Body composition in adults with neurofibromatosis type 1

Souza, Márcio Leandro Ribeiro de; Jansen, Ann Kristine; Martins, Aline Stangherlin; Rodrigues, Luiz Oswaldo Carneiro; Rezende, Nilton Alves de

doi:10.1590/1806-9282.62.09.831

Cited by 15 publications

(19 citation statements)

References 24 publications

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“…Two hypotheses could explain these findings, insulin sensitivity in individuals with NF1 may be mild, and it may not be sufficient to induce obesity or insulin sensitivity that is specific to non-fat tissues. We believe that the characteristics of body composition in NFI patients, demonstrated in other studies (27) and associated with increased adiponectin and lower visfatin and leptin levels, may be related to higher insulin sensitivity found in this group of individuals.…”

Section: Discussionmentioning

confidence: 51%

Increased insulin sensitivity in individuals with neurofibromatosis type 1

Martins¹,

Jansen²,

Rodrigues³

et al. 2018

Archives of Endocrinology and Metabolism

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Objects To compare insulin resistance (IR) and metabolic aspects of patients with neurofibromatosis type 1 (NF1) and individuals without the disease. Subjects and methods Forty patients with NF1 were matched by sex, age, and body mass index (BMI) to 40 controls from the community. Blood samples were collected for biochemical assessment. Homeostasis model assessment adiponectin (HOMA-AD), Homeostasis model assessment insulin resistance (HOMA-IR), and adiponectin/leptin ratio (ALR) were used to identify IR. Results The median HOMA-IR values were similar between the groups. However, the HOMA-AD value was significantly lower and the ALR significantly higher in the NF1 group. Fasting blood glucose (FBG), leptin, and visfatin levels of patients with NF1 were significantly lower, although adiponectin levels were significantly higher than those in the controls. Fasting insulin and blood glucose levels 2 hours after administration of 75 g of dextrose, glycated hemoglobin, and resistin showed no significant differences between groups. The HOMA-AD correlated with BMI, FBG, blood glucose levels 2 hours after administration of 75 g of dextrose, fasting insulin, glycated hemoglobin, adiponectin, leptin, visfatin, ALR, and HOMA-IR. The ALR correlated with BMI leptin, visfatin, and adiponectin. Conclusions Lower levels of FBG, leptin, visfatin, and HOMA-AD, and higher adiponectin levels and ALR may be related to increased insulin sensitivity and lower occurrence of type 2 diabetes mellitus in patients with NF1.

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Section: Discussionmentioning

confidence: 51%

Increased insulin sensitivity in individuals with neurofibromatosis type 1

Martins¹,

Jansen²,

Rodrigues³

et al. 2018

Archives of Endocrinology and Metabolism

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“…Due to the numerous cellular functions of Ras, as well as potential interactions of 33 neurofibromin with other signaling molecules (Ho et Emerging evidence suggests that NF1 regulates cellular and organismal metabolism. NF1 has 40 been associated with short stature, as well as reduced body mass index in males (Koga et al,41 2016; Souza et al, 2016), although the mechanisms underlying these manifestations are 42 unknown. Alterations in certain metabolites have been reported in NF1 patients, though these 43 are sex-specific (Koga et al, 2016).…”

Section: Introduction 22mentioning

confidence: 99%

“…Alterations in certain metabolites have been reported in NF1 patients, though these 43 are sex-specific (Koga et al, 2016). The incidence of diabetes mellitus, deaths from diabetes 44 mellitus, and fasting blood glucose levels are lower in individuals with NF1 than in healthy 45 controls (Martins et al, 2016). Of potential importance for NF1-associated tumorigenesis, loss 46 4 of NF1 increases glycolysis and decreases respiration via Ras/ERK signaling in mitochondria 47 (Masgras et al, 2017).…”

Section: Introduction 22mentioning

confidence: 99%

Neurofibromin regulates metabolic rate via neuronal mechanisms in Drosophila

Botero

Stahl

Grenci

et al. 2019

Preprint

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1Neurofibromatosis type 1 (NF1) is a genetic disorder predisposing patients to a range of 2 features, the most characteristic of which include areas of abnormal skin pigmentation and 3 benign tumors associated with peripheral nerves, termed neurofibromas. Less common, but 4 more serious symptoms also include malignant peripheral nerve sheath tumors, other 5 malignancies, and learning disabilities. The NF1 gene encodes neurofibromin, a large protein 6 that functions as a negative regulator of Ras signaling and mediates pleiotropic cellular and 7 organismal function. Recent evidence suggests NF1 may regulate metabolism, though the 8 mechanisms are unknown. Here we show that the Drosophila ortholog of NF1, dNf1 regulates 9 metabolic homeostasis in fruit flies by functioning within a discrete brain circuit. Loss of dNf1 10 increases metabolic rate and feeding, enhances starvation susceptibility, and decreases lipid 11 stores while increasing lipid turnover rate. The increase in metabolic rate is independent of 12 locomotor activity (grooming), and maps to a subset of neurons in the ventral nervous system. 13The feeding and metabolic rate effects are due to loss of dNf1 in the same set of neurons, 14suggesting that increased feeding may be a compensatory effect driven by the increase in 15 metabolic rate and lipid turnover. Finally, we show that the Ras GAP-related domain of 16 neurofibromin is required for normal metabolism, demonstrating that Ras signaling downstream 17 of dNf1 mediates the metabolic effects. These data demonstrate that dNf1 regulates metabolic 18 rate via neuronal mechanisms, suggest that cellular and systemic metabolic alterations may 19 represent a pathophysiological mechanism in NF1, and provide a platform for investigating the 20 cellular role of neurofibromin in metabolic homeostasis. 21

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“…There was no evidence of infection or cardiovascular dysfunction that could explain the acute death. Recent studies show that NF1 patients have a high prevalence of being underweight with short stature accompanied by lower BMI (32)(33)(34). Further studies need to be conducted to assess body composition within NF1 patients that could be underweight due to a decrease in body fat and a similar underlying metabolic condition as compared to this systemic knockout Nf1 model.…”

Section: Discussionmentioning

confidence: 99%