Fructose: Toxic effect on cardiorenal risk factors and redox state

New insights toward molecular and nanotechnological approaches to antidiabetic agents for Alzheimer's disease

Alzheimer's disease (AD) is a chronic neurodegenerative disorder affecting a major class of silver citizens. The disorder shares a mutual relationship on account of its cellular and molecular pathophysiology with type-II diabetes mellitus (DM). Chronic DM increases the risk for AD. Emerging evidence recommended that resistance in insulin production develops cognitive dysfunction, which generally leads to AD. Repurposing of antidiabetic drugs can be effective in preventing and treatment of the neurodegenerative disorder. Limitations of antidiabetic drugs restrict the repurposing of the drugs for other disorders. Therefore, nanotechnological intervention plays a significant role in the treatment of neurological disorders. In this review, we discuss the common cellular and molecular pathophysiologies between AD and type-II DM, the relevance of in vivo models of type II DM in the study of AD, and the repurposing of antidiabetic drugs and the nanodelivery systems of antidiabetic drugs against AD.

Fructose Consumption Alters Biogenic Amines Associated with Cardiovascular Disease Risk Factors

BACKGROUND

Cardiovascular diseases (CVD) are the major cause of mortality worldwide, whose most prominent risk factor is unhealthy eating habits, such as high fructose intake. Biogenic amines (BAs) perform important functions in the human body. However, the effect of fructose consumption on BA levels is still unclear, as is the association between these and CVD risk factors.

OBJECTIVE

This study aimed to establish the association between BA levels and CVD risk factors in animals that consumed fructose.

METHODS

Male Wistar rats received standard chow (n=8) or standard chow + fructose in drinking water (30%) (n=8) over a 24-week period. At the end of this period, the nutritional and metabolic syndrome (MS) parameters and plasmatic BA levels were analyzed. A 5% level of significance was adopted.

RESULTS

Fructose consumption led to MS, reduced the levels of tryptophan and 5-hydroxitryptophan, and increased histamine. Tryptophan, histamine, and dopamine showed a correlation with metabolic syndrome parameters.

CONCLUSION

Fructose consumption alters BAs associated with CVD risk factors.

Effect of Curcumin Nanoemulsions Stabilized with MAG and DAG-MCFAs in a Fructose-Induced Hepatic Steatosis Rat Model

Current changes in diet, characterized by an increase in the intake of sweetened beverages, are heavily related to metabolic disorders such as non-alcoholic fatty liver. This condition can produce simple steatosis and, in worse cases, potentially result in steatohepatitis, fibrosis, and cirrhosis, comparable to the damage caused by the consumption of more or less 20–30 g of alcohol per day. The main objective of this research was to evaluate the effect of curcumin (Curcuma longa) nanoemulsions, using mono- and diacylglycerides medium chain fatty acids as stabilizers in an in vivo hepatic steatosis rat model. Pathology was induced by providing 30% fructose intake in the drinking water. Globule sizes under 200 nm that were stable for 4 weeks were obtained; curcumin encapsulated in the nanoemulsion was >70%. The results revealed an improvement regarding body and liver weight in the animals treated with curcumin nanoemulsions. A decrease in total cholesterol, LDL, AST/ALT, and HDL in serum was observed; however, no apparent improvement regarding serum glucose or triacylglycerides values was noted. Histological analysis showed a significant decrease in the extent of steatosis, inflammation, and brown adipose tissue in the treated animals.

Low-intensity exercise diverts cardiac fatty acid metabolism from triacylglycerol synthesis to beta oxidation in fructose-fed rats

CONTEXT

Excessive fructose consumption causes ectopic lipid storage leading to metabolic disorders and cardiovascular diseases associated with defective substrate utilisation in the heart.

OBJECTIVE

Examining the preventive impact of low-intensity exercise on alterations related to fructose-rich diet (FRD) on cardiac fatty acid (FA) transport and metabolism.

MATERIALS AND METHODS

Male Wistar rats were divided into control and two groups that received 10% fructose for 9 weeks, one of which was additionally exposed to exercise.

RESULTS

FRD elevated plasma and cardiac TAG, FATP1 in plasma membrane, Lipin 1 in microsomes and HSL mRNA, while mitochondrial CPT1 was decreased. Exercise decreased plasma free FA level, raised CD36 in plasma membrane and FATP1 in lysate, mitochondrial CPT1 and decreased microsomal Lipin 1 in fructose-fed rats.

CONCLUSIONS

FRD changed plasma lipids and augmented partitioning of FA to TAG storage in the heart, whereas exercise in FRD rats switched metabolism of FA towards β-oxidation.

Effects of TNF-α antagonist infliximab on fructose-induced metabolic syndrome in rats

Public health issues have been raised regarding fructose toxicity and its serious metabolic disorders. Deleterious effects of high fructose intake on insulin sensitivity, body weight, lipid homeostasis have been identified. The new millennium has witnessed the emergence of a modern epidemic, the metabolic syndrome (MS), in approximately 25% of the world's adult population. The current study aimed to investigate the effect of the TNF-α antagonist infliximab on fructose-induced MS in rats. Rats were administered fructose (10%) in drinking water for 12 weeks to induce the experimental MS model. infliximab (5 mg/kg) was injected once weekly intraperitoneally starting on the 13th week for 4 weeks. Increase in body weight, blood glucose level, serum triglycerides (TGs), adiponectin level and blood pressure were present in MS rats. They also prompted increases in serum of leptin, TNF-α, and malondialdehyde (MDA) levels. Treatment with infliximab did not affect body weight, hyperglycemia or hypertension, but decreased serum TGs and increased serum HDL-c levels. Infliximab also decreased adiponectin levels. Surprisingly, infliximab increased MDA above its value in the MS group. These results reflect the fact that infliximab affects the manifestations of MS in rats. Though infliximab reduced TGs, increased HDL-c levels, reversed adiponectin resistance occurred by fructose, the drug failed to combat MS-mediated hyperglycemia, hypertension, and elevated MDA above the insult.

Impact of combined exercise training on the development of cardiometabolic and neuroimmune complications induced by fructose consumption in hypertensive rats

This study evaluated the impact of combined exercise training on the development of cardiovascular and neuroimmune complications induced by fructose consumption (10% in the drinking water) in hypertensive rats (SHR). After weaning, SHR were divided into 3 groups: SHR (H), SHR+fructose (HF) and SHR+fructose+combined exercise training (treadmill+ladder, 40-60% of maximum capacity) (HFTC). Metabolic, hemodynamic, autonomic, inflammatory and oxidative stress parameters were evaluated in the subgroups (n = 6 group/time) at 7, 15, 30 and 60 days of protocol. Fructose consumption (H vs. HF groups) decreased spontaneous baroreflex sensitivity and total variance of pulse interval at day 7 (7 to 60); increased IL-6 and TNFα in the heart (at day 15, 30 and 60) and NADPH oxidase activity and cardiac lipoperoxidation (LPO) (day 60); increased white adipose tissue weight, reduced insulin sensitivity and increased triglycerides (day 60); induced an additional increase in mean arterial pressure (MAP) (days 30 and 60). Combined exercise training prevented such dysfunctions and sustained increased cardiac IL-10 (day 7) and glutathione redox balance (GSH/GSSG) for the entire protocol. In conclusion, combined exercise training performed simultaneously with exacerbated fructose consumption prevented early cardiovascular autonomic dysfunction, probably trigging positive changes in inflammation and oxidative stress, resulting in a better cardiometabolic profile in rats genetically predisposed to hypertension.

Astaxanthin alleviates renal damage of rats on high fructose diet through modulating NFκB/SIRT1 pathway and mitigating oxidative stress

This study was conducted to determine the effect of astaxanthin (ASX) treatment on alleviation of renal damage in high fructose induced nephrotoxicity in rats. Treatments were arranged in a 2 × 2 factorial fashion: administrations of fructose (30%, via drinking water) and ASX (1 mg/kg/day, within 0.2 ml olive oil) for 8 weeks. Data were analyzed by two-way ANOVA. The ASX treatment decreased serum urea (p < .01) and blood urea-N concentrations (p < .02) at a lower extent in rats receiving fructose than those not receiving fructose. Moreover, the ASX treatment reversed the increases in malondialdehyde (MDA) (p < .0001) and nuclear factor kappa B (NF-κB) (p < .0003) levels and the decreases in superoxide dismutase (SOD) activity (p < .0001) and sirtuin-1 (SIRT1) level (p < .0004), in the kidney upon high fructose consumption. The data suggest that ASX supplementation alleviates renal damage induced by high fructose consumption through modulating NF-κB/SIRT1 pathway and mitigating oxidative stress.

The Effect of High Fat High Fructose Diet (Modification of AIN-93M) on Nuclear Factor Kappa Beta Expression in the Liver Tissue of Male Sprague Dawley Rats

Metabolic inflammation (low-grade inflammation) remains an etiopathogenic key factor in the development of metabolic syndrome. Nuclear Factor Kappa Beta (NF-κβ) is a transcription regulator of genes having a role in immunity, the inflammatory response which can be associated with obesity-related pathological conditions like nonalcoholic fatty liver (NAFLD). Various stimuli, such as metabolic stress (hyperglycemia, ROS, fat metabolism) and proinflammatory cytokines (TNF-α, IL-6, IL-1β) could activate NF-κβ. This study was aimed to investigate the underlying molecular mechanisms of NAFLD in rats fed a modified AIN-93M HFHF (High Fat High Fructose) diet. The design of this study was experimental post-test only controlled group design. Thirty male Sprague Dawley rats were distributed into 2 treatment groups by a completely randomized design (CRD) technique. The sacrifice was performed after 17 weeks of treatment. NF-κβ expression was assessed by an immunohistochemical method (IRS score). The results showed there were significant differences in feed intake and energy intake between groups P1 and P2 (p = 0,000, p = 0,000). The average NF-κβ expression in the P2 group was significantly higher (p = 0.000) compared to the control group (P1). The correlation test between dietary intake and NF-κβ expression proved that there was a positive correlation between energy, carbohydrate and fat intake on NF-κβ expression (p = 0.001, 0.000, 0.046). However, there was a negative relationship between protein intake and NF-κβ expression (p = 0.000). This study concluded the modified AIN-93M HFHF diet increased NF-κβ expression in the liver tissue of male Sprague Dawley rats.

Amelioration of Abnormalities Associated with the Metabolic Syndrome by Spinacia oleracea (Spinach) Consumption and Aerobic Exercise in Rats

The present study evaluates the protective effects of an antioxidant-rich extract of Spinacea oleracea (NAOE) in abnormalities associated with the metabolic syndrome (MetS) in rats. HPTLC of NAOE revealed the presence of 13 total antioxidants, 14 flavonoids, and 10 phenolic acids. Rats administered with fructose (20% w/v) in drinking water for 45 days to induce abnormalities of MetS received NAOE (200 and 400 mg/kg, po), the standard drug gemfibrozil (60 mg/kg, po), aerobic exercise (AE), and a combination of NAOE 400 mg/kg and AE (NAOEAE) daily for 45 days. All treatments significantly altered the lipid profile and attenuated the fructose-elevated levels of uric acid, C-reactive protein, homocysteine, and marker enzymes (AST, LDH, and CK-MB) in serum and malondialdehyde in the heart and restored the fructose-depleted levels of glutathione and antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase). A significant decrease in blood glucose and insulin levels decreased insulin resistance, and improved glucose tolerance was observed in the treatment animals when compared with the fructose-fed animals. The best mitigation of MetS was shown by the NAOEAE treatment indicating that regular exercise along with adequate consumption of antioxidant-rich foods such as spinach in diet can help control MetS.