 mo of age. The fecal microbiome was assessed by using 16S ribosomal RNA gene sequencing, and the fecal and serum metabolomes were quantified using 1H-nuclear magnetic resonance.

Results

The prevalence of anemia was 64%, with a greater proportion of anemia in male infants attributed to iron deficiency. Metabolically, anemia was associated with decreased concentrations of tricarboxylic acid cycle metabolites in both sexes (males: succinate, P = 0.031; females: fumarate, P = 0.028). In addition, anemic male infants exhibited significantly lower serum concentrations of several amino acids compared with nonanemic male infants. Although no specific structural or functional differences in the microbiota were observed with anemia in general, likely due the heterogeneity of its etiology, IDA affected the microbiome both structurally and functionally. Specifically, the abundance of butyrate-producing bacteria was lower in IDA subjects of both sexes than in nonanemic, non-iron-deficient subjects of the same sex (females: Butyricicoccus, P = 0.041; males: Coprococcus, P = 0.010; Roseburia, P = 0.027). IDA male infants had higher concentrations of 4-hydroxyphenyllactate (P < 0.001) and putrescine (P = 0.042) than those without IDA, whereas IDA female infants exhibited higher concentrations of leucine (P = 0.011) and valine (P = 0.003).

Conclusions

Sexually dimorphic differences associated with anemia and IDA are suggestive of greater mitochondrial dysfunction and oxidative stress in male infants compared with female infants, and alterations in microbial structure and function may further contribute. Differences in metabolic pathways associated with anemia and IDA in each sex point to potential mechanisms for the associated lasting cognitive deficits. This trial is registered at clinicaltrials.gov as NCT03377777.

Hematologic and bone marrow changes in children with protein-energy malnutrition

BACKGROUND

All systems in an organism are affected by protein-energy malnutrition (PEM), but one of the worst affected is the hematopoietic system. Today PEM remains a very serious problem in developing countries. We examined the relationships between clinical features, hematological, and bone marrow changes with severe PEM from Turkey.

METHOD

We evaluated 34 (11 females and 23 males) consecutive cases of severe PEM, with no underlying diseases aged 3-20 months. The clinical nutritional conditions of the patients were determined using the Wellcome-Trust PEM classification. Ten of the patients were in the Marasmic-Kwashiorkor (M-K) group, 10 were in the Kwashiorkor (KW) group, and 14 were in the Marasmic (M) group. Full blood count, protein, albumin, serum iron (SI), iron-binding capacity (TIBC), ferritin, vitamin B12, folic acid, complement-3 (C3), complement-4 (C4), and bone marrow were investigated in all groups.

RESULTS

Anemia was detected in 97% of patients. We determined serum iron levels were low in 67.6% of the patients, TS levels were low in 76.4% of the patients and ferritin levels were low in 20.5%. The level of vitamin B12 was normal in all patients. Bone marrow analysis showed erythroid series hypoplasia in 28.5% of patients in the M group, 50% in the KW group, and 30% in the M-K group. Marrow iron was absent in 58.8% of patients.

CONCLUSION

The most common hematologic change in the children with PEM was anemia and major cause of anemia was iron deficiency in this study. Patients with severe PEM have normal Vit B12 and serum folate levels. Most of the patients with severe PEM had normal cellularity with megaloblastic and dysplastic changes in bone marrow due to the inadequate and imbalanced intake of protein and energy.

Iron, thermoregulation, and metabolic rate

Iron plays an important role, not only in oxygen delivery to the tissues, but also as a cofactor with several enzymes involved in energy metabolism and thermoregulation. As a result, much research has been dedicated to understanding the ramifications of iron depletion and iron deficiency anemia on the physiological functions of these enzymes. There is evidence to suggest that iron depletion and iron deficiency anemia cause physiological changes in the body not only during exercise, but also under resting conditions. Both rat and human studies have produced results revealing elevated levels of norepinephrine in the blood and urine of iron-deficient anemic subjects. These studies also provide evidence to suggest that elevation in metabolic rate may ultimately lead to slower growth rates and lower body weights in iron-deficient anemic animals and humans. The focus of this review is on the effects of iron deficiency on metabolic rate and thermoregulation. Prior to this discussion, a brief background on iron is presented.

Iron nutrition and anaemia in a malaria-endemic environment: haematological investigation of the Gidra-speaking population in lowland Papua New Guinea

Blood examination was conducted for the four Gidra-speaking village groups in Papua New Guinea, who were characterized by high Fe intake and high malaria prevalence with marked inter-village differences. The northern riverine villagers, whose Fe intake was higher than the other three village groups, did not suffer from Fe-deficiency anaemia in their malaria-endemic environment; nor did the inland villagers, with their second highest Fe intake and their malaria-free environment, suffer from Fe-deficiency anaemia. However, several individuals of the southern riverine village suffered from anaemia in a malaria-endemic environment, although their Fe intake was almost the same as the inland villagers'. A considerable proportion of the coastal villagers were anaemic, reflecting the lowest Fe intake and the highest malaria prevalence. An inter-village comparison of the relationships between haemoglobin levels and transferrin saturation revealed that the southern riverine villagers needed smaller amounts of circulating Fe for erythropoiesis than the northern riverine and inland villagers, reflecting the long-term human-environment conditions such as the density of malaria vectors and the people's dietary habits. Fe supplementation was not judged effective against hypoferraemia and/or anaemia in such a population. As the incidence of malaria had no significant long-lasting effect on Fe stores or circulating Fe concentration, but did have an effect on anaemia, the hypothesis that malaria causes a transfer of Fe from the blood to parenchymal tissues as a defence against infectious diseases was not supported.

Investigation of the nutritional state of children in a Congolese village. I. Anthropometrical data, plasma prealbumin, albumin, immunoglobulins, ferritin, C-reactive protein, circulating immune complexes

The nutritional status of an unselected group of 111 children from the village of Bouansa, People's Republic of the Congo, was studied. Comprehensive clinical examinations, anthropometrical measurements and analysis of albumin, prealbumin, ferritin, C-reactive protein (CRP), IgA, IgG, IgM, IgE, IgG- and IgM-circulating immune complexes (CIC) were carried out. The results show, by anthropometrical classification, a high prevalence of moderate malnutrition. Low levels of plasma proteins and high levels of immunoglobulins and CIC were found. No correlation between anthropometrical classification and plasma proteins was established. Children with increased levels of CRP showed low prealbumin values and increased levels of ferritin. Patterns of immunoglobulins and CIC were close to those found in other studies in tropical countries. To evaluate the anthropometrical and biochemical findings it is necessary to take into consideration the apparently healthy appearance of the children, which shows the degree of adaptation to the limited availability of food and the high rate of acute and chronic infections.

Ultrastructure and cell cycle distribution of bone marrow cells in protein-energy malnutrition

Bone marrow aspirates from four children with kwashiorkor and three with marasmus were studied using the techniques of electron microscopy and combined Feulgen microspectrophotometry and 3H-thymidine autoradiography. The majority of the erythroblasts were ultrastructurally normal, the distribution of the early polychromatic erythroblasts between the various stages of the cell cycle was normal or almost normal, and the macrophages did not contain ingested erythroblasts. Since erythropoietin production has been shown to be normal in protein-energy malnutrition, these findings suggest that at least in some cases of PEM the impairment of erythropoiesis results primarily from an abnormality in the erythroid progenitor cell pool rather than from dyserythropoiesis and ineffective erythropoiesis. In one afebrile and apparently uninfected patient with marasmus, a substantial proportion of the neutrophil granulocytes and their more mature precursors contained electron-dense, myelin-containing intracytoplasmic structures which were presumed to be abnormal primary granules. In four of the patients, the 3H-thymidine labelling index of the neutrophil promyelocyte-myelocyte pool was increased. In addition, in all of the cases, neutrophils at various stages of degradation were readily found within the cytoplasm of some of the macrophages. Thus, whereas the techniques employed did not reveal a major disturbance in the morphologically recognizable precursor cells of the erythroid series in PEM, they demonstrated some abnormalities in such cells of the neutrophil series.