Systemic inflammation is negatively associated with early post discharge growth following acute illness among severely malnourished children - a pilot study

Therapeutic interventions targeting enteropathy in severe acute malnutrition modulate systemic and vascular inflammation and epithelial regeneration

BACKGROUND

Severe acute malnutrition (SAM) is the most life-threatening form of undernutrition, and children hospitalised with complications have unacceptably high mortality. Complicated SAM is a multisystem disease characterised pathophysiologically by muscle wasting, systemic inflammation, metabolic dysfunction, and malnutrition enteropathy including epithelial barrier dysfunction. There is a clear need for novel interventions to address the underlying pathogenic perturbations of complicated SAM.

METHODS

In this analysis of tertiary outcomes from a phase II multi-centre trial in Zambia and Zimbabwe, multiplex biomarkers were measured in 122 children (57% male) with SAM randomised following stabilisation ('baseline') to one of four interventions for 14 days to treat malnutrition enteropathy: budesonide, N-acetylglucosamine, colostrum, or teduglutide, compared with standard-of-care. Following measurement of 35 biomarkers from day 15 plasma samples using Luminex and ELISA, the dimensionality of biomarker data was reduced using principal component analysis.

FINDINGS

Both budesonide and colostrum reduced systemic inflammation (as measured by CD14, IL1-ra, CRP, and LBP), while children receiving colostrum had higher GLP2 and angiopoietin, and lower circulating lipopolysaccharide, suggesting better restoration of epithelial barrier function. N-acetylglucosamine, a precursor for epithelial glycosaminoglycan synthesis, increased biomarkers of epithelial regeneration (EGF, VEGF), and circulating growth factors (angiopoietin, IGFBP-3, and GCSF).

INTERPRETATION

Interventions aimed at ameliorating malnutrition enteropathy showed plausible effects on biomarkers of inflammation and epithelial regeneration, demonstrating an interdependence of systemic inflammation and enteropathy markers seen in structural analysis. Given the interplay between inflammation and tissue restoration in malnutrition, this mechanism of action supports larger trials to determine the clinical benefits of interventions, either alone or in combination, in children with complicated SAM.

FUNDING

This analysis of tertiary outcomes for the TAME trial was funded by a Wellcome grant to JPS (220566/Z/20/Z). The TAME trial was funded by a grant from the Medical Research Council (UK), number MR/P024033/1. AJP is funded by Wellcome (108065/Z/15/Z). Takeda UK provided teduglutide at a discounted price.

Systemic biological mechanisms underpin poor post-discharge growth among severely wasted children with HIV

In sub-Saharan Africa, children with severe malnutrition (SM) and HIV have substantially worse outcomes than children with SM alone, facing higher mortality risk and impaired nutritional recovery post-hospitalisation. Biological mechanisms underpinning this risk remain incompletely understood. This case-control study nested within the CHAIN cohort in Kenya, Uganda, Malawi, and Burkina Faso examined effect of HIV on six months post-discharge growth among children with SM and those at risk of malnutrition, assessed proteomic signatures associated with HIV in these children, and investigated how these systemic processes impact post-discharge growth in children with SM. Using SomaScanTM assay, 7335 human plasma proteins were quantified. Linear mixed models identified HIV-associated biological processes and their associations with post-discharge growth. Using structural equation modelling, we examined directed paths explaining how HIV influences post-discharge growth. Here, we show that at baseline, HIV is associated with lower anthropometry. Additionally, HIV is associated with protein profiles indicating increased complement activation and decreased insulin-like growth factor signalling and bone mineralisation. HIV indirectly affects post-discharge growth by influencing baseline anthropometry and modulating proteins involved in bone mineralisation and humoral immune responses. These findings suggest specific biological pathways linking HIV to poor growth, offering insights for targeted interventions in this vulnerable population.

Inflammation and epithelial repair predict mortality, hospital readmission, and growth recovery in complicated severe acute malnutrition

Severe acute malnutrition (SAM) is the most high-risk form of undernutrition, particularly when children require hospitalization for complications. Complicated SAM is a multisystem disease with high inpatient and postdischarge mortality, especially in children with comorbidities such as HIV; however, the underlying pathogenesis of complicated SAM is poorly understood. Targeted multiplex biomarker analysis in children hospitalized with SAM (n = 264) was conducted on plasma samples, and inflammatory markers were assessed on stool samples taken at recruitment, discharge, and 12 to 24 and 48 weeks after discharge from three hospitals in Zimbabwe and Zambia. Compared with adequately nourished controls (n = 173), we found that at baseline, complicated SAM was characterized by systemic, endothelial, and intestinal inflammation, which was exacerbated by HIV infection. This persisted over 48 weeks despite nutritional recovery and was associated with children's outcomes. Baseline plasma concentrations of vascular endothelial growth factor, glucagon-like peptide-2, and intestinal fatty acid-binding protein were independently associated with lower mortality or hospital readmission over the following 48 weeks. Following principal components analysis of baseline biomarkers, higher scores of a component representing growth factors was associated with greater weight-for-height z score recovery and lower mortality or hospital readmission over the 48 weeks. Conversely, components representing higher gut and systemic inflammation were associated with higher mortality or hospital readmission. These findings highlight the interplay between inflammation, which damages tissues, and growth factors, which mediate endothelial and epithelial regeneration, and support further studies investigating interventions to reduce inflammation and promote epithelial repair as an approach to reducing mortality and improving nutritional recovery.

Inflammation: the driver of poor outcomes among children with severe acute malnutrition?

Severe acute malnutrition (SAM) is the most life-threatening form of undernutrition and underlies at least 10% of all deaths among children younger than 5 years in low-income countries. SAM is a complex, multisystem disease, with physiological perturbations observed in conjunction with the loss of lean mass, including structural and functional changes in many organ systems. Despite the high mortality burden, predominantly due to infections, the underlying pathogenic pathways remain poorly understood. Intestinal and systemic inflammation is heightened in children with SAM. Chronic inflammation and its consequent immunomodulation may explain the increased morbidity and mortality from infections in children with SAM, both during hospitalization and in the longer term after discharge. Recognition of the role of inflammation in SAM is critical in considering new therapeutic targets in this disease, which has not seen a transformational approach to treatment for several decades. This review highlights the central role of inflammation in the wide-ranging pathophysiology of SAM, as well as identifying potential interventions that have biological plausibility based on evidence from other inflammatory syndromes.

Severe acute malnutrition promotes bacterial binding over proinflammatory cytokine secretion by circulating innate immune cells

Children with severe acute malnutrition (SAM) have high infectious mortality and morbidity, implicating defects in their immune defenses. We hypothesized that circulating innate immune cells from children (0 to 59 months) hospitalized with SAM in Zambia and Zimbabwe (n = 141) have distinct capacity to respond to bacteria relative to adequately nourished healthy controls (n = 92). SAM inpatients had higher neutrophil and monocyte Escherichia coli binding capacity but lower monocyte activation and proinflammatory mediator secretion in response to lipopolysaccharide or heat-killed Salmonella typhimurium than controls. Among SAM cases, wasting severity was negatively associated with cytokine secretion, children with HIV had lower monocyte activation, and the youngest children released the least myeloperoxidase upon stimulation. Inpatient bacterial binding capacity and monocyte activation were associated with higher odds of persistent SAM at discharge, a risk factor for subsequent mortality. Thus, SAM shifts innate immune cell function, favoring bacterial containment over proinflammatory activation, which may contribute to health deficits after discharge.

How do children with severe underweight and wasting respond to treatment? A pooled secondary data analysis to inform future intervention studies

Children with weight-for-age z-score (WAZ) <-3 have a high risk of death, yet this indicator is not widely used in nutrition treatment programming. This pooled secondary data analysis of children aged 6-59 months aimed to examine the prevalence, treatment outcomes, and growth trajectories of children with WAZ <-3 versus children with WAZ ≥-3 receiving outpatient treatment for wasting and/or nutritional oedema, to inform future protocols. Binary treatment outcomes between WAZ <-3 and WAZ ≥-3 admissions were compared using logistic regression. Recovery was defined as attaining mid-upper-arm circumference ≥12.5 cm and weight-for-height z-score ≥-2, without oedema, within a period of 17 weeks of admission. Data from 24,829 children from 9 countries drawn from 13 datasets were included. 55% of wasted children had WAZ <-3. Children admitted with WAZ <-3 compared to those with WAZ ≥-3 had lower recovery rates (28.3% vs. 48.7%), higher risk of death (1.8% vs. 0.7%), and higher risk of transfer to inpatient care (6.2% vs. 3.8%). Growth trajectories showed that children with WAZ <-3 had markedly lower anthropometry at the start and end of care, however, their patterns of anthropometric gains were very similar to those with WAZ ≥-3. If moderately wasted children with WAZ <-3 were treated in therapeutic programmes alongside severely wasted children, we estimate caseloads would increase by 32%. Our findings suggest that wasted children with WAZ <-3 are an especially vulnerable group and those with moderate wasting and WAZ <-3 likely require a higher intensity of nutritional support than is currently recommended. Longer or improved treatment may be necessary, and the timeline and definition of recovery likely need review.