Search

The melanocortin-4 receptor (MC4R) is a G protein-coupled receptor (GPCR) that is expressed in several brain locations encompassing the hypothalamus and the brainstem, where the receptor controls several body functions, including metabolism. In a well-defined pathway to decrease appetite, hypothalamic proopiomelanocortin (POMC) neurons localized in the arcuate nucleus (Arc) project to MC4R neurons in the paraventricular nuclei (PVN) to release the natural MC4R agonist α-melanocyte-stimulating hormone (α-MSH). Arc neurons also project excitatory glutamatergic fibers to the MC4R neurons in the PVN for a fast synaptic transmission to regulate a satiety pathway potentiated by α-MSH. By using super-resolution microscopy, we found that in hypothalamic neurons in a primary culture, postsynaptic density protein 95 (PSD95) colocalizes with GluN1, a subunit of the ionotropic N-methyl-D-aspartate receptor (NMDAR). Thus, hypothalamic neurons form excitatory postsynaptic specializations. To study the MC4R distribution at these sites, tagged HA-MC4R under the synapsin promoter was expressed in neurons by adeno-associated virus (AAV) gene transduction. HA-MC4R immunofluorescence peaked at the center and in proximity to the PSD95- and NMDAR-expressing sites. These data provide morphological evidence that MC4R localizes together with glutamate receptors at postsynaptic and peri-postsynaptic sites. [ABSTRACT FROM AUTHOR]

Background Lipid-based nutrient supplements (LNS) and corn-soy blends (CSBs) with varying soy and milk content are used in treatment of moderate acute malnutrition (MAM). We assessed the impact of these supplements on child development. Methods and findings We conducted a randomised 2 x 2 x 3 factorial trial to assess the effectiveness of 12 weeks' supplementation with LNS or CSB, with either soy isolate or dehulled soy, and either 0%, 20%, or 50% of protein from milk, on child development among 6-23-month-old children with MAM. Recruitment took place at 5 health centres in Province du Passoré, Burkina Faso between September 2013 and August 2014. The study was fully blinded with respect to soy quality and milk content, while study participants were not blinded with respect to matrix. This analysis presents secondary trial outcomes: Gross motor, fine motor, and language development were assessed using the Malawi Development Assessment Tool (MDAT). Of 1,609 children enrolled, 54.7% were girls, and median age was 11.3 months (interquartile range [IQR] 8.2-16.0). Twelve weeks follow-up was completed by 1,548 (96.2%), and 24 weeks follow-up was completed by 1,503 (93.4%); follow-up was similar between randomised groups. During the study, 4 children died, and 102 children developed severe acute malnutrition (SAM). There was no difference in adverse events between randomised groups. At 12 weeks, the mean MDAT z-scores in the whole cohort had increased by 0.33 (95% CI: 0.28, 0.37), p < 0.001 for gross motor; 0.26 (0.20, 0.31), p < 0.001 for fine motor; and 0.14 (0.09, 0.20), p < 0.001 for language development. Children had larger improvement in language z-scores if receiving supplements with milk (20%: 0.09 [-0.01, 0.19], p = 0.08 and 50%: 0.11 [0.01, 0.21], p = 0.02), although the difference only reached statistical significance for 50% milk. Post hoc analyses suggested that this effect was specific to boys (interaction p = 0.02). The fine motor z-scores were also improved in children receiving milk, but only when 20% milk was added to CSB (0.18 [0.03, 0.33], p = 0.02). Soy isolate over dehulled soy increased language z-scores by 0.07 (-0.01, 0.15), p = 0.10, although not statistically significant. Post hoc analyses suggested that LNS benefited gross motor development among boys more than did CSB (interaction p = 0.04). Differences between supplement groups did not persist at 24 weeks, but MDAT z-scores continued to increase post-supplementation. The lack of an unsupplemented control group limits us from determining the overall effects of nutritional supplementation for children with MAM. Conclusions In this study, we found that child development improved during and after supplementation for treatment of MAM. Milk protein was beneficial for language and fine motor development, while suggested benefits related to soy quality and supplement matrix merit further investigation. Supplement-specific effects were not found post-intervention, but z-scores continued to improve, suggesting a sustained overall effect of supplementation. Trial registration ISRCTN42569496, Author(s): Mette F. Olsen 1,*, Ann-Sophie Iuel-Brockdorff 1, Charles W. Yaméogo 1,2, Bernardette Cichon 1, Christian Fabiansen 1, Suzanne Filteau 3, Kevin Phelan 4, Albertine Ouédraogo 4, Kim F. Michaelsen [...]

One feature of high-fat diet-induced neurodegeneration in the hypothalamus is an increased level of palmitate, which is associated with endoplasmic reticulum (ER) stress, loss of CoxIV, mitochondrial fragmentation, and decreased abundance of MC4R. To determine whether antidiabetic drugs protect against ER and/or mitochondrial dysfunction by lipid stress, hypothalamic neurons derived from pre-adult mice and neuronal Neuro2A cells were exposed to elevated palmitate. In the hypothalamic neurons, palmitate exposure increased expression of ER resident proteins, including that of SERCA2, indicating ER stress. Liraglutide reverted such altered ER proteostasis, while metformin only normalized SERCA2 expression. In Neuro2A cells liraglutide, but not metformin, also blunted dilation of the ER induced by palmitate treatment, and enhanced abundance and expression of MC4R at the cell surface. Thus, liraglutide counteracts, more effectively than metformin, altered ER proteostasis, morphology, and folding capacity in neurons exposed to fat. In palmitate-treated hypothalamic neurons, mitochondrial fragmentation took place together with loss of CoxIV and decreased mitochondrial membrane potential (MMP). Metformin, but not liraglutide, reverted mitochondrial fragmentation, and both liraglutide and metformin did not protect against either loss of CoxIV abundance or MMP. Thus, ER recovery from lipid stress can take place in hypothalamic neurons in the absence of recovered mitochondrial homeostasis. [ABSTRACT FROM AUTHOR]

Access to treatment for acute malnutrition remains a challenge, in part due to the fragmentation of treatment programmes based on case severity. This paper evaluates utilization patterns, outcomes and associated costs for treating acute malnutrition cases among a cohort of children in Burkina Faso. This study is a secondary analysis of a proof‐of‐concept trial, called Optimizing treatment for acute Malnutrition (OptiMA), conducted in Burkina Faso in 2016. A total of 4958 eligible children whose mid‐upper arm circumference (MUAC) was less than 125 mm or with oedema were followed weekly and given ready‐to‐use therapeutic foods (RUTF). We evaluated the service utilization and outcomes among patients and estimated resource use and variable cost per patient, and examined factors driving variation in resource use. Children with lower initial MUAC level grew faster but required more time to recover than those with higher initial MUAC level. They also had higher rates of death, default and nonresponse. The simplified OptiMA approach for treating acute malnutrition achieved high rates of recovery overall (84%), especially among less severe cases, with modest quantities of RUTF. The average overall variable cost per child admitted was US$38.0 (SD: 20.5) half of which was accounted for by the cost of RUTF. Cost per recovered case was correlated with case severity, ranging from US$35.1 to US$132.8. If simplified integrated programmes using severity‐based RUTF dosing can increase access to treatment at earlier, less severe stages of acute malnutrition, they can help avoid more serious and costlier cases. Key messages: This paper evaluates utilization patterns, outcomes, and associated costs for treating acute malnutrition cases among a cohort of children in Burkina Faso.Children with lower initial mid upper arm circumference (MUAC) level grew faster but required more time to recover than those with higher initial MUAC level.The average cost per child admitted was US$38.0 half of which was accounted for by the cost of ready to use therapeutic foods (RUTF).If simplified programs can increase access to treatment at earlier, less severe stages of acute malnutrition, they can help avoid more serious and costlier cases. [ABSTRACT FROM AUTHOR]