Folate Deficiency Enhanced Inflammation and Exacerbated Renal Fibrosis in High-Fat High-Fructose Diet-Fed Mice

The prevalence of obesity and chronic kidney disease (CKD) is increasing simultaneously and rapidly worldwide. Our previous study showed that folate deficiency increased lipid accumulation and leptin production of adipocytes. Whether folate plays a role in CKD, particularly obesity-related nephropathy remains unclear. To investigate the effects of folate deficiency on CKD in diet-induced obese mice, four groups of male C57BL/6 mice were fed either a normal-fat diet (NF) with folate (NF+f); NF without folate (NF-f); high-fat high-fructose diet (HFF) with folate (HFF+f); or HFF without folate (HFF-f) for 12 months during the study. The results showed that HFF increased not only body weight, fasting blood glucose, total cholesterol (TC), low-density lipoprotein (LDL)-cholesterol, and blood pressure, but also cytokines levels, such as interleukin (IL)-2, interferon (IFN)-γ, IL-17A/F, IL-6, monocyte chemoattractant protein (MCP)-1, and transforming growth factor (TGF)-β1. The indicators of kidney failure including urinary protein, neutrophil gelatinase-associated lipocalin (NGAL), renal type I and IV collagen deposits and leptin content, and serum creatinine were also increased by HFF. Folate-deficient diets further elevated serum TC, LDL-cholesterol, IL-6, tumor necrosis factor (TNF)-α, MCP-1, TGF-β1, and leptin, but decreased IL-10 level, and thus exacerbated renal fibrosis. To investigate the possible mechanisms of folate deficiency on renal injury, phosphorylation of pro-fibrosis signaling molecules, including signal transducer and activator of transcription (STAT)3 and small mothers against decapentaplegic (Smad)2/3, were assayed. Both HFF and folate deficiency significantly increased the phosphorylation of STAT3 and Smad2/3, suggesting synergistic effects of HFF-f on chronic renal inflammation and fibrosis. In conclusion, the results demonstrated that folate deficiency might aggravate inflammatory status and enhance renal fibrosis.

Protective effect of natural products in the metabolic-associated kidney diseases via regulating mitochondrial dysfunction

Metabolic syndrome (MS) is a complex group of metabolic disorders syndrome with hypertension, hyperuricemia and disorders of glucose or lipid metabolism. As an important organ involved in metabolism, the kidney is inevitably attacked by various metabolic disorders, leading to abnormalities in kidney structure and function. Recently, an increasing number of studies have shown that mitochondrial dysfunction is actively involved in the development of metabolic-associated kidney diseases. Mitochondrial dysfunction can be used as a potential therapeutic strategy for the treatment of metabolic-associated kidney diseases. Many natural products have been widely used to improve the treatment of metabolic-associated kidney diseases by inhibiting mitochondrial dysfunction. In this paper, by searching several authoritative databases such as PubMed, Web of Science, Wiley Online Library, and Springer Link. We summarize the Natural Products Protect Against Metabolic-Associated Kidney Diseases by Regulating Mitochondrial Dysfunction. In this review, we sought to provide an overview of the mechanisms by which mitochondrial dysfunction impaired metabolic-associated kidney diseases, with particular attention to the role of mitochondrial dysfunction in diabetic nephropathy, gouty nephropathy, hypertensive kidney disease, and obesity-related nephropathy, and then the protective role of natural products in the kidney through inhibition of mitochondrial disorders, thus providing a systematic understanding of the targets of mitochondrial dysfunction in metabolic-associated kidney diseases, and finally a review of promising therapeutic targets and herbal candidates for metabolic-associated kidney diseases through inhibition of mitochondrial dysfunction.

A Perihilar Variant of Focal Segmental Glomerulosclerosis Due to De novo Branchio-oto-renal Syndrome

Branchio-oto-renal syndrome is an autosomal dominant disorder characterized by branchial anomalies, hearing loss, and renal urinary tract malformations. We herein report a 32-year-old Japanese man with a right preauricular pit, bilateral mixed hearing loss, and malposition of the right kidney who presented with proteinuria. The findings of a left kidney biopsy were compatible with a perihilar variant of secondary focal segmental glomerular sclerosis. A trio exome analysis conducted among the patient and his parents failed to identify the causal gene variant, despite a sporadic pattern. His kidney function remained stable for 11 years with an angiotensin II receptor blocker.

The Astragaloside IV Derivative LS-102 Ameliorates Obesity-Related Nephropathy

Background

Astragaloside IV is the most important bioactive component of Radix Astragali. Previous studies have shown that astragaloside IV plays an important role in the control of early- and mid-stage diabetes and late diabetic nephropathy. However, it is disappointing that the in vivo solubility of astragaloside IV and its bioavailability after oral administration are very low. We recently obtained a new water-soluble derivative of astragaloside IV-astragaloside formic acid (LS-102), which has higher bioavailability than the parent compound. In our previous study, we found that there was a significant inflammatory response in the perirenal adipose tissue of mice with obesity-related nephropathy induced by a high-fat diet (HFD), which was related to macrophage infiltration. We hypothesized that in model mice with obesity-related nephropathy, LS-102 effectively regulated the inflammatory response and pathological changes in obesity-related nephropathy through macrophages in perirenal adipose tissue. If this hypothesis is true, the effects of LS-102 and astragaloside IV on TGF-β1/Smad signal transduction will be further investigated.

Methods

In this study, adipose stem cells and an HFD-induced obesity-related nephropathy mouse model were used to observe the regulatory effect of LS-102 on perirenal fat inflammation and the mechanism. Adipose mesenchymal stem cells were extracted from mice that were fed a normal diet and those with obesity-related nephropathy. The effects of LS-102 on the proliferation of two kinds of cells were measured by the CCK-8 method. The levels of tumor necrosis factor-α (TNF-a) and plasminogen activator inhibitor-1 (PAI-1) were measured by ELISA. Obesity-related nephropathy mice were randomly divided into five groups: the HFD group, the LAS group (HFD+low concentration of astragaloside IV [10 mg/kg], intragastrically [ig]), the HAS group (HFD+high concentration of astragaloside IV [40 mg/kg], ig), the L102 group (HFD+low concentration of LS-102 [10 mg/kg], ig) and the H102 group (HFD+high concentration of LS-102 [40 mg/kg], ig). Body weight was measured, and the levels of serum glucose, high-density lipoprotein (HDL), low-density lipoprotein (LDL), triglyceride (TG), total cholesterol (TC), serum creatinine (Crea) and blood urea were measured. The kidneys were stained with HE, PAS and Masson's trichrome. Perirenal adipose tissue was harvested to examine the expression of CD68, LCA, CD11C, TNF-a, TGF-β1, Fn1, Smad2, Smad3, Smad4, and Smad7 by immunohistochemical staining, and F4/80 was examined by immunofluorescence staining.

Results

LS-102 significantly inhibited the in vitro secretion of TNF-a and PAI-1 by adipose stem cells in a concentration-dependent manner (P < 0.05). In vivo, the body weights in the LAS group, HAS group, L102 group and H102 group were significantly lower than those in the HFD group (P < 0.05). Except for that in the HFD group, the volume of perirenal adipocytes in the other groups was small and uniform (P < 0.05). Compared with the LAS, HAS, L102 and H102 groups, the HFD group had a larger glomerular cross-sectional area, proliferation of mesangial cells and the mesangial matrix, and increased matrix area/glomerular area (P < 0.05). The effect of LS-102 was better than that of astragaloside IV at the same concentration (P < 0.05). Compared with those in the HFD group, glucose, HDL-C, LDL-C and urea levels in the LAS group, HAS group, L102 group and H102 group were significantly decreased (P < 0.05). The expression of F4/80, CD68, LCA, TNF-a, CD11C, and PAI-1 in perirenal adipose tissue in the HFD group was significantly higher than that in the LAS group, HAS group, L102 group and H102 group (P < 0.05). Compared with those in the HFD group, the expression levels of TGF-β1 and Fn1 in the HAS group, L102 group and H102 group were significantly increased (P < 0.05). Compared with the HFD group, the HAS group, L102 group and H102 group had decreased immunopositive rates of Smad2, Smad3 and Smad4 (P < 0.05). At the same concentration, the effect of LS-102 was better than that of astragaloside IV (P < 0.05). There was no significant difference in the expression of Smad7 among the different experimental groups (P > 0.05).

Conclusion

Astragaloside IV and LS-102 improved the inflammatory reaction in perirenal adipose tissue and renal pathological changes in obesity-related nephropathy model mice and inhibited the TGF-β1/Smad signaling cascade. At the same concentration, the effect of LS-102 was better than that of astragaloside IV. These results suggest that LS-102 has a better protective effect against obesity-related nephropathy. LS-102 may be a new type of traditional Chinese medicine for the clinical treatment of obesity and its related metabolic diseases.

ATP-citrate lyase inhibitor improves ectopic lipid accumulation in the kidney in a db/db mouse model

AIM

We evaluated a novel treatment for obesity-related renal, an ATP-citrate lyase (ACL) inhibitor, to attenuate ectopic lipid accumulation (ELA) in the kidney and the ensuing inflammation.

MATERIALS AND METHODS

An ACL inhibitor was administered intragastrically to 12-week-old db/db mice for 30 days. The appearance of ELA was observed by staining kidney sections with Oil Red O, and the differences in tissue lipid metabolites were assessed by mass spectrometry. The anti-obesity and renoprotection effects of ACL inhibitors were observed by histological examination and multiple biochemical assays.

RESULTS

Using the AutoDock Vina application, we determined that among the four known ACL inhibitors (SB-204990, ETC-1002, NDI-091143, and BMS-303141), BMS-303141 had the highest affinity for ACL and reduced ACL expression in the kidneys of db/db mice. We reported that BMS-303141 administration could decrease the levels of serum lipid and renal lipogenic enzymes acetyl-CoA carboxylase (ACC), fatty acid synthase (FAS), HMG-CoA reductase (HMGCR), and diminish renal ELA in db/db mice. In addition, we found that reducing ELA improved renal injuries, inflammation, and tubulointerstitial fibrosis.

CONCLUSION

ACL inhibitor BMS-303141 protects against obesity-related renal injuries.

The inhibition of Nrf2 accelerates renal lipid deposition through suppressing the ACSL1 expression in obesity-related nephropathy

Background: Obesity has become a worldwide epidemic, and the incidence of obesity is increasing year by year. Obesity-related nephropathy (ORN) is a common kidney complication of obesity. Long-chain acyl-CoA synthetases-1, (ACSL1), is a key enzyme in the oxidative metabolism of fatty acids in mitochondria and ACSL1 may play a direct role in renal lipid deposition and promote the progress of ORN. In this study, we focus on the renoprotective role of ACSL1 in ORN.

Methods: Electron microscopy, immunohistochemical (IHC) staining, Western blot, and real-time PCR were used to detect the expression of ACSL1and Nrf2 in ORN patients, ob/ob mice and palmitic acid (PA)-treated HK-2 cells. Oil red staining and Elisa Kit were used to detect the intracellular FFA and TG contents in ob/ob mice and PA-treated HK-2 cells. Dihydroethidium (DHE) staining and the MDA/SOD measurement were used to detect the ROS production. In order to demonstrate the role of ACSL1 and the interaction between ACSL1 and Nrf2 in ORN, related siRNA and plasmid were transfected into HK-2 cells.

Results: More ROS production and renal lipid deposition have been found in ORN patients, ob/ob mice and PA-treated HK-2 cells. Compared with control, all the expression of ACSL1and Nrf2 were down-regulated in ORN patients, ob/ob mice and PA-treated HK-2 cells. The Nrf2 could regulate the expression of ACSL1 and the ACSL1 played the direct role in renal lipid deposition.

Conclusions: The Nrf2 is inhibited in ORN, resulting more ROS production and oxidative stress. Increased oxidative stress will suppress the expression of ACSL1, which could increase the intracellular FFA and TG contents, ultimately leading to renal lipid deposition in renal tubulars and accelerating the development of ORN.

Hemodynamics as Measured With Color Doppler Sonography in Early-Stage Obesity-Related Nephropathy in Children

OBJECTIVES

We retrospectively studied hemodynamic changes in the interlobar artery to assess the clinical value of color Doppler sonography for detecting preclinical obesity-related nephropathy.

METHODS

Color Doppler renal sonography was performed in 52 children with obesity-related nephropathy and 51 control children with simple obesity. The interlobar artery resistive index (RI) was measured and compared with clinical data and laboratory indicators.

RESULTS

The left RI (mean ± SD, 0.65 ± 0.05 versus 0.60 ± 0.08; t = 3.85), right RI (0.64 ± 0.03 versus 0.59 ± 0.02; t = 10.00), and mean RI (0.64 ± 0.05 versus 0.59 ± 0.06; t = 5.00) revealed large statistically significant increases in the obesity-related nephropathy group (all P < .01). In the obesity-related nephropathy group, a positive correlation was found between the mean RI and 24-hour urine trace albumin (r = 0.47; P < .01), triglycerides (r = 0.98; P < .01), and body mass index (r = 0.28; P < .05). The 24-hour urine trace albumin and triglycerides were higher in the obesity-related nephropathy group than the control group (P < .05). In the control group, a mild positive correlation was also found between the mean RI and body mass index (r = 0.24; P < .05).

CONCLUSIONS

Color Doppler sonography successfully indicated renal hemodynamic changes and has diagnostic value for early-stage obesity-related nephropathy.