👤 Marçal Vilar

Dysregulation of the melanocortin-4 receptor (MC4R) pathway can lead to severe hyperphagia and early-onset obesity. Symptoms may present before age 6 years, but there is limited clinical data on treatment outcomes in very young children. Setmelanotide, an MC4R agonist, is approved for patients age ≥2 years with rare MC4R pathway disease due to Bardet-Biedl syndrome, pro-opiomelanocortin or proprotein convertase subtilisin/kexin type 1 deficiency or leptin receptor (LEPR) deficiency. This case report describes the use of setmelanotide in a 2-year-old child with hyperphagia and obesity due to LEPR deficiency. The patient presented with early-onset hyperphagia, rapid weight gain, and obesity-associated delays in motor development. Following a medical assessment in May 2021 he was diagnosed with LEPR deficiency. Setmelanotide treatment via subcutaneous injection was initiated in March 2023 (patient age 2 years 4 months) at a dose of 0.5 mg/day, increased to 2.5 mg/day in 0.5 mg increments, and the patient was followed for 23 months. Following treatment initiation, significant clinical improvements were observed, including reductions in hyperphagia, food intake and cravings, and body mass index (BMI). Motor skill function also improved, with the child achieving milestones such as crawling and kneeling. Reported adverse events included skin rash and skin hyperpigmentation. Setmelanotide treatment started in a 2-year-old patient and continued for 23 months led to reductions in hyperphagia and food-seeking behavior, as well as improved motor skill function, BMI, and blood lipids. These findings support the use of setmelanotide in young children with hyperphagia and obesity due to LEPR deficiency. Show less

Raised serum cholesterol concentration is a well-established risk factor in cardiovascular disease. In addition, genetic load may have an indirect influence on cardiovascular risk. Plant-based sterol-supplemented foods are recommended to help reduce the serum low-density lipoprotein cholesterol level. The objective was to analyse the influence of different polymorphisms in hypercholesterolemia patients following a dietary treatment with plant sterols. A randomised double-blind cross-over controlled clinical trial was carried out in 45 people (25 women). Commercial milk, containing 2.24 g of sterols, was ingested daily during a 3-week period, and then the same amount of skim milk, without sterols, was consumed daily during the 3-week placebo phase. Both phases were separated by a washout period of 2 weeks. At the beginning and end of each phase, blood draws were performed. Genes Show less

Ligand-mediated dimerization has emerged as a universal mechanism of growth factor receptor activation. Neurotrophins interact with dimers of the p75 neurotrophin receptor (p75(NTR)), but the mechanism of receptor activation has remained elusive. Here, we show that p75(NTR) forms disulphide-linked dimers independently of neurotrophin binding through the highly conserved Cys(257) in its transmembrane domain. Mutation of Cys(257) abolished neurotrophin-dependent receptor activity but did not affect downstream signaling by the p75(NTR)/NgR/Lingo-1 complex in response to MAG, indicating the existence of distinct, ligand-specific activation mechanisms for p75(NTR). FRET experiments revealed a close association of p75(NTR) intracellular domains that was transiently disrupted by conformational changes induced upon NGF binding. Although mutation of Cys(257) did not alter the oligomeric state of p75(NTR), the mutant receptor was no longer able to propagate conformational changes to the cytoplasmic domain upon ligand binding. We propose that neurotrophins activate p75(NTR) by a mechanism involving rearrangement of disulphide-linked receptor subunits. Show less