Isoenergetic Feeding of Low Carbohydrate-High Fat Diets Does Not Increase Brown Adipose Tissue Thermogenic Capacity in Rats

Low-carbohydrate, high-fat (LC-HF) diets are popular for inducing weight loss in overweighed adults. Adaptive thermogenesis increased by specific effects of macronutrients on energy expenditure has been postulated to induce this weight loss. We studied brown adipose tissue (BAT) morphology and function following exposure to different LC-HF diets

PRKACA Somatic Mutations Are Rare Findings in Aldosterone-Producing Adenomas

CONTEXT Somatic mutations have been found causative for endocrine autonomy in aldosterone-producing adenomas (APAs). Whereas mutations of PRKACA (catalytic subunit of protein kinase A) have been identified in cortisol-producing adenomas, the presence of PRKACA variants in APAs is unknown, especially in those that display cosecretion of cortisol. OBJECTIVE The objective of the study was to investigate PRKACA somatic variants identified in APA cases. DESIGN Identification of PRKACA somatic variants in APAs by whole-exome sequencing followed by in vitro analysis of the enzymatic activity of PRKACA variants and functional characterization by double immunofluorescence of CYP11B2 and CYP11B1 expression in the corresponding tumor tissues. SETTING AND PATIENTS APA tissues were collected from 122 patients who underwent unilateral adrenalectomy for primary aldosteronism between 2005 and 2015 at a single institution. RESULTS PRKACA somatic mutations were identified in two APA cases (1.6%). One APA carried a newly identified p.His88Asp variant, whereas in a second case, a p.Leu206Arg mutation was found, previously described only in cortisol-producing adenomas with overt Cushing's syndrome. Functional analysis showed that the p.His88Asp variant was not associated with gain of function. Although CYP11B2 was strongly expressed in the p.His88Asp-mutated APA, the p.Leu206Arg carrying APA predominantly expressed CYP11B1. Accordingly, biochemical Cushing's syndrome was present only in the patient with the p.Leu206Arg mutation. After adrenalectomy, both patients improved with a reduced number of antihypertensive medications and normalized serum potassium levels. CONCLUSIONS We describe for the first time PRKACA mutations as rare findings associated with unilateral primary aldosteronism. As cortisol cosecretion occurs in a subgroup of APAs, other molecular mechanisms are likely to exist

Weight curves of rats on the control diet (circles, fed ad libitum), compared to the three experimental diets (iso-energetic pair feeding): low-carbohydrate high-fat, low-protein diet (LC-HF-LP; squares), low-carbohydrate high-fat, normal-protein diet (LC-HF-NP; upward triangles) or high fat diet (downward triangles); p<0.0005, repeated measurements ANOVA.

<p>The cumulative average weight gain for each group during the four week feeding period is given in the insert, analyzed by global one-way ANOVA and Dunnett tests for pairwise comparison vs. control: * p<0.05, *** p<0.001. Data are shown as means±SEM; n = 7 animals/group.</p

Respirometry.

<p>Measurement of mitochondrial oxygen consumption using microplate based extracellular flux analyzer in tissues from rats fed the control or experimental diets (LC-HF-LP, LC-HF-NP). A: brown adipocyte mitochondria. B: muscle mitochondria. Stage II, basal; stage III, ADP; stage IVo, oligomycin. N = 3/group.</p

Quantitative real time PCR in iBAT following control or experimental diets (LC-HF-LP, LC-HF-NP, high fat).

<p>ADRB3: β3 adrenergic receptor. Gene expression was normalized to 18 S rRNA. Data are shown as means±SEM; n = 7/group; analyzed by global one-way ANOVA and by Dunnett tests for pairwise comparison vs. control. * p<0.05, ** p<0.01 vs. control.</p

In-vivo measurement of maximal adaptive thermogenic capacity in rats fed the control or experimental diets (LC-HF-LP, LC-HF-NP, high fat).

<p>A: respiratory quotient after feeding control or experimental diets for 4 weeks: basal and following norepinephrine injection. B: Basal and norepinephrine stimulated energy expenditure (EE), expressed as kcal/h/kg BW^0.75. The time points 0 min and 36 min are not given, as cages had to be opened for animal handling and measures of RQ and EE are not reliable at these time points. The insert shows the mean EE of timepoints 77, 84 and 91 min. Data are shown as means±SEM; n = 7 (control), 6 (LC-HF-LP), 5 (LC-HF-NP), 7 (high fat). Statistical analysis was performed on the average of three time points at baseline and during the plateau phase after NE injection, respectively, using global one-way ANOVA and Dunnett tests for pairwise comparison vs. control.</p

Weight of interscapular brown adipose tissue (iBAT) in rats fed control or experimental diets (LC-HF-LP, LC-HF-NP, high fat).

<p>A: total weight (absolute); B: percentage of body weight (relative). Data are shown as means±SEM, n = 7/group; analyzed by global one-way ANOVA and Dunnett tests for pairwise comparison vs. control. * p<0.05, ** p<0.01 vs. control.</p

Body core temperature in rats fed control or experimental diets (LC-HF-LP, LC-HF-NP, high fat).

<p>A: morning, B: evening. Data are shown as means±SEM; n = 7/group; analyzed by global one-way ANOVA and by Dunnett tests for pairwise comparison vs. control.</p

Primer sequences (5′-3′).

<p>Primer sequences (5′-3′).</p

Monogenic Early-Onset Lymphoproliferation and Autoimmunity: The Natural History of STAT3 GOF Syndrome.

Background In 2014, germline signal transducer and activator of transcription (STAT) 3 gain-of-function (GOF) mutations were first described to cause a novel multisystem disease of early-onset lymphoproliferation and autoimmunity. Objective This pivotal cohort study defines the scope, natural history, treatment, and overall survival of a large global cohort of patients with pathogenic STAT3 GOF variants. Methods We identified 191 patients from 33 countries with 72 unique mutations. Inclusion criteria included symptoms of immune dysregulation and a biochemically confirmed germline heterozygous GOF variant in STAT3. Results Overall survival was 88%, median age at onset of symptoms was 2.3 years, and median age at diagnosis was 12 years. Immune dysregulatory features were present in all patients: lymphoproliferation was the most common manifestation (73%); increased frequencies of double-negative (CD4−CD8−) T cells were found in 83% of patients tested. Autoimmune cytopenias were the second most common clinical manifestation (67%), followed by growth delay, enteropathy, skin disease, pulmonary disease, endocrinopathy, arthritis, autoimmune hepatitis, neurologic disease, vasculopathy, renal disease, and malignancy. Infections were reported in 72% of the cohort. A cellular and humoral immunodeficiency was observed in 37% and 51% of patients, respectively. Clinical symptoms dramatically improved in patients treated with JAK inhibitors, while a variety of other immunomodulatory treatment modalities were less efficacious. Thus far, 23 patients have undergone bone marrow transplantation, with a 62% survival rate. Conclusion : STAT3 GOF patients present with a wide array of immune-mediated disease including lymphoproliferation, autoimmune cytopenias, and multisystem autoimmunity. Patient care tends to be siloed, without a clear treatment strategy. Thus, early identification and prompt treatment implementation are lifesaving for STAT3 GOF syndrome. Key word