Left ventricular hypertrophy (LVH) is a common complication in patients with CKD and an independent risk factor for death. Changes in the levels of uremic solutes or Klotho have been reported to be related to CKD, whereas the relationships between these factors and CKD-associated LVH remain unclear. Here, we investigated the interaction between Klotho and indoxyl sulfate (IS), a typical uremic solute, in CKD-associated LVH. In a survey of 86 patients with CKD, a negative relationship was found between serum levels of IS and Klotho (r=−0.59, P<0.001). Furthermore, serum levels of IS and Klotho were independently associated with LVH (for IS: r=0.69, P<0.001; for Klotho: r=−0.49, P<0.001). In normal mice, intraperitoneal injection of IS for 8 weeks induced LVH accompanied by substantial downregulation of renal Klotho. Notably, IS-induced LVH was more severe in heterozygous Klotho-deficient (kl/+) mice. In vitro, treatment with Klotho strongly inhibited IS-induced cardiomyocyte hypertrophy by blocking oxidative stress and inhibiting p38 and extracellular signal–regulated protein kinase 1/2 signaling pathways. In a mouse model of CKD-associated LVH, the renal expression of Klotho was lower and the level of serum IS was higher than in healthy controls. Moreover, treatment of CKD mice with Klotho protein significantly restrained the development of LVH. Taken together, these results suggest that Klotho is an endogenous protector against IS-induced LVH, and the imbalance between Klotho and IS may contribute to the development of LVH in CKD.

Renal fibrosis is the main pathological characteristic of chronic kidney disease (CKD), whereas the underlying mechanisms of renal fibrosis are not clear yet. Herein, we found an increased expression of microRNA-34a (miR-34a) in renal tubular epithelial cells of patients with renal fibrosis and mice undergoing unilateral ureteral obstruction (UUO). In miR-34a-/- mice, miR-34a deficiency attenuated the progression of renal fibrosis following UUO surgery. The miR-34a overexpression promoted epithelial-to-mesenchymal transition (EMT) in cultured human renal tubular epithelial HK-2 cells, which was accompanied by sharp downregulation of Klotho, an endogenous inhibitor of renal fibrosis. Luciferase reporter assay revealed that miR-34a downregulated Klotho expression though direct binding with the 3' UTR of Klotho. Conversely, overexpression of Klotho prevented miR-34a-induced EMT in HK-2 cells. Furthermore, results showed that miR-34a was induced by transforming growth factor β1 (TGF-β1) through p53 activation, whereas dihydromyricetin could inhibit TGF-β1-induced miR-34a overexpression. Accordingly, dihydromyricetin administration dramatically restored the aberrant upregulation of miR-34a and Klotho reduction in obstructed kidney, and markedly ameliorated renal fibrosis in the Adriamycin nephropathy and UUO model mice. These findings suggested that miR-34a plays an important role in the progression of renal fibrosis, which provides new insights into the pathogenesis and treatment of CKD.

Rationale: The dysfunctional gut-kidney axis forms a vicious circle, which eventually becomes a catalyst for the progression of chronic kidney disease (CKD) and occurrence of related complications. However, the pathogenic factors of CKD-associated intestinal dysfunction and its mechanism remain elusive.

Intermolecular interaction was determined by biolayer interferometry. Molecular dynamic simulation was performed on a ZDOCK server at Peng Cheng Laboratory. SARS-CoV-2 S1 binding and S pseudovirions entry to targeted cells were investigated by immunofluorescence microscopy, Western blot, and luciferase assay. The significant differences (P) were calculated by SPSS 25.0 (IBM Corp, Armonk, NY). More details are shown in the Supplementary Methods.

Background/Aims: Geriatric nutritional risk index (GNRI) was developed as a “nutrition-related” risk index and was reported in different populations as associated with the risk of all-cause and cardiovascular morbidity and mortality. Therefore, GNRI can be used to classify patients according to a risk of complications in relation to conditions associated with protein-energy wasting (PEW). However, not all reports pointed to the prognostic ability of the GNRI. The purpose of this study was to assess the associations of GNRI with mortality in chronic hemodialysis patients. Methods: We electronically searched original articles published in peer-reviewed journals from their inception to September 2018 in The PubMed, Embase, and the Cochrane Library databases. The primary outcome was all-cause and cardiovascular mortality. We pooled unadjusted and adjusted odds ratios (ORs) with 95% confidence intervals (95% CIs) using Review Manager 5.3 software. Results: A total of 10,739 patients from 19 cohort studies published from 2010 to 2018 were included. A significant negative association was found between the GNRI and all-cause mortality in patients with chronic hemodialysis (OR, 0.90; 95% CI, 0.84-0.97, p=0.004) (per unit increase) and (OR, 2.15; 95% CI, 1.88-2.46, p＜0.00001) (low vs. high GNRI). Moreover, there was also a significant negative association between the GNRI (per unit increase) and cardiovascular events (OR, 0.98; 95% CI, 0.97-1.00, p=0.01), as well as cardiovascular mortality (OR, 0.89; 95% CI, 0.80-0.99, p=0.03). Conclusion: Our findings supported the hypothesis that the low GNRI is associated with an increased risk of all-cause and cardiovascular mortality in chronic hemodialysis patients. Based on our literature review, GNRI has been found to be an effective tool for identifying patients with nutrition-related risk of all-cause and cardiovascular disease.