Efficacy and safety of whole body vibration in maintenance hemodialysis patients - A pilot study.

OBJECTIVES: The aim of this study was to assess safety and effectiveness of Whole Body Vibration exercise (WBV) to improve physical performance and parameters of inflammation in patients on maintenance hemodialysis (MHD). METHODS: Prospective, open-label trial in n=14 patients on maintenance hemodialysis. Participants performed WBV twice weekly for 12 weeks before (n=8) or after (n=6) hemodialysis sessions. The primary endpoint was physical performance assessed by the Short-Physical-Performance-Battery (SPPB). Secondary endpoints included established parameters of musculoskeletal assessment and blood chemistry. RESULTS: As compared to baseline, physical performance (SPPB) improved significantly (p=0.035). Moderate advances were also seen for 6-Minute-Walking test, Timed-up-and-go test, jumping height and handgrip strength. Improvements were particularly pronounced in subjects with seriously impaired baseline performance. Skeletal muscle index showed a tendency to better values. Laboratory data exhibited a significant reduction of white blood cell count and a trend to lower levels of hsCRP. WBV was generally well tolerated. Two events of clinically significant blood pressure decline occurred in patients exercising after dialysis sessions. CONCLUSIONS: Results of this pilot study suggest effectiveness and safety of WBV in hemodialysis patients. Beneficial effects may affect both, parameters of physical performance and systemic inflammatory activity, which should be verified in larger scale clinical trials.

Is vitamin D deficiency related to accumulation of advanced glycation end products, markers of inflammation, and oxidative stress in diabetic subjects?

OBJECTIVES: In diabetes accumulated advanced glycation end products (AGEs) are involved in the striking cardiovascular morbidity/mortality. We asked whether a hypovitaminosis D associates with an increased formation and toxicity of AGEs in diabetes. METHODS: In 276 diabetics (160 M/116 F, age: 65.0 ± 13.4; 43 type 1,T1DM, and 233 type 2 patients, T2DM) and 121 nondiabetic controls (60 M/61 F; age: 58.6 ± 15.5 years) routine biochemistry, levels of 25-hydroxyvitamin D3 (25-(OH)D), skin autofluorescence (SAF), plasma AGE-associated fluorescence (AGE-FL), N (ε) -(carboxymethyl)lysine (CML), soluble receptor for AGEs (sRAGE), soluble vascular adhesion protein-1 (sVAP-1), high sensitive C-reactive protein (hs-CRP), and renal function (eGFR) were determined. RESULTS: In the diabetics SAF and AGE-Fl were higher than those of the controls and correlated with age, duration of diabetes, and degree of renal impairment. In T2DM patients but not in T1DM the age-dependent rise of SAF directly correlated with hs-CRP and sVAP-1. 25-(OH)D levels in diabetics and nondiabetics were lowered to a similar degree averaging 22.5 ng/mL. No relationship between 25-(OH)D and studied markers except for sVAP-1 was observed in the diabetics. CONCLUSION: In diabetics hypovitaminosis D does not augment accumulation of AGEs and studied markers of microinflammation and oxidative stress except for sVAP-1.

Aldosterone causes DNA strand breaks and chromosomal damage in renal cells, which are prevented by mineralocorticoid receptor antagonists.

Epidemiological studies exploring the connection between hypertension and cancer incidence find a higher cancer mortality in hypertensive patients, particularly elevated in hypertension associated with a stimulation of the renin-angiotensin-aldosterone system. Primary aldosteronism, with plasma aldosterone levels between 0.5 and 1 nM (18-36 ng/dL) and local aldosterone levels up to 500 nM (18,000 ng/dL), is now recognised as a more common cause for hypertension. We recently found angiotensin II to be genotoxic due to its induction of oxidative stress. Since aldosterone in higher concentrations also has oxidative effects, its potential genotoxic action in pig LLC-PK1 cells with properties of proximal tubules was analysed. DNA damage was evaluated by two test systems: the comet assay, and the micronucleus frequency test. The results showed that aldosterone concentrations starting from 10 nM (360 ng/dL) caused a significant increase of DNA damage monitored with the comet assay in LLC-PK1, while there was no change in cell vitality and proliferation. The micronucleus frequency test revealed that 10 nM aldosterone also leads to the formation of micronuclei. Furthermore, the formation of superoxide radicals in the cells by this aldosterone concentration could be detected with the superoxide-specific stain dihydroethidium. Further evidence for oxidative stress-induced DNA damage was its reversibility by the antioxidants tempol and catalase. Addition of the steroidal mineralocorticoid receptor antagonist spironolactone or the novel selective nonsteroidal antagonist (R)-BR-4628 reduced the DNA damage and the amount of superoxide radicals indicating a receptor-dependent process.

Neuronal activation in the CNS during different forms of acute renal failure in rats.

The effect of experimentally induced acute renal failure (ARF) on neuronal cell activation was investigated by immunohistochemistry for Fos and Fra-2 in the rat brain. ARF in rats was induced by bilateral nephrectomy (BNX), bilateral ureter ligature (BUL) and uranyl acetate injection with proper controls (sham-operation or saline injections, respectively). To follow the effect of the development of ARF, rats were killed 30 and 60 min, and 3, 12, 24 and 72 h after surgery, or 3 h to 12 days after uranyl acetate injections. In the BUL and BNX rats, urea and creatinine rose markedly in the plasma within 72 h, while in the uranyl acetate-injected rats the highest levels were observed on the 7th day, followed by a marked decline. At each time-point of the three different, experimentally induced ARF, the presence of Fos- and/or Fra-2-immunoreactive neurons was determined in 120 different brain areas and nuclei. In general, the 73 of 120 brain areas that showed time and intensity dependent activation in response to ARF can be classified into four groups: 1) biogenic amine (noradrenaline, adrenaline, histamine and 5-HT) expressing cell groups in the lower brainstem, 2) "stress-sensitive" forebrain areas, with regard to certain hypothalamic, limbic and cortical areas, 3) neuronal cell groups that participate in the central regulation of body and brain water and electrolyte homeostasis, including the circumventricular organs, and 4) central autonomic cell groups, especially visceral sensory cell groups in the brain, which are in primary, secondary or tertiary connections with renal afferents. Data presented here indicate that a wide variety of neurons in several regulatory mechanisms is affected by ARF-induced peripheral and central alterations.

High-tone external muscle stimulation in end-stage renal disease: effects on symptomatic diabetic and uremic peripheral neuropathy.

OBJECTIVE AND DESIGN: Pain and peripheral neuropathy are frequent complications of end-stage renal disease (ESRD). Because drug treatment is associated with numerous side effects and is largely ineffective in many maintenance hemodialysis (MHD) patients, nonpharmacologic strategies such as electrotherapy are a potential recourse. Among various forms of electrostimulation, high-tone external muscle stimulation (HTEMS) is a promising alternative treatment for symptomatic diabetic peripheral polyneuropathy (PPN), as demonstrated in a short-term study. Based on these novel findings, we performed a prospective, nonrandomized, pilot trial in MHD patients to determine (1) whether HTEMS is also effective in treating diabetic PPN in the uremic state, and (2) whether uremic PPN is similarly modulated. PATIENTS AND INTERVENTIONS: In total, 40 MHD patients diagnosed with symptomatic PPN (25 with diabetic and 15 with uremic PPN) were enrolled. Both lower extremities were treated intradialytically with HTEMS for 1 hour, three times a week. Initially, a subgroup of 12 patients was followed for 4 weeks, and a further 28 patients for 12 weeks. The patients' degree of neuropathy was graded at baseline before HTEMS and after 1 and 3 months, respectively. Five neuropathic symptoms (tingling, burning, pain, numbness, and numbness in painful areas) as well as sleep disturbances were measured, using the 10-point Neuropathic Pain Scale of Galer and Jensen (Neurology 48:332-338, 1997). A positive response was defined as the improvement of one symptom or more, by at least 3 points. Other parameters included blood pressure, heart rate, dry body weight, and a routine laboratory investigation. RESULTS: The HTEMS led to a significant improvement in all five neuropathic symptoms, and to a significant reduction in sleep disturbances for both diabetic and uremic PPN. The response was independent of the patient's age, with a responder rate of 73%. The improvement of neuropathy was time-dependent, with the best results achieved after 3 months of treatment. The HTEMS was well-tolerated by nearly all patients. CONCLUSIONS: This pilot study shows for the first time that HTEMS can ameliorate the discomfort and pain associated with both diabetic and uremic PPN in MHD patients, and could be a valuable supplement in the treatment of pain and neuropathic discomfort in patients who do not respond to, or are unable to participate in, exercise programs during hemodialysis treatment.

Accumulation of free adduct glycation, oxidation, and nitration products follows acute loss of renal function.

Glycation, oxidation, and nitration of endogenous proteins occur spontaneously and these modifications are also present in foods. Increased levels of these chemical changes are associated with chronic renal failure; however, little is known about acute kidney failure. We measured these modifications of plasma protein and related free adducts in plasma following bilateral nephrectomy and bilateral ureteral obstruction. Advanced glycation end-product (AGE) residues of plasma protein were increased 3 h post-surgery, and thereafter slowly decreased in all groups, reflecting changes in plasma protein synthesis and transcapillary flow post-surgery. Ureteral ligation increased oxidation and nitration adduct residues. There were, however, marked increases in AGE, dityrosine, or 3-nitrotyrosine free adducts in both nephrectomized and ureter-ligated rats compared to rats that had undergone sham operations. There were lower modified adduct concentrations in the ureter-ligated compared to the nephrectomized rats, reflecting residual glomerular filtration and tubular removal. There was no increase in glycated, oxidized, and nitrated proteins. Glyoxal and methylglyoxal were also increased in both renal failure models. Our study shows that the acute loss of renal function and urinary excretion leads to the accumulation of AGE, oxidation, and nitration free adducts in the plasma.

Homocysteine exerts genotoxic and antioxidative effects in vitro.

INTRODUCTION: Patients with end-stage renal disease suffer from increased genomic damage and cancer incidence. One possible reason is the accumulation of uremic toxins such as homocysteine (Hcy). Elevated Hcy levels--usually indicative of cardiovascular events--correlated with the genomic damage in cross-sectional studies. Therefore we investigated the genotoxic effects of Hcy in vitro. METHODS: To analyse the genomic damage, micronucleus tests and the comet-assay were performed in L5178Y and HL60 cells. Additionally, the influence of Hcy on cell cycle progression, DNA-cytosine-methylation, oxidative stress levels and on the cellular glutathione content were determined. RESULTS: Low millimolar concentrations of Hcy-induced micronuclei in both cell lines but did not enhance the DNA damage observed with the comet-assay. Cell cycle progression was inhibited in S-phase, while DNA-cytosine-methylation remained unchanged. Furthermore, Hcy protected cells challenged with H(2)O(2) from oxidative stress. This was accompanied by an increased cellular glutathione level. CONCLUSION: Since the genotoxic effect was limited to high Hcy concentrations, a contribution of Hcy to the enhanced genomic damage in end-stage renal disease patients would only be conceivable upon local Hcy accumulation. Whether the detected antioxidant capacity of Hcy is relevant for any situation in patients remains to be elucidated.

Relation between different treatment modalities and genomic damage of end-stage renal failure patients.

BACKGROUND: Patients with end-stage renal disease display enhanced genomic damage. We investigated the relation between genomic damage and different treatment modalities. METHODS: In a longitudinal study two groups of patients were analyzed in monthly intervals. We assessed the initiation of hemodialysis in 5 conservatively treated patients, and a switch from hemodialysis to hemodiafiltration in 7 patients. DNA damage was investigated in peripheral blood lymphocytes by micronucleus frequency and by comet assay analysis. With regard to potential genotoxicity of advanced glycation end products (AGEs), levels of imidazolone A and AGE-associated fluorescence (AGE-FL) were determined. RESULTS: The initiation of hemodialysis did not alter the genomic damage. In patients who switched from hemodialysis to hemodiafiltration, a small but significant reduction in the comet assay but not in the micronucleus frequency was observed. Elevated plasma levels of imidazolone A and AGE-FL were not influenced by the treatment modalities. CONCLUSION: In our small patient group no major reduction of the elevated genomic damage could be reached. Disease factors not influenced by altered dialysis modalities may have contributed considerably in our patient group. The persisting high levels of DNA damage suggest a need for further improvement. Inhibiting AGE formation may be one promising way for the future.

Oxidative stress and non-enzymatic glycation in IgA nephropathy.

AIM: Approximately 20-50% of IgA nephropathy patients develop end-stage renal disease. We have previously found enhanced oxidative stress and decreased antioxidant capacity in red blood cells of IgA nephropathy patients. In this study we assess oxidative stress, non-enzymatic glycation, oxidative resistance of low-density lipoprotein and its alpha-tocopherol content in these patients. PATIENTS AND METHODS: Non-enzymatic glycation and oxidative stress were assessed in 88 IgA nephropathy patients by measuring advanced glycation end products, Nepsilon-carboxymethyl-lysine, thiobarbituric acid reactive substances, oxidative resistance of low-density lipoprotein and its alpha-tocopherol content. RESULTS: Advanced glycation end products (2659 +/- 958 a.u.) and Nepsilon-carboxymethyl-lysine (563 +/- 215 ng/ml) were significantly higher in IgA nephropathy patients with decreased renal function compared to those with normal renal function (p < 0.002) or controls (p < 0.001). Thiobarbituric acid-reactive substances in plasma and associated with low-density lipoprotein were significantly elevated and oxidative resistance of low-density lipoprotein was significantly reduced in all groups of IgA nephropathy patients. There was no significant difference in circulating fluorescent advanced glycation end products, Nepsilon-carboxymethyl-lysine, thiobarbituric acid-reactive substances levels, oxidative resistance of low-density lipoprotein and its alpha-tocopherol content between patients with normal vs. impaired glucose metabolism. Low alpha-tocopherol content of low-density lipoprotein was accompanied with decreased oxidative resistance, depletion in polyunsaturated fatty acids, elevated saturated fatty acids and thiobarbituric acid-reactive substances within low-density lipoprotein suggesting enhanced lipid peroxidation. CONCLUSIONS: Decreased oxidative resistance of low-density lipoprotein and enhanced oxidative stress are common features in IgA nephropathy, while increased non-enzymatic glycation occurs as renal function declines.

Pilot study for comparison of reticulocyte-micronulei with lymphocyte-micronuclei in human biomonitoring.

Biomonitoring tries to determine the consequences for humans of exposures to environmental or pharmaceutical agents. Different end points have been employed to assess the burden of genomic damage. This is the first report comparing a recently introduced new end point, the reticulocyte-micronuclei analyzed by flow cytometry with the widely used lymphocyte-micronucleus assay, applied to two exposure scenarios leading to enhanced genomic damage. Radioiodine therapy was chosen to represent a short time exposure and hemodialysis treatment in end-stage renal failure was chosen to represent a chronic exposure. The results show that iodine radiation induced measurable genomic damage in the lymphocyte-micronucleus assay as well as in the reticulocyte-micronucleus test. Of two groups of patients under hemodialysis treatment, a reduced genomic damage was found with the lymphocyte-micronucleus test, but not with the reticulocyte-micronucleus test in the group undergoing daily hemodialysis, which removes uremic toxins more efficiently as compared to conventional hemodialysis, the treatment applied in the other group. The limited life-span of reticulocytes may make them less suitable for accumulation of chronic low level damage than lymphocytes. In conclusion, the lymphocyte-micronucleus test may be applicable to more exposure situations (including low chronic exposure), but the reticulocyte-micronucleus assay may be easier to perform in a clinical setting. The latter reflects a more rapid reduction of genomic damage after an acute exposure.

Paradox of circulating advanced glycation end product concentrations in patients with congestive heart failure and after heart transplantation.

OBJECTIVES: To analyse circulating concentrations of advanced glycation end products (AGEs) in patients with severe congestive heart failure (CHF) and after heart transplantation; to identify the potential contribution of kidney function to plasma AGE concentrations; and to determine whether AGE concentrations and parameters of oxidative stress are interrelated. METHODS AND RESULTS: Circulating N(epsilon)-(carboxymethyl)lysine (CML) and AGE associated fluorescence (AGE-Fl), lipid peroxidation, and glomerular filtration rate (GFR) were measured in a cross sectional study of 22 patients with advanced CHF, 30 heart transplant recipients, and 20 healthy controls. Compared with the controls, the CHF patients had decreased CML (mean (SEM) 467.8 (20.0) ng/ml v 369.3 (22.3) ng/ml, p < 0.01), AGE-Fl (mean (SEM) 302.2 (13.3) arbitrary units v 204.9 (15.7) arbitrary units, p < 0.01), and GFR (p < 0.01). CML was positively related to decreased total protein and serum albumin and negatively to body mass index (p < 0.01). In contrast, in the heart transplant group, impaired GFR was associated with a notable rise of both CML (mean (SEM) 876.1 (53.1) ng/ml, p < 0.01) and AGE-Fl (mean (SEM) 385.6 (26.1) arbitrary units, p < 0.01). A positive relation between CML and serum albumin (r = 0.394, p < 0.05) and lipofuscin (r = 0.651, p < 0.01) was found. CONCLUSIONS: The contrasting concentration of CML and AGE-Fl between patients with CHF and after heart transplantation in the presence of decreased GFR and oxidative stress are explained by lowered plasma proteins in CHF and higher concentrations in heart transplant recipients. In heart transplant recipients, in addition to myocardial inflammatory processes, immunosuppression may be important for enhanced formation of AGEs.

[Overweight and obesity--risk factors in the development and progression of renal disease]. / Nadváha a obezita--faktory podmienujúce vývin a progresiu ochorení obliciek.

Overweight/obesity represent an underestimated risk factor of renal disease. The incidence of obesity-related glomerulopathy (ORG) tremendously increased within the last decade. The first sign of renal damage in overweight conditions is microalbuminuria or proteinuria, indicating the potential risk of its progression to renal insufficiency and the development of premature cardiovascular events. In the early stage of obesity renal hemodynamics are characterized by a renal hypercirculation and glomerular hyperfiltration, particularly in the presence of hypertension. The hyperfiltration is especially harmful in patients with pre-existing inflammatory and metabolic renal disease, or under the conditions of reduced renal mass. Histopathologically, ORG is characterized by glomerulomegaly with/without signs of focal segmental glomerulosclerosis. Pathogenetically, numerous factors are involved, e.g. enhanced glomerular capillary pressure, adrenergic nerve overactivity, inappropriate activation of the renin-angiotensin-aldosterone system, insulin resistance, hyperinsulinemia and hyperleptinemia, dyslipidemia, enhanced clotting tendency and sodium retention. Diabetic nephropathy is one of the most serious complications of obesity-induced diabetes. In the industrial nations type 2 diabetes is the single most frequent cause of end-stage renal disease. After kidney transplantation, overweight/obesity is associated with a less favourable prognosis for the survival of the graft and the patient. Incidence of renal cell carcinomas is enhanced in overweight/obesity. Obesity-related renal disease may be prevented/postponed by an early weight reduction, by dietary intervention combined with physical exercise. In the advanced stages of renal disease benefits of weight reduction are minimal. Concomitant administration of angiotensin-converting-enzyme inhibitors or angiotensin II receptor 1 blockers exerts antiproteinuric effects and thereby aid in retarding the disease progression. Aimed prevention and treatment of obesity represent a challenge for the healthcare system. The concerted action of physicians, patients and the public health authorities is needed.

Effects of ramipril in nondiabetic nephropathy: improved parameters of oxidatives stress and potential modulation of advanced glycation end products.

Enhanced oxidative stress is involved in the progression of renal disease. Since angiotensin converting enzyme inhibitors (ACEI) have been shown to improve the antioxidative defence, we investigated, in patients with nondiabetic nephropathy, the short-term effect of the ACEI ramipril on parameters of oxidative stress, such as advanced glycation end products (AGEs), advanced oxidation protein products (AOPPs), homocysteine (Hcy), and lipid peroxidation products. Ramipril (2.5-5.0 mg/day) was administered to 12 newly diagnosed patients for 2 months and data compared with a patient group under conventional therapy (diuretic/beta-blockers) and with age- and sex-matched healthy subjects (CTRL). Patients had mild to moderate renal insufficiency and showed, in the plasma, higher fluorescent AGE and carboxymethyllysine (CML) levels, as well as elevated concentrations of AOPPs, lipofuscin and Hcy when compared with CTRL. Basal data of the patients on conventional therapy did not differ significantly from the ramipril group, except for higher Hcy levels in the latter. Administration of ramipril resulted in a drop in blood pressure and proteinuria, while creatinine clearance remained the same. The fluorescent AGEs exhibited a mild but significant decline, yet CML concentration was unchanged. The AOPP and malondialdehyde concentrations decreased, while a small rise in neopterin levels was evident after treatment. The mentioned parameters were not affected significantly in the conventionally treated patients. Evidence that ramipril administration results in a mild decline of fluorescent AGEs is herein presented for the first time. The underlying mechanism may be decreased oxidative stress, as indicated by a decline in AOPPs and malondialdehyde.

Relationship between plasma level of parathyroid hormone and carboxymethyllysine in hemodialyzed patients--does it exist?

AIMS: Both parathyroid hormone and advanced glycated end products (AGEs) are uremic toxins. The present study aimed to examine the likely interrelationship between these compounds. METHODS: Seventy-four hemodialyzed patients (41 female, 33 male; mean age 47 +/- 2 years, mean duration on hemodialysis 36 +/- 6 months) were enrolled in this study. In all subjects, the body mass index (BMI) was calculated and total lean mass (TLM) and total fat mass (TFM) were assessed by dual X-ray absorptiometry. Blood samples for estimation of plasma calcium, phosphorus, carboxymethyl lysine (as marker of AGEs) and PTH-1-84 were obtained after overnight fasting, before subsequent hemodialysis session. RESULTS: BMI, TFM and TLM were 23.6 +/- 0.5 kg/m2, 16.3 +/- 1.0 kg and 46.3 +/- 1.1 kg, respectively. PTH plasma level (223 +/- 32 pg/ml) and plasma CML (1,837 +/- 84 ng/ml) were markedly elevated as compared with reference values. A significant positive correlation was found between TLM and CML levels (tau = 0.225; p = 0.04) and between plasma PTH and CML levels (tau = 0.224; p = 0.04). CONCLUSION: It seems likely that PTH and AGEs are interrelated. The pathophysiological relevance of this finding in the pathogenesis of uremic toxicity remains to be elucidated.

[Incidence and spectrum of malignant disease among dialysis patients in North Bavaria]. / Inzidenz und Spektrum maligner Erkrankungen bei Dialysepatienten in Nordbayern.

BACKGROUND AND OBJECTIVE: In end-stage renal failure the incidence of cancer is increased. With regard to frequency and pattern of distribution of the tumors, there are substantial regional differences. Since this topic has to date received only minimal attention in Germany, we undertook a multi-centric analysis (8 dialysis centres) in North Bavaria in order to address the occurrence of malignant diseases in end-stage renal failure. PATIENTS AND METHODS: Of a total of 2228 patients, who underwent hemodialysis in the period from 1990 - 99 as a consequence of end-stage renal failure, the medical records of 1727 persons were analysed. Only those patients were considered, whose malignancy was diagnosed in the course of the dialysis. The Saarland cancer register served as a comparative age- and sex-matched population, with which we calculated the expected frequency of the various cancers as well as the standard incidence ratio (SIR) for the dialysis patients. RESULTS: In total 125 malignant diseases were documented. The cancer incidence was highest in the first year of treatment and was clearly lower in the subsequent periods. Of great importance was the age of the patients. The highest SIR scores were found for patients of middle age (35 - 50 years). An enhanced risk for cancer of the kidney, bladder, prostate, liver, oral cavity and the pharynx and larynx, as well as of the lymphatic and hemopoetic systems was found, while there was no or only a slight increase in the frequency of carcinoma of the mammary gland, stomach, colon-sigma-rectum and bronchial systems. CONCLUSION: The high incidence of cancer in end-stage renal failure should be given greater attention. Particularly in the high-risk group of younger dialysis patients, a regular screening - especially for tumors of the kidney, bladder and liver - appears justified.

Advanced glycation end products and the progressive course of renal disease.

In experimental and human diabetic nephropathy (DN), it has been shown that advanced glycation end products (AGEs), in particular, carboxymethyl-lysine and pentosidine, accumulate with malondialdehyde in glomerular lesions in relation to disease severity and in the presence of an upregulated receptor for AGE (RAGE) in podocytes. Toxic effects of AGEs result from structural and functional alterations in plasma and extracellular matrix (ECM) proteins, in particular, from cross-linking of proteins and interaction of AGEs with their receptors and/or binding proteins. In mesangial and endothelial cells, the AGE-RAGE interaction caused enhanced formation of oxygen radicals with subsequent activation of nuclear factor-kappaB and release of pro-inflammatory cytokines (interleukin-6, tumor necrosis factor-alpha), growth factors (transforming growth factor-beta1 [TGF-beta1], insulin-like growth factor-1), and adhesion molecules (vascular cell adhesion molecule-1, intercellular adhesion molecule-1). In tubular cells, incubation with AGE albumin was followed by stimulation of the mitogen-activating protein (MAP) kinase pathway and its downstream target, the activating protien-1 (AP-1) complex, TGF-beta1 overexpression, enhanced protein kinase C activity, decreased cell proliferation, and impaired protein degradation rate, in part caused by decreased cathepsin activities. The pathogenic relevance of AGEs was further verified by in vivo experiments in euglycemic rats and mice by the parenteral administration of AGE albumin, leading in the glomeruli to TGF-beta1 overproduction, enhanced gene expression of ECM proteins, and morphological lesions similar to those of DN. Evidence for the pathogenic relevance of AGEs in DN also comes from experimental studies in which the formation and/or action of AGEs was modulated by aminoguanidine, OPB-9195, pyridoxamine, soluble RAGEs, serine protease trypsin, and antioxidants, resulting in improved cell and/or renal function.