Interactions between fecal gut microbiome, enteric pathogens, and energy regulating hormones among acutely malnourished rural Gambian children.

BACKGROUND: The specific roles that gut microbiota, known pathogens, and host energy-regulating hormones play in the pathogenesis of non-edematous severe acute malnutrition (marasmus SAM) and moderate acute malnutrition (MAM) during outpatient nutritional rehabilitation are yet to be explored. METHODS: We applied an ensemble of sample-specific (intra- and inter-modality) association networks to gain deeper insights into the pathogenesis of acute malnutrition and its severity among children under 5 years of age in rural Gambia, where marasmus SAM is most prevalent. FINDINGS: Children with marasmus SAM have distinct microbiome characteristics and biologically-relevant multimodal biomarkers not observed among children with moderate acute malnutrition. Marasmus SAM was characterized by lower microbial richness and biomass, significant enrichments in Enterobacteriaceae, altered interactions between specific Enterobacteriaceae and key energy regulating hormones and their receptors. INTERPRETATION: Our findings suggest that marasmus SAM is characterized by the collapse of a complex system with nested interactions and key associations between the gut microbiome, enteric pathogens, and energy regulating hormones.  Further exploration of these systems will help inform innovative preventive and therapeutic interventions. FUNDING: The work was supported by the UK Medical Research Council (MRC; MC-A760-5QX00) and the UK Department for International Development (DFID) under the MRC/DFID Concordat agreement; Bill and Melinda Gates Foundation (OPP 1066932) and the National Institute of Medical Research (NIMR), UK. This network analysis was supported by NIH U54GH009824 [CLD] and NSF OCE-1558453 [CLD].

Metabolomic changes in severe acute malnutrition suggest hepatic oxidative stress: a secondary analysis.

Severe acute malnutrition (SAM), due to poor energy and/or protein intake, is associated with poor growth, depressed immune function, and long-term impacts on metabolic function. As the liver is a major metabolic organ and malnutrition poses metabolic stress, we hypothesize that SAM will be associated with alterations in the hepatic metabolome reflective of oxidative stress, gluconeogenesis, and ketogenesis. Thus, the purpose of this secondary analysis was to understand how SAM alters hepatic metabolism using a piglet model. Weanling piglets were feed either a reference (REF) or protein-energy deficient diet (MAL) for 5 weeks. After dietary treatment MAL piglets were severely underweight (weight-for-age Z-score of -3.29, Welch's t test, P = .0007), moderately wasted (weight-for-length Z-score of-2.49, Welch's t test, P = .003), and tended toward higher hepatic triglyceride content (Welch's t test, P = .07). Hematologic and blood biochemical measurements were assessed at baseline and after dietary treatment. The hepatic metabolome was investigated using 1H-NMR spectroscopy. Hepatic concentrations of betaine, cysteine, and glutathione tended to be lower in MAL (Welch's t test with FDR correction, P < .1), while inosine, lactate, and methionine sulfoxide concentrations were higher in MAL (inosine: P = .0448, lactate: P = .0258, methionine sulfoxide: P = .0337). These changes suggest that SAM is associated with elevated hepatic oxidative stress, increased gluconeogenesis, and alterations in 1-carbon metabolism.

Amino acid-enriched plant-based RUTF treatment was not inferior to peanut-milk RUTF treatment in restoring plasma amino acid levels among patients with oedematous or non-oedematous malnutrition.

Ready-to-use therapeutic food (RUTF) with adequate quality protein is used to treat children with oedematous and non-oedematous severe acute malnutrition (SAM). The plasma amino acid (AA) profile reflects the protein nutritional status; hence, its assessment during SAM treatment is useful in evaluating AA delivery from RUTFs. The objective was to evaluate the plasma AAs during the treatment of oedematous and non-oedematous SAM in community-based management of acute malnutrition (CMAM) using amino acid-enriched plant-based RUTFs with 10% milk (MSMS-RUTF) or without milk (FSMS-RUTF) compared to peanut milk RUTF (PM-RUTF). Plasma AA was measured in a non-blinded, 3-arm, parallel-group, simple randomized controlled trial conducted in Malawi. The RUTFs used for SAM were FSMS-RUTF, MSMS-RUTF or PM-RUTF. A non-inferiority hypothesis was tested to compare plasma AA levels from patients treated with FSMS-RUTF or MSMS-RUTF with those from patients treated with PM-RUTF at discharge. For both types of SAM, FSMS-RUTF and MSMS-RUTF treatments were non-inferior to the PM-RUTF treatment in restoration of the EAA and cystine except that for FSMS-RUTF, methionine and tryptophan partially satisfied the non-inferiority criteria in the oedematous group. Amino-acid-enriched milk-free plant-source-protein RUTF has the potential to restore all the EAA, but it is possible that enrichment with amino acids may require more methionine and tryptophan for oedematous children.

Childhood severe acute malnutrition is associated with metabolic changes in adulthood.

BACKGROUNDSevere acute malnutrition (SAM) is a major contributor to global mortality in children under 5 years. Mortality has decreased; however, the long-term cardiometabolic consequences of SAM and its subtypes, severe wasting (SW) and edematous malnutrition (EM), are not well understood. We evaluated the metabolic profiles of adult SAM survivors using targeted metabolomic analyses.METHODSThis cohort study of 122 adult SAM survivors (SW = 69, EM = 53) and 90 age-, sex-, and BMI-matched community participants (CPs) quantified serum metabolites using direct flow injection mass spectrometry combined with reverse-phase liquid chromatography. Univariate and sparse partial least square discriminant analyses (sPLS-DAs) assessed differences in metabolic profiles and identified the most discriminative metabolites.RESULTSSeventy-seven metabolite variables were significant in distinguishing between SAM survivors (28.4 ± 8.8 years, 24.0 ± 6.1 kg/m2) and CPs (28.4 ± 8.9 years, 23.3 ± 4.4 kg/m2) (mean ± SDs) in univariate and sPLS-DA models. Compared with CPs, SAM survivors had less liver fat; higher branched-chain amino acids (BCAAs), urea cycle metabolites, and kynurenine/tryptophan (KT) ratio (P < 0.001); and lower ß-hydroxybutyric acid and acylcarnitine/free carnitine ratio (P < 0.001), which were both associated with hepatic steatosis (P < 0.001). SW and EM survivors had similar metabolic profiles as did stunted and nonstunted SAM survivors.CONCLUSIONAdult SAM survivors have distinct metabolic profiles that suggest reduced ß-oxidation and greater risk of type 2 diabetes (BCAAs, KT ratio, urea cycle metabolites) compared with CPs. This indicates that early childhood SAM exposure has long-term metabolic consequences that may worsen with age and require targeted clinical management.FUNDINGHealth Research Council of New Zealand, Caribbean Public Health Agency, Centre for Global Child Health at the Hospital for Sick Children. DST is an Academic Fellow and a Restracomp Fellow at the Centre for Global Child Health. GBG is a postdoctoral fellow of the Research Foundation Flanders.

Association between admission criteria and body composition among young children with moderate acute malnutrition, a cross-sectional study from Burkina Faso.

Children with moderate acute malnutrition (MAM) are treated based on low weight-for-length z-score (WLZ), low mid-upper arm circumference (MUAC) or both. This study aimed to assess associations of admission criteria and body composition (BC), to improve treatment of MAM. We undertook a cross-sectional study among 6-23 months old Burkinabe children with MAM. Fat-free (FFM) and fat mass (FM) were determined by deuterium dilution and expressed as FFM (FFMI) and FM index (FMI). Of 1,489 children, 439 (29.5%) were recruited by low MUAC only (MUAC-O), 734 (49.3%) by low WLZ and low MUAC (WLZ-MUAC) and 316 (21.2%) by low WLZ only (WLZ-O). Thus, 1,173 (78.8%) were recruited by low MUAC, with or without low WLZ (ALL-MUAC). After adjustments, WLZ-O had 89 g (95% confidence interval (CI) 5; 172) lower FFM compared to MUAC-O. Similarly, WLZ-O had 0.89 kg/m2 (95% CI 0.77; 1.01) lower FFMI compared to MUAC-O, whereas there was no difference for FMI. However, boys included by WLZ-O compared to MUAC-O had 0.21 kg/m2 (95% CI 0.05; 0.38) higher FMI. In contrast, girls included by WLZ-O had 0.17 (95% CI 0.01; 0.33) kg/m2 lower FMI compared to MUAC-O (interaction, p = 0.002). We found that different criteria for admission into MAM treatment programmes select children with differences in BC, especially FFMI.Trial registration: ISRCTN42569496.

Acute malnutrition recovery energy requirements based on mid-upper arm circumference: Secondary analysis of feeding program data from 5 countries, Combined Protocol for Acute Malnutrition Study (ComPAS) Stage 1.

BACKGROUND: Severe and moderate acute malnutrition (SAM and MAM) are currently treated with different food products in separate treatment programs. The development of a unified and simplified treatment protocol using a single food product aims to increase treatment program efficiency and effectiveness. This study, the first stage of the ComPAS trial, sought to assess rate of growth and energy requirements among children recovering from acute malnutrition in order to design a simplified, MUAC-based dosage protocol. METHODS: We obtained secondary data from patient cards of children aged 6-59 months recovering from SAM in outpatient therapeutic feeding programs (TFPs) and from MAM in supplementary feeding programs (SFPs) in five countries in Africa and Asia. We used local polynomial smoothing to assess changes in MUAC and proportional weight gain between clinic visits and assessed their normalized differences for a non-zero linear trend. We estimated energy needs to meet or exceed the growth observed in 95% of visits. RESULTS: This analysis used data from 5518 patients representing 33942 visits. Growth trends in MUAC and proportional weight gain were not significantly different, each lower at higher MUAC values: MUAC growth averaged 2mm/week at lower MUACs (100 to <110mm) and 1mm/week at higher MUACs (120mm to <125mm); and proportional weight gain declined from 3.9g/kg/day to 2.4g/kg/day across the same MUAC values. In 95% of visits by children with a MUAC 100mm to <125mm who were successfully treated, energy needs could be met or exceeded with 1,000 kilocalories a day. CONCLUSION: Two 92g sachets of Ready-to-Use Therapeutic Food (RUTF) (1,000kcal total) is proposed to meet the estimated total energy requirements of children with a MUAC 100mm to <115mm, and one 92g sachet of RUTF (500kcal) is proposed to meet half the energy requirements of children with a MUAC of 115 to <125mm. A simplified, combined protocol may enable a more holistic continuum of care, potentially contributing to increased coverage for children suffering from acute malnutrition.

Severe Acute Malnutrition Results in Lower Lumefantrine Exposure in Children Treated With Artemether-Lumefantrine for Uncomplicated Malaria.

Severe acute malnutrition (SAM) has been reported to be associated with increased malaria morbidity in Sub-Saharan African children and may affect the pharmacology of antimalarial drugs. This population pharmacokinetic (PK)-pharmacodynamic study included 131 SAM and 266 non-SAM children administered artemether-lumefantrine twice daily for 3 days. Lumefantrine capillary plasma concentrations were adequately described by two transit-absorption compartments followed by two distribution compartments. Allometrically scaled body weight and an enzymatic maturation effect were included in the PK model. Mid-upper arm circumference was associated with decreased absorption of lumefantrine (25.4% decreased absorption per 1 cm reduction). Risk of recurrent malaria episodes (i.e., reinfection) were characterized by an interval-censored time-to-event model with a sigmoid maximum-effect model describing the effect of lumefantrine. SAM children were at risk of underexposure to lumefantrine and an increased risk of malaria reinfection compared with well-nourished children. Research on optimized regimens should be considered for malaria treatment in malnourished children.

Hypoallergenic and anti-inflammatory feeds in children with complicated severe acute malnutrition: an open randomised controlled 3-arm intervention trial in Malawi.

Intestinal pathology in children with complicated severe acute malnutrition (SAM) persists despite standard management. Given the similarity with intestinal pathology in non-IgE mediated gastrointestinal food allergy and Crohn's disease, we tested whether therapeutic feeds effective in treating these conditions may benefit children with complicated SAM. After initial clinical stabilisation, 95 children aged 6-23 months admitted at Queen Elizabeth Central Hospital, Blantyre, Malawi between January 1st and December 31st, 2016 were allocated randomly to either standard feeds, an elemental feed or a polymeric feed for 14 days. Change in faecal calprotectin as a marker of intestinal inflammation and the primary outcome was similar in each arm: elemental vs. standard 4.1 µg/mg stool/day (95% CI, -29.9, 38.15; P = 0.81) and polymeric vs. standard 10 (-23.96, 43.91; P = 0.56). Biomarkers of intestinal and systemic inflammation and mucosal integrity were highly abnormal in most children at baseline and abnormal values persisted in all three arms. The enteropathy in complicated SAM did not respond to either standard feeds or alternative therapeutic feeds administered for up to 14 days. A better understanding of the pathogenesis of the gut pathology in complicated SAM is an urgent priority to inform the development of improved therapeutic interventions.

Intestinal pathogen clearance in children with severe acute malnutrition is unrelated to inpatient morbidity.

BACKGROUND & AIMS: Children with Severe Acute Malnutrition (SAM) often suffer from diarrhea, which is associated with increased mortality. The contribution of intestinal bacteria, parasites and viruses to morbidity such as diarrhea in SAM remains poorly understood. To evaluate their association with clinical outcomes, we detected stool pathogens in children with SAM at hospital admission and after clinical stabilization prior to discharge. METHODS: 15 intestinal pathogens, fecal calprotectin and C-reactive protein (CRP) were determined at admission and after clinical stabilization in children aged 8-59 months (n = 47) hospitalized in Malawi for complicated SAM. Differences in fecal pathogens, intestinal and systemic inflammation, and clinical outcomes between time points were evaluated using the Wilcoxon Signed-Rank test or Wilcoxon rank-sum test. RESULTS: On admission pathogens were present in nearly all children and after clinical stabilization many were cleared with only 55% of children still harboring a pathogen (89% vs. 55%, p = 0.001). Nosocomial infections were infrequent. The pathogens Giardia lamblia and Shigella spp. were most likely to persist. After clinical stabilization, fecal calprotectin was higher in children harboring a pathogen (median (IQR): 383 mg/kg (903-149 mg/kg) vs 140 mg/kg (300-71 mg/kg), p = 0.03). CRP did not correlate with fecal calprotectin levels nor was it associated with pathogen detection. Presence of stool pathogens was not associated with clinical outcomes such as diarrhea. CONCLUSIONS: Fecal pathogens were very common and cleared in most children with complicated SAM treated with antibiotics. The presence of stool pathogens after stabilization was associated with increased intestinal inflammation but not with clinical outcomes. (http://www.isrctn.com/ISRCTN13916953).

Molecular Evidence for Differential Long-term Outcomes of Early Life Severe Acute Malnutrition.

BACKGROUND: Severe acute malnutrition (SAM) in infants may present as one of two distinct syndromic forms: non-edematous (marasmus), with severe wasting and no nutritional edema; or edematous (kwashiorkor) with moderately severe wasting. These differences may be related to developmental changes prior to the exposure to SAM and phenotypic changes appear to persist into adulthood with differences between the two groups. We examined whether the different response to SAM and subsequent trajectories may be explained by developmentally-induced epigenetic differences. METHODS: We extracted genomic DNA from muscle biopsies obtained from adult survivors of kwashiorkor (n=21) or marasmus (n=23) and compared epigenetic profiles (CpG methylation) between the two groups using the Infinium® 450K BeadChip array. FINDINGS: We found significant differences in methylation of CpG sites from 63 genes in skeletal muscle DNA. Gene ontology studies showed significant differential methylation of genes in immune, body composition, metabolic, musculoskeletal growth, neuronal function and cardiovascular pathways, pathways compatible with the differences in the pathophysiology of adult survivors of SAM. INTERPRETATION: These findings suggest persistent developmental influences on adult physiology in survivors of SAM. Since children who develop marasmus have lower birth weights and after rehabilitation have different intermediary metabolism, these studies provide further support for persistent developmentally-induced phenomena mediated by epigenetic processes affecting both the infant response to acute malnutrition and later life consequences. FUNDING: Supported by a Grant from the Bill and Melinda Gates Foundation (Global Health OPP1066846), Grand Challenge "Discover New Ways to Achieve Healthy Growth." EVIDENCE BEFORE THIS STUDY: Previous research has shown that infants who develop either kwashiorkor or marasmus in response to SAM differ in birth weight and subsequently have different metabolic patterns in both infancy and adulthood. ADDED VALUE OF THIS STUDY: This study demonstrates epigenetic differences in the skeletal muscle of adult survivors of marasmus versus kwashiorkor and these differences are in genes that may underlie the longer-term consequences. IMPLICATIONS OF ALL THE AVAILABLE EVIDENCE: These data are compatible with the different clinical responses to SAM arising from developmentally-induced epigenetic changes laid down largely before birth and provide evidence for the predictive adaptive response model operating in human development.

Efficacy of artemether-lumefantrine in relation to drug exposure in children with and without severe acute malnutrition: an open comparative intervention study in Mali and Niger.

BACKGROUND: Severe acute malnutrition (SAM) affects almost all organs and has been associated with reduced intestinal absorption of medicines. However, very limited information is available on the pharmacokinetic properties of antimalarial drugs in this vulnerable population. We assessed artemether-lumefantrine (AL) clinical efficacy in children with SAM compared to those without. METHODS: Children under 5 years of age with uncomplicated P. falciparum malaria were enrolled between November 2013 and January 2015 in Mali and Niger, one third with uncomplicated SAM and two thirds without. AL was administered under direct observation with a fat intake consisting of ready-to-use therapeutic food (RUTF - Plumpy'Nut®) in SAM children, twice daily during 3 days. Children were followed for 42 days, with PCR-corrected adequate clinical and parasitological response (ACPR) at day 28 as the primary outcome. Lumefantrine concentrations were assessed in a subset of participants at different time points, including systematic measurements on day 7. RESULTS: A total of 399 children (360 in Mali and 39 in Niger) were enrolled. Children with SAM were younger than their non-SAM counterparts (mean 17 vs. 28 months, P < 0.0001). PCR-corrected ACPR was 100 % (95 % CI, 96.8-100 %) in SAM at both day 28 and 42, versus 98.8 % (96.4-99.7 %) at day 28 and 98.3 % (95.6-99.4 %) at day 42 in non-SAM (P = 0.236 and 0.168, respectively). Compared to younger children, children older than 21 months experienced more reinfections and SAM was associated with a greater risk of reinfection until day 28 (adjusted hazard ratio = 2.10 (1.04-4.22), P = 0.038). Day 7 lumefantrine concentrations were significantly lower in SAM than non-SAM (median 251 vs. 365 ng/mL, P = 0.049). CONCLUSIONS: This study shows comparable therapeutic efficacy of AL in children without SAM and in those with SAM when given in combination with RUTF, but a higher risk of reinfection in older children suffering from SAM. This could be associated with poorer exposure to the antimalarials as documented by a lower lumefantrine concentration on day 7. TRIAL REGISTRATION: ClinicalTrials.gov: NCT01958905 , registration date: October 7, 2013.

Impaired Bile Acid Homeostasis in Children with Severe Acute Malnutrition.

OBJECTIVE: Severe acute malnutrition (SAM) is a major cause of mortality in children under 5 years and is associated with hepatic steatosis. Bile acids are synthesized in the liver and participate in dietary fat digestion, regulation of energy expenditure, and immune responses. The aim of this work was to investigate whether SAM is associated with clinically relevant changes in bile acid homeostasis. DESIGN: An initial discovery cohort with 5 healthy controls and 22 SAM-patients was used to identify altered bile acid homeostasis. A follow up cohort of 40 SAM-patients were then studied on admission and 3 days after clinical stabilization to assess recovery in bile acid metabolism. Recruited children were 6-60 months old and admitted for SAM in Malawi. Clinical characteristics, feces and blood were collected on admission and prior to discharge. Bile acids, 7α-hydroxy-4-cholesten-3-one (C4) and FGF-19 were quantified. RESULTS: On admission, total serum bile acids were higher in children with SAM than in healthy controls and glycine-conjugates accounted for most of this accumulation with median and interquartile range (IQR) of 24.6 µmol/L [8.6-47.7] compared to 1.9 µmol/L [1.7-3.3] (p = 0.01) in controls. Total serum bile acid concentrations did not decrease prior to discharge. On admission, fecal conjugated bile acids were lower and secondary bile acids higher at admission compared to pre- discharge, suggesting increased bacterial conversion. FGF19 (Fibroblast growth factor 19), a marker of intestinal bile acid signaling, was higher on admission and was associated with decreased C4 concentrations as a marker of bile acid synthesis. Upon recovery, fecal calprotectin, a marker of intestinal inflammation, was lower. CONCLUSION: SAM is associated with increased serum bile acid levels despite reduced synthesis rates. In SAM, there tends to be increased deconjugation of bile acids and conversion from primary to secondary bile acids, which may contribute to the development of liver disease.