Analytical and clinical validation of rapid chemiluminescence enzyme immunoassay for urinary thioredoxin, an oxidative stress-dependent early biomarker of acute kidney injury.

BACKGROUND: Oxidative stress is now recognized to be an important therapeutic target in kidney diseases. However, there are currently no biomarkers that can be used clinically to diagnose renal oxidative stress. METHODS: A rapid assay system for urinary thioredoxin 1, an oxidative stress-dependent biomarker of acute kidney injury (AKI), was developed as a chemiluminescence enzyme immunoassay and validated analytically and clinically. RESULTS: Analytic evaluation revealed that hemolytic hemoglobin caused measurements to be abnormally high, above the detectable range. However, urine sediment containing red blood cells did not affect the measurements. Assays using our proposed chemiluminescence enzyme immunoassay were completed within as little as 6 min, whereas a conventional ELISA > 4 h. Aciduria

Historical and pharmacological studies on rehmannia root processing- Trends in usage and comparison of the immunostimulatory effects of its products with or without steam processing and pretreatment with liquor.

ETHNOPHARMACOLOGICAL RELEVANCE: The dried root of Rehmannia glutinosa (RR) is a crude drug used in traditional Japanese Kampo medicine and traditional Chinese medicine (TCM). Sometimes, the crude drug is subjected to additional processing before use. AIM OF THE STUDY: To determine the effects of steam processing and pretreatment with liquor of RR through historical investigation, analytical chemistry, and pharmacological experiments. MATERIALS AND METHODS: We inspected TCM literature from the Later Han Dynasty to the present day. Dried RR steamed for 3, 6, 9, or 12 h (steamed RRs, SRRs), dried RR soaked in yellow rice wine (liquor) (liquor-RR), and dried RR steamed for 6 h pretreated with liquor (liquor-SRR) were prepared. These samples were extracted using boiling water, and the inducible effects of the extracts on granulocyte colony-stimulating factor (G-CSF) secretion in cultured enterocytes and the content of their marker compounds were evaluated by using HPLC. RESULTS: The effect of processing using both steaming and the pretreatment using liquor described in TCM literature over different eras was to enhance the warming effect and tonifying qi (energy) of RR. We found that SRR, processed by pretreatment with liquor, became mainstream since the Qing Dynasty. In SRR, stachyose content was decreased and fructose and manninotriose contents were increased with steaming time. However, the content of these compounds was not altered by pretreatment with liquor. RR extract induced G-CSF secretion in cultured enterocytes; moreover, the SRR extract steamed for more than 6 h had significantly stronger effects than that RR. Pretreatment with liquor did not cause any significant differences in the effects of RR or SRR. CONCLUSIONS: The aim of processing for RR by both steaming and pretreatment with liquor in TCM literature over different eras was to enhance the tonifying effect on qi and its immunostimulatory effect. Although the effect of RR on the induction of G-CSF secretion in intestinal epithelial cells was enhanced by steaming, this enhancement was not enhanced by the pretreatment with liquor. These results provide scientific support for steaming, but could not elucidate a reason for pretreatment with liquor in TCM theory.

Renal redox dysregulation in AKI: application for oxidative stress marker of AKI.

Oxidative stress is a major determinant of acute kidney injury (AKI); however, the effects of an AKI on renal redox system are unclear, and few existing AKI markers are suitable for evaluating oxidative stress. We measured urinary levels of the redox-regulatory protein thioredoxin 1 (TRX1) in patients with various kinds of kidney disease and in mice with renal ischemia-reperfusion injury. Urinary TRX1 levels were markedly higher in patients with AKI than in those with chronic kidney disease or in healthy subjects. In a receiver operating characteristic curve analysis to differentiate between AKI and other renal diseases, the area under the curve for urinary TRX1 was 0.94 (95% confidence interval, 0.90-0.98), and the sensitivity and specificity were 0.88 and 0.88, respectively, at the optimal cutoff value of 43.0 µg/g creatinine. Immunostaining revealed TRX1 to be diffusely distributed in the tubules of normal kidneys, but to be shifted to the brush borders or urinary lumen in injured tubules in both mice and humans with AKI. Urinary TRX1 in AKI was predominantly in the oxidized form. In cultured human proximal tubular epithelial cells, hydrogen peroxide specifically and dose dependently increased TRX1 levels in the culture supernatant, while reducing intracellular levels. These findings suggest that urinary TRX1 is an oxidative stress-specific biomarker useful for distinguishing AKI from chronic kidney disease and healthy kidneys.

Calycosin and formononetin from astragalus root enhance dimethylarginine dimethylaminohydrolase 2 and nitric oxide synthase expressions in Madin Darby Canine Kidney II cells.

Nitric oxide (NO) is a crucial vasodilator produced by nitric oxide synthase (NOS). Asymmetric dimethylarginine (ADMA) is an endogenous NOS inhibitor and mainly catabolized by dimethylarginine dimethylaminohydrolase (DDAH). As we reported, the antihypertensive effect of shichimotsukokato (SKT), a formula of Japanese traditional kampo medicine consisting of 7 crude drugs, in 5/6 nephrectomized rats, is mediated by the DDAH-ADMA-NO pathway. Our present study aimed to explore the effective compounds of SKT using Madin Darby Canine Kidney (MDCK) II cells. We isolated two isoflavones, calycosin and formononetin from astragalus root, one of the components of SKT, which can promote DDAH2 protein and mRNA expressions in MDCK II cells. The neuronal NOS levels were also upregulated by the treatment of calycosin and formononetin. These results suggest that calycosin and formononetin could be the active ingredients of astragalus root and SKT that cause antihypertensive effects. The increased levels of DDAH2 and NOS may enhance NO production, decrease ADMA level and improve endothelial and cardiovascular dysfunction.

Protective effects of Shichimotsu-koka-To on irreversible Thy-1 nephritis.

Oxidative stress and peritubular capillary (PTC) injury are involved in the progression of chronic kidney disease (CKD). We investigated protective effects of Shichimotsu-koka-To (SKT), a Japanese traditional Kampo prescription, against nephrosclerosis and hypertension on a CKD model due to irreversible nephritis. Six-week-old male Wistar rats were subjected to uninephrectomy, and to injection of rabbit anti-thymocyte serum. SKT treatment was continued for 15 weeks, blood pressure was measured, and then renal specimens were collected. PTC networks were detected by immunostaining for CD-31. And superoxide dismutase (SOD)-like activity in the tissue was evaluated. Blood pressure in the SKT group, as well as sham group, was significantly lower than with the vehicle. SKT markedly ameliorated renal function, which was evaluated with urea nitrogen clearance. Compared with the vehicle, SKT treatment lowered both the glomerular enlargement and hyper-cellularity by 80%, and decreased the extracellular matrix area by 75%. SKT treatment also suppressed tubular injury, and maintained PTC networks. Furthermore, SKT recovered SOD-like activity to the basal levels. These results suggest that SKT may be useful for the treatment of CKD during the progression to nephrosclerosis, through the mechanisms of anti-oxidative activity and maintenance of PTC networks.

[Roles of coagulation pathway and factor Xa in chronic kidney disease (CKD)].

Considering that fibrin deposition is observed in glomerulonephritis as well as in diabetic nephropathy, we performed studies to clarify the roles of the coagulation pathway and the active type of coagulation factor X (factor Xa) in the development of chronic kidney disease (CKD) using animal models. Factor Xa activates various cell types through protease-activated receptor 2 (PAR2). Several in vitro studies have demonstrated that PAR2 can mediate factor Xa signaling, but not thrombin signaling. Coagulation processes proceed together with the extracellular matrix (ECM) accumulation through factor V expression in rat Thy-1 nephritis. DX-9065a, a factor Xa inhibitor, suppresses this type of glomerulonephritis. The factor Xa inhibitor danaparoid ameliorated proteinuria, cellular proliferation, and fibrin deposition in lipopolysaccharide (LPS)-triggered activation of High IgA (HIGA) strain of ddY mice. Another factor Xa inhibitor, fondaparinux, suppressed urinary protein, glomerular hypertrophy, and connective tissue growth factor (CTGF), and ECM protein deposition together with angiogenesis in diabetic db/db mice. Finally, in the model of peritoneal fibrosis, fondaparinux treatment decreased the thickness of submesothelial fibrotic tissue and angiogenesis. In consideration of the results to potential human therapy, factor Xa regulation may be promising for the treatment of the aggravation in glomerulonephritis and of the early phase of diabetic nephropathy. In the near future, novel factor Xa inhibitors with the characteristics of oral administration and biliary elimination may appear in the clinical use for treatment of cardiovascular diseases.

Low density lipoprotein apheresis ameliorates interferon-γ production in patients with nephrotic syndrome.

Rapid amelioration of hypercholesterolemia in nephrotic syndrome (NS) using low density lipoprotein-apheresis (LDL-A) sometimes leads to NS remission, along with improvement of impaired biodefense system; however, the mechanism of how LDL-A affects NS is still unknown. We studied IFN-γ production under IL-12 stimulation for 24 h in whole blood from 30 NS patients, 31 non-NS patients, 35 healthy volunteers and another four persistent NS patients due to refractory focal segmental glomerulonephritis and minimal change type nephrotic syndrome. We compared IFN-γ production in whole blood and peripheral blood mononuclear cells (PBMC) from persistent NS patients before and after each of 14 LDL-A procedures. Finally, we studied the effect that persistent NS patients' serum before and after LDL-A had on IFN-γ production in healthy volunteers' PBMC. Whole blood IFN-γ production was significantly lower in NS patients compared with healthy volunteers or non-NS patients. In persistent NS, after LDL-A, IFN-γ production returned to normal levels. IFN-γ production in PBMC varied greatly among these patients and did not show consistent changes after LDL-A. Healthy volunteers PBMC incubated with persistent NS patients' serum obtained after LDLA showed higher IFN-γ production than before LDL-A. IFN-γ production in peripheral blood is impaired if a patient is in a nephrotic state. LDL-A might restore suppressed PBMC function in persistent NS patients, thereby ameliorating the nephrotic state, possibly through removing interfering serum factors.

Anti-hypertensive effects of shichimotsukokato in 5/6 nephrectomized Wistar rats mediated by the DDAH-ADMA-NO pathway.

Shichimotsukokato (SKT) is a Kampo formula, comprising astragalus root, phellodendron bark, rehmannia root, peony root, cnidium rhizome, Japanese angelica root, and uncaria hook. It is prescribed to hypertensive patients who complain of a sensation of a rush of blood to the head, shoulder stiffness, tinnitus, and dull headache. We investigated the effects of SKT on renal hypertension in Wistar rats subjected to a 5/6 nephrectomy (Nx). Systolic blood pressure (SBP) increased markedly after surgery and remained high in the Nx rats. Oral treatment of SKT extract at dosages of 0.75 and 1.5 g/kg/day (corresponding to 5- and 10-fold human dosages, respectively) caused a significant suppression of the increase in SBP in Nx rats. Plasma concentrations of nitric oxide (NO) were marginally lower and asymmetric dimethylarginine (ADMA) significantly higher in the Nx rats than in sham-operated rats. SKT administration caused a significant counteraction of these changes. Finally, we evaluated the levels of protein methyltransferase (PRMT), an enzyme that catalyzes the production of ADMA, and the levels of dimethylarginine dimethylaminohydrolase (DDAH), an enzyme involved in the degradation of ADMA, in the remnant kidney. Neither Nx nor SKT treatment affected PRMT-1 or DDAH-1 levels. DDAH-2 levels were reduced significantly in the Nx rats compared with the sham-operated rats. SKT treatment significantly ameliorated this decrease in the DDAH-2 levels. It is considered that SKT reduced blood pressure in the renal hypertension rat model, mediated, at least partially, by the DDAH-ADMA-NO pathway.

Effects of dye-adsorption solvent on the performances of the dye-sensitized solar cells based on black dye.

The effects of the dye-adsorption solvent on the performances of the dye-sensitized solar cells (DSSCs) based on black dye have been investigated. The highest conversion efficiency (10.6 %) was obtained in the cases for which 1-PrOH and the mixed solvent of EtOH and tBuOH (3:1 v/v) were employed as dye-adsorption solvents. The optimized value for the dielectric constant of the dye-adsorption solvent was found to be around 20. The DSSCs that used MeOH as a dye-adsorption solvent showed inferior solar-cell performance relative to the DSSCs that used EtOH, 1-PrOH, 2-PrOH, and 1-BuOH. Photo- and electrochemical measurements of black dye both in solution and adsorbed onto the TiO(2) surface revealed that black dye aggregates at the TiO(2) surface during the adsorption process in the case for MeOH. Both the shorter electron lifetime in the TiO(2) photoelectrode and the greater resistance in the TiO(2)-dye-elecrolyte interface, attributed to the dye aggregation at the TiO(2) surface, cause the decrease in the solar-cell performance of the DSSC that used MeOH as a dye adsorption solvent.

Serial renal biopsy findings in a case of POEMS syndrome with recurrent acute renal failure.

This report describes a patient presenting with recurrent acute renal failure occurring in the course of POEMS syndrome, a multisystem disease associated with plasma cell dyscrasia. Several combined immunosuppression therapies failed to resolve recurrent acute renal failure; autologous peripheral blood stem cell transplantation was therefore applied. A renal biopsy was performed on each of four occasions when he developed renal dysfunction. The renal biopsy showed typical renal histology of POEMS, membranoproliferative glomerulonephritis-like lesions and narrowing of vessel lumina of various sizes caused by endothelial injury, which progressed to glomerulosclerosis and vessel occlusion. Recurrent acute renal failure might be caused by ischemia due to arterial occlusion. Serum levels of vascular epithelial growth factor (VEGF), which is considered to be a causative factor of endothelial lesions in POEMS syndrome, were not elevated throughout the course of this case.

Roles of coagulation pathway and factor Xa in the progression of diabetic nephropathy in db/db mice.

The active type of coagulation factor X (factor Xa) activates various cell-types through protease-activated receptor 2 (PAR2). We previously reported that a factor Xa inhibitor could suppress Thy-1 nephritis. Considering that fibrin deposition is observed in diabetic nephropathy as well as in glomerulonephritis, this study examined the roles of the coagulation pathway and factor Xa in the development of diabetic nephropathy using type 2 diabetic model mice. Diabetic (db/db) and normoglycemic (m+/m+) mice were immunohistochemically evaluated for their expression/deposition of PAR2, transforming growth factor (TGF)-ß, fibrin, extracellular matrix (ECM) proteins, and CD31 at week 20. Significantly greater numbers of PAR2-positive cells and larger amounts of fibronectin, and collagen IV depositions were observed in the glomeruli of db/db mice than those in m+/m+ mice. Next, expression of PAR2 versus deposition of collagen IV and fibronectin was compared between week 20 and week 30, and the number of PAR2-positive cells in the glomeruli decreased in contrast with the increased accumulation of ECM proteins. In an intervention study, fondaparinux, a factor Xa inhibitor, was subcutaneously administered for ten weeks from week 10 to 20. Fondaparinux treatment significantly suppressed urinary protein, glomerular hypertrophy, fibrin deposition, expression of connective tissue growth factor, and ECM proteins deposition together with CD31-positive capillaries. These results suggest that coagulation pathway and glomerular PAR2 expression are upregulated in the early phase of diabetes, together with the increase of profibrotic cytokines expression, ECM proteins deposition and CD-31-positive vessels. Factor Xa inhibition may ameliorate glomerular neoangiogenesis and ECM accumulation in diabetic nephropathy.

Sairei-to ameliorates rat peritoneal fibrosis partly through suppression of oxidative stress.

BACKGROUND: Sairei-to is a herbal prescription originating from traditional Chinese medicine. We conducted an experimental study on rat peritoneal fibrosis to clarify the suppressive mechanisms of sairei-to. METHODS: Wistar rats were intraperitoneally injected with chlorhexidine gluconate (CG) every day. Peritoneal specimens were collected after 28 days of CG injection and oral administration of sairei-to. Macrophage infiltration, extracellular matrix accumulation, and angiogenesis were evaluated by immunostaining for ED-1, fibronectin, and CD-31, respectively. To observe oxidative stress in the tissue, 4-hydroxy-2-noneal (HNE) accumulation and plasma levels of superoxide dismutase (SOD) activity were detected. As a candidate of antioxidative components in sairei-to, plasma levels of baicalin were determined by high-performance liquid chromatography. RESULTS: Compared with the disease control group, serum total protein levels were significantly recovered in the sairei-to treatment group. Thickness of the submesothelial compact zone, trichrome-stained area, ED-1-positive cells, fibronectin-staining area, and HNE accumulation were suppressed in the treatment group. Concurrently, decreased plasma levels of SOD activity were recovered by sairei-to treatment. Increased CD-31-positive vessel number and area were also suppressed in the sairei-to group. Baicalin was detected in the plasma samples of the sairei-to group at 0.29 ± 0.11 µg/ml (mean±SEM). CONCLUSION: These results suggest that sairei-to ameliorates peritoneal fibrosis, partly through suppressing oxidative stress and macrophage infiltration.

Synthesis of novel beta-diketonate bis(bipyridyl) Os(II) dyes for utilization of infrared light in dye-sensitized solar cells.

Bis(bipyridyl) osmium(II) dyes having a beta-diketonate ligand were synthesized in order to utilize visible and infrared light for dye-sensitized solar cells. Compared to black dye, under AM 1.5 irradiation (100 mW cm(-2)), DSCs using our novel Os dyes exhibited a better spectral response in the near-IR region (by 1050 nm) and showed a higher J(SC) value of 23.7 mA cm(-2).

Churg-Strauss syndrome with severe granulomatous angiitis and crescentic glomerulonephritis, which developed during therapy with a leukotriene receptor antagonist.

A 77-year-old Japanese female developed Churg-Strauss syndrome (CSS), showing fever and numbness in bilateral hands. She was being treated for bronchial asthma with combination inhalant of corticosteroid with beta(2)-agonist, and an oral leukotriene receptor antagonist (LTRA), montelukast, for 15 months. She presented fever up to 38°C with microscopic hematuria and proteinuria, serum creatinine level of 0.7 mg/dl, and C-reactive protein of 11 mg/dl. After referral to our hospital, eosinophilia and high myeloperoxidase (MPO)-antineutrophil cytoplasmic antibody (ANCA) level were observed together with hematuria and proteinuria; renal biopsy examination was performed to clarify the disorder. Renal biopsy specimens showed necrotizing crescent formation, severe granulomatous angiitis in an interlobular artery, and interstitial eosinophilic infiltration. It was noted that nearly intact glomeruli were infiltrated with eosinophils. After treatment with oral prednisolone at initial dose of 40 mg (1 mg/kg body weight), urinary findings rapidly became normal with mild elevation of serum creatinine to 1.5 mg/dl and trace level of serum C-reactive protein in 1 month. Because she was previously treated with montelukast without oral corticosteroid, linkage between CSS and LTRA was highly suspected.

[Case of kidney failure with thrombotic microangiopathy lesions in renal biopsy caused by accelerated hypertension in young adult].

A 19-year-old male was admitted to our hospital for the treatment of severe hypertension with renal dysfunction. Two years before admission, his hypertension had been diagnosed as essential hypertension based on a series of examinations when his renal function was not impaired. Visits to his primary physician ended when he developed severe hypertension of 210/140 mmHg, at which time renal dysfunction and serum creatinine of 2.25 mg/dL were discovered. Renin and antidiuretic hormone were slightly elevated, but renal artery stenosis or other abnormalities were not detected by magnetic resonance imaging and computer tomography. After the hypertension was controlled by medication, a renal biopsy was performed to assess renal impairment. Histology demonstrated lesions compatible with thrombotic microangiopathy (TMA) and ischemic lesions, including fibrinoid necrosis, intimal thickening, occlusion in the small arteries, wrinkling and duplication of the glomerular basement membrane with microthrombi, and focal interstitial fibrosis. Renal function ameliorated after the hypertension was controlled. This case suggests that severe and accelerated hypertension can cause TMA with renal impairment even in young people.

Lipopolysaccharide-triggered acute aggravation of mesangioproliferative glomerulonephritis through activation of coagulation in a high IgA strain of ddY mice.

BACKGROUND: The high IgA (HIGA) strain of ddY mice represents an inbred model of IgA nephropathy that shows mesangioproliferative glomerulonephritis with mesangial IgA deposition. In this study, aggravation of glomerulonephritis in HIGA mice through lipopolysaccharide (LPS)-triggered activation of coagulation was investigated. METHODS: Twelve-week-old HIGA and BALB/c mice were intraperitoneally injected with LPS twice at an interval of 3 days, and kidney specimens were collected 7 days after the second LPS injection. In an intervention experiment, the factor Xa inhibitor danaparoid was injected intraperitoneally every day for 7 days after the first LPS injection. RESULTS: LPS injection induced macrophage infiltration and cellular proliferation in the mesangium together with fibrin deposition and monocyte chemoattractant protein 1 mRNA expression, as well as antigen deposition of tissue factor, factor V, factor X, and protease-activated receptor 2. These phenomena were obvious in HIGA mice when compared to BALB/c mice. Interestingly, toll-like receptor 4 was intensely expressed in HIGA mice before LPS injection and subsequently decreased. Danaparoid treatment significantly ameliorated proteinuria, cellular proliferation, and fibrin deposition. CONCLUSIONS: The present data suggest that tissue factor and factor V induction by LPS may in part accelerate mesangioproliferative glomerulonephritis through activation of factor X and downstream proinflammatory and procoagulant mechanisms.

Tissue factor and factor v involvement in rat peritoneal fibrosis.

OBJECTIVE: Fibrin deposition on the peritoneum has been frequently observed in peritoneal fibrosis induced by long-term peritoneal dialysis. The present study was conducted to clarify the contribution of factor Xa through tissue factor and factor V expression in peritoneal fibrosis. METHODS: Wistar rats were intraperitoneally injected with chlorhexidine gluconate (CG) every day. For the interventional study, the factor Xa inhibitor fondaparinux was subcutaneously administered. After 28 days of CG injection, peritoneal specimens were examined by immunohistochemical analyses and in situ hybridization. RESULTS: The peritoneal submesothelial compact zone was observed to be markedly thicker in the CG-injected groups than in the normal group, and that thickness was dose dependent. Immunohistochemical study revealed massive fibrin, fibronectin, and type IV collagen depositions in the CG-injected groups, which was markedly higher than that in the normal group. Macrophage infiltration and staining for tissue factor, factor V, factor X, and protease-activated receptor-2 were intense in the CG-injected groups and negative/trace in the normal group. Tissue factor and factor V mRNAs were abundant in cells in the thickened peritoneum. A double-labeling experiment revealed that tissue factor was observed mainly in macrophages, and factor V was abundantly distributed in the fibrotic tissue together with macrophages. Fondaparinux treatment decreased the thickness of submesothelial fibrotic tissue, and size and number of CD31-positive vessels. CONCLUSION: These results suggest that expression of tissue factor and factor V in infiltrated macrophages, together with factor X deposition, may progress angiogenesis and accumulation of extracellular matrix components, partly via profibrotic and procoagulant mechanisms in the peritoneum after inflammatory stimulation.

Small animal models of kidney disease: a review.

Animal models of renal disease have provided valuable insights into the pathogenesis of acute and chronic kidney disease. Extension of these models to the mouse has become an increasingly important with the development of gene knockout and transgenic animals. In this review we discuss a range of models that can be used to mimic the mechanisms of human renal disease. While not perfect, the careful and ethical use of these models offers the opportunity to examine individual mechanisms in an accelerated time frame.

Serofendic acid protects from iodinated contrast medium and high glucose probably against superoxide production in LLC-PK1 cells.

BACKGROUND: It is well known that patients with chronic kidney disease, including diabetic nephropathy, often develop cardiovascular diseases. In case of radiographic procedures, reduced renal function may be deteriorated by the use of iodinated contrast medium (CM). This is known as CM-induced nephropathy. In this study, we have focused on the mechanisms of this type of injury in diabetic nephropathy and the preventive effects of serofendic acid. METHODS: We evaluated the cytotoxicity of CM and high glucose on tubular epithelial cells using an LLC-PK1 cell line, and measured cell viability with an alamarBlue assay. We further evaluated superoxide production levels measured by dihydroethidium. We also examined the protective effects of serofendic acid on cytotoxicity with superoxide production of CM and high glucose. RESULTS: CM reduced cell numbers in a dose-dependent and time-dependent manner in LLC-PK1 cells. Furthermore, cytotoxicity of CM in diluted concentration was additively influenced by high glucose. CM and high glucose increased superoxide production, which was evaluated by the response to dihydroethidium, and was suppressed by serofendic acid. Cytotoxicity of CM, high glucose, and H(2)O(2) was suppressed by serofendic acid, as well as the suppression by N-acetylcysteine on CM toxicity. Interestingly, the recovery by serofendic acid in H(2)O(2)- and high glucose-induced cellular injury was to the basal level, in contrast with the partial recovery from CM-induced injury. Finally, serofendic acid suppressed CM-induced injury and high glucose-induced apoptosis. CONCLUSIONS: These results suggest that CM and high glucose induce cytotoxicity and oxidative stress in LLC-PK1 cells and that serofendic acid protects the injury probably from superoxide generation.