Kidney protective potential of lactoferrin: pharmacological insights and therapeutic advances

Kidney disease is becoming a global public health issue. Acute kidney injury (AKI) and chronic kidney disease (CKD) have serious adverse health outcomes.However, there is no effective therapy to treat these diseases. Lactoferrin (LF), a multi-functional glycoprotein, is protective against various pathophysiological conditions in various disease models. LF shows protective effects against AKI and CKD.LF reduces markers related to inflammation, oxidative stress, apoptosis, and kidney fibrosis, and induces autophagy and mitochondrial biogenesis in the kidney. Although there are no clinical trials of LF to treat kidney disease, several clinical trials and studies on LF-based drug development are ongoing. In this review, we discussed the possible kidney protective mechanisms of LF, as well as the pharmacological and therapeutic advances. The evidence suggests that LF may become a potent pharmacological agent to treat kidney diseases.

KF-1607, a Novel Pan Src Kinase Inhibitor, Attenuates Obstruction-Induced Tubulointerstitial Fibrosis in Mice

Src family kinases (SFKs), an important group of non-receptor tyrosine kinases, are suggested to be excessively activated during various types of tissue fibrosis. The present study investigated the effect of KF-1607, an orally active and a newly synthesized Src kinase inhibitor (SKI) with proposed low toxicity, in preventing the progression of renal interstitial fibrosis. Unilateral ureteral obstruction (UUO) surgery was performed in 6-week-old male C57BL/6 mice to induce renal interstitial fibrosis. Either KF-1607 (30 mg/kg, oral gavage) or PP2 (2 mg/kg, intraperitoneal injection), a common experimental SKI, was administered to mice for seven days, started one day prior to surgery. UUO injury-induced SFK expression, including Src, Fyn, and Lyn kinase. SFK inhibition by KF-1607 prevented the progression of tubular injury in UUO mice, as indicated by decreases in albuminuria, urinary KIM-1 excretion, and kidney NGAL protein expression. Renal tubulointerstitial fibrosis was attenuated in response to KF-1607, as shown by decreases in α-SMA, collagen I and IV protein expression, along with reduced Masson’s trichrome and collagen-I staining in kidneys. KF-1607 also inhibited inflammation in the UUO kidney, as exhibited by reductions in F4/80 positive-staining and protein expression of p-NFκB and ICAM. Importantly, the observed effects of KF-1607 were similar to those of PP2. A new pan Src kinase inhibitor, KF-1607, is a potential pharmaceutical agent to prevent the progression of renal interstitial fibrosis.

Fyn Kinase: A Potential Therapeutic Target in Acute Kidney Injury

Acute kidney injury (AKI) is a common disease with a complex pathophysiology which significantly contributes to the development of chronic kidney disease and end stage kidney failure. Preventing AKI can consequently reduce mortality, morbidity, and healthcare burden. However, there are no effective drugs in use for either prevention or treatment of AKI. Developing therapeutic agents with pleiotropic effects covering multiple pathophysiological pathways are likely to be more effective in attenuating AKI. Fyn, a nonreceptor tyrosine kinase, has been acknowledged to integrate multiple injurious stimuli in the kidney. Limited studies have shown increased Fyn transcription level and activation under experimental AKI. Activated Fyn kinase propagates various downstream signaling pathways associated to the progression of AKI, such as oxidative stress, inflammation, endoplasmic reticulum stress, as well as autophagy dysfunction. The versatility of Fyn kinase in mediating various pathophysiological pathways suggests that its inhibition can be a potential strategy in attenuating AKI.

Development of Gender-Sensitive Comprehensive Health Matrix: A Comparative Study on the Cases of Sustainable Development Goals Countries and North Korea Based on Gender-Sensitive Indicators

Purpose@#South Korea ranked 18th out of the 162 participating countries in the 2019 report on sustainable development goals (SDGs). Among the 17 specified goals, it has the most difficulty in achieving gender equality (SDG 5). This shortcoming is manifested in the lack of studies on gender-sensitive indicators. The study aims to establish the significance of the development of a comprehensive health matrix to concretize the concept of gender-sensitivity which is often considered as abstract. @*Methods@#An integrated analysis of health determinants was conducted through a convergence study involving medical, social and natural sciences. This analysis was based on both literature reviews and focusgroup discussions. The 6 following focal points were chosen based on the SDGs: gender equality, medicine, education, economy, nutrition, and environment. Objective quantitative indicators were then designated to each of the 6 areas and comparatively analyzed for South Korea, North Korea, and the other SDGs countries. Four areas on sexual and reproductive health were also selected. @*Results@#The results indicated that South Korea scored much lower than North Korea and the other SDGs countries in terms of gender equality. It was also behind North Korea in education, although North Korea had a comparatively lower ranking in the rest of the areas. On the other hand, it fared better than the aforementioned countries with respect to environment, nutrition, medicine, and economy. @*Conclusion@#A comprehensive gender-sensitive health matrix was developed to refine the abstract concept of gender-sensitivity through objective quantitative indicators that assess the health status of a country by means of a scoring system. Gender equality was also confirmed as a common and significant component in the disciplines of sexual and reproductive health and comprehensive health.

Development of Gender-Sensitive Comprehensive Health Matrix: A Comparative Study on the Cases of Sustainable Development Goals Countries and North Korea Based on Gender-Sensitive Indicators

Purpose@#South Korea ranked 18th out of the 162 participating countries in the 2019 report on sustainable development goals (SDGs). Among the 17 specified goals, it has the most difficulty in achieving gender equality (SDG 5). This shortcoming is manifested in the lack of studies on gender-sensitive indicators. The study aims to establish the significance of the development of a comprehensive health matrix to concretize the concept of gender-sensitivity which is often considered as abstract. @*Methods@#An integrated analysis of health determinants was conducted through a convergence study involving medical, social and natural sciences. This analysis was based on both literature reviews and focusgroup discussions. The 6 following focal points were chosen based on the SDGs: gender equality, medicine, education, economy, nutrition, and environment. Objective quantitative indicators were then designated to each of the 6 areas and comparatively analyzed for South Korea, North Korea, and the other SDGs countries. Four areas on sexual and reproductive health were also selected. @*Results@#The results indicated that South Korea scored much lower than North Korea and the other SDGs countries in terms of gender equality. It was also behind North Korea in education, although North Korea had a comparatively lower ranking in the rest of the areas. On the other hand, it fared better than the aforementioned countries with respect to environment, nutrition, medicine, and economy. @*Conclusion@#A comprehensive gender-sensitive health matrix was developed to refine the abstract concept of gender-sensitivity through objective quantitative indicators that assess the health status of a country by means of a scoring system. Gender equality was also confirmed as a common and significant component in the disciplines of sexual and reproductive health and comprehensive health.

Integrative Omics Reveals Metabolic and Transcriptomic Alteration of Nonalcoholic Fatty Liver Disease in Catalase Knockout Mice

The prevalence of nonalcoholic fatty liver disease (NAFLD) has increased with the incidence of obesity; however, the underlying mechanisms are unknown. In this study, high-resolution metabolomics (HRM) along with transcriptomics were applied on animal models to draw a mechanistic insight of NAFLD. Wild type (WT) and catalase knockout (CKO) mice were fed with normal fat diet (NFD) or high fat diet (HFD) to identify the changes in metabolic and transcriptomic profiles caused by catalase gene deletion in correspondence with HFD. Integrated omics analysis revealed that cholic acid and 3β, 7α-dihydroxy-5-cholestenoate along with cyp7b1 gene involved in primary bile acid biosynthesis were strongly affected by HFD. The analysis also showed that CKO significantly changed all-trans-5,6-epoxy-retinoic acid or all-trans-4-hydroxy-retinoic acid and all-trans-4-oxo-retinoic acid along with cyp3a41b gene in retinol metabolism, and α/γ-linolenic acid, eicosapentaenoic acid and thromboxane A2 along with ptgs1 and tbxas1 genes in linolenic acid metabolism. Our results suggest that dysregulated primary bile acid biosynthesis may contribute to liver steatohepatitis, while up-regulated retinol metabolism and linolenic acid metabolism may have contributed to oxidative stress and inflammatory phenomena in our NAFLD model created using CKO mice fed with HFD.

Enrichment of Short-Chain Ceramides and Free Fatty Acids in the Skin Epidermis, Liver, and Kidneys of db/db Mice, a Type 2 Diabetes Mellitus Model

Patients with diabetes mellitus (DM) often suffer from diverse skin disorders, which might be attributable to skin barrier dysfunction. To explore the role of lipid alterations in the epidermis in DM skin disorders, we quantitated 49 lipids (34 ceramides, 14 free fatty acids (FFAs), and cholesterol) in the skin epidermis, liver, and kidneys of db/db mice, a Type 2 DM model, using UPLC-MS/MS. The expression of genes involved in lipid synthesis was also evaluated. With the full establishment of hyperglycemia at the age of 20 weeks, remarkable lipid enrichment was noted in the skin of the db/db mice, especially at the epidermis and subcutaneous fat bed. Prominent increases in the ceramides and FFAs (>3 fold) with short or medium chains (

Carbon monoxide releasing molecule-2 protects mice against acute kidney injury through inhibition of ER stress

Acute kidney injury (AKI), which is defined as a rapid decline of renal function, becomes common and recently recognized to be closely intertwined with chronic kidney diseases. Current treatment for AKI is largely supportive, and endoplasmic reticulum (ER) stress has emerged as a novel mediator of AKI. Since carbon monoxide attenuates ER stress, the objective of the present study aimed to determine the protective effect of carbon monoxide releasing molecule-2 (CORM2) on AKI associated with ER stress. Kidney injury was induced after LPS (15 mg/kg) treatment at 12 to 24 h in C57BL/6J mice. Pretreatment of CORM2 (30 mg/kg) effectively prevented LPS-induced oxidative stress and inflammation during AKI in mice. CORM2 treatment also effectively inhibited LPS-induced ER stress in AKI mice. In order to confirm effect of CO on the pathophysiological role of tubular epithelial cells in AKI, we used mProx24 cells. Pretreatment of CORM2 attenuated LPS-induced ER stress, oxidative stress, and inflammation in mProx24 cells. These data suggest that CO therapy may prevent ER stress-mediated AKI.

Endogenous catalase delays high-fat diet-induced liver injury in mice

Non-alcoholic fatty liver disease (NAFLD) has become the most prevalent liver disease in parallel with worldwide epidemic of obesity. Reactive oxygen species (ROS) contributes to the development and progression of NAFLD. Peroxisomes play an important role in fatty acid oxidation and ROS homeostasis, and catalase is an antioxidant exclusively expressed in peroxisome. The present study examined the role of endogenous catalase in early stage of NAFLD. 8-week-old male catalase knock-out (CKO) and age-matched C57BL/6J wild type (WT) mice were fed either a normal diet (ND: 18% of total calories from fat) or a high fat diet (HFD: 60% of total calories from fat) for 2 weeks. CKO mice gained body weight faster than WT mice at early period of HFD feeding. Plasma triglyceride and ALT, fasting plasma insulin, as well as liver lipid accumulation, inflammation (F4/80 staining), and oxidative stress (8-oxo-dG staining and nitrotyrosine level) were significantly increased in CKO but not in WT mice at 2 weeks of HFD feeding. While phosphorylation of Akt (Ser473) and PGC1α mRNA expression were decreased in both CKO and WT mice at HFD feeding, GSK3β phosphorylation and Cox4-il mRNA expression in the liver were decreased only in CKO-HF mice. Taken together, the present data demonstrated that endogenous catalase exerted beneficial effects in protecting liver injury including lipid accumulation and inflammation through maintaining liver redox balance from the early stage of HFD-induced metabolic stress.

Short-term Treatment of Daumone Improves Hepatic Inflammation in Aged Mice

Chronic inflammation has been proposed as one of the main molecular mechanisms of aging and age-related diseases. Although evidence in humans is limited, short-term calorie restriction (CR) has been shown to have anti-inflammatory effects in aged experimental animals. We reported on the long-term treatment of daumone, a synthetic pheromone secreted by Caenorhabditis elegans in an energy deficient environment, extends the life-span and attenuates liver injury in aged mice. The present study examined whether late onset short-term treatment of daumone exerts anti-inflammatory effects in the livers of aged mice. Daumone was administered orally at doses of 2 or 20 mg/kg/day for 5 weeks to 24-month-old male C57BL/6J mice. Increased liver macrophage infiltration and gene expression of proinflammatory cytokines in aged mice were significantly attenuated by daumone treatment, suggesting that short-term oral administration of daumone may have hepatoprotective effects. Daumone also dose-dependently suppressed tumor necrosis factor-alpha (TNF-alpha)-induced nuclear factor-kappaB (NF-kappaB) phosphorylation in HepG2 cells. The present data demonstrated that short-term treatment of daumone has anti-inflammatory effects in aged mouse livers possibly through suppression of NF-kappaB signaling and suggest that daumone may become a lead compound targeting aging and age-associated diseases.

Plasminogen Activator Inhibitor-1 Antisense Oligodeoxynucleotides Abrogate Mesangial Fibronectin Accumulation

Excessive extracellular matrix (ECM) accumulation is the main feature of chronic renal disease including diabetic nephropathy. Plasminogen activator inhibitor (PAI)-1 is known to play an important role in renal ECM accumulation in part through suppression of plasmin generation and matrix metalloproteinase (MMP) activation. The present study examined the effect of PAI-1 antisense oligodeoxynucleotide (ODN) on fibronectin upregulation and plasmin/MMP suppression in primary mesangial cells cultured under high glucose (HG) or transforming growth factor (TGF)-beta1, major mediators of diabetic renal ECM accumulation. Growth arrested and synchronized rat primary mesangial cells were transfected with 1 microM phosphorothioate-modified antisense or control mis-match ODN for 24 hours with cationic liposome and then stimulated with 30 mM D-glucose or 2 ng/ml TGF-beta1. PAI-1 or fibronectin protein was measured by Western blot analysis. Plasmin activity was determined using a synthetic fluorometric plasmin substrate and MMP-2 activity analyzed using zymography. HG and TGF-beta1 significantly increased PAI-1 and fibronectin protein expression as well as decreased plasmin and MMP-2 activity. Transient transfection of mesangial cells with PAI-1 antisense ODN, but not mis-match ODN, effectively reversed basal as well as HG- and TGF-beta1-induced suppression of plasmin and MMP-2 activity. Both basal and upregulated fibronectin secretion were also inhibited by PAI-1 antisense ODN. These data confirm that PAI-1 plays an important role in ECM accumulation in diabetic mesangium through suppression of protease activity and suggest that PAI-1 antisense ODN would be an effective therapeutic strategy for prevention of renal fibrosis including diabetic nephropathy.

Protective Effects of Lithospermic Acid B on Diabetic Nephropathy in OLETF Rats Comparing with Amlodipine and Losartan / 당뇨병

BACKGROUND: Lithospermic acid B (LAB), an active component isolated from Salvia miltiorrhizae, has been reported to have renoprotective effects in type 1 and type 2 diabetic animal models. We examined the effects of LAB on the prevention of diabetic nephropathy compared with amlodipine, a calcium channel blocker, and losartan, an angiotensin receptor blocker, in Otsuka Long-Evans-Tokushima Fatty (OLETF) rats, an animal model of type 2 diabetes. METHODS: LAB (20 mg/kg), amlodipine (10 mg/kg), or losartan (10 mg/kg) was given orally once daily to 10-week-old male OLETF rats for 28 weeks. RESULTS: None of LAB, losartan, and amlodipine exhibited effects on blood glucose levels. Treatment with amlodipine or losartan resulted in similar reductions in blood pressure; however, LAB was less effective in lowering blood pressure. Albuminuria was markedly suppressed by losartan and LAB, but not by amlodipine. LAB treatment decreased levels of renal lipid peroxidation, monocyte chemoattractant protein-1 (MCP-1), and transforming growth factor-beta1 (TGF-beta1). CONCLUSION: These results suggest that LAB has beneficial effects on the diabetic nephropathy in OLETF rats by decreasing oxidative stress and inflammation as potent as losartan.

Localization of E-cadherin Along the Nephron Segments in the Rat Kidney / 대한해부학회지

E-cadherin is a cell adhesion molecule that is expressed abundantly in the kidney. However, the expression pattern in various renal epithelial cells is not well established. The purpose of this study was to determine the cellular localization along the nephron segments in the rat kidney. Kidneys from adult Sprague Dawley rats were fixed in 4% paraformaldehyde and processed for immunohistochemistry. Bumetanide-sensitive Na+/K+/2Cl- cotransporter (BSC1), thiazide-sensitive Na+/Cl- cotransporter (TSC), calbindin D28k, and H+-ATPase were used to identify the thick ascending, distal convoluted stubule, connecting tubule, and collecting duct, respectively. In the rat kidney, Ecadherin was expressed mainly in the basolateral domain of the collecting duct and papillary surface epithelial cells. The expression level of E-cadherin changed gradually in the connecting tubule and became moderate in the distal convoluted tubule, thick ascending limb, and loop of Henle. The S1 and S2 segment of the proximal tubule showed weak immunoreactivity. However, E-cadherin was not expressed in the S3 segment of the proximal tubule in the rat kidney. These results suggest that E-cadherin is a major adhesion molecule in the collecting duct and papillary surface epithelium, and that E-cadherin may play a critical role in maintaining the epithelial polarity of these nephron segments.

Effect of Bone Morphogenic Protein-7 on Peritoneal Fibrosis / 대한신장학회지

No abstract available.

Effects of Mycophenolic Acid on Oleic Acid- induced Rat Vascular Smooth Muscle Cell Proliferation

PURPOSE: Vascular smooth muscle cell (VSMC) proliferation plays an important role in the development and progression of chronic allograft vasculopathy. Mycophenolic acid (MPA) inhibits various mesenchymal cell proliferation, and reactive oxygen species (ROS) are involved in the anti-pro-liferative effect of MPA. In this study, we investigated the effects of MPA on oleic acid (OA)-induced VSMC proliferation and also the role of ROS in these processes. METHODS: Primary cultured rat VSMCs from Sprague-Dawley were stimulated with OA 100micrometer. MPA 0.1~10micrometer and N-acetylcystein (NAC) 5 mM were administered 1 hour before adding the OA. Cell proliferation was measured by Methylthiazoletetrazolium (MTT) assay, proliferating cell nuclear antigen (PCNA) expression by Western blot analysis, and dichlorofluorescein (DCF)-sensitive cellular ROS by flow cytometry. RESULTS: OA at 100micrometer significantly increased MTT level by 1.6-fold as well as PCNA expression at 48 hours in rat VSMCs. OA also induced DCF-sensitive cellular ROS by 1.6-fold at 5 minutes and the increment of cellular ROS remained for up to 1 hour. MPA at above 1micrometer inhibited OA- induced VSMC proliferation and cellular ROS in a dose-ependent manner. NAC 5 mM also inhibited OA-induced rat VSMC activation. CONCLUSION: These results suggest that MPA inhibits OA-induced VSMC proliferation partially through the inhibition of cellular ROS.

Antifibrotic Effect of BMP-7 in the Peritoneum and the Mechanism / 대한신장학회잡지

PURPOSE: Bone morphogenic protein (BMP)-7, a member of TGF-beta1 superfamily, is an endogenous antifibrotic protein highly expressed in normal kidney. It is not known, however, whether human peritoneal mesothelial cells (HPMC) express BMP-7 or if BMP-7 protects against peritoneal fibrosis and by what mechanism. We examined the effect of BMP-7 overexpression in TGF-beta1-induced epithelial-mesenchymal transition (EMT) of HPMC and in TGF-beta1 signaling in HPMC to elucidate the mechanisms of antifibrotic effect of BMP-7. METHODS: Growth arrested and synchronized HPMC were stimulated with 2 ng/mL of TGF-beta1 to induce EMT. HPMC were transiently transfected with adenovirus-mediated human BMP-7 (AdBMP-7) or with GFP (AdGFP). EMT was defined as downregulation of E-cadherin and upregulation of alpha-smooth muscle actin (SMA). RESULTS: HPMC constitutively expressed BMP-7 mRNA and protein. BMP-7 mRNA and protein expression were significantly inhibited by 50 mM D-glucose, 2x diluted commercial peritoneal dialysis solution, and 2 ng/ml of TGF-beta1. Transfection of AdBMP-7 resulted in 2.5-fold increase in BMP-7 mRNA expression in HPMC. TGF-beta1 significantly decreased E-cadherin and increased alpha-SMA expression in GFP transfected cells. BMP-7 overexpression effectively reversed TGF-beta1-induced E-cadherin and alpha-SMA expression and significantly suppressed TGF-beta1-induced phosphorylation of Smad2/3, ERK1/2, JNK, and p38 MAPK in HPMC as compared to GFP transfected cells. CONCLUSION: BMP-7 is an endogenous antifibrotic protein and downregulation of BMP-7 in HPMC by high glucose, PD solution, and TGF-beta1 may permit the development of peritoneal fibrosis during long-term PD. Our data demonstrate that BMP-7 overexpression reverses TGF-beta1-induced EMT of HPMC and consequent peritoneal fibrosis possibly through inhibition of Smad2/3 and MAPK phosphorylation.

Mechanisms of Epithelial-Mesenchymal Transition of Peritoneal Mesothelial Cells During Peritoneal Dialysis

A growing body of evidence indicates that epithelial-mesenchymal transition (EMT) of human peritoneal mesothelial cells (HPMC) may play an important role in the development and progression of peritoneal fibrosis during long-term peritoneal dialysis (PD) leading to failure of peritoneal membrane function. Here, we review our own observations and those of others on the mechanisms of EMT of HPMC and suggest potential therapeutic strategies to prevent EMT and peritoneal fibrosis during long-term PD. We found that high glucose and H2O2 as well as transforming growth factor-beta1 (TGF-beta1) induced EMT in HPMC and that high glucoseinduced EMT was blocked not only by inhibition of TGF-beta1 but also by antioxidants or inhibitors of mitogen-activated protein kinases (MAPK). Since MAPKs are downstream target molecules of reactive oxygen species (ROS), these data suggest that high glucose-induced generation of ROS and subsequent MAPK activation mediate high glucose-induced EMT in HPMC. We and others also observed that bone morphogenetic protein-7 (BMP-7) prevented EMT in HPMC. Glucose degradation products (GDP) were shown to play a role in inducing EMT. Involvement of a mammalian target of rapamycin (mTOR) in TGF-beta1-induced EMT has also been proposed in cultured HPMC. A better understanding of the precise mechanisms involved in EMT of HPMC may provide new therapeutic strategies for inhibiting peritoneal fibrosis in long-term PD patients.

Effects of Tautomycetin on the Proliferation and Fibronectin Secretion in Vascular Smooth Muscle Cells and Glomerular Mesangial Cells / 대한이식학회지

PURPOSE: Proliferation and extracellular matrix (ECM) accumulation in the vascular smooth muscle cell (VSMC) and glomerular mesangial cell (MC) play key roles in the development and the progression of transplant glomerulosclerosis and chronic allograft nephropathy. Tautomycetin (TMC), a newly developed immunosuppressive agent, induces T-lymphocyte apoptosis through the inhibition of tyrosine kinase and protein phosphatase 1. We examined the effects of TMC on platelet-derived growth factor (PDGF)-induced proliferation and ECM synthesis in cultured VSMCs and MCs of Sprague- Dawley rats, and investigated the molecular mechanisms that are involved. METHODS: Different concentrations of TMC were administered 1 hour before the addition of PDGF 10 ng/mL into the growth-arrested and synchronized cells. Cell proliferation was assessed by methylthiazoletetrazolium (MTT) assay. Caspase-3 cleavage, fibronectin secretion, and the activation of Akt, ERK, and p38 MAPK were assessed by Western blot analysis, respectively. RESULTS: PDGF 10 ng/ mL increased cell proliferation, fibronectin secretion, and the activation of Akt, ERK, and p38 MAPK in both VSMCs and MCs. In both cultured cells, TMC at above 1 microgram/mL significantly reduced basal MTT and increased cleavage caspase-3 in a dose-dependent manner. TMC at 100 ng/mL decreased the PDGF-induced VSMC and MC proliferation without cytotoxicity. However, fibronectin secretion and the activation of Akt, ERK, and p38 MAPK were not affected at this low concentration of TMC, respectively. CONCLUSION: The present data demonstrated that low-dose TMC reduced PDGF-induced VSMC and MC proliferation without affecting the fibronectin secretion and cellular kinase activation.

The Relationship between Serum Creatinine Concentrations and Oxidative Stress or Plasma Levels of Inflammatory Cytokine after Living Donor Renal Transplantation

PURPOSE: Increased oxidative stress and chronic inflammatory process have been substantially linked with the development and progression of chronic renal failure. However, the roles of oxidative stress and inflammation in chronic renal allograft dysfunction are not yet clear. The present study examined the plasma levels of lipid peroxides (LPO), C-reactive protein (CRP), interleukin-6 (IL-6), soluble IL-6 receptor (sIL-6R), transforming growth factor-beta1 (TGF-beta1), and heat shock protein 70 (Hsp 70) as the representative markers of oxidative stress, the inflammatory process and fibrosis among healthy control subjects (kidney donors, n=24), end-stage renal disease (ESRD) patients (n=28), transplant recipients with a serum creatinine (Scr) less than 1.5 mg% (n=30), and transplant recipients with Scr between 1.5 and 5.0 mg% (n=32) during the time at least one year after renal transplantation. METHODS: The plasma LPO concentration was measured by a thiobarbituric acid (TBA) reaction, CRP was measured by latex-enhanced immunonephelometric assay, and TGF-beta1, IL-6, sIL-6R, and HSP 70 were measured by enzyme-linked immunosorbent assay (ELISA), respectively. RESULTS: The Plasma concentrations of LPO, TGF-beta1, Hsp 70, and IL-6 were significantly higher in both the ESRD and renal transplant recipients with Scr levels between 1.5 and 5.0 mg% than in both the healthy controls and transplant patients with Scr levels below 1.5 mg%. Plasma sIL-6R was significantly increased only in the ESRD patients. Among the other 3 groups, the concentrations of sIL-6R were not different between the groups. The plasma CRP concentrations were not different among the 4 study groups. Upon regression analysis, the plasma concentrations of LPO, TGF-beta1, Hsp 70, IL-6 and sIL-6R were positively correlated with the Scr level, respectively. CONCLUSION: Our results demonstrate that the markers of oxidative stress, inflammation and fibrosis were correlated with the Scr level which represents the graft (and native) renal function.

Role of Reactive Oxygen Species and Mitogen-activated Protein Kinases in 2, 3, 7, 8-tetrachlorodibinzo-p-dioxin-induced Fibronectin Secretion by MDCK Cells / 대한신장학회잡지

BACKGROUND: 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD: dioxin) is a potent environmental toxicant that alters various cell function. Both reactive oxygen species (ROS) and mitogen-activated protein kinases (MAPK) mediate dioxin-induced cytotoxicity. Since dioxin was shown to increase renal cell fibronectin secretion in a dose-dependent manner and ROS and MAPK also play roles in fibronectin upregulation in renal cells, the present study examined whether ROS and/or MAPK activation play a role in dioxin-induced fibronectin upregulation in tubular epithelial cells. METHODS: Madin-Darby canine kidney (MDCK) cells were cultured with minimum essential medium (MEM) containing 10% fetal bovine serum. Growth arrested and synchronized MDCK cells by serum deprivation were stimulated with dioxin 1 nM in the presence or absence of extracellular signal-regulated protein kinase (ERK) inhibitor PD98059 50 microM, p38 MAPK inhibitor 100 nM, trolox 500 microM, or taurine 500 microM for up to 48 hours. Dichlorofulorescein (DCF)-sensitive cellular ROS was measured by FACScan and fibronectin in the media and cellular MAPK by a Western blot analysis. RESULTS: Dioxin 1 nM significantly increased cellular ROS and fibronectin in MDCK cells. Antioxidants, trolox and taurine, effectively inhibited dioxin-induced cellular ROS and fibronectin secretion. Dioxin increased phosphorylation of ERK at 5 minutes and P38 MAPK at 48 hours. Dioxin did not affect c-Jun NH2-terminal kinase (JNK) activation for up to 48 hours. Both PD98059 and p38 MAPK inhibitor suppressed dioxin-induced fibronectin secretion by MDCK cells. CONCLUSION: These data suggest that dioxin increases fibronectin secretion by renal distal tubular epithelial cells through ROS and MAPK (ERK and p38 MAPK) and this may lead to renal fibrosis.