Angiotensin-converting enzyme inhibitors attenuated advanced glycation end products-induced renal tubular hypertrophy via enhancing nitric oxide signaling.

Advanced glycation end products (AGE) and angiotensin II were closely correlated with the progression of diabetic nephopathy (DN). Nitric oxide (NO) is a protective mediator of renal tubular hypertrophy in DN. Here, we examined the molecular mechanisms of angiotensin-converting enzyme inhibitor (ACEI) and NO signaling responsible for diminishing AGE-induced renal tubular hypertrophy. In human renal proximal tubular cells, AGE decreased NO production, inducible NOS activity, guanosine 3',5'-cyclic monophosphate (cGMP) synthesis, and cGMP-dependent protein kinase (PKG) activation. All theses effects of AGE were reversed by treatment with ACEIs (captopril and enalapril), the NO donor S-nitroso-N-acetylpenicillamine (SNAP), and the PKG activator 8-para-chlorophenylthio-cGMPs (8-pCPT-cGMPs). In addition, AGE-enhanced activation of extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38 mitogen-activated protein kinase (MAPK) were clearly reduced by captopril, enalapril, SNAP, and 8-pCPT-cGMPs. The abilities of ACEIs and NO/PKG activation to inhibit AGE-induced hypertrophic growth were verified by the observation that captopril, enalapril, SNAP, and 8-pCPT-cGMPs decreased protein levels of fibronectin, p21 Waf1/Cip1 , and receptor for AGE. The results of the present study suggest that ACEIs significantly reduced AGE-increased ERK/JNK/p38 MAPK activation and renal tubular hypertrophy partly through enhancement of the NO/PKG pathway.

Steap4 attenuates high glucose and S100B-induced effects in mesangial cells.

Six-transmembrane epithelial antigen of prostate 4 (Steap4)-knockout mice develop hyperglycaemia and inflammation whereas Steap4 overexpression attenuates atherosclerosis in diabetic mice. Thus, we studied the roles of Steap4 in high glucose (HG, 27.5 mM) or S100B (1 µM, a ligand for the receptor for advanced glycation end-product or RAGE)-induced effects in mouse mesangial (MES13) cells. We found that HG-induced Steap4 protein expression was dependent on S100B. HG increased cell membrane, but not cytosolic, Steap4 protein expression. HG increased protein-protein interaction between Steap4 and S100B, which was confirmed by mass spectrometry of immunoprecipitated S100B. SP600125, LY294002 and AG490 attenuated S100B-induced Steap4 protein expression or gene transcriptional activity. A mutation in signal transducer and activator of transcription 3 (Stat3) site 2 of the Steap4 promoter constructs resulted in a marked decrease in HG or S100B-induced activation of Steap4 gene transcription. Overexpression of Steap4 attenuates HG or S100B-induced collagen IV, fibronectin and cyclooxygenase 2 protein expression. Overexpression of Steap4 attenuates HG or S100B-induced transforming growth factor-ß (TGF-ß). Moreover, overexpression of Steap4 attenuates S100B-induced signalling. Finally, overexpressing Steap4 attenuated renal expression of fibronectin, S100B, TGF-ß, type IV collagen, p-Akt, p-extracellular signal regulated kinase 1/2 and p-Stat3 in streptozotocin-diabetic mice. Thus, overexpression of Steap4 attenuated HG or S100B-induced effects in MES13 cells and attenuated some of S100B-induced effects in diabetic mouse kidneys.

Cinnamaldehyde and nitric oxide attenuate advanced glycation end products-induced the Jak/STAT signaling in human renal tubular cells.

Cinnamaldehyde is a major and a bioactive compound isolated from the leaves of Cinnamomum osmophloeum kaneh. It possesses anti-diabetic properties in vitro and in vivo and has anti-inflammatory and anti-cancer effects. To explore whether cinnamaldehyde was linked to altered advanced glycation end products (AGE)-mediated diabetic nephropathy, the molecular mechanisms of cinnamaldehyde responsible for inhibition of AGE-reduced nitric oxide (NO) bioactivity in human renal proximal tubular cells were examined. We found that raising the ambient AGE concentration causes a dose-dependent decrease in NO generation. Cinnamaldehyde significantly reverses AGE-inhibited NO generation and induces high levels of cGMP synthesis and PKG activation. Treatments with cinnamaldehyde, the NO donor S-nitroso-N-acetylpenicillamine, and the JAK2 inhibitor AG490 markedly attenuated AGE-inhibited NOS protein levels and NO generation. Moreover, AGE-induced the JAK2-STAT1/STAT3 activation, RAGE/p27(Kip1) /collagen IV protein levels, and cellular hypertrophy were reversed by cinnamaldehyde. The ability of cinnamaldehyde to suppress STAT activation was also verified by the observation that it significantly increased SCOS-3 protein level. These findings indicate for the first time that in the presence of cinnamaldehyde, the suppression of AGE-induced biological responses is probably mediated by inactivating the JAK2-STAT1/STAT3 cascade or activating the NO pathway.

Sagittally malrotated kidney: a case series of two patients.

Renal malrotation along the horizontal plane with the long axis of the kidney in the vertical plane can be classified according to an anomalous rotation of the embryologic kidney during ascent. However, renal malrotation along the sagittal plane with the long axis of the kidney in the horizontal plane cannot be explained embryologically and had only been previously reported in one case. Here we report two cases of renal malrotation with the long axis of the kidney in the horizontal plane. Case 1 was a 43-year-old woman with acute pyelonephritis. Right unilateral malrotated kidney was accidentally found in abdominal CT scan and she recovered uneventfully. Case 2 was a 63-year-old diabetic woman with atrial fibrillation, cerebral hemorrhage, sepsis, acute respiratory failure, acute renal failure and right renal infarction. Right unilateral malrotated kidney was accidentally found in abdominal CT scan and she expired within a few days. Thus, these two patients were the 2nd and the 3rd cases of sagittally malrotated kidneys worldwide.

Ubiquitin C-terminal hydrolase-L5 is required for high glucose-induced transforming growth factor-ß receptor I expression and hypertrophy in mesangial cells.

Transforming growth factor-ß (TGF-ß) is pivotal in the pathogenesis of diabetic nephropathy. Type 1 TGF-ß receptor (TGF-ßR1) is degraded by Smad7-dependent ubiquitination-proteasomal pathway, which is deubiquitinated by ubiquitin C-terminal hydrolase-L5 (UCHL5). Therefore, we studied the role of UCHL5 in high glucose (27.8mM)-induced TGF-ßR1 protein expression in mouse mesangial (MES13) cells. UCHL5 short hairpin RNA (shRNA) was used to knock down UCHL5 while LY294002 and the dominant-negative p85 were used to inhibit phosphatidylinositol-3-kinase (PI3K). We found that high glucose increased phospho-Akt, TGF-ßR1 mRNA and protein expression. High glucose also increased UCHL5 protein expression, which was attenuated by LY294002, the dominant-negative p85 and the dominant-negative CREB. High glucose-induced TGF-ßR1 protein expression and TGF-ßR1 protein deubiquitination were attenuated by UCHL5 shRNA. Additionally, high glucose-induced p21(WAF1), fibronectin protein expression and cell hypertrophy were attenuated by UCHL5 shRNA. However, high glucose-induced TGF-ßR1 mRNA, p27(kip1) protein expression and growth inhibition were not affected by UCHL5 shRNA. Finally, glomerular UCHL5 and TGF-ßR1 protein expression were increased in streptozotocin-diabetic rats at 8weeks. We conclude that PI3K-dependent UCHL5 is required for high glucose-induced TGF-ßR1 protein expression in mesangial cells. UCHL5 is also required for high glucose-induced TGF-ßR1 protein deubiquitination, p21(WAF1) and fibronectin protein expression and cell hypertrophy.

BMP-2 suppresses renal interstitial fibrosis by regulating epithelial-mesenchymal transition.

Dysregulation of epithelial-to-mesenchymal transition (EMT) may contribute to renal fibrogenesis. Our previous study indicated that bone morphogenetic protein-2 (BMP-2) significantly reversed transforming growth factor (TGF)-ß1-induced renal interstitial fibrosis. In this study, we examined the underlying mechanism and elucidate the regulation of EMT process under BMP-2 treatment. Cultured renal interstitial fibroblast (NRK-49F) was treated with TGF-ß1 (10 ng/ml) with or without BMP-2 (10-250 ng/ml) for 24 h. The expression of α-smooth muscle actin (α-SMA), E-cadherin, fibronectin, or Snail transcriptional factors was analyzed by immunofluorescence staining or Western blotting. Cell migration was analyzed by wound-healing assay. NRK-49F treated with TGF-ß1 induced significant EMT including upregulatioin of α-SMA, fibronectin, and snail proteins and down-regulation of E-cadherin. Interestingly, co-treatment with BMP-2 dose-dependently reversed TGF-ß1-induced cellular fibrosis, cell migration, and above EMT change. The above effect was closely correlated with Snail since BMP-2 dose- and time-course dependently induced a significant decrease in the level of Snail. Moreover, Snail siRNA significantly reversed TGF-ß1-induced increases in the level of α-SMA and fibronectin (intracellular and extracellular). We suppose that BMP-2 have the potential to attenuate TGF-ß1-induced renal interstitial fibrosis by attenuating Snail expression and reversing EMT process.

Advanced glycation end-products activate extracellular signal-regulated kinase via the oxidative stress-EGF receptor pathway in renal fibroblasts.

Advanced glycation end-products (AGEs), epidermal growth factor receptor (EGFR), reactive oxygen species (ROS), and extracellular signal-regulated kinases (ERK) are implicated in diabetic nephropathy (DN). Therefore, we asked if AGEs-induced ERK protein phosphorylation and mitogenesis are dependent on the receptor for AGEs (RAGE)-ROS-EGFR pathway in normal rat kidney interstitial fibroblast (NRK-49F) cells. We found that AGEs (100 microg/ml) activated EGFR and ERK1/2, which was attenuated by RAGE short-hairpin RNA (shRNA). AGEs also increased RAGE protein and intracellular ROS levels while RAGE shRNA and N-acetylcysteine (NAC) attenuated AGEs-induced intracellular ROS. Hydrogen peroxide (5-25 microM) increased RAGE protein level while activating both EGFR and ERK1/2. Low-dose hydrogen peroxide (5 microM) increased whereas high-dose hydrogen peroxide (100 microM) decreased mitogenesis at 3 days. AGEs-activated EGFR and ERK1/2 were attenuated by an anti-oxidant (NAC) and an EGFR inhibitor (Iressa). Moreover, AGEs-induced mitogenesis was attenuated by RAGE shRNA, NAC, Iressa, and an ERK1/2 inhibitor (PD98059). In conclusion, it was found that AGEs-induced mitogenesis is dependent on the RAGE-ROS-EGFR-ERK1/2 pathway whereas AGEs-activated ERK1/2 is dependent on the RAGE-ROS-EGFR pathway in NRK-49F cells.

Proteinuria versus albuminuria in chronic kidney disease.

Chronic kidney disease (CKD) is defined according to a decrease in the glomerular filtration rate and kidney damage such as proteinuria or albuminuria. Dip-stick proteinuria is only sensitive to albumin and correlates poorly with quantitative 24 h proteinuria, the most commonly used measure in renoprotective randomized controlled clinical trials (RCT). The amount of proteinuria correlates with the efficacy of angiotensin-converting enzyme inhibitors in non-diabetics in RCT. Random urine protein to creatinine ratio (PCR) or albumin to creatinine ratio (ACR) correlates with 24 h urinary excretion. Dip-stick proteinuria correlates poorly with ACR, while PCR correlates reasonably well with ACR. Because of a high analytical variability, efforts are in progress to standardize ACR (but not PCR) measurement. There have been no studies on the direct comparison between proteinuria and albuminuria in terms of utilities (biomarker, surrogate end-point and cost-effectiveness). In this regard, both proteinuria and albuminuria are good biomarkers for cardiovascular events, renal events or mortality. However, there are limitations in RCT regarding the validity of proteinuria or albuminuria as a surrogate end-point. In contrast, measuring proteinuria or albuminuria followed by treatment with angiotensin inhibitors is cost-effective for diabetics, hypertension and aging. CKD guidelines differ in their opinions regarding the choice between ACR and PCR. Based on the current evidence, ACR might be recommended for the diabetics and PCR for the non-diabetics.

Arecoline-induced phosphorylated p53 and p21(WAF1) protein expression is dependent on ATM/ATR and phosphatidylinositol-3-kinase in clone-9 cells.

Betel-quid use is associated with liver cancer whereas its constituent arecoline is cytotoxic, genotoxic, and induces p53-dependent p21(WAF1) protein expression in Clone-9 cells (rat hepatocytes). The ataxia telangiectasia mutated (ATM)/rad3-related (ATR)-p53-p21(WAF1) and the phosphatidylinositol-3-kinase (PI3K)-mammalian target of rapamycin (mTOR) pathways are involved in the DNA damage response and the pathogenesis of cancers. Thus, we studied the role of ATM/ATR and PI3K in arecoline-induced p53 and p21(WAF1) protein expression in Clone-9 cells. We found that arecoline (0.5 mM) activated the ATM/ATR kinase at 30 min. The arecoline-activated ATM/ATR substrate contained p-p53Ser15. Moreover, arecoline only increased the levels of the p-p53Ser6, p-p53Ser15, and p-p53Ser392 phosphorylated p53 isoforms among the known isoforms. ATM shRNA attenuated arecoline-induced p-p53Ser15 and p21(WAF1) at 24 h. Arecoline (0.5 mM) increased phosphorylation levels of p-AktSer473 and p-mTORSer2448 at 30-60 min. Dominant-negative PI3K plasmids attenuated arecoline-induced p21(WAF1), but not p-p53Ser15, at 24 h. Rapamycin attenuated arecoline-induced phosphrylated p-p53Ser15, but not p21(WAF1), at 24 h. ATM shRNA, but not dominant-negative PI3K plasmids, attenuated arecoline-induced p21(WAF1) gene transcription. We conclude that arecoline activates the ATM/ATR-p53-p21(WAF1) and the PI3K/Akt-mTOR-p53 pathways in Clone-9 cells. Arecoline-induced phosphorylated p-p53Ser15 expression is dependent on ATM whereas arecoline-induced p21(WAF1) protein expression is dependent on ATM and PI3K. Moreover, p21(WAF1) gene is transcriptionally induced by arecoline-activated ATM.

Effect of osthole on advanced glycation end products-induced renal tubular hypertrophy and role of klotho in its mechanism of action.

BACKGROUND: Osthole has been widely reported to have pharmacological activities such as anti-cancer, anti-inflammation and anti-hyperlipidemic effects. Klotho was identified as an anti-senescence protein in a variety of tissues. Loss of klotho has been associated with chronic kidney disease. However, potential roles and molecular events for osthole and klotho in diabetic nephropathy remain unclear. PURPOSE: In the current study, we undertook to study the effect of osthole on klotho expression in advanced glycation end products (AGE)-cultured human renal proximal tubular cells, and to investigate the molecular mechanisms of osthole and exogenous klotho against AGE-induced renal tubular hypertrophy. METHODS: Cell viability was elucidated by MTT assay. Protein expression was measured by Western blotting. mRNA level was analyzed by real-time PCR. Cellular hypertrophy growth was evaluated by hypertrophy index. Relative cell size was detected by flow cytometry. RESULTS: We found that raising the ambient AGE concentration causes a dose-dependent decrease in klotho synthesis. Osthole significantly increased AGE-inhibited klotho mRNA and protein expression. Osthole and exogenous klotho treatments significantly attenuated AGE-induced Janus kinase 2 (JAK2)-signal transducers and activators of transcription 1 (STAT1) and STAT3 activation. Moreover, protein levels of suppressor of cytokine signaling 1 (SOCS1) and SOCS3 were augmented by osthole and exogenous klotho. The abilities of osthole and exogenous klotho to reverse AGE-induced cellular hypertrophy were verified by the observation that osthole and exogenous klotho inhibited p21Waf1/Cip1/collagen IV/RAGE expression, total protein content, and cell size. CONCLUSION: Consequently, we found that osthole attenuated AGE-induced renal tubular hypertrophy via induction of klotho expression and suppression of the JAK2-STAT1/STAT3 signaling. These results also showed that klotho might be used as a unique molecular target for the treatment of diabetic nephropathy.

Safflower extract: a novel renal fibrosis antagonist that functions by suppressing autocrine TGF-beta.

Progressive renal disease is characterized by the accumulation of extracellular matrix proteins in the renal interstitium. Hence, developing agents that antagonize fibrogenic signals is a critical issue facing researchers. The present study investigated the blood-circulation-promoting Chinese herb, safflower, on fibrosis status in NRK-49F cells, a normal rat kidney interstitial fibroblast, to evaluate the underlying signal transduction mechanism of transforming growth factor-beta (TGF-beta), a potent fibrogenic growth factor. Safflower was characterized and extracted using water. Renal fibrosis model was established both in vitro with fibroblast cells treated with beta-hydroxybutyrate and in vivo using rats undergone unilateral ureteral obstruction (UUO). Western blotting was used to examine protein expression in TGF-beta-related signal proteins such as type I and type II TGF-beta receptor, Smads2/3, pSmad2/3, Smads4, and Smads7. ELISA was used to analyze bioactive TGF-beta1 and fibronectin levels in the culture media. Safflower extract (SE) significantly inhibited beta-HB-induced fibrosis in NRK cells concomitantly with dose-dependent inhibition of the type I TGF-beta1 receptor and its down-stream signals (i.e., Smad). Moreover, SE dose-dependently enhanced inhibitory Smad7. Thus, SE can suppress renal cellular fibrosis by inhibiting the TGF-beta autocrine loop. Moreover, remarkably lower levels of tissue collagen were noted in the nephron and serum TGF-beta1 of UUO rats receiving oral SE (0.15 g/3 ml/0.25 kg/day) compared with the untreated controls. Hence, SE is a potential inhibitor of renal fibrosis. We suggest that safflower is a novel renal fibrosis antagonist that functions by down-regulating TGF-beta signals.

Effect of taurine on advanced glycation end products-induced hypertrophy in renal tubular epithelial cells.

Mounting evidence indicates that advanced glycation end products (AGE) play a major role in the development of diabetic nephropathy (DN). Taurine is a well documented antioxidant agent. To explore whether taurine was linked to altered AGE-mediated renal tubulointerstitial fibrosis in DN, we examined the molecular mechanisms of taurine responsible for inhibition of AGE-induced hypertrophy in renal tubular epithelial cells. We found that AGE (but not non-glycated BSA) caused inhibition of cellular mitogenesis rather than cell death by either necrosis or apoptosis. There were no changes in caspase 3 activity, bcl-2 protein expression, and mitochondrial cytochrome c release in BSA, AGE, or the antioxidant taurine treatments in these cells. AGE-induced the Raf-1/extracellular signal-regulated kinase (ERK) activation was markedly blocked by taurine. Furthermore, taurine, the Raf-1 kinase inhibitor GW5074, and the ERK kinase inhibitor PD98059 may have the ability to induce cellular proliferation and cell cycle progression from AGE-treated cells. The ability of taurine, GW5074, or PD98059 to inhibit AGE-induced hypertrophy was verified by the observation that it significantly decreased cell size, cellular hypertrophy index, and protein levels of RAGE, p27(Kip1), collagen IV, and fibronectin. The results obtained in this study suggest that taurine may serve as the potential anti-fibrotic activity in DN through mechanism dependent of its Raf-1/ERK inactivation in AGE-induced hypertrophy in renal tubular epithelial cells.

Advanced glycation end-product-inhibited cell proliferation and protein expression of beta-catenin and cyclin D1 are dependent on glycogen synthase kinase 3beta in LLC-PK1 cells.

Glycogen synthase kinase 3beta (GSK3beta) is increased by high glucose in mesangial cells. Thus, we studied the role of GSK3beta in advanced glycation end-product (AGE)-induced effects in the proximal tubule-like LLC-PK1 cells. We found that AGE (100 microg/ml) time-dependently (8-48 h) increased phospho-GSK3beta-Tyr216 (active GSK3beta) and time-dependently (4-24 h) decreased phospho-GSK3beta-Ser21/9 (inactive GSK3beta) protein expression. Meanwhile, AGE (100 microg/ml) activated GSK3beta kinase at 8-48 h. AGE (100 microg/ml) dose-dependently (75-100 microg/ml) decreased beta-catenin protein expression but AGE did not decrease beta-catenin protein expression until 48 h. SB216763 (a GSK3beta inhibitor) and GSK3beta shRNA attenuated AGE (100 microg/ml)-inhibited cell proliferation and protein expression of beta-catenin and cyclin D1 at 48 h. SB216763 also attenuated AGE-induced type IV collagen. We conclude that AGE activates GSK3beta in LLC-PK1 cells. AGE-inhibited beta-catenin and cyclin D1 protein expression are dependent on GSK3beta. Moreover, AGE-inhibited cell proliferation and AGE-induced type IV collagen protein expression are dependent on GSK3beta.

Arecoline-induced growth arrest and p21WAF1 expression are dependent on p53 in rat hepatocytes.

Betel-quid use is associated with the risk of liver cirrhosis and hepatocellular carcinoma and arecoline, the major alkaloid of betel-quid, is hepatotoxic in mice. Therefore, we studied the cytotoxic and genotoxic effects of arecoline in normal rat hepatocytes (Clone-9 cells). Arecoline dose-dependently (0.1-1mM) decreased cell cycle-dependent proliferation while inducing DNA damage at 24h. Moreover, arecoline (1mM)-induced apoptosis and necrosis at 24h. Arecoline dose-dependently (0.1-0.5mM) increased transforming growth factor-beta (TGF-beta) mRNA, gene transcription and bioactivity and neutralizing TGF-beta antibody attenuated arecoline (0.5mM)-inhibited cell proliferation at 24h. Arecoline (0.5mM) also increased p21(WAF1) protein expression and p21(WAF1) gene transcription. Moreover, arecoline (0.5mM) time-dependently (8-24h) increased p53 serine 15 phosphorylation. Pifithrin-alpha (p53 inhibitor) and the loss of the two p53-binding elements in the p21(WAF1) gene promoter attenuated arecoline-induced p21(WAF1) gene transcription at 24h. Pifithrin-alpha also attenuated arecoline (0.5mM)-inhibited cell proliferation at 24h. We concluded that arecoline induces cytotoxicity, DNA damage, G(0)/G(1) cell cycle arrest, TGF-beta1, p21(WAF1) and activates p53 in Clone-9 cells. Moreover, arecoline-induced p21(WAF1) is dependent on p53 while arecoline-inhibited growth is dependent on both TGF-beta and p53.

Slowing renal function decline in chronic kidney disease patients after nephrology referral.

AIM: Late referral of chronic kidney disease (CKD) patients to nephrologists is associated with increased morbidity and mortality and is still quite common and seldom studied in Taiwan because of unique sociocultural factors. We aimed to study the decline in renal function and factors related to the change in renal function before and after referral. METHODS: We retrospectively reviewed the changes of estimated glomerular filtration rate (eGFR) in 213 new referrals of patients with CKD stages 3-5 to the nephrology divisions of one medical centre and one regional hospital from 2001-2006. Data on demographics and laboratory investigations were collected for study. RESULTS: The rates of annual eGFR decline slowed significantly from -7.38 +/- 0.84 before referral to -1.02 +/- 0.45 mL/min per 1.73 m(2)/year after referral (mean +/- standard error of the mean, P < 0.001). The nephrology referral was the most significant factor associated with the slowing of renal function progression, as was younger age and female sex. After nephrology referral, patients with diabetes had an increase in eGFR compared to those without diabetes (P = 0.034). Patients had better control of diastolic blood pressure, sugar and lipid, more frequent use of angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers and statins, less frequent use of non-steroidal anti-inflammatory drugs, and more serum creatinine measurements after nephrology referral. CONCLUSION: Slowing renal functional decline in CKD patients after referral addresses the importance of nephrology referral for CKD care, which should be strongly promoted in CKD prevention projects in Taiwan.

Glomerular Filtration Rates in Asians.

The National Kidney Foundation Kidney Disease Outcomes Quality Initiative guidelines recommended the Modification of Diet in Renal Disease study equation for estimating glomerular filtration rate (GFR) for the classification of CKD, but its accuracy was limited to North American patients with estimated GFR <60 mL/min per 1.73 m2 body surface area of European (White) or African (Black) descent. The Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) developed another equation for estimating GFR, derived from a population that included both participants without kidney disease and with CKD. But many ethnicities were inadequately represented. The International Society of Nephrology, Kidney Disease Improving Global Outcomes committee promulgated clinical practice guidelines, which recommended the CKD-EPI equation. Investigators in Asia subsequently assessed the performance of these GFR estimating equations-the Modification of Diet in Renal Disease study equation, the CKD-EPI equation (creatinine only), and the CKD-EPI equations (creatinine and cystatin C). In this review, we summarize the studies performed in Asia on validating or establishing new Asian ethnicity GFR estimating equations. We included both prospective and retrospective studies which used serum markers traceable to reference materials and focused the review of the performance of GFR estimation by comparisons with the GFR estimations obtained from the CKD-EPI equations.

Betel-quid use is associated with heart disease in women.

BACKGROUND: Betel quid (Areca catechu) is used by approximately 10% of the world population. Betel-quid use is associated with the metabolic syndrome--a risk factor for heart disease. OBJECTIVE: The objective was to test whether betel-quid use is associated with heart disease in adults. DESIGN: Nonpregnant adults aged 20-64 y (n=1932, 52% women) from the nationally representative Nutrition and Health Survey in Taiwan (1993-1996) were studied for independent associations between betel-quid use and heart disease after adjustment for lifestyle factors, age, obesity, diabetes mellitus, hypertension, and concentrations of serum total cholesterol and HDL cholesterol. RESULTS: The prevalence of betel-quid use was higher in men than in women (31% compared with 2.4%; P<0.001). The prevalence of heart disease was not significantly different between men and women (3.3% compared with 2.3%; P=0.12). The prevalence of betel-quid use decreased, whereas the prevalence of heart disease increased, with age. Betel-quid users were younger, drank more, had a lower dietary fruit intake, had a higher Framingham risk score, and had higher serum triacylglycerol concentrations than did the nonusers. At a mean consumption rate of 10 times/d (the third quartile of betel-quid consumption in betel-quid users), betel-quid use was independently associated with the Framingham risk score in subjects without heart disease only if obesity was not included as an adjustment factor (P=0.007). Moreover, the daily rate of betel-quid use was independently associated with prevalent heart disease; the odds ratio associated with a betel-quid consumption rate of 10 times/d was 1.37 (95% CI: 1.1, 1.6; P=0.003) in women. CONCLUSION: Betel-quid use is independently associated with heart disease in women.

Herbal therapy is associated with the risk of CKD in adults not using analgesics in Taiwan.

BACKGROUND: Taiwan has the greatest incidence rate of end-stage renal disease in the world. Several cases of Chinese herb nephropathy were reported in Taiwan. Therefore, we studied the association between herbal therapy and chronic kidney disease (CKD) in Taiwan. STUDY DESIGN: Cross-sectional survey. SETTING & PARTICIPANTS: 1,740 adults in the Nutrition and Health Survey in Taiwan (1993 to 1996). PREDICTOR: Herbal and analgesic therapy. OUTCOMES & MEASUREMENTS: CKD after adjustment for potential confounding variables. RESULTS: Among medication users, prevalences of herbal therapy and analgesic use were 21.6% and 13.2%, respectively. The prevalence of CKD was 9.9%. Participants with CKD were older and had more analgesic use, diabetes, hypertension, and cardiovascular disease. Analgesic use was associated independently and positively with CKD (odds ratio, 2.2; 95% confidence interval, 1.4 to 3.5; P = 0.003) and CKD stage (odds ratio, 2.3; 95% confidence interval, 1.4 to 3.6; P = 0.003). Conversely, herbal therapy was associated independently and positively with CKD (odds ratio, 1.39; 95% confidence interval, 1.2 to 1.7; P = 0.002) and CKD stage (odds ratio, 1.38; 95% confidence interval, 1.1 to 1.7; P = 0.004) only in participants who did not use analgesics. LIMITATIONS: Because this was a cross-sectional study, cause and effect could not be ascertained. CONCLUSIONS: Herbal therapy was associated with CKD in adults in Taiwan who did not use analgesics.

Role of nitric oxide in high glucose-induced mitogenic response in renal fibroblasts.

Nitric oxide (NO) has been suggested to be associated with tubulointerstitial fibrosis in diabetic nephropathy. Abnormal glucose handling in the tubulointerstitium may play an important role in the development of diabetic nephropathy. This study was designed to investigate the effect of NO generation and action in renal fibroblasts exposed to high glucose (HG). We found that HG (500 mg/dl) significantly decreased nitrite production compared with normal glucose (100 mg/dl) when the incubation period was for 12, 18, or 24 h. HG inhibited cGMP-dependent protein kinase (PKG) activation at 4, 8, and 12 h. Both NO donors and PKG activator treatment induced high levels of NO, inducible nitric oxide synthase, and PKG in HG-incubated cells. Interestingly, HG-induced Janus kinase 2-signal transducers and activators of transcription 1 (STAT1) activation but not STAT3 or STAT5 activation at 30 min were blocked by NO donors and PKG activator. Moreover, HG-enhanced Raf-1 and p42/p44 MAPK phosphorylation were markedly suppressed by NO donors or PKG activator. The ability of NO-PKG to inhibit HG-induced cell cycle progression was verified by the observation that NO donors and PKG activator inhibited cdk4 activation and increased p21(Waf1/Cip1) and p16(INK4a) (but not p27(Kip1)) expression in HG-treated renal fibroblasts. Collectively, these data suggest that HG significantly blunted NO signaling, and activation of the NO-PKG pathway may modulate HG-enhanced mitogenic response via specific pathways.

KMUP-1 attenuates high glucose and transforming growth factor-ß1-induced pro-fibrotic proteins in mesangial cells.

We have previously demonstrated that KMUP-1, a xanthine-based nitric oxide enhancer, attenuates diabetic glomerulosclerosis, while increasing renal endothelial nitric oxide synthase expression in rats. However, the anti­fibrotic mechanisms of KMUP­1 treatment in diabetic nephropathy in terms of cell biology and transforming growth factor-ß1 (TGF­ß1) remain unclear. Therefore, the present study involved investigating the effects of KMUP­1 on high glucose (HG) or TGF­ß1­induced pro­fibrotic proteins in mouse mesangial (MES13) cells, and the effects of KMUP­1 on streptozotocin (STZ)­induced diabetic rats. It was identified that KMUP­1 (10 µM) attenuated HG (30 mM)­induced cell hypertrophy while attenuating TGF­ß1 gene transcription and bioactivity in MES13 cells. In addition, KMUP­1 attenuated TGF­ß1 (5 ng/ml)­induced Smad2/3 phosphorylation while attenuating HG or TGF­ß1­induced collagen IV and fibronectin protein expression. Furthermore, KMUP­1 attenuated HG­decreased Suv39h1 and H3K9me3 levels. Finally, KMUP­1 attenuated diabetes-induced collagen IV and fibronectin protein expression in STZ­diabetic rats at 8 weeks. In conclusion, KMUP­1 attenuates HG and TGF­ß1­induced pro­fibrotic proteins in mesangial cells and attenuation of TGF­ß1­induced signaling and attenuation of HG­decreased Suv39h1 expression may be two of the anti-fibrotic mechanisms of KMUP­1.