Xanthohumol protects against renal ischaemia reperfusion (I/R) injury by scavenging ROS and inhibition of JAK-2/STAT-3 inflammatory pathway

Exploring the glycation association with dyslipidaemia: Novel approach for diabetic nephropathy

The transcription factor known as sterol regulatory element-binding protein (SREBP) and the glycation pathways, specifically the formation of Advanced Glycation End Products (AGEs), have a significant and deleterious impact on the kidney. They alter renal lipid metabolism and promote glomerulosclerosis, mesangial cell expansion, tubulointerstitial fibrosis, and inflammation, leading to diabetic nephropathy (DN) progression. Although several pieces of scientific evidence are reported for potential causes of glycation and lipotoxicity in DN, the underlying mechanism of renal lipid accumulation still needs to be fully understood. We provide a rationalized view on how AGEs exert multiple effects that cause SREBP activation and inflammation, contributing to DN through Receptor for AGEs (RAGE) signaling, AGE-R1-dependent downregulation of Sirtuin 1 (SIRT-1), and increased SREBP Cleavage Activating Protein (SCAP) glycosylation. This review emphasizes the association between glycation and the SREBP pathway and how it affects the onset of DN associated with obesity. Finally, we discuss the correlation of glycation and the SREBP pathway with insulin resistance (IR), oxidative stress, endoplasmic reticulum stress, inflammation, and existing and emerging therapeutic approaches toward better controlling obesity-related DN.

The Hepatic Antisteatosis Effect of Xanthohumol in High-Fat Diet-Fed Rats Entails Activation of AMPK as a Possible Protective Mechanism

Obesity is the leading cause of non-alcoholic fatty liver disease by provoking hyperglycemia, hyperlipidemia, insulin resistance, oxidative stress, and inflammation. Low activity of AMP-activated protein kinase (AMPK) is linked to obesity, liver injury, and NAFLD. This study involves examining if the anti-steatosis effect of Xanthohumol (XH) in high-fat diet (HFD)-fed rats involves the regulation of AMPK. Adult male rats were divided into five groups (n = 8 each) as control (3.85 kcal/g); XH (control diet + 20 mg/kg), HFD (4.73 kcl/g), HFD + XH (20 mg/kg), and HFD + XH (30 mg/kg) + compound c (cc) (0.2 mg/kg). All treatments were conducted for 12 weeks. Treatment with XH attenuated the gain in body weight, fat pads, fasting glucose, and insulin in HFD rats. It also lowered serum leptin and free fatty acids (FFAs) and improved glucose and insulin tolerances in these rats. It also attenuated the increase in serum livers of liver marker enzymes and reduced serum and hepatic levels of triglycerides (TGs), cholesterol (CHOL), FFAs, as well as serum levels of low-density lipoproteins cholesterol (LDL-c) oxidized LDL-c. XH also reduced hepatic levels of malondialdehyde (MDA), nuclear accumulation of NF-κB, and the levels of tumor necrosis-factor-α (TNF-α) and interleukin-6 (IL-6) while stimulating the nuclear levels of Nrf2 and total levels of glutathione (GSH), superoxide dismutase (SOD), and catalase (CAT) in these HFD-fed rats. At the molecular levels, XH increased hepatic mRNA expression and phosphorylation of AMPK (Thr72) and reduced the expression of lipogenic genes SREBP1c and ACC-1. In concomitance, XH reduced hepatic liver droplet accumulation, reduced the number of apoptotic nuclei, and improved the structures of nuclei, mitochondria, and rough endoplasmic reticulum. Co-treatment with CC, an AMPK inhibitor, completely abolished all these effects of XH. In conclusion, XH attenuates obesity and HFD-mediated hepatic steatosis by activating hepatic AMPK.

Use of Lipid-Modifying Agents for the Treatment of Glomerular Diseases

Although dyslipidemia is associated with chronic kidney disease (CKD), it is more common in nephrotic syndrome (NS), and guidelines for the management of hyperlipidemia in NS are largely opinion-based. In addition to the role of circulating lipids, an increasing number of studies suggest that intrarenal lipids contribute to the progression of glomerular diseases, indicating that proteinuric kidney diseases may be a form of "fatty kidney disease" and that reducing intracellular lipids could represent a new therapeutic approach to slow the progression of CKD. In this review, we summarize recent progress made in the utilization of lipid-modifying agents to lower renal parenchymal lipid accumulation and to prevent or reduce kidney injury. The agents mentioned in this review are categorized according to their specific targets, but they may also regulate other lipid-relevant pathways.

The Preventive Effects of Xanthohumol on Vascular Calcification Induced by Vitamin D3 Plus Nicotine

Vascular calcification (VC) is highly prevalent in patients with atherosclerosis, chronic kidney disease, diabetes mellitus, and hypertension. In blood vessels, VC is associated with major adverse cardiovascular events. Xanthohumol (XN), a main prenylated chalcone found in hops, has antioxidant effects to inhibit VC. This study aimed to investigate whether XN attenuates VC through in vivo study. A rat VC model was established by four weeks oral administration of vitamin D₃ plus nicotine in Sprague Dawley (SD) rats. In brief, 30 male SD rats were randomly divided into three groups: control, 25 mg/kg nicotine in 5 mL corn oil and 3 × 10⁵ IU/kg vitamin D₃ administration (VDN), and combination of VDN with 20 mg/L in 0.1% ethanol of XN (treatment group). Physiological variables such as body and heart weight and drinking consumption were weekly observed, and treatment with XN caused no differences among the groups. In comparison with the control group, calcium content and alkaline phosphatase (ALP) activity were increased in calcified arteries, and XN treatment reduced these levels. Dihydroethidium (DHE) and 2′,7′-dichloroflurescin diacetate (DCFH-DA) staining to identify Superoxide and reactive oxygen species generation from aorta tissue showed increased production in VDN group compared with the control and treatment groups. Hematoxylin eosin (HE) and Alizarin Red S staining were determined to show medial vascular thickness and calcification of vessel wall. Administration of VDN resulted in VC, and XN treatment showed improvement in vascular structure. Moreover, overexpression of osteogenic transcription factors bone morphogenetic protein 2 (BMP-2) and runt-related transcription factor 2 (Runx2) were significantly suppressed by XN treatment in VC. Moreover, downregulation of vascular phenotypic markers alpha-smooth muscle actin (α-SMA) and smooth muscle 22 alpha (SM22α) were increased by XN treatment in VC. Furthermore, XN treatment in VC upregulated nuclear translocation of nuclear factor-E2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) expressions. Otherwise, Kelch-like ECH-associated protein 1 (Keap1) was alleviated by XN treatment in VC. In conclusion, our findings suggested that XN enhances antioxidant capacity to improve VC by regulating the Nrf2/Keap1/HO-1 pathway. Therefore, XN may have potential effects to decrease cardiovascular risk by reducing VC.

Salidroside ameliorates diabetic nephropathy in rats by activating renal AMPK/SIRT1 signaling pathway

This study investigated if the nephroprotective effect of Salidroside T1DM rats involves activation of AMPK/SIRT1. Rats were divided into control or T1DM and treated with vehicle or Salidroside (100 mg/kg) for 56 days. Mesangial cells were cultured in LG or HG media with or without Salidroside (100 µM/L) for 24 hr. Also, HG + Salidroside-treated cells were pre-incubated with EX-527 or compound C (CC) for 1 hr. With reducing glucose levels, Salidroside improved kidney structure/function in the T1DM rat. It also increased GSH and Bcl-2 levels in control and T1DM rats and inhibited ROS, increased activation of AMPK and nuclear SIRT1, and lowered acetylation of P53 and FOXO-1 in control and T1DM rats and in LG and HG-treated cells. These effects were abolished by EX-527 and CC. Also, CC decreased the nuclear levels of SIRT1. In conclusion, Salidroside attenuates DN in T1DM rats by activation of AMPK and subsequently, SIRT1. PRACTICAL APPLICATIONS: This animal and pre-clinical study shows that Salidroside is able to ameliorate DN in T1DM-induced rats and showed that it mainly acts by a hypoglycemic effect and activation of renal AMPK/SIRT1 axis. Given the wide tissue stimulatory effect of AMPK on peripheral glucose utilization, lipogenesis, and other cell signaling pathways, these data are encouraging to investigate the anti-diabetic effect of glycoside in more clinical trials.