Strawberry Intake Ameliorates Oxidative Stress and Decreases GABA Levels Induced by High-Fat Diet in Frontal Cortex of Rats

Greater resting state functional connectivity of the medial prefrontal cortex with the thalamus, caudate, and putamen in individuals who adhere to the Mediterranean style diets

PURPOSE

Healthy diets are believed to be associated with a reduced risk of experiencing common mental disorders (CMDs) and related symptomatology (such as ruminative thinking), and with healthier brain chemistry and structure, especially in the frontal regions implicated in CMDs, cognitive control, and food choice. Nevertheless, there is very limited research on the relationship between diet health/quality and brain function. In this study we assessed the associations between adherence to the Mediterranean diet and resting state functional connectivity (rs-FC) of the prefrontal cortex (PFC) with the whole brain and whether this connectivity would be associated with ruminative thinking as a transdiagnostic factor for CMDs.

METHODS

Thirty-seven adults (Mean Age = 25.57, SD = 7.18) completed the Mediterranean Diet Adherence Screener (MEDAS) and were classified into high- and low-quality diet groups and completed the Ruminative Response Scale. All participants underwent resting-state functional MRI (fMRI) to determine whole-brain rs-FC of the medial prefrontal cortex (mPFC).

RESULTS

Participants in the high MEDAS group (vs. low MEDAS group) exhibited significantly greater rs-FC of the mPFC seed with the thalamus, caudate and putamen. Additionally, the strength of rs-FC of the mPFC seed with these regions was positively associated with the MEDAS scores across groups in both crude and adjusted models. There were no significant associations between the strength of rs-FC of the mPFC seed with the cluster of voxels with the thalamus, caudate, and putamen and ruminative thinking.

DISCUSSION

This work shows that healthy dietary patterns are associated with rs-FC in the frontal-subcortical circuitry in healthy volunteers. Considering the implications of the dysregulation of this circuity, adhering to healthy dietary patterns may offer a promising alternative/complementary method to improve CMDs, cognitive control, and food choices.

The use of an in vitro fecal fermentation model to uncover the beneficial role of omega-3 and punicic acid in gut microbiota alterations induced by a Western diet

The influence of gut microbiota in the onset and development of several metabolic diseases has gained attention over the last few years. Diet plays an essential role in gut microbiota modulation. Western diet (WD), characterized by high-sugar and high-fat consumption, alters gut microbiome composition, diversity index, microbial relative levels, and functional pathways. Despite the promising health effects demonstrated by polyunsaturated fatty acids, their impact on gut microbiota is still overlooked. The effect of Fish oil (omega-3 source) and Pomegranate oil (punicic acid source), and a mixture of both oils in gut microbiota modulation were determined by subjecting the oil samples to in vitro fecal fermentations. Cecal samples from rats from two different dietary groups: a control diet (CD) and a high-fat high-sugar diet (WD), were used as fecal inoculum. 16S amplicon metagenomics sequencing showed that Fish oil + Pomegranate oil from the WD group increased α-diversity. This sample can also increase the relative abundance of the Firmicutes and Bacteroidetes phylum as well as Akkermansia and Blautia, which were affected by the WD consumption. All samples were able to increase butyrate and acetate concentration in the WD group. Moreover, tyrosine concentrations, a precursor for dopamine and norepinephrine, increase in the Fish oil + Pomegranate oil WD sample. GABA, an important neurotransmitter, was also increased in WD samples. These results suggest a potential positive impact of these oils' mixture on gut-brain axis modulation. It was demonstrated, for the first time, the great potential of using a mixture of both Fish and Pomegranate oil to restore the gut microbiota changes associated with WD consumption.

Adherence to unhealthy diets is associated with altered frontal gamma-aminobutyric acid and glutamate concentrations and grey matter volume: preliminary findings

OBJECTIVES

Common mental disorders (CMD) are associated with impaired frontal excitatory/inhibitory (E/I) balance and reduced grey matter volume (GMV). Larger GMV (in the areas that are implicated in CMD-pathology) and improved CMD-symptomatology have been observed in individuals who adhere to high quality diets. Moreover, preclinical studies have shown altered neurometabolites (primarily gamma-aminobutyric acid: GABA and glutamate: GLU) in relation to diet quality. However, neurochemical correlates of diet quality and how these neurobiological changes are associated with CMD and with its transdiagnostic factor, rumination, is unknown in humans. Therefore, in this study, we examined the associations between diet quality and frontal cortex neuro-chemistry and structure, as well as CMD and rumination in humans.

METHODS

Thirty adults were classified into high and low diet quality groups and underwent 1H-MRS to measure medial prefrontal cortex (mPFC) metabolite concentrations and volumetric imaging to measure GMV.

RESULTS

Low (vs High) diet quality group had reduced mPFC-GABA and elevated mPFC-GLU concentrations, as well as reduced right precentral gyrus (rPCG) GMV. However, CMD and rumination were not associated with diet quality. Notably, we observed a significant negative correlation between rumination and rPCG-GMV and a marginally significant association between rumination and mPFC-GLU concentrations. There was also a marginally significant association between mPFC-GLU concentrations and rPCG-GMV.

DISCUSSION

Adhering to unhealthy dietary patterns may be associated with compromised E/I balance, and this could affect GMV, and subsequently, rumination.

Immunostimulatory and anti-inflammatory impact of Fragaria ananassa methanol extract in a rat model of cadmium chloride-induced pulmonary toxicity

Cadmium is an extremely dangerous heavy metal that can lead to disastrous consequences in all organisms. Several natural remedies reduce the toxicities of experimentally generated metals in animals. Strawberry Fragaria ananassa contains several bioactive compounds that may mitigate heavy-metal toxicity. The study aim was to evaluate the ability of a strawberry fruit methanol extract (SE) to reduce Cd toxicity and to identify and quantify the active constituents of SE. Forty Wistar rats were classified into four groups: the control group- 1 ml saline IP; SE group- 100 mg of SE/kg rats orally; cadmium (Cd) group-2 mg CdCl2/kg body weight/IP daily; and treated group- SE given 1 hour before Cd administration. Administration of Cd induced several histopathological and immunohistochemical alterations in lung sections. Biochemical analysis of lung homogenates and mRNA levels of antioxidants and inflammatory cytokines indicated significant changes to the risk profile. SE administration significantly decreased the oxidative stress, inflammation, tissue damage, the mean area percentage of collagen fibers, and positive immuno-expressions of TNF-α and NF-κB induced by CdCl2. Moreover, the MDA, TNF-α, GM-CSF, and IL-1β levels in Cd-exposed rat lung tissue were significantly lower in the SE-treated group than in the Cd-group. SE significantly augmented lung GSH, SOD, HO-1, GPx-2, and Nrf2 levels in Cd-exposed rats. SE mitigated Cd-caused oxidative stress and lung inflammation. Therefore, regularly consuming a strawberry-rich diet could benefit general health and help prevent and treat diseases.

Effect of berrycactus fruit (Myrtillocactus geometrizans) on glutamate, glutamine, and GABA levels in the frontal cortex of rats fed with a high-fat diet

In addition to the known metabolic alterations, obesity has consequences at the brain level, driving imbalance in neurotransmitters such as glutamate (Glu), glutamine (Gln), and gamma-aminobutyric acid (GABA). The consumption of fruits with antioxidant properties, such as the berrycactus Myrtillocactus geometrizans, could have beneficial effects in such an imbalance. The study objective was to evaluate frontal cortex neurotransmitter levels and weight changes in rats fed with a high-fat diet (HFD) and MG. To achieve that, five groups of Wistar rats received different diets for 24 weeks: standard diet (SDt), HFD, HFD + MG extract 150 mg (HMg150), HFD + MG extract 300 mg (HMg300), and HFD + MG extract 450 mg (HMg450); rats received MG extract for the last 4 weeks. Weight and food intake were recorded every week, and also neurotransmitter levels were quantified using high-performance liquid chromatography. Groups fed with HFDs had increased Glu and Gln levels, decreased GABA, and also gained more weight compared to the SDt group; MG extract of 450 mg decreased Glu levels. Concentrations of 300 and 450 mg of MG extract decreased weight compared to the HFD and HMg150 groups. This study reports that HFDs have an impact on neurotransmitter levels and weight, MG extract showed a reduction in Glu concentration and weight.

Neuroinflammation: The Role of Anthocyanins as Neuroprotectants

Neuroinflammation is a trigger for several neurodegenerative and neuropsychiatric disorders. Exposure to noxious external stimuli induces homeostatic disturbances resulting in morphological changes in microglia, their activation, and elaboration of pro-inflammatory mediators. This leads to neuroinflammation with the progressive loss of neurons. Nutraceuticals such as anthocyanins are a class of brightly colored bioactive compounds present in fruits and vegetables with purported health benefits. They interfere with the activation of several signaling cascades that have a prominent role in preventing neuroinflammation. More importantly, anthocyanins can cross the blood-brain barrier and are safe. Hence, the current review focuses on the bioavailability of anthocyanins, clinical and in vitro evidence on their role in impeding the activation of transcription factors, modulating the immune milieu within the central nervous system, preventing the activation of microglia, and averting neuroinflammation.

Agomelatine effects on fat-enriched diet induced neuroinflammation and depression-like behavior in rats

Growing evidence suggests that a high fat diet (HFD) induces oxidative stress on the central nervous system (CNS), which predisposes to mood disorders and neuroinflammation. In this study we postulated that in addition to improving mood, antidepressant therapy would reverse inflammatory changes in the brain of rats exposed to a HFD. To test our hypothesis, we measured the effect of the antidepressant agomelatine (AGO) on anxiety- and depressive-like behaviors, as well as on CNS markers of inflammation in rats rendered obese. Agomelatine is an agonist of the melatonin receptors MT1 and MT2 and an antagonist of the serotonin receptors 5HT2B and 5HT2C. A subset of rats was also treated with lipopolysaccharides (LPS) to determine how additional neuroinflammation alters behavior and affects the response to the antidepressant. Specifically, rats were subjected to a 14-week HFD, during which time behavior was evaluated twice, first at the 10th week prior to LPS and/or agomelatine, and then at the 14th week after a bi-weekly exposure to LPS (250 μg/kg) and daily treatment with agomelatine (40 mg/kg). Immediately after the second behavioral testing we measured the proinflammatory cytokines tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6) and interleukin 1 beta (IL-1β), markers of oxidative stress thiobarbituric acid reactive substances (TABRS), catalase (CAT) and glutathione peroxidase (GPx), the growth factor BDNF, as well as the apoptosis marker caspase-3. Our results show that a HFD induced an anxiety-like behavior in the open field test (OFT) at the 10th week, followed by a depressive-like behavior in the forced swim test (FST) at the 14th week. In the prefrontal and hippocampal cortices of rats exposed to a HFD we noted an overproduction of TNF-α, IL-6, IL-1β, and TABRS, together with an increase in caspase-3 activity. We also observed a decrease in BDNF, as well as reduced CAT and GPx activity in the same brain areas. Treatment with agomelatine reversed the signs of anxiety and depression, and decreased the cytokines (TNF-α, IL-6 and IL-1β), TABRS, as well as caspase-3 activity. Agomelatine also restored BDNF levels and the activity of antioxidant enzymes CAT and GPx. Our findings suggest that the anxiolytic/antidepressant effect of agomelatine in obese rats could result from a reversal of the inflammatory and oxidative stress brought about by their diet.

Phytosterol Extract Decreases the Oxidative Damage in the Brains of Diabetic db/db Mice

Introduction: Hypercaloric diets induce oxidative stress, and consequently induce hyperglycemia and type 2 diabetes mellitus (T2DM). Thus, oxidative stress is significantly increased in T2DM, leading to oxidative damage to brain, which might contribute to cognitive deficits and neurodegenerative diseases. Therefore, reducing the oxidative stress is important to preserving cognitive functions, and it has been suggested that phytosterols may reduce the oxidative stress. Objective: The objective of the present study was to determine the effects of phytosterols derived from corn on oxidative damage in the cerebellum, frontal cortex, and hippocampus of diabetic db/db mice. Materials and Methods: A phytosterol extract was isolated from yellow corn (Zea mays L.) and 100 mg/kg of the extract was administrated daily to diabetic mice for 8 weeks. At the end of the treatment period, tissues were isolated to determine the levels of oxidized lipid and protein. Results: The phytosterol treatment increased body weight in diabetic db/db mice, but this treatment did not have any effects on body weight in wild-type mice. Moreover, the phytosterol treatment decreased levels of oxidized lipids in the cerebellum, frontal cortex, and hippocampus, and also decreased the levels of oxidized proteins in the cerebellum and frontal cortex in diabetic db/db mice. Conclusion: These important results show that phytosterol treatment can reduce oxidative damage in the brains of diabetic mice.

Select Polyphenol-Rich Berry Consumption to Defer or Deter Diabetes and Diabetes-Related Complications

Berries are considered "promising functional fruits" due to their distinct and ubiquitous therapeutic contents of anthocyanins, proanthocyanidins, phenolic acids, flavonoids, flavanols, alkaloids, polysaccharides, hydroxycinnamic, ellagic acid derivatives, and organic acids. These polyphenols are part of berries and the human diet, and evidence suggests that their intake is associated with a reduced risk or the reversal of metabolic pathophysiologies related to diabetes, obesity, oxidative stress, inflammation, and hypertension. This work reviewed and summarized both clinical and non-clinical findings that the consumption of berries, berry extracts, purified compounds, juices, jams, jellies, and other berry byproducts aided in the prevention and or otherwise management of type 2 diabetes mellitus (T2DM) and related complications. The integration of berries and berries-derived byproducts into high-carbohydrate (HCD) and high-fat (HFD) diets, also reversed/reduced the HCD/HFD-induced alterations in glucose metabolism-related pathways, and markers of oxidative stress, inflammation, and lipid oxidation in healthy/obese/diabetic subjects. The berry polyphenols also modulate the intestinal microflora ecology by opposing the diabetic and obesity rendered symbolic reduction of Bacteroidetes/Firmicutes ratio, intestinal mucosal barrier dysfunction-restoring bacteria, short-chain fatty acids, and organic acid producing microflora. All studies proposed a number of potential mechanisms of action of respective berry bioactive compounds, although further mechanistic and molecular studies are warranted. The metabolic profiling of each berry is also included to provide up-to-date information regarding the potential anti-oxidative/antidiabetic constituents of each berry.