The influence of the polyunsaturated fatty acids on body weight and anxiolytic-like behavior in female rats

DHA/EPA supplementation decreases anxiety-like behaviour, but it does not ameliorate metabolic profile in obese male rats

Obesity is a major public health problem that predisposes to several diseases and higher mortality in patients with COVID-19. Obesity also generates neuroinflammation, which predisposes to the development of neuropsychiatric diseases. Since there is a lack of effective treatments for obesity, the search for new strategies to reverse its consequences is urgent. In this perspective, the anti-inflammatory properties of omega-3 polyunsaturated fatty acids such as DHA/EPA might reduce the harmful effects of obesity. Here, we used the cafeteria diet (CAF) model to induce obesity in Wistar rats. Animals received ultra-processed food for 20 weeks, and DHA/EPA supplementation (500 mg/kg per d) was performed between the 16th and the 20th week. At the end of the experiment, it was evaluated: body weight, visceral fat deposition, plasma glucose, insulin and triglycerides, and it was also measured the levels of inflammatory cytokines TNF-α and IL-6 in plasma and liver, and TNF-α in the prefrontal cortex. The elevated plus maze test was performed to analyse anxiety-like behaviour. Our results demonstrated that DHA/EPA could not reverse weight and fat gain and did not modify plasma dosages. However, there was a decrease in IL-6 in the liver (DHA/EPA effect: P = 0.023) and TNF-α in the brain (CAF compared with CAF + DHA/EPA, P < 0.05). Also, there was a decrease in the anxiety index in CAF + DHA/EPA compared with the CAF group (P < 0.01). Thus, DHA/EPA supplementation is helpful to reverse the consequences of obesity in the brain.

Sex-Dependent Effects of Eicosapentaenoic Acid on Hepatic Steatosis in UCP1 Knockout Mice

Visceral obesity may be a driving factor in nonalcoholic fatty liver disease (NAFLD) development. Previous studies have shown that the omega-3 polyunsaturated fatty acid, eicosapentaenoic acid (EPA), ameliorates obesity in high-fat (HF) fed male, C57Bl/6 mice at thermoneutral conditions, independent of uncoupling protein 1 (UCP1). Our goals herein were to investigate sex-dependent mechanisms of EPA in the livers of wild type (WT) and UCP1 knockout (KO) male and female mice fed a HF diet (45% kcal fat; WT-HF, KO-HF) with or without supplementation of 36 g/kg EPA (WT-EPA, KO-EPA). KO significantly increased body weight in males, with no significant reductions with EPA in the WT or KO groups. In females, there were no significant differences in body weight among KO groups and no effects of EPA. In males, liver TGs were significantly higher in the KO-HF group and reduced with EPA, which was not observed in females. Accordingly, gene and protein markers of mitochondrial oxidation, peroxisomal biogenesis and oxidation, as well as metabolic futile cycles were sex-dependently impacted by KO and EPA supplementation. These findings suggest a genotypic difference in response to dietary EPA supplementation on the livers of male and female mice with diet-induced obesity and housed at thermoneutrality.

Comparison of the effect of rapeseed oil or amaranth seed oil supplementation on weight loss, body composition, and changes in the metabolic profile of obese patients following 3-week body mass reduction program: a randomized clinical trial

BACKGROUND

Amaranth seed oil (ASO) and rapeseed oil (RSO) are functional foods that display antioxidant and hepatoprotective properties. These oils are also known to lower glucose and cholesterol levels. The current study compared the effects exerted by RSO and ASO on weight loss and metabolic parameters during a 3-week body mass reduction program.

METHODS

Eighty-one obese subjects (BMI > 30 kg/m2), aged 25-70 years, were enrolled in a 3-week body mass reduction program based on a calorie-restricted diet and physical activity. Participants were randomly categorized into an AO group (administered 20 mL/d of ASO), a RO group (administered 20 mL/d of RSO), and a C group (control; untreated). Anthropometric and metabolic parameters were measured at baseline and endpoint.

RESULTS

Significant decreases in weight, body mass index (BMI), waist circumference (WC), hip circumference (HC), fat mass (FM), lean body mass (LBM), visceral fat mass (VFM), and total body water (TBW%) were observed in all groups (P <  0.05). No significant improvements were observed in the clinical parameters of group C. Fasting insulin (Δ - 5.9, and Δ - 5.7) and homeostatic model assessment of insulin resistance (HOMA-IR) (Δ - 1.1 and Δ - 0.5) were decreased in both RO and AO groups, respectively. Fasting glucose (Δ -8.5; P = 0.034), total cholesterol (Δ -14.6; P = 0.032), non-HDL cholesterol (Δ 15.9; P = 0.010), TG/HDL ratio (Δ -0.6; P = 0.032), LDL cholesterol (Δ -12.3; P = 0.042), and triglycerides (Δ -6.5; P = 0.000) were significantly improved in the AO group, compared to the RO group.

CONCLUSIONS

The 3-week body mass reduction intervention caused a significant reduction in the weight, BMI, WC, HC, FM, and VFM of all groups. Except for HOMA-IR, there were no statistical differences between the clinical parameters of all groups. However, a trend toward improved insulin levels and HDL% was noticeable in AO and RO. Therapies involving edible oils with high nutritional value, such as RSO and ASO, show potential for improving metabolic measurements during body mass reduction programs. Thus, obese patients undertaking weight reduction programs may benefit from RSO and ASO supplementation.

TRIAL REGISTRATION

retrospectively registered, DRKS00017708.

Omega-3 fatty acids in obesity and metabolic syndrome: a mechanistic update

Strategies to reduce obesity have become public health priorities as the prevalence of obesity has risen in the United States and around the world. While the anti-inflammatory and hypotriglyceridemic properties of long-chain omega-3 polyunsaturated fatty acids (n-3 PUFAs) are well known, their antiobesity effects and efficacy against metabolic syndrome, especially in humans, are still under debate. In animal models, evidence consistently suggests a role for n-3 PUFAs in reducing fat mass, particularly in the retroperitoneal and epididymal regions. In humans, however, published research suggests that though n-3 PUFAs may not aid weight loss, they may attenuate further weight gain and could be useful in the diet or as a supplement to help maintain weight loss. Proposed mechanisms by which n-3 PUFAs may work to improve body composition and counteract obesity-related metabolic changes include modulating lipid metabolism; regulating adipokines, such as adiponectin and leptin; alleviating adipose tissue inflammation; promoting adipogenesis and altering epigenetic mechanisms.

Oral 2-hydroxyoleic acid inhibits reflex hypersensitivity and open-field-induced anxiety after spared nerve injury

BACKGROUND

Recently, fatty acids have been shown to modulate sensory function in animal models of neuropathic pain. In this study, the antinociceptive effect of 2-hydroxyoleic acid (2-OHOA) was assessed following spared nerve injury (SNI) with reflex and cerebrally mediated behavioural responses.

METHODS

Initial antinociceptive behavioural screening of daily administration of 2-OHOA (400 mg/kg, p.o.) was assessed in Wistar rats by measuring hindlimb reflex hypersensitivity to von Frey and thermal plate stimulation up to 7 days after SNI, while its modulatory effect on lumbar spinal dorsal horn microglia reactivity was assessed with OX-42 immunohistochemistry. In vitro the effect of 2-OHOA (120 μM) on cyclooxygenase protein expression (COX-2/COX-1 ratio) in lipopolysaccharide-activated macrophage cells was tested with Western blot analysis. Finally, the effects of 2-OHOA treatment on the place escape aversion paradigm (PEAP) and the open-field-induced anxiety test were tested at 21 days following nerve injury compared with vehicle-treated sham and pregabalin-SNI (30 mg/kg, p.o.) control groups.

RESULTS

Oral 2-OHOA significantly reduced ipsilateral mechanical and thermal hypersensitivity up to 7 days after SNI. Additionally 2-OHOA decreased the COX-2/COX-1 ratio in lipopolysaccharide-activated macrophage cells and OX-42 expression within the ipsilateral lumbar spinal dorsal horn 7 days after SNI. 2-OHOA significantly restored inner-zone exploration in the open-field test compared with the vehicle-treated sham group at 21 days after SNI.

CONCLUSIONS

Oral administration of the modified omega 9 fatty acid, 2-OHOA, mediates antinociception and prevents open-field-induced anxiety in the SNI model in Wistar rats, which is mediated by an inhibition of spinal dorsal horn microglia activation.