Effects of a maternal high-fat diet on adipose tissue in murine offspring: A systematic review and meta-analysis

The aim of this systematic review and meta-analysis was to analyze the influence of a maternal and/or offspring high-fat diet (HFD) on the morphology of the offspring adipocytes and amount of food and energy consumption. The search was conducted through Pubmed, EMBASE, and Web of Science databases up to October 31st, 2021. The outcomes were extracted and pooled as a standardized mean difference with random effect models. 5,004 articles were found in the databases. Of these, only 31 were selected for this systematic review and 21 were included in the meta-analysis. A large discrepancy in the percentage of fat composing the HFD (from 14% to 62% fat content) was observed. Considering the increase of adipose tissue by hyperplasia (cell number increase) and hypertrophy (cell size increase) in HFD models, the meta-analysis showed that excessive consumption of a maternal HFD influences the development of visceral white adipose tissue in offspring, related to adipocyte hypertrophy, regardless of their HFD or control diet consumption. Upon following a long-term HFD, hyperplasia was confirmed in the offspring. When analyzing the secondary outcome in terms of the amount of food and energy consumed, there was an increase of caloric intake in the offspring fed with HFD whose mothers consumed HFD. Furthermore, the adipocyte hypertrophy in different regions of the adipose tissue is related to the sex of the pups. Thus, the adipose tissue obesity phenotypes in offspring are programmed by maternal consumption of a high-fat diet, independent of postnatal diet.

Effects of aerobic exercise training and açai supplementation on cardiac structure and function in rats submitted to a high-fat diet

This study evaluated the effect of aerobic exercise training (AET) and supplementation with açai on cardiac structure and function in rats submitted to a high-fat diet. Two-month old Fischer male rats were divided into 5 groups: Control (C), High-fat Diet (H), High-fat Diet + Açai (HA), High-fat Diet + AET (HT), High-fat Diet + Açai + AET (HAT). The high-fat diet had 21.8% lard and 1% cholesterol (H and HT), or supplemented with 1% lyophilized açai pulp (HA and HAT). The HT and HAT groups performed AET on a treadmill (5 days/week, 1 h/day, 60% of the maximum running speed) for 8 weeks. Exercise tolerance test were performed, and adiposity index calculated. After euthanasia, the left ventricle (LV) was dissected and processed for histological, single myocyte intracellular calcium ([Ca²⁺]_i) transient and contractility, oxidative stress and gene expression analysis. AET improved running capacity and reduced the adiposity index. Both AET and açai supplementation inhibited the increase in the LV collagen content, the deleterious effects on the [Ca²⁺]_i transient and contractility in cardiomyocytes and the increment in oxidative stress, caused by the consumption of a high-fat diet. Aerobic exercise training and açai supplementation can mitigate damage caused by high-fat diet in cardiac structure and function, though the combination of treatments had no additional effects.

Diets with different lipid contents do not modify the neuronal membrane lipid raft profile in a scrapie murine model

In Transmissible Spongiform Encephalopathies (TSEs), the localization of the prion protein in the neuronal membrane lipid rafts (LR) seems to play a role in sustaining the protein misfolding. Changes in membrane properties, due to altered lipid composition, affect their organization and interaction between lipids and protein therein, and consequently also membrane resident protein functionality; dietary polyunsaturated fatty acids (PUFAs), gangliosides and cholesterol seem to influence these processes.

AIMS

In this work, the influence of administration of different feed, able to change the composition of lipid membrane, on the clinical progression of prion disease was studied.

MAIN METHODS

The activity of three diets (hyperlipidic with 6% fats; hypolipidic with 0.1% fats; and purified with 4% fats) was tested in CD1 mouse model experimentally infected with RML scrapie strain. Presence and distribution of typical central nervous system (CNS) lesions and deposits of PrP(sc) were evaluated by histopathological analysis and immunohistochemistry. Analysis of lipids was performed in homogenate and insoluble brain fraction of the neuronal membrane rich in LR.

KEY FINDINGS

Results show that a diet with a different lipid level has not a significant role in the development of the scrapie disease. All infected mice fed with different diets died in the same time span. Histology, immunohistochemistry, and neuropathological analyses of the infected brains did not show significant differences between animals subjected to different diets.

SIGNIFICANCE

Independently of the diet, the infection induced a significant modification of the lipid composition in homogenates, and a less noticeable one in insoluble brain fraction.

Influence of a hyperlipidic diet on the composition of the non-membrane lipid pool of red blood cells of male and female rats

Background and objectives. Red blood cells (RBC) are continuously exposed to oxidative agents, affecting their membrane lipid function. However, the amount of lipid in RBCs is higher than the lipids of the cell membrane, and includes triacylglycerols, which are no membrane components. We assumed that the extra lipids originated from lipoproteins attached to the cell surface, and we intended to analyse whether the size and composition of this lipid pool were affected by sex or diet. Experimental design. Adult male and female Wistar rats were fed control or cafeteria diets. Packed blood cells and plasma lipids were extracted and analysed for fatty acids by methylation and GC-MS, taking care of not extracting membrane lipids. Results. The absence of ω3-PUFA in RBC extracts (but not in plasma) suggest that the lipids extracted were essentially those in the postulated lipid surface pool and not those in cell membrane. In cells' extracts, there was a marked depletion of PUFA (and, in general, of insaturation). Fatty acid patterns were similar for all groups studied, with limited effects of sex and no effects of diet in RBC (but not in plasma) fatty acids. Presence of trans fatty acids was small but higher in RBC lipids, and could not be justified by dietary sources. Conclusions. The presence of a small layer of lipid on the RBC surface may limit oxidative damage to the cell outer structures, and help explain its role in the transport of lipophilic compounds. However, there may be other, so far uncovered, additional functions for this lipid pool.

Analysis of electrocorticographic patterns in rats fed standard or hyperlipidic diets in a normal state or during status epilepticus

OBJECTIVE

The consumption of hyperlipidic diets has grown markedly in recent decades, and several studies have linked this consumption with the development of neurodegenerative diseases. Conversely, hyperlipidic diets have been used as an alternative therapy for refractory epilepsy. The purpose of this study was to evaluate the effects of a hyperlipidic diet on brain electrical activity before and during status epilepticus (SE) using computational and mathematical methods.

METHODS

Electrocorticogram (ECoG) was recorded in Wistar rats fed with standard and hyperlipidic diets. Each recording was obtained during 30-minute period (baseline), after this time, the SE was induced by pilocarpine, and recording was continued for another 30 minutes. The ECoG signals were analyzed by the following methods: power spectrum, Lempel-Ziv complexity (LZC), and fractal dimension of the phase space.

RESULTS

Hyperlipidic diet in normal animals caused a decrease in the theta, alpha, and beta rhythm, and reduced the LZC of the brain electrical activity. However, when the animals were induced to SE, these differences between nutritional groups were not observed. SE caused in both dietary groups increase in theta, alpha, and beta rhythm values, and increase in the complexity of brain electrical activity.

DISCUSSION

Hyperlipidic diet consumption attenuated the brain's electrical activity, suggesting that healthy individuals who habitually eat a hyperlipidic diet may develop dysfunctions such as cognitive decline and memory impairment. Furthermore, the antagonistic effect between hyperlipidic diet and SE suggests that this diet could protect against seizures.