Fructose Intake Impairs Cortical Antioxidant Defenses Allied to Hyperlocomotion in Middle-Aged C57BL/6 Female Mice

Mechanisms Underlying Memory Impairment Induced by Fructose

Fructose consumption has increased over the years, especially in adolescents living in urban areas. Growing evidence indicates that daily fructose consumption leads to some pathological conditions, including memory impairment. This review summarizes relevant data describing cognitive deficits after fructose intake and analyzes the underlying neurobiological mechanisms. Preclinical experiments show sex-related deficits in spatial memory; that is, while males exhibit significant imbalances in spatial processing, females seem unaffected by dietary supplementation with fructose. Recognition memory has also been evaluated; however, only female rodents show a significant decline in the novel object recognition test performance. According to mechanistic evidence, fructose intake induces neuroinflammation, mitochondrial dysfunction, and oxidative stress in the short term. Subsequently, these mechanisms can trigger other long-term effects, such as inhibition of neurogenesis, downregulation of trophic factors and receptors, weakening of synaptic plasticity, and long-term potentiation decay. Integrating all these neurobiological mechanisms will help us understand the cellular and molecular processes that trigger the memory impairment induced by fructose.

Feeding the Brain: Effect of Nutrients on Cognition, Synaptic Function, and AMPA Receptors

In recent decades, traditional eating habits have been replaced by a more globalized diet, rich in saturated fatty acids and simple sugars. Extensive evidence shows that these dietary factors contribute to cognitive health impairment as well as increase the incidence of metabolic diseases such as obesity and diabetes. However, how these nutrients modulate synaptic function and neuroplasticity is poorly understood. We review the Western, ketogenic, and paleolithic diets for their effects on cognition and correlations with synaptic changes, focusing mainly (but not exclusively) on animal model studies aimed at tracing molecular alterations that may contribute to impaired human cognition. We observe that memory and learning deficits mediated by high-fat/high-sugar diets, even over short exposure times, are associated with reduced arborization, widened synaptic cleft, narrowed post-synaptic zone, and decreased activity-dependent synaptic plasticity in the hippocampus, and also observe that these alterations correlate with deregulation of the AMPA-type glutamate ionotropic receptors (AMPARs) that are crucial to neuroplasticity. Furthermore, we explored which diet-mediated mechanisms modulate synaptic AMPARs and whether certain supplements or nutritional interventions could reverse deleterious effects, contributing to improved learning and memory in older people and patients with Alzheimer’s disease.

A high-fat, high-fructose diet induced hepatic steatosis, renal lesions, dyslipidemia, and hyperuricemia in non-obese rats

Excessive consumption of fat and sugar is associated with various chronic diseases. However, the variation of fat and sugar content in the diet greatly affected the outcome. In this study, a high-fat, high-fructose diet (HFHFD) formula was made with a composition of 31.99% carbohydrate, 40.7% fat, 11.8% protein, and an additional 30% fructose drink to confirm the effects of HFHFD on metabolic health and pathological changes in organs, especially the liver, kidneys, pancreas, muscles, and spleen. A total of 24 male Wistar rats aged 8–12 weeks were divided into four groups: standard chow (SC), HFHFD, SC + carbon tetrachloride (CCl4), and HFHFD + CCl4. After eight weeks of dietary intervention, body mass index, obesity index, lipid profiles, liver function tests, fasting blood glucose, serum uric acid and urea levels, and tissue histopathology were examined. HFHFD with the main unsaturated fatty acids of linoleic acid (14.57%) and palmitoleic acid (8.28%), the main saturated fatty acids of stearic acid (13.62%) and myristic acid (10.09%), and a low trans-fatty acids content, did not promote the rats to become obese. However, liver histology examination showed severe hepatic steatosis (78.33%), leading to steatohepatitis accompanied by an increase in serum ALP (p < 0.01), triglyceride (p < 0.001), total cholesterol (p < 0.05), and uric acid (p < 0.001) levels. Other histological features showed moderate lesions (45%) of the kidney, slight vacuolization of the pancreas, and a mild increase of inflammatory cells in the spleen and muscle. So, this study found that although HFHFD did not promote obesity within 8 weeks of administration, it induced hepatic and renal lesions, dyslipidemia, and hyperuricemia as a metabolic consequence of excessive fatty acids and fructose.

Are fat and sugar just as detrimental in old age?

Aging and poor nutrition are independent risk factors for the development of chronic disease. When young animals are given diets high in fat or sugar, they exhibit hallmarks of aging like mitochondrial dysfunction and inflammation, and also develop a greater risk for age-related disease. The same mitochondrial dysfunction and inflammation that progress with aging may also further predispose older individuals to dietary insults by fat and sugar. The purpose of this work is to review the most recent studies that address the impact of fat and sugar consumption on hallmarks of aging (mitochondrial dysfunction and inflammation). Findings from these studies show that obesogenic, high-fat diets can exacerbate age-related disease and hallmarks of aging in young animals, but high-fat diets that are non-obesogenic may play a beneficial role in old age. In contrast, high-sugar diets do not require an obesogenic effect to induce mitochondrial dysfunction or inflammation in young rodents. Currently, there is a lack of experimental studies addressing the impact of sugar in the context of aging, even though empirical evidence points to the detrimental effect of sugar in aging by contributing to a variety of age-related diseases. Fig. 1 Mitochondrial dysfunction and altered cellular communication (e.g. inflammation) progress with advancing age and increase the risk for age-related disease (ARD). Given the physiological changes that occur with age, the impact of high-fat (HFD) and high-sugar diets (HSD) may differ in later and earlier stages of life. HFD can promote the development of hallmarks of aging in young animals and can also exacerbate the risk for ARD when consumed at an old age. However, non-obesogenic high-fat diets may also reduce the risk for ARD in old age by acting on these hallmarks of aging. On the other hand, HSD promotes mitochondrial dysfunction and inflammation without necessarily inducing weight gain in young animals. Empirical evidence points to sugar as a major contributor to age-related disease and more experimental studies are needed to clarify whether aged individuals are more susceptible to its effects.

Design, synthesis, and biological studies of novel 3-benzamidobenzoic acid derivatives as farnesoid X receptor partial agonist

Farnesoid X receptor (FXR), a bile acid-activated nuclear receptor, regulates the metabolism of bile acid and lipids as well as maintains the stability of internal environment. FXR was considered as a therapeutic target of liver disorders, such as drug-induced liver injury, fatty liver and cholestasis. The previous reported FXR partial agonist 6 was a suitable lead compound in terms of its high potent and low molecular size, while the docking study of compound 6 suggested a large unoccupied hydrophobic pocket, which might be provided more possibility of structure-activity relationship (SAR) study. In this study, we have performed comprehensive SAR and molecular modeling studies based on lead compound 6. All of these efforts resulted in the identification of a novel series of FXR partial agonists. In this series, compound 41 revealed the best activity and strong interaction with binding pocket of FXR. Moreover, compound 41 protected mice against acetaminophen-induced hepatotoxicity by the regulation of FXR-related gene expression and improving antioxidant capacity. In summary, these results suggest that compound 41 is a promising FXR partial agonist suitable for further investigation.