OBJECTIVES: To clarify the causal relationship between the level of cytoplasmic unactivated mineralocorticoid receptor (MR) and the development of tubulointerstitial nephritis (TIN), and to evaluate the impact of MR on dyslipidemia, particularly secondary hyperlipemia, in patients with diabetic kidney disease. METHODS: We conducted a two-sample Mendelian randomization study using genome-wide association study (GWAS) summary data. Genetic variants associated with MR levels were selected as exposures, with TIN and lipid profiles [including low-density lipoprotein cholesterol (LDL-C), triglyceride, and high-density lipoprotein cholesterol] as outcomes. A two-step Mendelian randomization approach was used to assess TIN as a mediator, employing inverse variance weighted regression as the primary analysis, supplemented by Mendelian randomization-Egger, weighted median, and sensitivity analyses. RESULTS: Cytoplasmic unactivated MR level exhibited a significant causal association with a decreased risk of TIN (OR = 0.8598, 95% CI [0.7775-0.9508], P < 0.001). Although no significant causal relationship was identified between MR level and secondary hyperlipemia, a potential association of cytoplasmic unactivated MR level with lower LDL-C levels was observed (OR = 0.9901, 95% CI [0.9821-0.9983], P = 0.018). Additionally, TIN exhibited causal links with secondary hyperlipemia (OR = 1.0016, 95% CI [1.0002-1.0029], P = 0.020) and elevated LDL-C (OR = 1.0111, 95% CI [1.0024-1.0199], P = 0.012), particularly LDL-C in European males (OR = 1.0230, 95% CI [1.0103-1.0358], P < 0.001). Inverse Mendelian randomization analysis revealed causal relationships between TIN and genetically predicted triglyceride (OR = 0.7027, 95% CI [0.6189-0.7978], P < 0.001), high-density lipoprotein cholesterol (OR = 1.1247, 95% CI [1.0019-1.2626], P = 0.046), and LDL-C (OR = 0.8423, 95% CI [0.7220-0.9827], P = 0.029). Notably, TIN mediated 16.7% of the causal association between MR and LDL-C levels. CONCLUSIONS MR plays a critical role in the development of TIN and lipid metabolism, highlighting the potential of MR-antagonists in reducing renal damage and lipid metabolism-associated complications.
Humans ; Mendelian Randomization Analysis ; Nephritis, Interstitial/metabolism* ; Receptors, Mineralocorticoid/genetics* ; Lipid Metabolism/genetics* ; Genome-Wide Association Study ; Male ; Female ; Polymorphism, Single Nucleotide ; Dyslipidemias/metabolism*

Autosomal dominant tubulointerstitial kidney disease (ADTKD) is a rare autosomal dominant hereditary disorder characterized by hyperuricemia, gout, impaired urinary concentration, and progressive renal failure. It is primarily caused by mutations in uromodulin (UMOD) gene. This study reports a family with ADTKD in which whole-exome sequencing and Sanger sequencing identified a missense mutation in the UMOD gene, c.761A>C (p.H254P), present in both the proband and affected relatives. According to American College of Medical Genetics and Genomics (ACMG) guidelines, this variant is classified as likely pathogenic. The mutation results in an amino acid substitution that may impair UMOD protein folding and intracellular trafficking. UMOD gene mutations are associated with ADTKD, and genetic testing plays a vital role in the early diagnosis and treatment of this condition, highlighting its importance in the diagnosis of rare kidney diseases.
Adult ; Humans ; Male ; Exome Sequencing ; Mutation ; Mutation, Missense ; Nephritis, Interstitial/genetics* ; Pedigree ; Uromodulin/genetics*

BACKGROUND/AIMS: There has been controversy about the role of Toll-like receptor 2 (TLR2) in renal injury following ureteric obstruction. Although inhibition of the renin angiotensin system (RAS) reduces TLR2 expression in mice, the exact relationship between TLR2 and RAS is not known. The aim of this study was to determine whether the RAS modulates TLR2. METHODS: We used 8-week-old male wild type (WT) and TLR2-knockout (KO) mice on a C57Bl/6 background. Unilateral ureteral obstruction (UUO) was induced by complete ligation of the left ureter. Angiotensin (Ang) II (1,000 ng/kg/min) and the direct renin inhibitor aliskiren (25 mg/kg/day) were administrated to mice using an osmotic minipump. Molecular and histologic evaluations were performed. RESULTS: Ang II infusion increased mRNA expression of TLR2 in WT mouse kidneys (p < 0.05). The expression of renin mRNA in TLR2-KO UUO kidneys was significantly higher than that in WT UUO kidneys (p < 0.05). There were no differences in tissue injury score or mRNA expression of monocyte chemotactic protein 1 (MCP-1), osteopontin (OPN), or transforming growth factor beta (TGF-beta) between TLR2-KO UUO and WT UUO kidneys. However, aliskiren decreased the tissue injury score and mRNA expression of TLR2, MCP-1, OPN, and TGF-beta in WT UUO kidneys (p < 0.05). Aliskiren-treated TLR2-KO UUO kidneys showed less kidney injury than aliskiren-treated WT UUO kidneys. CONCLUSIONS: TLR2 deletion induced activation of the RAS in UUO kidneys. Moreover, inhibition of both RAS and TLR2 had an additive ameliorative effect on UUO injury of the kidney.
Amides/*pharmacology ; Angiotensin II/pharmacology ; Animals ; Disease Models, Animal ; Fibrosis ; Fumarates/*pharmacology ; Kidney/*drug effects/metabolism/pathology ; Male ; Mice, Inbred C57BL ; Mice, Knockout ; Nephritis, Interstitial/genetics/metabolism/pathology/*prevention & control ; RNA, Messenger/genetics/metabolism ; Renin/*antagonists & inhibitors/metabolism ; Renin-Angiotensin System/*drug effects ; Toll-Like Receptor 2/deficiency/drug effects/genetics/*metabolism ; Ureteral Obstruction/*drug therapy/genetics/metabolism/pathology

Total saponins of Panax notoginseng (PNS) have been shown to ameliorate renal interstitial fibrosis. Ginsenoside Rg1, a panaxatriol saponin, is one of the major active molecules from PNS. The present study was undertaken to investigate the effect of ginsenoside Rg1 on renal fibrosis in rats with unilateral ureteral obstruction (UUO). The rats were randomly divided into 3 groups: sham-operation (n=15), UUO (n=15) and UUO with ginsenoside Rg1 treatment (n=15, 50 mg per kg body weight, intraperitoneally (i.p.) injected). The rats were sacrificed on Days 7 and 14 after the surgery. Histological examination demonstrated that ginsenoside Rg1 significantly inhibited interstitial fibrosis including tubular injury as well as collagen deposition. alpha-smooth muscle actin (alpha-SMA) and E-cadherin are two markers of tubular epithelial-myofibroblast transition (TEMT). Interestingly, ginsenoside Rg1 notably decreased alpha-SMA expression and simultaneously enhanced E-cadherin expression. The messenger RNA (mRNA) of transforming growth factor-beta1 (TGF-beta1), a key mediator to regulate TEMT, in the obstructed kidney increased dramatically, but was found to decrease significantly after administration of ginsenoside Rg1. Further study showed that ginsenoside Rg1 considerably decreased the levels of both active TGF-beta1 and phosphorylated Smad2 (pSmad2). Moreover, ginsenoside Rg1 substantially suppressed the expression of thrombospondin-1 (TSP-1), a cytokine which can promote the transcription of TGF-beta1 mRNA and the activation of latent TGF-beta1. These results suggest that ginsenoside Rg1 inhibits renal interstitial fibrosis in rats with UUO. The mechanism might be partly related to the blocking of TEMT via suppressing the expression of TSP-1.
Actins ; biosynthesis ; Animals ; Cadherins ; biosynthesis ; Collagen Type I ; genetics ; metabolism ; Fibronectins ; genetics ; metabolism ; Ginsenosides ; pharmacology ; Immunohistochemistry ; Male ; Nephritis, Interstitial ; drug therapy ; genetics ; metabolism ; pathology ; Panax notoginseng ; chemistry ; RNA, Messenger ; biosynthesis ; genetics ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Reverse Transcriptase Polymerase Chain Reaction ; Smad2 Protein ; biosynthesis ; Thrombospondin 1 ; biosynthesis ; genetics ; Transforming Growth Factor beta1 ; biosynthesis ; genetics ; Ureteral Obstruction ; metabolism ; pathology

OBJECTIVE: To investigate the effect of enalapril on renal interstitial fibrosis in rats with unilateral ureteral obstruction(UUO). METHODS: UUO model was induced by ligating the left ureter in rats. Male Sprague-Dawley(SD) rats were randomly divided into a sham-operated group(n=16), a UUO model group(n=24), and an enalapril treated group(n=24). The rats were treated with 10 mg/kg.d by gastric gavage in the enalapril treated group from 24 h before the operation, and the rats were treated with the identical dose of normal saline in the other 2 groups. The rats were sacrificed at 3,7,14, and 21 days after UUO. Pathological changes of the renal tissue were observed by HE and Masson staining, the mRNA expression of collagen I (Col I) was detected by real-time PCR, and the protein expression of connective tissue growth factor (CTGF) was detected by Western blot. RESULTS: The renal interstitial damage index, relative collagen area and the expression of Col I mRNA and CTGF in the renal tissues in the model group increased with the prolongation of obstruction. Enalapril significantly reduced the renal interstitial damage index and relative collagen area, and inhibted the expression of Col I mRNA and CTGF. There was significant difference on day 3,7,and 14 (P<0.05), but not on day 21 (P>0.05). CONCLUSION Enalapril significantly attenuates renal interstitial fibrosis by supressing the expression of Col I mRNA and CTGF.
Animals ; Collagen Type I ; biosynthesis ; genetics ; Connective Tissue Growth Factor ; biosynthesis ; genetics ; Enalapril ; therapeutic use ; Male ; Nephritis, Interstitial ; etiology ; prevention & control ; Nephrosclerosis ; etiology ; prevention & control ; RNA, Messenger ; biosynthesis ; genetics ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Ureteral Obstruction ; complications

OBJECTIVETo study the effect of Kurarinone on renal tubular epithelial cell-mesenchyma (ECM) trans-differentiation in rats with renal interstitial fibrosis and to explore its possible mechanisms.

METHODSThe rat model of renal interstitial fibrosis was established by unilateral ureteral obstruction (UUO). Sprague-Dawley male rats were randomly divided into 3 groups, the sham-operated group, the UUO group and the Kurarinone treated group (KTG). Rats in the KTG were intraperitoneally injected with Kurarinone 100 mg/kg daily after modeling. Five rats of each group were killed respectively at day 7, 14 and 21 after UUO. The serum levels of blood urea nitrogen (BUN), serum creatinine (SCr), total protein (TP) and albumin (ALB), 24-h urinary protein excretion in rats were measured. Pathological changes of renal tissue were observed by PAS and Masson stain. The expression of transforming growth factor beta1 (TGF-beta1), Smad3, alpha-smooth muscle actin (alpha-SMA) and collagen I (Col I) in kidney were determined with immunohistochemistry. And the expressions of TGF-beta1 and alpha-SMA mRNA in renal tissue were determined using reverse transcription polymerase chain reaction (RT-PCR).

RESULTSThe expression of TGF-beta1, Smad3, alpha-SMA and Col I in the KTG was significantly decreased as compared with that in the UUO group respectively, and the degree of tubular damage and renal interstitial fibrosis was also ameliorated more obviously in the KTG. The TGF-beta1 and alpha-SMA mRNA expressions in KTG were significantly lower than those in the UUO group determined at the corresponding time points (P < 0.05).

CONCLUSIONKurarinone could down-regulate the expression of TGF-beta1 and Col I, inhibit EC-M trans-differentiation, suppress the activation and proliferation of myofibroblast. The probable pathway may be by way of down-regulating Smad3 expression to interfere its induction on intercellular signal transduction and consequently ameliorate renal interstitial fibrosis.

Animals ; Cell Transdifferentiation ; drug effects ; Collagen Type I ; biosynthesis ; genetics ; Epithelial Cells ; drug effects ; metabolism ; pathology ; Fibrosis ; Flavonoids ; pharmacology ; Immunohistochemistry ; Kidney ; drug effects ; metabolism ; pathology ; Kidney Tubules ; drug effects ; metabolism ; pathology ; Male ; Mesoderm ; drug effects ; metabolism ; pathology ; Nephritis, Interstitial ; physiopathology ; RNA, Messenger ; biosynthesis ; genetics ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Reverse Transcriptase Polymerase Chain Reaction ; Transforming Growth Factor beta1 ; biosynthesis ; genetics

OBJECTIVETo study the effect and mechanism of Kangxianling (KXL, a TCM herbal compound) on renal interstitial fibrosis induced by unilateral ureteral obstruction (UUO).

METHODSEighteen male SD rats were randomly divided into 3 groups, 6 in each group, the sham operated group, the model group, and the KXL group. Renal interstitial fibrosis model was established in rats by UUO. After rats were raised for additional 14 days, their body weight, serum levels of creatinine (SCr) and blood urea nitrogen (BUN) were analyzed. Then rats were sacrificed, their renal pathology examined by HE staining and PASM staining; expressions of transforming growth factor-beta1 (TGF-beta1), hepatocyte growth factor (HGF) mRNA, and a-smooth muscle actin (alpha-SMA), TGF-beta1 receptor I (TbetaR I), TGF-beta1 receptor II (TbetaR II) and hepatocyte growth factor receptor (C-Met) protein in kidney tissue were determined by RT-PCR and Western blotting respectively.

RESULTSSCr and BUN in the model group were significantly higher than those in the sham operated group (P <0.05). Expressions of TGF-beta1 mRNA and a-SMA, TbetaR I , TbetaR II and C-Met protein in kidney tissue in the model group significantly up-regulated and mRNA expression of HGF significantly down-regulated, and obvious hyperplasia of the base member of glomeruli was seen. After intervention with KXL, BUN content significantly lowered, alpha-SMA, TbetaR I and TbetaR II protein expression decreased and HGF mRNA expression up-regulated significantly in the treated group, with slight pathological changes only shown as mild hyperplasia of the base member of glomeruli and renal tubules.

CONCLUSIONKXL could inhibit the protein expressions of a-SMA, TbetaR I , TbetaR II and increase the mRNA expression of HGF, which is a protective factor against renal fibrosis. Therefore, it is effective in alleviating the renal interstitial fibrosis and improving the renal function in UUO rats.

Animals ; Blotting, Western ; Drugs, Chinese Herbal ; therapeutic use ; Fibrosis ; prevention & control ; Hepatocyte Growth Factor ; biosynthesis ; genetics ; Kidney ; drug effects ; metabolism ; pathology ; Male ; Nephritis, Interstitial ; etiology ; pathology ; prevention & control ; Nephrosclerosis ; pathology ; prevention & control ; Phytotherapy ; RNA, Messenger ; biosynthesis ; genetics ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Reverse Transcriptase Polymerase Chain Reaction ; Ureteral Obstruction ; complications