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Hung-Chun Chen

Publications and source records attributed to Hung-Chun Chen.

35 records · Page 2Linked to original sources
PubMed2005

Alterations of glomerular and extracellular levels of glutathione peroxidase in patients and experimental rats with diabetic nephropathy.

To investigate the status and role of glutathione peroxidase (GPX) in diabetic nephropathy, we measured GPX in the plasma and urine of 14 patients with diabetic glomerulosclerosis (DGS) and measured glomerular GPX immunostaining in these patients and in rats with streptozotocin-induced diabetes of varying duration. Plasma GPX levels were significantly lower in DGS patients than in diabetic patients without nephropathy (P < .05) or normal controls (P < .01). Urinary GPX concentrations were also significantly lower in DGS patients than in diabetic patients without nephropathy or normal controls (both P < .05). Immunostaining of glomerular GPX was significantly less in DGS patients than in normal controls (P < .05) and was negatively correlated with the glomerular sclerosis score and the index of mesangial expansion. Serial examination of glomerular GPX in diabetic rats showed that immunostaining scores for glomerular GPX in rats were significantly lower than those in normal control rats after 1 and 3 months' duration of diabetes, and staining scores were also significantly lower in rats killed after 3 months of diabetes than in those killed after 1 week. In conclusion, our study demonstrates that GPX concentrations in plasma, urine, and glomeruli are decreased in individuals with DGS and that the immunostaining of glomerular GPX decreases progressively.

Adult↗
PubMed2005

Increased glomerular and extracellular malondialdehyde levels in patients and rats with diabetic nephropathy.

Results from animal experiments have suggested that reactive oxygen species (ROS) play an important role in tissue damage associated with diabetes. To determine whether ROS are involved in patients with diabetic nephropathy, we measured the plasma and urinary levels of malondialdehyde (MDA), an important marker of lipid peroxidation, and assessed the immunoreactivity of MDA and superoxide dismutase (SOD) in glomeruli of patients and experimental rats with diabetic nephropathy. Both plasma and urinary MDA levels were significantly higher in patients with diabetic glomerulosclerosis (DGS) than those of diabetic patients without proteinuria, proteinuric patients without diabetes, and normal controls. In DGS patients, the plasma MDA was significantly correlated with urinary MDA (p<0.05). The urinary MDA, but not plasma MDA, was significantly correlated with the degree of glomerulosclerosis and the index of mesangial expansion (both p<0.01) in DGS patients. The immunostaining score of glomerular MDA and SOD were also significantly higher in DGS patients than in control kidneys. In rats with diabetes for more than one month, the glomerular immunostaining for both MDA and SOD were also significantly higher than in controls rats, and both were increased with the progression of diabetes. Our results suggest that oxidative stress is involved in the pathogenesis and the progression of DGS.

Adolescent↗
PubMed2005

HCV infection complicated with nephrotic syndrome, immune complex crescentic glomerulonephritis and acute renal failure: a case report.

There is ample evidence suggesting that hepatitis C virus (HCV)-associated autoimmunity plays a role in a broad spectrum of autoimmune diseases, which are usually overlooked. We report on a case of nephrotic syndrome, palpable purpura, cryoglobulinemia, hypocomplementemia, and acute renal failure complicated by immune complex glomerulonephritis (GN). The patient is a 64-year-old man with HCV infection, who was initially considered to present only an HCV-associated cryoglobulinemic GN. However, renal biopsy revealed a "full house" immune complex crescentic GN, which led to our subsequent investigation. The attending clinicians faced what is a common dilemma, where an HCV-associated autoimmune disease inevitably switches to a lupus-like GN. Hence, we also discuss treatment.

Acute Kidney Injury↗
PubMed2005

Allopurinol-induced severe hypersensitivity with acute renal failure.

A 62-year-old male was sent to the emergency room due to a high fever and generalized skin rash after taking allopurinol for 9 days. Physical examination was normal except for the generalized skin rash presenting with erythematous macules. Complete blood count showed leukocytosis with eosinophilia. Blood biochemistry showed impaired renal and hepatic function. Pathologic examination concluded that the skin rash was erythema multiforme. These findings met the diagnostic criteria for allopurinol-induced hypersensitivity syndrome (AHS). Our patient not only had the most common skin lesion but soon developed acute renal failure that required intermittent hemodialysis, despite rapid discontinuation of allopurinol and adequate hydration and steroid therapy. No other causes of acute renal failure were found. Renal impairment was the worst part of the patient's condition and he never completely recovered. AHS should be considered in the differential diagnosis of acute renal and hepatic failure in patients with evidence of allergy and recent use of allopurinol.

Acute Kidney Injury↗
PubMed2005

Role of lipid control in diabetic nephropathy.

Patients with diabetic nephropathy are known to be associated with many lipoprotein abnormalities, including higher plasma levels of very low-density lipoprotein, low-density lipoprotein and triglycerides, and lower levels of high-density lipoprotein. Many studies have reported that lipids may induce both glomerular and tubulointerstitial injury through mediators such as cytokines, reactive oxygen species, chemokines, and through hemodynamic changes. Clinical studies in patients with diabetic nephropathy showed that lipid control can be associated with an additional effect of reduction in proteinuria. Experimental studies demonstrated that lipid-lowering agents exerted a certain degree of renoprotection, through both indirect effects from lipid lowering and a direct effect on cell protection. Therefore, lipid control appears to be important in the prevention and treatment of diabetic nephropathy. Diabetic nephropathy has become the leading cause of end-stage renal failure in many countries, including Taiwan. One of the major risk factors for the development and progression of diabetic nephropathy is dyslipidemia. In this paper we will review the role of lipid in mediating renal injury and the beneficial effects of lipid control in diabetic nephropathy.

Diabetic Nephropathies↗
PubMed2004

Leptin and connective tissue growth factor in advanced glycation end-product-induced effects in NRK-49F cells.

Previously, we showed that Janus kinase 2 (JAK2) is important in advanced glycation end-product (AGE)-induced effects in renal interstitial (NRK-49F) fibroblasts. Leptin is a JAK2-activating cytokine via the long form leptin receptor (Ob-Rb). Leptin and connective tissue growth factor (CTGF) may be involved in renal fibrosis. However, the relationship between leptin and CTGF in terms of AGE-induced effects remains unknown. Thus, the effects of AGE (150 microg/ml) and leptin on mitogenesis, CTGF and collagen expression in NRK-49F cells were determined. We found that leptin and AGE increased mitogenesis and type I collagen protein expression at 3 and 7 days, respectively. AGE increased leptin mRNA and protein expression at 2-3 days. AGE increased CTGF mRNA and protein expression at 3-5 days. AG-490 (JAK2 inhibitor) abrogated AGE-induced leptin mRNA and protein expression at 2-3 days. AG-490 and Ob-Rb anti-sense oligodeoxynucleotides (ODN) abrogated AGE-induced CTGF mRNA and protein expression at 3-5 days. AG-490 and CTGF anti-sense ODN abrogated AGE-induced mitogenesis and collagen protein expression at 7 days. Additionally, leptin dose (0.2-1 microg/ml) and time (1-2 days)-dependently increased CTGF protein expression. AG-490 abrogated leptin (1 microg/ml)-induced CTGF protein expression at 2 days. AG-490 and CTGF anti-sense ODN abrogated leptin-induced mitogenesis and collagen protein expression at 3 days. We concluded that AGE induced JAK2 to increase leptin while leptin induced JAK2 to increase CTGF-induced mitogenesis and type I collagen protein expression in NRK-49F cells. Additionally, AGE-induced mitogenesis and type I collagen protein expression were dependent on leptin-induced CTGF.

Animals↗
PubMed2004

1-alpha,25-Dihydroxyvitamin D3 regulates inducible nitric oxide synthase messenger RNA expression and nitric oxide release in macrophage-like RAW 264.7 cells.

The expression of inducible nitric oxide synthase (iNOS) expression and release of nitric oxide (NO) from macrophages are markedly increased in granulomatous infections. Activation of macrophages 1alpha-hydroxylase results in an increase of 1alpha,25-dihydroxyvitamin D(3) [1,25(OH)(2)D(3)]. However, the significance of this increased production is not completely understood. In this study, we analyzed 1,25(OH)(2)D(3) and NO production in patients with tuberculosis infection and hypercalcemia and used lipopolysaccharide (LPS) to stimulate RAW 264.7 cells in an attempt to assess iNOS expression and gaseous NO production regulated by 1,25(OH)(2)D(3). Peroxynitrite (OONO(-)) production and lactate dehydrogenase activity were also examined. Without additional stimulation, peripheral-blood mononuclear cells (PBMCs) from patients with tuberculosis converted more 25-hydroxyvitamin D(3) to 1,25(OH)(2)D(3) than did those from normal controls. These PBMCs released less NO than did those from control subjects, at baseline and in the stimulated state. We found that 1,25(OH)(2)D(3) dose-dependently inhibited iNOS messenger RNA expression of the LPS-stimulated RAW 264.7 cells and also significantly reduced the gaseous NO release and OONO(-) production. Paralleling the 1,25(OH)(2)D(3)-induced inhibition of NO release were reductions in OONO(-) and LDH production. In conclusion, 1,25(OH)(2)D(3) inhibited iNOS expression and reduced NO production by LPS-stimulated macrophages in the range of physiological doses. Inhibition of the NO surge was coupled with a reduction in OONO(-) and LDH production. Increased 1,25(OH)(2)D(3) production and decreased release of NO from the PBMCs of patients with tuberculosis and hypercalcemia were also noted. We propose that 1,25(OH)(2)D(3) production by macrophages may protect themselves against oxidative injuries caused by the NO burst. In the case of tuberculosis infection, increased 1,25(OH)(2)D(3) synthesis may further contribute to the development of an unwanted phenomenon-hypercalcemia.

Animals↗
PubMed2003

Beta-hydroxybutyrate-induced growth inhibition and collagen production in HK-2 cells are dependent on TGF-beta and Smad3.

BACKGROUND: Ketonuria is common in diabetes. The major form of ketone body is beta-hydroxybutyrate (beta-HB), which is metabolized by the proximal tubule. Transforming growth factor beta (TGF-beta) and tubulopathy are important in diabetic nephropathy. Thus, the role of TGF-beta and the downstream Smad3 in beta-HB-induced effects in the human proximal tubule (HK-2 cell) was studied. METHODS: Effects of beta-HB (0.1 to 10 mmol/L) on HK-2 cells were determined for: proliferation, cell cycle distribution, collagen production, tubular transdifferentiation [expression of alpha-smooth muscle actin (alpha-SMA) protein], TGF-beta, Smad2/3, p21WAF1, and p27kip1. RESULTS: Beta-HB (0.1 to 10 mmol/L) dose dependently decreased proliferation, arrested the cells in G0/G1 phase of the cell cycle, and increased p21WAF1/p27kip1 protein expression at 48 hours (without affecting p21WAF1/p27kip1 mRNA and transcription). beta-HB (1 mmol/L) increased p21WAF1/p27kip1 protein half-lives. Beta-HB (1 mmol/L) increased TGF-beta transcription at 24 hours and TGF-beta1 mRNA/bioactivity at 48 hours. Beta-HB (1 mmol/L) increased nuclear Smad2/3 protein expression and increased collagen production (without affecting tubular transdifferentiation), which were reversed by Smad7, dominant-negative Smad3, and N-acetylcysteine. Dominant-negative Smad3 reversed beta-HB-induced TGF-beta transcription at 24 hours, and reversed TGF-beta1 bioactivity at 48 hours. Dominant-negative Smad3 reversed beta-HB-induced p21WAF1/p27kip1 protein expression at 48 hours. Finally, N-acetylcysteine, TGF-beta antibody, Smad7, and dominant-negative Smad3 reversed beta-HB (1 mmol/L)-induced growth inhibition at 48 hours. CONCLUSION: Beta-HB activated Smad 2/3 by oxidative stress. TGF-beta and Smad3 mediate beta-HB-induced cell cycle-dependent growth inhibition while Smad3 mediate beta-HB-induced collagen production and p21WAF1/p27kip1 protein expression in HK-2 cells. Moreover, beta-HB increased p21WAF1/p27kip1 protein expression by increasing p21WAF1/p27kip1 protein stability.

3-Hydroxybutyric Acid↗
PubMed2003

High blood glucose and osmolality, but not high urinary glucose and osmolality, affect neuronal nitric oxide synthase expression in diabetic rat kidney.

We recently demonstrated that neuronal nitric oxide synthase (nNOS) messenger RNA (mRNA) is markedly increased in the kidneys of diabetic rats and water-deprived rats. It can be inferred that high plasma glucose and osmolality and high renal tubular glucose and osmolality are somehow involving in renal NOS synthesis in diabetic rats. Phlorizin, a competitive inhibitor of glucose transport in the proximal tubule, causes renal glycosuria in nondiabetic rats and reverses hyperglycemia in diabetic rats. To further investigate whether high plasma glucose and osmolality or high renal tubular glucose and osmolality influence renal NOS synthesis in diabetic rats, we measured nNOS mRNA levels in phlorizin-treated normal and diabetic rats. Neuronal NOS mRNA expression in the kidneys was not significantly different between normal rats and phlorizin-treated normal rats with high urinary glucose and osmolality. The phlorizin-treated diabetic rats showed a significant decrease in the ratio of nNOS to beta-actin mRNA compared with diabetic rats. On linear-regression analysis, plasma glucose was strongly positively correlated with nNOS mRNA expression in the cortex, outer medulla, and inner medulla (r(2) =.378, r(2) =.680, and r(2) =.445, respectively) of rat kidneys. Neither urine glucose concentration nor urine osmolality was correlated with nNOS mRNA expression in rat kidneys. In conclusion, our results indicate that nNOS mRNA expression in the kidneys of diabetic rats is directly affected by high blood glucose/osmolality but not by high urinary glucose or osmolality.

Actins↗
PubMed2002

Pravastatin suppress superoxide and fibronectin production of glomerular mesangial cells induced by oxidized-LDL and high glucose.

Pravastatin is a potent inhibitor of HMG-CoA reductase and is effective in lowering serum lipid levels. Recent studies have shown that pravastatin also reduces oxidative modification of LDL and decreases albuminuria in patients with diabetes. To determine the possible benefit of pravastatin on the diabetic kidney, we have measured the effects of pravastatin on the proliferation and the production of superoxide and fibronectin, and the expression of fibronectin mRNA of glomerular mesangial cells stimulated by oxidized-LDL and high glucose. Our results demonstrated that the [(3)H]-labeled thymidine uptake of mesangial cells decreased after oxidized-LDL stimulation (50 microg/ml, 6 h) and increased after high glucose stimulation (25 mM, 48 h). The production of superoxide and fibronectin and the expression of fibronectin mRNA of glomerular mesangial cells were all significantly increased after stimulation with either oxidized-LDL or high glucose, or the combination of oxidized-LDL and high glucose. Pravastatin (100 microM, 48 h) alone had no effect on unstimulated cells. However, pravastatin significantly reversed thymidine uptake, inhibited the production of superoxide and fibronectin, and inhibited the expression of fibronectin mRNA of glomerular mesangial cells after stimulation with either oxidized-LDL or high glucose. Our results indicate that pravastatin may effect as an antioxidant and may suppress fibronectin synthesis of glomerular mesangial cells in diabetic patients with hyperlipidemia.

Animals↗
PubMed2002

Risk factors and risk for mortality of mild hypoparathyroidism in hemodialysis patients.

Relative hypoparathyroidism (parathyroid hormone [PTH] < or = 200 pg/mL) is prevalent in hemodialysis (HD) patients, with unknown pathogenesis and prognosis. Thus, to clarify risk factors and prognosis of time-dependent relative hypoparathyroidism in HD patients, a retrospective cohort study was performed for 126 HD patients with four or more PTH determinations and no previous total or subtotal parathyroidectomy. Values for intact PTH, ionized calcium, phosphate, magnesium, albumin, creatinine, urea reduction ratio (URR), glucose, hemoglobin A1c (HbA1c), aluminum, and 1,25(OH)2D were obtained at enrollment and at some time during follow-up. The prevalence of relative hypoparathyroidism at entry was 76 of 126 patients (60.3%). Univariate analysis showed that patients with hypoparathyroidism were older, more likely to have diabetes, and had greater ionized calcium levels and lower phosphate, albumin, blood urea nitrogen (BUN), and creatinine levels. Patients with diabetes were older and had a shorter duration of dialysis therapy and lower PTH, phosphate, albumin, BUN, and creatinine levels and URRs. Conversely, multivariate analysis showed that PTH levels at entry were associated directly with creatinine levels and inversely with age and ionized calcium levels (but not diabetes). During follow-up, PTH levels fluctuated concomitantly with ionized calcium and phosphate levels over time in all patients. Time-dependent PTH levels were associated directly with duration of dialysis therapy and use of vitamin D and phosphate and albumin levels, but inversely with age and ionized calcium and magnesium levels (but not glucose or HbA1c levels). Interestingly, time-dependent PTH levels were independently associated with survival after adjusting for traditional risk factors (diabetes, age, albumin and creatinine levels, and URR) and duration of dialysis therapy. We conclude that in HD patients, relative hypoparathyroidism was not associated with diabetes per se. Time-dependent PTH levels were associated with age, duration of dialysis, and levels of ionized calcium, phosphate, albumin, and magnesium. Moreover, relative hypoparathyroidism at entry and lower time-dependent PTH levels predict mortality.

Age Factors↗
PubMed2002

Effects of pravastatin on superoxide and fibronectin production of mesangial cells induced by low-density lipoprotein.

Pravastatin is a potent inhibitor of HMG-CoA reductase and is effective in lowering serum lipid levels. Recent studies have shown that pravastatin also reduces the oxidative modification of low-density lipoprotein (LDL). To determine whether pravastatin has a direct effect on glomerular mesangial cells, we have measured the effects of pravastatin on the production of superoxide and fibronectin of glomerular mesangial cells stimulated by LDL. Our results demonstrated that the superoxide production of mesangial cells increased after LDL stimulation (100 microg/ml for 4 h) and that the superoxide production was significantly suppressed by either superoxide dismutase (SOD; 500 U/ml for 36 h; p < 0.01) or pravastatin (80 microM for 36 h; p < 0.05). The production of fibronectin was also increased after LDL stimulation which was also significantly suppressed by either SOD (p < 0.01) or pravastatin (p < 0.01). SOD or pravastatin alone had no effect on the unstimulated cells. Our results indicate that pravastatin may have a direct effect as an antioxidant and suppresses the fibronectin synthesis of glomerular mesangial cells independent of its hypolipidemic effect.

Animals↗
PubMed2002

Changes of renal cortical Na-K ATPase activity, protein, and mRNA expression in ureteral obstruction.

Decreased renal Na-K ATPase activity in ureteral obstruction contributes to tubular sodium reabsorption defect in obstructive nephropathy. The integrated changes on the enzyme activity, protein number, and mRNA level of renal cortical Na-K ATPase, in response to bilateral or unilateral ureteral obstruction (BUO & UUO), were studied in rabbits. Ouabain-sensitive Na-K ATPase activities of renal cortex were significantly decreased at 24 h after BUO and further decreased at 48 h. The unobstructed contra-lateral kidney had significantly higher Na-K ATPase activity compared to the obstructed side. Immunoblots of Na-K ATPase alpha and beta subunits protein were both decreased at 24 h of BUO and further decreased at 48 h. The levels of Na-K ATPase beta subunit mRNA showed to be significantly decreased at 12 h after obstruction and further decreased at 24 and 48 h. However, the levels of alpha subunit mRNA were not changed as that of beta subunit throughout the study period. This study also used a newly developed method for release of obstruction. All the parameters studied above recovered to variable extents after release of the ureteral obstruction. In summary, decreases in Na-K ATPase activity, protein, and mRNA in obstructed kidney are specific cellular responses to ureteral obstruction. The degree of down-regulation is related to the duration of obstruction. The reduced activity of Na-K ATPase can be explained by decreased enzyme protein. However, the discordant findings in Na-K ATPase subunits protein amounts and mRNA changes suggest that renal Na-K ATPase subunits have different cellular regulatory processes to obstruction, in which transcriptional, translational and even intra-cytoplasmic processing may be involved.

Animals↗
PubMed2002

Nail-patella syndrome with renal involvement and antecubital pterygia.

Nail-patella syndrome (NPS) is a rare, autosomal-dominant hereditary disorder characterized by nail dysplasia and multiple osseous abnormalities. Some patients may develop renal function impairment and even end-stage renal disease. We treated a 42-year-old female patient with proteinuria who presented with a web-like structure over the antecubital fossa and hypoplastic patellae. In addition, she had other characteristic findings, including bilateral iliac horn, triangular nail lunulae and hypoplastic radial head. She had impaired renal function, and renal biopsy showed mesangial proliferative glomerulonephritis. Additional cases were found in her family. Her mother had most of the signs of NPS as well as advanced renal failure. Her elder sister had knee abnormalities without the web-like elbow condition. Both daughters also had the characteristic features of NPS. During follow-up 30 months after the initial examination, the patient had stable renal function and mild proteinuria.

Adult↗
PubMedDate not supplied

Higher frequency of apolipoprotein E2 allele in type 2 diabetic patients with nephropathy in Taiwan.

BACKGROUND: Diabetes is one of the major causes of end stage renal failure in Taiwan. Previous studies have indicated that lipid abnormalities might contribute to the development and progression of diabetic nephropathy (DN). Apolipoprotein E (apo E) regulates the metabolism of lipoproteins. Three different apo E alleles (epsilon2, epsilon3 and epsilon4) produce apo E isoproteins, apo E2, apo E3 and apo E4. Thus, the apo E gene polymorphism may be associated with DN. METHODS: To investigate the distribution of apo E genotype in type 2 diabetic Taiwanese, we examined 314 patients with type 2 diabetes (100 without nephropathy and 214 with nephropathy) and 150 age-matched normal controls. The diagnosis of nephropathy was made when daily protein loss exceeded 500 mg. The apo E gene polymorphism was analyzed by polymerase chain reaction. RESULTS: Our study found that the frequency of apo E2 allele was significantly higher in the diabetics with nephropathy- non-dialysis group (7.7%) and diabetics with nephropathy- dialysis group (7.7%) than in normal controls (1.7%) (p < 0.001) and diabetics without nephropathy (2.0%) (p < 0.01). The E3 and E4 allele frequencies were not significantly different among groups. CONCLUSION: These findings imply that apo E polymorphism is apparently related to the development of DN in type 2 diabetes in Taiwan.

Adult↗
PubMedDate not supplied

Comparison of peritoneal equilibrium test with icodextrin and 2.5% glucose dialysis solutions.

BACKGROUND: Icodextrin provides a different ultrafiltration mechanism than glucose-based dialysate. METHODS: To evaluate the difference in the peritoneal equilibrium test (PET) with regard to using icodextrin (Ico-PET) and glucose dialysate we designed a prospective study using Ico-PET and 2 cross-over conventional 2.5% glucose-based dialysate PETs (Gluco 1-PET and Gluco 2-PET) administered 3 months before and after the Ico-PET in 58 chronic peritoneal dialysis patients. RESULTS: More patients demonstrated higher transport types with the Ico-PET than the Gluco 1-PET and Gluco 2-PET (p<0.001). After a dwell time of 4 hours, the Ico-PET did not show an ultrafiltration benefit compared with the Gluco-PET (272.8 +/- 137.1 mL vs. 348.3 +/- 215.2 mL, p<0.001). The Ico-PET not only showed significantly higher values in the 0-hour, 2-hour and 4-hour dialysate to plasma creatinine concentration ratio (D/P Cr) than those of the Gluco 1-PET (p=0.029 and p<0.001, respectively), but also showed higher values in the 0-hour and 4-hour D/P Cr than those of the Gluco 2-PET (both p<0.001). The total ultrafiltration volume was positively correlated with the 4-hour D/P Cr with the Ico-PET (r=0.41, p=0.001), but the correlation was negative with the Gluco 1-PET (r=-0.33, p=0.012) and Gluco 2-PET (r=-0.51, p<0.001). The ratio of the glucose concentration in the outflow dialysate compared with baseline level (D/Do glucose), was also significantly higher with the Ico-PET than with the Gluco 1-PET and Gluco 2-PET after both 2 and 4 hours (both p<0.001). CONCLUSIONS: The Ico-PET showed a completely different result from the conventional Gluco-PET. The Ico-PET provi-des a superior solute transport and inferior ultrafiltration rates, and the prevalence of high transporters was also increased with the Ico-PET.

Adult↗