Ascorbic Acid Treatment in Congenital Glucocorticoids and Mineralocorticoids Deficiency Due to NNT Mutation

Overview

Nicotinamide nucleotide transhydrogenase (NNT) mutations cause glucocorticoid and mineralocorticoid deficiencies through decreased detoxification of reactive oxygen species (ROS) in adrenocortical cells. Ascorbic acid is well known by its high antioxidant activity due to the neutralization of free radicals and other reactive oxygen species. Preliminary results of NNT\_p.G200S homozygous fibroblasts' treatment with 10 micro molar L-ascorbic acid shows significant improvement in mitochondrial morphology and in ROS content. The aim of this study is to figure out if ascorbic acid treatment improves the phenotype of NNT patients by reducing ROS in their adrenocortical cells and preventing their apoptosis.

Most cases of familial glucocorticoid and mineralocorticoid deficiency are caused by mutations interrupting steroidogenesis such as 21- hydroxylase deficiency. Recently, nicotinamide nucleotide transhydrogenase (NNT) mutations were found to cause isolated glucocorticoid deficiency or combined mineralocorticoid and glucocorticoid deficiency through decreased detoxification of reactive oxygen species (ROS) in adrenocortical cells. NNT mutation in mice causes also glucose intolerance. Ascorbic acid is an essential water-soluble vitamin with excellent reducing properties, well known by its high antioxidant activity due to the neutralization of free radicals and other reactive oxygen species. This vitamin acts as the first line of defense during oxidative stress in the human body. Ascorbic acid treatment for variant disease (e.g. - cancer, type 2 diabetes, anxiety, depression, asthma and cardiovascular diseases) have been meticulously studies with no major adverse effects. In a previous study, the investigators demonstrated a higher ROS levels, a lower ATP content and a change in mitochondrial morphology in NNT\_p.G200S homozygous fibroblasts compared with control fibroblasts. Preliminary results of NNT\_p.G200S homozygous fibroblasts' treatment with 10 micro molar L-ascorbic acid shows significant improvement in mitochondrial morphology and in ROS content. The aim of this study is to figure out if ascorbic acid treatment improves the phenotype of NNT patients by reducing ROS in their adrenocortical cells and preventing their apoptosis. During the study NNT\_p.G200S homozygous patients (no.-3) will be hospitalised for ACTH and OGTT tests and start ascorbic acid treatment at a doses of 75-80% of the upper limit of allowance according to IOM. ACTH and OGTT will be repeated 6 months later to assess improvement in glucocorticoids production and insulin resistance.