Infections and systemic inflammation are associated with lower plasma concentration of insulin-like growth factor I among Malawian children

A protocol for a proof-of-concept randomized control trial testing increased protein quantity and quality in ready-to-use therapeutic food in improving linear growth among 6-23-month-old children with severe wasting in Malawi

INTRODUCTION

Ready-to-use therapeutic foods (RUTFs) have successfully promoted recovery from severe wasting and increased treatment coverage. However, RUTFs do not sufficiently improve linear growth, leaving many survivors of severe wasting at risk of persistent stunting, which is associated with high mortality risk, poor child development and non-communicable diseases in adulthood. High protein quantity and quality can stimulate linear growth.

AIM

The trial aims to assess whether higher-protein-RUTF leads to higher concentrations of markers of linear growth compared to standard RUTF among 6-23 months old children with severe wasting.

METHODS

We designed a higher protein quantity and quality RUTF for a proof-of-concept (PoC) double-blind randomized controlled trial.

OUTCOMES

The primary outcome is a change in insulin-like growth factor-1 (IGF-1), a hormone positively associated with linear growth after four weeks of treatment. Secondary outcomes include changes in ponderal and linear growth and in body composition from baseline to eight weeks later; plasma amino acid profile at four weeks; acceptability and safety.

IMPLICATIONS

These findings will help in informing the potential impact of increased protein in RUTF on linear growth when treating severe wasting towards conducting a larger clinical trial.

TRIAL REGISTRATION

The trial has been registered on clinicaltrial.gov (NCT05737472).

Malnourished Microbes: Host-Microbiome Interactions in Child Undernutrition

Childhood undernutrition is a major global health burden that is only partially resolved by nutritional interventions. Both chronic and acute forms of child undernutrition are characterized by derangements in multiple biological systems including metabolism, immunity, and endocrine systems. A growing body of evidence supports a role of the gut microbiome in mediating these pathways influencing early life growth. Observational studies report alterations in the gut microbiome of undernourished children, while preclinical studies suggest that this can trigger intestinal enteropathy, alter host metabolism, and disrupt immune-mediated resistance against enteropathogens, each of which contribute to poor early life growth. Here, we compile evidence from preclinical and clinical studies and describe the emerging pathophysiological pathways by which the early life gut microbiome influences host metabolism, immunity, intestinal function, endocrine regulation, and other pathways contributing to child undernutrition. We discuss emerging microbiome-directed therapies and consider future research directions to identify and target microbiome-sensitive pathways in child undernutrition.

Association between asymptomatic infections and linear growth in 18-24-month-old Malawian children

Inadequate diet and frequent symptomatic infections are considered major causes of growth stunting in low-income countries, but interventions targeting these risk factors have achieved limited success. Asymptomatic infections can restrict growth, but little is known about their role in global stunting prevalence. We investigated factors related to length-for-age Z-score (LAZ) at 24 months by constructing an interconnected network of various infections, biomarkers of inflammation (as assessed by alpha-1-acid glycoprotein [AGP]), and growth (insulin-like growth factor 1 [IGF-1] and collagen X biomarker [CXM]) at 18 months, as well as other children, maternal, and household level factors. Among 604 children, there was a continuous decline in mean LAZ and increased mean length deficit from birth to 24 months. At 18 months of age, the percentage of asymptomatic children who carried each pathogen was: 84.5% enterovirus, 15.5% parechovirus, 7.7% norovirus, 4.6% rhinovirus, 0.6% rotavirus, 69.6% Campylobacter, 53.8% Giardia lamblia, 11.9% malaria parasites, 10.2% Shigella, and 2.7% Cryptosporidium. The mean plasma IGF-1 concentration was 12.5 ng/ml and 68% of the children had systemic inflammation (plasma AGP concentration >1 g/L). Shigella infection was associated with lower LAZ at 24 months through both direct and indirect pathways, whereas enterovirus, norovirus, Campylobacter, Cryptosporidium, and malaria infections were associated with lower LAZ at 24 months indirectly, predominantly through increased systemic inflammation and reduced plasma IGF-1 and CXM concentration at 18 months.

Plasma biomarkers of hemoglobin loss in Plasmodium falciparum-infected children identified by quantitative proteomics

Anemia is common among young children infected with Plasmodium falciparum and severe malarial anemia (SMA) is a major cause of their mortality. Two major mechanisms cause malarial anemia: hemolysis of uninfected as well as infected erythrocytes and insufficient erythropoiesis. In a longitudinal birth cohort in Mali, we commonly observed marked hemoglobin reductions during P falciparum infections with a small proportion that progressed to SMA. We sought biomarkers of these processes using quantitative proteomic analysis on plasma samples from 9 P falciparum-infected children, comparing those with reduced hemoglobin (with or without SMA) vs those with stable hemoglobin. We identified higher plasma levels of circulating 20S proteasome and lower insulin-like growth factor-1 (IGF-1) levels in children with reduced hemoglobin. We confirmed these findings in independent enzyme-linked immunosorbent assay-based validation studies of subsets of children from the same cohort (20S proteasome, N = 71; IGF-1, N = 78). We speculate that circulating 20S proteasome plays a role in digesting erythrocyte membrane proteins modified by oxidative stress, resulting in hemolysis, whereas decreased IGF-1, a critical factor for erythroid maturation, might contribute to insufficient erythropoiesis. Quantitative plasma proteomics identified soluble mediators that may contribute to the major mechanisms underlying malarial anemia. This study was registered at www.clinicaltrials.gov as #NCT01168271.

Systemic Inflammation in the First 2 Weeks after Birth as a Determinant of Physical Growth Outcomes in Hospitalized Infants with Extremely Low Gestational Age

OBJECTIVE

To examine associations of systemic inflammation with growth outcomes at neonatal intensive care unit discharge or transfer among infants with extremely low gestational ages.

STUDY DESIGN

We studied 850 infants at born at 23-27 weeks of gestation. We defined inflammatory protein elevation as the highest quartile of C-reactive protein (CRP), Interleukin (IL)-6, tumor necrosis factor-∝, or IL-8 on postnatal days 1, 7, and 14. We compared z-scores of weight, length, and head circumference at neonatal intensive care unit discharge or transfer between infants with vs without inflammatory protein elevation, adjusting in linear regression for birth size z-score, sex, gestational age, diet, comorbidities, medications, and length of hospitalization.

RESULTS

The mean gestational age was 25 weeks (range, 23-27 weeks) and birth weight z-score 0.14 (range, -2.73 to 3.28). Infants with a high CRP on day 7 had lower weights at discharge or transfer (-0.17 z-score; 95% CI, -0.27 to -0.06) than infants without CRP elevation, with similar results on day 14. Infants with CRP elevation on day 14 were also shorter (-0.21 length z-scores; 95% CI, -0.38 to -0.04), and had smaller head circumferences (-0.18 z-scores; 95% CI, -0.33 to -0.04) at discharge or transfer. IL-6 elevation on day 14 was associated with lower weight (-0.12; 95% CI, -0.22 to -0.02); IL-6 elevation on day 7 was associated with shorter length (-0.27; 95% CI, -0.43 to -0.12). Tumor necrosis factor-∝ and IL-8 elevation on day 14 were associated with a lower weight at discharge or transfer.

CONCLUSIONS

Postnatal systemic inflammation may contribute to impaired nutrient accretion during a critical period in development in infants with extremely low gestational ages.

IGF-1 and IGFBP-3 in Inflammatory Cachexia

Inflammation induces a wide response of the neuroendocrine system, which leads to modifications in all the endocrine axes. The hypothalamic–growth hormone (GH)–insulin-like growth factor-1 (IGF-1) axis is deeply affected by inflammation, its response being characterized by GH resistance and a decrease in circulating levels of IGF-1. The endocrine and metabolic responses to inflammation allow the organism to survive. However, in chronic inflammatory conditions, the inhibition of the hypothalamic–GH–IGF-1 axis contributes to the catabolic process, with skeletal muscle atrophy and cachexia. Here, we review the changes in pituitary GH secretion, IGF-1, and IGF-1 binding protein-3 (IGFBP-3), as well as the mechanism that mediated those responses. The contribution of GH and IGF-1 to muscle wasting during inflammation has also been analyzed.