Low-dose phloretin alleviates diabetic atherosclerosis through endothelial KLF2 restoration

A Review of Experimental Studies on Natural Chalcone-Based Therapeutic Targeting of Genes and Signaling Pathways in Type 2 Diabetes Complications

Diabetes mellitus type 2 (T2DM) is a common chronic condition that presents as unsettled hyperglycemia (HG) and results from insulin resistance (IR) and β-cell dysfunction. T2DM is marked by an increased risk of microvascular and macrovascular complications, all of which can be the cause of increasing mortality. Diabetic nephropathy (DNE), neuropathy (DNU), and retinopathy (DR) are the most common complications of diabetic microangiopathy, while diabetic cardiomyopathy (DCM) and peripheral vascular diseases are the major diabetic macroangiopathy complications. Chalcones (CHs) are in the flavonoid family and are commonly found in certain plant species as intermediate metabolites in the biosynthesis of flavonoids and their derivatives. Natural CHs with different substituents exert diverse therapeutic activities, including antidiabetic ones. However, the therapeutic mechanisms of natural CHs through influencing genes and/or signaling pathways in T2DM complications remain unknown. Therefore, this review summarizes the existing results from experimental models which highlight the mechanisms of natural CHs as therapeutic agents for T2DM complications.

Unveiling the oral-gut connection: chronic apical periodontitis accelerates atherosclerosis via gut microbiota dysbiosis and altered metabolites in apoE-/- Mice on a high-fat diet

The aim of this study was to explore the impact of chronic apical periodontitis (CAP) on atherosclerosis in apoE-/- mice fed high-fat diet (HFD). This investigation focused on the gut microbiota, metabolites, and intestinal barrier function to uncover potential links between oral health and cardiovascular disease (CVD). In this study, CAP was shown to exacerbate atherosclerosis in HFD-fed apoE-/- mice, as evidenced by the increase in plaque size and volume in the aortic walls observed via Oil Red O staining. 16S rRNA sequencing revealed significant alterations in the gut microbiota, with harmful bacterial species thriving while beneficial species declining. Metabolomic profiling indicated disruptions in lipid metabolism and primary bile acid synthesis, leading to elevated levels of taurochenodeoxycholic acid (TCDCA), taurocholic acid (TCA), and tauroursodeoxycholic acid (TDCA). These metabolic shifts may contribute to atherosclerosis development. Furthermore, impaired intestinal barrier function, characterized by reduced mucin expression and disrupted tight junction proteins, was observed. The increased intestinal permeability observed was positively correlated with the severity of atherosclerotic lesions, highlighting the importance of the intestinal barrier in cardiovascular health. In conclusion, this research underscores the intricate interplay among oral health, gut microbiota composition, metabolite profiles, and CVD incidence. These findings emphasize the importance of maintaining good oral hygiene as a potential preventive measure against cardiovascular issues, as well as the need for further investigations into the intricate mechanisms linking oral health, gut microbiota, and metabolic pathways in CVD development.

Phloretin alleviates palmitic acid-induced oxidative stress in HUVEC cells by suppressing the expression of LncBAG6-AS

Oxidative stress (OS) is an important trigger of vascular endothelial injury (VEI), which then leads to cardiovascular disease (CVDs). Phloretin was previously investigated to alleviate OS in human umbilical vein endothelial cells (HUVECs) by activating the AMPK/Nrf2 pathway; however, whether phloretin exerts cardiovascular health benefits by targeting non-coding RNAs (ncRNAs) remains unclear. Herein, the whole transcriptome sequencing and lncRNA library building were performed on HUVECs, a commonly used cell line for CVDs study, from different groups in control (CK), palmitic acid (PA, 100 μM), and PA + phloretin (50 μM, G50). KEGG analysis demonstrated that DE-lncRNAs regulated the pathway related to OS and metabolism in HUVECs. LncBAG6-AS was highly expressed under OS stimulation, which was reversed by phloretin co-treatment. Moreover, the MMP, activities of SOD, GSH-Px, T-AOC and GR were significantly ameliorated after interference of LncBAG6-AS, which were consistent with phloretin recover group. Furthermore, the expression of DE-genes from previously reported mRNA sequencing, including MAPK10, PIK3R1, ATP2B4, AKT2, and ADCY9, were significantly changed with LncBAG6-AS interference, indicating that LncBAG6-AS may participate in the process of OS attenuation by phloretin through regulating gene expression. So, the transcriptome sequencing of HUVECs with LncBAG6-AS knockdown was subsequently performed and DE-genes for "NC vs. si-ASO-LncBAG6-AS" were significantly enriched with GO terms, such as apoptosis, response to OS, ferroptosis, and others, which were similar to those observed from KEGG analysis. Overall, this study provides new insights into the molecular mechanisms by which bioactive substances alleviate OS and potential targets for the early prevention and treatment of VEI.

Phloretin Transfersomes for Transdermal Delivery: Design, Optimization, and In Vivo Evaluation

BACKGROUND

Phloretin (Phl) is a flavonoid compound that contains multiple phenolic hydroxyl groups. It is found in many plants, such as apple leaves, lychee pericarp, and begonia, and has various biological activities, such as antioxidant and anticancer effects. The strong hydrogen bonding between Phl molecules results in poor water solubility and low bioavailability, and thus the scope of the clinical application of Phl is limited. Therefore, it is particularly important to improve the water solubility of Phl for its use to further combat or alleviate skin aging and oxidative damage and develop antioxidant products for the skin. The purpose of this study was to develop and evaluate a phloretin transfersome gel (PTG) preparation for transdermal drug delivery to improve the bioavailability of the drug and delay aging.

METHODS

Phloretin transfersomes (Phl-TFs) were prepared and optimized by the thin-film dispersion-ultrasonication method. Phl-TFs were characterized by transmission electron microscopy (TEM), differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectroscopy, and X-ray diffraction (XRD). The Log P method was used to determine the solubility of the Phl-TFs. The skin penetration ability of the prepared PTG was evaluated using the Franz diffusion cell method. In addition, the in vivo pharmacokinetics of PTG were studied in rats, and an antioxidant activity investigation was conducted using a D-gal rat model.

RESULTS

Phl-TFs were successfully prepared with a Soybean Phosphatidylcholine (SPC)/CHOL ratio of 2.7:1 w/v, a phloretin concentration of 1.3 mg/mL, a hydration time of 46 min, an ultrasound time of 5 min, and an ultrasound power of 180 W. The Log P was 2.26, which was significantly higher than that of phloretin (p < 0.05, paired t test). The results of the in vitro penetration test demonstrated that the cumulative skin penetration of the Phl-TFs after 24 h was 842.73 ± 20.86 μg/cm2. The data from an in vivo pharmacokinetic study showed that the Cmax and AUC of PTG were 1.39- and 1.97-fold higher than those of the phloretin solution gel (PSG), respectively (p < 0.05, paired t test). The experimental results in aging rats showed that PTG had a better antioxidant effect.

CONCLUSIONS

Phl-TFs and PTG preparations with a good shape, safety, and stability were successfully prepared. In vivo pharmacokinetics and preliminary antioxidant experiments further verified the transdermal penetration and antioxidant activity of the phloretin transdermal drug delivery preparation, providing an experimental basis for its further development.

Differentiated serum levels of Krüppel-like factors 2 and 4, sP-selectin, and sE-selectin in patients with gestational diabetes mellitus

OBJECTIVES

This study aims to determine serum levels of human Krüppel-like factors (KLFs), sP-selectin and sE-selectin and establish correlations between them in patients with gestational diabetes mellitus (GDM).

METHODS

Twenty-six GDM patients aged between 22 and 35 years and 25 healthy pregnant women aged between 23 and 34 years were recruited. Maternal serum levels of KLF2, KLF4, and their target proteins sP-selectin, sE-selectin were measured using enzyme-linked immunosorbent assays at 24-28 weeks of gestation.

RESULTS

Women with GDM had significantly lower serum KLF2 than controls. However, the differences in levels of serum KLF4 between the control and GDM groups were not significant. Additionally, elevated serum sP-selectin and sE-selectin were found in the GDM group and not in the healthy group. Importantly, we also found that serum KLF2 levels were negatively correlated with indicators of glucose metabolism, including insulin, fasting blood glucose, 1-h oral glucose tolerance test, and glycated hemoglobin.

CONCLUSION

We conclude that (i) serum KLF2 might be indicative of GDM risk, and (ii) sP-selectin and sE-selectin were increased in GDM patients.

Effects of natural dihydrochalcones in sweet tea (Lithocarpus polystachyus) on diabetes: a systematical review and meta-analysis of animal studies

Sweet tea (Lithocarpus polystachyus Rehd.), a natural functional food highly rich in dihydrochalcones including trilobatin, phlorizin and phloretin, is reported to possess numerous biological activities especially for treating diabetes. Here, the aim of this systematical review and meta-analysis is to assess the effect of dihydrochalcones in sweet tea (DST) on diabetes and summarize their possible mechanisms. We searched in eight databases including Embase, PubMed, Cochrane, Web of Science, WanFang database, VIP database, China National Knowledge Infrastructure and China Biology Medicine from Jan 2000 to Nov 2021 and ultimately included 21 animal studies in this review. A total of 10 outcome measurements including blood lipid indexes, blood glucose, insulin resistance indicators and oxidative stress biomarkers were extracted for meta-analysis using RevMan 5.4 software. DST significantly decreased the levels of triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-c), blood glucose (BG), homeostasis model assessment of insulin resistance (HOMA-IR) and malondialdehyde (MDA), and increased high-density lipoprotein cholesterol (HDL-c), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activity in diabetic animal models. In summary, DST could treat diabetes by regulation of blood glucose/lipid metabolism, oxidative/carbonyl stress, inflammatory response etc.

Natural Flavonoids Derived From Fruits Are Potential Agents Against Atherosclerosis

Atherosclerosis, as a chronic inflammatory response, is one of the main causes of cardiovascular diseases. Atherosclerosis is induced by endothelial cell dysfunction, migration and proliferation of smooth muscle cells, accumulation of foam cells and inflammatory response, resulting in plaque accumulation, narrowing and hardening of the artery wall, and ultimately leading to myocardial infarction or sudden death and other serious consequences. Flavonoid is a kind of natural polyphenol compound widely existing in fruits with various structures, mainly including flavonols, flavones, flavanones, flavanols, anthocyanins, isoflavones, and chalcone, etc. Because of its potential health benefits, it is now used in supplements, cosmetics and medicines, and researchers are increasingly paying attention to its role in atherosclerosis. In this paper, we will focus on several important nodes in the development of atherosclerotic disease, including endothelial cell dysfunction, smooth muscle cell migration and proliferation, foam cell accumulation and inflammatory response. At the same time, through the classification of flavonoids from fruits, the role and potential mechanism of flavonoids in atherosclerosis were reviewed, providing a certain direction for the development of fruit flavonoids in the treatment of atherosclerosis drugs.

The Role of KLF2 in the Regulation of Atherosclerosis Development and Potential Use of KLF2-Targeted Therapy

Kruppel like factor 2 (KLF2) is a mechanosensitive transcription factor participating in the regulation of vascular endothelial cells metabolism. Activating KLF2 in endothelial cells induces eNOS (endothelial nitric oxide synthase) expression, subsequent NO (nitric oxide) release, and vasodilatory effect. In addition, many KLF2-regulated genes participate in the anti-thrombotic, antioxidant, and anti-inflammatory activities, thereby preventing atherosclerosis development and progression. In this review, we summarise recent evidence suggesting that KLF2 plays a major role in regulating atheroprotective effects in endothelial cells. We also discuss several recently identified repurposed drugs and natural plant-based bioactive compounds with KLF2-mediated atheroprotective activities. Herein, we present a comprehensive overview of the role of KLF2 in atherosclerosis and as a pharmacological target for different drugs and natural compounds and highlight the potential application of these phytochemicals for the treatment of atherosclerosis.

Omnifarious fruit polyphenols: an omnipotent strategy to prevent and intervene diabetes and related complication?

Diabetes mellitus is a metabolic syndrome which cannot be cured. Recently, considerable interest has been focused on food ingredients to prevent and intervene in complications of diabetes. Polyphenolic compounds are one of the bioactive phytochemical constituents with various biological activities, which have drawn increasing interest in human health. Fruits are part of the polyphenol sources in daily food consumption. Fruit-derived polyphenols possess the anti-diabetic activity that has already been proved either from in vitro studies or in vivo studies. The mechanisms of fruit polyphenols in treating diabetes and related complications are under discussion. This is a comprehensive review on polyphenols from the edible parts of fruits, including those from citrus, berries, apples, cherries, mangoes, mangosteens, pomegranates, and other fruits regarding their potential benefits in preventing and treating diabetes mellitus. The signal pathways of characteristic polyphenols derived from fruits in reducing high blood glucose and intervening hyperglycemia-induced diabetic complications were summarized.