A Hypomethylating Ketogenic Diet in Apolipoprotein E-Deficient Mice: A Pilot Study on Vascular Effects and Specific Epigenetic Changes

Hyperhomocysteneinemia (HHcy) is common in the general population and is a risk factor for atherosclerosis by mechanisms that are still elusive. A hypomethylated status of epigenetically relevant targets may contribute to the vascular toxicity associated with HHcy. Ketogenic diets (KD) are diets with a severely restricted amount of carbohydrates that are being widely used, mainly for weight-loss purposes. However, studies associating nutritional ketosis and HHcy are lacking. This pilot study investigates the effects of mild HHcy induced by nutritional manipulation of the methionine metabolism in the absence of dietary carbohydrates on disease progression and specific epigenetic changes in the apolipoprotein-E deficient (apoE–/–) mouse model. ApoE–/– mice were either fed a KD, a diet with the same macronutrient composition but low in methyl donors (low methyl KD, LMKD), or control diet. After 4, 8 or 12 weeks plasma was collected for the quantification of: (1) nutritional ketosis, (i.e., the ketone body beta-hydroxybutyrate using a colorimetric assay); (2) homocysteine by HPLC; (3) the methylating potential S-adenosylmethionine to S-adenosylhomocysteine ratio (AdoHcy/AdoMet) by LC-MS/MS; and (4) the inflammatory cytokine monocyte chemoattractant protein 1 (MCP1) by ELISA. After 12 weeks, aortas were collected to assess: (1) the vascular AdoHcy/AdoMet ratio; (2) the volume of atherosclerotic lesions by high-field magnetic resonance imaging (14T-MRI); and (3) the content of specific epigenetic tags (H3K27me3 and H3K27ac) by immunofluorescence. The results confirmed the presence of nutritional ketosis in KD and LMKD mice but not in the control mice. As expected, mild HHcy was only detected in the LMKD-fed mice. Significantly decreased MCP1 plasma levels and plaque burden were observed in control mice versus the other two groups, together with an increased content of one of the investigated epigenetic tags (H3K27me3) but not of the other (H3K27ac). Moreover, we are unable to detect any significant differences at the p < 0.05 level for MCP1 plasma levels, vascular AdoMet:AdoHcy ratio levels, plaque burden, and specific epigenetic content between the latter two groups. Nevertheless, the systemic methylating index was significantly decreased in LMKD mice versus the other two groups, reinforcing the possibility that the levels of accumulated homocysteine were insufficient to affect vascular transmethylation reactions. Further studies addressing nutritional ketosis in the presence of mild HHcy should use a higher number of animals and are warranted to confirm these preliminary observations.

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Diet-Induced Mild Hyperhomocysteinemia in Mice Fed a Ketogenic Diet Does Not Alter the Development of Atherosclerosis nor Specific Epigenetic Content

Current Developments in Nutrition ◽

10.1093/cdn/nzab050_020 ◽

2021 ◽

Vol 5 (Supplement_2) ◽

pp. 953-953

Author(s):

Courtney Whalen ◽

Sean Gullette ◽

Floyd Mattie ◽

Thomas Neuberger ◽

A Catharin Ross ◽

...

Keyword(s):

Colorimetric Assay ◽

Plaque Burden ◽

Vascular Toxicity ◽

Methyl Donors ◽

Atherosclerosis Progression ◽

Methylation Index ◽

Funding Sources ◽

Ketogenic Diets ◽

Mild Hyperhomocysteinemia ◽

Beta Hydroxybutyrate

Abstract Objectives Elevated plasma homocysteine (Hcy), or hyperhomocysteinemia (HHcy), is a risk factor for atherosclerosis by mechanisms still elusive. A possibility includes the alteration of specific epigenetic tags at lysine 27 of histone H3 (H3K27) due to hypomethylating stress. Similarly, ketogenic diets (KD), or very-low carbohydrate diets, which stimulate ketosis, and may also affect the epigenetic content on the H3K27 residue. Studies connecting the effects of dietary ketosis, mild HHcy, and specific epigenetic dysregulation are lacking. We hypothesize that diet-induced HHcy and ketosis will induce H3K27 hypomethylation combined with increased acetylation to produce a pro-atherogenic phenotype. Methods Seven-week-old male apoe−/− (apolipoprotein E-deficient) mice, a model for human atherosclerosis, were fed ad libitum a KD (in %kcal: fat, 81; carbohydrate, 1; protein, 18; n = 4–6) or HHcy-KD (same macronutrients, with added methionine and reduced methyl donors; n = 4). After 4, 8 and 12 wk of diet treatment, plasma was collected to quantify ketosis via beta-hydroxybutyrate levels (OH-But) by a colorimetric assay, and measure Hcy by HPLC. At the endpoint, mice were euthanized and aortas were collected for quantification of the vascular methylation index, S-adenosylmethionine to S-adenosylHcy ratio by LC-MS-MS; 3-D analysis of the atherosclerotic plaque burden by magnetic resonance imaging; and quantification of the epigenetic tags H3K27me3 and H3K27ac using immunohistochemistry. Results A sustained ketosis was detected through elevated OH-But levels in both KD and HHcy-KD mice. HHcy was mildly but significantly (P < 0.05) elevated in HHcy-KD-mice compared to KD-mice after 4 wk (19.5 ± 2.3 vs 4.5 ± 0.6 µM) and 12 wk (17.2 ± 2.1 vs 4.4 ± 0.9 µM). Nevertheless, no significant differences were observed in aortic methylation index, plaque accumulation, or content of the H3K27me3 or H3K27ac epigenetic tags between the two groups of mice. Conclusions While mild HHcy was achieved in HHcy-KD mice, this phenotype failed to induce vascular hypomethylation, atherosclerosis progression or specific epigenetic dysregulation, suggesting that a more severe Hcy accumulation may be necessary to cause vascular toxicity and specific epigenetic dysregulation. Funding Sources Huck Institutes of the Life Sciences

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NT-PROBNP AND THE CUT-OFF VALUE IN CARDIOVASCULAR DISEASES

Journal of Medicine and Pharmacy ◽

10.34071/jmp.2011.5.1 ◽

2011 ◽

pp. 5-12

Author(s):

Anh Tien Hoang ◽

Van Minh Huynh ◽

Khanh Hoang ◽

Huu Dang Tran ◽

Viet An Tran

Keyword(s):

Heart Failure ◽

Cardiovascular Disease ◽

Pilot Study ◽

Cardiovascular Diseases ◽

Clinical Application ◽

European Society ◽

The Other ◽

Cardiac Marker ◽

Cardiac Biomarker ◽

European Society Of Cardiology

NT-ProBNP is a high value cardiac biomarker and widely applies in many cardiovascular diseases. The evaluation of concentration of NT-ProBNP needs the concern about age, gender, obesity and especially we need each cut-off point for each cause of cardiovascular disease in evaluation and clinical application. Because NT-ProBNP is a new cardiac marker and has been researched in 5 recent years, the cut-off of NT-ProBNP is still being studied for the clinical application in cardiovascular diseases. Only the cut-off of NT-ProBNP in diagnosis heart failure was guided by European Society of Cardiology. The meaning of introduce cut-off value of value plays an role as pilot study for the other relate study and brings the NT-ProBNP closely approach to clinical application.

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Atheromatosis Extent in Coronary Artery Disease is not Correlated with Apolipoprotein-E Polymorphism and its Plasma Levels, but Associated with Cognitive Decline

Current Alzheimer Research ◽

10.2174/1567210204558632050 ◽

2010 ◽

Vol 999 (999) ◽

pp. 1-8 ◽

Cited By ~ 1

Author(s):

Luciana Moreira Lima ◽

Maria das Gracas Carvalho ◽

Claudia Natalia Ferreira ◽

Ana Paula Fernandes ◽

Cirilo Pereira da Fonseca Neto ◽

...

Keyword(s):

Coronary Artery Disease ◽

Coronary Artery ◽

Cognitive Decline ◽

Apolipoprotein E ◽

Plasma Levels ◽

Apolipoprotein E Polymorphism ◽

Artery Disease

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A Novel Dietary Intervention Reduces Circulatory Branched-Chain Amino Acids by 50%: A Pilot Study of Relevance for Obesity and Diabetes

Nutrients ◽

10.3390/nu13010095 ◽

2020 ◽

Vol 13 (1) ◽

pp. 95

Author(s):

Imran Ramzan ◽

Moira Taylor ◽

Beth Phillips ◽

Daniel Wilkinson ◽

Kenneth Smith ◽

...

Keyword(s):

Amino Acids ◽

Pilot Study ◽

Dietary Intervention ◽

Control Diet ◽

Branched Chain Amino Acids ◽

Model Assessment ◽

Dietary Intakes ◽

Restricted Diet ◽

Obesity And Diabetes ◽

Branched Chain

Elevated circulating branched-chain amino acids (BCAAs; isoleucine, leucine, and valine) are associated with obesity and type 2 diabetes (T2D). Reducing circulatory BCAAs by dietary restriction was suggested to mitigate these risks in rodent models, but this is a challenging paradigm to deliver in humans. We aimed to design and assess the feasibility of a diet aimed at reducing circulating BCAA concentrations in humans, while maintaining energy balance and overall energy/protein intake. Twelve healthy individuals were assigned to either a 7-day BCAA-restricted diet or a 7-day control diet. Diets were iso-nitrogenous and iso-caloric, with only BCAA levels differing between the two. The BCAA-restricted diet significantly reduced circulating BCAA concentrations by ~50% i.e., baseline 437 ± 60 to 217 ± 40 µmol/L (p < 0.005). Individually, both valine (245 ± 33 to 105 ± 23 µmol/L; p < 0.0001), and leucine (130 ± 20 to 75 ± 13 µmol/L; p < 0.05), decreased significantly in response to the BCAA-restricted diet. The BCAA-restricted diet marginally lowered Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) levels: baseline 1.5 ± 0.2 to 1.0 ± 0.1; (p = 0.096). We successfully lowered circulating BCAAs by 50% while maintaining iso-nitrogenous, iso-caloric dietary intakes, and while meeting the recommended daily allowances (RDA) for protein requirements. The present pilot study represents a novel dietary means by which to reduce BCAA, and as such, provides a blueprint for a potential dietary therapeutic in obesity/diabetes.

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Preferred versus Nonpreferred Treatment, and Self-Control Training versus Determination Raising as Treatments of Obesity: A Pilot Study

Psychological Reports ◽

10.2466/pr0.1976.38.1.191 ◽

1976 ◽

Vol 38 (1) ◽

pp. 191-198 ◽

Cited By ~ 15

Author(s):

D. C. Murray

Keyword(s):

Weight Loss ◽

Pilot Study ◽

Treatment Group ◽

Self Control ◽

The Other ◽

Significant Weight Loss ◽

Overweight Women

Of 12 overweight women half received 10 wk. of self-control training and the rest received an equal period aimed at increasing determination to lose weight. Half of each treatment group had expressed a preference for the type of treatment they received and half for the other type of treatment. Both groups lost a statistically significant amount of weight, and at a 3-mo. follow-up there was still a significant weight loss. Follow-up at 6 mo. on 9 of the 12 original subjects indicated both groups regained much of their lost weight. There was no evidence that either type of treatment or receiving one's preferred type of treatment was related to weight loss.

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THE EFFECT OF EXOGENOUS PROGESTAGEN ON THE LEVELS OF FREE OESTROGEN IN THE OVARIAN VEIN PLASMA OF THE EWE

Journal of Endocrinology ◽

10.1677/joe.0.0480485 ◽

1970 ◽

Vol 48 (4) ◽

pp. 485-496 ◽

Cited By ~ 7

Author(s):

J. F. SMITH ◽

T. J. ROBINSON

Keyword(s):

Plasma Levels ◽

Similar Pattern ◽

Peak Level ◽

The Other ◽

Ovarian Vein ◽

Active Ovary ◽

The Mean ◽

Significant Change

SUMMARY The levels of free oestrogen (oestrone and oestradiol-17β) in plasma in the ovarian vein were determined in three groups, each of 27 ewes, at nine intervals at about the time of oestrus. One group had a normal oestrus while the other two had been treated for 16 days with intravaginal sponges containing either 10 or 30 mg of a synthetic progestagen (Cronolone, Searle). In untreated ewes, the mean level (corrected) of oestradiol-17β in plasma from the active ovary rose from 25·3 ng/100 ml at −48 h to a peak of 91·6 ng/100 ml at 0 h (onset of oestrus) and then fell. There was evidence of biphasic production. The mean level of oestrone was relatively high (13·0 ng/100 ml) at −48 h; it fell to 2·0 ng/100 ml between −36 and −24 h and then rose again to 9·4 ng/100 ml at + 12 h. There was no significant change, with time, in the plasma levels of either oestrogen from the non-active ovary. The total amounts of oestradiol-17β and of oestrone produced from both ovaries at an oestrous period were estimated to average 9·7 and 2·4 μg. In treated ewes, a similar pattern of production of oestradiol-17β was shown by the ewes treated with 30 mg Cronolone. That of ewes treated with 10 mg differed (P < 0·01). Peak level was reached at an earlier stage, relative to the onset of oestrus, and it declined more rapidly, the total amount of oestrogen produced (oestrone + oestradiol-17β) was less (10 mg Cronolone, 8·6 μg; 30 mg Cronolone, 12·1 μg; normal oestrus, 12·1 μg), and there was no biphasic production.

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Abstract 1122‐000172: High Resolution Vessel Wall Imaging and Cerebrovascular Plaques: Comparison with DSA, MRA, and CTA

Stroke: Vascular and Interventional Neurology ◽

10.1161/svin.01.suppl_1.000172 ◽

2021 ◽

Vol 1 (S1) ◽

Author(s):

Rami Fakih ◽

Alberto Miller ◽

Ashrita Raghuram ◽

Sebastian Herrera ◽

Sedat Kandemirli ◽

...

Keyword(s):

Vessel Wall ◽

The Other ◽

Imaging Modalities ◽

Plaque Burden ◽

Rater Agreement ◽

Cross Sectional ◽

Tof Mra ◽

Plaque Detection ◽

Wall Imaging

Introduction : Current imaging modalities might underestimate the presence and severity of intracranial atherosclerosis (ICAD). High resolution vessel wall imaging (HR‐VWI) MRI emerged as a powerful tool to diagnose plaques not detected on routine imaging. We aim to compare different imaging modalities (HR‐VWI MRI; digital subtraction angiogram (DSA); Time‐of‐flight (TOF) MRA; and CTA) in the identification and characterization of intracranial atherosclerotic culprit plaques. Methods : Patients diagnosed with ICAD were prospectively imaged with HR‐VWI MRI. Culprit plaques were identified based on the likelihood of causing the stroke. Using cross‐sectional images of intracranial vessels, regions of interest (ROI) were delineated. Then, diameters and ROI areas were measured for the purpose of calculating the following variables: degree of stenosis (DS) at the plaque level, plaque burden (PB), and remodeling index (RI). Additional imaging modalities (DSA, TOF MRA, and CTA) were identified retrospectively for each patient. The sensitivity of detecting a culprit plaque as well as the correlations between the different variables were analyzed for each modality. Linear regression analysis was used to determine the association of DS with PB and RI. Interobserver agreement on the determination of a culprit plaque on every imaging modality was evaluated. Results : A total of 44 patients who underwent HR‐VWI had ICAD and were included in the final analysis. Of those, 34 had CTA, 18 had TOF‐MRA, and 18 had DSA. Using HR‐VWI as gold standard, the sensitivity for culprit plaque detection was 88% for DSA, 78% for TOF MRA, and 76% for CTA. We found no difference between the DS in all four modalities using measured cross‐sectional diameters, but difference was found when measuring ROI areas to calculate DS. There was a significant positive correlation between PB and DS on HR‐VWI MRI (p<0.001), but not on the DSA (p = 0.168), MRA (p = 0.144), or CTA (p = 0.253), and a significant negative correlation between RI and DS on HR‐VWI MRI (p = 0.003), but not on DSA (p = 0.783), MRA (p = 0.405), or CTA (p = 0.751). PB and RI predicted the degrees of stenosis on HR‐VWI, but not on the other modalities. There was good inter‐rater agreement for culprit plaque detection on HR‐VWI (k = 0.48, p = 0.001), but no agreement was found on the other modalities. Conclusions : HR‐VWI MRI can locate otherwise undetectable plaques on conventional imaging through the ability to measure plaque burden, an essential component for characterization of plaques severity and a strong predictor of stenosis. HR‐VWI also showed more accurate measurements of degree of stenosis through measurement of ROI areas, and had good inter‐rater agreement for accurate plaque detection, compared to DSA, MRA, and CTA.

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