Inhibition of Inflammatory Cytokine Expression Prevents High-Fat Diet-Induced Kidney Injury: Role of Lingonberry Supplementation

Natural compounds as obesity pharmacotherapies

Obesity has become a serious global public health problem, affecting over 988 million people worldwide. Nevertheless, current pharmacotherapies have proven inadequate. Natural compounds have garnered significant attention due to their potential antiobesity effects. Over the past three decades, ca. 50 natural compounds have been evaluated for the preventive and/or therapeutic effects on obesity in animals and humans. However, variations in the antiobesity efficacies among these natural compounds have been substantial, owing to differences in experimental designs, including variations in animal models, dosages, treatment durations, and administration methods. The feasibility of employing these natural compounds as pharmacotherapies for obesity remained uncertain. In this review, we systematically summarized the antiobesity efficacy and mechanisms of action of each natural compound in animal models. This comprehensive review furnishes valuable insights for the development of antiobesity medications based on natural compounds.

A Review of the Role of an Anthocyanin, Cyanidin-3-O-β-glucoside in Obesity-Related Complications

Obesity has become a major health issue worldwide and obese individuals possess higher levels of adipose tissue when compared with healthy individuals. Obesity is highly associated with the development of different chronic diseases, such as diabetes, cardiovascular diseases, hypertension, cancers, etc. Previous studies established that anthocyanin compounds play an important role in attenuating obesity-related consequences. Among various anthocyanin compounds, cyanidin-3-O-β-glucoside (C3G) is the most important component and is widely distributed in various colored edible plant materials, especially berries, cherries, black rice, purple corn, etc. In recent decades, several studies have reported the therapeutical properties of C3G. C3G has various biological properties and health benefits, such as antioxidant, antimicrobial, anti-inflammatory, antidiabetic, anti-obesity, neuroprotective, anticancer, etc. In this review, we summarized the in vitro and in vivo studies in relation to the role of C3G in obesity-related complications. Several mechanistic studies demonstrated that C3G maintains the metabolism of glucose, fatty acids, and lipids by regulating different genes and signaling pathways. It could be concluded that the consumption of C3G protects healthy individuals from obesity-related issues by maintaining body weight and regulating their metabolism and energy balance. This review provides some important signaling pathways/targets of C3G to facilitate the prevention and treatment of obesity, leading to the development of important food supplements.

N-(2-hydroxy phenyl) acetamide ameliorate inflammation and doxorubicin-induced nephrotoxicity in rats

Doxorubicin (DOX) is an anthracyclin antibiotic used for the treatment of various cancers. Nephrotoxicity is among the serious side effects of DOX, therefore, DOX-induced nephrotoxic model has been widely used to study nephropathies. The objectives of this study is to investigate the possible anti-inflammatory and nephroprotective effects of salicylic acid derivative, N-(2-hydroxy phenyl) acetamide (NA-2), in a rat model of DOX-induced nephrotoxicity. The in vitro anti-inflammatory potential of NA-2 was manifested by whole blood oxidative burst and nitric oxide (NO) assays with no toxicity on normal human fibroblast (BJ) cells, human embryonic kidney (HEK-293) cells, and normal monkey kidney epithelial (Vero) cells. The in vivo study included five groups: Normal control, DOX (6 mg/kg DOX-i.v.via tail vein), NA-2 treated control-i.p., NA-2/DOX treated-i.p., and prednisolone/DOX treated. After 7 days of DOX administration, rats with urinary protein level of >50 mg/kg/day were selected. Treatment group rats received i.p. doses of NA-2 (10 mg/kg/day) for 3 weeks with weekly monitoring of urinary protein excretion and body weights. mRNA expression of interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, monocyte chemoattractant protein (MCP)-1, and kidney injury molecule (KIM)-1 was analyzed by quantitative polymerase chain reaction (qPCR). Protein expressions were analyzed by immunohistochemistry. NA-2 attenuated DOX-induced changes in serum and urine levels, and improved inflammatory profile of the renal tissue. Histopathological findings revealed protective effects of NA-2 showing lesser lesions. We conclude that NA-2 is able to protect against DOX-induced renal damage functionally, biochemically and histopathologically with corresponding improvement in the kidney inflammatory profile.

The Role of Gender Differences and Menopause in Obesity-Related Renal Disease, Renal Inflammation and Lipotoxicity

The pathogenesis of obesity-related-renal disease is unknown. Menopause can promote renal disease in obese women, but this interaction is unclear. In a previous study, we observed that obese male and female mice developed albuminuria, hyperfiltration, and glomerulomegaly, and these changes were more severe in those obese ovariectomized females. In this study, we also evaluated renal inflammation and lipotoxicity in that animal model. For six months, 43 males and 36 females C57BL6/J mice were randomized to standard diet (SD) or high fat diet (HFD). A group of female animals on SD or HFD was ovariectomized to simulate menopause. We evaluated cytokines: NF-κβ p65, IL-1β, MCP-1, TNF-α, total lipid content, lipid classes, and fatty acid profile in total lipid and individual lipid classes in renal tissue and urine. We found that obese males and females showed higher NF-kβ p-65, TNF-α and MCP-1 in renal tissue, and obese females ovariectomized had higher IL-1β and TNF-α compared with not-ovariectomized. Also, obese animals showed lower proinflammatory and higher anti-inflammatory fatty acids in kidney total lipids, while obese females ovariectomized had a more exacerbated pattern. In brief, obesity induces inflammation and an unbalanced lipidic profile in renal tissue. This pattern seems to be enhanced in obesity after menopause.

Vaccinium as Potential Therapy for Diabetes and Microvascular Complications

Diabetes mellitus is one of the most critical global health concerns, with a fast-growing prevalence. The incidence of diabetic vascular complications is also rapidly increasing, exacerbating the burden on individuals with diabetes and the consumption of public medical resources. Despite the overall improvements in the prevention, diagnosis, and treatment of diabetic microvascular complications in recent years, safe and effective alternative or adjunctive therapies are urgently needed. The mechanisms underlying diabetic vascular complications are complex, with hyperglycemia-induced oxidative stress and inflammation being the leading causes. Therefore, glycemic control, antioxidation, and anti-inflammation are considered the main targets for the treatment of diabetes and its vascular comorbidities. Vaccinium L. (Ericaceae) is a genus of plants enriched with polyphenolic compounds in their leaves and fruits. Vaccinium and its extracts have demonstrated good bioactivity in reducing blood glucose, oxidative stress, and inflammation, making them excellent candidates for the management of diabetes and diabetic vascular complications. Here, we review recent preclinical and clinical studies on the potential effect of Vaccinium on ameliorating diabetes and diabetic complications, particularly diabetic kidney disease and diabetic retinopathy.

Anthocyanins ameliorate obesity-associated metainflammation: Preclinical and clinical evidence

The growing rates of obesity worldwide call for intervention strategies to help control the pathophysiological consequences of weight gain. The use of natural foods and bioactive compounds has been suggested as such a strategy because of their recognized antioxidant and anti-inflammatory properties. For example, polyphenols, especially anthocyanins, are candidates for managing obesity and its related metabolic disorders. Obesity is well known for the presence of metainflammation, which has been labeled as an inflammatory activation that leads to a variety of metabolic disorders, usually related to increased oxidative stress. Considering this, anthocyanins may be promising natural compounds able to modulate several intracellular mechanisms, mitigating oxidative stress and metainflammation. A wide variety of foods and extracts rich in anthocyanins have become the focus of research in the field of obesity. Here, we bring together the current knowledge regarding the use of anthocyanins as an intervention tested in vitro, in vivo, and in clinical trials to modulate metainflammation. Most recent research applies a wide variety of extracts and natural sources of anthocyanins, in diverse experimental models, which represents a limitation of the research field. However, the literature is sufficiently consistent to establish that the in-depth molecular analysis of gut microbiota, insulin signaling, TLR4-triggered inflammation, and oxidative stress pathways reveals their modulation by anthocyanins. These targets are interconnected at the cellular level and interact with one another, leading to obesity-associated metainflammation. Thus, the positive findings with anthocyanins observed in preclinical models might directly relate to the positive outcomes in clinical studies. In summary and based on the entirety of the relevant literature, anthocyanins can mitigate obesity-related perturbations in gut microbiota, insulin resistance, oxidative stress and inflammation and therefore may contribute as a therapeutic tool in people living with obesity.

Monkfish (Lophius litulon) Peptides Ameliorate High-Fat-Diet-Induced Nephrotoxicity by Reducing Oxidative Stress and Inflammation via Regulation of Intestinal Flora

BACKGROUND

Renal damage and intestinal flora imbalance due to lipotoxicity are particularly significant in terms of oxidative stress and inflammation, which can be alleviated with bioactive peptides. The monkfish (Lophius litulon) is rich in proteins, which can be used as a source of quality bioactive peptides. This study aimed to examine the protective effect of monkfish peptides on renal injury and their potential role in regulating gut microbiota.

METHODS

Monkfish meat was hydrolyzed using neutral protease and filtered, and the component with the highest elimination rate of 2,2-diphenyl-1-picrylhydrazyl was named lophius litulon peptides (LPs). Lipid nephrotoxicity was induced via high-fat diet (HFD) feeding for 8 weeks and then treated with LPs. Oxidative stress, inflammatory factors, and intestinal flora were evaluated.

RESULTS

LP (200 mg/kg) therapy reduced serum creatinine, uric acid, and blood urea nitrogen levels by 49.5%, 31.6%, and 31.6%, respectively. Renal vesicles and tubules were considerably improved with this treatment. Moreover, the activities of superoxide dismutase, glutathione peroxidase, and total antioxidant capacity increased significantly by 198.7%, 167.9%, 61.5%, and 89.4%, respectively. LPs attenuated the upregulation of HFD-induced Toll-like receptor 4 and phospho-nuclear factor-kappa B and increased the protein levels of heme oxygenase 1, nicotinamide quinone oxidoreductase 1, and nuclear factor erythroid 2-related factor 2. The dysbiosis of intestinal microbiota improved after LP treatment.

CONCLUSIONS

LPs significantly improve antioxidant activity, reduce inflammatory cytokine levels, and regulate intestinal dysbiosis. Thus, LPs are potential compounds that can alleviate HFD-induced renal lipotoxicity.

Phenotypic variation and epigenetic insight into tissue culture berry crops

Berry crops, a nutrient powerhouse for antioxidant properties, have long been enjoyed as a health-promoting delicious food. Significant progress has been achieved for the propagation of berry crops using tissue culture techniques. Although bioreactor micropropagation has been developed as a cost-effective propagation technology for berry crops, genetic stability can be a problem for commercial micropropagation that can be monitored at morphological, biochemical, and molecular levels. Somaclonal variations, both genetic and epigenetic, in tissue culture regenerants are influenced by different factors, such as donor genotype, explant type and origin, chimeral tissues, culture media type, concentration and combination of plant growth regulators, and culture conditions and period. Tissue culture regenerants in berry crops show increased vegetative growth, rhizome production, and berry yield, containing higher antioxidant activity in fruits and leaves that might be due to epigenetic variation. The present review provides an in-depth study on various aspects of phenotypic variation in micropropagated berry plants and the epigenetic effects on these variations along with the role of DNA methylation, to fill the existing gap in literature.

Inhibitory effect of lingonberry extract on HepG2 cell proliferation, apoptosis, migration, and invasion

Lingonberry (Vaccinium vitis-idaea L.) extract contains various active ingredients with strong inhibitory effects on cancer cell growth. HepG2 cells were treated with various concentrations of lingonberry extract, cell inhibition rate was measured by CCK-8 assay, and apoptosis rate by annexin-propidium iodide double-staining assay. The cell cycle was analyzed by flow cytometry, and cell migration and invasion by transwell assay. Real-time reverse transcription-PCR and western blotting were employed to analyze the expression of C-X-C motif chemokine ligand 3 (CXCL3). Ki-67, TUNEL, and transwell assays were used to verify the relationship between CXCL3 expression and cell proliferation, apoptosis, migration, and invasion. The composition of lingonberry extract was: 37.58% cyanidin-3-O-glucoside, 10.96% kaempferol 3-O-arabinoside, 4.52% epicatechin, 4.35% chlorogenic acid, 3.83% catechinic acid, 1.54% isoquercitrin, 1.05% 4-hydroxycinnamon acid, 1.03% cyanidin chloride, 0.85% 2,3-dihydroxybenzoic acid, 0.55% quercetin, 0.36% D-(-)-quininic acid, 0.96% caffeic acid, 0.16% ferulic acid, 0.12% oleanolic acid, and 0.03% ursolic acid. Lingonberry extract inhibited the proliferation of HepG2 cells in a dose-dependent manner. After 48 h exposure to 100 μg/mL extract the inhibition rate and IC₅₀ were 80.89±6.05% and 22.62 μg/mL, respectively. Lingonberry extract promoted late apoptosis in HepG2 cells and arrested the cell cycle at G2/M and S phases. Lingonberry extract also promoted the apoptosis of HepG2 cancer cells, inhibiting their proliferation, migration, and invasion by regulating the expression of CXCL3. This study offers new insight into the antihepatoma activity of lingonberry extract and provides a basis for the development of pilot antitumor drugs.

Lingonberry Improves Hepatic Lipid Metabolism by Targeting Notch1 Signaling

Impaired hepatic lipid metabolism is a hallmark of non-alcoholic fatty liver disease (NAFLD), which has no effective treatment option. Recently, Notch signaling has been identified as an important mediator of hepatic lipid metabolism. Lingonberry (Vaccinium vitis-idaea L.) is an anthocyanin-rich fruit with significant lipid-lowering properties. In this study, we examined how lingonberry influenced Notch signaling and fatty acid metabolism in a mouse model of NAFLD. Mice (C57BL/6J) fed a high-fat diet (HFD) for 12 weeks developed fatty liver and activated hepatic Notch1 signaling. Lingonberry supplementation inhibited hepatic Notch1 signaling and improved lipid profile by improving the expression of the genes involved in hepatic lipid metabolism. The results were verified using a palmitic-acid-challenged cell model. Similar to the animal data, palmitic acid impaired cellular lipid metabolism and induced Notch1 in HepG2 cells. Lingonberry extract or cyanidin-3-glucoside attenuated Notch1 signaling and decreased intracellular triglyceride accumulation. The inhibition of Notch in the hepatocytes attenuated sterol-regulatory-element-binding-transcription-factor-1 (SREBP-1c)-mediated lipogenesis and increased the expression of carnitine palmitoyltransferase-I-alpha (CPTIα) and acyl-CoA oxidase1 (ACOX1). Taken together, lingonberry’s hepatoprotective effect is mediated by, in part, improving hepatic lipid metabolism via inhibiting Notch1 signaling in HFD-induced fatty liver.

High-Fat Diet-Induced Renal Proximal Tubular Inflammatory Injury: Emerging Risk Factor of Chronic Kidney Disease

Nowadays, with the improvements in living standards and changes in living habits, high-fat diet (HFD) has become much more common in the populations worldwide. Recent studies have shown that HFD could induce lipid accumulation, and structural and functional abnormalities, accompanied by the release of large amounts of pro-inflammatory cytokines, in proximal tubular epithelial cells (PTECs). These findings indicate that, as an emerging risk factor, PTEC injury-induced by HFD may be closely related to inflammation; however, the potential mechanisms underlying this phenomenon is still not well-known, but may involve the several inflammatory pathways, including oxidative stress-related signaling pathways, mitochondrial dysfunction, the myeloid differentiation factor 2/Toll like receptor 4 (MD2/TLR4) signaling pathway, the ERK1/2-kidney injury molecule 1 (KIM-1)-related pathway, and nuclear factor-κB (NF-κB) activation, etc., and the detailed molecular mechanisms underlying these pathways still need further investigated in the future. Based on lipid abnormalities-induced inflammation is closely related to the development and progression of chronic kidney disease (CKD), to summarize the potential mechanisms underlying HFD-induced renal proximal tubular inflammatory injury, may provide novel approaches for CKD treatment.

In vitro assessment of the cytotoxicity and anti-inflammatory properties of a novel dietary supplement

Studies on the immunopharmacological activities of various plant species have provided evidence for the high therapeutic potential of different extracts. These represent a promising alternative to reduce the inflammatory processes and, thus, diseases related to inflammation. Numerous scientific studies strongly suggest that diet plays an essential role in inflammation, and that certain dietary factors can act as preventive or treatment methods to lower inflammation. In the present study, a novel lingonberry-based dietary supplement was investigated for the ability to suppress the inflammatory response in activated monocytes/macrophages. Based on cell viability/proliferation and cytotoxicity tests, concentrations between 40 and 130 µg/ml of the extracts showed a high viability/proliferation effect and no cytotoxic activity in monocyte/macrophage cells. To further investigate the anti-inflammatory potential of our novel lingonberry-based dietary supplement, we studied the effect of the extract on the inflammatory response in lipopolysaccharide (LPS)-stimulated macrophages. We found that the extract exhibited a strong anti-inflammatory potential by inhibiting the expression of major inflammatory cytokines [interleukin (IL)-6, IL-8 and tumor necrosis factor (TNF)α] in activated monocyte/macrophage cells. The expression of IL-6 and IL-8 was subsequently validated by enzyme-linked immunosorbent assay (ELISA). In conclusion, we demonstrated that our product exhibits no cytotoxicity and suppresses inflammation, and thus can be considered a natural important tool for inflammation control.

The Therapeutic Strategies for Uremic Toxins Control in Chronic Kidney Disease

Uremic toxins (UTs) are mainly produced by protein metabolized by the intestinal microbiota and converted in the liver or by mitochondria or other enzymes. The accumulation of UTs can damage the intestinal barrier integrity and cause vascular damage and progressive kidney damage. Together, these factors lead to metabolic imbalances, which in turn increase oxidative stress and inflammation and then produce uremia that affects many organs and causes diseases including renal fibrosis, vascular disease, and renal osteodystrophy. This article is based on the theory of the intestinal-renal axis, from bench to bedside, and it discusses nonextracorporeal therapies for UTs, which are classified into three categories: medication, diet and supplement therapy, and complementary and alternative medicine (CAM) and other therapies. The effects of medications such as AST-120 and meclofenamate are described. Diet and supplement therapies include plant-based diet, very low-protein diet, probiotics, prebiotics, synbiotics, and nutraceuticals. The research status of Chinese herbal medicine is discussed for CAM and other therapies. This review can provide some treatment recommendations for the reduction of UTs in patients with chronic kidney disease.

Lingonberry Improves Non-Alcoholic Fatty Liver Disease by Reducing Hepatic Lipid Accumulation, Oxidative Stress and Inflammatory Response

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease globally and there is a pressing need for effective treatment. Lipotoxicity and oxidative stress are the important mediators in NAFLD pathogenesis. Lingonberry (Vaccinium vitis-idaea L.) is rich in anthocyanins that have antioxidant and anti-inflammatory properties. The present study investigated the effect of lingonberry supplementation on liver injury in C57BL/6J male mice fed a high-fat diet (HFD) for 12 weeks. Mice fed HFD displayed liver injury with steatosis, increased lipid peroxidation and inflammatory cytokine expression in the liver as compared to mice fed a control diet. Lingonberry supplementation for 12 weeks alleviated HFD-induced liver injury, attenuated hepatic lipid accumulation, and inflammatory cytokine expression. Lingonberry supplementation inhibited the expression of sterol regulatory element-binding protein-1c (SREBP-1c) and acetyl-CoA carboxylase-1 (AAC-1) as well as activated AMP-activated protein kinase (AMPK) in the liver. It also decreased HFD-induced hepatic oxidative stress and aggregation of inflammatory foci. This was associated with a restoration of nuclear factor erythroid 2-related factor 2 (Nrf2) and glutathione level in the liver. These results suggest that lingonberry supplementation can protect against HFD-induced liver injury partly through attenuation of hepatic lipid accumulation, oxidative stress, and inflammatory response.

Obesity-like metabolic effects of high-carbohydrate or high-fat diets consumption in metabolic and renal functions

Present study investigated which diet, high-carbohydrate (HCD) or high-fat (HFD), most effectively induces classical characteristics of obesity in mice. Mice were fed commercial chow (control), an HCD, or an HFD for 12 weeks. HFD and HCD increased body weight, fat mass, and glycaemia, whereas the HFD augmented insulinemia. In the kidney, the HFD caused albuminuria, and reductions in fractional Na⁺ excretion, Thromboxane B2 (TXB2) excretion, and urinary flow, whereas the HCD reduced glomerular filtration, plasma osmolality, and TXB2 and Prostaglandin E2 excretion. The consumption of HFD and HCD modified parameters that indicate histopathological changes, such as proliferation (proliferating-cell-nuclear antigen), inflammation (c-Jun N-terminal-protein), and epithelial-mesenchymal transition (vimentin, and desmin) in renal tissue, but the HCD group presents fewer signals of glomerular hypertrophy or tubule degeneration. In summary, the HCD generated the metabolic and renal changes required for an obesity model, but with a delay in the development of these modifications concerning the HFD.