Piperazine ferulate prevents high-glucose-induced filtration barrier injury of glomerular endothelial cells

Filtration barrier injury induced by high glucose (HG) levels leads to the development of diabetic nephropathy. The endothelial glycocalyx plays a critical role in glomerular barrier function. In the present study, the effects of piperazine ferulate (PF) on HG-induced filtration barrier injury of glomerular endothelial cells (GEnCs) were investigated and the underlying mechanism was assessed. Immunofluorescence was used to observe the distribution of the glycocalyx as well as the expression levels of syndecan-1 and Zonula occludens-1 (ZO-1). Endothelial permeability assays were performed to assess the effects of PF on the integrity of the filtration barrier. Protein and mRNA expression levels were measured by western blotting and reverse transcription-quantitative PCR analyses, respectively. In vitro experiments revealed that adenosine monophosphate-activated protein kinase (AMPK) mediated HG-induced glycocalyx degradation and endothelial barrier injury. PF inhibited the HG-induced endothelial barrier injury and restored the expression levels of heparanase-1 (Hpa-1), ZO-1 and occludin-1 by AMPK. In vivo assays demonstrated that PF reduced the expression levels of Hpa-1, increased the expression levels of ZO-1 and attenuated glycocalyx degradation in the glomerulus. These data suggested that PF attenuated HG-induced filtration barrier injury of GEnC by regulating AMPK expression.

Piperazine ferulate attenuates high glucose‑induced mesangial cell injury via the regulation of p66Shc

Diabetic nephropathy (DN) is a severe microvascular complication of diabetes. Hyperglycemia-induced glomerular mesangial cells injury is associated with microvascular damage, which is an important step in the development of DN. Piperazine ferulate (PF) has been reported to exert protective effects against the progression of DN. However, whether PF prevents high glucose (HG)-induced mesangial cell injury remains unknown. The aim of the present study was to investigate the effects of PF on HG-induced mesangial cell injury and to elucidate the underlying mechanisms. Protein and mRNA expression levels were determined via western blot analysis and reverse transcription-quantitative PCR, respectively. IL-6 and TNF-α levels were measured using ELISA. Reactive oxygen species levels and NF-κB p65 nuclear translation were determined via immunofluorescence analysis. Apoptosis was assessed by measuring lactate dehydrogenase (LDH) release, as well as using MTT and flow cytometric assays. The mitochondrial membrane potential of mesangial cells was determined using the JC-1 kit. The results revealed that LDH release were increased; however, cell viability and mitochondrial membrane potential were decreased in the HG group compared with the control group. These changes were inhibited after the mesangial cells were treated with PF. Moreover, PF significantly inhibited the HG-induced production of inflammatory cytokines and the activation of NF-κB in mesangial cells. PF also attenuated the HG-induced upregulation of the expression levels of fibronectin and collagen 4A1. Furthermore, the overexpression of p66^{Src homology/collagen (Shc)} abolished the protective effect of PF on HG-induced mesangial cell injury. In vivo experiments revealed that PF inhibited the activation of inflammatory signaling pathways, glomerular cell apoptosis and mesangial matrix expansion in diabetic mice. Collectively, the present findings demonstrated that PF attenuated HG-induced mesangial cells injury by inhibiting p66^Shc.

Therapeutic Efficacy of Piperazine Ferulate Combined With Irbesartan in Diabetic Nephropathy: A Systematic Review and Meta-analysis

PURPOSE

Irbesartan is widely used clinically in the treatment of diabetic nephropathy (DN). It is believed that piperazine ferulate (PF) combined with irbesartan could result in an improved efficacy in the treatment of DN. We present the latest meta-analysis that details the combination of PF and irbesartan therapy.

METHODS

Before January 31, 2020, we searched various electronic databases for appropriate articles. Our search was not restricted by keyword or language. We then filtered all articles using certain criteria and assessed the quality of the qualified studies.

FINDINGS

The meta-analysis included 12 trials that involved 1300 patients (650 in the experimental group and 650 in the control group). The ages of the patients ranged from 30 to 79 years. Compared with irbesartan alone, the total effective rate of PF combined with irbesartan was significantly higher (odds ratio [OR] = 4.95; 95% CI, 3.11-7.58; P < 0.0001). The blood glucose level was controlled by significantly decreasing the fasting plasma glucose level (mean difference [MD] = -1.40; 95% CI, -2.70 to -0.11; P = 0.03) and 2-h plasma glucose level (MD = -1.65; 95% CI, -2.49 to -0.82; P < 0.0001). The combination therapy significantly decreased the levels of serum creatinine (MD = -10.24; 95% CI, -15.25 to -5.23; P < 0.0001), 24-h urinary protein (MD = -0.07; 95% CI, -0.09 to -0.05; P < 0.0001), urinary albumin excretion rate (MD = -22.52; 95% CI, -30.20 to -14.84; P < 0.0001), urinary β₂-microglobulin (MD = -0.15; 95% CI, -0.17 to -0.13; P < 0.0001), and blood urea nitrogen (MD = -1.54; 95% CI, -2.36 to -0.72; P = 0.0002), which was beneficial for improving and protecting renal function. The renal microcirculation was improved by significantly decreasing the whole blood viscosity low shear (MD = -1.41; 95% CI, -1.84 to -0.99; P < 0.0001), whole blood viscosity high shear (MD = -0.54; 95% CI, -0.63 to -0.45; P < 0.0001), whole blood viscosity (MD = -1.31; 95% CI, -1.79 to -0.83; P < 0.0001), whole blood reduction viscosity (MD = -1.42; 95% CI, -1.79 to -1.06; P < 0.0001), platelet aggregation rate (MD = -0.42; 95% CI, -0.50 to -0.35; P < 0.0001), plasma viscosity (MD = -13.02; 95% CI, -15.47 to -10.56; P < 0.0001), and fibrinogen content (MD = -0.25; 95% CI, -0.42 to -0.09; P = 0.003).

IMPLICATIONS

PF combined with irbesartan could improve the efficiency in the treatment of DN. However, these results should be handled carefully. These findings should be verified by several rigorous randomized controlled trials.

Distinct Responses of Gut Microbiota to Jian-Pi-Yi-Shen Decoction Are Associated With Improved Clinical Outcomes in 5/6 Nephrectomized Rats

Gut dysbiosis contributes to the development and progression of chronic kidney disease (CKD) and its complications. However, the effect of drugs on the gut microbiota of CKD patients and its influence on treatment outcomes remains to be explored. Here, we assessed whether the response of gut microbiota to the traditional Chinese medicine Jian-Pi-Yi-Shen (JPYS) decoction differed from that to piperazine ferulate (PF), a kidney-targeted drug, by 16S rDNA sequencing, and whether the difference could be linked with drug-specific clinical outcomes. We showed that both JPYS and PF improved renal function, but only JPYS was able to restore the blood reticulocyte counting and serum calcium level in CKD rats. We also found that weighted UniFrac beta-diversity of the gut microbiome of the JPYS treated rats was significantly different from that of PF. Microbiome markers of drug-specific response were identified and subjected to correlation network analysis, together with clinical parameters and KEGG pathways. Among the microbiome markers of CKD, Corynebacterium was found to form a network hub that was closely correlated with the JPYS responder Enterococcus, suggesting a potential indirect impact of JPYS on Corynebacterium via interspecies interactions. We also identified two network hubs of the PF responder Blautia and the JPYS-only marker Coprococcus, which were connected with many genera and clinical parameters. They might serve as keystone taxa driving the response of gut microbiota to the drugs and influence host outcomes. Moreover, the JPYS-only marker Clostridium_XIVb was found to be connected to many pathways that are associated with CKD progression and might account for the improved outcomes in the JPYS treated rats. At last, the identified keystone markers of drug response were validated by qPCR for their differential abundance between CKD and the two drugs. Taken together, our study revealed that the responses of gut microbiota to JPYS were distinct from that to PF, and pinpointed drug-specific keystone microbiome markers closely correlated to clinical parameters, which could serve as candidate microbiome targets for further studies on their roles in medicating the drug efficacy of TCM in CKD.