Effect of flaxseed on systemic inflammation and oxidative stress in diabetic rats with or without chronic kidney disease

Beneficial Effects of Dietary Flaxseed Oil through Inflammation Pathways and Gut Microbiota in Streptozotocin-Induced Diabetic Mice

Flaxseed oil (FO) has displayed potential anti-diabetes properties by providing a high content of α-linolenic acid. However, the effects and mechanisms of FO on type 1 diabetes are still unclear. The present study aims to explore the effects of different doses of FO feeding on hepatic inflammation and gut microbiota in streptozotocin-induced diabetic mice. Forty-eight six-week-old C57BL/6J male mice were divided into a control group (CON), a diabetic group (MOD), a diabetes with 7.0% w/w FO feeding group (FO-L), and a diabetes with 10.5% w/w FO feeding group (FO-H) for six weeks. The 7.0% w/w and 10.5% w/w FO feeding groups exhibited potential recovery of the number and size of pancreas tissues. The fasting blood glucose level was significantly decreased only after 4 weeks of feeding with 10.5% w/w FO in diabetic mice. The 10.5% w/w FO feeding group significantly decreased the postprandial blood glucose level of mice in the OGTT test. Hepatic glycogen levels were dramatically upregulated in the mice fed with both 7.0% w/w and 10.5% w/w FO. FO feeding significantly attenuated hepatic LPS, TNF-α, and IL-1β levels. In addition, we observed that 7.0% w/w and 10.5% w/w FO feedings notably downregulated hepatic gene and protein expressions of TLR4, MyD88, and P65. Furthermore, only 10.5% FO regulated fecal microbiota by increasing the relative abundance of the Bacteroidetes phylum, Lactococcus family, and Muribaculaceae and Streptococcaceae family and genus in streptozotocin-induced diabetic mice. Therefore, we conclude that FO feeding plays a role in anti-inflammation via the regulation of hepatic LPS/TLR4/MyD88 pathways and gut microbiota. In addition, different doses of FO supplementation may exhibit varying mechanisms in streptozotocin-induced mice.

Animal Models for Studying Protein-Bound Uremic Toxin Removal-A Systematic Review

Protein-bound uremic toxins (PBUTs) are associated with the progression of chronic kidney disease (CKD) and its associated morbidity and mortality. The conventional dialysis techniques are unable to efficiently remove PBUTs due to their plasma protein binding. Therefore, novel approaches are being developed, but these require validation in animals before clinical trials can begin. We conducted a systematic review to document PBUT concentrations in various models and species. The search strategy returned 1163 results for which abstracts were screened, resulting in 65 full-text papers for data extraction (rats (n = 41), mice (n = 17), dogs (n = 3), cats (n = 4), goats (n = 1), and pigs (n = 1)). We performed descriptive and comparative analyses on indoxyl sulfate (IS) concentrations in rats and mice. The data on large animals and on other PBUTs were too heterogeneous for pooled analysis. Most rodent studies reported mean uremic concentrations of plasma IS close to or within the range of those during kidney failure in humans, with the highest in tubular injury models in rats. Compared to nephron loss models in rats, a greater rise in plasma IS compared to creatinine was found in tubular injury models, suggesting tubular secretion was more affected than glomerular filtration. In summary, tubular injury rat models may be most relevant for the in vivo validation of novel PBUT-lowering strategies for kidney failure in humans.

Flaxseed Reduces Cancer Risk by Altering Bioenergetic Pathways in Liver: Connecting SAM Biosynthesis to Cellular Energy

This article illustrates how dietary flaxseed can be used to reduce cancer risk, specifically by attenuating obesity, type 2 diabetes, and non-alcoholic fatty liver disease (NAFLD). We utilize a targeted metabolomics dataset in combination with a reanalysis of past work to investigate the "metabo-bioenergetic" adaptations that occur in White Leghorn laying hens while consuming dietary flaxseed. Recently, we revealed how the anti-vitamin B6 effects of flaxseed augment one-carbon metabolism in a manner that accelerates S-adenosylmethionine (SAM) biosynthesis. Researchers recently showed that accelerated SAM biosynthesis activates the cell's master energy sensor, AMP-activated protein kinase (AMPK). Our paper provides evidence that flaxseed upregulates mitochondrial fatty acid oxidation and glycolysis in liver, concomitant with the attenuation of lipogenesis and polyamine biosynthesis. Defatted flaxseed likely functions as a metformin homologue by upregulating hepatic glucose uptake and pyruvate flux through the pyruvate dehydrogenase complex (PDC) in laying hens. In contrast, whole flaxseed appears to attenuate liver steatosis and body mass by modifying mitochondrial fatty acid oxidation and lipogenesis. Several acylcarnitine moieties indicate Randle cycle adaptations that protect mitochondria from metabolic overload when hens consume flaxseed. We also discuss a paradoxical finding whereby flaxseed induces the highest glycated hemoglobin percentage (HbA1c%) ever recorded in birds, and we suspect that hyperglycemia is not the cause. In conclusion, flaxseed modifies bioenergetic pathways to attenuate the risk of obesity, type 2 diabetes, and NAFLD, possibly downstream of SAM biosynthesis. These findings, if reproducible in humans, can be used to lower cancer risk within the general population.

A Review of the Potential Benefits of Herbal Medicines, Small Molecules of Natural Sources, and Supplements for Health Promotion in Lupus Conditions

The Latin word lupus, meaning wolf, was in the medical literature prior to the 1200s to describe skin lesions that devour flesh, and the resources available to physicians to help people were limited. The present text reviews the ethnobotanical and pharmacological aspects of medicinal plants and purified molecules from natural sources with efficacy against lupus conditions. Among these molecules are artemisinin and its derivatives, antroquinonol, baicalin, curcumin, emodin, mangiferin, salvianolic acid A, triptolide, the total glycosides of paeony (TGP), and other supplements such as fatty acids and vitamins. In addition, medicinal plants, herbal remedies, mushrooms, and fungi that have been investigated for their effects on different lupus conditions through clinical trials, in vivo, in vitro, or in silico studies are reviewed. A special emphasis was placed on clinical trials, active phytochemicals, and their mechanisms of action. This review can be helpful for researchers in designing new goal-oriented studies. It can also help practitioners gain insight into recent updates on supplements that might help patients suffering from lupus conditions.

The cardioprotective effects of secoisolariciresinol diglucoside (flaxseed lignan) against cafeteria diet-induced cardiac fibrosis and vascular injury in rats: an insight into apelin/AMPK/FOXO3a signaling pathways

Introduction: Fast food is a major risk factor for atherosclerosis, a leading cause of morbidity and mortality in the Western world. Apelin, the endogenous adipokine, can protect against cardiovascular disease via activating its receptor, APJ. Concurrently, secoisolariciresinol diglucoside (SDG), a flaxseed lignan extract (FLE), showed a therapeutic impact on atherosclerosis. The current study aimed to examine the effect of SDG on cafeteria diet (CAFD)-induced vascular injury and cardiac fibrosis via tracking the involvement of the apelin/APJ pathway. Methods: Thirty male rats were allocated into control, FLE-, CAFD-, CAFD/FLE-, and CAFD/FLE/F13A-treated rats, where F13A is an APJ blocker. All treatments lasted for 12 weeks. Results and discussion: The CAFD-induced cardiovascular injury was evidenced by histological distortions, dyslipidemia, elevated atherogenic indices, cardiac troponin I, collagen percentage, glycogen content, and apoptotic markers. CAFD increased both the gene and protein expression levels of cardiac APJ, apelin, and FOXO3a, in addition to increasing endothelin-1, VCAM1, and plasminogen activator inhibitor-1 serum levels and upregulating cardiac MMP-9 gene expression. Moreover, CAFD reduced serum paraoxonase 1 and nitric oxide levels, cardiac AMPK, and nuclear Nrf2 expression. FLE attenuated CAFD-induced cardiovascular injury. Such effect was reduced in rats receiving the APJ blocker, implicating the involvement of apelin/APJ in FLE protective mechanisms. Conclusion: FLE supplementation abrogated CAFD-induced cardiac injury and endothelial dysfunction in an apelin/APJ-dependent manner.

A diet supplemented with cholic acid elevates blood pressure accompanied by albuminuria in rats

A diet supplemented with cholic acid (CA), the primary 12α-hydroxylated bile acid, can induce hepatic lipid accumulation in rats without obesity. This study examined the effects of a CA-supplemented diet on blood pressure (BP). After acclimation, WKAH/HkmSlc rats (3 weeks old) were divided into two groups and fed with a control AIN-93-based diet or a CA-supplemented diet (0.5 g CA/kg) for 13 weeks. The CA diet increased systolic and diastolic BP as well as hepatic lipid concentrations in the rats. No changes were found in the blood sodium concentration. Urinary albumin concentration increased in CA-fed rats. An increase was observed in the hepatic expression of ATP-binding cassette subfamily B member 1B that correlated BPs and urinary albumin concentration accompanied by an increase in portal taurocholic acid concentration. These results suggest that 12α-hydroxylated bile acids are involved in increased BP and albuminuria via alteration of hepatic function.

Natural Products Against Renal Fibrosis via Modulation of SUMOylation

Renal fibrosis is the common and final pathological process of kidney diseases. As a dynamic and reversible post-translational modification, SUMOylation and deSUMOylation of transcriptional factors and key mediators significantly affect the development of renal fibrosis. Recent advances suggest that SUMOylation functions as the promising intervening target against renal fibrosis, and natural products prevent renal fibrosis via modulating SUMOylation. Here, we introduce the mechanism of SUMOylation in renal fibrosis and therapeutic effects of natural products. This process starts by summarizing the key mediators and enzymes during SUMOylation and deSUMOylation and its regulation role in transcriptional factors and key mediators in renal fibrosis, then linking the mechanism findings of SUMOylation and natural products to develop novel therapeutic candidates for treating renal fibrosis, and concludes by commenting on promising therapeutic targets and candidate natural products in renal fibrosis via modulating SUMOylation, which highlights modulating SUMOylation as a promising strategy for natural products against renal fibrosis.