Epalrestat Research Articles

Protective effect of alpha-lipoic acid and epalrestat on oxaliplatin-induced peripheral neuropathy in zebrafish.

Oxaliplatin is a platinum-based anti-cancer drug widely used in colorectal cancer patients, but it may cause peripheral neuropathy. As one of the main causes of oxaliplatin-induced peripheral neuropathy (OPN) is oxidative stress, which is also a key factor causing diabetic peripheral neuropathy (DPN), the aim of this study was to evaluate the preventive effects of alpha-lipoic acid (ALA) and epalrestat (EP), which are used for the treatment of DPN, in an OPN zebrafish model. Tg(nbt:dsred) transgenic zebrafish, with sensory nerves in the peripheral lateral line, were treated with oxaliplatin, oxaliplatin/EP, and oxaliplatin/ALA for 4 days. A confocal microscope was used to visualize and quantify the number of axon bifurcations in the distal nerve ending. To analyze the formation of synapses on sensory nerve terminals, quantification of membrane-associated guanylate kinase (MAGUK) puncta was performed using immunohistochemistry. The number of axon bifurcations and intensity of MAGUK puncta were significantly reduced in the oxaliplatin-treated group compared with those in the embryo medium-treated group. In both the oxaliplatin/EP and oxaliplatin/ALA-treated groups, the number of axon bifurcations and intensity of MAGUK puncta were greater than those in the oxaliplatin-treated group (p < .0001), and no significant difference was observed between larvae treated with oxaliplatin/ALA 1 μM and oxaliplatin/EP 1 μM (p = .4292). ALA and EP have protective effects against OPN in zebrafish. Our findings show that ALA and EP can facilitate more beneficial treatment for OPN.

A dual-acting aldose reductase inhibitor impedes oxidative and carbonyl stress in tissues of fructose- and streptozotocin-induced rats: comparison with antioxidant stobadine

Inhibiting aldose reductase (ALR2, AR) as well as maintaining a concomitant antioxidant (AO) activity via dual-acting agents may be a rational approach to prevent cellular glucotoxicity and at least delay the progression of diabetes mellitus (DM). This study was aimed at evaluating the dual-acting AR inhibitor (ARI) cemtirestat (CMTI) on tissue oxidative stress (OS) and carbonyl stress (CS) biomarkers in rats exposed to fructose alone (F) or fructose plus streptozotocin (D; type-2 diabetic). D and F rats were either untreated or treated daily with low- or high-dose CMTI, ARI drug epalrestat (EPA) or antioxidant stobadine (STB) for 14 weeks. Malondialdehyde (MDA), glutathione S-transferase (GST), nitric oxide synthase (NOS), and catalase (CAT) were increased in the sciatic nerve of F and D. These increases were attenuated by low doses of CMTI and STB in D, but exacerbated by low-dose EPA and high-dose CMTI in F. STB and CMTI and to a lesser extent EPA improved MDA, protein-carbonyl, GST and CAT in the hearts and lungs of F and D. CMTI and STB were more effective than EPA in improving the increased MDA and protein-carbonyl levels in the kidneys of F and especially D. CMTI ameliorated renal GST inhibition in D. In the lungs, hearts, and kidneys of F and D, the GSH to GSSG ratio decreased and caspase-3 activity increased, but partially resolved with treatments. In conclusion, CMTI with ARI/AO activity may be advantageous in overcoming OS, CS, and their undesirable consequences, with low dose efficacy and limited toxicity, compared to ARI or antioxidant alone.

AKR1B1 inhibition using NARI-29-an Epalrestat analogue-alleviates Doxorubicin-induced cardiotoxicity via modulating Calcium/CaMKII/MuRF-1 axis

The clinical use of doxorubicin (Dox) is narrowed due to its carbonyl reduction to doxorubicinol (Doxol) implicating resistance and cardiotoxicity. Hence, in the present study we have evaluated the cardioprotective effect of AKR1B1 (or aldose reductase, AR) inhibitor NARI-29 (epalrestat (EPS) analogue) and its effect in the Dox-modulated calcium/CaMKII/MuRF1 axis. Initially, the breast cancer patient survival associated with AKR1B1 expression was calculated using Kaplan Meier-plotter (KM-plotter). Further, breast cancer, cardiomyoblast (H9c2), and macrophage (RAW 264.7) cell lines were used to establish the in vitro combination effect of NARI-29 and Dox. To develop the cardiotoxicity model, mice were given Dox 2.5 mg/kg (i.p.), biweekly. The effect of AKR1B1 inhibition using NARI-29 on molecular and cardiac functional changes was measured using echocardiography, fluorescence-imaging, ELISA, immunoblotting, flowcytometry, High-Performance Liquid Chromatography with Fluorescence Detection (HPLC-FD) and cytokine-bead array methods. The bioinformatics data suggested that a high expression of AKR1B1 is associated with significantly low survival of breast cancer patients undergoing chemotherapy; hence, it could be a target for chemo-sensitization and chemo-prevention. Further, in vitro studies showed that AKR1B1 inhibition with NARI-29 has increased the accumulation and sensitized Dox to breast cancer cell lines. However, treatment with NARI-29 has alleviated the Dox-induced toxicity to cardiomyocytes and decreased the secretion of inflammatory cytokines from RAW 264.7 cells. In vivo studies revealed that the NARI-29 (25 and 50 mg/kg) has prevented the functional, histological, biochemical, and molecular alterations induced by Dox treatment. Moreover, we have shown that NARI-29 has prevented the carbonyl reduction of Dox to Doxol in the mouse heart, which reduced the calcium overload, prevented phosphorylation of CaMKII, and reduced the expression of MuRF1 to protect from cardiac injury and apoptosis. Hence in conclusion, AKR1B1 inhibitor NARI-29 could be used as an adjuvant therapeutic agent with Dox to prevent cardiotoxicity and synergize anti-breast cancer activity.

Epalrestat Enhances MTS Reduction Activity Independent of Cell Numbers in Bovine Aortic Endothelial Cells

The 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay is used as a major method to evaluate cell viability. However, in some cases, the results may reflect mitochondrial status regardless of viability. Epalrestat (EPS) is currently available for the treatment of diabetic neuropathy. In this study, we report that EPS at near-plasma concentrations increases MTS reduction activity independent of cell number in bovine aortic endothelial cells. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a key transcription factor that plays a pivotal role in inducing the expression of genes encoding detoxifying and defensive proteins. Sulforaphane (an Nrf2 activator) also increased MTS-reducing activity, similar to EPS. Knockdown of Nrf2 by short interfering RNA suppressed EPS-induced MTS reduction. These results suggest that EPS increases MTS reduction activity via the Nrf2 pathway. Furthermore, the results that EPS increases ATP production and that electron transfer chain inhibitors suppress EPS-induced MTS reduction activity suggest that EPS may activate mitochondrial status. Because mitochondrial disorders cause numerous diseases, we suggest that EPS has new beneficial properties that may prevent the development and progression of disorders caused by mitochondrial dysfunction.

Trans-(±)-Kusunokinin Binding to AKR1B1 Inhibits Oxidative Stress and Proteins Involved in Migration in Aggressive Breast Cancer.

Synthetic trans-(±)-kusunokinin ((±)KU), a potential anticancer substance, was revealed to have an inhibitory effect on breast cancer. According to the computational modeling prediction, AKR1B1, an oxidative stress and cancer migration protein, could be a target protein of trans-(-)-kusunokinin. In this study, we determined the binding of (±)KU and AKR1B1 on triple-negative breast and non-serous ovarian cancers. We found that (±)KU exhibited a cytotoxic effect that was significantly stronger than zopolrestat (ZP) and epalrestat (EP) (known AKR1B1 inhibitors) on breast and ovarian cancer cells. (±)KU inhibited aldose reductase activity that was stronger than trans-(-)-arctiin ((-)AR) but weaker than ZP and EP. Interestingly, (±)KU stabilized AKR1B1 on SKOV3 and Hs578T cells after being heated at 60 and 75 °C, respectively. (±)KU decreased malondialdehyde (MDA), an oxidative stress marker, on Hs578T cells in a dose-dependent manner and the suppression was stronger than EP. Furthermore, (±)KU downregulated AKR1B1 and its downstream proteins, including PKC-δ, NF-κB, AKT, Nrf2, COX2, Twist2 and N-cadherin and up-regulated E-cadherin. (±)KU showed an inhibitory effect on AKR1B1 and its downstream proteins, similar to siRNA-AKR1B1. Interestingly, the combination of siRNA-AKR1B1 with EP or (±)KU showed a greater effect on the suppression of AKR1B1, N-cadherin, E-cadherin and NF-κB than single treatments. Taken together, we concluded that (±)KU-bound AKR1B1 leads to the attenuation of cellular oxidative stress, as well as the aggressiveness of breast cancer cell migration.

Dual-Loaded Liposomes Tagged with Hyaluronic Acid Have Synergistic Effects in Triple-Negative Breast Cancer.

Triple-negative breast cancer (TNBC) is the most lethal subtypes of breast cancer. Although chemotherapy is considered the most effective strategy for TNBC, most chemotherapeutics in current use are cytotoxic, meaning they target antiproliferative activity but do not inhibit tumor cell metastasis. Here, a TNBC-specific targeted liposomal formulation of epalrestat (EPS) and doxorubicin (DOX) with synergistic effects on both tumor cell proliferation and metastasis is described. These liposomes are biocompatible and effectively target tumor cells owing to hyaluronic acid (HA) modification on their surface. This active targeting, mediated by CD44-HA interaction, allows DOX and EPS to be delivered simultaneously to tumor cells in vivo, where they suppress not only TNBC tumor growth and the epithelial-mesenchymal transition, but also cancer stem cells, which collectively suppress tumor growth and metastasis of TNBC and may also act to prevent relapse of TNBC.

Utilization of Gelling Polymer to Formulate Nanoparticles Loaded with Epalrestat-Cyclodextrin Inclusion Complex: Formulation, Characterization, In-Silico Modelling and In-Vivo Toxicity Evaluation.

Epalrestat (EPL) is an aldose reductase inhibitor with poor aqueous solubility that affects its therapeutic efficacy. The research study was designed to prepare epalrestat-cyclodextrins (EPL-CDs) inclusion complexes to enhance the aqueous solubility by using beta-cyclodextrin (β-CD) and sulfobutyl ether₇ β-CD (SBE7 β-CD). Furthermore, polymeric nanoparticles (PNPs) of EPL-CDs were developed using chitosan (CS) and sodium tripolyphosphate (sTPP). The EPL-CDs complexed formulations were then loaded into chitosan nanoparticles (CS NPs) and further characterized for different physico-chemical properties, thermal stability, drug-excipient compatibility and acute oral toxicity studies. In-silico molecular docking of cross-linker with SBE7 β-CD was also carried out to determine the binding site of the CDs with the cross-linker. The sizes of the prepared NPs were laid in the range of 241.5–348.4 nm, with polydispersity index (PDI) ranging from 0.302–0.578. The surface morphology of the NPs was found to be non-porous, smooth, and spherical. The cumulative percentage of drug release from EPL-CDs loaded CS NPs was found to be higher (75–88%) than that of the pure drug (25%). Acute oral toxicity on animal models showed a biochemical, histological profile with no harmful impact at the cellular level. It is concluded that epalrestat-cyclodextrin chitosan nanoparticles (EPL-CDs-CS NPs) with improved solubility are safe for oral administration since no toxicity was reported on vital organs in rabbits.

Enhanced Oral Bioavailability of Epalrestat SBE7-β-CD Complex Loaded Chitosan Nanoparticles: Preparation, Characterization and in-vivo Pharmacokinetic Evaluation.

BackgroundEpalrestat (EPL) is a carboxylic acid derivative with poor aqueous solubility and its pharmacokinetic features are not fully defined.PurposeCurrent research aimed to fabricate inclusion complexation of EPL with SBE7 β-CD (IC) and EPL/SBE7 β-CD CS NPs (NP).MethodsEPL was complexed with SBE7 β-CD using the co-precipitation method, and the prepared complex was fabricated into nanoparticles using the ionic gelation method. The prepared formulations were characterized for particle size analysis, surface morphology, and in vitro dissolution study. The % inhibition of EPL against α-glucosidase enzyme was also conducted to check the drug’s antidiabetic activity. Finally, an in vivo pharmacokinetic investigation was carried out to determine the concentration of EPL in rabbit plasma of the prepared formulation. In vivo pharmacokinetic studies were conducted by giving a single dose of pure EPL, IC, and NP.ResultsThe size of NP was found to be 241.5 nm with PDI 0.363 and zeta potential of +31.8 mV. The surface of the prepared NP was non-porous, smooth and spherical when compared with pure EPL, SBE7 β-CD and IC. The cumulative drug release (%) from IC and NP was 73% and 88%, respectively, as compared to pure drug (25%). The % inhibition results for in vitro α-glucosidase was reported to be 74.1% and the predicted binding energy for in silico molecular docking was calculated to be −6.6 kcal/mol. The calculated Cmax values for EPL, IC and NP were 4.75±3.64, 66.91±7.58 and 84.27±6.91 μg/mL, respectively. The elimination half-life of EPL was 4 h and reduced to 2 h for IC and NP. The AUC0-α for EPL, IC and NP were 191.5±164.63, 1054.23±161.77 and 1072.5±159.54 μg/mL*h, respectively.ConclusionTaking these parameters into consideration it can be concluded that IC and NP have prospective applications for greatly improved delivery and regulatedt release of poorly water soluble drugs, potentially leading to increase therapeutic efficacy and fewer side effects.

Epalrestat suppresses inflammatory response in lipopolysaccharide-stimulated RAW264.7 cells.

Lipopolysaccharide (LPS) is a potent inducer of inflammatory response. Inflammation is a major risk factor for many diseases. Regulation of inflammatory mediator and pro-inflammatory cytokine levels could be a potential therapeutic approach to treat inflammatory injury. The purpose of the present study was to determine whether epalrestat (EPS), which is used for the treatment of diabetic neuropathy, suppresses inflammatory response in LPS-stimulated RAW264.7 cells. The effects of EPS at near-plasma concentration on the levels of pro-inflammatory cytokines and inflammatory mediators was examined using by MTS assay, quantitative RT-PCR analysis, and western blotting in LPS-stimulated RAW264.7 cells. EPS suppressed mRNA and protein expression levels of pro-inflammatory cytokines, including IL-1β, IL-6, and TNFα, in RAW264.7 cells stimulated with LPS. EPS also affected inflammatory mediators such as iNOS and NF-κB in LPS-stimulated RAW264.7 cells. In this study, we demonstrated for the first time that EPS suppresses inflammatory response in LPS-stimulated RAW264.7 cells. From these results, we propose that targeting the regulation of pro-inflammatory cytokine levels and inflammatory mediators by EPS is a promising therapeutic approach to treat inflammatory injury. It is expected that EPS, whose safety and pharmacokinetics have been confirmed clinically, would be useful for the treatment of inflammatory diseases.

Neuroprotective Effect of Epalrestat on Hydrogen Peroxide-Induced Neurodegeneration in SH-SY5Y Cellular Model.

Epalrestat (EPS) is a brain penetrant aldose reductase inhibitor, an approved drug currently used for the treatment of diabetic neuropathy. At near-plasma concentration, EPS induces glutathione biosynthesis, which in turn reduces oxidative stress in the neuronal cells. In this study, we found that EPS reduces neurodegeneration by inhibiting reactive oxygen species (ROS)-induced oxidative injury, mitochondrial membrane damage, apoptosis and tauopathy. EPS treatment up to 50 μM did not show any toxic effect on SH-SY5Y cell line (neuroblastoma cells). However, we observed toxic effect at a concentration of 100 μM and above. At 50 μM concentration, EPS showed better antioxidant activity against H2O2 (100 μM)-induced cytotoxicity, ROS formation and mitochondrial membrane damage in retinoic acid-differentiated SH-SY5Y cell line. Furthermore, our study revealed that 50 μM of EPS concentration reduced the glycogen synthase kinase-3 β (GSK3-β) expression and total tau protein level in H2O2 (100 μM)-treated cells. Findings from this study confirms the therapeutic efficacy of EPS on regulating Alzheimer's disease (AD) by regulating GSK3-β and total tau proteins phosphorylation, which helped to restore the cellular viability. This process could also reduce toxic fibrillary tangle formation and disease progression of AD. Therefore, it is our view that an optimal concentration of EPS therapy could decrease AD pathology by reducing tau phosphorylation through regulating the expression level of GSK3-β.

Epalrestat suppresses cadmium-induced cytotoxicity through Nrf2 in endothelial cells.

Cadmium (Cd) is an industrial and environmental pollutant that targets the vascular endothelium. The vascular system is critically affected by Cd toxicity. Recent studies have indicated an association between Cd and vascular diseases, although the mechanisms of Cd implications in vascular diseases are not clear. The purpose of the present study was to determine whether epalrestat (EPS), which is used for the treatment of diabetic neuropathy, protects against Cd-induced cytotoxicity in bovine aortic endothelial cells (BAECs). In the present study, the effects of EPS at near-plasma concentration were examined on Cd-induced cytotoxicity in BAECs. Cd-induced cytotoxicity was suppressed by pretreatment with EPS. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a key transcription factor that serves a role in regulating the expression of glutamate cysteine ligase, the rate-limiting enzyme in glutathione (GSH) synthesis. In a previous study, EPS was demonstrated to increase GSH levels in BAECs in association with the Nrf2 pathway. In the present study, EPS increased GSH levels in BAECs exposed to Cd. The protective ability of EPS against the Cd-induced cytotoxicity disappeared following Nrf2 small interfering RNA transfection. In addition, EPS affected the intracellular levels of Cd, Cd transporter ZIP8 and metallothionein. To the best of our knowledge, the current study demonstrated, for the first time, that EPS suppresses Cd-induced cytotoxicity in BAECs. The upregulation of GSH may be associated with the suppression of Cd-induced cytotoxicity by EPS. From these findings, it may be proposed that the regulation of GSH, ZIP8 and metallothionein by EPS is a promising therapeutic approach to prevent Cd-induced toxicity.

Combatting Nitrosative Stress and Inflammation with Novel Substituted Triazinoindole Inhibitors of Aldose Reductase in PC12 Cells Exposed to 6-Hydroxydopamine Plus High Glucose.

Cellular redox dysregulation produced by aldose reductase (AR) in the presence of high blood sugar is a mechanism involved in neurodegeneration commonly observed in diabetes mellitus (DM) and Parkinson's disease (PD); therefore, AR is a key target for treatment of both diseases. The substituted triazinoindole derivatives 2-(3-thioxo-2H-[1,2,4]triazino[5,6-b]indol-5(3H)-yl) acetic acid (cemtirestat or CMTI) and 2-(3-oxo-2H-[1,2,4]triazino[5,6-b]indol-5(3H)-yl) acetic acid (COTI) are well-known AR inhibitors (ARIs). The neuroprotective properties of CMTI, COTI, the clinically used epalrestat (EPA), and the pyridoindole antioxidants stobadine and SMe1EC2 were all tested in the neurotoxic models produced by hyperglycemic glucotoxicity (HG, 75mM D-glucose, 72h), 6-hydroxydopamine (6-OHDA), and HG+6-OHDA models in PC12 cells. Cell viability decreased in all toxic models, increased by 1-5μM EPA, and decreased by COTI at ≥ 2.5μM. In the HG model alone, where compounds were present in the medium for 24h after a continuous 24-h exposure to HG, cell viability was improved by 100nM-5μM EPA, 1-10μM ARIs, and the antioxidants studied, but decreased by EPA at ≥ 10μM. In the 6-OHDA model alone, where cells were treated with compounds for 24h and further exposed to 100μM 6-OHDA (8h), only the antioxidants protected cell viability. In the HG+6-OHDA model, where cells were treated with all compounds (1nM to 50μM) for 48h and exposed to 75mM glucose for 24h followed by incubation with 6-OHDA for 8h, cell viability was protected by 100nM-10μM ARIs and 100-500nM EPA, but not by antioxidants. All ARIs inhibited the HG+6-OHDA-induced increase in iNOS, IL-1β, TNF-α, 3-NT, and total oxidant status at 1-50μM, while increased SOD, CAT, GPx, and total antioxidant status at 1-10μM. EPA and CMTI also reduced the HG+6-OHDA-induced increase in the cellular levels of nuclear factor kB (NF-KB). The neuroprotective potential of the novel ARIs and the pyridoindole antioxidants studied constitutes a promising tool for the development of therapeutic strategies against DM-induced and PD-related neurodegeneration.

Protective Effect of Epalrestat against Oxidative Stress-induced Cytotoxicity

Epalrestat (EPS), approved in Japan, is currently the only aldose reductase inhibitor that is available for the treatment of diabetic neuropathy. Recently, we found that EPS at near-plasma concentration increases the intracellular levels of glutathione (GSH) in rat Schwann cells. GSH, the most abundant non-protein thiol antioxidant in cells, is important for protection against oxidative stress. Oxidative stress is associated with the development and progression of many pathological conditions, such as atherosclerosis, diabetes, and neurodegeneration. In this study, we tested the hypothesis that EPS enhances resistance to oxidative stress, by using rat Schwann cells. To determine whether EPS protects Schwann cells from oxidative stress, we performed experiments by using radical generators, drugs, and heavy metals as the source of oxidative stress. EPS reduced the cytotoxicity induced by 2,2-azobis-[2-(2-imidazolin-2-yl) propane] dihydrochloride, 6-hydroxydopamine, cisplatin, palmitate, cadmium chloride, and manganese (II) sulfate, indicating that EPS plays a role in protecting cells from oxidative stress. We suggest that EPS has the potential to prevent the development and progression of disorders caused by oxidative stress.

AKR1B10 inhibitor enhances the inhibitory effect of sorafenib on liver cancer xenograft

Objective: To investigate the inhibitory effect of AKR1B10 inhibitor combined with sorafenib on hepatocellular carcinoma (HCC) xenograft growth. Methods: HepG2 xenograft model was established in nude mice. The mice were then randomly divided into four groups: control group, epalrestat monotherapy group, sorafenib monotherapy group and combination treatment group. Tumor volume, tumor weight, T/C ratio and the change in body weight of nude mice in each group were compared to evaluate the curative effect. Immunohistochemistry staining was used to detect the expression of Ki-67 in tumor tissues to evaluate the proliferation status of tumor cells. One-way analysis of variance was used to compare the differences between the groups. Student's t-test was used to test means of two groups and chi-square test was used for multiple samples. Results: The differences of the grafted tumor volume before and after treatment between the control group, epalrestat group, sorafenib group and combined therapy group was 238.940 ± 39.813, 124.991 ± 84.670, -26.111 ± 11.518, and -54.072 ± 17.673(mm(3)), respectively, (F = 37.048, P < 0.001). The tumor mass were 0.273 ± 0.140, 0.158 ± 0.078, 0.079 ± 0.054, 0.045 ± 0.024 (g), (F = 16.594, P < 0.001); T/C ratio were 100%, 57.9%, 28.9%, 16.5%, and Ki-67 positive rate were 23.295 ± 6.218, 13.503 ± 3.392, 7.325 ± 2.257, 4.664 ± 1.189 (%), (χ(2) = 822.203, P < 0.001) . The tumor volume (t = -3.579, P = 0.002) and Ki-67 positive rate (t = -10.003, P < 0.001) in epalrestat monotherapy group were significantly lower than control group. The tumor volume (t = 2.056, P = 0.025), tumor mass (t = 2.101, P = 0.043), and Ki-67 positive rate (t = -2.850, P = 0.005) in combination treatment group were significantly lower than sorafenib monotherapy group. Compared with the control group, the body weight of nude mice in the treatment group decreased to a certain extent, but there was no statistically significant difference between epalrestat monotherapy group and control group (t = -1.599, P = 0.262), and combined therapy and sorafenib monotherapy group (t = -0.051, P = 0.96). Conclusion: AKR1B10 inhibitor enhanced the inhibitory effect of sorafenib on hepatocellular carcinoma xenograft.

Influence of Water-soluble polymers on Epalrestat ternary complexation by kneading

The study reported in this current work objected to demonstrate the formation of binary and ternary inclusion complexes of Epalrestat (EP), a poorly water-soluble acidic type drug, with s-cyclodextrin (CD) and with water-soluble polymers PVP K30 and HPMC E4. The solid systems of EP with s-CD and water-soluble polymers were obtained by kneading and characterized for phase solubility, saturation solubility, dissolution, stability studies. FTIR, DSC, PXRD and SEM data indicated the positive influence of s-CD and hydrophilic polymers on EP solubility and dissolution. Phase solubility studies were carried out to evaluate the solubilizing power of CD, with regards to EP in combination with water-soluble polymers, and to determine the apparent stability constants (Ks) and complexation efficiency (CE) of the complexes. Phase solubility studies showed AL (linear) type of solubility curve for the ternary complexes it also showed amelioration in Ks value for ternary complexes. The CE of s-CD towards EP was promoted by water-soluble polymers signifying its use as a ternary component. The dissolution rate of EP and solubility were undoubtedly improved by complexation with s-CD as compared to model drug EP alone. Ternary complexes incorporated with PVP K 30 and HPMC E4 proved better than binary complex. Hence, the water-soluble carrier could be exploited as a ternary component to improve the solubility of EP via s-CD complexation.

Interventional effect of epalrestat on renal interstitial fibrosis in unilateral ureteral obstruction rats and its mechanism

To observe the protective effects of epalrestat (EPS) on interstitial fibrosis in unilateral ureteral obstruction (UUO) rats and its mechanism. Rats were randomly divided into four groups: sham group, UUO group, UUO + epalrestat (50 or 100 mg/kg), 8 rats in each group.Rats in UUO and UUO + epalrestat group were obstructed left ureter.In the sham group, rats had their left ureters exposed and manipulated without ligation.Animals for epalrestat treatment received daily drug via gavage for 3 weeks, the rats of sham and UUO groups received equal amount of sodium carboxymethyl cellulose with the same regimen.Renal tissues pathological changes and collagen deposition were observed by HE and Masson's staining.The aldose reductase(AR) expression in renal tissues was measured by immunohistochemisty.The expression levels of collagen I, collagen III, alpha-smooth muscle actin (α-SMA), fibroblast-specific protein1 (FSP-1), fibronectin (FN), epithelial cadherin (E-cadherin), transforming growth factor-β1 (TGF-β1) and AR from kidney tissues were measured by real-time RT-PCR or Western blot. Compared with the sham group, the renal tissues of the UUO group showed significant fibrosis, including renal tubular epithelial cell atrophy and vacuolated degeneration, collagen deposition, fibroblasts and myofibroblasts proliferation and inflammatory cell infiltration, and concomitantly with the expressions of collagen I, collagen III, TGF-β1, AR, α-SMA, FSP-1 and FN were remarkably up-regulated, but E-cadherin was significantly reduced in UUO group.Compared with the UUO group, after 3 weeks epalrestat administration, the level of renal interstitial fibrosis was obviously ameliorated and the expressions of collagen I, collagen III, TGF-β1, AR, α-SMA, FSP-1 and FN were remarkably down-regulated, but E-cadherin was significantly increased in rats of epalrestat groups. These results suggest that epalrestat attenuates renal interstitial fibrosis possibly through inhibition of EMT via inhibiting TGF-β1 and AR expression.

Assessment of clinical effect of epalrestat combined with lipoic acid on type 2 diabetic peripheral neurology

目的 评价依帕司他联合硫辛酸治疗2型糖尿病周围神经病变的临床疗效。 方法 选取2015年8月至2017年8月解放军第一〇七医院诊治的糖尿病周围神经病变患者112例为研究对象。采用随机数字表法将患者分成两组，对照组54例，治疗组58例。治疗组采取依帕司他联合硫辛酸进行治疗，而对照组则采取硫辛酸单独治疗。比较两组患者治疗前后的临床症状以及神经传导速度。 结果 治疗组、对照组临床总有效率分别为78.6%、45.3%，治疗组明显优于对照组，差异有统计学意义(P 0.05)。治疗后两组神经传导速度均有提升，且治疗组优于对照组，差异有统计学意义(P<0.05)。 结论 硫辛酸联合依帕司他治疗2型糖尿病周围神经病变能够明显提高疗效。

Clinical study of alprostadil combined with epalrestat and methylcobalamin in the treatment of type 2 diabetic peripheral neuropathy

Objective To study the effect of alprostadil combined with epalrestat and methylcobalamin in the treatment of type 2 diabetic peripheral neuropathy. Methods From January 2014 to June 2016, 120 patients with type 2 diabetic peripheral neuropathy in the First People′s Hospital of Baiyin were randomly divided into two groups according to the random number table method.64 patients of the observation group were given the treatment of alprostadil, epalrestat combined with methylcobalamin.56 patients of the control group were given the treatment of alprostadil and methylcobalamin.And the two groups were treated for 4 weeks.The blood glucose, clinical symptoms, adverse reaction, nerve conduction velocity index were compared between the two groups before and after treatment. Results The fasting blood glucose and 2-hour postprandial blood glucose of the two groups after treatment were significantly decreased(t=18.20, 17.61, 15.75, 23.69, all P 0.05). Conclusion Alprostadil combined with epalrestat and methylcobalamin in the treatment of type 2 diabetic peripheral neuropathy has good effect. Key words: Diabetic neuropathies; Alprostadil; Epalrestat; Methylcobalamin

Effect of epalrestat on diabetic peripheral neuropathy: a randomized placebo-controlled trails Meta-analysis

Objective To assess the effect and safety of epalrestat on diabetic peripheral neuropathy(DPN). Methods Retrieved from PubMed, Cochrane Library, CNKI, VIP, CBM and Wanfang database, RCTs about epalrestat in the treatment of DPN were included from establishment to July 2017 and comprehensively evaluated. Two reviewers independently screened literature according to the inclusion and exclusion criteria, extracted data, assessed the risk bias of included studies, and then analysis was performed using the RevMan 5.3 software. Results A total of 14 RCTs involved 1 945 patients were included. The results of systematic review and Meta-analysis showed that epalrestat could significantly improve DPN compared with the placebo/blank control group(OR=8.01, 95%CI: 4.48-14.32, P<0.01; OR=2.49, 95%CI: 1.71-3.65, P<0.01). Compared with the placebo group and the blank control group, epalrestat could significantly improve the median sensory nerve conduction velocity(OR=3.92, 95%Cl: 1.37-6.47, P<0.01), peroneal nerve conduction velocity(OR=4.87, 95%CI: 2.35-7.39, P<0.01) and ulnar nerve conduction velocity(OR=4.58, 95%CI: 2.54-6.63, P<0.01). The major adverse reactions were gastrointestinal reactions, nausea and vomiting, but no serious adverse reactions were observed in the epalrestat group, compared with the placebo/blank control group, the difference was statistically significant(OR=12.87, 95%CI: 2.35-70.50, P<0.01). Conclusion Epalrestat can effectively treat DPN through improving the body's sensory nerve conduction velocity, and it has no serious adverse reactions. Since the limitation of quality and quantity of included studies, large-scale and high-quality randomized double-blinding controlled trails are needed to verify the above conclusion. Key words: Epalrestat; Diabetic neuropathies; Randomized controlled trial; Meta-analysis

NEUROPROTECTIVE EFFECT OF EPALRESTAT ON MEMORY IMPAIRMENT IN STREPTOZOTOCIN-INDUCED TYPE-2 DIABETIC RATS USING DIFFERENT BEHAVIORAL MODELS.

Objective: The present study was designed to evaluate the protective effects of epalrestat (EPS) on memory and learning in type-2 diabetes.Methods: Sixty percent high-fat diet for 2 weeks and a single dose of streptozotocin (35 mg/kg, ip) was used to induce memory impairment in rats. Once the diabetes is confirmed, test drug (EPS - 13.5, 27, and 54 mg/kg, oral) and donepezil (1 mg/kg, oral) were administered to different groups of rats for 4 weeks followed by an assessment of memory and learning deficit using behavioral paradigms: Elevated plus maze (EPM), Morris water maze (MWM), and passive avoidance test.Results: EPS and donepezil showed significant improvement in learning and memory of rats, as indicated by markedly decreased escape latency to reach a hidden platform and increased time spent in target quadrant using MWM task, reduced transfer latency in EPM, and also there is a significant increase in the transfer latencies using passive avoidance test were noted. Memory-enhancing activity of EPS (13.5, 27, and 54 mg/kg) was comparable with the diabetic control group.Conclusion: The study findings suggest that memory-enhancing effect of EPS may be mediated by its antioxidant and anti-inflammatory activities. This recommends the potential effect of EPS therapy as a useful memory restorative agent in the treatment of neurodegenerative disease seen in type-2 diabetes rat.